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authorSiep Kroonenberg <siepo@cybercomm.nl>2011-02-17 17:31:37 +0000
committerSiep Kroonenberg <siepo@cybercomm.nl>2011-02-17 17:31:37 +0000
commit227723589c9564b9b2b7042dd27eb9aad56a560a (patch)
tree5185d4773197a8bc419342ca26b1db30dc992b5a /Master/tlpkg/tlperl
parent98f44e1fb37d3dbed7ffbc066daac04371ed6f3a (diff)
New tlperl part XI
git-svn-id: svn://tug.org/texlive/trunk@21433 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Master/tlpkg/tlperl')
-rw-r--r--Master/tlpkg/tlperl/lib/pods/a2p.pod179
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl.pod462
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5004delta.pod1612
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5005delta.pod993
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5100delta.pod1612
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5101delta.pod1772
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5110delta.pod1624
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5111delta.pod365
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5112delta.pod348
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5113delta.pod558
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5114delta.pod278
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5115delta.pod327
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5120delta.pod3200
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5121delta.pod412
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5122delta.pod346
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl5123delta.pod116
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl561delta.pod3661
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl56delta.pod3022
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl570delta.pod899
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl571delta.pod1075
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl572delta.pod831
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl573delta.pod246
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl581delta.pod1102
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl582delta.pod162
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl583delta.pod210
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl584delta.pod263
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl585delta.pod257
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl586delta.pod170
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl587delta.pod379
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl588delta.pod1632
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl589delta.pod2336
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl58delta.pod3746
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl590delta.pod1015
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl591delta.pod323
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl592delta.pod342
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl593delta.pod549
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl594delta.pod382
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perl595delta.pod587
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlaix.pod494
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlamiga.pod278
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlapi.pod9328
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlapio.pod526
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlapollo.pod23
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlartistic.pod224
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlbeos.pod109
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlbook.pod17
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlboot.pod884
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlbot.pod535
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlbs2000.pod241
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcall.pod1935
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlce.pod306
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcheat.pod93
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlclib.pod212
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcn.pod150
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcommunity.pod158
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcompile.pod293
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlcygwin.pod784
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldata.pod867
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldbmfilter.pod168
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldebguts.pod879
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldebtut.pod723
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldebug.pod1175
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldelta.pod116
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldgux.pod117
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldiag.pod5267
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldoc.pod270
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldos.pod331
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perldsc.pod847
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlebcdic.pod1424
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlembed.pod1160
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlepoc.pod154
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq.pod1444
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq1.pod410
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq2.pod550
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq3.pod1097
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq4.pod2588
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq5.pod1545
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq6.pod1143
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq7.pod1072
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq8.pod1416
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfaq9.pod682
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfilter.pod587
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfork.pod323
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlform.pod459
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfreebsd.pod47
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlfunc.pod7737
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlglossary.pod3408
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlgpl.pod287
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlguts.pod2674
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlhack.pod3401
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlhaiku.pod64
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlhist.pod886
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlhpux.pod657
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlhurd.pod54
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlintern.pod2961
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlintro.pod678
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perliol.pod1039
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlipc.pod1854
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlirix.pod137
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perljp.pod192
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlko.pod207
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perllexwarn.pod529
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perllinux.pod39
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perllocale.pod1046
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perllol.pod303
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmacos.pod34
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmacosx.pod270
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmod.pod598
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmodinstall.pod454
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmodlib.pod3513
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmodstyle.pod780
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmpeix.pod711
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlmroapi.pod94
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlnetware.pod214
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlnewmod.pod280
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlnumber.pod209
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlobj.pod595
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlop.pod2586
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlopenbsd.pod30
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlopentut.pod981
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlos2.pod2741
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlos390.pod444
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlos400.pod120
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlpacktut.pod1266
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlperf.pod1179
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlplan9.pod146
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlpod.pod737
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlpodspec.pod1923
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlpolicy.pod376
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlport.pod2345
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlpragma.pod147
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlqnx.pod143
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlre.pod2081
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlreapi.pod699
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlrebackslash.pod583
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlrecharclass.pod699
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlref.pod686
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlreftut.pod527
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlreguts.pod886
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlrepository.pod908
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlrequick.pod516
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlreref.pod392
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlretut.pod2879
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlriscos.pod67
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlrun.pod1332
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlsec.pod520
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlsolaris.pod690
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlstyle.pod303
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlsub.pod1513
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlsymbian.pod433
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlsyn.pod934
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlthrtut.pod1176
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltie.pod1204
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltoc.pod35597
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltodo.pod1302
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltooc.pod1342
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltoot.pod1836
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltrap.pod1590
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltru64.pod172
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perltw.pod172
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlunicode.pod1762
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlunifaq.pod319
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perluniintro.pod892
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perluniprops.pod3051
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlunitut.pod208
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlutil.pod309
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perluts.pod107
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlvar.pod1780
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlvmesa.pod131
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlvms.pod1226
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlvos.pod169
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlwin32.pod1031
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlxs.pod2126
-rw-r--r--Master/tlpkg/tlperl/lib/pods/perlxstut.pod1378
174 files changed, 207441 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/pods/a2p.pod b/Master/tlpkg/tlperl/lib/pods/a2p.pod
new file mode 100644
index 00000000000..d32a9c7efa1
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/a2p.pod
@@ -0,0 +1,179 @@
+=head1 NAME
+
+a2p - Awk to Perl translator
+
+=head1 SYNOPSIS
+
+B<a2p> [I<options>] [I<filename>]
+
+=head1 DESCRIPTION
+
+I<A2p> takes an awk script specified on the command line (or from
+standard input) and produces a comparable I<perl> script on the
+standard output.
+
+=head2 OPTIONS
+
+Options include:
+
+=over 5
+
+=item B<-DE<lt>numberE<gt>>
+
+sets debugging flags.
+
+=item B<-FE<lt>characterE<gt>>
+
+tells a2p that this awk script is always invoked with this B<-F>
+switch.
+
+=item B<-nE<lt>fieldlistE<gt>>
+
+specifies the names of the input fields if input does not have to be
+split into an array. If you were translating an awk script that
+processes the password file, you might say:
+
+ a2p -7 -nlogin.password.uid.gid.gcos.shell.home
+
+Any delimiter can be used to separate the field names.
+
+=item B<-E<lt>numberE<gt>>
+
+causes a2p to assume that input will always have that many fields.
+
+=item B<-o>
+
+tells a2p to use old awk behavior. The only current differences are:
+
+=over 5
+
+=item *
+
+Old awk always has a line loop, even if there are no line
+actions, whereas new awk does not.
+
+=item *
+
+In old awk, sprintf is extremely greedy about its arguments.
+For example, given the statement
+
+ print sprintf(some_args), extra_args;
+
+old awk considers I<extra_args> to be arguments to C<sprintf>; new awk
+considers them arguments to C<print>.
+
+=back
+
+=back
+
+=head2 "Considerations"
+
+A2p cannot do as good a job translating as a human would, but it
+usually does pretty well. There are some areas where you may want to
+examine the perl script produced and tweak it some. Here are some of
+them, in no particular order.
+
+There is an awk idiom of putting int() around a string expression to
+force numeric interpretation, even though the argument is always
+integer anyway. This is generally unneeded in perl, but a2p can't
+tell if the argument is always going to be integer, so it leaves it
+in. You may wish to remove it.
+
+Perl differentiates numeric comparison from string comparison. Awk
+has one operator for both that decides at run time which comparison to
+do. A2p does not try to do a complete job of awk emulation at this
+point. Instead it guesses which one you want. It's almost always
+right, but it can be spoofed. All such guesses are marked with the
+comment "C<#???>". You should go through and check them. You might
+want to run at least once with the B<-w> switch to perl, which will
+warn you if you use == where you should have used eq.
+
+Perl does not attempt to emulate the behavior of awk in which
+nonexistent array elements spring into existence simply by being
+referenced. If somehow you are relying on this mechanism to create
+null entries for a subsequent for...in, they won't be there in perl.
+
+If a2p makes a split line that assigns to a list of variables that
+looks like (Fld1, Fld2, Fld3...) you may want to rerun a2p using the
+B<-n> option mentioned above. This will let you name the fields
+throughout the script. If it splits to an array instead, the script
+is probably referring to the number of fields somewhere.
+
+The exit statement in awk doesn't necessarily exit; it goes to the END
+block if there is one. Awk scripts that do contortions within the END
+block to bypass the block under such circumstances can be simplified
+by removing the conditional in the END block and just exiting directly
+from the perl script.
+
+Perl has two kinds of array, numerically-indexed and associative.
+Perl associative arrays are called "hashes". Awk arrays are usually
+translated to hashes, but if you happen to know that the index is
+always going to be numeric you could change the {...} to [...].
+Iteration over a hash is done using the keys() function, but iteration
+over an array is NOT. You might need to modify any loop that iterates
+over such an array.
+
+Awk starts by assuming OFMT has the value %.6g. Perl starts by
+assuming its equivalent, $#, to have the value %.20g. You'll want to
+set $# explicitly if you use the default value of OFMT.
+
+Near the top of the line loop will be the split operation that is
+implicit in the awk script. There are times when you can move this
+down past some conditionals that test the entire record so that the
+split is not done as often.
+
+For aesthetic reasons you may wish to change index variables from being
+1-based (awk style) to 0-based (Perl style). Be sure to change all
+operations the variable is involved in to match.
+
+Cute comments that say "# Here is a workaround because awk is dumb"
+are passed through unmodified.
+
+Awk scripts are often embedded in a shell script that pipes stuff into
+and out of awk. Often the shell script wrapper can be incorporated
+into the perl script, since perl can start up pipes into and out of
+itself, and can do other things that awk can't do by itself.
+
+Scripts that refer to the special variables RSTART and RLENGTH can
+often be simplified by referring to the variables $`, $& and $', as
+long as they are within the scope of the pattern match that sets them.
+
+The produced perl script may have subroutines defined to deal with
+awk's semantics regarding getline and print. Since a2p usually picks
+correctness over efficiency. it is almost always possible to rewrite
+such code to be more efficient by discarding the semantic sugar.
+
+For efficiency, you may wish to remove the keyword from any return
+statement that is the last statement executed in a subroutine. A2p
+catches the most common case, but doesn't analyze embedded blocks for
+subtler cases.
+
+ARGV[0] translates to $ARGV0, but ARGV[n] translates to $ARGV[$n-1]. A
+loop that tries to iterate over ARGV[0] won't find it.
+
+=head1 ENVIRONMENT
+
+A2p uses no environment variables.
+
+=head1 AUTHOR
+
+Larry Wall E<lt>F<larry@wall.org>E<gt>
+
+=head1 FILES
+
+=head1 SEE ALSO
+
+ perl The perl compiler/interpreter
+
+ s2p sed to perl translator
+
+=head1 DIAGNOSTICS
+
+=head1 BUGS
+
+It would be possible to emulate awk's behavior in selecting string
+versus numeric operations at run time by inspection of the operands,
+but it would be gross and inefficient. Besides, a2p almost always
+guesses right.
+
+Storage for the awk syntax tree is currently static, and can run out.
diff --git a/Master/tlpkg/tlperl/lib/pods/perl.pod b/Master/tlpkg/tlperl/lib/pods/perl.pod
new file mode 100644
index 00000000000..e67f0627dea
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl.pod
@@ -0,0 +1,462 @@
+=head1 NAME
+
+perl - The Perl language interpreter
+
+=head1 SYNOPSIS
+
+B<perl> S<[ B<-sTtuUWX> ]>
+ S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
+ S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
+ S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
+ S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]>
+ S<[ B<-C [I<number/list>] >]>
+ S<[ B<-S> ]>
+ S<[ B<-x>[I<dir>] ]>
+ S<[ B<-i>[I<extension>] ]>
+ S<[ [B<-e>|B<-E>] I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
+
+=head1 GETTING HELP
+
+The F<perldoc> program gives you access to all the documentation that comes
+with Perl. You can get more documentation, tutorials and community support
+online at L<http://www.perl.org/>.
+
+If you're new to Perl, you should start by running C<perldoc perlintro>,
+which is a general intro for beginners and provides some background to help
+you navigate the rest of Perl's extensive documentation. Run C<perldoc
+perldoc> to learn more things you can do with F<perldoc>.
+
+For ease of access, the Perl manual has been split up into several sections.
+
+=head2 Overview
+
+ perl Perl overview (this section)
+ perlintro Perl introduction for beginners
+ perltoc Perl documentation table of contents
+
+=head2 Tutorials
+
+ perlreftut Perl references short introduction
+ perldsc Perl data structures intro
+ perllol Perl data structures: arrays of arrays
+
+ perlrequick Perl regular expressions quick start
+ perlretut Perl regular expressions tutorial
+
+ perlboot Perl OO tutorial for beginners
+ perltoot Perl OO tutorial, part 1
+ perltooc Perl OO tutorial, part 2
+ perlbot Perl OO tricks and examples
+
+ perlperf Perl Performance and Optimization Techniques
+
+ perlstyle Perl style guide
+
+ perlcheat Perl cheat sheet
+ perltrap Perl traps for the unwary
+ perldebtut Perl debugging tutorial
+
+ perlfaq Perl frequently asked questions
+ perlfaq1 General Questions About Perl
+ perlfaq2 Obtaining and Learning about Perl
+ perlfaq3 Programming Tools
+ perlfaq4 Data Manipulation
+ perlfaq5 Files and Formats
+ perlfaq6 Regexes
+ perlfaq7 Perl Language Issues
+ perlfaq8 System Interaction
+ perlfaq9 Networking
+
+=head2 Reference Manual
+
+ perlsyn Perl syntax
+ perldata Perl data structures
+ perlop Perl operators and precedence
+ perlsub Perl subroutines
+ perlfunc Perl built-in functions
+ perlopentut Perl open() tutorial
+ perlpacktut Perl pack() and unpack() tutorial
+ perlpod Perl plain old documentation
+ perlpodspec Perl plain old documentation format specification
+ perlrun Perl execution and options
+ perldiag Perl diagnostic messages
+ perllexwarn Perl warnings and their control
+ perldebug Perl debugging
+ perlvar Perl predefined variables
+ perlre Perl regular expressions, the rest of the story
+ perlrebackslash Perl regular expression backslash sequences
+ perlrecharclass Perl regular expression character classes
+ perlreref Perl regular expressions quick reference
+ perlref Perl references, the rest of the story
+ perlform Perl formats
+ perlobj Perl objects
+ perltie Perl objects hidden behind simple variables
+ perldbmfilter Perl DBM filters
+
+ perlipc Perl interprocess communication
+ perlfork Perl fork() information
+ perlnumber Perl number semantics
+
+ perlthrtut Perl threads tutorial
+
+ perlport Perl portability guide
+ perllocale Perl locale support
+ perluniintro Perl Unicode introduction
+ perlunicode Perl Unicode support
+ perlunifaq Perl Unicode FAQ
+ perluniprops Index of Unicode Version 5.2.0 properties in Perl
+ perlunitut Perl Unicode tutorial
+ perlebcdic Considerations for running Perl on EBCDIC platforms
+
+ perlsec Perl security
+
+ perlmod Perl modules: how they work
+ perlmodlib Perl modules: how to write and use
+ perlmodstyle Perl modules: how to write modules with style
+ perlmodinstall Perl modules: how to install from CPAN
+ perlnewmod Perl modules: preparing a new module for distribution
+ perlpragma Perl modules: writing a user pragma
+
+ perlutil utilities packaged with the Perl distribution
+
+ perlcompile Perl compiler suite intro
+
+ perlfilter Perl source filters
+
+ perlglossary Perl Glossary
+
+=head2 Internals and C Language Interface
+
+ perlembed Perl ways to embed perl in your C or C++ application
+ perldebguts Perl debugging guts and tips
+ perlxstut Perl XS tutorial
+ perlxs Perl XS application programming interface
+ perlclib Internal replacements for standard C library functions
+ perlguts Perl internal functions for those doing extensions
+ perlcall Perl calling conventions from C
+ perlmroapi Perl method resolution plugin interface
+ perlreapi Perl regular expression plugin interface
+ perlreguts Perl regular expression engine internals
+
+ perlapi Perl API listing (autogenerated)
+ perlintern Perl internal functions (autogenerated)
+ perliol C API for Perl's implementation of IO in Layers
+ perlapio Perl internal IO abstraction interface
+
+ perlhack Perl hackers guide
+ perlpolicy Perl development policies
+ perlrepository Perl source repository
+
+=head2 Miscellaneous
+
+ perlbook Perl book information
+ perlcommunity Perl community information
+ perltodo Perl things to do
+
+ perldoc Look up Perl documentation in Pod format
+
+ perlhist Perl history records
+ perldelta Perl changes since previous version
+ perl5122delta Perl changes in version 5.12.2
+ perl5121delta Perl changes in version 5.12.1
+ perl5120delta Perl changes in version 5.12.0
+ perl5115delta Perl changes in version 5.11.5
+ perl5114delta Perl changes in version 5.11.4
+ perl5113delta Perl changes in version 5.11.3
+ perl5112delta Perl changes in version 5.11.2
+ perl5111delta Perl changes in version 5.11.1
+ perl5110delta Perl changes in version 5.11.0
+ perl5101delta Perl changes in version 5.10.1
+ perl5100delta Perl changes in version 5.10.0
+ perl595delta Perl changes in version 5.9.5
+ perl594delta Perl changes in version 5.9.4
+ perl593delta Perl changes in version 5.9.3
+ perl592delta Perl changes in version 5.9.2
+ perl591delta Perl changes in version 5.9.1
+ perl590delta Perl changes in version 5.9.0
+ perl589delta Perl changes in version 5.8.9
+ perl588delta Perl changes in version 5.8.8
+ perl587delta Perl changes in version 5.8.7
+ perl586delta Perl changes in version 5.8.6
+ perl585delta Perl changes in version 5.8.5
+ perl584delta Perl changes in version 5.8.4
+ perl583delta Perl changes in version 5.8.3
+ perl582delta Perl changes in version 5.8.2
+ perl581delta Perl changes in version 5.8.1
+ perl58delta Perl changes in version 5.8.0
+ perl573delta Perl changes in version 5.7.3
+ perl572delta Perl changes in version 5.7.2
+ perl571delta Perl changes in version 5.7.1
+ perl570delta Perl changes in version 5.7.0
+ perl561delta Perl changes in version 5.6.1
+ perl56delta Perl changes in version 5.6
+ perl5005delta Perl changes in version 5.005
+ perl5004delta Perl changes in version 5.004
+
+ perlartistic Perl Artistic License
+ perlgpl GNU General Public License
+
+=head2 Language-Specific
+
+ perlcn Perl for Simplified Chinese (in EUC-CN)
+ perljp Perl for Japanese (in EUC-JP)
+ perlko Perl for Korean (in EUC-KR)
+ perltw Perl for Traditional Chinese (in Big5)
+
+=head2 Platform-Specific
+
+ perlaix Perl notes for AIX
+ perlamiga Perl notes for AmigaOS
+ perlapollo Perl notes for Apollo DomainOS
+ perlbeos Perl notes for BeOS
+ perlbs2000 Perl notes for POSIX-BC BS2000
+ perlce Perl notes for WinCE
+ perlcygwin Perl notes for Cygwin
+ perldgux Perl notes for DG/UX
+ perldos Perl notes for DOS
+ perlepoc Perl notes for EPOC
+ perlfreebsd Perl notes for FreeBSD
+ perlhaiku Perl notes for Haiku
+ perlhpux Perl notes for HP-UX
+ perlhurd Perl notes for Hurd
+ perlirix Perl notes for Irix
+ perllinux Perl notes for Linux
+ perlmacos Perl notes for Mac OS (Classic)
+ perlmacosx Perl notes for Mac OS X
+ perlmpeix Perl notes for MPE/iX
+ perlnetware Perl notes for NetWare
+ perlopenbsd Perl notes for OpenBSD
+ perlos2 Perl notes for OS/2
+ perlos390 Perl notes for OS/390
+ perlos400 Perl notes for OS/400
+ perlplan9 Perl notes for Plan 9
+ perlqnx Perl notes for QNX
+ perlriscos Perl notes for RISC OS
+ perlsolaris Perl notes for Solaris
+ perlsymbian Perl notes for Symbian
+ perltru64 Perl notes for Tru64
+ perluts Perl notes for UTS
+ perlvmesa Perl notes for VM/ESA
+ perlvms Perl notes for VMS
+ perlvos Perl notes for Stratus VOS
+ perlwin32 Perl notes for Windows
+
+
+On a Unix-like system, these documentation files will usually also be
+available as manpages for use with the F<man> program.
+
+In general, if something strange has gone wrong with your program and you're
+not sure where you should look for help, try the B<-w> switch first. It will
+often point out exactly where the trouble is.
+
+=head1 DESCRIPTION
+
+Perl officially stands for Practical Extraction and Report Language,
+except when it doesn't.
+
+Perl is a language optimized for scanning arbitrary
+text files, extracting information from those text files, and printing
+reports based on that information. It's also a good language for many
+system management tasks. The language is intended to be practical
+(easy to use, efficient, complete) rather than beautiful (tiny,
+elegant, minimal).
+
+Perl combines (in the author's opinion, anyway) some of the best
+features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
+those languages should have little difficulty with it. (Language
+historians will also note some vestiges of B<csh>, Pascal, and even
+BASIC-PLUS.) Expression syntax corresponds closely to C
+expression syntax. Unlike most Unix utilities, Perl does not
+arbitrarily limit the size of your data--if you've got the memory,
+Perl can slurp in your whole file as a single string. Recursion is of
+unlimited depth. And the tables used by hashes (sometimes called
+"associative arrays") grow as necessary to prevent degraded
+performance. Perl can use sophisticated pattern matching techniques to
+scan large amounts of data quickly. Although optimized for
+scanning text, Perl can also deal with binary data, and can make dbm
+files look like hashes. Setuid Perl scripts are safer than C programs
+through a dataflow tracing mechanism that prevents many stupid
+security holes.
+
+If you have a problem that would ordinarily use B<sed> or B<awk> or
+B<sh>, but it exceeds their capabilities or must run a little faster,
+and you don't want to write the silly thing in C, then Perl may be for
+you. There are also translators to turn your B<sed> and B<awk>
+scripts into Perl scripts.
+
+But wait, there's more...
+
+Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
+rewrite that provides the following additional benefits:
+
+=over 4
+
+=item *
+
+modularity and reusability using innumerable modules
+
+Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
+
+=item *
+
+embeddable and extensible
+
+Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
+L<perlguts>, and L<xsubpp>.
+
+=item *
+
+roll-your-own magic variables (including multiple simultaneous DBM
+implementations)
+
+Described in L<perltie> and L<AnyDBM_File>.
+
+=item *
+
+subroutines can now be overridden, autoloaded, and prototyped
+
+Described in L<perlsub>.
+
+=item *
+
+arbitrarily nested data structures and anonymous functions
+
+Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
+
+=item *
+
+object-oriented programming
+
+Described in L<perlobj>, L<perlboot>, L<perltoot>, L<perltooc>,
+and L<perlbot>.
+
+=item *
+
+support for light-weight processes (threads)
+
+Described in L<perlthrtut> and L<threads>.
+
+=item *
+
+support for Unicode, internationalization, and localization
+
+Described in L<perluniintro>, L<perllocale> and L<Locale::Maketext>.
+
+=item *
+
+lexical scoping
+
+Described in L<perlsub>.
+
+=item *
+
+regular expression enhancements
+
+Described in L<perlre>, with additional examples in L<perlop>.
+
+=item *
+
+enhanced debugger and interactive Perl environment,
+with integrated editor support
+
+Described in L<perldebtut>, L<perldebug> and L<perldebguts>.
+
+=item *
+
+POSIX 1003.1 compliant library
+
+Described in L<POSIX>.
+
+=back
+
+Okay, that's I<definitely> enough hype.
+
+=head1 AVAILABILITY
+
+Perl is available for most operating systems, including virtually
+all Unix-like platforms. See L<perlport/"Supported Platforms">
+for a listing.
+
+=head1 ENVIRONMENT
+
+See L<perlrun>.
+
+=head1 AUTHOR
+
+Larry Wall <larry@wall.org>, with the help of oodles of other folks.
+
+If your Perl success stories and testimonials may be of help to others
+who wish to advocate the use of Perl in their applications,
+or if you wish to simply express your gratitude to Larry and the
+Perl developers, please write to perl-thanks@perl.org .
+
+=head1 FILES
+
+ "@INC" locations of perl libraries
+
+=head1 SEE ALSO
+
+ a2p awk to perl translator
+ s2p sed to perl translator
+
+ http://www.perl.org/ the Perl homepage
+ http://www.perl.com/ Perl articles (O'Reilly)
+ http://www.cpan.org/ the Comprehensive Perl Archive
+ http://www.pm.org/ the Perl Mongers
+
+=head1 DIAGNOSTICS
+
+The C<use warnings> pragma (and the B<-w> switch) produces some
+lovely diagnostics.
+
+See L<perldiag> for explanations of all Perl's diagnostics. The C<use
+diagnostics> pragma automatically turns Perl's normally terse warnings
+and errors into these longer forms.
+
+Compilation errors will tell you the line number of the error, with an
+indication of the next token or token type that was to be examined.
+(In a script passed to Perl via B<-e> switches, each
+B<-e> is counted as one line.)
+
+Setuid scripts have additional constraints that can produce error
+messages such as "Insecure dependency". See L<perlsec>.
+
+Did we mention that you should definitely consider using the B<-w>
+switch?
+
+=head1 BUGS
+
+The B<-w> switch is not mandatory.
+
+Perl is at the mercy of your machine's definitions of various
+operations such as type casting, atof(), and floating-point
+output with sprintf().
+
+If your stdio requires a seek or eof between reads and writes on a
+particular stream, so does Perl. (This doesn't apply to sysread()
+and syswrite().)
+
+While none of the built-in data types have any arbitrary size limits
+(apart from memory size), there are still a few arbitrary limits: a
+given variable name may not be longer than 251 characters. Line numbers
+displayed by diagnostics are internally stored as short integers,
+so they are limited to a maximum of 65535 (higher numbers usually being
+affected by wraparound).
+
+You may mail your bug reports (be sure to include full configuration
+information as output by the myconfig program in the perl source
+tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
+in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
+can be used to help mail in a bug report.
+
+Perl actually stands for Pathologically Eclectic Rubbish Lister, but
+don't tell anyone I said that.
+
+=head1 NOTES
+
+The Perl motto is "There's more than one way to do it." Divining
+how many more is left as an exercise to the reader.
+
+The three principal virtues of a programmer are Laziness,
+Impatience, and Hubris. See the Camel Book for why.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5004delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5004delta.pod
new file mode 100644
index 00000000000..c83f3e6afd4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5004delta.pod
@@ -0,0 +1,1612 @@
+=head1 NAME
+
+perl5004delta - what's new for perl5.004
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.003 release (as
+documented in I<Programming Perl>, second edition--the Camel Book) and
+this one.
+
+=head1 Supported Environments
+
+Perl5.004 builds out of the box on Unix, Plan 9, LynxOS, VMS, OS/2,
+QNX, AmigaOS, and Windows NT. Perl runs on Windows 95 as well, but it
+cannot be built there, for lack of a reasonable command interpreter.
+
+=head1 Core Changes
+
+Most importantly, many bugs were fixed, including several security
+problems. See the F<Changes> file in the distribution for details.
+
+=head2 List assignment to %ENV works
+
+C<%ENV = ()> and C<%ENV = @list> now work as expected (except on VMS
+where it generates a fatal error).
+
+=head2 Change to "Can't locate Foo.pm in @INC" error
+
+The error "Can't locate Foo.pm in @INC" now lists the contents of @INC
+for easier debugging.
+
+=head2 Compilation option: Binary compatibility with 5.003
+
+There is a new Configure question that asks if you want to maintain
+binary compatibility with Perl 5.003. If you choose binary
+compatibility, you do not have to recompile your extensions, but you
+might have symbol conflicts if you embed Perl in another application,
+just as in the 5.003 release. By default, binary compatibility
+is preserved at the expense of symbol table pollution.
+
+=head2 $PERL5OPT environment variable
+
+You may now put Perl options in the $PERL5OPT environment variable.
+Unless Perl is running with taint checks, it will interpret this
+variable as if its contents had appeared on a "#!perl" line at the
+beginning of your script, except that hyphens are optional. PERL5OPT
+may only be used to set the following switches: B<-[DIMUdmw]>.
+
+=head2 Limitations on B<-M>, B<-m>, and B<-T> options
+
+The C<-M> and C<-m> options are no longer allowed on the C<#!> line of
+a script. If a script needs a module, it should invoke it with the
+C<use> pragma.
+
+The B<-T> option is also forbidden on the C<#!> line of a script,
+unless it was present on the Perl command line. Due to the way C<#!>
+works, this usually means that B<-T> must be in the first argument.
+Thus:
+
+ #!/usr/bin/perl -T -w
+
+will probably work for an executable script invoked as C<scriptname>,
+while:
+
+ #!/usr/bin/perl -w -T
+
+will probably fail under the same conditions. (Non-Unix systems will
+probably not follow this rule.) But C<perl scriptname> is guaranteed
+to fail, since then there is no chance of B<-T> being found on the
+command line before it is found on the C<#!> line.
+
+=head2 More precise warnings
+
+If you removed the B<-w> option from your Perl 5.003 scripts because it
+made Perl too verbose, we recommend that you try putting it back when
+you upgrade to Perl 5.004. Each new perl version tends to remove some
+undesirable warnings, while adding new warnings that may catch bugs in
+your scripts.
+
+=head2 Deprecated: Inherited C<AUTOLOAD> for non-methods
+
+Before Perl 5.004, C<AUTOLOAD> functions were looked up as methods
+(using the C<@ISA> hierarchy), even when the function to be autoloaded
+was called as a plain function (e.g. C<Foo::bar()>), not a method
+(e.g. C<< Foo->bar() >> or C<< $obj->bar() >>).
+
+Perl 5.005 will use method lookup only for methods' C<AUTOLOAD>s.
+However, there is a significant base of existing code that may be using
+the old behavior. So, as an interim step, Perl 5.004 issues an optional
+warning when a non-method uses an inherited C<AUTOLOAD>.
+
+The simple rule is: Inheritance will not work when autoloading
+non-methods. The simple fix for old code is: In any module that used to
+depend on inheriting C<AUTOLOAD> for non-methods from a base class named
+C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during startup.
+
+=head2 Previously deprecated %OVERLOAD is no longer usable
+
+Using %OVERLOAD to define overloading was deprecated in 5.003.
+Overloading is now defined using the overload pragma. %OVERLOAD is
+still used internally but should not be used by Perl scripts. See
+L<overload> for more details.
+
+=head2 Subroutine arguments created only when they're modified
+
+In Perl 5.004, nonexistent array and hash elements used as subroutine
+parameters are brought into existence only if they are actually
+assigned to (via C<@_>).
+
+Earlier versions of Perl vary in their handling of such arguments.
+Perl versions 5.002 and 5.003 always brought them into existence.
+Perl versions 5.000 and 5.001 brought them into existence only if
+they were not the first argument (which was almost certainly a bug).
+Earlier versions of Perl never brought them into existence.
+
+For example, given this code:
+
+ undef @a; undef %a;
+ sub show { print $_[0] };
+ sub change { $_[0]++ };
+ show($a[2]);
+ change($a{b});
+
+After this code executes in Perl 5.004, $a{b} exists but $a[2] does
+not. In Perl 5.002 and 5.003, both $a{b} and $a[2] would have existed
+(but $a[2]'s value would have been undefined).
+
+=head2 Group vector changeable with C<$)>
+
+The C<$)> special variable has always (well, in Perl 5, at least)
+reflected not only the current effective group, but also the group list
+as returned by the C<getgroups()> C function (if there is one).
+However, until this release, there has not been a way to call the
+C<setgroups()> C function from Perl.
+
+In Perl 5.004, assigning to C<$)> is exactly symmetrical with examining
+it: The first number in its string value is used as the effective gid;
+if there are any numbers after the first one, they are passed to the
+C<setgroups()> C function (if there is one).
+
+=head2 Fixed parsing of $$<digit>, &$<digit>, etc.
+
+Perl versions before 5.004 misinterpreted any type marker followed by
+"$" and a digit. For example, "$$0" was incorrectly taken to mean
+"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
+
+However, the developers of Perl 5.004 could not fix this bug completely,
+because at least two widely-used modules depend on the old meaning of
+"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
+old (broken) way inside strings; but it generates this message as a
+warning. And in Perl 5.005, this special treatment will cease.
+
+=head2 Fixed localization of $<digit>, $&, etc.
+
+Perl versions before 5.004 did not always properly localize the
+regex-related special variables. Perl 5.004 does localize them, as
+the documentation has always said it should. This may result in $1,
+$2, etc. no longer being set where existing programs use them.
+
+=head2 No resetting of $. on implicit close
+
+The documentation for Perl 5.0 has always stated that C<$.> is I<not>
+reset when an already-open file handle is reopened with no intervening
+call to C<close>. Due to a bug, perl versions 5.000 through 5.003
+I<did> reset C<$.> under that circumstance; Perl 5.004 does not.
+
+=head2 C<wantarray> may return undef
+
+The C<wantarray> operator returns true if a subroutine is expected to
+return a list, and false otherwise. In Perl 5.004, C<wantarray> can
+also return the undefined value if a subroutine's return value will
+not be used at all, which allows subroutines to avoid a time-consuming
+calculation of a return value if it isn't going to be used.
+
+=head2 C<eval EXPR> determines value of EXPR in scalar context
+
+Perl (version 5) used to determine the value of EXPR inconsistently,
+sometimes incorrectly using the surrounding context for the determination.
+Now, the value of EXPR (before being parsed by eval) is always determined in
+a scalar context. Once parsed, it is executed as before, by providing
+the context that the scope surrounding the eval provided. This change
+makes the behavior Perl4 compatible, besides fixing bugs resulting from
+the inconsistent behavior. This program:
+
+ @a = qw(time now is time);
+ print eval @a;
+ print '|', scalar eval @a;
+
+used to print something like "timenowis881399109|4", but now (and in perl4)
+prints "4|4".
+
+=head2 Changes to tainting checks
+
+A bug in previous versions may have failed to detect some insecure
+conditions when taint checks are turned on. (Taint checks are used
+in setuid or setgid scripts, or when explicitly turned on with the
+C<-T> invocation option.) Although it's unlikely, this may cause a
+previously-working script to now fail, which should be construed
+as a blessing since that indicates a potentially-serious security
+hole was just plugged.
+
+The new restrictions when tainting include:
+
+=over 4
+
+=item No glob() or <*>
+
+These operators may spawn the C shell (csh), which cannot be made
+safe. This restriction will be lifted in a future version of Perl
+when globbing is implemented without the use of an external program.
+
+=item No spawning if tainted $CDPATH, $ENV, $BASH_ENV
+
+These environment variables may alter the behavior of spawned programs
+(especially shells) in ways that subvert security. So now they are
+treated as dangerous, in the manner of $IFS and $PATH.
+
+=item No spawning if tainted $TERM doesn't look like a terminal name
+
+Some termcap libraries do unsafe things with $TERM. However, it would be
+unnecessarily harsh to treat all $TERM values as unsafe, since only shell
+metacharacters can cause trouble in $TERM. So a tainted $TERM is
+considered to be safe if it contains only alphanumerics, underscores,
+dashes, and colons, and unsafe if it contains other characters (including
+whitespace).
+
+=back
+
+=head2 New Opcode module and revised Safe module
+
+A new Opcode module supports the creation, manipulation and
+application of opcode masks. The revised Safe module has a new API
+and is implemented using the new Opcode module. Please read the new
+Opcode and Safe documentation.
+
+=head2 Embedding improvements
+
+In older versions of Perl it was not possible to create more than one
+Perl interpreter instance inside a single process without leaking like a
+sieve and/or crashing. The bugs that caused this behavior have all been
+fixed. However, you still must take care when embedding Perl in a C
+program. See the updated perlembed manpage for tips on how to manage
+your interpreters.
+
+=head2 Internal change: FileHandle class based on IO::* classes
+
+File handles are now stored internally as type IO::Handle. The
+FileHandle module is still supported for backwards compatibility, but
+it is now merely a front end to the IO::* modules, specifically
+IO::Handle, IO::Seekable, and IO::File. We suggest, but do not
+require, that you use the IO::* modules in new code.
+
+In harmony with this change, C<*GLOB{FILEHANDLE}> is now just a
+backward-compatible synonym for C<*GLOB{IO}>.
+
+=head2 Internal change: PerlIO abstraction interface
+
+It is now possible to build Perl with AT&T's sfio IO package
+instead of stdio. See L<perlapio> for more details, and
+the F<INSTALL> file for how to use it.
+
+=head2 New and changed syntax
+
+=over 4
+
+=item $coderef->(PARAMS)
+
+A subroutine reference may now be suffixed with an arrow and a
+(possibly empty) parameter list. This syntax denotes a call of the
+referenced subroutine, with the given parameters (if any).
+
+This new syntax follows the pattern of S<C<< $hashref->{FOO} >>> and
+S<C<< $aryref->[$foo] >>>: You may now write S<C<&$subref($foo)>> as
+S<C<< $subref->($foo) >>>. All these arrow terms may be chained;
+thus, S<C<< &{$table->{FOO}}($bar) >>> may now be written
+S<C<< $table->{FOO}->($bar) >>>.
+
+=back
+
+=head2 New and changed builtin constants
+
+=over 4
+
+=item __PACKAGE__
+
+The current package name at compile time, or the undefined value if
+there is no current package (due to a C<package;> directive). Like
+C<__FILE__> and C<__LINE__>, C<__PACKAGE__> does I<not> interpolate
+into strings.
+
+=back
+
+=head2 New and changed builtin variables
+
+=over 4
+
+=item $^E
+
+Extended error message on some platforms. (Also known as
+$EXTENDED_OS_ERROR if you C<use English>).
+
+=item $^H
+
+The current set of syntax checks enabled by C<use strict>. See the
+documentation of C<strict> for more details. Not actually new, but
+newly documented.
+Because it is intended for internal use by Perl core components,
+there is no C<use English> long name for this variable.
+
+=item $^M
+
+By default, running out of memory it is not trappable. However, if
+compiled for this, Perl may use the contents of C<$^M> as an emergency
+pool after die()ing with this message. Suppose that your Perl were
+compiled with -DPERL_EMERGENCY_SBRK and used Perl's malloc. Then
+
+ $^M = 'a' x (1<<16);
+
+would allocate a 64K buffer for use when in emergency.
+See the F<INSTALL> file for information on how to enable this option.
+As a disincentive to casual use of this advanced feature,
+there is no C<use English> long name for this variable.
+
+=back
+
+=head2 New and changed builtin functions
+
+=over 4
+
+=item delete on slices
+
+This now works. (e.g. C<delete @ENV{'PATH', 'MANPATH'}>)
+
+=item flock
+
+is now supported on more platforms, prefers fcntl to lockf when
+emulating, and always flushes before (un)locking.
+
+=item printf and sprintf
+
+Perl now implements these functions itself; it doesn't use the C
+library function sprintf() any more, except for floating-point
+numbers, and even then only known flags are allowed. As a result, it
+is now possible to know which conversions and flags will work, and
+what they will do.
+
+The new conversions in Perl's sprintf() are:
+
+ %i a synonym for %d
+ %p a pointer (the address of the Perl value, in hexadecimal)
+ %n special: *stores* the number of characters output so far
+ into the next variable in the parameter list
+
+The new flags that go between the C<%> and the conversion are:
+
+ # prefix octal with "0", hex with "0x"
+ h interpret integer as C type "short" or "unsigned short"
+ V interpret integer as Perl's standard integer type
+
+Also, where a number would appear in the flags, an asterisk ("*") may
+be used instead, in which case Perl uses the next item in the
+parameter list as the given number (that is, as the field width or
+precision). If a field width obtained through "*" is negative, it has
+the same effect as the '-' flag: left-justification.
+
+See L<perlfunc/sprintf> for a complete list of conversion and flags.
+
+=item keys as an lvalue
+
+As an lvalue, C<keys> allows you to increase the number of hash buckets
+allocated for the given hash. This can gain you a measure of efficiency if
+you know the hash is going to get big. (This is similar to pre-extending
+an array by assigning a larger number to $#array.) If you say
+
+ keys %hash = 200;
+
+then C<%hash> will have at least 200 buckets allocated for it. These
+buckets will be retained even if you do C<%hash = ()>; use C<undef
+%hash> if you want to free the storage while C<%hash> is still in scope.
+You can't shrink the number of buckets allocated for the hash using
+C<keys> in this way (but you needn't worry about doing this by accident,
+as trying has no effect).
+
+=item my() in Control Structures
+
+You can now use my() (with or without the parentheses) in the control
+expressions of control structures such as:
+
+ while (defined(my $line = <>)) {
+ $line = lc $line;
+ } continue {
+ print $line;
+ }
+
+ if ((my $answer = <STDIN>) =~ /^y(es)?$/i) {
+ user_agrees();
+ } elsif ($answer =~ /^n(o)?$/i) {
+ user_disagrees();
+ } else {
+ chomp $answer;
+ die "`$answer' is neither `yes' nor `no'";
+ }
+
+Also, you can declare a foreach loop control variable as lexical by
+preceding it with the word "my". For example, in:
+
+ foreach my $i (1, 2, 3) {
+ some_function();
+ }
+
+$i is a lexical variable, and the scope of $i extends to the end of
+the loop, but not beyond it.
+
+Note that you still cannot use my() on global punctuation variables
+such as $_ and the like.
+
+=item pack() and unpack()
+
+A new format 'w' represents a BER compressed integer (as defined in
+ASN.1). Its format is a sequence of one or more bytes, each of which
+provides seven bits of the total value, with the most significant
+first. Bit eight of each byte is set, except for the last byte, in
+which bit eight is clear.
+
+If 'p' or 'P' are given undef as values, they now generate a NULL
+pointer.
+
+Both pack() and unpack() now fail when their templates contain invalid
+types. (Invalid types used to be ignored.)
+
+=item sysseek()
+
+The new sysseek() operator is a variant of seek() that sets and gets the
+file's system read/write position, using the lseek(2) system call. It is
+the only reliable way to seek before using sysread() or syswrite(). Its
+return value is the new position, or the undefined value on failure.
+
+=item use VERSION
+
+If the first argument to C<use> is a number, it is treated as a version
+number instead of a module name. If the version of the Perl interpreter
+is less than VERSION, then an error message is printed and Perl exits
+immediately. Because C<use> occurs at compile time, this check happens
+immediately during the compilation process, unlike C<require VERSION>,
+which waits until runtime for the check. This is often useful if you
+need to check the current Perl version before C<use>ing library modules
+which have changed in incompatible ways from older versions of Perl.
+(We try not to do this more than we have to.)
+
+=item use Module VERSION LIST
+
+If the VERSION argument is present between Module and LIST, then the
+C<use> will call the VERSION method in class Module with the given
+version as an argument. The default VERSION method, inherited from
+the UNIVERSAL class, croaks if the given version is larger than the
+value of the variable $Module::VERSION. (Note that there is not a
+comma after VERSION!)
+
+This version-checking mechanism is similar to the one currently used
+in the Exporter module, but it is faster and can be used with modules
+that don't use the Exporter. It is the recommended method for new
+code.
+
+=item prototype(FUNCTION)
+
+Returns the prototype of a function as a string (or C<undef> if the
+function has no prototype). FUNCTION is a reference to or the name of the
+function whose prototype you want to retrieve.
+(Not actually new; just never documented before.)
+
+=item srand
+
+The default seed for C<srand>, which used to be C<time>, has been changed.
+Now it's a heady mix of difficult-to-predict system-dependent values,
+which should be sufficient for most everyday purposes.
+
+Previous to version 5.004, calling C<rand> without first calling C<srand>
+would yield the same sequence of random numbers on most or all machines.
+Now, when perl sees that you're calling C<rand> and haven't yet called
+C<srand>, it calls C<srand> with the default seed. You should still call
+C<srand> manually if your code might ever be run on a pre-5.004 system,
+of course, or if you want a seed other than the default.
+
+=item $_ as Default
+
+Functions documented in the Camel to default to $_ now in
+fact do, and all those that do are so documented in L<perlfunc>.
+
+=item C<m//gc> does not reset search position on failure
+
+The C<m//g> match iteration construct has always reset its target
+string's search position (which is visible through the C<pos> operator)
+when a match fails; as a result, the next C<m//g> match after a failure
+starts again at the beginning of the string. With Perl 5.004, this
+reset may be disabled by adding the "c" (for "continue") modifier,
+i.e. C<m//gc>. This feature, in conjunction with the C<\G> zero-width
+assertion, makes it possible to chain matches together. See L<perlop>
+and L<perlre>.
+
+=item C<m//x> ignores whitespace before ?*+{}
+
+The C<m//x> construct has always been intended to ignore all unescaped
+whitespace. However, before Perl 5.004, whitespace had the effect of
+escaping repeat modifiers like "*" or "?"; for example, C</a *b/x> was
+(mis)interpreted as C</a\*b/x>. This bug has been fixed in 5.004.
+
+=item nested C<sub{}> closures work now
+
+Prior to the 5.004 release, nested anonymous functions didn't work
+right. They do now.
+
+=item formats work right on changing lexicals
+
+Just like anonymous functions that contain lexical variables
+that change (like a lexical index variable for a C<foreach> loop),
+formats now work properly. For example, this silently failed
+before (printed only zeros), but is fine now:
+
+ my $i;
+ foreach $i ( 1 .. 10 ) {
+ write;
+ }
+ format =
+ my i is @#
+ $i
+ .
+
+However, it still fails (without a warning) if the foreach is within a
+subroutine:
+
+ my $i;
+ sub foo {
+ foreach $i ( 1 .. 10 ) {
+ write;
+ }
+ }
+ foo;
+ format =
+ my i is @#
+ $i
+ .
+
+=back
+
+=head2 New builtin methods
+
+The C<UNIVERSAL> package automatically contains the following methods that
+are inherited by all other classes:
+
+=over 4
+
+=item isa(CLASS)
+
+C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS>
+
+C<isa> is also exportable and can be called as a sub with two arguments. This
+allows the ability to check what a reference points to. Example:
+
+ use UNIVERSAL qw(isa);
+
+ if(isa($ref, 'ARRAY')) {
+ ...
+ }
+
+=item can(METHOD)
+
+C<can> checks to see if its object has a method called C<METHOD>,
+if it does then a reference to the sub is returned; if it does not then
+I<undef> is returned.
+
+=item VERSION( [NEED] )
+
+C<VERSION> returns the version number of the class (package). If the
+NEED argument is given then it will check that the current version (as
+defined by the $VERSION variable in the given package) not less than
+NEED; it will die if this is not the case. This method is normally
+called as a class method. This method is called automatically by the
+C<VERSION> form of C<use>.
+
+ use A 1.2 qw(some imported subs);
+ # implies:
+ A->VERSION(1.2);
+
+=back
+
+B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and
+C<isa> uses a very similar method and caching strategy. This may cause
+strange effects if the Perl code dynamically changes @ISA in any package.
+
+You may add other methods to the UNIVERSAL class via Perl or XS code.
+You do not need to C<use UNIVERSAL> in order to make these methods
+available to your program. This is necessary only if you wish to
+have C<isa> available as a plain subroutine in the current package.
+
+=head2 TIEHANDLE now supported
+
+See L<perltie> for other kinds of tie()s.
+
+=over 4
+
+=item TIEHANDLE classname, LIST
+
+This is the constructor for the class. That means it is expected to
+return an object of some sort. The reference can be used to
+hold some internal information.
+
+ sub TIEHANDLE {
+ print "<shout>\n";
+ my $i;
+ return bless \$i, shift;
+ }
+
+=item PRINT this, LIST
+
+This method will be triggered every time the tied handle is printed to.
+Beyond its self reference it also expects the list that was passed to
+the print function.
+
+ sub PRINT {
+ $r = shift;
+ $$r++;
+ return print join( $, => map {uc} @_), $\;
+ }
+
+=item PRINTF this, LIST
+
+This method will be triggered every time the tied handle is printed to
+with the C<printf()> function.
+Beyond its self reference it also expects the format and list that was
+passed to the printf function.
+
+ sub PRINTF {
+ shift;
+ my $fmt = shift;
+ print sprintf($fmt, @_)."\n";
+ }
+
+=item READ this LIST
+
+This method will be called when the handle is read from via the C<read>
+or C<sysread> functions.
+
+ sub READ {
+ $r = shift;
+ my($buf,$len,$offset) = @_;
+ print "READ called, \$buf=$buf, \$len=$len, \$offset=$offset";
+ }
+
+=item READLINE this
+
+This method will be called when the handle is read from. The method
+should return undef when there is no more data.
+
+ sub READLINE {
+ $r = shift;
+ return "PRINT called $$r times\n"
+ }
+
+=item GETC this
+
+This method will be called when the C<getc> function is called.
+
+ sub GETC { print "Don't GETC, Get Perl"; return "a"; }
+
+=item DESTROY this
+
+As with the other types of ties, this method will be called when the
+tied handle is about to be destroyed. This is useful for debugging and
+possibly for cleaning up.
+
+ sub DESTROY {
+ print "</shout>\n";
+ }
+
+=back
+
+=head2 Malloc enhancements
+
+If perl is compiled with the malloc included with the perl distribution
+(that is, if C<perl -V:d_mymalloc> is 'define') then you can print
+memory statistics at runtime by running Perl thusly:
+
+ env PERL_DEBUG_MSTATS=2 perl your_script_here
+
+The value of 2 means to print statistics after compilation and on
+exit; with a value of 1, the statistics are printed only on exit.
+(If you want the statistics at an arbitrary time, you'll need to
+install the optional module Devel::Peek.)
+
+Three new compilation flags are recognized by malloc.c. (They have no
+effect if perl is compiled with system malloc().)
+
+=over 4
+
+=item -DPERL_EMERGENCY_SBRK
+
+If this macro is defined, running out of memory need not be a fatal
+error: a memory pool can allocated by assigning to the special
+variable C<$^M>. See L<"$^M">.
+
+=item -DPACK_MALLOC
+
+Perl memory allocation is by bucket with sizes close to powers of two.
+Because of these malloc overhead may be big, especially for data of
+size exactly a power of two. If C<PACK_MALLOC> is defined, perl uses
+a slightly different algorithm for small allocations (up to 64 bytes
+long), which makes it possible to have overhead down to 1 byte for
+allocations which are powers of two (and appear quite often).
+
+Expected memory savings (with 8-byte alignment in C<alignbytes>) is
+about 20% for typical Perl usage. Expected slowdown due to additional
+malloc overhead is in fractions of a percent (hard to measure, because
+of the effect of saved memory on speed).
+
+=item -DTWO_POT_OPTIMIZE
+
+Similarly to C<PACK_MALLOC>, this macro improves allocations of data
+with size close to a power of two; but this works for big allocations
+(starting with 16K by default). Such allocations are typical for big
+hashes and special-purpose scripts, especially image processing.
+
+On recent systems, the fact that perl requires 2M from system for 1M
+allocation will not affect speed of execution, since the tail of such
+a chunk is not going to be touched (and thus will not require real
+memory). However, it may result in a premature out-of-memory error.
+So if you will be manipulating very large blocks with sizes close to
+powers of two, it would be wise to define this macro.
+
+Expected saving of memory is 0-100% (100% in applications which
+require most memory in such 2**n chunks); expected slowdown is
+negligible.
+
+=back
+
+=head2 Miscellaneous efficiency enhancements
+
+Functions that have an empty prototype and that do nothing but return
+a fixed value are now inlined (e.g. C<sub PI () { 3.14159 }>).
+
+Each unique hash key is only allocated once, no matter how many hashes
+have an entry with that key. So even if you have 100 copies of the
+same hash, the hash keys never have to be reallocated.
+
+=head1 Support for More Operating Systems
+
+Support for the following operating systems is new in Perl 5.004.
+
+=head2 Win32
+
+Perl 5.004 now includes support for building a "native" perl under
+Windows NT, using the Microsoft Visual C++ compiler (versions 2.0
+and above) or the Borland C++ compiler (versions 5.02 and above).
+The resulting perl can be used under Windows 95 (if it
+is installed in the same directory locations as it got installed
+in Windows NT). This port includes support for perl extension
+building tools like L<MakeMaker> and L<h2xs>, so that many extensions
+available on the Comprehensive Perl Archive Network (CPAN) can now be
+readily built under Windows NT. See http://www.perl.com/ for more
+information on CPAN and F<README.win32> in the perl distribution for more
+details on how to get started with building this port.
+
+There is also support for building perl under the Cygwin32 environment.
+Cygwin32 is a set of GNU tools that make it possible to compile and run
+many Unix programs under Windows NT by providing a mostly Unix-like
+interface for compilation and execution. See F<README.cygwin32> in the
+perl distribution for more details on this port and how to obtain the
+Cygwin32 toolkit.
+
+=head2 Plan 9
+
+See F<README.plan9> in the perl distribution.
+
+=head2 QNX
+
+See F<README.qnx> in the perl distribution.
+
+=head2 AmigaOS
+
+See F<README.amigaos> in the perl distribution.
+
+=head1 Pragmata
+
+Six new pragmatic modules exist:
+
+=over 4
+
+=item use autouse MODULE => qw(sub1 sub2 sub3)
+
+Defers C<require MODULE> until someone calls one of the specified
+subroutines (which must be exported by MODULE). This pragma should be
+used with caution, and only when necessary.
+
+=item use blib
+
+=item use blib 'dir'
+
+Looks for MakeMaker-like I<'blib'> directory structure starting in
+I<dir> (or current directory) and working back up to five levels of
+parent directories.
+
+Intended for use on command line with B<-M> option as a way of testing
+arbitrary scripts against an uninstalled version of a package.
+
+=item use constant NAME => VALUE
+
+Provides a convenient interface for creating compile-time constants,
+See L<perlsub/"Constant Functions">.
+
+=item use locale
+
+Tells the compiler to enable (or disable) the use of POSIX locales for
+builtin operations.
+
+When C<use locale> is in effect, the current LC_CTYPE locale is used
+for regular expressions and case mapping; LC_COLLATE for string
+ordering; and LC_NUMERIC for numeric formatting in printf and sprintf
+(but B<not> in print). LC_NUMERIC is always used in write, since
+lexical scoping of formats is problematic at best.
+
+Each C<use locale> or C<no locale> affects statements to the end of
+the enclosing BLOCK or, if not inside a BLOCK, to the end of the
+current file. Locales can be switched and queried with
+POSIX::setlocale().
+
+See L<perllocale> for more information.
+
+=item use ops
+
+Disable unsafe opcodes, or any named opcodes, when compiling Perl code.
+
+=item use vmsish
+
+Enable VMS-specific language features. Currently, there are three
+VMS-specific features available: 'status', which makes C<$?> and
+C<system> return genuine VMS status values instead of emulating POSIX;
+'exit', which makes C<exit> take a genuine VMS status value instead of
+assuming that C<exit 1> is an error; and 'time', which makes all times
+relative to the local time zone, in the VMS tradition.
+
+=back
+
+=head1 Modules
+
+=head2 Required Updates
+
+Though Perl 5.004 is compatible with almost all modules that work
+with Perl 5.003, there are a few exceptions:
+
+ Module Required Version for Perl 5.004
+ ------ -------------------------------
+ Filter Filter-1.12
+ LWP libwww-perl-5.08
+ Tk Tk400.202 (-w makes noise)
+
+Also, the majordomo mailing list program, version 1.94.1, doesn't work
+with Perl 5.004 (nor with perl 4), because it executes an invalid
+regular expression. This bug is fixed in majordomo version 1.94.2.
+
+=head2 Installation directories
+
+The I<installperl> script now places the Perl source files for
+extensions in the architecture-specific library directory, which is
+where the shared libraries for extensions have always been. This
+change is intended to allow administrators to keep the Perl 5.004
+library directory unchanged from a previous version, without running
+the risk of binary incompatibility between extensions' Perl source and
+shared libraries.
+
+=head2 Module information summary
+
+Brand new modules, arranged by topic rather than strictly
+alphabetically:
+
+ CGI.pm Web server interface ("Common Gateway Interface")
+ CGI/Apache.pm Support for Apache's Perl module
+ CGI/Carp.pm Log server errors with helpful context
+ CGI/Fast.pm Support for FastCGI (persistent server process)
+ CGI/Push.pm Support for server push
+ CGI/Switch.pm Simple interface for multiple server types
+
+ CPAN Interface to Comprehensive Perl Archive Network
+ CPAN::FirstTime Utility for creating CPAN configuration file
+ CPAN::Nox Runs CPAN while avoiding compiled extensions
+
+ IO.pm Top-level interface to IO::* classes
+ IO/File.pm IO::File extension Perl module
+ IO/Handle.pm IO::Handle extension Perl module
+ IO/Pipe.pm IO::Pipe extension Perl module
+ IO/Seekable.pm IO::Seekable extension Perl module
+ IO/Select.pm IO::Select extension Perl module
+ IO/Socket.pm IO::Socket extension Perl module
+
+ Opcode.pm Disable named opcodes when compiling Perl code
+
+ ExtUtils/Embed.pm Utilities for embedding Perl in C programs
+ ExtUtils/testlib.pm Fixes up @INC to use just-built extension
+
+ FindBin.pm Find path of currently executing program
+
+ Class/Struct.pm Declare struct-like datatypes as Perl classes
+ File/stat.pm By-name interface to Perl's builtin stat
+ Net/hostent.pm By-name interface to Perl's builtin gethost*
+ Net/netent.pm By-name interface to Perl's builtin getnet*
+ Net/protoent.pm By-name interface to Perl's builtin getproto*
+ Net/servent.pm By-name interface to Perl's builtin getserv*
+ Time/gmtime.pm By-name interface to Perl's builtin gmtime
+ Time/localtime.pm By-name interface to Perl's builtin localtime
+ Time/tm.pm Internal object for Time::{gm,local}time
+ User/grent.pm By-name interface to Perl's builtin getgr*
+ User/pwent.pm By-name interface to Perl's builtin getpw*
+
+ Tie/RefHash.pm Base class for tied hashes with references as keys
+
+ UNIVERSAL.pm Base class for *ALL* classes
+
+=head2 Fcntl
+
+New constants in the existing Fcntl modules are now supported,
+provided that your operating system happens to support them:
+
+ F_GETOWN F_SETOWN
+ O_ASYNC O_DEFER O_DSYNC O_FSYNC O_SYNC
+ O_EXLOCK O_SHLOCK
+
+These constants are intended for use with the Perl operators sysopen()
+and fcntl() and the basic database modules like SDBM_File. For the
+exact meaning of these and other Fcntl constants please refer to your
+operating system's documentation for fcntl() and open().
+
+In addition, the Fcntl module now provides these constants for use
+with the Perl operator flock():
+
+ LOCK_SH LOCK_EX LOCK_NB LOCK_UN
+
+These constants are defined in all environments (because where there is
+no flock() system call, Perl emulates it). However, for historical
+reasons, these constants are not exported unless they are explicitly
+requested with the ":flock" tag (e.g. C<use Fcntl ':flock'>).
+
+=head2 IO
+
+The IO module provides a simple mechanism to load all the IO modules at one
+go. Currently this includes:
+
+ IO::Handle
+ IO::Seekable
+ IO::File
+ IO::Pipe
+ IO::Socket
+
+For more information on any of these modules, please see its
+respective documentation.
+
+=head2 Math::Complex
+
+The Math::Complex module has been totally rewritten, and now supports
+more operations. These are overloaded:
+
+ + - * / ** <=> neg ~ abs sqrt exp log sin cos atan2 "" (stringify)
+
+And these functions are now exported:
+
+ pi i Re Im arg
+ log10 logn ln cbrt root
+ tan
+ csc sec cot
+ asin acos atan
+ acsc asec acot
+ sinh cosh tanh
+ csch sech coth
+ asinh acosh atanh
+ acsch asech acoth
+ cplx cplxe
+
+=head2 Math::Trig
+
+This new module provides a simpler interface to parts of Math::Complex for
+those who need trigonometric functions only for real numbers.
+
+=head2 DB_File
+
+There have been quite a few changes made to DB_File. Here are a few of
+the highlights:
+
+=over 4
+
+=item *
+
+Fixed a handful of bugs.
+
+=item *
+
+By public demand, added support for the standard hash function exists().
+
+=item *
+
+Made it compatible with Berkeley DB 1.86.
+
+=item *
+
+Made negative subscripts work with RECNO interface.
+
+=item *
+
+Changed the default flags from O_RDWR to O_CREAT|O_RDWR and the default
+mode from 0640 to 0666.
+
+=item *
+
+Made DB_File automatically import the open() constants (O_RDWR,
+O_CREAT etc.) from Fcntl, if available.
+
+=item *
+
+Updated documentation.
+
+=back
+
+Refer to the HISTORY section in DB_File.pm for a complete list of
+changes. Everything after DB_File 1.01 has been added since 5.003.
+
+=head2 Net::Ping
+
+Major rewrite - support added for both udp echo and real icmp pings.
+
+=head2 Object-oriented overrides for builtin operators
+
+Many of the Perl builtins returning lists now have
+object-oriented overrides. These are:
+
+ File::stat
+ Net::hostent
+ Net::netent
+ Net::protoent
+ Net::servent
+ Time::gmtime
+ Time::localtime
+ User::grent
+ User::pwent
+
+For example, you can now say
+
+ use File::stat;
+ use User::pwent;
+ $his = (stat($filename)->st_uid == pwent($whoever)->pw_uid);
+
+=head1 Utility Changes
+
+=head2 pod2html
+
+=over 4
+
+=item Sends converted HTML to standard output
+
+The I<pod2html> utility included with Perl 5.004 is entirely new.
+By default, it sends the converted HTML to its standard output,
+instead of writing it to a file like Perl 5.003's I<pod2html> did.
+Use the B<--outfile=FILENAME> option to write to a file.
+
+=back
+
+=head2 xsubpp
+
+=over 4
+
+=item C<void> XSUBs now default to returning nothing
+
+Due to a documentation/implementation bug in previous versions of
+Perl, XSUBs with a return type of C<void> have actually been
+returning one value. Usually that value was the GV for the XSUB,
+but sometimes it was some already freed or reused value, which would
+sometimes lead to program failure.
+
+In Perl 5.004, if an XSUB is declared as returning C<void>, it
+actually returns no value, i.e. an empty list (though there is a
+backward-compatibility exception; see below). If your XSUB really
+does return an SV, you should give it a return type of C<SV *>.
+
+For backward compatibility, I<xsubpp> tries to guess whether a
+C<void> XSUB is really C<void> or if it wants to return an C<SV *>.
+It does so by examining the text of the XSUB: if I<xsubpp> finds
+what looks like an assignment to C<ST(0)>, it assumes that the
+XSUB's return type is really C<SV *>.
+
+=back
+
+=head1 C Language API Changes
+
+=over 4
+
+=item C<gv_fetchmethod> and C<perl_call_sv>
+
+The C<gv_fetchmethod> function finds a method for an object, just like
+in Perl 5.003. The GV it returns may be a method cache entry.
+However, in Perl 5.004, method cache entries are not visible to users;
+therefore, they can no longer be passed directly to C<perl_call_sv>.
+Instead, you should use the C<GvCV> macro on the GV to extract its CV,
+and pass the CV to C<perl_call_sv>.
+
+The most likely symptom of passing the result of C<gv_fetchmethod> to
+C<perl_call_sv> is Perl's producing an "Undefined subroutine called"
+error on the I<second> call to a given method (since there is no cache
+on the first call).
+
+=item C<perl_eval_pv>
+
+A new function handy for eval'ing strings of Perl code inside C code.
+This function returns the value from the eval statement, which can
+be used instead of fetching globals from the symbol table. See
+L<perlguts>, L<perlembed> and L<perlcall> for details and examples.
+
+=item Extended API for manipulating hashes
+
+Internal handling of hash keys has changed. The old hashtable API is
+still fully supported, and will likely remain so. The additions to the
+API allow passing keys as C<SV*>s, so that C<tied> hashes can be given
+real scalars as keys rather than plain strings (nontied hashes still
+can only use strings as keys). New extensions must use the new hash
+access functions and macros if they wish to use C<SV*> keys. These
+additions also make it feasible to manipulate C<HE*>s (hash entries),
+which can be more efficient. See L<perlguts> for details.
+
+=back
+
+=head1 Documentation Changes
+
+Many of the base and library pods were updated. These
+new pods are included in section 1:
+
+=over 4
+
+=item L<perldelta>
+
+This document.
+
+=item L<perlfaq>
+
+Frequently asked questions.
+
+=item L<perllocale>
+
+Locale support (internationalization and localization).
+
+=item L<perltoot>
+
+Tutorial on Perl OO programming.
+
+=item L<perlapio>
+
+Perl internal IO abstraction interface.
+
+=item L<perlmodlib>
+
+Perl module library and recommended practice for module creation.
+Extracted from L<perlmod> (which is much smaller as a result).
+
+=item L<perldebug>
+
+Although not new, this has been massively updated.
+
+=item L<perlsec>
+
+Although not new, this has been massively updated.
+
+=back
+
+=head1 New Diagnostics
+
+Several new conditions will trigger warnings that were
+silent before. Some only affect certain platforms.
+The following new warnings and errors outline these.
+These messages are classified as follows (listed in
+increasing order of desperation):
+
+ (W) A warning (optional).
+ (D) A deprecation (optional).
+ (S) A severe warning (mandatory).
+ (F) A fatal error (trappable).
+ (P) An internal error you should never see (trappable).
+ (X) A very fatal error (nontrappable).
+ (A) An alien error message (not generated by Perl).
+
+=over 4
+
+=item "my" variable %s masks earlier declaration in same scope
+
+(W) A lexical variable has been redeclared in the same scope, effectively
+eliminating all access to the previous instance. This is almost always
+a typographical error. Note that the earlier variable will still exist
+until the end of the scope or until all closure referents to it are
+destroyed.
+
+=item %s argument is not a HASH element or slice
+
+(F) The argument to delete() must be either a hash element, such as
+
+ $foo{$bar}
+ $ref->[12]->{"susie"}
+
+or a hash slice, such as
+
+ @foo{$bar, $baz, $xyzzy}
+ @{$ref->[12]}{"susie", "queue"}
+
+=item Allocation too large: %lx
+
+(X) You can't allocate more than 64K on an MS-DOS machine.
+
+=item Allocation too large
+
+(F) You can't allocate more than 2^31+"small amount" bytes.
+
+=item Applying %s to %s will act on scalar(%s)
+
+(W) The pattern match (//), substitution (s///), and transliteration (tr///)
+operators work on scalar values. If you apply one of them to an array
+or a hash, it will convert the array or hash to a scalar value (the
+length of an array or the population info of a hash) and then work on
+that scalar value. This is probably not what you meant to do. See
+L<perlfunc/grep> and L<perlfunc/map> for alternatives.
+
+=item Attempt to free nonexistent shared string
+
+(P) Perl maintains a reference counted internal table of strings to
+optimize the storage and access of hash keys and other strings. This
+indicates someone tried to decrement the reference count of a string
+that can no longer be found in the table.
+
+=item Attempt to use reference as lvalue in substr
+
+(W) You supplied a reference as the first argument to substr() used
+as an lvalue, which is pretty strange. Perhaps you forgot to
+dereference it first. See L<perlfunc/substr>.
+
+=item Bareword "%s" refers to nonexistent package
+
+(W) You used a qualified bareword of the form C<Foo::>, but
+the compiler saw no other uses of that namespace before that point.
+Perhaps you need to predeclare a package?
+
+=item Can't redefine active sort subroutine %s
+
+(F) Perl optimizes the internal handling of sort subroutines and keeps
+pointers into them. You tried to redefine one such sort subroutine when it
+was currently active, which is not allowed. If you really want to do
+this, you should write C<sort { &func } @x> instead of C<sort func @x>.
+
+=item Can't use bareword ("%s") as %s ref while "strict refs" in use
+
+(F) Only hard references are allowed by "strict refs". Symbolic references
+are disallowed. See L<perlref>.
+
+=item Cannot resolve method `%s' overloading `%s' in package `%s'
+
+(P) Internal error trying to resolve overloading specified by a method
+name (as opposed to a subroutine reference).
+
+=item Constant subroutine %s redefined
+
+(S) You redefined a subroutine which had previously been eligible for
+inlining. See L<perlsub/"Constant Functions"> for commentary and
+workarounds.
+
+=item Constant subroutine %s undefined
+
+(S) You undefined a subroutine which had previously been eligible for
+inlining. See L<perlsub/"Constant Functions"> for commentary and
+workarounds.
+
+=item Copy method did not return a reference
+
+(F) The method which overloads "=" is buggy. See L<overload/Copy Constructor>.
+
+=item Died
+
+(F) You passed die() an empty string (the equivalent of C<die "">) or
+you called it with no args and both C<$@> and C<$_> were empty.
+
+=item Exiting pseudo-block via %s
+
+(W) You are exiting a rather special block construct (like a sort block or
+subroutine) by unconventional means, such as a goto, or a loop control
+statement. See L<perlfunc/sort>.
+
+=item Identifier too long
+
+(F) Perl limits identifiers (names for variables, functions, etc.) to
+252 characters for simple names, somewhat more for compound names (like
+C<$A::B>). You've exceeded Perl's limits. Future versions of Perl are
+likely to eliminate these arbitrary limitations.
+
+=item Illegal character %s (carriage return)
+
+(F) A carriage return character was found in the input. This is an
+error, and not a warning, because carriage return characters can break
+multi-line strings, including here documents (e.g., C<print <<EOF;>).
+
+=item Illegal switch in PERL5OPT: %s
+
+(X) The PERL5OPT environment variable may only be used to set the
+following switches: B<-[DIMUdmw]>.
+
+=item Integer overflow in hex number
+
+(S) The literal hex number you have specified is too big for your
+architecture. On a 32-bit architecture the largest hex literal is
+0xFFFFFFFF.
+
+=item Integer overflow in octal number
+
+(S) The literal octal number you have specified is too big for your
+architecture. On a 32-bit architecture the largest octal literal is
+037777777777.
+
+=item internal error: glob failed
+
+(P) Something went wrong with the external program(s) used for C<glob>
+and C<< <*.c> >>. This may mean that your csh (C shell) is
+broken. If so, you should change all of the csh-related variables in
+config.sh: If you have tcsh, make the variables refer to it as if it
+were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all
+empty (except that C<d_csh> should be C<'undef'>) so that Perl will
+think csh is missing. In either case, after editing config.sh, run
+C<./Configure -S> and rebuild Perl.
+
+=item Invalid conversion in %s: "%s"
+
+(W) Perl does not understand the given format conversion.
+See L<perlfunc/sprintf>.
+
+=item Invalid type in pack: '%s'
+
+(F) The given character is not a valid pack type. See L<perlfunc/pack>.
+
+=item Invalid type in unpack: '%s'
+
+(F) The given character is not a valid unpack type. See L<perlfunc/unpack>.
+
+=item Name "%s::%s" used only once: possible typo
+
+(W) Typographical errors often show up as unique variable names.
+If you had a good reason for having a unique name, then just mention
+it again somehow to suppress the message (the C<use vars> pragma is
+provided for just this purpose).
+
+=item Null picture in formline
+
+(F) The first argument to formline must be a valid format picture
+specification. It was found to be empty, which probably means you
+supplied it an uninitialized value. See L<perlform>.
+
+=item Offset outside string
+
+(F) You tried to do a read/write/send/recv operation with an offset
+pointing outside the buffer. This is difficult to imagine.
+The sole exception to this is that C<sysread()>ing past the buffer
+will extend the buffer and zero pad the new area.
+
+=item Out of memory!
+
+(X|F) The malloc() function returned 0, indicating there was insufficient
+remaining memory (or virtual memory) to satisfy the request.
+
+The request was judged to be small, so the possibility to trap it
+depends on the way Perl was compiled. By default it is not trappable.
+However, if compiled for this, Perl may use the contents of C<$^M> as
+an emergency pool after die()ing with this message. In this case the
+error is trappable I<once>.
+
+=item Out of memory during request for %s
+
+(F) The malloc() function returned 0, indicating there was insufficient
+remaining memory (or virtual memory) to satisfy the request. However,
+the request was judged large enough (compile-time default is 64K), so
+a possibility to shut down by trapping this error is granted.
+
+=item panic: frexp
+
+(P) The library function frexp() failed, making printf("%f") impossible.
+
+=item Possible attempt to put comments in qw() list
+
+(W) qw() lists contain items separated by whitespace; as with literal
+strings, comment characters are not ignored, but are instead treated
+as literal data. (You may have used different delimiters than the
+parentheses shown here; braces are also frequently used.)
+
+You probably wrote something like this:
+
+ @list = qw(
+ a # a comment
+ b # another comment
+ );
+
+when you should have written this:
+
+ @list = qw(
+ a
+ b
+ );
+
+If you really want comments, build your list the
+old-fashioned way, with quotes and commas:
+
+ @list = (
+ 'a', # a comment
+ 'b', # another comment
+ );
+
+=item Possible attempt to separate words with commas
+
+(W) qw() lists contain items separated by whitespace; therefore commas
+aren't needed to separate the items. (You may have used different
+delimiters than the parentheses shown here; braces are also frequently
+used.)
+
+You probably wrote something like this:
+
+ qw! a, b, c !;
+
+which puts literal commas into some of the list items. Write it without
+commas if you don't want them to appear in your data:
+
+ qw! a b c !;
+
+=item Scalar value @%s{%s} better written as $%s{%s}
+
+(W) You've used a hash slice (indicated by @) to select a single element of
+a hash. Generally it's better to ask for a scalar value (indicated by $).
+The difference is that C<$foo{&bar}> always behaves like a scalar, both when
+assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves
+like a list when you assign to it, and provides a list context to its
+subscript, which can do weird things if you're expecting only one subscript.
+
+=item Stub found while resolving method `%s' overloading `%s' in %s
+
+(P) Overloading resolution over @ISA tree may be broken by importing stubs.
+Stubs should never be implicitly created, but explicit calls to C<can>
+may break this.
+
+=item Too late for "B<-T>" option
+
+(X) The #! line (or local equivalent) in a Perl script contains the
+B<-T> option, but Perl was not invoked with B<-T> in its argument
+list. This is an error because, by the time Perl discovers a B<-T> in
+a script, it's too late to properly taint everything from the
+environment. So Perl gives up.
+
+=item untie attempted while %d inner references still exist
+
+(W) A copy of the object returned from C<tie> (or C<tied>) was still
+valid when C<untie> was called.
+
+=item Unrecognized character %s
+
+(F) The Perl parser has no idea what to do with the specified character
+in your Perl script (or eval). Perhaps you tried to run a compressed
+script, a binary program, or a directory as a Perl program.
+
+=item Unsupported function fork
+
+(F) Your version of executable does not support forking.
+
+Note that under some systems, like OS/2, there may be different flavors of
+Perl executables, some of which may support fork, some not. Try changing
+the name you call Perl by to C<perl_>, C<perl__>, and so on.
+
+=item Use of "$$<digit>" to mean "${$}<digit>" is deprecated
+
+(D) Perl versions before 5.004 misinterpreted any type marker followed
+by "$" and a digit. For example, "$$0" was incorrectly taken to mean
+"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
+
+However, the developers of Perl 5.004 could not fix this bug completely,
+because at least two widely-used modules depend on the old meaning of
+"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
+old (broken) way inside strings; but it generates this message as a
+warning. And in Perl 5.005, this special treatment will cease.
+
+=item Value of %s can be "0"; test with defined()
+
+(W) In a conditional expression, you used <HANDLE>, <*> (glob), C<each()>,
+or C<readdir()> as a boolean value. Each of these constructs can return a
+value of "0"; that would make the conditional expression false, which is
+probably not what you intended. When using these constructs in conditional
+expressions, test their values with the C<defined> operator.
+
+=item Variable "%s" may be unavailable
+
+(W) An inner (nested) I<anonymous> subroutine is inside a I<named>
+subroutine, and outside that is another subroutine; and the anonymous
+(innermost) subroutine is referencing a lexical variable defined in
+the outermost subroutine. For example:
+
+ sub outermost { my $a; sub middle { sub { $a } } }
+
+If the anonymous subroutine is called or referenced (directly or
+indirectly) from the outermost subroutine, it will share the variable
+as you would expect. But if the anonymous subroutine is called or
+referenced when the outermost subroutine is not active, it will see
+the value of the shared variable as it was before and during the
+*first* call to the outermost subroutine, which is probably not what
+you want.
+
+In these circumstances, it is usually best to make the middle
+subroutine anonymous, using the C<sub {}> syntax. Perl has specific
+support for shared variables in nested anonymous subroutines; a named
+subroutine in between interferes with this feature.
+
+=item Variable "%s" will not stay shared
+
+(W) An inner (nested) I<named> subroutine is referencing a lexical
+variable defined in an outer subroutine.
+
+When the inner subroutine is called, it will probably see the value of
+the outer subroutine's variable as it was before and during the
+*first* call to the outer subroutine; in this case, after the first
+call to the outer subroutine is complete, the inner and outer
+subroutines will no longer share a common value for the variable. In
+other words, the variable will no longer be shared.
+
+Furthermore, if the outer subroutine is anonymous and references a
+lexical variable outside itself, then the outer and inner subroutines
+will I<never> share the given variable.
+
+This problem can usually be solved by making the inner subroutine
+anonymous, using the C<sub {}> syntax. When inner anonymous subs that
+reference variables in outer subroutines are called or referenced,
+they are automatically rebound to the current values of such
+variables.
+
+=item Warning: something's wrong
+
+(W) You passed warn() an empty string (the equivalent of C<warn "">) or
+you called it with no args and C<$_> was empty.
+
+=item Ill-formed logical name |%s| in prime_env_iter
+
+(W) A warning peculiar to VMS. A logical name was encountered when preparing
+to iterate over %ENV which violates the syntactic rules governing logical
+names. Since it cannot be translated normally, it is skipped, and will not
+appear in %ENV. This may be a benign occurrence, as some software packages
+might directly modify logical name tables and introduce nonstandard names,
+or it may indicate that a logical name table has been corrupted.
+
+=item Got an error from DosAllocMem
+
+(P) An error peculiar to OS/2. Most probably you're using an obsolete
+version of Perl, and this should not happen anyway.
+
+=item Malformed PERLLIB_PREFIX
+
+(F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
+
+ prefix1;prefix2
+
+or
+
+ prefix1 prefix2
+
+with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix
+of a builtin library search path, prefix2 is substituted. The error
+may appear if components are not found, or are too long. See
+"PERLLIB_PREFIX" in F<README.os2>.
+
+=item PERL_SH_DIR too long
+
+(F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
+C<sh>-shell in. See "PERL_SH_DIR" in F<README.os2>.
+
+=item Process terminated by SIG%s
+
+(W) This is a standard message issued by OS/2 applications, while *nix
+applications die in silence. It is considered a feature of the OS/2
+port. One can easily disable this by appropriate sighandlers, see
+L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
+in F<README.os2>.
+
+=back
+
+=head1 BUGS
+
+If you find what you think is a bug, you might check the headers of
+recently posted articles in the comp.lang.perl.misc newsgroup.
+There may also be information at http://www.perl.com/perl/ , the Perl
+Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Make sure you trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl. This file has been
+significantly updated for 5.004, so even veteran users should
+look through it.
+
+The F<README> file for general stuff.
+
+The F<Copying> file for copyright information.
+
+=head1 HISTORY
+
+Constructed by Tom Christiansen, grabbing material with permission
+from innumerable contributors, with kibitzing by more than a few Perl
+porters.
+
+Last update: Wed May 14 11:14:09 EDT 1997
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5005delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5005delta.pod
new file mode 100644
index 00000000000..cabdf9eb7cb
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5005delta.pod
@@ -0,0 +1,993 @@
+=head1 NAME
+
+perl5005delta - what's new for perl5.005
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.004 release and this one.
+
+=head1 About the new versioning system
+
+Perl is now developed on two tracks: a maintenance track that makes
+small, safe updates to released production versions with emphasis on
+compatibility; and a development track that pursues more aggressive
+evolution. Maintenance releases (which should be considered production
+quality) have subversion numbers that run from C<1> to C<49>, and
+development releases (which should be considered "alpha" quality) run
+from C<50> to C<99>.
+
+Perl 5.005 is the combined product of the new dual-track development
+scheme.
+
+=head1 Incompatible Changes
+
+=head2 WARNING: This version is not binary compatible with Perl 5.004.
+
+Starting with Perl 5.004_50 there were many deep and far-reaching changes
+to the language internals. If you have dynamically loaded extensions
+that you built under perl 5.003 or 5.004, you can continue to use them
+with 5.004, but you will need to rebuild and reinstall those extensions
+to use them 5.005. See F<INSTALL> for detailed instructions on how to
+upgrade.
+
+=head2 Default installation structure has changed
+
+The new Configure defaults are designed to allow a smooth upgrade from
+5.004 to 5.005, but you should read F<INSTALL> for a detailed
+discussion of the changes in order to adapt them to your system.
+
+=head2 Perl Source Compatibility
+
+When none of the experimental features are enabled, there should be
+very few user-visible Perl source compatibility issues.
+
+If threads are enabled, then some caveats apply. C<@_> and C<$_> become
+lexical variables. The effect of this should be largely transparent to
+the user, but there are some boundary conditions under which user will
+need to be aware of the issues. For example, C<local(@_)> results in
+a "Can't localize lexical variable @_ ..." message. This may be enabled
+in a future version.
+
+Some new keywords have been introduced. These are generally expected to
+have very little impact on compatibility. See L<New C<INIT> keyword>,
+L<New C<lock> keyword>, and L<New C<qrE<sol>E<sol>> operator>.
+
+Certain barewords are now reserved. Use of these will provoke a warning
+if you have asked for them with the C<-w> switch.
+See L<C<our> is now a reserved word>.
+
+=head2 C Source Compatibility
+
+There have been a large number of changes in the internals to support
+the new features in this release.
+
+=over 4
+
+=item *
+
+Core sources now require ANSI C compiler
+
+An ANSI C compiler is now B<required> to build perl. See F<INSTALL>.
+
+=item *
+
+All Perl global variables must now be referenced with an explicit prefix
+
+All Perl global variables that are visible for use by extensions now
+have a C<PL_> prefix. New extensions should C<not> refer to perl globals
+by their unqualified names. To preserve sanity, we provide limited
+backward compatibility for globals that are being widely used like
+C<sv_undef> and C<na> (which should now be written as C<PL_sv_undef>,
+C<PL_na> etc.)
+
+If you find that your XS extension does not compile anymore because a
+perl global is not visible, try adding a C<PL_> prefix to the global
+and rebuild.
+
+It is strongly recommended that all functions in the Perl API that don't
+begin with C<perl> be referenced with a C<Perl_> prefix. The bare function
+names without the C<Perl_> prefix are supported with macros, but this
+support may cease in a future release.
+
+See L<perlapi>.
+
+=item *
+
+Enabling threads has source compatibility issues
+
+Perl built with threading enabled requires extensions to use the new
+C<dTHR> macro to initialize the handle to access per-thread data.
+If you see a compiler error that talks about the variable C<thr> not
+being declared (when building a module that has XS code), you need
+to add C<dTHR;> at the beginning of the block that elicited the error.
+
+The API function C<perl_get_sv("@",GV_ADD)> should be used instead of
+directly accessing perl globals as C<GvSV(errgv)>. The API call is
+backward compatible with existing perls and provides source compatibility
+with threading is enabled.
+
+See L<"C Source Compatibility"> for more information.
+
+=back
+
+=head2 Binary Compatibility
+
+This version is NOT binary compatible with older versions. All extensions
+will need to be recompiled. Further binaries built with threads enabled
+are incompatible with binaries built without. This should largely be
+transparent to the user, as all binary incompatible configurations have
+their own unique architecture name, and extension binaries get installed at
+unique locations. This allows coexistence of several configurations in
+the same directory hierarchy. See F<INSTALL>.
+
+=head2 Security fixes may affect compatibility
+
+A few taint leaks and taint omissions have been corrected. This may lead
+to "failure" of scripts that used to work with older versions. Compiling
+with -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes
+to the tainting behavior. But note that the resulting perl will have
+known insecurities.
+
+Oneliners with the C<-e> switch do not create temporary files anymore.
+
+=head2 Relaxed new mandatory warnings introduced in 5.004
+
+Many new warnings that were introduced in 5.004 have been made
+optional. Some of these warnings are still present, but perl's new
+features make them less often a problem. See L<New Diagnostics>.
+
+=head2 Licensing
+
+Perl has a new Social Contract for contributors. See F<Porting/Contract>.
+
+The license included in much of the Perl documentation has changed.
+Most of the Perl documentation was previously under the implicit GNU
+General Public License or the Artistic License (at the user's choice).
+Now much of the documentation unambiguously states the terms under which
+it may be distributed. Those terms are in general much less restrictive
+than the GNU GPL. See L<perl> and the individual perl manpages listed
+therein.
+
+=head1 Core Changes
+
+
+=head2 Threads
+
+WARNING: Threading is considered an B<experimental> feature. Details of the
+implementation may change without notice. There are known limitations
+and some bugs. These are expected to be fixed in future versions.
+
+See F<README.threads>.
+
+=head2 Compiler
+
+WARNING: The Compiler and related tools are considered B<experimental>.
+Features may change without notice, and there are known limitations
+and bugs. Since the compiler is fully external to perl, the default
+configuration will build and install it.
+
+The Compiler produces three different types of transformations of a
+perl program. The C backend generates C code that captures perl's state
+just before execution begins. It eliminates the compile-time overheads
+of the regular perl interpreter, but the run-time performance remains
+comparatively the same. The CC backend generates optimized C code
+equivalent to the code path at run-time. The CC backend has greater
+potential for big optimizations, but only a few optimizations are
+implemented currently. The Bytecode backend generates a platform
+independent bytecode representation of the interpreter's state
+just before execution. Thus, the Bytecode back end also eliminates
+much of the compilation overhead of the interpreter.
+
+The compiler comes with several valuable utilities.
+
+C<B::Lint> is an experimental module to detect and warn about suspicious
+code, especially the cases that the C<-w> switch does not detect.
+
+C<B::Deparse> can be used to demystify perl code, and understand
+how perl optimizes certain constructs.
+
+C<B::Xref> generates cross reference reports of all definition and use
+of variables, subroutines and formats in a program.
+
+C<B::Showlex> show the lexical variables used by a subroutine or file
+at a glance.
+
+C<perlcc> is a simple frontend for compiling perl.
+
+See C<ext/B/README>, L<B>, and the respective compiler modules.
+
+=head2 Regular Expressions
+
+Perl's regular expression engine has been seriously overhauled, and
+many new constructs are supported. Several bugs have been fixed.
+
+Here is an itemized summary:
+
+=over 4
+
+=item Many new and improved optimizations
+
+Changes in the RE engine:
+
+ Unneeded nodes removed;
+ Substrings merged together;
+ New types of nodes to process (SUBEXPR)* and similar expressions
+ quickly, used if the SUBEXPR has no side effects and matches
+ strings of the same length;
+ Better optimizations by lookup for constant substrings;
+ Better search for constants substrings anchored by $ ;
+
+Changes in Perl code using RE engine:
+
+ More optimizations to s/longer/short/;
+ study() was not working;
+ /blah/ may be optimized to an analogue of index() if $& $` $' not seen;
+ Unneeded copying of matched-against string removed;
+ Only matched part of the string is copying if $` $' were not seen;
+
+=item Many bug fixes
+
+Note that only the major bug fixes are listed here. See F<Changes> for others.
+
+ Backtracking might not restore start of $3.
+ No feedback if max count for * or + on "complex" subexpression
+ was reached, similarly (but at compile time) for {3,34567}
+ Primitive restrictions on max count introduced to decrease a
+ possibility of a segfault;
+ (ZERO-LENGTH)* could segfault;
+ (ZERO-LENGTH)* was prohibited;
+ Long REs were not allowed;
+ /RE/g could skip matches at the same position after a
+ zero-length match;
+
+=item New regular expression constructs
+
+The following new syntax elements are supported:
+
+ (?<=RE)
+ (?<!RE)
+ (?{ CODE })
+ (?i-x)
+ (?i:RE)
+ (?(COND)YES_RE|NO_RE)
+ (?>RE)
+ \z
+
+=item New operator for precompiled regular expressions
+
+See L<New C<qrE<sol>E<sol>> operator>.
+
+=item Other improvements
+
+ Better debugging output (possibly with colors),
+ even from non-debugging Perl;
+ RE engine code now looks like C, not like assembler;
+ Behaviour of RE modifiable by `use re' directive;
+ Improved documentation;
+ Test suite significantly extended;
+ Syntax [:^upper:] etc., reserved inside character classes;
+
+=item Incompatible changes
+
+ (?i) localized inside enclosing group;
+ $( is not interpolated into RE any more;
+ /RE/g may match at the same position (with non-zero length)
+ after a zero-length match (bug fix).
+
+=back
+
+See L<perlre> and L<perlop>.
+
+=head2 Improved malloc()
+
+See banner at the beginning of C<malloc.c> for details.
+
+=head2 Quicksort is internally implemented
+
+Perl now contains its own highly optimized qsort() routine. The new qsort()
+is resistant to inconsistent comparison functions, so Perl's C<sort()> will
+not provoke coredumps any more when given poorly written sort subroutines.
+(Some C library C<qsort()>s that were being used before used to have this
+problem.) In our testing, the new C<qsort()> required the minimal number
+of pair-wise compares on average, among all known C<qsort()> implementations.
+
+See C<perlfunc/sort>.
+
+=head2 Reliable signals
+
+Perl's signal handling is susceptible to random crashes, because signals
+arrive asynchronously, and the Perl runtime is not reentrant at arbitrary
+times.
+
+However, one experimental implementation of reliable signals is available
+when threads are enabled. See C<Thread::Signal>. Also see F<INSTALL> for
+how to build a Perl capable of threads.
+
+=head2 Reliable stack pointers
+
+The internals now reallocate the perl stack only at predictable times.
+In particular, magic calls never trigger reallocations of the stack,
+because all reentrancy of the runtime is handled using a "stack of stacks".
+This should improve reliability of cached stack pointers in the internals
+and in XSUBs.
+
+=head2 More generous treatment of carriage returns
+
+Perl used to complain if it encountered literal carriage returns in
+scripts. Now they are mostly treated like whitespace within program text.
+Inside string literals and here documents, literal carriage returns are
+ignored if they occur paired with linefeeds, or get interpreted as whitespace
+if they stand alone. This behavior means that literal carriage returns
+in files should be avoided. You can get the older, more compatible (but
+less generous) behavior by defining the preprocessor symbol
+C<PERL_STRICT_CR> when building perl. Of course, all this has nothing
+whatever to do with how escapes like C<\r> are handled within strings.
+
+Note that this doesn't somehow magically allow you to keep all text files
+in DOS format. The generous treatment only applies to files that perl
+itself parses. If your C compiler doesn't allow carriage returns in
+files, you may still be unable to build modules that need a C compiler.
+
+=head2 Memory leaks
+
+C<substr>, C<pos> and C<vec> don't leak memory anymore when used in lvalue
+context. Many small leaks that impacted applications that embed multiple
+interpreters have been fixed.
+
+=head2 Better support for multiple interpreters
+
+The build-time option C<-DMULTIPLICITY> has had many of the details
+reworked. Some previously global variables that should have been
+per-interpreter now are. With care, this allows interpreters to call
+each other. See the C<PerlInterp> extension on CPAN.
+
+=head2 Behavior of local() on array and hash elements is now well-defined
+
+See L<perlsub/"Temporary Values via local()">.
+
+=head2 C<%!> is transparently tied to the L<Errno> module
+
+See L<perlvar>, and L<Errno>.
+
+=head2 Pseudo-hashes are supported
+
+See L<perlref>.
+
+=head2 C<EXPR foreach EXPR> is supported
+
+See L<perlsyn>.
+
+=head2 Keywords can be globally overridden
+
+See L<perlsub>.
+
+=head2 C<$^E> is meaningful on Win32
+
+See L<perlvar>.
+
+=head2 C<foreach (1..1000000)> optimized
+
+C<foreach (1..1000000)> is now optimized into a counting loop. It does
+not try to allocate a 1000000-size list anymore.
+
+=head2 C<Foo::> can be used as implicitly quoted package name
+
+Barewords caused unintuitive behavior when a subroutine with the same
+name as a package happened to be defined. Thus, C<new Foo @args>,
+use the result of the call to C<Foo()> instead of C<Foo> being treated
+as a literal. The recommended way to write barewords in the indirect
+object slot is C<new Foo:: @args>. Note that the method C<new()> is
+called with a first argument of C<Foo>, not C<Foo::> when you do that.
+
+=head2 C<exists $Foo::{Bar::}> tests existence of a package
+
+It was impossible to test for the existence of a package without
+actually creating it before. Now C<exists $Foo::{Bar::}> can be
+used to test if the C<Foo::Bar> namespace has been created.
+
+=head2 Better locale support
+
+See L<perllocale>.
+
+=head2 Experimental support for 64-bit platforms
+
+Perl5 has always had 64-bit support on systems with 64-bit longs.
+Starting with 5.005, the beginnings of experimental support for systems
+with 32-bit long and 64-bit 'long long' integers has been added.
+If you add -DUSE_LONG_LONG to your ccflags in config.sh (or manually
+define it in perl.h) then perl will be built with 'long long' support.
+There will be many compiler warnings, and the resultant perl may not
+work on all systems. There are many other issues related to
+third-party extensions and libraries. This option exists to allow
+people to work on those issues.
+
+=head2 prototype() returns useful results on builtins
+
+See L<perlfunc/prototype>.
+
+=head2 Extended support for exception handling
+
+C<die()> now accepts a reference value, and C<$@> gets set to that
+value in exception traps. This makes it possible to propagate
+exception objects. This is an undocumented B<experimental> feature.
+
+=head2 Re-blessing in DESTROY() supported for chaining DESTROY() methods
+
+See L<perlobj/Destructors>.
+
+=head2 All C<printf> format conversions are handled internally
+
+See L<perlfunc/printf>.
+
+=head2 New C<INIT> keyword
+
+C<INIT> subs are like C<BEGIN> and C<END>, but they get run just before
+the perl runtime begins execution. e.g., the Perl Compiler makes use of
+C<INIT> blocks to initialize and resolve pointers to XSUBs.
+
+=head2 New C<lock> keyword
+
+The C<lock> keyword is the fundamental synchronization primitive
+in threaded perl. When threads are not enabled, it is currently a noop.
+
+To minimize impact on source compatibility this keyword is "weak", i.e., any
+user-defined subroutine of the same name overrides it, unless a C<use Thread>
+has been seen.
+
+=head2 New C<qr//> operator
+
+The C<qr//> operator, which is syntactically similar to the other quote-like
+operators, is used to create precompiled regular expressions. This compiled
+form can now be explicitly passed around in variables, and interpolated in
+other regular expressions. See L<perlop>.
+
+=head2 C<our> is now a reserved word
+
+Calling a subroutine with the name C<our> will now provoke a warning when
+using the C<-w> switch.
+
+=head2 Tied arrays are now fully supported
+
+See L<Tie::Array>.
+
+=head2 Tied handles support is better
+
+Several missing hooks have been added. There is also a new base class for
+TIEARRAY implementations. See L<Tie::Array>.
+
+=head2 4th argument to substr
+
+substr() can now both return and replace in one operation. The optional
+4th argument is the replacement string. See L<perlfunc/substr>.
+
+=head2 Negative LENGTH argument to splice
+
+splice() with a negative LENGTH argument now work similar to what the
+LENGTH did for substr(). Previously a negative LENGTH was treated as
+0. See L<perlfunc/splice>.
+
+=head2 Magic lvalues are now more magical
+
+When you say something like C<substr($x, 5) = "hi">, the scalar returned
+by substr() is special, in that any modifications to it affect $x.
+(This is called a 'magic lvalue' because an 'lvalue' is something on
+the left side of an assignment.) Normally, this is exactly what you
+would expect to happen, but Perl uses the same magic if you use substr(),
+pos(), or vec() in a context where they might be modified, like taking
+a reference with C<\> or as an argument to a sub that modifies C<@_>.
+In previous versions, this 'magic' only went one way, but now changes
+to the scalar the magic refers to ($x in the above example) affect the
+magic lvalue too. For instance, this code now acts differently:
+
+ $x = "hello";
+ sub printit {
+ $x = "g'bye";
+ print $_[0], "\n";
+ }
+ printit(substr($x, 0, 5));
+
+In previous versions, this would print "hello", but it now prints "g'bye".
+
+=head2 <> now reads in records
+
+If C<$/> is a reference to an integer, or a scalar that holds an integer,
+<> will read in records instead of lines. For more info, see
+L<perlvar/$E<sol>>.
+
+=head1 Supported Platforms
+
+Configure has many incremental improvements. Site-wide policy for building
+perl can now be made persistent, via Policy.sh. Configure also records
+the command-line arguments used in F<config.sh>.
+
+=head2 New Platforms
+
+BeOS is now supported. See F<README.beos>.
+
+DOS is now supported under the DJGPP tools. See F<README.dos> (installed
+as L<perldos> on some systems).
+
+MiNT is now supported. See F<README.mint>.
+
+MPE/iX is now supported. See F<README.mpeix>.
+
+MVS (aka OS390, aka Open Edition) is now supported. See F<README.os390>
+(installed as L<perlos390> on some systems).
+
+Stratus VOS is now supported. See F<README.vos>.
+
+=head2 Changes in existing support
+
+Win32 support has been vastly enhanced. Support for Perl Object, a C++
+encapsulation of Perl. GCC and EGCS are now supported on Win32.
+See F<README.win32>, aka L<perlwin32>.
+
+VMS configuration system has been rewritten. See F<README.vms> (installed
+as L<README_vms> on some systems).
+
+The hints files for most Unix platforms have seen incremental improvements.
+
+=head1 Modules and Pragmata
+
+=head2 New Modules
+
+=over 4
+
+=item B
+
+Perl compiler and tools. See L<B>.
+
+=item Data::Dumper
+
+A module to pretty print Perl data. See L<Data::Dumper>.
+
+=item Dumpvalue
+
+A module to dump perl values to the screen. See L<Dumpvalue>.
+
+=item Errno
+
+A module to look up errors more conveniently. See L<Errno>.
+
+=item File::Spec
+
+A portable API for file operations.
+
+=item ExtUtils::Installed
+
+Query and manage installed modules.
+
+=item ExtUtils::Packlist
+
+Manipulate .packlist files.
+
+=item Fatal
+
+Make functions/builtins succeed or die.
+
+=item IPC::SysV
+
+Constants and other support infrastructure for System V IPC operations
+in perl.
+
+=item Test
+
+A framework for writing test suites.
+
+=item Tie::Array
+
+Base class for tied arrays.
+
+=item Tie::Handle
+
+Base class for tied handles.
+
+=item Thread
+
+Perl thread creation, manipulation, and support.
+
+=item attrs
+
+Set subroutine attributes.
+
+=item fields
+
+Compile-time class fields.
+
+=item re
+
+Various pragmata to control behavior of regular expressions.
+
+=back
+
+=head2 Changes in existing modules
+
+=over 4
+
+=item Benchmark
+
+You can now run tests for I<x> seconds instead of guessing the right
+number of tests to run.
+
+Keeps better time.
+
+=item Carp
+
+Carp has a new function cluck(). cluck() warns, like carp(), but also adds
+a stack backtrace to the error message, like confess().
+
+=item CGI
+
+CGI has been updated to version 2.42.
+
+=item Fcntl
+
+More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
+large (more than 4G) file access (the 64-bit support is not yet
+working, though, so no need to get overly excited), Free/Net/OpenBSD
+locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and
+O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR.
+
+=item Math::Complex
+
+The accessors methods Re, Im, arg, abs, rho, theta, methods can
+($z->Re()) now also act as mutators ($z->Re(3)).
+
+=item Math::Trig
+
+A little bit of radial trigonometry (cylindrical and spherical) added,
+for example the great circle distance.
+
+=item POSIX
+
+POSIX now has its own platform-specific hints files.
+
+=item DB_File
+
+DB_File supports version 2.x of Berkeley DB. See C<ext/DB_File/Changes>.
+
+=item MakeMaker
+
+MakeMaker now supports writing empty makefiles, provides a way to
+specify that site umask() policy should be honored. There is also
+better support for manipulation of .packlist files, and getting
+information about installed modules.
+
+Extensions that have both architecture-dependent and
+architecture-independent files are now always installed completely in
+the architecture-dependent locations. Previously, the shareable parts
+were shared both across architectures and across perl versions and were
+therefore liable to be overwritten with newer versions that might have
+subtle incompatibilities.
+
+=item CPAN
+
+See L<perlmodinstall> and L<CPAN>.
+
+=item Cwd
+
+Cwd::cwd is faster on most platforms.
+
+=back
+
+=head1 Utility Changes
+
+C<h2ph> and related utilities have been vastly overhauled.
+
+C<perlcc>, a new experimental front end for the compiler is available.
+
+The crude GNU C<configure> emulator is now called C<configure.gnu> to
+avoid trampling on C<Configure> under case-insensitive filesystems.
+
+C<perldoc> used to be rather slow. The slower features are now optional.
+In particular, case-insensitive searches need the C<-i> switch, and
+recursive searches need C<-r>. You can set these switches in the
+C<PERLDOC> environment variable to get the old behavior.
+
+=head1 Documentation Changes
+
+Config.pm now has a glossary of variables.
+
+F<Porting/patching.pod> has detailed instructions on how to create and
+submit patches for perl.
+
+L<perlport> specifies guidelines on how to write portably.
+
+L<perlmodinstall> describes how to fetch and install modules from C<CPAN>
+sites.
+
+Some more Perl traps are documented now. See L<perltrap>.
+
+L<perlopentut> gives a tutorial on using open().
+
+L<perlreftut> gives a tutorial on references.
+
+L<perlthrtut> gives a tutorial on threads.
+
+=head1 New Diagnostics
+
+=over 4
+
+=item Ambiguous call resolved as CORE::%s(), qualify as such or use &
+
+(W) A subroutine you have declared has the same name as a Perl keyword,
+and you have used the name without qualification for calling one or the
+other. Perl decided to call the builtin because the subroutine is
+not imported.
+
+To force interpretation as a subroutine call, either put an ampersand
+before the subroutine name, or qualify the name with its package.
+Alternatively, you can import the subroutine (or pretend that it's
+imported with the C<use subs> pragma).
+
+To silently interpret it as the Perl operator, use the C<CORE::> prefix
+on the operator (e.g. C<CORE::log($x)>) or by declaring the subroutine
+to be an object method (see L<attrs>).
+
+=item Bad index while coercing array into hash
+
+(F) The index looked up in the hash found as the 0'th element of a
+pseudo-hash is not legal. Index values must be at 1 or greater.
+See L<perlref>.
+
+=item Bareword "%s" refers to nonexistent package
+
+(W) You used a qualified bareword of the form C<Foo::>, but
+the compiler saw no other uses of that namespace before that point.
+Perhaps you need to predeclare a package?
+
+=item Can't call method "%s" on an undefined value
+
+(F) You used the syntax of a method call, but the slot filled by the
+object reference or package name contains an undefined value.
+Something like this will reproduce the error:
+
+ $BADREF = 42;
+ process $BADREF 1,2,3;
+ $BADREF->process(1,2,3);
+
+=item Can't check filesystem of script "%s" for nosuid
+
+(P) For some reason you can't check the filesystem of the script for nosuid.
+
+=item Can't coerce array into hash
+
+(F) You used an array where a hash was expected, but the array has no
+information on how to map from keys to array indices. You can do that
+only with arrays that have a hash reference at index 0.
+
+=item Can't goto subroutine from an eval-string
+
+(F) The "goto subroutine" call can't be used to jump out of an eval "string".
+(You can use it to jump out of an eval {BLOCK}, but you probably don't want to.)
+
+=item Can't localize pseudo-hash element
+
+(F) You said something like C<< local $ar->{'key'} >>, where $ar is
+a reference to a pseudo-hash. That hasn't been implemented yet, but
+you can get a similar effect by localizing the corresponding array
+element directly: C<< local $ar->[$ar->[0]{'key'}] >>.
+
+=item Can't use %%! because Errno.pm is not available
+
+(F) The first time the %! hash is used, perl automatically loads the
+Errno.pm module. The Errno module is expected to tie the %! hash to
+provide symbolic names for C<$!> errno values.
+
+=item Cannot find an opnumber for "%s"
+
+(F) A string of a form C<CORE::word> was given to prototype(), but
+there is no builtin with the name C<word>.
+
+=item Character class syntax [. .] is reserved for future extensions
+
+(W) Within regular expression character classes ([]) the syntax beginning
+with "[." and ending with ".]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[." and ".\]".
+
+=item Character class syntax [: :] is reserved for future extensions
+
+(W) Within regular expression character classes ([]) the syntax beginning
+with "[:" and ending with ":]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[:" and ":\]".
+
+=item Character class syntax [= =] is reserved for future extensions
+
+(W) Within regular expression character classes ([]) the syntax
+beginning with "[=" and ending with "=]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[=" and "=\]".
+
+=item %s: Eval-group in insecure regular expression
+
+(F) Perl detected tainted data when trying to compile a regular expression
+that contains the C<(?{ ... })> zero-width assertion, which is unsafe.
+See L<perlre/(?{ code })>, and L<perlsec>.
+
+=item %s: Eval-group not allowed, use re 'eval'
+
+(F) A regular expression contained the C<(?{ ... })> zero-width assertion,
+but that construct is only allowed when the C<use re 'eval'> pragma is
+in effect. See L<perlre/(?{ code })>.
+
+=item %s: Eval-group not allowed at run time
+
+(F) Perl tried to compile a regular expression containing the C<(?{ ... })>
+zero-width assertion at run time, as it would when the pattern contains
+interpolated values. Since that is a security risk, it is not allowed.
+If you insist, you may still do this by explicitly building the pattern
+from an interpolated string at run time and using that in an eval().
+See L<perlre/(?{ code })>.
+
+=item Explicit blessing to '' (assuming package main)
+
+(W) You are blessing a reference to a zero length string. This has
+the effect of blessing the reference into the package main. This is
+usually not what you want. Consider providing a default target
+package, e.g. bless($ref, $p || 'MyPackage');
+
+=item Illegal hex digit ignored
+
+(W) You may have tried to use a character other than 0 - 9 or A - F in a
+hexadecimal number. Interpretation of the hexadecimal number stopped
+before the illegal character.
+
+=item No such array field
+
+(F) You tried to access an array as a hash, but the field name used is
+not defined. The hash at index 0 should map all valid field names to
+array indices for that to work.
+
+=item No such field "%s" in variable %s of type %s
+
+(F) You tried to access a field of a typed variable where the type
+does not know about the field name. The field names are looked up in
+the %FIELDS hash in the type package at compile time. The %FIELDS hash
+is usually set up with the 'fields' pragma.
+
+=item Out of memory during ridiculously large request
+
+(F) You can't allocate more than 2^31+"small amount" bytes. This error
+is most likely to be caused by a typo in the Perl program. e.g., C<$arr[time]>
+instead of C<$arr[$time]>.
+
+=item Range iterator outside integer range
+
+(F) One (or both) of the numeric arguments to the range operator ".."
+are outside the range which can be represented by integers internally.
+One possible workaround is to force Perl to use magical string
+increment by prepending "0" to your numbers.
+
+=item Recursive inheritance detected while looking for method '%s' %s
+
+(F) More than 100 levels of inheritance were encountered while invoking a
+method. Probably indicates an unintended loop in your inheritance hierarchy.
+
+=item Reference found where even-sized list expected
+
+(W) You gave a single reference where Perl was expecting a list with
+an even number of elements (for assignment to a hash). This
+usually means that you used the anon hash constructor when you meant
+to use parens. In any case, a hash requires key/value B<pairs>.
+
+ %hash = { one => 1, two => 2, }; # WRONG
+ %hash = [ qw/ an anon array / ]; # WRONG
+ %hash = ( one => 1, two => 2, ); # right
+ %hash = qw( one 1 two 2 ); # also fine
+
+=item Undefined value assigned to typeglob
+
+(W) An undefined value was assigned to a typeglob, a la C<*foo = undef>.
+This does nothing. It's possible that you really mean C<undef *foo>.
+
+=item Use of reserved word "%s" is deprecated
+
+(D) The indicated bareword is a reserved word. Future versions of perl
+may use it as a keyword, so you're better off either explicitly quoting
+the word in a manner appropriate for its context of use, or using a
+different name altogether. The warning can be suppressed for subroutine
+names by either adding a C<&> prefix, or using a package qualifier,
+e.g. C<&our()>, or C<Foo::our()>.
+
+=item perl: warning: Setting locale failed.
+
+(S) The whole warning message will look something like:
+
+ perl: warning: Setting locale failed.
+ perl: warning: Please check that your locale settings:
+ LC_ALL = "En_US",
+ LANG = (unset)
+ are supported and installed on your system.
+ perl: warning: Falling back to the standard locale ("C").
+
+Exactly what were the failed locale settings varies. In the above the
+settings were that the LC_ALL was "En_US" and the LANG had no value.
+This error means that Perl detected that you and/or your system
+administrator have set up the so-called variable system but Perl could
+not use those settings. This was not dead serious, fortunately: there
+is a "default locale" called "C" that Perl can and will use, the
+script will be run. Before you really fix the problem, however, you
+will get the same error message each time you run Perl. How to really
+fix the problem can be found in L<perllocale/"LOCALE PROBLEMS">.
+
+=back
+
+
+=head1 Obsolete Diagnostics
+
+=over 4
+
+=item Can't mktemp()
+
+(F) The mktemp() routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
+
+Removed because B<-e> doesn't use temporary files any more.
+
+=item Can't write to temp file for B<-e>: %s
+
+(F) The write routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
+
+Removed because B<-e> doesn't use temporary files any more.
+
+=item Cannot open temporary file
+
+(F) The create routine failed for some reason while trying to process
+a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
+
+Removed because B<-e> doesn't use temporary files any more.
+
+=item regexp too big
+
+(F) The current implementation of regular expressions uses shorts as
+address offsets within a string. Unfortunately this means that if
+the regular expression compiles to longer than 32767, it'll blow up.
+Usually when you want a regular expression this big, there is a better
+way to do it with multiple statements. See L<perlre>.
+
+=back
+
+=head1 Configuration Changes
+
+You can use "Configure -Uinstallusrbinperl" which causes installperl
+to skip installing perl also as /usr/bin/perl. This is useful if you
+prefer not to modify /usr/bin for some reason or another but harmful
+because many scripts assume to find Perl in /usr/bin/perl.
+
+=head1 BUGS
+
+If you find what you think is a bug, you might check the headers of
+recently posted articles in the comp.lang.perl.misc newsgroup.
+There may also be information at http://www.perl.com/perl/ , the Perl
+Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Make sure you trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many contributions
+from The Perl Porters.
+
+Send omissions or corrections to <F<perlbug@perl.com>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod
new file mode 100644
index 00000000000..e93c316954a
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5100delta.pod
@@ -0,0 +1,1612 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5100delta - what is new for perl 5.10.0
+
+=head1 DESCRIPTION
+
+This document describes the differences between the 5.8.8 release and
+the 5.10.0 release.
+
+Many of the bug fixes in 5.10.0 were already seen in the 5.8.X maintenance
+releases; they are not duplicated here and are documented in the set of
+man pages named perl58[1-8]?delta.
+
+=head1 Core Enhancements
+
+=head2 The C<feature> pragma
+
+The C<feature> pragma is used to enable new syntax that would break Perl's
+backwards-compatibility with older releases of the language. It's a lexical
+pragma, like C<strict> or C<warnings>.
+
+Currently the following new features are available: C<switch> (adds a
+switch statement), C<say> (adds a C<say> built-in function), and C<state>
+(adds a C<state> keyword for declaring "static" variables). Those
+features are described in their own sections of this document.
+
+The C<feature> pragma is also implicitly loaded when you require a minimal
+perl version (with the C<use VERSION> construct) greater than, or equal
+to, 5.9.5. See L<feature> for details.
+
+=head2 New B<-E> command-line switch
+
+B<-E> is equivalent to B<-e>, but it implicitly enables all
+optional features (like C<use feature ":5.10">).
+
+=head2 Defined-or operator
+
+A new operator C<//> (defined-or) has been implemented.
+The following expression:
+
+ $a // $b
+
+is merely equivalent to
+
+ defined $a ? $a : $b
+
+and the statement
+
+ $c //= $d;
+
+can now be used instead of
+
+ $c = $d unless defined $c;
+
+The C<//> operator has the same precedence and associativity as C<||>.
+Special care has been taken to ensure that this operator Do What You Mean
+while not breaking old code, but some edge cases involving the empty
+regular expression may now parse differently. See L<perlop> for
+details.
+
+=head2 Switch and Smart Match operator
+
+Perl 5 now has a switch statement. It's available when C<use feature
+'switch'> is in effect. This feature introduces three new keywords,
+C<given>, C<when>, and C<default>:
+
+ given ($foo) {
+ when (/^abc/) { $abc = 1; }
+ when (/^def/) { $def = 1; }
+ when (/^xyz/) { $xyz = 1; }
+ default { $nothing = 1; }
+ }
+
+A more complete description of how Perl matches the switch variable
+against the C<when> conditions is given in L<perlsyn/"Switch statements">.
+
+This kind of match is called I<smart match>, and it's also possible to use
+it outside of switch statements, via the new C<~~> operator. See
+L<perlsyn/"Smart matching in detail">.
+
+This feature was contributed by Robin Houston.
+
+=head2 Regular expressions
+
+=over 4
+
+=item Recursive Patterns
+
+It is now possible to write recursive patterns without using the C<(??{})>
+construct. This new way is more efficient, and in many cases easier to
+read.
+
+Each capturing parenthesis can now be treated as an independent pattern
+that can be entered by using the C<(?PARNO)> syntax (C<PARNO> standing for
+"parenthesis number"). For example, the following pattern will match
+nested balanced angle brackets:
+
+ /
+ ^ # start of line
+ ( # start capture buffer 1
+ < # match an opening angle bracket
+ (?: # match one of:
+ (?> # don't backtrack over the inside of this group
+ [^<>]+ # one or more non angle brackets
+ ) # end non backtracking group
+ | # ... or ...
+ (?1) # recurse to bracket 1 and try it again
+ )* # 0 or more times.
+ > # match a closing angle bracket
+ ) # end capture buffer one
+ $ # end of line
+ /x
+
+PCRE users should note that Perl's recursive regex feature allows
+backtracking into a recursed pattern, whereas in PCRE the recursion is
+atomic or "possessive" in nature. As in the example above, you can
+add (?>) to control this selectively. (Yves Orton)
+
+=item Named Capture Buffers
+
+It is now possible to name capturing parenthesis in a pattern and refer to
+the captured contents by name. The naming syntax is C<< (?<NAME>....) >>.
+It's possible to backreference to a named buffer with the C<< \k<NAME> >>
+syntax. In code, the new magical hashes C<%+> and C<%-> can be used to
+access the contents of the capture buffers.
+
+Thus, to replace all doubled chars with a single copy, one could write
+
+ s/(?<letter>.)\k<letter>/$+{letter}/g
+
+Only buffers with defined contents will be "visible" in the C<%+> hash, so
+it's possible to do something like
+
+ foreach my $name (keys %+) {
+ print "content of buffer '$name' is $+{$name}\n";
+ }
+
+The C<%-> hash is a bit more complete, since it will contain array refs
+holding values from all capture buffers similarly named, if there should
+be many of them.
+
+C<%+> and C<%-> are implemented as tied hashes through the new module
+C<Tie::Hash::NamedCapture>.
+
+Users exposed to the .NET regex engine will find that the perl
+implementation differs in that the numerical ordering of the buffers
+is sequential, and not "unnamed first, then named". Thus in the pattern
+
+ /(A)(?<B>B)(C)(?<D>D)/
+
+$1 will be 'A', $2 will be 'B', $3 will be 'C' and $4 will be 'D' and not
+$1 is 'A', $2 is 'C' and $3 is 'B' and $4 is 'D' that a .NET programmer
+would expect. This is considered a feature. :-) (Yves Orton)
+
+=item Possessive Quantifiers
+
+Perl now supports the "possessive quantifier" syntax of the "atomic match"
+pattern. Basically a possessive quantifier matches as much as it can and never
+gives any back. Thus it can be used to control backtracking. The syntax is
+similar to non-greedy matching, except instead of using a '?' as the modifier
+the '+' is used. Thus C<?+>, C<*+>, C<++>, C<{min,max}+> are now legal
+quantifiers. (Yves Orton)
+
+=item Backtracking control verbs
+
+The regex engine now supports a number of special-purpose backtrack
+control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT), (*FAIL)
+and (*ACCEPT). See L<perlre> for their descriptions. (Yves Orton)
+
+=item Relative backreferences
+
+A new syntax C<\g{N}> or C<\gN> where "N" is a decimal integer allows a
+safer form of back-reference notation as well as allowing relative
+backreferences. This should make it easier to generate and embed patterns
+that contain backreferences. See L<perlre/"Capture buffers">. (Yves Orton)
+
+=item C<\K> escape
+
+The functionality of Jeff Pinyan's module Regexp::Keep has been added to
+the core. In regular expressions you can now use the special escape C<\K>
+as a way to do something like floating length positive lookbehind. It is
+also useful in substitutions like:
+
+ s/(foo)bar/$1/g
+
+that can now be converted to
+
+ s/foo\Kbar//g
+
+which is much more efficient. (Yves Orton)
+
+=item Vertical and horizontal whitespace, and linebreak
+
+Regular expressions now recognize the C<\v> and C<\h> escapes that match
+vertical and horizontal whitespace, respectively. C<\V> and C<\H>
+logically match their complements.
+
+C<\R> matches a generic linebreak, that is, vertical whitespace, plus
+the multi-character sequence C<"\x0D\x0A">.
+
+=back
+
+=head2 C<say()>
+
+say() is a new built-in, only available when C<use feature 'say'> is in
+effect, that is similar to print(), but that implicitly appends a newline
+to the printed string. See L<perlfunc/say>. (Robin Houston)
+
+=head2 Lexical C<$_>
+
+The default variable C<$_> can now be lexicalized, by declaring it like
+any other lexical variable, with a simple
+
+ my $_;
+
+The operations that default on C<$_> will use the lexically-scoped
+version of C<$_> when it exists, instead of the global C<$_>.
+
+In a C<map> or a C<grep> block, if C<$_> was previously my'ed, then the
+C<$_> inside the block is lexical as well (and scoped to the block).
+
+In a scope where C<$_> has been lexicalized, you can still have access to
+the global version of C<$_> by using C<$::_>, or, more simply, by
+overriding the lexical declaration with C<our $_>. (Rafael Garcia-Suarez)
+
+=head2 The C<_> prototype
+
+A new prototype character has been added. C<_> is equivalent to C<$> but
+defaults to C<$_> if the corresponding argument isn't supplied (both C<$>
+and C<_> denote a scalar). Due to the optional nature of the argument,
+you can only use it at the end of a prototype, or before a semicolon.
+
+This has a small incompatible consequence: the prototype() function has
+been adjusted to return C<_> for some built-ins in appropriate cases (for
+example, C<prototype('CORE::rmdir')>). (Rafael Garcia-Suarez)
+
+=head2 UNITCHECK blocks
+
+C<UNITCHECK>, a new special code block has been introduced, in addition to
+C<BEGIN>, C<CHECK>, C<INIT> and C<END>.
+
+C<CHECK> and C<INIT> blocks, while useful for some specialized purposes,
+are always executed at the transition between the compilation and the
+execution of the main program, and thus are useless whenever code is
+loaded at runtime. On the other hand, C<UNITCHECK> blocks are executed
+just after the unit which defined them has been compiled. See L<perlmod>
+for more information. (Alex Gough)
+
+=head2 New Pragma, C<mro>
+
+A new pragma, C<mro> (for Method Resolution Order) has been added. It
+permits to switch, on a per-class basis, the algorithm that perl uses to
+find inherited methods in case of a multiple inheritance hierarchy. The
+default MRO hasn't changed (DFS, for Depth First Search). Another MRO is
+available: the C3 algorithm. See L<mro> for more information.
+(Brandon Black)
+
+Note that, due to changes in the implementation of class hierarchy search,
+code that used to undef the C<*ISA> glob will most probably break. Anyway,
+undef'ing C<*ISA> had the side-effect of removing the magic on the @ISA
+array and should not have been done in the first place. Also, the
+cache C<*::ISA::CACHE::> no longer exists; to force reset the @ISA cache,
+you now need to use the C<mro> API, or more simply to assign to @ISA
+(e.g. with C<@ISA = @ISA>).
+
+=head2 readdir() may return a "short filename" on Windows
+
+The readdir() function may return a "short filename" when the long
+filename contains characters outside the ANSI codepage. Similarly
+Cwd::cwd() may return a short directory name, and glob() may return short
+names as well. On the NTFS file system these short names can always be
+represented in the ANSI codepage. This will not be true for all other file
+system drivers; e.g. the FAT filesystem stores short filenames in the OEM
+codepage, so some files on FAT volumes remain unaccessible through the
+ANSI APIs.
+
+Similarly, $^X, @INC, and $ENV{PATH} are preprocessed at startup to make
+sure all paths are valid in the ANSI codepage (if possible).
+
+The Win32::GetLongPathName() function now returns the UTF-8 encoded
+correct long file name instead of using replacement characters to force
+the name into the ANSI codepage. The new Win32::GetANSIPathName()
+function can be used to turn a long pathname into a short one only if the
+long one cannot be represented in the ANSI codepage.
+
+Many other functions in the C<Win32> module have been improved to accept
+UTF-8 encoded arguments. Please see L<Win32> for details.
+
+=head2 readpipe() is now overridable
+
+The built-in function readpipe() is now overridable. Overriding it permits
+also to override its operator counterpart, C<qx//> (a.k.a. C<``>).
+Moreover, it now defaults to C<$_> if no argument is provided. (Rafael
+Garcia-Suarez)
+
+=head2 Default argument for readline()
+
+readline() now defaults to C<*ARGV> if no argument is provided. (Rafael
+Garcia-Suarez)
+
+=head2 state() variables
+
+A new class of variables has been introduced. State variables are similar
+to C<my> variables, but are declared with the C<state> keyword in place of
+C<my>. They're visible only in their lexical scope, but their value is
+persistent: unlike C<my> variables, they're not undefined at scope entry,
+but retain their previous value. (Rafael Garcia-Suarez, Nicholas Clark)
+
+To use state variables, one needs to enable them by using
+
+ use feature 'state';
+
+or by using the C<-E> command-line switch in one-liners.
+See L<perlsub/"Persistent Private Variables">.
+
+=head2 Stacked filetest operators
+
+As a new form of syntactic sugar, it's now possible to stack up filetest
+operators. You can now write C<-f -w -x $file> in a row to mean
+C<-x $file && -w _ && -f _>. See L<perlfunc/-X>.
+
+=head2 UNIVERSAL::DOES()
+
+The C<UNIVERSAL> class has a new method, C<DOES()>. It has been added to
+solve semantic problems with the C<isa()> method. C<isa()> checks for
+inheritance, while C<DOES()> has been designed to be overridden when
+module authors use other types of relations between classes (in addition
+to inheritance). (chromatic)
+
+See L<< UNIVERSAL/"$obj->DOES( ROLE )" >>.
+
+=head2 Formats
+
+Formats were improved in several ways. A new field, C<^*>, can be used for
+variable-width, one-line-at-a-time text. Null characters are now handled
+correctly in picture lines. Using C<@#> and C<~~> together will now
+produce a compile-time error, as those format fields are incompatible.
+L<perlform> has been improved, and miscellaneous bugs fixed.
+
+=head2 Byte-order modifiers for pack() and unpack()
+
+There are two new byte-order modifiers, C<E<gt>> (big-endian) and C<E<lt>>
+(little-endian), that can be appended to most pack() and unpack() template
+characters and groups to force a certain byte-order for that type or group.
+See L<perlfunc/pack> and L<perlpacktut> for details.
+
+=head2 C<no VERSION>
+
+You can now use C<no> followed by a version number to specify that you
+want to use a version of perl older than the specified one.
+
+=head2 C<chdir>, C<chmod> and C<chown> on filehandles
+
+C<chdir>, C<chmod> and C<chown> can now work on filehandles as well as
+filenames, if the system supports respectively C<fchdir>, C<fchmod> and
+C<fchown>, thanks to a patch provided by Gisle Aas.
+
+=head2 OS groups
+
+C<$(> and C<$)> now return groups in the order where the OS returns them,
+thanks to Gisle Aas. This wasn't previously the case.
+
+=head2 Recursive sort subs
+
+You can now use recursive subroutines with sort(), thanks to Robin Houston.
+
+=head2 Exceptions in constant folding
+
+The constant folding routine is now wrapped in an exception handler, and
+if folding throws an exception (such as attempting to evaluate 0/0), perl
+now retains the current optree, rather than aborting the whole program.
+Without this change, programs would not compile if they had expressions that
+happened to generate exceptions, even though those expressions were in code
+that could never be reached at runtime. (Nicholas Clark, Dave Mitchell)
+
+=head2 Source filters in @INC
+
+It's possible to enhance the mechanism of subroutine hooks in @INC by
+adding a source filter on top of the filehandle opened and returned by the
+hook. This feature was planned a long time ago, but wasn't quite working
+until now. See L<perlfunc/require> for details. (Nicholas Clark)
+
+=head2 New internal variables
+
+=over 4
+
+=item C<${^RE_DEBUG_FLAGS}>
+
+This variable controls what debug flags are in effect for the regular
+expression engine when running under C<use re "debug">. See L<re> for
+details.
+
+=item C<${^CHILD_ERROR_NATIVE}>
+
+This variable gives the native status returned by the last pipe close,
+backtick command, successful call to wait() or waitpid(), or from the
+system() operator. See L<perlvar> for details. (Contributed by Gisle Aas.)
+
+=item C<${^RE_TRIE_MAXBUF}>
+
+See L</"Trie optimisation of literal string alternations">.
+
+=item C<${^WIN32_SLOPPY_STAT}>
+
+See L</"Sloppy stat on Windows">.
+
+=back
+
+=head2 Miscellaneous
+
+C<unpack()> now defaults to unpacking the C<$_> variable.
+
+C<mkdir()> without arguments now defaults to C<$_>.
+
+The internal dump output has been improved, so that non-printable characters
+such as newline and backspace are output in C<\x> notation, rather than
+octal.
+
+The B<-C> option can no longer be used on the C<#!> line. It wasn't
+working there anyway, since the standard streams are already set up
+at this point in the execution of the perl interpreter. You can use
+binmode() instead to get the desired behaviour.
+
+=head2 UCD 5.0.0
+
+The copy of the Unicode Character Database included in Perl 5 has
+been updated to version 5.0.0.
+
+=head2 MAD
+
+MAD, which stands for I<Miscellaneous Attribute Decoration>, is a
+still-in-development work leading to a Perl 5 to Perl 6 converter. To
+enable it, it's necessary to pass the argument C<-Dmad> to Configure. The
+obtained perl isn't binary compatible with a regular perl 5.10, and has
+space and speed penalties; moreover not all regression tests still pass
+with it. (Larry Wall, Nicholas Clark)
+
+=head2 kill() on Windows
+
+On Windows platforms, C<kill(-9, $pid)> now kills a process tree.
+(On Unix, this delivers the signal to all processes in the same process
+group.)
+
+=head1 Incompatible Changes
+
+=head2 Packing and UTF-8 strings
+
+The semantics of pack() and unpack() regarding UTF-8-encoded data has been
+changed. Processing is now by default character per character instead of
+byte per byte on the underlying encoding. Notably, code that used things
+like C<pack("a*", $string)> to see through the encoding of string will now
+simply get back the original $string. Packed strings can also get upgraded
+during processing when you store upgraded characters. You can get the old
+behaviour by using C<use bytes>.
+
+To be consistent with pack(), the C<C0> in unpack() templates indicates
+that the data is to be processed in character mode, i.e. character by
+character; on the contrary, C<U0> in unpack() indicates UTF-8 mode, where
+the packed string is processed in its UTF-8-encoded Unicode form on a byte
+by byte basis. This is reversed with regard to perl 5.8.X, but now consistent
+between pack() and unpack().
+
+Moreover, C<C0> and C<U0> can also be used in pack() templates to specify
+respectively character and byte modes.
+
+C<C0> and C<U0> in the middle of a pack or unpack format now switch to the
+specified encoding mode, honoring parens grouping. Previously, parens were
+ignored.
+
+Also, there is a new pack() character format, C<W>, which is intended to
+replace the old C<C>. C<C> is kept for unsigned chars coded as bytes in
+the strings internal representation. C<W> represents unsigned (logical)
+character values, which can be greater than 255. It is therefore more
+robust when dealing with potentially UTF-8-encoded data (as C<C> will wrap
+values outside the range 0..255, and not respect the string encoding).
+
+In practice, that means that pack formats are now encoding-neutral, except
+C<C>.
+
+For consistency, C<A> in unpack() format now trims all Unicode whitespace
+from the end of the string. Before perl 5.9.2, it used to strip only the
+classical ASCII space characters.
+
+=head2 Byte/character count feature in unpack()
+
+A new unpack() template character, C<".">, returns the number of bytes or
+characters (depending on the selected encoding mode, see above) read so far.
+
+=head2 The C<$*> and C<$#> variables have been removed
+
+C<$*>, which was deprecated in favor of the C</s> and C</m> regexp
+modifiers, has been removed.
+
+The deprecated C<$#> variable (output format for numbers) has been
+removed.
+
+Two new severe warnings, C<$#/$* is no longer supported>, have been added.
+
+=head2 substr() lvalues are no longer fixed-length
+
+The lvalues returned by the three argument form of substr() used to be a
+"fixed length window" on the original string. In some cases this could
+cause surprising action at distance or other undefined behaviour. Now the
+length of the window adjusts itself to the length of the string assigned to
+it.
+
+=head2 Parsing of C<-f _>
+
+The identifier C<_> is now forced to be a bareword after a filetest
+operator. This solves a number of misparsing issues when a global C<_>
+subroutine is defined.
+
+=head2 C<:unique>
+
+The C<:unique> attribute has been made a no-op, since its current
+implementation was fundamentally flawed and not threadsafe.
+
+=head2 Effect of pragmas in eval
+
+The compile-time value of the C<%^H> hint variable can now propagate into
+eval("")uated code. This makes it more useful to implement lexical
+pragmas.
+
+As a side-effect of this, the overloaded-ness of constants now propagates
+into eval("").
+
+=head2 chdir FOO
+
+A bareword argument to chdir() is now recognized as a file handle.
+Earlier releases interpreted the bareword as a directory name.
+(Gisle Aas)
+
+=head2 Handling of .pmc files
+
+An old feature of perl was that before C<require> or C<use> look for a
+file with a F<.pm> extension, they will first look for a similar filename
+with a F<.pmc> extension. If this file is found, it will be loaded in
+place of any potentially existing file ending in a F<.pm> extension.
+
+Previously, F<.pmc> files were loaded only if more recent than the
+matching F<.pm> file. Starting with 5.9.4, they'll be always loaded if
+they exist.
+
+=head2 $^V is now a C<version> object instead of a v-string
+
+$^V can still be used with the C<%vd> format in printf, but any
+character-level operations will now access the string representation
+of the C<version> object and not the ordinals of a v-string.
+Expressions like C<< substr($^V, 0, 2) >> or C<< split //, $^V >>
+no longer work and must be rewritten.
+
+=head2 @- and @+ in patterns
+
+The special arrays C<@-> and C<@+> are no longer interpolated in regular
+expressions. (Sadahiro Tomoyuki)
+
+=head2 $AUTOLOAD can now be tainted
+
+If you call a subroutine by a tainted name, and if it defers to an
+AUTOLOAD function, then $AUTOLOAD will be (correctly) tainted.
+(Rick Delaney)
+
+=head2 Tainting and printf
+
+When perl is run under taint mode, C<printf()> and C<sprintf()> will now
+reject any tainted format argument. (Rafael Garcia-Suarez)
+
+=head2 undef and signal handlers
+
+Undefining or deleting a signal handler via C<undef $SIG{FOO}> is now
+equivalent to setting it to C<'DEFAULT'>. (Rafael Garcia-Suarez)
+
+=head2 strictures and dereferencing in defined()
+
+C<use strict 'refs'> was ignoring taking a hard reference in an argument
+to defined(), as in :
+
+ use strict 'refs';
+ my $x = 'foo';
+ if (defined $$x) {...}
+
+This now correctly produces the run-time error C<Can't use string as a
+SCALAR ref while "strict refs" in use>.
+
+C<defined @$foo> and C<defined %$bar> are now also subject to C<strict
+'refs'> (that is, C<$foo> and C<$bar> shall be proper references there.)
+(C<defined(@foo)> and C<defined(%bar)> are discouraged constructs anyway.)
+(Nicholas Clark)
+
+=head2 C<(?p{})> has been removed
+
+The regular expression construct C<(?p{})>, which was deprecated in perl
+5.8, has been removed. Use C<(??{})> instead. (Rafael Garcia-Suarez)
+
+=head2 Pseudo-hashes have been removed
+
+Support for pseudo-hashes has been removed from Perl 5.9. (The C<fields>
+pragma remains here, but uses an alternate implementation.)
+
+=head2 Removal of the bytecode compiler and of perlcc
+
+C<perlcc>, the byteloader and the supporting modules (B::C, B::CC,
+B::Bytecode, etc.) are no longer distributed with the perl sources. Those
+experimental tools have never worked reliably, and, due to the lack of
+volunteers to keep them in line with the perl interpreter developments, it
+was decided to remove them instead of shipping a broken version of those.
+The last version of those modules can be found with perl 5.9.4.
+
+However the B compiler framework stays supported in the perl core, as with
+the more useful modules it has permitted (among others, B::Deparse and
+B::Concise).
+
+=head2 Removal of the JPL
+
+The JPL (Java-Perl Lingo) has been removed from the perl sources tarball.
+
+=head2 Recursive inheritance detected earlier
+
+Perl will now immediately throw an exception if you modify any package's
+C<@ISA> in such a way that it would cause recursive inheritance.
+
+Previously, the exception would not occur until Perl attempted to make
+use of the recursive inheritance while resolving a method or doing a
+C<$foo-E<gt>isa($bar)> lookup.
+
+=head2 warnings::enabled and warnings::warnif changed to favor users of modules
+
+The behaviour in 5.10.x favors the person using the module;
+The behaviour in 5.8.x favors the module writer;
+
+Assume the following code:
+
+ main calls Foo::Bar::baz()
+ Foo::Bar inherits from Foo::Base
+ Foo::Bar::baz() calls Foo::Base::_bazbaz()
+ Foo::Base::_bazbaz() calls: warnings::warnif('substr', 'some warning
+message');
+
+On 5.8.x, the code warns when Foo::Bar contains C<use warnings;>
+It does not matter if Foo::Base or main have warnings enabled
+to disable the warning one has to modify Foo::Bar.
+
+On 5.10.0 and newer, the code warns when main contains C<use warnings;>
+It does not matter if Foo::Base or Foo::Bar have warnings enabled
+to disable the warning one has to modify main.
+
+=head1 Modules and Pragmata
+
+=head2 Upgrading individual core modules
+
+Even more core modules are now also available separately through the
+CPAN. If you wish to update one of these modules, you don't need to
+wait for a new perl release. From within the cpan shell, running the
+'r' command will report on modules with upgrades available. See
+C<perldoc CPAN> for more information.
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<feature>
+
+The new pragma C<feature> is used to enable new features that might break
+old code. See L</"The C<feature> pragma"> above.
+
+=item C<mro>
+
+This new pragma enables to change the algorithm used to resolve inherited
+methods. See L</"New Pragma, C<mro>"> above.
+
+=item Scoping of the C<sort> pragma
+
+The C<sort> pragma is now lexically scoped. Its effect used to be global.
+
+=item Scoping of C<bignum>, C<bigint>, C<bigrat>
+
+The three numeric pragmas C<bignum>, C<bigint> and C<bigrat> are now
+lexically scoped. (Tels)
+
+=item C<base>
+
+The C<base> pragma now warns if a class tries to inherit from itself.
+(Curtis "Ovid" Poe)
+
+=item C<strict> and C<warnings>
+
+C<strict> and C<warnings> will now complain loudly if they are loaded via
+incorrect casing (as in C<use Strict;>). (Johan Vromans)
+
+=item C<version>
+
+The C<version> module provides support for version objects.
+
+=item C<warnings>
+
+The C<warnings> pragma doesn't load C<Carp> anymore. That means that code
+that used C<Carp> routines without having loaded it at compile time might
+need to be adjusted; typically, the following (faulty) code won't work
+anymore, and will require parentheses to be added after the function name:
+
+ use warnings;
+ require Carp;
+ Carp::confess 'argh';
+
+=item C<less>
+
+C<less> now does something useful (or at least it tries to). In fact, it
+has been turned into a lexical pragma. So, in your modules, you can now
+test whether your users have requested to use less CPU, or less memory,
+less magic, or maybe even less fat. See L<less> for more. (Joshua ben
+Jore)
+
+=back
+
+=head2 New modules
+
+=over 4
+
+=item *
+
+C<encoding::warnings>, by Audrey Tang, is a module to emit warnings
+whenever an ASCII character string containing high-bit bytes is implicitly
+converted into UTF-8. It's a lexical pragma since Perl 5.9.4; on older
+perls, its effect is global.
+
+=item *
+
+C<Module::CoreList>, by Richard Clamp, is a small handy module that tells
+you what versions of core modules ship with any versions of Perl 5. It
+comes with a command-line frontend, C<corelist>.
+
+=item *
+
+C<Math::BigInt::FastCalc> is an XS-enabled, and thus faster, version of
+C<Math::BigInt::Calc>.
+
+=item *
+
+C<Compress::Zlib> is an interface to the zlib compression library. It
+comes with a bundled version of zlib, so having a working zlib is not a
+prerequisite to install it. It's used by C<Archive::Tar> (see below).
+
+=item *
+
+C<IO::Zlib> is an C<IO::>-style interface to C<Compress::Zlib>.
+
+=item *
+
+C<Archive::Tar> is a module to manipulate C<tar> archives.
+
+=item *
+
+C<Digest::SHA> is a module used to calculate many types of SHA digests,
+has been included for SHA support in the CPAN module.
+
+=item *
+
+C<ExtUtils::CBuilder> and C<ExtUtils::ParseXS> have been added.
+
+=item *
+
+C<Hash::Util::FieldHash>, by Anno Siegel, has been added. This module
+provides support for I<field hashes>: hashes that maintain an association
+of a reference with a value, in a thread-safe garbage-collected way.
+Such hashes are useful to implement inside-out objects.
+
+=item *
+
+C<Module::Build>, by Ken Williams, has been added. It's an alternative to
+C<ExtUtils::MakeMaker> to build and install perl modules.
+
+=item *
+
+C<Module::Load>, by Jos Boumans, has been added. It provides a single
+interface to load Perl modules and F<.pl> files.
+
+=item *
+
+C<Module::Loaded>, by Jos Boumans, has been added. It's used to mark
+modules as loaded or unloaded.
+
+=item *
+
+C<Package::Constants>, by Jos Boumans, has been added. It's a simple
+helper to list all constants declared in a given package.
+
+=item *
+
+C<Win32API::File>, by Tye McQueen, has been added (for Windows builds).
+This module provides low-level access to Win32 system API calls for
+files/dirs.
+
+=item *
+
+C<Locale::Maketext::Simple>, needed by CPANPLUS, is a simple wrapper around
+C<Locale::Maketext::Lexicon>. Note that C<Locale::Maketext::Lexicon> isn't
+included in the perl core; the behaviour of C<Locale::Maketext::Simple>
+gracefully degrades when the later isn't present.
+
+=item *
+
+C<Params::Check> implements a generic input parsing/checking mechanism. It
+is used by CPANPLUS.
+
+=item *
+
+C<Term::UI> simplifies the task to ask questions at a terminal prompt.
+
+=item *
+
+C<Object::Accessor> provides an interface to create per-object accessors.
+
+=item *
+
+C<Module::Pluggable> is a simple framework to create modules that accept
+pluggable sub-modules.
+
+=item *
+
+C<Module::Load::Conditional> provides simple ways to query and possibly
+load installed modules.
+
+=item *
+
+C<Time::Piece> provides an object oriented interface to time functions,
+overriding the built-ins localtime() and gmtime().
+
+=item *
+
+C<IPC::Cmd> helps to find and run external commands, possibly
+interactively.
+
+=item *
+
+C<File::Fetch> provide a simple generic file fetching mechanism.
+
+=item *
+
+C<Log::Message> and C<Log::Message::Simple> are used by the log facility
+of C<CPANPLUS>.
+
+=item *
+
+C<Archive::Extract> is a generic archive extraction mechanism
+for F<.tar> (plain, gziped or bzipped) or F<.zip> files.
+
+=item *
+
+C<CPANPLUS> provides an API and a command-line tool to access the CPAN
+mirrors.
+
+=item *
+
+C<Pod::Escapes> provides utilities that are useful in decoding Pod
+EE<lt>...E<gt> sequences.
+
+=item *
+
+C<Pod::Simple> is now the backend for several of the Pod-related modules
+included with Perl.
+
+=back
+
+=head2 Selected Changes to Core Modules
+
+=over 4
+
+=item C<Attribute::Handlers>
+
+C<Attribute::Handlers> can now report the caller's file and line number.
+(David Feldman)
+
+All interpreted attributes are now passed as array references. (Damian
+Conway)
+
+=item C<B::Lint>
+
+C<B::Lint> is now based on C<Module::Pluggable>, and so can be extended
+with plugins. (Joshua ben Jore)
+
+=item C<B>
+
+It's now possible to access the lexical pragma hints (C<%^H>) by using the
+method B::COP::hints_hash(). It returns a C<B::RHE> object, which in turn
+can be used to get a hash reference via the method B::RHE::HASH(). (Joshua
+ben Jore)
+
+=item C<Thread>
+
+As the old 5005thread threading model has been removed, in favor of the
+ithreads scheme, the C<Thread> module is now a compatibility wrapper, to
+be used in old code only. It has been removed from the default list of
+dynamic extensions.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item perl -d
+
+The Perl debugger can now save all debugger commands for sourcing later;
+notably, it can now emulate stepping backwards, by restarting and
+rerunning all bar the last command from a saved command history.
+
+It can also display the parent inheritance tree of a given class, with the
+C<i> command.
+
+=item ptar
+
+C<ptar> is a pure perl implementation of C<tar> that comes with
+C<Archive::Tar>.
+
+=item ptardiff
+
+C<ptardiff> is a small utility used to generate a diff between the contents
+of a tar archive and a directory tree. Like C<ptar>, it comes with
+C<Archive::Tar>.
+
+=item shasum
+
+C<shasum> is a command-line utility, used to print or to check SHA
+digests. It comes with the new C<Digest::SHA> module.
+
+=item corelist
+
+The C<corelist> utility is now installed with perl (see L</"New modules">
+above).
+
+=item h2ph and h2xs
+
+C<h2ph> and C<h2xs> have been made more robust with regard to
+"modern" C code.
+
+C<h2xs> implements a new option C<--use-xsloader> to force use of
+C<XSLoader> even in backwards compatible modules.
+
+The handling of authors' names that had apostrophes has been fixed.
+
+Any enums with negative values are now skipped.
+
+=item perlivp
+
+C<perlivp> no longer checks for F<*.ph> files by default. Use the new C<-a>
+option to run I<all> tests.
+
+=item find2perl
+
+C<find2perl> now assumes C<-print> as a default action. Previously, it
+needed to be specified explicitly.
+
+Several bugs have been fixed in C<find2perl>, regarding C<-exec> and
+C<-eval>. Also the options C<-path>, C<-ipath> and C<-iname> have been
+added.
+
+=item config_data
+
+C<config_data> is a new utility that comes with C<Module::Build>. It
+provides a command-line interface to the configuration of Perl modules
+that use Module::Build's framework of configurability (that is,
+C<*::ConfigData> modules that contain local configuration information for
+their parent modules.)
+
+=item cpanp
+
+C<cpanp>, the CPANPLUS shell, has been added. (C<cpanp-run-perl>, a
+helper for CPANPLUS operation, has been added too, but isn't intended for
+direct use).
+
+=item cpan2dist
+
+C<cpan2dist> is a new utility that comes with CPANPLUS. It's a tool to
+create distributions (or packages) from CPAN modules.
+
+=item pod2html
+
+The output of C<pod2html> has been enhanced to be more customizable via
+CSS. Some formatting problems were also corrected. (Jari Aalto)
+
+=back
+
+=head1 New Documentation
+
+The L<perlpragma> manpage documents how to write one's own lexical
+pragmas in pure Perl (something that is possible starting with 5.9.4).
+
+The new L<perlglossary> manpage is a glossary of terms used in the Perl
+documentation, technical and otherwise, kindly provided by O'Reilly Media,
+Inc.
+
+The L<perlreguts> manpage, courtesy of Yves Orton, describes internals of the
+Perl regular expression engine.
+
+The L<perlreapi> manpage describes the interface to the perl interpreter
+used to write pluggable regular expression engines (by Ævar Arnfjörð
+Bjarmason).
+
+The L<perlunitut> manpage is an tutorial for programming with Unicode and
+string encodings in Perl, courtesy of Juerd Waalboer.
+
+A new manual page, L<perlunifaq> (the Perl Unicode FAQ), has been added
+(Juerd Waalboer).
+
+The L<perlcommunity> manpage gives a description of the Perl community
+on the Internet and in real life. (Edgar "Trizor" Bering)
+
+The L<CORE> manual page documents the C<CORE::> namespace. (Tels)
+
+The long-existing feature of C</(?{...})/> regexps setting C<$_> and pos()
+is now documented.
+
+=head1 Performance Enhancements
+
+=head2 In-place sorting
+
+Sorting arrays in place (C<@a = sort @a>) is now optimized to avoid
+making a temporary copy of the array.
+
+Likewise, C<reverse sort ...> is now optimized to sort in reverse,
+avoiding the generation of a temporary intermediate list.
+
+=head2 Lexical array access
+
+Access to elements of lexical arrays via a numeric constant between 0 and
+255 is now faster. (This used to be only the case for global arrays.)
+
+=head2 XS-assisted SWASHGET
+
+Some pure-perl code that perl was using to retrieve Unicode properties and
+transliteration mappings has been reimplemented in XS.
+
+=head2 Constant subroutines
+
+The interpreter internals now support a far more memory efficient form of
+inlineable constants. Storing a reference to a constant value in a symbol
+table is equivalent to a full typeglob referencing a constant subroutine,
+but using about 400 bytes less memory. This proxy constant subroutine is
+automatically upgraded to a real typeglob with subroutine if necessary.
+The approach taken is analogous to the existing space optimisation for
+subroutine stub declarations, which are stored as plain scalars in place
+of the full typeglob.
+
+Several of the core modules have been converted to use this feature for
+their system dependent constants - as a result C<use POSIX;> now takes about
+200K less memory.
+
+=head2 C<PERL_DONT_CREATE_GVSV>
+
+The new compilation flag C<PERL_DONT_CREATE_GVSV>, introduced as an option
+in perl 5.8.8, is turned on by default in perl 5.9.3. It prevents perl
+from creating an empty scalar with every new typeglob. See L<perl589delta>
+for details.
+
+=head2 Weak references are cheaper
+
+Weak reference creation is now I<O(1)> rather than I<O(n)>, courtesy of
+Nicholas Clark. Weak reference deletion remains I<O(n)>, but if deletion only
+happens at program exit, it may be skipped completely.
+
+=head2 sort() enhancements
+
+Salvador Fandiño provided improvements to reduce the memory usage of C<sort>
+and to speed up some cases.
+
+=head2 Memory optimisations
+
+Several internal data structures (typeglobs, GVs, CVs, formats) have been
+restructured to use less memory. (Nicholas Clark)
+
+=head2 UTF-8 cache optimisation
+
+The UTF-8 caching code is now more efficient, and used more often.
+(Nicholas Clark)
+
+=head2 Sloppy stat on Windows
+
+On Windows, perl's stat() function normally opens the file to determine
+the link count and update attributes that may have been changed through
+hard links. Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up
+stat() by not performing this operation. (Jan Dubois)
+
+=head2 Regular expressions optimisations
+
+=over 4
+
+=item Engine de-recursivised
+
+The regular expression engine is no longer recursive, meaning that
+patterns that used to overflow the stack will either die with useful
+explanations, or run to completion, which, since they were able to blow
+the stack before, will likely take a very long time to happen. If you were
+experiencing the occasional stack overflow (or segfault) and upgrade to
+discover that now perl apparently hangs instead, look for a degenerate
+regex. (Dave Mitchell)
+
+=item Single char char-classes treated as literals
+
+Classes of a single character are now treated the same as if the character
+had been used as a literal, meaning that code that uses char-classes as an
+escaping mechanism will see a speedup. (Yves Orton)
+
+=item Trie optimisation of literal string alternations
+
+Alternations, where possible, are optimised into more efficient matching
+structures. String literal alternations are merged into a trie and are
+matched simultaneously. This means that instead of O(N) time for matching
+N alternations at a given point, the new code performs in O(1) time.
+A new special variable, ${^RE_TRIE_MAXBUF}, has been added to fine-tune
+this optimization. (Yves Orton)
+
+B<Note:> Much code exists that works around perl's historic poor
+performance on alternations. Often the tricks used to do so will disable
+the new optimisations. Hopefully the utility modules used for this purpose
+will be educated about these new optimisations.
+
+=item Aho-Corasick start-point optimisation
+
+When a pattern starts with a trie-able alternation and there aren't
+better optimisations available, the regex engine will use Aho-Corasick
+matching to find the start point. (Yves Orton)
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Configuration improvements
+
+=over 4
+
+=item C<-Dusesitecustomize>
+
+Run-time customization of @INC can be enabled by passing the
+C<-Dusesitecustomize> flag to Configure. When enabled, this will make perl
+run F<$sitelibexp/sitecustomize.pl> before anything else. This script can
+then be set up to add additional entries to @INC.
+
+=item Relocatable installations
+
+There is now Configure support for creating a relocatable perl tree. If
+you Configure with C<-Duserelocatableinc>, then the paths in @INC (and
+everything else in %Config) can be optionally located via the path of the
+perl executable.
+
+That means that, if the string C<".../"> is found at the start of any
+path, it's substituted with the directory of $^X. So, the relocation can
+be configured on a per-directory basis, although the default with
+C<-Duserelocatableinc> is that everything is relocated. The initial
+install is done to the original configured prefix.
+
+=item strlcat() and strlcpy()
+
+The configuration process now detects whether strlcat() and strlcpy() are
+available. When they are not available, perl's own version is used (from
+Russ Allbery's public domain implementation). Various places in the perl
+interpreter now use them. (Steve Peters)
+
+=item C<d_pseudofork> and C<d_printf_format_null>
+
+A new configuration variable, available as C<$Config{d_pseudofork}> in
+the L<Config> module, has been added, to distinguish real fork() support
+from fake pseudofork used on Windows platforms.
+
+A new configuration variable, C<d_printf_format_null>, has been added,
+to see if printf-like formats are allowed to be NULL.
+
+=item Configure help
+
+C<Configure -h> has been extended with the most commonly used options.
+
+=back
+
+=head2 Compilation improvements
+
+=over 4
+
+=item Parallel build
+
+Parallel makes should work properly now, although there may still be problems
+if C<make test> is instructed to run in parallel.
+
+=item Borland's compilers support
+
+Building with Borland's compilers on Win32 should work more smoothly. In
+particular Steve Hay has worked to side step many warnings emitted by their
+compilers and at least one C compiler internal error.
+
+=item Static build on Windows
+
+Perl extensions on Windows now can be statically built into the Perl DLL.
+
+Also, it's now possible to build a C<perl-static.exe> that doesn't depend
+on the Perl DLL on Win32. See the Win32 makefiles for details.
+(Vadim Konovalov)
+
+=item ppport.h files
+
+All F<ppport.h> files in the XS modules bundled with perl are now
+autogenerated at build time. (Marcus Holland-Moritz)
+
+=item C++ compatibility
+
+Efforts have been made to make perl and the core XS modules compilable
+with various C++ compilers (although the situation is not perfect with
+some of the compilers on some of the platforms tested.)
+
+=item Support for Microsoft 64-bit compiler
+
+Support for building perl with Microsoft's 64-bit compiler has been
+improved. (ActiveState)
+
+=item Visual C++
+
+Perl can now be compiled with Microsoft Visual C++ 2005 (and 2008 Beta 2).
+
+=item Win32 builds
+
+All win32 builds (MS-Win, WinCE) have been merged and cleaned up.
+
+=back
+
+=head2 Installation improvements
+
+=over 4
+
+=item Module auxiliary files
+
+README files and changelogs for CPAN modules bundled with perl are no
+longer installed.
+
+=back
+
+=head2 New Or Improved Platforms
+
+Perl has been reported to work on Symbian OS. See L<perlsymbian> for more
+information.
+
+Many improvements have been made towards making Perl work correctly on
+z/OS.
+
+Perl has been reported to work on DragonFlyBSD and MidnightBSD.
+
+Perl has also been reported to work on NexentaOS
+( http://www.gnusolaris.org/ ).
+
+The VMS port has been improved. See L<perlvms>.
+
+Support for Cray XT4 Catamount/Qk has been added. See
+F<hints/catamount.sh> in the source code distribution for more
+information.
+
+Vendor patches have been merged for RedHat and Gentoo.
+
+DynaLoader::dl_unload_file() now works on Windows.
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item strictures in regexp-eval blocks
+
+C<strict> wasn't in effect in regexp-eval blocks (C</(?{...})/>).
+
+=item Calling CORE::require()
+
+CORE::require() and CORE::do() were always parsed as require() and do()
+when they were overridden. This is now fixed.
+
+=item Subscripts of slices
+
+You can now use a non-arrowed form for chained subscripts after a list
+slice, like in:
+
+ ({foo => "bar"})[0]{foo}
+
+This used to be a syntax error; a C<< -> >> was required.
+
+=item C<no warnings 'category'> works correctly with -w
+
+Previously when running with warnings enabled globally via C<-w>, selective
+disabling of specific warning categories would actually turn off all warnings.
+This is now fixed; now C<no warnings 'io';> will only turn off warnings in the
+C<io> class. Previously it would erroneously turn off all warnings.
+
+=item threads improvements
+
+Several memory leaks in ithreads were closed. Also, ithreads were made
+less memory-intensive.
+
+C<threads> is now a dual-life module, also available on CPAN. It has been
+expanded in many ways. A kill() method is available for thread signalling.
+One can get thread status, or the list of running or joinable threads.
+
+A new C<< threads->exit() >> method is used to exit from the application
+(this is the default for the main thread) or from the current thread only
+(this is the default for all other threads). On the other hand, the exit()
+built-in now always causes the whole application to terminate. (Jerry
+D. Hedden)
+
+=item chr() and negative values
+
+chr() on a negative value now gives C<\x{FFFD}>, the Unicode replacement
+character, unless when the C<bytes> pragma is in effect, where the low
+eight bits of the value are used.
+
+=item PERL5SHELL and tainting
+
+On Windows, the PERL5SHELL environment variable is now checked for
+taintedness. (Rafael Garcia-Suarez)
+
+=item Using *FILE{IO}
+
+C<stat()> and C<-X> filetests now treat *FILE{IO} filehandles like *FILE
+filehandles. (Steve Peters)
+
+=item Overloading and reblessing
+
+Overloading now works when references are reblessed into another class.
+Internally, this has been implemented by moving the flag for "overloading"
+from the reference to the referent, which logically is where it should
+always have been. (Nicholas Clark)
+
+=item Overloading and UTF-8
+
+A few bugs related to UTF-8 handling with objects that have
+stringification overloaded have been fixed. (Nicholas Clark)
+
+=item eval memory leaks fixed
+
+Traditionally, C<eval 'syntax error'> has leaked badly. Many (but not all)
+of these leaks have now been eliminated or reduced. (Dave Mitchell)
+
+=item Random device on Windows
+
+In previous versions, perl would read the file F</dev/urandom> if it
+existed when seeding its random number generator. That file is unlikely
+to exist on Windows, and if it did would probably not contain appropriate
+data, so perl no longer tries to read it on Windows. (Alex Davies)
+
+=item PERLIO_DEBUG
+
+The C<PERLIO_DEBUG> environment variable no longer has any effect for
+setuid scripts and for scripts run with B<-T>.
+
+Moreover, with a thread-enabled perl, using C<PERLIO_DEBUG> could lead to
+an internal buffer overflow. This has been fixed.
+
+=item PerlIO::scalar and read-only scalars
+
+PerlIO::scalar will now prevent writing to read-only scalars. Moreover,
+seek() is now supported with PerlIO::scalar-based filehandles, the
+underlying string being zero-filled as needed. (Rafael, Jarkko Hietaniemi)
+
+=item study() and UTF-8
+
+study() never worked for UTF-8 strings, but could lead to false results.
+It's now a no-op on UTF-8 data. (Yves Orton)
+
+=item Critical signals
+
+The signals SIGILL, SIGBUS and SIGSEGV are now always delivered in an
+"unsafe" manner (contrary to other signals, that are deferred until the
+perl interpreter reaches a reasonably stable state; see
+L<perlipc/"Deferred Signals (Safe Signals)">). (Rafael)
+
+=item @INC-hook fix
+
+When a module or a file is loaded through an @INC-hook, and when this hook
+has set a filename entry in %INC, __FILE__ is now set for this module
+accordingly to the contents of that %INC entry. (Rafael)
+
+=item C<-t> switch fix
+
+The C<-w> and C<-t> switches can now be used together without messing
+up which categories of warnings are activated. (Rafael)
+
+=item Duping UTF-8 filehandles
+
+Duping a filehandle which has the C<:utf8> PerlIO layer set will now
+properly carry that layer on the duped filehandle. (Rafael)
+
+=item Localisation of hash elements
+
+Localizing a hash element whose key was given as a variable didn't work
+correctly if the variable was changed while the local() was in effect (as
+in C<local $h{$x}; ++$x>). (Bo Lindbergh)
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item Use of uninitialized value
+
+Perl will now try to tell you the name of the variable (if any) that was
+undefined.
+
+=item Deprecated use of my() in false conditional
+
+A new deprecation warning, I<Deprecated use of my() in false conditional>,
+has been added, to warn against the use of the dubious and deprecated
+construct
+
+ my $x if 0;
+
+See L<perldiag>. Use C<state> variables instead.
+
+=item !=~ should be !~
+
+A new warning, C<!=~ should be !~>, is emitted to prevent this misspelling
+of the non-matching operator.
+
+=item Newline in left-justified string
+
+The warning I<Newline in left-justified string> has been removed.
+
+=item Too late for "-T" option
+
+The error I<Too late for "-T" option> has been reformulated to be more
+descriptive.
+
+=item "%s" variable %s masks earlier declaration
+
+This warning is now emitted in more consistent cases; in short, when one
+of the declarations involved is a C<my> variable:
+
+ my $x; my $x; # warns
+ my $x; our $x; # warns
+ our $x; my $x; # warns
+
+On the other hand, the following:
+
+ our $x; our $x;
+
+now gives a C<"our" variable %s redeclared> warning.
+
+=item readdir()/closedir()/etc. attempted on invalid dirhandle
+
+These new warnings are now emitted when a dirhandle is used but is
+either closed or not really a dirhandle.
+
+=item Opening dirhandle/filehandle %s also as a file/directory
+
+Two deprecation warnings have been added: (Rafael)
+
+ Opening dirhandle %s also as a file
+ Opening filehandle %s also as a directory
+
+=item Use of -P is deprecated
+
+Perl's command-line switch C<-P> is now deprecated.
+
+=item v-string in use/require is non-portable
+
+Perl will warn you against potential backwards compatibility problems with
+the C<use VERSION> syntax.
+
+=item perl -V
+
+C<perl -V> has several improvements, making it more useable from shell
+scripts to get the value of configuration variables. See L<perlrun> for
+details.
+
+=back
+
+=head1 Changed Internals
+
+In general, the source code of perl has been refactored, tidied up,
+and optimized in many places. Also, memory management and allocation
+has been improved in several points.
+
+When compiling the perl core with gcc, as many gcc warning flags are
+turned on as is possible on the platform. (This quest for cleanliness
+doesn't extend to XS code because we cannot guarantee the tidiness of
+code we didn't write.) Similar strictness flags have been added or
+tightened for various other C compilers.
+
+=head2 Reordering of SVt_* constants
+
+The relative ordering of constants that define the various types of C<SV>
+have changed; in particular, C<SVt_PVGV> has been moved before C<SVt_PVLV>,
+C<SVt_PVAV>, C<SVt_PVHV> and C<SVt_PVCV>. This is unlikely to make any
+difference unless you have code that explicitly makes assumptions about that
+ordering. (The inheritance hierarchy of C<B::*> objects has been changed
+to reflect this.)
+
+=head2 Elimination of SVt_PVBM
+
+Related to this, the internal type C<SVt_PVBM> has been removed. This
+dedicated type of C<SV> was used by the C<index> operator and parts of the
+regexp engine to facilitate fast Boyer-Moore matches. Its use internally has
+been replaced by C<SV>s of type C<SVt_PVGV>.
+
+=head2 New type SVt_BIND
+
+A new type C<SVt_BIND> has been added, in readiness for the project to
+implement Perl 6 on 5. There deliberately is no implementation yet, and
+they cannot yet be created or destroyed.
+
+=head2 Removal of CPP symbols
+
+The C preprocessor symbols C<PERL_PM_APIVERSION> and
+C<PERL_XS_APIVERSION>, which were supposed to give the version number of
+the oldest perl binary-compatible (resp. source-compatible) with the
+present one, were not used, and sometimes had misleading values. They have
+been removed.
+
+=head2 Less space is used by ops
+
+The C<BASEOP> structure now uses less space. The C<op_seq> field has been
+removed and replaced by a single bit bit-field C<op_opt>. C<op_type> is now 9
+bits long. (Consequently, the C<B::OP> class doesn't provide an C<seq>
+method anymore.)
+
+=head2 New parser
+
+perl's parser is now generated by bison (it used to be generated by
+byacc.) As a result, it seems to be a bit more robust.
+
+Also, Dave Mitchell improved the lexer debugging output under C<-DT>.
+
+=head2 Use of C<const>
+
+Andy Lester supplied many improvements to determine which function
+parameters and local variables could actually be declared C<const> to the C
+compiler. Steve Peters provided new C<*_set> macros and reworked the core to
+use these rather than assigning to macros in LVALUE context.
+
+=head2 Mathoms
+
+A new file, F<mathoms.c>, has been added. It contains functions that are
+no longer used in the perl core, but that remain available for binary or
+source compatibility reasons. However, those functions will not be
+compiled in if you add C<-DNO_MATHOMS> in the compiler flags.
+
+=head2 C<AvFLAGS> has been removed
+
+The C<AvFLAGS> macro has been removed.
+
+=head2 C<av_*> changes
+
+The C<av_*()> functions, used to manipulate arrays, no longer accept null
+C<AV*> parameters.
+
+=head2 $^H and %^H
+
+The implementation of the special variables $^H and %^H has changed, to
+allow implementing lexical pragmas in pure Perl.
+
+=head2 B:: modules inheritance changed
+
+The inheritance hierarchy of C<B::> modules has changed; C<B::NV> now
+inherits from C<B::SV> (it used to inherit from C<B::IV>).
+
+=head2 Anonymous hash and array constructors
+
+The anonymous hash and array constructors now take 1 op in the optree
+instead of 3, now that pp_anonhash and pp_anonlist return a reference to
+an hash/array when the op is flagged with OPf_SPECIAL. (Nicholas Clark)
+
+=head1 Known Problems
+
+There's still a remaining problem in the implementation of the lexical
+C<$_>: it doesn't work inside C</(?{...})/> blocks. (See the TODO test in
+F<t/op/mydef.t>.)
+
+Stacked filetest operators won't work when the C<filetest> pragma is in
+effect, because they rely on the stat() buffer C<_> being populated, and
+filetest bypasses stat().
+
+=head2 UTF-8 problems
+
+The handling of Unicode still is unclean in several places, where it's
+dependent on whether a string is internally flagged as UTF-8. This will
+be made more consistent in perl 5.12, but that won't be possible without
+a certain amount of backwards incompatibility.
+
+=head1 Platform Specific Problems
+
+When compiled with g++ and thread support on Linux, it's reported that the
+C<$!> stops working correctly. This is related to the fact that the glibc
+provides two strerror_r(3) implementation, and perl selects the wrong
+one.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/rt3/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file and the perl590delta to perl595delta man pages for
+exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5101delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5101delta.pod
new file mode 100644
index 00000000000..c6cdef977ae
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5101delta.pod
@@ -0,0 +1,1772 @@
+=head1 NAME
+
+perl5101delta - what is new for perl v5.10.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.10.0 release and
+the 5.10.1 release.
+
+If you are upgrading from an earlier release such as 5.8.8, first read
+the L<perl5100delta>, which describes differences between 5.8.8 and
+5.10.0
+
+=head1 Incompatible Changes
+
+=head2 Switch statement changes
+
+The handling of complex expressions by the C<given>/C<when> switch
+statement has been enhanced. There are two new cases where C<when> now
+interprets its argument as a boolean, instead of an expression to be used
+in a smart match:
+
+=over 4
+
+=item flip-flop operators
+
+The C<..> and C<...> flip-flop operators are now evaluated in boolean
+context, following their usual semantics; see L<perlop/"Range Operators">.
+
+Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
+whether a given value is an integer between 1 and 10; you should use
+C<when ([1..10])> instead (note the array reference).
+
+However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
+context ensures it can now be useful in a C<when()>, notably for
+implementing bistable conditions, like in:
+
+ when (/^=begin/ .. /^=end/) {
+ # do something
+ }
+
+=item defined-or operator
+
+A compound expression involving the defined-or operator, as in
+C<when (expr1 // expr2)>, will be treated as boolean if the first
+expression is boolean. (This just extends the existing rule that applies
+to the regular or operator, as in C<when (expr1 || expr2)>.)
+
+=back
+
+The next section details more changes brought to the semantics to
+the smart match operator, that naturally also modify the behaviour
+of the switch statements where smart matching is implicitly used.
+
+=head2 Smart match changes
+
+=head3 Changes to type-based dispatch
+
+The smart match operator C<~~> is no longer commutative. The behaviour of
+a smart match now depends primarily on the type of its right hand
+argument. Moreover, its semantics have been adjusted for greater
+consistency or usefulness in several cases. While the general backwards
+compatibility is maintained, several changes must be noted:
+
+=over 4
+
+=item *
+
+Code references with an empty prototype are no longer treated specially.
+They are passed an argument like the other code references (even if they
+choose to ignore it).
+
+=item *
+
+C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
+returns a true value for each key of the hash (or element of the
+array), instead of passing the whole hash or array as a reference to
+the subroutine.
+
+=item *
+
+Due to the commutativity breakage, code references are no longer
+treated specially when appearing on the left of the C<~~> operator,
+but like any vulgar scalar.
+
+=item *
+
+C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
+hash). No implicit conversion to C<""> is done (as was the case in perl
+5.10.0).
+
+=item *
+
+C<$scalar ~~ @array> now always distributes the smart match across the
+elements of the array. It's true if one element in @array verifies
+C<$scalar ~~ $element>. This is a generalization of the old behaviour
+that tested whether the array contained the scalar.
+
+=back
+
+The full dispatch table for the smart match operator is given in
+L<perlsyn/"Smart matching in detail">.
+
+=head3 Smart match and overloading
+
+According to the rule of dispatch based on the rightmost argument type,
+when an object overloading C<~~> appears on the right side of the
+operator, the overload routine will always be called (with a 3rd argument
+set to a true value, see L<overload>.) However, when the object will
+appear on the left, the overload routine will be called only when the
+rightmost argument is a simple scalar. This way distributivity of smart match
+across arrays is not broken, as well as the other behaviours with complex
+types (coderefs, hashes, regexes). Thus, writers of overloading routines
+for smart match mostly need to worry only with comparing against a scalar,
+and possibly with stringification overloading; the other common cases
+will be automatically handled consistently.
+
+C<~~> will now refuse to work on objects that do not overload it (in order
+to avoid relying on the object's underlying structure). (However, if the
+object overloads the stringification or the numification operators, and
+if overload fallback is active, it will be used instead, as usual.)
+
+=head2 Other incompatible changes
+
+=over 4
+
+=item *
+
+The semantics of C<use feature :5.10*> have changed slightly.
+See L<"Modules and Pragmata"> for more information.
+
+=item *
+
+It is now a run-time error to use the smart match operator C<~~>
+with an object that has no overload defined for it. (This way
+C<~~> will not break encapsulation by matching against the
+object's internal representation as a reference.)
+
+=item *
+
+The version control system used for the development of the perl
+interpreter has been switched from Perforce to git. This is mainly an
+internal issue that only affects people actively working on the perl core;
+but it may have minor external visibility, for example in some of details
+of the output of C<perl -V>. See L<perlrepository> for more information.
+
+=item *
+
+The internal structure of the C<ext/> directory in the perl source has
+been reorganised. In general, a module C<Foo::Bar> whose source was
+stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also,
+some modules have been moved from F<lib/> to F<ext/>. This is purely a
+source tarball change, and should make no difference to the compilation or
+installation of perl, unless you have a very customised build process that
+explicitly relies on this structure, or which hard-codes the C<nonxs_ext>
+F<Configure> parameter. Specifically, this change does not by default
+alter the location of any files in the final installation.
+
+=item *
+
+As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
+C<Test::Harness::Straps> module has been removed.
+See L</"Updated Modules"> for more details.
+
+=item *
+
+As part of the C<ExtUtils::MakeMaker> upgrade, the
+C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
+have been removed from this distribution.
+
+=item *
+
+C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
+
+=item *
+
+This one is actually a change introduced in 5.10.0, but it was missed
+from that release's perldelta, so it is mentioned here instead.
+
+A bugfix related to the handling of the C</m> modifier and C<qr> resulted
+in a change of behaviour between 5.8.x and 5.10.0:
+
+ # matches in 5.8.x, doesn't match in 5.10.0
+ $re = qr/^bar/; "foo\nbar" =~ /$re/m;
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Unicode Character Database 5.1.0
+
+The copy of the Unicode Character Database included in Perl 5.10.1 has
+been updated to 5.1.0 from 5.0.0. See
+L<http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes> for the
+notable changes.
+
+=head2 A proper interface for pluggable Method Resolution Orders
+
+As of Perl 5.10.1 there is a new interface for plugging and using method
+resolution orders other than the default (linear depth first search).
+The C3 method resolution order added in 5.10.0 has been re-implemented as
+a plugin, without changing its Perl-space interface. See L<perlmroapi> for
+more information.
+
+=head2 The C<overloading> pragma
+
+This pragma allows you to lexically disable or enable overloading
+for some or all operations. (Yuval Kogman)
+
+=head2 Parallel tests
+
+The core distribution can now run its regression tests in parallel on
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
+your environment to the number of tests to run in parallel, and run
+C<make test_harness>. On a Bourne-like shell, this can be done as
+
+ TEST_JOBS=3 make test_harness # Run 3 tests in parallel
+
+An environment variable is used, rather than parallel make itself, because
+L<TAP::Harness> needs to be able to schedule individual non-conflicting test
+scripts itself, and there is no standard interface to C<make> utilities to
+interact with their job schedulers.
+
+Note that currently some test scripts may fail when run in parallel (most
+notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
+again sequentially and see if the failures go away.
+
+=head2 DTrace support
+
+Some support for DTrace has been added. See "DTrace support" in F<INSTALL>.
+
+=head2 Support for C<configure_requires> in CPAN module metadata
+
+Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
+in the C<META.yml> metadata file included in most recent CPAN distributions.
+This allows distribution authors to specify configuration prerequisites that
+must be installed before running F<Makefile.PL> or F<Build.PL>.
+
+See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
+on how to specify C<configure_requires> when creating a distribution for CPAN.
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item C<autodie>
+
+This is a new lexically-scoped alternative for the C<Fatal> module.
+The bundled version is 2.06_01. Note that in this release, using a string
+eval when C<autodie> is in effect can cause the autodie behaviour to leak
+into the surrounding scope. See L<autodie/"BUGS"> for more details.
+
+=item C<Compress::Raw::Bzip2>
+
+This has been added to the core (version 2.020).
+
+=item C<parent>
+
+This pragma establishes an ISA relationship with base classes at compile
+time. It provides the key feature of C<base> without the feature creep.
+
+=item C<Parse::CPAN::Meta>
+
+This has been added to the core (version 1.39).
+
+=back
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<attributes>
+
+Upgraded from version 0.08 to 0.09.
+
+=item C<attrs>
+
+Upgraded from version 1.02 to 1.03.
+
+=item C<base>
+
+Upgraded from version 2.13 to 2.14. See L<parent> for a replacement.
+
+=item C<bigint>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<bignum>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<bigrat>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<charnames>
+
+Upgraded from version 1.06 to 1.07.
+
+The Unicode F<NameAliases.txt> database file has been added. This has the
+effect of adding some extra C<\N> character names that formerly wouldn't
+have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">.
+
+=item C<constant>
+
+Upgraded from version 1.13 to 1.17.
+
+=item C<feature>
+
+The meaning of the C<:5.10> and C<:5.10.X> feature bundles has
+changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
+This is predicated on the assumption that new features will not, in
+general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
+have identical effect. This is a change to the behaviour documented for
+5.10.0.
+
+=item C<fields>
+
+Upgraded from version 2.13 to 2.14 (this was just a version bump; there
+were no functional changes).
+
+=item C<lib>
+
+Upgraded from version 0.5565 to 0.62.
+
+=item C<open>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<overload>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<overloading>
+
+See L</"The C<overloading> pragma"> above.
+
+=item C<version>
+
+Upgraded from version 0.74 to 0.77.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Archive::Extract>
+
+Upgraded from version 0.24 to 0.34.
+
+=item C<Archive::Tar>
+
+Upgraded from version 1.38 to 1.52.
+
+=item C<Attribute::Handlers>
+
+Upgraded from version 0.79 to 0.85.
+
+=item C<AutoLoader>
+
+Upgraded from version 5.63 to 5.68.
+
+=item C<AutoSplit>
+
+Upgraded from version 1.05 to 1.06.
+
+=item C<B>
+
+Upgraded from version 1.17 to 1.22.
+
+=item C<B::Debug>
+
+Upgraded from version 1.05 to 1.11.
+
+=item C<B::Deparse>
+
+Upgraded from version 0.83 to 0.89.
+
+=item C<B::Lint>
+
+Upgraded from version 1.09 to 1.11.
+
+=item C<B::Xref>
+
+Upgraded from version 1.01 to 1.02.
+
+=item C<Benchmark>
+
+Upgraded from version 1.10 to 1.11.
+
+=item C<Carp>
+
+Upgraded from version 1.08 to 1.11.
+
+=item C<CGI>
+
+Upgraded from version 3.29 to 3.43.
+(also includes the "default_value for popup_menu()" fix from 3.45).
+
+=item C<Compress::Zlib>
+
+Upgraded from version 2.008 to 2.020.
+
+=item C<CPAN>
+
+Upgraded from version 1.9205 to 1.9402. C<CPAN::FTP> has a local fix to
+stop it being too verbose on download failure.
+
+=item C<CPANPLUS>
+
+Upgraded from version 0.84 to 0.88.
+
+=item C<CPANPLUS::Dist::Build>
+
+Upgraded from version 0.06_02 to 0.36.
+
+=item C<Cwd>
+
+Upgraded from version 3.25_01 to 3.30.
+
+=item C<Data::Dumper>
+
+Upgraded from version 2.121_14 to 2.124.
+
+=item C<DB>
+
+Upgraded from version 1.01 to 1.02.
+
+=item C<DB_File>
+
+Upgraded from version 1.816_1 to 1.820.
+
+=item C<Devel::PPPort>
+
+Upgraded from version 3.13 to 3.19.
+
+=item C<Digest::MD5>
+
+Upgraded from version 2.36_01 to 2.39.
+
+=item C<Digest::SHA>
+
+Upgraded from version 5.45 to 5.47.
+
+=item C<DirHandle>
+
+Upgraded from version 1.01 to 1.03.
+
+=item C<Dumpvalue>
+
+Upgraded from version 1.12 to 1.13.
+
+=item C<DynaLoader>
+
+Upgraded from version 1.08 to 1.10.
+
+=item C<Encode>
+
+Upgraded from version 2.23 to 2.35.
+
+=item C<Errno>
+
+Upgraded from version 1.10 to 1.11.
+
+=item C<Exporter>
+
+Upgraded from version 5.62 to 5.63.
+
+=item C<ExtUtils::CBuilder>
+
+Upgraded from version 0.21 to 0.2602.
+
+=item C<ExtUtils::Command>
+
+Upgraded from version 1.13 to 1.16.
+
+=item C<ExtUtils::Constant>
+
+Upgraded from 0.20 to 0.22. (Note that neither of these versions are
+available on CPAN.)
+
+=item C<ExtUtils::Embed>
+
+Upgraded from version 1.27 to 1.28.
+
+=item C<ExtUtils::Install>
+
+Upgraded from version 1.44 to 1.54.
+
+=item C<ExtUtils::MakeMaker>
+
+Upgraded from version 6.42 to 6.55_02.
+
+Note that C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish>
+have been removed from this distribution.
+
+=item C<ExtUtils::Manifest>
+
+Upgraded from version 1.51_01 to 1.56.
+
+=item C<ExtUtils::ParseXS>
+
+Upgraded from version 2.18_02 to 2.2002.
+
+=item C<Fatal>
+
+Upgraded from version 1.05 to 2.06_01. See also the new pragma C<autodie>.
+
+=item C<File::Basename>
+
+Upgraded from version 2.76 to 2.77.
+
+=item C<File::Compare>
+
+Upgraded from version 1.1005 to 1.1006.
+
+=item C<File::Copy>
+
+Upgraded from version 2.11 to 2.14.
+
+=item C<File::Fetch>
+
+Upgraded from version 0.14 to 0.20.
+
+=item C<File::Find>
+
+Upgraded from version 1.12 to 1.14.
+
+=item C<File::Path>
+
+Upgraded from version 2.04 to 2.07_03.
+
+=item C<File::Spec>
+
+Upgraded from version 3.2501 to 3.30.
+
+=item C<File::stat>
+
+Upgraded from version 1.00 to 1.01.
+
+=item C<File::Temp>
+
+Upgraded from version 0.18 to 0.22.
+
+=item C<FileCache>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<FileHandle>
+
+Upgraded from version 2.01 to 2.02.
+
+=item C<Filter::Simple>
+
+Upgraded from version 0.82 to 0.84.
+
+=item C<Filter::Util::Call>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<FindBin>
+
+Upgraded from version 1.49 to 1.50.
+
+=item C<GDBM_File>
+
+Upgraded from version 1.08 to 1.09.
+
+=item C<Getopt::Long>
+
+Upgraded from version 2.37 to 2.38.
+
+=item C<Hash::Util::FieldHash>
+
+Upgraded from version 1.03 to 1.04. This fixes a memory leak.
+
+=item C<I18N::Collate>
+
+Upgraded from version 1.00 to 1.01.
+
+=item C<IO>
+
+Upgraded from version 1.23_01 to 1.25.
+
+This makes non-blocking mode work on Windows in C<IO::Socket::INET>
+[CPAN #43573].
+
+=item C<IO::Compress::*>
+
+Upgraded from version 2.008 to 2.020.
+
+=item C<IO::Dir>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<IO::Handle>
+
+Upgraded from version 1.27 to 1.28.
+
+=item C<IO::Socket>
+
+Upgraded from version 1.30_01 to 1.31.
+
+=item C<IO::Zlib>
+
+Upgraded from version 1.07 to 1.09.
+
+=item C<IPC::Cmd>
+
+Upgraded from version 0.40_1 to 0.46.
+
+=item C<IPC::Open3>
+
+Upgraded from version 1.02 to 1.04.
+
+=item C<IPC::SysV>
+
+Upgraded from version 1.05 to 2.01.
+
+=item C<lib>
+
+Upgraded from version 0.5565 to 0.62.
+
+=item C<List::Util>
+
+Upgraded from version 1.19 to 1.21.
+
+=item C<Locale::MakeText>
+
+Upgraded from version 1.12 to 1.13.
+
+=item C<Log::Message>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<Math::BigFloat>
+
+Upgraded from version 1.59 to 1.60.
+
+=item C<Math::BigInt>
+
+Upgraded from version 1.88 to 1.89.
+
+=item C<Math::BigInt::FastCalc>
+
+Upgraded from version 0.16 to 0.19.
+
+=item C<Math::BigRat>
+
+Upgraded from version 0.21 to 0.22.
+
+=item C<Math::Complex>
+
+Upgraded from version 1.37 to 1.56.
+
+=item C<Math::Trig>
+
+Upgraded from version 1.04 to 1.20.
+
+=item C<Memoize>
+
+Upgraded from version 1.01_02 to 1.01_03 (just a minor documentation
+change).
+
+=item C<Module::Build>
+
+Upgraded from version 0.2808_01 to 0.34_02.
+
+=item C<Module::CoreList>
+
+Upgraded from version 2.13 to 2.18. This release no longer contains the
+C<%Module::CoreList::patchlevel> hash.
+
+=item C<Module::Load>
+
+Upgraded from version 0.12 to 0.16.
+
+=item C<Module::Load::Conditional>
+
+Upgraded from version 0.22 to 0.30.
+
+=item C<Module::Loaded>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<Module::Pluggable>
+
+Upgraded from version 3.6 to 3.9.
+
+=item C<NDBM_File>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<Net::Ping>
+
+Upgraded from version 2.33 to 2.36.
+
+=item C<NEXT>
+
+Upgraded from version 0.60_01 to 0.64.
+
+=item C<Object::Accessor>
+
+Upgraded from version 0.32 to 0.34.
+
+=item C<OS2::REXX>
+
+Upgraded from version 1.03 to 1.04.
+
+=item C<Package::Constants>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<PerlIO>
+
+Upgraded from version 1.04 to 1.06.
+
+=item C<PerlIO::via>
+
+Upgraded from version 0.04 to 0.07.
+
+=item C<Pod::Man>
+
+Upgraded from version 2.16 to 2.22.
+
+=item C<Pod::Parser>
+
+Upgraded from version 1.35 to 1.37.
+
+=item C<Pod::Simple>
+
+Upgraded from version 3.05 to 3.07.
+
+=item C<Pod::Text>
+
+Upgraded from version 3.08 to 3.13.
+
+=item C<POSIX>
+
+Upgraded from version 1.13 to 1.17.
+
+=item C<Safe>
+
+Upgraded from 2.12 to 2.18.
+
+=item C<Scalar::Util>
+
+Upgraded from version 1.19 to 1.21.
+
+=item C<SelectSaver>
+
+Upgraded from 1.01 to 1.02.
+
+=item C<SelfLoader>
+
+Upgraded from 1.11 to 1.17.
+
+=item C<Socket>
+
+Upgraded from 1.80 to 1.82.
+
+=item C<Storable>
+
+Upgraded from 2.18 to 2.20.
+
+=item C<Switch>
+
+Upgraded from version 2.13 to 2.14. Please see L</Deprecations>.
+
+=item C<Symbol>
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<Sys::Syslog>
+
+Upgraded from version 0.22 to 0.27.
+
+=item C<Term::ANSIColor>
+
+Upgraded from version 1.12 to 2.00.
+
+=item C<Term::ReadLine>
+
+Upgraded from version 1.03 to 1.04.
+
+=item C<Term::UI>
+
+Upgraded from version 0.18 to 0.20.
+
+=item C<Test::Harness>
+
+Upgraded from version 2.64 to 3.17.
+
+Note that one side-effect of the 2.x to 3.x upgrade is that the
+experimental C<Test::Harness::Straps> module (and its supporting
+C<Assert>, C<Iterator>, C<Point> and C<Results> modules) have been
+removed. If you still need this, then they are available in the
+(unmaintained) C<Test-Harness-Straps> distribution on CPAN.
+
+=item C<Test::Simple>
+
+Upgraded from version 0.72 to 0.92.
+
+=item C<Text::ParseWords>
+
+Upgraded from version 3.26 to 3.27.
+
+=item C<Text::Tabs>
+
+Upgraded from version 2007.1117 to 2009.0305.
+
+=item C<Text::Wrap>
+
+Upgraded from version 2006.1117 to 2009.0305.
+
+=item C<Thread::Queue>
+
+Upgraded from version 2.00 to 2.11.
+
+=item C<Thread::Semaphore>
+
+Upgraded from version 2.01 to 2.09.
+
+=item C<threads>
+
+Upgraded from version 1.67 to 1.72.
+
+=item C<threads::shared>
+
+Upgraded from version 1.14 to 1.29.
+
+=item C<Tie::RefHash>
+
+Upgraded from version 1.37 to 1.38.
+
+=item C<Tie::StdHandle>
+
+This has documentation changes, and has been assigned a version for the
+first time: version 4.2.
+
+=item C<Time::HiRes>
+
+Upgraded from version 1.9711 to 1.9719.
+
+=item C<Time::Local>
+
+Upgraded from version 1.18 to 1.1901.
+
+=item C<Time::Piece>
+
+Upgraded from version 1.12 to 1.15.
+
+=item C<Unicode::Normalize>
+
+Upgraded from version 1.02 to 1.03.
+
+=item C<Unicode::UCD>
+
+Upgraded from version 0.25 to 0.27.
+
+C<charinfo()> now works on Unified CJK code points added to later versions
+of Unicode.
+
+C<casefold()> has new fields returned to provide both a simpler interface
+and previously missing information. The old fields are retained for
+backwards compatibility. Information about Turkic-specific code points is
+now returned.
+
+The documentation has been corrected and expanded.
+
+=item C<UNIVERSAL>
+
+Upgraded from version 1.04 to 1.05.
+
+=item C<Win32>
+
+Upgraded from version 0.34 to 0.39.
+
+=item C<Win32API::File>
+
+Upgraded from version 0.1001_01 to 0.1101.
+
+=item C<XSLoader>
+
+Upgraded from version 0.08 to 0.10.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item F<h2ph>
+
+Now looks in C<include-fixed> too, which is a recent addition to gcc's
+search path.
+
+=item F<h2xs>
+
+No longer incorrectly treats enum values like macros (Daniel Burr).
+
+Now handles C++ style constants (C<//>) properly in enums. (A patch from
+Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
+
+=item F<perl5db.pl>
+
+C<LVALUE> subroutines now work under the debugger.
+
+The debugger now correctly handles proxy constant subroutines, and
+subroutine stubs.
+
+=item F<perlthanks>
+
+Perl 5.10.1 adds a new utility F<perlthanks>, which is a variant of
+F<perlbug>, but for sending non-bug-reports to the authors and maintainers
+of Perl. Getting nothing but bug reports can become a bit demoralising:
+we'll see if this changes things.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item L<perlhaiku>
+
+This contains instructions on how to build perl for the Haiku platform.
+
+=item L<perlmroapi>
+
+This describes the new interface for pluggable Method Resolution Orders.
+
+=item L<perlperf>
+
+This document, by Richard Foley, provides an introduction to the use of
+performance and optimization techniques which can be used with particular
+reference to perl programs.
+
+=item L<perlrepository>
+
+This describes how to access the perl source using the I<git> version
+control system.
+
+=item L<perlthanks>
+
+This describes the new F<perlthanks> utility.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+The various large C<Changes*> files (which listed every change made to perl
+over the last 18 years) have been removed, and replaced by a small file,
+also called C<Changes>, which just explains how that same information may
+be extracted from the git version control system.
+
+The file F<Porting/patching.pod> has been deleted, as it mainly described
+interacting with the old Perforce-based repository, which is now obsolete.
+Information still relevant has been moved to L<perlrepository>.
+
+L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
+generated at build time, rather than being shipped as part of the release.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+A new internal cache means that C<isa()> will often be faster.
+
+=item *
+
+Under C<use locale>, the locale-relevant information is now cached on
+read-only values, such as the list returned by C<keys %hash>. This makes
+operations such as C<sort keys %hash> in the scope of C<use locale> much
+faster.
+
+=item *
+
+Empty C<DESTROY> methods are no longer called.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 F<ext/> reorganisation
+
+The layout of directories in F<ext> has been revised. Specifically, all
+extensions are now flat, and at the top level, with C</> in pathnames
+replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>,
+etc. The names of the extensions as specified to F<Configure>, and as
+reported by C<%Config::Config> under the keys C<dynamic_ext>,
+C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and
+still use C</>. Hence this change will not have any affect once perl is
+installed. However, C<Attribute::Handlers>, C<Safe> and C<mro> have now
+become extensions in their own right, so if you run F<Configure> with
+options to specify an exact list of extensions to build, you will need to
+change it to account for this.
+
+For 5.10.2, it is planned that many dual-life modules will have been moved
+from F<lib> to F<ext>; again this will have no effect on an installed
+perl, but will matter if you invoke F<Configure> with a pre-canned list of
+extensions to build.
+
+=head2 Configuration improvements
+
+If C<vendorlib> and C<vendorarch> are the same, then they are only added to
+C<@INC> once.
+
+C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
+perl is built with C<-Dusedevel>.
+
+F<Configure> will enable use of C<-fstack-protector>, to provide protection
+against stack-smashing attacks, if the compiler supports it.
+
+F<Configure> will now determine the correct prototypes for re-entrant
+functions, and for C<gconvert>, if you are using a C++ compiler rather
+than a C compiler.
+
+On Unix, if you build from a tree containing a git repository, the
+configuration process will note the commit hash you have checked out, for
+display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
+are automatically added to the list of local patches displayed by
+C<perl -V>.
+
+=head2 Compilation improvements
+
+As part of the flattening of F<ext>, all extensions on all platforms are
+built by F<make_ext.pl>. This replaces the Unix-specific
+F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
+F<win32/buildext.pl>.
+
+=head2 Platform Specific Changes
+
+=over 4
+
+=item AIX
+
+Removed F<libbsd> for AIX 5L and 6.1. Only flock() was used from F<libbsd>.
+
+Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an
+optional package with the AIX Toolbox. Unfortunately the 64 bit version
+is broken.
+
+Hints changes mean that AIX 4.2 should work again.
+
+=item Cygwin
+
+On Cygwin we now strip the last number from the DLL. This has been the
+behaviour in the cygwin.com build for years. The hints files have been
+updated.
+
+=item FreeBSD
+
+The hints files now identify the correct threading libraries on FreeBSD 7
+and later.
+
+=item Irix
+
+We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
+C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
+
+=item Haiku
+
+Patches from the Haiku maintainers have been merged in. Perl should now
+build on Haiku.
+
+=item MirOS BSD
+
+Perl should now build on MirOS BSD.
+
+=item NetBSD
+
+Hints now supports versions 5.*.
+
+=item Stratus VOS
+
+Various changes from Stratus have been merged in.
+
+=item Symbian
+
+There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
+
+=item Win32
+
+Improved message window handling means that C<alarm> and C<kill> messages
+will no longer be dropped under race conditions.
+
+=item VMS
+
+Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
+if C<$/> was set to a numeric reference (to indicate record-style reads).
+This is now fixed.
+
+VMS now supports C<getgrgid>.
+
+Many improvements and cleanups have been made to the VMS file name handling
+and conversion code.
+
+Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
+status in a VMS condition value for better interaction with GNV's bash
+shell and other utilities that depend on POSIX exit values. See
+L<perlvms/"$?"> for details.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+5.10.0 inadvertently disabled an optimisation, which caused a measurable
+performance drop in list assignment, such as is often used to assign
+function parameters from C<@_>. The optimisation has been re-instated, and
+the performance regression fixed.
+
+=item *
+
+Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
+
+=item *
+
+Some potential coredumps in PerlIO fixed [RT #57322,54828].
+
+=item *
+
+The debugger now works with lvalue subroutines.
+
+=item *
+
+The debugger's C<m> command was broken on modules that defined constants
+[RT #61222].
+
+=item *
+
+C<crypt()> and string complement could return tainted values for untainted
+arguments [RT #59998].
+
+=item *
+
+The C<-i.suffix> command-line switch now recreates the file using
+restricted permissions, before changing its mode to match the original
+file. This eliminates a potential race condition [RT #60904].
+
+=item *
+
+On some Unix systems, the value in C<$?> would not have the top bit set
+(C<$? & 128>) even if the child core dumped.
+
+=item *
+
+Under some circumstances, $^R could incorrectly become undefined
+[RT #57042].
+
+=item *
+
+(XS) In various hash functions, passing a pre-computed hash to when the
+key is UTF-8 might result in an incorrect lookup.
+
+=item *
+
+(XS) Including F<XSUB.h> before F<perl.h> gave a compile-time error
+[RT #57176].
+
+=item *
+
+C<< $object->isa('Foo') >> would report false if the package C<Foo> didn't
+exist, even if the object's C<@ISA> contained C<Foo>.
+
+=item *
+
+Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
+C<@ISA>, have been found and fixed.
+
+=item *
+
+Bitwise operations on references could crash the interpreter, e.g.
+C<$x=\$y; $x |= "foo"> [RT #54956].
+
+=item *
+
+Patterns including alternation might be sensitive to the internal UTF-8
+representation, e.g.
+
+ my $byte = chr(192);
+ my $utf8 = chr(192); utf8::upgrade($utf8);
+ $utf8 =~ /$byte|X}/i; # failed in 5.10.0
+
+=item *
+
+Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
+effect), double-quoted literal strings could be corrupted where a C<\xNN>,
+C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
+greater than 255 [RT #59908].
+
+=item *
+
+C<B::Deparse> failed to correctly deparse various constructs:
+C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
+C<sub foo(_)> [RT #62484].
+
+=item *
+
+Using C<setpgrp()> with no arguments could corrupt the perl stack.
+
+=item *
+
+The block form of C<eval> is now specifically trappable by C<Safe> and
+C<ops>. Previously it was erroneously treated like string C<eval>.
+
+=item *
+
+In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
+match operator (C<~~>) [RT #63854].
+
+=item *
+
+In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
+C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
+
+ ("ab" x 32768) =~ /^(ab)*$/
+
+=item *
+
+C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
+
+=item *
+
+Using C<next> or C<last> to exit a C<given> block no longer produces a
+spurious warning like the following:
+
+ Exiting given via last at foo.pl line 123
+
+=item *
+
+On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than
+C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
+
+=item *
+
+Assigning a format to a glob could corrupt the format; e.g.:
+
+ *bar=*foo{FORMAT}; # foo format now bad
+
+=item *
+
+Attempting to coerce a typeglob to a string or number could cause an
+assertion failure. The correct error message is now generated,
+C<Can't coerce GLOB to I<$type>>.
+
+=item *
+
+Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
+has been fixed [RT #49003].
+
+=item *
+
+C<length> on a tied scalar that returned a Unicode value would not be
+correct the first time. This has been fixed.
+
+=item *
+
+Using an array C<tie> inside in array C<tie> could SEGV. This has been
+fixed. [RT #51636]
+
+=item *
+
+A race condition inside C<PerlIOStdio_close()> has been identified and
+fixed. This used to cause various threading issues, including SEGVs.
+
+=item *
+
+In C<unpack>, the use of C<()> groups in scalar context was internally
+placing a list on the interpreter's stack, which manifested in various
+ways, including SEGVs. This is now fixed [RT #50256].
+
+=item *
+
+Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
+These have all been fixed.
+
+=item *
+
+A 5.10.0 optimisation to clear the temporary stack within the implicit
+loop of C<s///ge> has been reverted, as it turned out to be the cause of
+obscure bugs in seemingly unrelated parts of the interpreter [commit
+ef0d4e17921ee3de].
+
+=item *
+
+The line numbers for warnings inside C<elsif> are now correct.
+
+=item *
+
+The C<..> operator now works correctly with ranges whose ends are at or
+close to the values of the smallest and largest integers.
+
+=item *
+
+C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
+This has been fixed [RT #54828].
+
+=item *
+
+An off-by-one error meant that C<index $str, ...> was effectively being
+executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
+
+=item *
+
+Various leaks associated with named captures in regexes have been fixed
+[RT #57024].
+
+=item *
+
+A weak reference to a hash would leak. This was affecting C<DBI>
+[RT #56908].
+
+=item *
+
+Using (?|) in a regex could cause a segfault [RT #59734].
+
+=item *
+
+Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
+
+=item *
+
+Calling C<sv_chop()> or otherwise upgrading an SV could result in an
+unaligned 64-bit access on the SPARC architecture [RT #60574].
+
+=item *
+
+In the 5.10.0 release, C<inc_version_list> would incorrectly list
+C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
+[RT #67628].
+
+=item *
+
+In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
+[RT #52552].
+
+=item *
+
+In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
+C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
+[RT #62666].
+
+=item *
+
+In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
+missed (method cache issue) [RT #60220,60232].
+
+=item *
+
+In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
+cause a memory leak [RT #63110].
+
+=item *
+
+C<-C> on the shebang (C<#!>) line is once more permitted if it is also
+specified on the command line. C<-C> on the shebang line used to be a
+silent no-op I<if> it was not also on the command line, so perl 5.10.0
+disallowed it, which broke some scripts. Now perl checks whether it is
+also on the command line and only dies if it is not [RT #67880].
+
+=item *
+
+In 5.10.0, certain types of re-entrant regular expression could crash,
+or cause the following assertion failure [RT #60508]:
+
+ Assertion rx->sublen >= (s - rx->subbeg) + i failed
+
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item C<panic: sv_chop %s>
+
+This new fatal error occurs when the C routine C<Perl_sv_chop()> was
+passed a position that is not within the scalar's string buffer. This
+could be caused by buggy XS code, and at this point recovery is not
+possible.
+
+=item C<Can't locate package %s for the parents of %s>
+
+This warning has been removed. In general, it only got produced in
+conjunction with other warnings, and removing it allowed an ISA lookup
+optimisation to be added.
+
+=item C<v-string in use/require is non-portable>
+
+This warning has been removed.
+
+=item C<Deep recursion on subroutine "%s">
+
+It is now possible to change the depth threshold for this warning from the
+default of 100, by recompiling the F<perl> binary, setting the C
+pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+The J.R.R. Tolkien quotes at the head of C source file have been checked and
+proper citations added, thanks to a patch from Tom Christiansen.
+
+=item *
+
+C<vcroak()> now accepts a null first argument. In addition, a full audit
+was made of the "not NULL" compiler annotations, and those for several
+other internal functions were corrected.
+
+=item *
+
+New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
+have been added to formalise the temporary saving of the C<errno>
+variable.
+
+=item *
+
+The function C<Perl_sv_insert_flags> has been added to augment
+C<Perl_sv_insert>.
+
+=item *
+
+The function C<Perl_newSV_type(type)> has been added, equivalent to
+C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
+
+=item *
+
+The function C<Perl_newSVpvn_flags()> has been added, equivalent to
+C<Perl_newSVpvn()> and then performing the action relevant to the flag.
+
+Two flag bits are currently supported.
+
+=over 4
+
+=item C<SVf_UTF8>
+
+This will call C<SvUTF8_on()> for you. (Note that this does not convert an
+sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
+is available for this.
+
+=item C<SVs_TEMP>
+
+Call C<sv_2mortal()> on the new SV.
+
+=back
+
+There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
+
+=item *
+
+The function C<Perl_croak_xs_usage> has been added as a wrapper to
+C<Perl_croak>.
+
+=item *
+
+The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now
+exported.
+
+=item *
+
+C<PL_na> has been exterminated from the core code, replaced by local STRLEN
+temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
+which is a pointer deference into the interpreter structure under ithreads,
+and a global variable otherwise.
+
+=item *
+
+C<Perl_mg_free()> used to leave freed memory accessible via SvMAGIC() on
+the scalar. It now updates the linked list to remove each piece of magic
+as it is freed.
+
+=item *
+
+Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
+eliminates a lot of hackish workarounds to cope with it not being reference
+counted.
+
+=item *
+
+C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
+This has been fixed.
+
+=item *
+
+The I<public> IV and NV flags are now not set if the string value has
+trailing "garbage". This behaviour is consistent with not setting the
+public IV or NV flags if the value is out of range for the type.
+
+=item *
+
+SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
+The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
+that was enabled when the F<perl> binary was compiled.
+
+=item *
+
+Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
+replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
+is clearer to those unfamiliar with the core code.
+
+=item *
+
+A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
+not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
+C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
+casting away C<const>. This allows proper compile-time auditing of
+C<const> correctness in the core, and helped picked up some errors (now
+fixed).
+
+=item *
+
+Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
+stack and mortalizing them.
+
+=item *
+
+Use of the private structure C<mro_meta> has changed slightly. Nothing
+outside the core should be accessing this directly anyway.
+
+=item *
+
+A new tool, C<Porting/expand-macro.pl> has been added, that allows you
+to view how a C preprocessor macro would be expanded when compiled.
+This is handy when trying to decode the macro hell that is the perl
+guts.
+
+=back
+
+=head1 New Tests
+
+Many modules updated from CPAN incorporate new tests.
+
+Several tests that have the potential to hang forever if they fail now
+incorporate a "watchdog" functionality that will kill them after a timeout,
+which helps ensure that C<make test> and C<make test_harness> run to
+completion automatically. (Jerry Hedden).
+
+Some core-specific tests have been added:
+
+=over 4
+
+=item t/comp/retainedlines.t
+
+Check that the debugger can retain source lines from C<eval>.
+
+=item t/io/perlio_fail.t
+
+Check that bad layers fail.
+
+=item t/io/perlio_leaks.t
+
+Check that PerlIO layers are not leaking.
+
+=item t/io/perlio_open.t
+
+Check that certain special forms of open work.
+
+=item t/io/perlio.t
+
+General PerlIO tests.
+
+=item t/io/pvbm.t
+
+Check that there is no unexpected interaction between the internal types
+C<PVBM> and C<PVGV>.
+
+=item t/mro/package_aliases.t
+
+Check that mro works properly in the presence of aliased packages.
+
+=item t/op/dbm.t
+
+Tests for C<dbmopen> and C<dbmclose>.
+
+=item t/op/index_thr.t
+
+Tests for the interaction of C<index> and threads.
+
+=item t/op/pat_thr.t
+
+Tests for the interaction of esoteric patterns and threads.
+
+=item t/op/qr_gc.t
+
+Test that C<qr> doesn't leak.
+
+=item t/op/reg_email_thr.t
+
+Tests for the interaction of regex recursion and threads.
+
+=item t/op/regexp_qr_embed_thr.t
+
+Tests for the interaction of patterns with embedded C<qr//> and threads.
+
+=item t/op/regexp_unicode_prop.t
+
+Tests for Unicode properties in regular expressions.
+
+=item t/op/regexp_unicode_prop_thr.t
+
+Tests for the interaction of Unicode properties and threads.
+
+=item t/op/reg_nc_tie.t
+
+Test the tied methods of C<Tie::Hash::NamedCapture>.
+
+=item t/op/reg_posixcc.t
+
+Check that POSIX character classes behave consistently.
+
+=item t/op/re.t
+
+Check that exportable C<re> functions in F<universal.c> work.
+
+=item t/op/setpgrpstack.t
+
+Check that C<setpgrp> works.
+
+=item t/op/substr_thr.t
+
+Tests for the interaction of C<substr> and threads.
+
+=item t/op/upgrade.t
+
+Check that upgrading and assigning scalars works.
+
+=item t/uni/lex_utf8.t
+
+Check that Unicode in the lexer works.
+
+=item t/uni/tie.t
+
+Check that Unicode and C<tie> work.
+
+=back
+
+=head1 Known Problems
+
+This is a list of some significant unfixed bugs, which are regressions
+from either 5.10.0 or 5.8.x.
+
+=over 4
+
+=item *
+
+C<List::Util::first> misbehaves in the presence of a lexical C<$_>
+(typically introduced by C<my $_> or implicitly by C<given>). The variable
+which gets set for each iteration is the package variable C<$_>, not the
+lexical C<$_> [RT #67694].
+
+A similar issue may occur in other modules that provide functions which
+take a block as their first argument, like
+
+ foo { ... $_ ...} list
+
+=item *
+
+The C<charnames> pragma may generate a run-time error when a regex is
+interpolated [RT #56444]:
+
+ use charnames ':full';
+ my $r1 = qr/\N{THAI CHARACTER SARA I}/;
+ "foo" =~ $r1; # okay
+ "foo" =~ /$r1+/; # runtime error
+
+A workaround is to generate the character outside of the regex:
+
+ my $a = "\N{THAI CHARACTER SARA I}";
+ my $r1 = qr/$a/;
+
+=item *
+
+Some regexes may run much more slowly when run in a child thread compared
+with the thread the pattern was compiled into [RT #55600].
+
+
+=back
+
+=head1 Deprecations
+
+The following items are now deprecated.
+
+=over 4
+
+=item *
+
+C<Switch> is buggy and should be avoided. From perl 5.11.0 onwards, it is
+intended that any use of the core version of this module will emit a
+warning, and that the module will eventually be removed from the core
+(probably in perl 5.14.0). See L<perlsyn/"Switch statements"> for its
+replacement.
+
+=item *
+
+C<suidperl> will be removed in 5.12.0. This provides a mechanism to
+emulate setuid permission bits on systems that don't support it properly.
+
+=back
+
+=head1 Acknowledgements
+
+Some of the work in this release was funded by a TPF grant.
+
+Nicholas Clark officially retired from maintenance pumpking duty at the
+end of 2008; however in reality he has put much effort in since then to
+help get 5.10.1 into a fit state to be released, including writing a
+considerable chunk of this perldelta.
+
+Steffen Mueller and David Golden in particular helped getting CPAN modules
+polished and synchronised with their in-core equivalents.
+
+Craig Berry was tireless in getting maint to run under VMS, no matter how
+many times we broke it for him.
+
+The other core committers contributed most of the changes, and applied most
+of the patches sent in by the hundreds of contributors listed in F<AUTHORS>.
+
+(Sorry to all the people I haven't mentioned by name).
+
+Finally, thanks to Larry Wall, without whom none of this would be
+necessary.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5110delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5110delta.pod
new file mode 100644
index 00000000000..1b722ed7e8e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5110delta.pod
@@ -0,0 +1,1624 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5110delta - what is new for perl v5.11.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.10.0 release and
+the 5.11.0 development release.
+
+=head1 Incompatible Changes
+
+=head2 Unicode interpretation of \w, \d, \s, and the POSIX character classes redefined.
+
+Previous versions of Perl tried to map POSIX style character class definitions onto
+Unicode property names so that patterns would "dwim" when matches were made against latin-1 or
+unicode strings. This proved to be a mistake, breaking character class negation, causing
+forward compatibility problems (as Unicode keeps updating their property definitions and adding
+new characters), and other problems.
+
+Therefore we have now defined a new set of artificial "unicode" property names which will be
+used to do unicode matching of patterns using POSIX style character classes and perl short-form
+escape character classes like \w and \d.
+
+The key change here is that \d will no longer match every digit in the unicode standard
+(there are thousands) nor will \w match every word character in the standard, instead they
+will match precisely their POSIX or Perl definition.
+
+Those needing to match based on Unicode properties can continue to do so by using the \p{} syntax
+to match whichever property they like, including the new artificial definitions.
+
+B<NOTE:> This is a backwards incompatible no-warning change in behaviour. If you are upgrading
+and you process large volumes of text look for POSIX and Perl style character classes and
+change them to the relevent property name (by removing the word 'Posix' from the current name).
+
+The following table maps the POSIX character class names, the escapes and the old and new
+Unicode property mappings:
+
+ POSIX Esc Class New-Property ! Old-Property
+ ----------------------------------------------+-------------
+ alnum [0-9A-Za-z] IsPosixAlnum ! IsAlnum
+ alpha [A-Za-z] IsPosixAlpha ! IsAlpha
+ ascii [\000-\177] IsASCII = IsASCII
+ blank [\011 ] IsPosixBlank !
+ cntrl [\0-\37\177] IsPosixCntrl ! IsCntrl
+ digit \d [0-9] IsPosixDigit ! IsDigit
+ graph [!-~] IsPosixGraph ! IsGraph
+ lower [a-z] IsPosixLower ! IsLower
+ print [ -~] IsPosixPrint ! IsPrint
+ punct [!-/:-@[-`{-~] IsPosixPunct ! IsPunct
+ space [\11-\15 ] IsPosixSpace ! IsSpace
+ \s [\11\12\14\15 ] IsPerlSpace ! IsSpacePerl
+ upper [A-Z] IsPosixUpper ! IsUpper
+ word \w [0-9A-Z_a-z] IsPerlWord ! IsWord
+ xdigit [0-9A-Fa-f] IsXDigit = IsXDigit
+
+If you wish to build perl with the old mapping you may do so by setting
+
+ #define PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS 1
+
+in regcomp.h, and then setting
+
+ PERL_TEST_LEGACY_POSIX_CC
+
+to true your enviornment when testing.
+
+
+=head2 @INC reorganization
+
+In @INC, ARCHLIB and PRIVLIB now occur after after the current version's
+site_perl and vendor_perl.
+
+=head2 Switch statement changes
+
+The handling of complex expressions by the C<given>/C<when> switch
+statement has been enhanced. These enhancements are also available in
+5.10.1 and subsequent 5.10 releases. There are two new cases where C<when> now
+interprets its argument as a boolean, instead of an expression to be used
+in a smart match:
+
+=over 4
+
+=item flip-flop operators
+
+The C<..> and C<...> flip-flop operators are now evaluated in boolean
+context, following their usual semantics; see L<perlop/"Range Operators">.
+
+Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
+whether a given value is an integer between 1 and 10; you should use
+C<when ([1..10])> instead (note the array reference).
+
+However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
+context ensures it can now be useful in a C<when()>, notably for
+implementing bistable conditions, like in:
+
+ when (/^=begin/ .. /^=end/) {
+ # do something
+ }
+
+=item defined-or operator
+
+A compound expression involving the defined-or operator, as in
+C<when (expr1 // expr2)>, will be treated as boolean if the first
+expression is boolean. (This just extends the existing rule that applies
+to the regular or operator, as in C<when (expr1 || expr2)>.)
+
+=back
+
+The next section details more changes brought to the semantics to
+the smart match operator, that naturally also modify the behaviour
+of the switch statements where smart matching is implicitly used.
+These changers were also made for the 5.10.1 release, and will remain in
+subsequent 5.10 releases.
+
+=head2 Smart match changes
+
+=head3 Changes to type-based dispatch
+
+The smart match operator C<~~> is no longer commutative. The behaviour of
+a smart match now depends primarily on the type of its right hand
+argument. Moreover, its semantics have been adjusted for greater
+consistency or usefulness in several cases. While the general backwards
+compatibility is maintained, several changes must be noted:
+
+=over 4
+
+=item *
+
+Code references with an empty prototype are no longer treated specially.
+They are passed an argument like the other code references (even if they
+choose to ignore it).
+
+=item *
+
+C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
+returns a true value for each key of the hash (or element of the
+array), instead of passing the whole hash or array as a reference to
+the subroutine.
+
+=item *
+
+Due to the commutativity breakage, code references are no longer
+treated specially when appearing on the left of the C<~~> operator,
+but like any vulgar scalar.
+
+=item *
+
+C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
+hash). No implicit conversion to C<""> is done (as was the case in perl
+5.10.0).
+
+=item *
+
+C<$scalar ~~ @array> now always distributes the smart match across the
+elements of the array. It's true if one element in @array verifies
+C<$scalar ~~ $element>. This is a generalization of the old behaviour
+that tested whether the array contained the scalar.
+
+=back
+
+The full dispatch table for the smart match operator is given in
+L<perlsyn/"Smart matching in detail">.
+
+=head3 Smart match and overloading
+
+According to the rule of dispatch based on the rightmost argument type,
+when an object overloading C<~~> appears on the right side of the
+operator, the overload routine will always be called (with a 3rd argument
+set to a true value, see L<overload>.) However, when the object will
+appear on the left, the overload routine will be called only when the
+rightmost argument is a simple scalar. This way distributivity of smart match
+across arrays is not broken, as well as the other behaviours with complex
+types (coderefs, hashes, regexes). Thus, writers of overloading routines
+for smart match mostly need to worry only with comparing against a scalar,
+and possibly with stringification overloading; the other common cases
+will be automatically handled consistently.
+
+C<~~> will now refuse to work on objects that do not overload it (in order
+to avoid relying on the object's underlying structure). (However, if the
+object overloads the stringification or the numification operators, and
+if overload fallback is active, it will be used instead, as usual.)
+
+=head2 Labels can't be keywords
+
+Labels used as targets for the C<goto>, C<last>, C<next> or C<redo>
+statements cannot be keywords anymore. This restriction will prevent
+potential confusion between the C<goto LABEL> and C<goto EXPR> syntaxes:
+for example, a statement like C<goto print> would jump to a label whose
+name would be the return value of C<print()>, (usually 1), instead of a
+label named C<print>. Moreover, the other control flow statements
+would just ignore any keyword passed to them as a label name. Since
+such labels cannot be defined anymore, this kind of error will be
+avoided.
+
+=head2 Other incompatible changes
+
+=over 4
+
+=item *
+
+The semantics of C<use feature :5.10*> have changed slightly.
+See L<"Modules and Pragmata"> for more information.
+
+=item *
+
+It is now a run-time error to use the smart match operator C<~~>
+with an object that has no overload defined for it. (This way
+C<~~> will not break encapsulation by matching against the
+object's internal representation as a reference.)
+
+=item *
+
+The version control system used for the development of the perl
+interpreter has been switched from Perforce to git. This is mainly an
+internal issue that only affects people actively working on the perl core;
+but it may have minor external visibility, for example in some of details
+of the output of C<perl -V>. See L<perlrepository> for more information.
+
+=item *
+
+The internal structure of the C<ext/> directory in the perl source has
+been reorganised. In general, a module C<Foo::Bar> whose source was
+stored under F<ext/Foo/Bar/> is now located under F<ext/Foo-Bar/>. Also,
+nearly all dual-life modules have been moved from F<lib/> to F<ext/>. This
+is purely a source tarball change, and should make no difference to the
+compilation or installation of perl, unless you have a very customised build
+process that explicitly relies on this structure, or which hard-codes the
+C<nonxs_ext> F<Configure> parameter. Specifically, this change does not by
+default alter the location of any files in the final installation.
+
+=item *
+
+As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
+C<Test::Harness::Straps> module has been removed.
+See L</"Updated Modules"> for more details.
+
+=item *
+
+As part of the C<ExtUtils::MakeMaker> upgrade, the
+C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
+have been removed from this distribution.
+
+=item *
+
+C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
+
+=item *
+
+This one is actually a change introduced in 5.10.0, but it was missed
+from that release's perldelta, so it is mentioned here instead.
+
+A bugfix related to the handling of the C</m> modifier and C<qr> resulted
+in a change of behaviour between 5.8.x and 5.10.0:
+
+ # matches in 5.8.x, doesn't match in 5.10.0
+ $re = qr/^bar/; "foo\nbar" =~ /$re/m;
+
+=item *
+
+C<length undef> now returns undef.
+
+=item *
+
+Unsupported private C API functions are now declared "static" to prevent
+leakage to Perl's public API.
+
+=item *
+
+To support the bootstrapping process, F<miniperl> no longer builds with
+UTF-8 support in the regexp engine.
+
+This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
+Without this there's a bootstrapping problem, as miniperl can't load the UTF-8
+components of the regexp engine, because they're not yet built.
+
+=item *
+
+F<miniperl>'s @INC is now restricted to just -I..., the split of $ENV{PERL5LIB}, and "."
+
+=item *
+
+A space or a newline is now required after a C<"#line XXX"> directive.
+
+=item *
+
+Tied filehandles now have an additional method EOF which provides the EOF type
+
+=item *
+
+To better match all other flow control statements, C<foreach> may no longer be used as an attribute.
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Unicode Character Database 5.1.0
+
+The copy of the Unicode Character Database included in Perl 5.11.0 has
+been updated to 5.1.0 from 5.0.0. See
+L<http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes> for the
+notable changes.
+
+=head2 A proper interface for pluggable Method Resolution Orders
+
+As of Perl 5.11.0 there is a new interface for plugging and using method
+resolution orders other than the default (linear depth first search).
+The C3 method resolution order added in 5.10.0 has been re-implemented as
+a plugin, without changing its Perl-space interface. See L<perlmroapi> for
+more information.
+
+=head2 The C<overloading> pragma
+
+This pragma allows you to lexically disable or enable overloading
+for some or all operations. (Yuval Kogman)
+
+=head2 C<\N> regex escape
+
+A new regex escape has been added, C<\N>. It will match any character that
+is not a newline, independently from the presence or absence of the single
+line match modifier C</s>. (If C<\N> is followed by an opening brace and
+by a letter, perl will still assume that a Unicode character name is
+coming, so compatibility is preserved.) (Rafael Garcia-Suarez)
+
+=head2 Implicit strictures
+
+Using the C<use VERSION> syntax with a version number greater or equal
+to 5.11.0 will also lexically enable strictures just like C<use strict>
+would do (in addition to enabling features.) So, the following:
+
+ use 5.11.0;
+
+will now imply:
+
+ use strict;
+ use feature ':5.11';
+
+=head2 Parallel tests
+
+The core distribution can now run its regression tests in parallel on
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
+your environment to the number of tests to run in parallel, and run
+C<make test_harness>. On a Bourne-like shell, this can be done as
+
+ TEST_JOBS=3 make test_harness # Run 3 tests in parallel
+
+An environment variable is used, rather than parallel make itself, because
+L<TAP::Harness> needs to be able to schedule individual non-conflicting test
+scripts itself, and there is no standard interface to C<make> utilities to
+interact with their job schedulers.
+
+Note that currently some test scripts may fail when run in parallel (most
+notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
+again sequentially and see if the failures go away.
+
+=head2 The C<...> operator
+
+A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
+It is intended to mark placeholder code, that is not yet implemented.
+See L<perlop/"Yada Yada Operator">. (chromatic)
+
+=head2 DTrace support
+
+Some support for DTrace has been added. See "DTrace support" in F<INSTALL>.
+
+=head2 Support for C<configure_requires> in CPAN module metadata
+
+Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires> keyword
+in the F<META.yml> metadata file included in most recent CPAN distributions.
+This allows distribution authors to specify configuration prerequisites that
+must be installed before running F<Makefile.PL> or F<Build.PL>.
+
+See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for more
+on how to specify C<configure_requires> when creating a distribution for CPAN.
+
+=head2 C<each> is now more flexible
+
+The C<each> function can now operate on arrays.
+
+=head2 Y2038 compliance
+
+Perl's core time-related functions are now Y2038 compliant. (With 29
+years to spare!)
+
+=head2 C<$,> flexibility
+
+The variable C<$,> may now be tied.
+
+=head2 // in where clauses
+
+// now behaves like || in when clauses
+
+=head2 Enabling warnings from your shell environment
+
+You can now set C<-W> from the C<PERL5OPT> environment variable
+
+=head2 C<delete local>
+
+C<delete local> now allows you to locally delete a hash entry.
+
+=head2 New support for Abstract namespace sockets
+
+Abstract namespace sockets are Linux-specific socket type that live in
+AF_UNIX family, slightly abusing it to be able to use arbitrary
+character arrays as addresses: They start with nul byte and are not
+terminated by nul byte, but with the length passed to the socket()
+system call.
+
+=head1 Modules and Pragmata
+
+=head2 Dual-lifed modules moved
+
+Dual-lifed modules maintained primarily in the Perl core now live in dist/.
+Dual-lifed modules maintained primarily on CPAN now live in cpan/
+
+In previous releases of Perl, it was customary to enumerate all module
+changes in this section of the C<perldelta> file. From 5.11.0 forward
+only notable updates (such as new or deprecated modules ) will be
+listed in this section. For a complete reference to the versions of
+modules shipped in a given release of perl, please see L<Module::CoreList>.
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item C<autodie>
+
+This is a new lexically-scoped alternative for the C<Fatal> module.
+The bundled version is 2.06_01. Note that in this release, using a string
+eval when C<autodie> is in effect can cause the autodie behaviour to leak
+into the surrounding scope. See L<autodie/"BUGS"> for more details.
+
+=item C<Compress::Raw::Bzip2>
+
+This has been added to the core (version 2.020).
+
+=item C<parent>
+
+This pragma establishes an ISA relationship with base classes at compile
+time. It provides the key feature of C<base> without the feature creep.
+
+=item C<Parse::CPAN::Meta>
+
+This has been added to the core (version 1.39).
+
+=back
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<overloading>
+
+See L</"The C<overloading> pragma"> above.
+
+=item C<attrs>
+
+The C<attrs> pragma has been removed. It had been marked as deprecated since
+5.6.0.
+
+=item C<charnames>
+
+The Unicode F<NameAliases.txt> database file has been added. This has the
+effect of adding some extra C<\N> character names that formerly wouldn't
+have been recognised; for example, C<"\N{LATIN CAPITAL LETTER GHA}">.
+
+=item C<feature>
+
+The meaning of the C<:5.10> and C<:5.10.X> feature bundles has
+changed slightly. The last component, if any (i.e. C<X>) is simply ignored.
+This is predicated on the assumption that new features will not, in
+general, be added to maintenance releases. So C<:5.10> and C<:5.10.X>
+have identical effect. This is a change to the behaviour documented for
+5.10.0.
+
+=item C<mro>
+
+Upgraded from version 1.00 to 1.01. Performance for single inheritance is 40%
+faster - see L</"Performance Enhancements"> below.
+
+C<mro> is now implemented as an XS extension. The documented interface has not
+changed. Code relying on the implementation detail that some C<mro::>
+methods happened to be available at all times gets to "keep both pieces".
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<ExtUtils::MakeMaker>
+
+Upgraded from version 6.42 to 6.55_02.
+
+Note that C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish>
+have been removed from this distribution.
+
+=item C<Test::Harness>
+
+Upgraded from version 2.64 to 3.17.
+
+Note that one side-effect of the 2.x to 3.x upgrade is that the
+experimental C<Test::Harness::Straps> module (and its supporting
+C<Assert>, C<Iterator>, C<Point> and C<Results> modules) have been
+removed. If you still need this, then they are available in the
+(unmaintained) C<Test-Harness-Straps> distribution on CPAN.
+
+=item C<UNIVERSAL>
+
+Upgraded from version 1.04 to 1.05.
+
+C<< UNIVERSAL-E<gt>import() >> is now deprecated.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item F<h2ph>
+
+Now looks in C<include-fixed> too, which is a recent addition to gcc's
+search path.
+
+=item F<h2xs>
+
+No longer incorrectly treats enum values like macros (Daniel Burr).
+
+Now handles C++ style constants (C<//>) properly in enums. (A patch from
+Rainer Weikusat was used; Daniel Burr also proposed a similar fix).
+
+=item F<perl5db.pl>
+
+C<LVALUE> subroutines now work under the debugger.
+
+The debugger now correctly handles proxy constant subroutines, and
+subroutine stubs.
+
+=item F<perlbug>
+
+F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out upstream bug
+tracker URLs.
+
+Where the user names a module that their bug report is about, and we know the
+URL for its upstream bug tracker, provide a message to the user explaining
+that the core copies the CPAN version directly, and provide the URL for
+reporting the bug directly to upstream.
+
+=item F<perlthanks>
+
+Perl 5.11.0 added a new utility F<perlthanks>, which is a variant of
+F<perlbug>, but for sending non-bug-reports to the authors and maintainers
+of Perl. Getting nothing but bug reports can become a bit demoralising:
+we'll see if this changes things.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item L<perlhaiku>
+
+This contains instructions on how to build perl for the Haiku platform.
+
+=item L<perlmroapi>
+
+This describes the new interface for pluggable Method Resolution Orders.
+
+=item L<perlperf>
+
+This document, by Richard Foley, provides an introduction to the use of
+performance and optimization techniques which can be used with particular
+reference to perl programs.
+
+=item L<perlrepository>
+
+This describes how to access the perl source using the I<git> version
+control system.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+The various large F<Changes*> files (which listed every change made to perl
+over the last 18 years) have been removed, and replaced by a small file,
+also called F<Changes>, which just explains how that same information may
+be extracted from the git version control system.
+
+The file F<Porting/patching.pod> has been deleted, as it mainly described
+interacting with the old Perforce-based repository, which is now obsolete.
+Information still relevant has been moved to L<perlrepository>.
+
+L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
+generated at build time, rather than being shipped as part of the release.
+
+=over
+
+=item *
+
+Documented -X overloading.
+
+=item *
+
+Documented that C<when()> treats specially most of the filetest operators
+
+=item *
+
+Documented when as a syntax modifier
+
+=item *
+
+Eliminated "Old Perl threads tutorial", which describes 5005 threads.
+
+F<pod/perlthrtut.pod> is the same material reworked for ithreads.
+
+=item *
+
+Correct previous documentation: v-strings are not deprecated
+
+With version objects, we need them to use MODULE VERSION syntax. This
+patch removes the deprecation note.
+
+=item *
+
+Added security contact information to L<perlsec>
+
+=back
+
+=head1 Performance Enhancements
+
+
+=over 4
+
+=item *
+
+A new internal cache means that C<isa()> will often be faster.
+
+=item *
+
+The implementation of C<C3> Method Resolution Order has been optimised -
+linearisation for classes with single inheritance is 40% faster. Performance
+for multiple inheritance is unchanged.
+
+=item *
+
+Under C<use locale>, the locale-relevant information is now cached on
+read-only values, such as the list returned by C<keys %hash>. This makes
+operations such as C<sort keys %hash> in the scope of C<use locale> much
+faster.
+
+=item *
+
+Empty C<DESTROY> methods are no longer called.
+
+=item *
+
+Faster C<Perl_sv_utf8_upgrade()>
+
+=item *
+
+Speed up C<keys> on empty hash
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 F<ext/> reorganisation
+
+The layout of directories in F<ext> has been revised. Specifically, all
+extensions are now flat, and at the top level, with C</> in pathnames
+replaced by C<->, so that F<ext/Data/Dumper/> is now F<ext/Data-Dumper/>,
+etc. The names of the extensions as specified to F<Configure>, and as
+reported by C<%Config::Config> under the keys C<dynamic_ext>,
+C<known_extensions>, C<nonxs_ext> and C<static_ext> have not changed, and
+still use C</>. Hence this change will not have any affect once perl is
+installed. C<Safe> has been split out from being part of C<Opcode>, and
+C<mro> is now an extension in its own right.
+
+Nearly all dual-life modules have been moved from F<lib> to F<ext>, and will
+now appear as known C<nonxs_ext>. This will made no difference to the
+structure of an installed perl, nor will the modules installed differ,
+unless you run F<Configure> with options to specify an exact list of
+extensions to build. In this case, you will rapidly become aware that you
+need to add to your list, because various modules needed to complete the
+build, such as C<ExtUtils::ParseXS>, have now become extensions, and
+without them the build will fail well before it attempts to run the
+regression tests.
+
+=head2 Configuration improvements
+
+If C<vendorlib> and C<vendorarch> are the same, then they are only added to
+C<@INC> once.
+
+C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
+perl is built with C<-Dusedevel>.
+
+F<Configure> will enable use of C<-fstack-protector>, to provide protection
+against stack-smashing attacks, if the compiler supports it.
+
+F<Configure> will now determine the correct prototypes for re-entrant
+functions, and for C<gconvert>, if you are using a C++ compiler rather
+than a C compiler.
+
+On Unix, if you build from a tree containing a git repository, the
+configuration process will note the commit hash you have checked out, for
+display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
+are automatically added to the list of local patches displayed by
+C<perl -V>.
+
+=head2 Compilation improvements
+
+As part of the flattening of F<ext>, all extensions on all platforms are
+built by F<make_ext.pl>. This replaces the Unix-specific
+F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
+F<win32/buildext.pl>.
+
+=head2 Platform Specific Changes
+
+=over 4
+
+=item AIX
+
+Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from F<libbsd>.
+
+Removed F<libgdbm> for AIX 5L and 6.1. The F<libgdbm> is delivered as an
+optional package with the AIX Toolbox. Unfortunately the 64 bit version
+is broken.
+
+Hints changes mean that AIX 4.2 should work again.
+
+=item Cygwin
+
+On Cygwin we now strip the last number from the DLL. This has been the
+behaviour in the cygwin.com build for years. The hints files have been
+updated.
+
+=item DomainOS
+
+Support for Apollo DomainOS was removed in Perl 5.11.0
+
+=item FreeBSD
+
+The hints files now identify the correct threading libraries on FreeBSD 7
+and later.
+
+=item Irix
+
+We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
+C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
+
+=item Haiku
+
+Patches from the Haiku maintainers have been merged in. Perl should now
+build on Haiku.
+
+=item MachTen
+
+Support for Tenon Intersystems MachTen Unix layer for MacOS Classic was
+removed in Perl 5.11.0
+
+=item MiNT
+
+Support for Atari MiNT was removed in Perl 5.11.0.
+
+=item MirOS BSD
+
+Perl should now build on MirOS BSD.
+
+=item NetBSD
+
+Hints now supports versions 5.*.
+
+=item Stratus VOS
+
+Various changes from Stratus have been merged in.
+
+=item Symbian
+
+There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
+
+=item Win32
+
+Improved message window handling means that C<alarm> and C<kill> messages
+will no longer be dropped under race conditions.
+
+=item VMS
+
+Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
+if C<$/> was set to a numeric reference (to indicate record-style reads).
+This is now fixed.
+
+VMS now supports C<getgrgid>.
+
+Many improvements and cleanups have been made to the VMS file name handling
+and conversion code.
+
+Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
+status in a VMS condition value for better interaction with GNV's bash
+shell and other utilities that depend on POSIX exit values. See
+L<perlvms/"$?"> for details.
+
+C<File::Copy> now detects Unix compatibility mode on VMS.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+C<-I> on shebang line now adds directories in front of @INC
+as documented, and as does C<-I> when specified on the command-line.
+
+=item *
+
+C<kill> is now fatal when called on non-numeric process identifiers.
+Previously, an 'undef' process identifier would be interpreted as a request to
+kill process "0", which would terminate the current process group on POSIX
+systems. Since process identifiers are always integers, killing a non-numeric
+process is now fatal.
+
+=item *
+
+5.10.0 inadvertently disabled an optimisation, which caused a measurable
+performance drop in list assignment, such as is often used to assign
+function parameters from C<@_>. The optimisation has been re-instated, and
+the performance regression fixed.
+
+=item *
+
+Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
+
+=item *
+
+Some potential coredumps in PerlIO fixed [RT #57322,54828].
+
+=item *
+
+The debugger now works with lvalue subroutines.
+
+=item *
+
+The debugger's C<m> command was broken on modules that defined constants
+[RT #61222].
+
+=item *
+
+C<crypt> and string complement could return tainted values for untainted
+arguments [RT #59998].
+
+=item *
+
+The C<-i>I<.suffix> command-line switch now recreates the file using
+restricted permissions, before changing its mode to match the original
+file. This eliminates a potential race condition [RT #60904].
+
+=item *
+
+On some Unix systems, the value in C<$?> would not have the top bit set
+(C<$? & 128>) even if the child core dumped.
+
+=item *
+
+Under some circumstances, C<$^R> could incorrectly become undefined
+[RT #57042].
+
+=item *
+
+In the XS API, various hash functions, when passed a pre-computed hash where
+the key is UTF-8, might result in an incorrect lookup.
+
+=item *
+
+XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
+[RT #57176].
+
+=item *
+
+C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo> didn't
+exist, even if the object's C<@ISA> contained C<Foo>.
+
+=item *
+
+Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
+C<@ISA>, have been found and fixed.
+
+=item *
+
+Bitwise operations on references could crash the interpreter, e.g.
+C<$x=\$y; $x |= "foo"> [RT #54956].
+
+=item *
+
+Patterns including alternation might be sensitive to the internal UTF-8
+representation, e.g.
+
+ my $byte = chr(192);
+ my $utf8 = chr(192); utf8::upgrade($utf8);
+ $utf8 =~ /$byte|X}/i; # failed in 5.10.0
+
+=item *
+
+Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
+effect), double-quoted literal strings could be corrupted where a C<\xNN>,
+C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
+greater than 255 [RT #59908].
+
+=item *
+
+C<B::Deparse> failed to correctly deparse various constructs:
+C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
+C<sub foo(_)> [RT #62484].
+
+=item *
+
+Using C<setpgrp> with no arguments could corrupt the perl stack.
+
+=item *
+
+The block form of C<eval> is now specifically trappable by C<Safe> and
+C<ops>. Previously it was erroneously treated like string C<eval>.
+
+=item *
+
+In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
+match operator (C<~~>) [RT #63854].
+
+=item *
+
+In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
+C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
+
+ ("ab" x 32768) =~ /^(ab)*$/
+
+=item *
+
+C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
+
+=item *
+
+Using C<next> or C<last> to exit a C<given> block no longer produces a
+spurious warning like the following:
+
+ Exiting given via last at foo.pl line 123
+
+=item *
+
+On Windows, C<'.\foo'> and C<'..\foo'> were treated differently than
+C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
+
+=item *
+
+Assigning a format to a glob could corrupt the format; e.g.:
+
+ *bar=*foo{FORMAT}; # foo format now bad
+
+=item *
+
+Attempting to coerce a typeglob to a string or number could cause an
+assertion failure. The correct error message is now generated,
+C<Can't coerce GLOB to I<$type>>.
+
+=item *
+
+Under C<use filetest 'access'>, C<-x> was using the wrong access mode. This
+has been fixed [RT #49003].
+
+=item *
+
+C<length> on a tied scalar that returned a Unicode value would not be
+correct the first time. This has been fixed.
+
+=item *
+
+Using an array C<tie> inside in array C<tie> could SEGV. This has been
+fixed. [RT #51636]
+
+=item *
+
+A race condition inside C<PerlIOStdio_close()> has been identified and
+fixed. This used to cause various threading issues, including SEGVs.
+
+=item *
+
+In C<unpack>, the use of C<()> groups in scalar context was internally
+placing a list on the interpreter's stack, which manifested in various
+ways, including SEGVs. This is now fixed [RT #50256].
+
+=item *
+
+Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
+These have all been fixed.
+
+=item *
+
+A 5.10.0 optimisation to clear the temporary stack within the implicit
+loop of C<s///ge> has been reverted, as it turned out to be the cause of
+obscure bugs in seemingly unrelated parts of the interpreter [commit
+ef0d4e17921ee3de].
+
+=item *
+
+The line numbers for warnings inside C<elsif> are now correct.
+
+=item *
+
+The C<..> operator now works correctly with ranges whose ends are at or
+close to the values of the smallest and largest integers.
+
+=item *
+
+C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
+This has been fixed [RT #54828].
+
+=item *
+
+An off-by-one error meant that C<index $str, ...> was effectively being
+executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
+
+=item *
+
+Various leaks associated with named captures in regexes have been fixed
+[RT #57024].
+
+=item *
+
+A weak reference to a hash would leak. This was affecting C<DBI>
+[RT #56908].
+
+=item *
+
+Using (?|) in a regex could cause a segfault [RT #59734].
+
+=item *
+
+Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
+
+=item *
+
+Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
+unaligned 64-bit access on the SPARC architecture [RT #60574].
+
+=item *
+
+In the 5.10.0 release, C<inc_version_list> would incorrectly list
+C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
+[RT #67628].
+
+=item *
+
+In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
+[RT #52552].
+
+=item *
+
+In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
+C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
+[RT #62666].
+
+=item *
+
+In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
+missed (method cache issue) [RT #60220,60232].
+
+=item *
+
+In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
+cause a memory leak [RT #63110].
+
+=item *
+
+C<-C> on the shebang (C<#!>) line is once more permitted if it is also
+specified on the command line. C<-C> on the shebang line used to be a
+silent no-op I<if> it was not also on the command line, so perl 5.10.0
+disallowed it, which broke some scripts. Now perl checks whether it is
+also on the command line and only dies if it is not [RT #67880].
+
+=item *
+
+In 5.10.0, certain types of re-entrant regular expression could crash,
+or cause the following assertion failure [RT #60508]:
+
+ Assertion rx->sublen >= (s - rx->subbeg) + i failed
+
+=item *
+
+Previously missing files from Unicode 5.1 Character Database are now included.
+
+=item *
+
+C<TMPDIR> is now honored when opening an anonymous temporary file
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item C<panic: sv_chop %s>
+
+This new fatal error occurs when the C routine C<Perl_sv_chop()> was
+passed a position that is not within the scalar's string buffer. This
+could be caused by buggy XS code, and at this point recovery is not
+possible.
+
+=item C<Can't locate package %s for the parents of %s>
+
+This warning has been removed. In general, it only got produced in
+conjunction with other warnings, and removing it allowed an ISA lookup
+optimisation to be added.
+
+=item C<v-string in use/require is non-portable>
+
+This warning has been removed.
+
+=item C<Deep recursion on subroutine "%s">
+
+It is now possible to change the depth threshold for this warning from the
+default of 100, by recompiling the F<perl> binary, setting the C
+pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+TODO: C<SVt_RV> is gone. RVs are now stored in IVs
+
+=item *
+
+TODO: REGEXPs are first class
+
+=item *
+
+TODO: OOK is reworked, such that an OOKed scalar is PV not PVIV
+
+=item *
+
+The J.R.R. Tolkien quotes at the head of C source file have been checked and
+proper citations added, thanks to a patch from Tom Christiansen.
+
+=item *
+
+C<Perl_vcroak()> now accepts a null first argument. In addition, a full audit
+was made of the "not NULL" compiler annotations, and those for several
+other internal functions were corrected.
+
+=item *
+
+New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
+have been added to formalise the temporary saving of the C<errno>
+variable.
+
+=item *
+
+The function C<Perl_sv_insert_flags> has been added to augment
+C<Perl_sv_insert>.
+
+=item *
+
+The function C<Perl_newSV_type(type)> has been added, equivalent to
+C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
+
+=item *
+
+The function C<Perl_newSVpvn_flags()> has been added, equivalent to
+C<Perl_newSVpvn()> and then performing the action relevant to the flag.
+
+Two flag bits are currently supported.
+
+=over 4
+
+=item C<SVf_UTF8>
+
+This will call C<SvUTF8_on()> for you. (Note that this does not convert an
+sequence of ISO 8859-1 characters to UTF-8). A wrapper, C<newSVpvn_utf8()>
+is available for this.
+
+=item C<SVs_TEMP>
+
+Call C<Perl_sv_2mortal()> on the new SV.
+
+=back
+
+There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
+
+=item *
+
+The function C<Perl_croak_xs_usage> has been added as a wrapper to
+C<Perl_croak>.
+
+=item *
+
+The functions C<PerlIO_find_layer> and C<PerlIO_list_alloc> are now
+exported.
+
+=item *
+
+C<PL_na> has been exterminated from the core code, replaced by local STRLEN
+temporaries, or C<*_nolen()> calls. Either approach is faster than C<PL_na>,
+which is a pointer deference into the interpreter structure under ithreads,
+and a global variable otherwise.
+
+=item *
+
+C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()> on
+the scalar. It now updates the linked list to remove each piece of magic
+as it is freed.
+
+=item *
+
+Under ithreads, the regex in C<PL_reg_curpm> is now reference counted. This
+eliminates a lot of hackish workarounds to cope with it not being reference
+counted.
+
+=item *
+
+C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
+This has been fixed.
+
+=item *
+
+The I<public> IV and NV flags are now not set if the string value has
+trailing "garbage". This behaviour is consistent with not setting the
+public IV or NV flags if the value is out of range for the type.
+
+=item *
+
+SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
+The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
+that was enabled when the F<perl> binary was compiled.
+
+=item *
+
+Smartmatch resolution tracing has been added as a new diagnostic. Use C<-DM> to
+enable it.
+
+
+=item *
+
+A new debugging flag C<-DB> now dumps subroutine definitions, leaving
+C<-Dx> for its original purpose of dumping syntax trees.
+
+=item *
+
+Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have been
+replaced by C<NULL> in the core code, and non-dual-life modules, as C<NULL>
+is clearer to those unfamiliar with the core code.
+
+=item *
+
+A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
+not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
+C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
+casting away C<const>. This allows proper compile-time auditing of
+C<const> correctness in the core, and helped picked up some errors (now
+fixed).
+
+=item *
+
+Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
+stack and mortalizing them.
+
+=item *
+
+Use of the private structure C<mro_meta> has changed slightly. Nothing
+outside the core should be accessing this directly anyway.
+
+=item *
+
+A new tool, F<Porting/expand-macro.pl> has been added, that allows you
+to view how a C preprocessor macro would be expanded when compiled.
+This is handy when trying to decode the macro hell that is the perl
+guts.
+
+=back
+
+=head1 New Tests
+
+Many modules updated from CPAN incorporate new tests.
+
+Several tests that have the potential to hang forever if they fail now
+incorporate a "watchdog" functionality that will kill them after a timeout,
+which helps ensure that C<make test> and C<make test_harness> run to
+completion automatically. (Jerry Hedden).
+
+Some core-specific tests have been added:
+
+=over 4
+
+=item t/comp/retainedlines.t
+
+Check that the debugger can retain source lines from C<eval>.
+
+=item t/io/perlio_fail.t
+
+Check that bad layers fail.
+
+=item t/io/perlio_leaks.t
+
+Check that PerlIO layers are not leaking.
+
+=item t/io/perlio_open.t
+
+Check that certain special forms of open work.
+
+=item t/io/perlio.t
+
+General PerlIO tests.
+
+=item t/io/pvbm.t
+
+Check that there is no unexpected interaction between the internal types
+C<PVBM> and C<PVGV>.
+
+=item t/mro/package_aliases.t
+
+Check that mro works properly in the presence of aliased packages.
+
+=item t/op/dbm.t
+
+Tests for C<dbmopen> and C<dbmclose>.
+
+=item t/op/index_thr.t
+
+Tests for the interaction of C<index> and threads.
+
+=item t/op/pat_thr.t
+
+Tests for the interaction of esoteric patterns and threads.
+
+=item t/op/qr_gc.t
+
+Test that C<qr> doesn't leak.
+
+=item t/op/reg_email_thr.t
+
+Tests for the interaction of regex recursion and threads.
+
+=item t/op/regexp_qr_embed_thr.t
+
+Tests for the interaction of patterns with embedded C<qr//> and threads.
+
+=item t/op/regexp_unicode_prop.t
+
+Tests for Unicode properties in regular expressions.
+
+=item t/op/regexp_unicode_prop_thr.t
+
+Tests for the interaction of Unicode properties and threads.
+
+=item t/op/reg_nc_tie.t
+
+Test the tied methods of C<Tie::Hash::NamedCapture>.
+
+=item t/op/reg_posixcc.t
+
+Check that POSIX character classes behave consistently.
+
+=item t/op/re.t
+
+Check that exportable C<re> functions in F<universal.c> work.
+
+=item t/op/setpgrpstack.t
+
+Check that C<setpgrp> works.
+
+=item t/op/substr_thr.t
+
+Tests for the interaction of C<substr> and threads.
+
+=item t/op/upgrade.t
+
+Check that upgrading and assigning scalars works.
+
+=item t/uni/lex_utf8.t
+
+Check that Unicode in the lexer works.
+
+=item t/uni/tie.t
+
+Check that Unicode and C<tie> work.
+
+=back
+
+=head1 Known Problems
+
+This is a list of some significant unfixed bugs, which are regressions
+from either 5.10.0 or 5.8.x.
+
+=over 4
+
+=item *
+
+C<List::Util::first> misbehaves in the presence of a lexical C<$_>
+(typically introduced by C<my $_> or implicitly by C<given>). The variable
+which gets set for each iteration is the package variable C<$_>, not the
+lexical C<$_> [RT #67694].
+
+A similar issue may occur in other modules that provide functions which
+take a block as their first argument, like
+
+ foo { ... $_ ...} list
+
+=item *
+
+The C<charnames> pragma may generate a run-time error when a regex is
+interpolated [RT #56444]:
+
+ use charnames ':full';
+ my $r1 = qr/\N{THAI CHARACTER SARA I}/;
+ "foo" =~ $r1; # okay
+ "foo" =~ /$r1+/; # runtime error
+
+A workaround is to generate the character outside of the regex:
+
+ my $a = "\N{THAI CHARACTER SARA I}";
+ my $r1 = qr/$a/;
+
+=item *
+
+Some regexes may run much more slowly when run in a child thread compared
+with the thread the pattern was compiled into [RT #55600].
+
+=back
+
+=head1 Deprecations
+
+The following items are now deprecated.
+
+=over 4
+
+=item *
+
+C<Switch> is buggy and should be avoided. From perl 5.11.0 onwards, it is
+intended that any use of the core version of this module will emit a
+warning, and that the module will eventually be removed from the core
+(probably in perl 5.14.0). See L<perlsyn/"Switch statements"> for its
+replacement.
+
+=item *
+
+The following modules will be removed from the core distribution in a future
+release, and should be installed from CPAN instead. Distributions on CPAN
+which require these should add them to their prerequisites. The core versions
+of these modules warnings will issue a deprecation warning.
+
+=over
+
+=item *
+
+C<Class::ISA>
+
+=item *
+
+C<Pod::Plainer>
+
+=item *
+
+C<Shell>
+
+=back
+
+Currently support to install from CPAN without a I<force> is C<TODO> in CPAN
+and CPANPLUS. This will be addressed before 5.12.0 ships.
+
+=item *
+
+C<suidperl> has been removed. It used to provide a mechanism to
+emulate setuid permission bits on systems that don't support it properly.
+
+=item *
+
+Deprecate assignment to $[
+
+=item *
+
+Remove attrs, which has been deprecated since 1999/10/02.
+
+=item *
+
+Deprecate use of the attribute :locked on subroutines.
+
+=item *
+
+Deprecate using "locked" with the attributes pragma.
+
+=item *
+
+Deprecate using "unique" with the attributes pragma.
+
+=item *
+
+warn if ++ or -- are unable to change the value because it's beyond the limit of representation
+
+This uses a new warnings category: "imprecision".
+
+=item *
+
+Make lc/uc/lcfirst/ucfirst warn when passed undef.
+
+=item *
+
+Show constant in "Useless use of a constant in void context"
+
+=item *
+
+Make the new warning report undef constants as undef
+
+=item *
+
+Add a new warning, "Prototype after '%s'"
+
+=item *
+
+Tweak the "Illegal character in prototype" warning so it's more precise when reporting illegal characters after _
+
+=item *
+
+Unintended interpolation of $\ in regex
+
+=item *
+
+Make overflow warnings in gmtime/localtime only occur when warnings are on
+
+=item *
+
+Improve mro merging error messages.
+
+They are now very similar to those produced by Algorithm::C3.
+
+=item *
+
+Amelioration of the error message "Unrecognized character %s in column %d"
+
+Changes the error message to "Unrecognized character %s; marked by E<lt>--
+HERE after %sE<lt>-- HERE near column %d". This should make it a little
+simpler to spot and correct the suspicious character.
+
+=item *
+
+Explicitely point to $. when it causes an uninitialized warning for ranges in scalar context
+
+
+=item *
+
+Deprecated numerous Perl 4-era libraries:
+
+F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
+F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
+F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
+F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
+F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
+F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
+F<timelocal.pl> are all now deprecated. Using them will incur a warning.
+
+=back
+
+=head1 Acknowledgements
+
+Some of the work in this release was funded by a TPF grant funded by
+Dijkmat BV, The Netherlands.
+
+Steffen Mueller and David Golden in particular helped getting CPAN modules
+polished and synchronised with their in-core equivalents.
+
+Craig Berry was tireless in getting maint to run under VMS, no matter how
+many times we broke it for him.
+
+The other core committers contributed most of the changes, and applied most
+of the patches sent in by the hundreds of contributors listed in F<AUTHORS>.
+
+Much of the work of categorizing changes in this perldelta file was contributed
+by the following porters using changelogger.bestpractical.com:
+
+Nicholas Clark, leon, shawn, alexm, rjbs, rafl, Pedro Melo, brunorc,
+anonymous, ☄, Tom Hukins, anonymous, Jesse, dagolden, Moritz Onken,
+Mark Fowler, chorny, anonymous, tmtm
+
+Finally, thanks to Larry Wall, without whom none of this would be
+necessary.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5111delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5111delta.pod
new file mode 100644
index 00000000000..4717374803d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5111delta.pod
@@ -0,0 +1,365 @@
+=head1 NAME
+
+perl5111delta - what is new for perl v5.11.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.11.0 release and
+the 5.11.1 release.
+
+=head1 Incompatible Changes
+
+=over
+
+=item *
+
+The boolkeys op moved to the group of hash ops. This breaks binary compatibility.
+
+=item *
+
+C<\s> C<\w> and C<\d> once again have the semantics they had in Perl 5.8.x.
+
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Add C<package NAME VERSION> syntax
+
+This new syntax allows a module author to set the $VERSION of a namespace
+when the namespace is declared with 'package'. It eliminates the need
+for C<our $VERSION = ...> and similar constructs. E.g.
+
+ package Foo::Bar 1.23;
+ # $Foo::Bar::VERSION == 1.23
+
+There are several advantages to this:
+
+=over
+
+=item *
+
+C<$VERSION> is parsed in I<exactly> the same way as C<use NAME VERSION>
+
+=item *
+
+C<$VERSION> is set at compile time
+
+=item *
+
+Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
+
+=item *
+
+As it requires VERSION to be a numeric literal or v-string
+literal, it can be statically parsed by toolchain modules
+without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
+
+=item *
+
+Alpha versions with underscores do not need to be quoted; static
+parsing will preserve the underscore, but during compilation, Perl
+will remove underscores as it does for all numeric literals
+
+It does not break old code with only C<package NAME>, but code that uses
+C<package NAME VERSION> will need to be restricted to perl 5.11.X or newer
+This is analogous to the change to C<open> from two-args to three-args.
+Users requiring the latest Perl will benefit, and perhaps N years from
+now it will become standard practice when Perl 5.12 is targeted the way
+that 5.6 is today.
+
+=back
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules
+
+=over 4
+
+=item *
+
+Upgrade to Test-Simple 0.94
+
+=item *
+
+Upgrade to Storable 2.21
+
+=item *
+
+Upgrade to Pod-Simple 3.08
+
+=item *
+
+Upgrade to Parse-CPAN-Meta 1.40
+
+=item *
+
+Upgrade to ExtUtils-Manifest 1.57
+
+=item *
+
+Upgrade to ExtUtils-CBuilder 0.260301
+
+=item *
+
+Upgrade to CGI.pm-3.48
+
+=item *
+
+Upgrade CPANPLUS to CPAN version 0.89_02
+
+=item *
+
+Upgrade to threads::shared 1.32
+
+=item *
+
+Upgrade ExtUtils::ParseXS to 2.21
+
+=item *
+
+Upgrade File::Path to 2.08 (and add taint.t test)
+
+=item *
+
+Upgrade Module::CoreList to 2.20
+
+=item *
+
+Updated Object::Accessor to0.36
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item *
+
+L<perlpolicy> extends the "Social contract about contributed modules" into
+the beginnings of a document on Perl porting policies.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+=over
+
+=item Documentation for C<$1> in perlvar.pod clarified
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>
+
+=back
+
+=head1 Platform Specific Notes
+
+=over 4
+
+=item Darwin (Mac OS X)
+
+=over 4
+
+=item *
+
+Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
+as it's still buggy.
+
+=item *
+
+Correct infelicities in the regexp used to identify buggy locales
+on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
+
+=back
+
+=item DragonFly BSD
+
+=over 4
+
+=item *
+
+Fix thread library selection [perl #69686]
+
+=back
+
+=item Win32
+
+=over 4
+
+=item *
+
+Initial support for mingw64 is now available
+
+=item *
+
+Various bits of Perl's build infrastructure are no longer converted to win32 line endings at release time. If this hurts you, please speak up.
+
+=back
+
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Perl now properly returns a syntax error instead of segfaulting
+if C<each>, C<keys> or C<values> is used without an argument
+
+=item *
+
+C<tell()> now fails properly if called without an argument and when no previous file was read
+
+C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring the 5.8.x behaviour
+
+=item *
+
+overload no longer implicitly unsets fallback on repeated 'use overload' lines
+
+=item *
+
+POSIX::strftime() can now handle Unicode characters in the format string.
+
+=item *
+
+The Windows select() implementation now supports all empty C<fd_set>s more correctly.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+
+=item *
+
+The 'syntax' category was removed from 5 warnings that should only be in 'deprecated'.
+
+=item *
+
+Three fatal pack/unpack error messages have been normalized to "panic: %s"
+
+=item *
+
+"Unicode character is illegal" has been rephrased to be more accurate
+
+It now reads C<Unicode non-character is illegal in interchange> and the
+perldiag documentation has been expanded a bit.
+
+=item *
+
+Perl now defaults to issuing a warning if a deprecated language feature is used.
+
+To disable this feature in a given lexical scope, you should use C<no
+warnings 'deprecated';> For information about which language features
+are deprecated and explanations of various deprecation warnings, please
+see L<perldiag>
+
+=back
+
+=head1 Testing
+
+=over 4
+
+=item *
+
+Significant cleanups to core tests to ensure that language and
+interpreter features are not used before they're tested.
+
+=item *
+
+C<make test_porting> now runs a number of important pre-commit checks which might be of use to anyone working on the Perl core.
+
+=item *
+
+F<t/porting/podcheck.t> automatically checks the well-formedness of
+POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
+dual-lifed modules which are primarily maintained outside the Perl core.
+
+=item *
+
+F<t/porting/manifest.t> now tests that all files listed in MANIFEST are present.
+
+=back
+
+=head1 Known Problems
+
+=over 4
+
+=item Untriaged test crashes on Windows 2000
+
+Several porters have reported mysterious crashes when Perl's entire test suite is run after a build on certain Windows 2000 systems. When run by hand, the individual tests reportedly work fine.
+
+=item Known test failures on VMS
+
+Perl 5.11.1 fails a small set of core and CPAN tests as of this release.
+With luck, that'll be sorted out for 5.11.2
+
+=back
+
+=head1 Errata for 5.11.0
+
+=over
+
+=item The Perl 5.11.0 release notes incorrectly described 'delete local'
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.11.1 represents approximately 3 weeks development since Perl 5.11.0
+contains 22,000 lines of changes across 396 files from 26 authors and committers:
+
+Abigail, Alex Vandiver, brian d foy, Chris Williams, Craig A. Berry,
+David Fifield, David Golden, demerphq, Eric Brine, Geoffrey T. Dairiki,
+George Greer, H.Merijn Brand, Jan Dubois, Jerry D. Hedden, Jesse Vincent,
+Josh ben Jore, Max Maischein, Nicholas Clark, Rafael Garcia-Suarez,
+Simon Schubert, Sisyphus, Smylers, Steve Hay, Steve Peters, Vincent Pit
+and Yves Orton.
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5112delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5112delta.pod
new file mode 100644
index 00000000000..c53a622c4cc
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5112delta.pod
@@ -0,0 +1,348 @@
+=head1 NAME
+
+perl5112delta - what is new for perl v5.11.2
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.11.1 release and the
+5.11.2 release.
+
+=head1 Core Enhancements
+
+=head2 qr overloading
+
+It is now possible to overload the C<qr//> operator, that is,
+conversion to regexp, like it was already possible to overload
+conversion to boolean, string or number of objects. It is invoked when
+an object appears on the right hand side of the C<=~> operator, or when
+it is interpolated into a regexp. See L<overload>.
+
+=head2 Pluggable keywords
+
+Extension modules can now cleanly hook into the Perl parser to define
+new kinds of keyword-headed expression and compound statement. The
+syntax following the keyword is defined entirely by the extension. This
+allow a completely non-Perl sublanguage to be parsed inline, with the
+right ops cleanly generated. This feature is currently considered
+experimental.
+
+See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
+source distribution also includes a new module
+L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
+arithmetic via pluggable keywords. This module is mainly used for test
+purposes, and is not normally installed, but also serves as an example
+of how to use the new mechanism.
+
+=head2 APIs for more internals
+
+The lowest layers of the lexer and parts of the pad system now have C
+APIs available to XS extensions. These are necessary to support proper
+use of pluggable keywords, but have other uses too. The new APIs are
+experimental, and only cover a small proportion of what would be
+necessary to take full advantage of the core's facilities in these
+areas. It is intended that the Perl 5.13 development cycle will see the
+addition of a full range of clean, supported interfaces.
+
+=head2 Overridable function lookup
+
+Where an extension module hooks the creation of rv2cv ops to modify the
+subroutine lookup process, this now works correctly for bareword
+subroutine calls. This means that prototypes on subroutines referenced
+this way will be processed correctly. (Previously bareword subroutine
+names were initially looked up, for parsing purposes, by an unhookable
+mechanism, so extensions could only properly influence subroutine names
+that appeared with an C<&> sigil.)
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item C<legacy>
+
+Preserves legacy behaviors or enable new non-default behaviors.
+Currently the only behaviour concerns semantics for the 128 characters
+on ASCII systems that have the 8th bit set.
+
+=back
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<diagnostics>
+
+Supports %.0f formatting internally.
+
+=item C<overload>
+
+Allow overloading of 'qr'.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<B::Concise>
+
+Optimize reversing an array in-place, avoid using defined %hash in core
+code and tests.
+
+=item C<B::Deparse>
+
+Teach B::Deparse about in-place reverse.
+
+=item C<Carp>
+
+Refine Carp caller() fix and add tests.
+
+=item C<Compress::Zlib>
+
+Updated to 2.022.
+
+=item C<CPANPLUS>
+
+Updated to 0.89_09.
+
+=item C<Encode>
+
+Updated to 2.38.
+
+=item C<ExtUtils::CBuilder>
+
+Updated to 0.27.
+
+=item C<Env>
+
+Add EXISTS and DELETE methods to Env.pm.
+
+=item C<File::Fetch>
+
+Updated to 0.22.
+
+=item C<I8N::Langinfo>
+
+Correctly document export of I18N::Langinfo.
+
+=item C<I8N::LangTags>
+
+In I18N::LangTags::Detect, avoid using defined @array and defined
+%hash.
+
+=item C<IO::Compress>
+
+Updated to 2.022.
+
+=item C<IPC::Cmd>
+
+Updated to 0.54.
+
+=item C<List::Util>
+
+Updated to 1.22.
+
+=item C<Locale::Maketext>
+
+In Locale::Maketext, avoid using defined @array and defined %hash.
+Convert the odd Locale::Maketext test out from Test to Test::More.
+
+=item C<Module::Build>
+
+Updated to 0.35_08.
+
+=item C<Module::CoreList>
+
+Implemented is_deprecated().
+
+=item C<Pod::Simple>
+
+Updated to 3.10.
+
+=item C<Scalar::Util>
+
+Updated to 1.22.
+
+=item C<Switch>
+
+Updated to 2.16.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item F<a2p>
+
+Fixed bugs with the match() operator in list context, remove mention of
+$[.
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Reversing an array to itself (as in C<@a = reverse @a>) in void context
+now happens in-place and is several orders of magnitude faster than it
+used to be. It will also preserve non-existent elements whenever
+possible, i.e. for non magical arrays or tied arrays with C<EXISTS> and
+C<DELETE> methods.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+Several new diagnostics, see L<perldiag> for details.
+
+=over 4
+
+=item C<Bad plugin affecting keyword '%s'>
+
+=item C<gmtime(%.0f) too large>
+
+=item C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
+
+=item C<Lexing code internal error (%s)>
+
+=item C<localtime(%.0f) too large>
+
+=item C<Overloaded dereference did not return a reference>
+
+=item C<Overloaded qr did not return a REGEXP>
+
+=item C<Perl_pmflag() is deprecated, and will be removed from the XS API>
+
+=back
+
+One diagnostic has been removed:
+
+=over 4
+
+=item C<Runaway format>
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+C<Perl_pmflag> has been removed from the public API. Calling it now
+generates a deprecation warning, and it will be removed in a future
+release. Although listed as part of the API, it was never documented,
+and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
+core, it has been replaced by a static function.
+
+=back
+
+=head1 New Tests
+
+=over 4
+
+=item F<t/op/while_readdir.t>
+
+Test that a bare readdir in while loop sets $_.
+
+=back
+
+=head1 Known Problems
+
+=over 4
+
+=item Known test failures on VMS
+
+Perl 5.11.2 fails a small set of core and CPAN tests as of this
+release. With luck, that'll be sorted out for 5.11.3.
+
+=back
+
+=head1 Deprecations
+
+The following items are now deprecated.
+
+=head2 Use of C<:=> to mean an empty attribute list is now deprecated.
+
+An accident of Perl's parser meant that these constructions were all
+equivalent:
+
+ my $pi := 4;
+ my $pi : = 4;
+ my $pi : = 4;
+
+with the C<:> being treated as the start of an attribute list, which
+ends before the C<=>. As whitespace is not significant here, all are
+parsed as an empty attribute list, hence all the above are equivalent
+to, and better written as
+
+ my $pi = 4;
+
+because no attribute processing is done for an empty list.
+
+As is, this meant that C<:=> cannot be used as a new token, without
+silently changing the meaning of existing code. Hence that particular
+form is now deprecated, and will become a syntax error. If it is
+absolutely necessary to have empty attribute lists (for example,
+because of a code generator) then avoid the warning by adding a space
+before the C<=>.
+
+=head1 Acknowledgements
+
+Perl 5.11.2 represents approximately 3 weeks development since Perl
+5.11.1 and contains 29,992 lines of changes across 458 files from 38
+authors and committers:
+
+Abhijit Menon-Sen, Abigail, Ben Morrow, Bo Borgerson, Brad Gilbert,
+Bram, Chris Williams, Craig A. Berry, Daniel Frederick Crisman, Dave
+Rolsky, David E. Wheeler, David Golden, Eric Brine, Father
+Chrysostomos, Frank Wiegand, Gerard Goossen, Gisle Aas, Graham Barr,
+Harmen, H.Merijn Brand, Jan Dubois, Jerry D. Hedden, Jesse Vincent,
+Karl Williamson, Kevin Ryde, Leon Brocard, Nicholas Clark, Paul
+Marquess, Philippe Bruhat, Rafael Garcia-Suarez, Sisyphus, Steffen
+Mueller, Steve Hay, Steve Peters, Vincent Pit, Yuval Kogman, Yves
+Orton, and Zefram.
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl bug
+database at http://rt.perl.org/perlbug/ . There may also be information
+at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down to a
+tiny but sufficient test case. Your bug report, along with the output
+of C<perl -V>, will be sent off to perlbug@perl.org to be analysed by
+the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please
+send it to perl5-security-report@perl.org. This points to a closed
+subscription unarchived mailing list, which includes all the core
+committers, who be able to help assess the impact of issues, figure out
+a resolution, and help co-ordinate the release of patches to mitigate
+or fix the problem across all platforms on which Perl is supported.
+Please only use this address for security issues in the Perl core, not
+for modules independently distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive
+details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5113delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5113delta.pod
new file mode 100644
index 00000000000..5c4e1966027
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5113delta.pod
@@ -0,0 +1,558 @@
+=head1 NAME
+
+perl5113delta - what is new for perl v5.11.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.11.2 release and
+the 5.11.3 release.
+
+If you are upgrading from an earlier release such as 5.11.1, first read
+the L<perl5112delta>, which describes differences between 5.11.1 and
+5.11.2
+
+=head1 Incompatible Changes
+
+=head2 Filehandles are blessed directly into C<IO::Handle>, as C<FileHandle> is merely a wrapper around C<IO::Handle>.
+
+The previous behaviour was to bless Filehandles into L<FileHandle>
+(an empty proxy class) if it was loaded into memory and otherwise
+to bless them into C<IO::Handle>.
+
+=head1 Core Enhancements
+
+=head2 Unicode version
+
+Perl is shipped with the latest Unicode version, 5.2, dated October 2009. See
+L<http://www.unicode.org/versions/Unicode5.2.0> for details about this release
+of Unicode. See L<perlunicode> for instructions on installing and using
+older versions of Unicode.
+
+=head2 Unicode properties
+
+Perl can now handle every Unicode character property. A new pod,
+L<perluniprops>, lists all available non-Unihan character properties. By
+default the Unihan properties and certain others (deprecated and Unicode
+internal-only ones) are not exposed. See below for more details on
+these; there is also a section in the pod listing them, and why they are
+not exposed.
+
+Perl now fully supports the Unicode compound-style of using C<=> and C<:>
+in writing regular expressions: C<\p{property=value}> and
+C<\p{property:value}> (both of which mean the same thing).
+
+Perl now fully supports the Unicode loose matching rules for text
+between the braces in C<\p{...}> constructs. In addition, Perl also allows
+underscores between digits of numbers.
+
+All the Unicode-defined synonyms for properties and property values are
+now accepted.
+
+C<qr/\X/>, which matches a Unicode logical character, has been expanded to work
+better with various Asian languages. It now is defined as an C<extended
+grapheme cluster>. (See L<http://www.unicode.org/reports/tr29/>).
+Anything matched previously that made sense will continue to be matched. But
+in addition:
+
+=over
+
+=item *
+
+C<\X> will now not break apart a C<S<CR LF>> sequence.
+
+=item *
+
+C<\X> will now match a sequence including the C<ZWJ> and C<ZWNJ> characters.
+
+=item *
+
+C<\X> will now always match at least one character, including an initial mark.
+Marks generally come after a base character, but it is possible in Unicode to
+have them in isolation, and C<\X> will now handle that case, for example at the
+beginning of a line or after a C<ZWSP>. And this is the part where C<\X>
+doesn't match the things that it used to that don't make sense. Formerly, for
+example, you could have the nonsensical case of an accented LF.
+
+=item *
+
+C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai and Lao
+exception cases.
+
+=back
+
+Otherwise, this change should be transparent for the non-affected languages.
+
+C<\p{...}> matches using the Canonical_Combining_Class property were
+completely broken in previous Perls. This is now fixed.
+
+In previous Perls, the Unicode C<Decomposition_Type=Compat> property and a
+Perl extension had the same name, which led to neither matching all the
+correct values (with more than 100 mistakes in one, and several thousand
+in the other). The Perl extension has now been renamed to be
+C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the same
+meaning as was previously intended, namely the union of all the
+non-canonical Decomposition types, with Unicode C<Compat> being just one of
+those.
+
+C<\p{Uppercase}> and C<\p{Lowercase}> have been brought into line with the
+Unicode definitions. This means they each match a few more characters
+than previously.
+
+C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This means it
+no longer will match Private Use (gc=co), Surrogates (gc=cs), nor Format
+(gc=cf) code points. The Format code points represent the biggest
+possible problem. All but 36 of them are either officially deprecated
+or strongly discouraged from being used. Of those 36, likely the most
+widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ, WJ, and
+similar, plus Bi-directional controls.
+
+C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. The Perl
+definition included a number of things that aren't really alpha (all
+marks), while omitting many that were. As a direct consequence, the
+definitions of C<\p{Alnum}> and C<\p{Word}> which depend on Alpha also change.
+
+C<\p{Word}> also now doesn't match certain characters it wasn't supposed
+to, such as fractions.
+
+C<\p{Print}> no longer matches the line control characters: Tab, LF, CR,
+FF, VT, and NEL. This brings it in line with the documentation.
+
+C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
+
+The Numeric type property has been extended to include the Unihan
+characters.
+
+There is a new Perl extension, the 'Present_In', or simply 'In',
+property. This is an extension of the Unicode Age property, but
+C<\p{In=5.0}> matches any code point whose usage has been determined
+I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
+added in I<precisely> version 5.0.
+
+A number of properties did not have the correct values for unassigned
+code points. This is now fixed. The affected properties are
+Bidi_Class, East_Asian_Width, Joining_Type, Decomposition_Type,
+Hangul_Syllable_Type, Numeric_Type, and Line_Break.
+
+The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
+have been updated to their current Unicode definitions.
+
+Certain properties that are supposed to be Unicode internal-only were
+erroneously exposed by previous Perls. Use of these in regular
+expressions will now generate, if enabled, a deprecated warning message.
+The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
+Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
+Other_Math, and Other_Uppercase.
+
+An installation can now fairly easily change which Unicode properties
+Perl understands. As mentioned above, certain properties are by default
+turned off. These include all the Unihan properties (which should be
+accessible via the CPAN module Unicode::Unihan) and any deprecated or
+Unicode internal-only property that Perl has never exposed.
+
+The generated files in the C<lib/unicore/To> directory are now more
+clearly marked as being stable, directly usable by applications.
+New hash entries in them give the format of the normal entries,
+which allows for easier machine parsing. Perl can generate files
+in this directory for any property, though most are suppressed. An
+installation can choose to change which get written. Instructions
+are in L<perluniprops>.
+
+=head2 Regular Expressions
+
+U+0FFFF is now a legal character in regular expressions.
+
+=head1 Modules and Pragmata
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<constant>
+
+Upgraded from version 1.19 to 1.20.
+
+=item C<diagnostics>
+
+This pragma no longer suppresses C<Use of uninitialized value in range (or flip)> warnings. [perl #71204]
+
+=item C<feature>
+
+Upgraded from 1.13 to 1.14. Added the C<unicode_strings> feature:
+
+ use feature "unicode_strings";
+
+This pragma turns on Unicode semantics for the case-changing operations
+(uc/lc/ucfirst/lcfirst) on strings that don't have the internal UTF-8 flag set,
+but that contain single-byte characters between 128 and 255.
+
+=item C<legacy>
+
+The experimental C<legacy> pragma, introduced in 5.11.2, has been removed,
+and its functionality replaced by the new feature pragma, C<use feature
+"unicode_strings">.
+
+=item C<threads>
+
+Upgraded from version 1.74 to 1.75.
+
+=item C<warnings>
+
+Upgraded from 1.07 to 1.08. Added new C<warnings::fatal_enabled()> function.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Archive::Extract>
+
+Upgraded from version 0.34 to 0.36.
+
+=item C<CPAN>
+
+Upgraded from version 1.94_51 to 1.94_5301, which is 1.94_53 on CPAN
+plus some local fixes for bleadperl.
+
+Includes better bzip2 support, improved FirstTime experience with
+auto-selection of CPAN mirrors, proper handling of modules removed from the
+Perl core, and an updated 'cpan' utility script
+
+=item C<CPANPLUS>
+
+Upgraded from version 0.89_09 to 0.90.
+
+=item C<Encode>
+
+Upgraded from version 2.38 to 2.39.
+
+=item C<ExtUtils::MakeMaker>
+
+Upgraded from version 6.55_02 to 6.56. Adds new BUILD_REQUIRES key to
+indicate build-only prerequisites. Also adds support for
+mingw64 and the new "package NAME VERSION" syntax.
+
+=item C<File::Path>
+
+Upgraded from version 2.08 to 2.08_01.
+
+=item C<Module::Build>
+
+Upgraded from version 0.35_09 to 0.36. Compared to 0.35, this version has a
+new 'installdeps' action, supports the PERL_MB_OPT environment variable, adds a
+'share_dir' property for L<File::ShareDir> support, support the "package NAME
+VERSION" syntax and has many other enhancements and bug fixes. The
+'passthrough' style of Module::Build::Compat has been deprecated.
+
+=item C<Module::CoreList>
+
+Upgraded from version 2.23 to 2.24.
+
+=item C<POSIX>
+
+Upgraded from version 1.18 to 1.19. Error codes for C<getaddrinfo()> and
+C<getnameinfo()> are now available.
+
+=item C<Pod::Simple>
+
+Upgraded from version 3.10 to 3.13.
+
+=item C<Safe>
+
+Upgraded from version 2.19 to 2.20.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item F<perlbug>
+
+No longer reports "Message sent" when it hasn't actually sent the message
+
+=back
+
+=head1 Changes to Existing Documentation
+
+The Pod specification (L<perlpodspec>) has been updated to bring the
+specification in line with modern usage already supported by most Pod systems.
+A parameter string may now follow the format name in a "begin/end" region.
+Links to URIs with a text description are now allowed. The usage of
+C<LE<lt>"section"E<gt>> has been marked as deprecated.
+
+L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
+conditional loading of modules despite the implicit BEGIN block around C<use>.
+
+
+
+=head1 Installation and Configuration Improvements
+
+=head2 Testing improvements
+
+=over 4
+
+=item It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
+
+=back
+
+=head2 Platform Specific Changes
+
+=over 4
+
+=item Win32
+
+=over 4
+
+=item *
+
+Always add a manifest resource to C<perl.exe> to specify the C<trustInfo>
+settings for Windows Vista and later. Without this setting Windows
+will treat C<perl.exe> as a legacy application and apply various
+heuristics like redirecting access to protected file system areas
+(like the "Program Files" folder) to the users "VirtualStore"
+instead of generating a proper "permission denied" error.
+
+For VC8 and VC9 this manifest setting is automatically generated by
+the compiler/linker (together with the binding information for their
+respective runtime libraries); for all other compilers we need to
+embed the manifest resource explicitly in the external resource file.
+
+This change also requests the Microsoft Common-Controls version 6.0
+(themed controls introduced in Windows XP) via the dependency list
+in the assembly manifest. For VC8 and VC9 this is specified using the
+C</manifestdependency> linker commandline option instead.
+
+=back
+
+=item cygwin
+
+=over 4
+
+=item Enable IPv6 support on cygwin 1.7 and newer
+
+=back
+
+=item OpenVMS
+
+=over 4
+
+=item Make -UDEBUGGING the default on VMS for 5.12.0.
+
+Like it has been everywhere else for ages and ages. Also make
+command-line selection of -UDEBUGGING and -DDEBUGGING work in
+configure.com; before the only way to turn it off was by saying
+no in answer to the interactive question.
+
+=back
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Ensure that pp_qr returns a new regexp SV each time. Resolves RT #69852.
+
+Instead of returning a(nother) reference to the (pre-compiled) regexp in the
+optree, use reg_temp_copy() to create a copy of it, and return a reference to
+that. This resolves issues about Regexp::DESTROY not being called in a timely
+fashion (the original bug tracked by RT #69852), as well as bugs related to
+blessing regexps, and of assigning to regexps, as described in correspondence
+added to the ticket.
+
+It transpires that we also need to undo the SvPVX() sharing when ithreads
+cloning a Regexp SV, because mother_re is set to NULL, instead of a cloned
+copy of the mother_re. This change might fix bugs with regexps and threads in
+certain other situations, but as yet neither tests nor bug reports have
+indicated any problems, so it might not actually be an edge case that it's
+possible to reach.
+
+=item *
+
+Several compilation errors and segfaults when perl was built with C<-Dmad> were fixed.
+
+=item *
+
+Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
+
+=item *
+
+F<-t> should only return TRUE for file handles connected to a TTY
+
+The Microsoft C version of isatty() returns TRUE for all
+character mode devices, including the /dev/null style "nul"
+device and printers like "lpt1".
+
+=item *
+
+Fixed a regression caused by commit fafafbaf which caused a panic during
+parameter passing [perl #70171]
+
+=item *
+
+On systems which in-place edits without backup files, -i'*' now works as
+the documentation says it does [perl #70802]
+
+=item *
+
+Saving and restoring magic flags no longer loses readonly flag.
+
+=item *
+
+The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
+causes abrupt and total failure.
+
+=item *
+
+Regular expressions compiled with C<qr{}> literals properly set C<$'> when
+matching again.
+
+=item *
+
+Using named subroutines with C<sort> should no longer lead to bus errors [perl
+#71076]
+
+=item *
+
+Numerous bugfixes catch small issues caused by the recently-added Lexer API.
+
+=item *
+
+Smart match against C<@_> sometimes gave false negatives. [perl #71078]
+
+=item *
+
+C<$@> may now be assigned a read-only value (without error or busting the stack).
+
+=item *
+
+C<sort> called recursively from within an active comparison subroutine no
+longer causes a bus error if run multiple times. [perl #71076]
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item *
+
+C<split> now warns when called in void context
+
+=item *
+
+C<printf>-style functions called with too few arguments will now issue the
+warning C<"Missing argument in %s"> [perl #71000]
+
+=back
+
+=head1 New Tests
+
+Many modules updated from CPAN incorporate new tests.
+
+=over 4
+
+=item t/comp/final_line_num.t
+
+See if line numbers are correct at EOF
+
+=item t/comp/form_scope.t
+
+See if format scoping works
+
+=item t/comp/line_debug.t
+
+See if @{"_<$file"} works
+
+=item t/op/filetest_t.t
+
+See if -t file test works
+
+=item t/op/qr.t
+
+See if qr works
+
+=item t/op/utf8cache.t
+
+Tests malfunctions of utf8 cache
+
+=item t/re/uniprops.t
+
+Test unicode \p{} regex constructs
+
+=back
+
+=head1 Deprecations
+
+The following items are now deprecated.
+
+=over 4
+
+=item Use of "goto" to jump into a construct is deprecated
+
+Using C<goto> to jump from an outer scope into an inner
+scope is now deprecated. This rare use case was causing
+problems in the implementation of scopes.
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.11.3 represents approximately one month of development since
+Perl 5.11.2 and contains 61407 lines of changes across 396 files
+from 40 authors and committers:
+
+Abigail, Alex Davies, Alexandr Ciornii, Andrew Rodland, Andy
+Dougherty, Bram, brian d foy, Chip Salzenberg, Chris Williams, Craig
+A. Berry, Daniel Frederick Crisman, David Golden, Dennis Kaarsemaker,
+Eric Brine, Father Chrysostomos, Gene Sullivan, Gerard Goossen, H.
+Merijn Brand, Hugo van der Sanden, Jan Dubois, Jerry D. Hedden,
+Jesse Vincent, Jim Cromie, Karl Williamson, Leon Brocard, Max
+Maischein, Michael Breen, Moritz Lenz, Nicholas Clark, Rafael
+Garcia-Suarez, Reini Urban, Ricardo Signes, Stepan Kasal, Steve
+Hay, Steve Peters, Tim Bunce, Tony Cook, Vincent Pit and Zefram.
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5114delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5114delta.pod
new file mode 100644
index 00000000000..05a387f2d37
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5114delta.pod
@@ -0,0 +1,278 @@
+=head1 NAME
+
+perl5114delta - what is new for perl v5.11.4
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.11.3 release and
+the 5.11.4 release.
+
+If you are upgrading from an earlier release such as 5.11.2, first read
+L<perl5113delta>, which describes differences between 5.11.2 and
+5.11.3.
+
+=head1 Incompatible Changes
+
+=head2 Version number formats
+
+Acceptable version number formats have been formalized into "strict" and
+"lax" rules. C<package NAME VERSION> takes a strict version number. C<use
+NAME VERSION> takes a lax version number. C<UNIVERSAL::VERSION> and the
+L<version> object constructors take lax version numbers. Providing an
+invalid version will result in a fatal error.
+
+These formats will be documented fully in the L<version> module in a
+subsequent release of Perl 5.11. To a first approximation, a "strict"
+version number is a positive decimal number (integer or decimal-fraction)
+without exponentiation or else a dotted-decimal v-string with a leading 'v'
+character and at least three components. A "lax" version number allows
+v-strings with fewer than three components or without a leading 'v'. Under
+"lax" rules, both decimal and dotted-decimal versions may have a trailing
+"alpha" component separated by an underscore character after a fractional
+or dotted-decimal component.
+
+The L<version> module adds C<version::is_strict> and C<version::is_lax>
+functions to check a scalar against these rules.
+
+=head1 Core Enhancements
+
+=head2 Unicode properties
+
+C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
+means that in addition to the characters it currently matches,
+C<[A-Fa-f0-9]>, it will also match their fullwidth equivalent forms, for
+example U+FF10: FULLWIDTH DIGIT ZERO.
+
+=head1 Modules and Pragmata
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<less>
+
+Upgraded from version 0.02 to 0.03.
+
+This version introduces the C<stash_name> method to allow subclasses of less to
+pick where in %^H to store their stash.
+
+=item C<version>
+
+Upgraded from version 0.77 to 0.81.
+
+This version adds support for L</Version number formats> as described earlier
+in this document and in its own documentation.
+
+=item C<warnings>
+
+Upgraded from version 1.08 to 1.09.
+
+This version adds the C<illegalproto> warning category. See also L</New or
+Changed Diagnostics> for this change.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Archive::Extract>
+
+Upgraded from version 0.36 to 0.38.
+
+=item C<B::Deparse>
+
+Upgraded from version 0.93 to 0.94.
+
+=item C<Compress::Raw::Bzip2>
+
+Upgraded from version 2.021 to 2.024.
+
+=item C<Compress::Raw::Zlib>
+
+Upgraded from version 2.021 to 2.024.
+
+=item C<CPAN>
+
+Upgraded from version 1.94_5301 to 1.94_54.
+
+=item C<File::Fetch>
+
+Upgraded from version 0.22 to 0.24.
+
+=item C<Module::Build>
+
+Upgraded from version 0.36 to 0.3603.
+
+=item C<Safe>
+
+Upgraded from version 2.20 to 2.21.
+
+Anonymous coderefs created in Safe containers no longer get bogus
+arguments passed to them, fixing RT #72068.
+
+=back
+
+=head2 Removed Modules and Pragmata
+
+=over 4
+
+=item C<Devel::DProf::V>
+
+Removed from the Perl core. Prior version was 'undef'.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+A significant fraction of the core documentation has been updated to clarify
+the behavior of Perl's Unicode handling.
+
+Much of the remaining core documentation has been reviewed and edited
+for clarity, consistent use of language, and to fix the spelling of Tom
+Christiansen's name.
+
+=head2 Configuration improvements
+
+USE_ATTRIBUTES_FOR_PERLIO is now reported in the compile-time options
+listed by the C<-V> switch.
+
+=head2 Platform Specific Changes
+
+=over 4
+
+=item VMS
+
+The default pipe buffer size on VMS has been updated to 8192 on 64-bit
+systems.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Tie::Hash::NamedCapture::* shouldn't abort if passed bad input (RT #71828)
+
+=item *
+
+@_ and $_ no longer leak under threads (RT #34342 and #41138, also
+#70602, #70974)
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item New warning category C<illegalproto>
+
+The two warnings :
+
+ Illegal character in prototype for %s : %s
+ Prototype after '%c' for %s : %s
+
+have been moved from the C<syntax> top-level warnings category into a new
+first-level category, C<illegalproto>. These two warnings are currently the
+only ones emitted during parsing of an invalid/illegal prototype, so one
+can now do
+
+ no warnings 'illegalproto';
+
+to suppress only those, but not other syntax-related warnings. Warnings where
+prototypes are changed, ignored, or not met are still in the C<prototype>
+category as before. (Matt S. Trout)
+
+=item lvalue attribute ignored after the subroutine has been defined
+
+This new warning is issued when one attempts to mark a subroutine as
+lvalue after it has been defined.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+Perl_magic_setmglob now knows about globs, fixing RT #71254.
+
+=back
+
+=head1 Known Problems
+
+Perl 5.11.4 is a development release leading up to Perl 5.12.0.
+Some notable known problems found in 5.11.4 are listed as dependencies
+of RT #69710, the Perl 5 version 12 meta-ticket.
+
+=head1 Deprecations
+
+The following items are now deprecated.
+
+=over 4
+
+=item C<< UNIVERSAL-E<gt>import() >>
+
+The method C<< UNIVERSAL-E<gt>import() >> is now deprecated. Attempting to
+pass import arguments to a C<use UNIVERSAL> statement will result in a
+deprecation warning. (This is a less noisy version of the full deprecation
+warning added in 5.11.0.)
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.11.4 represents approximately one month of development since
+Perl 5.11.3 and contains 17682 lines of changes across 318 files
+from 40 authors and committers:
+
+Abigail, Andy Dougherty, brian d foy, Chris Williams, Craig A. Berry,
+David Golden, David Mitchell, Father Chrysostomos, Gerard Goossen,
+H.Merijn Brand, Jesse Vincent, Jim Cromie, Josh ben Jore, Karl
+Williamson, kmx, Matt S Trout, Nicholas Clark, Niko Tyni, Paul Marquess,
+Philip Hazel, Rafael Garcia-Suarez, Rainer Tammer, Reini Urban, Ricardo
+Signes, Shlomi Fish, Tim Bunce, Todd Rinaldo, Tom Christiansen, Tony
+Cook, Vincent Pit, and Zefram
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at L<http://rt.perl.org/perlbug/>. There may also be
+information at L<http://www.perl.org/>, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analyzed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5115delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5115delta.pod
new file mode 100644
index 00000000000..bb4180220ea
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5115delta.pod
@@ -0,0 +1,327 @@
+=head1 NAME
+
+perl5115delta - what is new for perl v5.11.5
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.11.4 release and
+the 5.11.5 release.
+
+If you are upgrading from an earlier release such as 5.11.3, first read
+L<perl5114delta>, which describes differences between 5.11.3 and
+5.11.4.
+
+=head1 Core Enhancements
+
+=head2 32-bit limit on substr arguments removed
+
+The 32-bit limit on C<substr> arguments has now been removed. The full range
+of the system's signed and unsigned integers is now available for the C<pos>
+and C<len> arguments.
+
+=head1 Modules and Pragmata
+
+=head2 Pragmata Changes
+
+=over 4
+
+=item C<version>
+
+Upgraded from version 0.81 to 0.82.
+
+The C<is_lax> and C<is_strict> functions can now be optionally exported to the
+caller's namespace and are also now documented.
+
+Undefined version objects are now uninitialized with zero rather than C<undef>.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<B::Debug>
+
+Upgraded from version 1.11 to 1.12.
+
+=item C<CPAN>
+
+Upgraded from version 1.94_53 to 1.94_56.
+
+This resolves RT #72362, in which CPAN was ignoring C<configure_requires>,
+and RT #72348, in which the command C<o conf init> in the CPAN shell could
+cause an exception to be thrown.
+
+This module is also now built in a less specialized way, which resolves a
+problem that caused C<make> after C<make clean> to fail, fixing RT #72218.
+
+=item C<CPANPLUS::Dist::Build>
+
+Upgraded from version 0.44 to 0.46.
+
+This makes the prereq resolving fall back to F<_build/> querying if the
+C<prereq_data> action fails.
+
+=item C<Pod::Perldoc>
+
+Upgraded from version 3.15_01 to 3.15_02.
+
+=item C<Pod::Plainer>
+
+Upgraded from version 1.01 to 1.02.
+
+=item C<Safe>
+
+Upgraded from version 2.21 to 2.22.
+
+This resolves RT #72700, in which an exception thrown from a closure was
+getting lost.
+
+=item C<Socket>
+
+Upgraded from version 1.85 to 1.86.
+
+This makes the new Socket implementation of C<inet_pton> consistent with the
+existing Socket6 implementation of C<inet_pton>, fixing RT #72884.
+
+=item C<podlators>
+
+Upgraded from version 2.2.2 to 2.3.1.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid, as
+is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK>,
+although actually using the latter may not be the best idea for the
+readability of your source code.
+
+=head1 Installation and Configuration Improvements
+
+=head2 Configuration improvements
+
+Support for SystemTap's C<dtrace> compatibility layer has been added and an
+issue with linking C<miniperl> has been fixed in the process.
+
+C<less -R> is now used instead of C<less> for C<groff>'s new usage of ANSI
+escape codes by setting C<$Config{less}> (and thereby C<$Config{pager}>,
+which fixes RT #72156.
+
+USE_PERL_ATOF is now reported in the compile-time options listed by the C<-V>
+switch.
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Arbitrary whitespace is now allowed between C<NAME> and C<VERSION> in
+C<package NAME VERSION;> statements. (Fixes RT #72432)
+
+=item *
+
+A panic caused by trying to load C<charnames> when the parser is already in
+error (e.g. by a missing C<my> under C<use strict;>) is now averted. This
+was a regression since Perl 5.10.0. (Fixes RT #72590)
+
+=item *
+
+Reading C<$!> no longer causes a SEGV for out of range C<errno> values. (Fixes
+RT #72850)
+
+=item *
+
+A possible SEGV in C</\N{...}/> has been fixed. This was a regression since
+Perl 5.10.
+
+=item *
+
+A possible SEGV when freeing a scalar that was upgraded to an C<SVt_REGEXP>
+type from a simple(r) scalar has been fixed.
+
+=item *
+
+A type conversion bug in C<gmtime64> that caused it to break around C<2**48>
+has been fixed.
+
+=item *
+
+Interpolating a regex that makes use of the C<charnames> pragma will no longer
+cause a run-time error. (Fixes RT #56444)
+
+=item *
+
+Array references assigned to C<*Foo::ISA> now have the necessary magic added
+to them to catch any further updates to the new C<@ISA>. (Fixes RT #72866)
+
+=item *
+
+Filehandles are now always blessed into C<IO::File>, which, together with
+some suitable manipulation of C<@IO::File::ISA>, fixes a breakage introduced
+in Perl 5.11.3 by a change that always blessed filehandles into C<IO::Handle>
+rather than checking for C<FileHandle> first.
+
+=item *
+
+A change in the behaviour of C<warnings::enabled> and C<warnings::warnif> in
+Perl 5.10.0 that wasn't documented at the time is now documented in
+L<perl5100delta>. (Fixes RT #62522)
+
+=item *
+
+RT #71504 is now fixed by simply skipping the tests that failed on OpenBSD
+with ithreads and perlio.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item *
+
+The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
+C<charnames> handler returns malformed UTF-8.
+
+=item *
+
+If an unresolved named character or sequence was encountered when compiling a
+regex pattern then the fatal error C<\\N{NAME} must be resolved by the lexer>
+is now produced. This can happen, for example, when using a single-quotish
+context like C<$re = '\N{SPACE}'; $re;>. See L<perldiag> for more examples of
+how the lexer can get bypassed.
+
+=item *
+
+The fatal error C<Invalid hexadecimal number in \\N{U+...}> will be produced
+if the character constant represented by C<...> is not a valid hexadecimal
+number.
+
+=item *
+
+The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
+class, just like C<.> in a character class loses its special meaning, and will
+cause the fatal error C<\\N in a character class must be a named character:
+\\N{...}>.
+
+=item *
+
+The rules on what is legal for the C<...> in C<\N{...}> have been tightened
+up so that unless the C<...> begins with an alphabetic character and continues
+with a combination of alphanumerics, dashes, spaces, parentheses or colons
+then the warning C<Deprecated character(s) in \\N{...} starting at '%s'> is
+now issued.
+
+=item *
+
+The warning C<Using just the first characters returned by \N{}> will be
+issued if the C<charnames> handler returns a sequence of characters which
+exceeds the limit of the number of characters that can be used. The message
+will indicate which characters were used and which were discarded.
+
+=item *
+
+Currently, all but the first of the several characters that the C<charnames>
+handler may return are discarded when used in a regular expression pattern
+bracketed character class. If this happens then the warning C<Using just the
+first character returned by \N{} in character class> will be issued.
+
+=item *
+
+The warning C<Missing right brace on \\N{} or unescaped left brace after \\N.
+Assuming the latter> will be issued if Perl encounters a C<\N{> but doesn't
+find a matching C<}>. In this case Perl doesn't know if it was mistakenly
+omitted, or if "match non-newline" followed by "match a C<{>" was desired.
+It assumes the latter because that is actually a valid interpretation as
+written, unlike the other case. If you meant the former, you need to add the
+matching right brace. If you did mean the latter, you can silence this
+warning by writing instead C<\N\{>.
+
+=item *
+
+C<gmtime> and C<localtime> called with numbers smaller than they can reliably
+handle will now issue the warnings C<gmtime(%.0f) too small> and
+C<localtime(%.0f) too small>.
+
+=back
+
+=head1 New Tests
+
+=over 4
+
+=item F<t/op/filehandle.t>
+
+Tests some suitably portable filetest operators to check that they work as
+expected, particularly in the light of some internal changes made in how
+filehandles are blessed.
+
+=item F<t/op/time_loop.t>
+
+Tests that times greater than C<2**63>, which can now be handed to C<gmtime>
+and C<localtime>, do not cause an internal overflow or an excessively long
+loop.
+
+=back
+
+=head1 Known Problems
+
+Perl 5.11.5 is a development release leading up to Perl 5.12.0.
+Some notable known problems found in 5.11.5 are listed as dependencies
+of RT #69710, the Perl 5 version 12 meta-ticket.
+
+=head1 Acknowledgements
+
+Perl 5.11.5 represents approximately one month of development since
+Perl 5.11.4 and contains 9618 lines of changes across 151 files
+from 33 authors and committers:
+
+E<AElig>var ArnfjE<ouml>rE<eth> Bjarmason, Abigail, brian d foy, Chris
+Williams, David Golden, David Mitchell, Eric Brine, Frank Wiegand, Gisle
+Aas, H.Merijn Brand, Jan Dubois, Jesse Vincent, Jim Cromie, John Peacock,
+Josh ben Jore, Karl Williamson, Marcus Holland-Moritz, Michael G Schwern,
+Nicholas Clark, Offer Kaye, Philippe Bruhat (BooK), Rafael Garcia-Suarez,
+Reini Urban, Ricardo Signes, Robin Barker, Slaven Rezic, Steffen Mueller,
+Steve Hay, Steve Peters, Tim Bunce, Todd Rinaldo, Tony Cook and
+Vincent Pit.
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analyzed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5120delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5120delta.pod
new file mode 100644
index 00000000000..5d5b401e784
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5120delta.pod
@@ -0,0 +1,3200 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5120delta - what is new for perl v5.12.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.10.0 release and the
+5.12.0 release.
+
+Many of the bug fixes in 5.12.0 are already included in the 5.10.1
+maintenance release.
+
+You can see the list of those changes in the 5.10.1 release notes
+(L<perl5101delta>).
+
+
+=head1 Core Enhancements
+
+=head2 New C<package NAME VERSION> syntax
+
+This new syntax allows a module author to set the $VERSION of a namespace
+when the namespace is declared with 'package'. It eliminates the need
+for C<our $VERSION = ...> and similar constructs. E.g.
+
+ package Foo::Bar 1.23;
+ # $Foo::Bar::VERSION == 1.23
+
+There are several advantages to this:
+
+=over
+
+=item *
+
+C<$VERSION> is parsed in exactly the same way as C<use NAME VERSION>
+
+=item *
+
+C<$VERSION> is set at compile time
+
+=item *
+
+C<$VERSION> is a version object that provides proper overloading of
+comparison operators so comparing C<$VERSION> to decimal (1.23) or
+dotted-decimal (v1.2.3) version numbers works correctly.
+
+=item *
+
+Eliminates C<$VERSION = ...> and C<eval $VERSION> clutter
+
+=item *
+
+As it requires VERSION to be a numeric literal or v-string
+literal, it can be statically parsed by toolchain modules
+without C<eval> the way MM-E<gt>parse_version does for C<$VERSION = ...>
+
+=back
+
+It does not break old code with only C<package NAME>, but code that uses
+C<package NAME VERSION> will need to be restricted to perl 5.12.0 or newer
+This is analogous to the change to C<open> from two-args to three-args.
+Users requiring the latest Perl will benefit, and perhaps after several
+years, it will become a standard practice.
+
+
+However, C<package NAME VERSION> requires a new, 'strict' version
+number format. See L<"Version number formats"> for details.
+
+
+=head2 The C<...> operator
+
+A new operator, C<...>, nicknamed the Yada Yada operator, has been added.
+It is intended to mark placeholder code that is not yet implemented.
+See L<perlop/"Yada Yada Operator">.
+
+=head2 Implicit strictures
+
+Using the C<use VERSION> syntax with a version number greater or equal
+to 5.11.0 will lexically enable strictures just like C<use strict>
+would do (in addition to enabling features.) The following:
+
+ use 5.12.0;
+
+means:
+
+ use strict;
+ use feature ':5.12';
+
+=head2 Unicode improvements
+
+Perl 5.12 comes with Unicode 5.2, the latest version available to
+us at the time of release. This version of Unicode was released in
+October 2009. See L<http://www.unicode.org/versions/Unicode5.2.0> for
+further details about what's changed in this version of the standard.
+See L<perlunicode> for instructions on installing and using other versions
+of Unicode.
+
+Additionally, Perl's developers have significantly improved Perl's Unicode
+implementation. For full details, see L</Unicode overhaul> below.
+
+=head2 Y2038 compliance
+
+Perl's core time-related functions are now Y2038 compliant. (It may not mean much to you, but your kids will love it!)
+
+=head2 qr overloading
+
+It is now possible to overload the C<qr//> operator, that is,
+conversion to regexp, like it was already possible to overload
+conversion to boolean, string or number of objects. It is invoked when
+an object appears on the right hand side of the C<=~> operator or when
+it is interpolated into a regexp. See L<overload>.
+
+=head2 Pluggable keywords
+
+Extension modules can now cleanly hook into the Perl parser to define
+new kinds of keyword-headed expression and compound statement. The
+syntax following the keyword is defined entirely by the extension. This
+allow a completely non-Perl sublanguage to be parsed inline, with the
+correct ops cleanly generated.
+
+See L<perlapi/PL_keyword_plugin> for the mechanism. The Perl core
+source distribution also includes a new module
+L<XS::APItest::KeywordRPN>, which implements reverse Polish notation
+arithmetic via pluggable keywords. This module is mainly used for test
+purposes, and is not normally installed, but also serves as an example
+of how to use the new mechanism.
+
+Perl's developers consider this feature to be experimental. We may remove
+it or change it in a backwards-incompatible way in Perl 5.14.
+
+=head2 APIs for more internals
+
+The lowest layers of the lexer and parts of the pad system now have C
+APIs available to XS extensions. These are necessary to support proper
+use of pluggable keywords, but have other uses too. The new APIs are
+experimental, and only cover a small proportion of what would be
+necessary to take full advantage of the core's facilities in these
+areas. It is intended that the Perl 5.13 development cycle will see the
+addition of a full range of clean, supported interfaces.
+
+Perl's developers consider this feature to be experimental. We may remove
+it or change it in a backwards-incompatible way in Perl 5.14.
+
+=head2 Overridable function lookup
+
+Where an extension module hooks the creation of rv2cv ops to modify the
+subroutine lookup process, this now works correctly for bareword
+subroutine calls. This means that prototypes on subroutines referenced
+this way will be processed correctly. (Previously bareword subroutine
+names were initially looked up, for parsing purposes, by an unhookable
+mechanism, so extensions could only properly influence subroutine names
+that appeared with an C<&> sigil.)
+
+=head2 A proper interface for pluggable Method Resolution Orders
+
+As of Perl 5.12.0 there is a new interface for plugging and using method
+resolution orders other than the default linear depth first search.
+The C3 method resolution order added in 5.10.0 has been re-implemented as
+a plugin, without changing its Perl-space interface. See L<perlmroapi> for
+more information.
+
+
+
+=head2 C<\N> experimental regex escape
+
+Perl now supports C<\N>, a new regex escape which you can think of as
+the inverse of C<\n>. It will match any character that is not a newline,
+independently from the presence or absence of the single line match
+modifier C</s>. It is not usable within a character class. C<\N{3}>
+means to match 3 non-newlines; C<\N{5,}> means to match at least 5.
+C<\N{NAME}> still means the character or sequence named C<NAME>, but
+C<NAME> no longer can be things like C<3>, or C<5,>.
+
+This will break a L<custom charnames translator|charnames/CUSTOM
+TRANSLATORS> which allows numbers for character names, as C<\N{3}> will
+now mean to match 3 non-newline characters, and not the character whose
+name is C<3>. (No name defined by the Unicode standard is a number,
+so only custom translators might be affected.)
+
+Perl's developers are somewhat concerned about possible user confusion
+with the existing C<\N{...}> construct which matches characters by their
+Unicode name. Consequently, this feature is experimental. We may remove
+it or change it in a backwards-incompatible way in Perl 5.14.
+
+=head2 DTrace support
+
+Perl now has some support for DTrace. See "DTrace support" in F<INSTALL>.
+
+=head2 Support for C<configure_requires> in CPAN module metadata
+
+Both C<CPAN> and C<CPANPLUS> now support the C<configure_requires>
+keyword in the F<META.yml> metadata file included in most recent CPAN
+distributions. This allows distribution authors to specify configuration
+prerequisites that must be installed before running F<Makefile.PL>
+or F<Build.PL>.
+
+See the documentation for C<ExtUtils::MakeMaker> or C<Module::Build> for
+more on how to specify C<configure_requires> when creating a distribution
+for CPAN.
+
+=head2 C<each> is now more flexible
+
+The C<each> function can now operate on arrays.
+
+=head2 C<when> as a statement modifier
+
+C<when> is now allowed to be used as a statement modifier.
+
+=head2 C<$,> flexibility
+
+The variable C<$,> may now be tied.
+
+=head2 // in when clauses
+
+// now behaves like || in when clauses
+
+=head2 Enabling warnings from your shell environment
+
+You can now set C<-W> from the C<PERL5OPT> environment variable
+
+=head2 C<delete local>
+
+C<delete local> now allows you to locally delete a hash entry.
+
+=head2 New support for Abstract namespace sockets
+
+Abstract namespace sockets are Linux-specific socket type that live in
+AF_UNIX family, slightly abusing it to be able to use arbitrary
+character arrays as addresses: They start with nul byte and are not
+terminated by nul byte, but with the length passed to the socket()
+system call.
+
+=head2 32-bit limit on substr arguments removed
+
+The 32-bit limit on C<substr> arguments has now been removed. The full
+range of the system's signed and unsigned integers is now available for
+the C<pos> and C<len> arguments.
+
+=head1 Potentially Incompatible Changes
+
+=head2 Deprecations warn by default
+
+Over the years, Perl's developers have deprecated a number of language
+features for a variety of reasons. Perl now defaults to issuing a
+warning if a deprecated language feature is used. Many of the deprecations
+Perl now warns you about have been deprecated for many years. You can
+find a list of what was deprecated in a given release of Perl in the
+C<perl5xxdelta.pod> file for that release.
+
+To disable this feature in a given lexical scope, you should use C<no
+warnings 'deprecated';> For information about which language features
+are deprecated and explanations of various deprecation warnings, please
+see L<perldiag>. See L</Deprecations> below for the list of features
+and modules Perl's developers have deprecated as part of this release.
+
+=head2 Version number formats
+
+Acceptable version number formats have been formalized into "strict" and
+"lax" rules. C<package NAME VERSION> takes a strict version number.
+C<UNIVERSAL::VERSION> and the L<version> object constructors take lax
+version numbers. Providing an invalid version will result in a fatal
+error. The version argument in C<use NAME VERSION> is first parsed as a
+numeric literal or v-string and then passed to C<UNIVERSAL::VERSION>
+(and must then pass the "lax" format test).
+
+These formats are documented fully in the L<version> module. To a first
+approximation, a "strict" version number is a positive decimal number
+(integer or decimal-fraction) without exponentiation or else a
+dotted-decimal v-string with a leading 'v' character and at least three
+components. A "lax" version number allows v-strings with fewer than
+three components or without a leading 'v'. Under "lax" rules, both
+decimal and dotted-decimal versions may have a trailing "alpha"
+component separated by an underscore character after a fractional or
+dotted-decimal component.
+
+The L<version> module adds C<version::is_strict> and C<version::is_lax>
+functions to check a scalar against these rules.
+
+=head2 @INC reorganization
+
+In C<@INC>, C<ARCHLIB> and C<PRIVLIB> now occur after after the current
+version's C<site_perl> and C<vendor_perl>. Modules installed into
+C<site_perl> and C<vendor_perl> will now be loaded in preference to
+those installed in C<ARCHLIB> and C<PRIVLIB>.
+
+
+=head2 REGEXPs are now first class
+
+Internally, Perl now treates compiled regular expressions (such as
+those created with C<qr//>) as first class entities. Perl modules which
+serialize, deserialize or otherwise have deep interaction with Perl's
+internal data structures need to be updated for this change. Most
+affected CPAN modules have already been updated as of this writing.
+
+=head2 Switch statement changes
+
+The C<given>/C<when> switch statement handles complex statements better
+than Perl 5.10.0 did (These enhancements are also available in
+5.10.1 and subsequent 5.10 releases.) There are two new cases where
+C<when> now interprets its argument as a boolean, instead of an
+expression to be used in a smart match:
+
+=over
+
+=item flip-flop operators
+
+The C<..> and C<...> flip-flop operators are now evaluated in boolean
+context, following their usual semantics; see L<perlop/"Range Operators">.
+
+Note that, as in perl 5.10.0, C<when (1..10)> will not work to test
+whether a given value is an integer between 1 and 10; you should use
+C<when ([1..10])> instead (note the array reference).
+
+However, contrary to 5.10.0, evaluating the flip-flop operators in
+boolean context ensures it can now be useful in a C<when()>, notably
+for implementing bistable conditions, like in:
+
+ when (/^=begin/ .. /^=end/) {
+ # do something
+ }
+
+=item defined-or operator
+
+A compound expression involving the defined-or operator, as in
+C<when (expr1 // expr2)>, will be treated as boolean if the first
+expression is boolean. (This just extends the existing rule that applies
+to the regular or operator, as in C<when (expr1 || expr2)>.)
+
+=back
+
+=head2 Smart match changes
+
+Since Perl 5.10.0, Perl's developers have made a number of changes to
+the smart match operator. These, of course, also alter the behaviour
+of the switch statements where smart matching is implicitly used.
+These changes were also made for the 5.10.1 release, and will remain in
+subsequent 5.10 releases.
+
+=head3 Changes to type-based dispatch
+
+The smart match operator C<~~> is no longer commutative. The behaviour of
+a smart match now depends primarily on the type of its right hand
+argument. Moreover, its semantics have been adjusted for greater
+consistency or usefulness in several cases. While the general backwards
+compatibility is maintained, several changes must be noted:
+
+=over 4
+
+=item *
+
+Code references with an empty prototype are no longer treated specially.
+They are passed an argument like the other code references (even if they
+choose to ignore it).
+
+=item *
+
+C<%hash ~~ sub {}> and C<@array ~~ sub {}> now test that the subroutine
+returns a true value for each key of the hash (or element of the
+array), instead of passing the whole hash or array as a reference to
+the subroutine.
+
+=item *
+
+Due to the commutativity breakage, code references are no longer
+treated specially when appearing on the left of the C<~~> operator,
+but like any vulgar scalar.
+
+=item *
+
+C<undef ~~ %hash> is always false (since C<undef> can't be a key in a
+hash). No implicit conversion to C<""> is done (as was the case in perl
+5.10.0).
+
+=item *
+
+C<$scalar ~~ @array> now always distributes the smart match across the
+elements of the array. It's true if one element in @array verifies
+C<$scalar ~~ $element>. This is a generalization of the old behaviour
+that tested whether the array contained the scalar.
+
+=back
+
+The full dispatch table for the smart match operator is given in
+L<perlsyn/"Smart matching in detail">.
+
+=head3 Smart match and overloading
+
+According to the rule of dispatch based on the rightmost argument type,
+when an object overloading C<~~> appears on the right side of the
+operator, the overload routine will always be called (with a 3rd argument
+set to a true value, see L<overload>.) However, when the object will
+appear on the left, the overload routine will be called only when the
+rightmost argument is a simple scalar. This way, distributivity of smart
+match across arrays is not broken, as well as the other behaviours with
+complex types (coderefs, hashes, regexes). Thus, writers of overloading
+routines for smart match mostly need to worry only with comparing
+against a scalar, and possibly with stringification overloading; the
+other common cases will be automatically handled consistently.
+
+C<~~> will now refuse to work on objects that do not overload it (in order
+to avoid relying on the object's underlying structure). (However, if the
+object overloads the stringification or the numification operators, and
+if overload fallback is active, it will be used instead, as usual.)
+
+=head2 Other potentially incompatible changes
+
+=over 4
+
+=item *
+
+The definitions of a number of Unicode properties have changed to match
+those of the current Unicode standard. These are listed above under
+L</Unicode overhaul>. This change may break code that expects the old
+definitions.
+
+=item *
+
+The boolkeys op has moved to the group of hash ops. This breaks binary
+compatibility.
+
+=item *
+
+Filehandles are now always blessed into C<IO::File>.
+
+The previous behaviour was to bless Filehandles into L<FileHandle>
+(an empty proxy class) if it was loaded into memory and otherwise
+to bless them into C<IO::Handle>.
+
+=item *
+
+The semantics of C<use feature :5.10*> have changed slightly.
+See L<"Modules and Pragmata"> for more information.
+
+=item *
+
+Perl's developers now use git, rather than Perforce. This should be
+a purely internal change only relevant to people actively working on
+the core. However, you may see minor difference in perl as a consequence
+of the change. For example in some of details of the output of C<perl
+-V>. See L<perlrepository> for more information.
+
+=item *
+
+As part of the C<Test::Harness> 2.x to 3.x upgrade, the experimental
+C<Test::Harness::Straps> module has been removed.
+See L</"Modules and Pragmata"> for more details.
+
+=item *
+
+As part of the C<ExtUtils::MakeMaker> upgrade, the
+C<ExtUtils::MakeMaker::bytes> and C<ExtUtils::MakeMaker::vmsish> modules
+have been removed from this distribution.
+
+=item *
+
+C<Module::CoreList> no longer contains the C<%:patchlevel> hash.
+
+
+=item *
+
+C<length undef> now returns undef.
+
+=item *
+
+Unsupported private C API functions are now declared "static" to prevent
+leakage to Perl's public API.
+
+=item *
+
+To support the bootstrapping process, F<miniperl> no longer builds with
+UTF-8 support in the regexp engine.
+
+This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.
+Without this there's a bootstrapping problem, as miniperl can't load
+the UTF-8 components of the regexp engine, because they're not yet built.
+
+=item *
+
+F<miniperl>'s @INC is now restricted to just C<-I...>, the split of
+C<$ENV{PERL5LIB}>, and "C<.>"
+
+=item *
+
+A space or a newline is now required after a C<"#line XXX"> directive.
+
+=item *
+
+Tied filehandles now have an additional method EOF which provides the
+EOF type.
+
+=item *
+
+To better match all other flow control statements, C<foreach> may no
+longer be used as an attribute.
+
+=item *
+
+Perl's command-line switch "-P", which was deprecated in version 5.10.0, has
+now been removed.
+
+=back
+
+
+=head1 Deprecations
+
+From time to time, Perl's developers find it necessary to deprecate
+features or modules we've previously shipped as part of the core
+distribution. We are well aware of the pain and frustration that a
+backwards-incompatible change to Perl can cause for developers building
+or maintaining software in Perl. You can be sure that when we deprecate
+a functionality or syntax, it isn't a choice we make lightly. Sometimes,
+we choose to deprecate functionality or syntax because it was found to
+be poorly designed or implemented. Sometimes, this is because they're
+holding back other features or causing performance problems. Sometimes,
+the reasons are more complex. Wherever possible, we try to keep deprecated
+functionality available to developers in its previous form for at least
+one major release. So long as a deprecated feature isn't actively
+disrupting our ability to maintain and extend Perl, we'll try to leave
+it in place as long as possible.
+
+The following items are now deprecated:
+
+=over
+
+=item suidperl
+
+C<suidperl> is no longer part of Perl. It used to provide a mechanism to
+emulate setuid permission bits on systems that don't support it properly.
+
+
+=item Use of C<:=> to mean an empty attribute list
+
+An accident of Perl's parser meant that these constructions were all
+equivalent:
+
+ my $pi := 4;
+ my $pi : = 4;
+ my $pi : = 4;
+
+with the C<:> being treated as the start of an attribute list, which
+ends before the C<=>. As whitespace is not significant here, all are
+parsed as an empty attribute list, hence all the above are equivalent
+to, and better written as
+
+ my $pi = 4;
+
+because no attribute processing is done for an empty list.
+
+As is, this meant that C<:=> cannot be used as a new token, without
+silently changing the meaning of existing code. Hence that particular
+form is now deprecated, and will become a syntax error. If it is
+absolutely necessary to have empty attribute lists (for example,
+because of a code generator) then avoid the warning by adding a space
+before the C<=>.
+
+=item C<< UNIVERSAL->import() >>
+
+The method C<< UNIVERSAL->import() >> is now deprecated. Attempting to
+pass import arguments to a C<use UNIVERSAL> statement will result in a
+deprecation warning.
+
+
+=item Use of "goto" to jump into a construct
+
+Using C<goto> to jump from an outer scope into an inner scope is now
+deprecated. This rare use case was causing problems in the
+implementation of scopes.
+
+=item Custom character names in \N{name} that don't look like names
+
+In C<\N{I<name>}>, I<name> can be just about anything. The standard
+Unicode names have a very limited domain, but a custom name translator
+could create names that are, for example, made up entirely of punctuation
+symbols. It is now deprecated to make names that don't begin with an
+alphabetic character, and aren't alphanumeric or contain other than
+a very few other characters, namely spaces, dashes, parentheses
+and colons. Because of the added meaning of C<\N> (See L</C<\N>
+experimental regex escape>), names that look like curly brace -enclosed
+quantifiers won't work. For example, C<\N{3,4}> now means to match 3 to
+4 non-newlines; before a custom name C<3,4> could have been created.
+
+=item Deprecated Modules
+
+The following modules will be removed from the core distribution in a
+future release, and should be installed from CPAN instead. Distributions
+on CPAN which require these should add them to their prerequisites. The
+core versions of these modules warnings will issue a deprecation warning.
+
+If you ship a packaged version of Perl, either alone or as part of a
+larger system, then you should carefully consider the reprecussions of
+core module deprecations. You may want to consider shipping your default
+build of Perl with packages for some or all deprecated modules which
+install into C<vendor> or C<site> perl library directories. This will
+inhibit the deprecation warnings.
+
+Alternatively, you may want to consider patching F<lib/deprecate.pm>
+to provide deprecation warnings specific to your packaging system
+or distribution of Perl, consistent with how your packaging system
+or distribution manages a staged transition from a release where the
+installation of a single package provides the given functionality, to
+a later release where the system administrator needs to know to install
+multiple packages to get that same functionality.
+
+You can silence these deprecation warnings by installing the modules
+in question from CPAN. To install the latest version of all of them,
+just install C<Task::Deprecations::5_12>.
+
+=over
+
+=item L<Class::ISA>
+
+=item L<Pod::Plainer>
+
+=item L<Shell>
+
+=item L<Switch>
+
+Switch is buggy and should be avoided. You may find Perl's new
+C<given>/C<when> feature a suitable replacement. See L<perlsyn/"Switch
+statements"> for more information.
+
+=back
+
+=item Assignment to $[
+
+=item Use of the attribute :locked on subroutines
+
+=item Use of "locked" with the attributes pragma
+
+=item Use of "unique" with the attributes pragma
+
+=item Perl_pmflag
+
+C<Perl_pmflag> is no longer part of Perl's public API. Calling it now
+generates a deprecation warning, and it will be removed in a future
+release. Although listed as part of the API, it was never documented,
+and only ever used in F<toke.c>, and prior to 5.10, F<regcomp.c>. In
+core, it has been replaced by a static function.
+
+=item Numerous Perl 4-era libraries
+
+F<termcap.pl>, F<tainted.pl>, F<stat.pl>, F<shellwords.pl>, F<pwd.pl>,
+F<open3.pl>, F<open2.pl>, F<newgetopt.pl>, F<look.pl>, F<find.pl>,
+F<finddepth.pl>, F<importenv.pl>, F<hostname.pl>, F<getopts.pl>,
+F<getopt.pl>, F<getcwd.pl>, F<flush.pl>, F<fastcwd.pl>, F<exceptions.pl>,
+F<ctime.pl>, F<complete.pl>, F<cacheout.pl>, F<bigrat.pl>, F<bigint.pl>,
+F<bigfloat.pl>, F<assert.pl>, F<abbrev.pl>, F<dotsh.pl>, and
+F<timelocal.pl> are all now deprecated. Earlier, Perl's developers
+intended to remove these libraries from Perl's core for the 5.14.0 release.
+
+During final testing before the release of 5.12.0, several developers
+discovered current production code using these ancient libraries, some
+inside the Perl core itself. Accordingly, the pumpking granted them
+a stay of execution. They will begin to warn about their deprecation
+in the 5.14.0 release and will be removed in the 5.16.0 release.
+
+
+=back
+
+=head1 Unicode overhaul
+
+Perl's developers have made a concerted effort to update Perl to be in
+sync with the latest Unicode standard. Changes for this include:
+
+Perl can now handle every Unicode character property. New documentation,
+L<perluniprops>, lists all available non-Unihan character properties. By
+default, perl does not expose Unihan, deprecated or Unicode-internal
+properties. See below for more details on these; there is also a section
+in the pod listing them, and explaining why they are not exposed.
+
+Perl now fully supports the Unicode compound-style of using C<=>
+and C<:> in writing regular expressions: C<\p{property=value}> and
+C<\p{property:value}> (both of which mean the same thing).
+
+Perl now fully supports the Unicode loose matching rules for text between
+the braces in C<\p{...}> constructs. In addition, Perl allows underscores
+between digits of numbers.
+
+Perl now accepts all the Unicode-defined synonyms for properties and
+property values.
+
+C<qr/\X/>, which matches a Unicode logical character, has
+been expanded to work better with various Asian languages. It
+now is defined as an I<extended grapheme cluster>. (See
+L<http://www.unicode.org/reports/tr29/>). Anything matched previously
+and that made sense will continue to be accepted. Additionally:
+
+=over
+
+=item *
+
+C<\X> will not break apart a C<S<CR LF>> sequence.
+
+=item *
+
+C<\X> will now match a sequence which includes the C<ZWJ> and C<ZWNJ>
+characters.
+
+=item *
+
+C<\X> will now always match at least one character, including an initial
+mark. Marks generally come after a base character, but it is possible in
+Unicode to have them in isolation, and C<\X> will now handle that case,
+for example at the beginning of a line, or after a C<ZWSP>. And this is
+the part where C<\X> doesn't match the things that it used to that don't
+make sense. Formerly, for example, you could have the nonsensical case
+of an accented LF.
+
+=item *
+
+C<\X> will now match a (Korean) Hangul syllable sequence, and the Thai
+and Lao exception cases.
+
+=back
+
+Otherwise, this change should be transparent for the non-affected
+languages.
+
+C<\p{...}> matches using the Canonical_Combining_Class property were
+completely broken in previous releases of Perl. They should now work
+correctly.
+
+Before Perl 5.12, the Unicode C<Decomposition_Type=Compat> property
+and a Perl extension had the same name, which led to neither matching
+all the correct values (with more than 100 mistakes in one, and several
+thousand in the other). The Perl extension has now been renamed to be
+C<Decomposition_Type=Noncanonical> (short: C<dt=noncanon>). It has the
+same meaning as was previously intended, namely the union of all the
+non-canonical Decomposition types, with Unicode C<Compat> being just
+one of those.
+
+C<\p{Decomposition_Type=Canonical}> now includes the Hangul syllables.
+
+C<\p{Uppercase}> and C<\p{Lowercase}> now work as the Unicode standard
+says they should. This means they each match a few more characters than
+they used to.
+
+C<\p{Cntrl}> now matches the same characters as C<\p{Control}>. This
+means it no longer will match Private Use (gc=co), Surrogates (gc=cs),
+nor Format (gc=cf) code points. The Format code points represent the
+biggest possible problem. All but 36 of them are either officially
+deprecated or strongly discouraged from being used. Of those 36, likely
+the most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,
+WJ, and similar characters, plus bidirectional controls.
+
+C<\p{Alpha}> now matches the same characters as C<\p{Alphabetic}>. Before
+5.12, Perl's definition definition included a number of things that aren't
+really alpha (all marks) while omitting many that were. The definitions
+of C<\p{Alnum}> and C<\p{Word}> depend on Alpha's definition and have
+changed accordingly.
+
+C<\p{Word}> no longer incorrectly matches non-word characters such
+as fractions.
+
+C<\p{Print}> no longer matches the line control characters: Tab, LF,
+CR, FF, VT, and NEL. This brings it in line with standards and the
+documentation.
+
+C<\p{XDigit}> now matches the same characters as C<\p{Hex_Digit}>. This
+means that in addition to the characters it currently matches,
+C<[A-Fa-f0-9]>, it will also match the 22 fullwidth equivalents, for
+example U+FF10: FULLWIDTH DIGIT ZERO.
+
+The Numeric type property has been extended to include the Unihan
+characters.
+
+There is a new Perl extension, the 'Present_In', or simply 'In',
+property. This is an extension of the Unicode Age property, but
+C<\p{In=5.0}> matches any code point whose usage has been determined
+I<as of> Unicode version 5.0. The C<\p{Age=5.0}> only matches code points
+added in I<precisely> version 5.0.
+
+A number of properties now have the correct values for unassigned
+code points. The affected properties are Bidi_Class, East_Asian_Width,
+Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,
+and Line_Break.
+
+The Default_Ignorable_Code_Point, ID_Continue, and ID_Start properties
+are now up to date with current Unicode definitions.
+
+Earlier versions of Perl erroneously exposed certain properties that
+are supposed to be Unicode internal-only. Use of these in regular
+expressions will now generate, if enabled, a deprecation warning message.
+The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,
+Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,
+Other_Math, and Other_Uppercase.
+
+It is now possible to change which Unicode properties Perl understands
+on a per-installation basis. As mentioned above, certain properties
+are turned off by default. These include all the Unihan properties
+(which should be accessible via the CPAN module Unicode::Unihan) and any
+deprecated or Unicode internal-only property that Perl has never exposed.
+
+The generated files in the C<lib/unicore/To> directory are now more
+clearly marked as being stable, directly usable by applications. New hash
+entries in them give the format of the normal entries, which allows for
+easier machine parsing. Perl can generate files in this directory for
+any property, though most are suppressed. You can find instructions
+for changing which are written in L<perluniprops>.
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item C<autodie>
+
+C<autodie> is a new lexically-scoped alternative for the C<Fatal> module.
+The bundled version is 2.06_01. Note that in this release, using a string
+eval when C<autodie> is in effect can cause the autodie behaviour to leak
+into the surrounding scope. See L<autodie/"BUGS"> for more details.
+
+Version 2.06_01 has been added to the Perl core.
+
+=item C<Compress::Raw::Bzip2>
+
+Version 2.024 has been added to the Perl core.
+
+=item C<overloading>
+
+C<overloading> allows you to lexically disable or enable overloading
+for some or all operations.
+
+Version 0.001 has been added to the Perl core.
+
+=item C<parent>
+
+C<parent> establishes an ISA relationship with base classes at compile
+time. It provides the key feature of C<base> without further unwanted
+behaviors.
+
+Version 0.223 has been added to the Perl core.
+
+=item C<Parse::CPAN::Meta>
+
+Version 1.40 has been added to the Perl core.
+
+=item C<VMS::DCLsym>
+
+Version 1.03 has been added to the Perl core.
+
+=item C<VMS::Stdio>
+
+Version 2.4 has been added to the Perl core.
+
+=item C<XS::APItest::KeywordRPN>
+
+Version 0.003 has been added to the Perl core.
+
+=back
+
+=head2 Updated Pragmata
+
+=over 4
+
+=item C<base>
+
+Upgraded from version 2.13 to 2.15.
+
+=item C<bignum>
+
+Upgraded from version 0.22 to 0.23.
+
+=item C<charnames>
+
+C<charnames> now contains the Unicode F<NameAliases.txt> database file.
+This has the effect of adding some extra C<\N> character names that
+formerly wouldn't have been recognised; for example, C<"\N{LATIN CAPITAL
+LETTER GHA}">.
+
+Upgraded from version 1.06 to 1.07.
+
+=item C<constant>
+
+Upgraded from version 1.13 to 1.20.
+
+=item C<diagnostics>
+
+C<diagnostics> now supports %.0f formatting internally.
+
+C<diagnostics> no longer suppresses C<Use of uninitialized value in range
+(or flip)> warnings. [perl #71204]
+
+Upgraded from version 1.17 to 1.19.
+
+=item C<feature>
+
+In C<feature>, the meaning of the C<:5.10> and C<:5.10.X> feature
+bundles has changed slightly. The last component, if any (i.e. C<X>) is
+simply ignored. This is predicated on the assumption that new features
+will not, in general, be added to maintenance releases. So C<:5.10>
+and C<:5.10.X> have identical effect. This is a change to the behaviour
+documented for 5.10.0.
+
+C<feature> now includes the C<unicode_strings> feature:
+
+ use feature "unicode_strings";
+
+This pragma turns on Unicode semantics for the case-changing operations
+(C<uc>, C<lc>, C<ucfirst>, C<lcfirst>) on strings that don't have the
+internal UTF-8 flag set, but that contain single-byte characters between
+128 and 255.
+
+Upgraded from version 1.11 to 1.16.
+
+=item C<less>
+
+C<less> now includes the C<stash_name> method to allow subclasses of
+C<less> to pick where in %^H to store their stash.
+
+Upgraded from version 0.02 to 0.03.
+
+=item C<lib>
+
+Upgraded from version 0.5565 to 0.62.
+
+=item C<mro>
+
+C<mro> is now implemented as an XS extension. The documented interface has
+not changed. Code relying on the implementation detail that some C<mro::>
+methods happened to be available at all times gets to "keep both pieces".
+
+Upgraded from version 1.00 to 1.02.
+
+=item C<overload>
+
+C<overload> now allow overloading of 'qr'.
+
+Upgraded from version 1.06 to 1.10.
+
+=item C<threads>
+
+Upgraded from version 1.67 to 1.75.
+
+=item C<threads::shared>
+
+Upgraded from version 1.14 to 1.32.
+
+=item C<version>
+
+C<version> now has support for L</Version number formats> as described
+earlier in this document and in its own documentation.
+
+Upgraded from version 0.74 to 0.82.
+
+=item C<warnings>
+
+C<warnings> has a new C<warnings::fatal_enabled()> function. It also
+includes a new C<illegalproto> warning category. See also L</New or
+Changed Diagnostics> for this change.
+
+Upgraded from version 1.06 to 1.09.
+
+=back
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Archive::Extract>
+
+Upgraded from version 0.24 to 0.38.
+
+=item C<Archive::Tar>
+
+Upgraded from version 1.38 to 1.54.
+
+=item C<Attribute::Handlers>
+
+Upgraded from version 0.79 to 0.87.
+
+=item C<AutoLoader>
+
+Upgraded from version 5.63 to 5.70.
+
+=item C<B::Concise>
+
+Upgraded from version 0.74 to 0.78.
+
+=item C<B::Debug>
+
+Upgraded from version 1.05 to 1.12.
+
+=item C<B::Deparse>
+
+Upgraded from version 0.83 to 0.96.
+
+=item C<B::Lint>
+
+Upgraded from version 1.09 to 1.11_01.
+
+=item C<CGI>
+
+Upgraded from version 3.29 to 3.48.
+
+=item C<Class::ISA>
+
+Upgraded from version 0.33 to 0.36.
+
+NOTE: C<Class::ISA> is deprecated and may be removed from a future
+version of Perl.
+
+=item C<Compress::Raw::Zlib>
+
+Upgraded from version 2.008 to 2.024.
+
+=item C<CPAN>
+
+Upgraded from version 1.9205 to 1.94_56.
+
+=item C<CPANPLUS>
+
+Upgraded from version 0.84 to 0.90.
+
+=item C<CPANPLUS::Dist::Build>
+
+Upgraded from version 0.06_02 to 0.46.
+
+=item C<Data::Dumper>
+
+Upgraded from version 2.121_14 to 2.125.
+
+=item C<DB_File>
+
+Upgraded from version 1.816_1 to 1.820.
+
+=item C<Devel::PPPort>
+
+Upgraded from version 3.13 to 3.19.
+
+=item C<Digest>
+
+Upgraded from version 1.15 to 1.16.
+
+=item C<Digest::MD5>
+
+Upgraded from version 2.36_01 to 2.39.
+
+=item C<Digest::SHA>
+
+Upgraded from version 5.45 to 5.47.
+
+=item C<Encode>
+
+Upgraded from version 2.23 to 2.39.
+
+=item C<Exporter>
+
+Upgraded from version 5.62 to 5.64_01.
+
+=item C<ExtUtils::CBuilder>
+
+Upgraded from version 0.21 to 0.27.
+
+=item C<ExtUtils::Command>
+
+Upgraded from version 1.13 to 1.16.
+
+=item C<ExtUtils::Constant>
+
+Upgraded from version 0.2 to 0.22.
+
+=item C<ExtUtils::Install>
+
+Upgraded from version 1.44 to 1.55.
+
+=item C<ExtUtils::MakeMaker>
+
+Upgraded from version 6.42 to 6.56.
+
+=item C<ExtUtils::Manifest>
+
+Upgraded from version 1.51_01 to 1.57.
+
+=item C<ExtUtils::ParseXS>
+
+Upgraded from version 2.18_02 to 2.21.
+
+=item C<File::Fetch>
+
+Upgraded from version 0.14 to 0.24.
+
+=item C<File::Path>
+
+Upgraded from version 2.04 to 2.08_01.
+
+=item C<File::Temp>
+
+Upgraded from version 0.18 to 0.22.
+
+=item C<Filter::Simple>
+
+Upgraded from version 0.82 to 0.84.
+
+=item C<Filter::Util::Call>
+
+Upgraded from version 1.07 to 1.08.
+
+=item C<Getopt::Long>
+
+Upgraded from version 2.37 to 2.38.
+
+=item C<IO>
+
+Upgraded from version 1.23_01 to 1.25_02.
+
+=item C<IO::Zlib>
+
+Upgraded from version 1.07 to 1.10.
+
+=item C<IPC::Cmd>
+
+Upgraded from version 0.40_1 to 0.54.
+
+=item C<IPC::SysV>
+
+Upgraded from version 1.05 to 2.01.
+
+=item C<Locale::Maketext>
+
+Upgraded from version 1.12 to 1.14.
+
+=item C<Locale::Maketext::Simple>
+
+Upgraded from version 0.18 to 0.21.
+
+=item C<Log::Message>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<Log::Message::Simple>
+
+Upgraded from version 0.04 to 0.06.
+
+=item C<Math::BigInt>
+
+Upgraded from version 1.88 to 1.89_01.
+
+=item C<Math::BigInt::FastCalc>
+
+Upgraded from version 0.16 to 0.19.
+
+=item C<Math::BigRat>
+
+Upgraded from version 0.21 to 0.24.
+
+=item C<Math::Complex>
+
+Upgraded from version 1.37 to 1.56.
+
+=item C<Memoize>
+
+Upgraded from version 1.01_02 to 1.01_03.
+
+=item C<MIME::Base64>
+
+Upgraded from version 3.07_01 to 3.08.
+
+=item C<Module::Build>
+
+Upgraded from version 0.2808_01 to 0.3603.
+
+=item C<Module::CoreList>
+
+Upgraded from version 2.12 to 2.29.
+
+=item C<Module::Load>
+
+Upgraded from version 0.12 to 0.16.
+
+=item C<Module::Load::Conditional>
+
+Upgraded from version 0.22 to 0.34.
+
+=item C<Module::Loaded>
+
+Upgraded from version 0.01 to 0.06.
+
+=item C<Module::Pluggable>
+
+Upgraded from version 3.6 to 3.9.
+
+=item C<Net::Ping>
+
+Upgraded from version 2.33 to 2.36.
+
+=item C<NEXT>
+
+Upgraded from version 0.60_01 to 0.64.
+
+=item C<Object::Accessor>
+
+Upgraded from version 0.32 to 0.36.
+
+=item C<Package::Constants>
+
+Upgraded from version 0.01 to 0.02.
+
+=item C<PerlIO>
+
+Upgraded from version 1.04 to 1.06.
+
+=item C<Pod::Parser>
+
+Upgraded from version 1.35 to 1.37.
+
+=item C<Pod::Perldoc>
+
+Upgraded from version 3.14_02 to 3.15_02.
+
+=item C<Pod::Plainer>
+
+Upgraded from version 0.01 to 1.02.
+
+NOTE: C<Pod::Plainer> is deprecated and may be removed from a future
+version of Perl.
+
+=item C<Pod::Simple>
+
+Upgraded from version 3.05 to 3.13.
+
+=item C<Safe>
+
+Upgraded from version 2.12 to 2.22.
+
+=item C<SelfLoader>
+
+Upgraded from version 1.11 to 1.17.
+
+=item C<Storable>
+
+Upgraded from version 2.18 to 2.22.
+
+=item C<Switch>
+
+Upgraded from version 2.13 to 2.16.
+
+NOTE: C<Switch> is deprecated and may be removed from a future version
+of Perl.
+
+=item C<Sys::Syslog>
+
+Upgraded from version 0.22 to 0.27.
+
+=item C<Term::ANSIColor>
+
+Upgraded from version 1.12 to 2.02.
+
+=item C<Term::UI>
+
+Upgraded from version 0.18 to 0.20.
+
+=item C<Test>
+
+Upgraded from version 1.25 to 1.25_02.
+
+=item C<Test::Harness>
+
+Upgraded from version 2.64 to 3.17.
+
+=item C<Test::Simple>
+
+Upgraded from version 0.72 to 0.94.
+
+=item C<Text::Balanced>
+
+Upgraded from version 2.0.0 to 2.02.
+
+=item C<Text::ParseWords>
+
+Upgraded from version 3.26 to 3.27.
+
+=item C<Text::Soundex>
+
+Upgraded from version 3.03 to 3.03_01.
+
+=item C<Thread::Queue>
+
+Upgraded from version 2.00 to 2.11.
+
+=item C<Thread::Semaphore>
+
+Upgraded from version 2.01 to 2.09.
+
+=item C<Tie::RefHash>
+
+Upgraded from version 1.37 to 1.38.
+
+=item C<Time::HiRes>
+
+Upgraded from version 1.9711 to 1.9719.
+
+=item C<Time::Local>
+
+Upgraded from version 1.18 to 1.1901_01.
+
+=item C<Time::Piece>
+
+Upgraded from version 1.12 to 1.15.
+
+=item C<Unicode::Collate>
+
+Upgraded from version 0.52 to 0.52_01.
+
+=item C<Unicode::Normalize>
+
+Upgraded from version 1.02 to 1.03.
+
+=item C<Win32>
+
+Upgraded from version 0.34 to 0.39.
+
+=item C<Win32API::File>
+
+Upgraded from version 0.1001_01 to 0.1101.
+
+=item C<XSLoader>
+
+Upgraded from version 0.08 to 0.10.
+
+=back
+
+=head2 Removed Modules and Pragmata
+
+=over 4
+
+=item C<attrs>
+
+Removed from the Perl core. Prior version was 1.02.
+
+=item C<CPAN::API::HOWTO>
+
+Removed from the Perl core. Prior version was 'undef'.
+
+=item C<CPAN::DeferedCode>
+
+Removed from the Perl core. Prior version was 5.50.
+
+=item C<CPANPLUS::inc>
+
+Removed from the Perl core. Prior version was 'undef'.
+
+=item C<DCLsym>
+
+Removed from the Perl core. Prior version was 1.03.
+
+=item C<ExtUtils::MakeMaker::bytes>
+
+Removed from the Perl core. Prior version was 6.42.
+
+=item C<ExtUtils::MakeMaker::vmsish>
+
+Removed from the Perl core. Prior version was 6.42.
+
+=item C<Stdio>
+
+Removed from the Perl core. Prior version was 2.3.
+
+=item C<Test::Harness::Assert>
+
+Removed from the Perl core. Prior version was 0.02.
+
+=item C<Test::Harness::Iterator>
+
+Removed from the Perl core. Prior version was 0.02.
+
+=item C<Test::Harness::Point>
+
+Removed from the Perl core. Prior version was 0.01.
+
+=item C<Test::Harness::Results>
+
+Removed from the Perl core. Prior version was 0.01.
+
+=item C<Test::Harness::Straps>
+
+Removed from the Perl core. Prior version was 0.26_01.
+
+=item C<Test::Harness::Util>
+
+Removed from the Perl core. Prior version was 0.01.
+
+=item C<XSSymSet>
+
+Removed from the Perl core. Prior version was 1.1.
+
+=back
+
+=head2 Deprecated Modules and Pragmata
+
+See L</Deprecated Modules> above.
+
+
+=head1 Documentation
+
+=head2 New Documentation
+
+=over 4
+
+=item *
+
+L<perlhaiku> contains instructions on how to build perl for the Haiku
+platform.
+
+=item *
+
+L<perlmroapi> describes the new interface for pluggable Method Resolution
+Orders.
+
+=item *
+
+L<perlperf>, by Richard Foley, provides an introduction to the use of
+performance and optimization techniques which can be used with particular
+reference to perl programs.
+
+=item *
+
+L<perlrepository> describes how to access the perl source using the I<git>
+version control system.
+
+=item *
+
+L<perlpolicy> extends the "Social contract about contributed modules" into
+the beginnings of a document on Perl porting policies.
+
+=back
+
+=head2 Changes to Existing Documentation
+
+
+=over
+
+
+=item *
+
+The various large F<Changes*> files (which listed every change made
+to perl over the last 18 years) have been removed, and replaced by a
+small file, also called F<Changes>, which just explains how that same
+information may be extracted from the git version control system.
+
+=item *
+
+F<Porting/patching.pod> has been deleted, as it mainly described
+interacting with the old Perforce-based repository, which is now obsolete.
+Information still relevant has been moved to L<perlrepository>.
+
+
+=item *
+
+The syntax C<unless (EXPR) BLOCK else BLOCK> is now documented as valid,
+as is the syntax C<unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else
+BLOCK>, although actually using the latter may not be the best idea for
+the readability of your source code.
+
+
+=item *
+
+Documented -X overloading.
+
+=item *
+
+Documented that C<when()> treats specially most of the filetest operators
+
+=item *
+
+Documented C<when> as a syntax modifier.
+
+=item *
+
+Eliminated "Old Perl threads tutorial", which described 5005 threads.
+
+F<pod/perlthrtut.pod> is the same material reworked for ithreads.
+
+=item *
+
+Correct previous documentation: v-strings are not deprecated
+
+With version objects, we need them to use MODULE VERSION syntax. This
+patch removes the deprecation notice.
+
+=item *
+
+Security contact information is now part of L<perlsec>.
+
+=item *
+
+A significant fraction of the core documentation has been updated to
+clarify the behavior of Perl's Unicode handling.
+
+Much of the remaining core documentation has been reviewed and edited
+for clarity, consistent use of language, and to fix the spelling of Tom
+Christiansen's name.
+
+=item *
+
+The Pod specification (L<perlpodspec>) has been updated to bring the
+specification in line with modern usage already supported by most Pod
+systems. A parameter string may now follow the format name in a
+"begin/end" region. Links to URIs with a text description are now
+allowed. The usage of C<LE<lt>"section"E<gt>> has been marked as
+deprecated.
+
+=item *
+
+L<if.pm|if> has been documented in L<perlfunc/use> as a means to get
+conditional loading of modules despite the implicit BEGIN block around
+C<use>.
+
+=item *
+
+The documentation for C<$1> in perlvar.pod has been clarified.
+
+=item *
+
+C<\N{U+I<wide hex char>}> is now documented.
+
+=back
+
+=head1 Selected Performance Enhancements
+
+=over 4
+
+=item *
+
+A new internal cache means that C<isa()> will often be faster.
+
+=item *
+
+The implementation of C<C3> Method Resolution Order has been
+optimised - linearisation for classes with single inheritance is 40%
+faster. Performance for multiple inheritance is unchanged.
+
+=item *
+
+Under C<use locale>, the locale-relevant information is now cached on
+read-only values, such as the list returned by C<keys %hash>. This makes
+operations such as C<sort keys %hash> in the scope of C<use locale>
+much faster.
+
+=item *
+
+Empty C<DESTROY> methods are no longer called.
+
+=item *
+
+C<Perl_sv_utf8_upgrade()> is now faster.
+
+=item *
+
+C<keys> on empty hash is now faster.
+
+=item *
+
+C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>.
+
+=item *
+
+The string repetition operator (C<$str x $num>) is now several times
+faster when C<$str> has length one or C<$num> is large.
+
+=item *
+
+Reversing an array to itself (as in C<@a = reverse @a>) in void context
+now happens in-place and is several orders of magnitude faster than
+it used to be. It will also preserve non-existent elements whenever
+possible, i.e. for non magical arrays or tied arrays with C<EXISTS>
+and C<DELETE> methods.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=over 4
+
+=item *
+
+L<perlapi>, L<perlintern>, L<perlmodlib> and L<perltoc> are now all
+generated at build time, rather than being shipped as part of the release.
+
+=item *
+
+If C<vendorlib> and C<vendorarch> are the same, then they are only added
+to C<@INC> once.
+
+=item *
+
+C<$Config{usedevel}> and the C-level C<PERL_USE_DEVEL> are now defined if
+perl is built with C<-Dusedevel>.
+
+=item *
+
+F<Configure> will enable use of C<-fstack-protector>, to provide protection
+against stack-smashing attacks, if the compiler supports it.
+
+=item *
+
+F<Configure> will now determine the correct prototypes for re-entrant
+functions and for C<gconvert> if you are using a C++ compiler rather
+than a C compiler.
+
+=item *
+
+On Unix, if you build from a tree containing a git repository, the
+configuration process will note the commit hash you have checked out, for
+display in the output of C<perl -v> and C<perl -V>. Unpushed local commits
+are automatically added to the list of local patches displayed by
+C<perl -V>.
+
+=item *
+
+Perl now supports SystemTap's C<dtrace> compatibility layer and an
+issue with linking C<miniperl> has been fixed in the process.
+
+=item *
+
+perldoc now uses C<less -R> instead of C<less> for improved behaviour
+in the face of C<groff>'s new usage of ANSI escape codes.
+
+=item *
+
+
+C<perl -V> now reports use of the compile-time options C<USE_PERL_ATOF> and
+C<USE_ATTRIBUTES_FOR_PERLIO>.
+
+=item *
+
+As part of the flattening of F<ext>, all extensions on all platforms are
+built by F<make_ext.pl>. This replaces the Unix-specific
+F<ext/util/make_ext>, VMS-specific F<make_ext.com> and Win32-specific
+F<win32/buildext.pl>.
+
+=back
+
+=head1 Internal Changes
+
+Each release of Perl sees numerous internal changes which shouldn't
+affect day to day usage but may still be notable for developers working
+with Perl's source code.
+
+=over
+
+=item *
+
+The J.R.R. Tolkien quotes at the head of C source file have been checked
+and proper citations added, thanks to a patch from Tom Christiansen.
+
+=item *
+
+The internal structure of the dual-life modules traditionally found in
+the F<lib/> and F<ext/> directories in the perl source has changed
+significantly. Where possible, dual-lifed modules have been extracted
+from F<lib/> and F<ext/>.
+
+Dual-lifed modules maintained by Perl's developers as part of the Perl
+core now live in F<dist/>. Dual-lifed modules maintained primarily on
+CPAN now live in F<cpan/>. When reporting a bug in a module located
+under F<cpan/>, please send your bug report directly to the module's
+bug tracker or author, rather than Perl's bug tracker.
+
+=item *
+
+C<\N{...}> now compiles better, always forces UTF-8 internal representation
+
+Perl's developers have fixed several problems with the recognition of
+C<\N{...}> constructs. As part of this, perl will store any scalar
+or regex containing C<\N{I<name>}> or C<\N{U+I<wide hex char>}> in its
+definition in UTF-8 format. (This was true previously for all occurences
+of C<\N{I<name>}> that did not use a custom translator, but now it's
+always true.)
+
+=item *
+
+Perl_magic_setmglob now knows about globs, fixing RT #71254.
+
+=item *
+
+C<SVt_RV> no longer exists. RVs are now stored in IVs.
+
+=item *
+
+C<Perl_vcroak()> now accepts a null first argument. In addition, a full
+audit was made of the "not NULL" compiler annotations, and those for
+several other internal functions were corrected.
+
+=item *
+
+New macros C<dSAVEDERRNO>, C<dSAVE_ERRNO>, C<SAVE_ERRNO>, C<RESTORE_ERRNO>
+have been added to formalise the temporary saving of the C<errno>
+variable.
+
+=item *
+
+The function C<Perl_sv_insert_flags> has been added to augment
+C<Perl_sv_insert>.
+
+=item *
+
+The function C<Perl_newSV_type(type)> has been added, equivalent to
+C<Perl_newSV()> followed by C<Perl_sv_upgrade(type)>.
+
+=item *
+
+The function C<Perl_newSVpvn_flags()> has been added, equivalent to
+C<Perl_newSVpvn()> and then performing the action relevant to the flag.
+
+Two flag bits are currently supported.
+
+=over 4
+
+=item *
+
+C<SVf_UTF8> will call C<SvUTF8_on()> for you. (Note that this does
+not convert an sequence of ISO 8859-1 characters to UTF-8). A wrapper,
+C<newSVpvn_utf8()> is available for this.
+
+=item *
+
+C<SVs_TEMP> now calls C<Perl_sv_2mortal()> on the new SV.
+
+=back
+
+There is also a wrapper that takes constant strings, C<newSVpvs_flags()>.
+
+=item *
+
+The function C<Perl_croak_xs_usage> has been added as a wrapper to
+C<Perl_croak>.
+
+=item *
+
+Perl now exports the functions C<PerlIO_find_layer> and C<PerlIO_list_alloc>.
+
+=item *
+
+C<PL_na> has been exterminated from the core code, replaced by local
+STRLEN temporaries, or C<*_nolen()> calls. Either approach is faster than
+C<PL_na>, which is a pointer dereference into the interpreter structure
+under ithreads, and a global variable otherwise.
+
+=item *
+
+C<Perl_mg_free()> used to leave freed memory accessible via C<SvMAGIC()>
+on the scalar. It now updates the linked list to remove each piece of
+magic as it is freed.
+
+=item *
+
+Under ithreads, the regex in C<PL_reg_curpm> is now reference
+counted. This eliminates a lot of hackish workarounds to cope with it
+not being reference counted.
+
+=item *
+
+C<Perl_mg_magical()> would sometimes incorrectly turn on C<SvRMAGICAL()>.
+This has been fixed.
+
+=item *
+
+The I<public> IV and NV flags are now not set if the string value has
+trailing "garbage". This behaviour is consistent with not setting the
+public IV or NV flags if the value is out of range for the type.
+
+=item *
+
+Uses of C<Nullav>, C<Nullcv>, C<Nullhv>, C<Nullop>, C<Nullsv> etc have
+been replaced by C<NULL> in the core code, and non-dual-life modules,
+as C<NULL> is clearer to those unfamiliar with the core code.
+
+=item *
+
+A macro C<MUTABLE_PTR(p)> has been added, which on (non-pedantic) gcc will
+not cast away C<const>, returning a C<void *>. Macros C<MUTABLE_SV(av)>,
+C<MUTABLE_SV(cv)> etc build on this, casting to C<AV *> etc without
+casting away C<const>. This allows proper compile-time auditing of
+C<const> correctness in the core, and helped picked up some errors
+(now fixed).
+
+=item *
+
+Macros C<mPUSHs()> and C<mXPUSHs()> have been added, for pushing SVs on the
+stack and mortalizing them.
+
+=item *
+
+Use of the private structure C<mro_meta> has changed slightly. Nothing
+outside the core should be accessing this directly anyway.
+
+=item *
+
+A new tool, F<Porting/expand-macro.pl> has been added, that allows you
+to view how a C preprocessor macro would be expanded when compiled.
+This is handy when trying to decode the macro hell that is the perl
+guts.
+
+=back
+
+=head1 Testing
+
+=head2 Testing improvements
+
+=over 4
+
+=item Parallel tests
+
+The core distribution can now run its regression tests in parallel on
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
+your environment to the number of tests to run in parallel, and run
+C<make test_harness>. On a Bourne-like shell, this can be done as
+
+ TEST_JOBS=3 make test_harness # Run 3 tests in parallel
+
+An environment variable is used, rather than parallel make itself, because
+L<TAP::Harness> needs to be able to schedule individual non-conflicting test
+scripts itself, and there is no standard interface to C<make> utilities to
+interact with their job schedulers.
+
+Note that currently some test scripts may fail when run in parallel (most
+notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
+again sequentially and see if the failures go away.
+
+=item Test harness flexibility
+
+It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
+
+=item Test watchdog
+
+Several tests that have the potential to hang forever if they fail now
+incorporate a "watchdog" functionality that will kill them after a timeout,
+which helps ensure that C<make test> and C<make test_harness> run to
+completion automatically.
+
+
+=back
+
+=head2 New Tests
+
+Perl's developers have added a number of new tests to the core.
+In addition to the items listed below, many modules updated from CPAN
+incorporate new tests.
+
+=over 4
+
+=item *
+
+Significant cleanups to core tests to ensure that language and
+interpreter features are not used before they're tested.
+
+=item *
+
+C<make test_porting> now runs a number of important pre-commit checks
+which might be of use to anyone working on the Perl core.
+
+=item *
+
+F<t/porting/podcheck.t> automatically checks the well-formedness of
+POD found in all .pl, .pm and .pod files in the F<MANIFEST>, other than in
+dual-lifed modules which are primarily maintained outside the Perl core.
+
+=item *
+
+F<t/porting/manifest.t> now tests that all files listed in MANIFEST
+are present.
+
+=item *
+
+F<t/op/while_readdir.t> tests that a bare readdir in while loop sets $_.
+
+=item *
+
+F<t/comp/retainedlines.t> checks that the debugger can retain source
+lines from C<eval>.
+
+=item *
+
+F<t/io/perlio_fail.t> checks that bad layers fail.
+
+=item *
+
+F<t/io/perlio_leaks.t> checks that PerlIO layers are not leaking.
+
+=item *
+
+F<t/io/perlio_open.t> checks that certain special forms of open work.
+
+=item *
+
+F<t/io/perlio.t> includes general PerlIO tests.
+
+=item *
+
+F<t/io/pvbm.t> checks that there is no unexpected interaction between
+the internal types C<PVBM> and C<PVGV>.
+
+=item *
+
+F<t/mro/package_aliases.t> checks that mro works properly in the presence
+of aliased packages.
+
+=item *
+
+F<t/op/dbm.t> tests C<dbmopen> and C<dbmclose>.
+
+=item *
+
+F<t/op/index_thr.t> tests the interaction of C<index> and threads.
+
+=item *
+
+F<t/op/pat_thr.t> tests the interaction of esoteric patterns and threads.
+
+=item *
+
+F<t/op/qr_gc.t> tests that C<qr> doesn't leak.
+
+=item *
+
+F<t/op/reg_email_thr.t> tests the interaction of regex recursion and threads.
+
+=item *
+
+F<t/op/regexp_qr_embed_thr.t> tests the interaction of patterns with
+embedded C<qr//> and threads.
+
+=item *
+
+F<t/op/regexp_unicode_prop.t> tests Unicode properties in regular
+expressions.
+
+=item *
+
+F<t/op/regexp_unicode_prop_thr.t> tests the interaction of Unicode
+properties and threads.
+
+=item *
+
+F<t/op/reg_nc_tie.t> tests the tied methods of C<Tie::Hash::NamedCapture>.
+
+=item *
+
+F<t/op/reg_posixcc.t> checks that POSIX character classes behave
+consistently.
+
+=item *
+
+F<t/op/re.t> checks that exportable C<re> functions in F<universal.c> work.
+
+=item *
+
+F<t/op/setpgrpstack.t> checks that C<setpgrp> works.
+
+=item *
+
+F<t/op/substr_thr.t> tests the interaction of C<substr> and threads.
+
+=item *
+
+F<t/op/upgrade.t> checks that upgrading and assigning scalars works.
+
+=item *
+
+F<t/uni/lex_utf8.t> checks that Unicode in the lexer works.
+
+=item *
+
+F<t/uni/tie.t> checks that Unicode and C<tie> work.
+
+=item *
+
+F<t/comp/final_line_num.t> tests whether line numbers are correct at EOF
+
+=item *
+
+F<t/comp/form_scope.t> tests format scoping.
+
+=item *
+
+F<t/comp/line_debug.t> tests whether C<< @{"_<$file"} >> works.
+
+=item *
+
+F<t/op/filetest_t.t> tests if -t file test works.
+
+=item *
+
+F<t/op/qr.t> tests C<qr>.
+
+=item *
+
+F<t/op/utf8cache.t> tests malfunctions of the utf8 cache.
+
+=item *
+
+F<t/re/uniprops.t> test unicodes C<\p{}> regex constructs.
+
+=item *
+
+F<t/op/filehandle.t> tests some suitably portable filetest operators
+to check that they work as expected, particularly in the light of some
+internal changes made in how filehandles are blessed.
+
+=item *
+
+F<t/op/time_loop.t> tests that unix times greater than C<2**63>, which
+can now be handed to C<gmtime> and C<localtime>, do not cause an internal
+overflow or an excessively long loop.
+
+=back
+
+
+=head1 New or Changed Diagnostics
+
+=head2 New Diagnostics
+
+=over
+
+=item *
+
+SV allocation tracing has been added to the diagnostics enabled by C<-Dm>.
+The tracing can alternatively output via the C<PERL_MEM_LOG> mechanism, if
+that was enabled when the F<perl> binary was compiled.
+
+=item *
+
+Smartmatch resolution tracing has been added as a new diagnostic. Use
+C<-DM> to enable it.
+
+=item *
+
+A new debugging flag C<-DB> now dumps subroutine definitions, leaving
+C<-Dx> for its original purpose of dumping syntax trees.
+
+=item *
+
+Perl 5.12 provides a number of new diagnostic messages to help you write
+better code. See L<perldiag> for details of these new messages.
+
+=over 4
+
+=item *
+
+C<Bad plugin affecting keyword '%s'>
+
+=item *
+
+C<gmtime(%.0f) too large>
+
+=item *
+
+C<Lexing code attempted to stuff non-Latin-1 character into Latin-1 input>
+
+=item *
+
+C<Lexing code internal error (%s)>
+
+=item *
+
+C<localtime(%.0f) too large>
+
+=item *
+
+C<Overloaded dereference did not return a reference>
+
+=item *
+
+C<Overloaded qr did not return a REGEXP>
+
+=item *
+
+C<Perl_pmflag() is deprecated, and will be removed from the XS API>
+
+=item *
+
+C<lvalue attribute ignored after the subroutine has been defined>
+
+This new warning is issued when one attempts to mark a subroutine as
+lvalue after it has been defined.
+
+=item *
+
+Perl now warns you if C<++> or C<--> are unable to change the value
+because it's beyond the limit of representation.
+
+This uses a new warnings category: "imprecision".
+
+=item *
+
+C<lc>, C<uc>, C<lcfirst>, and C<ucfirst> warn when passed undef.
+
+=item *
+
+C<Show constant in "Useless use of a constant in void context">
+
+=item *
+
+C<Prototype after '%s'>
+
+=item *
+
+C<panic: sv_chop %s>
+
+This new fatal error occurs when the C routine C<Perl_sv_chop()> was
+passed a position that is not within the scalar's string buffer. This
+could be caused by buggy XS code, and at this point recovery is not
+possible.
+
+
+=item *
+
+The fatal error C<Malformed UTF-8 returned by \N> is now produced if the
+C<charnames> handler returns malformed UTF-8.
+
+=item *
+
+If an unresolved named character or sequence was encountered when
+compiling a regex pattern then the fatal error C<\N{NAME} must be resolved
+by the lexer> is now produced. This can happen, for example, when using a
+single-quotish context like C<$re = '\N{SPACE}'; /$re/;>. See L<perldiag>
+for more examples of how the lexer can get bypassed.
+
+=item *
+
+C<Invalid hexadecimal number in \N{U+...}> is a new fatal error
+triggered when the character constant represented by C<...> is not a
+valid hexadecimal number.
+
+=item *
+
+The new meaning of C<\N> as C<[^\n]> is not valid in a bracketed character
+class, just like C<.> in a character class loses its special meaning,
+and will cause the fatal error C<\N in a character class must be a named
+character: \N{...}>.
+
+=item *
+
+The rules on what is legal for the C<...> in C<\N{...}> have been
+tightened up so that unless the C<...> begins with an alphabetic
+character and continues with a combination of alphanumerics, dashes,
+spaces, parentheses or colons then the warning C<Deprecated character(s)
+in \N{...} starting at '%s'> is now issued.
+
+=item *
+
+The warning C<Using just the first characters returned by \N{}> will
+be issued if the C<charnames> handler returns a sequence of characters
+which exceeds the limit of the number of characters that can be used. The
+message will indicate which characters were used and which were discarded.
+
+=back
+
+=back
+
+=head2 Changed Diagnostics
+
+A number of existing diagnostic messages have been improved or corrected:
+
+=over
+
+=item *
+
+A new warning category C<illegalproto> allows finer-grained control of
+warnings around function prototypes.
+
+The two warnings:
+
+=over
+
+=item C<Illegal character in prototype for %s : %s>
+
+=item C<Prototype after '%c' for %s : %s>
+
+=back
+
+have been moved from the C<syntax> top-level warnings category into a new
+first-level category, C<illegalproto>. These two warnings are currently
+the only ones emitted during parsing of an invalid/illegal prototype,
+so one can now use
+
+ no warnings 'illegalproto';
+
+to suppress only those, but not other syntax-related warnings. Warnings
+where prototypes are changed, ignored, or not met are still in the
+C<prototype> category as before.
+
+=item *
+
+C<Deep recursion on subroutine "%s">
+
+It is now possible to change the depth threshold for this warning from the
+default of 100, by recompiling the F<perl> binary, setting the C
+pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
+
+=item *
+
+C<Illegal character in prototype> warning is now more precise
+when reporting illegal characters after _
+
+=item *
+
+mro merging error messages are now very similar to those produced by
+L<Algorithm::C3>.
+
+=item *
+
+Amelioration of the error message "Unrecognized character %s in column %d"
+
+Changes the error message to "Unrecognized character %s; marked by E<lt>--
+HERE after %sE<lt>-- HERE near column %d". This should make it a little
+simpler to spot and correct the suspicious character.
+
+=item *
+
+Perl now explicitly points to C<$.> when it causes an uninitialized
+warning for ranges in scalar context.
+
+=item *
+
+C<split> now warns when called in void context.
+
+=item *
+
+C<printf>-style functions called with too few arguments will now issue the
+warning C<"Missing argument in %s"> [perl #71000]
+
+=item *
+
+Perl now properly returns a syntax error instead of segfaulting
+if C<each>, C<keys>, or C<values> is used without an argument.
+
+=item *
+
+C<tell()> now fails properly if called without an argument and when no
+previous file was read.
+
+C<tell()> now returns C<-1>, and sets errno to C<EBADF>, thus restoring
+the 5.8.x behaviour.
+
+=item *
+
+C<overload> no longer implicitly unsets fallback on repeated 'use
+overload' lines.
+
+=item *
+
+POSIX::strftime() can now handle Unicode characters in the format string.
+
+=item *
+
+The C<syntax> category was removed from 5 warnings that should only be in
+C<deprecated>.
+
+=item *
+
+Three fatal C<pack>/C<unpack> error messages have been normalized to
+C<panic: %s>
+
+=item *
+
+C<Unicode character is illegal> has been rephrased to be more accurate
+
+It now reads C<Unicode non-character is illegal in interchange> and the
+perldiag documentation has been expanded a bit.
+
+=item *
+
+Currently, all but the first of the several characters that the
+C<charnames> handler may return are discarded when used in a regular
+expression pattern bracketed character class. If this happens then the
+warning C<Using just the first character returned by \N{} in character
+class> will be issued.
+
+=item *
+
+The warning C<Missing right brace on \N{} or unescaped left brace after
+\N. Assuming the latter> will be issued if Perl encounters a C<\N{>
+but doesn't find a matching C<}>. In this case Perl doesn't know if it
+was mistakenly omitted, or if "match non-newline" followed by "match
+a C<{>" was desired. It assumes the latter because that is actually a
+valid interpretation as written, unlike the other case. If you meant
+the former, you need to add the matching right brace. If you did mean
+the latter, you can silence this warning by writing instead C<\N\{>.
+
+=item *
+
+C<gmtime> and C<localtime> called with numbers smaller than they can
+reliably handle will now issue the warnings C<gmtime(%.0f) too small>
+and C<localtime(%.0f) too small>.
+
+=back
+
+The following diagnostic messages have been removed:
+
+=over 4
+
+=item *
+
+C<Runaway format>
+
+=item *
+
+C<Can't locate package %s for the parents of %s>
+
+In general this warning it only got produced in
+conjunction with other warnings, and removing it allowed an ISA lookup
+optimisation to be added.
+
+=item *
+
+C<v-string in use/require is non-portable>
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+F<h2ph> now looks in C<include-fixed> too, which is a recent addition
+to gcc's search path.
+
+=item *
+
+F<h2xs> no longer incorrectly treats enum values like macros.
+It also now handles C++ style comments (C<//>) properly in enums.
+
+=item *
+
+F<perl5db.pl> now supports C<LVALUE> subroutines. Additionally, the
+debugger now correctly handles proxy constant subroutines, and
+subroutine stubs.
+
+=item *
+
+F<perlbug> now uses C<%Module::CoreList::bug_tracker> to print out
+upstream bug tracker URLs. If a user identifies a particular module
+as the topic of their bug report and we're able to divine the URL for
+its upstream bug tracker, perlbug now provide a message to the user
+explaining that the core copies the CPAN version directly, and provide
+the URL for reporting the bug directly to the upstream author.
+
+F<perlbug> no longer reports "Message sent" when it hasn't actually sent
+the message
+
+=item *
+
+F<perlthanks> is a new utility for sending non-bug-reports to the
+authors and maintainers of Perl. Getting nothing but bug reports can
+become a bit demoralising. If Perl 5.12 works well for you, please try
+out F<perlthanks>. It will make the developers smile.
+
+=item *
+
+Perl's developers have fixed bugs in F<a2p> having to do with the
+C<match()> operator in list context. Additionally, F<a2p> no longer
+generates code that uses the C<$[> variable.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+U+0FFFF is now a legal character in regular expressions.
+
+=item *
+
+pp_qr now always returns a new regexp SV. Resolves RT #69852.
+
+Instead of returning a(nother) reference to the (pre-compiled) regexp
+in the optree, use reg_temp_copy() to create a copy of it, and return a
+reference to that. This resolves issues about Regexp::DESTROY not being
+called in a timely fashion (the original bug tracked by RT #69852), as
+well as bugs related to blessing regexps, and of assigning to regexps,
+as described in correspondence added to the ticket.
+
+It transpires that we also need to undo the SvPVX() sharing when ithreads
+cloning a Regexp SV, because mother_re is set to NULL, instead of a
+cloned copy of the mother_re. This change might fix bugs with regexps
+and threads in certain other situations, but as yet neither tests nor
+bug reports have indicated any problems, so it might not actually be an
+edge case that it's possible to reach.
+
+=item *
+
+Several compilation errors and segfaults when perl was built with C<-Dmad>
+were fixed.
+
+=item *
+
+Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.
+
+=item *
+
+C<-t> should only return TRUE for file handles connected to a TTY
+
+The Microsoft C version of C<isatty()> returns TRUE for all character mode
+devices, including the F</dev/null>-style "nul" device and printers like
+"lpt1".
+
+=item *
+
+Fixed a regression caused by commit fafafbaf which caused a panic during
+parameter passing [perl #70171]
+
+=item *
+
+On systems which in-place edits without backup files, -i'*' now works as
+the documentation says it does [perl #70802]
+
+=item *
+
+Saving and restoring magic flags no longer loses readonly flag.
+
+=item *
+
+The malformed syntax C<grep EXPR LIST> (note the missing comma) no longer
+causes abrupt and total failure.
+
+=item *
+
+Regular expressions compiled with C<qr{}> literals properly set C<$'> when
+matching again.
+
+=item *
+
+Using named subroutines with C<sort> should no longer lead to bus errors
+[perl #71076]
+
+=item *
+
+Numerous bugfixes catch small issues caused by the recently-added Lexer API.
+
+=item *
+
+Smart match against C<@_> sometimes gave false negatives. [perl #71078]
+
+=item *
+
+C<$@> may now be assigned a read-only value (without error or busting
+the stack).
+
+=item *
+
+C<sort> called recursively from within an active comparison subroutine no
+longer causes a bus error if run multiple times. [perl #71076]
+
+=item *
+
+Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)
+
+=item *
+
+@_ and $_ no longer leak under threads (RT #34342 and #41138, also
+#70602, #70974)
+
+=item *
+
+C<-I> on shebang line now adds directories in front of @INC
+as documented, and as does C<-I> when specified on the command-line.
+
+=item *
+
+C<kill> is now fatal when called on non-numeric process identifiers.
+Previously, an C<undef> process identifier would be interpreted as a
+request to kill process 0, which would terminate the current process
+group on POSIX systems. Since process identifiers are always integers,
+killing a non-numeric process is now fatal.
+
+=item *
+
+5.10.0 inadvertently disabled an optimisation, which caused a measurable
+performance drop in list assignment, such as is often used to assign
+function parameters from C<@_>. The optimisation has been re-instated, and
+the performance regression fixed. (This fix is also present in 5.10.1)
+
+=item *
+
+Fixed memory leak on C<while (1) { map 1, 1 }> [RT #53038].
+
+=item *
+
+Some potential coredumps in PerlIO fixed [RT #57322,54828].
+
+=item *
+
+The debugger now works with lvalue subroutines.
+
+=item *
+
+The debugger's C<m> command was broken on modules that defined constants
+[RT #61222].
+
+=item *
+
+C<crypt> and string complement could return tainted values for untainted
+arguments [RT #59998].
+
+=item *
+
+The C<-i>I<.suffix> command-line switch now recreates the file using
+restricted permissions, before changing its mode to match the original
+file. This eliminates a potential race condition [RT #60904].
+
+=item *
+
+On some Unix systems, the value in C<$?> would not have the top bit set
+(C<$? & 128>) even if the child core dumped.
+
+=item *
+
+Under some circumstances, C<$^R> could incorrectly become undefined
+[RT #57042].
+
+=item *
+
+In the XS API, various hash functions, when passed a pre-computed hash where
+the key is UTF-8, might result in an incorrect lookup.
+
+=item *
+
+XS code including F<XSUB.h> before F<perl.h> gave a compile-time error
+[RT #57176].
+
+=item *
+
+C<< $object-E<gt>isa('Foo') >> would report false if the package C<Foo>
+didn't exist, even if the object's C<@ISA> contained C<Foo>.
+
+=item *
+
+Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
+C<@ISA>, have been found and fixed.
+
+=item *
+
+Bitwise operations on references could crash the interpreter, e.g.
+C<$x=\$y; $x |= "foo"> [RT #54956].
+
+=item *
+
+Patterns including alternation might be sensitive to the internal UTF-8
+representation, e.g.
+
+ my $byte = chr(192);
+ my $utf8 = chr(192); utf8::upgrade($utf8);
+ $utf8 =~ /$byte|X}/i; # failed in 5.10.0
+
+=item *
+
+Within UTF8-encoded Perl source files (i.e. where C<use utf8> is in
+effect), double-quoted literal strings could be corrupted where a C<\xNN>,
+C<\0NNN> or C<\N{}> is followed by a literal character with ordinal value
+greater than 255 [RT #59908].
+
+=item *
+
+C<B::Deparse> failed to correctly deparse various constructs:
+C<readpipe STRING> [RT #62428], C<CORE::require(STRING)> [RT #62488],
+C<sub foo(_)> [RT #62484].
+
+=item *
+
+Using C<setpgrp> with no arguments could corrupt the perl stack.
+
+=item *
+
+The block form of C<eval> is now specifically trappable by C<Safe> and
+C<ops>. Previously it was erroneously treated like string C<eval>.
+
+=item *
+
+In 5.10.0, the two characters C<[~> were sometimes parsed as the smart
+match operator (C<~~>) [RT #63854].
+
+=item *
+
+In 5.10.0, the C<*> quantifier in patterns was sometimes treated as
+C<{0,32767}> [RT #60034, #60464]. For example, this match would fail:
+
+ ("ab" x 32768) =~ /^(ab)*$/
+
+=item *
+
+C<shmget> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].
+
+=item *
+
+Using C<next> or C<last> to exit a C<given> block no longer produces a
+spurious warning like the following:
+
+ Exiting given via last at foo.pl line 123
+
+=item *
+
+Assigning a format to a glob could corrupt the format; e.g.:
+
+ *bar=*foo{FORMAT}; # foo format now bad
+
+=item *
+
+Attempting to coerce a typeglob to a string or number could cause an
+assertion failure. The correct error message is now generated,
+C<Can't coerce GLOB to I<$type>>.
+
+=item *
+
+Under C<use filetest 'access'>, C<-x> was using the wrong access
+mode. This has been fixed [RT #49003].
+
+=item *
+
+C<length> on a tied scalar that returned a Unicode value would not be
+correct the first time. This has been fixed.
+
+=item *
+
+Using an array C<tie> inside in array C<tie> could SEGV. This has been
+fixed. [RT #51636]
+
+=item *
+
+A race condition inside C<PerlIOStdio_close()> has been identified and
+fixed. This used to cause various threading issues, including SEGVs.
+
+=item *
+
+In C<unpack>, the use of C<()> groups in scalar context was internally
+placing a list on the interpreter's stack, which manifested in various
+ways, including SEGVs. This is now fixed [RT #50256].
+
+=item *
+
+Magic was called twice in C<substr>, C<\&$x>, C<tie $x, $m> and C<chop>.
+These have all been fixed.
+
+=item *
+
+A 5.10.0 optimisation to clear the temporary stack within the implicit
+loop of C<s///ge> has been reverted, as it turned out to be the cause of
+obscure bugs in seemingly unrelated parts of the interpreter [commit
+ef0d4e17921ee3de].
+
+=item *
+
+The line numbers for warnings inside C<elsif> are now correct.
+
+=item *
+
+The C<..> operator now works correctly with ranges whose ends are at or
+close to the values of the smallest and largest integers.
+
+=item *
+
+C<binmode STDIN, ':raw'> could lead to segmentation faults on some platforms.
+This has been fixed [RT #54828].
+
+=item *
+
+An off-by-one error meant that C<index $str, ...> was effectively being
+executed as C<index "$str\0", ...>. This has been fixed [RT #53746].
+
+=item *
+
+Various leaks associated with named captures in regexes have been fixed
+[RT #57024].
+
+=item *
+
+A weak reference to a hash would leak. This was affecting C<DBI>
+[RT #56908].
+
+=item *
+
+Using (?|) in a regex could cause a segfault [RT #59734].
+
+=item *
+
+Use of a UTF-8 C<tr//> within a closure could cause a segfault [RT #61520].
+
+=item *
+
+Calling C<Perl_sv_chop()> or otherwise upgrading an SV could result in an
+unaligned 64-bit access on the SPARC architecture [RT #60574].
+
+=item *
+
+In the 5.10.0 release, C<inc_version_list> would incorrectly list
+C<5.10.*> after C<5.8.*>; this affected the C<@INC> search order
+[RT #67628].
+
+=item *
+
+In 5.10.0, C<pack "a*", $tainted_value> returned a non-tainted value
+[RT #52552].
+
+=item *
+
+In 5.10.0, C<printf> and C<sprintf> could produce the fatal error
+C<panic: utf8_mg_pos_cache_update> when printing UTF-8 strings
+[RT #62666].
+
+=item *
+
+In the 5.10.0 release, a dynamically created C<AUTOLOAD> method might be
+missed (method cache issue) [RT #60220,60232].
+
+=item *
+
+In the 5.10.0 release, a combination of C<use feature> and C<//ee> could
+cause a memory leak [RT #63110].
+
+=item *
+
+C<-C> on the shebang (C<#!>) line is once more permitted if it is also
+specified on the command line. C<-C> on the shebang line used to be a
+silent no-op I<if> it was not also on the command line, so perl 5.10.0
+disallowed it, which broke some scripts. Now perl checks whether it is
+also on the command line and only dies if it is not [RT #67880].
+
+=item *
+
+In 5.10.0, certain types of re-entrant regular expression could crash,
+or cause the following assertion failure [RT #60508]:
+
+ Assertion rx->sublen >= (s - rx->subbeg) + i failed
+
+=item *
+
+Perl now includes previously missing files from the Unicode Character
+Database.
+
+=item *
+
+Perl now honors C<TMPDIR> when opening an anonymous temporary file.
+
+=back
+
+
+=head1 Platform Specific Changes
+
+Perl is incredibly portable. In general, if a platform has a C compiler,
+someone has ported Perl to it (or will soon). We're happy to announce
+that Perl 5.12 includes support for several new platforms. At the same
+time, it's time to bid farewell to some (very) old friends.
+
+=head2 New Platforms
+
+=over
+
+=item Haiku
+
+Perl's developers have merged patches from Haiku's maintainers. Perl
+should now build on Haiku.
+
+=item MirOS BSD
+
+Perl should now build on MirOS BSD.
+
+=back
+
+=head2 Discontinued Platforms
+
+=over
+
+=item Domain/OS
+
+=item MiNT
+
+=item Tenon MachTen
+
+=back
+
+=head2 Updated Platforms
+
+=over 4
+
+=item AIX
+
+=over 4
+
+=item *
+
+Removed F<libbsd> for AIX 5L and 6.1. Only C<flock()> was used from
+F<libbsd>.
+
+=item *
+
+Removed F<libgdbm> for AIX 5L and 6.1 if F<libgdbm> < 1.8.3-5 is
+installed. The F<libgdbm> is delivered as an optional package with the
+AIX Toolbox. Unfortunately the versions below 1.8.3-5 are broken.
+
+=item *
+
+Hints changes mean that AIX 4.2 should work again.
+
+=back
+
+=item Cygwin
+
+=over 4
+
+=item *
+
+Perl now supports IPv6 on Cygwin 1.7 and newer.
+
+=item *
+
+On Cygwin we now strip the last number from the DLL. This has been the
+behaviour in the cygwin.com build for years. The hints files have been
+updated.
+
+=back
+
+=item Darwin (Mac OS X)
+
+=over 4
+
+=item *
+
+Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),
+as it's still buggy.
+
+=item *
+
+Correct infelicities in the regexp used to identify buggy locales
+on Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).
+
+=back
+
+=item DragonFly BSD
+
+=over 4
+
+=item *
+
+Fix thread library selection [perl #69686]
+
+=back
+
+=item FreeBSD
+
+=over 4
+
+=item *
+
+The hints files now identify the correct threading libraries on FreeBSD 7
+and later.
+
+=back
+
+=item Irix
+
+=over 4
+
+=item *
+
+We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
+C<cc -E -> unfortunately goes into K&R mode, but C<cc -E file.c> doesn't.
+
+=back
+
+=item NetBSD
+
+=over 4
+
+=item *
+
+Hints now supports versions 5.*.
+
+=back
+
+=item OpenVMS
+
+=over 4
+
+=item *
+
+C<-UDEBUGGING> is now the default on VMS.
+
+Like it has been everywhere else for ages and ages. Also make command-line
+selection of -UDEBUGGING and -DDEBUGGING work in configure.com; before
+the only way to turn it off was by saying no in answer to the interactive
+question.
+
+=item *
+
+The default pipe buffer size on VMS has been updated to 8192 on 64-bit
+systems.
+
+=item *
+
+Reads from the in-memory temporary files of C<PerlIO::scalar> used to fail
+if C<$/> was set to a numeric reference (to indicate record-style reads).
+This is now fixed.
+
+=item *
+
+VMS now supports C<getgrgid>.
+
+=item *
+
+Many improvements and cleanups have been made to the VMS file name handling
+and conversion code.
+
+=item *
+
+Enabling the C<PERL_VMS_POSIX_EXIT> logical name now encodes a POSIX exit
+status in a VMS condition value for better interaction with GNV's bash
+shell and other utilities that depend on POSIX exit values. See
+L<perlvms/"$?"> for details.
+
+=item *
+
+C<File::Copy> now detects Unix compatibility mode on VMS.
+
+=back
+
+=item Stratus VOS
+
+=over 4
+
+=item *
+
+Various changes from Stratus have been merged in.
+
+=back
+
+=item Symbian
+
+=over 4
+
+=item *
+
+There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.
+
+=back
+
+=item Windows
+
+=over 4
+
+=item *
+
+Perl 5.12 supports Windows 2000 and later. The supporting code for
+legacy versions of Windows is still included, but will be removed
+during the next development cycle.
+
+=item *
+
+Initial support for building Perl with MinGW-w64 is now available.
+
+=item *
+
+F<perl.exe> now includes a manifest resource to specify the C<trustInfo>
+settings for Windows Vista and later. Without this setting Windows
+would treat F<perl.exe> as a legacy application and apply various
+heuristics like redirecting access to protected file system areas
+(like the "Program Files" folder) to the users "VirtualStore"
+instead of generating a proper "permission denied" error.
+
+The manifest resource also requests the Microsoft Common-Controls
+version 6.0 (themed controls introduced in Windows XP). Check out the
+Win32::VisualStyles module on CPAN to switch back to old style
+unthemed controls for legacy applications.
+
+=item *
+
+The C<-t> filetest operator now only returns true if the filehandle
+is connected to a console window. In previous versions of Perl it
+would return true for all character mode devices, including F<NUL>
+and F<LPT1>.
+
+=item *
+
+The C<-p> filetest operator now works correctly, and the
+Fcntl::S_IFIFO constant is defined when Perl is compiled with
+Microsoft Visual C. In previous Perl versions C<-p> always
+returned a false value, and the Fcntl::S_IFIFO constant
+was not defined.
+
+This bug is specific to Microsoft Visual C and never affected
+Perl binaries built with MinGW.
+
+=item *
+
+The socket error codes are now more widely supported: The POSIX
+module will define the symbolic names, like POSIX::EWOULDBLOCK,
+and stringification of socket error codes in $! works as well
+now;
+
+ C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
+ A non-blocking socket operation could not be completed immediately.
+
+=item *
+
+flock() will now set sensible error codes in $!. Previous Perl versions
+copied the value of $^E into $!, which caused much confusion.
+
+=item *
+
+select() now supports all empty C<fd_set>s more correctly.
+
+=item *
+
+C<'.\foo'> and C<'..\foo'> were treated differently than
+C<'./foo'> and C<'../foo'> by C<do> and C<require> [RT #63492].
+
+=item *
+
+Improved message window handling means that C<alarm> and C<kill> messages
+will no longer be dropped under race conditions.
+
+=item *
+
+Various bits of Perl's build infrastructure are no longer converted to
+win32 line endings at release time. If this hurts you, please report the
+problem with the L<perlbug> program included with perl.
+
+=back
+
+=back
+
+
+=head1 Known Problems
+
+This is a list of some significant unfixed bugs, which are regressions
+from either 5.10.x or 5.8.x.
+
+=over 4
+
+=item *
+
+Some CPANPLUS tests may fail if there is a functioning file
+F<../../cpanp-run-perl> outside your build directory. The failure
+shouldn't imply there's a problem with the actual functional
+software. The bug is already fixed in [RT #74188] and is scheduled for
+inclusion in perl-v5.12.1.
+
+=item *
+
+C<List::Util::first> misbehaves in the presence of a lexical C<$_>
+(typically introduced by C<my $_> or implicitly by C<given>). The variable
+which gets set for each iteration is the package variable C<$_>, not the
+lexical C<$_> [RT #67694].
+
+A similar issue may occur in other modules that provide functions which
+take a block as their first argument, like
+
+ foo { ... $_ ...} list
+
+=item *
+
+Some regexes may run much more slowly when run in a child thread compared
+with the thread the pattern was compiled into [RT #55600].
+
+=item *
+
+Things like C<"\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/>
+will appear to hang as they get into a very long running loop [RT #72998].
+
+=item *
+
+Several porters have reported mysterious crashes when Perl's entire
+test suite is run after a build on certain Windows 2000 systems. When
+run by hand, the individual tests reportedly work fine.
+
+=back
+
+=head1 Errata
+
+=over
+
+=item *
+
+This one is actually a change introduced in 5.10.0, but it was missed
+from that release's perldelta, so it is mentioned here instead.
+
+A bugfix related to the handling of the C</m> modifier and C<qr> resulted
+in a change of behaviour between 5.8.x and 5.10.0:
+
+ # matches in 5.8.x, doesn't match in 5.10.0
+ $re = qr/^bar/; "foo\nbar" =~ /$re/m;
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.12.0 represents approximately two years of development since
+Perl 5.10.0 and contains over 750,000 lines of changes across over
+3,000 files from over 200 authors and committers.
+
+Perl continues to flourish into its third decade thanks to a vibrant
+community of users and developers. The following people are known to
+have contributed the improvements that became Perl 5.12.0:
+
+Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,
+Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, Alexandr
+Ciornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,
+andrew@sundale.net, Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,
+Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,
+Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,
+Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, Chris
+Williams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,
+Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,
+Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,
+David Mitchell, David M. Syzdek, David Nicol, David Wheeler, Dennis
+Kaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,
+Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,
+Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, George
+Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,
+Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,
+Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,
+Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,
+Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,
+John Peacock, John Peacock via RT, John P. Linderman, John Wright,
+Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, Ken
+Williams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,
+Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, Mark
+Jason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,
+Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, Michael
+G Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,
+Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,
+Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,
+Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,
+Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,
+Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, Risto
+Kankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIRO
+Tomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, Sébastien
+Aperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'
+Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steffen
+Ullrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,
+The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,
+Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,
+Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,
+Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus
+
+This is woefully incomplete as it's automatically generated from version
+control history. In particular, it doesn't include the names of the
+(very much appreciated) contributors who reported issues in previous
+versions of Perl that helped make Perl 5.12.0 better. For a more complete
+list of all of Perl's historical contributors, please see the C<AUTHORS>
+file in the Perl 5.12.0 distribution.
+
+Our "retired" pumpkings Nicholas Clark and Rafael Garcia-Suarez
+deserve special thanks for their brilliant and substantive ongoing
+contributions. Nicholas personally authored over 30% of the patches
+since 5.10.0. Rafael comes in second in patch authorship with 11%,
+but is first by a long shot in committing patches authored by others,
+pushing 44% of the commits since 5.10.0 in this category, often after
+providing considerable coaching to the patch authors. These statistics
+in no way comprise all of their contributions, but express in shorthand
+that we couldn't have done it without them.
+
+Many of the changes included in this version originated in the CPAN
+modules included in Perl's core. We're grateful to the entire CPAN
+community for helping Perl to flourish.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at L<http://rt.perl.org/perlbug/>. There may also be
+information at L<http://www.perl.org/>, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analyzed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+L<http://dev.perl.org/perl5/errata.html> for a list of issues
+found after this release, as well as a list of CPAN modules known
+to be incompatible with this release.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5121delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5121delta.pod
new file mode 100644
index 00000000000..2c8a08fb289
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5121delta.pod
@@ -0,0 +1,412 @@
+=encoding utf8
+
+=head1 NAME
+
+perldelta - what is new for perl v5.12.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.12.0 release and
+the 5.12.1 release.
+
+If you are upgrading from an earlier release such as 5.10.1, first read
+L<perl5120delta>, which describes differences between 5.10.1 and
+5.12.0.
+
+=head1 Incompatible Changes
+
+There are no changes intentionally incompatible with 5.12.0. If any
+incompatibilities with 5.12.0 exist, they are bugs. Please report them.
+
+=head1 Core Enhancements
+
+Other than the bug fixes listed below, there should be no user-visible
+changes to the core language in this release.
+
+=head1 Modules and Pragmata
+
+=head2 Pragmata Changes
+
+=over
+
+=item *
+
+We fixed exporting of C<is_strict> and C<is_lax> from L<version>.
+
+These were being exported with a wrapper that treated them as method
+calls, which caused them to fail. They are just functions, are
+documented as such, and should never be subclassed, so this patch
+just exports them directly as functions without the wrapper.
+
+=back
+
+=head2 Updated Modules
+
+=over
+
+=item *
+
+We upgraded L<CGI.pm> to version 3.49 to incorporate fixes for regressions
+introduced in the release we shipped with Perl 5.12.0.
+
+=item *
+
+We upgraded L<Pod::Simple> to version 3.14 to get an improvement to \C\<\< \>\>
+parsing.
+
+=item *
+
+We made a small fix to the L<CPANPLUS> test suite to fix an occasional spurious test failure.
+
+=item *
+
+We upgraded L<Safe> to version 2.27 to wrap coderefs retured by C<reval()> and C<rdo()>.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+=over
+
+=item *
+
+We added the new maintenance release policy to L<perlpolicy.pod>
+
+=item *
+
+We've clarified the multiple-angle-bracket construct in the spec for POD
+in L<perlpodspec>
+
+=item *
+
+We added a missing explanation for a warning about C<:=> to L<perldiag.pod>
+
+=item *
+
+We removed a false claim in L<perlunitut> that all text strings are Unicode strings in Perl.
+
+=item *
+
+We updated the Github mirror link in L<perlrepository> to mirrors/perl, not github/perl
+
+=item *
+
+We fixed a a minor error in L<perl5114delta.pod>.
+
+=item *
+
+We replaced a mention of the now-obsolete L<Switch.pm> with F<given>/F<when>.
+
+=item *
+
+We improved documentation about F<$sitelibexp/sitecustomize.pl> in L<perlrun>.
+
+=item *
+
+We corrected L<perlmodlib.pod> which had unintentionally omitted a number of modules.
+
+=item *
+
+We updated the documentation for 'require' in L<perlfunc.pod> relating to putting Perl code in @INC.
+
+=item *
+
+We reinstated some erroneously-removed documentation about quotemeta in L<perlfunc>.
+
+=item *
+
+We fixed an F<a2p> example in L<perlutil.pod>.
+
+=item *
+
+We filled in a blank in L<perlport.pod> with the release date of Perl 5.12.
+
+=item *
+
+We fixed broken links in a number of perldelta files.
+
+=item *
+
+The documentation for L<Carp.pm> incorrectly stated that the $Carp::Verbose
+variable makes cluck generate stack backtraces.
+
+=item *
+
+We fixed a number of typos in L<Pod::Functions>
+
+=item *
+
+We improved documentation of case-changing functions in L<perlfunc.pod>
+
+=item *
+
+We corrected L<perlgpl.pod> to contain the correct version of the GNU
+General Public License.
+
+
+
+=back
+
+=head1 Testing
+
+=head2 Testing Improvements
+
+=over
+
+=item *
+
+F<t/op/sselect.t> is now less prone to clock jitter during timing checks
+on Windows.
+
+sleep() time on Win32 may be rounded down to multiple of
+the clock tick interval.
+
+=item *
+
+F<lib/blib.t> and F<lib/locale.t>: Fixes for test failures on Darwin/PPC
+
+=item *
+
+F<perl5db.t>: Fix for test failures when C<Term::ReadLine::Gnu> is installed.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Configuration improvements
+
+=over
+
+=item *
+
+We updated F<INSTALL> with notes about how to deal with broken F<dbm.h>
+on OpenSUSE (and possibly other platforms)
+
+=back
+
+=head1 Bug Fixes
+
+=over 4
+
+=item *
+
+A bug in how we process filetest operations could cause a segfault.
+Filetests don't always expect an op on the stack, so we now use
+TOPs only if we're sure that we're not stat'ing the _ filehandle.
+This is indicated by OPf_KIDS (as checked in ck_ftst).
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=74542>
+
+=item *
+
+When deparsing a nextstate op that has both a change of package (relative
+to the previous nextstate) and a label, the package declaration is now
+emitted first, because it is syntactically impermissible for a label to
+prefix a package declaration.
+
+=item *
+
+XSUB.h now correctly redefines fgets under PERL_IMPLICIT_SYS
+
+See also: L<http://rt.cpan.org/Public/Bug/Display.html?id=55049>
+
+
+=item *
+
+utf8::is_utf8 now respects GMAGIC (e.g. $1)
+
+
+=item *
+
+XS code using C<fputc()> or C<fputs()>: on Windows could cause an error
+due to their arguments being swapped.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=72704>
+
+=item *
+
+We fixed a small bug in lex_stuff_pvn() that caused spurious syntax errors
+in an obscure situation. It happened when stuffing was performed on the
+last line of a file and the line ended with a statement that lacked a
+terminating semicolon.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=74006>
+
+=item *
+
+We fixed a bug that could cause \N{} constructs followed by a single . to
+be parsed incorrectly.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=74978>
+
+=item *
+
+
+We fixed a bug that caused when(scalar) without an argument not to be
+treated as a syntax error.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=74114>
+
+=item *
+
+We fixed a regression in the handling of labels immediately before string
+evals that was introduced in Perl 5.12.0.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=74290>
+
+=item *
+
+We fixed a regression in case-insensitive matching of folded characters
+in regular expressions introduced in Perl 5.12.0.
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=72998>
+
+=back
+
+=head1 Platform Specific Notes
+
+=head2 HP-UX
+
+=over
+
+=item *
+
+Perl now allows -Duse64bitint without promoting to use64bitall on HP-UX
+
+=back
+
+=head2 AIX
+
+=over
+
+=item *
+
+Perl now builds on AIX 4.2
+
+The changes required work around AIX 4.2s' lack of support for IPv6,
+and limited support for POSIX C<sigaction()>.
+
+=back
+
+=head2 FreeBSD 7
+
+=over
+
+=item *
+
+FreeBSD 7 no longer contains F</usr/bin/objformat>. At build time,
+Perl now skips the F<objformat> check for versions 7 and higher and
+assumes ELF.
+
+=back
+
+=head2 VMS
+
+=over
+
+=item *
+
+It's now possible to build extensions on older (pre 7.3-2) VMS systems.
+
+DCL symbol length was limited to 1K up until about seven years or
+so ago, but there was no particularly deep reason to prevent those
+older systems from configuring and building Perl.
+
+=item *
+
+We fixed the previously-broken C<-Uuseperlio> build on VMS.
+
+We were checking a variable that doesn't exist in the non-default
+case of disabling perlio. Now we only look at it when it exists.
+
+=item *
+
+We fixed the -Uuseperlio command-line option in configure.com.
+
+Formerly it only worked if you went through all the questions
+interactively and explicitly answered no.
+
+=back
+
+=head1 Known Problems
+
+=over
+
+=item *
+
+C<List::Util::first> misbehaves in the presence of a lexical C<$_>
+(typically introduced by C<my $_> or implicitly by C<given>). The variable
+which gets set for each iteration is the package variable C<$_>, not the
+lexical C<$_>.
+
+A similar issue may occur in other modules that provide functions which
+take a block as their first argument, like
+
+ foo { ... $_ ...} list
+
+See also: L<http://rt.perl.org/rt3/Public/Bug/Display.html?id=67694>
+
+=item *
+
+C<Module::Load::Conditional> and C<version> have an unfortunate
+interaction which can cause C<CPANPLUS> to crash when it encounters
+an unparseable version string. Upgrading to C<CPANPLUS> 0.9004 or
+C<Module::Load::Conditional> 0.38 from CPAN will resolve this issue.
+
+=back
+
+
+=head1 Acknowledgements
+
+Perl 5.12.1 represents approximately four weeks of development since
+Perl 5.12.0 and contains approximately 4,000 lines of changes
+across 142 files from 28 authors.
+
+Perl continues to flourish into its third decade thanks to a vibrant
+community of users and developers. The following people are known to
+have contributed the improvements that became Perl 5.12.1:
+
+Ævar Arnfjörð Bjarmason, Chris Williams, chromatic, Craig A. Berry,
+David Golden, Father Chrysostomos, Florian Ragwitz, Frank Wiegand,
+Gene Sullivan, Goro Fuji, H.Merijn Brand, James E Keenan, Jan Dubois,
+Jesse Vincent, Josh ben Jore, Karl Williamson, Leon Brocard, Michael
+Schwern, Nga Tang Chan, Nicholas Clark, Niko Tyni, Philippe Bruhat,
+Rafael Garcia-Suarez, Ricardo Signes, Steffen Mueller, Todd Rinaldo,
+Vincent Pit and Zefram.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5122delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5122delta.pod
new file mode 100644
index 00000000000..9a150cc0100
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5122delta.pod
@@ -0,0 +1,346 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5122delta - what is new for perl v5.12.2
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.12.1 release and
+the 5.12.2 release.
+
+If you are upgrading from an earlier major version, such as 5.10.1,
+first read L<perl5120delta>, which describes differences between 5.10.1
+and 5.12.0, as well as L<perl5121delta>, which describes earlier changes
+in the 5.12 stable release series.
+
+=head1 Incompatible Changes
+
+There are no changes intentionally incompatible with 5.12.1. If any exist, they
+are bugs and reports are welcome.
+
+=head1 Core Enhancements
+
+Other than the bug fixes listed below, there should be no user-visible
+changes to the core language in this release.
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+This release does not introduce any new modules or pragmata.
+
+=head2 Pragmata Changes
+
+In the previous release, C<no I<VERSION>;> statements triggered a bug
+which could cause L<feature> bundles to be loaded and L<strict> mode to
+be enabled unintentionally.
+
+=head2 Updated Modules
+
+=over 4
+
+=item C<Carp>
+
+Upgraded from version 1.16 to 1.17.
+
+L<Carp> now detects incomplete L<caller()|perlfunc/"caller EXPR">
+overrides and avoids using bogus C<@DB::args>. To provide backtraces, Carp
+relies on particular behaviour of the caller built-in. Carp now detects
+if other code has overridden this with an incomplete implementation, and
+modifies its backtrace accordingly. Previously incomplete overrides would
+cause incorrect values in backtraces (best case), or obscure fatal errors
+(worst case)
+
+This fixes certain cases of C<Bizarre copy of ARRAY> caused by modules
+overriding C<caller()> incorrectly.
+
+=item C<CPANPLUS>
+
+A patch to F<cpanp-run-perl> has been backported from CPANPLUS C<0.9004>. This
+resolves L<[perl #55964]|http://rt.perl.org/rt3/Ticket/Display.html?id=55964>
+and L<[perl #57106]|http://rt.perl.org/rt3/Ticket/Display.html?id=57106>, both
+of which related to failures to install distributions that use
+C<Module::Install::DSL>.
+
+=item C<File::Glob>
+
+A regression which caused a failure to find C<CORE::GLOBAL::glob> after
+loading C<File::Glob> to crash has been fixed. Now, it correctly falls back
+to external globbing via C<pp_glob>.
+
+=item C<File::Copy>
+
+C<File::Copy::copy(FILE, DIR)> is now documented.
+
+=item C<File::Spec>
+
+Upgraded from version 3.31 to 3.31_01.
+
+Several portability fixes were made in C<File::Spec::VMS>: a colon is now
+recognized as a delimiter in native filespecs; caret-escaped delimiters are
+recognized for better handling of extended filespecs; C<catpath()> returns
+an empty directory rather than the current directory if the input directory
+name is empty; C<abs2rel()> properly handles Unix-style input.
+
+=back
+
+=head1 Utility Changes
+
+=over
+
+=item *
+
+F<perlbug> now always gives the reporter a chance to change the email address it
+guesses for them.
+
+=item *
+
+F<perlbug> should no longer warn about uninitialized values when using the C<-d>
+and C<-v> options.
+
+=back
+
+=head1 Changes to Existing Documentation
+
+=over
+
+=item *
+
+The existing policy on backward-compatibility and deprecation has
+been added to L<perlpolicy>, along with definitions of terms like
+I<deprecation>.
+
+=item *
+
+L<perlfunc/srand>'s usage has been clarified.
+
+=item *
+
+The entry for L<perlfunc/die> was reorganized to emphasize its
+role in the exception mechanism.
+
+=item *
+
+Perl's L<INSTALL> file has been clarified to explicitly state that Perl
+requires a C89 compliant ANSI C Compiler.
+
+=item *
+
+L<IO::Socket>'s C<getsockopt()> and C<setsockopt()> have been documented.
+
+=item *
+
+F<alarm()>'s inability to interrupt blocking IO on Windows has been documented.
+
+=item *
+
+L<Math::TrulyRandom> hasn't been updated since 1996 and has been removed
+as a recommended solution for random number generation.
+
+=item *
+
+L<perlrun> has been updated to clarify the behaviour of octal flags to F<perl>.
+
+=item *
+
+To ease user confusion, C<$#> and C<$*>, two special variables that were
+removed in earlier versions of Perl have been documented.
+
+=item *
+
+The version of L<perlfaq> shipped with the Perl core has been updated from the
+official FAQ version, which is now maintained in the C<briandfoy/perlfaq>
+branch of the Perl repository at L<git://perl5.git.perl.org/perl.git>.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Configuration improvements
+
+=over
+
+=item *
+
+The C<d_u32align> configuration probe on ARM has been fixed.
+
+=back
+
+=head2 Compilation improvements
+
+=over
+
+=item *
+
+An "C<incompatible operand types>" error in ternary expressions when building
+with C<clang> has been fixed.
+
+=item *
+
+Perl now skips setuid C<File::Copy> tests on partitions it detects to be mounted
+as C<nosuid>.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+A possible segfault in the C<T_PRTOBJ> default typemap has been fixed.
+
+=item *
+
+A possible memory leak when using L<caller()|perlfunc/"caller EXPR"> to set
+C<@DB::args> has been fixed.
+
+=item *
+
+Several memory leaks when loading XS modules were fixed.
+
+=item *
+
+C<unpack()> now handles scalar context correctly for C<%32H> and C<%32u>,
+fixing a potential crash. C<split()> would crash because the third item
+on the stack wasn't the regular expression it expected. C<unpack("%2H",
+...)> would return both the unpacked result and the checksum on the stack,
+as would C<unpack("%2u", ...)>.
+L<[perl #73814]|http://rt.perl.org/rt3/Ticket/Display.html?id=73814>
+
+=item *
+
+Perl now avoids using memory after calling C<free()> in F<pp_require>
+when there are CODEREFs in C<@INC>.
+
+=item *
+
+A bug that could cause "C<Unknown error>" messages when
+"C<call_sv(code, G_EVAL)>" is called from an XS destructor has been fixed.
+
+=item *
+
+The implementation of the C<open $fh, 'E<gt>' \$buffer> feature
+now supports get/set magic and thus tied buffers correctly.
+
+=item *
+
+The C<pp_getc>, C<pp_tell>, and C<pp_eof> opcodes now make room on the
+stack for their return values in cases where no argument was passed in.
+
+=item *
+
+When matching unicode strings under some conditions inappropriate backtracking would
+result in a C<Malformed UTF-8 character (fatal)> error. This should no longer occur.
+See L<[perl #75680]|http://rt.perl.org/rt3/Public/Bug/Display.html?id=75680>
+
+=back
+
+=head1 Platform Specific Notes
+
+=head2 AIX
+
+=over
+
+=item *
+
+F<README.aix> has been updated with information about the XL C/C++ V11 compiler
+suite.
+
+=back
+
+=head2 Windows
+
+=over
+
+=item *
+
+When building Perl with the mingw64 x64 cross-compiler C<incpath>,
+C<libpth>, C<ldflags>, C<lddlflags> and C<ldflags_nolargefiles> values
+in F<Config.pm> and F<Config_heavy.pl> were not previously not being set
+correctly because, with that compiler, the include and lib directories
+are not immediately below C<$(CCHOME)>.
+
+=back
+
+=head2 VMS
+
+=over
+
+=item *
+
+F<git_version.h> is now installed on VMS. This was an oversight in v5.12.0 which
+caused some extensions to fail to build.
+
+=item *
+
+Several memory leaks in L<stat()|perlfunc/"stat FILEHANDLE"> have been fixed.
+
+=item *
+
+A memory leak in C<Perl_rename()> due to a double allocation has been
+fixed.
+
+=item *
+
+A memory leak in C<vms_fid_to_name()> (used by C<realpath()> and
+C<realname()>) has been fixed.
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.12.2 represents approximately three months of development since
+Perl 5.12.1 and contains approximately 2,000 lines of changes across
+100 files from 36 authors.
+
+Perl continues to flourish into its third decade thanks to a vibrant
+community of users and developers. The following people are known to
+have contributed the improvements that became Perl 5.12.2:
+
+Abigail, Ævar Arnfjörð Bjarmason, Ben Morrow, brian d foy, Brian
+Phillips, Chas. Owens, Chris 'BinGOs' Williams, Chris Williams,
+Craig A. Berry, Curtis Jewell, Dan Dascalescu, David Golden, David
+Mitchell, Father Chrysostomos, Florian Ragwitz, George Greer, H.Merijn
+Brand, Jan Dubois, Jesse Vincent, Jim Cromie, Karl Williamson, Lars
+Dɪᴇᴄᴋá´á´¡ 迪拉斯, Leon Brocard, Maik Hentsche, Matt S Trout,
+Nicholas Clark, Rafael Garcia-Suarez, Rainer Tammer, Ricardo Signes,
+Salvador Ortiz Garcia, Sisyphus, Slaven Rezic, Steffen Mueller, Tony Cook,
+Vincent Pit and Yves Orton.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl5123delta.pod b/Master/tlpkg/tlperl/lib/pods/perl5123delta.pod
new file mode 100644
index 00000000000..20d38bb15ca
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl5123delta.pod
@@ -0,0 +1,116 @@
+=encoding utf8
+
+=head1 NAME
+
+perldelta - what is new for perl v5.12.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.12.2 release and
+the 5.12.3 release.
+
+If you are upgrading from an earlier release such as 5.12.1, first read
+L<perl5122delta>, which describes differences between 5.12.1 and
+5.12.2. The major changes made in 5.12.0 are described in L<perl5120delta>.
+
+=head1 Incompatible Changes
+
+ There are no changes intentionally incompatible with 5.12.2. If any
+ exist, they are bugs and reports are welcome.
+
+=head1 Core Enhancements
+
+=head2 C<keys>, C<values> work on arrays
+
+You can now use the C<keys>, C<values>, C<each> builtin functions on arrays
+(previously you could only use them on hashes). See L<perlfunc> for details.
+This is actually a change introduced in perl 5.12.0, but it was missed from
+that release's perldelta.
+
+=head1 Bug Fixes
+
+"no VERSION" will now correctly deparse with B::Deparse, as will certain
+constant expressions.
+
+Module::Build should be more reliably pass its tests under cygwin.
+
+lvalue sub return values are now COW.
+
+=head1 Platform Specific Notes
+
+=over 4
+
+=item Solaris
+
+A separate DTrace is now build for miniperl, which means that perl can be
+compiled with -Dusedtrace on Solaris again.
+
+=item VMS
+
+A number of regressions on VMS have been fixed. In addition to minor cleanup
+of questionable expressions in F<vms.c>, file permissions should no longer be
+garbled by the PerlIO layer, and spurious record boundaries should no longer be
+introduced by the PerlIO layer during output.
+
+For more details and discussion on the latter, see:
+
+ http://www.nntp.perl.org/group/perl.vmsperl/2010/11/msg15419.html
+
+=item VOS
+
+A few very small changes were made to the build process on VOS to better
+support the platform. Longer-than-32-character filenames are now supported on
+OpenVOS, and build properly without IPv6 support.
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.12.3 represents approximately four months of development since
+Perl 5.12.2 and contains approximately 2500 lines of changes across
+54 files from 16 authors.
+
+Perl continues to flourish into its third decade thanks to a vibrant
+community of users and developers. The following people are known to
+have contributed the improvements that became Perl 5.12.3:
+
+Craig A. Berry, David Golden, David Leadbeater, Father Chrysostomos, Florian
+Ragwitz, Jesse Vincent, Karl Williamson, Nick Johnston, Nicolas Kaiser, Paul
+Green, Rafael Garcia-Suarez, Rainer Tammer, Ricardo Signes, Steffen Mueller,
+Zsbán Ambrus, Ævar Arnfjörð Bjarmason
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl561delta.pod b/Master/tlpkg/tlperl/lib/pods/perl561delta.pod
new file mode 100644
index 00000000000..72c38f15a9b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl561delta.pod
@@ -0,0 +1,3661 @@
+=head1 NAME
+
+perl561delta - what's new for perl v5.6.x
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.005 release and the 5.6.1
+release.
+
+=head1 Summary of changes between 5.6.0 and 5.6.1
+
+This section contains a summary of the changes between the 5.6.0 release
+and the 5.6.1 release. More details about the changes mentioned here
+may be found in the F<Changes> files that accompany the Perl source
+distribution. See L<perlhack> for pointers to online resources where you
+can inspect the individual patches described by these changes.
+
+=head2 Security Issues
+
+suidperl will not run /bin/mail anymore, because some platforms have
+a /bin/mail that is vulnerable to buffer overflow attacks.
+
+Note that suidperl is neither built nor installed by default in
+any recent version of perl. Use of suidperl is highly discouraged.
+If you think you need it, try alternatives such as sudo first.
+See http://www.courtesan.com/sudo/ .
+
+=head2 Core bug fixes
+
+This is not an exhaustive list. It is intended to cover only the
+significant user-visible changes.
+
+=over
+
+=item C<UNIVERSAL::isa()>
+
+A bug in the caching mechanism used by C<UNIVERSAL::isa()> that affected
+base.pm has been fixed. The bug has existed since the 5.005 releases,
+but wasn't tickled by base.pm in those releases.
+
+=item Memory leaks
+
+Various cases of memory leaks and attempts to access uninitialized memory
+have been cured. See L</"Known Problems"> below for further issues.
+
+=item Numeric conversions
+
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances.
+
+In other situations, large unsigned numbers (those above 2**31) could
+sometimes lose their unsignedness, causing bogus results in arithmetic
+operations.
+
+Integer modulus on large unsigned integers sometimes returned
+incorrect values.
+
+Perl 5.6.0 generated "not a number" warnings on certain conversions where
+previous versions didn't.
+
+These problems have all been rectified.
+
+Infinity is now recognized as a number.
+
+=item qw(a\\b)
+
+In Perl 5.6.0, qw(a\\b) produced a string with two backslashes instead
+of one, in a departure from the behavior in previous versions. The
+older behavior has been reinstated.
+
+=item caller()
+
+caller() could cause core dumps in certain situations. Carp was sometimes
+affected by this problem.
+
+=item Bugs in regular expressions
+
+Pattern matches on overloaded values are now handled correctly.
+
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected.
+
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better.
+
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better.
+
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed.
+
+Use of $& could trigger a core dump under some situations. This
+is now avoided.
+
+Match variables $1 et al., weren't being unset when a pattern match
+was backtracking, and the anomaly showed up inside C</...(?{ ... }).../>
+etc. These variables are now tracked correctly.
+
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly.
+
+=item "slurp" mode
+
+readline() on files opened in "slurp" mode could return an extra "" at
+the end in certain situations. This has been corrected.
+
+=item Autovivification of symbolic references to special variables
+
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now.
+
+=item Lexical warnings
+
+Lexical warnings now propagate correctly into C<eval "...">.
+
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected.
+
+Lexical warnings could leak into other scopes in some situations.
+This is now fixed.
+
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings.
+
+=item Spurious warnings and errors
+
+Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
+when statically building extensions into perl. This has been corrected.
+
+"our" variables could result in bogus "Variable will not stay shared"
+warnings. This is now fixed.
+
+"our" variables of the same name declared in two sibling blocks
+resulted in bogus warnings about "redeclaration" of the variables.
+The problem has been corrected.
+
+=item glob()
+
+Compatibility of the builtin glob() with old csh-based glob has been
+improved with the addition of GLOB_ALPHASORT option. See C<File::Glob>.
+
+File::Glob::glob() has been renamed to File::Glob::bsd_glob()
+because the name clashes with the builtin glob(). The older
+name is still available for compatibility, but is deprecated.
+
+Spurious syntax errors generated in certain situations, when glob()
+caused File::Glob to be loaded for the first time, have been fixed.
+
+=item Tainting
+
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
+
+The tainting behavior of sprintf() has been rationalized. It does
+not taint the result of floating point formats anymore, making the
+behavior consistent with that of string interpolation.
+
+=item sort()
+
+Arguments to sort() weren't being provided the right wantarray() context.
+The comparison block is now run in scalar context, and the arguments to
+be sorted are always provided list context.
+
+sort() is also fully reentrant, in the sense that the sort function
+can itself call sort(). This did not work reliably in previous releases.
+
+=item #line directives
+
+#line directives now work correctly when they appear at the very
+beginning of C<eval "...">.
+
+=item Subroutine prototypes
+
+The (\&) prototype now works properly.
+
+=item map()
+
+map() could get pathologically slow when the result list it generates
+is larger than the source list. The performance has been improved for
+common scenarios.
+
+=item Debugger
+
+Debugger exit code now reflects the script exit code.
+
+Condition C<"0"> in breakpoints is now treated correctly.
+
+The C<d> command now checks the line number.
+
+C<$.> is no longer corrupted by the debugger.
+
+All debugger output now correctly goes to the socket if RemotePort
+is set.
+
+=item PERL5OPT
+
+PERL5OPT can be set to more than one switch group. Previously,
+it used to be limited to one group of options only.
+
+=item chop()
+
+chop(@list) in list context returned the characters chopped in reverse
+order. This has been reversed to be in the right order.
+
+=item Unicode support
+
+Unicode support has seen a large number of incremental improvements,
+but continues to be highly experimental. It is not expected to be
+fully supported in the 5.6.x maintenance releases.
+
+substr(), join(), repeat(), reverse(), quotemeta() and string
+concatenation were all handling Unicode strings incorrectly in
+Perl 5.6.0. This has been corrected.
+
+Support for C<tr///CU> and C<tr///UC> etc., have been removed since
+we realized the interface is broken. For similar functionality,
+see L<perlfunc/pack>.
+
+The Unicode Character Database has been updated to version 3.0.1
+with additions made available to the public as of August 30, 2000.
+
+The Unicode character classes \p{Blank} and \p{SpacePerl} have been
+added. "Blank" is like C isblank(), that is, it contains only
+"horizontal whitespace" (the space character is, the newline isn't),
+and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
+isn't, since that includes the vertical tabulator character, whereas
+C<\s> doesn't.)
+
+If you are experimenting with Unicode support in perl, the development
+versions of Perl may have more to offer. In particular, I/O layers
+are now available in the development track, but not in the maintenance
+track, primarily to do backward compatibility issues. Unicode support
+is also evolving rapidly on a daily basis in the development track--the
+maintenance track only reflects the most conservative of these changes.
+
+=item 64-bit support
+
+Support for 64-bit platforms has been improved, but continues to be
+experimental. The level of support varies greatly among platforms.
+
+=item Compiler
+
+The B Compiler and its various backends have had many incremental
+improvements, but they continue to remain highly experimental. Use in
+production environments is discouraged.
+
+The perlcc tool has been rewritten so that the user interface is much
+more like that of a C compiler.
+
+The perlbc tools has been removed. Use C<perlcc -B> instead.
+
+=item Lvalue subroutines
+
+There have been various bugfixes to support lvalue subroutines better.
+However, the feature still remains experimental.
+
+=item IO::Socket
+
+IO::Socket::INET failed to open the specified port if the service
+name was not known. It now correctly uses the supplied port number
+as is.
+
+=item File::Find
+
+File::Find now chdir()s correctly when chasing symbolic links.
+
+=item xsubpp
+
+xsubpp now tolerates embedded POD sections.
+
+=item C<no Module;>
+
+C<no Module;> does not produce an error even if Module does not have an
+unimport() method. This parallels the behavior of C<use> vis-a-vis
+C<import>.
+
+=item Tests
+
+A large number of tests have been added.
+
+=back
+
+=head2 Core features
+
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details.
+
+The C<-DT> command line switch outputs copious tokenizing information.
+See L<perlrun>.
+
+Arrays are now always interpolated in double-quotish strings. Previously,
+C<"foo@bar.com"> used to be a fatal error at compile time, if an array
+C<@bar> was not used or declared. This transitional behavior was
+intended to help migrate perl4 code, and is deemed to be no longer useful.
+See L</"Arrays now always interpolate into double-quoted strings">.
+
+keys(), each(), pop(), push(), shift(), splice() and unshift()
+can all be overridden now.
+
+C<my __PACKAGE__ $obj> now does the expected thing.
+
+=head2 Configuration issues
+
+On some systems (IRIX and Solaris among them) the system malloc is demonstrably
+better. While the defaults haven't been changed in order to retain binary
+compatibility with earlier releases, you may be better off building perl
+with C<Configure -Uusemymalloc ...> as discussed in the F<INSTALL> file.
+
+C<Configure> has been enhanced in various ways:
+
+=over
+
+=item *
+
+Minimizes use of temporary files.
+
+=item *
+
+By default, does not link perl with libraries not used by it, such as
+the various dbm libraries. SunOS 4.x hints preserve behavior on that
+platform.
+
+=item *
+
+Support for pdp11-style memory models has been removed due to obsolescence.
+
+=item *
+
+Building outside the source tree is supported on systems that have
+symbolic links. This is done by running
+
+ sh /path/to/source/Configure -Dmksymlinks ...
+ make all test install
+
+in a directory other than the perl source directory. See F<INSTALL>.
+
+=item *
+
+C<Configure -S> can be run non-interactively.
+
+=back
+
+=head2 Documentation
+
+README.aix, README.solaris and README.macos have been added.
+README.posix-bc has been renamed to README.bs2000. These are
+installed as L<perlaix>, L<perlsolaris>, L<perlmacos>, and
+L<perlbs2000> respectively.
+
+The following pod documents are brand new:
+
+ perlclib Internal replacements for standard C library functions
+ perldebtut Perl debugging tutorial
+ perlebcdic Considerations for running Perl on EBCDIC platforms
+ perlnewmod Perl modules: preparing a new module for distribution
+ perlrequick Perl regular expressions quick start
+ perlretut Perl regular expressions tutorial
+ perlutil utilities packaged with the Perl distribution
+
+The F<INSTALL> file has been expanded to cover various issues, such as
+64-bit support.
+
+A longer list of contributors has been added to the source distribution.
+See the file C<AUTHORS>.
+
+Numerous other changes have been made to the included documentation and FAQs.
+
+=head2 Bundled modules
+
+The following modules have been added.
+
+=over
+
+=item B::Concise
+
+Walks Perl syntax tree, printing concise info about ops. See L<B::Concise>.
+
+=item File::Temp
+
+Returns name and handle of a temporary file safely. See L<File::Temp>.
+
+=item Pod::LaTeX
+
+Converts Pod data to formatted LaTeX. See L<Pod::LaTeX>.
+
+=item Pod::Text::Overstrike
+
+Converts POD data to formatted overstrike text. See L<Pod::Text::Overstrike>.
+
+=back
+
+The following modules have been upgraded.
+
+=over
+
+=item CGI
+
+CGI v2.752 is now included.
+
+=item CPAN
+
+CPAN v1.59_54 is now included.
+
+=item Class::Struct
+
+Various bugfixes have been added.
+
+=item DB_File
+
+DB_File v1.75 supports newer Berkeley DB versions, among other
+improvements.
+
+=item Devel::Peek
+
+Devel::Peek has been enhanced to support dumping of memory statistics,
+when perl is built with the included malloc().
+
+=item File::Find
+
+File::Find now supports pre and post-processing of the files in order
+to sort() them, etc.
+
+=item Getopt::Long
+
+Getopt::Long v2.25 is included.
+
+=item IO::Poll
+
+Various bug fixes have been included.
+
+=item IPC::Open3
+
+IPC::Open3 allows use of numeric file descriptors.
+
+=item Math::BigFloat
+
+The fmod() function supports modulus operations. Various bug fixes
+have also been included.
+
+=item Math::Complex
+
+Math::Complex handles inf, NaN etc., better.
+
+=item Net::Ping
+
+ping() could fail on odd number of data bytes, and when the echo service
+isn't running. This has been corrected.
+
+=item Opcode
+
+A memory leak has been fixed.
+
+=item Pod::Parser
+
+Version 1.13 of the Pod::Parser suite is included.
+
+=item Pod::Text
+
+Pod::Text and related modules have been upgraded to the versions
+in podlators suite v2.08.
+
+=item SDBM_File
+
+On dosish platforms, some keys went missing because of lack of support for
+files with "holes". A workaround for the problem has been added.
+
+=item Sys::Syslog
+
+Various bug fixes have been included.
+
+=item Tie::RefHash
+
+Now supports Tie::RefHash::Nestable to automagically tie hashref values.
+
+=item Tie::SubstrHash
+
+Various bug fixes have been included.
+
+=back
+
+=head2 Platform-specific improvements
+
+The following new ports are now available.
+
+=over
+
+=item NCR MP-RAS
+
+=item NonStop-UX
+
+=back
+
+Perl now builds under Amdahl UTS.
+
+Perl has also been verified to build under Amiga OS.
+
+Support for EPOC has been much improved. See README.epoc.
+
+Building perl with -Duseithreads or -Duse5005threads now works
+under HP-UX 10.20 (previously it only worked under 10.30 or later).
+You will need a thread library package installed. See README.hpux.
+
+Long doubles should now work under Linux.
+
+Mac OS Classic is now supported in the mainstream source package.
+See README.macos.
+
+Support for MPE/iX has been updated. See README.mpeix.
+
+Support for OS/2 has been improved. See C<os2/Changes> and README.os2.
+
+Dynamic loading on z/OS (formerly OS/390) has been improved. See
+README.os390.
+
+Support for VMS has seen many incremental improvements, including
+better support for operators like backticks and system(), and better
+%ENV handling. See C<README.vms> and L<perlvms>.
+
+Support for Stratus VOS has been improved. See C<vos/Changes> and README.vos.
+
+Support for Windows has been improved.
+
+=over
+
+=item *
+
+fork() emulation has been improved in various ways, but still continues
+to be experimental. See L<perlfork> for known bugs and caveats.
+
+=item *
+
+%SIG has been enabled under USE_ITHREADS, but its use is completely
+unsupported under all configurations.
+
+=item *
+
+Borland C++ v5.5 is now a supported compiler that can build Perl.
+However, the generated binaries continue to be incompatible with those
+generated by the other supported compilers (GCC and Visual C++).
+
+=item *
+
+Non-blocking waits for child processes (or pseudo-processes) are
+supported via C<waitpid($pid, &POSIX::WNOHANG)>.
+
+=item *
+
+A memory leak in accept() has been fixed.
+
+=item *
+
+wait(), waitpid() and backticks now return the correct exit status under
+Windows 9x.
+
+=item *
+
+Trailing new %ENV entries weren't propagated to child processes. This
+is now fixed.
+
+=item *
+
+Current directory entries in %ENV are now correctly propagated to child
+processes.
+
+=item *
+
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+
+=item *
+
+The makefiles now provide a single switch to bulk-enable all the features
+enabled in ActiveState ActivePerl (a popular binary distribution).
+
+=item *
+
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed.
+
+=item *
+
+fork() correctly returns undef and sets EAGAIN when it runs out of
+pseudo-process handles.
+
+=item *
+
+ExtUtils::MakeMaker now uses $ENV{LIB} to search for libraries.
+
+=item *
+
+UNC path handling is better when perl is built to support fork().
+
+=item *
+
+A handle leak in socket handling has been fixed.
+
+=item *
+
+send() works from within a pseudo-process.
+
+=back
+
+Unless specifically qualified otherwise, the remainder of this document
+covers changes between the 5.005 and 5.6.0 releases.
+
+=head1 Core Enhancements
+
+=head2 Interpreter cloning, threads, and concurrency
+
+Perl 5.6.0 introduces the beginnings of support for running multiple
+interpreters concurrently in different threads. In conjunction with
+the perl_clone() API call, which can be used to selectively duplicate
+the state of any given interpreter, it is possible to compile a
+piece of code once in an interpreter, clone that interpreter
+one or more times, and run all the resulting interpreters in distinct
+threads.
+
+On the Windows platform, this feature is used to emulate fork() at the
+interpreter level. See L<perlfork> for details about that.
+
+This feature is still in evolution. It is eventually meant to be used
+to selectively clone a subroutine and data reachable from that
+subroutine in a separate interpreter and run the cloned subroutine
+in a separate thread. Since there is no shared data between the
+interpreters, little or no locking will be needed (unless parts of
+the symbol table are explicitly shared). This is obviously intended
+to be an easy-to-use replacement for the existing threads support.
+
+Support for cloning interpreters and interpreter concurrency can be
+enabled using the -Dusethreads Configure option (see win32/Makefile for
+how to enable it on Windows.) The resulting perl executable will be
+functionally identical to one that was built with -Dmultiplicity, but
+the perl_clone() API call will only be available in the former.
+
+-Dusethreads enables the cpp macro USE_ITHREADS by default, which in turn
+enables Perl source code changes that provide a clear separation between
+the op tree and the data it operates with. The former is immutable, and
+can therefore be shared between an interpreter and all of its clones,
+while the latter is considered local to each interpreter, and is therefore
+copied for each clone.
+
+Note that building Perl with the -Dusemultiplicity Configure option
+is adequate if you wish to run multiple B<independent> interpreters
+concurrently in different threads. -Dusethreads only provides the
+additional functionality of the perl_clone() API call and other
+support for running B<cloned> interpreters concurrently.
+
+ NOTE: This is an experimental feature. Implementation details are
+ subject to change.
+
+=head2 Lexically scoped warning categories
+
+You can now control the granularity of warnings emitted by perl at a finer
+level using the C<use warnings> pragma. L<warnings> and L<perllexwarn>
+have copious documentation on this feature.
+
+=head2 Unicode and UTF-8 support
+
+Perl now uses UTF-8 as its internal representation for character
+strings. The C<utf8> and C<bytes> pragmas are used to control this support
+in the current lexical scope. See L<perlunicode>, L<utf8> and L<bytes> for
+more information.
+
+This feature is expected to evolve quickly to support some form of I/O
+disciplines that can be used to specify the kind of input and output data
+(bytes or characters). Until that happens, additional modules from CPAN
+will be needed to complete the toolkit for dealing with Unicode.
+
+ NOTE: This should be considered an experimental feature. Implementation
+ details are subject to change.
+
+=head2 Support for interpolating named characters
+
+The new C<\N> escape interpolates named characters within strings.
+For example, C<"Hi! \N{WHITE SMILING FACE}"> evaluates to a string
+with a Unicode smiley face at the end.
+
+=head2 "our" declarations
+
+An "our" declaration introduces a value that can be best understood
+as a lexically scoped symbolic alias to a global variable in the
+package that was current where the variable was declared. This is
+mostly useful as an alternative to the C<vars> pragma, but also provides
+the opportunity to introduce typing and other attributes for such
+variables. See L<perlfunc/our>.
+
+=head2 Support for strings represented as a vector of ordinals
+
+Literals of the form C<v1.2.3.4> are now parsed as a string composed
+of characters with the specified ordinals. This is an alternative, more
+readable way to construct (possibly Unicode) strings instead of
+interpolating characters, as in C<"\x{1}\x{2}\x{3}\x{4}">. The leading
+C<v> may be omitted if there are more than two ordinals, so C<1.2.3> is
+parsed the same as C<v1.2.3>.
+
+Strings written in this form are also useful to represent version "numbers".
+It is easy to compare such version "numbers" (which are really just plain
+strings) using any of the usual string comparison operators C<eq>, C<ne>,
+C<lt>, C<gt>, etc., or perform bitwise string operations on them using C<|>,
+C<&>, etc.
+
+In conjunction with the new C<$^V> magic variable (which contains
+the perl version as a string), such literals can be used as a readable way
+to check if you're running a particular version of Perl:
+
+ # this will parse in older versions of Perl also
+ if ($^V and $^V gt v5.6.0) {
+ # new features supported
+ }
+
+C<require> and C<use> also have some special magic to support such literals.
+They will be interpreted as a version rather than as a module name:
+
+ require v5.6.0; # croak if $^V lt v5.6.0
+ use v5.6.0; # same, but croaks at compile-time
+
+Alternatively, the C<v> may be omitted if there is more than one dot:
+
+ require 5.6.0;
+ use 5.6.0;
+
+Also, C<sprintf> and C<printf> support the Perl-specific format flag C<%v>
+to print ordinals of characters in arbitrary strings:
+
+ printf "v%vd", $^V; # prints current version, such as "v5.5.650"
+ printf "%*vX", ":", $addr; # formats IPv6 address
+ printf "%*vb", " ", $bits; # displays bitstring
+
+See L<perldata/"Scalar value constructors"> for additional information.
+
+=head2 Improved Perl version numbering system
+
+Beginning with Perl version 5.6.0, the version number convention has been
+changed to a "dotted integer" scheme that is more commonly found in open
+source projects.
+
+Maintenance versions of v5.6.0 will be released as v5.6.1, v5.6.2 etc.
+The next development series following v5.6.0 will be numbered v5.7.x,
+beginning with v5.7.0, and the next major production release following
+v5.6.0 will be v5.8.0.
+
+The English module now sets $PERL_VERSION to $^V (a string value) rather
+than C<$]> (a numeric value). (This is a potential incompatibility.
+Send us a report via perlbug if you are affected by this.)
+
+The v1.2.3 syntax is also now legal in Perl.
+See L<Support for strings represented as a vector of ordinals> for more on that.
+
+To cope with the new versioning system's use of at least three significant
+digits for each version component, the method used for incrementing the
+subversion number has also changed slightly. We assume that versions older
+than v5.6.0 have been incrementing the subversion component in multiples of
+10. Versions after v5.6.0 will increment them by 1. Thus, using the new
+notation, 5.005_03 is the "same" as v5.5.30, and the first maintenance
+version following v5.6.0 will be v5.6.1 (which should be read as being
+equivalent to a floating point value of 5.006_001 in the older format,
+stored in C<$]>).
+
+=head2 New syntax for declaring subroutine attributes
+
+Formerly, if you wanted to mark a subroutine as being a method call or
+as requiring an automatic lock() when it is entered, you had to declare
+that with a C<use attrs> pragma in the body of the subroutine.
+That can now be accomplished with declaration syntax, like this:
+
+ sub mymethod : locked method;
+ ...
+ sub mymethod : locked method {
+ ...
+ }
+
+ sub othermethod :locked :method;
+ ...
+ sub othermethod :locked :method {
+ ...
+ }
+
+
+(Note how only the first C<:> is mandatory, and whitespace surrounding
+the C<:> is optional.)
+
+F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes
+with the stubs they provide. See L<attributes>.
+
+=head2 File and directory handles can be autovivified
+
+Similar to how constructs such as C<< $x->[0] >> autovivify a reference,
+handle constructors (open(), opendir(), pipe(), socketpair(), sysopen(),
+socket(), and accept()) now autovivify a file or directory handle
+if the handle passed to them is an uninitialized scalar variable. This
+allows the constructs such as C<open(my $fh, ...)> and C<open(local $fh,...)>
+to be used to create filehandles that will conveniently be closed
+automatically when the scope ends, provided there are no other references
+to them. This largely eliminates the need for typeglobs when opening
+filehandles that must be passed around, as in the following example:
+
+ sub myopen {
+ open my $fh, "@_"
+ or die "Can't open '@_': $!";
+ return $fh;
+ }
+
+ {
+ my $f = myopen("</etc/motd");
+ print <$f>;
+ # $f implicitly closed here
+ }
+
+=head2 open() with more than two arguments
+
+If open() is passed three arguments instead of two, the second argument
+is used as the mode and the third argument is taken to be the file name.
+This is primarily useful for protecting against unintended magic behavior
+of the traditional two-argument form. See L<perlfunc/open>.
+
+=head2 64-bit support
+
+Any platform that has 64-bit integers either
+
+ (1) natively as longs or ints
+ (2) via special compiler flags
+ (3) using long long or int64_t
+
+is able to use "quads" (64-bit integers) as follows:
+
+=over 4
+
+=item *
+
+constants (decimal, hexadecimal, octal, binary) in the code
+
+=item *
+
+arguments to oct() and hex()
+
+=item *
+
+arguments to print(), printf() and sprintf() (flag prefixes ll, L, q)
+
+=item *
+
+printed as such
+
+=item *
+
+pack() and unpack() "q" and "Q" formats
+
+=item *
+
+in basic arithmetics: + - * / % (NOTE: operating close to the limits
+of the integer values may produce surprising results)
+
+=item *
+
+in bit arithmetics: & | ^ ~ << >> (NOTE: these used to be forced
+to be 32 bits wide but now operate on the full native width.)
+
+=item *
+
+vec()
+
+=back
+
+Note that unless you have the case (a) you will have to configure
+and compile Perl using the -Duse64bitint Configure flag.
+
+ NOTE: The Configure flags -Duselonglong and -Duse64bits have been
+ deprecated. Use -Duse64bitint instead.
+
+There are actually two modes of 64-bitness: the first one is achieved
+using Configure -Duse64bitint and the second one using Configure
+-Duse64bitall. The difference is that the first one is minimal and
+the second one maximal. The first works in more places than the second.
+
+The C<use64bitint> does only as much as is required to get 64-bit
+integers into Perl (this may mean, for example, using "long longs")
+while your memory may still be limited to 2 gigabytes (because your
+pointers could still be 32-bit). Note that the name C<64bitint> does
+not imply that your C compiler will be using 64-bit C<int>s (it might,
+but it doesn't have to): the C<use64bitint> means that you will be
+able to have 64 bits wide scalar values.
+
+The C<use64bitall> goes all the way by attempting to switch also
+integers (if it can), longs (and pointers) to being 64-bit. This may
+create an even more binary incompatible Perl than -Duse64bitint: the
+resulting executable may not run at all in a 32-bit box, or you may
+have to reboot/reconfigure/rebuild your operating system to be 64-bit
+aware.
+
+Natively 64-bit systems like Alpha and Cray need neither -Duse64bitint
+nor -Duse64bitall.
+
+Last but not least: note that due to Perl's habit of always using
+floating point numbers, the quads are still not true integers.
+When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned,
+-9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they
+are silently promoted to floating point numbers, after which they will
+start losing precision (in their lower digits).
+
+ NOTE: 64-bit support is still experimental on most platforms.
+ Existing support only covers the LP64 data model. In particular, the
+ LLP64 data model is not yet supported. 64-bit libraries and system
+ APIs on many platforms have not stabilized--your mileage may vary.
+
+=head2 Large file support
+
+If you have filesystems that support "large files" (files larger than
+2 gigabytes), you may now also be able to create and access them from
+Perl.
+
+ NOTE: The default action is to enable large file support, if
+ available on the platform.
+
+If the large file support is on, and you have a Fcntl constant
+O_LARGEFILE, the O_LARGEFILE is automatically added to the flags
+of sysopen().
+
+Beware that unless your filesystem also supports "sparse files" seeking
+to umpteen petabytes may be inadvisable.
+
+Note that in addition to requiring a proper file system to do large
+files you may also need to adjust your per-process (or your
+per-system, or per-process-group, or per-user-group) maximum filesize
+limits before running Perl scripts that try to handle large files,
+especially if you intend to write such files.
+
+Finally, in addition to your process/process group maximum filesize
+limits, you may have quota limits on your filesystems that stop you
+(your user id or your user group id) from using large files.
+
+Adjusting your process/user/group/file system/operating system limits
+is outside the scope of Perl core language. For process limits, you
+may try increasing the limits using your shell's limits/limit/ulimit
+command before running Perl. The BSD::Resource extension (not
+included with the standard Perl distribution) may also be of use, it
+offers the getrlimit/setrlimit interface that can be used to adjust
+process resource usage limits, including the maximum filesize limit.
+
+=head2 Long doubles
+
+In some systems you may be able to use long doubles to enhance the
+range and precision of your double precision floating point numbers
+(that is, Perl's numbers). Use Configure -Duselongdouble to enable
+this support (if it is available).
+
+=head2 "more bits"
+
+You can "Configure -Dusemorebits" to turn on both the 64-bit support
+and the long double support.
+
+=head2 Enhanced support for sort() subroutines
+
+Perl subroutines with a prototype of C<($$)>, and XSUBs in general, can
+now be used as sort subroutines. In either case, the two elements to
+be compared are passed as normal parameters in @_. See L<perlfunc/sort>.
+
+For unprototyped sort subroutines, the historical behavior of passing
+the elements to be compared as the global variables $a and $b remains
+unchanged.
+
+=head2 C<sort $coderef @foo> allowed
+
+sort() did not accept a subroutine reference as the comparison
+function in earlier versions. This is now permitted.
+
+=head2 File globbing implemented internally
+
+Perl now uses the File::Glob implementation of the glob() operator
+automatically. This avoids using an external csh process and the
+problems associated with it.
+
+ NOTE: This is currently an experimental feature. Interfaces and
+ implementation are subject to change.
+
+=head2 Support for CHECK blocks
+
+In addition to C<BEGIN>, C<INIT>, C<END>, C<DESTROY> and C<AUTOLOAD>,
+subroutines named C<CHECK> are now special. These are queued up during
+compilation and behave similar to END blocks, except they are called at
+the end of compilation rather than at the end of execution. They cannot
+be called directly.
+
+=head2 POSIX character class syntax [: :] supported
+
+For example to match alphabetic characters use /[[:alpha:]]/.
+See L<perlre> for details.
+
+=head2 Better pseudo-random number generator
+
+In 5.005_0x and earlier, perl's rand() function used the C library
+rand(3) function. As of 5.005_52, Configure tests for drand48(),
+random(), and rand() (in that order) and picks the first one it finds.
+
+These changes should result in better random numbers from rand().
+
+=head2 Improved C<qw//> operator
+
+The C<qw//> operator is now evaluated at compile time into a true list
+instead of being replaced with a run time call to C<split()>. This
+removes the confusing misbehaviour of C<qw//> in scalar context, which
+had inherited that behaviour from split().
+
+Thus:
+
+ $foo = ($bar) = qw(a b c); print "$foo|$bar\n";
+
+now correctly prints "3|a", instead of "2|a".
+
+=head2 Better worst-case behavior of hashes
+
+Small changes in the hashing algorithm have been implemented in
+order to improve the distribution of lower order bits in the
+hashed value. This is expected to yield better performance on
+keys that are repeated sequences.
+
+=head2 pack() format 'Z' supported
+
+The new format type 'Z' is useful for packing and unpacking null-terminated
+strings. See L<perlfunc/"pack">.
+
+=head2 pack() format modifier '!' supported
+
+The new format type modifier '!' is useful for packing and unpacking
+native shorts, ints, and longs. See L<perlfunc/"pack">.
+
+=head2 pack() and unpack() support counted strings
+
+The template character '/' can be used to specify a counted string
+type to be packed or unpacked. See L<perlfunc/"pack">.
+
+=head2 Comments in pack() templates
+
+The '#' character in a template introduces a comment up to
+end of the line. This facilitates documentation of pack()
+templates.
+
+=head2 Weak references
+
+In previous versions of Perl, you couldn't cache objects so as
+to allow them to be deleted if the last reference from outside
+the cache is deleted. The reference in the cache would hold a
+reference count on the object and the objects would never be
+destroyed.
+
+Another familiar problem is with circular references. When an
+object references itself, its reference count would never go
+down to zero, and it would not get destroyed until the program
+is about to exit.
+
+Weak references solve this by allowing you to "weaken" any
+reference, that is, make it not count towards the reference count.
+When the last non-weak reference to an object is deleted, the object
+is destroyed and all the weak references to the object are
+automatically undef-ed.
+
+To use this feature, you need the Devel::WeakRef package from CPAN, which
+contains additional documentation.
+
+ NOTE: This is an experimental feature. Details are subject to change.
+
+=head2 Binary numbers supported
+
+Binary numbers are now supported as literals, in s?printf formats, and
+C<oct()>:
+
+ $answer = 0b101010;
+ printf "The answer is: %b\n", oct("0b101010");
+
+=head2 Lvalue subroutines
+
+Subroutines can now return modifiable lvalues.
+See L<perlsub/"Lvalue subroutines">.
+
+ NOTE: This is an experimental feature. Details are subject to change.
+
+=head2 Some arrows may be omitted in calls through references
+
+Perl now allows the arrow to be omitted in many constructs
+involving subroutine calls through references. For example,
+C<< $foo[10]->('foo') >> may now be written C<$foo[10]('foo')>.
+This is rather similar to how the arrow may be omitted from
+C<< $foo[10]->{'foo'} >>. Note however, that the arrow is still
+required for C<< foo(10)->('bar') >>.
+
+=head2 Boolean assignment operators are legal lvalues
+
+Constructs such as C<($a ||= 2) += 1> are now allowed.
+
+=head2 exists() is supported on subroutine names
+
+The exists() builtin now works on subroutine names. A subroutine
+is considered to exist if it has been declared (even if implicitly).
+See L<perlfunc/exists> for examples.
+
+=head2 exists() and delete() are supported on array elements
+
+The exists() and delete() builtins now work on simple arrays as well.
+The behavior is similar to that on hash elements.
+
+exists() can be used to check whether an array element has been
+initialized. This avoids autovivifying array elements that don't exist.
+If the array is tied, the EXISTS() method in the corresponding tied
+package will be invoked.
+
+delete() may be used to remove an element from the array and return
+it. The array element at that position returns to its uninitialized
+state, so that testing for the same element with exists() will return
+false. If the element happens to be the one at the end, the size of
+the array also shrinks up to the highest element that tests true for
+exists(), or 0 if none such is found. If the array is tied, the DELETE()
+method in the corresponding tied package will be invoked.
+
+See L<perlfunc/exists> and L<perlfunc/delete> for examples.
+
+=head2 Pseudo-hashes work better
+
+Dereferencing some types of reference values in a pseudo-hash,
+such as C<< $ph->{foo}[1] >>, was accidentally disallowed. This has
+been corrected.
+
+When applied to a pseudo-hash element, exists() now reports whether
+the specified value exists, not merely if the key is valid.
+
+delete() now works on pseudo-hashes. When given a pseudo-hash element
+or slice it deletes the values corresponding to the keys (but not the keys
+themselves). See L<perlref/"Pseudo-hashes: Using an array as a hash">.
+
+Pseudo-hash slices with constant keys are now optimized to array lookups
+at compile-time.
+
+List assignments to pseudo-hash slices are now supported.
+
+The C<fields> pragma now provides ways to create pseudo-hashes, via
+fields::new() and fields::phash(). See L<fields>.
+
+ NOTE: The pseudo-hash data type continues to be experimental.
+ Limiting oneself to the interface elements provided by the
+ fields pragma will provide protection from any future changes.
+
+=head2 Automatic flushing of output buffers
+
+fork(), exec(), system(), qx//, and pipe open()s now flush buffers
+of all files opened for output when the operation was attempted. This
+mostly eliminates confusing buffering mishaps suffered by users unaware
+of how Perl internally handles I/O.
+
+This is not supported on some platforms like Solaris where a suitably
+correct implementation of fflush(NULL) isn't available.
+
+=head2 Better diagnostics on meaningless filehandle operations
+
+Constructs such as C<< open(<FH>) >> and C<< close(<FH>) >>
+are compile time errors. Attempting to read from filehandles that
+were opened only for writing will now produce warnings (just as
+writing to read-only filehandles does).
+
+=head2 Where possible, buffered data discarded from duped input filehandle
+
+C<< open(NEW, "<&OLD") >> now attempts to discard any data that
+was previously read and buffered in C<OLD> before duping the handle.
+On platforms where doing this is allowed, the next read operation
+on C<NEW> will return the same data as the corresponding operation
+on C<OLD>. Formerly, it would have returned the data from the start
+of the following disk block instead.
+
+=head2 eof() has the same old magic as <>
+
+C<eof()> would return true if no attempt to read from C<< <> >> had
+yet been made. C<eof()> has been changed to have a little magic of its
+own, it now opens the C<< <> >> files.
+
+=head2 binmode() can be used to set :crlf and :raw modes
+
+binmode() now accepts a second argument that specifies a discipline
+for the handle in question. The two pseudo-disciplines ":raw" and
+":crlf" are currently supported on DOS-derivative platforms.
+See L<perlfunc/"binmode"> and L<open>.
+
+=head2 C<-T> filetest recognizes UTF-8 encoded files as "text"
+
+The algorithm used for the C<-T> filetest has been enhanced to
+correctly identify UTF-8 content as "text".
+
+=head2 system(), backticks and pipe open now reflect exec() failure
+
+On Unix and similar platforms, system(), qx() and open(FOO, "cmd |")
+etc., are implemented via fork() and exec(). When the underlying
+exec() fails, earlier versions did not report the error properly,
+since the exec() happened to be in a different process.
+
+The child process now communicates with the parent about the
+error in launching the external command, which allows these
+constructs to return with their usual error value and set $!.
+
+=head2 Improved diagnostics
+
+Line numbers are no longer suppressed (under most likely circumstances)
+during the global destruction phase.
+
+Diagnostics emitted from code running in threads other than the main
+thread are now accompanied by the thread ID.
+
+Embedded null characters in diagnostics now actually show up. They
+used to truncate the message in prior versions.
+
+$foo::a and $foo::b are now exempt from "possible typo" warnings only
+if sort() is encountered in package C<foo>.
+
+Unrecognized alphabetic escapes encountered when parsing quote
+constructs now generate a warning, since they may take on new
+semantics in later versions of Perl.
+
+Many diagnostics now report the internal operation in which the warning
+was provoked, like so:
+
+ Use of uninitialized value in concatenation (.) at (eval 1) line 1.
+ Use of uninitialized value in print at (eval 1) line 1.
+
+Diagnostics that occur within eval may also report the file and line
+number where the eval is located, in addition to the eval sequence
+number and the line number within the evaluated text itself. For
+example:
+
+ Not enough arguments for scalar at (eval 4)[newlib/perl5db.pl:1411] line 2, at EOF
+
+=head2 Diagnostics follow STDERR
+
+Diagnostic output now goes to whichever file the C<STDERR> handle
+is pointing at, instead of always going to the underlying C runtime
+library's C<stderr>.
+
+=head2 More consistent close-on-exec behavior
+
+On systems that support a close-on-exec flag on filehandles, the
+flag is now set for any handles created by pipe(), socketpair(),
+socket(), and accept(), if that is warranted by the value of $^F
+that may be in effect. Earlier versions neglected to set the flag
+for handles created with these operators. See L<perlfunc/pipe>,
+L<perlfunc/socketpair>, L<perlfunc/socket>, L<perlfunc/accept>,
+and L<perlvar/$^F>.
+
+=head2 syswrite() ease-of-use
+
+The length argument of C<syswrite()> has become optional.
+
+=head2 Better syntax checks on parenthesized unary operators
+
+Expressions such as:
+
+ print defined(&foo,&bar,&baz);
+ print uc("foo","bar","baz");
+ undef($foo,&bar);
+
+used to be accidentally allowed in earlier versions, and produced
+unpredictable behaviour. Some produced ancillary warnings
+when used in this way; others silently did the wrong thing.
+
+The parenthesized forms of most unary operators that expect a single
+argument now ensure that they are not called with more than one
+argument, making the cases shown above syntax errors. The usual
+behaviour of:
+
+ print defined &foo, &bar, &baz;
+ print uc "foo", "bar", "baz";
+ undef $foo, &bar;
+
+remains unchanged. See L<perlop>.
+
+=head2 Bit operators support full native integer width
+
+The bit operators (& | ^ ~ << >>) now operate on the full native
+integral width (the exact size of which is available in $Config{ivsize}).
+For example, if your platform is either natively 64-bit or if Perl
+has been configured to use 64-bit integers, these operations apply
+to 8 bytes (as opposed to 4 bytes on 32-bit platforms).
+For portability, be sure to mask off the excess bits in the result of
+unary C<~>, e.g., C<~$x & 0xffffffff>.
+
+=head2 Improved security features
+
+More potentially unsafe operations taint their results for improved
+security.
+
+The C<passwd> and C<shell> fields returned by the getpwent(), getpwnam(),
+and getpwuid() are now tainted, because the user can affect their own
+encrypted password and login shell.
+
+The variable modified by shmread(), and messages returned by msgrcv()
+(and its object-oriented interface IPC::SysV::Msg::rcv) are also tainted,
+because other untrusted processes can modify messages and shared memory
+segments for their own nefarious purposes.
+
+=head2 More functional bareword prototype (*)
+
+Bareword prototypes have been rationalized to enable them to be used
+to override builtins that accept barewords and interpret them in
+a special way, such as C<require> or C<do>.
+
+Arguments prototyped as C<*> will now be visible within the subroutine
+as either a simple scalar or as a reference to a typeglob.
+See L<perlsub/Prototypes>.
+
+=head2 C<require> and C<do> may be overridden
+
+C<require> and C<do 'file'> operations may be overridden locally
+by importing subroutines of the same name into the current package
+(or globally by importing them into the CORE::GLOBAL:: namespace).
+Overriding C<require> will also affect C<use>, provided the override
+is visible at compile-time.
+See L<perlsub/"Overriding Built-in Functions">.
+
+=head2 $^X variables may now have names longer than one character
+
+Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax
+error. Now variable names that begin with a control character may be
+arbitrarily long. However, for compatibility reasons, these variables
+I<must> be written with explicit braces, as C<${^XY}> for example.
+C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more
+than one control character, such as C<${^XY^Z}>, are illegal.
+
+The old syntax has not changed. As before, `^X' may be either a
+literal control-X character or the two-character sequence `caret' plus
+`X'. When braces are omitted, the variable name stops after the
+control character. Thus C<"$^XYZ"> continues to be synonymous with
+C<$^X . "YZ"> as before.
+
+As before, lexical variables may not have names beginning with control
+characters. As before, variables whose names begin with a control
+character are always forced to be in package `main'. All such variables
+are reserved for future extensions, except those that begin with
+C<^_>, which may be used by user programs and are guaranteed not to
+acquire special meaning in any future version of Perl.
+
+=head2 New variable $^C reflects C<-c> switch
+
+C<$^C> has a boolean value that reflects whether perl is being run
+in compile-only mode (i.e. via the C<-c> switch). Since
+BEGIN blocks are executed under such conditions, this variable
+enables perl code to determine whether actions that make sense
+only during normal running are warranted. See L<perlvar>.
+
+=head2 New variable $^V contains Perl version as a string
+
+C<$^V> contains the Perl version number as a string composed of
+characters whose ordinals match the version numbers, i.e. v5.6.0.
+This may be used in string comparisons.
+
+See C<Support for strings represented as a vector of ordinals> for an
+example.
+
+=head2 Optional Y2K warnings
+
+If Perl is built with the cpp macro C<PERL_Y2KWARN> defined,
+it emits optional warnings when concatenating the number 19
+with another number.
+
+This behavior must be specifically enabled when running Configure.
+See F<INSTALL> and F<README.Y2K>.
+
+=head2 Arrays now always interpolate into double-quoted strings
+
+In double-quoted strings, arrays now interpolate, no matter what. The
+behavior in earlier versions of perl 5 was that arrays would interpolate
+into strings if the array had been mentioned before the string was
+compiled, and otherwise Perl would raise a fatal compile-time error.
+In versions 5.000 through 5.003, the error was
+
+ Literal @example now requires backslash
+
+In versions 5.004_01 through 5.6.0, the error was
+
+ In string, @example now must be written as \@example
+
+The idea here was to get people into the habit of writing
+C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
+they have always written C<"Give me back my \$5"> when they wanted a
+literal C<$> sign.
+
+Starting with 5.6.1, when Perl now sees an C<@> sign in a
+double-quoted string, it I<always> attempts to interpolate an array,
+regardless of whether or not the array has been used or declared
+already. The fatal error has been downgraded to an optional warning:
+
+ Possible unintended interpolation of @example in string
+
+This warns you that C<"fred@example.com"> is going to turn into
+C<fred.com> if you don't backslash the C<@>.
+See http://perl.plover.com/at-error.html for more details
+about the history here.
+
+=head2 @- and @+ provide starting/ending offsets of regex submatches
+
+The new magic variables @- and @+ provide the starting and ending
+offsets, respectively, of $&, $1, $2, etc. See L<perlvar> for
+details.
+
+=head1 Modules and Pragmata
+
+=head2 Modules
+
+=over 4
+
+=item attributes
+
+While used internally by Perl as a pragma, this module also
+provides a way to fetch subroutine and variable attributes.
+See L<attributes>.
+
+=item B
+
+The Perl Compiler suite has been extensively reworked for this
+release. More of the standard Perl test suite passes when run
+under the Compiler, but there is still a significant way to
+go to achieve production quality compiled executables.
+
+ NOTE: The Compiler suite remains highly experimental. The
+ generated code may not be correct, even when it manages to execute
+ without errors.
+
+=item Benchmark
+
+Overall, Benchmark results exhibit lower average error and better timing
+accuracy.
+
+You can now run tests for I<n> seconds instead of guessing the right
+number of tests to run: e.g., timethese(-5, ...) will run each
+code for at least 5 CPU seconds. Zero as the "number of repetitions"
+means "for at least 3 CPU seconds". The output format has also
+changed. For example:
+
+ use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
+
+will now output something like this:
+
+ Benchmark: running a, b, each for at least 5 CPU seconds...
+ a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
+ b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
+
+New features: "each for at least N CPU seconds...", "wallclock secs",
+and the "@ operations/CPU second (n=operations)".
+
+timethese() now returns a reference to a hash of Benchmark objects containing
+the test results, keyed on the names of the tests.
+
+timethis() now returns the iterations field in the Benchmark result object
+instead of 0.
+
+timethese(), timethis(), and the new cmpthese() (see below) can also take
+a format specifier of 'none' to suppress output.
+
+A new function countit() is just like timeit() except that it takes a
+TIME instead of a COUNT.
+
+A new function cmpthese() prints a chart comparing the results of each test
+returned from a timethese() call. For each possible pair of tests, the
+percentage speed difference (iters/sec or seconds/iter) is shown.
+
+For other details, see L<Benchmark>.
+
+=item ByteLoader
+
+The ByteLoader is a dedicated extension to generate and run
+Perl bytecode. See L<ByteLoader>.
+
+=item constant
+
+References can now be used.
+
+The new version also allows a leading underscore in constant names, but
+disallows a double leading underscore (as in "__LINE__"). Some other names
+are disallowed or warned against, including BEGIN, END, etc. Some names
+which were forced into main:: used to fail silently in some cases; now they're
+fatal (outside of main::) and an optional warning (inside of main::).
+The ability to detect whether a constant had been set with a given name has
+been added.
+
+See L<constant>.
+
+=item charnames
+
+This pragma implements the C<\N> string escape. See L<charnames>.
+
+=item Data::Dumper
+
+A C<Maxdepth> setting can be specified to avoid venturing
+too deeply into deep data structures. See L<Data::Dumper>.
+
+The XSUB implementation of Dump() is now automatically called if the
+C<Useqq> setting is not in use.
+
+Dumping C<qr//> objects works correctly.
+
+=item DB
+
+C<DB> is an experimental module that exposes a clean abstraction
+to Perl's debugging API.
+
+=item DB_File
+
+DB_File can now be built with Berkeley DB versions 1, 2 or 3.
+See C<ext/DB_File/Changes>.
+
+=item Devel::DProf
+
+Devel::DProf, a Perl source code profiler has been added. See
+L<Devel::DProf> and L<dprofpp>.
+
+=item Devel::Peek
+
+The Devel::Peek module provides access to the internal representation
+of Perl variables and data. It is a data debugging tool for the XS programmer.
+
+=item Dumpvalue
+
+The Dumpvalue module provides screen dumps of Perl data.
+
+=item DynaLoader
+
+DynaLoader now supports a dl_unload_file() function on platforms that
+support unloading shared objects using dlclose().
+
+Perl can also optionally arrange to unload all extension shared objects
+loaded by Perl. To enable this, build Perl with the Configure option
+C<-Accflags=-DDL_UNLOAD_ALL_AT_EXIT>. (This maybe useful if you are
+using Apache with mod_perl.)
+
+=item English
+
+$PERL_VERSION now stands for C<$^V> (a string value) rather than for C<$]>
+(a numeric value).
+
+=item Env
+
+Env now supports accessing environment variables like PATH as array
+variables.
+
+=item Fcntl
+
+More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
+large file (more than 4GB) access (NOTE: the O_LARGEFILE is
+automatically added to sysopen() flags if large file support has been
+configured, as is the default), Free/Net/OpenBSD locking behaviour
+flags F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the combined
+mask of O_RDONLY, O_WRONLY, and O_RDWR. The seek()/sysseek()
+constants SEEK_SET, SEEK_CUR, and SEEK_END are available via the
+C<:seek> tag. The chmod()/stat() S_IF* constants and S_IS* functions
+are available via the C<:mode> tag.
+
+=item File::Compare
+
+A compare_text() function has been added, which allows custom
+comparison functions. See L<File::Compare>.
+
+=item File::Find
+
+File::Find now works correctly when the wanted() function is either
+autoloaded or is a symbolic reference.
+
+A bug that caused File::Find to lose track of the working directory
+when pruning top-level directories has been fixed.
+
+File::Find now also supports several other options to control its
+behavior. It can follow symbolic links if the C<follow> option is
+specified. Enabling the C<no_chdir> option will make File::Find skip
+changing the current directory when walking directories. The C<untaint>
+flag can be useful when running with taint checks enabled.
+
+See L<File::Find>.
+
+=item File::Glob
+
+This extension implements BSD-style file globbing. By default,
+it will also be used for the internal implementation of the glob()
+operator. See L<File::Glob>.
+
+=item File::Spec
+
+New methods have been added to the File::Spec module: devnull() returns
+the name of the null device (/dev/null on Unix) and tmpdir() the name of
+the temp directory (normally /tmp on Unix). There are now also methods
+to convert between absolute and relative filenames: abs2rel() and
+rel2abs(). For compatibility with operating systems that specify volume
+names in file paths, the splitpath(), splitdir(), and catdir() methods
+have been added.
+
+=item File::Spec::Functions
+
+The new File::Spec::Functions modules provides a function interface
+to the File::Spec module. Allows shorthand
+
+ $fullname = catfile($dir1, $dir2, $file);
+
+instead of
+
+ $fullname = File::Spec->catfile($dir1, $dir2, $file);
+
+=item Getopt::Long
+
+Getopt::Long licensing has changed to allow the Perl Artistic License
+as well as the GPL. It used to be GPL only, which got in the way of
+non-GPL applications that wanted to use Getopt::Long.
+
+Getopt::Long encourages the use of Pod::Usage to produce help
+messages. For example:
+
+ use Getopt::Long;
+ use Pod::Usage;
+ my $man = 0;
+ my $help = 0;
+ GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
+ pod2usage(1) if $help;
+ pod2usage(-exitstatus => 0, -verbose => 2) if $man;
+
+ __END__
+
+ =head1 NAME
+
+ sample - Using Getopt::Long and Pod::Usage
+
+ =head1 SYNOPSIS
+
+ sample [options] [file ...]
+
+ Options:
+ -help brief help message
+ -man full documentation
+
+ =head1 OPTIONS
+
+ =over 8
+
+ =item B<-help>
+
+ Print a brief help message and exits.
+
+ =item B<-man>
+
+ Prints the manual page and exits.
+
+ =back
+
+ =head1 DESCRIPTION
+
+ B<This program> will read the given input file(s) and do something
+ useful with the contents thereof.
+
+ =cut
+
+See L<Pod::Usage> for details.
+
+A bug that prevented the non-option call-back <> from being
+specified as the first argument has been fixed.
+
+To specify the characters < and > as option starters, use ><. Note,
+however, that changing option starters is strongly deprecated.
+
+=item IO
+
+write() and syswrite() will now accept a single-argument
+form of the call, for consistency with Perl's syswrite().
+
+You can now create a TCP-based IO::Socket::INET without forcing
+a connect attempt. This allows you to configure its options
+(like making it non-blocking) and then call connect() manually.
+
+A bug that prevented the IO::Socket::protocol() accessor
+from ever returning the correct value has been corrected.
+
+IO::Socket::connect now uses non-blocking IO instead of alarm()
+to do connect timeouts.
+
+IO::Socket::accept now uses select() instead of alarm() for doing
+timeouts.
+
+IO::Socket::INET->new now sets $! correctly on failure. $@ is
+still set for backwards compatibility.
+
+=item JPL
+
+Java Perl Lingo is now distributed with Perl. See jpl/README
+for more information.
+
+=item lib
+
+C<use lib> now weeds out any trailing duplicate entries.
+C<no lib> removes all named entries.
+
+=item Math::BigInt
+
+The bitwise operations C<<< << >>>, C<<< >> >>>, C<&>, C<|>,
+and C<~> are now supported on bigints.
+
+=item Math::Complex
+
+The accessor methods Re, Im, arg, abs, rho, and theta can now also
+act as mutators (accessor $z->Re(), mutator $z->Re(3)).
+
+The class method C<display_format> and the corresponding object method
+C<display_format>, in addition to accepting just one argument, now can
+also accept a parameter hash. Recognized keys of a parameter hash are
+C<"style">, which corresponds to the old one parameter case, and two
+new parameters: C<"format">, which is a printf()-style format string
+(defaults usually to C<"%.15g">, you can revert to the default by
+setting the format string to C<undef>) used for both parts of a
+complex number, and C<"polar_pretty_print"> (defaults to true),
+which controls whether an attempt is made to try to recognize small
+multiples and rationals of pi (2pi, pi/2) at the argument (angle) of a
+polar complex number.
+
+The potentially disruptive change is that in list context both methods
+now I<return the parameter hash>, instead of only the value of the
+C<"style"> parameter.
+
+=item Math::Trig
+
+A little bit of radial trigonometry (cylindrical and spherical),
+radial coordinate conversions, and the great circle distance were added.
+
+=item Pod::Parser, Pod::InputObjects
+
+Pod::Parser is a base class for parsing and selecting sections of
+pod documentation from an input stream. This module takes care of
+identifying pod paragraphs and commands in the input and hands off the
+parsed paragraphs and commands to user-defined methods which are free
+to interpret or translate them as they see fit.
+
+Pod::InputObjects defines some input objects needed by Pod::Parser, and
+for advanced users of Pod::Parser that need more about a command besides
+its name and text.
+
+As of release 5.6.0 of Perl, Pod::Parser is now the officially sanctioned
+"base parser code" recommended for use by all pod2xxx translators.
+Pod::Text (pod2text) and Pod::Man (pod2man) have already been converted
+to use Pod::Parser and efforts to convert Pod::HTML (pod2html) are already
+underway. For any questions or comments about pod parsing and translating
+issues and utilities, please use the pod-people@perl.org mailing list.
+
+For further information, please see L<Pod::Parser> and L<Pod::InputObjects>.
+
+=item Pod::Checker, podchecker
+
+This utility checks pod files for correct syntax, according to
+L<perlpod>. Obvious errors are flagged as such, while warnings are
+printed for mistakes that can be handled gracefully. The checklist is
+not complete yet. See L<Pod::Checker>.
+
+=item Pod::ParseUtils, Pod::Find
+
+These modules provide a set of gizmos that are useful mainly for pod
+translators. L<Pod::Find|Pod::Find> traverses directory structures and
+returns found pod files, along with their canonical names (like
+C<File::Spec::Unix>). L<Pod::ParseUtils|Pod::ParseUtils> contains
+B<Pod::List> (useful for storing pod list information), B<Pod::Hyperlink>
+(for parsing the contents of C<LE<lt>E<gt>> sequences) and B<Pod::Cache>
+(for caching information about pod files, e.g., link nodes).
+
+=item Pod::Select, podselect
+
+Pod::Select is a subclass of Pod::Parser which provides a function
+named "podselect()" to filter out user-specified sections of raw pod
+documentation from an input stream. podselect is a script that provides
+access to Pod::Select from other scripts to be used as a filter.
+See L<Pod::Select>.
+
+=item Pod::Usage, pod2usage
+
+Pod::Usage provides the function "pod2usage()" to print usage messages for
+a Perl script based on its embedded pod documentation. The pod2usage()
+function is generally useful to all script authors since it lets them
+write and maintain a single source (the pods) for documentation, thus
+removing the need to create and maintain redundant usage message text
+consisting of information already in the pods.
+
+There is also a pod2usage script which can be used from other kinds of
+scripts to print usage messages from pods (even for non-Perl scripts
+with pods embedded in comments).
+
+For details and examples, please see L<Pod::Usage>.
+
+=item Pod::Text and Pod::Man
+
+Pod::Text has been rewritten to use Pod::Parser. While pod2text() is
+still available for backwards compatibility, the module now has a new
+preferred interface. See L<Pod::Text> for the details. The new Pod::Text
+module is easily subclassed for tweaks to the output, and two such
+subclasses (Pod::Text::Termcap for man-page-style bold and underlining
+using termcap information, and Pod::Text::Color for markup with ANSI color
+sequences) are now standard.
+
+pod2man has been turned into a module, Pod::Man, which also uses
+Pod::Parser. In the process, several outstanding bugs related to quotes
+in section headers, quoting of code escapes, and nested lists have been
+fixed. pod2man is now a wrapper script around this module.
+
+=item SDBM_File
+
+An EXISTS method has been added to this module (and sdbm_exists() has
+been added to the underlying sdbm library), so one can now call exists
+on an SDBM_File tied hash and get the correct result, rather than a
+runtime error.
+
+A bug that may have caused data loss when more than one disk block
+happens to be read from the database in a single FETCH() has been
+fixed.
+
+=item Sys::Syslog
+
+Sys::Syslog now uses XSUBs to access facilities from syslog.h so it
+no longer requires syslog.ph to exist.
+
+=item Sys::Hostname
+
+Sys::Hostname now uses XSUBs to call the C library's gethostname() or
+uname() if they exist.
+
+=item Term::ANSIColor
+
+Term::ANSIColor is a very simple module to provide easy and readable
+access to the ANSI color and highlighting escape sequences, supported by
+most ANSI terminal emulators. It is now included standard.
+
+=item Time::Local
+
+The timelocal() and timegm() functions used to silently return bogus
+results when the date fell outside the machine's integer range. They
+now consistently croak() if the date falls in an unsupported range.
+
+=item Win32
+
+The error return value in list context has been changed for all functions
+that return a list of values. Previously these functions returned a list
+with a single element C<undef> if an error occurred. Now these functions
+return the empty list in these situations. This applies to the following
+functions:
+
+ Win32::FsType
+ Win32::GetOSVersion
+
+The remaining functions are unchanged and continue to return C<undef> on
+error even in list context.
+
+The Win32::SetLastError(ERROR) function has been added as a complement
+to the Win32::GetLastError() function.
+
+The new Win32::GetFullPathName(FILENAME) returns the full absolute
+pathname for FILENAME in scalar context. In list context it returns
+a two-element list containing the fully qualified directory name and
+the filename. See L<Win32>.
+
+=item XSLoader
+
+The XSLoader extension is a simpler alternative to DynaLoader.
+See L<XSLoader>.
+
+=item DBM Filters
+
+A new feature called "DBM Filters" has been added to all the
+DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File.
+DBM Filters add four new methods to each DBM module:
+
+ filter_store_key
+ filter_store_value
+ filter_fetch_key
+ filter_fetch_value
+
+These can be used to filter key-value pairs before the pairs are
+written to the database or just after they are read from the database.
+See L<perldbmfilter> for further information.
+
+=back
+
+=head2 Pragmata
+
+C<use attrs> is now obsolete, and is only provided for
+backward-compatibility. It's been replaced by the C<sub : attributes>
+syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>.
+
+Lexical warnings pragma, C<use warnings;>, to control optional warnings.
+See L<perllexwarn>.
+
+C<use filetest> to control the behaviour of filetests (C<-r> C<-w>
+...). Currently only one subpragma implemented, "use filetest
+'access';", that uses access(2) or equivalent to check permissions
+instead of using stat(2) as usual. This matters in filesystems
+where there are ACLs (access control lists): the stat(2) might lie,
+but access(2) knows better.
+
+The C<open> pragma can be used to specify default disciplines for
+handle constructors (e.g. open()) and for qx//. The two
+pseudo-disciplines C<:raw> and C<:crlf> are currently supported on
+DOS-derivative platforms (i.e. where binmode is not a no-op).
+See also L</"binmode() can be used to set :crlf and :raw modes">.
+
+=head1 Utility Changes
+
+=head2 dprofpp
+
+C<dprofpp> is used to display profile data generated using C<Devel::DProf>.
+See L<dprofpp>.
+
+=head2 find2perl
+
+The C<find2perl> utility now uses the enhanced features of the File::Find
+module. The -depth and -follow options are supported. Pod documentation
+is also included in the script.
+
+=head2 h2xs
+
+The C<h2xs> tool can now work in conjunction with C<C::Scan> (available
+from CPAN) to automatically parse real-life header files. The C<-M>,
+C<-a>, C<-k>, and C<-o> options are new.
+
+=head2 perlcc
+
+C<perlcc> now supports the C and Bytecode backends. By default,
+it generates output from the simple C backend rather than the
+optimized C backend.
+
+Support for non-Unix platforms has been improved.
+
+=head2 perldoc
+
+C<perldoc> has been reworked to avoid possible security holes.
+It will not by default let itself be run as the superuser, but you
+may still use the B<-U> switch to try to make it drop privileges
+first.
+
+=head2 The Perl Debugger
+
+Many bug fixes and enhancements were added to F<perl5db.pl>, the
+Perl debugger. The help documentation was rearranged. New commands
+include C<< < ? >>, C<< > ? >>, and C<< { ? >> to list out current
+actions, C<man I<docpage>> to run your doc viewer on some perl
+docset, and support for quoted options. The help information was
+rearranged, and should be viewable once again if you're using B<less>
+as your pager. A serious security hole was plugged--you should
+immediately remove all older versions of the Perl debugger as
+installed in previous releases, all the way back to perl3, from
+your system to avoid being bitten by this.
+
+=head1 Improved Documentation
+
+Many of the platform-specific README files are now part of the perl
+installation. See L<perl> for the complete list.
+
+=over 4
+
+=item perlapi.pod
+
+The official list of public Perl API functions.
+
+=item perlboot.pod
+
+A tutorial for beginners on object-oriented Perl.
+
+=item perlcompile.pod
+
+An introduction to using the Perl Compiler suite.
+
+=item perldbmfilter.pod
+
+A howto document on using the DBM filter facility.
+
+=item perldebug.pod
+
+All material unrelated to running the Perl debugger, plus all
+low-level guts-like details that risked crushing the casual user
+of the debugger, have been relocated from the old manpage to the
+next entry below.
+
+=item perldebguts.pod
+
+This new manpage contains excessively low-level material not related
+to the Perl debugger, but slightly related to debugging Perl itself.
+It also contains some arcane internal details of how the debugging
+process works that may only be of interest to developers of Perl
+debuggers.
+
+=item perlfork.pod
+
+Notes on the fork() emulation currently available for the Windows platform.
+
+=item perlfilter.pod
+
+An introduction to writing Perl source filters.
+
+=item perlhack.pod
+
+Some guidelines for hacking the Perl source code.
+
+=item perlintern.pod
+
+A list of internal functions in the Perl source code.
+(List is currently empty.)
+
+=item perllexwarn.pod
+
+Introduction and reference information about lexically scoped
+warning categories.
+
+=item perlnumber.pod
+
+Detailed information about numbers as they are represented in Perl.
+
+=item perlopentut.pod
+
+A tutorial on using open() effectively.
+
+=item perlreftut.pod
+
+A tutorial that introduces the essentials of references.
+
+=item perltootc.pod
+
+A tutorial on managing class data for object modules.
+
+=item perltodo.pod
+
+Discussion of the most often wanted features that may someday be
+supported in Perl.
+
+=item perlunicode.pod
+
+An introduction to Unicode support features in Perl.
+
+=back
+
+=head1 Performance enhancements
+
+=head2 Simple sort() using { $a <=> $b } and the like are optimized
+
+Many common sort() operations using a simple inlined block are now
+optimized for faster performance.
+
+=head2 Optimized assignments to lexical variables
+
+Certain operations in the RHS of assignment statements have been
+optimized to directly set the lexical variable on the LHS,
+eliminating redundant copying overheads.
+
+=head2 Faster subroutine calls
+
+Minor changes in how subroutine calls are handled internally
+provide marginal improvements in performance.
+
+=head2 delete(), each(), values() and hash iteration are faster
+
+The hash values returned by delete(), each(), values() and hashes in a
+list context are the actual values in the hash, instead of copies.
+This results in significantly better performance, because it eliminates
+needless copying in most situations.
+
+=head1 Installation and Configuration Improvements
+
+=head2 -Dusethreads means something different
+
+The -Dusethreads flag now enables the experimental interpreter-based thread
+support by default. To get the flavor of experimental threads that was in
+5.005 instead, you need to run Configure with "-Dusethreads -Duse5005threads".
+
+As of v5.6.0, interpreter-threads support is still lacking a way to
+create new threads from Perl (i.e., C<use Thread;> will not work with
+interpreter threads). C<use Thread;> continues to be available when you
+specify the -Duse5005threads option to Configure, bugs and all.
+
+ NOTE: Support for threads continues to be an experimental feature.
+ Interfaces and implementation are subject to sudden and drastic changes.
+
+=head2 New Configure flags
+
+The following new flags may be enabled on the Configure command line
+by running Configure with C<-Dflag>.
+
+ usemultiplicity
+ usethreads useithreads (new interpreter threads: no Perl API yet)
+ usethreads use5005threads (threads as they were in 5.005)
+
+ use64bitint (equal to now deprecated 'use64bits')
+ use64bitall
+
+ uselongdouble
+ usemorebits
+ uselargefiles
+ usesocks (only SOCKS v5 supported)
+
+=head2 Threadedness and 64-bitness now more daring
+
+The Configure options enabling the use of threads and the use of
+64-bitness are now more daring in the sense that they no more have an
+explicit list of operating systems of known threads/64-bit
+capabilities. In other words: if your operating system has the
+necessary APIs and datatypes, you should be able just to go ahead and
+use them, for threads by Configure -Dusethreads, and for 64 bits
+either explicitly by Configure -Duse64bitint or implicitly if your
+system has 64-bit wide datatypes. See also L<"64-bit support">.
+
+=head2 Long Doubles
+
+Some platforms have "long doubles", floating point numbers of even
+larger range than ordinary "doubles". To enable using long doubles for
+Perl's scalars, use -Duselongdouble.
+
+=head2 -Dusemorebits
+
+You can enable both -Duse64bitint and -Duselongdouble with -Dusemorebits.
+See also L<"64-bit support">.
+
+=head2 -Duselargefiles
+
+Some platforms support system APIs that are capable of handling large files
+(typically, files larger than two gigabytes). Perl will try to use these
+APIs if you ask for -Duselargefiles.
+
+See L<"Large file support"> for more information.
+
+=head2 installusrbinperl
+
+You can use "Configure -Uinstallusrbinperl" which causes installperl
+to skip installing perl also as /usr/bin/perl. This is useful if you
+prefer not to modify /usr/bin for some reason or another but harmful
+because many scripts assume to find Perl in /usr/bin/perl.
+
+=head2 SOCKS support
+
+You can use "Configure -Dusesocks" which causes Perl to probe
+for the SOCKS proxy protocol library (v5, not v4). For more information
+on SOCKS, see:
+
+ http://www.socks.nec.com/
+
+=head2 C<-A> flag
+
+You can "post-edit" the Configure variables using the Configure C<-A>
+switch. The editing happens immediately after the platform specific
+hints files have been processed but before the actual configuration
+process starts. Run C<Configure -h> to find out the full C<-A> syntax.
+
+=head2 Enhanced Installation Directories
+
+The installation structure has been enriched to improve the support
+for maintaining multiple versions of perl, to provide locations for
+vendor-supplied modules, scripts, and manpages, and to ease maintenance
+of locally-added modules, scripts, and manpages. See the section on
+Installation Directories in the INSTALL file for complete details.
+For most users building and installing from source, the defaults should
+be fine.
+
+If you previously used C<Configure -Dsitelib> or C<-Dsitearch> to set
+special values for library directories, you might wish to consider using
+the new C<-Dsiteprefix> setting instead. Also, if you wish to re-use a
+config.sh file from an earlier version of perl, you should be sure to
+check that Configure makes sensible choices for the new directories.
+See INSTALL for complete details.
+
+=head2 gcc automatically tried if 'cc' does not seem to be working
+
+In many platforms the vendor-supplied 'cc' is too stripped-down to
+build Perl (basically, the 'cc' doesn't do ANSI C). If this seems
+to be the case and the 'cc' does not seem to be the GNU C compiler
+'gcc', an automatic attempt is made to find and use 'gcc' instead.
+
+=head1 Platform specific changes
+
+=head2 Supported platforms
+
+=over 4
+
+=item *
+
+The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread
+extension.
+
+=item *
+
+GNU/Hurd is now supported.
+
+=item *
+
+Rhapsody/Darwin is now supported.
+
+=item *
+
+EPOC is now supported (on Psion 5).
+
+=item *
+
+The cygwin port (formerly cygwin32) has been greatly improved.
+
+=back
+
+=head2 DOS
+
+=over 4
+
+=item *
+
+Perl now works with djgpp 2.02 (and 2.03 alpha).
+
+=item *
+
+Environment variable names are not converted to uppercase any more.
+
+=item *
+
+Incorrect exit codes from backticks have been fixed.
+
+=item *
+
+This port continues to use its own builtin globbing (not File::Glob).
+
+=back
+
+=head2 OS390 (OpenEdition MVS)
+
+Support for this EBCDIC platform has not been renewed in this release.
+There are difficulties in reconciling Perl's standardization on UTF-8
+as its internal representation for characters with the EBCDIC character
+set, because the two are incompatible.
+
+It is unclear whether future versions will renew support for this
+platform, but the possibility exists.
+
+=head2 VMS
+
+Numerous revisions and extensions to configuration, build, testing, and
+installation process to accommodate core changes and VMS-specific options.
+
+Expand %ENV-handling code to allow runtime mapping to logical names,
+CLI symbols, and CRTL environ array.
+
+Extension of subprocess invocation code to accept filespecs as command
+"verbs".
+
+Add to Perl command line processing the ability to use default file types and
+to recognize Unix-style C<2E<gt>&1>.
+
+Expansion of File::Spec::VMS routines, and integration into ExtUtils::MM_VMS.
+
+Extension of ExtUtils::MM_VMS to handle complex extensions more flexibly.
+
+Barewords at start of Unix-syntax paths may be treated as text rather than
+only as logical names.
+
+Optional secure translation of several logical names used internally by Perl.
+
+Miscellaneous bugfixing and porting of new core code to VMS.
+
+Thanks are gladly extended to the many people who have contributed VMS
+patches, testing, and ideas.
+
+=head2 Win32
+
+Perl can now emulate fork() internally, using multiple interpreters running
+in different concurrent threads. This support must be enabled at build
+time. See L<perlfork> for detailed information.
+
+When given a pathname that consists only of a drivename, such as C<A:>,
+opendir() and stat() now use the current working directory for the drive
+rather than the drive root.
+
+The builtin XSUB functions in the Win32:: namespace are documented. See
+L<Win32>.
+
+$^X now contains the full path name of the running executable.
+
+A Win32::GetLongPathName() function is provided to complement
+Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>.
+
+POSIX::uname() is supported.
+
+system(1,...) now returns true process IDs rather than process
+handles. kill() accepts any real process id, rather than strictly
+return values from system(1,...).
+
+For better compatibility with Unix, C<kill(0, $pid)> can now be used to
+test whether a process exists.
+
+The C<Shell> module is supported.
+
+Better support for building Perl under command.com in Windows 95
+has been added.
+
+Scripts are read in binary mode by default to allow ByteLoader (and
+the filter mechanism in general) to work properly. For compatibility,
+the DATA filehandle will be set to text mode if a carriage return is
+detected at the end of the line containing the __END__ or __DATA__
+token; if not, the DATA filehandle will be left open in binary mode.
+Earlier versions always opened the DATA filehandle in text mode.
+
+The glob() operator is implemented via the C<File::Glob> extension,
+which supports glob syntax of the C shell. This increases the flexibility
+of the glob() operator, but there may be compatibility issues for
+programs that relied on the older globbing syntax. If you want to
+preserve compatibility with the older syntax, you might want to run
+perl with C<-MFile::DosGlob>. For details and compatibility information,
+see L<File::Glob>.
+
+=head1 Significant bug fixes
+
+=head2 <HANDLE> on empty files
+
+With C<$/> set to C<undef>, "slurping" an empty file returns a string of
+zero length (instead of C<undef>, as it used to) the first time the
+HANDLE is read after C<$/> is set to C<undef>. Further reads yield
+C<undef>.
+
+This means that the following will append "foo" to an empty file (it used
+to do nothing):
+
+ perl -0777 -pi -e 's/^/foo/' empty_file
+
+The behaviour of:
+
+ perl -pi -e 's/^/foo/' empty_file
+
+is unchanged (it continues to leave the file empty).
+
+=head2 C<eval '...'> improvements
+
+Line numbers (as reflected by caller() and most diagnostics) within
+C<eval '...'> were often incorrect where here documents were involved.
+This has been corrected.
+
+Lexical lookups for variables appearing in C<eval '...'> within
+functions that were themselves called within an C<eval '...'> were
+searching the wrong place for lexicals. The lexical search now
+correctly ends at the subroutine's block boundary.
+
+The use of C<return> within C<eval {...}> caused $@ not to be reset
+correctly when no exception occurred within the eval. This has
+been fixed.
+
+Parsing of here documents used to be flawed when they appeared as
+the replacement expression in C<eval 's/.../.../e'>. This has
+been fixed.
+
+=head2 All compilation errors are true errors
+
+Some "errors" encountered at compile time were by necessity
+generated as warnings followed by eventual termination of the
+program. This enabled more such errors to be reported in a
+single run, rather than causing a hard stop at the first error
+that was encountered.
+
+The mechanism for reporting such errors has been reimplemented
+to queue compile-time errors and report them at the end of the
+compilation as true errors rather than as warnings. This fixes
+cases where error messages leaked through in the form of warnings
+when code was compiled at run time using C<eval STRING>, and
+also allows such errors to be reliably trapped using C<eval "...">.
+
+=head2 Implicitly closed filehandles are safer
+
+Sometimes implicitly closed filehandles (as when they are localized,
+and Perl automatically closes them on exiting the scope) could
+inadvertently set $? or $!. This has been corrected.
+
+
+=head2 Behavior of list slices is more consistent
+
+When taking a slice of a literal list (as opposed to a slice of
+an array or hash), Perl used to return an empty list if the
+result happened to be composed of all undef values.
+
+The new behavior is to produce an empty list if (and only if)
+the original list was empty. Consider the following example:
+
+ @a = (1,undef,undef,2)[2,1,2];
+
+The old behavior would have resulted in @a having no elements.
+The new behavior ensures it has three undefined elements.
+
+Note in particular that the behavior of slices of the following
+cases remains unchanged:
+
+ @a = ()[1,2];
+ @a = (getpwent)[7,0];
+ @a = (anything_returning_empty_list())[2,1,2];
+ @a = @b[2,1,2];
+ @a = @c{'a','b','c'};
+
+See L<perldata>.
+
+=head2 C<(\$)> prototype and C<$foo{a}>
+
+A scalar reference prototype now correctly allows a hash or
+array element in that slot.
+
+=head2 C<goto &sub> and AUTOLOAD
+
+The C<goto &sub> construct works correctly when C<&sub> happens
+to be autoloaded.
+
+=head2 C<-bareword> allowed under C<use integer>
+
+The autoquoting of barewords preceded by C<-> did not work
+in prior versions when the C<integer> pragma was enabled.
+This has been fixed.
+
+=head2 Failures in DESTROY()
+
+When code in a destructor threw an exception, it went unnoticed
+in earlier versions of Perl, unless someone happened to be
+looking in $@ just after the point the destructor happened to
+run. Such failures are now visible as warnings when warnings are
+enabled.
+
+=head2 Locale bugs fixed
+
+printf() and sprintf() previously reset the numeric locale
+back to the default "C" locale. This has been fixed.
+
+Numbers formatted according to the local numeric locale
+(such as using a decimal comma instead of a decimal dot) caused
+"isn't numeric" warnings, even while the operations accessing
+those numbers produced correct results. These warnings have been
+discontinued.
+
+=head2 Memory leaks
+
+The C<eval 'return sub {...}'> construct could sometimes leak
+memory. This has been fixed.
+
+Operations that aren't filehandle constructors used to leak memory
+when used on invalid filehandles. This has been fixed.
+
+Constructs that modified C<@_> could fail to deallocate values
+in C<@_> and thus leak memory. This has been corrected.
+
+=head2 Spurious subroutine stubs after failed subroutine calls
+
+Perl could sometimes create empty subroutine stubs when a
+subroutine was not found in the package. Such cases stopped
+later method lookups from progressing into base packages.
+This has been corrected.
+
+=head2 Taint failures under C<-U>
+
+When running in unsafe mode, taint violations could sometimes
+cause silent failures. This has been fixed.
+
+=head2 END blocks and the C<-c> switch
+
+Prior versions used to run BEGIN B<and> END blocks when Perl was
+run in compile-only mode. Since this is typically not the expected
+behavior, END blocks are not executed anymore when the C<-c> switch
+is used, or if compilation fails.
+
+See L</"Support for CHECK blocks"> for how to run things when the compile
+phase ends.
+
+=head2 Potential to leak DATA filehandles
+
+Using the C<__DATA__> token creates an implicit filehandle to
+the file that contains the token. It is the program's
+responsibility to close it when it is done reading from it.
+
+This caveat is now better explained in the documentation.
+See L<perldata>.
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item "%s" variable %s masks earlier declaration in same %s
+
+(W misc) A "my" or "our" variable has been redeclared in the current scope or statement,
+effectively eliminating all access to the previous instance. This is almost
+always a typographical error. Note that the earlier variable will still exist
+until the end of the scope or until all closure referents to it are
+destroyed.
+
+=item "my sub" not yet implemented
+
+(F) Lexically scoped subroutines are not yet implemented. Don't try that
+yet.
+
+=item "our" variable %s redeclared
+
+(W misc) You seem to have already declared the same global once before in the
+current lexical scope.
+
+=item '!' allowed only after types %s
+
+(F) The '!' is allowed in pack() and unpack() only after certain types.
+See L<perlfunc/pack>.
+
+=item / cannot take a count
+
+(F) You had an unpack template indicating a counted-length string,
+but you have also specified an explicit size for the string.
+See L<perlfunc/pack>.
+
+=item / must be followed by a, A or Z
+
+(F) You had an unpack template indicating a counted-length string,
+which must be followed by one of the letters a, A or Z
+to indicate what sort of string is to be unpacked.
+See L<perlfunc/pack>.
+
+=item / must be followed by a*, A* or Z*
+
+(F) You had a pack template indicating a counted-length string,
+Currently the only things that can have their length counted are a*, A* or Z*.
+See L<perlfunc/pack>.
+
+=item / must follow a numeric type
+
+(F) You had an unpack template that contained a '#',
+but this did not follow some numeric unpack specification.
+See L<perlfunc/pack>.
+
+=item /%s/: Unrecognized escape \\%c passed through
+
+(W regexp) You used a backslash-character combination which is not recognized
+by Perl. This combination appears in an interpolated variable or a
+C<'>-delimited regular expression. The character was understood literally.
+
+=item /%s/: Unrecognized escape \\%c in character class passed through
+
+(W regexp) You used a backslash-character combination which is not recognized
+by Perl inside character classes. The character was understood literally.
+
+=item /%s/ should probably be written as "%s"
+
+(W syntax) You have used a pattern where Perl expected to find a string,
+as in the first argument to C<join>. Perl will treat the true
+or false result of matching the pattern against $_ as the string,
+which is probably not what you had in mind.
+
+=item %s() called too early to check prototype
+
+(W prototype) You've called a function that has a prototype before the parser saw a
+definition or declaration for it, and Perl could not check that the call
+conforms to the prototype. You need to either add an early prototype
+declaration for the subroutine in question, or move the subroutine
+definition ahead of the call to get proper prototype checking. Alternatively,
+if you are certain that you're calling the function correctly, you may put
+an ampersand before the name to avoid the warning. See L<perlsub>.
+
+=item %s argument is not a HASH or ARRAY element
+
+(F) The argument to exists() must be a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+
+=item %s argument is not a HASH or ARRAY element or slice
+
+(F) The argument to delete() must be either a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+
+or a hash or array slice, such as:
+
+ @foo[$bar, $baz, $xyzzy]
+ @{$ref->[12]}{"susie", "queue"}
+
+=item %s argument is not a subroutine name
+
+(F) The argument to exists() for C<exists &sub> must be a subroutine
+name, and not a subroutine call. C<exists &sub()> will generate this error.
+
+=item %s package attribute may clash with future reserved word: %s
+
+(W reserved) A lowercase attribute name was used that had a package-specific handler.
+That name might have a meaning to Perl itself some day, even though it
+doesn't yet. Perhaps you should use a mixed-case attribute name, instead.
+See L<attributes>.
+
+=item (in cleanup) %s
+
+(W misc) This prefix usually indicates that a DESTROY() method raised
+the indicated exception. Since destructors are usually called by
+the system at arbitrary points during execution, and often a vast
+number of times, the warning is issued only once for any number
+of failures that would otherwise result in the same message being
+repeated.
+
+Failure of user callbacks dispatched using the C<G_KEEPERR> flag
+could also result in this warning. See L<perlcall/G_KEEPERR>.
+
+=item <> should be quotes
+
+(F) You wrote C<< require <file> >> when you should have written
+C<require 'file'>.
+
+=item Attempt to join self
+
+(F) You tried to join a thread from within itself, which is an
+impossible task. You may be joining the wrong thread, or you may
+need to move the join() to some other thread.
+
+=item Bad evalled substitution pattern
+
+(F) You've used the /e switch to evaluate the replacement for a
+substitution, but perl found a syntax error in the code to evaluate,
+most likely an unexpected right brace '}'.
+
+=item Bad realloc() ignored
+
+(S) An internal routine called realloc() on something that had never been
+malloc()ed in the first place. Mandatory, but can be disabled by
+setting environment variable C<PERL_BADFREE> to 1.
+
+=item Bareword found in conditional
+
+(W bareword) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
+It may also indicate a misspelled constant that has been interpreted
+as a bareword:
+
+ use constant TYPO => 1;
+ if (TYOP) { print "foo" }
+
+The C<strict> pragma is useful in avoiding such errors.
+
+=item Binary number > 0b11111111111111111111111111111111 non-portable
+
+(W portable) The binary number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item Bit vector size > 32 non-portable
+
+(W portable) Using bit vector sizes larger than 32 is non-portable.
+
+=item Buffer overflow in prime_env_iter: %s
+
+(W internal) A warning peculiar to VMS. While Perl was preparing to iterate over
+%ENV, it encountered a logical name or symbol definition which was too long,
+so it was truncated to the string shown.
+
+=item Can't check filesystem of script "%s"
+
+(P) For some reason you can't check the filesystem of the script for nosuid.
+
+=item Can't declare class for non-scalar %s in "%s"
+
+(S) Currently, only scalar variables can declared with a specific class
+qualifier in a "my" or "our" declaration. The semantics may be extended
+for other types of variables in future.
+
+=item Can't declare %s in "%s"
+
+(F) Only scalar, array, and hash variables may be declared as "my" or
+"our" variables. They must have ordinary identifiers as names.
+
+=item Can't ignore signal CHLD, forcing to default
+
+(W signal) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled. Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g., cron) is being very careless.
+
+=item Can't modify non-lvalue subroutine call
+
+(F) Subroutines meant to be used in lvalue context should be declared as
+such, see L<perlsub/"Lvalue subroutines">.
+
+=item Can't read CRTL environ
+
+(S) A warning peculiar to VMS. Perl tried to read an element of %ENV
+from the CRTL's internal environment array and discovered the array was
+missing. You need to figure out where your CRTL misplaced its environ
+or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched.
+
+=item Can't remove %s: %s, skipping file
+
+(S) You requested an inplace edit without creating a backup file. Perl
+was unable to remove the original file to replace it with the modified
+file. The file was left unmodified.
+
+=item Can't return %s from lvalue subroutine
+
+(F) Perl detected an attempt to return illegal lvalues (such
+as temporary or readonly values) from a subroutine used as an lvalue.
+This is not allowed.
+
+=item Can't weaken a nonreference
+
+(F) You attempted to weaken something that was not a reference. Only
+references can be weakened.
+
+=item Character class [:%s:] unknown
+
+(F) The class in the character class [: :] syntax is unknown.
+See L<perlre>.
+
+=item Character class syntax [%s] belongs inside character classes
+
+(W unsafe) The character class constructs [: :], [= =], and [. .] go
+I<inside> character classes, the [] are part of the construct,
+for example: /[012[:alpha:]345]/. Note that [= =] and [. .]
+are not currently implemented; they are simply placeholders for
+future extensions.
+
+=item Constant is not %s reference
+
+(F) A constant value (perhaps declared using the C<use constant> pragma)
+is being dereferenced, but it amounts to the wrong type of reference. The
+message indicates the type of reference that was expected. This usually
+indicates a syntax error in dereferencing the constant value.
+See L<perlsub/"Constant Functions"> and L<constant>.
+
+=item constant(%s): %s
+
+(F) The parser found inconsistencies either while attempting to define an
+overloaded constant, or when trying to find the character name specified
+in the C<\N{...}> escape. Perhaps you forgot to load the corresponding
+C<overload> or C<charnames> pragma? See L<charnames> and L<overload>.
+
+=item CORE::%s is not a keyword
+
+(F) The CORE:: namespace is reserved for Perl keywords.
+
+=item defined(@array) is deprecated
+
+(D) defined() is not usually useful on arrays because it checks for an
+undefined I<scalar> value. If you want to see if the array is empty,
+just use C<if (@array) { # not empty }> for example.
+
+=item defined(%hash) is deprecated
+
+(D) defined() is not usually useful on hashes because it checks for an
+undefined I<scalar> value. If you want to see if the hash is empty,
+just use C<if (%hash) { # not empty }> for example.
+
+=item Did not produce a valid header
+
+See Server error.
+
+=item (Did you mean "local" instead of "our"?)
+
+(W misc) Remember that "our" does not localize the declared global variable.
+You have declared it again in the same lexical scope, which seems superfluous.
+
+=item Document contains no data
+
+See Server error.
+
+=item entering effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item false [] range "%s" in regexp
+
+(W regexp) A character class range must start and end at a literal character, not
+another character class like C<\d> or C<[:alpha:]>. The "-" in your false
+range is interpreted as a literal "-". Consider quoting the "-", "\-".
+See L<perlre>.
+
+=item Filehandle %s opened only for output
+
+(W io) You tried to read from a filehandle opened only for writing. If you
+intended it to be a read/write filehandle, you needed to open it with
+"+<" or "+>" or "+>>" instead of with "<" or nothing. If
+you intended only to read from the file, use "<". See
+L<perlfunc/open>.
+
+=item flock() on closed filehandle %s
+
+(W closed) The filehandle you're attempting to flock() got itself closed some
+time before now. Check your logic flow. flock() operates on filehandles.
+Are you attempting to call flock() on a dirhandle by the same name?
+
+=item Global symbol "%s" requires explicit package name
+
+(F) You've said "use strict vars", which indicates that all variables
+must either be lexically scoped (using "my"), declared beforehand using
+"our", or explicitly qualified to say which package the global variable
+is in (using "::").
+
+=item Hexadecimal number > 0xffffffff non-portable
+
+(W portable) The hexadecimal number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item Ill-formed CRTL environ value "%s"
+
+(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's internal
+environ array, and encountered an element without the C<=> delimiter
+used to separate keys from values. The element is ignored.
+
+=item Ill-formed message in prime_env_iter: |%s|
+
+(W internal) A warning peculiar to VMS. Perl tried to read a logical name
+or CLI symbol definition when preparing to iterate over %ENV, and
+didn't see the expected delimiter between key and value, so the
+line was ignored.
+
+=item Illegal binary digit %s
+
+(F) You used a digit other than 0 or 1 in a binary number.
+
+=item Illegal binary digit %s ignored
+
+(W digit) You may have tried to use a digit other than 0 or 1 in a binary number.
+Interpretation of the binary number stopped before the offending digit.
+
+=item Illegal number of bits in vec
+
+(F) The number of bits in vec() (the third argument) must be a power of
+two from 1 to 32 (or 64, if your platform supports that).
+
+=item Integer overflow in %s number
+
+(W overflow) The hexadecimal, octal or binary number you have specified either
+as a literal or as an argument to hex() or oct() is too big for your
+architecture, and has been converted to a floating point number. On a
+32-bit architecture the largest hexadecimal, octal or binary number
+representable without overflow is 0xFFFFFFFF, 037777777777, or
+0b11111111111111111111111111111111 respectively. Note that Perl
+transparently promotes all numbers to a floating point representation
+internally--subject to loss of precision errors in subsequent
+operations.
+
+=item Invalid %s attribute: %s
+
+The indicated attribute for a subroutine or variable was not recognized
+by Perl or by a user-supplied handler. See L<attributes>.
+
+=item Invalid %s attributes: %s
+
+The indicated attributes for a subroutine or variable were not recognized
+by Perl or by a user-supplied handler. See L<attributes>.
+
+=item invalid [] range "%s" in regexp
+
+The offending range is now explicitly displayed.
+
+=item Invalid separator character %s in attribute list
+
+(F) Something other than a colon or whitespace was seen between the
+elements of an attribute list. If the previous attribute
+had a parenthesised parameter list, perhaps that list was terminated
+too soon. See L<attributes>.
+
+=item Invalid separator character %s in subroutine attribute list
+
+(F) Something other than a colon or whitespace was seen between the
+elements of a subroutine attribute list. If the previous attribute
+had a parenthesised parameter list, perhaps that list was terminated
+too soon.
+
+=item leaving effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item Lvalue subs returning %s not implemented yet
+
+(F) Due to limitations in the current implementation, array and hash
+values cannot be returned in subroutines used in lvalue context.
+See L<perlsub/"Lvalue subroutines">.
+
+=item Method %s not permitted
+
+See Server error.
+
+=item Missing %sbrace%s on \N{}
+
+(F) Wrong syntax of character name literal C<\N{charname}> within
+double-quotish context.
+
+=item Missing command in piped open
+
+(W pipe) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
+construction, but the command was missing or blank.
+
+=item Missing name in "my sub"
+
+(F) The reserved syntax for lexically scoped subroutines requires that they
+have a name with which they can be found.
+
+=item No %s specified for -%c
+
+(F) The indicated command line switch needs a mandatory argument, but
+you haven't specified one.
+
+=item No package name allowed for variable %s in "our"
+
+(F) Fully qualified variable names are not allowed in "our" declarations,
+because that doesn't make much sense under existing semantics. Such
+syntax is reserved for future extensions.
+
+=item No space allowed after -%c
+
+(F) The argument to the indicated command line switch must follow immediately
+after the switch, without intervening spaces.
+
+=item no UTC offset information; assuming local time is UTC
+
+(S) A warning peculiar to VMS. Perl was unable to find the local
+timezone offset, so it's assuming that local system time is equivalent
+to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL>
+to translate to the number of seconds which need to be added to UTC to
+get local time.
+
+=item Octal number > 037777777777 non-portable
+
+(W portable) The octal number you specified is larger than 2**32-1 (4294967295)
+and therefore non-portable between systems. See L<perlport> for more
+on portability concerns.
+
+See also L<perlport> for writing portable code.
+
+=item panic: del_backref
+
+(P) Failed an internal consistency check while trying to reset a weak
+reference.
+
+=item panic: kid popen errno read
+
+(F) forked child returned an incomprehensible message about its errno.
+
+=item panic: magic_killbackrefs
+
+(P) Failed an internal consistency check while trying to reset all weak
+references to an object.
+
+=item Parentheses missing around "%s" list
+
+(W parenthesis) You said something like
+
+ my $foo, $bar = @_;
+
+when you meant
+
+ my ($foo, $bar) = @_;
+
+Remember that "my", "our", and "local" bind tighter than comma.
+
+=item Possible unintended interpolation of %s in string
+
+(W ambiguous) It used to be that Perl would try to guess whether you
+wanted an array interpolated or a literal @. It no longer does this;
+arrays are now I<always> interpolated into strings. This means that
+if you try something like:
+
+ print "fred@example.com";
+
+and the array C<@example> doesn't exist, Perl is going to print
+C<fred.com>, which is probably not what you wanted. To get a literal
+C<@> sign in a string, put a backslash before it, just as you would
+to get a literal C<$> sign.
+
+=item Possible Y2K bug: %s
+
+(W y2k) You are concatenating the number 19 with another number, which
+could be a potential Year 2000 problem.
+
+=item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
+
+(W deprecated) You have written something like this:
+
+ sub doit
+ {
+ use attrs qw(locked);
+ }
+
+You should use the new declaration syntax instead.
+
+ sub doit : locked
+ {
+ ...
+
+The C<use attrs> pragma is now obsolete, and is only provided for
+backward-compatibility. See L<perlsub/"Subroutine Attributes">.
+
+
+=item Premature end of script headers
+
+See Server error.
+
+=item Repeat count in pack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/pack>.
+
+=item Repeat count in unpack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/unpack>.
+
+=item realloc() of freed memory ignored
+
+(S) An internal routine called realloc() on something that had already
+been freed.
+
+=item Reference is already weak
+
+(W misc) You have attempted to weaken a reference that is already weak.
+Doing so has no effect.
+
+=item setpgrp can't take arguments
+
+(F) Your system has the setpgrp() from BSD 4.2, which takes no arguments,
+unlike POSIX setpgid(), which takes a process ID and process group ID.
+
+=item Strange *+?{} on zero-length expression
+
+(W regexp) You applied a regular expression quantifier in a place where it
+makes no sense, such as on a zero-width assertion.
+Try putting the quantifier inside the assertion instead. For example,
+the way to match "abc" provided that it is followed by three
+repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+
+=item switching effective %s is not implemented
+
+(F) While under the C<use filetest> pragma, we cannot switch the
+real and effective uids or gids.
+
+=item This Perl can't reset CRTL environ elements (%s)
+
+=item This Perl can't set CRTL environ elements (%s=%s)
+
+(W internal) Warnings peculiar to VMS. You tried to change or delete an element
+of the CRTL's internal environ array, but your copy of Perl wasn't
+built with a CRTL that contained the setenv() function. You'll need to
+rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see
+L<perlvms>) so that the environ array isn't the target of the change to
+%ENV which produced the warning.
+
+=item Too late to run %s block
+
+(W void) A CHECK or INIT block is being defined during run time proper,
+when the opportunity to run them has already passed. Perhaps you are
+loading a file with C<require> or C<do> when you should be using
+C<use> instead. Or perhaps you should put the C<require> or C<do>
+inside a BEGIN block.
+
+=item Unknown open() mode '%s'
+
+(F) The second argument of 3-argument open() is not among the list
+of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
+C<< +> >>, C<<< +>> >>>, C<-|>, C<|->.
+
+=item Unknown process %x sent message to prime_env_iter: %s
+
+(P) An error peculiar to VMS. Perl was reading values for %ENV before
+iterating over it, and someone else stuck a message in the stream of
+data Perl expected. Someone's very confused, or perhaps trying to
+subvert Perl's population of %ENV for nefarious purposes.
+
+=item Unrecognized escape \\%c passed through
+
+(W misc) You used a backslash-character combination which is not recognized
+by Perl. The character was understood literally.
+
+=item Unterminated attribute parameter in attribute list
+
+(F) The lexer saw an opening (left) parenthesis character while parsing an
+attribute list, but the matching closing (right) parenthesis
+character was not found. You may need to add (or remove) a backslash
+character to get your parentheses to balance. See L<attributes>.
+
+=item Unterminated attribute list
+
+(F) The lexer found something other than a simple identifier at the start
+of an attribute, and it wasn't a semicolon or the start of a
+block. Perhaps you terminated the parameter list of the previous attribute
+too soon. See L<attributes>.
+
+=item Unterminated attribute parameter in subroutine attribute list
+
+(F) The lexer saw an opening (left) parenthesis character while parsing a
+subroutine attribute list, but the matching closing (right) parenthesis
+character was not found. You may need to add (or remove) a backslash
+character to get your parentheses to balance.
+
+=item Unterminated subroutine attribute list
+
+(F) The lexer found something other than a simple identifier at the start
+of a subroutine attribute, and it wasn't a semicolon or the start of a
+block. Perhaps you terminated the parameter list of the previous attribute
+too soon.
+
+=item Value of CLI symbol "%s" too long
+
+(W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV
+element from a CLI symbol table, and found a resultant string longer
+than 1024 characters. The return value has been truncated to 1024
+characters.
+
+=item Version number must be a constant number
+
+(P) The attempt to translate a C<use Module n.n LIST> statement into
+its equivalent C<BEGIN> block found an internal inconsistency with
+the version number.
+
+=back
+
+=head1 New tests
+
+=over 4
+
+=item lib/attrs
+
+Compatibility tests for C<sub : attrs> vs the older C<use attrs>.
+
+=item lib/env
+
+Tests for new environment scalar capability (e.g., C<use Env qw($BAR);>).
+
+=item lib/env-array
+
+Tests for new environment array capability (e.g., C<use Env qw(@PATH);>).
+
+=item lib/io_const
+
+IO constants (SEEK_*, _IO*).
+
+=item lib/io_dir
+
+Directory-related IO methods (new, read, close, rewind, tied delete).
+
+=item lib/io_multihomed
+
+INET sockets with multi-homed hosts.
+
+=item lib/io_poll
+
+IO poll().
+
+=item lib/io_unix
+
+UNIX sockets.
+
+=item op/attrs
+
+Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>.
+
+=item op/filetest
+
+File test operators.
+
+=item op/lex_assign
+
+Verify operations that access pad objects (lexicals and temporaries).
+
+=item op/exists_sub
+
+Verify C<exists &sub> operations.
+
+=back
+
+=head1 Incompatible Changes
+
+=head2 Perl Source Incompatibilities
+
+Beware that any new warnings that have been added or old ones
+that have been enhanced are B<not> considered incompatible changes.
+
+Since all new warnings must be explicitly requested via the C<-w>
+switch or the C<warnings> pragma, it is ultimately the programmer's
+responsibility to ensure that warnings are enabled judiciously.
+
+=over 4
+
+=item CHECK is a new keyword
+
+All subroutine definitions named CHECK are now special. See
+C</"Support for CHECK blocks"> for more information.
+
+=item Treatment of list slices of undef has changed
+
+There is a potential incompatibility in the behavior of list slices
+that are comprised entirely of undefined values.
+See L</"Behavior of list slices is more consistent">.
+
+=item Format of $English::PERL_VERSION is different
+
+The English module now sets $PERL_VERSION to $^V (a string value) rather
+than C<$]> (a numeric value). This is a potential incompatibility.
+Send us a report via perlbug if you are affected by this.
+
+See L</"Improved Perl version numbering system"> for the reasons for
+this change.
+
+=item Literals of the form C<1.2.3> parse differently
+
+Previously, numeric literals with more than one dot in them were
+interpreted as a floating point number concatenated with one or more
+numbers. Such "numbers" are now parsed as strings composed of the
+specified ordinals.
+
+For example, C<print 97.98.99> used to output C<97.9899> in earlier
+versions, but now prints C<abc>.
+
+See L</"Support for strings represented as a vector of ordinals">.
+
+=item Possibly changed pseudo-random number generator
+
+Perl programs that depend on reproducing a specific set of pseudo-random
+numbers may now produce different output due to improvements made to the
+rand() builtin. You can use C<sh Configure -Drandfunc=rand> to obtain
+the old behavior.
+
+See L</"Better pseudo-random number generator">.
+
+=item Hashing function for hash keys has changed
+
+Even though Perl hashes are not order preserving, the apparently
+random order encountered when iterating on the contents of a hash
+is actually determined by the hashing algorithm used. Improvements
+in the algorithm may yield a random order that is B<different> from
+that of previous versions, especially when iterating on hashes.
+
+See L</"Better worst-case behavior of hashes"> for additional
+information.
+
+=item C<undef> fails on read only values
+
+Using the C<undef> operator on a readonly value (such as $1) has
+the same effect as assigning C<undef> to the readonly value--it
+throws an exception.
+
+=item Close-on-exec bit may be set on pipe and socket handles
+
+Pipe and socket handles are also now subject to the close-on-exec
+behavior determined by the special variable $^F.
+
+See L</"More consistent close-on-exec behavior">.
+
+=item Writing C<"$$1"> to mean C<"${$}1"> is unsupported
+
+Perl 5.004 deprecated the interpretation of C<$$1> and
+similar within interpolated strings to mean C<$$ . "1">,
+but still allowed it.
+
+In Perl 5.6.0 and later, C<"$$1"> always means C<"${$1}">.
+
+=item delete(), each(), values() and C<\(%h)>
+
+operate on aliases to values, not copies
+
+delete(), each(), values() and hashes (e.g. C<\(%h)>)
+in a list context return the actual
+values in the hash, instead of copies (as they used to in earlier
+versions). Typical idioms for using these constructs copy the
+returned values, but this can make a significant difference when
+creating references to the returned values. Keys in the hash are still
+returned as copies when iterating on a hash.
+
+See also L</"delete(), each(), values() and hash iteration are faster">.
+
+=item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS
+
+vec() generates a run-time error if the BITS argument is not
+a valid power-of-two integer.
+
+=item Text of some diagnostic output has changed
+
+Most references to internal Perl operations in diagnostics
+have been changed to be more descriptive. This may be an
+issue for programs that may incorrectly rely on the exact
+text of diagnostics for proper functioning.
+
+=item C<%@> has been removed
+
+The undocumented special variable C<%@> that used to accumulate
+"background" errors (such as those that happen in DESTROY())
+has been removed, because it could potentially result in memory
+leaks.
+
+=item Parenthesized not() behaves like a list operator
+
+The C<not> operator now falls under the "if it looks like a function,
+it behaves like a function" rule.
+
+As a result, the parenthesized form can be used with C<grep> and C<map>.
+The following construct used to be a syntax error before, but it works
+as expected now:
+
+ grep not($_), @things;
+
+On the other hand, using C<not> with a literal list slice may not
+work. The following previously allowed construct:
+
+ print not (1,2,3)[0];
+
+needs to be written with additional parentheses now:
+
+ print not((1,2,3)[0]);
+
+The behavior remains unaffected when C<not> is not followed by parentheses.
+
+=item Semantics of bareword prototype C<(*)> have changed
+
+The semantics of the bareword prototype C<*> have changed. Perl 5.005
+always coerced simple scalar arguments to a typeglob, which wasn't useful
+in situations where the subroutine must distinguish between a simple
+scalar and a typeglob. The new behavior is to not coerce bareword
+arguments to a typeglob. The value will always be visible as either
+a simple scalar or as a reference to a typeglob.
+
+See L</"More functional bareword prototype (*)">.
+
+=item Semantics of bit operators may have changed on 64-bit platforms
+
+If your platform is either natively 64-bit or if Perl has been
+configured to used 64-bit integers, i.e., $Config{ivsize} is 8,
+there may be a potential incompatibility in the behavior of bitwise
+numeric operators (& | ^ ~ << >>). These operators used to strictly
+operate on the lower 32 bits of integers in previous versions, but now
+operate over the entire native integral width. In particular, note
+that unary C<~> will produce different results on platforms that have
+different $Config{ivsize}. For portability, be sure to mask off
+the excess bits in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
+
+See L</"Bit operators support full native integer width">.
+
+=item More builtins taint their results
+
+As described in L</"Improved security features">, there may be more
+sources of taint in a Perl program.
+
+To avoid these new tainting behaviors, you can build Perl with the
+Configure option C<-Accflags=-DINCOMPLETE_TAINTS>. Beware that the
+ensuing perl binary may be insecure.
+
+=back
+
+=head2 C Source Incompatibilities
+
+=over 4
+
+=item C<PERL_POLLUTE>
+
+Release 5.005 grandfathered old global symbol names by providing preprocessor
+macros for extension source compatibility. As of release 5.6.0, these
+preprocessor definitions are not available by default. You need to explicitly
+compile perl with C<-DPERL_POLLUTE> to get these definitions. For
+extensions still using the old symbols, this option can be
+specified via MakeMaker:
+
+ perl Makefile.PL POLLUTE=1
+
+=item C<PERL_IMPLICIT_CONTEXT>
+
+This new build option provides a set of macros for all API functions
+such that an implicit interpreter/thread context argument is passed to
+every API function. As a result of this, something like C<sv_setsv(foo,bar)>
+amounts to a macro invocation that actually translates to something like
+C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected
+to not have any significant source compatibility issues, the difference
+between a macro and a real function call will need to be considered.
+
+This means that there B<is> a source compatibility issue as a result of
+this if your extensions attempt to use pointers to any of the Perl API
+functions.
+
+Note that the above issue is not relevant to the default build of
+Perl, whose interfaces continue to match those of prior versions
+(but subject to the other options described here).
+
+See L<perlguts/"The Perl API"> for detailed information on the
+ramifications of building Perl with this option.
+
+ NOTE: PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built
+ with one of -Dusethreads, -Dusemultiplicity, or both. It is not
+ intended to be enabled by users at this time.
+
+=item C<PERL_POLLUTE_MALLOC>
+
+Enabling Perl's malloc in release 5.005 and earlier caused the namespace of
+the system's malloc family of functions to be usurped by the Perl versions,
+since by default they used the same names. Besides causing problems on
+platforms that do not allow these functions to be cleanly replaced, this
+also meant that the system versions could not be called in programs that
+used Perl's malloc. Previous versions of Perl have allowed this behaviour
+to be suppressed with the HIDEMYMALLOC and EMBEDMYMALLOC preprocessor
+definitions.
+
+As of release 5.6.0, Perl's malloc family of functions have default names
+distinct from the system versions. You need to explicitly compile perl with
+C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC
+and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now
+the default.
+
+Note that these functions do B<not> constitute Perl's memory allocation API.
+See L<perlguts/"Memory Allocation"> for further information about that.
+
+=back
+
+=head2 Compatible C Source API Changes
+
+=over 4
+
+=item C<PATCHLEVEL> is now C<PERL_VERSION>
+
+The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION>
+are now available by default from perl.h, and reflect the base revision,
+patchlevel, and subversion respectively. C<PERL_REVISION> had no
+prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were
+previously available as C<PATCHLEVEL> and C<SUBVERSION>.
+
+The new names cause less pollution of the B<cpp> namespace and reflect what
+the numbers have come to stand for in common practice. For compatibility,
+the old names are still supported when F<patchlevel.h> is explicitly
+included (as required before), so there is no source incompatibility
+from the change.
+
+=back
+
+=head2 Binary Incompatibilities
+
+In general, the default build of this release is expected to be binary
+compatible for extensions built with the 5.005 release or its maintenance
+versions. However, specific platforms may have broken binary compatibility
+due to changes in the defaults used in hints files. Therefore, please be
+sure to always check the platform-specific README files for any notes to
+the contrary.
+
+The usethreads or usemultiplicity builds are B<not> binary compatible
+with the corresponding builds in 5.005.
+
+On platforms that require an explicit list of exports (AIX, OS/2 and Windows,
+among others), purely internal symbols such as parser functions and the
+run time opcodes are not exported by default. Perl 5.005 used to export
+all functions irrespective of whether they were considered part of the
+public API or not.
+
+For the full list of public API functions, see L<perlapi>.
+
+=head1 Known Problems
+
+=head2 Localizing a tied hash element may leak memory
+
+As of the 5.6.1 release, there is a known leak when code such as this
+is executed:
+
+ use Tie::Hash;
+ tie my %tie_hash => 'Tie::StdHash';
+
+ ...
+
+ local($tie_hash{Foo}) = 1; # leaks
+
+=head2 Known test failures
+
+=over
+
+=item *
+
+64-bit builds
+
+Subtest #15 of lib/b.t may fail under 64-bit builds on platforms such
+as HP-UX PA64 and Linux IA64. The issue is still being investigated.
+
+The lib/io_multihomed test may hang in HP-UX if Perl has been
+configured to be 64-bit. Because other 64-bit platforms do not
+hang in this test, HP-UX is suspect. All other tests pass
+in 64-bit HP-UX. The test attempts to create and connect to
+"multihomed" sockets (sockets which have multiple IP addresses).
+
+Note that 64-bit support is still experimental.
+
+=item *
+
+Failure of Thread tests
+
+The subtests 19 and 20 of lib/thr5005.t test are known to fail due to
+fundamental problems in the 5.005 threading implementation. These are
+not new failures--Perl 5.005_0x has the same bugs, but didn't have these
+tests. (Note that support for 5.005-style threading remains experimental.)
+
+=item *
+
+NEXTSTEP 3.3 POSIX test failure
+
+In NEXTSTEP 3.3p2 the implementation of the strftime(3) in the
+operating system libraries is buggy: the %j format numbers the days of
+a month starting from zero, which, while being logical to programmers,
+will cause the subtests 19 to 27 of the lib/posix test may fail.
+
+=item *
+
+Tru64 (aka Digital UNIX, aka DEC OSF/1) lib/sdbm test failure with gcc
+
+If compiled with gcc 2.95 the lib/sdbm test will fail (dump core).
+The cure is to use the vendor cc, it comes with the operating system
+and produces good code.
+
+=back
+
+=head2 EBCDIC platforms not fully supported
+
+In earlier releases of Perl, EBCDIC environments like OS390 (also
+known as Open Edition MVS) and VM-ESA were supported. Due to changes
+required by the UTF-8 (Unicode) support, the EBCDIC platforms are not
+supported in Perl 5.6.0.
+
+The 5.6.1 release improves support for EBCDIC platforms, but they
+are not fully supported yet.
+
+=head2 UNICOS/mk CC failures during Configure run
+
+In UNICOS/mk the following errors may appear during the Configure run:
+
+ Guessing which symbols your C compiler and preprocessor define...
+ CC-20 cc: ERROR File = try.c, Line = 3
+ ...
+ bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
+ ...
+ 4 errors detected in the compilation of "try.c".
+
+The culprit is the broken awk of UNICOS/mk. The effect is fortunately
+rather mild: Perl itself is not adversely affected by the error, only
+the h2ph utility coming with Perl, and that is rather rarely needed
+these days.
+
+=head2 Arrow operator and arrays
+
+When the left argument to the arrow operator C<< -> >> is an array, or
+the C<scalar> operator operating on an array, the result of the
+operation must be considered erroneous. For example:
+
+ @x->[2]
+ scalar(@x)->[2]
+
+These expressions will get run-time errors in some future release of
+Perl.
+
+=head2 Experimental features
+
+As discussed above, many features are still experimental. Interfaces and
+implementation of these features are subject to change, and in extreme cases,
+even subject to removal in some future release of Perl. These features
+include the following:
+
+=over 4
+
+=item Threads
+
+=item Unicode
+
+=item 64-bit support
+
+=item Lvalue subroutines
+
+=item Weak references
+
+=item The pseudo-hash data type
+
+=item The Compiler suite
+
+=item Internal implementation of file globbing
+
+=item The DB module
+
+=item The regular expression code constructs:
+
+C<(?{ code })> and C<(??{ code })>
+
+=back
+
+=head1 Obsolete Diagnostics
+
+=over 4
+
+=item Character class syntax [: :] is reserved for future extensions
+
+(W) Within regular expression character classes ([]) the syntax beginning
+with "[:" and ending with ":]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[:" and ":\]".
+
+=item Ill-formed logical name |%s| in prime_env_iter
+
+(W) A warning peculiar to VMS. A logical name was encountered when preparing
+to iterate over %ENV which violates the syntactic rules governing logical
+names. Because it cannot be translated normally, it is skipped, and will not
+appear in %ENV. This may be a benign occurrence, as some software packages
+might directly modify logical name tables and introduce nonstandard names,
+or it may indicate that a logical name table has been corrupted.
+
+=item In string, @%s now must be written as \@%s
+
+The description of this error used to say:
+
+ (Someday it will simply assume that an unbackslashed @
+ interpolates an array.)
+
+That day has come, and this fatal error has been removed. It has been
+replaced by a non-fatal warning instead.
+See L</Arrays now always interpolate into double-quoted strings> for
+details.
+
+=item Probable precedence problem on %s
+
+(W) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
+=item regexp too big
+
+(F) The current implementation of regular expressions uses shorts as
+address offsets within a string. Unfortunately this means that if
+the regular expression compiles to longer than 32767, it'll blow up.
+Usually when you want a regular expression this big, there is a better
+way to do it with multiple statements. See L<perlre>.
+
+=item Use of "$$<digit>" to mean "${$}<digit>" is deprecated
+
+(D) Perl versions before 5.004 misinterpreted any type marker followed
+by "$" and a digit. For example, "$$0" was incorrectly taken to mean
+"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
+
+However, the developers of Perl 5.004 could not fix this bug completely,
+because at least two widely-used modules depend on the old meaning of
+"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
+old (broken) way inside strings; but it generates this message as a
+warning. And in Perl 5.005, this special treatment will cease.
+
+=back
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the
+articles recently posted to the comp.lang.perl.misc newsgroup.
+There may also be information at http://www.perl.com/ , the Perl
+Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Gurusamy Sarathy <F<gsar@ActiveState.com>>, with many
+contributions from The Perl Porters.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl56delta.pod b/Master/tlpkg/tlperl/lib/pods/perl56delta.pod
new file mode 100644
index 00000000000..91b4aede499
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl56delta.pod
@@ -0,0 +1,3022 @@
+=head1 NAME
+
+perl56delta - what's new for perl v5.6.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.005 release and the 5.6.0
+release.
+
+=head1 Core Enhancements
+
+=head2 Interpreter cloning, threads, and concurrency
+
+Perl 5.6.0 introduces the beginnings of support for running multiple
+interpreters concurrently in different threads. In conjunction with
+the perl_clone() API call, which can be used to selectively duplicate
+the state of any given interpreter, it is possible to compile a
+piece of code once in an interpreter, clone that interpreter
+one or more times, and run all the resulting interpreters in distinct
+threads.
+
+On the Windows platform, this feature is used to emulate fork() at the
+interpreter level. See L<perlfork> for details about that.
+
+This feature is still in evolution. It is eventually meant to be used
+to selectively clone a subroutine and data reachable from that
+subroutine in a separate interpreter and run the cloned subroutine
+in a separate thread. Since there is no shared data between the
+interpreters, little or no locking will be needed (unless parts of
+the symbol table are explicitly shared). This is obviously intended
+to be an easy-to-use replacement for the existing threads support.
+
+Support for cloning interpreters and interpreter concurrency can be
+enabled using the -Dusethreads Configure option (see win32/Makefile for
+how to enable it on Windows.) The resulting perl executable will be
+functionally identical to one that was built with -Dmultiplicity, but
+the perl_clone() API call will only be available in the former.
+
+-Dusethreads enables the cpp macro USE_ITHREADS by default, which in turn
+enables Perl source code changes that provide a clear separation between
+the op tree and the data it operates with. The former is immutable, and
+can therefore be shared between an interpreter and all of its clones,
+while the latter is considered local to each interpreter, and is therefore
+copied for each clone.
+
+Note that building Perl with the -Dusemultiplicity Configure option
+is adequate if you wish to run multiple B<independent> interpreters
+concurrently in different threads. -Dusethreads only provides the
+additional functionality of the perl_clone() API call and other
+support for running B<cloned> interpreters concurrently.
+
+ NOTE: This is an experimental feature. Implementation details are
+ subject to change.
+
+=head2 Lexically scoped warning categories
+
+You can now control the granularity of warnings emitted by perl at a finer
+level using the C<use warnings> pragma. L<warnings> and L<perllexwarn>
+have copious documentation on this feature.
+
+=head2 Unicode and UTF-8 support
+
+Perl now uses UTF-8 as its internal representation for character
+strings. The C<utf8> and C<bytes> pragmas are used to control this support
+in the current lexical scope. See L<perlunicode>, L<utf8> and L<bytes> for
+more information.
+
+This feature is expected to evolve quickly to support some form of I/O
+disciplines that can be used to specify the kind of input and output data
+(bytes or characters). Until that happens, additional modules from CPAN
+will be needed to complete the toolkit for dealing with Unicode.
+
+ NOTE: This should be considered an experimental feature. Implementation
+ details are subject to change.
+
+=head2 Support for interpolating named characters
+
+The new C<\N> escape interpolates named characters within strings.
+For example, C<"Hi! \N{WHITE SMILING FACE}"> evaluates to a string
+with a unicode smiley face at the end.
+
+=head2 "our" declarations
+
+An "our" declaration introduces a value that can be best understood
+as a lexically scoped symbolic alias to a global variable in the
+package that was current where the variable was declared. This is
+mostly useful as an alternative to the C<vars> pragma, but also provides
+the opportunity to introduce typing and other attributes for such
+variables. See L<perlfunc/our>.
+
+=head2 Support for strings represented as a vector of ordinals
+
+Literals of the form C<v1.2.3.4> are now parsed as a string composed
+of characters with the specified ordinals. This is an alternative, more
+readable way to construct (possibly unicode) strings instead of
+interpolating characters, as in C<"\x{1}\x{2}\x{3}\x{4}">. The leading
+C<v> may be omitted if there are more than two ordinals, so C<1.2.3> is
+parsed the same as C<v1.2.3>.
+
+Strings written in this form are also useful to represent version "numbers".
+It is easy to compare such version "numbers" (which are really just plain
+strings) using any of the usual string comparison operators C<eq>, C<ne>,
+C<lt>, C<gt>, etc., or perform bitwise string operations on them using C<|>,
+C<&>, etc.
+
+In conjunction with the new C<$^V> magic variable (which contains
+the perl version as a string), such literals can be used as a readable way
+to check if you're running a particular version of Perl:
+
+ # this will parse in older versions of Perl also
+ if ($^V and $^V gt v5.6.0) {
+ # new features supported
+ }
+
+C<require> and C<use> also have some special magic to support such
+literals, but this particular usage should be avoided because it leads to
+misleading error messages under versions of Perl which don't support vector
+strings. Using a true version number will ensure correct behavior in all
+versions of Perl:
+
+ require 5.006; # run time check for v5.6
+ use 5.006_001; # compile time check for v5.6.1
+
+Also, C<sprintf> and C<printf> support the Perl-specific format flag C<%v>
+to print ordinals of characters in arbitrary strings:
+
+ printf "v%vd", $^V; # prints current version, such as "v5.5.650"
+ printf "%*vX", ":", $addr; # formats IPv6 address
+ printf "%*vb", " ", $bits; # displays bitstring
+
+See L<perldata/"Scalar value constructors"> for additional information.
+
+=head2 Improved Perl version numbering system
+
+Beginning with Perl version 5.6.0, the version number convention has been
+changed to a "dotted integer" scheme that is more commonly found in open
+source projects.
+
+Maintenance versions of v5.6.0 will be released as v5.6.1, v5.6.2 etc.
+The next development series following v5.6.0 will be numbered v5.7.x,
+beginning with v5.7.0, and the next major production release following
+v5.6.0 will be v5.8.0.
+
+The English module now sets $PERL_VERSION to $^V (a string value) rather
+than C<$]> (a numeric value). (This is a potential incompatibility.
+Send us a report via perlbug if you are affected by this.)
+
+The v1.2.3 syntax is also now legal in Perl.
+See L<Support for strings represented as a vector of ordinals> for more on that.
+
+To cope with the new versioning system's use of at least three significant
+digits for each version component, the method used for incrementing the
+subversion number has also changed slightly. We assume that versions older
+than v5.6.0 have been incrementing the subversion component in multiples of
+10. Versions after v5.6.0 will increment them by 1. Thus, using the new
+notation, 5.005_03 is the "same" as v5.5.30, and the first maintenance
+version following v5.6.0 will be v5.6.1 (which should be read as being
+equivalent to a floating point value of 5.006_001 in the older format,
+stored in C<$]>).
+
+=head2 New syntax for declaring subroutine attributes
+
+Formerly, if you wanted to mark a subroutine as being a method call or
+as requiring an automatic lock() when it is entered, you had to declare
+that with a C<use attrs> pragma in the body of the subroutine.
+That can now be accomplished with declaration syntax, like this:
+
+ sub mymethod : locked method;
+ ...
+ sub mymethod : locked method {
+ ...
+ }
+
+ sub othermethod :locked :method;
+ ...
+ sub othermethod :locked :method {
+ ...
+ }
+
+
+(Note how only the first C<:> is mandatory, and whitespace surrounding
+the C<:> is optional.)
+
+F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes
+with the stubs they provide. See L<attributes>.
+
+=head2 File and directory handles can be autovivified
+
+Similar to how constructs such as C<< $x->[0] >> autovivify a reference,
+handle constructors (open(), opendir(), pipe(), socketpair(), sysopen(),
+socket(), and accept()) now autovivify a file or directory handle
+if the handle passed to them is an uninitialized scalar variable. This
+allows the constructs such as C<open(my $fh, ...)> and C<open(local $fh,...)>
+to be used to create filehandles that will conveniently be closed
+automatically when the scope ends, provided there are no other references
+to them. This largely eliminates the need for typeglobs when opening
+filehandles that must be passed around, as in the following example:
+
+ sub myopen {
+ open my $fh, "@_"
+ or die "Can't open '@_': $!";
+ return $fh;
+ }
+
+ {
+ my $f = myopen("</etc/motd");
+ print <$f>;
+ # $f implicitly closed here
+ }
+
+=head2 open() with more than two arguments
+
+If open() is passed three arguments instead of two, the second argument
+is used as the mode and the third argument is taken to be the file name.
+This is primarily useful for protecting against unintended magic behavior
+of the traditional two-argument form. See L<perlfunc/open>.
+
+=head2 64-bit support
+
+Any platform that has 64-bit integers either
+
+ (1) natively as longs or ints
+ (2) via special compiler flags
+ (3) using long long or int64_t
+
+is able to use "quads" (64-bit integers) as follows:
+
+=over 4
+
+=item *
+
+constants (decimal, hexadecimal, octal, binary) in the code
+
+=item *
+
+arguments to oct() and hex()
+
+=item *
+
+arguments to print(), printf() and sprintf() (flag prefixes ll, L, q)
+
+=item *
+
+printed as such
+
+=item *
+
+pack() and unpack() "q" and "Q" formats
+
+=item *
+
+in basic arithmetics: + - * / % (NOTE: operating close to the limits
+of the integer values may produce surprising results)
+
+=item *
+
+in bit arithmetics: & | ^ ~ << >> (NOTE: these used to be forced
+to be 32 bits wide but now operate on the full native width.)
+
+=item *
+
+vec()
+
+=back
+
+Note that unless you have the case (a) you will have to configure
+and compile Perl using the -Duse64bitint Configure flag.
+
+ NOTE: The Configure flags -Duselonglong and -Duse64bits have been
+ deprecated. Use -Duse64bitint instead.
+
+There are actually two modes of 64-bitness: the first one is achieved
+using Configure -Duse64bitint and the second one using Configure
+-Duse64bitall. The difference is that the first one is minimal and
+the second one maximal. The first works in more places than the second.
+
+The C<use64bitint> does only as much as is required to get 64-bit
+integers into Perl (this may mean, for example, using "long longs")
+while your memory may still be limited to 2 gigabytes (because your
+pointers could still be 32-bit). Note that the name C<64bitint> does
+not imply that your C compiler will be using 64-bit C<int>s (it might,
+but it doesn't have to): the C<use64bitint> means that you will be
+able to have 64 bits wide scalar values.
+
+The C<use64bitall> goes all the way by attempting to switch also
+integers (if it can), longs (and pointers) to being 64-bit. This may
+create an even more binary incompatible Perl than -Duse64bitint: the
+resulting executable may not run at all in a 32-bit box, or you may
+have to reboot/reconfigure/rebuild your operating system to be 64-bit
+aware.
+
+Natively 64-bit systems like Alpha and Cray need neither -Duse64bitint
+nor -Duse64bitall.
+
+Last but not least: note that due to Perl's habit of always using
+floating point numbers, the quads are still not true integers.
+When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned,
+-9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they
+are silently promoted to floating point numbers, after which they will
+start losing precision (in their lower digits).
+
+ NOTE: 64-bit support is still experimental on most platforms.
+ Existing support only covers the LP64 data model. In particular, the
+ LLP64 data model is not yet supported. 64-bit libraries and system
+ APIs on many platforms have not stabilized--your mileage may vary.
+
+=head2 Large file support
+
+If you have filesystems that support "large files" (files larger than
+2 gigabytes), you may now also be able to create and access them from
+Perl.
+
+ NOTE: The default action is to enable large file support, if
+ available on the platform.
+
+If the large file support is on, and you have a Fcntl constant
+O_LARGEFILE, the O_LARGEFILE is automatically added to the flags
+of sysopen().
+
+Beware that unless your filesystem also supports "sparse files" seeking
+to umpteen petabytes may be inadvisable.
+
+Note that in addition to requiring a proper file system to do large
+files you may also need to adjust your per-process (or your
+per-system, or per-process-group, or per-user-group) maximum filesize
+limits before running Perl scripts that try to handle large files,
+especially if you intend to write such files.
+
+Finally, in addition to your process/process group maximum filesize
+limits, you may have quota limits on your filesystems that stop you
+(your user id or your user group id) from using large files.
+
+Adjusting your process/user/group/file system/operating system limits
+is outside the scope of Perl core language. For process limits, you
+may try increasing the limits using your shell's limits/limit/ulimit
+command before running Perl. The BSD::Resource extension (not
+included with the standard Perl distribution) may also be of use, it
+offers the getrlimit/setrlimit interface that can be used to adjust
+process resource usage limits, including the maximum filesize limit.
+
+=head2 Long doubles
+
+In some systems you may be able to use long doubles to enhance the
+range and precision of your double precision floating point numbers
+(that is, Perl's numbers). Use Configure -Duselongdouble to enable
+this support (if it is available).
+
+=head2 "more bits"
+
+You can "Configure -Dusemorebits" to turn on both the 64-bit support
+and the long double support.
+
+=head2 Enhanced support for sort() subroutines
+
+Perl subroutines with a prototype of C<($$)>, and XSUBs in general, can
+now be used as sort subroutines. In either case, the two elements to
+be compared are passed as normal parameters in @_. See L<perlfunc/sort>.
+
+For unprototyped sort subroutines, the historical behavior of passing
+the elements to be compared as the global variables $a and $b remains
+unchanged.
+
+=head2 C<sort $coderef @foo> allowed
+
+sort() did not accept a subroutine reference as the comparison
+function in earlier versions. This is now permitted.
+
+=head2 File globbing implemented internally
+
+Perl now uses the File::Glob implementation of the glob() operator
+automatically. This avoids using an external csh process and the
+problems associated with it.
+
+ NOTE: This is currently an experimental feature. Interfaces and
+ implementation are subject to change.
+
+=head2 Support for CHECK blocks
+
+In addition to C<BEGIN>, C<INIT>, C<END>, C<DESTROY> and C<AUTOLOAD>,
+subroutines named C<CHECK> are now special. These are queued up during
+compilation and behave similar to END blocks, except they are called at
+the end of compilation rather than at the end of execution. They cannot
+be called directly.
+
+=head2 POSIX character class syntax [: :] supported
+
+For example to match alphabetic characters use /[[:alpha:]]/.
+See L<perlre> for details.
+
+=head2 Better pseudo-random number generator
+
+In 5.005_0x and earlier, perl's rand() function used the C library
+rand(3) function. As of 5.005_52, Configure tests for drand48(),
+random(), and rand() (in that order) and picks the first one it finds.
+
+These changes should result in better random numbers from rand().
+
+=head2 Improved C<qw//> operator
+
+The C<qw//> operator is now evaluated at compile time into a true list
+instead of being replaced with a run time call to C<split()>. This
+removes the confusing misbehaviour of C<qw//> in scalar context, which
+had inherited that behaviour from split().
+
+Thus:
+
+ $foo = ($bar) = qw(a b c); print "$foo|$bar\n";
+
+now correctly prints "3|a", instead of "2|a".
+
+=head2 Better worst-case behavior of hashes
+
+Small changes in the hashing algorithm have been implemented in
+order to improve the distribution of lower order bits in the
+hashed value. This is expected to yield better performance on
+keys that are repeated sequences.
+
+=head2 pack() format 'Z' supported
+
+The new format type 'Z' is useful for packing and unpacking null-terminated
+strings. See L<perlfunc/"pack">.
+
+=head2 pack() format modifier '!' supported
+
+The new format type modifier '!' is useful for packing and unpacking
+native shorts, ints, and longs. See L<perlfunc/"pack">.
+
+=head2 pack() and unpack() support counted strings
+
+The template character '/' can be used to specify a counted string
+type to be packed or unpacked. See L<perlfunc/"pack">.
+
+=head2 Comments in pack() templates
+
+The '#' character in a template introduces a comment up to
+end of the line. This facilitates documentation of pack()
+templates.
+
+=head2 Weak references
+
+In previous versions of Perl, you couldn't cache objects so as
+to allow them to be deleted if the last reference from outside
+the cache is deleted. The reference in the cache would hold a
+reference count on the object and the objects would never be
+destroyed.
+
+Another familiar problem is with circular references. When an
+object references itself, its reference count would never go
+down to zero, and it would not get destroyed until the program
+is about to exit.
+
+Weak references solve this by allowing you to "weaken" any
+reference, that is, make it not count towards the reference count.
+When the last non-weak reference to an object is deleted, the object
+is destroyed and all the weak references to the object are
+automatically undef-ed.
+
+To use this feature, you need the Devel::WeakRef package from CPAN, which
+contains additional documentation.
+
+ NOTE: This is an experimental feature. Details are subject to change.
+
+=head2 Binary numbers supported
+
+Binary numbers are now supported as literals, in s?printf formats, and
+C<oct()>:
+
+ $answer = 0b101010;
+ printf "The answer is: %b\n", oct("0b101010");
+
+=head2 Lvalue subroutines
+
+Subroutines can now return modifiable lvalues.
+See L<perlsub/"Lvalue subroutines">.
+
+ NOTE: This is an experimental feature. Details are subject to change.
+
+=head2 Some arrows may be omitted in calls through references
+
+Perl now allows the arrow to be omitted in many constructs
+involving subroutine calls through references. For example,
+C<< $foo[10]->('foo') >> may now be written C<$foo[10]('foo')>.
+This is rather similar to how the arrow may be omitted from
+C<< $foo[10]->{'foo'} >>. Note however, that the arrow is still
+required for C<< foo(10)->('bar') >>.
+
+=head2 Boolean assignment operators are legal lvalues
+
+Constructs such as C<($a ||= 2) += 1> are now allowed.
+
+=head2 exists() is supported on subroutine names
+
+The exists() builtin now works on subroutine names. A subroutine
+is considered to exist if it has been declared (even if implicitly).
+See L<perlfunc/exists> for examples.
+
+=head2 exists() and delete() are supported on array elements
+
+The exists() and delete() builtins now work on simple arrays as well.
+The behavior is similar to that on hash elements.
+
+exists() can be used to check whether an array element has been
+initialized. This avoids autovivifying array elements that don't exist.
+If the array is tied, the EXISTS() method in the corresponding tied
+package will be invoked.
+
+delete() may be used to remove an element from the array and return
+it. The array element at that position returns to its uninitialized
+state, so that testing for the same element with exists() will return
+false. If the element happens to be the one at the end, the size of
+the array also shrinks up to the highest element that tests true for
+exists(), or 0 if none such is found. If the array is tied, the DELETE()
+method in the corresponding tied package will be invoked.
+
+See L<perlfunc/exists> and L<perlfunc/delete> for examples.
+
+=head2 Pseudo-hashes work better
+
+Dereferencing some types of reference values in a pseudo-hash,
+such as C<< $ph->{foo}[1] >>, was accidentally disallowed. This has
+been corrected.
+
+When applied to a pseudo-hash element, exists() now reports whether
+the specified value exists, not merely if the key is valid.
+
+delete() now works on pseudo-hashes. When given a pseudo-hash element
+or slice it deletes the values corresponding to the keys (but not the keys
+themselves). See L<perlref/"Pseudo-hashes: Using an array as a hash">.
+
+Pseudo-hash slices with constant keys are now optimized to array lookups
+at compile-time.
+
+List assignments to pseudo-hash slices are now supported.
+
+The C<fields> pragma now provides ways to create pseudo-hashes, via
+fields::new() and fields::phash(). See L<fields>.
+
+ NOTE: The pseudo-hash data type continues to be experimental.
+ Limiting oneself to the interface elements provided by the
+ fields pragma will provide protection from any future changes.
+
+=head2 Automatic flushing of output buffers
+
+fork(), exec(), system(), qx//, and pipe open()s now flush buffers
+of all files opened for output when the operation was attempted. This
+mostly eliminates confusing buffering mishaps suffered by users unaware
+of how Perl internally handles I/O.
+
+This is not supported on some platforms like Solaris where a suitably
+correct implementation of fflush(NULL) isn't available.
+
+=head2 Better diagnostics on meaningless filehandle operations
+
+Constructs such as C<< open(<FH>) >> and C<< close(<FH>) >>
+are compile time errors. Attempting to read from filehandles that
+were opened only for writing will now produce warnings (just as
+writing to read-only filehandles does).
+
+=head2 Where possible, buffered data discarded from duped input filehandle
+
+C<< open(NEW, "<&OLD") >> now attempts to discard any data that
+was previously read and buffered in C<OLD> before duping the handle.
+On platforms where doing this is allowed, the next read operation
+on C<NEW> will return the same data as the corresponding operation
+on C<OLD>. Formerly, it would have returned the data from the start
+of the following disk block instead.
+
+=head2 eof() has the same old magic as <>
+
+C<eof()> would return true if no attempt to read from C<< <> >> had
+yet been made. C<eof()> has been changed to have a little magic of its
+own, it now opens the C<< <> >> files.
+
+=head2 binmode() can be used to set :crlf and :raw modes
+
+binmode() now accepts a second argument that specifies a discipline
+for the handle in question. The two pseudo-disciplines ":raw" and
+":crlf" are currently supported on DOS-derivative platforms.
+See L<perlfunc/"binmode"> and L<open>.
+
+=head2 C<-T> filetest recognizes UTF-8 encoded files as "text"
+
+The algorithm used for the C<-T> filetest has been enhanced to
+correctly identify UTF-8 content as "text".
+
+=head2 system(), backticks and pipe open now reflect exec() failure
+
+On Unix and similar platforms, system(), qx() and open(FOO, "cmd |")
+etc., are implemented via fork() and exec(). When the underlying
+exec() fails, earlier versions did not report the error properly,
+since the exec() happened to be in a different process.
+
+The child process now communicates with the parent about the
+error in launching the external command, which allows these
+constructs to return with their usual error value and set $!.
+
+=head2 Improved diagnostics
+
+Line numbers are no longer suppressed (under most likely circumstances)
+during the global destruction phase.
+
+Diagnostics emitted from code running in threads other than the main
+thread are now accompanied by the thread ID.
+
+Embedded null characters in diagnostics now actually show up. They
+used to truncate the message in prior versions.
+
+$foo::a and $foo::b are now exempt from "possible typo" warnings only
+if sort() is encountered in package C<foo>.
+
+Unrecognized alphabetic escapes encountered when parsing quote
+constructs now generate a warning, since they may take on new
+semantics in later versions of Perl.
+
+Many diagnostics now report the internal operation in which the warning
+was provoked, like so:
+
+ Use of uninitialized value in concatenation (.) at (eval 1) line 1.
+ Use of uninitialized value in print at (eval 1) line 1.
+
+Diagnostics that occur within eval may also report the file and line
+number where the eval is located, in addition to the eval sequence
+number and the line number within the evaluated text itself. For
+example:
+
+ Not enough arguments for scalar at (eval 4)[newlib/perl5db.pl:1411] line 2, at EOF
+
+=head2 Diagnostics follow STDERR
+
+Diagnostic output now goes to whichever file the C<STDERR> handle
+is pointing at, instead of always going to the underlying C runtime
+library's C<stderr>.
+
+=head2 More consistent close-on-exec behavior
+
+On systems that support a close-on-exec flag on filehandles, the
+flag is now set for any handles created by pipe(), socketpair(),
+socket(), and accept(), if that is warranted by the value of $^F
+that may be in effect. Earlier versions neglected to set the flag
+for handles created with these operators. See L<perlfunc/pipe>,
+L<perlfunc/socketpair>, L<perlfunc/socket>, L<perlfunc/accept>,
+and L<perlvar/$^F>.
+
+=head2 syswrite() ease-of-use
+
+The length argument of C<syswrite()> has become optional.
+
+=head2 Better syntax checks on parenthesized unary operators
+
+Expressions such as:
+
+ print defined(&foo,&bar,&baz);
+ print uc("foo","bar","baz");
+ undef($foo,&bar);
+
+used to be accidentally allowed in earlier versions, and produced
+unpredictable behaviour. Some produced ancillary warnings
+when used in this way; others silently did the wrong thing.
+
+The parenthesized forms of most unary operators that expect a single
+argument now ensure that they are not called with more than one
+argument, making the cases shown above syntax errors. The usual
+behaviour of:
+
+ print defined &foo, &bar, &baz;
+ print uc "foo", "bar", "baz";
+ undef $foo, &bar;
+
+remains unchanged. See L<perlop>.
+
+=head2 Bit operators support full native integer width
+
+The bit operators (& | ^ ~ << >>) now operate on the full native
+integral width (the exact size of which is available in $Config{ivsize}).
+For example, if your platform is either natively 64-bit or if Perl
+has been configured to use 64-bit integers, these operations apply
+to 8 bytes (as opposed to 4 bytes on 32-bit platforms).
+For portability, be sure to mask off the excess bits in the result of
+unary C<~>, e.g., C<~$x & 0xffffffff>.
+
+=head2 Improved security features
+
+More potentially unsafe operations taint their results for improved
+security.
+
+The C<passwd> and C<shell> fields returned by the getpwent(), getpwnam(),
+and getpwuid() are now tainted, because the user can affect their own
+encrypted password and login shell.
+
+The variable modified by shmread(), and messages returned by msgrcv()
+(and its object-oriented interface IPC::SysV::Msg::rcv) are also tainted,
+because other untrusted processes can modify messages and shared memory
+segments for their own nefarious purposes.
+
+=head2 More functional bareword prototype (*)
+
+Bareword prototypes have been rationalized to enable them to be used
+to override builtins that accept barewords and interpret them in
+a special way, such as C<require> or C<do>.
+
+Arguments prototyped as C<*> will now be visible within the subroutine
+as either a simple scalar or as a reference to a typeglob.
+See L<perlsub/Prototypes>.
+
+=head2 C<require> and C<do> may be overridden
+
+C<require> and C<do 'file'> operations may be overridden locally
+by importing subroutines of the same name into the current package
+(or globally by importing them into the CORE::GLOBAL:: namespace).
+Overriding C<require> will also affect C<use>, provided the override
+is visible at compile-time.
+See L<perlsub/"Overriding Built-in Functions">.
+
+=head2 $^X variables may now have names longer than one character
+
+Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax
+error. Now variable names that begin with a control character may be
+arbitrarily long. However, for compatibility reasons, these variables
+I<must> be written with explicit braces, as C<${^XY}> for example.
+C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more
+than one control character, such as C<${^XY^Z}>, are illegal.
+
+The old syntax has not changed. As before, `^X' may be either a
+literal control-X character or the two-character sequence `caret' plus
+`X'. When braces are omitted, the variable name stops after the
+control character. Thus C<"$^XYZ"> continues to be synonymous with
+C<$^X . "YZ"> as before.
+
+As before, lexical variables may not have names beginning with control
+characters. As before, variables whose names begin with a control
+character are always forced to be in package `main'. All such variables
+are reserved for future extensions, except those that begin with
+C<^_>, which may be used by user programs and are guaranteed not to
+acquire special meaning in any future version of Perl.
+
+=head2 New variable $^C reflects C<-c> switch
+
+C<$^C> has a boolean value that reflects whether perl is being run
+in compile-only mode (i.e. via the C<-c> switch). Since
+BEGIN blocks are executed under such conditions, this variable
+enables perl code to determine whether actions that make sense
+only during normal running are warranted. See L<perlvar>.
+
+=head2 New variable $^V contains Perl version as a string
+
+C<$^V> contains the Perl version number as a string composed of
+characters whose ordinals match the version numbers, i.e. v5.6.0.
+This may be used in string comparisons.
+
+See C<Support for strings represented as a vector of ordinals> for an
+example.
+
+=head2 Optional Y2K warnings
+
+If Perl is built with the cpp macro C<PERL_Y2KWARN> defined,
+it emits optional warnings when concatenating the number 19
+with another number.
+
+This behavior must be specifically enabled when running Configure.
+See F<INSTALL> and F<README.Y2K>.
+
+=head2 Arrays now always interpolate into double-quoted strings
+
+In double-quoted strings, arrays now interpolate, no matter what. The
+behavior in earlier versions of perl 5 was that arrays would interpolate
+into strings if the array had been mentioned before the string was
+compiled, and otherwise Perl would raise a fatal compile-time error.
+In versions 5.000 through 5.003, the error was
+
+ Literal @example now requires backslash
+
+In versions 5.004_01 through 5.6.0, the error was
+
+ In string, @example now must be written as \@example
+
+The idea here was to get people into the habit of writing
+C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
+they have always written C<"Give me back my \$5"> when they wanted a
+literal C<$> sign.
+
+Starting with 5.6.1, when Perl now sees an C<@> sign in a
+double-quoted string, it I<always> attempts to interpolate an array,
+regardless of whether or not the array has been used or declared
+already. The fatal error has been downgraded to an optional warning:
+
+ Possible unintended interpolation of @example in string
+
+This warns you that C<"fred@example.com"> is going to turn into
+C<fred.com> if you don't backslash the C<@>.
+See http://perl.plover.com/at-error.html for more details
+about the history here.
+
+=head2 @- and @+ provide starting/ending offsets of regex matches
+
+The new magic variables @- and @+ provide the starting and ending
+offsets, respectively, of $&, $1, $2, etc. See L<perlvar> for
+details.
+
+=head1 Modules and Pragmata
+
+=head2 Modules
+
+=over 4
+
+=item attributes
+
+While used internally by Perl as a pragma, this module also
+provides a way to fetch subroutine and variable attributes.
+See L<attributes>.
+
+=item B
+
+The Perl Compiler suite has been extensively reworked for this
+release. More of the standard Perl test suite passes when run
+under the Compiler, but there is still a significant way to
+go to achieve production quality compiled executables.
+
+ NOTE: The Compiler suite remains highly experimental. The
+ generated code may not be correct, even when it manages to execute
+ without errors.
+
+=item Benchmark
+
+Overall, Benchmark results exhibit lower average error and better timing
+accuracy.
+
+You can now run tests for I<n> seconds instead of guessing the right
+number of tests to run: e.g., timethese(-5, ...) will run each
+code for at least 5 CPU seconds. Zero as the "number of repetitions"
+means "for at least 3 CPU seconds". The output format has also
+changed. For example:
+
+ use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
+
+will now output something like this:
+
+ Benchmark: running a, b, each for at least 5 CPU seconds...
+ a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
+ b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
+
+New features: "each for at least N CPU seconds...", "wallclock secs",
+and the "@ operations/CPU second (n=operations)".
+
+timethese() now returns a reference to a hash of Benchmark objects containing
+the test results, keyed on the names of the tests.
+
+timethis() now returns the iterations field in the Benchmark result object
+instead of 0.
+
+timethese(), timethis(), and the new cmpthese() (see below) can also take
+a format specifier of 'none' to suppress output.
+
+A new function countit() is just like timeit() except that it takes a
+TIME instead of a COUNT.
+
+A new function cmpthese() prints a chart comparing the results of each test
+returned from a timethese() call. For each possible pair of tests, the
+percentage speed difference (iters/sec or seconds/iter) is shown.
+
+For other details, see L<Benchmark>.
+
+=item ByteLoader
+
+The ByteLoader is a dedicated extension to generate and run
+Perl bytecode. See L<ByteLoader>.
+
+=item constant
+
+References can now be used.
+
+The new version also allows a leading underscore in constant names, but
+disallows a double leading underscore (as in "__LINE__"). Some other names
+are disallowed or warned against, including BEGIN, END, etc. Some names
+which were forced into main:: used to fail silently in some cases; now they're
+fatal (outside of main::) and an optional warning (inside of main::).
+The ability to detect whether a constant had been set with a given name has
+been added.
+
+See L<constant>.
+
+=item charnames
+
+This pragma implements the C<\N> string escape. See L<charnames>.
+
+=item Data::Dumper
+
+A C<Maxdepth> setting can be specified to avoid venturing
+too deeply into deep data structures. See L<Data::Dumper>.
+
+The XSUB implementation of Dump() is now automatically called if the
+C<Useqq> setting is not in use.
+
+Dumping C<qr//> objects works correctly.
+
+=item DB
+
+C<DB> is an experimental module that exposes a clean abstraction
+to Perl's debugging API.
+
+=item DB_File
+
+DB_File can now be built with Berkeley DB versions 1, 2 or 3.
+See C<ext/DB_File/Changes>.
+
+=item Devel::DProf
+
+Devel::DProf, a Perl source code profiler has been added. See
+L<Devel::DProf> and L<dprofpp>.
+
+=item Devel::Peek
+
+The Devel::Peek module provides access to the internal representation
+of Perl variables and data. It is a data debugging tool for the XS programmer.
+
+=item Dumpvalue
+
+The Dumpvalue module provides screen dumps of Perl data.
+
+=item DynaLoader
+
+DynaLoader now supports a dl_unload_file() function on platforms that
+support unloading shared objects using dlclose().
+
+Perl can also optionally arrange to unload all extension shared objects
+loaded by Perl. To enable this, build Perl with the Configure option
+C<-Accflags=-DDL_UNLOAD_ALL_AT_EXIT>. (This maybe useful if you are
+using Apache with mod_perl.)
+
+=item English
+
+$PERL_VERSION now stands for C<$^V> (a string value) rather than for C<$]>
+(a numeric value).
+
+=item Env
+
+Env now supports accessing environment variables like PATH as array
+variables.
+
+=item Fcntl
+
+More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
+large file (more than 4GB) access (NOTE: the O_LARGEFILE is
+automatically added to sysopen() flags if large file support has been
+configured, as is the default), Free/Net/OpenBSD locking behaviour
+flags F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the combined
+mask of O_RDONLY, O_WRONLY, and O_RDWR. The seek()/sysseek()
+constants SEEK_SET, SEEK_CUR, and SEEK_END are available via the
+C<:seek> tag. The chmod()/stat() S_IF* constants and S_IS* functions
+are available via the C<:mode> tag.
+
+=item File::Compare
+
+A compare_text() function has been added, which allows custom
+comparison functions. See L<File::Compare>.
+
+=item File::Find
+
+File::Find now works correctly when the wanted() function is either
+autoloaded or is a symbolic reference.
+
+A bug that caused File::Find to lose track of the working directory
+when pruning top-level directories has been fixed.
+
+File::Find now also supports several other options to control its
+behavior. It can follow symbolic links if the C<follow> option is
+specified. Enabling the C<no_chdir> option will make File::Find skip
+changing the current directory when walking directories. The C<untaint>
+flag can be useful when running with taint checks enabled.
+
+See L<File::Find>.
+
+=item File::Glob
+
+This extension implements BSD-style file globbing. By default,
+it will also be used for the internal implementation of the glob()
+operator. See L<File::Glob>.
+
+=item File::Spec
+
+New methods have been added to the File::Spec module: devnull() returns
+the name of the null device (/dev/null on Unix) and tmpdir() the name of
+the temp directory (normally /tmp on Unix). There are now also methods
+to convert between absolute and relative filenames: abs2rel() and
+rel2abs(). For compatibility with operating systems that specify volume
+names in file paths, the splitpath(), splitdir(), and catdir() methods
+have been added.
+
+=item File::Spec::Functions
+
+The new File::Spec::Functions modules provides a function interface
+to the File::Spec module. Allows shorthand
+
+ $fullname = catfile($dir1, $dir2, $file);
+
+instead of
+
+ $fullname = File::Spec->catfile($dir1, $dir2, $file);
+
+=item Getopt::Long
+
+Getopt::Long licensing has changed to allow the Perl Artistic License
+as well as the GPL. It used to be GPL only, which got in the way of
+non-GPL applications that wanted to use Getopt::Long.
+
+Getopt::Long encourages the use of Pod::Usage to produce help
+messages. For example:
+
+ use Getopt::Long;
+ use Pod::Usage;
+ my $man = 0;
+ my $help = 0;
+ GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
+ pod2usage(1) if $help;
+ pod2usage(-exitstatus => 0, -verbose => 2) if $man;
+
+ __END__
+
+ =head1 NAME
+
+ sample - Using Getopt::Long and Pod::Usage
+
+ =head1 SYNOPSIS
+
+ sample [options] [file ...]
+
+ Options:
+ -help brief help message
+ -man full documentation
+
+ =head1 OPTIONS
+
+ =over 8
+
+ =item B<-help>
+
+ Print a brief help message and exits.
+
+ =item B<-man>
+
+ Prints the manual page and exits.
+
+ =back
+
+ =head1 DESCRIPTION
+
+ B<This program> will read the given input file(s) and do something
+ useful with the contents thereof.
+
+ =cut
+
+See L<Pod::Usage> for details.
+
+A bug that prevented the non-option call-back <> from being
+specified as the first argument has been fixed.
+
+To specify the characters < and > as option starters, use ><. Note,
+however, that changing option starters is strongly deprecated.
+
+=item IO
+
+write() and syswrite() will now accept a single-argument
+form of the call, for consistency with Perl's syswrite().
+
+You can now create a TCP-based IO::Socket::INET without forcing
+a connect attempt. This allows you to configure its options
+(like making it non-blocking) and then call connect() manually.
+
+A bug that prevented the IO::Socket::protocol() accessor
+from ever returning the correct value has been corrected.
+
+IO::Socket::connect now uses non-blocking IO instead of alarm()
+to do connect timeouts.
+
+IO::Socket::accept now uses select() instead of alarm() for doing
+timeouts.
+
+IO::Socket::INET->new now sets $! correctly on failure. $@ is
+still set for backwards compatibility.
+
+=item JPL
+
+Java Perl Lingo is now distributed with Perl. See jpl/README
+for more information.
+
+=item lib
+
+C<use lib> now weeds out any trailing duplicate entries.
+C<no lib> removes all named entries.
+
+=item Math::BigInt
+
+The bitwise operations C<<< << >>>, C<<< >> >>>, C<&>, C<|>,
+and C<~> are now supported on bigints.
+
+=item Math::Complex
+
+The accessor methods Re, Im, arg, abs, rho, and theta can now also
+act as mutators (accessor $z->Re(), mutator $z->Re(3)).
+
+The class method C<display_format> and the corresponding object method
+C<display_format>, in addition to accepting just one argument, now can
+also accept a parameter hash. Recognized keys of a parameter hash are
+C<"style">, which corresponds to the old one parameter case, and two
+new parameters: C<"format">, which is a printf()-style format string
+(defaults usually to C<"%.15g">, you can revert to the default by
+setting the format string to C<undef>) used for both parts of a
+complex number, and C<"polar_pretty_print"> (defaults to true),
+which controls whether an attempt is made to try to recognize small
+multiples and rationals of pi (2pi, pi/2) at the argument (angle) of a
+polar complex number.
+
+The potentially disruptive change is that in list context both methods
+now I<return the parameter hash>, instead of only the value of the
+C<"style"> parameter.
+
+=item Math::Trig
+
+A little bit of radial trigonometry (cylindrical and spherical),
+radial coordinate conversions, and the great circle distance were added.
+
+=item Pod::Parser, Pod::InputObjects
+
+Pod::Parser is a base class for parsing and selecting sections of
+pod documentation from an input stream. This module takes care of
+identifying pod paragraphs and commands in the input and hands off the
+parsed paragraphs and commands to user-defined methods which are free
+to interpret or translate them as they see fit.
+
+Pod::InputObjects defines some input objects needed by Pod::Parser, and
+for advanced users of Pod::Parser that need more about a command besides
+its name and text.
+
+As of release 5.6.0 of Perl, Pod::Parser is now the officially sanctioned
+"base parser code" recommended for use by all pod2xxx translators.
+Pod::Text (pod2text) and Pod::Man (pod2man) have already been converted
+to use Pod::Parser and efforts to convert Pod::HTML (pod2html) are already
+underway. For any questions or comments about pod parsing and translating
+issues and utilities, please use the pod-people@perl.org mailing list.
+
+For further information, please see L<Pod::Parser> and L<Pod::InputObjects>.
+
+=item Pod::Checker, podchecker
+
+This utility checks pod files for correct syntax, according to
+L<perlpod>. Obvious errors are flagged as such, while warnings are
+printed for mistakes that can be handled gracefully. The checklist is
+not complete yet. See L<Pod::Checker>.
+
+=item Pod::ParseUtils, Pod::Find
+
+These modules provide a set of gizmos that are useful mainly for pod
+translators. L<Pod::Find|Pod::Find> traverses directory structures and
+returns found pod files, along with their canonical names (like
+C<File::Spec::Unix>). L<Pod::ParseUtils|Pod::ParseUtils> contains
+B<Pod::List> (useful for storing pod list information), B<Pod::Hyperlink>
+(for parsing the contents of C<LE<lt>E<gt>> sequences) and B<Pod::Cache>
+(for caching information about pod files, e.g., link nodes).
+
+=item Pod::Select, podselect
+
+Pod::Select is a subclass of Pod::Parser which provides a function
+named "podselect()" to filter out user-specified sections of raw pod
+documentation from an input stream. podselect is a script that provides
+access to Pod::Select from other scripts to be used as a filter.
+See L<Pod::Select>.
+
+=item Pod::Usage, pod2usage
+
+Pod::Usage provides the function "pod2usage()" to print usage messages for
+a Perl script based on its embedded pod documentation. The pod2usage()
+function is generally useful to all script authors since it lets them
+write and maintain a single source (the pods) for documentation, thus
+removing the need to create and maintain redundant usage message text
+consisting of information already in the pods.
+
+There is also a pod2usage script which can be used from other kinds of
+scripts to print usage messages from pods (even for non-Perl scripts
+with pods embedded in comments).
+
+For details and examples, please see L<Pod::Usage>.
+
+=item Pod::Text and Pod::Man
+
+Pod::Text has been rewritten to use Pod::Parser. While pod2text() is
+still available for backwards compatibility, the module now has a new
+preferred interface. See L<Pod::Text> for the details. The new Pod::Text
+module is easily subclassed for tweaks to the output, and two such
+subclasses (Pod::Text::Termcap for man-page-style bold and underlining
+using termcap information, and Pod::Text::Color for markup with ANSI color
+sequences) are now standard.
+
+pod2man has been turned into a module, Pod::Man, which also uses
+Pod::Parser. In the process, several outstanding bugs related to quotes
+in section headers, quoting of code escapes, and nested lists have been
+fixed. pod2man is now a wrapper script around this module.
+
+=item SDBM_File
+
+An EXISTS method has been added to this module (and sdbm_exists() has
+been added to the underlying sdbm library), so one can now call exists
+on an SDBM_File tied hash and get the correct result, rather than a
+runtime error.
+
+A bug that may have caused data loss when more than one disk block
+happens to be read from the database in a single FETCH() has been
+fixed.
+
+=item Sys::Syslog
+
+Sys::Syslog now uses XSUBs to access facilities from syslog.h so it
+no longer requires syslog.ph to exist.
+
+=item Sys::Hostname
+
+Sys::Hostname now uses XSUBs to call the C library's gethostname() or
+uname() if they exist.
+
+=item Term::ANSIColor
+
+Term::ANSIColor is a very simple module to provide easy and readable
+access to the ANSI color and highlighting escape sequences, supported by
+most ANSI terminal emulators. It is now included standard.
+
+=item Time::Local
+
+The timelocal() and timegm() functions used to silently return bogus
+results when the date fell outside the machine's integer range. They
+now consistently croak() if the date falls in an unsupported range.
+
+=item Win32
+
+The error return value in list context has been changed for all functions
+that return a list of values. Previously these functions returned a list
+with a single element C<undef> if an error occurred. Now these functions
+return the empty list in these situations. This applies to the following
+functions:
+
+ Win32::FsType
+ Win32::GetOSVersion
+
+The remaining functions are unchanged and continue to return C<undef> on
+error even in list context.
+
+The Win32::SetLastError(ERROR) function has been added as a complement
+to the Win32::GetLastError() function.
+
+The new Win32::GetFullPathName(FILENAME) returns the full absolute
+pathname for FILENAME in scalar context. In list context it returns
+a two-element list containing the fully qualified directory name and
+the filename. See L<Win32>.
+
+=item XSLoader
+
+The XSLoader extension is a simpler alternative to DynaLoader.
+See L<XSLoader>.
+
+=item DBM Filters
+
+A new feature called "DBM Filters" has been added to all the
+DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File.
+DBM Filters add four new methods to each DBM module:
+
+ filter_store_key
+ filter_store_value
+ filter_fetch_key
+ filter_fetch_value
+
+These can be used to filter key-value pairs before the pairs are
+written to the database or just after they are read from the database.
+See L<perldbmfilter> for further information.
+
+=back
+
+=head2 Pragmata
+
+C<use attrs> is now obsolete, and is only provided for
+backward-compatibility. It's been replaced by the C<sub : attributes>
+syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>.
+
+Lexical warnings pragma, C<use warnings;>, to control optional warnings.
+See L<perllexwarn>.
+
+C<use filetest> to control the behaviour of filetests (C<-r> C<-w>
+...). Currently only one subpragma implemented, "use filetest
+'access';", that uses access(2) or equivalent to check permissions
+instead of using stat(2) as usual. This matters in filesystems
+where there are ACLs (access control lists): the stat(2) might lie,
+but access(2) knows better.
+
+The C<open> pragma can be used to specify default disciplines for
+handle constructors (e.g. open()) and for qx//. The two
+pseudo-disciplines C<:raw> and C<:crlf> are currently supported on
+DOS-derivative platforms (i.e. where binmode is not a no-op).
+See also L</"binmode() can be used to set :crlf and :raw modes">.
+
+=head1 Utility Changes
+
+=head2 dprofpp
+
+C<dprofpp> is used to display profile data generated using C<Devel::DProf>.
+See L<dprofpp>.
+
+=head2 find2perl
+
+The C<find2perl> utility now uses the enhanced features of the File::Find
+module. The -depth and -follow options are supported. Pod documentation
+is also included in the script.
+
+=head2 h2xs
+
+The C<h2xs> tool can now work in conjunction with C<C::Scan> (available
+from CPAN) to automatically parse real-life header files. The C<-M>,
+C<-a>, C<-k>, and C<-o> options are new.
+
+=head2 perlcc
+
+C<perlcc> now supports the C and Bytecode backends. By default,
+it generates output from the simple C backend rather than the
+optimized C backend.
+
+Support for non-Unix platforms has been improved.
+
+=head2 perldoc
+
+C<perldoc> has been reworked to avoid possible security holes.
+It will not by default let itself be run as the superuser, but you
+may still use the B<-U> switch to try to make it drop privileges
+first.
+
+=head2 The Perl Debugger
+
+Many bug fixes and enhancements were added to F<perl5db.pl>, the
+Perl debugger. The help documentation was rearranged. New commands
+include C<< < ? >>, C<< > ? >>, and C<< { ? >> to list out current
+actions, C<man I<docpage>> to run your doc viewer on some perl
+docset, and support for quoted options. The help information was
+rearranged, and should be viewable once again if you're using B<less>
+as your pager. A serious security hole was plugged--you should
+immediately remove all older versions of the Perl debugger as
+installed in previous releases, all the way back to perl3, from
+your system to avoid being bitten by this.
+
+=head1 Improved Documentation
+
+Many of the platform-specific README files are now part of the perl
+installation. See L<perl> for the complete list.
+
+=over 4
+
+=item perlapi.pod
+
+The official list of public Perl API functions.
+
+=item perlboot.pod
+
+A tutorial for beginners on object-oriented Perl.
+
+=item perlcompile.pod
+
+An introduction to using the Perl Compiler suite.
+
+=item perldbmfilter.pod
+
+A howto document on using the DBM filter facility.
+
+=item perldebug.pod
+
+All material unrelated to running the Perl debugger, plus all
+low-level guts-like details that risked crushing the casual user
+of the debugger, have been relocated from the old manpage to the
+next entry below.
+
+=item perldebguts.pod
+
+This new manpage contains excessively low-level material not related
+to the Perl debugger, but slightly related to debugging Perl itself.
+It also contains some arcane internal details of how the debugging
+process works that may only be of interest to developers of Perl
+debuggers.
+
+=item perlfork.pod
+
+Notes on the fork() emulation currently available for the Windows platform.
+
+=item perlfilter.pod
+
+An introduction to writing Perl source filters.
+
+=item perlhack.pod
+
+Some guidelines for hacking the Perl source code.
+
+=item perlintern.pod
+
+A list of internal functions in the Perl source code.
+(List is currently empty.)
+
+=item perllexwarn.pod
+
+Introduction and reference information about lexically scoped
+warning categories.
+
+=item perlnumber.pod
+
+Detailed information about numbers as they are represented in Perl.
+
+=item perlopentut.pod
+
+A tutorial on using open() effectively.
+
+=item perlreftut.pod
+
+A tutorial that introduces the essentials of references.
+
+=item perltootc.pod
+
+A tutorial on managing class data for object modules.
+
+=item perltodo.pod
+
+Discussion of the most often wanted features that may someday be
+supported in Perl.
+
+=item perlunicode.pod
+
+An introduction to Unicode support features in Perl.
+
+=back
+
+=head1 Performance enhancements
+
+=head2 Simple sort() using { $a <=> $b } and the like are optimized
+
+Many common sort() operations using a simple inlined block are now
+optimized for faster performance.
+
+=head2 Optimized assignments to lexical variables
+
+Certain operations in the RHS of assignment statements have been
+optimized to directly set the lexical variable on the LHS,
+eliminating redundant copying overheads.
+
+=head2 Faster subroutine calls
+
+Minor changes in how subroutine calls are handled internally
+provide marginal improvements in performance.
+
+=head2 delete(), each(), values() and hash iteration are faster
+
+The hash values returned by delete(), each(), values() and hashes in a
+list context are the actual values in the hash, instead of copies.
+This results in significantly better performance, because it eliminates
+needless copying in most situations.
+
+=head1 Installation and Configuration Improvements
+
+=head2 -Dusethreads means something different
+
+The -Dusethreads flag now enables the experimental interpreter-based thread
+support by default. To get the flavor of experimental threads that was in
+5.005 instead, you need to run Configure with "-Dusethreads -Duse5005threads".
+
+As of v5.6.0, interpreter-threads support is still lacking a way to
+create new threads from Perl (i.e., C<use Thread;> will not work with
+interpreter threads). C<use Thread;> continues to be available when you
+specify the -Duse5005threads option to Configure, bugs and all.
+
+ NOTE: Support for threads continues to be an experimental feature.
+ Interfaces and implementation are subject to sudden and drastic changes.
+
+=head2 New Configure flags
+
+The following new flags may be enabled on the Configure command line
+by running Configure with C<-Dflag>.
+
+ usemultiplicity
+ usethreads useithreads (new interpreter threads: no Perl API yet)
+ usethreads use5005threads (threads as they were in 5.005)
+
+ use64bitint (equal to now deprecated 'use64bits')
+ use64bitall
+
+ uselongdouble
+ usemorebits
+ uselargefiles
+ usesocks (only SOCKS v5 supported)
+
+=head2 Threadedness and 64-bitness now more daring
+
+The Configure options enabling the use of threads and the use of
+64-bitness are now more daring in the sense that they no more have an
+explicit list of operating systems of known threads/64-bit
+capabilities. In other words: if your operating system has the
+necessary APIs and datatypes, you should be able just to go ahead and
+use them, for threads by Configure -Dusethreads, and for 64 bits
+either explicitly by Configure -Duse64bitint or implicitly if your
+system has 64-bit wide datatypes. See also L<"64-bit support">.
+
+=head2 Long Doubles
+
+Some platforms have "long doubles", floating point numbers of even
+larger range than ordinary "doubles". To enable using long doubles for
+Perl's scalars, use -Duselongdouble.
+
+=head2 -Dusemorebits
+
+You can enable both -Duse64bitint and -Duselongdouble with -Dusemorebits.
+See also L<"64-bit support">.
+
+=head2 -Duselargefiles
+
+Some platforms support system APIs that are capable of handling large files
+(typically, files larger than two gigabytes). Perl will try to use these
+APIs if you ask for -Duselargefiles.
+
+See L<"Large file support"> for more information.
+
+=head2 installusrbinperl
+
+You can use "Configure -Uinstallusrbinperl" which causes installperl
+to skip installing perl also as /usr/bin/perl. This is useful if you
+prefer not to modify /usr/bin for some reason or another but harmful
+because many scripts assume to find Perl in /usr/bin/perl.
+
+=head2 SOCKS support
+
+You can use "Configure -Dusesocks" which causes Perl to probe
+for the SOCKS proxy protocol library (v5, not v4). For more information
+on SOCKS, see:
+
+ http://www.socks.nec.com/
+
+=head2 C<-A> flag
+
+You can "post-edit" the Configure variables using the Configure C<-A>
+switch. The editing happens immediately after the platform specific
+hints files have been processed but before the actual configuration
+process starts. Run C<Configure -h> to find out the full C<-A> syntax.
+
+=head2 Enhanced Installation Directories
+
+The installation structure has been enriched to improve the support
+for maintaining multiple versions of perl, to provide locations for
+vendor-supplied modules, scripts, and manpages, and to ease maintenance
+of locally-added modules, scripts, and manpages. See the section on
+Installation Directories in the INSTALL file for complete details.
+For most users building and installing from source, the defaults should
+be fine.
+
+If you previously used C<Configure -Dsitelib> or C<-Dsitearch> to set
+special values for library directories, you might wish to consider using
+the new C<-Dsiteprefix> setting instead. Also, if you wish to re-use a
+config.sh file from an earlier version of perl, you should be sure to
+check that Configure makes sensible choices for the new directories.
+See INSTALL for complete details.
+
+=head1 Platform specific changes
+
+=head2 Supported platforms
+
+=over 4
+
+=item *
+
+The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread
+extension.
+
+=item *
+
+GNU/Hurd is now supported.
+
+=item *
+
+Rhapsody/Darwin is now supported.
+
+=item *
+
+EPOC is now supported (on Psion 5).
+
+=item *
+
+The cygwin port (formerly cygwin32) has been greatly improved.
+
+=back
+
+=head2 DOS
+
+=over 4
+
+=item *
+
+Perl now works with djgpp 2.02 (and 2.03 alpha).
+
+=item *
+
+Environment variable names are not converted to uppercase any more.
+
+=item *
+
+Incorrect exit codes from backticks have been fixed.
+
+=item *
+
+This port continues to use its own builtin globbing (not File::Glob).
+
+=back
+
+=head2 OS390 (OpenEdition MVS)
+
+Support for this EBCDIC platform has not been renewed in this release.
+There are difficulties in reconciling Perl's standardization on UTF-8
+as its internal representation for characters with the EBCDIC character
+set, because the two are incompatible.
+
+It is unclear whether future versions will renew support for this
+platform, but the possibility exists.
+
+=head2 VMS
+
+Numerous revisions and extensions to configuration, build, testing, and
+installation process to accommodate core changes and VMS-specific options.
+
+Expand %ENV-handling code to allow runtime mapping to logical names,
+CLI symbols, and CRTL environ array.
+
+Extension of subprocess invocation code to accept filespecs as command
+"verbs".
+
+Add to Perl command line processing the ability to use default file types and
+to recognize Unix-style C<2E<gt>&1>.
+
+Expansion of File::Spec::VMS routines, and integration into ExtUtils::MM_VMS.
+
+Extension of ExtUtils::MM_VMS to handle complex extensions more flexibly.
+
+Barewords at start of Unix-syntax paths may be treated as text rather than
+only as logical names.
+
+Optional secure translation of several logical names used internally by Perl.
+
+Miscellaneous bugfixing and porting of new core code to VMS.
+
+Thanks are gladly extended to the many people who have contributed VMS
+patches, testing, and ideas.
+
+=head2 Win32
+
+Perl can now emulate fork() internally, using multiple interpreters running
+in different concurrent threads. This support must be enabled at build
+time. See L<perlfork> for detailed information.
+
+When given a pathname that consists only of a drivename, such as C<A:>,
+opendir() and stat() now use the current working directory for the drive
+rather than the drive root.
+
+The builtin XSUB functions in the Win32:: namespace are documented. See
+L<Win32>.
+
+$^X now contains the full path name of the running executable.
+
+A Win32::GetLongPathName() function is provided to complement
+Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>.
+
+POSIX::uname() is supported.
+
+system(1,...) now returns true process IDs rather than process
+handles. kill() accepts any real process id, rather than strictly
+return values from system(1,...).
+
+For better compatibility with Unix, C<kill(0, $pid)> can now be used to
+test whether a process exists.
+
+The C<Shell> module is supported.
+
+Better support for building Perl under command.com in Windows 95
+has been added.
+
+Scripts are read in binary mode by default to allow ByteLoader (and
+the filter mechanism in general) to work properly. For compatibility,
+the DATA filehandle will be set to text mode if a carriage return is
+detected at the end of the line containing the __END__ or __DATA__
+token; if not, the DATA filehandle will be left open in binary mode.
+Earlier versions always opened the DATA filehandle in text mode.
+
+The glob() operator is implemented via the C<File::Glob> extension,
+which supports glob syntax of the C shell. This increases the flexibility
+of the glob() operator, but there may be compatibility issues for
+programs that relied on the older globbing syntax. If you want to
+preserve compatibility with the older syntax, you might want to run
+perl with C<-MFile::DosGlob>. For details and compatibility information,
+see L<File::Glob>.
+
+=head1 Significant bug fixes
+
+=head2 <HANDLE> on empty files
+
+With C<$/> set to C<undef>, "slurping" an empty file returns a string of
+zero length (instead of C<undef>, as it used to) the first time the
+HANDLE is read after C<$/> is set to C<undef>. Further reads yield
+C<undef>.
+
+This means that the following will append "foo" to an empty file (it used
+to do nothing):
+
+ perl -0777 -pi -e 's/^/foo/' empty_file
+
+The behaviour of:
+
+ perl -pi -e 's/^/foo/' empty_file
+
+is unchanged (it continues to leave the file empty).
+
+=head2 C<eval '...'> improvements
+
+Line numbers (as reflected by caller() and most diagnostics) within
+C<eval '...'> were often incorrect where here documents were involved.
+This has been corrected.
+
+Lexical lookups for variables appearing in C<eval '...'> within
+functions that were themselves called within an C<eval '...'> were
+searching the wrong place for lexicals. The lexical search now
+correctly ends at the subroutine's block boundary.
+
+The use of C<return> within C<eval {...}> caused $@ not to be reset
+correctly when no exception occurred within the eval. This has
+been fixed.
+
+Parsing of here documents used to be flawed when they appeared as
+the replacement expression in C<eval 's/.../.../e'>. This has
+been fixed.
+
+=head2 All compilation errors are true errors
+
+Some "errors" encountered at compile time were by necessity
+generated as warnings followed by eventual termination of the
+program. This enabled more such errors to be reported in a
+single run, rather than causing a hard stop at the first error
+that was encountered.
+
+The mechanism for reporting such errors has been reimplemented
+to queue compile-time errors and report them at the end of the
+compilation as true errors rather than as warnings. This fixes
+cases where error messages leaked through in the form of warnings
+when code was compiled at run time using C<eval STRING>, and
+also allows such errors to be reliably trapped using C<eval "...">.
+
+=head2 Implicitly closed filehandles are safer
+
+Sometimes implicitly closed filehandles (as when they are localized,
+and Perl automatically closes them on exiting the scope) could
+inadvertently set $? or $!. This has been corrected.
+
+
+=head2 Behavior of list slices is more consistent
+
+When taking a slice of a literal list (as opposed to a slice of
+an array or hash), Perl used to return an empty list if the
+result happened to be composed of all undef values.
+
+The new behavior is to produce an empty list if (and only if)
+the original list was empty. Consider the following example:
+
+ @a = (1,undef,undef,2)[2,1,2];
+
+The old behavior would have resulted in @a having no elements.
+The new behavior ensures it has three undefined elements.
+
+Note in particular that the behavior of slices of the following
+cases remains unchanged:
+
+ @a = ()[1,2];
+ @a = (getpwent)[7,0];
+ @a = (anything_returning_empty_list())[2,1,2];
+ @a = @b[2,1,2];
+ @a = @c{'a','b','c'};
+
+See L<perldata>.
+
+=head2 C<(\$)> prototype and C<$foo{a}>
+
+A scalar reference prototype now correctly allows a hash or
+array element in that slot.
+
+=head2 C<goto &sub> and AUTOLOAD
+
+The C<goto &sub> construct works correctly when C<&sub> happens
+to be autoloaded.
+
+=head2 C<-bareword> allowed under C<use integer>
+
+The autoquoting of barewords preceded by C<-> did not work
+in prior versions when the C<integer> pragma was enabled.
+This has been fixed.
+
+=head2 Failures in DESTROY()
+
+When code in a destructor threw an exception, it went unnoticed
+in earlier versions of Perl, unless someone happened to be
+looking in $@ just after the point the destructor happened to
+run. Such failures are now visible as warnings when warnings are
+enabled.
+
+=head2 Locale bugs fixed
+
+printf() and sprintf() previously reset the numeric locale
+back to the default "C" locale. This has been fixed.
+
+Numbers formatted according to the local numeric locale
+(such as using a decimal comma instead of a decimal dot) caused
+"isn't numeric" warnings, even while the operations accessing
+those numbers produced correct results. These warnings have been
+discontinued.
+
+=head2 Memory leaks
+
+The C<eval 'return sub {...}'> construct could sometimes leak
+memory. This has been fixed.
+
+Operations that aren't filehandle constructors used to leak memory
+when used on invalid filehandles. This has been fixed.
+
+Constructs that modified C<@_> could fail to deallocate values
+in C<@_> and thus leak memory. This has been corrected.
+
+=head2 Spurious subroutine stubs after failed subroutine calls
+
+Perl could sometimes create empty subroutine stubs when a
+subroutine was not found in the package. Such cases stopped
+later method lookups from progressing into base packages.
+This has been corrected.
+
+=head2 Taint failures under C<-U>
+
+When running in unsafe mode, taint violations could sometimes
+cause silent failures. This has been fixed.
+
+=head2 END blocks and the C<-c> switch
+
+Prior versions used to run BEGIN B<and> END blocks when Perl was
+run in compile-only mode. Since this is typically not the expected
+behavior, END blocks are not executed anymore when the C<-c> switch
+is used, or if compilation fails.
+
+See L</"Support for CHECK blocks"> for how to run things when the compile
+phase ends.
+
+=head2 Potential to leak DATA filehandles
+
+Using the C<__DATA__> token creates an implicit filehandle to
+the file that contains the token. It is the program's
+responsibility to close it when it is done reading from it.
+
+This caveat is now better explained in the documentation.
+See L<perldata>.
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item "%s" variable %s masks earlier declaration in same %s
+
+(W misc) A "my" or "our" variable has been redeclared in the current scope or statement,
+effectively eliminating all access to the previous instance. This is almost
+always a typographical error. Note that the earlier variable will still exist
+until the end of the scope or until all closure referents to it are
+destroyed.
+
+=item "my sub" not yet implemented
+
+(F) Lexically scoped subroutines are not yet implemented. Don't try that
+yet.
+
+=item "our" variable %s redeclared
+
+(W misc) You seem to have already declared the same global once before in the
+current lexical scope.
+
+=item '!' allowed only after types %s
+
+(F) The '!' is allowed in pack() and unpack() only after certain types.
+See L<perlfunc/pack>.
+
+=item / cannot take a count
+
+(F) You had an unpack template indicating a counted-length string,
+but you have also specified an explicit size for the string.
+See L<perlfunc/pack>.
+
+=item / must be followed by a, A or Z
+
+(F) You had an unpack template indicating a counted-length string,
+which must be followed by one of the letters a, A or Z
+to indicate what sort of string is to be unpacked.
+See L<perlfunc/pack>.
+
+=item / must be followed by a*, A* or Z*
+
+(F) You had a pack template indicating a counted-length string,
+Currently the only things that can have their length counted are a*, A* or Z*.
+See L<perlfunc/pack>.
+
+=item / must follow a numeric type
+
+(F) You had an unpack template that contained a '#',
+but this did not follow some numeric unpack specification.
+See L<perlfunc/pack>.
+
+=item /%s/: Unrecognized escape \\%c passed through
+
+(W regexp) You used a backslash-character combination which is not recognized
+by Perl. This combination appears in an interpolated variable or a
+C<'>-delimited regular expression. The character was understood literally.
+
+=item /%s/: Unrecognized escape \\%c in character class passed through
+
+(W regexp) You used a backslash-character combination which is not recognized
+by Perl inside character classes. The character was understood literally.
+
+=item /%s/ should probably be written as "%s"
+
+(W syntax) You have used a pattern where Perl expected to find a string,
+as in the first argument to C<join>. Perl will treat the true
+or false result of matching the pattern against $_ as the string,
+which is probably not what you had in mind.
+
+=item %s() called too early to check prototype
+
+(W prototype) You've called a function that has a prototype before the parser saw a
+definition or declaration for it, and Perl could not check that the call
+conforms to the prototype. You need to either add an early prototype
+declaration for the subroutine in question, or move the subroutine
+definition ahead of the call to get proper prototype checking. Alternatively,
+if you are certain that you're calling the function correctly, you may put
+an ampersand before the name to avoid the warning. See L<perlsub>.
+
+=item %s argument is not a HASH or ARRAY element
+
+(F) The argument to exists() must be a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+
+=item %s argument is not a HASH or ARRAY element or slice
+
+(F) The argument to delete() must be either a hash or array element, such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+
+or a hash or array slice, such as:
+
+ @foo[$bar, $baz, $xyzzy]
+ @{$ref->[12]}{"susie", "queue"}
+
+=item %s argument is not a subroutine name
+
+(F) The argument to exists() for C<exists &sub> must be a subroutine
+name, and not a subroutine call. C<exists &sub()> will generate this error.
+
+=item %s package attribute may clash with future reserved word: %s
+
+(W reserved) A lowercase attribute name was used that had a package-specific handler.
+That name might have a meaning to Perl itself some day, even though it
+doesn't yet. Perhaps you should use a mixed-case attribute name, instead.
+See L<attributes>.
+
+=item (in cleanup) %s
+
+(W misc) This prefix usually indicates that a DESTROY() method raised
+the indicated exception. Since destructors are usually called by
+the system at arbitrary points during execution, and often a vast
+number of times, the warning is issued only once for any number
+of failures that would otherwise result in the same message being
+repeated.
+
+Failure of user callbacks dispatched using the C<G_KEEPERR> flag
+could also result in this warning. See L<perlcall/G_KEEPERR>.
+
+=item <> should be quotes
+
+(F) You wrote C<< require <file> >> when you should have written
+C<require 'file'>.
+
+=item Attempt to join self
+
+(F) You tried to join a thread from within itself, which is an
+impossible task. You may be joining the wrong thread, or you may
+need to move the join() to some other thread.
+
+=item Bad evalled substitution pattern
+
+(F) You've used the /e switch to evaluate the replacement for a
+substitution, but perl found a syntax error in the code to evaluate,
+most likely an unexpected right brace '}'.
+
+=item Bad realloc() ignored
+
+(S) An internal routine called realloc() on something that had never been
+malloc()ed in the first place. Mandatory, but can be disabled by
+setting environment variable C<PERL_BADFREE> to 1.
+
+=item Bareword found in conditional
+
+(W bareword) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
+It may also indicate a misspelled constant that has been interpreted
+as a bareword:
+
+ use constant TYPO => 1;
+ if (TYOP) { print "foo" }
+
+The C<strict> pragma is useful in avoiding such errors.
+
+=item Binary number > 0b11111111111111111111111111111111 non-portable
+
+(W portable) The binary number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item Bit vector size > 32 non-portable
+
+(W portable) Using bit vector sizes larger than 32 is non-portable.
+
+=item Buffer overflow in prime_env_iter: %s
+
+(W internal) A warning peculiar to VMS. While Perl was preparing to iterate over
+%ENV, it encountered a logical name or symbol definition which was too long,
+so it was truncated to the string shown.
+
+=item Can't check filesystem of script "%s"
+
+(P) For some reason you can't check the filesystem of the script for nosuid.
+
+=item Can't declare class for non-scalar %s in "%s"
+
+(S) Currently, only scalar variables can declared with a specific class
+qualifier in a "my" or "our" declaration. The semantics may be extended
+for other types of variables in future.
+
+=item Can't declare %s in "%s"
+
+(F) Only scalar, array, and hash variables may be declared as "my" or
+"our" variables. They must have ordinary identifiers as names.
+
+=item Can't ignore signal CHLD, forcing to default
+
+(W signal) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled. Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g., cron) is being very careless.
+
+=item Can't modify non-lvalue subroutine call
+
+(F) Subroutines meant to be used in lvalue context should be declared as
+such, see L<perlsub/"Lvalue subroutines">.
+
+=item Can't read CRTL environ
+
+(S) A warning peculiar to VMS. Perl tried to read an element of %ENV
+from the CRTL's internal environment array and discovered the array was
+missing. You need to figure out where your CRTL misplaced its environ
+or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched.
+
+=item Can't remove %s: %s, skipping file
+
+(S) You requested an inplace edit without creating a backup file. Perl
+was unable to remove the original file to replace it with the modified
+file. The file was left unmodified.
+
+=item Can't return %s from lvalue subroutine
+
+(F) Perl detected an attempt to return illegal lvalues (such
+as temporary or readonly values) from a subroutine used as an lvalue.
+This is not allowed.
+
+=item Can't weaken a nonreference
+
+(F) You attempted to weaken something that was not a reference. Only
+references can be weakened.
+
+=item Character class [:%s:] unknown
+
+(F) The class in the character class [: :] syntax is unknown.
+See L<perlre>.
+
+=item Character class syntax [%s] belongs inside character classes
+
+(W unsafe) The character class constructs [: :], [= =], and [. .] go
+I<inside> character classes, the [] are part of the construct,
+for example: /[012[:alpha:]345]/. Note that [= =] and [. .]
+are not currently implemented; they are simply placeholders for
+future extensions.
+
+=item Constant is not %s reference
+
+(F) A constant value (perhaps declared using the C<use constant> pragma)
+is being dereferenced, but it amounts to the wrong type of reference. The
+message indicates the type of reference that was expected. This usually
+indicates a syntax error in dereferencing the constant value.
+See L<perlsub/"Constant Functions"> and L<constant>.
+
+=item constant(%s): %s
+
+(F) The parser found inconsistencies either while attempting to define an
+overloaded constant, or when trying to find the character name specified
+in the C<\N{...}> escape. Perhaps you forgot to load the corresponding
+C<overload> or C<charnames> pragma? See L<charnames> and L<overload>.
+
+=item CORE::%s is not a keyword
+
+(F) The CORE:: namespace is reserved for Perl keywords.
+
+=item defined(@array) is deprecated
+
+(D) defined() is not usually useful on arrays because it checks for an
+undefined I<scalar> value. If you want to see if the array is empty,
+just use C<if (@array) { # not empty }> for example.
+
+=item defined(%hash) is deprecated
+
+(D) defined() is not usually useful on hashes because it checks for an
+undefined I<scalar> value. If you want to see if the hash is empty,
+just use C<if (%hash) { # not empty }> for example.
+
+=item Did not produce a valid header
+
+See Server error.
+
+=item (Did you mean "local" instead of "our"?)
+
+(W misc) Remember that "our" does not localize the declared global variable.
+You have declared it again in the same lexical scope, which seems superfluous.
+
+=item Document contains no data
+
+See Server error.
+
+=item entering effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item false [] range "%s" in regexp
+
+(W regexp) A character class range must start and end at a literal character, not
+another character class like C<\d> or C<[:alpha:]>. The "-" in your false
+range is interpreted as a literal "-". Consider quoting the "-", "\-".
+See L<perlre>.
+
+=item Filehandle %s opened only for output
+
+(W io) You tried to read from a filehandle opened only for writing. If you
+intended it to be a read/write filehandle, you needed to open it with
+"+<" or "+>" or "+>>" instead of with "<" or nothing. If
+you intended only to read from the file, use "<". See
+L<perlfunc/open>.
+
+=item flock() on closed filehandle %s
+
+(W closed) The filehandle you're attempting to flock() got itself closed some
+time before now. Check your logic flow. flock() operates on filehandles.
+Are you attempting to call flock() on a dirhandle by the same name?
+
+=item Global symbol "%s" requires explicit package name
+
+(F) You've said "use strict vars", which indicates that all variables
+must either be lexically scoped (using "my"), declared beforehand using
+"our", or explicitly qualified to say which package the global variable
+is in (using "::").
+
+=item Hexadecimal number > 0xffffffff non-portable
+
+(W portable) The hexadecimal number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item Ill-formed CRTL environ value "%s"
+
+(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's internal
+environ array, and encountered an element without the C<=> delimiter
+used to separate keys from values. The element is ignored.
+
+=item Ill-formed message in prime_env_iter: |%s|
+
+(W internal) A warning peculiar to VMS. Perl tried to read a logical name
+or CLI symbol definition when preparing to iterate over %ENV, and
+didn't see the expected delimiter between key and value, so the
+line was ignored.
+
+=item Illegal binary digit %s
+
+(F) You used a digit other than 0 or 1 in a binary number.
+
+=item Illegal binary digit %s ignored
+
+(W digit) You may have tried to use a digit other than 0 or 1 in a binary number.
+Interpretation of the binary number stopped before the offending digit.
+
+=item Illegal number of bits in vec
+
+(F) The number of bits in vec() (the third argument) must be a power of
+two from 1 to 32 (or 64, if your platform supports that).
+
+=item Integer overflow in %s number
+
+(W overflow) The hexadecimal, octal or binary number you have specified either
+as a literal or as an argument to hex() or oct() is too big for your
+architecture, and has been converted to a floating point number. On a
+32-bit architecture the largest hexadecimal, octal or binary number
+representable without overflow is 0xFFFFFFFF, 037777777777, or
+0b11111111111111111111111111111111 respectively. Note that Perl
+transparently promotes all numbers to a floating point representation
+internally--subject to loss of precision errors in subsequent
+operations.
+
+=item Invalid %s attribute: %s
+
+The indicated attribute for a subroutine or variable was not recognized
+by Perl or by a user-supplied handler. See L<attributes>.
+
+=item Invalid %s attributes: %s
+
+The indicated attributes for a subroutine or variable were not recognized
+by Perl or by a user-supplied handler. See L<attributes>.
+
+=item invalid [] range "%s" in regexp
+
+The offending range is now explicitly displayed.
+
+=item Invalid separator character %s in attribute list
+
+(F) Something other than a colon or whitespace was seen between the
+elements of an attribute list. If the previous attribute
+had a parenthesised parameter list, perhaps that list was terminated
+too soon. See L<attributes>.
+
+=item Invalid separator character %s in subroutine attribute list
+
+(F) Something other than a colon or whitespace was seen between the
+elements of a subroutine attribute list. If the previous attribute
+had a parenthesised parameter list, perhaps that list was terminated
+too soon.
+
+=item leaving effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item Lvalue subs returning %s not implemented yet
+
+(F) Due to limitations in the current implementation, array and hash
+values cannot be returned in subroutines used in lvalue context.
+See L<perlsub/"Lvalue subroutines">.
+
+=item Method %s not permitted
+
+See Server error.
+
+=item Missing %sbrace%s on \N{}
+
+(F) Wrong syntax of character name literal C<\N{charname}> within
+double-quotish context.
+
+=item Missing command in piped open
+
+(W pipe) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
+construction, but the command was missing or blank.
+
+=item Missing name in "my sub"
+
+(F) The reserved syntax for lexically scoped subroutines requires that they
+have a name with which they can be found.
+
+=item No %s specified for -%c
+
+(F) The indicated command line switch needs a mandatory argument, but
+you haven't specified one.
+
+=item No package name allowed for variable %s in "our"
+
+(F) Fully qualified variable names are not allowed in "our" declarations,
+because that doesn't make much sense under existing semantics. Such
+syntax is reserved for future extensions.
+
+=item No space allowed after -%c
+
+(F) The argument to the indicated command line switch must follow immediately
+after the switch, without intervening spaces.
+
+=item no UTC offset information; assuming local time is UTC
+
+(S) A warning peculiar to VMS. Perl was unable to find the local
+timezone offset, so it's assuming that local system time is equivalent
+to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL>
+to translate to the number of seconds which need to be added to UTC to
+get local time.
+
+=item Octal number > 037777777777 non-portable
+
+(W portable) The octal number you specified is larger than 2**32-1 (4294967295)
+and therefore non-portable between systems. See L<perlport> for more
+on portability concerns.
+
+See also L<perlport> for writing portable code.
+
+=item panic: del_backref
+
+(P) Failed an internal consistency check while trying to reset a weak
+reference.
+
+=item panic: kid popen errno read
+
+(F) forked child returned an incomprehensible message about its errno.
+
+=item panic: magic_killbackrefs
+
+(P) Failed an internal consistency check while trying to reset all weak
+references to an object.
+
+=item Parentheses missing around "%s" list
+
+(W parenthesis) You said something like
+
+ my $foo, $bar = @_;
+
+when you meant
+
+ my ($foo, $bar) = @_;
+
+Remember that "my", "our", and "local" bind tighter than comma.
+
+=item Possible unintended interpolation of %s in string
+
+(W ambiguous) It used to be that Perl would try to guess whether you
+wanted an array interpolated or a literal @. It no longer does this;
+arrays are now I<always> interpolated into strings. This means that
+if you try something like:
+
+ print "fred@example.com";
+
+and the array C<@example> doesn't exist, Perl is going to print
+C<fred.com>, which is probably not what you wanted. To get a literal
+C<@> sign in a string, put a backslash before it, just as you would
+to get a literal C<$> sign.
+
+=item Possible Y2K bug: %s
+
+(W y2k) You are concatenating the number 19 with another number, which
+could be a potential Year 2000 problem.
+
+=item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
+
+(W deprecated) You have written something like this:
+
+ sub doit
+ {
+ use attrs qw(locked);
+ }
+
+You should use the new declaration syntax instead.
+
+ sub doit : locked
+ {
+ ...
+
+The C<use attrs> pragma is now obsolete, and is only provided for
+backward-compatibility. See L<perlsub/"Subroutine Attributes">.
+
+
+=item Premature end of script headers
+
+See Server error.
+
+=item Repeat count in pack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/pack>.
+
+=item Repeat count in unpack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/unpack>.
+
+=item realloc() of freed memory ignored
+
+(S) An internal routine called realloc() on something that had already
+been freed.
+
+=item Reference is already weak
+
+(W misc) You have attempted to weaken a reference that is already weak.
+Doing so has no effect.
+
+=item setpgrp can't take arguments
+
+(F) Your system has the setpgrp() from BSD 4.2, which takes no arguments,
+unlike POSIX setpgid(), which takes a process ID and process group ID.
+
+=item Strange *+?{} on zero-length expression
+
+(W regexp) You applied a regular expression quantifier in a place where it
+makes no sense, such as on a zero-width assertion.
+Try putting the quantifier inside the assertion instead. For example,
+the way to match "abc" provided that it is followed by three
+repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+
+=item switching effective %s is not implemented
+
+(F) While under the C<use filetest> pragma, we cannot switch the
+real and effective uids or gids.
+
+=item This Perl can't reset CRTL environ elements (%s)
+
+=item This Perl can't set CRTL environ elements (%s=%s)
+
+(W internal) Warnings peculiar to VMS. You tried to change or delete an element
+of the CRTL's internal environ array, but your copy of Perl wasn't
+built with a CRTL that contained the setenv() function. You'll need to
+rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see
+L<perlvms>) so that the environ array isn't the target of the change to
+%ENV which produced the warning.
+
+=item Too late to run %s block
+
+(W void) A CHECK or INIT block is being defined during run time proper,
+when the opportunity to run them has already passed. Perhaps you are
+loading a file with C<require> or C<do> when you should be using
+C<use> instead. Or perhaps you should put the C<require> or C<do>
+inside a BEGIN block.
+
+=item Unknown open() mode '%s'
+
+(F) The second argument of 3-argument open() is not among the list
+of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
+C<< +> >>, C<<< +>> >>>, C<-|>, C<|->.
+
+=item Unknown process %x sent message to prime_env_iter: %s
+
+(P) An error peculiar to VMS. Perl was reading values for %ENV before
+iterating over it, and someone else stuck a message in the stream of
+data Perl expected. Someone's very confused, or perhaps trying to
+subvert Perl's population of %ENV for nefarious purposes.
+
+=item Unrecognized escape \\%c passed through
+
+(W misc) You used a backslash-character combination which is not recognized
+by Perl. The character was understood literally.
+
+=item Unterminated attribute parameter in attribute list
+
+(F) The lexer saw an opening (left) parenthesis character while parsing an
+attribute list, but the matching closing (right) parenthesis
+character was not found. You may need to add (or remove) a backslash
+character to get your parentheses to balance. See L<attributes>.
+
+=item Unterminated attribute list
+
+(F) The lexer found something other than a simple identifier at the start
+of an attribute, and it wasn't a semicolon or the start of a
+block. Perhaps you terminated the parameter list of the previous attribute
+too soon. See L<attributes>.
+
+=item Unterminated attribute parameter in subroutine attribute list
+
+(F) The lexer saw an opening (left) parenthesis character while parsing a
+subroutine attribute list, but the matching closing (right) parenthesis
+character was not found. You may need to add (or remove) a backslash
+character to get your parentheses to balance.
+
+=item Unterminated subroutine attribute list
+
+(F) The lexer found something other than a simple identifier at the start
+of a subroutine attribute, and it wasn't a semicolon or the start of a
+block. Perhaps you terminated the parameter list of the previous attribute
+too soon.
+
+=item Value of CLI symbol "%s" too long
+
+(W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV
+element from a CLI symbol table, and found a resultant string longer
+than 1024 characters. The return value has been truncated to 1024
+characters.
+
+=item Version number must be a constant number
+
+(P) The attempt to translate a C<use Module n.n LIST> statement into
+its equivalent C<BEGIN> block found an internal inconsistency with
+the version number.
+
+=back
+
+=head1 New tests
+
+=over 4
+
+=item lib/attrs
+
+Compatibility tests for C<sub : attrs> vs the older C<use attrs>.
+
+=item lib/env
+
+Tests for new environment scalar capability (e.g., C<use Env qw($BAR);>).
+
+=item lib/env-array
+
+Tests for new environment array capability (e.g., C<use Env qw(@PATH);>).
+
+=item lib/io_const
+
+IO constants (SEEK_*, _IO*).
+
+=item lib/io_dir
+
+Directory-related IO methods (new, read, close, rewind, tied delete).
+
+=item lib/io_multihomed
+
+INET sockets with multi-homed hosts.
+
+=item lib/io_poll
+
+IO poll().
+
+=item lib/io_unix
+
+UNIX sockets.
+
+=item op/attrs
+
+Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>.
+
+=item op/filetest
+
+File test operators.
+
+=item op/lex_assign
+
+Verify operations that access pad objects (lexicals and temporaries).
+
+=item op/exists_sub
+
+Verify C<exists &sub> operations.
+
+=back
+
+=head1 Incompatible Changes
+
+=head2 Perl Source Incompatibilities
+
+Beware that any new warnings that have been added or old ones
+that have been enhanced are B<not> considered incompatible changes.
+
+Since all new warnings must be explicitly requested via the C<-w>
+switch or the C<warnings> pragma, it is ultimately the programmer's
+responsibility to ensure that warnings are enabled judiciously.
+
+=over 4
+
+=item CHECK is a new keyword
+
+All subroutine definitions named CHECK are now special. See
+C</"Support for CHECK blocks"> for more information.
+
+=item Treatment of list slices of undef has changed
+
+There is a potential incompatibility in the behavior of list slices
+that are comprised entirely of undefined values.
+See L</"Behavior of list slices is more consistent">.
+
+=item Format of $English::PERL_VERSION is different
+
+The English module now sets $PERL_VERSION to $^V (a string value) rather
+than C<$]> (a numeric value). This is a potential incompatibility.
+Send us a report via perlbug if you are affected by this.
+
+See L</"Improved Perl version numbering system"> for the reasons for
+this change.
+
+=item Literals of the form C<1.2.3> parse differently
+
+Previously, numeric literals with more than one dot in them were
+interpreted as a floating point number concatenated with one or more
+numbers. Such "numbers" are now parsed as strings composed of the
+specified ordinals.
+
+For example, C<print 97.98.99> used to output C<97.9899> in earlier
+versions, but now prints C<abc>.
+
+See L</"Support for strings represented as a vector of ordinals">.
+
+=item Possibly changed pseudo-random number generator
+
+Perl programs that depend on reproducing a specific set of pseudo-random
+numbers may now produce different output due to improvements made to the
+rand() builtin. You can use C<sh Configure -Drandfunc=rand> to obtain
+the old behavior.
+
+See L</"Better pseudo-random number generator">.
+
+=item Hashing function for hash keys has changed
+
+Even though Perl hashes are not order preserving, the apparently
+random order encountered when iterating on the contents of a hash
+is actually determined by the hashing algorithm used. Improvements
+in the algorithm may yield a random order that is B<different> from
+that of previous versions, especially when iterating on hashes.
+
+See L</"Better worst-case behavior of hashes"> for additional
+information.
+
+=item C<undef> fails on read only values
+
+Using the C<undef> operator on a readonly value (such as $1) has
+the same effect as assigning C<undef> to the readonly value--it
+throws an exception.
+
+=item Close-on-exec bit may be set on pipe and socket handles
+
+Pipe and socket handles are also now subject to the close-on-exec
+behavior determined by the special variable $^F.
+
+See L</"More consistent close-on-exec behavior">.
+
+=item Writing C<"$$1"> to mean C<"${$}1"> is unsupported
+
+Perl 5.004 deprecated the interpretation of C<$$1> and
+similar within interpolated strings to mean C<$$ . "1">,
+but still allowed it.
+
+In Perl 5.6.0 and later, C<"$$1"> always means C<"${$1}">.
+
+=item delete(), each(), values() and C<\(%h)>
+
+operate on aliases to values, not copies
+
+delete(), each(), values() and hashes (e.g. C<\(%h)>)
+in a list context return the actual
+values in the hash, instead of copies (as they used to in earlier
+versions). Typical idioms for using these constructs copy the
+returned values, but this can make a significant difference when
+creating references to the returned values. Keys in the hash are still
+returned as copies when iterating on a hash.
+
+See also L</"delete(), each(), values() and hash iteration are faster">.
+
+=item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS
+
+vec() generates a run-time error if the BITS argument is not
+a valid power-of-two integer.
+
+=item Text of some diagnostic output has changed
+
+Most references to internal Perl operations in diagnostics
+have been changed to be more descriptive. This may be an
+issue for programs that may incorrectly rely on the exact
+text of diagnostics for proper functioning.
+
+=item C<%@> has been removed
+
+The undocumented special variable C<%@> that used to accumulate
+"background" errors (such as those that happen in DESTROY())
+has been removed, because it could potentially result in memory
+leaks.
+
+=item Parenthesized not() behaves like a list operator
+
+The C<not> operator now falls under the "if it looks like a function,
+it behaves like a function" rule.
+
+As a result, the parenthesized form can be used with C<grep> and C<map>.
+The following construct used to be a syntax error before, but it works
+as expected now:
+
+ grep not($_), @things;
+
+On the other hand, using C<not> with a literal list slice may not
+work. The following previously allowed construct:
+
+ print not (1,2,3)[0];
+
+needs to be written with additional parentheses now:
+
+ print not((1,2,3)[0]);
+
+The behavior remains unaffected when C<not> is not followed by parentheses.
+
+=item Semantics of bareword prototype C<(*)> have changed
+
+The semantics of the bareword prototype C<*> have changed. Perl 5.005
+always coerced simple scalar arguments to a typeglob, which wasn't useful
+in situations where the subroutine must distinguish between a simple
+scalar and a typeglob. The new behavior is to not coerce bareword
+arguments to a typeglob. The value will always be visible as either
+a simple scalar or as a reference to a typeglob.
+
+See L</"More functional bareword prototype (*)">.
+
+=item Semantics of bit operators may have changed on 64-bit platforms
+
+If your platform is either natively 64-bit or if Perl has been
+configured to used 64-bit integers, i.e., $Config{ivsize} is 8,
+there may be a potential incompatibility in the behavior of bitwise
+numeric operators (& | ^ ~ << >>). These operators used to strictly
+operate on the lower 32 bits of integers in previous versions, but now
+operate over the entire native integral width. In particular, note
+that unary C<~> will produce different results on platforms that have
+different $Config{ivsize}. For portability, be sure to mask off
+the excess bits in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
+
+See L</"Bit operators support full native integer width">.
+
+=item More builtins taint their results
+
+As described in L</"Improved security features">, there may be more
+sources of taint in a Perl program.
+
+To avoid these new tainting behaviors, you can build Perl with the
+Configure option C<-Accflags=-DINCOMPLETE_TAINTS>. Beware that the
+ensuing perl binary may be insecure.
+
+=back
+
+=head2 C Source Incompatibilities
+
+=over 4
+
+=item C<PERL_POLLUTE>
+
+Release 5.005 grandfathered old global symbol names by providing preprocessor
+macros for extension source compatibility. As of release 5.6.0, these
+preprocessor definitions are not available by default. You need to explicitly
+compile perl with C<-DPERL_POLLUTE> to get these definitions. For
+extensions still using the old symbols, this option can be
+specified via MakeMaker:
+
+ perl Makefile.PL POLLUTE=1
+
+=item C<PERL_IMPLICIT_CONTEXT>
+
+This new build option provides a set of macros for all API functions
+such that an implicit interpreter/thread context argument is passed to
+every API function. As a result of this, something like C<sv_setsv(foo,bar)>
+amounts to a macro invocation that actually translates to something like
+C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected
+to not have any significant source compatibility issues, the difference
+between a macro and a real function call will need to be considered.
+
+This means that there B<is> a source compatibility issue as a result of
+this if your extensions attempt to use pointers to any of the Perl API
+functions.
+
+Note that the above issue is not relevant to the default build of
+Perl, whose interfaces continue to match those of prior versions
+(but subject to the other options described here).
+
+See L<perlguts/"The Perl API"> for detailed information on the
+ramifications of building Perl with this option.
+
+ NOTE: PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built
+ with one of -Dusethreads, -Dusemultiplicity, or both. It is not
+ intended to be enabled by users at this time.
+
+=item C<PERL_POLLUTE_MALLOC>
+
+Enabling Perl's malloc in release 5.005 and earlier caused the namespace of
+the system's malloc family of functions to be usurped by the Perl versions,
+since by default they used the same names. Besides causing problems on
+platforms that do not allow these functions to be cleanly replaced, this
+also meant that the system versions could not be called in programs that
+used Perl's malloc. Previous versions of Perl have allowed this behaviour
+to be suppressed with the HIDEMYMALLOC and EMBEDMYMALLOC preprocessor
+definitions.
+
+As of release 5.6.0, Perl's malloc family of functions have default names
+distinct from the system versions. You need to explicitly compile perl with
+C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC
+and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now
+the default.
+
+Note that these functions do B<not> constitute Perl's memory allocation API.
+See L<perlguts/"Memory Allocation"> for further information about that.
+
+=back
+
+=head2 Compatible C Source API Changes
+
+=over 4
+
+=item C<PATCHLEVEL> is now C<PERL_VERSION>
+
+The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION>
+are now available by default from perl.h, and reflect the base revision,
+patchlevel, and subversion respectively. C<PERL_REVISION> had no
+prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were
+previously available as C<PATCHLEVEL> and C<SUBVERSION>.
+
+The new names cause less pollution of the B<cpp> namespace and reflect what
+the numbers have come to stand for in common practice. For compatibility,
+the old names are still supported when F<patchlevel.h> is explicitly
+included (as required before), so there is no source incompatibility
+from the change.
+
+=back
+
+=head2 Binary Incompatibilities
+
+In general, the default build of this release is expected to be binary
+compatible for extensions built with the 5.005 release or its maintenance
+versions. However, specific platforms may have broken binary compatibility
+due to changes in the defaults used in hints files. Therefore, please be
+sure to always check the platform-specific README files for any notes to
+the contrary.
+
+The usethreads or usemultiplicity builds are B<not> binary compatible
+with the corresponding builds in 5.005.
+
+On platforms that require an explicit list of exports (AIX, OS/2 and Windows,
+among others), purely internal symbols such as parser functions and the
+run time opcodes are not exported by default. Perl 5.005 used to export
+all functions irrespective of whether they were considered part of the
+public API or not.
+
+For the full list of public API functions, see L<perlapi>.
+
+=head1 Known Problems
+
+=head2 Thread test failures
+
+The subtests 19 and 20 of lib/thr5005.t test are known to fail due to
+fundamental problems in the 5.005 threading implementation. These are
+not new failures--Perl 5.005_0x has the same bugs, but didn't have these
+tests.
+
+=head2 EBCDIC platforms not supported
+
+In earlier releases of Perl, EBCDIC environments like OS390 (also
+known as Open Edition MVS) and VM-ESA were supported. Due to changes
+required by the UTF-8 (Unicode) support, the EBCDIC platforms are not
+supported in Perl 5.6.0.
+
+=head2 In 64-bit HP-UX the lib/io_multihomed test may hang
+
+The lib/io_multihomed test may hang in HP-UX if Perl has been
+configured to be 64-bit. Because other 64-bit platforms do not
+hang in this test, HP-UX is suspect. All other tests pass
+in 64-bit HP-UX. The test attempts to create and connect to
+"multihomed" sockets (sockets which have multiple IP addresses).
+
+=head2 NEXTSTEP 3.3 POSIX test failure
+
+In NEXTSTEP 3.3p2 the implementation of the strftime(3) in the
+operating system libraries is buggy: the %j format numbers the days of
+a month starting from zero, which, while being logical to programmers,
+will cause the subtests 19 to 27 of the lib/posix test may fail.
+
+=head2 Tru64 (aka Digital UNIX, aka DEC OSF/1) lib/sdbm test failure with gcc
+
+If compiled with gcc 2.95 the lib/sdbm test will fail (dump core).
+The cure is to use the vendor cc, it comes with the operating system
+and produces good code.
+
+=head2 UNICOS/mk CC failures during Configure run
+
+In UNICOS/mk the following errors may appear during the Configure run:
+
+ Guessing which symbols your C compiler and preprocessor define...
+ CC-20 cc: ERROR File = try.c, Line = 3
+ ...
+ bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
+ ...
+ 4 errors detected in the compilation of "try.c".
+
+The culprit is the broken awk of UNICOS/mk. The effect is fortunately
+rather mild: Perl itself is not adversely affected by the error, only
+the h2ph utility coming with Perl, and that is rather rarely needed
+these days.
+
+=head2 Arrow operator and arrays
+
+When the left argument to the arrow operator C<< -> >> is an array, or
+the C<scalar> operator operating on an array, the result of the
+operation must be considered erroneous. For example:
+
+ @x->[2]
+ scalar(@x)->[2]
+
+These expressions will get run-time errors in some future release of
+Perl.
+
+=head2 Experimental features
+
+As discussed above, many features are still experimental. Interfaces and
+implementation of these features are subject to change, and in extreme cases,
+even subject to removal in some future release of Perl. These features
+include the following:
+
+=over 4
+
+=item Threads
+
+=item Unicode
+
+=item 64-bit support
+
+=item Lvalue subroutines
+
+=item Weak references
+
+=item The pseudo-hash data type
+
+=item The Compiler suite
+
+=item Internal implementation of file globbing
+
+=item The DB module
+
+=item The regular expression code constructs:
+
+C<(?{ code })> and C<(??{ code })>
+
+=back
+
+=head1 Obsolete Diagnostics
+
+=over 4
+
+=item Character class syntax [: :] is reserved for future extensions
+
+(W) Within regular expression character classes ([]) the syntax beginning
+with "[:" and ending with ":]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[:" and ":\]".
+
+=item Ill-formed logical name |%s| in prime_env_iter
+
+(W) A warning peculiar to VMS. A logical name was encountered when preparing
+to iterate over %ENV which violates the syntactic rules governing logical
+names. Because it cannot be translated normally, it is skipped, and will not
+appear in %ENV. This may be a benign occurrence, as some software packages
+might directly modify logical name tables and introduce nonstandard names,
+or it may indicate that a logical name table has been corrupted.
+
+=item In string, @%s now must be written as \@%s
+
+The description of this error used to say:
+
+ (Someday it will simply assume that an unbackslashed @
+ interpolates an array.)
+
+That day has come, and this fatal error has been removed. It has been
+replaced by a non-fatal warning instead.
+See L</Arrays now always interpolate into double-quoted strings> for
+details.
+
+=item Probable precedence problem on %s
+
+(W) The compiler found a bareword where it expected a conditional,
+which often indicates that an || or && was parsed as part of the
+last argument of the previous construct, for example:
+
+ open FOO || die;
+
+=item regexp too big
+
+(F) The current implementation of regular expressions uses shorts as
+address offsets within a string. Unfortunately this means that if
+the regular expression compiles to longer than 32767, it'll blow up.
+Usually when you want a regular expression this big, there is a better
+way to do it with multiple statements. See L<perlre>.
+
+=item Use of "$$<digit>" to mean "${$}<digit>" is deprecated
+
+(D) Perl versions before 5.004 misinterpreted any type marker followed
+by "$" and a digit. For example, "$$0" was incorrectly taken to mean
+"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
+
+However, the developers of Perl 5.004 could not fix this bug completely,
+because at least two widely-used modules depend on the old meaning of
+"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
+old (broken) way inside strings; but it generates this message as a
+warning. And in Perl 5.005, this special treatment will cease.
+
+=back
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the
+articles recently posted to the comp.lang.perl.misc newsgroup.
+There may also be information at http://www.perl.com/perl/ , the Perl
+Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many
+contributions from The Perl Porters.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl570delta.pod b/Master/tlpkg/tlperl/lib/pods/perl570delta.pod
new file mode 100644
index 00000000000..dcc2f0f1889
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl570delta.pod
@@ -0,0 +1,899 @@
+=head1 NAME
+
+perl570delta - what's new for perl v5.7.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.6.0 release and
+the 5.7.0 release.
+
+=head1 Security Vulnerability Closed
+
+A potential security vulnerability in the optional suidperl component
+of Perl has been identified. suidperl is neither built nor installed
+by default. As of September the 2nd, 2000, the only known vulnerable
+platform is Linux, most likely all Linux distributions. CERT and
+various vendors have been alerted about the vulnerability.
+
+The problem was caused by Perl trying to report a suspected security
+exploit attempt using an external program, /bin/mail. On Linux
+platforms the /bin/mail program had an undocumented feature which
+when combined with suidperl gave access to a root shell, resulting in
+a serious compromise instead of reporting the exploit attempt. If you
+don't have /bin/mail, or if you have 'safe setuid scripts', or if
+suidperl is not installed, you are safe.
+
+The exploit attempt reporting feature has been completely removed from
+the Perl 5.7.0 release, so that particular vulnerability isn't there
+anymore. However, further security vulnerabilities are,
+unfortunately, always possible. The suidperl code is being reviewed
+and if deemed too risky to continue to be supported, it may be
+completely removed from future releases. In any case, suidperl should
+only be used by security experts who know exactly what they are doing
+and why they are using suidperl instead of some other solution such as
+sudo ( see http://www.courtesan.com/sudo/ ).
+
+=head1 Incompatible Changes
+
+=over 4
+
+=item *
+
+Arrays now always interpolate into double-quoted strings:
+constructs like "foo@bar" now always assume C<@bar> is an array,
+whether or not the compiler has seen use of C<@bar>.
+
+=item *
+
+The semantics of bless(REF, REF) were unclear and until someone proves
+it to make some sense, it is forbidden.
+
+=item *
+
+A reference to a reference now stringify as "REF(0x81485ec)" instead
+of "SCALAR(0x81485ec)" in order to be more consistent with the return
+value of ref().
+
+=item *
+
+The very dusty examples in the eg/ directory have been removed.
+Suggestions for new shiny examples welcome but the main issue is that
+the examples need to be documented, tested and (most importantly)
+maintained.
+
+=item *
+
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
+
+=item *
+
+The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
+recognised but now cause fatal errors. The previous behaviour of
+ignoring them by default and warning if requested was unacceptable
+since it, in a way, falsely promised that the features could be used.
+
+=item *
+
+The (bogus) escape sequences \8 and \9 now give an optional warning
+("Unrecognized escape passed through"). There is no need to \-escape
+any C<\w> character.
+
+=item *
+
+lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
+In future releases this may become a fatal error.
+
+=item *
+
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+
+=item *
+
+The regular expression captured submatches ($1, $2, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them.
+
+=item *
+
+The tr///C and tr///U features have been removed and will not return;
+the interface was a mistake. Sorry about that. For similar
+functionality, see pack('U0', ...) and pack('C0', ...).
+
+=back
+
+=head1 Core Enhancements
+
+=over 4
+
+=item *
+
+C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
+in multiple arguments.)
+
+=item *
+
+my __PACKAGE__ $obj now works.
+
+=item *
+
+C<no Module;> now works even if there is no "sub unimport" in the Module.
+
+=item *
+
+The numerical comparison operators return C<undef> if either operand
+is a NaN. Previously the behaviour was unspecified.
+
+=item *
+
+C<pack('U0a*', ...)> can now be used to force a string to UTF-8.
+
+=item *
+
+prototype(\&) is now available.
+
+=item *
+
+There is now an UNTIE method.
+
+=back
+
+=head1 Modules and Pragmata
+
+=head2 New Modules
+
+=over 4
+
+=item *
+
+File::Temp allows one to create temporary files and directories in an
+easy, portable, and secure way.
+
+=item *
+
+Storable gives persistence to Perl data structures by allowing the
+storage and retrieval of Perl data to and from files in a fast and
+compact binary format.
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
+
+=item *
+
+The following independently supported modules have been updated to
+newer versions from CPAN: CGI, CPAN, DB_File, File::Spec, Getopt::Long,
+the podlators bundle, Pod::LaTeX, Pod::Parser, Term::ANSIColor, Test.
+
+=item *
+
+Bug fixes and minor enhancements have been applied to B::Deparse,
+Data::Dumper, IO::Poll, IO::Socket::INET, Math::BigFloat,
+Math::Complex, Math::Trig, Net::protoent, the re pragma, SelfLoader,
+Sys::SysLog, Test::Harness, Text::Wrap, UNIVERSAL, and the warnings
+pragma.
+
+=item *
+
+The attributes::reftype() now works on tied arguments.
+
+=item *
+
+AutoLoader can now be disabled with C<no AutoLoader;>,
+
+=item *
+
+The English module can now be used without the infamous performance
+hit by saying
+
+ use English '-no_performance_hit';
+
+(Assuming, of course, that one doesn't need the troublesome variables
+C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
+C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
+
+=item *
+
+File::Find now has pre- and post-processing callbacks. It also
+correctly changes directories when chasing symbolic links. Callbacks
+(naughtily) exiting with "next;" instead of "return;" now work.
+
+=item *
+
+File::Glob::glob() renamed to File::Glob::bsd_glob() to avoid
+prototype mismatch with CORE::glob().
+
+=item *
+
+IPC::Open3 now allows the use of numeric file descriptors.
+
+=item *
+
+use lib now works identically to @INC. Removing directories
+with 'no lib' now works.
+
+=item *
+
+C<%INC> now localised in a Safe compartment so that use/require work.
+
+=item *
+
+The Shell module now has an OO interface.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+The Emacs perl mode (emacs/cperl-mode.el) has been updated to version
+4.31.
+
+=item *
+
+Perlbug is now much more robust. It also sends the bug report to
+perl.org, not perl.com.
+
+=item *
+
+The perlcc utility has been rewritten and its user interface (that is,
+command line) is much more like that of the Unix C compiler, cc.
+
+=item *
+
+The xsubpp utility for extension writers now understands POD
+documentation embedded in the *.xs files.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item *
+
+perl56delta details the changes between the 5.005 release and the
+5.6.0 release.
+
+=item *
+
+perldebtut is a Perl debugging tutorial.
+
+=item *
+
+perlebcdic contains considerations for running Perl on EBCDIC platforms.
+Note that unfortunately EBCDIC platforms that used to supported back in
+Perl 5.005 are still unsupported by Perl 5.7.0; the plan, however, is to
+bring them back to the fold.
+
+=item *
+
+perlnewmod tells about writing and submitting a new module.
+
+=item *
+
+perlposix-bc explains using Perl on the POSIX-BC platform
+(an EBCDIC mainframe platform).
+
+=item *
+
+perlretut is a regular expression tutorial.
+
+=item *
+
+perlrequick is a regular expressions quick-start guide.
+Yes, much quicker than perlretut.
+
+=item *
+
+perlutil explains the command line utilities packaged with the Perl
+distribution.
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+map() that changes the size of the list should now work faster.
+
+=item *
+
+sort() has been changed to use mergesort internally as opposed to the
+earlier quicksort. For very small lists this may result in slightly
+slower sorting times, but in general the speedup should be at least
+20%. Additional bonuses are that the worst case behaviour of sort()
+is now better (in computer science terms it now runs in time O(N log N),
+as opposed to quicksort's Theta(N**2) worst-case run time behaviour),
+and that sort() is now stable (meaning that elements with identical
+keys will stay ordered as they were before the sort).
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Generic Improvements
+
+=over 4
+
+=item *
+
+INSTALL now explains how you can configure Perl to use 64-bit
+integers even on non-64-bit platforms.
+
+=item *
+
+Policy.sh policy change: if you are reusing a Policy.sh file
+(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
+Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
+them will now be changed to the new prefix, /foo/bar. (Previously
+only $prefix changed.) If you do not like this new behaviour,
+specify prefix, siteprefix, and vendorprefix explicitly.
+
+=item *
+
+A new optional location for Perl libraries, otherlibdirs, is available.
+It can be used for example for vendor add-ons without disturbing Perl's
+own library directories.
+
+=item *
+
+In many platforms the vendor-supplied 'cc' is too stripped-down to
+build Perl (basically, 'cc' doesn't do ANSI C). If this seems
+to be the case and 'cc' does not seem to be the GNU C compiler
+'gcc', an automatic attempt is made to find and use 'gcc' instead.
+
+=item *
+
+gcc needs to closely track the operating system release to avoid
+build problems. If Configure finds that gcc was built for a different
+operating system release than is running, it now gives a clearly visible
+warning that there may be trouble ahead.
+
+=item *
+
+If binary compatibility with the 5.005 release is not wanted, Configure
+no longer suggests including the 5.005 modules in @INC.
+
+=item *
+
+Configure C<-S> can now run non-interactively.
+
+=item *
+
+configure.gnu now works with options with whitespace in them.
+
+=item *
+
+installperl now outputs everything to STDERR.
+
+=item *
+
+$Config{byteorder} is now computed dynamically (this is more robust
+with "fat binaries" where an executable image contains binaries for
+more than one binary platform.)
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Several debugger fixes: exit code now reflects the script exit code,
+condition C<"0"> now treated correctly, the C<d> command now checks
+line number, the C<$.> no longer gets corrupted, all debugger output now
+goes correctly to the socket if RemotePort is set.
+
+=item *
+
+C<*foo{FORMAT}> now works.
+
+=item *
+
+Lexical warnings now propagating correctly between scopes.
+
+=item *
+
+Line renumbering with eval and C<#line> now works.
+
+=item *
+
+Fixed numerous memory leaks, especially in eval "".
+
+=item *
+
+Modulus of unsigned numbers now works (4063328477 % 65535 used to
+return 27406, instead of 27047).
+
+=item *
+
+Some "not a number" warnings introduced in 5.6.0 eliminated to be
+more compatible with 5.005. Infinity is now recognised as a number.
+
+=item *
+
+our() variables will not cause "will not stay shared" warnings.
+
+=item *
+
+pack "Z" now correctly terminates the string with "\0".
+
+=item *
+
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused getpwent() to return every other entry.
+
+=item *
+
+printf() no longer resets the numeric locale to "C".
+
+=item *
+
+C<q(a\\b)> now parses correctly as C<'a\\b'>.
+
+=item *
+
+Printing quads (64-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
+
+=item *
+
+Regular expressions on references and overloaded scalars now work.
+
+=item *
+
+scalar() now forces scalar context even when used in void context.
+
+=item *
+
+sort() arguments are now compiled in the right wantarray context
+(they were accidentally using the context of the sort() itself).
+
+=item *
+
+Changed the POSIX character class C<[[:space:]]> to include the (very
+rare) vertical tab character. Added a new POSIX-ish character class
+C<[[:blank:]]> which stands for horizontal whitespace (currently,
+the space and the tab).
+
+=item *
+
+$AUTOLOAD, sort(), lock(), and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
+
+=item *
+
+Allow read-only string on left hand side of non-modifying tr///.
+
+=item *
+
+Several Unicode fixes (but still not perfect).
+
+=over 8
+
+=item *
+
+BOMs (byte order marks) in the beginning of Perl files
+(scripts, modules) should now be transparently skipped.
+UTF-16 (UCS-2) encoded Perl files should now be read correctly.
+
+=item *
+
+The character tables have been updated to Unicode 3.0.1.
+
+=item *
+
+chr() for values greater than 127 now create utf8 when under use
+utf8.
+
+=item *
+
+Comparing with utf8 data does not magically upgrade non-utf8 data into
+utf8.
+
+=item *
+
+C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
+
+=item *
+
+Concatenation with the C<.> operator or via variable interpolation,
+C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
+substitution with C<s///>, single-quoted UTF-8, should now work--in
+theory.
+
+=item *
+
+The C<tr///> operator now works I<slightly> better but is still rather
+broken. Note that the C<tr///CU> functionality has been removed (but
+see pack('U0', ...)).
+
+=item *
+
+vec() now refuses to deal with characters >255.
+
+=item *
+
+Zero entries were missing from the Unicode classes like C<IsDigit>.
+
+=back
+
+=item *
+
+UNIVERSAL::isa no longer caches methods incorrectly. (This broke
+the Tk extension with 5.6.0.)
+
+=back
+
+=head2 Platform Specific Changes and Fixes
+
+=over 4
+
+=item *
+
+BSDI 4.*
+
+Perl now works on post-4.0 BSD/OSes.
+
+=item *
+
+All BSDs
+
+Setting C<$0> now works (as much as possible; see perlvar for details).
+
+=item *
+
+Cygwin
+
+Numerous updates; currently synchronised with Cygwin 1.1.4.
+
+=item *
+
+EPOC
+
+EPOC update after Perl 5.6.0. See README.epoc.
+
+=item *
+
+FreeBSD 3.*
+
+Perl now works on post-3.0 FreeBSDs.
+
+=item *
+
+HP-UX
+
+README.hpux updated; C<Configure -Duse64bitall> now almost works.
+
+=item *
+
+IRIX
+
+Numerous compilation flag and hint enhancements; accidental mixing
+of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
+
+=item *
+
+Linux
+
+Long doubles should now work (see INSTALL).
+
+=item *
+
+Mac OS Classic
+
+Compilation of the standard Perl distribution in Mac OS Classic should
+now work if you have the Metrowerks development environment and the
+missing Mac-specific toolkit bits. Contact the macperl mailing list
+for details.
+
+=item *
+
+MPE/iX
+
+MPE/iX update after Perl 5.6.0. See README.mpeix.
+
+=item *
+
+NetBSD/sparc
+
+Perl now works on NetBSD/sparc.
+
+=item *
+
+OS/2
+
+Now works with usethreads (see INSTALL).
+
+=item *
+
+Solaris
+
+64-bitness using the Sun Workshop compiler now works.
+
+=item *
+
+Tru64 (aka Digital UNIX, aka DEC OSF/1)
+
+The operating system version letter now recorded in $Config{osvers}.
+Allow compiling with gcc (previously explicitly forbidden). Compiling
+with gcc still not recommended because buggy code results, even with
+gcc 2.95.2.
+
+=item *
+
+Unicos
+
+Fixed various alignment problems that lead into core dumps either
+during build or later; no longer dies on math errors at runtime;
+now using full quad integers (64 bits), previously was using
+only 46 bit integers for speed.
+
+=item *
+
+VMS
+
+chdir() now works better despite a CRT bug; now works with MULTIPLICITY
+(see INSTALL); now works with Perl's malloc.
+
+=item *
+
+Windows
+
+=over 8
+
+=item *
+
+accept() no longer leaks memory.
+
+=item *
+
+Better chdir() return value for a non-existent directory.
+
+=item *
+
+New %ENV entries now propagate to subprocesses.
+
+=item *
+
+$ENV{LIB} now used to search for libs under Visual C.
+
+=item *
+
+A failed (pseudo)fork now returns undef and sets errno to EAGAIN.
+
+=item *
+
+Allow REG_EXPAND_SZ keys in the registry.
+
+=item *
+
+Can now send() from all threads, not just the first one.
+
+=item *
+
+Fake signal handling reenabled, bugs and all.
+
+=item *
+
+Less stack reserved per thread so that more threads can run
+concurrently. (Still 16M per thread.)
+
+=item *
+
+C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
+(works better when perl is running as service).
+
+=item *
+
+Better UNC path handling under ithreads.
+
+=item *
+
+wait() and waitpid() now work much better.
+
+=item *
+
+winsock handle leak fixed.
+
+=back
+
+=back
+
+=head1 New or Changed Diagnostics
+
+All regular expression compilation error messages are now hopefully
+easier to understand both because the error message now comes before
+the failed regex and because the point of failure is now clearly
+marked.
+
+The various "opened only for", "on closed", "never opened" warnings
+drop the C<main::> prefix for filehandles in the C<main> package,
+for example C<STDIN> instead of <main::STDIN>.
+
+The "Unrecognized escape" warning has been extended to include C<\8>,
+C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+perlapi.pod (a companion to perlguts) now attempts to document the
+internal API.
+
+=item *
+
+You can now build a really minimal perl called microperl.
+Building microperl does not require even running Configure;
+C<make -f Makefile.micro> should be enough. Beware: microperl makes
+many assumptions, some of which may be too bold; the resulting
+executable may crash or otherwise misbehave in wondrous ways.
+For careful hackers only.
+
+=item *
+
+Added rsignal(), whichsig(), do_join() to the publicised API.
+
+=item *
+
+Made possible to propagate customised exceptions via croak()ing.
+
+=item *
+
+Added is_utf8_char(), is_utf8_string(), bytes_to_utf8(), and utf8_to_bytes().
+
+=item *
+
+Now xsubs can have attributes just like subs.
+
+=back
+
+=head1 Known Problems
+
+=head2 Unicode Support Still Far From Perfect
+
+We're working on it. Stay tuned.
+
+=head2 EBCDIC Still A Lost Platform
+
+The plan is to bring them back.
+
+=head2 Building Extensions Can Fail Because Of Largefiles
+
+Certain extensions like mod_perl and BSD::Resource are known to have
+issues with `largefiles', a change brought by Perl 5.6.0 in which file
+offsets default to 64 bits wide, where supported. Modules may fail to
+compile at all or compile and work incorrectly. Currently there is no
+good solution for the problem, but Configure now provides appropriate
+non-largefile ccflags, ldflags, libswanted, and libs in the %Config
+hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
+having problems can try configuring themselves without the
+largefileness. This is admittedly not a clean solution, and the
+solution may not even work at all. One potential failure is whether
+one can (or, if one can, whether it's a good idea) link together at
+all binaries with different ideas about file offsets, all this is
+platform-dependent.
+
+=head2 ftmp-security tests warn 'system possibly insecure'
+
+Don't panic. Read INSTALL 'make test' section instead.
+
+=head2 Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+
+If perl is configured with -Duse64bitall, the successful result of the
+subtest 10 of lib/posix may arrive before the successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+
+=head2 Long Doubles Still Don't Work In Solaris
+
+The experimental long double support is still very much so in Solaris.
+(Other platforms like Linux and Tru64 are beginning to solidify in
+this area.)
+
+=head2 Linux With Sfio Fails op/misc Test 48
+
+No known fix.
+
+=head2 Storable tests fail in some platforms
+
+If any Storable tests fail the use of Storable is not advisable.
+
+=over 4
+
+=item *
+
+Many Storable tests fail on AIX configured with 64 bit integers.
+
+So far unidentified problems break Storable in AIX if Perl is
+configured to use 64 bit integers. AIX in 32-bit mode works and
+other 64-bit platforms work with Storable.
+
+=item *
+
+DOS DJGPP may hang when testing Storable.
+
+=item *
+
+st-06compat fails in UNICOS and UNICOS/mk.
+
+This means that you cannot read old (pre-Storable-0.7) Storable images
+made in other platforms.
+
+=item *
+
+st-store.t and st-retrieve may fail with Compaq C 6.2 on OpenVMS Alpha 7.2.
+
+=back
+
+=head2 Threads Are Still Experimental
+
+Multithreading is still an experimental feature. Some platforms
+emit the following message for lib/thr5005
+
+ #
+ # This is a KNOWN FAILURE, and one of the reasons why threading
+ # is still an experimental feature. It is here to stop people
+ # from deploying threads in production. ;-)
+ #
+
+and another known thread-related warning is
+
+ pragma/overload......Unbalanced saves: 3 more saves than restores
+ panic: magic_mutexfree during global destruction.
+ ok
+ lib/selfloader.......Unbalanced saves: 3 more saves than restores
+ panic: magic_mutexfree during global destruction.
+ ok
+ lib/st-dclone........Unbalanced saves: 3 more saves than restores
+ panic: magic_mutexfree during global destruction.
+ ok
+
+=head2 The Compiler Suite Is Still Experimental
+
+The compiler suite is slowly getting better but is nowhere near
+working order yet. The backend part that has seen perhaps the most
+progress is the bytecode compiler.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ There may also be
+information at http://www.perl.com/perl/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
+from The Perl Porters and Perl Users submitting feedback and patches.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl571delta.pod b/Master/tlpkg/tlperl/lib/pods/perl571delta.pod
new file mode 100644
index 00000000000..be36e044066
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl571delta.pod
@@ -0,0 +1,1075 @@
+=head1 NAME
+
+perl571delta - what's new for perl v5.7.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.7.0 release and the
+5.7.1 release.
+
+(To view the differences between the 5.6.0 release and the 5.7.0
+release, see L<perl570delta>.)
+
+=head1 Security Vulnerability Closed
+
+(This change was already made in 5.7.0 but bears repeating here.)
+
+A potential security vulnerability in the optional suidperl component
+of Perl was identified in August 2000. suidperl is neither built nor
+installed by default. As of April 2001 the only known vulnerable
+platform is Linux, most likely all Linux distributions. CERT and
+various vendors and distributors have been alerted about the vulnerability.
+See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
+for more information.
+
+The problem was caused by Perl trying to report a suspected security
+exploit attempt using an external program, /bin/mail. On Linux
+platforms the /bin/mail program had an undocumented feature which
+when combined with suidperl gave access to a root shell, resulting in
+a serious compromise instead of reporting the exploit attempt. If you
+don't have /bin/mail, or if you have 'safe setuid scripts', or if
+suidperl is not installed, you are safe.
+
+The exploit attempt reporting feature has been completely removed from
+all the Perl 5.7 releases (and will be gone also from the maintenance
+release 5.6.1), so that particular vulnerability isn't there anymore.
+However, further security vulnerabilities are, unfortunately, always
+possible. The suidperl code is being reviewed and if deemed too risky
+to continue to be supported, it may be completely removed from future
+releases. In any case, suidperl should only be used by security
+experts who know exactly what they are doing and why they are using
+suidperl instead of some other solution such as sudo
+( see http://www.courtesan.com/sudo/ ).
+
+=head1 Incompatible Changes
+
+=over 4
+
+=item *
+
+Although "you shouldn't do that", it was possible to write code that
+depends on Perl's hashed key order (Data::Dumper does this). The new
+algorithm "One-at-a-Time" produces a different hashed key order.
+More details are in L</"Performance Enhancements">.
+
+=item *
+
+The list of filenames from glob() (or <...>) is now by default sorted
+alphabetically to be csh-compliant. (bsd_glob() does still sort platform
+natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.)
+
+=back
+
+=head1 Core Enhancements
+
+=head2 AUTOLOAD Is Now Lvaluable
+
+AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
+to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+
+=head2 PerlIO is Now The Default
+
+=over 4
+
+=item *
+
+IO is now by default done via PerlIO rather than system's "stdio".
+PerlIO allows "layers" to be "pushed" onto a file handle to alter the
+handle's behaviour. Layers can be specified at open time via 3-arg
+form of open:
+
+ open($fh,'>:crlf :utf8', $path) || ...
+
+or on already opened handles via extended C<binmode>:
+
+ binmode($fh,':encoding(iso-8859-7)');
+
+The built-in layers are: unix (low level read/write), stdio (as in
+previous Perls), perlio (re-implementation of stdio buffering in a
+portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
+but available on any platform). A mmap layer may be available if
+platform supports it (mostly Unixes).
+
+Layers to be applied by default may be specified via the 'open' pragma.
+
+See L</"Installation and Configuration Improvements"> for the effects
+of PerlIO on your architecture name.
+
+=item *
+
+File handles can be marked as accepting Perl's internal encoding of Unicode
+(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
+
+ open($fh,">:utf8","Uni.txt");
+
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF-8 what you will be getting but instead
+UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
+http://www.unicode.org/unicode/reports/tr16/ for more information.
+In future releases this naming may change.
+
+=item *
+
+File handles can translate character encodings from/to Perl's internal
+Unicode form on read/write via the ":encoding()" layer.
+
+=item *
+
+File handles can be opened to "in memory" files held in Perl scalars via:
+
+ open($fh,'>', \$variable) || ...
+
+=item *
+
+Anonymous temporary files are available without need to
+'use FileHandle' or other module via
+
+ open($fh,"+>", undef) || ...
+
+That is a literal undef, not an undefined value.
+
+=item *
+
+The list form of C<open> is now implemented for pipes (at least on Unix):
+
+ open($fh,"-|", 'cat', '/etc/motd')
+
+creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in
+the child process.
+
+=item *
+
+The following builtin functions are now overridable: chop(), chomp(),
+each(), keys(), pop(), push(), shift(), splice(), unshift().
+
+=item *
+
+Formats now support zero-padded decimal fields.
+
+=item *
+
+Perl now tries internally to use integer values in numeric conversions
+and basic arithmetics (+ - * /) if the arguments are integers, and
+tries also to keep the results stored internally as integers.
+This change leads into often slightly faster and always less lossy
+arithmetics. (Previously Perl always preferred floating point numbers
+in its math.)
+
+=item *
+
+The printf() and sprintf() now support parameter reordering using the
+C<%\d+\$> and C<*\d+\$> syntaxes. For example
+
+ print "%2\$s %1\$s\n", "foo", "bar";
+
+will print "bar foo\n"; This feature helps in writing
+internationalised software.
+
+=item *
+
+Unicode in general should be now much more usable. Unicode can be
+used in hash keys, Unicode in regular expressions should work now,
+Unicode in tr/// should work now (though tr/// seems to be a
+particularly tricky to get right, so you have been warned)
+
+=item *
+
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.1. For more information, see http://www.unicode.org/ ,
+and http://www.unicode.org/unicode/reports/tr27/
+
+For developers interested in enhancing Perl's Unicode capabilities:
+almost all the UCD files are included with the Perl distribution in
+the lib/unicode subdirectory. The most notable omission, for space
+considerations, is the Unihan database.
+
+=item *
+
+The Unicode character classes \p{Blank} and \p{SpacePerl} have been
+added. "Blank" is like C isblank(), that is, it contains only
+"horizontal whitespace" (the space character is, the newline isn't),
+and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
+isn't, since that includes the vertical tabulator character, whereas
+C<\s> doesn't.)
+
+=back
+
+=head2 Signals Are Now Safe
+
+Perl used to be fragile in that signals arriving at inopportune moments
+could corrupt Perl's internal state.
+
+=head1 Modules and Pragmata
+
+=head2 New Modules
+
+=over 4
+
+=item *
+
+B::Concise, by Stephen McCamant, is a new compiler backend for
+walking the Perl syntax tree, printing concise info about ops.
+The output is highly customisable.
+
+See L<B::Concise> for more information.
+
+=item *
+
+Class::ISA, by Sean Burke, for reporting the search path for a
+class's ISA tree, has been added.
+
+See L<Class::ISA> for more information.
+
+=item *
+
+Cwd has now a split personality: if possible, an extension is used,
+(this will hopefully be both faster and more secure and robust) but
+if not possible, the familiar Perl library implementation is used.
+
+=item *
+
+Digest, a frontend module for calculating digests (checksums),
+from Gisle Aas, has been added.
+
+See L<Digest> for more information.
+
+=item *
+
+Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas,
+has been added.
+
+ use Digest::MD5 'md5_hex';
+
+ $digest = md5_hex("Thirsty Camel");
+
+ print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
+
+NOTE: the MD5 backward compatibility module is deliberately not
+included since its use is discouraged.
+
+See L<Digest::MD5> for more information.
+
+=item *
+
+Encode, by Nick Ing-Simmons, provides a mechanism to translate
+between different character encodings. Support for Unicode,
+ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are
+compiled in to the module. Several other encodings (like Japanese,
+Chinese, and MacIntosh encodings) are included and will be loaded at
+runtime.
+
+Any encoding supported by Encode module is also available to the
+":encoding()" layer if PerlIO is used.
+
+See L<Encode> for more information.
+
+=item *
+
+Filter::Simple is an easy-to-use frontend to Filter::Util::Call,
+from Damian Conway.
+
+ # in MyFilter.pm:
+
+ package MyFilter;
+
+ use Filter::Simple sub {
+ while (my ($from, $to) = splice @_, 0, 2) {
+ s/$from/$to/g;
+ }
+ };
+
+ 1;
+
+ # in user's code:
+
+ use MyFilter qr/red/ => 'green';
+
+ print "red\n"; # this code is filtered, will print "green\n"
+ print "bored\n"; # this code is filtered, will print "bogreen\n"
+
+ no MyFilter;
+
+ print "red\n"; # this code is not filtered, will print "red\n"
+
+See L<Filter::Simple> for more information.
+
+=item *
+
+Filter::Util::Call, by Paul Marquess, provides you with the
+framework to write I<Source Filters> in Perl. For most uses
+the frontend Filter::Simple is to be preferred.
+See L<Filter::Util::Call> for more information.
+
+=item *
+
+Locale::Constants, Locale::Country, Locale::Currency, and Locale::Language,
+from Neil Bowers, have been added. They provide the codes for various
+locale standards, such as "fr" for France, "usd" for US Dollar, and
+"jp" for Japanese.
+
+ use Locale::Country;
+
+ $country = code2country('jp'); # $country gets 'Japan'
+ $code = country2code('Norway'); # $code gets 'no'
+
+See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
+and L<Locale::Language> for more information.
+
+=item *
+
+MIME::Base64, by Gisle Aas, allows you to encode data in base64.
+
+ use MIME::Base64;
+
+ $encoded = encode_base64('Aladdin:open sesame');
+ $decoded = decode_base64($encoded);
+
+ print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
+
+See L<MIME::Base64> for more information.
+
+=item *
+
+MIME::QuotedPrint, by Gisle Aas, allows you to encode data in
+quoted-printable encoding.
+
+ use MIME::QuotedPrint;
+
+ $encoded = encode_qp("Smiley in Unicode: \x{263a}");
+ $decoded = decode_qp($encoded);
+
+ print $encoded, "\n"; # "Smiley in Unicode: =263A"
+
+MIME::QuotedPrint has been enhanced to provide the basic methods
+necessary to use it with PerlIO::Via as in :
+
+ use MIME::QuotedPrint;
+ open($fh,">Via(MIME::QuotedPrint)",$path)
+
+See L<MIME::QuotedPrint> for more information.
+
+=item *
+
+PerlIO::Scalar, by Nick Ing-Simmons, provides the implementation of
+IO to "in memory" Perl scalars as discussed above. It also serves as
+an example of a loadable layer. Other future possibilities include
+PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar> for more
+information.
+
+=item *
+
+PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
+PerlIO layer functionality provided by a class (typically implemented
+in perl code).
+
+ use MIME::QuotedPrint;
+ open($fh,">Via(MIME::QuotedPrint)",$path)
+
+This will automatically convert everything output to C<$fh>
+to Quoted-Printable. See L<PerlIO::Via> for more information.
+
+=item *
+
+Pod::Text::Overstrike, by Joe Smith, has been added.
+It converts POD data to formatted overstrike text.
+See L<Pod::Text::Overstrike> for more information.
+
+=item *
+
+Switch from Damian Conway has been added. Just by saying
+
+ use Switch;
+
+you have C<switch> and C<case> available in Perl.
+
+ use Switch;
+
+ switch ($val) {
+
+ case 1 { print "number 1" }
+ case "a" { print "string a" }
+ case [1..10,42] { print "number in list" }
+ case (@array) { print "number in list" }
+ case /\w+/ { print "pattern" }
+ case qr/\w+/ { print "pattern" }
+ case (%hash) { print "entry in hash" }
+ case (\%hash) { print "entry in hash" }
+ case (\&sub) { print "arg to subroutine" }
+ else { print "previous case not true" }
+ }
+
+See L<Switch> for more information.
+
+=item *
+
+Text::Balanced from Damian Conway has been added, for
+extracting delimited text sequences from strings.
+
+ use Text::Balanced 'extract_delimited';
+
+ ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
+
+$a will be "'never say never'", $b will be ', he never said'.
+
+In addition to extract_delimited() there are also extract_bracketed(),
+extract_quotelike(), extract_codeblock(), extract_variable(),
+extract_tagged(), extract_multiple(), gen_delimited_pat(), and
+gen_extract_tagged(). With these you can implement rather advanced
+parsing algorithms. See L<Text::Balanced> for more information.
+
+=item *
+
+Tie::RefHash::Nestable, by Edward Avis, allows storing hash references
+(unlike the standard Tie::RefHash) The module is contained within
+Tie::RefHash.
+
+=item *
+
+XS::Typemap, by Tim Jenness, is a test extension that exercises XS
+typemaps. Nothing gets installed but for extension writers the code
+is worth studying.
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
+
+=item *
+
+B::Deparse should be now more robust. It still far from providing a full
+round trip for any random piece of Perl code, though, and is under active
+development: expect more robustness in 5.7.2.
+
+=item *
+
+Class::Struct can now define the classes in compile time.
+
+=item *
+
+Math::BigFloat has undergone much fixing, and in addition the fmod()
+function now supports modulus operations.
+
+( The fixed Math::BigFloat module is also available in CPAN for those
+who can't upgrade their Perl: http://www.cpan.org/authors/id/J/JP/JPEACOCK/ )
+
+=item *
+
+Devel::Peek now has an interface for the Perl memory statistics
+(this works only if you are using perl's malloc, and if you have
+compiled with debugging).
+
+=item *
+
+IO::Socket has now atmark() method, which returns true if the socket
+is positioned at the out-of-band mark. The method is also exportable
+as a sockatmark() function.
+
+=item *
+
+IO::Socket::INET has support for ReusePort option (if your platform
+supports it). The Reuse option now has an alias, ReuseAddr. For clarity
+you may want to prefer ReuseAddr.
+
+=item *
+
+Net::Ping has been enhanced. There is now "external" protocol which
+uses Net::Ping::External module which runs external ping(1) and parses
+the output. An alpha version of Net::Ping::External is available in
+CPAN and in 5.7.2 the Net::Ping::External may be integrated to Perl.
+
+=item *
+
+The C<open> pragma allows layers other than ":raw" and ":crlf" when
+using PerlIO.
+
+=item *
+
+POSIX::sigaction() is now much more flexible and robust.
+You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
+handlers, installing new handlers was not atomic.
+
+=item *
+
+The Test module has been significantly enhanced. Its use is
+greatly recommended for module writers.
+
+=item *
+
+The utf8:: name space (as in the pragma) provides various
+Perl-callable functions to provide low level access to Perl's
+internal Unicode representation. At the moment only length()
+has been implemented.
+
+=back
+
+The following modules have been upgraded from the versions at CPAN:
+CPAN, CGI, DB_File, File::Temp, Getopt::Long, Pod::Man, Pod::Text,
+Storable, Text-Tabs+Wrap.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
+( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
+reasonably fast while producing a much better spread of values than
+the old hashing algorithm (originally by Chris Torek, later tweaked by
+Ilya Zakharevich). Hash values output from the algorithm on a hash of
+all 3-char printable ASCII keys comes much closer to passing the
+DIEHARD random number generation tests. According to perlbench, this
+change has not affected the overall speed of Perl.
+
+=item *
+
+unshift() should now be noticeably faster.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+h2xs now produces template README.
+
+=item *
+
+s2p has been completely rewritten in Perl. (It is in fact a full
+implementation of sed in Perl.)
+
+=item *
+
+xsubpp now supports OUT keyword.
+
+=back
+
+=head1 New Documentation
+
+=head2 perlclib
+
+Internal replacements for standard C library functions.
+(Interesting only for extension writers and Perl core hackers.)
+
+=head2 perliol
+
+Internals of PerlIO with layers.
+
+=head2 README.aix
+
+Documentation on compiling Perl on AIX has been added. AIX has
+several different C compilers and getting the right patch level
+is essential. On install README.aix will be installed as L<perlaix>.
+
+=head2 README.bs2000
+
+Documentation on compiling Perl on the POSIX-BC platform (an EBCDIC
+mainframe environment) has been added.
+
+This was formerly known as README.posix-bc but the name was considered
+to be too confusing (it has nothing to do with the POSIX module or the
+POSIX standard). On install README.bs2000 will be installed as L<perlbs2000>.
+
+=head2 README.macos
+
+In perl 5.7.1 (and in the 5.6.1) the MacPerl sources have been
+synchronised with the standard Perl sources. To compile MacPerl
+some additional steps are required, and this file documents those
+steps. On install README.macos will be installed as L<perlmacos>.
+
+=head2 README.mpeix
+
+The README.mpeix has been podified, which means that this information
+about compiling and using Perl on the MPE/iX miniframe platform will
+be installed as L<perlmpeix>.
+
+=head2 README.solaris
+
+README.solaris has been created and Solaris wisdom from elsewhere
+in the Perl documentation has been collected there. On install
+README.solaris will be installed as L<perlsolaris>.
+
+=head2 README.vos
+
+The README.vos has been podified, which means that this information
+about compiling and using Perl on the Stratus VOS miniframe platform
+will be installed as L<perlvos>.
+
+=head2 Porting/repository.pod
+
+Documentation on how to use the Perl source repository has been added.
+
+=head1 Installation and Configuration Improvements
+
+=over 4
+
+=item *
+
+Because PerlIO is now the default on most platforms, "-perlio" doesn't
+get appended to the $Config{archname} (also known as $^O) anymore.
+Instead, if you explicitly choose not to use perlio (Configure command
+line option -Uuseperlio), you will get "-stdio" appended.
+
+=item *
+
+Another change related to the architecture name is that "-64all"
+(-Duse64bitall, or "maximally 64-bit") is appended only if your
+pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
+
+=item *
+
+APPLLIB_EXP, a less-know configuration-time definition, has been
+documented. It can be used to prepend site-specific directories
+to Perl's default search path (@INC), see INSTALL for information.
+
+=item *
+
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
+
+=item *
+
+If you are on IRIX or Tru64 platforms, new profiling/debugging options
+have been added, see L<perlhack> for more information about pixie and
+Third Degree.
+
+=back
+
+=head2 New Or Improved Platforms
+
+For the list of platforms known to support Perl,
+see L<perlport/"Supported Platforms">.
+
+=over 4
+
+=item *
+
+AIX dynamic loading should be now better supported.
+
+=item *
+
+After a long pause, AmigaOS has been verified to be happy with Perl.
+
+=item *
+
+EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA)
+have been regained. Many test suite tests still fail and the
+co-existence of Unicode and EBCDIC isn't quite settled, but the
+situation is much better than with Perl 5.6. See L<perlos390>,
+L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
+
+=item *
+
+Building perl with -Duseithreads or -Duse5005threads now works under
+HP-UX 10.20 (previously it only worked under 10.30 or later). You will
+need a thread library package installed. See README.hpux.
+
+=item *
+
+Mac OS Classic (MacPerl has of course been available since
+perl 5.004 but now the source code bases of standard Perl
+and MacPerl have been synchronised)
+
+=item *
+
+NCR MP-RAS is now supported.
+
+=item *
+
+NonStop-UX is now supported.
+
+=item *
+
+Amdahl UTS is now supported.
+
+=item *
+
+z/OS (formerly known as OS/390, formerly known as MVS OE) has now
+support for dynamic loading. This is not selected by default,
+however, you must specify -Dusedl in the arguments of Configure.
+
+=back
+
+=head2 Generic Improvements
+
+=over 4
+
+=item *
+
+Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
+when building the Perl binary. The only exception to this is SunOS 4.x,
+which needs them.
+
+=item *
+
+Some new Configure symbols, useful for extension writers:
+
+=over 8
+
+=item d_cmsghdr
+
+For struct cmsghdr.
+
+=item d_fcntl_can_lock
+
+Whether fcntl() can be used for file locking.
+
+=item d_fsync
+
+=item d_getitimer
+
+=item d_getpagsz
+
+For getpagesize(), though you should prefer POSIX::sysconf(_SC_PAGE_SIZE))
+
+=item d_msghdr_s
+
+For struct msghdr.
+
+=item need_va_copy
+
+Whether one needs to use Perl_va_copy() to copy varargs.
+
+=item d_readv
+
+=item d_recvmsg
+
+=item d_sendmsg
+
+=item sig_size
+
+The number of elements in an array needed to hold all the available signals.
+
+=item d_sockatmark
+
+=item d_strtoq
+
+=item d_u32align
+
+Whether one needs to access character data aligned by U32 sized pointers.
+
+=item d_ualarm
+
+=item d_usleep
+
+=back
+
+=item *
+
+Removed Configure symbols: the PDP-11 memory model settings: huge,
+large, medium, models.
+
+=item *
+
+SOCKS support is now much more robust.
+
+=item *
+
+If your file system supports symbolic links you can build Perl outside
+of the source directory by
+
+ mkdir perl/build/directory
+ cd perl/build/directory
+ sh /path/to/perl/source/Configure -Dmksymlinks ...
+
+This will create in perl/build/directory a tree of symbolic links
+pointing to files in /path/to/perl/source. The original files are left
+unaffected. After Configure has finished you can just say
+
+ make all test
+
+and Perl will be built and tested, all in perl/build/directory.
+
+=back
+
+=head1 Selected Bug Fixes
+
+Numerous memory leaks and uninitialized memory accesses have been hunted down.
+Most importantly anonymous subs used to leak quite a bit.
+
+=over 4
+
+=item *
+
+chop(@list) in list context returned the characters chopped in
+reverse order. This has been reversed to be in the right order.
+
+=item *
+
+The order of DESTROYs has been made more predictable.
+
+=item *
+
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
+
+=item *
+
+Attributes (like :shared) didn't work with our().
+
+=item *
+
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options.
+
+=item *
+
+The tainting behaviour of sprintf() has been rationalized. It does
+not taint the result of floating point formats anymore, making the
+behaviour consistent with that of string interpolation.
+
+=item *
+
+All but the first argument of the IO syswrite() method are now optional.
+
+=item *
+
+Tie::ARRAY SPLICE method was broken.
+
+=item *
+
+vec() now tries to work with characters <= 255 when possible, but it leaves
+higher character values in place. In that case, if vec() was used to modify
+the string, it is no longer considered to be utf8-encoded.
+
+=back
+
+=head2 Platform Specific Changes and Fixes
+
+=over 4
+
+=item *
+
+Linux previously had problems related to sockaddrlen when using
+accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname().
+
+=item *
+
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+
+=item *
+
+Windows
+
+=over 8
+
+=item *
+
+Borland C++ v5.5 is now a supported compiler that can build Perl.
+However, the generated binaries continue to be incompatible with those
+generated by the other supported compilers (GCC and Visual C++).
+
+=item *
+
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed.
+
+=item *
+
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+
+=item *
+
+HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html
+
+=item *
+
+The makefiles now provide a single switch to bulk-enable all the features
+enabled in ActiveState ActivePerl (a popular binary distribution).
+
+=back
+
+=back
+
+=head1 New or Changed Diagnostics
+
+Two new debugging options have been added: if you have compiled your
+Perl with debugging, you can use the -DT and -DR options to trace
+tokenising and to add reference counts to displaying variables,
+respectively.
+
+=over 4
+
+=item *
+
+If an attempt to use a (non-blessed) reference as an array index
+is made, a warning is given.
+
+=item *
+
+C<push @a;> and C<unshift @a;> (with no values to push or unshift)
+now give a warning. This may be a problem for generated and eval'ed
+code.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv().
+For the full list of the available APIs see L<perlapi>.
+
+=item *
+
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
+
+=item *
+
+Perl now uses system malloc instead of Perl malloc on all 64-bit
+platforms, and even in some not-always-64-bit platforms like AIX,
+IRIX, and Solaris. This change breaks backward compatibility but
+Perl's malloc has problems with large address spaces and also the
+speed of vendors' malloc is generally better in large address space
+machines (Perl's malloc is mostly tuned for space).
+
+=back
+
+=head1 New Tests
+
+Many new tests have been added. The most notable is probably the
+lib/1_compile: it is very notable because running it takes quite a
+long time. It test compiles all the Perl modules in the distribution.
+Please be patient.
+
+=head1 Known Problems
+
+Note that unlike other sections in this document (which describe
+changes since 5.7.0) this section is cumulative containing known
+problems for all the 5.7 releases.
+
+=head2 AIX vac 5.0.0.0 May Produce Buggy Code For Perl
+
+The AIX C compiler vac version 5.0.0.0 may produce buggy code,
+resulting in few random tests failing, but when the failing tests
+are run by hand, they succeed. We suggest upgrading to at least
+vac version 5.0.1.0, that has been known to compile Perl correctly.
+"lslpp -L|grep vac.C" will tell you the vac version.
+
+=head2 lib/ftmp-security tests warn 'system possibly insecure'
+
+Don't panic. Read INSTALL 'make test' section instead.
+
+=head2 lib/io_multihomed Fails In LP64-Configured HP-UX
+
+The lib/io_multihomed test may hang in HP-UX if Perl has been
+configured to be 64-bit. Because other 64-bit platforms do not hang in
+this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
+test attempts to create and connect to "multihomed" sockets (sockets
+which have multiple IP addresses).
+
+=head2 Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+
+If perl is configured with -Duse64bitall, the successful result of the
+subtest 10 of lib/posix may arrive before the successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+
+=head2 lib/b test 19
+
+The test fails on various platforms (PA64 and IA64 are known), but the
+exact cause is still being investigated.
+
+=head2 Linux With Sfio Fails op/misc Test 48
+
+No known fix.
+
+=head2 sigaction test 13 in VMS
+
+The test is known to fail; whether it's because of VMS of because
+of faulty test is not known.
+
+=head2 sprintf tests 129 and 130
+
+The op/sprintf tests 129 and 130 are known to fail on some platforms.
+Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
+The failing platforms do not comply with the ANSI C Standard, line
+19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
+something else than "1" and "-1" when formatting 0.6 and -0.6 using
+the printf format "%.0f", most often they produce "0" and "-0".)
+
+=head2 Failure of Thread tests
+
+The subtests 19 and 20 of lib/thr5005.t test are known to fail due to
+fundamental problems in the 5.005 threading implementation. These are
+not new failures--Perl 5.005_0x has the same bugs, but didn't have
+these tests. (Note that support for 5.005-style threading remains
+experimental.)
+
+=head2 Localising a Tied Variable Leaks Memory
+
+ use Tie::Hash;
+ tie my %tie_hash => 'Tie::StdHash';
+
+ ...
+
+ local($tie_hash{Foo}) = 1; # leaks
+
+Code like the above is known to leak memory every time the local()
+is executed.
+
+=head2 Self-tying of Arrays and Hashes Is Forbidden
+
+Self-tying of arrays and hashes is broken in rather deep and
+hard-to-fix ways. As a stop-gap measure to avoid people from getting
+frustrated at the mysterious results (core dumps, most often) it is
+for now forbidden (you will get a fatal error even from an attempt).
+
+=head2 Building Extensions Can Fail Because Of Largefiles
+
+Some extensions like mod_perl are known to have issues with
+`largefiles', a change brought by Perl 5.6.0 in which file offsets
+default to 64 bits wide, where supported. Modules may fail to compile
+at all or compile and work incorrectly. Currently there is no good
+solution for the problem, but Configure now provides appropriate
+non-largefile ccflags, ldflags, libswanted, and libs in the %Config
+hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
+having problems can try configuring themselves without the
+largefileness. This is admittedly not a clean solution, and the
+solution may not even work at all. One potential failure is whether
+one can (or, if one can, whether it's a good idea) link together at
+all binaries with different ideas about file offsets, all this is
+platform-dependent.
+
+=head2 The Compiler Suite Is Still Experimental
+
+The compiler suite is slowly getting better but is nowhere near
+working order yet.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ There may also be
+information at http://www.perl.com/perl/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
+from The Perl Porters and Perl Users submitting feedback and patches.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl572delta.pod b/Master/tlpkg/tlperl/lib/pods/perl572delta.pod
new file mode 100644
index 00000000000..21585edc4e0
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl572delta.pod
@@ -0,0 +1,831 @@
+=head1 NAME
+
+perl572delta - what's new for perl v5.7.2
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.7.1 release and the
+5.7.2 release.
+
+(To view the differences between the 5.6.0 release and the 5.7.0
+release, see L<perl570delta>. To view the differences between the
+5.7.0 release and the 5.7.1 release, see L<perl571delta>.)
+
+=head1 Security Vulnerability Closed
+
+(This change was already made in 5.7.0 but bears repeating here.)
+
+A security vulnerability affecting all Perl versions prior to 5.6.1
+was found in August 2000. The vulnerability does not affect default
+installations and as far as is known affects only the Linux platform.
+
+You should upgrade your Perl to 5.6.1 as soon as possible. Patches
+for earlier releases exist but using the patches require full
+recompilation from the source code anyway, so 5.6.1 is your best
+choice.
+
+See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
+for more information.
+
+=head1 Incompatible Changes
+
+=head2 64-bit platforms and malloc
+
+If your pointers are 64 bits wide, the Perl malloc is no more being
+used because it simply does not work with 8-byte pointers. Also,
+usually the system malloc on such platforms are much better optimized
+for such large memory models than the Perl malloc.
+
+=head2 AIX Dynaloading
+
+The AIX dynaloading now uses in AIX releases 4.3 and newer the native
+dlopen interface of AIX instead of the old emulated interface. This
+change will probably break backward compatibility with compiled
+modules. The change was made to make Perl more compliant with other
+applications like modperl which are using the AIX native interface.
+
+=head2 Socket Extension Dynamic in VMS
+
+The Socket extension is now dynamically loaded instead of being
+statically built in. This may or may not be a problem with ancient
+TCP/IP stacks of VMS: we do not know since we weren't able to test
+Perl in such configurations.
+
+=head2 Different Definition of the Unicode Character Classes \p{In...}
+
+As suggested by the Unicode consortium, the Unicode character classes
+now prefer I<scripts> as opposed to I<blocks> (as defined by Unicode);
+in Perl, when the C<\p{In....}> and the C<\p{In....}> regular expression
+constructs are used. This has changed the definition of some of those
+character classes.
+
+The difference between scripts and blocks is that scripts are the
+glyphs used by a language or a group of languages, while the blocks
+are more artificial groupings of 256 characters based on the Unicode
+numbering.
+
+In general this change results in more inclusive Unicode character
+classes, but changes to the other direction also do take place:
+for example while the script C<Latin> includes all the Latin
+characters and their various diacritic-adorned versions, it
+does not include the various punctuation or digits (since they
+are not solely C<Latin>).
+
+Changes in the character class semantics may have happened if a script
+and a block happen to have the same name, for example C<Hebrew>.
+In such cases the script wins and C<\p{InHebrew}> now means the script
+definition of Hebrew. The block definition in still available,
+though, by appending C<Block> to the name: C<\p{InHebrewBlock}> means
+what C<\p{InHebrew}> meant in perl 5.6.0. For the full list
+of affected character classes, see L<perlunicode/Blocks>.
+
+=head2 Deprecations
+
+The current user-visible implementation of pseudo-hashes (the weird
+use of the first array element) is deprecated starting from Perl 5.8.0
+and will be removed in Perl 5.10.0, and the feature will be
+implemented differently. Not only is the current interface rather
+ugly, but the current implementation slows down normal array and hash
+use quite noticeably. The C<fields> pragma interface will remain
+available.
+
+The syntaxes C<< @a->[...] >> and C<< @h->{...} >> have now been deprecated.
+
+The suidperl is also considered to be too much a risk to continue
+maintaining and the suidperl code is likely to be removed in a future
+release.
+
+The C<package;> syntax (C<package> without an argument has been
+deprecated. Its semantics were never that clear and its
+implementation even less so. If you have used that feature to
+disallow all but fully qualified variables, C<use strict;> instead.
+
+The chdir(undef) and chdir('') behaviors to match chdir() has been
+deprecated. In future versions, chdir(undef) and chdir('') will
+simply fail.
+
+=head1 Core Enhancements
+
+In general a lot of fixing has happened in the area of Perl's
+understanding of numbers, both integer and floating point. Since in
+many systems the standard number parsing functions like C<strtoul()>
+and C<atof()> seem to have bugs, Perl tries to work around their
+deficiencies. This results hopefully in more accurate numbers.
+
+=over 4
+
+=item *
+
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+B<between digits>.
+
+=item *
+
+GMAGIC (right-hand side magic) could in many cases such as string
+concatenation be invoked too many times.
+
+=item *
+
+Lexicals I: lexicals outside an eval "" weren't resolved
+correctly inside a subroutine definition inside the eval "" if they
+were not already referenced in the top level of the eval""ed code.
+
+=item *
+
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
+
+=item *
+
+Lvalue subroutines can now return C<undef> in list context.
+
+=item *
+
+The C<op_clear> and C<op_null> are now exported.
+
+=item *
+
+A new special regular expression variable has been introduced:
+C<$^N>, which contains the most-recently closed group (submatch).
+
+=item *
+
+L<utime> now supports C<utime undef, undef, @files> to change the
+file timestamps to the current time.
+
+=item *
+
+The Perl parser has been stress tested using both random input and
+Markov chain input.
+
+=item *
+
+C<eval "v200"> now works.
+
+=item *
+
+VMS now works under PerlIO.
+
+=item *
+
+END blocks are now run even if you exit/die in a BEGIN block.
+The execution of END blocks is now controlled by
+PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
+behaviour for perl embedders. This will default in 5.10. See
+L<perlembed>.
+
+=back
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Distributions
+
+=over 4
+
+=item *
+
+L<Attribute::Handlers> - Simpler definition of attribute handlers
+
+=item *
+
+L<ExtUtils::Constant> - generate XS code to import C header constants
+
+=item *
+
+L<I18N::Langinfo> - query locale information
+
+=item *
+
+L<I18N::LangTags> - functions for dealing with RFC3066-style language tags
+
+=item *
+
+L<libnet> - a collection of perl5 modules related to network programming
+
+Perl installation leaves libnet unconfigured, use F<libnetcfg> to configure.
+
+=item *
+
+L<List::Util> - selection of general-utility list subroutines
+
+=item *
+
+L<Locale::Maketext> - framework for localization
+
+=item *
+
+L<Memoize> - Make your functions faster by trading space for time
+
+=item *
+
+L<NEXT> - pseudo-class for method redispatch
+
+=item *
+
+L<Scalar::Util> - selection of general-utility scalar subroutines
+
+=item *
+
+L<Test::More> - yet another framework for writing test scripts
+
+=item *
+
+L<Test::Simple> - Basic utilities for writing tests
+
+=item *
+
+L<Time::HiRes> - high resolution ualarm, usleep, and gettimeofday
+
+=item *
+
+L<Time::Piece> - Object Oriented time objects
+
+(Previously known as L<Time::Object>.)
+
+=item *
+
+L<Time::Seconds> - a simple API to convert seconds to other date values
+
+=item *
+
+L<UnicodeCD> - Unicode Character Database
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
+
+=item *
+
+L<B::Deparse> module has been significantly enhanced. It now
+can deparse almost all of the standard test suite (so that the
+tests still succeed). There is a make target "test.deparse"
+for trying this out.
+
+=item *
+
+L<Class::Struct> now assigns the array/hash element if the accessor
+is called with an array/hash element as the B<sole> argument.
+
+=item *
+
+L<Cwd> extension is now (even) faster.
+
+=item *
+
+L<DB_File> extension has been updated to version 1.77.
+
+=item *
+
+L<Fcntl>, L<Socket>, and L<Sys::Syslog> have been rewritten to use the
+new-style constant dispatch section (see L<ExtUtils::Constant>).
+
+=item *
+
+L<File::Find> is now (again) reentrant. It also has been made
+more portable.
+
+=item *
+
+L<File::Glob> now supports C<GLOB_LIMIT> constant to limit the
+size of the returned list of filenames.
+
+=item *
+
+L<IO::Socket::INET> now supports C<LocalPort> of zero (usually meaning
+that the operating system will make one up.)
+
+=item *
+
+The L<vars> pragma now supports declaring fully qualified variables.
+(Something that C<our()> does not and will not support.)
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+The F<emacs/e2ctags.pl> is now much faster.
+
+=item *
+
+L<h2ph> now supports C trigraphs.
+
+=item *
+
+L<h2xs> uses the new L<ExtUtils::Constant> module which will affect
+newly created extensions that define constants. Since the new code is
+more correct (if you have two constants where the first one is a
+prefix of the second one, the first constant B<never> gets defined),
+less lossy (it uses integers for integer constant, as opposed to the
+old code that used floating point numbers even for integer constants),
+and slightly faster, you might want to consider regenerating your
+extension code (the new scheme makes regenerating easy).
+L<h2xs> now also supports C trigraphs.
+
+=item *
+
+L<libnetcfg> has been added to configure the libnet.
+
+=item *
+
+The F<Pod::Html> (and thusly L<pod2html>) now allows specifying
+a cache directory.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item *
+
+L<Locale::Maketext::TPJ13> is an article about software localization,
+originally published in The Perl Journal #13, republished here with
+kind permission.
+
+=item *
+
+More README.$PLATFORM files have been converted into pod, which also
+means that they also be installed as perl$PLATFORM documentation
+files. The new files are L<perlapollo>, L<perlbeos>, L<perldgux>,
+L<perlhurd>, L<perlmint>, L<perlnetware>, L<perlplan9>, L<perlqnx>,
+and L<perltru64>.
+
+=item *
+
+The F<Todo> and F<Todo-5.6> files have been merged into L<perltodo>.
+
+=item *
+
+Use of the F<gprof> tool to profile Perl has been documented in
+L<perlhack>. There is a make target "perl.gprof" for generating a
+gprofiled Perl executable.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 New Or Improved Platforms
+
+=over 4
+
+=item *
+
+AIX should now work better with gcc, threads, and 64-bitness. Also the
+long doubles support in AIX should be better now. See L<perlaix>.
+
+=item *
+
+AtheOS ( http://www.atheos.cx/ ) is a new platform.
+
+=item *
+
+DG/UX platform now supports the 5.005-style threads. See L<perldgux>.
+
+=item *
+
+DYNIX/ptx platform (a.k.a. dynixptx) is supported at or near osvers 4.5.2.
+
+=item *
+
+Several Mac OS (Classic) portability patches have been applied. We
+hope to get a fully working port by 5.8.0. (The remaining problems
+relate to the changed IO model of Perl.) See L<perlmacos>.
+
+=item *
+
+Mac OS X (or Darwin) should now be able to build Perl even on HFS+
+filesystems. (The case-insensitivity confused the Perl build process.)
+
+=item *
+
+NetWare from Novell is now supported. See L<perlnetware>.
+
+=item *
+
+The Amdahl UTS Unix mainframe platform is now supported.
+
+=back
+
+=head2 Generic Improvements
+
+=over 4
+
+=item *
+
+In AFS installations one can configure the root of the AFS to be
+somewhere else than the default F</afs> by using the Configure
+parameter C<-Dafsroot=/some/where/else>.
+
+=item *
+
+The version of Berkeley DB used when the Perl (and, presumably, the
+DB_File extension) was built is now available as
+C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
+from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
+DB_VERSION_PATCH_CFG> from C.
+
+=item *
+
+The Thread extension is now not built at all under ithreads
+(C<Configure -Duseithreads>) because it wouldn't work anyway (the
+Thread extension requires being Configured with C<-Duse5005threads>).
+
+=item *
+
+The C<B::Deparse> compiler backend has been so significantly improved
+that almost the whole Perl test suite passes after being deparsed. A
+make target has been added to help in further testing: C<make test.deparse>.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 5
+
+=item *
+
+The autouse pragma didn't work for Multi::Part::Function::Names.
+
+=item *
+
+The behaviour of non-decimal but numeric string constants such as
+"0x23" was platform-dependent: in some platforms that was seen as 35,
+in some as 0, in some as a floating point number (don't ask). This
+was caused by Perl using the operating system libraries in a situation
+where the result of the string to number conversion is undefined: now
+Perl consistently handles such strings as zero in numeric contexts.
+
+=item *
+
+L<dprofpp> -R didn't work.
+
+=item *
+
+PERL5OPT with embedded spaces didn't work.
+
+=item *
+
+L<Sys::Syslog> ignored the C<LOG_AUTH> constant.
+
+=back
+
+=head2 Platform Specific Changes and Fixes
+
+=over 4
+
+=item *
+
+Some versions of glibc have a broken modfl(). This affects builds
+with C<-Duselongdouble>. This version of Perl detects this brokenness
+and has a workaround for it. The glibc release 2.2.2 is known to have
+fixed the modfl() bug.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item *
+
+In the regular expression diagnostics the C<E<lt>E<lt> HERE> marker
+introduced in 5.7.0 has been changed to be C<E<lt>-- HERE> since too
+many people found the C<E<lt>E<lt>> to be too similar to here-document
+starters.
+
+=item *
+
+If you try to L<perlfunc/pack> a number less than 0 or larger than 255
+using the C<"C"> format you will get an optional warning. Similarly
+for the C<"c"> format and a number less than -128 or more than 127.
+
+=item *
+
+Certain regex modifiers such as C<(?o)> make sense only if applied to
+the entire regex. You will an optional warning if you try to do otherwise.
+
+=item *
+
+Using arrays or hashes as references (e.g. C<< %foo->{bar} >> has been
+deprecated for a while. Now you will get an optional warning.
+
+=back
+
+=head1 Source Code Enhancements
+
+=head2 MAGIC constants
+
+The MAGIC constants (e.g. C<'P'>) have been macrofied
+(e.g. C<PERL_MAGIC_TIED>) for better source code readability
+and maintainability.
+
+=head2 Better commented code
+
+F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
+
+=head2 Regex pre-/post-compilation items matched up
+
+The regex compiler now maintains a structure that identifies nodes in
+the compiled bytecode with the corresponding syntactic features of the
+original regex expression. The information is attached to the new
+C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
+complete information.
+
+=head2 gcc -Wall
+
+The C code has been made much more C<gcc -Wall> clean. Some warning
+messages still remain, though, so if you are compiling with gcc you
+will see some warnings about dubious practices. The warnings are
+being worked on.
+
+=head1 New Tests
+
+Several new tests have been added, especially for the F<lib> subsection.
+
+The tests are now reported in a different order than in earlier Perls.
+(This happens because the test scripts from under t/lib have been moved
+to be closer to the library/extension they are testing.)
+
+=head1 Known Problems
+
+Note that unlike other sections in this document (which describe
+changes since 5.7.0) this section is cumulative containing known
+problems for all the 5.7 releases.
+
+=head2 AIX
+
+=over 4
+
+=item *
+
+In AIX 4.2 Perl extensions that use C++ functions that use statics
+may have problems in that the statics are not getting initialized.
+In newer AIX releases this has been solved by linking Perl with
+the libC_r library, but unfortunately in AIX 4.2 the said library
+has an obscure bug where the various functions related to time
+(such as time() and gettimeofday()) return broken values, and
+therefore in AIX 4.2 Perl is not linked against the libC_r.
+
+=item *
+
+vac 5.0.0.0 May Produce Buggy Code For Perl
+
+The AIX C compiler vac version 5.0.0.0 may produce buggy code,
+resulting in few random tests failing, but when the failing tests
+are run by hand, they succeed. We suggest upgrading to at least
+vac version 5.0.1.0, that has been known to compile Perl correctly.
+"lslpp -L|grep vac.C" will tell you the vac version.
+
+=back
+
+=head2 Amiga Perl Invoking Mystery
+
+One cannot call Perl using the C<volume:> syntax, that is, C<perl -v>
+works, but for example C<bin:perl -v> doesn't. The exact reason is
+known but the current suspect is the F<ixemul> library.
+
+=head2 lib/ftmp-security tests warn 'system possibly insecure'
+
+Don't panic. Read INSTALL 'make test' section instead.
+
+=head2 Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
+
+The subtests 11 and 12 sometimes fail and sometimes work.
+
+=head2 HP-UX lib/io_multihomed Fails When LP64-Configured
+
+The lib/io_multihomed test may hang in HP-UX if Perl has been
+configured to be 64-bit. Because other 64-bit platforms do not hang in
+this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The
+test attempts to create and connect to "multihomed" sockets (sockets
+which have multiple IP addresses).
+
+=head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
+
+If perl is configured with -Duse64bitall, the successful result of the
+subtest 10 of lib/posix may arrive before the successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+
+=head2 Linux With Sfio Fails op/misc Test 48
+
+No known fix.
+
+=head2 OS/390
+
+OS/390 has rather many test failures but the situation is actually
+better than it was in 5.6.0, it's just that so many new modules and
+tests have been added.
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ -----------------------------------------------------------------------------
+ ../ext/B/Deparse.t 14 1 7.14% 14
+ ../ext/B/Showlex.t 1 1 100.00% 1
+ ../ext/Encode/Encode/Tcl.t 610 13 2.13% 592 594 596 598
+ 600 602 604-610
+ ../ext/IO/lib/IO/t/io_unix.t 113 28928 5 3 60.00% 3-5
+ ../ext/POSIX/POSIX.t 29 1 3.45% 14
+ ../ext/Storable/t/lock.t 255 65280 5 3 60.00% 3-5
+ ../lib/locale.t 129 33024 117 19 16.24% 99-117
+ ../lib/warnings.t 434 1 0.23% 75
+ ../lib/ExtUtils.t 27 1 3.70% 25
+ ../lib/Math/BigInt/t/bigintpm.t 1190 1 0.08% 1145
+ ../lib/Unicode/UCD.t 81 48 59.26% 1-16 49-64 66-81
+ ../lib/User/pwent.t 9 1 11.11% 4
+ op/pat.t 660 6 0.91% 242-243 424-425
+ 626-627
+ op/split.t 0 9 ?? ?? % ??
+ op/taint.t 174 3 1.72% 156 162 168
+ op/tr.t 70 3 4.29% 50 58-59
+ Failed 16/422 test scripts, 96.21% okay. 105/23251 subtests failed, 99.55% okay.
+
+=head2 op/sprintf tests 129 and 130
+
+The op/sprintf tests 129 and 130 are known to fail on some platforms.
+Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
+The failing platforms do not comply with the ANSI C Standard, line
+19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
+something other than "1" and "-1" when formatting 0.6 and -0.6 using
+the printf format "%.0f", most often they produce "0" and "-0".)
+
+=head2 Failure of Thread tests
+
+B<Note that support for 5.005-style threading remains experimental.>
+
+The following tests are known to fail due to fundamental problems in
+the 5.005 threading implementation. These are not new failures--Perl
+5.005_0x has the same bugs, but didn't have these tests.
+
+ lib/autouse.t 4
+ t/lib/thr5005.t 19-20
+
+=head2 UNICOS
+
+=over 4
+
+=item *
+
+ext/POSIX/sigaction subtests 6 and 13 may fail.
+
+=item *
+
+lib/ExtUtils may spuriously claim that subtest 28 failed,
+which is interesting since the test only has 27 tests.
+
+=item *
+
+Numerous numerical test failures
+
+ op/numconvert 209,210,217,218
+ op/override 7
+ ext/Time/HiRes/HiRes 9
+ lib/Math/BigInt/t/bigintpm 1145
+ lib/Math/Trig 25
+
+These tests fail because of yet unresolved floating point inaccuracies.
+
+=back
+
+=head2 UTS
+
+There are a few known test failures, see L<perluts>.
+
+=head2 VMS
+
+Rather many tests are failing in VMS but that actually more tests
+succeed in VMS than they used to, it's just that there are many,
+many more tests than there used to be.
+
+Here are the known failures from some compiler/platform combinations.
+
+DEC C V5.3-006 on OpenVMS VAX V6.2
+
+ [-.ext.list.util.t]tainted..............FAILED on test 3
+ [-.ext.posix]sigaction..................FAILED on test 7
+ [-.ext.time.hires]hires.................FAILED on test 14
+ [-.lib.file.find]taint..................FAILED on test 17
+ [-.lib.math.bigint.t]bigintpm...........FAILED on test 1183
+ [-.lib.test.simple.t]exit...............FAILED on test 1
+ [.lib]vmsish............................FAILED on test 13
+ [.op]sprintf............................FAILED on test 12
+ Failed 8/399 tests, 91.23% okay.
+
+DEC C V6.0-001 on OpenVMS Alpha V7.2-1 and
+Compaq C V6.2-008 on OpenVMS Alpha V7.1
+
+ [-.ext.list.util.t]tainted..............FAILED on test 3
+ [-.lib.file.find]taint..................FAILED on test 17
+ [-.lib.test.simple.t]exit...............FAILED on test 1
+ [.lib]vmsish............................FAILED on test 13
+ Failed 4/399 tests, 92.48% okay.
+
+Compaq C V6.4-005 on OpenVMS Alpha 7.2.1
+
+ [-.ext.b]showlex........................FAILED on test 1
+ [-.ext.list.util.t]tainted..............FAILED on test 3
+ [-.lib.file.find]taint..................FAILED on test 17
+ [-.lib.test.simple.t]exit...............FAILED on test 1
+ [.lib]vmsish............................FAILED on test 13
+ [.op]misc...............................FAILED on test 49
+ Failed 6/401 tests, 92.77% okay.
+
+=head2 Win32
+
+In multi-CPU boxes there are some problems with the I/O buffering:
+some output may appear twice.
+
+=head2 Localising a Tied Variable Leaks Memory
+
+ use Tie::Hash;
+ tie my %tie_hash => 'Tie::StdHash';
+
+ ...
+
+ local($tie_hash{Foo}) = 1; # leaks
+
+Code like the above is known to leak memory every time the local()
+is executed.
+
+=head2 Self-tying of Arrays and Hashes Is Forbidden
+
+Self-tying of arrays and hashes is broken in rather deep and
+hard-to-fix ways. As a stop-gap measure to avoid people from getting
+frustrated at the mysterious results (core dumps, most often) it is
+for now forbidden (you will get a fatal error even from an attempt).
+
+=head2 Variable Attributes are not Currently Usable for Tieing
+
+This limitation will hopefully be fixed in future. (Subroutine
+attributes work fine for tieing, see L<Attribute::Handlers>).
+
+=head2 Building Extensions Can Fail Because Of Largefiles
+
+Some extensions like mod_perl are known to have issues with
+`largefiles', a change brought by Perl 5.6.0 in which file offsets
+default to 64 bits wide, where supported. Modules may fail to compile
+at all or compile and work incorrectly. Currently there is no good
+solution for the problem, but Configure now provides appropriate
+non-largefile ccflags, ldflags, libswanted, and libs in the %Config
+hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are
+having problems can try configuring themselves without the
+largefileness. This is admittedly not a clean solution, and the
+solution may not even work at all. One potential failure is whether
+one can (or, if one can, whether it's a good idea) link together at
+all binaries with different ideas about file offsets, all this is
+platform-dependent.
+
+=head2 The Compiler Suite Is Still Experimental
+
+The compiler suite is slowly getting better but is nowhere near
+working order yet.
+
+=head2 The Long Double Support is Still Experimental
+
+The ability to configure Perl's numbers to use "long doubles",
+floating point numbers of hopefully better accuracy, is still
+experimental. The implementations of long doubles are not yet
+widespread and the existing implementations are not quite mature
+or standardised, therefore trying to support them is a rare
+and moving target. The gain of more precision may also be offset
+by slowdown in computations (more bits to move around, and the
+operations are more likely to be executed by less optimised
+libraries).
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ There may also be
+information at http://www.perl.com/perl/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
+from The Perl Porters and Perl Users submitting feedback and patches.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl573delta.pod b/Master/tlpkg/tlperl/lib/pods/perl573delta.pod
new file mode 100644
index 00000000000..00e73fed8bf
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl573delta.pod
@@ -0,0 +1,246 @@
+=head1 NAME
+
+perl573delta - what's new for perl v5.7.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.7.2 release and the
+5.7.3 release.
+
+(To view the differences between the 5.6.0 release and the 5.7.0
+release, see L<perl570delta>. To view the differences between the
+5.7.0 release and the 5.7.1 release, see L<perl571delta>. To view
+the differences between the 5.7.1 release and the 5.7.2 release,
+see L<perl572delta>.)
+
+=head1 Changes
+
+This is just a selected list of some of the more notable changes.
+The numbers refer to the Perl repository change numbers; see
+L<Changes58> (or L<Changes> in Perl 5.8.1). In addition to these
+changes, lots of work took place in integrating threads, PerlIO, and
+Unicode; general code cleanup; and last but not least porting to
+non-Unix lands such as Win32, VMS, Cygwin, DJGPP, VOS, MacOS Classic,
+and EBCDIC.
+
+=over 4
+
+=item 11362
+
+add LC_MESSAGES to POSIX :locale_h export tag
+
+=item 11371
+
+add DEL to [:cntrl:]
+
+=item 11375
+
+make h2ph understand constants like 1234L and 5678LL
+
+=item 11405
+
+Win32: fix bugs in handling of the virtualized environment
+
+=item 11410
+
+fix a bug in the security taint checking of open()
+
+=item 11423
+
+make perl fork() safe even on platforms that don't have pthread_atfork()
+
+=item 11459
+
+make switching optimization and debugging levels during Perl builds
+easier via the OPTIMIZE environment variable
+
+=item 11475
+
+make split()'s unused captures to be undef, not ''
+
+=item 11485
+
+Search::Dict: allow transforming lines before comparing
+
+=item 11490
+
+allow installing extra modules or bundles when building Perl
+
+=item 11516
+
+add -Wall in cflags when compiling with gcc to weed out dubious
+C practices
+
+=item 11541
+
+pluggable optimizer
+
+=item 11549
+
+WinCE: integrate the port
+
+=item 11589
+
+Win32: 4-arg select was broken
+
+=item 11594
+
+introduce the perlivp utility for verifying the Perl installation
+(IVP = Installation Verification Procedure)
+
+=item 11623
+
+rename lib/unicode to lib/unicore to avoid case-insensitivity problems
+with lib/Unicode
+
+=item 111631
+
+remove Time::Piece
+
+=item 11643
+
+document that use utf8 is not the right way most of the time
+
+=item 11656
+
+allow building perl with -DUSE_UTF8_SCRIPTS which makes UTF-8
+the default script encoding (not the default since that would
+break all scripts having legacy eight-bit data in them)
+
+=item 11725
+
+division preserving 64-bit integers
+
+=item 11743
+
+document the coderef-in-@INC feature
+
+=item 11794
+
+modulo (%) preserving 64-bit integers
+
+=item 11825
+
+update to Unicode 3.1.1
+
+=item 11865
+
+add the \[$@%&*] prototype support
+
+=item 11874
+
+oct() and hex() in glorious 64 bit
+
+=item 11877
+
+Class::Struct: allow recursive classes
+
+=item 11993
+
+fix unpack U to be the reverse of pack U
+
+=item 12056
+
+VMS: waitpid enhancements
+
+=item 12180
+
+unpack("Z*Z*", pack("Z*Z*", ..)) was broken
+
+=item 12243
+
+Devel::Peek: display UTF-8 SVs also as \x{...}
+
+=item 12288
+
+Data::Dumper: option to sort hashes
+
+=item 12542
+
+add perlpodspec
+
+=item 12652
+
+threadsafe DynaLoader, re, Opcode, File::Glob, and B
+
+=item 12756
+
+support BeOS better
+
+=item 12874
+
+read-only hashes (user-level interface is Hash::Util)
+
+=item 13162
+
+add Devel::PPPort
+
+=item 13179
+
+add the sort pragma
+
+=item 13326
+
+VMS: fix perl -P
+
+=item 13358
+
+add perlpacktut
+
+=item 13452
+
+SUPER-UX: add hints file
+
+=item 13575
+
+Win32: non-blocking waitpid(-1,WNOHANG)
+
+=item 13684
+
+introduce the -t option for gentler taint checking
+
+=item 14694
+
+add the if pragma
+
+=item 14832
+
+implement IV/UV/NV/long double un/packing with j/J/F/D
+
+=item 14854
+
+document the new taint behaviour of exec LIST and system LIST
+
+=back
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.com/, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
+from The Perl Porters and Perl Users submitting feedback and patches.
+
+Send omissions or corrections to <F<perlbug@perl.org>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl581delta.pod b/Master/tlpkg/tlperl/lib/pods/perl581delta.pod
new file mode 100644
index 00000000000..cd88c73ba62
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl581delta.pod
@@ -0,0 +1,1102 @@
+=head1 NAME
+
+perl581delta - what is new for perl v5.8.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.0 release and
+the 5.8.1 release.
+
+If you are upgrading from an earlier release such as 5.6.1, first read
+the L<perl58delta>, which describes differences between 5.6.0 and
+5.8.0.
+
+In case you are wondering about 5.6.1, it was bug-fix-wise rather
+identical to the development release 5.7.1. Confused? This timeline
+hopefully helps a bit: it lists the new major releases, their maintenance
+releases, and the development releases.
+
+ New Maintenance Development
+
+ 5.6.0 2000-Mar-22
+ 5.7.0 2000-Sep-02
+ 5.6.1 2001-Apr-08
+ 5.7.1 2001-Apr-09
+ 5.7.2 2001-Jul-13
+ 5.7.3 2002-Mar-05
+ 5.8.0 2002-Jul-18
+ 5.8.1 2003-Sep-25
+
+=head1 Incompatible Changes
+
+=head2 Hash Randomisation
+
+Mainly due to security reasons, the "random ordering" of hashes
+has been made even more random. Previously while the order of hash
+elements from keys(), values(), and each() was essentially random,
+it was still repeatable. Now, however, the order varies between
+different runs of Perl.
+
+B<Perl has never guaranteed any ordering of the hash keys>, and the
+ordering has already changed several times during the lifetime of
+Perl 5. Also, the ordering of hash keys has always been, and
+continues to be, affected by the insertion order.
+
+The added randomness may affect applications.
+
+One possible scenario is when output of an application has included
+hash data. For example, if you have used the Data::Dumper module to
+dump data into different files, and then compared the files to see
+whether the data has changed, now you will have false positives since
+the order in which hashes are dumped will vary. In general the cure
+is to sort the keys (or the values); in particular for Data::Dumper to
+use the C<Sortkeys> option. If some particular order is really
+important, use tied hashes: for example the Tie::IxHash module
+which by default preserves the order in which the hash elements
+were added.
+
+More subtle problem is reliance on the order of "global destruction".
+That is what happens at the end of execution: Perl destroys all data
+structures, including user data. If your destructors (the DESTROY
+subroutines) have assumed any particular ordering to the global
+destruction, there might be problems ahead. For example, in a
+destructor of one object you cannot assume that objects of any other
+class are still available, unless you hold a reference to them.
+If the environment variable PERL_DESTRUCT_LEVEL is set to a non-zero
+value, or if Perl is exiting a spawned thread, it will also destruct
+the ordinary references and the symbol tables that are no longer in use.
+You can't call a class method or an ordinary function on a class that
+has been collected that way.
+
+The hash randomisation is certain to reveal hidden assumptions about
+some particular ordering of hash elements, and outright bugs: it
+revealed a few bugs in the Perl core and core modules.
+
+To disable the hash randomisation in runtime, set the environment
+variable PERL_HASH_SEED to 0 (zero) before running Perl (for more
+information see L<perlrun/PERL_HASH_SEED>), or to disable the feature
+completely in compile time, compile with C<-DNO_HASH_SEED> (see F<INSTALL>).
+
+See L<perlsec/"Algorithmic Complexity Attacks"> for the original
+rationale behind this change.
+
+=head2 UTF-8 On Filehandles No Longer Activated By Locale
+
+In Perl 5.8.0 all filehandles, including the standard filehandles,
+were implicitly set to be in Unicode UTF-8 if the locale settings
+indicated the use of UTF-8. This feature caused too many problems,
+so the feature was turned off and redesigned: see L</"Core Enhancements">.
+
+=head2 Single-number v-strings are no longer v-strings before "=>"
+
+The version strings or v-strings (see L<perldata/"Version Strings">)
+feature introduced in Perl 5.6.0 has been a source of some confusion--
+especially when the user did not want to use it, but Perl thought it
+knew better. Especially troublesome has been the feature that before
+a "=>" a version string (a "v" followed by digits) has been interpreted
+as a v-string instead of a string literal. In other words:
+
+ %h = ( v65 => 42 );
+
+has meant since Perl 5.6.0
+
+ %h = ( 'A' => 42 );
+
+(at least in platforms of ASCII progeny) Perl 5.8.1 restores the
+more natural interpretation
+
+ %h = ( 'v65' => 42 );
+
+The multi-number v-strings like v65.66 and 65.66.67 still continue to
+be v-strings in Perl 5.8.
+
+=head2 (Win32) The -C Switch Has Been Repurposed
+
+The -C switch has changed in an incompatible way. The old semantics
+of this switch only made sense in Win32 and only in the "use utf8"
+universe in 5.6.x releases, and do not make sense for the Unicode
+implementation in 5.8.0. Since this switch could not have been used
+by anyone, it has been repurposed. The behavior that this switch
+enabled in 5.6.x releases may be supported in a transparent,
+data-dependent fashion in a future release.
+
+For the new life of this switch, see L<"UTF-8 no longer default under
+UTF-8 locales">, and L<perlrun/-C>.
+
+=head2 (Win32) The /d Switch Of cmd.exe
+
+Perl 5.8.1 uses the /d switch when running the cmd.exe shell
+internally for system(), backticks, and when opening pipes to external
+programs. The extra switch disables the execution of AutoRun commands
+from the registry, which is generally considered undesirable when
+running external programs. If you wish to retain compatibility with
+the older behavior, set PERL5SHELL in your environment to C<cmd /x/c>.
+
+=head1 Core Enhancements
+
+=head2 UTF-8 no longer default under UTF-8 locales
+
+In Perl 5.8.0 many Unicode features were introduced. One of them
+was found to be of more nuisance than benefit: the automagic
+(and silent) "UTF-8-ification" of filehandles, including the
+standard filehandles, if the user's locale settings indicated
+use of UTF-8.
+
+For example, if you had C<en_US.UTF-8> as your locale, your STDIN and
+STDOUT were automatically "UTF-8", in other words an implicit
+binmode(..., ":utf8") was made. This meant that trying to print, say,
+chr(0xff), ended up printing the bytes 0xc3 0xbf. Hardly what
+you had in mind unless you were aware of this feature of Perl 5.8.0.
+The problem is that the vast majority of people weren't: for example
+in RedHat releases 8 and 9 the B<default> locale setting is UTF-8, so
+all RedHat users got UTF-8 filehandles, whether they wanted it or not.
+The pain was intensified by the Unicode implementation of Perl 5.8.0
+(still) having nasty bugs, especially related to the use of s/// and
+tr///. (Bugs that have been fixed in 5.8.1)
+
+Therefore a decision was made to backtrack the feature and change it
+from implicit silent default to explicit conscious option. The new
+Perl command line option C<-C> and its counterpart environment
+variable PERL_UNICODE can now be used to control how Perl and Unicode
+interact at interfaces like I/O and for example the command line
+arguments. See L<perlrun/-C> and L<perlrun/PERL_UNICODE> for more
+information.
+
+=head2 Unsafe signals again available
+
+In Perl 5.8.0 the so-called "safe signals" were introduced. This
+means that Perl no longer handles signals immediately but instead
+"between opcodes", when it is safe to do so. The earlier immediate
+handling easily could corrupt the internal state of Perl, resulting
+in mysterious crashes.
+
+However, the new safer model has its problems too. Because now an
+opcode, a basic unit of Perl execution, is never interrupted but
+instead let to run to completion, certain operations that can take a
+long time now really do take a long time. For example, certain
+network operations have their own blocking and timeout mechanisms, and
+being able to interrupt them immediately would be nice.
+
+Therefore perl 5.8.1 introduces a "backdoor" to restore the pre-5.8.0
+(pre-5.7.3, really) signal behaviour. Just set the environment variable
+PERL_SIGNALS to C<unsafe>, and the old immediate (and unsafe)
+signal handling behaviour returns. See L<perlrun/PERL_SIGNALS>
+and L<perlipc/"Deferred Signals (Safe Signals)">.
+
+In completely unrelated news, you can now use safe signals with
+POSIX::SigAction. See L<POSIX/POSIX::SigAction>.
+
+=head2 Tied Arrays with Negative Array Indices
+
+Formerly, the indices passed to C<FETCH>, C<STORE>, C<EXISTS>, and
+C<DELETE> methods in tied array class were always non-negative. If
+the actual argument was negative, Perl would call FETCHSIZE implicitly
+and add the result to the index before passing the result to the tied
+array method. This behaviour is now optional. If the tied array class
+contains a package variable named C<$NEGATIVE_INDICES> which is set to
+a true value, negative values will be passed to C<FETCH>, C<STORE>,
+C<EXISTS>, and C<DELETE> unchanged.
+
+=head2 local ${$x}
+
+The syntaxes
+
+ local ${$x}
+ local @{$x}
+ local %{$x}
+
+now do localise variables, given that the $x is a valid variable name.
+
+=head2 Unicode Character Database 4.0.0
+
+The copy of the Unicode Character Database included in Perl 5.8 has
+been updated to 4.0.0 from 3.2.0. This means for example that the
+Unicode character properties are as in Unicode 4.0.0.
+
+=head2 Deprecation Warnings
+
+There is one new feature deprecation. Perl 5.8.0 forgot to add
+some deprecation warnings, these warnings have now been added.
+Finally, a reminder of an impending feature removal.
+
+=head3 (Reminder) Pseudo-hashes are deprecated (really)
+
+Pseudo-hashes were deprecated in Perl 5.8.0 and will be removed in
+Perl 5.10.0, see L<perl58delta> for details. Each attempt to access
+pseudo-hashes will trigger the warning C<Pseudo-hashes are deprecated>.
+If you really want to continue using pseudo-hashes but not to see the
+deprecation warnings, use:
+
+ no warnings 'deprecated';
+
+Or you can continue to use the L<fields> pragma, but please don't
+expect the data structures to be pseudohashes any more.
+
+=head3 (Reminder) 5.005-style threads are deprecated (really)
+
+5.005-style threads (activated by C<use Thread;>) were deprecated in
+Perl 5.8.0 and will be removed after Perl 5.8, see L<perl58delta> for
+details. Each 5.005-style thread creation will trigger the warning
+C<5.005 threads are deprecated>. If you really want to continue
+using the 5.005 threads but not to see the deprecation warnings, use:
+
+ no warnings 'deprecated';
+
+=head3 (Reminder) The $* variable is deprecated (really)
+
+The C<$*> variable controlling multi-line matching has been deprecated
+and will be removed after 5.8. The variable has been deprecated for a
+long time, and a deprecation warning C<Use of $* is deprecated> is given,
+now the variable will just finally be removed. The functionality has
+been supplanted by the C</s> and C</m> modifiers on pattern matching.
+If you really want to continue using the C<$*>-variable but not to see
+the deprecation warnings, use:
+
+ no warnings 'deprecated';
+
+=head2 Miscellaneous Enhancements
+
+C<map> in void context is no longer expensive. C<map> is now context
+aware, and will not construct a list if called in void context.
+
+If a socket gets closed by the server while printing to it, the client
+now gets a SIGPIPE. While this new feature was not planned, it fell
+naturally out of PerlIO changes, and is to be considered an accidental
+feature.
+
+PerlIO::get_layers(FH) returns the names of the PerlIO layers
+active on a filehandle.
+
+PerlIO::via layers can now have an optional UTF8 method to
+indicate whether the layer wants to "auto-:utf8" the stream.
+
+utf8::is_utf8() has been added as a quick way to test whether
+a scalar is encoded internally in UTF-8 (Unicode).
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules And Pragmata
+
+The following modules and pragmata have been updated since Perl 5.8.0:
+
+=over 4
+
+=item base
+
+=item B::Bytecode
+
+In much better shape than it used to be. Still far from perfect, but
+maybe worth a try.
+
+=item B::Concise
+
+=item B::Deparse
+
+=item Benchmark
+
+An optional feature, C<:hireswallclock>, now allows for high
+resolution wall clock times (uses Time::HiRes).
+
+=item ByteLoader
+
+See B::Bytecode.
+
+=item bytes
+
+Now has bytes::substr.
+
+=item CGI
+
+=item charnames
+
+One can now have custom character name aliases.
+
+=item CPAN
+
+There is now a simple command line frontend to the CPAN.pm
+module called F<cpan>.
+
+=item Data::Dumper
+
+A new option, Pair, allows choosing the separator between hash keys
+and values.
+
+=item DB_File
+
+=item Devel::PPPort
+
+=item Digest::MD5
+
+=item Encode
+
+Significant updates on the encoding pragma functionality
+(tr/// and the DATA filehandle, formats).
+
+If a filehandle has been marked as to have an encoding, unmappable
+characters are detected already during input, not later (when the
+corrupted data is being used).
+
+The ISO 8859-6 conversion table has been corrected (the 0x30..0x39
+erroneously mapped to U+0660..U+0669, instead of U+0030..U+0039). The
+GSM 03.38 conversion did not handle escape sequences correctly. The
+UTF-7 encoding has been added (making Encode feature-complete with
+Unicode::String).
+
+=item fields
+
+=item libnet
+
+=item Math::BigInt
+
+A lot of bugs have been fixed since v1.60, the version included in Perl
+v5.8.0. Especially noteworthy are the bug in Calc that caused div and mod to
+fail for some large values, and the fixes to the handling of bad inputs.
+
+Some new features were added, e.g. the broot() method, you can now pass
+parameters to config() to change some settings at runtime, and it is now
+possible to trap the creation of NaN and infinity.
+
+As usual, some optimizations took place and made the math overall a tad
+faster. In some cases, quite a lot faster, actually. Especially alternative
+libraries like Math::BigInt::GMP benefit from this. In addition, a lot of the
+quite clunky routines like fsqrt() and flog() are now much much faster.
+
+=item MIME::Base64
+
+=item NEXT
+
+Diamond inheritance now works.
+
+=item Net::Ping
+
+=item PerlIO::scalar
+
+Reading from non-string scalars (like the special variables, see
+L<perlvar>) now works.
+
+=item podlators
+
+=item Pod::LaTeX
+
+=item PodParsers
+
+=item Pod::Perldoc
+
+Complete rewrite. As a side-effect, no longer refuses to startup when
+run by root.
+
+=item Scalar::Util
+
+New utilities: refaddr, isvstring, looks_like_number, set_prototype.
+
+=item Storable
+
+Can now store code references (via B::Deparse, so not foolproof).
+
+=item strict
+
+Earlier versions of the strict pragma did not check the parameters
+implicitly passed to its "import" (use) and "unimport" (no) routine.
+This caused the false idiom such as:
+
+ use strict qw(@ISA);
+ @ISA = qw(Foo);
+
+This however (probably) raised the false expectation that the strict
+refs, vars and subs were being enforced (and that @ISA was somehow
+"declared"). But the strict refs, vars, and subs are B<not> enforced
+when using this false idiom.
+
+Starting from Perl 5.8.1, the above B<will> cause an error to be
+raised. This may cause programs which used to execute seemingly
+correctly without warnings and errors to fail when run under 5.8.1.
+This happens because
+
+ use strict qw(@ISA);
+
+will now fail with the error:
+
+ Unknown 'strict' tag(s) '@ISA'
+
+The remedy to this problem is to replace this code with the correct idiom:
+
+ use strict;
+ use vars qw(@ISA);
+ @ISA = qw(Foo);
+
+=item Term::ANSIcolor
+
+=item Test::Harness
+
+Now much more picky about extra or missing output from test scripts.
+
+=item Test::More
+
+=item Test::Simple
+
+=item Text::Balanced
+
+=item Time::HiRes
+
+Use of nanosleep(), if available, allows mixing subsecond sleeps with
+alarms.
+
+=item threads
+
+Several fixes, for example for join() problems and memory
+leaks. In some platforms (like Linux) that use glibc the minimum memory
+footprint of one ithread has been reduced by several hundred kilobytes.
+
+=item threads::shared
+
+Many memory leaks have been fixed.
+
+=item Unicode::Collate
+
+=item Unicode::Normalize
+
+=item Win32::GetFolderPath
+
+=item Win32::GetOSVersion
+
+Now returns extra information.
+
+=back
+
+=head1 Utility Changes
+
+The C<h2xs> utility now produces a more modern layout:
+F<Foo-Bar/lib/Foo/Bar.pm> instead of F<Foo/Bar/Bar.pm>.
+Also, the boilerplate test is now called F<t/Foo-Bar.t>
+instead of F<t/1.t>.
+
+The Perl debugger (F<lib/perl5db.pl>) has now been extensively
+documented and bugs found while documenting have been fixed.
+
+C<perldoc> has been rewritten from scratch to be more robust and
+feature rich.
+
+C<perlcc -B> works now at least somewhat better, while C<perlcc -c>
+is rather more broken. (The Perl compiler suite as a whole continues
+to be experimental.)
+
+=head1 New Documentation
+
+perl573delta has been added to list the differences between the
+(now quite obsolete) development releases 5.7.2 and 5.7.3.
+
+perl58delta has been added: it is the perldelta of 5.8.0, detailing
+the differences between 5.6.0 and 5.8.0.
+
+perlartistic has been added: it is the Artistic License in pod format,
+making it easier for modules to refer to it.
+
+perlcheat has been added: it is a Perl cheat sheet.
+
+perlgpl has been added: it is the GNU General Public License in pod
+format, making it easier for modules to refer to it.
+
+perlmacosx has been added to tell about the installation and use
+of Perl in Mac OS X.
+
+perlos400 has been added to tell about the installation and use
+of Perl in OS/400 PASE.
+
+perlreref has been added: it is a regular expressions quick reference.
+
+=head1 Installation and Configuration Improvements
+
+The Unix standard Perl location, F</usr/bin/perl>, is no longer
+overwritten by default if it exists. This change was very prudent
+because so many Unix vendors already provide a F</usr/bin/perl>,
+but simultaneously many system utilities may depend on that
+exact version of Perl, so better not to overwrite it.
+
+One can now specify installation directories for site and vendor man
+and HTML pages, and site and vendor scripts. See F<INSTALL>.
+
+One can now specify a destination directory for Perl installation
+by specifying the DESTDIR variable for C<make install>. (This feature
+is slightly different from the previous C<Configure -Dinstallprefix=...>.)
+See F<INSTALL>.
+
+gcc versions 3.x introduced a new warning that caused a lot of noise
+during Perl compilation: C<gcc -Ialreadyknowndirectory (warning:
+changing search order)>. This warning has now been avoided by
+Configure weeding out such directories before the compilation.
+
+One can now build subsets of Perl core modules by using the
+Configure flags C<-Dnoextensions=...> and C<-Donlyextensions=...>,
+see F<INSTALL>.
+
+=head2 Platform-specific enhancements
+
+In Cygwin Perl can now be built with threads (C<Configure -Duseithreads>).
+This works with both Cygwin 1.3.22 and Cygwin 1.5.3.
+
+In newer FreeBSD releases Perl 5.8.0 compilation failed because of
+trying to use F<malloc.h>, which in FreeBSD is just a dummy file, and
+a fatal error to even try to use. Now F<malloc.h> is not used.
+
+Perl is now known to build also in Hitachi HI-UXMPP.
+
+Perl is now known to build again in LynxOS.
+
+Mac OS X now installs with Perl version number embedded in
+installation directory names for easier upgrading of user-compiled
+Perl, and the installation directories in general are more standard.
+In other words, the default installation no longer breaks the
+Apple-provided Perl. On the other hand, with C<Configure -Dprefix=/usr>
+you can now really replace the Apple-supplied Perl (B<please be careful>).
+
+Mac OS X now builds Perl statically by default. This change was done
+mainly for faster startup times. The Apple-provided Perl is still
+dynamically linked and shared, and you can enable the sharedness for
+your own Perl builds by C<Configure -Duseshrplib>.
+
+Perl has been ported to IBM's OS/400 PASE environment. The best way
+to build a Perl for PASE is to use an AIX host as a cross-compilation
+environment. See README.os400.
+
+Yet another cross-compilation option has been added: now Perl builds
+on OpenZaurus, an Linux distribution based on Mandrake + Embedix for
+the Sharp Zaurus PDA. See the Cross/README file.
+
+Tru64 when using gcc 3 drops the optimisation for F<toke.c> to C<-O2>
+because of gigantic memory use with the default C<-O3>.
+
+Tru64 can now build Perl with the newer Berkeley DBs.
+
+Building Perl on WinCE has been much enhanced, see F<README.ce>
+and F<README.perlce>.
+
+=head1 Selected Bug Fixes
+
+=head2 Closures, eval and lexicals
+
+There have been many fixes in the area of anonymous subs, lexicals and
+closures. Although this means that Perl is now more "correct", it is
+possible that some existing code will break that happens to rely on
+the faulty behaviour. In practice this is unlikely unless your code
+contains a very complex nesting of anonymous subs, evals and lexicals.
+
+=head2 Generic fixes
+
+If an input filehandle is marked C<:utf8> and Perl sees illegal UTF-8
+coming in when doing C<< <FH> >>, if warnings are enabled a warning is
+immediately given - instead of being silent about it and Perl being
+unhappy about the broken data later. (The C<:encoding(utf8)> layer
+also works the same way.)
+
+binmode(SOCKET, ":utf8") only worked on the input side, not on the
+output side of the socket. Now it works both ways.
+
+For threaded Perls certain system database functions like getpwent()
+and getgrent() now grow their result buffer dynamically, instead of
+failing. This means that at sites with lots of users and groups the
+functions no longer fail by returning only partial results.
+
+Perl 5.8.0 had accidentally broken the capability for users
+to define their own uppercase<->lowercase Unicode mappings
+(as advertised by the Camel). This feature has been fixed and
+is also documented better.
+
+In 5.8.0 this
+
+ $some_unicode .= <FH>;
+
+didn't work correctly but instead corrupted the data. This has now
+been fixed.
+
+Tied methods like FETCH etc. may now safely access tied values, i.e.
+resulting in a recursive call to FETCH etc. Remember to break the
+recursion, though.
+
+At startup Perl blocks the SIGFPE signal away since there isn't much
+Perl can do about it. Previously this blocking was in effect also for
+programs executed from within Perl. Now Perl restores the original
+SIGFPE handling routine, whatever it was, before running external
+programs.
+
+Linenumbers in Perl scripts may now be greater than 65536, or 2**16.
+(Perl scripts have always been able to be larger than that, it's just
+that the linenumber for reported errors and warnings have "wrapped
+around".) While scripts that large usually indicate a need to rethink
+your code a bit, such Perl scripts do exist, for example as results
+from generated code. Now linenumbers can go all the way to
+4294967296, or 2**32.
+
+=head2 Platform-specific fixes
+
+Linux
+
+=over 4
+
+=item *
+
+Setting $0 works again (with certain limitations that
+Perl cannot do much about: see L<perlvar/$0>)
+
+=back
+
+HP-UX
+
+=over 4
+
+=item *
+
+Setting $0 now works.
+
+=back
+
+VMS
+
+=over 4
+
+=item *
+
+Configuration now tests for the presence of C<poll()>, and IO::Poll
+now uses the vendor-supplied function if detected.
+
+=item *
+
+A rare access violation at Perl start-up could occur if the Perl image was
+installed with privileges or if there was an identifier with the
+subsystem attribute set in the process's rightslist. Either of these
+circumstances triggered tainting code that contained a pointer bug.
+The faulty pointer arithmetic has been fixed.
+
+=item *
+
+The length limit on values (not keys) in the %ENV hash has been raised
+from 255 bytes to 32640 bytes (except when the PERL_ENV_TABLES setting
+overrides the default use of logical names for %ENV). If it is
+necessary to access these long values from outside Perl, be aware that
+they are implemented using search list logical names that store the
+value in pieces, each 255-byte piece (up to 128 of them) being an
+element in the search list. When doing a lookup in %ENV from within
+Perl, the elements are combined into a single value. The existing
+VMS-specific ability to access individual elements of a search list
+logical name via the $ENV{'foo;N'} syntax (where N is the search list
+index) is unimpaired.
+
+=item *
+
+The piping implementation now uses local rather than global DCL
+symbols for inter-process communication.
+
+=item *
+
+File::Find could become confused when navigating to a relative
+directory whose name collided with a logical name. This problem has
+been corrected by adding directory syntax to relative path names, thus
+preventing logical name translation.
+
+=back
+
+Win32
+
+=over 4
+
+=item *
+
+A memory leak in the fork() emulation has been fixed.
+
+=item *
+
+The return value of the ioctl() built-in function was accidentally
+broken in 5.8.0. This has been corrected.
+
+=item *
+
+The internal message loop executed by perl during blocking operations
+sometimes interfered with messages that were external to Perl.
+This often resulted in blocking operations terminating prematurely or
+returning incorrect results, when Perl was executing under environments
+that could generate Windows messages. This has been corrected.
+
+=item *
+
+Pipes and sockets are now automatically in binary mode.
+
+=item *
+
+The four-argument form of select() did not preserve $! (errno) properly
+when there were errors in the underlying call. This is now fixed.
+
+=item *
+
+The "CR CR LF" problem of has been fixed, binmode(FH, ":crlf")
+is now effectively a no-op.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+All the warnings related to pack() and unpack() were made more
+informative and consistent.
+
+=head2 Changed "A thread exited while %d threads were running"
+
+The old version
+
+ A thread exited while %d other threads were still running
+
+was misleading because the "other" included also the thread giving
+the warning.
+
+=head2 Removed "Attempt to clear a restricted hash"
+
+It is not illegal to clear a restricted hash, so the warning
+was removed.
+
+=head2 New "Illegal declaration of anonymous subroutine"
+
+You must specify the block of code for C<sub>.
+
+=head2 Changed "Invalid range "%s" in transliteration operator"
+
+The old version
+
+ Invalid [] range "%s" in transliteration operator
+
+was simply wrong because there are no "[] ranges" in tr///.
+
+=head2 New "Missing control char name in \c"
+
+Self-explanatory.
+
+=head2 New "Newline in left-justified string for %s"
+
+The padding spaces would appear after the newline, which is
+probably not what you had in mind.
+
+=head2 New "Possible precedence problem on bitwise %c operator"
+
+If you think this
+
+ $x & $y == 0
+
+tests whether the bitwise AND of $x and $y is zero,
+you will like this warning.
+
+=head2 New "Pseudo-hashes are deprecated"
+
+This warning should have been already in 5.8.0, since they are.
+
+=head2 New "read() on %s filehandle %s"
+
+You cannot read() (or sysread()) from a closed or unopened filehandle.
+
+=head2 New "5.005 threads are deprecated"
+
+This warning should have been already in 5.8.0, since they are.
+
+=head2 New "Tied variable freed while still in use"
+
+Something pulled the plug on a live tied variable, Perl plays
+safe by bailing out.
+
+=head2 New "To%s: illegal mapping '%s'"
+
+An illegal user-defined Unicode casemapping was specified.
+
+=head2 New "Use of freed value in iteration"
+
+Something modified the values being iterated over. This is not good.
+
+=head1 Changed Internals
+
+These news matter to you only if you either write XS code or like to
+know about or hack Perl internals (using Devel::Peek or any of the
+C<B::> modules counts), or like to run Perl with the C<-D> option.
+
+The embedding examples of L<perlembed> have been reviewed to be
+up to date and consistent: for example, the correct use of
+PERL_SYS_INIT3() and PERL_SYS_TERM().
+
+Extensive reworking of the pad code (the code responsible
+for lexical variables) has been conducted by Dave Mitchell.
+
+Extensive work on the v-strings by John Peacock.
+
+UTF-8 length and position cache: to speed up the handling of Unicode
+(UTF-8) scalars, a cache was introduced. Potential problems exist if
+an extension bypasses the official APIs and directly modifies the PV
+of an SV: the UTF-8 cache does not get cleared as it should.
+
+APIs obsoleted in Perl 5.8.0, like sv_2pv, sv_catpvn, sv_catsv,
+sv_setsv, are again available.
+
+Certain Perl core C APIs like cxinc and regatom are no longer
+available at all to code outside the Perl core of the Perl core
+extensions. This is intentional. They never should have been
+available with the shorter names, and if you application depends on
+them, you should (be ashamed and) contact perl5-porters to discuss
+what are the proper APIs.
+
+Certain Perl core C APIs like C<Perl_list> are no longer available
+without their C<Perl_> prefix. If your XS module stops working
+because some functions cannot be found, in many cases a simple fix is
+to add the C<Perl_> prefix to the function and the thread context
+C<aTHX_> as the first argument of the function call. This is also how
+it should always have been done: letting the Perl_-less forms to leak
+from the core was an accident. For cleaner embedding you can also
+force this for all APIs by defining at compile time the cpp define
+PERL_NO_SHORT_NAMES.
+
+Perl_save_bool() has been added.
+
+Regexp objects (those created with C<qr>) now have S-magic rather than
+R-magic. This fixed regexps of the form /...(??{...;$x})/ to no
+longer ignore changes made to $x. The S-magic avoids dropping
+the caching optimization and making (??{...}) constructs obscenely
+slow (and consequently useless). See also L<perlguts/"Magic Variables">.
+Regexp::Copy was affected by this change.
+
+The Perl internal debugging macros DEBUG() and DEB() have been renamed
+to PERL_DEBUG() and PERL_DEB() to avoid namespace conflicts.
+
+C<-DL> removed (the leaktest had been broken and unsupported for years,
+use alternative debugging mallocs or tools like valgrind and Purify).
+
+Verbose modifier C<v> added for C<-DXv> and C<-Dsv>, see L<perlrun>.
+
+=head1 New Tests
+
+In Perl 5.8.0 there were about 69000 separate tests in about 700 test files,
+in Perl 5.8.1 there are about 77000 separate tests in about 780 test files.
+The exact numbers depend on the Perl configuration and on the operating
+system platform.
+
+=head1 Known Problems
+
+The hash randomisation mentioned in L</Incompatible Changes> is definitely
+problematic: it will wake dormant bugs and shake out bad assumptions.
+
+If you want to use mod_perl 2.x with Perl 5.8.1, you will need
+mod_perl-1.99_10 or higher. Earlier versions of mod_perl 2.x
+do not work with the randomised hashes. (mod_perl 1.x works fine.)
+You will also need Apache::Test 1.04 or higher.
+
+Many of the rarer platforms that worked 100% or pretty close to it
+with perl 5.8.0 have been left a little bit untended since their
+maintainers have been otherwise busy lately, and therefore there will
+be more failures on those platforms. Such platforms include Mac OS
+Classic, IBM z/OS (and other EBCDIC platforms), and NetWare. The most
+common Perl platforms (Unix and Unix-like, Microsoft platforms, and
+VMS) have large enough testing and expert population that they are
+doing well.
+
+=head2 Tied hashes in scalar context
+
+Tied hashes do not currently return anything useful in scalar context,
+for example when used as boolean tests:
+
+ if (%tied_hash) { ... }
+
+The current nonsensical behaviour is always to return false,
+regardless of whether the hash is empty or has elements.
+
+The root cause is that there is no interface for the implementors of
+tied hashes to implement the behaviour of a hash in scalar context.
+
+=head2 Net::Ping 450_service and 510_ping_udp failures
+
+The subtests 9 and 18 of lib/Net/Ping/t/450_service.t, and the
+subtest 2 of lib/Net/Ping/t/510_ping_udp.t might fail if you have
+an unusual networking setup. For example in the latter case the
+test is trying to send a UDP ping to the IP address 127.0.0.1.
+
+=head2 B::C
+
+The C-generating compiler backend B::C (the frontend being
+C<perlcc -c>) is even more broken than it used to be because of
+the extensive lexical variable changes. (The good news is that
+B::Bytecode and ByteLoader are better than they used to be.)
+
+=head1 Platform Specific Problems
+
+=head2 EBCDIC Platforms
+
+IBM z/OS and other EBCDIC platforms continue to be problematic
+regarding Unicode support. Many Unicode tests are skipped when
+they really should be fixed.
+
+=head2 Cygwin 1.5 problems
+
+In Cygwin 1.5 the F<io/tell> and F<op/sysio> tests have failures for
+some yet unknown reason. In 1.5.5 the threads tests stress_cv,
+stress_re, and stress_string are failing unless the environment
+variable PERLIO is set to "perlio" (which makes also the io/tell
+failure go away).
+
+Perl 5.8.1 does build and work well with Cygwin 1.3: with (uname -a)
+C<CYGWIN_NT-5.0 ... 1.3.22(0.78/3/2) 2003-03-18 09:20 i686 ...>
+a 100% "make test" was achieved with C<Configure -des -Duseithreads>.
+
+=head2 HP-UX: HP cc warnings about sendfile and sendpath
+
+With certain HP C compiler releases (e.g. B.11.11.02) you will
+get many warnings like this (lines wrapped for easier reading):
+
+ cc: "/usr/include/sys/socket.h", line 504: warning 562:
+ Redeclaration of "sendfile" with a different storage class specifier:
+ "sendfile" will have internal linkage.
+ cc: "/usr/include/sys/socket.h", line 505: warning 562:
+ Redeclaration of "sendpath" with a different storage class specifier:
+ "sendpath" will have internal linkage.
+
+The warnings show up both during the build of Perl and during certain
+lib/ExtUtils tests that invoke the C compiler. The warning, however,
+is not serious and can be ignored.
+
+=head2 IRIX: t/uni/tr_7jis.t falsely failing
+
+The test t/uni/tr_7jis.t is known to report failure under 'make test'
+or the test harness with certain releases of IRIX (at least IRIX 6.5
+and MIPSpro Compilers Version 7.3.1.1m), but if run manually the test
+fully passes.
+
+=head2 Mac OS X: no usemymalloc
+
+The Perl malloc (C<-Dusemymalloc>) does not work at all in Mac OS X.
+This is not that serious, though, since the native malloc works just
+fine.
+
+=head2 Tru64: No threaded builds with GNU cc (gcc)
+
+In the latest Tru64 releases (e.g. v5.1B or later) gcc cannot be used
+to compile a threaded Perl (-Duseithreads) because the system
+C<< <pthread.h> >> file doesn't know about gcc.
+
+=head2 Win32: sysopen, sysread, syswrite
+
+As of the 5.8.0 release, sysopen()/sysread()/syswrite() do not behave
+like they used to in 5.6.1 and earlier with respect to "text" mode.
+These built-ins now always operate in "binary" mode (even if sysopen()
+was passed the O_TEXT flag, or if binmode() was used on the file
+handle). Note that this issue should only make a difference for disk
+files, as sockets and pipes have always been in "binary" mode in the
+Windows port. As this behavior is currently considered a bug,
+compatible behavior may be re-introduced in a future release. Until
+then, the use of sysopen(), sysread() and syswrite() is not supported
+for "text" mode operations.
+
+=head1 Future Directions
+
+The following things B<might> happen in future. The first publicly
+available releases having these characteristics will be the developer
+releases Perl 5.9.x, culminating in the Perl 5.10.0 release. These
+are our best guesses at the moment: we reserve the right to rethink.
+
+=over 4
+
+=item *
+
+PerlIO will become The Default. Currently (in Perl 5.8.x) the stdio
+library is still used if Perl thinks it can use certain tricks to
+make stdio go B<really> fast. For future releases our goal is to
+make PerlIO go even faster.
+
+=item *
+
+A new feature called I<assertions> will be available. This means that
+one can have code called assertions sprinkled in the code: usually
+they are optimised away, but they can be enabled with the C<-A> option.
+
+=item *
+
+A new operator C<//> (defined-or) will be available. This means that
+one will be able to say
+
+ $a // $b
+
+instead of
+
+ defined $a ? $a : $b
+
+and
+
+ $c //= $d;
+
+instead of
+
+ $c = $d unless defined $c;
+
+The operator will have the same precedence and associativity as C<||>.
+A source code patch against the Perl 5.8.1 sources will be available
+in CPAN as F<authors/id/H/HM/HMBRAND/dor-5.8.1.diff>.
+
+=item *
+
+C<unpack()> will default to unpacking the C<$_>.
+
+=item *
+
+Various Copy-On-Write techniques will be investigated in hopes
+of speeding up Perl.
+
+=item *
+
+CPANPLUS, Inline, and Module::Build will become core modules.
+
+=item *
+
+The ability to write true lexically scoped pragmas will be introduced.
+
+=item *
+
+Work will continue on the bytecompiler and byteloader.
+
+=item *
+
+v-strings as they currently exist are scheduled to be deprecated. The
+v-less form (1.2.3) will become a "version object" when used with C<use>,
+C<require>, and C<$VERSION>. $^V will also be a "version object" so the
+printf("%vd",...) construct will no longer be needed. The v-ful version
+(v1.2.3) will become obsolete. The equivalence of strings and v-strings (e.g.
+that currently 5.8.0 is equal to "\5\8\0") will go away. B<There may be no
+deprecation warning for v-strings>, though: it is quite hard to detect when
+v-strings are being used safely, and when they are not.
+
+=item *
+
+5.005 Threads Will Be Removed
+
+=item *
+
+The C<$*> Variable Will Be Removed
+(it was deprecated a long time ago)
+
+=item *
+
+Pseudohashes Will Be Removed
+
+=back
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ . There may also be
+information at http://www.perl.com/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl582delta.pod b/Master/tlpkg/tlperl/lib/pods/perl582delta.pod
new file mode 100644
index 00000000000..87080702ac8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl582delta.pod
@@ -0,0 +1,162 @@
+=head1 NAME
+
+perl582delta - what is new for perl v5.8.2
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.1 release and
+the 5.8.2 release.
+
+If you are upgrading from an earlier release such as 5.6.1, first read
+the L<perl58delta>, which describes differences between 5.6.0 and
+5.8.0, and the L<perl581delta>, which describes differences between
+5.8.0 and 5.8.1.
+
+=head1 Incompatible Changes
+
+For threaded builds for modules calling certain re-entrant system calls,
+binary compatibility was accidentally lost between 5.8.0 and 5.8.1.
+Binary compatibility with 5.8.0 has been restored in 5.8.2, which
+necessitates breaking compatibility with 5.8.1. We see this as the
+lesser of two evils.
+
+This will only affect people who have a threaded perl 5.8.1, and compiled
+modules which use these calls, and now attempt to run the compiled modules
+with 5.8.2. The fix is to re-compile and re-install the modules using 5.8.2.
+
+=head1 Core Enhancements
+
+=head2 Hash Randomisation
+
+The hash randomisation introduced with 5.8.1 has been amended. It
+transpired that although the implementation introduced in 5.8.1 was source
+compatible with 5.8.0, it was not binary compatible in certain cases. 5.8.2
+contains an improved implementation which is both source and binary
+compatible with both 5.8.0 and 5.8.1, and remains robust against the form of
+attack which prompted the change for 5.8.1.
+
+We are grateful to the Debian project for their input in this area.
+See L<perlsec/"Algorithmic Complexity Attacks"> for the original
+rationale behind this change.
+
+=head2 Threading
+
+Several memory leaks associated with variables shared between threads
+have been fixed.
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules And Pragmata
+
+The following modules and pragmata have been updated since Perl 5.8.1:
+
+=over 4
+
+=item Devel::PPPort
+
+=item Digest::MD5
+
+=item I18N::LangTags
+
+=item libnet
+
+=item MIME::Base64
+
+=item Pod::Perldoc
+
+=item strict
+
+Documentation improved
+
+=item Tie::Hash
+
+Documentation improved
+
+=item Time::HiRes
+
+=item Unicode::Collate
+
+=item Unicode::Normalize
+
+=item UNIVERSAL
+
+Documentation improved
+
+=back
+
+=head1 Selected Bug Fixes
+
+Some syntax errors involving unrecognized filetest operators are now handled
+correctly by the parser.
+
+=head1 Changed Internals
+
+Interpreter initialization is more complete when -DMULTIPLICITY is off.
+This should resolve problems with initializing and destroying the Perl
+interpreter more than once in a single process.
+
+=head1 Platform Specific Problems
+
+Dynamic linker flags have been tweaked for Solaris and OS X, which should
+solve problems seen while building some XS modules.
+
+Bugs in OS/2 sockets and tmpfile have been fixed.
+
+In OS X C<setreuid> and friends are troublesome - perl will now work
+around their problems as best possible.
+
+=head1 Future Directions
+
+Starting with 5.8.3 we intend to make more frequent maintenance releases,
+with a smaller number of changes in each. The intent is to propagate
+bug fixes out to stable releases more rapidly and make upgrading stable
+releases less of an upheaval. This should give end users more
+flexibility in their choice of upgrade timing, and allow them easier
+assessment of the impact of upgrades. The current plan is for code freezes
+as follows
+
+=over 4
+
+=item *
+
+5.8.3 23:59:59 GMT, Wednesday December 31st 2003
+
+=item *
+
+5.8.4 23:59:59 GMT, Wednesday March 31st 2004
+
+=item *
+
+5.8.5 23:59:59 GMT, Wednesday June 30th 2004
+
+=back
+
+with the release following soon after, when testing is complete.
+
+See L<perl581delta/"Future Directions"> for more soothsaying.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/. There may also be
+information at http://www.perl.com/, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl583delta.pod b/Master/tlpkg/tlperl/lib/pods/perl583delta.pod
new file mode 100644
index 00000000000..2981a9834a8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl583delta.pod
@@ -0,0 +1,210 @@
+=head1 NAME
+
+perl583delta - what is new for perl v5.8.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.2 release and
+the 5.8.3 release.
+
+If you are upgrading from an earlier release such as 5.6.1, first read
+the L<perl58delta>, which describes differences between 5.6.0 and
+5.8.0, and the L<perl581delta> and L<perl582delta>, which describe differences
+between 5.8.0, 5.8.1 and 5.8.2
+
+=head1 Incompatible Changes
+
+There are no changes incompatible with 5.8.2.
+
+=head1 Core Enhancements
+
+A C<SCALAR> method is now available for tied hashes. This is called when
+a tied hash is used in scalar context, such as
+
+ if (%tied_hash) {
+ ...
+ }
+
+
+The old behaviour was that %tied_hash would return whatever would have been
+returned for that hash before the hash was tied (so usually 0). The new
+behaviour in the absence of a SCALAR method is to return TRUE if in the
+middle of an C<each> iteration, and otherwise call FIRSTKEY to check if the
+hash is empty (making sure that a subsequent C<each> will also begin by
+calling FIRSTKEY). Please see L<perltie/SCALAR> for the full details and
+caveats.
+
+=head1 Modules and Pragmata
+
+=over 4
+
+=item CGI
+
+=item Cwd
+
+=item Digest
+
+=item Digest::MD5
+
+=item Encode
+
+=item File::Spec
+
+=item FindBin
+
+A function C<again> is provided to resolve problems where modules in different
+directories wish to use FindBin.
+
+=item List::Util
+
+You can now weaken references to read only values.
+
+=item Math::BigInt
+
+=item PodParser
+
+=item Pod::Perldoc
+
+=item POSIX
+
+=item Unicode::Collate
+
+=item Unicode::Normalize
+
+=item Test::Harness
+
+=item threads::shared
+
+C<cond_wait> has a new two argument form. C<cond_timedwait> has been added.
+
+=back
+
+=head1 Utility Changes
+
+C<find2perl> now assumes C<-print> as a default action. Previously, it
+needed to be specified explicitly.
+
+A new utility, C<prove>, makes it easy to run an individual regression test
+at the command line. C<prove> is part of Test::Harness, which users of earlier
+Perl versions can install from CPAN.
+
+=head1 New Documentation
+
+The documentation has been revised in places to produce more standard manpages.
+
+The documentation for the special code blocks (BEGIN, CHECK, INIT, END)
+has been improved.
+
+=head1 Installation and Configuration Improvements
+
+Perl now builds on OpenVMS I64
+
+=head1 Selected Bug Fixes
+
+Using substr() on a UTF8 string could cause subsequent accesses on that
+string to return garbage. This was due to incorrect UTF8 offsets being
+cached, and is now fixed.
+
+join() could return garbage when the same join() statement was used to
+process 8 bit data having earlier processed UTF8 data, due to the flags
+on that statement's temporary workspace not being reset correctly. This
+is now fixed.
+
+C<$a .. $b> will now work as expected when either $a or $b is C<undef>
+
+Using Unicode keys with tied hashes should now work correctly.
+
+Reading $^E now preserves $!. Previously, the C code implementing $^E
+did not preserve C<errno>, so reading $^E could cause C<errno> and therefore
+C<$!> to change unexpectedly.
+
+Reentrant functions will (once more) work with C++. 5.8.2 introduced a bugfix
+which accidentally broke the compilation of Perl extensions written in C++
+
+=head1 New or Changed Diagnostics
+
+The fatal error "DESTROY created new reference to dead object" is now
+documented in L<perldiag>.
+
+=head1 Changed Internals
+
+The hash code has been refactored to reduce source duplication. The
+external interface is unchanged, and aside from the bug fixes described
+above, there should be no change in behaviour.
+
+C<hv_clear_placeholders> is now part of the perl API
+
+Some C macros have been tidied. In particular macros which create temporary
+local variables now name these variables more defensively, which should
+avoid bugs where names clash.
+
+<signal.h> is now always included.
+
+=head1 Configuration and Building
+
+C<Configure> now invokes callbacks regardless of the value of the variable
+they are called for. Previously callbacks were only invoked in the
+C<case $variable $define)> branch. This change should only affect platform
+maintainers writing configuration hints files.
+
+=head1 Platform Specific Problems
+
+The regression test ext/threads/shared/t/wait.t fails on early RedHat 9
+and HP-UX 10.20 due to bugs in their threading implementations.
+RedHat users should see https://rhn.redhat.com/errata/RHBA-2003-136.html
+and consider upgrading their glibc.
+
+=head1 Known Problems
+
+Detached threads aren't supported on Windows yet, as they may lead to
+memory access violation problems.
+
+There is a known race condition opening scripts in C<suidperl>. C<suidperl>
+is neither built nor installed by default, and has been deprecated since
+perl 5.8.0. You are advised to replace use of suidperl with tools such
+as sudo ( http://www.courtesan.com/sudo/ )
+
+We have a backlog of unresolved bugs. Dealing with bugs and bug reports
+is unglamorous work; not something ideally suited to volunteer labour,
+but that is all that we have.
+
+The perl5 development team are implementing changes to help address this
+problem, which should go live in early 2004.
+
+=head1 Future Directions
+
+Code freeze for the next maintenance release (5.8.4) is on March 31st 2004,
+with release expected by mid April. Similarly 5.8.5's freeze will be at
+the end of June, with release by mid July.
+
+=head1 Obituary
+
+Iain 'Spoon' Truskett, Perl hacker, author of L<perlreref> and
+contributor to CPAN, died suddenly on 29th December 2003, aged 24.
+He will be missed.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl584delta.pod b/Master/tlpkg/tlperl/lib/pods/perl584delta.pod
new file mode 100644
index 00000000000..b2cdcc6b822
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl584delta.pod
@@ -0,0 +1,263 @@
+=head1 NAME
+
+perl584delta - what is new for perl v5.8.4
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.3 release and
+the 5.8.4 release.
+
+=head1 Incompatible Changes
+
+Many minor bugs have been fixed. Scripts which happen to rely on previously
+erroneous behaviour will consider these fixes as incompatible changes :-)
+You are advised to perform sufficient acceptance testing on this release
+to satisfy yourself that this does not affect you, before putting this
+release into production.
+
+The diagnostic output of Carp has been changed slightly, to add a space after
+the comma between arguments. This makes it much easier for tools such as
+web browsers to wrap it, but might confuse any automatic tools which perform
+detailed parsing of Carp output.
+
+The internal dump output has been improved, so that non-printable characters
+such as newline and backspace are output in C<\x> notation, rather than
+octal. This might just confuse non-robust tools which parse the output of
+modules such as Devel::Peek.
+
+=head1 Core Enhancements
+
+=head2 Malloc wrapping
+
+Perl can now be built to detect attempts to assign pathologically large chunks
+of memory. Previously such assignments would suffer from integer wrap-around
+during size calculations causing a misallocation, which would crash perl, and
+could theoretically be used for "stack smashing" attacks. The wrapping
+defaults to enabled on platforms where we know it works (most AIX
+configurations, BSDi, Darwin, DEC OSF/1, FreeBSD, HP/UX, GNU Linux, OpenBSD,
+Solaris, VMS and most Win32 compilers) and defaults to disabled on other
+platforms.
+
+=head2 Unicode Character Database 4.0.1
+
+The copy of the Unicode Character Database included in Perl 5.8 has
+been updated to 4.0.1 from 4.0.0.
+
+=head2 suidperl less insecure
+
+Paul Szabo has analysed and patched C<suidperl> to remove existing known
+insecurities. Currently there are no known holes in C<suidperl>, but previous
+experience shows that we cannot be confident that these were the last. You may
+no longer invoke the set uid perl directly, so to preserve backwards
+compatibility with scripts that invoke #!/usr/bin/suidperl the only set uid
+binary is now C<sperl5.8.>I<n> (C<sperl5.8.4> for this release). C<suidperl>
+is installed as a hard link to C<perl>; both C<suidperl> and C<perl> will
+invoke C<sperl5.8.4> automatically the set uid binary, so this change should
+be completely transparent.
+
+For new projects the core perl team would strongly recommend that you use
+dedicated, single purpose security tools such as C<sudo> in preference to
+C<suidperl>.
+
+=head2 format
+
+In addition to bug fixes, C<format>'s features have been enhanced. See
+L<perlform>
+
+=head1 Modules and Pragmata
+
+The (mis)use of C</tmp> in core modules and documentation has been tidied up.
+Some modules available both within the perl core and independently from CPAN
+("dual-life modules") have not yet had these changes applied; the changes
+will be integrated into future stable perl releases as the modules are
+updated on CPAN.
+
+=head2 Updated modules
+
+=over 4
+
+=item Attribute::Handlers
+
+=item B
+
+=item Benchmark
+
+=item CGI
+
+=item Carp
+
+=item Cwd
+
+=item Exporter
+
+=item File::Find
+
+=item IO
+
+=item IPC::Open3
+
+=item Local::Maketext
+
+=item Math::BigFloat
+
+=item Math::BigInt
+
+=item Math::BigRat
+
+=item MIME::Base64
+
+=item ODBM_File
+
+=item POSIX
+
+=item Shell
+
+=item Socket
+
+There is experimental support for Linux abstract Unix domain sockets.
+
+=item Storable
+
+=item Switch
+
+Synced with its CPAN version 2.10
+
+=item Sys::Syslog
+
+C<syslog()> can now use numeric constants for facility names and priorities,
+in addition to strings.
+
+=item Term::ANSIColor
+
+=item Time::HiRes
+
+=item Unicode::UCD
+
+=item Win32
+
+Win32.pm/Win32.xs has moved from the libwin32 module to core Perl
+
+=item base
+
+=item open
+
+=item threads
+
+Detached threads are now also supported on Windows.
+
+=item utf8
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Accelerated Unicode case mappings (C</i>, C<lc>, C<uc>, etc).
+
+=item *
+
+In place sort optimised (eg C<@a = sort @a>)
+
+=item *
+
+Unnecessary assignment optimised away in
+
+ my $s = undef;
+ my @a = ();
+ my %h = ();
+
+=item *
+
+Optimised C<map> in scalar context
+
+=back
+
+=head1 Utility Changes
+
+The Perl debugger (F<lib/perl5db.pl>) can now save all debugger commands for
+sourcing later, and can display the parent inheritance tree of a given class.
+
+=head1 Installation and Configuration Improvements
+
+The build process on both VMS and Windows has had several minor improvements
+made. On Windows Borland's C compiler can now compile perl with PerlIO and/or
+USE_LARGE_FILES enabled.
+
+C<perl.exe> on Windows now has a "Camel" logo icon. The use of a camel with
+the topic of Perl is a trademark of O'Reilly and Associates Inc., and is used
+with their permission (ie distribution of the source, compiling a Windows
+executable from it, and using that executable locally). Use of the supplied
+camel for anything other than a perl executable's icon is specifically not
+covered, and anyone wishing to redistribute perl binaries I<with> the icon
+should check directly with O'Reilly beforehand.
+
+Perl should build cleanly on Stratus VOS once more.
+
+=head1 Selected Bug Fixes
+
+More utf8 bugs fixed, notably in how C<chomp>, C<chop>, C<send>, and
+C<syswrite> and interact with utf8 data. Concatenation now works correctly
+when C<use bytes;> is in scope.
+
+Pragmata are now correctly propagated into (?{...}) constructions in regexps.
+Code such as
+
+ my $x = qr{ ... (??{ $x }) ... };
+
+will now (correctly) fail under use strict. (As the inner C<$x> is and
+has always referred to C<$::x>)
+
+The "const in void context" warning has been suppressed for a constant in an
+optimised-away boolean expression such as C<5 || print;>
+
+C<perl -i> could C<fchmod(stdin)> by mistake. This is serious if stdin is
+attached to a terminal, and perl is running as root. Now fixed.
+
+=head1 New or Changed Diagnostics
+
+C<Carp> and the internal diagnostic routines used by C<Devel::Peek> have been
+made clearer, as described in L</Incompatible Changes>
+
+=head1 Changed Internals
+
+Some bugs have been fixed in the hash internals. Restricted hashes and
+their place holders are now allocated and deleted at slightly different times,
+but this should not be visible to user code.
+
+=head1 Future Directions
+
+Code freeze for the next maintenance release (5.8.5) will be on 30th June
+2004, with release by mid July.
+
+=head1 Platform Specific Problems
+
+This release is known not to build on Windows 95.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl585delta.pod b/Master/tlpkg/tlperl/lib/pods/perl585delta.pod
new file mode 100644
index 00000000000..1717c74e028
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl585delta.pod
@@ -0,0 +1,257 @@
+=head1 NAME
+
+perl585delta - what is new for perl v5.8.5
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.4 release and
+the 5.8.5 release.
+
+=head1 Incompatible Changes
+
+There are no changes incompatible with 5.8.4.
+
+=head1 Core Enhancements
+
+Perl's regular expression engine now contains support for matching on the
+intersection of two Unicode character classes. You can also now refer to
+user-defined character classes from within other user defined character
+classes.
+
+=head1 Modules and Pragmata
+
+=over 4
+
+=item *
+
+Carp improved to work nicely with Safe. Carp's message reporting should now
+be anomaly free - it will always print out line number information.
+
+=item *
+
+CGI upgraded to version 3.05
+
+=item *
+
+charnames now avoids clobbering $_
+
+=item *
+
+Digest upgraded to version 1.08
+
+=item *
+
+Encode upgraded to version 2.01
+
+=item *
+
+FileCache upgraded to version 1.04
+
+=item *
+
+libnet upgraded to version 1.19
+
+=item *
+
+Pod::Parser upgraded to version 1.28
+
+=item *
+
+Pod::Perldoc upgraded to version 3.13
+
+=item *
+
+Pod::LaTeX upgraded to version 0.57
+
+=item *
+
+Safe now works properly with Carp
+
+=item *
+
+Scalar-List-Utils upgraded to version 1.14
+
+=item *
+
+Shell's documentation has been re-written, and its historical partial
+auto-quoting of command arguments can now be disabled.
+
+=item *
+
+Test upgraded to version 1.25
+
+=item *
+
+Test::Harness upgraded to version 2.42
+
+=item *
+
+Time::Local upgraded to version 1.10
+
+=item *
+
+Unicode::Collate upgraded to version 0.40
+
+=item *
+
+Unicode::Normalize upgraded to version 0.30
+
+=back
+
+=head1 Utility Changes
+
+=head2 Perl's debugger
+
+The debugger can now emulate stepping backwards, by restarting and rerunning
+all bar the last command from a saved command history.
+
+=head2 h2ph
+
+F<h2ph> is now able to understand a very limited set of C inline functions
+-- basically, the inline functions that look like CPP macros. This has
+been introduced to deal with some of the headers of the newest versions of
+the glibc. The standard warning still applies; to quote F<h2ph>'s
+documentation, I<you may need to dicker with the files produced>.
+
+=head1 Installation and Configuration Improvements
+
+Perl 5.8.5 should build cleanly from source on LynxOS.
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+The in-place sort optimisation introduced in 5.8.4 had a bug. For example,
+in code such as
+
+ @a = sort ($b, @a)
+
+the result would omit the value $b. This is now fixed.
+
+=item *
+
+The optimisation for unnecessary assignments introduced in 5.8.4 could give
+spurious warnings. This has been fixed.
+
+=item *
+
+Perl should now correctly detect and read BOM-marked and (BOMless) UTF-16
+scripts of either endianness.
+
+=item *
+
+Creating a new thread when weak references exist was buggy, and would often
+cause warnings at interpreter destruction time. The known bug is now fixed.
+
+=item *
+
+Several obscure bugs involving manipulating Unicode strings with C<substr> have
+been fixed.
+
+=item *
+
+Previously if Perl's file globbing function encountered a directory that it
+did not have permission to open it would return immediately, leading to
+unexpected truncation of the list of results. This has been fixed, to be
+consistent with Unix shells' globbing behaviour.
+
+=item *
+
+Thread creation time could vary wildly between identical runs. This was caused
+by a poor hashing algorithm in the thread cloning routines, which has now
+been fixed.
+
+=item *
+
+The internals of the ithreads implementation were not checking if OS-level
+thread creation had failed. threads->create() now returns C<undef> in if
+thread creation fails instead of crashing perl.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item *
+
+Perl -V has several improvements
+
+=over 4
+
+=item *
+
+correctly outputs local patch names that contain embedded code snippets
+or other characters that used to confuse it.
+
+=item *
+
+arguments to -V that look like regexps will give multiple lines of output.
+
+=item *
+
+a trailing colon suppresses the linefeed and ';' terminator, allowing
+embedding of queries into shell commands.
+
+=item *
+
+a leading colon removes the 'name=' part of the response, allowing mapping to
+any name.
+
+=back
+
+=item *
+
+When perl fails to find the specified script, it now outputs a second line
+suggesting that the user use the C<-S> flag:
+
+ $ perl5.8.5 missing.pl
+ Can't open perl script "missing.pl": No such file or directory.
+ Use -S to search $PATH for it.
+
+=back
+
+=head1 Changed Internals
+
+The Unicode character class files used by the regular expression engine are
+now built at build time from the supplied Unicode consortium data files,
+instead of being shipped prebuilt. This makes the compressed Perl source
+tarball about 200K smaller. A side effect is that the layout of files inside
+lib/unicore has changed.
+
+=head1 Known Problems
+
+The regression test F<t/uni/class.t> is now performing considerably more
+tests, and can take several minutes to run even on a fast machine.
+
+=head1 Platform Specific Problems
+
+This release is known not to build on Windows 95.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl586delta.pod b/Master/tlpkg/tlperl/lib/pods/perl586delta.pod
new file mode 100644
index 00000000000..6cd0fa85496
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl586delta.pod
@@ -0,0 +1,170 @@
+=head1 NAME
+
+perl586delta - what is new for perl v5.8.6
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.5 release and
+the 5.8.6 release.
+
+=head1 Incompatible Changes
+
+There are no changes incompatible with 5.8.5.
+
+=head1 Core Enhancements
+
+The perl interpreter is now more tolerant of UTF-16-encoded scripts.
+
+On Win32, Perl can now use non-IFS compatible LSPs, which allows Perl to
+work in conjunction with firewalls such as McAfee Guardian. For full details
+see the file F<README.win32>, particularly if you're running Win95.
+
+=head1 Modules and Pragmata
+
+=over 4
+
+=item *
+
+With the C<base> pragma, an intermediate class with no fields used to messes
+up private fields in the base class. This has been fixed.
+
+=item *
+
+Cwd upgraded to version 3.01 (as part of the new PathTools distribution)
+
+=item *
+
+Devel::PPPort upgraded to version 3.03
+
+=item *
+
+File::Spec upgraded to version 3.01 (as part of the new PathTools distribution)
+
+=item *
+
+Encode upgraded to version 2.08
+
+=item *
+
+ExtUtils::MakeMaker remains at version 6.17, as later stable releases currently
+available on CPAN have some issues with core modules on some core platforms.
+
+=item *
+
+I18N::LangTags upgraded to version 0.35
+
+=item *
+
+Math::BigInt upgraded to version 1.73
+
+=item *
+
+Math::BigRat upgraded to version 0.13
+
+=item *
+
+MIME::Base64 upgraded to version 3.05
+
+=item *
+
+POSIX::sigprocmask function can now retrieve the current signal mask without
+also setting it.
+
+=item *
+
+Time::HiRes upgraded to version 1.65
+
+=back
+
+=head1 Utility Changes
+
+Perl has a new -dt command-line flag, which enables threads support in the
+debugger.
+
+=head1 Performance Enhancements
+
+C<reverse sort ...> is now optimized to sort in reverse, avoiding the
+generation of a temporary intermediate list.
+
+C<for (reverse @foo)> now iterates in reverse, avoiding the generation of a
+temporary reversed list.
+
+=head1 Selected Bug Fixes
+
+The regexp engine is now more robust when given invalid utf8 input, as is
+sometimes generated by buggy XS modules.
+
+C<foreach> on threads::shared array used to be able to crash Perl. This bug
+has now been fixed.
+
+A regexp in C<STDOUT>'s destructor used to coredump, because the regexp pad
+was already freed. This has been fixed.
+
+C<goto &> is now more robust - bugs in deep recursion and chained C<goto &>
+have been fixed.
+
+Using C<delete> on an array no longer leaks memory. A C<pop> of an item from a
+shared array reference no longer causes a leak.
+
+C<eval_sv()> failing a taint test could corrupt the stack - this has been
+fixed.
+
+On platforms with 64 bit pointers numeric comparison operators used to
+erroneously compare the addresses of references that are overloaded, rather
+than using the overloaded values. This has been fixed.
+
+C<read> into a UTF8-encoded buffer with an offset off the end of the buffer
+no longer mis-calculates buffer lengths.
+
+Although Perl has promised since version 5.8 that C<sort()> would be
+stable, the two cases C<sort {$b cmp $a}> and C<< sort {$b <=> $a} >> could
+produce non-stable sorts. This is corrected in perl5.8.6.
+
+Localising C<$^D> no longer generates a diagnostic message about valid -D
+flags.
+
+=head1 New or Changed Diagnostics
+
+For -t and -T,
+ Too late for "-T" option
+has been changed to the more informative
+ "-T" is on the #! line, it must also be used on the command line
+
+=head1 Changed Internals
+
+From now on all applications embedding perl will behave as if perl
+were compiled with -DPERL_USE_SAFE_PUTENV. See "Environment access" in
+the F<INSTALL> file for details.
+
+Most C<C> source files now have comments at the top explaining their purpose,
+which should help anyone wishing to get an overview of the implementation.
+
+=head1 New Tests
+
+There are significantly more tests for the C<B> suite of modules.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl587delta.pod b/Master/tlpkg/tlperl/lib/pods/perl587delta.pod
new file mode 100644
index 00000000000..34ee8f21724
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl587delta.pod
@@ -0,0 +1,379 @@
+=head1 NAME
+
+perl587delta - what is new for perl v5.8.7
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.6 release and
+the 5.8.7 release.
+
+=head1 Incompatible Changes
+
+There are no changes incompatible with 5.8.6.
+
+=head1 Core Enhancements
+
+=head2 Unicode Character Database 4.1.0
+
+The copy of the Unicode Character Database included in Perl 5.8 has
+been updated to 4.1.0 from 4.0.1. See
+L<http://www.unicode.org/versions/Unicode4.1.0/#NotableChanges> for the
+notable changes.
+
+=head2 suidperl less insecure
+
+A pair of exploits in C<suidperl> involving debugging code have been closed.
+
+For new projects the core perl team strongly recommends that you use
+dedicated, single purpose security tools such as C<sudo> in preference to
+C<suidperl>.
+
+=head2 Optional site customization script
+
+The perl interpreter can be built to allow the use of a site customization
+script. By default this is not enabled, to be consistent with previous perl
+releases. To use this, add C<-Dusesitecustomize> to the command line flags
+when running the C<Configure> script. See also L<perlrun/-f>.
+
+=head2 C<Config.pm> is now much smaller.
+
+C<Config.pm> is now about 3K rather than 32K, with the infrequently used
+code and C<%Config> values loaded on demand. This is transparent to the
+programmer, but means that most code will save parsing and loading 29K of
+script (for example, code that uses C<File::Find>).
+
+=head1 Modules and Pragmata
+
+=over 4
+
+=item *
+
+B upgraded to version 1.09
+
+=item *
+
+base upgraded to version 2.07
+
+=item *
+
+bignum upgraded to version 0.17
+
+=item *
+
+bytes upgraded to version 1.02
+
+=item *
+
+Carp upgraded to version 1.04
+
+=item *
+
+CGI upgraded to version 3.10
+
+=item *
+
+Class::ISA upgraded to version 0.33
+
+=item *
+
+Data::Dumper upgraded to version 2.121_02
+
+=item *
+
+DB_File upgraded to version 1.811
+
+=item *
+
+Devel::PPPort upgraded to version 3.06
+
+=item *
+
+Digest upgraded to version 1.10
+
+=item *
+
+Encode upgraded to version 2.10
+
+=item *
+
+FileCache upgraded to version 1.05
+
+=item *
+
+File::Path upgraded to version 1.07
+
+=item *
+
+File::Temp upgraded to version 0.16
+
+=item *
+
+IO::File upgraded to version 1.11
+
+=item *
+
+IO::Socket upgraded to version 1.28
+
+=item *
+
+Math::BigInt upgraded to version 1.77
+
+=item *
+
+Math::BigRat upgraded to version 0.15
+
+=item *
+
+overload upgraded to version 1.03
+
+=item *
+
+PathTools upgraded to version 3.05
+
+=item *
+
+Pod::HTML upgraded to version 1.0503
+
+=item *
+
+Pod::Perldoc upgraded to version 3.14
+
+=item *
+
+Pod::LaTeX upgraded to version 0.58
+
+=item *
+
+Pod::Parser upgraded to version 1.30
+
+=item *
+
+Symbol upgraded to version 1.06
+
+=item *
+
+Term::ANSIColor upgraded to version 1.09
+
+=item *
+
+Test::Harness upgraded to version 2.48
+
+=item *
+
+Test::Simple upgraded to version 0.54
+
+=item *
+
+Text::Wrap upgraded to version 2001.09293, to fix a bug when wrap() was
+called with a non-space separator.
+
+=item *
+
+threads::shared upgraded to version 0.93
+
+=item *
+
+Time::HiRes upgraded to version 1.66
+
+=item *
+
+Time::Local upgraded to version 1.11
+
+=item *
+
+Unicode::Normalize upgraded to version 0.32
+
+=item *
+
+utf8 upgraded to version 1.05
+
+=item *
+
+Win32 upgraded to version 0.24, which provides Win32::GetFileVersion
+
+=back
+
+=head1 Utility Changes
+
+=head2 find2perl enhancements
+
+C<find2perl> has new options C<-iname>, C<-path> and C<-ipath>.
+
+=head1 Performance Enhancements
+
+The internal pointer mapping hash used during ithreads cloning now uses an
+arena for memory allocation. In tests this reduced ithreads cloning time by
+about 10%.
+
+=head1 Installation and Configuration Improvements
+
+=over 4
+
+=item *
+
+The Win32 "dmake" makefile.mk has been updated to make it compatible
+with the latest versions of dmake.
+
+=item *
+
+C<PERL_MALLOC>, C<DEBUG_MSTATS>, C<PERL_HASH_SEED_EXPLICIT> and C<NO_HASH_SEED>
+should now work in Win32 makefiles.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+The socket() function on Win32 has been fixed so that it is able to use
+transport providers which specify a protocol of 0 (meaning any protocol
+is allowed) once more. (This was broken in 5.8.6, and typically caused
+the use of ICMP sockets to fail.)
+
+=item *
+
+Another obscure bug involving C<substr> and UTF-8 caused by bad internal
+offset caching has been identified and fixed.
+
+=item *
+
+A bug involving the loading of UTF-8 tables by the regexp engine has been
+fixed - code such as C<"\x{100}" =~ /[[:print:]]/> will no longer give
+corrupt results.
+
+=item *
+
+Case conversion operations such as C<uc> on a long Unicode string could
+exhaust memory. This has been fixed.
+
+=item *
+
+C<index>/C<rindex> were buggy for some combinations of Unicode and
+non-Unicode data. This has been fixed.
+
+=item *
+
+C<read> (and presumably C<sysread>) would expose the UTF-8 internals when
+reading from a byte oriented file handle into a UTF-8 scalar. This has
+been fixed.
+
+=item *
+
+Several C<pack>/C<unpack> bug fixes:
+
+=over 4
+
+=item *
+
+Checksums with C<b> or C<B> formats were broken.
+
+=item *
+
+C<unpack> checksums could overflow with the C<C> format.
+
+=item *
+
+C<U0> and C<C0> are now scoped to C<()> C<pack> sub-templates.
+
+=item *
+
+Counted length prefixes now don't change C<C0>/C<U0> mode.
+
+=item *
+
+C<pack> C<Z0> used to destroy the preceding character.
+
+=item *
+
+C<P>/C<p> C<pack> formats used to only recognise literal C<undef>
+
+=back
+
+=item *
+
+Using closures with ithreads could cause perl to crash. This was due to
+failure to correctly lock internal OP structures, and has been fixed.
+
+=item *
+
+The return value of C<close> now correctly reflects any file errors that
+occur while flushing the handle's data, instead of just giving failure if
+the actual underlying file close operation failed.
+
+=item *
+
+C<not() || 1> used to segfault. C<not()> now behaves like C<not(0)>, which was
+the pre 5.6.0 behaviour.
+
+=item *
+
+C<h2ph> has various enhancements to cope with constructs in header files that
+used to result in incorrect or invalid output.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+There is a new taint error, "%ENV is aliased to %s". This error is thrown
+when taint checks are enabled and when C<*ENV> has been aliased, so that
+C<%ENV> has no env-magic anymore and hence the environment cannot be verified
+as taint-free.
+
+The internals of C<pack> and C<unpack> have been updated. All legitimate
+templates should work as before, but there may be some changes in the error
+reported for complex failure cases. Any behaviour changes for non-error cases
+are bugs, and should be reported.
+
+=head1 Changed Internals
+
+There has been a fair amount of refactoring of the C<C> source code, partly to
+make it tidier and more maintainable. The resulting object code and the
+C<perl> binary may well be smaller than 5.8.6, and hopefully faster in some
+cases, but apart from this there should be no user-detectable changes.
+
+C<${^UTF8LOCALE}> has been added to give perl space access to C<PL_utf8locale>.
+
+The size of the arenas used to allocate SV heads and most SV bodies can now
+be changed at compile time. The old size was 1008 bytes, the new default size
+is 4080 bytes.
+
+=head1 Known Problems
+
+Unicode strings returned from overloaded operators can be buggy. This is a
+long standing bug reported since 5.8.6 was released, but we do not yet have
+a suitable fix for it.
+
+=head1 Platform Specific Problems
+
+On UNICOS, lib/Math/BigInt/t/bigintc.t hangs burning CPU.
+ext/B/t/bytecode.t and ext/Socket/t/socketpair.t both fail tests.
+These are unlikely to be resolved, as our valiant UNICOS porter's last
+Cray is being decommissioned.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl588delta.pod b/Master/tlpkg/tlperl/lib/pods/perl588delta.pod
new file mode 100644
index 00000000000..a3d1df35b38
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl588delta.pod
@@ -0,0 +1,1632 @@
+=head1 NAME
+
+perl588delta - what is new for perl v5.8.8
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.7 release and
+the 5.8.8 release.
+
+=head1 Incompatible Changes
+
+There are no changes intentionally incompatible with 5.8.7. If any exist,
+they are bugs and reports are welcome.
+
+=head1 Core Enhancements
+
+=over
+
+=item *
+
+C<chdir>, C<chmod> and C<chown> can now work on filehandles as well as
+filenames, if the system supports respectively C<fchdir>, C<fchmod> and
+C<fchown>, thanks to a patch provided by Gisle Aas.
+
+=back
+
+=head1 Modules and Pragmata
+
+=over
+
+=item *
+
+C<Attribute::Handlers> upgraded to version 0.78_02
+
+=over
+
+=item *
+
+Documentation typo fix
+
+=back
+
+=item *
+
+C<attrs> upgraded to version 1.02
+
+=over
+
+=item *
+
+Internal cleanup only
+
+=back
+
+=item *
+
+C<autouse> upgraded to version 1.05
+
+=over
+
+=item *
+
+Simplified implementation
+
+=back
+
+=item *
+
+C<B> upgraded to version 1.09_01
+
+=over
+
+=item *
+
+The inheritance hierarchy of the C<B::> modules has been corrected;
+C<B::NV> now inherits from C<B::SV> (instead of C<B::IV>).
+
+=back
+
+=item *
+
+C<blib> upgraded to version 1.03
+
+=over
+
+=item *
+
+Documentation typo fix
+
+=back
+
+=item *
+
+C<ByteLoader> upgraded to version 0.06
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<CGI> upgraded to version 3.15
+
+=over
+
+=item *
+
+Extraneous "?" from C<self_url()> removed
+
+=item *
+
+C<scrolling_list()> select attribute fixed
+
+=item *
+
+C<virtual_port> now works properly with the https protocol
+
+=item *
+
+C<upload_hook()> and C<append()> now works in function-oriented mode
+
+=item *
+
+C<POST_MAX> doesn't cause the client to hang any more
+
+=item *
+
+Automatic tab indexes are now disabled and new C<-tabindex> pragma has
+been added to turn automatic indexes back on
+
+=item *
+
+C<end_form()> doesn't emit empty (and non-validating) C<< <div> >>
+
+=item *
+
+C<CGI::Carp> works better in certain mod_perl configurations
+
+=item *
+
+Setting C<$CGI::TMPDIRECTORY> is now effective
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<charnames> upgraded to version 1.05
+
+=over
+
+=item *
+
+C<viacode()> now accept hex strings and has been optimized.
+
+=back
+
+=item *
+
+C<CPAN> upgraded to version 1.76_02
+
+=over
+
+=item *
+
+1 minor bug fix for Win32
+
+=back
+
+=item *
+
+C<Cwd> upgraded to version 3.12
+
+=over
+
+=item *
+
+C<canonpath()> on Win32 now collapses F<foo\..> sections correctly.
+
+=item *
+
+Improved behaviour on Symbian OS.
+
+=item *
+
+Enhanced documentation and typo fixes
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Data::Dumper> upgraded to version 2.121_08
+
+=over
+
+=item *
+
+A problem where C<Data::Dumper> would sometimes update the iterator state
+of hashes has been fixed
+
+=item *
+
+Numeric labels now work
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<DB> upgraded to version 1.01
+
+=over
+
+=item *
+
+A problem where the state of the regexp engine would sometimes get clobbered when running
+under the debugger has been fixed.
+
+=back
+
+=item *
+
+C<DB_File> upgraded to version 1.814
+
+=over
+
+=item *
+
+Adds support for Berkeley DB 4.4.
+
+=back
+
+=item *
+
+C<Devel::DProf> upgraded to version 20050603.00
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Devel::Peek> upgraded to version 1.03
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Devel::PPPort> upgraded to version 3.06_01
+
+=over
+
+=item *
+
+C<--compat-version> argument checking has been improved
+
+=item *
+
+Files passed on the command line are filtered by default
+
+=item *
+
+C<--nofilter> option to override the filtering has been added
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<diagnostics> upgraded to version 1.15
+
+=over
+
+=item *
+
+Documentation typo fix
+
+=back
+
+=item *
+
+C<Digest> upgraded to version 1.14
+
+=over
+
+=item *
+
+The constructor now knows which module implements SHA-224
+
+=item *
+
+Documentation tweaks and typo fixes
+
+=back
+
+=item *
+
+C<Digest::MD5> upgraded to version 2.36
+
+=over
+
+=item *
+
+C<XSLoader> is now used for faster loading
+
+=item *
+
+Enhanced documentation including MD5 weaknesses discovered lately
+
+=back
+
+=item *
+
+C<Dumpvalue> upgraded to version 1.12
+
+=over
+
+=item *
+
+Documentation fix
+
+=back
+
+=item *
+
+C<DynaLoader> upgraded but unfortunately we're not able to increment its version number :-(
+
+=over
+
+=item *
+
+Implements C<dl_unload_file> on Win32
+
+=item *
+
+Internal cleanup
+
+=item *
+
+C<XSLoader> 0.06 incorporated; small optimisation for calling
+C<bootstrap_inherit()> and documentation enhancements.
+
+=back
+
+=item *
+
+C<Encode> upgraded to version 2.12
+
+=over
+
+=item *
+
+A coderef is now acceptable for C<CHECK>!
+
+=item *
+
+3 new characters added to the ISO-8859-7 encoding
+
+=item *
+
+New encoding C<MIME-Header-ISO_2022_JP> added
+
+=item *
+
+Problem with partial characters and C<< encoding(utf-8-strict) >> fixed.
+
+=item *
+
+Documentation enhancements and typo fixes
+
+=back
+
+=item *
+
+C<English> upgraded to version 1.02
+
+=over
+
+=item *
+
+the C<< $COMPILING >> variable has been added
+
+=back
+
+=item *
+
+C<ExtUtils::Constant> upgraded to version 0.17
+
+=over
+
+=item *
+
+Improved compatibility with older versions of perl
+
+=back
+
+=item *
+
+C<ExtUtils::MakeMaker> upgraded to version 6.30 (was 6.17)
+
+=over
+
+=item *
+
+Too much to list here; see L<http://search.cpan.org/dist/ExtUtils-MakeMaker/Changes>
+
+=back
+
+=item *
+
+C<File::Basename> upgraded to version 2.74, with changes contributed by Michael Schwern.
+
+=over
+
+=item *
+
+Documentation clarified and errors corrected.
+
+=item *
+
+C<basename> now strips trailing path separators before processing the name.
+
+=item *
+
+C<basename> now returns C</> for parameter C</>, to make C<basename>
+consistent with the shell utility of the same name.
+
+=item *
+
+The suffix is no longer stripped if it is identical to the remaining characters
+in the name, again for consistency with the shell utility.
+
+=item *
+
+Some internal code cleanup.
+
+=back
+
+=item *
+
+C<File::Copy> upgraded to version 2.09
+
+=over
+
+=item *
+
+Copying a file onto itself used to fail.
+
+=item *
+
+Moving a file between file systems now preserves the access and
+modification time stamps
+
+=back
+
+=item *
+
+C<File::Find> upgraded to version 1.10
+
+=over
+
+=item *
+
+Win32 portability fixes
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<File::Glob> upgraded to version 1.05
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<File::Path> upgraded to version 1.08
+
+=over
+
+=item *
+
+C<mkpath> now preserves C<errno> when C<mkdir> fails
+
+=back
+
+=item *
+
+C<File::Spec> upgraded to version 3.12
+
+=over
+
+=item *
+
+C<File::Spec->rootdir()> now returns C<\> on Win32, instead of C</>
+
+=item *
+
+C<$^O> could sometimes become tainted. This has been fixed.
+
+=item *
+
+C<canonpath> on Win32 now collapses C<foo/..> (or C<foo\..>) sections
+correctly, rather than doing the "misguided" work it was previously doing.
+Note that C<canonpath> on Unix still does B<not> collapse these sections, as
+doing so would be incorrect.
+
+=item *
+
+Some documentation improvements
+
+=item *
+
+Some internal code cleanup
+
+=back
+
+=item *
+
+C<FileCache> upgraded to version 1.06
+
+=over
+
+=item *
+
+POD formatting errors in the documentation fixed
+
+=back
+
+=item *
+
+C<Filter::Simple> upgraded to version 0.82
+
+=item *
+
+C<FindBin> upgraded to version 1.47
+
+=over
+
+=item *
+
+Now works better with directories where access rights are more
+restrictive than usual.
+
+=back
+
+=item *
+
+C<GDBM_File> upgraded to version 1.08
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Getopt::Long> upgraded to version 2.35
+
+=over
+
+=item *
+
+C<prefix_pattern> has now been complemented by a new configuration
+option C<long_prefix_pattern> that allows the user to specify what
+prefix patterns should have long option style semantics applied.
+
+=item *
+
+Options can now take multiple values at once (experimental)
+
+=item *
+
+Various bug fixes
+
+=back
+
+=item *
+
+C<if> upgraded to version 0.05
+
+=over
+
+=item *
+
+Give more meaningful error messages from C<if> when invoked with a
+condition in list context.
+
+=item *
+
+Restore backwards compatibility with earlier versions of perl
+
+=back
+
+=item *
+
+C<IO> upgraded to version 1.22
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<IPC::Open2> upgraded to version 1.02
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<IPC::Open3> upgraded to version 1.02
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<List::Util> upgraded to version 1.18 (was 1.14)
+
+=over
+
+=item *
+
+Fix pure-perl version of C<refaddr> to avoid blessing an un-blessed reference
+
+=item *
+
+Use C<XSLoader> for faster loading
+
+=item *
+
+Fixed various memory leaks
+
+=item *
+
+Internal cleanup and portability fixes
+
+=back
+
+=item *
+
+C<Math::Complex> upgraded to version 1.35
+
+=over
+
+=item *
+
+C<atan2(0, i)> now works, as do all the (computable) complex argument cases
+
+=item *
+
+Fixes for certain bugs in C<make> and C<emake>
+
+=item *
+
+Support returning the I<k>th root directly
+
+=item *
+
+Support C<[2,-3pi/8]> in C<emake>
+
+=item *
+
+Support C<inf> for C<make>/C<emake>
+
+=item *
+
+Document C<make>/C<emake> more visibly
+
+=back
+
+=item *
+
+C<Math::Trig> upgraded to version 1.03
+
+=over
+
+=item *
+
+Add more great circle routines: C<great_circle_waypoint> and
+C<great_circle_destination>
+
+=back
+
+=item *
+
+C<MIME::Base64> upgraded to version 3.07
+
+=over
+
+=item *
+
+Use C<XSLoader> for faster loading
+
+=item *
+
+Enhanced documentation
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<NDBM_File> upgraded to version 1.06
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<ODBM_File> upgraded to version 1.06
+
+=over
+
+=item *
+
+Documentation typo fixed
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Opcode> upgraded to version 1.06
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<open> upgraded to version 1.05
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<overload> upgraded to version 1.04
+
+=over
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<PerlIO> upgraded to version 1.04
+
+=over
+
+=item *
+
+C<PerlIO::via> iterate over layers properly now
+
+=item *
+
+C<PerlIO::scalar> understands C<< $/ = "" >> now
+
+=item *
+
+C<encoding(utf-8-strict)> with partial characters now works
+
+=item *
+
+Enhanced documentation
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Pod::Functions> upgraded to version 1.03
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<Pod::Html> upgraded to version 1.0504
+
+=over
+
+=item *
+
+HTML output will now correctly link
+to C<=item>s on the same page, and should be valid XHTML.
+
+=item *
+
+Variable names are recognized as intended
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<Pod::Parser> upgraded to version 1.32
+
+=over
+
+=item *
+
+Allow files that start with C<=head> on the first line
+
+=item *
+
+Win32 portability fix
+
+=item *
+
+Exit status of C<pod2usage> fixed
+
+=item *
+
+New C<-noperldoc> switch for C<pod2usage>
+
+=item *
+
+Arbitrary URL schemes now allowed
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<POSIX> upgraded to version 1.09
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<re> upgraded to version 0.05
+
+=over
+
+=item *
+
+Documentation typo fixed
+
+=back
+
+=item *
+
+C<Safe> upgraded to version 2.12
+
+=over
+
+=item *
+
+Minor documentation enhancement
+
+=back
+
+=item *
+
+C<SDBM_File> upgraded to version 1.05
+
+=over
+
+=item *
+
+Documentation typo fixed
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Socket> upgraded to version 1.78
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=item *
+
+C<Storable> upgraded to version 2.15
+
+=over
+
+=item *
+
+This includes the C<STORABLE_attach> hook functionality added by
+Adam Kennedy, and more frugal memory requirements when storing under C<ithreads>, by
+using the C<ithreads> cloning tracking code.
+
+=back
+
+=item *
+
+C<Switch> upgraded to version 2.10_01
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<Sys::Syslog> upgraded to version 0.13
+
+=over
+
+=item *
+
+Now provides numeric macros and meaningful C<Exporter> tags.
+
+=item *
+
+No longer uses C<Sys::Hostname> as it may provide useless values in
+unconfigured network environments, so instead uses C<INADDR_LOOPBACK> directly.
+
+=item *
+
+C<syslog()> now uses local timestamp.
+
+=item *
+
+C<setlogmask()> now behaves like its C counterpart.
+
+=item *
+
+C<setlogsock()> will now C<croak()> as documented.
+
+=item *
+
+Improved error and warnings messages.
+
+=item *
+
+Improved documentation.
+
+=back
+
+=item *
+
+C<Term::ANSIColor> upgraded to version 1.10
+
+=over
+
+=item *
+
+Fixes a bug in C<colored> when C<$EACHLINE> is set that caused it to not color
+lines consisting solely of 0 (literal zero).
+
+=item *
+
+Improved tests.
+
+=back
+
+=item *
+
+C<Term::ReadLine> upgraded to version 1.02
+
+=over
+
+=item *
+
+Documentation tweaks
+
+=back
+
+=item *
+
+C<Test::Harness> upgraded to version 2.56 (was 2.48)
+
+=over
+
+=item *
+
+The C<Test::Harness> timer is now off by default.
+
+=item *
+
+Now shows elapsed time in milliseconds.
+
+=item *
+
+Various bug fixes
+
+=back
+
+=item *
+
+C<Test::Simple> upgraded to version 0.62 (was 0.54)
+
+=over
+
+=item *
+
+C<is_deeply()> no longer fails to work for many cases
+
+=item *
+
+Various minor bug fixes
+
+=item *
+
+Documentation enhancements
+
+=back
+
+=item *
+
+C<Text::Tabs> upgraded to version 2005.0824
+
+=over
+
+=item *
+
+Provides a faster implementation of C<expand>
+
+=back
+
+=item *
+
+C<Text::Wrap> upgraded to version 2005.082401
+
+=over
+
+=item *
+
+Adds C<$Text::Wrap::separator2>, which allows you to preserve existing newlines
+but add line-breaks with some other string.
+
+=back
+
+=item *
+
+C<threads> upgraded to version 1.07
+
+=over
+
+=item *
+
+C<threads> will now honour C<no warnings 'threads'>
+
+=item *
+
+A thread's interpreter is now freed after C<< $t->join() >> rather than after
+C<undef $t>, which should fix some C<ithreads> memory leaks. (Fixed by Dave
+Mitchell)
+
+=item *
+
+Some documentation typo fixes.
+
+=back
+
+=item *
+
+C<threads::shared> upgraded to version 0.94
+
+=over
+
+=item *
+
+Documentation changes only
+
+=item *
+
+Note: An improved implementation of C<threads::shared> is available on
+CPAN - this will be merged into 5.8.9 if it proves stable.
+
+=back
+
+=item *
+
+C<Tie::Hash> upgraded to version 1.02
+
+=over
+
+=item *
+
+Documentation typo fixed
+
+=back
+
+=item *
+
+C<Time::HiRes> upgraded to version 1.86 (was 1.66)
+
+=over
+
+=item *
+
+C<clock_nanosleep()> and C<clock()> functions added
+
+=item *
+
+Support for the POSIX C<clock_gettime()> and C<clock_getres()> has been added
+
+=item *
+
+Return C<undef> or an empty list if the C C<gettimeofday()> function fails
+
+=item *
+
+Improved C<nanosleep> detection
+
+=item *
+
+Internal cleanup
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<Unicode::Collate> upgraded to version 0.52
+
+=over
+
+=item *
+
+Now implements UCA Revision 14 (based on Unicode 4.1.0).
+
+=item *
+
+C<Unicode::Collate->new> method no longer overwrites user's C<$_>
+
+=item *
+
+Enhanced documentation
+
+=back
+
+=item *
+
+C<Unicode::UCD> upgraded to version 0.24
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<User::grent> upgraded to version 1.01
+
+=over
+
+=item *
+
+Documentation typo fixed
+
+=back
+
+=item *
+
+C<utf8> upgraded to version 1.06
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<vmsish> upgraded to version 1.02
+
+=over
+
+=item *
+
+Documentation typos fixed
+
+=back
+
+=item *
+
+C<warnings> upgraded to version 1.05
+
+=over
+
+=item *
+
+Gentler messing with C<Carp::> internals
+
+=item *
+
+Internal cleanup
+
+=item *
+
+Documentation update
+
+=back
+
+=item *
+
+C<Win32> upgraded to version 0.2601
+
+=for cynics And how many perl 5.8.x versions can I release ahead of Vista?
+
+=over
+
+=item *
+
+Provides Windows Vista support to C<Win32::GetOSName>
+
+=item *
+
+Documentation enhancements
+
+=back
+
+=item *
+
+C<XS::Typemap> upgraded to version 0.02
+
+=over
+
+=item *
+
+Internal cleanup
+
+=back
+
+=back
+
+=head1 Utility Changes
+
+=head2 C<h2xs> enhancements
+
+C<h2xs> implements new option C<--use-xsloader> to force use of
+C<XSLoader> even in backwards compatible modules.
+
+The handling of authors' names that had apostrophes has been fixed.
+
+Any enums with negative values are now skipped.
+
+=head2 C<perlivp> enhancements
+
+C<perlivp> implements new option C<-a> and will not check for F<*.ph>
+files by default any more. Use the C<-a> option to run I<all> tests.
+
+=head1 New Documentation
+
+The L<perlglossary> manpage is a glossary of terms used in the Perl
+documentation, technical and otherwise, kindly provided by O'Reilly Media,
+inc.
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Weak reference creation is now I<O(1)> rather than I<O(n)>, courtesy of
+Nicholas Clark. Weak reference deletion remains I<O(n)>, but if deletion only
+happens at program exit, it may be skipped completely.
+
+=item *
+
+Salvador Fandiño provided improvements to reduce the memory usage of C<sort>
+and to speed up some cases.
+
+=item *
+
+Jarkko Hietaniemi and Andy Lester worked to mark as much data as possible in
+the C source files as C<static>, to increase the proportion of the executable
+file that the operating system can share between process, and thus reduce
+real memory usage on multi-user systems.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+Parallel makes should work properly now, although there may still be problems
+if C<make test> is instructed to run in parallel.
+
+Building with Borland's compilers on Win32 should work more smoothly. In
+particular Steve Hay has worked to side step many warnings emitted by their
+compilers and at least one C compiler internal error.
+
+C<Configure> will now detect C<clearenv> and C<unsetenv>, thanks to a patch
+from Alan Burlison. It will also probe for C<futimes> and whether C<sprintf>
+correctly returns the length of the formatted string, which will both be used
+in perl 5.8.9.
+
+There are improved hints for next-3.0, vmesa, IX, Darwin, Solaris, Linux,
+DEC/OSF, HP-UX and MPE/iX
+
+Perl extensions on Windows now can be statically built into the Perl DLL,
+thanks to a work by Vadim Konovalov. (This improvement was actually in 5.8.7,
+but was accidentally omitted from L<perl587delta>).
+
+=head1 Selected Bug Fixes
+
+=head2 no warnings 'category' works correctly with -w
+
+Previously when running with warnings enabled globally via C<-w>, selective
+disabling of specific warning categories would actually turn off all warnings.
+This is now fixed; now C<no warnings 'io';> will only turn off warnings in the
+C<io> class. Previously it would erroneously turn off all warnings.
+
+This bug fix may cause some programs to start correctly issuing warnings.
+
+=head2 Remove over-optimisation
+
+Perl 5.8.4 introduced a change so that assignments of C<undef> to a
+scalar, or of an empty list to an array or a hash, were optimised away. As
+this could cause problems when C<goto> jumps were involved, this change
+has been backed out.
+
+=head2 sprintf() fixes
+
+Using the sprintf() function with some formats could lead to a buffer
+overflow in some specific cases. This has been fixed, along with several
+other bugs, notably in bounds checking.
+
+In related fixes, it was possible for badly written code that did not follow
+the documentation of C<Sys::Syslog> to have formatting vulnerabilities.
+C<Sys::Syslog> has been changed to protect people from poor quality third
+party code.
+
+=head2 Debugger and Unicode slowdown
+
+It had been reported that running under perl's debugger when processing
+Unicode data could cause unexpectedly large slowdowns. The most likely cause
+of this was identified and fixed by Nicholas Clark.
+
+=head2 Smaller fixes
+
+=over 4
+
+=item *
+
+C<FindBin> now works better with directories where access rights are more
+restrictive than usual.
+
+=item *
+
+Several memory leaks in ithreads were closed. An improved implementation of
+C<threads::shared> is available on CPAN - this will be merged into 5.8.9 if
+it proves stable.
+
+=item *
+
+Trailing spaces are now trimmed from C<$!> and C<$^E>.
+
+=item *
+
+Operations that require perl to read a process's list of groups, such as reads
+of C<$(> and C<$)>, now dynamically allocate memory rather than using a
+fixed sized array. The fixed size array could cause C stack exhaustion on
+systems configured to use large numbers of groups.
+
+=item *
+
+C<PerlIO::scalar> now works better with non-default C<$/> settings.
+
+=item *
+
+You can now use the C<x> operator to repeat a C<qw//> list. This used
+to raise a syntax error.
+
+=item *
+
+The debugger now traces correctly execution in eval("")uated code that
+contains #line directives.
+
+=item *
+
+The value of the C<open> pragma is no longer ignored for three-argument
+opens.
+
+=item *
+
+The optimisation of C<for (reverse @a)> introduced in perl 5.8.6 could
+misbehave when the array had undefined elements and was used in LVALUE
+context. Dave Mitchell provided a fix.
+
+=item *
+
+Some case insensitive matches between UTF-8 encoded data and 8 bit regexps,
+and vice versa, could give malformed character warnings. These have been
+fixed by Dave Mitchell and Yves Orton.
+
+=item *
+
+C<lcfirst> and C<ucfirst> could corrupt the string for certain cases where
+the length UTF-8 encoding of the string in lower case, upper case or title
+case differed. This was fixed by Nicholas Clark.
+
+=item *
+
+Perl will now use the C library calls C<unsetenv> and C<clearenv> if present
+to delete keys from C<%ENV> and delete C<%ENV> entirely, thanks to a patch
+from Alan Burlison.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=head2 Attempt to set length of freed array
+
+This is a new warning, produced in situations such as this:
+
+ $r = do {my @a; \$#a};
+ $$r = 503;
+
+=head2 Non-string passed as bitmask
+
+This is a new warning, produced when number has been passed as a argument to
+select(), instead of a bitmask.
+
+ # Wrong, will now warn
+ $rin = fileno(STDIN);
+ ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout);
+
+ # Should be
+ $rin = '';
+ vec($rin,fileno(STDIN),1) = 1;
+ ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout);
+
+=head2 Search pattern not terminated or ternary operator parsed as search pattern
+
+This syntax error indicates that the lexer couldn't find the final
+delimiter of a C<?PATTERN?> construct. Mentioning the ternary operator in
+this error message makes it easier to diagnose syntax errors.
+
+=head1 Changed Internals
+
+There has been a fair amount of refactoring of the C<C> source code, partly to
+make it tidier and more maintainable. The resulting object code and the
+C<perl> binary may well be smaller than 5.8.7, in particular due to a change
+contributed by Dave Mitchell which reworked the warnings code to be
+significantly smaller. Apart from being smaller and possibly faster, there
+should be no user-detectable changes.
+
+Andy Lester supplied many improvements to determine which function
+parameters and local variables could actually be declared C<const> to the C
+compiler. Steve Peters provided new C<*_set> macros and reworked the core to
+use these rather than assigning to macros in LVALUE context.
+
+Dave Mitchell improved the lexer debugging output under C<-DT>
+
+Nicholas Clark changed the string buffer allocation so that it is now rounded
+up to the next multiple of 4 (or 8 on platforms with 64 bit pointers). This
+should reduce the number of calls to C<realloc> without actually using any
+extra memory.
+
+The C<HV>'s array of C<HE*>s is now allocated at the correct (minimal) size,
+thanks to another change by Nicholas Clark. Compile with
+C<-DPERL_USE_LARGE_HV_ALLOC> to use the old, sloppier, default.
+
+For XS or embedding debugging purposes, if perl is compiled with
+C<-DDEBUG_LEAKING_SCALARS_FORK_DUMP> in addition to
+C<-DDEBUG_LEAKING_SCALARS> then a child process is C<fork>ed just before
+global destruction, which is used to display the values of any scalars
+found to have leaked at the end of global destruction. Without this, the
+scalars have already been freed sufficiently at the point of detection that
+it is impossible to produce any meaningful dump of their contents. This
+feature was implemented by the indefatigable Nicholas Clark, based on an idea
+by Mike Giroux.
+
+=head1 Platform Specific Problems
+
+The optimiser on HP-UX 11.23 (Itanium 2) is currently partly disabled (scaled
+down to +O1) when using HP C-ANSI-C; the cause of problems at higher
+optimisation levels is still unclear.
+
+There are a handful of remaining test failures on VMS, mostly due to
+test fixes and minor module tweaks with too many dependencies to
+integrate into this release from the development stream, where they have
+all been corrected. The following is a list of expected failures with
+the patch number of the fix where that is known:
+
+ ext/Devel/PPPort/t/ppphtest.t #26913
+ ext/List/Util/t/p_tainted.t #26912
+ lib/ExtUtils/t/PL_FILES.t #26813
+ lib/ExtUtils/t/basic.t #26813
+ t/io/fs.t
+ t/op/cmp.t
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl589delta.pod b/Master/tlpkg/tlperl/lib/pods/perl589delta.pod
new file mode 100644
index 00000000000..2070cc3aa44
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl589delta.pod
@@ -0,0 +1,2336 @@
+=head1 NAME
+
+perl589delta - what is new for perl v5.8.9
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.8 release and
+the 5.8.9 release.
+
+=head1 Notice
+
+The 5.8.9 release will be the last significant release of the 5.8.x
+series. Any future releases of 5.8.x will likely only be to deal with
+security issues, and platform build failures. Hence you should look to
+migrating to 5.10.x, if you have not started already.
+See L</"Known Problems"> for more information.
+
+=head1 Incompatible Changes
+
+A particular construction in the source code of extensions written in C++
+may need changing. See L</"Changed Internals"> for more details. All
+extensions written in C, most written in C++, and all existing compiled
+extensions are unaffected. This was necessary to improve C++ support.
+
+Other than this, there are no changes intentionally incompatible with 5.8.8.
+If any exist, they are bugs and reports are welcome.
+
+=head1 Core Enhancements
+
+=head2 Unicode Character Database 5.1.0.
+
+The copy of the Unicode Character Database included in Perl 5.8 has
+been updated to 5.1.0 from 4.1.0. See
+L<http://www.unicode.org/versions/Unicode5.1.0/#NotableChanges> for the
+notable changes.
+
+=head2 stat and -X on directory handles
+
+It is now possible to call C<stat> and the C<-X> filestat operators on
+directory handles. As both directory and file handles are barewords, there
+can be ambiguities over which was intended. In these situations the file
+handle semantics are preferred. Both also treat C<*FILE{IO}> filehandles
+like C<*FILE> filehandles.
+
+=head2 Source filters in @INC
+
+It's possible to enhance the mechanism of subroutine hooks in @INC by
+adding a source filter on top of the filehandle opened and returned by the
+hook. This feature was planned a long time ago, but wasn't quite working
+until now. See L<perlfunc/require> for details. (Nicholas Clark)
+
+=head2 Exceptions in constant folding
+
+The constant folding routine is now wrapped in an exception handler, and
+if folding throws an exception (such as attempting to evaluate 0/0), perl
+now retains the current optree, rather than aborting the whole program.
+Without this change, programs would not compile if they had expressions that
+happened to generate exceptions, even though those expressions were in code
+that could never be reached at runtime. (Nicholas Clark, Dave Mitchell)
+
+=head2 C<no VERSION>
+
+You can now use C<no> followed by a version number to specify that you
+want to use a version of perl older than the specified one.
+
+=head2 Improved internal UTF-8 caching code
+
+The code that caches calculated UTF-8 byte offsets for character offsets for
+a string has been re-written. Several bugs have been located and eliminated,
+and the code now makes better use of the information it has, so should be
+faster. In particular, it doesn't scan to the end of a string before
+calculating an offset within the string, which should speed up some operations
+on long strings. It is now possible to disable the caching code at run time,
+to verify that it is not the cause of suspected problems.
+
+=head2 Runtime relocatable installations
+
+There is now F<Configure> support for creating a perl tree that is relocatable
+at run time. see L</Relocatable installations>.
+
+=head2 New internal variables
+
+=over 4
+
+=item C<${^CHILD_ERROR_NATIVE}>
+
+This variable gives the native status returned by the last pipe close,
+backtick command, successful call to C<wait> or C<waitpid>, or from the
+C<system> operator. See L<perlvar> for details. (Contributed by Gisle Aas.)
+
+=item C<${^UTF8CACHE}>
+
+This variable controls the state of the internal UTF-8 offset caching code.
+1 for on (the default), 0 for off, -1 to debug the caching code by checking
+all its results against linear scans, and panicing on any discrepancy.
+
+=back
+
+=head2 C<readpipe> is now overridable
+
+The built-in function C<readpipe> is now overridable. Overriding it permits
+also to override its operator counterpart, C<qx//> (also known as C<``>).
+
+=head2 simple exception handling macros
+
+Perl 5.8.9 (and 5.10.0 onwards) now provides a couple of macros to do very
+basic exception handling in XS modules. You can use these macros if you call
+code that may C<croak>, but you need to do some cleanup before giving control
+back to Perl. See L<perlguts/Exception Handling> for more details.
+
+=head2 -D option enhancements
+
+=over
+
+=item *
+
+C<-Dq> suppresses the I<EXECUTING...> message when running under C<-D>
+
+=item *
+
+C<-Dl> logs runops loop entry and exit, and jump level popping.
+
+=item *
+
+C<-Dv> displays the process id as part of the trace output.
+
+=back
+
+=head2 XS-assisted SWASHGET
+
+Some pure-perl code that the regexp engine was using to retrieve Unicode
+properties and transliteration mappings has been reimplemented in XS
+for faster execution.
+(SADAHIRO Tomoyuki)
+
+=head2 Constant subroutines
+
+The interpreter internals now support a far more memory efficient form of
+inlineable constants. Storing a reference to a constant value in a symbol
+table is equivalent to a full typeglob referencing a constant subroutine,
+but using about 400 bytes less memory. This proxy constant subroutine is
+automatically upgraded to a real typeglob with subroutine if necessary.
+The approach taken is analogous to the existing space optimisation for
+subroutine stub declarations, which are stored as plain scalars in place
+of the full typeglob.
+
+However, to aid backwards compatibility of existing code, which (wrongly)
+does not expect anything other than typeglobs in symbol tables, nothing in
+core uses this feature, other than the regression tests.
+
+Stubs for prototyped subroutines have been stored in symbol tables as plain
+strings, and stubs for unprototyped subroutines as the number -1, since 5.005,
+so code which assumes that the core only places typeglobs in symbol tables
+has been making incorrect assumptions for over 10 years.
+
+=head1 New Platforms
+
+Compile support added for:
+
+=over
+
+=item *
+
+DragonFlyBSD
+
+=item *
+
+MidnightBSD
+
+=item *
+
+MirOS BSD
+
+=item *
+
+RISC OS
+
+=item *
+
+Cray XT4/Catamount
+
+=back
+
+=head1 Modules and Pragmata
+
+=head2 New Modules
+
+=over
+
+=item *
+
+C<Module::Pluggable> is a simple framework to create modules that accept
+pluggable sub-modules. The bundled version is 3.8
+
+=item *
+
+C<Module::CoreList> is a hash of hashes that is keyed on perl version as
+indicated in C<$]>. The bundled version is 2.17
+
+=item *
+
+C<Win32API::File> now available in core on Microsoft Windows. The bundled
+version is 0.1001_01
+
+=item *
+
+C<Devel::InnerPackage> finds all the packages defined by a single file. It is
+part of the C<Module::Pluggable> distribution. The bundled version is 0.3
+
+=back
+
+=head2 Updated Modules
+
+=over
+
+=item *
+
+C<attributes> upgraded to version 0.09
+
+=item *
+
+C<AutoLoader> upgraded to version 5.67
+
+=item *
+
+C<AutoSplit> upgraded to 1.06
+
+=item *
+
+C<autouse> upgraded to version 1.06
+
+=item *
+
+C<B> upgraded from 1.09_01 to 1.19
+
+=over
+
+=item *
+
+provides new pad related abstraction macros C<B::NV::COP_SEQ_RANGE_LOW>,
+C<B::NV::COP_SEQ_RANGE_HIGH>, C<B::NV::PARENT_PAD_INDEX>,
+C<B::NV::PARENT_FAKELEX_FLAGS>, which hides the difference in storage in
+5.10.0 and later.
+
+=item *
+
+provides C<B::sub_generation>, which exposes C<PL_sub_generation>
+
+=item *
+
+provides C<B::GV::isGV_with_GP>, which on pre-5.10 perls always returns true.
+
+=item *
+
+New type C<B::HE> added with methods C<VAL>, C<HASH> and C<SVKEY_force>
+
+=item *
+
+The C<B::GVf_IMPORTED_CV> flag is now set correctly when a proxy
+constant subroutine is imported.
+
+=item *
+
+bugs fixed in the handling of C<PMOP>s.
+
+=item *
+
+C<B::BM::PREVIOUS> returns now C<U32>, not C<U16>.
+C<B::CV::START> and C<B:CV::ROOT> return now C<NULL> on an XSUB,
+C<B::CV::XSUB> and C<B::CV::XSUBANY> return 0 on a non-XSUB.
+
+=back
+
+=item *
+
+C<B::C> upgraded to 1.05
+
+=item *
+
+C<B::Concise> upgraded to 0.76
+
+=over
+
+=item *
+
+new option C<-src> causes the rendering of each statement (starting with
+the nextstate OP) to be preceded by the first line of source code that
+generates it.
+
+=item *
+
+new option C<-stash="somepackage">, C<require>s "somepackage", and then renders
+each function defined in its namespace.
+
+=item *
+
+now has documentation of detailed hint symbols.
+
+=back
+
+=item *
+
+C<B::Debug> upgraded to version 1.05
+
+=item *
+
+C<B::Deparse> upgraded to version 0.87
+
+=over 4
+
+=item *
+
+properly deparse C<print readpipe $x, $y>.
+
+=item *
+
+now handles C<''->()>, C<::()>, C<sub :: {}>, I<etc.> correctly [RT #43010].
+All bugs in parsing these kinds of syntax are now fixed:
+
+ perl -MO=Deparse -e '"my %h = "->()'
+ perl -MO=Deparse -e '::->()'
+ perl -MO=Deparse -e 'sub :: {}'
+ perl -MO=Deparse -e 'package a; sub a::b::c {}'
+ perl -MO=Deparse -e 'sub the::main::road {}'
+
+=item *
+
+does B<not> deparse C<$^H{v_string}>, which is automatically set by the
+internals.
+
+=back
+
+=item *
+
+C<B::Lint> upgraded to version 1.11
+
+=item *
+
+C<B::Terse> upgraded to version 1.05
+
+=item *
+
+C<base> upgraded to version 2.13
+
+=over 4
+
+=item *
+
+loading a module via base.pm would mask a global C<$SIG{__DIE__}> in that
+module.
+
+=item *
+
+push all classes at once in C<@ISA>
+
+=back
+
+=item *
+
+C<Benchmark> upgraded to version 1.10
+
+=item *
+
+C<bigint> upgraded to 0.23
+
+=item *
+
+C<bignum> upgraded to 0.23
+
+=item *
+
+C<bigrat> upgraded to 0.23
+
+=item *
+
+C<blib> upgraded to 0.04
+
+=item *
+
+C<Carp> upgraded to version 1.10
+
+The argument backtrace code now shows C<undef> as C<undef>,
+instead of a string I<"undef">.
+
+=item *
+
+C<CGI> upgraded to version 3.42
+
+=item *
+
+C<charnames> upgraded to 1.06
+
+=item *
+
+C<constant> upgraded to version 1.17
+
+=item *
+
+C<CPAN> upgraded to version 1.9301
+
+=item *
+
+C<Cwd> upgraded to version 3.29 with some platform specific
+improvements (including for VMS).
+
+=item *
+
+C<Data::Dumper> upgraded to version 2.121_17
+
+=over
+
+=item *
+
+Fixes hash iterator current position with the pure Perl version [RT #40668]
+
+=item *
+
+Performance enhancements, which will be most evident on platforms where
+repeated calls to C's C<realloc()> are slow, such as Win32.
+
+=back
+
+=item *
+
+C<DB_File> upgraded to version 1.817
+
+=item *
+
+C<DB_Filter> upgraded to version 0.02
+
+=item *
+
+C<Devel::DProf> upgraded to version 20080331.00
+
+=item *
+
+C<Devel::Peek> upgraded to version 1.04
+
+=item *
+
+C<Devel::PPPort> upgraded to version 3.14
+
+=item *
+
+C<diagnostics> upgraded to version 1.16
+
+=item *
+
+C<Digest> upgraded to version 1.15
+
+=item *
+
+C<Digest::MD5> upgraded to version 2.37
+
+=item *
+
+C<DirHandle> upgraded to version 1.02
+
+=over
+
+=item *
+
+now localises C<$.>, C<$@>, C<$!>, C<$^E>, and C<$?> before closing the
+directory handle to suppress leaking any side effects of warnings about it
+already being closed.
+
+=back
+
+=item *
+
+C<DynaLoader> upgraded to version 1.09
+
+C<DynaLoader> can now dynamically load a loadable object from a file with a
+non-default file extension.
+
+=item *
+
+C<Encode> upgraded to version 2.26
+
+C<Encode::Alias> includes a fix for encoding "646" on Solaris (better known as
+ASCII).
+
+=item *
+
+C<English> upgraded to version 1.03
+
+=item *
+
+C<Errno> upgraded to version 1.10
+
+=item *
+
+C<Exporter> upgraded to version 5.63
+
+=item *
+
+C<ExtUtils::Command> upgraded to version 1.15
+
+=item *
+
+C<ExtUtils::Constant> upgraded to version 0.21
+
+=item *
+
+C<ExtUtils::Embed> upgraded to version 1.28
+
+=item *
+
+C<ExtUtils::Install> upgraded to version 1.50_01
+
+=item *
+
+C<ExtUtils::Installed> upgraded to version 1.43
+
+=item *
+
+C<ExtUtils::MakeMaker> upgraded to version 6.48
+
+=over
+
+=item *
+
+support for C<INSTALLSITESCRIPT> and C<INSTALLVENDORSCRIPT>
+configuration.
+
+=back
+
+=item *
+
+C<ExtUtils::Manifest> upgraded to version 1.55
+
+=item *
+
+C<ExtUtils::ParseXS> upgraded to version 2.19
+
+=item *
+
+C<Fatal> upgraded to version 1.06
+
+=over
+
+=item *
+
+allows built-ins in C<CORE::GLOBAL> to be made fatal.
+
+=back
+
+=item *
+
+C<Fcntl> upgraded to version 1.06
+
+=item *
+
+C<fields> upgraded to version 2.12
+
+=item *
+
+C<File::Basename> upgraded to version 2.77
+
+=item *
+
+C<FileCache> upgraded to version 1.07
+
+=item *
+
+C<File::Compare> upgraded to 1.1005
+
+=item *
+
+C<File::Copy> upgraded to 2.13
+
+=over 4
+
+=item *
+
+now uses 3-arg open.
+
+=back
+
+=item *
+
+C<File::DosGlob> upgraded to 1.01
+
+=item *
+
+C<File::Find> upgraded to version 1.13
+
+=item *
+
+C<File::Glob> upgraded to version 1.06
+
+=over
+
+=item *
+
+fixes spurious results with brackets inside braces.
+
+=back
+
+=item *
+
+C<File::Path> upgraded to version 2.07_02
+
+=item *
+
+C<File::Spec> upgraded to version 3.29
+
+=over 4
+
+=item *
+
+improved handling of bad arguments.
+
+=item *
+
+some platform specific improvements (including for VMS and Cygwin), with
+an optimisation on C<abs2rel> when handling both relative arguments.
+
+=back
+
+=item *
+
+C<File::stat> upgraded to version 1.01
+
+=item *
+
+C<File::Temp> upgraded to version 0.20
+
+=item *
+
+C<filetest> upgraded to version 1.02
+
+=item *
+
+C<Filter::Util::Call> upgraded to version 1.07
+
+=item *
+
+C<Filter::Simple> upgraded to version 0.83
+
+=item *
+
+C<FindBin> upgraded to version 1.49
+
+=item *
+
+C<GDBM_File> upgraded to version 1.09
+
+=item *
+
+C<Getopt::Long> upgraded to version 2.37
+
+=item *
+
+C<Getopt::Std> upgraded to version 1.06
+
+=item *
+
+C<Hash::Util> upgraded to version 0.06
+
+=item *
+
+C<if> upgraded to version 0.05
+
+=item *
+
+C<IO> upgraded to version 1.23
+
+Reduced number of calls to C<getpeername> in C<IO::Socket>
+
+=item *
+
+C<IPC::Open> upgraded to version 1.03
+
+=item *
+
+C<IPC::Open3> upgraded to version 1.03
+
+=item *
+
+C<IPC::SysV> upgraded to version 2.00
+
+=item *
+
+C<lib> upgraded to version 0.61
+
+=over
+
+=item *
+
+avoid warning about loading F<.par> files.
+
+=back
+
+=item *
+
+C<libnet> upgraded to version 1.22
+
+=item *
+
+C<List::Util> upgraded to 1.19
+
+=item *
+
+C<Locale::Maketext> upgraded to 1.13
+
+=item *
+
+C<Math::BigFloat> upgraded to version 1.60
+
+=item *
+
+C<Math::BigInt> upgraded to version 1.89
+
+=item *
+
+C<Math::BigRat> upgraded to version 0.22
+
+=over 4
+
+=item *
+
+implements new C<as_float> method.
+
+=back
+
+=item *
+
+C<Math::Complex> upgraded to version 1.54.
+
+=item *
+
+C<Math::Trig> upgraded to version 1.18.
+
+=item *
+
+C<NDBM_File> upgraded to version 1.07
+
+=over
+
+=item *
+
+improve F<g++> handling for systems using GDBM compatibility headers.
+
+=back
+
+=item *
+
+C<Net::Ping> upgraded to version 2.35
+
+=item *
+
+C<NEXT> upgraded to version 0.61
+
+=over
+
+=item *
+
+fix several bugs with C<NEXT> when working with C<AUTOLOAD>, C<eval> block, and
+within overloaded stringification.
+
+=back
+
+=item *
+
+C<ODBM_File> upgraded to 1.07
+
+=item *
+
+C<open> upgraded to 1.06
+
+=item *
+
+C<ops> upgraded to 1.02
+
+=item *
+
+C<PerlIO::encoding> upgraded to version 0.11
+
+=item *
+
+C<PerlIO::scalar> upgraded to version 0.06
+
+=over 4
+
+=item *
+
+[RT #40267] C<PerlIO::scalar> doesn't respect readonly-ness.
+
+=back
+
+=item *
+
+C<PerlIO::via> upgraded to version 0.05
+
+=item *
+
+C<Pod::Html> upgraded to version 1.09
+
+=item *
+
+C<Pod::Parser> upgraded to version 1.35
+
+=item *
+
+C<Pod::Usage> upgraded to version 1.35
+
+=item *
+
+C<POSIX> upgraded to version 1.15
+
+=over
+
+=item *
+
+C<POSIX> constants that duplicate those in C<Fcntl> are now imported from
+C<Fcntl> and re-exported, rather than being duplicated by C<POSIX>
+
+=item *
+
+C<POSIX::remove> can remove empty directories.
+
+=item *
+
+C<POSIX::setlocale> safer to call multiple times.
+
+=item *
+
+C<POSIX::SigRt> added, which provides access to POSIX realtime signal
+functionality on systems that support it.
+
+=back
+
+=item *
+
+C<re> upgraded to version 0.06_01
+
+=item *
+
+C<Safe> upgraded to version 2.16
+
+=item *
+
+C<Scalar::Util> upgraded to 1.19
+
+=item *
+
+C<SDBM_File> upgraded to version 1.06
+
+=item *
+
+C<SelfLoader> upgraded to version 1.17
+
+=item *
+
+C<Shell> upgraded to version 0.72
+
+=item *
+
+C<sigtrap> upgraded to version 1.04
+
+=item *
+
+C<Socket> upgraded to version 1.81
+
+=over
+
+=item *
+
+this fixes an optimistic use of C<gethostbyname>
+
+=back
+
+=item *
+
+C<Storable> upgraded to 2.19
+
+=item *
+
+C<Switch> upgraded to version 2.13
+
+=item *
+
+C<Sys::Syslog> upgraded to version 0.27
+
+=item *
+
+C<Term::ANSIColor> upgraded to version 1.12
+
+=item *
+
+C<Term::Cap> upgraded to version 1.12
+
+=item *
+
+C<Term::ReadLine> upgraded to version 1.03
+
+=item *
+
+C<Test::Builder> upgraded to version 0.80
+
+=item *
+
+C<Test::Harness> upgraded version to 2.64
+
+=over
+
+=item *
+
+this makes it able to handle newlines.
+
+=back
+
+=item *
+
+C<Test::More> upgraded to version 0.80
+
+=item *
+
+C<Test::Simple> upgraded to version 0.80
+
+=item *
+
+C<Text::Balanced> upgraded to version 1.98
+
+=item *
+
+C<Text::ParseWords> upgraded to version 3.27
+
+=item *
+
+C<Text::Soundex> upgraded to version 3.03
+
+=item *
+
+C<Text::Tabs> upgraded to version 2007.1117
+
+=item *
+
+C<Text::Wrap> upgraded to version 2006.1117
+
+=item *
+
+C<Thread> upgraded to version 2.01
+
+=item *
+
+C<Thread::Semaphore> upgraded to version 2.09
+
+=item *
+
+C<Thread::Queue> upgraded to version 2.11
+
+=over
+
+=item *
+
+added capability to add complex structures (e.g., hash of hashes) to queues.
+
+=item *
+
+added capability to dequeue multiple items at once.
+
+=item *
+
+added new methods to inspect and manipulate queues: C<peek>, C<insert> and
+C<extract>
+
+=back
+
+=item *
+
+C<Tie::Handle> upgraded to version 4.2
+
+=item *
+
+C<Tie::Hash> upgraded to version 1.03
+
+=item *
+
+C<Tie::Memoize> upgraded to version 1.1
+
+=over
+
+=item *
+
+C<Tie::Memoize::EXISTS> now correctly caches its results.
+
+=back
+
+=item *
+
+C<Tie::RefHash> upgraded to version 1.38
+
+=item *
+
+C<Tie::Scalar> upgraded to version 1.01
+
+=item *
+
+C<Tie::StdHandle> upgraded to version 4.2
+
+=item *
+
+C<Time::gmtime> upgraded to version 1.03
+
+=item *
+
+C<Time::Local> upgraded to version 1.1901
+
+=item *
+
+C<Time::HiRes> upgraded to version 1.9715 with various build improvements
+(including VMS) and minor platform-specific bug fixes (including
+for HP-UX 11 ia64).
+
+=item *
+
+C<threads> upgraded to 1.71
+
+=over
+
+=item *
+
+new thread state information methods: C<is_running>, C<is_detached>
+and C<is_joinable>. C<list> method enhanced to return running or joinable
+threads.
+
+=item *
+
+new thread signal method: C<kill>
+
+=item *
+
+added capability to specify thread stack size.
+
+=item *
+
+added capability to control thread exiting behavior. Added a new C<exit>
+method.
+
+=back
+
+=item *
+
+C<threads::shared> upgraded to version 1.27
+
+=over
+
+=item *
+
+smaller and faster implementation that eliminates one internal structure and
+the consequent level of indirection.
+
+=item *
+
+user locks are now stored in a safer manner.
+
+=item *
+
+new function C<shared_clone> creates a copy of an object leaving
+shared elements as-is and deep-cloning non-shared elements.
+
+=item *
+
+added new C<is_shared> method.
+
+=back
+
+=item *
+
+C<Unicode::Normalize> upgraded to version 1.02
+
+=item *
+
+C<Unicode::UCD> upgraded to version 0.25
+
+=item *
+
+C<warnings> upgraded to version 1.05_01
+
+=item *
+
+C<Win32> upgraded to version 0.38
+
+=over 4
+
+=item *
+
+added new function C<GetCurrentProcessId> which returns the regular Windows
+process identifier of the current process, even when called from within a fork.
+
+=back
+
+=item *
+
+C<XSLoader> upgraded to version 0.10
+
+=item *
+
+C<XS::APItest> and C<XS::Typemap> are for internal use only and hence
+no longer installed. Many more tests have been added to C<XS::APItest>.
+
+=back
+
+=head1 Utility Changes
+
+=head2 debugger upgraded to version 1.31
+
+=over 4
+
+=item *
+
+Andreas KE<ouml>nig contributed two functions to save and load the debugger
+history.
+
+=item *
+
+C<NEXT::AUTOLOAD> no longer emits warnings under the debugger.
+
+=item *
+
+The debugger should now correctly find tty the device on OS X 10.5 and VMS
+when the program C<fork>s.
+
+=item *
+
+LVALUE subs now work inside the debugger.
+
+=back
+
+=head2 F<perlthanks>
+
+Perl 5.8.9 adds a new utility F<perlthanks>, which is a variant of F<perlbug>,
+but for sending non-bug-reports to the authors and maintainers of Perl.
+Getting nothing but bug reports can become a bit demoralising - we'll see if
+this changes things.
+
+=head2 F<perlbug>
+
+F<perlbug> now checks if you're reporting about a non-core module and suggests
+you report it to the CPAN author instead.
+
+=head2 F<h2xs>
+
+=over
+
+=item *
+
+won't define an empty string as a constant [RT #25366]
+
+=item *
+
+has examples for C<h2xs -X>
+
+=back
+
+=head2 F<h2ph>
+
+=over 4
+
+=item *
+
+now attempts to deal sensibly with the difference in path implications
+between C<""> and C<< E<lt>E<gt> >> quoting in C<#include> statements.
+
+=item *
+
+now generates correct code for C<#if defined A || defined B>
+[RT #39130]
+
+=back
+
+=head1 New Documentation
+
+As usual, the documentation received its share of corrections, clarifications
+and other nitfixes. More C<< X<...> >> tags were added for indexing.
+
+L<perlunitut> is a tutorial written by Juerd Waalboer on Unicode-related
+terminology and how to correctly handle Unicode in Perl scripts.
+
+L<perlunicode> is updated in section user defined properties.
+
+L<perluniintro> has been updated in the example of detecting data that is not
+valid in particular encoding.
+
+L<perlcommunity> provides an overview of the Perl Community along with further
+resources.
+
+L<CORE> documents the pseudo-namespace for Perl's core routines.
+
+=head1 Changes to Existing Documentation
+
+L<perlglossary> adds I<deprecated modules and features> and I<to be dropped modules>.
+
+L<perlhack> has been updated and added resources on smoke testing.
+
+The Perl FAQs (F<perlfaq1>..F<perlfaq9>) have been updated.
+
+L<perlcheat> is updated with better details on C<\w>, C<\d>, and C<\s>.
+
+L<perldebug> is updated with information on how to call the debugger.
+
+L<perldiag> documentation updated with I<subroutine with an ampersand> on the
+argument to C<exists> and C<delete> and also several terminology updates on
+warnings.
+
+L<perlfork> documents the limitation of C<exec> inside pseudo-processes.
+
+L<perlfunc>:
+
+=over
+
+=item *
+
+Documentation is fixed in section C<caller> and C<pop>.
+
+=item *
+
+Function C<alarm> now mentions C<Time::HiRes::ualarm> in preference
+to C<select>.
+
+=item *
+
+Regarding precedence in C<-X>, filetest operators are the same as unary
+operators, but not regarding parsing and parentheses (spotted by Eirik Berg
+Hanssen).
+
+=item *
+
+L<reverse> function documentation received scalar context examples.
+
+=back
+
+L<perllocale> documentation is adjusted for number localization and
+C<POSIX::setlocale> to fix Debian bug #379463.
+
+L<perlmodlib> is updated with C<CPAN::API::HOWTO> and
+C<Sys::Syslog::win32::Win32>
+
+L<perlre> documentation updated to reflect the differences between
+C<[[:xxxxx:]]> and C<\p{IsXxxxx}> matches. Also added section on C</g> and
+C</c> modifiers.
+
+L<perlreguts> describe the internals of the regular expressions engine. It has
+been contributed by Yves Orton.
+
+L<perlrebackslash> describes all perl regular expression backslash and escape
+sequences.
+
+L<perlrecharclass> describes the syntax and use of character classes in
+Perl Regular Expressions.
+
+L<perlrun> is updated to clarify on the hash seed I<PERL_HASH_SEED>. Also more
+information in options C<-x> and C<-u>.
+
+L<perlsub> example is updated to use a lexical variable for C<opendir> syntax.
+
+L<perlvar> fixes confusion about real GID C<$(> and effective GID C<$)>.
+
+Perl thread tutorial example is fixed in section
+L<perlthrtut/Queues: Passing Data Around> and L<perlothrtut>.
+
+L<perlhack> documentation extensively improved by Jarkko Hietaniemi and others.
+
+L<perltoot> provides information on modifying C<@UNIVERSAL::ISA>.
+
+L<perlport> documentation extended to include different C<kill(-9, ...)>
+semantics on Windows. It also clearly states C<dump> is not supported on Win32
+and cygwin.
+
+F<INSTALL> has been updated and modernised.
+
+=head1 Performance Enhancements
+
+=over
+
+=item *
+
+The default since perl 5.000 has been for perl to create an empty scalar
+with every new typeglob. The increased use of lexical variables means that
+most are now unused. Thanks to Nicholas Clark's efforts, Perl can now be
+compiled with C<-DPERL_DONT_CREATE_GVSV> to avoid creating these empty scalars.
+This will significantly decrease the number of scalars allocated for all
+configurations, and the number of scalars that need to be copied for ithread
+creation. Whilst this option is binary compatible with existing perl
+installations, it does change a long-standing assumption about the
+internals, hence it is not enabled by default, as some third party code may
+rely on the old behaviour.
+
+We would recommend testing with this configuration on new deployments of
+perl, particularly for multi-threaded servers, to see whether all third party
+code is compatible with it, as this configuration may give useful performance
+improvements. For existing installations we would not recommend changing to
+this configuration unless thorough testing is performed before deployment.
+
+=item *
+
+C<diagnostics> no longer uses C<$&>, which results in large speedups
+for regexp matching in all code using it.
+
+=item *
+
+Regular expressions classes of a single character are now treated the same as
+if the character had been used as a literal, meaning that code that uses
+char-classes as an escaping mechanism will see a speedup. (Yves Orton)
+
+=item *
+
+Creating anonymous array and hash references (ie. C<[]> and C<{}>) now incurs
+no more overhead than creating an anonymous list or hash. Nicholas Clark
+provided changes with a saving of two ops and one stack push, which was measured
+as a slightly better than 5% improvement for these operations.
+
+=item *
+
+Many calls to C<strlen()> have been eliminated, either because the length was
+already known, or by adopting or enhancing APIs that pass lengths. This has
+been aided by the adoption of a C<my_sprintf()> wrapper, which returns the
+correct C89 value - the length of the formatted string. Previously we could
+not rely on the return value of C<sprintf()>, because on some ancient but
+extant platforms it still returns C<char *>.
+
+=item *
+
+C<index> is now faster if the search string is stored in UTF-8 but only contains
+characters in the Latin-1 range.
+
+=item *
+
+The Unicode swatch cache inside the regexp engine is now used. (the lookup had
+a key mismatch, present since the initial implementation). [RT #42839]
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Relocatable installations
+
+There is now F<Configure> support for creating a relocatable perl tree. If
+you F<Configure> with C<-Duserelocatableinc>, then the paths in C<@INC> (and
+everything else in C<%Config>) can be optionally located via the path of the
+F<perl> executable.
+
+At start time, if any paths in C<@INC> or C<Config> that F<Configure> marked
+as relocatable (by starting them with C<".../">), then they are prefixed the
+directory of C<$^X>. This allows the relocation can be configured on a
+per-directory basis, although the default with C<-Duserelocatableinc> is that
+everything is relocated. The initial install is done to the original configured
+prefix.
+
+=head2 Configuration improvements
+
+F<Configure> is now better at removing temporary files. Tom Callaway
+(from RedHat) also contributed patches that complete the set of flags
+passed to the compiler and the linker, in particular that C<-fPIC> is now
+enabled on Linux. It will also croak when your F</dev/null> isn't a device.
+
+A new configuration variable C<d_pseudofork> has been to F<Configure>, and is
+available as C<$Config{d_pseudofork}> in the C<Config> module. This
+distinguishes real C<fork> support from the pseudofork emulation used on
+Windows platforms.
+
+F<Config.pod> and F<config.sh> are now placed correctly for cross-compilation.
+
+C<$Config{useshrplib}> is now 'true' rather than 'yes' when using a shared perl
+library.
+
+=head2 Compilation improvements
+
+Parallel makes should work properly now, although there may still be problems
+if C<make test> is instructed to run in parallel.
+
+Many compilation warnings have been cleaned up. A very stubborn compiler
+warning in C<S_emulate_eaccess()> was killed after six attempts.
+F<g++> support has been tuned, especially for FreeBSD.
+
+F<mkppport> has been integrated, and all F<ppport.h> files in the core will now
+be autogenerated at build time (and removed during cleanup).
+
+=head2 Installation improvements.
+
+F<installman> now works with C<-Duserelocatableinc> and C<DESTDIR>.
+
+F<installperl> no longer installs:
+
+=over 4
+
+=item *
+
+static library files of statically linked extensions when a shared perl library
+is being used. (They are not needed. See L</Windows> below).
+
+=item *
+
+F<SIGNATURE> and F<PAUSE*.pub> (CPAN files)
+
+=item *
+
+F<NOTES> and F<PATCHING> (ExtUtils files)
+
+=item *
+
+F<perlld> and F<ld2> (Cygwin files)
+
+=back
+
+=head2 Platform Specific Changes
+
+There are improved hints for AIX, Cygwin, DEC/OSF, FreeBSD, HP/UX, Irix 6
+Linux, MachTen, NetBSD, OS/390, QNX, SCO, Solaris, SunOS, System V Release 5.x
+(UnixWare 7, OpenUNIX 8), Ultrix, UMIPS, uts and VOS.
+
+=head3 FreeBSD
+
+=over 4
+
+=item *
+
+Drop C<-std=c89> and C<-ansi> if using C<long long> as the main integral type,
+else in FreeBSD 6.2 (and perhaps other releases), system headers do not
+declare some functions required by perl.
+
+=back
+
+=head3 Solaris
+
+=over 4
+
+=item *
+
+Starting with Solaris 10, we do not want versioned shared libraries, because
+those often indicate a private use only library. These problems could often
+be triggered when L<SUNWbdb> (Berkeley DB) was installed. Hence if Solaris 10
+is detected set C<ignore_versioned_solibs=y>.
+
+=back
+
+=head3 VMS
+
+=over 4
+
+=item *
+
+Allow IEEE math to be deselected on OpenVMS I64 (but it remains the default).
+
+=item *
+
+Record IEEE usage in C<config.h>
+
+=item *
+
+Help older VMS compilers by using C<ccflags> when building C<munchconfig.exe>.
+
+=item *
+
+Don't try to build old C<Thread> extension on VMS when C<-Duseithreads> has
+been chosen.
+
+=item *
+
+Passing a raw string of "NaN" to F<nawk> causes a core dump - so the string
+has been changed to "*NaN*"
+
+=item *
+
+F<t/op/stat.t> tests will now test hard links on VMS if they are supported.
+
+=back
+
+=head3 Windows
+
+=over 4
+
+=item *
+
+When using a shared perl library F<installperl> no longer installs static
+library files, import library files and export library files (of statically
+linked extensions) and empty bootstrap files (of dynamically linked
+extensions). This fixes a problem building PAR-Packer on Win32 with a debug
+build of perl.
+
+=item *
+
+Various improvements to the win32 build process, including support for Visual
+C++ 2005 Express Edition (aka Visual C++ 8.x).
+
+=item *
+
+F<perl.exe> will now have an icon if built with MinGW or Borland.
+
+=item *
+
+Improvements to the perl-static.exe build process.
+
+=item *
+
+Add Win32 makefile option to link all extensions statically.
+
+=item *
+
+The F<WinCE> directory has been merged into the F<Win32> directory.
+
+=item *
+
+C<setlocale> tests have been re-enabled for Windows XP onwards.
+
+=back
+
+=head1 Selected Bug Fixes
+
+=head2 Unicode
+
+Many many bugs related to the internal Unicode implementation (UTF-8) have
+been fixed. In particular, long standing bugs related to returning Unicode
+via C<tie>, overloading or C<$@> are now gone, some of which were never
+reported.
+
+C<unpack> will internally convert the string back from UTF-8 on numeric types.
+This is a compromise between the full consistency now in 5.10, and the current
+behaviour, which is often used as a "feature" on string types.
+
+Using C<:crlf> and C<UTF-16> IO layers together will now work.
+
+Fixed problems with C<split>, Unicode C</\s+/> and C</ \0/>.
+
+Fixed bug RT #40641 - encoding of Unicode characters in regular expressions.
+
+Fixed a bug where using certain patterns in a regexp led to a panic.
+[RT #45337]
+
+Perl no longer segfaults (due to infinite internal recursion) if the locale's
+character is not UTF-8 [RT #41442]:
+
+ use open ':locale';
+ print STDERR "\x{201e}"; # &bdquo;
+
+=head2 PerlIO
+
+Inconsistencies have been fixed in the reference counting PerlIO uses to keep
+track of Unix file descriptors, and the API used by XS code to manage getting
+and releasing C<FILE *>s
+
+=head2 Magic
+
+Several bugs have been fixed in Magic, the internal system used to implement
+features such as C<tie>, tainting and threads sharing.
+
+C<undef @array> on a tied array now correctly calls the C<CLEAR> method.
+
+Some of the bitwise ops were not checking whether their arguments were magical
+before using them. [RT #24816]
+
+Magic is no longer invoked twice by the expression C<\&$x>
+
+A bug with assigning large numbers and tainting has been resolved.
+[RT #40708]
+
+A new entry has been added to the MAGIC vtable - C<svt_local>. This is used
+when copying magic to the new value during C<local>, allowing certain problems
+with localising shared variables to be resolved.
+
+For the implementation details, see L<perlguts/Magic Virtual Tables>.
+
+=head2 Reblessing overloaded objects now works
+
+Internally, perl object-ness is on the referent, not the reference, even
+though methods can only be called via a reference. However, the original
+implementation of overloading stored flags related to overloading on the
+reference, relying on the flags being copied when the reference was copied,
+or set at the creation of a new reference. This manifests in a bug - if you
+rebless an object from a class that has overloading, into one that does not,
+then any other existing references think that they (still) point to an
+overloaded object, choose these C code paths, and then throw errors.
+Analogously, blessing into an overloaded class when other references exist will
+result in them not using overloading.
+
+The implementation has been fixed for 5.10, but this fix changes the semantics
+of flag bits, so is not binary compatible, so can't be applied to 5.8.9.
+However, 5.8.9 has a work-around that implements the same bug fix. If the
+referent has multiple references, then all the other references are located and
+corrected. A full search is avoided whenever possible by scanning lexicals
+outwards from the current subroutine, and the argument stack.
+
+A certain well known Linux vendor applied incomplete versions of this bug fix
+to their F</usr/bin/perl> and then prematurely closed bug reports about
+performance issues without consulting back upstream. This not being enough,
+they then proceeded to ignore the necessary fixes to these unreleased changes
+for 11 months, until massive pressure was applied by their long-suffering
+paying customers, catalysed by the failings being featured on a prominent blog
+and Slashdot.
+
+=head2 C<strict> now propagates correctly into string evals
+
+Under 5.8.8 and earlier:
+
+ $ perl5.8.8 -e 'use strict; eval "use foo bar" or die $@'
+ Can't locate foo.pm in @INC (@INC contains: ... .) at (eval 1) line 2.
+ BEGIN failed--compilation aborted at (eval 1) line 2.
+
+Under 5.8.9 and later:
+
+ $ perl5.8.9 -e 'use strict; eval "use foo bar" or die $@'
+ Bareword "bar" not allowed while "strict subs" in use at (eval 1) line 1.
+
+This may cause problems with programs that parse the error message and rely
+on the buggy behaviour.
+
+=head2 Other fixes
+
+=over
+
+=item *
+
+The tokenizer no longer treats C<=cute> (and other words beginning
+with C<=cut>) as a synonym for C<=cut>.
+
+=item *
+
+Calling C<CORE::require>
+
+C<CORE::require> and C<CORE::do> were always parsed as C<require> and C<do>
+when they were overridden. This is now fixed.
+
+=item *
+
+Stopped memory leak on long F</etc/groups> entries.
+
+=item *
+
+C<while (my $x ...) { ...; redo }> shouldn't C<undef $x>.
+
+In the presence of C<my> in the conditional of a C<while()>, C<until()>,
+or C<for(;;)> loop, we now add an extra scope to the body so that C<redo>
+doesn't C<undef> the lexical.
+
+=item *
+
+The C<encoding> pragma now correctly ignores anything following an C<@>
+character in the C<LC_ALL> and C<LANG> environment variables. [RT # 49646]
+
+=item *
+
+A segfault observed with some F<gcc> 3.3 optimisations is resolved.
+
+=item *
+
+A possible segfault when C<unpack> used in scalar context with C<()> groups
+is resolved. [RT #50256]
+
+=item *
+
+Resolved issue where C<$!> could be changed by a signal handler interrupting
+a C<system> call.
+
+=item *
+
+Fixed bug RT #37886, symbolic deferencing was allowed in the argument of
+C<defined> even under the influence of C<use strict 'refs'>.
+
+=item *
+
+Fixed bug RT #43207, where C<lc>/C<uc> inside C<sort> affected the return
+value.
+
+=item *
+
+Fixed bug RT #45607, where C<*{"BONK"} = \&{"BONK"}> didn't work correctly.
+
+=item *
+
+Fixed bug RT #35878, croaking from a XSUB called via C<goto &xsub> corrupts perl
+internals.
+
+=item *
+
+Fixed bug RT #32539, F<DynaLoader.o> is moved into F<libperl.so> to avoid the
+need to statically link DynaLoader into the stub perl executable. With this
+F<libperl.so> provides everything needed to get a functional embedded perl
+interpreter to run.
+
+=item *
+
+Fix bug RT #36267 so that assigning to a tied hash doesn't change the
+underlying hash.
+
+=item *
+
+Fix bug RT #6006, regexp replaces using large replacement variables
+fail some of the time, I<i.e.> when substitution contains something
+like C<${10}> (note the bracket) instead of just C<$10>.
+
+=item *
+
+Fix bug RT #45053, C<Perl_newCONSTSUB()> is now thread safe.
+
+=back
+
+=head2 Platform Specific Fixes
+
+=head3 Darwin / MacOS X
+
+=over 4
+
+=item *
+
+Various improvements to 64 bit builds.
+
+=item *
+
+Mutex protection added in C<PerlIOStdio_close()> to avoid race conditions.
+Hopefully this fixes failures in the threads tests F<free.t> and F<blocks.t>.
+
+=item *
+
+Added forked terminal support to the debugger, with the ability to update the
+window title.
+
+=back
+
+=head3 OS/2
+
+=over 4
+
+=item *
+
+A build problem with specifying C<USE_MULTI> and C<USE_ITHREADS> but without
+C<USE_IMP_SYS> has been fixed.
+
+=item *
+
+C<OS2::REXX> upgraded to version 1.04
+
+=back
+
+=head3 Tru64
+
+=over 4
+
+=item *
+
+Aligned floating point build policies for F<cc> and F<gcc>.
+
+=back
+
+=head3 RedHat Linux
+
+=over 4
+
+=item *
+
+Revisited a patch from 5.6.1 for RH7.2 for Intel's F<icc> [RT #7916], added an
+additional check for C<$Config{gccversion}>.
+
+=back
+
+=head3 Solaris/i386
+
+=over 4
+
+=item *
+
+Use C<-DPTR_IS_LONG> when using 64 bit integers
+
+=back
+
+=head3 VMS
+
+=over 4
+
+=item *
+
+Fixed C<PerlIO::Scalar> in-memory file record-style reads.
+
+=item *
+
+pipe shutdown at process exit should now be more robust.
+
+=item *
+
+Bugs in VMS exit handling tickled by C<Test::Harness> 2.64 have been fixed.
+
+=item *
+
+Fix C<fcntl()> locking capability test in F<configure.com>.
+
+=item *
+
+Replaced C<shrplib='define'> with C<useshrplib='true'> on VMS.
+
+=back
+
+=head3 Windows
+
+=over 4
+
+=item *
+
+C<File::Find> used to fail when the target directory is a bare drive letter and
+C<no_chdir> is 1 (the default is 0). [RT #41555]
+
+=item *
+
+A build problem with specifying C<USE_MULTI> and C<USE_ITHREADS> but without
+C<USE_IMP_SYS> has been fixed.
+
+=item *
+
+The process id is no longer truncated to 16 bits on some Windows platforms
+( http://bugs.activestate.com/show_bug.cgi?id=72443 )
+
+=item *
+
+Fixed bug RT #54828 in F<perlio.c> where calling C<binmode> on Win32 and Cgywin
+may cause a segmentation fault.
+
+=back
+
+=head2 Smaller fixes
+
+=over 4
+
+=item *
+
+It is now possible to overload C<eq> when using C<nomethod>.
+
+=item *
+
+Various problems using C<overload> with 64 bit integers corrected.
+
+=item *
+
+The reference count of C<PerlIO> file descriptors is now correctly handled.
+
+=item *
+
+On VMS, escaped dots will be preserved when converted to Unix syntax.
+
+=item *
+
+C<keys %+> no longer throws an C<'ambiguous'> warning.
+
+=item *
+
+Using C<#!perl -d> could trigger an assertion, which has been fixed.
+
+=item *
+
+Don't stringify tied code references in C<@INC> when calling C<require>.
+
+=item *
+
+Code references in C<@INC> report the correct file name when C<__FILE__> is
+used.
+
+=item *
+
+Width and precision in sprintf didn't handle characters above 255 correctly.
+[RT #40473]
+
+=item *
+
+List slices with indices out of range now work more consistently.
+[RT #39882]
+
+=item *
+
+A change introduced with perl 5.8.1 broke the parsing of arguments of the form
+C<-foo=bar> with the C<-s> on the <#!> line. This has been fixed. See
+http://bugs.activestate.com/show_bug.cgi?id=43483
+
+=item *
+
+C<tr///> is now threadsafe. Previously it was storing a swash inside its OP,
+rather than in a pad.
+
+=item *
+
+F<pod2html> labels anchors more consistently and handles nested definition
+lists better.
+
+=item *
+
+C<threads> cleanup veto has been extended to include C<perl_free()> and
+C<perl_destruct()>
+
+=item *
+
+On some systems, changes to C<$ENV{TZ}> would not always be
+respected by the underlying calls to C<localtime_r()>. Perl now
+forces the inspection of the environment on these systems.
+
+=item *
+
+The special variable C<$^R> is now more consistently set when executing
+regexps using the C<(?{...})> construct. In particular, it will still
+be set even if backreferences or optional sub-patterns C<(?:...)?> are
+used.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=head2 panic: sv_chop %s
+
+This new fatal error occurs when the C routine C<Perl_sv_chop()> was passed a
+position that is not within the scalar's string buffer. This is caused by
+buggy XS code, and at this point recovery is not possible.
+
+=head2 Maximal count of pending signals (%s) exceeded
+
+This new fatal error occurs when the perl process has to abort due to
+too many pending signals, which is bound to prevent perl from being
+able to handle further incoming signals safely.
+
+=head2 panic: attempt to call %s in %s
+
+This new fatal error occurs when the ACL version file test operator is used
+where it is not available on the current platform. Earlier checks mean that
+it should never be possible to get this.
+
+=head2 FETCHSIZE returned a negative value
+
+New error indicating that a tied array has claimed to have a negative
+number of elements.
+
+=head2 Can't upgrade %s (%d) to %d
+
+Previously the internal error from the SV upgrade code was the less informative
+I<Can't upgrade that kind of scalar>. It now reports the current internal type,
+and the new type requested.
+
+=head2 %s argument is not a HASH or ARRAY element or a subroutine
+
+This error, thrown if an invalid argument is provided to C<exists> now
+correctly includes "or a subroutine". [RT #38955]
+
+=head2 Cannot make the non-overridable builtin %s fatal
+
+This error in C<Fatal> previously did not show the name of the builtin in
+question (now represented by %s above).
+
+=head2 Unrecognized character '%s' in column %d
+
+This error previously did not state the column.
+
+=head2 Offset outside string
+
+This can now also be generated by a C<seek> on a file handle using
+C<PerlIO::scalar>.
+
+=head2 Invalid escape in the specified encoding in regexp; marked by <-- HERE in m/%s/
+
+New error, introduced as part of the fix to RT #40641 to handle encoding
+of Unicode characters in regular expression comments.
+
+=head2 Your machine doesn't support dump/undump.
+
+A more informative fatal error issued when calling C<dump> on Win32 and
+Cygwin. (Given that the purpose of C<dump> is to abort with a core dump,
+and core dumps can't be produced on these platforms, this is more useful than
+silently exiting.)
+
+=head1 Changed Internals
+
+The perl sources can now be compiled with a C++ compiler instead of a C
+compiler. A necessary implementation details is that under C++, the macro
+C<XS> used to define XSUBs now includes an C<extern "C"> definition. A side
+effect of this is that B<C++> code that used the construction
+
+ typedef XS(SwigPerlWrapper);
+
+now needs to be written
+
+ typedef XSPROTO(SwigPerlWrapper);
+
+using the new C<XSPROTO> macro, in order to compile. C extensions are
+unaffected, although C extensions are encouraged to use C<XSPROTO> too.
+This change was present in the 5.10.0 release of perl, so any actively
+maintained code that happened to use this construction should already have
+been adapted. Code that needs changing will fail with a compilation error.
+
+C<set> magic on localizing/assigning to a magic variable will now only
+trigger for I<container magics>, i.e. it will for C<%ENV> or C<%SIG>
+but not for C<$#array>.
+
+The new API macro C<newSVpvs()> can be used in place of constructions such as
+C<newSVpvn("ISA", 3)>. It takes a single string constant, and at C compile
+time determines its length.
+
+The new API function C<Perl_newSV_type()> can be used as a more efficient
+replacement of the common idiom
+
+ sv = newSV(0);
+ sv_upgrade(sv, type);
+
+Similarly C<Perl_newSVpvn_flags()> can be used to combine
+C<Perl_newSVpv()> with C<Perl_sv_2mortal()> or the equivalent
+C<Perl_sv_newmortal()> with C<Perl_sv_setpvn()>
+
+Two new macros C<mPUSHs()> and C<mXPUSHs()> are added, to make it easier to
+push mortal SVs onto the stack. They were then used to fix several bugs where
+values on the stack had not been mortalised.
+
+A C<Perl_signbit()> function was added to test the sign of an C<NV>. It
+maps to the system one when available.
+
+C<Perl_av_reify()>, C<Perl_lex_end()>, C<Perl_mod()>, C<Perl_op_clear()>,
+C<Perl_pop_return()>, C<Perl_qerror()>, C<Perl_setdefout()>,
+C<Perl_vivify_defelem()> and C<Perl_yylex()> are now visible to extensions.
+This was required to allow C<Data::Alias> to work on Windows.
+
+C<Perl_find_runcv()> is now visible to perl core extensions. This was required
+to allow C<Sub::Current> to work on Windows.
+
+C<ptr_table*> functions are now available in unthreaded perl. C<Storable>
+takes advantage of this.
+
+There have been many small cleanups made to the internals. In particular,
+C<Perl_sv_upgrade()> has been simplified considerably, with a straight-through
+code path that uses C<memset()> and C<memcpy()> to initialise the new body,
+rather than assignment via multiple temporary variables. It has also
+benefited from simplification and de-duplication of the arena management
+code.
+
+A lot of small improvements in the code base were made due to reports from
+the Coverity static code analyzer.
+
+Corrected use and documentation of C<Perl_gv_stashpv()>, C<Perl_gv_stashpvn()>,
+C<Perl_gv_stashsv()> functions (last parameter is a bitmask, not boolean).
+
+C<PERL_SYS_INIT>, C<PERL_SYS_INIT3> and C<PERL_SYS_TERM> macros have been
+changed into functions.
+
+C<PERLSYS_TERM> no longer requires a context. C<PerlIO_teardown()>
+is now called without a context, and debugging output in this function has
+been disabled because that required that an interpreter was present, an invalid
+assumption at termination time.
+
+All compile time options which affect binary compatibility have been grouped
+together into a global variable (C<PL_bincompat_options>).
+
+The values of C<PERL_REVISION>, C<PERL_VERSION> and C<PERL_SUBVERSION> are
+now baked into global variables (and hence into any shared perl library).
+Additionally under C<MULTIPLICITY>, the perl executable now records the size of
+the interpreter structure (total, and for this version). Coupled with
+C<PL_bincompat_options> this will allow 5.8.10 (and later), when compiled with a
+shared perl library, to perform sanity checks in C<main()> to verify that the
+shared library is indeed binary compatible.
+
+Symbolic references can now have embedded NULs. The new public function
+C<Perl_get_cvn_flags()> can be used in extensions if you have to handle them.
+
+=head2 Macro cleanups
+
+The core code, and XS code in F<ext> that is not dual-lived on CPAN, no longer
+uses the macros C<PL_na>, C<NEWSV()>, C<Null()>, C<Nullav>, C<Nullcv>,
+C<Nullhv>, C<Nullhv> I<etc>. Their use is discouraged in new code,
+particularly C<PL_na>, which is a small performance hit.
+
+=head1 New Tests
+
+Many modules updated from CPAN incorporate new tests. Some core specific
+tests have been added:
+
+=over 4
+
+=item ext/DynaLoader/t/DynaLoader.t
+
+Tests for the C<DynaLoader> module.
+
+=item t/comp/fold.t
+
+Tests for compile-time constant folding.
+
+=item t/io/pvbm.t
+
+Tests incorporated from 5.10.0 which check that there is no unexpected
+interaction between the internal types C<PVBM> and C<PVGV>.
+
+=item t/lib/proxy_constant_subs.t
+
+Tests for the new form of constant subroutines.
+
+=item t/op/attrhand.t
+
+Tests for C<Attribute::Handlers>.
+
+=item t/op/dbm.t
+
+Tests for C<dbmopen>.
+
+=item t/op/inccode-tie.t
+
+Calls all tests in F<t/op/inccode.t> after first tying C<@INC>.
+
+=item t/op/incfilter.t
+
+Tests for source filters returned from code references in C<@INC>.
+
+=item t/op/kill0.t
+
+Tests for RT #30970.
+
+=item t/op/qrstack.t
+
+Tests for RT #41484.
+
+=item t/op/qr.t
+
+Tests for the C<qr//> construct.
+
+=item t/op/regexp_qr_embed.t
+
+Tests for the C<qr//> construct within another regexp.
+
+=item t/op/regexp_qr.t
+
+Tests for the C<qr//> construct.
+
+=item t/op/rxcode.t
+
+Tests for RT #32840.
+
+=item t/op/studytied.t
+
+Tests for C<study> on tied scalars.
+
+=item t/op/substT.t
+
+Tests for C<subst> run under C<-T> mode.
+
+=item t/op/symbolcache.t
+
+Tests for C<undef> and C<delete> on stash entries that are bound to
+subroutines or methods.
+
+=item t/op/upgrade.t
+
+Tests for C<Perl_sv_upgrade()>.
+
+=item t/mro/package_aliases.t
+
+MRO tests for C<isa> and package aliases.
+
+=item t/pod/twice.t
+
+Tests for calling C<Pod::Parser> twice.
+
+=item t/run/cloexec.t
+
+Tests for inheriting file descriptors across C<exec> (close-on-exec).
+
+=item t/uni/cache.t
+
+Tests for the UTF-8 caching code.
+
+=item t/uni/chr.t
+
+Test that strange encodings do not upset C<Perl_pp_chr()>.
+
+=item t/uni/greek.t
+
+Tests for RT #40641.
+
+=item t/uni/latin2.t
+
+Tests for RT #40641.
+
+=item t/uni/overload.t
+
+Tests for returning Unicode from overloaded values.
+
+=item t/uni/tie.t
+
+Tests for returning Unicode from tied variables.
+
+=back
+
+=head1 Known Problems
+
+There are no known new bugs.
+
+However, programs that rely on bugs that have been fixed will have problems.
+Also, many bug fixes present in 5.10.0 can't be back-ported to the 5.8.x
+branch, because they require changes that are binary incompatible, or because
+the code changes are too large and hence too risky to incorporate.
+
+We have only limited volunteer labour, and the maintenance burden is
+getting increasingly complex. Hence this will be the last significant
+release of the 5.8.x series. Any future releases of 5.8.x will likely
+only be to deal with security issues, and platform build
+failures. Hence you should look to migrating to 5.10.x, if you have
+not started already. Alternatively, if business requirements constrain
+you to continue to use 5.8.x, you may wish to consider commercial
+support from firms such as ActiveState.
+
+=head1 Platform Specific Notes
+
+=head2 Win32
+
+C<readdir()>, C<cwd()>, C<$^X> and C<@INC> now use the alternate (short)
+filename if the long name is outside the current codepage (Jan Dubois).
+
+=head3 Updated Modules
+
+=over 4
+
+=item *
+
+C<Win32> upgraded to version 0.38. Now has a documented 'WinVista' response
+from C<GetOSName> and support for Vista's privilege elevation in C<IsAdminUser>.
+Support for Unicode characters in path names. Improved cygwin and Win64
+compatibility.
+
+=item *
+
+C<Win32API> updated to 0.1001_01
+
+=item *
+
+C<killpg()> support added to C<MSWin32> (Jan Dubois).
+
+=item *
+
+C<File::Spec::Win32> upgraded to version 3.2701
+
+=back
+
+=head2 OS/2
+
+=head3 Updated Modules
+
+=over 4
+
+=item *
+
+C<OS2::Process> upgraded to 1.03
+
+Ilya Zakharevich has added and documented several C<Window*> and C<Clipbrd*>
+functions.
+
+=item *
+
+C<OS2::REXX::DLL>, C<OS2::REXX> updated to version 1.03
+
+=back
+
+=head2 VMS
+
+=head3 Updated Modules
+
+=over 4
+
+=item *
+
+C<DCLsym> upgraded to version 1.03
+
+=item *
+
+C<Stdio> upgraded to version 2.4
+
+=item *
+
+C<VMS::XSSymSet> upgraded to 1.1.
+
+=back
+
+=head1 Obituary
+
+Nick Ing-Simmons, long time Perl hacker, author of the C<Tk> and C<Encode>
+modules, F<perlio.c> in the core, and 5.003_02 pumpking, died of a heart
+attack on 25th September 2006. He will be missed.
+
+=head1 Acknowledgements
+
+Some of the work in this release was funded by a TPF grant.
+
+Steve Hay worked behind the scenes working out the causes of the differences
+between core modules, their CPAN releases, and previous core releases, and
+the best way to rectify them. He doesn't want to do it again. I know this
+feeling, and I'm very glad he did it this time, instead of me.
+
+Paul Fenwick assembled a team of 18 volunteers, who broke the back of writing
+this document. In particular, Bradley Dean, Eddy Tan, and Vincent Pit
+provided half the team's contribution.
+
+Schwern verified the list of updated module versions, correcting quite a few
+errors that I (and everyone else) had missed, both wrongly stated module
+versions, and changed modules that had not been listed.
+
+The crack Berlin-based QA team of Andreas KE<ouml>nig and Slaven Rezic
+tirelessly re-built snapshots, tested most everything CPAN against
+them, and then identified the changes responsible for any module regressions,
+ensuring that several show-stopper bugs were stomped before the first release
+candidate was cut.
+
+The other core committers contributed most of the changes, and applied most
+of the patches sent in by the hundreds of contributors listed in F<AUTHORS>.
+
+And obviously, Larry Wall, without whom we wouldn't have Perl.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org. There may also be
+information at http://www.perl.org, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at http://bugs.perl.org/
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for security
+issues in the Perl core, not for modules independently distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl58delta.pod b/Master/tlpkg/tlperl/lib/pods/perl58delta.pod
new file mode 100644
index 00000000000..f3a86798292
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl58delta.pod
@@ -0,0 +1,3746 @@
+=head1 NAME
+
+perl58delta - what is new for perl v5.8.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.6.0 release and
+the 5.8.0 release.
+
+Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
+maintenance release since the two releases were kept closely
+coordinated (while 5.8.0 was still called 5.7.something).
+
+Changes that were integrated into the 5.6.1 release are marked C<[561]>.
+Many of these changes have been further developed since 5.6.1 was released,
+those are marked C<[561+]>.
+
+You can see the list of changes in the 5.6.1 release (both from the
+5.005_03 release and the 5.6.0 release) by reading L<perl561delta>.
+
+=head1 Highlights In 5.8.0
+
+=over 4
+
+=item *
+
+Better Unicode support
+
+=item *
+
+New IO Implementation
+
+=item *
+
+New Thread Implementation
+
+=item *
+
+Better Numeric Accuracy
+
+=item *
+
+Safe Signals
+
+=item *
+
+Many New Modules
+
+=item *
+
+More Extensive Regression Testing
+
+=back
+
+=head1 Incompatible Changes
+
+=head2 Binary Incompatibility
+
+B<Perl 5.8 is not binary compatible with earlier releases of Perl.>
+
+B<You have to recompile your XS modules.>
+
+(Pure Perl modules should continue to work.)
+
+The major reason for the discontinuity is the new IO architecture
+called PerlIO. PerlIO is the default configuration because without
+it many new features of Perl 5.8 cannot be used. In other words:
+you just have to recompile your modules containing XS code, sorry
+about that.
+
+In future releases of Perl, non-PerlIO aware XS modules may become
+completely unsupported. This shouldn't be too difficult for module
+authors, however: PerlIO has been designed as a drop-in replacement
+(at the source code level) for the stdio interface.
+
+Depending on your platform, there are also other reasons why
+we decided to break binary compatibility, please read on.
+
+=head2 64-bit platforms and malloc
+
+If your pointers are 64 bits wide, the Perl malloc is no longer being
+used because it does not work well with 8-byte pointers. Also,
+usually the system mallocs on such platforms are much better optimized
+for such large memory models than the Perl malloc. Some memory-hungry
+Perl applications like the PDL don't work well with Perl's malloc.
+Finally, other applications than Perl (such as mod_perl) tend to prefer
+the system malloc. Such platforms include Alpha and 64-bit HPPA,
+MIPS, PPC, and Sparc.
+
+=head2 AIX Dynaloading
+
+The AIX dynaloading now uses in AIX releases 4.3 and newer the native
+dlopen interface of AIX instead of the old emulated interface. This
+change will probably break backward compatibility with compiled
+modules. The change was made to make Perl more compliant with other
+applications like mod_perl which are using the AIX native interface.
+
+=head2 Attributes for C<my> variables now handled at run-time
+
+The C<my EXPR : ATTRS> syntax now applies variable attributes at
+run-time. (Subroutine and C<our> variables still get attributes applied
+at compile-time.) See L<attributes> for additional details. In particular,
+however, this allows variable attributes to be useful for C<tie> interfaces,
+which was a deficiency of earlier releases. Note that the new semantics
+doesn't work with the Attribute::Handlers module (as of version 0.76).
+
+=head2 Socket Extension Dynamic in VMS
+
+The Socket extension is now dynamically loaded instead of being
+statically built in. This may or may not be a problem with ancient
+TCP/IP stacks of VMS: we do not know since we weren't able to test
+Perl in such configurations.
+
+=head2 IEEE-format Floating Point Default on OpenVMS Alpha
+
+Perl now uses IEEE format (T_FLOAT) as the default internal floating
+point format on OpenVMS Alpha, potentially breaking binary compatibility
+with external libraries or existing data. G_FLOAT is still available as
+a configuration option. The default on VAX (D_FLOAT) has not changed.
+
+=head2 New Unicode Semantics (no more C<use utf8>, almost)
+
+Previously in Perl 5.6 to use Unicode one would say "use utf8" and
+then the operations (like string concatenation) were Unicode-aware
+in that lexical scope.
+
+This was found to be an inconvenient interface, and in Perl 5.8 the
+Unicode model has completely changed: now the "Unicodeness" is bound
+to the data itself, and for most of the time "use utf8" is not needed
+at all. The only remaining use of "use utf8" is when the Perl script
+itself has been written in the UTF-8 encoding of Unicode. (UTF-8 has
+not been made the default since there are many Perl scripts out there
+that are using various national eight-bit character sets, which would
+be illegal in UTF-8.)
+
+See L<perluniintro> for the explanation of the current model,
+and L<utf8> for the current use of the utf8 pragma.
+
+=head2 New Unicode Properties
+
+Unicode I<scripts> are now supported. Scripts are similar to (and superior
+to) Unicode I<blocks>. The difference between scripts and blocks is that
+scripts are the glyphs used by a language or a group of languages, while
+the blocks are more artificial groupings of (mostly) 256 characters based
+on the Unicode numbering.
+
+In general, scripts are more inclusive, but not universally so. For
+example, while the script C<Latin> includes all the Latin characters and
+their various diacritic-adorned versions, it does not include the various
+punctuation or digits (since they are not solely C<Latin>).
+
+A number of other properties are now supported, including C<\p{L&}>,
+C<\p{Any}> C<\p{Assigned}>, C<\p{Unassigned}>, C<\p{Blank}> [561] and
+C<\p{SpacePerl}> [561] (along with their C<\P{...}> versions, of course).
+See L<perlunicode> for details, and more additions.
+
+The C<In> or C<Is> prefix to names used with the C<\p{...}> and C<\P{...}>
+are now almost always optional. The only exception is that a C<In> prefix
+is required to signify a Unicode block when a block name conflicts with a
+script name. For example, C<\p{Tibetan}> refers to the script, while
+C<\p{InTibetan}> refers to the block. When there is no name conflict, you
+can omit the C<In> from the block name (e.g. C<\p{BraillePatterns}>), but
+to be safe, it's probably best to always use the C<In>).
+
+=head2 REF(...) Instead Of SCALAR(...)
+
+A reference to a reference now stringifies as "REF(0x81485ec)" instead
+of "SCALAR(0x81485ec)" in order to be more consistent with the return
+value of ref().
+
+=head2 pack/unpack D/F recycled
+
+The undocumented pack/unpack template letters D/F have been recycled
+for better use: now they stand for long double (if supported by the
+platform) and NV (Perl internal floating point type). (They used
+to be aliases for d/f, but you never knew that.)
+
+=head2 glob() now returns filenames in alphabetical order
+
+The list of filenames from glob() (or <...>) is now by default sorted
+alphabetically to be csh-compliant (which is what happened before
+in most Unix platforms). (bsd_glob() does still sort platform
+natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) [561]
+
+=head2 Deprecations
+
+=over 4
+
+=item *
+
+The semantics of bless(REF, REF) were unclear and until someone proves
+it to make some sense, it is forbidden.
+
+=item *
+
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
+
+=item *
+
+Using chdir("") or chdir(undef) instead of explicit chdir() is
+doubtful. A failure (think chdir(some_function()) can lead into
+unintended chdir() to the home directory, therefore this behaviour
+is deprecated.
+
+=item *
+
+The builtin dump() function has probably outlived most of its
+usefulness. The core-dumping functionality will remain in future
+available as an explicit call to C<CORE::dump()>, but in future
+releases the behaviour of an unqualified C<dump()> call may change.
+
+=item *
+
+The very dusty examples in the eg/ directory have been removed.
+Suggestions for new shiny examples welcome but the main issue is that
+the examples need to be documented, tested and (most importantly)
+maintained.
+
+=item *
+
+The (bogus) escape sequences \8 and \9 now give an optional warning
+("Unrecognized escape passed through"). There is no need to \-escape
+any C<\w> character.
+
+=item *
+
+The *glob{FILEHANDLE} is deprecated, use *glob{IO} instead.
+
+=item *
+
+The C<package;> syntax (C<package> without an argument) has been
+deprecated. Its semantics were never that clear and its
+implementation even less so. If you have used that feature to
+disallow all but fully qualified variables, C<use strict;> instead.
+
+=item *
+
+The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
+recognised but now cause fatal errors. The previous behaviour of
+ignoring them by default and warning if requested was unacceptable
+since it, in a way, falsely promised that the features could be used.
+
+=item *
+
+In future releases, non-PerlIO aware XS modules may become completely
+unsupported. Since PerlIO is a drop-in replacement for stdio at the
+source code level, this shouldn't be that drastic a change.
+
+=item *
+
+Previous versions of perl and some readings of some sections of Camel
+III implied that the C<:raw> "discipline" was the inverse of C<:crlf>.
+Turning off "clrfness" is no longer enough to make a stream truly
+binary. So the PerlIO C<:raw> layer (or "discipline", to use the Camel
+book's older terminology) is now formally defined as being equivalent
+to binmode(FH) - which is in turn defined as doing whatever is
+necessary to pass each byte as-is without any translation. In
+particular binmode(FH) - and hence C<:raw> - will now turn off both
+CRLF and UTF-8 translation and remove other layers (e.g. :encoding())
+which would modify byte stream.
+
+=item *
+
+The current user-visible implementation of pseudo-hashes (the weird
+use of the first array element) is deprecated starting from Perl 5.8.0
+and will be removed in Perl 5.10.0, and the feature will be
+implemented differently. Not only is the current interface rather
+ugly, but the current implementation slows down normal array and hash
+use quite noticeably. The C<fields> pragma interface will remain
+available. The I<restricted hashes> interface is expected to
+be the replacement interface (see L<Hash::Util>). If your existing
+programs depends on the underlying implementation, consider using
+L<Class::PseudoHash> from CPAN.
+
+=item *
+
+The syntaxes C<< @a->[...] >> and C<< %h->{...} >> have now been deprecated.
+
+=item *
+
+After years of trying, suidperl is considered to be too complex to
+ever be considered truly secure. The suidperl functionality is likely
+to be removed in a future release.
+
+=item *
+
+The 5.005 threads model (module C<Thread>) is deprecated and expected
+to be removed in Perl 5.10. Multithreaded code should be migrated to
+the new ithreads model (see L<threads>, L<threads::shared> and
+L<perlthrtut>).
+
+=item *
+
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+
+=item *
+
+The tr///C and tr///U features have been removed and will not return;
+the interface was a mistake. Sorry about that. For similar
+functionality, see pack('U0', ...) and pack('C0', ...). [561]
+
+=item *
+
+Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
+The prototypes are now checked better at compile-time for invalid
+syntax. An optional warning is generated ("Illegal character in
+prototype...") but this may be upgraded to a fatal error in a future
+release.
+
+=item *
+
+The C<exec LIST> and C<system LIST> operations now produce warnings on
+tainted data and in some future release they will produce fatal errors.
+
+=item *
+
+The existing behaviour when localising tied arrays and hashes is wrong,
+and will be changed in a future release, so do not rely on the existing
+behaviour. See L<"Localising Tied Arrays and Hashes Is Broken">.
+
+=back
+
+=head1 Core Enhancements
+
+=head2 Unicode Overhaul
+
+Unicode in general should be now much more usable than in Perl 5.6.0
+(or even in 5.6.1). Unicode can be used in hash keys, Unicode in
+regular expressions should work now, Unicode in tr/// should work now,
+Unicode in I/O should work now. See L<perluniintro> for introduction
+and L<perlunicode> for details.
+
+=over 4
+
+=item *
+
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.2.0. For more information, see http://www.unicode.org/ .
+[561+] (5.6.1 has UCD 3.0.1.)
+
+=item *
+
+For developers interested in enhancing Perl's Unicode capabilities:
+almost all the UCD files are included with the Perl distribution in
+the F<lib/unicore> subdirectory. The most notable omission, for space
+considerations, is the Unihan database.
+
+=item *
+
+The properties \p{Blank} and \p{SpacePerl} have been added. "Blank" is like
+C isblank(), that is, it contains only "horizontal whitespace" (the space
+character is, the newline isn't), and the "SpacePerl" is the Unicode
+equivalent of C<\s> (\p{Space} isn't, since that includes the vertical
+tabulator character, whereas C<\s> doesn't.)
+
+See "New Unicode Properties" earlier in this document for additional
+information on changes with Unicode properties.
+
+=back
+
+=head2 PerlIO is Now The Default
+
+=over 4
+
+=item *
+
+IO is now by default done via PerlIO rather than system's "stdio".
+PerlIO allows "layers" to be "pushed" onto a file handle to alter the
+handle's behaviour. Layers can be specified at open time via 3-arg
+form of open:
+
+ open($fh,'>:crlf :utf8', $path) || ...
+
+or on already opened handles via extended C<binmode>:
+
+ binmode($fh,':encoding(iso-8859-7)');
+
+The built-in layers are: unix (low level read/write), stdio (as in
+previous Perls), perlio (re-implementation of stdio buffering in a
+portable manner), crlf (does CRLF <=> "\n" translation as on Win32,
+but available on any platform). A mmap layer may be available if
+platform supports it (mostly Unixes).
+
+Layers to be applied by default may be specified via the 'open' pragma.
+
+See L</"Installation and Configuration Improvements"> for the effects
+of PerlIO on your architecture name.
+
+=item *
+
+If your platform supports fork(), you can use the list form of C<open>
+for pipes. For example:
+
+ open KID_PS, "-|", "ps", "aux" or die $!;
+
+forks the ps(1) command (without spawning a shell, as there are more
+than three arguments to open()), and reads its standard output via the
+C<KID_PS> filehandle. See L<perlipc>.
+
+=item *
+
+File handles can be marked as accepting Perl's internal encoding of Unicode
+(UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
+
+ open($fh,">:utf8","Uni.txt");
+
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF-8 what you will be getting but instead
+UTF-EBCDIC. See L<perlunicode>, L<utf8>, and
+http://www.unicode.org/unicode/reports/tr16/ for more information.
+In future releases this naming may change. See L<perluniintro>
+for more information about UTF-8.
+
+=item *
+
+If your environment variables (LC_ALL, LC_CTYPE, LANG) look like you
+want to use UTF-8 (any of the variables match C</utf-?8/i>), your
+STDIN, STDOUT, STDERR handles and the default open layer (see L<open>)
+are marked as UTF-8. (This feature, like other new features that
+combine Unicode and I/O, work only if you are using PerlIO, but that's
+the default.)
+
+Note that after this Perl really does assume that everything is UTF-8:
+for example if some input handle is not, Perl will probably very soon
+complain about the input data like this "Malformed UTF-8 ..." since
+any old eight-bit data is not legal UTF-8.
+
+Note for code authors: if you want to enable your users to use UTF-8
+as their default encoding but in your code still have eight-bit I/O streams
+(such as images or zip files), you need to explicitly open() or binmode()
+with C<:bytes> (see L<perlfunc/open> and L<perlfunc/binmode>), or you
+can just use C<binmode(FH)> (nice for pre-5.8.0 backward compatibility).
+
+=item *
+
+File handles can translate character encodings from/to Perl's internal
+Unicode form on read/write via the ":encoding()" layer.
+
+=item *
+
+File handles can be opened to "in memory" files held in Perl scalars via:
+
+ open($fh,'>', \$variable) || ...
+
+=item *
+
+Anonymous temporary files are available without need to
+'use FileHandle' or other module via
+
+ open($fh,"+>", undef) || ...
+
+That is a literal undef, not an undefined value.
+
+=back
+
+=head2 ithreads
+
+The new interpreter threads ("ithreads" for short) implementation of
+multithreading, by Arthur Bergman, replaces the old "5.005 threads"
+implementation. In the ithreads model any data sharing between
+threads must be explicit, as opposed to the model where data sharing
+was implicit. See L<threads> and L<threads::shared>, and
+L<perlthrtut>.
+
+As a part of the ithreads implementation Perl will also use
+any necessary and detectable reentrant libc interfaces.
+
+=head2 Restricted Hashes
+
+A restricted hash is restricted to a certain set of keys, no keys
+outside the set can be added. Also individual keys can be restricted
+so that the key cannot be deleted and the value cannot be changed.
+No new syntax is involved: the Hash::Util module is the interface.
+
+=head2 Safe Signals
+
+Perl used to be fragile in that signals arriving at inopportune moments
+could corrupt Perl's internal state. Now Perl postpones handling of
+signals until it's safe (between opcodes).
+
+This change may have surprising side effects because signals no longer
+interrupt Perl instantly. Perl will now first finish whatever it was
+doing, like finishing an internal operation (like sort()) or an
+external operation (like an I/O operation), and only then look at any
+arrived signals (and before starting the next operation). No more corrupt
+internal state since the current operation is always finished first,
+but the signal may take more time to get heard. Note that breaking
+out from potentially blocking operations should still work, though.
+
+=head2 Understanding of Numbers
+
+In general a lot of fixing has happened in the area of Perl's
+understanding of numbers, both integer and floating point. Since in
+many systems the standard number parsing functions like C<strtoul()>
+and C<atof()> seem to have bugs, Perl tries to work around their
+deficiencies. This results hopefully in more accurate numbers.
+
+Perl now tries internally to use integer values in numeric conversions
+and basic arithmetics (+ - * /) if the arguments are integers, and
+tries also to keep the results stored internally as integers.
+This change leads to often slightly faster and always less lossy
+arithmetics. (Previously Perl always preferred floating point numbers
+in its math.)
+
+=head2 Arrays now always interpolate into double-quoted strings [561]
+
+In double-quoted strings, arrays now interpolate, no matter what. The
+behavior in earlier versions of perl 5 was that arrays would interpolate
+into strings if the array had been mentioned before the string was
+compiled, and otherwise Perl would raise a fatal compile-time error.
+In versions 5.000 through 5.003, the error was
+
+ Literal @example now requires backslash
+
+In versions 5.004_01 through 5.6.0, the error was
+
+ In string, @example now must be written as \@example
+
+The idea here was to get people into the habit of writing
+C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
+they have always written C<"Give me back my \$5"> when they wanted a
+literal C<$> sign.
+
+Starting with 5.6.1, when Perl now sees an C<@> sign in a
+double-quoted string, it I<always> attempts to interpolate an array,
+regardless of whether or not the array has been used or declared
+already. The fatal error has been downgraded to an optional warning:
+
+ Possible unintended interpolation of @example in string
+
+This warns you that C<"fred@example.com"> is going to turn into
+C<fred.com> if you don't backslash the C<@>.
+See http://perl.plover.com/at-error.html for more details
+about the history here.
+
+=head2 Miscellaneous Changes
+
+=over 4
+
+=item *
+
+AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
+to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+
+=item *
+
+The $Config{byteorder} (and corresponding BYTEORDER in config.h) was
+previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
+was 8. The byteorder was only sizeof(long) bytes long (1234 or 4321),
+but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
+(This problem didn't affect Windows platforms.)
+
+Also, $Config{byteorder} is now computed dynamically--this is more
+robust with "fat binaries" where an executable image contains binaries
+for more than one binary platform, and when cross-compiling.
+
+=item *
+
+C<perl -d:Module=arg,arg,arg> now works (previously one couldn't pass
+in multiple arguments.)
+
+=item *
+
+C<do> followed by a bareword now ensures that this bareword isn't
+a keyword (to avoid a bug where C<do q(foo.pl)> tried to call a
+subroutine called C<q>). This means that for example instead of
+C<do format()> you must write C<do &format()>.
+
+=item *
+
+The builtin dump() now gives an optional warning
+C<dump() better written as CORE::dump()>,
+meaning that by default C<dump(...)> is resolved as the builtin
+dump() which dumps core and aborts, not as (possibly) user-defined
+C<sub dump>. To call the latter, qualify the call as C<&dump(...)>.
+(The whole dump() feature is to considered deprecated, and possibly
+removed/changed in future releases.)
+
+=item *
+
+chomp() and chop() are now overridable. Note, however, that their
+prototype (as given by C<prototype("CORE::chomp")> is undefined,
+because it cannot be expressed and therefore one cannot really write
+replacements to override these builtins.
+
+=item *
+
+END blocks are now run even if you exit/die in a BEGIN block.
+Internally, the execution of END blocks is now controlled by
+PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
+behaviour for Perl embedders. This will default in 5.10. See
+L<perlembed>.
+
+=item *
+
+Formats now support zero-padded decimal fields.
+
+=item *
+
+Although "you shouldn't do that", it was possible to write code that
+depends on Perl's hashed key order (Data::Dumper does this). The new
+algorithm "One-at-a-Time" produces a different hashed key order.
+More details are in L</"Performance Enhancements">.
+
+=item *
+
+lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
+In future releases this may become a fatal error.
+
+=item *
+
+Spurious syntax errors generated in certain situations, when glob()
+caused File::Glob to be loaded for the first time, have been fixed. [561]
+
+=item *
+
+Lvalue subroutines can now return C<undef> in list context. However,
+the lvalue subroutine feature still remains experimental. [561+]
+
+=item *
+
+A lost warning "Can't declare ... dereference in my" has been
+restored (Perl had it earlier but it became lost in later releases.)
+
+=item *
+
+A new special regular expression variable has been introduced:
+C<$^N>, which contains the most-recently closed group (submatch).
+
+=item *
+
+C<no Module;> does not produce an error even if Module does not have an
+unimport() method. This parallels the behavior of C<use> vis-a-vis
+C<import>. [561]
+
+=item *
+
+The numerical comparison operators return C<undef> if either operand
+is a NaN. Previously the behaviour was unspecified.
+
+=item *
+
+C<our> can now have an experimental optional attribute C<unique> that
+affects how global variables are shared among multiple interpreters,
+see L<perlfunc/our>.
+
+=item *
+
+The following builtin functions are now overridable: each(), keys(),
+pop(), push(), shift(), splice(), unshift(). [561]
+
+=item *
+
+C<pack() / unpack()> can now group template letters with C<()> and then
+apply repetition/count modifiers on the groups.
+
+=item *
+
+C<pack() / unpack()> can now process the Perl internal numeric types:
+IVs, UVs, NVs-- and also long doubles, if supported by the platform.
+The template letters are C<j>, C<J>, C<F>, and C<D>.
+
+=item *
+
+C<pack('U0a*', ...)> can now be used to force a string to UTF-8.
+
+=item *
+
+my __PACKAGE__ $obj now works. [561]
+
+=item *
+
+POSIX::sleep() now returns the number of I<unslept> seconds
+(as the POSIX standard says), as opposed to CORE::sleep() which
+returns the number of slept seconds.
+
+=item *
+
+printf() and sprintf() now support parameter reordering using the
+C<%\d+\$> and C<*\d+\$> syntaxes. For example
+
+ printf "%2\$s %1\$s\n", "foo", "bar";
+
+will print "bar foo\n". This feature helps in writing
+internationalised software, and in general when the order
+of the parameters can vary.
+
+=item *
+
+The (\&) prototype now works properly. [561]
+
+=item *
+
+prototype(\[$@%&]) is now available to implicitly create references
+(useful for example if you want to emulate the tie() interface).
+
+=item *
+
+A new command-line option, C<-t> is available. It is the
+little brother of C<-T>: instead of dying on taint violations,
+lexical warnings are given. B<This is only meant as a temporary
+debugging aid while securing the code of old legacy applications.
+This is not a substitute for -T.>
+
+=item *
+
+In other taint news, the C<exec LIST> and C<system LIST> have now been
+considered too risky (think C<exec @ARGV>: it can start any program
+with any arguments), and now the said forms cause a warning under
+lexical warnings. You should carefully launder the arguments to
+guarantee their validity. In future releases of Perl the forms will
+become fatal errors so consider starting laundering now.
+
+=item *
+
+Tied hash interfaces are now required to have the EXISTS and DELETE
+methods (either own or inherited).
+
+=item *
+
+If tr/// is just counting characters, it doesn't attempt to
+modify its target.
+
+=item *
+
+untie() will now call an UNTIE() hook if it exists. See L<perltie>
+for details. [561]
+
+=item *
+
+L<utime> now supports C<utime undef, undef, @files> to change the
+file timestamps to the current time.
+
+=item *
+
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+simply B<between digits>.
+
+=item *
+
+Rather than relying on C's argv[0] (which may not contain a full pathname)
+where possible $^X is now set by asking the operating system.
+(eg by reading F</proc/self/exe> on Linux, F</proc/curproc/file> on FreeBSD)
+
+=item *
+
+A new variable, C<${^TAINT}>, indicates whether taint mode is enabled.
+
+=item *
+
+You can now override the readline() builtin, and this overrides also
+the <FILEHANDLE> angle bracket operator.
+
+=item *
+
+The command-line options -s and -F are now recognized on the shebang
+(#!) line.
+
+=item *
+
+Use of the C</c> match modifier without an accompanying C</g> modifier
+elicits a new warning: C<Use of /c modifier is meaningless without /g>.
+
+Use of C</c> in substitutions, even with C</g>, elicits
+C<Use of /c modifier is meaningless in s///>.
+
+Use of C</g> with C<split> elicits C<Use of /g modifier is meaningless
+in split>.
+
+=item *
+
+Support for the C<CLONE> special subroutine had been added.
+With ithreads, when a new thread is created, all Perl data is cloned,
+however non-Perl data cannot be cloned automatically. In C<CLONE> you
+can do whatever you need to do, like for example handle the cloning of
+non-Perl data, if necessary. C<CLONE> will be executed once for every
+package that has it defined or inherited. It will be called in the
+context of the new thread, so all modifications are made in the new area.
+
+See L<perlmod>
+
+=back
+
+=head1 Modules and Pragmata
+
+=head2 New Modules and Pragmata
+
+=over 4
+
+=item *
+
+C<Attribute::Handlers>, originally by Damian Conway and now maintained
+by Arthur Bergman, allows a class to define attribute handlers.
+
+ package MyPack;
+ use Attribute::Handlers;
+ sub Wolf :ATTR(SCALAR) { print "howl!\n" }
+
+ # later, in some package using or inheriting from MyPack...
+
+ my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
+
+Both variables and routines can have attribute handlers. Handlers can
+be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
+exact compilation phase (BEGIN, CHECK, INIT, or END).
+See L<Attribute::Handlers>.
+
+=item *
+
+C<B::Concise>, by Stephen McCamant, is a new compiler backend for
+walking the Perl syntax tree, printing concise info about ops.
+The output is highly customisable. See L<B::Concise>. [561+]
+
+=item *
+
+The new bignum, bigint, and bigrat pragmas, by Tels, implement
+transparent bignum support (using the Math::BigInt, Math::BigFloat,
+and Math::BigRat backends).
+
+=item *
+
+C<Class::ISA>, by Sean Burke, is a module for reporting the search
+path for a class's ISA tree. See L<Class::ISA>.
+
+=item *
+
+C<Cwd> now has a split personality: if possible, an XS extension is
+used, (this will hopefully be faster, more secure, and more robust)
+but if not possible, the familiar Perl implementation is used.
+
+=item *
+
+C<Devel::PPPort>, originally by Kenneth Albanowski and now
+maintained by Paul Marquess, has been added. It is primarily used
+by C<h2xs> to enhance portability of XS modules between different
+versions of Perl. See L<Devel::PPPort>.
+
+=item *
+
+C<Digest>, frontend module for calculating digests (checksums), from
+Gisle Aas, has been added. See L<Digest>.
+
+=item *
+
+C<Digest::MD5> for calculating MD5 digests (checksums) as defined in
+RFC 1321, from Gisle Aas, has been added. See L<Digest::MD5>.
+
+ use Digest::MD5 'md5_hex';
+
+ $digest = md5_hex("Thirsty Camel");
+
+ print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1
+
+NOTE: the C<MD5> backward compatibility module is deliberately not
+included since its further use is discouraged.
+
+See also L<PerlIO::via::QuotedPrint>.
+
+=item *
+
+C<Encode>, originally by Nick Ing-Simmons and now maintained by Dan
+Kogai, provides a mechanism to translate between different character
+encodings. Support for Unicode, ISO-8859-1, and ASCII are compiled in
+to the module. Several other encodings (like the rest of the
+ISO-8859, CP*/Win*, Mac, KOI8-R, three variants EBCDIC, Chinese,
+Japanese, and Korean encodings) are included and can be loaded at
+runtime. (For space considerations, the largest Chinese encodings
+have been separated into their own CPAN module, Encode::HanExtra,
+which Encode will use if available). See L<Encode>.
+
+Any encoding supported by Encode module is also available to the
+":encoding()" layer if PerlIO is used.
+
+=item *
+
+C<Hash::Util> is the interface to the new I<restricted hashes>
+feature. (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
+Michael Schwern.) See L<Hash::Util>.
+
+=item *
+
+C<I18N::Langinfo> can be used to query locale information.
+See L<I18N::Langinfo>.
+
+=item *
+
+C<I18N::LangTags>, by Sean Burke, has functions for dealing with
+RFC3066-style language tags. See L<I18N::LangTags>.
+
+=item *
+
+C<ExtUtils::Constant>, by Nicholas Clark, is a new tool for extension
+writers for generating XS code to import C header constants.
+See L<ExtUtils::Constant>.
+
+=item *
+
+C<Filter::Simple>, by Damian Conway, is an easy-to-use frontend to
+Filter::Util::Call. See L<Filter::Simple>.
+
+ # in MyFilter.pm:
+
+ package MyFilter;
+
+ use Filter::Simple sub {
+ while (my ($from, $to) = splice @_, 0, 2) {
+ s/$from/$to/g;
+ }
+ };
+
+ 1;
+
+ # in user's code:
+
+ use MyFilter qr/red/ => 'green';
+
+ print "red\n"; # this code is filtered, will print "green\n"
+ print "bored\n"; # this code is filtered, will print "bogreen\n"
+
+ no MyFilter;
+
+ print "red\n"; # this code is not filtered, will print "red\n"
+
+=item *
+
+C<File::Temp>, by Tim Jenness, allows one to create temporary files
+and directories in an easy, portable, and secure way. See L<File::Temp>.
+[561+]
+
+=item *
+
+C<Filter::Util::Call>, by Paul Marquess, provides you with the
+framework to write I<source filters> in Perl. For most uses, the
+frontend Filter::Simple is to be preferred. See L<Filter::Util::Call>.
+
+=item *
+
+C<if>, by Ilya Zakharevich, is a new pragma for conditional inclusion
+of modules.
+
+=item *
+
+L<libnet>, by Graham Barr, is a collection of perl5 modules related
+to network programming. See L<Net::FTP>, L<Net::NNTP>, L<Net::Ping>
+(not part of libnet, but related), L<Net::POP3>, L<Net::SMTP>,
+and L<Net::Time>.
+
+Perl installation leaves libnet unconfigured; use F<libnetcfg>
+to configure it.
+
+=item *
+
+C<List::Util>, by Graham Barr, is a selection of general-utility
+list subroutines, such as sum(), min(), first(), and shuffle().
+See L<List::Util>.
+
+=item *
+
+C<Locale::Constants>, C<Locale::Country>, C<Locale::Currency>
+C<Locale::Language>, and L<Locale::Script>, by Neil Bowers, have
+been added. They provide the codes for various locale standards, such
+as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
+
+ use Locale::Country;
+
+ $country = code2country('jp'); # $country gets 'Japan'
+ $code = country2code('Norway'); # $code gets 'no'
+
+See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>,
+and L<Locale::Language>.
+
+=item *
+
+C<Locale::Maketext>, by Sean Burke, is a localization framework. See
+L<Locale::Maketext>, and L<Locale::Maketext::TPJ13>. The latter is an
+article about software localization, originally published in The Perl
+Journal #13, and republished here with kind permission.
+
+=item *
+
+C<Math::BigRat> for big rational numbers, to accompany Math::BigInt and
+Math::BigFloat, from Tels. See L<Math::BigRat>.
+
+=item *
+
+C<Memoize> can make your functions faster by trading space for time,
+from Mark-Jason Dominus. See L<Memoize>.
+
+=item *
+
+C<MIME::Base64>, by Gisle Aas, allows you to encode data in base64,
+as defined in RFC 2045 - I<MIME (Multipurpose Internet Mail
+Extensions)>.
+
+ use MIME::Base64;
+
+ $encoded = encode_base64('Aladdin:open sesame');
+ $decoded = decode_base64($encoded);
+
+ print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
+
+See L<MIME::Base64>.
+
+=item *
+
+C<MIME::QuotedPrint>, by Gisle Aas, allows you to encode data
+in quoted-printable encoding, as defined in RFC 2045 - I<MIME
+(Multipurpose Internet Mail Extensions)>.
+
+ use MIME::QuotedPrint;
+
+ $encoded = encode_qp("\xDE\xAD\xBE\xEF");
+ $decoded = decode_qp($encoded);
+
+ print $encoded, "\n"; # "=DE=AD=BE=EF\n"
+ print $decoded, "\n"; # "\xDE\xAD\xBE\xEF\n"
+
+See also L<PerlIO::via::QuotedPrint>.
+
+=item *
+
+C<NEXT>, by Damian Conway, is a pseudo-class for method redispatch.
+See L<NEXT>.
+
+=item *
+
+C<open> is a new pragma for setting the default I/O layers
+for open().
+
+=item *
+
+C<PerlIO::scalar>, by Nick Ing-Simmons, provides the implementation
+of IO to "in memory" Perl scalars as discussed above. It also serves
+as an example of a loadable PerlIO layer. Other future possibilities
+include PerlIO::Array and PerlIO::Code. See L<PerlIO::scalar>.
+
+=item *
+
+C<PerlIO::via>, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
+PerlIO layer functionality provided by a class (typically implemented
+in Perl code).
+
+=item *
+
+C<PerlIO::via::QuotedPrint>, by Elizabeth Mattijsen, is an example
+of a C<PerlIO::via> class:
+
+ use PerlIO::via::QuotedPrint;
+ open($fh,">:via(QuotedPrint)",$path);
+
+This will automatically convert everything output to C<$fh> to
+Quoted-Printable. See L<PerlIO::via> and L<PerlIO::via::QuotedPrint>.
+
+=item *
+
+C<Pod::ParseLink>, by Russ Allbery, has been added,
+to parse LZ<><> links in pods as described in the new
+perlpodspec.
+
+=item *
+
+C<Pod::Text::Overstrike>, by Joe Smith, has been added.
+It converts POD data to formatted overstrike text.
+See L<Pod::Text::Overstrike>. [561+]
+
+=item *
+
+C<Scalar::Util> is a selection of general-utility scalar subroutines,
+such as blessed(), reftype(), and tainted(). See L<Scalar::Util>.
+
+=item *
+
+C<sort> is a new pragma for controlling the behaviour of sort().
+
+=item *
+
+C<Storable> gives persistence to Perl data structures by allowing the
+storage and retrieval of Perl data to and from files in a fast and
+compact binary format. Because in effect Storable does serialisation
+of Perl data structures, with it you can also clone deep, hierarchical
+datastructures. Storable was originally created by Raphael Manfredi,
+but it is now maintained by Abhijit Menon-Sen. Storable has been
+enhanced to understand the two new hash features, Unicode keys and
+restricted hashes. See L<Storable>.
+
+=item *
+
+C<Switch>, by Damian Conway, has been added. Just by saying
+
+ use Switch;
+
+you have C<switch> and C<case> available in Perl.
+
+ use Switch;
+
+ switch ($val) {
+
+ case 1 { print "number 1" }
+ case "a" { print "string a" }
+ case [1..10,42] { print "number in list" }
+ case (@array) { print "number in list" }
+ case /\w+/ { print "pattern" }
+ case qr/\w+/ { print "pattern" }
+ case (%hash) { print "entry in hash" }
+ case (\%hash) { print "entry in hash" }
+ case (\&sub) { print "arg to subroutine" }
+ else { print "previous case not true" }
+ }
+
+See L<Switch>.
+
+=item *
+
+C<Test::More>, by Michael Schwern, is yet another framework for writing
+test scripts, more extensive than Test::Simple. See L<Test::More>.
+
+=item *
+
+C<Test::Simple>, by Michael Schwern, has basic utilities for writing
+tests. See L<Test::Simple>.
+
+=item *
+
+C<Text::Balanced>, by Damian Conway, has been added, for extracting
+delimited text sequences from strings.
+
+ use Text::Balanced 'extract_delimited';
+
+ ($a, $b) = extract_delimited("'never say never', he never said", "'", '');
+
+$a will be "'never say never'", $b will be ', he never said'.
+
+In addition to extract_delimited(), there are also extract_bracketed(),
+extract_quotelike(), extract_codeblock(), extract_variable(),
+extract_tagged(), extract_multiple(), gen_delimited_pat(), and
+gen_extract_tagged(). With these, you can implement rather advanced
+parsing algorithms. See L<Text::Balanced>.
+
+=item *
+
+C<threads>, by Arthur Bergman, is an interface to interpreter threads.
+Interpreter threads (ithreads) is the new thread model introduced in
+Perl 5.6 but only available as an internal interface for extension
+writers (and for Win32 Perl for C<fork()> emulation). See L<threads>,
+L<threads::shared>, and L<perlthrtut>.
+
+=item *
+
+C<threads::shared>, by Arthur Bergman, allows data sharing for
+interpreter threads. See L<threads::shared>.
+
+=item *
+
+C<Tie::File>, by Mark-Jason Dominus, associates a Perl array with the
+lines of a file. See L<Tie::File>.
+
+=item *
+
+C<Tie::Memoize>, by Ilya Zakharevich, provides on-demand loaded hashes.
+See L<Tie::Memoize>.
+
+=item *
+
+C<Tie::RefHash::Nestable>, by Edward Avis, allows storing hash
+references (unlike the standard Tie::RefHash) The module is contained
+within Tie::RefHash. See L<Tie::RefHash>.
+
+=item *
+
+C<Time::HiRes>, by Douglas E. Wegscheid, provides high resolution
+timing (ualarm, usleep, and gettimeofday). See L<Time::HiRes>.
+
+=item *
+
+C<Unicode::UCD> offers a querying interface to the Unicode Character
+Database. See L<Unicode::UCD>.
+
+=item *
+
+C<Unicode::Collate>, by SADAHIRO Tomoyuki, implements the UCA
+(Unicode Collation Algorithm) for sorting Unicode strings.
+See L<Unicode::Collate>.
+
+=item *
+
+C<Unicode::Normalize>, by SADAHIRO Tomoyuki, implements the various
+Unicode normalization forms. See L<Unicode::Normalize>.
+
+=item *
+
+C<XS::APItest>, by Tim Jenness, is a test extension that exercises XS
+APIs. Currently only C<printf()> is tested: how to output various
+basic data types from XS.
+
+=item *
+
+C<XS::Typemap>, by Tim Jenness, is a test extension that exercises
+XS typemaps. Nothing gets installed, but the code is worth studying
+for extension writers.
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+=over 4
+
+=item *
+
+The following independently supported modules have been updated to the
+newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
+Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
+(Pod::Man, Pod::Text), Pod::LaTeX [561+], Pod::Parser, Storable,
+Term::ANSIColor, Test, Text-Tabs+Wrap.
+
+=item *
+
+attributes::reftype() now works on tied arguments.
+
+=item *
+
+AutoLoader can now be disabled with C<no AutoLoader;>.
+
+=item *
+
+B::Deparse has been significantly enhanced by Robin Houston. It can
+now deparse almost all of the standard test suite (so that the tests
+still succeed). There is a make target "test.deparse" for trying this
+out.
+
+=item *
+
+Carp now has better interface documentation, and the @CARP_NOT
+interface has been added to get optional control over where errors
+are reported independently of @ISA, by Ben Tilly.
+
+=item *
+
+Class::Struct can now define the classes in compile time.
+
+=item *
+
+Class::Struct now assigns the array/hash element if the accessor
+is called with an array/hash element as the B<sole> argument.
+
+=item *
+
+The return value of Cwd::fastcwd() is now tainted.
+
+=item *
+
+Data::Dumper now has an option to sort hashes.
+
+=item *
+
+Data::Dumper now has an option to dump code references
+using B::Deparse.
+
+=item *
+
+DB_File now supports newer Berkeley DB versions, among
+other improvements.
+
+=item *
+
+Devel::Peek now has an interface for the Perl memory statistics
+(this works only if you are using perl's malloc, and if you have
+compiled with debugging).
+
+=item *
+
+The English module can now be used without the infamous performance
+hit by saying
+
+ use English '-no_match_vars';
+
+(Assuming, of course, that you don't need the troublesome variables
+C<$`>, C<$&>, or C<$'>.) Also, introduced C<@LAST_MATCH_START> and
+C<@LAST_MATCH_END> English aliases for C<@-> and C<@+>.
+
+=item *
+
+ExtUtils::MakeMaker has been significantly cleaned up and fixed.
+The enhanced version has also been backported to earlier releases
+of Perl and submitted to CPAN so that the earlier releases can
+enjoy the fixes.
+
+=item *
+
+The arguments of WriteMakefile() in Makefile.PL are now checked
+for sanity much more carefully than before. This may cause new
+warnings when modules are being installed. See L<ExtUtils::MakeMaker>
+for more details.
+
+=item *
+
+ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
+leads to better portability.
+
+=item *
+
+Fcntl, Socket, and Sys::Syslog have been rewritten by Nicholas Clark
+to use the new-style constant dispatch section (see L<ExtUtils::Constant>).
+This means that they will be more robust and hopefully faster.
+
+=item *
+
+File::Find now chdir()s correctly when chasing symbolic links. [561]
+
+=item *
+
+File::Find now has pre- and post-processing callbacks. It also
+correctly changes directories when chasing symbolic links. Callbacks
+(naughtily) exiting with "next;" instead of "return;" now work.
+
+=item *
+
+File::Find is now (again) reentrant. It also has been made
+more portable.
+
+=item *
+
+The warnings issued by File::Find now belong to their own category.
+You can enable/disable them with C<use/no warnings 'File::Find';>.
+
+=item *
+
+File::Glob::glob() has been renamed to File::Glob::bsd_glob()
+because the name clashes with the builtin glob(). The older
+name is still available for compatibility, but is deprecated. [561]
+
+=item *
+
+File::Glob now supports C<GLOB_LIMIT> constant to limit the size of
+the returned list of filenames.
+
+=item *
+
+IPC::Open3 now allows the use of numeric file descriptors.
+
+=item *
+
+IO::Socket now has an atmark() method, which returns true if the socket
+is positioned at the out-of-band mark. The method is also exportable
+as a sockatmark() function.
+
+=item *
+
+IO::Socket::INET failed to open the specified port if the service name
+was not known. It now correctly uses the supplied port number as is. [561]
+
+=item *
+
+IO::Socket::INET has support for the ReusePort option (if your
+platform supports it). The Reuse option now has an alias, ReuseAddr.
+For clarity, you may want to prefer ReuseAddr.
+
+=item *
+
+IO::Socket::INET now supports a value of zero for C<LocalPort>
+(usually meaning that the operating system will make one up.)
+
+=item *
+
+'use lib' now works identically to @INC. Removing directories
+with 'no lib' now works.
+
+=item *
+
+Math::BigFloat and Math::BigInt have undergone a full rewrite by Tels.
+They are now magnitudes faster, and they support various bignum
+libraries such as GMP and PARI as their backends.
+
+=item *
+
+Math::Complex handles inf, NaN etc., better.
+
+=item *
+
+Net::Ping has been considerably enhanced by Rob Brown: multihoming is
+now supported, Win32 functionality is better, there is now time
+measuring functionality (optionally high-resolution using
+Time::HiRes), and there is now "external" protocol which uses
+Net::Ping::External module which runs your external ping utility and
+parses the output. A version of Net::Ping::External is available in
+CPAN.
+
+Note that some of the Net::Ping tests are disabled when running
+under the Perl distribution since one cannot assume one or more
+of the following: enabled echo port at localhost, full Internet
+connectivity, or sympathetic firewalls. You can set the environment
+variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
+suite to enable all the Net::Ping tests.
+
+=item *
+
+POSIX::sigaction() is now much more flexible and robust.
+You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
+handlers, installing new handlers was not atomic.
+
+=item *
+
+In Safe, C<%INC> is now localised in a Safe compartment so that
+use/require work.
+
+=item *
+
+In SDBM_File on dosish platforms, some keys went missing because of
+lack of support for files with "holes". A workaround for the problem
+has been added.
+
+=item *
+
+In Search::Dict one can now have a pre-processing hook for the
+lines being searched.
+
+=item *
+
+The Shell module now has an OO interface.
+
+=item *
+
+In Sys::Syslog there is now a failover mechanism that will go
+through alternative connection mechanisms until the message
+is successfully logged.
+
+=item *
+
+The Test module has been significantly enhanced.
+
+=item *
+
+Time::Local::timelocal() does not handle fractional seconds anymore.
+The rationale is that neither does localtime(), and timelocal() and
+localtime() are supposed to be inverses of each other.
+
+=item *
+
+The vars pragma now supports declaring fully qualified variables.
+(Something that C<our()> does not and will not support.)
+
+=item *
+
+The C<utf8::> name space (as in the pragma) provides various
+Perl-callable functions to provide low level access to Perl's
+internal Unicode representation. At the moment only length()
+has been implemented.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+Emacs perl mode (emacs/cperl-mode.el) has been updated to version
+4.31.
+
+=item *
+
+F<emacs/e2ctags.pl> is now much faster.
+
+=item *
+
+C<enc2xs> is a tool for people adding their own encodings to the
+Encode module.
+
+=item *
+
+C<h2ph> now supports C trigraphs.
+
+=item *
+
+C<h2xs> now produces a template README.
+
+=item *
+
+C<h2xs> now uses C<Devel::PPPort> for better portability between
+different versions of Perl.
+
+=item *
+
+C<h2xs> uses the new L<ExtUtils::Constant|ExtUtils::Constant> module
+which will affect newly created extensions that define constants.
+Since the new code is more correct (if you have two constants where the
+first one is a prefix of the second one, the first constant B<never>
+got defined), less lossy (it uses integers for integer constant,
+as opposed to the old code that used floating point numbers even for
+integer constants), and slightly faster, you might want to consider
+regenerating your extension code (the new scheme makes regenerating
+easy). L<h2xs> now also supports C trigraphs.
+
+=item *
+
+C<libnetcfg> has been added to configure libnet.
+
+=item *
+
+C<perlbug> is now much more robust. It also sends the bug report to
+perl.org, not perl.com.
+
+=item *
+
+C<perlcc> has been rewritten and its user interface (that is,
+command line) is much more like that of the Unix C compiler, cc.
+(The perlbc tools has been removed. Use C<perlcc -B> instead.)
+B<Note that perlcc is still considered very experimental and
+unsupported.> [561]
+
+=item *
+
+C<perlivp> is a new Installation Verification Procedure utility
+for running any time after installing Perl.
+
+=item *
+
+C<piconv> is an implementation of the character conversion utility
+C<iconv>, demonstrating the new Encode module.
+
+=item *
+
+C<pod2html> now allows specifying a cache directory.
+
+=item *
+
+C<pod2html> now produces XHTML 1.0.
+
+=item *
+
+C<pod2html> now understands POD written using different line endings
+(PC-like CRLF versus Unix-like LF versus MacClassic-like CR).
+
+=item *
+
+C<s2p> has been completely rewritten in Perl. (It is in fact a full
+implementation of sed in Perl: you can use the sed functionality by
+using the C<psed> utility.)
+
+=item *
+
+C<xsubpp> now understands POD documentation embedded in the *.xs
+files. [561]
+
+=item *
+
+C<xsubpp> now supports the OUT keyword.
+
+=back
+
+=head1 New Documentation
+
+=over 4
+
+=item *
+
+perl56delta details the changes between the 5.005 release and the
+5.6.0 release.
+
+=item *
+
+perlclib documents the internal replacements for standard C library
+functions. (Interesting only for extension writers and Perl core
+hackers.) [561+]
+
+=item *
+
+perldebtut is a Perl debugging tutorial. [561+]
+
+=item *
+
+perlebcdic contains considerations for running Perl on EBCDIC
+platforms. [561+]
+
+=item *
+
+perlintro is a gentle introduction to Perl.
+
+=item *
+
+perliol documents the internals of PerlIO with layers.
+
+=item *
+
+perlmodstyle is a style guide for writing modules.
+
+=item *
+
+perlnewmod tells about writing and submitting a new module. [561+]
+
+=item *
+
+perlpacktut is a pack() tutorial.
+
+=item *
+
+perlpod has been rewritten to be clearer and to record the best
+practices gathered over the years.
+
+=item *
+
+perlpodspec is a more formal specification of the pod format,
+mainly of interest for writers of pod applications, not to
+people writing in pod.
+
+=item *
+
+perlretut is a regular expression tutorial. [561+]
+
+=item *
+
+perlrequick is a regular expressions quick-start guide.
+Yes, much quicker than perlretut. [561]
+
+=item *
+
+perltodo has been updated.
+
+=item *
+
+perltootc has been renamed as perltooc (to not to conflict
+with perltoot in filesystems restricted to "8.3" names).
+
+=item *
+
+perluniintro is an introduction to using Unicode in Perl.
+(perlunicode is more of a detailed reference and background
+information)
+
+=item *
+
+perlutil explains the command line utilities packaged with the Perl
+distribution. [561+]
+
+=back
+
+The following platform-specific documents are available before
+the installation as README.I<platform>, and after the installation
+as perlI<platform>:
+
+ perlaix perlamiga perlapollo perlbeos perlbs2000
+ perlce perlcygwin perldgux perldos perlepoc perlfreebsd perlhpux
+ perlhurd perlirix perlmachten perlmacos perlmint perlmpeix
+ perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
+ perltru64 perluts perlvmesa perlvms perlvos perlwin32
+
+These documents usually detail one or more of the following subjects:
+configuring, building, testing, installing, and sometimes also using
+Perl on the said platform.
+
+Eastern Asian Perl users are now welcomed in their own languages:
+README.jp (Japanese), README.ko (Korean), README.cn (simplified
+Chinese) and README.tw (traditional Chinese), which are written in
+normal pod but encoded in EUC-JP, EUC-KR, EUC-CN and Big5. These
+will get installed as
+
+ perljp perlko perlcn perltw
+
+=over 4
+
+=item *
+
+The documentation for the POSIX-BC platform is called "BS2000", to avoid
+confusion with the Perl POSIX module.
+
+=item *
+
+The documentation for the WinCE platform is called perlce (README.ce
+in the source code kit), to avoid confusion with the perlwin32
+documentation on 8.3-restricted filesystems.
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+map() could get pathologically slow when the result list it generates
+is larger than the source list. The performance has been improved for
+common scenarios. [561]
+
+=item *
+
+sort() is also fully reentrant, in the sense that the sort function
+can itself call sort(). This did not work reliably in previous
+releases. [561]
+
+=item *
+
+sort() has been changed to use primarily mergesort internally as
+opposed to the earlier quicksort. For very small lists this may
+result in slightly slower sorting times, but in general the speedup
+should be at least 20%. Additional bonuses are that the worst case
+behaviour of sort() is now better (in computer science terms it now
+runs in time O(N log N), as opposed to quicksort's Theta(N**2)
+worst-case run time behaviour), and that sort() is now stable
+(meaning that elements with identical keys will stay ordered as they
+were before the sort). See the C<sort> pragma for information.
+
+The story in more detail: suppose you want to serve yourself a little
+slice of Pi.
+
+ @digits = ( 3,1,4,1,5,9 );
+
+A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
+Which C<1> comes first is hard to know, since one C<1> looks pretty
+much like any other. You can regard this as totally trivial,
+or somewhat profound. However, if you just want to sort the even
+digits ahead of the odd ones, then what will
+
+ sort { ($a % 2) <=> ($b % 2) } @digits;
+
+yield? The only even digit, C<4>, will come first. But how about
+the odd numbers, which all compare equal? With the quicksort algorithm
+used to implement Perl 5.6 and earlier, the order of ties is left up
+to the sort. So, as you add more and more digits of Pi, the order
+in which the sorted even and odd digits appear will change.
+and, for sufficiently large slices of Pi, the quicksort algorithm
+in Perl 5.8 won't return the same results even if reinvoked with the
+same input. The justification for this rests with quicksort's
+worst case behavior. If you run
+
+ sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
+
+(something you might approximate if you wanted to merge two sorted
+arrays using sort), doubling $N doesn't just double the quicksort time,
+it I<quadruples> it. Quicksort has a worst case run time that can
+grow like N**2, so-called I<quadratic> behaviour, and it can happen
+on patterns that may well arise in normal use. You won't notice this
+for small arrays, but you I<will> notice it with larger arrays,
+and you may not live long enough for the sort to complete on arrays
+of a million elements. So the 5.8 quicksort scrambles large arrays
+before sorting them, as a statistical defence against quadratic behaviour.
+But that means if you sort the same large array twice, ties may be
+broken in different ways.
+
+Because of the unpredictability of tie-breaking order, and the quadratic
+worst-case behaviour, quicksort was I<almost> replaced completely with
+a stable mergesort. I<Stable> means that ties are broken to preserve
+the original order of appearance in the input array. So
+
+ sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
+
+will yield (4,3,1,1,5,9), guaranteed. The even and odd numbers
+appear in the output in the same order they appeared in the input.
+Mergesort has worst case O(N log N) behaviour, the best value
+attainable. And, ironically, this mergesort does particularly
+well where quicksort goes quadratic: mergesort sorts (1..$N, 1..$N)
+in O(N) time. But quicksort was rescued at the last moment because
+it is faster than mergesort on certain inputs and platforms.
+For example, if you really I<don't> care about the order of even
+and odd digits, quicksort will run in O(N) time; it's very good
+at sorting many repetitions of a small number of distinct elements.
+The quicksort divide and conquer strategy works well on platforms
+with relatively small, very fast, caches. Eventually, the problem gets
+whittled down to one that fits in the cache, from which point it
+benefits from the increased memory speed.
+
+Quicksort was rescued by implementing a sort pragma to control aspects
+of the sort. The B<stable> subpragma forces stable behaviour,
+regardless of algorithm. The B<_quicksort> and B<_mergesort>
+subpragmas are heavy-handed ways to select the underlying implementation.
+The leading C<_> is a reminder that these subpragmas may not survive
+beyond 5.8. More appropriate mechanisms for selecting the implementation
+exist, but they wouldn't have arrived in time to save quicksort.
+
+=item *
+
+Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
+( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is
+reasonably fast while producing a much better spread of values than
+the old hashing algorithm (originally by Chris Torek, later tweaked by
+Ilya Zakharevich). Hash values output from the algorithm on a hash of
+all 3-char printable ASCII keys comes much closer to passing the
+DIEHARD random number generation tests. According to perlbench, this
+change has not affected the overall speed of Perl.
+
+=item *
+
+unshift() should now be noticeably faster.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+=head2 Generic Improvements
+
+=over 4
+
+=item *
+
+INSTALL now explains how you can configure Perl to use 64-bit
+integers even on non-64-bit platforms.
+
+=item *
+
+Policy.sh policy change: if you are reusing a Policy.sh file
+(see INSTALL) and you use Configure -Dprefix=/foo/bar and in the old
+Policy $prefix eq $siteprefix and $prefix eq $vendorprefix, all of
+them will now be changed to the new prefix, /foo/bar. (Previously
+only $prefix changed.) If you do not like this new behaviour,
+specify prefix, siteprefix, and vendorprefix explicitly.
+
+=item *
+
+A new optional location for Perl libraries, otherlibdirs, is available.
+It can be used for example for vendor add-ons without disturbing Perl's
+own library directories.
+
+=item *
+
+In many platforms, the vendor-supplied 'cc' is too stripped-down to
+build Perl (basically, 'cc' doesn't do ANSI C). If this seems
+to be the case and 'cc' does not seem to be the GNU C compiler
+'gcc', an automatic attempt is made to find and use 'gcc' instead.
+
+=item *
+
+gcc needs to closely track the operating system release to avoid
+build problems. If Configure finds that gcc was built for a different
+operating system release than is running, it now gives a clearly visible
+warning that there may be trouble ahead.
+
+=item *
+
+Since Perl 5.8 is not binary-compatible with previous releases
+of Perl, Configure no longer suggests including the 5.005
+modules in @INC.
+
+=item *
+
+Configure C<-S> can now run non-interactively. [561]
+
+=item *
+
+Configure support for pdp11-style memory models has been removed due
+to obsolescence. [561]
+
+=item *
+
+configure.gnu now works with options with whitespace in them.
+
+=item *
+
+installperl now outputs everything to STDERR.
+
+=item *
+
+Because PerlIO is now the default on most platforms, "-perlio" doesn't
+get appended to the $Config{archname} (also known as $^O) anymore.
+Instead, if you explicitly choose not to use perlio (Configure command
+line option -Uuseperlio), you will get "-stdio" appended.
+
+=item *
+
+Another change related to the architecture name is that "-64all"
+(-Duse64bitall, or "maximally 64-bit") is appended only if your
+pointers are 64 bits wide. (To be exact, the use64bitall is ignored.)
+
+=item *
+
+In AFS installations, one can configure the root of the AFS to be
+somewhere else than the default F</afs> by using the Configure
+parameter C<-Dafsroot=/some/where/else>.
+
+=item *
+
+APPLLIB_EXP, a lesser-known configuration-time definition, has been
+documented. It can be used to prepend site-specific directories
+to Perl's default search path (@INC); see INSTALL for information.
+
+=item *
+
+The version of Berkeley DB used when the Perl (and, presumably, the
+DB_File extension) was built is now available as
+C<@Config{qw(db_version_major db_version_minor db_version_patch)}>
+from Perl and as C<DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
+DB_VERSION_PATCH_CFG> from C.
+
+=item *
+
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
+
+=item *
+
+If you have CPAN access (either network or a local copy such as a
+CD-ROM) you can during specify extra modules to Configure to build and
+install with Perl using the -Dextras=... option. See INSTALL for
+more details.
+
+=item *
+
+In addition to config.over, a new override file, config.arch, is
+available. This file is supposed to be used by hints file writers
+for architecture-wide changes (as opposed to config.over which is
+for site-wide changes).
+
+=item *
+
+If your file system supports symbolic links, you can build Perl outside
+of the source directory by
+
+ mkdir perl/build/directory
+ cd perl/build/directory
+ sh /path/to/perl/source/Configure -Dmksymlinks ...
+
+This will create in perl/build/directory a tree of symbolic links
+pointing to files in /path/to/perl/source. The original files are left
+unaffected. After Configure has finished, you can just say
+
+ make all test
+
+and Perl will be built and tested, all in perl/build/directory.
+[561]
+
+=item *
+
+For Perl developers, several new make targets for profiling
+and debugging have been added; see L<perlhack>.
+
+=over 8
+
+=item *
+
+Use of the F<gprof> tool to profile Perl has been documented in
+L<perlhack>. There is a make target called "perl.gprof" for
+generating a gprofiled Perl executable.
+
+=item *
+
+If you have GCC 3, there is a make target called "perl.gcov" for
+creating a gcoved Perl executable for coverage analysis. See
+L<perlhack>.
+
+=item *
+
+If you are on IRIX or Tru64 platforms, new profiling/debugging options
+have been added; see L<perlhack> for more information about pixie and
+Third Degree.
+
+=back
+
+=item *
+
+Guidelines of how to construct minimal Perl installations have
+been added to INSTALL.
+
+=item *
+
+The Thread extension is now not built at all under ithreads
+(C<Configure -Duseithreads>) because it wouldn't work anyway (the
+Thread extension requires being Configured with C<-Duse5005threads>).
+
+B<Note that the 5.005 threads are unsupported and deprecated: if you
+have code written for the old threads you should migrate it to the
+new ithreads model.>
+
+=item *
+
+The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
+floating-point numbers is now more picky about using sprintf %.*g
+rules for the conversion. Some platforms that used to use gcvt may
+now resort to the slower sprintf.
+
+=item *
+
+The obsolete method of making a special (e.g., debugging) flavor
+of perl by saying
+
+ make LIBPERL=libperld.a
+
+has been removed. Use -DDEBUGGING instead.
+
+=back
+
+=head2 New Or Improved Platforms
+
+For the list of platforms known to support Perl,
+see L<perlport/"Supported Platforms">.
+
+=over 4
+
+=item *
+
+AIX dynamic loading should be now better supported.
+
+=item *
+
+AIX should now work better with gcc, threads, and 64-bitness. Also the
+long doubles support in AIX should be better now. See L<perlaix>.
+
+=item *
+
+AtheOS ( http://www.atheos.cx/ ) is a new platform.
+
+=item *
+
+BeOS has been reclaimed.
+
+=item *
+
+The DG/UX platform now supports 5.005-style threads.
+See L<perldgux>.
+
+=item *
+
+The DYNIX/ptx platform (also known as dynixptx) is supported at or
+near osvers 4.5.2.
+
+=item *
+
+EBCDIC platforms (z/OS (also known as OS/390), POSIX-BC, and VM/ESA)
+have been regained. Many test suite tests still fail and the
+co-existence of Unicode and EBCDIC isn't quite settled, but the
+situation is much better than with Perl 5.6. See L<perlos390>,
+L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information.
+
+=item *
+
+Building perl with -Duseithreads or -Duse5005threads now works under
+HP-UX 10.20 (previously it only worked under 10.30 or later). You will
+need a thread library package installed. See README.hpux. [561]
+
+=item *
+
+Mac OS Classic is now supported in the mainstream source package
+(MacPerl has of course been available since perl 5.004 but now the
+source code bases of standard Perl and MacPerl have been synchronised)
+[561]
+
+=item *
+
+Mac OS X (or Darwin) should now be able to build Perl even on HFS+
+filesystems. (The case-insensitivity used to confuse the Perl build
+process.)
+
+=item *
+
+NCR MP-RAS is now supported. [561]
+
+=item *
+
+All the NetBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+
+=item *
+
+NetWare from Novell is now supported. See L<perlnetware>.
+
+=item *
+
+NonStop-UX is now supported. [561]
+
+=item *
+
+NEC SUPER-UX is now supported.
+
+=item *
+
+All the OpenBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+
+=item *
+
+Perl has been tested with the GNU pth userlevel thread package
+( http://www.gnu.org/software/pth/pth.html ). All thread tests
+of Perl now work, but not without adding some yield()s to the tests,
+so while pth (and other userlevel thread implementations) can be
+considered to be "working" with Perl ithreads, keep in mind the
+possible non-preemptability of the underlying thread implementation.
+
+=item *
+
+Stratus VOS is now supported using Perl's native build method
+(Configure). This is the recommended method to build Perl on
+VOS. The older methods, which build miniperl, are still
+available. See L<perlvos>. [561+]
+
+=item *
+
+The Amdahl UTS Unix mainframe platform is now supported. [561]
+
+=item *
+
+WinCE is now supported. See L<perlce>.
+
+=item *
+
+z/OS (formerly known as OS/390, formerly known as MVS OE) now has
+support for dynamic loading. This is not selected by default,
+however, you must specify -Dusedl in the arguments of Configure. [561]
+
+=back
+
+=head1 Selected Bug Fixes
+
+Numerous memory leaks and uninitialized memory accesses have been
+hunted down. Most importantly, anonymous subs used to leak quite
+a bit. [561]
+
+=over 4
+
+=item *
+
+The autouse pragma didn't work for Multi::Part::Function::Names.
+
+=item *
+
+caller() could cause core dumps in certain situations. Carp was
+sometimes affected by this problem. In particular, caller() now
+returns a subroutine name of C<(unknown)> for subroutines that have
+been removed from the symbol table.
+
+=item *
+
+chop(@list) in list context returned the characters chopped in
+reverse order. This has been reversed to be in the right order. [561]
+
+=item *
+
+Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
+when building the Perl binary. The only exception to this is SunOS 4.x,
+which needs them. [561]
+
+=item *
+
+The behaviour of non-decimal but numeric string constants such as
+"0x23" was platform-dependent: in some platforms that was seen as 35,
+in some as 0, in some as a floating point number (don't ask). This
+was caused by Perl's using the operating system libraries in a situation
+where the result of the string to number conversion is undefined: now
+Perl consistently handles such strings as zero in numeric contexts.
+
+=item *
+
+Several debugger fixes: exit code now reflects the script exit code,
+condition C<"0"> now treated correctly, the C<d> command now checks
+line number, C<$.> no longer gets corrupted, and all debugger output
+now goes correctly to the socket if RemotePort is set. [561]
+
+=item *
+
+The debugger (perl5db.pl) has been modified to present a more
+consistent commands interface, via (CommandSet=580). perl5db.t was
+also added to test the changes, and as a placeholder for further tests.
+
+See L<perldebug>.
+
+=item *
+
+The debugger has a new C<dumpDepth> option to control the maximum
+depth to which nested structures are dumped. The C<x> command has
+been extended so that C<x N EXPR> dumps out the value of I<EXPR> to a
+depth of at most I<N> levels.
+
+=item *
+
+The debugger can now show lexical variables if you have the CPAN
+module PadWalker installed.
+
+=item *
+
+The order of DESTROYs has been made more predictable.
+
+=item *
+
+Perl 5.6.0 could emit spurious warnings about redefinition of
+dl_error() when statically building extensions into perl.
+This has been corrected. [561]
+
+=item *
+
+L<dprofpp> -R didn't work.
+
+=item *
+
+C<*foo{FORMAT}> now works.
+
+=item *
+
+Infinity is now recognized as a number.
+
+=item *
+
+UNIVERSAL::isa no longer caches methods incorrectly. (This broke
+the Tk extension with 5.6.0.) [561]
+
+=item *
+
+Lexicals I: lexicals outside an eval "" weren't resolved
+correctly inside a subroutine definition inside the eval "" if they
+were not already referenced in the top level of the eval""ed code.
+
+=item *
+
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
+
+=item *
+
+Lexical warnings now propagating correctly between scopes
+and into C<eval "...">.
+
+=item *
+
+C<use warnings qw(FATAL all)> did not work as intended. This has been
+corrected. [561]
+
+=item *
+
+warnings::enabled() now reports the state of $^W correctly if the caller
+isn't using lexical warnings. [561]
+
+=item *
+
+Line renumbering with eval and C<#line> now works. [561]
+
+=item *
+
+Fixed numerous memory leaks, especially in eval "".
+
+=item *
+
+Localised tied variables no longer leak memory
+
+ use Tie::Hash;
+ tie my %tied_hash => 'Tie::StdHash';
+
+ ...
+
+ # Used to leak memory every time local() was called;
+ # in a loop, this added up.
+ local($tied_hash{Foo}) = 1;
+
+=item *
+
+Localised hash elements (and %ENV) are correctly unlocalised to not
+exist, if they didn't before they were localised.
+
+
+ use Tie::Hash;
+ tie my %tied_hash => 'Tie::StdHash';
+
+ ...
+
+ # Nothing has set the FOO element so far
+
+ { local $tied_hash{FOO} = 'Bar' }
+
+ # This used to print, but not now.
+ print "exists!\n" if exists $tied_hash{FOO};
+
+As a side effect of this fix, tied hash interfaces B<must> define
+the EXISTS and DELETE methods.
+
+=item *
+
+mkdir() now ignores trailing slashes in the directory name,
+as mandated by POSIX.
+
+=item *
+
+Some versions of glibc have a broken modfl(). This affects builds
+with C<-Duselongdouble>. This version of Perl detects this brokenness
+and has a workaround for it. The glibc release 2.2.2 is known to have
+fixed the modfl() bug.
+
+=item *
+
+Modulus of unsigned numbers now works (4063328477 % 65535 used to
+return 27406, instead of 27047). [561]
+
+=item *
+
+Some "not a number" warnings introduced in 5.6.0 eliminated to be
+more compatible with 5.005. Infinity is now recognised as a number. [561]
+
+=item *
+
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances. [561]
+
+=item *
+
+Attributes (such as :shared) didn't work with our().
+
+=item *
+
+our() variables will not cause bogus "Variable will not stay shared"
+warnings. [561]
+
+=item *
+
+"our" variables of the same name declared in two sibling blocks
+resulted in bogus warnings about "redeclaration" of the variables.
+The problem has been corrected. [561]
+
+=item *
+
+pack "Z" now correctly terminates the string with "\0".
+
+=item *
+
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused getpwent() to return every other entry.
+
+=item *
+
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options. [561]
+
+=item *
+
+PERL5OPT with embedded spaces didn't work.
+
+=item *
+
+printf() no longer resets the numeric locale to "C".
+
+=item *
+
+C<qw(a\\b)> now parses correctly as C<'a\\b'>: that is, as three
+characters, not four. [561]
+
+=item *
+
+pos() did not return the correct value within s///ge in earlier
+versions. This is now handled correctly. [561]
+
+=item *
+
+Printing quads (64-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
+
+=item *
+
+Regular expressions on references and overloaded scalars now work. [561+]
+
+=item *
+
+Right-hand side magic (GMAGIC) could in many cases such as string
+concatenation be invoked too many times.
+
+=item *
+
+scalar() now forces scalar context even when used in void context.
+
+=item *
+
+SOCKS support is now much more robust.
+
+=item *
+
+sort() arguments are now compiled in the right wantarray context
+(they were accidentally using the context of the sort() itself).
+The comparison block is now run in scalar context, and the arguments
+to be sorted are always provided list context. [561]
+
+=item *
+
+Changed the POSIX character class C<[[:space:]]> to include the (very
+rarely used) vertical tab character. Added a new POSIX-ish character
+class C<[[:blank:]]> which stands for horizontal whitespace
+(currently, the space and the tab).
+
+=item *
+
+The tainting behaviour of sprintf() has been rationalized. It does
+not taint the result of floating point formats anymore, making the
+behaviour consistent with that of string interpolation. [561]
+
+=item *
+
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
+
+=item *
+
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches. These are now handled better. [561]
+
+=item *
+
+Regular expression debug output (whether through C<use re 'debug'>
+or via C<-Dr>) now looks better. [561]
+
+=item *
+
+Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
+bug has been fixed. [561]
+
+=item *
+
+Use of $& could trigger a core dump under some situations. This
+is now avoided. [561]
+
+=item *
+
+The regular expression captured submatches ($1, $2, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them. [561]
+
+=item *
+
+readline() on files opened in "slurp" mode could return an extra
+"" (blank line) at the end in certain situations. This has been
+corrected. [561]
+
+=item *
+
+Autovivification of symbolic references of special variables described
+in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
+again now. [561]
+
+=item *
+
+Sys::Syslog ignored the C<LOG_AUTH> constant.
+
+=item *
+
+$AUTOLOAD, sort(), lock(), and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
+
+=item *
+
+Tie::Array's SPLICE method was broken.
+
+=item *
+
+Allow a read-only string on the left-hand side of a non-modifying tr///.
+
+=item *
+
+If C<STDERR> is tied, warnings caused by C<warn> and C<die> now
+correctly pass to it.
+
+=item *
+
+Several Unicode fixes.
+
+=over 8
+
+=item *
+
+BOMs (byte order marks) at the beginning of Perl files
+(scripts, modules) should now be transparently skipped.
+UTF-16 and UCS-2 encoded Perl files should now be read correctly.
+
+=item *
+
+The character tables have been updated to Unicode 3.2.0.
+
+=item *
+
+Comparing with utf8 data does not magically upgrade non-utf8 data
+into utf8. (This was a problem for example if you were mixing data
+from I/O and Unicode data: your output might have got magically encoded
+as UTF-8.)
+
+=item *
+
+Generating illegal Unicode code points such as U+FFFE, or the UTF-16
+surrogates, now also generates an optional warning.
+
+=item *
+
+C<IsAlnum>, C<IsAlpha>, and C<IsWord> now match titlecase.
+
+=item *
+
+Concatenation with the C<.> operator or via variable interpolation,
+C<eq>, C<substr>, C<reverse>, C<quotemeta>, the C<x> operator,
+substitution with C<s///>, single-quoted UTF-8, should now work.
+
+=item *
+
+The C<tr///> operator now works. Note that the C<tr///CU>
+functionality has been removed (but see pack('U0', ...)).
+
+=item *
+
+C<eval "v200"> now works.
+
+=item *
+
+Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected. [561]
+
+=item *
+
+Zero entries were missing from the Unicode classes such as C<IsDigit>.
+
+=back
+
+=item *
+
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations. [561]
+
+=item *
+
+The Perl parser has been stress tested using both random input and
+Markov chain input and the few found crashes and lockups have been
+fixed.
+
+=back
+
+=head2 Platform Specific Changes and Fixes
+
+=over 4
+
+=item *
+
+BSDI 4.*
+
+Perl now works on post-4.0 BSD/OSes.
+
+=item *
+
+All BSDs
+
+Setting C<$0> now works (as much as possible; see L<perlvar> for details).
+
+=item *
+
+Cygwin
+
+Numerous updates; currently synchronised with Cygwin 1.3.10.
+
+=item *
+
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+
+=item *
+
+EPOC
+
+EPOC now better supported. See README.epoc. [561]
+
+=item *
+
+FreeBSD 3.*
+
+Perl now works on post-3.0 FreeBSDs.
+
+=item *
+
+HP-UX
+
+README.hpux updated; C<Configure -Duse64bitall> now works;
+now uses HP-UX malloc instead of Perl malloc.
+
+=item *
+
+IRIX
+
+Numerous compilation flag and hint enhancements; accidental mixing
+of 32-bit and 64-bit libraries (a doomed attempt) made much harder.
+
+=item *
+
+Linux
+
+=over 8
+
+=item *
+
+Long doubles should now work (see INSTALL). [561]
+
+=item *
+
+Linux previously had problems related to sockaddrlen when using
+accept(), recvfrom() (in Perl: recv()), getpeername(), and
+getsockname().
+
+=back
+
+=item *
+
+Mac OS Classic
+
+Compilation of the standard Perl distribution in Mac OS Classic should
+now work if you have the Metrowerks development environment and the
+missing Mac-specific toolkit bits. Contact the macperl mailing list
+for details.
+
+=item *
+
+MPE/iX
+
+MPE/iX update after Perl 5.6.0. See README.mpeix. [561]
+
+=item *
+
+NetBSD/threads: try installing the GNU pth (should be in the
+packages collection, or http://www.gnu.org/software/pth/),
+and Configure with -Duseithreads.
+
+=item *
+
+NetBSD/sparc
+
+Perl now works on NetBSD/sparc.
+
+=item *
+
+OS/2
+
+Now works with usethreads (see INSTALL). [561]
+
+=item *
+
+Solaris
+
+64-bitness using the Sun Workshop compiler now works.
+
+=item *
+
+Stratus VOS
+
+The native build method requires at least VOS Release 14.5.0
+and GNU C++/GNU Tools 2.0.1 or later. The Perl pack function
+now maps overflowed values to +infinity and underflowed values
+to -infinity.
+
+=item *
+
+Tru64 (aka Digital UNIX, aka DEC OSF/1)
+
+The operating system version letter now recorded in $Config{osvers}.
+Allow compiling with gcc (previously explicitly forbidden). Compiling
+with gcc still not recommended because buggy code results, even with
+gcc 2.95.2.
+
+=item *
+
+Unicos
+
+Fixed various alignment problems that lead into core dumps either
+during build or later; no longer dies on math errors at runtime;
+now using full quad integers (64 bits), previously was using
+only 46 bit integers for speed.
+
+=item *
+
+VMS
+
+See L</"Socket Extension Dynamic in VMS"> and L</"IEEE-format Floating Point
+Default on OpenVMS Alpha"> for important changes not otherwise listed here.
+
+chdir() now works better despite a CRT bug; now works with MULTIPLICITY
+(see INSTALL); now works with Perl's malloc.
+
+The tainting of C<%ENV> elements via C<keys> or C<values> was previously
+unimplemented. It now works as documented.
+
+The C<waitpid> emulation has been improved. The worst bug (now fixed)
+was that a pid of -1 would cause a wildcard search of all processes on
+the system.
+
+POSIX-style signals are now emulated much better on VMS versions prior
+to 7.0.
+
+The C<system> function and backticks operator have improved
+functionality and better error handling. [561]
+
+File access tests now use current process privileges rather than the
+user's default privileges, which could sometimes result in a mismatch
+between reported access and actual access. This improvement is only
+available on VMS v6.0 and later.
+
+There is a new C<kill> implementation based on C<sys$sigprc> that allows
+older VMS systems (pre-7.0) to use C<kill> to send signals rather than
+simply force exit. This implementation also allows later systems to
+call C<kill> from within a signal handler.
+
+Iterative logical name translations are now limited to 10 iterations in
+imitation of SHOW LOGICAL and other OpenVMS facilities.
+
+=item *
+
+Windows
+
+=over 8
+
+=item *
+
+Signal handling now works better than it used to. It is now implemented
+using a Windows message loop, and is therefore less prone to random
+crashes.
+
+=item *
+
+fork() emulation is now more robust, but still continues to have a few
+esoteric bugs and caveats. See L<perlfork> for details. [561+]
+
+=item *
+
+A failed (pseudo)fork now returns undef and sets errno to EAGAIN. [561]
+
+=item *
+
+The following modules now work on Windows:
+
+ ExtUtils::Embed [561]
+ IO::Pipe
+ IO::Poll
+ Net::Ping
+
+=item *
+
+IO::File::new_tmpfile() is no longer limited to 32767 invocations
+per-process.
+
+=item *
+
+Better chdir() return value for a non-existent directory.
+
+=item *
+
+Compiling perl using the 64-bit Platform SDK tools is now supported.
+
+=item *
+
+The Win32::SetChildShowWindow() builtin can be used to control the
+visibility of windows created by child processes. See L<Win32> for
+details.
+
+=item *
+
+Non-blocking waits for child processes (or pseudo-processes) are
+supported via C<waitpid($pid, &POSIX::WNOHANG)>.
+
+=item *
+
+The behavior of system() with multiple arguments has been rationalized.
+Each unquoted argument will be automatically quoted to protect whitespace,
+and any existing whitespace in the arguments will be preserved. This
+improves the portability of system(@args) by avoiding the need for
+Windows C<cmd> shell specific quoting in perl programs.
+
+Note that this means that some scripts that may have relied on earlier
+buggy behavior may no longer work correctly. For example,
+C<system("nmake /nologo", @args)> will now attempt to run the file
+C<nmake /nologo> and will fail when such a file isn't found.
+On the other hand, perl will now execute code such as
+C<system("c:/Program Files/MyApp/foo.exe", @args)> correctly.
+
+=item *
+
+The perl header files no longer suppress common warnings from the
+Microsoft Visual C++ compiler. This means that additional warnings may
+now show up when compiling XS code.
+
+=item *
+
+Borland C++ v5.5 is now a supported compiler that can build Perl.
+However, the generated binaries continue to be incompatible with those
+generated by the other supported compilers (GCC and Visual C++). [561]
+
+=item *
+
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+[561]
+
+=item *
+
+Current directory entries in %ENV are now correctly propagated to child
+processes. [561]
+
+=item *
+
+New %ENV entries now propagate to subprocesses. [561]
+
+=item *
+
+Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
+Other bugs in chdir() and Cwd::cwd() have also been fixed. [561]
+
+=item *
+
+The makefiles now default to the features enabled in ActiveState ActivePerl
+(a popular Win32 binary distribution). [561]
+
+=item *
+
+HTML files will now be installed in c:\perl\html instead of
+c:\perl\lib\pod\html
+
+=item *
+
+REG_EXPAND_SZ keys are now allowed in registry settings used by perl. [561]
+
+=item *
+
+Can now send() from all threads, not just the first one. [561]
+
+=item *
+
+ExtUtils::MakeMaker now uses $ENV{LIB} to search for libraries. [561]
+
+=item *
+
+Less stack reserved per thread so that more threads can run
+concurrently. (Still 16M per thread.) [561]
+
+=item *
+
+C<< File::Spec->tmpdir() >> now prefers C:/temp over /tmp
+(works better when perl is running as service).
+
+=item *
+
+Better UNC path handling under ithreads. [561]
+
+=item *
+
+wait(), waitpid(), and backticks now return the correct exit status
+under Windows 9x. [561]
+
+=item *
+
+A socket handle leak in accept() has been fixed. [561]
+
+=back
+
+=back
+
+=head1 New or Changed Diagnostics
+
+Please see L<perldiag> for more details.
+
+=over 4
+
+=item *
+
+Ambiguous range in the transliteration operator (like a-z-9) now
+gives a warning.
+
+=item *
+
+chdir("") and chdir(undef) now give a deprecation warning because they
+cause a possible unintentional chdir to the home directory.
+Say chdir() if you really mean that.
+
+=item *
+
+Two new debugging options have been added: if you have compiled your
+Perl with debugging, you can use the -DT [561] and -DR options to trace
+tokenising and to add reference counts to displaying variables,
+respectively.
+
+=item *
+
+The lexical warnings category "deprecated" is no longer a sub-category
+of the "syntax" category. It is now a top-level category in its own
+right.
+
+=item *
+
+Unadorned dump() will now give a warning suggesting to
+use explicit CORE::dump() if that's what really is meant.
+
+=item *
+
+The "Unrecognized escape" warning has been extended to include C<\8>,
+C<\9>, and C<\_>. There is no need to escape any of the C<\w> characters.
+
+=item *
+
+All regular expression compilation error messages are now hopefully
+easier to understand both because the error message now comes before
+the failed regex and because the point of failure is now clearly
+marked by a C<E<lt>-- HERE> marker.
+
+=item *
+
+Various I/O (and socket) functions like binmode(), close(), and so
+forth now more consistently warn if they are used illogically either
+on a yet unopened or on an already closed filehandle (or socket).
+
+=item *
+
+Using lstat() on a filehandle now gives a warning. (It's a non-sensical
+thing to do.)
+
+=item *
+
+The C<-M> and C<-m> options now warn if you didn't supply the module name.
+
+=item *
+
+If you in C<use> specify a required minimum version, modules matching
+the name and but not defining a $VERSION will cause a fatal failure.
+
+=item *
+
+Using negative offset for vec() in lvalue context is now a warnable offense.
+
+=item *
+
+Odd number of arguments to overload::constant now elicits a warning.
+
+=item *
+
+Odd number of elements in anonymous hash now elicits a warning.
+
+=item *
+
+The various "opened only for", "on closed", "never opened" warnings
+drop the C<main::> prefix for filehandles in the C<main> package,
+for example C<STDIN> instead of C<main::STDIN>.
+
+=item *
+
+Subroutine prototypes are now checked more carefully, you may
+get warnings for example if you have used non-prototype characters.
+
+=item *
+
+If an attempt to use a (non-blessed) reference as an array index
+is made, a warning is given.
+
+=item *
+
+C<push @a;> and C<unshift @a;> (with no values to push or unshift)
+now give a warning. This may be a problem for generated and eval'ed
+code.
+
+=item *
+
+If you try to L<perlfunc/pack> a number less than 0 or larger than 255
+using the C<"C"> format you will get an optional warning. Similarly
+for the C<"c"> format and a number less than -128 or more than 127.
+
+=item *
+
+pack C<P> format now demands an explicit size.
+
+=item *
+
+unpack C<w> now warns of unterminated compressed integers.
+
+=item *
+
+Warnings relating to the use of PerlIO have been added.
+
+=item *
+
+Certain regex modifiers such as C<(?o)> make sense only if applied to
+the entire regex. You will get an optional warning if you try to do
+otherwise.
+
+=item *
+
+Variable length lookbehind has not yet been implemented, trying to
+use it will tell that.
+
+=item *
+
+Using arrays or hashes as references (e.g. C<< %foo->{bar} >>
+has been deprecated for a while. Now you will get an optional warning.
+
+=item *
+
+Warnings relating to the use of the new restricted hashes feature
+have been added.
+
+=item *
+
+Self-ties of arrays and hashes are not supported and fatal errors
+will happen even at an attempt to do so.
+
+=item *
+
+Using C<sort> in scalar context now issues an optional warning.
+This didn't do anything useful, as the sort was not performed.
+
+=item *
+
+Using the /g modifier in split() is meaningless and will cause a warning.
+
+=item *
+
+Using splice() past the end of an array now causes a warning.
+
+=item *
+
+Malformed Unicode encodings (UTF-8 and UTF-16) cause a lot of warnings,
+as does trying to use UTF-16 surrogates (which are unimplemented).
+
+=item *
+
+Trying to use Unicode characters on an I/O stream without marking the
+stream's encoding (using open() or binmode()) will cause "Wide character"
+warnings.
+
+=item *
+
+Use of v-strings in use/require causes a (backward) portability warning.
+
+=item *
+
+Warnings relating to the use interpreter threads and their shared data
+have been added.
+
+=back
+
+=head1 Changed Internals
+
+=over 4
+
+=item *
+
+PerlIO is now the default.
+
+=item *
+
+perlapi.pod (a companion to perlguts) now attempts to document the
+internal API.
+
+=item *
+
+You can now build a really minimal perl called microperl.
+Building microperl does not require even running Configure;
+C<make -f Makefile.micro> should be enough. Beware: microperl makes
+many assumptions, some of which may be too bold; the resulting
+executable may crash or otherwise misbehave in wondrous ways.
+For careful hackers only.
+
+=item *
+
+Added rsignal(), whichsig(), do_join(), op_clear, op_null,
+ptr_table_clear(), ptr_table_free(), sv_setref_uv(), and several UTF-8
+interfaces to the publicised API. For the full list of the available
+APIs see L<perlapi>.
+
+=item *
+
+Made possible to propagate customised exceptions via croak()ing.
+
+=item *
+
+Now xsubs can have attributes just like subs. (Well, at least the
+built-in attributes.)
+
+=item *
+
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
+
+=item *
+
+PERL_OBJECT has been completely removed.
+
+=item *
+
+The MAGIC constants (e.g. C<'P'>) have been macrofied
+(e.g. C<PERL_MAGIC_TIED>) for better source code readability
+and maintainability.
+
+=item *
+
+The regex compiler now maintains a structure that identifies nodes in
+the compiled bytecode with the corresponding syntactic features of the
+original regex expression. The information is attached to the new
+C<offsets> member of the C<struct regexp>. See L<perldebguts> for more
+complete information.
+
+=item *
+
+The C code has been made much more C<gcc -Wall> clean. Some warning
+messages still remain in some platforms, so if you are compiling with
+gcc you may see some warnings about dubious practices. The warnings
+are being worked on.
+
+=item *
+
+F<perly.c>, F<sv.c>, and F<sv.h> have now been extensively commented.
+
+=item *
+
+Documentation on how to use the Perl source repository has been added
+to F<Porting/repository.pod>.
+
+=item *
+
+There are now several profiling make targets.
+
+=back
+
+=head1 Security Vulnerability Closed [561]
+
+(This change was already made in 5.7.0 but bears repeating here.)
+(5.7.0 came out before 5.6.1: the development branch 5.7 released
+earlier than the maintenance branch 5.6)
+
+A potential security vulnerability in the optional suidperl component
+of Perl was identified in August 2000. suidperl is neither built nor
+installed by default. As of November 2001 the only known vulnerable
+platform is Linux, most likely all Linux distributions. CERT and
+various vendors and distributors have been alerted about the vulnerability.
+See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt
+for more information.
+
+The problem was caused by Perl trying to report a suspected security
+exploit attempt using an external program, /bin/mail. On Linux
+platforms the /bin/mail program had an undocumented feature which
+when combined with suidperl gave access to a root shell, resulting in
+a serious compromise instead of reporting the exploit attempt. If you
+don't have /bin/mail, or if you have 'safe setuid scripts', or if
+suidperl is not installed, you are safe.
+
+The exploit attempt reporting feature has been completely removed from
+Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
+from all the Perl 5.7 releases), so that particular vulnerability
+isn't there anymore. However, further security vulnerabilities are,
+unfortunately, always possible. The suidperl functionality is most
+probably going to be removed in Perl 5.10. In any case, suidperl
+should only be used by security experts who know exactly what they are
+doing and why they are using suidperl instead of some other solution
+such as sudo ( see http://www.courtesan.com/sudo/ ).
+
+=head1 New Tests
+
+Several new tests have been added, especially for the F<lib> and
+F<ext> subsections. There are now about 69 000 individual tests
+(spread over about 700 test scripts), in the regression suite (5.6.1
+has about 11 700 tests, in 258 test scripts) The exact numbers depend
+on the platform and Perl configuration used. Many of the new tests
+are of course introduced by the new modules, but still in general Perl
+is now more thoroughly tested.
+
+Because of the large number of tests, running the regression suite
+will take considerably longer time than it used to: expect the suite
+to take up to 4-5 times longer to run than in perl 5.6. On a really
+fast machine you can hope to finish the suite in about 6-8 minutes
+(wallclock time).
+
+The tests are now reported in a different order than in earlier Perls.
+(This happens because the test scripts from under t/lib have been moved
+to be closer to the library/extension they are testing.)
+
+=head1 Known Problems
+
+=head2 The Compiler Suite Is Still Very Experimental
+
+The compiler suite is slowly getting better but it continues to be
+highly experimental. Use in production environments is discouraged.
+
+=head2 Localising Tied Arrays and Hashes Is Broken
+
+ local %tied_array;
+
+doesn't work as one would expect: the old value is restored
+incorrectly. This will be changed in a future release, but we don't
+know yet what the new semantics will exactly be. In any case, the
+change will break existing code that relies on the current
+(ill-defined) semantics, so just avoid doing this in general.
+
+=head2 Building Extensions Can Fail Because Of Largefiles
+
+Some extensions like mod_perl are known to have issues with
+`largefiles', a change brought by Perl 5.6.0 in which file offsets
+default to 64 bits wide, where supported. Modules may fail to compile
+at all, or they may compile and work incorrectly. Currently, there
+is no good solution for the problem, but Configure now provides
+appropriate non-largefile ccflags, ldflags, libswanted, and libs
+in the %Config hash (e.g., $Config{ccflags_nolargefiles}) so the
+extensions that are having problems can try configuring themselves
+without the largefileness. This is admittedly not a clean solution,
+and the solution may not even work at all. One potential failure is
+whether one can (or, if one can, whether it's a good idea to) link
+together at all binaries with different ideas about file offsets;
+all this is platform-dependent.
+
+=head2 Modifying $_ Inside for(..)
+
+ for (1..5) { $_++ }
+
+works without complaint. It shouldn't. (You should be able to
+modify only lvalue elements inside the loops.) You can see the
+correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
+
+=head2 mod_perl 1.26 Doesn't Build With Threaded Perl
+
+Use mod_perl 1.27 or higher.
+
+=head2 lib/ftmp-security tests warn 'system possibly insecure'
+
+Don't panic. Read the 'make test' section of INSTALL instead.
+
+=head2 libwww-perl (LWP) fails base/date #51
+
+Use libwww-perl 5.65 or later.
+
+=head2 PDL failing some tests
+
+Use PDL 2.3.4 or later.
+
+=head2 Perl_get_sv
+
+You may get errors like 'Undefined symbol "Perl_get_sv"' or "can't
+resolve symbol 'Perl_get_sv'", or the symbol may be "Perl_sv_2pv".
+This probably means that you are trying to use an older shared Perl
+library (or extensions linked with such) with Perl 5.8.0 executable.
+Perl used to have such a subroutine, but that is no more the case.
+Check your shared library path, and any shared Perl libraries in those
+directories.
+
+Sometimes this problem may also indicate a partial Perl 5.8.0
+installation, see L</"Mac OS X dyld undefined symbols"> for an
+example and how to deal with it.
+
+=head2 Self-tying Problems
+
+Self-tying of arrays and hashes is broken in rather deep and
+hard-to-fix ways. As a stop-gap measure to avoid people from getting
+frustrated at the mysterious results (core dumps, most often), it is
+forbidden for now (you will get a fatal error even from an attempt).
+
+A change to self-tying of globs has caused them to be recursively
+referenced (see: L<perlobj/"Two-Phased Garbage Collection">). You
+will now need an explicit untie to destroy a self-tied glob. This
+behaviour may be fixed at a later date.
+
+Self-tying of scalars and IO thingies works.
+
+=head2 ext/threads/t/libc
+
+If this test fails, it indicates that your libc (C library) is not
+threadsafe. This particular test stress tests the localtime() call to
+find out whether it is threadsafe. See L<perlthrtut> for more information.
+
+=head2 Failure of Thread (5.005-style) tests
+
+B<Note that support for 5.005-style threading is deprecated,
+experimental and practically unsupported. In 5.10, it is expected
+to be removed. You should migrate your code to ithreads.>
+
+The following tests are known to fail due to fundamental problems in
+the 5.005 threading implementation. These are not new failures--Perl
+5.005_0x has the same bugs, but didn't have these tests.
+
+ ../ext/B/t/xref.t 255 65280 14 12 85.71% 3-14
+ ../ext/List/Util/t/first.t 255 65280 7 4 57.14% 2 5-7
+ ../lib/English.t 2 512 54 2 3.70% 2-3
+ ../lib/FileCache.t 5 1 20.00% 5
+ ../lib/Filter/Simple/t/data.t 6 3 50.00% 1-3
+ ../lib/Filter/Simple/t/filter_only. 9 3 33.33% 1-2 5
+ ../lib/Math/BigInt/t/bare_mbf.t 1627 4 0.25% 8 11 1626-1627
+ ../lib/Math/BigInt/t/bigfltpm.t 1629 4 0.25% 10 13 1628-
+ 1629
+ ../lib/Math/BigInt/t/sub_mbf.t 1633 4 0.24% 8 11 1632-1633
+ ../lib/Math/BigInt/t/with_sub.t 1628 4 0.25% 9 12 1627-1628
+ ../lib/Tie/File/t/31_autodefer.t 255 65280 65 32 49.23% 34-65
+ ../lib/autouse.t 10 1 10.00% 4
+ op/flip.t 15 1 6.67% 15
+
+These failures are unlikely to get fixed as 5.005-style threads
+are considered fundamentally broken. (Basically what happens is that
+competing threads can corrupt shared global state, one good example
+being regular expression engine's state.)
+
+=head2 Timing problems
+
+The following tests may fail intermittently because of timing
+problems, for example if the system is heavily loaded.
+
+ t/op/alarm.t
+ ext/Time/HiRes/HiRes.t
+ lib/Benchmark.t
+ lib/Memoize/t/expmod_t.t
+ lib/Memoize/t/speed.t
+
+In case of failure please try running them manually, for example
+
+ ./perl -Ilib ext/Time/HiRes/HiRes.t
+
+=head2 Tied/Magical Array/Hash Elements Do Not Autovivify
+
+For normal arrays C<$foo = \$bar[1]> will assign C<undef> to
+C<$bar[1]> (assuming that it didn't exist before), but for
+tied/magical arrays and hashes such autovivification does not happen
+because there is currently no way to catch the reference creation.
+The same problem affects slicing over non-existent indices/keys of
+a tied/magical array/hash.
+
+=head2 Unicode in package/class and subroutine names does not work
+
+One can have Unicode in identifier names, but not in package/class or
+subroutine names. While some limited functionality towards this does
+exist as of Perl 5.8.0, that is more accidental than designed; use of
+Unicode for the said purposes is unsupported.
+
+One reason of this unfinishedness is its (currently) inherent
+unportability: since both package names and subroutine names may
+need to be mapped to file and directory names, the Unicode capability
+of the filesystem becomes important-- and there unfortunately aren't
+portable answers.
+
+=head1 Platform Specific Problems
+
+=head2 AIX
+
+=over 4
+
+=item *
+
+If using the AIX native make command, instead of just "make" issue
+"make all". In some setups the former has been known to spuriously
+also try to run "make install". Alternatively, you may want to use
+GNU make.
+
+=item *
+
+In AIX 4.2, Perl extensions that use C++ functions that use statics
+may have problems in that the statics are not getting initialized.
+In newer AIX releases, this has been solved by linking Perl with
+the libC_r library, but unfortunately in AIX 4.2 the said library
+has an obscure bug where the various functions related to time
+(such as time() and gettimeofday()) return broken values, and
+therefore in AIX 4.2 Perl is not linked against libC_r.
+
+=item *
+
+vac 5.0.0.0 May Produce Buggy Code For Perl
+
+The AIX C compiler vac version 5.0.0.0 may produce buggy code,
+resulting in a few random tests failing when run as part of "make
+test", but when the failing tests are run by hand, they succeed.
+We suggest upgrading to at least vac version 5.0.1.0, that has been
+known to compile Perl correctly. "lslpp -L|grep vac.C" will tell
+you the vac version. See README.aix.
+
+=item *
+
+If building threaded Perl, you may get compilation warning from pp_sys.c:
+
+ "pp_sys.c", line 4651.39: 1506-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
+
+This is harmless; it is caused by the getnetbyaddr() and getnetbyaddr_r()
+having slightly different types for their first argument.
+
+=back
+
+=head2 Alpha systems with old gccs fail several tests
+
+If you see op/pack, op/pat, op/regexp, or ext/Storable tests failing
+in a Linux/alpha or *BSD/Alpha, it's probably time to upgrade your gcc.
+gccs prior to 2.95.3 are definitely not good enough, and gcc 3.1 may
+be even better. (RedHat Linux/alpha with gcc 3.1 reported no problems,
+as did Linux 2.4.18 with gcc 2.95.4.) (In Tru64, it is preferable to
+use the bundled C compiler.)
+
+=head2 AmigaOS
+
+Perl 5.8.0 doesn't build in AmigaOS. It broke at some point during
+the ithreads work and we could not find Amiga experts to unbreak the
+problems. Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
+development release).
+
+=head2 BeOS
+
+The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
+
+ t/op/lfs............................FAILED at test 17
+ t/op/magic..........................FAILED at test 24
+ ext/Fcntl/t/syslfs..................FAILED at test 17
+ ext/File/Glob/t/basic...............FAILED at test 3
+ ext/POSIX/t/sigaction...............FAILED at test 13
+ ext/POSIX/t/waitpid.................FAILED at test 1
+
+See L<perlbeos> (README.beos) for more details.
+
+=head2 Cygwin "unable to remap"
+
+For example when building the Tk extension for Cygwin,
+you may get an error message saying "unable to remap".
+This is known problem with Cygwin, and a workaround is
+detailed in here: http://sources.redhat.com/ml/cygwin/2001-12/msg00894.html
+
+=head2 Cygwin ndbm tests fail on FAT
+
+One can build but not install (or test the build of) the NDBM_File
+on FAT filesystems. Installation (or build) on NTFS works fine.
+If one attempts the test on a FAT install (or build) the following
+failures are expected:
+
+ ../ext/NDBM_File/ndbm.t 13 3328 71 59 83.10% 1-2 4 16-71
+ ../ext/ODBM_File/odbm.t 255 65280 ?? ?? % ??
+ ../lib/AnyDBM_File.t 2 512 12 2 16.67% 1 4
+ ../lib/Memoize/t/errors.t 0 139 11 5 45.45% 7-11
+ ../lib/Memoize/t/tie_ndbm.t 13 3328 4 4 100.00% 1-4
+ run/fresh_perl.t 97 1 1.03% 91
+
+NDBM_File fails and ODBM_File just coredumps.
+
+If you intend to run only on FAT (or if using AnyDBM_File on FAT),
+run Configure with the -Ui_ndbm and -Ui_dbm options to prevent
+NDBM_File and ODBM_File being built.
+
+=head2 DJGPP Failures
+
+ t/op/stat............................FAILED at test 29
+ lib/File/Find/t/find.................FAILED at test 1
+ lib/File/Find/t/taint................FAILED at test 1
+ lib/h2xs.............................FAILED at test 15
+ lib/Pod/t/eol........................FAILED at test 1
+ lib/Test/Harness/t/strap-analyze.....FAILED at test 8
+ lib/Test/Harness/t/test-harness......FAILED at test 23
+ lib/Test/Simple/t/exit...............FAILED at test 1
+
+The above failures are known as of 5.8.0 with native builds with long
+filenames, but there are a few more if running under dosemu because of
+limitations (and maybe bugs) of dosemu:
+
+ t/comp/cpp...........................FAILED at test 3
+ t/op/inccode.........................(crash)
+
+and a few lib/ExtUtils tests, and several hundred Encode/t/Aliases.t
+failures that work fine with long filenames. So you really might
+prefer native builds and long filenames.
+
+=head2 FreeBSD built with ithreads coredumps reading large directories
+
+This is a known bug in FreeBSD 4.5's readdir_r(), it has been fixed in
+FreeBSD 4.6 (see L<perlfreebsd> (README.freebsd)).
+
+=head2 FreeBSD Failing locale Test 117 For ISO 8859-15 Locales
+
+The ISO 8859-15 locales may fail the locale test 117 in FreeBSD.
+This is caused by the characters \xFF (y with diaeresis) and \xBE
+(Y with diaeresis) not behaving correctly when being matched
+case-insensitively. Apparently this problem has been fixed in
+the latest FreeBSD releases.
+( http://www.freebsd.org/cgi/query-pr.cgi?pr=34308 )
+
+=head2 IRIX fails ext/List/Util/t/shuffle.t or Digest::MD5
+
+IRIX with MIPSpro 7.3.1.2m or 7.3.1.3m compiler may fail the List::Util
+test ext/List/Util/t/shuffle.t by dumping core. This seems to be
+a compiler error since if compiled with gcc no core dump ensues, and
+no failures have been seen on the said test on any other platform.
+
+Similarly, building the Digest::MD5 extension has been
+known to fail with "*** Termination code 139 (bu21)".
+
+The cure is to drop optimization level (Configure -Doptimize=-O2).
+
+=head2 HP-UX lib/posix Subtest 9 Fails When LP64-Configured
+
+If perl is configured with -Duse64bitall, the successful result of the
+subtest 10 of lib/posix may arrive before the successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+
+=head2 Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
+
+This is a known bug in the glibc 2.2.5 with long long integers.
+( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=65612 )
+
+=head2 Linux With Sfio Fails op/misc Test 48
+
+No known fix.
+
+=head2 Mac OS X
+
+Please remember to set your environment variable LC_ALL to "C"
+(setenv LC_ALL C) before running "make test" to avoid a lot of
+warnings about the broken locales of Mac OS X.
+
+The following tests are known to fail in Mac OS X 10.1.5 because of
+buggy (old) implementations of Berkeley DB included in Mac OS X:
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ -------------------------------------------------------------------------
+ ../ext/DB_File/t/db-btree.t 0 11 ?? ?? % ??
+ ../ext/DB_File/t/db-recno.t 149 3 2.01% 61 63 65
+
+If you are building on a UFS partition, you will also probably see
+t/op/stat.t subtest #9 fail. This is caused by Darwin's UFS not
+supporting inode change time.
+
+Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
+now because the failure is Apple's fault, not Perl's (blocked signals
+are lost).
+
+If you Configure with ithreads, ext/threads/t/libc.t will fail. Again,
+this is not Perl's fault-- the libc of Mac OS X is not threadsafe
+(in this particular test, the localtime() call is found to be
+threadunsafe.)
+
+=head2 Mac OS X dyld undefined symbols
+
+If after installing Perl 5.8.0 you are getting warnings about missing
+symbols, for example
+
+ dyld: perl Undefined symbols
+ _perl_sv_2pv
+ _perl_get_sv
+
+you probably have an old pre-Perl-5.8.0 installation (or parts of one)
+in /Library/Perl (the undefined symbols used to exist in pre-5.8.0 Perls).
+It seems that for some reason "make install" doesn't always completely
+overwrite the files in /Library/Perl. You can move the old Perl
+shared library out of the way like this:
+
+ cd /Library/Perl/darwin/CORE
+ mv libperl.dylib libperlold.dylib
+
+and then reissue "make install". Note that the above of course is
+extremely disruptive for anything using the /usr/local/bin/perl.
+If that doesn't help, you may have to try removing all the .bundle
+files from beneath /Library/Perl, and again "make install"-ing.
+
+=head2 OS/2 Test Failures
+
+The following tests are known to fail on OS/2 (for clarity
+only the failures are shown, not the full error messages):
+
+ ../lib/ExtUtils/t/Mkbootstrap.t 1 256 18 1 5.56% 8
+ ../lib/ExtUtils/t/Packlist.t 1 256 34 1 2.94% 17
+ ../lib/ExtUtils/t/basic.t 1 256 17 1 5.88% 14
+ lib/os2_process.t 2 512 227 2 0.88% 174 209
+ lib/os2_process_kid.t 227 2 0.88% 174 209
+ lib/rx_cmprt.t 255 65280 18 3 16.67% 16-18
+
+=head2 op/sprintf tests 91, 129, and 130
+
+The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
+Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
+
+Test 91 is known to fail on QNX6 (nto), because C<sprintf '%e',0>
+incorrectly produces C<0.000000e+0> instead of C<0.000000e+00>.
+
+For tests 129 and 130, the failing platforms do not comply with
+the ANSI C Standard: lines 19ff on page 134 of ANSI X3.159 1989, to
+be exact. (They produce something other than "1" and "-1" when
+formatting 0.6 and -0.6 using the printf format "%.0f"; most often,
+they produce "0" and "-0".)
+
+=head2 SCO
+
+The socketpair tests are known to be unhappy in SCO 3.2v5.0.4:
+
+ ext/Socket/socketpair.t...............FAILED tests 15-45
+
+=head2 Solaris 2.5
+
+In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
+experience failures (the test core dumping) in lib/locale.t.
+The suggested cure is to upgrade your Solaris.
+
+=head2 Solaris x86 Fails Tests With -Duse64bitint
+
+The following tests are known to fail in Solaris x86 with Perl
+configured to use 64 bit integers:
+
+ ext/Data/Dumper/t/dumper.............FAILED at test 268
+ ext/Devel/Peek/Peek..................FAILED at test 7
+
+=head2 SUPER-UX (NEC SX)
+
+The following tests are known to fail on SUPER-UX:
+
+ op/64bitint...........................FAILED tests 29-30, 32-33, 35-36
+ op/arith..............................FAILED tests 128-130
+ op/pack...............................FAILED tests 25-5625
+ op/pow................................
+ op/taint..............................# msgsnd failed
+ ../ext/IO/lib/IO/t/io_poll............FAILED tests 3-4
+ ../ext/IPC/SysV/ipcsysv...............FAILED tests 2, 5-6
+ ../ext/IPC/SysV/t/msg.................FAILED tests 2, 4-6
+ ../ext/Socket/socketpair..............FAILED tests 12
+ ../lib/IPC/SysV.......................FAILED tests 2, 5-6
+ ../lib/warnings.......................FAILED tests 115-116, 118-119
+
+The op/pack failure ("Cannot compress negative numbers at op/pack.t line 126")
+is serious but as of yet unsolved. It points at some problems with the
+signedness handling of the C compiler, as do the 64bitint, arith, and pow
+failures. Most of the rest point at problems with SysV IPC.
+
+=head2 Term::ReadKey not working on Win32
+
+Use Term::ReadKey 2.20 or later.
+
+=head2 UNICOS/mk
+
+=over 4
+
+=item *
+
+During Configure, the test
+
+ Guessing which symbols your C compiler and preprocessor define...
+
+will probably fail with error messages like
+
+ CC-20 cc: ERROR File = try.c, Line = 3
+ The identifier "bad" is undefined.
+
+ bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
+ ^
+
+ CC-65 cc: ERROR File = try.c, Line = 3
+ A semicolon is expected at this point.
+
+This is caused by a bug in the awk utility of UNICOS/mk. You can ignore
+the error, but it does cause a slight problem: you cannot fully
+benefit from the h2ph utility (see L<h2ph>) that can be used to
+convert C headers to Perl libraries, mainly used to be able to access
+from Perl the constants defined using C preprocessor, cpp. Because of
+the above error, parts of the converted headers will be invisible.
+Luckily, these days the need for h2ph is rare.
+
+=item *
+
+If building Perl with interpreter threads (ithreads), the
+getgrent(), getgrnam(), and getgrgid() functions cannot return the
+list of the group members due to a bug in the multithreaded support of
+UNICOS/mk. What this means is that in list context the functions will
+return only three values, not four.
+
+=back
+
+=head2 UTS
+
+There are a few known test failures, see L<perluts> (README.uts).
+
+=head2 VOS (Stratus)
+
+When Perl is built using the native build process on VOS Release
+14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
+pass or result in TODO (ignored) failures.
+
+=head2 VMS
+
+There should be no reported test failures with a default configuration,
+though there are a number of tests marked TODO that point to areas
+needing further debugging and/or porting work.
+
+=head2 Win32
+
+In multi-CPU boxes, there are some problems with the I/O buffering:
+some output may appear twice.
+
+=head2 XML::Parser not working
+
+Use XML::Parser 2.31 or later.
+
+=head2 z/OS (OS/390)
+
+z/OS has rather many test failures but the situation is actually much
+better than it was in 5.6.0; it's just that so many new modules and
+tests have been added.
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ ---------------------------------------------------------------------------
+ ../ext/Data/Dumper/t/dumper.t 357 8 2.24% 311 314 325 327
+ 331 333 337 339
+ ../ext/IO/lib/IO/t/io_unix.t 5 4 80.00% 2-5
+ ../ext/Storable/t/downgrade.t 12 3072 169 12 7.10% 14-15 46-47 78-79
+ 110-111 150 161
+ ../lib/ExtUtils/t/Constant.t 121 30976 48 48 100.00% 1-48
+ ../lib/ExtUtils/t/Embed.t 9 9 100.00% 1-9
+ op/pat.t 922 7 0.76% 665 776 785 832-
+ 834 845
+ op/sprintf.t 224 3 1.34% 98 100 136
+ op/tr.t 97 5 5.15% 63 71-74
+ uni/fold.t 780 6 0.77% 61 169 196 661
+ 710-711
+
+The failures in dumper.t and downgrade.t are problems in the tests,
+those in io_unix and sprintf are problems in the USS (UDP sockets and
+printf formats). The pat, tr, and fold failures are genuine Perl
+problems caused by EBCDIC (and in the pat and fold cases, combining
+that with Unicode). The Constant and Embed are probably problems in
+the tests (since they test Perl's ability to build extensions, and
+that seems to be working reasonably well.)
+
+=head2 Unicode Support on EBCDIC Still Spotty
+
+Though mostly working, Unicode support still has problem spots on
+EBCDIC platforms. One such known spot are the C<\p{}> and C<\P{}>
+regular expression constructs for code points less than 256: the
+C<pP> are testing for Unicode code points, not knowing about EBCDIC.
+
+=head2 Seen In Perl 5.7 But Gone Now
+
+C<Time::Piece> (previously known as C<Time::Object>) was removed
+because it was felt that it didn't have enough value in it to be a
+core module. It is still a useful module, though, and is available
+from the CPAN.
+
+Perl 5.8 unfortunately does not build anymore on AmigaOS; this broke
+accidentally at some point. Since there are not that many Amiga
+developers available, we could not get this fixed and tested in time
+for 5.8.0. Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
+development release).
+
+The C<PerlIO::Scalar> and C<PerlIO::Via> (capitalised) were renamed as
+C<PerlIO::scalar> and C<PerlIO::via> (all lowercase) just before 5.8.0.
+The main rationale was to have all core PerlIO layers to have all
+lowercase names. The "plugins" are named as usual, for example
+C<PerlIO::via::QuotedPrint>.
+
+The C<threads::shared::queue> and C<threads::shared::semaphore> were
+renamed as C<Thread::Queue> and C<Thread::Semaphore> just before 5.8.0.
+The main rationale was to have thread modules to obey normal naming,
+C<Thread::> (the C<threads> and C<threads::shared> themselves are
+more pragma-like, they affect compile-time, so they stay lowercase).
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ . There may also be
+information at http://www.perl.com/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=head1 HISTORY
+
+Written by Jarkko Hietaniemi <F<jhi@iki.fi>>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl590delta.pod b/Master/tlpkg/tlperl/lib/pods/perl590delta.pod
new file mode 100644
index 00000000000..a19bf7a0768
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl590delta.pod
@@ -0,0 +1,1015 @@
+=head1 NAME
+
+perl590delta - what is new for perl v5.9.0
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.8.0 release and
+the 5.9.0 release.
+
+=head1 Incompatible Changes
+
+=head2 Hash Randomisation
+
+Mainly due to security reasons, the "random ordering" of hashes
+has been made even more random. Previously while the order of hash
+elements from keys(), values(), and each() was essentially random,
+it was still repeatable. Now, however, the order varies between
+different runs of Perl.
+
+B<Perl has never guaranteed any ordering of the hash keys>, and the
+ordering has already changed several times during the lifetime of
+Perl 5. Also, the ordering of hash keys has always been, and
+continues to be, affected by the insertion order.
+
+The added randomness may affect applications.
+
+One possible scenario is when output of an application has included
+hash data. For example, if you have used the Data::Dumper module to
+dump data into different files, and then compared the files to see
+whether the data has changed, now you will have false positives since
+the order in which hashes are dumped will vary. In general the cure
+is to sort the keys (or the values); in particular for Data::Dumper to
+use the C<Sortkeys> option. If some particular order is really
+important, use tied hashes: for example the Tie::IxHash module
+which by default preserves the order in which the hash elements
+were added.
+
+More subtle problem is reliance on the order of "global destruction".
+That is what happens at the end of execution: Perl destroys all data
+structures, including user data. If your destructors (the DESTROY
+subroutines) have assumed any particular ordering to the global
+destruction, there might be problems ahead. For example, in a
+destructor of one object you cannot assume that objects of any other
+class are still available, unless you hold a reference to them.
+If the environment variable PERL_DESTRUCT_LEVEL is set to a non-zero
+value, or if Perl is exiting a spawned thread, it will also destruct
+the ordinary references and the symbol tables that are no longer in use.
+You can't call a class method or an ordinary function on a class that
+has been collected that way.
+
+The hash randomisation is certain to reveal hidden assumptions about
+some particular ordering of hash elements, and outright bugs: it
+revealed a few bugs in the Perl core and core modules.
+
+To disable the hash randomisation in runtime, set the environment
+variable PERL_HASH_SEED to 0 (zero) before running Perl (for more
+information see L<perlrun/PERL_HASH_SEED>), or to disable the feature
+completely in compile time, compile with C<-DNO_HASH_SEED> (see F<INSTALL>).
+
+See L<perlsec/"Algorithmic Complexity Attacks"> for the original
+rationale behind this change.
+
+=head2 UTF-8 On Filehandles No Longer Activated By Locale
+
+In Perl 5.8.0 all filehandles, including the standard filehandles,
+were implicitly set to be in Unicode UTF-8 if the locale settings
+indicated the use of UTF-8. This feature caused too many problems,
+so the feature was turned off and redesigned: see L</"Core Enhancements">.
+
+=head2 Single-number v-strings are no longer v-strings before "=>"
+
+The version strings or v-strings (see L<perldata/"Version Strings">)
+feature introduced in Perl 5.6.0 has been a source of some confusion--
+especially when the user did not want to use it, but Perl thought it
+knew better. Especially troublesome has been the feature that before
+a "=>" a version string (a "v" followed by digits) has been interpreted
+as a v-string instead of a string literal. In other words:
+
+ %h = ( v65 => 42 );
+
+has meant since Perl 5.6.0
+
+ %h = ( 'A' => 42 );
+
+(at least in platforms of ASCII progeny) Perl 5.8.1 restored the
+more natural interpretation
+
+ %h = ( 'v65' => 42 );
+
+The multi-number v-strings like v65.66 and 65.66.67 still continue to
+be v-strings in Perl 5.8.
+
+=head2 (Win32) The -C Switch Has Been Repurposed
+
+The -C switch has changed in an incompatible way. The old semantics
+of this switch only made sense in Win32 and only in the "use utf8"
+universe in 5.6.x releases, and do not make sense for the Unicode
+implementation in 5.8.0. Since this switch could not have been used
+by anyone, it has been repurposed. The behavior that this switch
+enabled in 5.6.x releases may be supported in a transparent,
+data-dependent fashion in a future release.
+
+For the new life of this switch, see L<"UTF-8 no longer default under
+UTF-8 locales">, and L<perlrun/-C>.
+
+=head2 (Win32) The /d Switch Of cmd.exe
+
+Since version 5.8.1, perl uses the /d switch when running the cmd.exe shell
+internally for system(), backticks, and when opening pipes to external
+programs. The extra switch disables the execution of AutoRun commands
+from the registry, which is generally considered undesirable when
+running external programs. If you wish to retain compatibility with
+the older behavior, set PERL5SHELL in your environment to C<cmd /x/c>.
+
+=head2 The C<$*> variable has been removed
+
+C<$*>, which was deprecated in favor of the C</s> and C</m> regexp
+modifiers, has been removed.
+
+=head1 Core Enhancements
+
+=head2 Assertions
+
+Perl 5.9.0 has experimental support for assertions. Note that the user
+interface is not fully stabilized yet, and it may change until the 5.10.0
+release. A new command-line switch, B<-A>, is used to activate
+assertions, which are declared with the C<assertions> pragma. See
+L<assertions>.
+
+=head2 Defined-or operators
+
+A new operator C<//> (defined-or) has been implemented.
+The following statement:
+
+ $a // $b
+
+is merely equivalent to
+
+ defined $a ? $a : $b
+
+and
+
+ $c //= $d;
+
+can be used instead of
+
+ $c = $d unless defined $c;
+
+This operator has the same precedence and associativity as C<||>.
+It has a low-precedence counterpart, C<err>, which has the same precedence
+and associativity as C<or>. Special care has been taken to ensure that
+those operators Do What You Mean while not breaking old code, but some
+edge cases involving the empty regular expression may now parse
+differently. See L<perlop> for details.
+
+=head2 UTF-8 no longer default under UTF-8 locales
+
+In Perl 5.8.0 many Unicode features were introduced. One of them
+was found to be of more nuisance than benefit: the automagic
+(and silent) "UTF-8-ification" of filehandles, including the
+standard filehandles, if the user's locale settings indicated
+use of UTF-8.
+
+For example, if you had C<en_US.UTF-8> as your locale, your STDIN and
+STDOUT were automatically "UTF-8", in other words an implicit
+binmode(..., ":utf8") was made. This meant that trying to print, say,
+chr(0xff), ended up printing the bytes 0xc3 0xbf. Hardly what
+you had in mind unless you were aware of this feature of Perl 5.8.0.
+The problem is that the vast majority of people weren't: for example
+in RedHat releases 8 and 9 the B<default> locale setting is UTF-8, so
+all RedHat users got UTF-8 filehandles, whether they wanted it or not.
+The pain was intensified by the Unicode implementation of Perl 5.8.0
+(still) having nasty bugs, especially related to the use of s/// and
+tr///. (Bugs that have been fixed in 5.8.1)
+
+Therefore a decision was made to backtrack the feature and change it
+from implicit silent default to explicit conscious option. The new
+Perl command line option C<-C> and its counterpart environment
+variable PERL_UNICODE can now be used to control how Perl and Unicode
+interact at interfaces like I/O and for example the command line
+arguments. See L<perlrun/-C> and L<perlrun/PERL_UNICODE> for more
+information.
+
+=head2 Unsafe signals again available
+
+In Perl 5.8.0 the so-called "safe signals" were introduced. This
+means that Perl no longer handles signals immediately but instead
+"between opcodes", when it is safe to do so. The earlier immediate
+handling easily could corrupt the internal state of Perl, resulting
+in mysterious crashes.
+
+However, the new safer model has its problems too. Because now an
+opcode, a basic unit of Perl execution, is never interrupted but
+instead let to run to completion, certain operations that can take a
+long time now really do take a long time. For example, certain
+network operations have their own blocking and timeout mechanisms, and
+being able to interrupt them immediately would be nice.
+
+Therefore perl 5.8.1 introduced a "backdoor" to restore the pre-5.8.0
+(pre-5.7.3, really) signal behaviour. Just set the environment variable
+PERL_SIGNALS to C<unsafe>, and the old immediate (and unsafe)
+signal handling behaviour returns. See L<perlrun/PERL_SIGNALS>
+and L<perlipc/"Deferred Signals (Safe Signals)">.
+
+In completely unrelated news, you can now use safe signals with
+POSIX::SigAction. See L<POSIX/POSIX::SigAction>.
+
+=head2 Tied Arrays with Negative Array Indices
+
+Formerly, the indices passed to C<FETCH>, C<STORE>, C<EXISTS>, and
+C<DELETE> methods in tied array class were always non-negative. If
+the actual argument was negative, Perl would call FETCHSIZE implicitly
+and add the result to the index before passing the result to the tied
+array method. This behaviour is now optional. If the tied array class
+contains a package variable named C<$NEGATIVE_INDICES> which is set to
+a true value, negative values will be passed to C<FETCH>, C<STORE>,
+C<EXISTS>, and C<DELETE> unchanged.
+
+=head2 local ${$x}
+
+The syntaxes
+
+ local ${$x}
+ local @{$x}
+ local %{$x}
+
+now do localise variables, given that the $x is a valid variable name.
+
+=head2 Unicode Character Database 4.0.0
+
+The copy of the Unicode Character Database included in Perl 5.8 has
+been updated to 4.0.0 from 3.2.0. This means for example that the
+Unicode character properties are as in Unicode 4.0.0.
+
+=head2 Miscellaneous Enhancements
+
+C<unpack()> now defaults to unpacking the C<$_>.
+
+C<map> in void context is no longer expensive. C<map> is now context
+aware, and will not construct a list if called in void context.
+
+If a socket gets closed by the server while printing to it, the client
+now gets a SIGPIPE. While this new feature was not planned, it fell
+naturally out of PerlIO changes, and is to be considered an accidental
+feature.
+
+PerlIO::get_layers(FH) returns the names of the PerlIO layers
+active on a filehandle.
+
+PerlIO::via layers can now have an optional UTF8 method to
+indicate whether the layer wants to "auto-:utf8" the stream.
+
+utf8::is_utf8() has been added as a quick way to test whether
+a scalar is encoded internally in UTF-8 (Unicode).
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules And Pragmata
+
+The following modules and pragmata have been updated since Perl 5.8.0:
+
+=over 4
+
+=item base
+
+=item B::Bytecode
+
+In much better shape than it used to be. Still far from perfect, but
+maybe worth a try.
+
+=item B::Concise
+
+=item B::Deparse
+
+=item Benchmark
+
+An optional feature, C<:hireswallclock>, now allows for high
+resolution wall clock times (uses Time::HiRes).
+
+=item ByteLoader
+
+See B::Bytecode.
+
+=item bytes
+
+Now has bytes::substr.
+
+=item CGI
+
+=item charnames
+
+One can now have custom character name aliases.
+
+=item CPAN
+
+There is now a simple command line frontend to the CPAN.pm
+module called F<cpan>.
+
+=item Data::Dumper
+
+A new option, Pair, allows choosing the separator between hash keys
+and values.
+
+=item DB_File
+
+=item Devel::PPPort
+
+=item Digest::MD5
+
+=item Encode
+
+Significant updates on the encoding pragma functionality
+(tr/// and the DATA filehandle, formats).
+
+If a filehandle has been marked as to have an encoding, unmappable
+characters are detected already during input, not later (when the
+corrupted data is being used).
+
+The ISO 8859-6 conversion table has been corrected (the 0x30..0x39
+erroneously mapped to U+0660..U+0669, instead of U+0030..U+0039). The
+GSM 03.38 conversion did not handle escape sequences correctly. The
+UTF-7 encoding has been added (making Encode feature-complete with
+Unicode::String).
+
+=item fields
+
+=item libnet
+
+=item Math::BigInt
+
+A lot of bugs have been fixed since v1.60, the version included in Perl
+v5.8.0. Especially noteworthy are the bug in Calc that caused div and mod to
+fail for some large values, and the fixes to the handling of bad inputs.
+
+Some new features were added, e.g. the broot() method, you can now pass
+parameters to config() to change some settings at runtime, and it is now
+possible to trap the creation of NaN and infinity.
+
+As usual, some optimizations took place and made the math overall a tad
+faster. In some cases, quite a lot faster, actually. Especially alternative
+libraries like Math::BigInt::GMP benefit from this. In addition, a lot of the
+quite clunky routines like fsqrt() and flog() are now much much faster.
+
+=item MIME::Base64
+
+=item NEXT
+
+Diamond inheritance now works.
+
+=item Net::Ping
+
+=item PerlIO::scalar
+
+Reading from non-string scalars (like the special variables, see
+L<perlvar>) now works.
+
+=item podlators
+
+=item Pod::LaTeX
+
+=item PodParsers
+
+=item Pod::Perldoc
+
+Complete rewrite. As a side-effect, no longer refuses to startup when
+run by root.
+
+=item Scalar::Util
+
+New utilities: refaddr, isvstring, looks_like_number, set_prototype.
+
+=item Storable
+
+Can now store code references (via B::Deparse, so not foolproof).
+
+=item strict
+
+Earlier versions of the strict pragma did not check the parameters
+implicitly passed to its "import" (use) and "unimport" (no) routine.
+This caused the false idiom such as:
+
+ use strict qw(@ISA);
+ @ISA = qw(Foo);
+
+This however (probably) raised the false expectation that the strict
+refs, vars and subs were being enforced (and that @ISA was somehow
+"declared"). But the strict refs, vars, and subs are B<not> enforced
+when using this false idiom.
+
+Starting from Perl 5.8.1, the above B<will> cause an error to be
+raised. This may cause programs which used to execute seemingly
+correctly without warnings and errors to fail when run under 5.8.1.
+This happens because
+
+ use strict qw(@ISA);
+
+will now fail with the error:
+
+ Unknown 'strict' tag(s) '@ISA'
+
+The remedy to this problem is to replace this code with the correct idiom:
+
+ use strict;
+ use vars qw(@ISA);
+ @ISA = qw(Foo);
+
+=item Term::ANSIcolor
+
+=item Test::Harness
+
+Now much more picky about extra or missing output from test scripts.
+
+=item Test::More
+
+=item Test::Simple
+
+=item Text::Balanced
+
+=item Time::HiRes
+
+Use of nanosleep(), if available, allows mixing subsecond sleeps with
+alarms.
+
+=item threads
+
+Several fixes, for example for join() problems and memory
+leaks. In some platforms (like Linux) that use glibc the minimum memory
+footprint of one ithread has been reduced by several hundred kilobytes.
+
+=item threads::shared
+
+Many memory leaks have been fixed.
+
+=item Unicode::Collate
+
+=item Unicode::Normalize
+
+=item Win32::GetFolderPath
+
+=item Win32::GetOSVersion
+
+Now returns extra information.
+
+=back
+
+=head1 Utility Changes
+
+The C<h2xs> utility now produces a more modern layout:
+F<Foo-Bar/lib/Foo/Bar.pm> instead of F<Foo/Bar/Bar.pm>.
+Also, the boilerplate test is now called F<t/Foo-Bar.t>
+instead of F<t/1.t>.
+
+The Perl debugger (F<lib/perl5db.pl>) has now been extensively
+documented and bugs found while documenting have been fixed.
+
+C<perldoc> has been rewritten from scratch to be more robust and
+feature rich.
+
+C<perlcc -B> works now at least somewhat better, while C<perlcc -c>
+is rather more broken. (The Perl compiler suite as a whole continues
+to be experimental.)
+
+=head1 New Documentation
+
+perl573delta has been added to list the differences between the
+(now quite obsolete) development releases 5.7.2 and 5.7.3.
+
+perl58delta and perl581delta have been added: these are the perldeltas
+of 5.8.0 and 5.8.1, detailing the differences respectively between
+5.6.0 and 5.8.0, and between 5.8.0 and 5.8.1.
+
+perlartistic has been added: it is the Artistic License in pod format,
+making it easier for modules to refer to it.
+
+perlcheat has been added: it is a Perl cheat sheet.
+
+perlgpl has been added: it is the GNU General Public License in pod
+format, making it easier for modules to refer to it.
+
+perlmacosx has been added to tell about the installation and use
+of Perl in Mac OS X.
+
+perlos400 has been added to tell about the installation and use
+of Perl in OS/400 PASE.
+
+perlreref has been added: it is a regular expressions quick reference.
+
+=head1 Installation and Configuration Improvements
+
+The Unix standard Perl location, F</usr/bin/perl>, is no longer
+overwritten by default if it exists. This change was very prudent
+because so many Unix vendors already provide a F</usr/bin/perl>,
+but simultaneously many system utilities may depend on that
+exact version of Perl, so better not to overwrite it.
+
+One can now specify installation directories for site and vendor man
+and HTML pages, and site and vendor scripts. See F<INSTALL>.
+
+One can now specify a destination directory for Perl installation
+by specifying the DESTDIR variable for C<make install>. (This feature
+is slightly different from the previous C<Configure -Dinstallprefix=...>.)
+See F<INSTALL>.
+
+gcc versions 3.x introduced a new warning that caused a lot of noise
+during Perl compilation: C<gcc -Ialreadyknowndirectory (warning:
+changing search order)>. This warning has now been avoided by
+Configure weeding out such directories before the compilation.
+
+One can now build subsets of Perl core modules by using the
+Configure flags C<-Dnoextensions=...> and C<-Donlyextensions=...>,
+see F<INSTALL>.
+
+=head2 Platform-specific enhancements
+
+In Cygwin Perl can now be built with threads (C<Configure -Duseithreads>).
+This works with both Cygwin 1.3.22 and Cygwin 1.5.3.
+
+In newer FreeBSD releases Perl 5.8.0 compilation failed because of
+trying to use F<malloc.h>, which in FreeBSD is just a dummy file, and
+a fatal error to even try to use. Now F<malloc.h> is not used.
+
+Perl is now known to build also in Hitachi HI-UXMPP.
+
+Perl is now known to build again in LynxOS.
+
+Mac OS X now installs with Perl version number embedded in
+installation directory names for easier upgrading of user-compiled
+Perl, and the installation directories in general are more standard.
+In other words, the default installation no longer breaks the
+Apple-provided Perl. On the other hand, with C<Configure -Dprefix=/usr>
+you can now really replace the Apple-supplied Perl (B<please be careful>).
+
+Mac OS X now builds Perl statically by default. This change was done
+mainly for faster startup times. The Apple-provided Perl is still
+dynamically linked and shared, and you can enable the sharedness for
+your own Perl builds by C<Configure -Duseshrplib>.
+
+Perl has been ported to IBM's OS/400 PASE environment. The best way
+to build a Perl for PASE is to use an AIX host as a cross-compilation
+environment. See README.os400.
+
+Yet another cross-compilation option has been added: now Perl builds
+on OpenZaurus, an Linux distribution based on Mandrake + Embedix for
+the Sharp Zaurus PDA. See the Cross/README file.
+
+Tru64 when using gcc 3 drops the optimisation for F<toke.c> to C<-O2>
+because of gigantic memory use with the default C<-O3>.
+
+Tru64 can now build Perl with the newer Berkeley DBs.
+
+Building Perl on WinCE has been much enhanced, see F<README.ce>
+and F<README.perlce>.
+
+=head1 Selected Bug Fixes
+
+=head2 Closures, eval and lexicals
+
+There have been many fixes in the area of anonymous subs, lexicals and
+closures. Although this means that Perl is now more "correct", it is
+possible that some existing code will break that happens to rely on
+the faulty behaviour. In practice this is unlikely unless your code
+contains a very complex nesting of anonymous subs, evals and lexicals.
+
+=head2 Generic fixes
+
+If an input filehandle is marked C<:utf8> and Perl sees illegal UTF-8
+coming in when doing C<< <FH> >>, if warnings are enabled a warning is
+immediately given - instead of being silent about it and Perl being
+unhappy about the broken data later. (The C<:encoding(utf8)> layer
+also works the same way.)
+
+binmode(SOCKET, ":utf8") only worked on the input side, not on the
+output side of the socket. Now it works both ways.
+
+For threaded Perls certain system database functions like getpwent()
+and getgrent() now grow their result buffer dynamically, instead of
+failing. This means that at sites with lots of users and groups the
+functions no longer fail by returning only partial results.
+
+Perl 5.8.0 had accidentally broken the capability for users
+to define their own uppercase<->lowercase Unicode mappings
+(as advertised by the Camel). This feature has been fixed and
+is also documented better.
+
+In 5.8.0 this
+
+ $some_unicode .= <FH>;
+
+didn't work correctly but instead corrupted the data. This has now
+been fixed.
+
+Tied methods like FETCH etc. may now safely access tied values, i.e.
+resulting in a recursive call to FETCH etc. Remember to break the
+recursion, though.
+
+At startup Perl blocks the SIGFPE signal away since there isn't much
+Perl can do about it. Previously this blocking was in effect also for
+programs executed from within Perl. Now Perl restores the original
+SIGFPE handling routine, whatever it was, before running external
+programs.
+
+Linenumbers in Perl scripts may now be greater than 65536, or 2**16.
+(Perl scripts have always been able to be larger than that, it's just
+that the linenumber for reported errors and warnings have "wrapped
+around".) While scripts that large usually indicate a need to rethink
+your code a bit, such Perl scripts do exist, for example as results
+from generated code. Now linenumbers can go all the way to
+4294967296, or 2**32.
+
+=head2 Platform-specific fixes
+
+Linux
+
+=over 4
+
+=item *
+
+Setting $0 works again (with certain limitations that
+Perl cannot do much about: see L<perlvar/$0>)
+
+=back
+
+HP-UX
+
+=over 4
+
+=item *
+
+Setting $0 now works.
+
+=back
+
+VMS
+
+=over 4
+
+=item *
+
+Configuration now tests for the presence of C<poll()>, and IO::Poll
+now uses the vendor-supplied function if detected.
+
+=item *
+
+A rare access violation at Perl start-up could occur if the Perl image was
+installed with privileges or if there was an identifier with the
+subsystem attribute set in the process's rightslist. Either of these
+circumstances triggered tainting code that contained a pointer bug.
+The faulty pointer arithmetic has been fixed.
+
+=item *
+
+The length limit on values (not keys) in the %ENV hash has been raised
+from 255 bytes to 32640 bytes (except when the PERL_ENV_TABLES setting
+overrides the default use of logical names for %ENV). If it is
+necessary to access these long values from outside Perl, be aware that
+they are implemented using search list logical names that store the
+value in pieces, each 255-byte piece (up to 128 of them) being an
+element in the search list. When doing a lookup in %ENV from within
+Perl, the elements are combined into a single value. The existing
+VMS-specific ability to access individual elements of a search list
+logical name via the $ENV{'foo;N'} syntax (where N is the search list
+index) is unimpaired.
+
+=item *
+
+The piping implementation now uses local rather than global DCL
+symbols for inter-process communication.
+
+=item *
+
+File::Find could become confused when navigating to a relative
+directory whose name collided with a logical name. This problem has
+been corrected by adding directory syntax to relative path names, thus
+preventing logical name translation.
+
+=back
+
+Win32
+
+=over 4
+
+=item *
+
+A memory leak in the fork() emulation has been fixed.
+
+=item *
+
+The return value of the ioctl() built-in function was accidentally
+broken in 5.8.0. This has been corrected.
+
+=item *
+
+The internal message loop executed by perl during blocking operations
+sometimes interfered with messages that were external to Perl.
+This often resulted in blocking operations terminating prematurely or
+returning incorrect results, when Perl was executing under environments
+that could generate Windows messages. This has been corrected.
+
+=item *
+
+Pipes and sockets are now automatically in binary mode.
+
+=item *
+
+The four-argument form of select() did not preserve $! (errno) properly
+when there were errors in the underlying call. This is now fixed.
+
+=item *
+
+The "CR CR LF" problem of has been fixed, binmode(FH, ":crlf")
+is now effectively a no-op.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+All the warnings related to pack() and unpack() were made more
+informative and consistent.
+
+=head2 Changed "A thread exited while %d threads were running"
+
+The old version
+
+ A thread exited while %d other threads were still running
+
+was misleading because the "other" included also the thread giving
+the warning.
+
+=head2 Removed "Attempt to clear a restricted hash"
+
+It is not illegal to clear a restricted hash, so the warning
+was removed.
+
+=head2 New "Illegal declaration of anonymous subroutine"
+
+You must specify the block of code for C<sub>.
+
+=head2 Changed "Invalid range "%s" in transliteration operator"
+
+The old version
+
+ Invalid [] range "%s" in transliteration operator
+
+was simply wrong because there are no "[] ranges" in tr///.
+
+=head2 New "Missing control char name in \c"
+
+Self-explanatory.
+
+=head2 New "Newline in left-justified string for %s"
+
+The padding spaces would appear after the newline, which is
+probably not what you had in mind.
+
+=head2 New "Possible precedence problem on bitwise %c operator"
+
+If you think this
+
+ $x & $y == 0
+
+tests whether the bitwise AND of $x and $y is zero,
+you will like this warning.
+
+=head2 New "read() on %s filehandle %s"
+
+You cannot read() (or sysread()) from a closed or unopened filehandle.
+
+=head2 New "Tied variable freed while still in use"
+
+Something pulled the plug on a live tied variable, Perl plays
+safe by bailing out.
+
+=head2 New "To%s: illegal mapping '%s'"
+
+An illegal user-defined Unicode casemapping was specified.
+
+=head2 New "Use of freed value in iteration"
+
+Something modified the values being iterated over. This is not good.
+
+=head1 Changed Internals
+
+These news matter to you only if you either write XS code or like to
+know about or hack Perl internals (using Devel::Peek or any of the
+C<B::> modules counts), or like to run Perl with the C<-D> option.
+
+The embedding examples of L<perlembed> have been reviewed to be
+up to date and consistent: for example, the correct use of
+PERL_SYS_INIT3() and PERL_SYS_TERM().
+
+Extensive reworking of the pad code (the code responsible
+for lexical variables) has been conducted by Dave Mitchell.
+
+Extensive work on the v-strings by John Peacock.
+
+UTF-8 length and position cache: to speed up the handling of Unicode
+(UTF-8) scalars, a cache was introduced. Potential problems exist if
+an extension bypasses the official APIs and directly modifies the PV
+of an SV: the UTF-8 cache does not get cleared as it should.
+
+APIs obsoleted in Perl 5.8.0, like sv_2pv, sv_catpvn, sv_catsv,
+sv_setsv, are again available.
+
+Certain Perl core C APIs like cxinc and regatom are no longer
+available at all to code outside the Perl core of the Perl core
+extensions. This is intentional. They never should have been
+available with the shorter names, and if you application depends on
+them, you should (be ashamed and) contact perl5-porters to discuss
+what are the proper APIs.
+
+Certain Perl core C APIs like C<Perl_list> are no longer available
+without their C<Perl_> prefix. If your XS module stops working
+because some functions cannot be found, in many cases a simple fix is
+to add the C<Perl_> prefix to the function and the thread context
+C<aTHX_> as the first argument of the function call. This is also how
+it should always have been done: letting the Perl_-less forms to leak
+from the core was an accident. For cleaner embedding you can also
+force this for all APIs by defining at compile time the cpp define
+PERL_NO_SHORT_NAMES.
+
+Perl_save_bool() has been added.
+
+Regexp objects (those created with C<qr>) now have S-magic rather than
+R-magic. This fixed regexps of the form /...(??{...;$x})/ to no
+longer ignore changes made to $x. The S-magic avoids dropping
+the caching optimization and making (??{...}) constructs obscenely
+slow (and consequently useless). See also L<perlguts/"Magic Variables">.
+Regexp::Copy was affected by this change.
+
+The Perl internal debugging macros DEBUG() and DEB() have been renamed
+to PERL_DEBUG() and PERL_DEB() to avoid namespace conflicts.
+
+C<-DL> removed (the leaktest had been broken and unsupported for years,
+use alternative debugging mallocs or tools like valgrind and Purify).
+
+Verbose modifier C<v> added for C<-DXv> and C<-Dsv>, see L<perlrun>.
+
+=head1 New Tests
+
+In Perl 5.8.0 there were about 69000 separate tests in about 700 test files,
+in Perl 5.9.0 there are about 77000 separate tests in about 780 test files.
+The exact numbers depend on the Perl configuration and on the operating
+system platform.
+
+=head1 Known Problems
+
+The hash randomisation mentioned in L</Incompatible Changes> is definitely
+problematic: it will wake dormant bugs and shake out bad assumptions.
+
+Many of the rarer platforms that worked 100% or pretty close to it
+with perl 5.8.0 have been left a little bit untended since their
+maintainers have been otherwise busy lately, and therefore there will
+be more failures on those platforms. Such platforms include Mac OS
+Classic, IBM z/OS (and other EBCDIC platforms), and NetWare. The most
+common Perl platforms (Unix and Unix-like, Microsoft platforms, and
+VMS) have large enough testing and expert population that they are
+doing well.
+
+=head2 Tied hashes in scalar context
+
+Tied hashes do not currently return anything useful in scalar context,
+for example when used as boolean tests:
+
+ if (%tied_hash) { ... }
+
+The current nonsensical behaviour is always to return false,
+regardless of whether the hash is empty or has elements.
+
+The root cause is that there is no interface for the implementors of
+tied hashes to implement the behaviour of a hash in scalar context.
+
+=head2 Net::Ping 450_service and 510_ping_udp failures
+
+The subtests 9 and 18 of lib/Net/Ping/t/450_service.t, and the
+subtest 2 of lib/Net/Ping/t/510_ping_udp.t might fail if you have
+an unusual networking setup. For example in the latter case the
+test is trying to send a UDP ping to the IP address 127.0.0.1.
+
+=head2 B::C
+
+The C-generating compiler backend B::C (the frontend being
+C<perlcc -c>) is even more broken than it used to be because of
+the extensive lexical variable changes. (The good news is that
+B::Bytecode and ByteLoader are better than they used to be.)
+
+=head1 Platform Specific Problems
+
+=head2 EBCDIC Platforms
+
+IBM z/OS and other EBCDIC platforms continue to be problematic
+regarding Unicode support. Many Unicode tests are skipped when
+they really should be fixed.
+
+=head2 Cygwin 1.5 problems
+
+In Cygwin 1.5 the F<io/tell> and F<op/sysio> tests have failures for
+some yet unknown reason. In 1.5.5 the threads tests stress_cv,
+stress_re, and stress_string are failing unless the environment
+variable PERLIO is set to "perlio" (which makes also the io/tell
+failure go away).
+
+Perl 5.8.1 does build and work well with Cygwin 1.3: with (uname -a)
+C<CYGWIN_NT-5.0 ... 1.3.22(0.78/3/2) 2003-03-18 09:20 i686 ...>
+a 100% "make test" was achieved with C<Configure -des -Duseithreads>.
+
+=head2 HP-UX: HP cc warnings about sendfile and sendpath
+
+With certain HP C compiler releases (e.g. B.11.11.02) you will
+get many warnings like this (lines wrapped for easier reading):
+
+ cc: "/usr/include/sys/socket.h", line 504: warning 562:
+ Redeclaration of "sendfile" with a different storage class specifier:
+ "sendfile" will have internal linkage.
+ cc: "/usr/include/sys/socket.h", line 505: warning 562:
+ Redeclaration of "sendpath" with a different storage class specifier:
+ "sendpath" will have internal linkage.
+
+The warnings show up both during the build of Perl and during certain
+lib/ExtUtils tests that invoke the C compiler. The warning, however,
+is not serious and can be ignored.
+
+=head2 IRIX: t/uni/tr_7jis.t falsely failing
+
+The test t/uni/tr_7jis.t is known to report failure under 'make test'
+or the test harness with certain releases of IRIX (at least IRIX 6.5
+and MIPSpro Compilers Version 7.3.1.1m), but if run manually the test
+fully passes.
+
+=head2 Mac OS X: no usemymalloc
+
+The Perl malloc (C<-Dusemymalloc>) does not work at all in Mac OS X.
+This is not that serious, though, since the native malloc works just
+fine.
+
+=head2 Tru64: No threaded builds with GNU cc (gcc)
+
+In the latest Tru64 releases (e.g. v5.1B or later) gcc cannot be used
+to compile a threaded Perl (-Duseithreads) because the system
+C<< <pthread.h> >> file doesn't know about gcc.
+
+=head2 Win32: sysopen, sysread, syswrite
+
+As of the 5.8.0 release, sysopen()/sysread()/syswrite() do not behave
+like they used to in 5.6.1 and earlier with respect to "text" mode.
+These built-ins now always operate in "binary" mode (even if sysopen()
+was passed the O_TEXT flag, or if binmode() was used on the file
+handle). Note that this issue should only make a difference for disk
+files, as sockets and pipes have always been in "binary" mode in the
+Windows port. As this behavior is currently considered a bug,
+compatible behavior may be re-introduced in a future release. Until
+then, the use of sysopen(), sysread() and syswrite() is not supported
+for "text" mode operations.
+
+=head1 TODO
+
+Here are some things that are planned for perl 5.10.0 :
+
+=over 4
+
+=item *
+
+Various Copy-On-Write techniques will be investigated in hopes
+of speeding up Perl.
+
+=item *
+
+CPANPLUS, Inline, and Module::Build will become core modules.
+
+=item *
+
+The ability to write true lexically scoped pragmas will be introduced,
+perhaps via a C<pragma> pragma.
+
+=item *
+
+Work will continue on the bytecompiler and byteloader.
+
+=item *
+
+v-strings as they currently exist are scheduled to be deprecated. The
+v-less form (1.2.3) will become a "version object" when used with C<use>,
+C<require>, and C<$VERSION>. $^V will also be a "version object" so the
+printf("%vd",...) construct will no longer be needed. The v-ful version
+(v1.2.3) will become obsolete. The equivalence of strings and v-strings (e.g.
+that currently 5.8.0 is equal to "\5\8\0") will go away. B<There may be no
+deprecation warning for v-strings>, though: it is quite hard to detect when
+v-strings are being used safely, and when they are not.
+
+=back
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at F<http://bugs.perl.org/>. There may also be
+information at F<http://www.perl.com/>, the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team. You can browse and search
+the Perl 5 bugs at F<http://bugs.perl.org/>.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl591delta.pod b/Master/tlpkg/tlperl/lib/pods/perl591delta.pod
new file mode 100644
index 00000000000..349c49a40f2
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl591delta.pod
@@ -0,0 +1,323 @@
+=head1 NAME
+
+perl591delta - what is new for perl v5.9.1
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.9.0 and the 5.9.1
+development releases. See L<perl590delta> for the differences between
+5.8.0 and 5.9.0.
+
+=head1 Incompatible Changes
+
+=head2 substr() lvalues are no longer fixed-length
+
+The lvalues returned by the three argument form of substr() used to be a
+"fixed length window" on the original string. In some cases this could
+cause surprising action at distance or other undefined behaviour. Now the
+length of the window adjusts itself to the length of the string assigned to
+it.
+
+=head2 The C<:unique> attribute is only meaningful for globals
+
+Now applying C<:unique> to lexical variables and to subroutines will
+result in a compilation error.
+
+=head1 Core Enhancements
+
+=head2 Lexical C<$_>
+
+The default variable C<$_> can now be lexicalized, by declaring it like
+any other lexical variable, with a simple
+
+ my $_;
+
+The operations that default on C<$_> will use the lexically-scoped
+version of C<$_> when it exists, instead of the global C<$_>.
+
+In a C<map> or a C<grep> block, if C<$_> was previously my'ed, then the
+C<$_> inside the block is lexical as well (and scoped to the block).
+
+In a scope where C<$_> has been lexicalized, you can still have access to
+the global version of C<$_> by using C<$::_>, or, more simply, by
+overriding the lexical declaration with C<our $_>.
+
+=head2 Tied hashes in scalar context
+
+As of perl 5.8.2/5.9.0, tied hashes did not return anything useful in
+scalar context, for example when used as boolean tests:
+
+ if (%tied_hash) { ... }
+
+The old nonsensical behaviour was always to return false,
+regardless of whether the hash is empty or has elements.
+
+There is now an interface for the implementors of tied hashes to implement
+the behaviour of a hash in scalar context, via the SCALAR method (see
+L<perltie>). Without a SCALAR method, perl will try to guess whether
+the hash is empty, by testing if it's inside an iteration (in this case
+it can't be empty) or by calling FIRSTKEY.
+
+=head2 Formats
+
+Formats were improved in several ways. A new field, C<^*>, can be used for
+variable-width, one-line-at-a-time text. Null characters are now handled
+correctly in picture lines. Using C<@#> and C<~~> together will now
+produce a compile-time error, as those format fields are incompatible.
+L<perlform> has been improved, and miscellaneous bugs fixed.
+
+=head2 Stacked filetest operators
+
+As a new form of syntactic sugar, it's now possible to stack up filetest
+operators. You can now write C<-f -w -x $file> in a row to mean
+C<-x $file && -w _ && -f _>. See L<perlfunc/-X>.
+
+=head1 Modules and Pragmata
+
+=over 4
+
+=item Benchmark
+
+In C<Benchmark>, cmpthese() and timestr() now use the time statistics of
+children instead of parent when the selected style is 'nop'.
+
+=item Carp
+
+The error messages produced by C<Carp> now include spaces between the
+arguments in function argument lists: this makes long error messages
+appear more nicely in browsers and other tools.
+
+=item Exporter
+
+C<Exporter> will now recognize grouping tags (such as C<:name>) anywhere
+in the import list, not only at the beginning.
+
+=item FindBin
+
+A function C<again> is provided to resolve problems where modules in different
+directories wish to use FindBin.
+
+=item List::Util
+
+You can now weaken references to read only values.
+
+=item threads::shared
+
+C<cond_wait> has a new two argument form. C<cond_timedwait> has been added.
+
+=back
+
+=head1 Utility Changes
+
+C<find2perl> now assumes C<-print> as a default action. Previously, it
+needed to be specified explicitly.
+
+A new utility, C<prove>, makes it easy to run an individual regression test
+at the command line. C<prove> is part of Test::Harness, which users of earlier
+Perl versions can install from CPAN.
+
+The perl debugger now supports a C<save> command, to save the current
+history to a file, and an C<i> command, which prints the inheritance tree
+of its argument (if the C<Class::ISA> module is installed.)
+
+=head1 Documentation
+
+The documentation has been revised in places to produce more standard manpages.
+
+The long-existing feature of C</(?{...})/> regexps setting C<$_> and pos()
+is now documented.
+
+=head1 Performance Enhancements
+
+Sorting arrays in place (C<@a = sort @a>) is now optimized to avoid
+making a temporary copy of the array.
+
+The operations involving case mapping on UTF-8 strings (uc(), lc(),
+C<//i>, etc.) have been greatly speeded up.
+
+Access to elements of lexical arrays via a numeric constant between 0 and
+255 is now faster. (This used to be only the case for global arrays.)
+
+=head1 Selected Bug Fixes
+
+=head2 UTF-8 bugs
+
+Using substr() on a UTF-8 string could cause subsequent accesses on that
+string to return garbage. This was due to incorrect UTF-8 offsets being
+cached, and is now fixed.
+
+join() could return garbage when the same join() statement was used to
+process 8 bit data having earlier processed UTF-8 data, due to the flags
+on that statement's temporary workspace not being reset correctly. This
+is now fixed.
+
+Using Unicode keys with tied hashes should now work correctly.
+
+chop() and chomp() used to mangle UTF-8 strings. This has been fixed.
+
+sprintf() used to misbehave when the format string was in UTF-8. This is
+now fixed.
+
+=head2 Threading bugs
+
+Hashes with the C<:unique> attribute weren't made read-only in new
+threads. They are now.
+
+=head2 More bugs
+
+C<$a .. $b> will now work as expected when either $a or $b is C<undef>.
+
+Reading $^E now preserves $!. Previously, the C code implementing $^E
+did not preserve C<errno>, so reading $^E could cause C<errno> and therefore
+C<$!> to change unexpectedly.
+
+C<strict> wasn't in effect in regexp-eval blocks (C</(?{...})/>).
+
+=head1 New or Changed Diagnostics
+
+A new deprecation warning, I<Deprecated use of my() in false conditional>,
+has been added, to warn against the use of the dubious and deprecated
+construct
+
+ my $x if 0;
+
+See L<perldiag>.
+
+The fatal error I<DESTROY created new reference to dead object> is now
+documented in L<perldiag>.
+
+A new error, I<%ENV is aliased to %s>, is produced when taint checks are
+enabled and when C<*ENV> has been aliased (and thus doesn't reflect the
+program's environment anymore.)
+
+=head1 Changed Internals
+
+These news matter to you only if you either write XS code or like to
+know about or hack Perl internals (using Devel::Peek or any of the
+C<B::> modules counts), or like to run Perl with the C<-D> option.
+
+=head2 Reordering of SVt_* constants
+
+The relative ordering of constants that define the various types of C<SV>
+have changed; in particular, C<SVt_PVGV> has been moved before C<SVt_PVLV>,
+C<SVt_PVAV>, C<SVt_PVHV> and C<SVt_PVCV>. This is unlikely to make any
+difference unless you have code that explicitly makes assumptions about that
+ordering. (The inheritance hierarchy of C<B::*> objects has been changed
+to reflect this.)
+
+=head2 Removal of CPP symbols
+
+The C preprocessor symbols C<PERL_PM_APIVERSION> and
+C<PERL_XS_APIVERSION>, which were supposed to give the version number of
+the oldest perl binary-compatible (resp. source-compatible) with the
+present one, were not used, and sometimes had misleading values. They have
+been removed.
+
+=head2 Less space is used by ops
+
+The C<BASEOP> structure now uses less space. The C<op_seq> field has been
+removed and replaced by two one-bit fields, C<op_opt> and C<op_static>.
+C<opt_type> is now 9 bits long. (Consequently, the C<B::OP> class doesn't
+provide an C<seq> method anymore.)
+
+=head2 New parser
+
+perl's parser is now generated by bison (it used to be generated by
+byacc.) As a result, it seems to be a bit more robust.
+
+=head1 Configuration and Building
+
+C<Configure> now invokes callbacks regardless of the value of the variable
+they are called for. Previously callbacks were only invoked in the
+C<case $variable $define)> branch. This change should only affect platform
+maintainers writing configuration hints files.
+
+The portability and cleanliness of the Win32 makefiles has been improved.
+
+=head1 Known Problems
+
+There are still a couple of problems in the implementation of the lexical
+C<$_>: it doesn't work inside C</(?{...})/> blocks and with regard to the
+reverse() built-in used without arguments. (See the TODO tests in
+F<t/op/mydef.t>.)
+
+=head2 Platform Specific Problems
+
+The test F<ext/IPC/SysV/t/ipcsysv.t> may fail on OpenBSD. This hasn't been
+diagnosed yet.
+
+On some configurations on AIX 5, one test in F<lib/Time/Local.t> fails.
+When configured with long doubles, perl may fail tests 224-236 in
+F<t/op/pow.t> on the same platform.
+
+For threaded builds, F<ext/threads/shared/t/wait.t> has been reported to
+fail some tests on HP-UX 10.20.
+
+=head1 To-do for perl 5.10.0
+
+This is a non-exhaustive, non-ordered, non-contractual and non-definitive
+list of things to do (or nice to have) for perl 5.10.0 :
+
+Clean up and finish support for assertions. See L<assertions>.
+
+Reimplement the mechanism of lexical pragmas to be more extensible. Fix
+current pragmas that don't work well (or at all) with lexical scopes or in
+run-time eval(STRING) (C<sort>, C<re>, C<encoding> for example). MJD has a
+preliminary patch that implements this.
+
+Fix (or rewrite) the implementation of the C</(?{...})/> closures.
+
+Conversions from byte strings to UTF-8 currently map high bit characters
+to Unicode without translation (or, depending on how you look at it, by
+implicitly assuming that the byte strings are in Latin-1). As perl assumes
+the C locale by default, upgrading a string to UTF-8 may change the
+meaning of its contents regarding character classes, case mapping, etc.
+This should probably emit a warning (at least).
+
+Introduce a new special block, UNITCHECK, which is run at the end of a
+compilation unit (module, file, eval(STRING) block). This will correspond to
+the Perl 6 CHECK. Perl 5's CHECK cannot be changed or removed because the
+O.pm/B.pm backend framework depends on it.
+
+Study the possibility of adding a new prototype character, C<_>, meaning
+"this argument defaults to $_".
+
+Make the peephole optimizer optional.
+
+Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
+
+Fix the bugs revealed by running the test suite with the C<-t> switch (via
+C<make test.taintwarn>).
+
+Make threads more robust.
+
+Make C<no 6> and C<no v6> work (opposite of C<use 5.005>, etc.).
+
+A test suite for the B module would be nice.
+
+A ponie.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl592delta.pod b/Master/tlpkg/tlperl/lib/pods/perl592delta.pod
new file mode 100644
index 00000000000..9648843d79e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl592delta.pod
@@ -0,0 +1,342 @@
+=head1 NAME
+
+perl592delta - what is new for perl v5.9.2
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.9.1 and the 5.9.2
+development releases. See L<perl590delta> and L<perl591delta> for the
+differences between 5.8.0 and 5.9.1.
+
+=head1 Incompatible Changes
+
+=head2 Packing and UTF-8 strings
+
+The semantics of pack() and unpack() regarding UTF-8-encoded data has been
+changed. Processing is now by default character per character instead of
+byte per byte on the underlying encoding. Notably, code that used things
+like C<pack("a*", $string)> to see through the encoding of string will now
+simply get back the original $string. Packed strings can also get upgraded
+during processing when you store upgraded characters. You can get the old
+behaviour by using C<use bytes>.
+
+To be consistent with pack(), the C<C0> in unpack() templates indicates
+that the data is to be processed in character mode, i.e. character by
+character; on the contrary, C<U0> in unpack() indicates UTF-8 mode, where
+the packed string is processed in its UTF-8-encoded Unicode form on a byte
+by byte basis. This is reversed with regard to perl 5.8.X.
+
+Moreover, C<C0> and C<U0> can also be used in pack() templates to specify
+respectively character and byte modes.
+
+C<C0> and C<U0> in the middle of a pack or unpack format now switch to the
+specified encoding mode, honoring parens grouping. Previously, parens were
+ignored.
+
+Also, there is a new pack() character format, C<W>, which is intended to
+replace the old C<C>. C<C> is kept for unsigned chars coded as bytes in
+the strings internal representation. C<W> represents unsigned (logical)
+character values, which can be greater than 255. It is therefore more
+robust when dealing with potentially UTF-8-encoded data (as C<C> will wrap
+values outside the range 0..255, and not respect the string encoding).
+
+In practice, that means that pack formats are now encoding-neutral, except
+C<C>.
+
+For consistency, C<A> in unpack() format now trims all Unicode whitespace
+from the end of the string. Before perl 5.9.2, it used to strip only the
+classical ASCII space characters.
+
+=head2 Miscellaneous
+
+The internal dump output has been improved, so that non-printable characters
+such as newline and backspace are output in C<\x> notation, rather than
+octal.
+
+The B<-C> option can no longer be used on the C<#!> line. It wasn't
+working there anyway.
+
+=head1 Core Enhancements
+
+=head2 Malloc wrapping
+
+Perl can now be built to detect attempts to assign pathologically large chunks
+of memory. Previously such assignments would suffer from integer wrap-around
+during size calculations causing a misallocation, which would crash perl, and
+could theoretically be used for "stack smashing" attacks. The wrapping
+defaults to enabled on platforms where we know it works (most AIX
+configurations, BSDi, Darwin, DEC OSF/1, FreeBSD, HP-UX, GNU Linux, OpenBSD,
+Solaris, VMS and most Win32 compilers) and defaults to disabled on other
+platforms.
+
+=head2 Unicode Character Database 4.0.1
+
+The copy of the Unicode Character Database included in Perl 5.9 has
+been updated to 4.0.1 from 4.0.0.
+
+=head2 suidperl less insecure
+
+Paul Szabo has analysed and patched C<suidperl> to remove existing known
+insecurities. Currently there are no known holes in C<suidperl>, but previous
+experience shows that we cannot be confident that these were the last. You may
+no longer invoke the set uid perl directly, so to preserve backwards
+compatibility with scripts that invoke #!/usr/bin/suidperl the only set uid
+binary is now C<sperl5.9.>I<n> (C<sperl5.9.2> for this release). C<suidperl>
+is installed as a hard link to C<perl>; both C<suidperl> and C<perl> will
+invoke C<sperl5.9.2> automatically the set uid binary, so this change should
+be completely transparent.
+
+For new projects the core perl team would strongly recommend that you use
+dedicated, single purpose security tools such as C<sudo> in preference to
+C<suidperl>.
+
+=head2 PERLIO_DEBUG
+
+The C<PERLIO_DEBUG> environment variable has no longer any effect for
+setuid scripts and for scripts run with B<-T>.
+
+Moreover, with a thread-enabled perl, using C<PERLIO_DEBUG> could lead to
+an internal buffer overflow. This has been fixed.
+
+=head2 Formats
+
+In addition to bug fixes, C<format>'s features have been enhanced. See
+L<perlform>.
+
+=head2 Unicode Character Classes
+
+Perl's regular expression engine now contains support for matching on the
+intersection of two Unicode character classes. You can also now refer to
+user-defined character classes from within other user defined character
+classes.
+
+=head2 Byte-order modifiers for pack() and unpack()
+
+There are two new byte-order modifiers, C<E<gt>> (big-endian) and C<E<lt>>
+(little-endian), that can be appended to most pack() and unpack() template
+characters and groups to force a certain byte-order for that type or group.
+See L<perlfunc/pack> and L<perlpacktut> for details.
+
+=head2 Byte count feature in pack()
+
+A new pack() template character, C<".">, returns the number of characters
+read so far.
+
+=head2 New variables
+
+A new variable, ${^RE_DEBUG_FLAGS}, controls what debug flags are in
+effect for the regular expression engine when running under C<use re
+"debug">. See L<re> for details.
+
+A new variable ${^UTF8LOCALE} indicates where a UTF-8 locale was detected
+by perl at startup.
+
+=head1 Modules and Pragmata
+
+=head2 New modules
+
+=over 4
+
+=item *
+
+C<encoding::warnings>, by Audrey Tang, is a module to emit warnings
+whenever an ASCII character string containing high-bit bytes is implicitly
+converted into UTF-8.
+
+=item *
+
+C<Module::CoreList>, by Richard Clamp, is a small handy module that tells
+you what versions of core modules ship with any versions of Perl 5. It
+comes with a command-line frontend, C<corelist>.
+
+=back
+
+=head2 Updated And Improved Modules and Pragmata
+
+Dual-lived modules have been updated to be kept up-to-date with respect to
+CPAN.
+
+The dual-lived modules which contain an C<_> in their version number are
+actually I<ahead> of the corresponding CPAN release.
+
+=over 4
+
+=item B::Concise
+
+C<B::Concise> was significantly improved.
+
+=item Socket
+
+There is experimental support for Linux abstract Unix domain sockets.
+
+=item Sys::Syslog
+
+C<syslog()> can now use numeric constants for facility names and priorities,
+in addition to strings.
+
+=item threads
+
+Detached threads are now also supported on Windows.
+
+=back
+
+=head1 Utility Changes
+
+=over 4
+
+=item *
+
+The C<corelist> utility is now installed with perl (see L</"New modules">
+above).
+
+=item *
+
+C<h2ph> and C<h2xs> have been made a bit more robust with regard to
+"modern" C code.
+
+=item *
+
+Several bugs have been fixed in C<find2perl>, regarding C<-exec> and
+C<-eval>. Also the options C<-path>, C<-ipath> and C<-iname> have been
+added.
+
+=item *
+
+The Perl debugger can now save all debugger commands for sourcing later;
+notably, it can now emulate stepping backwards, by restarting and
+rerunning all bar the last command from a saved command history.
+
+It can also display the parent inheritance tree of a given class.
+
+Perl has a new -dt command-line flag, which enables threads support in the
+debugger.
+
+=back
+
+=head1 Performance Enhancements
+
+=over 4
+
+=item *
+
+Unicode case mappings (C</i>, C<lc>, C<uc>, etc) are faster.
+
+=item *
+
+C<@a = sort @a> was optimized to do in-place sort. Likewise, C<reverse
+sort ...> is now optimized to sort in reverse, avoiding the generation of
+a temporary intermediate list.
+
+=item *
+
+Unnecessary assignments are optimised away in
+
+ my $s = undef;
+ my @a = ();
+ my %h = ();
+
+=item *
+
+C<map> in scalar context is now optimized.
+
+=item *
+
+The regexp engine now implements the trie optimization : it's able to
+factorize common prefixes and suffixes in regular expressions. A new
+special variable, ${^RE_TRIE_MAXBUF}, has been added to fine-tune this
+optimization.
+
+=back
+
+=head1 Installation and Configuration Improvements
+
+Run-time customization of @INC can be enabled by passing the
+C<-Dusesitecustomize> flag to configure. When enabled, this will make perl
+run F<$sitelibexp/sitecustomize.pl> before anything else. This script can
+then be set up to add additional entries to @INC.
+
+There is alpha support for relocatable @INC entries.
+
+Perl should build on Interix and on GNU/kFreeBSD.
+
+=head1 Selected Bug Fixes
+
+Most of those bugs were reported in the perl 5.8.x maintenance track.
+Notably, quite a few utf8 bugs were fixed, and several memory leaks were
+suppressed. The perl58Xdelta manpages have more details on them.
+
+Development-only bug fixes include :
+
+C<$Foo::_> was wrongly forced as C<$main::_>.
+
+=head1 New or Changed Diagnostics
+
+A new warning, C<!=~ should be !~>, is emitted to prevent this misspelling
+of the non-matching operator.
+
+The warning I<Newline in left-justified string> has been removed.
+
+The error I<Too late for "-T" option> has been reformulated to be more
+descriptive.
+
+There is a new compilation error, I<Illegal declaration of subroutine>,
+for an obscure case of syntax errors.
+
+The diagnostic output of Carp has been changed slightly, to add a space after
+the comma between arguments. This makes it much easier for tools such as
+web browsers to wrap it, but might confuse any automatic tools which perform
+detailed parsing of Carp output.
+
+C<perl -V> has several improvements, making it more useable from shell
+scripts to get the value of configuration variables. See L<perlrun> for
+details.
+
+=head1 Changed Internals
+
+The perl core has been refactored and reorganised in several places.
+In short, this release will not be binary compatible with any previous
+perl release.
+
+=head1 Known Problems
+
+For threaded builds, F<ext/threads/shared/t/wait.t> has been reported to
+fail some tests on HP-UX 10.20.
+
+Net::Ping might fail some tests on HP-UX 11.00 with the latest OS
+upgrades.
+
+F<t/io/dup.t>, F<t/io/open.t> and F<lib/ExtUtils/t/Constant.t> fail some
+tests on some BSD flavours.
+
+=head1 Plans for the next release
+
+The current plan for perl 5.9.3 is to add CPANPLUS as a core module.
+More regular expression optimizations are also in the works.
+
+It is planned to release a development version of perl more frequently,
+i.e. each time something major changes.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl593delta.pod b/Master/tlpkg/tlperl/lib/pods/perl593delta.pod
new file mode 100644
index 00000000000..6c8587aee9e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl593delta.pod
@@ -0,0 +1,549 @@
+=head1 NAME
+
+perl593delta - what is new for perl v5.9.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.9.2 and the 5.9.3
+development releases. See L<perl590delta>, L<perl591delta> and
+L<perl592delta> for the differences between 5.8.0 and 5.9.2.
+
+=head1 Incompatible Changes
+
+=head2 Parsing of C<-f _>
+
+The identifier C<_> is now forced to be a bareword after a filetest
+operator. This solves a number of misparsing issues when a global C<_>
+subroutine is defined.
+
+=head2 C<mkdir()>
+
+C<mkdir()> without arguments now defaults to C<$_>.
+
+=head2 Magic goto and eval
+
+The construct C<eval { goto &foo }> is now disallowed. (Note that the
+similar construct, but with C<eval("")> instead, was already forbidden.)
+
+=head2 C<$#> has been removed
+
+The deprecated C<$#> variable (output format for numbers) has been
+removed. A new warning, C<$# is no longer supported>, has been added.
+
+=head2 C<:unique>
+
+The C<:unique> attribute has been made a no-op, since its current
+implementation was fundamentally flawed and not threadsafe.
+
+=head2 Scoping of the C<sort> pragma
+
+The C<sort> pragma is now lexically scoped. Its effect used to be global.
+
+=head1 Core Enhancements
+
+=head2 The C<feature> pragma
+
+The C<feature> pragma is used to enable new syntax that would break Perl's
+backwards-compatibility with older releases of the language. It's a lexical
+pragma, like C<strict> or C<warnings>.
+
+Currently the following new features are available: C<switch> (adds a
+switch statement), C<~~> (adds a Perl 6-like smart match operator), C<say>
+(adds a C<say> built-in function), and C<err> (adds an C<err> keyword).
+Those features are described below.
+
+Note that C<err> low-precedence defined-or operator used to be enabled by
+default (although as a weak keyword, meaning that any function would
+override it). It's now only recognized when explicitly turned on (and is
+then a regular keyword).
+
+Those features, and the C<feature> pragma itself, have been contributed by
+Robin Houston.
+
+=head2 Switch and Smart Match operator
+
+Perl 5 now has a switch statement. It's available when C<use feature
+'switch'> is in effect. This feature introduces three new keywords,
+C<given>, C<when>, and C<default>:
+
+ given ($foo) {
+ when (/^abc/) { $abc = 1; }
+ when (/^def/) { $def = 1; }
+ when (/^xyz/) { $xyz = 1; }
+ default { $nothing = 1; }
+ }
+
+A more complete description of how Perl matches the switch variable
+against the C<when> conditions is given in L<perlsyn/"Switch statements">.
+
+This kind of match is called I<smart match>, and it's also possible to use
+it outside of switch statements, via the new C<~~> operator (enabled via
+the C<use feature '~~'> directive). See L<perlsyn/"Smart matching in
+detail">.
+
+=head2 C<say()>
+
+say() is a new built-in, only available when C<use feature 'say'> is in
+effect, that is similar to print(), but that implicitly appends a newline
+to the printed string. See L<perlfunc/say>.
+
+=head2 C<CLONE_SKIP()>
+
+Perl has now support for the C<CLONE_SKIP> special subroutine. Like
+C<CLONE>, C<CLONE_SKIP> is called once per package; however, it is called
+just before cloning starts, and in the context of the parent thread. If it
+returns a true value, then no objects of that class will be cloned. See
+L<perlmod> for details. (Contributed by Dave Mitchell.)
+
+=head2 C<${^CHILD_ERROR_NATIVE}>
+
+A new internal variable, C<${^CHILD_ERROR_NATIVE}>, gives the native
+status returned by the last pipe close, backtick command, successful call
+to wait() or waitpid(), or from the system() operator. See L<perlrun> for
+details. (Contributed by Gisle Aas.)
+
+=head2 Assertions
+
+The support for assertions, introduced in perl 5.9.0, has been improved.
+The syntax for the C<-A> command-line switch has changed; it now accepts
+an optional module name, defaulting to C<assertions::activate>. See
+L<assertions> and L<perlrun>. (Contributed by Salvador Fandiño García.)
+
+=head2 Unicode Character Database 4.1.0
+
+The copy of the Unicode Character Database included in Perl 5.9 has
+been updated to 4.1.0.
+
+=head2 C<no VERSION>
+
+You can now use C<no> followed by a version number to specify that you
+want to use a version of perl older than the specified one.
+
+=head2 Recursive sort subs
+
+You can now use recursive subroutines with sort(), thanks to Robin Houston.
+
+=head2 Effect of pragmas in eval
+
+The compile-time value of the C<%^H> hint variable can now propagate into
+eval("")uated code. This makes it more useful to implement lexical
+pragmas.
+
+As a side-effect of this, the overloaded-ness of constants now propagates
+into eval("").
+
+=head2 New B<-E> command-line switch
+
+B<-E> is equivalent to B<-e>, but it implicitly enables all
+optional features (like C<use feature ":5.10">).
+
+=head2 C<chdir>, C<chmod> and C<chown> on filehandles
+
+C<chdir>, C<chmod> and C<chown> can now work on filehandles as well as
+filenames, if the system supports respectively C<fchdir>, C<fchmod> and
+C<fchown>, thanks to a patch provided by Gisle Aas.
+
+=head2 OS groups
+
+C<$(> and C<$)> now return groups in the order where the OS returns them,
+thanks to Gisle Aas. This wasn't previously the case.
+
+=head1 Modules and Pragmata
+
+=head2 New Core Modules
+
+=over 4
+
+=item *
+
+A new pragma, C<feature>, has been added; see above in L</"Core
+Enhancements">.
+
+=item *
+
+C<assertions::compat>, also available on CPAN, allows the use of assertions on
+perl versions prior to 5.9.0 (that is the first one to natively support
+them).
+
+=item *
+
+C<Math::BigInt::FastCalc> is an XS-enabled, and thus faster, version of
+C<Math::BigInt::Calc>.
+
+=item *
+
+C<Compress::Zlib> is an interface to the zlib compression library. It
+comes with a bundled version of zlib, so having a working zlib is not a
+prerequisite to install it. It's used by C<Archive::Tar> (see below).
+
+=item *
+
+C<IO::Zlib> is an C<IO::>-style interface to C<Compress::Zlib>.
+
+=item *
+
+C<Archive::Tar> is a module to manipulate C<tar> archives.
+
+=item *
+
+C<Digest::SHA> is a module used to calculate many types of SHA digests,
+has been included for SHA support in the CPAN module.
+
+=item *
+
+C<ExtUtils::CBuilder> and C<ExtUtils::ParseXS> have been added.
+
+=back
+
+=head1 Utility Changes
+
+=head2 C<ptar>
+
+C<ptar> is a pure perl implementation of C<tar>, that comes with
+C<Archive::Tar>.
+
+=head2 C<ptardiff>
+
+C<ptardiff> is a small script used to generate a diff between the contents
+of a tar archive and a directory tree. Like C<ptar>, it comes with
+C<Archive::Tar>.
+
+=head2 C<shasum>
+
+This command-line utility, used to print or to check SHA digests, comes
+with the new C<Digest::SHA> module.
+
+=head2 C<h2xs> enhancements
+
+C<h2xs> implements a new option C<--use-xsloader> to force use of
+C<XSLoader> even in backwards compatible modules.
+
+The handling of authors' names that had apostrophes has been fixed.
+
+Any enums with negative values are now skipped.
+
+=head2 C<perlivp> enhancements
+
+C<perlivp> no longer checks for F<*.ph> files by default. Use the new C<-a>
+option to run I<all> tests.
+
+=head1 Documentation
+
+=head2 Perl Glossary
+
+The L<perlglossary> manpage is a glossary of terms used in the Perl
+documentation, technical and otherwise, kindly provided by O'Reilly Media,
+Inc.
+
+L<perltodo> now lists a rough roadmap to Perl 5.10.
+
+=head1 Performance Enhancements
+
+=head2 XS-assisted SWASHGET
+
+Some pure-perl code that perl was using to retrieve Unicode properties and
+transliteration mappings has been reimplemented in XS.
+
+=head2 Constant subroutines
+
+The interpreter internals now support a far more memory efficient form of
+inlineable constants. Storing a reference to a constant value in a symbol
+table is equivalent to a full typeglob referencing a constant subroutine,
+but using about 400 bytes less memory. This proxy constant subroutine is
+automatically upgraded to a real typeglob with subroutine if necessary.
+The approach taken is analogous to the existing space optimisation for
+subroutine stub declarations, which are stored as plain scalars in place
+of the full typeglob.
+
+Several of the core modules have been converted to use this feature for
+their system dependent constants - as a result C<use POSIX;> now takes about
+200K less memory.
+
+=head2 C<PERL_DONT_CREATE_GVSV>
+
+The new compilation flag C<PERL_DONT_CREATE_GVSV>, introduced as an option
+in perl 5.8.8, is turned on by default in perl 5.9.3. It prevents perl
+from creating an empty scalar with every new typeglob. See L<perl589delta>
+for details.
+
+=head2 Weak references are cheaper
+
+Weak reference creation is now I<O(1)> rather than I<O(n)>, courtesy of
+Nicholas Clark. Weak reference deletion remains I<O(n)>, but if deletion only
+happens at program exit, it may be skipped completely.
+
+=head2 sort() enhancements
+
+Salvador Fandiño provided improvements to reduce the memory usage of C<sort>
+and to speed up some cases.
+
+=head1 Installation and Configuration Improvements
+
+=head2 Compilation improvements
+
+Parallel makes should work properly now, although there may still be problems
+if C<make test> is instructed to run in parallel.
+
+Building with Borland's compilers on Win32 should work more smoothly. In
+particular Steve Hay has worked to side step many warnings emitted by their
+compilers and at least one C compiler internal error.
+
+Perl extensions on Windows now can be statically built into the Perl DLL,
+thanks to a work by Vadim Konovalov.
+
+=head2 New Or Improved Platforms
+
+Perl is being ported to Symbian OS. See L<perlsymbian> for more
+information.
+
+The VMS port has been improved. See L<perlvms>.
+
+DynaLoader::dl_unload_file() now works on Windows.
+
+Portability of Perl on various recent compilers on Windows has been
+improved (Borland C++, Visual C++ 7.0).
+
+=head2 New probes
+
+C<Configure> will now detect C<clearenv> and C<unsetenv>, thanks to a
+patch from Alan Burlison. It will also probe for C<futimes> (and use it
+internally if available), and whether C<sprintf> correctly returns the
+length of the formatted string.
+
+=head2 Module auxiliary files
+
+README files and changelogs for CPAN modules bundled with perl are no
+longer installed.
+
+=head1 Selected Bug Fixes
+
+=head2 C<defined $$x>
+
+C<use strict "refs"> was ignoring taking a hard reference in an argument
+to defined(), as in :
+
+ use strict "refs";
+ my $x = "foo";
+ if (defined $$x) {...}
+
+This now correctly produces the run-time error C<Can't use string as a
+SCALAR ref while "strict refs" in use>. (However, C<defined @$foo> and
+C<defined %$foo> are still allowed. Those constructs are discouraged
+anyway.)
+
+=head2 Calling CORE::require()
+
+CORE::require() and CORE::do() were always parsed as require() and do()
+when they were overridden. This is now fixed.
+
+=head2 Subscripts of slices
+
+You can now use a non-arrowed form for chained subscripts after a list
+slice, like in:
+
+ ({foo => "bar"})[0]{foo}
+
+This used to be a syntax error; a C<< -> >> was required.
+
+=head2 Remove over-optimisation
+
+Perl 5.9.2 introduced a change so that assignments of C<undef> to a
+scalar, or of an empty list to an array or a hash, were optimised out. As
+this could cause problems when C<goto> jumps were involved, this change
+was backed out.
+
+=head2 sprintf() fixes
+
+Using the sprintf() function with some formats could lead to a buffer
+overflow in some specific cases. This has been fixed, along with several
+other bugs, notably in bounds checking.
+
+In related fixes, it was possible for badly written code that did not follow
+the documentation of C<Sys::Syslog> to have formatting vulnerabilities.
+C<Sys::Syslog> has been changed to protect people from poor quality third
+party code.
+
+=head2 no warnings 'category' works correctly with -w
+
+Previously when running with warnings enabled globally via C<-w>, selective
+disabling of specific warning categories would actually turn off all warnings.
+This is now fixed; now C<no warnings 'io';> will only turn off warnings in the
+C<io> class. Previously it would erroneously turn off all warnings.
+
+=head2 Smaller fixes
+
+=over 4
+
+=item *
+
+C<FindBin> now works better with directories where access rights are more
+restrictive than usual.
+
+=item *
+
+Several memory leaks in ithreads were closed. Also, ithreads were made
+less memory-intensive.
+
+=item *
+
+Trailing spaces are now trimmed from C<$!> and C<$^E>.
+
+=item *
+
+Operations that require perl to read a process's list of groups, such as reads
+of C<$(> and C<$)>, now dynamically allocate memory rather than using a
+fixed sized array. The fixed size array could cause C stack exhaustion on
+systems configured to use large numbers of groups.
+
+=item *
+
+C<PerlIO::scalar> now works better with non-default C<$/> settings.
+
+=item *
+
+The C<x> repetition operator is now able to operate on C<qw//> lists. This
+used to raise a syntax error.
+
+=item *
+
+The debugger now traces correctly execution in eval("")uated code that
+contains #line directives.
+
+=item *
+
+The value of the C<open> pragma is no longer ignored for three-argument
+opens.
+
+=item *
+
+Perl will now use the C library calls C<unsetenv> and C<clearenv> if present
+to delete keys from C<%ENV> and delete C<%ENV> entirely, thanks to a patch
+from Alan Burlison.
+
+=back
+
+=head2 More Unicode Fixes
+
+=over 4
+
+=item *
+
+chr() on a negative value now gives C<\x{FFFD}>, the Unicode replacement
+character, unless when the C<bytes> pragma is in effect, where the low
+eight bytes of the value are used.
+
+=item *
+
+Some case insensitive matches between UTF-8 encoded data and 8 bit regexps,
+and vice versa, could give malformed character warnings. These have been
+fixed by Dave Mitchell and Yves Orton.
+
+=item *
+
+C<lcfirst> and C<ucfirst> could corrupt the string for certain cases where
+the length UTF-8 encoding of the string in lower case, upper case or title
+case differed. This was fixed by Nicholas Clark.
+
+=back
+
+=head1 New or Changed Diagnostics
+
+=head2 Attempt to set length of freed array
+
+This is a new warning, produced in situations like the following one:
+
+ $r = do {my @a; \$#a};
+ $$r = 503;
+
+=head2 Non-string passed as bitmask
+
+This is a new warning, produced when number has been passed as a argument to
+select(), instead of a bitmask.
+
+ # Wrong, will now warn
+ $rin = fileno(STDIN);
+ ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout);
+
+ # Should be
+ $rin = '';
+ vec($rin,fileno(STDIN),1) = 1;
+ ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout);
+
+=head2 Search pattern not terminated or ternary operator parsed as search pattern
+
+This syntax error indicates that the lexer couldn't find the final
+delimiter of a C<?PATTERN?> construct. Mentioning the ternary operator in
+this error message makes syntax diagnostic easier.
+
+=head2 "%s" variable %s masks earlier declaration
+
+This warning is now emitted in more consistent cases; in short, when one
+of the declarations involved is a C<my> variable:
+
+ my $x; my $x; # warns
+ my $x; our $x; # warns
+ our $x; my $x; # warns
+
+On the other hand, the following:
+
+ our $x; our $x;
+
+now gives a C<"our" variable %s redeclared> warning.
+
+=head2 readdir()/closedir()/etc. attempted on invalid dirhandle
+
+These new warnings are now emitted when a dirhandle is used but is
+either closed or not really a dirhandle.
+
+=head1 Changed Internals
+
+In general, the source code of perl has been refactored, tied up, and
+optimized in many places. Also, memory management and allocation has been
+improved in a couple of points.
+
+Andy Lester supplied many improvements to determine which function
+parameters and local variables could actually be declared C<const> to the C
+compiler. Steve Peters provided new C<*_set> macros and reworked the core to
+use these rather than assigning to macros in LVALUE context.
+
+Dave Mitchell improved the lexer debugging output under C<-DT>.
+
+A new file, F<mathoms.c>, has been added. It contains functions that are
+no longer used in the perl core, but that remain available for binary or
+source compatibility reasons. However, those functions will not be
+compiled in if you add C<-DNO_MATHOMS> in the compiler flags.
+
+The C<AvFLAGS> macro has been removed.
+
+The C<av_*()> functions, used to manipulate arrays, no longer accept null
+C<AV*> parameters.
+
+=head2 B:: modules inheritance changed
+
+The inheritance hierarchy of C<B::> modules has changed; C<B::NV> now
+inherits from C<B::SV> (it used to inherit from C<B::IV>).
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl594delta.pod b/Master/tlpkg/tlperl/lib/pods/perl594delta.pod
new file mode 100644
index 00000000000..aa4358bc504
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl594delta.pod
@@ -0,0 +1,382 @@
+=head1 NAME
+
+perl594delta - what is new for perl v5.9.4
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.9.3 and the 5.9.4
+development releases. See L<perl590delta>, L<perl591delta>, L<perl592delta>
+and L<perl593delta> for the differences between 5.8.0 and 5.9.3.
+
+=head1 Incompatible Changes
+
+=head2 chdir FOO
+
+A bareword argument to chdir() is now recognized as a file handle.
+Earlier releases interpreted the bareword as a directory name.
+(Gisle Aas)
+
+=head2 Handling of pmc files
+
+An old feature of perl was that before C<require> or C<use> look for a
+file with a F<.pm> extension, they will first look for a similar filename
+with a F<.pmc> extension. If this file is found, it will be loaded in
+place of any potentially existing file ending in a F<.pm> extension.
+
+Previously, F<.pmc> files were loaded only if more recent than the
+matching F<.pm> file. Starting with 5.9.4, they'll be always loaded if
+they exist. (This trick is used by Pugs.)
+
+=head2 @- and @+ in patterns
+
+The special arrays C<@-> and C<@+> are no longer interpolated in regular
+expressions. (Sadahiro Tomoyuki)
+
+=head2 $AUTOLOAD can now be tainted
+
+If you call a subroutine by a tainted name, and if it defers to an
+AUTOLOAD function, then $AUTOLOAD will be (correctly) tainted.
+(Rick Delaney)
+
+=head1 Core Enhancements
+
+=head2 state() variables
+
+A new class of variables has been introduced. State variables are similar
+to C<my> variables, but are declared with the C<state> keyword in place of
+C<my>. They're visible only in their lexical scope, but their value is
+persistent: unlike C<my> variables, they're not undefined at scope entry,
+but retain their previous value. (Rafael Garcia-Suarez)
+
+To use state variables, one needs to enable them by using
+
+ use feature "state";
+
+or by using the C<-E> command-line switch in one-liners.
+
+See L<perlsub/"Persistent variables via state()">.
+
+=head2 UNIVERSAL::DOES()
+
+The C<UNIVERSAL> class has a new method, C<DOES()>. It has been added to
+solve semantic problems with the C<isa()> method. C<isa()> checks for
+inheritance, while C<DOES()> has been designed to be overridden when
+module authors use other types of relations between classes (in addition
+to inheritance). (chromatic)
+
+See L<< UNIVERSAL/"$obj->DOES( ROLE )" >>.
+
+=head2 Exceptions in constant folding
+
+The constant folding routine is now wrapped in an exception handler, and
+if folding throws an exception (such as attempting to evaluate 0/0), perl
+now retains the current optree, rather than aborting the whole program.
+(Nicholas Clark, Dave Mitchell)
+
+=head2 Source filters in @INC
+
+It's possible to enhance the mechanism of subroutine hooks in @INC by
+adding a source filter on top of the filehandle opened and returned by the
+hook. This feature was planned a long time ago, but wasn't quite working
+until now. See L<perlfunc/require> for details. (Nicholas Clark)
+
+=head2 MAD
+
+MAD, which stands for I<Misc Attribute Decoration>, is a
+still-in-development work leading to a Perl 5 to Perl 6 converter. To
+enable it, it's necessary to pass the argument C<-Dmad> to Configure. The
+obtained perl isn't binary compatible with a regular perl 5.9.4, and has
+space and speed penalties; moreover not all regression tests still pass
+with it. (Larry Wall, Nicholas Clark)
+
+=head1 Modules and Pragmas
+
+=over 4
+
+=item *
+
+C<encoding::warnings> is now a lexical pragma. (Although on older perls,
+which don't have support for lexical pragmas, it keeps its global
+behaviour.) (Audrey Tang)
+
+=item *
+
+C<threads> is now a dual-life module, also available on CPAN. It has been
+expanded in many ways. A kill() method is available for thread signalling.
+One can get thread status, or the list of running or joinable threads.
+
+A new C<< threads->exit() >> method is used to exit from the application
+(this is the default for the main thread) or from the current thread only
+(this is the default for all other threads). On the other hand, the exit()
+built-in now always causes the whole application to terminate. (Jerry
+D. Hedden)
+
+=back
+
+=head2 New Core Modules
+
+=over 4
+
+=item *
+
+C<Hash::Util::FieldHash>, by Anno Siegel, has been added. This module
+provides support for I<field hashes>: hashes that maintain an association
+of a reference with a value, in a thread-safe garbage-collected way.
+Such hashes are useful to implement inside-out objects.
+
+=item *
+
+C<Module::Build>, by Ken Williams, has been added. It's an alternative to
+C<ExtUtils::MakeMaker> to build and install perl modules.
+
+=item *
+
+C<Module::Load>, by Jos Boumans, has been added. It provides a single
+interface to load Perl modules and F<.pl> files.
+
+=item *
+
+C<Module::Loaded>, by Jos Boumans, has been added. It's used to mark
+modules as loaded or unloaded.
+
+=item *
+
+C<Package::Constants>, by Jos Boumans, has been added. It's a simple
+helper to list all constants declared in a given package.
+
+=item *
+
+C<Win32API::File>, by Tye McQueen, has been added (for Windows builds).
+This module provides low-level access to Win32 system API calls for
+files/dirs.
+
+=back
+
+=head1 Utility Changes
+
+=head2 config_data
+
+C<config_data> is a new utility that comes with C<Module::Build>. It
+provides a command-line interface to the configuration of Perl modules
+that use Module::Build's framework of configurability (that is,
+C<*::ConfigData> modules that contain local configuration information for
+their parent modules.)
+
+=head1 Documentation
+
+=head2 New manpage, perlpragma
+
+The L<perlpragma> manpage documents how to write one's own lexical
+pragmas in pure Perl (something that is possible starting with 5.9.4).
+
+=head2 New manpage, perlreguts
+
+The L<perlreguts> manpage, courtesy of Yves Orton, describes internals of the
+Perl regular expression engine.
+
+=head2 New manpage, perlunitut
+
+The L<perlunitut> manpage is an tutorial for programming with Unicode and
+string encodings in Perl, courtesy of Juerd Waalboer.
+
+=head1 Performance Enhancements
+
+=head2 Memory optimisations
+
+Several internal data structures (typeglobs, GVs, CVs, formats) have been
+restructured to use less memory. (Nicholas Clark)
+
+=head2 UTF-8 cache optimisation
+
+The UTF-8 caching code is now more efficient, and used more often.
+(Nicholas Clark)
+
+=head2 Regular expressions
+
+=over 4
+
+=item Engine de-recursivised
+
+The regular expression engine is no longer recursive, meaning that
+patterns that used to overflow the stack will either die with useful
+explanations, or run to completion, which, since they were able to blow
+the stack before, will likely take a very long time to happen. If you were
+experiencing the occasional stack overflow (or segfault) and upgrade to
+discover that now perl apparently hangs instead, look for a degenerate
+regex. (Dave Mitchell)
+
+=item Single char char-classes treated as literals
+
+Classes of a single character are now treated the same as if the character
+had been used as a literal, meaning that code that uses char-classes as an
+escaping mechanism will see a speedup. (Yves Orton)
+
+=item Trie optimisation of literal string alternations
+
+Alternations, where possible, are optimised into more efficient matching
+structures. String literal alternations are merged into a trie and are
+matched simultaneously. This means that instead of O(N) time for matching
+N alternations at a given point the new code performs in O(1) time. (Yves
+Orton)
+
+B<Note:> Much code exists that works around perl's historic poor
+performance on alternations. Often the tricks used to do so will disable
+the new optimisations. Hopefully the utility modules used for this purpose
+will be educated about these new optimisations by the time 5.10 is
+released.
+
+=item Aho-Corasick start-point optimisation
+
+When a pattern starts with a trie-able alternation and there aren't
+better optimisations available the regex engine will use Aho-Corasick
+matching to find the start point. (Yves Orton)
+
+=back
+
+=head2 Sloppy stat on Windows
+
+On Windows, perl's stat() function normally opens the file to determine
+the link count and update attributes that may have been changed through
+hard links. Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up
+stat() by not performing this operation. (Jan Dubois)
+
+=head1 Installation and Configuration Improvements
+
+=head2 Relocatable installations
+
+There is now Configure support for creating a relocatable perl tree. If
+you Configure with C<-Duserelocatableinc>, then the paths in @INC (and
+everything else in %Config) can be optionally located via the path of the
+perl executable.
+
+That means that, if the string C<".../"> is found at the start of any
+path, it's substituted with the directory of $^X. So, the relocation can
+be configured on a per-directory basis, although the default with
+C<-Duserelocatableinc> is that everything is relocated. The initial
+install is done to the original configured prefix.
+
+=head2 Ports
+
+Many improvements have been made towards making Perl work correctly on
+z/OS.
+
+Perl has been reported to work on DragonFlyBSD.
+
+=head2 Compilation improvements
+
+All F<ppport.h> files in the XS modules bundled with perl are now
+autogenerated at build time. (Marcus Holland-Moritz)
+
+=head2 New probes
+
+The configuration process now detects whether strlcat() and strlcpy() are
+available. When they are not available, perl's own version is used (from
+Russ Allbery's public domain implementation). Various places in the perl
+interpreter now use them. (Steve Peters)
+
+=head2 Windows build improvements
+
+=over 4
+
+=item Building XS extensions
+
+Support for building XS extension modules with the free MinGW compiler has
+been improved in the case where perl itself was built with the Microsoft
+VC++ compiler. (ActiveState)
+
+=item Support for 64-bit compiler
+
+Support for building perl with Microsoft's 64-bit compiler has been
+improved. (ActiveState)
+
+=back
+
+=head1 Selected Bug Fixes
+
+=head2 PERL5SHELL and tainting
+
+On Windows, the PERL5SHELL environment variable is now checked for
+taintedness. (Rafael Garcia-Suarez)
+
+=head2 Using *FILE{IO}
+
+C<stat()> and C<-X> filetests now treat *FILE{IO} filehandles like *FILE
+filehandles. (Steve Peters)
+
+=head2 Overloading and reblessing
+
+Overloading now works when references are reblessed into another class.
+Internally, this has been implemented by moving the flag for "overloading"
+from the reference to the referent, which logically is where it should
+always have been. (Nicholas Clark)
+
+=head2 Overloading and UTF-8
+
+A few bugs related to UTF-8 handling with objects that have
+stringification overloaded have been fixed. (Nicholas Clark)
+
+=head2 eval memory leaks fixed
+
+Traditionally, C<eval 'syntax error'> has leaked badly. Many (but not all)
+of these leaks have now been eliminated or reduced. (Dave Mitchell)
+
+=head2 Random device on Windows
+
+In previous versions, perl would read the file F</dev/urandom> if it
+existed when seeding its random number generator. That file is unlikely
+to exist on Windows, and if it did would probably not contain appropriate
+data, so perl no longer tries to read it on Windows. (Alex Davies)
+
+=head1 New or Changed Diagnostics
+
+=over 4
+
+=item State variable %s will be reinitialized
+
+One can assign initial values to state variables, but not when they're
+declared as a sub-part of a list assignment. See L<perldiag>.
+
+=back
+
+=head1 Changed Internals
+
+A new file, F<mathoms.c>, contains functions that aren't used anymore in
+the perl core, but remain around because modules out there might
+still use them. They come from a factorization effort: for example, many
+PP functions are now shared for several ops.
+
+The implementation of the special variables $^H and %^H has changed, to
+allow implementing lexical pragmas in pure perl.
+
+=head1 Known Problems
+
+One warning test (number 263 in F<lib/warnings.t>) fails under UTF-8
+locales.
+
+Bytecode tests fail under several platforms. We are considering removing
+support for byteloader and compiler before the 5.10.0 release.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/rt3/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perl595delta.pod b/Master/tlpkg/tlperl/lib/pods/perl595delta.pod
new file mode 100644
index 00000000000..246b2cc7478
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perl595delta.pod
@@ -0,0 +1,587 @@
+=head1 NAME
+
+perl595delta - what is new for perl v5.9.5
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.9.4 and the 5.9.5
+development releases. See L<perl590delta>, L<perl591delta>,
+L<perl592delta>, L<perl593delta> and L<perl594delta> for the differences
+between 5.8.0 and 5.9.4.
+
+=head1 Incompatible Changes
+
+=head2 Tainting and printf
+
+When perl is run under taint mode, C<printf()> and C<sprintf()> will now
+reject any tainted format argument. (Rafael Garcia-Suarez)
+
+=head2 undef and signal handlers
+
+Undefining or deleting a signal handler via C<undef $SIG{FOO}> is now
+equivalent to setting it to C<'DEFAULT'>. (Rafael)
+
+=head2 strictures and array/hash dereferencing in defined()
+
+C<defined @$foo> and C<defined %$bar> are now subject to C<strict 'refs'>
+(that is, C<$foo> and C<$bar> shall be proper references there.)
+(Nicholas Clark)
+
+(However, C<defined(@foo)> and C<defined(%bar)> are discouraged constructs
+anyway.)
+
+=head2 C<(?p{})> has been removed
+
+The regular expression construct C<(?p{})>, which was deprecated in perl
+5.8, has been removed. Use C<(??{})> instead. (Rafael)
+
+=head2 Pseudo-hashes have been removed
+
+Support for pseudo-hashes has been removed from Perl 5.9. (The C<fields>
+pragma remains here, but uses an alternate implementation.)
+
+=head2 Removal of the bytecode compiler and of perlcc
+
+C<perlcc>, the byteloader and the supporting modules (B::C, B::CC,
+B::Bytecode, etc.) are no longer distributed with the perl sources. Those
+experimental tools have never worked reliably, and, due to the lack of
+volunteers to keep them in line with the perl interpreter developments, it
+was decided to remove them instead of shipping a broken version of those.
+The last version of those modules can be found with perl 5.9.4.
+
+However the B compiler framework stays supported in the perl core, as with
+the more useful modules it has permitted (among others, B::Deparse and
+B::Concise).
+
+=head2 Removal of the JPL
+
+The JPL (Java-Perl Linguo) has been removed from the perl sources tarball.
+
+=head2 Recursive inheritance detected earlier
+
+Perl will now immediately throw an exception if you modify any package's
+C<@ISA> in such a way that it would cause recursive inheritance.
+
+Previously, the exception would not occur until Perl attempted to make
+use of the recursive inheritance while resolving a method or doing a
+C<$foo-E<gt>isa($bar)> lookup.
+
+=head1 Core Enhancements
+
+=head2 Regular expressions
+
+=over 4
+
+=item Recursive Patterns
+
+It is now possible to write recursive patterns without using the C<(??{})>
+construct. This new way is more efficient, and in many cases easier to
+read.
+
+Each capturing parenthesis can now be treated as an independent pattern
+that can be entered by using the C<(?PARNO)> syntax (C<PARNO> standing for
+"parenthesis number"). For example, the following pattern will match
+nested balanced angle brackets:
+
+ /
+ ^ # start of line
+ ( # start capture buffer 1
+ < # match an opening angle bracket
+ (?: # match one of:
+ (?> # don't backtrack over the inside of this group
+ [^<>]+ # one or more non angle brackets
+ ) # end non backtracking group
+ | # ... or ...
+ (?1) # recurse to bracket 1 and try it again
+ )* # 0 or more times.
+ > # match a closing angle bracket
+ ) # end capture buffer one
+ $ # end of line
+ /x
+
+Note, users experienced with PCRE will find that the Perl implementation
+of this feature differs from the PCRE one in that it is possible to
+backtrack into a recursed pattern, whereas in PCRE the recursion is
+atomic or "possessive" in nature. (Yves Orton)
+
+=item Named Capture Buffers
+
+It is now possible to name capturing parenthesis in a pattern and refer to
+the captured contents by name. The naming syntax is C<< (?<NAME>....) >>.
+It's possible to backreference to a named buffer with the C<< \k<NAME> >>
+syntax. In code, the new magical hashes C<%+> and C<%-> can be used to
+access the contents of the capture buffers.
+
+Thus, to replace all doubled chars, one could write
+
+ s/(?<letter>.)\k<letter>/$+{letter}/g
+
+Only buffers with defined contents will be "visible" in the C<%+> hash, so
+it's possible to do something like
+
+ foreach my $name (keys %+) {
+ print "content of buffer '$name' is $+{$name}\n";
+ }
+
+The C<%-> hash is a bit more complete, since it will contain array refs
+holding values from all capture buffers similarly named, if there should
+be many of them.
+
+C<%+> and C<%-> are implemented as tied hashes through the new module
+C<Tie::Hash::NamedCapture>.
+
+Users exposed to the .NET regex engine will find that the perl
+implementation differs in that the numerical ordering of the buffers
+is sequential, and not "unnamed first, then named". Thus in the pattern
+
+ /(A)(?<B>B)(C)(?<D>D)/
+
+$1 will be 'A', $2 will be 'B', $3 will be 'C' and $4 will be 'D' and not
+$1 is 'A', $2 is 'C' and $3 is 'B' and $4 is 'D' that a .NET programmer
+would expect. This is considered a feature. :-) (Yves Orton)
+
+=item Possessive Quantifiers
+
+Perl now supports the "possessive quantifier" syntax of the "atomic match"
+pattern. Basically a possessive quantifier matches as much as it can and never
+gives any back. Thus it can be used to control backtracking. The syntax is
+similar to non-greedy matching, except instead of using a '?' as the modifier
+the '+' is used. Thus C<?+>, C<*+>, C<++>, C<{min,max}+> are now legal
+quantifiers. (Yves Orton)
+
+=item Backtracking control verbs
+
+The regex engine now supports a number of special-purpose backtrack
+control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT), (*FAIL)
+and (*ACCEPT). See L<perlre> for their descriptions. (Yves Orton)
+
+=item Relative backreferences
+
+A new syntax C<\g{N}> or C<\gN> where "N" is a decimal integer allows a
+safer form of back-reference notation as well as allowing relative
+backreferences. This should make it easier to generate and embed patterns
+that contain backreferences. See L<perlre/"Capture buffers">. (Yves Orton)
+
+=item C<\K> escape
+
+The functionality of Jeff Pinyan's module Regexp::Keep has been added to
+the core. You can now use in regular expressions the special escape C<\K>
+as a way to do something like floating length positive lookbehind. It is
+also useful in substitutions like:
+
+ s/(foo)bar/$1/g
+
+that can now be converted to
+
+ s/foo\Kbar//g
+
+which is much more efficient. (Yves Orton)
+
+=item Vertical and horizontal whitespace, and linebreak
+
+Regular expressions now recognize the C<\v> and C<\h> escapes, that match
+vertical and horizontal whitespace, respectively. C<\V> and C<\H>
+logically match their complements.
+
+C<\R> matches a generic linebreak, that is, vertical whitespace, plus
+the multi-character sequence C<"\x0D\x0A">.
+
+=back
+
+=head2 The C<_> prototype
+
+A new prototype character has been added. C<_> is equivalent to C<$> (it
+denotes a scalar), but defaults to C<$_> if the corresponding argument
+isn't supplied. Due to the optional nature of the argument, you can only
+use it at the end of a prototype, or before a semicolon.
+
+This has a small incompatible consequence: the prototype() function has
+been adjusted to return C<_> for some built-ins in appropriate cases (for
+example, C<prototype('CORE::rmdir')>). (Rafael)
+
+=head2 UNITCHECK blocks
+
+C<UNITCHECK>, a new special code block has been introduced, in addition to
+C<BEGIN>, C<CHECK>, C<INIT> and C<END>.
+
+C<CHECK> and C<INIT> blocks, while useful for some specialized purposes,
+are always executed at the transition between the compilation and the
+execution of the main program, and thus are useless whenever code is
+loaded at runtime. On the other hand, C<UNITCHECK> blocks are executed
+just after the unit which defined them has been compiled. See L<perlmod>
+for more information. (Alex Gough)
+
+=head2 readpipe() is now overridable
+
+The built-in function readpipe() is now overridable. Overriding it permits
+also to override its operator counterpart, C<qx//> (a.k.a. C<``>).
+Moreover, it now defaults to C<$_> if no argument is provided. (Rafael)
+
+=head2 default argument for readline()
+
+readline() now defaults to C<*ARGV> if no argument is provided. (Rafael)
+
+=head2 UCD 5.0.0
+
+The copy of the Unicode Character Database included in Perl 5.9 has
+been updated to version 5.0.0.
+
+=head2 Smart match
+
+The smart match operator (C<~~>) is now available by default (you don't
+need to enable it with C<use feature> any longer). (Michael G Schwern)
+
+=head2 Implicit loading of C<feature>
+
+The C<feature> pragma is now implicitly loaded when you require a minimal
+perl version (with the C<use VERSION> construct) greater than, or equal
+to, 5.9.5.
+
+=head1 Modules and Pragmas
+
+=head2 New Pragma, C<mro>
+
+A new pragma, C<mro> (for Method Resolution Order) has been added. It
+permits to switch, on a per-class basis, the algorithm that perl uses to
+find inherited methods in case of a multiple inheritance hierarchy. The
+default MRO hasn't changed (DFS, for Depth First Search). Another MRO is
+available: the C3 algorithm. See L<mro> for more information.
+(Brandon Black)
+
+Note that, due to changes in the implementation of class hierarchy search,
+code that used to undef the C<*ISA> glob will most probably break. Anyway,
+undef'ing C<*ISA> had the side-effect of removing the magic on the @ISA
+array and should not have been done in the first place.
+
+=head2 bignum, bigint, bigrat
+
+The three numeric pragmas C<bignum>, C<bigint> and C<bigrat> are now
+lexically scoped. (Tels)
+
+=head2 Math::BigInt/Math::BigFloat
+
+Many bugs have been fixed; noteworthy are comparisons with NaN, which
+no longer warn about undef values.
+
+The following things are new:
+
+=over 4
+
+=item config()
+
+The config() method now also supports the calling-style
+C<< config('lib') >> in addition to C<< config()->{'lib'} >>.
+
+=item import()
+
+Upon import, using C<< lib => 'Foo' >> now warns if the low-level library
+cannot be found. To suppress the warning, you can use C<< try => 'Foo' >>
+instead. To convert the warning into a die, use C<< only => 'Foo' >>
+instead.
+
+=item roundmode common
+
+A rounding mode of C<common> is now supported.
+
+=back
+
+Also, support for the following methods has been added:
+
+=over 4
+
+=item bpi(), bcos(), bsin(), batan(), batan2()
+
+=item bmuladd()
+
+=item bexp(), bnok()
+
+=item from_hex(), from_oct(), and from_bin()
+
+=item as_oct()
+
+=back
+
+In addition, the default math-backend (Calc (Perl) and FastCalc (XS)) now
+support storing numbers in parts with 9 digits instead of 7 on Perls with
+either 64bit integer or long double support. This means math operations
+scale better and are thus faster for really big numbers.
+
+=head2 New Core Modules
+
+=over 4
+
+=item *
+
+C<Locale::Maketext::Simple>, needed by CPANPLUS, is a simple wrapper around
+C<Locale::Maketext::Lexicon>. Note that C<Locale::Maketext::Lexicon> isn't
+included in the perl core; the behaviour of C<Locale::Maketext::Simple>
+gracefully degrades when the later isn't present.
+
+=item *
+
+C<Params::Check> implements a generic input parsing/checking mechanism. It
+is used by CPANPLUS.
+
+=item *
+
+C<Term::UI> simplifies the task to ask questions at a terminal prompt.
+
+=item *
+
+C<Object::Accessor> provides an interface to create per-object accessors.
+
+=item *
+
+C<Module::Pluggable> is a simple framework to create modules that accept
+pluggable sub-modules.
+
+=item *
+
+C<Module::Load::Conditional> provides simple ways to query and possibly
+load installed modules.
+
+=item *
+
+C<Time::Piece> provides an object oriented interface to time functions,
+overriding the built-ins localtime() and gmtime().
+
+=item *
+
+C<IPC::Cmd> helps to find and run external commands, possibly
+interactively.
+
+=item *
+
+C<File::Fetch> provide a simple generic file fetching mechanism.
+
+=item *
+
+C<Log::Message> and C<Log::Message::Simple> are used by the log facility
+of C<CPANPLUS>.
+
+=item *
+
+C<Archive::Extract> is a generic archive extraction mechanism
+for F<.tar> (plain, gziped or bzipped) or F<.zip> files.
+
+=item *
+
+C<CPANPLUS> provides an API and a command-line tool to access the CPAN
+mirrors.
+
+=back
+
+=head2 Module changes
+
+=over 4
+
+=item C<assertions>
+
+The C<assertions> pragma, its submodules C<assertions::activate> and
+C<assertions::compat> and the B<-A> command-line switch have been removed.
+The interface was not judged mature enough for inclusion in a stable
+release.
+
+=item C<base>
+
+The C<base> pragma now warns if a class tries to inherit from itself.
+(Curtis "Ovid" Poe)
+
+=item C<strict> and C<warnings>
+
+C<strict> and C<warnings> will now complain loudly if they are loaded via
+incorrect casing (as in C<use Strict;>). (Johan Vromans)
+
+=item C<warnings>
+
+The C<warnings> pragma doesn't load C<Carp> anymore. That means that code
+that used C<Carp> routines without having loaded it at compile time might
+need to be adjusted; typically, the following (faulty) code won't work
+anymore, and will require parentheses to be added after the function name:
+
+ use warnings;
+ require Carp;
+ Carp::confess "argh";
+
+=item C<less>
+
+C<less> now does something useful (or at least it tries to). In fact, it
+has been turned into a lexical pragma. So, in your modules, you can now
+test whether your users have requested to use less CPU, or less memory,
+less magic, or maybe even less fat. See L<less> for more. (Joshua ben
+Jore)
+
+=item C<Attribute::Handlers>
+
+C<Attribute::Handlers> can now report the caller's file and line number.
+(David Feldman)
+
+=item C<B::Lint>
+
+C<B::Lint> is now based on C<Module::Pluggable>, and so can be extended
+with plugins. (Joshua ben Jore)
+
+=item C<B>
+
+It's now possible to access the lexical pragma hints (C<%^H>) by using the
+method B::COP::hints_hash(). It returns a C<B::RHE> object, which in turn
+can be used to get a hash reference via the method B::RHE::HASH(). (Joshua
+ben Jore)
+
+=for p5p XXX document this in B.pm too
+
+=item C<Thread>
+
+As the old 5005thread threading model has been removed, in favor of the
+ithreads scheme, the C<Thread> module is now a compatibility wrapper, to
+be used in old code only. It has been removed from the default list of
+dynamic extensions.
+
+=back
+
+=head1 Utility Changes
+
+=head2 C<cpanp>
+
+C<cpanp>, the CPANPLUS shell, has been added. (C<cpanp-run-perl>, an
+helper for CPANPLUS operation, has been added too, but isn't intended for
+direct use).
+
+=head2 C<cpan2dist>
+
+C<cpan2dist> is a new utility, that comes with CPANPLUS. It's a tool to
+create distributions (or packages) from CPAN modules.
+
+=head2 C<pod2html>
+
+The output of C<pod2html> has been enhanced to be more customizable via
+CSS. Some formatting problems were also corrected. (Jari Aalto)
+
+=head1 Documentation
+
+=head2 New manpage, perlunifaq
+
+A new manual page, L<perlunifaq> (the Perl Unicode FAQ), has been added
+(Juerd Waalboer).
+
+=head1 Installation and Configuration Improvements
+
+=head2 C++ compatibility
+
+Efforts have been made to make perl and the core XS modules compilable
+with various C++ compilers (although the situation is not perfect with
+some of the compilers on some of the platforms tested.)
+
+=head2 Visual C++
+
+Perl now can be compiled with Microsoft Visual C++ 2005.
+
+=head2 Static build on Win32
+
+It's now possible to build a C<perl-static.exe> that doesn't depend
+on C<perl59.dll> on Win32. See the Win32 makefiles for details.
+(Vadim Konovalov)
+
+=head2 win32 builds
+
+All win32 builds (MS-Win, WinCE) have been merged and cleaned up.
+
+=head2 C<d_pseudofork> and C<d_printf_format_null>
+
+A new configuration variable, available as C<$Config{d_pseudofork}> in
+the L<Config> module, has been added, to distinguish real fork() support
+from fake pseudofork used on Windows platforms.
+
+A new configuration variable, C<d_printf_format_null>, has been added,
+to see if printf-like formats are allowed to be NULL.
+
+=head2 Help
+
+C<Configure -h> has been extended with the most used option.
+
+Much less 'Whoa there' messages.
+
+=head2 64bit systems
+
+Better detection of 64bit(only) systems, and setting all the (library)
+paths accordingly.
+
+=head2 Ports
+
+Perl has been reported to work on MidnightBSD.
+
+Support for Cray XT4 Catamount/Qk has been added.
+
+Vendor patches have been merged for RedHat and GenToo.
+
+=head1 Selected Bug Fixes
+
+PerlIO::scalar will now prevent writing to read-only scalars. Moreover,
+seek() is now supported with PerlIO::scalar-based filehandles, the
+underlying string being zero-filled as needed. (Rafael, Jarkko Hietaniemi)
+
+study() never worked for UTF-8 strings, but could lead to false results.
+It's now a no-op on UTF-8 data. (Yves Orton)
+
+The signals SIGILL, SIGBUS and SIGSEGV are now always delivered in an
+"unsafe" manner (contrary to other signals, that are deferred until the
+perl interpreter reaches a reasonably stable state; see
+L<perlipc/"Deferred Signals (Safe Signals)">). (Rafael)
+
+When a module or a file is loaded through an @INC-hook, and when this hook
+has set a filename entry in %INC, __FILE__ is now set for this module
+accordingly to the contents of that %INC entry. (Rafael)
+
+The C<-w> and C<-t> switches can now be used together without messing
+up what categories of warnings are activated or not. (Rafael)
+
+Duping a filehandle which has the C<:utf8> PerlIO layer set will now
+properly carry that layer on the duped filehandle. (Rafael)
+
+Localizing an hash element whose key was given as a variable didn't work
+correctly if the variable was changed while the local() was in effect (as
+in C<local $h{$x}; ++$x>). (Bo Lindbergh)
+
+=head1 New or Changed Diagnostics
+
+=head2 Deprecations
+
+Two deprecation warnings have been added: (Rafael)
+
+ Opening dirhandle %s also as a file
+ Opening filehandle %s also as a directory
+
+=head1 Changed Internals
+
+The anonymous hash and array constructors now take 1 op in the optree
+instead of 3, now that pp_anonhash and pp_anonlist return a reference to
+an hash/array when the op is flagged with OPf_SPECIAL (Nicholas Clark).
+
+=for p5p XXX have we some docs on how to create regexp engine plugins, since that's now possible ? (perlreguts)
+
+=for p5p XXX new BIND SV type, #29544, #29642
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/rt3/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+=head1 SEE ALSO
+
+The F<Changes> file for exhaustive details on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlaix.pod b/Master/tlpkg/tlperl/lib/pods/perlaix.pod
new file mode 100644
index 00000000000..6b86ba62154
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlaix.pod
@@ -0,0 +1,494 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.aix - Perl version 5 on IBM AIX (UNIX) systems
+
+=head1 DESCRIPTION
+
+This document describes various features of IBM's UNIX operating
+system AIX that will affect how Perl version 5 (hereafter just Perl)
+is compiled and/or runs.
+
+=head2 Compiling Perl 5 on AIX
+
+For information on compilers on older versions of AIX, see L<Compiling
+Perl 5 on older AIX versions up to 4.3.3>.
+
+When compiling Perl, you must use an ANSI C compiler. AIX does not ship
+an ANSI compliant C compiler with AIX by default, but binary builds of
+gcc for AIX are widely available. A version of gcc is also included in
+the AIX Toolbox which is shipped with AIX.
+
+=head2 Supported Compilers
+
+Currently all versions of IBM's "xlc", "xlc_r", "cc", "cc_r" or
+"vac" ANSI/C compiler will work for building Perl if that compiler
+works on your system.
+
+If you plan to link Perl to any module that requires thread-support,
+like DBD::Oracle, it is better to use the _r version of the compiler.
+This will not build a threaded Perl, but a thread-enabled Perl. See
+also L<Threaded Perl> later on.
+
+As of writing (2010-09) only the I<IBM XL C for AIX> or I<IBM XL C/C++
+for AIX> compiler is supported by IBM on AIX 5L/6.1/7.1.
+
+The following compiler versions are currently supported by IBM:
+
+ IBM XL C and IBM XL C/C++ V8, V9, V10, V11
+
+The XL C for AIX is integrated in the XL C/C++ for AIX compiler and
+therefore also supported.
+
+If you choose XL C/C++ V9 you need APAR IZ35785 installed
+otherwise the integrated SDBM_File do not compile correctly due
+to an optimization bug. You can circumvent this problem by
+adding -qipa to the optimization flags (-Doptimize='-O -qipa').
+The PTF for APAR IZ35785 which solves this problem is available
+from IBM (April 2009 PTF for XL C/C++ Enterprise Edition for AIX, V9.0).
+
+If you choose XL C/C++ V11 you need the April 2010 PTF (or newer)
+installed otherwise you will not get a working Perl version.
+
+Perl can be compiled with either IBM's ANSI C compiler or with gcc.
+The former is recommended, as not only it can compile Perl with no
+difficulty, but also can take advantage of features listed later
+that require the use of IBM compiler-specific command-line flags.
+
+If you decide to use gcc, make sure your installation is recent and
+complete, and be sure to read the Perl INSTALL file for more gcc-specific
+details. Please report any hoops you had to jump through to the
+development team.
+
+=head2 Incompatibility with AIX Toolbox lib gdbm
+
+If the AIX Toolbox version of lib gdbm < 1.8.3-5 is installed on your
+system then Perl will not work. This library contains the header files
+/opt/freeware/include/gdbm/dbm.h|ndbm.h which conflict with the AIX
+system versions. The lib gdbm will be automatically removed from the
+wanted libraries if the presence of one of these two header files is
+detected. If you want to build Perl with GDBM support then please install
+at least gdbm-devel-1.8.3-5 (or higher).
+
+=head2 Perl 5 was successfully compiled and tested on:
+
+ Perl | AIX Level | Compiler Level | w th | w/o th
+ -------+---------------------+-------------------------+------+-------
+ 5.12.3 |5.1 TL9 32 bit | XL C/C++ V7 | OK | OK
+ 5.12.3 |5.1 TL9 64 bit | XL C/C++ V7 | OK | OK
+ 5.12.3 |5.2 TL10 SP8 32 bit | XL C/C++ V8 | OK | OK
+ 5.12.3 |5.2 TL10 SP8 32 bit | gcc 3.2.2 | OK | OK
+ 5.12.3 |5.2 TL10 SP8 64 bit | XL C/C++ V8 | OK | OK
+ 5.12.3 |5.3 TL8 SP8 32 bit | XL C/C++ V9 + IZ35785 | OK | OK
+ 5.12.3 |5.3 TL8 SP8 32 bit | gcc 4.2.4 | OK | OK
+ 5.12.3 |5.3 TL8 SP8 64 bit | XL C/C++ V9 + IZ35785 | OK | OK
+ 5.12.3 |5.3 TL10 SP3 32 bit | XL C/C++ V11 + Apr 2010 | OK | OK
+ 5.12.3 |5.3 TL10 SP3 64 bit | XL C/C++ V11 + Apr 2010 | OK | OK
+ 5.12.3 |6.1 TL1 SP7 32 bit | XL C/C++ V10 | OK | OK
+ 5.12.3 |6.1 TL1 SP7 64 bit | XL C/C++ V10 | OK | OK
+ 5.13 |7.1 TL0 SP1 32 bit | XL C/C++ V11 + Jul 2010 | OK | OK
+ 5.13 |7.1 TL0 SP1 64 bit | XL C/C++ V11 + Jul 2010 | OK | OK
+
+ w th = with thread support
+ w/o th = without thread support
+ OK = tested
+
+Successfully tested means that all "make test" runs finish with a
+result of 100% OK. All tests were conducted with -Duseshrplib set.
+
+All tests were conducted on the oldest supported AIX technology level
+with the latest support package applied. If the tested AIX version is
+out of support (AIX 4.3.3, 5.1, 5.2) then the last available support
+level was used.
+
+=head2 Building Dynamic Extensions on AIX
+
+Starting from Perl 5.7.2 (and consequently 5.8.x / 5.10.x / 5.12.x)
+and AIX 4.3 or newer Perl uses the AIX native dynamic loading interface
+in the so called runtime linking mode instead of the emulated interface
+that was used in Perl releases 5.6.1 and earlier or, for AIX releases
+4.2 and earlier. This change does break backward compatibility with
+compiled modules from earlier Perl releases. The change was made to make
+Perl more compliant with other applications like Apache/mod_perl which are
+using the AIX native interface. This change also enables the use of
+C++ code with static constructors and destructors in Perl extensions,
+which was not possible using the emulated interface.
+
+It is highly recommended to use the new interface.
+
+=head2 Using Large Files with Perl
+
+Should yield no problems.
+
+=head2 Threaded Perl
+
+Should yield no problems with AIX 5.1 / 5.2 / 5.3 / 6.1 / 7.1.
+
+IBM uses the AIX system Perl (V5.6.0 on AIX 5.1 and V5.8.2 on
+AIX 5.2 / 5.3 and 6.1; V5.8.8 on AIX 5.3 TL11 and AIX 6.1 TL4; V5.10.1
+on AIX 7.1) for some AIX system scripts. If you switch the links in
+/usr/bin from the AIX system Perl (/usr/opt/perl5) to the newly build
+Perl then you get the same features as with the IBM AIX system Perl if
+the threaded options are used.
+
+The threaded Perl build works also on AIX 5.1 but the IBM Perl
+build (Perl v5.6.0) is not threaded on AIX 5.1.
+
+Perl 5.12 an newer is not compatible with the IBM fileset perl.libext.
+
+=head2 64-bit Perl
+
+If your AIX system is installed with 64-bit support, you can expect 64-bit
+configurations to work. If you want to use 64-bit Perl on AIX 6.1
+you need an APAR for a libc.a bug which affects (n)dbm_XXX functions.
+The APAR number for this problem is IZ39077.
+
+If you need more memory (larger data segment) for your Perl programs you
+can set:
+
+ /etc/security/limits
+ default: (or your user)
+ data = -1 (default is 262144 * 512 byte)
+
+With the default setting the size is limited to 128MB.
+The -1 removes this limit. If the "make test" fails please change
+your /etc/security/limits as stated above.
+
+=head2 Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (threaded/32-bit)
+
+With the following options you get a threaded Perl version which
+passes all make tests in threaded 32-bit mode, which is the default
+configuration for the Perl builds that AIX ships with.
+
+ rm config.sh
+ ./Configure \
+ -d \
+ -Dcc=cc_r \
+ -Duseshrplib \
+ -Dusethreads \
+ -Dprefix=/usr/opt/perl5_32
+
+The -Dprefix option will install Perl in a directory parallel to the
+IBM AIX system Perl installation.
+
+=head2 Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (32-bit)
+
+With the following options you get a Perl version which passes
+all make tests in 32-bit mode.
+
+ rm config.sh
+ ./Configure \
+ -d \
+ -Dcc=cc_r \
+ -Duseshrplib \
+ -Dprefix=/usr/opt/perl5_32
+
+The -Dprefix option will install Perl in a directory parallel to the
+IBM AIX system Perl installation.
+
+=head2 Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (threaded/64-bit)
+
+With the following options you get a threaded Perl version which
+passes all make tests in 64-bit mode.
+
+ export OBJECT_MODE=64 / setenv OBJECT_MODE 64 (depending on your shell)
+
+ rm config.sh
+ ./Configure \
+ -d \
+ -Dcc=cc_r \
+ -Duseshrplib \
+ -Dusethreads \
+ -Duse64bitall \
+ -Dprefix=/usr/opt/perl5_64
+
+=head2 Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (64-bit)
+
+With the following options you get a Perl version which passes all
+make tests in 64-bit mode.
+
+ export OBJECT_MODE=64 / setenv OBJECT_MODE 64 (depending on your shell)
+
+ rm config.sh
+ ./Configure \
+ -d \
+ -Dcc=cc_r \
+ -Duseshrplib \
+ -Duse64bitall \
+ -Dprefix=/usr/opt/perl5_64
+
+The -Dprefix option will install Perl in a directory parallel to the
+IBM AIX system Perl installation.
+
+If you choose gcc to compile 64-bit Perl then you need to add the
+following option:
+
+ -Dcc='gcc -maix64'
+
+
+=head2 Compiling Perl 5 on older AIX versions up to 4.3.3
+
+Due to the fact that AIX 4.3.3 reached end-of-service in December 31,
+2003 this information is provided as is. The Perl versions prior to
+Perl 5.8.9 could be compiled on AIX up to 4.3.3 with the following
+settings (your mileage may vary):
+
+When compiling Perl, you must use an ANSI C compiler. AIX does not ship
+an ANSI compliant C-compiler with AIX by default, but binary builds of
+gcc for AIX are widely available.
+
+At the moment of writing, AIX supports two different native C compilers,
+for which you have to pay: B<xlC> and B<vac>. If you decide to use either
+of these two (which is quite a lot easier than using gcc), be sure to
+upgrade to the latest available patch level. Currently:
+
+ xlC.C 3.1.4.10 or 3.6.6.0 or 4.0.2.2 or 5.0.2.9 or 6.0.0.3
+ vac.C 4.4.0.3 or 5.0.2.6 or 6.0.0.1
+
+note that xlC has the OS version in the name as of version 4.0.2.0, so
+you will find xlC.C for AIX-5.0 as package
+
+ xlC.aix50.rte 5.0.2.0 or 6.0.0.3
+
+subversions are not the same "latest" on all OS versions. For example,
+the latest xlC-5 on aix41 is 5.0.2.9, while on aix43, it is 5.0.2.7.
+
+Perl can be compiled with either IBM's ANSI C compiler or with gcc.
+The former is recommended, as not only can it compile Perl with no
+difficulty, but also can take advantage of features listed later that
+require the use of IBM compiler-specific command-line flags.
+
+The IBM's compiler patch levels 5.0.0.0 and 5.0.1.0 have compiler
+optimization bugs that affect compiling perl.c and regcomp.c,
+respectively. If Perl's configuration detects those compiler patch
+levels, optimization is turned off for the said source code files.
+Upgrading to at least 5.0.2.0 is recommended.
+
+If you decide to use gcc, make sure your installation is recent and
+complete, and be sure to read the Perl INSTALL file for more gcc-specific
+details. Please report any hoops you had to jump through to the development
+team.
+
+=head2 OS level
+
+Before installing the patches to the IBM C-compiler you need to know the
+level of patching for the Operating System. IBM's command 'oslevel' will
+show the base, but is not always complete (in this example oslevel shows
+4.3.NULL, whereas the system might run most of 4.3.THREE):
+
+ # oslevel
+ 4.3.0.0
+ # lslpp -l | grep 'bos.rte '
+ bos.rte 4.3.3.75 COMMITTED Base Operating System Runtime
+ bos.rte 4.3.2.0 COMMITTED Base Operating System Runtime
+ #
+
+The same might happen to AIX 5.1 or other OS levels. As a side note, Perl
+cannot be built without bos.adt.syscalls and bos.adt.libm installed
+
+ # lslpp -l | egrep "syscalls|libm"
+ bos.adt.libm 5.1.0.25 COMMITTED Base Application Development
+ bos.adt.syscalls 5.1.0.36 COMMITTED System Calls Application
+ #
+
+=head2 Building Dynamic Extensions on AIX E<lt> 5L
+
+AIX supports dynamically loadable objects as well as shared libraries.
+Shared libraries by convention end with the suffix .a, which is a bit
+misleading, as an archive can contain static as well as dynamic members.
+For Perl dynamically loaded objects we use the .so suffix also used on
+many other platforms.
+
+Note that starting from Perl 5.7.2 (and consequently 5.8.0) and AIX 4.3
+or newer Perl uses the AIX native dynamic loading interface in the so
+called runtime linking mode instead of the emulated interface that was
+used in Perl releases 5.6.1 and earlier or, for AIX releases 4.2 and
+earlier. This change does break backward compatibility with compiled
+modules from earlier Perl releases. The change was made to make Perl
+more compliant with other applications like Apache/mod_perl which are
+using the AIX native interface. This change also enables the use of C++
+code with static constructors and destructors in Perl extensions, which
+was not possible using the emulated interface.
+
+=head2 The IBM ANSI C Compiler
+
+All defaults for Configure can be used.
+
+If you've chosen to use vac 4, be sure to run 4.4.0.3. Older versions
+will turn up nasty later on. For vac 5 be sure to run at least 5.0.1.0,
+but vac 5.0.2.6 or up is highly recommended. Note that since IBM has
+removed vac 5.0.2.1 through 5.0.2.5 from the software depot, these
+versions should be considered obsolete.
+
+Here's a brief lead of how to upgrade the compiler to the latest
+level. Of course this is subject to changes. You can only upgrade
+versions from ftp-available updates if the first three digit groups
+are the same (in where you can skip intermediate unlike the patches
+in the developer snapshots of Perl), or to one version up where the
+"base" is available. In other words, the AIX compiler patches are
+cumulative.
+
+ vac.C.4.4.0.1 => vac.C.4.4.0.3 is OK (vac.C.4.4.0.2 not needed)
+ xlC.C.3.1.3.3 => xlC.C.3.1.4.10 is NOT OK (xlC.C.3.1.4.0 is not available)
+
+ # ftp ftp.software.ibm.com
+ Connected to service.boulder.ibm.com.
+ : welcome message ...
+ Name (ftp.software.ibm.com:merijn): anonymous
+ 331 Guest login ok, send your complete e-mail address as password.
+ Password:
+ ... accepted login stuff
+ ftp> cd /aix/fixes/v4/
+ ftp> dir other other.ll
+ output to local-file: other.ll? y
+ 200 PORT command successful.
+ 150 Opening ASCII mode data connection for /bin/ls.
+ 226 Transfer complete.
+ ftp> dir xlc xlc.ll
+ output to local-file: xlc.ll? y
+ 200 PORT command successful.
+ 150 Opening ASCII mode data connection for /bin/ls.
+ 226 Transfer complete.
+ ftp> bye
+ ... goodbye messages
+ # ls -l *.ll
+ -rw-rw-rw- 1 merijn system 1169432 Nov 2 17:29 other.ll
+ -rw-rw-rw- 1 merijn system 29170 Nov 2 17:29 xlc.ll
+
+On AIX 4.2 using xlC, we continue:
+
+ # lslpp -l | fgrep 'xlC.C '
+ xlC.C 3.1.4.9 COMMITTED C for AIX Compiler
+ xlC.C 3.1.4.0 COMMITTED C for AIX Compiler
+ # grep 'xlC.C.3.1.4.*.bff' xlc.ll
+ -rw-r--r-- 1 45776101 1 6286336 Jul 22 1996 xlC.C.3.1.4.1.bff
+ -rw-rw-r-- 1 45776101 1 6173696 Aug 24 1998 xlC.C.3.1.4.10.bff
+ -rw-r--r-- 1 45776101 1 6319104 Aug 14 1996 xlC.C.3.1.4.2.bff
+ -rw-r--r-- 1 45776101 1 6316032 Oct 21 1996 xlC.C.3.1.4.3.bff
+ -rw-r--r-- 1 45776101 1 6315008 Dec 20 1996 xlC.C.3.1.4.4.bff
+ -rw-rw-r-- 1 45776101 1 6178816 Mar 28 1997 xlC.C.3.1.4.5.bff
+ -rw-rw-r-- 1 45776101 1 6188032 May 22 1997 xlC.C.3.1.4.6.bff
+ -rw-rw-r-- 1 45776101 1 6191104 Sep 5 1997 xlC.C.3.1.4.7.bff
+ -rw-rw-r-- 1 45776101 1 6185984 Jan 13 1998 xlC.C.3.1.4.8.bff
+ -rw-rw-r-- 1 45776101 1 6169600 May 27 1998 xlC.C.3.1.4.9.bff
+ # wget ftp://ftp.software.ibm.com/aix/fixes/v4/xlc/xlC.C.3.1.4.10.bff
+ #
+
+On AIX 4.3 using vac, we continue:
+
+ # lslpp -l | grep 'vac.C '
+ vac.C 5.0.2.2 COMMITTED C for AIX Compiler
+ vac.C 5.0.2.0 COMMITTED C for AIX Compiler
+ # grep 'vac.C.5.0.2.*.bff' other.ll
+ -rw-rw-r-- 1 45776101 1 13592576 Apr 16 2001 vac.C.5.0.2.0.bff
+ -rw-rw-r-- 1 45776101 1 14133248 Apr 9 2002 vac.C.5.0.2.3.bff
+ -rw-rw-r-- 1 45776101 1 14173184 May 20 2002 vac.C.5.0.2.4.bff
+ -rw-rw-r-- 1 45776101 1 14192640 Nov 22 2002 vac.C.5.0.2.6.bff
+ # wget ftp://ftp.software.ibm.com/aix/fixes/v4/other/vac.C.5.0.2.6.bff
+ #
+
+Likewise on all other OS levels. Then execute the following command, and
+fill in its choices
+
+ # smit install_update
+ -> Install and Update from LATEST Available Software
+ * INPUT device / directory for software [ vac.C.5.0.2.6.bff ]
+ [ OK ]
+ [ OK ]
+
+Follow the messages ... and you're done.
+
+If you like a more web-like approach, a good start point can be
+http://www14.software.ibm.com/webapp/download/downloadaz.jsp and click
+"C for AIX", and follow the instructions.
+
+=head2 The usenm option
+
+If linking miniperl
+
+ cc -o miniperl ... miniperlmain.o opmini.o perl.o ... -lm -lc ...
+
+causes error like this
+
+ ld: 0711-317 ERROR: Undefined symbol: .aintl
+ ld: 0711-317 ERROR: Undefined symbol: .copysignl
+ ld: 0711-317 ERROR: Undefined symbol: .syscall
+ ld: 0711-317 ERROR: Undefined symbol: .eaccess
+ ld: 0711-317 ERROR: Undefined symbol: .setresuid
+ ld: 0711-317 ERROR: Undefined symbol: .setresgid
+ ld: 0711-317 ERROR: Undefined symbol: .setproctitle
+ ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information.
+
+you could retry with
+
+ make realclean
+ rm config.sh
+ ./Configure -Dusenm ...
+
+which makes Configure to use the C<nm> tool when scanning for library
+symbols, which usually is not done in AIX.
+
+Related to this, you probably should not use the C<-r> option of
+Configure in AIX, because that affects of how the C<nm> tool is used.
+
+=head2 Using GNU's gcc for building Perl
+
+Using gcc-3.x (tested with 3.0.4, 3.1, and 3.2) now works out of the box,
+as do recent gcc-2.9 builds available directly from IBM as part of their
+Linux compatibility packages, available here:
+
+ http://www.ibm.com/servers/aix/products/aixos/linux/
+
+=head2 Using Large Files with Perl E<lt> 5L
+
+Should yield no problems.
+
+=head2 Threaded Perl E<lt> 5L
+
+Threads seem to work OK, though at the moment not all tests pass when
+threads are used in combination with 64-bit configurations.
+
+You may get a warning when doing a threaded build:
+
+ "pp_sys.c", line 4640.39: 1506-280 (W) Function argument assignment
+ between types "unsigned char*" and "const void*" is not allowed.
+
+The exact line number may vary, but if the warning (W) comes from a line
+line this
+
+ hent = PerlSock_gethostbyaddr(addr, (Netdb_hlen_t) addrlen, addrtype);
+
+in the "pp_ghostent" function, you may ignore it safely. The warning
+is caused by the reentrant variant of gethostbyaddr() having a slightly
+different prototype than its non-reentrant variant, but the difference
+is not really significant here.
+
+=head2 64-bit Perl E<lt> 5L
+
+If your AIX is installed with 64-bit support, you can expect 64-bit
+configurations to work. In combination with threads some tests might
+still fail.
+
+=head2 AIX 4.2 and extensions using C++ with statics
+
+In AIX 4.2 Perl extensions that use C++ functions that use statics
+may have problems in that the statics are not getting initialized.
+In newer AIX releases this has been solved by linking Perl with
+the libC_r library, but unfortunately in AIX 4.2 the said library
+has an obscure bug where the various functions related to time
+(such as time() and gettimeofday()) return broken values, and
+therefore in AIX 4.2 Perl is not linked against the libC_r.
+
+=head1 AUTHORS
+
+H.Merijn Brand <h.m.brand@xs4all.nl>
+Rainer Tammer <tammer@tammer.net>
+
+=head1 DATE
+
+Version 5.12.1 / 2010-05-14
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlamiga.pod b/Master/tlpkg/tlperl/lib/pods/perlamiga.pod
new file mode 100644
index 00000000000..418a5fe635f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlamiga.pod
@@ -0,0 +1,278 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perlamiga - Perl under Amiga OS
+
+=head1 NOTE
+
+B<Perl 5.8.0 cannot be built in AmigaOS. You can use either the
+maintenance release Perl 5.6.1 or the development release Perl 5.7.2
+in AmigaOS. See L</"PERL 5.8.0 BROKEN IN AMIGAOS"> if you want to help
+fixing this problem.>
+
+=head1 SYNOPSIS
+
+One can read this document in the following formats:
+
+ man perlamiga
+ multiview perlamiga.guide
+
+to list some (not all may be available simultaneously), or it may
+be read I<as is>: either as F<README.amiga>, or F<pod/perlamiga.pod>.
+
+A recent version of perl for the Amiga can be found at the Geek Gadgets
+section of the Aminet:
+
+ http://www.aminet.net/~aminet/dev/gg
+
+=cut
+
+Contents
+
+ perlamiga - Perl under Amiga OS
+
+ NAME
+ SYNOPSIS
+ DESCRIPTION
+ - Prerequisites
+ - Starting Perl programs under AmigaOS
+ - Shortcomings of Perl under AmigaOS
+ INSTALLATION
+ Accessing documentation
+ - Manpages
+ - HTML
+ - GNU info files
+ - LaTeX docs
+ BUILD
+ - Build Prerequisites
+ - Getting the perl source
+ - Application of the patches
+ - Making
+ - Testing
+ - Installing the built perl
+ AUTHOR
+ SEE ALSO
+
+=head1 DESCRIPTION
+
+=head2 Prerequisites for Compiling Perl on AmigaOS
+
+=over 6
+
+=item B<Unix emulation for AmigaOS: ixemul.library>
+
+You need the Unix emulation for AmigaOS, whose most important part is
+B<ixemul.library>. For a minimum setup, get the latest versions
+of the following packages from the Aminet archives
+( http://www.aminet.net/~aminet/ ):
+
+ ixemul-bin
+ ixemul-env-bin
+ pdksh-bin
+
+Note also that this is a minimum setup; you might want to add other
+packages of B<ADE> (the I<Amiga Developers Environment>).
+
+=item B<Version of Amiga OS>
+
+You need at the very least AmigaOS version 2.0. Recommended is version 3.1.
+
+=back
+
+=head2 Starting Perl programs under AmigaOS
+
+Start your Perl program F<foo> with arguments C<arg1 arg2 arg3> the
+same way as on any other platform, by
+
+ perl foo arg1 arg2 arg3
+
+If you want to specify perl options C<-my_opts> to the perl itself (as
+opposed to your program), use
+
+ perl -my_opts foo arg1 arg2 arg3
+
+Alternately, you can try to get a replacement for the system's B<Execute>
+command that honors the #!/usr/bin/perl syntax in scripts and set the s-Bit
+of your scripts. Then you can invoke your scripts like under UNIX with
+
+ foo arg1 arg2 arg3
+
+(Note that having *nixish full path to perl F</usr/bin/perl> is not
+necessary, F<perl> would be enough, but having full path would make it
+easier to use your script under *nix.)
+
+=head2 Shortcomings of Perl under AmigaOS
+
+Perl under AmigaOS lacks some features of perl under UNIX because of
+deficiencies in the UNIX-emulation, most notably:
+
+=over 6
+
+=item *
+
+fork()
+
+=item *
+
+some features of the UNIX filesystem regarding link count and file dates
+
+=item *
+
+inplace operation (the -i switch) without backup file
+
+=item *
+
+umask() works, but the correct permissions are only set when the file is
+finally close()d
+
+=back
+
+=head1 INSTALLATION
+
+Change to the installation directory (most probably ADE:), and
+extract the binary distribution:
+
+lha -mraxe x perl-$VERSION-bin.lha
+
+or
+
+tar xvzpf perl-$VERSION-bin.tgz
+
+(Of course you need lha or tar and gunzip for this.)
+
+For installation of the Unix emulation, read the appropriate docs.
+
+=head1 Accessing documentation
+
+=head2 Manpages for Perl on AmigaOS
+
+If you have C<man> installed on your system, and you installed perl
+manpages, use something like this:
+
+ man perlfunc
+ man less
+ man ExtUtils.MakeMaker
+
+to access documentation for different components of Perl. Start with
+
+ man perl
+
+Note: You have to modify your man.conf file to search for manpages
+in the /ade/lib/perl5/man/man3 directory, or the man pages for the
+perl library will not be found.
+
+Note that dot (F<.>) is used as a package separator for documentation
+for packages, and as usual, sometimes you need to give the section - C<3>
+above - to avoid shadowing by the I<less(1) manpage>.
+
+
+=head2 Perl HTML Documentation on AmigaOS
+
+If you have some WWW browser available, you can build B<HTML> docs.
+Cd to directory with F<.pod> files, and do like this
+
+ cd /ade/lib/perl5/pod
+ pod2html
+
+After this you can direct your browser the file F<perl.html> in this
+directory, and go ahead with reading docs.
+
+Alternatively you may be able to get these docs prebuilt from C<CPAN>.
+
+=head2 Perl GNU Info Files on AmigaOS
+
+Users of C<Emacs> would appreciate it very much, especially with
+C<CPerl> mode loaded. You need to get latest C<pod2info> from C<CPAN>,
+or, alternately, prebuilt info pages.
+
+=head2 Perl LaTeX Documentation on AmigaOS
+
+Can be constructed using C<pod2latex>.
+
+=head1 BUILDING PERL ON AMIGAOS
+
+Here we discuss how to build Perl under AmigaOS.
+
+=head2 Build Prerequisites for Perl on AmigaOS
+
+You need to have the latest B<ixemul> (Unix emulation for Amiga)
+from Aminet.
+
+=head2 Getting the Perl Source for AmigaOS
+
+You can either get the latest perl-for-amiga source from Ninemoons
+and extract it with:
+
+ tar xvzpf perl-$VERSION-src.tgz
+
+or get the official source from CPAN:
+
+ http://www.cpan.org/src/5.0
+
+Extract it like this
+
+ tar xvzpf perl-$VERSION.tar.gz
+
+You will see a message about errors while extracting F<Configure>. This
+is normal and expected. (There is a conflict with a similarly-named file
+F<configure>, but it causes no harm.)
+
+=head2 Making Perl on AmigaOS
+
+Remember to use a hefty wad of stack (I use 2000000)
+
+ sh configure.gnu --prefix=/gg
+
+Now type
+
+ make depend
+
+Now!
+
+ make
+
+=head2 Testing Perl on AmigaOS
+
+Now run
+
+ make test
+
+Some tests will be skipped because they need the fork() function:
+
+F<io/pipe.t>, F<op/fork.t>, F<lib/filehand.t>, F<lib/open2.t>, F<lib/open3.t>,
+F<lib/io_pipe.t>, F<lib/io_sock.t>
+
+=head2 Installing the built Perl on AmigaOS
+
+Run
+
+ make install
+
+=head1 PERL 5.8.0 BROKEN IN AMIGAOS
+
+As told above, Perl 5.6.1 was still good in AmigaOS, as was 5.7.2.
+After Perl 5.7.2 (change #11423, see the Changes file, and the file
+pod/perlhack.pod for how to get the individual changes) Perl dropped
+its internal support for vfork(), and that was very probably the step
+that broke AmigaOS (since the ixemul library has only vfork).
+The build finally fails when the ext/DynaLoader is being built, and
+PERL ends up as "0" in the produced Makefile, trying to run "0" does
+not quite work. Also, executing miniperl in backticks seems to
+generate nothing: very probably related to the (v)fork problems.
+B<Fixing the breakage requires someone quite familiar with the ixemul
+library, and how one is supposed to run external commands in AmigaOS
+without fork().>
+
+=head1 AUTHORS
+
+Norbert Pueschel, pueschel@imsdd.meb.uni-bonn.de
+Jan-Erik Karlsson, trg@privat.utfors.se
+
+=head1 SEE ALSO
+
+perl(1).
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlapi.pod b/Master/tlpkg/tlperl/lib/pods/perlapi.pod
new file mode 100644
index 00000000000..3a8792b899d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlapi.pod
@@ -0,0 +1,9328 @@
+-*- buffer-read-only: t -*-
+
+!!!!!!! DO NOT EDIT THIS FILE !!!!!!!
+This file is built by ..\autodoc.pl extracting documentation from the C source
+files.
+
+=head1 NAME
+
+perlapi - autogenerated documentation for the perl public API
+
+=head1 DESCRIPTION
+X<Perl API> X<API> X<api>
+
+This file contains the documentation of the perl public API generated by
+embed.pl, specifically a listing of functions, macros, flags, and variables
+that may be used by extension writers. The interfaces of any functions that
+are not listed here are subject to change without notice. For this reason,
+blindly using functions listed in proto.h is to be avoided when writing
+extensions.
+
+Note that all Perl API global variables must be referenced with the C<PL_>
+prefix. Some macros are provided for compatibility with the older,
+unadorned names, but this support may be disabled in a future release.
+
+Perl was originally written to handle US-ASCII only (that is characters
+whose ordinal numbers are in the range 0 - 127).
+And documentation and comments may still use the term ASCII, when
+sometimes in fact the entire range from 0 - 255 is meant.
+
+Note that Perl can be compiled and run under EBCDIC (See L<perlebcdic>)
+or ASCII. Most of the documentation (and even comments in the code)
+ignore the EBCDIC possibility.
+For almost all purposes the differences are transparent.
+As an example, under EBCDIC,
+instead of UTF-8, UTF-EBCDIC is used to encode Unicode strings, and so
+whenever this documentation refers to C<utf8>
+(and variants of that name, including in function names),
+it also (essentially transparently) means C<UTF-EBCDIC>.
+But the ordinals of characters differ between ASCII, EBCDIC, and
+the UTF- encodings, and a string encoded in UTF-EBCDIC may occupy more bytes
+than in UTF-8.
+
+Also, on some EBCDIC machines, functions that are documented as operating on
+US-ASCII (or Basic Latin in Unicode terminology) may in fact operate on all
+256 characters in the EBCDIC range, not just the subset corresponding to
+US-ASCII.
+
+The listing below is alphabetical, case insensitive.
+
+
+=head1 "Gimme" Values
+
+=over 8
+
+=item GIMME
+X<GIMME>
+
+A backward-compatible version of C<GIMME_V> which can only return
+C<G_SCALAR> or C<G_ARRAY>; in a void context, it returns C<G_SCALAR>.
+Deprecated. Use C<GIMME_V> instead.
+
+ U32 GIMME
+
+=for hackers
+Found in file op.h
+
+=item GIMME_V
+X<GIMME_V>
+
+The XSUB-writer's equivalent to Perl's C<wantarray>. Returns C<G_VOID>,
+C<G_SCALAR> or C<G_ARRAY> for void, scalar or list context,
+respectively.
+
+ U32 GIMME_V
+
+=for hackers
+Found in file op.h
+
+=item G_ARRAY
+X<G_ARRAY>
+
+Used to indicate list context. See C<GIMME_V>, C<GIMME> and
+L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+=item G_DISCARD
+X<G_DISCARD>
+
+Indicates that arguments returned from a callback should be discarded. See
+L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+=item G_EVAL
+X<G_EVAL>
+
+Used to force a Perl C<eval> wrapper around a callback. See
+L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+=item G_NOARGS
+X<G_NOARGS>
+
+Indicates that no arguments are being sent to a callback. See
+L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+=item G_SCALAR
+X<G_SCALAR>
+
+Used to indicate scalar context. See C<GIMME_V>, C<GIMME>, and
+L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+=item G_VOID
+X<G_VOID>
+
+Used to indicate void context. See C<GIMME_V> and L<perlcall>.
+
+=for hackers
+Found in file cop.h
+
+
+=back
+
+=head1 Array Manipulation Functions
+
+=over 8
+
+=item AvFILL
+X<AvFILL>
+
+Same as C<av_len()>. Deprecated, use C<av_len()> instead.
+
+ int AvFILL(AV* av)
+
+=for hackers
+Found in file av.h
+
+=item av_clear
+X<av_clear>
+
+Clears an array, making it empty. Does not free the memory used by the
+array itself.
+
+ void av_clear(AV *av)
+
+=for hackers
+Found in file av.c
+
+=item av_create_and_push
+X<av_create_and_push>
+
+Push an SV onto the end of the array, creating the array if necessary.
+A small internal helper function to remove a commonly duplicated idiom.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void av_create_and_push(AV **const avp, SV *const val)
+
+=for hackers
+Found in file av.c
+
+=item av_create_and_unshift_one
+X<av_create_and_unshift_one>
+
+Unshifts an SV onto the beginning of the array, creating the array if
+necessary.
+A small internal helper function to remove a commonly duplicated idiom.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ SV** av_create_and_unshift_one(AV **const avp, SV *const val)
+
+=for hackers
+Found in file av.c
+
+=item av_delete
+X<av_delete>
+
+Deletes the element indexed by C<key> from the array. Returns the
+deleted element. If C<flags> equals C<G_DISCARD>, the element is freed
+and null is returned.
+
+ SV* av_delete(AV *av, I32 key, I32 flags)
+
+=for hackers
+Found in file av.c
+
+=item av_exists
+X<av_exists>
+
+Returns true if the element indexed by C<key> has been initialized.
+
+This relies on the fact that uninitialized array elements are set to
+C<&PL_sv_undef>.
+
+ bool av_exists(AV *av, I32 key)
+
+=for hackers
+Found in file av.c
+
+=item av_extend
+X<av_extend>
+
+Pre-extend an array. The C<key> is the index to which the array should be
+extended.
+
+ void av_extend(AV *av, I32 key)
+
+=for hackers
+Found in file av.c
+
+=item av_fetch
+X<av_fetch>
+
+Returns the SV at the specified index in the array. The C<key> is the
+index. If C<lval> is set then the fetch will be part of a store. Check
+that the return value is non-null before dereferencing it to a C<SV*>.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for
+more information on how to use this function on tied arrays.
+
+ SV** av_fetch(AV *av, I32 key, I32 lval)
+
+=for hackers
+Found in file av.c
+
+=item av_fill
+X<av_fill>
+
+Set the highest index in the array to the given number, equivalent to
+Perl's C<$#array = $fill;>.
+
+The number of elements in the an array will be C<fill + 1> after
+av_fill() returns. If the array was previously shorter then the
+additional elements appended are set to C<PL_sv_undef>. If the array
+was longer, then the excess elements are freed. C<av_fill(av, -1)> is
+the same as C<av_clear(av)>.
+
+ void av_fill(AV *av, I32 fill)
+
+=for hackers
+Found in file av.c
+
+=item av_len
+X<av_len>
+
+Returns the highest index in the array. The number of elements in the
+array is C<av_len(av) + 1>. Returns -1 if the array is empty.
+
+ I32 av_len(AV *av)
+
+=for hackers
+Found in file av.c
+
+=item av_make
+X<av_make>
+
+Creates a new AV and populates it with a list of SVs. The SVs are copied
+into the array, so they may be freed after the call to av_make. The new AV
+will have a reference count of 1.
+
+ AV* av_make(I32 size, SV **strp)
+
+=for hackers
+Found in file av.c
+
+=item av_pop
+X<av_pop>
+
+Pops an SV off the end of the array. Returns C<&PL_sv_undef> if the array
+is empty.
+
+ SV* av_pop(AV *av)
+
+=for hackers
+Found in file av.c
+
+=item av_push
+X<av_push>
+
+Pushes an SV onto the end of the array. The array will grow automatically
+to accommodate the addition. Like C<av_store>, this takes ownership of one
+reference count.
+
+ void av_push(AV *av, SV *val)
+
+=for hackers
+Found in file av.c
+
+=item av_shift
+X<av_shift>
+
+Shifts an SV off the beginning of the array. Returns C<&PL_sv_undef> if the
+array is empty.
+
+ SV* av_shift(AV *av)
+
+=for hackers
+Found in file av.c
+
+=item av_store
+X<av_store>
+
+Stores an SV in an array. The array index is specified as C<key>. The
+return value will be NULL if the operation failed or if the value did not
+need to be actually stored within the array (as in the case of tied
+arrays). Otherwise it can be dereferenced to get the original C<SV*>. Note
+that the caller is responsible for suitably incrementing the reference
+count of C<val> before the call, and decrementing it if the function
+returned NULL.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for
+more information on how to use this function on tied arrays.
+
+ SV** av_store(AV *av, I32 key, SV *val)
+
+=for hackers
+Found in file av.c
+
+=item av_undef
+X<av_undef>
+
+Undefines the array. Frees the memory used by the array itself.
+
+ void av_undef(AV *av)
+
+=for hackers
+Found in file av.c
+
+=item av_unshift
+X<av_unshift>
+
+Unshift the given number of C<undef> values onto the beginning of the
+array. The array will grow automatically to accommodate the addition. You
+must then use C<av_store> to assign values to these new elements.
+
+ void av_unshift(AV *av, I32 num)
+
+=for hackers
+Found in file av.c
+
+=item get_av
+X<get_av>
+
+Returns the AV of the specified Perl array. C<flags> are passed to
+C<gv_fetchpv>. If C<GV_ADD> is set and the
+Perl variable does not exist then it will be created. If C<flags> is zero
+and the variable does not exist then NULL is returned.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ AV* get_av(const char *name, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item newAV
+X<newAV>
+
+Creates a new AV. The reference count is set to 1.
+
+ AV* newAV()
+
+=for hackers
+Found in file av.h
+
+=item sortsv
+X<sortsv>
+
+Sort an array. Here is an example:
+
+ sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale);
+
+Currently this always uses mergesort. See sortsv_flags for a more
+flexible routine.
+
+ void sortsv(SV** array, size_t num_elts, SVCOMPARE_t cmp)
+
+=for hackers
+Found in file pp_sort.c
+
+=item sortsv_flags
+X<sortsv_flags>
+
+Sort an array, with various options.
+
+ void sortsv_flags(SV** array, size_t num_elts, SVCOMPARE_t cmp, U32 flags)
+
+=for hackers
+Found in file pp_sort.c
+
+
+=back
+
+=head1 Callback Functions
+
+=over 8
+
+=item call_argv
+X<call_argv>
+
+Performs a callback to the specified Perl sub. See L<perlcall>.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ I32 call_argv(const char* sub_name, I32 flags, char** argv)
+
+=for hackers
+Found in file perl.c
+
+=item call_method
+X<call_method>
+
+Performs a callback to the specified Perl method. The blessed object must
+be on the stack. See L<perlcall>.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ I32 call_method(const char* methname, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item call_pv
+X<call_pv>
+
+Performs a callback to the specified Perl sub. See L<perlcall>.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ I32 call_pv(const char* sub_name, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item call_sv
+X<call_sv>
+
+Performs a callback to the Perl sub whose name is in the SV. See
+L<perlcall>.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ I32 call_sv(SV* sv, VOL I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item ENTER
+X<ENTER>
+
+Opening bracket on a callback. See C<LEAVE> and L<perlcall>.
+
+ ENTER;
+
+=for hackers
+Found in file scope.h
+
+=item eval_pv
+X<eval_pv>
+
+Tells Perl to C<eval> the given string and return an SV* result.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ SV* eval_pv(const char* p, I32 croak_on_error)
+
+=for hackers
+Found in file perl.c
+
+=item eval_sv
+X<eval_sv>
+
+Tells Perl to C<eval> the string in the SV.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ I32 eval_sv(SV* sv, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item FREETMPS
+X<FREETMPS>
+
+Closing bracket for temporaries on a callback. See C<SAVETMPS> and
+L<perlcall>.
+
+ FREETMPS;
+
+=for hackers
+Found in file scope.h
+
+=item LEAVE
+X<LEAVE>
+
+Closing bracket on a callback. See C<ENTER> and L<perlcall>.
+
+ LEAVE;
+
+=for hackers
+Found in file scope.h
+
+=item SAVETMPS
+X<SAVETMPS>
+
+Opening bracket for temporaries on a callback. See C<FREETMPS> and
+L<perlcall>.
+
+ SAVETMPS;
+
+=for hackers
+Found in file scope.h
+
+
+=back
+
+=head1 Character classes
+
+=over 8
+
+=item isALNUM
+X<isALNUM>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+alphanumeric character (including underscore) or digit.
+
+ bool isALNUM(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item isALPHA
+X<isALPHA>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+alphabetic character.
+
+ bool isALPHA(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item isDIGIT
+X<isDIGIT>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+digit.
+
+ bool isDIGIT(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item isLOWER
+X<isLOWER>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+lowercase character.
+
+ bool isLOWER(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item isSPACE
+X<isSPACE>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+whitespace.
+
+ bool isSPACE(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item isUPPER
+X<isUPPER>
+
+Returns a boolean indicating whether the C C<char> is a US-ASCII (Basic Latin)
+uppercase character.
+
+ bool isUPPER(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item toLOWER
+X<toLOWER>
+
+Converts the specified character to lowercase. Characters outside the
+US-ASCII (Basic Latin) range are viewed as not having any case.
+
+ char toLOWER(char ch)
+
+=for hackers
+Found in file handy.h
+
+=item toUPPER
+X<toUPPER>
+
+Converts the specified character to uppercase. Characters outside the
+US-ASCII (Basic Latin) range are viewed as not having any case.
+
+ char toUPPER(char ch)
+
+=for hackers
+Found in file handy.h
+
+
+=back
+
+=head1 Cloning an interpreter
+
+=over 8
+
+=item perl_clone
+X<perl_clone>
+
+Create and return a new interpreter by cloning the current one.
+
+perl_clone takes these flags as parameters:
+
+CLONEf_COPY_STACKS - is used to, well, copy the stacks also,
+without it we only clone the data and zero the stacks,
+with it we copy the stacks and the new perl interpreter is
+ready to run at the exact same point as the previous one.
+The pseudo-fork code uses COPY_STACKS while the
+threads->create doesn't.
+
+CLONEf_KEEP_PTR_TABLE
+perl_clone keeps a ptr_table with the pointer of the old
+variable as a key and the new variable as a value,
+this allows it to check if something has been cloned and not
+clone it again but rather just use the value and increase the
+refcount. If KEEP_PTR_TABLE is not set then perl_clone will kill
+the ptr_table using the function
+C<ptr_table_free(PL_ptr_table); PL_ptr_table = NULL;>,
+reason to keep it around is if you want to dup some of your own
+variable who are outside the graph perl scans, example of this
+code is in threads.xs create
+
+CLONEf_CLONE_HOST
+This is a win32 thing, it is ignored on unix, it tells perls
+win32host code (which is c++) to clone itself, this is needed on
+win32 if you want to run two threads at the same time,
+if you just want to do some stuff in a separate perl interpreter
+and then throw it away and return to the original one,
+you don't need to do anything.
+
+ PerlInterpreter* perl_clone(PerlInterpreter *proto_perl, UV flags)
+
+=for hackers
+Found in file sv.c
+
+
+=back
+
+=head1 CV Manipulation Functions
+
+=over 8
+
+=item CvSTASH
+X<CvSTASH>
+
+Returns the stash of the CV.
+
+ HV* CvSTASH(CV* cv)
+
+=for hackers
+Found in file cv.h
+
+=item get_cv
+X<get_cv>
+
+Uses C<strlen> to get the length of C<name>, then calls C<get_cvn_flags>.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ CV* get_cv(const char* name, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item get_cvn_flags
+X<get_cvn_flags>
+
+Returns the CV of the specified Perl subroutine. C<flags> are passed to
+C<gv_fetchpvn_flags>. If C<GV_ADD> is set and the Perl subroutine does not
+exist then it will be declared (which has the same effect as saying
+C<sub name;>). If C<GV_ADD> is not set and the subroutine does not exist
+then NULL is returned.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ CV* get_cvn_flags(const char* name, STRLEN len, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+
+=back
+
+=head1 Embedding Functions
+
+=over 8
+
+=item cv_undef
+X<cv_undef>
+
+Clear out all the active components of a CV. This can happen either
+by an explicit C<undef &foo>, or by the reference count going to zero.
+In the former case, we keep the CvOUTSIDE pointer, so that any anonymous
+children can still follow the full lexical scope chain.
+
+ void cv_undef(CV* cv)
+
+=for hackers
+Found in file op.c
+
+=item load_module
+X<load_module>
+
+Loads the module whose name is pointed to by the string part of name.
+Note that the actual module name, not its filename, should be given.
+Eg, "Foo::Bar" instead of "Foo/Bar.pm". flags can be any of
+PERL_LOADMOD_DENY, PERL_LOADMOD_NOIMPORT, or PERL_LOADMOD_IMPORT_OPS
+(or 0 for no flags). ver, if specified, provides version semantics
+similar to C<use Foo::Bar VERSION>. The optional trailing SV*
+arguments can be used to specify arguments to the module's import()
+method, similar to C<use Foo::Bar VERSION LIST>. They must be
+terminated with a final NULL pointer. Note that this list can only
+be omitted when the PERL_LOADMOD_NOIMPORT flag has been used.
+Otherwise at least a single NULL pointer to designate the default
+import list is required.
+
+ void load_module(U32 flags, SV* name, SV* ver, ...)
+
+=for hackers
+Found in file op.c
+
+=item nothreadhook
+X<nothreadhook>
+
+Stub that provides thread hook for perl_destruct when there are
+no threads.
+
+ int nothreadhook()
+
+=for hackers
+Found in file perl.c
+
+=item perl_alloc
+X<perl_alloc>
+
+Allocates a new Perl interpreter. See L<perlembed>.
+
+ PerlInterpreter* perl_alloc()
+
+=for hackers
+Found in file perl.c
+
+=item perl_construct
+X<perl_construct>
+
+Initializes a new Perl interpreter. See L<perlembed>.
+
+ void perl_construct(PerlInterpreter *my_perl)
+
+=for hackers
+Found in file perl.c
+
+=item perl_destruct
+X<perl_destruct>
+
+Shuts down a Perl interpreter. See L<perlembed>.
+
+ int perl_destruct(PerlInterpreter *my_perl)
+
+=for hackers
+Found in file perl.c
+
+=item perl_free
+X<perl_free>
+
+Releases a Perl interpreter. See L<perlembed>.
+
+ void perl_free(PerlInterpreter *my_perl)
+
+=for hackers
+Found in file perl.c
+
+=item perl_parse
+X<perl_parse>
+
+Tells a Perl interpreter to parse a Perl script. See L<perlembed>.
+
+ int perl_parse(PerlInterpreter *my_perl, XSINIT_t xsinit, int argc, char** argv, char** env)
+
+=for hackers
+Found in file perl.c
+
+=item perl_run
+X<perl_run>
+
+Tells a Perl interpreter to run. See L<perlembed>.
+
+ int perl_run(PerlInterpreter *my_perl)
+
+=for hackers
+Found in file perl.c
+
+=item require_pv
+X<require_pv>
+
+Tells Perl to C<require> the file named by the string argument. It is
+analogous to the Perl code C<eval "require '$file'">. It's even
+implemented that way; consider using load_module instead.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ void require_pv(const char* pv)
+
+=for hackers
+Found in file perl.c
+
+
+=back
+
+=head1 Functions in file dump.c
+
+
+=over 8
+
+=item pv_display
+X<pv_display>
+
+Similar to
+
+ pv_escape(dsv,pv,cur,pvlim,PERL_PV_ESCAPE_QUOTE);
+
+except that an additional "\0" will be appended to the string when
+len > cur and pv[cur] is "\0".
+
+Note that the final string may be up to 7 chars longer than pvlim.
+
+ char* pv_display(SV *dsv, const char *pv, STRLEN cur, STRLEN len, STRLEN pvlim)
+
+=for hackers
+Found in file dump.c
+
+=item pv_escape
+X<pv_escape>
+
+Escapes at most the first "count" chars of pv and puts the results into
+dsv such that the size of the escaped string will not exceed "max" chars
+and will not contain any incomplete escape sequences.
+
+If flags contains PERL_PV_ESCAPE_QUOTE then any double quotes in the string
+will also be escaped.
+
+Normally the SV will be cleared before the escaped string is prepared,
+but when PERL_PV_ESCAPE_NOCLEAR is set this will not occur.
+
+If PERL_PV_ESCAPE_UNI is set then the input string is treated as Unicode,
+if PERL_PV_ESCAPE_UNI_DETECT is set then the input string is scanned
+using C<is_utf8_string()> to determine if it is Unicode.
+
+If PERL_PV_ESCAPE_ALL is set then all input chars will be output
+using C<\x01F1> style escapes, otherwise only chars above 255 will be
+escaped using this style, other non printable chars will use octal or
+common escaped patterns like C<\n>. If PERL_PV_ESCAPE_NOBACKSLASH
+then all chars below 255 will be treated as printable and
+will be output as literals.
+
+If PERL_PV_ESCAPE_FIRSTCHAR is set then only the first char of the
+string will be escaped, regardles of max. If the string is utf8 and
+the chars value is >255 then it will be returned as a plain hex
+sequence. Thus the output will either be a single char,
+an octal escape sequence, a special escape like C<\n> or a 3 or
+more digit hex value.
+
+If PERL_PV_ESCAPE_RE is set then the escape char used will be a '%' and
+not a '\\'. This is because regexes very often contain backslashed
+sequences, whereas '%' is not a particularly common character in patterns.
+
+Returns a pointer to the escaped text as held by dsv.
+
+ char* pv_escape(SV *dsv, char const * const str, const STRLEN count, const STRLEN max, STRLEN * const escaped, const U32 flags)
+
+=for hackers
+Found in file dump.c
+
+=item pv_pretty
+X<pv_pretty>
+
+Converts a string into something presentable, handling escaping via
+pv_escape() and supporting quoting and ellipses.
+
+If the PERL_PV_PRETTY_QUOTE flag is set then the result will be
+double quoted with any double quotes in the string escaped. Otherwise
+if the PERL_PV_PRETTY_LTGT flag is set then the result be wrapped in
+angle brackets.
+
+If the PERL_PV_PRETTY_ELLIPSES flag is set and not all characters in
+string were output then an ellipsis C<...> will be appended to the
+string. Note that this happens AFTER it has been quoted.
+
+If start_color is non-null then it will be inserted after the opening
+quote (if there is one) but before the escaped text. If end_color
+is non-null then it will be inserted after the escaped text but before
+any quotes or ellipses.
+
+Returns a pointer to the prettified text as held by dsv.
+
+ char* pv_pretty(SV *dsv, char const * const str, const STRLEN count, const STRLEN max, char const * const start_color, char const * const end_color, const U32 flags)
+
+=for hackers
+Found in file dump.c
+
+
+=back
+
+=head1 Functions in file mathoms.c
+
+
+=over 8
+
+=item gv_fetchmethod
+X<gv_fetchmethod>
+
+See L<gv_fetchmethod_autoload>.
+
+ GV* gv_fetchmethod(HV* stash, const char* name)
+
+=for hackers
+Found in file mathoms.c
+
+=item pack_cat
+X<pack_cat>
+
+The engine implementing pack() Perl function. Note: parameters next_in_list and
+flags are not used. This call should not be used; use packlist instead.
+
+ void pack_cat(SV *cat, const char *pat, const char *patend, SV **beglist, SV **endlist, SV ***next_in_list, U32 flags)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_2pvbyte_nolen
+X<sv_2pvbyte_nolen>
+
+Return a pointer to the byte-encoded representation of the SV.
+May cause the SV to be downgraded from UTF-8 as a side-effect.
+
+Usually accessed via the C<SvPVbyte_nolen> macro.
+
+ char* sv_2pvbyte_nolen(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_2pvutf8_nolen
+X<sv_2pvutf8_nolen>
+
+Return a pointer to the UTF-8-encoded representation of the SV.
+May cause the SV to be upgraded to UTF-8 as a side-effect.
+
+Usually accessed via the C<SvPVutf8_nolen> macro.
+
+ char* sv_2pvutf8_nolen(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_2pv_nolen
+X<sv_2pv_nolen>
+
+Like C<sv_2pv()>, but doesn't return the length too. You should usually
+use the macro wrapper C<SvPV_nolen(sv)> instead.
+ char* sv_2pv_nolen(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_catpvn_mg
+X<sv_catpvn_mg>
+
+Like C<sv_catpvn>, but also handles 'set' magic.
+
+ void sv_catpvn_mg(SV *sv, const char *ptr, STRLEN len)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_catsv_mg
+X<sv_catsv_mg>
+
+Like C<sv_catsv>, but also handles 'set' magic.
+
+ void sv_catsv_mg(SV *dsv, SV *ssv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_force_normal
+X<sv_force_normal>
+
+Undo various types of fakery on an SV: if the PV is a shared string, make
+a private copy; if we're a ref, stop refing; if we're a glob, downgrade to
+an xpvmg. See also C<sv_force_normal_flags>.
+
+ void sv_force_normal(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_iv
+X<sv_iv>
+
+A private implementation of the C<SvIVx> macro for compilers which can't
+cope with complex macro expressions. Always use the macro instead.
+
+ IV sv_iv(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_nolocking
+X<sv_nolocking>
+
+Dummy routine which "locks" an SV when there is no locking module present.
+Exists to avoid test for a NULL function pointer and because it could
+potentially warn under some level of strict-ness.
+
+"Superseded" by sv_nosharing().
+
+ void sv_nolocking(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_nounlocking
+X<sv_nounlocking>
+
+Dummy routine which "unlocks" an SV when there is no locking module present.
+Exists to avoid test for a NULL function pointer and because it could
+potentially warn under some level of strict-ness.
+
+"Superseded" by sv_nosharing().
+
+ void sv_nounlocking(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_nv
+X<sv_nv>
+
+A private implementation of the C<SvNVx> macro for compilers which can't
+cope with complex macro expressions. Always use the macro instead.
+
+ NV sv_nv(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pv
+X<sv_pv>
+
+Use the C<SvPV_nolen> macro instead
+
+ char* sv_pv(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pvbyte
+X<sv_pvbyte>
+
+Use C<SvPVbyte_nolen> instead.
+
+ char* sv_pvbyte(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pvbyten
+X<sv_pvbyten>
+
+A private implementation of the C<SvPVbyte> macro for compilers
+which can't cope with complex macro expressions. Always use the macro
+instead.
+
+ char* sv_pvbyten(SV *sv, STRLEN *lp)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pvn
+X<sv_pvn>
+
+A private implementation of the C<SvPV> macro for compilers which can't
+cope with complex macro expressions. Always use the macro instead.
+
+ char* sv_pvn(SV *sv, STRLEN *lp)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pvutf8
+X<sv_pvutf8>
+
+Use the C<SvPVutf8_nolen> macro instead
+
+ char* sv_pvutf8(SV *sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_pvutf8n
+X<sv_pvutf8n>
+
+A private implementation of the C<SvPVutf8> macro for compilers
+which can't cope with complex macro expressions. Always use the macro
+instead.
+
+ char* sv_pvutf8n(SV *sv, STRLEN *lp)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_taint
+X<sv_taint>
+
+Taint an SV. Use C<SvTAINTED_on> instead.
+ void sv_taint(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_unref
+X<sv_unref>
+
+Unsets the RV status of the SV, and decrements the reference count of
+whatever was being referenced by the RV. This can almost be thought of
+as a reversal of C<newSVrv>. This is C<sv_unref_flags> with the C<flag>
+being zero. See C<SvROK_off>.
+
+ void sv_unref(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_usepvn
+X<sv_usepvn>
+
+Tells an SV to use C<ptr> to find its string value. Implemented by
+calling C<sv_usepvn_flags> with C<flags> of 0, hence does not handle 'set'
+magic. See C<sv_usepvn_flags>.
+
+ void sv_usepvn(SV* sv, char* ptr, STRLEN len)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_usepvn_mg
+X<sv_usepvn_mg>
+
+Like C<sv_usepvn>, but also handles 'set' magic.
+
+ void sv_usepvn_mg(SV *sv, char *ptr, STRLEN len)
+
+=for hackers
+Found in file mathoms.c
+
+=item sv_uv
+X<sv_uv>
+
+A private implementation of the C<SvUVx> macro for compilers which can't
+cope with complex macro expressions. Always use the macro instead.
+
+ UV sv_uv(SV* sv)
+
+=for hackers
+Found in file mathoms.c
+
+=item unpack_str
+X<unpack_str>
+
+The engine implementing unpack() Perl function. Note: parameters strbeg, new_s
+and ocnt are not used. This call should not be used, use unpackstring instead.
+
+ I32 unpack_str(const char *pat, const char *patend, const char *s, const char *strbeg, const char *strend, char **new_s, I32 ocnt, U32 flags)
+
+=for hackers
+Found in file mathoms.c
+
+
+=back
+
+=head1 Functions in file perl.h
+
+
+=over 8
+
+=item PERL_SYS_INIT
+X<PERL_SYS_INIT>
+
+Provides system-specific tune up of the C runtime environment necessary to
+run Perl interpreters. This should be called only once, before creating
+any Perl interpreters.
+
+ void PERL_SYS_INIT(int argc, char** argv)
+
+=for hackers
+Found in file perl.h
+
+=item PERL_SYS_INIT3
+X<PERL_SYS_INIT3>
+
+Provides system-specific tune up of the C runtime environment necessary to
+run Perl interpreters. This should be called only once, before creating
+any Perl interpreters.
+
+ void PERL_SYS_INIT3(int argc, char** argv, char** env)
+
+=for hackers
+Found in file perl.h
+
+=item PERL_SYS_TERM
+X<PERL_SYS_TERM>
+
+Provides system-specific clean up of the C runtime environment after
+running Perl interpreters. This should be called only once, after
+freeing any remaining Perl interpreters.
+
+ void PERL_SYS_TERM()
+
+=for hackers
+Found in file perl.h
+
+
+=back
+
+=head1 Functions in file pp_ctl.c
+
+
+=over 8
+
+=item find_runcv
+X<find_runcv>
+
+Locate the CV corresponding to the currently executing sub or eval.
+If db_seqp is non_null, skip CVs that are in the DB package and populate
+*db_seqp with the cop sequence number at the point that the DB:: code was
+entered. (allows debuggers to eval in the scope of the breakpoint rather
+than in the scope of the debugger itself).
+
+ CV* find_runcv(U32 *db_seqp)
+
+=for hackers
+Found in file pp_ctl.c
+
+
+=back
+
+=head1 Functions in file pp_pack.c
+
+
+=over 8
+
+=item packlist
+X<packlist>
+
+The engine implementing pack() Perl function.
+
+ void packlist(SV *cat, const char *pat, const char *patend, SV **beglist, SV **endlist)
+
+=for hackers
+Found in file pp_pack.c
+
+=item unpackstring
+X<unpackstring>
+
+The engine implementing unpack() Perl function. C<unpackstring> puts the
+extracted list items on the stack and returns the number of elements.
+Issue C<PUTBACK> before and C<SPAGAIN> after the call to this function.
+
+ I32 unpackstring(const char *pat, const char *patend, const char *s, const char *strend, U32 flags)
+
+=for hackers
+Found in file pp_pack.c
+
+
+=back
+
+=head1 Functions in file pp_sys.c
+
+
+=over 8
+
+=item setdefout
+X<setdefout>
+
+Sets PL_defoutgv, the default file handle for output, to the passed in
+typeglob. As PL_defoutgv "owns" a reference on its typeglob, the reference
+count of the passed in typeglob is increased by one, and the reference count
+of the typeglob that PL_defoutgv points to is decreased by one.
+
+ void setdefout(GV* gv)
+
+=for hackers
+Found in file pp_sys.c
+
+
+=back
+
+=head1 Global Variables
+
+=over 8
+
+=item PL_keyword_plugin
+X<PL_keyword_plugin>
+
+Function pointer, pointing at a function used to handle extended keywords.
+The function should be declared as
+
+ int keyword_plugin_function(pTHX_
+ char *keyword_ptr, STRLEN keyword_len,
+ OP **op_ptr)
+
+The function is called from the tokeniser, whenever a possible keyword
+is seen. C<keyword_ptr> points at the word in the parser's input
+buffer, and C<keyword_len> gives its length; it is not null-terminated.
+The function is expected to examine the word, and possibly other state
+such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
+as an extended keyword. If it does not, the function should return
+C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
+
+If the function wants to handle the keyword, it first must
+parse anything following the keyword that is part of the syntax
+introduced by the keyword. See L</Lexer interface> for details.
+
+When a keyword is being handled, the plugin function must build
+a tree of C<OP> structures, representing the code that was parsed.
+The root of the tree must be stored in C<*op_ptr>. The function then
+returns a contant indicating the syntactic role of the construct that
+it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
+C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
+construct cannot be used inside an expression (except via C<do BLOCK>
+and similar), and an expression is not a complete statement (it requires
+at least a terminating semicolon).
+
+When a keyword is handled, the plugin function may also have
+(compile-time) side effects. It may modify C<%^H>, define functions, and
+so on. Typically, if side effects are the main purpose of a handler,
+it does not wish to generate any ops to be included in the normal
+compilation. In this case it is still required to supply an op tree,
+but it suffices to generate a single null op.
+
+That's how the C<*PL_keyword_plugin> function needs to behave overall.
+Conventionally, however, one does not completely replace the existing
+handler function. Instead, take a copy of C<PL_keyword_plugin> before
+assigning your own function pointer to it. Your handler function should
+look for keywords that it is interested in and handle those. Where it
+is not interested, it should call the saved plugin function, passing on
+the arguments it received. Thus C<PL_keyword_plugin> actually points
+at a chain of handler functions, all of which have an opportunity to
+handle keywords, and only the last function in the chain (built into
+the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+=for hackers
+Found in file perlvars.h
+
+
+=back
+
+=head1 GV Functions
+
+=over 8
+
+=item GvSV
+X<GvSV>
+
+Return the SV from the GV.
+
+ SV* GvSV(GV* gv)
+
+=for hackers
+Found in file gv.h
+
+=item gv_const_sv
+X<gv_const_sv>
+
+If C<gv> is a typeglob whose subroutine entry is a constant sub eligible for
+inlining, or C<gv> is a placeholder reference that would be promoted to such
+a typeglob, then returns the value returned by the sub. Otherwise, returns
+NULL.
+
+ SV* gv_const_sv(GV* gv)
+
+=for hackers
+Found in file gv.c
+
+=item gv_fetchmeth
+X<gv_fetchmeth>
+
+Returns the glob with the given C<name> and a defined subroutine or
+C<NULL>. The glob lives in the given C<stash>, or in the stashes
+accessible via @ISA and UNIVERSAL::.
+
+The argument C<level> should be either 0 or -1. If C<level==0>, as a
+side-effect creates a glob with the given C<name> in the given C<stash>
+which in the case of success contains an alias for the subroutine, and sets
+up caching info for this glob.
+
+This function grants C<"SUPER"> token as a postfix of the stash name. The
+GV returned from C<gv_fetchmeth> may be a method cache entry, which is not
+visible to Perl code. So when calling C<call_sv>, you should not use
+the GV directly; instead, you should use the method's CV, which can be
+obtained from the GV with the C<GvCV> macro.
+
+ GV* gv_fetchmeth(HV* stash, const char* name, STRLEN len, I32 level)
+
+=for hackers
+Found in file gv.c
+
+=item gv_fetchmethod_autoload
+X<gv_fetchmethod_autoload>
+
+Returns the glob which contains the subroutine to call to invoke the method
+on the C<stash>. In fact in the presence of autoloading this may be the
+glob for "AUTOLOAD". In this case the corresponding variable $AUTOLOAD is
+already setup.
+
+The third parameter of C<gv_fetchmethod_autoload> determines whether
+AUTOLOAD lookup is performed if the given method is not present: non-zero
+means yes, look for AUTOLOAD; zero means no, don't look for AUTOLOAD.
+Calling C<gv_fetchmethod> is equivalent to calling C<gv_fetchmethod_autoload>
+with a non-zero C<autoload> parameter.
+
+These functions grant C<"SUPER"> token as a prefix of the method name. Note
+that if you want to keep the returned glob for a long time, you need to
+check for it being "AUTOLOAD", since at the later time the call may load a
+different subroutine due to $AUTOLOAD changing its value. Use the glob
+created via a side effect to do this.
+
+These functions have the same side-effects and as C<gv_fetchmeth> with
+C<level==0>. C<name> should be writable if contains C<':'> or C<'
+''>. The warning against passing the GV returned by C<gv_fetchmeth> to
+C<call_sv> apply equally to these functions.
+
+ GV* gv_fetchmethod_autoload(HV* stash, const char* name, I32 autoload)
+
+=for hackers
+Found in file gv.c
+
+=item gv_fetchmeth_autoload
+X<gv_fetchmeth_autoload>
+
+Same as gv_fetchmeth(), but looks for autoloaded subroutines too.
+Returns a glob for the subroutine.
+
+For an autoloaded subroutine without a GV, will create a GV even
+if C<level < 0>. For an autoloaded subroutine without a stub, GvCV()
+of the result may be zero.
+
+ GV* gv_fetchmeth_autoload(HV* stash, const char* name, STRLEN len, I32 level)
+
+=for hackers
+Found in file gv.c
+
+=item gv_stashpv
+X<gv_stashpv>
+
+Returns a pointer to the stash for a specified package. Uses C<strlen> to
+determine the length of C<name>, then calls C<gv_stashpvn()>.
+
+ HV* gv_stashpv(const char* name, I32 flags)
+
+=for hackers
+Found in file gv.c
+
+=item gv_stashpvn
+X<gv_stashpvn>
+
+Returns a pointer to the stash for a specified package. The C<namelen>
+parameter indicates the length of the C<name>, in bytes. C<flags> is passed
+to C<gv_fetchpvn_flags()>, so if set to C<GV_ADD> then the package will be
+created if it does not already exist. If the package does not exist and
+C<flags> is 0 (or any other setting that does not create packages) then NULL
+is returned.
+
+
+ HV* gv_stashpvn(const char* name, U32 namelen, I32 flags)
+
+=for hackers
+Found in file gv.c
+
+=item gv_stashpvs
+X<gv_stashpvs>
+
+Like C<gv_stashpvn>, but takes a literal string instead of a string/length pair.
+
+ HV* gv_stashpvs(const char* name, I32 create)
+
+=for hackers
+Found in file handy.h
+
+=item gv_stashsv
+X<gv_stashsv>
+
+Returns a pointer to the stash for a specified package. See C<gv_stashpvn>.
+
+ HV* gv_stashsv(SV* sv, I32 flags)
+
+=for hackers
+Found in file gv.c
+
+
+=back
+
+=head1 Handy Values
+
+=over 8
+
+=item Nullav
+X<Nullav>
+
+Null AV pointer.
+
+(deprecated - use C<(AV *)NULL> instead)
+
+=for hackers
+Found in file av.h
+
+=item Nullch
+X<Nullch>
+
+Null character pointer. (No longer available when C<PERL_CORE> is defined.)
+
+=for hackers
+Found in file handy.h
+
+=item Nullcv
+X<Nullcv>
+
+Null CV pointer.
+
+(deprecated - use C<(CV *)NULL> instead)
+
+=for hackers
+Found in file cv.h
+
+=item Nullhv
+X<Nullhv>
+
+Null HV pointer.
+
+(deprecated - use C<(HV *)NULL> instead)
+
+=for hackers
+Found in file hv.h
+
+=item Nullsv
+X<Nullsv>
+
+Null SV pointer. (No longer available when C<PERL_CORE> is defined.)
+
+=for hackers
+Found in file handy.h
+
+
+=back
+
+=head1 Hash Manipulation Functions
+
+=over 8
+
+=item get_hv
+X<get_hv>
+
+Returns the HV of the specified Perl hash. C<flags> are passed to
+C<gv_fetchpv>. If C<GV_ADD> is set and the
+Perl variable does not exist then it will be created. If C<flags> is zero
+and the variable does not exist then NULL is returned.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ HV* get_hv(const char *name, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item HEf_SVKEY
+X<HEf_SVKEY>
+
+This flag, used in the length slot of hash entries and magic structures,
+specifies the structure contains an C<SV*> pointer where a C<char*> pointer
+is to be expected. (For information only--not to be used).
+
+=for hackers
+Found in file hv.h
+
+=item HeHASH
+X<HeHASH>
+
+Returns the computed hash stored in the hash entry.
+
+ U32 HeHASH(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HeKEY
+X<HeKEY>
+
+Returns the actual pointer stored in the key slot of the hash entry. The
+pointer may be either C<char*> or C<SV*>, depending on the value of
+C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
+usually preferable for finding the value of a key.
+
+ void* HeKEY(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HeKLEN
+X<HeKLEN>
+
+If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
+holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
+be assigned to. The C<HePV()> macro is usually preferable for finding key
+lengths.
+
+ STRLEN HeKLEN(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HePV
+X<HePV>
+
+Returns the key slot of the hash entry as a C<char*> value, doing any
+necessary dereferencing of possibly C<SV*> keys. The length of the string
+is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
+not care about what the length of the key is, you may use the global
+variable C<PL_na>, though this is rather less efficient than using a local
+variable. Remember though, that hash keys in perl are free to contain
+embedded nulls, so using C<strlen()> or similar is not a good way to find
+the length of hash keys. This is very similar to the C<SvPV()> macro
+described elsewhere in this document. See also C<HeUTF8>.
+
+If you are using C<HePV> to get values to pass to C<newSVpvn()> to create a
+new SV, you should consider using C<newSVhek(HeKEY_hek(he))> as it is more
+efficient.
+
+ char* HePV(HE* he, STRLEN len)
+
+=for hackers
+Found in file hv.h
+
+=item HeSVKEY
+X<HeSVKEY>
+
+Returns the key as an C<SV*>, or C<NULL> if the hash entry does not
+contain an C<SV*> key.
+
+ SV* HeSVKEY(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HeSVKEY_force
+X<HeSVKEY_force>
+
+Returns the key as an C<SV*>. Will create and return a temporary mortal
+C<SV*> if the hash entry contains only a C<char*> key.
+
+ SV* HeSVKEY_force(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HeSVKEY_set
+X<HeSVKEY_set>
+
+Sets the key to a given C<SV*>, taking care to set the appropriate flags to
+indicate the presence of an C<SV*> key, and returns the same
+C<SV*>.
+
+ SV* HeSVKEY_set(HE* he, SV* sv)
+
+=for hackers
+Found in file hv.h
+
+=item HeUTF8
+X<HeUTF8>
+
+Returns whether the C<char *> value returned by C<HePV> is encoded in UTF-8,
+doing any necessary dereferencing of possibly C<SV*> keys. The value returned
+will be 0 or non-0, not necessarily 1 (or even a value with any low bits set),
+so B<do not> blindly assign this to a C<bool> variable, as C<bool> may be a
+typedef for C<char>.
+
+ char* HeUTF8(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HeVAL
+X<HeVAL>
+
+Returns the value slot (type C<SV*>) stored in the hash entry.
+
+ SV* HeVAL(HE* he)
+
+=for hackers
+Found in file hv.h
+
+=item HvNAME
+X<HvNAME>
+
+Returns the package name of a stash, or NULL if C<stash> isn't a stash.
+See C<SvSTASH>, C<CvSTASH>.
+
+ char* HvNAME(HV* stash)
+
+=for hackers
+Found in file hv.h
+
+=item hv_assert
+X<hv_assert>
+
+Check that a hash is in an internally consistent state.
+
+ void hv_assert(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_clear
+X<hv_clear>
+
+Clears a hash, making it empty.
+
+ void hv_clear(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_clear_placeholders
+X<hv_clear_placeholders>
+
+Clears any placeholders from a hash. If a restricted hash has any of its keys
+marked as readonly and the key is subsequently deleted, the key is not actually
+deleted but is marked by assigning it a value of &PL_sv_placeholder. This tags
+it so it will be ignored by future operations such as iterating over the hash,
+but will still allow the hash to have a value reassigned to the key at some
+future point. This function clears any such placeholder keys from the hash.
+See Hash::Util::lock_keys() for an example of its use.
+
+ void hv_clear_placeholders(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_delete
+X<hv_delete>
+
+Deletes a key/value pair in the hash. The value SV is removed from the
+hash and returned to the caller. The C<klen> is the length of the key.
+The C<flags> value will normally be zero; if set to G_DISCARD then NULL
+will be returned.
+
+ SV* hv_delete(HV *hv, const char *key, I32 klen, I32 flags)
+
+=for hackers
+Found in file hv.c
+
+=item hv_delete_ent
+X<hv_delete_ent>
+
+Deletes a key/value pair in the hash. The value SV is removed from the
+hash and returned to the caller. The C<flags> value will normally be zero;
+if set to G_DISCARD then NULL will be returned. C<hash> can be a valid
+precomputed hash value, or 0 to ask for it to be computed.
+
+ SV* hv_delete_ent(HV *hv, SV *keysv, I32 flags, U32 hash)
+
+=for hackers
+Found in file hv.c
+
+=item hv_exists
+X<hv_exists>
+
+Returns a boolean indicating whether the specified hash key exists. The
+C<klen> is the length of the key.
+
+ bool hv_exists(HV *hv, const char *key, I32 klen)
+
+=for hackers
+Found in file hv.c
+
+=item hv_exists_ent
+X<hv_exists_ent>
+
+Returns a boolean indicating whether the specified hash key exists. C<hash>
+can be a valid precomputed hash value, or 0 to ask for it to be
+computed.
+
+ bool hv_exists_ent(HV *hv, SV *keysv, U32 hash)
+
+=for hackers
+Found in file hv.c
+
+=item hv_fetch
+X<hv_fetch>
+
+Returns the SV which corresponds to the specified key in the hash. The
+C<klen> is the length of the key. If C<lval> is set then the fetch will be
+part of a store. Check that the return value is non-null before
+dereferencing it to an C<SV*>.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
+information on how to use this function on tied hashes.
+
+ SV** hv_fetch(HV *hv, const char *key, I32 klen, I32 lval)
+
+=for hackers
+Found in file hv.c
+
+=item hv_fetchs
+X<hv_fetchs>
+
+Like C<hv_fetch>, but takes a literal string instead of a string/length pair.
+
+ SV** hv_fetchs(HV* tb, const char* key, I32 lval)
+
+=for hackers
+Found in file handy.h
+
+=item hv_fetch_ent
+X<hv_fetch_ent>
+
+Returns the hash entry which corresponds to the specified key in the hash.
+C<hash> must be a valid precomputed hash number for the given C<key>, or 0
+if you want the function to compute it. IF C<lval> is set then the fetch
+will be part of a store. Make sure the return value is non-null before
+accessing it. The return value when C<tb> is a tied hash is a pointer to a
+static location, so be sure to make a copy of the structure if you need to
+store it somewhere.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
+information on how to use this function on tied hashes.
+
+ HE* hv_fetch_ent(HV *hv, SV *keysv, I32 lval, U32 hash)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iterinit
+X<hv_iterinit>
+
+Prepares a starting point to traverse a hash table. Returns the number of
+keys in the hash (i.e. the same as C<HvKEYS(tb)>). The return value is
+currently only meaningful for hashes without tie magic.
+
+NOTE: Before version 5.004_65, C<hv_iterinit> used to return the number of
+hash buckets that happen to be in use. If you still need that esoteric
+value, you can get it through the macro C<HvFILL(tb)>.
+
+
+ I32 hv_iterinit(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iterkey
+X<hv_iterkey>
+
+Returns the key from the current position of the hash iterator. See
+C<hv_iterinit>.
+
+ char* hv_iterkey(HE* entry, I32* retlen)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iterkeysv
+X<hv_iterkeysv>
+
+Returns the key as an C<SV*> from the current position of the hash
+iterator. The return value will always be a mortal copy of the key. Also
+see C<hv_iterinit>.
+
+ SV* hv_iterkeysv(HE* entry)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iternext
+X<hv_iternext>
+
+Returns entries from a hash iterator. See C<hv_iterinit>.
+
+You may call C<hv_delete> or C<hv_delete_ent> on the hash entry that the
+iterator currently points to, without losing your place or invalidating your
+iterator. Note that in this case the current entry is deleted from the hash
+with your iterator holding the last reference to it. Your iterator is flagged
+to free the entry on the next call to C<hv_iternext>, so you must not discard
+your iterator immediately else the entry will leak - call C<hv_iternext> to
+trigger the resource deallocation.
+
+ HE* hv_iternext(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iternextsv
+X<hv_iternextsv>
+
+Performs an C<hv_iternext>, C<hv_iterkey>, and C<hv_iterval> in one
+operation.
+
+ SV* hv_iternextsv(HV *hv, char **key, I32 *retlen)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iternext_flags
+X<hv_iternext_flags>
+
+Returns entries from a hash iterator. See C<hv_iterinit> and C<hv_iternext>.
+The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
+set the placeholders keys (for restricted hashes) will be returned in addition
+to normal keys. By default placeholders are automatically skipped over.
+Currently a placeholder is implemented with a value that is
+C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
+restricted hashes may change, and the implementation currently is
+insufficiently abstracted for any change to be tidy.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ HE* hv_iternext_flags(HV *hv, I32 flags)
+
+=for hackers
+Found in file hv.c
+
+=item hv_iterval
+X<hv_iterval>
+
+Returns the value from the current position of the hash iterator. See
+C<hv_iterkey>.
+
+ SV* hv_iterval(HV *hv, HE *entry)
+
+=for hackers
+Found in file hv.c
+
+=item hv_magic
+X<hv_magic>
+
+Adds magic to a hash. See C<sv_magic>.
+
+ void hv_magic(HV *hv, GV *gv, int how)
+
+=for hackers
+Found in file hv.c
+
+=item hv_scalar
+X<hv_scalar>
+
+Evaluates the hash in scalar context and returns the result. Handles magic when the hash is tied.
+
+ SV* hv_scalar(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item hv_store
+X<hv_store>
+
+Stores an SV in a hash. The hash key is specified as C<key> and C<klen> is
+the length of the key. The C<hash> parameter is the precomputed hash
+value; if it is zero then Perl will compute it. The return value will be
+NULL if the operation failed or if the value did not need to be actually
+stored within the hash (as in the case of tied hashes). Otherwise it can
+be dereferenced to get the original C<SV*>. Note that the caller is
+responsible for suitably incrementing the reference count of C<val> before
+the call, and decrementing it if the function returned NULL. Effectively
+a successful hv_store takes ownership of one reference to C<val>. This is
+usually what you want; a newly created SV has a reference count of one, so
+if all your code does is create SVs then store them in a hash, hv_store
+will own the only reference to the new SV, and your code doesn't need to do
+anything further to tidy up. hv_store is not implemented as a call to
+hv_store_ent, and does not create a temporary SV for the key, so if your
+key data is not already in SV form then use hv_store in preference to
+hv_store_ent.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
+information on how to use this function on tied hashes.
+
+ SV** hv_store(HV *hv, const char *key, I32 klen, SV *val, U32 hash)
+
+=for hackers
+Found in file hv.c
+
+=item hv_stores
+X<hv_stores>
+
+Like C<hv_store>, but takes a literal string instead of a string/length pair
+and omits the hash parameter.
+
+ SV** hv_stores(HV* tb, const char* key, NULLOK SV* val)
+
+=for hackers
+Found in file handy.h
+
+=item hv_store_ent
+X<hv_store_ent>
+
+Stores C<val> in a hash. The hash key is specified as C<key>. The C<hash>
+parameter is the precomputed hash value; if it is zero then Perl will
+compute it. The return value is the new hash entry so created. It will be
+NULL if the operation failed or if the value did not need to be actually
+stored within the hash (as in the case of tied hashes). Otherwise the
+contents of the return value can be accessed using the C<He?> macros
+described here. Note that the caller is responsible for suitably
+incrementing the reference count of C<val> before the call, and
+decrementing it if the function returned NULL. Effectively a successful
+hv_store_ent takes ownership of one reference to C<val>. This is
+usually what you want; a newly created SV has a reference count of one, so
+if all your code does is create SVs then store them in a hash, hv_store
+will own the only reference to the new SV, and your code doesn't need to do
+anything further to tidy up. Note that hv_store_ent only reads the C<key>;
+unlike C<val> it does not take ownership of it, so maintaining the correct
+reference count on C<key> is entirely the caller's responsibility. hv_store
+is not implemented as a call to hv_store_ent, and does not create a temporary
+SV for the key, so if your key data is not already in SV form then use
+hv_store in preference to hv_store_ent.
+
+See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for more
+information on how to use this function on tied hashes.
+
+ HE* hv_store_ent(HV *hv, SV *key, SV *val, U32 hash)
+
+=for hackers
+Found in file hv.c
+
+=item hv_undef
+X<hv_undef>
+
+Undefines the hash.
+
+ void hv_undef(HV *hv)
+
+=for hackers
+Found in file hv.c
+
+=item newHV
+X<newHV>
+
+Creates a new HV. The reference count is set to 1.
+
+ HV* newHV()
+
+=for hackers
+Found in file hv.h
+
+
+=back
+
+=head1 Lexer interface
+
+=over 8
+
+=item lex_bufutf8
+X<lex_bufutf8>
+
+Indicates whether the octets in the lexer buffer
+(L</PL_parser-E<gt>linestr>) should be interpreted as the UTF-8 encoding
+of Unicode characters. If not, they should be interpreted as Latin-1
+characters. This is analogous to the C<SvUTF8> flag for scalars.
+
+In UTF-8 mode, it is not guaranteed that the lexer buffer actually
+contains valid UTF-8. Lexing code must be robust in the face of invalid
+encoding.
+
+The actual C<SvUTF8> flag of the L</PL_parser-E<gt>linestr> scalar
+is significant, but not the whole story regarding the input character
+encoding. Normally, when a file is being read, the scalar contains octets
+and its C<SvUTF8> flag is off, but the octets should be interpreted as
+UTF-8 if the C<use utf8> pragma is in effect. During a string eval,
+however, the scalar may have the C<SvUTF8> flag on, and in this case its
+octets should be interpreted as UTF-8 unless the C<use bytes> pragma
+is in effect. This logic may change in the future; use this function
+instead of implementing the logic yourself.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ bool lex_bufutf8()
+
+=for hackers
+Found in file toke.c
+
+=item lex_discard_to
+X<lex_discard_to>
+
+Discards the first part of the L</PL_parser-E<gt>linestr> buffer,
+up to I<ptr>. The remaining content of the buffer will be moved, and
+all pointers into the buffer updated appropriately. I<ptr> must not
+be later in the buffer than the position of L</PL_parser-E<gt>bufptr>:
+it is not permitted to discard text that has yet to be lexed.
+
+Normally it is not necessarily to do this directly, because it suffices to
+use the implicit discarding behaviour of L</lex_next_chunk> and things
+based on it. However, if a token stretches across multiple lines,
+and the lexing code has kept multiple lines of text in the buffer fof
+that purpose, then after completion of the token it would be wise to
+explicitly discard the now-unneeded earlier lines, to avoid future
+multi-line tokens growing the buffer without bound.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_discard_to(char *ptr)
+
+=for hackers
+Found in file toke.c
+
+=item lex_grow_linestr
+X<lex_grow_linestr>
+
+Reallocates the lexer buffer (L</PL_parser-E<gt>linestr>) to accommodate
+at least I<len> octets (including terminating NUL). Returns a
+pointer to the reallocated buffer. This is necessary before making
+any direct modification of the buffer that would increase its length.
+L</lex_stuff_pvn> provides a more convenient way to insert text into
+the buffer.
+
+Do not use C<SvGROW> or C<sv_grow> directly on C<PL_parser-E<gt>linestr>;
+this function updates all of the lexer's variables that point directly
+into the buffer.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ char * lex_grow_linestr(STRLEN len)
+
+=for hackers
+Found in file toke.c
+
+=item lex_next_chunk
+X<lex_next_chunk>
+
+Reads in the next chunk of text to be lexed, appending it to
+L</PL_parser-E<gt>linestr>. This should be called when lexing code has
+looked to the end of the current chunk and wants to know more. It is
+usual, but not necessary, for lexing to have consumed the entirety of
+the current chunk at this time.
+
+If L</PL_parser-E<gt>bufptr> is pointing to the very end of the current
+chunk (i.e., the current chunk has been entirely consumed), normally the
+current chunk will be discarded at the same time that the new chunk is
+read in. If I<flags> includes C<LEX_KEEP_PREVIOUS>, the current chunk
+will not be discarded. If the current chunk has not been entirely
+consumed, then it will not be discarded regardless of the flag.
+
+Returns true if some new text was added to the buffer, or false if the
+buffer has reached the end of the input text.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ bool lex_next_chunk(U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_peek_unichar
+X<lex_peek_unichar>
+
+Looks ahead one (Unicode) character in the text currently being lexed.
+Returns the codepoint (unsigned integer value) of the next character,
+or -1 if lexing has reached the end of the input text. To consume the
+peeked character, use L</lex_read_unichar>.
+
+If the next character is in (or extends into) the next chunk of input
+text, the next chunk will be read in. Normally the current chunk will be
+discarded at the same time, but if I<flags> includes C<LEX_KEEP_PREVIOUS>
+then the current chunk will not be discarded.
+
+If the input is being interpreted as UTF-8 and a UTF-8 encoding error
+is encountered, an exception is generated.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ I32 lex_peek_unichar(U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_read_space
+X<lex_read_space>
+
+Reads optional spaces, in Perl style, in the text currently being
+lexed. The spaces may include ordinary whitespace characters and
+Perl-style comments. C<#line> directives are processed if encountered.
+L</PL_parser-E<gt>bufptr> is moved past the spaces, so that it points
+at a non-space character (or the end of the input text).
+
+If spaces extend into the next chunk of input text, the next chunk will
+be read in. Normally the current chunk will be discarded at the same
+time, but if I<flags> includes C<LEX_KEEP_PREVIOUS> then the current
+chunk will not be discarded.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_read_space(U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_read_to
+X<lex_read_to>
+
+Consume text in the lexer buffer, from L</PL_parser-E<gt>bufptr> up
+to I<ptr>. This advances L</PL_parser-E<gt>bufptr> to match I<ptr>,
+performing the correct bookkeeping whenever a newline character is passed.
+This is the normal way to consume lexed text.
+
+Interpretation of the buffer's octets can be abstracted out by
+using the slightly higher-level functions L</lex_peek_unichar> and
+L</lex_read_unichar>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_read_to(char *ptr)
+
+=for hackers
+Found in file toke.c
+
+=item lex_read_unichar
+X<lex_read_unichar>
+
+Reads the next (Unicode) character in the text currently being lexed.
+Returns the codepoint (unsigned integer value) of the character read,
+and moves L</PL_parser-E<gt>bufptr> past the character, or returns -1
+if lexing has reached the end of the input text. To non-destructively
+examine the next character, use L</lex_peek_unichar> instead.
+
+If the next character is in (or extends into) the next chunk of input
+text, the next chunk will be read in. Normally the current chunk will be
+discarded at the same time, but if I<flags> includes C<LEX_KEEP_PREVIOUS>
+then the current chunk will not be discarded.
+
+If the input is being interpreted as UTF-8 and a UTF-8 encoding error
+is encountered, an exception is generated.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ I32 lex_read_unichar(U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_stuff_pvn
+X<lex_stuff_pvn>
+
+Insert characters into the lexer buffer (L</PL_parser-E<gt>linestr>),
+immediately after the current lexing point (L</PL_parser-E<gt>bufptr>),
+reallocating the buffer if necessary. This means that lexing code that
+runs later will see the characters as if they had appeared in the input.
+It is not recommended to do this as part of normal parsing, and most
+uses of this facility run the risk of the inserted characters being
+interpreted in an unintended manner.
+
+The string to be inserted is represented by I<len> octets starting
+at I<pv>. These octets are interpreted as either UTF-8 or Latin-1,
+according to whether the C<LEX_STUFF_UTF8> flag is set in I<flags>.
+The characters are recoded for the lexer buffer, according to how the
+buffer is currently being interpreted (L</lex_bufutf8>). If a string
+to be interpreted is available as a Perl scalar, the L</lex_stuff_sv>
+function is more convenient.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_stuff_pvn(char *pv, STRLEN len, U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_stuff_sv
+X<lex_stuff_sv>
+
+Insert characters into the lexer buffer (L</PL_parser-E<gt>linestr>),
+immediately after the current lexing point (L</PL_parser-E<gt>bufptr>),
+reallocating the buffer if necessary. This means that lexing code that
+runs later will see the characters as if they had appeared in the input.
+It is not recommended to do this as part of normal parsing, and most
+uses of this facility run the risk of the inserted characters being
+interpreted in an unintended manner.
+
+The string to be inserted is the string value of I<sv>. The characters
+are recoded for the lexer buffer, according to how the buffer is currently
+being interpreted (L</lex_bufutf8>). If a string to be interpreted is
+not already a Perl scalar, the L</lex_stuff_pvn> function avoids the
+need to construct a scalar.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_stuff_sv(SV *sv, U32 flags)
+
+=for hackers
+Found in file toke.c
+
+=item lex_unstuff
+X<lex_unstuff>
+
+Discards text about to be lexed, from L</PL_parser-E<gt>bufptr> up to
+I<ptr>. Text following I<ptr> will be moved, and the buffer shortened.
+This hides the discarded text from any lexing code that runs later,
+as if the text had never appeared.
+
+This is not the normal way to consume lexed text. For that, use
+L</lex_read_to>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void lex_unstuff(char *ptr)
+
+=for hackers
+Found in file toke.c
+
+=item PL_parser
+X<PL_parser>
+
+Pointer to a structure encapsulating the state of the parsing operation
+currently in progress. The pointer can be locally changed to perform
+a nested parse without interfering with the state of an outer parse.
+Individual members of C<PL_parser> have their own documentation.
+
+=for hackers
+Found in file toke.c
+
+=item PL_parser-E<gt>bufend
+X<PL_parser-E<gt>bufend>
+
+Direct pointer to the end of the chunk of text currently being lexed, the
+end of the lexer buffer. This is equal to C<SvPVX(PL_parser-E<gt>linestr)
++ SvCUR(PL_parser-E<gt>linestr)>. A NUL character (zero octet) is
+always located at the end of the buffer, and does not count as part of
+the buffer's contents.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+=for hackers
+Found in file toke.c
+
+=item PL_parser-E<gt>bufptr
+X<PL_parser-E<gt>bufptr>
+
+Points to the current position of lexing inside the lexer buffer.
+Characters around this point may be freely examined, within
+the range delimited by C<SvPVX(L</PL_parser-E<gt>linestr>)> and
+L</PL_parser-E<gt>bufend>. The octets of the buffer may be intended to be
+interpreted as either UTF-8 or Latin-1, as indicated by L</lex_bufutf8>.
+
+Lexing code (whether in the Perl core or not) moves this pointer past
+the characters that it consumes. It is also expected to perform some
+bookkeeping whenever a newline character is consumed. This movement
+can be more conveniently performed by the function L</lex_read_to>,
+which handles newlines appropriately.
+
+Interpretation of the buffer's octets can be abstracted out by
+using the slightly higher-level functions L</lex_peek_unichar> and
+L</lex_read_unichar>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+=for hackers
+Found in file toke.c
+
+=item PL_parser-E<gt>linestart
+X<PL_parser-E<gt>linestart>
+
+Points to the start of the current line inside the lexer buffer.
+This is useful for indicating at which column an error occurred, and
+not much else. This must be updated by any lexing code that consumes
+a newline; the function L</lex_read_to> handles this detail.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+=for hackers
+Found in file toke.c
+
+=item PL_parser-E<gt>linestr
+X<PL_parser-E<gt>linestr>
+
+Buffer scalar containing the chunk currently under consideration of the
+text currently being lexed. This is always a plain string scalar (for
+which C<SvPOK> is true). It is not intended to be used as a scalar by
+normal scalar means; instead refer to the buffer directly by the pointer
+variables described below.
+
+The lexer maintains various C<char*> pointers to things in the
+C<PL_parser-E<gt>linestr> buffer. If C<PL_parser-E<gt>linestr> is ever
+reallocated, all of these pointers must be updated. Don't attempt to
+do this manually, but rather use L</lex_grow_linestr> if you need to
+reallocate the buffer.
+
+The content of the text chunk in the buffer is commonly exactly one
+complete line of input, up to and including a newline terminator,
+but there are situations where it is otherwise. The octets of the
+buffer may be intended to be interpreted as either UTF-8 or Latin-1.
+The function L</lex_bufutf8> tells you which. Do not use the C<SvUTF8>
+flag on this scalar, which may disagree with it.
+
+For direct examination of the buffer, the variable
+L</PL_parser-E<gt>bufend> points to the end of the buffer. The current
+lexing position is pointed to by L</PL_parser-E<gt>bufptr>. Direct use
+of these pointers is usually preferable to examination of the scalar
+through normal scalar means.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+=for hackers
+Found in file toke.c
+
+
+=back
+
+=head1 Magical Functions
+
+=over 8
+
+=item mg_clear
+X<mg_clear>
+
+Clear something magical that the SV represents. See C<sv_magic>.
+
+ int mg_clear(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item mg_copy
+X<mg_copy>
+
+Copies the magic from one SV to another. See C<sv_magic>.
+
+ int mg_copy(SV *sv, SV *nsv, const char *key, I32 klen)
+
+=for hackers
+Found in file mg.c
+
+=item mg_find
+X<mg_find>
+
+Finds the magic pointer for type matching the SV. See C<sv_magic>.
+
+ MAGIC* mg_find(const SV* sv, int type)
+
+=for hackers
+Found in file mg.c
+
+=item mg_free
+X<mg_free>
+
+Free any magic storage used by the SV. See C<sv_magic>.
+
+ int mg_free(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item mg_get
+X<mg_get>
+
+Do magic after a value is retrieved from the SV. See C<sv_magic>.
+
+ int mg_get(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item mg_length
+X<mg_length>
+
+Report on the SV's length. See C<sv_magic>.
+
+ U32 mg_length(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item mg_magical
+X<mg_magical>
+
+Turns on the magical status of an SV. See C<sv_magic>.
+
+ void mg_magical(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item mg_set
+X<mg_set>
+
+Do magic after a value is assigned to the SV. See C<sv_magic>.
+
+ int mg_set(SV* sv)
+
+=for hackers
+Found in file mg.c
+
+=item SvGETMAGIC
+X<SvGETMAGIC>
+
+Invokes C<mg_get> on an SV if it has 'get' magic. This macro evaluates its
+argument more than once.
+
+ void SvGETMAGIC(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvLOCK
+X<SvLOCK>
+
+Arranges for a mutual exclusion lock to be obtained on sv if a suitable module
+has been loaded.
+
+ void SvLOCK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSETMAGIC
+X<SvSETMAGIC>
+
+Invokes C<mg_set> on an SV if it has 'set' magic. This macro evaluates its
+argument more than once.
+
+ void SvSETMAGIC(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSetMagicSV
+X<SvSetMagicSV>
+
+Like C<SvSetSV>, but does any set magic required afterwards.
+
+ void SvSetMagicSV(SV* dsb, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSetMagicSV_nosteal
+X<SvSetMagicSV_nosteal>
+
+Like C<SvSetSV_nosteal>, but does any set magic required afterwards.
+
+ void SvSetMagicSV_nosteal(SV* dsv, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSetSV
+X<SvSetSV>
+
+Calls C<sv_setsv> if dsv is not the same as ssv. May evaluate arguments
+more than once.
+
+ void SvSetSV(SV* dsb, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSetSV_nosteal
+X<SvSetSV_nosteal>
+
+Calls a non-destructive version of C<sv_setsv> if dsv is not the same as
+ssv. May evaluate arguments more than once.
+
+ void SvSetSV_nosteal(SV* dsv, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSHARE
+X<SvSHARE>
+
+Arranges for sv to be shared between threads if a suitable module
+has been loaded.
+
+ void SvSHARE(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUNLOCK
+X<SvUNLOCK>
+
+Releases a mutual exclusion lock on sv if a suitable module
+has been loaded.
+
+ void SvUNLOCK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+
+=back
+
+=head1 Memory Management
+
+=over 8
+
+=item Copy
+X<Copy>
+
+The XSUB-writer's interface to the C C<memcpy> function. The C<src> is the
+source, C<dest> is the destination, C<nitems> is the number of items, and C<type> is
+the type. May fail on overlapping copies. See also C<Move>.
+
+ void Copy(void* src, void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item CopyD
+X<CopyD>
+
+Like C<Copy> but returns dest. Useful for encouraging compilers to tail-call
+optimise.
+
+ void * CopyD(void* src, void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item Move
+X<Move>
+
+The XSUB-writer's interface to the C C<memmove> function. The C<src> is the
+source, C<dest> is the destination, C<nitems> is the number of items, and C<type> is
+the type. Can do overlapping moves. See also C<Copy>.
+
+ void Move(void* src, void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item MoveD
+X<MoveD>
+
+Like C<Move> but returns dest. Useful for encouraging compilers to tail-call
+optimise.
+
+ void * MoveD(void* src, void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item Newx
+X<Newx>
+
+The XSUB-writer's interface to the C C<malloc> function.
+
+In 5.9.3, Newx() and friends replace the older New() API, and drops
+the first parameter, I<x>, a debug aid which allowed callers to identify
+themselves. This aid has been superseded by a new build option,
+PERL_MEM_LOG (see L<perlhack/PERL_MEM_LOG>). The older API is still
+there for use in XS modules supporting older perls.
+
+ void Newx(void* ptr, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item Newxc
+X<Newxc>
+
+The XSUB-writer's interface to the C C<malloc> function, with
+cast. See also C<Newx>.
+
+ void Newxc(void* ptr, int nitems, type, cast)
+
+=for hackers
+Found in file handy.h
+
+=item Newxz
+X<Newxz>
+
+The XSUB-writer's interface to the C C<malloc> function. The allocated
+memory is zeroed with C<memzero>. See also C<Newx>.
+
+ void Newxz(void* ptr, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item Poison
+X<Poison>
+
+PoisonWith(0xEF) for catching access to freed memory.
+
+ void Poison(void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item PoisonFree
+X<PoisonFree>
+
+PoisonWith(0xEF) for catching access to freed memory.
+
+ void PoisonFree(void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item PoisonNew
+X<PoisonNew>
+
+PoisonWith(0xAB) for catching access to allocated but uninitialized memory.
+
+ void PoisonNew(void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item PoisonWith
+X<PoisonWith>
+
+Fill up memory with a byte pattern (a byte repeated over and over
+again) that hopefully catches attempts to access uninitialized memory.
+
+ void PoisonWith(void* dest, int nitems, type, U8 byte)
+
+=for hackers
+Found in file handy.h
+
+=item Renew
+X<Renew>
+
+The XSUB-writer's interface to the C C<realloc> function.
+
+ void Renew(void* ptr, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item Renewc
+X<Renewc>
+
+The XSUB-writer's interface to the C C<realloc> function, with
+cast.
+
+ void Renewc(void* ptr, int nitems, type, cast)
+
+=for hackers
+Found in file handy.h
+
+=item Safefree
+X<Safefree>
+
+The XSUB-writer's interface to the C C<free> function.
+
+ void Safefree(void* ptr)
+
+=for hackers
+Found in file handy.h
+
+=item savepv
+X<savepv>
+
+Perl's version of C<strdup()>. Returns a pointer to a newly allocated
+string which is a duplicate of C<pv>. The size of the string is
+determined by C<strlen()>. The memory allocated for the new string can
+be freed with the C<Safefree()> function.
+
+ char* savepv(const char* pv)
+
+=for hackers
+Found in file util.c
+
+=item savepvn
+X<savepvn>
+
+Perl's version of what C<strndup()> would be if it existed. Returns a
+pointer to a newly allocated string which is a duplicate of the first
+C<len> bytes from C<pv>, plus a trailing NUL byte. The memory allocated for
+the new string can be freed with the C<Safefree()> function.
+
+ char* savepvn(const char* pv, I32 len)
+
+=for hackers
+Found in file util.c
+
+=item savepvs
+X<savepvs>
+
+Like C<savepvn>, but takes a literal string instead of a string/length pair.
+
+ char* savepvs(const char* s)
+
+=for hackers
+Found in file handy.h
+
+=item savesharedpv
+X<savesharedpv>
+
+A version of C<savepv()> which allocates the duplicate string in memory
+which is shared between threads.
+
+ char* savesharedpv(const char* pv)
+
+=for hackers
+Found in file util.c
+
+=item savesharedpvn
+X<savesharedpvn>
+
+A version of C<savepvn()> which allocates the duplicate string in memory
+which is shared between threads. (With the specific difference that a NULL
+pointer is not acceptable)
+
+ char* savesharedpvn(const char *const pv, const STRLEN len)
+
+=for hackers
+Found in file util.c
+
+=item savesvpv
+X<savesvpv>
+
+A version of C<savepv()>/C<savepvn()> which gets the string to duplicate from
+the passed in SV using C<SvPV()>
+
+ char* savesvpv(SV* sv)
+
+=for hackers
+Found in file util.c
+
+=item StructCopy
+X<StructCopy>
+
+This is an architecture-independent macro to copy one structure to another.
+
+ void StructCopy(type src, type dest, type)
+
+=for hackers
+Found in file handy.h
+
+=item Zero
+X<Zero>
+
+The XSUB-writer's interface to the C C<memzero> function. The C<dest> is the
+destination, C<nitems> is the number of items, and C<type> is the type.
+
+ void Zero(void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+=item ZeroD
+X<ZeroD>
+
+Like C<Zero> but returns dest. Useful for encouraging compilers to tail-call
+optimise.
+
+ void * ZeroD(void* dest, int nitems, type)
+
+=for hackers
+Found in file handy.h
+
+
+=back
+
+=head1 Miscellaneous Functions
+
+=over 8
+
+=item fbm_compile
+X<fbm_compile>
+
+Analyses the string in order to make fast searches on it using fbm_instr()
+-- the Boyer-Moore algorithm.
+
+ void fbm_compile(SV* sv, U32 flags)
+
+=for hackers
+Found in file util.c
+
+=item fbm_instr
+X<fbm_instr>
+
+Returns the location of the SV in the string delimited by C<str> and
+C<strend>. It returns C<NULL> if the string can't be found. The C<sv>
+does not have to be fbm_compiled, but the search will not be as fast
+then.
+
+ char* fbm_instr(unsigned char* big, unsigned char* bigend, SV* littlestr, U32 flags)
+
+=for hackers
+Found in file util.c
+
+=item form
+X<form>
+
+Takes a sprintf-style format pattern and conventional
+(non-SV) arguments and returns the formatted string.
+
+ (char *) Perl_form(pTHX_ const char* pat, ...)
+
+can be used any place a string (char *) is required:
+
+ char * s = Perl_form("%d.%d",major,minor);
+
+Uses a single private buffer so if you want to format several strings you
+must explicitly copy the earlier strings away (and free the copies when you
+are done).
+
+ char* form(const char* pat, ...)
+
+=for hackers
+Found in file util.c
+
+=item getcwd_sv
+X<getcwd_sv>
+
+Fill the sv with current working directory
+
+ int getcwd_sv(SV* sv)
+
+=for hackers
+Found in file util.c
+
+=item my_snprintf
+X<my_snprintf>
+
+The C library C<snprintf> functionality, if available and
+standards-compliant (uses C<vsnprintf>, actually). However, if the
+C<vsnprintf> is not available, will unfortunately use the unsafe
+C<vsprintf> which can overrun the buffer (there is an overrun check,
+but that may be too late). Consider using C<sv_vcatpvf> instead, or
+getting C<vsnprintf>.
+
+ int my_snprintf(char *buffer, const Size_t len, const char *format, ...)
+
+=for hackers
+Found in file util.c
+
+=item my_sprintf
+X<my_sprintf>
+
+The C library C<sprintf>, wrapped if necessary, to ensure that it will return
+the length of the string written to the buffer. Only rare pre-ANSI systems
+need the wrapper function - usually this is a direct call to C<sprintf>.
+
+ int my_sprintf(char *buffer, const char *pat, ...)
+
+=for hackers
+Found in file util.c
+
+=item my_vsnprintf
+X<my_vsnprintf>
+
+The C library C<vsnprintf> if available and standards-compliant.
+However, if if the C<vsnprintf> is not available, will unfortunately
+use the unsafe C<vsprintf> which can overrun the buffer (there is an
+overrun check, but that may be too late). Consider using
+C<sv_vcatpvf> instead, or getting C<vsnprintf>.
+
+ int my_vsnprintf(char *buffer, const Size_t len, const char *format, va_list ap)
+
+=for hackers
+Found in file util.c
+
+=item new_version
+X<new_version>
+
+Returns a new version object based on the passed in SV:
+
+ SV *sv = new_version(SV *ver);
+
+Does not alter the passed in ver SV. See "upg_version" if you
+want to upgrade the SV.
+
+ SV* new_version(SV *ver)
+
+=for hackers
+Found in file util.c
+
+=item prescan_version
+X<prescan_version>
+
+ const char* prescan_version(const char *s, bool strict, const char** errstr, bool *sqv, int *ssaw_decimal, int *swidth, bool *salpha)
+
+=for hackers
+Found in file util.c
+
+=item scan_version
+X<scan_version>
+
+Returns a pointer to the next character after the parsed
+version string, as well as upgrading the passed in SV to
+an RV.
+
+Function must be called with an already existing SV like
+
+ sv = newSV(0);
+ s = scan_version(s, SV *sv, bool qv);
+
+Performs some preprocessing to the string to ensure that
+it has the correct characteristics of a version. Flags the
+object if it contains an underscore (which denotes this
+is an alpha version). The boolean qv denotes that the version
+should be interpreted as if it had multiple decimals, even if
+it doesn't.
+
+ const char* scan_version(const char *s, SV *rv, bool qv)
+
+=for hackers
+Found in file util.c
+
+=item strEQ
+X<strEQ>
+
+Test two strings to see if they are equal. Returns true or false.
+
+ bool strEQ(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strGE
+X<strGE>
+
+Test two strings to see if the first, C<s1>, is greater than or equal to
+the second, C<s2>. Returns true or false.
+
+ bool strGE(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strGT
+X<strGT>
+
+Test two strings to see if the first, C<s1>, is greater than the second,
+C<s2>. Returns true or false.
+
+ bool strGT(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strLE
+X<strLE>
+
+Test two strings to see if the first, C<s1>, is less than or equal to the
+second, C<s2>. Returns true or false.
+
+ bool strLE(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strLT
+X<strLT>
+
+Test two strings to see if the first, C<s1>, is less than the second,
+C<s2>. Returns true or false.
+
+ bool strLT(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strNE
+X<strNE>
+
+Test two strings to see if they are different. Returns true or
+false.
+
+ bool strNE(char* s1, char* s2)
+
+=for hackers
+Found in file handy.h
+
+=item strnEQ
+X<strnEQ>
+
+Test two strings to see if they are equal. The C<len> parameter indicates
+the number of bytes to compare. Returns true or false. (A wrapper for
+C<strncmp>).
+
+ bool strnEQ(char* s1, char* s2, STRLEN len)
+
+=for hackers
+Found in file handy.h
+
+=item strnNE
+X<strnNE>
+
+Test two strings to see if they are different. The C<len> parameter
+indicates the number of bytes to compare. Returns true or false. (A
+wrapper for C<strncmp>).
+
+ bool strnNE(char* s1, char* s2, STRLEN len)
+
+=for hackers
+Found in file handy.h
+
+=item sv_destroyable
+X<sv_destroyable>
+
+Dummy routine which reports that object can be destroyed when there is no
+sharing module present. It ignores its single SV argument, and returns
+'true'. Exists to avoid test for a NULL function pointer and because it
+could potentially warn under some level of strict-ness.
+
+ bool sv_destroyable(SV *sv)
+
+=for hackers
+Found in file util.c
+
+=item sv_nosharing
+X<sv_nosharing>
+
+Dummy routine which "shares" an SV when there is no sharing module present.
+Or "locks" it. Or "unlocks" it. In other words, ignores its single SV argument.
+Exists to avoid test for a NULL function pointer and because it could
+potentially warn under some level of strict-ness.
+
+ void sv_nosharing(SV *sv)
+
+=for hackers
+Found in file util.c
+
+=item upg_version
+X<upg_version>
+
+In-place upgrade of the supplied SV to a version object.
+
+ SV *sv = upg_version(SV *sv, bool qv);
+
+Returns a pointer to the upgraded SV. Set the boolean qv if you want
+to force this SV to be interpreted as an "extended" version.
+
+ SV* upg_version(SV *ver, bool qv)
+
+=for hackers
+Found in file util.c
+
+=item vcmp
+X<vcmp>
+
+Version object aware cmp. Both operands must already have been
+converted into version objects.
+
+ int vcmp(SV *lhv, SV *rhv)
+
+=for hackers
+Found in file util.c
+
+=item vnormal
+X<vnormal>
+
+Accepts a version object and returns the normalized string
+representation. Call like:
+
+ sv = vnormal(rv);
+
+NOTE: you can pass either the object directly or the SV
+contained within the RV.
+
+ SV* vnormal(SV *vs)
+
+=for hackers
+Found in file util.c
+
+=item vnumify
+X<vnumify>
+
+Accepts a version object and returns the normalized floating
+point representation. Call like:
+
+ sv = vnumify(rv);
+
+NOTE: you can pass either the object directly or the SV
+contained within the RV.
+
+ SV* vnumify(SV *vs)
+
+=for hackers
+Found in file util.c
+
+=item vstringify
+X<vstringify>
+
+In order to maintain maximum compatibility with earlier versions
+of Perl, this function will return either the floating point
+notation or the multiple dotted notation, depending on whether
+the original version contained 1 or more dots, respectively
+
+ SV* vstringify(SV *vs)
+
+=for hackers
+Found in file util.c
+
+=item vverify
+X<vverify>
+
+Validates that the SV contains a valid version object.
+
+ bool vverify(SV *vobj);
+
+Note that it only confirms the bare minimum structure (so as not to get
+confused by derived classes which may contain additional hash entries):
+
+ bool vverify(SV *vs)
+
+=for hackers
+Found in file util.c
+
+
+=back
+
+=head1 MRO Functions
+
+=over 8
+
+=item mro_get_linear_isa
+X<mro_get_linear_isa>
+
+Returns either C<mro_get_linear_isa_c3> or
+C<mro_get_linear_isa_dfs> for the given stash,
+dependant upon which MRO is in effect
+for that stash. The return value is a
+read-only AV*.
+
+You are responsible for C<SvREFCNT_inc()> on the
+return value if you plan to store it anywhere
+semi-permanently (otherwise it might be deleted
+out from under you the next time the cache is
+invalidated).
+
+ AV* mro_get_linear_isa(HV* stash)
+
+=for hackers
+Found in file mro.c
+
+=item mro_method_changed_in
+X<mro_method_changed_in>
+
+Invalidates method caching on any child classes
+of the given stash, so that they might notice
+the changes in this one.
+
+Ideally, all instances of C<PL_sub_generation++> in
+perl source outside of C<mro.c> should be
+replaced by calls to this.
+
+Perl automatically handles most of the common
+ways a method might be redefined. However, there
+are a few ways you could change a method in a stash
+without the cache code noticing, in which case you
+need to call this method afterwards:
+
+1) Directly manipulating the stash HV entries from
+XS code.
+
+2) Assigning a reference to a readonly scalar
+constant into a stash entry in order to create
+a constant subroutine (like constant.pm
+does).
+
+This same method is available from pure perl
+via, C<mro::method_changed_in(classname)>.
+
+ void mro_method_changed_in(HV* stash)
+
+=for hackers
+Found in file mro.c
+
+
+=back
+
+=head1 Multicall Functions
+
+=over 8
+
+=item dMULTICALL
+X<dMULTICALL>
+
+Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
+
+ dMULTICALL;
+
+=for hackers
+Found in file cop.h
+
+=item MULTICALL
+X<MULTICALL>
+
+Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
+
+ MULTICALL;
+
+=for hackers
+Found in file cop.h
+
+=item POP_MULTICALL
+X<POP_MULTICALL>
+
+Closing bracket for a lightweight callback.
+See L<perlcall/Lightweight Callbacks>.
+
+ POP_MULTICALL;
+
+=for hackers
+Found in file cop.h
+
+=item PUSH_MULTICALL
+X<PUSH_MULTICALL>
+
+Opening bracket for a lightweight callback.
+See L<perlcall/Lightweight Callbacks>.
+
+ PUSH_MULTICALL;
+
+=for hackers
+Found in file cop.h
+
+
+=back
+
+=head1 Numeric functions
+
+=over 8
+
+=item grok_bin
+X<grok_bin>
+
+converts a string representing a binary number to numeric form.
+
+On entry I<start> and I<*len> give the string to scan, I<*flags> gives
+conversion flags, and I<result> should be NULL or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
+invalid character will also trigger a warning.
+On return I<*len> is set to the length of the scanned string,
+and I<*flags> gives output flags.
+
+If the value is <= C<UV_MAX> it is returned as a UV, the output flags are clear,
+and nothing is written to I<*result>. If the value is > UV_MAX C<grok_bin>
+returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to I<*result> (or the value is discarded if I<result>
+is NULL).
+
+The binary number may optionally be prefixed with "0b" or "b" unless
+C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If
+C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the binary
+number may use '_' characters to separate digits.
+
+ UV grok_bin(const char* start, STRLEN* len_p, I32* flags, NV *result)
+
+=for hackers
+Found in file numeric.c
+
+=item grok_hex
+X<grok_hex>
+
+converts a string representing a hex number to numeric form.
+
+On entry I<start> and I<*len> give the string to scan, I<*flags> gives
+conversion flags, and I<result> should be NULL or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
+invalid character will also trigger a warning.
+On return I<*len> is set to the length of the scanned string,
+and I<*flags> gives output flags.
+
+If the value is <= UV_MAX it is returned as a UV, the output flags are clear,
+and nothing is written to I<*result>. If the value is > UV_MAX C<grok_hex>
+returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to I<*result> (or the value is discarded if I<result>
+is NULL).
+
+The hex number may optionally be prefixed with "0x" or "x" unless
+C<PERL_SCAN_DISALLOW_PREFIX> is set in I<*flags> on entry. If
+C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the hex
+number may use '_' characters to separate digits.
+
+ UV grok_hex(const char* start, STRLEN* len_p, I32* flags, NV *result)
+
+=for hackers
+Found in file numeric.c
+
+=item grok_number
+X<grok_number>
+
+Recognise (or not) a number. The type of the number is returned
+(0 if unrecognised), otherwise it is a bit-ORed combination of
+IS_NUMBER_IN_UV, IS_NUMBER_GREATER_THAN_UV_MAX, IS_NUMBER_NOT_INT,
+IS_NUMBER_NEG, IS_NUMBER_INFINITY, IS_NUMBER_NAN (defined in perl.h).
+
+If the value of the number can fit an in UV, it is returned in the *valuep
+IS_NUMBER_IN_UV will be set to indicate that *valuep is valid, IS_NUMBER_IN_UV
+will never be set unless *valuep is valid, but *valuep may have been assigned
+to during processing even though IS_NUMBER_IN_UV is not set on return.
+If valuep is NULL, IS_NUMBER_IN_UV will be set for the same cases as when
+valuep is non-NULL, but no actual assignment (or SEGV) will occur.
+
+IS_NUMBER_NOT_INT will be set with IS_NUMBER_IN_UV if trailing decimals were
+seen (in which case *valuep gives the true value truncated to an integer), and
+IS_NUMBER_NEG if the number is negative (in which case *valuep holds the
+absolute value). IS_NUMBER_IN_UV is not set if e notation was used or the
+number is larger than a UV.
+
+ int grok_number(const char *pv, STRLEN len, UV *valuep)
+
+=for hackers
+Found in file numeric.c
+
+=item grok_numeric_radix
+X<grok_numeric_radix>
+
+Scan and skip for a numeric decimal separator (radix).
+
+ bool grok_numeric_radix(const char **sp, const char *send)
+
+=for hackers
+Found in file numeric.c
+
+=item grok_oct
+X<grok_oct>
+
+converts a string representing an octal number to numeric form.
+
+On entry I<start> and I<*len> give the string to scan, I<*flags> gives
+conversion flags, and I<result> should be NULL or a pointer to an NV.
+The scan stops at the end of the string, or the first invalid character.
+Unless C<PERL_SCAN_SILENT_ILLDIGIT> is set in I<*flags>, encountering an
+invalid character will also trigger a warning.
+On return I<*len> is set to the length of the scanned string,
+and I<*flags> gives output flags.
+
+If the value is <= UV_MAX it is returned as a UV, the output flags are clear,
+and nothing is written to I<*result>. If the value is > UV_MAX C<grok_oct>
+returns UV_MAX, sets C<PERL_SCAN_GREATER_THAN_UV_MAX> in the output flags,
+and writes the value to I<*result> (or the value is discarded if I<result>
+is NULL).
+
+If C<PERL_SCAN_ALLOW_UNDERSCORES> is set in I<*flags> then the octal
+number may use '_' characters to separate digits.
+
+ UV grok_oct(const char* start, STRLEN* len_p, I32* flags, NV *result)
+
+=for hackers
+Found in file numeric.c
+
+=item Perl_signbit
+X<Perl_signbit>
+
+Return a non-zero integer if the sign bit on an NV is set, and 0 if
+it is not.
+
+If Configure detects this system has a signbit() that will work with
+our NVs, then we just use it via the #define in perl.h. Otherwise,
+fall back on this implementation. As a first pass, this gets everything
+right except -0.0. Alas, catching -0.0 is the main use for this function,
+so this is not too helpful yet. Still, at least we have the scaffolding
+in place to support other systems, should that prove useful.
+
+
+Configure notes: This function is called 'Perl_signbit' instead of a
+plain 'signbit' because it is easy to imagine a system having a signbit()
+function or macro that doesn't happen to work with our particular choice
+of NVs. We shouldn't just re-#define signbit as Perl_signbit and expect
+the standard system headers to be happy. Also, this is a no-context
+function (no pTHX_) because Perl_signbit() is usually re-#defined in
+perl.h as a simple macro call to the system's signbit().
+Users should just always call Perl_signbit().
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ int Perl_signbit(NV f)
+
+=for hackers
+Found in file numeric.c
+
+=item scan_bin
+X<scan_bin>
+
+For backwards compatibility. Use C<grok_bin> instead.
+
+ NV scan_bin(const char* start, STRLEN len, STRLEN* retlen)
+
+=for hackers
+Found in file numeric.c
+
+=item scan_hex
+X<scan_hex>
+
+For backwards compatibility. Use C<grok_hex> instead.
+
+ NV scan_hex(const char* start, STRLEN len, STRLEN* retlen)
+
+=for hackers
+Found in file numeric.c
+
+=item scan_oct
+X<scan_oct>
+
+For backwards compatibility. Use C<grok_oct> instead.
+
+ NV scan_oct(const char* start, STRLEN len, STRLEN* retlen)
+
+=for hackers
+Found in file numeric.c
+
+
+=back
+
+=head1 Optree Manipulation Functions
+
+=over 8
+
+=item cv_const_sv
+X<cv_const_sv>
+
+If C<cv> is a constant sub eligible for inlining. returns the constant
+value returned by the sub. Otherwise, returns NULL.
+
+Constant subs can be created with C<newCONSTSUB> or as described in
+L<perlsub/"Constant Functions">.
+
+ SV* cv_const_sv(const CV *const cv)
+
+=for hackers
+Found in file op.c
+
+=item newCONSTSUB
+X<newCONSTSUB>
+
+Creates a constant sub equivalent to Perl C<sub FOO () { 123 }> which is
+eligible for inlining at compile-time.
+
+Passing NULL for SV creates a constant sub equivalent to C<sub BAR () {}>,
+which won't be called if used as a destructor, but will suppress the overhead
+of a call to C<AUTOLOAD>. (This form, however, isn't eligible for inlining at
+compile time.)
+
+ CV* newCONSTSUB(HV* stash, const char* name, SV* sv)
+
+=for hackers
+Found in file op.c
+
+=item newXS
+X<newXS>
+
+Used by C<xsubpp> to hook up XSUBs as Perl subs. I<filename> needs to be
+static storage, as it is used directly as CvFILE(), without a copy being made.
+
+=for hackers
+Found in file op.c
+
+
+=back
+
+=head1 Pad Data Structures
+
+=over 8
+
+=item pad_findmy
+X<pad_findmy>
+
+Given a lexical name, try to find its offset, first in the current pad,
+or failing that, in the pads of any lexically enclosing subs (including
+the complications introduced by eval). If the name is found in an outer pad,
+then a fake entry is added to the current pad.
+Returns the offset in the current pad, or NOT_IN_PAD on failure.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ PADOFFSET pad_findmy(const char* name, STRLEN len, U32 flags)
+
+=for hackers
+Found in file pad.c
+
+=item pad_sv
+X<pad_sv>
+
+Get the value at offset po in the current pad.
+Use macro PAD_SV instead of calling this function directly.
+
+ SV* pad_sv(PADOFFSET po)
+
+=for hackers
+Found in file pad.c
+
+
+=back
+
+=head1 Per-Interpreter Variables
+
+=over 8
+
+=item PL_modglobal
+X<PL_modglobal>
+
+C<PL_modglobal> is a general purpose, interpreter global HV for use by
+extensions that need to keep information on a per-interpreter basis.
+In a pinch, it can also be used as a symbol table for extensions
+to share data among each other. It is a good idea to use keys
+prefixed by the package name of the extension that owns the data.
+
+ HV* PL_modglobal
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_na
+X<PL_na>
+
+A convenience variable which is typically used with C<SvPV> when one
+doesn't care about the length of the string. It is usually more efficient
+to either declare a local variable and use that instead or to use the
+C<SvPV_nolen> macro.
+
+ STRLEN PL_na
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_opfreehook
+X<PL_opfreehook>
+
+When non-C<NULL>, the function pointed by this variable will be called each time an OP is freed with the corresponding OP as the argument.
+This allows extensions to free any extra attribute they have locally attached to an OP.
+It is also assured to first fire for the parent OP and then for its kids.
+
+When you replace this variable, it is considered a good practice to store the possibly previously installed hook and that you recall it inside your own.
+
+ Perl_ophook_t PL_opfreehook
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_sv_no
+X<PL_sv_no>
+
+This is the C<false> SV. See C<PL_sv_yes>. Always refer to this as
+C<&PL_sv_no>.
+
+ SV PL_sv_no
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_sv_undef
+X<PL_sv_undef>
+
+This is the C<undef> SV. Always refer to this as C<&PL_sv_undef>.
+
+ SV PL_sv_undef
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_sv_yes
+X<PL_sv_yes>
+
+This is the C<true> SV. See C<PL_sv_no>. Always refer to this as
+C<&PL_sv_yes>.
+
+ SV PL_sv_yes
+
+=for hackers
+Found in file intrpvar.h
+
+
+=back
+
+=head1 REGEXP Functions
+
+=over 8
+
+=item SvRX
+X<SvRX>
+
+Convenience macro to get the REGEXP from a SV. This is approximately
+equivalent to the following snippet:
+
+ if (SvMAGICAL(sv))
+ mg_get(sv);
+ if (SvROK(sv) &&
+ (tmpsv = (SV*)SvRV(sv)) &&
+ SvTYPE(tmpsv) == SVt_PVMG &&
+ (tmpmg = mg_find(tmpsv, PERL_MAGIC_qr)))
+ {
+ return (REGEXP *)tmpmg->mg_obj;
+ }
+
+NULL will be returned if a REGEXP* is not found.
+
+ REGEXP * SvRX(SV *sv)
+
+=for hackers
+Found in file regexp.h
+
+=item SvRXOK
+X<SvRXOK>
+
+Returns a boolean indicating whether the SV contains qr magic
+(PERL_MAGIC_qr).
+
+If you want to do something with the REGEXP* later use SvRX instead
+and check for NULL.
+
+ bool SvRXOK(SV* sv)
+
+=for hackers
+Found in file regexp.h
+
+
+=back
+
+=head1 Simple Exception Handling Macros
+
+=over 8
+
+=item dXCPT
+X<dXCPT>
+
+Set up necessary local variables for exception handling.
+See L<perlguts/"Exception Handling">.
+
+ dXCPT;
+
+=for hackers
+Found in file XSUB.h
+
+=item XCPT_CATCH
+X<XCPT_CATCH>
+
+Introduces a catch block. See L<perlguts/"Exception Handling">.
+
+=for hackers
+Found in file XSUB.h
+
+=item XCPT_RETHROW
+X<XCPT_RETHROW>
+
+Rethrows a previously caught exception. See L<perlguts/"Exception Handling">.
+
+ XCPT_RETHROW;
+
+=for hackers
+Found in file XSUB.h
+
+=item XCPT_TRY_END
+X<XCPT_TRY_END>
+
+Ends a try block. See L<perlguts/"Exception Handling">.
+
+=for hackers
+Found in file XSUB.h
+
+=item XCPT_TRY_START
+X<XCPT_TRY_START>
+
+Starts a try block. See L<perlguts/"Exception Handling">.
+
+=for hackers
+Found in file XSUB.h
+
+
+=back
+
+=head1 Stack Manipulation Macros
+
+=over 8
+
+=item dMARK
+X<dMARK>
+
+Declare a stack marker variable, C<mark>, for the XSUB. See C<MARK> and
+C<dORIGMARK>.
+
+ dMARK;
+
+=for hackers
+Found in file pp.h
+
+=item dORIGMARK
+X<dORIGMARK>
+
+Saves the original stack mark for the XSUB. See C<ORIGMARK>.
+
+ dORIGMARK;
+
+=for hackers
+Found in file pp.h
+
+=item dSP
+X<dSP>
+
+Declares a local copy of perl's stack pointer for the XSUB, available via
+the C<SP> macro. See C<SP>.
+
+ dSP;
+
+=for hackers
+Found in file pp.h
+
+=item EXTEND
+X<EXTEND>
+
+Used to extend the argument stack for an XSUB's return values. Once
+used, guarantees that there is room for at least C<nitems> to be pushed
+onto the stack.
+
+ void EXTEND(SP, int nitems)
+
+=for hackers
+Found in file pp.h
+
+=item MARK
+X<MARK>
+
+Stack marker variable for the XSUB. See C<dMARK>.
+
+=for hackers
+Found in file pp.h
+
+=item mPUSHi
+X<mPUSHi>
+
+Push an integer onto the stack. The stack must have room for this element.
+Does not use C<TARG>. See also C<PUSHi>, C<mXPUSHi> and C<XPUSHi>.
+
+ void mPUSHi(IV iv)
+
+=for hackers
+Found in file pp.h
+
+=item mPUSHn
+X<mPUSHn>
+
+Push a double onto the stack. The stack must have room for this element.
+Does not use C<TARG>. See also C<PUSHn>, C<mXPUSHn> and C<XPUSHn>.
+
+ void mPUSHn(NV nv)
+
+=for hackers
+Found in file pp.h
+
+=item mPUSHp
+X<mPUSHp>
+
+Push a string onto the stack. The stack must have room for this element.
+The C<len> indicates the length of the string. Does not use C<TARG>.
+See also C<PUSHp>, C<mXPUSHp> and C<XPUSHp>.
+
+ void mPUSHp(char* str, STRLEN len)
+
+=for hackers
+Found in file pp.h
+
+=item mPUSHs
+X<mPUSHs>
+
+Push an SV onto the stack and mortalizes the SV. The stack must have room
+for this element. Does not use C<TARG>. See also C<PUSHs> and C<mXPUSHs>.
+
+ void mPUSHs(SV* sv)
+
+=for hackers
+Found in file pp.h
+
+=item mPUSHu
+X<mPUSHu>
+
+Push an unsigned integer onto the stack. The stack must have room for this
+element. Does not use C<TARG>. See also C<PUSHu>, C<mXPUSHu> and C<XPUSHu>.
+
+ void mPUSHu(UV uv)
+
+=for hackers
+Found in file pp.h
+
+=item mXPUSHi
+X<mXPUSHi>
+
+Push an integer onto the stack, extending the stack if necessary.
+Does not use C<TARG>. See also C<XPUSHi>, C<mPUSHi> and C<PUSHi>.
+
+ void mXPUSHi(IV iv)
+
+=for hackers
+Found in file pp.h
+
+=item mXPUSHn
+X<mXPUSHn>
+
+Push a double onto the stack, extending the stack if necessary.
+Does not use C<TARG>. See also C<XPUSHn>, C<mPUSHn> and C<PUSHn>.
+
+ void mXPUSHn(NV nv)
+
+=for hackers
+Found in file pp.h
+
+=item mXPUSHp
+X<mXPUSHp>
+
+Push a string onto the stack, extending the stack if necessary. The C<len>
+indicates the length of the string. Does not use C<TARG>. See also C<XPUSHp>,
+C<mPUSHp> and C<PUSHp>.
+
+ void mXPUSHp(char* str, STRLEN len)
+
+=for hackers
+Found in file pp.h
+
+=item mXPUSHs
+X<mXPUSHs>
+
+Push an SV onto the stack, extending the stack if necessary and mortalizes
+the SV. Does not use C<TARG>. See also C<XPUSHs> and C<mPUSHs>.
+
+ void mXPUSHs(SV* sv)
+
+=for hackers
+Found in file pp.h
+
+=item mXPUSHu
+X<mXPUSHu>
+
+Push an unsigned integer onto the stack, extending the stack if necessary.
+Does not use C<TARG>. See also C<XPUSHu>, C<mPUSHu> and C<PUSHu>.
+
+ void mXPUSHu(UV uv)
+
+=for hackers
+Found in file pp.h
+
+=item ORIGMARK
+X<ORIGMARK>
+
+The original stack mark for the XSUB. See C<dORIGMARK>.
+
+=for hackers
+Found in file pp.h
+
+=item POPi
+X<POPi>
+
+Pops an integer off the stack.
+
+ IV POPi
+
+=for hackers
+Found in file pp.h
+
+=item POPl
+X<POPl>
+
+Pops a long off the stack.
+
+ long POPl
+
+=for hackers
+Found in file pp.h
+
+=item POPn
+X<POPn>
+
+Pops a double off the stack.
+
+ NV POPn
+
+=for hackers
+Found in file pp.h
+
+=item POPp
+X<POPp>
+
+Pops a string off the stack. Deprecated. New code should use POPpx.
+
+ char* POPp
+
+=for hackers
+Found in file pp.h
+
+=item POPpbytex
+X<POPpbytex>
+
+Pops a string off the stack which must consist of bytes i.e. characters < 256.
+
+ char* POPpbytex
+
+=for hackers
+Found in file pp.h
+
+=item POPpx
+X<POPpx>
+
+Pops a string off the stack.
+
+ char* POPpx
+
+=for hackers
+Found in file pp.h
+
+=item POPs
+X<POPs>
+
+Pops an SV off the stack.
+
+ SV* POPs
+
+=for hackers
+Found in file pp.h
+
+=item PUSHi
+X<PUSHi>
+
+Push an integer onto the stack. The stack must have room for this element.
+Handles 'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it. Do not call multiple C<TARG>-oriented macros to
+return lists from XSUB's - see C<mPUSHi> instead. See also C<XPUSHi> and
+C<mXPUSHi>.
+
+ void PUSHi(IV iv)
+
+=for hackers
+Found in file pp.h
+
+=item PUSHMARK
+X<PUSHMARK>
+
+Opening bracket for arguments on a callback. See C<PUTBACK> and
+L<perlcall>.
+
+ void PUSHMARK(SP)
+
+=for hackers
+Found in file pp.h
+
+=item PUSHmortal
+X<PUSHmortal>
+
+Push a new mortal SV onto the stack. The stack must have room for this
+element. Does not use C<TARG>. See also C<PUSHs>, C<XPUSHmortal> and C<XPUSHs>.
+
+ void PUSHmortal()
+
+=for hackers
+Found in file pp.h
+
+=item PUSHn
+X<PUSHn>
+
+Push a double onto the stack. The stack must have room for this element.
+Handles 'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it. Do not call multiple C<TARG>-oriented macros to
+return lists from XSUB's - see C<mPUSHn> instead. See also C<XPUSHn> and
+C<mXPUSHn>.
+
+ void PUSHn(NV nv)
+
+=for hackers
+Found in file pp.h
+
+=item PUSHp
+X<PUSHp>
+
+Push a string onto the stack. The stack must have room for this element.
+The C<len> indicates the length of the string. Handles 'set' magic. Uses
+C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to declare it. Do not
+call multiple C<TARG>-oriented macros to return lists from XSUB's - see
+C<mPUSHp> instead. See also C<XPUSHp> and C<mXPUSHp>.
+
+ void PUSHp(char* str, STRLEN len)
+
+=for hackers
+Found in file pp.h
+
+=item PUSHs
+X<PUSHs>
+
+Push an SV onto the stack. The stack must have room for this element.
+Does not handle 'set' magic. Does not use C<TARG>. See also C<PUSHmortal>,
+C<XPUSHs> and C<XPUSHmortal>.
+
+ void PUSHs(SV* sv)
+
+=for hackers
+Found in file pp.h
+
+=item PUSHu
+X<PUSHu>
+
+Push an unsigned integer onto the stack. The stack must have room for this
+element. Handles 'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG>
+should be called to declare it. Do not call multiple C<TARG>-oriented
+macros to return lists from XSUB's - see C<mPUSHu> instead. See also
+C<XPUSHu> and C<mXPUSHu>.
+
+ void PUSHu(UV uv)
+
+=for hackers
+Found in file pp.h
+
+=item PUTBACK
+X<PUTBACK>
+
+Closing bracket for XSUB arguments. This is usually handled by C<xsubpp>.
+See C<PUSHMARK> and L<perlcall> for other uses.
+
+ PUTBACK;
+
+=for hackers
+Found in file pp.h
+
+=item SP
+X<SP>
+
+Stack pointer. This is usually handled by C<xsubpp>. See C<dSP> and
+C<SPAGAIN>.
+
+=for hackers
+Found in file pp.h
+
+=item SPAGAIN
+X<SPAGAIN>
+
+Refetch the stack pointer. Used after a callback. See L<perlcall>.
+
+ SPAGAIN;
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHi
+X<XPUSHi>
+
+Push an integer onto the stack, extending the stack if necessary. Handles
+'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to
+declare it. Do not call multiple C<TARG>-oriented macros to return lists
+from XSUB's - see C<mXPUSHi> instead. See also C<PUSHi> and C<mPUSHi>.
+
+ void XPUSHi(IV iv)
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHmortal
+X<XPUSHmortal>
+
+Push a new mortal SV onto the stack, extending the stack if necessary.
+Does not use C<TARG>. See also C<XPUSHs>, C<PUSHmortal> and C<PUSHs>.
+
+ void XPUSHmortal()
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHn
+X<XPUSHn>
+
+Push a double onto the stack, extending the stack if necessary. Handles
+'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to
+declare it. Do not call multiple C<TARG>-oriented macros to return lists
+from XSUB's - see C<mXPUSHn> instead. See also C<PUSHn> and C<mPUSHn>.
+
+ void XPUSHn(NV nv)
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHp
+X<XPUSHp>
+
+Push a string onto the stack, extending the stack if necessary. The C<len>
+indicates the length of the string. Handles 'set' magic. Uses C<TARG>, so
+C<dTARGET> or C<dXSTARG> should be called to declare it. Do not call
+multiple C<TARG>-oriented macros to return lists from XSUB's - see
+C<mXPUSHp> instead. See also C<PUSHp> and C<mPUSHp>.
+
+ void XPUSHp(char* str, STRLEN len)
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHs
+X<XPUSHs>
+
+Push an SV onto the stack, extending the stack if necessary. Does not
+handle 'set' magic. Does not use C<TARG>. See also C<XPUSHmortal>,
+C<PUSHs> and C<PUSHmortal>.
+
+ void XPUSHs(SV* sv)
+
+=for hackers
+Found in file pp.h
+
+=item XPUSHu
+X<XPUSHu>
+
+Push an unsigned integer onto the stack, extending the stack if necessary.
+Handles 'set' magic. Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it. Do not call multiple C<TARG>-oriented macros to
+return lists from XSUB's - see C<mXPUSHu> instead. See also C<PUSHu> and
+C<mPUSHu>.
+
+ void XPUSHu(UV uv)
+
+=for hackers
+Found in file pp.h
+
+=item XSRETURN
+X<XSRETURN>
+
+Return from XSUB, indicating number of items on the stack. This is usually
+handled by C<xsubpp>.
+
+ void XSRETURN(int nitems)
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_EMPTY
+X<XSRETURN_EMPTY>
+
+Return an empty list from an XSUB immediately.
+
+ XSRETURN_EMPTY;
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_IV
+X<XSRETURN_IV>
+
+Return an integer from an XSUB immediately. Uses C<XST_mIV>.
+
+ void XSRETURN_IV(IV iv)
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_NO
+X<XSRETURN_NO>
+
+Return C<&PL_sv_no> from an XSUB immediately. Uses C<XST_mNO>.
+
+ XSRETURN_NO;
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_NV
+X<XSRETURN_NV>
+
+Return a double from an XSUB immediately. Uses C<XST_mNV>.
+
+ void XSRETURN_NV(NV nv)
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_PV
+X<XSRETURN_PV>
+
+Return a copy of a string from an XSUB immediately. Uses C<XST_mPV>.
+
+ void XSRETURN_PV(char* str)
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_UNDEF
+X<XSRETURN_UNDEF>
+
+Return C<&PL_sv_undef> from an XSUB immediately. Uses C<XST_mUNDEF>.
+
+ XSRETURN_UNDEF;
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_UV
+X<XSRETURN_UV>
+
+Return an integer from an XSUB immediately. Uses C<XST_mUV>.
+
+ void XSRETURN_UV(IV uv)
+
+=for hackers
+Found in file XSUB.h
+
+=item XSRETURN_YES
+X<XSRETURN_YES>
+
+Return C<&PL_sv_yes> from an XSUB immediately. Uses C<XST_mYES>.
+
+ XSRETURN_YES;
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mIV
+X<XST_mIV>
+
+Place an integer into the specified position C<pos> on the stack. The
+value is stored in a new mortal SV.
+
+ void XST_mIV(int pos, IV iv)
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mNO
+X<XST_mNO>
+
+Place C<&PL_sv_no> into the specified position C<pos> on the
+stack.
+
+ void XST_mNO(int pos)
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mNV
+X<XST_mNV>
+
+Place a double into the specified position C<pos> on the stack. The value
+is stored in a new mortal SV.
+
+ void XST_mNV(int pos, NV nv)
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mPV
+X<XST_mPV>
+
+Place a copy of a string into the specified position C<pos> on the stack.
+The value is stored in a new mortal SV.
+
+ void XST_mPV(int pos, char* str)
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mUNDEF
+X<XST_mUNDEF>
+
+Place C<&PL_sv_undef> into the specified position C<pos> on the
+stack.
+
+ void XST_mUNDEF(int pos)
+
+=for hackers
+Found in file XSUB.h
+
+=item XST_mYES
+X<XST_mYES>
+
+Place C<&PL_sv_yes> into the specified position C<pos> on the
+stack.
+
+ void XST_mYES(int pos)
+
+=for hackers
+Found in file XSUB.h
+
+
+=back
+
+=head1 SV Flags
+
+=over 8
+
+=item svtype
+X<svtype>
+
+An enum of flags for Perl types. These are found in the file B<sv.h>
+in the C<svtype> enum. Test these flags with the C<SvTYPE> macro.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_IV
+X<SVt_IV>
+
+Integer type flag for scalars. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_NV
+X<SVt_NV>
+
+Double type flag for scalars. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_PV
+X<SVt_PV>
+
+Pointer type flag for scalars. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_PVAV
+X<SVt_PVAV>
+
+Type flag for arrays. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_PVCV
+X<SVt_PVCV>
+
+Type flag for code refs. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_PVHV
+X<SVt_PVHV>
+
+Type flag for hashes. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+=item SVt_PVMG
+X<SVt_PVMG>
+
+Type flag for blessed scalars. See C<svtype>.
+
+=for hackers
+Found in file sv.h
+
+
+=back
+
+=head1 SV Manipulation Functions
+
+=over 8
+
+=item croak_xs_usage
+X<croak_xs_usage>
+
+A specialised variant of C<croak()> for emitting the usage message for xsubs
+
+ croak_xs_usage(cv, "eee_yow");
+
+works out the package name and subroutine name from C<cv>, and then calls
+C<croak()>. Hence if C<cv> is C<&ouch::awk>, it would call C<croak> as:
+
+ Perl_croak(aTHX_ "Usage %s::%s(%s)", "ouch" "awk", "eee_yow");
+
+ void croak_xs_usage(const CV *const cv, const char *const params)
+
+=for hackers
+Found in file universal.c
+
+=item get_sv
+X<get_sv>
+
+Returns the SV of the specified Perl scalar. C<flags> are passed to
+C<gv_fetchpv>. If C<GV_ADD> is set and the
+Perl variable does not exist then it will be created. If C<flags> is zero
+and the variable does not exist then NULL is returned.
+
+NOTE: the perl_ form of this function is deprecated.
+
+ SV* get_sv(const char *name, I32 flags)
+
+=for hackers
+Found in file perl.c
+
+=item newRV_inc
+X<newRV_inc>
+
+Creates an RV wrapper for an SV. The reference count for the original SV is
+incremented.
+
+ SV* newRV_inc(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item newSVpvn_utf8
+X<newSVpvn_utf8>
+
+Creates a new SV and copies a string into it. If utf8 is true, calls
+C<SvUTF8_on> on the new SV. Implemented as a wrapper around C<newSVpvn_flags>.
+
+ SV* newSVpvn_utf8(NULLOK const char* s, STRLEN len, U32 utf8)
+
+=for hackers
+Found in file sv.h
+
+=item SvCUR
+X<SvCUR>
+
+Returns the length of the string which is in the SV. See C<SvLEN>.
+
+ STRLEN SvCUR(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvCUR_set
+X<SvCUR_set>
+
+Set the current length of the string which is in the SV. See C<SvCUR>
+and C<SvIV_set>.
+
+ void SvCUR_set(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvEND
+X<SvEND>
+
+Returns a pointer to the last character in the string which is in the SV.
+See C<SvCUR>. Access the character as *(SvEND(sv)).
+
+ char* SvEND(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvGAMAGIC
+X<SvGAMAGIC>
+
+Returns true if the SV has get magic or overloading. If either is true then
+the scalar is active data, and has the potential to return a new value every
+time it is accessed. Hence you must be careful to only read it once per user
+logical operation and work with that returned value. If neither is true then
+the scalar's value cannot change unless written to.
+
+ U32 SvGAMAGIC(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvGROW
+X<SvGROW>
+
+Expands the character buffer in the SV so that it has room for the
+indicated number of bytes (remember to reserve space for an extra trailing
+NUL character). Calls C<sv_grow> to perform the expansion if necessary.
+Returns a pointer to the character buffer.
+
+ char * SvGROW(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK
+X<SvIOK>
+
+Returns a U32 value indicating whether the SV contains an integer.
+
+ U32 SvIOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOKp
+X<SvIOKp>
+
+Returns a U32 value indicating whether the SV contains an integer. Checks
+the B<private> setting. Use C<SvIOK> instead.
+
+ U32 SvIOKp(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_notUV
+X<SvIOK_notUV>
+
+Returns a boolean indicating whether the SV contains a signed integer.
+
+ bool SvIOK_notUV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_off
+X<SvIOK_off>
+
+Unsets the IV status of an SV.
+
+ void SvIOK_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_on
+X<SvIOK_on>
+
+Tells an SV that it is an integer.
+
+ void SvIOK_on(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_only
+X<SvIOK_only>
+
+Tells an SV that it is an integer and disables all other OK bits.
+
+ void SvIOK_only(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_only_UV
+X<SvIOK_only_UV>
+
+Tells and SV that it is an unsigned integer and disables all other OK bits.
+
+ void SvIOK_only_UV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIOK_UV
+X<SvIOK_UV>
+
+Returns a boolean indicating whether the SV contains an unsigned integer.
+
+ bool SvIOK_UV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIsCOW
+X<SvIsCOW>
+
+Returns a boolean indicating whether the SV is Copy-On-Write. (either shared
+hash key scalars, or full Copy On Write scalars if 5.9.0 is configured for
+COW)
+
+ bool SvIsCOW(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIsCOW_shared_hash
+X<SvIsCOW_shared_hash>
+
+Returns a boolean indicating whether the SV is Copy-On-Write shared hash key
+scalar.
+
+ bool SvIsCOW_shared_hash(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIV
+X<SvIV>
+
+Coerces the given SV to an integer and returns it. See C<SvIVx> for a
+version which guarantees to evaluate sv only once.
+
+ IV SvIV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIVX
+X<SvIVX>
+
+Returns the raw value in the SV's IV slot, without checks or conversions.
+Only use when you are sure SvIOK is true. See also C<SvIV()>.
+
+ IV SvIVX(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIVx
+X<SvIVx>
+
+Coerces the given SV to an integer and returns it. Guarantees to evaluate
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvIV>.
+
+ IV SvIVx(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIV_nomg
+X<SvIV_nomg>
+
+Like C<SvIV> but doesn't process magic.
+
+ IV SvIV_nomg(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvIV_set
+X<SvIV_set>
+
+Set the value of the IV pointer in sv to val. It is possible to perform
+the same function of this macro with an lvalue assignment to C<SvIVX>.
+With future Perls, however, it will be more efficient to use
+C<SvIV_set> instead of the lvalue assignment to C<SvIVX>.
+
+ void SvIV_set(SV* sv, IV val)
+
+=for hackers
+Found in file sv.h
+
+=item SvLEN
+X<SvLEN>
+
+Returns the size of the string buffer in the SV, not including any part
+attributable to C<SvOOK>. See C<SvCUR>.
+
+ STRLEN SvLEN(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvLEN_set
+X<SvLEN_set>
+
+Set the actual length of the string which is in the SV. See C<SvIV_set>.
+
+ void SvLEN_set(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvMAGIC_set
+X<SvMAGIC_set>
+
+Set the value of the MAGIC pointer in sv to val. See C<SvIV_set>.
+
+ void SvMAGIC_set(SV* sv, MAGIC* val)
+
+=for hackers
+Found in file sv.h
+
+=item SvNIOK
+X<SvNIOK>
+
+Returns a U32 value indicating whether the SV contains a number, integer or
+double.
+
+ U32 SvNIOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNIOKp
+X<SvNIOKp>
+
+Returns a U32 value indicating whether the SV contains a number, integer or
+double. Checks the B<private> setting. Use C<SvNIOK> instead.
+
+ U32 SvNIOKp(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNIOK_off
+X<SvNIOK_off>
+
+Unsets the NV/IV status of an SV.
+
+ void SvNIOK_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNOK
+X<SvNOK>
+
+Returns a U32 value indicating whether the SV contains a double.
+
+ U32 SvNOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNOKp
+X<SvNOKp>
+
+Returns a U32 value indicating whether the SV contains a double. Checks the
+B<private> setting. Use C<SvNOK> instead.
+
+ U32 SvNOKp(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNOK_off
+X<SvNOK_off>
+
+Unsets the NV status of an SV.
+
+ void SvNOK_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNOK_on
+X<SvNOK_on>
+
+Tells an SV that it is a double.
+
+ void SvNOK_on(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNOK_only
+X<SvNOK_only>
+
+Tells an SV that it is a double and disables all other OK bits.
+
+ void SvNOK_only(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNV
+X<SvNV>
+
+Coerce the given SV to a double and return it. See C<SvNVx> for a version
+which guarantees to evaluate sv only once.
+
+ NV SvNV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNVX
+X<SvNVX>
+
+Returns the raw value in the SV's NV slot, without checks or conversions.
+Only use when you are sure SvNOK is true. See also C<SvNV()>.
+
+ NV SvNVX(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNVx
+X<SvNVx>
+
+Coerces the given SV to a double and returns it. Guarantees to evaluate
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvNV>.
+
+ NV SvNVx(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvNV_set
+X<SvNV_set>
+
+Set the value of the NV pointer in sv to val. See C<SvIV_set>.
+
+ void SvNV_set(SV* sv, NV val)
+
+=for hackers
+Found in file sv.h
+
+=item SvOK
+X<SvOK>
+
+Returns a U32 value indicating whether the value is defined. This is
+only meaningful for scalars.
+
+ U32 SvOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvOOK
+X<SvOOK>
+
+Returns a U32 indicating whether the pointer to the string buffer is offset.
+This hack is used internally to speed up removal of characters from the
+beginning of a SvPV. When SvOOK is true, then the start of the
+allocated string buffer is actually C<SvOOK_offset()> bytes before SvPVX.
+This offset used to be stored in SvIVX, but is now stored within the spare
+part of the buffer.
+
+ U32 SvOOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvOOK_offset
+X<SvOOK_offset>
+
+Reads into I<len> the offset from SvPVX back to the true start of the
+allocated buffer, which will be non-zero if C<sv_chop> has been used to
+efficiently remove characters from start of the buffer. Implemented as a
+macro, which takes the address of I<len>, which must be of type C<STRLEN>.
+Evaluates I<sv> more than once. Sets I<len> to 0 if C<SvOOK(sv)> is false.
+
+ void SvOOK_offset(NN SV*sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOK
+X<SvPOK>
+
+Returns a U32 value indicating whether the SV contains a character
+string.
+
+ U32 SvPOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOKp
+X<SvPOKp>
+
+Returns a U32 value indicating whether the SV contains a character string.
+Checks the B<private> setting. Use C<SvPOK> instead.
+
+ U32 SvPOKp(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOK_off
+X<SvPOK_off>
+
+Unsets the PV status of an SV.
+
+ void SvPOK_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOK_on
+X<SvPOK_on>
+
+Tells an SV that it is a string.
+
+ void SvPOK_on(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOK_only
+X<SvPOK_only>
+
+Tells an SV that it is a string and disables all other OK bits.
+Will also turn off the UTF-8 status.
+
+ void SvPOK_only(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPOK_only_UTF8
+X<SvPOK_only_UTF8>
+
+Tells an SV that it is a string and disables all other OK bits,
+and leaves the UTF-8 status as it was.
+
+ void SvPOK_only_UTF8(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV
+X<SvPV>
+
+Returns a pointer to the string in the SV, or a stringified form of
+the SV if the SV does not contain a string. The SV may cache the
+stringified version becoming C<SvPOK>. Handles 'get' magic. See also
+C<SvPVx> for a version which guarantees to evaluate sv only once.
+
+ char* SvPV(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVbyte
+X<SvPVbyte>
+
+Like C<SvPV>, but converts sv to byte representation first if necessary.
+
+ char* SvPVbyte(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVbytex
+X<SvPVbytex>
+
+Like C<SvPV>, but converts sv to byte representation first if necessary.
+Guarantees to evaluate sv only once; use the more efficient C<SvPVbyte>
+otherwise.
+
+ char* SvPVbytex(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVbytex_force
+X<SvPVbytex_force>
+
+Like C<SvPV_force>, but converts sv to byte representation first if necessary.
+Guarantees to evaluate sv only once; use the more efficient C<SvPVbyte_force>
+otherwise.
+
+ char* SvPVbytex_force(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVbyte_force
+X<SvPVbyte_force>
+
+Like C<SvPV_force>, but converts sv to byte representation first if necessary.
+
+ char* SvPVbyte_force(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVbyte_nolen
+X<SvPVbyte_nolen>
+
+Like C<SvPV_nolen>, but converts sv to byte representation first if necessary.
+
+ char* SvPVbyte_nolen(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVutf8
+X<SvPVutf8>
+
+Like C<SvPV>, but converts sv to utf8 first if necessary.
+
+ char* SvPVutf8(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVutf8x
+X<SvPVutf8x>
+
+Like C<SvPV>, but converts sv to utf8 first if necessary.
+Guarantees to evaluate sv only once; use the more efficient C<SvPVutf8>
+otherwise.
+
+ char* SvPVutf8x(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVutf8x_force
+X<SvPVutf8x_force>
+
+Like C<SvPV_force>, but converts sv to utf8 first if necessary.
+Guarantees to evaluate sv only once; use the more efficient C<SvPVutf8_force>
+otherwise.
+
+ char* SvPVutf8x_force(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVutf8_force
+X<SvPVutf8_force>
+
+Like C<SvPV_force>, but converts sv to utf8 first if necessary.
+
+ char* SvPVutf8_force(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVutf8_nolen
+X<SvPVutf8_nolen>
+
+Like C<SvPV_nolen>, but converts sv to utf8 first if necessary.
+
+ char* SvPVutf8_nolen(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVX
+X<SvPVX>
+
+Returns a pointer to the physical string in the SV. The SV must contain a
+string.
+
+ char* SvPVX(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPVx
+X<SvPVx>
+
+A version of C<SvPV> which guarantees to evaluate C<sv> only once.
+Only use this if C<sv> is an expression with side effects, otherwise use the
+more efficient C<SvPVX>.
+
+ char* SvPVx(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV_force
+X<SvPV_force>
+
+Like C<SvPV> but will force the SV into containing just a string
+(C<SvPOK_only>). You want force if you are going to update the C<SvPVX>
+directly.
+
+ char* SvPV_force(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV_force_nomg
+X<SvPV_force_nomg>
+
+Like C<SvPV> but will force the SV into containing just a string
+(C<SvPOK_only>). You want force if you are going to update the C<SvPVX>
+directly. Doesn't process magic.
+
+ char* SvPV_force_nomg(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV_nolen
+X<SvPV_nolen>
+
+Returns a pointer to the string in the SV, or a stringified form of
+the SV if the SV does not contain a string. The SV may cache the
+stringified form becoming C<SvPOK>. Handles 'get' magic.
+
+ char* SvPV_nolen(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV_nomg
+X<SvPV_nomg>
+
+Like C<SvPV> but doesn't process magic.
+
+ char* SvPV_nomg(SV* sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item SvPV_set
+X<SvPV_set>
+
+Set the value of the PV pointer in sv to val. See C<SvIV_set>.
+
+ void SvPV_set(SV* sv, char* val)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT
+X<SvREFCNT>
+
+Returns the value of the object's reference count.
+
+ U32 SvREFCNT(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_dec
+X<SvREFCNT_dec>
+
+Decrements the reference count of the given SV.
+
+ void SvREFCNT_dec(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc
+X<SvREFCNT_inc>
+
+Increments the reference count of the given SV.
+
+All of the following SvREFCNT_inc* macros are optimized versions of
+SvREFCNT_inc, and can be replaced with SvREFCNT_inc.
+
+ SV* SvREFCNT_inc(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_NN
+X<SvREFCNT_inc_NN>
+
+Same as SvREFCNT_inc, but can only be used if you know I<sv>
+is not NULL. Since we don't have to check the NULLness, it's faster
+and smaller.
+
+ SV* SvREFCNT_inc_NN(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_simple
+X<SvREFCNT_inc_simple>
+
+Same as SvREFCNT_inc, but can only be used with expressions without side
+effects. Since we don't have to store a temporary value, it's faster.
+
+ SV* SvREFCNT_inc_simple(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_simple_NN
+X<SvREFCNT_inc_simple_NN>
+
+Same as SvREFCNT_inc_simple, but can only be used if you know I<sv>
+is not NULL. Since we don't have to check the NULLness, it's faster
+and smaller.
+
+ SV* SvREFCNT_inc_simple_NN(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_simple_void
+X<SvREFCNT_inc_simple_void>
+
+Same as SvREFCNT_inc_simple, but can only be used if you don't need the
+return value. The macro doesn't need to return a meaningful value.
+
+ void SvREFCNT_inc_simple_void(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_simple_void_NN
+X<SvREFCNT_inc_simple_void_NN>
+
+Same as SvREFCNT_inc, but can only be used if you don't need the return
+value, and you know that I<sv> is not NULL. The macro doesn't need
+to return a meaningful value, or check for NULLness, so it's smaller
+and faster.
+
+ void SvREFCNT_inc_simple_void_NN(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_void
+X<SvREFCNT_inc_void>
+
+Same as SvREFCNT_inc, but can only be used if you don't need the
+return value. The macro doesn't need to return a meaningful value.
+
+ void SvREFCNT_inc_void(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvREFCNT_inc_void_NN
+X<SvREFCNT_inc_void_NN>
+
+Same as SvREFCNT_inc, but can only be used if you don't need the return
+value, and you know that I<sv> is not NULL. The macro doesn't need
+to return a meaningful value, or check for NULLness, so it's smaller
+and faster.
+
+ void SvREFCNT_inc_void_NN(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvROK
+X<SvROK>
+
+Tests if the SV is an RV.
+
+ U32 SvROK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvROK_off
+X<SvROK_off>
+
+Unsets the RV status of an SV.
+
+ void SvROK_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvROK_on
+X<SvROK_on>
+
+Tells an SV that it is an RV.
+
+ void SvROK_on(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvRV
+X<SvRV>
+
+Dereferences an RV to return the SV.
+
+ SV* SvRV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvRV_set
+X<SvRV_set>
+
+Set the value of the RV pointer in sv to val. See C<SvIV_set>.
+
+ void SvRV_set(SV* sv, SV* val)
+
+=for hackers
+Found in file sv.h
+
+=item SvSTASH
+X<SvSTASH>
+
+Returns the stash of the SV.
+
+ HV* SvSTASH(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvSTASH_set
+X<SvSTASH_set>
+
+Set the value of the STASH pointer in sv to val. See C<SvIV_set>.
+
+ void SvSTASH_set(SV* sv, HV* val)
+
+=for hackers
+Found in file sv.h
+
+=item SvTAINT
+X<SvTAINT>
+
+Taints an SV if tainting is enabled.
+
+ void SvTAINT(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvTAINTED
+X<SvTAINTED>
+
+Checks to see if an SV is tainted. Returns TRUE if it is, FALSE if
+not.
+
+ bool SvTAINTED(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvTAINTED_off
+X<SvTAINTED_off>
+
+Untaints an SV. Be I<very> careful with this routine, as it short-circuits
+some of Perl's fundamental security features. XS module authors should not
+use this function unless they fully understand all the implications of
+unconditionally untainting the value. Untainting should be done in the
+standard perl fashion, via a carefully crafted regexp, rather than directly
+untainting variables.
+
+ void SvTAINTED_off(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvTAINTED_on
+X<SvTAINTED_on>
+
+Marks an SV as tainted if tainting is enabled.
+
+ void SvTAINTED_on(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvTRUE
+X<SvTRUE>
+
+Returns a boolean indicating whether Perl would evaluate the SV as true or
+false. See SvOK() for a defined/undefined test. Does not handle 'get' magic.
+
+ bool SvTRUE(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvTYPE
+X<SvTYPE>
+
+Returns the type of the SV. See C<svtype>.
+
+ svtype SvTYPE(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUOK
+X<SvUOK>
+
+Returns a boolean indicating whether the SV contains an unsigned integer.
+
+ bool SvUOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUPGRADE
+X<SvUPGRADE>
+
+Used to upgrade an SV to a more complex form. Uses C<sv_upgrade> to
+perform the upgrade if necessary. See C<svtype>.
+
+ void SvUPGRADE(SV* sv, svtype type)
+
+=for hackers
+Found in file sv.h
+
+=item SvUTF8
+X<SvUTF8>
+
+Returns a U32 value indicating whether the SV contains UTF-8 encoded data.
+Call this after SvPV() in case any call to string overloading updates the
+internal flag.
+
+ U32 SvUTF8(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUTF8_off
+X<SvUTF8_off>
+
+Unsets the UTF-8 status of an SV.
+
+ void SvUTF8_off(SV *sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUTF8_on
+X<SvUTF8_on>
+
+Turn on the UTF-8 status of an SV (the data is not changed, just the flag).
+Do not use frivolously.
+
+ void SvUTF8_on(SV *sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUV
+X<SvUV>
+
+Coerces the given SV to an unsigned integer and returns it. See C<SvUVx>
+for a version which guarantees to evaluate sv only once.
+
+ UV SvUV(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUVX
+X<SvUVX>
+
+Returns the raw value in the SV's UV slot, without checks or conversions.
+Only use when you are sure SvIOK is true. See also C<SvUV()>.
+
+ UV SvUVX(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUVx
+X<SvUVx>
+
+Coerces the given SV to an unsigned integer and returns it. Guarantees to
+C<sv> only once. Only use this if C<sv> is an expression with side effects,
+otherwise use the more efficient C<SvUV>.
+
+ UV SvUVx(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUV_nomg
+X<SvUV_nomg>
+
+Like C<SvUV> but doesn't process magic.
+
+ UV SvUV_nomg(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item SvUV_set
+X<SvUV_set>
+
+Set the value of the UV pointer in sv to val. See C<SvIV_set>.
+
+ void SvUV_set(SV* sv, UV val)
+
+=for hackers
+Found in file sv.h
+
+=item SvVOK
+X<SvVOK>
+
+Returns a boolean indicating whether the SV contains a v-string.
+
+ bool SvVOK(SV* sv)
+
+=for hackers
+Found in file sv.h
+
+=item sv_catpvn_nomg
+X<sv_catpvn_nomg>
+
+Like C<sv_catpvn> but doesn't process magic.
+
+ void sv_catpvn_nomg(SV* sv, const char* ptr, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
+=item sv_catsv_nomg
+X<sv_catsv_nomg>
+
+Like C<sv_catsv> but doesn't process magic.
+
+ void sv_catsv_nomg(SV* dsv, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item sv_derived_from
+X<sv_derived_from>
+
+Returns a boolean indicating whether the SV is derived from the specified class
+I<at the C level>. To check derivation at the Perl level, call C<isa()> as a
+normal Perl method.
+
+ bool sv_derived_from(SV* sv, const char *const name)
+
+=for hackers
+Found in file universal.c
+
+=item sv_does
+X<sv_does>
+
+Returns a boolean indicating whether the SV performs a specific, named role.
+The SV can be a Perl object or the name of a Perl class.
+
+ bool sv_does(SV* sv, const char *const name)
+
+=for hackers
+Found in file universal.c
+
+=item sv_report_used
+X<sv_report_used>
+
+Dump the contents of all SVs not yet freed. (Debugging aid).
+
+ void sv_report_used()
+
+=for hackers
+Found in file sv.c
+
+=item sv_setsv_nomg
+X<sv_setsv_nomg>
+
+Like C<sv_setsv> but doesn't process magic.
+
+ void sv_setsv_nomg(SV* dsv, SV* ssv)
+
+=for hackers
+Found in file sv.h
+
+=item sv_utf8_upgrade_nomg
+X<sv_utf8_upgrade_nomg>
+
+Like sv_utf8_upgrade, but doesn't do magic on C<sv>
+
+ STRLEN sv_utf8_upgrade_nomg(NN SV *sv)
+
+=for hackers
+Found in file sv.h
+
+
+=back
+
+=head1 SV-Body Allocation
+
+=over 8
+
+=item looks_like_number
+X<looks_like_number>
+
+Test if the content of an SV looks like a number (or is a number).
+C<Inf> and C<Infinity> are treated as numbers (so will not issue a
+non-numeric warning), even if your atof() doesn't grok them.
+
+ I32 looks_like_number(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item newRV_noinc
+X<newRV_noinc>
+
+Creates an RV wrapper for an SV. The reference count for the original
+SV is B<not> incremented.
+
+ SV* newRV_noinc(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item newSV
+X<newSV>
+
+Creates a new SV. A non-zero C<len> parameter indicates the number of
+bytes of preallocated string space the SV should have. An extra byte for a
+trailing NUL is also reserved. (SvPOK is not set for the SV even if string
+space is allocated.) The reference count for the new SV is set to 1.
+
+In 5.9.3, newSV() replaces the older NEWSV() API, and drops the first
+parameter, I<x>, a debug aid which allowed callers to identify themselves.
+This aid has been superseded by a new build option, PERL_MEM_LOG (see
+L<perlhack/PERL_MEM_LOG>). The older API is still there for use in XS
+modules supporting older perls.
+
+ SV* newSV(const STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item newSVhek
+X<newSVhek>
+
+Creates a new SV from the hash key structure. It will generate scalars that
+point to the shared string table where possible. Returns a new (undefined)
+SV if the hek is NULL.
+
+ SV* newSVhek(const HEK *const hek)
+
+=for hackers
+Found in file sv.c
+
+=item newSViv
+X<newSViv>
+
+Creates a new SV and copies an integer into it. The reference count for the
+SV is set to 1.
+
+ SV* newSViv(const IV i)
+
+=for hackers
+Found in file sv.c
+
+=item newSVnv
+X<newSVnv>
+
+Creates a new SV and copies a floating point value into it.
+The reference count for the SV is set to 1.
+
+ SV* newSVnv(const NV n)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpv
+X<newSVpv>
+
+Creates a new SV and copies a string into it. The reference count for the
+SV is set to 1. If C<len> is zero, Perl will compute the length using
+strlen(). For efficiency, consider using C<newSVpvn> instead.
+
+ SV* newSVpv(const char *const s, const STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpvf
+X<newSVpvf>
+
+Creates a new SV and initializes it with the string formatted like
+C<sprintf>.
+
+ SV* newSVpvf(const char *const pat, ...)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpvn
+X<newSVpvn>
+
+Creates a new SV and copies a string into it. The reference count for the
+SV is set to 1. Note that if C<len> is zero, Perl will create a zero length
+string. You are responsible for ensuring that the source string is at least
+C<len> bytes long. If the C<s> argument is NULL the new SV will be undefined.
+
+ SV* newSVpvn(const char *const s, const STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpvn_flags
+X<newSVpvn_flags>
+
+Creates a new SV and copies a string into it. The reference count for the
+SV is set to 1. Note that if C<len> is zero, Perl will create a zero length
+string. You are responsible for ensuring that the source string is at least
+C<len> bytes long. If the C<s> argument is NULL the new SV will be undefined.
+Currently the only flag bits accepted are C<SVf_UTF8> and C<SVs_TEMP>.
+If C<SVs_TEMP> is set, then C<sv2mortal()> is called on the result before
+returning. If C<SVf_UTF8> is set, C<s> is considered to be in UTF-8 and the
+C<SVf_UTF8> flag will be set on the new SV.
+C<newSVpvn_utf8()> is a convenience wrapper for this function, defined as
+
+ #define newSVpvn_utf8(s, len, u) \
+ newSVpvn_flags((s), (len), (u) ? SVf_UTF8 : 0)
+
+ SV* newSVpvn_flags(const char *const s, const STRLEN len, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpvn_share
+X<newSVpvn_share>
+
+Creates a new SV with its SvPVX_const pointing to a shared string in the string
+table. If the string does not already exist in the table, it is created
+first. Turns on READONLY and FAKE. If the C<hash> parameter is non-zero, that
+value is used; otherwise the hash is computed. The string's hash can be later
+be retrieved from the SV with the C<SvSHARED_HASH()> macro. The idea here is
+that as the string table is used for shared hash keys these strings will have
+SvPVX_const == HeKEY and hash lookup will avoid string compare.
+
+ SV* newSVpvn_share(const char* s, I32 len, U32 hash)
+
+=for hackers
+Found in file sv.c
+
+=item newSVpvs
+X<newSVpvs>
+
+Like C<newSVpvn>, but takes a literal string instead of a string/length pair.
+
+ SV* newSVpvs(const char* s)
+
+=for hackers
+Found in file handy.h
+
+=item newSVpvs_flags
+X<newSVpvs_flags>
+
+Like C<newSVpvn_flags>, but takes a literal string instead of a string/length
+pair.
+
+ SV* newSVpvs_flags(const char* s, U32 flags)
+
+=for hackers
+Found in file handy.h
+
+=item newSVpvs_share
+X<newSVpvs_share>
+
+Like C<newSVpvn_share>, but takes a literal string instead of a string/length
+pair and omits the hash parameter.
+
+ SV* newSVpvs_share(const char* s)
+
+=for hackers
+Found in file handy.h
+
+=item newSVrv
+X<newSVrv>
+
+Creates a new SV for the RV, C<rv>, to point to. If C<rv> is not an RV then
+it will be upgraded to one. If C<classname> is non-null then the new SV will
+be blessed in the specified package. The new SV is returned and its
+reference count is 1.
+
+ SV* newSVrv(SV *const rv, const char *const classname)
+
+=for hackers
+Found in file sv.c
+
+=item newSVsv
+X<newSVsv>
+
+Creates a new SV which is an exact duplicate of the original SV.
+(Uses C<sv_setsv>).
+
+ SV* newSVsv(SV *const old)
+
+=for hackers
+Found in file sv.c
+
+=item newSVuv
+X<newSVuv>
+
+Creates a new SV and copies an unsigned integer into it.
+The reference count for the SV is set to 1.
+
+ SV* newSVuv(const UV u)
+
+=for hackers
+Found in file sv.c
+
+=item newSV_type
+X<newSV_type>
+
+Creates a new SV, of the type specified. The reference count for the new SV
+is set to 1.
+
+ SV* newSV_type(const svtype type)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2bool
+X<sv_2bool>
+
+This function is only called on magical items, and is only used by
+sv_true() or its macro equivalent.
+
+ bool sv_2bool(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2cv
+X<sv_2cv>
+
+Using various gambits, try to get a CV from an SV; in addition, try if
+possible to set C<*st> and C<*gvp> to the stash and GV associated with it.
+The flags in C<lref> are passed to gv_fetchsv.
+
+ CV* sv_2cv(SV* sv, HV **const st, GV **const gvp, const I32 lref)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2io
+X<sv_2io>
+
+Using various gambits, try to get an IO from an SV: the IO slot if its a
+GV; or the recursive result if we're an RV; or the IO slot of the symbol
+named after the PV if we're a string.
+
+ IO* sv_2io(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2iv_flags
+X<sv_2iv_flags>
+
+Return the integer value of an SV, doing any necessary string
+conversion. If flags includes SV_GMAGIC, does an mg_get() first.
+Normally used via the C<SvIV(sv)> and C<SvIVx(sv)> macros.
+
+ IV sv_2iv_flags(SV *const sv, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2mortal
+X<sv_2mortal>
+
+Marks an existing SV as mortal. The SV will be destroyed "soon", either
+by an explicit call to FREETMPS, or by an implicit call at places such as
+statement boundaries. SvTEMP() is turned on which means that the SV's
+string buffer can be "stolen" if this SV is copied. See also C<sv_newmortal>
+and C<sv_mortalcopy>.
+
+ SV* sv_2mortal(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2nv
+X<sv_2nv>
+
+Return the num value of an SV, doing any necessary string or integer
+conversion, magic etc. Normally used via the C<SvNV(sv)> and C<SvNVx(sv)>
+macros.
+
+ NV sv_2nv(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2pvbyte
+X<sv_2pvbyte>
+
+Return a pointer to the byte-encoded representation of the SV, and set *lp
+to its length. May cause the SV to be downgraded from UTF-8 as a
+side-effect.
+
+Usually accessed via the C<SvPVbyte> macro.
+
+ char* sv_2pvbyte(SV *const sv, STRLEN *const lp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2pvutf8
+X<sv_2pvutf8>
+
+Return a pointer to the UTF-8-encoded representation of the SV, and set *lp
+to its length. May cause the SV to be upgraded to UTF-8 as a side-effect.
+
+Usually accessed via the C<SvPVutf8> macro.
+
+ char* sv_2pvutf8(SV *const sv, STRLEN *const lp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2pv_flags
+X<sv_2pv_flags>
+
+Returns a pointer to the string value of an SV, and sets *lp to its length.
+If flags includes SV_GMAGIC, does an mg_get() first. Coerces sv to a string
+if necessary.
+Normally invoked via the C<SvPV_flags> macro. C<sv_2pv()> and C<sv_2pv_nomg>
+usually end up here too.
+
+ char* sv_2pv_flags(SV *const sv, STRLEN *const lp, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_2uv_flags
+X<sv_2uv_flags>
+
+Return the unsigned integer value of an SV, doing any necessary string
+conversion. If flags includes SV_GMAGIC, does an mg_get() first.
+Normally used via the C<SvUV(sv)> and C<SvUVx(sv)> macros.
+
+ UV sv_2uv_flags(SV *const sv, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_backoff
+X<sv_backoff>
+
+Remove any string offset. You should normally use the C<SvOOK_off> macro
+wrapper instead.
+
+ int sv_backoff(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_bless
+X<sv_bless>
+
+Blesses an SV into a specified package. The SV must be an RV. The package
+must be designated by its stash (see C<gv_stashpv()>). The reference count
+of the SV is unaffected.
+
+ SV* sv_bless(SV *const sv, HV *const stash)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpv
+X<sv_catpv>
+
+Concatenates the string onto the end of the string which is in the SV.
+If the SV has the UTF-8 status set, then the bytes appended should be
+valid UTF-8. Handles 'get' magic, but not 'set' magic. See C<sv_catpv_mg>.
+
+ void sv_catpv(SV *const sv, const char* ptr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpvf
+X<sv_catpvf>
+
+Processes its arguments like C<sprintf> and appends the formatted
+output to an SV. If the appended data contains "wide" characters
+(including, but not limited to, SVs with a UTF-8 PV formatted with %s,
+and characters >255 formatted with %c), the original SV might get
+upgraded to UTF-8. Handles 'get' magic, but not 'set' magic. See
+C<sv_catpvf_mg>. If the original SV was UTF-8, the pattern should be
+valid UTF-8; if the original SV was bytes, the pattern should be too.
+
+ void sv_catpvf(SV *const sv, const char *const pat, ...)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpvf_mg
+X<sv_catpvf_mg>
+
+Like C<sv_catpvf>, but also handles 'set' magic.
+
+ void sv_catpvf_mg(SV *const sv, const char *const pat, ...)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpvn
+X<sv_catpvn>
+
+Concatenates the string onto the end of the string which is in the SV. The
+C<len> indicates number of bytes to copy. If the SV has the UTF-8
+status set, then the bytes appended should be valid UTF-8.
+Handles 'get' magic, but not 'set' magic. See C<sv_catpvn_mg>.
+
+ void sv_catpvn(SV *dsv, const char *sstr, STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpvn_flags
+X<sv_catpvn_flags>
+
+Concatenates the string onto the end of the string which is in the SV. The
+C<len> indicates number of bytes to copy. If the SV has the UTF-8
+status set, then the bytes appended should be valid UTF-8.
+If C<flags> has C<SV_GMAGIC> bit set, will C<mg_get> on C<dsv> if
+appropriate, else not. C<sv_catpvn> and C<sv_catpvn_nomg> are implemented
+in terms of this function.
+
+ void sv_catpvn_flags(SV *const dstr, const char *sstr, const STRLEN len, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catpvs
+X<sv_catpvs>
+
+Like C<sv_catpvn>, but takes a literal string instead of a string/length pair.
+
+ void sv_catpvs(SV* sv, const char* s)
+
+=for hackers
+Found in file handy.h
+
+=item sv_catpv_mg
+X<sv_catpv_mg>
+
+Like C<sv_catpv>, but also handles 'set' magic.
+
+ void sv_catpv_mg(SV *const sv, const char *const ptr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catsv
+X<sv_catsv>
+
+Concatenates the string from SV C<ssv> onto the end of the string in
+SV C<dsv>. Modifies C<dsv> but not C<ssv>. Handles 'get' magic, but
+not 'set' magic. See C<sv_catsv_mg>.
+
+ void sv_catsv(SV *dstr, SV *sstr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_catsv_flags
+X<sv_catsv_flags>
+
+Concatenates the string from SV C<ssv> onto the end of the string in
+SV C<dsv>. Modifies C<dsv> but not C<ssv>. If C<flags> has C<SV_GMAGIC>
+bit set, will C<mg_get> on the SVs if appropriate, else not. C<sv_catsv>
+and C<sv_catsv_nomg> are implemented in terms of this function.
+
+ void sv_catsv_flags(SV *const dsv, SV *const ssv, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_chop
+X<sv_chop>
+
+Efficient removal of characters from the beginning of the string buffer.
+SvPOK(sv) must be true and the C<ptr> must be a pointer to somewhere inside
+the string buffer. The C<ptr> becomes the first character of the adjusted
+string. Uses the "OOK hack".
+Beware: after this function returns, C<ptr> and SvPVX_const(sv) may no longer
+refer to the same chunk of data.
+
+ void sv_chop(SV *const sv, const char *const ptr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_clear
+X<sv_clear>
+
+Clear an SV: call any destructors, free up any memory used by the body,
+and free the body itself. The SV's head is I<not> freed, although
+its type is set to all 1's so that it won't inadvertently be assumed
+to be live during global destruction etc.
+This function should only be called when REFCNT is zero. Most of the time
+you'll want to call C<sv_free()> (or its macro wrapper C<SvREFCNT_dec>)
+instead.
+
+ void sv_clear(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_cmp
+X<sv_cmp>
+
+Compares the strings in two SVs. Returns -1, 0, or 1 indicating whether the
+string in C<sv1> is less than, equal to, or greater than the string in
+C<sv2>. Is UTF-8 and 'use bytes' aware, handles get magic, and will
+coerce its args to strings if necessary. See also C<sv_cmp_locale>.
+
+ I32 sv_cmp(SV *const sv1, SV *const sv2)
+
+=for hackers
+Found in file sv.c
+
+=item sv_cmp_locale
+X<sv_cmp_locale>
+
+Compares the strings in two SVs in a locale-aware manner. Is UTF-8 and
+'use bytes' aware, handles get magic, and will coerce its args to strings
+if necessary. See also C<sv_cmp>.
+
+ I32 sv_cmp_locale(SV *const sv1, SV *const sv2)
+
+=for hackers
+Found in file sv.c
+
+=item sv_collxfrm
+X<sv_collxfrm>
+
+Add Collate Transform magic to an SV if it doesn't already have it.
+
+Any scalar variable may carry PERL_MAGIC_collxfrm magic that contains the
+scalar data of the variable, but transformed to such a format that a normal
+memory comparison can be used to compare the data according to the locale
+settings.
+
+ char* sv_collxfrm(SV *const sv, STRLEN *const nxp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_copypv
+X<sv_copypv>
+
+Copies a stringified representation of the source SV into the
+destination SV. Automatically performs any necessary mg_get and
+coercion of numeric values into strings. Guaranteed to preserve
+UTF8 flag even from overloaded objects. Similar in nature to
+sv_2pv[_flags] but operates directly on an SV instead of just the
+string. Mostly uses sv_2pv_flags to do its work, except when that
+would lose the UTF-8'ness of the PV.
+
+ void sv_copypv(SV *const dsv, SV *const ssv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_dec
+X<sv_dec>
+
+Auto-decrement of the value in the SV, doing string to numeric conversion
+if necessary. Handles 'get' magic.
+
+ void sv_dec(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_eq
+X<sv_eq>
+
+Returns a boolean indicating whether the strings in the two SVs are
+identical. Is UTF-8 and 'use bytes' aware, handles get magic, and will
+coerce its args to strings if necessary.
+
+ I32 sv_eq(SV* sv1, SV* sv2)
+
+=for hackers
+Found in file sv.c
+
+=item sv_force_normal_flags
+X<sv_force_normal_flags>
+
+Undo various types of fakery on an SV: if the PV is a shared string, make
+a private copy; if we're a ref, stop refing; if we're a glob, downgrade to
+an xpvmg; if we're a copy-on-write scalar, this is the on-write time when
+we do the copy, and is also used locally. If C<SV_COW_DROP_PV> is set
+then a copy-on-write scalar drops its PV buffer (if any) and becomes
+SvPOK_off rather than making a copy. (Used where this scalar is about to be
+set to some other value.) In addition, the C<flags> parameter gets passed to
+C<sv_unref_flags()> when unrefing. C<sv_force_normal> calls this function
+with flags set to 0.
+
+ void sv_force_normal_flags(SV *const sv, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_free
+X<sv_free>
+
+Decrement an SV's reference count, and if it drops to zero, call
+C<sv_clear> to invoke destructors and free up any memory used by
+the body; finally, deallocate the SV's head itself.
+Normally called via a wrapper macro C<SvREFCNT_dec>.
+
+ void sv_free(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_gets
+X<sv_gets>
+
+Get a line from the filehandle and store it into the SV, optionally
+appending to the currently-stored string.
+
+ char* sv_gets(SV *const sv, PerlIO *const fp, I32 append)
+
+=for hackers
+Found in file sv.c
+
+=item sv_grow
+X<sv_grow>
+
+Expands the character buffer in the SV. If necessary, uses C<sv_unref> and
+upgrades the SV to C<SVt_PV>. Returns a pointer to the character buffer.
+Use the C<SvGROW> wrapper instead.
+
+ char* sv_grow(SV *const sv, STRLEN newlen)
+
+=for hackers
+Found in file sv.c
+
+=item sv_inc
+X<sv_inc>
+
+Auto-increment of the value in the SV, doing string to numeric conversion
+if necessary. Handles 'get' magic.
+
+ void sv_inc(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_insert
+X<sv_insert>
+
+Inserts a string at the specified offset/length within the SV. Similar to
+the Perl substr() function. Handles get magic.
+
+ void sv_insert(SV *const bigstr, const STRLEN offset, const STRLEN len, const char *const little, const STRLEN littlelen)
+
+=for hackers
+Found in file sv.c
+
+=item sv_insert_flags
+X<sv_insert_flags>
+
+Same as C<sv_insert>, but the extra C<flags> are passed the C<SvPV_force_flags> that applies to C<bigstr>.
+
+ void sv_insert_flags(SV *const bigstr, const STRLEN offset, const STRLEN len, const char *const little, const STRLEN littlelen, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_isa
+X<sv_isa>
+
+Returns a boolean indicating whether the SV is blessed into the specified
+class. This does not check for subtypes; use C<sv_derived_from> to verify
+an inheritance relationship.
+
+ int sv_isa(SV* sv, const char *const name)
+
+=for hackers
+Found in file sv.c
+
+=item sv_isobject
+X<sv_isobject>
+
+Returns a boolean indicating whether the SV is an RV pointing to a blessed
+object. If the SV is not an RV, or if the object is not blessed, then this
+will return false.
+
+ int sv_isobject(SV* sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_len
+X<sv_len>
+
+Returns the length of the string in the SV. Handles magic and type
+coercion. See also C<SvCUR>, which gives raw access to the xpv_cur slot.
+
+ STRLEN sv_len(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_len_utf8
+X<sv_len_utf8>
+
+Returns the number of characters in the string in an SV, counting wide
+UTF-8 bytes as a single character. Handles magic and type coercion.
+
+ STRLEN sv_len_utf8(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_magic
+X<sv_magic>
+
+Adds magic to an SV. First upgrades C<sv> to type C<SVt_PVMG> if necessary,
+then adds a new magic item of type C<how> to the head of the magic list.
+
+See C<sv_magicext> (which C<sv_magic> now calls) for a description of the
+handling of the C<name> and C<namlen> arguments.
+
+You need to use C<sv_magicext> to add magic to SvREADONLY SVs and also
+to add more than one instance of the same 'how'.
+
+ void sv_magic(SV *const sv, SV *const obj, const int how, const char *const name, const I32 namlen)
+
+=for hackers
+Found in file sv.c
+
+=item sv_magicext
+X<sv_magicext>
+
+Adds magic to an SV, upgrading it if necessary. Applies the
+supplied vtable and returns a pointer to the magic added.
+
+Note that C<sv_magicext> will allow things that C<sv_magic> will not.
+In particular, you can add magic to SvREADONLY SVs, and add more than
+one instance of the same 'how'.
+
+If C<namlen> is greater than zero then a C<savepvn> I<copy> of C<name> is
+stored, if C<namlen> is zero then C<name> is stored as-is and - as another
+special case - if C<(name && namlen == HEf_SVKEY)> then C<name> is assumed
+to contain an C<SV*> and is stored as-is with its REFCNT incremented.
+
+(This is now used as a subroutine by C<sv_magic>.)
+
+ MAGIC * sv_magicext(SV *const sv, SV *const obj, const int how, const MGVTBL *const vtbl, const char *const name, const I32 namlen)
+
+=for hackers
+Found in file sv.c
+
+=item sv_mortalcopy
+X<sv_mortalcopy>
+
+Creates a new SV which is a copy of the original SV (using C<sv_setsv>).
+The new SV is marked as mortal. It will be destroyed "soon", either by an
+explicit call to FREETMPS, or by an implicit call at places such as
+statement boundaries. See also C<sv_newmortal> and C<sv_2mortal>.
+
+ SV* sv_mortalcopy(SV *const oldsv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_newmortal
+X<sv_newmortal>
+
+Creates a new null SV which is mortal. The reference count of the SV is
+set to 1. It will be destroyed "soon", either by an explicit call to
+FREETMPS, or by an implicit call at places such as statement boundaries.
+See also C<sv_mortalcopy> and C<sv_2mortal>.
+
+ SV* sv_newmortal()
+
+=for hackers
+Found in file sv.c
+
+=item sv_newref
+X<sv_newref>
+
+Increment an SV's reference count. Use the C<SvREFCNT_inc()> wrapper
+instead.
+
+ SV* sv_newref(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pos_b2u
+X<sv_pos_b2u>
+
+Converts the value pointed to by offsetp from a count of bytes from the
+start of the string, to a count of the equivalent number of UTF-8 chars.
+Handles magic and type coercion.
+
+ void sv_pos_b2u(SV *const sv, I32 *const offsetp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pos_u2b
+X<sv_pos_u2b>
+
+Converts the value pointed to by offsetp from a count of UTF-8 chars from
+the start of the string, to a count of the equivalent number of bytes; if
+lenp is non-zero, it does the same to lenp, but this time starting from
+the offset, rather than from the start of the string. Handles magic and
+type coercion.
+
+Use C<sv_pos_u2b_flags> in preference, which correctly handles strings longer
+than 2Gb.
+
+ void sv_pos_u2b(SV *const sv, I32 *const offsetp, I32 *const lenp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pos_u2b_flags
+X<sv_pos_u2b_flags>
+
+Converts the value pointed to by offsetp from a count of UTF-8 chars from
+the start of the string, to a count of the equivalent number of bytes; if
+lenp is non-zero, it does the same to lenp, but this time starting from
+the offset, rather than from the start of the string. Handles type coercion.
+I<flags> is passed to C<SvPV_flags>, and usually should be
+C<SV_GMAGIC|SV_CONST_RETURN> to handle magic.
+
+ STRLEN sv_pos_u2b_flags(SV *const sv, STRLEN uoffset, STRLEN *const lenp, U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pvbyten_force
+X<sv_pvbyten_force>
+
+The backend for the C<SvPVbytex_force> macro. Always use the macro instead.
+
+ char* sv_pvbyten_force(SV *const sv, STRLEN *const lp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pvn_force
+X<sv_pvn_force>
+
+Get a sensible string out of the SV somehow.
+A private implementation of the C<SvPV_force> macro for compilers which
+can't cope with complex macro expressions. Always use the macro instead.
+
+ char* sv_pvn_force(SV* sv, STRLEN* lp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pvn_force_flags
+X<sv_pvn_force_flags>
+
+Get a sensible string out of the SV somehow.
+If C<flags> has C<SV_GMAGIC> bit set, will C<mg_get> on C<sv> if
+appropriate, else not. C<sv_pvn_force> and C<sv_pvn_force_nomg> are
+implemented in terms of this function.
+You normally want to use the various wrapper macros instead: see
+C<SvPV_force> and C<SvPV_force_nomg>
+
+ char* sv_pvn_force_flags(SV *const sv, STRLEN *const lp, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_pvutf8n_force
+X<sv_pvutf8n_force>
+
+The backend for the C<SvPVutf8x_force> macro. Always use the macro instead.
+
+ char* sv_pvutf8n_force(SV *const sv, STRLEN *const lp)
+
+=for hackers
+Found in file sv.c
+
+=item sv_reftype
+X<sv_reftype>
+
+Returns a string describing what the SV is a reference to.
+
+ const char* sv_reftype(const SV *const sv, const int ob)
+
+=for hackers
+Found in file sv.c
+
+=item sv_replace
+X<sv_replace>
+
+Make the first argument a copy of the second, then delete the original.
+The target SV physically takes over ownership of the body of the source SV
+and inherits its flags; however, the target keeps any magic it owns,
+and any magic in the source is discarded.
+Note that this is a rather specialist SV copying operation; most of the
+time you'll want to use C<sv_setsv> or one of its many macro front-ends.
+
+ void sv_replace(SV *const sv, SV *const nsv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_reset
+X<sv_reset>
+
+Underlying implementation for the C<reset> Perl function.
+Note that the perl-level function is vaguely deprecated.
+
+ void sv_reset(const char* s, HV *const stash)
+
+=for hackers
+Found in file sv.c
+
+=item sv_rvweaken
+X<sv_rvweaken>
+
+Weaken a reference: set the C<SvWEAKREF> flag on this RV; give the
+referred-to SV C<PERL_MAGIC_backref> magic if it hasn't already; and
+push a back-reference to this RV onto the array of backreferences
+associated with that magic. If the RV is magical, set magic will be
+called after the RV is cleared.
+
+ SV* sv_rvweaken(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setiv
+X<sv_setiv>
+
+Copies an integer into the given SV, upgrading first if necessary.
+Does not handle 'set' magic. See also C<sv_setiv_mg>.
+
+ void sv_setiv(SV *const sv, const IV num)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setiv_mg
+X<sv_setiv_mg>
+
+Like C<sv_setiv>, but also handles 'set' magic.
+
+ void sv_setiv_mg(SV *const sv, const IV i)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setnv
+X<sv_setnv>
+
+Copies a double into the given SV, upgrading first if necessary.
+Does not handle 'set' magic. See also C<sv_setnv_mg>.
+
+ void sv_setnv(SV *const sv, const NV num)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setnv_mg
+X<sv_setnv_mg>
+
+Like C<sv_setnv>, but also handles 'set' magic.
+
+ void sv_setnv_mg(SV *const sv, const NV num)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpv
+X<sv_setpv>
+
+Copies a string into an SV. The string must be null-terminated. Does not
+handle 'set' magic. See C<sv_setpv_mg>.
+
+ void sv_setpv(SV *const sv, const char *const ptr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpvf
+X<sv_setpvf>
+
+Works like C<sv_catpvf> but copies the text into the SV instead of
+appending it. Does not handle 'set' magic. See C<sv_setpvf_mg>.
+
+ void sv_setpvf(SV *const sv, const char *const pat, ...)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpvf_mg
+X<sv_setpvf_mg>
+
+Like C<sv_setpvf>, but also handles 'set' magic.
+
+ void sv_setpvf_mg(SV *const sv, const char *const pat, ...)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpviv
+X<sv_setpviv>
+
+Copies an integer into the given SV, also updating its string value.
+Does not handle 'set' magic. See C<sv_setpviv_mg>.
+
+ void sv_setpviv(SV *const sv, const IV num)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpviv_mg
+X<sv_setpviv_mg>
+
+Like C<sv_setpviv>, but also handles 'set' magic.
+
+ void sv_setpviv_mg(SV *const sv, const IV iv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpvn
+X<sv_setpvn>
+
+Copies a string into an SV. The C<len> parameter indicates the number of
+bytes to be copied. If the C<ptr> argument is NULL the SV will become
+undefined. Does not handle 'set' magic. See C<sv_setpvn_mg>.
+
+ void sv_setpvn(SV *const sv, const char *const ptr, const STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpvn_mg
+X<sv_setpvn_mg>
+
+Like C<sv_setpvn>, but also handles 'set' magic.
+
+ void sv_setpvn_mg(SV *const sv, const char *const ptr, const STRLEN len)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setpvs
+X<sv_setpvs>
+
+Like C<sv_setpvn>, but takes a literal string instead of a string/length pair.
+
+ void sv_setpvs(SV* sv, const char* s)
+
+=for hackers
+Found in file handy.h
+
+=item sv_setpv_mg
+X<sv_setpv_mg>
+
+Like C<sv_setpv>, but also handles 'set' magic.
+
+ void sv_setpv_mg(SV *const sv, const char *const ptr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setref_iv
+X<sv_setref_iv>
+
+Copies an integer into a new SV, optionally blessing the SV. The C<rv>
+argument will be upgraded to an RV. That RV will be modified to point to
+the new SV. The C<classname> argument indicates the package for the
+blessing. Set C<classname> to C<NULL> to avoid the blessing. The new SV
+will have a reference count of 1, and the RV will be returned.
+
+ SV* sv_setref_iv(SV *const rv, const char *const classname, const IV iv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setref_nv
+X<sv_setref_nv>
+
+Copies a double into a new SV, optionally blessing the SV. The C<rv>
+argument will be upgraded to an RV. That RV will be modified to point to
+the new SV. The C<classname> argument indicates the package for the
+blessing. Set C<classname> to C<NULL> to avoid the blessing. The new SV
+will have a reference count of 1, and the RV will be returned.
+
+ SV* sv_setref_nv(SV *const rv, const char *const classname, const NV nv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setref_pv
+X<sv_setref_pv>
+
+Copies a pointer into a new SV, optionally blessing the SV. The C<rv>
+argument will be upgraded to an RV. That RV will be modified to point to
+the new SV. If the C<pv> argument is NULL then C<PL_sv_undef> will be placed
+into the SV. The C<classname> argument indicates the package for the
+blessing. Set C<classname> to C<NULL> to avoid the blessing. The new SV
+will have a reference count of 1, and the RV will be returned.
+
+Do not use with other Perl types such as HV, AV, SV, CV, because those
+objects will become corrupted by the pointer copy process.
+
+Note that C<sv_setref_pvn> copies the string while this copies the pointer.
+
+ SV* sv_setref_pv(SV *const rv, const char *const classname, void *const pv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setref_pvn
+X<sv_setref_pvn>
+
+Copies a string into a new SV, optionally blessing the SV. The length of the
+string must be specified with C<n>. The C<rv> argument will be upgraded to
+an RV. That RV will be modified to point to the new SV. The C<classname>
+argument indicates the package for the blessing. Set C<classname> to
+C<NULL> to avoid the blessing. The new SV will have a reference count
+of 1, and the RV will be returned.
+
+Note that C<sv_setref_pv> copies the pointer while this copies the string.
+
+ SV* sv_setref_pvn(SV *const rv, const char *const classname, const char *const pv, const STRLEN n)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setref_uv
+X<sv_setref_uv>
+
+Copies an unsigned integer into a new SV, optionally blessing the SV. The C<rv>
+argument will be upgraded to an RV. That RV will be modified to point to
+the new SV. The C<classname> argument indicates the package for the
+blessing. Set C<classname> to C<NULL> to avoid the blessing. The new SV
+will have a reference count of 1, and the RV will be returned.
+
+ SV* sv_setref_uv(SV *const rv, const char *const classname, const UV uv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setsv
+X<sv_setsv>
+
+Copies the contents of the source SV C<ssv> into the destination SV
+C<dsv>. The source SV may be destroyed if it is mortal, so don't use this
+function if the source SV needs to be reused. Does not handle 'set' magic.
+Loosely speaking, it performs a copy-by-value, obliterating any previous
+content of the destination.
+
+You probably want to use one of the assortment of wrappers, such as
+C<SvSetSV>, C<SvSetSV_nosteal>, C<SvSetMagicSV> and
+C<SvSetMagicSV_nosteal>.
+
+ void sv_setsv(SV *dstr, SV *sstr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setsv_flags
+X<sv_setsv_flags>
+
+Copies the contents of the source SV C<ssv> into the destination SV
+C<dsv>. The source SV may be destroyed if it is mortal, so don't use this
+function if the source SV needs to be reused. Does not handle 'set' magic.
+Loosely speaking, it performs a copy-by-value, obliterating any previous
+content of the destination.
+If the C<flags> parameter has the C<SV_GMAGIC> bit set, will C<mg_get> on
+C<ssv> if appropriate, else not. If the C<flags> parameter has the
+C<NOSTEAL> bit set then the buffers of temps will not be stolen. <sv_setsv>
+and C<sv_setsv_nomg> are implemented in terms of this function.
+
+You probably want to use one of the assortment of wrappers, such as
+C<SvSetSV>, C<SvSetSV_nosteal>, C<SvSetMagicSV> and
+C<SvSetMagicSV_nosteal>.
+
+This is the primary function for copying scalars, and most other
+copy-ish functions and macros use this underneath.
+
+ void sv_setsv_flags(SV *dstr, SV *sstr, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setsv_mg
+X<sv_setsv_mg>
+
+Like C<sv_setsv>, but also handles 'set' magic.
+
+ void sv_setsv_mg(SV *const dstr, SV *const sstr)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setuv
+X<sv_setuv>
+
+Copies an unsigned integer into the given SV, upgrading first if necessary.
+Does not handle 'set' magic. See also C<sv_setuv_mg>.
+
+ void sv_setuv(SV *const sv, const UV num)
+
+=for hackers
+Found in file sv.c
+
+=item sv_setuv_mg
+X<sv_setuv_mg>
+
+Like C<sv_setuv>, but also handles 'set' magic.
+
+ void sv_setuv_mg(SV *const sv, const UV u)
+
+=for hackers
+Found in file sv.c
+
+=item sv_tainted
+X<sv_tainted>
+
+Test an SV for taintedness. Use C<SvTAINTED> instead.
+ bool sv_tainted(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_true
+X<sv_true>
+
+Returns true if the SV has a true value by Perl's rules.
+Use the C<SvTRUE> macro instead, which may call C<sv_true()> or may
+instead use an in-line version.
+
+ I32 sv_true(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_unmagic
+X<sv_unmagic>
+
+Removes all magic of type C<type> from an SV.
+
+ int sv_unmagic(SV *const sv, const int type)
+
+=for hackers
+Found in file sv.c
+
+=item sv_unref_flags
+X<sv_unref_flags>
+
+Unsets the RV status of the SV, and decrements the reference count of
+whatever was being referenced by the RV. This can almost be thought of
+as a reversal of C<newSVrv>. The C<cflags> argument can contain
+C<SV_IMMEDIATE_UNREF> to force the reference count to be decremented
+(otherwise the decrementing is conditional on the reference count being
+different from one or the reference being a readonly SV).
+See C<SvROK_off>.
+
+ void sv_unref_flags(SV *const ref, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_untaint
+X<sv_untaint>
+
+Untaint an SV. Use C<SvTAINTED_off> instead.
+ void sv_untaint(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_upgrade
+X<sv_upgrade>
+
+Upgrade an SV to a more complex form. Generally adds a new body type to the
+SV, then copies across as much information as possible from the old body.
+You generally want to use the C<SvUPGRADE> macro wrapper. See also C<svtype>.
+
+ void sv_upgrade(SV *const sv, svtype new_type)
+
+=for hackers
+Found in file sv.c
+
+=item sv_usepvn_flags
+X<sv_usepvn_flags>
+
+Tells an SV to use C<ptr> to find its string value. Normally the
+string is stored inside the SV but sv_usepvn allows the SV to use an
+outside string. The C<ptr> should point to memory that was allocated
+by C<malloc>. The string length, C<len>, must be supplied. By default
+this function will realloc (i.e. move) the memory pointed to by C<ptr>,
+so that pointer should not be freed or used by the programmer after
+giving it to sv_usepvn, and neither should any pointers from "behind"
+that pointer (e.g. ptr + 1) be used.
+
+If C<flags> & SV_SMAGIC is true, will call SvSETMAGIC. If C<flags> &
+SV_HAS_TRAILING_NUL is true, then C<ptr[len]> must be NUL, and the realloc
+will be skipped. (i.e. the buffer is actually at least 1 byte longer than
+C<len>, and already meets the requirements for storing in C<SvPVX>)
+
+ void sv_usepvn_flags(SV *const sv, char* ptr, const STRLEN len, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_decode
+X<sv_utf8_decode>
+
+If the PV of the SV is an octet sequence in UTF-8
+and contains a multiple-byte character, the C<SvUTF8> flag is turned on
+so that it looks like a character. If the PV contains only single-byte
+characters, the C<SvUTF8> flag stays being off.
+Scans PV for validity and returns false if the PV is invalid UTF-8.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ bool sv_utf8_decode(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_downgrade
+X<sv_utf8_downgrade>
+
+Attempts to convert the PV of an SV from characters to bytes.
+If the PV contains a character that cannot fit
+in a byte, this conversion will fail;
+in this case, either returns false or, if C<fail_ok> is not
+true, croaks.
+
+This is not as a general purpose Unicode to byte encoding interface:
+use the Encode extension for that.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ bool sv_utf8_downgrade(SV *const sv, const bool fail_ok)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_encode
+X<sv_utf8_encode>
+
+Converts the PV of an SV to UTF-8, but then turns the C<SvUTF8>
+flag off so that it looks like octets again.
+
+ void sv_utf8_encode(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_upgrade
+X<sv_utf8_upgrade>
+
+Converts the PV of an SV to its UTF-8-encoded form.
+Forces the SV to string form if it is not already.
+Will C<mg_get> on C<sv> if appropriate.
+Always sets the SvUTF8 flag to avoid future validity checks even
+if the whole string is the same in UTF-8 as not.
+Returns the number of bytes in the converted string
+
+This is not as a general purpose byte encoding to Unicode interface:
+use the Encode extension for that.
+
+ STRLEN sv_utf8_upgrade(SV *sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_upgrade_flags
+X<sv_utf8_upgrade_flags>
+
+Converts the PV of an SV to its UTF-8-encoded form.
+Forces the SV to string form if it is not already.
+Always sets the SvUTF8 flag to avoid future validity checks even
+if all the bytes are invariant in UTF-8. If C<flags> has C<SV_GMAGIC> bit set,
+will C<mg_get> on C<sv> if appropriate, else not.
+Returns the number of bytes in the converted string
+C<sv_utf8_upgrade> and
+C<sv_utf8_upgrade_nomg> are implemented in terms of this function.
+
+This is not as a general purpose byte encoding to Unicode interface:
+use the Encode extension for that.
+
+ STRLEN sv_utf8_upgrade_flags(SV *const sv, const I32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_utf8_upgrade_nomg
+X<sv_utf8_upgrade_nomg>
+
+Like sv_utf8_upgrade, but doesn't do magic on C<sv>
+
+ STRLEN sv_utf8_upgrade_nomg(SV *sv)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vcatpvf
+X<sv_vcatpvf>
+
+Processes its arguments like C<vsprintf> and appends the formatted output
+to an SV. Does not handle 'set' magic. See C<sv_vcatpvf_mg>.
+
+Usually used via its frontend C<sv_catpvf>.
+
+ void sv_vcatpvf(SV *const sv, const char *const pat, va_list *const args)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vcatpvfn
+X<sv_vcatpvfn>
+
+Processes its arguments like C<vsprintf> and appends the formatted output
+to an SV. Uses an array of SVs if the C style variable argument list is
+missing (NULL). When running with taint checks enabled, indicates via
+C<maybe_tainted> if results are untrustworthy (often due to the use of
+locales).
+
+Usually used via one of its frontends C<sv_vcatpvf> and C<sv_vcatpvf_mg>.
+
+ void sv_vcatpvfn(SV *const sv, const char *const pat, const STRLEN patlen, va_list *const args, SV **const svargs, const I32 svmax, bool *const maybe_tainted)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vcatpvf_mg
+X<sv_vcatpvf_mg>
+
+Like C<sv_vcatpvf>, but also handles 'set' magic.
+
+Usually used via its frontend C<sv_catpvf_mg>.
+
+ void sv_vcatpvf_mg(SV *const sv, const char *const pat, va_list *const args)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vsetpvf
+X<sv_vsetpvf>
+
+Works like C<sv_vcatpvf> but copies the text into the SV instead of
+appending it. Does not handle 'set' magic. See C<sv_vsetpvf_mg>.
+
+Usually used via its frontend C<sv_setpvf>.
+
+ void sv_vsetpvf(SV *const sv, const char *const pat, va_list *const args)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vsetpvfn
+X<sv_vsetpvfn>
+
+Works like C<sv_vcatpvfn> but copies the text into the SV instead of
+appending it.
+
+Usually used via one of its frontends C<sv_vsetpvf> and C<sv_vsetpvf_mg>.
+
+ void sv_vsetpvfn(SV *const sv, const char *const pat, const STRLEN patlen, va_list *const args, SV **const svargs, const I32 svmax, bool *const maybe_tainted)
+
+=for hackers
+Found in file sv.c
+
+=item sv_vsetpvf_mg
+X<sv_vsetpvf_mg>
+
+Like C<sv_vsetpvf>, but also handles 'set' magic.
+
+Usually used via its frontend C<sv_setpvf_mg>.
+
+ void sv_vsetpvf_mg(SV *const sv, const char *const pat, va_list *const args)
+
+=for hackers
+Found in file sv.c
+
+
+=back
+
+=head1 Unicode Support
+
+=over 8
+
+=item bytes_from_utf8
+X<bytes_from_utf8>
+
+Converts a string C<s> of length C<len> from UTF-8 into native byte encoding.
+Unlike C<utf8_to_bytes> but like C<bytes_to_utf8>, returns a pointer to
+the newly-created string, and updates C<len> to contain the new
+length. Returns the original string if no conversion occurs, C<len>
+is unchanged. Do nothing if C<is_utf8> points to 0. Sets C<is_utf8> to
+0 if C<s> is converted or consisted entirely of characters that are invariant
+in utf8 (i.e., US-ASCII on non-EBCDIC machines).
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ U8* bytes_from_utf8(const U8 *s, STRLEN *len, bool *is_utf8)
+
+=for hackers
+Found in file utf8.c
+
+=item bytes_to_utf8
+X<bytes_to_utf8>
+
+Converts a string C<s> of length C<len> from the native encoding into UTF-8.
+Returns a pointer to the newly-created string, and sets C<len> to
+reflect the new length.
+
+A NUL character will be written after the end of the string.
+
+If you want to convert to UTF-8 from encodings other than
+the native (Latin1 or EBCDIC),
+see sv_recode_to_utf8().
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ U8* bytes_to_utf8(const U8 *s, STRLEN *len)
+
+=for hackers
+Found in file utf8.c
+
+=item ibcmp_utf8
+X<ibcmp_utf8>
+
+Return true if the strings s1 and s2 differ case-insensitively, false
+if not (if they are equal case-insensitively). If u1 is true, the
+string s1 is assumed to be in UTF-8-encoded Unicode. If u2 is true,
+the string s2 is assumed to be in UTF-8-encoded Unicode. If u1 or u2
+are false, the respective string is assumed to be in native 8-bit
+encoding.
+
+If the pe1 and pe2 are non-NULL, the scanning pointers will be copied
+in there (they will point at the beginning of the I<next> character).
+If the pointers behind pe1 or pe2 are non-NULL, they are the end
+pointers beyond which scanning will not continue under any
+circumstances. If the byte lengths l1 and l2 are non-zero, s1+l1 and
+s2+l2 will be used as goal end pointers that will also stop the scan,
+and which qualify towards defining a successful match: all the scans
+that define an explicit length must reach their goal pointers for
+a match to succeed).
+
+For case-insensitiveness, the "casefolding" of Unicode is used
+instead of upper/lowercasing both the characters, see
+http://www.unicode.org/unicode/reports/tr21/ (Case Mappings).
+
+ I32 ibcmp_utf8(const char *s1, char **pe1, UV l1, bool u1, const char *s2, char **pe2, UV l2, bool u2)
+
+=for hackers
+Found in file utf8.c
+
+=item is_ascii_string
+X<is_ascii_string>
+
+Returns true if first C<len> bytes of the given string are ASCII (i.e. none
+of them even raise the question of UTF-8-ness).
+
+See also is_utf8_string(), is_utf8_string_loclen(), and is_utf8_string_loc().
+
+ bool is_ascii_string(const U8 *s, STRLEN len)
+
+=for hackers
+Found in file utf8.c
+
+=item is_utf8_char
+X<is_utf8_char>
+
+Tests if some arbitrary number of bytes begins in a valid UTF-8
+character. Note that an INVARIANT (i.e. ASCII on non-EBCDIC machines)
+character is a valid UTF-8 character. The actual number of bytes in the UTF-8
+character will be returned if it is valid, otherwise 0.
+
+ STRLEN is_utf8_char(const U8 *s)
+
+=for hackers
+Found in file utf8.c
+
+=item is_utf8_string
+X<is_utf8_string>
+
+Returns true if first C<len> bytes of the given string form a valid
+UTF-8 string, false otherwise. Note that 'a valid UTF-8 string' does
+not mean 'a string that contains code points above 0x7F encoded in UTF-8'
+because a valid ASCII string is a valid UTF-8 string.
+
+See also is_ascii_string(), is_utf8_string_loclen(), and is_utf8_string_loc().
+
+ bool is_utf8_string(const U8 *s, STRLEN len)
+
+=for hackers
+Found in file utf8.c
+
+=item is_utf8_string_loc
+X<is_utf8_string_loc>
+
+Like is_utf8_string() but stores the location of the failure (in the
+case of "utf8ness failure") or the location s+len (in the case of
+"utf8ness success") in the C<ep>.
+
+See also is_utf8_string_loclen() and is_utf8_string().
+
+ bool is_utf8_string_loc(const U8 *s, STRLEN len, const U8 **p)
+
+=for hackers
+Found in file utf8.c
+
+=item is_utf8_string_loclen
+X<is_utf8_string_loclen>
+
+Like is_utf8_string() but stores the location of the failure (in the
+case of "utf8ness failure") or the location s+len (in the case of
+"utf8ness success") in the C<ep>, and the number of UTF-8
+encoded characters in the C<el>.
+
+See also is_utf8_string_loc() and is_utf8_string().
+
+ bool is_utf8_string_loclen(const U8 *s, STRLEN len, const U8 **ep, STRLEN *el)
+
+=for hackers
+Found in file utf8.c
+
+=item pv_uni_display
+X<pv_uni_display>
+
+Build to the scalar dsv a displayable version of the string spv,
+length len, the displayable version being at most pvlim bytes long
+(if longer, the rest is truncated and "..." will be appended).
+
+The flags argument can have UNI_DISPLAY_ISPRINT set to display
+isPRINT()able characters as themselves, UNI_DISPLAY_BACKSLASH
+to display the \\[nrfta\\] as the backslashed versions (like '\n')
+(UNI_DISPLAY_BACKSLASH is preferred over UNI_DISPLAY_ISPRINT for \\).
+UNI_DISPLAY_QQ (and its alias UNI_DISPLAY_REGEX) have both
+UNI_DISPLAY_BACKSLASH and UNI_DISPLAY_ISPRINT turned on.
+
+The pointer to the PV of the dsv is returned.
+
+ char* pv_uni_display(SV *dsv, const U8 *spv, STRLEN len, STRLEN pvlim, UV flags)
+
+=for hackers
+Found in file utf8.c
+
+=item sv_cat_decode
+X<sv_cat_decode>
+
+The encoding is assumed to be an Encode object, the PV of the ssv is
+assumed to be octets in that encoding and decoding the input starts
+from the position which (PV + *offset) pointed to. The dsv will be
+concatenated the decoded UTF-8 string from ssv. Decoding will terminate
+when the string tstr appears in decoding output or the input ends on
+the PV of the ssv. The value which the offset points will be modified
+to the last input position on the ssv.
+
+Returns TRUE if the terminator was found, else returns FALSE.
+
+ bool sv_cat_decode(SV* dsv, SV *encoding, SV *ssv, int *offset, char* tstr, int tlen)
+
+=for hackers
+Found in file sv.c
+
+=item sv_recode_to_utf8
+X<sv_recode_to_utf8>
+
+The encoding is assumed to be an Encode object, on entry the PV
+of the sv is assumed to be octets in that encoding, and the sv
+will be converted into Unicode (and UTF-8).
+
+If the sv already is UTF-8 (or if it is not POK), or if the encoding
+is not a reference, nothing is done to the sv. If the encoding is not
+an C<Encode::XS> Encoding object, bad things will happen.
+(See F<lib/encoding.pm> and L<Encode>).
+
+The PV of the sv is returned.
+
+ char* sv_recode_to_utf8(SV* sv, SV *encoding)
+
+=for hackers
+Found in file sv.c
+
+=item sv_uni_display
+X<sv_uni_display>
+
+Build to the scalar dsv a displayable version of the scalar sv,
+the displayable version being at most pvlim bytes long
+(if longer, the rest is truncated and "..." will be appended).
+
+The flags argument is as in pv_uni_display().
+
+The pointer to the PV of the dsv is returned.
+
+ char* sv_uni_display(SV *dsv, SV *ssv, STRLEN pvlim, UV flags)
+
+=for hackers
+Found in file utf8.c
+
+=item to_utf8_case
+X<to_utf8_case>
+
+The "p" contains the pointer to the UTF-8 string encoding
+the character that is being converted.
+
+The "ustrp" is a pointer to the character buffer to put the
+conversion result to. The "lenp" is a pointer to the length
+of the result.
+
+The "swashp" is a pointer to the swash to use.
+
+Both the special and normal mappings are stored lib/unicore/To/Foo.pl,
+and loaded by SWASHNEW, using lib/utf8_heavy.pl. The special (usually,
+but not always, a multicharacter mapping), is tried first.
+
+The "special" is a string like "utf8::ToSpecLower", which means the
+hash %utf8::ToSpecLower. The access to the hash is through
+Perl_to_utf8_case().
+
+The "normal" is a string like "ToLower" which means the swash
+%utf8::ToLower.
+
+ UV to_utf8_case(const U8 *p, U8* ustrp, STRLEN *lenp, SV **swashp, const char *normal, const char *special)
+
+=for hackers
+Found in file utf8.c
+
+=item to_utf8_fold
+X<to_utf8_fold>
+
+Convert the UTF-8 encoded character at p to its foldcase version and
+store that in UTF-8 in ustrp and its length in bytes in lenp. Note
+that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the
+foldcase version may be longer than the original character (up to
+three characters).
+
+The first character of the foldcased version is returned
+(but note, as explained above, that there may be more.)
+
+ UV to_utf8_fold(const U8 *p, U8* ustrp, STRLEN *lenp)
+
+=for hackers
+Found in file utf8.c
+
+=item to_utf8_lower
+X<to_utf8_lower>
+
+Convert the UTF-8 encoded character at p to its lowercase version and
+store that in UTF-8 in ustrp and its length in bytes in lenp. Note
+that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the
+lowercase version may be longer than the original character.
+
+The first character of the lowercased version is returned
+(but note, as explained above, that there may be more.)
+
+ UV to_utf8_lower(const U8 *p, U8* ustrp, STRLEN *lenp)
+
+=for hackers
+Found in file utf8.c
+
+=item to_utf8_title
+X<to_utf8_title>
+
+Convert the UTF-8 encoded character at p to its titlecase version and
+store that in UTF-8 in ustrp and its length in bytes in lenp. Note
+that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since the
+titlecase version may be longer than the original character.
+
+The first character of the titlecased version is returned
+(but note, as explained above, that there may be more.)
+
+ UV to_utf8_title(const U8 *p, U8* ustrp, STRLEN *lenp)
+
+=for hackers
+Found in file utf8.c
+
+=item to_utf8_upper
+X<to_utf8_upper>
+
+Convert the UTF-8 encoded character at p to its uppercase version and
+store that in UTF-8 in ustrp and its length in bytes in lenp. Note
+that the ustrp needs to be at least UTF8_MAXBYTES_CASE+1 bytes since
+the uppercase version may be longer than the original character.
+
+The first character of the uppercased version is returned
+(but note, as explained above, that there may be more.)
+
+ UV to_utf8_upper(const U8 *p, U8* ustrp, STRLEN *lenp)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8n_to_uvchr
+X<utf8n_to_uvchr>
+
+flags
+
+Returns the native character value of the first character in the string
+C<s>
+which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
+length, in bytes, of that character.
+
+Allows length and flags to be passed to low level routine.
+
+ UV utf8n_to_uvchr(const U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8n_to_uvuni
+X<utf8n_to_uvuni>
+
+Bottom level UTF-8 decode routine.
+Returns the Unicode code point value of the first character in the string C<s>
+which is assumed to be in UTF-8 encoding and no longer than C<curlen>;
+C<retlen> will be set to the length, in bytes, of that character.
+
+If C<s> does not point to a well-formed UTF-8 character, the behaviour
+is dependent on the value of C<flags>: if it contains UTF8_CHECK_ONLY,
+it is assumed that the caller will raise a warning, and this function
+will silently just set C<retlen> to C<-1> and return zero. If the
+C<flags> does not contain UTF8_CHECK_ONLY, warnings about
+malformations will be given, C<retlen> will be set to the expected
+length of the UTF-8 character in bytes, and zero will be returned.
+
+The C<flags> can also contain various flags to allow deviations from
+the strict UTF-8 encoding (see F<utf8.h>).
+
+Most code should use utf8_to_uvchr() rather than call this directly.
+
+ UV utf8n_to_uvuni(const U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_distance
+X<utf8_distance>
+
+Returns the number of UTF-8 characters between the UTF-8 pointers C<a>
+and C<b>.
+
+WARNING: use only if you *know* that the pointers point inside the
+same UTF-8 buffer.
+
+ IV utf8_distance(const U8 *a, const U8 *b)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_hop
+X<utf8_hop>
+
+Return the UTF-8 pointer C<s> displaced by C<off> characters, either
+forward or backward.
+
+WARNING: do not use the following unless you *know* C<off> is within
+the UTF-8 data pointed to by C<s> *and* that on entry C<s> is aligned
+on the first byte of character or just after the last byte of a character.
+
+ U8* utf8_hop(const U8 *s, I32 off)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_length
+X<utf8_length>
+
+Return the length of the UTF-8 char encoded string C<s> in characters.
+Stops at C<e> (inclusive). If C<e E<lt> s> or if the scan would end
+up past C<e>, croaks.
+
+ STRLEN utf8_length(const U8* s, const U8 *e)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_to_bytes
+X<utf8_to_bytes>
+
+Converts a string C<s> of length C<len> from UTF-8 into native byte encoding.
+Unlike C<bytes_to_utf8>, this over-writes the original string, and
+updates len to contain the new length.
+Returns zero on failure, setting C<len> to -1.
+
+If you need a copy of the string, see C<bytes_from_utf8>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ U8* utf8_to_bytes(U8 *s, STRLEN *len)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_to_uvchr
+X<utf8_to_uvchr>
+
+Returns the native character value of the first character in the string C<s>
+which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
+length, in bytes, of that character.
+
+If C<s> does not point to a well-formed UTF-8 character, zero is
+returned and retlen is set, if possible, to -1.
+
+ UV utf8_to_uvchr(const U8 *s, STRLEN *retlen)
+
+=for hackers
+Found in file utf8.c
+
+=item utf8_to_uvuni
+X<utf8_to_uvuni>
+
+Returns the Unicode code point of the first character in the string C<s>
+which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
+length, in bytes, of that character.
+
+This function should only be used when the returned UV is considered
+an index into the Unicode semantic tables (e.g. swashes).
+
+If C<s> does not point to a well-formed UTF-8 character, zero is
+returned and retlen is set, if possible, to -1.
+
+ UV utf8_to_uvuni(const U8 *s, STRLEN *retlen)
+
+=for hackers
+Found in file utf8.c
+
+=item uvchr_to_utf8
+X<uvchr_to_utf8>
+
+Adds the UTF-8 representation of the Native codepoint C<uv> to the end
+of the string C<d>; C<d> should be have at least C<UTF8_MAXBYTES+1> free
+bytes available. The return value is the pointer to the byte after the
+end of the new character. In other words,
+
+ d = uvchr_to_utf8(d, uv);
+
+is the recommended wide native character-aware way of saying
+
+ *(d++) = uv;
+
+ U8* uvchr_to_utf8(U8 *d, UV uv)
+
+=for hackers
+Found in file utf8.c
+
+=item uvuni_to_utf8_flags
+X<uvuni_to_utf8_flags>
+
+Adds the UTF-8 representation of the Unicode codepoint C<uv> to the end
+of the string C<d>; C<d> should be have at least C<UTF8_MAXBYTES+1> free
+bytes available. The return value is the pointer to the byte after the
+end of the new character. In other words,
+
+ d = uvuni_to_utf8_flags(d, uv, flags);
+
+or, in most cases,
+
+ d = uvuni_to_utf8(d, uv);
+
+(which is equivalent to)
+
+ d = uvuni_to_utf8_flags(d, uv, 0);
+
+is the recommended Unicode-aware way of saying
+
+ *(d++) = uv;
+
+ U8* uvuni_to_utf8_flags(U8 *d, UV uv, UV flags)
+
+=for hackers
+Found in file utf8.c
+
+
+=back
+
+=head1 Variables created by C<xsubpp> and C<xsubpp> internal functions
+
+=over 8
+
+=item ax
+X<ax>
+
+Variable which is setup by C<xsubpp> to indicate the stack base offset,
+used by the C<ST>, C<XSprePUSH> and C<XSRETURN> macros. The C<dMARK> macro
+must be called prior to setup the C<MARK> variable.
+
+ I32 ax
+
+=for hackers
+Found in file XSUB.h
+
+=item CLASS
+X<CLASS>
+
+Variable which is setup by C<xsubpp> to indicate the
+class name for a C++ XS constructor. This is always a C<char*>. See C<THIS>.
+
+ char* CLASS
+
+=for hackers
+Found in file XSUB.h
+
+=item dAX
+X<dAX>
+
+Sets up the C<ax> variable.
+This is usually handled automatically by C<xsubpp> by calling C<dXSARGS>.
+
+ dAX;
+
+=for hackers
+Found in file XSUB.h
+
+=item dAXMARK
+X<dAXMARK>
+
+Sets up the C<ax> variable and stack marker variable C<mark>.
+This is usually handled automatically by C<xsubpp> by calling C<dXSARGS>.
+
+ dAXMARK;
+
+=for hackers
+Found in file XSUB.h
+
+=item dITEMS
+X<dITEMS>
+
+Sets up the C<items> variable.
+This is usually handled automatically by C<xsubpp> by calling C<dXSARGS>.
+
+ dITEMS;
+
+=for hackers
+Found in file XSUB.h
+
+=item dUNDERBAR
+X<dUNDERBAR>
+
+Sets up the C<padoff_du> variable for an XSUB that wishes to use
+C<UNDERBAR>.
+
+ dUNDERBAR;
+
+=for hackers
+Found in file XSUB.h
+
+=item dXSARGS
+X<dXSARGS>
+
+Sets up stack and mark pointers for an XSUB, calling dSP and dMARK.
+Sets up the C<ax> and C<items> variables by calling C<dAX> and C<dITEMS>.
+This is usually handled automatically by C<xsubpp>.
+
+ dXSARGS;
+
+=for hackers
+Found in file XSUB.h
+
+=item dXSI32
+X<dXSI32>
+
+Sets up the C<ix> variable for an XSUB which has aliases. This is usually
+handled automatically by C<xsubpp>.
+
+ dXSI32;
+
+=for hackers
+Found in file XSUB.h
+
+=item items
+X<items>
+
+Variable which is setup by C<xsubpp> to indicate the number of
+items on the stack. See L<perlxs/"Variable-length Parameter Lists">.
+
+ I32 items
+
+=for hackers
+Found in file XSUB.h
+
+=item ix
+X<ix>
+
+Variable which is setup by C<xsubpp> to indicate which of an
+XSUB's aliases was used to invoke it. See L<perlxs/"The ALIAS: Keyword">.
+
+ I32 ix
+
+=for hackers
+Found in file XSUB.h
+
+=item newXSproto
+X<newXSproto>
+
+Used by C<xsubpp> to hook up XSUBs as Perl subs. Adds Perl prototypes to
+the subs.
+
+=for hackers
+Found in file XSUB.h
+
+=item RETVAL
+X<RETVAL>
+
+Variable which is setup by C<xsubpp> to hold the return value for an
+XSUB. This is always the proper type for the XSUB. See
+L<perlxs/"The RETVAL Variable">.
+
+ (whatever) RETVAL
+
+=for hackers
+Found in file XSUB.h
+
+=item ST
+X<ST>
+
+Used to access elements on the XSUB's stack.
+
+ SV* ST(int ix)
+
+=for hackers
+Found in file XSUB.h
+
+=item THIS
+X<THIS>
+
+Variable which is setup by C<xsubpp> to designate the object in a C++
+XSUB. This is always the proper type for the C++ object. See C<CLASS> and
+L<perlxs/"Using XS With C++">.
+
+ (whatever) THIS
+
+=for hackers
+Found in file XSUB.h
+
+=item UNDERBAR
+X<UNDERBAR>
+
+The SV* corresponding to the $_ variable. Works even if there
+is a lexical $_ in scope.
+
+=for hackers
+Found in file XSUB.h
+
+=item XS
+X<XS>
+
+Macro to declare an XSUB and its C parameter list. This is handled by
+C<xsubpp>.
+
+=for hackers
+Found in file XSUB.h
+
+=item XS_VERSION
+X<XS_VERSION>
+
+The version identifier for an XS module. This is usually
+handled automatically by C<ExtUtils::MakeMaker>. See C<XS_VERSION_BOOTCHECK>.
+
+=for hackers
+Found in file XSUB.h
+
+=item XS_VERSION_BOOTCHECK
+X<XS_VERSION_BOOTCHECK>
+
+Macro to verify that a PM module's $VERSION variable matches the XS
+module's C<XS_VERSION> variable. This is usually handled automatically by
+C<xsubpp>. See L<perlxs/"The VERSIONCHECK: Keyword">.
+
+ XS_VERSION_BOOTCHECK;
+
+=for hackers
+Found in file XSUB.h
+
+
+=back
+
+=head1 Warning and Dieing
+
+=over 8
+
+=item croak
+X<croak>
+
+This is the XSUB-writer's interface to Perl's C<die> function.
+Normally call this function the same way you call the C C<printf>
+function. Calling C<croak> returns control directly to Perl,
+sidestepping the normal C order of execution. See C<warn>.
+
+If you want to throw an exception object, assign the object to
+C<$@> and then pass C<NULL> to croak():
+
+ errsv = get_sv("@", GV_ADD);
+ sv_setsv(errsv, exception_object);
+ croak(NULL);
+
+ void croak(const char* pat, ...)
+
+=for hackers
+Found in file util.c
+
+=item warn
+X<warn>
+
+This is the XSUB-writer's interface to Perl's C<warn> function. Call this
+function the same way you call the C C<printf> function. See C<croak>.
+
+ void warn(const char* pat, ...)
+
+=for hackers
+Found in file util.c
+
+
+=back
+
+=head1 Undocumented functions
+
+These functions are currently undocumented:
+
+=over
+
+=item GetVars
+X<GetVars>
+
+=item Gv_AMupdate
+X<Gv_AMupdate>
+
+=item PerlIO_clearerr
+X<PerlIO_clearerr>
+
+=item PerlIO_close
+X<PerlIO_close>
+
+=item PerlIO_context_layers
+X<PerlIO_context_layers>
+
+=item PerlIO_eof
+X<PerlIO_eof>
+
+=item PerlIO_error
+X<PerlIO_error>
+
+=item PerlIO_fileno
+X<PerlIO_fileno>
+
+=item PerlIO_fill
+X<PerlIO_fill>
+
+=item PerlIO_flush
+X<PerlIO_flush>
+
+=item PerlIO_get_base
+X<PerlIO_get_base>
+
+=item PerlIO_get_bufsiz
+X<PerlIO_get_bufsiz>
+
+=item PerlIO_get_cnt
+X<PerlIO_get_cnt>
+
+=item PerlIO_get_ptr
+X<PerlIO_get_ptr>
+
+=item PerlIO_read
+X<PerlIO_read>
+
+=item PerlIO_seek
+X<PerlIO_seek>
+
+=item PerlIO_set_cnt
+X<PerlIO_set_cnt>
+
+=item PerlIO_set_ptrcnt
+X<PerlIO_set_ptrcnt>
+
+=item PerlIO_setlinebuf
+X<PerlIO_setlinebuf>
+
+=item PerlIO_stderr
+X<PerlIO_stderr>
+
+=item PerlIO_stdin
+X<PerlIO_stdin>
+
+=item PerlIO_stdout
+X<PerlIO_stdout>
+
+=item PerlIO_tell
+X<PerlIO_tell>
+
+=item PerlIO_unread
+X<PerlIO_unread>
+
+=item PerlIO_write
+X<PerlIO_write>
+
+=item Slab_Alloc
+X<Slab_Alloc>
+
+=item Slab_Free
+X<Slab_Free>
+
+=item amagic_call
+X<amagic_call>
+
+=item any_dup
+X<any_dup>
+
+=item apply_attrs_string
+X<apply_attrs_string>
+
+=item atfork_lock
+X<atfork_lock>
+
+=item atfork_unlock
+X<atfork_unlock>
+
+=item av_arylen_p
+X<av_arylen_p>
+
+=item av_iter_p
+X<av_iter_p>
+
+=item block_gimme
+X<block_gimme>
+
+=item call_atexit
+X<call_atexit>
+
+=item call_list
+X<call_list>
+
+=item calloc
+X<calloc>
+
+=item cast_i32
+X<cast_i32>
+
+=item cast_iv
+X<cast_iv>
+
+=item cast_ulong
+X<cast_ulong>
+
+=item cast_uv
+X<cast_uv>
+
+=item ck_warner
+X<ck_warner>
+
+=item ck_warner_d
+X<ck_warner_d>
+
+=item ckwarn
+X<ckwarn>
+
+=item ckwarn_d
+X<ckwarn_d>
+
+=item croak_nocontext
+X<croak_nocontext>
+
+=item csighandler
+X<csighandler>
+
+=item custom_op_desc
+X<custom_op_desc>
+
+=item custom_op_name
+X<custom_op_name>
+
+=item cx_dump
+X<cx_dump>
+
+=item cx_dup
+X<cx_dup>
+
+=item cxinc
+X<cxinc>
+
+=item deb
+X<deb>
+
+=item deb_nocontext
+X<deb_nocontext>
+
+=item debop
+X<debop>
+
+=item debprofdump
+X<debprofdump>
+
+=item debstack
+X<debstack>
+
+=item debstackptrs
+X<debstackptrs>
+
+=item delimcpy
+X<delimcpy>
+
+=item despatch_signals
+X<despatch_signals>
+
+=item die
+X<die>
+
+=item die_nocontext
+X<die_nocontext>
+
+=item dirp_dup
+X<dirp_dup>
+
+=item do_aspawn
+X<do_aspawn>
+
+=item do_binmode
+X<do_binmode>
+
+=item do_close
+X<do_close>
+
+=item do_gv_dump
+X<do_gv_dump>
+
+=item do_gvgv_dump
+X<do_gvgv_dump>
+
+=item do_hv_dump
+X<do_hv_dump>
+
+=item do_join
+X<do_join>
+
+=item do_magic_dump
+X<do_magic_dump>
+
+=item do_op_dump
+X<do_op_dump>
+
+=item do_open
+X<do_open>
+
+=item do_open9
+X<do_open9>
+
+=item do_openn
+X<do_openn>
+
+=item do_pmop_dump
+X<do_pmop_dump>
+
+=item do_spawn
+X<do_spawn>
+
+=item do_spawn_nowait
+X<do_spawn_nowait>
+
+=item do_sprintf
+X<do_sprintf>
+
+=item do_sv_dump
+X<do_sv_dump>
+
+=item doing_taint
+X<doing_taint>
+
+=item doref
+X<doref>
+
+=item dounwind
+X<dounwind>
+
+=item dowantarray
+X<dowantarray>
+
+=item dump_all
+X<dump_all>
+
+=item dump_eval
+X<dump_eval>
+
+=item dump_fds
+X<dump_fds>
+
+=item dump_form
+X<dump_form>
+
+=item dump_indent
+X<dump_indent>
+
+=item dump_mstats
+X<dump_mstats>
+
+=item dump_packsubs
+X<dump_packsubs>
+
+=item dump_sub
+X<dump_sub>
+
+=item dump_vindent
+X<dump_vindent>
+
+=item fetch_cop_label
+X<fetch_cop_label>
+
+=item filter_add
+X<filter_add>
+
+=item filter_del
+X<filter_del>
+
+=item filter_read
+X<filter_read>
+
+=item find_rundefsvoffset
+X<find_rundefsvoffset>
+
+=item form_nocontext
+X<form_nocontext>
+
+=item fp_dup
+X<fp_dup>
+
+=item fprintf_nocontext
+X<fprintf_nocontext>
+
+=item free_global_struct
+X<free_global_struct>
+
+=item free_tmps
+X<free_tmps>
+
+=item get_context
+X<get_context>
+
+=item get_mstats
+X<get_mstats>
+
+=item get_op_descs
+X<get_op_descs>
+
+=item get_op_names
+X<get_op_names>
+
+=item get_ppaddr
+X<get_ppaddr>
+
+=item get_vtbl
+X<get_vtbl>
+
+=item gp_dup
+X<gp_dup>
+
+=item gp_free
+X<gp_free>
+
+=item gp_ref
+X<gp_ref>
+
+=item gv_AVadd
+X<gv_AVadd>
+
+=item gv_HVadd
+X<gv_HVadd>
+
+=item gv_IOadd
+X<gv_IOadd>
+
+=item gv_SVadd
+X<gv_SVadd>
+
+=item gv_add_by_type
+X<gv_add_by_type>
+
+=item gv_autoload4
+X<gv_autoload4>
+
+=item gv_check
+X<gv_check>
+
+=item gv_dump
+X<gv_dump>
+
+=item gv_efullname
+X<gv_efullname>
+
+=item gv_efullname3
+X<gv_efullname3>
+
+=item gv_efullname4
+X<gv_efullname4>
+
+=item gv_fetchfile
+X<gv_fetchfile>
+
+=item gv_fetchfile_flags
+X<gv_fetchfile_flags>
+
+=item gv_fetchmethod_flags
+X<gv_fetchmethod_flags>
+
+=item gv_fetchpv
+X<gv_fetchpv>
+
+=item gv_fetchpvn_flags
+X<gv_fetchpvn_flags>
+
+=item gv_fetchsv
+X<gv_fetchsv>
+
+=item gv_fullname
+X<gv_fullname>
+
+=item gv_fullname3
+X<gv_fullname3>
+
+=item gv_fullname4
+X<gv_fullname4>
+
+=item gv_handler
+X<gv_handler>
+
+=item gv_init
+X<gv_init>
+
+=item gv_name_set
+X<gv_name_set>
+
+=item he_dup
+X<he_dup>
+
+=item hek_dup
+X<hek_dup>
+
+=item hv_common
+X<hv_common>
+
+=item hv_common_key_len
+X<hv_common_key_len>
+
+=item hv_delayfree_ent
+X<hv_delayfree_ent>
+
+=item hv_eiter_p
+X<hv_eiter_p>
+
+=item hv_eiter_set
+X<hv_eiter_set>
+
+=item hv_free_ent
+X<hv_free_ent>
+
+=item hv_ksplit
+X<hv_ksplit>
+
+=item hv_name_set
+X<hv_name_set>
+
+=item hv_placeholders_get
+X<hv_placeholders_get>
+
+=item hv_placeholders_p
+X<hv_placeholders_p>
+
+=item hv_placeholders_set
+X<hv_placeholders_set>
+
+=item hv_riter_p
+X<hv_riter_p>
+
+=item hv_riter_set
+X<hv_riter_set>
+
+=item hv_store_flags
+X<hv_store_flags>
+
+=item ibcmp
+X<ibcmp>
+
+=item ibcmp_locale
+X<ibcmp_locale>
+
+=item init_global_struct
+X<init_global_struct>
+
+=item init_i18nl10n
+X<init_i18nl10n>
+
+=item init_i18nl14n
+X<init_i18nl14n>
+
+=item init_stacks
+X<init_stacks>
+
+=item init_tm
+X<init_tm>
+
+=item instr
+X<instr>
+
+=item is_lvalue_sub
+X<is_lvalue_sub>
+
+=item is_uni_alnum
+X<is_uni_alnum>
+
+=item is_uni_alnum_lc
+X<is_uni_alnum_lc>
+
+=item is_uni_alpha
+X<is_uni_alpha>
+
+=item is_uni_alpha_lc
+X<is_uni_alpha_lc>
+
+=item is_uni_ascii
+X<is_uni_ascii>
+
+=item is_uni_ascii_lc
+X<is_uni_ascii_lc>
+
+=item is_uni_cntrl
+X<is_uni_cntrl>
+
+=item is_uni_cntrl_lc
+X<is_uni_cntrl_lc>
+
+=item is_uni_digit
+X<is_uni_digit>
+
+=item is_uni_digit_lc
+X<is_uni_digit_lc>
+
+=item is_uni_graph
+X<is_uni_graph>
+
+=item is_uni_graph_lc
+X<is_uni_graph_lc>
+
+=item is_uni_idfirst
+X<is_uni_idfirst>
+
+=item is_uni_idfirst_lc
+X<is_uni_idfirst_lc>
+
+=item is_uni_lower
+X<is_uni_lower>
+
+=item is_uni_lower_lc
+X<is_uni_lower_lc>
+
+=item is_uni_print
+X<is_uni_print>
+
+=item is_uni_print_lc
+X<is_uni_print_lc>
+
+=item is_uni_punct
+X<is_uni_punct>
+
+=item is_uni_punct_lc
+X<is_uni_punct_lc>
+
+=item is_uni_space
+X<is_uni_space>
+
+=item is_uni_space_lc
+X<is_uni_space_lc>
+
+=item is_uni_upper
+X<is_uni_upper>
+
+=item is_uni_upper_lc
+X<is_uni_upper_lc>
+
+=item is_uni_xdigit
+X<is_uni_xdigit>
+
+=item is_uni_xdigit_lc
+X<is_uni_xdigit_lc>
+
+=item is_utf8_alnum
+X<is_utf8_alnum>
+
+=item is_utf8_alpha
+X<is_utf8_alpha>
+
+=item is_utf8_ascii
+X<is_utf8_ascii>
+
+=item is_utf8_cntrl
+X<is_utf8_cntrl>
+
+=item is_utf8_digit
+X<is_utf8_digit>
+
+=item is_utf8_graph
+X<is_utf8_graph>
+
+=item is_utf8_idcont
+X<is_utf8_idcont>
+
+=item is_utf8_idfirst
+X<is_utf8_idfirst>
+
+=item is_utf8_lower
+X<is_utf8_lower>
+
+=item is_utf8_mark
+X<is_utf8_mark>
+
+=item is_utf8_perl_space
+X<is_utf8_perl_space>
+
+=item is_utf8_perl_word
+X<is_utf8_perl_word>
+
+=item is_utf8_posix_digit
+X<is_utf8_posix_digit>
+
+=item is_utf8_print
+X<is_utf8_print>
+
+=item is_utf8_punct
+X<is_utf8_punct>
+
+=item is_utf8_space
+X<is_utf8_space>
+
+=item is_utf8_upper
+X<is_utf8_upper>
+
+=item is_utf8_xdigit
+X<is_utf8_xdigit>
+
+=item leave_scope
+X<leave_scope>
+
+=item load_module_nocontext
+X<load_module_nocontext>
+
+=item magic_dump
+X<magic_dump>
+
+=item malloc
+X<malloc>
+
+=item markstack_grow
+X<markstack_grow>
+
+=item mess
+X<mess>
+
+=item mess_nocontext
+X<mess_nocontext>
+
+=item mfree
+X<mfree>
+
+=item mg_dup
+X<mg_dup>
+
+=item mg_size
+X<mg_size>
+
+=item mini_mktime
+X<mini_mktime>
+
+=item moreswitches
+X<moreswitches>
+
+=item mro_get_from_name
+X<mro_get_from_name>
+
+=item mro_get_private_data
+X<mro_get_private_data>
+
+=item mro_register
+X<mro_register>
+
+=item mro_set_mro
+X<mro_set_mro>
+
+=item mro_set_private_data
+X<mro_set_private_data>
+
+=item my_atof
+X<my_atof>
+
+=item my_atof2
+X<my_atof2>
+
+=item my_bcopy
+X<my_bcopy>
+
+=item my_bzero
+X<my_bzero>
+
+=item my_chsize
+X<my_chsize>
+
+=item my_cxt_index
+X<my_cxt_index>
+
+=item my_cxt_init
+X<my_cxt_init>
+
+=item my_dirfd
+X<my_dirfd>
+
+=item my_exit
+X<my_exit>
+
+=item my_failure_exit
+X<my_failure_exit>
+
+=item my_fflush_all
+X<my_fflush_all>
+
+=item my_fork
+X<my_fork>
+
+=item my_htonl
+X<my_htonl>
+
+=item my_lstat
+X<my_lstat>
+
+=item my_memcmp
+X<my_memcmp>
+
+=item my_memset
+X<my_memset>
+
+=item my_ntohl
+X<my_ntohl>
+
+=item my_pclose
+X<my_pclose>
+
+=item my_popen
+X<my_popen>
+
+=item my_popen_list
+X<my_popen_list>
+
+=item my_setenv
+X<my_setenv>
+
+=item my_socketpair
+X<my_socketpair>
+
+=item my_stat
+X<my_stat>
+
+=item my_strftime
+X<my_strftime>
+
+=item my_strlcat
+X<my_strlcat>
+
+=item my_strlcpy
+X<my_strlcpy>
+
+=item my_swap
+X<my_swap>
+
+=item newANONATTRSUB
+X<newANONATTRSUB>
+
+=item newANONHASH
+X<newANONHASH>
+
+=item newANONLIST
+X<newANONLIST>
+
+=item newANONSUB
+X<newANONSUB>
+
+=item newASSIGNOP
+X<newASSIGNOP>
+
+=item newATTRSUB
+X<newATTRSUB>
+
+=item newAVREF
+X<newAVREF>
+
+=item newBINOP
+X<newBINOP>
+
+=item newCONDOP
+X<newCONDOP>
+
+=item newCVREF
+X<newCVREF>
+
+=item newFORM
+X<newFORM>
+
+=item newFOROP
+X<newFOROP>
+
+=item newGIVENOP
+X<newGIVENOP>
+
+=item newGVOP
+X<newGVOP>
+
+=item newGVREF
+X<newGVREF>
+
+=item newGVgen
+X<newGVgen>
+
+=item newHVREF
+X<newHVREF>
+
+=item newHVhv
+X<newHVhv>
+
+=item newIO
+X<newIO>
+
+=item newLISTOP
+X<newLISTOP>
+
+=item newLOGOP
+X<newLOGOP>
+
+=item newLOOPEX
+X<newLOOPEX>
+
+=item newLOOPOP
+X<newLOOPOP>
+
+=item newMYSUB
+X<newMYSUB>
+
+=item newNULLLIST
+X<newNULLLIST>
+
+=item newOP
+X<newOP>
+
+=item newPADOP
+X<newPADOP>
+
+=item newPMOP
+X<newPMOP>
+
+=item newPROG
+X<newPROG>
+
+=item newPVOP
+X<newPVOP>
+
+=item newRANGE
+X<newRANGE>
+
+=item newRV
+X<newRV>
+
+=item newSLICEOP
+X<newSLICEOP>
+
+=item newSTATEOP
+X<newSTATEOP>
+
+=item newSUB
+X<newSUB>
+
+=item newSVOP
+X<newSVOP>
+
+=item newSVREF
+X<newSVREF>
+
+=item newSVpvf_nocontext
+X<newSVpvf_nocontext>
+
+=item newUNOP
+X<newUNOP>
+
+=item newWHENOP
+X<newWHENOP>
+
+=item newWHILEOP
+X<newWHILEOP>
+
+=item newXS_flags
+X<newXS_flags>
+
+=item new_collate
+X<new_collate>
+
+=item new_ctype
+X<new_ctype>
+
+=item new_numeric
+X<new_numeric>
+
+=item new_stackinfo
+X<new_stackinfo>
+
+=item ninstr
+X<ninstr>
+
+=item op_dump
+X<op_dump>
+
+=item op_free
+X<op_free>
+
+=item op_null
+X<op_null>
+
+=item op_refcnt_lock
+X<op_refcnt_lock>
+
+=item op_refcnt_unlock
+X<op_refcnt_unlock>
+
+=item parser_dup
+X<parser_dup>
+
+=item perl_alloc_using
+X<perl_alloc_using>
+
+=item perl_clone_using
+X<perl_clone_using>
+
+=item pmop_dump
+X<pmop_dump>
+
+=item pop_scope
+X<pop_scope>
+
+=item pregcomp
+X<pregcomp>
+
+=item pregexec
+X<pregexec>
+
+=item pregfree
+X<pregfree>
+
+=item pregfree2
+X<pregfree2>
+
+=item printf_nocontext
+X<printf_nocontext>
+
+=item ptr_table_clear
+X<ptr_table_clear>
+
+=item ptr_table_fetch
+X<ptr_table_fetch>
+
+=item ptr_table_free
+X<ptr_table_free>
+
+=item ptr_table_new
+X<ptr_table_new>
+
+=item ptr_table_split
+X<ptr_table_split>
+
+=item ptr_table_store
+X<ptr_table_store>
+
+=item push_scope
+X<push_scope>
+
+=item re_compile
+X<re_compile>
+
+=item re_dup_guts
+X<re_dup_guts>
+
+=item re_intuit_start
+X<re_intuit_start>
+
+=item re_intuit_string
+X<re_intuit_string>
+
+=item realloc
+X<realloc>
+
+=item reentrant_free
+X<reentrant_free>
+
+=item reentrant_init
+X<reentrant_init>
+
+=item reentrant_retry
+X<reentrant_retry>
+
+=item reentrant_size
+X<reentrant_size>
+
+=item ref
+X<ref>
+
+=item reg_named_buff_all
+X<reg_named_buff_all>
+
+=item reg_named_buff_exists
+X<reg_named_buff_exists>
+
+=item reg_named_buff_fetch
+X<reg_named_buff_fetch>
+
+=item reg_named_buff_firstkey
+X<reg_named_buff_firstkey>
+
+=item reg_named_buff_nextkey
+X<reg_named_buff_nextkey>
+
+=item reg_named_buff_scalar
+X<reg_named_buff_scalar>
+
+=item regclass_swash
+X<regclass_swash>
+
+=item regdump
+X<regdump>
+
+=item regdupe_internal
+X<regdupe_internal>
+
+=item regexec_flags
+X<regexec_flags>
+
+=item regfree_internal
+X<regfree_internal>
+
+=item reginitcolors
+X<reginitcolors>
+
+=item regnext
+X<regnext>
+
+=item repeatcpy
+X<repeatcpy>
+
+=item rninstr
+X<rninstr>
+
+=item rsignal
+X<rsignal>
+
+=item rsignal_state
+X<rsignal_state>
+
+=item runops_debug
+X<runops_debug>
+
+=item runops_standard
+X<runops_standard>
+
+=item rvpv_dup
+X<rvpv_dup>
+
+=item safesyscalloc
+X<safesyscalloc>
+
+=item safesysfree
+X<safesysfree>
+
+=item safesysmalloc
+X<safesysmalloc>
+
+=item safesysrealloc
+X<safesysrealloc>
+
+=item save_I16
+X<save_I16>
+
+=item save_I32
+X<save_I32>
+
+=item save_I8
+X<save_I8>
+
+=item save_adelete
+X<save_adelete>
+
+=item save_aelem
+X<save_aelem>
+
+=item save_aelem_flags
+X<save_aelem_flags>
+
+=item save_alloc
+X<save_alloc>
+
+=item save_aptr
+X<save_aptr>
+
+=item save_ary
+X<save_ary>
+
+=item save_bool
+X<save_bool>
+
+=item save_clearsv
+X<save_clearsv>
+
+=item save_delete
+X<save_delete>
+
+=item save_destructor
+X<save_destructor>
+
+=item save_destructor_x
+X<save_destructor_x>
+
+=item save_freepv
+X<save_freepv>
+
+=item save_freesv
+X<save_freesv>
+
+=item save_generic_pvref
+X<save_generic_pvref>
+
+=item save_generic_svref
+X<save_generic_svref>
+
+=item save_gp
+X<save_gp>
+
+=item save_hash
+X<save_hash>
+
+=item save_hdelete
+X<save_hdelete>
+
+=item save_helem
+X<save_helem>
+
+=item save_helem_flags
+X<save_helem_flags>
+
+=item save_hptr
+X<save_hptr>
+
+=item save_int
+X<save_int>
+
+=item save_item
+X<save_item>
+
+=item save_iv
+X<save_iv>
+
+=item save_list
+X<save_list>
+
+=item save_long
+X<save_long>
+
+=item save_mortalizesv
+X<save_mortalizesv>
+
+=item save_nogv
+X<save_nogv>
+
+=item save_padsv_and_mortalize
+X<save_padsv_and_mortalize>
+
+=item save_pptr
+X<save_pptr>
+
+=item save_pushptr
+X<save_pushptr>
+
+=item save_re_context
+X<save_re_context>
+
+=item save_scalar
+X<save_scalar>
+
+=item save_set_svflags
+X<save_set_svflags>
+
+=item save_shared_pvref
+X<save_shared_pvref>
+
+=item save_sptr
+X<save_sptr>
+
+=item save_svref
+X<save_svref>
+
+=item save_vptr
+X<save_vptr>
+
+=item savestack_grow
+X<savestack_grow>
+
+=item savestack_grow_cnt
+X<savestack_grow_cnt>
+
+=item scan_num
+X<scan_num>
+
+=item scan_vstring
+X<scan_vstring>
+
+=item screaminstr
+X<screaminstr>
+
+=item seed
+X<seed>
+
+=item set_context
+X<set_context>
+
+=item set_numeric_local
+X<set_numeric_local>
+
+=item set_numeric_radix
+X<set_numeric_radix>
+
+=item set_numeric_standard
+X<set_numeric_standard>
+
+=item share_hek
+X<share_hek>
+
+=item si_dup
+X<si_dup>
+
+=item ss_dup
+X<ss_dup>
+
+=item stack_grow
+X<stack_grow>
+
+=item start_subparse
+X<start_subparse>
+
+=item stashpv_hvname_match
+X<stashpv_hvname_match>
+
+=item str_to_version
+X<str_to_version>
+
+=item sv_2iv
+X<sv_2iv>
+
+=item sv_2pv
+X<sv_2pv>
+
+=item sv_2uv
+X<sv_2uv>
+
+=item sv_catpvf_mg_nocontext
+X<sv_catpvf_mg_nocontext>
+
+=item sv_catpvf_nocontext
+X<sv_catpvf_nocontext>
+
+=item sv_compile_2op
+X<sv_compile_2op>
+
+=item sv_dump
+X<sv_dump>
+
+=item sv_dup
+X<sv_dup>
+
+=item sv_peek
+X<sv_peek>
+
+=item sv_pvn_nomg
+X<sv_pvn_nomg>
+
+=item sv_setpvf_mg_nocontext
+X<sv_setpvf_mg_nocontext>
+
+=item sv_setpvf_nocontext
+X<sv_setpvf_nocontext>
+
+=item sv_utf8_upgrade_flags_grow
+X<sv_utf8_upgrade_flags_grow>
+
+=item swash_fetch
+X<swash_fetch>
+
+=item swash_init
+X<swash_init>
+
+=item sys_init
+X<sys_init>
+
+=item sys_init3
+X<sys_init3>
+
+=item sys_intern_clear
+X<sys_intern_clear>
+
+=item sys_intern_dup
+X<sys_intern_dup>
+
+=item sys_intern_init
+X<sys_intern_init>
+
+=item sys_term
+X<sys_term>
+
+=item taint_env
+X<taint_env>
+
+=item taint_proper
+X<taint_proper>
+
+=item tmps_grow
+X<tmps_grow>
+
+=item to_uni_fold
+X<to_uni_fold>
+
+=item to_uni_lower
+X<to_uni_lower>
+
+=item to_uni_lower_lc
+X<to_uni_lower_lc>
+
+=item to_uni_title
+X<to_uni_title>
+
+=item to_uni_title_lc
+X<to_uni_title_lc>
+
+=item to_uni_upper
+X<to_uni_upper>
+
+=item to_uni_upper_lc
+X<to_uni_upper_lc>
+
+=item unlnk
+X<unlnk>
+
+=item unsharepvn
+X<unsharepvn>
+
+=item utf16_to_utf8
+X<utf16_to_utf8>
+
+=item utf16_to_utf8_reversed
+X<utf16_to_utf8_reversed>
+
+=item uvchr_to_utf8_flags
+X<uvchr_to_utf8_flags>
+
+=item uvuni_to_utf8
+X<uvuni_to_utf8>
+
+=item vcroak
+X<vcroak>
+
+=item vdeb
+X<vdeb>
+
+=item vform
+X<vform>
+
+=item vload_module
+X<vload_module>
+
+=item vmess
+X<vmess>
+
+=item vnewSVpvf
+X<vnewSVpvf>
+
+=item vwarn
+X<vwarn>
+
+=item vwarner
+X<vwarner>
+
+=item warn_nocontext
+X<warn_nocontext>
+
+=item warner
+X<warner>
+
+=item warner_nocontext
+X<warner_nocontext>
+
+=item whichsig
+X<whichsig>
+
+=back
+
+
+=head1 AUTHORS
+
+Until May 1997, this document was maintained by Jeff Okamoto
+<okamoto@corp.hp.com>. It is now maintained as part of Perl itself.
+
+With lots of help and suggestions from Dean Roehrich, Malcolm Beattie,
+Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil
+Bowers, Matthew Green, Tim Bunce, Spider Boardman, Ulrich Pfeifer,
+Stephen McCamant, and Gurusamy Sarathy.
+
+API Listing originally by Dean Roehrich <roehrich@cray.com>.
+
+Updated to be autogenerated from comments in the source by Benjamin Stuhl.
+
+=head1 SEE ALSO
+
+L<perlguts>, L<perlxs>, L<perlxstut>, L<perlintern>
+
+=cut
+
+ ex: set ro:
diff --git a/Master/tlpkg/tlperl/lib/pods/perlapio.pod b/Master/tlpkg/tlperl/lib/pods/perlapio.pod
new file mode 100644
index 00000000000..1c57f9a9a89
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlapio.pod
@@ -0,0 +1,526 @@
+=head1 NAME
+
+perlapio - perl's IO abstraction interface.
+
+=head1 SYNOPSIS
+
+ #define PERLIO_NOT_STDIO 0 /* For co-existence with stdio only */
+ #include <perlio.h> /* Usually via #include <perl.h> */
+
+ PerlIO *PerlIO_stdin(void);
+ PerlIO *PerlIO_stdout(void);
+ PerlIO *PerlIO_stderr(void);
+
+ PerlIO *PerlIO_open(const char *path,const char *mode);
+ PerlIO *PerlIO_fdopen(int fd, const char *mode);
+ PerlIO *PerlIO_reopen(const char *path, const char *mode, PerlIO *old); /* deprecated */
+ int PerlIO_close(PerlIO *f);
+
+ int PerlIO_stdoutf(const char *fmt,...)
+ int PerlIO_puts(PerlIO *f,const char *string);
+ int PerlIO_putc(PerlIO *f,int ch);
+ int PerlIO_write(PerlIO *f,const void *buf,size_t numbytes);
+ int PerlIO_printf(PerlIO *f, const char *fmt,...);
+ int PerlIO_vprintf(PerlIO *f, const char *fmt, va_list args);
+ int PerlIO_flush(PerlIO *f);
+
+ int PerlIO_eof(PerlIO *f);
+ int PerlIO_error(PerlIO *f);
+ void PerlIO_clearerr(PerlIO *f);
+
+ int PerlIO_getc(PerlIO *d);
+ int PerlIO_ungetc(PerlIO *f,int ch);
+ int PerlIO_read(PerlIO *f, void *buf, size_t numbytes);
+
+ int PerlIO_fileno(PerlIO *f);
+
+ void PerlIO_setlinebuf(PerlIO *f);
+
+ Off_t PerlIO_tell(PerlIO *f);
+ int PerlIO_seek(PerlIO *f, Off_t offset, int whence);
+ void PerlIO_rewind(PerlIO *f);
+
+ int PerlIO_getpos(PerlIO *f, SV *save); /* prototype changed */
+ int PerlIO_setpos(PerlIO *f, SV *saved); /* prototype changed */
+
+ int PerlIO_fast_gets(PerlIO *f);
+ int PerlIO_has_cntptr(PerlIO *f);
+ int PerlIO_get_cnt(PerlIO *f);
+ char *PerlIO_get_ptr(PerlIO *f);
+ void PerlIO_set_ptrcnt(PerlIO *f, char *ptr, int count);
+
+ int PerlIO_canset_cnt(PerlIO *f); /* deprecated */
+ void PerlIO_set_cnt(PerlIO *f, int count); /* deprecated */
+
+ int PerlIO_has_base(PerlIO *f);
+ char *PerlIO_get_base(PerlIO *f);
+ int PerlIO_get_bufsiz(PerlIO *f);
+
+ PerlIO *PerlIO_importFILE(FILE *stdio, const char *mode);
+ FILE *PerlIO_exportFILE(PerlIO *f, int flags);
+ FILE *PerlIO_findFILE(PerlIO *f);
+ void PerlIO_releaseFILE(PerlIO *f,FILE *stdio);
+
+ int PerlIO_apply_layers(PerlIO *f, const char *mode, const char *layers);
+ int PerlIO_binmode(PerlIO *f, int ptype, int imode, const char *layers);
+ void PerlIO_debug(const char *fmt,...)
+
+=head1 DESCRIPTION
+
+Perl's source code, and extensions that want maximum portability,
+should use the above functions instead of those defined in ANSI C's
+I<stdio.h>. The perl headers (in particular "perlio.h") will
+C<#define> them to the I/O mechanism selected at Configure time.
+
+The functions are modeled on those in I<stdio.h>, but parameter order
+has been "tidied up a little".
+
+C<PerlIO *> takes the place of FILE *. Like FILE * it should be
+treated as opaque (it is probably safe to assume it is a pointer to
+something).
+
+There are currently three implementations:
+
+=over 4
+
+=item 1. USE_STDIO
+
+All above are #define'd to stdio functions or are trivial wrapper
+functions which call stdio. In this case I<only> PerlIO * is a FILE *.
+This has been the default implementation since the abstraction was
+introduced in perl5.003_02.
+
+=item 2. USE_SFIO
+
+A "legacy" implementation in terms of the "sfio" library. Used for
+some specialist applications on Unix machines ("sfio" is not widely
+ported away from Unix). Most of above are #define'd to the sfio
+functions. PerlIO * is in this case Sfio_t *.
+
+=item 3. USE_PERLIO
+
+Introduced just after perl5.7.0, this is a re-implementation of the
+above abstraction which allows perl more control over how IO is done
+as it decouples IO from the way the operating system and C library
+choose to do things. For USE_PERLIO PerlIO * has an extra layer of
+indirection - it is a pointer-to-a-pointer. This allows the PerlIO *
+to remain with a known value while swapping the implementation around
+underneath I<at run time>. In this case all the above are true (but
+very simple) functions which call the underlying implementation.
+
+This is the only implementation for which C<PerlIO_apply_layers()>
+does anything "interesting".
+
+The USE_PERLIO implementation is described in L<perliol>.
+
+=back
+
+Because "perlio.h" is a thin layer (for efficiency) the semantics of
+these functions are somewhat dependent on the underlying implementation.
+Where these variations are understood they are noted below.
+
+Unless otherwise noted, functions return 0 on success, or a negative
+value (usually C<EOF> which is usually -1) and set C<errno> on error.
+
+=over 4
+
+=item B<PerlIO_stdin()>, B<PerlIO_stdout()>, B<PerlIO_stderr()>
+
+Use these rather than C<stdin>, C<stdout>, C<stderr>. They are written
+to look like "function calls" rather than variables because this makes
+it easier to I<make them> function calls if platform cannot export data
+to loaded modules, or if (say) different "threads" might have different
+values.
+
+=item B<PerlIO_open(path, mode)>, B<PerlIO_fdopen(fd,mode)>
+
+These correspond to fopen()/fdopen() and the arguments are the same.
+Return C<NULL> and set C<errno> if there is an error. There may be an
+implementation limit on the number of open handles, which may be lower
+than the limit on the number of open files - C<errno> may not be set
+when C<NULL> is returned if this limit is exceeded.
+
+=item B<PerlIO_reopen(path,mode,f)>
+
+While this currently exists in all three implementations perl itself
+does not use it. I<As perl does not use it, it is not well tested.>
+
+Perl prefers to C<dup> the new low-level descriptor to the descriptor
+used by the existing PerlIO. This may become the behaviour of this
+function in the future.
+
+=item B<PerlIO_printf(f,fmt,...)>, B<PerlIO_vprintf(f,fmt,a)>
+
+These are fprintf()/vfprintf() equivalents.
+
+=item B<PerlIO_stdoutf(fmt,...)>
+
+This is printf() equivalent. printf is #defined to this function,
+so it is (currently) legal to use C<printf(fmt,...)> in perl sources.
+
+=item B<PerlIO_read(f,buf,count)>, B<PerlIO_write(f,buf,count)>
+
+These correspond functionally to fread() and fwrite() but the
+arguments and return values are different. The PerlIO_read() and
+PerlIO_write() signatures have been modeled on the more sane low level
+read() and write() functions instead: The "file" argument is passed
+first, there is only one "count", and the return value can distinguish
+between error and C<EOF>.
+
+Returns a byte count if successful (which may be zero or
+positive), returns negative value and sets C<errno> on error.
+Depending on implementation C<errno> may be C<EINTR> if operation was
+interrupted by a signal.
+
+=item B<PerlIO_close(f)>
+
+Depending on implementation C<errno> may be C<EINTR> if operation was
+interrupted by a signal.
+
+=item B<PerlIO_puts(f,s)>, B<PerlIO_putc(f,c)>
+
+These correspond to fputs() and fputc().
+Note that arguments have been revised to have "file" first.
+
+=item B<PerlIO_ungetc(f,c)>
+
+This corresponds to ungetc(). Note that arguments have been revised
+to have "file" first. Arranges that next read operation will return
+the byte B<c>. Despite the implied "character" in the name only
+values in the range 0..0xFF are defined. Returns the byte B<c> on
+success or -1 (C<EOF>) on error. The number of bytes that can be
+"pushed back" may vary, only 1 character is certain, and then only if
+it is the last character that was read from the handle.
+
+=item B<PerlIO_getc(f)>
+
+This corresponds to getc().
+Despite the c in the name only byte range 0..0xFF is supported.
+Returns the character read or -1 (C<EOF>) on error.
+
+=item B<PerlIO_eof(f)>
+
+This corresponds to feof(). Returns a true/false indication of
+whether the handle is at end of file. For terminal devices this may
+or may not be "sticky" depending on the implementation. The flag is
+cleared by PerlIO_seek(), or PerlIO_rewind().
+
+=item B<PerlIO_error(f)>
+
+This corresponds to ferror(). Returns a true/false indication of
+whether there has been an IO error on the handle.
+
+=item B<PerlIO_fileno(f)>
+
+This corresponds to fileno(), note that on some platforms, the meaning
+of "fileno" may not match Unix. Returns -1 if the handle has no open
+descriptor associated with it.
+
+=item B<PerlIO_clearerr(f)>
+
+This corresponds to clearerr(), i.e., clears 'error' and (usually)
+'eof' flags for the "stream". Does not return a value.
+
+=item B<PerlIO_flush(f)>
+
+This corresponds to fflush(). Sends any buffered write data to the
+underlying file. If called with C<NULL> this may flush all open
+streams (or core dump with some USE_STDIO implementations). Calling
+on a handle open for read only, or on which last operation was a read
+of some kind may lead to undefined behaviour on some USE_STDIO
+implementations. The USE_PERLIO (layers) implementation tries to
+behave better: it flushes all open streams when passed C<NULL>, and
+attempts to retain data on read streams either in the buffer or by
+seeking the handle to the current logical position.
+
+=item B<PerlIO_seek(f,offset,whence)>
+
+This corresponds to fseek(). Sends buffered write data to the
+underlying file, or discards any buffered read data, then positions
+the file descriptor as specified by B<offset> and B<whence> (sic).
+This is the correct thing to do when switching between read and write
+on the same handle (see issues with PerlIO_flush() above). Offset is
+of type C<Off_t> which is a perl Configure value which may not be same
+as stdio's C<off_t>.
+
+=item B<PerlIO_tell(f)>
+
+This corresponds to ftell(). Returns the current file position, or
+(Off_t) -1 on error. May just return value system "knows" without
+making a system call or checking the underlying file descriptor (so
+use on shared file descriptors is not safe without a
+PerlIO_seek()). Return value is of type C<Off_t> which is a perl
+Configure value which may not be same as stdio's C<off_t>.
+
+=item B<PerlIO_getpos(f,p)>, B<PerlIO_setpos(f,p)>
+
+These correspond (loosely) to fgetpos() and fsetpos(). Rather than
+stdio's Fpos_t they expect a "Perl Scalar Value" to be passed. What is
+stored there should be considered opaque. The layout of the data may
+vary from handle to handle. When not using stdio or if platform does
+not have the stdio calls then they are implemented in terms of
+PerlIO_tell() and PerlIO_seek().
+
+=item B<PerlIO_rewind(f)>
+
+This corresponds to rewind(). It is usually defined as being
+
+ PerlIO_seek(f,(Off_t)0L, SEEK_SET);
+ PerlIO_clearerr(f);
+
+=item B<PerlIO_tmpfile()>
+
+This corresponds to tmpfile(), i.e., returns an anonymous PerlIO or
+NULL on error. The system will attempt to automatically delete the
+file when closed. On Unix the file is usually C<unlink>-ed just after
+it is created so it does not matter how it gets closed. On other
+systems the file may only be deleted if closed via PerlIO_close()
+and/or the program exits via C<exit>. Depending on the implementation
+there may be "race conditions" which allow other processes access to
+the file, though in general it will be safer in this regard than
+ad. hoc. schemes.
+
+=item B<PerlIO_setlinebuf(f)>
+
+This corresponds to setlinebuf(). Does not return a value. What
+constitutes a "line" is implementation dependent but usually means
+that writing "\n" flushes the buffer. What happens with things like
+"this\nthat" is uncertain. (Perl core uses it I<only> when "dumping";
+it has nothing to do with $| auto-flush.)
+
+=back
+
+=head2 Co-existence with stdio
+
+There is outline support for co-existence of PerlIO with stdio.
+Obviously if PerlIO is implemented in terms of stdio there is no
+problem. However in other cases then mechanisms must exist to create a
+FILE * which can be passed to library code which is going to use stdio
+calls.
+
+The first step is to add this line:
+
+ #define PERLIO_NOT_STDIO 0
+
+I<before> including any perl header files. (This will probably become
+the default at some point). That prevents "perlio.h" from attempting
+to #define stdio functions onto PerlIO functions.
+
+XS code is probably better using "typemap" if it expects FILE *
+arguments. The standard typemap will be adjusted to comprehend any
+changes in this area.
+
+=over 4
+
+=item B<PerlIO_importFILE(f,mode)>
+
+Used to get a PerlIO * from a FILE *.
+
+The mode argument should be a string as would be passed to
+fopen/PerlIO_open. If it is NULL then - for legacy support - the code
+will (depending upon the platform and the implementation) either
+attempt to empirically determine the mode in which I<f> is open, or
+use "r+" to indicate a read/write stream.
+
+Once called the FILE * should I<ONLY> be closed by calling
+C<PerlIO_close()> on the returned PerlIO *.
+
+The PerlIO is set to textmode. Use PerlIO_binmode if this is
+not the desired mode.
+
+This is B<not> the reverse of PerlIO_exportFILE().
+
+=item B<PerlIO_exportFILE(f,mode)>
+
+Given a PerlIO * create a 'native' FILE * suitable for passing to code
+expecting to be compiled and linked with ANSI C I<stdio.h>. The mode
+argument should be a string as would be passed to fopen/PerlIO_open.
+If it is NULL then - for legacy support - the FILE * is opened in same
+mode as the PerlIO *.
+
+The fact that such a FILE * has been 'exported' is recorded, (normally
+by pushing a new :stdio "layer" onto the PerlIO *), which may affect
+future PerlIO operations on the original PerlIO *. You should not
+call C<fclose()> on the file unless you call C<PerlIO_releaseFILE()>
+to disassociate it from the PerlIO *. (Do not use PerlIO_importFILE()
+for doing the disassociation.)
+
+Calling this function repeatedly will create a FILE * on each call
+(and will push an :stdio layer each time as well).
+
+=item B<PerlIO_releaseFILE(p,f)>
+
+Calling PerlIO_releaseFILE informs PerlIO that all use of FILE * is
+complete. It is removed from the list of 'exported' FILE *s, and the
+associated PerlIO * should revert to its original behaviour.
+
+Use this to disassociate a file from a PerlIO * that was associated
+using PerlIO_exportFILE().
+
+=item B<PerlIO_findFILE(f)>
+
+Returns a native FILE * used by a stdio layer. If there is none, it
+will create one with PerlIO_exportFILE. In either case the FILE *
+should be considered as belonging to PerlIO subsystem and should
+only be closed by calling C<PerlIO_close()>.
+
+
+=back
+
+=head2 "Fast gets" Functions
+
+In addition to standard-like API defined so far above there is an
+"implementation" interface which allows perl to get at internals of
+PerlIO. The following calls correspond to the various FILE_xxx macros
+determined by Configure - or their equivalent in other
+implementations. This section is really of interest to only those
+concerned with detailed perl-core behaviour, implementing a PerlIO
+mapping or writing code which can make use of the "read ahead" that
+has been done by the IO system in the same way perl does. Note that
+any code that uses these interfaces must be prepared to do things the
+traditional way if a handle does not support them.
+
+=over 4
+
+=item B<PerlIO_fast_gets(f)>
+
+Returns true if implementation has all the interfaces required to
+allow perl's C<sv_gets> to "bypass" normal IO mechanism. This can
+vary from handle to handle.
+
+ PerlIO_fast_gets(f) = PerlIO_has_cntptr(f) && \
+ PerlIO_canset_cnt(f) && \
+ `Can set pointer into buffer'
+
+
+=item B<PerlIO_has_cntptr(f)>
+
+Implementation can return pointer to current position in the "buffer"
+and a count of bytes available in the buffer. Do not use this - use
+PerlIO_fast_gets.
+
+=item B<PerlIO_get_cnt(f)>
+
+Return count of readable bytes in the buffer. Zero or negative return
+means no more bytes available.
+
+=item B<PerlIO_get_ptr(f)>
+
+Return pointer to next readable byte in buffer, accessing via the
+pointer (dereferencing) is only safe if PerlIO_get_cnt() has returned
+a positive value. Only positive offsets up to value returned by
+PerlIO_get_cnt() are allowed.
+
+=item B<PerlIO_set_ptrcnt(f,p,c)>
+
+Set pointer into buffer, and a count of bytes still in the
+buffer. Should be used only to set pointer to within range implied by
+previous calls to C<PerlIO_get_ptr> and C<PerlIO_get_cnt>. The two
+values I<must> be consistent with each other (implementation may only
+use one or the other or may require both).
+
+=item B<PerlIO_canset_cnt(f)>
+
+Implementation can adjust its idea of number of bytes in the buffer.
+Do not use this - use PerlIO_fast_gets.
+
+=item B<PerlIO_set_cnt(f,c)>
+
+Obscure - set count of bytes in the buffer. Deprecated. Only usable
+if PerlIO_canset_cnt() returns true. Currently used in only doio.c to
+force count less than -1 to -1. Perhaps should be PerlIO_set_empty or
+similar. This call may actually do nothing if "count" is deduced from
+pointer and a "limit". Do not use this - use PerlIO_set_ptrcnt().
+
+=item B<PerlIO_has_base(f)>
+
+Returns true if implementation has a buffer, and can return pointer
+to whole buffer and its size. Used by perl for B<-T> / B<-B> tests.
+Other uses would be very obscure...
+
+=item B<PerlIO_get_base(f)>
+
+Return I<start> of buffer. Access only positive offsets in the buffer
+up to the value returned by PerlIO_get_bufsiz().
+
+=item B<PerlIO_get_bufsiz(f)>
+
+Return the I<total number of bytes> in the buffer, this is neither the
+number that can be read, nor the amount of memory allocated to the
+buffer. Rather it is what the operating system and/or implementation
+happened to C<read()> (or whatever) last time IO was requested.
+
+=back
+
+=head2 Other Functions
+
+=over 4
+
+=item PerlIO_apply_layers(f,mode,layers)
+
+The new interface to the USE_PERLIO implementation. The layers ":crlf"
+and ":raw" are only ones allowed for other implementations and those
+are silently ignored. (As of perl5.8 ":raw" is deprecated.) Use
+PerlIO_binmode() below for the portable case.
+
+=item PerlIO_binmode(f,ptype,imode,layers)
+
+The hook used by perl's C<binmode> operator.
+B<ptype> is perl's character for the kind of IO:
+
+=over 8
+
+=item 'E<lt>' read
+
+=item 'E<gt>' write
+
+=item '+' read/write
+
+=back
+
+B<imode> is C<O_BINARY> or C<O_TEXT>.
+
+B<layers> is a string of layers to apply, only ":crlf" makes sense in
+the non USE_PERLIO case. (As of perl5.8 ":raw" is deprecated in favour
+of passing NULL.)
+
+Portable cases are:
+
+ PerlIO_binmode(f,ptype,O_BINARY,NULL);
+and
+ PerlIO_binmode(f,ptype,O_TEXT,":crlf");
+
+On Unix these calls probably have no effect whatsoever. Elsewhere
+they alter "\n" to CR,LF translation and possibly cause a special text
+"end of file" indicator to be written or honoured on read. The effect
+of making the call after doing any IO to the handle depends on the
+implementation. (It may be ignored, affect any data which is already
+buffered as well, or only apply to subsequent data.)
+
+=item PerlIO_debug(fmt,...)
+
+PerlIO_debug is a printf()-like function which can be used for
+debugging. No return value. Its main use is inside PerlIO where using
+real printf, warn() etc. would recursively call PerlIO and be a
+problem.
+
+PerlIO_debug writes to the file named by $ENV{'PERLIO_DEBUG'} typical
+use might be
+
+ Bourne shells (sh, ksh, bash, zsh, ash, ...):
+ PERLIO_DEBUG=/dev/tty ./perl somescript some args
+
+ Csh/Tcsh:
+ setenv PERLIO_DEBUG /dev/tty
+ ./perl somescript some args
+
+ If you have the "env" utility:
+ env PERLIO_DEBUG=/dev/tty ./perl somescript some args
+
+ Win32:
+ set PERLIO_DEBUG=CON
+ perl somescript some args
+
+If $ENV{'PERLIO_DEBUG'} is not set PerlIO_debug() is a no-op.
+
+=back
diff --git a/Master/tlpkg/tlperl/lib/pods/perlapollo.pod b/Master/tlpkg/tlperl/lib/pods/perlapollo.pod
new file mode 100644
index 00000000000..cc12e6a5cd6
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlapollo.pod
@@ -0,0 +1,23 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.apollo - Perl version 5 on Apollo DomainOS
+
+=head1 DESCRIPTION
+
+The following tests are known to fail as of Perl 5.005_03:
+
+comp/decl..........FAILED at test 0
+op/write...........FAILED at test 0
+lib/filefind.......FAILED at test 2
+lib/io_udp.........FAILED at test 2
+lib/findbin........stat(/ressel/ABT/USER/vta/jk/proj.local/perl/perl5.005_03-MAINT_TRIAL_5/t/lib/): No such file or directory at ../lib/FindBin.pm line 162
+stat(/ressel/ABT/USER/vta/jk/proj.local/perl/perl5.005_03-MAINT_TRIAL_5/t/lib/): No such file or directory at ../lib/FindBin.pm line 163
+FAILED at test 1
+
+=head1 AUTHOR
+
+Johann Klasek <jk@auto.tuwien.ac.at>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlartistic.pod b/Master/tlpkg/tlperl/lib/pods/perlartistic.pod
new file mode 100644
index 00000000000..63813ff4fb9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlartistic.pod
@@ -0,0 +1,224 @@
+
+=head1 NAME
+
+perlartistic - the Perl Artistic License
+
+=head1 SYNOPSIS
+
+ You can refer to this document in Pod via "L<perlartistic>"
+ Or you can see this document by entering "perldoc perlartistic"
+
+=head1 DESCRIPTION
+
+Perl is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+ a) the GNU General Public License as published by the Free
+ Software Foundation; either version 1, or (at your option) any
+ later version, or
+
+ b) the "Artistic License" which comes with this Kit.
+
+This is B<"The Artistic License">.
+It's here so that modules, programs, etc., that want to declare
+this as their distribution license can link to it.
+
+For the GNU General Public License, see L<perlgpl>.
+
+=head1 The "Artistic License"
+
+=head2 Preamble
+
+The intent of this document is to state the conditions under which a
+Package may be copied, such that the Copyright Holder maintains some
+semblance of artistic control over the development of the package,
+while giving the users of the package the right to use and distribute
+the Package in a more-or-less customary fashion, plus the right to make
+reasonable modifications.
+
+=head2 Definitions
+
+=over
+
+=item "Package"
+
+refers to the collection of files distributed by the
+Copyright Holder, and derivatives of that collection of files created
+through textual modification.
+
+=item "Standard Version"
+
+refers to such a Package if it has not been
+modified, or has been modified in accordance with the wishes of the
+Copyright Holder as specified below.
+
+=item "Copyright Holder"
+
+is whoever is named in the copyright or
+copyrights for the package.
+
+=item "You"
+
+is you, if you're thinking about copying or distributing this Package.
+
+=item "Reasonable copying fee"
+
+is whatever you can justify on the basis
+of media cost, duplication charges, time of people involved, and so on.
+(You will not be required to justify it to the Copyright Holder, but
+only to the computing community at large as a market that must bear the
+fee.)
+
+=item "Freely Available"
+
+means that no fee is charged for the item
+itself, though there may be fees involved in handling the item. It also
+means that recipients of the item may redistribute it under the same
+conditions they received it.
+
+=back
+
+=head2 Conditions
+
+=over
+
+=item 1.
+
+You may make and give away verbatim copies of the source form of the
+Standard Version of this Package without restriction, provided that you
+duplicate all of the original copyright notices and associated disclaimers.
+
+=item 2.
+
+You may apply bug fixes, portability fixes and other modifications
+derived from the Public Domain or from the Copyright Holder. A Package
+modified in such a way shall still be considered the Standard Version.
+
+=item 3.
+
+You may otherwise modify your copy of this Package in any way, provided
+that you insert a prominent notice in each changed file stating how and
+when you changed that file, and provided that you do at least ONE of the
+following:
+
+=over
+
+=item a)
+
+place your modifications in the Public Domain or otherwise make them
+Freely Available, such as by posting said modifications to Usenet or an
+equivalent medium, or placing the modifications on a major archive site
+such as uunet.uu.net, or by allowing the Copyright Holder to include
+your modifications in the Standard Version of the Package.
+
+=item b)
+
+use the modified Package only within your corporation or organization.
+
+=item c)
+
+rename any non-standard executables so the names do not conflict with
+standard executables, which must also be provided, and provide a
+separate manual page for each non-standard executable that clearly
+documents how it differs from the Standard Version.
+
+=item d)
+
+make other distribution arrangements with the Copyright Holder.
+
+=back
+
+=item 4.
+
+You may distribute the programs of this Package in object code or
+executable form, provided that you do at least ONE of the following:
+
+=over
+
+=item a)
+
+distribute a Standard Version of the executables and library files,
+together with instructions (in the manual page or equivalent) on where
+to get the Standard Version.
+
+=item b)
+
+accompany the distribution with the machine-readable source of the
+Package with your modifications.
+
+=item c)
+
+give non-standard executables non-standard names, and clearly
+document the differences in manual pages (or equivalent), together with
+instructions on where to get the Standard Version.
+
+=item d)
+
+make other distribution arrangements with the Copyright Holder.
+
+=back
+
+=item 5.
+
+You may charge a reasonable copying fee for any distribution of this
+Package. You may charge any fee you choose for support of this
+Package. You may not charge a fee for this Package itself. However,
+you may distribute this Package in aggregate with other (possibly
+commercial) programs as part of a larger (possibly commercial) software
+distribution provided that you do not advertise this Package as a
+product of your own. You may embed this Package's interpreter within
+an executable of yours (by linking); this shall be construed as a mere
+form of aggregation, provided that the complete Standard Version of the
+interpreter is so embedded.
+
+=item 6.
+
+The scripts and library files supplied as input to or produced as
+output from the programs of this Package do not automatically fall
+under the copyright of this Package, but belong to whoever generated
+them, and may be sold commercially, and may be aggregated with this
+Package. If such scripts or library files are aggregated with this
+Package via the so-called "undump" or "unexec" methods of producing a
+binary executable image, then distribution of such an image shall
+neither be construed as a distribution of this Package nor shall it
+fall under the restrictions of Paragraphs 3 and 4, provided that you do
+not represent such an executable image as a Standard Version of this
+Package.
+
+=item 7.
+
+C subroutines (or comparably compiled subroutines in other
+languages) supplied by you and linked into this Package in order to
+emulate subroutines and variables of the language defined by this
+Package shall not be considered part of this Package, but are the
+equivalent of input as in Paragraph 6, provided these subroutines do
+not change the language in any way that would cause it to fail the
+regression tests for the language.
+
+=item 8.
+
+Aggregation of this Package with a commercial distribution is always
+permitted provided that the use of this Package is embedded; that is,
+when no overt attempt is made to make this Package's interfaces visible
+to the end user of the commercial distribution. Such use shall not be
+construed as a distribution of this Package.
+
+=item 9.
+
+The name of the Copyright Holder may not be used to endorse or promote
+products derived from this software without specific prior written permission.
+
+
+=item 10.
+
+THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+
+=back
+
+The End
+
+=cut
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlbeos.pod b/Master/tlpkg/tlperl/lib/pods/perlbeos.pod
new file mode 100644
index 00000000000..0a01f50b9ee
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlbeos.pod
@@ -0,0 +1,109 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.beos - Perl version 5.8+ on BeOS
+
+=head1 DESCRIPTION
+
+This file contains instructions how to build Perl under BeOS and lists
+known problems.
+
+=head1 BUILD AND INSTALL
+
+=head2 Requirements
+
+I have built and tested Perl 5.8.6 and 5.9.1 under BeOS R5 x86 net server.
+I can't say anything with regard to PPC. Since Perl 5.8.0 had been released
+for BeOS BONE, I suspect, there is a good chance, that it still compiles on
+a BONE system. The only change I've made, that affects BONE systems is the
+recognition of whether it is a BONE system or not in C<hints/beos.sh>. Now
+network socket support should remain enabled on BONE systems. This might
+as well break the build, though.
+
+As more recent versions of autoconf require flock() support, I wrote a flock()
+emulation (flock_server) and released it on BeBits:
+
+ http://www.bebits.com/app/4030
+
+If you want to build a Perl with flock() support, you have to install this
+package first.
+
+=head2 Configure
+
+With flock() support:
+
+ CFLAGS=-I/path/to/flock/server/headers ./configure.gnu \
+ --prefix=/boot/home/config
+
+Replace C</path/to/flock/server/headers> with the path to the directory
+containing the C<flock.h> header.
+
+Without flock() support:
+
+ ./configure.gnu --prefix=/boot/home/config
+
+=head2 Build
+
+With flock() support:
+
+ make LDLOADLIBS="-lnet -lflock"
+
+Without flock() support:
+
+ make LDLOADLIBS="-lnet"
+
+C<-lnet> is needed on net server systems only and if the compiler doesn't
+add it automatically (Be's R5 gcc does, Oliver Tappe's gcc 2.95.3 does not).
+
+=head2 Install
+
+Install all perl files:
+
+ make install
+
+Create a symlink for libperl:
+
+ cd ~/config/lib; ln -s perl5/5.8.6/BePC-beos/CORE/libperl.so .
+
+Replace C<5.8.6> with your respective version of Perl.
+
+=head1 KNOWN PROBLEMS
+
+=over 4
+
+=item *
+
+Network socket support is disabled for BeOS R5 net server. I didn't dare yet
+to try enabling it and see what problems occur.
+
+=item *
+
+The LFS (large file support) tests (C<t/op/lfs> and C<xt/Fcntl/t/syslfs>) are
+disabled as seeking beyond 2 GB is broken according to jhi@iki.fi who was the
+last one checking the BeOS port and updating this file before me. Haven't
+checked this myself.
+
+=item *
+
+The C<t/io/fflush> test fails at #6. As far as I can tell, this is caused by
+a bug in the BeOS pipes implementation that occurs when starting other child
+processes. In the particular test case a C<system("perl -e 0")> flushes the
+stdout pipe of another child process.
+
+=item *
+
+The C<ext/POSIX/t/waitpid> test fails at #1. After all child processes are
+gone BeOS' waitpid(-1,...) returns 0 instead of -1 (as it should). No idea
+how to fix this.
+
+=back
+
+=head1 CONTACT
+
+For BeOS specifics problems feel free to mail to:
+Ingo Weinhold <bonefish@cs.tu-berlin.de>
+
+Last update: 2004-12-16
diff --git a/Master/tlpkg/tlperl/lib/pods/perlbook.pod b/Master/tlpkg/tlperl/lib/pods/perlbook.pod
new file mode 100644
index 00000000000..b48379f5644
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlbook.pod
@@ -0,0 +1,17 @@
+=head1 NAME
+
+perlbook - Perl book information
+
+=head1 DESCRIPTION
+
+The Camel Book, officially known as I<Programming Perl, Third Edition>,
+by Larry Wall et al, is the definitive reference work covering nearly
+all of Perl. You can order it and other Perl books from O'Reilly &
+Associates, 1-800-998-9938. Local/overseas is +1 707 829 0515. If you
+can locate an O'Reilly order form, you can also fax to +1 707 829 0104.
+If you're web-connected, you can even mosey on over to
+L<http://www.oreilly.com/> for an online order form.
+
+Other Perl books from various publishers and authors
+can be found listed in L<perlfaq2> or on the web at
+L<http://books.perl.org/>.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlboot.pod b/Master/tlpkg/tlperl/lib/pods/perlboot.pod
new file mode 100644
index 00000000000..a6b256a0fcc
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlboot.pod
@@ -0,0 +1,884 @@
+=head1 NAME
+
+perlboot - Beginner's Object-Oriented Tutorial
+
+=head1 DESCRIPTION
+
+If you're not familiar with objects from other languages, some of the
+other Perl object documentation may be a little daunting, such as
+L<perlobj>, a basic reference in using objects, and L<perltoot>, which
+introduces readers to the peculiarities of Perl's object system in a
+tutorial way.
+
+So, let's take a different approach, presuming no prior object
+experience. It helps if you know about subroutines (L<perlsub>),
+references (L<perlref> et. seq.), and packages (L<perlmod>), so become
+familiar with those first if you haven't already.
+
+=head2 If we could talk to the animals...
+
+Let's let the animals talk for a moment:
+
+ sub Cow::speak {
+ print "a Cow goes moooo!\n";
+ }
+ sub Horse::speak {
+ print "a Horse goes neigh!\n";
+ }
+ sub Sheep::speak {
+ print "a Sheep goes baaaah!\n";
+ }
+
+ Cow::speak;
+ Horse::speak;
+ Sheep::speak;
+
+This results in:
+
+ a Cow goes moooo!
+ a Horse goes neigh!
+ a Sheep goes baaaah!
+
+Nothing spectacular here. Simple subroutines, albeit from separate
+packages, and called using the full package name. So let's create
+an entire pasture:
+
+ # Cow::speak, Horse::speak, Sheep::speak as before
+ @pasture = qw(Cow Cow Horse Sheep Sheep);
+ foreach $animal (@pasture) {
+ &{$animal."::speak"};
+ }
+
+This results in:
+
+ a Cow goes moooo!
+ a Cow goes moooo!
+ a Horse goes neigh!
+ a Sheep goes baaaah!
+ a Sheep goes baaaah!
+
+Wow. That symbolic coderef de-referencing there is pretty nasty.
+We're counting on C<no strict refs> mode, certainly not recommended
+for larger programs. And why was that necessary? Because the name of
+the package seems to be inseparable from the name of the subroutine we
+want to invoke within that package.
+
+Or is it?
+
+=head2 Introducing the method invocation arrow
+
+For now, let's say that C<< Class->method >> invokes subroutine
+C<method> in package C<Class>. (Here, "Class" is used in its
+"category" meaning, not its "scholastic" meaning.) That's not
+completely accurate, but we'll do this one step at a time. Now let's
+use it like so:
+
+ # Cow::speak, Horse::speak, Sheep::speak as before
+ Cow->speak;
+ Horse->speak;
+ Sheep->speak;
+
+And once again, this results in:
+
+ a Cow goes moooo!
+ a Horse goes neigh!
+ a Sheep goes baaaah!
+
+That's not fun yet. Same number of characters, all constant, no
+variables. But yet, the parts are separable now. Watch:
+
+ $a = "Cow";
+ $a->speak; # invokes Cow->speak
+
+Ahh! Now that the package name has been parted from the subroutine
+name, we can use a variable package name. And this time, we've got
+something that works even when C<use strict refs> is enabled.
+
+=head2 Invoking a barnyard
+
+Let's take that new arrow invocation and put it back in the barnyard
+example:
+
+ sub Cow::speak {
+ print "a Cow goes moooo!\n";
+ }
+ sub Horse::speak {
+ print "a Horse goes neigh!\n";
+ }
+ sub Sheep::speak {
+ print "a Sheep goes baaaah!\n";
+ }
+
+ @pasture = qw(Cow Cow Horse Sheep Sheep);
+ foreach $animal (@pasture) {
+ $animal->speak;
+ }
+
+There! Now we have the animals all talking, and safely at that,
+without the use of symbolic coderefs.
+
+But look at all that common code. Each of the C<speak> routines has a
+similar structure: a C<print> operator and a string that contains
+common text, except for two of the words. It'd be nice if we could
+factor out the commonality, in case we decide later to change it all
+to C<says> instead of C<goes>.
+
+And we actually have a way of doing that without much fuss, but we
+have to hear a bit more about what the method invocation arrow is
+actually doing for us.
+
+=head2 The extra parameter of method invocation
+
+The invocation of:
+
+ Class->method(@args)
+
+attempts to invoke subroutine C<Class::method> as:
+
+ Class::method("Class", @args);
+
+(If the subroutine can't be found, "inheritance" kicks in, but we'll
+get to that later.) This means that we get the class name as the
+first parameter (the only parameter, if no arguments are given). So
+we can rewrite the C<Sheep> speaking subroutine as:
+
+ sub Sheep::speak {
+ my $class = shift;
+ print "a $class goes baaaah!\n";
+ }
+
+And the other two animals come out similarly:
+
+ sub Cow::speak {
+ my $class = shift;
+ print "a $class goes moooo!\n";
+ }
+ sub Horse::speak {
+ my $class = shift;
+ print "a $class goes neigh!\n";
+ }
+
+In each case, C<$class> will get the value appropriate for that
+subroutine. But once again, we have a lot of similar structure. Can
+we factor that out even further? Yes, by calling another method in
+the same class.
+
+=head2 Calling a second method to simplify things
+
+Let's call out from C<speak> to a helper method called C<sound>.
+This method provides the constant text for the sound itself.
+
+ { package Cow;
+ sub sound { "moooo" }
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ }
+ }
+
+Now, when we call C<< Cow->speak >>, we get a C<$class> of C<Cow> in
+C<speak>. This in turn selects the C<< Cow->sound >> method, which
+returns C<moooo>. But how different would this be for the C<Horse>?
+
+ { package Horse;
+ sub sound { "neigh" }
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ }
+ }
+
+Only the name of the package and the specific sound change. So can we
+somehow share the definition for C<speak> between the Cow and the
+Horse? Yes, with inheritance!
+
+=head2 Inheriting the windpipes
+
+We'll define a common subroutine package called C<Animal>, with the
+definition for C<speak>:
+
+ { package Animal;
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ }
+ }
+
+Then, for each animal, we say it "inherits" from C<Animal>, along
+with the animal-specific sound:
+
+ { package Cow;
+ @ISA = qw(Animal);
+ sub sound { "moooo" }
+ }
+
+Note the added C<@ISA> array (pronounced "is a"). We'll get to that in a minute.
+
+But what happens when we invoke C<< Cow->speak >> now?
+
+First, Perl constructs the argument list. In this case, it's just
+C<Cow>. Then Perl looks for C<Cow::speak>. But that's not there, so
+Perl checks for the inheritance array C<@Cow::ISA>. It's there,
+and contains the single name C<Animal>.
+
+Perl next checks for C<speak> inside C<Animal> instead, as in
+C<Animal::speak>. And that's found, so Perl invokes that subroutine
+with the already frozen argument list.
+
+Inside the C<Animal::speak> subroutine, C<$class> becomes C<Cow> (the
+first argument). So when we get to the step of invoking
+C<< $class->sound >>, it'll be looking for C<< Cow->sound >>, which
+gets it on the first try without looking at C<@ISA>. Success!
+
+=head2 A few notes about @ISA
+
+This magical C<@ISA> variable has declared that C<Cow> "is a" C<Animal>.
+Note that it's an array, not a simple single value, because on rare
+occasions, it makes sense to have more than one parent class searched
+for the missing methods.
+
+If C<Animal> also had an C<@ISA>, then we'd check there too. The
+search is recursive, depth-first, left-to-right in each C<@ISA> by
+default (see L<mro> for alternatives). Typically, each C<@ISA> has
+only one element (multiple elements means multiple inheritance and
+multiple headaches), so we get a nice tree of inheritance.
+
+When we turn on C<use strict>, we'll get complaints on C<@ISA>, since
+it's not a variable containing an explicit package name, nor is it a
+lexical ("my") variable. We can't make it a lexical variable though
+(it has to belong to the package to be found by the inheritance mechanism),
+so there's a couple of straightforward ways to handle that.
+
+The easiest is to just spell the package name out:
+
+ @Cow::ISA = qw(Animal);
+
+Or declare it as package global variable:
+
+ package Cow;
+ our @ISA = qw(Animal);
+
+Or allow it as an implicitly named package variable:
+
+ package Cow;
+ use vars qw(@ISA);
+ @ISA = qw(Animal);
+
+If the C<Animal> class comes from another (object-oriented) module, then
+just employ C<use base> to specify that C<Animal> should serve as the basis
+for the C<Cow> class:
+
+ package Cow;
+ use base qw(Animal);
+
+Now that's pretty darn simple!
+
+=head2 Overriding the methods
+
+Let's add a mouse, which can barely be heard:
+
+ # Animal package from before
+ { package Mouse;
+ @ISA = qw(Animal);
+ sub sound { "squeak" }
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ print "[but you can barely hear it!]\n";
+ }
+ }
+
+ Mouse->speak;
+
+which results in:
+
+ a Mouse goes squeak!
+ [but you can barely hear it!]
+
+Here, C<Mouse> has its own speaking routine, so C<< Mouse->speak >>
+doesn't immediately invoke C<< Animal->speak >>. This is known as
+"overriding". In fact, we don't even need to say that a C<Mouse> is
+an C<Animal> at all, because all of the methods needed for C<speak> are
+completely defined for C<Mouse>; this is known as "duck typing":
+"If it walks like a duck and quacks like a duck, I would call it a duck"
+(James Whitcomb). However, it would probably be beneficial to allow a
+closer examination to conclude that a C<Mouse> is indeed an C<Animal>,
+so it is actually better to define C<Mouse> with C<Animal> as its base
+(that is, it is better to "derive C<Mouse> from C<Animal>").
+
+Moreover, this duplication of code could become a maintenance headache
+(though code-reuse is not actually a good reason for inheritance; good
+design practices dictate that a derived class should be usable wherever
+its base class is usable, which might not be the outcome if code-reuse
+is the sole criterion for inheritance. Just remember that a C<Mouse>
+should always act like an C<Animal>).
+
+So, let's make C<Mouse> an C<Animal>!
+
+The obvious solution is to invoke C<Animal::speak> directly:
+
+ # Animal package from before
+ { package Mouse;
+ @ISA = qw(Animal);
+ sub sound { "squeak" }
+ sub speak {
+ my $class = shift;
+ Animal::speak($class);
+ print "[but you can barely hear it!]\n";
+ }
+ }
+
+Note that we're using C<Animal::speak>. If we were to invoke
+C<< Animal->speak >> instead, the first parameter to C<Animal::speak>
+would automatically be C<"Animal"> rather than C<"Mouse">, so that
+the call to C<< $class->sound >> in C<Animal::speak> would become
+C<< Animal->sound >> rather than C<< Mouse->sound >>.
+
+Also, without the method arrow C<< -> >>, it becomes necessary to specify
+the first parameter to C<Animal::speak> ourselves, which is why C<$class>
+is explicitly passed: C<Animal::speak($class)>.
+
+However, invoking C<Animal::speak> directly is a mess: Firstly, it assumes
+that the C<speak> method is a member of the C<Animal> class; what if C<Animal>
+actually inherits C<speak> from its own base? Because we are no longer using
+C<< -> >> to access C<speak>, the special method look up mechanism wouldn't be
+used, so C<speak> wouldn't even be found!
+
+The second problem is more subtle: C<Animal> is now hardwired into the subroutine
+selection. Let's assume that C<Animal::speak> does exist. What happens when,
+at a later time, someone expands the class hierarchy by having C<Mouse>
+inherit from C<Mus> instead of C<Animal>. Unless the invocation of C<Animal::speak>
+is also changed to an invocation of C<Mus::speak>, centuries worth of taxonomical
+classification could be obliterated!
+
+What we have here is a fragile or leaky abstraction; it is the beginning of a
+maintenance nightmare. What we need is the ability to search for the right
+method wih as few assumptions as possible.
+
+=head2 Starting the search from a different place
+
+A I<better> solution is to tell Perl where in the inheritance chain to begin searching
+for C<speak>. This can be achieved with a modified version of the method arrow C<< -> >>:
+
+ ClassName->FirstPlaceToLook::method
+
+So, the improved C<Mouse> class is:
+
+ # same Animal as before
+ { package Mouse;
+ # same @ISA, &sound as before
+ sub speak {
+ my $class = shift;
+ $class->Animal::speak;
+ print "[but you can barely hear it!]\n";
+ }
+ }
+
+Using this syntax, we start with C<Animal> to find C<speak>, and then
+use all of C<Animal>'s inheritance chain if it is not found immediately.
+As usual, the first parameter to C<speak> would be C<$class>, so we no
+longer need to pass C<$class> explicitly to C<speak>.
+
+But what about the second problem? We're still hardwiring C<Animal> into
+the method lookup.
+
+=head2 The SUPER way of doing things
+
+If C<Animal> is replaced with the special placeholder C<SUPER> in that
+invocation, then the contents of C<Mouse>'s C<@ISA> are used for the
+search, beginning with C<$ISA[0]>. So, all of the problems can be fixed
+as follows:
+
+ # same Animal as before
+ { package Mouse;
+ # same @ISA, &sound as before
+ sub speak {
+ my $class = shift;
+ $class->SUPER::speak;
+ print "[but you can barely hear it!]\n";
+ }
+ }
+
+In general, C<SUPER::speak> means look in the current package's C<@ISA>
+for a class that implements C<speak>, and invoke the first one found.
+The placeholder is called C<SUPER>, because many other languages refer
+to base classes as "I<super>classes", and Perl likes to be eclectic.
+
+Note that a call such as
+
+ $class->SUPER::method;
+
+does I<not> look in the C<@ISA> of C<$class> unless C<$class> happens to
+be the current package.
+
+=head2 Let's review...
+
+So far, we've seen the method arrow syntax:
+
+ Class->method(@args);
+
+or the equivalent:
+
+ $a = "Class";
+ $a->method(@args);
+
+which constructs an argument list of:
+
+ ("Class", @args)
+
+and attempts to invoke:
+
+ Class::method("Class", @args);
+
+However, if C<Class::method> is not found, then C<@Class::ISA> is examined
+(recursively) to locate a class (a package) that does indeed contain C<method>,
+and that subroutine is invoked instead.
+
+Using this simple syntax, we have class methods, (multiple) inheritance,
+overriding, and extending. Using just what we've seen so far, we've
+been able to factor out common code (though that's never a good reason
+for inheritance!), and provide a nice way to reuse implementations with
+variations.
+
+Now, what about data?
+
+=head2 A horse is a horse, of course of course, or is it?
+
+Let's start with the code for the C<Animal> class
+and the C<Horse> class:
+
+ { package Animal;
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ }
+ }
+ { package Horse;
+ @ISA = qw(Animal);
+ sub sound { "neigh" }
+ }
+
+This lets us invoke C<< Horse->speak >> to ripple upward to
+C<Animal::speak>, calling back to C<Horse::sound> to get the specific
+sound, and the output of:
+
+ a Horse goes neigh!
+
+But all of our Horse objects would have to be absolutely identical.
+If we add a subroutine, all horses automatically share it. That's
+great for making horses the same, but how do we capture the
+distinctions of an individual horse? For example, suppose we want
+to give our first horse a name. There's got to be a way to keep its
+name separate from the other horses.
+
+That is to say, we want particular instances of C<Horse> to have
+different names.
+
+In Perl, any reference can be an "instance", so let's start with the
+simplest reference that can hold a horse's name: a scalar reference.
+
+ my $name = "Mr. Ed";
+ my $horse = \$name;
+
+So, now C<$horse> is a reference to what will be the instance-specific
+data (the name). The final step is to turn this reference into a real
+instance of a C<Horse> by using the special operator C<bless>:
+
+ bless $horse, Horse;
+
+This operator stores information about the package named C<Horse> into
+the thing pointed at by the reference. At this point, we say
+C<$horse> is an instance of C<Horse>. That is, it's a specific
+horse. The reference is otherwise unchanged, and can still be used
+with traditional dereferencing operators.
+
+=head2 Invoking an instance method
+
+The method arrow can be used on instances, as well as classes (the names
+of packages). So, let's get the sound that C<$horse> makes:
+
+ my $noise = $horse->sound("some", "unnecessary", "args");
+
+To invoke C<sound>, Perl first notes that C<$horse> is a blessed
+reference (and thus an instance). It then constructs an argument
+list, as per usual.
+
+Now for the fun part: Perl takes the class in which the instance was
+blessed, in this case C<Horse>, and uses that class to locate the
+subroutine. In this case, C<Horse::sound> is found directly (without
+using inheritance). In the end, it is as though our initial line were
+written as follows:
+
+ my $noise = Horse::sound($horse, "some", "unnecessary", "args");
+
+Note that the first parameter here is still the instance, not the name
+of the class as before. We'll get C<neigh> as the return value, and
+that'll end up as the C<$noise> variable above.
+
+If Horse::sound had not been found, we'd be wandering up the C<@Horse::ISA>
+array, trying to find the method in one of the superclasses. The only
+difference between a class method and an instance method is whether the
+first parameter is an instance (a blessed reference) or a class name (a
+string).
+
+=head2 Accessing the instance data
+
+Because we get the instance as the first parameter, we can now access
+the instance-specific data. In this case, let's add a way to get at
+the name:
+
+ { package Horse;
+ @ISA = qw(Animal);
+ sub sound { "neigh" }
+ sub name {
+ my $self = shift;
+ $$self;
+ }
+ }
+
+Inside C<Horse::name>, the C<@_> array contains:
+
+ ($horse, "some", "unnecessary", "args")
+
+so the C<shift> stores C<$horse> into C<$self>. Then, C<$self> gets
+de-referenced with C<$$self> as normal, yielding C<"Mr. Ed">.
+
+It's traditional to C<shift> the first parameter into a variable named
+C<$self> for instance methods and into a variable named C<$class> for
+class methods.
+
+Then, the following line:
+
+ print $horse->name, " says ", $horse->sound, "\n";
+
+outputs:
+
+ Mr. Ed says neigh.
+
+=head2 How to build a horse
+
+Of course, if we constructed all of our horses by hand, we'd most
+likely make mistakes from time to time. We're also violating one of
+the properties of object-oriented programming, in that the "inside
+guts" of a Horse are visible. That's good if you're a veterinarian,
+but not if you just like to own horses. So, let's have the Horse
+class handle the details inside a class method:
+
+ { package Horse;
+ @ISA = qw(Animal);
+ sub sound { "neigh" }
+ sub name {
+ my $self = shift; # instance method, so use $self
+ $$self;
+ }
+ sub named {
+ my $class = shift; # class method, so use $class
+ my $name = shift;
+ bless \$name, $class;
+ }
+ }
+
+Now with the new C<named> method, we can build a horse as follows:
+
+ my $horse = Horse->named("Mr. Ed");
+
+Notice we're back to a class method, so the two arguments to
+C<Horse::named> are C<Horse> and C<Mr. Ed>. The C<bless> operator
+not only blesses C<\$name>, it also returns that reference.
+
+This C<Horse::named> method is called a "constructor".
+
+We've called the constructor C<named> here, so that it quickly denotes
+the constructor's argument as the name for this particular C<Horse>.
+You can use different constructors with different names for different
+ways of "giving birth" to the object (like maybe recording its
+pedigree or date of birth). However, you'll find that most people
+coming to Perl from more limited languages use a single constructor
+named C<new>, with various ways of interpreting the arguments to
+C<new>. Either style is fine, as long as you document your particular
+way of giving birth to an object. (And you I<were> going to do that,
+right?)
+
+=head2 Inheriting the constructor
+
+But was there anything specific to C<Horse> in that method? No. Therefore,
+it's also the same recipe for building anything else that inherited from
+C<Animal>, so let's put C<name> and C<named> there:
+
+ { package Animal;
+ sub speak {
+ my $class = shift;
+ print "a $class goes ", $class->sound, "!\n";
+ }
+ sub name {
+ my $self = shift;
+ $$self;
+ }
+ sub named {
+ my $class = shift;
+ my $name = shift;
+ bless \$name, $class;
+ }
+ }
+ { package Horse;
+ @ISA = qw(Animal);
+ sub sound { "neigh" }
+ }
+
+Ahh, but what happens if we invoke C<speak> on an instance?
+
+ my $horse = Horse->named("Mr. Ed");
+ $horse->speak;
+
+We get a debugging value:
+
+ a Horse=SCALAR(0xaca42ac) goes neigh!
+
+Why? Because the C<Animal::speak> routine is expecting a classname as
+its first parameter, not an instance. When the instance is passed in,
+we'll end up using a blessed scalar reference as a string, and that
+shows up as we saw it just now.
+
+=head2 Making a method work with either classes or instances
+
+All we need is for a method to detect if it is being called on a class
+or called on an instance. The most straightforward way is with the
+C<ref> operator. This returns a string (the classname) when used on a
+blessed reference, and an empty string when used on a string (like a
+classname). Let's modify the C<name> method first to notice the change:
+
+ sub name {
+ my $either = shift;
+ ref $either ? $$either : "Any $either";
+ }
+
+Here, the C<?:> operator comes in handy to select either the
+dereference or a derived string. Now we can use this with either an
+instance or a class. Note that I've changed the first parameter
+holder to C<$either> to show that this is intended:
+
+ my $horse = Horse->named("Mr. Ed");
+ print Horse->name, "\n"; # prints "Any Horse\n"
+ print $horse->name, "\n"; # prints "Mr Ed.\n"
+
+and now we'll fix C<speak> to use this:
+
+ sub speak {
+ my $either = shift;
+ print $either->name, " goes ", $either->sound, "\n";
+ }
+
+And since C<sound> already worked with either a class or an instance,
+we're done!
+
+=head2 Adding parameters to a method
+
+Let's train our animals to eat:
+
+ { package Animal;
+ sub named {
+ my $class = shift;
+ my $name = shift;
+ bless \$name, $class;
+ }
+ sub name {
+ my $either = shift;
+ ref $either ? $$either : "Any $either";
+ }
+ sub speak {
+ my $either = shift;
+ print $either->name, " goes ", $either->sound, "\n";
+ }
+ sub eat {
+ my $either = shift;
+ my $food = shift;
+ print $either->name, " eats $food.\n";
+ }
+ }
+ { package Horse;
+ @ISA = qw(Animal);
+ sub sound { "neigh" }
+ }
+ { package Sheep;
+ @ISA = qw(Animal);
+ sub sound { "baaaah" }
+ }
+
+And now try it out:
+
+ my $horse = Horse->named("Mr. Ed");
+ $horse->eat("hay");
+ Sheep->eat("grass");
+
+which prints:
+
+ Mr. Ed eats hay.
+ Any Sheep eats grass.
+
+An instance method with parameters gets invoked with the instance,
+and then the list of parameters. So that first invocation is like:
+
+ Animal::eat($horse, "hay");
+
+=head2 More interesting instances
+
+What if an instance needs more data? Most interesting instances are
+made of many items, each of which can in turn be a reference or even
+another object. The easiest way to store these is often in a hash.
+The keys of the hash serve as the names of parts of the object (often
+called "instance variables" or "member variables"), and the
+corresponding values are, well, the values.
+
+But how do we turn the horse into a hash? Recall that an object was
+any blessed reference. We can just as easily make it a blessed hash
+reference as a blessed scalar reference, as long as everything that
+looks at the reference is changed accordingly.
+
+Let's make a sheep that has a name and a color:
+
+ my $bad = bless { Name => "Evil", Color => "black" }, Sheep;
+
+so C<< $bad->{Name} >> has C<Evil>, and C<< $bad->{Color} >> has
+C<black>. But we want to make C<< $bad->name >> access the name, and
+that's now messed up because it's expecting a scalar reference. Not
+to worry, because that's pretty easy to fix up.
+
+One solution is to override C<Animal::name> and C<Animal::named> by
+defining them anew in C<Sheep>, but then any methods added later to
+C<Animal> might still mess up, and we'd have to override all of those
+too. Therefore, it's never a good idea to define the data layout in a
+way that's different from the data layout of the base classes. In fact,
+it's a good idea to use blessed hash references in all cases. Also, this
+is why it's important to have constructors do the low-level work. So,
+let's redefine C<Animal>:
+
+ ## in Animal
+ sub name {
+ my $either = shift;
+ ref $either ? $either->{Name} : "Any $either";
+ }
+ sub named {
+ my $class = shift;
+ my $name = shift;
+ my $self = { Name => $name };
+ bless $self, $class;
+ }
+
+Of course, we still need to override C<named> in order to handle
+constructing a C<Sheep> with a certain color:
+
+ ## in Sheep
+ sub named {
+ my ($class, $name) = @_;
+ my $self = $class->SUPER::named(@_);
+ $$self{Color} = $class->default_color;
+ $self
+ }
+
+(Note that C<@_> contains the parameters to C<named>.)
+
+What's this C<default_color>? Well, if C<named> has only the name,
+we still need to set a color, so we'll have a class-specific default color.
+For a sheep, we might define it as white:
+
+ ## in Sheep
+ sub default_color { "white" }
+
+Now:
+
+ my $sheep = Sheep->named("Bad");
+ print $sheep->{Color}, "\n";
+
+outputs:
+
+ white
+
+Now, there's nothing particularly specific to C<Sheep> when it comes
+to color, so let's remove C<Sheep::named> and implement C<Animal::named>
+to handle color instead:
+
+ ## in Animal
+ sub named {
+ my ($class, $name) = @_;
+ my $self = { Name => $name, Color => $class->default_color };
+ bless $self, $class;
+ }
+
+And then to keep from having to define C<default_color> for each additional
+class, we'll define a method that serves as the "default default" directly
+in C<Animal>:
+
+ ## in Animal
+ sub default_color { "brown" }
+
+Of course, because C<name> and C<named> were the only methods that
+referenced the "structure" of the object, the rest of the methods can
+remain the same, so C<speak> still works as before.
+
+=head2 A horse of a different color
+
+But having all our horses be brown would be boring. So let's add a
+method or two to get and set the color.
+
+ ## in Animal
+ sub color {
+ $_[0]->{Color}
+ }
+ sub set_color {
+ $_[0]->{Color} = $_[1];
+ }
+
+Note the alternate way of accessing the arguments: C<$_[0]> is used
+in-place, rather than with a C<shift>. (This saves us a bit of time
+for something that may be invoked frequently.) And now we can fix
+that color for Mr. Ed:
+
+ my $horse = Horse->named("Mr. Ed");
+ $horse->set_color("black-and-white");
+ print $horse->name, " is colored ", $horse->color, "\n";
+
+which results in:
+
+ Mr. Ed is colored black-and-white
+
+=head2 Summary
+
+So, now we have class methods, constructors, instance methods, instance
+data, and even accessors. But that's still just the beginning of what
+Perl has to offer. We haven't even begun to talk about accessors that
+double as getters and setters, destructors, indirect object notation,
+overloading, "isa" and "can" tests, the C<UNIVERSAL> class, and so on.
+That's for the rest of the Perl documentation to cover. Hopefully, this
+gets you started, though.
+
+=head1 SEE ALSO
+
+For more information, see L<perlobj> (for all the gritty details about
+Perl objects, now that you've seen the basics), L<perltoot> (the
+tutorial for those who already know objects), L<perltooc> (dealing
+with class data), L<perlbot> (for some more tricks), and books such as
+Damian Conway's excellent I<Object Oriented Perl>.
+
+Some modules which might prove interesting are Class::Accessor,
+Class::Class, Class::Contract, Class::Data::Inheritable,
+Class::MethodMaker and Tie::SecureHash
+
+=head1 COPYRIGHT
+
+Copyright (c) 1999, 2000 by Randal L. Schwartz and Stonehenge
+Consulting Services, Inc.
+
+Copyright (c) 2009 by Michael F. Witten.
+
+Permission is hereby granted to distribute this document intact with
+the Perl distribution, and in accordance with the licenses of the Perl
+distribution; derived documents must include this copyright notice
+intact.
+
+Portions of this text have been derived from Perl Training materials
+originally appearing in the I<Packages, References, Objects, and
+Modules> course taught by instructors for Stonehenge Consulting
+Services, Inc. and used with permission.
+
+Portions of this text have been derived from materials originally
+appearing in I<Linux Magazine> and used with permission.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlbot.pod b/Master/tlpkg/tlperl/lib/pods/perlbot.pod
new file mode 100644
index 00000000000..91723b70d78
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlbot.pod
@@ -0,0 +1,535 @@
+=head1 NAME
+
+perlbot - Bag'o Object Tricks (the BOT)
+
+=head1 DESCRIPTION
+
+The following collection of tricks and hints is intended to whet curious
+appetites about such things as the use of instance variables and the
+mechanics of object and class relationships. The reader is encouraged to
+consult relevant textbooks for discussion of Object Oriented definitions and
+methodology. This is not intended as a tutorial for object-oriented
+programming or as a comprehensive guide to Perl's object oriented features,
+nor should it be construed as a style guide. If you're looking for tutorials,
+be sure to read L<perlboot>, L<perltoot>, and L<perltooc>.
+
+The Perl motto still holds: There's more than one way to do it.
+
+=head1 OO SCALING TIPS
+
+=over 5
+
+=item 1
+
+Do not attempt to verify the type of $self. That'll break if the class is
+inherited, when the type of $self is valid but its package isn't what you
+expect. See rule 5.
+
+=item 2
+
+If an object-oriented (OO) or indirect-object (IO) syntax was used, then the
+object is probably the correct type and there's no need to become paranoid
+about it. Perl isn't a paranoid language anyway. If people subvert the OO
+or IO syntax then they probably know what they're doing and you should let
+them do it. See rule 1.
+
+=item 3
+
+Use the two-argument form of bless(). Let a subclass use your constructor.
+See L<INHERITING A CONSTRUCTOR>.
+
+=item 4
+
+The subclass is allowed to know things about its immediate superclass, the
+superclass is allowed to know nothing about a subclass.
+
+=item 5
+
+Don't be trigger happy with inheritance. A "using", "containing", or
+"delegation" relationship (some sort of aggregation, at least) is often more
+appropriate. See L<OBJECT RELATIONSHIPS>, L<USING RELATIONSHIP WITH SDBM>,
+and L<"DELEGATION">.
+
+=item 6
+
+The object is the namespace. Make package globals accessible via the
+object. This will remove the guess work about the symbol's home package.
+See L<CLASS CONTEXT AND THE OBJECT>.
+
+=item 7
+
+IO syntax is certainly less noisy, but it is also prone to ambiguities that
+can cause difficult-to-find bugs. Allow people to use the sure-thing OO
+syntax, even if you don't like it.
+
+=item 8
+
+Do not use function-call syntax on a method. You're going to be bitten
+someday. Someone might move that method into a superclass and your code
+will be broken. On top of that you're feeding the paranoia in rule 2.
+
+=item 9
+
+Don't assume you know the home package of a method. You're making it
+difficult for someone to override that method. See L<THINKING OF CODE REUSE>.
+
+=back
+
+=head1 INSTANCE VARIABLES
+
+An anonymous array or anonymous hash can be used to hold instance
+variables. Named parameters are also demonstrated.
+
+ package Foo;
+
+ sub new {
+ my $type = shift;
+ my %params = @_;
+ my $self = {};
+ $self->{'High'} = $params{'High'};
+ $self->{'Low'} = $params{'Low'};
+ bless $self, $type;
+ }
+
+
+ package Bar;
+
+ sub new {
+ my $type = shift;
+ my %params = @_;
+ my $self = [];
+ $self->[0] = $params{'Left'};
+ $self->[1] = $params{'Right'};
+ bless $self, $type;
+ }
+
+ package main;
+
+ $a = Foo->new( 'High' => 42, 'Low' => 11 );
+ print "High=$a->{'High'}\n";
+ print "Low=$a->{'Low'}\n";
+
+ $b = Bar->new( 'Left' => 78, 'Right' => 40 );
+ print "Left=$b->[0]\n";
+ print "Right=$b->[1]\n";
+
+=head1 SCALAR INSTANCE VARIABLES
+
+An anonymous scalar can be used when only one instance variable is needed.
+
+ package Foo;
+
+ sub new {
+ my $type = shift;
+ my $self;
+ $self = shift;
+ bless \$self, $type;
+ }
+
+ package main;
+
+ $a = Foo->new( 42 );
+ print "a=$$a\n";
+
+
+=head1 INSTANCE VARIABLE INHERITANCE
+
+This example demonstrates how one might inherit instance variables from a
+superclass for inclusion in the new class. This requires calling the
+superclass's constructor and adding one's own instance variables to the new
+object.
+
+ package Bar;
+
+ sub new {
+ my $type = shift;
+ my $self = {};
+ $self->{'buz'} = 42;
+ bless $self, $type;
+ }
+
+ package Foo;
+ @ISA = qw( Bar );
+
+ sub new {
+ my $type = shift;
+ my $self = Bar->new;
+ $self->{'biz'} = 11;
+ bless $self, $type;
+ }
+
+ package main;
+
+ $a = Foo->new;
+ print "buz = ", $a->{'buz'}, "\n";
+ print "biz = ", $a->{'biz'}, "\n";
+
+
+
+=head1 OBJECT RELATIONSHIPS
+
+The following demonstrates how one might implement "containing" and "using"
+relationships between objects.
+
+ package Bar;
+
+ sub new {
+ my $type = shift;
+ my $self = {};
+ $self->{'buz'} = 42;
+ bless $self, $type;
+ }
+
+ package Foo;
+
+ sub new {
+ my $type = shift;
+ my $self = {};
+ $self->{'Bar'} = Bar->new;
+ $self->{'biz'} = 11;
+ bless $self, $type;
+ }
+
+ package main;
+
+ $a = Foo->new;
+ print "buz = ", $a->{'Bar'}->{'buz'}, "\n";
+ print "biz = ", $a->{'biz'}, "\n";
+
+
+
+=head1 OVERRIDING SUPERCLASS METHODS
+
+The following example demonstrates how to override a superclass method and
+then call the overridden method. The B<SUPER> pseudo-class allows the
+programmer to call an overridden superclass method without actually knowing
+where that method is defined.
+
+ package Buz;
+ sub goo { print "here's the goo\n" }
+
+ package Bar; @ISA = qw( Buz );
+ sub google { print "google here\n" }
+
+ package Baz;
+ sub mumble { print "mumbling\n" }
+
+ package Foo;
+ @ISA = qw( Bar Baz );
+
+ sub new {
+ my $type = shift;
+ bless [], $type;
+ }
+ sub grr { print "grumble\n" }
+ sub goo {
+ my $self = shift;
+ $self->SUPER::goo();
+ }
+ sub mumble {
+ my $self = shift;
+ $self->SUPER::mumble();
+ }
+ sub google {
+ my $self = shift;
+ $self->SUPER::google();
+ }
+
+ package main;
+
+ $foo = Foo->new;
+ $foo->mumble;
+ $foo->grr;
+ $foo->goo;
+ $foo->google;
+
+Note that C<SUPER> refers to the superclasses of the current package
+(C<Foo>), not to the superclasses of C<$self>.
+
+
+=head1 USING RELATIONSHIP WITH SDBM
+
+This example demonstrates an interface for the SDBM class. This creates a
+"using" relationship between the SDBM class and the new class Mydbm.
+
+ package Mydbm;
+
+ require SDBM_File;
+ require Tie::Hash;
+ @ISA = qw( Tie::Hash );
+
+ sub TIEHASH {
+ my $type = shift;
+ my $ref = SDBM_File->new(@_);
+ bless {'dbm' => $ref}, $type;
+ }
+ sub FETCH {
+ my $self = shift;
+ my $ref = $self->{'dbm'};
+ $ref->FETCH(@_);
+ }
+ sub STORE {
+ my $self = shift;
+ if (defined $_[0]){
+ my $ref = $self->{'dbm'};
+ $ref->STORE(@_);
+ } else {
+ die "Cannot STORE an undefined key in Mydbm\n";
+ }
+ }
+
+ package main;
+ use Fcntl qw( O_RDWR O_CREAT );
+
+ tie %foo, "Mydbm", "Sdbm", O_RDWR|O_CREAT, 0640;
+ $foo{'bar'} = 123;
+ print "foo-bar = $foo{'bar'}\n";
+
+ tie %bar, "Mydbm", "Sdbm2", O_RDWR|O_CREAT, 0640;
+ $bar{'Cathy'} = 456;
+ print "bar-Cathy = $bar{'Cathy'}\n";
+
+=head1 THINKING OF CODE REUSE
+
+One strength of Object-Oriented languages is the ease with which old code
+can use new code. The following examples will demonstrate first how one can
+hinder code reuse and then how one can promote code reuse.
+
+This first example illustrates a class which uses a fully-qualified method
+call to access the "private" method BAZ(). The second example will show
+that it is impossible to override the BAZ() method.
+
+ package FOO;
+
+ sub new {
+ my $type = shift;
+ bless {}, $type;
+ }
+ sub bar {
+ my $self = shift;
+ $self->FOO::private::BAZ;
+ }
+
+ package FOO::private;
+
+ sub BAZ {
+ print "in BAZ\n";
+ }
+
+ package main;
+
+ $a = FOO->new;
+ $a->bar;
+
+Now we try to override the BAZ() method. We would like FOO::bar() to call
+GOOP::BAZ(), but this cannot happen because FOO::bar() explicitly calls
+FOO::private::BAZ().
+
+ package FOO;
+
+ sub new {
+ my $type = shift;
+ bless {}, $type;
+ }
+ sub bar {
+ my $self = shift;
+ $self->FOO::private::BAZ;
+ }
+
+ package FOO::private;
+
+ sub BAZ {
+ print "in BAZ\n";
+ }
+
+ package GOOP;
+ @ISA = qw( FOO );
+ sub new {
+ my $type = shift;
+ bless {}, $type;
+ }
+
+ sub BAZ {
+ print "in GOOP::BAZ\n";
+ }
+
+ package main;
+
+ $a = GOOP->new;
+ $a->bar;
+
+To create reusable code we must modify class FOO, flattening class
+FOO::private. The next example shows a reusable class FOO which allows the
+method GOOP::BAZ() to be used in place of FOO::BAZ().
+
+ package FOO;
+
+ sub new {
+ my $type = shift;
+ bless {}, $type;
+ }
+ sub bar {
+ my $self = shift;
+ $self->BAZ;
+ }
+
+ sub BAZ {
+ print "in BAZ\n";
+ }
+
+ package GOOP;
+ @ISA = qw( FOO );
+
+ sub new {
+ my $type = shift;
+ bless {}, $type;
+ }
+ sub BAZ {
+ print "in GOOP::BAZ\n";
+ }
+
+ package main;
+
+ $a = GOOP->new;
+ $a->bar;
+
+=head1 CLASS CONTEXT AND THE OBJECT
+
+Use the object to solve package and class context problems. Everything a
+method needs should be available via the object or should be passed as a
+parameter to the method.
+
+A class will sometimes have static or global data to be used by the
+methods. A subclass may want to override that data and replace it with new
+data. When this happens the superclass may not know how to find the new
+copy of the data.
+
+This problem can be solved by using the object to define the context of the
+method. Let the method look in the object for a reference to the data. The
+alternative is to force the method to go hunting for the data ("Is it in my
+class, or in a subclass? Which subclass?"), and this can be inconvenient
+and will lead to hackery. It is better just to let the object tell the
+method where that data is located.
+
+ package Bar;
+
+ %fizzle = ( 'Password' => 'XYZZY' );
+
+ sub new {
+ my $type = shift;
+ my $self = {};
+ $self->{'fizzle'} = \%fizzle;
+ bless $self, $type;
+ }
+
+ sub enter {
+ my $self = shift;
+
+ # Don't try to guess if we should use %Bar::fizzle
+ # or %Foo::fizzle. The object already knows which
+ # we should use, so just ask it.
+ #
+ my $fizzle = $self->{'fizzle'};
+
+ print "The word is ", $fizzle->{'Password'}, "\n";
+ }
+
+ package Foo;
+ @ISA = qw( Bar );
+
+ %fizzle = ( 'Password' => 'Rumple' );
+
+ sub new {
+ my $type = shift;
+ my $self = Bar->new;
+ $self->{'fizzle'} = \%fizzle;
+ bless $self, $type;
+ }
+
+ package main;
+
+ $a = Bar->new;
+ $b = Foo->new;
+ $a->enter;
+ $b->enter;
+
+=head1 INHERITING A CONSTRUCTOR
+
+An inheritable constructor should use the second form of bless() which allows
+blessing directly into a specified class. Notice in this example that the
+object will be a BAR not a FOO, even though the constructor is in class FOO.
+
+ package FOO;
+
+ sub new {
+ my $type = shift;
+ my $self = {};
+ bless $self, $type;
+ }
+
+ sub baz {
+ print "in FOO::baz()\n";
+ }
+
+ package BAR;
+ @ISA = qw(FOO);
+
+ sub baz {
+ print "in BAR::baz()\n";
+ }
+
+ package main;
+
+ $a = BAR->new;
+ $a->baz;
+
+=head1 DELEGATION
+
+Some classes, such as SDBM_File, cannot be effectively subclassed because
+they create foreign objects. Such a class can be extended with some sort of
+aggregation technique such as the "using" relationship mentioned earlier or
+by delegation.
+
+The following example demonstrates delegation using an AUTOLOAD() function to
+perform message-forwarding. This will allow the Mydbm object to behave
+exactly like an SDBM_File object. The Mydbm class could now extend the
+behavior by adding custom FETCH() and STORE() methods, if this is desired.
+
+ package Mydbm;
+
+ require SDBM_File;
+ require Tie::Hash;
+ @ISA = qw(Tie::Hash);
+
+ sub TIEHASH {
+ my $type = shift;
+ my $ref = SDBM_File->new(@_);
+ bless {'delegate' => $ref};
+ }
+
+ sub AUTOLOAD {
+ my $self = shift;
+
+ # The Perl interpreter places the name of the
+ # message in a variable called $AUTOLOAD.
+
+ # DESTROY messages should never be propagated.
+ return if $AUTOLOAD =~ /::DESTROY$/;
+
+ # Remove the package name.
+ $AUTOLOAD =~ s/^Mydbm:://;
+
+ # Pass the message to the delegate.
+ $self->{'delegate'}->$AUTOLOAD(@_);
+ }
+
+ package main;
+ use Fcntl qw( O_RDWR O_CREAT );
+
+ tie %foo, "Mydbm", "adbm", O_RDWR|O_CREAT, 0640;
+ $foo{'bar'} = 123;
+ print "foo-bar = $foo{'bar'}\n";
+
+=head1 SEE ALSO
+
+L<perlboot>, L<perltoot>, L<perltooc>.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlbs2000.pod b/Master/tlpkg/tlperl/lib/pods/perlbs2000.pod
new file mode 100644
index 00000000000..a7746c64e2b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlbs2000.pod
@@ -0,0 +1,241 @@
+This document is written in pod format hence there are punctuation
+characters in odd places. Do not worry, you've apparently got the
+ASCII->EBCDIC translation worked out correctly. You can read more
+about pod in pod/perlpod.pod or the short summary in the INSTALL file.
+
+=head1 NAME
+
+README.BS2000 - building and installing Perl for BS2000.
+
+=head1 SYNOPSIS
+
+This document will help you Configure, build, test and install Perl
+on BS2000 in the POSIX subsystem.
+
+=head1 DESCRIPTION
+
+This is a ported perl for the POSIX subsystem in BS2000 VERSION OSD
+V3.1A or later. It may work on other versions, but we started porting
+and testing it with 3.1A and are currently using Version V4.0A.
+
+You may need the following GNU programs in order to install perl:
+
+=head2 gzip on BS2000
+
+We used version 1.2.4, which could be installed out of the box with
+one failure during 'make check'.
+
+=head2 bison on BS2000
+
+The yacc coming with BS2000 POSIX didn't work for us. So we had to
+use bison. We had to make a few changes to perl in order to use the
+pure (reentrant) parser of bison. We used version 1.25, but we had to
+add a few changes due to EBCDIC. See below for more details
+concerning yacc.
+
+=head2 Unpacking Perl Distribution on BS2000
+
+To extract an ASCII tar archive on BS2000 POSIX you need an ASCII
+filesystem (we used the mountpoint /usr/local/ascii for this). Now
+you extract the archive in the ASCII filesystem without
+I/O-conversion:
+
+cd /usr/local/ascii
+export IO_CONVERSION=NO
+gunzip < /usr/local/src/perl.tar.gz | pax -r
+
+You may ignore the error message for the first element of the archive
+(this doesn't look like a tar archive / skipping to next file...),
+it's only the directory which will be created automatically anyway.
+
+After extracting the archive you copy the whole directory tree to your
+EBCDIC filesystem. B<This time you use I/O-conversion>:
+
+cd /usr/local/src
+IO_CONVERSION=YES
+cp -r /usr/local/ascii/perl5.005_02 ./
+
+=head2 Compiling Perl on BS2000
+
+There is a "hints" file for BS2000 called hints.posix-bc (because
+posix-bc is the OS name given by `uname`) that specifies the correct
+values for most things. The major problem is (of course) the EBCDIC
+character set. We have german EBCDIC version.
+
+Because of our problems with the native yacc we used GNU bison to
+generate a pure (=reentrant) parser for perly.y. So our yacc is
+really the following script:
+
+-----8<-----/usr/local/bin/yacc-----8<-----
+#! /usr/bin/sh
+
+# Bison as a reentrant yacc:
+
+# save parameters:
+params=""
+while [[ $# -gt 1 ]]; do
+ params="$params $1"
+ shift
+done
+
+# add flag %pure_parser:
+
+tmpfile=/tmp/bison.$$.y
+echo %pure_parser > $tmpfile
+cat $1 >> $tmpfile
+
+# call bison:
+
+echo "/usr/local/bin/bison --yacc $params $1\t\t\t(Pure Parser)"
+/usr/local/bin/bison --yacc $params $tmpfile
+
+# cleanup:
+
+rm -f $tmpfile
+-----8<----------8<-----
+
+We still use the normal yacc for a2p.y though!!! We made a softlink
+called byacc to distinguish between the two versions:
+
+ln -s /usr/bin/yacc /usr/local/bin/byacc
+
+We build perl using GNU make. We tried the native make once and it
+worked too.
+
+=head2 Testing Perl on BS2000
+
+We still got a few errors during C<make test>. Some of them are the
+result of using bison. Bison prints I<parser error> instead of I<syntax
+error>, so we may ignore them. The following list shows
+our errors, your results may differ:
+
+op/numconvert.......FAILED tests 1409-1440
+op/regexp...........FAILED tests 483, 496
+op/regexp_noamp.....FAILED tests 483, 496
+pragma/overload.....FAILED tests 152-153, 170-171
+pragma/warnings.....FAILED tests 14, 82, 129, 155, 192, 205, 207
+lib/bigfloat........FAILED tests 351-352, 355
+lib/bigfltpm........FAILED tests 354-355, 358
+lib/complex.........FAILED tests 267, 487
+lib/dumper..........FAILED tests 43, 45
+Failed 11/231 test scripts, 95.24% okay. 57/10595 subtests failed, 99.46% okay.
+
+=head2 Installing Perl on BS2000
+
+We have no nroff on BS2000 POSIX (yet), so we ignored any errors while
+installing the documentation.
+
+
+=head2 Using Perl in the Posix-Shell of BS2000
+
+BS2000 POSIX doesn't support the shebang notation
+(C<#!/usr/local/bin/perl>), so you have to use the following lines
+instead:
+
+: # use perl
+ eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
+ if $running_under_some_shell;
+
+=head2 Using Perl in "native" BS2000
+
+We don't have much experience with this yet, but try the following:
+
+Copy your Perl executable to a BS2000 LLM using bs2cp:
+
+C<bs2cp /usr/local/bin/perl 'bs2:perl(perl,l)'>
+
+Now you can start it with the following (SDF) command:
+
+C</START-PROG FROM-FILE=*MODULE(PERL,PERL),PROG-MODE=*ANY,RUN-MODE=*ADV>
+
+First you get the BS2000 commandline prompt ('*'). Here you may enter
+your parameters, e.g. C<-e 'print "Hello World!\\n";'> (note the
+double backslash!) or C<-w> and the name of your Perl script.
+Filenames starting with C</> are searched in the Posix filesystem,
+others are searched in the BS2000 filesystem. You may even use
+wildcards if you put a C<%> in front of your filename (e.g. C<-w
+checkfiles.pl %*.c>). Read your C/C++ manual for additional
+possibilities of the commandline prompt (look for
+PARAMETER-PROMPTING).
+
+=head2 Floating point anomalies on BS2000
+
+There appears to be a bug in the floating point implementation on BS2000 POSIX
+systems such that calling int() on the product of a number and a small
+magnitude number is not the same as calling int() on the quotient of
+that number and a large magnitude number. For example, in the following
+Perl code:
+
+ my $x = 100000.0;
+ my $y = int($x * 1e-5) * 1e5; # '0'
+ my $z = int($x / 1e+5) * 1e5; # '100000'
+ print "\$y is $y and \$z is $z\n"; # $y is 0 and $z is 100000
+
+Although one would expect the quantities $y and $z to be the same and equal
+to 100000 they will differ and instead will be 0 and 100000 respectively.
+
+=head2 Using PerlIO and different encodings on ASCII and EBCDIC partitions
+
+Since version 5.8 Perl uses the new PerlIO on BS2000. This enables
+you using different encodings per IO channel. For example you may use
+
+ use Encode;
+ open($f, ">:encoding(ascii)", "test.ascii");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(posix-bc)", "test.ebcdic");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(latin1)", "test.latin1");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(utf8)", "test.utf8");
+ print $f "Hello World!\n";
+
+to get two files containing "Hello World!\n" in ASCII, EBCDIC, ISO
+Latin-1 (in this example identical to ASCII) respective UTF-EBCDIC (in
+this example identical to normal EBCDIC). See the documentation of
+Encode::PerlIO for details.
+
+As the PerlIO layer uses raw IO internally, all this totally ignores
+the type of your filesystem (ASCII or EBCDIC) and the IO_CONVERSION
+environment variable. If you want to get the old behavior, that the
+BS2000 IO functions determine conversion depending on the filesystem
+PerlIO still is your friend. You use IO_CONVERSION as usual and tell
+Perl, that it should use the native IO layer:
+
+ export IO_CONVERSION=YES
+ export PERLIO=stdio
+
+Now your IO would be ASCII on ASCII partitions and EBCDIC on EBCDIC
+partitions. See the documentation of PerlIO (without C<Encode::>!)
+for further posibilities.
+
+=head1 AUTHORS
+
+Thomas Dorner
+
+=head1 SEE ALSO
+
+L<INSTALL>, L<perlport>.
+
+=head2 Mailing list
+
+If you are interested in the VM/ESA, z/OS (formerly known as OS/390)
+and POSIX-BC (BS2000) ports of Perl then see the perl-mvs mailing list.
+To subscribe, send an empty message to perl-mvs-subscribe@perl.org.
+
+See also:
+
+ http://lists.perl.org/showlist.cgi?name=perl-mvs
+
+There are web archives of the mailing list at:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl-mvs/
+ http://archive.develooper.com/perl-mvs@perl.org/
+
+=head1 HISTORY
+
+This document was originally written by Thomas Dorner for the 5.005
+release of Perl.
+
+This document was podified for the 5.6 release of perl 11 July 2000.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcall.pod b/Master/tlpkg/tlperl/lib/pods/perlcall.pod
new file mode 100644
index 00000000000..359e097a18d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcall.pod
@@ -0,0 +1,1935 @@
+=head1 NAME
+
+perlcall - Perl calling conventions from C
+
+=head1 DESCRIPTION
+
+The purpose of this document is to show you how to call Perl subroutines
+directly from C, i.e., how to write I<callbacks>.
+
+Apart from discussing the C interface provided by Perl for writing
+callbacks the document uses a series of examples to show how the
+interface actually works in practice. In addition some techniques for
+coding callbacks are covered.
+
+Examples where callbacks are necessary include
+
+=over 5
+
+=item * An Error Handler
+
+You have created an XSUB interface to an application's C API.
+
+A fairly common feature in applications is to allow you to define a C
+function that will be called whenever something nasty occurs. What we
+would like is to be able to specify a Perl subroutine that will be
+called instead.
+
+=item * An Event Driven Program
+
+The classic example of where callbacks are used is when writing an
+event driven program like for an X windows application. In this case
+you register functions to be called whenever specific events occur,
+e.g., a mouse button is pressed, the cursor moves into a window or a
+menu item is selected.
+
+=back
+
+Although the techniques described here are applicable when embedding
+Perl in a C program, this is not the primary goal of this document.
+There are other details that must be considered and are specific to
+embedding Perl. For details on embedding Perl in C refer to
+L<perlembed>.
+
+Before you launch yourself head first into the rest of this document,
+it would be a good idea to have read the following two documents -
+L<perlxs> and L<perlguts>.
+
+=head1 THE CALL_ FUNCTIONS
+
+Although this stuff is easier to explain using examples, you first need
+be aware of a few important definitions.
+
+Perl has a number of C functions that allow you to call Perl
+subroutines. They are
+
+ I32 call_sv(SV* sv, I32 flags);
+ I32 call_pv(char *subname, I32 flags);
+ I32 call_method(char *methname, I32 flags);
+ I32 call_argv(char *subname, I32 flags, register char **argv);
+
+The key function is I<call_sv>. All the other functions are
+fairly simple wrappers which make it easier to call Perl subroutines in
+special cases. At the end of the day they will all call I<call_sv>
+to invoke the Perl subroutine.
+
+All the I<call_*> functions have a C<flags> parameter which is
+used to pass a bit mask of options to Perl. This bit mask operates
+identically for each of the functions. The settings available in the
+bit mask are discussed in L<FLAG VALUES>.
+
+Each of the functions will now be discussed in turn.
+
+=over 5
+
+=item call_sv
+
+I<call_sv> takes two parameters, the first, C<sv>, is an SV*.
+This allows you to specify the Perl subroutine to be called either as a
+C string (which has first been converted to an SV) or a reference to a
+subroutine. The section, I<Using call_sv>, shows how you can make
+use of I<call_sv>.
+
+=item call_pv
+
+The function, I<call_pv>, is similar to I<call_sv> except it
+expects its first parameter to be a C char* which identifies the Perl
+subroutine you want to call, e.g., C<call_pv("fred", 0)>. If the
+subroutine you want to call is in another package, just include the
+package name in the string, e.g., C<"pkg::fred">.
+
+=item call_method
+
+The function I<call_method> is used to call a method from a Perl
+class. The parameter C<methname> corresponds to the name of the method
+to be called. Note that the class that the method belongs to is passed
+on the Perl stack rather than in the parameter list. This class can be
+either the name of the class (for a static method) or a reference to an
+object (for a virtual method). See L<perlobj> for more information on
+static and virtual methods and L<Using call_method> for an example
+of using I<call_method>.
+
+=item call_argv
+
+I<call_argv> calls the Perl subroutine specified by the C string
+stored in the C<subname> parameter. It also takes the usual C<flags>
+parameter. The final parameter, C<argv>, consists of a NULL terminated
+list of C strings to be passed as parameters to the Perl subroutine.
+See I<Using call_argv>.
+
+=back
+
+All the functions return an integer. This is a count of the number of
+items returned by the Perl subroutine. The actual items returned by the
+subroutine are stored on the Perl stack.
+
+As a general rule you should I<always> check the return value from
+these functions. Even if you are expecting only a particular number of
+values to be returned from the Perl subroutine, there is nothing to
+stop someone from doing something unexpected--don't say you haven't
+been warned.
+
+=head1 FLAG VALUES
+
+The C<flags> parameter in all the I<call_*> functions is a bit mask
+which can consist of any combination of the symbols defined below,
+OR'ed together.
+
+
+=head2 G_VOID
+
+Calls the Perl subroutine in a void context.
+
+This flag has 2 effects:
+
+=over 5
+
+=item 1.
+
+It indicates to the subroutine being called that it is executing in
+a void context (if it executes I<wantarray> the result will be the
+undefined value).
+
+=item 2.
+
+It ensures that nothing is actually returned from the subroutine.
+
+=back
+
+The value returned by the I<call_*> function indicates how many
+items have been returned by the Perl subroutine - in this case it will
+be 0.
+
+
+=head2 G_SCALAR
+
+Calls the Perl subroutine in a scalar context. This is the default
+context flag setting for all the I<call_*> functions.
+
+This flag has 2 effects:
+
+=over 5
+
+=item 1.
+
+It indicates to the subroutine being called that it is executing in a
+scalar context (if it executes I<wantarray> the result will be false).
+
+=item 2.
+
+It ensures that only a scalar is actually returned from the subroutine.
+The subroutine can, of course, ignore the I<wantarray> and return a
+list anyway. If so, then only the last element of the list will be
+returned.
+
+=back
+
+The value returned by the I<call_*> function indicates how many
+items have been returned by the Perl subroutine - in this case it will
+be either 0 or 1.
+
+If 0, then you have specified the G_DISCARD flag.
+
+If 1, then the item actually returned by the Perl subroutine will be
+stored on the Perl stack - the section I<Returning a Scalar> shows how
+to access this value on the stack. Remember that regardless of how
+many items the Perl subroutine returns, only the last one will be
+accessible from the stack - think of the case where only one value is
+returned as being a list with only one element. Any other items that
+were returned will not exist by the time control returns from the
+I<call_*> function. The section I<Returning a list in a scalar
+context> shows an example of this behavior.
+
+
+=head2 G_ARRAY
+
+Calls the Perl subroutine in a list context.
+
+As with G_SCALAR, this flag has 2 effects:
+
+=over 5
+
+=item 1.
+
+It indicates to the subroutine being called that it is executing in a
+list context (if it executes I<wantarray> the result will be true).
+
+
+=item 2.
+
+It ensures that all items returned from the subroutine will be
+accessible when control returns from the I<call_*> function.
+
+=back
+
+The value returned by the I<call_*> function indicates how many
+items have been returned by the Perl subroutine.
+
+If 0, then you have specified the G_DISCARD flag.
+
+If not 0, then it will be a count of the number of items returned by
+the subroutine. These items will be stored on the Perl stack. The
+section I<Returning a list of values> gives an example of using the
+G_ARRAY flag and the mechanics of accessing the returned items from the
+Perl stack.
+
+=head2 G_DISCARD
+
+By default, the I<call_*> functions place the items returned from
+by the Perl subroutine on the stack. If you are not interested in
+these items, then setting this flag will make Perl get rid of them
+automatically for you. Note that it is still possible to indicate a
+context to the Perl subroutine by using either G_SCALAR or G_ARRAY.
+
+If you do not set this flag then it is I<very> important that you make
+sure that any temporaries (i.e., parameters passed to the Perl
+subroutine and values returned from the subroutine) are disposed of
+yourself. The section I<Returning a Scalar> gives details of how to
+dispose of these temporaries explicitly and the section I<Using Perl to
+dispose of temporaries> discusses the specific circumstances where you
+can ignore the problem and let Perl deal with it for you.
+
+=head2 G_NOARGS
+
+Whenever a Perl subroutine is called using one of the I<call_*>
+functions, it is assumed by default that parameters are to be passed to
+the subroutine. If you are not passing any parameters to the Perl
+subroutine, you can save a bit of time by setting this flag. It has
+the effect of not creating the C<@_> array for the Perl subroutine.
+
+Although the functionality provided by this flag may seem
+straightforward, it should be used only if there is a good reason to do
+so. The reason for being cautious is that even if you have specified
+the G_NOARGS flag, it is still possible for the Perl subroutine that
+has been called to think that you have passed it parameters.
+
+In fact, what can happen is that the Perl subroutine you have called
+can access the C<@_> array from a previous Perl subroutine. This will
+occur when the code that is executing the I<call_*> function has
+itself been called from another Perl subroutine. The code below
+illustrates this
+
+ sub fred
+ { print "@_\n" }
+
+ sub joe
+ { &fred }
+
+ &joe(1,2,3);
+
+This will print
+
+ 1 2 3
+
+What has happened is that C<fred> accesses the C<@_> array which
+belongs to C<joe>.
+
+
+=head2 G_EVAL
+
+It is possible for the Perl subroutine you are calling to terminate
+abnormally, e.g., by calling I<die> explicitly or by not actually
+existing. By default, when either of these events occurs, the
+process will terminate immediately. If you want to trap this
+type of event, specify the G_EVAL flag. It will put an I<eval { }>
+around the subroutine call.
+
+Whenever control returns from the I<call_*> function you need to
+check the C<$@> variable as you would in a normal Perl script.
+
+The value returned from the I<call_*> function is dependent on
+what other flags have been specified and whether an error has
+occurred. Here are all the different cases that can occur:
+
+=over 5
+
+=item *
+
+If the I<call_*> function returns normally, then the value
+returned is as specified in the previous sections.
+
+=item *
+
+If G_DISCARD is specified, the return value will always be 0.
+
+=item *
+
+If G_ARRAY is specified I<and> an error has occurred, the return value
+will always be 0.
+
+=item *
+
+If G_SCALAR is specified I<and> an error has occurred, the return value
+will be 1 and the value on the top of the stack will be I<undef>. This
+means that if you have already detected the error by checking C<$@> and
+you want the program to continue, you must remember to pop the I<undef>
+from the stack.
+
+=back
+
+See I<Using G_EVAL> for details on using G_EVAL.
+
+=head2 G_KEEPERR
+
+You may have noticed that using the G_EVAL flag described above will
+B<always> clear the C<$@> variable and set it to a string describing
+the error iff there was an error in the called code. This unqualified
+resetting of C<$@> can be problematic in the reliable identification of
+errors using the C<eval {}> mechanism, because the possibility exists
+that perl will call other code (end of block processing code, for
+example) between the time the error causes C<$@> to be set within
+C<eval {}>, and the subsequent statement which checks for the value of
+C<$@> gets executed in the user's script.
+
+This scenario will mostly be applicable to code that is meant to be
+called from within destructors, asynchronous callbacks, signal
+handlers, C<__DIE__> or C<__WARN__> hooks, and C<tie> functions. In
+such situations, you will not want to clear C<$@> at all, but simply to
+append any new errors to any existing value of C<$@>.
+
+The G_KEEPERR flag is meant to be used in conjunction with G_EVAL in
+I<call_*> functions that are used to implement such code. This flag
+has no effect when G_EVAL is not used.
+
+When G_KEEPERR is used, any errors in the called code will be prefixed
+with the string "\t(in cleanup)", and appended to the current value
+of C<$@>. an error will not be appended if that same error string is
+already at the end of C<$@>.
+
+In addition, a warning is generated using the appended string. This can be
+disabled using C<no warnings 'misc'>.
+
+The G_KEEPERR flag was introduced in Perl version 5.002.
+
+See I<Using G_KEEPERR> for an example of a situation that warrants the
+use of this flag.
+
+=head2 Determining the Context
+
+As mentioned above, you can determine the context of the currently
+executing subroutine in Perl with I<wantarray>. The equivalent test
+can be made in C by using the C<GIMME_V> macro, which returns
+C<G_ARRAY> if you have been called in a list context, C<G_SCALAR> if
+in a scalar context, or C<G_VOID> if in a void context (i.e. the
+return value will not be used). An older version of this macro is
+called C<GIMME>; in a void context it returns C<G_SCALAR> instead of
+C<G_VOID>. An example of using the C<GIMME_V> macro is shown in
+section I<Using GIMME_V>.
+
+=head1 EXAMPLES
+
+Enough of the definition talk, let's have a few examples.
+
+Perl provides many macros to assist in accessing the Perl stack.
+Wherever possible, these macros should always be used when interfacing
+to Perl internals. We hope this should make the code less vulnerable
+to any changes made to Perl in the future.
+
+Another point worth noting is that in the first series of examples I
+have made use of only the I<call_pv> function. This has been done
+to keep the code simpler and ease you into the topic. Wherever
+possible, if the choice is between using I<call_pv> and
+I<call_sv>, you should always try to use I<call_sv>. See
+I<Using call_sv> for details.
+
+=head2 No Parameters, Nothing returned
+
+This first trivial example will call a Perl subroutine, I<PrintUID>, to
+print out the UID of the process.
+
+ sub PrintUID
+ {
+ print "UID is $<\n";
+ }
+
+and here is a C function to call it
+
+ static void
+ call_PrintUID()
+ {
+ dSP;
+
+ PUSHMARK(SP);
+ call_pv("PrintUID", G_DISCARD|G_NOARGS);
+ }
+
+Simple, eh.
+
+A few points to note about this example.
+
+=over 5
+
+=item 1.
+
+Ignore C<dSP> and C<PUSHMARK(SP)> for now. They will be discussed in
+the next example.
+
+=item 2.
+
+We aren't passing any parameters to I<PrintUID> so G_NOARGS can be
+specified.
+
+=item 3.
+
+We aren't interested in anything returned from I<PrintUID>, so
+G_DISCARD is specified. Even if I<PrintUID> was changed to
+return some value(s), having specified G_DISCARD will mean that they
+will be wiped by the time control returns from I<call_pv>.
+
+=item 4.
+
+As I<call_pv> is being used, the Perl subroutine is specified as a
+C string. In this case the subroutine name has been 'hard-wired' into the
+code.
+
+=item 5.
+
+Because we specified G_DISCARD, it is not necessary to check the value
+returned from I<call_pv>. It will always be 0.
+
+=back
+
+=head2 Passing Parameters
+
+Now let's make a slightly more complex example. This time we want to
+call a Perl subroutine, C<LeftString>, which will take 2 parameters--a
+string ($s) and an integer ($n). The subroutine will simply
+print the first $n characters of the string.
+
+So the Perl subroutine would look like this
+
+ sub LeftString
+ {
+ my($s, $n) = @_;
+ print substr($s, 0, $n), "\n";
+ }
+
+The C function required to call I<LeftString> would look like this.
+
+ static void
+ call_LeftString(a, b)
+ char * a;
+ int b;
+ {
+ dSP;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSVpv(a, 0)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ call_pv("LeftString", G_DISCARD);
+
+ FREETMPS;
+ LEAVE;
+ }
+
+Here are a few notes on the C function I<call_LeftString>.
+
+=over 5
+
+=item 1.
+
+Parameters are passed to the Perl subroutine using the Perl stack.
+This is the purpose of the code beginning with the line C<dSP> and
+ending with the line C<PUTBACK>. The C<dSP> declares a local copy
+of the stack pointer. This local copy should B<always> be accessed
+as C<SP>.
+
+=item 2.
+
+If you are going to put something onto the Perl stack, you need to know
+where to put it. This is the purpose of the macro C<dSP>--it declares
+and initializes a I<local> copy of the Perl stack pointer.
+
+All the other macros which will be used in this example require you to
+have used this macro.
+
+The exception to this rule is if you are calling a Perl subroutine
+directly from an XSUB function. In this case it is not necessary to
+use the C<dSP> macro explicitly--it will be declared for you
+automatically.
+
+=item 3.
+
+Any parameters to be pushed onto the stack should be bracketed by the
+C<PUSHMARK> and C<PUTBACK> macros. The purpose of these two macros, in
+this context, is to count the number of parameters you are
+pushing automatically. Then whenever Perl is creating the C<@_> array for the
+subroutine, it knows how big to make it.
+
+The C<PUSHMARK> macro tells Perl to make a mental note of the current
+stack pointer. Even if you aren't passing any parameters (like the
+example shown in the section I<No Parameters, Nothing returned>) you
+must still call the C<PUSHMARK> macro before you can call any of the
+I<call_*> functions--Perl still needs to know that there are no
+parameters.
+
+The C<PUTBACK> macro sets the global copy of the stack pointer to be
+the same as our local copy. If we didn't do this I<call_pv>
+wouldn't know where the two parameters we pushed were--remember that
+up to now all the stack pointer manipulation we have done is with our
+local copy, I<not> the global copy.
+
+=item 4.
+
+Next, we come to XPUSHs. This is where the parameters actually get
+pushed onto the stack. In this case we are pushing a string and an
+integer.
+
+See L<perlguts/"XSUBs and the Argument Stack"> for details
+on how the XPUSH macros work.
+
+=item 5.
+
+Because we created temporary values (by means of sv_2mortal() calls)
+we will have to tidy up the Perl stack and dispose of mortal SVs.
+
+This is the purpose of
+
+ ENTER;
+ SAVETMPS;
+
+at the start of the function, and
+
+ FREETMPS;
+ LEAVE;
+
+at the end. The C<ENTER>/C<SAVETMPS> pair creates a boundary for any
+temporaries we create. This means that the temporaries we get rid of
+will be limited to those which were created after these calls.
+
+The C<FREETMPS>/C<LEAVE> pair will get rid of any values returned by
+the Perl subroutine (see next example), plus it will also dump the
+mortal SVs we have created. Having C<ENTER>/C<SAVETMPS> at the
+beginning of the code makes sure that no other mortals are destroyed.
+
+Think of these macros as working a bit like using C<{> and C<}> in Perl
+to limit the scope of local variables.
+
+See the section I<Using Perl to dispose of temporaries> for details of
+an alternative to using these macros.
+
+=item 6.
+
+Finally, I<LeftString> can now be called via the I<call_pv> function.
+The only flag specified this time is G_DISCARD. Because we are passing
+2 parameters to the Perl subroutine this time, we have not specified
+G_NOARGS.
+
+=back
+
+=head2 Returning a Scalar
+
+Now for an example of dealing with the items returned from a Perl
+subroutine.
+
+Here is a Perl subroutine, I<Adder>, that takes 2 integer parameters
+and simply returns their sum.
+
+ sub Adder
+ {
+ my($a, $b) = @_;
+ $a + $b;
+ }
+
+Because we are now concerned with the return value from I<Adder>, the C
+function required to call it is now a bit more complex.
+
+ static void
+ call_Adder(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ int count;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(a)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ count = call_pv("Adder", G_SCALAR);
+
+ SPAGAIN;
+
+ if (count != 1)
+ croak("Big trouble\n");
+
+ printf ("The sum of %d and %d is %d\n", a, b, POPi);
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+ }
+
+Points to note this time are
+
+=over 5
+
+=item 1.
+
+The only flag specified this time was G_SCALAR. That means the C<@_>
+array will be created and that the value returned by I<Adder> will
+still exist after the call to I<call_pv>.
+
+=item 2.
+
+The purpose of the macro C<SPAGAIN> is to refresh the local copy of the
+stack pointer. This is necessary because it is possible that the memory
+allocated to the Perl stack has been reallocated whilst in the
+I<call_pv> call.
+
+If you are making use of the Perl stack pointer in your code you must
+always refresh the local copy using SPAGAIN whenever you make use
+of the I<call_*> functions or any other Perl internal function.
+
+=item 3.
+
+Although only a single value was expected to be returned from I<Adder>,
+it is still good practice to check the return code from I<call_pv>
+anyway.
+
+Expecting a single value is not quite the same as knowing that there
+will be one. If someone modified I<Adder> to return a list and we
+didn't check for that possibility and take appropriate action the Perl
+stack would end up in an inconsistent state. That is something you
+I<really> don't want to happen ever.
+
+=item 4.
+
+The C<POPi> macro is used here to pop the return value from the stack.
+In this case we wanted an integer, so C<POPi> was used.
+
+
+Here is the complete list of POP macros available, along with the types
+they return.
+
+ POPs SV
+ POPp pointer
+ POPn double
+ POPi integer
+ POPl long
+
+=item 5.
+
+The final C<PUTBACK> is used to leave the Perl stack in a consistent
+state before exiting the function. This is necessary because when we
+popped the return value from the stack with C<POPi> it updated only our
+local copy of the stack pointer. Remember, C<PUTBACK> sets the global
+stack pointer to be the same as our local copy.
+
+=back
+
+
+=head2 Returning a list of values
+
+Now, let's extend the previous example to return both the sum of the
+parameters and the difference.
+
+Here is the Perl subroutine
+
+ sub AddSubtract
+ {
+ my($a, $b) = @_;
+ ($a+$b, $a-$b);
+ }
+
+and this is the C function
+
+ static void
+ call_AddSubtract(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ int count;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(a)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ count = call_pv("AddSubtract", G_ARRAY);
+
+ SPAGAIN;
+
+ if (count != 2)
+ croak("Big trouble\n");
+
+ printf ("%d - %d = %d\n", a, b, POPi);
+ printf ("%d + %d = %d\n", a, b, POPi);
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+ }
+
+If I<call_AddSubtract> is called like this
+
+ call_AddSubtract(7, 4);
+
+then here is the output
+
+ 7 - 4 = 3
+ 7 + 4 = 11
+
+Notes
+
+=over 5
+
+=item 1.
+
+We wanted list context, so G_ARRAY was used.
+
+=item 2.
+
+Not surprisingly C<POPi> is used twice this time because we were
+retrieving 2 values from the stack. The important thing to note is that
+when using the C<POP*> macros they come off the stack in I<reverse>
+order.
+
+=back
+
+=head2 Returning a list in a scalar context
+
+Say the Perl subroutine in the previous section was called in a scalar
+context, like this
+
+ static void
+ call_AddSubScalar(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ int count;
+ int i;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(a)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ count = call_pv("AddSubtract", G_SCALAR);
+
+ SPAGAIN;
+
+ printf ("Items Returned = %d\n", count);
+
+ for (i = 1; i <= count; ++i)
+ printf ("Value %d = %d\n", i, POPi);
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+ }
+
+The other modification made is that I<call_AddSubScalar> will print the
+number of items returned from the Perl subroutine and their value (for
+simplicity it assumes that they are integer). So if
+I<call_AddSubScalar> is called
+
+ call_AddSubScalar(7, 4);
+
+then the output will be
+
+ Items Returned = 1
+ Value 1 = 3
+
+In this case the main point to note is that only the last item in the
+list is returned from the subroutine, I<AddSubtract> actually made it back to
+I<call_AddSubScalar>.
+
+
+=head2 Returning Data from Perl via the parameter list
+
+It is also possible to return values directly via the parameter list -
+whether it is actually desirable to do it is another matter entirely.
+
+The Perl subroutine, I<Inc>, below takes 2 parameters and increments
+each directly.
+
+ sub Inc
+ {
+ ++ $_[0];
+ ++ $_[1];
+ }
+
+and here is a C function to call it.
+
+ static void
+ call_Inc(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ int count;
+ SV * sva;
+ SV * svb;
+
+ ENTER;
+ SAVETMPS;
+
+ sva = sv_2mortal(newSViv(a));
+ svb = sv_2mortal(newSViv(b));
+
+ PUSHMARK(SP);
+ XPUSHs(sva);
+ XPUSHs(svb);
+ PUTBACK;
+
+ count = call_pv("Inc", G_DISCARD);
+
+ if (count != 0)
+ croak ("call_Inc: expected 0 values from 'Inc', got %d\n",
+ count);
+
+ printf ("%d + 1 = %d\n", a, SvIV(sva));
+ printf ("%d + 1 = %d\n", b, SvIV(svb));
+
+ FREETMPS;
+ LEAVE;
+ }
+
+To be able to access the two parameters that were pushed onto the stack
+after they return from I<call_pv> it is necessary to make a note
+of their addresses--thus the two variables C<sva> and C<svb>.
+
+The reason this is necessary is that the area of the Perl stack which
+held them will very likely have been overwritten by something else by
+the time control returns from I<call_pv>.
+
+
+
+
+=head2 Using G_EVAL
+
+Now an example using G_EVAL. Below is a Perl subroutine which computes
+the difference of its 2 parameters. If this would result in a negative
+result, the subroutine calls I<die>.
+
+ sub Subtract
+ {
+ my ($a, $b) = @_;
+
+ die "death can be fatal\n" if $a < $b;
+
+ $a - $b;
+ }
+
+and some C to call it
+
+ static void
+ call_Subtract(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ int count;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(a)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ count = call_pv("Subtract", G_EVAL|G_SCALAR);
+
+ SPAGAIN;
+
+ /* Check the eval first */
+ if (SvTRUE(ERRSV))
+ {
+ printf ("Uh oh - %s\n", SvPV_nolen(ERRSV));
+ POPs;
+ }
+ else
+ {
+ if (count != 1)
+ croak("call_Subtract: wanted 1 value from 'Subtract', got %d\n",
+ count);
+
+ printf ("%d - %d = %d\n", a, b, POPi);
+ }
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+ }
+
+If I<call_Subtract> is called thus
+
+ call_Subtract(4, 5)
+
+the following will be printed
+
+ Uh oh - death can be fatal
+
+Notes
+
+=over 5
+
+=item 1.
+
+We want to be able to catch the I<die> so we have used the G_EVAL
+flag. Not specifying this flag would mean that the program would
+terminate immediately at the I<die> statement in the subroutine
+I<Subtract>.
+
+=item 2.
+
+The code
+
+ if (SvTRUE(ERRSV))
+ {
+ printf ("Uh oh - %s\n", SvPV_nolen(ERRSV));
+ POPs;
+ }
+
+is the direct equivalent of this bit of Perl
+
+ print "Uh oh - $@\n" if $@;
+
+C<PL_errgv> is a perl global of type C<GV *> that points to the
+symbol table entry containing the error. C<ERRSV> therefore
+refers to the C equivalent of C<$@>.
+
+=item 3.
+
+Note that the stack is popped using C<POPs> in the block where
+C<SvTRUE(ERRSV)> is true. This is necessary because whenever a
+I<call_*> function invoked with G_EVAL|G_SCALAR returns an error,
+the top of the stack holds the value I<undef>. Because we want the
+program to continue after detecting this error, it is essential that
+the stack is tidied up by removing the I<undef>.
+
+=back
+
+
+=head2 Using G_KEEPERR
+
+Consider this rather facetious example, where we have used an XS
+version of the call_Subtract example above inside a destructor:
+
+ package Foo;
+ sub new { bless {}, $_[0] }
+ sub Subtract {
+ my($a,$b) = @_;
+ die "death can be fatal" if $a < $b;
+ $a - $b;
+ }
+ sub DESTROY { call_Subtract(5, 4); }
+ sub foo { die "foo dies"; }
+
+ package main;
+ eval { Foo->new->foo };
+ print "Saw: $@" if $@; # should be, but isn't
+
+This example will fail to recognize that an error occurred inside the
+C<eval {}>. Here's why: the call_Subtract code got executed while perl
+was cleaning up temporaries when exiting the eval block, and because
+call_Subtract is implemented with I<call_pv> using the G_EVAL
+flag, it promptly reset C<$@>. This results in the failure of the
+outermost test for C<$@>, and thereby the failure of the error trap.
+
+Appending the G_KEEPERR flag, so that the I<call_pv> call in
+call_Subtract reads:
+
+ count = call_pv("Subtract", G_EVAL|G_SCALAR|G_KEEPERR);
+
+will preserve the error and restore reliable error handling.
+
+=head2 Using call_sv
+
+In all the previous examples I have 'hard-wired' the name of the Perl
+subroutine to be called from C. Most of the time though, it is more
+convenient to be able to specify the name of the Perl subroutine from
+within the Perl script.
+
+Consider the Perl code below
+
+ sub fred
+ {
+ print "Hello there\n";
+ }
+
+ CallSubPV("fred");
+
+Here is a snippet of XSUB which defines I<CallSubPV>.
+
+ void
+ CallSubPV(name)
+ char * name
+ CODE:
+ PUSHMARK(SP);
+ call_pv(name, G_DISCARD|G_NOARGS);
+
+That is fine as far as it goes. The thing is, the Perl subroutine
+can be specified as only a string. For Perl 4 this was adequate,
+but Perl 5 allows references to subroutines and anonymous subroutines.
+This is where I<call_sv> is useful.
+
+The code below for I<CallSubSV> is identical to I<CallSubPV> except
+that the C<name> parameter is now defined as an SV* and we use
+I<call_sv> instead of I<call_pv>.
+
+ void
+ CallSubSV(name)
+ SV * name
+ CODE:
+ PUSHMARK(SP);
+ call_sv(name, G_DISCARD|G_NOARGS);
+
+Because we are using an SV to call I<fred> the following can all be used
+
+ CallSubSV("fred");
+ CallSubSV(\&fred);
+ $ref = \&fred;
+ CallSubSV($ref);
+ CallSubSV( sub { print "Hello there\n" } );
+
+As you can see, I<call_sv> gives you much greater flexibility in
+how you can specify the Perl subroutine.
+
+You should note that if it is necessary to store the SV (C<name> in the
+example above) which corresponds to the Perl subroutine so that it can
+be used later in the program, it not enough just to store a copy of the
+pointer to the SV. Say the code above had been like this
+
+ static SV * rememberSub;
+
+ void
+ SaveSub1(name)
+ SV * name
+ CODE:
+ rememberSub = name;
+
+ void
+ CallSavedSub1()
+ CODE:
+ PUSHMARK(SP);
+ call_sv(rememberSub, G_DISCARD|G_NOARGS);
+
+The reason this is wrong is that by the time you come to use the
+pointer C<rememberSub> in C<CallSavedSub1>, it may or may not still refer
+to the Perl subroutine that was recorded in C<SaveSub1>. This is
+particularly true for these cases
+
+ SaveSub1(\&fred);
+ CallSavedSub1();
+
+ SaveSub1( sub { print "Hello there\n" } );
+ CallSavedSub1();
+
+By the time each of the C<SaveSub1> statements above have been executed,
+the SV*s which corresponded to the parameters will no longer exist.
+Expect an error message from Perl of the form
+
+ Can't use an undefined value as a subroutine reference at ...
+
+for each of the C<CallSavedSub1> lines.
+
+Similarly, with this code
+
+ $ref = \&fred;
+ SaveSub1($ref);
+ $ref = 47;
+ CallSavedSub1();
+
+you can expect one of these messages (which you actually get is dependent on
+the version of Perl you are using)
+
+ Not a CODE reference at ...
+ Undefined subroutine &main::47 called ...
+
+The variable $ref may have referred to the subroutine C<fred>
+whenever the call to C<SaveSub1> was made but by the time
+C<CallSavedSub1> gets called it now holds the number C<47>. Because we
+saved only a pointer to the original SV in C<SaveSub1>, any changes to
+$ref will be tracked by the pointer C<rememberSub>. This means that
+whenever C<CallSavedSub1> gets called, it will attempt to execute the
+code which is referenced by the SV* C<rememberSub>. In this case
+though, it now refers to the integer C<47>, so expect Perl to complain
+loudly.
+
+A similar but more subtle problem is illustrated with this code
+
+ $ref = \&fred;
+ SaveSub1($ref);
+ $ref = \&joe;
+ CallSavedSub1();
+
+This time whenever C<CallSavedSub1> get called it will execute the Perl
+subroutine C<joe> (assuming it exists) rather than C<fred> as was
+originally requested in the call to C<SaveSub1>.
+
+To get around these problems it is necessary to take a full copy of the
+SV. The code below shows C<SaveSub2> modified to do that
+
+ static SV * keepSub = (SV*)NULL;
+
+ void
+ SaveSub2(name)
+ SV * name
+ CODE:
+ /* Take a copy of the callback */
+ if (keepSub == (SV*)NULL)
+ /* First time, so create a new SV */
+ keepSub = newSVsv(name);
+ else
+ /* Been here before, so overwrite */
+ SvSetSV(keepSub, name);
+
+ void
+ CallSavedSub2()
+ CODE:
+ PUSHMARK(SP);
+ call_sv(keepSub, G_DISCARD|G_NOARGS);
+
+To avoid creating a new SV every time C<SaveSub2> is called,
+the function first checks to see if it has been called before. If not,
+then space for a new SV is allocated and the reference to the Perl
+subroutine, C<name> is copied to the variable C<keepSub> in one
+operation using C<newSVsv>. Thereafter, whenever C<SaveSub2> is called
+the existing SV, C<keepSub>, is overwritten with the new value using
+C<SvSetSV>.
+
+=head2 Using call_argv
+
+Here is a Perl subroutine which prints whatever parameters are passed
+to it.
+
+ sub PrintList
+ {
+ my(@list) = @_;
+
+ foreach (@list) { print "$_\n" }
+ }
+
+and here is an example of I<call_argv> which will call
+I<PrintList>.
+
+ static char * words[] = {"alpha", "beta", "gamma", "delta", NULL};
+
+ static void
+ call_PrintList()
+ {
+ dSP;
+
+ call_argv("PrintList", G_DISCARD, words);
+ }
+
+Note that it is not necessary to call C<PUSHMARK> in this instance.
+This is because I<call_argv> will do it for you.
+
+=head2 Using call_method
+
+Consider the following Perl code
+
+ {
+ package Mine;
+
+ sub new
+ {
+ my($type) = shift;
+ bless [@_]
+ }
+
+ sub Display
+ {
+ my ($self, $index) = @_;
+ print "$index: $$self[$index]\n";
+ }
+
+ sub PrintID
+ {
+ my($class) = @_;
+ print "This is Class $class version 1.0\n";
+ }
+ }
+
+It implements just a very simple class to manage an array. Apart from
+the constructor, C<new>, it declares methods, one static and one
+virtual. The static method, C<PrintID>, prints out simply the class
+name and a version number. The virtual method, C<Display>, prints out a
+single element of the array. Here is an all Perl example of using it.
+
+ $a = Mine->new('red', 'green', 'blue');
+ $a->Display(1);
+ Mine->PrintID;
+
+will print
+
+ 1: green
+ This is Class Mine version 1.0
+
+Calling a Perl method from C is fairly straightforward. The following
+things are required
+
+=over 5
+
+=item *
+
+a reference to the object for a virtual method or the name of the class
+for a static method.
+
+=item *
+
+the name of the method.
+
+=item *
+
+any other parameters specific to the method.
+
+=back
+
+Here is a simple XSUB which illustrates the mechanics of calling both
+the C<PrintID> and C<Display> methods from C.
+
+ void
+ call_Method(ref, method, index)
+ SV * ref
+ char * method
+ int index
+ CODE:
+ PUSHMARK(SP);
+ XPUSHs(ref);
+ XPUSHs(sv_2mortal(newSViv(index)));
+ PUTBACK;
+
+ call_method(method, G_DISCARD);
+
+ void
+ call_PrintID(class, method)
+ char * class
+ char * method
+ CODE:
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSVpv(class, 0)));
+ PUTBACK;
+
+ call_method(method, G_DISCARD);
+
+
+So the methods C<PrintID> and C<Display> can be invoked like this
+
+ $a = Mine->new('red', 'green', 'blue');
+ call_Method($a, 'Display', 1);
+ call_PrintID('Mine', 'PrintID');
+
+The only thing to note is that in both the static and virtual methods,
+the method name is not passed via the stack--it is used as the first
+parameter to I<call_method>.
+
+=head2 Using GIMME_V
+
+Here is a trivial XSUB which prints the context in which it is
+currently executing.
+
+ void
+ PrintContext()
+ CODE:
+ I32 gimme = GIMME_V;
+ if (gimme == G_VOID)
+ printf ("Context is Void\n");
+ else if (gimme == G_SCALAR)
+ printf ("Context is Scalar\n");
+ else
+ printf ("Context is Array\n");
+
+and here is some Perl to test it
+
+ PrintContext;
+ $a = PrintContext;
+ @a = PrintContext;
+
+The output from that will be
+
+ Context is Void
+ Context is Scalar
+ Context is Array
+
+=head2 Using Perl to dispose of temporaries
+
+In the examples given to date, any temporaries created in the callback
+(i.e., parameters passed on the stack to the I<call_*> function or
+values returned via the stack) have been freed by one of these methods
+
+=over 5
+
+=item *
+
+specifying the G_DISCARD flag with I<call_*>.
+
+=item *
+
+explicitly disposed of using the C<ENTER>/C<SAVETMPS> -
+C<FREETMPS>/C<LEAVE> pairing.
+
+=back
+
+There is another method which can be used, namely letting Perl do it
+for you automatically whenever it regains control after the callback
+has terminated. This is done by simply not using the
+
+ ENTER;
+ SAVETMPS;
+ ...
+ FREETMPS;
+ LEAVE;
+
+sequence in the callback (and not, of course, specifying the G_DISCARD
+flag).
+
+If you are going to use this method you have to be aware of a possible
+memory leak which can arise under very specific circumstances. To
+explain these circumstances you need to know a bit about the flow of
+control between Perl and the callback routine.
+
+The examples given at the start of the document (an error handler and
+an event driven program) are typical of the two main sorts of flow
+control that you are likely to encounter with callbacks. There is a
+very important distinction between them, so pay attention.
+
+In the first example, an error handler, the flow of control could be as
+follows. You have created an interface to an external library.
+Control can reach the external library like this
+
+ perl --> XSUB --> external library
+
+Whilst control is in the library, an error condition occurs. You have
+previously set up a Perl callback to handle this situation, so it will
+get executed. Once the callback has finished, control will drop back to
+Perl again. Here is what the flow of control will be like in that
+situation
+
+ perl --> XSUB --> external library
+ ...
+ error occurs
+ ...
+ external library --> call_* --> perl
+ |
+ perl <-- XSUB <-- external library <-- call_* <----+
+
+After processing of the error using I<call_*> is completed,
+control reverts back to Perl more or less immediately.
+
+In the diagram, the further right you go the more deeply nested the
+scope is. It is only when control is back with perl on the extreme
+left of the diagram that you will have dropped back to the enclosing
+scope and any temporaries you have left hanging around will be freed.
+
+In the second example, an event driven program, the flow of control
+will be more like this
+
+ perl --> XSUB --> event handler
+ ...
+ event handler --> call_* --> perl
+ |
+ event handler <-- call_* <----+
+ ...
+ event handler --> call_* --> perl
+ |
+ event handler <-- call_* <----+
+ ...
+ event handler --> call_* --> perl
+ |
+ event handler <-- call_* <----+
+
+In this case the flow of control can consist of only the repeated
+sequence
+
+ event handler --> call_* --> perl
+
+for practically the complete duration of the program. This means that
+control may I<never> drop back to the surrounding scope in Perl at the
+extreme left.
+
+So what is the big problem? Well, if you are expecting Perl to tidy up
+those temporaries for you, you might be in for a long wait. For Perl
+to dispose of your temporaries, control must drop back to the
+enclosing scope at some stage. In the event driven scenario that may
+never happen. This means that as time goes on, your program will
+create more and more temporaries, none of which will ever be freed. As
+each of these temporaries consumes some memory your program will
+eventually consume all the available memory in your system--kapow!
+
+So here is the bottom line--if you are sure that control will revert
+back to the enclosing Perl scope fairly quickly after the end of your
+callback, then it isn't absolutely necessary to dispose explicitly of
+any temporaries you may have created. Mind you, if you are at all
+uncertain about what to do, it doesn't do any harm to tidy up anyway.
+
+
+=head2 Strategies for storing Callback Context Information
+
+
+Potentially one of the trickiest problems to overcome when designing a
+callback interface can be figuring out how to store the mapping between
+the C callback function and the Perl equivalent.
+
+To help understand why this can be a real problem first consider how a
+callback is set up in an all C environment. Typically a C API will
+provide a function to register a callback. This will expect a pointer
+to a function as one of its parameters. Below is a call to a
+hypothetical function C<register_fatal> which registers the C function
+to get called when a fatal error occurs.
+
+ register_fatal(cb1);
+
+The single parameter C<cb1> is a pointer to a function, so you must
+have defined C<cb1> in your code, say something like this
+
+ static void
+ cb1()
+ {
+ printf ("Fatal Error\n");
+ exit(1);
+ }
+
+Now change that to call a Perl subroutine instead
+
+ static SV * callback = (SV*)NULL;
+
+ static void
+ cb1()
+ {
+ dSP;
+
+ PUSHMARK(SP);
+
+ /* Call the Perl sub to process the callback */
+ call_sv(callback, G_DISCARD);
+ }
+
+
+ void
+ register_fatal(fn)
+ SV * fn
+ CODE:
+ /* Remember the Perl sub */
+ if (callback == (SV*)NULL)
+ callback = newSVsv(fn);
+ else
+ SvSetSV(callback, fn);
+
+ /* register the callback with the external library */
+ register_fatal(cb1);
+
+where the Perl equivalent of C<register_fatal> and the callback it
+registers, C<pcb1>, might look like this
+
+ # Register the sub pcb1
+ register_fatal(\&pcb1);
+
+ sub pcb1
+ {
+ die "I'm dying...\n";
+ }
+
+The mapping between the C callback and the Perl equivalent is stored in
+the global variable C<callback>.
+
+This will be adequate if you ever need to have only one callback
+registered at any time. An example could be an error handler like the
+code sketched out above. Remember though, repeated calls to
+C<register_fatal> will replace the previously registered callback
+function with the new one.
+
+Say for example you want to interface to a library which allows asynchronous
+file i/o. In this case you may be able to register a callback whenever
+a read operation has completed. To be of any use we want to be able to
+call separate Perl subroutines for each file that is opened. As it
+stands, the error handler example above would not be adequate as it
+allows only a single callback to be defined at any time. What we
+require is a means of storing the mapping between the opened file and
+the Perl subroutine we want to be called for that file.
+
+Say the i/o library has a function C<asynch_read> which associates a C
+function C<ProcessRead> with a file handle C<fh>--this assumes that it
+has also provided some routine to open the file and so obtain the file
+handle.
+
+ asynch_read(fh, ProcessRead)
+
+This may expect the C I<ProcessRead> function of this form
+
+ void
+ ProcessRead(fh, buffer)
+ int fh;
+ char * buffer;
+ {
+ ...
+ }
+
+To provide a Perl interface to this library we need to be able to map
+between the C<fh> parameter and the Perl subroutine we want called. A
+hash is a convenient mechanism for storing this mapping. The code
+below shows a possible implementation
+
+ static HV * Mapping = (HV*)NULL;
+
+ void
+ asynch_read(fh, callback)
+ int fh
+ SV * callback
+ CODE:
+ /* If the hash doesn't already exist, create it */
+ if (Mapping == (HV*)NULL)
+ Mapping = newHV();
+
+ /* Save the fh -> callback mapping */
+ hv_store(Mapping, (char*)&fh, sizeof(fh), newSVsv(callback), 0);
+
+ /* Register with the C Library */
+ asynch_read(fh, asynch_read_if);
+
+and C<asynch_read_if> could look like this
+
+ static void
+ asynch_read_if(fh, buffer)
+ int fh;
+ char * buffer;
+ {
+ dSP;
+ SV ** sv;
+
+ /* Get the callback associated with fh */
+ sv = hv_fetch(Mapping, (char*)&fh , sizeof(fh), FALSE);
+ if (sv == (SV**)NULL)
+ croak("Internal error...\n");
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(fh)));
+ XPUSHs(sv_2mortal(newSVpv(buffer, 0)));
+ PUTBACK;
+
+ /* Call the Perl sub */
+ call_sv(*sv, G_DISCARD);
+ }
+
+For completeness, here is C<asynch_close>. This shows how to remove
+the entry from the hash C<Mapping>.
+
+ void
+ asynch_close(fh)
+ int fh
+ CODE:
+ /* Remove the entry from the hash */
+ (void) hv_delete(Mapping, (char*)&fh, sizeof(fh), G_DISCARD);
+
+ /* Now call the real asynch_close */
+ asynch_close(fh);
+
+So the Perl interface would look like this
+
+ sub callback1
+ {
+ my($handle, $buffer) = @_;
+ }
+
+ # Register the Perl callback
+ asynch_read($fh, \&callback1);
+
+ asynch_close($fh);
+
+The mapping between the C callback and Perl is stored in the global
+hash C<Mapping> this time. Using a hash has the distinct advantage that
+it allows an unlimited number of callbacks to be registered.
+
+What if the interface provided by the C callback doesn't contain a
+parameter which allows the file handle to Perl subroutine mapping? Say
+in the asynchronous i/o package, the callback function gets passed only
+the C<buffer> parameter like this
+
+ void
+ ProcessRead(buffer)
+ char * buffer;
+ {
+ ...
+ }
+
+Without the file handle there is no straightforward way to map from the
+C callback to the Perl subroutine.
+
+In this case a possible way around this problem is to predefine a
+series of C functions to act as the interface to Perl, thus
+
+ #define MAX_CB 3
+ #define NULL_HANDLE -1
+ typedef void (*FnMap)();
+
+ struct MapStruct {
+ FnMap Function;
+ SV * PerlSub;
+ int Handle;
+ };
+
+ static void fn1();
+ static void fn2();
+ static void fn3();
+
+ static struct MapStruct Map [MAX_CB] =
+ {
+ { fn1, NULL, NULL_HANDLE },
+ { fn2, NULL, NULL_HANDLE },
+ { fn3, NULL, NULL_HANDLE }
+ };
+
+ static void
+ Pcb(index, buffer)
+ int index;
+ char * buffer;
+ {
+ dSP;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSVpv(buffer, 0)));
+ PUTBACK;
+
+ /* Call the Perl sub */
+ call_sv(Map[index].PerlSub, G_DISCARD);
+ }
+
+ static void
+ fn1(buffer)
+ char * buffer;
+ {
+ Pcb(0, buffer);
+ }
+
+ static void
+ fn2(buffer)
+ char * buffer;
+ {
+ Pcb(1, buffer);
+ }
+
+ static void
+ fn3(buffer)
+ char * buffer;
+ {
+ Pcb(2, buffer);
+ }
+
+ void
+ array_asynch_read(fh, callback)
+ int fh
+ SV * callback
+ CODE:
+ int index;
+ int null_index = MAX_CB;
+
+ /* Find the same handle or an empty entry */
+ for (index = 0; index < MAX_CB; ++index)
+ {
+ if (Map[index].Handle == fh)
+ break;
+
+ if (Map[index].Handle == NULL_HANDLE)
+ null_index = index;
+ }
+
+ if (index == MAX_CB && null_index == MAX_CB)
+ croak ("Too many callback functions registered\n");
+
+ if (index == MAX_CB)
+ index = null_index;
+
+ /* Save the file handle */
+ Map[index].Handle = fh;
+
+ /* Remember the Perl sub */
+ if (Map[index].PerlSub == (SV*)NULL)
+ Map[index].PerlSub = newSVsv(callback);
+ else
+ SvSetSV(Map[index].PerlSub, callback);
+
+ asynch_read(fh, Map[index].Function);
+
+ void
+ array_asynch_close(fh)
+ int fh
+ CODE:
+ int index;
+
+ /* Find the file handle */
+ for (index = 0; index < MAX_CB; ++ index)
+ if (Map[index].Handle == fh)
+ break;
+
+ if (index == MAX_CB)
+ croak ("could not close fh %d\n", fh);
+
+ Map[index].Handle = NULL_HANDLE;
+ SvREFCNT_dec(Map[index].PerlSub);
+ Map[index].PerlSub = (SV*)NULL;
+
+ asynch_close(fh);
+
+In this case the functions C<fn1>, C<fn2>, and C<fn3> are used to
+remember the Perl subroutine to be called. Each of the functions holds
+a separate hard-wired index which is used in the function C<Pcb> to
+access the C<Map> array and actually call the Perl subroutine.
+
+There are some obvious disadvantages with this technique.
+
+Firstly, the code is considerably more complex than with the previous
+example.
+
+Secondly, there is a hard-wired limit (in this case 3) to the number of
+callbacks that can exist simultaneously. The only way to increase the
+limit is by modifying the code to add more functions and then
+recompiling. None the less, as long as the number of functions is
+chosen with some care, it is still a workable solution and in some
+cases is the only one available.
+
+To summarize, here are a number of possible methods for you to consider
+for storing the mapping between C and the Perl callback
+
+=over 5
+
+=item 1. Ignore the problem - Allow only 1 callback
+
+For a lot of situations, like interfacing to an error handler, this may
+be a perfectly adequate solution.
+
+=item 2. Create a sequence of callbacks - hard wired limit
+
+If it is impossible to tell from the parameters passed back from the C
+callback what the context is, then you may need to create a sequence of C
+callback interface functions, and store pointers to each in an array.
+
+=item 3. Use a parameter to map to the Perl callback
+
+A hash is an ideal mechanism to store the mapping between C and Perl.
+
+=back
+
+
+=head2 Alternate Stack Manipulation
+
+
+Although I have made use of only the C<POP*> macros to access values
+returned from Perl subroutines, it is also possible to bypass these
+macros and read the stack using the C<ST> macro (See L<perlxs> for a
+full description of the C<ST> macro).
+
+Most of the time the C<POP*> macros should be adequate, the main
+problem with them is that they force you to process the returned values
+in sequence. This may not be the most suitable way to process the
+values in some cases. What we want is to be able to access the stack in
+a random order. The C<ST> macro as used when coding an XSUB is ideal
+for this purpose.
+
+The code below is the example given in the section I<Returning a list
+of values> recoded to use C<ST> instead of C<POP*>.
+
+ static void
+ call_AddSubtract2(a, b)
+ int a;
+ int b;
+ {
+ dSP;
+ I32 ax;
+ int count;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHMARK(SP);
+ XPUSHs(sv_2mortal(newSViv(a)));
+ XPUSHs(sv_2mortal(newSViv(b)));
+ PUTBACK;
+
+ count = call_pv("AddSubtract", G_ARRAY);
+
+ SPAGAIN;
+ SP -= count;
+ ax = (SP - PL_stack_base) + 1;
+
+ if (count != 2)
+ croak("Big trouble\n");
+
+ printf ("%d + %d = %d\n", a, b, SvIV(ST(0)));
+ printf ("%d - %d = %d\n", a, b, SvIV(ST(1)));
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+ }
+
+Notes
+
+=over 5
+
+=item 1.
+
+Notice that it was necessary to define the variable C<ax>. This is
+because the C<ST> macro expects it to exist. If we were in an XSUB it
+would not be necessary to define C<ax> as it is already defined for
+you.
+
+=item 2.
+
+The code
+
+ SPAGAIN;
+ SP -= count;
+ ax = (SP - PL_stack_base) + 1;
+
+sets the stack up so that we can use the C<ST> macro.
+
+=item 3.
+
+Unlike the original coding of this example, the returned
+values are not accessed in reverse order. So C<ST(0)> refers to the
+first value returned by the Perl subroutine and C<ST(count-1)>
+refers to the last.
+
+=back
+
+=head2 Creating and calling an anonymous subroutine in C
+
+As we've already shown, C<call_sv> can be used to invoke an
+anonymous subroutine. However, our example showed a Perl script
+invoking an XSUB to perform this operation. Let's see how it can be
+done inside our C code:
+
+ ...
+
+ SV *cvrv = eval_pv("sub { print 'You will not find me cluttering any namespace!' }", TRUE);
+
+ ...
+
+ call_sv(cvrv, G_VOID|G_NOARGS);
+
+C<eval_pv> is used to compile the anonymous subroutine, which
+will be the return value as well (read more about C<eval_pv> in
+L<perlapi/eval_pv>). Once this code reference is in hand, it
+can be mixed in with all the previous examples we've shown.
+
+=head1 LIGHTWEIGHT CALLBACKS
+
+Sometimes you need to invoke the same subroutine repeatedly.
+This usually happens with a function that acts on a list of
+values, such as Perl's built-in sort(). You can pass a
+comparison function to sort(), which will then be invoked
+for every pair of values that needs to be compared. The first()
+and reduce() functions from L<List::Util> follow a similar
+pattern.
+
+In this case it is possible to speed up the routine (often
+quite substantially) by using the lightweight callback API.
+The idea is that the calling context only needs to be
+created and destroyed once, and the sub can be called
+arbitrarily many times in between.
+
+It is usual to pass parameters using global variables (typically
+$_ for one parameter, or $a and $b for two parameters) rather
+than via @_. (It is possible to use the @_ mechanism if you know
+what you're doing, though there is as yet no supported API for
+it. It's also inherently slower.)
+
+The pattern of macro calls is like this:
+
+ dMULTICALL; /* Declare local variables */
+ I32 gimme = G_SCALAR; /* context of the call: G_SCALAR,
+ * G_LIST, or G_VOID */
+
+ PUSH_MULTICALL(cv); /* Set up the context for calling cv,
+ and set local vars appropriately */
+
+ /* loop */ {
+ /* set the value(s) af your parameter variables */
+ MULTICALL; /* Make the actual call */
+ } /* end of loop */
+
+ POP_MULTICALL; /* Tear down the calling context */
+
+For some concrete examples, see the implementation of the
+first() and reduce() functions of List::Util 1.18. There you
+will also find a header file that emulates the multicall API
+on older versions of perl.
+
+=head1 SEE ALSO
+
+L<perlxs>, L<perlguts>, L<perlembed>
+
+=head1 AUTHOR
+
+Paul Marquess
+
+Special thanks to the following people who assisted in the creation of
+the document.
+
+Jeff Okamoto, Tim Bunce, Nick Gianniotis, Steve Kelem, Gurusamy Sarathy
+and Larry Wall.
+
+=head1 DATE
+
+Version 1.3, 14th Apr 1997
diff --git a/Master/tlpkg/tlperl/lib/pods/perlce.pod b/Master/tlpkg/tlperl/lib/pods/perlce.pod
new file mode 100644
index 00000000000..25cef84af67
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlce.pod
@@ -0,0 +1,306 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+perlce - Perl for WinCE
+
+=head1 Building Perl for WinCE
+
+=head2 DESCRIPTION
+
+This file gives the instructions for building Perl5.8 and above for
+WinCE. Please read and understand the terms under which this
+software is distributed.
+
+=head2 General explanations on cross-compiling WinCE
+
+=over
+
+=item *
+
+C<miniperl> is built. This is a single executable (without DLL), intended
+to run on Win32, and it will facilitate remaining build process; all binaries
+built after it are foreign and should not run locally.
+
+C<miniperl> is built using C<./win32/Makefile>; this is part of normal
+build process invoked as dependency from wince/Makefile.ce
+
+=item *
+
+After C<miniperl> is built, C<configpm> is invoked to create right C<Config.pm>
+in right place and its corresponding Cross.pm.
+
+Unlike Win32 build, miniperl will not have C<Config.pm> of host within reach;
+it rather will use C<Config.pm> from within cross-compilation directories.
+
+File C<Cross.pm> is dead simple: for given cross-architecture places in @INC
+a path where perl modules are, and right C<Config.pm> in that place.
+
+That said, C<miniperl -Ilib -MConfig -we 1> should report an error, because
+it can not find C<Config.pm>. If it does not give an error -- wrong C<Config.pm>
+is substituted, and resulting binaries will be a mess.
+
+C<miniperl -MCross -MConfig -we 1> should run okay, and it will provide right
+C<Config.pm> for further compilations.
+
+=item *
+
+During extensions build phase, a script C<./win32/buldext.pl> is invoked,
+which in turn steps in C<./ext> subdirectories and performs a build of
+each extension in turn.
+
+All invokes of C<Makefile.PL> are provided with C<-MCross> so to enable cross-
+compile.
+
+=back
+
+=head2 BUILD
+
+This section describes the steps to be performed to build PerlCE.
+You may find additional information about building perl for WinCE
+at L<http://perlce.sourceforge.net> and some pre-built binaries.
+
+=head3 Tools & SDK
+
+For compiling, you need following:
+
+=over 4
+
+=item * Microsoft Embedded Visual Tools
+
+=item * Microsoft Visual C++
+
+=item * Rainer Keuchel's celib-sources
+
+=item * Rainer Keuchel's console-sources
+
+=back
+
+Needed source files can be downloaded at
+L<http://www.rainer-keuchel.de/wince/dirlist.html>
+
+=head3 Make
+
+Normally you only need to edit C<./win32/ce-helpers/compile.bat>
+to reflect your system and run it.
+
+File C<./win32/ce-helpers/compile.bat> is actually a wrapper to call
+C<nmake -f makefile.ce> with appropriate parameters and it accepts extra
+parameters and forwards them to C<nmake> command as additional
+arguments. You should pass target this way.
+
+To prepare distribution you need to do following:
+
+=over 4
+
+=item * go to C<./win32> subdirectory
+
+=item * edit file C<./win32/ce-helpers/compile.bat>
+
+=item * run
+ compile.bat
+
+=item * run
+ compile.bat dist
+
+=back
+
+C<Makefile.ce> has C<CROSS_NAME> macro, and it is used further to refer to
+your cross-compilation scheme. You could assign a name to it, but this
+is not necessary, because by default it is assigned after your machine
+configuration name, such as "wince-sh3-hpc-wce211", and this is enough
+to distinguish different builds at the same time. This option could be
+handy for several different builds on same platform to perform, say,
+threaded build. In a following example we assume that all required
+environment variables are set properly for C cross-compiler (a special
+*.bat file could fit perfectly to this purpose) and your C<compile.bat>
+has proper "MACHINE" parameter set, to, say, C<wince-mips-pocket-wce300>.
+
+ compile.bat
+ compile.bat dist
+ compile.bat CROSS_NAME=mips-wce300-thr "USE_ITHREADS=define" "USE_IMP_SYS=define" "USE_MULTI=define"
+ compile.bat CROSS_NAME=mips-wce300-thr "USE_ITHREADS=define" "USE_IMP_SYS=define" "USE_MULTI=define" dist
+
+If all goes okay and no errors during a build, you'll get two independent
+distributions: C<wince-mips-pocket-wce300> and C<mips-wce300-thr>.
+
+Target C<dist> prepares distribution file set. Target C<zipdist> performs
+same as C<dist> but additionally compresses distribution files into zip
+archive.
+
+NOTE: during a build there could be created a number (or one) of C<Config.pm>
+for cross-compilation ("foreign" C<Config.pm>) and those are hidden inside
+C<../xlib/$(CROSS_NAME)> with other auxilary files, but, and this is important to
+note, there should be B<no> C<Config.pm> for host miniperl.
+If you'll get an error that perl could not find Config.pm somewhere in building
+process this means something went wrong. Most probably you forgot to
+specify a cross-compilation when invoking miniperl.exe to Makefile.PL
+When building an extension for cross-compilation your command line should
+look like
+
+ ..\miniperl.exe -I..\lib -MCross=mips-wce300-thr Makefile.PL
+
+or just
+
+ ..\miniperl.exe -I..\lib -MCross Makefile.PL
+
+to refer a cross-compilation that was created last time.
+
+All questions related to building for WinCE devices could be asked in
+F<perlce-user@lists.sourceforge.net> mailing list.
+
+=head1 Using Perl on WinCE
+
+=head2 DESCRIPTION
+
+PerlCE is currently linked with a simple console window, so it also
+works on non-hpc devices.
+
+The simple stdio implementation creates the files C<stdin.txt>,
+C<stdout.txt> and C<stderr.txt>, so you might examine them if your
+console has only a liminted number of cols.
+
+When exitcode is non-zero, a message box appears, otherwise the
+console closes, so you might have to catch an exit with
+status 0 in your program to see any output.
+
+stdout/stderr now go into the files C</perl-stdout.txt> and
+C</perl-stderr.txt.>
+
+PerlIDE is handy to deal with perlce.
+
+=head2 LIMITATIONS
+
+No fork(), pipe(), popen() etc.
+
+=head2 ENVIRONMENT
+
+All environment vars must be stored in HKLM\Environment as
+strings. They are read at process startup.
+
+=over
+
+=item PERL5LIB
+
+Usual perl lib path (semi-list).
+
+=item PATH
+
+Semi-list for executables.
+
+=item TMP
+
+- Tempdir.
+
+=item UNIXROOTPATH
+
+- Root for accessing some special files, i.e. C</dev/null>, C</etc/services>.
+
+=item ROWS/COLS
+
+- Rows/cols for console.
+
+=item HOME
+
+- Home directory.
+
+=item CONSOLEFONTSIZE
+
+- Size for console font.
+
+=back
+
+You can set these with cereg.exe, a (remote) registry editor
+or via the PerlIDE.
+
+=head2 REGISTRY
+
+To start perl by clicking on a perl source file, you have
+to make the according entries in HKCR (see C<ce-helpers/wince-reg.bat>).
+cereg.exe (which must be executed on a desktop pc with
+ActiveSync) is reported not to work on some devices.
+You have to create the registry entries by hand using a
+registry editor.
+
+=head2 XS
+
+The following Win32-Methods are built-in:
+
+ newXS("Win32::GetCwd", w32_GetCwd, file);
+ newXS("Win32::SetCwd", w32_SetCwd, file);
+ newXS("Win32::GetTickCount", w32_GetTickCount, file);
+ newXS("Win32::GetOSVersion", w32_GetOSVersion, file);
+ newXS("Win32::IsWinNT", w32_IsWinNT, file);
+ newXS("Win32::IsWin95", w32_IsWin95, file);
+ newXS("Win32::IsWinCE", w32_IsWinCE, file);
+ newXS("Win32::CopyFile", w32_CopyFile, file);
+ newXS("Win32::Sleep", w32_Sleep, file);
+ newXS("Win32::MessageBox", w32_MessageBox, file);
+ newXS("Win32::GetPowerStatus", w32_GetPowerStatus, file);
+ newXS("Win32::GetOemInfo", w32_GetOemInfo, file);
+ newXS("Win32::ShellEx", w32_ShellEx, file);
+
+=head2 BUGS
+
+Opening files for read-write is currently not supported if
+they use stdio (normal perl file handles).
+
+If you find bugs or if it does not work at all on your
+device, send mail to the address below. Please report
+the details of your device (processor, ceversion,
+devicetype (hpc/palm/pocket)) and the date of the downloaded
+files.
+
+=head2 INSTALLATION
+
+Currently installation instructions are at L<http://perlce.sourceforge.net/>.
+
+After installation & testing processes will stabilize, information will
+be more precise.
+
+=head1 ACKNOWLEDGEMENTS
+
+The port for Win32 was used as a reference.
+
+=head1 History of WinCE port
+
+=over
+
+=item 5.6.0
+
+Initial port of perl to WinCE. It was performed in separate directory
+named C<wince>. This port was based on contents of C<./win32> directory.
+C<miniperl> was not built, user must have HOST perl and properly edit
+C<makefile.ce> to reflect this.
+
+=item 5.8.0
+
+wince port was kept in the same C<./wince> directory, and C<wince/Makefile.ce>
+was used to invoke native compiler to create HOST miniperl, which then
+facilitates cross-compiling process.
+Extension building support was added.
+
+=item 5.9.4
+
+Two directories C<./win32> and C<./wince> were merged, so perlce build
+process comes in C<./win32> directory.
+
+=back
+
+=head1 AUTHORS
+
+=over
+
+=item Rainer Keuchel <coyxc@rainer-keuchel.de>
+
+provided initial port of Perl, which appears to be most essential work, as
+it was a breakthrough on having Perl ported at all.
+Many thanks and obligations to Rainer!
+
+=item Vadim Konovalov
+
+made further support of WinCE port.
+
+=back
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcheat.pod b/Master/tlpkg/tlperl/lib/pods/perlcheat.pod
new file mode 100644
index 00000000000..7f2c83066f6
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcheat.pod
@@ -0,0 +1,93 @@
+=head1 NAME
+
+perlcheat - Perl 5 Cheat Sheet
+
+=head1 DESCRIPTION
+
+This 'cheat sheet' is a handy reference, meant for beginning Perl
+programmers. Not everything is mentioned, but 195 features may
+already be overwhelming.
+
+=head2 The sheet
+
+ CONTEXTS SIGILS ARRAYS HASHES
+ void $scalar whole: @array %hash
+ scalar @array slice: @array[0, 2] @hash{'a', 'b'}
+ list %hash element: $array[0] $hash{'a'}
+ &sub
+ *glob SCALAR VALUES
+ number, string, reference, glob, undef
+ REFERENCES
+ \ references $$foo[1] aka $foo->[1]
+ $@%&* dereference $$foo{bar} aka $foo->{bar}
+ [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2]
+ {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2]
+ \() list of refs
+ NUMBERS vs STRINGS LINKS
+ OPERATOR PRECEDENCE = = perl.plover.com
+ -> + . search.cpan.org
+ ++ -- == != eq ne cpan.org
+ ** < > <= >= lt gt le ge pm.org
+ ! ~ \ u+ u- <=> cmp tpj.com
+ =~ !~ perldoc.com
+ * / % x SYNTAX
+ + - . for (LIST) { }, for (a;b;c) { }
+ << >> while ( ) { }, until ( ) { }
+ named uops if ( ) { } elsif ( ) { } else { }
+ < > <= >= lt gt le ge unless ( ) { } elsif ( ) { } else { }
+ == != <=> eq ne cmp ~~ for equals foreach (ALWAYS)
+ &
+ | ^ REGEX METACHARS REGEX MODIFIERS
+ && ^ string begin /i case insens.
+ || // $ str. end (before \n) /m line based ^$
+ .. ... + one or more /s . includes \n
+ ?: * zero or more /x ign. wh.space
+ = += -= *= etc. ? zero or one /g global
+ , => {3,7} repeat in range /o cmpl pat. once
+ list ops () capture
+ not (?:) no capture REGEX CHARCLASSES
+ and [] character class . == [^\n]
+ or xor | alternation \s == whitespace
+ \b word boundary \w == word characters
+ \z string end \d == digits
+ DO \S, \W and \D negate
+ use strict; DON'T
+ use warnings; "$foo" LINKS
+ my $var; $$variable_name perl.com
+ open() or die $!; `$userinput` use.perl.org
+ use Modules; /$userinput/ perl.apache.org
+
+ FUNCTION RETURN LISTS
+ stat localtime caller SPECIAL VARIABLES
+ 0 dev 0 second 0 package $_ default variable
+ 1 ino 1 minute 1 filename $0 program name
+ 2 mode 2 hour 2 line $/ input separator
+ 3 nlink 3 day 3 subroutine $\ output separator
+ 4 uid 4 month-1 4 hasargs $| autoflush
+ 5 gid 5 year-1900 5 wantarray $! sys/libcall error
+ 6 rdev 6 weekday 6 evaltext $@ eval error
+ 7 size 7 yearday 7 is_require $$ process ID
+ 8 atime 8 is_dst 8 hints $. line number
+ 9 mtime 9 bitmask @ARGV command line args
+ 10 ctime just use @INC include paths
+ 11 blksz POSIX:: 3..9 only @_ subroutine args
+ 12 blcks strftime! with EXPR %ENV environment
+
+=head1 ACKNOWLEDGEMENTS
+
+The first version of this document appeared on Perl Monks, where several
+people had useful suggestions. Thank you, Perl Monks.
+
+A special thanks to Damian Conway, who didn't only suggest important changes,
+but also took the time to count the number of listed features and make a
+Perl 6 version to show that Perl will stay Perl.
+
+=head1 AUTHOR
+
+Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks.
+
+=head1 SEE ALSO
+
+ http://perlmonks.org/?node_id=216602 the original PM post
+ http://perlmonks.org/?node_id=238031 Damian Conway's Perl 6 version
+ http://juerd.nl/site.plp/perlcheat home of the Perl Cheat Sheet
diff --git a/Master/tlpkg/tlperl/lib/pods/perlclib.pod b/Master/tlpkg/tlperl/lib/pods/perlclib.pod
new file mode 100644
index 00000000000..1fe4699be1b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlclib.pod
@@ -0,0 +1,212 @@
+=head1 NAME
+
+perlclib - Internal replacements for standard C library functions
+
+=head1 DESCRIPTION
+
+One thing Perl porters should note is that F<perl> doesn't tend to use that
+much of the C standard library internally; you'll see very little use of,
+for example, the F<ctype.h> functions in there. This is because Perl
+tends to reimplement or abstract standard library functions, so that we
+know exactly how they're going to operate.
+
+This is a reference card for people who are familiar with the C library
+and who want to do things the Perl way; to tell them which functions
+they ought to use instead of the more normal C functions.
+
+=head2 Conventions
+
+In the following tables:
+
+=over 3
+
+=item C<t>
+
+is a type.
+
+=item C<p>
+
+is a pointer.
+
+=item C<n>
+
+is a number.
+
+=item C<s>
+
+is a string.
+
+=back
+
+C<sv>, C<av>, C<hv>, etc. represent variables of their respective types.
+
+=head2 File Operations
+
+Instead of the F<stdio.h> functions, you should use the Perl abstraction
+layer. Instead of C<FILE*> types, you need to be handling C<PerlIO*>
+types. Don't forget that with the new PerlIO layered I/O abstraction
+C<FILE*> types may not even be available. See also the C<perlapio>
+documentation for more information about the following functions:
+
+ Instead Of: Use:
+
+ stdin PerlIO_stdin()
+ stdout PerlIO_stdout()
+ stderr PerlIO_stderr()
+
+ fopen(fn, mode) PerlIO_open(fn, mode)
+ freopen(fn, mode, stream) PerlIO_reopen(fn, mode, perlio) (Deprecated)
+ fflush(stream) PerlIO_flush(perlio)
+ fclose(stream) PerlIO_close(perlio)
+
+=head2 File Input and Output
+
+ Instead Of: Use:
+
+ fprintf(stream, fmt, ...) PerlIO_printf(perlio, fmt, ...)
+
+ [f]getc(stream) PerlIO_getc(perlio)
+ [f]putc(stream, n) PerlIO_putc(perlio, n)
+ ungetc(n, stream) PerlIO_ungetc(perlio, n)
+
+Note that the PerlIO equivalents of C<fread> and C<fwrite> are slightly
+different from their C library counterparts:
+
+ fread(p, size, n, stream) PerlIO_read(perlio, buf, numbytes)
+ fwrite(p, size, n, stream) PerlIO_write(perlio, buf, numbytes)
+
+ fputs(s, stream) PerlIO_puts(perlio, s)
+
+There is no equivalent to C<fgets>; one should use C<sv_gets> instead:
+
+ fgets(s, n, stream) sv_gets(sv, perlio, append)
+
+=head2 File Positioning
+
+ Instead Of: Use:
+
+ feof(stream) PerlIO_eof(perlio)
+ fseek(stream, n, whence) PerlIO_seek(perlio, n, whence)
+ rewind(stream) PerlIO_rewind(perlio)
+
+ fgetpos(stream, p) PerlIO_getpos(perlio, sv)
+ fsetpos(stream, p) PerlIO_setpos(perlio, sv)
+
+ ferror(stream) PerlIO_error(perlio)
+ clearerr(stream) PerlIO_clearerr(perlio)
+
+=head2 Memory Management and String Handling
+
+ Instead Of: Use:
+
+ t* p = malloc(n) Newx(id, p, n, t)
+ t* p = calloc(n, s) Newxz(id, p, n, t)
+ p = realloc(p, n) Renew(p, n, t)
+ memcpy(dst, src, n) Copy(src, dst, n, t)
+ memmove(dst, src, n) Move(src, dst, n, t)
+ memcpy(dst, src, sizeof(t)) StructCopy(src, dst, t)
+ memset(dst, 0, n * sizeof(t)) Zero(dst, n, t)
+ memzero(dst, 0) Zero(dst, n, char)
+ free(p) Safefree(p)
+
+ strdup(p) savepv(p)
+ strndup(p, n) savepvn(p, n) (Hey, strndup doesn't exist!)
+
+ strstr(big, little) instr(big, little)
+ strcmp(s1, s2) strLE(s1, s2) / strEQ(s1, s2) / strGT(s1,s2)
+ strncmp(s1, s2, n) strnNE(s1, s2, n) / strnEQ(s1, s2, n)
+
+Notice the different order of arguments to C<Copy> and C<Move> than used
+in C<memcpy> and C<memmove>.
+
+Most of the time, though, you'll want to be dealing with SVs internally
+instead of raw C<char *> strings:
+
+ strlen(s) sv_len(sv)
+ strcpy(dt, src) sv_setpv(sv, s)
+ strncpy(dt, src, n) sv_setpvn(sv, s, n)
+ strcat(dt, src) sv_catpv(sv, s)
+ strncat(dt, src) sv_catpvn(sv, s)
+ sprintf(s, fmt, ...) sv_setpvf(sv, fmt, ...)
+
+Note also the existence of C<sv_catpvf> and C<sv_vcatpvfn>, combining
+concatenation with formatting.
+
+Sometimes instead of zeroing the allocated heap by using Newxz() you
+should consider "poisoning" the data. This means writing a bit
+pattern into it that should be illegal as pointers (and floating point
+numbers), and also hopefully surprising enough as integers, so that
+any code attempting to use the data without forethought will break
+sooner rather than later. Poisoning can be done using the Poison()
+macros, which have similar arguments as Zero():
+
+ PoisonWith(dst, n, t, b) scribble memory with byte b
+ PoisonNew(dst, n, t) equal to PoisonWith(dst, n, t, 0xAB)
+ PoisonFree(dst, n, t) equal to PoisonWith(dst, n, t, 0xEF)
+ Poison(dst, n, t) equal to PoisonFree(dst, n, t)
+
+=head2 Character Class Tests
+
+There are two types of character class tests that Perl implements: one
+type deals in C<char>s and are thus B<not> Unicode aware (and hence
+deprecated unless you B<know> you should use them) and the other type
+deal in C<UV>s and know about Unicode properties. In the following
+table, C<c> is a C<char>, and C<u> is a Unicode codepoint.
+
+ Instead Of: Use: But better use:
+
+ isalnum(c) isALNUM(c) isALNUM_uni(u)
+ isalpha(c) isALPHA(c) isALPHA_uni(u)
+ iscntrl(c) isCNTRL(c) isCNTRL_uni(u)
+ isdigit(c) isDIGIT(c) isDIGIT_uni(u)
+ isgraph(c) isGRAPH(c) isGRAPH_uni(u)
+ islower(c) isLOWER(c) isLOWER_uni(u)
+ isprint(c) isPRINT(c) isPRINT_uni(u)
+ ispunct(c) isPUNCT(c) isPUNCT_uni(u)
+ isspace(c) isSPACE(c) isSPACE_uni(u)
+ isupper(c) isUPPER(c) isUPPER_uni(u)
+ isxdigit(c) isXDIGIT(c) isXDIGIT_uni(u)
+
+ tolower(c) toLOWER(c) toLOWER_uni(u)
+ toupper(c) toUPPER(c) toUPPER_uni(u)
+
+=head2 F<stdlib.h> functions
+
+ Instead Of: Use:
+
+ atof(s) Atof(s)
+ atol(s) Atol(s)
+ strtod(s, &p) Nothing. Just don't use it.
+ strtol(s, &p, n) Strtol(s, &p, n)
+ strtoul(s, &p, n) Strtoul(s, &p, n)
+
+Notice also the C<grok_bin>, C<grok_hex>, and C<grok_oct> functions in
+F<numeric.c> for converting strings representing numbers in the respective
+bases into C<NV>s.
+
+In theory C<Strtol> and C<Strtoul> may not be defined if the machine perl is
+built on doesn't actually have strtol and strtoul. But as those 2
+functions are part of the 1989 ANSI C spec we suspect you'll find them
+everywhere by now.
+
+ int rand() double Drand01()
+ srand(n) { seedDrand01((Rand_seed_t)n);
+ PL_srand_called = TRUE; }
+
+ exit(n) my_exit(n)
+ system(s) Don't. Look at pp_system or use my_popen
+
+ getenv(s) PerlEnv_getenv(s)
+ setenv(s, val) my_putenv(s, val)
+
+=head2 Miscellaneous functions
+
+You should not even B<want> to use F<setjmp.h> functions, but if you
+think you do, use the C<JMPENV> stack in F<scope.h> instead.
+
+For C<signal>/C<sigaction>, use C<rsignal(signo, handler)>.
+
+=head1 SEE ALSO
+
+L<perlapi>, L<perlapio>, L<perlguts>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcn.pod b/Master/tlpkg/tlperl/lib/pods/perlcn.pod
new file mode 100644
index 00000000000..eeb6403d451
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcn.pod
@@ -0,0 +1,150 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+The following documentation is written in EUC-CN encoding.
+
+Èç¹ûÄãÓÃÒ»°ãµÄÎÄ×ֱ༭Æ÷ÔÄÀÀÕâ·ÝÎļþ, ÇëºöÂÔÎÄÖÐÆæÌصÄ×¢¼Ç×Ö·û.
+Õâ·ÝÎļþÊÇÒÔ POD (¼òÃ÷Îļþ¸ñʽ) д³É; ÕâÖÖ¸ñʽÊÇΪÁËÄÜÈÃÈËÖ±½ÓÔĶÁ,
+¶øÌرðÉè¼ÆµÄ. ¹ØÓڴ˸ñʽµÄ½øÒ»²½ÐÅÏ¢, Çë²Î¿¼ perlpod ÏßÉÏÎļþ.
+
+=encoding euc-cn
+
+=head1 NAME
+
+perlcn - ¼òÌåÖÐÎÄ Perl Ö¸ÄÏ
+
+=head1 DESCRIPTION
+
+»¶Ó­À´µ½ Perl µÄÌìµØ!
+
+´Ó 5.8.0 °æ¿ªÊ¼, Perl ¾ß±¸ÁËÍêÉÆµÄ Unicode (ͳһÂë) Ö§Ô®,
+Ò²Á¬´øÖ§Ô®ÁËÐí¶àÀ­¶¡ÓïϵÒÔÍâµÄ±àÂ뷽ʽ; CJK (ÖÐÈÕº«) ±ãÊÇÆäÖеÄÒ»²¿·Ý.
+Unicode Êǹú¼ÊÐԵıê×¼, ÊÔͼº­¸ÇÊÀ½çÉÏËùÓеÄ×Ö·û: Î÷·½ÊÀ½ç, ¶«·½ÊÀ½ç,
+ÒÔ¼°Á½Õß¼äµÄÒ»ÇÐ (Ï£À°ÎÄ, ÐðÀûÑÇÎÄ, ÑÇÀ­²®ÎÄ, Ï£²®À´ÎÄ, Ó¡¶ÈÎÄ,
+Ó¡µØ°²ÎÄ, µÈµÈ). ËüÒ²ÈÝÄÉÁ˶àÖÖ×÷ҵϵͳÓëƽ̨ (Èç PC ¼°Âó½ðËþ).
+
+Perl ±¾ÉíÒÔ Unicode ½øÐвÙ×÷. Õâ±íʾ Perl ÄÚ²¿µÄ×Ö·û´®Êý¾Ý¿ÉÓà Unicode
+±íʾ; Perl µÄº¯Ê½ÓëËã·û (ÀýÈçÕý¹æ±íʾʽ±È¶Ô) Ò²ÄÜ¶Ô Unicode ½øÐвÙ×÷.
+ÔÚÊäÈë¼°Êä³öʱ, ΪÁË´¦ÀíÒÔ Unicode ֮ǰµÄ±àÂ뷽ʽ´æ·ÅµÄÊý¾Ý, Perl
+ÌṩÁË Encode Õâ¸öÄ£¿é, ¿ÉÒÔÈÃÄãÇáÒ׵ضÁÈ¡¼°Ð´Èë¾ÉÓеıàÂëÊý¾Ý.
+
+Encode ÑÓÉìÄ£¿éÖ§Ô®ÏÂÁмòÌåÖÐÎĵıàÂ뷽ʽ ('gb2312' ±íʾ 'euc-cn'):
+
+ euc-cn Unix ÑÓÉì×Ö·û¼¯, Ò²¾ÍÊÇË׳ƵĹú±êÂë
+ gb2312-raw δ¾­´¦ÀíµÄ (µÍ±ÈÌØ) GB2312 ×Ö·û±í
+ gb12345 δ¾­´¦ÀíµÄÖйúÓ÷±ÌåÖÐÎıàÂë
+ iso-ir-165 GB2312 + GB6345 + GB8565 + ÐÂÔö×Ö·û
+ cp936 ×ÖÂëÒ³ 936, Ò²¿ÉÒÔÓà 'GBK' (À©³ä¹ú±êÂë) Ö¸Ã÷
+ hz 7 ±ÈÌØÒݳöʽ GB2312 ±àÂë
+
+¾ÙÀýÀ´Ëµ, ½« EUC-CN ±àÂëµÄµµ°¸×ª³É Unicode, ìóÐè¼üÈëÏÂÁÐÖ¸Áî:
+
+ perl -Mencoding=euc-cn,STDOUT,utf8 -pe1 < file.euc-cn > file.utf8
+
+Perl Ò²ÄÚ¸½ÁË "piconv", Ò»Ö§ÍêÈ«ÒÔ Perl д³ÉµÄ×Ö·ûת»»¹¤¾ß³ÌÐò, Ó÷¨ÈçÏÂ:
+
+ piconv -f euc-cn -t utf8 < file.euc-cn > file.utf8
+ piconv -f utf8 -t euc-cn < file.utf8 > file.euc-cn
+
+ÁíÍâ, ÀûÓà encoding Ä£¿é, Äã¿ÉÒÔÇáÒ×д³öÒÔ×Ö·ûΪµ¥Î»µÄ³ÌÐòÂë, ÈçÏÂËùʾ:
+
+ #!/usr/bin/env perl
+ # Æô¶¯ euc-cn ×Ö´®½âÎö; ±ê×¼Êä³öÈë¼°±ê×¼´íÎó¶¼ÉèΪ euc-cn ±àÂë
+ use encoding 'euc-cn', STDIN => 'euc-cn', STDOUT => 'euc-cn';
+ print length("ÂæÍÕ"); # 2 (Ë«ÒýºÅ±íʾ×Ö·û)
+ print length('ÂæÍÕ'); # 4 (µ¥ÒýºÅ±íʾ×Ö½Ú)
+ print index("×»×»½Ì»å", "»×»½"); # -1 (²»°üº¬´Ë×Ó×Ö·û´®)
+ print index('×»×»½Ì»å', '»×»½'); # 1 (´ÓµÚ¶þ¸ö×Ö½Ú¿ªÊ¼)
+
+ÔÚ×îºóÒ»ÁÐÀý×ÓÀï, "×»" µÄµÚ¶þ¸ö×Ö½ÚÓë "×»" µÄµÚÒ»¸ö×Ö½Ú½áºÏ³É EUC-CN
+ÂëµÄ "»×"; "×»" µÄµÚ¶þ¸ö×Ö½ÚÔòÓë "½Ì" µÄµÚÒ»¸ö×Ö½Ú½áºÏ³É "»½".
+Õâ½â¾öÁËÒÔÇ° EUC-CN Âë±È¶Ô´¦ÀíÉϳ£¼ûµÄÎÊÌâ.
+
+=head2 ¶îÍâµÄÖÐÎıàÂë
+
+Èç¹ûÐèÒª¸ü¶àµÄÖÐÎıàÂë, ¿ÉÒÔ´Ó CPAN (L<http://www.cpan.org/>) ÏÂÔØ
+Encode::HanExtra Ä£¿é. ËüÄ¿Ç°ÌṩÏÂÁбàÂ뷽ʽ:
+
+ gb18030 À©³ä¹ýµÄ¹ú±êÂë, °üº¬·±ÌåÖÐÎÄ
+
+ÁíÍâ, Encode::HanConvert Ä£¿éÔòÌṩÁ˼ò·±×ª»»ÓõÄÁ½ÖÖ±àÂë:
+
+ big5-simp Big5 ·±ÌåÖÐÎÄÓë Unicode ¼òÌåÖÐÎÄ»¥×ª
+ gbk-trad GBK ¼òÌåÖÐÎÄÓë Unicode ·±ÌåÖÐÎÄ»¥×ª
+
+ÈôÏëÔÚ GBK Óë Big5 Ö®¼ä»¥×ª, Çë²Î¿¼¸ÃÄ£¿éÄÚ¸½µÄ b2g.pl Óë g2b.pl Á½Ö§³ÌÐò,
+»òÔÚ³ÌÐòÄÚʹÓÃÏÂÁÐд·¨:
+
+ use Encode::HanConvert;
+ $euc_cn = big5_to_gb($big5); # ´Ó Big5 תΪ GBK
+ $big5 = gb_to_big5($euc_cn); # ´Ó GBK תΪ Big5
+
+=head2 ½øÒ»²½µÄÐÅÏ¢
+
+Çë²Î¿¼ Perl ÄÚ¸½µÄ´óÁ¿ËµÃ÷Îļþ (²»ÐÒÈ«ÊÇÓÃÓ¢ÎÄдµÄ), À´Ñ§Ï°¸ü¶à¹ØÓÚ
+Perl µÄ֪ʶ, ÒÔ¼° Unicode µÄʹÓ÷½Ê½. ²»¹ý, ÍⲿµÄ×ÊÔ´Ï൱·á¸»:
+
+=head2 Ìṩ Perl ×ÊÔ´µÄÍøÖ·
+
+=over 4
+
+=item L<http://www.perl.com/>
+
+Perl µÄÊ×Ò³ (ÓÉÅ·À³Àñ¹«Ë¾Î¬»¤)
+
+=item L<http://www.cpan.org/>
+
+Perl ×ۺϵä²ØÍø (Comprehensive Perl Archive Network)
+
+=item L<http://lists.perl.org/>
+
+Perl ÓʵÝÂÛ̳һÀÀ
+
+=back
+
+=head2 ѧϰ Perl µÄÍøÖ·
+
+=over 4
+
+=item L<http://www.oreilly.com.cn/indexcat.php?c=perl>
+
+¼òÌåÖÐÎÄ°æµÄÅ·À³Àñ Perl Êé½å
+
+=back
+
+=head2 Perl ʹÓÃÕß¼¯»á
+
+=over 4
+
+=item L<http://www.pm.org/groups/asia.html>
+
+Öйú Perl Íƹã×éÒ»ÀÀ
+
+=back
+
+=head2 Unicode Ïà¹ØÍøÖ·
+
+=over 4
+
+=item L<http://www.unicode.org/>
+
+Unicode ѧÊõѧ»á (Unicode ±ê×¼µÄÖƶ¨Õß)
+
+=item L<http://www.cl.cam.ac.uk/%7Emgk25/unicode.html>
+
+Unix/Linux É쵀 UTF-8 ¼° Unicode ´ð¿ÍÎÊ
+
+=back
+
+=head1 SEE ALSO
+
+L<Encode>, L<Encode::CN>, L<encoding>, L<perluniintro>, L<perlunicode>
+
+=head1 AUTHORS
+
+Jarkko Hietaniemi E<lt>jhi@iki.fiE<gt>
+
+Audrey Tang (ÌÆ·ï) E<lt>audreyt@audreyt.orgE<gt>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcommunity.pod b/Master/tlpkg/tlperl/lib/pods/perlcommunity.pod
new file mode 100644
index 00000000000..8430c3fcc10
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcommunity.pod
@@ -0,0 +1,158 @@
+=head1 NAME
+
+perlcommunity - a brief overview of the Perl community
+
+=head1 DESCRIPTION
+
+This document aims to provide an overview of the vast perl community, which is
+far too large and diverse to provide a detailed listing. If any specific niche
+has been forgotten, it is not meant as an insult but an omission for the sake
+of brevity.
+
+The Perl community is as diverse as Perl, and there is a large amount of
+evidence that the Perl users apply TMTOWTDI to all endeavors, not just
+programming. From websites, to IRC, to mailing lists, there is more than one
+way to get involved in the community.
+
+=head2 Where to find the community
+
+There is a central directory for the Perl community: L<http://perl.org>
+maintained by the Perl Foundation (L<http://www.perlfoundation.org/>),
+which tracks and provides services for a variety of other community sites.
+
+=head2 Mailing lists and Newsgroups
+
+Perl runs on e-mail, there is no doubt about it. The Camel book was originally
+written mostly over e-mail and today Perl's development is co-ordinated through
+mailing lists. The largest repository of Perl mailing lists is located at
+L<http://lists.perl.org>.
+
+Most Perl-related projects set up mailing lists for both users and
+contributors. If you don't see a certain project listed at
+L<http://lists.perl.org>, check the particular website for that project.
+Most mailing lists are archived at L<http://nntp.perl.org/>.
+
+There are also plenty of Perl related newsgroups located under
+C<comp.lang.perl.*>.
+
+=head2 IRC
+
+The Perl community has a rather large IRC presence. For starters, it has its
+own IRC network, L<irc://irc.perl.org>. General (not help-oriented) chat can be
+found at L<irc://irc.perl.org/#perl>. Many other more specific chats are also
+hosted on the network. Information about irc.perl.org is located on the
+network's website: L<http://www.irc.perl.org>. For a more help oriented #perl,
+check out L<irc://irc.freenode.net/#perl>. Perl 6 development also has a
+presence in L<irc://irc.freenode.net/#perl6>. Most Perl-related channels will
+be kind enough to point you in the right direction if you ask nicely.
+
+Any large IRC network (Dalnet, EFnet) is also likely to have a #perl channel,
+with varying activity levels.
+
+=head2 Websites
+
+Perl websites come in a variety of forms, but they fit into two large
+categories: forums and news websites. There are many Perl related
+websites, so only a few of the community's largest are mentioned here.
+
+=head3 News sites
+
+=over 4
+
+=item L<http://perl.com/>
+
+Run by O'Reilly Media (The publisher of L<the Camel Book|perlbook> among other
+Perl-related literature), perl.com provides current Perl news, articles, and
+resources for Perl developers as well as a directory of other useful websites.
+
+=item L<http://use.perl.org/>
+
+use Perl; provides a slashdot-style Perl news website covering all things Perl,
+from minutes of the meetings of the Perl 6 Design team to conference
+announcements with (ir)relevant discussion.
+
+=back
+
+=head3 Forums
+
+=over 4
+
+=item L<http://www.perlmonks.org/>
+
+PerlMonks is one of the largest Perl forums, and describes itself as "A place
+for individuals to polish, improve, and showcase their Perl skills." and "A
+community which allows everyone to grow and learn from each other."
+
+=back
+
+=head2 User Groups
+
+Many cities around the world have local Perl Mongers chapters. A Perl Mongers
+chapter is a local user group which typically holds regular in-person meetings,
+both social and technical; helps organize local conferences, workshops, and
+hackathons; and provides a mailing list or other continual contact method for
+its members to keep in touch.
+
+To find your local Perl Mongers (or PM as they're commonly abbreviated) group
+check the international Perl Mongers directory at L<http://www.pm.org/>.
+
+=head2 Workshops
+
+Perl workshops are, as the name might suggest, workshops where Perl is taught
+in a variety of ways. At the workshops, subjects range from a beginner's
+introduction (such as the Pittsburgh Perl Workshop's "Zero To Perl") to much
+more advanced subjects.
+
+There are several great resources for locating workshops: the
+L<websites|"Websites"> mentioned above, the
+L<calendar|"Calendar of Perl Events"> mentioned below, and the YAPC Europe
+website, L<http://www.yapceurope.org/>, which is probably the best resource for
+European Perl events.
+
+=head2 Hackathons
+
+Hackathons are a very different kind of gathering where Perl hackers gather to
+do just that, hack nonstop for an extended (several day) period on a specific
+project or projects. Information about hackathons can be located in the same
+place as information about L<workshops|"Workshops"> as well as in
+L<irc://irc.perl.org/#perl>.
+
+If you have never been to a hackathon, here are a few basic things you need to
+know before attending: have a working laptop and know how to use it; check out
+the involved projects before hand; have the necessary version control client;
+and bring backup equipment (an extra LAN cable, additional power strips, etc.)
+because someone will forget.
+
+=head2 Conventions
+
+Perl has two major annual conventions: The Perl Conference (now part of OSCON),
+put on by O'Reilly, and Yet Another Perl Conference or YAPC (pronounced
+yap-see), which is localized into several regional YAPCs (North America,
+Europe, Asia) in a stunning grassroots display by the Perl community. For more
+information about either conference, check out their respective web pages:
+OSCON L<http://conferences.oreillynet.com/>; YAPC L<http://www.yapc.org>.
+
+A relatively new conference franchise with a large Perl portion is the
+Open Source Developers Conference or OSDC. First held in Australia it has
+recently also spread to Israel and France. More information can be found at:
+L<http://www.osdc.com.au/> for Australia, L<http://www.osdc.org.il>
+for Israel, and L<http://www.osdc.fr/> for France.
+
+=head2 Calendar of Perl Events
+
+The Perl Review, L<http://www.theperlreview.com> maintains a website
+and Google calendar
+(L<http://www.theperlreview.com/community_calendar>) for tracking
+workshops, hackathons, Perl Mongers meetings, and other events. Views
+of this calendar are at L<http://www.perl.org/events.html> and
+L<http://www.yapc.org>.
+
+Not every event or Perl Mongers group is on that calendar, so don't lose
+heart if you don't see yours posted. To have your event or group listed,
+contact brian d foy (brian@theperlreview.com).
+
+=head1 AUTHOR
+
+Edgar "Trizor" Bering <trizor@gmail.com>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcompile.pod b/Master/tlpkg/tlperl/lib/pods/perlcompile.pod
new file mode 100644
index 00000000000..505ce68384f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcompile.pod
@@ -0,0 +1,293 @@
+=head1 NAME
+
+perlcompile - Introduction to the Perl Compiler-Translator
+
+=head1 DESCRIPTION
+
+Perl has always had a compiler: your source is compiled into an
+internal form (a parse tree) which is then optimized before being
+run. Since version 5.005, Perl has shipped with a module
+capable of inspecting the optimized parse tree (C<B>), and this has
+been used to write many useful utilities, including a module that lets
+you turn your Perl into C source code that can be compiled into a
+native executable.
+
+The C<B> module provides access to the parse tree, and other modules
+("back ends") do things with the tree. Some write it out as
+semi-human-readable text. Another traverses the parse tree to build a
+cross-reference of which subroutines, formats, and variables are used
+where. Another checks your code for dubious constructs. Yet another back
+end dumps the parse tree back out as Perl source, acting as a source code
+beautifier or deobfuscator.
+
+Because its original purpose was to be a way to produce C code
+corresponding to a Perl program, and in turn a native executable, the
+C<B> module and its associated back ends are known as "the
+compiler", even though they don't really compile anything.
+Different parts of the compiler are more accurately a "translator",
+or an "inspector", but people want Perl to have a "compiler
+option" not an "inspector gadget". What can you do?
+
+This document covers the use of the Perl compiler: which modules
+it comprises, how to use the most important of the back end modules,
+what problems there are, and how to work around them.
+
+=head2 Layout
+
+The compiler back ends are in the C<B::> hierarchy, and the front-end
+(the module that you, the user of the compiler, will sometimes
+interact with) is the O module.
+
+Here are the important back ends to know about, with their status
+expressed as a number from 0 (outline for later implementation) to
+10 (if there's a bug in it, we're very surprised):
+
+=over 4
+
+=item B::Lint
+
+Complains if it finds dubious constructs in your source code. Status:
+6 (it works adequately, but only has a very limited number of areas
+that it checks).
+
+=item B::Deparse
+
+Recreates the Perl source, making an attempt to format it coherently.
+Status: 8 (it works nicely, but a few obscure things are missing).
+
+=item B::Xref
+
+Reports on the declaration and use of subroutines and variables.
+Status: 8 (it works nicely, but still has a few lingering bugs).
+
+=back
+
+=head1 Using The Back Ends
+
+The following sections describe how to use the various compiler back
+ends. They're presented roughly in order of maturity, so that the
+most stable and proven back ends are described first, and the most
+experimental and incomplete back ends are described last.
+
+The O module automatically enabled the B<-c> flag to Perl, which
+prevents Perl from executing your code once it has been compiled.
+This is why all the back ends print:
+
+ myperlprogram syntax OK
+
+before producing any other output.
+
+=head2 The Cross Referencing Back End
+
+The cross referencing back end (B::Xref) produces a report on your program,
+breaking down declarations and uses of subroutines and variables (and
+formats) by file and subroutine. For instance, here's part of the
+report from the I<pod2man> program that comes with Perl:
+
+ Subroutine clear_noremap
+ Package (lexical)
+ $ready_to_print i1069, 1079
+ Package main
+ $& 1086
+ $. 1086
+ $0 1086
+ $1 1087
+ $2 1085, 1085
+ $3 1085, 1085
+ $ARGV 1086
+ %HTML_Escapes 1085, 1085
+
+This shows the variables used in the subroutine C<clear_noremap>. The
+variable C<$ready_to_print> is a my() (lexical) variable,
+B<i>ntroduced (first declared with my()) on line 1069, and used on
+line 1079. The variable C<$&> from the main package is used on 1086,
+and so on.
+
+A line number may be prefixed by a single letter:
+
+=over 4
+
+=item i
+
+Lexical variable introduced (declared with my()) for the first time.
+
+=item &
+
+Subroutine or method call.
+
+=item s
+
+Subroutine defined.
+
+=item r
+
+Format defined.
+
+=back
+
+The most useful option the cross referencer has is to save the report
+to a separate file. For instance, to save the report on
+I<myperlprogram> to the file I<report>:
+
+ $ perl -MO=Xref,-oreport myperlprogram
+
+=head2 The Decompiling Back End
+
+The Deparse back end turns your Perl source back into Perl source. It
+can reformat along the way, making it useful as a deobfuscator. The
+most basic way to use it is:
+
+ $ perl -MO=Deparse myperlprogram
+
+You'll notice immediately that Perl has no idea of how to paragraph
+your code. You'll have to separate chunks of code from each other
+with newlines by hand. However, watch what it will do with
+one-liners:
+
+ $ perl -MO=Deparse -e '$op=shift||die "usage: $0
+ code [...]";chomp(@ARGV=<>)unless@ARGV; for(@ARGV){$was=$_;eval$op;
+ die$@ if$@; rename$was,$_ unless$was eq $_}'
+ -e syntax OK
+ $op = shift @ARGV || die("usage: $0 code [...]");
+ chomp(@ARGV = <ARGV>) unless @ARGV;
+ foreach $_ (@ARGV) {
+ $was = $_;
+ eval $op;
+ die $@ if $@;
+ rename $was, $_ unless $was eq $_;
+ }
+
+The decompiler has several options for the code it generates. For
+instance, you can set the size of each indent from 4 (as above) to
+2 with:
+
+ $ perl -MO=Deparse,-si2 myperlprogram
+
+The B<-p> option adds parentheses where normally they are omitted:
+
+ $ perl -MO=Deparse -e 'print "Hello, world\n"'
+ -e syntax OK
+ print "Hello, world\n";
+ $ perl -MO=Deparse,-p -e 'print "Hello, world\n"'
+ -e syntax OK
+ print("Hello, world\n");
+
+See L<B::Deparse> for more information on the formatting options.
+
+=head2 The Lint Back End
+
+The lint back end (B::Lint) inspects programs for poor style. One
+programmer's bad style is another programmer's useful tool, so options
+let you select what is complained about.
+
+To run the style checker across your source code:
+
+ $ perl -MO=Lint myperlprogram
+
+To disable context checks and undefined subroutines:
+
+ $ perl -MO=Lint,-context,-undefined-subs myperlprogram
+
+See L<B::Lint> for information on the options.
+
+=head1 Module List for the Compiler Suite
+
+=over 4
+
+=item B
+
+This module is the introspective ("reflective" in Java terms)
+module, which allows a Perl program to inspect its innards. The
+back end modules all use this module to gain access to the compiled
+parse tree. You, the user of a back end module, will not need to
+interact with B.
+
+=item O
+
+This module is the front-end to the compiler's back ends. Normally
+called something like this:
+
+ $ perl -MO=Deparse myperlprogram
+
+This is like saying C<use O 'Deparse'> in your Perl program.
+
+=item B::Concise
+
+This module prints a concise (but complete) version of the Perl parse
+tree. Its output is more customizable than the one of B::Terse or
+B::Debug (and it can emulate them). This module useful for people who
+are writing their own back end, or who are learning about the Perl
+internals. It's not useful to the average programmer.
+
+=item B::Debug
+
+This module dumps the Perl parse tree in verbose detail to STDOUT.
+It's useful for people who are writing their own back end, or who
+are learning about the Perl internals. It's not useful to the
+average programmer.
+
+=item B::Deparse
+
+This module produces Perl source code from the compiled parse tree.
+It is useful in debugging and deconstructing other people's code,
+also as a pretty-printer for your own source. See
+L</"The Decompiling Back End"> for details about usage.
+
+=item B::Lint
+
+This module inspects the compiled form of your source code for things
+which, while some people frown on them, aren't necessarily bad enough
+to justify a warning. For instance, use of an array in scalar context
+without explicitly saying C<scalar(@array)> is something that Lint
+can identify. See L</"The Lint Back End"> for details about usage.
+
+=item B::Showlex
+
+This module prints out the my() variables used in a function or a
+file. To get a list of the my() variables used in the subroutine
+mysub() defined in the file myperlprogram:
+
+ $ perl -MO=Showlex,mysub myperlprogram
+
+To get a list of the my() variables used in the file myperlprogram:
+
+ $ perl -MO=Showlex myperlprogram
+
+[BROKEN]
+
+=item B::Terse
+
+This module prints the contents of the parse tree, but without as much
+information as B::Debug. For comparison, C<print "Hello, world.">
+produced 96 lines of output from B::Debug, but only 6 from B::Terse.
+
+This module is useful for people who are writing their own back end,
+or who are learning about the Perl internals. It's not useful to the
+average programmer.
+
+=item B::Xref
+
+This module prints a report on where the variables, subroutines, and
+formats are defined and used within a program and the modules it
+loads. See L</"The Cross Referencing Back End"> for details about
+usage.
+
+=back
+
+=head1 KNOWN PROBLEMS
+
+BEGIN{} blocks are executed while compiling your code. Any external
+state that is initialized in BEGIN{}, such as opening files, initiating
+database connections etc., do not behave properly. To work around
+this, Perl has an INIT{} block that corresponds to code being executed
+before your program begins running but after your program has finished
+being compiled. Execution order: BEGIN{}, (possible save of state
+through compiler back-end), INIT{}, program runs, END{}.
+
+=head1 AUTHOR
+
+This document was originally written by Nathan Torkington, and is now
+maintained by the perl5-porters mailing list
+I<perl5-porters@perl.org>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlcygwin.pod b/Master/tlpkg/tlperl/lib/pods/perlcygwin.pod
new file mode 100644
index 00000000000..3933e562a47
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlcygwin.pod
@@ -0,0 +1,784 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+README.cygwin - Perl for Cygwin
+
+=head1 SYNOPSIS
+
+This document will help you configure, make, test and install Perl
+on Cygwin. This document also describes features of Cygwin that will
+affect how Perl behaves at runtime.
+
+B<NOTE:> There are pre-built Perl packages available for Cygwin and a
+version of Perl is provided in the normal Cygwin install. If you do
+not need to customize the configuration, consider using one of those
+packages.
+
+
+=head1 PREREQUISITES FOR COMPILING PERL ON CYGWIN
+
+=head2 Cygwin = GNU+Cygnus+Windows (Don't leave UNIX without it)
+
+The Cygwin tools are ports of the popular GNU development tools for Win32
+platforms. They run thanks to the Cygwin library which provides the UNIX
+system calls and environment these programs expect. More information
+about this project can be found at:
+
+ F<http://www.cygwin.com/>
+
+A recent net or commercial release of Cygwin is required.
+
+At the time this document was last updated, Cygwin 1.5.24 was current.
+
+
+=head2 Cygwin Configuration
+
+While building Perl some changes may be necessary to your Cygwin setup so
+that Perl builds cleanly. These changes are B<not> required for normal
+Perl usage.
+
+B<NOTE:> The binaries that are built will run on all Win32 versions.
+They do not depend on your host system (Win9x/WinME, WinNT/Win2K)
+or your Cygwin configuration (I<ntea>, I<ntsec>, binary/text mounts).
+The only dependencies come from hard-coded pathnames like C</usr/local>.
+However, your host system and Cygwin configuration will affect Perl's
+runtime behavior (see L</"TEST">).
+
+=over 4
+
+=item * C<PATH>
+
+Set the C<PATH> environment variable so that Configure finds the Cygwin
+versions of programs. Any Windows directories should be removed or
+moved to the end of your C<PATH>.
+
+=item * I<nroff>
+
+If you do not have I<nroff> (which is part of the I<groff> package),
+Configure will B<not> prompt you to install I<man> pages.
+
+=item * Permissions
+
+On WinNT with either the I<ntea> or I<ntsec> C<CYGWIN> settings, directory
+and file permissions may not be set correctly. Since the build process
+creates directories and files, to be safe you may want to run a
+C<chmod -R +w *> on the entire Perl source tree.
+
+Also, it is a well known WinNT "feature" that files created by a login
+that is a member of the I<Administrators> group will be owned by the
+I<Administrators> group. Depending on your umask, you may find that you
+can not write to files that you just created (because you are no longer
+the owner). When using the I<ntsec> C<CYGWIN> setting, this is not an
+issue because it "corrects" the ownership to what you would expect on
+a UNIX system.
+
+=back
+
+=head1 CONFIGURE PERL ON CYGWIN
+
+The default options gathered by Configure with the assistance of
+F<hints/cygwin.sh> will build a Perl that supports dynamic loading
+(which requires a shared F<libperl.dll>).
+
+This will run Configure and keep a record:
+
+ ./Configure 2>&1 | tee log.configure
+
+If you are willing to accept all the defaults run Configure with B<-de>.
+However, several useful customizations are available.
+
+=head2 Stripping Perl Binaries on Cygwin
+
+It is possible to strip the EXEs and DLLs created by the build process.
+The resulting binaries will be significantly smaller. If you want the
+binaries to be stripped, you can either add a B<-s> option when Configure
+prompts you,
+
+ Any additional ld flags (NOT including libraries)? [none] -s
+ Any special flags to pass to g++ to create a dynamically loaded library?
+ [none] -s
+ Any special flags to pass to gcc to use dynamic linking? [none] -s
+
+or you can edit F<hints/cygwin.sh> and uncomment the relevant variables
+near the end of the file.
+
+=head2 Optional Libraries for Perl on Cygwin
+
+Several Perl functions and modules depend on the existence of
+some optional libraries. Configure will find them if they are
+installed in one of the directories listed as being used for library
+searches. Pre-built packages for most of these are available from
+the Cygwin installer.
+
+=over 4
+
+=item * C<-lcrypt>
+
+The crypt package distributed with Cygwin is a Linux compatible 56-bit
+DES crypt port by Corinna Vinschen.
+
+Alternatively, the crypt libraries in GNU libc have been ported to Cygwin.
+
+The DES based Ultra Fast Crypt port was done by Alexey Truhan:
+
+ ftp://ftp.franken.de/pub/win32/develop/gnuwin32/cygwin/porters/Okhapkin_Sergey/cw32crypt-dist-0.tgz
+
+NOTE: There are various export restrictions on DES implementations,
+see the glibc README for more details.
+
+The MD5 port was done by Andy Piper:
+
+ ftp://ftp.franken.de/pub/win32/develop/gnuwin32/cygwin/porters/Okhapkin_Sergey/libcrypt.tgz
+
+=item * C<-lgdbm_compat> (C<use GDBM_File>)
+
+GDBM is available for Cygwin.
+
+NOTE: The GDBM library only works on NTFS partitions.
+
+=item * C<-ldb> (C<use DB_File>)
+
+BerkeleyDB is available for Cygwin.
+
+NOTE: The BerkeleyDB library only completely works on NTFS partitions
+and db-4.3 is flawed.
+
+=item * C<cygserver> (C<use IPC::SysV>)
+
+A port of SysV IPC is available for Cygwin.
+
+NOTE: This has B<not> been extensively tested. In particular,
+C<d_semctl_semun> is undefined because it fails a Configure test
+and on Win9x the I<shm*()> functions seem to hang. It also creates
+a compile time dependency because F<perl.h> includes F<<sys/ipc.h>>
+and F<<sys/sem.h>> (which will be required in the future when compiling
+CPAN modules). CURRENTLY NOT SUPPORTED!
+
+=item * C<-lutil>
+
+Included with the standard Cygwin netrelease is the inetutils package
+which includes libutil.a.
+
+=back
+
+=head2 Configure-time Options for Perl on Cygwin
+
+The F<INSTALL> document describes several Configure-time options. Some of
+these will work with Cygwin, others are not yet possible. Also, some of
+these are experimental. You can either select an option when Configure
+prompts you or you can define (undefine) symbols on the command line.
+
+=over 4
+
+=item * C<-Uusedl>
+
+Undefining this symbol forces Perl to be compiled statically.
+
+=item * C<-Uusemymalloc>
+
+By default Perl uses the C<malloc()> included with the Perl source. If you
+want to force Perl to build with the system C<malloc()> undefine this symbol.
+
+=item * C<-Uuseperlio>
+
+Undefining this symbol disables the PerlIO abstraction. PerlIO is now the
+default; it is not recommended to disable PerlIO.
+
+=item * C<-Dusemultiplicity>
+
+Multiplicity is required when embedding Perl in a C program and using
+more than one interpreter instance. This works with the Cygwin port.
+
+=item * C<-Duse64bitint>
+
+By default Perl uses 32 bit integers. If you want to use larger 64
+bit integers, define this symbol.
+
+=item * C<-Duselongdouble>
+
+I<gcc> supports long doubles (12 bytes). However, several additional
+long double math functions are necessary to use them within Perl
+(I<{atan2, cos, exp, floor, fmod, frexp, isnan, log, modf, pow, sin, sqrt}l,
+strtold>).
+These are B<not> yet available with Cygwin.
+
+=item * C<-Dusethreads>
+
+POSIX threads are implemented in Cygwin, define this symbol if you want
+a threaded perl.
+
+=item * C<-Duselargefiles>
+
+Cygwin uses 64-bit integers for internal size and position calculations,
+this will be correctly detected and defined by Configure.
+
+=item * C<-Dmksymlinks>
+
+Use this to build perl outside of the source tree. This works with Cygwin.
+Details can be found in the F<INSTALL> document. This is the recommended
+way to build perl from sources.
+
+=back
+
+=head2 Suspicious Warnings on Cygwin
+
+You may see some messages during Configure that seem suspicious.
+
+=over 4
+
+=item * Win9x and C<d_eofnblk>
+
+Win9x does not correctly report C<EOF> with a non-blocking read on a
+closed pipe. You will see the following messages:
+
+ But it also returns -1 to signal EOF, so be careful!
+ WARNING: you can't distinguish between EOF and no data!
+
+ *** WHOA THERE!!! ***
+ The recommended value for $d_eofnblk on this machine was "define"!
+ Keep the recommended value? [y]
+
+At least for consistency with WinNT, you should keep the recommended
+value.
+
+=item * Compiler/Preprocessor defines
+
+The following error occurs because of the Cygwin C<#define> of
+C<_LONG_DOUBLE>:
+
+ Guessing which symbols your C compiler and preprocessor define...
+ try.c:<line#>: missing binary operator
+
+This failure does not seem to cause any problems. With older gcc
+versions, "parse error" is reported instead of "missing binary
+operator".
+
+=back
+
+=head1 MAKE ON CYGWIN
+
+Simply run I<make> and wait:
+
+ make 2>&1 | tee log.make
+
+=head1 TEST ON CYGWIN
+
+There are two steps to running the test suite:
+
+ make test 2>&1 | tee log.make-test
+
+ cd t; ./perl harness 2>&1 | tee ../log.harness
+
+The same tests are run both times, but more information is provided when
+running as C<./perl harness>.
+
+Test results vary depending on your host system and your Cygwin
+configuration. If a test can pass in some Cygwin setup, it is always
+attempted and explainable test failures are documented. It is possible
+for Perl to pass all the tests, but it is more likely that some tests
+will fail for one of the reasons listed below.
+
+=head2 File Permissions on Cygwin
+
+UNIX file permissions are based on sets of mode bits for
+{read,write,execute} for each {user,group,other}. By default Cygwin
+only tracks the Win32 read-only attribute represented as the UNIX file
+user write bit (files are always readable, files are executable if they
+have a F<.{com,bat,exe}> extension or begin with C<#!>, directories are
+always readable and executable). On WinNT with the I<ntea> C<CYGWIN>
+setting, the additional mode bits are stored as extended file attributes.
+On WinNT with the default I<ntsec> C<CYGWIN> setting, permissions use the
+standard WinNT security descriptors and access control lists. Without one of
+these options, these tests will fail (listing not updated yet):
+
+ Failed Test List of failed
+ ------------------------------------
+ io/fs.t 5, 7, 9-10
+ lib/anydbm.t 2
+ lib/db-btree.t 20
+ lib/db-hash.t 16
+ lib/db-recno.t 18
+ lib/gdbm.t 2
+ lib/ndbm.t 2
+ lib/odbm.t 2
+ lib/sdbm.t 2
+ op/stat.t 9, 20 (.tmp not an executable extension)
+
+=head2 NDBM_File and ODBM_File do not work on FAT filesystems
+
+Do not use NDBM_File or ODBM_File on FAT filesystem. They can be
+built on a FAT filesystem, but many tests will fail:
+
+ ../ext/NDBM_File/ndbm.t 13 3328 71 59 83.10% 1-2 4 16-71
+ ../ext/ODBM_File/odbm.t 255 65280 ?? ?? % ??
+ ../lib/AnyDBM_File.t 2 512 12 2 16.67% 1 4
+ ../lib/Memoize/t/errors.t 0 139 11 5 45.45% 7-11
+ ../lib/Memoize/t/tie_ndbm.t 13 3328 4 4 100.00% 1-4
+ run/fresh_perl.t 97 1 1.03% 91
+
+If you intend to run only on FAT (or if using AnyDBM_File on FAT),
+run Configure with the -Ui_ndbm and -Ui_dbm options to prevent
+NDBM_File and ODBM_File being built.
+
+With NTFS (and no CYGWIN=nontsec), there should be no problems even if
+perl was built on FAT.
+
+=head2 C<fork()> failures in io_* tests
+
+A C<fork()> failure may result in the following tests failing:
+
+ ext/IO/lib/IO/t/io_multihomed.t
+ ext/IO/lib/IO/t/io_sock.t
+ ext/IO/lib/IO/t/io_unix.t
+
+See comment on fork in L<Miscellaneous> below.
+
+=head1 Specific features of the Cygwin port
+
+=head2 Script Portability on Cygwin
+
+Cygwin does an outstanding job of providing UNIX-like semantics on top of
+Win32 systems. However, in addition to the items noted above, there are
+some differences that you should know about. This is a very brief guide
+to portability, more information can be found in the Cygwin documentation.
+
+=over 4
+
+=item * Pathnames
+
+Cygwin pathnames can be separated by forward (F</>) or backward (F<\\>)
+slashes. They may also begin with drive letters (F<C:>) or Universal
+Naming Codes (F<//UNC>). DOS device names (F<aux>, F<con>, F<prn>,
+F<com*>, F<lpt?>, F<nul>) are invalid as base filenames. However, they
+can be used in extensions (e.g., F<hello.aux>). Names may contain all
+printable characters except these:
+
+ : * ? " < > |
+
+File names are case insensitive, but case preserving. A pathname that
+contains a backslash or drive letter is a Win32 pathname (and not subject
+to the translations applied to POSIX style pathnames).
+
+For conversion we have C<Cygwin::win_to_posix_path()> and
+C<Cygwin::posix_to_win_path()>.
+
+Pathnames may not contain Unicode characters. C<Cygwin> still uses the
+ANSI API calls and no Unicode calls because of newlib deficiencies.
+There's an unofficial unicode patch for cygwin at
+F<http://www.okisoft.co.jp/esc/utf8-cygwin/>
+
+=item * Text/Binary
+
+When a file is opened it is in either text or binary mode. In text mode
+a file is subject to CR/LF/Ctrl-Z translations. With Cygwin, the default
+mode for an C<open()> is determined by the mode of the mount that underlies
+the file. See C<Cygwin::is_binmount()>. Perl provides a C<binmode()> function
+to set binary mode on files that otherwise would be treated as text.
+C<sysopen()> with the C<O_TEXT> flag sets text mode on files that otherwise
+would be treated as binary:
+
+ sysopen(FOO, "bar", O_WRONLY|O_CREAT|O_TEXT)
+
+C<lseek()>, C<tell()> and C<sysseek()> only work with files opened in binary
+mode.
+
+The text/binary issue is covered at length in the Cygwin documentation.
+
+=item * PerlIO
+
+PerlIO overrides the default Cygwin Text/Binary behaviour. A file will
+always be treated as binary, regardless of the mode of the mount it lives
+on, just like it is in UNIX. So CR/LF translation needs to be requested in
+either the C<open()> call like this:
+
+ open(FH, ">:crlf", "out.txt");
+
+which will do conversion from LF to CR/LF on the output, or in the
+environment settings (add this to your .bashrc):
+
+ export PERLIO=crlf
+
+which will pull in the crlf PerlIO layer which does LF -> CRLF conversion
+on every output generated by perl.
+
+=item * F<.exe>
+
+The Cygwin C<stat()>, C<lstat()> and C<readlink()> functions make the F<.exe>
+extension transparent by looking for F<foo.exe> when you ask for F<foo>
+(unless a F<foo> also exists). Cygwin does not require a F<.exe>
+extension, but I<gcc> adds it automatically when building a program.
+However, when accessing an executable as a normal file (e.g., I<cp>
+in a makefile) the F<.exe> is not transparent. The I<install> included
+with Cygwin automatically appends a F<.exe> when necessary.
+
+=item * Cygwin vs. Windows process ids
+
+Cygwin processes have their own pid, which is different from the
+underlying windows pid. Most posix compliant Proc functions expect
+the cygwin pid, but several Win32::Process functions expect the
+winpid. E.g. C<$$> is the cygwin pid of F</usr/bin/perl>, which is not
+the winpid. Use C<Cygwin::winpid_to_pid()> and C<Cygwin::winpid_to_pid()>
+to translate between them.
+
+=item * Cygwin vs. Windows errors
+
+Under Cygwin, $^E is the same as $!. When using L<Win32 API Functions|Win32>,
+use C<Win32::GetLastError()> to get the last Windows error.
+
+=item * C<chown()>
+
+On WinNT C<chown()> can change a file's user and group IDs. On Win9x C<chown()>
+is a no-op, although this is appropriate since there is no security model.
+
+=item * Miscellaneous
+
+File locking using the C<F_GETLK> command to C<fcntl()> is a stub that
+returns C<ENOSYS>.
+
+Win9x can not C<rename()> an open file (although WinNT can).
+
+The Cygwin C<chroot()> implementation has holes (it can not restrict file
+access by native Win32 programs).
+
+Inplace editing C<perl -i> of files doesn't work without doing a backup
+of the file being edited C<perl -i.bak> because of windowish restrictions,
+therefore Perl adds the suffix C<.bak> automatically if you use C<perl -i>
+without specifying a backup extension.
+
+Using C<fork()> after loading multiple dlls may fail with an internal cygwin
+error like the following:
+
+ C:\CYGWIN\BIN\PERL.EXE: *** couldn't allocate memory 0x10000(4128768) for 'C:\CYGWIN\LIB\PERL5\5.6.1\CYGWIN-MULTI\AUTO\SOCKET\SOCKET.DLL' alignment, Win32 error 8
+
+ 200 [main] perl 377147 sync_with_child: child -395691(0xB8) died before initialization with status code 0x1
+ 1370 [main] perl 377147 sync_with_child: *** child state child loading dlls
+
+Use the rebase utility to resolve the conflicting dll addresses. The
+rebase package is included in the Cygwin netrelease. Use setup.exe from
+F<http://www.cygwin.com/setup.exe> to install it and run rebaseall.
+
+=back
+
+=head2 Prebuilt methods:
+
+=over 4
+
+=item C<Cwd::cwd>
+
+Returns the current working directory.
+
+=item C<Cygwin::pid_to_winpid>
+
+Translates a cygwin pid to the corresponding Windows pid (which may or
+may not be the same).
+
+=item C<Cygwin::winpid_to_pid>
+
+Translates a Windows pid to the corresponding cygwin pid (if any).
+
+=item C<Cygwin::win_to_posix_path>
+
+Translates a Windows path to the corresponding cygwin path respecting
+the current mount points. With a second non-null argument returns an
+absolute path. Double-byte characters will not be translated.
+
+=item C<Cygwin::posix_to_win_path>
+
+Translates a cygwin path to the corresponding cygwin path respecting
+the current mount points. With a second non-null argument returns an
+absolute path. Double-byte characters will not be translated.
+
+=item C<Cygwin::mount_table()>
+
+Returns an array of [mnt_dir, mnt_fsname, mnt_type, mnt_opts].
+
+ perl -e 'for $i (Cygwin::mount_table) {print join(" ",@$i),"\n";}'
+ /bin c:\cygwin\bin system binmode,cygexec
+ /usr/bin c:\cygwin\bin system binmode
+ /usr/lib c:\cygwin\lib system binmode
+ / c:\cygwin system binmode
+ /cygdrive/c c: system binmode,noumount
+ /cygdrive/d d: system binmode,noumount
+ /cygdrive/e e: system binmode,noumount
+
+=item C<Cygwin::mount_flags>
+
+Returns the mount type and flags for a specified mount point.
+A comma-separated string of mntent->mnt_type (always
+"system" or "user"), then the mntent->mnt_opts, where
+the first is always "binmode" or "textmode".
+
+ system|user,binmode|textmode,exec,cygexec,cygdrive,mixed,
+ notexec,managed,nosuid,devfs,proc,noumount
+
+If the argument is "/cygdrive", then just the volume mount settings,
+and the cygdrive mount prefix are returned.
+
+User mounts override system mounts.
+
+ $ perl -e 'print Cygwin::mount_flags "/usr/bin"'
+ system,binmode,cygexec
+ $ perl -e 'print Cygwin::mount_flags "/cygdrive"'
+ binmode,cygdrive,/cygdrive
+
+=item C<Cygwin::is_binmount>
+
+Returns true if the given cygwin path is binary mounted, false if the
+path is mounted in textmode.
+
+=back
+
+=head1 INSTALL PERL ON CYGWIN
+
+This will install Perl, including I<man> pages.
+
+ make install 2>&1 | tee log.make-install
+
+NOTE: If C<STDERR> is redirected C<make install> will B<not> prompt
+you to install I<perl> into F</usr/bin>.
+
+You may need to be I<Administrator> to run C<make install>. If you
+are not, you must have write access to the directories in question.
+
+Information on installing the Perl documentation in HTML format can be
+found in the F<INSTALL> document.
+
+=head1 MANIFEST ON CYGWIN
+
+These are the files in the Perl release that contain references to Cygwin.
+These very brief notes attempt to explain the reason for all conditional
+code. Hopefully, keeping this up to date will allow the Cygwin port to
+be kept as clean as possible.
+
+=over 4
+
+=item Documentation
+
+ INSTALL README.cygwin README.win32 MANIFEST
+ pod/perl.pod pod/perlport.pod pod/perlfaq3.pod
+ pod/perldelta.pod pod/perl5004delta.pod pod/perl56delta.pod
+ pod/perl561delta.pod pod/perl570delta.pod pod/perl572delta.pod
+ pod/perl573delta.pod pod/perl58delta.pod pod/perl581delta.pod
+ pod/perl590delta.pod pod/perlhist.pod pod/perlmodlib.pod
+ pod/perltoc.pod pod.lst Porting/Glossary pod/perlrepository.pod
+ Porting/checkAUTHORS.pl
+ ext/Compress-Raw-Zlib/Changes ext/Compress-Raw-Zlib/README
+ ext/Compress-Zlib/Changes cpan/Cwd/Changes ext/DB_File/Changes
+ ext/Encode/Changes ext/Sys-Syslog/Changes ext/Time-HiRes/Changes
+ ext/Win32API-File/Changes lib/CGI/Changes lib/ExtUtils/CBuilder/Changes
+ lib/ExtUtils/Changes lib/ExtUtils/NOTES lib/ExtUtils/PATCHING
+ lib/ExtUtils/README lib/Module/Build/Changes lib/Net/Ping/Changes
+ lib/Test/Harness/Changes
+ lib/Term/ANSIColor/ChangeLog lib/Term/ANSIColor/README
+ README.symbian symbian/TODO
+
+=item Build, Configure, Make, Install
+
+ cygwin/Makefile.SHs
+ ext/IPC/SysV/hints/cygwin.pl
+ ext/NDBM_File/hints/cygwin.pl
+ ext/ODBM_File/hints/cygwin.pl
+ hints/cygwin.sh
+ Configure - help finding hints from uname,
+ shared libperl required for dynamic loading
+ Makefile.SH Cross/Makefile-cross-SH
+ - linklibperl
+ Porting/patchls - cygwin in port list
+ installman - man pages with :: translated to .
+ installperl - install dll, install to 'pods'
+ makedepend.SH - uwinfix
+ regen_lib.pl - file permissions
+
+ NetWare/Makefile
+ plan9/mkfile
+ symbian/sanity.pl symbian/sisify.pl
+ hints/uwin.sh
+ vms/descrip_mms.template
+ win32/Makefile win32/makefile.mk
+
+=item Tests
+
+ t/io/fs.t - no file mode checks if not ntsec
+ skip rename() check when not check_case:relaxed
+ t/io/tell.t - binmode
+ t/lib/cygwin.t - builtin cygwin function tests
+ t/op/groups.t - basegroup has ID = 0
+ t/op/magic.t - $^X/symlink WORKAROUND, s/.exe//
+ t/op/stat.t - no /dev, skip Win32 ftCreationTime quirk
+ (cache manager sometimes preserves ctime of file
+ previously created and deleted), no -u (setuid)
+ t/op/taint.t - can't use empty path under Cygwin Perl
+ t/op/time.t - no tzset()
+
+=item Compiled Perl Source
+
+ EXTERN.h - __declspec(dllimport)
+ XSUB.h - __declspec(dllexport)
+ cygwin/cygwin.c - os_extras (getcwd, spawn, and several Cygwin:: functions)
+ perl.c - os_extras, -i.bak
+ perl.h - binmode
+ doio.c - win9x can not rename a file when it is open
+ pp_sys.c - do not define h_errno, init _pwent_struct.pw_comment
+ util.c - use setenv
+ util.h - PERL_FILE_IS_ABSOLUTE macro
+ pp.c - Comment about Posix vs IEEE math under Cygwin
+ perlio.c - CR/LF mode
+ perliol.c - Comment about EXTCONST under Cygwin
+
+=item Compiled Module Source
+
+ ext/Compress-Raw-Zlib/Makefile.PL
+ - Can't install via CPAN shell under Cygwin
+ ext/Compress-Raw-Zlib/zlib-src/zutil.h
+ - Cygwin is Unix-like and has vsnprintf
+ ext/Errno/Errno_pm.PL - Special handling for Win32 Perl under Cygwin
+ ext/POSIX/POSIX.xs - tzname defined externally
+ ext/SDBM_File/sdbm/pair.c
+ - EXTCONST needs to be redefined from EXTERN.h
+ ext/SDBM_File/sdbm/sdbm.c
+ - binary open
+ ext/Sys/Syslog/Syslog.xs
+ - Cygwin has syslog.h
+ ext/Sys/Syslog/win32/compile.pl
+ - Convert paths to Windows paths
+ ext/Time-HiRes/HiRes.xs
+ - Various timers not available
+ ext/Time-HiRes/Makefile.PL
+ - Find w32api/windows.h
+ ext/Win32/Makefile.PL - Use various libraries under Cygwin
+ ext/Win32/Win32.xs - Child dir and child env under Cygwin
+ ext/Win32API-File/File.xs
+ - _open_osfhandle not implemented under Cygwin
+ ext/Win32CORE/Win32CORE.c
+ - __declspec(dllexport)
+
+=item Perl Modules/Scripts
+
+ ext/B/t/OptreeCheck.pm - Comment about stderr/stdout order under Cygwin
+ ext/Digest-SHA/bin/shasum
+ - Use binary mode under Cygwin
+ ext/Sys/Syslog/win32/Win32.pm
+ - Convert paths to Windows paths
+ ext/Time-HiRes/HiRes.pm
+ - Comment about various timers not available
+ ext/Win32API-File/File.pm
+ - _open_osfhandle not implemented under Cygwin
+ ext/Win32CORE/Win32CORE.pm
+ - History of Win32CORE under Cygwin
+ lib/CGI.pm - binmode and path separator
+ lib/CPANPLUS/Dist/MM.pm - Commented out code that fails under Win32/Cygwin
+ lib/CPANPLUS/Internals/Constants/Report.pm
+ - OS classifications
+ lib/CPANPLUS/Internals/Constants.pm
+ - Contants for Cygwin
+ lib/CPANPLUS/Internals/Report.pm
+ - Example of Cygwin report
+ lib/CPANPLUS/Module.pm
+ - Abort if running on old Cygwin version
+ lib/Cwd.pm - hook to internal Cwd::cwd
+ lib/ExtUtils/CBuilder/Platform/cygwin.pm
+ - use gcc for ld, and link to libperl.dll.a
+ lib/ExtUtils/CBuilder.pm
+ - Cygwin is Unix-like
+ lib/ExtUtils/Install.pm - Install and rename issues under Cygwin
+ lib/ExtUtils/MM.pm - OS classifications
+ lib/ExtUtils/MM_Any.pm - Example for Cygwin
+ lib/ExtUtils/MakeMaker.pm
+ - require MM_Cygwin.pm
+ lib/ExtUtils/MM_Cygwin.pm
+ - canonpath, cflags, manifypods, perl_archive
+ lib/File/Fetch.pm - Comment about quotes using a Cygwin example
+ lib/File/Find.pm - on remote drives stat() always sets st_nlink to 1
+ lib/File/Spec/Cygwin.pm - case_tolerant
+ lib/File/Spec/Unix.pm - preserve //unc
+ lib/File/Spec/Win32.pm - References a message on cygwin.com
+ lib/File/Spec.pm - Pulls in lib/File/Spec/Cygwin.pm
+ lib/File/Temp.pm - no directory sticky bit
+ lib/Module/Build/Compat.pm - Comment references 'make' under Cygwin
+ lib/Module/Build/Platform/cygwin.pm
+ - Use '.' for man page separator
+ lib/Module/Build.pm - Cygwin is Unix-like
+ lib/Module/CoreList.pm - List of all module files and versions
+ lib/Net/Domain.pm - No domainname command under Cygwin
+ lib/Net/Netrc.pm - Bypass using stat() under Cygwin
+ lib/Net/Ping.pm - ECONREFUSED is EAGAIN under Cygwin
+ lib/Pod/Find.pm - Set 'pods' dir
+ lib/Pod/Perldoc/ToMan.pm - '-c' switch for pod2man
+ lib/Pod/Perldoc.pm - Use 'less' pager, and use .exe extension
+ lib/Term/ANSIColor.pm - Cygwin terminal info
+ lib/perl5db.pl - use stdin not /dev/tty
+ utils/perlbug.PL - Add CYGWIN environment variable to report
+
+=item Perl Module Tests
+
+ ext/Compress-Zlib/t/14gzopen.t
+ cpan/Cwd/t/cwd.t
+ ext/DB_File/t/db-btree.t
+ ext/DB_File/t/db-hash.t
+ ext/DB_File/t/db-recno.t
+ ext/DynaLoader/t/DynaLoader.t
+ ext/File-Glob/t/basic.t
+ ext/GDBM_File/t/gdbm.t
+ ext/POSIX/t/sysconf.t
+ ext/POSIX/t/time.t
+ ext/SDBM_File/t/sdbm.t
+ ext/Sys/Syslog/t/syslog.t
+ ext/Time-HiRes/t/HiRes.t
+ ext/Win32/t/Unicode.t
+ ext/Win32API-File/t/file.t
+ ext/Win32CORE/t/win32core.t
+ lib/AnyDBM_File.t
+ lib/Archive/Extract/t/01_Archive-Extract.t
+ lib/Archive/Tar/t/02_methods.t
+ lib/CPANPLUS/t/05_CPANPLUS-Internals-Fetch.t
+ lib/CPANPLUS/t/20_CPANPLUS-Dist-MM.t
+ lib/ExtUtils/t/Embed.t
+ lib/ExtUtils/t/eu_command.t
+ lib/ExtUtils/t/MM_Cygwin.t
+ lib/ExtUtils/t/MM_Unix.t
+ lib/File/Compare.t
+ lib/File/Copy.t
+ lib/File/Find/t/find.t
+ lib/File/Path.t
+ lib/File/Spec/t/crossplatform.t
+ lib/File/Spec/t/Spec.t
+ lib/Module/Build/t/destinations.t
+ lib/Net/hostent.t
+ lib/Net/Ping/t/110_icmp_inst.t
+ lib/Net/Ping/t/500_ping_icmp.t
+ lib/Net/t/netrc.t
+ lib/Pod/Simple/t/perlcyg.pod
+ lib/Pod/Simple/t/perlcygo.txt
+ lib/Pod/Simple/t/perlfaq.pod
+ lib/Pod/Simple/t/perlfaqo.txt
+ lib/User/grent.t
+ lib/User/pwent.t
+
+=back
+
+=head1 BUGS ON CYGWIN
+
+Support for swapping real and effective user and group IDs is incomplete.
+On WinNT Cygwin provides C<setuid()>, C<seteuid()>, C<setgid()> and C<setegid()>.
+However, additional Cygwin calls for manipulating WinNT access tokens
+and security contexts are required.
+
+=head1 AUTHORS
+
+Charles Wilson <cwilson@ece.gatech.edu>,
+Eric Fifer <egf7@columbia.edu>,
+alexander smishlajev <als@turnhere.com>,
+Steven Morlock <newspost@morlock.net>,
+Sebastien Barre <Sebastien.Barre@utc.fr>,
+Teun Burgers <burgers@ecn.nl>,
+Gerrit P. Haase <gp@familiehaase.de>,
+Reini Urban <rurban@cpan.org>,
+Jan Dubois <jand@activestate.com>,
+Jerry D. Hedden <jdhedden@cpan.org>.
+
+=head1 HISTORY
+
+Last updated: 2007-09-25
diff --git a/Master/tlpkg/tlperl/lib/pods/perldata.pod b/Master/tlpkg/tlperl/lib/pods/perldata.pod
new file mode 100644
index 00000000000..bc564e650d4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldata.pod
@@ -0,0 +1,867 @@
+=head1 NAME
+
+perldata - Perl data types
+
+=head1 DESCRIPTION
+
+=head2 Variable names
+X<variable, name> X<variable name> X<data type> X<type>
+
+Perl has three built-in data types: scalars, arrays of scalars, and
+associative arrays of scalars, known as "hashes". A scalar is a
+single string (of any size, limited only by the available memory),
+number, or a reference to something (which will be discussed
+in L<perlref>). Normal arrays are ordered lists of scalars indexed
+by number, starting with 0. Hashes are unordered collections of scalar
+values indexed by their associated string key.
+
+Values are usually referred to by name, or through a named reference.
+The first character of the name tells you to what sort of data
+structure it refers. The rest of the name tells you the particular
+value to which it refers. Usually this name is a single I<identifier>,
+that is, a string beginning with a letter or underscore, and
+containing letters, underscores, and digits. In some cases, it may
+be a chain of identifiers, separated by C<::> (or by the slightly
+archaic C<'>); all but the last are interpreted as names of packages,
+to locate the namespace in which to look up the final identifier
+(see L<perlmod/Packages> for details). It's possible to substitute
+for a simple identifier, an expression that produces a reference
+to the value at runtime. This is described in more detail below
+and in L<perlref>.
+X<identifier>
+
+Perl also has its own built-in variables whose names don't follow
+these rules. They have strange names so they don't accidentally
+collide with one of your normal variables. Strings that match
+parenthesized parts of a regular expression are saved under names
+containing only digits after the C<$> (see L<perlop> and L<perlre>).
+In addition, several special variables that provide windows into
+the inner working of Perl have names containing punctuation characters
+and control characters. These are documented in L<perlvar>.
+X<variable, built-in>
+
+Scalar values are always named with '$', even when referring to a
+scalar that is part of an array or a hash. The '$' symbol works
+semantically like the English word "the" in that it indicates a
+single value is expected.
+X<scalar>
+
+ $days # the simple scalar value "days"
+ $days[28] # the 29th element of array @days
+ $days{'Feb'} # the 'Feb' value from hash %days
+ $#days # the last index of array @days
+
+Entire arrays (and slices of arrays and hashes) are denoted by '@',
+which works much like the word "these" or "those" does in English,
+in that it indicates multiple values are expected.
+X<array>
+
+ @days # ($days[0], $days[1],... $days[n])
+ @days[3,4,5] # same as ($days[3],$days[4],$days[5])
+ @days{'a','c'} # same as ($days{'a'},$days{'c'})
+
+Entire hashes are denoted by '%':
+X<hash>
+
+ %days # (key1, val1, key2, val2 ...)
+
+In addition, subroutines are named with an initial '&', though this
+is optional when unambiguous, just as the word "do" is often redundant
+in English. Symbol table entries can be named with an initial '*',
+but you don't really care about that yet (if ever :-).
+
+Every variable type has its own namespace, as do several
+non-variable identifiers. This means that you can, without fear
+of conflict, use the same name for a scalar variable, an array, or
+a hash--or, for that matter, for a filehandle, a directory handle, a
+subroutine name, a format name, or a label. This means that $foo
+and @foo are two different variables. It also means that C<$foo[1]>
+is a part of @foo, not a part of $foo. This may seem a bit weird,
+but that's okay, because it is weird.
+X<namespace>
+
+Because variable references always start with '$', '@', or '%', the
+"reserved" words aren't in fact reserved with respect to variable
+names. They I<are> reserved with respect to labels and filehandles,
+however, which don't have an initial special character. You can't
+have a filehandle named "log", for instance. Hint: you could say
+C<open(LOG,'logfile')> rather than C<open(log,'logfile')>. Using
+uppercase filehandles also improves readability and protects you
+from conflict with future reserved words. Case I<is> significant--"FOO",
+"Foo", and "foo" are all different names. Names that start with a
+letter or underscore may also contain digits and underscores.
+X<identifier, case sensitivity>
+X<case>
+
+It is possible to replace such an alphanumeric name with an expression
+that returns a reference to the appropriate type. For a description
+of this, see L<perlref>.
+
+Names that start with a digit may contain only more digits. Names
+that do not start with a letter, underscore, digit or a caret (i.e.
+a control character) are limited to one character, e.g., C<$%> or
+C<$$>. (Most of these one character names have a predefined
+significance to Perl. For instance, C<$$> is the current process
+id.)
+
+=head2 Context
+X<context> X<scalar context> X<list context>
+
+The interpretation of operations and values in Perl sometimes depends
+on the requirements of the context around the operation or value.
+There are two major contexts: list and scalar. Certain operations
+return list values in contexts wanting a list, and scalar values
+otherwise. If this is true of an operation it will be mentioned in
+the documentation for that operation. In other words, Perl overloads
+certain operations based on whether the expected return value is
+singular or plural. Some words in English work this way, like "fish"
+and "sheep".
+
+In a reciprocal fashion, an operation provides either a scalar or a
+list context to each of its arguments. For example, if you say
+
+ int( <STDIN> )
+
+the integer operation provides scalar context for the <>
+operator, which responds by reading one line from STDIN and passing it
+back to the integer operation, which will then find the integer value
+of that line and return that. If, on the other hand, you say
+
+ sort( <STDIN> )
+
+then the sort operation provides list context for <>, which
+will proceed to read every line available up to the end of file, and
+pass that list of lines back to the sort routine, which will then
+sort those lines and return them as a list to whatever the context
+of the sort was.
+
+Assignment is a little bit special in that it uses its left argument
+to determine the context for the right argument. Assignment to a
+scalar evaluates the right-hand side in scalar context, while
+assignment to an array or hash evaluates the righthand side in list
+context. Assignment to a list (or slice, which is just a list
+anyway) also evaluates the righthand side in list context.
+
+When you use the C<use warnings> pragma or Perl's B<-w> command-line
+option, you may see warnings
+about useless uses of constants or functions in "void context".
+Void context just means the value has been discarded, such as a
+statement containing only C<"fred";> or C<getpwuid(0);>. It still
+counts as scalar context for functions that care whether or not
+they're being called in list context.
+
+User-defined subroutines may choose to care whether they are being
+called in a void, scalar, or list context. Most subroutines do not
+need to bother, though. That's because both scalars and lists are
+automatically interpolated into lists. See L<perlfunc/wantarray>
+for how you would dynamically discern your function's calling
+context.
+
+=head2 Scalar values
+X<scalar> X<number> X<string> X<reference>
+
+All data in Perl is a scalar, an array of scalars, or a hash of
+scalars. A scalar may contain one single value in any of three
+different flavors: a number, a string, or a reference. In general,
+conversion from one form to another is transparent. Although a
+scalar may not directly hold multiple values, it may contain a
+reference to an array or hash which in turn contains multiple values.
+
+Scalars aren't necessarily one thing or another. There's no place
+to declare a scalar variable to be of type "string", type "number",
+type "reference", or anything else. Because of the automatic
+conversion of scalars, operations that return scalars don't need
+to care (and in fact, cannot care) whether their caller is looking
+for a string, a number, or a reference. Perl is a contextually
+polymorphic language whose scalars can be strings, numbers, or
+references (which includes objects). Although strings and numbers
+are considered pretty much the same thing for nearly all purposes,
+references are strongly-typed, uncastable pointers with builtin
+reference-counting and destructor invocation.
+
+A scalar value is interpreted as TRUE in the Boolean sense if it is not
+the null string or the number 0 (or its string equivalent, "0"). The
+Boolean context is just a special kind of scalar context where no
+conversion to a string or a number is ever performed.
+X<boolean> X<bool> X<true> X<false> X<truth>
+
+There are actually two varieties of null strings (sometimes referred
+to as "empty" strings), a defined one and an undefined one. The
+defined version is just a string of length zero, such as C<"">.
+The undefined version is the value that indicates that there is
+no real value for something, such as when there was an error, or
+at end of file, or when you refer to an uninitialized variable or
+element of an array or hash. Although in early versions of Perl,
+an undefined scalar could become defined when first used in a
+place expecting a defined value, this no longer happens except for
+rare cases of autovivification as explained in L<perlref>. You can
+use the defined() operator to determine whether a scalar value is
+defined (this has no meaning on arrays or hashes), and the undef()
+operator to produce an undefined value.
+X<defined> X<undefined> X<undef> X<null> X<string, null>
+
+To find out whether a given string is a valid non-zero number, it's
+sometimes enough to test it against both numeric 0 and also lexical
+"0" (although this will cause noises if warnings are on). That's
+because strings that aren't numbers count as 0, just as they do in B<awk>:
+
+ if ($str == 0 && $str ne "0") {
+ warn "That doesn't look like a number";
+ }
+
+That method may be best because otherwise you won't treat IEEE
+notations like C<NaN> or C<Infinity> properly. At other times, you
+might prefer to determine whether string data can be used numerically
+by calling the POSIX::strtod() function or by inspecting your string
+with a regular expression (as documented in L<perlre>).
+
+ warn "has nondigits" if /\D/;
+ warn "not a natural number" unless /^\d+$/; # rejects -3
+ warn "not an integer" unless /^-?\d+$/; # rejects +3
+ warn "not an integer" unless /^[+-]?\d+$/;
+ warn "not a decimal number" unless /^-?\d+\.?\d*$/; # rejects .2
+ warn "not a decimal number" unless /^-?(?:\d+(?:\.\d*)?|\.\d+)$/;
+ warn "not a C float"
+ unless /^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/;
+
+The length of an array is a scalar value. You may find the length
+of array @days by evaluating C<$#days>, as in B<csh>. However, this
+isn't the length of the array; it's the subscript of the last element,
+which is a different value since there is ordinarily a 0th element.
+Assigning to C<$#days> actually changes the length of the array.
+Shortening an array this way destroys intervening values. Lengthening
+an array that was previously shortened does not recover values
+that were in those elements. (It used to do so in Perl 4, but we
+had to break this to make sure destructors were called when expected.)
+X<$#> X<array, length>
+
+You can also gain some minuscule measure of efficiency by pre-extending
+an array that is going to get big. You can also extend an array
+by assigning to an element that is off the end of the array. You
+can truncate an array down to nothing by assigning the null list
+() to it. The following are equivalent:
+
+ @whatever = ();
+ $#whatever = -1;
+
+If you evaluate an array in scalar context, it returns the length
+of the array. (Note that this is not true of lists, which return
+the last value, like the C comma operator, nor of built-in functions,
+which return whatever they feel like returning.) The following is
+always true:
+X<array, length>
+
+ scalar(@whatever) == $#whatever - $[ + 1;
+
+Version 5 of Perl changed the semantics of C<$[>: files that don't set
+the value of C<$[> no longer need to worry about whether another
+file changed its value. (In other words, use of C<$[> is deprecated.)
+So in general you can assume that
+X<$[>
+
+ scalar(@whatever) == $#whatever + 1;
+
+Some programmers choose to use an explicit conversion so as to
+leave nothing to doubt:
+
+ $element_count = scalar(@whatever);
+
+If you evaluate a hash in scalar context, it returns false if the
+hash is empty. If there are any key/value pairs, it returns true;
+more precisely, the value returned is a string consisting of the
+number of used buckets and the number of allocated buckets, separated
+by a slash. This is pretty much useful only to find out whether
+Perl's internal hashing algorithm is performing poorly on your data
+set. For example, you stick 10,000 things in a hash, but evaluating
+%HASH in scalar context reveals C<"1/16">, which means only one out
+of sixteen buckets has been touched, and presumably contains all
+10,000 of your items. This isn't supposed to happen. If a tied hash
+is evaluated in scalar context, a fatal error will result, since this
+bucket usage information is currently not available for tied hashes.
+X<hash, scalar context> X<hash, bucket> X<bucket>
+
+You can preallocate space for a hash by assigning to the keys() function.
+This rounds up the allocated buckets to the next power of two:
+
+ keys(%users) = 1000; # allocate 1024 buckets
+
+=head2 Scalar value constructors
+X<scalar, literal> X<scalar, constant>
+
+Numeric literals are specified in any of the following floating point or
+integer formats:
+
+ 12345
+ 12345.67
+ .23E-10 # a very small number
+ 3.14_15_92 # a very important number
+ 4_294_967_296 # underscore for legibility
+ 0xff # hex
+ 0xdead_beef # more hex
+ 0377 # octal (only numbers, begins with 0)
+ 0b011011 # binary
+
+You are allowed to use underscores (underbars) in numeric literals
+between digits for legibility. You could, for example, group binary
+digits by threes (as for a Unix-style mode argument such as 0b110_100_100)
+or by fours (to represent nibbles, as in 0b1010_0110) or in other groups.
+X<number, literal>
+
+String literals are usually delimited by either single or double
+quotes. They work much like quotes in the standard Unix shells:
+double-quoted string literals are subject to backslash and variable
+substitution; single-quoted strings are not (except for C<\'> and
+C<\\>). The usual C-style backslash rules apply for making
+characters such as newline, tab, etc., as well as some more exotic
+forms. See L<perlop/"Quote and Quote-like Operators"> for a list.
+X<string, literal>
+
+Hexadecimal, octal, or binary, representations in string literals
+(e.g. '0xff') are not automatically converted to their integer
+representation. The hex() and oct() functions make these conversions
+for you. See L<perlfunc/hex> and L<perlfunc/oct> for more details.
+
+You can also embed newlines directly in your strings, i.e., they can end
+on a different line than they begin. This is nice, but if you forget
+your trailing quote, the error will not be reported until Perl finds
+another line containing the quote character, which may be much further
+on in the script. Variable substitution inside strings is limited to
+scalar variables, arrays, and array or hash slices. (In other words,
+names beginning with $ or @, followed by an optional bracketed
+expression as a subscript.) The following code segment prints out "The
+price is $Z<>100."
+X<interpolation>
+
+ $Price = '$100'; # not interpolated
+ print "The price is $Price.\n"; # interpolated
+
+There is no double interpolation in Perl, so the C<$100> is left as is.
+
+By default floating point numbers substituted inside strings use the
+dot (".") as the decimal separator. If C<use locale> is in effect,
+and POSIX::setlocale() has been called, the character used for the
+decimal separator is affected by the LC_NUMERIC locale.
+See L<perllocale> and L<POSIX>.
+
+As in some shells, you can enclose the variable name in braces to
+disambiguate it from following alphanumerics (and underscores).
+You must also do
+this when interpolating a variable into a string to separate the
+variable name from a following double-colon or an apostrophe, since
+these would be otherwise treated as a package separator:
+X<interpolation>
+
+ $who = "Larry";
+ print PASSWD "${who}::0:0:Superuser:/:/bin/perl\n";
+ print "We use ${who}speak when ${who}'s here.\n";
+
+Without the braces, Perl would have looked for a $whospeak, a
+C<$who::0>, and a C<$who's> variable. The last two would be the
+$0 and the $s variables in the (presumably) non-existent package
+C<who>.
+
+In fact, an identifier within such curlies is forced to be a string,
+as is any simple identifier within a hash subscript. Neither need
+quoting. Our earlier example, C<$days{'Feb'}> can be written as
+C<$days{Feb}> and the quotes will be assumed automatically. But
+anything more complicated in the subscript will be interpreted as an
+expression. This means for example that C<$version{2.0}++> is
+equivalent to C<$version{2}++>, not to C<$version{'2.0'}++>.
+
+=head3 Version Strings
+X<version string> X<vstring> X<v-string>
+
+A literal of the form C<v1.20.300.4000> is parsed as a string composed
+of characters with the specified ordinals. This form, known as
+v-strings, provides an alternative, more readable way to construct
+strings, rather than use the somewhat less readable interpolation form
+C<"\x{1}\x{14}\x{12c}\x{fa0}">. This is useful for representing
+Unicode strings, and for comparing version "numbers" using the string
+comparison operators, C<cmp>, C<gt>, C<lt> etc. If there are two or
+more dots in the literal, the leading C<v> may be omitted.
+
+ print v9786; # prints SMILEY, "\x{263a}"
+ print v102.111.111; # prints "foo"
+ print 102.111.111; # same
+
+Such literals are accepted by both C<require> and C<use> for
+doing a version check. Note that using the v-strings for IPv4
+addresses is not portable unless you also use the
+inet_aton()/inet_ntoa() routines of the Socket package.
+
+Note that since Perl 5.8.1 the single-number v-strings (like C<v65>)
+are not v-strings before the C<< => >> operator (which is usually used
+to separate a hash key from a hash value), instead they are interpreted
+as literal strings ('v65'). They were v-strings from Perl 5.6.0 to
+Perl 5.8.0, but that caused more confusion and breakage than good.
+Multi-number v-strings like C<v65.66> and C<65.66.67> continue to
+be v-strings always.
+
+=head3 Special Literals
+X<special literal> X<__END__> X<__DATA__> X<END> X<DATA>
+X<end> X<data> X<^D> X<^Z>
+
+The special literals __FILE__, __LINE__, and __PACKAGE__
+represent the current filename, line number, and package name at that
+point in your program. They may be used only as separate tokens; they
+will not be interpolated into strings. If there is no current package
+(due to an empty C<package;> directive), __PACKAGE__ is the undefined
+value.
+X<__FILE__> X<__LINE__> X<__PACKAGE__> X<line> X<file> X<package>
+
+The two control characters ^D and ^Z, and the tokens __END__ and __DATA__
+may be used to indicate the logical end of the script before the actual
+end of file. Any following text is ignored.
+
+Text after __DATA__ may be read via the filehandle C<PACKNAME::DATA>,
+where C<PACKNAME> is the package that was current when the __DATA__
+token was encountered. The filehandle is left open pointing to the
+contents after __DATA__. It is the program's responsibility to
+C<close DATA> when it is done reading from it. For compatibility with
+older scripts written before __DATA__ was introduced, __END__ behaves
+like __DATA__ in the top level script (but not in files loaded with
+C<require> or C<do>) and leaves the remaining contents of the
+file accessible via C<main::DATA>.
+
+See L<SelfLoader> for more description of __DATA__, and
+an example of its use. Note that you cannot read from the DATA
+filehandle in a BEGIN block: the BEGIN block is executed as soon
+as it is seen (during compilation), at which point the corresponding
+__DATA__ (or __END__) token has not yet been seen.
+
+=head3 Barewords
+X<bareword>
+
+A word that has no other interpretation in the grammar will
+be treated as if it were a quoted string. These are known as
+"barewords". As with filehandles and labels, a bareword that consists
+entirely of lowercase letters risks conflict with future reserved
+words, and if you use the C<use warnings> pragma or the B<-w> switch,
+Perl will warn you about any such words. Perl limits barewords (like
+identifiers) to about 250 characters. Future versions of Perl are likely
+to eliminate these arbitrary limitations.
+
+Some people may wish to outlaw barewords entirely. If you
+say
+
+ use strict 'subs';
+
+then any bareword that would NOT be interpreted as a subroutine call
+produces a compile-time error instead. The restriction lasts to the
+end of the enclosing block. An inner block may countermand this
+by saying C<no strict 'subs'>.
+
+=head3 Array Joining Delimiter
+X<array, interpolation> X<interpolation, array> X<$">
+
+Arrays and slices are interpolated into double-quoted strings
+by joining the elements with the delimiter specified in the C<$">
+variable (C<$LIST_SEPARATOR> if "use English;" is specified),
+space by default. The following are equivalent:
+
+ $temp = join($", @ARGV);
+ system "echo $temp";
+
+ system "echo @ARGV";
+
+Within search patterns (which also undergo double-quotish substitution)
+there is an unfortunate ambiguity: Is C</$foo[bar]/> to be interpreted as
+C</${foo}[bar]/> (where C<[bar]> is a character class for the regular
+expression) or as C</${foo[bar]}/> (where C<[bar]> is the subscript to array
+@foo)? If @foo doesn't otherwise exist, then it's obviously a
+character class. If @foo exists, Perl takes a good guess about C<[bar]>,
+and is almost always right. If it does guess wrong, or if you're just
+plain paranoid, you can force the correct interpretation with curly
+braces as above.
+
+If you're looking for the information on how to use here-documents,
+which used to be here, that's been moved to
+L<perlop/Quote and Quote-like Operators>.
+
+=head2 List value constructors
+X<list>
+
+List values are denoted by separating individual values by commas
+(and enclosing the list in parentheses where precedence requires it):
+
+ (LIST)
+
+In a context not requiring a list value, the value of what appears
+to be a list literal is simply the value of the final element, as
+with the C comma operator. For example,
+
+ @foo = ('cc', '-E', $bar);
+
+assigns the entire list value to array @foo, but
+
+ $foo = ('cc', '-E', $bar);
+
+assigns the value of variable $bar to the scalar variable $foo.
+Note that the value of an actual array in scalar context is the
+length of the array; the following assigns the value 3 to $foo:
+
+ @foo = ('cc', '-E', $bar);
+ $foo = @foo; # $foo gets 3
+
+You may have an optional comma before the closing parenthesis of a
+list literal, so that you can say:
+
+ @foo = (
+ 1,
+ 2,
+ 3,
+ );
+
+To use a here-document to assign an array, one line per element,
+you might use an approach like this:
+
+ @sauces = <<End_Lines =~ m/(\S.*\S)/g;
+ normal tomato
+ spicy tomato
+ green chile
+ pesto
+ white wine
+ End_Lines
+
+LISTs do automatic interpolation of sublists. That is, when a LIST is
+evaluated, each element of the list is evaluated in list context, and
+the resulting list value is interpolated into LIST just as if each
+individual element were a member of LIST. Thus arrays and hashes lose their
+identity in a LIST--the list
+
+ (@foo,@bar,&SomeSub,%glarch)
+
+contains all the elements of @foo followed by all the elements of @bar,
+followed by all the elements returned by the subroutine named SomeSub
+called in list context, followed by the key/value pairs of %glarch.
+To make a list reference that does I<NOT> interpolate, see L<perlref>.
+
+The null list is represented by (). Interpolating it in a list
+has no effect. Thus ((),(),()) is equivalent to (). Similarly,
+interpolating an array with no elements is the same as if no
+array had been interpolated at that point.
+
+This interpolation combines with the facts that the opening
+and closing parentheses are optional (except when necessary for
+precedence) and lists may end with an optional comma to mean that
+multiple commas within lists are legal syntax. The list C<1,,3> is a
+concatenation of two lists, C<1,> and C<3>, the first of which ends
+with that optional comma. C<1,,3> is C<(1,),(3)> is C<1,3> (And
+similarly for C<1,,,3> is C<(1,),(,),3> is C<1,3> and so on.) Not that
+we'd advise you to use this obfuscation.
+
+A list value may also be subscripted like a normal array. You must
+put the list in parentheses to avoid ambiguity. For example:
+
+ # Stat returns list value.
+ $time = (stat($file))[8];
+
+ # SYNTAX ERROR HERE.
+ $time = stat($file)[8]; # OOPS, FORGOT PARENTHESES
+
+ # Find a hex digit.
+ $hexdigit = ('a','b','c','d','e','f')[$digit-10];
+
+ # A "reverse comma operator".
+ return (pop(@foo),pop(@foo))[0];
+
+Lists may be assigned to only when each element of the list
+is itself legal to assign to:
+
+ ($a, $b, $c) = (1, 2, 3);
+
+ ($map{'red'}, $map{'blue'}, $map{'green'}) = (0x00f, 0x0f0, 0xf00);
+
+An exception to this is that you may assign to C<undef> in a list.
+This is useful for throwing away some of the return values of a
+function:
+
+ ($dev, $ino, undef, undef, $uid, $gid) = stat($file);
+
+List assignment in scalar context returns the number of elements
+produced by the expression on the right side of the assignment:
+
+ $x = (($foo,$bar) = (3,2,1)); # set $x to 3, not 2
+ $x = (($foo,$bar) = f()); # set $x to f()'s return count
+
+This is handy when you want to do a list assignment in a Boolean
+context, because most list functions return a null list when finished,
+which when assigned produces a 0, which is interpreted as FALSE.
+
+It's also the source of a useful idiom for executing a function or
+performing an operation in list context and then counting the number of
+return values, by assigning to an empty list and then using that
+assignment in scalar context. For example, this code:
+
+ $count = () = $string =~ /\d+/g;
+
+will place into $count the number of digit groups found in $string.
+This happens because the pattern match is in list context (since it
+is being assigned to the empty list), and will therefore return a list
+of all matching parts of the string. The list assignment in scalar
+context will translate that into the number of elements (here, the
+number of times the pattern matched) and assign that to $count. Note
+that simply using
+
+ $count = $string =~ /\d+/g;
+
+would not have worked, since a pattern match in scalar context will
+only return true or false, rather than a count of matches.
+
+The final element of a list assignment may be an array or a hash:
+
+ ($a, $b, @rest) = split;
+ my($a, $b, %rest) = @_;
+
+You can actually put an array or hash anywhere in the list, but the first one
+in the list will soak up all the values, and anything after it will become
+undefined. This may be useful in a my() or local().
+
+A hash can be initialized using a literal list holding pairs of
+items to be interpreted as a key and a value:
+
+ # same as map assignment above
+ %map = ('red',0x00f,'blue',0x0f0,'green',0xf00);
+
+While literal lists and named arrays are often interchangeable, that's
+not the case for hashes. Just because you can subscript a list value like
+a normal array does not mean that you can subscript a list value as a
+hash. Likewise, hashes included as parts of other lists (including
+parameters lists and return lists from functions) always flatten out into
+key/value pairs. That's why it's good to use references sometimes.
+
+It is often more readable to use the C<< => >> operator between key/value
+pairs. The C<< => >> operator is mostly just a more visually distinctive
+synonym for a comma, but it also arranges for its left-hand operand to be
+interpreted as a string if it's a bareword that would be a legal simple
+identifier. C<< => >> doesn't quote compound identifiers, that contain
+double colons. This makes it nice for initializing hashes:
+
+ %map = (
+ red => 0x00f,
+ blue => 0x0f0,
+ green => 0xf00,
+ );
+
+or for initializing hash references to be used as records:
+
+ $rec = {
+ witch => 'Mable the Merciless',
+ cat => 'Fluffy the Ferocious',
+ date => '10/31/1776',
+ };
+
+or for using call-by-named-parameter to complicated functions:
+
+ $field = $query->radio_group(
+ name => 'group_name',
+ values => ['eenie','meenie','minie'],
+ default => 'meenie',
+ linebreak => 'true',
+ labels => \%labels
+ );
+
+Note that just because a hash is initialized in that order doesn't
+mean that it comes out in that order. See L<perlfunc/sort> for examples
+of how to arrange for an output ordering.
+
+=head2 Subscripts
+
+An array is subscripted by specifying a dollar sign (C<$>), then the
+name of the array (without the leading C<@>), then the subscript inside
+square brackets. For example:
+
+ @myarray = (5, 50, 500, 5000);
+ print "The Third Element is", $myarray[2], "\n";
+
+The array indices start with 0. A negative subscript retrieves its
+value from the end. In our example, C<$myarray[-1]> would have been
+5000, and C<$myarray[-2]> would have been 500.
+
+Hash subscripts are similar, only instead of square brackets curly brackets
+are used. For example:
+
+ %scientists =
+ (
+ "Newton" => "Isaac",
+ "Einstein" => "Albert",
+ "Darwin" => "Charles",
+ "Feynman" => "Richard",
+ );
+
+ print "Darwin's First Name is ", $scientists{"Darwin"}, "\n";
+
+=head2 Slices
+X<slice> X<array, slice> X<hash, slice>
+
+A common way to access an array or a hash is one scalar element at a
+time. You can also subscript a list to get a single element from it.
+
+ $whoami = $ENV{"USER"}; # one element from the hash
+ $parent = $ISA[0]; # one element from the array
+ $dir = (getpwnam("daemon"))[7]; # likewise, but with list
+
+A slice accesses several elements of a list, an array, or a hash
+simultaneously using a list of subscripts. It's more convenient
+than writing out the individual elements as a list of separate
+scalar values.
+
+ ($him, $her) = @folks[0,-1]; # array slice
+ @them = @folks[0 .. 3]; # array slice
+ ($who, $home) = @ENV{"USER", "HOME"}; # hash slice
+ ($uid, $dir) = (getpwnam("daemon"))[2,7]; # list slice
+
+Since you can assign to a list of variables, you can also assign to
+an array or hash slice.
+
+ @days[3..5] = qw/Wed Thu Fri/;
+ @colors{'red','blue','green'}
+ = (0xff0000, 0x0000ff, 0x00ff00);
+ @folks[0, -1] = @folks[-1, 0];
+
+The previous assignments are exactly equivalent to
+
+ ($days[3], $days[4], $days[5]) = qw/Wed Thu Fri/;
+ ($colors{'red'}, $colors{'blue'}, $colors{'green'})
+ = (0xff0000, 0x0000ff, 0x00ff00);
+ ($folks[0], $folks[-1]) = ($folks[-1], $folks[0]);
+
+Since changing a slice changes the original array or hash that it's
+slicing, a C<foreach> construct will alter some--or even all--of the
+values of the array or hash.
+
+ foreach (@array[ 4 .. 10 ]) { s/peter/paul/ }
+
+ foreach (@hash{qw[key1 key2]}) {
+ s/^\s+//; # trim leading whitespace
+ s/\s+$//; # trim trailing whitespace
+ s/(\w+)/\u\L$1/g; # "titlecase" words
+ }
+
+A slice of an empty list is still an empty list. Thus:
+
+ @a = ()[1,0]; # @a has no elements
+ @b = (@a)[0,1]; # @b has no elements
+ @c = (0,1)[2,3]; # @c has no elements
+
+But:
+
+ @a = (1)[1,0]; # @a has two elements
+ @b = (1,undef)[1,0,2]; # @b has three elements
+
+This makes it easy to write loops that terminate when a null list
+is returned:
+
+ while ( ($home, $user) = (getpwent)[7,0]) {
+ printf "%-8s %s\n", $user, $home;
+ }
+
+As noted earlier in this document, the scalar sense of list assignment
+is the number of elements on the right-hand side of the assignment.
+The null list contains no elements, so when the password file is
+exhausted, the result is 0, not 2.
+
+If you're confused about why you use an '@' there on a hash slice
+instead of a '%', think of it like this. The type of bracket (square
+or curly) governs whether it's an array or a hash being looked at.
+On the other hand, the leading symbol ('$' or '@') on the array or
+hash indicates whether you are getting back a singular value (a
+scalar) or a plural one (a list).
+
+=head2 Typeglobs and Filehandles
+X<typeglob> X<filehandle> X<*>
+
+Perl uses an internal type called a I<typeglob> to hold an entire
+symbol table entry. The type prefix of a typeglob is a C<*>, because
+it represents all types. This used to be the preferred way to
+pass arrays and hashes by reference into a function, but now that
+we have real references, this is seldom needed.
+
+The main use of typeglobs in modern Perl is create symbol table aliases.
+This assignment:
+
+ *this = *that;
+
+makes $this an alias for $that, @this an alias for @that, %this an alias
+for %that, &this an alias for &that, etc. Much safer is to use a reference.
+This:
+
+ local *Here::blue = \$There::green;
+
+temporarily makes $Here::blue an alias for $There::green, but doesn't
+make @Here::blue an alias for @There::green, or %Here::blue an alias for
+%There::green, etc. See L<perlmod/"Symbol Tables"> for more examples
+of this. Strange though this may seem, this is the basis for the whole
+module import/export system.
+
+Another use for typeglobs is to pass filehandles into a function or
+to create new filehandles. If you need to use a typeglob to save away
+a filehandle, do it this way:
+
+ $fh = *STDOUT;
+
+or perhaps as a real reference, like this:
+
+ $fh = \*STDOUT;
+
+See L<perlsub> for examples of using these as indirect filehandles
+in functions.
+
+Typeglobs are also a way to create a local filehandle using the local()
+operator. These last until their block is exited, but may be passed back.
+For example:
+
+ sub newopen {
+ my $path = shift;
+ local *FH; # not my!
+ open (FH, $path) or return undef;
+ return *FH;
+ }
+ $fh = newopen('/etc/passwd');
+
+Now that we have the C<*foo{THING}> notation, typeglobs aren't used as much
+for filehandle manipulations, although they're still needed to pass brand
+new file and directory handles into or out of functions. That's because
+C<*HANDLE{IO}> only works if HANDLE has already been used as a handle.
+In other words, C<*FH> must be used to create new symbol table entries;
+C<*foo{THING}> cannot. When in doubt, use C<*FH>.
+
+All functions that are capable of creating filehandles (open(),
+opendir(), pipe(), socketpair(), sysopen(), socket(), and accept())
+automatically create an anonymous filehandle if the handle passed to
+them is an uninitialized scalar variable. This allows the constructs
+such as C<open(my $fh, ...)> and C<open(local $fh,...)> to be used to
+create filehandles that will conveniently be closed automatically when
+the scope ends, provided there are no other references to them. This
+largely eliminates the need for typeglobs when opening filehandles
+that must be passed around, as in the following example:
+
+ sub myopen {
+ open my $fh, "@_"
+ or die "Can't open '@_': $!";
+ return $fh;
+ }
+
+ {
+ my $f = myopen("</etc/motd");
+ print <$f>;
+ # $f implicitly closed here
+ }
+
+Note that if an initialized scalar variable is used instead the
+result is different: C<my $fh='zzz'; open($fh, ...)> is equivalent
+to C<open( *{'zzz'}, ...)>.
+C<use strict 'refs'> forbids such practice.
+
+Another way to create anonymous filehandles is with the Symbol
+module or with the IO::Handle module and its ilk. These modules
+have the advantage of not hiding different types of the same name
+during the local(). See the bottom of L<perlfunc/open()> for an
+example.
+
+=head1 SEE ALSO
+
+See L<perlvar> for a description of Perl's built-in variables and
+a discussion of legal variable names. See L<perlref>, L<perlsub>,
+and L<perlmod/"Symbol Tables"> for more discussion on typeglobs and
+the C<*foo{THING}> syntax.
diff --git a/Master/tlpkg/tlperl/lib/pods/perldbmfilter.pod b/Master/tlpkg/tlperl/lib/pods/perldbmfilter.pod
new file mode 100644
index 00000000000..e58ce2013be
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldbmfilter.pod
@@ -0,0 +1,168 @@
+=head1 NAME
+
+perldbmfilter - Perl DBM Filters
+
+=head1 SYNOPSIS
+
+ $db = tie %hash, 'DBM', ...
+
+ $old_filter = $db->filter_store_key ( sub { ... } );
+ $old_filter = $db->filter_store_value( sub { ... } );
+ $old_filter = $db->filter_fetch_key ( sub { ... } );
+ $old_filter = $db->filter_fetch_value( sub { ... } );
+
+=head1 DESCRIPTION
+
+The four C<filter_*> methods shown above are available in all the DBM
+modules that ship with Perl, namely DB_File, GDBM_File, NDBM_File,
+ODBM_File and SDBM_File.
+
+Each of the methods work identically, and are used to install (or
+uninstall) a single DBM Filter. The only difference between them is the
+place that the filter is installed.
+
+To summarise:
+
+=over 5
+
+=item B<filter_store_key>
+
+If a filter has been installed with this method, it will be invoked
+every time you write a key to a DBM database.
+
+=item B<filter_store_value>
+
+If a filter has been installed with this method, it will be invoked
+every time you write a value to a DBM database.
+
+
+=item B<filter_fetch_key>
+
+If a filter has been installed with this method, it will be invoked
+every time you read a key from a DBM database.
+
+=item B<filter_fetch_value>
+
+If a filter has been installed with this method, it will be invoked
+every time you read a value from a DBM database.
+
+=back
+
+You can use any combination of the methods from none to all four.
+
+All filter methods return the existing filter, if present, or C<undef>
+in not.
+
+To delete a filter pass C<undef> to it.
+
+=head2 The Filter
+
+When each filter is called by Perl, a local copy of C<$_> will contain
+the key or value to be filtered. Filtering is achieved by modifying
+the contents of C<$_>. The return code from the filter is ignored.
+
+=head2 An Example: the NULL termination problem.
+
+DBM Filters are useful for a class of problems where you I<always>
+want to make the same transformation to all keys, all values or both.
+
+For example, consider the following scenario. You have a DBM database
+that you need to share with a third-party C application. The C application
+assumes that I<all> keys and values are NULL terminated. Unfortunately
+when Perl writes to DBM databases it doesn't use NULL termination, so
+your Perl application will have to manage NULL termination itself. When
+you write to the database you will have to use something like this:
+
+ $hash{"$key\0"} = "$value\0";
+
+Similarly the NULL needs to be taken into account when you are considering
+the length of existing keys/values.
+
+It would be much better if you could ignore the NULL terminations issue
+in the main application code and have a mechanism that automatically
+added the terminating NULL to all keys and values whenever you write to
+the database and have them removed when you read from the database. As I'm
+sure you have already guessed, this is a problem that DBM Filters can
+fix very easily.
+
+ use strict;
+ use warnings;
+ use SDBM_File;
+ use Fcntl;
+
+ my %hash;
+ my $filename = "filt";
+ unlink $filename;
+
+ my $db = tie(%hash, 'SDBM_File', $filename, O_RDWR|O_CREAT, 0640)
+ or die "Cannot open $filename: $!\n";
+
+ # Install DBM Filters
+ $db->filter_fetch_key ( sub { s/\0$// } );
+ $db->filter_store_key ( sub { $_ .= "\0" } );
+ $db->filter_fetch_value(
+ sub { no warnings 'uninitialized'; s/\0$// } );
+ $db->filter_store_value( sub { $_ .= "\0" } );
+
+ $hash{"abc"} = "def";
+ my $a = $hash{"ABC"};
+ # ...
+ undef $db;
+ untie %hash;
+
+The code above uses SDBM_File, but it will work with any of the DBM
+modules.
+
+Hopefully the contents of each of the filters should be
+self-explanatory. Both "fetch" filters remove the terminating NULL,
+and both "store" filters add a terminating NULL.
+
+
+=head2 Another Example: Key is a C int.
+
+Here is another real-life example. By default, whenever Perl writes to
+a DBM database it always writes the key and value as strings. So when
+you use this:
+
+ $hash{12345} = "something";
+
+the key 12345 will get stored in the DBM database as the 5 byte string
+"12345". If you actually want the key to be stored in the DBM database
+as a C int, you will have to use C<pack> when writing, and C<unpack>
+when reading.
+
+Here is a DBM Filter that does it:
+
+ use strict;
+ use warnings;
+ use DB_File;
+ my %hash;
+ my $filename = "filt";
+ unlink $filename;
+
+
+ my $db = tie %hash, 'DB_File', $filename, O_CREAT|O_RDWR, 0666, $DB_HASH
+ or die "Cannot open $filename: $!\n";
+
+ $db->filter_fetch_key ( sub { $_ = unpack("i", $_) } );
+ $db->filter_store_key ( sub { $_ = pack ("i", $_) } );
+ $hash{123} = "def";
+ # ...
+ undef $db;
+ untie %hash;
+
+The code above uses DB_File, but again it will work with any of the
+DBM modules.
+
+This time only two filters have been used; we only need to manipulate
+the contents of the key, so it wasn't necessary to install any value
+filters.
+
+=head1 SEE ALSO
+
+L<DB_File>, L<GDBM_File>, L<NDBM_File>, L<ODBM_File> and L<SDBM_File>.
+
+=head1 AUTHOR
+
+Paul Marquess
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perldebguts.pod b/Master/tlpkg/tlperl/lib/pods/perldebguts.pod
new file mode 100644
index 00000000000..402b67c242f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldebguts.pod
@@ -0,0 +1,879 @@
+=head1 NAME
+
+perldebguts - Guts of Perl debugging
+
+=head1 DESCRIPTION
+
+This is not L<perldebug>, which tells you how to use
+the debugger. This manpage describes low-level details concerning
+the debugger's internals, which range from difficult to impossible
+to understand for anyone who isn't incredibly intimate with Perl's guts.
+Caveat lector.
+
+=head1 Debugger Internals
+
+Perl has special debugging hooks at compile-time and run-time used
+to create debugging environments. These hooks are not to be confused
+with the I<perl -Dxxx> command described in L<perlrun>, which is
+usable only if a special Perl is built per the instructions in the
+F<INSTALL> podpage in the Perl source tree.
+
+For example, whenever you call Perl's built-in C<caller> function
+from the package C<DB>, the arguments that the corresponding stack
+frame was called with are copied to the C<@DB::args> array. These
+mechanisms are enabled by calling Perl with the B<-d> switch.
+Specifically, the following additional features are enabled
+(cf. L<perlvar/$^P>):
+
+=over 4
+
+=item *
+
+Perl inserts the contents of C<$ENV{PERL5DB}> (or C<BEGIN {require
+'perl5db.pl'}> if not present) before the first line of your program.
+
+=item *
+
+Each array C<@{"_<$filename"}> holds the lines of $filename for a
+file compiled by Perl. The same is also true for C<eval>ed strings
+that contain subroutines, or which are currently being executed.
+The $filename for C<eval>ed strings looks like C<(eval 34)>.
+Code assertions in regexes look like C<(re_eval 19)>.
+
+Values in this array are magical in numeric context: they compare
+equal to zero only if the line is not breakable.
+
+=item *
+
+Each hash C<%{"_<$filename"}> contains breakpoints and actions keyed
+by line number. Individual entries (as opposed to the whole hash)
+are settable. Perl only cares about Boolean true here, although
+the values used by F<perl5db.pl> have the form
+C<"$break_condition\0$action">.
+
+The same holds for evaluated strings that contain subroutines, or
+which are currently being executed. The $filename for C<eval>ed strings
+looks like C<(eval 34)> or C<(re_eval 19)>.
+
+=item *
+
+Each scalar C<${"_<$filename"}> contains C<"_<$filename">. This is
+also the case for evaluated strings that contain subroutines, or
+which are currently being executed. The $filename for C<eval>ed
+strings looks like C<(eval 34)> or C<(re_eval 19)>.
+
+=item *
+
+After each C<require>d file is compiled, but before it is executed,
+C<DB::postponed(*{"_<$filename"})> is called if the subroutine
+C<DB::postponed> exists. Here, the $filename is the expanded name of
+the C<require>d file, as found in the values of %INC.
+
+=item *
+
+After each subroutine C<subname> is compiled, the existence of
+C<$DB::postponed{subname}> is checked. If this key exists,
+C<DB::postponed(subname)> is called if the C<DB::postponed> subroutine
+also exists.
+
+=item *
+
+A hash C<%DB::sub> is maintained, whose keys are subroutine names
+and whose values have the form C<filename:startline-endline>.
+C<filename> has the form C<(eval 34)> for subroutines defined inside
+C<eval>s, or C<(re_eval 19)> for those within regex code assertions.
+
+=item *
+
+When the execution of your program reaches a point that can hold a
+breakpoint, the C<DB::DB()> subroutine is called if any of the variables
+C<$DB::trace>, C<$DB::single>, or C<$DB::signal> is true. These variables
+are not C<local>izable. This feature is disabled when executing
+inside C<DB::DB()>, including functions called from it
+unless C<< $^D & (1<<30) >> is true.
+
+=item *
+
+When execution of the program reaches a subroutine call, a call to
+C<&DB::sub>(I<args>) is made instead, with C<$DB::sub> holding the
+name of the called subroutine. (This doesn't happen if the subroutine
+was compiled in the C<DB> package.)
+
+=back
+
+Note that if C<&DB::sub> needs external data for it to work, no
+subroutine call is possible without it. As an example, the standard
+debugger's C<&DB::sub> depends on the C<$DB::deep> variable
+(it defines how many levels of recursion deep into the debugger you can go
+before a mandatory break). If C<$DB::deep> is not defined, subroutine
+calls are not possible, even though C<&DB::sub> exists.
+
+=head2 Writing Your Own Debugger
+
+=head3 Environment Variables
+
+The C<PERL5DB> environment variable can be used to define a debugger.
+For example, the minimal "working" debugger (it actually doesn't do anything)
+consists of one line:
+
+ sub DB::DB {}
+
+It can easily be defined like this:
+
+ $ PERL5DB="sub DB::DB {}" perl -d your-script
+
+Another brief debugger, slightly more useful, can be created
+with only the line:
+
+ sub DB::DB {print ++$i; scalar <STDIN>}
+
+This debugger prints a number which increments for each statement
+encountered and waits for you to hit a newline before continuing
+to the next statement.
+
+The following debugger is actually useful:
+
+ {
+ package DB;
+ sub DB {}
+ sub sub {print ++$i, " $sub\n"; &$sub}
+ }
+
+It prints the sequence number of each subroutine call and the name of the
+called subroutine. Note that C<&DB::sub> is being compiled into the
+package C<DB> through the use of the C<package> directive.
+
+When it starts, the debugger reads your rc file (F<./.perldb> or
+F<~/.perldb> under Unix), which can set important options.
+(A subroutine (C<&afterinit>) can be defined here as well; it is executed
+after the debugger completes its own initialization.)
+
+After the rc file is read, the debugger reads the PERLDB_OPTS
+environment variable and uses it to set debugger options. The
+contents of this variable are treated as if they were the argument
+of an C<o ...> debugger command (q.v. in L<perldebug/Options>).
+
+=head3 Debugger internal variables
+
+In addition to the file and subroutine-related variables mentioned above,
+the debugger also maintains various magical internal variables.
+
+=over 4
+
+=item *
+
+C<@DB::dbline> is an alias for C<@{"::_<current_file"}>, which
+holds the lines of the currently-selected file (compiled by Perl), either
+explicitly chosen with the debugger's C<f> command, or implicitly by flow
+of execution.
+
+Values in this array are magical in numeric context: they compare
+equal to zero only if the line is not breakable.
+
+=item *
+
+C<%DB::dbline>, is an alias for C<%{"::_<current_file"}>, which
+contains breakpoints and actions keyed by line number in
+the currently-selected file, either explicitly chosen with the
+debugger's C<f> command, or implicitly by flow of execution.
+
+As previously noted, individual entries (as opposed to the whole hash)
+are settable. Perl only cares about Boolean true here, although
+the values used by F<perl5db.pl> have the form
+C<"$break_condition\0$action">.
+
+=back
+
+=head3 Debugger customization functions
+
+Some functions are provided to simplify customization.
+
+=over 4
+
+=item *
+
+See L<perldebug/"Configurable Options"> for a description of options parsed by
+C<DB::parse_options(string)>.
+
+=item *
+
+C<DB::dump_trace(skip[,count])> skips the specified number of frames
+and returns a list containing information about the calling frames (all
+of them, if C<count> is missing). Each entry is reference to a hash
+with keys C<context> (either C<.>, C<$>, or C<@>), C<sub> (subroutine
+name, or info about C<eval>), C<args> (C<undef> or a reference to
+an array), C<file>, and C<line>.
+
+=item *
+
+C<DB::print_trace(FH, skip[, count[, short]])> prints
+formatted info about caller frames. The last two functions may be
+convenient as arguments to C<< < >>, C<< << >> commands.
+
+=back
+
+Note that any variables and functions that are not documented in
+this manpages (or in L<perldebug>) are considered for internal
+use only, and as such are subject to change without notice.
+
+=head1 Frame Listing Output Examples
+
+The C<frame> option can be used to control the output of frame
+information. For example, contrast this expression trace:
+
+ $ perl -de 42
+ Stack dump during die enabled outside of evals.
+
+ Loading DB routines from perl5db.pl patch level 0.94
+ Emacs support available.
+
+ Enter h or `h h' for help.
+
+ main::(-e:1): 0
+ DB<1> sub foo { 14 }
+
+ DB<2> sub bar { 3 }
+
+ DB<3> t print foo() * bar()
+ main::((eval 172):3): print foo() + bar();
+ main::foo((eval 168):2):
+ main::bar((eval 170):2):
+ 42
+
+with this one, once the C<o>ption C<frame=2> has been set:
+
+ DB<4> o f=2
+ frame = '2'
+ DB<5> t print foo() * bar()
+ 3: foo() * bar()
+ entering main::foo
+ 2: sub foo { 14 };
+ exited main::foo
+ entering main::bar
+ 2: sub bar { 3 };
+ exited main::bar
+ 42
+
+By way of demonstration, we present below a laborious listing
+resulting from setting your C<PERLDB_OPTS> environment variable to
+the value C<f=n N>, and running I<perl -d -V> from the command line.
+Examples use various values of C<n> are shown to give you a feel
+for the difference between settings. Long those it may be, this
+is not a complete listing, but only excerpts.
+
+=over 4
+
+=item 1
+
+ entering main::BEGIN
+ entering Config::BEGIN
+ Package lib/Exporter.pm.
+ Package lib/Carp.pm.
+ Package lib/Config.pm.
+ entering Config::TIEHASH
+ entering Exporter::import
+ entering Exporter::export
+ entering Config::myconfig
+ entering Config::FETCH
+ entering Config::FETCH
+ entering Config::FETCH
+ entering Config::FETCH
+
+=item 2
+
+ entering main::BEGIN
+ entering Config::BEGIN
+ Package lib/Exporter.pm.
+ Package lib/Carp.pm.
+ exited Config::BEGIN
+ Package lib/Config.pm.
+ entering Config::TIEHASH
+ exited Config::TIEHASH
+ entering Exporter::import
+ entering Exporter::export
+ exited Exporter::export
+ exited Exporter::import
+ exited main::BEGIN
+ entering Config::myconfig
+ entering Config::FETCH
+ exited Config::FETCH
+ entering Config::FETCH
+ exited Config::FETCH
+ entering Config::FETCH
+
+=item 3
+
+ in $=main::BEGIN() from /dev/null:0
+ in $=Config::BEGIN() from lib/Config.pm:2
+ Package lib/Exporter.pm.
+ Package lib/Carp.pm.
+ Package lib/Config.pm.
+ in $=Config::TIEHASH('Config') from lib/Config.pm:644
+ in $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ in $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from li
+ in @=Config::myconfig() from /dev/null:0
+ in $=Config::FETCH(ref(Config), 'package') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'baserev') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'PERL_VERSION') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'PERL_SUBVERSION') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'osname') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'osvers') from lib/Config.pm:574
+
+=item 4
+
+ in $=main::BEGIN() from /dev/null:0
+ in $=Config::BEGIN() from lib/Config.pm:2
+ Package lib/Exporter.pm.
+ Package lib/Carp.pm.
+ out $=Config::BEGIN() from lib/Config.pm:0
+ Package lib/Config.pm.
+ in $=Config::TIEHASH('Config') from lib/Config.pm:644
+ out $=Config::TIEHASH('Config') from lib/Config.pm:644
+ in $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ in $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/
+ out $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/
+ out $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ out $=main::BEGIN() from /dev/null:0
+ in @=Config::myconfig() from /dev/null:0
+ in $=Config::FETCH(ref(Config), 'package') from lib/Config.pm:574
+ out $=Config::FETCH(ref(Config), 'package') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'baserev') from lib/Config.pm:574
+ out $=Config::FETCH(ref(Config), 'baserev') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'PERL_VERSION') from lib/Config.pm:574
+ out $=Config::FETCH(ref(Config), 'PERL_VERSION') from lib/Config.pm:574
+ in $=Config::FETCH(ref(Config), 'PERL_SUBVERSION') from lib/Config.pm:574
+
+=item 5
+
+ in $=main::BEGIN() from /dev/null:0
+ in $=Config::BEGIN() from lib/Config.pm:2
+ Package lib/Exporter.pm.
+ Package lib/Carp.pm.
+ out $=Config::BEGIN() from lib/Config.pm:0
+ Package lib/Config.pm.
+ in $=Config::TIEHASH('Config') from lib/Config.pm:644
+ out $=Config::TIEHASH('Config') from lib/Config.pm:644
+ in $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ in $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/E
+ out $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/E
+ out $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ out $=main::BEGIN() from /dev/null:0
+ in @=Config::myconfig() from /dev/null:0
+ in $=Config::FETCH('Config=HASH(0x1aa444)', 'package') from lib/Config.pm:574
+ out $=Config::FETCH('Config=HASH(0x1aa444)', 'package') from lib/Config.pm:574
+ in $=Config::FETCH('Config=HASH(0x1aa444)', 'baserev') from lib/Config.pm:574
+ out $=Config::FETCH('Config=HASH(0x1aa444)', 'baserev') from lib/Config.pm:574
+
+=item 6
+
+ in $=CODE(0x15eca4)() from /dev/null:0
+ in $=CODE(0x182528)() from lib/Config.pm:2
+ Package lib/Exporter.pm.
+ out $=CODE(0x182528)() from lib/Config.pm:0
+ scalar context return from CODE(0x182528): undef
+ Package lib/Config.pm.
+ in $=Config::TIEHASH('Config') from lib/Config.pm:628
+ out $=Config::TIEHASH('Config') from lib/Config.pm:628
+ scalar context return from Config::TIEHASH: empty hash
+ in $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ in $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/Exporter.pm:171
+ out $=Exporter::export('Config', 'main', 'myconfig', 'config_vars') from lib/Exporter.pm:171
+ scalar context return from Exporter::export: ''
+ out $=Exporter::import('Config', 'myconfig', 'config_vars') from /dev/null:0
+ scalar context return from Exporter::import: ''
+
+=back
+
+In all cases shown above, the line indentation shows the call tree.
+If bit 2 of C<frame> is set, a line is printed on exit from a
+subroutine as well. If bit 4 is set, the arguments are printed
+along with the caller info. If bit 8 is set, the arguments are
+printed even if they are tied or references. If bit 16 is set, the
+return value is printed, too.
+
+When a package is compiled, a line like this
+
+ Package lib/Carp.pm.
+
+is printed with proper indentation.
+
+=head1 Debugging regular expressions
+
+There are two ways to enable debugging output for regular expressions.
+
+If your perl is compiled with C<-DDEBUGGING>, you may use the
+B<-Dr> flag on the command line.
+
+Otherwise, one can C<use re 'debug'>, which has effects at
+compile time and run time. Since Perl 5.9.5, this pragma is lexically
+scoped.
+
+=head2 Compile-time output
+
+The debugging output at compile time looks like this:
+
+ Compiling REx `[bc]d(ef*g)+h[ij]k$'
+ size 45 Got 364 bytes for offset annotations.
+ first at 1
+ rarest char g at 0
+ rarest char d at 0
+ 1: ANYOF[bc](12)
+ 12: EXACT <d>(14)
+ 14: CURLYX[0] {1,32767}(28)
+ 16: OPEN1(18)
+ 18: EXACT <e>(20)
+ 20: STAR(23)
+ 21: EXACT <f>(0)
+ 23: EXACT <g>(25)
+ 25: CLOSE1(27)
+ 27: WHILEM[1/1](0)
+ 28: NOTHING(29)
+ 29: EXACT <h>(31)
+ 31: ANYOF[ij](42)
+ 42: EXACT <k>(44)
+ 44: EOL(45)
+ 45: END(0)
+ anchored `de' at 1 floating `gh' at 3..2147483647 (checking floating)
+ stclass `ANYOF[bc]' minlen 7
+ Offsets: [45]
+ 1[4] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 5[1]
+ 0[0] 12[1] 0[0] 6[1] 0[0] 7[1] 0[0] 9[1] 8[1] 0[0] 10[1] 0[0]
+ 11[1] 0[0] 12[0] 12[0] 13[1] 0[0] 14[4] 0[0] 0[0] 0[0] 0[0]
+ 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 18[1] 0[0] 19[1] 20[0]
+ Omitting $` $& $' support.
+
+The first line shows the pre-compiled form of the regex. The second
+shows the size of the compiled form (in arbitrary units, usually
+4-byte words) and the total number of bytes allocated for the
+offset/length table, usually 4+C<size>*8. The next line shows the
+label I<id> of the first node that does a match.
+
+The
+
+ anchored `de' at 1 floating `gh' at 3..2147483647 (checking floating)
+ stclass `ANYOF[bc]' minlen 7
+
+line (split into two lines above) contains optimizer
+information. In the example shown, the optimizer found that the match
+should contain a substring C<de> at offset 1, plus substring C<gh>
+at some offset between 3 and infinity. Moreover, when checking for
+these substrings (to abandon impossible matches quickly), Perl will check
+for the substring C<gh> before checking for the substring C<de>. The
+optimizer may also use the knowledge that the match starts (at the
+C<first> I<id>) with a character class, and no string
+shorter than 7 characters can possibly match.
+
+The fields of interest which may appear in this line are
+
+=over 4
+
+=item C<anchored> I<STRING> C<at> I<POS>
+
+=item C<floating> I<STRING> C<at> I<POS1..POS2>
+
+See above.
+
+=item C<matching floating/anchored>
+
+Which substring to check first.
+
+=item C<minlen>
+
+The minimal length of the match.
+
+=item C<stclass> I<TYPE>
+
+Type of first matching node.
+
+=item C<noscan>
+
+Don't scan for the found substrings.
+
+=item C<isall>
+
+Means that the optimizer information is all that the regular
+expression contains, and thus one does not need to enter the regex engine at
+all.
+
+=item C<GPOS>
+
+Set if the pattern contains C<\G>.
+
+=item C<plus>
+
+Set if the pattern starts with a repeated char (as in C<x+y>).
+
+=item C<implicit>
+
+Set if the pattern starts with C<.*>.
+
+=item C<with eval>
+
+Set if the pattern contain eval-groups, such as C<(?{ code })> and
+C<(??{ code })>.
+
+=item C<anchored(TYPE)>
+
+If the pattern may match only at a handful of places, (with C<TYPE>
+being C<BOL>, C<MBOL>, or C<GPOS>. See the table below.
+
+=back
+
+If a substring is known to match at end-of-line only, it may be
+followed by C<$>, as in C<floating `k'$>.
+
+The optimizer-specific information is used to avoid entering (a slow) regex
+engine on strings that will not definitely match. If the C<isall> flag
+is set, a call to the regex engine may be avoided even when the optimizer
+found an appropriate place for the match.
+
+Above the optimizer section is the list of I<nodes> of the compiled
+form of the regex. Each line has format
+
+C< >I<id>: I<TYPE> I<OPTIONAL-INFO> (I<next-id>)
+
+=head2 Types of nodes
+
+Here are the possible types, with short descriptions:
+
+ # TYPE arg-description [num-args] [longjump-len] DESCRIPTION
+
+ # Exit points
+ END no End of program.
+ SUCCEED no Return from a subroutine, basically.
+
+ # Anchors:
+ BOL no Match "" at beginning of line.
+ MBOL no Same, assuming multiline.
+ SBOL no Same, assuming singleline.
+ EOS no Match "" at end of string.
+ EOL no Match "" at end of line.
+ MEOL no Same, assuming multiline.
+ SEOL no Same, assuming singleline.
+ BOUND no Match "" at any word boundary
+ BOUNDL no Match "" at any word boundary
+ NBOUND no Match "" at any word non-boundary
+ NBOUNDL no Match "" at any word non-boundary
+ GPOS no Matches where last m//g left off.
+
+ # [Special] alternatives
+ ANY no Match any one character (except newline).
+ SANY no Match any one character.
+ ANYOF sv Match character in (or not in) this class.
+ ALNUM no Match any alphanumeric character
+ ALNUML no Match any alphanumeric char in locale
+ NALNUM no Match any non-alphanumeric character
+ NALNUML no Match any non-alphanumeric char in locale
+ SPACE no Match any whitespace character
+ SPACEL no Match any whitespace char in locale
+ NSPACE no Match any non-whitespace character
+ NSPACEL no Match any non-whitespace char in locale
+ DIGIT no Match any numeric character
+ NDIGIT no Match any non-numeric character
+
+ # BRANCH The set of branches constituting a single choice are hooked
+ # together with their "next" pointers, since precedence prevents
+ # anything being concatenated to any individual branch. The
+ # "next" pointer of the last BRANCH in a choice points to the
+ # thing following the whole choice. This is also where the
+ # final "next" pointer of each individual branch points; each
+ # branch starts with the operand node of a BRANCH node.
+ #
+ BRANCH node Match this alternative, or the next...
+
+ # BACK Normal "next" pointers all implicitly point forward; BACK
+ # exists to make loop structures possible.
+ # not used
+ BACK no Match "", "next" ptr points backward.
+
+ # Literals
+ EXACT sv Match this string (preceded by length).
+ EXACTF sv Match this string, folded (prec. by length).
+ EXACTFL sv Match this string, folded in locale (w/len).
+
+ # Do nothing
+ NOTHING no Match empty string.
+ # A variant of above which delimits a group, thus stops optimizations
+ TAIL no Match empty string. Can jump here from outside.
+
+ # STAR,PLUS '?', and complex '*' and '+', are implemented as circular
+ # BRANCH structures using BACK. Simple cases (one character
+ # per match) are implemented with STAR and PLUS for speed
+ # and to minimize recursive plunges.
+ #
+ STAR node Match this (simple) thing 0 or more times.
+ PLUS node Match this (simple) thing 1 or more times.
+
+ CURLY sv 2 Match this simple thing {n,m} times.
+ CURLYN no 2 Match next-after-this simple thing
+ # {n,m} times, set parens.
+ CURLYM no 2 Match this medium-complex thing {n,m} times.
+ CURLYX sv 2 Match this complex thing {n,m} times.
+
+ # This terminator creates a loop structure for CURLYX
+ WHILEM no Do curly processing and see if rest matches.
+
+ # OPEN,CLOSE,GROUPP ...are numbered at compile time.
+ OPEN num 1 Mark this point in input as start of #n.
+ CLOSE num 1 Analogous to OPEN.
+
+ REF num 1 Match some already matched string
+ REFF num 1 Match already matched string, folded
+ REFFL num 1 Match already matched string, folded in loc.
+
+ # grouping assertions
+ IFMATCH off 1 2 Succeeds if the following matches.
+ UNLESSM off 1 2 Fails if the following matches.
+ SUSPEND off 1 1 "Independent" sub-regex.
+ IFTHEN off 1 1 Switch, should be preceded by switcher .
+ GROUPP num 1 Whether the group matched.
+
+ # Support for long regex
+ LONGJMP off 1 1 Jump far away.
+ BRANCHJ off 1 1 BRANCH with long offset.
+
+ # The heavy worker
+ EVAL evl 1 Execute some Perl code.
+
+ # Modifiers
+ MINMOD no Next operator is not greedy.
+ LOGICAL no Next opcode should set the flag only.
+
+ # This is not used yet
+ RENUM off 1 1 Group with independently numbered parens.
+
+ # This is not really a node, but an optimized away piece of a "long" node.
+ # To simplify debugging output, we mark it as if it were a node
+ OPTIMIZED off Placeholder for dump.
+
+=for unprinted-credits
+Next section M-J. Dominus (mjd-perl-patch+@plover.com) 20010421
+
+Following the optimizer information is a dump of the offset/length
+table, here split across several lines:
+
+ Offsets: [45]
+ 1[4] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 5[1]
+ 0[0] 12[1] 0[0] 6[1] 0[0] 7[1] 0[0] 9[1] 8[1] 0[0] 10[1] 0[0]
+ 11[1] 0[0] 12[0] 12[0] 13[1] 0[0] 14[4] 0[0] 0[0] 0[0] 0[0]
+ 0[0] 0[0] 0[0] 0[0] 0[0] 0[0] 18[1] 0[0] 19[1] 20[0]
+
+The first line here indicates that the offset/length table contains 45
+entries. Each entry is a pair of integers, denoted by C<offset[length]>.
+Entries are numbered starting with 1, so entry #1 here is C<1[4]> and
+entry #12 is C<5[1]>. C<1[4]> indicates that the node labeled C<1:>
+(the C<1: ANYOF[bc]>) begins at character position 1 in the
+pre-compiled form of the regex, and has a length of 4 characters.
+C<5[1]> in position 12
+indicates that the node labeled C<12:>
+(the C<< 12: EXACT <d> >>) begins at character position 5 in the
+pre-compiled form of the regex, and has a length of 1 character.
+C<12[1]> in position 14
+indicates that the node labeled C<14:>
+(the C<< 14: CURLYX[0] {1,32767} >>) begins at character position 12 in the
+pre-compiled form of the regex, and has a length of 1 character---that
+is, it corresponds to the C<+> symbol in the precompiled regex.
+
+C<0[0]> items indicate that there is no corresponding node.
+
+=head2 Run-time output
+
+First of all, when doing a match, one may get no run-time output even
+if debugging is enabled. This means that the regex engine was never
+entered and that all of the job was therefore done by the optimizer.
+
+If the regex engine was entered, the output may look like this:
+
+ Matching `[bc]d(ef*g)+h[ij]k$' against `abcdefg__gh__'
+ Setting an EVAL scope, savestack=3
+ 2 <ab> <cdefg__gh_> | 1: ANYOF
+ 3 <abc> <defg__gh_> | 11: EXACT <d>
+ 4 <abcd> <efg__gh_> | 13: CURLYX {1,32767}
+ 4 <abcd> <efg__gh_> | 26: WHILEM
+ 0 out of 1..32767 cc=effff31c
+ 4 <abcd> <efg__gh_> | 15: OPEN1
+ 4 <abcd> <efg__gh_> | 17: EXACT <e>
+ 5 <abcde> <fg__gh_> | 19: STAR
+ EXACT <f> can match 1 times out of 32767...
+ Setting an EVAL scope, savestack=3
+ 6 <bcdef> <g__gh__> | 22: EXACT <g>
+ 7 <bcdefg> <__gh__> | 24: CLOSE1
+ 7 <bcdefg> <__gh__> | 26: WHILEM
+ 1 out of 1..32767 cc=effff31c
+ Setting an EVAL scope, savestack=12
+ 7 <bcdefg> <__gh__> | 15: OPEN1
+ 7 <bcdefg> <__gh__> | 17: EXACT <e>
+ restoring \1 to 4(4)..7
+ failed, try continuation...
+ 7 <bcdefg> <__gh__> | 27: NOTHING
+ 7 <bcdefg> <__gh__> | 28: EXACT <h>
+ failed...
+ failed...
+
+The most significant information in the output is about the particular I<node>
+of the compiled regex that is currently being tested against the target string.
+The format of these lines is
+
+C< >I<STRING-OFFSET> <I<PRE-STRING>> <I<POST-STRING>> |I<ID>: I<TYPE>
+
+The I<TYPE> info is indented with respect to the backtracking level.
+Other incidental information appears interspersed within.
+
+=head1 Debugging Perl memory usage
+
+Perl is a profligate wastrel when it comes to memory use. There
+is a saying that to estimate memory usage of Perl, assume a reasonable
+algorithm for memory allocation, multiply that estimate by 10, and
+while you still may miss the mark, at least you won't be quite so
+astonished. This is not absolutely true, but may provide a good
+grasp of what happens.
+
+Assume that an integer cannot take less than 20 bytes of memory, a
+float cannot take less than 24 bytes, a string cannot take less
+than 32 bytes (all these examples assume 32-bit architectures, the
+result are quite a bit worse on 64-bit architectures). If a variable
+is accessed in two of three different ways (which require an integer,
+a float, or a string), the memory footprint may increase yet another
+20 bytes. A sloppy malloc(3) implementation can inflate these
+numbers dramatically.
+
+On the opposite end of the scale, a declaration like
+
+ sub foo;
+
+may take up to 500 bytes of memory, depending on which release of Perl
+you're running.
+
+Anecdotal estimates of source-to-compiled code bloat suggest an
+eightfold increase. This means that the compiled form of reasonable
+(normally commented, properly indented etc.) code will take
+about eight times more space in memory than the code took
+on disk.
+
+The B<-DL> command-line switch is obsolete since circa Perl 5.6.0
+(it was available only if Perl was built with C<-DDEBUGGING>).
+The switch was used to track Perl's memory allocations and possible
+memory leaks. These days the use of malloc debugging tools like
+F<Purify> or F<valgrind> is suggested instead. See also
+L<perlhack/PERL_MEM_LOG>.
+
+One way to find out how much memory is being used by Perl data
+structures is to install the Devel::Size module from CPAN: it gives
+you the minimum number of bytes required to store a particular data
+structure. Please be mindful of the difference between the size()
+and total_size().
+
+If Perl has been compiled using Perl's malloc you can analyze Perl
+memory usage by setting the $ENV{PERL_DEBUG_MSTATS}.
+
+=head2 Using C<$ENV{PERL_DEBUG_MSTATS}>
+
+If your perl is using Perl's malloc() and was compiled with the
+necessary switches (this is the default), then it will print memory
+usage statistics after compiling your code when C<< $ENV{PERL_DEBUG_MSTATS}
+> 1 >>, and before termination of the program when C<<
+$ENV{PERL_DEBUG_MSTATS} >= 1 >>. The report format is similar to
+the following example:
+
+ $ PERL_DEBUG_MSTATS=2 perl -e "require Carp"
+ Memory allocation statistics after compilation: (buckets 4(4)..8188(8192)
+ 14216 free: 130 117 28 7 9 0 2 2 1 0 0
+ 437 61 36 0 5
+ 60924 used: 125 137 161 55 7 8 6 16 2 0 1
+ 74 109 304 84 20
+ Total sbrk(): 77824/21:119. Odd ends: pad+heads+chain+tail: 0+636+0+2048.
+ Memory allocation statistics after execution: (buckets 4(4)..8188(8192)
+ 30888 free: 245 78 85 13 6 2 1 3 2 0 1
+ 315 162 39 42 11
+ 175816 used: 265 176 1112 111 26 22 11 27 2 1 1
+ 196 178 1066 798 39
+ Total sbrk(): 215040/47:145. Odd ends: pad+heads+chain+tail: 0+2192+0+6144.
+
+It is possible to ask for such a statistic at arbitrary points in
+your execution using the mstat() function out of the standard
+Devel::Peek module.
+
+Here is some explanation of that format:
+
+=over 4
+
+=item C<buckets SMALLEST(APPROX)..GREATEST(APPROX)>
+
+Perl's malloc() uses bucketed allocations. Every request is rounded
+up to the closest bucket size available, and a bucket is taken from
+the pool of buckets of that size.
+
+The line above describes the limits of buckets currently in use.
+Each bucket has two sizes: memory footprint and the maximal size
+of user data that can fit into this bucket. Suppose in the above
+example that the smallest bucket were size 4. The biggest bucket
+would have usable size 8188, and the memory footprint would be 8192.
+
+In a Perl built for debugging, some buckets may have negative usable
+size. This means that these buckets cannot (and will not) be used.
+For larger buckets, the memory footprint may be one page greater
+than a power of 2. If so, case the corresponding power of two is
+printed in the C<APPROX> field above.
+
+=item Free/Used
+
+The 1 or 2 rows of numbers following that correspond to the number
+of buckets of each size between C<SMALLEST> and C<GREATEST>. In
+the first row, the sizes (memory footprints) of buckets are powers
+of two--or possibly one page greater. In the second row, if present,
+the memory footprints of the buckets are between the memory footprints
+of two buckets "above".
+
+For example, suppose under the previous example, the memory footprints
+were
+
+ free: 8 16 32 64 128 256 512 1024 2048 4096 8192
+ 4 12 24 48 80
+
+With non-C<DEBUGGING> perl, the buckets starting from C<128> have
+a 4-byte overhead, and thus an 8192-long bucket may take up to
+8188-byte allocations.
+
+=item C<Total sbrk(): SBRKed/SBRKs:CONTINUOUS>
+
+The first two fields give the total amount of memory perl sbrk(2)ed
+(ess-broken? :-) and number of sbrk(2)s used. The third number is
+what perl thinks about continuity of returned chunks. So long as
+this number is positive, malloc() will assume that it is probable
+that sbrk(2) will provide continuous memory.
+
+Memory allocated by external libraries is not counted.
+
+=item C<pad: 0>
+
+The amount of sbrk(2)ed memory needed to keep buckets aligned.
+
+=item C<heads: 2192>
+
+Although memory overhead of bigger buckets is kept inside the bucket, for
+smaller buckets, it is kept in separate areas. This field gives the
+total size of these areas.
+
+=item C<chain: 0>
+
+malloc() may want to subdivide a bigger bucket into smaller buckets.
+If only a part of the deceased bucket is left unsubdivided, the rest
+is kept as an element of a linked list. This field gives the total
+size of these chunks.
+
+=item C<tail: 6144>
+
+To minimize the number of sbrk(2)s, malloc() asks for more memory. This
+field gives the size of the yet unused part, which is sbrk(2)ed, but
+never touched.
+
+=back
+
+=head1 SEE ALSO
+
+L<perldebug>,
+L<perlguts>,
+L<perlrun>
+L<re>,
+and
+L<Devel::DProf>.
diff --git a/Master/tlpkg/tlperl/lib/pods/perldebtut.pod b/Master/tlpkg/tlperl/lib/pods/perldebtut.pod
new file mode 100644
index 00000000000..b10f9b4066e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldebtut.pod
@@ -0,0 +1,723 @@
+=head1 NAME
+
+perldebtut - Perl debugging tutorial
+
+=head1 DESCRIPTION
+
+A (very) lightweight introduction in the use of the perl debugger, and a
+pointer to existing, deeper sources of information on the subject of debugging
+perl programs.
+
+There's an extraordinary number of people out there who don't appear to know
+anything about using the perl debugger, though they use the language every
+day.
+This is for them.
+
+
+=head1 use strict
+
+First of all, there's a few things you can do to make your life a lot more
+straightforward when it comes to debugging perl programs, without using the
+debugger at all. To demonstrate, here's a simple script, named "hello", with
+a problem:
+
+ #!/usr/bin/perl
+
+ $var1 = 'Hello World'; # always wanted to do that :-)
+ $var2 = "$varl\n";
+
+ print $var2;
+ exit;
+
+While this compiles and runs happily, it probably won't do what's expected,
+namely it doesn't print "Hello World\n" at all; It will on the other hand do
+exactly what it was told to do, computers being a bit that way inclined. That
+is, it will print out a newline character, and you'll get what looks like a
+blank line. It looks like there's 2 variables when (because of the typo)
+there's really 3:
+
+ $var1 = 'Hello World';
+ $varl = undef;
+ $var2 = "\n";
+
+To catch this kind of problem, we can force each variable to be declared
+before use by pulling in the strict module, by putting 'use strict;' after the
+first line of the script.
+
+Now when you run it, perl complains about the 3 undeclared variables and we
+get four error messages because one variable is referenced twice:
+
+ Global symbol "$var1" requires explicit package name at ./t1 line 4.
+ Global symbol "$var2" requires explicit package name at ./t1 line 5.
+ Global symbol "$varl" requires explicit package name at ./t1 line 5.
+ Global symbol "$var2" requires explicit package name at ./t1 line 7.
+ Execution of ./hello aborted due to compilation errors.
+
+Luvverly! and to fix this we declare all variables explicitly and now our
+script looks like this:
+
+ #!/usr/bin/perl
+ use strict;
+
+ my $var1 = 'Hello World';
+ my $varl = undef;
+ my $var2 = "$varl\n";
+
+ print $var2;
+ exit;
+
+We then do (always a good idea) a syntax check before we try to run it again:
+
+ > perl -c hello
+ hello syntax OK
+
+And now when we run it, we get "\n" still, but at least we know why. Just
+getting this script to compile has exposed the '$varl' (with the letter 'l')
+variable, and simply changing $varl to $var1 solves the problem.
+
+
+=head1 Looking at data and -w and v
+
+Ok, but how about when you want to really see your data, what's in that
+dynamic variable, just before using it?
+
+ #!/usr/bin/perl
+ use strict;
+
+ my $key = 'welcome';
+ my %data = (
+ 'this' => qw(that),
+ 'tom' => qw(and jerry),
+ 'welcome' => q(Hello World),
+ 'zip' => q(welcome),
+ );
+ my @data = keys %data;
+
+ print "$data{$key}\n";
+ exit;
+
+Looks OK, after it's been through the syntax check (perl -c scriptname), we
+run it and all we get is a blank line again! Hmmmm.
+
+One common debugging approach here, would be to liberally sprinkle a few print
+statements, to add a check just before we print out our data, and another just
+after:
+
+ print "All OK\n" if grep($key, keys %data);
+ print "$data{$key}\n";
+ print "done: '$data{$key}'\n";
+
+And try again:
+
+ > perl data
+ All OK
+
+ done: ''
+
+After much staring at the same piece of code and not seeing the wood for the
+trees for some time, we get a cup of coffee and try another approach. That
+is, we bring in the cavalry by giving perl the 'B<-d>' switch on the command
+line:
+
+ > perl -d data
+ Default die handler restored.
+
+ Loading DB routines from perl5db.pl version 1.07
+ Editor support available.
+
+ Enter h or `h h' for help, or `man perldebug' for more help.
+
+ main::(./data:4): my $key = 'welcome';
+
+Now, what we've done here is to launch the built-in perl debugger on our
+script. It's stopped at the first line of executable code and is waiting for
+input.
+
+Before we go any further, you'll want to know how to quit the debugger: use
+just the letter 'B<q>', not the words 'quit' or 'exit':
+
+ DB<1> q
+ >
+
+That's it, you're back on home turf again.
+
+
+=head1 help
+
+Fire the debugger up again on your script and we'll look at the help menu.
+There's a couple of ways of calling help: a simple 'B<h>' will get the summary
+help list, 'B<|h>' (pipe-h) will pipe the help through your pager (which is
+(probably 'more' or 'less'), and finally, 'B<h h>' (h-space-h) will give you
+the entire help screen. Here is the summary page:
+
+DB<1>h
+
+ List/search source lines: Control script execution:
+ l [ln|sub] List source code T Stack trace
+ - or . List previous/current line s [expr] Single step [in expr]
+ v [line] View around line n [expr] Next, steps over subs
+ f filename View source in file <CR/Enter> Repeat last n or s
+ /pattern/ ?patt? Search forw/backw r Return from subroutine
+ M Show module versions c [ln|sub] Continue until position
+ Debugger controls: L List break/watch/actions
+ o [...] Set debugger options t [expr] Toggle trace [trace expr]
+ <[<]|{[{]|>[>] [cmd] Do pre/post-prompt b [ln|event|sub] [cnd] Set breakpoint
+ ! [N|pat] Redo a previous command B ln|* Delete a/all breakpoints
+ H [-num] Display last num commands a [ln] cmd Do cmd before line
+ = [a val] Define/list an alias A ln|* Delete a/all actions
+ h [db_cmd] Get help on command w expr Add a watch expression
+ h h Complete help page W expr|* Delete a/all watch exprs
+ |[|]db_cmd Send output to pager ![!] syscmd Run cmd in a subprocess
+ q or ^D Quit R Attempt a restart
+ Data Examination: expr Execute perl code, also see: s,n,t expr
+ x|m expr Evals expr in list context, dumps the result or lists methods.
+ p expr Print expression (uses script's current package).
+ S [[!]pat] List subroutine names [not] matching pattern
+ V [Pk [Vars]] List Variables in Package. Vars can be ~pattern or !pattern.
+ X [Vars] Same as "V current_package [Vars]".
+ y [n [Vars]] List lexicals in higher scope <n>. Vars same as V.
+ For more help, type h cmd_letter, or run man perldebug for all docs.
+
+More confusing options than you can shake a big stick at! It's not as bad as
+it looks and it's very useful to know more about all of it, and fun too!
+
+There's a couple of useful ones to know about straight away. You wouldn't
+think we're using any libraries at all at the moment, but 'B<M>' will show
+which modules are currently loaded, and their version number, while 'B<m>'
+will show the methods, and 'B<S>' shows all subroutines (by pattern) as
+shown below. 'B<V>' and 'B<X>' show variables in the program by package
+scope and can be constrained by pattern.
+
+ DB<2>S str
+ dumpvar::stringify
+ strict::bits
+ strict::import
+ strict::unimport
+
+Using 'X' and cousins requires you not to use the type identifiers ($@%), just
+the 'name':
+
+ DM<3>X ~err
+ FileHandle(stderr) => fileno(2)
+
+Remember we're in our tiny program with a problem, we should have a look at
+where we are, and what our data looks like. First of all let's view some code
+at our present position (the first line of code in this case), via 'B<v>':
+
+ DB<4> v
+ 1 #!/usr/bin/perl
+ 2: use strict;
+ 3
+ 4==> my $key = 'welcome';
+ 5: my %data = (
+ 6 'this' => qw(that),
+ 7 'tom' => qw(and jerry),
+ 8 'welcome' => q(Hello World),
+ 9 'zip' => q(welcome),
+ 10 );
+
+At line number 4 is a helpful pointer, that tells you where you are now. To
+see more code, type 'v' again:
+
+ DB<4> v
+ 8 'welcome' => q(Hello World),
+ 9 'zip' => q(welcome),
+ 10 );
+ 11: my @data = keys %data;
+ 12: print "All OK\n" if grep($key, keys %data);
+ 13: print "$data{$key}\n";
+ 14: print "done: '$data{$key}'\n";
+ 15: exit;
+
+And if you wanted to list line 5 again, type 'l 5', (note the space):
+
+ DB<4> l 5
+ 5: my %data = (
+
+In this case, there's not much to see, but of course normally there's pages of
+stuff to wade through, and 'l' can be very useful. To reset your view to the
+line we're about to execute, type a lone period '.':
+
+ DB<5> .
+ main::(./data_a:4): my $key = 'welcome';
+
+The line shown is the one that is about to be executed B<next>, it hasn't
+happened yet. So while we can print a variable with the letter 'B<p>', at
+this point all we'd get is an empty (undefined) value back. What we need to
+do is to step through the next executable statement with an 'B<s>':
+
+ DB<6> s
+ main::(./data_a:5): my %data = (
+ main::(./data_a:6): 'this' => qw(that),
+ main::(./data_a:7): 'tom' => qw(and jerry),
+ main::(./data_a:8): 'welcome' => q(Hello World),
+ main::(./data_a:9): 'zip' => q(welcome),
+ main::(./data_a:10): );
+
+Now we can have a look at that first ($key) variable:
+
+ DB<7> p $key
+ welcome
+
+line 13 is where the action is, so let's continue down to there via the letter
+'B<c>', which by the way, inserts a 'one-time-only' breakpoint at the given
+line or sub routine:
+
+ DB<8> c 13
+ All OK
+ main::(./data_a:13): print "$data{$key}\n";
+
+We've gone past our check (where 'All OK' was printed) and have stopped just
+before the meat of our task. We could try to print out a couple of variables
+to see what is happening:
+
+ DB<9> p $data{$key}
+
+Not much in there, lets have a look at our hash:
+
+ DB<10> p %data
+ Hello Worldziptomandwelcomejerrywelcomethisthat
+
+ DB<11> p keys %data
+ Hello Worldtomwelcomejerrythis
+
+Well, this isn't very easy to read, and using the helpful manual (B<h h>), the
+'B<x>' command looks promising:
+
+ DB<12> x %data
+ 0 'Hello World'
+ 1 'zip'
+ 2 'tom'
+ 3 'and'
+ 4 'welcome'
+ 5 undef
+ 6 'jerry'
+ 7 'welcome'
+ 8 'this'
+ 9 'that'
+
+That's not much help, a couple of welcomes in there, but no indication of
+which are keys, and which are values, it's just a listed array dump and, in
+this case, not particularly helpful. The trick here, is to use a B<reference>
+to the data structure:
+
+ DB<13> x \%data
+ 0 HASH(0x8194bc4)
+ 'Hello World' => 'zip'
+ 'jerry' => 'welcome'
+ 'this' => 'that'
+ 'tom' => 'and'
+ 'welcome' => undef
+
+The reference is truly dumped and we can finally see what we're dealing with.
+Our quoting was perfectly valid but wrong for our purposes, with 'and jerry'
+being treated as 2 separate words rather than a phrase, thus throwing the
+evenly paired hash structure out of alignment.
+
+The 'B<-w>' switch would have told us about this, had we used it at the start,
+and saved us a lot of trouble:
+
+ > perl -w data
+ Odd number of elements in hash assignment at ./data line 5.
+
+We fix our quoting: 'tom' => q(and jerry), and run it again, this time we get
+our expected output:
+
+ > perl -w data
+ Hello World
+
+
+While we're here, take a closer look at the 'B<x>' command, it's really useful
+and will merrily dump out nested references, complete objects, partial objects
+- just about whatever you throw at it:
+
+Let's make a quick object and x-plode it, first we'll start the debugger:
+it wants some form of input from STDIN, so we give it something non-committal,
+a zero:
+
+ > perl -de 0
+ Default die handler restored.
+
+ Loading DB routines from perl5db.pl version 1.07
+ Editor support available.
+
+ Enter h or `h h' for help, or `man perldebug' for more help.
+
+ main::(-e:1): 0
+
+Now build an on-the-fly object over a couple of lines (note the backslash):
+
+ DB<1> $obj = bless({'unique_id'=>'123', 'attr'=> \
+ cont: {'col' => 'black', 'things' => [qw(this that etc)]}}, 'MY_class')
+
+And let's have a look at it:
+
+ DB<2> x $obj
+ 0 MY_class=HASH(0x828ad98)
+ 'attr' => HASH(0x828ad68)
+ 'col' => 'black'
+ 'things' => ARRAY(0x828abb8)
+ 0 'this'
+ 1 'that'
+ 2 'etc'
+ 'unique_id' => 123
+ DB<3>
+
+Useful, huh? You can eval nearly anything in there, and experiment with bits
+of code or regexes until the cows come home:
+
+ DB<3> @data = qw(this that the other atheism leather theory scythe)
+
+ DB<4> p 'saw -> '.($cnt += map { print "\t:\t$_\n" } grep(/the/, sort @data))
+ atheism
+ leather
+ other
+ scythe
+ the
+ theory
+ saw -> 6
+
+If you want to see the command History, type an 'B<H>':
+
+ DB<5> H
+ 4: p 'saw -> '.($cnt += map { print "\t:\t$_\n" } grep(/the/, sort @data))
+ 3: @data = qw(this that the other atheism leather theory scythe)
+ 2: x $obj
+ 1: $obj = bless({'unique_id'=>'123', 'attr'=>
+ {'col' => 'black', 'things' => [qw(this that etc)]}}, 'MY_class')
+ DB<5>
+
+And if you want to repeat any previous command, use the exclamation: 'B<!>':
+
+ DB<5> !4
+ p 'saw -> '.($cnt += map { print "$_\n" } grep(/the/, sort @data))
+ atheism
+ leather
+ other
+ scythe
+ the
+ theory
+ saw -> 12
+
+For more on references see L<perlref> and L<perlreftut>
+
+
+=head1 Stepping through code
+
+Here's a simple program which converts between Celsius and Fahrenheit, it too
+has a problem:
+
+ #!/usr/bin/perl -w
+ use strict;
+
+ my $arg = $ARGV[0] || '-c20';
+
+ if ($arg =~ /^\-(c|f)((\-|\+)*\d+(\.\d+)*)$/) {
+ my ($deg, $num) = ($1, $2);
+ my ($in, $out) = ($num, $num);
+ if ($deg eq 'c') {
+ $deg = 'f';
+ $out = &c2f($num);
+ } else {
+ $deg = 'c';
+ $out = &f2c($num);
+ }
+ $out = sprintf('%0.2f', $out);
+ $out =~ s/^((\-|\+)*\d+)\.0+$/$1/;
+ print "$out $deg\n";
+ } else {
+ print "Usage: $0 -[c|f] num\n";
+ }
+ exit;
+
+ sub f2c {
+ my $f = shift;
+ my $c = 5 * $f - 32 / 9;
+ return $c;
+ }
+
+ sub c2f {
+ my $c = shift;
+ my $f = 9 * $c / 5 + 32;
+ return $f;
+ }
+
+
+For some reason, the Fahrenheit to Celsius conversion fails to return the
+expected output. This is what it does:
+
+ > temp -c0.72
+ 33.30 f
+
+ > temp -f33.3
+ 162.94 c
+
+Not very consistent! We'll set a breakpoint in the code manually and run it
+under the debugger to see what's going on. A breakpoint is a flag, to which
+the debugger will run without interruption, when it reaches the breakpoint, it
+will stop execution and offer a prompt for further interaction. In normal
+use, these debugger commands are completely ignored, and they are safe - if a
+little messy, to leave in production code.
+
+ my ($in, $out) = ($num, $num);
+ $DB::single=2; # insert at line 9!
+ if ($deg eq 'c')
+ ...
+
+ > perl -d temp -f33.3
+ Default die handler restored.
+
+ Loading DB routines from perl5db.pl version 1.07
+ Editor support available.
+
+ Enter h or `h h' for help, or `man perldebug' for more help.
+
+ main::(temp:4): my $arg = $ARGV[0] || '-c100';
+
+We'll simply continue down to our pre-set breakpoint with a 'B<c>':
+
+ DB<1> c
+ main::(temp:10): if ($deg eq 'c') {
+
+Followed by a view command to see where we are:
+
+ DB<1> v
+ 7: my ($deg, $num) = ($1, $2);
+ 8: my ($in, $out) = ($num, $num);
+ 9: $DB::single=2;
+ 10==> if ($deg eq 'c') {
+ 11: $deg = 'f';
+ 12: $out = &c2f($num);
+ 13 } else {
+ 14: $deg = 'c';
+ 15: $out = &f2c($num);
+ 16 }
+
+And a print to show what values we're currently using:
+
+ DB<1> p $deg, $num
+ f33.3
+
+We can put another break point on any line beginning with a colon, we'll use
+line 17 as that's just as we come out of the subroutine, and we'd like to
+pause there later on:
+
+ DB<2> b 17
+
+There's no feedback from this, but you can see what breakpoints are set by
+using the list 'L' command:
+
+ DB<3> L
+ temp:
+ 17: print "$out $deg\n";
+ break if (1)
+
+Note that to delete a breakpoint you use 'd' or 'D'.
+
+Now we'll continue down into our subroutine, this time rather than by line
+number, we'll use the subroutine name, followed by the now familiar 'v':
+
+ DB<3> c f2c
+ main::f2c(temp:30): my $f = shift;
+
+ DB<4> v
+ 24: exit;
+ 25
+ 26 sub f2c {
+ 27==> my $f = shift;
+ 28: my $c = 5 * $f - 32 / 9;
+ 29: return $c;
+ 30 }
+ 31
+ 32 sub c2f {
+ 33: my $c = shift;
+
+
+Note that if there was a subroutine call between us and line 29, and we wanted
+to B<single-step> through it, we could use the 'B<s>' command, and to step
+over it we would use 'B<n>' which would execute the sub, but not descend into
+it for inspection. In this case though, we simply continue down to line 29:
+
+ DB<4> c 29
+ main::f2c(temp:29): return $c;
+
+And have a look at the return value:
+
+ DB<5> p $c
+ 162.944444444444
+
+This is not the right answer at all, but the sum looks correct. I wonder if
+it's anything to do with operator precedence? We'll try a couple of other
+possibilities with our sum:
+
+ DB<6> p (5 * $f - 32 / 9)
+ 162.944444444444
+
+ DB<7> p 5 * $f - (32 / 9)
+ 162.944444444444
+
+ DB<8> p (5 * $f) - 32 / 9
+ 162.944444444444
+
+ DB<9> p 5 * ($f - 32) / 9
+ 0.722222222222221
+
+:-) that's more like it! Ok, now we can set our return variable and we'll
+return out of the sub with an 'r':
+
+ DB<10> $c = 5 * ($f - 32) / 9
+
+ DB<11> r
+ scalar context return from main::f2c: 0.722222222222221
+
+Looks good, let's just continue off the end of the script:
+
+ DB<12> c
+ 0.72 c
+ Debugged program terminated. Use q to quit or R to restart,
+ use O inhibit_exit to avoid stopping after program termination,
+ h q, h R or h O to get additional info.
+
+A quick fix to the offending line (insert the missing parentheses) in the
+actual program and we're finished.
+
+
+=head1 Placeholder for a, w, t, T
+
+Actions, watch variables, stack traces etc.: on the TODO list.
+
+ a
+
+ w
+
+ t
+
+ T
+
+
+=head1 REGULAR EXPRESSIONS
+
+Ever wanted to know what a regex looked like? You'll need perl compiled with
+the DEBUGGING flag for this one:
+
+ > perl -Dr -e '/^pe(a)*rl$/i'
+ Compiling REx `^pe(a)*rl$'
+ size 17 first at 2
+ rarest char
+ at 0
+ 1: BOL(2)
+ 2: EXACTF <pe>(4)
+ 4: CURLYN[1] {0,32767}(14)
+ 6: NOTHING(8)
+ 8: EXACTF <a>(0)
+ 12: WHILEM(0)
+ 13: NOTHING(14)
+ 14: EXACTF <rl>(16)
+ 16: EOL(17)
+ 17: END(0)
+ floating `'$ at 4..2147483647 (checking floating) stclass `EXACTF <pe>'
+anchored(BOL) minlen 4
+ Omitting $` $& $' support.
+
+ EXECUTING...
+
+ Freeing REx: `^pe(a)*rl$'
+
+Did you really want to know? :-)
+For more gory details on getting regular expressions to work, have a look at
+L<perlre>, L<perlretut>, and to decode the mysterious labels (BOL and CURLYN,
+etc. above), see L<perldebguts>.
+
+
+=head1 OUTPUT TIPS
+
+To get all the output from your error log, and not miss any messages via
+helpful operating system buffering, insert a line like this, at the start of
+your script:
+
+ $|=1;
+
+To watch the tail of a dynamically growing logfile, (from the command line):
+
+ tail -f $error_log
+
+Wrapping all die calls in a handler routine can be useful to see how, and from
+where, they're being called, L<perlvar> has more information:
+
+ BEGIN { $SIG{__DIE__} = sub { require Carp; Carp::confess(@_) } }
+
+Various useful techniques for the redirection of STDOUT and STDERR filehandles
+are explained in L<perlopentut> and L<perlfaq8>.
+
+
+=head1 CGI
+
+Just a quick hint here for all those CGI programmers who can't figure out how
+on earth to get past that 'waiting for input' prompt, when running their CGI
+script from the command-line, try something like this:
+
+ > perl -d my_cgi.pl -nodebug
+
+Of course L<CGI> and L<perlfaq9> will tell you more.
+
+
+=head1 GUIs
+
+The command line interface is tightly integrated with an B<emacs> extension
+and there's a B<vi> interface too.
+
+You don't have to do this all on the command line, though, there are a few GUI
+options out there. The nice thing about these is you can wave a mouse over a
+variable and a dump of its data will appear in an appropriate window, or in a
+popup balloon, no more tiresome typing of 'x $varname' :-)
+
+In particular have a hunt around for the following:
+
+B<ptkdb> perlTK based wrapper for the built-in debugger
+
+B<ddd> data display debugger
+
+B<PerlDevKit> and B<PerlBuilder> are NT specific
+
+NB. (more info on these and others would be appreciated).
+
+
+=head1 SUMMARY
+
+We've seen how to encourage good coding practices with B<use strict> and
+B<-w>. We can run the perl debugger B<perl -d scriptname> to inspect your
+data from within the perl debugger with the B<p> and B<x> commands. You can
+walk through your code, set breakpoints with B<b> and step through that code
+with B<s> or B<n>, continue with B<c> and return from a sub with B<r>. Fairly
+intuitive stuff when you get down to it.
+
+There is of course lots more to find out about, this has just scratched the
+surface. The best way to learn more is to use perldoc to find out more about
+the language, to read the on-line help (L<perldebug> is probably the next
+place to go), and of course, experiment.
+
+
+=head1 SEE ALSO
+
+L<perldebug>,
+L<perldebguts>,
+L<perldiag>,
+L<dprofpp>,
+L<perlrun>
+
+
+=head1 AUTHOR
+
+Richard Foley <richard.foley@rfi.net> Copyright (c) 2000
+
+
+=head1 CONTRIBUTORS
+
+Various people have made helpful suggestions and contributions, in particular:
+
+Ronald J Kimball <rjk@linguist.dartmouth.edu>
+
+Hugo van der Sanden <hv@crypt0.demon.co.uk>
+
+Peter Scott <Peter@PSDT.com>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perldebug.pod b/Master/tlpkg/tlperl/lib/pods/perldebug.pod
new file mode 100644
index 00000000000..9e67b4df422
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldebug.pod
@@ -0,0 +1,1175 @@
+=head1 NAME
+X<debug> X<debugger>
+
+perldebug - Perl debugging
+
+=head1 DESCRIPTION
+
+First of all, have you tried using the B<-w> switch?
+
+
+If you're new to the Perl debugger, you may prefer to read
+L<perldebtut>, which is a tutorial introduction to the debugger .
+
+=head1 The Perl Debugger
+
+If you invoke Perl with the B<-d> switch, your script runs under the
+Perl source debugger. This works like an interactive Perl
+environment, prompting for debugger commands that let you examine
+source code, set breakpoints, get stack backtraces, change the values of
+variables, etc. This is so convenient that you often fire up
+the debugger all by itself just to test out Perl constructs
+interactively to see what they do. For example:
+X<-d>
+
+ $ perl -d -e 42
+
+In Perl, the debugger is not a separate program the way it usually is in the
+typical compiled environment. Instead, the B<-d> flag tells the compiler
+to insert source information into the parse trees it's about to hand off
+to the interpreter. That means your code must first compile correctly
+for the debugger to work on it. Then when the interpreter starts up, it
+preloads a special Perl library file containing the debugger.
+
+The program will halt I<right before> the first run-time executable
+statement (but see below regarding compile-time statements) and ask you
+to enter a debugger command. Contrary to popular expectations, whenever
+the debugger halts and shows you a line of code, it always displays the
+line it's I<about> to execute, rather than the one it has just executed.
+
+Any command not recognized by the debugger is directly executed
+(C<eval>'d) as Perl code in the current package. (The debugger
+uses the DB package for keeping its own state information.)
+
+Note that the said C<eval> is bound by an implicit scope. As a
+result any newly introduced lexical variable or any modified
+capture buffer content is lost after the eval. The debugger is a
+nice environment to learn Perl, but if you interactively experiment using
+material which should be in the same scope, stuff it in one line.
+
+For any text entered at the debugger prompt, leading and trailing whitespace
+is first stripped before further processing. If a debugger command
+coincides with some function in your own program, merely precede the
+function with something that doesn't look like a debugger command, such
+as a leading C<;> or perhaps a C<+>, or by wrapping it with parentheses
+or braces.
+
+=head2 Calling the debugger
+
+There are several ways to call the debugger:
+
+=over 4
+
+=item perl -d program_name
+
+On the given program identified by C<program_name>.
+
+=item perl -d -e 0
+
+Interactively supply an arbitrary C<expression> using C<-e>.
+
+=item perl -d:Ptkdb program_name
+
+Debug a given program via the C<Devel::Ptkdb> GUI.
+
+=item perl -dt threaded_program_name
+
+Debug a given program using threads (experimental).
+
+=back
+
+=head2 Debugger Commands
+
+The interactive debugger understands the following commands:
+
+=over 12
+
+=item h
+X<debugger command, h>
+
+Prints out a summary help message
+
+=item h [command]
+
+Prints out a help message for the given debugger command.
+
+=item h h
+
+The special argument of C<h h> produces the entire help page, which is quite long.
+
+If the output of the C<h h> command (or any command, for that matter) scrolls
+past your screen, precede the command with a leading pipe symbol so
+that it's run through your pager, as in
+
+ DB> |h h
+
+You may change the pager which is used via C<o pager=...> command.
+
+
+=item p expr
+X<debugger command, p>
+
+Same as C<print {$DB::OUT} expr> in the current package. In particular,
+because this is just Perl's own C<print> function, this means that nested
+data structures and objects are not dumped, unlike with the C<x> command.
+
+The C<DB::OUT> filehandle is opened to F</dev/tty>, regardless of
+where STDOUT may be redirected to.
+
+=item x [maxdepth] expr
+X<debugger command, x>
+
+Evaluates its expression in list context and dumps out the result in a
+pretty-printed fashion. Nested data structures are printed out
+recursively, unlike the real C<print> function in Perl. When dumping
+hashes, you'll probably prefer 'x \%h' rather than 'x %h'.
+See L<Dumpvalue> if you'd like to do this yourself.
+
+The output format is governed by multiple options described under
+L<"Configurable Options">.
+
+If the C<maxdepth> is included, it must be a numeral I<N>; the value is
+dumped only I<N> levels deep, as if the C<dumpDepth> option had been
+temporarily set to I<N>.
+
+=item V [pkg [vars]]
+X<debugger command, V>
+
+Display all (or some) variables in package (defaulting to C<main>)
+using a data pretty-printer (hashes show their keys and values so
+you see what's what, control characters are made printable, etc.).
+Make sure you don't put the type specifier (like C<$>) there, just
+the symbol names, like this:
+
+ V DB filename line
+
+Use C<~pattern> and C<!pattern> for positive and negative regexes.
+
+This is similar to calling the C<x> command on each applicable var.
+
+=item X [vars]
+X<debugger command, X>
+
+Same as C<V currentpackage [vars]>.
+
+=item y [level [vars]]
+X<debugger command, y>
+
+Display all (or some) lexical variables (mnemonic: C<mY> variables)
+in the current scope or I<level> scopes higher. You can limit the
+variables that you see with I<vars> which works exactly as it does
+for the C<V> and C<X> commands. Requires the C<PadWalker> module
+version 0.08 or higher; will warn if this isn't installed. Output
+is pretty-printed in the same style as for C<V> and the format is
+controlled by the same options.
+
+=item T
+X<debugger command, T> X<backtrace> X<stack, backtrace>
+
+Produce a stack backtrace. See below for details on its output.
+
+=item s [expr]
+X<debugger command, s> X<step>
+
+Single step. Executes until the beginning of another
+statement, descending into subroutine calls. If an expression is
+supplied that includes function calls, it too will be single-stepped.
+
+=item n [expr]
+X<debugger command, n>
+
+Next. Executes over subroutine calls, until the beginning
+of the next statement. If an expression is supplied that includes
+function calls, those functions will be executed with stops before
+each statement.
+
+=item r
+X<debugger command, r>
+
+Continue until the return from the current subroutine.
+Dump the return value if the C<PrintRet> option is set (default).
+
+=item <CR>
+
+Repeat last C<n> or C<s> command.
+
+=item c [line|sub]
+X<debugger command, c>
+
+Continue, optionally inserting a one-time-only breakpoint
+at the specified line or subroutine.
+
+=item l
+X<debugger command, l>
+
+List next window of lines.
+
+=item l min+incr
+
+List C<incr+1> lines starting at C<min>.
+
+=item l min-max
+
+List lines C<min> through C<max>. C<l -> is synonymous to C<->.
+
+=item l line
+
+List a single line.
+
+=item l subname
+
+List first window of lines from subroutine. I<subname> may
+be a variable that contains a code reference.
+
+=item -
+X<debugger command, ->
+
+List previous window of lines.
+
+=item v [line]
+X<debugger command, v>
+
+View a few lines of code around the current line.
+
+=item .
+X<debugger command, .>
+
+Return the internal debugger pointer to the line last
+executed, and print out that line.
+
+=item f filename
+X<debugger command, f>
+
+Switch to viewing a different file or C<eval> statement. If I<filename>
+is not a full pathname found in the values of %INC, it is considered
+a regex.
+
+C<eval>ed strings (when accessible) are considered to be filenames:
+C<f (eval 7)> and C<f eval 7\b> access the body of the 7th C<eval>ed string
+(in the order of execution). The bodies of the currently executed C<eval>
+and of C<eval>ed strings that define subroutines are saved and thus
+accessible.
+
+=item /pattern/
+
+Search forwards for pattern (a Perl regex); final / is optional.
+The search is case-insensitive by default.
+
+=item ?pattern?
+
+Search backwards for pattern; final ? is optional.
+The search is case-insensitive by default.
+
+=item L [abw]
+X<debugger command, L>
+
+List (default all) actions, breakpoints and watch expressions
+
+=item S [[!]regex]
+X<debugger command, S>
+
+List subroutine names [not] matching the regex.
+
+=item t
+X<debugger command, t>
+
+Toggle trace mode (see also the C<AutoTrace> option).
+
+=item t expr
+X<debugger command, t>
+
+Trace through execution of C<expr>.
+See L<perldebguts/"Frame Listing Output Examples"> for examples.
+
+=item b
+X<breakpoint>
+X<debugger command, b>
+
+Sets breakpoint on current line
+
+=item b [line] [condition]
+X<breakpoint>
+X<debugger command, b>
+
+Set a breakpoint before the given line. If a condition
+is specified, it's evaluated each time the statement is reached: a
+breakpoint is taken only if the condition is true. Breakpoints may
+only be set on lines that begin an executable statement. Conditions
+don't use C<if>:
+
+ b 237 $x > 30
+ b 237 ++$count237 < 11
+ b 33 /pattern/i
+
+=item b subname [condition]
+X<breakpoint>
+X<debugger command, b>
+
+Set a breakpoint before the first line of the named subroutine. I<subname> may
+be a variable containing a code reference (in this case I<condition>
+is not supported).
+
+=item b postpone subname [condition]
+X<breakpoint>
+X<debugger command, b>
+
+Set a breakpoint at first line of subroutine after it is compiled.
+
+=item b load filename
+X<breakpoint>
+X<debugger command, b>
+
+Set a breakpoint before the first executed line of the I<filename>,
+which should be a full pathname found amongst the %INC values.
+
+=item b compile subname
+X<breakpoint>
+X<debugger command, b>
+
+Sets a breakpoint before the first statement executed after the specified
+subroutine is compiled.
+
+=item B line
+X<breakpoint>
+X<debugger command, B>
+
+Delete a breakpoint from the specified I<line>.
+
+=item B *
+X<breakpoint>
+X<debugger command, B>
+
+Delete all installed breakpoints.
+
+=item a [line] command
+X<debugger command, a>
+
+Set an action to be done before the line is executed. If I<line> is
+omitted, set an action on the line about to be executed.
+The sequence of steps taken by the debugger is
+
+ 1. check for a breakpoint at this line
+ 2. print the line if necessary (tracing)
+ 3. do any actions associated with that line
+ 4. prompt user if at a breakpoint or in single-step
+ 5. evaluate line
+
+For example, this will print out $foo every time line
+53 is passed:
+
+ a 53 print "DB FOUND $foo\n"
+
+=item A line
+X<debugger command, A>
+
+Delete an action from the specified line.
+
+=item A *
+X<debugger command, A>
+
+Delete all installed actions.
+
+=item w expr
+X<debugger command, w>
+
+Add a global watch-expression. Whenever a watched global changes the
+debugger will stop and display the old and new values.
+
+=item W expr
+X<debugger command, W>
+
+Delete watch-expression
+
+=item W *
+X<debugger command, W>
+
+Delete all watch-expressions.
+
+=item o
+X<debugger command, o>
+
+Display all options
+
+=item o booloption ...
+X<debugger command, o>
+
+Set each listed Boolean option to the value C<1>.
+
+=item o anyoption? ...
+X<debugger command, o>
+
+Print out the value of one or more options.
+
+=item o option=value ...
+X<debugger command, o>
+
+Set the value of one or more options. If the value has internal
+whitespace, it should be quoted. For example, you could set C<o
+pager="less -MQeicsNfr"> to call B<less> with those specific options.
+You may use either single or double quotes, but if you do, you must
+escape any embedded instances of same sort of quote you began with,
+as well as any escaping any escapes that immediately precede that
+quote but which are not meant to escape the quote itself. In other
+words, you follow single-quoting rules irrespective of the quote;
+eg: C<o option='this isn\'t bad'> or C<o option="She said, \"Isn't
+it?\"">.
+
+For historical reasons, the C<=value> is optional, but defaults to
+1 only where it is safe to do so--that is, mostly for Boolean
+options. It is always better to assign a specific value using C<=>.
+The C<option> can be abbreviated, but for clarity probably should
+not be. Several options can be set together. See L<"Configurable Options">
+for a list of these.
+
+=item < ?
+X<< debugger command, < >>
+
+List out all pre-prompt Perl command actions.
+
+=item < [ command ]
+X<< debugger command, < >>
+
+Set an action (Perl command) to happen before every debugger prompt.
+A multi-line command may be entered by backslashing the newlines.
+
+=item < *
+X<< debugger command, < >>
+
+Delete all pre-prompt Perl command actions.
+
+=item << command
+X<< debugger command, << >>
+
+Add an action (Perl command) to happen before every debugger prompt.
+A multi-line command may be entered by backwhacking the newlines.
+
+=item > ?
+X<< debugger command, > >>
+
+List out post-prompt Perl command actions.
+
+=item > command
+X<< debugger command, > >>
+
+Set an action (Perl command) to happen after the prompt when you've
+just given a command to return to executing the script. A multi-line
+command may be entered by backslashing the newlines (we bet you
+couldn't have guessed this by now).
+
+=item > *
+X<< debugger command, > >>
+
+Delete all post-prompt Perl command actions.
+
+=item >> command
+X<<< debugger command, >> >>>
+
+Adds an action (Perl command) to happen after the prompt when you've
+just given a command to return to executing the script. A multi-line
+command may be entered by backslashing the newlines.
+
+=item { ?
+X<debugger command, {>
+
+List out pre-prompt debugger commands.
+
+=item { [ command ]
+
+Set an action (debugger command) to happen before every debugger prompt.
+A multi-line command may be entered in the customary fashion.
+
+Because this command is in some senses new, a warning is issued if
+you appear to have accidentally entered a block instead. If that's
+what you mean to do, write it as with C<;{ ... }> or even
+C<do { ... }>.
+
+=item { *
+X<debugger command, {>
+
+Delete all pre-prompt debugger commands.
+
+=item {{ command
+X<debugger command, {{>
+
+Add an action (debugger command) to happen before every debugger prompt.
+A multi-line command may be entered, if you can guess how: see above.
+
+=item ! number
+X<debugger command, !>
+
+Redo a previous command (defaults to the previous command).
+
+=item ! -number
+X<debugger command, !>
+
+Redo number'th previous command.
+
+=item ! pattern
+X<debugger command, !>
+
+Redo last command that started with pattern.
+See C<o recallCommand>, too.
+
+=item !! cmd
+X<debugger command, !!>
+
+Run cmd in a subprocess (reads from DB::IN, writes to DB::OUT) See
+C<o shellBang>, also. Note that the user's current shell (well,
+their C<$ENV{SHELL}> variable) will be used, which can interfere
+with proper interpretation of exit status or signal and coredump
+information.
+
+=item source file
+X<debugger command, source>
+
+Read and execute debugger commands from I<file>.
+I<file> may itself contain C<source> commands.
+
+=item H -number
+X<debugger command, H>
+
+Display last n commands. Only commands longer than one character are
+listed. If I<number> is omitted, list them all.
+
+=item q or ^D
+X<debugger command, q>
+X<debugger command, ^D>
+
+Quit. ("quit" doesn't work for this, unless you've made an alias)
+This is the only supported way to exit the debugger, though typing
+C<exit> twice might work.
+
+Set the C<inhibit_exit> option to 0 if you want to be able to step
+off the end the script. You may also need to set $finished to 0
+if you want to step through global destruction.
+
+=item R
+X<debugger command, R>
+
+Restart the debugger by C<exec()>ing a new session. We try to maintain
+your history across this, but internal settings and command-line options
+may be lost.
+
+The following setting are currently preserved: history, breakpoints,
+actions, debugger options, and the Perl command-line
+options B<-w>, B<-I>, and B<-e>.
+
+=item |dbcmd
+X<debugger command, |>
+
+Run the debugger command, piping DB::OUT into your current pager.
+
+=item ||dbcmd
+X<debugger command, ||>
+
+Same as C<|dbcmd> but DB::OUT is temporarily C<select>ed as well.
+
+=item = [alias value]
+X<debugger command, =>
+
+Define a command alias, like
+
+ = quit q
+
+or list current aliases.
+
+=item command
+
+Execute command as a Perl statement. A trailing semicolon will be
+supplied. If the Perl statement would otherwise be confused for a
+Perl debugger, use a leading semicolon, too.
+
+=item m expr
+X<debugger command, m>
+
+List which methods may be called on the result of the evaluated
+expression. The expression may evaluated to a reference to a
+blessed object, or to a package name.
+
+=item M
+X<debugger command, M>
+
+Displays all loaded modules and their versions
+
+
+=item man [manpage]
+X<debugger command, man>
+
+Despite its name, this calls your system's default documentation
+viewer on the given page, or on the viewer itself if I<manpage> is
+omitted. If that viewer is B<man>, the current C<Config> information
+is used to invoke B<man> using the proper MANPATH or S<B<-M>
+I<manpath>> option. Failed lookups of the form C<XXX> that match
+known manpages of the form I<perlXXX> will be retried. This lets
+you type C<man debug> or C<man op> from the debugger.
+
+On systems traditionally bereft of a usable B<man> command, the
+debugger invokes B<perldoc>. Occasionally this determination is
+incorrect due to recalcitrant vendors or rather more felicitously,
+to enterprising users. If you fall into either category, just
+manually set the $DB::doccmd variable to whatever viewer to view
+the Perl documentation on your system. This may be set in an rc
+file, or through direct assignment. We're still waiting for a
+working example of something along the lines of:
+
+ $DB::doccmd = 'netscape -remote http://something.here/';
+
+=back
+
+=head2 Configurable Options
+
+The debugger has numerous options settable using the C<o> command,
+either interactively or from the environment or an rc file.
+(./.perldb or ~/.perldb under Unix.)
+
+
+=over 12
+
+=item C<recallCommand>, C<ShellBang>
+X<debugger option, recallCommand>
+X<debugger option, ShellBang>
+
+The characters used to recall command or spawn shell. By
+default, both are set to C<!>, which is unfortunate.
+
+=item C<pager>
+X<debugger option, pager>
+
+Program to use for output of pager-piped commands (those beginning
+with a C<|> character.) By default, C<$ENV{PAGER}> will be used.
+Because the debugger uses your current terminal characteristics
+for bold and underlining, if the chosen pager does not pass escape
+sequences through unchanged, the output of some debugger commands
+will not be readable when sent through the pager.
+
+=item C<tkRunning>
+X<debugger option, tkRunning>
+
+Run Tk while prompting (with ReadLine).
+
+=item C<signalLevel>, C<warnLevel>, C<dieLevel>
+X<debugger option, signalLevel> X<debugger option, warnLevel>
+X<debugger option, dieLevel>
+
+Level of verbosity. By default, the debugger leaves your exceptions
+and warnings alone, because altering them can break correctly running
+programs. It will attempt to print a message when uncaught INT, BUS, or
+SEGV signals arrive. (But see the mention of signals in L<BUGS> below.)
+
+To disable this default safe mode, set these values to something higher
+than 0. At a level of 1, you get backtraces upon receiving any kind
+of warning (this is often annoying) or exception (this is
+often valuable). Unfortunately, the debugger cannot discern fatal
+exceptions from non-fatal ones. If C<dieLevel> is even 1, then your
+non-fatal exceptions are also traced and unceremoniously altered if they
+came from C<eval'ed> strings or from any kind of C<eval> within modules
+you're attempting to load. If C<dieLevel> is 2, the debugger doesn't
+care where they came from: It usurps your exception handler and prints
+out a trace, then modifies all exceptions with its own embellishments.
+This may perhaps be useful for some tracing purposes, but tends to hopelessly
+destroy any program that takes its exception handling seriously.
+
+=item C<AutoTrace>
+X<debugger option, AutoTrace>
+
+Trace mode (similar to C<t> command, but can be put into
+C<PERLDB_OPTS>).
+
+=item C<LineInfo>
+X<debugger option, LineInfo>
+
+File or pipe to print line number info to. If it is a pipe (say,
+C<|visual_perl_db>), then a short message is used. This is the
+mechanism used to interact with a slave editor or visual debugger,
+such as the special C<vi> or C<emacs> hooks, or the C<ddd> graphical
+debugger.
+
+=item C<inhibit_exit>
+X<debugger option, inhibit_exit>
+
+If 0, allows I<stepping off> the end of the script.
+
+=item C<PrintRet>
+X<debugger option, PrintRet>
+
+Print return value after C<r> command if set (default).
+
+=item C<ornaments>
+X<debugger option, ornaments>
+
+Affects screen appearance of the command line (see L<Term::ReadLine>).
+There is currently no way to disable these, which can render
+some output illegible on some displays, or with some pagers.
+This is considered a bug.
+
+=item C<frame>
+X<debugger option, frame>
+
+Affects the printing of messages upon entry and exit from subroutines. If
+C<frame & 2> is false, messages are printed on entry only. (Printing
+on exit might be useful if interspersed with other messages.)
+
+If C<frame & 4>, arguments to functions are printed, plus context
+and caller info. If C<frame & 8>, overloaded C<stringify> and
+C<tie>d C<FETCH> is enabled on the printed arguments. If C<frame
+& 16>, the return value from the subroutine is printed.
+
+The length at which the argument list is truncated is governed by the
+next option:
+
+=item C<maxTraceLen>
+X<debugger option, maxTraceLen>
+
+Length to truncate the argument list when the C<frame> option's
+bit 4 is set.
+
+=item C<windowSize>
+X<debugger option, windowSize>
+
+Change the size of code list window (default is 10 lines).
+
+=back
+
+The following options affect what happens with C<V>, C<X>, and C<x>
+commands:
+
+=over 12
+
+=item C<arrayDepth>, C<hashDepth>
+X<debugger option, arrayDepth> X<debugger option, hashDepth>
+
+Print only first N elements ('' for all).
+
+=item C<dumpDepth>
+X<debugger option, dumpDepth>
+
+Limit recursion depth to N levels when dumping structures.
+Negative values are interpreted as infinity. Default: infinity.
+
+=item C<compactDump>, C<veryCompact>
+X<debugger option, compactDump> X<debugger option, veryCompact>
+
+Change the style of array and hash output. If C<compactDump>, short array
+may be printed on one line.
+
+=item C<globPrint>
+X<debugger option, globPrint>
+
+Whether to print contents of globs.
+
+=item C<DumpDBFiles>
+X<debugger option, DumpDBFiles>
+
+Dump arrays holding debugged files.
+
+=item C<DumpPackages>
+X<debugger option, DumpPackages>
+
+Dump symbol tables of packages.
+
+=item C<DumpReused>
+X<debugger option, DumpReused>
+
+Dump contents of "reused" addresses.
+
+=item C<quote>, C<HighBit>, C<undefPrint>
+X<debugger option, quote> X<debugger option, HighBit>
+X<debugger option, undefPrint>
+
+Change the style of string dump. The default value for C<quote>
+is C<auto>; one can enable double-quotish or single-quotish format
+by setting it to C<"> or C<'>, respectively. By default, characters
+with their high bit set are printed verbatim.
+
+=item C<UsageOnly>
+X<debugger option, UsageOnly>
+
+Rudimentary per-package memory usage dump. Calculates total
+size of strings found in variables in the package. This does not
+include lexicals in a module's file scope, or lost in closures.
+
+=back
+
+After the rc file is read, the debugger reads the C<$ENV{PERLDB_OPTS}>
+environment variable and parses this as the remainder of a "O ..."
+line as one might enter at the debugger prompt. You may place the
+initialization options C<TTY>, C<noTTY>, C<ReadLine>, and C<NonStop>
+there.
+
+If your rc file contains:
+
+ parse_options("NonStop=1 LineInfo=db.out AutoTrace");
+
+then your script will run without human intervention, putting trace
+information into the file I<db.out>. (If you interrupt it, you'd
+better reset C<LineInfo> to F</dev/tty> if you expect to see anything.)
+
+=over 12
+
+=item C<TTY>
+X<debugger option, TTY>
+
+The TTY to use for debugging I/O.
+
+=item C<noTTY>
+X<debugger option, noTTY>
+
+If set, the debugger goes into C<NonStop> mode and will not connect to a TTY. If
+interrupted (or if control goes to the debugger via explicit setting of
+$DB::signal or $DB::single from the Perl script), it connects to a TTY
+specified in the C<TTY> option at startup, or to a tty found at
+runtime using the C<Term::Rendezvous> module of your choice.
+
+This module should implement a method named C<new> that returns an object
+with two methods: C<IN> and C<OUT>. These should return filehandles to use
+for debugging input and output correspondingly. The C<new> method should
+inspect an argument containing the value of C<$ENV{PERLDB_NOTTY}> at
+startup, or C<"$ENV{HOME}/.perldbtty$$"> otherwise. This file is not
+inspected for proper ownership, so security hazards are theoretically
+possible.
+
+=item C<ReadLine>
+X<debugger option, ReadLine>
+
+If false, readline support in the debugger is disabled in order
+to debug applications that themselves use ReadLine.
+
+=item C<NonStop>
+X<debugger option, NonStop>
+
+If set, the debugger goes into non-interactive mode until interrupted, or
+programmatically by setting $DB::signal or $DB::single.
+
+=back
+
+Here's an example of using the C<$ENV{PERLDB_OPTS}> variable:
+
+ $ PERLDB_OPTS="NonStop frame=2" perl -d myprogram
+
+That will run the script B<myprogram> without human intervention,
+printing out the call tree with entry and exit points. Note that
+C<NonStop=1 frame=2> is equivalent to C<N f=2>, and that originally,
+options could be uniquely abbreviated by the first letter (modulo
+the C<Dump*> options). It is nevertheless recommended that you
+always spell them out in full for legibility and future compatibility.
+
+Other examples include
+
+ $ PERLDB_OPTS="NonStop LineInfo=listing frame=2" perl -d myprogram
+
+which runs script non-interactively, printing info on each entry
+into a subroutine and each executed line into the file named F<listing>.
+(If you interrupt it, you would better reset C<LineInfo> to something
+"interactive"!)
+
+Other examples include (using standard shell syntax to show environment
+variable settings):
+
+ $ ( PERLDB_OPTS="NonStop frame=1 AutoTrace LineInfo=tperl.out"
+ perl -d myprogram )
+
+which may be useful for debugging a program that uses C<Term::ReadLine>
+itself. Do not forget to detach your shell from the TTY in the window that
+corresponds to F</dev/ttyXX>, say, by issuing a command like
+
+ $ sleep 1000000
+
+See L<perldebguts/"Debugger Internals"> for details.
+
+=head2 Debugger input/output
+
+=over 8
+
+=item Prompt
+
+The debugger prompt is something like
+
+ DB<8>
+
+or even
+
+ DB<<17>>
+
+where that number is the command number, and which you'd use to
+access with the built-in B<csh>-like history mechanism. For example,
+C<!17> would repeat command number 17. The depth of the angle
+brackets indicates the nesting depth of the debugger. You could
+get more than one set of brackets, for example, if you'd already
+at a breakpoint and then printed the result of a function call that
+itself has a breakpoint, or you step into an expression via C<s/n/t
+expression> command.
+
+=item Multiline commands
+
+If you want to enter a multi-line command, such as a subroutine
+definition with several statements or a format, escape the newline
+that would normally end the debugger command with a backslash.
+Here's an example:
+
+ DB<1> for (1..4) { \
+ cont: print "ok\n"; \
+ cont: }
+ ok
+ ok
+ ok
+ ok
+
+Note that this business of escaping a newline is specific to interactive
+commands typed into the debugger.
+
+=item Stack backtrace
+X<backtrace> X<stack, backtrace>
+
+Here's an example of what a stack backtrace via C<T> command might
+look like:
+
+ $ = main::infested called from file `Ambulation.pm' line 10
+ @ = Ambulation::legs(1, 2, 3, 4) called from file `camel_flea' line 7
+ $ = main::pests('bactrian', 4) called from file `camel_flea' line 4
+
+The left-hand character up there indicates the context in which the
+function was called, with C<$> and C<@> meaning scalar or list
+contexts respectively, and C<.> meaning void context (which is
+actually a sort of scalar context). The display above says
+that you were in the function C<main::infested> when you ran the
+stack dump, and that it was called in scalar context from line
+10 of the file I<Ambulation.pm>, but without any arguments at all,
+meaning it was called as C<&infested>. The next stack frame shows
+that the function C<Ambulation::legs> was called in list context
+from the I<camel_flea> file with four arguments. The last stack
+frame shows that C<main::pests> was called in scalar context,
+also from I<camel_flea>, but from line 4.
+
+If you execute the C<T> command from inside an active C<use>
+statement, the backtrace will contain both a C<require> frame and
+an C<eval>) frame.
+
+=item Line Listing Format
+
+This shows the sorts of output the C<l> command can produce:
+
+ DB<<13>> l
+ 101: @i{@i} = ();
+ 102:b @isa{@i,$pack} = ()
+ 103 if(exists $i{$prevpack} || exists $isa{$pack});
+ 104 }
+ 105
+ 106 next
+ 107==> if(exists $isa{$pack});
+ 108
+ 109:a if ($extra-- > 0) {
+ 110: %isa = ($pack,1);
+
+Breakable lines are marked with C<:>. Lines with breakpoints are
+marked by C<b> and those with actions by C<a>. The line that's
+about to be executed is marked by C<< ==> >>.
+
+Please be aware that code in debugger listings may not look the same
+as your original source code. Line directives and external source
+filters can alter the code before Perl sees it, causing code to move
+from its original positions or take on entirely different forms.
+
+=item Frame listing
+
+When the C<frame> option is set, the debugger would print entered (and
+optionally exited) subroutines in different styles. See L<perldebguts>
+for incredibly long examples of these.
+
+=back
+
+=head2 Debugging compile-time statements
+
+If you have compile-time executable statements (such as code within
+BEGIN, UNITCHECK and CHECK blocks or C<use> statements), these will
+I<not> be stopped by debugger, although C<require>s and INIT blocks
+will, and compile-time statements can be traced with C<AutoTrace>
+option set in C<PERLDB_OPTS>). From your own Perl code, however, you
+can transfer control back to the debugger using the following
+statement, which is harmless if the debugger is not running:
+
+ $DB::single = 1;
+
+If you set C<$DB::single> to 2, it's equivalent to having
+just typed the C<n> command, whereas a value of 1 means the C<s>
+command. The C<$DB::trace> variable should be set to 1 to simulate
+having typed the C<t> command.
+
+Another way to debug compile-time code is to start the debugger, set a
+breakpoint on the I<load> of some module:
+
+ DB<7> b load f:/perllib/lib/Carp.pm
+ Will stop on load of `f:/perllib/lib/Carp.pm'.
+
+and then restart the debugger using the C<R> command (if possible). One can use C<b
+compile subname> for the same purpose.
+
+=head2 Debugger Customization
+
+The debugger probably contains enough configuration hooks that you
+won't ever have to modify it yourself. You may change the behaviour
+of debugger from within the debugger using its C<o> command, from
+the command line via the C<PERLDB_OPTS> environment variable, and
+from customization files.
+
+You can do some customization by setting up a F<.perldb> file, which
+contains initialization code. For instance, you could make aliases
+like these (the last one is one people expect to be there):
+
+ $DB::alias{'len'} = 's/^len(.*)/p length($1)/';
+ $DB::alias{'stop'} = 's/^stop (at|in)/b/';
+ $DB::alias{'ps'} = 's/^ps\b/p scalar /';
+ $DB::alias{'quit'} = 's/^quit(\s*)/exit/';
+
+You can change options from F<.perldb> by using calls like this one;
+
+ parse_options("NonStop=1 LineInfo=db.out AutoTrace=1 frame=2");
+
+The code is executed in the package C<DB>. Note that F<.perldb> is
+processed before processing C<PERLDB_OPTS>. If F<.perldb> defines the
+subroutine C<afterinit>, that function is called after debugger
+initialization ends. F<.perldb> may be contained in the current
+directory, or in the home directory. Because this file is sourced
+in by Perl and may contain arbitrary commands, for security reasons,
+it must be owned by the superuser or the current user, and writable
+by no one but its owner.
+
+You can mock TTY input to debugger by adding arbitrary commands to
+@DB::typeahead. For example, your F<.perldb> file might contain:
+
+ sub afterinit { push @DB::typeahead, "b 4", "b 6"; }
+
+Which would attempt to set breakpoints on lines 4 and 6 immediately
+after debugger initialization. Note that @DB::typeahead is not a supported
+interface and is subject to change in future releases.
+
+If you want to modify the debugger, copy F<perl5db.pl> from the
+Perl library to another name and hack it to your heart's content.
+You'll then want to set your C<PERL5DB> environment variable to say
+something like this:
+
+ BEGIN { require "myperl5db.pl" }
+
+As a last resort, you could also use C<PERL5DB> to customize the debugger
+by directly setting internal variables or calling debugger functions.
+
+Note that any variables and functions that are not documented in
+this document (or in L<perldebguts>) are considered for internal
+use only, and as such are subject to change without notice.
+
+=head2 Readline Support / History in the debugger
+
+As shipped, the only command-line history supplied is a simplistic one
+that checks for leading exclamation points. However, if you install
+the Term::ReadKey and Term::ReadLine modules from CPAN (such as
+Term::ReadLine::Gnu, Term::ReadLine::Perl, ...) you will
+have full editing capabilities much like GNU I<readline>(3) provides.
+Look for these in the F<modules/by-module/Term> directory on CPAN.
+These do not support normal B<vi> command-line editing, however.
+
+A rudimentary command-line completion is also available, including
+lexical variables in the current scope if the C<PadWalker> module
+is installed.
+
+Without Readline support you may see the symbols "^[[A", "^[[C", "^[[B",
+"^[[D"", "^H", ... when using the arrow keys and/or the backspace key.
+
+=head2 Editor Support for Debugging
+
+If you have the FSF's version of B<emacs> installed on your system,
+it can interact with the Perl debugger to provide an integrated
+software development environment reminiscent of its interactions
+with C debuggers.
+
+Perl comes with a start file for making B<emacs> act like a
+syntax-directed editor that understands (some of) Perl's syntax.
+Look in the I<emacs> directory of the Perl source distribution.
+
+A similar setup by Tom Christiansen for interacting with any
+vendor-shipped B<vi> and the X11 window system is also available.
+This works similarly to the integrated multiwindow support that
+B<emacs> provides, where the debugger drives the editor. At the
+time of this writing, however, that tool's eventual location in the
+Perl distribution was uncertain.
+
+Users of B<vi> should also look into B<vim> and B<gvim>, the mousey
+and windy version, for coloring of Perl keywords.
+
+Note that only perl can truly parse Perl, so all such CASE tools
+fall somewhat short of the mark, especially if you don't program
+your Perl as a C programmer might.
+
+=head2 The Perl Profiler
+X<profile> X<profiling> X<profiler>
+
+If you wish to supply an alternative debugger for Perl to run,
+invoke your script with a colon and a package argument given to the
+B<-d> flag. Perl's alternative debuggers include the Perl profiler,
+L<Devel::DProf>, which is included with the standard Perl
+distribution. To profile your Perl program in the file F<mycode.pl>,
+just type:
+
+ $ perl -d:DProf mycode.pl
+
+When the script terminates the profiler will dump the profile
+information to a file called F<tmon.out>. A tool like B<dprofpp>,
+also supplied with the standard Perl distribution, can be used to
+interpret the information in that profile. More powerful profilers,
+such as C<Devel::NYTProf> are available from the CPAN: see L<perlperf>
+for details.
+
+=head1 Debugging regular expressions
+X<regular expression, debugging>
+X<regex, debugging> X<regexp, debugging>
+
+C<use re 'debug'> enables you to see the gory details of how the Perl
+regular expression engine works. In order to understand this typically
+voluminous output, one must not only have some idea about how regular
+expression matching works in general, but also know how Perl's regular
+expressions are internally compiled into an automaton. These matters
+are explored in some detail in
+L<perldebguts/"Debugging regular expressions">.
+
+=head1 Debugging memory usage
+X<memory usage>
+
+Perl contains internal support for reporting its own memory usage,
+but this is a fairly advanced concept that requires some understanding
+of how memory allocation works.
+See L<perldebguts/"Debugging Perl memory usage"> for the details.
+
+=head1 SEE ALSO
+
+You did try the B<-w> switch, didn't you?
+
+L<perldebtut>,
+L<perldebguts>,
+L<re>,
+L<DB>,
+L<Devel::DProf>,
+L<dprofpp>,
+L<Dumpvalue>,
+and
+L<perlrun>.
+
+When debugging a script that uses #! and is thus normally found in
+$PATH, the -S option causes perl to search $PATH for it, so you don't
+have to type the path or C<which $scriptname>.
+
+ $ perl -Sd foo.pl
+
+=head1 BUGS
+
+You cannot get stack frame information or in any fashion debug functions
+that were not compiled by Perl, such as those from C or C++ extensions.
+
+If you alter your @_ arguments in a subroutine (such as with C<shift>
+or C<pop>), the stack backtrace will not show the original values.
+
+The debugger does not currently work in conjunction with the B<-W>
+command-line switch, because it itself is not free of warnings.
+
+If you're in a slow syscall (like C<wait>ing, C<accept>ing, or C<read>ing
+from your keyboard or a socket) and haven't set up your own C<$SIG{INT}>
+handler, then you won't be able to CTRL-C your way back to the debugger,
+because the debugger's own C<$SIG{INT}> handler doesn't understand that
+it needs to raise an exception to longjmp(3) out of slow syscalls.
diff --git a/Master/tlpkg/tlperl/lib/pods/perldelta.pod b/Master/tlpkg/tlperl/lib/pods/perldelta.pod
new file mode 100644
index 00000000000..20d38bb15ca
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldelta.pod
@@ -0,0 +1,116 @@
+=encoding utf8
+
+=head1 NAME
+
+perldelta - what is new for perl v5.12.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.12.2 release and
+the 5.12.3 release.
+
+If you are upgrading from an earlier release such as 5.12.1, first read
+L<perl5122delta>, which describes differences between 5.12.1 and
+5.12.2. The major changes made in 5.12.0 are described in L<perl5120delta>.
+
+=head1 Incompatible Changes
+
+ There are no changes intentionally incompatible with 5.12.2. If any
+ exist, they are bugs and reports are welcome.
+
+=head1 Core Enhancements
+
+=head2 C<keys>, C<values> work on arrays
+
+You can now use the C<keys>, C<values>, C<each> builtin functions on arrays
+(previously you could only use them on hashes). See L<perlfunc> for details.
+This is actually a change introduced in perl 5.12.0, but it was missed from
+that release's perldelta.
+
+=head1 Bug Fixes
+
+"no VERSION" will now correctly deparse with B::Deparse, as will certain
+constant expressions.
+
+Module::Build should be more reliably pass its tests under cygwin.
+
+lvalue sub return values are now COW.
+
+=head1 Platform Specific Notes
+
+=over 4
+
+=item Solaris
+
+A separate DTrace is now build for miniperl, which means that perl can be
+compiled with -Dusedtrace on Solaris again.
+
+=item VMS
+
+A number of regressions on VMS have been fixed. In addition to minor cleanup
+of questionable expressions in F<vms.c>, file permissions should no longer be
+garbled by the PerlIO layer, and spurious record boundaries should no longer be
+introduced by the PerlIO layer during output.
+
+For more details and discussion on the latter, see:
+
+ http://www.nntp.perl.org/group/perl.vmsperl/2010/11/msg15419.html
+
+=item VOS
+
+A few very small changes were made to the build process on VOS to better
+support the platform. Longer-than-32-character filenames are now supported on
+OpenVOS, and build properly without IPv6 support.
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.12.3 represents approximately four months of development since
+Perl 5.12.2 and contains approximately 2500 lines of changes across
+54 files from 16 authors.
+
+Perl continues to flourish into its third decade thanks to a vibrant
+community of users and developers. The following people are known to
+have contributed the improvements that became Perl 5.12.3:
+
+Craig A. Berry, David Golden, David Leadbeater, Father Chrysostomos, Florian
+Ragwitz, Jesse Vincent, Karl Williamson, Nick Johnston, Nicolas Kaiser, Paul
+Green, Rafael Garcia-Suarez, Rainer Tammer, Ricardo Signes, Steffen Mueller,
+Zsbán Ambrus, Ævar Arnfjörð Bjarmason
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://rt.perl.org/perlbug/ . There may also be
+information at http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the B<perlbug>
+program included with your release. Be sure to trim your bug down
+to a tiny but sufficient test case. Your bug report, along with the
+output of C<perl -V>, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send
+it to perl5-security-report@perl.org. This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who be able
+to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported. Please only use this address for
+security issues in the Perl core, not for modules independently
+distributed on CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details
+on what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perldgux.pod b/Master/tlpkg/tlperl/lib/pods/perldgux.pod
new file mode 100644
index 00000000000..8e2cbf15cd3
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldgux.pod
@@ -0,0 +1,117 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perldgux - Perl under DG/UX.
+
+=head1 SYNOPSIS
+
+One can read this document in the following formats:
+
+ man perldgux
+ view perl perldgux
+ explorer perldgux.html
+ info perldgux
+
+to list some (not all may be available simultaneously), or it may
+be read I<as is>: as F<README.dgux>.
+
+=cut
+
+Contents
+
+ perldgux - Perl under DG/UX.
+
+ NAME
+ SYNOPSIS
+ DESCRIPTION
+ BUILD
+ - Non-threaded Case
+ - Threaded Case
+ - Testing
+ - Installing the built perl
+ AUTHOR
+ SEE ALSO
+
+=head1 DESCRIPTION
+
+Perl 5.7/8.x for DG/UX ix86 R4.20MU0x
+
+=head1 BUILDING PERL ON DG/UX
+
+=head2 Non-threaded Perl on DG/UX
+
+Just run ./Configure script from the top directory.
+Then give "make" to compile.
+
+=head2 Threaded Perl on DG/UX
+
+If you are using as compiler GCC-2.95.x rev(DG/UX)
+an easy solution for configuring perl in your DG/UX
+machine is to run the command:
+
+./Configure -Dusethreads -Duseithreads -Dusedevel -des
+
+This will automatically accept all the defaults and
+in particular /usr/local/ as installation directory.
+Note that GCC-2.95.x rev(DG/UX) knows the switch
+-pthread which allows it to link correctly DG/UX's
+-lthread library.
+
+If you want to change the installation directory or
+have a standard DG/UX with C compiler GCC-2.7.2.x
+then you have no choice than to do an interactive
+build by issuing the command:
+
+./Configure -Dusethreads -Duseithreads
+
+In particular with GCC-2.7.2.x accept all the defaults
+and *watch* out for the message:
+
+ Any additional ld flags (NOT including libraries)? [ -pthread]
+
+Instead of -pthread put here -lthread. CGCC-2.7.2.x
+that comes with the DG/UX OS does NOT know the -pthread
+switch. So your build will fail if you choose the defaults.
+After configuration is done correctly give "make" to compile.
+
+=head2 Testing Perl on DG/UX
+
+Issuing a "make test" will run all the tests.
+If the test lib/ftmp-security gives you as a result
+something like
+
+ lib/ftmp-security....File::Temp::_gettemp:
+ Parent directory (/tmp/) is not safe (sticky bit not set
+ when world writable?) at lib/ftmp-security.t line 100
+
+don't panic and just set the sticky bit in your /tmp
+directory by doing the following as root:
+
+cd /
+chmod +t /tmp (=set the sticky bit to /tmp).
+
+Then rerun the tests. This time all must be OK.
+
+=head2 Installing the built perl on DG/UX
+
+Run the command "make install"
+
+=head1 AUTHOR
+
+Takis Psarogiannakopoulos
+Universirty of Cambridge
+Centre for Mathematical Sciences
+Department of Pure Mathematics
+Wilberforce road
+Cambridge CB3 0WB , UK
+email <takis@XFree86.Org>
+
+=head1 SEE ALSO
+
+perl(1).
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perldiag.pod b/Master/tlpkg/tlperl/lib/pods/perldiag.pod
new file mode 100644
index 00000000000..5d0f503ef36
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldiag.pod
@@ -0,0 +1,5267 @@
+=head1 NAME
+
+perldiag - various Perl diagnostics
+
+=head1 DESCRIPTION
+
+These messages are classified as follows (listed in increasing order of
+desperation):
+
+ (W) A warning (optional).
+ (D) A deprecation (enabled by default).
+ (S) A severe warning (enabled by default).
+ (F) A fatal error (trappable).
+ (P) An internal error you should never see (trappable).
+ (X) A very fatal error (nontrappable).
+ (A) An alien error message (not generated by Perl).
+
+The majority of messages from the first three classifications above
+(W, D & S) can be controlled using the C<warnings> pragma.
+
+If a message can be controlled by the C<warnings> pragma, its warning
+category is included with the classification letter in the description
+below.
+
+Optional warnings are enabled by using the C<warnings> pragma or the B<-w>
+and B<-W> switches. Warnings may be captured by setting C<$SIG{__WARN__}>
+to a reference to a routine that will be called on each warning instead
+of printing it. See L<perlvar>.
+
+Severe warnings are always enabled, unless they are explicitly disabled
+with the C<warnings> pragma or the B<-X> switch.
+
+Trappable errors may be trapped using the eval operator. See
+L<perlfunc/eval>. In almost all cases, warnings may be selectively
+disabled or promoted to fatal errors using the C<warnings> pragma.
+See L<warnings>.
+
+The messages are in alphabetical order, without regard to upper or
+lower-case. Some of these messages are generic. Spots that vary are
+denoted with a %s or other printf-style escape. These escapes are
+ignored by the alphabetical order, as are all characters other than
+letters. To look up your message, just ignore anything that is not a
+letter.
+
+=over 4
+
+=item accept() on closed socket %s
+
+(W closed) You tried to do an accept on a closed socket. Did you forget
+to check the return value of your socket() call? See
+L<perlfunc/accept>.
+
+=item Allocation too large: %lx
+
+(X) You can't allocate more than 64K on an MS-DOS machine.
+
+=item '%c' allowed only after types %s
+
+(F) The modifiers '!', '<' and '>' are allowed in pack() or unpack() only
+after certain types. See L<perlfunc/pack>.
+
+=item Ambiguous call resolved as CORE::%s(), qualify as such or use &
+
+(W ambiguous) A subroutine you have declared has the same name as a Perl
+keyword, and you have used the name without qualification for calling
+one or the other. Perl decided to call the builtin because the
+subroutine is not imported.
+
+To force interpretation as a subroutine call, either put an ampersand
+before the subroutine name, or qualify the name with its package.
+Alternatively, you can import the subroutine (or pretend that it's
+imported with the C<use subs> pragma).
+
+To silently interpret it as the Perl operator, use the C<CORE::> prefix
+on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
+to be an object method (see L<perlsub/"Subroutine Attributes"> or
+L<attributes>).
+
+=item Ambiguous range in transliteration operator
+
+(F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
+all. To include a C<-> character in a transliteration, put it either
+first or last. (In the past, C<tr/a-z-0//> was synonymous with
+C<tr/a-y//>, which was probably not what you would have expected.)
+
+=item Ambiguous use of %s resolved as %s
+
+(W ambiguous)(S) You said something that may not be interpreted the way
+you thought. Normally it's pretty easy to disambiguate it by supplying
+a missing quote, operator, parenthesis pair or declaration.
+
+=item '|' and '<' may not both be specified on command line
+
+(F) An error peculiar to VMS. Perl does its own command line
+redirection, and found that STDIN was a pipe, and that you also tried to
+redirect STDIN using '<'. Only one STDIN stream to a customer, please.
+
+=item '|' and '>' may not both be specified on command line
+
+(F) An error peculiar to VMS. Perl does its own command line
+redirection, and thinks you tried to redirect stdout both to a file and
+into a pipe to another command. You need to choose one or the other,
+though nothing's stopping you from piping into a program or Perl script
+which 'splits' output into two streams, such as
+
+ open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
+ while (<STDIN>) {
+ print;
+ print OUT;
+ }
+ close OUT;
+
+=item Applying %s to %s will act on scalar(%s)
+
+(W misc) The pattern match (C<//>), substitution (C<s///>), and
+transliteration (C<tr///>) operators work on scalar values. If you apply
+one of them to an array or a hash, it will convert the array or hash to
+a scalar value (the length of an array, or the population info of a
+hash) and then work on that scalar value. This is probably not what
+you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
+alternatives.
+
+=item Args must match #! line
+
+(F) The setuid emulator requires that the arguments Perl was invoked
+with match the arguments specified on the #! line. Since some systems
+impose a one-argument limit on the #! line, try combining switches;
+for example, turn C<-w -U> into C<-wU>.
+
+=item Arg too short for msgsnd
+
+(F) msgsnd() requires a string at least as long as sizeof(long).
+
+=item %s argument is not a HASH or ARRAY element or a subroutine
+
+(F) The argument to exists() must be a hash or array element or a
+subroutine with an ampersand, such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+ &do_something
+
+=item %s argument is not a HASH or ARRAY element or slice
+
+(F) The argument to delete() must be either a hash or array element,
+such as:
+
+ $foo{$bar}
+ $ref->{"susie"}[12]
+
+or a hash or array slice, such as:
+
+ @foo[$bar, $baz, $xyzzy]
+ @{$ref->[12]}{"susie", "queue"}
+
+=item %s argument is not a subroutine name
+
+(F) The argument to exists() for C<exists &sub> must be a subroutine
+name, and not a subroutine call. C<exists &sub()> will generate this
+error.
+
+=item Argument "%s" isn't numeric%s
+
+(W numeric) The indicated string was fed as an argument to an operator
+that expected a numeric value instead. If you're fortunate the message
+will identify which operator was so unfortunate.
+
+=item Argument list not closed for PerlIO layer "%s"
+
+(W layer) When pushing a layer with arguments onto the Perl I/O system you
+forgot the ) that closes the argument list. (Layers take care of transforming
+data between external and internal representations.) Perl stopped parsing
+the layer list at this point and did not attempt to push this layer.
+If your program didn't explicitly request the failing operation, it may be
+the result of the value of the environment variable PERLIO.
+
+=item Array @%s missing the @ in argument %d of %s()
+
+(D deprecated) Really old Perl let you omit the @ on array names in some
+spots. This is now heavily deprecated.
+
+=item assertion botched: %s
+
+(P) The malloc package that comes with Perl had an internal failure.
+
+=item Assertion failed: file "%s"
+
+(P) A general assertion failed. The file in question must be examined.
+
+=item Assignment to both a list and a scalar
+
+(F) If you assign to a conditional operator, the 2nd and 3rd arguments
+must either both be scalars or both be lists. Otherwise Perl won't
+know which context to supply to the right side.
+
+=item A thread exited while %d threads were running
+
+(W threads)(S) When using threaded Perl, a thread (not necessarily the main
+thread) exited while there were still other threads running.
+Usually it's a good idea to first collect the return values of the
+created threads by joining them, and only then exit from the main
+thread. See L<threads>.
+
+=item Attempt to access disallowed key '%s' in a restricted hash
+
+(F) The failing code has attempted to get or set a key which is not in
+the current set of allowed keys of a restricted hash.
+
+=item Attempt to bless into a reference
+
+(F) The CLASSNAME argument to the bless() operator is expected to be
+the name of the package to bless the resulting object into. You've
+supplied instead a reference to something: perhaps you wrote
+
+ bless $self, $proto;
+
+when you intended
+
+ bless $self, ref($proto) || $proto;
+
+If you actually want to bless into the stringified version
+of the reference supplied, you need to stringify it yourself, for
+example by:
+
+ bless $self, "$proto";
+
+=item Attempt to delete disallowed key '%s' from a restricted hash
+
+(F) The failing code attempted to delete from a restricted hash a key
+which is not in its key set.
+
+=item Attempt to delete readonly key '%s' from a restricted hash
+
+(F) The failing code attempted to delete a key whose value has been
+declared readonly from a restricted hash.
+
+=item Attempt to free non-arena SV: 0x%lx
+
+(P internal) All SV objects are supposed to be allocated from arenas
+that will be garbage collected on exit. An SV was discovered to be
+outside any of those arenas.
+
+=item Attempt to free nonexistent shared string
+
+(P internal) Perl maintains a reference counted internal table of
+strings to optimize the storage and access of hash keys and other
+strings. This indicates someone tried to decrement the reference count
+of a string that can no longer be found in the table.
+
+=item Attempt to free temp prematurely
+
+(W debugging) Mortalized values are supposed to be freed by the
+free_tmps() routine. This indicates that something else is freeing the
+SV before the free_tmps() routine gets a chance, which means that the
+free_tmps() routine will be freeing an unreferenced scalar when it does
+try to free it.
+
+=item Attempt to free unreferenced glob pointers
+
+(P internal) The reference counts got screwed up on symbol aliases.
+
+=item Attempt to free unreferenced scalar
+
+(W internal) Perl went to decrement the reference count of a scalar to
+see if it would go to 0, and discovered that it had already gone to 0
+earlier, and should have been freed, and in fact, probably was freed.
+This could indicate that SvREFCNT_dec() was called too many times, or
+that SvREFCNT_inc() was called too few times, or that the SV was
+mortalized when it shouldn't have been, or that memory has been
+corrupted.
+
+=item Attempt to join self
+
+(F) You tried to join a thread from within itself, which is an
+impossible task. You may be joining the wrong thread, or you may need
+to move the join() to some other thread.
+
+=item Attempt to pack pointer to temporary value
+
+(W pack) You tried to pass a temporary value (like the result of a
+function, or a computed expression) to the "p" pack() template. This
+means the result contains a pointer to a location that could become
+invalid anytime, even before the end of the current statement. Use
+literals or global values as arguments to the "p" pack() template to
+avoid this warning.
+
+=item Attempt to reload %s aborted.
+
+(F) You tried to load a file with C<use> or C<require> that failed to
+compile once already. Perl will not try to compile this file again
+unless you delete its entry from %INC. See L<perlfunc/require> and
+L<perlvar/%INC>.
+
+=item Attempt to set length of freed array
+
+(W) You tried to set the length of an array which has been freed. You
+can do this by storing a reference to the scalar representing the last index
+of an array and later assigning through that reference. For example
+
+ $r = do {my @a; \$#a};
+ $$r = 503
+
+=item Attempt to use reference as lvalue in substr
+
+(W substr) You supplied a reference as the first argument to substr()
+used as an lvalue, which is pretty strange. Perhaps you forgot to
+dereference it first. See L<perlfunc/substr>.
+
+=item Attribute "locked" is deprecated
+
+(D deprecated) You have used the attributes pragam to modify the "locked"
+attribute on a code reference. The :locked attribute is obsolete, has had no
+effect since 5005 threads were removed, and will be removed in the next major
+release of Perl 5.
+
+=item Attribute "unique" is deprecated
+
+(D deprecated) You have used the attributes pragam to modify the "unique"
+attribute on an array, hash or scalar reference. The :unique attribute has
+had no effect since Perl 5.8.8, and will be removed in the next major
+release of Perl 5.
+
+=item Bad arg length for %s, is %d, should be %d
+
+(F) You passed a buffer of the wrong size to one of msgctl(), semctl()
+or shmctl(). In C parlance, the correct sizes are, respectively,
+S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
+S<sizeof(struct shmid_ds *)>.
+
+=item Bad evalled substitution pattern
+
+(F) You've used the C</e> switch to evaluate the replacement for a
+substitution, but perl found a syntax error in the code to evaluate,
+most likely an unexpected right brace '}'.
+
+=item Bad filehandle: %s
+
+(F) A symbol was passed to something wanting a filehandle, but the
+symbol has no filehandle associated with it. Perhaps you didn't do an
+open(), or did it in another package.
+
+=item Bad free() ignored
+
+(S malloc) An internal routine called free() on something that had never
+been malloc()ed in the first place. Mandatory, but can be disabled by
+setting environment variable C<PERL_BADFREE> to 0.
+
+This message can be seen quite often with DB_File on systems with "hard"
+dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
+which is left unnoticed if C<DB> uses I<forgiving> system malloc().
+
+=item Bad hash
+
+(P) One of the internal hash routines was passed a null HV pointer.
+
+=item Badly placed ()'s
+
+(A) You've accidentally run your script through B<csh> instead
+of Perl. Check the #! line, or manually feed your script into
+Perl yourself.
+
+=item Bad name after %s::
+
+(F) You started to name a symbol by using a package prefix, and then
+didn't finish the symbol. In particular, you can't interpolate outside
+of quotes, so
+
+ $var = 'myvar';
+ $sym = mypack::$var;
+
+is not the same as
+
+ $var = 'myvar';
+ $sym = "mypack::$var";
+
+=item Bad plugin affecting keyword '%s'
+
+(F) An extension using the keyword plugin mechanism violated the
+plugin API.
+
+=item Bad realloc() ignored
+
+(S malloc) An internal routine called realloc() on something that had
+never been malloc()ed in the first place. Mandatory, but can be disabled
+by setting environment variable C<PERL_BADFREE> to 1.
+
+=item Bad symbol for array
+
+(P) An internal request asked to add an array entry to something that
+wasn't a symbol table entry.
+
+=item Bad symbol for dirhandle
+
+(P) An internal request asked to add a dirhandle entry to something
+that wasn't a symbol table entry.
+
+
+=item Bad symbol for filehandle
+
+(P) An internal request asked to add a filehandle entry to something
+that wasn't a symbol table entry.
+
+=item Bad symbol for hash
+
+(P) An internal request asked to add a hash entry to something that
+wasn't a symbol table entry.
+
+=item Bareword found in conditional
+
+(W bareword) The compiler found a bareword where it expected a
+conditional, which often indicates that an || or && was parsed as part
+of the last argument of the previous construct, for example:
+
+ open FOO || die;
+
+It may also indicate a misspelled constant that has been interpreted as
+a bareword:
+
+ use constant TYPO => 1;
+ if (TYOP) { print "foo" }
+
+The C<strict> pragma is useful in avoiding such errors.
+
+=item Bareword "%s" not allowed while "strict subs" in use
+
+(F) With "strict subs" in use, a bareword is only allowed as a
+subroutine identifier, in curly brackets or to the left of the "=>"
+symbol. Perhaps you need to predeclare a subroutine?
+
+=item Bareword "%s" refers to nonexistent package
+
+(W bareword) You used a qualified bareword of the form C<Foo::>, but the
+compiler saw no other uses of that namespace before that point. Perhaps
+you need to predeclare a package?
+
+=item BEGIN failed--compilation aborted
+
+(F) An untrapped exception was raised while executing a BEGIN
+subroutine. Compilation stops immediately and the interpreter is
+exited.
+
+=item BEGIN not safe after errors--compilation aborted
+
+(F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
+implies a C<BEGIN {}>) after one or more compilation errors had already
+occurred. Since the intended environment for the C<BEGIN {}> could not
+be guaranteed (due to the errors), and since subsequent code likely
+depends on its correct operation, Perl just gave up.
+
+=item \1 better written as $1
+
+(W syntax) Outside of patterns, backreferences live on as variables.
+The use of backslashes is grandfathered on the right-hand side of a
+substitution, but stylistically it's better to use the variable form
+because other Perl programmers will expect it, and it works better if
+there are more than 9 backreferences.
+
+=item Binary number > 0b11111111111111111111111111111111 non-portable
+
+(W portable) The binary number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item bind() on closed socket %s
+
+(W closed) You tried to do a bind on a closed socket. Did you forget to
+check the return value of your socket() call? See L<perlfunc/bind>.
+
+=item binmode() on closed filehandle %s
+
+(W unopened) You tried binmode() on a filehandle that was never opened.
+Check you control flow and number of arguments.
+
+=item Bit vector size > 32 non-portable
+
+(W portable) Using bit vector sizes larger than 32 is non-portable.
+
+=item Bizarre copy of %s in %s
+
+(P) Perl detected an attempt to copy an internal value that is not
+copyable.
+
+=item Buffer overflow in prime_env_iter: %s
+
+(W internal) A warning peculiar to VMS. While Perl was preparing to
+iterate over %ENV, it encountered a logical name or symbol definition
+which was too long, so it was truncated to the string shown.
+
+=item Callback called exit
+
+(F) A subroutine invoked from an external package via call_sv()
+exited by calling exit.
+
+=item %s() called too early to check prototype
+
+(W prototype) You've called a function that has a prototype before the
+parser saw a definition or declaration for it, and Perl could not check
+that the call conforms to the prototype. You need to either add an
+early prototype declaration for the subroutine in question, or move the
+subroutine definition ahead of the call to get proper prototype
+checking. Alternatively, if you are certain that you're calling the
+function correctly, you may put an ampersand before the name to avoid
+the warning. See L<perlsub>.
+
+=item Cannot compress integer in pack
+
+(F) An argument to pack("w",...) was too large to compress. The BER
+compressed integer format can only be used with positive integers, and you
+attempted to compress Infinity or a very large number (> 1e308).
+See L<perlfunc/pack>.
+
+=item Cannot compress negative numbers in pack
+
+(F) An argument to pack("w",...) was negative. The BER compressed integer
+format can only be used with positive integers. See L<perlfunc/pack>.
+
+=item Cannot convert a reference to %s to typeglob
+
+(F) You manipulated Perl's symbol table directly, stored a reference in it,
+then tried to access that symbol via conventional Perl syntax. The access
+triggers Perl to autovivify that typeglob, but it there is no legal conversion
+from that type of reference to a typeglob.
+
+=item Cannot copy to %s in %s
+
+(P) Perl detected an attempt to copy a value to an internal type that cannot
+be directly assigned not.
+
+=item Cannot find encoding "%s"
+
+(S io) You tried to apply an encoding that did not exist to a filehandle,
+either with open() or binmode().
+
+=item Can only compress unsigned integers in pack
+
+(F) An argument to pack("w",...) was not an integer. The BER compressed
+integer format can only be used with positive integers, and you attempted
+to compress something else. See L<perlfunc/pack>.
+
+=item Can't bless non-reference value
+
+(F) Only hard references may be blessed. This is how Perl "enforces"
+encapsulation of objects. See L<perlobj>.
+
+=item Can't "break" in a loop topicalizer
+
+(F) You called C<break>, but you're in a C<foreach> block rather than
+a C<given> block. You probably meant to use C<next> or C<last>.
+
+=item Can't "break" outside a given block
+
+(F) You called C<break>, but you're not inside a C<given> block.
+
+=item Can't call method "%s" in empty package "%s"
+
+(F) You called a method correctly, and it correctly indicated a package
+functioning as a class, but that package doesn't have ANYTHING defined
+in it, let alone methods. See L<perlobj>.
+
+=item Can't call method "%s" on an undefined value
+
+(F) You used the syntax of a method call, but the slot filled by the
+object reference or package name contains an undefined value. Something
+like this will reproduce the error:
+
+ $BADREF = undef;
+ process $BADREF 1,2,3;
+ $BADREF->process(1,2,3);
+
+=item Can't call method "%s" on unblessed reference
+
+(F) A method call must know in what package it's supposed to run. It
+ordinarily finds this out from the object reference you supply, but you
+didn't supply an object reference in this case. A reference isn't an
+object reference until it has been blessed. See L<perlobj>.
+
+=item Can't call method "%s" without a package or object reference
+
+(F) You used the syntax of a method call, but the slot filled by the
+object reference or package name contains an expression that returns a
+defined value which is neither an object reference nor a package name.
+Something like this will reproduce the error:
+
+ $BADREF = 42;
+ process $BADREF 1,2,3;
+ $BADREF->process(1,2,3);
+
+=item Can't chdir to %s
+
+(F) You called C<perl -x/foo/bar>, but C</foo/bar> is not a directory
+that you can chdir to, possibly because it doesn't exist.
+
+=item Can't check filesystem of script "%s" for nosuid
+
+(P) For some reason you can't check the filesystem of the script for
+nosuid.
+
+=item Can't coerce array into hash
+
+(F) You used an array where a hash was expected, but the array has no
+information on how to map from keys to array indices. You can do that
+only with arrays that have a hash reference at index 0.
+
+=item Can't coerce %s to integer in %s
+
+(F) Certain types of SVs, in particular real symbol table entries
+(typeglobs), can't be forced to stop being what they are. So you can't
+say things like:
+
+ *foo += 1;
+
+You CAN say
+
+ $foo = *foo;
+ $foo += 1;
+
+but then $foo no longer contains a glob.
+
+=item Can't coerce %s to number in %s
+
+(F) Certain types of SVs, in particular real symbol table entries
+(typeglobs), can't be forced to stop being what they are.
+
+=item Can't coerce %s to string in %s
+
+(F) Certain types of SVs, in particular real symbol table entries
+(typeglobs), can't be forced to stop being what they are.
+
+=item Can't "continue" outside a when block
+
+(F) You called C<continue>, but you're not inside a C<when>
+or C<default> block.
+
+=item Can't create pipe mailbox
+
+(P) An error peculiar to VMS. The process is suffering from exhausted
+quotas or other plumbing problems.
+
+=item Can't declare class for non-scalar %s in "%s"
+
+(F) Currently, only scalar variables can be declared with a specific
+class qualifier in a "my", "our" or "state" declaration. The semantics may be
+extended for other types of variables in future.
+
+=item Can't declare %s in "%s"
+
+(F) Only scalar, array, and hash variables may be declared as "my", "our" or
+"state" variables. They must have ordinary identifiers as names.
+
+=item Can't do inplace edit: %s is not a regular file
+
+(S inplace) You tried to use the B<-i> switch on a special file, such as
+a file in /dev, or a FIFO. The file was ignored.
+
+=item Can't do inplace edit on %s: %s
+
+(S inplace) The creation of the new file failed for the indicated
+reason.
+
+=item Can't do inplace edit without backup
+
+(F) You're on a system such as MS-DOS that gets confused if you try
+reading from a deleted (but still opened) file. You have to say
+C<-i.bak>, or some such.
+
+=item Can't do inplace edit: %s would not be unique
+
+(S inplace) Your filesystem does not support filenames longer than 14
+characters and Perl was unable to create a unique filename during
+inplace editing with the B<-i> switch. The file was ignored.
+
+=item Can't do {n,m} with n > m in regex; marked by <-- HERE in m/%s/
+
+(F) Minima must be less than or equal to maxima. If you really want your
+regexp to match something 0 times, just put {0}. The <-- HERE shows in the
+regular expression about where the problem was discovered. See L<perlre>.
+
+=item Can't do waitpid with flags
+
+(F) This machine doesn't have either waitpid() or wait4(), so only
+waitpid() without flags is emulated.
+
+=item Can't emulate -%s on #! line
+
+(F) The #! line specifies a switch that doesn't make sense at this
+point. For example, it'd be kind of silly to put a B<-x> on the #!
+line.
+
+=item Can't %s %s-endian %ss on this platform
+
+(F) Your platform's byte-order is neither big-endian nor little-endian,
+or it has a very strange pointer size. Packing and unpacking big- or
+little-endian floating point values and pointers may not be possible.
+See L<perlfunc/pack>.
+
+=item Can't exec "%s": %s
+
+(W exec) A system(), exec(), or piped open call could not execute the
+named program for the indicated reason. Typical reasons include: the
+permissions were wrong on the file, the file wasn't found in
+C<$ENV{PATH}>, the executable in question was compiled for another
+architecture, or the #! line in a script points to an interpreter that
+can't be run for similar reasons. (Or maybe your system doesn't support
+#! at all.)
+
+=item Can't exec %s
+
+(F) Perl was trying to execute the indicated program for you because
+that's what the #! line said. If that's not what you wanted, you may
+need to mention "perl" on the #! line somewhere.
+
+=item Can't execute %s
+
+(F) You used the B<-S> switch, but the copies of the script to execute
+found in the PATH did not have correct permissions.
+
+=item Can't find an opnumber for "%s"
+
+(F) A string of a form C<CORE::word> was given to prototype(), but there
+is no builtin with the name C<word>.
+
+=item Can't find %s character property "%s"
+
+(F) You used C<\p{}> or C<\P{}> but the character property by that name
+could not be found. Maybe you misspelled the name of the property?
+See L<perluniprops/Properties accessible through \p{} and \P{}>
+for a complete list of available properties.
+
+=item Can't find label %s
+
+(F) You said to goto a label that isn't mentioned anywhere that it's
+possible for us to go to. See L<perlfunc/goto>.
+
+=item Can't find %s on PATH
+
+(F) You used the B<-S> switch, but the script to execute could not be
+found in the PATH.
+
+=item Can't find %s on PATH, '.' not in PATH
+
+(F) You used the B<-S> switch, but the script to execute could not be
+found in the PATH, or at least not with the correct permissions. The
+script exists in the current directory, but PATH prohibits running it.
+
+=item Can't find string terminator %s anywhere before EOF
+
+(F) Perl strings can stretch over multiple lines. This message means
+that the closing delimiter was omitted. Because bracketed quotes count
+nesting levels, the following is missing its final parenthesis:
+
+ print q(The character '(' starts a side comment.);
+
+If you're getting this error from a here-document, you may have included
+unseen whitespace before or after your closing tag. A good programmer's
+editor will have a way to help you find these characters.
+
+=item Can't find Unicode property definition "%s"
+
+(F) You may have tried to use C<\p> which means a Unicode property (for
+example C<\p{Lu}> matches all uppercase letters). If you did mean to use a
+Unicode property, see
+L<perluniprops/Properties accessible through \p{} and \P{}>
+for a complete list of available properties.
+If you didn't mean to use a Unicode property, escape the C<\p>, either
+by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, until
+possible C<\E>).
+
+=item Can't fork: %s
+
+(F) A fatal error occurred while trying to fork while opening a
+pipeline.
+
+=item Can't fork, trying again in 5 seconds
+
+(W pipe) A fork in a piped open failed with EAGAIN and will be retried
+after five seconds.
+
+=item Can't get filespec - stale stat buffer?
+
+(S) A warning peculiar to VMS. This arises because of the difference
+between access checks under VMS and under the Unix model Perl assumes.
+Under VMS, access checks are done by filename, rather than by bits in
+the stat buffer, so that ACLs and other protections can be taken into
+account. Unfortunately, Perl assumes that the stat buffer contains all
+the necessary information, and passes it, instead of the filespec, to
+the access checking routine. It will try to retrieve the filespec using
+the device name and FID present in the stat buffer, but this works only
+if you haven't made a subsequent call to the CRTL stat() routine,
+because the device name is overwritten with each call. If this warning
+appears, the name lookup failed, and the access checking routine gave up
+and returned FALSE, just to be conservative. (Note: The access checking
+routine knows about the Perl C<stat> operator and file tests, so you
+shouldn't ever see this warning in response to a Perl command; it arises
+only if some internal code takes stat buffers lightly.)
+
+=item Can't get pipe mailbox device name
+
+(P) An error peculiar to VMS. After creating a mailbox to act as a
+pipe, Perl can't retrieve its name for later use.
+
+=item Can't get SYSGEN parameter value for MAXBUF
+
+(P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
+mailbox buffers to be, and didn't get an answer.
+
+=item Can't "goto" into the middle of a foreach loop
+
+(F) A "goto" statement was executed to jump into the middle of a foreach
+loop. You can't get there from here. See L<perlfunc/goto>.
+
+=item Can't "goto" out of a pseudo block
+
+(F) A "goto" statement was executed to jump out of what might look like
+a block, except that it isn't a proper block. This usually occurs if
+you tried to jump out of a sort() block or subroutine, which is a no-no.
+See L<perlfunc/goto>.
+
+=item Can't goto subroutine from a sort sub (or similar callback)
+
+(F) The "goto subroutine" call can't be used to jump out of the
+comparison sub for a sort(), or from a similar callback (such
+as the reduce() function in List::Util).
+
+=item Can't goto subroutine from an eval-%s
+
+(F) The "goto subroutine" call can't be used to jump out of an eval
+"string" or block.
+
+=item Can't goto subroutine outside a subroutine
+
+(F) The deeply magical "goto subroutine" call can only replace one
+subroutine call for another. It can't manufacture one out of whole
+cloth. In general you should be calling it out of only an AUTOLOAD
+routine anyway. See L<perlfunc/goto>.
+
+=item Can't ignore signal CHLD, forcing to default
+
+(W signal) Perl has detected that it is being run with the SIGCHLD
+signal (sometimes known as SIGCLD) disabled. Since disabling this
+signal will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value. This
+situation typically indicates that the parent program under which Perl
+may be running (e.g. cron) is being very careless.
+
+=item Can't kill a non-numeric process ID
+
+(F) Process identifiers must be (signed) integers. It is a fatal error to
+attempt to kill() an undefined, empty-string or otherwise non-numeric
+process identifier.
+
+=item Can't "last" outside a loop block
+
+(F) A "last" statement was executed to break out of the current block,
+except that there's this itty bitty problem called there isn't a current
+block. Note that an "if" or "else" block doesn't count as a "loopish"
+block, as doesn't a block given to sort(), map() or grep(). You can
+usually double the curlies to get the same effect though, because the
+inner curlies will be considered a block that loops once. See
+L<perlfunc/last>.
+
+=item Can't linearize anonymous symbol table
+
+(F) Perl tried to calculate the method resolution order (MRO) of a
+package, but failed because the package stash has no name.
+
+=item Can't load '%s' for module %s
+
+(F) The module you tried to load failed to load a dynamic extension. This
+may either mean that you upgraded your version of perl to one that is
+incompatible with your old dynamic extensions (which is known to happen
+between major versions of perl), or (more likely) that your dynamic
+extension was built against an older version of the library that is
+installed on your system. You may need to rebuild your old dynamic
+extensions.
+
+=item Can't localize lexical variable %s
+
+(F) You used local on a variable name that was previously declared as a
+lexical variable using "my" or "state". This is not allowed. If you want to
+localize a package variable of the same name, qualify it with the
+package name.
+
+=item Can't localize through a reference
+
+(F) You said something like C<local $$ref>, which Perl can't currently
+handle, because when it goes to restore the old value of whatever $ref
+pointed to after the scope of the local() is finished, it can't be sure
+that $ref will still be a reference.
+
+=item Can't locate %s
+
+(F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be
+found. Perl looks for the file in all the locations mentioned in @INC,
+unless the file name included the full path to the file. Perhaps you
+need to set the PERL5LIB or PERL5OPT environment variable to say where
+the extra library is, or maybe the script needs to add the library name
+to @INC. Or maybe you just misspelled the name of the file. See
+L<perlfunc/require> and L<lib>.
+
+=item Can't locate auto/%s.al in @INC
+
+(F) A function (or method) was called in a package which allows
+autoload, but there is no function to autoload. Most probable causes
+are a misprint in a function/method name or a failure to C<AutoSplit>
+the file, say, by doing C<make install>.
+
+=item Can't locate loadable object for module %s in @INC
+
+(F) The module you loaded is trying to load an external library, like
+for example, C<foo.so> or C<bar.dll>, but the L<DynaLoader> module was
+unable to locate this library. See L<DynaLoader>.
+
+=item Can't locate object method "%s" via package "%s"
+
+(F) You called a method correctly, and it correctly indicated a package
+functioning as a class, but that package doesn't define that particular
+method, nor does any of its base classes. See L<perlobj>.
+
+=item Can't locate package %s for @%s::ISA
+
+(W syntax) The @ISA array contained the name of another package that
+doesn't seem to exist.
+
+=item Can't locate PerlIO%s
+
+(F) You tried to use in open() a PerlIO layer that does not exist,
+e.g. open(FH, ">:nosuchlayer", "somefile").
+
+=item Can't make list assignment to \%ENV on this system
+
+(F) List assignment to %ENV is not supported on some systems, notably
+VMS.
+
+=item Can't modify %s in %s
+
+(F) You aren't allowed to assign to the item indicated, or otherwise try
+to change it, such as with an auto-increment.
+
+=item Can't modify nonexistent substring
+
+(P) The internal routine that does assignment to a substr() was handed
+a NULL.
+
+=item Can't modify non-lvalue subroutine call
+
+(F) Subroutines meant to be used in lvalue context should be declared as
+such, see L<perlsub/"Lvalue subroutines">.
+
+=item Can't msgrcv to read-only var
+
+(F) The target of a msgrcv must be modifiable to be used as a receive
+buffer.
+
+=item Can't "next" outside a loop block
+
+(F) A "next" statement was executed to reiterate the current block, but
+there isn't a current block. Note that an "if" or "else" block doesn't
+count as a "loopish" block, as doesn't a block given to sort(), map() or
+grep(). You can usually double the curlies to get the same effect
+though, because the inner curlies will be considered a block that loops
+once. See L<perlfunc/next>.
+
+=item Can't open %s: %s
+
+(S inplace) The implicit opening of a file through use of the C<< <> >>
+filehandle, either implicitly under the C<-n> or C<-p> command-line
+switches, or explicitly, failed for the indicated reason. Usually this
+is because you don't have read permission for a file which you named on
+the command line.
+
+=item Can't open a reference
+
+(W io) You tried to open a scalar reference for reading or writing,
+using the 3-arg open() syntax :
+
+ open FH, '>', $ref;
+
+but your version of perl is compiled without perlio, and this form of
+open is not supported.
+
+=item Can't open bidirectional pipe
+
+(W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
+You can try any of several modules in the Perl library to do this, such
+as IPC::Open2. Alternately, direct the pipe's output to a file using
+">", and then read it in under a different file handle.
+
+=item Can't open error file %s as stderr
+
+(F) An error peculiar to VMS. Perl does its own command line
+redirection, and couldn't open the file specified after '2>' or '2>>' on
+the command line for writing.
+
+=item Can't open input file %s as stdin
+
+(F) An error peculiar to VMS. Perl does its own command line
+redirection, and couldn't open the file specified after '<' on the
+command line for reading.
+
+=item Can't open output file %s as stdout
+
+(F) An error peculiar to VMS. Perl does its own command line
+redirection, and couldn't open the file specified after '>' or '>>' on
+the command line for writing.
+
+=item Can't open output pipe (name: %s)
+
+(P) An error peculiar to VMS. Perl does its own command line
+redirection, and couldn't open the pipe into which to send data destined
+for stdout.
+
+=item Can't open perl script%s
+
+(F) The script you specified can't be opened for the indicated reason.
+
+If you're debugging a script that uses #!, and normally relies on the
+shell's $PATH search, the -S option causes perl to do that search, so
+you don't have to type the path or C<`which $scriptname`>.
+
+=item Can't read CRTL environ
+
+(S) A warning peculiar to VMS. Perl tried to read an element of %ENV
+from the CRTL's internal environment array and discovered the array was
+missing. You need to figure out where your CRTL misplaced its environ
+or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
+searched.
+
+=item Can't "redo" outside a loop block
+
+(F) A "redo" statement was executed to restart the current block, but
+there isn't a current block. Note that an "if" or "else" block doesn't
+count as a "loopish" block, as doesn't a block given to sort(), map()
+or grep(). You can usually double the curlies to get the same effect
+though, because the inner curlies will be considered a block that
+loops once. See L<perlfunc/redo>.
+
+=item Can't remove %s: %s, skipping file
+
+(S inplace) You requested an inplace edit without creating a backup
+file. Perl was unable to remove the original file to replace it with
+the modified file. The file was left unmodified.
+
+=item Can't rename %s to %s: %s, skipping file
+
+(S inplace) The rename done by the B<-i> switch failed for some reason,
+probably because you don't have write permission to the directory.
+
+=item Can't reopen input pipe (name: %s) in binary mode
+
+(P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
+to reopen it to accept binary data. Alas, it failed.
+
+=item Can't resolve method "%s" overloading "%s" in package "%s"
+
+(F|P) Error resolving overloading specified by a method name (as opposed
+to a subroutine reference): no such method callable via the package. If
+method name is C<???>, this is an internal error.
+
+=item Can't return %s from lvalue subroutine
+
+(F) Perl detected an attempt to return illegal lvalues (such as
+temporary or readonly values) from a subroutine used as an lvalue. This
+is not allowed.
+
+=item Can't return outside a subroutine
+
+(F) The return statement was executed in mainline code, that is, where
+there was no subroutine call to return out of. See L<perlsub>.
+
+=item Can't return %s to lvalue scalar context
+
+(F) You tried to return a complete array or hash from an lvalue subroutine,
+but you called the subroutine in a way that made Perl think you meant
+to return only one value. You probably meant to write parentheses around
+the call to the subroutine, which tell Perl that the call should be in
+list context.
+
+=item Can't stat script "%s"
+
+(P) For some reason you can't fstat() the script even though you have it
+open already. Bizarre.
+
+=item Can't take log of %g
+
+(F) For ordinary real numbers, you can't take the logarithm of a
+negative number or zero. There's a Math::Complex package that comes
+standard with Perl, though, if you really want to do that for the
+negative numbers.
+
+=item Can't take sqrt of %g
+
+(F) For ordinary real numbers, you can't take the square root of a
+negative number. There's a Math::Complex package that comes standard
+with Perl, though, if you really want to do that.
+
+=item Can't undef active subroutine
+
+(F) You can't undefine a routine that's currently running. You can,
+however, redefine it while it's running, and you can even undef the
+redefined subroutine while the old routine is running. Go figure.
+
+=item Can't unshift
+
+(F) You tried to unshift an "unreal" array that can't be unshifted, such
+as the main Perl stack.
+
+=item Can't upgrade %s (%d) to %d
+
+(P) The internal sv_upgrade routine adds "members" to an SV, making it
+into a more specialized kind of SV. The top several SV types are so
+specialized, however, that they cannot be interconverted. This message
+indicates that such a conversion was attempted.
+
+=item Can't use anonymous symbol table for method lookup
+
+(F) The internal routine that does method lookup was handed a symbol
+table that doesn't have a name. Symbol tables can become anonymous
+for example by undefining stashes: C<undef %Some::Package::>.
+
+=item Can't use an undefined value as %s reference
+
+(F) A value used as either a hard reference or a symbolic reference must
+be a defined value. This helps to delurk some insidious errors.
+
+=item Can't use bareword ("%s") as %s ref while "strict refs" in use
+
+(F) Only hard references are allowed by "strict refs". Symbolic
+references are disallowed. See L<perlref>.
+
+=item Can't use %! because Errno.pm is not available
+
+(F) The first time the %! hash is used, perl automatically loads the
+Errno.pm module. The Errno module is expected to tie the %! hash to
+provide symbolic names for C<$!> errno values.
+
+=item Can't use both '<' and '>' after type '%c' in %s
+
+(F) A type cannot be forced to have both big-endian and little-endian
+byte-order at the same time, so this combination of modifiers is not
+allowed. See L<perlfunc/pack>.
+
+=item Can't use %s for loop variable
+
+(F) Only a simple scalar variable may be used as a loop variable on a
+foreach.
+
+=item Can't use global %s in "%s"
+
+(F) You tried to declare a magical variable as a lexical variable. This
+is not allowed, because the magic can be tied to only one location
+(namely the global variable) and it would be incredibly confusing to
+have variables in your program that looked like magical variables but
+weren't.
+
+=item Can't use '%c' in a group with different byte-order in %s
+
+(F) You attempted to force a different byte-order on a type
+that is already inside a group with a byte-order modifier.
+For example you cannot force little-endianness on a type that
+is inside a big-endian group.
+
+=item Can't use "my %s" in sort comparison
+
+(F) The global variables $a and $b are reserved for sort comparisons.
+You mentioned $a or $b in the same line as the <=> or cmp operator,
+and the variable had earlier been declared as a lexical variable.
+Either qualify the sort variable with the package name, or rename the
+lexical variable.
+
+=item Can't use %s ref as %s ref
+
+(F) You've mixed up your reference types. You have to dereference a
+reference of the type needed. You can use the ref() function to
+test the type of the reference, if need be.
+
+=item Can't use string ("%s") as %s ref while "strict refs" in use
+
+(F) Only hard references are allowed by "strict refs". Symbolic
+references are disallowed. See L<perlref>.
+
+=item Can't use subscript on %s
+
+(F) The compiler tried to interpret a bracketed expression as a
+subscript. But to the left of the brackets was an expression that
+didn't look like a hash or array reference, or anything else subscriptable.
+
+=item Can't use \%c to mean $%c in expression
+
+(W syntax) In an ordinary expression, backslash is a unary operator that
+creates a reference to its argument. The use of backslash to indicate a
+backreference to a matched substring is valid only as part of a regular
+expression pattern. Trying to do this in ordinary Perl code produces a
+value that prints out looking like SCALAR(0xdecaf). Use the $1 form
+instead.
+
+=item Can't use "when" outside a topicalizer
+
+(F) You have used a when() block that is neither inside a C<foreach>
+loop nor a C<given> block. (Note that this error is issued on exit
+from the C<when> block, so you won't get the error if the match fails,
+or if you use an explicit C<continue>.)
+
+=item Can't weaken a nonreference
+
+(F) You attempted to weaken something that was not a reference. Only
+references can be weakened.
+
+=item Can't x= to read-only value
+
+(F) You tried to repeat a constant value (often the undefined value)
+with an assignment operator, which implies modifying the value itself.
+Perhaps you need to copy the value to a temporary, and repeat that.
+
+=item Character in 'C' format wrapped in pack
+
+(W pack) You said
+
+ pack("C", $x)
+
+where $x is either less than 0 or more than 255; the C<"C"> format is
+only for encoding native operating system characters (ASCII, EBCDIC,
+and so on) and not for Unicode characters, so Perl behaved as if you meant
+
+ pack("C", $x & 255)
+
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
+
+=item Character in 'W' format wrapped in pack
+
+(W pack) You said
+
+ pack("U0W", $x)
+
+where $x is either less than 0 or more than 255. However, C<U0>-mode expects
+all values to fall in the interval [0, 255], so Perl behaved as if you
+meant:
+
+ pack("U0W", $x & 255)
+
+=item Character in 'c' format wrapped in pack
+
+(W pack) You said
+
+ pack("c", $x)
+
+where $x is either less than -128 or more than 127; the C<"c"> format
+is only for encoding native operating system characters (ASCII, EBCDIC,
+and so on) and not for Unicode characters, so Perl behaved as if you meant
+
+ pack("c", $x & 255);
+
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
+
+=item Character in '%c' format wrapped in unpack
+
+(W unpack) You tried something like
+
+ unpack("H", "\x{2a1}")
+
+where the format expects to process a byte (a character with a value
+below 256), but a higher value was provided instead. Perl uses the value
+modulus 256 instead, as if you had provided:
+
+ unpack("H", "\x{a1}")
+
+=item Character(s) in '%c' format wrapped in pack
+
+(W pack) You tried something like
+
+ pack("u", "\x{1f3}b")
+
+where the format expects to process a sequence of bytes (character with a
+value below 256), but some of the characters had a higher value. Perl
+uses the character values modulus 256 instead, as if you had provided:
+
+ pack("u", "\x{f3}b")
+
+=item Character(s) in '%c' format wrapped in unpack
+
+(W unpack) You tried something like
+
+ unpack("s", "\x{1f3}b")
+
+where the format expects to process a sequence of bytes (character with a
+value below 256), but some of the characters had a higher value. Perl
+uses the character values modulus 256 instead, as if you had provided:
+
+ unpack("s", "\x{f3}b")
+
+=item close() on unopened filehandle %s
+
+(W unopened) You tried to close a filehandle that was never opened.
+
+=item closedir() attempted on invalid dirhandle %s
+
+(W io) The dirhandle you tried to close is either closed or not really
+a dirhandle. Check your control flow.
+
+=item Code missing after '/'
+
+(F) You had a (sub-)template that ends with a '/'. There must be another
+template code following the slash. See L<perlfunc/pack>.
+
+=item %s: Command not found
+
+(A) You've accidentally run your script through B<csh> instead of Perl.
+Check the #! line, or manually feed your script into Perl yourself.
+
+=item Compilation failed in require
+
+(F) Perl could not compile a file specified in a C<require> statement.
+Perl uses this generic message when none of the errors that it
+encountered were severe enough to halt compilation immediately.
+
+=item Complex regular subexpression recursion limit (%d) exceeded
+
+(W regexp) The regular expression engine uses recursion in complex
+situations where back-tracking is required. Recursion depth is limited
+to 32766, or perhaps less in architectures where the stack cannot grow
+arbitrarily. ("Simple" and "medium" situations are handled without
+recursion and are not subject to a limit.) Try shortening the string
+under examination; looping in Perl code (e.g. with C<while>) rather than
+in the regular expression engine; or rewriting the regular expression so
+that it is simpler or backtracks less. (See L<perlfaq2> for information
+on I<Mastering Regular Expressions>.)
+
+=item cond_broadcast() called on unlocked variable
+
+(W threads) Within a thread-enabled program, you tried to call
+cond_broadcast() on a variable which wasn't locked. The cond_broadcast()
+function is used to wake up another thread that is waiting in a
+cond_wait(). To ensure that the signal isn't sent before the other thread
+has a chance to enter the wait, it is usual for the signaling thread to
+first wait for a lock on variable. This lock attempt will only succeed
+after the other thread has entered cond_wait() and thus relinquished the
+lock.
+
+=item cond_signal() called on unlocked variable
+
+(W threads) Within a thread-enabled program, you tried to call
+cond_signal() on a variable which wasn't locked. The cond_signal()
+function is used to wake up another thread that is waiting in a
+cond_wait(). To ensure that the signal isn't sent before the other thread
+has a chance to enter the wait, it is usual for the signaling thread to
+first wait for a lock on variable. This lock attempt will only succeed
+after the other thread has entered cond_wait() and thus relinquished the
+lock.
+
+=item connect() on closed socket %s
+
+(W closed) You tried to do a connect on a closed socket. Did you forget
+to check the return value of your socket() call? See
+L<perlfunc/connect>.
+
+=item Constant(%s)%s: %s
+
+(F) The parser found inconsistencies either while attempting to define
+an overloaded constant, or when trying to find the character name
+specified in the C<\N{...}> escape. Perhaps you forgot to load the
+corresponding C<overload> or C<charnames> pragma? See L<charnames> and
+L<overload>.
+
+=item Constant(%s)%s: %s in regex; marked by <-- HERE in m/%s/
+
+(F) The parser found inconsistencies while attempting to find
+the character name specified in the C<\N{...}> escape. Perhaps you
+forgot to load the corresponding C<charnames> pragma?
+See L<charnames>.
+
+
+=item Constant is not %s reference
+
+(F) A constant value (perhaps declared using the C<use constant> pragma)
+is being dereferenced, but it amounts to the wrong type of reference.
+The message indicates the type of reference that was expected. This
+usually indicates a syntax error in dereferencing the constant value.
+See L<perlsub/"Constant Functions"> and L<constant>.
+
+=item Constant subroutine %s redefined
+
+(S) You redefined a subroutine which had previously been
+eligible for inlining. See L<perlsub/"Constant Functions"> for
+commentary and workarounds.
+
+=item Constant subroutine %s undefined
+
+(W misc) You undefined a subroutine which had previously been eligible
+for inlining. See L<perlsub/"Constant Functions"> for commentary and
+workarounds.
+
+=item Copy method did not return a reference
+
+(F) The method which overloads "=" is buggy. See
+L<overload/Copy Constructor>.
+
+=item CORE::%s is not a keyword
+
+(F) The CORE:: namespace is reserved for Perl keywords.
+
+=item corrupted regexp pointers
+
+(P) The regular expression engine got confused by what the regular
+expression compiler gave it.
+
+=item corrupted regexp program
+
+(P) The regular expression engine got passed a regexp program without a
+valid magic number.
+
+=item Corrupt malloc ptr 0x%lx at 0x%lx
+
+(P) The malloc package that comes with Perl had an internal failure.
+
+=item Count after length/code in unpack
+
+(F) You had an unpack template indicating a counted-length string, but
+you have also specified an explicit size for the string. See
+L<perlfunc/pack>.
+
+=item Deep recursion on subroutine "%s"
+
+(W recursion) This subroutine has called itself (directly or indirectly)
+100 times more than it has returned. This probably indicates an
+infinite recursion, unless you're writing strange benchmark programs, in
+which case it indicates something else.
+
+This threshold can be changed from 100, by recompiling the F<perl> binary,
+setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
+
+=item defined(@array) is deprecated
+
+(D deprecated) defined() is not usually useful on arrays because it
+checks for an undefined I<scalar> value. If you want to see if the
+array is empty, just use C<if (@array) { # not empty }> for example.
+
+=item defined(%hash) is deprecated
+
+(D deprecated) defined() is not usually useful on hashes because it
+checks for an undefined I<scalar> value. If you want to see if the hash
+is empty, just use C<if (%hash) { # not empty }> for example.
+
+=item %s defines neither package nor VERSION--version check failed
+
+(F) You said something like "use Module 42" but in the Module file
+there are neither package declarations nor a C<$VERSION>.
+
+=item Delimiter for here document is too long
+
+(F) In a here document construct like C<<<FOO>, the label C<FOO> is too
+long for Perl to handle. You have to be seriously twisted to write code
+that triggers this error.
+
+=item Deprecated character(s) in \\N{...} starting at '%s'
+
+(D deprecated) Just about anything is legal for the C<...> in C<\N{...}>.
+But starting in 5.12, non-reasonable ones that don't look like names are
+deprecated. A reasonable name begins with an alphabetic character and
+continues with any combination of alphanumerics, dashes, spaces, parentheses or
+colons.
+
+=item Deprecated use of my() in false conditional
+
+(D deprecated) You used a declaration similar to C<my $x if 0>.
+There has been a long-standing bug in Perl that causes a lexical variable
+not to be cleared at scope exit when its declaration includes a false
+conditional. Some people have exploited this bug to achieve a kind of
+static variable. Since we intend to fix this bug, we don't want people
+relying on this behavior. You can achieve a similar static effect by
+declaring the variable in a separate block outside the function, eg
+
+ sub f { my $x if 0; return $x++ }
+
+becomes
+
+ { my $x; sub f { return $x++ } }
+
+Beginning with perl 5.9.4, you can also use C<state> variables to
+have lexicals that are initialized only once (see L<feature>):
+
+ sub f { state $x; return $x++ }
+
+=item DESTROY created new reference to dead object '%s'
+
+(F) A DESTROY() method created a new reference to the object which is
+just being DESTROYed. Perl is confused, and prefers to abort rather than
+to create a dangling reference.
+
+=item Did not produce a valid header
+
+See Server error.
+
+=item %s did not return a true value
+
+(F) A required (or used) file must return a true value to indicate that
+it compiled correctly and ran its initialization code correctly. It's
+traditional to end such a file with a "1;", though any true value would
+do. See L<perlfunc/require>.
+
+=item (Did you mean &%s instead?)
+
+(W) You probably referred to an imported subroutine &FOO as $FOO or some
+such.
+
+=item (Did you mean "local" instead of "our"?)
+
+(W misc) Remember that "our" does not localize the declared global
+variable. You have declared it again in the same lexical scope, which
+seems superfluous.
+
+=item (Did you mean $ or @ instead of %?)
+
+(W) You probably said %hash{$key} when you meant $hash{$key} or
+@hash{@keys}. On the other hand, maybe you just meant %hash and got
+carried away.
+
+=item Died
+
+(F) You passed die() an empty string (the equivalent of C<die "">) or
+you called it with no args and both C<$@> and C<$_> were empty.
+
+=item Document contains no data
+
+See Server error.
+
+=item %s does not define %s::VERSION--version check failed
+
+(F) You said something like "use Module 42" but the Module did not
+define a C<$VERSION.>
+
+=item '/' does not take a repeat count
+
+(F) You cannot put a repeat count of any kind right after the '/' code.
+See L<perlfunc/pack>.
+
+=item Don't know how to handle magic of type '%s'
+
+(P) The internal handling of magical variables has been cursed.
+
+=item do_study: out of memory
+
+(P) This should have been caught by safemalloc() instead.
+
+=item (Do you need to predeclare %s?)
+
+(S syntax) This is an educated guess made in conjunction with the message
+"%s found where operator expected". It often means a subroutine or module
+name is being referenced that hasn't been declared yet. This may be
+because of ordering problems in your file, or because of a missing
+"sub", "package", "require", or "use" statement. If you're referencing
+something that isn't defined yet, you don't actually have to define the
+subroutine or package before the current location. You can use an empty
+"sub foo;" or "package FOO;" to enter a "forward" declaration.
+
+=item dump() better written as CORE::dump()
+
+(W misc) You used the obsolescent C<dump()> built-in function, without fully
+qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
+
+=item dump is not supported
+
+(F) Your machine doesn't support dump/undump.
+
+=item Duplicate free() ignored
+
+(S malloc) An internal routine called free() on something that had
+already been freed.
+
+=item Duplicate modifier '%c' after '%c' in %s
+
+(W) You have applied the same modifier more than once after a type
+in a pack template. See L<perlfunc/pack>.
+
+=item elseif should be elsif
+
+(S syntax) There is no keyword "elseif" in Perl because Larry thinks it's
+ugly. Your code will be interpreted as an attempt to call a method named
+"elseif" for the class returned by the following block. This is
+unlikely to be what you want.
+
+=item Empty %s
+
+(F) C<\p> and C<\P> are used to introduce a named Unicode property, as
+described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
+a regular expression without specifying the property name.
+
+=item entering effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item %ENV is aliased to %s
+
+(F) You're running under taint mode, and the C<%ENV> variable has been
+aliased to another hash, so it doesn't reflect anymore the state of the
+program's environment. This is potentially insecure.
+
+=item Error converting file specification %s
+
+(F) An error peculiar to VMS. Because Perl may have to deal with file
+specifications in either VMS or Unix syntax, it converts them to a
+single form when it must operate on them directly. Either you've passed
+an invalid file specification to Perl, or you've found a case the
+conversion routines don't handle. Drat.
+
+=item %s: Eval-group in insecure regular expression
+
+(F) Perl detected tainted data when trying to compile a regular
+expression that contains the C<(?{ ... })> zero-width assertion, which
+is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
+
+=item %s: Eval-group not allowed at runtime, use re 'eval'
+
+(F) Perl tried to compile a regular expression containing the
+C<(?{ ... })> zero-width assertion at run time, as it would when the
+pattern contains interpolated values. Since that is a security risk, it
+is not allowed. If you insist, you may still do this by explicitly
+building the pattern from an interpolated string at run time and using
+that in an eval(). See L<perlre/(?{ code })>.
+
+=item %s: Eval-group not allowed, use re 'eval'
+
+(F) A regular expression contained the C<(?{ ... })> zero-width
+assertion, but that construct is only allowed when the C<use re 'eval'>
+pragma is in effect. See L<perlre/(?{ code })>.
+
+=item EVAL without pos change exceeded limit in regex; marked by <-- HERE in m/%s/
+
+(F) You used a pattern that nested too many EVAL calls without consuming
+any text. Restructure the pattern so that text is consumed.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Excessively long <> operator
+
+(F) The contents of a <> operator may not exceed the maximum size of a
+Perl identifier. If you're just trying to glob a long list of
+filenames, try using the glob() operator, or put the filenames into a
+variable and glob that.
+
+=item exec? I'm not *that* kind of operating system
+
+(F) The C<exec> function is not implemented in MacPerl. See L<perlport>.
+
+=item Execution of %s aborted due to compilation errors.
+
+(F) The final summary message when a Perl compilation fails.
+
+=item Exiting eval via %s
+
+(W exiting) You are exiting an eval by unconventional means, such as a
+goto, or a loop control statement.
+
+=item Exiting format via %s
+
+(W exiting) You are exiting a format by unconventional means, such as a
+goto, or a loop control statement.
+
+=item Exiting pseudo-block via %s
+
+(W exiting) You are exiting a rather special block construct (like a
+sort block or subroutine) by unconventional means, such as a goto, or a
+loop control statement. See L<perlfunc/sort>.
+
+=item Exiting subroutine via %s
+
+(W exiting) You are exiting a subroutine by unconventional means, such
+as a goto, or a loop control statement.
+
+=item Exiting substitution via %s
+
+(W exiting) You are exiting a substitution by unconventional means, such
+as a return, a goto, or a loop control statement.
+
+=item Explicit blessing to '' (assuming package main)
+
+(W misc) You are blessing a reference to a zero length string. This has
+the effect of blessing the reference into the package main. This is
+usually not what you want. Consider providing a default target package,
+e.g. bless($ref, $p || 'MyPackage');
+
+=item %s: Expression syntax
+
+(A) You've accidentally run your script through B<csh> instead of Perl.
+Check the #! line, or manually feed your script into Perl yourself.
+
+=item %s failed--call queue aborted
+
+(F) An untrapped exception was raised while executing a UNITCHECK,
+CHECK, INIT, or END subroutine. Processing of the remainder of the
+queue of such routines has been prematurely ended.
+
+=item False [] range "%s" in regex; marked by <-- HERE in m/%s/
+
+(W regexp) A character class range must start and end at a literal
+character, not another character class like C<\d> or C<[:alpha:]>. The "-"
+in your false range is interpreted as a literal "-". Consider quoting the
+"-", "\-". The <-- HERE shows in the regular expression about where the
+problem was discovered. See L<perlre>.
+
+=item Fatal VMS error at %s, line %d
+
+(P) An error peculiar to VMS. Something untoward happened in a VMS
+system service or RTL routine; Perl's exit status should provide more
+details. The filename in "at %s" and the line number in "line %d" tell
+you which section of the Perl source code is distressed.
+
+=item fcntl is not implemented
+
+(F) Your machine apparently doesn't implement fcntl(). What is this, a
+PDP-11 or something?
+
+=item FETCHSIZE returned a negative value
+
+(F) A tied array claimed to have a negative number of elements, which
+is not possible.
+
+=item Field too wide in 'u' format in pack
+
+(W pack) Each line in an uuencoded string start with a length indicator
+which can't encode values above 63. So there is no point in asking for
+a line length bigger than that. Perl will behave as if you specified
+C<u63> as format.
+
+=item Filehandle %s opened only for input
+
+(W io) You tried to write on a read-only filehandle. If you intended
+it to be a read-write filehandle, you needed to open it with "+<" or
+"+>" or "+>>" instead of with "<" or nothing. If you intended only to
+write the file, use ">" or ">>". See L<perlfunc/open>.
+
+=item Filehandle %s opened only for output
+
+(W io) You tried to read from a filehandle opened only for writing, If
+you intended it to be a read/write filehandle, you needed to open it
+with "+<" or "+>" or "+>>" instead of with "<" or nothing. If you
+intended only to read from the file, use "<". See L<perlfunc/open>.
+Another possibility is that you attempted to open filedescriptor 0
+(also known as STDIN) for output (maybe you closed STDIN earlier?).
+
+=item Filehandle %s reopened as %s only for input
+
+(W io) You opened for reading a filehandle that got the same filehandle id
+as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
+previously.
+
+=item Filehandle STDIN reopened as %s only for output
+
+(W io) You opened for writing a filehandle that got the same filehandle id
+as STDIN. This occurred because you closed STDIN previously.
+
+=item Final $ should be \$ or $name
+
+(F) You must now decide whether the final $ in a string was meant to be
+a literal dollar sign, or was meant to introduce a variable name that
+happens to be missing. So you have to put either the backslash or the
+name.
+
+=item flock() on closed filehandle %s
+
+(W closed) The filehandle you're attempting to flock() got itself closed
+some time before now. Check your control flow. flock() operates on
+filehandles. Are you attempting to call flock() on a dirhandle by the
+same name?
+
+=item Format not terminated
+
+(F) A format must be terminated by a line with a solitary dot. Perl got
+to the end of your file without finding such a line.
+
+=item Format %s redefined
+
+(W redefine) You redefined a format. To suppress this warning, say
+
+ {
+ no warnings 'redefine';
+ eval "format NAME =...";
+ }
+
+=item Found = in conditional, should be ==
+
+(W syntax) You said
+
+ if ($foo = 123)
+
+when you meant
+
+ if ($foo == 123)
+
+(or something like that).
+
+=item %s found where operator expected
+
+(S syntax) The Perl lexer knows whether to expect a term or an operator.
+If it sees what it knows to be a term when it was expecting to see an
+operator, it gives you this warning. Usually it indicates that an
+operator or delimiter was omitted, such as a semicolon.
+
+=item gdbm store returned %d, errno %d, key "%s"
+
+(S) A warning from the GDBM_File extension that a store failed.
+
+=item gethostent not implemented
+
+(F) Your C library apparently doesn't implement gethostent(), probably
+because if it did, it'd feel morally obligated to return every hostname
+on the Internet.
+
+=item get%sname() on closed socket %s
+
+(W closed) You tried to get a socket or peer socket name on a closed
+socket. Did you forget to check the return value of your socket() call?
+
+=item getpwnam returned invalid UIC %#o for user "%s"
+
+(S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
+C<getpwnam> operator returned an invalid UIC.
+
+=item getsockopt() on closed socket %s
+
+(W closed) You tried to get a socket option on a closed socket. Did you
+forget to check the return value of your socket() call? See
+L<perlfunc/getsockopt>.
+
+=item Global symbol "%s" requires explicit package name
+
+(F) You've said "use strict" or "use strict vars", which indicates
+that all variables must either be lexically scoped (using "my" or "state"),
+declared beforehand using "our", or explicitly qualified to say
+which package the global variable is in (using "::").
+
+=item glob failed (%s)
+
+(W glob) Something went wrong with the external program(s) used for
+C<glob> and C<< <*.c> >>. Usually, this means that you supplied a
+C<glob> pattern that caused the external program to fail and exit with a
+nonzero status. If the message indicates that the abnormal exit
+resulted in a coredump, this may also mean that your csh (C shell) is
+broken. If so, you should change all of the csh-related variables in
+config.sh: If you have tcsh, make the variables refer to it as if it
+were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all
+empty (except that C<d_csh> should be C<'undef'>) so that Perl will
+think csh is missing. In either case, after editing config.sh, run
+C<./Configure -S> and rebuild Perl.
+
+=item Glob not terminated
+
+(F) The lexer saw a left angle bracket in a place where it was expecting
+a term, so it's looking for the corresponding right angle bracket, and
+not finding it. Chances are you left some needed parentheses out
+earlier in the line, and you really meant a "less than".
+
+=item gmtime(%.0f) too large
+
+(W overflow) You called C<gmtime> with an number that was larger than
+it can reliably handle and C<gmtime> probably returned the wrong
+date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item gmtime(%.0f) too small
+
+(W overflow) You called C<gmtime> with an number that was smaller than
+it can reliably handle and C<gmtime> probably returned the wrong
+date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item Got an error from DosAllocMem
+
+(P) An error peculiar to OS/2. Most probably you're using an obsolete
+version of Perl, and this should not happen anyway.
+
+=item goto must have label
+
+(F) Unlike with "next" or "last", you're not allowed to goto an
+unspecified destination. See L<perlfunc/goto>.
+
+=item ()-group starts with a count
+
+(F) A ()-group started with a count. A count is
+supposed to follow something: a template character or a ()-group.
+ See L<perlfunc/pack>.
+
+=item %s had compilation errors.
+
+(F) The final summary message when a C<perl -c> fails.
+
+=item Had to create %s unexpectedly
+
+(S internal) A routine asked for a symbol from a symbol table that ought
+to have existed already, but for some reason it didn't, and had to be
+created on an emergency basis to prevent a core dump.
+
+=item Hash %%s missing the % in argument %d of %s()
+
+(D deprecated) Really old Perl let you omit the % on hash names in some
+spots. This is now heavily deprecated.
+
+=item %s has too many errors
+
+(F) The parser has given up trying to parse the program after 10 errors.
+Further error messages would likely be uninformative.
+
+=item Hexadecimal number > 0xffffffff non-portable
+
+(W portable) The hexadecimal number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+=item Identifier too long
+
+(F) Perl limits identifiers (names for variables, functions, etc.) to
+about 250 characters for simple names, and somewhat more for compound
+names (like C<$A::B>). You've exceeded Perl's limits. Future versions
+of Perl are likely to eliminate these arbitrary limitations.
+
+=item Ignoring zero length \N{} in character class
+
+(W) Named Unicode character escapes (\N{...}) may return a
+zero length sequence. When such an escape is used in a character class
+its behaviour is not well defined. Check that the correct escape has
+been used, and the correct charname handler is in scope.
+
+=item Illegal binary digit %s
+
+(F) You used a digit other than 0 or 1 in a binary number.
+
+=item Illegal binary digit %s ignored
+
+(W digit) You may have tried to use a digit other than 0 or 1 in a
+binary number. Interpretation of the binary number stopped before the
+offending digit.
+
+=item Illegal character %s (carriage return)
+
+(F) Perl normally treats carriage returns in the program text as it
+would any other whitespace, which means you should never see this error
+when Perl was built using standard options. For some reason, your
+version of Perl appears to have been built without this support. Talk
+to your Perl administrator.
+
+=item Illegal character in prototype for %s : %s
+
+(W illegalproto) An illegal character was found in a prototype declaration.
+Legal characters in prototypes are $, @, %, *, ;, [, ], &, and \.
+
+=item Illegal declaration of anonymous subroutine
+
+(F) When using the C<sub> keyword to construct an anonymous subroutine,
+you must always specify a block of code. See L<perlsub>.
+
+=item Illegal declaration of subroutine %s
+
+(F) A subroutine was not declared correctly. See L<perlsub>.
+
+=item Illegal division by zero
+
+(F) You tried to divide a number by 0. Either something was wrong in
+your logic, or you need to put a conditional in to guard against
+meaningless input.
+
+=item Illegal hexadecimal digit %s ignored
+
+(W digit) You may have tried to use a character other than 0 - 9 or
+A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
+number stopped before the illegal character.
+
+=item Illegal modulus zero
+
+(F) You tried to divide a number by 0 to get the remainder. Most
+numbers don't take to this kindly.
+
+=item Illegal number of bits in vec
+
+(F) The number of bits in vec() (the third argument) must be a power of
+two from 1 to 32 (or 64, if your platform supports that).
+
+=item Illegal octal digit %s
+
+(F) You used an 8 or 9 in an octal number.
+
+=item Illegal octal digit %s ignored
+
+(W digit) You may have tried to use an 8 or 9 in an octal number.
+Interpretation of the octal number stopped before the 8 or 9.
+
+=item Illegal switch in PERL5OPT: -%c
+
+(X) The PERL5OPT environment variable may only be used to set the
+following switches: B<-[CDIMUdmtw]>.
+
+=item Ill-formed CRTL environ value "%s"
+
+(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
+internal environ array, and encountered an element without the C<=>
+delimiter used to separate keys from values. The element is ignored.
+
+=item Ill-formed message in prime_env_iter: |%s|
+
+(W internal) A warning peculiar to VMS. Perl tried to read a logical
+name or CLI symbol definition when preparing to iterate over %ENV, and
+didn't see the expected delimiter between key and value, so the line was
+ignored.
+
+=item (in cleanup) %s
+
+(W misc) This prefix usually indicates that a DESTROY() method raised
+the indicated exception. Since destructors are usually called by the
+system at arbitrary points during execution, and often a vast number of
+times, the warning is issued only once for any number of failures that
+would otherwise result in the same message being repeated.
+
+Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
+also result in this warning. See L<perlcall/G_KEEPERR>.
+
+=item Inconsistent hierarchy during C3 merge of class '%s': merging failed on parent '%s'
+
+(F) The method resolution order (MRO) of the given class is not
+C3-consistent, and you have enabled the C3 MRO for this class. See the C3
+documentation in L<mro> for more information.
+
+=item In EBCDIC the v-string components cannot exceed 2147483647
+
+(F) An error peculiar to EBCDIC. Internally, v-strings are stored as
+Unicode code points, and encoded in EBCDIC as UTF-EBCDIC. The UTF-EBCDIC
+encoding is limited to code points no larger than 2147483647 (0x7FFFFFFF).
+
+=item Infinite recursion in regex; marked by <-- HERE in m/%s/
+
+(F) You used a pattern that references itself without consuming any input
+text. You should check the pattern to ensure that recursive patterns
+either consume text or fail.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Initialization of state variables in list context currently forbidden
+
+(F) Currently the implementation of "state" only permits the initialization
+of scalar variables in scalar context. Re-write C<state ($a) = 42> as
+C<state $a = 42> to change from list to scalar context. Constructions such
+as C<state (@a) = foo()> will be supported in a future perl release.
+
+=item Insecure dependency in %s
+
+(F) You tried to do something that the tainting mechanism didn't like.
+The tainting mechanism is turned on when you're running setuid or
+setgid, or when you specify B<-T> to turn it on explicitly. The
+tainting mechanism labels all data that's derived directly or indirectly
+from the user, who is considered to be unworthy of your trust. If any
+such data is used in a "dangerous" operation, you get this error. See
+L<perlsec> for more information.
+
+=item Insecure directory in %s
+
+(F) You can't use system(), exec(), or a piped open in a setuid or
+setgid script if C<$ENV{PATH}> contains a directory that is writable by
+the world. Also, the PATH must not contain any relative directory.
+See L<perlsec>.
+
+=item Insecure $ENV{%s} while running %s
+
+(F) You can't use system(), exec(), or a piped open in a setuid or
+setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
+C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
+supplied (or potentially supplied) by the user. The script must set
+the path to a known value, using trustworthy data. See L<perlsec>.
+
+=item Integer overflow in %s number
+
+(W overflow) The hexadecimal, octal or binary number you have specified
+either as a literal or as an argument to hex() or oct() is too big for
+your architecture, and has been converted to a floating point number.
+On a 32-bit architecture the largest hexadecimal, octal or binary number
+representable without overflow is 0xFFFFFFFF, 037777777777, or
+0b11111111111111111111111111111111 respectively. Note that Perl
+transparently promotes all numbers to a floating point representation
+internally--subject to loss of precision errors in subsequent
+operations.
+
+=item Integer overflow in format string for %s
+
+(F) The indexes and widths specified in the format string of C<printf()>
+or C<sprintf()> are too large. The numbers must not overflow the size of
+integers for your architecture.
+
+=item Integer overflow in version
+
+(F) Some portion of a version initialization is too large for the
+size of integers for your architecture. This is not a warning
+because there is no rational reason for a version to try and use a
+element larger than typically 2**32. This is usually caused by
+trying to use some odd mathematical operation as a version, like
+100/9.
+
+=item Internal disaster in regex; marked by <-- HERE in m/%s/
+
+(P) Something went badly wrong in the regular expression parser.
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Internal inconsistency in tracking vforks
+
+(S) A warning peculiar to VMS. Perl keeps track of the number of times
+you've called C<fork> and C<exec>, to determine whether the current call
+to C<exec> should affect the current script or a subprocess (see
+L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
+Perl is making a guess and treating this C<exec> as a request to
+terminate the Perl script and execute the specified command.
+
+=item Internal urp in regex; marked by <-- HERE in m/%s/
+
+(P) Something went badly awry in the regular expression parser. The
+<-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item %s (...) interpreted as function
+
+(W syntax) You've run afoul of the rule that says that any list operator
+followed by parentheses turns into a function, with all the list
+operators arguments found inside the parentheses. See
+L<perlop/Terms and List Operators (Leftward)>.
+
+=item Invalid %s attribute: %s
+
+The indicated attribute for a subroutine or variable was not recognized
+by Perl or by a user-supplied handler. See L<attributes>.
+
+=item Invalid %s attributes: %s
+
+The indicated attributes for a subroutine or variable were not
+recognized by Perl or by a user-supplied handler. See L<attributes>.
+
+=item Invalid conversion in %s: "%s"
+
+(W printf) Perl does not understand the given format conversion. See
+L<perlfunc/sprintf>.
+
+=item Invalid escape in the specified encoding in regex; marked by <-- HERE in m/%s/
+
+(W regexp) The numeric escape (for example C<\xHH>) of value < 256
+didn't correspond to a single character through the conversion
+from the encoding specified by the encoding pragma.
+The escape was replaced with REPLACEMENT CHARACTER (U+FFFD) instead.
+The <-- HERE shows in the regular expression about where the
+escape was discovered.
+
+=item Invalid mro name: '%s'
+
+(F) You tried to C<mro::set_mro("classname", "foo")>
+or C<use mro 'foo'>, where C<foo> is not a valid method resolution order (MRO).
+(Currently, the only valid ones are C<dfs> and C<c3>). See L<mro>.
+
+=item Invalid [] range "%s" in regex; marked by <-- HERE in m/%s/
+
+(F) The range specified in a character class had a minimum character
+greater than the maximum character. One possibility is that you forgot the
+C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
+up to C<ff>. The <-- HERE shows in the regular expression about where the
+problem was discovered. See L<perlre>.
+
+=item Invalid range "%s" in transliteration operator
+
+(F) The range specified in the tr/// or y/// operator had a minimum
+character greater than the maximum character. See L<perlop>.
+
+=item Invalid separator character %s in attribute list
+
+(F) Something other than a colon or whitespace was seen between the
+elements of an attribute list. If the previous attribute had a
+parenthesised parameter list, perhaps that list was terminated too soon.
+See L<attributes>.
+
+=item Invalid separator character %s in PerlIO layer specification %s
+
+(W layer) When pushing layers onto the Perl I/O system, something other than a
+colon or whitespace was seen between the elements of a layer list.
+If the previous attribute had a parenthesised parameter list, perhaps that
+list was terminated too soon.
+
+=item Invalid type '%s' in %s
+
+(F) The given character is not a valid pack or unpack type.
+See L<perlfunc/pack>.
+(W) The given character is not a valid pack or unpack type but used to be
+silently ignored.
+
+=item Invalid version format (multiple underscores)
+
+(F) Versions may contain at most a single underscore, which signals
+that the version is a beta release. See L<version> for the allowed
+version formats.
+
+=item Invalid version format (underscores before decimal)
+
+(F) Versions may not contain decimals after the optional underscore.
+See L<version> for the allowed version formats.
+
+=item ioctl is not implemented
+
+(F) Your machine apparently doesn't implement ioctl(), which is pretty
+strange for a machine that supports C.
+
+=item ioctl() on unopened %s
+
+(W unopened) You tried ioctl() on a filehandle that was never opened.
+Check you control flow and number of arguments.
+
+=item IO layers (like '%s') unavailable
+
+(F) Your Perl has not been configured to have PerlIO, and therefore
+you cannot use IO layers. To have PerlIO Perl must be configured
+with 'useperlio'.
+
+=item IO::Socket::atmark not implemented on this architecture
+
+(F) Your machine doesn't implement the sockatmark() functionality,
+neither as a system call or an ioctl call (SIOCATMARK).
+
+=item $* is no longer supported
+
+(D deprecated, syntax) The special variable C<$*>, deprecated in older perls, has
+been removed as of 5.9.0 and is no longer supported. In previous versions of perl the use of
+C<$*> enabled or disabled multi-line matching within a string.
+
+Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
+modifiers. (In older versions: when C<$*> was set to a true value then all regular
+expressions behaved as if they were written using C</m>.)
+
+=item $# is no longer supported
+
+(D deprecated, syntax) The special variable C<$#>, deprecated in older perls, has
+been removed as of 5.9.3 and is no longer supported. You should use the
+printf/sprintf functions instead.
+
+=item `%s' is not a code reference
+
+(W overload) The second (fourth, sixth, ...) argument of overload::constant
+needs to be a code reference. Either an anonymous subroutine, or a reference
+to a subroutine.
+
+=item `%s' is not an overloadable type
+
+(W overload) You tried to overload a constant type the overload package is
+unaware of.
+
+=item junk on end of regexp
+
+(P) The regular expression parser is confused.
+
+=item Label not found for "last %s"
+
+(F) You named a loop to break out of, but you're not currently in a loop
+of that name, not even if you count where you were called from. See
+L<perlfunc/last>.
+
+=item Label not found for "next %s"
+
+(F) You named a loop to continue, but you're not currently in a loop of
+that name, not even if you count where you were called from. See
+L<perlfunc/last>.
+
+=item Label not found for "redo %s"
+
+(F) You named a loop to restart, but you're not currently in a loop of
+that name, not even if you count where you were called from. See
+L<perlfunc/last>.
+
+=item leaving effective %s failed
+
+(F) While under the C<use filetest> pragma, switching the real and
+effective uids or gids failed.
+
+=item length/code after end of string in unpack
+
+(F) While unpacking, the string buffer was already used up when an unpack
+length/code combination tried to obtain more data. This results in
+an undefined value for the length. See L<perlfunc/pack>.
+
+=item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
+
+(F) An extension is attempting to insert text into the current parse
+(using L<lex_stuff_pvn_flags|perlapi/lex_stuff_pvn_flags> or similar), but
+tried to insert a character that couldn't be part of the current input.
+This is an inherent pitfall of the stuffing mechanism, and one of the
+reasons to avoid it. Where it is necessary to stuff, stuffing only
+plain ASCII is recommended.
+
+=item Lexing code internal error (%s)
+
+(F) Lexing code supplied by an extension violated the lexer's API in a
+detectable way.
+
+=item listen() on closed socket %s
+
+(W closed) You tried to do a listen on a closed socket. Did you forget
+to check the return value of your socket() call? See
+L<perlfunc/listen>.
+
+=item localtime(%.0f) too large
+
+(W overflow) You called C<localtime> with an number that was larger
+than it can reliably handle and C<localtime> probably returned the
+wrong date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item localtime(%.0f) too small
+
+(W overflow) You called C<localtime> with an number that was smaller
+than it can reliably handle and C<localtime> probably returned the
+wrong date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item Lookbehind longer than %d not implemented in regex m/%s/
+
+(F) There is currently a limit on the length of string which lookbehind can
+handle. This restriction may be eased in a future release.
+
+=item Lost precision when %s %f by 1
+
+(W) The value you attempted to increment or decrement by one is too large
+for the underlying floating point representation to store accurately,
+hence the target of C<++> or C<--> is unchanged. Perl issues this warning
+because it has already switched from integers to floating point when values
+are too large for integers, and now even floating point is insufficient.
+You may wish to switch to using L<Math::BigInt> explicitly.
+
+=item lstat() on filehandle %s
+
+(W io) You tried to do an lstat on a filehandle. What did you mean
+by that? lstat() makes sense only on filenames. (Perl did a fstat()
+instead on the filehandle.)
+
+=item lvalue attribute ignored after the subroutine has been defined
+
+(W misc) Making a subroutine an lvalue subroutine after it has been defined
+by declaring the subroutine with a lvalue attribute is not
+possible. To make the the subroutine a lvalue subroutine add the
+lvalue attribute to the definition, or put the the declaration before
+the definition.
+
+=item Lvalue subs returning %s not implemented yet
+
+(F) Due to limitations in the current implementation, array and hash
+values cannot be returned in subroutines used in lvalue context. See
+L<perlsub/"Lvalue subroutines">.
+
+=item Malformed integer in [] in pack
+
+(F) Between the brackets enclosing a numeric repeat count only digits
+are permitted. See L<perlfunc/pack>.
+
+=item Malformed integer in [] in unpack
+
+(F) Between the brackets enclosing a numeric repeat count only digits
+are permitted. See L<perlfunc/pack>.
+
+=item Malformed PERLLIB_PREFIX
+
+(F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
+
+ prefix1;prefix2
+
+or
+ prefix1 prefix2
+
+with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
+a builtin library search path, prefix2 is substituted. The error may
+appear if components are not found, or are too long. See
+"PERLLIB_PREFIX" in L<perlos2>.
+
+=item Malformed prototype for %s: %s
+
+(F) You tried to use a function with a malformed prototype. The
+syntax of function prototypes is given a brief compile-time check for
+obvious errors like invalid characters. A more rigorous check is run
+when the function is called.
+
+=item Malformed UTF-8 character (%s)
+
+(S utf8) (F) Perl detected a string that didn't comply with UTF-8
+encoding rules, even though it had the UTF8 flag on.
+
+One possible cause is that you set the UTF8 flag yourself for data that
+you thought to be in UTF-8 but it wasn't (it was for example legacy
+8-bit data). To guard against this, you can use Encode::decode_utf8.
+
+If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
+sequences are handled gracefully, but if you use C<:utf8>, the flag is
+set without validating the data, possibly resulting in this error
+message.
+
+See also L<Encode/"Handling Malformed Data">.
+
+=item Malformed UTF-16 surrogate
+
+(F) Perl thought it was reading UTF-16 encoded character data but while
+doing it Perl met a malformed Unicode surrogate.
+
+=item Malformed UTF-8 returned by \N
+
+(F) The charnames handler returned malformed UTF-8.
+
+=item Malformed UTF-8 string in pack
+
+(F) You tried to pack something that didn't comply with UTF-8 encoding
+rules and perl was unable to guess how to make more progress.
+
+=item Malformed UTF-8 string in unpack
+
+(F) You tried to unpack something that didn't comply with UTF-8 encoding
+rules and perl was unable to guess how to make more progress.
+
+=item Malformed UTF-8 string in '%c' format in unpack
+
+(F) You tried to unpack something that didn't comply with UTF-8 encoding
+rules and perl was unable to guess how to make more progress.
+
+=item Maximal count of pending signals (%d) exceeded
+
+(F) Perl aborted due to a too high number of signals pending. This
+usually indicates that your operating system tried to deliver signals
+too fast (with a very high priority), starving the perl process from
+resources it would need to reach a point where it can process signals
+safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
+
+=item %s matches null string many times in regex; marked by <-- HERE in m/%s/
+
+(W regexp) The pattern you've specified would be an infinite loop if the
+regular expression engine didn't specifically check for that. The <-- HERE
+shows in the regular expression about where the problem was discovered.
+See L<perlre>.
+
+=item "%s" may clash with future reserved word
+
+(W) This warning may be due to running a perl5 script through a perl4
+interpreter, especially if the word that is being warned about is
+"use" or "my".
+
+=item % may not be used in pack
+
+(F) You can't pack a string by supplying a checksum, because the
+checksumming process loses information, and you can't go the other way.
+See L<perlfunc/unpack>.
+
+=item Method for operation %s not found in package %s during blessing
+
+(F) An attempt was made to specify an entry in an overloading table that
+doesn't resolve to a valid subroutine. See L<overload>.
+
+=item Method %s not permitted
+
+See Server error.
+
+=item Might be a runaway multi-line %s string starting on line %d
+
+(S) An advisory indicating that the previous error may have been caused
+by a missing delimiter on a string or pattern, because it eventually
+ended earlier on the current line.
+
+=item Misplaced _ in number
+
+(W syntax) An underscore (underbar) in a numeric constant did not
+separate two digits.
+
+=item Missing argument in %s
+
+(W uninitialized) A printf-type format required more arguments than were
+supplied.
+
+=item Missing argument to -%c
+
+(F) The argument to the indicated command line switch must follow
+immediately after the switch, without intervening spaces.
+
+=item Missing braces on \N{}
+
+(F) Wrong syntax of character name literal C<\N{charname}> within
+double-quotish context. This can also happen when there is a space (or
+comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
+This modifier does not change the requirement that the brace immediately follow
+the C<\N>.
+
+=item Missing comma after first argument to %s function
+
+(F) While certain functions allow you to specify a filehandle or an
+"indirect object" before the argument list, this ain't one of them.
+
+=item Missing command in piped open
+
+(W pipe) You used the C<open(FH, "| command")> or
+C<open(FH, "command |")> construction, but the command was missing or
+blank.
+
+=item Missing control char name in \c
+
+(F) A double-quoted string ended with "\c", without the required control
+character name.
+
+=item Missing name in "my sub"
+
+(F) The reserved syntax for lexically scoped subroutines requires that
+they have a name with which they can be found.
+
+=item Missing $ on loop variable
+
+(F) Apparently you've been programming in B<csh> too much. Variables
+are always mentioned with the $ in Perl, unlike in the shells, where it
+can vary from one line to the next.
+
+=item (Missing operator before %s?)
+
+(S syntax) This is an educated guess made in conjunction with the message
+"%s found where operator expected". Often the missing operator is a comma.
+
+=item Missing right brace on %s
+
+(F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
+
+=item Missing right brace on \\N{} or unescaped left brace after \\N
+
+(F)
+C<\N> has two meanings.
+
+The traditional one has it followed by a name enclosed
+in braces, meaning the character (or sequence of characters) given by that name.
+Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
+double-quoted strings and regular expression patterns. In patterns, it doesn't
+have the meaning an unescaped C<*> does.
+
+Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only) in
+patterns, namely to match a non-newline character. (This is short for
+C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
+
+This can lead to some ambiguities. When C<\N> is not followed immediately by a
+left brace, Perl assumes the C<[^\n]> meaning. Also, if
+the braces form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes
+that this means to match the given quantity of non-newlines (in these examples,
+3; and 5 or more, respectively). In all other case, where there is a C<\N{>
+and a matching C<}>, Perl assumes that a character name is desired.
+
+However, if there is no matching C<}>, Perl doesn't know if it was mistakenly
+omitted, or if C<[^\n]{> was desired, and
+raises this error. If you meant the former, add the right brace; if you meant
+the latter, escape the brace with a backslash, like so: C<\N\{>
+
+=item Missing right curly or square bracket
+
+(F) The lexer counted more opening curly or square brackets than closing
+ones. As a general rule, you'll find it's missing near the place you
+were last editing.
+
+=item (Missing semicolon on previous line?)
+
+(S syntax) This is an educated guess made in conjunction with the message
+"%s found where operator expected". Don't automatically put a semicolon on
+the previous line just because you saw this message.
+
+=item Modification of a read-only value attempted
+
+(F) You tried, directly or indirectly, to change the value of a
+constant. You didn't, of course, try "2 = 1", because the compiler
+catches that. But an easy way to do the same thing is:
+
+ sub mod { $_[0] = 1 }
+ mod(2);
+
+Another way is to assign to a substr() that's off the end of the string.
+
+Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
+is aliased to a constant in the look I<LIST>:
+
+ $x = 1;
+ foreach my $n ($x, 2) {
+ $n *= 2; # modifies the $x, but fails on attempt to modify the 2
+ }
+
+=item Modification of non-creatable array value attempted, %s
+
+(F) You tried to make an array value spring into existence, and the
+subscript was probably negative, even counting from end of the array
+backwards.
+
+=item Modification of non-creatable hash value attempted, %s
+
+(P) You tried to make a hash value spring into existence, and it
+couldn't be created for some peculiar reason.
+
+=item Module name must be constant
+
+(F) Only a bare module name is allowed as the first argument to a "use".
+
+=item Module name required with -%c option
+
+(F) The C<-M> or C<-m> options say that Perl should load some module, but
+you omitted the name of the module. Consult L<perlrun> for full details
+about C<-M> and C<-m>.
+
+=item More than one argument to '%s' open
+
+(F) The C<open> function has been asked to open multiple files. This
+can happen if you are trying to open a pipe to a command that takes a
+list of arguments, but have forgotten to specify a piped open mode.
+See L<perlfunc/open> for details.
+
+=item msg%s not implemented
+
+(F) You don't have System V message IPC on your system.
+
+=item Multidimensional syntax %s not supported
+
+(W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
+They're written like C<$foo[1][2][3]>, as in C.
+
+=item '/' must follow a numeric type in unpack
+
+(F) You had an unpack template that contained a '/', but this did not
+follow some unpack specification producing a numeric value.
+See L<perlfunc/pack>.
+
+=item "my sub" not yet implemented
+
+(F) Lexically scoped subroutines are not yet implemented. Don't try
+that yet.
+
+=item "%s" variable %s can't be in a package
+
+(F) Lexically scoped variables aren't in a package, so it doesn't make
+sense to try to declare one with a package qualifier on the front. Use
+local() if you want to localize a package variable.
+
+=item \\N in a character class must be a named character: \\N{...}
+
+(F) The new (5.12) meaning of C<\N> as C<[^\n]> is not valid in a bracketed
+character class, for the same reason that C<.> in a character class loses its
+specialness: it matches almost everything, which is probably not what you want.
+
+=item \\N{NAME} must be resolved by the lexer
+
+(F) When compiling a regex pattern, an unresolved named character or sequence
+was encountered. This can happen in any of several ways that bypass the lexer,
+such as using single-quotish context, or an extra backslash in double quotish:
+
+ $re = '\N{SPACE}'; # Wrong!
+ $re = "\\N{SPACE}"; # Wrong!
+ /$re/;
+
+Instead, use double-quotes with a single backslash:
+
+ $re = "\N{SPACE}"; # ok
+ /$re/;
+
+The lexer can be bypassed as well by creating the pattern from smaller
+components:
+
+ $re = '\N';
+ /${re}{SPACE}/; # Wrong!
+
+It's not a good idea to split a construct in the middle like this, and it
+doesn't work here. Instead use the solution above.
+
+Finally, the message also can happen under the C</x> regex modifier when the
+C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
+
+ /\N {SPACE}/x; # Wrong!
+ /\N{SPACE}/x; # ok
+
+=item Name "%s::%s" used only once: possible typo
+
+(W once) Typographical errors often show up as unique variable names.
+If you had a good reason for having a unique name, then just mention it
+again somehow to suppress the message. The C<our> declaration is
+provided for this purpose.
+
+NOTE: This warning detects symbols that have been used only once so $c, @c,
+%c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered
+the same; if a program uses $c only once but also uses any of the others it
+will not trigger this warning.
+
+=item Invalid hexadecimal number in \\N{U+...}
+
+(F) The character constant represented by C<...> is not a valid hexadecimal
+number. Either it is empty, or you tried to use a character other than 0 - 9
+or A - F, a - f in a hexadecimal number.
+
+=item Negative '/' count in unpack
+
+(F) The length count obtained from a length/code unpack operation was
+negative. See L<perlfunc/pack>.
+
+=item Negative length
+
+(F) You tried to do a read/write/send/recv operation with a buffer
+length that is less than 0. This is difficult to imagine.
+
+=item Negative offset to vec in lvalue context
+
+(F) When C<vec> is called in an lvalue context, the second argument must be
+greater than or equal to zero.
+
+=item Nested quantifiers in regex; marked by <-- HERE in m/%s/
+
+(F) You can't quantify a quantifier without intervening parentheses. So
+things like ** or +* or ?* are illegal. The <-- HERE shows in the regular
+expression about where the problem was discovered.
+
+Note that the minimal matching quantifiers, C<*?>, C<+?>, and
+C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
+
+=item %s never introduced
+
+(S internal) The symbol in question was declared but somehow went out of
+scope before it could possibly have been used.
+
+=item next::method/next::can/maybe::next::method cannot find enclosing method
+
+(F) C<next::method> needs to be called within the context of a
+real method in a real package, and it could not find such a context.
+See L<mro>.
+
+=item No %s allowed while running setuid
+
+(F) Certain operations are deemed to be too insecure for a setuid or
+setgid script to even be allowed to attempt. Generally speaking there
+will be another way to do what you want that is, if not secure, at least
+securable. See L<perlsec>.
+
+=item No comma allowed after %s
+
+(F) A list operator that has a filehandle or "indirect object" is not
+allowed to have a comma between that and the following arguments.
+Otherwise it'd be just another one of the arguments.
+
+One possible cause for this is that you expected to have imported a
+constant to your name space with B<use> or B<import> while no such
+importing took place, it may for example be that your operating system
+does not support that particular constant. Hopefully you did use an
+explicit import list for the constants you expect to see, please see
+L<perlfunc/use> and L<perlfunc/import>. While an explicit import list
+would probably have caught this error earlier it naturally does not
+remedy the fact that your operating system still does not support that
+constant. Maybe you have a typo in the constants of the symbol import
+list of B<use> or B<import> or in the constant name at the line where
+this error was triggered?
+
+=item No command into which to pipe on command line
+
+(F) An error peculiar to VMS. Perl handles its own command line
+redirection, and found a '|' at the end of the command line, so it
+doesn't know where you want to pipe the output from this command.
+
+=item No DB::DB routine defined
+
+(F) The currently executing code was compiled with the B<-d> switch, but
+for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
+module) didn't define a routine to be called at the beginning of each
+statement.
+
+=item No dbm on this machine
+
+(P) This is counted as an internal error, because every machine should
+supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
+
+=item No DB::sub routine defined
+
+(F) The currently executing code was compiled with the B<-d> switch, but
+for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
+module) didn't define a C<DB::sub> routine to be called at the beginning
+of each ordinary subroutine call.
+
+=item No B<-e> allowed in setuid scripts
+
+(F) A setuid script can't be specified by the user.
+
+=item No error file after 2> or 2>> on command line
+
+(F) An error peculiar to VMS. Perl handles its own command line
+redirection, and found a '2>' or a '2>>' on the command line, but can't
+find the name of the file to which to write data destined for stderr.
+
+=item No group ending character '%c' found in template
+
+(F) A pack or unpack template has an opening '(' or '[' without its
+matching counterpart. See L<perlfunc/pack>.
+
+=item No input file after < on command line
+
+(F) An error peculiar to VMS. Perl handles its own command line
+redirection, and found a '<' on the command line, but can't find the
+name of the file from which to read data for stdin.
+
+=item No #! line
+
+(F) The setuid emulator requires that scripts have a well-formed #! line
+even on machines that don't support the #! construct.
+
+=item No next::method '%s' found for %s
+
+(F) C<next::method> found no further instances of this method name
+in the remaining packages of the MRO of this class. If you don't want
+it throwing an exception, use C<maybe::next::method>
+or C<next::can>. See L<mro>.
+
+=item "no" not allowed in expression
+
+(F) The "no" keyword is recognized and executed at compile time, and
+returns no useful value. See L<perlmod>.
+
+=item No output file after > on command line
+
+(F) An error peculiar to VMS. Perl handles its own command line
+redirection, and found a lone '>' at the end of the command line, so it
+doesn't know where you wanted to redirect stdout.
+
+=item No output file after > or >> on command line
+
+(F) An error peculiar to VMS. Perl handles its own command line
+redirection, and found a '>' or a '>>' on the command line, but can't
+find the name of the file to which to write data destined for stdout.
+
+=item No package name allowed for variable %s in "our"
+
+(F) Fully qualified variable names are not allowed in "our"
+declarations, because that doesn't make much sense under existing
+semantics. Such syntax is reserved for future extensions.
+
+=item No Perl script found in input
+
+(F) You called C<perl -x>, but no line was found in the file beginning
+with #! and containing the word "perl".
+
+=item No setregid available
+
+(F) Configure didn't find anything resembling the setregid() call for
+your system.
+
+=item No setreuid available
+
+(F) Configure didn't find anything resembling the setreuid() call for
+your system.
+
+=item No %s specified for -%c
+
+(F) The indicated command line switch needs a mandatory argument, but
+you haven't specified one.
+
+=item No such class field "%s" in variable %s of type %s
+
+(F) You tried to access a key from a hash through the indicated typed variable
+but that key is not allowed by the package of the same type. The indicated
+package has restricted the set of allowed keys using the L<fields> pragma.
+
+=item No such class %s
+
+(F) You provided a class qualifier in a "my", "our" or "state" declaration, but
+this class doesn't exist at this point in your program.
+
+=item No such hook: %s
+
+(F) You specified a signal hook that was not recognized by Perl. Currently, Perl
+accepts C<__DIE__> and C<__WARN__> as valid signal hooks
+
+=item No such pipe open
+
+(P) An error peculiar to VMS. The internal routine my_pclose() tried to
+close a pipe which hadn't been opened. This should have been caught
+earlier as an attempt to close an unopened filehandle.
+
+=item No such signal: SIG%s
+
+(W signal) You specified a signal name as a subscript to %SIG that was
+not recognized. Say C<kill -l> in your shell to see the valid signal
+names on your system.
+
+=item Not a CODE reference
+
+(F) Perl was trying to evaluate a reference to a code value (that is, a
+subroutine), but found a reference to something else instead. You can
+use the ref() function to find out what kind of ref it really was. See
+also L<perlref>.
+
+=item Not a format reference
+
+(F) I'm not sure how you managed to generate a reference to an anonymous
+format, but this indicates you did, and that it didn't exist.
+
+=item Not a GLOB reference
+
+(F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
+symbol table entry that looks like C<*foo>), but found a reference to
+something else instead. You can use the ref() function to find out what
+kind of ref it really was. See L<perlref>.
+
+=item Not a HASH reference
+
+(F) Perl was trying to evaluate a reference to a hash value, but found a
+reference to something else instead. You can use the ref() function to
+find out what kind of ref it really was. See L<perlref>.
+
+=item Not an ARRAY reference
+
+(F) Perl was trying to evaluate a reference to an array value, but found
+a reference to something else instead. You can use the ref() function
+to find out what kind of ref it really was. See L<perlref>.
+
+=item Not a perl script
+
+(F) The setuid emulator requires that scripts have a well-formed #! line
+even on machines that don't support the #! construct. The line must
+mention perl.
+
+=item Not a SCALAR reference
+
+(F) Perl was trying to evaluate a reference to a scalar value, but found
+a reference to something else instead. You can use the ref() function
+to find out what kind of ref it really was. See L<perlref>.
+
+=item Not a subroutine reference
+
+(F) Perl was trying to evaluate a reference to a code value (that is, a
+subroutine), but found a reference to something else instead. You can
+use the ref() function to find out what kind of ref it really was. See
+also L<perlref>.
+
+=item Not a subroutine reference in overload table
+
+(F) An attempt was made to specify an entry in an overloading table that
+doesn't somehow point to a valid subroutine. See L<overload>.
+
+=item Not enough arguments for %s
+
+(F) The function requires more arguments than you specified.
+
+=item Not enough format arguments
+
+(W syntax) A format specified more picture fields than the next line
+supplied. See L<perlform>.
+
+=item %s: not found
+
+(A) You've accidentally run your script through the Bourne shell instead
+of Perl. Check the #! line, or manually feed your script into Perl
+yourself.
+
+=item no UTC offset information; assuming local time is UTC
+
+(S) A warning peculiar to VMS. Perl was unable to find the local
+timezone offset, so it's assuming that local system time is equivalent
+to UTC. If it's not, define the logical name
+F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
+need to be added to UTC to get local time.
+
+=item Non-string passed as bitmask
+
+(W misc) A number has been passed as a bitmask argument to select().
+Use the vec() function to construct the file descriptor bitmasks for
+select. See L<perlfunc/select>
+
+=item Null filename used
+
+(F) You can't require the null filename, especially because on many
+machines that means the current directory! See L<perlfunc/require>.
+
+=item NULL OP IN RUN
+
+(P debugging) Some internal routine called run() with a null opcode
+pointer.
+
+=item Null picture in formline
+
+(F) The first argument to formline must be a valid format picture
+specification. It was found to be empty, which probably means you
+supplied it an uninitialized value. See L<perlform>.
+
+=item Null realloc
+
+(P) An attempt was made to realloc NULL.
+
+=item NULL regexp argument
+
+(P) The internal pattern matching routines blew it big time.
+
+=item NULL regexp parameter
+
+(P) The internal pattern matching routines are out of their gourd.
+
+=item Number too long
+
+(F) Perl limits the representation of decimal numbers in programs to
+about 250 characters. You've exceeded that length. Future
+versions of Perl are likely to eliminate this arbitrary limitation. In
+the meantime, try using scientific notation (e.g. "1e6" instead of
+"1_000_000").
+
+=item Octal number in vector unsupported
+
+(F) Numbers with a leading C<0> are not currently allowed in vectors.
+The octal number interpretation of such numbers may be supported in a
+future version.
+
+=item Octal number > 037777777777 non-portable
+
+(W portable) The octal number you specified is larger than 2**32-1
+(4294967295) and therefore non-portable between systems. See
+L<perlport> for more on portability concerns.
+
+See also L<perlport> for writing portable code.
+
+=item Odd number of arguments for overload::constant
+
+(W overload) The call to overload::constant contained an odd number of
+arguments. The arguments should come in pairs.
+
+=item Odd number of elements in anonymous hash
+
+(W misc) You specified an odd number of elements to initialize a hash,
+which is odd, because hashes come in key/value pairs.
+
+=item Odd number of elements in hash assignment
+
+(W misc) You specified an odd number of elements to initialize a hash,
+which is odd, because hashes come in key/value pairs.
+
+=item Offset outside string
+
+(F, W layer) You tried to do a read/write/send/recv/seek operation
+with an offset pointing outside the buffer. This is difficult to
+imagine. The sole exceptions to this are that zero padding will
+take place when going past the end of the string when either
+C<sysread()>ing a file, or when seeking past the end of a scalar opened
+for I/O (in anticipation of future reads and to imitate the behaviour
+with real files).
+
+=item %s() on unopened %s
+
+(W unopened) An I/O operation was attempted on a filehandle that was
+never initialized. You need to do an open(), a sysopen(), or a socket()
+call, or call a constructor from the FileHandle package.
+
+=item -%s on unopened filehandle %s
+
+(W unopened) You tried to invoke a file test operator on a filehandle
+that isn't open. Check your control flow. See also L<perlfunc/-X>.
+
+=item oops: oopsAV
+
+(S internal) An internal warning that the grammar is screwed up.
+
+=item oops: oopsHV
+
+(S internal) An internal warning that the grammar is screwed up.
+
+=item Opening dirhandle %s also as a file
+
+(W io deprecated) You used open() to associate a filehandle to
+a symbol (glob or scalar) that already holds a dirhandle.
+Although legal, this idiom might render your code confusing
+and is deprecated.
+
+=item Opening filehandle %s also as a directory
+
+(W io deprecated) You used opendir() to associate a dirhandle to
+a symbol (glob or scalar) that already holds a filehandle.
+Although legal, this idiom might render your code confusing
+and is deprecated.
+
+=item Operation "%s": no method found, %s
+
+(F) An attempt was made to perform an overloaded operation for which no
+handler was defined. While some handlers can be autogenerated in terms
+of other handlers, there is no default handler for any operation, unless
+C<fallback> overloading key is specified to be true. See L<overload>.
+
+=item Operator or semicolon missing before %s
+
+(S ambiguous) You used a variable or subroutine call where the parser
+was expecting an operator. The parser has assumed you really meant to
+use an operator, but this is highly likely to be incorrect. For
+example, if you say "*foo *foo" it will be interpreted as if you said
+"*foo * 'foo'".
+
+=item "our" variable %s redeclared
+
+(W misc) You seem to have already declared the same global once before
+in the current lexical scope.
+
+=item Out of memory!
+
+(X) The malloc() function returned 0, indicating there was insufficient
+remaining memory (or virtual memory) to satisfy the request. Perl has
+no option but to exit immediately.
+
+At least in Unix you may be able to get past this by increasing your
+process datasize limits: in csh/tcsh use C<limit> and
+C<limit datasize n> (where C<n> is the number of kilobytes) to check
+the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
+and C<ulimit -d n>, respectively.
+
+=item Out of memory during %s extend
+
+(X) An attempt was made to extend an array, a list, or a string beyond
+the largest possible memory allocation.
+
+=item Out of memory during "large" request for %s
+
+(F) The malloc() function returned 0, indicating there was insufficient
+remaining memory (or virtual memory) to satisfy the request. However,
+the request was judged large enough (compile-time default is 64K), so a
+possibility to shut down by trapping this error is granted.
+
+=item Out of memory during request for %s
+
+(X|F) The malloc() function returned 0, indicating there was
+insufficient remaining memory (or virtual memory) to satisfy the
+request.
+
+The request was judged to be small, so the possibility to trap it
+depends on the way perl was compiled. By default it is not trappable.
+However, if compiled for this, Perl may use the contents of C<$^M> as an
+emergency pool after die()ing with this message. In this case the error
+is trappable I<once>, and the error message will include the line and file
+where the failed request happened.
+
+=item Out of memory during ridiculously large request
+
+(F) You can't allocate more than 2^31+"small amount" bytes. This error
+is most likely to be caused by a typo in the Perl program. e.g.,
+C<$arr[time]> instead of C<$arr[$time]>.
+
+=item Out of memory for yacc stack
+
+(F) The yacc parser wanted to grow its stack so it could continue
+parsing, but realloc() wouldn't give it more memory, virtual or
+otherwise.
+
+=item '.' outside of string in pack
+
+(F) The argument to a '.' in your template tried to move the working
+position to before the start of the packed string being built.
+
+=item '@' outside of string in unpack
+
+(F) You had a template that specified an absolute position outside
+the string being unpacked. See L<perlfunc/pack>.
+
+=item '@' outside of string with malformed UTF-8 in unpack
+
+(F) You had a template that specified an absolute position outside
+the string being unpacked. The string being unpacked was also invalid
+UTF-8. See L<perlfunc/pack>.
+
+=item Overloaded dereference did not return a reference
+
+(F) An object with an overloaded dereference operator was dereferenced,
+but the overloaded operation did not return a reference. See
+L<overload>.
+
+=item Overloaded qr did not return a REGEXP
+
+(F) An object with a C<qr> overload was used as part of a match, but the
+overloaded operation didn't return a compiled regexp. See L<overload>.
+
+=item %s package attribute may clash with future reserved word: %s
+
+(W reserved) A lowercase attribute name was used that had a
+package-specific handler. That name might have a meaning to Perl itself
+some day, even though it doesn't yet. Perhaps you should use a
+mixed-case attribute name, instead. See L<attributes>.
+
+=item pack/unpack repeat count overflow
+
+(F) You can't specify a repeat count so large that it overflows your
+signed integers. See L<perlfunc/pack>.
+
+=item page overflow
+
+(W io) A single call to write() produced more lines than can fit on a
+page. See L<perlform>.
+
+=item panic: %s
+
+(P) An internal error.
+
+=item panic: attempt to call %s in %s
+
+(P) One of the file test operators entered a code branch that calls
+an ACL related-function, but that function is not available on this
+platform. Earlier checks mean that it should not be possible to
+enter this branch on this platform.
+
+=item panic: ck_grep
+
+(P) Failed an internal consistency check trying to compile a grep.
+
+=item panic: ck_split
+
+(P) Failed an internal consistency check trying to compile a split.
+
+=item panic: corrupt saved stack index
+
+(P) The savestack was requested to restore more localized values than
+there are in the savestack.
+
+=item panic: del_backref
+
+(P) Failed an internal consistency check while trying to reset a weak
+reference.
+
+=item panic: Devel::DProf inconsistent subroutine return
+
+(P) Devel::DProf called a subroutine that exited using goto(LABEL),
+last(LABEL) or next(LABEL). Leaving that way a subroutine called from
+an XSUB will lead very probably to a crash of the interpreter. This is
+a bug that will hopefully one day get fixed.
+
+=item panic: die %s
+
+(P) We popped the context stack to an eval context, and then discovered
+it wasn't an eval context.
+
+=item panic: do_subst
+
+(P) The internal pp_subst() routine was called with invalid operational
+data.
+
+=item panic: do_trans_%s
+
+(P) The internal do_trans routines were called with invalid operational
+data.
+
+=item panic: fold_constants JMPENV_PUSH returned %d
+
+(P) While attempting folding constants an exception other than an C<eval>
+failure was caught.
+
+=item panic: frexp
+
+(P) The library function frexp() failed, making printf("%f") impossible.
+
+=item panic: goto
+
+(P) We popped the context stack to a context with the specified label,
+and then discovered it wasn't a context we know how to do a goto in.
+
+=item panic: hfreeentries failed to free hash
+
+(P) The internal routine used to clear a hashes entries tried repeatedly,
+but each time something added more entries to the hash. Most likely the hash
+contains an object with a reference back to the hash and a destructor that
+adds a new object to the hash.
+
+=item panic: INTERPCASEMOD
+
+(P) The lexer got into a bad state at a case modifier.
+
+=item panic: INTERPCONCAT
+
+(P) The lexer got into a bad state parsing a string with brackets.
+
+=item panic: kid popen errno read
+
+(F) forked child returned an incomprehensible message about its errno.
+
+=item panic: last
+
+(P) We popped the context stack to a block context, and then discovered
+it wasn't a block context.
+
+=item panic: leave_scope clearsv
+
+(P) A writable lexical variable became read-only somehow within the
+scope.
+
+=item panic: leave_scope inconsistency
+
+(P) The savestack probably got out of sync. At least, there was an
+invalid enum on the top of it.
+
+=item panic: magic_killbackrefs
+
+(P) Failed an internal consistency check while trying to reset all weak
+references to an object.
+
+=item panic: malloc
+
+(P) Something requested a negative number of bytes of malloc.
+
+=item panic: memory wrap
+
+(P) Something tried to allocate more memory than possible.
+
+=item panic: pad_alloc
+
+(P) The compiler got confused about which scratch pad it was allocating
+and freeing temporaries and lexicals from.
+
+=item panic: pad_free curpad
+
+(P) The compiler got confused about which scratch pad it was allocating
+and freeing temporaries and lexicals from.
+
+=item panic: pad_free po
+
+(P) An invalid scratch pad offset was detected internally.
+
+=item panic: pad_reset curpad
+
+(P) The compiler got confused about which scratch pad it was allocating
+and freeing temporaries and lexicals from.
+
+=item panic: pad_sv po
+
+(P) An invalid scratch pad offset was detected internally.
+
+=item panic: pad_swipe curpad
+
+(P) The compiler got confused about which scratch pad it was allocating
+and freeing temporaries and lexicals from.
+
+=item panic: pad_swipe po
+
+(P) An invalid scratch pad offset was detected internally.
+
+=item panic: pp_iter
+
+(P) The foreach iterator got called in a non-loop context frame.
+
+=item panic: pp_match%s
+
+(P) The internal pp_match() routine was called with invalid operational
+data.
+
+=item panic: pp_split
+
+(P) Something terrible went wrong in setting up for the split.
+
+=item panic: realloc
+
+(P) Something requested a negative number of bytes of realloc.
+
+=item panic: restartop
+
+(P) Some internal routine requested a goto (or something like it), and
+didn't supply the destination.
+
+=item panic: return
+
+(P) We popped the context stack to a subroutine or eval context, and
+then discovered it wasn't a subroutine or eval context.
+
+=item panic: scan_num
+
+(P) scan_num() got called on something that wasn't a number.
+
+=item panic: sv_chop %s
+
+(P) The sv_chop() routine was passed a position that is not within the
+scalar's string buffer.
+
+=item panic: sv_insert
+
+(P) The sv_insert() routine was told to remove more string than there
+was string.
+
+=item panic: top_env
+
+(P) The compiler attempted to do a goto, or something weird like that.
+
+=item panic: unimplemented op %s (#%d) called
+
+(P) The compiler is screwed up and attempted to use an op that isn't permitted
+at run time.
+
+=item panic: utf16_to_utf8: odd bytelen
+
+(P) Something tried to call utf16_to_utf8 with an odd (as opposed
+to even) byte length.
+
+=item panic: utf16_to_utf8_reversed: odd bytelen
+
+(P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
+to even) byte length.
+
+=item panic: yylex
+
+(P) The lexer got into a bad state while processing a case modifier.
+
+=item Pattern subroutine nesting without pos change exceeded limit in regex; marked by <-- HERE in m/%s/
+
+(F) You used a pattern that uses too many nested subpattern calls without
+consuming any text. Restructure the pattern so text is consumed before the
+nesting limit is exceeded.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Parentheses missing around "%s" list
+
+(W parenthesis) You said something like
+
+ my $foo, $bar = @_;
+
+when you meant
+
+ my ($foo, $bar) = @_;
+
+Remember that "my", "our", "local" and "state" bind tighter than comma.
+
+=item C<-p> destination: %s
+
+(F) An error occurred during the implicit output invoked by the C<-p>
+command-line switch. (This output goes to STDOUT unless you've
+redirected it with select().)
+
+=item (perhaps you forgot to load "%s"?)
+
+(F) This is an educated guess made in conjunction with the message
+"Can't locate object method \"%s\" via package \"%s\"". It often means
+that a method requires a package that has not been loaded.
+
+=item Perl_my_%s() not available
+
+(F) Your platform has very uncommon byte-order and integer size,
+so it was not possible to set up some or all fixed-width byte-order
+conversion functions. This is only a problem when you're using the
+'<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
+
+=item Perl_pmflag() is deprecated, and will be removed from the XS API
+
+(D deprecated) XS code called the C function C<Perl_pmflag>. This was part of
+Perl's listed public API for extending or embedding the perl interpreter. It has
+now been removed from the public API, and will be removed in a future release,
+hence XS code should be re-written not to use it.
+
+=item Perl %s required--this is only version %s, stopped
+
+(F) The module in question uses features of a version of Perl more
+recent than the currently running version. How long has it been since
+you upgraded, anyway? See L<perlfunc/require>.
+
+=item PERL_SH_DIR too long
+
+(F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
+C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
+
+=item PERL_SIGNALS illegal: "%s"
+
+See L<perlrun/PERL_SIGNALS> for legal values.
+
+=item perl: warning: Setting locale failed.
+
+(S) The whole warning message will look something like:
+
+ perl: warning: Setting locale failed.
+ perl: warning: Please check that your locale settings:
+ LC_ALL = "En_US",
+ LANG = (unset)
+ are supported and installed on your system.
+ perl: warning: Falling back to the standard locale ("C").
+
+Exactly what were the failed locale settings varies. In the above the
+settings were that the LC_ALL was "En_US" and the LANG had no value.
+This error means that Perl detected that you and/or your operating
+system supplier and/or system administrator have set up the so-called
+locale system but Perl could not use those settings. This was not
+dead serious, fortunately: there is a "default locale" called "C" that
+Perl can and will use, the script will be run. Before you really fix
+the problem, however, you will get the same error message each time
+you run Perl. How to really fix the problem can be found in
+L<perllocale> section B<LOCALE PROBLEMS>.
+
+=item pid %x not a child
+
+(W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
+process which isn't a subprocess of the current process. While this is
+fine from VMS' perspective, it's probably not what you intended.
+
+=item 'P' must have an explicit size in unpack
+
+(F) The unpack format P must have an explicit size, not "*".
+
+=item POSIX class [:%s:] unknown in regex; marked by <-- HERE in m/%s/
+
+(F) The class in the character class [: :] syntax is unknown. The <-- HERE
+shows in the regular expression about where the problem was discovered.
+Note that the POSIX character classes do B<not> have the C<is> prefix
+the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
+not C<isprint>. See L<perlre>.
+
+=item POSIX getpgrp can't take an argument
+
+(F) Your system has POSIX getpgrp(), which takes no argument, unlike
+the BSD version, which takes a pid.
+
+=item POSIX syntax [%s] belongs inside character classes in regex; marked by <-- HERE in m/%s/
+
+(W regexp) The character class constructs [: :], [= =], and [. .] go
+I<inside> character classes, the [] are part of the construct, for example:
+/[012[:alpha:]345]/. Note that [= =] and [. .] are not currently
+implemented; they are simply placeholders for future extensions and will
+cause fatal errors. The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item POSIX syntax [. .] is reserved for future extensions in regex; marked by <-- HERE in m/%s/
+
+(F regexp) Within regular expression character classes ([]) the syntax
+beginning with "[." and ending with ".]" is reserved for future extensions.
+If you need to represent those character sequences inside a regular
+expression character class, just quote the square brackets with the
+backslash: "\[." and ".\]". The <-- HERE shows in the regular expression
+about where the problem was discovered. See L<perlre>.
+
+=item POSIX syntax [= =] is reserved for future extensions in regex; marked by <-- HERE in m/%s/
+
+(F) Within regular expression character classes ([]) the syntax beginning
+with "[=" and ending with "=]" is reserved for future extensions. If you
+need to represent those character sequences inside a regular expression
+character class, just quote the square brackets with the backslash: "\[="
+and "=\]". The <-- HERE shows in the regular expression about where the
+problem was discovered. See L<perlre>.
+
+=item Possible attempt to put comments in qw() list
+
+(W qw) qw() lists contain items separated by whitespace; as with literal
+strings, comment characters are not ignored, but are instead treated as
+literal data. (You may have used different delimiters than the
+parentheses shown here; braces are also frequently used.)
+
+You probably wrote something like this:
+
+ @list = qw(
+ a # a comment
+ b # another comment
+ );
+
+when you should have written this:
+
+ @list = qw(
+ a
+ b
+ );
+
+If you really want comments, build your list the
+old-fashioned way, with quotes and commas:
+
+ @list = (
+ 'a', # a comment
+ 'b', # another comment
+ );
+
+=item Possible attempt to separate words with commas
+
+(W qw) qw() lists contain items separated by whitespace; therefore
+commas aren't needed to separate the items. (You may have used
+different delimiters than the parentheses shown here; braces are also
+frequently used.)
+
+You probably wrote something like this:
+
+ qw! a, b, c !;
+
+which puts literal commas into some of the list items. Write it without
+commas if you don't want them to appear in your data:
+
+ qw! a b c !;
+
+=item Possible memory corruption: %s overflowed 3rd argument
+
+(F) An ioctl() or fcntl() returned more than Perl was bargaining for.
+Perl guesses a reasonable buffer size, but puts a sentinel byte at the
+end of the buffer just in case. This sentinel byte got clobbered, and
+Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
+
+=item Possible precedence problem on bitwise %c operator
+
+(W precedence) Your program uses a bitwise logical operator in conjunction
+with a numeric comparison operator, like this :
+
+ if ($x & $y == 0) { ... }
+
+This expression is actually equivalent to C<$x & ($y == 0)>, due to the
+higher precedence of C<==>. This is probably not what you want. (If you
+really meant to write this, disable the warning, or, better, put the
+parentheses explicitly and write C<$x & ($y == 0)>).
+
+=item Possible unintended interpolation of %s in string
+
+(W ambiguous) You said something like `@foo' in a double-quoted string
+but there was no array C<@foo> in scope at the time. If you wanted a
+literal @foo, then write it as \@foo; otherwise find out what happened
+to the array you apparently lost track of.
+
+=item Possible unintended interpolation of $\ in regex
+
+(W ambiguous) You said something like C<m/$\/> in a regex.
+The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
+record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
+followed by the word 'bar'.
+
+If this is what you intended then you can silence the warning by using
+C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
+
+If instead you intended to match the word 'foo' at the end of the line
+followed by whitespace and the word 'bar' on the next line then you can use
+C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
+
+=item Precedence problem: open %s should be open(%s)
+
+(S precedence) The old irregular construct
+
+ open FOO || die;
+
+is now misinterpreted as
+
+ open(FOO || die);
+
+because of the strict regularization of Perl 5's grammar into unary and
+list operators. (The old open was a little of both.) You must put
+parentheses around the filehandle, or use the new "or" operator instead
+of "||".
+
+=item Premature end of script headers
+
+See Server error.
+
+=item printf() on closed filehandle %s
+
+(W closed) The filehandle you're writing to got itself closed sometime
+before now. Check your control flow.
+
+=item print() on closed filehandle %s
+
+(W closed) The filehandle you're printing on got itself closed sometime
+before now. Check your control flow.
+
+=item Process terminated by SIG%s
+
+(W) This is a standard message issued by OS/2 applications, while *nix
+applications die in silence. It is considered a feature of the OS/2
+port. One can easily disable this by appropriate sighandlers, see
+L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
+in L<perlos2>.
+
+=item Prototype after '%c' for %s : %s
+
+(W illegalproto) A character follows % or @ in a prototype. This is useless,
+since % and @ gobble the rest of the subroutine arguments.
+
+=item Prototype mismatch: %s vs %s
+
+(S prototype) The subroutine being declared or defined had previously been
+declared or defined with a different function prototype.
+
+=item Prototype not terminated
+
+(F) You've omitted the closing parenthesis in a function prototype
+definition.
+
+=item Quantifier follows nothing in regex; marked by <-- HERE in m/%s/
+
+(F) You started a regular expression with a quantifier. Backslash it if you
+meant it literally. The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item Quantifier in {,} bigger than %d in regex; marked by <-- HERE in m/%s/
+
+(F) There is currently a limit to the size of the min and max values of the
+{min,max} construct. The <-- HERE shows in the regular expression about where
+the problem was discovered. See L<perlre>.
+
+=item Quantifier unexpected on zero-length expression; marked by <-- HERE in m/%s/
+
+(W regexp) You applied a regular expression quantifier in a place where
+it makes no sense, such as on a zero-width assertion. Try putting the
+quantifier inside the assertion instead. For example, the way to match
+"abc" provided that it is followed by three repetitions of "xyz" is
+C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Range iterator outside integer range
+
+(F) One (or both) of the numeric arguments to the range operator ".."
+are outside the range which can be represented by integers internally.
+One possible workaround is to force Perl to use magical string increment
+by prepending "0" to your numbers.
+
+=item readdir() attempted on invalid dirhandle %s
+
+(W io) The dirhandle you're reading from is either closed or not really
+a dirhandle. Check your control flow.
+
+=item readline() on closed filehandle %s
+
+(W closed) The filehandle you're reading from got itself closed sometime
+before now. Check your control flow.
+
+=item read() on closed filehandle %s
+
+(W closed) You tried to read from a closed filehandle.
+
+=item read() on unopened filehandle %s
+
+(W unopened) You tried to read from a filehandle that was never opened.
+
+=item Reallocation too large: %lx
+
+(F) You can't allocate more than 64K on an MS-DOS machine.
+
+=item realloc() of freed memory ignored
+
+(S malloc) An internal routine called realloc() on something that had
+already been freed.
+
+=item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
+
+(F debugging) You can't use the B<-D> option unless the code to produce
+the desired output is compiled into Perl, which entails some overhead,
+which is why it's currently left out of your copy.
+
+=item Recursive inheritance detected in package '%s'
+
+(F) While calculating the method resolution order (MRO) of a package, Perl
+believes it found an infinite loop in the C<@ISA> hierarchy. This is a
+crude check that bails out after 100 levels of C<@ISA> depth.
+
+=item Recursive inheritance detected while looking for method %s
+
+(F) More than 100 levels of inheritance were encountered while invoking
+a method. Probably indicates an unintended loop in your inheritance
+hierarchy.
+
+=item Reference found where even-sized list expected
+
+(W misc) You gave a single reference where Perl was expecting a list
+with an even number of elements (for assignment to a hash). This usually
+means that you used the anon hash constructor when you meant to use
+parens. In any case, a hash requires key/value B<pairs>.
+
+ %hash = { one => 1, two => 2, }; # WRONG
+ %hash = [ qw/ an anon array / ]; # WRONG
+ %hash = ( one => 1, two => 2, ); # right
+ %hash = qw( one 1 two 2 ); # also fine
+
+=item Reference is already weak
+
+(W misc) You have attempted to weaken a reference that is already weak.
+Doing so has no effect.
+
+=item Reference miscount in sv_replace()
+
+(W internal) The internal sv_replace() function was handed a new SV with
+a reference count of other than 1.
+
+=item Reference to invalid group 0
+
+(F) You used C<\g0> or similar in a regular expression. You may refer to
+capturing parentheses only with strictly positive integers (normal
+backreferences) or with strictly negative integers (relative
+backreferences), but using 0 does not make sense.
+
+=item Reference to nonexistent group in regex; marked by <-- HERE in m/%s/
+
+(F) You used something like C<\7> in your regular expression, but there are
+not at least seven sets of capturing parentheses in the expression. If you
+wanted to have the character with value 7 inserted into the regular expression,
+prepend a zero to make the number at least two digits: C<\07>
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Reference to nonexistent or unclosed group in regex; marked by <-- HERE in m/%s/
+
+(F) You used something like C<\g{-7}> in your regular expression, but there are
+not at least seven sets of closed capturing parentheses in the expression before
+where the C<\g{-7}> was located.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item Reference to nonexistent named group in regex; marked by <-- HERE in m/%s/
+
+(F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
+expression, but there is no corresponding named capturing parentheses such
+as C<(?'NAME'...)> or C<(?<NAME>...). Check if the name has been spelled
+correctly both in the backreference and the declaration.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item (?(DEFINE)....) does not allow branches in regex; marked by <-- HERE in m/%s/
+
+(F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
+most likely cause of this error is that you left out a parenthesis inside
+of the C<....> part.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
+=item regexp memory corruption
+
+(P) The regular expression engine got confused by what the regular
+expression compiler gave it.
+
+=item Regexp out of space
+
+(P) A "can't happen" error, because safemalloc() should have caught it
+earlier.
+
+=item Repeated format line will never terminate (~~ and @# incompatible)
+
+(F) Your format contains the ~~ repeat-until-blank sequence and a
+numeric field that will never go blank so that the repetition never
+terminates. You might use ^# instead. See L<perlform>.
+
+=item Replacement list is longer than search list
+
+(W misc) You have used a replacement list that is longer than the
+search list. So the additional elements in the replacement list
+are meaningless.
+
+=item Reversed %s= operator
+
+(W syntax) You wrote your assignment operator backwards. The = must
+always comes last, to avoid ambiguity with subsequent unary operators.
+
+=item rewinddir() attempted on invalid dirhandle %s
+
+(W io) The dirhandle you tried to do a rewinddir() on is either closed or not
+really a dirhandle. Check your control flow.
+
+=item Scalars leaked: %d
+
+(P) Something went wrong in Perl's internal bookkeeping of scalars:
+not all scalar variables were deallocated by the time Perl exited.
+What this usually indicates is a memory leak, which is of course bad,
+especially if the Perl program is intended to be long-running.
+
+=item Scalar value @%s[%s] better written as $%s[%s]
+
+(W syntax) You've used an array slice (indicated by @) to select a
+single element of an array. Generally it's better to ask for a scalar
+value (indicated by $). The difference is that C<$foo[&bar]> always
+behaves like a scalar, both when assigning to it and when evaluating its
+argument, while C<@foo[&bar]> behaves like a list when you assign to it,
+and provides a list context to its subscript, which can do weird things
+if you're expecting only one subscript.
+
+On the other hand, if you were actually hoping to treat the array
+element as a list, you need to look into how references work, because
+Perl will not magically convert between scalars and lists for you. See
+L<perlref>.
+
+=item Scalar value @%s{%s} better written as $%s{%s}
+
+(W syntax) You've used a hash slice (indicated by @) to select a single
+element of a hash. Generally it's better to ask for a scalar value
+(indicated by $). The difference is that C<$foo{&bar}> always behaves
+like a scalar, both when assigning to it and when evaluating its
+argument, while C<@foo{&bar}> behaves like a list when you assign to it,
+and provides a list context to its subscript, which can do weird things
+if you're expecting only one subscript.
+
+On the other hand, if you were actually hoping to treat the hash element
+as a list, you need to look into how references work, because Perl will
+not magically convert between scalars and lists for you. See
+L<perlref>.
+
+=item Search pattern not terminated
+
+(F) The lexer couldn't find the final delimiter of a // or m{}
+construct. Remember that bracketing delimiters count nesting level.
+Missing the leading C<$> from a variable C<$m> may cause this error.
+
+Note that since Perl 5.9.0 a // can also be the I<defined-or>
+construct, not just the empty search pattern. Therefore code written
+in Perl 5.9.0 or later that uses the // as the I<defined-or> can be
+misparsed by pre-5.9.0 Perls as a non-terminated search pattern.
+
+=item Search pattern not terminated or ternary operator parsed as search pattern
+
+(F) The lexer couldn't find the final delimiter of a C<?PATTERN?>
+construct.
+
+The question mark is also used as part of the ternary operator (as in
+C<foo ? 0 : 1>) leading to some ambiguous constructions being wrongly
+parsed. One way to disambiguate the parsing is to put parentheses around
+the conditional expression, i.e. C<(foo) ? 0 : 1>.
+
+=item %sseek() on unopened filehandle
+
+(W unopened) You tried to use the seek() or sysseek() function on a
+filehandle that was either never opened or has since been closed.
+
+=item seekdir() attempted on invalid dirhandle %s
+
+(W io) The dirhandle you are doing a seekdir() on is either closed or not
+really a dirhandle. Check your control flow.
+
+=item select not implemented
+
+(F) This machine doesn't implement the select() system call.
+
+=item Self-ties of arrays and hashes are not supported
+
+(F) Self-ties are of arrays and hashes are not supported in
+the current implementation.
+
+=item Semicolon seems to be missing
+
+(W semicolon) A nearby syntax error was probably caused by a missing
+semicolon, or possibly some other missing operator, such as a comma.
+
+=item semi-panic: attempt to dup freed string
+
+(S internal) The internal newSVsv() routine was called to duplicate a
+scalar that had previously been marked as free.
+
+=item sem%s not implemented
+
+(F) You don't have System V semaphore IPC on your system.
+
+=item send() on closed socket %s
+
+(W closed) The socket you're sending to got itself closed sometime
+before now. Check your control flow.
+
+=item Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
+
+(F) A regular expression ended with an incomplete extension (?. The <-- HERE
+shows in the regular expression about where the problem was discovered. See
+L<perlre>.
+
+=item Sequence (?%s...) not implemented in regex; marked by <-- HERE in m/%s/
+
+(F) A proposed regular expression extension has the character reserved but
+has not yet been written. The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item Sequence (?%s...) not recognized in regex; marked by <-- HERE in m/%s/
+
+(F) You used a regular expression extension that doesn't make sense. The
+<-- HERE shows in the regular expression about where the problem was
+discovered. See L<perlre>.
+
+=item Sequence \\%s... not terminated in regex; marked by <-- HERE in m/%s/
+
+(F) The regular expression expects a mandatory argument following the escape
+sequence and this has been omitted or incorrectly written.
+
+=item Sequence (?#... not terminated in regex; marked by <-- HERE in m/%s/
+
+(F) A regular expression comment must be terminated by a closing
+parenthesis. Embedded parentheses aren't allowed. The <-- HERE shows in
+the regular expression about where the problem was discovered. See
+L<perlre>.
+
+=item Sequence (?{...}) not terminated or not {}-balanced in regex; marked by <-- HERE in m/%s/
+
+(F) If the contents of a (?{...}) clause contains braces, they must balance
+for Perl to properly detect the end of the clause. The <-- HERE shows in
+the regular expression about where the problem was discovered. See
+L<perlre>.
+
+=item 500 Server error
+
+See Server error.
+
+=item Server error
+
+This is the error message generally seen in a browser window when trying
+to run a CGI program (including SSI) over the web. The actual error text
+varies widely from server to server. The most frequently-seen variants
+are "500 Server error", "Method (something) not permitted", "Document
+contains no data", "Premature end of script headers", and "Did not
+produce a valid header".
+
+B<This is a CGI error, not a Perl error>.
+
+You need to make sure your script is executable, is accessible by the
+user CGI is running the script under (which is probably not the user
+account you tested it under), does not rely on any environment variables
+(like PATH) from the user it isn't running under, and isn't in a
+location where the CGI server can't find it, basically, more or less.
+Please see the following for more information:
+
+ http://www.perl.org/CGI_MetaFAQ.html
+ http://www.htmlhelp.org/faq/cgifaq.html
+ http://www.w3.org/Security/Faq/
+
+You should also look at L<perlfaq9>.
+
+=item setegid() not implemented
+
+(F) You tried to assign to C<$)>, and your operating system doesn't
+support the setegid() system call (or equivalent), or at least Configure
+didn't think so.
+
+=item seteuid() not implemented
+
+(F) You tried to assign to C<< $> >>, and your operating system doesn't
+support the seteuid() system call (or equivalent), or at least Configure
+didn't think so.
+
+=item setpgrp can't take arguments
+
+(F) Your system has the setpgrp() from BSD 4.2, which takes no
+arguments, unlike POSIX setpgid(), which takes a process ID and process
+group ID.
+
+=item setrgid() not implemented
+
+(F) You tried to assign to C<$(>, and your operating system doesn't
+support the setrgid() system call (or equivalent), or at least Configure
+didn't think so.
+
+=item setruid() not implemented
+
+(F) You tried to assign to C<$<>, and your operating system doesn't
+support the setruid() system call (or equivalent), or at least Configure
+didn't think so.
+
+=item setsockopt() on closed socket %s
+
+(W closed) You tried to set a socket option on a closed socket. Did you
+forget to check the return value of your socket() call? See
+L<perlfunc/setsockopt>.
+
+=item Setuid/gid script is writable by world
+
+(F) The setuid emulator won't run a script that is writable by the
+world, because the world might have written on it already.
+
+=item Setuid script not plain file
+
+(F) The setuid emulator won't run a script that isn't read from a file,
+but from a socket, a pipe or another device.
+
+=item shm%s not implemented
+
+(F) You don't have System V shared memory IPC on your system.
+
+=item !=~ should be !~
+
+(W syntax) The non-matching operator is !~, not !=~. !=~ will be
+interpreted as the != (numeric not equal) and ~ (1's complement)
+operators: probably not what you intended.
+
+=item <> should be quotes
+
+(F) You wrote C<< require <file> >> when you should have written
+C<require 'file'>.
+
+=item /%s/ should probably be written as "%s"
+
+(W syntax) You have used a pattern where Perl expected to find a string,
+as in the first argument to C<join>. Perl will treat the true or false
+result of matching the pattern against $_ as the string, which is
+probably not what you had in mind.
+
+=item shutdown() on closed socket %s
+
+(W closed) You tried to do a shutdown on a closed socket. Seems a bit
+superfluous.
+
+=item SIG%s handler "%s" not defined
+
+(W signal) The signal handler named in %SIG doesn't, in fact, exist.
+Perhaps you put it into the wrong package?
+
+=item Smart matching a non-overloaded object breaks encapsulation
+
+(F) You should not use the C<~~> operator on an object that does not
+overload it: Perl refuses to use the object's underlying structure for
+the smart match.
+
+=item sort is now a reserved word
+
+(F) An ancient error message that almost nobody ever runs into anymore.
+But before sort was a keyword, people sometimes used it as a filehandle.
+
+=item Sort subroutine didn't return single value
+
+(F) A sort comparison subroutine may not return a list value with more
+or less than one element. See L<perlfunc/sort>.
+
+=item splice() offset past end of array
+
+(W misc) You attempted to specify an offset that was past the end of
+the array passed to splice(). Splicing will instead commence at the end
+of the array, rather than past it. If this isn't what you want, try
+explicitly pre-extending the array by assigning $#array = $offset. See
+L<perlfunc/splice>.
+
+=item Split loop
+
+(P) The split was looping infinitely. (Obviously, a split shouldn't
+iterate more times than there are characters of input, which is what
+happened.) See L<perlfunc/split>.
+
+=item Statement unlikely to be reached
+
+(W exec) You did an exec() with some statement after it other than a
+die(). This is almost always an error, because exec() never returns
+unless there was a failure. You probably wanted to use system()
+instead, which does return. To suppress this warning, put the exec() in
+a block by itself.
+
+=item stat() on unopened filehandle %s
+
+(W unopened) You tried to use the stat() function on a filehandle that
+was either never opened or has since been closed.
+
+=item Stub found while resolving method "%s" overloading "%s" in package "%s"
+
+(P) Overloading resolution over @ISA tree may be broken by importation
+stubs. Stubs should never be implicitly created, but explicit calls to
+C<can> may break this.
+
+=item Subroutine %s redefined
+
+(W redefine) You redefined a subroutine. To suppress this warning, say
+
+ {
+ no warnings 'redefine';
+ eval "sub name { ... }";
+ }
+
+=item Substitution loop
+
+(P) The substitution was looping infinitely. (Obviously, a substitution
+shouldn't iterate more times than there are characters of input, which
+is what happened.) See the discussion of substitution in
+L<perlop/"Regexp Quote-Like Operators">.
+
+=item Substitution pattern not terminated
+
+(F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
+construct. Remember that bracketing delimiters count nesting level.
+Missing the leading C<$> from variable C<$s> may cause this error.
+
+=item Substitution replacement not terminated
+
+(F) The lexer couldn't find the final delimiter of an s/// or s{}{}
+construct. Remember that bracketing delimiters count nesting level.
+Missing the leading C<$> from variable C<$s> may cause this error.
+
+=item substr outside of string
+
+(W substr),(F) You tried to reference a substr() that pointed outside of
+a string. That is, the absolute value of the offset was larger than the
+length of the string. See L<perlfunc/substr>. This warning is fatal if
+substr is used in an lvalue context (as the left hand side of an
+assignment or as a subroutine argument for example).
+
+=item sv_upgrade from type %d down to type %d
+
+(P) Perl tried to force the upgrade an SV to a type which was actually
+inferior to its current type.
+
+=item Switch (?(condition)... contains too many branches in regex; marked by <-- HERE in m/%s/
+
+(F) A (?(condition)if-clause|else-clause) construct can have at most two
+branches (the if-clause and the else-clause). If you want one or both to
+contain alternation, such as using C<this|that|other>, enclose it in
+clustering parentheses:
+
+ (?(condition)(?:this|that|other)|else-clause)
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered. See L<perlre>.
+
+=item Switch condition not recognized in regex; marked by <-- HERE in m/%s/
+
+(F) If the argument to the (?(...)if-clause|else-clause) construct is a
+number, it can be only a number. The <-- HERE shows in the regular expression
+about where the problem was discovered. See L<perlre>.
+
+=item switching effective %s is not implemented
+
+(F) While under the C<use filetest> pragma, we cannot switch the real
+and effective uids or gids.
+
+=item %s syntax
+
+(F) The final summary message when a C<perl -c> succeeds.
+
+=item syntax error
+
+(F) Probably means you had a syntax error. Common reasons include:
+
+ A keyword is misspelled.
+ A semicolon is missing.
+ A comma is missing.
+ An opening or closing parenthesis is missing.
+ An opening or closing brace is missing.
+ A closing quote is missing.
+
+Often there will be another error message associated with the syntax
+error giving more information. (Sometimes it helps to turn on B<-w>.)
+The error message itself often tells you where it was in the line when
+it decided to give up. Sometimes the actual error is several tokens
+before this, because Perl is good at understanding random input.
+Occasionally the line number may be misleading, and once in a blue moon
+the only way to figure out what's triggering the error is to call
+C<perl -c> repeatedly, chopping away half the program each time to see
+if the error went away. Sort of the cybernetic version of S<20
+questions>.
+
+=item syntax error at line %d: `%s' unexpected
+
+(A) You've accidentally run your script through the Bourne shell instead
+of Perl. Check the #! line, or manually feed your script into Perl
+yourself.
+
+=item syntax error in file %s at line %d, next 2 tokens "%s"
+
+(F) This error is likely to occur if you run a perl5 script through
+a perl4 interpreter, especially if the next 2 tokens are "use strict"
+or "my $var" or "our $var".
+
+=item sysread() on closed filehandle %s
+
+(W closed) You tried to read from a closed filehandle.
+
+=item sysread() on unopened filehandle %s
+
+(W unopened) You tried to read from a filehandle that was never opened.
+
+=item System V %s is not implemented on this machine
+
+(F) You tried to do something with a function beginning with "sem",
+"shm", or "msg" but that System V IPC is not implemented in your
+machine. In some machines the functionality can exist but be
+unconfigured. Consult your system support.
+
+=item syswrite() on closed filehandle %s
+
+(W closed) The filehandle you're writing to got itself closed sometime
+before now. Check your control flow.
+
+=item C<-T> and C<-B> not implemented on filehandles
+
+(F) Perl can't peek at the stdio buffer of filehandles when it doesn't
+know about your kind of stdio. You'll have to use a filename instead.
+
+=item Target of goto is too deeply nested
+
+(F) You tried to use C<goto> to reach a label that was too deeply nested
+for Perl to reach. Perl is doing you a favor by refusing.
+
+=item tell() on unopened filehandle
+
+(W unopened) You tried to use the tell() function on a filehandle that
+was either never opened or has since been closed.
+
+=item telldir() attempted on invalid dirhandle %s
+
+(W io) The dirhandle you tried to telldir() is either closed or not really
+a dirhandle. Check your control flow.
+
+=item That use of $[ is unsupported
+
+(F) Assignment to C<$[> is now strictly circumscribed, and interpreted
+as a compiler directive. You may say only one of
+
+ $[ = 0;
+ $[ = 1;
+ ...
+ local $[ = 0;
+ local $[ = 1;
+ ...
+
+This is to prevent the problem of one module changing the array base out
+from under another module inadvertently. See L<perlvar/$[>.
+
+=item The crypt() function is unimplemented due to excessive paranoia
+
+(F) Configure couldn't find the crypt() function on your machine,
+probably because your vendor didn't supply it, probably because they
+think the U.S. Government thinks it's a secret, or at least that they
+will continue to pretend that it is. And if you quote me on that, I
+will deny it.
+
+=item The %s function is unimplemented
+
+The function indicated isn't implemented on this architecture, according
+to the probings of Configure.
+
+=item The stat preceding %s wasn't an lstat
+
+(F) It makes no sense to test the current stat buffer for symbolic
+linkhood if the last stat that wrote to the stat buffer already went
+past the symlink to get to the real file. Use an actual filename
+instead.
+
+=item The 'unique' attribute may only be applied to 'our' variables
+
+(F) This attribute was never supported on C<my> or C<sub> declarations.
+
+=item This Perl can't reset CRTL environ elements (%s)
+
+=item This Perl can't set CRTL environ elements (%s=%s)
+
+(W internal) Warnings peculiar to VMS. You tried to change or delete an
+element of the CRTL's internal environ array, but your copy of Perl
+wasn't built with a CRTL that contained the setenv() function. You'll
+need to rebuild Perl with a CRTL that does, or redefine
+F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
+target of the change to
+%ENV which produced the warning.
+
+=item thread failed to start: %s
+
+(W threads)(S) The entry point function of threads->create() failed for some reason.
+
+=item times not implemented
+
+(F) Your version of the C library apparently doesn't do times(). I
+suspect you're not running on Unix.
+
+=item "-T" is on the #! line, it must also be used on the command line
+
+(X) The #! line (or local equivalent) in a Perl script contains the
+B<-T> option (or the B<-t> option), but Perl was not invoked with B<-T> in its command line.
+This is an error because, by the time Perl discovers a B<-T> in a
+script, it's too late to properly taint everything from the environment.
+So Perl gives up.
+
+If the Perl script is being executed as a command using the #!
+mechanism (or its local equivalent), this error can usually be fixed by
+editing the #! line so that the B<-%c> option is a part of Perl's first
+argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
+
+If the Perl script is being executed as C<perl scriptname>, then the
+B<-%c> option must appear on the command line: C<perl -%c scriptname>.
+
+=item To%s: illegal mapping '%s'
+
+(F) You tried to define a customized To-mapping for lc(), lcfirst,
+uc(), or ucfirst() (or their string-inlined versions), but you
+specified an illegal mapping.
+See L<perlunicode/"User-Defined Character Properties">.
+
+=item Too deeply nested ()-groups
+
+(F) Your template contains ()-groups with a ridiculously deep nesting level.
+
+=item Too few args to syscall
+
+(F) There has to be at least one argument to syscall() to specify the
+system call to call, silly dilly.
+
+=item Too late for "-%s" option
+
+(X) The #! line (or local equivalent) in a Perl script contains the
+B<-M>, B<-m> or B<-C> option.
+
+In the case of B<-M> and B<-m>, this is an error because those options are
+not intended for use inside scripts. Use the C<use> pragma instead.
+
+The B<-C> option only works if it is specified on the command line as well
+(with the same sequence of letters or numbers following). Either specify
+this option on the command line, or, if your system supports it, make your
+script executable and run it directly instead of passing it to perl.
+
+=item Too late to run %s block
+
+(W void) A CHECK or INIT block is being defined during run time proper,
+when the opportunity to run them has already passed. Perhaps you are
+loading a file with C<require> or C<do> when you should be using C<use>
+instead. Or perhaps you should put the C<require> or C<do> inside a
+BEGIN block.
+
+=item Too many args to syscall
+
+(F) Perl supports a maximum of only 14 args to syscall().
+
+=item Too many arguments for %s
+
+(F) The function requires fewer arguments than you specified.
+
+=item Too many )'s
+
+(A) You've accidentally run your script through B<csh> instead of Perl.
+Check the #! line, or manually feed your script into Perl yourself.
+
+=item Too many ('s
+
+(A) You've accidentally run your script through B<csh> instead of Perl.
+Check the #! line, or manually feed your script into Perl yourself.
+
+=item Trailing \ in regex m/%s/
+
+(F) The regular expression ends with an unbackslashed backslash.
+Backslash it. See L<perlre>.
+
+=item Transliteration pattern not terminated
+
+(F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
+or y/// or y[][] construct. Missing the leading C<$> from variables
+C<$tr> or C<$y> may cause this error.
+
+=item Transliteration replacement not terminated
+
+(F) The lexer couldn't find the final delimiter of a tr///, tr[][],
+y/// or y[][] construct.
+
+=item '%s' trapped by operation mask
+
+(F) You tried to use an operator from a Safe compartment in which it's
+disallowed. See L<Safe>.
+
+=item truncate not implemented
+
+(F) Your machine doesn't implement a file truncation mechanism that
+Configure knows about.
+
+=item Type of arg %d to %s must be %s (not %s)
+
+(F) This function requires the argument in that position to be of a
+certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
+%NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
+{EXPR} forms as an explicit dereference. See L<perlref>.
+
+=item umask not implemented
+
+(F) Your machine doesn't implement the umask function and you tried to
+use it to restrict permissions for yourself (EXPR & 0700).
+
+=item Unable to create sub named "%s"
+
+(F) You attempted to create or access a subroutine with an illegal name.
+
+=item Unbalanced context: %d more PUSHes than POPs
+
+(W internal) The exit code detected an internal inconsistency in how
+many execution contexts were entered and left.
+
+=item Unbalanced saves: %d more saves than restores
+
+(W internal) The exit code detected an internal inconsistency in how
+many values were temporarily localized.
+
+=item Unbalanced scopes: %d more ENTERs than LEAVEs
+
+(W internal) The exit code detected an internal inconsistency in how
+many blocks were entered and left.
+
+=item Unbalanced tmps: %d more allocs than frees
+
+(W internal) The exit code detected an internal inconsistency in how
+many mortal scalars were allocated and freed.
+
+=item Undefined format "%s" called
+
+(F) The format indicated doesn't seem to exist. Perhaps it's really in
+another package? See L<perlform>.
+
+=item Undefined sort subroutine "%s" called
+
+(F) The sort comparison routine specified doesn't seem to exist.
+Perhaps it's in a different package? See L<perlfunc/sort>.
+
+=item Undefined subroutine &%s called
+
+(F) The subroutine indicated hasn't been defined, or if it was, it has
+since been undefined.
+
+=item Undefined subroutine called
+
+(F) The anonymous subroutine you're trying to call hasn't been defined,
+or if it was, it has since been undefined.
+
+=item Undefined subroutine in sort
+
+(F) The sort comparison routine specified is declared but doesn't seem
+to have been defined yet. See L<perlfunc/sort>.
+
+=item Undefined top format "%s" called
+
+(F) The format indicated doesn't seem to exist. Perhaps it's really in
+another package? See L<perlform>.
+
+=item Undefined value assigned to typeglob
+
+(W misc) An undefined value was assigned to a typeglob, a la
+C<*foo = undef>. This does nothing. It's possible that you really mean
+C<undef *foo>.
+
+=item %s: Undefined variable
+
+(A) You've accidentally run your script through B<csh> instead of Perl.
+Check the #! line, or manually feed your script into Perl yourself.
+
+=item unexec of %s into %s failed!
+
+(F) The unexec() routine failed for some reason. See your local FSF
+representative, who probably put it there in the first place.
+
+=item Unicode non-character %s is illegal for interchange
+
+(W utf8) Certain codepoints, such as U+FFFE and U+FFFF, are defined by the
+Unicode standard to be non-characters. Those are legal codepoints, but are
+reserved for internal use; so, applications shouldn't attempt to exchange
+them. In some cases, this message is also given if you use a codepoint that
+isn't in Unicode--that is it is above the legal maximum of U+10FFFF. These
+aren't legal at all in Unicode, so they are illegal for interchange, but can be
+used internally in a Perl program. If you know what you are doing you can turn
+off this warning by C<no warnings 'utf8';>.
+
+=item Unknown BYTEORDER
+
+(F) There are no byte-swapping functions for a machine with this byte
+order.
+
+=item Unknown open() mode '%s'
+
+(F) The second argument of 3-argument open() is not among the list
+of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
+C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
+
+=item Unknown PerlIO layer "%s"
+
+(W layer) An attempt was made to push an unknown layer onto the Perl I/O
+system. (Layers take care of transforming data between external and
+internal representations.) Note that some layers, such as C<mmap>,
+are not supported in all environments. If your program didn't
+explicitly request the failing operation, it may be the result of the
+value of the environment variable PERLIO.
+
+=item Unknown process %x sent message to prime_env_iter: %s
+
+(P) An error peculiar to VMS. Perl was reading values for %ENV before
+iterating over it, and someone else stuck a message in the stream of
+data Perl expected. Someone's very confused, or perhaps trying to
+subvert Perl's population of %ENV for nefarious purposes.
+
+=item Unknown "re" subpragma '%s' (known ones are: %s)
+
+You tried to use an unknown subpragma of the "re" pragma.
+
+=item Unknown switch condition (?(%.2s in regex; marked by <-- HERE in m/%s/
+
+(F) The condition part of a (?(condition)if-clause|else-clause) construct
+is not known. The condition may be lookahead or lookbehind (the condition
+is true if the lookahead or lookbehind is true), a (?{...}) construct (the
+condition is true if the code evaluates to a true value), or a number (the
+condition is true if the set of capturing parentheses named by the number
+matched).
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered. See L<perlre>.
+
+=item Unknown Unicode option letter '%c'
+
+You specified an unknown Unicode option. See L<perlrun> documentation
+of the C<-C> switch for the list of known options.
+
+=item Unknown Unicode option value %x
+
+You specified an unknown Unicode option. See L<perlrun> documentation
+of the C<-C> switch for the list of known options.
+
+=item Unknown warnings category '%s'
+
+(F) An error issued by the C<warnings> pragma. You specified a warnings
+category that is unknown to perl at this point.
+
+Note that if you want to enable a warnings category registered by a module
+(e.g. C<use warnings 'File::Find'>), you must have imported this module
+
+=item Unknown verb pattern '%s' in regex; marked by <-- HERE in m/%s/
+
+(F) You either made a typo or have incorrectly put a C<*> quantifier
+after an open brace in your pattern. Check the pattern and review
+L<perlre> for details on legal verb patterns.
+
+first.
+
+=item unmatched [ in regex; marked by <-- HERE in m/%s/
+
+(F) The brackets around a character class must match. If you wish to
+include a closing bracket in a character class, backslash it or put it
+first. The <-- HERE shows in the regular expression about where the problem
+was discovered. See L<perlre>.
+
+=item unmatched ( in regex; marked by <-- HERE in m/%s/
+
+(F) Unbackslashed parentheses must always be balanced in regular
+expressions. If you're a vi user, the % key is valuable for finding the
+matching parenthesis. The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item Unmatched right %s bracket
+
+(F) The lexer counted more closing curly or square brackets than opening
+ones, so you're probably missing a matching opening bracket. As a
+general rule, you'll find the missing one (so to speak) near the place
+you were last editing.
+
+=item Unquoted string "%s" may clash with future reserved word
+
+(W reserved) You used a bareword that might someday be claimed as a
+reserved word. It's best to put such a word in quotes, or capitalize it
+somehow, or insert an underbar into it. You might also declare it as a
+subroutine.
+
+=item Unrecognized character %s; marked by <-- HERE after %s near column %d
+
+(F) The Perl parser has no idea what to do with the specified character
+in your Perl script (or eval) near the specified column. Perhaps you tried
+to run a compressed script, a binary program, or a directory as a Perl program.
+
+=item Unrecognized escape \\%c in character class passed through in regex; marked by <-- HERE in m/%s/
+
+(W regexp) You used a backslash-character combination which is not
+recognized by Perl inside character classes. The character was
+understood literally, but this may change in a future version of Perl.
+The <-- HERE shows in the regular expression about where the
+escape was discovered.
+
+=item Unrecognized escape \\%c passed through
+
+(W misc) You used a backslash-character combination which is not
+recognized by Perl. The character was understood literally, but this may
+change in a future version of Perl.
+
+=item Unrecognized escape \\%c passed through in regex; marked by <-- HERE in m/%s/
+
+(W regexp) You used a backslash-character combination which is not
+recognized by Perl. The character was understood literally, but this may
+change in a future version of Perl.
+The <-- HERE shows in the regular expression about where the
+escape was discovered.
+
+=item Unrecognized signal name "%s"
+
+(F) You specified a signal name to the kill() function that was not
+recognized. Say C<kill -l> in your shell to see the valid signal names
+on your system.
+
+=item Unrecognized switch: -%s (-h will show valid options)
+
+(F) You specified an illegal option to Perl. Don't do that. (If you
+think you didn't do that, check the #! line to see if it's supplying the
+bad switch on your behalf.)
+
+=item Unsuccessful %s on filename containing newline
+
+(W newline) A file operation was attempted on a filename, and that
+operation failed, PROBABLY because the filename contained a newline,
+PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
+
+=item Unsupported directory function "%s" called
+
+(F) Your machine doesn't support opendir() and readdir().
+
+=item Unsupported function %s
+
+(F) This machine doesn't implement the indicated function, apparently.
+At least, Configure doesn't think so.
+
+=item Unsupported function fork
+
+(F) Your version of executable does not support forking.
+
+Note that under some systems, like OS/2, there may be different flavors
+of Perl executables, some of which may support fork, some not. Try
+changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
+
+=item Unsupported script encoding %s
+
+(F) Your program file begins with a Unicode Byte Order Mark (BOM) which
+declares it to be in a Unicode encoding that Perl cannot read.
+
+=item Unsupported socket function "%s" called
+
+(F) Your machine doesn't support the Berkeley socket mechanism, or at
+least that's what Configure thought.
+
+=item Unterminated attribute list
+
+(F) The lexer found something other than a simple identifier at the
+start of an attribute, and it wasn't a semicolon or the start of a
+block. Perhaps you terminated the parameter list of the previous
+attribute too soon. See L<attributes>.
+
+=item Unterminated attribute parameter in attribute list
+
+(F) The lexer saw an opening (left) parenthesis character while parsing
+an attribute list, but the matching closing (right) parenthesis
+character was not found. You may need to add (or remove) a backslash
+character to get your parentheses to balance. See L<attributes>.
+
+=item Unterminated compressed integer
+
+(F) An argument to unpack("w",...) was incompatible with the BER
+compressed integer format and could not be converted to an integer.
+See L<perlfunc/pack>.
+
+=item Unterminated verb pattern in regex; marked by <-- HERE in m/%s/
+
+(F) You used a pattern of the form C<(*VERB)> but did not terminate
+the pattern with a C<)>. Fix the pattern and retry.
+
+=item Unterminated verb pattern argument in regex; marked by <-- HERE in m/%s/
+
+(F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
+the pattern with a C<)>. Fix the pattern and retry.
+
+=item Unterminated \g{...} pattern in regex; marked by <-- HERE in m/%s/
+
+(F) You missed a close brace on a \g{..} pattern (group reference) in
+a regular expression. Fix the pattern and retry.
+
+=item Unterminated <> operator
+
+(F) The lexer saw a left angle bracket in a place where it was expecting
+a term, so it's looking for the corresponding right angle bracket, and
+not finding it. Chances are you left some needed parentheses out
+earlier in the line, and you really meant a "less than".
+
+=item untie attempted while %d inner references still exist
+
+(W untie) A copy of the object returned from C<tie> (or C<tied>) was
+still valid when C<untie> was called.
+
+=item Usage: POSIX::%s(%s)
+
+(F) You called a POSIX function with incorrect arguments.
+See L<POSIX/FUNCTIONS> for more information.
+
+=item Usage: Win32::%s(%s)
+
+(F) You called a Win32 function with incorrect arguments.
+See L<Win32> for more information.
+
+=item Useless (?-%s) - don't use /%s modifier in regex; marked by <-- HERE in m/%s/
+
+(W regexp) You have used an internal modifier such as (?-o) that has no
+meaning unless removed from the entire regexp:
+
+ if ($string =~ /(?-o)$pattern/o) { ... }
+
+must be written as
+
+ if ($string =~ /$pattern/) { ... }
+
+The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item Useless localization of %s
+
+(W syntax) The localization of lvalues such as C<local($x=10)> is
+legal, but in fact the local() currently has no effect. This may change at
+some point in the future, but in the meantime such code is discouraged.
+
+=item Useless (?%s) - use /%s modifier in regex; marked by <-- HERE in m/%s/
+
+(W regexp) You have used an internal modifier such as (?o) that has no
+meaning unless applied to the entire regexp:
+
+ if ($string =~ /(?o)$pattern/) { ... }
+
+must be written as
+
+ if ($string =~ /$pattern/o) { ... }
+
+The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
+=item Useless use of /d modifier in transliteration operator
+
+(W misc) You have used the /d modifier where the searchlist has the
+same length as the replacelist. See L<perlop> for more information
+about the /d modifier.
+
+=item Useless use of %s in void context
+
+(W void) You did something without a side effect in a context that does
+nothing with the return value, such as a statement that doesn't return a
+value from a block, or the left side of a scalar comma operator. Very
+often this points not to stupidity on your part, but a failure of Perl
+to parse your program the way you thought it would. For example, you'd
+get this if you mixed up your C precedence with Python precedence and
+said
+
+ $one, $two = 1, 2;
+
+when you meant to say
+
+ ($one, $two) = (1, 2);
+
+Another common error is to use ordinary parentheses to construct a list
+reference when you should be using square or curly brackets, for
+example, if you say
+
+ $array = (1,2);
+
+when you should have said
+
+ $array = [1,2];
+
+The square brackets explicitly turn a list value into a scalar value,
+while parentheses do not. So when a parenthesized list is evaluated in
+a scalar context, the comma is treated like C's comma operator, which
+throws away the left argument, which is not what you want. See
+L<perlref> for more on this.
+
+This warning will not be issued for numerical constants equal to 0 or 1
+since they are often used in statements like
+
+ 1 while sub_with_side_effects();
+
+String constants that would normally evaluate to 0 or 1 are warned
+about.
+
+=item Useless use of "re" pragma
+
+(W) You did C<use re;> without any arguments. That isn't very useful.
+
+=item Useless use of sort in scalar context
+
+(W void) You used sort in scalar context, as in :
+
+ my $x = sort @y;
+
+This is not very useful, and perl currently optimizes this away.
+
+=item Useless use of %s with no values
+
+(W syntax) You used the push() or unshift() function with no arguments
+apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
+usually have any effect on the array, so is completely useless. It's
+possible in principle that push(@tied_array) could have some effect
+if the array is tied to a class which implements a PUSH method. If so,
+you can write it as C<push(@tied_array,())> to avoid this warning.
+
+=item "use" not allowed in expression
+
+(F) The "use" keyword is recognized and executed at compile time, and
+returns no useful value. See L<perlmod>.
+
+=item Use of assignment to $[ is deprecated
+
+(D deprecated) The C<$[> variable (index of the first element in an array)
+is deprecated. See L<perlvar/"$[">.
+
+=item Use of bare << to mean <<"" is deprecated
+
+(D deprecated) You are now encouraged to use the explicitly quoted
+form if you wish to use an empty line as the terminator of the here-document.
+
+=item Use of comma-less variable list is deprecated
+
+(D deprecated) The values you give to a format should be
+separated by commas, not just aligned on a line.
+
+=item Use of chdir('') or chdir(undef) as chdir() deprecated
+
+(D deprecated) chdir() with no arguments is documented to change to
+$ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this
+behavior, but that has been deprecated. In future versions they
+will simply fail.
+
+Be careful to check that what you pass to chdir() is defined and not
+blank, else you might find yourself in your home directory.
+
+=item Use of /c modifier is meaningless in s///
+
+(W regexp) You used the /c modifier in a substitution. The /c
+modifier is not presently meaningful in substitutions.
+
+=item Use of /c modifier is meaningless without /g
+
+(W regexp) You used the /c modifier with a regex operand, but didn't
+use the /g modifier. Currently, /c is meaningful only when /g is
+used. (This may change in the future.)
+
+=item Use of := for an empty attribute list is deprecated
+
+(D deprecated) The construction C<my $x := 42> currently
+parses correctly in perl, being equivalent to C<my $x : = 42>
+(applying an empty attribute list to C<$x>). This useless
+construct is now deprecated, so C<:=> can be reclaimed as a new
+operator in the future.
+
+=item Use of freed value in iteration
+
+(F) Perhaps you modified the iterated array within the loop?
+This error is typically caused by code like the following:
+
+ @a = (3,4);
+ @a = () for (1,2,@a);
+
+You are not supposed to modify arrays while they are being iterated over.
+For speed and efficiency reasons, Perl internally does not do full
+reference-counting of iterated items, hence deleting such an item in the
+middle of an iteration causes Perl to see a freed value.
+
+=item Use of *glob{FILEHANDLE} is deprecated
+
+(D deprecated) You are now encouraged to use the shorter *glob{IO} form
+to access the filehandle slot within a typeglob.
+
+=item Use of /g modifier is meaningless in split
+
+(W regexp) You used the /g modifier on the pattern for a C<split>
+operator. Since C<split> always tries to match the pattern
+repeatedly, the C</g> has no effect.
+
+=item Use of "goto" to jump into a construct is deprecated
+
+(D deprecated) Using C<goto> to jump from an outer scope into an inner
+scope is deprecated and should be avoided.
+
+=item Use of inherited AUTOLOAD for non-method %s() is deprecated
+
+(D deprecated) As an (ahem) accidental feature, C<AUTOLOAD> subroutines
+are looked up as methods (using the C<@ISA> hierarchy) even when the
+subroutines to be autoloaded were called as plain functions (e.g.
+C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or C<<
+$obj->bar() >>).
+
+This bug will be rectified in future by using method lookup only for
+methods' C<AUTOLOAD>s. However, there is a significant base of existing
+code that may be using the old behavior. So, as an interim step, Perl
+currently issues an optional warning when non-methods use inherited
+C<AUTOLOAD>s.
+
+The simple rule is: Inheritance will not work when autoloading
+non-methods. The simple fix for old code is: In any module that used
+to depend on inheriting C<AUTOLOAD> for non-methods from a base class
+named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
+startup.
+
+In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
+you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
+C<use AutoLoader 'AUTOLOAD';>.
+
+=item Use of octal value above 377 is deprecated
+
+(D deprecated, W regexp) There is a constant in the regular expression whose
+value is interpeted by Perl as octal and larger than 377 (255 decimal, 0xFF
+hex). Perl may take this to mean different things depending on the rest of
+the regular expression. If you meant such an octal value, convert it to
+hexadecimal and use C<\xHH> or C<\x{HH}> instead. If you meant to have
+part of it mean a backreference, use C<\g> for that. See L<perlre>.
+
+=item Use of %s in printf format not supported
+
+(F) You attempted to use a feature of printf that is accessible from
+only C. This usually means there's a better way to do it in Perl.
+
+=item Use of %s is deprecated
+
+(D deprecated) The construct indicated is no longer recommended for use,
+generally because there's a better way to do it, and also because the
+old way has bad side effects.
+
+=item Use of -l on filehandle %s
+
+(W io) A filehandle represents an opened file, and when you opened the file
+it already went past any symlink you are presumably trying to look for.
+The operation returned C<undef>. Use a filename instead.
+
+=item Use of "package" with no arguments is deprecated
+
+(D deprecated) You used the C<package> keyword without specifying a package
+name. So no namespace is current at all. Using this can cause many
+otherwise reasonable constructs to fail in baffling ways. C<use strict;>
+instead.
+
+=item Use of reference "%s" as array index
+
+(W misc) You tried to use a reference as an array index; this probably
+isn't what you mean, because references in numerical context tend
+to be huge numbers, and so usually indicates programmer error.
+
+If you really do mean it, explicitly numify your reference, like so:
+C<$array[0+$ref]>. This warning is not given for overloaded objects,
+either, because you can overload the numification and stringification
+operators and then you assumably know what you are doing.
+
+=item Use of reserved word "%s" is deprecated
+
+(D deprecated) The indicated bareword is a reserved word. Future
+versions of perl may use it as a keyword, so you're better off either
+explicitly quoting the word in a manner appropriate for its context of
+use, or using a different name altogether. The warning can be
+suppressed for subroutine names by either adding a C<&> prefix, or using
+a package qualifier, e.g. C<&our()>, or C<Foo::our()>.
+
+=item Use of tainted arguments in %s is deprecated
+
+(W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
+arguments and at least one of them is tainted. This used to be allowed
+but will become a fatal error in a future version of perl. Untaint your
+arguments. See L<perlsec>.
+
+=item Use of uninitialized value%s
+
+(W uninitialized) An undefined value was used as if it were already
+defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
+To suppress this warning assign a defined value to your variables.
+
+To help you figure out what was undefined, perl will try to tell you the
+name of the variable (if any) that was undefined. In some cases it cannot
+do this, so it also tells you what operation you used the undefined value
+in. Note, however, that perl optimizes your program and the operation
+displayed in the warning may not necessarily appear literally in your
+program. For example, C<"that $foo"> is usually optimized into C<"that "
+. $foo>, and the warning will refer to the C<concatenation (.)> operator,
+even though there is no C<.> in your program.
+
+=item Using a hash as a reference is deprecated
+
+(D deprecated) You tried to use a hash as a reference, as in
+C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl <= 5.6.1
+used to allow this syntax, but shouldn't have. It is now deprecated, and will
+be removed in a future version.
+
+=item Using an array as a reference is deprecated
+
+(D deprecated) You tried to use an array as a reference, as in
+C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.6.1 used to
+allow this syntax, but shouldn't have. It is now deprecated, and will be
+removed in a future version.
+
+=item Using just the first character returned by \N{} in character class
+
+(W) A charnames handler may return a sequence of more than one character.
+Currently all but the first one are discarded when used in a regular
+expression pattern bracketed character class.
+
+=item Using just the first characters returned by \N{}
+
+(W) A charnames handler may return a sequence of characters. There is a finite
+limit as to the number of characters that can be used, which this sequence
+exceeded. In the message, the characters in the sequence are separated by
+dots, and each is shown by its ordinal in hex. Anything to the left of the
+C<HERE> was retained; anything to the right was discarded.
+
+=item UTF-16 surrogate %s
+
+(W utf8) You tried to generate half of a UTF-16 surrogate by
+requesting a Unicode character between the code points 0xD800 and
+0xDFFF (inclusive). That range is reserved exclusively for the use of
+UTF-16 encoding (by having two 16-bit UCS-2 characters); but Perl
+encodes its characters in UTF-8, so what you got is a very illegal
+character. If you really really know what you are doing you can turn off
+this warning by C<no warnings 'utf8';>.
+
+=item Value of %s can be "0"; test with defined()
+
+(W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
+C<each()>, or C<readdir()> as a boolean value. Each of these constructs
+can return a value of "0"; that would make the conditional expression
+false, which is probably not what you intended. When using these
+constructs in conditional expressions, test their values with the
+C<defined> operator.
+
+=item Value of CLI symbol "%s" too long
+
+(W misc) A warning peculiar to VMS. Perl tried to read the value of an
+%ENV element from a CLI symbol table, and found a resultant string
+longer than 1024 characters. The return value has been truncated to
+1024 characters.
+
+=item Variable "%s" is not available
+
+(W closure) During compilation, an inner named subroutine or eval is
+attempting to capture an outer lexical that is not currently available.
+This can happen for one of two reasons. First, the outer lexical may be
+declared in an outer anonymous subroutine that has not yet been created.
+(Remember that named subs are created at compile time, while anonymous
+subs are created at run-time.) For example,
+
+ sub { my $a; sub f { $a } }
+
+At the time that f is created, it can't capture the current value of $a,
+since the anonymous subroutine hasn't been created yet. Conversely,
+the following won't give a warning since the anonymous subroutine has by
+now been created and is live:
+
+ sub { my $a; eval 'sub f { $a }' }->();
+
+The second situation is caused by an eval accessing a variable that has
+gone out of scope, for example,
+
+ sub f {
+ my $a;
+ sub { eval '$a' }
+ }
+ f()->();
+
+Here, when the '$a' in the eval is being compiled, f() is not currently being
+executed, so its $a is not available for capture.
+
+=item Variable "%s" is not imported%s
+
+(F) While "use strict" in effect, you referred to a global variable that
+you apparently thought was imported from another module, because
+something else of the same name (usually a subroutine) is exported by
+that module. It usually means you put the wrong funny character on the
+front of your variable.
+
+=item Variable length lookbehind not implemented in m/%s/
+
+(F) Lookbehind is allowed only for subexpressions whose length is fixed and
+known at compile time. See L<perlre>.
+
+=item "%s" variable %s masks earlier declaration in same %s
+
+(W misc) A "my", "our" or "state" variable has been redeclared in the current
+scope or statement, effectively eliminating all access to the previous
+instance. This is almost always a typographical error. Note that the
+earlier variable will still exist until the end of the scope or until
+all closure referents to it are destroyed.
+
+=item Variable syntax
+
+(A) You've accidentally run your script through B<csh> instead
+of Perl. Check the #! line, or manually feed your script into
+Perl yourself.
+
+=item Variable "%s" will not stay shared
+
+(W closure) An inner (nested) I<named> subroutine is referencing a
+lexical variable defined in an outer named subroutine.
+
+When the inner subroutine is called, it will see the value of
+the outer subroutine's variable as it was before and during the *first*
+call to the outer subroutine; in this case, after the first call to the
+outer subroutine is complete, the inner and outer subroutines will no
+longer share a common value for the variable. In other words, the
+variable will no longer be shared.
+
+This problem can usually be solved by making the inner subroutine
+anonymous, using the C<sub {}> syntax. When inner anonymous subs that
+reference variables in outer subroutines are created, they
+are automatically rebound to the current values of such variables.
+
+=item Verb pattern '%s' has a mandatory argument in regex; marked by <-- HERE in m/%s/
+
+(F) You used a verb pattern that requires an argument. Supply an argument
+or check that you are using the right verb.
+
+=item Verb pattern '%s' may not have an argument in regex; marked by <-- HERE in m/%s/
+
+(F) You used a verb pattern that is not allowed an argument. Remove the
+argument or check that you are using the right verb.
+
+=item Version number must be a constant number
+
+(P) The attempt to translate a C<use Module n.n LIST> statement into
+its equivalent C<BEGIN> block found an internal inconsistency with
+the version number.
+
+=item Version string '%s' contains invalid data; ignoring: '%s'
+
+(W misc) The version string contains invalid characters at the end, which
+are being ignored.
+
+=item Warning: something's wrong
+
+(W) You passed warn() an empty string (the equivalent of C<warn "">) or
+you called it with no args and C<$@> was empty.
+
+=item Warning: unable to close filehandle %s properly
+
+(S) The implicit close() done by an open() got an error indication on
+the close(). This usually indicates your file system ran out of disk
+space.
+
+=item Warning: Use of "%s" without parentheses is ambiguous
+
+(S ambiguous) You wrote a unary operator followed by something that
+looks like a binary operator that could also have been interpreted as a
+term or unary operator. For instance, if you know that the rand
+function has a default argument of 1.0, and you write
+
+ rand + 5;
+
+you may THINK you wrote the same thing as
+
+ rand() + 5;
+
+but in actual fact, you got
+
+ rand(+5);
+
+So put in parentheses to say what you really mean.
+
+=item Wide character in %s
+
+(S utf8) Perl met a wide character (>255) when it wasn't expecting
+one. This warning is by default on for I/O (like print). The easiest
+way to quiet this warning is simply to add the C<:utf8> layer to the
+output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
+warning is to add C<no warnings 'utf8';> but that is often closer to
+cheating. In general, you are supposed to explicitly mark the
+filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
+
+=item Within []-length '%c' not allowed
+
+(F) The count in the (un)pack template may be replaced by C<[TEMPLATE]> only if
+C<TEMPLATE> always matches the same amount of packed bytes that can be
+determined from the template alone. This is not possible if it contains an
+of the codes @, /, U, u, w or a *-length. Redesign the template.
+
+=item write() on closed filehandle %s
+
+(W closed) The filehandle you're writing to got itself closed sometime
+before now. Check your control flow.
+
+=item %s "\x%s" does not map to Unicode
+
+When reading in different encodings Perl tries to map everything
+into Unicode characters. The bytes you read in are not legal in
+this encoding, for example
+
+ utf8 "\xE4" does not map to Unicode
+
+if you try to read in the a-diaereses Latin-1 as UTF-8.
+
+=item 'X' outside of string
+
+(F) You had a (un)pack template that specified a relative position before
+the beginning of the string being (un)packed. See L<perlfunc/pack>.
+
+=item 'x' outside of string in unpack
+
+(F) You had a pack template that specified a relative position after
+the end of the string being unpacked. See L<perlfunc/pack>.
+
+=item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
+
+(F) And you probably never will, because you probably don't have the
+sources to your kernel, and your vendor probably doesn't give a rip
+about what you want. Your best bet is to put a setuid C wrapper around
+your script.
+
+=item You need to quote "%s"
+
+(W syntax) You assigned a bareword as a signal handler name.
+Unfortunately, you already have a subroutine of that name declared,
+which means that Perl 5 will try to call the subroutine when the
+assignment is executed, which is probably not what you want. (If it IS
+what you want, put an & in front.)
+
+=item Your random numbers are not that random
+
+(F) When trying to initialise the random seed for hashes, Perl could
+not get any randomness out of your system. This usually indicates
+Something Very Wrong.
+
+=back
+
+=head1 SEE ALSO
+
+L<warnings>, L<perllexwarn>.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perldoc.pod b/Master/tlpkg/tlperl/lib/pods/perldoc.pod
new file mode 100644
index 00000000000..883a6184603
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldoc.pod
@@ -0,0 +1,270 @@
+
+=head1 NAME
+
+perldoc - Look up Perl documentation in Pod format.
+
+=head1 SYNOPSIS
+
+B<perldoc> [B<-h>] [B<-D>] [B<-t>] [B<-u>] [B<-m>] [B<-l>] [B<-F>]
+[B<-i>] [B<-V>] [B<-T>] [B<-r>]
+[B<-dI<destination_file>>]
+[B<-oI<formatname>>]
+[B<-MI<FormatterClassName>>]
+[B<-wI<formatteroption:value>>]
+[B<-n>I<nroff-replacement>]
+[B<-X>]
+[B<-L> I<language_code>]
+PageName|ModuleName|ProgramName
+
+B<perldoc> B<-f> BuiltinFunction
+
+B<perldoc> B<-L> it B<-f> BuiltinFunction
+
+B<perldoc> B<-q> FAQ Keyword
+
+B<perldoc> B<-L> fr B<-q> FAQ Keyword
+
+B<perldoc> B<-v> PerlVariable
+
+See below for more description of the switches.
+
+=head1 DESCRIPTION
+
+I<perldoc> looks up a piece of documentation in .pod format that is embedded
+in the perl installation tree or in a perl script, and displays it via
+C<pod2man | nroff -man | $PAGER>. (In addition, if running under HP-UX,
+C<col -x> will be used.) This is primarily used for the documentation for
+the perl library modules.
+
+Your system may also have man pages installed for those modules, in
+which case you can probably just use the man(1) command.
+
+If you are looking for a table of contents to the Perl library modules
+documentation, see the L<perltoc> page.
+
+=head1 OPTIONS
+
+=over 5
+
+=item B<-h>
+
+Prints out a brief B<h>elp message.
+
+=item B<-D>
+
+B<D>escribes search for the item in B<d>etail.
+
+=item B<-t>
+
+Display docs using plain B<t>ext converter, instead of nroff. This may be faster,
+but it probably won't look as nice.
+
+=item B<-u>
+
+Skip the real Pod formatting, and just show the raw Pod source (B<U>nformatted)
+
+=item B<-m> I<module>
+
+Display the entire module: both code and unformatted pod documentation.
+This may be useful if the docs don't explain a function in the detail
+you need, and you'd like to inspect the code directly; perldoc will find
+the file for you and simply hand it off for display.
+
+=item B<-l>
+
+Display onB<l>y the file name of the module found.
+
+=item B<-F>
+
+Consider arguments as file names; no search in directories will be performed.
+
+=item B<-f> I<perlfunc>
+
+The B<-f> option followed by the name of a perl built in function will
+extract the documentation of this function from L<perlfunc>.
+
+Example:
+
+ perldoc -f sprintf
+
+
+=item B<-q> I<perlfaq-search-regexp>
+
+The B<-q> option takes a regular expression as an argument. It will search
+the B<q>uestion headings in perlfaq[1-9] and print the entries matching
+the regular expression.
+
+Example:
+
+ perldoc -q shuffle
+
+
+=item B<-v> I<perlvar>
+
+The B<-v> option followed by the name of a Perl predefined variable will
+extract the documentation of this variable from L<perlvar>.
+
+Examples:
+
+ perldoc -v '$"'
+ perldoc -v @+
+ perldoc -v DATA
+
+
+=item B<-T>
+
+This specifies that the output is not to be sent to a pager, but is to
+be sent right to STDOUT.
+
+=item B<-d> I<destination-filename>
+
+This specifies that the output is to be sent neither to a pager nor
+to STDOUT, but is to be saved to the specified filename. Example:
+C<perldoc -oLaTeX -dtextwrapdocs.tex Text::Wrap>
+
+=item B<-o> I<output-formatname>
+
+This specifies that you want Perldoc to try using a Pod-formatting
+class for the output format that you specify. For example:
+C<-oman>. This is actually just a wrapper around the C<-M> switch;
+using C<-oI<formatname>> just looks for a loadable class by adding
+that format name (with different capitalizations) to the end of
+different classname prefixes.
+
+For example, C<-oLaTeX> currently tries all of the following classes:
+Pod::Perldoc::ToLaTeX Pod::Perldoc::Tolatex Pod::Perldoc::ToLatex
+Pod::Perldoc::ToLATEX Pod::Simple::LaTeX Pod::Simple::latex
+Pod::Simple::Latex Pod::Simple::LATEX Pod::LaTeX Pod::latex Pod::Latex
+Pod::LATEX.
+
+=item B<-M> I<module-name>
+
+This specifies the module that you want to try using for formatting the
+pod. The class must at least provide a C<parse_from_file> method.
+For example: C<perldoc -MPod::Perldoc::ToChecker>.
+
+You can specify several classes to try by joining them with commas
+or semicolons, as in C<-MTk::SuperPod;Tk::Pod>.
+
+=item B<-w> I<option:value> or B<-w> I<option>
+
+This specifies an option to call the formatter B<w>ith. For example,
+C<-w textsize:15> will call
+C<< $formatter->textsize(15) >> on the formatter object before it is
+used to format the object. For this to be valid, the formatter class
+must provide such a method, and the value you pass should be valid.
+(So if C<textsize> expects an integer, and you do C<-w textsize:big>,
+expect trouble.)
+
+You can use C<-w optionname> (without a value) as shorthand for
+C<-w optionname:I<TRUE>>. This is presumably useful in cases of on/off
+features like: C<-w page_numbering>.
+
+You can use a "=" instead of the ":", as in: C<-w textsize=15>. This
+might be more (or less) convenient, depending on what shell you use.
+
+=item B<-X>
+
+Use an index if it is present. The B<-X> option looks for an entry
+whose basename matches the name given on the command line in the file
+C<$Config{archlib}/pod.idx>. The F<pod.idx> file should contain fully
+qualified filenames, one per line.
+
+=item B<-L> I<language_code>
+
+This allows to specify the I<language code> for desired language translation.
+If C<POD2::E<lt>language_codeE<gt>> package doesn't exist (or isn't installed
+in your system), the switch will be ignored.
+All available translation packages should be found under the C<POD2::>
+namespace. See L<POD2::IT> (or L<POD2::FR>) in order to see how to create and
+integrate new localized C<POD2::*> pod documentation packages in
+L<Pod::Perldoc>.
+
+=item B<PageName|ModuleName|ProgramName>
+
+The item you want to look up. Nested modules (such as C<File::Basename>)
+are specified either as C<File::Basename> or C<File/Basename>. You may also
+give a descriptive name of a page, such as C<perlfunc>.
+
+For simple names like 'foo', when the normal search fails to find
+a matching page, a search with the "perl" prefix is tried as well.
+So "perldoc intro" is enough to find/render "perlintro.pod".
+
+=item B<-n> I<some-formatter>
+
+Specify replacement for nroff
+
+=item B<-r>
+
+Recursive search.
+
+=item B<-i>
+
+Ignore case.
+
+=item B<-V>
+
+Displays the version of perldoc you're running.
+
+=back
+
+
+
+=head1 SECURITY
+
+Because B<perldoc> does not run properly tainted, and is known to
+have security issues, when run as the superuser it will attempt to
+drop privileges by setting the effective and real IDs to nobody's
+or nouser's account, or -2 if unavailable. If it cannot relinquish
+its privileges, it will not run.
+
+
+=head1 ENVIRONMENT
+
+Any switches in the C<PERLDOC> environment variable will be used before the
+command line arguments.
+
+Useful values for C<PERLDOC> include C<-oman>, C<-otext>, C<-otk>, C<-ortf>,
+C<-oxml>, and so on, depending on what modules you have on hand; or
+exactly specify the formatter class with C<-MPod::Perldoc::ToMan>
+or the like.
+
+C<perldoc> also searches directories
+specified by the C<PERL5LIB> (or C<PERLLIB> if C<PERL5LIB> is not
+defined) and C<PATH> environment variables.
+(The latter is so that embedded pods for executables, such as
+C<perldoc> itself, are available.)
+
+C<perldoc> will use, in order of preference, the pager defined in
+C<PERLDOC_PAGER>, C<MANPAGER>, or C<PAGER> before trying to find a pager
+on its own. (C<MANPAGER> is not used if C<perldoc> was told to display
+plain text or unformatted pod.)
+
+One useful value for C<PERLDOC_PAGER> is C<less -+C -E>.
+
+Having PERLDOCDEBUG set to a positive integer will make perldoc emit
+even more descriptive output than the C<-v> switch does; the higher the
+number, the more it emits.
+
+
+=head1 CHANGES
+
+Up to 3.14_05, the switch B<-v> was used to produce verbose
+messages of B<perldoc> operation, which is now enabled by B<-D>.
+
+=head1 SEE ALSO
+
+L<perlpod>, L<Pod::Perldoc>
+
+=head1 AUTHOR
+
+Current maintainer: Adriano R. Ferreira <ferreira@cpan.org>
+
+Past contributors are:
+Sean M. Burke <sburke@cpan.org>,
+Kenneth Albanowski <kjahds@kjahds.com>,
+Andy Dougherty <doughera@lafcol.lafayette.edu>,
+and many others.
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perldos.pod b/Master/tlpkg/tlperl/lib/pods/perldos.pod
new file mode 100644
index 00000000000..ef3578f8894
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldos.pod
@@ -0,0 +1,331 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perldos - Perl under DOS, W31, W95.
+
+=head1 SYNOPSIS
+
+These are instructions for building Perl under DOS (or w??), using
+DJGPP v2.03 or later. Under w95 long filenames are supported.
+
+=head1 DESCRIPTION
+
+Before you start, you should glance through the README file
+found in the top-level directory where the Perl distribution
+was extracted. Make sure you read and understand the terms under
+which this software is being distributed.
+
+This port currently supports MakeMaker (the set of modules that
+is used to build extensions to perl). Therefore, you should be
+able to build and install most extensions found in the CPAN sites.
+
+Detailed instructions on how to build and install perl extension
+modules, including XS-type modules, is included. See 'BUILDING AND
+INSTALLING MODULES'.
+
+=head2 Prerequisites for Compiling Perl on DOS
+
+=over 4
+
+=item DJGPP
+
+DJGPP is a port of GNU C/C++ compiler and development tools to 32-bit,
+protected-mode environment on Intel 32-bit CPUs running MS-DOS and compatible
+operating systems, by DJ Delorie <dj@delorie.com> and friends.
+
+For more details (FAQ), check out the home of DJGPP at:
+
+ http://www.delorie.com/djgpp/
+
+If you have questions about DJGPP, try posting to the DJGPP newsgroup:
+comp.os.msdos.djgpp, or use the email gateway djgpp@delorie.com.
+
+You can find the full DJGPP distribution on any of the mirrors listed here:
+
+ http://www.delorie.com/djgpp/getting.html
+
+You need the following files to build perl (or add new modules):
+
+ v2/djdev203.zip
+ v2gnu/bnu2112b.zip
+ v2gnu/gcc2953b.zip
+ v2gnu/bsh204b.zip
+ v2gnu/mak3791b.zip
+ v2gnu/fil40b.zip
+ v2gnu/sed3028b.zip
+ v2gnu/txt20b.zip
+ v2gnu/dif272b.zip
+ v2gnu/grep24b.zip
+ v2gnu/shl20jb.zip
+ v2gnu/gwk306b.zip
+ v2misc/csdpmi5b.zip
+
+or possibly any newer version.
+
+=item Pthreads
+
+Thread support is not tested in this version of the djgpp perl.
+
+=back
+
+=head2 Shortcomings of Perl under DOS
+
+Perl under DOS lacks some features of perl under UNIX because of
+deficiencies in the UNIX-emulation, most notably:
+
+=over 4
+
+=item *
+
+fork() and pipe()
+
+=item *
+
+some features of the UNIX filesystem regarding link count and file dates
+
+=item *
+
+in-place operation is a little bit broken with short filenames
+
+=item *
+
+sockets
+
+=back
+
+=head2 Building Perl on DOS
+
+=over 4
+
+=item *
+
+Unpack the source package F<perl5.8*.tar.gz> with djtarx. If you want
+to use long file names under w95 and also to get Perl to pass all its
+tests, don't forget to use
+
+ set LFN=y
+ set FNCASE=y
+
+before unpacking the archive.
+
+=item *
+
+Create a "symlink" or copy your bash.exe to sh.exe in your C<($DJDIR)/bin>
+directory.
+
+ ln -s bash.exe sh.exe
+
+[If you have the recommended version of bash for DJGPP, this is already
+done for you.]
+
+And make the C<SHELL> environment variable point to this F<sh.exe>:
+
+ set SHELL=c:/djgpp/bin/sh.exe (use full path name!)
+
+You can do this in F<djgpp.env> too. Add this line BEFORE any section
+definition:
+
+ +SHELL=%DJDIR%/bin/sh.exe
+
+=item *
+
+If you have F<split.exe> and F<gsplit.exe> in your path, then rename
+F<split.exe> to F<djsplit.exe>, and F<gsplit.exe> to F<split.exe>.
+Copy or link F<gecho.exe> to F<echo.exe> if you don't have F<echo.exe>.
+Copy or link F<gawk.exe> to F<awk.exe> if you don't have F<awk.exe>.
+
+[If you have the recommended versions of djdev, shell utilities and
+gawk, all these are already done for you, and you will not need to do
+anything.]
+
+=item *
+
+Chdir to the djgpp subdirectory of perl toplevel and type the following
+commands:
+
+ set FNCASE=y
+ configure.bat
+
+This will do some preprocessing then run the Configure script for you.
+The Configure script is interactive, but in most cases you just need to
+press ENTER. The "set" command ensures that DJGPP preserves the letter
+case of file names when reading directories. If you already issued this
+set command when unpacking the archive, and you are in the same DOS
+session as when you unpacked the archive, you don't have to issue the
+set command again. This command is necessary *before* you start to
+(re)configure or (re)build perl in order to ensure both that perl builds
+correctly and that building XS-type modules can succeed. See the DJGPP
+info entry for "_preserve_fncase" for more information:
+
+ info libc alphabetical _preserve_fncase
+
+If the script says that your package is incomplete, and asks whether
+to continue, just answer with Y (this can only happen if you don't use
+long filenames or forget to issue "set FNCASE=y" first).
+
+When Configure asks about the extensions, I suggest IO and Fcntl,
+and if you want database handling then SDBM_File or GDBM_File
+(you need to install gdbm for this one). If you want to use the
+POSIX extension (this is the default), make sure that the stack
+size of your F<cc1.exe> is at least 512kbyte (you can check this
+with: C<stubedit cc1.exe>).
+
+You can use the Configure script in non-interactive mode too.
+When I built my F<perl.exe>, I used something like this:
+
+ configure.bat -des
+
+You can find more info about Configure's command line switches in
+the F<INSTALL> file.
+
+When the script ends, and you want to change some values in the
+generated F<config.sh> file, then run
+
+ sh Configure -S
+
+after you made your modifications.
+
+IMPORTANT: if you use this C<-S> switch, be sure to delete the CONFIG
+environment variable before running the script:
+
+ set CONFIG=
+
+=item *
+
+Now you can compile Perl. Type:
+
+ make
+
+=back
+
+=head2 Testing Perl on DOS
+
+Type:
+
+ make test
+
+If you're lucky you should see "All tests successful". But there can be
+a few failed subtests (less than 5 hopefully) depending on some external
+conditions (e.g. some subtests fail under linux/dosemu or plain dos
+with short filenames only).
+
+=head2 Installation of Perl on DOS
+
+Type:
+
+ make install
+
+This will copy the newly compiled perl and libraries into your DJGPP
+directory structure. Perl.exe and the utilities go into C<($DJDIR)/bin>,
+and the library goes under C<($DJDIR)/lib/perl5>. The pod documentation
+goes under C<($DJDIR)/lib/perl5/pod>.
+
+=head1 BUILDING AND INSTALLING MODULES ON DOS
+
+=head2 Building Prerequisites for Perl on DOS
+
+For building and installing non-XS modules, all you need is a working
+perl under DJGPP. Non-XS modules do not require re-linking the perl
+binary, and so are simpler to build and install.
+
+XS-type modules do require re-linking the perl binary, because part of
+an XS module is written in "C", and has to be linked together with the
+perl binary to be executed. This is required because perl under DJGPP
+is built with the "static link" option, due to the lack of "dynamic
+linking" in the DJGPP environment.
+
+Because XS modules require re-linking of the perl binary, you need both
+the perl binary distribution and the perl source distribution to build
+an XS extension module. In addition, you will have to have built your
+perl binary from the source distribution so that all of the components
+of the perl binary are available for the required link step.
+
+=head2 Unpacking CPAN Modules on DOS
+
+First, download the module package from CPAN (e.g., the "Comma Separated
+Value" text package, Text-CSV-0.01.tar.gz). Then expand the contents of
+the package into some location on your disk. Most CPAN modules are
+built with an internal directory structure, so it is usually safe to
+expand it in the root of your DJGPP installation. Some people prefer to
+locate source trees under /usr/src (i.e., C<($DJDIR)/usr/src>), but you may
+put it wherever seems most logical to you, *EXCEPT* under the same
+directory as your perl source code. There are special rules that apply
+to modules which live in the perl source tree that do not apply to most
+of the modules in CPAN.
+
+Unlike other DJGPP packages, which are normal "zip" files, most CPAN
+module packages are "gzipped tarballs". Recent versions of WinZip will
+safely unpack and expand them, *UNLESS* they have zero-length files. It
+is a known WinZip bug (as of v7.0) that it will not extract zero-length
+files.
+
+From the command line, you can use the djtar utility provided with DJGPP
+to unpack and expand these files. For example:
+
+ C:\djgpp>djtarx -v Text-CSV-0.01.tar.gz
+
+This will create the new directory C<($DJDIR)/Text-CSV-0.01>, filling
+it with the source for this module.
+
+=head2 Building Non-XS Modules on DOS
+
+To build a non-XS module, you can use the standard module-building
+instructions distributed with perl modules.
+
+ perl Makefile.PL
+ make
+ make test
+ make install
+
+This is sufficient because non-XS modules install only ".pm" files and
+(sometimes) pod and/or man documentation. No re-linking of the perl
+binary is needed to build, install or use non-XS modules.
+
+=head2 Building XS Modules on DOS
+
+To build an XS module, you must use the standard module-building
+instructions distributed with perl modules *PLUS* three extra
+instructions specific to the DJGPP "static link" build environment.
+
+ set FNCASE=y
+ perl Makefile.PL
+ make
+ make perl
+ make test
+ make -f Makefile.aperl inst_perl MAP_TARGET=perl.exe
+ make install
+
+The first extra instruction sets DJGPP's FNCASE environment variable so
+that the new perl binary which you must build for an XS-type module will
+build correctly. The second extra instruction re-builds the perl binary
+in your module directory before you run "make test", so that you are
+testing with the new module code you built with "make". The third extra
+instruction installs the perl binary from your module directory into the
+standard DJGPP binary directory, C<($DJDIR)/bin>, replacing your
+previous perl binary.
+
+Note that the MAP_TARGET value *must* have the ".exe" extension or you
+will not create a "perl.exe" to replace the one in C<($DJDIR)/bin>.
+
+When you are done, the XS-module install process will have added information
+to your "perllocal" information telling that the perl binary has been replaced,
+and what module was installed. You can view this information at any time
+by using the command:
+
+ perl -S perldoc perllocal
+
+=head1 AUTHOR
+
+Laszlo Molnar, F<laszlo.molnar@eth.ericsson.se> [Installing/building perl]
+
+Peter J. Farley III F<pjfarley@banet.net> [Building/installing modules]
+
+=head1 SEE ALSO
+
+perl(1).
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perldsc.pod b/Master/tlpkg/tlperl/lib/pods/perldsc.pod
new file mode 100644
index 00000000000..b30948c32ab
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perldsc.pod
@@ -0,0 +1,847 @@
+=head1 NAME
+X<data structure> X<complex data structure> X<struct>
+
+perldsc - Perl Data Structures Cookbook
+
+=head1 DESCRIPTION
+
+The single feature most sorely lacking in the Perl programming language
+prior to its 5.0 release was complex data structures. Even without direct
+language support, some valiant programmers did manage to emulate them, but
+it was hard work and not for the faint of heart. You could occasionally
+get away with the C<$m{$AoA,$b}> notation borrowed from B<awk> in which the
+keys are actually more like a single concatenated string C<"$AoA$b">, but
+traversal and sorting were difficult. More desperate programmers even
+hacked Perl's internal symbol table directly, a strategy that proved hard
+to develop and maintain--to put it mildly.
+
+The 5.0 release of Perl let us have complex data structures. You
+may now write something like this and all of a sudden, you'd have an array
+with three dimensions!
+
+ for $x (1 .. 10) {
+ for $y (1 .. 10) {
+ for $z (1 .. 10) {
+ $AoA[$x][$y][$z] =
+ $x ** $y + $z;
+ }
+ }
+ }
+
+Alas, however simple this may appear, underneath it's a much more
+elaborate construct than meets the eye!
+
+How do you print it out? Why can't you say just C<print @AoA>? How do
+you sort it? How can you pass it to a function or get one of these back
+from a function? Is it an object? Can you save it to disk to read
+back later? How do you access whole rows or columns of that matrix? Do
+all the values have to be numeric?
+
+As you see, it's quite easy to become confused. While some small portion
+of the blame for this can be attributed to the reference-based
+implementation, it's really more due to a lack of existing documentation with
+examples designed for the beginner.
+
+This document is meant to be a detailed but understandable treatment of the
+many different sorts of data structures you might want to develop. It
+should also serve as a cookbook of examples. That way, when you need to
+create one of these complex data structures, you can just pinch, pilfer, or
+purloin a drop-in example from here.
+
+Let's look at each of these possible constructs in detail. There are separate
+sections on each of the following:
+
+=over 5
+
+=item * arrays of arrays
+
+=item * hashes of arrays
+
+=item * arrays of hashes
+
+=item * hashes of hashes
+
+=item * more elaborate constructs
+
+=back
+
+But for now, let's look at general issues common to all
+these types of data structures.
+
+=head1 REFERENCES
+X<reference> X<dereference> X<dereferencing> X<pointer>
+
+The most important thing to understand about all data structures in
+Perl--including multidimensional arrays--is that even though they might
+appear otherwise, Perl C<@ARRAY>s and C<%HASH>es are all internally
+one-dimensional. They can hold only scalar values (meaning a string,
+number, or a reference). They cannot directly contain other arrays or
+hashes, but instead contain I<references> to other arrays or hashes.
+X<multidimensional array> X<array, multidimensional>
+
+You can't use a reference to an array or hash in quite the same way that you
+would a real array or hash. For C or C++ programmers unused to
+distinguishing between arrays and pointers to the same, this can be
+confusing. If so, just think of it as the difference between a structure
+and a pointer to a structure.
+
+You can (and should) read more about references in L<perlref>.
+Briefly, references are rather like pointers that know what they
+point to. (Objects are also a kind of reference, but we won't be needing
+them right away--if ever.) This means that when you have something which
+looks to you like an access to a two-or-more-dimensional array and/or hash,
+what's really going on is that the base type is
+merely a one-dimensional entity that contains references to the next
+level. It's just that you can I<use> it as though it were a
+two-dimensional one. This is actually the way almost all C
+multidimensional arrays work as well.
+
+ $array[7][12] # array of arrays
+ $array[7]{string} # array of hashes
+ $hash{string}[7] # hash of arrays
+ $hash{string}{'another string'} # hash of hashes
+
+Now, because the top level contains only references, if you try to print
+out your array in with a simple print() function, you'll get something
+that doesn't look very nice, like this:
+
+ @AoA = ( [2, 3], [4, 5, 7], [0] );
+ print $AoA[1][2];
+ 7
+ print @AoA;
+ ARRAY(0x83c38)ARRAY(0x8b194)ARRAY(0x8b1d0)
+
+
+That's because Perl doesn't (ever) implicitly dereference your variables.
+If you want to get at the thing a reference is referring to, then you have
+to do this yourself using either prefix typing indicators, like
+C<${$blah}>, C<@{$blah}>, C<@{$blah[$i]}>, or else postfix pointer arrows,
+like C<$a-E<gt>[3]>, C<$h-E<gt>{fred}>, or even C<$ob-E<gt>method()-E<gt>[3]>.
+
+=head1 COMMON MISTAKES
+
+The two most common mistakes made in constructing something like
+an array of arrays is either accidentally counting the number of
+elements or else taking a reference to the same memory location
+repeatedly. Here's the case where you just get the count instead
+of a nested array:
+
+ for $i (1..10) {
+ @array = somefunc($i);
+ $AoA[$i] = @array; # WRONG!
+ }
+
+That's just the simple case of assigning an array to a scalar and getting
+its element count. If that's what you really and truly want, then you
+might do well to consider being a tad more explicit about it, like this:
+
+ for $i (1..10) {
+ @array = somefunc($i);
+ $counts[$i] = scalar @array;
+ }
+
+Here's the case of taking a reference to the same memory location
+again and again:
+
+ for $i (1..10) {
+ @array = somefunc($i);
+ $AoA[$i] = \@array; # WRONG!
+ }
+
+So, what's the big problem with that? It looks right, doesn't it?
+After all, I just told you that you need an array of references, so by
+golly, you've made me one!
+
+Unfortunately, while this is true, it's still broken. All the references
+in @AoA refer to the I<very same place>, and they will therefore all hold
+whatever was last in @array! It's similar to the problem demonstrated in
+the following C program:
+
+ #include <pwd.h>
+ main() {
+ struct passwd *getpwnam(), *rp, *dp;
+ rp = getpwnam("root");
+ dp = getpwnam("daemon");
+
+ printf("daemon name is %s\nroot name is %s\n",
+ dp->pw_name, rp->pw_name);
+ }
+
+Which will print
+
+ daemon name is daemon
+ root name is daemon
+
+The problem is that both C<rp> and C<dp> are pointers to the same location
+in memory! In C, you'd have to remember to malloc() yourself some new
+memory. In Perl, you'll want to use the array constructor C<[]> or the
+hash constructor C<{}> instead. Here's the right way to do the preceding
+broken code fragments:
+X<[]> X<{}>
+
+ for $i (1..10) {
+ @array = somefunc($i);
+ $AoA[$i] = [ @array ];
+ }
+
+The square brackets make a reference to a new array with a I<copy>
+of what's in @array at the time of the assignment. This is what
+you want.
+
+Note that this will produce something similar, but it's
+much harder to read:
+
+ for $i (1..10) {
+ @array = 0 .. $i;
+ @{$AoA[$i]} = @array;
+ }
+
+Is it the same? Well, maybe so--and maybe not. The subtle difference
+is that when you assign something in square brackets, you know for sure
+it's always a brand new reference with a new I<copy> of the data.
+Something else could be going on in this new case with the C<@{$AoA[$i]}>
+dereference on the left-hand-side of the assignment. It all depends on
+whether C<$AoA[$i]> had been undefined to start with, or whether it
+already contained a reference. If you had already populated @AoA with
+references, as in
+
+ $AoA[3] = \@another_array;
+
+Then the assignment with the indirection on the left-hand-side would
+use the existing reference that was already there:
+
+ @{$AoA[3]} = @array;
+
+Of course, this I<would> have the "interesting" effect of clobbering
+@another_array. (Have you ever noticed how when a programmer says
+something is "interesting", that rather than meaning "intriguing",
+they're disturbingly more apt to mean that it's "annoying",
+"difficult", or both? :-)
+
+So just remember always to use the array or hash constructors with C<[]>
+or C<{}>, and you'll be fine, although it's not always optimally
+efficient.
+
+Surprisingly, the following dangerous-looking construct will
+actually work out fine:
+
+ for $i (1..10) {
+ my @array = somefunc($i);
+ $AoA[$i] = \@array;
+ }
+
+That's because my() is more of a run-time statement than it is a
+compile-time declaration I<per se>. This means that the my() variable is
+remade afresh each time through the loop. So even though it I<looks> as
+though you stored the same variable reference each time, you actually did
+not! This is a subtle distinction that can produce more efficient code at
+the risk of misleading all but the most experienced of programmers. So I
+usually advise against teaching it to beginners. In fact, except for
+passing arguments to functions, I seldom like to see the gimme-a-reference
+operator (backslash) used much at all in code. Instead, I advise
+beginners that they (and most of the rest of us) should try to use the
+much more easily understood constructors C<[]> and C<{}> instead of
+relying upon lexical (or dynamic) scoping and hidden reference-counting to
+do the right thing behind the scenes.
+
+In summary:
+
+ $AoA[$i] = [ @array ]; # usually best
+ $AoA[$i] = \@array; # perilous; just how my() was that array?
+ @{ $AoA[$i] } = @array; # way too tricky for most programmers
+
+
+=head1 CAVEAT ON PRECEDENCE
+X<dereference, precedence> X<dereferencing, precedence>
+
+Speaking of things like C<@{$AoA[$i]}>, the following are actually the
+same thing:
+X<< -> >>
+
+ $aref->[2][2] # clear
+ $$aref[2][2] # confusing
+
+That's because Perl's precedence rules on its five prefix dereferencers
+(which look like someone swearing: C<$ @ * % &>) make them bind more
+tightly than the postfix subscripting brackets or braces! This will no
+doubt come as a great shock to the C or C++ programmer, who is quite
+accustomed to using C<*a[i]> to mean what's pointed to by the I<i'th>
+element of C<a>. That is, they first take the subscript, and only then
+dereference the thing at that subscript. That's fine in C, but this isn't C.
+
+The seemingly equivalent construct in Perl, C<$$aref[$i]> first does
+the deref of $aref, making it take $aref as a reference to an
+array, and then dereference that, and finally tell you the I<i'th> value
+of the array pointed to by $AoA. If you wanted the C notion, you'd have to
+write C<${$AoA[$i]}> to force the C<$AoA[$i]> to get evaluated first
+before the leading C<$> dereferencer.
+
+=head1 WHY YOU SHOULD ALWAYS C<use strict>
+
+If this is starting to sound scarier than it's worth, relax. Perl has
+some features to help you avoid its most common pitfalls. The best
+way to avoid getting confused is to start every program like this:
+
+ #!/usr/bin/perl -w
+ use strict;
+
+This way, you'll be forced to declare all your variables with my() and
+also disallow accidental "symbolic dereferencing". Therefore if you'd done
+this:
+
+ my $aref = [
+ [ "fred", "barney", "pebbles", "bambam", "dino", ],
+ [ "homer", "bart", "marge", "maggie", ],
+ [ "george", "jane", "elroy", "judy", ],
+ ];
+
+ print $aref[2][2];
+
+The compiler would immediately flag that as an error I<at compile time>,
+because you were accidentally accessing C<@aref>, an undeclared
+variable, and it would thereby remind you to write instead:
+
+ print $aref->[2][2]
+
+=head1 DEBUGGING
+X<data structure, debugging> X<complex data structure, debugging>
+X<AoA, debugging> X<HoA, debugging> X<AoH, debugging> X<HoH, debugging>
+X<array of arrays, debugging> X<hash of arrays, debugging>
+X<array of hashes, debugging> X<hash of hashes, debugging>
+
+Before version 5.002, the standard Perl debugger didn't do a very nice job of
+printing out complex data structures. With 5.002 or above, the
+debugger includes several new features, including command line editing as
+well as the C<x> command to dump out complex data structures. For
+example, given the assignment to $AoA above, here's the debugger output:
+
+ DB<1> x $AoA
+ $AoA = ARRAY(0x13b5a0)
+ 0 ARRAY(0x1f0a24)
+ 0 'fred'
+ 1 'barney'
+ 2 'pebbles'
+ 3 'bambam'
+ 4 'dino'
+ 1 ARRAY(0x13b558)
+ 0 'homer'
+ 1 'bart'
+ 2 'marge'
+ 3 'maggie'
+ 2 ARRAY(0x13b540)
+ 0 'george'
+ 1 'jane'
+ 2 'elroy'
+ 3 'judy'
+
+=head1 CODE EXAMPLES
+
+Presented with little comment (these will get their own manpages someday)
+here are short code examples illustrating access of various
+types of data structures.
+
+=head1 ARRAYS OF ARRAYS
+X<array of arrays> X<AoA>
+
+=head2 Declaration of an ARRAY OF ARRAYS
+
+ @AoA = (
+ [ "fred", "barney" ],
+ [ "george", "jane", "elroy" ],
+ [ "homer", "marge", "bart" ],
+ );
+
+=head2 Generation of an ARRAY OF ARRAYS
+
+ # reading from file
+ while ( <> ) {
+ push @AoA, [ split ];
+ }
+
+ # calling a function
+ for $i ( 1 .. 10 ) {
+ $AoA[$i] = [ somefunc($i) ];
+ }
+
+ # using temp vars
+ for $i ( 1 .. 10 ) {
+ @tmp = somefunc($i);
+ $AoA[$i] = [ @tmp ];
+ }
+
+ # add to an existing row
+ push @{ $AoA[0] }, "wilma", "betty";
+
+=head2 Access and Printing of an ARRAY OF ARRAYS
+
+ # one element
+ $AoA[0][0] = "Fred";
+
+ # another element
+ $AoA[1][1] =~ s/(\w)/\u$1/;
+
+ # print the whole thing with refs
+ for $aref ( @AoA ) {
+ print "\t [ @$aref ],\n";
+ }
+
+ # print the whole thing with indices
+ for $i ( 0 .. $#AoA ) {
+ print "\t [ @{$AoA[$i]} ],\n";
+ }
+
+ # print the whole thing one at a time
+ for $i ( 0 .. $#AoA ) {
+ for $j ( 0 .. $#{ $AoA[$i] } ) {
+ print "elt $i $j is $AoA[$i][$j]\n";
+ }
+ }
+
+=head1 HASHES OF ARRAYS
+X<hash of arrays> X<HoA>
+
+=head2 Declaration of a HASH OF ARRAYS
+
+ %HoA = (
+ flintstones => [ "fred", "barney" ],
+ jetsons => [ "george", "jane", "elroy" ],
+ simpsons => [ "homer", "marge", "bart" ],
+ );
+
+=head2 Generation of a HASH OF ARRAYS
+
+ # reading from file
+ # flintstones: fred barney wilma dino
+ while ( <> ) {
+ next unless s/^(.*?):\s*//;
+ $HoA{$1} = [ split ];
+ }
+
+ # reading from file; more temps
+ # flintstones: fred barney wilma dino
+ while ( $line = <> ) {
+ ($who, $rest) = split /:\s*/, $line, 2;
+ @fields = split ' ', $rest;
+ $HoA{$who} = [ @fields ];
+ }
+
+ # calling a function that returns a list
+ for $group ( "simpsons", "jetsons", "flintstones" ) {
+ $HoA{$group} = [ get_family($group) ];
+ }
+
+ # likewise, but using temps
+ for $group ( "simpsons", "jetsons", "flintstones" ) {
+ @members = get_family($group);
+ $HoA{$group} = [ @members ];
+ }
+
+ # append new members to an existing family
+ push @{ $HoA{"flintstones"} }, "wilma", "betty";
+
+=head2 Access and Printing of a HASH OF ARRAYS
+
+ # one element
+ $HoA{flintstones}[0] = "Fred";
+
+ # another element
+ $HoA{simpsons}[1] =~ s/(\w)/\u$1/;
+
+ # print the whole thing
+ foreach $family ( keys %HoA ) {
+ print "$family: @{ $HoA{$family} }\n"
+ }
+
+ # print the whole thing with indices
+ foreach $family ( keys %HoA ) {
+ print "family: ";
+ foreach $i ( 0 .. $#{ $HoA{$family} } ) {
+ print " $i = $HoA{$family}[$i]";
+ }
+ print "\n";
+ }
+
+ # print the whole thing sorted by number of members
+ foreach $family ( sort { @{$HoA{$b}} <=> @{$HoA{$a}} } keys %HoA ) {
+ print "$family: @{ $HoA{$family} }\n"
+ }
+
+ # print the whole thing sorted by number of members and name
+ foreach $family ( sort {
+ @{$HoA{$b}} <=> @{$HoA{$a}}
+ ||
+ $a cmp $b
+ } keys %HoA )
+ {
+ print "$family: ", join(", ", sort @{ $HoA{$family} }), "\n";
+ }
+
+=head1 ARRAYS OF HASHES
+X<array of hashes> X<AoH>
+
+=head2 Declaration of an ARRAY OF HASHES
+
+ @AoH = (
+ {
+ Lead => "fred",
+ Friend => "barney",
+ },
+ {
+ Lead => "george",
+ Wife => "jane",
+ Son => "elroy",
+ },
+ {
+ Lead => "homer",
+ Wife => "marge",
+ Son => "bart",
+ }
+ );
+
+=head2 Generation of an ARRAY OF HASHES
+
+ # reading from file
+ # format: LEAD=fred FRIEND=barney
+ while ( <> ) {
+ $rec = {};
+ for $field ( split ) {
+ ($key, $value) = split /=/, $field;
+ $rec->{$key} = $value;
+ }
+ push @AoH, $rec;
+ }
+
+
+ # reading from file
+ # format: LEAD=fred FRIEND=barney
+ # no temp
+ while ( <> ) {
+ push @AoH, { split /[\s+=]/ };
+ }
+
+ # calling a function that returns a key/value pair list, like
+ # "lead","fred","daughter","pebbles"
+ while ( %fields = getnextpairset() ) {
+ push @AoH, { %fields };
+ }
+
+ # likewise, but using no temp vars
+ while (<>) {
+ push @AoH, { parsepairs($_) };
+ }
+
+ # add key/value to an element
+ $AoH[0]{pet} = "dino";
+ $AoH[2]{pet} = "santa's little helper";
+
+=head2 Access and Printing of an ARRAY OF HASHES
+
+ # one element
+ $AoH[0]{lead} = "fred";
+
+ # another element
+ $AoH[1]{lead} =~ s/(\w)/\u$1/;
+
+ # print the whole thing with refs
+ for $href ( @AoH ) {
+ print "{ ";
+ for $role ( keys %$href ) {
+ print "$role=$href->{$role} ";
+ }
+ print "}\n";
+ }
+
+ # print the whole thing with indices
+ for $i ( 0 .. $#AoH ) {
+ print "$i is { ";
+ for $role ( keys %{ $AoH[$i] } ) {
+ print "$role=$AoH[$i]{$role} ";
+ }
+ print "}\n";
+ }
+
+ # print the whole thing one at a time
+ for $i ( 0 .. $#AoH ) {
+ for $role ( keys %{ $AoH[$i] } ) {
+ print "elt $i $role is $AoH[$i]{$role}\n";
+ }
+ }
+
+=head1 HASHES OF HASHES
+X<hash of hashes> X<HoH>
+
+=head2 Declaration of a HASH OF HASHES
+
+ %HoH = (
+ flintstones => {
+ lead => "fred",
+ pal => "barney",
+ },
+ jetsons => {
+ lead => "george",
+ wife => "jane",
+ "his boy" => "elroy",
+ },
+ simpsons => {
+ lead => "homer",
+ wife => "marge",
+ kid => "bart",
+ },
+ );
+
+=head2 Generation of a HASH OF HASHES
+
+ # reading from file
+ # flintstones: lead=fred pal=barney wife=wilma pet=dino
+ while ( <> ) {
+ next unless s/^(.*?):\s*//;
+ $who = $1;
+ for $field ( split ) {
+ ($key, $value) = split /=/, $field;
+ $HoH{$who}{$key} = $value;
+ }
+
+
+ # reading from file; more temps
+ while ( <> ) {
+ next unless s/^(.*?):\s*//;
+ $who = $1;
+ $rec = {};
+ $HoH{$who} = $rec;
+ for $field ( split ) {
+ ($key, $value) = split /=/, $field;
+ $rec->{$key} = $value;
+ }
+ }
+
+ # calling a function that returns a key,value hash
+ for $group ( "simpsons", "jetsons", "flintstones" ) {
+ $HoH{$group} = { get_family($group) };
+ }
+
+ # likewise, but using temps
+ for $group ( "simpsons", "jetsons", "flintstones" ) {
+ %members = get_family($group);
+ $HoH{$group} = { %members };
+ }
+
+ # append new members to an existing family
+ %new_folks = (
+ wife => "wilma",
+ pet => "dino",
+ );
+
+ for $what (keys %new_folks) {
+ $HoH{flintstones}{$what} = $new_folks{$what};
+ }
+
+=head2 Access and Printing of a HASH OF HASHES
+
+ # one element
+ $HoH{flintstones}{wife} = "wilma";
+
+ # another element
+ $HoH{simpsons}{lead} =~ s/(\w)/\u$1/;
+
+ # print the whole thing
+ foreach $family ( keys %HoH ) {
+ print "$family: { ";
+ for $role ( keys %{ $HoH{$family} } ) {
+ print "$role=$HoH{$family}{$role} ";
+ }
+ print "}\n";
+ }
+
+ # print the whole thing somewhat sorted
+ foreach $family ( sort keys %HoH ) {
+ print "$family: { ";
+ for $role ( sort keys %{ $HoH{$family} } ) {
+ print "$role=$HoH{$family}{$role} ";
+ }
+ print "}\n";
+ }
+
+
+ # print the whole thing sorted by number of members
+ foreach $family ( sort { keys %{$HoH{$b}} <=> keys %{$HoH{$a}} } keys %HoH ) {
+ print "$family: { ";
+ for $role ( sort keys %{ $HoH{$family} } ) {
+ print "$role=$HoH{$family}{$role} ";
+ }
+ print "}\n";
+ }
+
+ # establish a sort order (rank) for each role
+ $i = 0;
+ for ( qw(lead wife son daughter pal pet) ) { $rank{$_} = ++$i }
+
+ # now print the whole thing sorted by number of members
+ foreach $family ( sort { keys %{ $HoH{$b} } <=> keys %{ $HoH{$a} } } keys %HoH ) {
+ print "$family: { ";
+ # and print these according to rank order
+ for $role ( sort { $rank{$a} <=> $rank{$b} } keys %{ $HoH{$family} } ) {
+ print "$role=$HoH{$family}{$role} ";
+ }
+ print "}\n";
+ }
+
+
+=head1 MORE ELABORATE RECORDS
+X<record> X<structure> X<struct>
+
+=head2 Declaration of MORE ELABORATE RECORDS
+
+Here's a sample showing how to create and use a record whose fields are of
+many different sorts:
+
+ $rec = {
+ TEXT => $string,
+ SEQUENCE => [ @old_values ],
+ LOOKUP => { %some_table },
+ THATCODE => \&some_function,
+ THISCODE => sub { $_[0] ** $_[1] },
+ HANDLE => \*STDOUT,
+ };
+
+ print $rec->{TEXT};
+
+ print $rec->{SEQUENCE}[0];
+ $last = pop @ { $rec->{SEQUENCE} };
+
+ print $rec->{LOOKUP}{"key"};
+ ($first_k, $first_v) = each %{ $rec->{LOOKUP} };
+
+ $answer = $rec->{THATCODE}->($arg);
+ $answer = $rec->{THISCODE}->($arg1, $arg2);
+
+ # careful of extra block braces on fh ref
+ print { $rec->{HANDLE} } "a string\n";
+
+ use FileHandle;
+ $rec->{HANDLE}->autoflush(1);
+ $rec->{HANDLE}->print(" a string\n");
+
+=head2 Declaration of a HASH OF COMPLEX RECORDS
+
+ %TV = (
+ flintstones => {
+ series => "flintstones",
+ nights => [ qw(monday thursday friday) ],
+ members => [
+ { name => "fred", role => "lead", age => 36, },
+ { name => "wilma", role => "wife", age => 31, },
+ { name => "pebbles", role => "kid", age => 4, },
+ ],
+ },
+
+ jetsons => {
+ series => "jetsons",
+ nights => [ qw(wednesday saturday) ],
+ members => [
+ { name => "george", role => "lead", age => 41, },
+ { name => "jane", role => "wife", age => 39, },
+ { name => "elroy", role => "kid", age => 9, },
+ ],
+ },
+
+ simpsons => {
+ series => "simpsons",
+ nights => [ qw(monday) ],
+ members => [
+ { name => "homer", role => "lead", age => 34, },
+ { name => "marge", role => "wife", age => 37, },
+ { name => "bart", role => "kid", age => 11, },
+ ],
+ },
+ );
+
+=head2 Generation of a HASH OF COMPLEX RECORDS
+
+ # reading from file
+ # this is most easily done by having the file itself be
+ # in the raw data format as shown above. perl is happy
+ # to parse complex data structures if declared as data, so
+ # sometimes it's easiest to do that
+
+ # here's a piece by piece build up
+ $rec = {};
+ $rec->{series} = "flintstones";
+ $rec->{nights} = [ find_days() ];
+
+ @members = ();
+ # assume this file in field=value syntax
+ while (<>) {
+ %fields = split /[\s=]+/;
+ push @members, { %fields };
+ }
+ $rec->{members} = [ @members ];
+
+ # now remember the whole thing
+ $TV{ $rec->{series} } = $rec;
+
+ ###########################################################
+ # now, you might want to make interesting extra fields that
+ # include pointers back into the same data structure so if
+ # change one piece, it changes everywhere, like for example
+ # if you wanted a {kids} field that was a reference
+ # to an array of the kids' records without having duplicate
+ # records and thus update problems.
+ ###########################################################
+ foreach $family (keys %TV) {
+ $rec = $TV{$family}; # temp pointer
+ @kids = ();
+ for $person ( @{ $rec->{members} } ) {
+ if ($person->{role} =~ /kid|son|daughter/) {
+ push @kids, $person;
+ }
+ }
+ # REMEMBER: $rec and $TV{$family} point to same data!!
+ $rec->{kids} = [ @kids ];
+ }
+
+ # you copied the array, but the array itself contains pointers
+ # to uncopied objects. this means that if you make bart get
+ # older via
+
+ $TV{simpsons}{kids}[0]{age}++;
+
+ # then this would also change in
+ print $TV{simpsons}{members}[2]{age};
+
+ # because $TV{simpsons}{kids}[0] and $TV{simpsons}{members}[2]
+ # both point to the same underlying anonymous hash table
+
+ # print the whole thing
+ foreach $family ( keys %TV ) {
+ print "the $family";
+ print " is on during @{ $TV{$family}{nights} }\n";
+ print "its members are:\n";
+ for $who ( @{ $TV{$family}{members} } ) {
+ print " $who->{name} ($who->{role}), age $who->{age}\n";
+ }
+ print "it turns out that $TV{$family}{lead} has ";
+ print scalar ( @{ $TV{$family}{kids} } ), " kids named ";
+ print join (", ", map { $_->{name} } @{ $TV{$family}{kids} } );
+ print "\n";
+ }
+
+=head1 Database Ties
+
+You cannot easily tie a multilevel data structure (such as a hash of
+hashes) to a dbm file. The first problem is that all but GDBM and
+Berkeley DB have size limitations, but beyond that, you also have problems
+with how references are to be represented on disk. One experimental
+module that does partially attempt to address this need is the MLDBM
+module. Check your nearest CPAN site as described in L<perlmodlib> for
+source code to MLDBM.
+
+=head1 SEE ALSO
+
+L<perlref>, L<perllol>, L<perldata>, L<perlobj>
+
+=head1 AUTHOR
+
+Tom Christiansen <F<tchrist@perl.com>>
+
+Last update:
+Wed Oct 23 04:57:50 MET DST 1996
diff --git a/Master/tlpkg/tlperl/lib/pods/perlebcdic.pod b/Master/tlpkg/tlperl/lib/pods/perlebcdic.pod
new file mode 100644
index 00000000000..f17891237a0
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlebcdic.pod
@@ -0,0 +1,1424 @@
+=head1 NAME
+
+perlebcdic - Considerations for running Perl on EBCDIC platforms
+
+=head1 DESCRIPTION
+
+An exploration of some of the issues facing Perl programmers
+on EBCDIC based computers. We do not cover localization,
+internationalization, or multi byte character set issues other
+than some discussion of UTF-8 and UTF-EBCDIC.
+
+Portions that are still incomplete are marked with XXX.
+
+Perl used to work on EBCDIC machines, but there are now areas of the code where
+it doesn't. If you want to use Perl on an EBCDIC machine, please let us know
+by sending mail to perlbug@perl.org
+
+=head1 COMMON CHARACTER CODE SETS
+
+=head2 ASCII
+
+The American Standard Code for Information Interchange (ASCII or US-ASCII) is a
+set of
+integers running from 0 to 127 (decimal) that imply character
+interpretation by the display and other systems of computers.
+The range 0..127 can be covered by setting the bits in a 7-bit binary
+digit, hence the set is sometimes referred to as a "7-bit ASCII".
+ASCII was described by the American National Standards Institute
+document ANSI X3.4-1986. It was also described by ISO 646:1991
+(with localization for currency symbols). The full ASCII set is
+given in the table below as the first 128 elements. Languages that
+can be written adequately with the characters in ASCII include
+English, Hawaiian, Indonesian, Swahili and some Native American
+languages.
+
+There are many character sets that extend the range of integers
+from 0..2**7-1 up to 2**8-1, or 8 bit bytes (octets if you prefer).
+One common one is the ISO 8859-1 character set.
+
+=head2 ISO 8859
+
+The ISO 8859-$n are a collection of character code sets from the
+International Organization for Standardization (ISO) each of which
+adds characters to the ASCII set that are typically found in European
+languages many of which are based on the Roman, or Latin, alphabet.
+
+=head2 Latin 1 (ISO 8859-1)
+
+A particular 8-bit extension to ASCII that includes grave and acute
+accented Latin characters. Languages that can employ ISO 8859-1
+include all the languages covered by ASCII as well as Afrikaans,
+Albanian, Basque, Catalan, Danish, Faroese, Finnish, Norwegian,
+Portuguese, Spanish, and Swedish. Dutch is covered albeit without
+the ij ligature. French is covered too but without the oe ligature.
+German can use ISO 8859-1 but must do so without German-style
+quotation marks. This set is based on Western European extensions
+to ASCII and is commonly encountered in world wide web work.
+In IBM character code set identification terminology ISO 8859-1 is
+also known as CCSID 819 (or sometimes 0819 or even 00819).
+
+=head2 EBCDIC
+
+The Extended Binary Coded Decimal Interchange Code refers to a
+large collection of single and multi byte coded character sets that are
+different from ASCII or ISO 8859-1 and are all slightly different from each
+other; they typically run on host computers. The EBCDIC encodings derive from
+8 bit byte extensions of Hollerith punched card encodings. The layout on the
+cards was such that high bits were set for the upper and lower case alphabet
+characters [a-z] and [A-Z], but there were gaps within each Latin alphabet
+range.
+
+Some IBM EBCDIC character sets may be known by character code set
+identification numbers (CCSID numbers) or code page numbers.
+
+Perl can be compiled on platforms that run any of three commonly used EBCDIC
+character sets, listed below.
+
+=head2 The 13 variant characters
+
+Among IBM EBCDIC character code sets there are 13 characters that
+are often mapped to different integer values. Those characters
+are known as the 13 "variant" characters and are:
+
+ \ [ ] { } ^ ~ ! # | $ @ `
+
+When Perl is compiled for a platform, it looks at some of these characters to
+guess which EBCDIC character set the platform uses, and adapts itself
+accordingly to that platform. If the platform uses a character set that is not
+one of the three Perl knows about, Perl will either fail to compile, or
+mistakenly and silently choose one of the three.
+They are:
+
+=head2 0037
+
+Character code set ID 0037 is a mapping of the ASCII plus Latin-1
+characters (i.e. ISO 8859-1) to an EBCDIC set. 0037 is used
+in North American English locales on the OS/400 operating system
+that runs on AS/400 computers. CCSID 0037 differs from ISO 8859-1
+in 237 places, in other words they agree on only 19 code point values.
+
+=head2 1047
+
+Character code set ID 1047 is also a mapping of the ASCII plus
+Latin-1 characters (i.e. ISO 8859-1) to an EBCDIC set. 1047 is
+used under Unix System Services for OS/390 or z/OS, and OpenEdition
+for VM/ESA. CCSID 1047 differs from CCSID 0037 in eight places.
+
+=head2 POSIX-BC
+
+The EBCDIC code page in use on Siemens' BS2000 system is distinct from
+1047 and 0037. It is identified below as the POSIX-BC set.
+
+=head2 Unicode code points versus EBCDIC code points
+
+In Unicode terminology a I<code point> is the number assigned to a
+character: for example, in EBCDIC the character "A" is usually assigned
+the number 193. In Unicode the character "A" is assigned the number 65.
+This causes a problem with the semantics of the pack/unpack "U", which
+are supposed to pack Unicode code points to characters and back to numbers.
+The problem is: which code points to use for code points less than 256?
+(for 256 and over there's no problem: Unicode code points are used)
+In EBCDIC, for the low 256 the EBCDIC code points are used. This
+means that the equivalences
+
+ pack("U", ord($character)) eq $character
+ unpack("U", $character) == ord $character
+
+will hold. (If Unicode code points were applied consistently over
+all the possible code points, pack("U",ord("A")) would in EBCDIC
+equal I<A with acute> or chr(101), and unpack("U", "A") would equal
+65, or I<non-breaking space>, not 193, or ord "A".)
+
+=head2 Remaining Perl Unicode problems in EBCDIC
+
+=over 4
+
+=item *
+
+Many of the remaining problems seem to be related to case-insensitive matching
+
+=item *
+
+The extensions Unicode::Collate and Unicode::Normalized are not
+supported under EBCDIC, likewise for the encoding pragma.
+
+=back
+
+=head2 Unicode and UTF
+
+UTF stands for C<Unicode Transformation Format>.
+UTF-8 is an encoding of Unicode into a sequence of 8-bit byte chunks, based on
+ASCII and Latin-1.
+The length of a sequence required to represent a Unicode code point
+depends on the ordinal number of that code point,
+with larger numbers requiring more bytes.
+UTF-EBCDIC is like UTF-8, but based on EBCDIC.
+
+You may see the term C<invariant> character or code point.
+This simply means that the character has the same numeric
+value when encoded as when not.
+(Note that this is a very different concept from L</The 13 variant characters>
+mentioned above.)
+For example, the ordinal value of 'A' is 193 in most EBCDIC code pages,
+and also is 193 when encoded in UTF-EBCDIC.
+All variant code points occupy at least two bytes when encoded.
+In UTF-8, the code points corresponding to the lowest 128
+ordinal numbers (0 - 127: the ASCII characters) are invariant.
+In UTF-EBCDIC, there are 160 invariant characters.
+(If you care, the EBCDIC invariants are those characters
+which have ASCII equivalents, plus those that correspond to
+the C1 controls (80..9f on ASCII platforms).)
+
+A string encoded in UTF-EBCDIC may be longer (but never shorter) than
+one encoded in UTF-8.
+
+=head2 Using Encode
+
+Starting from Perl 5.8 you can use the standard new module Encode
+to translate from EBCDIC to Latin-1 code points.
+Encode knows about more EBCDIC character sets than Perl can currently
+be compiled to run on.
+
+ use Encode 'from_to';
+
+ my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
+
+ # $a is in EBCDIC code points
+ from_to($a, $ebcdic{ord '^'}, 'latin1');
+ # $a is ISO 8859-1 code points
+
+and from Latin-1 code points to EBCDIC code points
+
+ use Encode 'from_to';
+
+ my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
+
+ # $a is ISO 8859-1 code points
+ from_to($a, 'latin1', $ebcdic{ord '^'});
+ # $a is in EBCDIC code points
+
+For doing I/O it is suggested that you use the autotranslating features
+of PerlIO, see L<perluniintro>.
+
+Since version 5.8 Perl uses the new PerlIO I/O library. This enables
+you to use different encodings per IO channel. For example you may use
+
+ use Encode;
+ open($f, ">:encoding(ascii)", "test.ascii");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(cp37)", "test.ebcdic");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(latin1)", "test.latin1");
+ print $f "Hello World!\n";
+ open($f, ">:encoding(utf8)", "test.utf8");
+ print $f "Hello World!\n";
+
+to get four files containing "Hello World!\n" in ASCII, CP 0037 EBCDIC,
+ISO 8859-1 (Latin-1) (in this example identical to ASCII since only ASCII
+characters were printed), and
+UTF-EBCDIC (in this example identical to normal EBCDIC since only characters
+that don't differ between EBCDIC and UTF-EBCDIC were printed). See the
+documentation of Encode::PerlIO for details.
+
+As the PerlIO layer uses raw IO (bytes) internally, all this totally
+ignores things like the type of your filesystem (ASCII or EBCDIC).
+
+=head1 SINGLE OCTET TABLES
+
+The following tables list the ASCII and Latin 1 ordered sets including
+the subsets: C0 controls (0..31), ASCII graphics (32..7e), delete (7f),
+C1 controls (80..9f), and Latin-1 (a.k.a. ISO 8859-1) (a0..ff). In the
+table non-printing control character names as well as the Latin 1
+extensions to ASCII have been labelled with character names roughly
+corresponding to I<The Unicode Standard, Version 3.0> albeit with
+substitutions such as s/LATIN// and s/VULGAR// in all cases,
+s/CAPITAL LETTER// in some cases, and s/SMALL LETTER ([A-Z])/\l$1/
+in some other cases. The "names" of the controls listed here are
+the Unicode Version 1 names, except for the few that don't have names, in which
+case the names in the Wikipedia article were used
+(L<http://en.wikipedia.org/wiki/C0_and_C1_control_codes>.
+The differences between the 0037 and 1047 sets are
+flagged with ***. The differences between the 1047 and POSIX-BC sets
+are flagged with ###. All ord() numbers listed are decimal. If you
+would rather see this table listing octal values then run the table
+(that is, the pod version of this document since this recipe may not
+work with a pod2_other_format translation) through:
+
+=over 4
+
+=item recipe 0
+
+=back
+
+ perl -ne 'if(/(.{43})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
+ -e '{printf("%s%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
+
+If you want to retain the UTF-x code points then in script form you
+might want to write:
+
+=over 4
+
+=item recipe 1
+
+=back
+
+ open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
+ while (<FH>) {
+ if (/(.{43})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/) {
+ if ($7 ne '' && $9 ne '') {
+ printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%-3o.%o\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
+ }
+ elsif ($7 ne '') {
+ printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%o\n",$1,$2,$3,$4,$5,$6,$7,$8);
+ }
+ else {
+ printf("%s%-9o%-9o%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5,$6,$8);
+ }
+ }
+ }
+
+If you would rather see this table listing hexadecimal values then
+run the table through:
+
+=over 4
+
+=item recipe 2
+
+=back
+
+ perl -ne 'if(/(.{43})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
+ -e '{printf("%s%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
+
+Or, in order to retain the UTF-x code points in hexadecimal:
+
+=over 4
+
+=item recipe 3
+
+=back
+
+ open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
+ while (<FH>) {
+ if (/(.{43})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/) {
+ if ($7 ne '' && $9 ne '') {
+ printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%-2X.%X\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
+ }
+ elsif ($7 ne '') {
+ printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%X\n",$1,$2,$3,$4,$5,$6,$7,$8);
+ }
+ else {
+ printf("%s%-9X%-9X%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5,$6,$8);
+ }
+ }
+ }
+
+
+ ISO 8859-1 CCSID CCSID CCSID 1047
+ chr CCSID 0819 0037 1047 POSIX-BC UTF-8 UTF-EBCDIC
+ ----------------------------------------------------------------------------------------------
+ <NULL> 0 0 0 0 0 0
+ <START OF HEADING> 1 1 1 1 1 1
+ <START OF TEXT> 2 2 2 2 2 2
+ <END OF TEXT> 3 3 3 3 3 3
+ <END OF TRANSMISSION> 4 55 55 55 4 55
+ <ENQUIRY> 5 45 45 45 5 45
+ <ACKNOWLEDGE> 6 46 46 46 6 46
+ <BELL> 7 47 47 47 7 47
+ <BACKSPACE> 8 22 22 22 8 22
+ <HORIZONTAL TABULATION> 9 5 5 5 9 5
+ <LINE FEED> 10 37 21 21 10 21 ***
+ <VERTICAL TABULATION> 11 11 11 11 11 11
+ <FORM FEED> 12 12 12 12 12 12
+ <CARRIAGE RETURN> 13 13 13 13 13 13
+ <SHIFT OUT> 14 14 14 14 14 14
+ <SHIFT IN> 15 15 15 15 15 15
+ <DATA LINK ESCAPE> 16 16 16 16 16 16
+ <DEVICE CONTROL ONE> 17 17 17 17 17 17
+ <DEVICE CONTROL TWO> 18 18 18 18 18 18
+ <DEVICE CONTROL THREE> 19 19 19 19 19 19
+ <DEVICE CONTROL FOUR> 20 60 60 60 20 60
+ <NEGATIVE ACKNOWLEDGE> 21 61 61 61 21 61
+ <SYNCHRONOUS IDLE> 22 50 50 50 22 50
+ <END OF TRANSMISSION BLOCK> 23 38 38 38 23 38
+ <CANCEL> 24 24 24 24 24 24
+ <END OF MEDIUM> 25 25 25 25 25 25
+ <SUBSTITUTE> 26 63 63 63 26 63
+ <ESCAPE> 27 39 39 39 27 39
+ <FILE SEPARATOR> 28 28 28 28 28 28
+ <GROUP SEPARATOR> 29 29 29 29 29 29
+ <RECORD SEPARATOR> 30 30 30 30 30 30
+ <UNIT SEPARATOR> 31 31 31 31 31 31
+ <SPACE> 32 64 64 64 32 64
+ ! 33 90 90 90 33 90
+ " 34 127 127 127 34 127
+ # 35 123 123 123 35 123
+ $ 36 91 91 91 36 91
+ % 37 108 108 108 37 108
+ & 38 80 80 80 38 80
+ ' 39 125 125 125 39 125
+ ( 40 77 77 77 40 77
+ ) 41 93 93 93 41 93
+ * 42 92 92 92 42 92
+ + 43 78 78 78 43 78
+ , 44 107 107 107 44 107
+ - 45 96 96 96 45 96
+ . 46 75 75 75 46 75
+ / 47 97 97 97 47 97
+ 0 48 240 240 240 48 240
+ 1 49 241 241 241 49 241
+ 2 50 242 242 242 50 242
+ 3 51 243 243 243 51 243
+ 4 52 244 244 244 52 244
+ 5 53 245 245 245 53 245
+ 6 54 246 246 246 54 246
+ 7 55 247 247 247 55 247
+ 8 56 248 248 248 56 248
+ 9 57 249 249 249 57 249
+ : 58 122 122 122 58 122
+ ; 59 94 94 94 59 94
+ < 60 76 76 76 60 76
+ = 61 126 126 126 61 126
+ > 62 110 110 110 62 110
+ ? 63 111 111 111 63 111
+ @ 64 124 124 124 64 124
+ A 65 193 193 193 65 193
+ B 66 194 194 194 66 194
+ C 67 195 195 195 67 195
+ D 68 196 196 196 68 196
+ E 69 197 197 197 69 197
+ F 70 198 198 198 70 198
+ G 71 199 199 199 71 199
+ H 72 200 200 200 72 200
+ I 73 201 201 201 73 201
+ J 74 209 209 209 74 209
+ K 75 210 210 210 75 210
+ L 76 211 211 211 76 211
+ M 77 212 212 212 77 212
+ N 78 213 213 213 78 213
+ O 79 214 214 214 79 214
+ P 80 215 215 215 80 215
+ Q 81 216 216 216 81 216
+ R 82 217 217 217 82 217
+ S 83 226 226 226 83 226
+ T 84 227 227 227 84 227
+ U 85 228 228 228 85 228
+ V 86 229 229 229 86 229
+ W 87 230 230 230 87 230
+ X 88 231 231 231 88 231
+ Y 89 232 232 232 89 232
+ Z 90 233 233 233 90 233
+ [ 91 186 173 187 91 173 *** ###
+ \ 92 224 224 188 92 224 ###
+ ] 93 187 189 189 93 189 ***
+ ^ 94 176 95 106 94 95 *** ###
+ _ 95 109 109 109 95 109
+ ` 96 121 121 74 96 121 ###
+ a 97 129 129 129 97 129
+ b 98 130 130 130 98 130
+ c 99 131 131 131 99 131
+ d 100 132 132 132 100 132
+ e 101 133 133 133 101 133
+ f 102 134 134 134 102 134
+ g 103 135 135 135 103 135
+ h 104 136 136 136 104 136
+ i 105 137 137 137 105 137
+ j 106 145 145 145 106 145
+ k 107 146 146 146 107 146
+ l 108 147 147 147 108 147
+ m 109 148 148 148 109 148
+ n 110 149 149 149 110 149
+ o 111 150 150 150 111 150
+ p 112 151 151 151 112 151
+ q 113 152 152 152 113 152
+ r 114 153 153 153 114 153
+ s 115 162 162 162 115 162
+ t 116 163 163 163 116 163
+ u 117 164 164 164 117 164
+ v 118 165 165 165 118 165
+ w 119 166 166 166 119 166
+ x 120 167 167 167 120 167
+ y 121 168 168 168 121 168
+ z 122 169 169 169 122 169
+ { 123 192 192 251 123 192 ###
+ | 124 79 79 79 124 79
+ } 125 208 208 253 125 208 ###
+ ~ 126 161 161 255 126 161 ###
+ <DELETE> 127 7 7 7 127 7
+ <PADDING CHARACTER> 128 32 32 32 194.128 32
+ <HIGH OCTET PRESET> 129 33 33 33 194.129 33
+ <BREAK PERMITTED HERE> 130 34 34 34 194.130 34
+ <NO BREAK HERE> 131 35 35 35 194.131 35
+ <INDEX> 132 36 36 36 194.132 36
+ <NEXT LINE> 133 21 37 37 194.133 37 ***
+ <START OF SELECTED AREA> 134 6 6 6 194.134 6
+ <END OF SELECTED AREA> 135 23 23 23 194.135 23
+ <CHARACTER TABULATION SET> 136 40 40 40 194.136 40
+ <CHARACTER TABULATION WITH JUSTIFICATION> 137 41 41 41 194.137 41
+ <LINE TABULATION SET> 138 42 42 42 194.138 42
+ <PARTIAL LINE FORWARD> 139 43 43 43 194.139 43
+ <PARTIAL LINE BACKWARD> 140 44 44 44 194.140 44
+ <REVERSE LINE FEED> 141 9 9 9 194.141 9
+ <SINGLE SHIFT TWO> 142 10 10 10 194.142 10
+ <SINGLE SHIFT THREE> 143 27 27 27 194.143 27
+ <DEVICE CONTROL STRING> 144 48 48 48 194.144 48
+ <PRIVATE USE ONE> 145 49 49 49 194.145 49
+ <PRIVATE USE TWO> 146 26 26 26 194.146 26
+ <SET TRANSMIT STATE> 147 51 51 51 194.147 51
+ <CANCEL CHARACTER> 148 52 52 52 194.148 52
+ <MESSAGE WAITING> 149 53 53 53 194.149 53
+ <START OF GUARDED AREA> 150 54 54 54 194.150 54
+ <END OF GUARDED AREA> 151 8 8 8 194.151 8
+ <START OF STRING> 152 56 56 56 194.152 56
+ <SINGLE GRAPHIC CHARACTER INTRODUCER> 153 57 57 57 194.153 57
+ <SINGLE CHARACTER INTRODUCER> 154 58 58 58 194.154 58
+ <CONTROL SEQUENCE INTRODUCER> 155 59 59 59 194.155 59
+ <STRING TERMINATOR> 156 4 4 4 194.156 4
+ <OPERATING SYSTEM COMMAND> 157 20 20 20 194.157 20
+ <PRIVACY MESSAGE> 158 62 62 62 194.158 62
+ <APPLICATION PROGRAM COMMAND> 159 255 255 95 194.159 255 ###
+ <NON-BREAKING SPACE> 160 65 65 65 194.160 128.65
+ <INVERTED EXCLAMATION MARK> 161 170 170 170 194.161 128.66
+ <CENT SIGN> 162 74 74 176 194.162 128.67 ###
+ <POUND SIGN> 163 177 177 177 194.163 128.68
+ <CURRENCY SIGN> 164 159 159 159 194.164 128.69
+ <YEN SIGN> 165 178 178 178 194.165 128.70
+ <BROKEN BAR> 166 106 106 208 194.166 128.71 ###
+ <SECTION SIGN> 167 181 181 181 194.167 128.72
+ <DIAERESIS> 168 189 187 121 194.168 128.73 *** ###
+ <COPYRIGHT SIGN> 169 180 180 180 194.169 128.74
+ <FEMININE ORDINAL INDICATOR> 170 154 154 154 194.170 128.81
+ <LEFT POINTING GUILLEMET> 171 138 138 138 194.171 128.82
+ <NOT SIGN> 172 95 176 186 194.172 128.83 *** ###
+ <SOFT HYPHEN> 173 202 202 202 194.173 128.84
+ <REGISTERED TRADE MARK SIGN> 174 175 175 175 194.174 128.85
+ <MACRON> 175 188 188 161 194.175 128.86 ###
+ <DEGREE SIGN> 176 144 144 144 194.176 128.87
+ <PLUS-OR-MINUS SIGN> 177 143 143 143 194.177 128.88
+ <SUPERSCRIPT TWO> 178 234 234 234 194.178 128.89
+ <SUPERSCRIPT THREE> 179 250 250 250 194.179 128.98
+ <ACUTE ACCENT> 180 190 190 190 194.180 128.99
+ <MICRO SIGN> 181 160 160 160 194.181 128.100
+ <PARAGRAPH SIGN> 182 182 182 182 194.182 128.101
+ <MIDDLE DOT> 183 179 179 179 194.183 128.102
+ <CEDILLA> 184 157 157 157 194.184 128.103
+ <SUPERSCRIPT ONE> 185 218 218 218 194.185 128.104
+ <MASC. ORDINAL INDICATOR> 186 155 155 155 194.186 128.105
+ <RIGHT POINTING GUILLEMET> 187 139 139 139 194.187 128.106
+ <FRACTION ONE QUARTER> 188 183 183 183 194.188 128.112
+ <FRACTION ONE HALF> 189 184 184 184 194.189 128.113
+ <FRACTION THREE QUARTERS> 190 185 185 185 194.190 128.114
+ <INVERTED QUESTION MARK> 191 171 171 171 194.191 128.115
+ <A WITH GRAVE> 192 100 100 100 195.128 138.65
+ <A WITH ACUTE> 193 101 101 101 195.129 138.66
+ <A WITH CIRCUMFLEX> 194 98 98 98 195.130 138.67
+ <A WITH TILDE> 195 102 102 102 195.131 138.68
+ <A WITH DIAERESIS> 196 99 99 99 195.132 138.69
+ <A WITH RING ABOVE> 197 103 103 103 195.133 138.70
+ <CAPITAL LIGATURE AE> 198 158 158 158 195.134 138.71
+ <C WITH CEDILLA> 199 104 104 104 195.135 138.72
+ <E WITH GRAVE> 200 116 116 116 195.136 138.73
+ <E WITH ACUTE> 201 113 113 113 195.137 138.74
+ <E WITH CIRCUMFLEX> 202 114 114 114 195.138 138.81
+ <E WITH DIAERESIS> 203 115 115 115 195.139 138.82
+ <I WITH GRAVE> 204 120 120 120 195.140 138.83
+ <I WITH ACUTE> 205 117 117 117 195.141 138.84
+ <I WITH CIRCUMFLEX> 206 118 118 118 195.142 138.85
+ <I WITH DIAERESIS> 207 119 119 119 195.143 138.86
+ <CAPITAL LETTER ETH> 208 172 172 172 195.144 138.87
+ <N WITH TILDE> 209 105 105 105 195.145 138.88
+ <O WITH GRAVE> 210 237 237 237 195.146 138.89
+ <O WITH ACUTE> 211 238 238 238 195.147 138.98
+ <O WITH CIRCUMFLEX> 212 235 235 235 195.148 138.99
+ <O WITH TILDE> 213 239 239 239 195.149 138.100
+ <O WITH DIAERESIS> 214 236 236 236 195.150 138.101
+ <MULTIPLICATION SIGN> 215 191 191 191 195.151 138.102
+ <O WITH STROKE> 216 128 128 128 195.152 138.103
+ <U WITH GRAVE> 217 253 253 224 195.153 138.104 ###
+ <U WITH ACUTE> 218 254 254 254 195.154 138.105
+ <U WITH CIRCUMFLEX> 219 251 251 221 195.155 138.106 ###
+ <U WITH DIAERESIS> 220 252 252 252 195.156 138.112
+ <Y WITH ACUTE> 221 173 186 173 195.157 138.113 *** ###
+ <CAPITAL LETTER THORN> 222 174 174 174 195.158 138.114
+ <SMALL LETTER SHARP S> 223 89 89 89 195.159 138.115
+ <a WITH GRAVE> 224 68 68 68 195.160 139.65
+ <a WITH ACUTE> 225 69 69 69 195.161 139.66
+ <a WITH CIRCUMFLEX> 226 66 66 66 195.162 139.67
+ <a WITH TILDE> 227 70 70 70 195.163 139.68
+ <a WITH DIAERESIS> 228 67 67 67 195.164 139.69
+ <a WITH RING ABOVE> 229 71 71 71 195.165 139.70
+ <SMALL LIGATURE ae> 230 156 156 156 195.166 139.71
+ <c WITH CEDILLA> 231 72 72 72 195.167 139.72
+ <e WITH GRAVE> 232 84 84 84 195.168 139.73
+ <e WITH ACUTE> 233 81 81 81 195.169 139.74
+ <e WITH CIRCUMFLEX> 234 82 82 82 195.170 139.81
+ <e WITH DIAERESIS> 235 83 83 83 195.171 139.82
+ <i WITH GRAVE> 236 88 88 88 195.172 139.83
+ <i WITH ACUTE> 237 85 85 85 195.173 139.84
+ <i WITH CIRCUMFLEX> 238 86 86 86 195.174 139.85
+ <i WITH DIAERESIS> 239 87 87 87 195.175 139.86
+ <SMALL LETTER eth> 240 140 140 140 195.176 139.87
+ <n WITH TILDE> 241 73 73 73 195.177 139.88
+ <o WITH GRAVE> 242 205 205 205 195.178 139.89
+ <o WITH ACUTE> 243 206 206 206 195.179 139.98
+ <o WITH CIRCUMFLEX> 244 203 203 203 195.180 139.99
+ <o WITH TILDE> 245 207 207 207 195.181 139.100
+ <o WITH DIAERESIS> 246 204 204 204 195.182 139.101
+ <DIVISION SIGN> 247 225 225 225 195.183 139.102
+ <o WITH STROKE> 248 112 112 112 195.184 139.103
+ <u WITH GRAVE> 249 221 221 192 195.185 139.104 ###
+ <u WITH ACUTE> 250 222 222 222 195.186 139.105
+ <u WITH CIRCUMFLEX> 251 219 219 219 195.187 139.106
+ <u WITH DIAERESIS> 252 220 220 220 195.188 139.112
+ <y WITH ACUTE> 253 141 141 141 195.189 139.113
+ <SMALL LETTER thorn> 254 142 142 142 195.190 139.114
+ <y WITH DIAERESIS> 255 223 223 223 195.191 139.115
+
+If you would rather see the above table in CCSID 0037 order rather than
+ASCII + Latin-1 order then run the table through:
+
+=over 4
+
+=item recipe 4
+
+=back
+
+ perl -ne 'if(/.{43}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
+ -e '{push(@l,$_)}' \
+ -e 'END{print map{$_->[0]}' \
+ -e ' sort{$a->[1] <=> $b->[1]}' \
+ -e ' map{[$_,substr($_,52,3)]}@l;}' perlebcdic.pod
+
+If you would rather see it in CCSID 1047 order then change the number
+52 in the last line to 61, like this:
+
+=over 4
+
+=item recipe 5
+
+=back
+
+ perl -ne 'if(/.{43}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
+ -e '{push(@l,$_)}' \
+ -e 'END{print map{$_->[0]}' \
+ -e ' sort{$a->[1] <=> $b->[1]}' \
+ -e ' map{[$_,substr($_,61,3)]}@l;}' perlebcdic.pod
+
+If you would rather see it in POSIX-BC order then change the number
+61 in the last line to 70, like this:
+
+=over 4
+
+=item recipe 6
+
+=back
+
+ perl -ne 'if(/.{43}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
+ -e '{push(@l,$_)}' \
+ -e 'END{print map{$_->[0]}' \
+ -e ' sort{$a->[1] <=> $b->[1]}' \
+ -e ' map{[$_,substr($_,70,3)]}@l;}' perlebcdic.pod
+
+
+=head1 IDENTIFYING CHARACTER CODE SETS
+
+To determine the character set you are running under from perl one
+could use the return value of ord() or chr() to test one or more
+character values. For example:
+
+ $is_ascii = "A" eq chr(65);
+ $is_ebcdic = "A" eq chr(193);
+
+Also, "\t" is a C<HORIZONTAL TABULATION> character so that:
+
+ $is_ascii = ord("\t") == 9;
+ $is_ebcdic = ord("\t") == 5;
+
+To distinguish EBCDIC code pages try looking at one or more of
+the characters that differ between them. For example:
+
+ $is_ebcdic_37 = "\n" eq chr(37);
+ $is_ebcdic_1047 = "\n" eq chr(21);
+
+Or better still choose a character that is uniquely encoded in any
+of the code sets, e.g.:
+
+ $is_ascii = ord('[') == 91;
+ $is_ebcdic_37 = ord('[') == 186;
+ $is_ebcdic_1047 = ord('[') == 173;
+ $is_ebcdic_POSIX_BC = ord('[') == 187;
+
+However, it would be unwise to write tests such as:
+
+ $is_ascii = "\r" ne chr(13); # WRONG
+ $is_ascii = "\n" ne chr(10); # ILL ADVISED
+
+Obviously the first of these will fail to distinguish most ASCII platforms
+from either a CCSID 0037, a 1047, or a POSIX-BC EBCDIC platform since "\r" eq
+chr(13) under all of those coded character sets. But note too that
+because "\n" is chr(13) and "\r" is chr(10) on the MacIntosh (which is an
+ASCII platform) the second C<$is_ascii> test will lead to trouble there.
+
+To determine whether or not perl was built under an EBCDIC
+code page you can use the Config module like so:
+
+ use Config;
+ $is_ebcdic = $Config{'ebcdic'} eq 'define';
+
+=head1 CONVERSIONS
+
+=head2 tr///
+
+In order to convert a string of characters from one character set to
+another a simple list of numbers, such as in the right columns in the
+above table, along with perl's tr/// operator is all that is needed.
+The data in the table are in ASCII order hence the EBCDIC columns
+provide easy to use ASCII to EBCDIC operations that are also easily
+reversed.
+
+For example, to convert ASCII to code page 037 take the output of the second
+column from the output of recipe 0 (modified to add \\ characters) and use
+it in tr/// like so:
+
+ $cp_037 =
+ '\000\001\002\003\234\011\206\177\227\215\216\013\014\015\016\017' .
+ '\020\021\022\023\235\205\010\207\030\031\222\217\034\035\036\037' .
+ '\200\201\202\203\204\012\027\033\210\211\212\213\214\005\006\007' .
+ '\220\221\026\223\224\225\226\004\230\231\232\233\024\025\236\032' .
+ '\040\240\342\344\340\341\343\345\347\361\242\056\074\050\053\174' .
+ '\046\351\352\353\350\355\356\357\354\337\041\044\052\051\073\254' .
+ '\055\057\302\304\300\301\303\305\307\321\246\054\045\137\076\077' .
+ '\370\311\312\313\310\315\316\317\314\140\072\043\100\047\075\042' .
+ '\330\141\142\143\144\145\146\147\150\151\253\273\360\375\376\261' .
+ '\260\152\153\154\155\156\157\160\161\162\252\272\346\270\306\244' .
+ '\265\176\163\164\165\166\167\170\171\172\241\277\320\335\336\256' .
+ '\136\243\245\267\251\247\266\274\275\276\133\135\257\250\264\327' .
+ '\173\101\102\103\104\105\106\107\110\111\255\364\366\362\363\365' .
+ '\175\112\113\114\115\116\117\120\121\122\271\373\374\371\372\377' .
+ '\134\367\123\124\125\126\127\130\131\132\262\324\326\322\323\325' .
+ '\060\061\062\063\064\065\066\067\070\071\263\333\334\331\332\237' ;
+
+ my $ebcdic_string = $ascii_string;
+ eval '$ebcdic_string =~ tr/' . $cp_037 . '/\000-\377/';
+
+To convert from EBCDIC 037 to ASCII just reverse the order of the tr///
+arguments like so:
+
+ my $ascii_string = $ebcdic_string;
+ eval '$ascii_string =~ tr/\000-\377/' . $cp_037 . '/';
+
+Similarly one could take the output of the third column from recipe 0 to
+obtain a C<$cp_1047> table. The fourth column of the output from recipe
+0 could provide a C<$cp_posix_bc> table suitable for transcoding as well.
+
+=head2 iconv
+
+XPG operability often implies the presence of an I<iconv> utility
+available from the shell or from the C library. Consult your system's
+documentation for information on iconv.
+
+On OS/390 or z/OS see the iconv(1) manpage. One way to invoke the iconv
+shell utility from within perl would be to:
+
+ # OS/390 or z/OS example
+ $ascii_data = `echo '$ebcdic_data'| iconv -f IBM-1047 -t ISO8859-1`
+
+or the inverse map:
+
+ # OS/390 or z/OS example
+ $ebcdic_data = `echo '$ascii_data'| iconv -f ISO8859-1 -t IBM-1047`
+
+For other perl based conversion options see the Convert::* modules on CPAN.
+
+=head2 C RTL
+
+The OS/390 and z/OS C run time libraries provide _atoe() and _etoa() functions.
+
+=head1 OPERATOR DIFFERENCES
+
+The C<..> range operator treats certain character ranges with
+care on EBCDIC platforms. For example the following array
+will have twenty six elements on either an EBCDIC platform
+or an ASCII platform:
+
+ @alphabet = ('A'..'Z'); # $#alphabet == 25
+
+The bitwise operators such as & ^ | may return different results
+when operating on string or character data in a perl program running
+on an EBCDIC platform than when run on an ASCII platform. Here is
+an example adapted from the one in L<perlop>:
+
+ # EBCDIC-based examples
+ print "j p \n" ^ " a h"; # prints "JAPH\n"
+ print "JA" | " ph\n"; # prints "japh\n"
+ print "JAPH\nJunk" & "\277\277\277\277\277"; # prints "japh\n";
+ print 'p N$' ^ " E<H\n"; # prints "Perl\n";
+
+An interesting property of the 32 C0 control characters
+in the ASCII table is that they can "literally" be constructed
+as control characters in perl, e.g. C<(chr(0) eq C<\c@>)>
+C<(chr(1) eq C<\cA>)>, and so on. Perl on EBCDIC platforms has been
+ported to take C<\c@> to chr(0) and C<\cA> to chr(1), etc. as well, but the
+thirty three characters that result depend on which code page you are
+using. The table below uses the standard acronyms for the controls.
+The POSIX-BC and 1047 sets are
+identical throughout this range and differ from the 0037 set at only
+one spot (21 decimal). Note that the C<LINE FEED> character
+may be generated by C<\cJ> on ASCII platforms but by C<\cU> on 1047 or POSIX-BC
+platforms and cannot be generated as a C<"\c.letter."> control character on
+0037 platforms. Note also that C<\c\> cannot be the final element in a string
+or regex, as it will absorb the terminator. But C<\c\I<X>> is a C<FILE
+SEPARATOR> concatenated with I<X> for all I<X>.
+
+ chr ord 8859-1 0037 1047 && POSIX-BC
+ ------------------------------------------------------------------------
+ \c? 127 <DEL> " "
+ \c@ 0 <NUL> <NUL> <NUL>
+ \cA 1 <SOH> <SOH> <SOH>
+ \cB 2 <STX> <STX> <STX>
+ \cC 3 <ETX> <ETX> <ETX>
+ \cD 4 <EOT> <ST> <ST>
+ \cE 5 <ENQ> <HT> <HT>
+ \cF 6 <ACK> <SSA> <SSA>
+ \cG 7 <BEL> <DEL> <DEL>
+ \cH 8 <BS> <EPA> <EPA>
+ \cI 9 <HT> <RI> <RI>
+ \cJ 10 <LF> <SS2> <SS2>
+ \cK 11 <VT> <VT> <VT>
+ \cL 12 <FF> <FF> <FF>
+ \cM 13 <CR> <CR> <CR>
+ \cN 14 <SO> <SO> <SO>
+ \cO 15 <SI> <SI> <SI>
+ \cP 16 <DLE> <DLE> <DLE>
+ \cQ 17 <DC1> <DC1> <DC1>
+ \cR 18 <DC2> <DC2> <DC2>
+ \cS 19 <DC3> <DC3> <DC3>
+ \cT 20 <DC4> <OSC> <OSC>
+ \cU 21 <NAK> <NEL> <LF> ***
+ \cV 22 <SYN> <BS> <BS>
+ \cW 23 <ETB> <ESA> <ESA>
+ \cX 24 <CAN> <CAN> <CAN>
+ \cY 25 <EOM> <EOM> <EOM>
+ \cZ 26 <SUB> <PU2> <PU2>
+ \c[ 27 <ESC> <SS3> <SS3>
+ \c\X 28 <FS>X <FS>X <FS>X
+ \c] 29 <GS> <GS> <GS>
+ \c^ 30 <RS> <RS> <RS>
+ \c_ 31 <US> <US> <US>
+
+=head1 FUNCTION DIFFERENCES
+
+=over 8
+
+=item chr()
+
+chr() must be given an EBCDIC code number argument to yield a desired
+character return value on an EBCDIC platform. For example:
+
+ $CAPITAL_LETTER_A = chr(193);
+
+=item ord()
+
+ord() will return EBCDIC code number values on an EBCDIC platform.
+For example:
+
+ $the_number_193 = ord("A");
+
+=item pack()
+
+The c and C templates for pack() are dependent upon character set
+encoding. Examples of usage on EBCDIC include:
+
+ $foo = pack("CCCC",193,194,195,196);
+ # $foo eq "ABCD"
+ $foo = pack("C4",193,194,195,196);
+ # same thing
+
+ $foo = pack("ccxxcc",193,194,195,196);
+ # $foo eq "AB\0\0CD"
+
+=item print()
+
+One must be careful with scalars and strings that are passed to
+print that contain ASCII encodings. One common place
+for this to occur is in the output of the MIME type header for
+CGI script writing. For example, many perl programming guides
+recommend something similar to:
+
+ print "Content-type:\ttext/html\015\012\015\012";
+ # this may be wrong on EBCDIC
+
+Under the IBM OS/390 USS Web Server or WebSphere on z/OS for example
+you should instead write that as:
+
+ print "Content-type:\ttext/html\r\n\r\n"; # OK for DGW et alia
+
+That is because the translation from EBCDIC to ASCII is done
+by the web server in this case (such code will not be appropriate for
+the Macintosh however). Consult your web server's documentation for
+further details.
+
+=item printf()
+
+The formats that can convert characters to numbers and vice versa
+will be different from their ASCII counterparts when executed
+on an EBCDIC platform. Examples include:
+
+ printf("%c%c%c",193,194,195); # prints ABC
+
+=item sort()
+
+EBCDIC sort results may differ from ASCII sort results especially for
+mixed case strings. This is discussed in more detail below.
+
+=item sprintf()
+
+See the discussion of printf() above. An example of the use
+of sprintf would be:
+
+ $CAPITAL_LETTER_A = sprintf("%c",193);
+
+=item unpack()
+
+See the discussion of pack() above.
+
+=back
+
+=head1 REGULAR EXPRESSION DIFFERENCES
+
+As of perl 5.005_03 the letter range regular expression such as
+[A-Z] and [a-z] have been especially coded to not pick up gap
+characters. For example, characters such as E<ocirc> C<o WITH CIRCUMFLEX>
+that lie between I and J would not be matched by the
+regular expression range C</[H-K]/>. This works in
+the other direction, too, if either of the range end points is
+explicitly numeric: C<[\x89-\x91]> will match C<\x8e>, even
+though C<\x89> is C<i> and C<\x91 > is C<j>, and C<\x8e>
+is a gap character from the alphabetic viewpoint.
+
+If you do want to match the alphabet gap characters in a single octet
+regular expression try matching the hex or octal code such
+as C</\313/> on EBCDIC or C</\364/> on ASCII platforms to
+have your regular expression match C<o WITH CIRCUMFLEX>.
+
+Another construct to be wary of is the inappropriate use of hex or
+octal constants in regular expressions. Consider the following
+set of subs:
+
+ sub is_c0 {
+ my $char = substr(shift,0,1);
+ $char =~ /[\000-\037]/;
+ }
+
+ sub is_print_ascii {
+ my $char = substr(shift,0,1);
+ $char =~ /[\040-\176]/;
+ }
+
+ sub is_delete {
+ my $char = substr(shift,0,1);
+ $char eq "\177";
+ }
+
+ sub is_c1 {
+ my $char = substr(shift,0,1);
+ $char =~ /[\200-\237]/;
+ }
+
+ sub is_latin_1 {
+ my $char = substr(shift,0,1);
+ $char =~ /[\240-\377]/;
+ }
+
+The above would be adequate if the concern was only with numeric code points.
+However, the concern may be with characters rather than code points
+and on an EBCDIC platform it may be desirable for constructs such as
+C<if (is_print_ascii("A")) {print "A is a printable character\n";}> to print
+out the expected message. One way to represent the above collection
+of character classification subs that is capable of working across the
+four coded character sets discussed in this document is as follows:
+
+ sub Is_c0 {
+ my $char = substr(shift,0,1);
+ if (ord('^')==94) { # ascii
+ return $char =~ /[\000-\037]/;
+ }
+ if (ord('^')==176) { # 0037
+ return $char =~ /[\000-\003\067\055-\057\026\005\045\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
+ }
+ if (ord('^')==95 || ord('^')==106) { # 1047 || posix-bc
+ return $char =~ /[\000-\003\067\055-\057\026\005\025\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
+ }
+ }
+
+ sub Is_print_ascii {
+ my $char = substr(shift,0,1);
+ $char =~ /[ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/;
+ }
+
+ sub Is_delete {
+ my $char = substr(shift,0,1);
+ if (ord('^')==94) { # ascii
+ return $char eq "\177";
+ }
+ else { # ebcdic
+ return $char eq "\007";
+ }
+ }
+
+ sub Is_c1 {
+ my $char = substr(shift,0,1);
+ if (ord('^')==94) { # ascii
+ return $char =~ /[\200-\237]/;
+ }
+ if (ord('^')==176) { # 0037
+ return $char =~ /[\040-\044\025\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
+ }
+ if (ord('^')==95) { # 1047
+ return $char =~ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
+ }
+ if (ord('^')==106) { # posix-bc
+ return $char =~
+ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\137]/;
+ }
+ }
+
+ sub Is_latin_1 {
+ my $char = substr(shift,0,1);
+ if (ord('^')==94) { # ascii
+ return $char =~ /[\240-\377]/;
+ }
+ if (ord('^')==176) { # 0037
+ return $char =~
+ /[\101\252\112\261\237\262\152\265\275\264\232\212\137\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/;
+ }
+ if (ord('^')==95) { # 1047
+ return $char =~
+ /[\101\252\112\261\237\262\152\265\273\264\232\212\260\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\272\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/;
+ }
+ if (ord('^')==106) { # posix-bc
+ return $char =~
+ /[\101\252\260\261\237\262\320\265\171\264\232\212\272\312\257\241\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\340\376\335\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\300\336\333\334\215\216\337]/;
+ }
+ }
+
+Note however that only the C<Is_ascii_print()> sub is really independent
+of coded character set. Another way to write C<Is_latin_1()> would be
+to use the characters in the range explicitly:
+
+ sub Is_latin_1 {
+ my $char = substr(shift,0,1);
+ $char =~ /[ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÃÂÃÄÅÆÇÈÉÊËÌÃÃŽÃÃÑÒÓÔÕÖ×ØÙÚÛÜÃÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ]/;
+ }
+
+Although that form may run into trouble in network transit (due to the
+presence of 8 bit characters) or on non ISO-Latin character sets.
+
+=head1 SOCKETS
+
+Most socket programming assumes ASCII character encodings in network
+byte order. Exceptions can include CGI script writing under a
+host web server where the server may take care of translation for you.
+Most host web servers convert EBCDIC data to ISO-8859-1 or Unicode on
+output.
+
+=head1 SORTING
+
+One big difference between ASCII based character sets and EBCDIC ones
+are the relative positions of upper and lower case letters and the
+letters compared to the digits. If sorted on an ASCII based platform the
+two letter abbreviation for a physician comes before the two letter
+for drive, that is:
+
+ @sorted = sort(qw(Dr. dr.)); # @sorted holds ('Dr.','dr.') on ASCII,
+ # but ('dr.','Dr.') on EBCDIC
+
+The property of lower case before uppercase letters in EBCDIC is
+even carried to the Latin 1 EBCDIC pages such as 0037 and 1047.
+An example would be that E<Euml> C<E WITH DIAERESIS> (203) comes
+before E<euml> C<e WITH DIAERESIS> (235) on an ASCII platform, but
+the latter (83) comes before the former (115) on an EBCDIC platform.
+(Astute readers will note that the upper case version of E<szlig>
+C<SMALL LETTER SHARP S> is simply "SS" and that the upper case version of
+E<yuml> C<y WITH DIAERESIS> is not in the 0..255 range but it is
+at U+x0178 in Unicode, or C<"\x{178}"> in a Unicode enabled Perl).
+
+The sort order will cause differences between results obtained on
+ASCII platforms versus EBCDIC platforms. What follows are some suggestions
+on how to deal with these differences.
+
+=head2 Ignore ASCII vs. EBCDIC sort differences.
+
+This is the least computationally expensive strategy. It may require
+some user education.
+
+=head2 MONO CASE then sort data.
+
+In order to minimize the expense of mono casing mixed test try to
+C<tr///> towards the character set case most employed within the data.
+If the data are primarily UPPERCASE non Latin 1 then apply tr/[a-z]/[A-Z]/
+then sort(). If the data are primarily lowercase non Latin 1 then
+apply tr/[A-Z]/[a-z]/ before sorting. If the data are primarily UPPERCASE
+and include Latin-1 characters then apply:
+
+ tr/[a-z]/[A-Z]/;
+ tr/[àáâãäåæçèéêëìíîïðñòóôõöøùúûüýþ]/[ÀÃÂÃÄÅÆÇÈÉÊËÌÃÃŽÃÃÑÒÓÔÕÖØÙÚÛÜÃÞ/;
+ s/ß/SS/g;
+
+then sort(). Do note however that such Latin-1 manipulation does not
+address the E<yuml> C<y WITH DIAERESIS> character that will remain at
+code point 255 on ASCII platforms, but 223 on most EBCDIC platforms
+where it will sort to a place less than the EBCDIC numerals. With a
+Unicode enabled Perl you might try:
+
+ tr/^?/\x{178}/;
+
+The strategy of mono casing data before sorting does not preserve the case
+of the data and may not be acceptable for that reason.
+
+=head2 Convert, sort data, then re convert.
+
+This is the most expensive proposition that does not employ a network
+connection.
+
+=head2 Perform sorting on one type of platform only.
+
+This strategy can employ a network connection. As such
+it would be computationally expensive.
+
+=head1 TRANSFORMATION FORMATS
+
+There are a variety of ways of transforming data with an intra character set
+mapping that serve a variety of purposes. Sorting was discussed in the
+previous section and a few of the other more popular mapping techniques are
+discussed next.
+
+=head2 URL decoding and encoding
+
+Note that some URLs have hexadecimal ASCII code points in them in an
+attempt to overcome character or protocol limitation issues. For example
+the tilde character is not on every keyboard hence a URL of the form:
+
+ http://www.pvhp.com/~pvhp/
+
+may also be expressed as either of:
+
+ http://www.pvhp.com/%7Epvhp/
+
+ http://www.pvhp.com/%7epvhp/
+
+where 7E is the hexadecimal ASCII code point for '~'. Here is an example
+of decoding such a URL under CCSID 1047:
+
+ $url = 'http://www.pvhp.com/%7Epvhp/';
+ # this array assumes code page 1047
+ my @a2e_1047 = (
+ 0, 1, 2, 3, 55, 45, 46, 47, 22, 5, 21, 11, 12, 13, 14, 15,
+ 16, 17, 18, 19, 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31,
+ 64, 90,127,123, 91,108, 80,125, 77, 93, 92, 78,107, 96, 75, 97,
+ 240,241,242,243,244,245,246,247,248,249,122, 94, 76,126,110,111,
+ 124,193,194,195,196,197,198,199,200,201,209,210,211,212,213,214,
+ 215,216,217,226,227,228,229,230,231,232,233,173,224,189, 95,109,
+ 121,129,130,131,132,133,134,135,136,137,145,146,147,148,149,150,
+ 151,152,153,162,163,164,165,166,167,168,169,192, 79,208,161, 7,
+ 32, 33, 34, 35, 36, 37, 6, 23, 40, 41, 42, 43, 44, 9, 10, 27,
+ 48, 49, 26, 51, 52, 53, 54, 8, 56, 57, 58, 59, 4, 20, 62,255,
+ 65,170, 74,177,159,178,106,181,187,180,154,138,176,202,175,188,
+ 144,143,234,250,190,160,182,179,157,218,155,139,183,184,185,171,
+ 100,101, 98,102, 99,103,158,104,116,113,114,115,120,117,118,119,
+ 172,105,237,238,235,239,236,191,128,253,254,251,252,186,174, 89,
+ 68, 69, 66, 70, 67, 71,156, 72, 84, 81, 82, 83, 88, 85, 86, 87,
+ 140, 73,205,206,203,207,204,225,112,221,222,219,220,141,142,223
+ );
+ $url =~ s/%([0-9a-fA-F]{2})/pack("c",$a2e_1047[hex($1)])/ge;
+
+Conversely, here is a partial solution for the task of encoding such
+a URL under the 1047 code page:
+
+ $url = 'http://www.pvhp.com/~pvhp/';
+ # this array assumes code page 1047
+ my @e2a_1047 = (
+ 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15,
+ 16, 17, 18, 19,157, 10, 8,135, 24, 25,146,143, 28, 29, 30, 31,
+ 128,129,130,131,132,133, 23, 27,136,137,138,139,140, 5, 6, 7,
+ 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26,
+ 32,160,226,228,224,225,227,229,231,241,162, 46, 60, 40, 43,124,
+ 38,233,234,235,232,237,238,239,236,223, 33, 36, 42, 41, 59, 94,
+ 45, 47,194,196,192,193,195,197,199,209,166, 44, 37, 95, 62, 63,
+ 248,201,202,203,200,205,206,207,204, 96, 58, 35, 64, 39, 61, 34,
+ 216, 97, 98, 99,100,101,102,103,104,105,171,187,240,253,254,177,
+ 176,106,107,108,109,110,111,112,113,114,170,186,230,184,198,164,
+ 181,126,115,116,117,118,119,120,121,122,161,191,208, 91,222,174,
+ 172,163,165,183,169,167,182,188,189,190,221,168,175, 93,180,215,
+ 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,173,244,246,242,243,245,
+ 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,185,251,252,249,250,255,
+ 92,247, 83, 84, 85, 86, 87, 88, 89, 90,178,212,214,210,211,213,
+ 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,179,219,220,217,218,159
+ );
+ # The following regular expression does not address the
+ # mappings for: ('.' => '%2E', '/' => '%2F', ':' => '%3A')
+ $url =~ s/([\t "#%&\(\),;<=>\?\@\[\\\]^`{|}~])/sprintf("%%%02X",$e2a_1047[ord($1)])/ge;
+
+where a more complete solution would split the URL into components
+and apply a full s/// substitution only to the appropriate parts.
+
+In the remaining examples a @e2a or @a2e array may be employed
+but the assignment will not be shown explicitly. For code page 1047
+you could use the @a2e_1047 or @e2a_1047 arrays just shown.
+
+=head2 uu encoding and decoding
+
+The C<u> template to pack() or unpack() will render EBCDIC data in EBCDIC
+characters equivalent to their ASCII counterparts. For example, the
+following will print "Yes indeed\n" on either an ASCII or EBCDIC computer:
+
+ $all_byte_chrs = '';
+ for (0..255) { $all_byte_chrs .= chr($_); }
+ $uuencode_byte_chrs = pack('u', $all_byte_chrs);
+ ($uu = <<'ENDOFHEREDOC') =~ s/^\s*//gm;
+ M``$"`P0%!@<("0H+#`T.#Q`1$A,4%187&!D:&QP='A\@(2(C)"4F)R@I*BLL
+ M+2XO,#$R,S0U-C<X.3H[/#T^/T!!0D-$149'2$E*2TQ-3D]045)35%565UA9
+ M6EM<75Y?8&%B8V1E9F=H:6IK;&UN;W!Q<G-T=79W>'EZ>WQ]?G^`@8*#A(6&
+ MAXB)BHN,C8Z/D)&2DY25EI>8F9J;G)V>GZ"AHJ.DI::GJ*FJJZRMKJ^PL;*S
+ MM+6VM[BYNKN\O;Z_P,'"P\3%QL?(R<K+S,W.S]#1TM/4U=;7V-G:V]S=WM_@
+ ?X>+CY.7FY^CIZNOL[>[O\/'R\_3U]O?X^?K[_/W^_P``
+ ENDOFHEREDOC
+ if ($uuencode_byte_chrs eq $uu) {
+ print "Yes ";
+ }
+ $uudecode_byte_chrs = unpack('u', $uuencode_byte_chrs);
+ if ($uudecode_byte_chrs eq $all_byte_chrs) {
+ print "indeed\n";
+ }
+
+Here is a very spartan uudecoder that will work on EBCDIC provided
+that the @e2a array is filled in appropriately:
+
+ #!/usr/local/bin/perl
+ @e2a = ( # this must be filled in
+ );
+ $_ = <> until ($mode,$file) = /^begin\s*(\d*)\s*(\S*)/;
+ open(OUT, "> $file") if $file ne "";
+ while(<>) {
+ last if /^end/;
+ next if /[a-z]/;
+ next unless int(((($e2a[ord()] - 32 ) & 077) + 2) / 3) ==
+ int(length() / 4);
+ print OUT unpack("u", $_);
+ }
+ close(OUT);
+ chmod oct($mode), $file;
+
+
+=head2 Quoted-Printable encoding and decoding
+
+On ASCII encoded platforms it is possible to strip characters outside of
+the printable set using:
+
+ # This QP encoder works on ASCII only
+ $qp_string =~ s/([=\x00-\x1F\x80-\xFF])/sprintf("=%02X",ord($1))/ge;
+
+Whereas a QP encoder that works on both ASCII and EBCDIC platforms
+would look somewhat like the following (where the EBCDIC branch @e2a
+array is omitted for brevity):
+
+ if (ord('A') == 65) { # ASCII
+ $delete = "\x7F"; # ASCII
+ @e2a = (0 .. 255) # ASCII to ASCII identity map
+ }
+ else { # EBCDIC
+ $delete = "\x07"; # EBCDIC
+ @e2a = # EBCDIC to ASCII map (as shown above)
+ }
+ $qp_string =~
+ s/([^ !"\#\$%&'()*+,\-.\/0-9:;<>?\@A-Z[\\\]^_`a-z{|}~$delete])/sprintf("=%02X",$e2a[ord($1)])/ge;
+
+(although in production code the substitutions might be done
+in the EBCDIC branch with the @e2a array and separately in the
+ASCII branch without the expense of the identity map).
+
+Such QP strings can be decoded with:
+
+ # This QP decoder is limited to ASCII only
+ $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr hex $1/ge;
+ $string =~ s/=[\n\r]+$//;
+
+Whereas a QP decoder that works on both ASCII and EBCDIC platforms
+would look somewhat like the following (where the @a2e array is
+omitted for brevity):
+
+ $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr $a2e[hex $1]/ge;
+ $string =~ s/=[\n\r]+$//;
+
+=head2 Caesarian ciphers
+
+The practice of shifting an alphabet one or more characters for encipherment
+dates back thousands of years and was explicitly detailed by Gaius Julius
+Caesar in his B<Gallic Wars> text. A single alphabet shift is sometimes
+referred to as a rotation and the shift amount is given as a number $n after
+the string 'rot' or "rot$n". Rot0 and rot26 would designate identity maps
+on the 26 letter English version of the Latin alphabet. Rot13 has the
+interesting property that alternate subsequent invocations are identity maps
+(thus rot13 is its own non-trivial inverse in the group of 26 alphabet
+rotations). Hence the following is a rot13 encoder and decoder that will
+work on ASCII and EBCDIC platforms:
+
+ #!/usr/local/bin/perl
+
+ while(<>){
+ tr/n-za-mN-ZA-M/a-zA-Z/;
+ print;
+ }
+
+In one-liner form:
+
+ perl -ne 'tr/n-za-mN-ZA-M/a-zA-Z/;print'
+
+
+=head1 Hashing order and checksums
+
+To the extent that it is possible to write code that depends on
+hashing order there may be differences between hashes as stored
+on an ASCII based platform and hashes stored on an EBCDIC based platform.
+XXX
+
+=head1 I18N AND L10N
+
+Internationalization(I18N) and localization(L10N) are supported at least
+in principle even on EBCDIC platforms. The details are system dependent
+and discussed under the L<perlebcdic/OS ISSUES> section below.
+
+=head1 MULTI OCTET CHARACTER SETS
+
+Perl may work with an internal UTF-EBCDIC encoding form for wide characters
+on EBCDIC platforms in a manner analogous to the way that it works with
+the UTF-8 internal encoding form on ASCII based platforms.
+
+Legacy multi byte EBCDIC code pages XXX.
+
+=head1 OS ISSUES
+
+There may be a few system dependent issues
+of concern to EBCDIC Perl programmers.
+
+=head2 OS/400
+
+=over 8
+
+=item PASE
+
+The PASE environment is runtime environment for OS/400 that can run
+executables built for PowerPC AIX in OS/400, see L<perlos400>. PASE
+is ASCII-based, not EBCDIC-based as the ILE.
+
+=item IFS access
+
+XXX.
+
+=back
+
+=head2 OS/390, z/OS
+
+Perl runs under Unix Systems Services or USS.
+
+=over 8
+
+=item chcp
+
+B<chcp> is supported as a shell utility for displaying and changing
+one's code page. See also L<chcp>.
+
+=item dataset access
+
+For sequential data set access try:
+
+ my @ds_records = `cat //DSNAME`;
+
+or:
+
+ my @ds_records = `cat //'HLQ.DSNAME'`;
+
+See also the OS390::Stdio module on CPAN.
+
+=item OS/390, z/OS iconv
+
+B<iconv> is supported as both a shell utility and a C RTL routine.
+See also the iconv(1) and iconv(3) manual pages.
+
+=item locales
+
+On OS/390 or z/OS see L<locale> for information on locales. The L10N files
+are in F</usr/nls/locale>. $Config{d_setlocale} is 'define' on OS/390
+or z/OS.
+
+=back
+
+=head2 VM/ESA?
+
+XXX.
+
+=head2 POSIX-BC?
+
+XXX.
+
+=head1 BUGS
+
+This pod document contains literal Latin 1 characters and may encounter
+translation difficulties. In particular one popular nroff implementation
+was known to strip accented characters to their unaccented counterparts
+while attempting to view this document through the B<pod2man> program
+(for example, you may see a plain C<y> rather than one with a diaeresis
+as in E<yuml>). Another nroff truncated the resultant manpage at
+the first occurrence of 8 bit characters.
+
+Not all shells will allow multiple C<-e> string arguments to perl to
+be concatenated together properly as recipes 0, 2, 4, 5, and 6 might
+seem to imply.
+
+=head1 SEE ALSO
+
+L<perllocale>, L<perlfunc>, L<perlunicode>, L<utf8>.
+
+=head1 REFERENCES
+
+L<http://anubis.dkuug.dk/i18n/charmaps>
+
+L<http://www.unicode.org/>
+
+L<http://www.unicode.org/unicode/reports/tr16/>
+
+L<http://www.wps.com/projects/codes/>
+B<ASCII: American Standard Code for Information Infiltration> Tom Jennings,
+September 1999.
+
+B<The Unicode Standard, Version 3.0> The Unicode Consortium, Lisa Moore ed.,
+ISBN 0-201-61633-5, Addison Wesley Developers Press, February 2000.
+
+B<CDRA: IBM - Character Data Representation Architecture -
+Reference and Registry>, IBM SC09-2190-00, December 1996.
+
+"Demystifying Character Sets", Andrea Vine, Multilingual Computing
+& Technology, B<#26 Vol. 10 Issue 4>, August/September 1999;
+ISSN 1523-0309; Multilingual Computing Inc. Sandpoint ID, USA.
+
+B<Codes, Ciphers, and Other Cryptic and Clandestine Communication>
+Fred B. Wrixon, ISBN 1-57912-040-7, Black Dog & Leventhal Publishers,
+1998.
+
+L<http://www.bobbemer.com/P-BIT.HTM>
+B<IBM - EBCDIC and the P-bit; The biggest Computer Goof Ever> Robert Bemer.
+
+=head1 HISTORY
+
+15 April 2001: added UTF-8 and UTF-EBCDIC to main table, pvhp.
+
+=head1 AUTHOR
+
+Peter Prymmer pvhp@best.com wrote this in 1999 and 2000
+with CCSID 0819 and 0037 help from Chris Leach and
+AndrE<eacute> Pirard A.Pirard@ulg.ac.be as well as POSIX-BC
+help from Thomas Dorner Thomas.Dorner@start.de.
+Thanks also to Vickie Cooper, Philip Newton, William Raffloer, and
+Joe Smith. Trademarks, registered trademarks, service marks and
+registered service marks used in this document are the property of
+their respective owners.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlembed.pod b/Master/tlpkg/tlperl/lib/pods/perlembed.pod
new file mode 100644
index 00000000000..5ecaed04d06
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlembed.pod
@@ -0,0 +1,1160 @@
+=head1 NAME
+
+perlembed - how to embed perl in your C program
+
+=head1 DESCRIPTION
+
+=head2 PREAMBLE
+
+Do you want to:
+
+=over 5
+
+=item B<Use C from Perl?>
+
+Read L<perlxstut>, L<perlxs>, L<h2xs>, L<perlguts>, and L<perlapi>.
+
+=item B<Use a Unix program from Perl?>
+
+Read about back-quotes and about C<system> and C<exec> in L<perlfunc>.
+
+=item B<Use Perl from Perl?>
+
+Read about L<perlfunc/do> and L<perlfunc/eval> and L<perlfunc/require>
+and L<perlfunc/use>.
+
+=item B<Use C from C?>
+
+Rethink your design.
+
+=item B<Use Perl from C?>
+
+Read on...
+
+=back
+
+=head2 ROADMAP
+
+=over 5
+
+=item *
+
+Compiling your C program
+
+=item *
+
+Adding a Perl interpreter to your C program
+
+=item *
+
+Calling a Perl subroutine from your C program
+
+=item *
+
+Evaluating a Perl statement from your C program
+
+=item *
+
+Performing Perl pattern matches and substitutions from your C program
+
+=item *
+
+Fiddling with the Perl stack from your C program
+
+=item *
+
+Maintaining a persistent interpreter
+
+=item *
+
+Maintaining multiple interpreter instances
+
+=item *
+
+Using Perl modules, which themselves use C libraries, from your C program
+
+=item *
+
+Embedding Perl under Win32
+
+=back
+
+=head2 Compiling your C program
+
+If you have trouble compiling the scripts in this documentation,
+you're not alone. The cardinal rule: COMPILE THE PROGRAMS IN EXACTLY
+THE SAME WAY THAT YOUR PERL WAS COMPILED. (Sorry for yelling.)
+
+Also, every C program that uses Perl must link in the I<perl library>.
+What's that, you ask? Perl is itself written in C; the perl library
+is the collection of compiled C programs that were used to create your
+perl executable (I</usr/bin/perl> or equivalent). (Corollary: you
+can't use Perl from your C program unless Perl has been compiled on
+your machine, or installed properly--that's why you shouldn't blithely
+copy Perl executables from machine to machine without also copying the
+I<lib> directory.)
+
+When you use Perl from C, your C program will--usually--allocate,
+"run", and deallocate a I<PerlInterpreter> object, which is defined by
+the perl library.
+
+If your copy of Perl is recent enough to contain this documentation
+(version 5.002 or later), then the perl library (and I<EXTERN.h> and
+I<perl.h>, which you'll also need) will reside in a directory
+that looks like this:
+
+ /usr/local/lib/perl5/your_architecture_here/CORE
+
+or perhaps just
+
+ /usr/local/lib/perl5/CORE
+
+or maybe something like
+
+ /usr/opt/perl5/CORE
+
+Execute this statement for a hint about where to find CORE:
+
+ perl -MConfig -e 'print $Config{archlib}'
+
+Here's how you'd compile the example in the next section,
+L<Adding a Perl interpreter to your C program>, on my Linux box:
+
+ % gcc -O2 -Dbool=char -DHAS_BOOL -I/usr/local/include
+ -I/usr/local/lib/perl5/i586-linux/5.003/CORE
+ -L/usr/local/lib/perl5/i586-linux/5.003/CORE
+ -o interp interp.c -lperl -lm
+
+(That's all one line.) On my DEC Alpha running old 5.003_05, the
+incantation is a bit different:
+
+ % cc -O2 -Olimit 2900 -DSTANDARD_C -I/usr/local/include
+ -I/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE
+ -L/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE -L/usr/local/lib
+ -D__LANGUAGE_C__ -D_NO_PROTO -o interp interp.c -lperl -lm
+
+How can you figure out what to add? Assuming your Perl is post-5.001,
+execute a C<perl -V> command and pay special attention to the "cc" and
+"ccflags" information.
+
+You'll have to choose the appropriate compiler (I<cc>, I<gcc>, et al.) for
+your machine: C<perl -MConfig -e 'print $Config{cc}'> will tell you what
+to use.
+
+You'll also have to choose the appropriate library directory
+(I</usr/local/lib/...>) for your machine. If your compiler complains
+that certain functions are undefined, or that it can't locate
+I<-lperl>, then you need to change the path following the C<-L>. If it
+complains that it can't find I<EXTERN.h> and I<perl.h>, you need to
+change the path following the C<-I>.
+
+You may have to add extra libraries as well. Which ones?
+Perhaps those printed by
+
+ perl -MConfig -e 'print $Config{libs}'
+
+Provided your perl binary was properly configured and installed the
+B<ExtUtils::Embed> module will determine all of this information for
+you:
+
+ % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+If the B<ExtUtils::Embed> module isn't part of your Perl distribution,
+you can retrieve it from
+http://www.perl.com/perl/CPAN/modules/by-module/ExtUtils/
+(If this documentation came from your Perl distribution, then you're
+running 5.004 or better and you already have it.)
+
+The B<ExtUtils::Embed> kit on CPAN also contains all source code for
+the examples in this document, tests, additional examples and other
+information you may find useful.
+
+=head2 Adding a Perl interpreter to your C program
+
+In a sense, perl (the C program) is a good example of embedding Perl
+(the language), so I'll demonstrate embedding with I<miniperlmain.c>,
+included in the source distribution. Here's a bastardized, non-portable
+version of I<miniperlmain.c> containing the essentials of embedding:
+
+ #include <EXTERN.h> /* from the Perl distribution */
+ #include <perl.h> /* from the Perl distribution */
+
+ static PerlInterpreter *my_perl; /*** The Perl interpreter ***/
+
+ int main(int argc, char **argv, char **env)
+ {
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct(my_perl);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ perl_parse(my_perl, NULL, argc, argv, (char **)NULL);
+ perl_run(my_perl);
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
+
+Notice that we don't use the C<env> pointer. Normally handed to
+C<perl_parse> as its final argument, C<env> here is replaced by
+C<NULL>, which means that the current environment will be used.
+
+The macros PERL_SYS_INIT3() and PERL_SYS_TERM() provide system-specific
+tune up of the C runtime environment necessary to run Perl interpreters;
+they should only be called once regardless of how many interpreters you
+create or destroy. Call PERL_SYS_INIT3() before you create your first
+interpreter, and PERL_SYS_TERM() after you free your last interpreter.
+
+Since PERL_SYS_INIT3() may change C<env>, it may be more appropriate to
+provide C<env> as an argument to perl_parse().
+
+Also notice that no matter what arguments you pass to perl_parse(),
+PERL_SYS_INIT3() must be invoked on the C main() argc, argv and env and
+only once.
+
+Now compile this program (I'll call it I<interp.c>) into an executable:
+
+ % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+After a successful compilation, you'll be able to use I<interp> just
+like perl itself:
+
+ % interp
+ print "Pretty Good Perl \n";
+ print "10890 - 9801 is ", 10890 - 9801;
+ <CTRL-D>
+ Pretty Good Perl
+ 10890 - 9801 is 1089
+
+or
+
+ % interp -e 'printf("%x", 3735928559)'
+ deadbeef
+
+You can also read and execute Perl statements from a file while in the
+midst of your C program, by placing the filename in I<argv[1]> before
+calling I<perl_run>.
+
+=head2 Calling a Perl subroutine from your C program
+
+To call individual Perl subroutines, you can use any of the B<call_*>
+functions documented in L<perlcall>.
+In this example we'll use C<call_argv>.
+
+That's shown below, in a program I'll call I<showtime.c>.
+
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ static PerlInterpreter *my_perl;
+
+ int main(int argc, char **argv, char **env)
+ {
+ char *args[] = { NULL };
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct(my_perl);
+
+ perl_parse(my_perl, NULL, argc, argv, NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+
+ /*** skipping perl_run() ***/
+
+ call_argv("showtime", G_DISCARD | G_NOARGS, args);
+
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
+
+where I<showtime> is a Perl subroutine that takes no arguments (that's the
+I<G_NOARGS>) and for which I'll ignore the return value (that's the
+I<G_DISCARD>). Those flags, and others, are discussed in L<perlcall>.
+
+I'll define the I<showtime> subroutine in a file called I<showtime.pl>:
+
+ print "I shan't be printed.";
+
+ sub showtime {
+ print time;
+ }
+
+Simple enough. Now compile and run:
+
+ % cc -o showtime showtime.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+ % showtime showtime.pl
+ 818284590
+
+yielding the number of seconds that elapsed between January 1, 1970
+(the beginning of the Unix epoch), and the moment I began writing this
+sentence.
+
+In this particular case we don't have to call I<perl_run>, as we set
+the PL_exit_flag PERL_EXIT_DESTRUCT_END which executes END blocks in
+perl_destruct.
+
+If you want to pass arguments to the Perl subroutine, you can add
+strings to the C<NULL>-terminated C<args> list passed to
+I<call_argv>. For other data types, or to examine return values,
+you'll need to manipulate the Perl stack. That's demonstrated in
+L<Fiddling with the Perl stack from your C program>.
+
+=head2 Evaluating a Perl statement from your C program
+
+Perl provides two API functions to evaluate pieces of Perl code.
+These are L<perlapi/eval_sv> and L<perlapi/eval_pv>.
+
+Arguably, these are the only routines you'll ever need to execute
+snippets of Perl code from within your C program. Your code can be as
+long as you wish; it can contain multiple statements; it can employ
+L<perlfunc/use>, L<perlfunc/require>, and L<perlfunc/do> to
+include external Perl files.
+
+I<eval_pv> lets us evaluate individual Perl strings, and then
+extract variables for coercion into C types. The following program,
+I<string.c>, executes three Perl strings, extracting an C<int> from
+the first, a C<float> from the second, and a C<char *> from the third.
+
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ static PerlInterpreter *my_perl;
+
+ main (int argc, char **argv, char **env)
+ {
+ char *embedding[] = { "", "-e", "0" };
+
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct( my_perl );
+
+ perl_parse(my_perl, NULL, 3, embedding, NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ perl_run(my_perl);
+
+ /** Treat $a as an integer **/
+ eval_pv("$a = 3; $a **= 2", TRUE);
+ printf("a = %d\n", SvIV(get_sv("a", 0)));
+
+ /** Treat $a as a float **/
+ eval_pv("$a = 3.14; $a **= 2", TRUE);
+ printf("a = %f\n", SvNV(get_sv("a", 0)));
+
+ /** Treat $a as a string **/
+ eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
+ printf("a = %s\n", SvPV_nolen(get_sv("a", 0)));
+
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
+
+All of those strange functions with I<sv> in their names help convert Perl scalars to C types. They're described in L<perlguts> and L<perlapi>.
+
+If you compile and run I<string.c>, you'll see the results of using
+I<SvIV()> to create an C<int>, I<SvNV()> to create a C<float>, and
+I<SvPV()> to create a string:
+
+ a = 9
+ a = 9.859600
+ a = Just Another Perl Hacker
+
+In the example above, we've created a global variable to temporarily
+store the computed value of our eval'ed expression. It is also
+possible and in most cases a better strategy to fetch the return value
+from I<eval_pv()> instead. Example:
+
+ ...
+ SV *val = eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE);
+ printf("%s\n", SvPV_nolen(val));
+ ...
+
+This way, we avoid namespace pollution by not creating global
+variables and we've simplified our code as well.
+
+=head2 Performing Perl pattern matches and substitutions from your C program
+
+The I<eval_sv()> function lets us evaluate strings of Perl code, so we can
+define some functions that use it to "specialize" in matches and
+substitutions: I<match()>, I<substitute()>, and I<matches()>.
+
+ I32 match(SV *string, char *pattern);
+
+Given a string and a pattern (e.g., C<m/clasp/> or C</\b\w*\b/>, which
+in your C program might appear as "/\\b\\w*\\b/"), match()
+returns 1 if the string matches the pattern and 0 otherwise.
+
+ int substitute(SV **string, char *pattern);
+
+Given a pointer to an C<SV> and an C<=~> operation (e.g.,
+C<s/bob/robert/g> or C<tr[A-Z][a-z]>), substitute() modifies the string
+within the C<SV> as according to the operation, returning the number of substitutions
+made.
+
+ int matches(SV *string, char *pattern, AV **matches);
+
+Given an C<SV>, a pattern, and a pointer to an empty C<AV>,
+matches() evaluates C<$string =~ $pattern> in a list context, and
+fills in I<matches> with the array elements, returning the number of matches found.
+
+Here's a sample program, I<match.c>, that uses all three (long lines have
+been wrapped here):
+
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ static PerlInterpreter *my_perl;
+
+ /** my_eval_sv(code, error_check)
+ ** kinda like eval_sv(),
+ ** but we pop the return value off the stack
+ **/
+ SV* my_eval_sv(SV *sv, I32 croak_on_error)
+ {
+ dSP;
+ SV* retval;
+
+
+ PUSHMARK(SP);
+ eval_sv(sv, G_SCALAR);
+
+ SPAGAIN;
+ retval = POPs;
+ PUTBACK;
+
+ if (croak_on_error && SvTRUE(ERRSV))
+ croak(SvPVx_nolen(ERRSV));
+
+ return retval;
+ }
+
+ /** match(string, pattern)
+ **
+ ** Used for matches in a scalar context.
+ **
+ ** Returns 1 if the match was successful; 0 otherwise.
+ **/
+
+ I32 match(SV *string, char *pattern)
+ {
+ SV *command = newSV(0), *retval;
+
+ sv_setpvf(command, "my $string = '%s'; $string =~ %s",
+ SvPV_nolen(string), pattern);
+
+ retval = my_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ return SvIV(retval);
+ }
+
+ /** substitute(string, pattern)
+ **
+ ** Used for =~ operations that modify their left-hand side (s/// and tr///)
+ **
+ ** Returns the number of successful matches, and
+ ** modifies the input string if there were any.
+ **/
+
+ I32 substitute(SV **string, char *pattern)
+ {
+ SV *command = newSV(0), *retval;
+
+ sv_setpvf(command, "$string = '%s'; ($string =~ %s)",
+ SvPV_nolen(*string), pattern);
+
+ retval = my_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ *string = get_sv("string", 0);
+ return SvIV(retval);
+ }
+
+ /** matches(string, pattern, matches)
+ **
+ ** Used for matches in a list context.
+ **
+ ** Returns the number of matches,
+ ** and fills in **matches with the matching substrings
+ **/
+
+ I32 matches(SV *string, char *pattern, AV **match_list)
+ {
+ SV *command = newSV(0);
+ I32 num_matches;
+
+ sv_setpvf(command, "my $string = '%s'; @array = ($string =~ %s)",
+ SvPV_nolen(string), pattern);
+
+ my_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ *match_list = get_av("array", 0);
+ num_matches = av_len(*match_list) + 1; /** assume $[ is 0 **/
+
+ return num_matches;
+ }
+
+ main (int argc, char **argv, char **env)
+ {
+ char *embedding[] = { "", "-e", "0" };
+ AV *match_list;
+ I32 num_matches, i;
+ SV *text;
+
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct(my_perl);
+ perl_parse(my_perl, NULL, 3, embedding, NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+
+ text = newSV(0);
+ sv_setpv(text, "When he is at a convenience store and the "
+ "bill comes to some amount like 76 cents, Maynard is "
+ "aware that there is something he *should* do, something "
+ "that will enable him to get back a quarter, but he has "
+ "no idea *what*. He fumbles through his red squeezey "
+ "changepurse and gives the boy three extra pennies with "
+ "his dollar, hoping that he might luck into the correct "
+ "amount. The boy gives him back two of his own pennies "
+ "and then the big shiny quarter that is his prize. "
+ "-RICHH");
+
+ if (match(text, "m/quarter/")) /** Does text contain 'quarter'? **/
+ printf("match: Text contains the word 'quarter'.\n\n");
+ else
+ printf("match: Text doesn't contain the word 'quarter'.\n\n");
+
+ if (match(text, "m/eighth/")) /** Does text contain 'eighth'? **/
+ printf("match: Text contains the word 'eighth'.\n\n");
+ else
+ printf("match: Text doesn't contain the word 'eighth'.\n\n");
+
+ /** Match all occurrences of /wi../ **/
+ num_matches = matches(text, "m/(wi..)/g", &match_list);
+ printf("matches: m/(wi..)/g found %d matches...\n", num_matches);
+
+ for (i = 0; i < num_matches; i++)
+ printf("match: %s\n", SvPV_nolen(*av_fetch(match_list, i, FALSE)));
+ printf("\n");
+
+ /** Remove all vowels from text **/
+ num_matches = substitute(&text, "s/[aeiou]//gi");
+ if (num_matches) {
+ printf("substitute: s/[aeiou]//gi...%d substitutions made.\n",
+ num_matches);
+ printf("Now text is: %s\n\n", SvPV_nolen(text));
+ }
+
+ /** Attempt a substitution **/
+ if (!substitute(&text, "s/Perl/C/")) {
+ printf("substitute: s/Perl/C...No substitution made.\n\n");
+ }
+
+ SvREFCNT_dec(text);
+ PL_perl_destruct_level = 1;
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
+
+which produces the output (again, long lines have been wrapped here)
+
+ match: Text contains the word 'quarter'.
+
+ match: Text doesn't contain the word 'eighth'.
+
+ matches: m/(wi..)/g found 2 matches...
+ match: will
+ match: with
+
+ substitute: s/[aeiou]//gi...139 substitutions made.
+ Now text is: Whn h s t cnvnnc str nd th bll cms t sm mnt lk 76 cnts,
+ Mynrd s wr tht thr s smthng h *shld* d, smthng tht wll nbl hm t gt bck
+ qrtr, bt h hs n d *wht*. H fmbls thrgh hs rd sqzy chngprs nd gvs th by
+ thr xtr pnns wth hs dllr, hpng tht h mght lck nt th crrct mnt. Th by gvs
+ hm bck tw f hs wn pnns nd thn th bg shny qrtr tht s hs prz. -RCHH
+
+ substitute: s/Perl/C...No substitution made.
+
+=head2 Fiddling with the Perl stack from your C program
+
+When trying to explain stacks, most computer science textbooks mumble
+something about spring-loaded columns of cafeteria plates: the last
+thing you pushed on the stack is the first thing you pop off. That'll
+do for our purposes: your C program will push some arguments onto "the Perl
+stack", shut its eyes while some magic happens, and then pop the
+results--the return value of your Perl subroutine--off the stack.
+
+First you'll need to know how to convert between C types and Perl
+types, with newSViv() and sv_setnv() and newAV() and all their
+friends. They're described in L<perlguts> and L<perlapi>.
+
+Then you'll need to know how to manipulate the Perl stack. That's
+described in L<perlcall>.
+
+Once you've understood those, embedding Perl in C is easy.
+
+Because C has no builtin function for integer exponentiation, let's
+make Perl's ** operator available to it (this is less useful than it
+sounds, because Perl implements ** with C's I<pow()> function). First
+I'll create a stub exponentiation function in I<power.pl>:
+
+ sub expo {
+ my ($a, $b) = @_;
+ return $a ** $b;
+ }
+
+Now I'll create a C program, I<power.c>, with a function
+I<PerlPower()> that contains all the perlguts necessary to push the
+two arguments into I<expo()> and to pop the return value out. Take a
+deep breath...
+
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ static PerlInterpreter *my_perl;
+
+ static void
+ PerlPower(int a, int b)
+ {
+ dSP; /* initialize stack pointer */
+ ENTER; /* everything created after here */
+ SAVETMPS; /* ...is a temporary variable. */
+ PUSHMARK(SP); /* remember the stack pointer */
+ XPUSHs(sv_2mortal(newSViv(a))); /* push the base onto the stack */
+ XPUSHs(sv_2mortal(newSViv(b))); /* push the exponent onto stack */
+ PUTBACK; /* make local stack pointer global */
+ call_pv("expo", G_SCALAR); /* call the function */
+ SPAGAIN; /* refresh stack pointer */
+ /* pop the return value from stack */
+ printf ("%d to the %dth power is %d.\n", a, b, POPi);
+ PUTBACK;
+ FREETMPS; /* free that return value */
+ LEAVE; /* ...and the XPUSHed "mortal" args.*/
+ }
+
+ int main (int argc, char **argv, char **env)
+ {
+ char *my_argv[] = { "", "power.pl" };
+
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct( my_perl );
+
+ perl_parse(my_perl, NULL, 2, my_argv, (char **)NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ perl_run(my_perl);
+
+ PerlPower(3, 4); /*** Compute 3 ** 4 ***/
+
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
+
+
+
+Compile and run:
+
+ % cc -o power power.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+ % power
+ 3 to the 4th power is 81.
+
+=head2 Maintaining a persistent interpreter
+
+When developing interactive and/or potentially long-running
+applications, it's a good idea to maintain a persistent interpreter
+rather than allocating and constructing a new interpreter multiple
+times. The major reason is speed: since Perl will only be loaded into
+memory once.
+
+However, you have to be more cautious with namespace and variable
+scoping when using a persistent interpreter. In previous examples
+we've been using global variables in the default package C<main>. We
+knew exactly what code would be run, and assumed we could avoid
+variable collisions and outrageous symbol table growth.
+
+Let's say your application is a server that will occasionally run Perl
+code from some arbitrary file. Your server has no way of knowing what
+code it's going to run. Very dangerous.
+
+If the file is pulled in by C<perl_parse()>, compiled into a newly
+constructed interpreter, and subsequently cleaned out with
+C<perl_destruct()> afterwards, you're shielded from most namespace
+troubles.
+
+One way to avoid namespace collisions in this scenario is to translate
+the filename into a guaranteed-unique package name, and then compile
+the code into that package using L<perlfunc/eval>. In the example
+below, each file will only be compiled once. Or, the application
+might choose to clean out the symbol table associated with the file
+after it's no longer needed. Using L<perlapi/call_argv>, We'll
+call the subroutine C<Embed::Persistent::eval_file> which lives in the
+file C<persistent.pl> and pass the filename and boolean cleanup/cache
+flag as arguments.
+
+Note that the process will continue to grow for each file that it
+uses. In addition, there might be C<AUTOLOAD>ed subroutines and other
+conditions that cause Perl's symbol table to grow. You might want to
+add some logic that keeps track of the process size, or restarts
+itself after a certain number of requests, to ensure that memory
+consumption is minimized. You'll also want to scope your variables
+with L<perlfunc/my> whenever possible.
+
+
+ package Embed::Persistent;
+ #persistent.pl
+
+ use strict;
+ our %Cache;
+ use Symbol qw(delete_package);
+
+ sub valid_package_name {
+ my($string) = @_;
+ $string =~ s/([^A-Za-z0-9\/])/sprintf("_%2x",unpack("C",$1))/eg;
+ # second pass only for words starting with a digit
+ $string =~ s|/(\d)|sprintf("/_%2x",unpack("C",$1))|eg;
+
+ # Dress it up as a real package name
+ $string =~ s|/|::|g;
+ return "Embed" . $string;
+ }
+
+ sub eval_file {
+ my($filename, $delete) = @_;
+ my $package = valid_package_name($filename);
+ my $mtime = -M $filename;
+ if(defined $Cache{$package}{mtime}
+ &&
+ $Cache{$package}{mtime} <= $mtime)
+ {
+ # we have compiled this subroutine already,
+ # it has not been updated on disk, nothing left to do
+ print STDERR "already compiled $package->handler\n";
+ }
+ else {
+ local *FH;
+ open FH, $filename or die "open '$filename' $!";
+ local($/) = undef;
+ my $sub = <FH>;
+ close FH;
+
+ #wrap the code into a subroutine inside our unique package
+ my $eval = qq{package $package; sub handler { $sub; }};
+ {
+ # hide our variables within this block
+ my($filename,$mtime,$package,$sub);
+ eval $eval;
+ }
+ die $@ if $@;
+
+ #cache it unless we're cleaning out each time
+ $Cache{$package}{mtime} = $mtime unless $delete;
+ }
+
+ eval {$package->handler;};
+ die $@ if $@;
+
+ delete_package($package) if $delete;
+
+ #take a look if you want
+ #print Devel::Symdump->rnew($package)->as_string, $/;
+ }
+
+ 1;
+
+ __END__
+
+ /* persistent.c */
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ /* 1 = clean out filename's symbol table after each request, 0 = don't */
+ #ifndef DO_CLEAN
+ #define DO_CLEAN 0
+ #endif
+
+ #define BUFFER_SIZE 1024
+
+ static PerlInterpreter *my_perl = NULL;
+
+ int
+ main(int argc, char **argv, char **env)
+ {
+ char *embedding[] = { "", "persistent.pl" };
+ char *args[] = { "", DO_CLEAN, NULL };
+ char filename[BUFFER_SIZE];
+ int exitstatus = 0;
+
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ if((my_perl = perl_alloc()) == NULL) {
+ fprintf(stderr, "no memory!");
+ exit(1);
+ }
+ perl_construct(my_perl);
+
+ PL_origalen = 1; /* don't let $0 assignment update the proctitle or embedding[0] */
+ exitstatus = perl_parse(my_perl, NULL, 2, embedding, NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ if(!exitstatus) {
+ exitstatus = perl_run(my_perl);
+
+ while(printf("Enter file name: ") &&
+ fgets(filename, BUFFER_SIZE, stdin)) {
+
+ filename[strlen(filename)-1] = '\0'; /* strip \n */
+ /* call the subroutine, passing it the filename as an argument */
+ args[0] = filename;
+ call_argv("Embed::Persistent::eval_file",
+ G_DISCARD | G_EVAL, args);
+
+ /* check $@ */
+ if(SvTRUE(ERRSV))
+ fprintf(stderr, "eval error: %s\n", SvPV_nolen(ERRSV));
+ }
+ }
+
+ PL_perl_destruct_level = 0;
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ exit(exitstatus);
+ }
+
+Now compile:
+
+ % cc -o persistent persistent.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+Here's an example script file:
+
+ #test.pl
+ my $string = "hello";
+ foo($string);
+
+ sub foo {
+ print "foo says: @_\n";
+ }
+
+Now run:
+
+ % persistent
+ Enter file name: test.pl
+ foo says: hello
+ Enter file name: test.pl
+ already compiled Embed::test_2epl->handler
+ foo says: hello
+ Enter file name: ^C
+
+=head2 Execution of END blocks
+
+Traditionally END blocks have been executed at the end of the perl_run.
+This causes problems for applications that never call perl_run. Since
+perl 5.7.2 you can specify C<PL_exit_flags |= PERL_EXIT_DESTRUCT_END>
+to get the new behaviour. This also enables the running of END blocks if
+the perl_parse fails and C<perl_destruct> will return the exit value.
+
+=head2 $0 assignments
+
+When a perl script assigns a value to $0 then the perl runtime will
+try to make this value show up as the program name reported by "ps" by
+updating the memory pointed to by the argv passed to perl_parse() and
+also calling API functions like setproctitle() where available. This
+behaviour might not be appropriate when embedding perl and can be
+disabled by assigning the value C<1> to the variable C<PL_origalen>
+before perl_parse() is called.
+
+The F<persistent.c> example above is for instance likely to segfault
+when $0 is assigned to if the C<PL_origalen = 1;> assignment is
+removed. This because perl will try to write to the read only memory
+of the C<embedding[]> strings.
+
+=head2 Maintaining multiple interpreter instances
+
+Some rare applications will need to create more than one interpreter
+during a session. Such an application might sporadically decide to
+release any resources associated with the interpreter.
+
+The program must take care to ensure that this takes place I<before>
+the next interpreter is constructed. By default, when perl is not
+built with any special options, the global variable
+C<PL_perl_destruct_level> is set to C<0>, since extra cleaning isn't
+usually needed when a program only ever creates a single interpreter
+in its entire lifetime.
+
+Setting C<PL_perl_destruct_level> to C<1> makes everything squeaky clean:
+
+ while(1) {
+ ...
+ /* reset global variables here with PL_perl_destruct_level = 1 */
+ PL_perl_destruct_level = 1;
+ perl_construct(my_perl);
+ ...
+ /* clean and reset _everything_ during perl_destruct */
+ PL_perl_destruct_level = 1;
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ ...
+ /* let's go do it again! */
+ }
+
+When I<perl_destruct()> is called, the interpreter's syntax parse tree
+and symbol tables are cleaned up, and global variables are reset. The
+second assignment to C<PL_perl_destruct_level> is needed because
+perl_construct resets it to C<0>.
+
+Now suppose we have more than one interpreter instance running at the
+same time. This is feasible, but only if you used the Configure option
+C<-Dusemultiplicity> or the options C<-Dusethreads -Duseithreads> when
+building perl. By default, enabling one of these Configure options
+sets the per-interpreter global variable C<PL_perl_destruct_level> to
+C<1>, so that thorough cleaning is automatic and interpreter variables
+are initialized correctly. Even if you don't intend to run two or
+more interpreters at the same time, but to run them sequentially, like
+in the above example, it is recommended to build perl with the
+C<-Dusemultiplicity> option otherwise some interpreter variables may
+not be initialized correctly between consecutive runs and your
+application may crash.
+
+See also L<perlxs/Thread-aware system interfaces>.
+
+Using C<-Dusethreads -Duseithreads> rather than C<-Dusemultiplicity>
+is more appropriate if you intend to run multiple interpreters
+concurrently in different threads, because it enables support for
+linking in the thread libraries of your system with the interpreter.
+
+Let's give it a try:
+
+
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ /* we're going to embed two interpreters */
+ /* we're going to embed two interpreters */
+
+ #define SAY_HELLO "-e", "print qq(Hi, I'm $^X\n)"
+
+ int main(int argc, char **argv, char **env)
+ {
+ PerlInterpreter *one_perl, *two_perl;
+ char *one_args[] = { "one_perl", SAY_HELLO };
+ char *two_args[] = { "two_perl", SAY_HELLO };
+
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ one_perl = perl_alloc();
+ two_perl = perl_alloc();
+
+ PERL_SET_CONTEXT(one_perl);
+ perl_construct(one_perl);
+ PERL_SET_CONTEXT(two_perl);
+ perl_construct(two_perl);
+
+ PERL_SET_CONTEXT(one_perl);
+ perl_parse(one_perl, NULL, 3, one_args, (char **)NULL);
+ PERL_SET_CONTEXT(two_perl);
+ perl_parse(two_perl, NULL, 3, two_args, (char **)NULL);
+
+ PERL_SET_CONTEXT(one_perl);
+ perl_run(one_perl);
+ PERL_SET_CONTEXT(two_perl);
+ perl_run(two_perl);
+
+ PERL_SET_CONTEXT(one_perl);
+ perl_destruct(one_perl);
+ PERL_SET_CONTEXT(two_perl);
+ perl_destruct(two_perl);
+
+ PERL_SET_CONTEXT(one_perl);
+ perl_free(one_perl);
+ PERL_SET_CONTEXT(two_perl);
+ perl_free(two_perl);
+ PERL_SYS_TERM();
+ }
+
+Note the calls to PERL_SET_CONTEXT(). These are necessary to initialize
+the global state that tracks which interpreter is the "current" one on
+the particular process or thread that may be running it. It should
+always be used if you have more than one interpreter and are making
+perl API calls on both interpreters in an interleaved fashion.
+
+PERL_SET_CONTEXT(interp) should also be called whenever C<interp> is
+used by a thread that did not create it (using either perl_alloc(), or
+the more esoteric perl_clone()).
+
+Compile as usual:
+
+ % cc -o multiplicity multiplicity.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+Run it, Run it:
+
+ % multiplicity
+ Hi, I'm one_perl
+ Hi, I'm two_perl
+
+=head2 Using Perl modules, which themselves use C libraries, from your C program
+
+If you've played with the examples above and tried to embed a script
+that I<use()>s a Perl module (such as I<Socket>) which itself uses a C or C++ library,
+this probably happened:
+
+
+ Can't load module Socket, dynamic loading not available in this perl.
+ (You may need to build a new perl executable which either supports
+ dynamic loading or has the Socket module statically linked into it.)
+
+
+What's wrong?
+
+Your interpreter doesn't know how to communicate with these extensions
+on its own. A little glue will help. Up until now you've been
+calling I<perl_parse()>, handing it NULL for the second argument:
+
+ perl_parse(my_perl, NULL, argc, my_argv, NULL);
+
+That's where the glue code can be inserted to create the initial contact between
+Perl and linked C/C++ routines. Let's take a look some pieces of I<perlmain.c>
+to see how Perl does this:
+
+ static void xs_init (pTHX);
+
+ EXTERN_C void boot_DynaLoader (pTHX_ CV* cv);
+ EXTERN_C void boot_Socket (pTHX_ CV* cv);
+
+
+ EXTERN_C void
+ xs_init(pTHX)
+ {
+ char *file = __FILE__;
+ /* DynaLoader is a special case */
+ newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
+ newXS("Socket::bootstrap", boot_Socket, file);
+ }
+
+Simply put: for each extension linked with your Perl executable
+(determined during its initial configuration on your
+computer or when adding a new extension),
+a Perl subroutine is created to incorporate the extension's
+routines. Normally, that subroutine is named
+I<Module::bootstrap()> and is invoked when you say I<use Module>. In
+turn, this hooks into an XSUB, I<boot_Module>, which creates a Perl
+counterpart for each of the extension's XSUBs. Don't worry about this
+part; leave that to the I<xsubpp> and extension authors. If your
+extension is dynamically loaded, DynaLoader creates I<Module::bootstrap()>
+for you on the fly. In fact, if you have a working DynaLoader then there
+is rarely any need to link in any other extensions statically.
+
+
+Once you have this code, slap it into the second argument of I<perl_parse()>:
+
+
+ perl_parse(my_perl, xs_init, argc, my_argv, NULL);
+
+
+Then compile:
+
+ % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+
+ % interp
+ use Socket;
+ use SomeDynamicallyLoadedModule;
+
+ print "Now I can use extensions!\n"'
+
+B<ExtUtils::Embed> can also automate writing the I<xs_init> glue code.
+
+ % perl -MExtUtils::Embed -e xsinit -- -o perlxsi.c
+ % cc -c perlxsi.c `perl -MExtUtils::Embed -e ccopts`
+ % cc -c interp.c `perl -MExtUtils::Embed -e ccopts`
+ % cc -o interp perlxsi.o interp.o `perl -MExtUtils::Embed -e ldopts`
+
+Consult L<perlxs>, L<perlguts>, and L<perlapi> for more details.
+
+=head1 Embedding Perl under Win32
+
+In general, all of the source code shown here should work unmodified under
+Windows.
+
+However, there are some caveats about the command-line examples shown.
+For starters, backticks won't work under the Win32 native command shell.
+The ExtUtils::Embed kit on CPAN ships with a script called
+B<genmake>, which generates a simple makefile to build a program from
+a single C source file. It can be used like this:
+
+ C:\ExtUtils-Embed\eg> perl genmake interp.c
+ C:\ExtUtils-Embed\eg> nmake
+ C:\ExtUtils-Embed\eg> interp -e "print qq{I'm embedded in Win32!\n}"
+
+You may wish to use a more robust environment such as the Microsoft
+Developer Studio. In this case, run this to generate perlxsi.c:
+
+ perl -MExtUtils::Embed -e xsinit
+
+Create a new project and Insert -> Files into Project: perlxsi.c,
+perl.lib, and your own source files, e.g. interp.c. Typically you'll
+find perl.lib in B<C:\perl\lib\CORE>, if not, you should see the
+B<CORE> directory relative to C<perl -V:archlib>. The studio will
+also need this path so it knows where to find Perl include files.
+This path can be added via the Tools -> Options -> Directories menu.
+Finally, select Build -> Build interp.exe and you're ready to go.
+
+=head1 Hiding Perl_
+
+If you completely hide the short forms of the Perl public API,
+add -DPERL_NO_SHORT_NAMES to the compilation flags. This means that
+for example instead of writing
+
+ warn("%d bottles of beer on the wall", bottlecount);
+
+you will have to write the explicit full form
+
+ Perl_warn(aTHX_ "%d bottles of beer on the wall", bottlecount);
+
+(See L<perlguts/Background and PERL_IMPLICIT_CONTEXT for the explanation
+of the C<aTHX_>.> ) Hiding the short forms is very useful for avoiding
+all sorts of nasty (C preprocessor or otherwise) conflicts with other
+software packages (Perl defines about 2400 APIs with these short names,
+take or leave few hundred, so there certainly is room for conflict.)
+
+=head1 MORAL
+
+You can sometimes I<write faster code> in C, but
+you can always I<write code faster> in Perl. Because you can use
+each from the other, combine them as you wish.
+
+
+=head1 AUTHOR
+
+Jon Orwant <F<orwant@media.mit.edu>> and Doug MacEachern
+<F<dougm@covalent.net>>, with small contributions from Tim Bunce, Tom
+Christiansen, Guy Decoux, Hallvard Furuseth, Dov Grobgeld, and Ilya
+Zakharevich.
+
+Doug MacEachern has an article on embedding in Volume 1, Issue 4 of
+The Perl Journal ( http://www.tpj.com/ ). Doug is also the developer of the
+most widely-used Perl embedding: the mod_perl system
+(perl.apache.org), which embeds Perl in the Apache web server.
+Oracle, Binary Evolution, ActiveState, and Ben Sugars's nsapi_perl
+have used this model for Oracle, Netscape and Internet Information
+Server Perl plugins.
+
+=head1 COPYRIGHT
+
+Copyright (C) 1995, 1996, 1997, 1998 Doug MacEachern and Jon Orwant. All
+Rights Reserved.
+
+Permission is granted to make and distribute verbatim copies of this
+documentation provided the copyright notice and this permission notice are
+preserved on all copies.
+
+Permission is granted to copy and distribute modified versions of this
+documentation under the conditions for verbatim copying, provided also
+that they are marked clearly as modified versions, that the authors'
+names and title are unchanged (though subtitles and additional
+authors' names may be added), and that the entire resulting derived
+work is distributed under the terms of a permission notice identical
+to this one.
+
+Permission is granted to copy and distribute translations of this
+documentation into another language, under the above conditions for
+modified versions.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlepoc.pod b/Master/tlpkg/tlperl/lib/pods/perlepoc.pod
new file mode 100644
index 00000000000..da33725acde
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlepoc.pod
@@ -0,0 +1,154 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+README.epoc - Perl for EPOC
+
+=head1 SYNOPSIS
+
+Perl 5 README file for the EPOC Release 5 operating system.
+
+=head1 INTRODUCTION
+
+EPOC is an OS for palmtops and mobile phones. For more informations look at:
+http://www.symbian.com/
+
+This is a port of perl to the epocemx SDK by Eberhard Mattes, which
+itself uses the SDK by symbian. Essentially epocemx it is a POSIX
+look alike environment for the EPOC OS. For more information look at:
+http://epocemx.sourceforge.net/
+
+perl and epocemx runs on Epoc Release 5 machines: Psion 5mx, 5mx Pro,
+Psion Revo, Psion Netbook and on the Ericsson M128. It may run on Epoc
+Release 3 Hardware (Series 5 classic), too. For more information about
+this hardware please refer to http://www.psion.com/
+
+Vendors which like to have support for their devices are free to send
+me a sample.
+
+=head1 INSTALLING PERL ON EPOC
+
+You can download a ready-to-install version from
+http://www.oflebbe.de/perl/perl5.html
+
+You will need at least ~6MB free space in order to install and run perl.
+
+Please install the emxusr.sis package from
+http://epocemx.sourceforge.net/ first.
+
+Install perl.sis on the EPOC machine. If you do not know how to do
+that, consult your PsiWin documentation.
+
+Perl itself and its standard library is using 4 MB disk space.
+Unicode support and some other modules are left out. (For details,
+please look into epoc/createpkg.pl). If you like to use these modules,
+you are free to copy them from a current perl release.
+
+=head1 STARTING PERL ON EPOC
+
+Please use the epocemx shell to start perl. perl integrates with the
+conventions of epocemx.
+
+=head2 Features of Perl on Epoc
+
+The built-in function EPOC::getcwd returns the current directory.
+
+=head2 Restrictions of Perl on Epoc
+
+Features are left out, because of restrictions of the POSIX support in
+EPOC:
+
+=over 4
+
+=item *
+
+socket IO is only implemented poorly. You can only use sysread and
+syswrite on them. The commands read, write, print, <> do not work for
+sockets. This may change iff epocemx supports sockets.
+
+=item *
+
+kill, alarm and signals. Do not try to use them. This may be
+impossible to implement on EPOC.
+
+=item *
+
+select is missing.
+
+=item *
+
+binmode does not exist. (No CR LF to LF translation for text files)
+
+=item *
+
+EPOC does not handle the notion of current drive and current
+directory very well (i.e. not at all, but it tries hard to emulate
+one). See PATH.
+
+=item *
+
+Heap is limited to 4MB.
+
+=item *
+
+Dynamic loading is not implemented.
+
+=back
+
+=head2 Compiling Perl 5 on the EPOC cross compiling environment
+
+Sorry, this is far too short.
+
+=over 4
+
+=item *
+
+You will need the epocemx SDK from Eberhard Mattes.
+
+=item *
+
+Get the Perl sources from your nearest CPAN site.
+
+=item *
+
+Unpack the sources.
+
+=item *
+
+Build a native perl from this sources... Make sure to save the
+miniperl executable as miniperl.native.
+
+Start again from scratch
+
+ cp epoc/* .
+ ./Configure -S
+ make
+ cp miniperl.native miniperl
+ touch miniperl.exe
+ make
+ perl createpkg.pl
+
+ emxsis perl.pkg perl.sis
+
+=back
+
+=head1 SUPPORT STATUS OF PERL ON EPOC
+
+I'm offering this port "as is". You can ask me questions, but I can't
+guarantee I'll be able to answer them. Since the port to epocemx is
+quite new, please check the web for updates first.
+
+Very special thanks to Eberhard Mattes for epocemx.
+
+=head1 AUTHOR
+
+Olaf Flebbe <olaf@oflebbe.de>
+http://www.oflebbe.de/perl/perl5.html
+
+=head1 LAST UPDATE
+
+2003-01-18
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq.pod
new file mode 100644
index 00000000000..6eb7d2520aa
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq.pod
@@ -0,0 +1,1444 @@
+=head1 NAME
+
+perlfaq - frequently asked questions about Perl
+
+=head1 DESCRIPTION
+
+The perlfaq comprises several documents that answer the most commonly
+asked questions about Perl and Perl programming. It's divided by topic
+into nine major sections outlined in this document.
+
+=head2 Where to get the perlfaq
+
+The perlfaq comes with the standard Perl distribution, so if you have Perl
+you should have the perlfaq. You should also have the C<perldoc> tool
+that lets you read the L<perlfaq>:
+
+ $ perldoc perlfaq
+
+Besides your local system, you can find the perlfaq on the web, including
+at http://perldoc.perl.org/ .
+
+The perlfaq is an evolving document and you can read the latest version
+at http://faq.perl.org/ . The perlfaq-workers periodically post extracts
+of the latest perlfaq to comp.lang.perl.misc.
+
+You can view the source tree at https://github.com/briandfoy/perlfaq
+(which is outside of the main Perl source tree). The git repository
+notes all changes to the FAQ and holds the latest version of the
+working documents and may vary significantly from the version
+distributed with the latest version of Perl. Check the repository
+before sending your corrections.
+
+=head2 How to contribute to the perlfaq
+
+You can mail corrections, additions, and suggestions to
+C<< <perlfaq-workers AT perl DOT org> >>. The perlfaq volunteers use this
+address to coordinate their efforts and track the perlfaq development.
+They appreciate your contributions to the FAQ but do not have time to
+provide individual help, so don't use this address to ask FAQs.
+
+The perlfaq server posts extracts of the perlfaq to that newsgroup every
+6 hours (or so), and the community of volunteers reviews and updates the
+answers. If you'd like to help review and update the answers, check out
+comp.lang.perl.misc.
+
+You can also fork the git repository for the perlfaq and send a pull
+request so the main repository can pull your changes. The repository
+is at:
+
+ https://github.com/briandfoy/perlfaq
+
+=head2 What will happen if you mail your Perl programming problems to the authors?
+
+The perlfaq-workers like to keep all traffic on the perlfaq-workers list
+so that everyone can see the work being done (and the work that needs to
+be done). The mailing list serves as an official record. If you email the
+authors or maintainers directly, you'll probably get a reply asking you
+to post to the mailing list. If you don't get a reply, it probably means
+that the person never saw the message or didn't have time to deal with
+it. Posting to the list allows the volunteers with time to deal with it
+when others are busy.
+
+If you have a question that isn't in the FAQ and you would like help with
+it, try the resources in L<perlfaq2>.
+
+=head1 CREDITS
+
+Tom Christiansen wrote the original perlfaq then expanded it with the
+help of Nat Torkington. The perlfaq-workers maintain current document
+and the dezinens of comp.lang.perl.misc regularly review and update the
+FAQ. Several people have contributed answers, corrections, and comments,
+and the perlfaq notes those contributions wherever appropriate.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Tom Christainsen wrote the original version of this document.
+brian d foy C<< <bdfoy@cpan.org> >> wrote this version. See the
+individual perlfaq documents for additional copyright information.
+
+This document is available under the same terms as Perl itself. Code
+examples in all the perlfaq documents are in the public domain. Use
+them as you see fit (and at your own risk with no warranty from anyone).
+
+=head1 Table of Contents
+
+=over 4
+
+=item perlfaq - this document
+
+=item perlfaq1 - General Questions About Perl
+
+=item perlfaq2 - Obtaining and Learning about Perl
+
+=item perlfaq3 - Programming Tools
+
+=item perlfaq4 - Data Manipulation
+
+=item perlfaq5 - Files and Formats
+
+=item perlfaq6 - Regular Expressions
+
+=item perlfaq7 - General Perl Language Issues
+
+=item perlfaq8 - System Interaction
+
+=item perlfaq9 - Networking
+
+=back
+
+=head1 The Questions
+
+=head2 L<perlfaq1>: General Questions About Perl
+
+Very general, high-level questions about Perl.
+
+=over 4
+
+=item *
+
+What is Perl?
+
+=item *
+
+Who supports Perl? Who develops it? Why is it free?
+
+=item *
+
+Which version of Perl should I use?
+
+=item *
+
+What are Perl 4, Perl 5, or Perl 6?
+
+=item *
+
+What was Ponie?
+
+=item *
+
+What is Perl 6?
+
+=item *
+
+How stable is Perl?
+
+=item *
+
+Is Perl difficult to learn?
+
+=item *
+
+How does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl?
+
+=item *
+
+Can I do [task] in Perl?
+
+=item *
+
+When shouldn't I program in Perl?
+
+=item *
+
+What's the difference between "perl" and "Perl"?
+
+=item *
+
+Is it a Perl program or a Perl script?
+
+=item *
+
+What is a JAPH?
+
+=item *
+
+Where can I get a list of Larry Wall witticisms?
+
+=item *
+
+How can I convince others to use Perl?
+
+=back
+
+
+=head2 L<perlfaq2>: Obtaining and Learning about Perl
+
+Where to find source and documentation for Perl, support, and related matters.
+
+=over 4
+
+=item *
+
+What machines support perl? Where do I get it?
+
+=item *
+
+How can I get a binary version of perl?
+
+=item *
+
+I don't have a C compiler. How can I build my own Perl interpreter?
+
+=item *
+
+I copied the perl binary from one machine to another, but scripts don't work.
+
+=item *
+
+I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work?
+
+=item *
+
+What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean?
+
+=item *
+
+Is there an ISO or ANSI certified version of Perl?
+
+=item *
+
+Where can I get information on Perl?
+
+=item *
+
+What are the Perl newsgroups on Usenet? Where do I post questions?
+
+=item *
+
+Where should I post source code?
+
+=item *
+
+Perl Books
+
+=item *
+
+Which magazines have Perl content?
+
+=item *
+
+What mailing lists are there for Perl?
+
+=item *
+
+Where are the archives for comp.lang.perl.misc?
+
+=item *
+
+Where can I buy a commercial version of perl?
+
+=item *
+
+Where do I send bug reports?
+
+=item *
+
+What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org?
+
+=back
+
+
+=head2 L<perlfaq3>: Programming Tools
+
+Programmer tools and programming support.
+
+=over 4
+
+=item *
+
+How do I do (anything)?
+
+=item *
+
+How can I use Perl interactively?
+
+=item *
+
+Is there a Perl shell?
+
+=item *
+
+How do I find which modules are installed on my system?
+
+=item *
+
+How do I debug my Perl programs?
+
+=item *
+
+How do I profile my Perl programs?
+
+=item *
+
+How do I cross-reference my Perl programs?
+
+=item *
+
+Is there a pretty-printer (formatter) for Perl?
+
+=item *
+
+Is there a ctags for Perl?
+
+=item *
+
+Is there an IDE or Windows Perl Editor?
+
+=item *
+
+Where can I get Perl macros for vi?
+
+=item *
+
+Where can I get perl-mode for emacs?
+
+=item *
+
+How can I use curses with Perl?
+
+=item *
+
+How can I write a GUI (X, Tk, Gtk, etc.) in Perl?
+
+=item *
+
+How can I make my Perl program run faster?
+
+=item *
+
+How can I make my Perl program take less memory?
+
+=item *
+
+Is it safe to return a reference to local or lexical data?
+
+=item *
+
+How can I free an array or hash so my program shrinks?
+
+=item *
+
+How can I make my CGI script more efficient?
+
+=item *
+
+How can I hide the source for my Perl program?
+
+=item *
+
+How can I compile my Perl program into byte code or C?
+
+=item *
+
+How can I get C<#!perl> to work on [MS-DOS,NT,...]?
+
+=item *
+
+Can I write useful Perl programs on the command line?
+
+=item *
+
+Why don't Perl one-liners work on my DOS/Mac/VMS system?
+
+=item *
+
+Where can I learn about CGI or Web programming in Perl?
+
+=item *
+
+Where can I learn about object-oriented Perl programming?
+
+=item *
+
+Where can I learn about linking C with Perl?
+
+=item *
+
+I've read perlembed, perlguts, etc., but I can't embed perl in my C program; what am I doing wrong?
+
+=item *
+
+When I tried to run my script, I got this message. What does it mean?
+
+=item *
+
+What's MakeMaker?
+
+=back
+
+
+=head2 L<perlfaq4>: Data Manipulation
+
+Manipulating numbers, dates, strings, arrays, hashes, and miscellaneous data issues.
+
+=over 4
+
+=item *
+
+Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?
+
+=item *
+
+Why is int() broken?
+
+=item *
+
+Why isn't my octal data interpreted correctly?
+
+=item *
+
+Does Perl have a round() function? What about ceil() and floor()? Trig functions?
+
+=item *
+
+How do I convert between numeric representations/bases/radixes?
+
+=item *
+
+Why doesn't & work the way I want it to?
+
+=item *
+
+How do I multiply matrices?
+
+=item *
+
+How do I perform an operation on a series of integers?
+
+=item *
+
+How can I output Roman numerals?
+
+=item *
+
+Why aren't my random numbers random?
+
+=item *
+
+How do I get a random number between X and Y?
+
+=item *
+
+How do I find the day or week of the year?
+
+=item *
+
+How do I find the current century or millennium?
+
+=item *
+
+How can I compare two dates and find the difference?
+
+=item *
+
+How can I take a string and turn it into epoch seconds?
+
+=item *
+
+How can I find the Julian Day?
+
+=item *
+
+How do I find yesterday's date?
+
+=item *
+
+Does Perl have a Year 2000 or 2038 problem? Is Perl Y2K compliant?
+
+=item *
+
+How do I validate input?
+
+=item *
+
+How do I unescape a string?
+
+=item *
+
+How do I remove consecutive pairs of characters?
+
+=item *
+
+How do I expand function calls in a string?
+
+=item *
+
+How do I find matching/nesting anything?
+
+=item *
+
+How do I reverse a string?
+
+=item *
+
+How do I expand tabs in a string?
+
+=item *
+
+How do I reformat a paragraph?
+
+=item *
+
+How can I access or change N characters of a string?
+
+=item *
+
+How do I change the Nth occurrence of something?
+
+=item *
+
+How can I count the number of occurrences of a substring within a string?
+
+=item *
+
+How do I capitalize all the words on one line?
+
+=item *
+
+How can I split a [character] delimited string except when inside [character]?
+
+=item *
+
+How do I strip blank space from the beginning/end of a string?
+
+=item *
+
+How do I pad a string with blanks or pad a number with zeroes?
+
+=item *
+
+How do I extract selected columns from a string?
+
+=item *
+
+How do I find the soundex value of a string?
+
+=item *
+
+How can I expand variables in text strings?
+
+=item *
+
+What's wrong with always quoting "$vars"?
+
+=item *
+
+Why don't my E<lt>E<lt>HERE documents work?
+
+=item *
+
+What is the difference between a list and an array?
+
+=item *
+
+What is the difference between $array[1] and @array[1]?
+
+=item *
+
+How can I remove duplicate elements from a list or array?
+
+=item *
+
+How can I tell whether a certain element is contained in a list or array?
+
+=item *
+
+How do I compute the difference of two arrays? How do I compute the intersection of two arrays?
+
+=item *
+
+How do I test whether two arrays or hashes are equal?
+
+=item *
+
+How do I find the first array element for which a condition is true?
+
+=item *
+
+How do I handle linked lists?
+
+=item *
+
+How do I handle circular lists?
+
+=item *
+
+How do I shuffle an array randomly?
+
+=item *
+
+How do I process/modify each element of an array?
+
+=item *
+
+How do I select a random element from an array?
+
+=item *
+
+How do I permute N elements of a list?
+
+=item *
+
+How do I sort an array by (anything)?
+
+=item *
+
+How do I manipulate arrays of bits?
+
+=item *
+
+Why does defined() return true on empty arrays and hashes?
+
+=item *
+
+How do I process an entire hash?
+
+=item *
+
+How do I merge two hashes?
+
+=item *
+
+What happens if I add or remove keys from a hash while iterating over it?
+
+=item *
+
+How do I look up a hash element by value?
+
+=item *
+
+How can I know how many entries are in a hash?
+
+=item *
+
+How do I sort a hash (optionally by value instead of key)?
+
+=item *
+
+How can I always keep my hash sorted?
+
+=item *
+
+What's the difference between "delete" and "undef" with hashes?
+
+=item *
+
+Why don't my tied hashes make the defined/exists distinction?
+
+=item *
+
+How do I reset an each() operation part-way through?
+
+=item *
+
+How can I get the unique keys from two hashes?
+
+=item *
+
+How can I store a multidimensional array in a DBM file?
+
+=item *
+
+How can I make my hash remember the order I put elements into it?
+
+=item *
+
+Why does passing a subroutine an undefined element in a hash create it?
+
+=item *
+
+How can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays?
+
+=item *
+
+How can I use a reference as a hash key?
+
+=item *
+
+How do I handle binary data correctly?
+
+=item *
+
+How do I determine whether a scalar is a number/whole/integer/float?
+
+=item *
+
+How do I keep persistent data across program calls?
+
+=item *
+
+How do I print out or copy a recursive data structure?
+
+=item *
+
+How do I define methods for every class/object?
+
+=item *
+
+How do I verify a credit card checksum?
+
+=item *
+
+How do I pack arrays of doubles or floats for XS code?
+
+=back
+
+
+=head2 L<perlfaq5>: Files and Formats
+
+I/O and the "f" issues: filehandles, flushing, formats, and footers.
+
+=over 4
+
+=item *
+
+How do I flush/unbuffer an output filehandle? Why must I do this?
+
+=item *
+
+How do I change, delete, or insert a line in a file, or append to the beginning of a file?
+
+=item *
+
+How do I count the number of lines in a file?
+
+=item *
+
+How do I delete the last N lines from a file?
+
+=item *
+
+How can I use Perl's C<-i> option from within a program?
+
+=item *
+
+How can I copy a file?
+
+=item *
+
+How do I make a temporary file name?
+
+=item *
+
+How can I manipulate fixed-record-length files?
+
+=item *
+
+How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles?
+
+=item *
+
+How can I use a filehandle indirectly?
+
+=item *
+
+How can I set up a footer format to be used with write()?
+
+=item *
+
+How can I write() into a string?
+
+=item *
+
+How can I open a filehandle to a string?
+
+=item *
+
+How can I output my numbers with commas added?
+
+=item *
+
+How can I translate tildes (~) in a filename?
+
+=item *
+
+How come when I open a file read-write it wipes it out?
+
+=item *
+
+Why do I sometimes get an "Argument list too long" when I use E<lt>*E<gt>?
+
+=item *
+
+Is there a leak/bug in glob()?
+
+=item *
+
+How can I open a file with a leading ">" or trailing blanks?
+
+=item *
+
+How can I reliably rename a file?
+
+=item *
+
+How can I lock a file?
+
+=item *
+
+Why can't I just open(FH, "E<gt>file.lock")?
+
+=item *
+
+I still don't get locking. I just want to increment the number in the file. How can I do this?
+
+=item *
+
+All I want to do is append a small amount of text to the end of a file. Do I still have to use locking?
+
+=item *
+
+How do I randomly update a binary file?
+
+=item *
+
+How do I get a file's timestamp in perl?
+
+=item *
+
+How do I set a file's timestamp in perl?
+
+=item *
+
+How do I print to more than one file at once?
+
+=item *
+
+How can I read in an entire file all at once?
+
+=item *
+
+How can I read in a file by paragraphs?
+
+=item *
+
+How can I read a single character from a file? From the keyboard?
+
+=item *
+
+How can I tell whether there's a character waiting on a filehandle?
+
+=item *
+
+How do I do a C<tail -f> in perl?
+
+=item *
+
+How do I dup() a filehandle in Perl?
+
+=item *
+
+How do I close a file descriptor by number?
+
+=item *
+
+Why can't I use "C:\temp\foo" in DOS paths? Why doesn't `C:\temp\foo.exe` work?
+
+=item *
+
+Why doesn't glob("*.*") get all the files?
+
+=item *
+
+Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl?
+
+=item *
+
+How do I select a random line from a file?
+
+=item *
+
+Why do I get weird spaces when I print an array of lines?
+
+=item *
+
+How do I traverse a directory tree?
+
+=item *
+
+How do I delete a directory tree?
+
+=item *
+
+How do I copy an entire directory?
+
+=back
+
+
+=head2 L<perlfaq6>: Regular Expressions
+
+This section is surprisingly small because the rest of the FAQ is littered with answers involving regular expressions. For example, decoding a URL and checking whether something is a number are handled with regular expressions, but those answers are found elsewhere in this document (in L<perlfaq9>: "How do I decode or create those %-encodings on the web" and L<perlfaq4>: "How do I determine whether a scalar is a number/whole/integer/float", to be precise).
+
+=over 4
+
+=item *
+
+How can I hope to use regular expressions without creating illegible and unmaintainable code?
+
+=item *
+
+I'm having trouble matching over more than one line. What's wrong?
+
+=item *
+
+How can I pull out lines between two patterns that are themselves on different lines?
+
+=item *
+
+How do I match XML, HTML, or other nasty, ugly things with a regex?
+
+=item *
+
+I put a regular expression into $/ but it didn't work. What's wrong?
+
+=item *
+
+How do I substitute case insensitively on the LHS while preserving case on the RHS?
+
+=item *
+
+How can I make C<\w> match national character sets?
+
+=item *
+
+How can I match a locale-smart version of C</[a-zA-Z]/>?
+
+=item *
+
+How can I quote a variable to use in a regex?
+
+=item *
+
+What is C</o> really for?
+
+=item *
+
+How do I use a regular expression to strip C style comments from a file?
+
+=item *
+
+Can I use Perl regular expressions to match balanced text?
+
+=item *
+
+What does it mean that regexes are greedy? How can I get around it?
+
+=item *
+
+How do I process each word on each line?
+
+=item *
+
+How can I print out a word-frequency or line-frequency summary?
+
+=item *
+
+How can I do approximate matching?
+
+=item *
+
+How do I efficiently match many regular expressions at once?
+
+=item *
+
+Why don't word-boundary searches with C<\b> work for me?
+
+=item *
+
+Why does using $&, $`, or $' slow my program down?
+
+=item *
+
+What good is C<\G> in a regular expression?
+
+=item *
+
+Are Perl regexes DFAs or NFAs? Are they POSIX compliant?
+
+=item *
+
+What's wrong with using grep in a void context?
+
+=item *
+
+How can I match strings with multibyte characters?
+
+=item *
+
+How do I match a regular expression that's in a variable?
+
+=back
+
+
+=head2 L<perlfaq7>: General Perl Language Issues
+
+General Perl language issues that don't clearly fit into any of the other sections.
+
+=over 4
+
+=item *
+
+Can I get a BNF/yacc/RE for the Perl language?
+
+=item *
+
+What are all these $@%&* punctuation signs, and how do I know when to use them?
+
+=item *
+
+Do I always/never have to quote my strings or use semicolons and commas?
+
+=item *
+
+How do I skip some return values?
+
+=item *
+
+How do I temporarily block warnings?
+
+=item *
+
+What's an extension?
+
+=item *
+
+Why do Perl operators have different precedence than C operators?
+
+=item *
+
+How do I declare/create a structure?
+
+=item *
+
+How do I create a module?
+
+=item *
+
+How do I adopt or take over a module already on CPAN?
+
+=item *
+
+How do I create a class?
+
+=item *
+
+How can I tell if a variable is tainted?
+
+=item *
+
+What's a closure?
+
+=item *
+
+What is variable suicide and how can I prevent it?
+
+=item *
+
+How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}?
+
+=item *
+
+How do I create a static variable?
+
+=item *
+
+What's the difference between dynamic and lexical (static) scoping? Between local() and my()?
+
+=item *
+
+How can I access a dynamic variable while a similarly named lexical is in scope?
+
+=item *
+
+What's the difference between deep and shallow binding?
+
+=item *
+
+Why doesn't "my($foo) = E<lt>FILEE<gt>;" work right?
+
+=item *
+
+How do I redefine a builtin function, operator, or method?
+
+=item *
+
+What's the difference between calling a function as &foo and foo()?
+
+=item *
+
+How do I create a switch or case statement?
+
+=item *
+
+How can I catch accesses to undefined variables, functions, or methods?
+
+=item *
+
+Why can't a method included in this same file be found?
+
+=item *
+
+How can I find out my current or calling package?
+
+=item *
+
+How can I comment out a large block of Perl code?
+
+=item *
+
+How do I clear a package?
+
+=item *
+
+How can I use a variable as a variable name?
+
+=item *
+
+What does "bad interpreter" mean?
+
+=back
+
+
+=head2 L<perlfaq8>: System Interaction
+
+This section of the Perl FAQ covers questions involving operating system interaction. Topics include interprocess communication (IPC), control over the user-interface (keyboard, screen and pointing devices), and most anything else not related to data manipulation. Read the FAQs and documentation specific to the port of perl to your operating system (eg, L<perlvms>, L<perlplan9>, ...). These should contain more detailed information on the vagaries of your perl.
+
+=over 4
+
+=item *
+
+How do I find out which operating system I'm running under?
+
+=item *
+
+How come exec() doesn't return?
+
+=item *
+
+How do I do fancy stuff with the keyboard/screen/mouse?
+
+=item *
+
+How do I print something out in color?
+
+=item *
+
+How do I read just one key without waiting for a return key?
+
+=item *
+
+How do I check whether input is ready on the keyboard?
+
+=item *
+
+How do I clear the screen?
+
+=item *
+
+How do I get the screen size?
+
+=item *
+
+How do I ask the user for a password?
+
+=item *
+
+How do I read and write the serial port?
+
+=item *
+
+How do I decode encrypted password files?
+
+=item *
+
+How do I start a process in the background?
+
+=item *
+
+How do I trap control characters/signals?
+
+=item *
+
+How do I modify the shadow password file on a Unix system?
+
+=item *
+
+How do I set the time and date?
+
+=item *
+
+How can I sleep() or alarm() for under a second?
+
+=item *
+
+How can I measure time under a second?
+
+=item *
+
+How can I do an atexit() or setjmp()/longjmp()? (Exception handling)
+
+=item *
+
+Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean?
+
+=item *
+
+How can I call my system's unique C functions from Perl?
+
+=item *
+
+Where do I get the include files to do ioctl() or syscall()?
+
+=item *
+
+Why do setuid perl scripts complain about kernel problems?
+
+=item *
+
+How can I open a pipe both to and from a command?
+
+=item *
+
+Why can't I get the output of a command with system()?
+
+=item *
+
+How can I capture STDERR from an external command?
+
+=item *
+
+Why doesn't open() return an error when a pipe open fails?
+
+=item *
+
+What's wrong with using backticks in a void context?
+
+=item *
+
+How can I call backticks without shell processing?
+
+=item *
+
+Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?
+
+=item *
+
+How can I convert my shell script to perl?
+
+=item *
+
+Can I use perl to run a telnet or ftp session?
+
+=item *
+
+How can I write expect in Perl?
+
+=item *
+
+Is there a way to hide perl's command line from programs such as "ps"?
+
+=item *
+
+I {changed directory, modified my environment} in a perl script. How come the change disappeared when I exited the script? How do I get my changes to be visible?
+
+=item *
+
+How do I close a process's filehandle without waiting for it to complete?
+
+=item *
+
+How do I fork a daemon process?
+
+=item *
+
+How do I find out if I'm running interactively or not?
+
+=item *
+
+How do I timeout a slow event?
+
+=item *
+
+How do I set CPU limits?
+
+=item *
+
+How do I avoid zombies on a Unix system?
+
+=item *
+
+How do I use an SQL database?
+
+=item *
+
+How do I make a system() exit on control-C?
+
+=item *
+
+How do I open a file without blocking?
+
+=item *
+
+How do I tell the difference between errors from the shell and perl?
+
+=item *
+
+How do I install a module from CPAN?
+
+=item *
+
+What's the difference between require and use?
+
+=item *
+
+How do I keep my own module/library directory?
+
+=item *
+
+How do I add the directory my program lives in to the module/library search path?
+
+=item *
+
+How do I add a directory to my include path (@INC) at runtime?
+
+=item *
+
+What is socket.ph and where do I get it?
+
+=back
+
+
+=head2 L<perlfaq9>: Networking
+
+Networking, the internet, and a few on the web.
+
+=over 4
+
+=item *
+
+What is the correct form of response from a CGI script?
+
+=item *
+
+My CGI script runs from the command line but not the browser. (500 Server Error)
+
+=item *
+
+How can I get better error messages from a CGI program?
+
+=item *
+
+How do I remove HTML from a string?
+
+=item *
+
+How do I extract URLs?
+
+=item *
+
+How do I download a file from the user's machine? How do I open a file on another machine?
+
+=item *
+
+How do I make an HTML pop-up menu with Perl?
+
+=item *
+
+How do I fetch an HTML file?
+
+=item *
+
+How do I automate an HTML form submission?
+
+=item *
+
+How do I decode or create those %-encodings on the web?
+
+=item *
+
+How do I redirect to another page?
+
+=item *
+
+How do I put a password on my web pages?
+
+=item *
+
+How do I edit my .htpasswd and .htgroup files with Perl?
+
+=item *
+
+How do I make sure users can't enter values into a form that cause my CGI script to do bad things?
+
+=item *
+
+How do I parse a mail header?
+
+=item *
+
+How do I decode a CGI form?
+
+=item *
+
+How do I check a valid mail address?
+
+=item *
+
+How do I decode a MIME/BASE64 string?
+
+=item *
+
+How do I return the user's mail address?
+
+=item *
+
+How do I send mail?
+
+=item *
+
+How do I use MIME to make an attachment to a mail message?
+
+=item *
+
+How do I read mail?
+
+=item *
+
+How do I find out my hostname, domainname, or IP address?
+
+=item *
+
+How do I fetch a news article or the active newsgroups?
+
+=item *
+
+How do I fetch/put an FTP file?
+
+=item *
+
+How can I do RPC in Perl?
+
+=back
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq1.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq1.pod
new file mode 100644
index 00000000000..16f58018049
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq1.pod
@@ -0,0 +1,410 @@
+=head1 NAME
+
+perlfaq1 - General Questions About Perl
+
+=head1 DESCRIPTION
+
+This section of the FAQ answers very general, high-level questions
+about Perl.
+
+=head2 What is Perl?
+
+Perl is a high-level programming language with an eclectic heritage
+written by Larry Wall and a cast of thousands. It derives from the
+ubiquitous C programming language and to a lesser extent from sed,
+awk, the Unix shell, and at least a dozen other tools and languages.
+Perl's process, file, and text manipulation facilities make it
+particularly well-suited for tasks involving quick prototyping, system
+utilities, software tools, system management tasks, database access,
+graphical programming, networking, and world wide web programming.
+These strengths make it especially popular with system administrators
+and CGI script authors, but mathematicians, geneticists, journalists,
+and even managers also use Perl. Maybe you should, too.
+
+=head2 Who supports Perl? Who develops it? Why is it free?
+
+The original culture of the pre-populist Internet and the deeply-held
+beliefs of Perl's author, Larry Wall, gave rise to the free and open
+distribution policy of perl. Perl is supported by its users. The
+core, the standard Perl library, the optional modules, and the
+documentation you're reading now were all written by volunteers. See
+the personal note at the end of the README file in the perl source
+distribution for more details. See L<perlhist> (new as of 5.005)
+for Perl's milestone releases.
+
+In particular, the core development team (known as the Perl Porters)
+are a rag-tag band of highly altruistic individuals committed to
+producing better software for free than you could hope to purchase for
+money. You may snoop on pending developments via the archives at
+http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
+and http://archive.develooper.com/perl5-porters@perl.org/
+or the news gateway nntp://nntp.perl.org/perl.perl5.porters or
+its web interface at http://nntp.perl.org/group/perl.perl5.porters ,
+or read the faq at http://dev.perl.org/perl5/docs/p5p-faq.html ,
+or you can subscribe to the mailing list by sending
+perl5-porters-subscribe@perl.org a subscription request
+(an empty message with no subject is fine).
+
+While the GNU project includes Perl in its distributions, there's no
+such thing as "GNU Perl". Perl is not produced nor maintained by the
+Free Software Foundation. Perl's licensing terms are also more open
+than GNU software's tend to be.
+
+You can get commercial support of Perl if you wish, although for most
+users the informal support will more than suffice. See the answer to
+"Where can I buy a commercial version of perl?" for more information.
+
+=head2 Which version of Perl should I use?
+
+(contributed by brian d foy)
+
+There is often a matter of opinion and taste, and there isn't any one
+answer that fits everyone. In general, you want to use either the current
+stable release, or the stable release immediately prior to that one.
+Currently, those are perl5.10.x and perl5.8.x, respectively.
+
+Beyond that, you have to consider several things and decide which is best
+for you.
+
+=over 4
+
+=item *
+
+If things aren't broken, upgrading perl may break them (or at least issue
+new warnings).
+
+=item *
+
+The latest versions of perl have more bug fixes.
+
+=item *
+
+The Perl community is geared toward supporting the most recent releases,
+so you'll have an easier time finding help for those.
+
+=item *
+
+Versions prior to perl5.004 had serious security problems with buffer
+overflows, and in some cases have CERT advisories (for instance,
+http://www.cert.org/advisories/CA-1997-17.html ).
+
+=item *
+
+The latest versions are probably the least deployed and widely tested, so
+you may want to wait a few months after their release and see what
+problems others have if you are risk averse.
+
+=item *
+
+The immediate, previous releases (i.e. perl5.8.x ) are usually maintained
+for a while, although not at the same level as the current releases.
+
+=item *
+
+No one is actively supporting Perl 4. Five years ago it was a dead
+camel carcass (according to this document). Now it's barely a skeleton
+as its whitewashed bones have fractured or eroded.
+
+=item *
+
+There is no Perl 6 release scheduled, but it will be available when
+it's ready. Stay tuned, but don't worry that you'll have to change
+major versions of Perl; no one is going to take Perl 5 away from you.
+
+=item *
+
+There are really two tracks of perl development: a maintenance version
+and an experimental version. The maintenance versions are stable, and
+have an even number as the minor release (i.e. perl5.10.x, where 10 is the
+minor release). The experimental versions may include features that
+don't make it into the stable versions, and have an odd number as the
+minor release (i.e. perl5.9.x, where 9 is the minor release).
+
+=back
+
+
+=head2 What are Perl 4, Perl 5, or Perl 6?
+
+(contributed by brian d foy)
+
+In short, Perl 4 is the past, Perl 5 is the present, and Perl 6 is the
+future.
+
+The number after perl (i.e. the 5 after Perl 5) is the major release
+of the perl interpreter as well as the version of the language. Each
+major version has significant differences that earlier versions cannot
+support.
+
+The current major release of Perl is Perl 5, and was released in 1994.
+It can run scripts from the previous major release, Perl 4 (March 1991),
+but has significant differences. It introduced the concept of references,
+complex data structures, and modules. The Perl 5 interpreter was a
+complete re-write of the previous perl sources.
+
+Perl 6 is the next major version of Perl, but it's still in development
+in both its syntax and design. The work started in 2002 and is still
+ongoing. Many of the most interesting features have shown up in the
+latest versions of Perl 5, and some Perl 5 modules allow you to use some
+Perl 6 syntax in your programs. You can learn more about Perl 6 at
+http://dev.perl.org/perl6/ .
+
+See L<perlhist> for a history of Perl revisions.
+
+=head2 What was Ponie?
+
+(contributed by brian d foy)
+
+Ponie stands for "Perl On the New Internal Engine", started by Arthur
+Bergman from Fotango in 2003, and subsequently run as a project of The
+Perl Foundation. It was abandoned in 2006
+( http://www.nntp.perl.org/group/perl.ponie.dev/487 ).
+
+Instead of using the current Perl internals, Ponie aimed to create a
+new one that would provide a translation path from Perl 5 to Perl 6
+(or anything else that targets Parrot, actually). You would have been
+able to just keep using Perl 5 with Parrot, the virtual machine which
+will compile and run Perl 6 bytecode.
+
+=head2 What is Perl 6?
+
+At The Second O'Reilly Open Source Software Convention, Larry Wall
+announced Perl 6 development would begin in earnest. Perl 6 was an oft
+used term for Chip Salzenberg's project to rewrite Perl in C++ named
+Topaz. However, Topaz provided valuable insights to the next version
+of Perl and its implementation, but was ultimately abandoned.
+
+If you want to learn more about Perl 6, or have a desire to help in
+the crusade to make Perl a better place then read the Perl 6 developers
+page at http://dev.perl.org/perl6/ and get involved.
+
+Perl 6 is not scheduled for release yet, and Perl 5 will still be supported
+for quite awhile after its release. Do not wait for Perl 6 to do whatever
+you need to do.
+
+"We're really serious about reinventing everything that needs reinventing."
+--Larry Wall
+
+=head2 How stable is Perl?
+
+Production releases, which incorporate bug fixes and new functionality,
+are widely tested before release. Since the 5.000 release, we have
+averaged only about one production release per year.
+
+Larry and the Perl development team occasionally make changes to the
+internal core of the language, but all possible efforts are made toward
+backward compatibility. While not quite all Perl 4 scripts run flawlessly
+under Perl 5, an update to perl should nearly never invalidate a program
+written for an earlier version of perl (barring accidental bug fixes
+and the rare new keyword).
+
+=head2 Is Perl difficult to learn?
+
+No, Perl is easy to start learning--and easy to keep learning. It looks
+like most programming languages you're likely to have experience
+with, so if you've ever written a C program, an awk script, a shell
+script, or even a BASIC program, you're already partway there.
+
+Most tasks only require a small subset of the Perl language. One of
+the guiding mottos for Perl development is "there's more than one way
+to do it" (TMTOWTDI, sometimes pronounced "tim toady"). Perl's
+learning curve is therefore shallow (easy to learn) and long (there's
+a whole lot you can do if you really want).
+
+Finally, because Perl is frequently (but not always, and certainly not by
+definition) an interpreted language, you can write your programs and test
+them without an intermediate compilation step, allowing you to experiment
+and test/debug quickly and easily. This ease of experimentation flattens
+the learning curve even more.
+
+Things that make Perl easier to learn: Unix experience, almost any kind
+of programming experience, an understanding of regular expressions, and
+the ability to understand other people's code. If there's something you
+need to do, then it's probably already been done, and a working example is
+usually available for free. Don't forget Perl modules, either.
+They're discussed in Part 3 of this FAQ, along with CPAN, which is
+discussed in Part 2.
+
+=head2 How does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl?
+
+Favorably in some areas, unfavorably in others. Precisely which areas
+are good and bad is often a personal choice, so asking this question
+on Usenet runs a strong risk of starting an unproductive Holy War.
+
+Probably the best thing to do is try to write equivalent code to do a
+set of tasks. These languages have their own newsgroups in which you
+can learn about (but hopefully not argue about) them.
+
+Some comparison documents can be found at http://www.perl.com/doc/FMTEYEWTK/versus/
+if you really can't stop yourself.
+
+=head2 Can I do [task] in Perl?
+
+Perl is flexible and extensible enough for you to use on virtually any
+task, from one-line file-processing tasks to large, elaborate systems.
+For many people, Perl serves as a great replacement for shell scripting.
+For others, it serves as a convenient, high-level replacement for most of
+what they'd program in low-level languages like C or C++. It's ultimately
+up to you (and possibly your management) which tasks you'll use Perl
+for and which you won't.
+
+If you have a library that provides an API, you can make any component
+of it available as just another Perl function or variable using a Perl
+extension written in C or C++ and dynamically linked into your main
+perl interpreter. You can also go the other direction, and write your
+main program in C or C++, and then link in some Perl code on the fly,
+to create a powerful application. See L<perlembed>.
+
+That said, there will always be small, focused, special-purpose
+languages dedicated to a specific problem domain that are simply more
+convenient for certain kinds of problems. Perl tries to be all things
+to all people, but nothing special to anyone. Examples of specialized
+languages that come to mind include prolog and matlab.
+
+=head2 When shouldn't I program in Perl?
+
+When your manager forbids it--but do consider replacing them :-).
+
+Actually, one good reason is when you already have an existing
+application written in another language that's all done (and done
+well), or you have an application language specifically designed for a
+certain task (e.g. prolog, make).
+
+For various reasons, Perl is probably not well-suited for real-time
+embedded systems, low-level operating systems development work like
+device drivers or context-switching code, complex multi-threaded
+shared-memory applications, or extremely large applications. You'll
+notice that perl is not itself written in Perl.
+
+Perl remains fundamentally a dynamically typed language, not
+a statically typed one. You certainly won't be chastised if you don't
+trust nuclear-plant or brain-surgery monitoring code to it. And Larry
+will sleep easier, too--Wall Street programs not withstanding. :-)
+
+=head2 What's the difference between "perl" and "Perl"?
+
+One bit. Oh, you weren't talking ASCII? :-) Larry now uses "Perl" to
+signify the language proper and "perl" the implementation of it, i.e.
+the current interpreter. Hence Tom's quip that "Nothing but perl can
+parse Perl."
+
+Before the first edition of I<Programming perl>, people commonly
+referred to the language as "perl", and its name appeared that way in
+the title because it referred to the interpreter. In the book, Randal
+Schwartz capitalised the language's name to make it stand out better
+when typeset. This convention was adopted by the community, and the
+second edition became I<Programming Perl>, using the capitalized
+version of the name to refer to the language.
+
+You may or may not choose to follow this usage. For example,
+parallelism means "awk and perl" and "Python and Perl" look good, while
+"awk and Perl" and "Python and perl" do not. But never write "PERL",
+because perl is not an acronym, apocryphal folklore and post-facto
+expansions notwithstanding.
+
+=head2 Is it a Perl program or a Perl script?
+
+Larry doesn't really care. He says (half in jest) that "a script is
+what you give the actors. A program is what you give the audience."
+
+Originally, a script was a canned sequence of normally interactive
+commands--that is, a chat script. Something like a UUCP or PPP chat
+script or an expect script fits the bill nicely, as do configuration
+scripts run by a program at its start up, such F<.cshrc> or F<.ircrc>,
+for example. Chat scripts were just drivers for existing programs,
+not stand-alone programs in their own right.
+
+A computer scientist will correctly explain that all programs are
+interpreted and that the only question is at what level. But if you
+ask this question of someone who isn't a computer scientist, they might
+tell you that a I<program> has been compiled to physical machine code
+once and can then be run multiple times, whereas a I<script> must be
+translated by a program each time it's used.
+
+Now that "script" and "scripting" are terms that have been seized by
+unscrupulous or unknowing marketeers for their own nefarious purposes,
+they have begun to take on strange and often pejorative meanings,
+like "non serious" or "not real programming". Consequently, some Perl
+programmers prefer to avoid them altogether.
+
+=head2 What is a JAPH?
+
+(contributed by brian d foy)
+
+JAPH stands for "Just another Perl hacker,", which Randal Schwartz used
+to sign email and usenet messages starting in the late 1980s. He
+previously used the phrase with many subjects ("Just another x hacker,"),
+so to distinguish his JAPH, he started to write them as Perl programs:
+
+ print "Just another Perl hacker,";
+
+Other people picked up on this and started to write clever or obfuscated
+programs to produce the same output, spinning things quickly out of
+control while still providing hours of amusement for their creators and
+readers.
+
+CPAN has several JAPH programs at http://www.cpan.org/misc/japh .
+
+=head2 Where can I get a list of Larry Wall witticisms?
+
+(contributed by brian d foy)
+
+Google "larry wall quotes"! You might even try the "I feel lucky" button.
+:)
+
+Wikiquote has the witticisms from Larry along with their source,
+including his usenet postings and source code comments.
+
+If you want a plain text file, try
+http://www.cpan.org/misc/lwall-quotes.txt.gz .
+
+=head2 How can I convince others to use Perl?
+
+(contributed by brian d foy)
+
+Appeal to their self interest! If Perl is new (and thus scary) to them,
+find something that Perl can do to solve one of their problems. That
+might mean that Perl either saves them something (time, headaches, money)
+or gives them something (flexibility, power, testability).
+
+In general, the benefit of a language is closely related to the skill of
+the people using that language. If you or your team can be more faster,
+better, and stronger through Perl, you'll deliver more value. Remember,
+people often respond better to what they get out of it. If you run
+into resistance, figure out what those people get out of the other
+choice and how Perl might satisfy that requirement.
+
+You don't have to worry about finding or paying for Perl; it's freely
+available and several popular operating systems come with Perl. Community
+support in places such as Perlmonks ( http://www.perlmonks.com )
+and the various Perl mailing lists ( http://lists.perl.org ) means that
+you can usually get quick answers to your problems.
+
+Finally, keep in mind that Perl might not be the right tool for every
+job. You're a much better advocate if your claims are reasonable and
+grounded in reality. Dogmatically advocating anything tends to make
+people discount your message. Be honest about possible disadvantages
+to your choice of Perl since any choice has trade-offs.
+
+You might find these links useful:
+
+=over 4
+
+=item * http://perltraining.com.au/whyperl.html
+
+=item * http://www.perl.org/advocacy/whyperl.html
+
+=back
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples here are in the public
+domain. You are permitted and encouraged to use this code and any
+derivatives thereof in your own programs for fun or for profit as you
+see fit. A simple comment in the code giving credit to the FAQ would
+be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq2.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq2.pod
new file mode 100644
index 00000000000..036df5e9ab8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq2.pod
@@ -0,0 +1,550 @@
+=head1 NAME
+
+perlfaq2 - Obtaining and Learning about Perl
+
+=head1 DESCRIPTION
+
+This section of the FAQ answers questions about where to find
+source and documentation for Perl, support, and
+related matters.
+
+=head2 What machines support perl? Where do I get it?
+
+The standard release of perl (the one maintained by the perl
+development team) is distributed only in source code form. You
+can find the latest releases at http://www.cpan.org/src/README.html .
+
+Perl builds and runs on a bewildering number of platforms. Virtually
+all known and current Unix derivatives are supported (perl's native
+platform), as are other systems like VMS, DOS, OS/2, Windows,
+QNX, BeOS, OS X, MPE/iX and the Amiga.
+
+Binary distributions for some proprietary platforms can be found
+http://www.cpan.org/ports/ directory. Because these are not part of
+the standard distribution, they may and in fact do differ from the
+base perl port in a variety of ways. You'll have to check their
+respective release notes to see just what the differences are. These
+differences can be either positive (e.g. extensions for the features
+of the particular platform that are not supported in the source
+release of perl) or negative (e.g. might be based upon a less current
+source release of perl).
+
+=head2 How can I get a binary version of perl?
+
+(contributed by brian d foy)
+
+ActiveState: Windows, Linux, Mac OS X, Solaris, AIX and HP-UX
+
+ http://www.activestate.com/
+
+Sunfreeware.com: Solaris 2.5 to Solaris 10 (SPARC and x86)
+
+ http://www.sunfreeware.com/
+
+Strawberry Perl: Windows, Perl 5.8.8 and 5.10.0
+
+ http://www.strawberryperl.com
+
+IndigoPerl: Windows
+
+ http://indigostar.com/
+
+=head2 I don't have a C compiler. How can I build my own Perl interpreter?
+
+Since you don't have a C compiler, you're doomed and your vendor
+should be sacrificed to the Sun gods. But that doesn't help you.
+
+What you need to do is get a binary version of C<gcc> for your system
+first. Consult the Usenet FAQs for your operating system for
+information on where to get such a binary version.
+
+You might look around the net for a pre-built binary of Perl (or a
+C compiler!) that meets your needs, though:
+
+For Windows, Vanilla Perl ( http://vanillaperl.com/ ) and Strawberry Perl
+( http://strawberryperl.com/ ) come with a
+bundled C compiler. ActivePerl is a pre-compiled version of Perl
+ready-to-use.
+
+For Sun systems, SunFreeware.com provides binaries of most popular
+applications, including compilers and Perl.
+
+=head2 I copied the perl binary from one machine to another, but scripts don't work.
+
+That's probably because you forgot libraries, or library paths differ.
+You really should build the whole distribution on the machine it will
+eventually live on, and then type C<make install>. Most other
+approaches are doomed to failure.
+
+One simple way to check that things are in the right place is to print out
+the hard-coded C<@INC> that perl looks through for libraries:
+
+ % perl -le 'print for @INC'
+
+If this command lists any paths that don't exist on your system, then you
+may need to move the appropriate libraries to these locations, or create
+symbolic links, aliases, or shortcuts appropriately. C<@INC> is also printed as
+part of the output of
+
+ % perl -V
+
+You might also want to check out
+L<perlfaq8/"How do I keep my own module/library directory?">.
+
+=head2 I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work?
+
+Read the F<INSTALL> file, which is part of the source distribution.
+It describes in detail how to cope with most idiosyncrasies that the
+C<Configure> script can't work around for any given system or
+architecture.
+
+=head2 What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean?
+
+CPAN stands for Comprehensive Perl Archive Network, a multi-gigabyte
+archive replicated on hundreds of machines all over the world. CPAN
+contains source code, non-native ports, documentation, scripts, and
+many third-party modules and extensions, designed for everything from
+commercial database interfaces to keyboard/screen control to web
+walking and CGI scripts. The master web site for CPAN is
+http://www.cpan.org/ and there is the CPAN Multiplexer at
+http://www.cpan.org/CPAN.html which will choose a mirror near you via
+DNS. See http://www.perl.com/CPAN (without a slash at the end) for
+how this process works. Also, http://mirror.cpan.org/ has a nice
+interface to the http://www.cpan.org/MIRRORED.BY mirror directory.
+
+See the CPAN FAQ at http://www.cpan.org/misc/cpan-faq.html for answers
+to the most frequently asked questions about CPAN including how to
+become a mirror.
+
+C<CPAN/path/...> is a naming convention for files available on CPAN
+sites. CPAN indicates the base directory of a CPAN mirror, and the
+rest of the path is the path from that directory to the file. For
+instance, if you're using ftp://ftp.funet.fi/pub/languages/perl/CPAN
+as your CPAN site, the file C<CPAN/misc/japh> is downloadable as
+ftp://ftp.funet.fi/pub/languages/perl/CPAN/misc/japh .
+
+Considering that, as of 2006, there are over ten thousand existing
+modules in the archive, one probably exists to do nearly anything you
+can think of. Current categories under C<CPAN/modules/by-category/>
+include Perl core modules; development support; operating system
+interfaces; networking, devices, and interprocess communication; data
+type utilities; database interfaces; user interfaces; interfaces to
+other languages; filenames, file systems, and file locking;
+internationalization and locale; world wide web support; server and
+daemon utilities; archiving and compression; image manipulation; mail
+and news; control flow utilities; filehandle and I/O; Microsoft
+Windows modules; and miscellaneous modules.
+
+See http://www.cpan.org/modules/00modlist.long.html or
+http://search.cpan.org/ for a more complete list of modules by
+category.
+
+CPAN is a free service and is not affiliated with O'Reilly Media.
+
+=head2 Is there an ISO or ANSI certified version of Perl?
+
+Certainly not. Larry expects that he'll be certified before Perl is.
+
+=head2 Where can I get information on Perl?
+
+The complete Perl documentation is available with the Perl distribution.
+If you have Perl installed locally, you probably have the documentation
+installed as well: type C<man perl> if you're on a system resembling Unix.
+This will lead you to other important man pages, including how to set your
+C<$MANPATH>. If you're not on a Unix system, access to the documentation
+will be different; for example, documentation might only be in HTML format. All
+proper perl installations have fully-accessible documentation.
+
+You might also try C<perldoc perl> in case your system doesn't
+have a proper C<man> command, or it's been misinstalled. If that doesn't
+work, try looking in C</usr/local/lib/perl5/pod> for documentation.
+
+If all else fails, consult http://perldoc.perl.org/ which has the
+complete documentation in HTML and PDF format.
+
+Many good books have been written about Perl--see the section later in
+L<perlfaq2> for more details.
+
+Tutorial documents are included in current or upcoming Perl releases
+include L<perltoot> for objects or L<perlboot> for a beginner's
+approach to objects, L<perlopentut> for file opening semantics,
+L<perlreftut> for managing references, L<perlretut> for regular
+expressions, L<perlthrtut> for threads, L<perldebtut> for debugging,
+and L<perlxstut> for linking C and Perl together. There may be more
+by the time you read this. These URLs might also be useful:
+
+ http://perldoc.perl.org/
+ http://bookmarks.cpan.org/search.cgi?cat=Training%2FTutorials
+
+=head2 What are the Perl newsgroups on Usenet? Where do I post questions?
+
+Several groups devoted to the Perl language are on Usenet:
+
+ comp.lang.perl.announce Moderated announcement group
+ comp.lang.perl.misc High traffic general Perl discussion
+ comp.lang.perl.moderated Moderated discussion group
+ comp.lang.perl.modules Use and development of Perl modules
+ comp.lang.perl.tk Using Tk (and X) from Perl
+
+Some years ago, comp.lang.perl was divided into those groups, and
+comp.lang.perl itself officially removed. While that group may still
+be found on some news servers, it is unwise to use it, because
+postings there will not appear on news servers which honour the
+official list of group names. Use comp.lang.perl.misc for topics
+which do not have a more-appropriate specific group.
+
+There is also a Usenet gateway to Perl mailing lists sponsored by
+perl.org at nntp://nntp.perl.org , a web interface to the same lists
+at http://nntp.perl.org/group/ and these lists are also available
+under the C<perl.*> hierarchy at http://groups.google.com . Other
+groups are listed at http://lists.perl.org/ ( also known as
+http://lists.cpan.org/ ).
+
+A nice place to ask questions is the PerlMonks site,
+http://www.perlmonks.org/ , or the Perl Beginners mailing list
+http://lists.perl.org/showlist.cgi?name=beginners .
+
+Note that none of the above are supposed to write your code for you:
+asking questions about particular problems or general advice is fine,
+but asking someone to write your code for free is not very cool.
+
+=head2 Where should I post source code?
+
+You should post source code to whichever group is most appropriate, but
+feel free to cross-post to comp.lang.perl.misc. If you want to cross-post
+to alt.sources, please make sure it follows their posting standards,
+including setting the Followup-To header line to NOT include alt.sources;
+see their FAQ ( http://www.faqs.org/faqs/alt-sources-intro/ ) for details.
+
+If you're just looking for software, first use Google
+( http://www.google.com ), Google's Usenet search interface
+( http://groups.google.com ), and CPAN Search ( http://search.cpan.org ).
+This is faster and more productive than just posting a request.
+
+=head2 Perl Books
+
+A number of books on Perl and/or CGI programming are available. A few
+of these are good, some are OK, but many aren't worth your money.
+There is a list of these books, some with extensive reviews, at
+http://books.perl.org/ . If you don't see your book listed here, you
+can write to perlfaq-workers@perl.org .
+
+The incontestably definitive reference book on Perl, written by
+the creator of Perl, is Programming Perl:
+
+ Programming Perl (the "Camel Book"):
+ by Larry Wall, Tom Christiansen, and Jon Orwant
+ ISBN 0-596-00027-8 [3rd edition July 2000]
+ http://www.oreilly.com/catalog/pperl3/
+ (English, translations to several languages are also available)
+
+The companion volume to the Camel containing thousands
+of real-world examples, mini-tutorials, and complete programs is:
+
+ The Perl Cookbook (the "Ram Book"):
+ by Tom Christiansen and Nathan Torkington,
+ with Foreword by Larry Wall
+ ISBN 0-596-00313-7 [2nd Edition August 2003]
+ http://www.oreilly.com/catalog/perlckbk2/
+
+If you're already a seasoned programmer, then the Camel Book might
+suffice for you to learn Perl. If you're not, check out the
+Llama book:
+
+ Learning Perl
+ by Randal L. Schwartz, Tom Phoenix, and brian d foy
+ ISBN 0-596-10105-8 [4th edition July 2005]
+ http://www.oreilly.com/catalog/learnperl4/
+
+And for more advanced information on writing larger programs,
+presented in the same style as the Llama book, continue your education
+with the Alpaca book:
+
+ Intermediate Perl (the "Alpaca Book")
+ by Randal L. Schwartz and brian d foy, with Tom Phoenix (foreword by Damian Conway)
+ ISBN 0-596-10206-2 [1st edition March 2006]
+ http://www.oreilly.com/catalog/lrnperlorm/
+
+Addison-Wesley ( http://www.awlonline.com/ ) and Manning
+( http://www.manning.com/ ) are also publishers of some fine Perl books
+such as I<Object Oriented Programming with Perl> by Damian Conway and
+I<Network Programming with Perl> by Lincoln Stein.
+
+An excellent technical book discounter is Bookpool at
+http://www.bookpool.com/ where a 30% discount or more is not unusual.
+
+What follows is a list of the books that the FAQ authors found personally
+useful. Your mileage may (but, we hope, probably won't) vary.
+
+Recommended books on (or mostly on) Perl follow.
+
+=over 4
+
+=item References
+
+ Programming Perl
+ by Larry Wall, Tom Christiansen, and Jon Orwant
+ ISBN 0-596-00027-8 [3rd edition July 2000]
+ http://www.oreilly.com/catalog/pperl3/
+
+ Perl 5 Pocket Reference
+ by Johan Vromans
+ ISBN 0-596-00374-9 [4th edition July 2002]
+ http://www.oreilly.com/catalog/perlpr4/
+
+=item Tutorials
+
+ Beginning Perl
+ by James Lee
+ ISBN 1-59059-391-X [2nd edition August 2004]
+ http://apress.com/book/bookDisplay.html?bID=344
+
+ Elements of Programming with Perl
+ by Andrew L. Johnson
+ ISBN 1-884777-80-5 [1st edition October 1999]
+ http://www.manning.com/johnson/
+
+ Learning Perl
+ by Randal L. Schwartz, Tom Phoenix, and brian d foy
+ ISBN 0-596-52010-7 [5th edition June 2008]
+ http://oreilly.com/catalog/9780596520106/
+
+ Intermediate Perl (the "Alpaca Book")
+ by Randal L. Schwartz and brian d foy, with Tom Phoenix (foreword by Damian Conway)
+ ISBN 0-596-10206-2 [1st edition March 2006]
+ http://www.oreilly.com/catalog/intermediateperl/
+
+ Mastering Perl
+ by brian d foy
+ ISBN 0-596-52724-1 [1st edition July 2007]
+ http://www.oreilly.com/catalog/9780596527242/
+
+=item Task-Oriented
+
+ Writing Perl Modules for CPAN
+ by Sam Tregar
+ ISBN 1-59059-018-X [1st edition August 2002]
+ http://apress.com/book/bookDisplay.html?bID=14
+
+ The Perl Cookbook
+ by Tom Christiansen and Nathan Torkington
+ with foreword by Larry Wall
+ ISBN 1-56592-243-3 [1st edition August 1998]
+ http://www.oreilly.com/catalog/cookbook/
+
+ Effective Perl Programming
+ by Joseph Hall
+ ISBN 0-201-41975-0 [1st edition 1998]
+ http://www.awl.com/
+
+ Real World SQL Server Administration with Perl
+ by Linchi Shea
+ ISBN 1-59059-097-X [1st edition July 2003]
+ http://apress.com/book/bookDisplay.html?bID=171
+
+=item Special Topics
+
+ Perl Best Practices
+ by Damian Conway
+ ISBN: 0-596-00173-8 [1st edition July 2005]
+ http://www.oreilly.com/catalog/perlbp/
+
+ Higher Order Perl
+ by Mark-Jason Dominus
+ ISBN: 1558607013 [1st edition March 2005]
+ http://hop.perl.plover.com/
+
+ Perl 6 Now: The Core Ideas Illustrated with Perl 5
+ by Scott Walters
+ ISBN 1-59059-395-2 [1st edition December 2004]
+ http://apress.com/book/bookDisplay.html?bID=355
+
+ Mastering Regular Expressions
+ by Jeffrey E. F. Friedl
+ ISBN 0-596-00289-0 [2nd edition July 2002]
+ http://www.oreilly.com/catalog/regex2/
+
+ Network Programming with Perl
+ by Lincoln Stein
+ ISBN 0-201-61571-1 [1st edition 2001]
+ http://www.awlonline.com/
+
+ Object Oriented Perl
+ by Damian Conway
+ with foreword by Randal L. Schwartz
+ ISBN 1-884777-79-1 [1st edition August 1999]
+ http://www.manning.com/conway/
+
+ Data Munging with Perl
+ by Dave Cross
+ ISBN 1-930110-00-6 [1st edition 2001]
+ http://www.manning.com/cross
+
+ Mastering Perl/Tk
+ by Steve Lidie and Nancy Walsh
+ ISBN 1-56592-716-8 [1st edition January 2002]
+ http://www.oreilly.com/catalog/mastperltk/
+
+ Extending and Embedding Perl
+ by Tim Jenness and Simon Cozens
+ ISBN 1-930110-82-0 [1st edition August 2002]
+ http://www.manning.com/jenness
+
+ Perl Debugger Pocket Reference
+ by Richard Foley
+ ISBN 0-596-00503-2 [1st edition January 2004]
+ http://www.oreilly.com/catalog/perldebugpr/
+
+ Pro Perl Debugging
+ by Richard Foley with Andy Lester
+ ISBN 1-59059-454-1 [1st edition July 2005]
+ http://www.apress.com/book/view/1590594541
+
+=back
+
+=head2 Which magazines have Perl content?
+
+I<The Perl Review> ( http://www.theperlreview.com ) focuses on Perl
+almost completely (although it sometimes sneaks in an article about
+another language). There's also I<$foo Magazin>, a german magazine
+dedicated to Perl, at ( http://www.foo-magazin.de ).
+
+The I<Perl-Zeitung> is a German-speaking magazine for Perl beginners
+(see http://perl-zeitung.at.tf ).
+
+Magazines that frequently carry quality articles on Perl include I<The
+Perl Review> ( http://www.theperlreview.com ), I<Unix Review> (
+http://www.unixreview.com/ ), I<Linux Magazine> (
+http://www.linuxmagazine.com/ ), and Usenix's newsletter/magazine to
+its members, I<login:> ( http://www.usenix.org/ ).
+
+The Perl columns of Randal L. Schwartz are available on the web at
+http://www.stonehenge.com/merlyn/WebTechniques/ ,
+http://www.stonehenge.com/merlyn/UnixReview/ , and
+http://www.stonehenge.com/merlyn/LinuxMag/ .
+
+The first (and for a long time, only) periodical devoted to All Things
+Perl, I<The Perl Journal> contains tutorials, demonstrations, case
+studies, announcements, contests, and much more. I<TPJ> has columns
+on web development, databases, Win32 Perl, graphical programming,
+regular expressions, and networking, and sponsors the Obfuscated Perl
+Contest and the Perl Poetry Contests. Beginning in November 2002, I<TPJ>
+moved to a reader-supported monthly e-zine format in which subscribers
+can download issues as PDF documents. In 2006, I<TPJ> merged with Dr.
+Dobbs Journal (online edition). To read old I<TPJ> articles, see
+http://www.ddj.com/ .
+
+=head2 What mailing lists are there for Perl?
+
+Most of the major modules (C<Tk>, C<CGI>, C<libwww-perl>) have their own
+mailing lists. Consult the documentation that came with the module for
+subscription information.
+
+A comprehensive list of Perl related mailing lists can be found at:
+
+ http://lists.perl.org/
+
+=head2 Where are the archives for comp.lang.perl.misc?
+
+The Google search engine now carries archived and searchable newsgroup
+content.
+
+http://groups.google.com/group/comp.lang.perl.misc/topics
+
+If you have a question, you can be sure someone has already asked the
+same question at some point on c.l.p.m. It requires some time and patience
+to sift through all the content but often you will find the answer you
+seek.
+
+=head2 Where can I buy a commercial version of perl?
+
+In a real sense, perl already I<is> commercial software: it has a license
+that you can grab and carefully read to your manager. It is distributed
+in releases and comes in well-defined packages. There is a very large
+user community and an extensive literature. The comp.lang.perl.*
+newsgroups and several of the mailing lists provide free answers to your
+questions in near real-time. Perl has traditionally been supported by
+Larry, scores of software designers and developers, and myriad
+programmers, all working for free to create a useful thing to make life
+better for everyone.
+
+However, these answers may not suffice for managers who require a
+purchase order from a company whom they can sue should anything go awry.
+Or maybe they need very serious hand-holding and contractual obligations.
+Shrink-wrapped CDs with perl on them are available from several sources if
+that will help. For example, many Perl books include a distribution of perl,
+as do the O'Reilly Perl Resource Kits (in both the Unix flavor
+and in the proprietary Microsoft flavor); the free Unix distributions
+also all come with perl.
+
+=head2 Where do I send bug reports?
+
+(contributed by brian d foy)
+
+First, ensure that you've found an actual bug. Second, ensure you've
+found an actual bug.
+
+If you've found a bug with the perl interpreter or one of the modules
+in the standard library (those that come with Perl), you can use the
+C<perlbug> utility that comes with Perl (>= 5.004). It collects
+information about your installation to include with your message, then
+sends the message to the right place.
+
+To determine if a module came with your version of Perl, you can
+use the C<Module::CoreList> module. It has the information about
+the modules (with their versions) included with each release of Perl.
+
+If C<Module::CoreList> is not installed on your system, check out
+http://perlpunks.de/corelist .
+
+Every CPAN module has a bug tracker set up in RT, http://rt.cpan.org .
+You can submit bugs to RT either through its web interface or by
+email. To email a bug report, send it to
+bug-E<lt>distribution-nameE<gt>@rt.cpan.org . For example, if you
+wanted to report a bug in C<Business::ISBN>, you could send a message to
+bug-Business-ISBN@rt.cpan.org .
+
+Some modules might have special reporting requirements, such as a
+Sourceforge or Google Code tracking system, so you should check the
+module documentation too.
+
+=head2 What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org?
+
+Perl.com at http://www.perl.com/ is part of the O'Reilly Network, a
+subsidiary of O'Reilly Media.
+
+The Perl Foundation is an advocacy organization for the Perl language
+which maintains the web site http://www.perl.org/ as a general
+advocacy site for the Perl language. It uses the domain to provide
+general support services to the Perl community, including the hosting
+of mailing lists, web sites, and other services. There are also many
+other sub-domains for special topics like learning Perl, Perl news, jobs
+in Perl, such as:
+
+ http://learn.perl.org/
+ http://use.perl.org/
+ http://jobs.perl.org/
+ http://lists.perl.org/
+
+Perl Mongers uses the pm.org domain for services related to Perl user
+groups, including the hosting of mailing lists and web sites. See the
+Perl user group web site at http://www.pm.org/ for more information about
+joining, starting, or requesting services for a Perl user group.
+
+http://www.cpan.org/ is the Comprehensive Perl Archive Network,
+a replicated worldwide repository of Perl software, see
+the I<What is CPAN?> question earlier in this document.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples here are in the public
+domain. You are permitted and encouraged to use this code and any
+derivatives thereof in your own programs for fun or for profit as you
+see fit. A simple comment in the code giving credit to the FAQ would
+be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq3.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq3.pod
new file mode 100644
index 00000000000..e2fe11621ba
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq3.pod
@@ -0,0 +1,1097 @@
+=head1 NAME
+
+perlfaq3 - Programming Tools
+
+=head1 DESCRIPTION
+
+This section of the FAQ answers questions related to programmer tools
+and programming support.
+
+=head2 How do I do (anything)?
+
+Have you looked at CPAN (see L<perlfaq2>)? The chances are that
+someone has already written a module that can solve your problem.
+Have you read the appropriate manpages? Here's a brief index:
+
+ Basics perldata, perlvar, perlsyn, perlop, perlsub
+ Execution perlrun, perldebug
+ Functions perlfunc
+ Objects perlref, perlmod, perlobj, perltie
+ Data Structures perlref, perllol, perldsc
+ Modules perlmod, perlmodlib, perlsub
+ Regexes perlre, perlfunc, perlop, perllocale
+ Moving to perl5 perltrap, perl
+ Linking w/C perlxstut, perlxs, perlcall, perlguts, perlembed
+ Various http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz
+ (not a man-page but still useful, a collection
+ of various essays on Perl techniques)
+
+A crude table of contents for the Perl manpage set is found in L<perltoc>.
+
+=head2 How can I use Perl interactively?
+
+The typical approach uses the Perl debugger, described in the
+C<perldebug(1)> manpage, on an "empty" program, like this:
+
+ perl -de 42
+
+Now just type in any legal Perl code, and it will be immediately
+evaluated. You can also examine the symbol table, get stack
+backtraces, check variable values, set breakpoints, and other
+operations typically found in symbolic debuggers.
+
+=head2 Is there a Perl shell?
+
+The C<psh> (Perl sh) is currently at version 1.8. The Perl Shell is a shell
+that combines the interactive nature of a Unix shell with the power of
+Perl. The goal is a full featured shell that behaves as expected for
+normal shell activity and uses Perl syntax and functionality for
+control-flow statements and other things. You can get C<psh> at
+http://sourceforge.net/projects/psh/ .
+
+C<Zoidberg> is a similar project and provides a shell written in perl,
+configured in perl and operated in perl. It is intended as a login shell
+and development environment. It can be found at
+http://pardus-larus.student.utwente.nl/~pardus/projects/zoidberg/
+or your local CPAN mirror.
+
+The C<Shell.pm> module (distributed with Perl) makes Perl try commands
+which aren't part of the Perl language as shell commands. C<perlsh> from
+the source distribution is simplistic and uninteresting, but may still
+be what you want.
+
+=head2 How do I find which modules are installed on my system?
+
+From the command line, you can use the C<cpan> command's C<-l> switch:
+
+ $ cpan -l
+
+You can also use C<cpan>'s C<-a> switch to create an autobundle file
+that C<CPAN.pm> understands and can use to re-install every module:
+
+ $ cpan -a
+
+Inside a Perl program, you can use the C<ExtUtils::Installed> module to
+show all installed distributions, although it can take awhile to do
+its magic. The standard library which comes with Perl just shows up
+as "Perl" (although you can get those with C<Module::CoreList>).
+
+ use ExtUtils::Installed;
+
+ my $inst = ExtUtils::Installed->new();
+ my @modules = $inst->modules();
+
+If you want a list of all of the Perl module filenames, you
+can use C<File::Find::Rule>:
+
+ use File::Find::Rule;
+
+ my @files = File::Find::Rule->
+ extras({follow => 1})->
+ file()->
+ name( '*.pm' )->
+ in( @INC )
+ ;
+
+If you do not have that module, you can do the same thing
+with C<File::Find> which is part of the standard library:
+
+ use File::Find;
+ my @files;
+
+ find(
+ {
+ wanted => sub {
+ push @files, $File::Find::fullname
+ if -f $File::Find::fullname && /\.pm$/
+ },
+ follow => 1,
+ follow_skip => 2,
+ },
+ @INC
+ );
+
+ print join "\n", @files;
+
+If you simply need to quickly check to see if a module is
+available, you can check for its documentation. If you can
+read the documentation the module is most likely installed.
+If you cannot read the documentation, the module might not
+have any (in rare cases):
+
+ $ perldoc Module::Name
+
+You can also try to include the module in a one-liner to see if
+perl finds it:
+
+ $ perl -MModule::Name -e1
+
+=head2 How do I debug my Perl programs?
+
+(contributed by brian d foy)
+
+Before you do anything else, you can help yourself by ensuring that
+you let Perl tell you about problem areas in your code. By turning
+on warnings and strictures, you can head off many problems before
+they get too big. You can find out more about these in L<strict>
+and L<warnings>.
+
+ #!/usr/bin/perl
+ use strict;
+ use warnings;
+
+Beyond that, the simplest debugger is the C<print> function. Use it
+to look at values as you run your program:
+
+ print STDERR "The value is [$value]\n";
+
+The C<Data::Dumper> module can pretty-print Perl data structures:
+
+ use Data::Dumper qw( Dumper );
+ print STDERR "The hash is " . Dumper( \%hash ) . "\n";
+
+Perl comes with an interactive debugger, which you can start with the
+C<-d> switch. It's fully explained in L<perldebug>.
+
+If you'd like a graphical user interface and you have C<Tk>, you can use
+C<ptkdb>. It's on CPAN and available for free.
+
+If you need something much more sophisticated and controllable, Leon
+Brocard's C<Devel::ebug> (which you can call with the C<-D> switch as C<-Debug>)
+gives you the programmatic hooks into everything you need to write your
+own (without too much pain and suffering).
+
+You can also use a commercial debugger such as Affrus (Mac OS X), Komodo
+from Activestate (Windows and Mac OS X), or EPIC (most platforms).
+
+=head2 How do I profile my Perl programs?
+
+(contributed by brian d foy, updated Fri Jul 25 12:22:26 PDT 2008)
+
+The C<Devel> namespace has several modules which you can use to
+profile your Perl programs. The C<Devel::DProf> module comes with Perl
+and you can invoke it with the C<-d> switch:
+
+ perl -d:DProf program.pl
+
+After running your program under C<DProf>, you'll get a F<tmon.out> file
+with the profile data. To look at the data, you can turn it into a
+human-readable report with the C<dprofpp> program that comes with
+C<Devel::DProf>.
+
+ dprofpp
+
+You can also do the profiling and reporting in one step with the C<-p>
+switch to C<dprofpp>:
+
+ dprofpp -p program.pl
+
+The C<Devel::NYTProf> (New York Times Profiler) does both statement
+and subroutine profiling. It's available from CPAN and you also invoke
+it with the C<-d> switch:
+
+ perl -d:NYTProf some_perl.pl
+
+Like C<DProf>, it creates a database of the profile information that you
+can turn into reports. The C<nytprofhtml> command turns the data into
+an HTML report similar to the C<Devel::Cover> report:
+
+ nytprofhtml
+
+CPAN has several other profilers that you can invoke in the same
+fashion. You might also be interested in using the C<Benchmark> to
+measure and compare code snippets.
+
+You can read more about profiling in I<Programming Perl>, chapter 20,
+or I<Mastering Perl>, chapter 5.
+
+L<perldebguts> documents creating a custom debugger if you need to
+create a special sort of profiler. brian d foy describes the process
+in I<The Perl Journal>, "Creating a Perl Debugger",
+http://www.ddj.com/184404522 , and "Profiling in Perl"
+http://www.ddj.com/184404580 .
+
+Perl.com has two interesting articles on profiling: "Profiling Perl",
+by Simon Cozens, http://www.perl.com/lpt/a/850 and "Debugging and
+Profiling mod_perl Applications", by Frank Wiles,
+http://www.perl.com/pub/a/2006/02/09/debug_mod_perl.html .
+
+Randal L. Schwartz writes about profiling in "Speeding up Your Perl
+Programs" for I<Unix Review>,
+http://www.stonehenge.com/merlyn/UnixReview/col49.html , and "Profiling
+in Template Toolkit via Overriding" for I<Linux Magazine>,
+http://www.stonehenge.com/merlyn/LinuxMag/col75.html .
+
+=head2 How do I cross-reference my Perl programs?
+
+The C<B::Xref> module can be used to generate cross-reference reports
+for Perl programs.
+
+ perl -MO=Xref[,OPTIONS] scriptname.plx
+
+=head2 Is there a pretty-printer (formatter) for Perl?
+
+C<Perltidy> is a Perl script which indents and reformats Perl scripts
+to make them easier to read by trying to follow the rules of the
+L<perlstyle>. If you write Perl scripts, or spend much time reading
+them, you will probably find it useful. It is available at
+http://perltidy.sourceforge.net .
+
+Of course, if you simply follow the guidelines in L<perlstyle>,
+you shouldn't need to reformat. The habit of formatting your code
+as you write it will help prevent bugs. Your editor can and should
+help you with this. The perl-mode or newer cperl-mode for emacs
+can provide remarkable amounts of help with most (but not all)
+code, and even less programmable editors can provide significant
+assistance. Tom Christiansen and many other VI users swear by
+the following settings in vi and its clones:
+
+ set ai sw=4
+ map! ^O {^M}^[O^T
+
+Put that in your F<.exrc> file (replacing the caret characters
+with control characters) and away you go. In insert mode, ^T is
+for indenting, ^D is for undenting, and ^O is for blockdenting--as
+it were. A more complete example, with comments, can be found at
+http://www.cpan.org/authors/id/TOMC/scripts/toms.exrc.gz
+
+The a2ps http://www-inf.enst.fr/%7Edemaille/a2ps/black+white.ps.gz does
+lots of things related to generating nicely printed output of
+documents.
+
+=head2 Is there a ctags for Perl?
+
+(contributed by brian d foy)
+
+Ctags uses an index to quickly find things in source code, and many
+popular editors support ctags for several different languages,
+including Perl.
+
+Exuberent ctags supports Perl: http://ctags.sourceforge.net/
+
+You might also try pltags: http://www.mscha.com/pltags.zip
+
+=head2 Is there an IDE or Windows Perl Editor?
+
+Perl programs are just plain text, so any editor will do.
+
+If you're on Unix, you already have an IDE--Unix itself. The Unix
+philosophy is the philosophy of several small tools that each do one
+thing and do it well. It's like a carpenter's toolbox.
+
+If you want an IDE, check the following (in alphabetical order, not
+order of preference):
+
+=over 4
+
+=item Eclipse
+
+http://e-p-i-c.sf.net/
+
+The Eclipse Perl Integration Project integrates Perl
+editing/debugging with Eclipse.
+
+=item Enginsite
+
+http://www.enginsite.com/
+
+Perl Editor by EngInSite is a complete integrated development
+environment (IDE) for creating, testing, and debugging Perl scripts;
+the tool runs on Windows 9x/NT/2000/XP or later.
+
+=item Komodo
+
+http://www.ActiveState.com/Products/Komodo/
+
+ActiveState's cross-platform (as of October 2004, that's Windows, Linux,
+and Solaris), multi-language IDE has Perl support, including a regular expression
+debugger and remote debugging.
+
+=item Notepad++
+
+http://notepad-plus.sourceforge.net/
+
+=item Open Perl IDE
+
+http://open-perl-ide.sourceforge.net/
+
+Open Perl IDE is an integrated development environment for writing
+and debugging Perl scripts with ActiveState's ActivePerl distribution
+under Windows 95/98/NT/2000.
+
+=item OptiPerl
+
+http://www.optiperl.com/
+
+OptiPerl is a Windows IDE with simulated CGI environment, including
+debugger and syntax highlighting editor.
+
+=item Padre
+
+http://padre.perlide.org/
+
+Padre is cross-platform IDE for Perl written in Perl using wxWidgets to provide
+a native look and feel. It's open source under the Artistic License.
+
+=item PerlBuilder
+
+http://www.solutionsoft.com/perl.htm
+
+PerlBuilder is an integrated development environment for Windows that
+supports Perl development.
+
+=item visiPerl+
+
+http://helpconsulting.net/visiperl/
+
+From Help Consulting, for Windows.
+
+=item Visual Perl
+
+http://www.activestate.com/Products/Visual_Perl/
+
+Visual Perl is a Visual Studio.NET plug-in from ActiveState.
+
+=item Zeus
+
+http://www.zeusedit.com/lookmain.html
+
+Zeus for Window is another Win32 multi-language editor/IDE
+that comes with support for Perl:
+
+=back
+
+For editors: if you're on Unix you probably have vi or a vi clone
+already, and possibly an emacs too, so you may not need to download
+anything. In any emacs the cperl-mode (M-x cperl-mode) gives you
+perhaps the best available Perl editing mode in any editor.
+
+If you are using Windows, you can use any editor that lets you work
+with plain text, such as NotePad or WordPad. Word processors, such as
+Microsoft Word or WordPerfect, typically do not work since they insert
+all sorts of behind-the-scenes information, although some allow you to
+save files as "Text Only". You can also download text editors designed
+specifically for programming, such as Textpad (
+http://www.textpad.com/ ) and UltraEdit ( http://www.ultraedit.com/ ),
+among others.
+
+If you are using MacOS, the same concerns apply. MacPerl (for Classic
+environments) comes with a simple editor. Popular external editors are
+BBEdit ( http://www.bbedit.com/ ) or Alpha (
+http://www.his.com/~jguyer/Alpha/Alpha8.html ). MacOS X users can use
+Unix editors as well.
+
+=over 4
+
+=item GNU Emacs
+
+http://www.gnu.org/software/emacs/windows/ntemacs.html
+
+=item MicroEMACS
+
+http://www.microemacs.de/
+
+=item XEmacs
+
+http://www.xemacs.org/Download/index.html
+
+=item Jed
+
+http://space.mit.edu/~davis/jed/
+
+=back
+
+or a vi clone such as
+
+=over 4
+
+=item Elvis
+
+ftp://ftp.cs.pdx.edu/pub/elvis/ http://www.fh-wedel.de/elvis/
+
+=item Vile
+
+http://dickey.his.com/vile/vile.html
+
+=item Vim
+
+http://www.vim.org/
+
+=back
+
+For vi lovers in general, Windows or elsewhere:
+
+ http://www.thomer.com/thomer/vi/vi.html
+
+nvi ( http://www.bostic.com/vi/ , available from CPAN in src/misc/) is
+yet another vi clone, unfortunately not available for Windows, but in
+Unix platforms you might be interested in trying it out, firstly because
+strictly speaking it is not a vi clone, it is the real vi, or the new
+incarnation of it, and secondly because you can embed Perl inside it
+to use Perl as the scripting language. nvi is not alone in this,
+though: at least also vim and vile offer an embedded Perl.
+
+The following are Win32 multilanguage editor/IDEs that support Perl:
+
+=over 4
+
+=item Codewright
+
+http://www.borland.com/codewright/
+
+=item MultiEdit
+
+http://www.MultiEdit.com/
+
+=item SlickEdit
+
+http://www.slickedit.com/
+
+=item ConTEXT
+
+http://www.contexteditor.org/
+
+=back
+
+There is also a toyedit Text widget based editor written in Perl
+that is distributed with the Tk module on CPAN. The ptkdb
+( http://ptkdb.sourceforge.net/ ) is a Perl/tk based debugger that
+acts as a development environment of sorts. Perl Composer
+( http://perlcomposer.sourceforge.net/ ) is an IDE for Perl/Tk
+GUI creation.
+
+In addition to an editor/IDE you might be interested in a more
+powerful shell environment for Win32. Your options include
+
+=over 4
+
+=item Bash
+
+from the Cygwin package ( http://sources.redhat.com/cygwin/ )
+
+=item Ksh
+
+from the MKS Toolkit ( http://www.mkssoftware.com/ ), or the Bourne shell of
+the U/WIN environment ( http://www.research.att.com/sw/tools/uwin/ )
+
+=item Tcsh
+
+ftp://ftp.astron.com/pub/tcsh/ , see also
+http://www.primate.wisc.edu/software/csh-tcsh-book/
+
+=item Zsh
+
+http://www.zsh.org/
+
+=back
+
+MKS and U/WIN are commercial (U/WIN is free for educational and
+research purposes), Cygwin is covered by the GNU General Public
+License (but that shouldn't matter for Perl use). The Cygwin, MKS,
+and U/WIN all contain (in addition to the shells) a comprehensive set
+of standard Unix toolkit utilities.
+
+If you're transferring text files between Unix and Windows using FTP
+be sure to transfer them in ASCII mode so the ends of lines are
+appropriately converted.
+
+On Mac OS the MacPerl Application comes with a simple 32k text editor
+that behaves like a rudimentary IDE. In contrast to the MacPerl Application
+the MPW Perl tool can make use of the MPW Shell itself as an editor (with
+no 32k limit).
+
+=over 4
+
+=item Affrus
+
+is a full Perl development environment with full debugger support
+( http://www.latenightsw.com ).
+
+=item Alpha
+
+is an editor, written and extensible in Tcl, that nonetheless has
+built in support for several popular markup and programming languages
+including Perl and HTML ( http://www.his.com/~jguyer/Alpha/Alpha8.html ).
+
+=item BBEdit and BBEdit Lite
+
+are text editors for Mac OS that have a Perl sensitivity mode
+( http://web.barebones.com/ ).
+
+=back
+
+=head2 Where can I get Perl macros for vi?
+
+For a complete version of Tom Christiansen's vi configuration file,
+see http://www.cpan.org/authors/Tom_Christiansen/scripts/toms.exrc.gz ,
+the standard benchmark file for vi emulators. The file runs best with nvi,
+the current version of vi out of Berkeley, which incidentally can be built
+with an embedded Perl interpreter--see http://www.cpan.org/src/misc/ .
+
+=head2 Where can I get perl-mode or cperl-mode for emacs?
+X<emacs>
+
+Since Emacs version 19 patchlevel 22 or so, there have been both a
+perl-mode.el and support for the Perl debugger built in. These should
+come with the standard Emacs 19 distribution.
+
+Note that the perl-mode of emacs will have fits with C<"main'foo">
+(single quote), and mess up the indentation and highlighting. You
+are probably using C<"main::foo"> in new Perl code anyway, so this
+shouldn't be an issue.
+
+For CPerlMode, see http://www.emacswiki.org/cgi-bin/wiki/CPerlMode
+
+=head2 How can I use curses with Perl?
+
+The Curses module from CPAN provides a dynamically loadable object
+module interface to a curses library. A small demo can be found at the
+directory http://www.cpan.org/authors/Tom_Christiansen/scripts/rep.gz ;
+this program repeats a command and updates the screen as needed, rendering
+B<rep ps axu> similar to B<top>.
+
+=head2 How can I write a GUI (X, Tk, Gtk, etc.) in Perl?
+X<GUI> X<Tk> X<Wx> X<WxWidgets> X<Gtk> X<Gtk2> X<CamelBones> X<Qt>
+
+(contributed by Ben Morrow)
+
+There are a number of modules which let you write GUIs in Perl. Most
+GUI toolkits have a perl interface: an incomplete list follows.
+
+=over 4
+
+=item Tk
+
+This works under Unix and Windows, and the current version doesn't
+look half as bad under Windows as it used to. Some of the gui elements
+still don't 'feel' quite right, though. The interface is very natural
+and 'perlish', making it easy to use in small scripts that just need a
+simple gui. It hasn't been updated in a while.
+
+=item Wx
+
+This is a Perl binding for the cross-platform wxWidgets toolkit
+( http://www.wxwidgets.org ). It works under Unix, Win32 and Mac OS X,
+using native widgets (Gtk under Unix). The interface follows the C++
+interface closely, but the documentation is a little sparse for someone
+who doesn't know the library, mostly just referring you to the C++
+documentation.
+
+=item Gtk and Gtk2
+
+These are Perl bindings for the Gtk toolkit ( http://www.gtk.org ). The
+interface changed significantly between versions 1 and 2 so they have
+separate Perl modules. It runs under Unix, Win32 and Mac OS X (currently
+it requires an X server on Mac OS, but a 'native' port is underway), and
+the widgets look the same on every plaform: i.e., they don't match the
+native widgets. As with Wx, the Perl bindings follow the C API closely,
+and the documentation requires you to read the C documentation to
+understand it.
+
+=item Win32::GUI
+
+This provides access to most of the Win32 GUI widgets from Perl.
+Obviously, it only runs under Win32, and uses native widgets. The Perl
+interface doesn't really follow the C interface: it's been made more
+Perlish, and the documentation is pretty good. More advanced stuff may
+require familiarity with the C Win32 APIs, or reference to MSDN.
+
+=item CamelBones
+
+CamelBones ( http://camelbones.sourceforge.net ) is a Perl interface to
+Mac OS X's Cocoa GUI toolkit, and as such can be used to produce native
+GUIs on Mac OS X. It's not on CPAN, as it requires frameworks that
+CPAN.pm doesn't know how to install, but installation is via the
+standard OSX package installer. The Perl API is, again, very close to
+the ObjC API it's wrapping, and the documentation just tells you how to
+translate from one to the other.
+
+=item Qt
+
+There is a Perl interface to TrollTech's Qt toolkit, but it does not
+appear to be maintained.
+
+=item Athena
+
+Sx is an interface to the Athena widget set which comes with X, but
+again it appears not to be much used nowadays.
+
+=back
+
+=head2 How can I make my Perl program run faster?
+
+The best way to do this is to come up with a better algorithm. This
+can often make a dramatic difference. Jon Bentley's book
+I<Programming Pearls> (that's not a misspelling!) has some good tips
+on optimization, too. Advice on benchmarking boils down to: benchmark
+and profile to make sure you're optimizing the right part, look for
+better algorithms instead of microtuning your code, and when all else
+fails consider just buying faster hardware. You will probably want to
+read the answer to the earlier question "How do I profile my Perl
+programs?" if you haven't done so already.
+
+A different approach is to autoload seldom-used Perl code. See the
+AutoSplit and AutoLoader modules in the standard distribution for
+that. Or you could locate the bottleneck and think about writing just
+that part in C, the way we used to take bottlenecks in C code and
+write them in assembler. Similar to rewriting in C, modules that have
+critical sections can be written in C (for instance, the PDL module
+from CPAN).
+
+If you're currently linking your perl executable to a shared
+I<libc.so>, you can often gain a 10-25% performance benefit by
+rebuilding it to link with a static libc.a instead. This will make a
+bigger perl executable, but your Perl programs (and programmers) may
+thank you for it. See the F<INSTALL> file in the source distribution
+for more information.
+
+The undump program was an ancient attempt to speed up Perl program by
+storing the already-compiled form to disk. This is no longer a viable
+option, as it only worked on a few architectures, and wasn't a good
+solution anyway.
+
+=head2 How can I make my Perl program take less memory?
+
+When it comes to time-space tradeoffs, Perl nearly always prefers to
+throw memory at a problem. Scalars in Perl use more memory than
+strings in C, arrays take more than that, and hashes use even more. While
+there's still a lot to be done, recent releases have been addressing
+these issues. For example, as of 5.004, duplicate hash keys are
+shared amongst all hashes using them, so require no reallocation.
+
+In some cases, using substr() or vec() to simulate arrays can be
+highly beneficial. For example, an array of a thousand booleans will
+take at least 20,000 bytes of space, but it can be turned into one
+125-byte bit vector--a considerable memory savings. The standard
+Tie::SubstrHash module can also help for certain types of data
+structure. If you're working with specialist data structures
+(matrices, for instance) modules that implement these in C may use
+less memory than equivalent Perl modules.
+
+Another thing to try is learning whether your Perl was compiled with
+the system malloc or with Perl's builtin malloc. Whichever one it
+is, try using the other one and see whether this makes a difference.
+Information about malloc is in the F<INSTALL> file in the source
+distribution. You can find out whether you are using perl's malloc by
+typing C<perl -V:usemymalloc>.
+
+Of course, the best way to save memory is to not do anything to waste
+it in the first place. Good programming practices can go a long way
+toward this:
+
+=over 4
+
+=item * Don't slurp!
+
+Don't read an entire file into memory if you can process it line
+by line. Or more concretely, use a loop like this:
+
+ #
+ # Good Idea
+ #
+ while (<FILE>) {
+ # ...
+ }
+
+instead of this:
+
+ #
+ # Bad Idea
+ #
+ @data = <FILE>;
+ foreach (@data) {
+ # ...
+ }
+
+When the files you're processing are small, it doesn't much matter which
+way you do it, but it makes a huge difference when they start getting
+larger.
+
+=item * Use map and grep selectively
+
+Remember that both map and grep expect a LIST argument, so doing this:
+
+ @wanted = grep {/pattern/} <FILE>;
+
+will cause the entire file to be slurped. For large files, it's better
+to loop:
+
+ while (<FILE>) {
+ push(@wanted, $_) if /pattern/;
+ }
+
+=item * Avoid unnecessary quotes and stringification
+
+Don't quote large strings unless absolutely necessary:
+
+ my $copy = "$large_string";
+
+makes 2 copies of $large_string (one for $copy and another for the
+quotes), whereas
+
+ my $copy = $large_string;
+
+only makes one copy.
+
+Ditto for stringifying large arrays:
+
+ {
+ local $, = "\n";
+ print @big_array;
+ }
+
+is much more memory-efficient than either
+
+ print join "\n", @big_array;
+
+or
+
+ {
+ local $" = "\n";
+ print "@big_array";
+ }
+
+
+=item * Pass by reference
+
+Pass arrays and hashes by reference, not by value. For one thing, it's
+the only way to pass multiple lists or hashes (or both) in a single
+call/return. It also avoids creating a copy of all the contents. This
+requires some judgement, however, because any changes will be propagated
+back to the original data. If you really want to mangle (er, modify) a
+copy, you'll have to sacrifice the memory needed to make one.
+
+=item * Tie large variables to disk.
+
+For "big" data stores (i.e. ones that exceed available memory) consider
+using one of the DB modules to store it on disk instead of in RAM. This
+will incur a penalty in access time, but that's probably better than
+causing your hard disk to thrash due to massive swapping.
+
+=back
+
+=head2 Is it safe to return a reference to local or lexical data?
+
+Yes. Perl's garbage collection system takes care of this so
+everything works out right.
+
+ sub makeone {
+ my @a = ( 1 .. 10 );
+ return \@a;
+ }
+
+ for ( 1 .. 10 ) {
+ push @many, makeone();
+ }
+
+ print $many[4][5], "\n";
+
+ print "@many\n";
+
+=head2 How can I free an array or hash so my program shrinks?
+
+(contributed by Michael Carman)
+
+You usually can't. Memory allocated to lexicals (i.e. my() variables)
+cannot be reclaimed or reused even if they go out of scope. It is
+reserved in case the variables come back into scope. Memory allocated
+to global variables can be reused (within your program) by using
+undef() and/or delete().
+
+On most operating systems, memory allocated to a program can never be
+returned to the system. That's why long-running programs sometimes re-
+exec themselves. Some operating systems (notably, systems that use
+mmap(2) for allocating large chunks of memory) can reclaim memory that
+is no longer used, but on such systems, perl must be configured and
+compiled to use the OS's malloc, not perl's.
+
+In general, memory allocation and de-allocation isn't something you can
+or should be worrying about much in Perl.
+
+See also "How can I make my Perl program take less memory?"
+
+=head2 How can I make my CGI script more efficient?
+
+Beyond the normal measures described to make general Perl programs
+faster or smaller, a CGI program has additional issues. It may be run
+several times per second. Given that each time it runs it will need
+to be re-compiled and will often allocate a megabyte or more of system
+memory, this can be a killer. Compiling into C B<isn't going to help
+you> because the process start-up overhead is where the bottleneck is.
+
+There are two popular ways to avoid this overhead. One solution
+involves running the Apache HTTP server (available from
+http://www.apache.org/ ) with either of the mod_perl or mod_fastcgi
+plugin modules.
+
+With mod_perl and the Apache::Registry module (distributed with
+mod_perl), httpd will run with an embedded Perl interpreter which
+pre-compiles your script and then executes it within the same address
+space without forking. The Apache extension also gives Perl access to
+the internal server API, so modules written in Perl can do just about
+anything a module written in C can. For more on mod_perl, see
+http://perl.apache.org/
+
+With the FCGI module (from CPAN) and the mod_fastcgi
+module (available from http://www.fastcgi.com/ ) each of your Perl
+programs becomes a permanent CGI daemon process.
+
+Both of these solutions can have far-reaching effects on your system
+and on the way you write your CGI programs, so investigate them with
+care.
+
+See http://www.cpan.org/modules/by-category/15_World_Wide_Web_HTML_HTTP_CGI/ .
+
+=head2 How can I hide the source for my Perl program?
+
+Delete it. :-) Seriously, there are a number of (mostly
+unsatisfactory) solutions with varying levels of "security".
+
+First of all, however, you I<can't> take away read permission, because
+the source code has to be readable in order to be compiled and
+interpreted. (That doesn't mean that a CGI script's source is
+readable by people on the web, though--only by people with access to
+the filesystem.) So you have to leave the permissions at the socially
+friendly 0755 level.
+
+Some people regard this as a security problem. If your program does
+insecure things and relies on people not knowing how to exploit those
+insecurities, it is not secure. It is often possible for someone to
+determine the insecure things and exploit them without viewing the
+source. Security through obscurity, the name for hiding your bugs
+instead of fixing them, is little security indeed.
+
+You can try using encryption via source filters (Starting from Perl
+5.8 the Filter::Simple and Filter::Util::Call modules are included in
+the standard distribution), but any decent programmer will be able to
+decrypt it. You can try using the byte code compiler and interpreter
+described later in L<perlfaq3>, but the curious might still be able to
+de-compile it. You can try using the native-code compiler described
+later, but crackers might be able to disassemble it. These pose
+varying degrees of difficulty to people wanting to get at your code,
+but none can definitively conceal it (true of every language, not just
+Perl).
+
+It is very easy to recover the source of Perl programs. You simply
+feed the program to the perl interpreter and use the modules in
+the B:: hierarchy. The B::Deparse module should be able to
+defeat most attempts to hide source. Again, this is not
+unique to Perl.
+
+If you're concerned about people profiting from your code, then the
+bottom line is that nothing but a restrictive license will give you
+legal security. License your software and pepper it with threatening
+statements like "This is unpublished proprietary software of XYZ Corp.
+Your access to it does not give you permission to use it blah blah
+blah." We are not lawyers, of course, so you should see a lawyer if
+you want to be sure your license's wording will stand up in court.
+
+=head2 How can I compile my Perl program into byte code or C?
+
+(contributed by brian d foy)
+
+In general, you can't do this. There are some things that may work
+for your situation though. People usually ask this question
+because they want to distribute their works without giving away
+the source code, and most solutions trade disk space for convenience.
+You probably won't see much of a speed increase either, since most
+solutions simply bundle a Perl interpreter in the final product
+(but see L<How can I make my Perl program run faster?>).
+
+The Perl Archive Toolkit ( http://par.perl.org/ ) is Perl's
+analog to Java's JAR. It's freely available and on CPAN (
+http://search.cpan.org/dist/PAR/ ).
+
+There are also some commercial products that may work for you, although
+you have to buy a license for them.
+
+The Perl Dev Kit ( http://www.activestate.com/Products/Perl_Dev_Kit/ )
+from ActiveState can "Turn your Perl programs into ready-to-run
+executables for HP-UX, Linux, Solaris and Windows."
+
+Perl2Exe ( http://www.indigostar.com/perl2exe.htm ) is a command line
+program for converting perl scripts to executable files. It targets both
+Windows and Unix platforms.
+
+=head2 How can I get C<#!perl> to work on [MS-DOS,NT,...]?
+
+For OS/2 just use
+
+ extproc perl -S -your_switches
+
+as the first line in C<*.cmd> file (C<-S> due to a bug in cmd.exe's
+"extproc" handling). For DOS one should first invent a corresponding
+batch file and codify it in C<ALTERNATE_SHEBANG> (see the
+F<dosish.h> file in the source distribution for more information).
+
+The Win95/NT installation, when using the ActiveState port of Perl,
+will modify the Registry to associate the C<.pl> extension with the
+perl interpreter. If you install another port, perhaps even building
+your own Win95/NT Perl from the standard sources by using a Windows port
+of gcc (e.g., with cygwin or mingw32), then you'll have to modify
+the Registry yourself. In addition to associating C<.pl> with the
+interpreter, NT people can use: C<SET PATHEXT=%PATHEXT%;.PL> to let them
+run the program C<install-linux.pl> merely by typing C<install-linux>.
+
+Under "Classic" MacOS, a perl program will have the appropriate Creator and
+Type, so that double-clicking them will invoke the MacPerl application.
+Under Mac OS X, clickable apps can be made from any C<#!> script using Wil
+Sanchez' DropScript utility: http://www.wsanchez.net/software/ .
+
+I<IMPORTANT!>: Whatever you do, PLEASE don't get frustrated, and just
+throw the perl interpreter into your cgi-bin directory, in order to
+get your programs working for a web server. This is an EXTREMELY big
+security risk. Take the time to figure out how to do it correctly.
+
+=head2 Can I write useful Perl programs on the command line?
+
+Yes. Read L<perlrun> for more information. Some examples follow.
+(These assume standard Unix shell quoting rules.)
+
+ # sum first and last fields
+ perl -lane 'print $F[0] + $F[-1]' *
+
+ # identify text files
+ perl -le 'for(@ARGV) {print if -f && -T _}' *
+
+ # remove (most) comments from C program
+ perl -0777 -pe 's{/\*.*?\*/}{}gs' foo.c
+
+ # make file a month younger than today, defeating reaper daemons
+ perl -e '$X=24*60*60; utime(time(),time() + 30 * $X,@ARGV)' *
+
+ # find first unused uid
+ perl -le '$i++ while getpwuid($i); print $i'
+
+ # display reasonable manpath
+ echo $PATH | perl -nl -072 -e '
+ s![^/+]*$!man!&&-d&&!$s{$_}++&&push@m,$_;END{print"@m"}'
+
+OK, the last one was actually an Obfuscated Perl Contest entry. :-)
+
+=head2 Why don't Perl one-liners work on my DOS/Mac/VMS system?
+
+The problem is usually that the command interpreters on those systems
+have rather different ideas about quoting than the Unix shells under
+which the one-liners were created. On some systems, you may have to
+change single-quotes to double ones, which you must I<NOT> do on Unix
+or Plan9 systems. You might also have to change a single % to a %%.
+
+For example:
+
+ # Unix (including Mac OS X)
+ perl -e 'print "Hello world\n"'
+
+ # DOS, etc.
+ perl -e "print \"Hello world\n\""
+
+ # Mac Classic
+ print "Hello world\n"
+ (then Run "Myscript" or Shift-Command-R)
+
+ # MPW
+ perl -e 'print "Hello world\n"'
+
+ # VMS
+ perl -e "print ""Hello world\n"""
+
+The problem is that none of these examples are reliable: they depend on the
+command interpreter. Under Unix, the first two often work. Under DOS,
+it's entirely possible that neither works. If 4DOS was the command shell,
+you'd probably have better luck like this:
+
+ perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""
+
+Under the Mac, it depends which environment you are using. The MacPerl
+shell, or MPW, is much like Unix shells in its support for several
+quoting variants, except that it makes free use of the Mac's non-ASCII
+characters as control characters.
+
+Using qq(), q(), and qx(), instead of "double quotes", 'single
+quotes', and `backticks`, may make one-liners easier to write.
+
+There is no general solution to all of this. It is a mess.
+
+[Some of this answer was contributed by Kenneth Albanowski.]
+
+=head2 Where can I learn about CGI or Web programming in Perl?
+
+For modules, get the CGI or LWP modules from CPAN. For textbooks,
+see the two especially dedicated to web stuff in the question on
+books. For problems and questions related to the web, like "Why
+do I get 500 Errors" or "Why doesn't it run from the browser right
+when it runs fine on the command line", see the troubleshooting
+guides and references in L<perlfaq9> or in the CGI MetaFAQ:
+
+ http://www.perl.org/CGI_MetaFAQ.html
+
+=head2 Where can I learn about object-oriented Perl programming?
+
+A good place to start is L<perltoot>, and you can use L<perlobj>,
+L<perlboot>, L<perltoot>, L<perltooc>, and L<perlbot> for reference.
+
+A good book on OO on Perl is the "Object-Oriented Perl"
+by Damian Conway from Manning Publications, or "Intermediate Perl"
+by Randal Schwartz, brian d foy, and Tom Phoenix from O'Reilly Media.
+
+=head2 Where can I learn about linking C with Perl?
+
+If you want to call C from Perl, start with L<perlxstut>,
+moving on to L<perlxs>, L<xsubpp>, and L<perlguts>. If you want to
+call Perl from C, then read L<perlembed>, L<perlcall>, and
+L<perlguts>. Don't forget that you can learn a lot from looking at
+how the authors of existing extension modules wrote their code and
+solved their problems.
+
+You might not need all the power of XS. The Inline::C module lets
+you put C code directly in your Perl source. It handles all the
+magic to make it work. You still have to learn at least some of
+the perl API but you won't have to deal with the complexity of the
+XS support files.
+
+=head2 I've read perlembed, perlguts, etc., but I can't embed perl in my C program; what am I doing wrong?
+
+Download the ExtUtils::Embed kit from CPAN and run `make test'. If
+the tests pass, read the pods again and again and again. If they
+fail, see L<perlbug> and send a bug report with the output of
+C<make test TEST_VERBOSE=1> along with C<perl -V>.
+
+=head2 When I tried to run my script, I got this message. What does it mean?
+
+A complete list of Perl's error messages and warnings with explanatory
+text can be found in L<perldiag>. You can also use the splain program
+(distributed with Perl) to explain the error messages:
+
+ perl program 2>diag.out
+ splain [-v] [-p] diag.out
+
+or change your program to explain the messages for you:
+
+ use diagnostics;
+
+or
+
+ use diagnostics -verbose;
+
+=head2 What's MakeMaker?
+
+(contributed by brian d foy)
+
+The C<ExtUtils::MakeMaker> module, better known simply as "MakeMaker",
+turns a Perl script, typically called C<Makefile.PL>, into a Makefile.
+The Unix tool C<make> uses this file to manage dependencies and actions
+to process and install a Perl distribution.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples here are in the public
+domain. You are permitted and encouraged to use this code and any
+derivatives thereof in your own programs for fun or for profit as you
+see fit. A simple comment in the code giving credit to the FAQ would
+be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq4.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq4.pod
new file mode 100644
index 00000000000..45cc9e044dd
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq4.pod
@@ -0,0 +1,2588 @@
+=head1 NAME
+
+perlfaq4 - Data Manipulation
+
+=head1 DESCRIPTION
+
+This section of the FAQ answers questions related to manipulating
+numbers, dates, strings, arrays, hashes, and miscellaneous data issues.
+
+=head1 Data: Numbers
+
+=head2 Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?
+
+For the long explanation, see David Goldberg's "What Every Computer
+Scientist Should Know About Floating-Point Arithmetic"
+(http://docs.sun.com/source/806-3568/ncg_goldberg.html).
+
+Internally, your computer represents floating-point numbers in binary.
+Digital (as in powers of two) computers cannot store all numbers
+exactly. Some real numbers lose precision in the process. This is a
+problem with how computers store numbers and affects all computer
+languages, not just Perl.
+
+L<perlnumber> shows the gory details of number representations and
+conversions.
+
+To limit the number of decimal places in your numbers, you can use the
+C<printf> or C<sprintf> function. See the L<"Floating Point
+Arithmetic"|perlop> for more details.
+
+ printf "%.2f", 10/3;
+
+ my $number = sprintf "%.2f", 10/3;
+
+=head2 Why is int() broken?
+
+Your C<int()> is most probably working just fine. It's the numbers that
+aren't quite what you think.
+
+First, see the answer to "Why am I getting long decimals
+(eg, 19.9499999999999) instead of the numbers I should be getting
+(eg, 19.95)?".
+
+For example, this
+
+ print int(0.6/0.2-2), "\n";
+
+will in most computers print 0, not 1, because even such simple
+numbers as 0.6 and 0.2 cannot be presented exactly by floating-point
+numbers. What you think in the above as 'three' is really more like
+2.9999999999999995559.
+
+=head2 Why isn't my octal data interpreted correctly?
+
+(contributed by brian d foy)
+
+You're probably trying to convert a string to a number, which Perl only
+converts as a decimal number. When Perl converts a string to a number, it
+ignores leading spaces and zeroes, then assumes the rest of the digits
+are in base 10:
+
+ my $string = '0644';
+
+ print $string + 0; # prints 644
+
+ print $string + 44; # prints 688, certainly not octal!
+
+This problem usually involves one of the Perl built-ins that has the
+same name a Unix command that uses octal numbers as arguments on the
+command line. In this example, C<chmod> on the command line knows that
+its first argument is octal because that's what it does:
+
+ %prompt> chmod 644 file
+
+If you want to use the same literal digits (644) in Perl, you have to tell
+Perl to treat them as octal numbers either by prefixing the digits with
+a C<0> or using C<oct>:
+
+ chmod( 0644, $file); # right, has leading zero
+ chmod( oct(644), $file ); # also correct
+
+The problem comes in when you take your numbers from something that Perl
+thinks is a string, such as a command line argument in C<@ARGV>:
+
+ chmod( $ARGV[0], $file); # wrong, even if "0644"
+
+ chmod( oct($ARGV[0]), $file ); # correct, treat string as octal
+
+You can always check the value you're using by printing it in octal
+notation to ensure it matches what you think it should be. Print it
+in octal and decimal format:
+
+ printf "0%o %d", $number, $number;
+
+=head2 Does Perl have a round() function? What about ceil() and floor()? Trig functions?
+
+Remember that C<int()> merely truncates toward 0. For rounding to a
+certain number of digits, C<sprintf()> or C<printf()> is usually the
+easiest route.
+
+ printf("%.3f", 3.1415926535); # prints 3.142
+
+The C<POSIX> module (part of the standard Perl distribution)
+implements C<ceil()>, C<floor()>, and a number of other mathematical
+and trigonometric functions.
+
+ use POSIX;
+ $ceil = ceil(3.5); # 4
+ $floor = floor(3.5); # 3
+
+In 5.000 to 5.003 perls, trigonometry was done in the C<Math::Complex>
+module. With 5.004, the C<Math::Trig> module (part of the standard Perl
+distribution) implements the trigonometric functions. Internally it
+uses the C<Math::Complex> module and some functions can break out from
+the real axis into the complex plane, for example the inverse sine of
+2.
+
+Rounding in financial applications can have serious implications, and
+the rounding method used should be specified precisely. In these
+cases, it probably pays not to trust whichever system rounding is
+being used by Perl, but to instead implement the rounding function you
+need yourself.
+
+To see why, notice how you'll still have an issue on half-way-point
+alternation:
+
+ for ($i = 0; $i < 1.01; $i += 0.05) { printf "%.1f ",$i}
+
+ 0.0 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7
+ 0.8 0.8 0.9 0.9 1.0 1.0
+
+Don't blame Perl. It's the same as in C. IEEE says we have to do
+this. Perl numbers whose absolute values are integers under 2**31 (on
+32 bit machines) will work pretty much like mathematical integers.
+Other numbers are not guaranteed.
+
+=head2 How do I convert between numeric representations/bases/radixes?
+
+As always with Perl there is more than one way to do it. Below are a
+few examples of approaches to making common conversions between number
+representations. This is intended to be representational rather than
+exhaustive.
+
+Some of the examples later in L<perlfaq4> use the C<Bit::Vector>
+module from CPAN. The reason you might choose C<Bit::Vector> over the
+perl built in functions is that it works with numbers of ANY size,
+that it is optimized for speed on some operations, and for at least
+some programmers the notation might be familiar.
+
+=over 4
+
+=item How do I convert hexadecimal into decimal
+
+Using perl's built in conversion of C<0x> notation:
+
+ $dec = 0xDEADBEEF;
+
+Using the C<hex> function:
+
+ $dec = hex("DEADBEEF");
+
+Using C<pack>:
+
+ $dec = unpack("N", pack("H8", substr("0" x 8 . "DEADBEEF", -8)));
+
+Using the CPAN module C<Bit::Vector>:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new_Hex(32, "DEADBEEF");
+ $dec = $vec->to_Dec();
+
+=item How do I convert from decimal to hexadecimal
+
+Using C<sprintf>:
+
+ $hex = sprintf("%X", 3735928559); # upper case A-F
+ $hex = sprintf("%x", 3735928559); # lower case a-f
+
+Using C<unpack>:
+
+ $hex = unpack("H*", pack("N", 3735928559));
+
+Using C<Bit::Vector>:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new_Dec(32, -559038737);
+ $hex = $vec->to_Hex();
+
+And C<Bit::Vector> supports odd bit counts:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new_Dec(33, 3735928559);
+ $vec->Resize(32); # suppress leading 0 if unwanted
+ $hex = $vec->to_Hex();
+
+=item How do I convert from octal to decimal
+
+Using Perl's built in conversion of numbers with leading zeros:
+
+ $dec = 033653337357; # note the leading 0!
+
+Using the C<oct> function:
+
+ $dec = oct("33653337357");
+
+Using C<Bit::Vector>:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new(32);
+ $vec->Chunk_List_Store(3, split(//, reverse "33653337357"));
+ $dec = $vec->to_Dec();
+
+=item How do I convert from decimal to octal
+
+Using C<sprintf>:
+
+ $oct = sprintf("%o", 3735928559);
+
+Using C<Bit::Vector>:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new_Dec(32, -559038737);
+ $oct = reverse join('', $vec->Chunk_List_Read(3));
+
+=item How do I convert from binary to decimal
+
+Perl 5.6 lets you write binary numbers directly with
+the C<0b> notation:
+
+ $number = 0b10110110;
+
+Using C<oct>:
+
+ my $input = "10110110";
+ $decimal = oct( "0b$input" );
+
+Using C<pack> and C<ord>:
+
+ $decimal = ord(pack('B8', '10110110'));
+
+Using C<pack> and C<unpack> for larger strings:
+
+ $int = unpack("N", pack("B32",
+ substr("0" x 32 . "11110101011011011111011101111", -32)));
+ $dec = sprintf("%d", $int);
+
+ # substr() is used to left pad a 32 character string with zeros.
+
+Using C<Bit::Vector>:
+
+ $vec = Bit::Vector->new_Bin(32, "11011110101011011011111011101111");
+ $dec = $vec->to_Dec();
+
+=item How do I convert from decimal to binary
+
+Using C<sprintf> (perl 5.6+):
+
+ $bin = sprintf("%b", 3735928559);
+
+Using C<unpack>:
+
+ $bin = unpack("B*", pack("N", 3735928559));
+
+Using C<Bit::Vector>:
+
+ use Bit::Vector;
+ $vec = Bit::Vector->new_Dec(32, -559038737);
+ $bin = $vec->to_Bin();
+
+The remaining transformations (e.g. hex -> oct, bin -> hex, etc.)
+are left as an exercise to the inclined reader.
+
+=back
+
+=head2 Why doesn't & work the way I want it to?
+
+The behavior of binary arithmetic operators depends on whether they're
+used on numbers or strings. The operators treat a string as a series
+of bits and work with that (the string C<"3"> is the bit pattern
+C<00110011>). The operators work with the binary form of a number
+(the number C<3> is treated as the bit pattern C<00000011>).
+
+So, saying C<11 & 3> performs the "and" operation on numbers (yielding
+C<3>). Saying C<"11" & "3"> performs the "and" operation on strings
+(yielding C<"1">).
+
+Most problems with C<&> and C<|> arise because the programmer thinks
+they have a number but really it's a string. The rest arise because
+the programmer says:
+
+ if ("\020\020" & "\101\101") {
+ # ...
+ }
+
+but a string consisting of two null bytes (the result of C<"\020\020"
+& "\101\101">) is not a false value in Perl. You need:
+
+ if ( ("\020\020" & "\101\101") !~ /[^\000]/) {
+ # ...
+ }
+
+=head2 How do I multiply matrices?
+
+Use the C<Math::Matrix> or C<Math::MatrixReal> modules (available from CPAN)
+or the C<PDL> extension (also available from CPAN).
+
+=head2 How do I perform an operation on a series of integers?
+
+To call a function on each element in an array, and collect the
+results, use:
+
+ @results = map { my_func($_) } @array;
+
+For example:
+
+ @triple = map { 3 * $_ } @single;
+
+To call a function on each element of an array, but ignore the
+results:
+
+ foreach $iterator (@array) {
+ some_func($iterator);
+ }
+
+To call a function on each integer in a (small) range, you B<can> use:
+
+ @results = map { some_func($_) } (5 .. 25);
+
+but you should be aware that the C<..> operator creates an array of
+all integers in the range. This can take a lot of memory for large
+ranges. Instead use:
+
+ @results = ();
+ for ($i=5; $i < 500_005; $i++) {
+ push(@results, some_func($i));
+ }
+
+This situation has been fixed in Perl5.005. Use of C<..> in a C<for>
+loop will iterate over the range, without creating the entire range.
+
+ for my $i (5 .. 500_005) {
+ push(@results, some_func($i));
+ }
+
+will not create a list of 500,000 integers.
+
+=head2 How can I output Roman numerals?
+
+Get the L<http://www.cpan.org/modules/by-module/Roman> module.
+
+=head2 Why aren't my random numbers random?
+
+If you're using a version of Perl before 5.004, you must call C<srand>
+once at the start of your program to seed the random number generator.
+
+ BEGIN { srand() if $] < 5.004 }
+
+5.004 and later automatically call C<srand> at the beginning. Don't
+call C<srand> more than once--you make your numbers less random,
+rather than more.
+
+Computers are good at being predictable and bad at being random
+(despite appearances caused by bugs in your programs :-). see the
+F<random> article in the "Far More Than You Ever Wanted To Know"
+collection in L<http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz>, courtesy
+of Tom Phoenix, talks more about this. John von Neumann said, "Anyone
+who attempts to generate random numbers by deterministic means is, of
+course, living in a state of sin."
+
+If you want numbers that are more random than C<rand> with C<srand>
+provides, you should also check out the C<Math::TrulyRandom> module from
+CPAN. It uses the imperfections in your system's timer to generate
+random numbers, but this takes quite a while. If you want a better
+pseudorandom generator than comes with your operating system, look at
+"Numerical Recipes in C" at L<http://www.nr.com/>.
+
+=head2 How do I get a random number between X and Y?
+
+To get a random number between two values, you can use the C<rand()>
+built-in to get a random number between 0 and 1. From there, you shift
+that into the range that you want.
+
+C<rand($x)> returns a number such that C<< 0 <= rand($x) < $x >>. Thus
+what you want to have perl figure out is a random number in the range
+from 0 to the difference between your I<X> and I<Y>.
+
+That is, to get a number between 10 and 15, inclusive, you want a
+random number between 0 and 5 that you can then add to 10.
+
+ my $number = 10 + int rand( 15-10+1 ); # ( 10,11,12,13,14, or 15 )
+
+Hence you derive the following simple function to abstract
+that. It selects a random integer between the two given
+integers (inclusive), For example: C<random_int_between(50,120)>.
+
+ sub random_int_between {
+ my($min, $max) = @_;
+ # Assumes that the two arguments are integers themselves!
+ return $min if $min == $max;
+ ($min, $max) = ($max, $min) if $min > $max;
+ return $min + int rand(1 + $max - $min);
+ }
+
+=head1 Data: Dates
+
+=head2 How do I find the day or week of the year?
+
+The C<localtime> function returns the day of the year. Without an
+argument C<localtime> uses the current time.
+
+ $day_of_year = (localtime)[7];
+
+The C<POSIX> module can also format a date as the day of the year or
+week of the year.
+
+ use POSIX qw/strftime/;
+ my $day_of_year = strftime "%j", localtime;
+ my $week_of_year = strftime "%W", localtime;
+
+To get the day of year for any date, use C<POSIX>'s C<mktime> to get
+a time in epoch seconds for the argument to C<localtime>.
+
+ use POSIX qw/mktime strftime/;
+ my $week_of_year = strftime "%W",
+ localtime( mktime( 0, 0, 0, 18, 11, 87 ) );
+
+The C<Date::Calc> module provides two functions to calculate these.
+
+ use Date::Calc;
+ my $day_of_year = Day_of_Year( 1987, 12, 18 );
+ my $week_of_year = Week_of_Year( 1987, 12, 18 );
+
+=head2 How do I find the current century or millennium?
+
+Use the following simple functions:
+
+ sub get_century {
+ return int((((localtime(shift || time))[5] + 1999))/100);
+ }
+
+ sub get_millennium {
+ return 1+int((((localtime(shift || time))[5] + 1899))/1000);
+ }
+
+On some systems, the C<POSIX> module's C<strftime()> function has been
+extended in a non-standard way to use a C<%C> format, which they
+sometimes claim is the "century". It isn't, because on most such
+systems, this is only the first two digits of the four-digit year, and
+thus cannot be used to reliably determine the current century or
+millennium.
+
+=head2 How can I compare two dates and find the difference?
+
+(contributed by brian d foy)
+
+You could just store all your dates as a number and then subtract.
+Life isn't always that simple though. If you want to work with
+formatted dates, the C<Date::Manip>, C<Date::Calc>, or C<DateTime>
+modules can help you.
+
+=head2 How can I take a string and turn it into epoch seconds?
+
+If it's a regular enough string that it always has the same format,
+you can split it up and pass the parts to C<timelocal> in the standard
+C<Time::Local> module. Otherwise, you should look into the C<Date::Calc>
+and C<Date::Manip> modules from CPAN.
+
+=head2 How can I find the Julian Day?
+
+(contributed by brian d foy and Dave Cross)
+
+You can use the C<Time::JulianDay> module available on CPAN. Ensure
+that you really want to find a Julian day, though, as many people have
+different ideas about Julian days. See
+http://www.hermetic.ch/cal_stud/jdn.htm for instance.
+
+You can also try the C<DateTime> module, which can convert a date/time
+to a Julian Day.
+
+ $ perl -MDateTime -le'print DateTime->today->jd'
+ 2453401.5
+
+Or the modified Julian Day
+
+ $ perl -MDateTime -le'print DateTime->today->mjd'
+ 53401
+
+Or even the day of the year (which is what some people think of as a
+Julian day)
+
+ $ perl -MDateTime -le'print DateTime->today->doy'
+ 31
+
+=head2 How do I find yesterday's date?
+X<date> X<yesterday> X<DateTime> X<Date::Calc> X<Time::Local>
+X<daylight saving time> X<day> X<Today_and_Now> X<localtime>
+X<timelocal>
+
+(contributed by brian d foy)
+
+Use one of the Date modules. The C<DateTime> module makes it simple, and
+give you the same time of day, only the day before.
+
+ use DateTime;
+
+ my $yesterday = DateTime->now->subtract( days => 1 );
+
+ print "Yesterday was $yesterday\n";
+
+You can also use the C<Date::Calc> module using its C<Today_and_Now>
+function.
+
+ use Date::Calc qw( Today_and_Now Add_Delta_DHMS );
+
+ my @date_time = Add_Delta_DHMS( Today_and_Now(), -1, 0, 0, 0 );
+
+ print "@date_time\n";
+
+Most people try to use the time rather than the calendar to figure out
+dates, but that assumes that days are twenty-four hours each. For
+most people, there are two days a year when they aren't: the switch to
+and from summer time throws this off. Let the modules do the work.
+
+If you absolutely must do it yourself (or can't use one of the
+modules), here's a solution using C<Time::Local>, which comes with
+Perl:
+
+ # contributed by Gunnar Hjalmarsson
+ use Time::Local;
+ my $today = timelocal 0, 0, 12, ( localtime )[3..5];
+ my ($d, $m, $y) = ( localtime $today-86400 )[3..5];
+ printf "Yesterday: %d-%02d-%02d\n", $y+1900, $m+1, $d;
+
+In this case, you measure the day starting at noon, and subtract 24
+hours. Even if the length of the calendar day is 23 or 25 hours,
+you'll still end up on the previous calendar day, although not at
+noon. Since you don't care about the time, the one hour difference
+doesn't matter and you end up with the previous date.
+
+=head2 Does Perl have a Year 2000 or 2038 problem? Is Perl Y2K compliant?
+
+(contributed by brian d foy)
+
+Perl itself never had a Y2K problem, although that never stopped people
+from creating Y2K problems on their own. See the documentation for
+C<localtime> for its proper use.
+
+Starting with Perl 5.11, C<localtime> and C<gmtime> can handle dates past
+03:14:08 January 19, 2038, when a 32-bit based time would overflow. You
+still might get a warning on a 32-bit C<perl>:
+
+ % perl5.11.2 -E 'say scalar localtime( 0x9FFF_FFFFFFFF )'
+ Integer overflow in hexadecimal number at -e line 1.
+ Wed Nov 1 19:42:39 5576711
+
+On a 64-bit C<perl>, you can get even larger dates for those really long
+running projects:
+
+ % perl5.11.2 -E 'say scalar gmtime( 0x9FFF_FFFFFFFF )'
+ Thu Nov 2 00:42:39 5576711
+
+You're still out of luck if you need to keep tracking of decaying protons
+though.
+
+=head1 Data: Strings
+
+=head2 How do I validate input?
+
+(contributed by brian d foy)
+
+There are many ways to ensure that values are what you expect or
+want to accept. Besides the specific examples that we cover in the
+perlfaq, you can also look at the modules with "Assert" and "Validate"
+in their names, along with other modules such as C<Regexp::Common>.
+
+Some modules have validation for particular types of input, such
+as C<Business::ISBN>, C<Business::CreditCard>, C<Email::Valid>,
+and C<Data::Validate::IP>.
+
+=head2 How do I unescape a string?
+
+It depends just what you mean by "escape". URL escapes are dealt
+with in L<perlfaq9>. Shell escapes with the backslash (C<\>)
+character are removed with
+
+ s/\\(.)/$1/g;
+
+This won't expand C<"\n"> or C<"\t"> or any other special escapes.
+
+=head2 How do I remove consecutive pairs of characters?
+
+(contributed by brian d foy)
+
+You can use the substitution operator to find pairs of characters (or
+runs of characters) and replace them with a single instance. In this
+substitution, we find a character in C<(.)>. The memory parentheses
+store the matched character in the back-reference C<\1> and we use
+that to require that the same thing immediately follow it. We replace
+that part of the string with the character in C<$1>.
+
+ s/(.)\1/$1/g;
+
+We can also use the transliteration operator, C<tr///>. In this
+example, the search list side of our C<tr///> contains nothing, but
+the C<c> option complements that so it contains everything. The
+replacement list also contains nothing, so the transliteration is
+almost a no-op since it won't do any replacements (or more exactly,
+replace the character with itself). However, the C<s> option squashes
+duplicated and consecutive characters in the string so a character
+does not show up next to itself
+
+ my $str = 'Haarlem'; # in the Netherlands
+ $str =~ tr///cs; # Now Harlem, like in New York
+
+=head2 How do I expand function calls in a string?
+
+(contributed by brian d foy)
+
+This is documented in L<perlref>, and although it's not the easiest
+thing to read, it does work. In each of these examples, we call the
+function inside the braces used to dereference a reference. If we
+have more than one return value, we can construct and dereference an
+anonymous array. In this case, we call the function in list context.
+
+ print "The time values are @{ [localtime] }.\n";
+
+If we want to call the function in scalar context, we have to do a bit
+more work. We can really have any code we like inside the braces, so
+we simply have to end with the scalar reference, although how you do
+that is up to you, and you can use code inside the braces. Note that
+the use of parens creates a list context, so we need C<scalar> to
+force the scalar context on the function:
+
+ print "The time is ${\(scalar localtime)}.\n"
+
+ print "The time is ${ my $x = localtime; \$x }.\n";
+
+If your function already returns a reference, you don't need to create
+the reference yourself.
+
+ sub timestamp { my $t = localtime; \$t }
+
+ print "The time is ${ timestamp() }.\n";
+
+The C<Interpolation> module can also do a lot of magic for you. You can
+specify a variable name, in this case C<E>, to set up a tied hash that
+does the interpolation for you. It has several other methods to do this
+as well.
+
+ use Interpolation E => 'eval';
+ print "The time values are $E{localtime()}.\n";
+
+In most cases, it is probably easier to simply use string concatenation,
+which also forces scalar context.
+
+ print "The time is " . localtime() . ".\n";
+
+=head2 How do I find matching/nesting anything?
+
+This isn't something that can be done in one regular expression, no
+matter how complicated. To find something between two single
+characters, a pattern like C</x([^x]*)x/> will get the intervening
+bits in $1. For multiple ones, then something more like
+C</alpha(.*?)omega/> would be needed. But none of these deals with
+nested patterns. For balanced expressions using C<(>, C<{>, C<[> or
+C<< < >> as delimiters, use the CPAN module Regexp::Common, or see
+L<perlre/(??{ code })>. For other cases, you'll have to write a
+parser.
+
+If you are serious about writing a parser, there are a number of
+modules or oddities that will make your life a lot easier. There are
+the CPAN modules C<Parse::RecDescent>, C<Parse::Yapp>, and
+C<Text::Balanced>; and the C<byacc> program. Starting from perl 5.8
+the C<Text::Balanced> is part of the standard distribution.
+
+One simple destructive, inside-out approach that you might try is to
+pull out the smallest nesting parts one at a time:
+
+ while (s/BEGIN((?:(?!BEGIN)(?!END).)*)END//gs) {
+ # do something with $1
+ }
+
+A more complicated and sneaky approach is to make Perl's regular
+expression engine do it for you. This is courtesy Dean Inada, and
+rather has the nature of an Obfuscated Perl Contest entry, but it
+really does work:
+
+ # $_ contains the string to parse
+ # BEGIN and END are the opening and closing markers for the
+ # nested text.
+
+ @( = ('(','');
+ @) = (')','');
+ ($re=$_)=~s/((BEGIN)|(END)|.)/$)[!$3]\Q$1\E$([!$2]/gs;
+ @$ = (eval{/$re/},$@!~/unmatched/i);
+ print join("\n",@$[0..$#$]) if( $$[-1] );
+
+=head2 How do I reverse a string?
+
+Use C<reverse()> in scalar context, as documented in
+L<perlfunc/reverse>.
+
+ $reversed = reverse $string;
+
+=head2 How do I expand tabs in a string?
+
+You can do it yourself:
+
+ 1 while $string =~ s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e;
+
+Or you can just use the C<Text::Tabs> module (part of the standard Perl
+distribution).
+
+ use Text::Tabs;
+ @expanded_lines = expand(@lines_with_tabs);
+
+=head2 How do I reformat a paragraph?
+
+Use C<Text::Wrap> (part of the standard Perl distribution):
+
+ use Text::Wrap;
+ print wrap("\t", ' ', @paragraphs);
+
+The paragraphs you give to C<Text::Wrap> should not contain embedded
+newlines. C<Text::Wrap> doesn't justify the lines (flush-right).
+
+Or use the CPAN module C<Text::Autoformat>. Formatting files can be
+easily done by making a shell alias, like so:
+
+ alias fmt="perl -i -MText::Autoformat -n0777 \
+ -e 'print autoformat $_, {all=>1}' $*"
+
+See the documentation for C<Text::Autoformat> to appreciate its many
+capabilities.
+
+=head2 How can I access or change N characters of a string?
+
+You can access the first characters of a string with substr().
+To get the first character, for example, start at position 0
+and grab the string of length 1.
+
+
+ $string = "Just another Perl Hacker";
+ $first_char = substr( $string, 0, 1 ); # 'J'
+
+To change part of a string, you can use the optional fourth
+argument which is the replacement string.
+
+ substr( $string, 13, 4, "Perl 5.8.0" );
+
+You can also use substr() as an lvalue.
+
+ substr( $string, 13, 4 ) = "Perl 5.8.0";
+
+=head2 How do I change the Nth occurrence of something?
+
+You have to keep track of N yourself. For example, let's say you want
+to change the fifth occurrence of C<"whoever"> or C<"whomever"> into
+C<"whosoever"> or C<"whomsoever">, case insensitively. These
+all assume that $_ contains the string to be altered.
+
+ $count = 0;
+ s{((whom?)ever)}{
+ ++$count == 5 # is it the 5th?
+ ? "${2}soever" # yes, swap
+ : $1 # renege and leave it there
+ }ige;
+
+In the more general case, you can use the C</g> modifier in a C<while>
+loop, keeping count of matches.
+
+ $WANT = 3;
+ $count = 0;
+ $_ = "One fish two fish red fish blue fish";
+ while (/(\w+)\s+fish\b/gi) {
+ if (++$count == $WANT) {
+ print "The third fish is a $1 one.\n";
+ }
+ }
+
+That prints out: C<"The third fish is a red one."> You can also use a
+repetition count and repeated pattern like this:
+
+ /(?:\w+\s+fish\s+){2}(\w+)\s+fish/i;
+
+=head2 How can I count the number of occurrences of a substring within a string?
+
+There are a number of ways, with varying efficiency. If you want a
+count of a certain single character (X) within a string, you can use the
+C<tr///> function like so:
+
+ $string = "ThisXlineXhasXsomeXx'sXinXit";
+ $count = ($string =~ tr/X//);
+ print "There are $count X characters in the string";
+
+This is fine if you are just looking for a single character. However,
+if you are trying to count multiple character substrings within a
+larger string, C<tr///> won't work. What you can do is wrap a while()
+loop around a global pattern match. For example, let's count negative
+integers:
+
+ $string = "-9 55 48 -2 23 -76 4 14 -44";
+ while ($string =~ /-\d+/g) { $count++ }
+ print "There are $count negative numbers in the string";
+
+Another version uses a global match in list context, then assigns the
+result to a scalar, producing a count of the number of matches.
+
+ $count = () = $string =~ /-\d+/g;
+
+=head2 How do I capitalize all the words on one line?
+X<Text::Autoformat> X<capitalize> X<case, title> X<case, sentence>
+
+(contributed by brian d foy)
+
+Damian Conway's L<Text::Autoformat> handles all of the thinking
+for you.
+
+ use Text::Autoformat;
+ my $x = "Dr. Strangelove or: How I Learned to Stop ".
+ "Worrying and Love the Bomb";
+
+ print $x, "\n";
+ for my $style (qw( sentence title highlight )) {
+ print autoformat($x, { case => $style }), "\n";
+ }
+
+How do you want to capitalize those words?
+
+ FRED AND BARNEY'S LODGE # all uppercase
+ Fred And Barney's Lodge # title case
+ Fred and Barney's Lodge # highlight case
+
+It's not as easy a problem as it looks. How many words do you think
+are in there? Wait for it... wait for it.... If you answered 5
+you're right. Perl words are groups of C<\w+>, but that's not what
+you want to capitalize. How is Perl supposed to know not to capitalize
+that C<s> after the apostrophe? You could try a regular expression:
+
+ $string =~ s/ (
+ (^\w) #at the beginning of the line
+ | # or
+ (\s\w) #preceded by whitespace
+ )
+ /\U$1/xg;
+
+ $string =~ s/([\w']+)/\u\L$1/g;
+
+Now, what if you don't want to capitalize that "and"? Just use
+L<Text::Autoformat> and get on with the next problem. :)
+
+=head2 How can I split a [character] delimited string except when inside [character]?
+
+Several modules can handle this sort of parsing--C<Text::Balanced>,
+C<Text::CSV>, C<Text::CSV_XS>, and C<Text::ParseWords>, among others.
+
+Take the example case of trying to split a string that is
+comma-separated into its different fields. You can't use C<split(/,/)>
+because you shouldn't split if the comma is inside quotes. For
+example, take a data line like this:
+
+ SAR001,"","Cimetrix, Inc","Bob Smith","CAM",N,8,1,0,7,"Error, Core Dumped"
+
+Due to the restriction of the quotes, this is a fairly complex
+problem. Thankfully, we have Jeffrey Friedl, author of
+I<Mastering Regular Expressions>, to handle these for us. He
+suggests (assuming your string is contained in C<$text>):
+
+ @new = ();
+ push(@new, $+) while $text =~ m{
+ "([^\"\\]*(?:\\.[^\"\\]*)*)",? # groups the phrase inside the quotes
+ | ([^,]+),?
+ | ,
+ }gx;
+ push(@new, undef) if substr($text,-1,1) eq ',';
+
+If you want to represent quotation marks inside a
+quotation-mark-delimited field, escape them with backslashes (eg,
+C<"like \"this\"">.
+
+Alternatively, the C<Text::ParseWords> module (part of the standard
+Perl distribution) lets you say:
+
+ use Text::ParseWords;
+ @new = quotewords(",", 0, $text);
+
+=head2 How do I strip blank space from the beginning/end of a string?
+
+(contributed by brian d foy)
+
+A substitution can do this for you. For a single line, you want to
+replace all the leading or trailing whitespace with nothing. You
+can do that with a pair of substitutions.
+
+ s/^\s+//;
+ s/\s+$//;
+
+You can also write that as a single substitution, although it turns
+out the combined statement is slower than the separate ones. That
+might not matter to you, though.
+
+ s/^\s+|\s+$//g;
+
+In this regular expression, the alternation matches either at the
+beginning or the end of the string since the anchors have a lower
+precedence than the alternation. With the C</g> flag, the substitution
+makes all possible matches, so it gets both. Remember, the trailing
+newline matches the C<\s+>, and the C<$> anchor can match to the
+physical end of the string, so the newline disappears too. Just add
+the newline to the output, which has the added benefit of preserving
+"blank" (consisting entirely of whitespace) lines which the C<^\s+>
+would remove all by itself.
+
+ while( <> )
+ {
+ s/^\s+|\s+$//g;
+ print "$_\n";
+ }
+
+For a multi-line string, you can apply the regular expression
+to each logical line in the string by adding the C</m> flag (for
+"multi-line"). With the C</m> flag, the C<$> matches I<before> an
+embedded newline, so it doesn't remove it. It still removes the
+newline at the end of the string.
+
+ $string =~ s/^\s+|\s+$//gm;
+
+Remember that lines consisting entirely of whitespace will disappear,
+since the first part of the alternation can match the entire string
+and replace it with nothing. If need to keep embedded blank lines,
+you have to do a little more work. Instead of matching any whitespace
+(since that includes a newline), just match the other whitespace.
+
+ $string =~ s/^[\t\f ]+|[\t\f ]+$//mg;
+
+=head2 How do I pad a string with blanks or pad a number with zeroes?
+
+In the following examples, C<$pad_len> is the length to which you wish
+to pad the string, C<$text> or C<$num> contains the string to be padded,
+and C<$pad_char> contains the padding character. You can use a single
+character string constant instead of the C<$pad_char> variable if you
+know what it is in advance. And in the same way you can use an integer in
+place of C<$pad_len> if you know the pad length in advance.
+
+The simplest method uses the C<sprintf> function. It can pad on the left
+or right with blanks and on the left with zeroes and it will not
+truncate the result. The C<pack> function can only pad strings on the
+right with blanks and it will truncate the result to a maximum length of
+C<$pad_len>.
+
+ # Left padding a string with blanks (no truncation):
+ $padded = sprintf("%${pad_len}s", $text);
+ $padded = sprintf("%*s", $pad_len, $text); # same thing
+
+ # Right padding a string with blanks (no truncation):
+ $padded = sprintf("%-${pad_len}s", $text);
+ $padded = sprintf("%-*s", $pad_len, $text); # same thing
+
+ # Left padding a number with 0 (no truncation):
+ $padded = sprintf("%0${pad_len}d", $num);
+ $padded = sprintf("%0*d", $pad_len, $num); # same thing
+
+ # Right padding a string with blanks using pack (will truncate):
+ $padded = pack("A$pad_len",$text);
+
+If you need to pad with a character other than blank or zero you can use
+one of the following methods. They all generate a pad string with the
+C<x> operator and combine that with C<$text>. These methods do
+not truncate C<$text>.
+
+Left and right padding with any character, creating a new string:
+
+ $padded = $pad_char x ( $pad_len - length( $text ) ) . $text;
+ $padded = $text . $pad_char x ( $pad_len - length( $text ) );
+
+Left and right padding with any character, modifying C<$text> directly:
+
+ substr( $text, 0, 0 ) = $pad_char x ( $pad_len - length( $text ) );
+ $text .= $pad_char x ( $pad_len - length( $text ) );
+
+=head2 How do I extract selected columns from a string?
+
+(contributed by brian d foy)
+
+If you know the columns that contain the data, you can
+use C<substr> to extract a single column.
+
+ my $column = substr( $line, $start_column, $length );
+
+You can use C<split> if the columns are separated by whitespace or
+some other delimiter, as long as whitespace or the delimiter cannot
+appear as part of the data.
+
+ my $line = ' fred barney betty ';
+ my @columns = split /\s+/, $line;
+ # ( '', 'fred', 'barney', 'betty' );
+
+ my $line = 'fred||barney||betty';
+ my @columns = split /\|/, $line;
+ # ( 'fred', '', 'barney', '', 'betty' );
+
+If you want to work with comma-separated values, don't do this since
+that format is a bit more complicated. Use one of the modules that
+handle that format, such as C<Text::CSV>, C<Text::CSV_XS>, or
+C<Text::CSV_PP>.
+
+If you want to break apart an entire line of fixed columns, you can use
+C<unpack> with the A (ASCII) format. By using a number after the format
+specifier, you can denote the column width. See the C<pack> and C<unpack>
+entries in L<perlfunc> for more details.
+
+ my @fields = unpack( $line, "A8 A8 A8 A16 A4" );
+
+Note that spaces in the format argument to C<unpack> do not denote literal
+spaces. If you have space separated data, you may want C<split> instead.
+
+=head2 How do I find the soundex value of a string?
+
+(contributed by brian d foy)
+
+You can use the Text::Soundex module. If you want to do fuzzy or close
+matching, you might also try the C<String::Approx>, and
+C<Text::Metaphone>, and C<Text::DoubleMetaphone> modules.
+
+=head2 How can I expand variables in text strings?
+
+(contributed by brian d foy)
+
+If you can avoid it, don't, or if you can use a templating system,
+such as C<Text::Template> or C<Template> Toolkit, do that instead. You
+might even be able to get the job done with C<sprintf> or C<printf>:
+
+ my $string = sprintf 'Say hello to %s and %s', $foo, $bar;
+
+However, for the one-off simple case where I don't want to pull out a
+full templating system, I'll use a string that has two Perl scalar
+variables in it. In this example, I want to expand C<$foo> and C<$bar>
+to their variable's values:
+
+ my $foo = 'Fred';
+ my $bar = 'Barney';
+ $string = 'Say hello to $foo and $bar';
+
+One way I can do this involves the substitution operator and a double
+C</e> flag. The first C</e> evaluates C<$1> on the replacement side and
+turns it into C<$foo>. The second /e starts with C<$foo> and replaces
+it with its value. C<$foo>, then, turns into 'Fred', and that's finally
+what's left in the string:
+
+ $string =~ s/(\$\w+)/$1/eeg; # 'Say hello to Fred and Barney'
+
+The C</e> will also silently ignore violations of strict, replacing
+undefined variable names with the empty string. Since I'm using the
+C</e> flag (twice even!), I have all of the same security problems I
+have with C<eval> in its string form. If there's something odd in
+C<$foo>, perhaps something like C<@{[ system "rm -rf /" ]}>, then
+I could get myself in trouble.
+
+To get around the security problem, I could also pull the values from
+a hash instead of evaluating variable names. Using a single C</e>, I
+can check the hash to ensure the value exists, and if it doesn't, I
+can replace the missing value with a marker, in this case C<???> to
+signal that I missed something:
+
+ my $string = 'This has $foo and $bar';
+
+ my %Replacements = (
+ foo => 'Fred',
+ );
+
+ # $string =~ s/\$(\w+)/$Replacements{$1}/g;
+ $string =~ s/\$(\w+)/
+ exists $Replacements{$1} ? $Replacements{$1} : '???'
+ /eg;
+
+ print $string;
+
+=head2 What's wrong with always quoting "$vars"?
+
+The problem is that those double-quotes force
+stringification--coercing numbers and references into strings--even
+when you don't want them to be strings. Think of it this way:
+double-quote expansion is used to produce new strings. If you already
+have a string, why do you need more?
+
+If you get used to writing odd things like these:
+
+ print "$var"; # BAD
+ $new = "$old"; # BAD
+ somefunc("$var"); # BAD
+
+You'll be in trouble. Those should (in 99.8% of the cases) be
+the simpler and more direct:
+
+ print $var;
+ $new = $old;
+ somefunc($var);
+
+Otherwise, besides slowing you down, you're going to break code when
+the thing in the scalar is actually neither a string nor a number, but
+a reference:
+
+ func(\@array);
+ sub func {
+ my $aref = shift;
+ my $oref = "$aref"; # WRONG
+ }
+
+You can also get into subtle problems on those few operations in Perl
+that actually do care about the difference between a string and a
+number, such as the magical C<++> autoincrement operator or the
+syscall() function.
+
+Stringification also destroys arrays.
+
+ @lines = `command`;
+ print "@lines"; # WRONG - extra blanks
+ print @lines; # right
+
+=head2 Why don't my E<lt>E<lt>HERE documents work?
+
+Check for these three things:
+
+=over 4
+
+=item There must be no space after the E<lt>E<lt> part.
+
+=item There (probably) should be a semicolon at the end.
+
+=item You can't (easily) have any space in front of the tag.
+
+=back
+
+If you want to indent the text in the here document, you
+can do this:
+
+ # all in one
+ ($VAR = <<HERE_TARGET) =~ s/^\s+//gm;
+ your text
+ goes here
+ HERE_TARGET
+
+But the HERE_TARGET must still be flush against the margin.
+If you want that indented also, you'll have to quote
+in the indentation.
+
+ ($quote = <<' FINIS') =~ s/^\s+//gm;
+ ...we will have peace, when you and all your works have
+ perished--and the works of your dark master to whom you
+ would deliver us. You are a liar, Saruman, and a corrupter
+ of men's hearts. --Theoden in /usr/src/perl/taint.c
+ FINIS
+ $quote =~ s/\s+--/\n--/;
+
+A nice general-purpose fixer-upper function for indented here documents
+follows. It expects to be called with a here document as its argument.
+It looks to see whether each line begins with a common substring, and
+if so, strips that substring off. Otherwise, it takes the amount of leading
+whitespace found on the first line and removes that much off each
+subsequent line.
+
+ sub fix {
+ local $_ = shift;
+ my ($white, $leader); # common whitespace and common leading string
+ if (/^\s*(?:([^\w\s]+)(\s*).*\n)(?:\s*\1\2?.*\n)+$/) {
+ ($white, $leader) = ($2, quotemeta($1));
+ } else {
+ ($white, $leader) = (/^(\s+)/, '');
+ }
+ s/^\s*?$leader(?:$white)?//gm;
+ return $_;
+ }
+
+This works with leading special strings, dynamically determined:
+
+ $remember_the_main = fix<<' MAIN_INTERPRETER_LOOP';
+ @@@ int
+ @@@ runops() {
+ @@@ SAVEI32(runlevel);
+ @@@ runlevel++;
+ @@@ while ( op = (*op->op_ppaddr)() );
+ @@@ TAINT_NOT;
+ @@@ return 0;
+ @@@ }
+ MAIN_INTERPRETER_LOOP
+
+Or with a fixed amount of leading whitespace, with remaining
+indentation correctly preserved:
+
+ $poem = fix<<EVER_ON_AND_ON;
+ Now far ahead the Road has gone,
+ And I must follow, if I can,
+ Pursuing it with eager feet,
+ Until it joins some larger way
+ Where many paths and errands meet.
+ And whither then? I cannot say.
+ --Bilbo in /usr/src/perl/pp_ctl.c
+ EVER_ON_AND_ON
+
+=head1 Data: Arrays
+
+=head2 What is the difference between a list and an array?
+
+(contributed by brian d foy)
+
+A list is a fixed collection of scalars. An array is a variable that
+holds a variable collection of scalars. An array can supply its collection
+for list operations, so list operations also work on arrays:
+
+ # slices
+ ( 'dog', 'cat', 'bird' )[2,3];
+ @animals[2,3];
+
+ # iteration
+ foreach ( qw( dog cat bird ) ) { ... }
+ foreach ( @animals ) { ... }
+
+ my @three = grep { length == 3 } qw( dog cat bird );
+ my @three = grep { length == 3 } @animals;
+
+ # supply an argument list
+ wash_animals( qw( dog cat bird ) );
+ wash_animals( @animals );
+
+Array operations, which change the scalars, reaaranges them, or adds
+or subtracts some scalars, only work on arrays. These can't work on a
+list, which is fixed. Array operations include C<shift>, C<unshift>,
+C<push>, C<pop>, and C<splice>.
+
+An array can also change its length:
+
+ $#animals = 1; # truncate to two elements
+ $#animals = 10000; # pre-extend to 10,001 elements
+
+You can change an array element, but you can't change a list element:
+
+ $animals[0] = 'Rottweiler';
+ qw( dog cat bird )[0] = 'Rottweiler'; # syntax error!
+
+ foreach ( @animals ) {
+ s/^d/fr/; # works fine
+ }
+
+ foreach ( qw( dog cat bird ) ) {
+ s/^d/fr/; # Error! Modification of read only value!
+ }
+
+However, if the list element is itself a variable, it appears that you
+can change a list element. However, the list element is the variable, not
+the data. You're not changing the list element, but something the list
+element refers to. The list element itself doesn't change: it's still
+the same variable.
+
+You also have to be careful about context. You can assign an array to
+a scalar to get the number of elements in the array. This only works
+for arrays, though:
+
+ my $count = @animals; # only works with arrays
+
+If you try to do the same thing with what you think is a list, you
+get a quite different result. Although it looks like you have a list
+on the righthand side, Perl actually sees a bunch of scalars separated
+by a comma:
+
+ my $scalar = ( 'dog', 'cat', 'bird' ); # $scalar gets bird
+
+Since you're assigning to a scalar, the righthand side is in scalar
+context. The comma operator (yes, it's an operator!) in scalar
+context evaluates its lefthand side, throws away the result, and
+evaluates it's righthand side and returns the result. In effect,
+that list-lookalike assigns to C<$scalar> it's rightmost value. Many
+people mess this up becuase they choose a list-lookalike whose
+last element is also the count they expect:
+
+ my $scalar = ( 1, 2, 3 ); # $scalar gets 3, accidentally
+
+=head2 What is the difference between $array[1] and @array[1]?
+
+(contributed by brian d foy)
+
+The difference is the sigil, that special character in front of the
+array name. The C<$> sigil means "exactly one item", while the C<@>
+sigil means "zero or more items". The C<$> gets you a single scalar,
+while the C<@> gets you a list.
+
+The confusion arises because people incorrectly assume that the sigil
+denotes the variable type.
+
+The C<$array[1]> is a single-element access to the array. It's going
+to return the item in index 1 (or undef if there is no item there).
+If you intend to get exactly one element from the array, this is the
+form you should use.
+
+The C<@array[1]> is an array slice, although it has only one index.
+You can pull out multiple elements simultaneously by specifying
+additional indices as a list, like C<@array[1,4,3,0]>.
+
+Using a slice on the lefthand side of the assignment supplies list
+context to the righthand side. This can lead to unexpected results.
+For instance, if you want to read a single line from a filehandle,
+assigning to a scalar value is fine:
+
+ $array[1] = <STDIN>;
+
+However, in list context, the line input operator returns all of the
+lines as a list. The first line goes into C<@array[1]> and the rest
+of the lines mysteriously disappear:
+
+ @array[1] = <STDIN>; # most likely not what you want
+
+Either the C<use warnings> pragma or the B<-w> flag will warn you when
+you use an array slice with a single index.
+
+=head2 How can I remove duplicate elements from a list or array?
+
+(contributed by brian d foy)
+
+Use a hash. When you think the words "unique" or "duplicated", think
+"hash keys".
+
+If you don't care about the order of the elements, you could just
+create the hash then extract the keys. It's not important how you
+create that hash: just that you use C<keys> to get the unique
+elements.
+
+ my %hash = map { $_, 1 } @array;
+ # or a hash slice: @hash{ @array } = ();
+ # or a foreach: $hash{$_} = 1 foreach ( @array );
+
+ my @unique = keys %hash;
+
+If you want to use a module, try the C<uniq> function from
+C<List::MoreUtils>. In list context it returns the unique elements,
+preserving their order in the list. In scalar context, it returns the
+number of unique elements.
+
+ use List::MoreUtils qw(uniq);
+
+ my @unique = uniq( 1, 2, 3, 4, 4, 5, 6, 5, 7 ); # 1,2,3,4,5,6,7
+ my $unique = uniq( 1, 2, 3, 4, 4, 5, 6, 5, 7 ); # 7
+
+You can also go through each element and skip the ones you've seen
+before. Use a hash to keep track. The first time the loop sees an
+element, that element has no key in C<%Seen>. The C<next> statement
+creates the key and immediately uses its value, which is C<undef>, so
+the loop continues to the C<push> and increments the value for that
+key. The next time the loop sees that same element, its key exists in
+the hash I<and> the value for that key is true (since it's not 0 or
+C<undef>), so the next skips that iteration and the loop goes to the
+next element.
+
+ my @unique = ();
+ my %seen = ();
+
+ foreach my $elem ( @array )
+ {
+ next if $seen{ $elem }++;
+ push @unique, $elem;
+ }
+
+You can write this more briefly using a grep, which does the
+same thing.
+
+ my %seen = ();
+ my @unique = grep { ! $seen{ $_ }++ } @array;
+
+=head2 How can I tell whether a certain element is contained in a list or array?
+
+(portions of this answer contributed by Anno Siegel and brian d foy)
+
+Hearing the word "in" is an I<in>dication that you probably should have
+used a hash, not a list or array, to store your data. Hashes are
+designed to answer this question quickly and efficiently. Arrays aren't.
+
+That being said, there are several ways to approach this. In Perl 5.10
+and later, you can use the smart match operator to check that an item is
+contained in an array or a hash:
+
+ use 5.010;
+
+ if( $item ~~ @array )
+ {
+ say "The array contains $item"
+ }
+
+ if( $item ~~ %hash )
+ {
+ say "The hash contains $item"
+ }
+
+With earlier versions of Perl, you have to do a bit more work. If you
+are going to make this query many times over arbitrary string values,
+the fastest way is probably to invert the original array and maintain a
+hash whose keys are the first array's values:
+
+ @blues = qw/azure cerulean teal turquoise lapis-lazuli/;
+ %is_blue = ();
+ for (@blues) { $is_blue{$_} = 1 }
+
+Now you can check whether C<$is_blue{$some_color}>. It might have
+been a good idea to keep the blues all in a hash in the first place.
+
+If the values are all small integers, you could use a simple indexed
+array. This kind of an array will take up less space:
+
+ @primes = (2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31);
+ @is_tiny_prime = ();
+ for (@primes) { $is_tiny_prime[$_] = 1 }
+ # or simply @istiny_prime[@primes] = (1) x @primes;
+
+Now you check whether $is_tiny_prime[$some_number].
+
+If the values in question are integers instead of strings, you can save
+quite a lot of space by using bit strings instead:
+
+ @articles = ( 1..10, 150..2000, 2017 );
+ undef $read;
+ for (@articles) { vec($read,$_,1) = 1 }
+
+Now check whether C<vec($read,$n,1)> is true for some C<$n>.
+
+These methods guarantee fast individual tests but require a re-organization
+of the original list or array. They only pay off if you have to test
+multiple values against the same array.
+
+If you are testing only once, the standard module C<List::Util> exports
+the function C<first> for this purpose. It works by stopping once it
+finds the element. It's written in C for speed, and its Perl equivalent
+looks like this subroutine:
+
+ sub first (&@) {
+ my $code = shift;
+ foreach (@_) {
+ return $_ if &{$code}();
+ }
+ undef;
+ }
+
+If speed is of little concern, the common idiom uses grep in scalar context
+(which returns the number of items that passed its condition) to traverse the
+entire list. This does have the benefit of telling you how many matches it
+found, though.
+
+ my $is_there = grep $_ eq $whatever, @array;
+
+If you want to actually extract the matching elements, simply use grep in
+list context.
+
+ my @matches = grep $_ eq $whatever, @array;
+
+=head2 How do I compute the difference of two arrays? How do I compute the intersection of two arrays?
+
+Use a hash. Here's code to do both and more. It assumes that each
+element is unique in a given array:
+
+ @union = @intersection = @difference = ();
+ %count = ();
+ foreach $element (@array1, @array2) { $count{$element}++ }
+ foreach $element (keys %count) {
+ push @union, $element;
+ push @{ $count{$element} > 1 ? \@intersection : \@difference }, $element;
+ }
+
+Note that this is the I<symmetric difference>, that is, all elements
+in either A or in B but not in both. Think of it as an xor operation.
+
+=head2 How do I test whether two arrays or hashes are equal?
+
+With Perl 5.10 and later, the smart match operator can give you the answer
+with the least amount of work:
+
+ use 5.010;
+
+ if( @array1 ~~ @array2 )
+ {
+ say "The arrays are the same";
+ }
+
+ if( %hash1 ~~ %hash2 ) # doesn't check values!
+ {
+ say "The hash keys are the same";
+ }
+
+The following code works for single-level arrays. It uses a
+stringwise comparison, and does not distinguish defined versus
+undefined empty strings. Modify if you have other needs.
+
+ $are_equal = compare_arrays(\@frogs, \@toads);
+
+ sub compare_arrays {
+ my ($first, $second) = @_;
+ no warnings; # silence spurious -w undef complaints
+ return 0 unless @$first == @$second;
+ for (my $i = 0; $i < @$first; $i++) {
+ return 0 if $first->[$i] ne $second->[$i];
+ }
+ return 1;
+ }
+
+For multilevel structures, you may wish to use an approach more
+like this one. It uses the CPAN module C<FreezeThaw>:
+
+ use FreezeThaw qw(cmpStr);
+ @a = @b = ( "this", "that", [ "more", "stuff" ] );
+
+ printf "a and b contain %s arrays\n",
+ cmpStr(\@a, \@b) == 0
+ ? "the same"
+ : "different";
+
+This approach also works for comparing hashes. Here we'll demonstrate
+two different answers:
+
+ use FreezeThaw qw(cmpStr cmpStrHard);
+
+ %a = %b = ( "this" => "that", "extra" => [ "more", "stuff" ] );
+ $a{EXTRA} = \%b;
+ $b{EXTRA} = \%a;
+
+ printf "a and b contain %s hashes\n",
+ cmpStr(\%a, \%b) == 0 ? "the same" : "different";
+
+ printf "a and b contain %s hashes\n",
+ cmpStrHard(\%a, \%b) == 0 ? "the same" : "different";
+
+
+The first reports that both those the hashes contain the same data,
+while the second reports that they do not. Which you prefer is left as
+an exercise to the reader.
+
+=head2 How do I find the first array element for which a condition is true?
+
+To find the first array element which satisfies a condition, you can
+use the C<first()> function in the C<List::Util> module, which comes
+with Perl 5.8. This example finds the first element that contains
+"Perl".
+
+ use List::Util qw(first);
+
+ my $element = first { /Perl/ } @array;
+
+If you cannot use C<List::Util>, you can make your own loop to do the
+same thing. Once you find the element, you stop the loop with last.
+
+ my $found;
+ foreach ( @array ) {
+ if( /Perl/ ) { $found = $_; last }
+ }
+
+If you want the array index, you can iterate through the indices
+and check the array element at each index until you find one
+that satisfies the condition.
+
+ my( $found, $index ) = ( undef, -1 );
+ for( $i = 0; $i < @array; $i++ ) {
+ if( $array[$i] =~ /Perl/ ) {
+ $found = $array[$i];
+ $index = $i;
+ last;
+ }
+ }
+
+=head2 How do I handle linked lists?
+
+In general, you usually don't need a linked list in Perl, since with
+regular arrays, you can push and pop or shift and unshift at either
+end, or you can use splice to add and/or remove arbitrary number of
+elements at arbitrary points. Both pop and shift are O(1)
+operations on Perl's dynamic arrays. In the absence of shifts and
+pops, push in general needs to reallocate on the order every log(N)
+times, and unshift will need to copy pointers each time.
+
+If you really, really wanted, you could use structures as described in
+L<perldsc> or L<perltoot> and do just what the algorithm book tells
+you to do. For example, imagine a list node like this:
+
+ $node = {
+ VALUE => 42,
+ LINK => undef,
+ };
+
+You could walk the list this way:
+
+ print "List: ";
+ for ($node = $head; $node; $node = $node->{LINK}) {
+ print $node->{VALUE}, " ";
+ }
+ print "\n";
+
+You could add to the list this way:
+
+ my ($head, $tail);
+ $tail = append($head, 1); # grow a new head
+ for $value ( 2 .. 10 ) {
+ $tail = append($tail, $value);
+ }
+
+ sub append {
+ my($list, $value) = @_;
+ my $node = { VALUE => $value };
+ if ($list) {
+ $node->{LINK} = $list->{LINK};
+ $list->{LINK} = $node;
+ }
+ else {
+ $_[0] = $node; # replace caller's version
+ }
+ return $node;
+ }
+
+But again, Perl's built-in are virtually always good enough.
+
+=head2 How do I handle circular lists?
+X<circular> X<array> X<Tie::Cycle> X<Array::Iterator::Circular>
+X<cycle> X<modulus>
+
+(contributed by brian d foy)
+
+If you want to cycle through an array endlessly, you can increment the
+index modulo the number of elements in the array:
+
+ my @array = qw( a b c );
+ my $i = 0;
+
+ while( 1 ) {
+ print $array[ $i++ % @array ], "\n";
+ last if $i > 20;
+ }
+
+You can also use C<Tie::Cycle> to use a scalar that always has the
+next element of the circular array:
+
+ use Tie::Cycle;
+
+ tie my $cycle, 'Tie::Cycle', [ qw( FFFFFF 000000 FFFF00 ) ];
+
+ print $cycle; # FFFFFF
+ print $cycle; # 000000
+ print $cycle; # FFFF00
+
+The C<Array::Iterator::Circular> creates an iterator object for
+circular arrays:
+
+ use Array::Iterator::Circular;
+
+ my $color_iterator = Array::Iterator::Circular->new(
+ qw(red green blue orange)
+ );
+
+ foreach ( 1 .. 20 ) {
+ print $color_iterator->next, "\n";
+ }
+
+=head2 How do I shuffle an array randomly?
+
+If you either have Perl 5.8.0 or later installed, or if you have
+Scalar-List-Utils 1.03 or later installed, you can say:
+
+ use List::Util 'shuffle';
+
+ @shuffled = shuffle(@list);
+
+If not, you can use a Fisher-Yates shuffle.
+
+ sub fisher_yates_shuffle {
+ my $deck = shift; # $deck is a reference to an array
+ return unless @$deck; # must not be empty!
+
+ my $i = @$deck;
+ while (--$i) {
+ my $j = int rand ($i+1);
+ @$deck[$i,$j] = @$deck[$j,$i];
+ }
+ }
+
+ # shuffle my mpeg collection
+ #
+ my @mpeg = <audio/*/*.mp3>;
+ fisher_yates_shuffle( \@mpeg ); # randomize @mpeg in place
+ print @mpeg;
+
+Note that the above implementation shuffles an array in place,
+unlike the C<List::Util::shuffle()> which takes a list and returns
+a new shuffled list.
+
+You've probably seen shuffling algorithms that work using splice,
+randomly picking another element to swap the current element with
+
+ srand;
+ @new = ();
+ @old = 1 .. 10; # just a demo
+ while (@old) {
+ push(@new, splice(@old, rand @old, 1));
+ }
+
+This is bad because splice is already O(N), and since you do it N
+times, you just invented a quadratic algorithm; that is, O(N**2).
+This does not scale, although Perl is so efficient that you probably
+won't notice this until you have rather largish arrays.
+
+=head2 How do I process/modify each element of an array?
+
+Use C<for>/C<foreach>:
+
+ for (@lines) {
+ s/foo/bar/; # change that word
+ tr/XZ/ZX/; # swap those letters
+ }
+
+Here's another; let's compute spherical volumes:
+
+ for (@volumes = @radii) { # @volumes has changed parts
+ $_ **= 3;
+ $_ *= (4/3) * 3.14159; # this will be constant folded
+ }
+
+which can also be done with C<map()> which is made to transform
+one list into another:
+
+ @volumes = map {$_ ** 3 * (4/3) * 3.14159} @radii;
+
+If you want to do the same thing to modify the values of the
+hash, you can use the C<values> function. As of Perl 5.6
+the values are not copied, so if you modify $orbit (in this
+case), you modify the value.
+
+ for $orbit ( values %orbits ) {
+ ($orbit **= 3) *= (4/3) * 3.14159;
+ }
+
+Prior to perl 5.6 C<values> returned copies of the values,
+so older perl code often contains constructions such as
+C<@orbits{keys %orbits}> instead of C<values %orbits> where
+the hash is to be modified.
+
+=head2 How do I select a random element from an array?
+
+Use the C<rand()> function (see L<perlfunc/rand>):
+
+ $index = rand @array;
+ $element = $array[$index];
+
+Or, simply:
+
+ my $element = $array[ rand @array ];
+
+=head2 How do I permute N elements of a list?
+X<List::Permuter> X<permute> X<Algorithm::Loops> X<Knuth>
+X<The Art of Computer Programming> X<Fischer-Krause>
+
+Use the C<List::Permutor> module on CPAN. If the list is actually an
+array, try the C<Algorithm::Permute> module (also on CPAN). It's
+written in XS code and is very efficient:
+
+ use Algorithm::Permute;
+
+ my @array = 'a'..'d';
+ my $p_iterator = Algorithm::Permute->new ( \@array );
+
+ while (my @perm = $p_iterator->next) {
+ print "next permutation: (@perm)\n";
+ }
+
+For even faster execution, you could do:
+
+ use Algorithm::Permute;
+
+ my @array = 'a'..'d';
+
+ Algorithm::Permute::permute {
+ print "next permutation: (@array)\n";
+ } @array;
+
+Here's a little program that generates all permutations of all the
+words on each line of input. The algorithm embodied in the
+C<permute()> function is discussed in Volume 4 (still unpublished) of
+Knuth's I<The Art of Computer Programming> and will work on any list:
+
+ #!/usr/bin/perl -n
+ # Fischer-Krause ordered permutation generator
+
+ sub permute (&@) {
+ my $code = shift;
+ my @idx = 0..$#_;
+ while ( $code->(@_[@idx]) ) {
+ my $p = $#idx;
+ --$p while $idx[$p-1] > $idx[$p];
+ my $q = $p or return;
+ push @idx, reverse splice @idx, $p;
+ ++$q while $idx[$p-1] > $idx[$q];
+ @idx[$p-1,$q]=@idx[$q,$p-1];
+ }
+ }
+
+ permute { print "@_\n" } split;
+
+The C<Algorithm::Loops> module also provides the C<NextPermute> and
+C<NextPermuteNum> functions which efficiently find all unique permutations
+of an array, even if it contains duplicate values, modifying it in-place:
+if its elements are in reverse-sorted order then the array is reversed,
+making it sorted, and it returns false; otherwise the next
+permutation is returned.
+
+C<NextPermute> uses string order and C<NextPermuteNum> numeric order, so
+you can enumerate all the permutations of C<0..9> like this:
+
+ use Algorithm::Loops qw(NextPermuteNum);
+
+ my @list= 0..9;
+ do { print "@list\n" } while NextPermuteNum @list;
+
+=head2 How do I sort an array by (anything)?
+
+Supply a comparison function to sort() (described in L<perlfunc/sort>):
+
+ @list = sort { $a <=> $b } @list;
+
+The default sort function is cmp, string comparison, which would
+sort C<(1, 2, 10)> into C<(1, 10, 2)>. C<< <=> >>, used above, is
+the numerical comparison operator.
+
+If you have a complicated function needed to pull out the part you
+want to sort on, then don't do it inside the sort function. Pull it
+out first, because the sort BLOCK can be called many times for the
+same element. Here's an example of how to pull out the first word
+after the first number on each item, and then sort those words
+case-insensitively.
+
+ @idx = ();
+ for (@data) {
+ ($item) = /\d+\s*(\S+)/;
+ push @idx, uc($item);
+ }
+ @sorted = @data[ sort { $idx[$a] cmp $idx[$b] } 0 .. $#idx ];
+
+which could also be written this way, using a trick
+that's come to be known as the Schwartzian Transform:
+
+ @sorted = map { $_->[0] }
+ sort { $a->[1] cmp $b->[1] }
+ map { [ $_, uc( (/\d+\s*(\S+)/)[0]) ] } @data;
+
+If you need to sort on several fields, the following paradigm is useful.
+
+ @sorted = sort {
+ field1($a) <=> field1($b) ||
+ field2($a) cmp field2($b) ||
+ field3($a) cmp field3($b)
+ } @data;
+
+This can be conveniently combined with precalculation of keys as given
+above.
+
+See the F<sort> article in the "Far More Than You Ever Wanted
+To Know" collection in http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz for
+more about this approach.
+
+See also the question later in L<perlfaq4> on sorting hashes.
+
+=head2 How do I manipulate arrays of bits?
+
+Use C<pack()> and C<unpack()>, or else C<vec()> and the bitwise
+operations.
+
+For example, you don't have to store individual bits in an array
+(which would mean that you're wasting a lot of space). To convert an
+array of bits to a string, use C<vec()> to set the right bits. This
+sets C<$vec> to have bit N set only if C<$ints[N]> was set:
+
+ @ints = (...); # array of bits, e.g. ( 1, 0, 0, 1, 1, 0 ... )
+ $vec = '';
+ foreach( 0 .. $#ints ) {
+ vec($vec,$_,1) = 1 if $ints[$_];
+ }
+
+The string C<$vec> only takes up as many bits as it needs. For
+instance, if you had 16 entries in C<@ints>, C<$vec> only needs two
+bytes to store them (not counting the scalar variable overhead).
+
+Here's how, given a vector in C<$vec>, you can get those bits into
+your C<@ints> array:
+
+ sub bitvec_to_list {
+ my $vec = shift;
+ my @ints;
+ # Find null-byte density then select best algorithm
+ if ($vec =~ tr/\0// / length $vec > 0.95) {
+ use integer;
+ my $i;
+
+ # This method is faster with mostly null-bytes
+ while($vec =~ /[^\0]/g ) {
+ $i = -9 + 8 * pos $vec;
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ }
+ }
+ else {
+ # This method is a fast general algorithm
+ use integer;
+ my $bits = unpack "b*", $vec;
+ push @ints, 0 if $bits =~ s/^(\d)// && $1;
+ push @ints, pos $bits while($bits =~ /1/g);
+ }
+
+ return \@ints;
+ }
+
+This method gets faster the more sparse the bit vector is.
+(Courtesy of Tim Bunce and Winfried Koenig.)
+
+You can make the while loop a lot shorter with this suggestion
+from Benjamin Goldberg:
+
+ while($vec =~ /[^\0]+/g ) {
+ push @ints, grep vec($vec, $_, 1), $-[0] * 8 .. $+[0] * 8;
+ }
+
+Or use the CPAN module C<Bit::Vector>:
+
+ $vector = Bit::Vector->new($num_of_bits);
+ $vector->Index_List_Store(@ints);
+ @ints = $vector->Index_List_Read();
+
+C<Bit::Vector> provides efficient methods for bit vector, sets of
+small integers and "big int" math.
+
+Here's a more extensive illustration using vec():
+
+ # vec demo
+ $vector = "\xff\x0f\xef\xfe";
+ print "Ilya's string \\xff\\x0f\\xef\\xfe represents the number ",
+ unpack("N", $vector), "\n";
+ $is_set = vec($vector, 23, 1);
+ print "Its 23rd bit is ", $is_set ? "set" : "clear", ".\n";
+ pvec($vector);
+
+ set_vec(1,1,1);
+ set_vec(3,1,1);
+ set_vec(23,1,1);
+
+ set_vec(3,1,3);
+ set_vec(3,2,3);
+ set_vec(3,4,3);
+ set_vec(3,4,7);
+ set_vec(3,8,3);
+ set_vec(3,8,7);
+
+ set_vec(0,32,17);
+ set_vec(1,32,17);
+
+ sub set_vec {
+ my ($offset, $width, $value) = @_;
+ my $vector = '';
+ vec($vector, $offset, $width) = $value;
+ print "offset=$offset width=$width value=$value\n";
+ pvec($vector);
+ }
+
+ sub pvec {
+ my $vector = shift;
+ my $bits = unpack("b*", $vector);
+ my $i = 0;
+ my $BASE = 8;
+
+ print "vector length in bytes: ", length($vector), "\n";
+ @bytes = unpack("A8" x length($vector), $bits);
+ print "bits are: @bytes\n\n";
+ }
+
+=head2 Why does defined() return true on empty arrays and hashes?
+
+The short story is that you should probably only use defined on scalars or
+functions, not on aggregates (arrays and hashes). See L<perlfunc/defined>
+in the 5.004 release or later of Perl for more detail.
+
+=head1 Data: Hashes (Associative Arrays)
+
+=head2 How do I process an entire hash?
+
+(contributed by brian d foy)
+
+There are a couple of ways that you can process an entire hash. You
+can get a list of keys, then go through each key, or grab a one
+key-value pair at a time.
+
+To go through all of the keys, use the C<keys> function. This extracts
+all of the keys of the hash and gives them back to you as a list. You
+can then get the value through the particular key you're processing:
+
+ foreach my $key ( keys %hash ) {
+ my $value = $hash{$key}
+ ...
+ }
+
+Once you have the list of keys, you can process that list before you
+process the hash elements. For instance, you can sort the keys so you
+can process them in lexical order:
+
+ foreach my $key ( sort keys %hash ) {
+ my $value = $hash{$key}
+ ...
+ }
+
+Or, you might want to only process some of the items. If you only want
+to deal with the keys that start with C<text:>, you can select just
+those using C<grep>:
+
+ foreach my $key ( grep /^text:/, keys %hash ) {
+ my $value = $hash{$key}
+ ...
+ }
+
+If the hash is very large, you might not want to create a long list of
+keys. To save some memory, you can grab one key-value pair at a time using
+C<each()>, which returns a pair you haven't seen yet:
+
+ while( my( $key, $value ) = each( %hash ) ) {
+ ...
+ }
+
+The C<each> operator returns the pairs in apparently random order, so if
+ordering matters to you, you'll have to stick with the C<keys> method.
+
+The C<each()> operator can be a bit tricky though. You can't add or
+delete keys of the hash while you're using it without possibly
+skipping or re-processing some pairs after Perl internally rehashes
+all of the elements. Additionally, a hash has only one iterator, so if
+you use C<keys>, C<values>, or C<each> on the same hash, you can reset
+the iterator and mess up your processing. See the C<each> entry in
+L<perlfunc> for more details.
+
+=head2 How do I merge two hashes?
+X<hash> X<merge> X<slice, hash>
+
+(contributed by brian d foy)
+
+Before you decide to merge two hashes, you have to decide what to do
+if both hashes contain keys that are the same and if you want to leave
+the original hashes as they were.
+
+If you want to preserve the original hashes, copy one hash (C<%hash1>)
+to a new hash (C<%new_hash>), then add the keys from the other hash
+(C<%hash2> to the new hash. Checking that the key already exists in
+C<%new_hash> gives you a chance to decide what to do with the
+duplicates:
+
+ my %new_hash = %hash1; # make a copy; leave %hash1 alone
+
+ foreach my $key2 ( keys %hash2 )
+ {
+ if( exists $new_hash{$key2} )
+ {
+ warn "Key [$key2] is in both hashes!";
+ # handle the duplicate (perhaps only warning)
+ ...
+ next;
+ }
+ else
+ {
+ $new_hash{$key2} = $hash2{$key2};
+ }
+ }
+
+If you don't want to create a new hash, you can still use this looping
+technique; just change the C<%new_hash> to C<%hash1>.
+
+ foreach my $key2 ( keys %hash2 )
+ {
+ if( exists $hash1{$key2} )
+ {
+ warn "Key [$key2] is in both hashes!";
+ # handle the duplicate (perhaps only warning)
+ ...
+ next;
+ }
+ else
+ {
+ $hash1{$key2} = $hash2{$key2};
+ }
+ }
+
+If you don't care that one hash overwrites keys and values from the other, you
+could just use a hash slice to add one hash to another. In this case, values
+from C<%hash2> replace values from C<%hash1> when they have keys in common:
+
+ @hash1{ keys %hash2 } = values %hash2;
+
+=head2 What happens if I add or remove keys from a hash while iterating over it?
+
+(contributed by brian d foy)
+
+The easy answer is "Don't do that!"
+
+If you iterate through the hash with each(), you can delete the key
+most recently returned without worrying about it. If you delete or add
+other keys, the iterator may skip or double up on them since perl
+may rearrange the hash table. See the
+entry for C<each()> in L<perlfunc>.
+
+=head2 How do I look up a hash element by value?
+
+Create a reverse hash:
+
+ %by_value = reverse %by_key;
+ $key = $by_value{$value};
+
+That's not particularly efficient. It would be more space-efficient
+to use:
+
+ while (($key, $value) = each %by_key) {
+ $by_value{$value} = $key;
+ }
+
+If your hash could have repeated values, the methods above will only find
+one of the associated keys. This may or may not worry you. If it does
+worry you, you can always reverse the hash into a hash of arrays instead:
+
+ while (($key, $value) = each %by_key) {
+ push @{$key_list_by_value{$value}}, $key;
+ }
+
+=head2 How can I know how many entries are in a hash?
+
+(contributed by brian d foy)
+
+This is very similar to "How do I process an entire hash?", also in
+L<perlfaq4>, but a bit simpler in the common cases.
+
+You can use the C<keys()> built-in function in scalar context to find out
+have many entries you have in a hash:
+
+ my $key_count = keys %hash; # must be scalar context!
+
+If you want to find out how many entries have a defined value, that's
+a bit different. You have to check each value. A C<grep> is handy:
+
+ my $defined_value_count = grep { defined } values %hash;
+
+You can use that same structure to count the entries any way that
+you like. If you want the count of the keys with vowels in them,
+you just test for that instead:
+
+ my $vowel_count = grep { /[aeiou]/ } keys %hash;
+
+The C<grep> in scalar context returns the count. If you want the list
+of matching items, just use it in list context instead:
+
+ my @defined_values = grep { defined } values %hash;
+
+The C<keys()> function also resets the iterator, which means that you may
+see strange results if you use this between uses of other hash operators
+such as C<each()>.
+
+=head2 How do I sort a hash (optionally by value instead of key)?
+
+(contributed by brian d foy)
+
+To sort a hash, start with the keys. In this example, we give the list of
+keys to the sort function which then compares them ASCIIbetically (which
+might be affected by your locale settings). The output list has the keys
+in ASCIIbetical order. Once we have the keys, we can go through them to
+create a report which lists the keys in ASCIIbetical order.
+
+ my @keys = sort { $a cmp $b } keys %hash;
+
+ foreach my $key ( @keys )
+ {
+ printf "%-20s %6d\n", $key, $hash{$key};
+ }
+
+We could get more fancy in the C<sort()> block though. Instead of
+comparing the keys, we can compute a value with them and use that
+value as the comparison.
+
+For instance, to make our report order case-insensitive, we use
+the C<\L> sequence in a double-quoted string to make everything
+lowercase. The C<sort()> block then compares the lowercased
+values to determine in which order to put the keys.
+
+ my @keys = sort { "\L$a" cmp "\L$b" } keys %hash;
+
+Note: if the computation is expensive or the hash has many elements,
+you may want to look at the Schwartzian Transform to cache the
+computation results.
+
+If we want to sort by the hash value instead, we use the hash key
+to look it up. We still get out a list of keys, but this time they
+are ordered by their value.
+
+ my @keys = sort { $hash{$a} <=> $hash{$b} } keys %hash;
+
+From there we can get more complex. If the hash values are the same,
+we can provide a secondary sort on the hash key.
+
+ my @keys = sort {
+ $hash{$a} <=> $hash{$b}
+ or
+ "\L$a" cmp "\L$b"
+ } keys %hash;
+
+=head2 How can I always keep my hash sorted?
+X<hash tie sort DB_File Tie::IxHash>
+
+You can look into using the C<DB_File> module and C<tie()> using the
+C<$DB_BTREE> hash bindings as documented in L<DB_File/"In Memory
+Databases">. The C<Tie::IxHash> module from CPAN might also be
+instructive. Although this does keep your hash sorted, you might not
+like the slow down you suffer from the tie interface. Are you sure you
+need to do this? :)
+
+=head2 What's the difference between "delete" and "undef" with hashes?
+
+Hashes contain pairs of scalars: the first is the key, the
+second is the value. The key will be coerced to a string,
+although the value can be any kind of scalar: string,
+number, or reference. If a key C<$key> is present in
+%hash, C<exists($hash{$key})> will return true. The value
+for a given key can be C<undef>, in which case
+C<$hash{$key}> will be C<undef> while C<exists $hash{$key}>
+will return true. This corresponds to (C<$key>, C<undef>)
+being in the hash.
+
+Pictures help... Here's the C<%hash> table:
+
+ keys values
+ +------+------+
+ | a | 3 |
+ | x | 7 |
+ | d | 0 |
+ | e | 2 |
+ +------+------+
+
+And these conditions hold
+
+ $hash{'a'} is true
+ $hash{'d'} is false
+ defined $hash{'d'} is true
+ defined $hash{'a'} is true
+ exists $hash{'a'} is true (Perl 5 only)
+ grep ($_ eq 'a', keys %hash) is true
+
+If you now say
+
+ undef $hash{'a'}
+
+your table now reads:
+
+
+ keys values
+ +------+------+
+ | a | undef|
+ | x | 7 |
+ | d | 0 |
+ | e | 2 |
+ +------+------+
+
+and these conditions now hold; changes in caps:
+
+ $hash{'a'} is FALSE
+ $hash{'d'} is false
+ defined $hash{'d'} is true
+ defined $hash{'a'} is FALSE
+ exists $hash{'a'} is true (Perl 5 only)
+ grep ($_ eq 'a', keys %hash) is true
+
+Notice the last two: you have an undef value, but a defined key!
+
+Now, consider this:
+
+ delete $hash{'a'}
+
+your table now reads:
+
+ keys values
+ +------+------+
+ | x | 7 |
+ | d | 0 |
+ | e | 2 |
+ +------+------+
+
+and these conditions now hold; changes in caps:
+
+ $hash{'a'} is false
+ $hash{'d'} is false
+ defined $hash{'d'} is true
+ defined $hash{'a'} is false
+ exists $hash{'a'} is FALSE (Perl 5 only)
+ grep ($_ eq 'a', keys %hash) is FALSE
+
+See, the whole entry is gone!
+
+=head2 Why don't my tied hashes make the defined/exists distinction?
+
+This depends on the tied hash's implementation of EXISTS().
+For example, there isn't the concept of undef with hashes
+that are tied to DBM* files. It also means that exists() and
+defined() do the same thing with a DBM* file, and what they
+end up doing is not what they do with ordinary hashes.
+
+=head2 How do I reset an each() operation part-way through?
+
+(contributed by brian d foy)
+
+You can use the C<keys> or C<values> functions to reset C<each>. To
+simply reset the iterator used by C<each> without doing anything else,
+use one of them in void context:
+
+ keys %hash; # resets iterator, nothing else.
+ values %hash; # resets iterator, nothing else.
+
+See the documentation for C<each> in L<perlfunc>.
+
+=head2 How can I get the unique keys from two hashes?
+
+First you extract the keys from the hashes into lists, then solve
+the "removing duplicates" problem described above. For example:
+
+ %seen = ();
+ for $element (keys(%foo), keys(%bar)) {
+ $seen{$element}++;
+ }
+ @uniq = keys %seen;
+
+Or more succinctly:
+
+ @uniq = keys %{{%foo,%bar}};
+
+Or if you really want to save space:
+
+ %seen = ();
+ while (defined ($key = each %foo)) {
+ $seen{$key}++;
+ }
+ while (defined ($key = each %bar)) {
+ $seen{$key}++;
+ }
+ @uniq = keys %seen;
+
+=head2 How can I store a multidimensional array in a DBM file?
+
+Either stringify the structure yourself (no fun), or else
+get the MLDBM (which uses Data::Dumper) module from CPAN and layer
+it on top of either DB_File or GDBM_File.
+
+=head2 How can I make my hash remember the order I put elements into it?
+
+Use the C<Tie::IxHash> from CPAN.
+
+ use Tie::IxHash;
+
+ tie my %myhash, 'Tie::IxHash';
+
+ for (my $i=0; $i<20; $i++) {
+ $myhash{$i} = 2*$i;
+ }
+
+ my @keys = keys %myhash;
+ # @keys = (0,1,2,3,...)
+
+=head2 Why does passing a subroutine an undefined element in a hash create it?
+
+(contributed by brian d foy)
+
+Are you using a really old version of Perl?
+
+Normally, accessing a hash key's value for a nonexistent key will
+I<not> create the key.
+
+ my %hash = ();
+ my $value = $hash{ 'foo' };
+ print "This won't print\n" if exists $hash{ 'foo' };
+
+Passing C<$hash{ 'foo' }> to a subroutine used to be a special case, though.
+Since you could assign directly to C<$_[0]>, Perl had to be ready to
+make that assignment so it created the hash key ahead of time:
+
+ my_sub( $hash{ 'foo' } );
+ print "This will print before 5.004\n" if exists $hash{ 'foo' };
+
+ sub my_sub {
+ # $_[0] = 'bar'; # create hash key in case you do this
+ 1;
+ }
+
+Since Perl 5.004, however, this situation is a special case and Perl
+creates the hash key only when you make the assignment:
+
+ my_sub( $hash{ 'foo' } );
+ print "This will print, even after 5.004\n" if exists $hash{ 'foo' };
+
+ sub my_sub {
+ $_[0] = 'bar';
+ }
+
+However, if you want the old behavior (and think carefully about that
+because it's a weird side effect), you can pass a hash slice instead.
+Perl 5.004 didn't make this a special case:
+
+ my_sub( @hash{ qw/foo/ } );
+
+=head2 How can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays?
+
+Usually a hash ref, perhaps like this:
+
+ $record = {
+ NAME => "Jason",
+ EMPNO => 132,
+ TITLE => "deputy peon",
+ AGE => 23,
+ SALARY => 37_000,
+ PALS => [ "Norbert", "Rhys", "Phineas"],
+ };
+
+References are documented in L<perlref> and the upcoming L<perlreftut>.
+Examples of complex data structures are given in L<perldsc> and
+L<perllol>. Examples of structures and object-oriented classes are
+in L<perltoot>.
+
+=head2 How can I use a reference as a hash key?
+
+(contributed by brian d foy and Ben Morrow)
+
+Hash keys are strings, so you can't really use a reference as the key.
+When you try to do that, perl turns the reference into its stringified
+form (for instance, C<HASH(0xDEADBEEF)>). From there you can't get
+back the reference from the stringified form, at least without doing
+some extra work on your own.
+
+Remember that the entry in the hash will still be there even if
+the referenced variable goes out of scope, and that it is entirely
+possible for Perl to subsequently allocate a different variable at
+the same address. This will mean a new variable might accidentally
+be associated with the value for an old.
+
+If you have Perl 5.10 or later, and you just want to store a value
+against the reference for lookup later, you can use the core
+Hash::Util::Fieldhash module. This will also handle renaming the
+keys if you use multiple threads (which causes all variables to be
+reallocated at new addresses, changing their stringification), and
+garbage-collecting the entries when the referenced variable goes out
+of scope.
+
+If you actually need to be able to get a real reference back from
+each hash entry, you can use the Tie::RefHash module, which does the
+required work for you.
+
+=head1 Data: Misc
+
+=head2 How do I handle binary data correctly?
+
+Perl is binary clean, so it can handle binary data just fine.
+On Windows or DOS, however, you have to use C<binmode> for binary
+files to avoid conversions for line endings. In general, you should
+use C<binmode> any time you want to work with binary data.
+
+Also see L<perlfunc/"binmode"> or L<perlopentut>.
+
+If you're concerned about 8-bit textual data then see L<perllocale>.
+If you want to deal with multibyte characters, however, there are
+some gotchas. See the section on Regular Expressions.
+
+=head2 How do I determine whether a scalar is a number/whole/integer/float?
+
+Assuming that you don't care about IEEE notations like "NaN" or
+"Infinity", you probably just want to use a regular expression.
+
+ if (/\D/) { print "has nondigits\n" }
+ if (/^\d+$/) { print "is a whole number\n" }
+ if (/^-?\d+$/) { print "is an integer\n" }
+ if (/^[+-]?\d+$/) { print "is a +/- integer\n" }
+ if (/^-?\d+\.?\d*$/) { print "is a real number\n" }
+ if (/^-?(?:\d+(?:\.\d*)?|\.\d+)$/) { print "is a decimal number\n" }
+ if (/^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/)
+ { print "a C float\n" }
+
+There are also some commonly used modules for the task.
+L<Scalar::Util> (distributed with 5.8) provides access to perl's
+internal function C<looks_like_number> for determining whether a
+variable looks like a number. L<Data::Types> exports functions that
+validate data types using both the above and other regular
+expressions. Thirdly, there is C<Regexp::Common> which has regular
+expressions to match various types of numbers. Those three modules are
+available from the CPAN.
+
+If you're on a POSIX system, Perl supports the C<POSIX::strtod>
+function. Its semantics are somewhat cumbersome, so here's a
+C<getnum> wrapper function for more convenient access. This function
+takes a string and returns the number it found, or C<undef> for input
+that isn't a C float. The C<is_numeric> function is a front end to
+C<getnum> if you just want to say, "Is this a float?"
+
+ sub getnum {
+ use POSIX qw(strtod);
+ my $str = shift;
+ $str =~ s/^\s+//;
+ $str =~ s/\s+$//;
+ $! = 0;
+ my($num, $unparsed) = strtod($str);
+ if (($str eq '') || ($unparsed != 0) || $!) {
+ return undef;
+ }
+ else {
+ return $num;
+ }
+ }
+
+ sub is_numeric { defined getnum($_[0]) }
+
+Or you could check out the L<String::Scanf> module on the CPAN
+instead. The C<POSIX> module (part of the standard Perl distribution)
+provides the C<strtod> and C<strtol> for converting strings to double
+and longs, respectively.
+
+=head2 How do I keep persistent data across program calls?
+
+For some specific applications, you can use one of the DBM modules.
+See L<AnyDBM_File>. More generically, you should consult the C<FreezeThaw>
+or C<Storable> modules from CPAN. Starting from Perl 5.8 C<Storable> is part
+of the standard distribution. Here's one example using C<Storable>'s C<store>
+and C<retrieve> functions:
+
+ use Storable;
+ store(\%hash, "filename");
+
+ # later on...
+ $href = retrieve("filename"); # by ref
+ %hash = %{ retrieve("filename") }; # direct to hash
+
+=head2 How do I print out or copy a recursive data structure?
+
+The C<Data::Dumper> module on CPAN (or the 5.005 release of Perl) is great
+for printing out data structures. The C<Storable> module on CPAN (or the
+5.8 release of Perl), provides a function called C<dclone> that recursively
+copies its argument.
+
+ use Storable qw(dclone);
+ $r2 = dclone($r1);
+
+Where C<$r1> can be a reference to any kind of data structure you'd like.
+It will be deeply copied. Because C<dclone> takes and returns references,
+you'd have to add extra punctuation if you had a hash of arrays that
+you wanted to copy.
+
+ %newhash = %{ dclone(\%oldhash) };
+
+=head2 How do I define methods for every class/object?
+
+(contributed by Ben Morrow)
+
+You can use the C<UNIVERSAL> class (see L<UNIVERSAL>). However, please
+be very careful to consider the consequences of doing this: adding
+methods to every object is very likely to have unintended
+consequences. If possible, it would be better to have all your object
+inherit from some common base class, or to use an object system like
+Moose that supports roles.
+
+=head2 How do I verify a credit card checksum?
+
+Get the C<Business::CreditCard> module from CPAN.
+
+=head2 How do I pack arrays of doubles or floats for XS code?
+
+The arrays.h/arrays.c code in the C<PGPLOT> module on CPAN does just this.
+If you're doing a lot of float or double processing, consider using
+the C<PDL> module from CPAN instead--it makes number-crunching easy.
+
+See L<http://search.cpan.org/dist/PGPLOT> for the code.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq5.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq5.pod
new file mode 100644
index 00000000000..bd969f4393f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq5.pod
@@ -0,0 +1,1545 @@
+=head1 NAME
+
+perlfaq5 - Files and Formats
+
+=head1 DESCRIPTION
+
+This section deals with I/O and the "f" issues: filehandles, flushing,
+formats, and footers.
+
+=head2 How do I flush/unbuffer an output filehandle? Why must I do this?
+X<flush> X<buffer> X<unbuffer> X<autoflush>
+
+(contributed by brian d foy)
+
+You might like to read Mark Jason Dominus's "Suffering From Buffering"
+at http://perl.plover.com/FAQs/Buffering.html .
+
+Perl normally buffers output so it doesn't make a system call for every
+bit of output. By saving up output, it makes fewer expensive system calls.
+For instance, in this little bit of code, you want to print a dot to the
+screen for every line you process to watch the progress of your program.
+Instead of seeing a dot for every line, Perl buffers the output and you
+have a long wait before you see a row of 50 dots all at once:
+
+ # long wait, then row of dots all at once
+ while( <> ) {
+ print ".";
+ print "\n" unless ++$count % 50;
+
+ #... expensive line processing operations
+ }
+
+To get around this, you have to unbuffer the output filehandle, in this
+case, C<STDOUT>. You can set the special variable C<$|> to a true value
+(mnemonic: making your filehandles "piping hot"):
+
+ $|++;
+
+ # dot shown immediately
+ while( <> ) {
+ print ".";
+ print "\n" unless ++$count % 50;
+
+ #... expensive line processing operations
+ }
+
+The C<$|> is one of the per-filehandle special variables, so each
+filehandle has its own copy of its value. If you want to merge
+standard output and standard error for instance, you have to unbuffer
+each (although STDERR might be unbuffered by default):
+
+ {
+ my $previous_default = select(STDOUT); # save previous default
+ $|++; # autoflush STDOUT
+ select(STDERR);
+ $|++; # autoflush STDERR, to be sure
+ select($previous_default); # restore previous default
+ }
+
+ # now should alternate . and +
+ while( 1 )
+ {
+ sleep 1;
+ print STDOUT ".";
+ print STDERR "+";
+ print STDOUT "\n" unless ++$count % 25;
+ }
+
+Besides the C<$|> special variable, you can use C<binmode> to give
+your filehandle a C<:unix> layer, which is unbuffered:
+
+ binmode( STDOUT, ":unix" );
+
+ while( 1 ) {
+ sleep 1;
+ print ".";
+ print "\n" unless ++$count % 50;
+ }
+
+For more information on output layers, see the entries for C<binmode>
+and C<open> in L<perlfunc>, and the C<PerlIO> module documentation.
+
+If you are using C<IO::Handle> or one of its subclasses, you can
+call the C<autoflush> method to change the settings of the
+filehandle:
+
+ use IO::Handle;
+ open my( $io_fh ), ">", "output.txt";
+ $io_fh->autoflush(1);
+
+The C<IO::Handle> objects also have a C<flush> method. You can flush
+the buffer any time you want without auto-buffering
+
+ $io_fh->flush;
+
+=head2 How do I change, delete, or insert a line in a file, or append to the beginning of a file?
+X<file, editing>
+
+(contributed by brian d foy)
+
+The basic idea of inserting, changing, or deleting a line from a text
+file involves reading and printing the file to the point you want to
+make the change, making the change, then reading and printing the rest
+of the file. Perl doesn't provide random access to lines (especially
+since the record input separator, C<$/>, is mutable), although modules
+such as C<Tie::File> can fake it.
+
+A Perl program to do these tasks takes the basic form of opening a
+file, printing its lines, then closing the file:
+
+ open my $in, '<', $file or die "Can't read old file: $!";
+ open my $out, '>', "$file.new" or die "Can't write new file: $!";
+
+ while( <$in> )
+ {
+ print $out $_;
+ }
+
+ close $out;
+
+Within that basic form, add the parts that you need to insert, change,
+or delete lines.
+
+To prepend lines to the beginning, print those lines before you enter
+the loop that prints the existing lines.
+
+ open my $in, '<', $file or die "Can't read old file: $!";
+ open my $out, '>', "$file.new" or die "Can't write new file: $!";
+
+ print $out "# Add this line to the top\n"; # <--- HERE'S THE MAGIC
+
+ while( <$in> )
+ {
+ print $out $_;
+ }
+
+ close $out;
+
+To change existing lines, insert the code to modify the lines inside
+the C<while> loop. In this case, the code finds all lowercased
+versions of "perl" and uppercases them. The happens for every line, so
+be sure that you're supposed to do that on every line!
+
+ open my $in, '<', $file or die "Can't read old file: $!";
+ open my $out, '>', "$file.new" or die "Can't write new file: $!";
+
+ print $out "# Add this line to the top\n";
+
+ while( <$in> )
+ {
+ s/\b(perl)\b/Perl/g;
+ print $out $_;
+ }
+
+ close $out;
+
+To change only a particular line, the input line number, C<$.>, is
+useful. First read and print the lines up to the one you want to
+change. Next, read the single line you want to change, change it, and
+print it. After that, read the rest of the lines and print those:
+
+ while( <$in> ) # print the lines before the change
+ {
+ print $out $_;
+ last if $. == 4; # line number before change
+ }
+
+ my $line = <$in>;
+ $line =~ s/\b(perl)\b/Perl/g;
+ print $out $line;
+
+ while( <$in> ) # print the rest of the lines
+ {
+ print $out $_;
+ }
+
+To skip lines, use the looping controls. The C<next> in this example
+skips comment lines, and the C<last> stops all processing once it
+encounters either C<__END__> or C<__DATA__>.
+
+ while( <$in> )
+ {
+ next if /^\s+#/; # skip comment lines
+ last if /^__(END|DATA)__$/; # stop at end of code marker
+ print $out $_;
+ }
+
+Do the same sort of thing to delete a particular line by using C<next>
+to skip the lines you don't want to show up in the output. This
+example skips every fifth line:
+
+ while( <$in> )
+ {
+ next unless $. % 5;
+ print $out $_;
+ }
+
+If, for some odd reason, you really want to see the whole file at once
+rather than processing line-by-line, you can slurp it in (as long as
+you can fit the whole thing in memory!):
+
+ open my $in, '<', $file or die "Can't read old file: $!"
+ open my $out, '>', "$file.new" or die "Can't write new file: $!";
+
+ my @lines = do { local $/; <$in> }; # slurp!
+
+ # do your magic here
+
+ print $out @lines;
+
+Modules such as C<File::Slurp> and C<Tie::File> can help with that
+too. If you can, however, avoid reading the entire file at once. Perl
+won't give that memory back to the operating system until the process
+finishes.
+
+You can also use Perl one-liners to modify a file in-place. The
+following changes all 'Fred' to 'Barney' in F<inFile.txt>, overwriting
+the file with the new contents. With the C<-p> switch, Perl wraps a
+C<while> loop around the code you specify with C<-e>, and C<-i> turns
+on in-place editing. The current line is in C<$_>. With C<-p>, Perl
+automatically prints the value of C<$_> at the end of the loop. See
+L<perlrun> for more details.
+
+ perl -pi -e 's/Fred/Barney/' inFile.txt
+
+To make a backup of C<inFile.txt>, give C<-i> a file extension to add:
+
+ perl -pi.bak -e 's/Fred/Barney/' inFile.txt
+
+To change only the fifth line, you can add a test checking C<$.>, the
+input line number, then only perform the operation when the test
+passes:
+
+ perl -pi -e 's/Fred/Barney/ if $. == 5' inFile.txt
+
+To add lines before a certain line, you can add a line (or lines!)
+before Perl prints C<$_>:
+
+ perl -pi -e 'print "Put before third line\n" if $. == 3' inFile.txt
+
+You can even add a line to the beginning of a file, since the current
+line prints at the end of the loop:
+
+ perl -pi -e 'print "Put before first line\n" if $. == 1' inFile.txt
+
+To insert a line after one already in the file, use the C<-n> switch.
+It's just like C<-p> except that it doesn't print C<$_> at the end of
+the loop, so you have to do that yourself. In this case, print C<$_>
+first, then print the line that you want to add.
+
+ perl -ni -e 'print; print "Put after fifth line\n" if $. == 5' inFile.txt
+
+To delete lines, only print the ones that you want.
+
+ perl -ni -e 'print unless /d/' inFile.txt
+
+ ... or ...
+
+ perl -pi -e 'next unless /d/' inFile.txt
+
+=head2 How do I count the number of lines in a file?
+X<file, counting lines> X<lines> X<line>
+
+(contributed by brian d foy)
+
+Conceptually, the easiest way to count the lines in a file is to
+simply read them and count them:
+
+ my $count = 0;
+ while( <$fh> ) { $count++; }
+
+You don't really have to count them yourself, though, since Perl
+already does that with the C<$.> variable, which is the current line
+number from the last filehandle read:
+
+ 1 while( <$fh> );
+ my $count = $.;
+
+If you want to use C<$.>, you can reduce it to a simple one-liner,
+like one of these:
+
+ % perl -lne '} print $.; {' file
+
+ % perl -lne 'END { print $. }' file
+
+Those can be rather inefficient though. If they aren't fast enough for
+you, you might just read chunks of data and count the number of
+newlines:
+
+ my $lines = 0;
+ open my($fh), '<:raw', $filename or die "Can't open $filename: $!";
+ while( sysread $fh, $buffer, 4096 ) {
+ $lines += ( $buffer =~ tr/\n// );
+ }
+ close FILE;
+
+However, that doesn't work if the line ending isn't a newline. You
+might change that C<tr///> to a C<s///> so you can count the number of
+times the input record separator, C<$/>, shows up:
+
+ my $lines = 0;
+ open my($fh), '<:raw', $filename or die "Can't open $filename: $!";
+ while( sysread $fh, $buffer, 4096 ) {
+ $lines += ( $buffer =~ s|$/||g; );
+ }
+ close FILE;
+
+If you don't mind shelling out, the C<wc> command is usually the
+fastest, even with the extra interprocess overhead. Ensure that you
+have an untainted filename though:
+
+ #!perl -T
+
+ $ENV{PATH} = undef;
+
+ my $lines;
+ if( $filename =~ /^([0-9a-z_.]+)\z/ ) {
+ $lines = `/usr/bin/wc -l $1`
+ chomp $lines;
+ }
+
+=head2 How do I delete the last N lines from a file?
+X<lines> X<file>
+
+(contributed by brian d foy)
+
+The easiest conceptual solution is to count the lines in the
+file then start at the beginning and print the number of lines
+(minus the last N) to a new file.
+
+Most often, the real question is how you can delete the last N lines
+without making more than one pass over the file, or how to do it
+without a lot of copying. The easy concept is the hard reality when
+you might have millions of lines in your file.
+
+One trick is to use C<File::ReadBackwards>, which starts at the end of
+the file. That module provides an object that wraps the real filehandle
+to make it easy for you to move around the file. Once you get to the
+spot you need, you can get the actual filehandle and work with it as
+normal. In this case, you get the file position at the end of the last
+line you want to keep and truncate the file to that point:
+
+ use File::ReadBackwards;
+
+ my $filename = 'test.txt';
+ my $Lines_to_truncate = 2;
+
+ my $bw = File::ReadBackwards->new( $filename )
+ or die "Could not read backwards in [$filename]: $!";
+
+ my $lines_from_end = 0;
+ until( $bw->eof or $lines_from_end == $Lines_to_truncate )
+ {
+ print "Got: ", $bw->readline;
+ $lines_from_end++;
+ }
+
+ truncate( $filename, $bw->tell );
+
+The C<File::ReadBackwards> module also has the advantage of setting
+the input record separator to a regular expression.
+
+You can also use the C<Tie::File> module which lets you access
+the lines through a tied array. You can use normal array operations
+to modify your file, including setting the last index and using
+C<splice>.
+
+=head2 How can I use Perl's C<-i> option from within a program?
+X<-i> X<in-place>
+
+C<-i> sets the value of Perl's C<$^I> variable, which in turn affects
+the behavior of C<< <> >>; see L<perlrun> for more details. By
+modifying the appropriate variables directly, you can get the same
+behavior within a larger program. For example:
+
+ # ...
+ {
+ local($^I, @ARGV) = ('.orig', glob("*.c"));
+ while (<>) {
+ if ($. == 1) {
+ print "This line should appear at the top of each file\n";
+ }
+ s/\b(p)earl\b/${1}erl/i; # Correct typos, preserving case
+ print;
+ close ARGV if eof; # Reset $.
+ }
+ }
+ # $^I and @ARGV return to their old values here
+
+This block modifies all the C<.c> files in the current directory,
+leaving a backup of the original data from each file in a new
+C<.c.orig> file.
+
+=head2 How can I copy a file?
+X<copy> X<file, copy> X<File::Copy>
+
+(contributed by brian d foy)
+
+Use the C<File::Copy> module. It comes with Perl and can do a
+true copy across file systems, and it does its magic in
+a portable fashion.
+
+ use File::Copy;
+
+ copy( $original, $new_copy ) or die "Copy failed: $!";
+
+If you can't use C<File::Copy>, you'll have to do the work yourself:
+open the original file, open the destination file, then print
+to the destination file as you read the original. You also have to
+remember to copy the permissions, owner, and group to the new file.
+
+=head2 How do I make a temporary file name?
+X<file, temporary>
+
+If you don't need to know the name of the file, you can use C<open()>
+with C<undef> in place of the file name. In Perl 5.8 or later, the
+C<open()> function creates an anonymous temporary file:
+
+ open my $tmp, '+>', undef or die $!;
+
+Otherwise, you can use the File::Temp module.
+
+ use File::Temp qw/ tempfile tempdir /;
+
+ my $dir = tempdir( CLEANUP => 1 );
+ ($fh, $filename) = tempfile( DIR => $dir );
+
+ # or if you don't need to know the filename
+
+ my $fh = tempfile( DIR => $dir );
+
+The File::Temp has been a standard module since Perl 5.6.1. If you
+don't have a modern enough Perl installed, use the C<new_tmpfile>
+class method from the IO::File module to get a filehandle opened for
+reading and writing. Use it if you don't need to know the file's name:
+
+ use IO::File;
+ my $fh = IO::File->new_tmpfile()
+ or die "Unable to make new temporary file: $!";
+
+If you're committed to creating a temporary file by hand, use the
+process ID and/or the current time-value. If you need to have many
+temporary files in one process, use a counter:
+
+ BEGIN {
+ use Fcntl;
+ my $temp_dir = -d '/tmp' ? '/tmp' : $ENV{TMPDIR} || $ENV{TEMP};
+ my $base_name = sprintf "%s/%d-%d-0000", $temp_dir, $$, time;
+
+ sub temp_file {
+ local *FH;
+ my $count = 0;
+ until( defined(fileno(FH)) || $count++ > 100 ) {
+ $base_name =~ s/-(\d+)$/"-" . (1 + $1)/e;
+ # O_EXCL is required for security reasons.
+ sysopen my($fh), $base_name, O_WRONLY|O_EXCL|O_CREAT;
+ }
+
+ if( defined fileno($fh) ) {
+ return ($fh, $base_name);
+ }
+ else {
+ return ();
+ }
+ }
+
+ }
+
+=head2 How can I manipulate fixed-record-length files?
+X<fixed-length> X<file, fixed-length records>
+
+The most efficient way is using L<pack()|perlfunc/"pack"> and
+L<unpack()|perlfunc/"unpack">. This is faster than using
+L<substr()|perlfunc/"substr"> when taking many, many strings. It is
+slower for just a few.
+
+Here is a sample chunk of code to break up and put back together again
+some fixed-format input lines, in this case from the output of a normal,
+Berkeley-style ps:
+
+ # sample input line:
+ # 15158 p5 T 0:00 perl /home/tchrist/scripts/now-what
+ my $PS_T = 'A6 A4 A7 A5 A*';
+ open my $ps, '-|', 'ps';
+ print scalar <$ps>;
+ my @fields = qw( pid tt stat time command );
+ while (<$ps>) {
+ my %process;
+ @process{@fields} = unpack($PS_T, $_);
+ for my $field ( @fields ) {
+ print "$field: <$process{$field}>\n";
+ }
+ print 'line=', pack($PS_T, @process{@fields} ), "\n";
+ }
+
+We've used a hash slice in order to easily handle the fields of each row.
+Storing the keys in an array means it's easy to operate on them as a
+group or loop over them with for. It also avoids polluting the program
+with global variables and using symbolic references.
+
+=head2 How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles?
+X<filehandle, local> X<filehandle, passing> X<filehandle, reference>
+
+As of perl5.6, open() autovivifies file and directory handles
+as references if you pass it an uninitialized scalar variable.
+You can then pass these references just like any other scalar,
+and use them in the place of named handles.
+
+ open my $fh, $file_name;
+
+ open local $fh, $file_name;
+
+ print $fh "Hello World!\n";
+
+ process_file( $fh );
+
+If you like, you can store these filehandles in an array or a hash.
+If you access them directly, they aren't simple scalars and you
+need to give C<print> a little help by placing the filehandle
+reference in braces. Perl can only figure it out on its own when
+the filehandle reference is a simple scalar.
+
+ my @fhs = ( $fh1, $fh2, $fh3 );
+
+ for( $i = 0; $i <= $#fhs; $i++ ) {
+ print {$fhs[$i]} "just another Perl answer, \n";
+ }
+
+Before perl5.6, you had to deal with various typeglob idioms
+which you may see in older code.
+
+ open FILE, "> $filename";
+ process_typeglob( *FILE );
+ process_reference( \*FILE );
+
+ sub process_typeglob { local *FH = shift; print FH "Typeglob!" }
+ sub process_reference { local $fh = shift; print $fh "Reference!" }
+
+If you want to create many anonymous handles, you should
+check out the Symbol or IO::Handle modules.
+
+=head2 How can I use a filehandle indirectly?
+X<filehandle, indirect>
+
+An indirect filehandle is using something other than a symbol
+in a place that a filehandle is expected. Here are ways
+to get indirect filehandles:
+
+ $fh = SOME_FH; # bareword is strict-subs hostile
+ $fh = "SOME_FH"; # strict-refs hostile; same package only
+ $fh = *SOME_FH; # typeglob
+ $fh = \*SOME_FH; # ref to typeglob (bless-able)
+ $fh = *SOME_FH{IO}; # blessed IO::Handle from *SOME_FH typeglob
+
+Or, you can use the C<new> method from one of the IO::* modules to
+create an anonymous filehandle, store that in a scalar variable,
+and use it as though it were a normal filehandle.
+
+ use IO::Handle; # 5.004 or higher
+ my $fh = IO::Handle->new();
+
+Then use any of those as you would a normal filehandle. Anywhere that
+Perl is expecting a filehandle, an indirect filehandle may be used
+instead. An indirect filehandle is just a scalar variable that contains
+a filehandle. Functions like C<print>, C<open>, C<seek>, or
+the C<< <FH> >> diamond operator will accept either a named filehandle
+or a scalar variable containing one:
+
+ ($ifh, $ofh, $efh) = (*STDIN, *STDOUT, *STDERR);
+ print $ofh "Type it: ";
+ my $got = <$ifh>
+ print $efh "What was that: $got";
+
+If you're passing a filehandle to a function, you can write
+the function in two ways:
+
+ sub accept_fh {
+ my $fh = shift;
+ print $fh "Sending to indirect filehandle\n";
+ }
+
+Or it can localize a typeglob and use the filehandle directly:
+
+ sub accept_fh {
+ local *FH = shift;
+ print FH "Sending to localized filehandle\n";
+ }
+
+Both styles work with either objects or typeglobs of real filehandles.
+(They might also work with strings under some circumstances, but this
+is risky.)
+
+ accept_fh(*STDOUT);
+ accept_fh($handle);
+
+In the examples above, we assigned the filehandle to a scalar variable
+before using it. That is because only simple scalar variables, not
+expressions or subscripts of hashes or arrays, can be used with
+built-ins like C<print>, C<printf>, or the diamond operator. Using
+something other than a simple scalar variable as a filehandle is
+illegal and won't even compile:
+
+ my @fd = (*STDIN, *STDOUT, *STDERR);
+ print $fd[1] "Type it: "; # WRONG
+ my $got = <$fd[0]> # WRONG
+ print $fd[2] "What was that: $got"; # WRONG
+
+With C<print> and C<printf>, you get around this by using a block and
+an expression where you would place the filehandle:
+
+ print { $fd[1] } "funny stuff\n";
+ printf { $fd[1] } "Pity the poor %x.\n", 3_735_928_559;
+ # Pity the poor deadbeef.
+
+That block is a proper block like any other, so you can put more
+complicated code there. This sends the message out to one of two places:
+
+ my $ok = -x "/bin/cat";
+ print { $ok ? $fd[1] : $fd[2] } "cat stat $ok\n";
+ print { $fd[ 1+ ($ok || 0) ] } "cat stat $ok\n";
+
+This approach of treating C<print> and C<printf> like object methods
+calls doesn't work for the diamond operator. That's because it's a
+real operator, not just a function with a comma-less argument. Assuming
+you've been storing typeglobs in your structure as we did above, you
+can use the built-in function named C<readline> to read a record just
+as C<< <> >> does. Given the initialization shown above for @fd, this
+would work, but only because readline() requires a typeglob. It doesn't
+work with objects or strings, which might be a bug we haven't fixed yet.
+
+ $got = readline($fd[0]);
+
+Let it be noted that the flakiness of indirect filehandles is not
+related to whether they're strings, typeglobs, objects, or anything else.
+It's the syntax of the fundamental operators. Playing the object
+game doesn't help you at all here.
+
+=head2 How can I set up a footer format to be used with write()?
+X<footer>
+
+There's no builtin way to do this, but L<perlform> has a couple of
+techniques to make it possible for the intrepid hacker.
+
+=head2 How can I write() into a string?
+X<write, into a string>
+
+See L<perlform/"Accessing Formatting Internals"> for an C<swrite()> function.
+
+=head2 How can I open a filehandle to a string?
+X<string> X<open> X<IO::String> X<filehandle>
+
+(contributed by Peter J. Holzer, hjp-usenet2@hjp.at)
+
+Since Perl 5.8.0 a file handle referring to a string can be created by
+calling open with a reference to that string instead of the filename.
+This file handle can then be used to read from or write to the string:
+
+ open(my $fh, '>', \$string) or die "Could not open string for writing";
+ print $fh "foo\n";
+ print $fh "bar\n"; # $string now contains "foo\nbar\n"
+
+ open(my $fh, '<', \$string) or die "Could not open string for reading";
+ my $x = <$fh>; # $x now contains "foo\n"
+
+With older versions of Perl, the C<IO::String> module provides similar
+functionality.
+
+=head2 How can I output my numbers with commas added?
+X<number, commify>
+
+(contributed by brian d foy and Benjamin Goldberg)
+
+You can use L<Number::Format> to separate places in a number.
+It handles locale information for those of you who want to insert
+full stops instead (or anything else that they want to use,
+really).
+
+This subroutine will add commas to your number:
+
+ sub commify {
+ local $_ = shift;
+ 1 while s/^([-+]?\d+)(\d{3})/$1,$2/;
+ return $_;
+ }
+
+This regex from Benjamin Goldberg will add commas to numbers:
+
+ s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\d))/$1,/g;
+
+It is easier to see with comments:
+
+ s/(
+ ^[-+]? # beginning of number.
+ \d+? # first digits before first comma
+ (?= # followed by, (but not included in the match) :
+ (?>(?:\d{3})+) # some positive multiple of three digits.
+ (?!\d) # an *exact* multiple, not x * 3 + 1 or whatever.
+ )
+ | # or:
+ \G\d{3} # after the last group, get three digits
+ (?=\d) # but they have to have more digits after them.
+ )/$1,/xg;
+
+=head2 How can I translate tildes (~) in a filename?
+X<tilde> X<tilde expansion>
+
+Use the E<lt>E<gt> (C<glob()>) operator, documented in L<perlfunc>.
+Versions of Perl older than 5.6 require that you have a shell
+installed that groks tildes. Later versions of Perl have this feature
+built in. The C<File::KGlob> module (available from CPAN) gives more
+portable glob functionality.
+
+Within Perl, you may use this directly:
+
+ $filename =~ s{
+ ^ ~ # find a leading tilde
+ ( # save this in $1
+ [^/] # a non-slash character
+ * # repeated 0 or more times (0 means me)
+ )
+ }{
+ $1
+ ? (getpwnam($1))[7]
+ : ( $ENV{HOME} || $ENV{LOGDIR} )
+ }ex;
+
+=head2 How come when I open a file read-write it wipes it out?
+X<clobber> X<read-write> X<clobbering> X<truncate> X<truncating>
+
+Because you're using something like this, which truncates the file and
+I<then> gives you read-write access:
+
+ open my $fh, '+>', '/path/name'; # WRONG (almost always)
+
+Whoops. You should instead use this, which will fail if the file
+doesn't exist.
+
+ open my $fh, '+<', '/path/name'; # open for update
+
+Using ">" always clobbers or creates. Using "<" never does
+either. The "+" doesn't change this.
+
+Here are examples of many kinds of file opens. Those using sysopen()
+all assume
+
+ use Fcntl;
+
+To open file for reading:
+
+ open my $fh, '<', $path or die $!;
+ sysopen my $fh, $path, O_RDONLY or die $!;
+
+To open file for writing, create new file if needed or else truncate old file:
+
+ open my $fh, '>', $path or die $!;
+ sysopen my $fh, $path, O_WRONLY|O_TRUNC|O_CREAT or die $!;
+ sysopen my $fh, $path, O_WRONLY|O_TRUNC|O_CREAT, 0666 or die $!;
+
+To open file for writing, create new file, file must not exist:
+
+ sysopen my $fh, $path, O_WRONLY|O_EXCL|O_CREAT or die $!;
+ sysopen my $fh, $path, O_WRONLY|O_EXCL|O_CREAT, 0666 or die $!;
+
+To open file for appending, create if necessary:
+
+ open my $fh, '>>' $path or die $!;
+ sysopen my $fh, $path, O_WRONLY|O_APPEND|O_CREAT or die $!;
+ sysopen my $fh, $path, O_WRONLY|O_APPEND|O_CREAT, 0666 or die $!;
+
+To open file for appending, file must exist:
+
+ sysopen my $fh, $path, O_WRONLY|O_APPEND or die $!;
+
+To open file for update, file must exist:
+
+ open my $fh, '+<', $path or die $!;
+ sysopen my $fh, $path, O_RDWR or die $!;
+
+To open file for update, create file if necessary:
+
+ sysopen my $fh, $path, O_RDWR|O_CREAT or die $!;
+ sysopen my $fh, $path, O_RDWR|O_CREAT, 0666 or die $!;
+
+To open file for update, file must not exist:
+
+ sysopen my $fh, $path, O_RDWR|O_EXCL|O_CREAT or die $!;
+ sysopen my $fh, $path, O_RDWR|O_EXCL|O_CREAT, 0666 or die $!;
+
+To open a file without blocking, creating if necessary:
+
+ sysopen my $fh, '/foo/somefile', O_WRONLY|O_NDELAY|O_CREAT
+ or die "can't open /foo/somefile: $!":
+
+Be warned that neither creation nor deletion of files is guaranteed to
+be an atomic operation over NFS. That is, two processes might both
+successfully create or unlink the same file! Therefore O_EXCL
+isn't as exclusive as you might wish.
+
+See also the new L<perlopentut>.
+
+=head2 Why do I sometimes get an "Argument list too long" when I use E<lt>*E<gt>?
+X<argument list too long>
+
+The C<< <> >> operator performs a globbing operation (see above).
+In Perl versions earlier than v5.6.0, the internal glob() operator forks
+csh(1) to do the actual glob expansion, but
+csh can't handle more than 127 items and so gives the error message
+C<Argument list too long>. People who installed tcsh as csh won't
+have this problem, but their users may be surprised by it.
+
+To get around this, either upgrade to Perl v5.6.0 or later, do the glob
+yourself with readdir() and patterns, or use a module like File::KGlob,
+one that doesn't use the shell to do globbing.
+
+=head2 Is there a leak/bug in glob()?
+X<glob>
+
+(contributed by brian d foy)
+
+Starting with Perl 5.6.0, C<glob> is implemented internally rather
+than relying on an external resource. As such, memory issues with
+C<glob> aren't a problem in modern perls.
+
+=head2 How can I open a file with a leading ">" or trailing blanks?
+X<filename, special characters>
+
+(contributed by Brian McCauley)
+
+The special two argument form of Perl's open() function ignores
+trailing blanks in filenames and infers the mode from certain leading
+characters (or a trailing "|"). In older versions of Perl this was the
+only version of open() and so it is prevalent in old code and books.
+
+Unless you have a particular reason to use the two argument form you
+should use the three argument form of open() which does not treat any
+characters in the filename as special.
+
+ open my $fh, "<", " file "; # filename is " file "
+ open my $fh, ">", ">file"; # filename is ">file"
+
+=head2 How can I reliably rename a file?
+X<rename> X<mv> X<move> X<file, rename>
+
+If your operating system supports a proper mv(1) utility or its
+functional equivalent, this works:
+
+ rename($old, $new) or system("mv", $old, $new);
+
+It may be more portable to use the C<File::Copy> module instead.
+You just copy to the new file to the new name (checking return
+values), then delete the old one. This isn't really the same
+semantically as a C<rename()>, which preserves meta-information like
+permissions, timestamps, inode info, etc.
+
+=head2 How can I lock a file?
+X<lock> X<file, lock> X<flock>
+
+Perl's builtin flock() function (see L<perlfunc> for details) will call
+flock(2) if that exists, fcntl(2) if it doesn't (on perl version 5.004 and
+later), and lockf(3) if neither of the two previous system calls exists.
+On some systems, it may even use a different form of native locking.
+Here are some gotchas with Perl's flock():
+
+=over 4
+
+=item 1
+
+Produces a fatal error if none of the three system calls (or their
+close equivalent) exists.
+
+=item 2
+
+lockf(3) does not provide shared locking, and requires that the
+filehandle be open for writing (or appending, or read/writing).
+
+=item 3
+
+Some versions of flock() can't lock files over a network (e.g. on NFS file
+systems), so you'd need to force the use of fcntl(2) when you build Perl.
+But even this is dubious at best. See the flock entry of L<perlfunc>
+and the F<INSTALL> file in the source distribution for information on
+building Perl to do this.
+
+Two potentially non-obvious but traditional flock semantics are that
+it waits indefinitely until the lock is granted, and that its locks are
+I<merely advisory>. Such discretionary locks are more flexible, but
+offer fewer guarantees. This means that files locked with flock() may
+be modified by programs that do not also use flock(). Cars that stop
+for red lights get on well with each other, but not with cars that don't
+stop for red lights. See the perlport manpage, your port's specific
+documentation, or your system-specific local manpages for details. It's
+best to assume traditional behavior if you're writing portable programs.
+(If you're not, you should as always feel perfectly free to write
+for your own system's idiosyncrasies (sometimes called "features").
+Slavish adherence to portability concerns shouldn't get in the way of
+your getting your job done.)
+
+For more information on file locking, see also
+L<perlopentut/"File Locking"> if you have it (new for 5.6).
+
+=back
+
+=head2 Why can't I just open(FH, "E<gt>file.lock")?
+X<lock, lockfile race condition>
+
+A common bit of code B<NOT TO USE> is this:
+
+ sleep(3) while -e 'file.lock'; # PLEASE DO NOT USE
+ open my $lock, '>', 'file.lock'; # THIS BROKEN CODE
+
+This is a classic race condition: you take two steps to do something
+which must be done in one. That's why computer hardware provides an
+atomic test-and-set instruction. In theory, this "ought" to work:
+
+ sysopen my $fh, "file.lock", O_WRONLY|O_EXCL|O_CREAT
+ or die "can't open file.lock: $!";
+
+except that lamentably, file creation (and deletion) is not atomic
+over NFS, so this won't work (at least, not every time) over the net.
+Various schemes involving link() have been suggested, but
+these tend to involve busy-wait, which is also less than desirable.
+
+=head2 I still don't get locking. I just want to increment the number in the file. How can I do this?
+X<counter> X<file, counter>
+
+Didn't anyone ever tell you web-page hit counters were useless?
+They don't count number of hits, they're a waste of time, and they serve
+only to stroke the writer's vanity. It's better to pick a random number;
+they're more realistic.
+
+Anyway, this is what you can do if you can't help yourself.
+
+ use Fcntl qw(:DEFAULT :flock);
+ sysopen my $fh, "numfile", O_RDWR|O_CREAT or die "can't open numfile: $!";
+ flock $fh, LOCK_EX or die "can't flock numfile: $!";
+ my $num = <$fh> || 0;
+ seek $fh, 0, 0 or die "can't rewind numfile: $!";
+ truncate $fh, 0 or die "can't truncate numfile: $!";
+ (print $fh $num+1, "\n") or die "can't write numfile: $!";
+ close $fh or die "can't close numfile: $!";
+
+Here's a much better web-page hit counter:
+
+ $hits = int( (time() - 850_000_000) / rand(1_000) );
+
+If the count doesn't impress your friends, then the code might. :-)
+
+=head2 All I want to do is append a small amount of text to the end of a file. Do I still have to use locking?
+X<append> X<file, append>
+
+If you are on a system that correctly implements C<flock> and you use
+the example appending code from "perldoc -f flock" everything will be
+OK even if the OS you are on doesn't implement append mode correctly
+(if such a system exists.) So if you are happy to restrict yourself to
+OSs that implement C<flock> (and that's not really much of a
+restriction) then that is what you should do.
+
+If you know you are only going to use a system that does correctly
+implement appending (i.e. not Win32) then you can omit the C<seek>
+from the code in the previous answer.
+
+If you know you are only writing code to run on an OS and filesystem
+that does implement append mode correctly (a local filesystem on a
+modern Unix for example), and you keep the file in block-buffered mode
+and you write less than one buffer-full of output between each manual
+flushing of the buffer then each bufferload is almost guaranteed to be
+written to the end of the file in one chunk without getting
+intermingled with anyone else's output. You can also use the
+C<syswrite> function which is simply a wrapper around your system's
+C<write(2)> system call.
+
+There is still a small theoretical chance that a signal will interrupt
+the system level C<write()> operation before completion. There is also
+a possibility that some STDIO implementations may call multiple system
+level C<write()>s even if the buffer was empty to start. There may be
+some systems where this probability is reduced to zero, and this is
+not a concern when using C<:perlio> instead of your system's STDIO.
+
+=head2 How do I randomly update a binary file?
+X<file, binary patch>
+
+If you're just trying to patch a binary, in many cases something as
+simple as this works:
+
+ perl -i -pe 's{window manager}{window mangler}g' /usr/bin/emacs
+
+However, if you have fixed sized records, then you might do something more
+like this:
+
+ $RECSIZE = 220; # size of record, in bytes
+ $recno = 37; # which record to update
+ open my $fh, '+<', 'somewhere' or die "can't update somewhere: $!";
+ seek $fh, $recno * $RECSIZE, 0;
+ read $fh, $record, $RECSIZE == $RECSIZE or die "can't read record $recno: $!";
+ # munge the record
+ seek $fh, -$RECSIZE, 1;
+ print $fh $record;
+ close $fh;
+
+Locking and error checking are left as an exercise for the reader.
+Don't forget them or you'll be quite sorry.
+
+=head2 How do I get a file's timestamp in perl?
+X<timestamp> X<file, timestamp>
+
+If you want to retrieve the time at which the file was last read,
+written, or had its meta-data (owner, etc) changed, you use the B<-A>,
+B<-M>, or B<-C> file test operations as documented in L<perlfunc>.
+These retrieve the age of the file (measured against the start-time of
+your program) in days as a floating point number. Some platforms may
+not have all of these times. See L<perlport> for details. To retrieve
+the "raw" time in seconds since the epoch, you would call the stat
+function, then use C<localtime()>, C<gmtime()>, or
+C<POSIX::strftime()> to convert this into human-readable form.
+
+Here's an example:
+
+ my $write_secs = (stat($file))[9];
+ printf "file %s updated at %s\n", $file,
+ scalar localtime($write_secs);
+
+If you prefer something more legible, use the File::stat module
+(part of the standard distribution in version 5.004 and later):
+
+ # error checking left as an exercise for reader.
+ use File::stat;
+ use Time::localtime;
+ my $date_string = ctime(stat($file)->mtime);
+ print "file $file updated at $date_string\n";
+
+The POSIX::strftime() approach has the benefit of being,
+in theory, independent of the current locale. See L<perllocale>
+for details.
+
+=head2 How do I set a file's timestamp in perl?
+X<timestamp> X<file, timestamp>
+
+You use the utime() function documented in L<perlfunc/utime>.
+By way of example, here's a little program that copies the
+read and write times from its first argument to all the rest
+of them.
+
+ if (@ARGV < 2) {
+ die "usage: cptimes timestamp_file other_files ...\n";
+ }
+ my $timestamp = shift;
+ my($atime, $mtime) = (stat($timestamp))[8,9];
+ utime $atime, $mtime, @ARGV;
+
+Error checking is, as usual, left as an exercise for the reader.
+
+The perldoc for utime also has an example that has the same
+effect as touch(1) on files that I<already exist>.
+
+Certain file systems have a limited ability to store the times
+on a file at the expected level of precision. For example, the
+FAT and HPFS filesystem are unable to create dates on files with
+a finer granularity than two seconds. This is a limitation of
+the filesystems, not of utime().
+
+=head2 How do I print to more than one file at once?
+X<print, to multiple files>
+
+To connect one filehandle to several output filehandles,
+you can use the IO::Tee or Tie::FileHandle::Multiplex modules.
+
+If you only have to do this once, you can print individually
+to each filehandle.
+
+ for my $fh (FH1, FH2, FH3) { print $fh "whatever\n" }
+
+=head2 How can I read in an entire file all at once?
+X<slurp> X<file, slurping>
+
+Are you sure you want to read the entire file and store it in memory?
+If you mmap the file, you can virtually load the entire file into a
+string without actually storing it in memory:
+
+ use File::Map qw(map_file);
+
+ map_file my $string, $filename;
+
+Once mapped, you can treat C<$string> as you would any other string.
+Since you don't actually load the data, mmap-ing is very fast and does
+not increase your memory footprint.
+
+If you really want to load the entire file, you can use the
+C<File::Slurp> module to do it in one step.
+
+ use File::Slurp;
+
+ my $all_of_it = read_file($filename); # entire file in scalar
+ my @all_lines = read_file($filename); # one line per element
+
+The customary Perl approach for processing all the lines in a file is to
+do so one line at a time:
+
+ open my $input, '<', $file or die "can't open $file: $!";
+ while (<$input>) {
+ chomp;
+ # do something with $_
+ }
+ close $input or die "can't close $file: $!";
+
+This is tremendously more efficient than reading the entire file into
+memory as an array of lines and then processing it one element at a time,
+which is often--if not almost always--the wrong approach. Whenever
+you see someone do this:
+
+ my @lines = <INPUT>;
+
+You should think long and hard about why you need everything loaded at
+once. It's just not a scalable solution. You might also find it more
+fun to use the standard Tie::File module, or the DB_File module's
+$DB_RECNO bindings, which allow you to tie an array to a file so that
+accessing an element the array actually accesses the corresponding
+line in the file.
+
+You can read the entire filehandle contents into a scalar.
+
+ {
+ local $/;
+ open my $fh, '<', $file or die "can't open $file: $!";
+ $var = <$fh>;
+ }
+
+That temporarily undefs your record separator, and will automatically
+close the file at block exit. If the file is already open, just use this:
+
+ $var = do { local $/; <$fh> };
+
+For ordinary files you can also use the read function.
+
+ read( $fh, $var, -s $fh );
+
+The third argument tests the byte size of the data on the INPUT filehandle
+and reads that many bytes into the buffer $var.
+
+=head2 How can I read in a file by paragraphs?
+X<file, reading by paragraphs>
+
+Use the C<$/> variable (see L<perlvar> for details). You can either
+set it to C<""> to eliminate empty paragraphs (C<"abc\n\n\n\ndef">,
+for instance, gets treated as two paragraphs and not three), or
+C<"\n\n"> to accept empty paragraphs.
+
+Note that a blank line must have no blanks in it. Thus
+S<C<"fred\n \nstuff\n\n">> is one paragraph, but C<"fred\n\nstuff\n\n"> is two.
+
+=head2 How can I read a single character from a file? From the keyboard?
+X<getc> X<file, reading one character at a time>
+
+You can use the builtin C<getc()> function for most filehandles, but
+it won't (easily) work on a terminal device. For STDIN, either use
+the Term::ReadKey module from CPAN or use the sample code in
+L<perlfunc/getc>.
+
+If your system supports the portable operating system programming
+interface (POSIX), you can use the following code, which you'll note
+turns off echo processing as well.
+
+ #!/usr/bin/perl -w
+ use strict;
+ $| = 1;
+ for (1..4) {
+ print "gimme: ";
+ my $got = getone();
+ print "--> $got\n";
+ }
+ exit;
+
+ BEGIN {
+ use POSIX qw(:termios_h);
+
+ my ($term, $oterm, $echo, $noecho, $fd_stdin);
+
+ my $fd_stdin = fileno(STDIN);
+
+ $term = POSIX::Termios->new();
+ $term->getattr($fd_stdin);
+ $oterm = $term->getlflag();
+
+ $echo = ECHO | ECHOK | ICANON;
+ $noecho = $oterm & ~$echo;
+
+ sub cbreak {
+ $term->setlflag($noecho);
+ $term->setcc(VTIME, 1);
+ $term->setattr($fd_stdin, TCSANOW);
+ }
+
+ sub cooked {
+ $term->setlflag($oterm);
+ $term->setcc(VTIME, 0);
+ $term->setattr($fd_stdin, TCSANOW);
+ }
+
+ sub getone {
+ my $key = '';
+ cbreak();
+ sysread(STDIN, $key, 1);
+ cooked();
+ return $key;
+ }
+
+ }
+
+ END { cooked() }
+
+The Term::ReadKey module from CPAN may be easier to use. Recent versions
+include also support for non-portable systems as well.
+
+ use Term::ReadKey;
+ open my $tty, '<', '/dev/tty';
+ print "Gimme a char: ";
+ ReadMode "raw";
+ my $key = ReadKey 0, $tty;
+ ReadMode "normal";
+ printf "\nYou said %s, char number %03d\n",
+ $key, ord $key;
+
+=head2 How can I tell whether there's a character waiting on a filehandle?
+
+The very first thing you should do is look into getting the Term::ReadKey
+extension from CPAN. As we mentioned earlier, it now even has limited
+support for non-portable (read: not open systems, closed, proprietary,
+not POSIX, not Unix, etc.) systems.
+
+You should also check out the Frequently Asked Questions list in
+comp.unix.* for things like this: the answer is essentially the same.
+It's very system dependent. Here's one solution that works on BSD
+systems:
+
+ sub key_ready {
+ my($rin, $nfd);
+ vec($rin, fileno(STDIN), 1) = 1;
+ return $nfd = select($rin,undef,undef,0);
+ }
+
+If you want to find out how many characters are waiting, there's
+also the FIONREAD ioctl call to be looked at. The I<h2ph> tool that
+comes with Perl tries to convert C include files to Perl code, which
+can be C<require>d. FIONREAD ends up defined as a function in the
+I<sys/ioctl.ph> file:
+
+ require 'sys/ioctl.ph';
+
+ $size = pack("L", 0);
+ ioctl(FH, FIONREAD(), $size) or die "Couldn't call ioctl: $!\n";
+ $size = unpack("L", $size);
+
+If I<h2ph> wasn't installed or doesn't work for you, you can
+I<grep> the include files by hand:
+
+ % grep FIONREAD /usr/include/*/*
+ /usr/include/asm/ioctls.h:#define FIONREAD 0x541B
+
+Or write a small C program using the editor of champions:
+
+ % cat > fionread.c
+ #include <sys/ioctl.h>
+ main() {
+ printf("%#08x\n", FIONREAD);
+ }
+ ^D
+ % cc -o fionread fionread.c
+ % ./fionread
+ 0x4004667f
+
+And then hard code it, leaving porting as an exercise to your successor.
+
+ $FIONREAD = 0x4004667f; # XXX: opsys dependent
+
+ $size = pack("L", 0);
+ ioctl(FH, $FIONREAD, $size) or die "Couldn't call ioctl: $!\n";
+ $size = unpack("L", $size);
+
+FIONREAD requires a filehandle connected to a stream, meaning that sockets,
+pipes, and tty devices work, but I<not> files.
+
+=head2 How do I do a C<tail -f> in perl?
+X<tail> X<IO::Handle> X<File::Tail> X<clearerr>
+
+First try
+
+ seek(GWFILE, 0, 1);
+
+The statement C<seek(GWFILE, 0, 1)> doesn't change the current position,
+but it does clear the end-of-file condition on the handle, so that the
+next C<< <GWFILE> >> makes Perl try again to read something.
+
+If that doesn't work (it relies on features of your stdio implementation),
+then you need something more like this:
+
+ for (;;) {
+ for ($curpos = tell(GWFILE); <GWFILE>; $curpos = tell(GWFILE)) {
+ # search for some stuff and put it into files
+ }
+ # sleep for a while
+ seek(GWFILE, $curpos, 0); # seek to where we had been
+ }
+
+If this still doesn't work, look into the C<clearerr> method
+from C<IO::Handle>, which resets the error and end-of-file states
+on the handle.
+
+There's also a C<File::Tail> module from CPAN.
+
+=head2 How do I dup() a filehandle in Perl?
+X<dup>
+
+If you check L<perlfunc/open>, you'll see that several of the ways
+to call open() should do the trick. For example:
+
+ open my $log, '>>', '/foo/logfile';
+ open STDERR, '>&LOG';
+
+Or even with a literal numeric descriptor:
+
+ my $fd = $ENV{MHCONTEXTFD};
+ open $mhcontext, "<&=$fd"; # like fdopen(3S)
+
+Note that "<&STDIN" makes a copy, but "<&=STDIN" make
+an alias. That means if you close an aliased handle, all
+aliases become inaccessible. This is not true with
+a copied one.
+
+Error checking, as always, has been left as an exercise for the reader.
+
+=head2 How do I close a file descriptor by number?
+X<file, closing file descriptors> X<POSIX> X<close>
+
+If, for some reason, you have a file descriptor instead of a
+filehandle (perhaps you used C<POSIX::open>), you can use the
+C<close()> function from the C<POSIX> module:
+
+ use POSIX ();
+
+ POSIX::close( $fd );
+
+This should rarely be necessary, as the Perl C<close()> function is to be
+used for things that Perl opened itself, even if it was a dup of a
+numeric descriptor as with C<MHCONTEXT> above. But if you really have
+to, you may be able to do this:
+
+ require 'sys/syscall.ph';
+ my $rc = syscall(&SYS_close, $fd + 0); # must force numeric
+ die "can't sysclose $fd: $!" unless $rc == -1;
+
+Or, just use the fdopen(3S) feature of C<open()>:
+
+ {
+ open my( $fh ), "<&=$fd" or die "Cannot reopen fd=$fd: $!";
+ close $fh;
+ }
+
+=head2 Why can't I use "C:\temp\foo" in DOS paths? Why doesn't `C:\temp\foo.exe` work?
+X<filename, DOS issues>
+
+Whoops! You just put a tab and a formfeed into that filename!
+Remember that within double quoted strings ("like\this"), the
+backslash is an escape character. The full list of these is in
+L<perlop/Quote and Quote-like Operators>. Unsurprisingly, you don't
+have a file called "c:(tab)emp(formfeed)oo" or
+"c:(tab)emp(formfeed)oo.exe" on your legacy DOS filesystem.
+
+Either single-quote your strings, or (preferably) use forward slashes.
+Since all DOS and Windows versions since something like MS-DOS 2.0 or so
+have treated C</> and C<\> the same in a path, you might as well use the
+one that doesn't clash with Perl--or the POSIX shell, ANSI C and C++,
+awk, Tcl, Java, or Python, just to mention a few. POSIX paths
+are more portable, too.
+
+=head2 Why doesn't glob("*.*") get all the files?
+X<glob>
+
+Because even on non-Unix ports, Perl's glob function follows standard
+Unix globbing semantics. You'll need C<glob("*")> to get all (non-hidden)
+files. This makes glob() portable even to legacy systems. Your
+port may include proprietary globbing functions as well. Check its
+documentation for details.
+
+=head2 Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl?
+
+This is elaborately and painstakingly described in the
+F<file-dir-perms> article in the "Far More Than You Ever Wanted To
+Know" collection in http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz .
+
+The executive summary: learn how your filesystem works. The
+permissions on a file say what can happen to the data in that file.
+The permissions on a directory say what can happen to the list of
+files in that directory. If you delete a file, you're removing its
+name from the directory (so the operation depends on the permissions
+of the directory, not of the file). If you try to write to the file,
+the permissions of the file govern whether you're allowed to.
+
+=head2 How do I select a random line from a file?
+X<file, selecting a random line>
+
+Short of loading the file into a database or pre-indexing the lines in
+the file, there are a couple of things that you can do.
+
+Here's a reservoir-sampling algorithm from the Camel Book:
+
+ srand;
+ rand($.) < 1 && ($line = $_) while <>;
+
+This has a significant advantage in space over reading the whole file
+in. You can find a proof of this method in I<The Art of Computer
+Programming>, Volume 2, Section 3.4.2, by Donald E. Knuth.
+
+You can use the C<File::Random> module which provides a function
+for that algorithm:
+
+ use File::Random qw/random_line/;
+ my $line = random_line($filename);
+
+Another way is to use the C<Tie::File> module, which treats the entire
+file as an array. Simply access a random array element.
+
+=head2 Why do I get weird spaces when I print an array of lines?
+
+(contributed by brian d foy)
+
+If you are seeing spaces between the elements of your array when
+you print the array, you are probably interpolating the array in
+double quotes:
+
+ my @animals = qw(camel llama alpaca vicuna);
+ print "animals are: @animals\n";
+
+It's the double quotes, not the C<print>, doing this. Whenever you
+interpolate an array in a double quote context, Perl joins the
+elements with spaces (or whatever is in C<$">, which is a space by
+default):
+
+ animals are: camel llama alpaca vicuna
+
+This is different than printing the array without the interpolation:
+
+ my @animals = qw(camel llama alpaca vicuna);
+ print "animals are: ", @animals, "\n";
+
+Now the output doesn't have the spaces between the elements because
+the elements of C<@animals> simply become part of the list to
+C<print>:
+
+ animals are: camelllamaalpacavicuna
+
+You might notice this when each of the elements of C<@array> end with
+a newline. You expect to print one element per line, but notice that
+every line after the first is indented:
+
+ this is a line
+ this is another line
+ this is the third line
+
+That extra space comes from the interpolation of the array. If you
+don't want to put anything between your array elements, don't use the
+array in double quotes. You can send it to print without them:
+
+ print @lines;
+
+=head2 How do I traverse a directory tree?
+
+(contributed by brian d foy)
+
+The C<File::Find> module, which comes with Perl, does all of the hard
+work to traverse a directory structure. It comes with Perl. You simply
+call the C<find> subroutine with a callback subroutine and the
+directories you want to traverse:
+
+ use File::Find;
+
+ find( \&wanted, @directories );
+
+ sub wanted {
+ # full path in $File::Find::name
+ # just filename in $_
+ ... do whatever you want to do ...
+ }
+
+The C<File::Find::Closures>, which you can download from CPAN, provides
+many ready-to-use subroutines that you can use with C<File::Find>.
+
+The C<File::Finder>, which you can download from CPAN, can help you
+create the callback subroutine using something closer to the syntax of
+the C<find> command-line utility:
+
+ use File::Find;
+ use File::Finder;
+
+ my $deep_dirs = File::Finder->depth->type('d')->ls->exec('rmdir','{}');
+
+ find( $deep_dirs->as_options, @places );
+
+The C<File::Find::Rule> module, which you can download from CPAN, has
+a similar interface, but does the traversal for you too:
+
+ use File::Find::Rule;
+
+ my @files = File::Find::Rule->file()
+ ->name( '*.pm' )
+ ->in( @INC );
+
+=head2 How do I delete a directory tree?
+
+(contributed by brian d foy)
+
+If you have an empty directory, you can use Perl's built-in C<rmdir>.
+If the directory is not empty (so, no files or subdirectories), you
+either have to empty it yourself (a lot of work) or use a module to
+help you.
+
+The C<File::Path> module, which comes with Perl, has a C<remove_tree>
+which can take care of all of the hard work for you:
+
+ use File::Path qw(remove_tree);
+
+ remove_tree( @directories );
+
+The C<File::Path> module also has a legacy interface to the older
+C<rmtree> subroutine.
+
+=head2 How do I copy an entire directory?
+
+(contributed by Shlomi Fish)
+
+To do the equivalent of C<cp -R> (i.e. copy an entire directory tree
+recursively) in portable Perl, you'll either need to write something yourself
+or find a good CPAN module such as L<File::Copy::Recursive>.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples here are in the public
+domain. You are permitted and encouraged to use this code and any
+derivatives thereof in your own programs for fun or for profit as you
+see fit. A simple comment in the code giving credit to the FAQ would
+be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq6.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq6.pod
new file mode 100644
index 00000000000..40965d09fcb
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq6.pod
@@ -0,0 +1,1143 @@
+=head1 NAME
+
+perlfaq6 - Regular Expressions
+
+=head1 DESCRIPTION
+
+This section is surprisingly small because the rest of the FAQ is
+littered with answers involving regular expressions. For example,
+decoding a URL and checking whether something is a number are handled
+with regular expressions, but those answers are found elsewhere in
+this document (in L<perlfaq9>: "How do I decode or create those %-encodings
+on the web" and L<perlfaq4>: "How do I determine whether a scalar is
+a number/whole/integer/float", to be precise).
+
+=head2 How can I hope to use regular expressions without creating illegible and unmaintainable code?
+X<regex, legibility> X<regexp, legibility>
+X<regular expression, legibility> X</x>
+
+Three techniques can make regular expressions maintainable and
+understandable.
+
+=over 4
+
+=item Comments Outside the Regex
+
+Describe what you're doing and how you're doing it, using normal Perl
+comments.
+
+ # turn the line into the first word, a colon, and the
+ # number of characters on the rest of the line
+ s/^(\w+)(.*)/ lc($1) . ":" . length($2) /meg;
+
+=item Comments Inside the Regex
+
+The C</x> modifier causes whitespace to be ignored in a regex pattern
+(except in a character class and a few other places), and also allows you to
+use normal comments there, too. As you can imagine, whitespace and comments
+help a lot.
+
+C</x> lets you turn this:
+
+ s{<(?:[^>'"]*|".*?"|'.*?')+>}{}gs;
+
+into this:
+
+ s{ < # opening angle bracket
+ (?: # Non-backreffing grouping paren
+ [^>'"] * # 0 or more things that are neither > nor ' nor "
+ | # or else
+ ".*?" # a section between double quotes (stingy match)
+ | # or else
+ '.*?' # a section between single quotes (stingy match)
+ ) + # all occurring one or more times
+ > # closing angle bracket
+ }{}gsx; # replace with nothing, i.e. delete
+
+It's still not quite so clear as prose, but it is very useful for
+describing the meaning of each part of the pattern.
+
+=item Different Delimiters
+
+While we normally think of patterns as being delimited with C</>
+characters, they can be delimited by almost any character. L<perlre>
+describes this. For example, the C<s///> above uses braces as
+delimiters. Selecting another delimiter can avoid quoting the
+delimiter within the pattern:
+
+ s/\/usr\/local/\/usr\/share/g; # bad delimiter choice
+ s#/usr/local#/usr/share#g; # better
+
+=back
+
+=head2 I'm having trouble matching over more than one line. What's wrong?
+X<regex, multiline> X<regexp, multiline> X<regular expression, multiline>
+
+Either you don't have more than one line in the string you're looking
+at (probably), or else you aren't using the correct modifier(s) on
+your pattern (possibly).
+
+There are many ways to get multiline data into a string. If you want
+it to happen automatically while reading input, you'll want to set $/
+(probably to '' for paragraphs or C<undef> for the whole file) to
+allow you to read more than one line at a time.
+
+Read L<perlre> to help you decide which of C</s> and C</m> (or both)
+you might want to use: C</s> allows dot to include newline, and C</m>
+allows caret and dollar to match next to a newline, not just at the
+end of the string. You do need to make sure that you've actually
+got a multiline string in there.
+
+For example, this program detects duplicate words, even when they span
+line breaks (but not paragraph ones). For this example, we don't need
+C</s> because we aren't using dot in a regular expression that we want
+to cross line boundaries. Neither do we need C</m> because we aren't
+wanting caret or dollar to match at any point inside the record next
+to newlines. But it's imperative that $/ be set to something other
+than the default, or else we won't actually ever have a multiline
+record read in.
+
+ $/ = ''; # read in whole paragraph, not just one line
+ while ( <> ) {
+ while ( /\b([\w'-]+)(\s+\1)+\b/gi ) { # word starts alpha
+ print "Duplicate $1 at paragraph $.\n";
+ }
+ }
+
+Here's code that finds sentences that begin with "From " (which would
+be mangled by many mailers):
+
+ $/ = ''; # read in whole paragraph, not just one line
+ while ( <> ) {
+ while ( /^From /gm ) { # /m makes ^ match next to \n
+ print "leading from in paragraph $.\n";
+ }
+ }
+
+Here's code that finds everything between START and END in a paragraph:
+
+ undef $/; # read in whole file, not just one line or paragraph
+ while ( <> ) {
+ while ( /START(.*?)END/sgm ) { # /s makes . cross line boundaries
+ print "$1\n";
+ }
+ }
+
+=head2 How can I pull out lines between two patterns that are themselves on different lines?
+X<..>
+
+You can use Perl's somewhat exotic C<..> operator (documented in
+L<perlop>):
+
+ perl -ne 'print if /START/ .. /END/' file1 file2 ...
+
+If you wanted text and not lines, you would use
+
+ perl -0777 -ne 'print "$1\n" while /START(.*?)END/gs' file1 file2 ...
+
+But if you want nested occurrences of C<START> through C<END>, you'll
+run up against the problem described in the question in this section
+on matching balanced text.
+
+Here's another example of using C<..>:
+
+ while (<>) {
+ $in_header = 1 .. /^$/;
+ $in_body = /^$/ .. eof;
+ # now choose between them
+ } continue {
+ $. = 0 if eof; # fix $.
+ }
+
+=head2 How do I match XML, HTML, or other nasty, ugly things with a regex?
+X<regex, XML> X<regex, HTML> X<XML> X<HTML> X<pain> X<frustration>
+X<sucking out, will to live>
+
+(contributed by brian d foy)
+
+If you just want to get work done, use a module and forget about the
+regular expressions. The C<XML::Parser> and C<HTML::Parser> modules
+are good starts, although each namespace has other parsing modules
+specialized for certain tasks and different ways of doing it. Start at
+CPAN Search ( http://search.cpan.org ) and wonder at all the work people
+have done for you already! :)
+
+The problem with things such as XML is that they have balanced text
+containing multiple levels of balanced text, but sometimes it isn't
+balanced text, as in an empty tag (C<< <br/> >>, for instance). Even then,
+things can occur out-of-order. Just when you think you've got a
+pattern that matches your input, someone throws you a curveball.
+
+If you'd like to do it the hard way, scratching and clawing your way
+toward a right answer but constantly being disappointed, besieged by
+bug reports, and weary from the inordinate amount of time you have to
+spend reinventing a triangular wheel, then there are several things
+you can try before you give up in frustration:
+
+=over 4
+
+=item * Solve the balanced text problem from another question in L<perlfaq6>
+
+=item * Try the recursive regex features in Perl 5.10 and later. See L<perlre>
+
+=item * Try defining a grammar using Perl 5.10's C<(?DEFINE)> feature.
+
+=item * Break the problem down into sub-problems instead of trying to use a single regex
+
+=item * Convince everyone not to use XML or HTML in the first place
+
+=back
+
+Good luck!
+
+=head2 I put a regular expression into $/ but it didn't work. What's wrong?
+X<$/, regexes in> X<$INPUT_RECORD_SEPARATOR, regexes in>
+X<$RS, regexes in>
+
+$/ has to be a string. You can use these examples if you really need to
+do this.
+
+If you have File::Stream, this is easy.
+
+ use File::Stream;
+
+ my $stream = File::Stream->new(
+ $filehandle,
+ separator => qr/\s*,\s*/,
+ );
+
+ print "$_\n" while <$stream>;
+
+If you don't have File::Stream, you have to do a little more work.
+
+You can use the four-argument form of sysread to continually add to
+a buffer. After you add to the buffer, you check if you have a
+complete line (using your regular expression).
+
+ local $_ = "";
+ while( sysread FH, $_, 8192, length ) {
+ while( s/^((?s).*?)your_pattern// ) {
+ my $record = $1;
+ # do stuff here.
+ }
+ }
+
+You can do the same thing with foreach and a match using the
+c flag and the \G anchor, if you do not mind your entire file
+being in memory at the end.
+
+ local $_ = "";
+ while( sysread FH, $_, 8192, length ) {
+ foreach my $record ( m/\G((?s).*?)your_pattern/gc ) {
+ # do stuff here.
+ }
+ substr( $_, 0, pos ) = "" if pos;
+ }
+
+
+=head2 How do I substitute case insensitively on the LHS while preserving case on the RHS?
+X<replace, case preserving> X<substitute, case preserving>
+X<substitution, case preserving> X<s, case preserving>
+
+Here's a lovely Perlish solution by Larry Rosler. It exploits
+properties of bitwise xor on ASCII strings.
+
+ $_= "this is a TEsT case";
+
+ $old = 'test';
+ $new = 'success';
+
+ s{(\Q$old\E)}
+ { uc $new | (uc $1 ^ $1) .
+ (uc(substr $1, -1) ^ substr $1, -1) x
+ (length($new) - length $1)
+ }egi;
+
+ print;
+
+And here it is as a subroutine, modeled after the above:
+
+ sub preserve_case($$) {
+ my ($old, $new) = @_;
+ my $mask = uc $old ^ $old;
+
+ uc $new | $mask .
+ substr($mask, -1) x (length($new) - length($old))
+ }
+
+ $string = "this is a TEsT case";
+ $string =~ s/(test)/preserve_case($1, "success")/egi;
+ print "$string\n";
+
+This prints:
+
+ this is a SUcCESS case
+
+As an alternative, to keep the case of the replacement word if it is
+longer than the original, you can use this code, by Jeff Pinyan:
+
+ sub preserve_case {
+ my ($from, $to) = @_;
+ my ($lf, $lt) = map length, @_;
+
+ if ($lt < $lf) { $from = substr $from, 0, $lt }
+ else { $from .= substr $to, $lf }
+
+ return uc $to | ($from ^ uc $from);
+ }
+
+This changes the sentence to "this is a SUcCess case."
+
+Just to show that C programmers can write C in any programming language,
+if you prefer a more C-like solution, the following script makes the
+substitution have the same case, letter by letter, as the original.
+(It also happens to run about 240% slower than the Perlish solution runs.)
+If the substitution has more characters than the string being substituted,
+the case of the last character is used for the rest of the substitution.
+
+ # Original by Nathan Torkington, massaged by Jeffrey Friedl
+ #
+ sub preserve_case($$)
+ {
+ my ($old, $new) = @_;
+ my ($state) = 0; # 0 = no change; 1 = lc; 2 = uc
+ my ($i, $oldlen, $newlen, $c) = (0, length($old), length($new));
+ my ($len) = $oldlen < $newlen ? $oldlen : $newlen;
+
+ for ($i = 0; $i < $len; $i++) {
+ if ($c = substr($old, $i, 1), $c =~ /[\W\d_]/) {
+ $state = 0;
+ } elsif (lc $c eq $c) {
+ substr($new, $i, 1) = lc(substr($new, $i, 1));
+ $state = 1;
+ } else {
+ substr($new, $i, 1) = uc(substr($new, $i, 1));
+ $state = 2;
+ }
+ }
+ # finish up with any remaining new (for when new is longer than old)
+ if ($newlen > $oldlen) {
+ if ($state == 1) {
+ substr($new, $oldlen) = lc(substr($new, $oldlen));
+ } elsif ($state == 2) {
+ substr($new, $oldlen) = uc(substr($new, $oldlen));
+ }
+ }
+ return $new;
+ }
+
+=head2 How can I make C<\w> match national character sets?
+X<\w>
+
+Put C<use locale;> in your script. The \w character class is taken
+from the current locale.
+
+See L<perllocale> for details.
+
+=head2 How can I match a locale-smart version of C</[a-zA-Z]/>?
+X<alpha>
+
+You can use the POSIX character class syntax C</[[:alpha:]]/>
+documented in L<perlre>.
+
+No matter which locale you are in, the alphabetic characters are
+the characters in \w without the digits and the underscore.
+As a regex, that looks like C</[^\W\d_]/>. Its complement,
+the non-alphabetics, is then everything in \W along with
+the digits and the underscore, or C</[\W\d_]/>.
+
+=head2 How can I quote a variable to use in a regex?
+X<regex, escaping> X<regexp, escaping> X<regular expression, escaping>
+
+The Perl parser will expand $variable and @variable references in
+regular expressions unless the delimiter is a single quote. Remember,
+too, that the right-hand side of a C<s///> substitution is considered
+a double-quoted string (see L<perlop> for more details). Remember
+also that any regex special characters will be acted on unless you
+precede the substitution with \Q. Here's an example:
+
+ $string = "Placido P. Octopus";
+ $regex = "P.";
+
+ $string =~ s/$regex/Polyp/;
+ # $string is now "Polypacido P. Octopus"
+
+Because C<.> is special in regular expressions, and can match any
+single character, the regex C<P.> here has matched the <Pl> in the
+original string.
+
+To escape the special meaning of C<.>, we use C<\Q>:
+
+ $string = "Placido P. Octopus";
+ $regex = "P.";
+
+ $string =~ s/\Q$regex/Polyp/;
+ # $string is now "Placido Polyp Octopus"
+
+The use of C<\Q> causes the <.> in the regex to be treated as a
+regular character, so that C<P.> matches a C<P> followed by a dot.
+
+=head2 What is C</o> really for?
+X</o, regular expressions> X<compile, regular expressions>
+
+(contributed by brian d foy)
+
+The C</o> option for regular expressions (documented in L<perlop> and
+L<perlreref>) tells Perl to compile the regular expression only once.
+This is only useful when the pattern contains a variable. Perls 5.6
+and later handle this automatically if the pattern does not change.
+
+Since the match operator C<m//>, the substitution operator C<s///>,
+and the regular expression quoting operator C<qr//> are double-quotish
+constructs, you can interpolate variables into the pattern. See the
+answer to "How can I quote a variable to use in a regex?" for more
+details.
+
+This example takes a regular expression from the argument list and
+prints the lines of input that match it:
+
+ my $pattern = shift @ARGV;
+
+ while( <> ) {
+ print if m/$pattern/;
+ }
+
+Versions of Perl prior to 5.6 would recompile the regular expression
+for each iteration, even if C<$pattern> had not changed. The C</o>
+would prevent this by telling Perl to compile the pattern the first
+time, then reuse that for subsequent iterations:
+
+ my $pattern = shift @ARGV;
+
+ while( <> ) {
+ print if m/$pattern/o; # useful for Perl < 5.6
+ }
+
+In versions 5.6 and later, Perl won't recompile the regular expression
+if the variable hasn't changed, so you probably don't need the C</o>
+option. It doesn't hurt, but it doesn't help either. If you want any
+version of Perl to compile the regular expression only once even if
+the variable changes (thus, only using its initial value), you still
+need the C</o>.
+
+You can watch Perl's regular expression engine at work to verify for
+yourself if Perl is recompiling a regular expression. The C<use re
+'debug'> pragma (comes with Perl 5.005 and later) shows the details.
+With Perls before 5.6, you should see C<re> reporting that its
+compiling the regular expression on each iteration. With Perl 5.6 or
+later, you should only see C<re> report that for the first iteration.
+
+ use re 'debug';
+
+ $regex = 'Perl';
+ foreach ( qw(Perl Java Ruby Python) ) {
+ print STDERR "-" x 73, "\n";
+ print STDERR "Trying $_...\n";
+ print STDERR "\t$_ is good!\n" if m/$regex/;
+ }
+
+=head2 How do I use a regular expression to strip C style comments from a file?
+
+While this actually can be done, it's much harder than you'd think.
+For example, this one-liner
+
+ perl -0777 -pe 's{/\*.*?\*/}{}gs' foo.c
+
+will work in many but not all cases. You see, it's too simple-minded for
+certain kinds of C programs, in particular, those with what appear to be
+comments in quoted strings. For that, you'd need something like this,
+created by Jeffrey Friedl and later modified by Fred Curtis.
+
+ $/ = undef;
+ $_ = <>;
+ s#/\*[^*]*\*+([^/*][^*]*\*+)*/|("(\\.|[^"\\])*"|'(\\.|[^'\\])*'|.[^/"'\\]*)#defined $2 ? $2 : ""#gse;
+ print;
+
+This could, of course, be more legibly written with the C</x> modifier, adding
+whitespace and comments. Here it is expanded, courtesy of Fred Curtis.
+
+ s{
+ /\* ## Start of /* ... */ comment
+ [^*]*\*+ ## Non-* followed by 1-or-more *'s
+ (
+ [^/*][^*]*\*+
+ )* ## 0-or-more things which don't start with /
+ ## but do end with '*'
+ / ## End of /* ... */ comment
+
+ | ## OR various things which aren't comments:
+
+ (
+ " ## Start of " ... " string
+ (
+ \\. ## Escaped char
+ | ## OR
+ [^"\\] ## Non "\
+ )*
+ " ## End of " ... " string
+
+ | ## OR
+
+ ' ## Start of ' ... ' string
+ (
+ \\. ## Escaped char
+ | ## OR
+ [^'\\] ## Non '\
+ )*
+ ' ## End of ' ... ' string
+
+ | ## OR
+
+ . ## Anything other char
+ [^/"'\\]* ## Chars which doesn't start a comment, string or escape
+ )
+ }{defined $2 ? $2 : ""}gxse;
+
+A slight modification also removes C++ comments, possibly spanning multiple lines
+using a continuation character:
+
+ s#/\*[^*]*\*+([^/*][^*]*\*+)*/|//([^\\]|[^\n][\n]?)*?\n|("(\\.|[^"\\])*"|'(\\.|[^'\\])*'|.[^/"'\\]*)#defined $3 ? $3 : ""#gse;
+
+=head2 Can I use Perl regular expressions to match balanced text?
+X<regex, matching balanced test> X<regexp, matching balanced test>
+X<regular expression, matching balanced test> X<possessive> X<PARNO>
+X<Text::Balanced> X<Regexp::Common> X<backtracking> X<recursion>
+
+(contributed by brian d foy)
+
+Your first try should probably be the C<Text::Balanced> module, which
+is in the Perl standard library since Perl 5.8. It has a variety of
+functions to deal with tricky text. The C<Regexp::Common> module can
+also help by providing canned patterns you can use.
+
+As of Perl 5.10, you can match balanced text with regular expressions
+using recursive patterns. Before Perl 5.10, you had to resort to
+various tricks such as using Perl code in C<(??{})> sequences.
+
+Here's an example using a recursive regular expression. The goal is to
+capture all of the text within angle brackets, including the text in
+nested angle brackets. This sample text has two "major" groups: a
+group with one level of nesting and a group with two levels of
+nesting. There are five total groups in angle brackets:
+
+ I have some <brackets in <nested brackets> > and
+ <another group <nested once <nested twice> > >
+ and that's it.
+
+The regular expression to match the balanced text uses two new (to
+Perl 5.10) regular expression features. These are covered in L<perlre>
+and this example is a modified version of one in that documentation.
+
+First, adding the new possessive C<+> to any quantifier finds the
+longest match and does not backtrack. That's important since you want
+to handle any angle brackets through the recursion, not backtracking.
+The group C<< [^<>]++ >> finds one or more non-angle brackets without
+backtracking.
+
+Second, the new C<(?PARNO)> refers to the sub-pattern in the
+particular capture buffer given by C<PARNO>. In the following regex,
+the first capture buffer finds (and remembers) the balanced text, and
+you need that same pattern within the first buffer to get past the
+nested text. That's the recursive part. The C<(?1)> uses the pattern
+in the outer capture buffer as an independent part of the regex.
+
+Putting it all together, you have:
+
+ #!/usr/local/bin/perl5.10.0
+
+ my $string =<<"HERE";
+ I have some <brackets in <nested brackets> > and
+ <another group <nested once <nested twice> > >
+ and that's it.
+ HERE
+
+ my @groups = $string =~ m/
+ ( # start of capture buffer 1
+ < # match an opening angle bracket
+ (?:
+ [^<>]++ # one or more non angle brackets, non backtracking
+ |
+ (?1) # found < or >, so recurse to capture buffer 1
+ )*
+ > # match a closing angle bracket
+ ) # end of capture buffer 1
+ /xg;
+
+ $" = "\n\t";
+ print "Found:\n\t@groups\n";
+
+The output shows that Perl found the two major groups:
+
+ Found:
+ <brackets in <nested brackets> >
+ <another group <nested once <nested twice> > >
+
+With a little extra work, you can get the all of the groups in angle
+brackets even if they are in other angle brackets too. Each time you
+get a balanced match, remove its outer delimiter (that's the one you
+just matched so don't match it again) and add it to a queue of strings
+to process. Keep doing that until you get no matches:
+
+ #!/usr/local/bin/perl5.10.0
+
+ my @queue =<<"HERE";
+ I have some <brackets in <nested brackets> > and
+ <another group <nested once <nested twice> > >
+ and that's it.
+ HERE
+
+ my $regex = qr/
+ ( # start of bracket 1
+ < # match an opening angle bracket
+ (?:
+ [^<>]++ # one or more non angle brackets, non backtracking
+ |
+ (?1) # recurse to bracket 1
+ )*
+ > # match a closing angle bracket
+ ) # end of bracket 1
+ /x;
+
+ $" = "\n\t";
+
+ while( @queue )
+ {
+ my $string = shift @queue;
+
+ my @groups = $string =~ m/$regex/g;
+ print "Found:\n\t@groups\n\n" if @groups;
+
+ unshift @queue, map { s/^<//; s/>$//; $_ } @groups;
+ }
+
+The output shows all of the groups. The outermost matches show up
+first and the nested matches so up later:
+
+ Found:
+ <brackets in <nested brackets> >
+ <another group <nested once <nested twice> > >
+
+ Found:
+ <nested brackets>
+
+ Found:
+ <nested once <nested twice> >
+
+ Found:
+ <nested twice>
+
+=head2 What does it mean that regexes are greedy? How can I get around it?
+X<greedy> X<greediness>
+
+Most people mean that greedy regexes match as much as they can.
+Technically speaking, it's actually the quantifiers (C<?>, C<*>, C<+>,
+C<{}>) that are greedy rather than the whole pattern; Perl prefers local
+greed and immediate gratification to overall greed. To get non-greedy
+versions of the same quantifiers, use (C<??>, C<*?>, C<+?>, C<{}?>).
+
+An example:
+
+ $s1 = $s2 = "I am very very cold";
+ $s1 =~ s/ve.*y //; # I am cold
+ $s2 =~ s/ve.*?y //; # I am very cold
+
+Notice how the second substitution stopped matching as soon as it
+encountered "y ". The C<*?> quantifier effectively tells the regular
+expression engine to find a match as quickly as possible and pass
+control on to whatever is next in line, like you would if you were
+playing hot potato.
+
+=head2 How do I process each word on each line?
+X<word>
+
+Use the split function:
+
+ while (<>) {
+ foreach $word ( split ) {
+ # do something with $word here
+ }
+ }
+
+Note that this isn't really a word in the English sense; it's just
+chunks of consecutive non-whitespace characters.
+
+To work with only alphanumeric sequences (including underscores), you
+might consider
+
+ while (<>) {
+ foreach $word (m/(\w+)/g) {
+ # do something with $word here
+ }
+ }
+
+=head2 How can I print out a word-frequency or line-frequency summary?
+
+To do this, you have to parse out each word in the input stream. We'll
+pretend that by word you mean chunk of alphabetics, hyphens, or
+apostrophes, rather than the non-whitespace chunk idea of a word given
+in the previous question:
+
+ while (<>) {
+ while ( /(\b[^\W_\d][\w'-]+\b)/g ) { # misses "`sheep'"
+ $seen{$1}++;
+ }
+ }
+
+ while ( ($word, $count) = each %seen ) {
+ print "$count $word\n";
+ }
+
+If you wanted to do the same thing for lines, you wouldn't need a
+regular expression:
+
+ while (<>) {
+ $seen{$_}++;
+ }
+
+ while ( ($line, $count) = each %seen ) {
+ print "$count $line";
+ }
+
+If you want these output in a sorted order, see L<perlfaq4>: "How do I
+sort a hash (optionally by value instead of key)?".
+
+=head2 How can I do approximate matching?
+X<match, approximate> X<matching, approximate>
+
+See the module String::Approx available from CPAN.
+
+=head2 How do I efficiently match many regular expressions at once?
+X<regex, efficiency> X<regexp, efficiency>
+X<regular expression, efficiency>
+
+( contributed by brian d foy )
+
+Avoid asking Perl to compile a regular expression every time
+you want to match it. In this example, perl must recompile
+the regular expression for every iteration of the C<foreach>
+loop since it has no way to know what $pattern will be.
+
+ @patterns = qw( foo bar baz );
+
+ LINE: while( <DATA> )
+ {
+ foreach $pattern ( @patterns )
+ {
+ if( /\b$pattern\b/i )
+ {
+ print;
+ next LINE;
+ }
+ }
+ }
+
+The C<qr//> operator showed up in perl 5.005. It compiles a
+regular expression, but doesn't apply it. When you use the
+pre-compiled version of the regex, perl does less work. In
+this example, I inserted a C<map> to turn each pattern into
+its pre-compiled form. The rest of the script is the same,
+but faster.
+
+ @patterns = map { qr/\b$_\b/i } qw( foo bar baz );
+
+ LINE: while( <> )
+ {
+ foreach $pattern ( @patterns )
+ {
+ if( /$pattern/ )
+ {
+ print;
+ next LINE;
+ }
+ }
+ }
+
+In some cases, you may be able to make several patterns into
+a single regular expression. Beware of situations that require
+backtracking though.
+
+ $regex = join '|', qw( foo bar baz );
+
+ LINE: while( <> )
+ {
+ print if /\b(?:$regex)\b/i;
+ }
+
+For more details on regular expression efficiency, see I<Mastering
+Regular Expressions> by Jeffrey Freidl. He explains how regular
+expressions engine work and why some patterns are surprisingly
+inefficient. Once you understand how perl applies regular
+expressions, you can tune them for individual situations.
+
+=head2 Why don't word-boundary searches with C<\b> work for me?
+X<\b>
+
+(contributed by brian d foy)
+
+Ensure that you know what \b really does: it's the boundary between a
+word character, \w, and something that isn't a word character. That
+thing that isn't a word character might be \W, but it can also be the
+start or end of the string.
+
+It's not (not!) the boundary between whitespace and non-whitespace,
+and it's not the stuff between words we use to create sentences.
+
+In regex speak, a word boundary (\b) is a "zero width assertion",
+meaning that it doesn't represent a character in the string, but a
+condition at a certain position.
+
+For the regular expression, /\bPerl\b/, there has to be a word
+boundary before the "P" and after the "l". As long as something other
+than a word character precedes the "P" and succeeds the "l", the
+pattern will match. These strings match /\bPerl\b/.
+
+ "Perl" # no word char before P or after l
+ "Perl " # same as previous (space is not a word char)
+ "'Perl'" # the ' char is not a word char
+ "Perl's" # no word char before P, non-word char after "l"
+
+These strings do not match /\bPerl\b/.
+
+ "Perl_" # _ is a word char!
+ "Perler" # no word char before P, but one after l
+
+You don't have to use \b to match words though. You can look for
+non-word characters surrounded by word characters. These strings
+match the pattern /\b'\b/.
+
+ "don't" # the ' char is surrounded by "n" and "t"
+ "qep'a'" # the ' char is surrounded by "p" and "a"
+
+These strings do not match /\b'\b/.
+
+ "foo'" # there is no word char after non-word '
+
+You can also use the complement of \b, \B, to specify that there
+should not be a word boundary.
+
+In the pattern /\Bam\B/, there must be a word character before the "a"
+and after the "m". These patterns match /\Bam\B/:
+
+ "llama" # "am" surrounded by word chars
+ "Samuel" # same
+
+These strings do not match /\Bam\B/
+
+ "Sam" # no word boundary before "a", but one after "m"
+ "I am Sam" # "am" surrounded by non-word chars
+
+
+=head2 Why does using $&, $`, or $' slow my program down?
+X<$MATCH> X<$&> X<$POSTMATCH> X<$'> X<$PREMATCH> X<$`>
+
+(contributed by Anno Siegel)
+
+Once Perl sees that you need one of these variables anywhere in the
+program, it provides them on each and every pattern match. That means
+that on every pattern match the entire string will be copied, part of it
+to $`, part to $&, and part to $'. Thus the penalty is most severe with
+long strings and patterns that match often. Avoid $&, $', and $` if you
+can, but if you can't, once you've used them at all, use them at will
+because you've already paid the price. Remember that some algorithms
+really appreciate them. As of the 5.005 release, the $& variable is no
+longer "expensive" the way the other two are.
+
+Since Perl 5.6.1 the special variables @- and @+ can functionally replace
+$`, $& and $'. These arrays contain pointers to the beginning and end
+of each match (see perlvar for the full story), so they give you
+essentially the same information, but without the risk of excessive
+string copying.
+
+Perl 5.10 added three specials, C<${^MATCH}>, C<${^PREMATCH}>, and
+C<${^POSTMATCH}> to do the same job but without the global performance
+penalty. Perl 5.10 only sets these variables if you compile or execute the
+regular expression with the C</p> modifier.
+
+=head2 What good is C<\G> in a regular expression?
+X<\G>
+
+You use the C<\G> anchor to start the next match on the same
+string where the last match left off. The regular
+expression engine cannot skip over any characters to find
+the next match with this anchor, so C<\G> is similar to the
+beginning of string anchor, C<^>. The C<\G> anchor is typically
+used with the C<g> flag. It uses the value of C<pos()>
+as the position to start the next match. As the match
+operator makes successive matches, it updates C<pos()> with the
+position of the next character past the last match (or the
+first character of the next match, depending on how you like
+to look at it). Each string has its own C<pos()> value.
+
+Suppose you want to match all of consecutive pairs of digits
+in a string like "1122a44" and stop matching when you
+encounter non-digits. You want to match C<11> and C<22> but
+the letter <a> shows up between C<22> and C<44> and you want
+to stop at C<a>. Simply matching pairs of digits skips over
+the C<a> and still matches C<44>.
+
+ $_ = "1122a44";
+ my @pairs = m/(\d\d)/g; # qw( 11 22 44 )
+
+If you use the C<\G> anchor, you force the match after C<22> to
+start with the C<a>. The regular expression cannot match
+there since it does not find a digit, so the next match
+fails and the match operator returns the pairs it already
+found.
+
+ $_ = "1122a44";
+ my @pairs = m/\G(\d\d)/g; # qw( 11 22 )
+
+You can also use the C<\G> anchor in scalar context. You
+still need the C<g> flag.
+
+ $_ = "1122a44";
+ while( m/\G(\d\d)/g )
+ {
+ print "Found $1\n";
+ }
+
+After the match fails at the letter C<a>, perl resets C<pos()>
+and the next match on the same string starts at the beginning.
+
+ $_ = "1122a44";
+ while( m/\G(\d\d)/g )
+ {
+ print "Found $1\n";
+ }
+
+ print "Found $1 after while" if m/(\d\d)/g; # finds "11"
+
+You can disable C<pos()> resets on fail with the C<c> flag, documented
+in L<perlop> and L<perlreref>. Subsequent matches start where the last
+successful match ended (the value of C<pos()>) even if a match on the
+same string has failed in the meantime. In this case, the match after
+the C<while()> loop starts at the C<a> (where the last match stopped),
+and since it does not use any anchor it can skip over the C<a> to find
+C<44>.
+
+ $_ = "1122a44";
+ while( m/\G(\d\d)/gc )
+ {
+ print "Found $1\n";
+ }
+
+ print "Found $1 after while" if m/(\d\d)/g; # finds "44"
+
+Typically you use the C<\G> anchor with the C<c> flag
+when you want to try a different match if one fails,
+such as in a tokenizer. Jeffrey Friedl offers this example
+which works in 5.004 or later.
+
+ while (<>) {
+ chomp;
+ PARSER: {
+ m/ \G( \d+\b )/gcx && do { print "number: $1\n"; redo; };
+ m/ \G( \w+ )/gcx && do { print "word: $1\n"; redo; };
+ m/ \G( \s+ )/gcx && do { print "space: $1\n"; redo; };
+ m/ \G( [^\w\d]+ )/gcx && do { print "other: $1\n"; redo; };
+ }
+ }
+
+For each line, the C<PARSER> loop first tries to match a series
+of digits followed by a word boundary. This match has to
+start at the place the last match left off (or the beginning
+of the string on the first match). Since C<m/ \G( \d+\b
+)/gcx> uses the C<c> flag, if the string does not match that
+regular expression, perl does not reset pos() and the next
+match starts at the same position to try a different
+pattern.
+
+=head2 Are Perl regexes DFAs or NFAs? Are they POSIX compliant?
+X<DFA> X<NFA> X<POSIX>
+
+While it's true that Perl's regular expressions resemble the DFAs
+(deterministic finite automata) of the egrep(1) program, they are in
+fact implemented as NFAs (non-deterministic finite automata) to allow
+backtracking and backreferencing. And they aren't POSIX-style either,
+because those guarantee worst-case behavior for all cases. (It seems
+that some people prefer guarantees of consistency, even when what's
+guaranteed is slowness.) See the book "Mastering Regular Expressions"
+(from O'Reilly) by Jeffrey Friedl for all the details you could ever
+hope to know on these matters (a full citation appears in
+L<perlfaq2>).
+
+=head2 What's wrong with using grep in a void context?
+X<grep>
+
+The problem is that grep builds a return list, regardless of the context.
+This means you're making Perl go to the trouble of building a list that
+you then just throw away. If the list is large, you waste both time and space.
+If your intent is to iterate over the list, then use a for loop for this
+purpose.
+
+In perls older than 5.8.1, map suffers from this problem as well.
+But since 5.8.1, this has been fixed, and map is context aware - in void
+context, no lists are constructed.
+
+=head2 How can I match strings with multibyte characters?
+X<regex, and multibyte characters> X<regexp, and multibyte characters>
+X<regular expression, and multibyte characters> X<martian> X<encoding, Martian>
+
+Starting from Perl 5.6 Perl has had some level of multibyte character
+support. Perl 5.8 or later is recommended. Supported multibyte
+character repertoires include Unicode, and legacy encodings
+through the Encode module. See L<perluniintro>, L<perlunicode>,
+and L<Encode>.
+
+If you are stuck with older Perls, you can do Unicode with the
+C<Unicode::String> module, and character conversions using the
+C<Unicode::Map8> and C<Unicode::Map> modules. If you are using
+Japanese encodings, you might try using the jperl 5.005_03.
+
+Finally, the following set of approaches was offered by Jeffrey
+Friedl, whose article in issue #5 of The Perl Journal talks about
+this very matter.
+
+Let's suppose you have some weird Martian encoding where pairs of
+ASCII uppercase letters encode single Martian letters (i.e. the two
+bytes "CV" make a single Martian letter, as do the two bytes "SG",
+"VS", "XX", etc.). Other bytes represent single characters, just like
+ASCII.
+
+So, the string of Martian "I am CVSGXX!" uses 12 bytes to encode the
+nine characters 'I', ' ', 'a', 'm', ' ', 'CV', 'SG', 'XX', '!'.
+
+Now, say you want to search for the single character C</GX/>. Perl
+doesn't know about Martian, so it'll find the two bytes "GX" in the "I
+am CVSGXX!" string, even though that character isn't there: it just
+looks like it is because "SG" is next to "XX", but there's no real
+"GX". This is a big problem.
+
+Here are a few ways, all painful, to deal with it:
+
+ # Make sure adjacent "martian" bytes are no longer adjacent.
+ $martian =~ s/([A-Z][A-Z])/ $1 /g;
+
+ print "found GX!\n" if $martian =~ /GX/;
+
+Or like this:
+
+ @chars = $martian =~ m/([A-Z][A-Z]|[^A-Z])/g;
+ # above is conceptually similar to: @chars = $text =~ m/(.)/g;
+ #
+ foreach $char (@chars) {
+ print "found GX!\n", last if $char eq 'GX';
+ }
+
+Or like this:
+
+ while ($martian =~ m/\G([A-Z][A-Z]|.)/gs) { # \G probably unneeded
+ print "found GX!\n", last if $1 eq 'GX';
+ }
+
+Here's another, slightly less painful, way to do it from Benjamin
+Goldberg, who uses a zero-width negative look-behind assertion.
+
+ print "found GX!\n" if $martian =~ m/
+ (?<![A-Z])
+ (?:[A-Z][A-Z])*?
+ GX
+ /x;
+
+This succeeds if the "martian" character GX is in the string, and fails
+otherwise. If you don't like using (?<!), a zero-width negative
+look-behind assertion, you can replace (?<![A-Z]) with (?:^|[^A-Z]).
+
+It does have the drawback of putting the wrong thing in $-[0] and $+[0],
+but this usually can be worked around.
+
+=head2 How do I match a regular expression that's in a variable?
+X<regex, in variable> X<eval> X<regex> X<quotemeta> X<\Q, regex>
+X<\E, regex>, X<qr//>
+
+(contributed by brian d foy)
+
+We don't have to hard-code patterns into the match operator (or
+anything else that works with regular expressions). We can put the
+pattern in a variable for later use.
+
+The match operator is a double quote context, so you can interpolate
+your variable just like a double quoted string. In this case, you
+read the regular expression as user input and store it in C<$regex>.
+Once you have the pattern in C<$regex>, you use that variable in the
+match operator.
+
+ chomp( my $regex = <STDIN> );
+
+ if( $string =~ m/$regex/ ) { ... }
+
+Any regular expression special characters in C<$regex> are still
+special, and the pattern still has to be valid or Perl will complain.
+For instance, in this pattern there is an unpaired parenthesis.
+
+ my $regex = "Unmatched ( paren";
+
+ "Two parens to bind them all" =~ m/$regex/;
+
+When Perl compiles the regular expression, it treats the parenthesis
+as the start of a memory match. When it doesn't find the closing
+parenthesis, it complains:
+
+ Unmatched ( in regex; marked by <-- HERE in m/Unmatched ( <-- HERE paren/ at script line 3.
+
+You can get around this in several ways depending on our situation.
+First, if you don't want any of the characters in the string to be
+special, you can escape them with C<quotemeta> before you use the string.
+
+ chomp( my $regex = <STDIN> );
+ $regex = quotemeta( $regex );
+
+ if( $string =~ m/$regex/ ) { ... }
+
+You can also do this directly in the match operator using the C<\Q>
+and C<\E> sequences. The C<\Q> tells Perl where to start escaping
+special characters, and the C<\E> tells it where to stop (see L<perlop>
+for more details).
+
+ chomp( my $regex = <STDIN> );
+
+ if( $string =~ m/\Q$regex\E/ ) { ... }
+
+Alternately, you can use C<qr//>, the regular expression quote operator (see
+L<perlop> for more details). It quotes and perhaps compiles the pattern,
+and you can apply regular expression flags to the pattern.
+
+ chomp( my $input = <STDIN> );
+
+ my $regex = qr/$input/is;
+
+ $string =~ m/$regex/ # same as m/$input/is;
+
+You might also want to trap any errors by wrapping an C<eval> block
+around the whole thing.
+
+ chomp( my $input = <STDIN> );
+
+ eval {
+ if( $string =~ m/\Q$input\E/ ) { ... }
+ };
+ warn $@ if $@;
+
+Or...
+
+ my $regex = eval { qr/$input/is };
+ if( defined $regex ) {
+ $string =~ m/$regex/;
+ }
+ else {
+ warn $@;
+ }
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq7.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq7.pod
new file mode 100644
index 00000000000..3782351d68e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq7.pod
@@ -0,0 +1,1072 @@
+=head1 NAME
+
+perlfaq7 - General Perl Language Issues
+
+=head1 DESCRIPTION
+
+This section deals with general Perl language issues that don't
+clearly fit into any of the other sections.
+
+=head2 Can I get a BNF/yacc/RE for the Perl language?
+
+There is no BNF, but you can paw your way through the yacc grammar in
+perly.y in the source distribution if you're particularly brave. The
+grammar relies on very smart tokenizing code, so be prepared to
+venture into toke.c as well.
+
+In the words of Chaim Frenkel: "Perl's grammar can not be reduced to BNF.
+The work of parsing perl is distributed between yacc, the lexer, smoke
+and mirrors."
+
+=head2 What are all these $@%&* punctuation signs, and how do I know when to use them?
+
+They are type specifiers, as detailed in L<perldata>:
+
+ $ for scalar values (number, string or reference)
+ @ for arrays
+ % for hashes (associative arrays)
+ & for subroutines (aka functions, procedures, methods)
+ * for all types of that symbol name. In version 4 you used them like
+ pointers, but in modern perls you can just use references.
+
+There are couple of other symbols that you're likely to encounter that aren't
+really type specifiers:
+
+ <> are used for inputting a record from a filehandle.
+ \ takes a reference to something.
+
+Note that <FILE> is I<neither> the type specifier for files
+nor the name of the handle. It is the C<< <> >> operator applied
+to the handle FILE. It reads one line (well, record--see
+L<perlvar/$E<sol>>) from the handle FILE in scalar context, or I<all> lines
+in list context. When performing open, close, or any other operation
+besides C<< <> >> on files, or even when talking about the handle, do
+I<not> use the brackets. These are correct: C<eof(FH)>, C<seek(FH, 0,
+2)> and "copying from STDIN to FILE".
+
+=head2 Do I always/never have to quote my strings or use semicolons and commas?
+
+Normally, a bareword doesn't need to be quoted, but in most cases
+probably should be (and must be under C<use strict>). But a hash key
+consisting of a simple word (that isn't the name of a defined
+subroutine) and the left-hand operand to the C<< => >> operator both
+count as though they were quoted:
+
+ This is like this
+ ------------ ---------------
+ $foo{line} $foo{'line'}
+ bar => stuff 'bar' => stuff
+
+The final semicolon in a block is optional, as is the final comma in a
+list. Good style (see L<perlstyle>) says to put them in except for
+one-liners:
+
+ if ($whoops) { exit 1 }
+ @nums = (1, 2, 3);
+
+ if ($whoops) {
+ exit 1;
+ }
+
+ @lines = (
+ "There Beren came from mountains cold",
+ "And lost he wandered under leaves",
+ );
+
+=head2 How do I skip some return values?
+
+One way is to treat the return values as a list and index into it:
+
+ $dir = (getpwnam($user))[7];
+
+Another way is to use undef as an element on the left-hand-side:
+
+ ($dev, $ino, undef, undef, $uid, $gid) = stat($file);
+
+You can also use a list slice to select only the elements that
+you need:
+
+ ($dev, $ino, $uid, $gid) = ( stat($file) )[0,1,4,5];
+
+=head2 How do I temporarily block warnings?
+
+If you are running Perl 5.6.0 or better, the C<use warnings> pragma
+allows fine control of what warning are produced.
+See L<perllexwarn> for more details.
+
+ {
+ no warnings; # temporarily turn off warnings
+ $a = $b + $c; # I know these might be undef
+ }
+
+Additionally, you can enable and disable categories of warnings.
+You turn off the categories you want to ignore and you can still
+get other categories of warnings. See L<perllexwarn> for the
+complete details, including the category names and hierarchy.
+
+ {
+ no warnings 'uninitialized';
+ $a = $b + $c;
+ }
+
+If you have an older version of Perl, the C<$^W> variable (documented
+in L<perlvar>) controls runtime warnings for a block:
+
+ {
+ local $^W = 0; # temporarily turn off warnings
+ $a = $b + $c; # I know these might be undef
+ }
+
+Note that like all the punctuation variables, you cannot currently
+use my() on C<$^W>, only local().
+
+=head2 What's an extension?
+
+An extension is a way of calling compiled C code from Perl. Reading
+L<perlxstut> is a good place to learn more about extensions.
+
+=head2 Why do Perl operators have different precedence than C operators?
+
+Actually, they don't. All C operators that Perl copies have the same
+precedence in Perl as they do in C. The problem is with operators that C
+doesn't have, especially functions that give a list context to everything
+on their right, eg. print, chmod, exec, and so on. Such functions are
+called "list operators" and appear as such in the precedence table in
+L<perlop>.
+
+A common mistake is to write:
+
+ unlink $file || die "snafu";
+
+This gets interpreted as:
+
+ unlink ($file || die "snafu");
+
+To avoid this problem, either put in extra parentheses or use the
+super low precedence C<or> operator:
+
+ (unlink $file) || die "snafu";
+ unlink $file or die "snafu";
+
+The "English" operators (C<and>, C<or>, C<xor>, and C<not>)
+deliberately have precedence lower than that of list operators for
+just such situations as the one above.
+
+Another operator with surprising precedence is exponentiation. It
+binds more tightly even than unary minus, making C<-2**2> produce a
+negative not a positive four. It is also right-associating, meaning
+that C<2**3**2> is two raised to the ninth power, not eight squared.
+
+Although it has the same precedence as in C, Perl's C<?:> operator
+produces an lvalue. This assigns $x to either $a or $b, depending
+on the trueness of $maybe:
+
+ ($maybe ? $a : $b) = $x;
+
+=head2 How do I declare/create a structure?
+
+In general, you don't "declare" a structure. Just use a (probably
+anonymous) hash reference. See L<perlref> and L<perldsc> for details.
+Here's an example:
+
+ $person = {}; # new anonymous hash
+ $person->{AGE} = 24; # set field AGE to 24
+ $person->{NAME} = "Nat"; # set field NAME to "Nat"
+
+If you're looking for something a bit more rigorous, try L<perltoot>.
+
+=head2 How do I create a module?
+
+(contributed by brian d foy)
+
+L<perlmod>, L<perlmodlib>, L<perlmodstyle> explain modules
+in all the gory details. L<perlnewmod> gives a brief
+overview of the process along with a couple of suggestions
+about style.
+
+If you need to include C code or C library interfaces in
+your module, you'll need h2xs. h2xs will create the module
+distribution structure and the initial interface files
+you'll need. L<perlxs> and L<perlxstut> explain the details.
+
+If you don't need to use C code, other tools such as
+ExtUtils::ModuleMaker and Module::Starter, can help you
+create a skeleton module distribution.
+
+You may also want to see Sam Tregar's "Writing Perl Modules
+for CPAN" ( http://apress.com/book/bookDisplay.html?bID=14 )
+which is the best hands-on guide to creating module
+distributions.
+
+=head2 How do I adopt or take over a module already on CPAN?
+
+(contributed by brian d foy)
+
+The easiest way to take over a module is to have the current
+module maintainer either make you a co-maintainer or transfer
+the module to you.
+
+If you can't reach the author for some reason (e.g. email bounces),
+the PAUSE admins at modules@perl.org can help. The PAUSE admins
+treat each case individually.
+
+=over 4
+
+=item
+
+Get a login for the Perl Authors Upload Server (PAUSE) if you don't
+already have one: http://pause.perl.org
+
+=item
+
+Write to modules@perl.org explaining what you did to contact the
+current maintainer. The PAUSE admins will also try to reach the
+maintainer.
+
+=item
+
+Post a public message in a heavily trafficked site announcing your
+intention to take over the module.
+
+=item
+
+Wait a bit. The PAUSE admins don't want to act too quickly in case
+the current maintainer is on holiday. If there's no response to
+private communication or the public post, a PAUSE admin can transfer
+it to you.
+
+=back
+
+=head2 How do I create a class?
+X<class, creation> X<package>
+
+(contributed by brian d foy)
+
+In Perl, a class is just a package, and methods are just subroutines.
+Perl doesn't get more formal than that and lets you set up the package
+just the way that you like it (that is, it doesn't set up anything for
+you).
+
+The Perl documentation has several tutorials that cover class
+creation, including L<perlboot> (Barnyard Object Oriented Tutorial),
+L<perltoot> (Tom's Object Oriented Tutorial), L<perlbot> (Bag o'
+Object Tricks), and L<perlobj>.
+
+=head2 How can I tell if a variable is tainted?
+
+You can use the tainted() function of the Scalar::Util module, available
+from CPAN (or included with Perl since release 5.8.0).
+See also L<perlsec/"Laundering and Detecting Tainted Data">.
+
+=head2 What's a closure?
+
+Closures are documented in L<perlref>.
+
+I<Closure> is a computer science term with a precise but
+hard-to-explain meaning. Usually, closures are implemented in Perl as
+anonymous subroutines with lasting references to lexical variables
+outside their own scopes. These lexicals magically refer to the
+variables that were around when the subroutine was defined (deep
+binding).
+
+Closures are most often used in programming languages where you can
+have the return value of a function be itself a function, as you can
+in Perl. Note that some languages provide anonymous functions but are
+not capable of providing proper closures: the Python language, for
+example. For more information on closures, check out any textbook on
+functional programming. Scheme is a language that not only supports
+but encourages closures.
+
+Here's a classic non-closure function-generating function:
+
+ sub add_function_generator {
+ return sub { shift() + shift() };
+ }
+
+ $add_sub = add_function_generator();
+ $sum = $add_sub->(4,5); # $sum is 9 now.
+
+The anonymous subroutine returned by add_function_generator() isn't
+technically a closure because it refers to no lexicals outside its own
+scope. Using a closure gives you a I<function template> with some
+customization slots left out to be filled later.
+
+Contrast this with the following make_adder() function, in which the
+returned anonymous function contains a reference to a lexical variable
+outside the scope of that function itself. Such a reference requires
+that Perl return a proper closure, thus locking in for all time the
+value that the lexical had when the function was created.
+
+ sub make_adder {
+ my $addpiece = shift;
+ return sub { shift() + $addpiece };
+ }
+
+ $f1 = make_adder(20);
+ $f2 = make_adder(555);
+
+Now C<&$f1($n)> is always 20 plus whatever $n you pass in, whereas
+C<&$f2($n)> is always 555 plus whatever $n you pass in. The $addpiece
+in the closure sticks around.
+
+Closures are often used for less esoteric purposes. For example, when
+you want to pass in a bit of code into a function:
+
+ my $line;
+ timeout( 30, sub { $line = <STDIN> } );
+
+If the code to execute had been passed in as a string,
+C<< '$line = <STDIN>' >>, there would have been no way for the
+hypothetical timeout() function to access the lexical variable
+$line back in its caller's scope.
+
+Another use for a closure is to make a variable I<private> to a
+named subroutine, e.g. a counter that gets initialized at creation
+time of the sub and can only be modified from within the sub.
+This is sometimes used with a BEGIN block in package files to make
+sure a variable doesn't get meddled with during the lifetime of the
+package:
+
+ BEGIN {
+ my $id = 0;
+ sub next_id { ++$id }
+ }
+
+This is discussed in more detail in L<perlsub>, see the entry on
+I<Persistent Private Variables>.
+
+=head2 What is variable suicide and how can I prevent it?
+
+This problem was fixed in perl 5.004_05, so preventing it means upgrading
+your version of perl. ;)
+
+Variable suicide is when you (temporarily or permanently) lose the value
+of a variable. It is caused by scoping through my() and local()
+interacting with either closures or aliased foreach() iterator variables
+and subroutine arguments. It used to be easy to inadvertently lose a
+variable's value this way, but now it's much harder. Take this code:
+
+ my $f = 'foo';
+ sub T {
+ while ($i++ < 3) { my $f = $f; $f .= "bar"; print $f, "\n" }
+ }
+
+ T;
+ print "Finally $f\n";
+
+If you are experiencing variable suicide, that C<my $f> in the subroutine
+doesn't pick up a fresh copy of the C<$f> whose value is <foo>. The output
+shows that inside the subroutine the value of C<$f> leaks through when it
+shouldn't, as in this output:
+
+ foobar
+ foobarbar
+ foobarbarbar
+ Finally foo
+
+The $f that has "bar" added to it three times should be a new C<$f>
+C<my $f> should create a new lexical variable each time through the loop.
+The expected output is:
+
+ foobar
+ foobar
+ foobar
+ Finally foo
+
+=head2 How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}?
+
+You need to pass references to these objects. See L<perlsub/"Pass by
+Reference"> for this particular question, and L<perlref> for
+information on references.
+
+=over 4
+
+=item Passing Variables and Functions
+
+Regular variables and functions are quite easy to pass: just pass in a
+reference to an existing or anonymous variable or function:
+
+ func( \$some_scalar );
+
+ func( \@some_array );
+ func( [ 1 .. 10 ] );
+
+ func( \%some_hash );
+ func( { this => 10, that => 20 } );
+
+ func( \&some_func );
+ func( sub { $_[0] ** $_[1] } );
+
+=item Passing Filehandles
+
+As of Perl 5.6, you can represent filehandles with scalar variables
+which you treat as any other scalar.
+
+ open my $fh, $filename or die "Cannot open $filename! $!";
+ func( $fh );
+
+ sub func {
+ my $passed_fh = shift;
+
+ my $line = <$passed_fh>;
+ }
+
+Before Perl 5.6, you had to use the C<*FH> or C<\*FH> notations.
+These are "typeglobs"--see L<perldata/"Typeglobs and Filehandles">
+and especially L<perlsub/"Pass by Reference"> for more information.
+
+=item Passing Regexes
+
+Here's an example of how to pass in a string and a regular expression
+for it to match against. You construct the pattern with the C<qr//>
+operator:
+
+ sub compare($$) {
+ my ($val1, $regex) = @_;
+ my $retval = $val1 =~ /$regex/;
+ return $retval;
+ }
+ $match = compare("old McDonald", qr/d.*D/i);
+
+=item Passing Methods
+
+To pass an object method into a subroutine, you can do this:
+
+ call_a_lot(10, $some_obj, "methname")
+ sub call_a_lot {
+ my ($count, $widget, $trick) = @_;
+ for (my $i = 0; $i < $count; $i++) {
+ $widget->$trick();
+ }
+ }
+
+Or, you can use a closure to bundle up the object, its
+method call, and arguments:
+
+ my $whatnot = sub { $some_obj->obfuscate(@args) };
+ func($whatnot);
+ sub func {
+ my $code = shift;
+ &$code();
+ }
+
+You could also investigate the can() method in the UNIVERSAL class
+(part of the standard perl distribution).
+
+=back
+
+=head2 How do I create a static variable?
+
+(contributed by brian d foy)
+
+In Perl 5.10, declare the variable with C<state>. The C<state>
+declaration creates the lexical variable that persists between calls
+to the subroutine:
+
+ sub counter { state $count = 1; $counter++ }
+
+You can fake a static variable by using a lexical variable which goes
+out of scope. In this example, you define the subroutine C<counter>, and
+it uses the lexical variable C<$count>. Since you wrap this in a BEGIN
+block, C<$count> is defined at compile-time, but also goes out of
+scope at the end of the BEGIN block. The BEGIN block also ensures that
+the subroutine and the value it uses is defined at compile-time so the
+subroutine is ready to use just like any other subroutine, and you can
+put this code in the same place as other subroutines in the program
+text (i.e. at the end of the code, typically). The subroutine
+C<counter> still has a reference to the data, and is the only way you
+can access the value (and each time you do, you increment the value).
+The data in chunk of memory defined by C<$count> is private to
+C<counter>.
+
+ BEGIN {
+ my $count = 1;
+ sub counter { $count++ }
+ }
+
+ my $start = counter();
+
+ .... # code that calls counter();
+
+ my $end = counter();
+
+In the previous example, you created a function-private variable
+because only one function remembered its reference. You could define
+multiple functions while the variable is in scope, and each function
+can share the "private" variable. It's not really "static" because you
+can access it outside the function while the lexical variable is in
+scope, and even create references to it. In this example,
+C<increment_count> and C<return_count> share the variable. One
+function adds to the value and the other simply returns the value.
+They can both access C<$count>, and since it has gone out of scope,
+there is no other way to access it.
+
+ BEGIN {
+ my $count = 1;
+ sub increment_count { $count++ }
+ sub return_count { $count }
+ }
+
+To declare a file-private variable, you still use a lexical variable.
+A file is also a scope, so a lexical variable defined in the file
+cannot be seen from any other file.
+
+See L<perlsub/"Persistent Private Variables"> for more information.
+The discussion of closures in L<perlref> may help you even though we
+did not use anonymous subroutines in this answer. See
+L<perlsub/"Persistent Private Variables"> for details.
+
+=head2 What's the difference between dynamic and lexical (static) scoping? Between local() and my()?
+
+C<local($x)> saves away the old value of the global variable C<$x>
+and assigns a new value for the duration of the subroutine I<which is
+visible in other functions called from that subroutine>. This is done
+at run-time, so is called dynamic scoping. local() always affects global
+variables, also called package variables or dynamic variables.
+
+C<my($x)> creates a new variable that is only visible in the current
+subroutine. This is done at compile-time, so it is called lexical or
+static scoping. my() always affects private variables, also called
+lexical variables or (improperly) static(ly scoped) variables.
+
+For instance:
+
+ sub visible {
+ print "var has value $var\n";
+ }
+
+ sub dynamic {
+ local $var = 'local'; # new temporary value for the still-global
+ visible(); # variable called $var
+ }
+
+ sub lexical {
+ my $var = 'private'; # new private variable, $var
+ visible(); # (invisible outside of sub scope)
+ }
+
+ $var = 'global';
+
+ visible(); # prints global
+ dynamic(); # prints local
+ lexical(); # prints global
+
+Notice how at no point does the value "private" get printed. That's
+because $var only has that value within the block of the lexical()
+function, and it is hidden from called subroutine.
+
+In summary, local() doesn't make what you think of as private, local
+variables. It gives a global variable a temporary value. my() is
+what you're looking for if you want private variables.
+
+See L<perlsub/"Private Variables via my()"> and
+L<perlsub/"Temporary Values via local()"> for excruciating details.
+
+=head2 How can I access a dynamic variable while a similarly named lexical is in scope?
+
+If you know your package, you can just mention it explicitly, as in
+$Some_Pack::var. Note that the notation $::var is B<not> the dynamic $var
+in the current package, but rather the one in the "main" package, as
+though you had written $main::var.
+
+ use vars '$var';
+ local $var = "global";
+ my $var = "lexical";
+
+ print "lexical is $var\n";
+ print "global is $main::var\n";
+
+Alternatively you can use the compiler directive our() to bring a
+dynamic variable into the current lexical scope.
+
+ require 5.006; # our() did not exist before 5.6
+ use vars '$var';
+
+ local $var = "global";
+ my $var = "lexical";
+
+ print "lexical is $var\n";
+
+ {
+ our $var;
+ print "global is $var\n";
+ }
+
+=head2 What's the difference between deep and shallow binding?
+
+In deep binding, lexical variables mentioned in anonymous subroutines
+are the same ones that were in scope when the subroutine was created.
+In shallow binding, they are whichever variables with the same names
+happen to be in scope when the subroutine is called. Perl always uses
+deep binding of lexical variables (i.e., those created with my()).
+However, dynamic variables (aka global, local, or package variables)
+are effectively shallowly bound. Consider this just one more reason
+not to use them. See the answer to L<"What's a closure?">.
+
+=head2 Why doesn't "my($foo) = E<lt>FILEE<gt>;" work right?
+
+C<my()> and C<local()> give list context to the right hand side
+of C<=>. The <FH> read operation, like so many of Perl's
+functions and operators, can tell which context it was called in and
+behaves appropriately. In general, the scalar() function can help.
+This function does nothing to the data itself (contrary to popular myth)
+but rather tells its argument to behave in whatever its scalar fashion is.
+If that function doesn't have a defined scalar behavior, this of course
+doesn't help you (such as with sort()).
+
+To enforce scalar context in this particular case, however, you need
+merely omit the parentheses:
+
+ local($foo) = <FILE>; # WRONG
+ local($foo) = scalar(<FILE>); # ok
+ local $foo = <FILE>; # right
+
+You should probably be using lexical variables anyway, although the
+issue is the same here:
+
+ my($foo) = <FILE>; # WRONG
+ my $foo = <FILE>; # right
+
+=head2 How do I redefine a builtin function, operator, or method?
+
+Why do you want to do that? :-)
+
+If you want to override a predefined function, such as open(),
+then you'll have to import the new definition from a different
+module. See L<perlsub/"Overriding Built-in Functions">. There's
+also an example in L<perltoot/"Class::Template">.
+
+If you want to overload a Perl operator, such as C<+> or C<**>,
+then you'll want to use the C<use overload> pragma, documented
+in L<overload>.
+
+If you're talking about obscuring method calls in parent classes,
+see L<perltoot/"Overridden Methods">.
+
+=head2 What's the difference between calling a function as &foo and foo()?
+
+(contributed by brian d foy)
+
+Calling a subroutine as C<&foo> with no trailing parentheses ignores
+the prototype of C<foo> and passes it the current value of the argument
+list, C<@_>. Here's an example; the C<bar> subroutine calls C<&foo>,
+which prints its arguments list:
+
+ sub bar { &foo }
+
+ sub foo { print "Args in foo are: @_\n" }
+
+ bar( qw( a b c ) );
+
+When you call C<bar> with arguments, you see that C<foo> got the same C<@_>:
+
+ Args in foo are: a b c
+
+Calling the subroutine with trailing parentheses, with or without arguments,
+does not use the current C<@_> and respects the subroutine prototype. Changing
+the example to put parentheses after the call to C<foo> changes the program:
+
+ sub bar { &foo() }
+
+ sub foo { print "Args in foo are: @_\n" }
+
+ bar( qw( a b c ) );
+
+Now the output shows that C<foo> doesn't get the C<@_> from its caller.
+
+ Args in foo are:
+
+The main use of the C<@_> pass-through feature is to write subroutines
+whose main job it is to call other subroutines for you. For further
+details, see L<perlsub>.
+
+=head2 How do I create a switch or case statement?
+
+In Perl 5.10, use the C<given-when> construct described in L<perlsyn>:
+
+ use 5.010;
+
+ given ( $string ) {
+ when( 'Fred' ) { say "I found Fred!" }
+ when( 'Barney' ) { say "I found Barney!" }
+ when( /Bamm-?Bamm/ ) { say "I found Bamm-Bamm!" }
+ default { say "I don't recognize the name!" }
+ };
+
+If one wants to use pure Perl and to be compatible with Perl versions
+prior to 5.10, the general answer is to use C<if-elsif-else>:
+
+ for ($variable_to_test) {
+ if (/pat1/) { } # do something
+ elsif (/pat2/) { } # do something else
+ elsif (/pat3/) { } # do something else
+ else { } # default
+ }
+
+Here's a simple example of a switch based on pattern matching,
+lined up in a way to make it look more like a switch statement.
+We'll do a multiway conditional based on the type of reference stored
+in $whatchamacallit:
+
+ SWITCH: for (ref $whatchamacallit) {
+
+ /^$/ && die "not a reference";
+
+ /SCALAR/ && do {
+ print_scalar($$ref);
+ last SWITCH;
+ };
+
+ /ARRAY/ && do {
+ print_array(@$ref);
+ last SWITCH;
+ };
+
+ /HASH/ && do {
+ print_hash(%$ref);
+ last SWITCH;
+ };
+
+ /CODE/ && do {
+ warn "can't print function ref";
+ last SWITCH;
+ };
+
+ # DEFAULT
+
+ warn "User defined type skipped";
+
+ }
+
+See L<perlsyn> for other examples in this style.
+
+Sometimes you should change the positions of the constant and the variable.
+For example, let's say you wanted to test which of many answers you were
+given, but in a case-insensitive way that also allows abbreviations.
+You can use the following technique if the strings all start with
+different characters or if you want to arrange the matches so that
+one takes precedence over another, as C<"SEND"> has precedence over
+C<"STOP"> here:
+
+ chomp($answer = <>);
+ if ("SEND" =~ /^\Q$answer/i) { print "Action is send\n" }
+ elsif ("STOP" =~ /^\Q$answer/i) { print "Action is stop\n" }
+ elsif ("ABORT" =~ /^\Q$answer/i) { print "Action is abort\n" }
+ elsif ("LIST" =~ /^\Q$answer/i) { print "Action is list\n" }
+ elsif ("EDIT" =~ /^\Q$answer/i) { print "Action is edit\n" }
+
+A totally different approach is to create a hash of function references.
+
+ my %commands = (
+ "happy" => \&joy,
+ "sad", => \&sullen,
+ "done" => sub { die "See ya!" },
+ "mad" => \&angry,
+ );
+
+ print "How are you? ";
+ chomp($string = <STDIN>);
+ if ($commands{$string}) {
+ $commands{$string}->();
+ } else {
+ print "No such command: $string\n";
+ }
+
+Starting from Perl 5.8, a source filter module, C<Switch>, can also be
+used to get switch and case. Its use is now discouraged, because it's
+not fully compatible with the native switch of Perl 5.10, and because,
+as it's implemented as a source filter, it doesn't always work as intended
+when complex syntax is involved.
+
+=head2 How can I catch accesses to undefined variables, functions, or methods?
+
+The AUTOLOAD method, discussed in L<perlsub/"Autoloading"> and
+L<perltoot/"AUTOLOAD: Proxy Methods">, lets you capture calls to
+undefined functions and methods.
+
+When it comes to undefined variables that would trigger a warning
+under C<use warnings>, you can promote the warning to an error.
+
+ use warnings FATAL => qw(uninitialized);
+
+=head2 Why can't a method included in this same file be found?
+
+Some possible reasons: your inheritance is getting confused, you've
+misspelled the method name, or the object is of the wrong type. Check
+out L<perltoot> for details about any of the above cases. You may
+also use C<print ref($object)> to find out the class C<$object> was
+blessed into.
+
+Another possible reason for problems is because you've used the
+indirect object syntax (eg, C<find Guru "Samy">) on a class name
+before Perl has seen that such a package exists. It's wisest to make
+sure your packages are all defined before you start using them, which
+will be taken care of if you use the C<use> statement instead of
+C<require>. If not, make sure to use arrow notation (eg.,
+C<< Guru->find("Samy") >>) instead. Object notation is explained in
+L<perlobj>.
+
+Make sure to read about creating modules in L<perlmod> and
+the perils of indirect objects in L<perlobj/"Method Invocation">.
+
+=head2 How can I find out my current or calling package?
+
+(contributed by brian d foy)
+
+To find the package you are currently in, use the special literal
+C<__PACKAGE__>, as documented in L<perldata>. You can only use the
+special literals as separate tokens, so you can't interpolate them
+into strings like you can with variables:
+
+ my $current_package = __PACKAGE__;
+ print "I am in package $current_package\n";
+
+If you want to find the package calling your code, perhaps to give better
+diagnostics as C<Carp> does, use the C<caller> built-in:
+
+ sub foo {
+ my @args = ...;
+ my( $package, $filename, $line ) = caller;
+
+ print "I was called from package $package\n";
+ );
+
+By default, your program starts in package C<main>, so you should
+always be in some package unless someone uses the C<package> built-in
+with no namespace. See the C<package> entry in L<perlfunc> for the
+details of empty packages.
+
+This is different from finding out the package an object is blessed
+into, which might not be the current package. For that, use C<blessed>
+from C<Scalar::Util>, part of the Standard Library since Perl 5.8:
+
+ use Scalar::Util qw(blessed);
+ my $object_package = blessed( $object );
+
+Most of the time, you shouldn't care what package an object is blessed
+into, however, as long as it claims to inherit from that class:
+
+ my $is_right_class = eval { $object->isa( $package ) }; # true or false
+
+And, with Perl 5.10 and later, you don't have to check for an
+inheritance to see if the object can handle a role. For that, you can
+use C<DOES>, which comes from C<UNIVERSAL>:
+
+ my $class_does_it = eval { $object->DOES( $role ) }; # true or false
+
+You can safely replace C<isa> with C<DOES> (although the converse is not true).
+
+=head2 How can I comment out a large block of Perl code?
+
+(contributed by brian d foy)
+
+The quick-and-dirty way to comment out more than one line of Perl is
+to surround those lines with Pod directives. You have to put these
+directives at the beginning of the line and somewhere where Perl
+expects a new statement (so not in the middle of statements like the #
+comments). You end the comment with C<=cut>, ending the Pod section:
+
+ =pod
+
+ my $object = NotGonnaHappen->new();
+
+ ignored_sub();
+
+ $wont_be_assigned = 37;
+
+ =cut
+
+The quick-and-dirty method only works well when you don't plan to
+leave the commented code in the source. If a Pod parser comes along,
+you're multiline comment is going to show up in the Pod translation.
+A better way hides it from Pod parsers as well.
+
+The C<=begin> directive can mark a section for a particular purpose.
+If the Pod parser doesn't want to handle it, it just ignores it. Label
+the comments with C<comment>. End the comment using C<=end> with the
+same label. You still need the C<=cut> to go back to Perl code from
+the Pod comment:
+
+ =begin comment
+
+ my $object = NotGonnaHappen->new();
+
+ ignored_sub();
+
+ $wont_be_assigned = 37;
+
+ =end comment
+
+ =cut
+
+For more information on Pod, check out L<perlpod> and L<perlpodspec>.
+
+=head2 How do I clear a package?
+
+Use this code, provided by Mark-Jason Dominus:
+
+ sub scrub_package {
+ no strict 'refs';
+ my $pack = shift;
+ die "Shouldn't delete main package"
+ if $pack eq "" || $pack eq "main";
+ my $stash = *{$pack . '::'}{HASH};
+ my $name;
+ foreach $name (keys %$stash) {
+ my $fullname = $pack . '::' . $name;
+ # Get rid of everything with that name.
+ undef $$fullname;
+ undef @$fullname;
+ undef %$fullname;
+ undef &$fullname;
+ undef *$fullname;
+ }
+ }
+
+Or, if you're using a recent release of Perl, you can
+just use the Symbol::delete_package() function instead.
+
+=head2 How can I use a variable as a variable name?
+
+Beginners often think they want to have a variable contain the name
+of a variable.
+
+ $fred = 23;
+ $varname = "fred";
+ ++$$varname; # $fred now 24
+
+This works I<sometimes>, but it is a very bad idea for two reasons.
+
+The first reason is that this technique I<only works on global
+variables>. That means that if $fred is a lexical variable created
+with my() in the above example, the code wouldn't work at all: you'd
+accidentally access the global and skip right over the private lexical
+altogether. Global variables are bad because they can easily collide
+accidentally and in general make for non-scalable and confusing code.
+
+Symbolic references are forbidden under the C<use strict> pragma.
+They are not true references and consequently are not reference counted
+or garbage collected.
+
+The other reason why using a variable to hold the name of another
+variable is a bad idea is that the question often stems from a lack of
+understanding of Perl data structures, particularly hashes. By using
+symbolic references, you are just using the package's symbol-table hash
+(like C<%main::>) instead of a user-defined hash. The solution is to
+use your own hash or a real reference instead.
+
+ $USER_VARS{"fred"} = 23;
+ $varname = "fred";
+ $USER_VARS{$varname}++; # not $$varname++
+
+There we're using the %USER_VARS hash instead of symbolic references.
+Sometimes this comes up in reading strings from the user with variable
+references and wanting to expand them to the values of your perl
+program's variables. This is also a bad idea because it conflates the
+program-addressable namespace and the user-addressable one. Instead of
+reading a string and expanding it to the actual contents of your program's
+own variables:
+
+ $str = 'this has a $fred and $barney in it';
+ $str =~ s/(\$\w+)/$1/eeg; # need double eval
+
+it would be better to keep a hash around like %USER_VARS and have
+variable references actually refer to entries in that hash:
+
+ $str =~ s/\$(\w+)/$USER_VARS{$1}/g; # no /e here at all
+
+That's faster, cleaner, and safer than the previous approach. Of course,
+you don't need to use a dollar sign. You could use your own scheme to
+make it less confusing, like bracketed percent symbols, etc.
+
+ $str = 'this has a %fred% and %barney% in it';
+ $str =~ s/%(\w+)%/$USER_VARS{$1}/g; # no /e here at all
+
+Another reason that folks sometimes think they want a variable to
+contain the name of a variable is because they don't know how to build
+proper data structures using hashes. For example, let's say they
+wanted two hashes in their program: %fred and %barney, and that they
+wanted to use another scalar variable to refer to those by name.
+
+ $name = "fred";
+ $$name{WIFE} = "wilma"; # set %fred
+
+ $name = "barney";
+ $$name{WIFE} = "betty"; # set %barney
+
+This is still a symbolic reference, and is still saddled with the
+problems enumerated above. It would be far better to write:
+
+ $folks{"fred"}{WIFE} = "wilma";
+ $folks{"barney"}{WIFE} = "betty";
+
+And just use a multilevel hash to start with.
+
+The only times that you absolutely I<must> use symbolic references are
+when you really must refer to the symbol table. This may be because it's
+something that can't take a real reference to, such as a format name.
+Doing so may also be important for method calls, since these always go
+through the symbol table for resolution.
+
+In those cases, you would turn off C<strict 'refs'> temporarily so you
+can play around with the symbol table. For example:
+
+ @colors = qw(red blue green yellow orange purple violet);
+ for my $name (@colors) {
+ no strict 'refs'; # renege for the block
+ *$name = sub { "<FONT COLOR='$name'>@_</FONT>" };
+ }
+
+All those functions (red(), blue(), green(), etc.) appear to be separate,
+but the real code in the closure actually was compiled only once.
+
+So, sometimes you might want to use symbolic references to directly
+manipulate the symbol table. This doesn't matter for formats, handles, and
+subroutines, because they are always global--you can't use my() on them.
+For scalars, arrays, and hashes, though--and usually for subroutines--
+you probably only want to use hard references.
+
+=head2 What does "bad interpreter" mean?
+
+(contributed by brian d foy)
+
+The "bad interpreter" message comes from the shell, not perl. The
+actual message may vary depending on your platform, shell, and locale
+settings.
+
+If you see "bad interpreter - no such file or directory", the first
+line in your perl script (the "shebang" line) does not contain the
+right path to perl (or any other program capable of running scripts).
+Sometimes this happens when you move the script from one machine to
+another and each machine has a different path to perl--/usr/bin/perl
+versus /usr/local/bin/perl for instance. It may also indicate
+that the source machine has CRLF line terminators and the
+destination machine has LF only: the shell tries to find
+/usr/bin/perl<CR>, but can't.
+
+If you see "bad interpreter: Permission denied", you need to make your
+script executable.
+
+In either case, you should still be able to run the scripts with perl
+explicitly:
+
+ % perl script.pl
+
+If you get a message like "perl: command not found", perl is not in
+your PATH, which might also mean that the location of perl is not
+where you expect it so you need to adjust your shebang line.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod
new file mode 100644
index 00000000000..08a5b038b45
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod
@@ -0,0 +1,1416 @@
+=head1 NAME
+
+perlfaq8 - System Interaction
+
+=head1 DESCRIPTION
+
+This section of the Perl FAQ covers questions involving operating
+system interaction. Topics include interprocess communication (IPC),
+control over the user-interface (keyboard, screen and pointing
+devices), and most anything else not related to data manipulation.
+
+Read the FAQs and documentation specific to the port of perl to your
+operating system (eg, L<perlvms>, L<perlplan9>, ...). These should
+contain more detailed information on the vagaries of your perl.
+
+=head2 How do I find out which operating system I'm running under?
+
+The C<$^O> variable (C<$OSNAME> if you use C<English>) contains an
+indication of the name of the operating system (not its release
+number) that your perl binary was built for.
+
+=head2 How come exec() doesn't return?
+X<exec> X<system> X<fork> X<open> X<pipe>
+
+(contributed by brian d foy)
+
+The C<exec> function's job is to turn your process into another
+command and never to return. If that's not what you want to do, don't
+use C<exec>. :)
+
+If you want to run an external command and still keep your Perl process
+going, look at a piped C<open>, C<fork>, or C<system>.
+
+=head2 How do I do fancy stuff with the keyboard/screen/mouse?
+
+How you access/control keyboards, screens, and pointing devices
+("mice") is system-dependent. Try the following modules:
+
+=over 4
+
+=item Keyboard
+
+ Term::Cap Standard perl distribution
+ Term::ReadKey CPAN
+ Term::ReadLine::Gnu CPAN
+ Term::ReadLine::Perl CPAN
+ Term::Screen CPAN
+
+=item Screen
+
+ Term::Cap Standard perl distribution
+ Curses CPAN
+ Term::ANSIColor CPAN
+
+=item Mouse
+
+ Tk CPAN
+
+=back
+
+Some of these specific cases are shown as examples in other answers
+in this section of the perlfaq.
+
+=head2 How do I print something out in color?
+
+In general, you don't, because you don't know whether
+the recipient has a color-aware display device. If you
+know that they have an ANSI terminal that understands
+color, you can use the C<Term::ANSIColor> module from CPAN:
+
+ use Term::ANSIColor;
+ print color("red"), "Stop!\n", color("reset");
+ print color("green"), "Go!\n", color("reset");
+
+Or like this:
+
+ use Term::ANSIColor qw(:constants);
+ print RED, "Stop!\n", RESET;
+ print GREEN, "Go!\n", RESET;
+
+=head2 How do I read just one key without waiting for a return key?
+
+Controlling input buffering is a remarkably system-dependent matter.
+On many systems, you can just use the B<stty> command as shown in
+L<perlfunc/getc>, but as you see, that's already getting you into
+portability snags.
+
+ open(TTY, "+</dev/tty") or die "no tty: $!";
+ system "stty cbreak </dev/tty >/dev/tty 2>&1";
+ $key = getc(TTY); # perhaps this works
+ # OR ELSE
+ sysread(TTY, $key, 1); # probably this does
+ system "stty -cbreak </dev/tty >/dev/tty 2>&1";
+
+The C<Term::ReadKey> module from CPAN offers an easy-to-use interface that
+should be more efficient than shelling out to B<stty> for each key.
+It even includes limited support for Windows.
+
+ use Term::ReadKey;
+ ReadMode('cbreak');
+ $key = ReadKey(0);
+ ReadMode('normal');
+
+However, using the code requires that you have a working C compiler
+and can use it to build and install a CPAN module. Here's a solution
+using the standard C<POSIX> module, which is already on your system
+(assuming your system supports POSIX).
+
+ use HotKey;
+ $key = readkey();
+
+And here's the C<HotKey> module, which hides the somewhat mystifying calls
+to manipulate the POSIX termios structures.
+
+ # HotKey.pm
+ package HotKey;
+
+ @ISA = qw(Exporter);
+ @EXPORT = qw(cbreak cooked readkey);
+
+ use strict;
+ use POSIX qw(:termios_h);
+ my ($term, $oterm, $echo, $noecho, $fd_stdin);
+
+ $fd_stdin = fileno(STDIN);
+ $term = POSIX::Termios->new();
+ $term->getattr($fd_stdin);
+ $oterm = $term->getlflag();
+
+ $echo = ECHO | ECHOK | ICANON;
+ $noecho = $oterm & ~$echo;
+
+ sub cbreak {
+ $term->setlflag($noecho); # ok, so i don't want echo either
+ $term->setcc(VTIME, 1);
+ $term->setattr($fd_stdin, TCSANOW);
+ }
+
+ sub cooked {
+ $term->setlflag($oterm);
+ $term->setcc(VTIME, 0);
+ $term->setattr($fd_stdin, TCSANOW);
+ }
+
+ sub readkey {
+ my $key = '';
+ cbreak();
+ sysread(STDIN, $key, 1);
+ cooked();
+ return $key;
+ }
+
+ END { cooked() }
+
+ 1;
+
+=head2 How do I check whether input is ready on the keyboard?
+
+The easiest way to do this is to read a key in nonblocking mode with the
+C<Term::ReadKey> module from CPAN, passing it an argument of -1 to indicate
+not to block:
+
+ use Term::ReadKey;
+
+ ReadMode('cbreak');
+
+ if (defined ($char = ReadKey(-1)) ) {
+ # input was waiting and it was $char
+ } else {
+ # no input was waiting
+ }
+
+ ReadMode('normal'); # restore normal tty settings
+
+=head2 How do I clear the screen?
+
+(contributed by brian d foy)
+
+To clear the screen, you just have to print the special sequence
+that tells the terminal to clear the screen. Once you have that
+sequence, output it when you want to clear the screen.
+
+You can use the C<Term::ANSIScreen> module to get the special
+sequence. Import the C<cls> function (or the C<:screen> tag):
+
+ use Term::ANSIScreen qw(cls);
+ my $clear_screen = cls();
+
+ print $clear_screen;
+
+The C<Term::Cap> module can also get the special sequence if you want
+to deal with the low-level details of terminal control. The C<Tputs>
+method returns the string for the given capability:
+
+ use Term::Cap;
+
+ $terminal = Term::Cap->Tgetent( { OSPEED => 9600 } );
+ $clear_string = $terminal->Tputs('cl');
+
+ print $clear_screen;
+
+On Windows, you can use the C<Win32::Console> module. After creating
+an object for the output filehandle you want to affect, call the
+C<Cls> method:
+
+ Win32::Console;
+
+ $OUT = Win32::Console->new(STD_OUTPUT_HANDLE);
+ my $clear_string = $OUT->Cls;
+
+ print $clear_screen;
+
+If you have a command-line program that does the job, you can call
+it in backticks to capture whatever it outputs so you can use it
+later:
+
+ $clear_string = `clear`;
+
+ print $clear_string;
+
+=head2 How do I get the screen size?
+
+If you have C<Term::ReadKey> module installed from CPAN,
+you can use it to fetch the width and height in characters
+and in pixels:
+
+ use Term::ReadKey;
+ ($wchar, $hchar, $wpixels, $hpixels) = GetTerminalSize();
+
+This is more portable than the raw C<ioctl>, but not as
+illustrative:
+
+ require 'sys/ioctl.ph';
+ die "no TIOCGWINSZ " unless defined &TIOCGWINSZ;
+ open(TTY, "+</dev/tty") or die "No tty: $!";
+ unless (ioctl(TTY, &TIOCGWINSZ, $winsize='')) {
+ die sprintf "$0: ioctl TIOCGWINSZ (%08x: $!)\n", &TIOCGWINSZ;
+ }
+ ($row, $col, $xpixel, $ypixel) = unpack('S4', $winsize);
+ print "(row,col) = ($row,$col)";
+ print " (xpixel,ypixel) = ($xpixel,$ypixel)" if $xpixel || $ypixel;
+ print "\n";
+
+=head2 How do I ask the user for a password?
+
+(This question has nothing to do with the web. See a different
+FAQ for that.)
+
+There's an example of this in L<perlfunc/crypt>). First, you put the
+terminal into "no echo" mode, then just read the password normally.
+You may do this with an old-style C<ioctl()> function, POSIX terminal
+control (see L<POSIX> or its documentation the Camel Book), or a call
+to the B<stty> program, with varying degrees of portability.
+
+You can also do this for most systems using the C<Term::ReadKey> module
+from CPAN, which is easier to use and in theory more portable.
+
+ use Term::ReadKey;
+
+ ReadMode('noecho');
+ $password = ReadLine(0);
+
+=head2 How do I read and write the serial port?
+
+This depends on which operating system your program is running on. In
+the case of Unix, the serial ports will be accessible through files in
+/dev; on other systems, device names will doubtless differ.
+Several problem areas common to all device interaction are the
+following:
+
+=over 4
+
+=item lockfiles
+
+Your system may use lockfiles to control multiple access. Make sure
+you follow the correct protocol. Unpredictable behavior can result
+from multiple processes reading from one device.
+
+=item open mode
+
+If you expect to use both read and write operations on the device,
+you'll have to open it for update (see L<perlfunc/"open"> for
+details). You may wish to open it without running the risk of
+blocking by using C<sysopen()> and C<O_RDWR|O_NDELAY|O_NOCTTY> from the
+C<Fcntl> module (part of the standard perl distribution). See
+L<perlfunc/"sysopen"> for more on this approach.
+
+=item end of line
+
+Some devices will be expecting a "\r" at the end of each line rather
+than a "\n". In some ports of perl, "\r" and "\n" are different from
+their usual (Unix) ASCII values of "\012" and "\015". You may have to
+give the numeric values you want directly, using octal ("\015"), hex
+("0x0D"), or as a control-character specification ("\cM").
+
+ print DEV "atv1\012"; # wrong, for some devices
+ print DEV "atv1\015"; # right, for some devices
+
+Even though with normal text files a "\n" will do the trick, there is
+still no unified scheme for terminating a line that is portable
+between Unix, DOS/Win, and Macintosh, except to terminate I<ALL> line
+ends with "\015\012", and strip what you don't need from the output.
+This applies especially to socket I/O and autoflushing, discussed
+next.
+
+=item flushing output
+
+If you expect characters to get to your device when you C<print()> them,
+you'll want to autoflush that filehandle. You can use C<select()>
+and the C<$|> variable to control autoflushing (see L<perlvar/$E<verbar>>
+and L<perlfunc/select>, or L<perlfaq5>, "How do I flush/unbuffer an
+output filehandle? Why must I do this?"):
+
+ $oldh = select(DEV);
+ $| = 1;
+ select($oldh);
+
+You'll also see code that does this without a temporary variable, as in
+
+ select((select(DEV), $| = 1)[0]);
+
+Or if you don't mind pulling in a few thousand lines
+of code just because you're afraid of a little C<$|> variable:
+
+ use IO::Handle;
+ DEV->autoflush(1);
+
+As mentioned in the previous item, this still doesn't work when using
+socket I/O between Unix and Macintosh. You'll need to hard code your
+line terminators, in that case.
+
+=item non-blocking input
+
+If you are doing a blocking C<read()> or C<sysread()>, you'll have to
+arrange for an alarm handler to provide a timeout (see
+L<perlfunc/alarm>). If you have a non-blocking open, you'll likely
+have a non-blocking read, which means you may have to use a 4-arg
+C<select()> to determine whether I/O is ready on that device (see
+L<perlfunc/"select">.
+
+=back
+
+While trying to read from his caller-id box, the notorious Jamie
+Zawinski C<< <jwz@netscape.com> >>, after much gnashing of teeth and
+fighting with C<sysread>, C<sysopen>, POSIX's C<tcgetattr> business,
+and various other functions that go bump in the night, finally came up
+with this:
+
+ sub open_modem {
+ use IPC::Open2;
+ my $stty = `/bin/stty -g`;
+ open2( \*MODEM_IN, \*MODEM_OUT, "cu -l$modem_device -s2400 2>&1");
+ # starting cu hoses /dev/tty's stty settings, even when it has
+ # been opened on a pipe...
+ system("/bin/stty $stty");
+ $_ = <MODEM_IN>;
+ chomp;
+ if ( !m/^Connected/ ) {
+ print STDERR "$0: cu printed `$_' instead of `Connected'\n";
+ }
+ }
+
+=head2 How do I decode encrypted password files?
+
+You spend lots and lots of money on dedicated hardware, but this is
+bound to get you talked about.
+
+Seriously, you can't if they are Unix password files--the Unix
+password system employs one-way encryption. It's more like hashing
+than encryption. The best you can do is check whether something else
+hashes to the same string. You can't turn a hash back into the
+original string. Programs like Crack can forcibly (and intelligently)
+try to guess passwords, but don't (can't) guarantee quick success.
+
+If you're worried about users selecting bad passwords, you should
+proactively check when they try to change their password (by modifying
+passwd(1), for example).
+
+=head2 How do I start a process in the background?
+
+(contributed by brian d foy)
+
+There's not a single way to run code in the background so you don't
+have to wait for it to finish before your program moves on to other
+tasks. Process management depends on your particular operating system,
+and many of the techniques are in L<perlipc>.
+
+Several CPAN modules may be able to help, including C<IPC::Open2> or
+C<IPC::Open3>, C<IPC::Run>, C<Parallel::Jobs>,
+C<Parallel::ForkManager>, C<POE>, C<Proc::Background>, and
+C<Win32::Process>. There are many other modules you might use, so
+check those namespaces for other options too.
+
+If you are on a Unix-like system, you might be able to get away with a
+system call where you put an C<&> on the end of the command:
+
+ system("cmd &")
+
+You can also try using C<fork>, as described in L<perlfunc> (although
+this is the same thing that many of the modules will do for you).
+
+=over 4
+
+=item STDIN, STDOUT, and STDERR are shared
+
+Both the main process and the backgrounded one (the "child" process)
+share the same STDIN, STDOUT and STDERR filehandles. If both try to
+access them at once, strange things can happen. You may want to close
+or reopen these for the child. You can get around this with
+C<open>ing a pipe (see L<perlfunc/"open">) but on some systems this
+means that the child process cannot outlive the parent.
+
+=item Signals
+
+You'll have to catch the SIGCHLD signal, and possibly SIGPIPE too.
+SIGCHLD is sent when the backgrounded process finishes. SIGPIPE is
+sent when you write to a filehandle whose child process has closed (an
+untrapped SIGPIPE can cause your program to silently die). This is
+not an issue with C<system("cmd&")>.
+
+=item Zombies
+
+You have to be prepared to "reap" the child process when it finishes.
+
+ $SIG{CHLD} = sub { wait };
+
+ $SIG{CHLD} = 'IGNORE';
+
+You can also use a double fork. You immediately C<wait()> for your
+first child, and the init daemon will C<wait()> for your grandchild once
+it exits.
+
+ unless ($pid = fork) {
+ unless (fork) {
+ exec "what you really wanna do";
+ die "exec failed!";
+ }
+ exit 0;
+ }
+ waitpid($pid, 0);
+
+See L<perlipc/"Signals"> for other examples of code to do this.
+Zombies are not an issue with C<system("prog &")>.
+
+=back
+
+=head2 How do I trap control characters/signals?
+
+You don't actually "trap" a control character. Instead, that character
+generates a signal which is sent to your terminal's currently
+foregrounded process group, which you then trap in your process.
+Signals are documented in L<perlipc/"Signals"> and the
+section on "Signals" in the Camel.
+
+You can set the values of the C<%SIG> hash to be the functions you want
+to handle the signal. After perl catches the signal, it looks in C<%SIG>
+for a key with the same name as the signal, then calls the subroutine
+value for that key.
+
+ # as an anonymous subroutine
+
+ $SIG{INT} = sub { syswrite(STDERR, "ouch\n", 5 ) };
+
+ # or a reference to a function
+
+ $SIG{INT} = \&ouch;
+
+ # or the name of the function as a string
+
+ $SIG{INT} = "ouch";
+
+Perl versions before 5.8 had in its C source code signal handlers which
+would catch the signal and possibly run a Perl function that you had set
+in C<%SIG>. This violated the rules of signal handling at that level
+causing perl to dump core. Since version 5.8.0, perl looks at C<%SIG>
+B<after> the signal has been caught, rather than while it is being caught.
+Previous versions of this answer were incorrect.
+
+=head2 How do I modify the shadow password file on a Unix system?
+
+If perl was installed correctly and your shadow library was written
+properly, the C<getpw*()> functions described in L<perlfunc> should in
+theory provide (read-only) access to entries in the shadow password
+file. To change the file, make a new shadow password file (the format
+varies from system to system--see L<passwd> for specifics) and use
+C<pwd_mkdb(8)> to install it (see L<pwd_mkdb> for more details).
+
+=head2 How do I set the time and date?
+
+Assuming you're running under sufficient permissions, you should be
+able to set the system-wide date and time by running the C<date(1)>
+program. (There is no way to set the time and date on a per-process
+basis.) This mechanism will work for Unix, MS-DOS, Windows, and NT;
+the VMS equivalent is C<set time>.
+
+However, if all you want to do is change your time zone, you can
+probably get away with setting an environment variable:
+
+ $ENV{TZ} = "MST7MDT"; # Unixish
+ $ENV{'SYS$TIMEZONE_DIFFERENTIAL'}="-5" # vms
+ system "trn comp.lang.perl.misc";
+
+=head2 How can I sleep() or alarm() for under a second?
+X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
+
+If you want finer granularity than the 1 second that the C<sleep()>
+function provides, the easiest way is to use the C<select()> function as
+documented in L<perlfunc/"select">. Try the C<Time::HiRes> and
+the C<BSD::Itimer> modules (available from CPAN, and starting from
+Perl 5.8 C<Time::HiRes> is part of the standard distribution).
+
+=head2 How can I measure time under a second?
+X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
+
+(contributed by brian d foy)
+
+The C<Time::HiRes> module (part of the standard distribution as of
+Perl 5.8) measures time with the C<gettimeofday()> system call, which
+returns the time in microseconds since the epoch. If you can't install
+C<Time::HiRes> for older Perls and you are on a Unixish system, you
+may be able to call C<gettimeofday(2)> directly. See
+L<perlfunc/syscall>.
+
+=head2 How can I do an atexit() or setjmp()/longjmp()? (Exception handling)
+
+You can use the C<END> block to simulate C<atexit()>. Each package's
+C<END> block is called when the program or thread ends See L<perlmod>
+manpage for more details about C<END> blocks.
+
+For example, you can use this to make sure your filter program managed
+to finish its output without filling up the disk:
+
+ END {
+ close(STDOUT) || die "stdout close failed: $!";
+ }
+
+The C<END> block isn't called when untrapped signals kill the program,
+though, so if you use C<END> blocks you should also use
+
+ use sigtrap qw(die normal-signals);
+
+Perl's exception-handling mechanism is its C<eval()> operator. You
+can use C<eval()> as C<setjmp> and C<die()> as C<longjmp>. For
+details of this, see the section on signals, especially the time-out
+handler for a blocking C<flock()> in L<perlipc/"Signals"> or the
+section on "Signals" in I<Programming Perl>.
+
+If exception handling is all you're interested in, use one of the
+many CPAN modules that handle exceptions, such as C<Try::Tiny>.
+
+If you want the C<atexit()> syntax (and an C<rmexit()> as well), try the
+C<AtExit> module available from CPAN.
+
+=head2 Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean?
+
+Some Sys-V based systems, notably Solaris 2.X, redefined some of the
+standard socket constants. Since these were constant across all
+architectures, they were often hardwired into perl code. The proper
+way to deal with this is to "use Socket" to get the correct values.
+
+Note that even though SunOS and Solaris are binary compatible, these
+values are different. Go figure.
+
+=head2 How can I call my system's unique C functions from Perl?
+
+In most cases, you write an external module to do it--see the answer
+to "Where can I learn about linking C with Perl? [h2xs, xsubpp]".
+However, if the function is a system call, and your system supports
+C<syscall()>, you can use the C<syscall> function (documented in
+L<perlfunc>).
+
+Remember to check the modules that came with your distribution, and
+CPAN as well--someone may already have written a module to do it. On
+Windows, try C<Win32::API>. On Macs, try C<Mac::Carbon>. If no module
+has an interface to the C function, you can inline a bit of C in your
+Perl source with C<Inline::C>.
+
+=head2 Where do I get the include files to do ioctl() or syscall()?
+
+Historically, these would be generated by the C<h2ph> tool, part of the
+standard perl distribution. This program converts C<cpp(1)> directives
+in C header files to files containing subroutine definitions, like
+C<&SYS_getitimer>, which you can use as arguments to your functions.
+It doesn't work perfectly, but it usually gets most of the job done.
+Simple files like F<errno.h>, F<syscall.h>, and F<socket.h> were fine,
+but the hard ones like F<ioctl.h> nearly always need to be hand-edited.
+Here's how to install the *.ph files:
+
+ 1. become super-user
+ 2. cd /usr/include
+ 3. h2ph *.h */*.h
+
+If your system supports dynamic loading, for reasons of portability and
+sanity you probably ought to use C<h2xs> (also part of the standard perl
+distribution). This tool converts C header files to Perl extensions.
+See L<perlxstut> for how to get started with C<h2xs>.
+
+If your system doesn't support dynamic loading, you still probably
+ought to use C<h2xs>. See L<perlxstut> and L<ExtUtils::MakeMaker> for
+more information (in brief, just use B<make perl> instead of a plain
+B<make> to rebuild perl with a new static extension).
+
+=head2 Why do setuid perl scripts complain about kernel problems?
+
+Some operating systems have bugs in the kernel that make setuid
+scripts inherently insecure. Perl gives you a number of options
+(described in L<perlsec>) to work around such systems.
+
+=head2 How can I open a pipe both to and from a command?
+
+The C<IPC::Open2> module (part of the standard perl distribution) is
+an easy-to-use approach that internally uses C<pipe()>, C<fork()>, and
+C<exec()> to do the job. Make sure you read the deadlock warnings in
+its documentation, though (see L<IPC::Open2>). See
+L<perlipc/"Bidirectional Communication with Another Process"> and
+L<perlipc/"Bidirectional Communication with Yourself">
+
+You may also use the C<IPC::Open3> module (part of the standard perl
+distribution), but be warned that it has a different order of
+arguments from C<IPC::Open2> (see L<IPC::Open3>).
+
+=head2 Why can't I get the output of a command with system()?
+
+You're confusing the purpose of C<system()> and backticks (``). C<system()>
+runs a command and returns exit status information (as a 16 bit value:
+the low 7 bits are the signal the process died from, if any, and
+the high 8 bits are the actual exit value). Backticks (``) run a
+command and return what it sent to STDOUT.
+
+ $exit_status = system("mail-users");
+ $output_string = `ls`;
+
+=head2 How can I capture STDERR from an external command?
+
+There are three basic ways of running external commands:
+
+ system $cmd; # using system()
+ $output = `$cmd`; # using backticks (``)
+ open (PIPE, "cmd |"); # using open()
+
+With C<system()>, both STDOUT and STDERR will go the same place as the
+script's STDOUT and STDERR, unless the C<system()> command redirects them.
+Backticks and C<open()> read B<only> the STDOUT of your command.
+
+You can also use the C<open3()> function from C<IPC::Open3>. Benjamin
+Goldberg provides some sample code:
+
+To capture a program's STDOUT, but discard its STDERR:
+
+ use IPC::Open3;
+ use File::Spec;
+ use Symbol qw(gensym);
+ open(NULL, ">", File::Spec->devnull);
+ my $pid = open3(gensym, \*PH, ">&NULL", "cmd");
+ while( <PH> ) { }
+ waitpid($pid, 0);
+
+To capture a program's STDERR, but discard its STDOUT:
+
+ use IPC::Open3;
+ use File::Spec;
+ use Symbol qw(gensym);
+ open(NULL, ">", File::Spec->devnull);
+ my $pid = open3(gensym, ">&NULL", \*PH, "cmd");
+ while( <PH> ) { }
+ waitpid($pid, 0);
+
+To capture a program's STDERR, and let its STDOUT go to our own STDERR:
+
+ use IPC::Open3;
+ use Symbol qw(gensym);
+ my $pid = open3(gensym, ">&STDERR", \*PH, "cmd");
+ while( <PH> ) { }
+ waitpid($pid, 0);
+
+To read both a command's STDOUT and its STDERR separately, you can
+redirect them to temp files, let the command run, then read the temp
+files:
+
+ use IPC::Open3;
+ use Symbol qw(gensym);
+ use IO::File;
+ local *CATCHOUT = IO::File->new_tmpfile;
+ local *CATCHERR = IO::File->new_tmpfile;
+ my $pid = open3(gensym, ">&CATCHOUT", ">&CATCHERR", "cmd");
+ waitpid($pid, 0);
+ seek $_, 0, 0 for \*CATCHOUT, \*CATCHERR;
+ while( <CATCHOUT> ) {}
+ while( <CATCHERR> ) {}
+
+But there's no real need for B<both> to be tempfiles... the following
+should work just as well, without deadlocking:
+
+ use IPC::Open3;
+ use Symbol qw(gensym);
+ use IO::File;
+ local *CATCHERR = IO::File->new_tmpfile;
+ my $pid = open3(gensym, \*CATCHOUT, ">&CATCHERR", "cmd");
+ while( <CATCHOUT> ) {}
+ waitpid($pid, 0);
+ seek CATCHERR, 0, 0;
+ while( <CATCHERR> ) {}
+
+And it'll be faster, too, since we can begin processing the program's
+stdout immediately, rather than waiting for the program to finish.
+
+With any of these, you can change file descriptors before the call:
+
+ open(STDOUT, ">logfile");
+ system("ls");
+
+or you can use Bourne shell file-descriptor redirection:
+
+ $output = `$cmd 2>some_file`;
+ open (PIPE, "cmd 2>some_file |");
+
+You can also use file-descriptor redirection to make STDERR a
+duplicate of STDOUT:
+
+ $output = `$cmd 2>&1`;
+ open (PIPE, "cmd 2>&1 |");
+
+Note that you I<cannot> simply open STDERR to be a dup of STDOUT
+in your Perl program and avoid calling the shell to do the redirection.
+This doesn't work:
+
+ open(STDERR, ">&STDOUT");
+ $alloutput = `cmd args`; # stderr still escapes
+
+This fails because the C<open()> makes STDERR go to where STDOUT was
+going at the time of the C<open()>. The backticks then make STDOUT go to
+a string, but don't change STDERR (which still goes to the old
+STDOUT).
+
+Note that you I<must> use Bourne shell (C<sh(1)>) redirection syntax in
+backticks, not C<csh(1)>! Details on why Perl's C<system()> and backtick
+and pipe opens all use the Bourne shell are in the
+F<versus/csh.whynot> article in the "Far More Than You Ever Wanted To
+Know" collection in http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz . To
+capture a command's STDERR and STDOUT together:
+
+ $output = `cmd 2>&1`; # either with backticks
+ $pid = open(PH, "cmd 2>&1 |"); # or with an open pipe
+ while (<PH>) { } # plus a read
+
+To capture a command's STDOUT but discard its STDERR:
+
+ $output = `cmd 2>/dev/null`; # either with backticks
+ $pid = open(PH, "cmd 2>/dev/null |"); # or with an open pipe
+ while (<PH>) { } # plus a read
+
+To capture a command's STDERR but discard its STDOUT:
+
+ $output = `cmd 2>&1 1>/dev/null`; # either with backticks
+ $pid = open(PH, "cmd 2>&1 1>/dev/null |"); # or with an open pipe
+ while (<PH>) { } # plus a read
+
+To exchange a command's STDOUT and STDERR in order to capture the STDERR
+but leave its STDOUT to come out our old STDERR:
+
+ $output = `cmd 3>&1 1>&2 2>&3 3>&-`; # either with backticks
+ $pid = open(PH, "cmd 3>&1 1>&2 2>&3 3>&-|");# or with an open pipe
+ while (<PH>) { } # plus a read
+
+To read both a command's STDOUT and its STDERR separately, it's easiest
+to redirect them separately to files, and then read from those files
+when the program is done:
+
+ system("program args 1>program.stdout 2>program.stderr");
+
+Ordering is important in all these examples. That's because the shell
+processes file descriptor redirections in strictly left to right order.
+
+ system("prog args 1>tmpfile 2>&1");
+ system("prog args 2>&1 1>tmpfile");
+
+The first command sends both standard out and standard error to the
+temporary file. The second command sends only the old standard output
+there, and the old standard error shows up on the old standard out.
+
+=head2 Why doesn't open() return an error when a pipe open fails?
+
+If the second argument to a piped C<open()> contains shell
+metacharacters, perl C<fork()>s, then C<exec()>s a shell to decode the
+metacharacters and eventually run the desired program. If the program
+couldn't be run, it's the shell that gets the message, not Perl. All
+your Perl program can find out is whether the shell itself could be
+successfully started. You can still capture the shell's STDERR and
+check it for error messages. See L<"How can I capture STDERR from an
+external command?"> elsewhere in this document, or use the
+C<IPC::Open3> module.
+
+If there are no shell metacharacters in the argument of C<open()>, Perl
+runs the command directly, without using the shell, and can correctly
+report whether the command started.
+
+=head2 What's wrong with using backticks in a void context?
+
+Strictly speaking, nothing. Stylistically speaking, it's not a good
+way to write maintainable code. Perl has several operators for
+running external commands. Backticks are one; they collect the output
+from the command for use in your program. The C<system> function is
+another; it doesn't do this.
+
+Writing backticks in your program sends a clear message to the readers
+of your code that you wanted to collect the output of the command.
+Why send a clear message that isn't true?
+
+Consider this line:
+
+ `cat /etc/termcap`;
+
+You forgot to check C<$?> to see whether the program even ran
+correctly. Even if you wrote
+
+ print `cat /etc/termcap`;
+
+this code could and probably should be written as
+
+ system("cat /etc/termcap") == 0
+ or die "cat program failed!";
+
+which will echo the cat command's output as it is generated, instead
+of waiting until the program has completed to print it out. It also
+checks the return value.
+
+C<system> also provides direct control over whether shell wildcard
+processing may take place, whereas backticks do not.
+
+=head2 How can I call backticks without shell processing?
+
+This is a bit tricky. You can't simply write the command
+like this:
+
+ @ok = `grep @opts '$search_string' @filenames`;
+
+As of Perl 5.8.0, you can use C<open()> with multiple arguments.
+Just like the list forms of C<system()> and C<exec()>, no shell
+escapes happen.
+
+ open( GREP, "-|", 'grep', @opts, $search_string, @filenames );
+ chomp(@ok = <GREP>);
+ close GREP;
+
+You can also:
+
+ my @ok = ();
+ if (open(GREP, "-|")) {
+ while (<GREP>) {
+ chomp;
+ push(@ok, $_);
+ }
+ close GREP;
+ } else {
+ exec 'grep', @opts, $search_string, @filenames;
+ }
+
+Just as with C<system()>, no shell escapes happen when you C<exec()> a
+list. Further examples of this can be found in L<perlipc/"Safe Pipe
+Opens">.
+
+Note that if you're using Windows, no solution to this vexing issue is
+even possible. Even if Perl were to emulate C<fork()>, you'd still be
+stuck, because Windows does not have an argc/argv-style API.
+
+=head2 Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?
+
+This happens only if your perl is compiled to use stdio instead of
+perlio, which is the default. Some (maybe all?) stdios set error and
+eof flags that you may need to clear. The C<POSIX> module defines
+C<clearerr()> that you can use. That is the technically correct way to
+do it. Here are some less reliable workarounds:
+
+=over 4
+
+=item 1
+
+Try keeping around the seekpointer and go there, like this:
+
+ $where = tell(LOG);
+ seek(LOG, $where, 0);
+
+=item 2
+
+If that doesn't work, try seeking to a different part of the file and
+then back.
+
+=item 3
+
+If that doesn't work, try seeking to a different part of
+the file, reading something, and then seeking back.
+
+=item 4
+
+If that doesn't work, give up on your stdio package and use sysread.
+
+=back
+
+=head2 How can I convert my shell script to perl?
+
+Learn Perl and rewrite it. Seriously, there's no simple converter.
+Things that are awkward to do in the shell are easy to do in Perl, and
+this very awkwardness is what would make a shell->perl converter
+nigh-on impossible to write. By rewriting it, you'll think about what
+you're really trying to do, and hopefully will escape the shell's
+pipeline datastream paradigm, which while convenient for some matters,
+causes many inefficiencies.
+
+=head2 Can I use perl to run a telnet or ftp session?
+
+Try the C<Net::FTP>, C<TCP::Client>, and C<Net::Telnet> modules
+(available from CPAN).
+http://www.cpan.org/scripts/netstuff/telnet.emul.shar will also help
+for emulating the telnet protocol, but C<Net::Telnet> is quite
+probably easier to use.
+
+If all you want to do is pretend to be telnet but don't need
+the initial telnet handshaking, then the standard dual-process
+approach will suffice:
+
+ use IO::Socket; # new in 5.004
+ $handle = IO::Socket::INET->new('www.perl.com:80')
+ or die "can't connect to port 80 on www.perl.com: $!";
+ $handle->autoflush(1);
+ if (fork()) { # XXX: undef means failure
+ select($handle);
+ print while <STDIN>; # everything from stdin to socket
+ } else {
+ print while <$handle>; # everything from socket to stdout
+ }
+ close $handle;
+ exit;
+
+=head2 How can I write expect in Perl?
+
+Once upon a time, there was a library called L<chat2.pl> (part of the
+standard perl distribution), which never really got finished. If you
+find it somewhere, I<don't use it>. These days, your best bet is to
+look at the Expect module available from CPAN, which also requires two
+other modules from CPAN, C<IO::Pty> and C<IO::Stty>.
+
+=head2 Is there a way to hide perl's command line from programs such as "ps"?
+
+First of all note that if you're doing this for security reasons (to
+avoid people seeing passwords, for example) then you should rewrite
+your program so that critical information is never given as an
+argument. Hiding the arguments won't make your program completely
+secure.
+
+To actually alter the visible command line, you can assign to the
+variable $0 as documented in L<perlvar>. This won't work on all
+operating systems, though. Daemon programs like sendmail place their
+state there, as in:
+
+ $0 = "orcus [accepting connections]";
+
+=head2 I {changed directory, modified my environment} in a perl script. How come the change disappeared when I exited the script? How do I get my changes to be visible?
+
+=over 4
+
+=item Unix
+
+In the strictest sense, it can't be done--the script executes as a
+different process from the shell it was started from. Changes to a
+process are not reflected in its parent--only in any children
+created after the change. There is shell magic that may allow you to
+fake it by C<eval()>ing the script's output in your shell; check out the
+comp.unix.questions FAQ for details.
+
+=back
+
+=head2 How do I close a process's filehandle without waiting for it to complete?
+
+Assuming your system supports such things, just send an appropriate signal
+to the process (see L<perlfunc/"kill">). It's common to first send a TERM
+signal, wait a little bit, and then send a KILL signal to finish it off.
+
+=head2 How do I fork a daemon process?
+
+If by daemon process you mean one that's detached (disassociated from
+its tty), then the following process is reported to work on most
+Unixish systems. Non-Unix users should check their Your_OS::Process
+module for other solutions.
+
+=over 4
+
+=item *
+
+Open /dev/tty and use the TIOCNOTTY ioctl on it. See L<tty>
+for details. Or better yet, you can just use the C<POSIX::setsid()>
+function, so you don't have to worry about process groups.
+
+=item *
+
+Change directory to /
+
+=item *
+
+Reopen STDIN, STDOUT, and STDERR so they're not connected to the old
+tty.
+
+=item *
+
+Background yourself like this:
+
+ fork && exit;
+
+=back
+
+The C<Proc::Daemon> module, available from CPAN, provides a function to
+perform these actions for you.
+
+=head2 How do I find out if I'm running interactively or not?
+
+(contributed by brian d foy)
+
+This is a difficult question to answer, and the best answer is
+only a guess.
+
+What do you really want to know? If you merely want to know if one of
+your filehandles is connected to a terminal, you can try the C<-t>
+file test:
+
+ if( -t STDOUT ) {
+ print "I'm connected to a terminal!\n";
+ }
+
+However, you might be out of luck if you expect that means there is a
+real person on the other side. With the C<Expect> module, another
+program can pretend to be a person. The program might even come close
+to passing the Turing test.
+
+The C<IO::Interactive> module does the best it can to give you an
+answer. Its C<is_interactive> function returns an output filehandle;
+that filehandle points to standard output if the module thinks the
+session is interactive. Otherwise, the filehandle is a null handle
+that simply discards the output:
+
+ use IO::Interactive;
+
+ print { is_interactive } "I might go to standard output!\n";
+
+This still doesn't guarantee that a real person is answering your
+prompts or reading your output.
+
+If you want to know how to handle automated testing for your
+distribution, you can check the environment. The CPAN
+Testers, for instance, set the value of C<AUTOMATED_TESTING>:
+
+ unless( $ENV{AUTOMATED_TESTING} ) {
+ print "Hello interactive tester!\n";
+ }
+
+=head2 How do I timeout a slow event?
+
+Use the C<alarm()> function, probably in conjunction with a signal
+handler, as documented in L<perlipc/"Signals"> and the section on
+"Signals" in the Camel. You may instead use the more flexible
+C<Sys::AlarmCall> module available from CPAN.
+
+The C<alarm()> function is not implemented on all versions of Windows.
+Check the documentation for your specific version of Perl.
+
+=head2 How do I set CPU limits?
+X<BSD::Resource> X<limit> X<CPU>
+
+(contributed by Xho)
+
+Use the C<BSD::Resource> module from CPAN. As an example:
+
+ use BSD::Resource;
+ setrlimit(RLIMIT_CPU,10,20) or die $!;
+
+This sets the soft and hard limits to 10 and 20 seconds, respectively.
+After 10 seconds of time spent running on the CPU (not "wall" time),
+the process will be sent a signal (XCPU on some systems) which, if not
+trapped, will cause the process to terminate. If that signal is
+trapped, then after 10 more seconds (20 seconds in total) the process
+will be killed with a non-trappable signal.
+
+See the C<BSD::Resource> and your systems documentation for the gory
+details.
+
+=head2 How do I avoid zombies on a Unix system?
+
+Use the reaper code from L<perlipc/"Signals"> to call C<wait()> when a
+SIGCHLD is received, or else use the double-fork technique described
+in L<perlfaq8/"How do I start a process in the background?">.
+
+=head2 How do I use an SQL database?
+
+The C<DBI> module provides an abstract interface to most database
+servers and types, including Oracle, DB2, Sybase, mysql, Postgresql,
+ODBC, and flat files. The DBI module accesses each database type
+through a database driver, or DBD. You can see a complete list of
+available drivers on CPAN: http://www.cpan.org/modules/by-module/DBD/ .
+You can read more about DBI on http://dbi.perl.org .
+
+Other modules provide more specific access: C<Win32::ODBC>, C<Alzabo>,
+C<iodbc>, and others found on CPAN Search: http://search.cpan.org .
+
+=head2 How do I make a system() exit on control-C?
+
+You can't. You need to imitate the C<system()> call (see L<perlipc> for
+sample code) and then have a signal handler for the INT signal that
+passes the signal on to the subprocess. Or you can check for it:
+
+ $rc = system($cmd);
+ if ($rc & 127) { die "signal death" }
+
+=head2 How do I open a file without blocking?
+
+If you're lucky enough to be using a system that supports
+non-blocking reads (most Unixish systems do), you need only to use the
+C<O_NDELAY> or C<O_NONBLOCK> flag from the C<Fcntl> module in conjunction with
+C<sysopen()>:
+
+ use Fcntl;
+ sysopen(FH, "/foo/somefile", O_WRONLY|O_NDELAY|O_CREAT, 0644)
+ or die "can't open /foo/somefile: $!":
+
+=head2 How do I tell the difference between errors from the shell and perl?
+
+(answer contributed by brian d foy)
+
+When you run a Perl script, something else is running the script for you,
+and that something else may output error messages. The script might
+emit its own warnings and error messages. Most of the time you cannot
+tell who said what.
+
+You probably cannot fix the thing that runs perl, but you can change how
+perl outputs its warnings by defining a custom warning and die functions.
+
+Consider this script, which has an error you may not notice immediately.
+
+ #!/usr/locl/bin/perl
+
+ print "Hello World\n";
+
+I get an error when I run this from my shell (which happens to be
+bash). That may look like perl forgot it has a C<print()> function,
+but my shebang line is not the path to perl, so the shell runs the
+script, and I get the error.
+
+ $ ./test
+ ./test: line 3: print: command not found
+
+A quick and dirty fix involves a little bit of code, but this may be all
+you need to figure out the problem.
+
+ #!/usr/bin/perl -w
+
+ BEGIN {
+ $SIG{__WARN__} = sub{ print STDERR "Perl: ", @_; };
+ $SIG{__DIE__} = sub{ print STDERR "Perl: ", @_; exit 1};
+ }
+
+ $a = 1 + undef;
+ $x / 0;
+ __END__
+
+The perl message comes out with "Perl" in front. The C<BEGIN> block
+works at compile time so all of the compilation errors and warnings
+get the "Perl:" prefix too.
+
+ Perl: Useless use of division (/) in void context at ./test line 9.
+ Perl: Name "main::a" used only once: possible typo at ./test line 8.
+ Perl: Name "main::x" used only once: possible typo at ./test line 9.
+ Perl: Use of uninitialized value in addition (+) at ./test line 8.
+ Perl: Use of uninitialized value in division (/) at ./test line 9.
+ Perl: Illegal division by zero at ./test line 9.
+ Perl: Illegal division by zero at -e line 3.
+
+If I don't see that "Perl:", it's not from perl.
+
+You could also just know all the perl errors, and although there are
+some people who may know all of them, you probably don't. However, they
+all should be in the L<perldiag> manpage. If you don't find the error in
+there, it probably isn't a perl error.
+
+Looking up every message is not the easiest way, so let perl to do it
+for you. Use the diagnostics pragma with turns perl's normal messages
+into longer discussions on the topic.
+
+ use diagnostics;
+
+If you don't get a paragraph or two of expanded discussion, it
+might not be perl's message.
+
+=head2 How do I install a module from CPAN?
+
+(contributed by brian d foy)
+
+The easiest way is to have a module also named CPAN do it for you by using
+the C<cpan> command the comes with Perl. You can give it a list of modules
+to install:
+
+ $ cpan IO::Interactive Getopt::Whatever
+
+If you prefer C<CPANPLUS>, it's just as easy:
+
+ $ cpanp i IO::Interactive Getopt::Whatever
+
+If you want to install a distribution from the current directory, you can
+tell C<CPAN.pm> to install C<.> (the full stop):
+
+ $ cpan .
+
+See the documentation for either of those commands to see what else
+you can do.
+
+If you want to try to install a distribution by yourself, resolving
+all dependencies on your own, you follow one of two possible build
+paths.
+
+For distributions that use I<Makefile.PL>:
+
+ $ perl Makefile.PL
+ $ make test install
+
+For distributions that use I<Build.PL>:
+
+ $ perl Build.PL
+ $ ./Build test
+ $ ./Build install
+
+Some distributions may need to link to libraries or other third-party
+code and their build and installation sequences may be more complicated.
+Check any I<README> or I<INSTALL> files that you may find.
+
+=head2 What's the difference between require and use?
+
+(contributed by brian d foy)
+
+Perl runs C<require> statement at run-time. Once Perl loads, compiles,
+and runs the file, it doesn't do anything else. The C<use> statement
+is the same as a C<require> run at compile-time, but Perl also calls the
+C<import> method for the loaded package. These two are the same:
+
+ use MODULE qw(import list);
+
+ BEGIN {
+ require MODULE;
+ MODULE->import(import list);
+ }
+
+However, you can suppress the C<import> by using an explicit, empty
+import list. Both of these still happen at compile-time:
+
+ use MODULE ();
+
+ BEGIN {
+ require MODULE;
+ }
+
+Since C<use> will also call the C<import> method, the actual value
+for C<MODULE> must be a bareword. That is, C<use> cannot load files
+by name, although C<require> can:
+
+ require "$ENV{HOME}/lib/Foo.pm"; # no @INC searching!
+
+See the entry for C<use> in L<perlfunc> for more details.
+
+=head2 How do I keep my own module/library directory?
+
+When you build modules, tell Perl where to install the modules.
+
+If you want to install modules for your own use, the easiest way might
+be C<local::lib>, which you can download from CPAN. It sets various
+installation settings for you, and uses those same settings within
+your programs.
+
+If you want more flexibility, you need to configure your CPAN client
+for your particular situation.
+
+For C<Makefile.PL>-based distributions, use the INSTALL_BASE option
+when generating Makefiles:
+
+ perl Makefile.PL INSTALL_BASE=/mydir/perl
+
+You can set this in your C<CPAN.pm> configuration so modules
+automatically install in your private library directory when you use
+the CPAN.pm shell:
+
+ % cpan
+ cpan> o conf makepl_arg INSTALL_BASE=/mydir/perl
+ cpan> o conf commit
+
+For C<Build.PL>-based distributions, use the --install_base option:
+
+ perl Build.PL --install_base /mydir/perl
+
+You can configure C<CPAN.pm> to automatically use this option too:
+
+ % cpan
+ cpan> o conf mbuild_arg "--install_base /mydir/perl"
+ cpan> o conf commit
+
+INSTALL_BASE tells these tools to put your modules into
+F</mydir/perl/lib/perl5>. See L<How do I add a directory to my
+include path (@INC) at runtime?> for details on how to run your newly
+installed modules.
+
+There is one caveat with INSTALL_BASE, though, since it acts
+differently than the PREFIX and LIB settings that older versions of
+C<ExtUtils::MakeMaker> advocated. INSTALL_BASE does not support
+installing modules for multiple versions of Perl or different
+architectures under the same directory. You should consider if you
+really want that , and if you do, use the older PREFIX and LIB
+settings. See the C<ExtUtils::Makemaker> documentation for more details.
+
+=head2 How do I add the directory my program lives in to the module/library search path?
+
+(contributed by brian d foy)
+
+If you know the directory already, you can add it to C<@INC> as you would
+for any other directory. You might <use lib> if you know the directory
+at compile time:
+
+ use lib $directory;
+
+The trick in this task is to find the directory. Before your script does
+anything else (such as a C<chdir>), you can get the current working
+directory with the C<Cwd> module, which comes with Perl:
+
+ BEGIN {
+ use Cwd;
+ our $directory = cwd;
+ }
+
+ use lib $directory;
+
+You can do a similar thing with the value of C<$0>, which holds the
+script name. That might hold a relative path, but C<rel2abs> can turn
+it into an absolute path. Once you have the
+
+ BEGIN {
+ use File::Spec::Functions qw(rel2abs);
+ use File::Basename qw(dirname);
+
+ my $path = rel2abs( $0 );
+ our $directory = dirname( $path );
+ }
+
+ use lib $directory;
+
+The C<FindBin> module, which comes with Perl, might work. It finds the
+directory of the currently running script and puts it in C<$Bin>, which
+you can then use to construct the right library path:
+
+ use FindBin qw($Bin);
+
+You can also use C<local::lib> to do much of the same thing. Install
+modules using C<local::lib>'s settings then use the module in your
+program:
+
+ use local::lib; # sets up a local lib at ~/perl5
+
+See the C<local::lib> documentation for more details.
+
+=head2 How do I add a directory to my include path (@INC) at runtime?
+
+Here are the suggested ways of modifying your include path, including
+environment variables, run-time switches, and in-code statements:
+
+=over 4
+
+=item the C<PERLLIB> environment variable
+
+ $ export PERLLIB=/path/to/my/dir
+ $ perl program.pl
+
+=item the C<PERL5LIB> environment variable
+
+ $ export PERL5LIB=/path/to/my/dir
+ $ perl program.pl
+
+=item the C<perl -Idir> command line flag
+
+ $ perl -I/path/to/my/dir program.pl
+
+=item the C<lib> pragma:
+
+ use lib "$ENV{HOME}/myown_perllib";
+
+=item the C<local::lib> module:
+
+ use local::lib;
+
+ use local::lib "~/myown_perllib";
+
+=back
+
+The last is particularly useful because it knows about machine
+dependent architectures. The C<lib.pm> pragmatic module was first
+included with the 5.002 release of Perl.
+
+=head2 What is socket.ph and where do I get it?
+
+It's a Perl 4 style file defining values for system networking
+constants. Sometimes it is built using C<h2ph> when Perl is installed,
+but other times it is not. Modern programs C<use Socket;> instead.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod
new file mode 100644
index 00000000000..fa9ef116737
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq9.pod
@@ -0,0 +1,682 @@
+=head1 NAME
+
+perlfaq9 - Networking
+
+=head1 DESCRIPTION
+
+This section deals with questions related to networking, the internet,
+and a few on the web.
+
+=head2 What is the correct form of response from a CGI script?
+
+(Alan Flavell <flavell+www@a5.ph.gla.ac.uk> answers...)
+
+The Common Gateway Interface (CGI) specifies a software interface between
+a program ("CGI script") and a web server (HTTPD). It is not specific
+to Perl, and has its own FAQs and tutorials, and usenet group,
+comp.infosystems.www.authoring.cgi
+
+The CGI specification is outlined in an informational RFC:
+http://www.ietf.org/rfc/rfc3875
+
+Other relevant documentation listed in: http://www.perl.org/CGI_MetaFAQ.html
+
+These Perl FAQs very selectively cover some CGI issues. However, Perl
+programmers are strongly advised to use the C<CGI.pm> module, to take care
+of the details for them.
+
+The similarity between CGI response headers (defined in the CGI
+specification) and HTTP response headers (defined in the HTTP
+specification, RFC2616) is intentional, but can sometimes be confusing.
+
+The CGI specification defines two kinds of script: the "Parsed Header"
+script, and the "Non Parsed Header" (NPH) script. Check your server
+documentation to see what it supports. "Parsed Header" scripts are
+simpler in various respects. The CGI specification allows any of the
+usual newline representations in the CGI response (it's the server's
+job to create an accurate HTTP response based on it). So "\n" written in
+text mode is technically correct, and recommended. NPH scripts are more
+tricky: they must put out a complete and accurate set of HTTP
+transaction response headers; the HTTP specification calls for records
+to be terminated with carriage-return and line-feed, i.e ASCII \015\012
+written in binary mode.
+
+Using C<CGI.pm> gives excellent platform independence, including EBCDIC
+systems. C<CGI.pm> selects an appropriate newline representation
+(C<$CGI::CRLF>) and sets binmode as appropriate.
+
+=head2 My CGI script runs from the command line but not the browser. (500 Server Error)
+
+Several things could be wrong. You can go through the "Troubleshooting
+Perl CGI scripts" guide at
+
+ http://www.perl.org/troubleshooting_CGI.html
+
+If, after that, you can demonstrate that you've read the FAQs and that
+your problem isn't something simple that can be easily answered, you'll
+probably receive a courteous and useful reply to your question if you
+post it on comp.infosystems.www.authoring.cgi (if it's something to do
+with HTTP or the CGI protocols). Questions that appear to be Perl
+questions but are really CGI ones that are posted to comp.lang.perl.misc
+are not so well received.
+
+The useful FAQs, related documents, and troubleshooting guides are
+listed in the CGI Meta FAQ:
+
+ http://www.perl.org/CGI_MetaFAQ.html
+
+=head2 How can I get better error messages from a CGI program?
+
+Use the C<CGI::Carp> module. It replaces C<warn> and C<die>, plus the
+normal C<Carp> modules C<carp>, C<croak>, and C<confess> functions with
+more verbose and safer versions. It still sends them to the normal
+server error log.
+
+ use CGI::Carp;
+ warn "This is a complaint";
+ die "But this one is serious";
+
+The following use of C<CGI::Carp> also redirects errors to a file of your choice,
+placed in a C<BEGIN> block to catch compile-time warnings as well:
+
+ BEGIN {
+ use CGI::Carp qw(carpout);
+ open(LOG, ">>/var/local/cgi-logs/mycgi-log")
+ or die "Unable to append to mycgi-log: $!\n";
+ carpout(*LOG);
+ }
+
+You can even arrange for fatal errors to go back to the client browser,
+which is nice for your own debugging, but might confuse the end user.
+
+ use CGI::Carp qw(fatalsToBrowser);
+ die "Bad error here";
+
+Even if the error happens before you get the HTTP header out, the module
+will try to take care of this to avoid the dreaded server 500 errors.
+Normal warnings still go out to the server error log (or wherever
+you've sent them with C<carpout>) with the application name and date
+stamp prepended.
+
+=head2 How do I remove HTML from a string?
+
+The most correct way (albeit not the fastest) is to use C<HTML::Parser>
+from CPAN. Another mostly correct
+way is to use C<HTML::FormatText> which not only removes HTML but also
+attempts to do a little simple formatting of the resulting plain text.
+
+Many folks attempt a simple-minded regular expression approach, like
+C<< s/<.*?>//g >>, but that fails in many cases because the tags
+may continue over line breaks, they may contain quoted angle-brackets,
+or HTML comment may be present. Plus, folks forget to convert
+entities--like C<&lt;> for example.
+
+Here's one "simple-minded" approach, that works for most files:
+
+ #!/usr/bin/perl -p0777
+ s/<(?:[^>'"]*|(['"]).*?\1)*>//gs
+
+If you want a more complete solution, see the 3-stage striphtml
+program in
+http://www.cpan.org/authors/Tom_Christiansen/scripts/striphtml.gz
+.
+
+Here are some tricky cases that you should think about when picking
+a solution:
+
+ <IMG SRC = "foo.gif" ALT = "A > B">
+
+ <IMG SRC = "foo.gif"
+ ALT = "A > B">
+
+ <!-- <A comment> -->
+
+ <script>if (a<b && a>c)</script>
+
+ <# Just data #>
+
+ <![INCLUDE CDATA [ >>>>>>>>>>>> ]]>
+
+If HTML comments include other tags, those solutions would also break
+on text like this:
+
+ <!-- This section commented out.
+ <B>You can't see me!</B>
+ -->
+
+=head2 How do I extract URLs?
+
+You can easily extract all sorts of URLs from HTML with
+C<HTML::SimpleLinkExtor> which handles anchors, images, objects,
+frames, and many other tags that can contain a URL. If you need
+anything more complex, you can create your own subclass of
+C<HTML::LinkExtor> or C<HTML::Parser>. You might even use
+C<HTML::SimpleLinkExtor> as an example for something specifically
+suited to your needs.
+
+You can use C<URI::Find> to extract URLs from an arbitrary text document.
+
+Less complete solutions involving regular expressions can save
+you a lot of processing time if you know that the input is simple. One
+solution from Tom Christiansen runs 100 times faster than most
+module based approaches but only extracts URLs from anchors where the first
+attribute is HREF and there are no other attributes.
+
+ #!/usr/bin/perl -n00
+ # qxurl - tchrist@perl.com
+ print "$2\n" while m{
+ < \s*
+ A \s+ HREF \s* = \s* (["']) (.*?) \1
+ \s* >
+ }gsix;
+
+=head2 How do I download a file from the user's machine? How do I open a file on another machine?
+
+In this case, download means to use the file upload feature of HTML
+forms. You allow the web surfer to specify a file to send to your web
+server. To you it looks like a download, and to the user it looks
+like an upload. No matter what you call it, you do it with what's
+known as B<multipart/form-data> encoding. The C<CGI.pm> module (which
+comes with Perl as part of the Standard Library) supports this in the
+C<start_multipart_form()> method, which isn't the same as the C<startform()>
+method.
+
+See the section in the C<CGI.pm> documentation on file uploads for code
+examples and details.
+
+=head2 How do I make an HTML pop-up menu with Perl?
+
+(contributed by brian d foy)
+
+The C<CGI.pm> module (which comes with Perl) has functions to create
+the HTML form widgets. See the C<CGI.pm> documentation for more
+examples.
+
+ use CGI qw/:standard/;
+ print header,
+ start_html('Favorite Animals'),
+
+ start_form,
+ "What's your favorite animal? ",
+ popup_menu(
+ -name => 'animal',
+ -values => [ qw( Llama Alpaca Camel Ram ) ]
+ ),
+ submit,
+
+ end_form,
+ end_html;
+
+=head2 How do I fetch an HTML file?
+
+(contributed by brian d foy)
+
+Use the libwww-perl distribution. The C<LWP::Simple> module can fetch web
+resources and give their content back to you as a string:
+
+ use LWP::Simple qw(get);
+
+ my $html = get( "http://www.example.com/index.html" );
+
+It can also store the resource directly in a file:
+
+ use LWP::Simple qw(getstore);
+
+ getstore( "http://www.example.com/index.html", "foo.html" );
+
+If you need to do something more complicated, you can use
+C<LWP::UserAgent> module to create your own user-agent (e.g. browser)
+to get the job done. If you want to simulate an interactive web
+browser, you can use the C<WWW::Mechanize> module.
+
+=head2 How do I automate an HTML form submission?
+
+If you are doing something complex, such as moving through many pages
+and forms or a web site, you can use C<WWW::Mechanize>. See its
+documentation for all the details.
+
+If you're submitting values using the GET method, create a URL and encode
+the form using the C<query_form> method:
+
+ use LWP::Simple;
+ use URI::URL;
+
+ my $url = url('http://www.perl.com/cgi-bin/cpan_mod');
+ $url->query_form(module => 'DB_File', readme => 1);
+ $content = get($url);
+
+If you're using the POST method, create your own user agent and encode
+the content appropriately.
+
+ use HTTP::Request::Common qw(POST);
+ use LWP::UserAgent;
+
+ $ua = LWP::UserAgent->new();
+ my $req = POST 'http://www.perl.com/cgi-bin/cpan_mod',
+ [ module => 'DB_File', readme => 1 ];
+ $content = $ua->request($req)->as_string;
+
+=head2 How do I decode or create those %-encodings on the web?
+X<URI> X<CGI.pm> X<CGI> X<URI::Escape> X<RFC 2396>
+
+(contributed by brian d foy)
+
+Those C<%> encodings handle reserved characters in URIs, as described
+in RFC 2396, Section 2. This encoding replaces the reserved character
+with the hexadecimal representation of the character's number from
+the US-ASCII table. For instance, a colon, C<:>, becomes C<%3A>.
+
+In CGI scripts, you don't have to worry about decoding URIs if you are
+using C<CGI.pm>. You shouldn't have to process the URI yourself,
+either on the way in or the way out.
+
+If you have to encode a string yourself, remember that you should
+never try to encode an already-composed URI. You need to escape the
+components separately then put them together. To encode a string, you
+can use the the C<URI::Escape> module. The C<uri_escape> function
+returns the escaped string:
+
+ my $original = "Colon : Hash # Percent %";
+
+ my $escaped = uri_escape( $original );
+
+ print "$escaped\n"; # 'Colon%20%3A%20Hash%20%23%20Percent%20%25'
+
+To decode the string, use the C<uri_unescape> function:
+
+ my $unescaped = uri_unescape( $escaped );
+
+ print $unescaped; # back to original
+
+If you wanted to do it yourself, you simply need to replace the
+reserved characters with their encodings. A global substitution
+is one way to do it:
+
+ # encode
+ $string =~ s/([^^A-Za-z0-9\-_.!~*'()])/ sprintf "%%%0x", ord $1 /eg;
+
+ #decode
+ $string =~ s/%([A-Fa-f\d]{2})/chr hex $1/eg;
+
+=head2 How do I redirect to another page?
+
+Specify the complete URL of the destination (even if it is on the same
+server). This is one of the two different kinds of CGI "Location:"
+responses which are defined in the CGI specification for a Parsed Headers
+script. The other kind (an absolute URLpath) is resolved internally to
+the server without any HTTP redirection. The CGI specifications do not
+allow relative URLs in either case.
+
+Use of C<CGI.pm> is strongly recommended. This example shows redirection
+with a complete URL. This redirection is handled by the web browser.
+
+ use CGI qw/:standard/;
+
+ my $url = 'http://www.cpan.org/';
+ print redirect($url);
+
+This example shows a redirection with an absolute URLpath. This
+redirection is handled by the local web server.
+
+ my $url = '/CPAN/index.html';
+ print redirect($url);
+
+But if coded directly, it could be as follows (the final "\n" is
+shown separately, for clarity), using either a complete URL or
+an absolute URLpath.
+
+ print "Location: $url\n"; # CGI response header
+ print "\n"; # end of headers
+
+=head2 How do I put a password on my web pages?
+
+To enable authentication for your web server, you need to configure
+your web server. The configuration is different for different sorts
+of web servers--apache does it differently from iPlanet which does
+it differently from IIS. Check your web server documentation for
+the details for your particular server.
+
+=head2 How do I edit my .htpasswd and .htgroup files with Perl?
+
+The C<HTTPD::UserAdmin> and C<HTTPD::GroupAdmin> modules provide a
+consistent OO interface to these files, regardless of how they're
+stored. Databases may be text, dbm, Berkeley DB or any database with
+a DBI compatible driver. C<HTTPD::UserAdmin> supports files used by the
+"Basic" and "Digest" authentication schemes. Here's an example:
+
+ use HTTPD::UserAdmin ();
+ HTTPD::UserAdmin
+ ->new(DB => "/foo/.htpasswd")
+ ->add($username => $password);
+
+=head2 How do I make sure users can't enter values into a form that cause my CGI script to do bad things?
+
+See the security references listed in the CGI Meta FAQ
+
+ http://www.perl.org/CGI_MetaFAQ.html
+
+=head2 How do I parse a mail header?
+
+For a quick-and-dirty solution, try this solution derived
+from L<perlfunc/split>:
+
+ $/ = '';
+ $header = <MSG>;
+ $header =~ s/\n\s+/ /g; # merge continuation lines
+ %head = ( UNIX_FROM_LINE, split /^([-\w]+):\s*/m, $header );
+
+That solution doesn't do well if, for example, you're trying to
+maintain all the Received lines. A more complete approach is to use
+the C<Mail::Header> module from CPAN (part of the C<MailTools> package).
+
+=head2 How do I decode a CGI form?
+
+(contributed by brian d foy)
+
+Use the C<CGI.pm> module that comes with Perl. It's quick,
+it's easy, and it actually does quite a bit of work to
+ensure things happen correctly. It handles GET, POST, and
+HEAD requests, multipart forms, multivalued fields, query
+string and message body combinations, and many other things
+you probably don't want to think about.
+
+It doesn't get much easier: the C<CGI.pm> module automatically
+parses the input and makes each value available through the
+C<param()> function.
+
+ use CGI qw(:standard);
+
+ my $total = param( 'price' ) + param( 'shipping' );
+
+ my @items = param( 'item' ); # multiple values, same field name
+
+If you want an object-oriented approach, C<CGI.pm> can do that too.
+
+ use CGI;
+
+ my $cgi = CGI->new();
+
+ my $total = $cgi->param( 'price' ) + $cgi->param( 'shipping' );
+
+ my @items = $cgi->param( 'item' );
+
+You might also try C<CGI::Minimal> which is a lightweight version
+of the same thing. Other CGI::* modules on CPAN might work better
+for you, too.
+
+Many people try to write their own decoder (or copy one from
+another program) and then run into one of the many "gotchas"
+of the task. It's much easier and less hassle to use C<CGI.pm>.
+
+=head2 How do I check a valid mail address?
+
+(partly contributed by Aaron Sherman)
+
+This isn't as simple a question as it sounds. There are two parts:
+
+a) How do I verify that an email address is correctly formatted?
+
+b) How do I verify that an email address targets a valid recipient?
+
+Without sending mail to the address and seeing whether there's a human
+on the other end to answer you, you cannot fully answer part I<b>, but
+either the C<Email::Valid> or the C<RFC::RFC822::Address> module will do
+both part I<a> and part I<b> as far as you can in real-time.
+
+If you want to just check part I<a> to see that the address is valid
+according to the mail header standard with a simple regular expression,
+you can have problems, because there are deliverable addresses that
+aren't RFC-2822 (the latest mail header standard) compliant, and
+addresses that aren't deliverable which, are compliant. However, the
+following will match valid RFC-2822 addresses that do not have comments,
+folding whitespace, or any other obsolete or non-essential elements.
+This I<just> matches the address itself:
+
+ my $atom = qr{[a-zA-Z0-9_!#\$\%&'*+/=?\^`{}~|\-]+};
+ my $dot_atom = qr{$atom(?:\.$atom)*};
+ my $quoted = qr{"(?:\\[^\r\n]|[^\\"])*"};
+ my $local = qr{(?:$dot_atom|$quoted)};
+ my $quotedpair = qr{\\[\x00-\x09\x0B-\x0c\x0e-\x7e]};
+ my $domain_lit = qr{\[(?:$quotedpair|[\x21-\x5a\x5e-\x7e])*\]};
+ my $domain = qr{(?:$dot_atom|$domain_lit)};
+ my $addr_spec = qr{$local\@$domain};
+
+Just match an address against C</^${addr_spec}$/> to see if it follows
+the RFC2822 specification. However, because it is impossible to be
+sure that such a correctly formed address is actually the correct way
+to reach a particular person or even has a mailbox associated with it,
+you must be very careful about how you use this.
+
+Our best advice for verifying a person's mail address is to have them
+enter their address twice, just as you normally do to change a
+password. This usually weeds out typos. If both versions match, send
+mail to that address with a personal message. If you get the message
+back and they've followed your directions, you can be reasonably
+assured that it's real.
+
+A related strategy that's less open to forgery is to give them a PIN
+(personal ID number). Record the address and PIN (best that it be a
+random one) for later processing. In the mail you send, ask them to
+include the PIN in their reply. But if it bounces, or the message is
+included via a "vacation" script, it'll be there anyway. So it's
+best to ask them to mail back a slight alteration of the PIN, such as
+with the characters reversed, one added or subtracted to each digit, etc.
+
+=head2 How do I decode a MIME/BASE64 string?
+
+The C<MIME-Base64> package (available from CPAN) handles this as well as
+the MIME/QP encoding. Decoding BASE64 becomes as simple as:
+
+ use MIME::Base64;
+ $decoded = decode_base64($encoded);
+
+The C<MIME-Tools> package (available from CPAN) supports extraction with
+decoding of BASE64 encoded attachments and content directly from email
+messages.
+
+If the string to decode is short (less than 84 bytes long)
+a more direct approach is to use the C<unpack()> function's "u"
+format after minor transliterations:
+
+ tr#A-Za-z0-9+/##cd; # remove non-base64 chars
+ tr#A-Za-z0-9+/# -_#; # convert to uuencoded format
+ $len = pack("c", 32 + 0.75*length); # compute length byte
+ print unpack("u", $len . $_); # uudecode and print
+
+=head2 How do I return the user's mail address?
+
+On systems that support getpwuid, the C<< $< >> variable, and the
+C<Sys::Hostname> module (which is part of the standard perl distribution),
+you can probably try using something like this:
+
+ use Sys::Hostname;
+ $address = sprintf('%s@%s', scalar getpwuid($<), hostname);
+
+Company policies on mail address can mean that this generates addresses
+that the company's mail system will not accept, so you should ask for
+users' mail addresses when this matters. Furthermore, not all systems
+on which Perl runs are so forthcoming with this information as is Unix.
+
+The C<Mail::Util> module from CPAN (part of the C<MailTools> package) provides a
+C<mailaddress()> function that tries to guess the mail address of the user.
+It makes a more intelligent guess than the code above, using information
+given when the module was installed, but it could still be incorrect.
+Again, the best way is often just to ask the user.
+
+=head2 How do I send mail?
+
+Use the C<sendmail> program directly:
+
+ open(SENDMAIL, "|/usr/lib/sendmail -oi -t -odq")
+ or die "Can't fork for sendmail: $!\n";
+ print SENDMAIL <<"EOF";
+ From: User Originating Mail <me\@host>
+ To: Final Destination <you\@otherhost>
+ Subject: A relevant subject line
+
+ Body of the message goes here after the blank line
+ in as many lines as you like.
+ EOF
+ close(SENDMAIL) or warn "sendmail didn't close nicely";
+
+The B<-oi> option prevents C<sendmail> from interpreting a line consisting
+of a single dot as "end of message". The B<-t> option says to use the
+headers to decide who to send the message to, and B<-odq> says to put
+the message into the queue. This last option means your message won't
+be immediately delivered, so leave it out if you want immediate
+delivery.
+
+Alternate, less convenient approaches include calling C<mail> (sometimes
+called C<mailx>) directly or simply opening up port 25 have having an
+intimate conversation between just you and the remote SMTP daemon,
+probably C<sendmail>.
+
+Or you might be able use the CPAN module C<Mail::Mailer>:
+
+ use Mail::Mailer;
+
+ $mailer = Mail::Mailer->new();
+ $mailer->open({ From => $from_address,
+ To => $to_address,
+ Subject => $subject,
+ })
+ or die "Can't open: $!\n";
+ print $mailer $body;
+ $mailer->close();
+
+The C<Mail::Internet> module uses C<Net::SMTP> which is less Unix-centric than
+C<Mail::Mailer>, but less reliable. Avoid raw SMTP commands. There
+are many reasons to use a mail transport agent like C<sendmail>. These
+include queuing, MX records, and security.
+
+=head2 How do I use MIME to make an attachment to a mail message?
+
+This answer is extracted directly from the C<MIME::Lite> documentation.
+Create a multipart message (i.e., one with attachments).
+
+ use MIME::Lite;
+
+ ### Create a new multipart message:
+ $msg = MIME::Lite->new(
+ From =>'me@myhost.com',
+ To =>'you@yourhost.com',
+ Cc =>'some@other.com, some@more.com',
+ Subject =>'A message with 2 parts...',
+ Type =>'multipart/mixed'
+ );
+
+ ### Add parts (each "attach" has same arguments as "new"):
+ $msg->attach(Type =>'TEXT',
+ Data =>"Here's the GIF file you wanted"
+ );
+ $msg->attach(Type =>'image/gif',
+ Path =>'aaa000123.gif',
+ Filename =>'logo.gif'
+ );
+
+ $text = $msg->as_string;
+
+C<MIME::Lite> also includes a method for sending these things.
+
+ $msg->send;
+
+This defaults to using L<sendmail> but can be customized to use
+SMTP via L<Net::SMTP>.
+
+=head2 How do I read mail?
+
+While you could use the C<Mail::Folder> module from CPAN (part of the
+C<MailFolder> package) or the C<Mail::Internet> module from CPAN (part
+of the C<MailTools> package), often a module is overkill. Here's a
+mail sorter.
+
+ #!/usr/bin/perl
+
+ my(@msgs, @sub);
+ my $msgno = -1;
+ $/ = ''; # paragraph reads
+ while (<>) {
+ if (/^From /m) {
+ /^Subject:\s*(?:Re:\s*)*(.*)/mi;
+ $sub[++$msgno] = lc($1) || '';
+ }
+ $msgs[$msgno] .= $_;
+ }
+ for my $i (sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msgs)) {
+ print $msgs[$i];
+ }
+
+Or more succinctly,
+
+ #!/usr/bin/perl -n00
+ # bysub2 - awkish sort-by-subject
+ BEGIN { $msgno = -1 }
+ $sub[++$msgno] = (/^Subject:\s*(?:Re:\s*)*(.*)/mi)[0] if /^From/m;
+ $msg[$msgno] .= $_;
+ END { print @msg[ sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msg) ] }
+
+=head2 How do I find out my hostname, domainname, or IP address?
+X<hostname, domainname, IP address, host, domain, hostfqdn, inet_ntoa,
+gethostbyname, Socket, Net::Domain, Sys::Hostname>
+
+(contributed by brian d foy)
+
+The C<Net::Domain> module, which is part of the standard distribution starting
+in perl5.7.3, can get you the fully qualified domain name (FQDN), the host
+name, or the domain name.
+
+ use Net::Domain qw(hostname hostfqdn hostdomain);
+
+ my $host = hostfqdn();
+
+The C<Sys::Hostname> module, included in the standard distribution since
+perl5.6, can also get the hostname.
+
+ use Sys::Hostname;
+
+ $host = hostname();
+
+To get the IP address, you can use the C<gethostbyname> built-in function
+to turn the name into a number. To turn that number into the dotted octet
+form (a.b.c.d) that most people expect, use the C<inet_ntoa> function
+from the C<Socket> module, which also comes with perl.
+
+ use Socket;
+
+ my $address = inet_ntoa(
+ scalar gethostbyname( $host || 'localhost' )
+ );
+
+=head2 How do I fetch a news article or the active newsgroups?
+
+Use the C<Net::NNTP> or C<News::NNTPClient> modules, both available from CPAN.
+This can make tasks like fetching the newsgroup list as simple as
+
+ perl -MNews::NNTPClient
+ -e 'print News::NNTPClient->new->list("newsgroups")'
+
+=head2 How do I fetch/put an FTP file?
+
+C<LWP::Simple> (available from CPAN) can fetch but not put. C<Net::FTP> (also
+available from CPAN) is more complex but can put as well as fetch.
+
+=head2 How can I do RPC in Perl?
+
+(Contributed by brian d foy)
+
+Use one of the RPC modules you can find on CPAN (
+http://search.cpan.org/search?query=RPC&mode=all ).
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997-2010 Tom Christiansen, Nathan Torkington, and
+other authors as noted. All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfilter.pod b/Master/tlpkg/tlperl/lib/pods/perlfilter.pod
new file mode 100644
index 00000000000..ca5cfd9fb2e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfilter.pod
@@ -0,0 +1,587 @@
+=head1 NAME
+
+perlfilter - Source Filters
+
+=head1 DESCRIPTION
+
+This article is about a little-known feature of Perl called
+I<source filters>. Source filters alter the program text of a module
+before Perl sees it, much as a C preprocessor alters the source text of
+a C program before the compiler sees it. This article tells you more
+about what source filters are, how they work, and how to write your
+own.
+
+The original purpose of source filters was to let you encrypt your
+program source to prevent casual piracy. This isn't all they can do, as
+you'll soon learn. But first, the basics.
+
+=head1 CONCEPTS
+
+Before the Perl interpreter can execute a Perl script, it must first
+read it from a file into memory for parsing and compilation. If that
+script itself includes other scripts with a C<use> or C<require>
+statement, then each of those scripts will have to be read from their
+respective files as well.
+
+Now think of each logical connection between the Perl parser and an
+individual file as a I<source stream>. A source stream is created when
+the Perl parser opens a file, it continues to exist as the source code
+is read into memory, and it is destroyed when Perl is finished parsing
+the file. If the parser encounters a C<require> or C<use> statement in
+a source stream, a new and distinct stream is created just for that
+file.
+
+The diagram below represents a single source stream, with the flow of
+source from a Perl script file on the left into the Perl parser on the
+right. This is how Perl normally operates.
+
+ file -------> parser
+
+There are two important points to remember:
+
+=over 5
+
+=item 1.
+
+Although there can be any number of source streams in existence at any
+given time, only one will be active.
+
+=item 2.
+
+Every source stream is associated with only one file.
+
+=back
+
+A source filter is a special kind of Perl module that intercepts and
+modifies a source stream before it reaches the parser. A source filter
+changes our diagram like this:
+
+ file ----> filter ----> parser
+
+If that doesn't make much sense, consider the analogy of a command
+pipeline. Say you have a shell script stored in the compressed file
+I<trial.gz>. The simple pipeline command below runs the script without
+needing to create a temporary file to hold the uncompressed file.
+
+ gunzip -c trial.gz | sh
+
+In this case, the data flow from the pipeline can be represented as follows:
+
+ trial.gz ----> gunzip ----> sh
+
+With source filters, you can store the text of your script compressed and use a source filter to uncompress it for Perl's parser:
+
+ compressed gunzip
+ Perl program ---> source filter ---> parser
+
+=head1 USING FILTERS
+
+So how do you use a source filter in a Perl script? Above, I said that
+a source filter is just a special kind of module. Like all Perl
+modules, a source filter is invoked with a use statement.
+
+Say you want to pass your Perl source through the C preprocessor before
+execution. As it happens, the source filters distribution comes with a C
+preprocessor filter module called Filter::cpp.
+
+Below is an example program, C<cpp_test>, which makes use of this filter.
+Line numbers have been added to allow specific lines to be referenced
+easily.
+
+ 1: use Filter::cpp;
+ 2: #define TRUE 1
+ 3: $a = TRUE;
+ 4: print "a = $a\n";
+
+When you execute this script, Perl creates a source stream for the
+file. Before the parser processes any of the lines from the file, the
+source stream looks like this:
+
+ cpp_test ---------> parser
+
+Line 1, C<use Filter::cpp>, includes and installs the C<cpp> filter
+module. All source filters work this way. The use statement is compiled
+and executed at compile time, before any more of the file is read, and
+it attaches the cpp filter to the source stream behind the scenes. Now
+the data flow looks like this:
+
+ cpp_test ----> cpp filter ----> parser
+
+As the parser reads the second and subsequent lines from the source
+stream, it feeds those lines through the C<cpp> source filter before
+processing them. The C<cpp> filter simply passes each line through the
+real C preprocessor. The output from the C preprocessor is then
+inserted back into the source stream by the filter.
+
+ .-> cpp --.
+ | |
+ | |
+ | <-'
+ cpp_test ----> cpp filter ----> parser
+
+The parser then sees the following code:
+
+ use Filter::cpp;
+ $a = 1;
+ print "a = $a\n";
+
+Let's consider what happens when the filtered code includes another
+module with use:
+
+ 1: use Filter::cpp;
+ 2: #define TRUE 1
+ 3: use Fred;
+ 4: $a = TRUE;
+ 5: print "a = $a\n";
+
+The C<cpp> filter does not apply to the text of the Fred module, only
+to the text of the file that used it (C<cpp_test>). Although the use
+statement on line 3 will pass through the cpp filter, the module that
+gets included (C<Fred>) will not. The source streams look like this
+after line 3 has been parsed and before line 4 is parsed:
+
+ cpp_test ---> cpp filter ---> parser (INACTIVE)
+
+ Fred.pm ----> parser
+
+As you can see, a new stream has been created for reading the source
+from C<Fred.pm>. This stream will remain active until all of C<Fred.pm>
+has been parsed. The source stream for C<cpp_test> will still exist,
+but is inactive. Once the parser has finished reading Fred.pm, the
+source stream associated with it will be destroyed. The source stream
+for C<cpp_test> then becomes active again and the parser reads line 4
+and subsequent lines from C<cpp_test>.
+
+You can use more than one source filter on a single file. Similarly,
+you can reuse the same filter in as many files as you like.
+
+For example, if you have a uuencoded and compressed source file, it is
+possible to stack a uudecode filter and an uncompression filter like
+this:
+
+ use Filter::uudecode; use Filter::uncompress;
+ M'XL(".H<US4''V9I;F%L')Q;>7/;1I;_>_I3=&E=%:F*I"T?22Q/
+ M6]9*<IQCO*XFT"0[PL%%'Y+IG?WN^ZYN-$'J.[.JE$,20/?K=_[>
+ ...
+
+Once the first line has been processed, the flow will look like this:
+
+ file ---> uudecode ---> uncompress ---> parser
+ filter filter
+
+Data flows through filters in the same order they appear in the source
+file. The uudecode filter appeared before the uncompress filter, so the
+source file will be uudecoded before it's uncompressed.
+
+=head1 WRITING A SOURCE FILTER
+
+There are three ways to write your own source filter. You can write it
+in C, use an external program as a filter, or write the filter in Perl.
+I won't cover the first two in any great detail, so I'll get them out
+of the way first. Writing the filter in Perl is most convenient, so
+I'll devote the most space to it.
+
+=head1 WRITING A SOURCE FILTER IN C
+
+The first of the three available techniques is to write the filter
+completely in C. The external module you create interfaces directly
+with the source filter hooks provided by Perl.
+
+The advantage of this technique is that you have complete control over
+the implementation of your filter. The big disadvantage is the
+increased complexity required to write the filter - not only do you
+need to understand the source filter hooks, but you also need a
+reasonable knowledge of Perl guts. One of the few times it is worth
+going to this trouble is when writing a source scrambler. The
+C<decrypt> filter (which unscrambles the source before Perl parses it)
+included with the source filter distribution is an example of a C
+source filter (see Decryption Filters, below).
+
+
+=over 5
+
+=item B<Decryption Filters>
+
+All decryption filters work on the principle of "security through
+obscurity." Regardless of how well you write a decryption filter and
+how strong your encryption algorithm is, anyone determined enough can
+retrieve the original source code. The reason is quite simple - once
+the decryption filter has decrypted the source back to its original
+form, fragments of it will be stored in the computer's memory as Perl
+parses it. The source might only be in memory for a short period of
+time, but anyone possessing a debugger, skill, and lots of patience can
+eventually reconstruct your program.
+
+That said, there are a number of steps that can be taken to make life
+difficult for the potential cracker. The most important: Write your
+decryption filter in C and statically link the decryption module into
+the Perl binary. For further tips to make life difficult for the
+potential cracker, see the file I<decrypt.pm> in the source filters
+module.
+
+=back
+
+=head1 CREATING A SOURCE FILTER AS A SEPARATE EXECUTABLE
+
+An alternative to writing the filter in C is to create a separate
+executable in the language of your choice. The separate executable
+reads from standard input, does whatever processing is necessary, and
+writes the filtered data to standard output. C<Filter::cpp> is an
+example of a source filter implemented as a separate executable - the
+executable is the C preprocessor bundled with your C compiler.
+
+The source filter distribution includes two modules that simplify this
+task: C<Filter::exec> and C<Filter::sh>. Both allow you to run any
+external executable. Both use a coprocess to control the flow of data
+into and out of the external executable. (For details on coprocesses,
+see Stephens, W.R. "Advanced Programming in the UNIX Environment."
+Addison-Wesley, ISBN 0-210-56317-7, pages 441-445.) The difference
+between them is that C<Filter::exec> spawns the external command
+directly, while C<Filter::sh> spawns a shell to execute the external
+command. (Unix uses the Bourne shell; NT uses the cmd shell.) Spawning
+a shell allows you to make use of the shell metacharacters and
+redirection facilities.
+
+Here is an example script that uses C<Filter::sh>:
+
+ use Filter::sh 'tr XYZ PQR';
+ $a = 1;
+ print "XYZ a = $a\n";
+
+The output you'll get when the script is executed:
+
+ PQR a = 1
+
+Writing a source filter as a separate executable works fine, but a
+small performance penalty is incurred. For example, if you execute the
+small example above, a separate subprocess will be created to run the
+Unix C<tr> command. Each use of the filter requires its own subprocess.
+If creating subprocesses is expensive on your system, you might want to
+consider one of the other options for creating source filters.
+
+=head1 WRITING A SOURCE FILTER IN PERL
+
+The easiest and most portable option available for creating your own
+source filter is to write it completely in Perl. To distinguish this
+from the previous two techniques, I'll call it a Perl source filter.
+
+To help understand how to write a Perl source filter we need an example
+to study. Here is a complete source filter that performs rot13
+decoding. (Rot13 is a very simple encryption scheme used in Usenet
+postings to hide the contents of offensive posts. It moves every letter
+forward thirteen places, so that A becomes N, B becomes O, and Z
+becomes M.)
+
+
+ package Rot13;
+
+ use Filter::Util::Call;
+
+ sub import {
+ my ($type) = @_;
+ my ($ref) = [];
+ filter_add(bless $ref);
+ }
+
+ sub filter {
+ my ($self) = @_;
+ my ($status);
+
+ tr/n-za-mN-ZA-M/a-zA-Z/
+ if ($status = filter_read()) > 0;
+ $status;
+ }
+
+ 1;
+
+All Perl source filters are implemented as Perl classes and have the
+same basic structure as the example above.
+
+First, we include the C<Filter::Util::Call> module, which exports a
+number of functions into your filter's namespace. The filter shown
+above uses two of these functions, C<filter_add()> and
+C<filter_read()>.
+
+Next, we create the filter object and associate it with the source
+stream by defining the C<import> function. If you know Perl well
+enough, you know that C<import> is called automatically every time a
+module is included with a use statement. This makes C<import> the ideal
+place to both create and install a filter object.
+
+In the example filter, the object (C<$ref>) is blessed just like any
+other Perl object. Our example uses an anonymous array, but this isn't
+a requirement. Because this example doesn't need to store any context
+information, we could have used a scalar or hash reference just as
+well. The next section demonstrates context data.
+
+The association between the filter object and the source stream is made
+with the C<filter_add()> function. This takes a filter object as a
+parameter (C<$ref> in this case) and installs it in the source stream.
+
+Finally, there is the code that actually does the filtering. For this
+type of Perl source filter, all the filtering is done in a method
+called C<filter()>. (It is also possible to write a Perl source filter
+using a closure. See the C<Filter::Util::Call> manual page for more
+details.) It's called every time the Perl parser needs another line of
+source to process. The C<filter()> method, in turn, reads lines from
+the source stream using the C<filter_read()> function.
+
+If a line was available from the source stream, C<filter_read()>
+returns a status value greater than zero and appends the line to C<$_>.
+A status value of zero indicates end-of-file, less than zero means an
+error. The filter function itself is expected to return its status in
+the same way, and put the filtered line it wants written to the source
+stream in C<$_>. The use of C<$_> accounts for the brevity of most Perl
+source filters.
+
+In order to make use of the rot13 filter we need some way of encoding
+the source file in rot13 format. The script below, C<mkrot13>, does
+just that.
+
+ die "usage mkrot13 filename\n" unless @ARGV;
+ my $in = $ARGV[0];
+ my $out = "$in.tmp";
+ open(IN, "<$in") or die "Cannot open file $in: $!\n";
+ open(OUT, ">$out") or die "Cannot open file $out: $!\n";
+
+ print OUT "use Rot13;\n";
+ while (<IN>) {
+ tr/a-zA-Z/n-za-mN-ZA-M/;
+ print OUT;
+ }
+
+ close IN;
+ close OUT;
+ unlink $in;
+ rename $out, $in;
+
+If we encrypt this with C<mkrot13>:
+
+ print " hello fred \n";
+
+the result will be this:
+
+ use Rot13;
+ cevag "uryyb serq\a";
+
+Running it produces this output:
+
+ hello fred
+
+=head1 USING CONTEXT: THE DEBUG FILTER
+
+The rot13 example was a trivial example. Here's another demonstration
+that shows off a few more features.
+
+Say you wanted to include a lot of debugging code in your Perl script
+during development, but you didn't want it available in the released
+product. Source filters offer a solution. In order to keep the example
+simple, let's say you wanted the debugging output to be controlled by
+an environment variable, C<DEBUG>. Debugging code is enabled if the
+variable exists, otherwise it is disabled.
+
+Two special marker lines will bracket debugging code, like this:
+
+ ## DEBUG_BEGIN
+ if ($year > 1999) {
+ warn "Debug: millennium bug in year $year\n";
+ }
+ ## DEBUG_END
+
+When the C<DEBUG> environment variable exists, the filter ensures that
+Perl parses only the code between the C<DEBUG_BEGIN> and C<DEBUG_END>
+markers. That means that when C<DEBUG> does exist, the code above
+should be passed through the filter unchanged. The marker lines can
+also be passed through as-is, because the Perl parser will see them as
+comment lines. When C<DEBUG> isn't set, we need a way to disable the
+debug code. A simple way to achieve that is to convert the lines
+between the two markers into comments:
+
+ ## DEBUG_BEGIN
+ #if ($year > 1999) {
+ # warn "Debug: millennium bug in year $year\n";
+ #}
+ ## DEBUG_END
+
+Here is the complete Debug filter:
+
+ package Debug;
+
+ use strict;
+ use warnings;
+ use Filter::Util::Call;
+
+ use constant TRUE => 1;
+ use constant FALSE => 0;
+
+ sub import {
+ my ($type) = @_;
+ my (%context) = (
+ Enabled => defined $ENV{DEBUG},
+ InTraceBlock => FALSE,
+ Filename => (caller)[1],
+ LineNo => 0,
+ LastBegin => 0,
+ );
+ filter_add(bless \%context);
+ }
+
+ sub Die {
+ my ($self) = shift;
+ my ($message) = shift;
+ my ($line_no) = shift || $self->{LastBegin};
+ die "$message at $self->{Filename} line $line_no.\n"
+ }
+
+ sub filter {
+ my ($self) = @_;
+ my ($status);
+ $status = filter_read();
+ ++ $self->{LineNo};
+
+ # deal with EOF/error first
+ if ($status <= 0) {
+ $self->Die("DEBUG_BEGIN has no DEBUG_END")
+ if $self->{InTraceBlock};
+ return $status;
+ }
+
+ if ($self->{InTraceBlock}) {
+ if (/^\s*##\s*DEBUG_BEGIN/ ) {
+ $self->Die("Nested DEBUG_BEGIN", $self->{LineNo})
+ } elsif (/^\s*##\s*DEBUG_END/) {
+ $self->{InTraceBlock} = FALSE;
+ }
+
+ # comment out the debug lines when the filter is disabled
+ s/^/#/ if ! $self->{Enabled};
+ } elsif ( /^\s*##\s*DEBUG_BEGIN/ ) {
+ $self->{InTraceBlock} = TRUE;
+ $self->{LastBegin} = $self->{LineNo};
+ } elsif ( /^\s*##\s*DEBUG_END/ ) {
+ $self->Die("DEBUG_END has no DEBUG_BEGIN", $self->{LineNo});
+ }
+ return $status;
+ }
+
+ 1;
+
+The big difference between this filter and the previous example is the
+use of context data in the filter object. The filter object is based on
+a hash reference, and is used to keep various pieces of context
+information between calls to the filter function. All but two of the
+hash fields are used for error reporting. The first of those two,
+Enabled, is used by the filter to determine whether the debugging code
+should be given to the Perl parser. The second, InTraceBlock, is true
+when the filter has encountered a C<DEBUG_BEGIN> line, but has not yet
+encountered the following C<DEBUG_END> line.
+
+If you ignore all the error checking that most of the code does, the
+essence of the filter is as follows:
+
+ sub filter {
+ my ($self) = @_;
+ my ($status);
+ $status = filter_read();
+
+ # deal with EOF/error first
+ return $status if $status <= 0;
+ if ($self->{InTraceBlock}) {
+ if (/^\s*##\s*DEBUG_END/) {
+ $self->{InTraceBlock} = FALSE
+ }
+
+ # comment out debug lines when the filter is disabled
+ s/^/#/ if ! $self->{Enabled};
+ } elsif ( /^\s*##\s*DEBUG_BEGIN/ ) {
+ $self->{InTraceBlock} = TRUE;
+ }
+ return $status;
+ }
+
+Be warned: just as the C-preprocessor doesn't know C, the Debug filter
+doesn't know Perl. It can be fooled quite easily:
+
+ print <<EOM;
+ ##DEBUG_BEGIN
+ EOM
+
+Such things aside, you can see that a lot can be achieved with a modest
+amount of code.
+
+=head1 CONCLUSION
+
+You now have better understanding of what a source filter is, and you
+might even have a possible use for them. If you feel like playing with
+source filters but need a bit of inspiration, here are some extra
+features you could add to the Debug filter.
+
+First, an easy one. Rather than having debugging code that is
+all-or-nothing, it would be much more useful to be able to control
+which specific blocks of debugging code get included. Try extending the
+syntax for debug blocks to allow each to be identified. The contents of
+the C<DEBUG> environment variable can then be used to control which
+blocks get included.
+
+Once you can identify individual blocks, try allowing them to be
+nested. That isn't difficult either.
+
+Here is an interesting idea that doesn't involve the Debug filter.
+Currently Perl subroutines have fairly limited support for formal
+parameter lists. You can specify the number of parameters and their
+type, but you still have to manually take them out of the C<@_> array
+yourself. Write a source filter that allows you to have a named
+parameter list. Such a filter would turn this:
+
+ sub MySub ($first, $second, @rest) { ... }
+
+into this:
+
+ sub MySub($$@) {
+ my ($first) = shift;
+ my ($second) = shift;
+ my (@rest) = @_;
+ ...
+ }
+
+Finally, if you feel like a real challenge, have a go at writing a
+full-blown Perl macro preprocessor as a source filter. Borrow the
+useful features from the C preprocessor and any other macro processors
+you know. The tricky bit will be choosing how much knowledge of Perl's
+syntax you want your filter to have.
+
+=head1 THINGS TO LOOK OUT FOR
+
+=over 5
+
+=item Some Filters Clobber the C<DATA> Handle
+
+Some source filters use the C<DATA> handle to read the calling program.
+When using these source filters you cannot rely on this handle, nor expect
+any particular kind of behavior when operating on it. Filters based on
+Filter::Util::Call (and therefore Filter::Simple) do not alter the C<DATA>
+filehandle.
+
+=back
+
+=head1 REQUIREMENTS
+
+The Source Filters distribution is available on CPAN, in
+
+ CPAN/modules/by-module/Filter
+
+Starting from Perl 5.8 Filter::Util::Call (the core part of the
+Source Filters distribution) is part of the standard Perl distribution.
+Also included is a friendlier interface called Filter::Simple, by
+Damian Conway.
+
+=head1 AUTHOR
+
+Paul Marquess E<lt>Paul.Marquess@btinternet.comE<gt>
+
+=head1 Copyrights
+
+This article originally appeared in The Perl Journal #11, and is
+copyright 1998 The Perl Journal. It appears courtesy of Jon Orwant and
+The Perl Journal. This document may be distributed under the same terms
+as Perl itself.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfork.pod b/Master/tlpkg/tlperl/lib/pods/perlfork.pod
new file mode 100644
index 00000000000..48d65ed4c58
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfork.pod
@@ -0,0 +1,323 @@
+=head1 NAME
+
+perlfork - Perl's fork() emulation
+
+=head1 SYNOPSIS
+
+ NOTE: As of the 5.8.0 release, fork() emulation has considerably
+ matured. However, there are still a few known bugs and differences
+ from real fork() that might affect you. See the "BUGS" and
+ "CAVEATS AND LIMITATIONS" sections below.
+
+Perl provides a fork() keyword that corresponds to the Unix system call
+of the same name. On most Unix-like platforms where the fork() system
+call is available, Perl's fork() simply calls it.
+
+On some platforms such as Windows where the fork() system call is not
+available, Perl can be built to emulate fork() at the interpreter level.
+While the emulation is designed to be as compatible as possible with the
+real fork() at the level of the Perl program, there are certain
+important differences that stem from the fact that all the pseudo child
+"processes" created this way live in the same real process as far as the
+operating system is concerned.
+
+This document provides a general overview of the capabilities and
+limitations of the fork() emulation. Note that the issues discussed here
+are not applicable to platforms where a real fork() is available and Perl
+has been configured to use it.
+
+=head1 DESCRIPTION
+
+The fork() emulation is implemented at the level of the Perl interpreter.
+What this means in general is that running fork() will actually clone the
+running interpreter and all its state, and run the cloned interpreter in
+a separate thread, beginning execution in the new thread just after the
+point where the fork() was called in the parent. We will refer to the
+thread that implements this child "process" as the pseudo-process.
+
+To the Perl program that called fork(), all this is designed to be
+transparent. The parent returns from the fork() with a pseudo-process
+ID that can be subsequently used in any process manipulation functions;
+the child returns from the fork() with a value of C<0> to signify that
+it is the child pseudo-process.
+
+=head2 Behavior of other Perl features in forked pseudo-processes
+
+Most Perl features behave in a natural way within pseudo-processes.
+
+=over 8
+
+=item $$ or $PROCESS_ID
+
+This special variable is correctly set to the pseudo-process ID.
+It can be used to identify pseudo-processes within a particular
+session. Note that this value is subject to recycling if any
+pseudo-processes are launched after others have been wait()-ed on.
+
+=item %ENV
+
+Each pseudo-process maintains its own virtual environment. Modifications
+to %ENV affect the virtual environment, and are only visible within that
+pseudo-process, and in any processes (or pseudo-processes) launched from
+it.
+
+=item chdir() and all other builtins that accept filenames
+
+Each pseudo-process maintains its own virtual idea of the current directory.
+Modifications to the current directory using chdir() are only visible within
+that pseudo-process, and in any processes (or pseudo-processes) launched from
+it. All file and directory accesses from the pseudo-process will correctly
+map the virtual working directory to the real working directory appropriately.
+
+=item wait() and waitpid()
+
+wait() and waitpid() can be passed a pseudo-process ID returned by fork().
+These calls will properly wait for the termination of the pseudo-process
+and return its status.
+
+=item kill()
+
+kill() can be used to terminate a pseudo-process by passing it the ID returned
+by fork(). This should not be used except under dire circumstances, because
+the operating system may not guarantee integrity of the process resources
+when a running thread is terminated. Note that using kill() on a
+pseudo-process() may typically cause memory leaks, because the thread that
+implements the pseudo-process does not get a chance to clean up its resources.
+
+=item exec()
+
+Calling exec() within a pseudo-process actually spawns the requested
+executable in a separate process and waits for it to complete before
+exiting with the same exit status as that process. This means that the
+process ID reported within the running executable will be different from
+what the earlier Perl fork() might have returned. Similarly, any process
+manipulation functions applied to the ID returned by fork() will affect the
+waiting pseudo-process that called exec(), not the real process it is
+waiting for after the exec().
+
+When exec() is called inside a pseudo-process then DESTROY methods and
+END blocks will still be called after the external process returns.
+
+=item exit()
+
+exit() always exits just the executing pseudo-process, after automatically
+wait()-ing for any outstanding child pseudo-processes. Note that this means
+that the process as a whole will not exit unless all running pseudo-processes
+have exited. See below for some limitations with open filehandles.
+
+=item Open handles to files, directories and network sockets
+
+All open handles are dup()-ed in pseudo-processes, so that closing
+any handles in one process does not affect the others. See below for
+some limitations.
+
+=back
+
+=head2 Resource limits
+
+In the eyes of the operating system, pseudo-processes created via the fork()
+emulation are simply threads in the same process. This means that any
+process-level limits imposed by the operating system apply to all
+pseudo-processes taken together. This includes any limits imposed by the
+operating system on the number of open file, directory and socket handles,
+limits on disk space usage, limits on memory size, limits on CPU utilization
+etc.
+
+=head2 Killing the parent process
+
+If the parent process is killed (either using Perl's kill() builtin, or
+using some external means) all the pseudo-processes are killed as well,
+and the whole process exits.
+
+=head2 Lifetime of the parent process and pseudo-processes
+
+During the normal course of events, the parent process and every
+pseudo-process started by it will wait for their respective pseudo-children
+to complete before they exit. This means that the parent and every
+pseudo-child created by it that is also a pseudo-parent will only exit
+after their pseudo-children have exited.
+
+A way to mark a pseudo-processes as running detached from their parent (so
+that the parent would not have to wait() for them if it doesn't want to)
+will be provided in future.
+
+=head2 CAVEATS AND LIMITATIONS
+
+=over 8
+
+=item BEGIN blocks
+
+The fork() emulation will not work entirely correctly when called from
+within a BEGIN block. The forked copy will run the contents of the
+BEGIN block, but will not continue parsing the source stream after the
+BEGIN block. For example, consider the following code:
+
+ BEGIN {
+ fork and exit; # fork child and exit the parent
+ print "inner\n";
+ }
+ print "outer\n";
+
+This will print:
+
+ inner
+
+rather than the expected:
+
+ inner
+ outer
+
+This limitation arises from fundamental technical difficulties in
+cloning and restarting the stacks used by the Perl parser in the
+middle of a parse.
+
+=item Open filehandles
+
+Any filehandles open at the time of the fork() will be dup()-ed. Thus,
+the files can be closed independently in the parent and child, but beware
+that the dup()-ed handles will still share the same seek pointer. Changing
+the seek position in the parent will change it in the child and vice-versa.
+One can avoid this by opening files that need distinct seek pointers
+separately in the child.
+
+On some operating systems, notably Solaris and Unixware, calling C<exit()>
+from a child process will flush and close open filehandles in the parent,
+thereby corrupting the filehandles. On these systems, calling C<_exit()>
+is suggested instead. C<_exit()> is available in Perl through the
+C<POSIX> module. Please consult your systems manpages for more information
+on this.
+
+=item Forking pipe open() not yet implemented
+
+The C<open(FOO, "|-")> and C<open(BAR, "-|")> constructs are not yet
+implemented. This limitation can be easily worked around in new code
+by creating a pipe explicitly. The following example shows how to
+write to a forked child:
+
+ # simulate open(FOO, "|-")
+ sub pipe_to_fork ($) {
+ my $parent = shift;
+ pipe my $child, $parent or die;
+ my $pid = fork();
+ die "fork() failed: $!" unless defined $pid;
+ if ($pid) {
+ close $child;
+ }
+ else {
+ close $parent;
+ open(STDIN, "<&=" . fileno($child)) or die;
+ }
+ $pid;
+ }
+
+ if (pipe_to_fork('FOO')) {
+ # parent
+ print FOO "pipe_to_fork\n";
+ close FOO;
+ }
+ else {
+ # child
+ while (<STDIN>) { print; }
+ exit(0);
+ }
+
+And this one reads from the child:
+
+ # simulate open(FOO, "-|")
+ sub pipe_from_fork ($) {
+ my $parent = shift;
+ pipe $parent, my $child or die;
+ my $pid = fork();
+ die "fork() failed: $!" unless defined $pid;
+ if ($pid) {
+ close $child;
+ }
+ else {
+ close $parent;
+ open(STDOUT, ">&=" . fileno($child)) or die;
+ }
+ $pid;
+ }
+
+ if (pipe_from_fork('BAR')) {
+ # parent
+ while (<BAR>) { print; }
+ close BAR;
+ }
+ else {
+ # child
+ print "pipe_from_fork\n";
+ exit(0);
+ }
+
+Forking pipe open() constructs will be supported in future.
+
+=item Global state maintained by XSUBs
+
+External subroutines (XSUBs) that maintain their own global state may
+not work correctly. Such XSUBs will either need to maintain locks to
+protect simultaneous access to global data from different pseudo-processes,
+or maintain all their state on the Perl symbol table, which is copied
+naturally when fork() is called. A callback mechanism that provides
+extensions an opportunity to clone their state will be provided in the
+near future.
+
+=item Interpreter embedded in larger application
+
+The fork() emulation may not behave as expected when it is executed in an
+application which embeds a Perl interpreter and calls Perl APIs that can
+evaluate bits of Perl code. This stems from the fact that the emulation
+only has knowledge about the Perl interpreter's own data structures and
+knows nothing about the containing application's state. For example, any
+state carried on the application's own call stack is out of reach.
+
+=item Thread-safety of extensions
+
+Since the fork() emulation runs code in multiple threads, extensions
+calling into non-thread-safe libraries may not work reliably when
+calling fork(). As Perl's threading support gradually becomes more
+widely adopted even on platforms with a native fork(), such extensions
+are expected to be fixed for thread-safety.
+
+=back
+
+=head1 BUGS
+
+=over 8
+
+=item *
+
+Having pseudo-process IDs be negative integers breaks down for the integer
+C<-1> because the wait() and waitpid() functions treat this number as
+being special. The tacit assumption in the current implementation is that
+the system never allocates a thread ID of C<1> for user threads. A better
+representation for pseudo-process IDs will be implemented in future.
+
+=item *
+
+In certain cases, the OS-level handles created by the pipe(), socket(),
+and accept() operators are apparently not duplicated accurately in
+pseudo-processes. This only happens in some situations, but where it
+does happen, it may result in deadlocks between the read and write ends
+of pipe handles, or inability to send or receive data across socket
+handles.
+
+=item *
+
+This document may be incomplete in some respects.
+
+=back
+
+=head1 AUTHOR
+
+Support for concurrent interpreters and the fork() emulation was implemented
+by ActiveState, with funding from Microsoft Corporation.
+
+This document is authored and maintained by Gurusamy Sarathy
+E<lt>gsar@activestate.comE<gt>.
+
+=head1 SEE ALSO
+
+L<perlfunc/"fork">, L<perlipc>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlform.pod b/Master/tlpkg/tlperl/lib/pods/perlform.pod
new file mode 100644
index 00000000000..3cfa1b768d0
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlform.pod
@@ -0,0 +1,459 @@
+=head1 NAME
+X<format> X<report> X<chart>
+
+perlform - Perl formats
+
+=head1 DESCRIPTION
+
+Perl has a mechanism to help you generate simple reports and charts. To
+facilitate this, Perl helps you code up your output page close to how it
+will look when it's printed. It can keep track of things like how many
+lines are on a page, what page you're on, when to print page headers,
+etc. Keywords are borrowed from FORTRAN: format() to declare and write()
+to execute; see their entries in L<perlfunc>. Fortunately, the layout is
+much more legible, more like BASIC's PRINT USING statement. Think of it
+as a poor man's nroff(1).
+X<nroff>
+
+Formats, like packages and subroutines, are declared rather than
+executed, so they may occur at any point in your program. (Usually it's
+best to keep them all together though.) They have their own namespace
+apart from all the other "types" in Perl. This means that if you have a
+function named "Foo", it is not the same thing as having a format named
+"Foo". However, the default name for the format associated with a given
+filehandle is the same as the name of the filehandle. Thus, the default
+format for STDOUT is named "STDOUT", and the default format for filehandle
+TEMP is named "TEMP". They just look the same. They aren't.
+
+Output record formats are declared as follows:
+
+ format NAME =
+ FORMLIST
+ .
+
+If the name is omitted, format "STDOUT" is defined. A single "." in
+column 1 is used to terminate a format. FORMLIST consists of a sequence
+of lines, each of which may be one of three types:
+
+=over 4
+
+=item 1.
+
+A comment, indicated by putting a '#' in the first column.
+
+=item 2.
+
+A "picture" line giving the format for one output line.
+
+=item 3.
+
+An argument line supplying values to plug into the previous picture line.
+
+=back
+
+Picture lines contain output field definitions, intermingled with
+literal text. These lines do not undergo any kind of variable interpolation.
+Field definitions are made up from a set of characters, for starting and
+extending a field to its desired width. This is the complete set of
+characters for field definitions:
+X<format, picture line>
+X<@> X<^> X<< < >> X<< | >> X<< > >> X<#> X<0> X<.> X<...>
+X<@*> X<^*> X<~> X<~~>
+
+ @ start of regular field
+ ^ start of special field
+ < pad character for left justification
+ | pad character for centering
+ > pad character for right justification
+ # pad character for a right justified numeric field
+ 0 instead of first #: pad number with leading zeroes
+ . decimal point within a numeric field
+ ... terminate a text field, show "..." as truncation evidence
+ @* variable width field for a multi-line value
+ ^* variable width field for next line of a multi-line value
+ ~ suppress line with all fields empty
+ ~~ repeat line until all fields are exhausted
+
+Each field in a picture line starts with either "@" (at) or "^" (caret),
+indicating what we'll call, respectively, a "regular" or "special" field.
+The choice of pad characters determines whether a field is textual or
+numeric. The tilde operators are not part of a field. Let's look at
+the various possibilities in detail.
+
+
+=head2 Text Fields
+X<format, text field>
+
+The length of the field is supplied by padding out the field with multiple
+"E<lt>", "E<gt>", or "|" characters to specify a non-numeric field with,
+respectively, left justification, right justification, or centering.
+For a regular field, the value (up to the first newline) is taken and
+printed according to the selected justification, truncating excess characters.
+If you terminate a text field with "...", three dots will be shown if
+the value is truncated. A special text field may be used to do rudimentary
+multi-line text block filling; see L</Using Fill Mode> for details.
+
+ Example:
+ format STDOUT =
+ @<<<<<< @|||||| @>>>>>>
+ "left", "middle", "right"
+ .
+ Output:
+ left middle right
+
+
+=head2 Numeric Fields
+X<#> X<format, numeric field>
+
+Using "#" as a padding character specifies a numeric field, with
+right justification. An optional "." defines the position of the
+decimal point. With a "0" (zero) instead of the first "#", the
+formatted number will be padded with leading zeroes if necessary.
+A special numeric field is blanked out if the value is undefined.
+If the resulting value would exceed the width specified the field is
+filled with "#" as overflow evidence.
+
+ Example:
+ format STDOUT =
+ @### @.### @##.### @### @### ^####
+ 42, 3.1415, undef, 0, 10000, undef
+ .
+ Output:
+ 42 3.142 0.000 0 ####
+
+
+=head2 The Field @* for Variable Width Multi-Line Text
+X<@*>
+
+The field "@*" can be used for printing multi-line, nontruncated
+values; it should (but need not) appear by itself on a line. A final
+line feed is chomped off, but all other characters are emitted verbatim.
+
+
+=head2 The Field ^* for Variable Width One-line-at-a-time Text
+X<^*>
+
+Like "@*", this is a variable width field. The value supplied must be a
+scalar variable. Perl puts the first line (up to the first "\n") of the
+text into the field, and then chops off the front of the string so that
+the next time the variable is referenced, more of the text can be printed.
+The variable will I<not> be restored.
+
+ Example:
+ $text = "line 1\nline 2\nline 3";
+ format STDOUT =
+ Text: ^*
+ $text
+ ~~ ^*
+ $text
+ .
+ Output:
+ Text: line 1
+ line 2
+ line 3
+
+
+=head2 Specifying Values
+X<format, specifying values>
+
+The values are specified on the following format line in the same order as
+the picture fields. The expressions providing the values must be
+separated by commas. They are all evaluated in a list context
+before the line is processed, so a single list expression could produce
+multiple list elements. The expressions may be spread out to more than
+one line if enclosed in braces. If so, the opening brace must be the first
+token on the first line. If an expression evaluates to a number with a
+decimal part, and if the corresponding picture specifies that the decimal
+part should appear in the output (that is, any picture except multiple "#"
+characters B<without> an embedded "."), the character used for the decimal
+point is B<always> determined by the current LC_NUMERIC locale. This
+means that, if, for example, the run-time environment happens to specify a
+German locale, "," will be used instead of the default ".". See
+L<perllocale> and L<"WARNINGS"> for more information.
+
+
+=head2 Using Fill Mode
+X<format, fill mode>
+
+On text fields the caret enables a kind of fill mode. Instead of an
+arbitrary expression, the value supplied must be a scalar variable
+that contains a text string. Perl puts the next portion of the text into
+the field, and then chops off the front of the string so that the next time
+the variable is referenced, more of the text can be printed. (Yes, this
+means that the variable itself is altered during execution of the write()
+call, and is not restored.) The next portion of text is determined by
+a crude line breaking algorithm. You may use the carriage return character
+(C<\r>) to force a line break. You can change which characters are legal
+to break on by changing the variable C<$:> (that's
+$FORMAT_LINE_BREAK_CHARACTERS if you're using the English module) to a
+list of the desired characters.
+
+Normally you would use a sequence of fields in a vertical stack associated
+with the same scalar variable to print out a block of text. You might wish
+to end the final field with the text "...", which will appear in the output
+if the text was too long to appear in its entirety.
+
+
+=head2 Suppressing Lines Where All Fields Are Void
+X<format, suppressing lines>
+
+Using caret fields can produce lines where all fields are blank. You can
+suppress such lines by putting a "~" (tilde) character anywhere in the
+line. The tilde will be translated to a space upon output.
+
+
+=head2 Repeating Format Lines
+X<format, repeating lines>
+
+If you put two contiguous tilde characters "~~" anywhere into a line,
+the line will be repeated until all the fields on the line are exhausted,
+i.e. undefined. For special (caret) text fields this will occur sooner or
+later, but if you use a text field of the at variety, the expression you
+supply had better not give the same value every time forever! (C<shift(@f)>
+is a simple example that would work.) Don't use a regular (at) numeric
+field in such lines, because it will never go blank.
+
+
+=head2 Top of Form Processing
+X<format, top of form> X<top> X<header>
+
+Top-of-form processing is by default handled by a format with the
+same name as the current filehandle with "_TOP" concatenated to it.
+It's triggered at the top of each page. See L<perlfunc/write>.
+
+Examples:
+
+ # a report on the /etc/passwd file
+ format STDOUT_TOP =
+ Passwd File
+ Name Login Office Uid Gid Home
+ ------------------------------------------------------------------
+ .
+ format STDOUT =
+ @<<<<<<<<<<<<<<<<<< @||||||| @<<<<<<@>>>> @>>>> @<<<<<<<<<<<<<<<<<
+ $name, $login, $office,$uid,$gid, $home
+ .
+
+
+ # a report from a bug report form
+ format STDOUT_TOP =
+ Bug Reports
+ @<<<<<<<<<<<<<<<<<<<<<<< @||| @>>>>>>>>>>>>>>>>>>>>>>>
+ $system, $%, $date
+ ------------------------------------------------------------------
+ .
+ format STDOUT =
+ Subject: @<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $subject
+ Index: @<<<<<<<<<<<<<<<<<<<<<<<<<<<< ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $index, $description
+ Priority: @<<<<<<<<<< Date: @<<<<<<< ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $priority, $date, $description
+ From: @<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $from, $description
+ Assigned to: @<<<<<<<<<<<<<<<<<<<<<< ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $programmer, $description
+ ~ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $description
+ ~ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $description
+ ~ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $description
+ ~ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $description
+ ~ ^<<<<<<<<<<<<<<<<<<<<<<<...
+ $description
+ .
+
+It is possible to intermix print()s with write()s on the same output
+channel, but you'll have to handle C<$-> (C<$FORMAT_LINES_LEFT>)
+yourself.
+
+=head2 Format Variables
+X<format variables>
+X<format, variables>
+
+The current format name is stored in the variable C<$~> (C<$FORMAT_NAME>),
+and the current top of form format name is in C<$^> (C<$FORMAT_TOP_NAME>).
+The current output page number is stored in C<$%> (C<$FORMAT_PAGE_NUMBER>),
+and the number of lines on the page is in C<$=> (C<$FORMAT_LINES_PER_PAGE>).
+Whether to autoflush output on this handle is stored in C<$|>
+(C<$OUTPUT_AUTOFLUSH>). The string output before each top of page (except
+the first) is stored in C<$^L> (C<$FORMAT_FORMFEED>). These variables are
+set on a per-filehandle basis, so you'll need to select() into a different
+one to affect them:
+
+ select((select(OUTF),
+ $~ = "My_Other_Format",
+ $^ = "My_Top_Format"
+ )[0]);
+
+Pretty ugly, eh? It's a common idiom though, so don't be too surprised
+when you see it. You can at least use a temporary variable to hold
+the previous filehandle: (this is a much better approach in general,
+because not only does legibility improve, you now have intermediary
+stage in the expression to single-step the debugger through):
+
+ $ofh = select(OUTF);
+ $~ = "My_Other_Format";
+ $^ = "My_Top_Format";
+ select($ofh);
+
+If you use the English module, you can even read the variable names:
+
+ use English '-no_match_vars';
+ $ofh = select(OUTF);
+ $FORMAT_NAME = "My_Other_Format";
+ $FORMAT_TOP_NAME = "My_Top_Format";
+ select($ofh);
+
+But you still have those funny select()s. So just use the FileHandle
+module. Now, you can access these special variables using lowercase
+method names instead:
+
+ use FileHandle;
+ format_name OUTF "My_Other_Format";
+ format_top_name OUTF "My_Top_Format";
+
+Much better!
+
+=head1 NOTES
+
+Because the values line may contain arbitrary expressions (for at fields,
+not caret fields), you can farm out more sophisticated processing
+to other functions, like sprintf() or one of your own. For example:
+
+ format Ident =
+ @<<<<<<<<<<<<<<<
+ &commify($n)
+ .
+
+To get a real at or caret into the field, do this:
+
+ format Ident =
+ I have an @ here.
+ "@"
+ .
+
+To center a whole line of text, do something like this:
+
+ format Ident =
+ @|||||||||||||||||||||||||||||||||||||||||||||||
+ "Some text line"
+ .
+
+There is no builtin way to say "float this to the right hand side
+of the page, however wide it is." You have to specify where it goes.
+The truly desperate can generate their own format on the fly, based
+on the current number of columns, and then eval() it:
+
+ $format = "format STDOUT = \n"
+ . '^' . '<' x $cols . "\n"
+ . '$entry' . "\n"
+ . "\t^" . "<" x ($cols-8) . "~~\n"
+ . '$entry' . "\n"
+ . ".\n";
+ print $format if $Debugging;
+ eval $format;
+ die $@ if $@;
+
+Which would generate a format looking something like this:
+
+ format STDOUT =
+ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+ $entry
+ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<~~
+ $entry
+ .
+
+Here's a little program that's somewhat like fmt(1):
+
+ format =
+ ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ~~
+ $_
+
+ .
+
+ $/ = '';
+ while (<>) {
+ s/\s*\n\s*/ /g;
+ write;
+ }
+
+=head2 Footers
+X<format, footer> X<footer>
+
+While $FORMAT_TOP_NAME contains the name of the current header format,
+there is no corresponding mechanism to automatically do the same thing
+for a footer. Not knowing how big a format is going to be until you
+evaluate it is one of the major problems. It's on the TODO list.
+
+Here's one strategy: If you have a fixed-size footer, you can get footers
+by checking $FORMAT_LINES_LEFT before each write() and print the footer
+yourself if necessary.
+
+Here's another strategy: Open a pipe to yourself, using C<open(MYSELF, "|-")>
+(see L<perlfunc/open()>) and always write() to MYSELF instead of STDOUT.
+Have your child process massage its STDIN to rearrange headers and footers
+however you like. Not very convenient, but doable.
+
+=head2 Accessing Formatting Internals
+X<format, internals>
+
+For low-level access to the formatting mechanism. you may use formline()
+and access C<$^A> (the $ACCUMULATOR variable) directly.
+
+For example:
+
+ $str = formline <<'END', 1,2,3;
+ @<<< @||| @>>>
+ END
+
+ print "Wow, I just stored `$^A' in the accumulator!\n";
+
+Or to make an swrite() subroutine, which is to write() what sprintf()
+is to printf(), do this:
+
+ use Carp;
+ sub swrite {
+ croak "usage: swrite PICTURE ARGS" unless @_;
+ my $format = shift;
+ $^A = "";
+ formline($format,@_);
+ return $^A;
+ }
+
+ $string = swrite(<<'END', 1, 2, 3);
+ Check me out
+ @<<< @||| @>>>
+ END
+ print $string;
+
+=head1 WARNINGS
+
+The lone dot that ends a format can also prematurely end a mail
+message passing through a misconfigured Internet mailer (and based on
+experience, such misconfiguration is the rule, not the exception). So
+when sending format code through mail, you should indent it so that
+the format-ending dot is not on the left margin; this will prevent
+SMTP cutoff.
+
+Lexical variables (declared with "my") are not visible within a
+format unless the format is declared within the scope of the lexical
+variable. (They weren't visible at all before version 5.001.)
+
+Formats are the only part of Perl that unconditionally use information
+from a program's locale; if a program's environment specifies an
+LC_NUMERIC locale, it is always used to specify the decimal point
+character in formatted output. Perl ignores all other aspects of locale
+handling unless the C<use locale> pragma is in effect. Formatted output
+cannot be controlled by C<use locale> because the pragma is tied to the
+block structure of the program, and, for historical reasons, formats
+exist outside that block structure. See L<perllocale> for further
+discussion of locale handling.
+
+Within strings that are to be displayed in a fixed length text field,
+each control character is substituted by a space. (But remember the
+special meaning of C<\r> when using fill mode.) This is done to avoid
+misalignment when control characters "disappear" on some output media.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfreebsd.pod b/Master/tlpkg/tlperl/lib/pods/perlfreebsd.pod
new file mode 100644
index 00000000000..77c297bec6d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfreebsd.pod
@@ -0,0 +1,47 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.freebsd - Perl version 5 on FreeBSD systems
+
+=head1 DESCRIPTION
+
+This document describes various features of FreeBSD that will affect how Perl
+version 5 (hereafter just Perl) is compiled and/or runs.
+
+=head2 FreeBSD core dumps from readdir_r with ithreads
+
+When perl is configured to use ithreads, it will use re-entrant library calls
+in preference to non-re-entrant versions. There is a bug in FreeBSD's
+C<readdir_r> function in versions 4.5 and earlier that can cause a SEGV when
+reading large directories. A patch for FreeBSD libc is available
+(see http://www.freebsd.org/cgi/query-pr.cgi?pr=misc/30631 )
+which has been integrated into FreeBSD 4.6.
+
+=head2 $^X doesn't always contain a full path in FreeBSD
+
+perl 5.8.0 sets C<$^X> where possible to a full path by asking the operating
+system. On FreeBSD the full path of the perl interpreter is found by reading
+the symlink F</proc/curproc/file>. There is a bug on FreeBSD, where the
+result of reading this symlink is can be wrong in certain circumstances
+(see http://www.freebsd.org/cgi/query-pr.cgi?pr=35703 ).
+In these cases perl will fall back to the old behaviour of using C's
+argv[0] value for C<$^X>.
+
+=head2 Perl will no longer be part of "base FreeBSD"
+
+Not as bad as it sounds--what this means is that Perl will no longer be
+part of the B<kernel build system> of FreeBSD. Perl will still very
+probably be part of the "default install", and in any case the latest
+version will be in the ports system. The first FreeBSD version this
+change will affect is 5.0, all 4.n versions will keep the status quo.
+
+=head1 AUTHOR
+
+Nicholas Clark <nick@ccl4.org>, collating wisdom supplied by Slaven Rezic
+and Tim Bunce.
+
+Please report any errors, updates, or suggestions to F<perlbug@perl.org>.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlfunc.pod b/Master/tlpkg/tlperl/lib/pods/perlfunc.pod
new file mode 100644
index 00000000000..6b454cc9a59
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlfunc.pod
@@ -0,0 +1,7737 @@
+=head1 NAME
+X<function>
+
+perlfunc - Perl builtin functions
+
+=head1 DESCRIPTION
+
+The functions in this section can serve as terms in an expression.
+They fall into two major categories: list operators and named unary
+operators. These differ in their precedence relationship with a
+following comma. (See the precedence table in L<perlop>.) List
+operators take more than one argument, while unary operators can never
+take more than one argument. Thus, a comma terminates the argument of
+a unary operator, but merely separates the arguments of a list
+operator. A unary operator generally provides a scalar context to its
+argument, while a list operator may provide either scalar or list
+contexts for its arguments. If it does both, scalar arguments
+come first and list argument follow, and there can only ever
+be one such list argument. For instance, splice() has three scalar
+arguments followed by a list, whereas gethostbyname() has four scalar
+arguments.
+
+In the syntax descriptions that follow, list operators that expect a
+list (and provide list context for elements of the list) are shown
+with LIST as an argument. Such a list may consist of any combination
+of scalar arguments or list values; the list values will be included
+in the list as if each individual element were interpolated at that
+point in the list, forming a longer single-dimensional list value.
+Commas should separate literal elements of the LIST.
+
+Any function in the list below may be used either with or without
+parentheses around its arguments. (The syntax descriptions omit the
+parentheses.) If you use parentheses, the simple but occasionally
+surprising rule is this: It I<looks> like a function, therefore it I<is> a
+function, and precedence doesn't matter. Otherwise it's a list
+operator or unary operator, and precedence does matter. Whitespace
+between the function and left parenthesis doesn't count, so sometimes
+you need to be careful:
+
+ print 1+2+4; # Prints 7.
+ print(1+2) + 4; # Prints 3.
+ print (1+2)+4; # Also prints 3!
+ print +(1+2)+4; # Prints 7.
+ print ((1+2)+4); # Prints 7.
+
+If you run Perl with the B<-w> switch it can warn you about this. For
+example, the third line above produces:
+
+ print (...) interpreted as function at - line 1.
+ Useless use of integer addition in void context at - line 1.
+
+A few functions take no arguments at all, and therefore work as neither
+unary nor list operators. These include such functions as C<time>
+and C<endpwent>. For example, C<time+86_400> always means
+C<time() + 86_400>.
+
+For functions that can be used in either a scalar or list context,
+nonabortive failure is generally indicated in a scalar context by
+returning the undefined value, and in a list context by returning the
+empty list.
+
+Remember the following important rule: There is B<no rule> that relates
+the behavior of an expression in list context to its behavior in scalar
+context, or vice versa. It might do two totally different things.
+Each operator and function decides which sort of value would be most
+appropriate to return in scalar context. Some operators return the
+length of the list that would have been returned in list context. Some
+operators return the first value in the list. Some operators return the
+last value in the list. Some operators return a count of successful
+operations. In general, they do what you want, unless you want
+consistency.
+X<context>
+
+A named array in scalar context is quite different from what would at
+first glance appear to be a list in scalar context. You can't get a list
+like C<(1,2,3)> into being in scalar context, because the compiler knows
+the context at compile time. It would generate the scalar comma operator
+there, not the list construction version of the comma. That means it
+was never a list to start with.
+
+In general, functions in Perl that serve as wrappers for system calls ("syscalls")
+of the same name (like chown(2), fork(2), closedir(2), etc.) all return
+true when they succeed and C<undef> otherwise, as is usually mentioned
+in the descriptions below. This is different from the C interfaces,
+which return C<-1> on failure. Exceptions to this rule are C<wait>,
+C<waitpid>, and C<syscall>. System calls also set the special C<$!>
+variable on failure. Other functions do not, except accidentally.
+
+Extension modules can also hook into the Perl parser to define new
+kinds of keyword-headed expression. These may look like functions, but
+may also look completely different. The syntax following the keyword
+is defined entirely by the extension. If you are an implementor, see
+L<perlapi/PL_keyword_plugin> for the mechanism. If you are using such
+a module, see the module's documentation for details of the syntax that
+it defines.
+
+=head2 Perl Functions by Category
+X<function>
+
+Here are Perl's functions (including things that look like
+functions, like some keywords and named operators)
+arranged by category. Some functions appear in more
+than one place.
+
+=over 4
+
+=item Functions for SCALARs or strings
+X<scalar> X<string> X<character>
+
+C<chomp>, C<chop>, C<chr>, C<crypt>, C<hex>, C<index>, C<lc>, C<lcfirst>,
+C<length>, C<oct>, C<ord>, C<pack>, C<q//>, C<qq//>, C<reverse>,
+C<rindex>, C<sprintf>, C<substr>, C<tr///>, C<uc>, C<ucfirst>, C<y///>
+
+=item Regular expressions and pattern matching
+X<regular expression> X<regex> X<regexp>
+
+C<m//>, C<pos>, C<quotemeta>, C<s///>, C<split>, C<study>, C<qr//>
+
+=item Numeric functions
+X<numeric> X<number> X<trigonometric> X<trigonometry>
+
+C<abs>, C<atan2>, C<cos>, C<exp>, C<hex>, C<int>, C<log>, C<oct>, C<rand>,
+C<sin>, C<sqrt>, C<srand>
+
+=item Functions for real @ARRAYs
+X<array>
+
+C<pop>, C<push>, C<shift>, C<splice>, C<unshift>
+
+=item Functions for list data
+X<list>
+
+C<grep>, C<join>, C<map>, C<qw//>, C<reverse>, C<sort>, C<unpack>
+
+=item Functions for real %HASHes
+X<hash>
+
+C<delete>, C<each>, C<exists>, C<keys>, C<values>
+
+=item Input and output functions
+X<I/O> X<input> X<output> X<dbm>
+
+C<binmode>, C<close>, C<closedir>, C<dbmclose>, C<dbmopen>, C<die>, C<eof>,
+C<fileno>, C<flock>, C<format>, C<getc>, C<print>, C<printf>, C<read>,
+C<readdir>, C<rewinddir>, C<say>, C<seek>, C<seekdir>, C<select>, C<syscall>,
+C<sysread>, C<sysseek>, C<syswrite>, C<tell>, C<telldir>, C<truncate>,
+C<warn>, C<write>
+
+=item Functions for fixed length data or records
+
+C<pack>, C<read>, C<syscall>, C<sysread>, C<syswrite>, C<unpack>, C<vec>
+
+=item Functions for filehandles, files, or directories
+X<file> X<filehandle> X<directory> X<pipe> X<link> X<symlink>
+
+C<-I<X>>, C<chdir>, C<chmod>, C<chown>, C<chroot>, C<fcntl>, C<glob>,
+C<ioctl>, C<link>, C<lstat>, C<mkdir>, C<open>, C<opendir>,
+C<readlink>, C<rename>, C<rmdir>, C<stat>, C<symlink>, C<sysopen>,
+C<umask>, C<unlink>, C<utime>
+
+=item Keywords related to the control flow of your Perl program
+X<control flow>
+
+C<caller>, C<continue>, C<die>, C<do>, C<dump>, C<eval>, C<exit>,
+C<goto>, C<last>, C<next>, C<redo>, C<return>, C<sub>, C<wantarray>
+
+=item Keywords related to switch
+
+C<break>, C<continue>, C<given>, C<when>, C<default>
+
+(These are available only if you enable the C<"switch"> feature.
+See L<feature> and L<perlsyn/"Switch statements">.)
+
+=item Keywords related to scoping
+
+C<caller>, C<import>, C<local>, C<my>, C<our>, C<state>, C<package>,
+C<use>
+
+(C<state> is available only if the C<"state"> feature is enabled. See
+L<feature>.)
+
+=item Miscellaneous functions
+
+C<defined>, C<dump>, C<eval>, C<formline>, C<local>, C<my>, C<our>,
+C<reset>, C<scalar>, C<state>, C<undef>, C<wantarray>
+
+=item Functions for processes and process groups
+X<process> X<pid> X<process id>
+
+C<alarm>, C<exec>, C<fork>, C<getpgrp>, C<getppid>, C<getpriority>, C<kill>,
+C<pipe>, C<qx//>, C<setpgrp>, C<setpriority>, C<sleep>, C<system>,
+C<times>, C<wait>, C<waitpid>
+
+=item Keywords related to Perl modules
+X<module>
+
+C<do>, C<import>, C<no>, C<package>, C<require>, C<use>
+
+=item Keywords related to classes and object-orientation
+X<object> X<class> X<package>
+
+C<bless>, C<dbmclose>, C<dbmopen>, C<package>, C<ref>, C<tie>, C<tied>,
+C<untie>, C<use>
+
+=item Low-level socket functions
+X<socket> X<sock>
+
+C<accept>, C<bind>, C<connect>, C<getpeername>, C<getsockname>,
+C<getsockopt>, C<listen>, C<recv>, C<send>, C<setsockopt>, C<shutdown>,
+C<socket>, C<socketpair>
+
+=item System V interprocess communication functions
+X<IPC> X<System V> X<semaphore> X<shared memory> X<memory> X<message>
+
+C<msgctl>, C<msgget>, C<msgrcv>, C<msgsnd>, C<semctl>, C<semget>, C<semop>,
+C<shmctl>, C<shmget>, C<shmread>, C<shmwrite>
+
+=item Fetching user and group info
+X<user> X<group> X<password> X<uid> X<gid> X<passwd> X</etc/passwd>
+
+C<endgrent>, C<endhostent>, C<endnetent>, C<endpwent>, C<getgrent>,
+C<getgrgid>, C<getgrnam>, C<getlogin>, C<getpwent>, C<getpwnam>,
+C<getpwuid>, C<setgrent>, C<setpwent>
+
+=item Fetching network info
+X<network> X<protocol> X<host> X<hostname> X<IP> X<address> X<service>
+
+C<endprotoent>, C<endservent>, C<gethostbyaddr>, C<gethostbyname>,
+C<gethostent>, C<getnetbyaddr>, C<getnetbyname>, C<getnetent>,
+C<getprotobyname>, C<getprotobynumber>, C<getprotoent>,
+C<getservbyname>, C<getservbyport>, C<getservent>, C<sethostent>,
+C<setnetent>, C<setprotoent>, C<setservent>
+
+=item Time-related functions
+X<time> X<date>
+
+C<gmtime>, C<localtime>, C<time>, C<times>
+
+=item Functions new in perl5
+X<perl5>
+
+C<abs>, C<bless>, C<break>, C<chomp>, C<chr>, C<continue>, C<default>,
+C<exists>, C<formline>, C<given>, C<glob>, C<import>, C<lc>, C<lcfirst>,
+C<lock>, C<map>, C<my>, C<no>, C<our>, C<prototype>, C<qr//>, C<qw//>, C<qx//>,
+C<readline>, C<readpipe>, C<ref>, C<sub>*, C<sysopen>, C<tie>, C<tied>, C<uc>,
+C<ucfirst>, C<untie>, C<use>, C<when>
+
+* C<sub> was a keyword in Perl 4, but in Perl 5 it is an
+operator, which can be used in expressions.
+
+=item Functions obsoleted in perl5
+
+C<dbmclose>, C<dbmopen>
+
+=back
+
+=head2 Portability
+X<portability> X<Unix> X<portable>
+
+Perl was born in Unix and can therefore access all common Unix
+system calls. In non-Unix environments, the functionality of some
+Unix system calls may not be available, or details of the available
+functionality may differ slightly. The Perl functions affected
+by this are:
+
+C<-X>, C<binmode>, C<chmod>, C<chown>, C<chroot>, C<crypt>,
+C<dbmclose>, C<dbmopen>, C<dump>, C<endgrent>, C<endhostent>,
+C<endnetent>, C<endprotoent>, C<endpwent>, C<endservent>, C<exec>,
+C<fcntl>, C<flock>, C<fork>, C<getgrent>, C<getgrgid>, C<gethostbyname>,
+C<gethostent>, C<getlogin>, C<getnetbyaddr>, C<getnetbyname>, C<getnetent>,
+C<getppid>, C<getpgrp>, C<getpriority>, C<getprotobynumber>,
+C<getprotoent>, C<getpwent>, C<getpwnam>, C<getpwuid>,
+C<getservbyport>, C<getservent>, C<getsockopt>, C<glob>, C<ioctl>,
+C<kill>, C<link>, C<lstat>, C<msgctl>, C<msgget>, C<msgrcv>,
+C<msgsnd>, C<open>, C<pipe>, C<readlink>, C<rename>, C<select>, C<semctl>,
+C<semget>, C<semop>, C<setgrent>, C<sethostent>, C<setnetent>,
+C<setpgrp>, C<setpriority>, C<setprotoent>, C<setpwent>,
+C<setservent>, C<setsockopt>, C<shmctl>, C<shmget>, C<shmread>,
+C<shmwrite>, C<socket>, C<socketpair>,
+C<stat>, C<symlink>, C<syscall>, C<sysopen>, C<system>,
+C<times>, C<truncate>, C<umask>, C<unlink>,
+C<utime>, C<wait>, C<waitpid>
+
+For more information about the portability of these functions, see
+L<perlport> and other available platform-specific documentation.
+
+=head2 Alphabetical Listing of Perl Functions
+
+=over
+
+=item -X FILEHANDLE
+X<-r>X<-w>X<-x>X<-o>X<-R>X<-W>X<-X>X<-O>X<-e>X<-z>X<-s>X<-f>X<-d>X<-l>X<-p>
+X<-S>X<-b>X<-c>X<-t>X<-u>X<-g>X<-k>X<-T>X<-B>X<-M>X<-A>X<-C>
+
+=item -X EXPR
+
+=item -X DIRHANDLE
+
+=item -X
+
+A file test, where X is one of the letters listed below. This unary
+operator takes one argument, either a filename, a filehandle, or a dirhandle,
+and tests the associated file to see if something is true about it. If the
+argument is omitted, tests C<$_>, except for C<-t>, which tests STDIN.
+Unless otherwise documented, it returns C<1> for true and C<''> for false, or
+the undefined value if the file doesn't exist. Despite the funny
+names, precedence is the same as any other named unary operator. The
+operator may be any of:
+
+ -r File is readable by effective uid/gid.
+ -w File is writable by effective uid/gid.
+ -x File is executable by effective uid/gid.
+ -o File is owned by effective uid.
+
+ -R File is readable by real uid/gid.
+ -W File is writable by real uid/gid.
+ -X File is executable by real uid/gid.
+ -O File is owned by real uid.
+
+ -e File exists.
+ -z File has zero size (is empty).
+ -s File has nonzero size (returns size in bytes).
+
+ -f File is a plain file.
+ -d File is a directory.
+ -l File is a symbolic link.
+ -p File is a named pipe (FIFO), or Filehandle is a pipe.
+ -S File is a socket.
+ -b File is a block special file.
+ -c File is a character special file.
+ -t Filehandle is opened to a tty.
+
+ -u File has setuid bit set.
+ -g File has setgid bit set.
+ -k File has sticky bit set.
+
+ -T File is an ASCII text file (heuristic guess).
+ -B File is a "binary" file (opposite of -T).
+
+ -M Script start time minus file modification time, in days.
+ -A Same for access time.
+ -C Same for inode change time (Unix, may differ for other platforms)
+
+Example:
+
+ while (<>) {
+ chomp;
+ next unless -f $_; # ignore specials
+ #...
+ }
+
+The interpretation of the file permission operators C<-r>, C<-R>,
+C<-w>, C<-W>, C<-x>, and C<-X> is by default based solely on the mode
+of the file and the uids and gids of the user. There may be other
+reasons you can't actually read, write, or execute the file: for
+example network filesystem access controls, ACLs (access control lists),
+read-only filesystems, and unrecognized executable formats. Note
+that the use of these six specific operators to verify if some operation
+is possible is usually a mistake, because it may be open to race
+conditions.
+
+Also note that, for the superuser on the local filesystems, the C<-r>,
+C<-R>, C<-w>, and C<-W> tests always return 1, and C<-x> and C<-X> return 1
+if any execute bit is set in the mode. Scripts run by the superuser
+may thus need to do a stat() to determine the actual mode of the file,
+or temporarily set their effective uid to something else.
+
+If you are using ACLs, there is a pragma called C<filetest> that may
+produce more accurate results than the bare stat() mode bits.
+When under the C<use filetest 'access'> the above-mentioned filetests
+test whether the permission can (not) be granted using the
+access(2) family of system calls. Also note that the C<-x> and C<-X> may
+under this pragma return true even if there are no execute permission
+bits set (nor any extra execute permission ACLs). This strangeness is
+due to the underlying system calls' definitions. Note also that, due to
+the implementation of C<use filetest 'access'>, the C<_> special
+filehandle won't cache the results of the file tests when this pragma is
+in effect. Read the documentation for the C<filetest> pragma for more
+information.
+
+Note that C<-s/a/b/> does not do a negated substitution. Saying
+C<-exp($foo)> still works as expected, however: only single letters
+following a minus are interpreted as file tests.
+
+The C<-T> and C<-B> switches work as follows. The first block or so of the
+file is examined for odd characters such as strange control codes or
+characters with the high bit set. If too many strange characters (>30%)
+are found, it's a C<-B> file; otherwise it's a C<-T> file. Also, any file
+containing a zero byte in the first block is considered a binary file. If C<-T>
+or C<-B> is used on a filehandle, the current IO buffer is examined
+rather than the first block. Both C<-T> and C<-B> return true on an empty
+file, or a file at EOF when testing a filehandle. Because you have to
+read a file to do the C<-T> test, on most occasions you want to use a C<-f>
+against the file first, as in C<next unless -f $file && -T $file>.
+
+If any of the file tests (or either the C<stat> or C<lstat> operators) are given
+the special filehandle consisting of a solitary underline, then the stat
+structure of the previous file test (or stat operator) is used, saving
+a system call. (This doesn't work with C<-t>, and you need to remember
+that lstat() and C<-l> leave values in the stat structure for the
+symbolic link, not the real file.) (Also, if the stat buffer was filled by
+an C<lstat> call, C<-T> and C<-B> will reset it with the results of C<stat _>).
+Example:
+
+ print "Can do.\n" if -r $a || -w _ || -x _;
+
+ stat($filename);
+ print "Readable\n" if -r _;
+ print "Writable\n" if -w _;
+ print "Executable\n" if -x _;
+ print "Setuid\n" if -u _;
+ print "Setgid\n" if -g _;
+ print "Sticky\n" if -k _;
+ print "Text\n" if -T _;
+ print "Binary\n" if -B _;
+
+As of Perl 5.9.1, as a form of purely syntactic sugar, you can stack file
+test operators, in a way that C<-f -w -x $file> is equivalent to
+C<-x $file && -w _ && -f _>. (This is only fancy fancy: if you use
+the return value of C<-f $file> as an argument to another filetest
+operator, no special magic will happen.)
+
+=item abs VALUE
+X<abs> X<absolute>
+
+=item abs
+
+Returns the absolute value of its argument.
+If VALUE is omitted, uses C<$_>.
+
+=item accept NEWSOCKET,GENERICSOCKET
+X<accept>
+
+Accepts an incoming socket connect, just as accept(2)
+does. Returns the packed address if it succeeded, false otherwise.
+See the example in L<perlipc/"Sockets: Client/Server Communication">.
+
+On systems that support a close-on-exec flag on files, the flag will
+be set for the newly opened file descriptor, as determined by the
+value of $^F. See L<perlvar/$^F>.
+
+=item alarm SECONDS
+X<alarm>
+X<SIGALRM>
+X<timer>
+
+=item alarm
+
+Arranges to have a SIGALRM delivered to this process after the
+specified number of wallclock seconds has elapsed. If SECONDS is not
+specified, the value stored in C<$_> is used. (On some machines,
+unfortunately, the elapsed time may be up to one second less or more
+than you specified because of how seconds are counted, and process
+scheduling may delay the delivery of the signal even further.)
+
+Only one timer may be counting at once. Each call disables the
+previous timer, and an argument of C<0> may be supplied to cancel the
+previous timer without starting a new one. The returned value is the
+amount of time remaining on the previous timer.
+
+For delays of finer granularity than one second, the Time::HiRes module
+(from CPAN, and starting from Perl 5.8 part of the standard
+distribution) provides ualarm(). You may also use Perl's four-argument
+version of select() leaving the first three arguments undefined, or you
+might be able to use the C<syscall> interface to access setitimer(2) if
+your system supports it. See L<perlfaq8> for details.
+
+It is usually a mistake to intermix C<alarm> and C<sleep> calls, because
+C<sleep> may be internally implemented on your system with C<alarm>.
+
+If you want to use C<alarm> to time out a system call you need to use an
+C<eval>/C<die> pair. You can't rely on the alarm causing the system call to
+fail with C<$!> set to C<EINTR> because Perl sets up signal handlers to
+restart system calls on some systems. Using C<eval>/C<die> always works,
+modulo the caveats given in L<perlipc/"Signals">.
+
+ eval {
+ local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
+ alarm $timeout;
+ $nread = sysread SOCKET, $buffer, $size;
+ alarm 0;
+ };
+ if ($@) {
+ die unless $@ eq "alarm\n"; # propagate unexpected errors
+ # timed out
+ }
+ else {
+ # didn't
+ }
+
+For more information see L<perlipc>.
+
+=item atan2 Y,X
+X<atan2> X<arctangent> X<tan> X<tangent>
+
+Returns the arctangent of Y/X in the range -PI to PI.
+
+For the tangent operation, you may use the C<Math::Trig::tan>
+function, or use the familiar relation:
+
+ sub tan { sin($_[0]) / cos($_[0]) }
+
+The return value for C<atan2(0,0)> is implementation-defined; consult
+your atan2(3) manpage for more information.
+
+=item bind SOCKET,NAME
+X<bind>
+
+Binds a network address to a socket, just as bind(2)
+does. Returns true if it succeeded, false otherwise. NAME should be a
+packed address of the appropriate type for the socket. See the examples in
+L<perlipc/"Sockets: Client/Server Communication">.
+
+=item binmode FILEHANDLE, LAYER
+X<binmode> X<binary> X<text> X<DOS> X<Windows>
+
+=item binmode FILEHANDLE
+
+Arranges for FILEHANDLE to be read or written in "binary" or "text"
+mode on systems where the run-time libraries distinguish between
+binary and text files. If FILEHANDLE is an expression, the value is
+taken as the name of the filehandle. Returns true on success,
+otherwise it returns C<undef> and sets C<$!> (errno).
+
+On some systems (in general, DOS and Windows-based systems) binmode()
+is necessary when you're not working with a text file. For the sake
+of portability it is a good idea to always use it when appropriate,
+and to never use it when it isn't appropriate. Also, people can
+set their I/O to be by default UTF-8 encoded Unicode, not bytes.
+
+In other words: regardless of platform, use binmode() on binary data,
+like for example images.
+
+If LAYER is present it is a single string, but may contain multiple
+directives. The directives alter the behaviour of the filehandle.
+When LAYER is present using binmode on a text file makes sense.
+
+If LAYER is omitted or specified as C<:raw> the filehandle is made
+suitable for passing binary data. This includes turning off possible CRLF
+translation and marking it as bytes (as opposed to Unicode characters).
+Note that, despite what may be implied in I<"Programming Perl"> (the
+Camel, 3rd edition) or elsewhere, C<:raw> is I<not> simply the inverse of C<:crlf>.
+Other layers that would affect the binary nature of the stream are
+I<also> disabled. See L<PerlIO>, L<perlrun>, and the discussion about the
+PERLIO environment variable.
+
+The C<:bytes>, C<:crlf>, C<:utf8>, and any other directives of the
+form C<:...>, are called I/O I<layers>. The C<open> pragma can be used to
+establish default I/O layers. See L<open>.
+
+I<The LAYER parameter of the binmode() function is described as "DISCIPLINE"
+in "Programming Perl, 3rd Edition". However, since the publishing of this
+book, by many known as "Camel III", the consensus of the naming of this
+functionality has moved from "discipline" to "layer". All documentation
+of this version of Perl therefore refers to "layers" rather than to
+"disciplines". Now back to the regularly scheduled documentation...>
+
+To mark FILEHANDLE as UTF-8, use C<:utf8> or C<:encoding(utf8)>.
+C<:utf8> just marks the data as UTF-8 without further checking,
+while C<:encoding(utf8)> checks the data for actually being valid
+UTF-8. More details can be found in L<PerlIO::encoding>.
+
+In general, binmode() should be called after open() but before any I/O
+is done on the filehandle. Calling binmode() normally flushes any
+pending buffered output data (and perhaps pending input data) on the
+handle. An exception to this is the C<:encoding> layer that
+changes the default character encoding of the handle, see L<open>.
+The C<:encoding> layer sometimes needs to be called in
+mid-stream, and it doesn't flush the stream. The C<:encoding>
+also implicitly pushes on top of itself the C<:utf8> layer because
+internally Perl operates on UTF8-encoded Unicode characters.
+
+The operating system, device drivers, C libraries, and Perl run-time
+system all work together to let the programmer treat a single
+character (C<\n>) as the line terminator, irrespective of the external
+representation. On many operating systems, the native text file
+representation matches the internal representation, but on some
+platforms the external representation of C<\n> is made up of more than
+one character.
+
+Mac OS, all variants of Unix, and Stream_LF files on VMS use a single
+character to end each line in the external representation of text (even
+though that single character is CARRIAGE RETURN on Mac OS and LINE FEED
+on Unix and most VMS files). In other systems like OS/2, DOS and the
+various flavors of MS-Windows your program sees a C<\n> as a simple C<\cJ>,
+but what's stored in text files are the two characters C<\cM\cJ>. That
+means that, if you don't use binmode() on these systems, C<\cM\cJ>
+sequences on disk will be converted to C<\n> on input, and any C<\n> in
+your program will be converted back to C<\cM\cJ> on output. This is what
+you want for text files, but it can be disastrous for binary files.
+
+Another consequence of using binmode() (on some systems) is that
+special end-of-file markers will be seen as part of the data stream.
+For systems from the Microsoft family this means that if your binary
+data contains C<\cZ>, the I/O subsystem will regard it as the end of
+the file, unless you use binmode().
+
+binmode() is important not only for readline() and print() operations,
+but also when using read(), seek(), sysread(), syswrite() and tell()
+(see L<perlport> for more details). See the C<$/> and C<$\> variables
+in L<perlvar> for how to manually set your input and output
+line-termination sequences.
+
+=item bless REF,CLASSNAME
+X<bless>
+
+=item bless REF
+
+This function tells the thingy referenced by REF that it is now an object
+in the CLASSNAME package. If CLASSNAME is omitted, the current package
+is used. Because a C<bless> is often the last thing in a constructor,
+it returns the reference for convenience. Always use the two-argument
+version if a derived class might inherit the function doing the blessing.
+See L<perltoot> and L<perlobj> for more about the blessing (and blessings)
+of objects.
+
+Consider always blessing objects in CLASSNAMEs that are mixed case.
+Namespaces with all lowercase names are considered reserved for
+Perl pragmata. Builtin types have all uppercase names. To prevent
+confusion, you may wish to avoid such package names as well. Make sure
+that CLASSNAME is a true value.
+
+See L<perlmod/"Perl Modules">.
+
+=item break
+
+Break out of a C<given()> block.
+
+This keyword is enabled by the C<"switch"> feature: see L<feature>
+for more information.
+
+=item caller EXPR
+X<caller> X<call stack> X<stack> X<stack trace>
+
+=item caller
+
+Returns the context of the current subroutine call. In scalar context,
+returns the caller's package name if there I<is> a caller (that is, if
+we're in a subroutine or C<eval> or C<require>) and the undefined value
+otherwise. In list context, returns
+
+ # 0 1 2
+ ($package, $filename, $line) = caller;
+
+With EXPR, it returns some extra information that the debugger uses to
+print a stack trace. The value of EXPR indicates how many call frames
+to go back before the current one.
+
+ # 0 1 2 3 4
+ ($package, $filename, $line, $subroutine, $hasargs,
+
+ # 5 6 7 8 9 10
+ $wantarray, $evaltext, $is_require, $hints, $bitmask, $hinthash)
+ = caller($i);
+
+Here $subroutine may be C<(eval)> if the frame is not a subroutine
+call, but an C<eval>. In such a case additional elements $evaltext and
+C<$is_require> are set: C<$is_require> is true if the frame is created by a
+C<require> or C<use> statement, $evaltext contains the text of the
+C<eval EXPR> statement. In particular, for an C<eval BLOCK> statement,
+$subroutine is C<(eval)>, but $evaltext is undefined. (Note also that
+each C<use> statement creates a C<require> frame inside an C<eval EXPR>
+frame.) $subroutine may also be C<(unknown)> if this particular
+subroutine happens to have been deleted from the symbol table.
+C<$hasargs> is true if a new instance of C<@_> was set up for the frame.
+C<$hints> and C<$bitmask> contain pragmatic hints that the caller was
+compiled with. The C<$hints> and C<$bitmask> values are subject to change
+between versions of Perl, and are not meant for external use.
+
+C<$hinthash> is a reference to a hash containing the value of C<%^H> when the
+caller was compiled, or C<undef> if C<%^H> was empty. Do not modify the values
+of this hash, as they are the actual values stored in the optree.
+
+Furthermore, when called from within the DB package, caller returns more
+detailed information: it sets the list variable C<@DB::args> to be the
+arguments with which the subroutine was invoked.
+
+Be aware that the optimizer might have optimized call frames away before
+C<caller> had a chance to get the information. That means that C<caller(N)>
+might not return information about the call frame you expect it to, for
+C<< N > 1 >>. In particular, C<@DB::args> might have information from the
+previous time C<caller> was called.
+
+Also be aware that setting C<@DB::args> is I<best effort>, intended for
+debugging or generating backtraces, and should not be relied upon. In
+particular, as C<@_> contains aliases to the caller's arguments, Perl does
+not take a copy of C<@_>, so C<@DB::args> will contain modifications the
+subroutine makes to C<@_> or its contents, not the original values at call
+time. C<@DB::args>, like C<@_>, does not hold explicit references to its
+elements, so under certain cases its elements may have become freed and
+reallocated for other variables or temporary values. Finally, a side effect
+of the current implementation means that the effects of C<shift @_> can
+I<normally> be undone (but not C<pop @_> or other splicing, and not if a
+reference to C<@_> has been taken, and subject to the caveat about reallocated
+elements), so C<@DB::args> is actually a hybrid of the current state and
+initial state of C<@_>. Buyer beware.
+
+=item chdir EXPR
+X<chdir>
+X<cd>
+X<directory, change>
+
+=item chdir FILEHANDLE
+
+=item chdir DIRHANDLE
+
+=item chdir
+
+Changes the working directory to EXPR, if possible. If EXPR is omitted,
+changes to the directory specified by C<$ENV{HOME}>, if set; if not,
+changes to the directory specified by C<$ENV{LOGDIR}>. (Under VMS, the
+variable C<$ENV{SYS$LOGIN}> is also checked, and used if it is set.) If
+neither is set, C<chdir> does nothing. It returns true on success,
+false otherwise. See the example under C<die>.
+
+On systems that support fchdir(2), you may pass a filehandle or
+directory handle as argument. On systems that don't support fchdir(2),
+passing handles raises an exception.
+
+=item chmod LIST
+X<chmod> X<permission> X<mode>
+
+Changes the permissions of a list of files. The first element of the
+list must be the numerical mode, which should probably be an octal
+number, and which definitely should I<not> be a string of octal digits:
+C<0644> is okay, but C<"0644"> is not. Returns the number of files
+successfully changed. See also L</oct>, if all you have is a string.
+
+ $cnt = chmod 0755, "foo", "bar";
+ chmod 0755, @executables;
+ $mode = "0644"; chmod $mode, "foo"; # !!! sets mode to
+ # --w----r-T
+ $mode = "0644"; chmod oct($mode), "foo"; # this is better
+ $mode = 0644; chmod $mode, "foo"; # this is best
+
+On systems that support fchmod(2), you may pass filehandles among the
+files. On systems that don't support fchmod(2), passing filehandles raises
+an exception. Filehandles must be passed as globs or glob references to be
+recognized; barewords are considered filenames.
+
+ open(my $fh, "<", "foo");
+ my $perm = (stat $fh)[2] & 07777;
+ chmod($perm | 0600, $fh);
+
+You can also import the symbolic C<S_I*> constants from the C<Fcntl>
+module:
+
+ use Fcntl qw( :mode );
+ chmod S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH, @executables;
+ # Identical to the chmod 0755 of the example above.
+
+=item chomp VARIABLE
+X<chomp> X<INPUT_RECORD_SEPARATOR> X<$/> X<newline> X<eol>
+
+=item chomp( LIST )
+
+=item chomp
+
+This safer version of L</chop> removes any trailing string
+that corresponds to the current value of C<$/> (also known as
+$INPUT_RECORD_SEPARATOR in the C<English> module). It returns the total
+number of characters removed from all its arguments. It's often used to
+remove the newline from the end of an input record when you're worried
+that the final record may be missing its newline. When in paragraph
+mode (C<$/ = "">), it removes all trailing newlines from the string.
+When in slurp mode (C<$/ = undef>) or fixed-length record mode (C<$/> is
+a reference to an integer or the like, see L<perlvar>) chomp() won't
+remove anything.
+If VARIABLE is omitted, it chomps C<$_>. Example:
+
+ while (<>) {
+ chomp; # avoid \n on last field
+ @array = split(/:/);
+ # ...
+ }
+
+If VARIABLE is a hash, it chomps the hash's values, but not its keys.
+
+You can actually chomp anything that's an lvalue, including an assignment:
+
+ chomp($cwd = `pwd`);
+ chomp($answer = <STDIN>);
+
+If you chomp a list, each element is chomped, and the total number of
+characters removed is returned.
+
+Note that parentheses are necessary when you're chomping anything
+that is not a simple variable. This is because C<chomp $cwd = `pwd`;>
+is interpreted as C<(chomp $cwd) = `pwd`;>, rather than as
+C<chomp( $cwd = `pwd` )> which you might expect. Similarly,
+C<chomp $a, $b> is interpreted as C<chomp($a), $b> rather than
+as C<chomp($a, $b)>.
+
+=item chop VARIABLE
+X<chop>
+
+=item chop( LIST )
+
+=item chop
+
+Chops off the last character of a string and returns the character
+chopped. It is much more efficient than C<s/.$//s> because it neither
+scans nor copies the string. If VARIABLE is omitted, chops C<$_>.
+If VARIABLE is a hash, it chops the hash's values, but not its keys.
+
+You can actually chop anything that's an lvalue, including an assignment.
+
+If you chop a list, each element is chopped. Only the value of the
+last C<chop> is returned.
+
+Note that C<chop> returns the last character. To return all but the last
+character, use C<substr($string, 0, -1)>.
+
+See also L</chomp>.
+
+=item chown LIST
+X<chown> X<owner> X<user> X<group>
+
+Changes the owner (and group) of a list of files. The first two
+elements of the list must be the I<numeric> uid and gid, in that
+order. A value of -1 in either position is interpreted by most
+systems to leave that value unchanged. Returns the number of files
+successfully changed.
+
+ $cnt = chown $uid, $gid, 'foo', 'bar';
+ chown $uid, $gid, @filenames;
+
+On systems that support fchown(2), you may pass filehandles among the
+files. On systems that don't support fchown(2), passing filehandles raises
+an exception. Filehandles must be passed as globs or glob references to be
+recognized; barewords are considered filenames.
+
+Here's an example that looks up nonnumeric uids in the passwd file:
+
+ print "User: ";
+ chomp($user = <STDIN>);
+ print "Files: ";
+ chomp($pattern = <STDIN>);
+
+ ($login,$pass,$uid,$gid) = getpwnam($user)
+ or die "$user not in passwd file";
+
+ @ary = glob($pattern); # expand filenames
+ chown $uid, $gid, @ary;
+
+On most systems, you are not allowed to change the ownership of the
+file unless you're the superuser, although you should be able to change
+the group to any of your secondary groups. On insecure systems, these
+restrictions may be relaxed, but this is not a portable assumption.
+On POSIX systems, you can detect this condition this way:
+
+ use POSIX qw(sysconf _PC_CHOWN_RESTRICTED);
+ $can_chown_giveaway = not sysconf(_PC_CHOWN_RESTRICTED);
+
+=item chr NUMBER
+X<chr> X<character> X<ASCII> X<Unicode>
+
+=item chr
+
+Returns the character represented by that NUMBER in the character set.
+For example, C<chr(65)> is C<"A"> in either ASCII or Unicode, and
+chr(0x263a) is a Unicode smiley face.
+
+Negative values give the Unicode replacement character (chr(0xfffd)),
+except under the L<bytes> pragma, where the low eight bits of the value
+(truncated to an integer) are used.
+
+If NUMBER is omitted, uses C<$_>.
+
+For the reverse, use L</ord>.
+
+Note that characters from 128 to 255 (inclusive) are by default
+internally not encoded as UTF-8 for backward compatibility reasons.
+
+See L<perlunicode> for more about Unicode.
+
+=item chroot FILENAME
+X<chroot> X<root>
+
+=item chroot
+
+This function works like the system call by the same name: it makes the
+named directory the new root directory for all further pathnames that
+begin with a C</> by your process and all its children. (It doesn't
+change your current working directory, which is unaffected.) For security
+reasons, this call is restricted to the superuser. If FILENAME is
+omitted, does a C<chroot> to C<$_>.
+
+=item close FILEHANDLE
+X<close>
+
+=item close
+
+Closes the file or pipe associated with the filehandle, flushes the IO
+buffers, and closes the system file descriptor. Returns true if those
+operations have succeeded and if no error was reported by any PerlIO
+layer. Closes the currently selected filehandle if the argument is
+omitted.
+
+You don't have to close FILEHANDLE if you are immediately going to do
+another C<open> on it, because C<open> closes it for you. (See
+C<open>.) However, an explicit C<close> on an input file resets the line
+counter (C<$.>), while the implicit close done by C<open> does not.
+
+If the filehandle came from a piped open, C<close> returns false if one of
+the other syscalls involved fails or if its program exits with non-zero
+status. If the only problem was that the program exited non-zero, C<$!>
+will be set to C<0>. Closing a pipe also waits for the process executing
+on the pipe to exit--in case you wish to look at the output of the pipe
+afterwards--and implicitly puts the exit status value of that command into
+C<$?> and C<${^CHILD_ERROR_NATIVE}>.
+
+Closing the read end of a pipe before the process writing to it at the
+other end is done writing results in the writer receiving a SIGPIPE. If
+the other end can't handle that, be sure to read all the data before
+closing the pipe.
+
+Example:
+
+ open(OUTPUT, '|sort >foo') # pipe to sort
+ or die "Can't start sort: $!";
+ #... # print stuff to output
+ close OUTPUT # wait for sort to finish
+ or warn $! ? "Error closing sort pipe: $!"
+ : "Exit status $? from sort";
+ open(INPUT, 'foo') # get sort's results
+ or die "Can't open 'foo' for input: $!";
+
+FILEHANDLE may be an expression whose value can be used as an indirect
+filehandle, usually the real filehandle name.
+
+=item closedir DIRHANDLE
+X<closedir>
+
+Closes a directory opened by C<opendir> and returns the success of that
+system call.
+
+=item connect SOCKET,NAME
+X<connect>
+
+Attempts to connect to a remote socket, just like connect(2).
+Returns true if it succeeded, false otherwise. NAME should be a
+packed address of the appropriate type for the socket. See the examples in
+L<perlipc/"Sockets: Client/Server Communication">.
+
+=item continue BLOCK
+X<continue>
+
+=item continue
+
+C<continue> is actually a flow control statement rather than a function. If
+there is a C<continue> BLOCK attached to a BLOCK (typically in a C<while> or
+C<foreach>), it is always executed just before the conditional is about to
+be evaluated again, just like the third part of a C<for> loop in C. Thus
+it can be used to increment a loop variable, even when the loop has been
+continued via the C<next> statement (which is similar to the C C<continue>
+statement).
+
+C<last>, C<next>, or C<redo> may appear within a C<continue>
+block; C<last> and C<redo> behave as if they had been executed within
+the main block. So will C<next>, but since it will execute a C<continue>
+block, it may be more entertaining.
+
+ while (EXPR) {
+ ### redo always comes here
+ do_something;
+ } continue {
+ ### next always comes here
+ do_something_else;
+ # then back the top to re-check EXPR
+ }
+ ### last always comes here
+
+Omitting the C<continue> section is equivalent to using an
+empty one, logically enough, so C<next> goes directly back
+to check the condition at the top of the loop.
+
+If the C<"switch"> feature is enabled, C<continue> is also a
+function that exits the current C<when> (or C<default>) block and
+falls through to the next one. See L<feature> and
+L<perlsyn/"Switch statements"> for more information.
+
+
+=item cos EXPR
+X<cos> X<cosine> X<acos> X<arccosine>
+
+=item cos
+
+Returns the cosine of EXPR (expressed in radians). If EXPR is omitted,
+takes cosine of C<$_>.
+
+For the inverse cosine operation, you may use the C<Math::Trig::acos()>
+function, or use this relation:
+
+ sub acos { atan2( sqrt(1 - $_[0] * $_[0]), $_[0] ) }
+
+=item crypt PLAINTEXT,SALT
+X<crypt> X<digest> X<hash> X<salt> X<plaintext> X<password>
+X<decrypt> X<cryptography> X<passwd> X<encrypt>
+
+Creates a digest string exactly like the crypt(3) function in the C
+library (assuming that you actually have a version there that has not
+been extirpated as a potential munition).
+
+crypt() is a one-way hash function. The PLAINTEXT and SALT is turned
+into a short string, called a digest, which is returned. The same
+PLAINTEXT and SALT will always return the same string, but there is no
+(known) way to get the original PLAINTEXT from the hash. Small
+changes in the PLAINTEXT or SALT will result in large changes in the
+digest.
+
+There is no decrypt function. This function isn't all that useful for
+cryptography (for that, look for F<Crypt> modules on your nearby CPAN
+mirror) and the name "crypt" is a bit of a misnomer. Instead it is
+primarily used to check if two pieces of text are the same without
+having to transmit or store the text itself. An example is checking
+if a correct password is given. The digest of the password is stored,
+not the password itself. The user types in a password that is
+crypt()'d with the same salt as the stored digest. If the two digests
+match the password is correct.
+
+When verifying an existing digest string you should use the digest as
+the salt (like C<crypt($plain, $digest) eq $digest>). The SALT used
+to create the digest is visible as part of the digest. This ensures
+crypt() will hash the new string with the same salt as the digest.
+This allows your code to work with the standard L<crypt|/crypt> and
+with more exotic implementations. In other words, do not assume
+anything about the returned string itself, or how many bytes in the
+digest matter.
+
+Traditionally the result is a string of 13 bytes: two first bytes of
+the salt, followed by 11 bytes from the set C<[./0-9A-Za-z]>, and only
+the first eight bytes of PLAINTEXT mattered. But alternative
+hashing schemes (like MD5), higher level security schemes (like C2),
+and implementations on non-Unix platforms may produce different
+strings.
+
+When choosing a new salt create a random two character string whose
+characters come from the set C<[./0-9A-Za-z]> (like C<join '', ('.',
+'/', 0..9, 'A'..'Z', 'a'..'z')[rand 64, rand 64]>). This set of
+characters is just a recommendation; the characters allowed in
+the salt depend solely on your system's crypt library, and Perl can't
+restrict what salts C<crypt()> accepts.
+
+Here's an example that makes sure that whoever runs this program knows
+their password:
+
+ $pwd = (getpwuid($<))[1];
+
+ system "stty -echo";
+ print "Password: ";
+ chomp($word = <STDIN>);
+ print "\n";
+ system "stty echo";
+
+ if (crypt($word, $pwd) ne $pwd) {
+ die "Sorry...\n";
+ } else {
+ print "ok\n";
+ }
+
+Of course, typing in your own password to whoever asks you
+for it is unwise.
+
+The L<crypt|/crypt> function is unsuitable for hashing large quantities
+of data, not least of all because you can't get the information
+back. Look at the L<Digest> module for more robust algorithms.
+
+If using crypt() on a Unicode string (which I<potentially> has
+characters with codepoints above 255), Perl tries to make sense
+of the situation by trying to downgrade (a copy of the string)
+the string back to an eight-bit byte string before calling crypt()
+(on that copy). If that works, good. If not, crypt() dies with
+C<Wide character in crypt>.
+
+=item dbmclose HASH
+X<dbmclose>
+
+[This function has been largely superseded by the C<untie> function.]
+
+Breaks the binding between a DBM file and a hash.
+
+=item dbmopen HASH,DBNAME,MASK
+X<dbmopen> X<dbm> X<ndbm> X<sdbm> X<gdbm>
+
+[This function has been largely superseded by the C<tie> function.]
+
+This binds a dbm(3), ndbm(3), sdbm(3), gdbm(3), or Berkeley DB file to a
+hash. HASH is the name of the hash. (Unlike normal C<open>, the first
+argument is I<not> a filehandle, even though it looks like one). DBNAME
+is the name of the database (without the F<.dir> or F<.pag> extension if
+any). If the database does not exist, it is created with protection
+specified by MASK (as modified by the C<umask>). If your system supports
+only the older DBM functions, you may make only one C<dbmopen> call in your
+program. In older versions of Perl, if your system had neither DBM nor
+ndbm, calling C<dbmopen> produced a fatal error; it now falls back to
+sdbm(3).
+
+If you don't have write access to the DBM file, you can only read hash
+variables, not set them. If you want to test whether you can write,
+either use file tests or try setting a dummy hash entry inside an C<eval>
+to trap the error.
+
+Note that functions such as C<keys> and C<values> may return huge lists
+when used on large DBM files. You may prefer to use the C<each>
+function to iterate over large DBM files. Example:
+
+ # print out history file offsets
+ dbmopen(%HIST,'/usr/lib/news/history',0666);
+ while (($key,$val) = each %HIST) {
+ print $key, ' = ', unpack('L',$val), "\n";
+ }
+ dbmclose(%HIST);
+
+See also L<AnyDBM_File> for a more general description of the pros and
+cons of the various dbm approaches, as well as L<DB_File> for a particularly
+rich implementation.
+
+You can control which DBM library you use by loading that library
+before you call dbmopen():
+
+ use DB_File;
+ dbmopen(%NS_Hist, "$ENV{HOME}/.netscape/history.db")
+ or die "Can't open netscape history file: $!";
+
+=item defined EXPR
+X<defined> X<undef> X<undefined>
+
+=item defined
+
+Returns a Boolean value telling whether EXPR has a value other than
+the undefined value C<undef>. If EXPR is not present, C<$_> is
+checked.
+
+Many operations return C<undef> to indicate failure, end of file,
+system error, uninitialized variable, and other exceptional
+conditions. This function allows you to distinguish C<undef> from
+other values. (A simple Boolean test will not distinguish among
+C<undef>, zero, the empty string, and C<"0">, which are all equally
+false.) Note that since C<undef> is a valid scalar, its presence
+doesn't I<necessarily> indicate an exceptional condition: C<pop>
+returns C<undef> when its argument is an empty array, I<or> when the
+element to return happens to be C<undef>.
+
+You may also use C<defined(&func)> to check whether subroutine C<&func>
+has ever been defined. The return value is unaffected by any forward
+declarations of C<&func>. A subroutine that is not defined
+may still be callable: its package may have an C<AUTOLOAD> method that
+makes it spring into existence the first time that it is called; see
+L<perlsub>.
+
+Use of C<defined> on aggregates (hashes and arrays) is deprecated. It
+used to report whether memory for that aggregate has ever been
+allocated. This behavior may disappear in future versions of Perl.
+You should instead use a simple test for size:
+
+ if (@an_array) { print "has array elements\n" }
+ if (%a_hash) { print "has hash members\n" }
+
+When used on a hash element, it tells you whether the value is defined,
+not whether the key exists in the hash. Use L</exists> for the latter
+purpose.
+
+Examples:
+
+ print if defined $switch{'D'};
+ print "$val\n" while defined($val = pop(@ary));
+ die "Can't readlink $sym: $!"
+ unless defined($value = readlink $sym);
+ sub foo { defined &$bar ? &$bar(@_) : die "No bar"; }
+ $debugging = 0 unless defined $debugging;
+
+Note: Many folks tend to overuse C<defined>, and then are surprised to
+discover that the number C<0> and C<""> (the zero-length string) are, in fact,
+defined values. For example, if you say
+
+ "ab" =~ /a(.*)b/;
+
+The pattern match succeeds and C<$1> is defined, although it
+matched "nothing". It didn't really fail to match anything. Rather, it
+matched something that happened to be zero characters long. This is all
+very above-board and honest. When a function returns an undefined value,
+it's an admission that it couldn't give you an honest answer. So you
+should use C<defined> only when questioning the integrity of what
+you're trying to do. At other times, a simple comparison to C<0> or C<""> is
+what you want.
+
+See also L</undef>, L</exists>, L</ref>.
+
+=item delete EXPR
+X<delete>
+
+Given an expression that specifies an element or slice of a hash, C<delete>
+deletes the specified elements from that hash so that exists() on that element
+no longer returns true. Setting a hash element to the undefined value does
+not remove its key, but deleting it does; see L</exists>.
+
+It returns the value or values deleted in list context, or the last such
+element in scalar context. The return list's length always matches that of
+the argument list: deleting non-existent elements returns the undefined value
+in their corresponding positions.
+
+delete() may also be used on arrays and array slices, but its behavior is less
+straightforward. Although exists() will return false for deleted entries,
+deleting array elements never changes indices of existing values; use shift()
+or splice() for that. However, if all deleted elements fall at the end of an
+array, the array's size shrinks to the position of the highest element that
+still tests true for exists(), or to 0 if none do.
+
+B<Be aware> that calling delete on array values is deprecated and likely to
+be removed in a future version of Perl.
+
+Deleting from C<%ENV> modifies the environment. Deleting from a hash tied to
+a DBM file deletes the entry from the DBM file. Deleting from a C<tied> hash
+or array may not necessarily return anything; it depends on the implementation
+of the C<tied> package's DELETE method, which may do whatever it pleases.
+
+The C<delete local EXPR> construct localizes the deletion to the current
+block at run time. Until the block exits, elements locally deleted
+temporarily no longer exist. See L<perlsub/"Localized deletion of elements
+of composite types">.
+
+ %hash = (foo => 11, bar => 22, baz => 33);
+ $scalar = delete $hash{foo}; # $scalar is 11
+ $scalar = delete @hash{qw(foo bar)}; # $scalar is 22
+ @array = delete @hash{qw(foo bar baz)}; # @array is (undef,undef,33)
+
+The following (inefficiently) deletes all the values of %HASH and @ARRAY:
+
+ foreach $key (keys %HASH) {
+ delete $HASH{$key};
+ }
+
+ foreach $index (0 .. $#ARRAY) {
+ delete $ARRAY[$index];
+ }
+
+And so do these:
+
+ delete @HASH{keys %HASH};
+
+ delete @ARRAY[0 .. $#ARRAY];
+
+But both are slower than assigning the empty list
+or undefining %HASH or @ARRAY, which is the customary
+way to empty out an aggregate:
+
+ %HASH = (); # completely empty %HASH
+ undef %HASH; # forget %HASH ever existed
+
+ @ARRAY = (); # completely empty @ARRAY
+ undef @ARRAY; # forget @ARRAY ever existed
+
+The EXPR can be arbitrarily complicated provided its
+final operation is an element or slice of an aggregate:
+
+ delete $ref->[$x][$y]{$key};
+ delete @{$ref->[$x][$y]}{$key1, $key2, @morekeys};
+
+ delete $ref->[$x][$y][$index];
+ delete @{$ref->[$x][$y]}[$index1, $index2, @moreindices];
+
+=item die LIST
+X<die> X<throw> X<exception> X<raise> X<$@> X<abort>
+
+C<die> raises an exception. Inside an C<eval> the error message is stuffed
+into C<$@> and the C<eval> is terminated with the undefined value.
+If the exception is outside of all enclosing C<eval>s, then the uncaught
+exception prints LIST to C<STDERR> and exits with a non-zero value. If you
+need to exit the process with a specific exit code, see L<exit>.
+
+Equivalent examples:
+
+ die "Can't cd to spool: $!\n" unless chdir '/usr/spool/news';
+ chdir '/usr/spool/news' or die "Can't cd to spool: $!\n"
+
+If the last element of LIST does not end in a newline, the current
+script line number and input line number (if any) are also printed,
+and a newline is supplied. Note that the "input line number" (also
+known as "chunk") is subject to whatever notion of "line" happens to
+be currently in effect, and is also available as the special variable
+C<$.>. See L<perlvar/"$/"> and L<perlvar/"$.">.
+
+Hint: sometimes appending C<", stopped"> to your message will cause it
+to make better sense when the string C<"at foo line 123"> is appended.
+Suppose you are running script "canasta".
+
+ die "/etc/games is no good";
+ die "/etc/games is no good, stopped";
+
+produce, respectively
+
+ /etc/games is no good at canasta line 123.
+ /etc/games is no good, stopped at canasta line 123.
+
+If the output is empty and C<$@> already contains a value (typically from a
+previous eval) that value is reused after appending C<"\t...propagated">.
+This is useful for propagating exceptions:
+
+ eval { ... };
+ die unless $@ =~ /Expected exception/;
+
+If the output is empty and C<$@> contains an object reference that has a
+C<PROPAGATE> method, that method will be called with additional file
+and line number parameters. The return value replaces the value in
+C<$@>. i.e., as if C<< $@ = eval { $@->PROPAGATE(__FILE__, __LINE__) }; >>
+were called.
+
+If C<$@> is empty then the string C<"Died"> is used.
+
+If an uncaught exception results in interpreter exit, the exit code is
+determined from the values of C<$!> and C<$?> with this pseudocode:
+
+ exit $! if $!; # errno
+ exit $? >> 8 if $? >> 8; # child exit status
+ exit 255; # last resort
+
+The intent is to squeeze as much possible information about the likely cause
+into the limited space of the system exit code. However, as C<$!> is the value
+of C's C<errno>, which can be set by any system call, this means that the value
+of the exit code used by C<die> can be non-predictable, so should not be relied
+upon, other than to be non-zero.
+
+You can also call C<die> with a reference argument, and if this is trapped
+within an C<eval>, C<$@> contains that reference. This permits more
+elaborate exception handling using objects that maintain arbitrary state
+about the exception. Such a scheme is sometimes preferable to matching
+particular string values of C<$@> with regular expressions. Because C<$@>
+is a global variable and C<eval> may be used within object implementations,
+be careful that analyzing the error object doesn't replace the reference in
+the global variable. It's easiest to make a local copy of the reference
+before any manipulations. Here's an example:
+
+ use Scalar::Util "blessed";
+
+ eval { ... ; die Some::Module::Exception->new( FOO => "bar" ) };
+ if (my $ev_err = $@) {
+ if (blessed($ev_err) && $ev_err->isa("Some::Module::Exception")) {
+ # handle Some::Module::Exception
+ }
+ else {
+ # handle all other possible exceptions
+ }
+ }
+
+Because Perl stringifies uncaught exception messages before display,
+you'll probably want to overload stringification operations on
+exception objects. See L<overload> for details about that.
+
+You can arrange for a callback to be run just before the C<die>
+does its deed, by setting the C<$SIG{__DIE__}> hook. The associated
+handler is called with the error text and can change the error
+message, if it sees fit, by calling C<die> again. See
+L<perlvar/$SIG{expr}> for details on setting C<%SIG> entries, and
+L<"eval BLOCK"> for some examples. Although this feature was
+to be run only right before your program was to exit, this is not
+currently so: the C<$SIG{__DIE__}> hook is currently called
+even inside eval()ed blocks/strings! If one wants the hook to do
+nothing in such situations, put
+
+ die @_ if $^S;
+
+as the first line of the handler (see L<perlvar/$^S>). Because
+this promotes strange action at a distance, this counterintuitive
+behavior may be fixed in a future release.
+
+See also exit(), warn(), and the Carp module.
+
+=item do BLOCK
+X<do> X<block>
+
+Not really a function. Returns the value of the last command in the
+sequence of commands indicated by BLOCK. When modified by the C<while> or
+C<until> loop modifier, executes the BLOCK once before testing the loop
+condition. (On other statements the loop modifiers test the conditional
+first.)
+
+C<do BLOCK> does I<not> count as a loop, so the loop control statements
+C<next>, C<last>, or C<redo> cannot be used to leave or restart the block.
+See L<perlsyn> for alternative strategies.
+
+=item do SUBROUTINE(LIST)
+X<do>
+
+This form of subroutine call is deprecated. See L<perlsub>.
+
+=item do EXPR
+X<do>
+
+Uses the value of EXPR as a filename and executes the contents of the
+file as a Perl script.
+
+ do 'stat.pl';
+
+is just like
+
+ eval `cat stat.pl`;
+
+except that it's more efficient and concise, keeps track of the current
+filename for error messages, searches the @INC directories, and updates
+C<%INC> if the file is found. See L<perlvar/Predefined Names> for these
+variables. It also differs in that code evaluated with C<do FILENAME>
+cannot see lexicals in the enclosing scope; C<eval STRING> does. It's the
+same, however, in that it does reparse the file every time you call it,
+so you probably don't want to do this inside a loop.
+
+If C<do> cannot read the file, it returns undef and sets C<$!> to the
+error. If C<do> can read the file but cannot compile it, it
+returns undef and sets an error message in C<$@>. If the file is
+successfully compiled, C<do> returns the value of the last expression
+evaluated.
+
+Inclusion of library modules is better done with the
+C<use> and C<require> operators, which also do automatic error checking
+and raise an exception if there's a problem.
+
+You might like to use C<do> to read in a program configuration
+file. Manual error checking can be done this way:
+
+ # read in config files: system first, then user
+ for $file ("/share/prog/defaults.rc",
+ "$ENV{HOME}/.someprogrc")
+ {
+ unless ($return = do $file) {
+ warn "couldn't parse $file: $@" if $@;
+ warn "couldn't do $file: $!" unless defined $return;
+ warn "couldn't run $file" unless $return;
+ }
+ }
+
+=item dump LABEL
+X<dump> X<core> X<undump>
+
+=item dump
+
+This function causes an immediate core dump. See also the B<-u>
+command-line switch in L<perlrun>, which does the same thing.
+Primarily this is so that you can use the B<undump> program (not
+supplied) to turn your core dump into an executable binary after
+having initialized all your variables at the beginning of the
+program. When the new binary is executed it will begin by executing
+a C<goto LABEL> (with all the restrictions that C<goto> suffers).
+Think of it as a goto with an intervening core dump and reincarnation.
+If C<LABEL> is omitted, restarts the program from the top.
+
+B<WARNING>: Any files opened at the time of the dump will I<not>
+be open any more when the program is reincarnated, with possible
+resulting confusion by Perl.
+
+This function is now largely obsolete, mostly because it's very hard to
+convert a core file into an executable. That's why you should now invoke
+it as C<CORE::dump()>, if you don't want to be warned against a possible
+typo.
+
+=item each HASH
+X<each> X<hash, iterator>
+
+=item each ARRAY
+X<array, iterator>
+
+When called in list context, returns a 2-element list consisting of the key
+and value for the next element of a hash, or the index and value for the
+next element of an array, so that you can iterate over it. When called in
+scalar context, returns only the key (not the value) in a hash, or the index
+in an array.
+
+Hash entries are returned in an apparently random order. The actual random
+order is subject to change in future versions of Perl, but it is
+guaranteed to be in the same order as either the C<keys> or C<values>
+function would produce on the same (unmodified) hash. Since Perl
+5.8.2 the ordering can be different even between different runs of Perl
+for security reasons (see L<perlsec/"Algorithmic Complexity Attacks">).
+
+After C<each> has returned all entries from the hash or array, the next
+call to C<each> returns the empty list in list context and C<undef> in
+scalar context. The next call following that one restarts iteration. Each
+hash or array has its own internal iterator, accessed by C<each>, C<keys>,
+and C<values>. The iterator is implicitly reset when C<each> has reached
+the end as just described; it can be explicitly reset by calling C<keys> or
+C<values> on the hash or array. If you add or delete a hash's elements
+while iterating over it, entries may be skipped or duplicated--so don't do
+that. Exception: It is always safe to delete the item most recently
+returned by C<each()>, so the following code works properly:
+
+ while (($key, $value) = each %hash) {
+ print $key, "\n";
+ delete $hash{$key}; # This is safe
+ }
+
+This prints out your environment like the printenv(1) program,
+but in a different order:
+
+ while (($key,$value) = each %ENV) {
+ print "$key=$value\n";
+ }
+
+See also C<keys>, C<values> and C<sort>.
+
+=item eof FILEHANDLE
+X<eof>
+X<end of file>
+X<end-of-file>
+
+=item eof ()
+
+=item eof
+
+Returns 1 if the next read on FILEHANDLE will return end of file, or if
+FILEHANDLE is not open. FILEHANDLE may be an expression whose value
+gives the real filehandle. (Note that this function actually
+reads a character and then C<ungetc>s it, so isn't useful in an
+interactive context.) Do not read from a terminal file (or call
+C<eof(FILEHANDLE)> on it) after end-of-file is reached. File types such
+as terminals may lose the end-of-file condition if you do.
+
+An C<eof> without an argument uses the last file read. Using C<eof()>
+with empty parentheses is different. It refers to the pseudo file
+formed from the files listed on the command line and accessed via the
+C<< <> >> operator. Since C<< <> >> isn't explicitly opened,
+as a normal filehandle is, an C<eof()> before C<< <> >> has been
+used will cause C<@ARGV> to be examined to determine if input is
+available. Similarly, an C<eof()> after C<< <> >> has returned
+end-of-file will assume you are processing another C<@ARGV> list,
+and if you haven't set C<@ARGV>, will read input from C<STDIN>;
+see L<perlop/"I/O Operators">.
+
+In a C<< while (<>) >> loop, C<eof> or C<eof(ARGV)> can be used to
+detect the end of each file, C<eof()> will detect the end of only the
+last file. Examples:
+
+ # reset line numbering on each input file
+ while (<>) {
+ next if /^\s*#/; # skip comments
+ print "$.\t$_";
+ } continue {
+ close ARGV if eof; # Not eof()!
+ }
+
+ # insert dashes just before last line of last file
+ while (<>) {
+ if (eof()) { # check for end of last file
+ print "--------------\n";
+ }
+ print;
+ last if eof(); # needed if we're reading from a terminal
+ }
+
+Practical hint: you almost never need to use C<eof> in Perl, because the
+input operators typically return C<undef> when they run out of data, or if
+there was an error.
+
+=item eval EXPR
+X<eval> X<try> X<catch> X<evaluate> X<parse> X<execute>
+X<error, handling> X<exception, handling>
+
+=item eval BLOCK
+
+=item eval
+
+In the first form, the return value of EXPR is parsed and executed as if it
+were a little Perl program. The value of the expression (which is itself
+determined within scalar context) is first parsed, and if there weren't any
+errors, executed in the lexical context of the current Perl program, so
+that any variable settings or subroutine and format definitions remain
+afterwards. Note that the value is parsed every time the C<eval> executes.
+If EXPR is omitted, evaluates C<$_>. This form is typically used to
+delay parsing and subsequent execution of the text of EXPR until run time.
+
+In the second form, the code within the BLOCK is parsed only once--at the
+same time the code surrounding the C<eval> itself was parsed--and executed
+within the context of the current Perl program. This form is typically
+used to trap exceptions more efficiently than the first (see below), while
+also providing the benefit of checking the code within BLOCK at compile
+time.
+
+The final semicolon, if any, may be omitted from the value of EXPR or within
+the BLOCK.
+
+In both forms, the value returned is the value of the last expression
+evaluated inside the mini-program; a return statement may be also used, just
+as with subroutines. The expression providing the return value is evaluated
+in void, scalar, or list context, depending on the context of the C<eval>
+itself. See L</wantarray> for more on how the evaluation context can be
+determined.
+
+If there is a syntax error or runtime error, or a C<die> statement is
+executed, C<eval> returns an undefined value in scalar context
+or an empty list in list context, and C<$@> is set to the
+error message. If there was no error, C<$@> is guaranteed to be the empty
+string. Beware that using C<eval> neither silences Perl from printing
+warnings to STDERR, nor does it stuff the text of warning messages into C<$@>.
+To do either of those, you have to use the C<$SIG{__WARN__}> facility, or
+turn off warnings inside the BLOCK or EXPR using S<C<no warnings 'all'>>.
+See L</warn>, L<perlvar>, L<warnings> and L<perllexwarn>.
+
+Note that, because C<eval> traps otherwise-fatal errors, it is useful for
+determining whether a particular feature (such as C<socket> or C<symlink>)
+is implemented. It is also Perl's exception trapping mechanism, where
+the die operator is used to raise exceptions.
+
+If you want to trap errors when loading an XS module, some problems with
+the binary interface (such as Perl version skew) may be fatal even with
+C<eval> unless C<$ENV{PERL_DL_NONLAZY}> is set. See L<perlrun>.
+
+If the code to be executed doesn't vary, you may use the eval-BLOCK
+form to trap run-time errors without incurring the penalty of
+recompiling each time. The error, if any, is still returned in C<$@>.
+Examples:
+
+ # make divide-by-zero nonfatal
+ eval { $answer = $a / $b; }; warn $@ if $@;
+
+ # same thing, but less efficient
+ eval '$answer = $a / $b'; warn $@ if $@;
+
+ # a compile-time error
+ eval { $answer = }; # WRONG
+
+ # a run-time error
+ eval '$answer ='; # sets $@
+
+Using the C<eval{}> form as an exception trap in libraries does have some
+issues. Due to the current arguably broken state of C<__DIE__> hooks, you
+may wish not to trigger any C<__DIE__> hooks that user code may have installed.
+You can use the C<local $SIG{__DIE__}> construct for this purpose,
+as this example shows:
+
+ # a private exception trap for divide-by-zero
+ eval { local $SIG{'__DIE__'}; $answer = $a / $b; };
+ warn $@ if $@;
+
+This is especially significant, given that C<__DIE__> hooks can call
+C<die> again, which has the effect of changing their error messages:
+
+ # __DIE__ hooks may modify error messages
+ {
+ local $SIG{'__DIE__'} =
+ sub { (my $x = $_[0]) =~ s/foo/bar/g; die $x };
+ eval { die "foo lives here" };
+ print $@ if $@; # prints "bar lives here"
+ }
+
+Because this promotes action at a distance, this counterintuitive behavior
+may be fixed in a future release.
+
+With an C<eval>, you should be especially careful to remember what's
+being looked at when:
+
+ eval $x; # CASE 1
+ eval "$x"; # CASE 2
+
+ eval '$x'; # CASE 3
+ eval { $x }; # CASE 4
+
+ eval "\$$x++"; # CASE 5
+ $$x++; # CASE 6
+
+Cases 1 and 2 above behave identically: they run the code contained in
+the variable $x. (Although case 2 has misleading double quotes making
+the reader wonder what else might be happening (nothing is).) Cases 3
+and 4 likewise behave in the same way: they run the code C<'$x'>, which
+does nothing but return the value of $x. (Case 4 is preferred for
+purely visual reasons, but it also has the advantage of compiling at
+compile-time instead of at run-time.) Case 5 is a place where
+normally you I<would> like to use double quotes, except that in this
+particular situation, you can just use symbolic references instead, as
+in case 6.
+
+The assignment to C<$@> occurs before restoration of localised variables,
+which means a temporary is required if you want to mask some but not all
+errors:
+
+ # alter $@ on nefarious repugnancy only
+ {
+ my $e;
+ {
+ local $@; # protect existing $@
+ eval { test_repugnancy() };
+ # $@ =~ /nefarious/ and die $@; # DOES NOT WORK
+ $@ =~ /nefarious/ and $e = $@;
+ }
+ die $e if defined $e
+ }
+
+C<eval BLOCK> does I<not> count as a loop, so the loop control statements
+C<next>, C<last>, or C<redo> cannot be used to leave or restart the block.
+
+An C<eval ''> executed within the C<DB> package doesn't see the usual
+surrounding lexical scope, but rather the scope of the first non-DB piece
+of code that called it. You don't normally need to worry about this unless
+you are writing a Perl debugger.
+
+=item exec LIST
+X<exec> X<execute>
+
+=item exec PROGRAM LIST
+
+The C<exec> function executes a system command I<and never returns>;
+use C<system> instead of C<exec> if you want it to return. It fails and
+returns false only if the command does not exist I<and> it is executed
+directly instead of via your system's command shell (see below).
+
+Since it's a common mistake to use C<exec> instead of C<system>, Perl
+warns you if there is a following statement that isn't C<die>, C<warn>,
+or C<exit> (if C<-w> is set--but you always do that, right?). If you
+I<really> want to follow an C<exec> with some other statement, you
+can use one of these styles to avoid the warning:
+
+ exec ('foo') or print STDERR "couldn't exec foo: $!";
+ { exec ('foo') }; print STDERR "couldn't exec foo: $!";
+
+If there is more than one argument in LIST, or if LIST is an array
+with more than one value, calls execvp(3) with the arguments in LIST.
+If there is only one scalar argument or an array with one element in it,
+the argument is checked for shell metacharacters, and if there are any,
+the entire argument is passed to the system's command shell for parsing
+(this is C</bin/sh -c> on Unix platforms, but varies on other platforms).
+If there are no shell metacharacters in the argument, it is split into
+words and passed directly to C<execvp>, which is more efficient.
+Examples:
+
+ exec '/bin/echo', 'Your arguments are: ', @ARGV;
+ exec "sort $outfile | uniq";
+
+If you don't really want to execute the first argument, but want to lie
+to the program you are executing about its own name, you can specify
+the program you actually want to run as an "indirect object" (without a
+comma) in front of the LIST. (This always forces interpretation of the
+LIST as a multivalued list, even if there is only a single scalar in
+the list.) Example:
+
+ $shell = '/bin/csh';
+ exec $shell '-sh'; # pretend it's a login shell
+
+or, more directly,
+
+ exec {'/bin/csh'} '-sh'; # pretend it's a login shell
+
+When the arguments get executed via the system shell, results are
+subject to its quirks and capabilities. See L<perlop/"`STRING`">
+for details.
+
+Using an indirect object with C<exec> or C<system> is also more
+secure. This usage (which also works fine with system()) forces
+interpretation of the arguments as a multivalued list, even if the
+list had just one argument. That way you're safe from the shell
+expanding wildcards or splitting up words with whitespace in them.
+
+ @args = ( "echo surprise" );
+
+ exec @args; # subject to shell escapes
+ # if @args == 1
+ exec { $args[0] } @args; # safe even with one-arg list
+
+The first version, the one without the indirect object, ran the I<echo>
+program, passing it C<"surprise"> an argument. The second version didn't;
+it tried to run a program named I<"echo surprise">, didn't find it, and set
+C<$?> to a non-zero value indicating failure.
+
+Beginning with v5.6.0, Perl attempts to flush all files opened for
+output before the exec, but this may not be supported on some platforms
+(see L<perlport>). To be safe, you may need to set C<$|> ($AUTOFLUSH
+in English) or call the C<autoflush()> method of C<IO::Handle> on any
+open handles to avoid lost output.
+
+Note that C<exec> will not call your C<END> blocks, nor will it invoke
+C<DESTROY> methods on your objects.
+
+=item exists EXPR
+X<exists> X<autovivification>
+
+Given an expression that specifies an element of a hash, returns true if the
+specified element in the hash has ever been initialized, even if the
+corresponding value is undefined.
+
+ print "Exists\n" if exists $hash{$key};
+ print "Defined\n" if defined $hash{$key};
+ print "True\n" if $hash{$key};
+
+exists may also be called on array elements, but its behavior is much less
+obvious, and is strongly tied to the use of L</delete> on arrays. B<Be aware>
+that calling exists on array values is deprecated and likely to be removed in
+a future version of Perl.
+
+ print "Exists\n" if exists $array[$index];
+ print "Defined\n" if defined $array[$index];
+ print "True\n" if $array[$index];
+
+A hash or array element can be true only if it's defined, and defined if
+it exists, but the reverse doesn't necessarily hold true.
+
+Given an expression that specifies the name of a subroutine,
+returns true if the specified subroutine has ever been declared, even
+if it is undefined. Mentioning a subroutine name for exists or defined
+does not count as declaring it. Note that a subroutine that does not
+exist may still be callable: its package may have an C<AUTOLOAD>
+method that makes it spring into existence the first time that it is
+called; see L<perlsub>.
+
+ print "Exists\n" if exists &subroutine;
+ print "Defined\n" if defined &subroutine;
+
+Note that the EXPR can be arbitrarily complicated as long as the final
+operation is a hash or array key lookup or subroutine name:
+
+ if (exists $ref->{A}->{B}->{$key}) { }
+ if (exists $hash{A}{B}{$key}) { }
+
+ if (exists $ref->{A}->{B}->[$ix]) { }
+ if (exists $hash{A}{B}[$ix]) { }
+
+ if (exists &{$ref->{A}{B}{$key}}) { }
+
+Although the mostly deeply nested array or hash will not spring into
+existence just because its existence was tested, any intervening ones will.
+Thus C<< $ref->{"A"} >> and C<< $ref->{"A"}->{"B"} >> will spring
+into existence due to the existence test for the $key element above.
+This happens anywhere the arrow operator is used, including even here:
+
+ undef $ref;
+ if (exists $ref->{"Some key"}) { }
+ print $ref; # prints HASH(0x80d3d5c)
+
+This surprising autovivification in what does not at first--or even
+second--glance appear to be an lvalue context may be fixed in a future
+release.
+
+Use of a subroutine call, rather than a subroutine name, as an argument
+to exists() is an error.
+
+ exists &sub; # OK
+ exists &sub(); # Error
+
+=item exit EXPR
+X<exit> X<terminate> X<abort>
+
+=item exit
+
+Evaluates EXPR and exits immediately with that value. Example:
+
+ $ans = <STDIN>;
+ exit 0 if $ans =~ /^[Xx]/;
+
+See also C<die>. If EXPR is omitted, exits with C<0> status. The only
+universally recognized values for EXPR are C<0> for success and C<1>
+for error; other values are subject to interpretation depending on the
+environment in which the Perl program is running. For example, exiting
+69 (EX_UNAVAILABLE) from a I<sendmail> incoming-mail filter will cause
+the mailer to return the item undelivered, but that's not true everywhere.
+
+Don't use C<exit> to abort a subroutine if there's any chance that
+someone might want to trap whatever error happened. Use C<die> instead,
+which can be trapped by an C<eval>.
+
+The exit() function does not always exit immediately. It calls any
+defined C<END> routines first, but these C<END> routines may not
+themselves abort the exit. Likewise any object destructors that need to
+be called are called before the real exit. If this is a problem, you
+can call C<POSIX:_exit($status)> to avoid END and destructor processing.
+See L<perlmod> for details.
+
+=item exp EXPR
+X<exp> X<exponential> X<antilog> X<antilogarithm> X<e>
+
+=item exp
+
+Returns I<e> (the natural logarithm base) to the power of EXPR.
+If EXPR is omitted, gives C<exp($_)>.
+
+=item fcntl FILEHANDLE,FUNCTION,SCALAR
+X<fcntl>
+
+Implements the fcntl(2) function. You'll probably have to say
+
+ use Fcntl;
+
+first to get the correct constant definitions. Argument processing and
+value returned work just like C<ioctl> below.
+For example:
+
+ use Fcntl;
+ fcntl($filehandle, F_GETFL, $packed_return_buffer)
+ or die "can't fcntl F_GETFL: $!";
+
+You don't have to check for C<defined> on the return from C<fcntl>.
+Like C<ioctl>, it maps a C<0> return from the system call into
+C<"0 but true"> in Perl. This string is true in boolean context and C<0>
+in numeric context. It is also exempt from the normal B<-w> warnings
+on improper numeric conversions.
+
+Note that C<fcntl> raises an exception if used on a machine that
+doesn't implement fcntl(2). See the Fcntl module or your fcntl(2)
+manpage to learn what functions are available on your system.
+
+Here's an example of setting a filehandle named C<REMOTE> to be
+non-blocking at the system level. You'll have to negotiate C<$|>
+on your own, though.
+
+ use Fcntl qw(F_GETFL F_SETFL O_NONBLOCK);
+
+ $flags = fcntl(REMOTE, F_GETFL, 0)
+ or die "Can't get flags for the socket: $!\n";
+
+ $flags = fcntl(REMOTE, F_SETFL, $flags | O_NONBLOCK)
+ or die "Can't set flags for the socket: $!\n";
+
+=item fileno FILEHANDLE
+X<fileno>
+
+Returns the file descriptor for a filehandle, or undefined if the
+filehandle is not open. This is mainly useful for constructing
+bitmaps for C<select> and low-level POSIX tty-handling operations.
+If FILEHANDLE is an expression, the value is taken as an indirect
+filehandle, generally its name.
+
+You can use this to find out whether two handles refer to the
+same underlying descriptor:
+
+ if (fileno(THIS) == fileno(THAT)) {
+ print "THIS and THAT are dups\n";
+ }
+
+(Filehandles connected to memory objects via new features of C<open> may
+return undefined even though they are open.)
+
+
+=item flock FILEHANDLE,OPERATION
+X<flock> X<lock> X<locking>
+
+Calls flock(2), or an emulation of it, on FILEHANDLE. Returns true
+for success, false on failure. Produces a fatal error if used on a
+machine that doesn't implement flock(2), fcntl(2) locking, or lockf(3).
+C<flock> is Perl's portable file locking interface, although it locks
+entire files only, not records.
+
+Two potentially non-obvious but traditional C<flock> semantics are
+that it waits indefinitely until the lock is granted, and that its locks
+B<merely advisory>. Such discretionary locks are more flexible, but offer
+fewer guarantees. This means that programs that do not also use C<flock>
+may modify files locked with C<flock>. See L<perlport>,
+your port's specific documentation, or your system-specific local manpages
+for details. It's best to assume traditional behavior if you're writing
+portable programs. (But if you're not, you should as always feel perfectly
+free to write for your own system's idiosyncrasies (sometimes called
+"features"). Slavish adherence to portability concerns shouldn't get
+in the way of your getting your job done.)
+
+OPERATION is one of LOCK_SH, LOCK_EX, or LOCK_UN, possibly combined with
+LOCK_NB. These constants are traditionally valued 1, 2, 8 and 4, but
+you can use the symbolic names if you import them from the Fcntl module,
+either individually, or as a group using the ':flock' tag. LOCK_SH
+requests a shared lock, LOCK_EX requests an exclusive lock, and LOCK_UN
+releases a previously requested lock. If LOCK_NB is bitwise-or'ed with
+LOCK_SH or LOCK_EX then C<flock> returns immediately rather than blocking
+waiting for the lock; check the return status to see if you got it.
+
+To avoid the possibility of miscoordination, Perl now flushes FILEHANDLE
+before locking or unlocking it.
+
+Note that the emulation built with lockf(3) doesn't provide shared
+locks, and it requires that FILEHANDLE be open with write intent. These
+are the semantics that lockf(3) implements. Most if not all systems
+implement lockf(3) in terms of fcntl(2) locking, though, so the
+differing semantics shouldn't bite too many people.
+
+Note that the fcntl(2) emulation of flock(3) requires that FILEHANDLE
+be open with read intent to use LOCK_SH and requires that it be open
+with write intent to use LOCK_EX.
+
+Note also that some versions of C<flock> cannot lock things over the
+network; you would need to use the more system-specific C<fcntl> for
+that. If you like you can force Perl to ignore your system's flock(2)
+function, and so provide its own fcntl(2)-based emulation, by passing
+the switch C<-Ud_flock> to the F<Configure> program when you configure
+Perl.
+
+Here's a mailbox appender for BSD systems.
+
+ use Fcntl qw(:flock SEEK_END); # import LOCK_* and SEEK_END constants
+
+ sub lock {
+ my ($fh) = @_;
+ flock($fh, LOCK_EX) or die "Cannot lock mailbox - $!\n";
+
+ # and, in case someone appended while we were waiting...
+ seek($fh, 0, SEEK_END) or die "Cannot seek - $!\n";
+ }
+
+ sub unlock {
+ my ($fh) = @_;
+ flock($fh, LOCK_UN) or die "Cannot unlock mailbox - $!\n";
+ }
+
+ open(my $mbox, ">>", "/usr/spool/mail/$ENV{'USER'}")
+ or die "Can't open mailbox: $!";
+
+ lock($mbox);
+ print $mbox $msg,"\n\n";
+ unlock($mbox);
+
+On systems that support a real flock(2), locks are inherited across fork()
+calls, whereas those that must resort to the more capricious fcntl(2)
+function lose their locks, making it seriously harder to write servers.
+
+See also L<DB_File> for other flock() examples.
+
+=item fork
+X<fork> X<child> X<parent>
+
+Does a fork(2) system call to create a new process running the
+same program at the same point. It returns the child pid to the
+parent process, C<0> to the child process, or C<undef> if the fork is
+unsuccessful. File descriptors (and sometimes locks on those descriptors)
+are shared, while everything else is copied. On most systems supporting
+fork(), great care has gone into making it extremely efficient (for
+example, using copy-on-write technology on data pages), making it the
+dominant paradigm for multitasking over the last few decades.
+
+Beginning with v5.6.0, Perl attempts to flush all files opened for
+output before forking the child process, but this may not be supported
+on some platforms (see L<perlport>). To be safe, you may need to set
+C<$|> ($AUTOFLUSH in English) or call the C<autoflush()> method of
+C<IO::Handle> on any open handles to avoid duplicate output.
+
+If you C<fork> without ever waiting on your children, you will
+accumulate zombies. On some systems, you can avoid this by setting
+C<$SIG{CHLD}> to C<"IGNORE">. See also L<perlipc> for more examples of
+forking and reaping moribund children.
+
+Note that if your forked child inherits system file descriptors like
+STDIN and STDOUT that are actually connected by a pipe or socket, even
+if you exit, then the remote server (such as, say, a CGI script or a
+backgrounded job launched from a remote shell) won't think you're done.
+You should reopen those to F</dev/null> if it's any issue.
+
+=item format
+X<format>
+
+Declare a picture format for use by the C<write> function. For
+example:
+
+ format Something =
+ Test: @<<<<<<<< @||||| @>>>>>
+ $str, $%, '$' . int($num)
+ .
+
+ $str = "widget";
+ $num = $cost/$quantity;
+ $~ = 'Something';
+ write;
+
+See L<perlform> for many details and examples.
+
+=item formline PICTURE,LIST
+X<formline>
+
+This is an internal function used by C<format>s, though you may call it,
+too. It formats (see L<perlform>) a list of values according to the
+contents of PICTURE, placing the output into the format output
+accumulator, C<$^A> (or C<$ACCUMULATOR> in English).
+Eventually, when a C<write> is done, the contents of
+C<$^A> are written to some filehandle. You could also read C<$^A>
+and then set C<$^A> back to C<"">. Note that a format typically
+does one C<formline> per line of form, but the C<formline> function itself
+doesn't care how many newlines are embedded in the PICTURE. This means
+that the C<~> and C<~~> tokens treat the entire PICTURE as a single line.
+You may therefore need to use multiple formlines to implement a single
+record format, just like the C<format> compiler.
+
+Be careful if you put double quotes around the picture, because an C<@>
+character may be taken to mean the beginning of an array name.
+C<formline> always returns true. See L<perlform> for other examples.
+
+=item getc FILEHANDLE
+X<getc> X<getchar> X<character> X<file, read>
+
+=item getc
+
+Returns the next character from the input file attached to FILEHANDLE,
+or the undefined value at end of file or if there was an error (in
+the latter case C<$!> is set). If FILEHANDLE is omitted, reads from
+STDIN. This is not particularly efficient. However, it cannot be
+used by itself to fetch single characters without waiting for the user
+to hit enter. For that, try something more like:
+
+ if ($BSD_STYLE) {
+ system "stty cbreak </dev/tty >/dev/tty 2>&1";
+ }
+ else {
+ system "stty", '-icanon', 'eol', "\001";
+ }
+
+ $key = getc(STDIN);
+
+ if ($BSD_STYLE) {
+ system "stty -cbreak </dev/tty >/dev/tty 2>&1";
+ }
+ else {
+ system 'stty', 'icanon', 'eol', '^@'; # ASCII NUL
+ }
+ print "\n";
+
+Determination of whether $BSD_STYLE should be set
+is left as an exercise to the reader.
+
+The C<POSIX::getattr> function can do this more portably on
+systems purporting POSIX compliance. See also the C<Term::ReadKey>
+module from your nearest CPAN site; details on CPAN can be found on
+L<perlmodlib/CPAN>.
+
+=item getlogin
+X<getlogin> X<login>
+
+This implements the C library function of the same name, which on most
+systems returns the current login from F</etc/utmp>, if any. If it
+returns the empty string, use C<getpwuid>.
+
+ $login = getlogin || getpwuid($<) || "Kilroy";
+
+Do not consider C<getlogin> for authentication: it is not as
+secure as C<getpwuid>.
+
+=item getpeername SOCKET
+X<getpeername> X<peer>
+
+Returns the packed sockaddr address of other end of the SOCKET connection.
+
+ use Socket;
+ $hersockaddr = getpeername(SOCK);
+ ($port, $iaddr) = sockaddr_in($hersockaddr);
+ $herhostname = gethostbyaddr($iaddr, AF_INET);
+ $herstraddr = inet_ntoa($iaddr);
+
+=item getpgrp PID
+X<getpgrp> X<group>
+
+Returns the current process group for the specified PID. Use
+a PID of C<0> to get the current process group for the
+current process. Will raise an exception if used on a machine that
+doesn't implement getpgrp(2). If PID is omitted, returns process
+group of current process. Note that the POSIX version of C<getpgrp>
+does not accept a PID argument, so only C<PID==0> is truly portable.
+
+=item getppid
+X<getppid> X<parent> X<pid>
+
+Returns the process id of the parent process.
+
+Note for Linux users: on Linux, the C functions C<getpid()> and
+C<getppid()> return different values from different threads. In order to
+be portable, this behavior is not reflected by the Perl-level function
+C<getppid()>, that returns a consistent value across threads. If you want
+to call the underlying C<getppid()>, you may use the CPAN module
+C<Linux::Pid>.
+
+=item getpriority WHICH,WHO
+X<getpriority> X<priority> X<nice>
+
+Returns the current priority for a process, a process group, or a user.
+(See C<getpriority(2)>.) Will raise a fatal exception if used on a
+machine that doesn't implement getpriority(2).
+
+=item getpwnam NAME
+X<getpwnam> X<getgrnam> X<gethostbyname> X<getnetbyname> X<getprotobyname>
+X<getpwuid> X<getgrgid> X<getservbyname> X<gethostbyaddr> X<getnetbyaddr>
+X<getprotobynumber> X<getservbyport> X<getpwent> X<getgrent> X<gethostent>
+X<getnetent> X<getprotoent> X<getservent> X<setpwent> X<setgrent> X<sethostent>
+X<setnetent> X<setprotoent> X<setservent> X<endpwent> X<endgrent> X<endhostent>
+X<endnetent> X<endprotoent> X<endservent>
+
+=item getgrnam NAME
+
+=item gethostbyname NAME
+
+=item getnetbyname NAME
+
+=item getprotobyname NAME
+
+=item getpwuid UID
+
+=item getgrgid GID
+
+=item getservbyname NAME,PROTO
+
+=item gethostbyaddr ADDR,ADDRTYPE
+
+=item getnetbyaddr ADDR,ADDRTYPE
+
+=item getprotobynumber NUMBER
+
+=item getservbyport PORT,PROTO
+
+=item getpwent
+
+=item getgrent
+
+=item gethostent
+
+=item getnetent
+
+=item getprotoent
+
+=item getservent
+
+=item setpwent
+
+=item setgrent
+
+=item sethostent STAYOPEN
+
+=item setnetent STAYOPEN
+
+=item setprotoent STAYOPEN
+
+=item setservent STAYOPEN
+
+=item endpwent
+
+=item endgrent
+
+=item endhostent
+
+=item endnetent
+
+=item endprotoent
+
+=item endservent
+
+These routines are the same as their counterparts in the
+system C library. In list context, the return values from the
+various get routines are as follows:
+
+ ($name,$passwd,$uid,$gid,
+ $quota,$comment,$gcos,$dir,$shell,$expire) = getpw*
+ ($name,$passwd,$gid,$members) = getgr*
+ ($name,$aliases,$addrtype,$length,@addrs) = gethost*
+ ($name,$aliases,$addrtype,$net) = getnet*
+ ($name,$aliases,$proto) = getproto*
+ ($name,$aliases,$port,$proto) = getserv*
+
+(If the entry doesn't exist you get an empty list.)
+
+The exact meaning of the $gcos field varies but it usually contains
+the real name of the user (as opposed to the login name) and other
+information pertaining to the user. Beware, however, that in many
+system users are able to change this information and therefore it
+cannot be trusted and therefore the $gcos is tainted (see
+L<perlsec>). The $passwd and $shell, user's encrypted password and
+login shell, are also tainted, because of the same reason.
+
+In scalar context, you get the name, unless the function was a
+lookup by name, in which case you get the other thing, whatever it is.
+(If the entry doesn't exist you get the undefined value.) For example:
+
+ $uid = getpwnam($name);
+ $name = getpwuid($num);
+ $name = getpwent();
+ $gid = getgrnam($name);
+ $name = getgrgid($num);
+ $name = getgrent();
+ #etc.
+
+In I<getpw*()> the fields $quota, $comment, and $expire are special
+in that they are unsupported on many systems. If the
+$quota is unsupported, it is an empty scalar. If it is supported, it
+usually encodes the disk quota. If the $comment field is unsupported,
+it is an empty scalar. If it is supported it usually encodes some
+administrative comment about the user. In some systems the $quota
+field may be $change or $age, fields that have to do with password
+aging. In some systems the $comment field may be $class. The $expire
+field, if present, encodes the expiration period of the account or the
+password. For the availability and the exact meaning of these fields
+in your system, please consult your getpwnam(3) documentation and your
+F<pwd.h> file. You can also find out from within Perl what your
+$quota and $comment fields mean and whether you have the $expire field
+by using the C<Config> module and the values C<d_pwquota>, C<d_pwage>,
+C<d_pwchange>, C<d_pwcomment>, and C<d_pwexpire>. Shadow password
+files are supported only if your vendor has implemented them in the
+intuitive fashion that calling the regular C library routines gets the
+shadow versions if you're running under privilege or if there exists
+the shadow(3) functions as found in System V (this includes Solaris
+and Linux.) Those systems that implement a proprietary shadow password
+facility are unlikely to be supported.
+
+The $members value returned by I<getgr*()> is a space separated list of
+the login names of the members of the group.
+
+For the I<gethost*()> functions, if the C<h_errno> variable is supported in
+C, it will be returned to you via C<$?> if the function call fails. The
+C<@addrs> value returned by a successful call is a list of raw
+addresses returned by the corresponding library call. In the
+Internet domain, each address is four bytes long; you can unpack it
+by saying something like:
+
+ ($a,$b,$c,$d) = unpack('W4',$addr[0]);
+
+The Socket library makes this slightly easier:
+
+ use Socket;
+ $iaddr = inet_aton("127.1"); # or whatever address
+ $name = gethostbyaddr($iaddr, AF_INET);
+
+ # or going the other way
+ $straddr = inet_ntoa($iaddr);
+
+In the opposite way, to resolve a hostname to the IP address
+you can write this:
+
+ use Socket;
+ $packed_ip = gethostbyname("www.perl.org");
+ if (defined $packed_ip) {
+ $ip_address = inet_ntoa($packed_ip);
+ }
+
+Make sure <gethostbyname()> is called in SCALAR context and that
+its return value is checked for definedness.
+
+If you get tired of remembering which element of the return list
+contains which return value, by-name interfaces are provided
+in standard modules: C<File::stat>, C<Net::hostent>, C<Net::netent>,
+C<Net::protoent>, C<Net::servent>, C<Time::gmtime>, C<Time::localtime>,
+and C<User::grent>. These override the normal built-ins, supplying
+versions that return objects with the appropriate names
+for each field. For example:
+
+ use File::stat;
+ use User::pwent;
+ $is_his = (stat($filename)->uid == pwent($whoever)->uid);
+
+Even though it looks like they're the same method calls (uid),
+they aren't, because a C<File::stat> object is different from
+a C<User::pwent> object.
+
+=item getsockname SOCKET
+X<getsockname>
+
+Returns the packed sockaddr address of this end of the SOCKET connection,
+in case you don't know the address because you have several different
+IPs that the connection might have come in on.
+
+ use Socket;
+ $mysockaddr = getsockname(SOCK);
+ ($port, $myaddr) = sockaddr_in($mysockaddr);
+ printf "Connect to %s [%s]\n",
+ scalar gethostbyaddr($myaddr, AF_INET),
+ inet_ntoa($myaddr);
+
+=item getsockopt SOCKET,LEVEL,OPTNAME
+X<getsockopt>
+
+Queries the option named OPTNAME associated with SOCKET at a given LEVEL.
+Options may exist at multiple protocol levels depending on the socket
+type, but at least the uppermost socket level SOL_SOCKET (defined in the
+C<Socket> module) will exist. To query options at another level the
+protocol number of the appropriate protocol controlling the option
+should be supplied. For example, to indicate that an option is to be
+interpreted by the TCP protocol, LEVEL should be set to the protocol
+number of TCP, which you can get using C<getprotobyname>.
+
+The function returns a packed string representing the requested socket
+option, or C<undef> on error, with the reason for the error placed in
+C<$!>). Just what is in the packed string depends on LEVEL and OPTNAME;
+consult getsockopt(2) for details. A common case is that the option is an
+integer, in which case the result is a packed integer, which you can decode
+using C<unpack> with the C<i> (or C<I>) format.
+
+An example to test whether Nagle's algorithm is turned on on a socket:
+
+ use Socket qw(:all);
+
+ defined(my $tcp = getprotobyname("tcp"))
+ or die "Could not determine the protocol number for tcp";
+ # my $tcp = IPPROTO_TCP; # Alternative
+ my $packed = getsockopt($socket, $tcp, TCP_NODELAY)
+ or die "getsockopt TCP_NODELAY: $!";
+ my $nodelay = unpack("I", $packed);
+ print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";
+
+
+=item glob EXPR
+X<glob> X<wildcard> X<filename, expansion> X<expand>
+
+=item glob
+
+In list context, returns a (possibly empty) list of filename expansions on
+the value of EXPR such as the standard Unix shell F</bin/csh> would do. In
+scalar context, glob iterates through such filename expansions, returning
+undef when the list is exhausted. This is the internal function
+implementing the C<< <*.c> >> operator, but you can use it directly. If
+EXPR is omitted, C<$_> is used. The C<< <*.c> >> operator is discussed in
+more detail in L<perlop/"I/O Operators">.
+
+Note that C<glob> splits its arguments on whitespace and treats
+each segment as separate pattern. As such, C<glob("*.c *.h")>
+matches all files with a F<.c> or F<.h> extension. The expression
+C<glob(".* *")> matchs all files in the current working directory.
+
+If non-empty braces are the only wildcard characters used in the
+C<glob>, no filenames are matched, but potentially many strings
+are returned. For example, this produces nine strings, one for
+each pairing of fruits and colors:
+
+ @many = glob "{apple,tomato,cherry}={green,yellow,red}";
+
+Beginning with v5.6.0, this operator is implemented using the standard
+C<File::Glob> extension. See L<File::Glob> for details, including
+C<bsd_glob> which does not treat whitespace as a pattern separator.
+
+=item gmtime EXPR
+X<gmtime> X<UTC> X<Greenwich>
+
+=item gmtime
+
+Works just like L<localtime> but the returned values are
+localized for the standard Greenwich time zone.
+
+Note: when called in list context, $isdst, the last value
+returned by gmtime is always C<0>. There is no
+Daylight Saving Time in GMT.
+
+See L<perlport/gmtime> for portability concerns.
+
+=item goto LABEL
+X<goto> X<jump> X<jmp>
+
+=item goto EXPR
+
+=item goto &NAME
+
+The C<goto-LABEL> form finds the statement labeled with LABEL and
+resumes execution there. It can't be used to get out of a block or
+subroutine given to C<sort>. It can be used to go almost anywhere
+else within the dynamic scope, including out of subroutines, but it's
+usually better to use some other construct such as C<last> or C<die>.
+The author of Perl has never felt the need to use this form of C<goto>
+(in Perl, that is; C is another matter). (The difference is that C
+does not offer named loops combined with loop control. Perl does, and
+this replaces most structured uses of C<goto> in other languages.)
+
+The C<goto-EXPR> form expects a label name, whose scope will be resolved
+dynamically. This allows for computed C<goto>s per FORTRAN, but isn't
+necessarily recommended if you're optimizing for maintainability:
+
+ goto ("FOO", "BAR", "GLARCH")[$i];
+
+Use of C<goto-LABEL> or C<goto-EXPR> to jump into a construct is
+deprecated and will issue a warning. Even then, it may not be used to
+go into any construct that requires initialization, such as a
+subroutine or a C<foreach> loop. It also can't be used to go into a
+construct that is optimized away.
+
+The C<goto-&NAME> form is quite different from the other forms of
+C<goto>. In fact, it isn't a goto in the normal sense at all, and
+doesn't have the stigma associated with other gotos. Instead, it
+exits the current subroutine (losing any changes set by local()) and
+immediately calls in its place the named subroutine using the current
+value of @_. This is used by C<AUTOLOAD> subroutines that wish to
+load another subroutine and then pretend that the other subroutine had
+been called in the first place (except that any modifications to C<@_>
+in the current subroutine are propagated to the other subroutine.)
+After the C<goto>, not even C<caller> will be able to tell that this
+routine was called first.
+
+NAME needn't be the name of a subroutine; it can be a scalar variable
+containing a code reference, or a block that evaluates to a code
+reference.
+
+=item grep BLOCK LIST
+X<grep>
+
+=item grep EXPR,LIST
+
+This is similar in spirit to, but not the same as, grep(1) and its
+relatives. In particular, it is not limited to using regular expressions.
+
+Evaluates the BLOCK or EXPR for each element of LIST (locally setting
+C<$_> to each element) and returns the list value consisting of those
+elements for which the expression evaluated to true. In scalar
+context, returns the number of times the expression was true.
+
+ @foo = grep(!/^#/, @bar); # weed out comments
+
+or equivalently,
+
+ @foo = grep {!/^#/} @bar; # weed out comments
+
+Note that C<$_> is an alias to the list value, so it can be used to
+modify the elements of the LIST. While this is useful and supported,
+it can cause bizarre results if the elements of LIST are not variables.
+Similarly, grep returns aliases into the original list, much as a for
+loop's index variable aliases the list elements. That is, modifying an
+element of a list returned by grep (for example, in a C<foreach>, C<map>
+or another C<grep>) actually modifies the element in the original list.
+This is usually something to be avoided when writing clear code.
+
+If C<$_> is lexical in the scope where the C<grep> appears (because it has
+been declared with C<my $_>) then, in addition to being locally aliased to
+the list elements, C<$_> keeps being lexical inside the block; i.e., it
+can't be seen from the outside, avoiding any potential side-effects.
+
+See also L</map> for a list composed of the results of the BLOCK or EXPR.
+
+=item hex EXPR
+X<hex> X<hexadecimal>
+
+=item hex
+
+Interprets EXPR as a hex string and returns the corresponding value.
+(To convert strings that might start with either C<0>, C<0x>, or C<0b>, see
+L</oct>.) If EXPR is omitted, uses C<$_>.
+
+ print hex '0xAf'; # prints '175'
+ print hex 'aF'; # same
+
+Hex strings may only represent integers. Strings that would cause
+integer overflow trigger a warning. Leading whitespace is not stripped,
+unlike oct(). To present something as hex, look into L</printf>,
+L</sprintf>, or L</unpack>.
+
+=item import LIST
+X<import>
+
+There is no builtin C<import> function. It is just an ordinary
+method (subroutine) defined (or inherited) by modules that wish to export
+names to another module. The C<use> function calls the C<import> method
+for the package used. See also L</use>, L<perlmod>, and L<Exporter>.
+
+=item index STR,SUBSTR,POSITION
+X<index> X<indexOf> X<InStr>
+
+=item index STR,SUBSTR
+
+The index function searches for one string within another, but without
+the wildcard-like behavior of a full regular-expression pattern match.
+It returns the position of the first occurrence of SUBSTR in STR at
+or after POSITION. If POSITION is omitted, starts searching from the
+beginning of the string. POSITION before the beginning of the string
+or after its end is treated as if it were the beginning or the end,
+respectively. POSITION and the return value are based at C<0> (or whatever
+you've set the C<$[> variable to--but don't do that). If the substring
+is not found, C<index> returns one less than the base, ordinarily C<-1>.
+
+=item int EXPR
+X<int> X<integer> X<truncate> X<trunc> X<floor>
+
+=item int
+
+Returns the integer portion of EXPR. If EXPR is omitted, uses C<$_>.
+You should not use this function for rounding: one because it truncates
+towards C<0>, and two because machine representations of floating-point
+numbers can sometimes produce counterintuitive results. For example,
+C<int(-6.725/0.025)> produces -268 rather than the correct -269; that's
+because it's really more like -268.99999999999994315658 instead. Usually,
+the C<sprintf>, C<printf>, or the C<POSIX::floor> and C<POSIX::ceil>
+functions will serve you better than will int().
+
+=item ioctl FILEHANDLE,FUNCTION,SCALAR
+X<ioctl>
+
+Implements the ioctl(2) function. You'll probably first have to say
+
+ require "sys/ioctl.ph"; # probably in $Config{archlib}/sys/ioctl.ph
+
+to get the correct function definitions. If F<sys/ioctl.ph> doesn't
+exist or doesn't have the correct definitions you'll have to roll your
+own, based on your C header files such as F<< <sys/ioctl.h> >>.
+(There is a Perl script called B<h2ph> that comes with the Perl kit that
+may help you in this, but it's nontrivial.) SCALAR will be read and/or
+written depending on the FUNCTION; a C pointer to the string value of SCALAR
+will be passed as the third argument of the actual C<ioctl> call. (If SCALAR
+has no string value but does have a numeric value, that value will be
+passed rather than a pointer to the string value. To guarantee this to be
+true, add a C<0> to the scalar before using it.) The C<pack> and C<unpack>
+functions may be needed to manipulate the values of structures used by
+C<ioctl>.
+
+The return value of C<ioctl> (and C<fcntl>) is as follows:
+
+ if OS returns: then Perl returns:
+ -1 undefined value
+ 0 string "0 but true"
+ anything else that number
+
+Thus Perl returns true on success and false on failure, yet you can
+still easily determine the actual value returned by the operating
+system:
+
+ $retval = ioctl(...) || -1;
+ printf "System returned %d\n", $retval;
+
+The special string C<"0 but true"> is exempt from B<-w> complaints
+about improper numeric conversions.
+
+=item join EXPR,LIST
+X<join>
+
+Joins the separate strings of LIST into a single string with fields
+separated by the value of EXPR, and returns that new string. Example:
+
+ $rec = join(':', $login,$passwd,$uid,$gid,$gcos,$home,$shell);
+
+Beware that unlike C<split>, C<join> doesn't take a pattern as its
+first argument. Compare L</split>.
+
+=item keys HASH
+X<keys> X<key>
+
+=item keys ARRAY
+
+Returns a list consisting of all the keys of the named hash, or the indices
+of an array. (In scalar context, returns the number of keys or indices.)
+
+The keys of a hash are returned in an apparently random order. The actual
+random order is subject to change in future versions of Perl, but it
+is guaranteed to be the same order as either the C<values> or C<each>
+function produces (given that the hash has not been modified). Since
+Perl 5.8.1 the ordering is different even between different runs of
+Perl for security reasons (see L<perlsec/"Algorithmic Complexity
+Attacks">).
+
+As a side effect, calling keys() resets the HASH or ARRAY's internal iterator
+(see L</each>). In particular, calling keys() in void context resets
+the iterator with no other overhead.
+
+Here is yet another way to print your environment:
+
+ @keys = keys %ENV;
+ @values = values %ENV;
+ while (@keys) {
+ print pop(@keys), '=', pop(@values), "\n";
+ }
+
+or how about sorted by key:
+
+ foreach $key (sort(keys %ENV)) {
+ print $key, '=', $ENV{$key}, "\n";
+ }
+
+The returned values are copies of the original keys in the hash, so
+modifying them will not affect the original hash. Compare L</values>.
+
+To sort a hash by value, you'll need to use a C<sort> function.
+Here's a descending numeric sort of a hash by its values:
+
+ foreach $key (sort { $hash{$b} <=> $hash{$a} } keys %hash) {
+ printf "%4d %s\n", $hash{$key}, $key;
+ }
+
+Used as an lvalue, C<keys> allows you to increase the number of hash buckets
+allocated for the given hash. This can gain you a measure of efficiency if
+you know the hash is going to get big. (This is similar to pre-extending
+an array by assigning a larger number to $#array.) If you say
+
+ keys %hash = 200;
+
+then C<%hash> will have at least 200 buckets allocated for it--256 of them,
+in fact, since it rounds up to the next power of two. These
+buckets will be retained even if you do C<%hash = ()>, use C<undef
+%hash> if you want to free the storage while C<%hash> is still in scope.
+You can't shrink the number of buckets allocated for the hash using
+C<keys> in this way (but you needn't worry about doing this by accident,
+as trying has no effect). C<keys @array> in an lvalue context is a syntax
+error.
+
+See also C<each>, C<values> and C<sort>.
+
+=item kill SIGNAL, LIST
+X<kill> X<signal>
+
+Sends a signal to a list of processes. Returns the number of
+processes successfully signaled (which is not necessarily the
+same as the number actually killed).
+
+ $cnt = kill 1, $child1, $child2;
+ kill 9, @goners;
+
+If SIGNAL is zero, no signal is sent to the process, but C<kill>
+checks whether it's I<possible> to send a signal to it (that
+means, to be brief, that the process is owned by the same user, or we are
+the super-user). This is useful to check that a child process is still
+alive (even if only as a zombie) and hasn't changed its UID. See
+L<perlport> for notes on the portability of this construct.
+
+Unlike in the shell, if SIGNAL is negative, it kills process groups instead
+of processes. That means you usually want to use positive not negative signals.
+You may also use a signal name in quotes.
+
+The behavior of kill when a I<PROCESS> number is zero or negative depends on
+the operating system. For example, on POSIX-conforming systems, zero will
+signal the current process group and -1 will signal all processes.
+
+See L<perlipc/"Signals"> for more details.
+
+=item last LABEL
+X<last> X<break>
+
+=item last
+
+The C<last> command is like the C<break> statement in C (as used in
+loops); it immediately exits the loop in question. If the LABEL is
+omitted, the command refers to the innermost enclosing loop. The
+C<continue> block, if any, is not executed:
+
+ LINE: while (<STDIN>) {
+ last LINE if /^$/; # exit when done with header
+ #...
+ }
+
+C<last> cannot be used to exit a block that returns a value such as
+C<eval {}>, C<sub {}> or C<do {}>, and should not be used to exit
+a grep() or map() operation.
+
+Note that a block by itself is semantically identical to a loop
+that executes once. Thus C<last> can be used to effect an early
+exit out of such a block.
+
+See also L</continue> for an illustration of how C<last>, C<next>, and
+C<redo> work.
+
+=item lc EXPR
+X<lc> X<lowercase>
+
+=item lc
+
+Returns a lowercased version of EXPR. This is the internal function
+implementing the C<\L> escape in double-quoted strings.
+
+If EXPR is omitted, uses C<$_>.
+
+What gets returned depends on several factors:
+
+=over
+
+=item If C<use bytes> is in effect:
+
+=over
+
+=item On EBCDIC platforms
+
+The results are what the C language system call C<tolower()> returns.
+
+=item On ASCII platforms
+
+The results follow ASCII semantics. Only characters C<A-Z> change, to C<a-z>
+respectively.
+
+=back
+
+=item Otherwise, If EXPR has the UTF8 flag set
+
+If the current package has a subroutine named C<ToLower>, it will be used to
+change the case (See L<perlunicode/User-Defined Case Mappings>.)
+Otherwise Unicode semantics are used for the case change.
+
+=item Otherwise, if C<use locale> is in effect
+
+Respects current LC_CTYPE locale. See L<perllocale>.
+
+=item Otherwise, if C<use feature 'unicode_strings'> is in effect:
+
+Unicode semantics are used for the case change. Any subroutine named
+C<ToLower> will not be used.
+
+=item Otherwise:
+
+=over
+
+=item On EBCDIC platforms
+
+The results are what the C language system call C<tolower()> returns.
+
+=item On ASCII platforms
+
+ASCII semantics are used for the case change. The lowercase of any character
+outside the ASCII range is the character itself.
+
+=back
+
+=back
+
+=item lcfirst EXPR
+X<lcfirst> X<lowercase>
+
+=item lcfirst
+
+Returns the value of EXPR with the first character lowercased. This
+is the internal function implementing the C<\l> escape in
+double-quoted strings.
+
+If EXPR is omitted, uses C<$_>.
+
+This function behaves the same way under various pragma, such as in a locale,
+as L</lc> does.
+
+=item length EXPR
+X<length> X<size>
+
+=item length
+
+Returns the length in I<characters> of the value of EXPR. If EXPR is
+omitted, returns length of C<$_>. If EXPR is undefined, returns C<undef>.
+
+This function cannot be used on an entire array or hash to find out how
+many elements these have. For that, use C<scalar @array> and C<scalar keys
+%hash>, respectively.
+
+Like all Perl character operations, length() normally deals in logical
+characters, not physical bytes. For how many bytes a string encoded as
+UTF-8 would take up, use C<length(Encode::encode_utf8(EXPR))> (you'll have
+to C<use Encode> first). See L<Encode> and L<perlunicode>.
+
+=item link OLDFILE,NEWFILE
+X<link>
+
+Creates a new filename linked to the old filename. Returns true for
+success, false otherwise.
+
+=item listen SOCKET,QUEUESIZE
+X<listen>
+
+Does the same thing that the listen(2) system call does. Returns true if
+it succeeded, false otherwise. See the example in
+L<perlipc/"Sockets: Client/Server Communication">.
+
+=item local EXPR
+X<local>
+
+You really probably want to be using C<my> instead, because C<local> isn't
+what most people think of as "local". See
+L<perlsub/"Private Variables via my()"> for details.
+
+A local modifies the listed variables to be local to the enclosing
+block, file, or eval. If more than one value is listed, the list must
+be placed in parentheses. See L<perlsub/"Temporary Values via local()">
+for details, including issues with tied arrays and hashes.
+
+The C<delete local EXPR> construct can also be used to localize the deletion
+of array/hash elements to the current block.
+See L<perlsub/"Localized deletion of elements of composite types">.
+
+=item localtime EXPR
+X<localtime> X<ctime>
+
+=item localtime
+
+Converts a time as returned by the time function to a 9-element list
+with the time analyzed for the local time zone. Typically used as
+follows:
+
+ # 0 1 2 3 4 5 6 7 8
+ ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
+ localtime(time);
+
+All list elements are numeric, and come straight out of the C `struct
+tm'. C<$sec>, C<$min>, and C<$hour> are the seconds, minutes, and hours
+of the specified time.
+
+C<$mday> is the day of the month, and C<$mon> is the month itself, in
+the range C<0..11> with 0 indicating January and 11 indicating December.
+This makes it easy to get a month name from a list:
+
+ my @abbr = qw( Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec );
+ print "$abbr[$mon] $mday";
+ # $mon=9, $mday=18 gives "Oct 18"
+
+C<$year> is the number of years since 1900, not just the last two digits
+of the year. That is, C<$year> is C<123> in year 2023. The proper way
+to get a 4-digit year is simply:
+
+ $year += 1900;
+
+Otherwise you create non-Y2K-compliant programs--and you wouldn't want
+to do that, would you?
+
+To get the last two digits of the year (e.g., '01' in 2001) do:
+
+ $year = sprintf("%02d", $year % 100);
+
+C<$wday> is the day of the week, with 0 indicating Sunday and 3 indicating
+Wednesday. C<$yday> is the day of the year, in the range C<0..364>
+(or C<0..365> in leap years.)
+
+C<$isdst> is true if the specified time occurs during Daylight Saving
+Time, false otherwise.
+
+If EXPR is omitted, C<localtime()> uses the current time (as returned
+by time(3)).
+
+In scalar context, C<localtime()> returns the ctime(3) value:
+
+ $now_string = localtime; # e.g., "Thu Oct 13 04:54:34 1994"
+
+This scalar value is B<not> locale dependent but is a Perl builtin. For GMT
+instead of local time use the L</gmtime> builtin. See also the
+C<Time::Local> module (to convert the second, minutes, hours, ... back to
+the integer value returned by time()), and the L<POSIX> module's strftime(3)
+and mktime(3) functions.
+
+To get somewhat similar but locale dependent date strings, set up your
+locale environment variables appropriately (please see L<perllocale>) and
+try for example:
+
+ use POSIX qw(strftime);
+ $now_string = strftime "%a %b %e %H:%M:%S %Y", localtime;
+ # or for GMT formatted appropriately for your locale:
+ $now_string = strftime "%a %b %e %H:%M:%S %Y", gmtime;
+
+Note that the C<%a> and C<%b>, the short forms of the day of the week
+and the month of the year, may not necessarily be three characters wide.
+
+See L<perlport/localtime> for portability concerns.
+
+The L<Time::gmtime> and L<Time::localtime> modules provides a convenient,
+by-name access mechanism to the gmtime() and localtime() functions,
+respectively.
+
+For a comprehensive date and time representation look at the
+L<DateTime> module on CPAN.
+
+=item lock THING
+X<lock>
+
+This function places an advisory lock on a shared variable, or referenced
+object contained in I<THING> until the lock goes out of scope.
+
+lock() is a "weak keyword" : this means that if you've defined a function
+by this name (before any calls to it), that function will be called
+instead. If you are not under C<use threads::shared> this does nothing.
+See L<threads::shared>.
+
+=item log EXPR
+X<log> X<logarithm> X<e> X<ln> X<base>
+
+=item log
+
+Returns the natural logarithm (base I<e>) of EXPR. If EXPR is omitted,
+returns log of C<$_>. To get the log of another base, use basic algebra:
+The base-N log of a number is equal to the natural log of that number
+divided by the natural log of N. For example:
+
+ sub log10 {
+ my $n = shift;
+ return log($n)/log(10);
+ }
+
+See also L</exp> for the inverse operation.
+
+=item lstat EXPR
+X<lstat>
+
+=item lstat
+
+Does the same thing as the C<stat> function (including setting the
+special C<_> filehandle) but stats a symbolic link instead of the file
+the symbolic link points to. If symbolic links are unimplemented on
+your system, a normal C<stat> is done. For much more detailed
+information, please see the documentation for C<stat>.
+
+If EXPR is omitted, stats C<$_>.
+
+=item m//
+
+The match operator. See L<perlop/"Regexp Quote-Like Operators">.
+
+=item map BLOCK LIST
+X<map>
+
+=item map EXPR,LIST
+
+Evaluates the BLOCK or EXPR for each element of LIST (locally setting
+C<$_> to each element) and returns the list value composed of the
+results of each such evaluation. In scalar context, returns the
+total number of elements so generated. Evaluates BLOCK or EXPR in
+list context, so each element of LIST may produce zero, one, or
+more elements in the returned value.
+
+ @chars = map(chr, @nums);
+
+translates a list of numbers to the corresponding characters. And
+
+ %hash = map { get_a_key_for($_) => $_ } @array;
+
+is just a funny way to write
+
+ %hash = ();
+ foreach (@array) {
+ $hash{get_a_key_for($_)} = $_;
+ }
+
+Note that C<$_> is an alias to the list value, so it can be used to
+modify the elements of the LIST. While this is useful and supported,
+it can cause bizarre results if the elements of LIST are not variables.
+Using a regular C<foreach> loop for this purpose would be clearer in
+most cases. See also L</grep> for an array composed of those items of
+the original list for which the BLOCK or EXPR evaluates to true.
+
+If C<$_> is lexical in the scope where the C<map> appears (because it has
+been declared with C<my $_>), then, in addition to being locally aliased to
+the list elements, C<$_> keeps being lexical inside the block; that is, it
+can't be seen from the outside, avoiding any potential side-effects.
+
+C<{> starts both hash references and blocks, so C<map { ...> could be either
+the start of map BLOCK LIST or map EXPR, LIST. Because Perl doesn't look
+ahead for the closing C<}> it has to take a guess at which it's dealing with
+based on what it finds just after the C<{>. Usually it gets it right, but if it
+doesn't it won't realize something is wrong until it gets to the C<}> and
+encounters the missing (or unexpected) comma. The syntax error will be
+reported close to the C<}>, but you'll need to change something near the C<{>
+such as using a unary C<+> to give Perl some help:
+
+ %hash = map { "\L$_" => 1 } @array # perl guesses EXPR. wrong
+ %hash = map { +"\L$_" => 1 } @array # perl guesses BLOCK. right
+ %hash = map { ("\L$_" => 1) } @array # this also works
+ %hash = map { lc($_) => 1 } @array # as does this.
+ %hash = map +( lc($_) => 1 ), @array # this is EXPR and works!
+
+ %hash = map ( lc($_), 1 ), @array # evaluates to (1, @array)
+
+or to force an anon hash constructor use C<+{>:
+
+ @hashes = map +{ lc($_) => 1 }, @array # EXPR, so needs comma at end
+
+to get a list of anonymous hashes each with only one entry apiece.
+
+=item mkdir FILENAME,MASK
+X<mkdir> X<md> X<directory, create>
+
+=item mkdir FILENAME
+
+=item mkdir
+
+Creates the directory specified by FILENAME, with permissions
+specified by MASK (as modified by C<umask>). If it succeeds it
+returns true, otherwise it returns false and sets C<$!> (errno).
+If omitted, MASK defaults to 0777. If omitted, FILENAME defaults
+to C<$_>.
+
+In general, it is better to create directories with permissive MASK,
+and let the user modify that with their C<umask>, than it is to supply
+a restrictive MASK and give the user no way to be more permissive.
+The exceptions to this rule are when the file or directory should be
+kept private (mail files, for instance). The perlfunc(1) entry on
+C<umask> discusses the choice of MASK in more detail.
+
+Note that according to the POSIX 1003.1-1996 the FILENAME may have any
+number of trailing slashes. Some operating and filesystems do not get
+this right, so Perl automatically removes all trailing slashes to keep
+everyone happy.
+
+To recursively create a directory structure, look at
+the C<mkpath> function of the L<File::Path> module.
+
+=item msgctl ID,CMD,ARG
+X<msgctl>
+
+Calls the System V IPC function msgctl(2). You'll probably have to say
+
+ use IPC::SysV;
+
+first to get the correct constant definitions. If CMD is C<IPC_STAT>,
+then ARG must be a variable that will hold the returned C<msqid_ds>
+structure. Returns like C<ioctl>: the undefined value for error,
+C<"0 but true"> for zero, or the actual return value otherwise. See also
+L<perlipc/"SysV IPC">, C<IPC::SysV>, and C<IPC::Semaphore> documentation.
+
+=item msgget KEY,FLAGS
+X<msgget>
+
+Calls the System V IPC function msgget(2). Returns the message queue
+id, or the undefined value if there is an error. See also
+L<perlipc/"SysV IPC"> and C<IPC::SysV> and C<IPC::Msg> documentation.
+
+=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
+X<msgrcv>
+
+Calls the System V IPC function msgrcv to receive a message from
+message queue ID into variable VAR with a maximum message size of
+SIZE. Note that when a message is received, the message type as a
+native long integer will be the first thing in VAR, followed by the
+actual message. This packing may be opened with C<unpack("l! a*")>.
+Taints the variable. Returns true if successful, or false if there is
+an error. See also L<perlipc/"SysV IPC">, C<IPC::SysV>, and
+C<IPC::SysV::Msg> documentation.
+
+=item msgsnd ID,MSG,FLAGS
+X<msgsnd>
+
+Calls the System V IPC function msgsnd to send the message MSG to the
+message queue ID. MSG must begin with the native long integer message
+type, and be followed by the length of the actual message, and finally
+the message itself. This kind of packing can be achieved with
+C<pack("l! a*", $type, $message)>. Returns true if successful,
+or false if there is an error. See also C<IPC::SysV>
+and C<IPC::SysV::Msg> documentation.
+
+=item my EXPR
+X<my>
+
+=item my TYPE EXPR
+
+=item my EXPR : ATTRS
+
+=item my TYPE EXPR : ATTRS
+
+A C<my> declares the listed variables to be local (lexically) to the
+enclosing block, file, or C<eval>. If more than one value is listed,
+the list must be placed in parentheses.
+
+The exact semantics and interface of TYPE and ATTRS are still
+evolving. TYPE is currently bound to the use of C<fields> pragma,
+and attributes are handled using the C<attributes> pragma, or starting
+from Perl 5.8.0 also via the C<Attribute::Handlers> module. See
+L<perlsub/"Private Variables via my()"> for details, and L<fields>,
+L<attributes>, and L<Attribute::Handlers>.
+
+=item next LABEL
+X<next> X<continue>
+
+=item next
+
+The C<next> command is like the C<continue> statement in C; it starts
+the next iteration of the loop:
+
+ LINE: while (<STDIN>) {
+ next LINE if /^#/; # discard comments
+ #...
+ }
+
+Note that if there were a C<continue> block on the above, it would get
+executed even on discarded lines. If LABEL is omitted, the command
+refers to the innermost enclosing loop.
+
+C<next> cannot be used to exit a block which returns a value such as
+C<eval {}>, C<sub {}> or C<do {}>, and should not be used to exit
+a grep() or map() operation.
+
+Note that a block by itself is semantically identical to a loop
+that executes once. Thus C<next> will exit such a block early.
+
+See also L</continue> for an illustration of how C<last>, C<next>, and
+C<redo> work.
+
+=item no MODULE VERSION LIST
+X<no declarations>
+X<unimporting>
+
+=item no MODULE VERSION
+
+=item no MODULE LIST
+
+=item no MODULE
+
+=item no VERSION
+
+See the C<use> function, of which C<no> is the opposite.
+
+=item oct EXPR
+X<oct> X<octal> X<hex> X<hexadecimal> X<binary> X<bin>
+
+=item oct
+
+Interprets EXPR as an octal string and returns the corresponding
+value. (If EXPR happens to start off with C<0x>, interprets it as a
+hex string. If EXPR starts off with C<0b>, it is interpreted as a
+binary string. Leading whitespace is ignored in all three cases.)
+The following will handle decimal, binary, octal, and hex in standard
+Perl notation:
+
+ $val = oct($val) if $val =~ /^0/;
+
+If EXPR is omitted, uses C<$_>. To go the other way (produce a number
+in octal), use sprintf() or printf():
+
+ $dec_perms = (stat("filename"))[2] & 07777;
+ $oct_perm_str = sprintf "%o", $perms;
+
+The oct() function is commonly used when a string such as C<644> needs
+to be converted into a file mode, for example. Although Perl
+automatically converts strings into numbers as needed, this automatic
+conversion assumes base 10.
+
+Leading white space is ignored without warning, as too are any trailing
+non-digits, such as a decimal point (C<oct> only handles non-negative
+integers, not negative integers or floating point).
+
+=item open FILEHANDLE,EXPR
+X<open> X<pipe> X<file, open> X<fopen>
+
+=item open FILEHANDLE,MODE,EXPR
+
+=item open FILEHANDLE,MODE,EXPR,LIST
+
+=item open FILEHANDLE,MODE,REFERENCE
+
+=item open FILEHANDLE
+
+Opens the file whose filename is given by EXPR, and associates it with
+FILEHANDLE.
+
+Simple examples to open a file for reading:
+
+ open(my $fh, '<', "input.txt") or die $!;
+
+and for writing:
+
+ open(my $fh, '>', "output.txt") or die $!;
+
+(The following is a comprehensive reference to open(): for a gentler
+introduction you may consider L<perlopentut>.)
+
+If FILEHANDLE is an undefined scalar variable (or array or hash element)
+the variable is assigned a reference to a new anonymous filehandle,
+otherwise if FILEHANDLE is an expression, its value is used as the name of
+the real filehandle wanted. (This is considered a symbolic reference, so
+C<use strict 'refs'> should I<not> be in effect.)
+
+If EXPR is omitted, the scalar variable of the same name as the
+FILEHANDLE contains the filename. (Note that lexical variables--those
+declared with C<my>--will not work for this purpose; so if you're
+using C<my>, specify EXPR in your call to open.)
+
+If three or more arguments are specified then the mode of opening and
+the filename are separate. If MODE is C<< '<' >> or nothing, the file
+is opened for input. If MODE is C<< '>' >>, the file is truncated and
+opened for output, being created if necessary. If MODE is C<<< '>>' >>>,
+the file is opened for appending, again being created if necessary.
+
+You can put a C<'+'> in front of the C<< '>' >> or C<< '<' >> to
+indicate that you want both read and write access to the file; thus
+C<< '+<' >> is almost always preferred for read/write updates--the
+C<< '+>' >> mode would clobber the file first. You can't usually use
+either read-write mode for updating textfiles, since they have
+variable length records. See the B<-i> switch in L<perlrun> for a
+better approach. The file is created with permissions of C<0666>
+modified by the process's C<umask> value.
+
+These various prefixes correspond to the fopen(3) modes of C<'r'>,
+C<'r+'>, C<'w'>, C<'w+'>, C<'a'>, and C<'a+'>.
+
+In the two-argument (and one-argument) form of the call, the mode and
+filename should be concatenated (in that order), possibly separated by
+spaces. You may omit the mode in these forms when that mode is
+C<< '<' >>.
+
+If the filename begins with C<'|'>, the filename is interpreted as a
+command to which output is to be piped, and if the filename ends with a
+C<'|'>, the filename is interpreted as a command that pipes output to
+us. See L<perlipc/"Using open() for IPC">
+for more examples of this. (You are not allowed to C<open> to a command
+that pipes both in I<and> out, but see L<IPC::Open2>, L<IPC::Open3>,
+and L<perlipc/"Bidirectional Communication with Another Process">
+for alternatives.)
+
+For three or more arguments if MODE is C<'|-'>, the filename is
+interpreted as a command to which output is to be piped, and if MODE
+is C<'-|'>, the filename is interpreted as a command that pipes
+output to us. In the two-argument (and one-argument) form, one should
+replace dash (C<'-'>) with the command.
+See L<perlipc/"Using open() for IPC"> for more examples of this.
+(You are not allowed to C<open> to a command that pipes both in I<and>
+out, but see L<IPC::Open2>, L<IPC::Open3>, and
+L<perlipc/"Bidirectional Communication"> for alternatives.)
+
+In the form of pipe opens taking three or more arguments, if LIST is specified
+(extra arguments after the command name) then LIST becomes arguments
+to the command invoked if the platform supports it. The meaning of
+C<open> with more than three arguments for non-pipe modes is not yet
+defined, but experimental "layers" may give extra LIST arguments
+meaning.
+
+In the two-argument (and one-argument) form, opening C<< '<-' >>
+or C<'-'> opens STDIN and opening C<< '>-' >> opens STDOUT.
+
+You may use the three-argument form of open to specify I/O layers
+(sometimes referred to as "disciplines") to apply to the handle
+that affect how the input and output are processed (see L<open> and
+L<PerlIO> for more details). For example:
+
+ open(my $fh, "<:encoding(UTF-8)", "filename")
+ || die "can't open UTF-8 encoded filename: $!";
+
+opens the UTF-8 encoded file containing Unicode characters;
+see L<perluniintro>. Note that if layers are specified in the
+three-argument form, then default layers stored in ${^OPEN} (see L<perlvar>;
+usually set by the B<open> pragma or the switch B<-CioD>) are ignored.
+
+Open returns nonzero on success, the undefined value otherwise. If
+the C<open> involved a pipe, the return value happens to be the pid of
+the subprocess.
+
+If you're running Perl on a system that distinguishes between text
+files and binary files, then you should check out L</binmode> for tips
+for dealing with this. The key distinction between systems that need
+C<binmode> and those that don't is their text file formats. Systems
+like Unix, Mac OS, and Plan 9, that end lines with a single
+character and encode that character in C as C<"\n"> do not
+need C<binmode>. The rest need it.
+
+When opening a file, it's seldom a good idea to continue
+if the request failed, so C<open> is frequently used with
+C<die>. Even if C<die> won't do what you want (say, in a CGI script,
+where you want to format a suitable error message (but there are
+modules that can help with that problem)) always check
+the return value from opening a file.
+
+As a special case the 3-arg form with a read/write mode and the third
+argument being C<undef>:
+
+ open(my $tmp, "+>", undef) or die ...
+
+opens a filehandle to an anonymous temporary file. Also using "+<"
+works for symmetry, but you really should consider writing something
+to the temporary file first. You will need to seek() to do the
+reading.
+
+Since v5.8.0, Perl has built using PerlIO by default. Unless you've
+changed this (i.e., Configure -Uuseperlio), you can open filehandles
+directly to Perl scalars via:
+
+ open($fh, '>', \$variable) || ..
+
+To (re)open C<STDOUT> or C<STDERR> as an in-memory file, close it first:
+
+ close STDOUT;
+ open STDOUT, '>', \$variable or die "Can't open STDOUT: $!";
+
+General examples:
+
+ $ARTICLE = 100;
+ open ARTICLE or die "Can't find article $ARTICLE: $!\n";
+ while (<ARTICLE>) {...
+
+ open(LOG, '>>/usr/spool/news/twitlog'); # (log is reserved)
+ # if the open fails, output is discarded
+
+ open(my $dbase, '+<', 'dbase.mine') # open for update
+ or die "Can't open 'dbase.mine' for update: $!";
+
+ open(my $dbase, '+<dbase.mine') # ditto
+ or die "Can't open 'dbase.mine' for update: $!";
+
+ open(ARTICLE, '-|', "caesar <$article") # decrypt article
+ or die "Can't start caesar: $!";
+
+ open(ARTICLE, "caesar <$article |") # ditto
+ or die "Can't start caesar: $!";
+
+ open(EXTRACT, "|sort >Tmp$$") # $$ is our process id
+ or die "Can't start sort: $!";
+
+ # in-memory files
+ open(MEMORY,'>', \$var)
+ or die "Can't open memory file: $!";
+ print MEMORY "foo!\n"; # output will appear in $var
+
+ # process argument list of files along with any includes
+
+ foreach $file (@ARGV) {
+ process($file, 'fh00');
+ }
+
+ sub process {
+ my($filename, $input) = @_;
+ $input++; # this is a string increment
+ unless (open($input, $filename)) {
+ print STDERR "Can't open $filename: $!\n";
+ return;
+ }
+
+ local $_;
+ while (<$input>) { # note use of indirection
+ if (/^#include "(.*)"/) {
+ process($1, $input);
+ next;
+ }
+ #... # whatever
+ }
+ }
+
+See L<perliol> for detailed info on PerlIO.
+
+You may also, in the Bourne shell tradition, specify an EXPR beginning
+with C<< '>&' >>, in which case the rest of the string is interpreted
+as the name of a filehandle (or file descriptor, if numeric) to be
+duped (as C<dup(2)>) and opened. You may use C<&> after C<< > >>,
+C<<< >> >>>, C<< < >>, C<< +> >>, C<<< +>> >>>, and C<< +< >>.
+The mode you specify should match the mode of the original filehandle.
+(Duping a filehandle does not take into account any existing contents
+of IO buffers.) If you use the 3-arg form then you can pass either a
+number, the name of a filehandle or the normal "reference to a glob".
+
+Here is a script that saves, redirects, and restores C<STDOUT> and
+C<STDERR> using various methods:
+
+ #!/usr/bin/perl
+ open my $oldout, ">&STDOUT" or die "Can't dup STDOUT: $!";
+ open OLDERR, ">&", \*STDERR or die "Can't dup STDERR: $!";
+
+ open STDOUT, '>', "foo.out" or die "Can't redirect STDOUT: $!";
+ open STDERR, ">&STDOUT" or die "Can't dup STDOUT: $!";
+
+ select STDERR; $| = 1; # make unbuffered
+ select STDOUT; $| = 1; # make unbuffered
+
+ print STDOUT "stdout 1\n"; # this works for
+ print STDERR "stderr 1\n"; # subprocesses too
+
+ open STDOUT, ">&", $oldout or die "Can't dup \$oldout: $!";
+ open STDERR, ">&OLDERR" or die "Can't dup OLDERR: $!";
+
+ print STDOUT "stdout 2\n";
+ print STDERR "stderr 2\n";
+
+If you specify C<< '<&=X' >>, where C<X> is a file descriptor number
+or a filehandle, then Perl will do an equivalent of C's C<fdopen> of
+that file descriptor (and not call C<dup(2)>); this is more
+parsimonious of file descriptors. For example:
+
+ # open for input, reusing the fileno of $fd
+ open(FILEHANDLE, "<&=$fd")
+
+or
+
+ open(FILEHANDLE, "<&=", $fd)
+
+or
+
+ # open for append, using the fileno of OLDFH
+ open(FH, ">>&=", OLDFH)
+
+or
+
+ open(FH, ">>&=OLDFH")
+
+Being parsimonious on filehandles is also useful (besides being
+parsimonious) for example when something is dependent on file
+descriptors, like for example locking using flock(). If you do just
+C<< open(A, '>>&B') >>, the filehandle A will not have the same file
+descriptor as B, and therefore flock(A) will not flock(B), and vice
+versa. But with C<< open(A, '>>&=B') >> the filehandles will share
+the same file descriptor.
+
+Note that if you are using Perls older than 5.8.0, Perl will be using
+the standard C libraries' fdopen() to implement the "=" functionality.
+On many Unix systems fdopen() fails when file descriptors exceed a
+certain value, typically 255. For Perls 5.8.0 and later, PerlIO is
+most often the default.
+
+You can see whether Perl has been compiled with PerlIO or not by
+running C<perl -V> and looking for C<useperlio=> line. If C<useperlio>
+is C<define>, you have PerlIO, otherwise you don't.
+
+If you open a pipe on the command C<'-'>, i.e., either C<'|-'> or C<'-|'>
+with 2-arguments (or 1-argument) form of open(), then
+there is an implicit fork done, and the return value of open is the pid
+of the child within the parent process, and C<0> within the child
+process. (Use C<defined($pid)> to determine whether the open was successful.)
+The filehandle behaves normally for the parent, but I/O to that
+filehandle is piped from/to the STDOUT/STDIN of the child process.
+In the child process, the filehandle isn't opened--I/O happens from/to
+the new STDOUT/STDIN. Typically this is used like the normal
+piped open when you want to exercise more control over just how the
+pipe command gets executed, such as when running setuid and
+you don't want to have to scan shell commands for metacharacters.
+
+The following triples are more or less equivalent:
+
+ open(FOO, "|tr '[a-z]' '[A-Z]'");
+ open(FOO, '|-', "tr '[a-z]' '[A-Z]'");
+ open(FOO, '|-') || exec 'tr', '[a-z]', '[A-Z]';
+ open(FOO, '|-', "tr", '[a-z]', '[A-Z]');
+
+ open(FOO, "cat -n '$file'|");
+ open(FOO, '-|', "cat -n '$file'");
+ open(FOO, '-|') || exec 'cat', '-n', $file;
+ open(FOO, '-|', "cat", '-n', $file);
+
+The last example in each block shows the pipe as "list form", which is
+not yet supported on all platforms. A good rule of thumb is that if
+your platform has true C<fork()> (in other words, if your platform is
+Unix) you can use the list form.
+
+See L<perlipc/"Safe Pipe Opens"> for more examples of this.
+
+Beginning with v5.6.0, Perl will attempt to flush all files opened for
+output before any operation that may do a fork, but this may not be
+supported on some platforms (see L<perlport>). To be safe, you may need
+to set C<$|> ($AUTOFLUSH in English) or call the C<autoflush()> method
+of C<IO::Handle> on any open handles.
+
+On systems that support a close-on-exec flag on files, the flag will
+be set for the newly opened file descriptor as determined by the value
+of $^F. See L<perlvar/$^F>.
+
+Closing any piped filehandle causes the parent process to wait for the
+child to finish, and returns the status value in C<$?> and
+C<${^CHILD_ERROR_NATIVE}>.
+
+The filename passed to 2-argument (or 1-argument) form of open() will
+have leading and trailing whitespace deleted, and the normal
+redirection characters honored. This property, known as "magic open",
+can often be used to good effect. A user could specify a filename of
+F<"rsh cat file |">, or you could change certain filenames as needed:
+
+ $filename =~ s/(.*\.gz)\s*$/gzip -dc < $1|/;
+ open(FH, $filename) or die "Can't open $filename: $!";
+
+Use 3-argument form to open a file with arbitrary weird characters in it,
+
+ open(FOO, '<', $file);
+
+otherwise it's necessary to protect any leading and trailing whitespace:
+
+ $file =~ s#^(\s)#./$1#;
+ open(FOO, "< $file\0");
+
+(this may not work on some bizarre filesystems). One should
+conscientiously choose between the I<magic> and 3-arguments form
+of open():
+
+ open IN, $ARGV[0];
+
+will allow the user to specify an argument of the form C<"rsh cat file |">,
+but will not work on a filename that happens to have a trailing space, while
+
+ open IN, '<', $ARGV[0];
+
+will have exactly the opposite restrictions.
+
+If you want a "real" C C<open> (see C<open(2)> on your system), then you
+should use the C<sysopen> function, which involves no such magic (but
+may use subtly different filemodes than Perl open(), which is mapped
+to C fopen()). This is
+another way to protect your filenames from interpretation. For example:
+
+ use IO::Handle;
+ sysopen(HANDLE, $path, O_RDWR|O_CREAT|O_EXCL)
+ or die "sysopen $path: $!";
+ $oldfh = select(HANDLE); $| = 1; select($oldfh);
+ print HANDLE "stuff $$\n";
+ seek(HANDLE, 0, 0);
+ print "File contains: ", <HANDLE>;
+
+Using the constructor from the C<IO::Handle> package (or one of its
+subclasses, such as C<IO::File> or C<IO::Socket>), you can generate anonymous
+filehandles that have the scope of whatever variables hold references to
+them, and automatically close whenever and however you leave that scope:
+
+ use IO::File;
+ #...
+ sub read_myfile_munged {
+ my $ALL = shift;
+ my $handle = IO::File->new;
+ open($handle, "myfile") or die "myfile: $!";
+ $first = <$handle>
+ or return (); # Automatically closed here.
+ mung $first or die "mung failed"; # Or here.
+ return $first, <$handle> if $ALL; # Or here.
+ $first; # Or here.
+ }
+
+See L</seek> for some details about mixing reading and writing.
+
+=item opendir DIRHANDLE,EXPR
+X<opendir>
+
+Opens a directory named EXPR for processing by C<readdir>, C<telldir>,
+C<seekdir>, C<rewinddir>, and C<closedir>. Returns true if successful.
+DIRHANDLE may be an expression whose value can be used as an indirect
+dirhandle, usually the real dirhandle name. If DIRHANDLE is an undefined
+scalar variable (or array or hash element), the variable is assigned a
+reference to a new anonymous dirhandle.
+DIRHANDLEs have their own namespace separate from FILEHANDLEs.
+
+See example at C<readdir>.
+
+=item ord EXPR
+X<ord> X<encoding>
+
+=item ord
+
+Returns the numeric (the native 8-bit encoding, like ASCII or EBCDIC,
+or Unicode) value of the first character of EXPR. If EXPR is omitted,
+uses C<$_>.
+
+For the reverse, see L</chr>.
+See L<perlunicode> for more about Unicode.
+
+=item our EXPR
+X<our> X<global>
+
+=item our TYPE EXPR
+
+=item our EXPR : ATTRS
+
+=item our TYPE EXPR : ATTRS
+
+C<our> associates a simple name with a package variable in the current
+package for use within the current scope. When C<use strict 'vars'> is in
+effect, C<our> lets you use declared global variables without qualifying
+them with package names, within the lexical scope of the C<our> declaration.
+In this way C<our> differs from C<use vars>, which is package scoped.
+
+Unlike C<my>, which both allocates storage for a variable and associates
+a simple name with that storage for use within the current scope, C<our>
+associates a simple name with a package variable in the current package,
+for use within the current scope. In other words, C<our> has the same
+scoping rules as C<my>, but does not necessarily create a
+variable.
+
+If more than one value is listed, the list must be placed
+in parentheses.
+
+ our $foo;
+ our($bar, $baz);
+
+An C<our> declaration declares a global variable that will be visible
+across its entire lexical scope, even across package boundaries. The
+package in which the variable is entered is determined at the point
+of the declaration, not at the point of use. This means the following
+behavior holds:
+
+ package Foo;
+ our $bar; # declares $Foo::bar for rest of lexical scope
+ $bar = 20;
+
+ package Bar;
+ print $bar; # prints 20, as it refers to $Foo::bar
+
+Multiple C<our> declarations with the same name in the same lexical
+scope are allowed if they are in different packages. If they happen
+to be in the same package, Perl will emit warnings if you have asked
+for them, just like multiple C<my> declarations. Unlike a second
+C<my> declaration, which will bind the name to a fresh variable, a
+second C<our> declaration in the same package, in the same scope, is
+merely redundant.
+
+ use warnings;
+ package Foo;
+ our $bar; # declares $Foo::bar for rest of lexical scope
+ $bar = 20;
+
+ package Bar;
+ our $bar = 30; # declares $Bar::bar for rest of lexical scope
+ print $bar; # prints 30
+
+ our $bar; # emits warning but has no other effect
+ print $bar; # still prints 30
+
+An C<our> declaration may also have a list of attributes associated
+with it.
+
+The exact semantics and interface of TYPE and ATTRS are still
+evolving. TYPE is currently bound to the use of C<fields> pragma,
+and attributes are handled using the C<attributes> pragma, or starting
+from Perl 5.8.0 also via the C<Attribute::Handlers> module. See
+L<perlsub/"Private Variables via my()"> for details, and L<fields>,
+L<attributes>, and L<Attribute::Handlers>.
+
+=item pack TEMPLATE,LIST
+X<pack>
+
+Takes a LIST of values and converts it into a string using the rules
+given by the TEMPLATE. The resulting string is the concatenation of
+the converted values. Typically, each converted value looks
+like its machine-level representation. For example, on 32-bit machines
+an integer may be represented by a sequence of 4 bytes, which will in
+Perl be presented as a string that's 4 characters long.
+
+See L<perlpacktut> for an introduction to this function.
+
+The TEMPLATE is a sequence of characters that give the order and type
+of values, as follows:
+
+ a A string with arbitrary binary data, will be null padded.
+ A A text (ASCII) string, will be space padded.
+ Z A null-terminated (ASCIZ) string, will be null padded.
+
+ b A bit string (ascending bit order inside each byte, like vec()).
+ B A bit string (descending bit order inside each byte).
+ h A hex string (low nybble first).
+ H A hex string (high nybble first).
+
+ c A signed char (8-bit) value.
+ C An unsigned char (octet) value.
+ W An unsigned char value (can be greater than 255).
+
+ s A signed short (16-bit) value.
+ S An unsigned short value.
+
+ l A signed long (32-bit) value.
+ L An unsigned long value.
+
+ q A signed quad (64-bit) value.
+ Q An unsigned quad value.
+ (Quads are available only if your system supports 64-bit
+ integer values _and_ if Perl has been compiled to support those.
+ Raises an exception otherwise.)
+
+ i A signed integer value.
+ I A unsigned integer value.
+ (This 'integer' is _at_least_ 32 bits wide. Its exact
+ size depends on what a local C compiler calls 'int'.)
+
+ n An unsigned short (16-bit) in "network" (big-endian) order.
+ N An unsigned long (32-bit) in "network" (big-endian) order.
+ v An unsigned short (16-bit) in "VAX" (little-endian) order.
+ V An unsigned long (32-bit) in "VAX" (little-endian) order.
+
+ j A Perl internal signed integer value (IV).
+ J A Perl internal unsigned integer value (UV).
+
+ f A single-precision float in native format.
+ d A double-precision float in native format.
+
+ F A Perl internal floating-point value (NV) in native format
+ D A float of long-double precision in native format.
+ (Long doubles are available only if your system supports long
+ double values _and_ if Perl has been compiled to support those.
+ Raises an exception otherwise.)
+
+ p A pointer to a null-terminated string.
+ P A pointer to a structure (fixed-length string).
+
+ u A uuencoded string.
+ U A Unicode character number. Encodes to a character in character mode
+ and UTF-8 (or UTF-EBCDIC in EBCDIC platforms) in byte mode.
+
+ w A BER compressed integer (not an ASN.1 BER, see perlpacktut for
+ details). Its bytes represent an unsigned integer in base 128,
+ most significant digit first, with as few digits as possible. Bit
+ eight (the high bit) is set on each byte except the last.
+
+ x A null byte (a.k.a ASCII NUL, "\000", chr(0))
+ X Back up a byte.
+ @ Null-fill or truncate to absolute position, counted from the
+ start of the innermost ()-group.
+ . Null-fill or truncate to absolute position specified by the value.
+ ( Start of a ()-group.
+
+One or more modifiers below may optionally follow certain letters in the
+TEMPLATE (the second column lists letters for which the modifier is valid):
+
+ ! sSlLiI Forces native (short, long, int) sizes instead
+ of fixed (16-/32-bit) sizes.
+
+ xX Make x and X act as alignment commands.
+
+ nNvV Treat integers as signed instead of unsigned.
+
+ @. Specify position as byte offset in the internal
+ representation of the packed string. Efficient but
+ dangerous.
+
+ > sSiIlLqQ Force big-endian byte-order on the type.
+ jJfFdDpP (The "big end" touches the construct.)
+
+ < sSiIlLqQ Force little-endian byte-order on the type.
+ jJfFdDpP (The "little end" touches the construct.)
+
+The C<< > >> and C<< < >> modifiers can also be used on C<()> groups
+to force a particular byte-order on all components in that group,
+including all its subgroups.
+
+The following rules apply:
+
+=over
+
+=item *
+
+Each letter may optionally be followed by a number indicating the repeat
+count. A numeric repeat count may optionally be enclosed in brackets, as
+in C<pack("C[80]", @arr)>. The repeat count gobbles that many values from
+the LIST when used with all format types other than C<a>, C<A>, C<Z>, C<b>,
+C<B>, C<h>, C<H>, C<@>, C<.>, C<x>, C<X>, and C<P>, where it means
+something else, dscribed below. Supplying a C<*> for the repeat count
+instead of a number means to use however many items are left, except for:
+
+=over
+
+=item *
+
+C<@>, C<x>, and C<X>, where it is equivalent to C<0>.
+
+=item *
+
+<.>, where it means relative to the start of the string.
+
+=item *
+
+C<u>, where it is equivalent to 1 (or 45, which here is equivalent).
+
+=back
+
+One can replace a numeric repeat count with a template letter enclosed in
+brackets to use the packed byte length of the bracketed template for the
+repeat count.
+
+For example, the template C<x[L]> skips as many bytes as in a packed long,
+and the template C<"$t X[$t] $t"> unpacks twice whatever $t (when
+variable-expanded) unpacks. If the template in brackets contains alignment
+commands (such as C<x![d]>), its packed length is calculated as if the
+start of the template had the maximal possible alignment.
+
+When used with C<Z>, a C<*> as the repeat count is guaranteed to add a
+trailing null byte, so the resulting string is always one byte longer than
+the byte length of the item itself.
+
+When used with C<@>, the repeat count represents an offset from the start
+of the innermost C<()> group.
+
+When used with C<.>, the repeat count determines the starting position to
+calculate the value offset as follows:
+
+=over
+
+=item *
+
+If the repeat count is C<0>, it's relative to the current position.
+
+=item *
+
+If the repeat count is C<*>, the offset is relative to the start of the
+packed string.
+
+=item *
+
+And if it's an integer I<n>, the offset is relative to the start of the
+I<n>th innermost C<()> group, or to the start of the string if I<n> is
+bigger then the group level.
+
+=back
+
+The repeat count for C<u> is interpreted as the maximal number of bytes
+to encode per line of output, with 0, 1 and 2 replaced by 45. The repeat
+count should not be more than 65.
+
+=item *
+
+The C<a>, C<A>, and C<Z> types gobble just one value, but pack it as a
+string of length count, padding with nulls or spaces as needed. When
+unpacking, C<A> strips trailing whitespace and nulls, C<Z> strips everything
+after the first null, and C<a> returns data without any sort of trimming.
+
+If the value to pack is too long, the result is truncated. If it's too
+long and an explicit count is provided, C<Z> packs only C<$count-1> bytes,
+followed by a null byte. Thus C<Z> always packs a trailing null, except
+for when the count is 0.
+
+=item *
+
+Likewise, the C<b> and C<B> formats pack a string that's that many bits long.
+Each such format generates 1 bit of the result.
+
+Each result bit is based on the least-significant bit of the corresponding
+input character, i.e., on C<ord($char)%2>. In particular, characters C<"0">
+and C<"1"> generate bits 0 and 1, as do characters C<"\000"> and C<"\001">.
+
+Starting from the beginning of the input string, each 8-tuple
+of characters is converted to 1 character of output. With format C<b>,
+the first character of the 8-tuple determines the least-significant bit of a
+character; with format C<B>, it determines the most-significant bit of
+a character.
+
+If the length of the input string is not evenly divisible by 8, the
+remainder is packed as if the input string were padded by null characters
+at the end. Similarly during unpacking, "extra" bits are ignored.
+
+If the input string is longer than needed, remaining characters are ignored.
+
+A C<*> for the repeat count uses all characters of the input field.
+On unpacking, bits are converted to a string of C<"0">s and C<"1">s.
+
+=item *
+
+The C<h> and C<H> formats pack a string that many nybbles (4-bit groups,
+representable as hexadecimal digits, C<"0".."9"> C<"a".."f">) long.
+
+For each such format, pack() generates 4 bits of the result.
+With non-alphabetical characters, the result is based on the 4 least-significant
+bits of the input character, i.e., on C<ord($char)%16>. In particular,
+characters C<"0"> and C<"1"> generate nybbles 0 and 1, as do bytes
+C<"\0"> and C<"\1">. For characters C<"a".."f"> and C<"A".."F">, the result
+is compatible with the usual hexadecimal digits, so that C<"a"> and
+C<"A"> both generate the nybble C<0xa==10>. Do not use any characters
+but these with this format.
+
+Starting from the beginning of the template to pack(), each pair
+of characters is converted to 1 character of output. With format C<h>, the
+first character of the pair determines the least-significant nybble of the
+output character; with format C<H>, it determines the most-significant
+nybble.
+
+If the length of the input string is not even, it behaves as if padded by
+a null character at the end. Similarly, "extra" nybbles are ignored during
+unpacking.
+
+If the input string is longer than needed, extra characters are ignored.
+
+A C<*> for the repeat count uses all characters of the input field. For
+unpack(), nybbles are converted to a string of hexadecimal digits.
+
+=item *
+
+The C<p> format packs a pointer to a null-terminated string. You are
+responsible for ensuring that the string is not a temporary value, as that
+could potentially get deallocated before you got around to using the packed
+result. The C<P> format packs a pointer to a structure of the size indicated
+by the length. A null pointer is created if the corresponding value for
+C<p> or C<P> is C<undef>; similarly with unpack(), where a null pointer
+unpacks into C<undef>.
+
+If your system has a strange pointer size--meaning a pointer is neither as
+big as an int nor as big as a long--it may not be possible to pack or
+unpack pointers in big- or little-endian byte order. Attempting to do
+so raises an exception.
+
+=item *
+
+The C</> template character allows packing and unpacking of a sequence of
+items where the packed structure contains a packed item count followed by
+the packed items themselves. This is useful when the structure you're
+unpacking has encoded the sizes or repeat counts for some of its fields
+within the structure itself as separate fields.
+
+For C<pack>, you write I<length-item>C</>I<sequence-item>, and the
+I<length-item> describes how the length value is packed. Formats likely
+to be of most use are integer-packing ones like C<n> for Java strings,
+C<w> for ASN.1 or SNMP, and C<N> for Sun XDR.
+
+For C<pack>, I<sequence-item> may have a repeat count, in which case
+the minimum of that and the number of available items is used as the argument
+for I<length-item>. If it has no repeat count or uses a '*', the number
+of available items is used.
+
+For C<unpack>, an internal stack of integer arguments unpacked so far is
+used. You write C</>I<sequence-item> and the repeat count is obtained by
+popping off the last element from the stack. The I<sequence-item> must not
+have a repeat count.
+
+If I<sequence-item> refers to a string type (C<"A">, C<"a">, or C<"Z">),
+the I<length-item> is the string length, not the number of strings. With
+an explicit repeat count for pack, the packed string is adjusted to that
+length. For example:
+
+ unpack("W/a", "\04Gurusamy") gives ("Guru")
+ unpack("a3/A A*", "007 Bond J ") gives (" Bond", "J")
+ unpack("a3 x2 /A A*", "007: Bond, J.") gives ("Bond, J", ".")
+
+ pack("n/a* w/a","hello,","world") gives "\000\006hello,\005world"
+ pack("a/W2", ord("a") .. ord("z")) gives "2ab"
+
+The I<length-item> is not returned explicitly from C<unpack>.
+
+Supplying a count to the I<length-item> format letter is only useful with
+C<A>, C<a>, or C<Z>. Packing with a I<length-item> of C<a> or C<Z> may
+introduce C<"\000"> characters, which Perl does not regard as legal in
+numeric strings.
+
+=item *
+
+The integer types C<s>, C<S>, C<l>, and C<L> may be
+followed by a C<!> modifier to specify native shorts or
+longs. As shown in the example above, a bare C<l> means
+exactly 32 bits, although the native C<long> as seen by the local C compiler
+may be larger. This is mainly an issue on 64-bit platforms. You can
+see whether using C<!> makes any difference this way:
+
+ printf "format s is %d, s! is %d\n",
+ length pack("s"), length pack("s!");
+
+ printf "format l is %d, l! is %d\n",
+ length pack("l"), length pack("l!");
+
+
+C<i!> and C<I!> are also allowed, but only for completeness' sake:
+they are identical to C<i> and C<I>.
+
+The actual sizes (in bytes) of native shorts, ints, longs, and long
+longs on the platform where Perl was built are also available from
+the command line:
+
+ $ perl -V:{short,int,long{,long}}size
+ shortsize='2';
+ intsize='4';
+ longsize='4';
+ longlongsize='8';
+
+or programmatically via the C<Config> module:
+
+ use Config;
+ print $Config{shortsize}, "\n";
+ print $Config{intsize}, "\n";
+ print $Config{longsize}, "\n";
+ print $Config{longlongsize}, "\n";
+
+C<$Config{longlongsize}> is undefined on systems without
+long long support.
+
+=item *
+
+The integer formats C<s>, C<S>, C<i>, C<I>, C<l>, C<L>, C<j>, and C<J> are
+inherently non-portable between processors and operating systems because
+they obey native byteorder and endianness. For example, a 4-byte integer
+0x12345678 (305419896 decimal) would be ordered natively (arranged in and
+handled by the CPU registers) into bytes as
+
+ 0x12 0x34 0x56 0x78 # big-endian
+ 0x78 0x56 0x34 0x12 # little-endian
+
+Basically, Intel and VAX CPUs are little-endian, while everybody else,
+including Motorola m68k/88k, PPC, Sparc, HP PA, Power, and Cray, are
+big-endian. Alpha and MIPS can be either: Digital/Compaq used/uses them in
+little-endian mode, but SGI/Cray uses them in big-endian mode.
+
+The names I<big-endian> and I<little-endian> are comic references to the
+egg-eating habits of the little-endian Lilliputians and the big-endian
+Blefuscudians from the classic Jonathan Swift satire, I<Gulliver's Travels>.
+This entered computer lingo via the paper "On Holy Wars and a Plea for
+Peace" by Danny Cohen, USC/ISI IEN 137, April 1, 1980.
+
+Some systems may have even weirder byte orders such as
+
+ 0x56 0x78 0x12 0x34
+ 0x34 0x12 0x78 0x56
+
+You can determine your system endianness with this incantation:
+
+ printf("%#02x ", $_) for unpack("W*", pack L=>0x12345678);
+
+The byteorder on the platform where Perl was built is also available
+via L<Config>:
+
+ use Config;
+ print "$Config{byteorder}\n";
+
+or from the command line:
+
+ $ perl -V:byteorder
+
+Byteorders C<"1234"> and C<"12345678"> are little-endian; C<"4321">
+and C<"87654321"> are big-endian.
+
+For portably packed integers, either use the formats C<n>, C<N>, C<v>,
+and C<V> or else use the C<< > >> and C<< < >> modifiers described
+immediately below. See also L<perlport>.
+
+=item *
+
+Starting with Perl 5.9.2, integer and floating-point formats, along with
+the C<p> and C<P> formats and C<()> groups, may all be followed by the
+C<< > >> or C<< < >> endianness modifiers to respectively enforce big-
+or little-endian byte-order. These modifiers are especially useful
+given how C<n>, C<N>, C<v> and C<V> don't cover signed integers,
+64-bit integers, or floating-point values.
+
+Here are some concerns to keep in mind when using endianness modifier:
+
+=over
+
+=item *
+
+Exchanging signed integers between different platforms works only
+when all platforms store them in the same format. Most platforms store
+signed integers in two's-complement notation, so usually this is not an issue.
+
+=item *
+
+The C<< > >> or C<< < >> modifiers can only be used on floating-point
+formats on big- or little-endian machines. Otherwise, attempting to
+use them raises an exception.
+
+=item *
+
+Forcing big- or little-endian byte-order on floating-point values for
+data exchange can work only if all platforms use the same
+binary representation such as IEEE floating-point. Even if all
+platforms are using IEEE, there may still be subtle differences. Being able
+to use C<< > >> or C<< < >> on floating-point values can be useful,
+but also dangerous if you don't know exactly what you're doing.
+It is not a general way to portably store floating-point values.
+
+=item *
+
+When using C<< > >> or C<< < >> on a C<()> group, this affects
+all types inside the group that accept byte-order modifiers,
+including all subgroups. It is silently ignored for all other
+types. You are not allowed to override the byte-order within a group
+that already has a byte-order modifier suffix.
+
+=back
+
+=item *
+
+Real numbers (floats and doubles) are in native machine format only.
+Due to the multiplicity of floating-point formats and the lack of a
+standard "network" representation for them, no facility for interchange has been
+made. This means that packed floating-point data written on one machine
+may not be readable on another, even if both use IEEE floating-point
+arithmetic (because the endianness of the memory representation is not part
+of the IEEE spec). See also L<perlport>.
+
+If you know I<exactly> what you're doing, you can use the C<< > >> or C<< < >>
+modifiers to force big- or little-endian byte-order on floating-point values.
+
+Because Perl uses doubles (or long doubles, if configured) internally for
+all numeric calculation, converting from double into float and thence
+to double again loses precision, so C<unpack("f", pack("f", $foo)>)
+will not in general equal $foo.
+
+=item *
+
+Pack and unpack can operate in two modes: character mode (C<C0> mode) where
+the packed string is processed per character, and UTF-8 mode (C<U0> mode)
+where the packed string is processed in its UTF-8-encoded Unicode form on
+a byte-by-byte basis. Character mode is the default unless the format string
+starts with C<U>. You can always switch mode mid-format with an explicit
+C<C0> or C<U0> in the format. This mode remains in effect until the next
+mode change, or until the end of the C<()> group it (directly) applies to.
+
+=item *
+
+You must yourself do any alignment or padding by inserting, for example,
+enough C<"x">es while packing. There is no way for pack() and unpack()
+to know where characters are going to or coming from, so they
+handle their output and input as flat sequences of characters.
+
+=item *
+
+A C<()> group is a sub-TEMPLATE enclosed in parentheses. A group may
+take a repeat count either as postfix, or for unpack(), also via the C</>
+template character. Within each repetition of a group, positioning with
+C<@> starts over at 0. Therefore, the result of
+
+ pack("@1A((@2A)@3A)", qw[X Y Z])
+
+is the string C<"\0X\0\0YZ">.
+
+=item *
+
+C<x> and C<X> accept the C<!> modifier to act as alignment commands: they
+jump forward or back to the closest position aligned at a multiple of C<count>
+characters. For example, to pack() or unpack() a C structure like
+
+ struct {
+ char c; /* one signed, 8-bit character */
+ double d;
+ char cc[2];
+ }
+
+one may need to use the template C<c x![d] d c[2]>. This assumes that
+doubles must be aligned to the size of double.
+
+For alignment commands, a C<count> of 0 is equivalent to a C<count> of 1;
+both are no-ops.
+
+=item *
+
+C<n>, C<N>, C<v> and C<V> accept the C<!> modifier to
+represent signed 16-/32-bit integers in big-/little-endian order.
+This is portable only when all platforms sharing packed data use the
+same binary representation for signed integers; for example, when all
+platforms use two's-complement representation.
+
+=item *
+
+Comments can be embedded in a TEMPLATE using C<#> through the end of line.
+White space can separate pack codes from each other, but modifiers and
+repeat counts must follow immediately. Breaking complex templates into
+individual line-by-line components, suitably annotated, can do as much to
+improve legibility and maintainability of pack/unpack formats as C</x> can
+for complicated pattern matches.
+
+=item *
+
+If TEMPLATE requires more arguments that pack() is given, pack()
+assumes additional C<""> arguments. If TEMPLATE requires fewer arguments
+than given, extra arguments are ignored.
+
+=back
+
+Examples:
+
+ $foo = pack("WWWW",65,66,67,68);
+ # foo eq "ABCD"
+ $foo = pack("W4",65,66,67,68);
+ # same thing
+ $foo = pack("W4",0x24b6,0x24b7,0x24b8,0x24b9);
+ # same thing with Unicode circled letters.
+ $foo = pack("U4",0x24b6,0x24b7,0x24b8,0x24b9);
+ # same thing with Unicode circled letters. You don't get the UTF-8
+ # bytes because the U at the start of the format caused a switch to
+ # U0-mode, so the UTF-8 bytes get joined into characters
+ $foo = pack("C0U4",0x24b6,0x24b7,0x24b8,0x24b9);
+ # foo eq "\xe2\x92\xb6\xe2\x92\xb7\xe2\x92\xb8\xe2\x92\xb9"
+ # This is the UTF-8 encoding of the string in the previous example
+
+ $foo = pack("ccxxcc",65,66,67,68);
+ # foo eq "AB\0\0CD"
+
+ # NOTE: The examples above featuring "W" and "c" are true
+ # only on ASCII and ASCII-derived systems such as ISO Latin 1
+ # and UTF-8. On EBCDIC systems, the first example would be
+ # $foo = pack("WWWW",193,194,195,196);
+
+ $foo = pack("s2",1,2);
+ # "\1\0\2\0" on little-endian
+ # "\0\1\0\2" on big-endian
+
+ $foo = pack("a4","abcd","x","y","z");
+ # "abcd"
+
+ $foo = pack("aaaa","abcd","x","y","z");
+ # "axyz"
+
+ $foo = pack("a14","abcdefg");
+ # "abcdefg\0\0\0\0\0\0\0"
+
+ $foo = pack("i9pl", gmtime);
+ # a real struct tm (on my system anyway)
+
+ $utmp_template = "Z8 Z8 Z16 L";
+ $utmp = pack($utmp_template, @utmp1);
+ # a struct utmp (BSDish)
+
+ @utmp2 = unpack($utmp_template, $utmp);
+ # "@utmp1" eq "@utmp2"
+
+ sub bintodec {
+ unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
+ }
+
+ $foo = pack('sx2l', 12, 34);
+ # short 12, two zero bytes padding, long 34
+ $bar = pack('s@4l', 12, 34);
+ # short 12, zero fill to position 4, long 34
+ # $foo eq $bar
+ $baz = pack('s.l', 12, 4, 34);
+ # short 12, zero fill to position 4, long 34
+
+ $foo = pack('nN', 42, 4711);
+ # pack big-endian 16- and 32-bit unsigned integers
+ $foo = pack('S>L>', 42, 4711);
+ # exactly the same
+ $foo = pack('s<l<', -42, 4711);
+ # pack little-endian 16- and 32-bit signed integers
+ $foo = pack('(sl)<', -42, 4711);
+ # exactly the same
+
+The same template may generally also be used in unpack().
+
+=item package NAMESPACE VERSION
+X<package> X<module> X<namespace> X<version>
+
+=item package NAMESPACE
+
+Declares the compilation unit as being in the given namespace. The scope
+of the package declaration is from the declaration itself through the end
+of the enclosing block, file, or eval (the same as the C<my> operator).
+All further unqualified dynamic identifiers will be in this namespace.
+A package statement affects dynamic variables only, including those
+you've used C<local> on, but I<not> lexical variables, which are created
+with C<my> (or C<our> (or C<state>)). Typically it would be the first
+declaration in a file included by C<require> or C<use>. You can switch into a
+package in more than one place, since this only determines which default
+symbol table the compiler uses for the rest of that block. You can refer to
+identifiers in other packages than the current one by prefixing the identifier
+with the package name and a double colon, as in C<$SomePack::var>
+or C<ThatPack::INPUT_HANDLE>. If package name is omitted, the C<main>
+package as assumed. That is, C<$::sail> is equivalent to
+C<$main::sail> (as well as to C<$main'sail>, still seen in ancient
+code, mostly from Perl 4).
+
+If VERSION is provided, C<package> sets the C<$VERSION> variable in the given
+namespace to a L<version> object with the VERSION provided. VERSION must be a
+"strict" style version number as defined by the L<version> module: a positive
+decimal number (integer or decimal-fraction) without exponentiation or else a
+dotted-decimal v-string with a leading 'v' character and at least three
+components. You should set C<$VERSION> only once per package.
+
+See L<perlmod/"Packages"> for more information about packages, modules,
+and classes. See L<perlsub> for other scoping issues.
+
+=item pipe READHANDLE,WRITEHANDLE
+X<pipe>
+
+Opens a pair of connected pipes like the corresponding system call.
+Note that if you set up a loop of piped processes, deadlock can occur
+unless you are very careful. In addition, note that Perl's pipes use
+IO buffering, so you may need to set C<$|> to flush your WRITEHANDLE
+after each command, depending on the application.
+
+See L<IPC::Open2>, L<IPC::Open3>, and L<perlipc/"Bidirectional Communication">
+for examples of such things.
+
+On systems that support a close-on-exec flag on files, that flag is set
+on all newly opened file descriptors whose C<fileno>s are I<higher> than
+the current value of $^F (by default 2 for C<STDERR>). See L<perlvar/$^F>.
+
+=item pop ARRAY
+X<pop> X<stack>
+
+=item pop
+
+Pops and returns the last value of the array, shortening the array by
+one element.
+
+Returns the undefined value if the array is empty, although this may also
+happen at other times. If ARRAY is omitted, pops the C<@ARGV> array in the
+main program, but the C<@_> array in subroutines, just like C<shift>.
+
+=item pos SCALAR
+X<pos> X<match, position>
+
+=item pos
+
+Returns the offset of where the last C<m//g> search left off for the variable
+in question (C<$_> is used when the variable is not specified). Note that
+0 is a valid match offset. C<undef> indicates that the search position
+is reset (usually due to match failure, but can also be because no match has
+yet been run on the scalar). C<pos> directly accesses the location used
+by the regexp engine to store the offset, so assigning to C<pos> will change
+that offset, and so will also influence the C<\G> zero-width assertion in
+regular expressions. Because a failed C<m//gc> match doesn't reset the offset,
+the return from C<pos> won't change either in this case. See L<perlre> and
+L<perlop>.
+
+=item print FILEHANDLE LIST
+X<print>
+
+=item print LIST
+
+=item print
+
+Prints a string or a list of strings. Returns true if successful.
+FILEHANDLE may be a scalar variable containing
+the name of or a reference to the filehandle, thus introducing
+one level of indirection. (NOTE: If FILEHANDLE is a variable and
+the next token is a term, it may be misinterpreted as an operator
+unless you interpose a C<+> or put parentheses around the arguments.)
+If FILEHANDLE is omitted, prints to standard output by default, or
+to the last selected output channel; see L</select>. If LIST is
+also omitted, prints C<$_> to the currently selected output handle.
+To set the default output handle to something other than STDOUT
+use the select operation. The current value of C<$,> (if any) is
+printed between each LIST item. The current value of C<$\> (if
+any) is printed after the entire LIST has been printed. Because
+print takes a LIST, anything in the LIST is evaluated in list
+context, and any subroutine that you call will have one or more of
+its expressions evaluated in list context. Also be careful not to
+follow the print keyword with a left parenthesis unless you want
+the corresponding right parenthesis to terminate the arguments to
+the print; put parentheses around all the arguments
+(or interpose a C<+>, but that doesn't look as good).
+
+Note that if you're storing FILEHANDLEs in an array, or if you're using
+any other expression more complex than a scalar variable to retrieve it,
+you will have to use a block returning the filehandle value instead:
+
+ print { $files[$i] } "stuff\n";
+ print { $OK ? STDOUT : STDERR } "stuff\n";
+
+Printing to a closed pipe or socket will generate a SIGPIPE signal. See
+L<perlipc> for more on signal handling.
+
+=item printf FILEHANDLE FORMAT, LIST
+X<printf>
+
+=item printf FORMAT, LIST
+
+Equivalent to C<print FILEHANDLE sprintf(FORMAT, LIST)>, except that C<$\>
+(the output record separator) is not appended. The first argument
+of the list will be interpreted as the C<printf> format. See C<sprintf>
+for an explanation of the format argument. If C<use locale> is in effect,
+and POSIX::setlocale() has been called, the character used for the decimal
+separator in formatted floating-point numbers is affected by the LC_NUMERIC
+locale. See L<perllocale> and L<POSIX>.
+
+Don't fall into the trap of using a C<printf> when a simple
+C<print> would do. The C<print> is more efficient and less
+error prone.
+
+=item prototype FUNCTION
+X<prototype>
+
+Returns the prototype of a function as a string (or C<undef> if the
+function has no prototype). FUNCTION is a reference to, or the name of,
+the function whose prototype you want to retrieve.
+
+If FUNCTION is a string starting with C<CORE::>, the rest is taken as a
+name for a Perl builtin. If the builtin is not I<overridable> (such as
+C<qw//>) or if its arguments cannot be adequately expressed by a prototype
+(such as C<system>), prototype() returns C<undef>, because the builtin
+does not really behave like a Perl function. Otherwise, the string
+describing the equivalent prototype is returned.
+
+=item push ARRAY,LIST
+X<push> X<stack>
+
+Treats ARRAY as a stack, and pushes the values of LIST
+onto the end of ARRAY. The length of ARRAY increases by the length of
+LIST. Has the same effect as
+
+ for $value (LIST) {
+ $ARRAY[++$#ARRAY] = $value;
+ }
+
+but is more efficient. Returns the number of elements in the array following
+the completed C<push>.
+
+=item q/STRING/
+
+=item qq/STRING/
+
+=item qx/STRING/
+
+=item qw/STRING/
+
+Generalized quotes. See L<perlop/"Quote-Like Operators">.
+
+=item qr/STRING/
+
+Regexp-like quote. See L<perlop/"Regexp Quote-Like Operators">.
+
+=item quotemeta EXPR
+X<quotemeta> X<metacharacter>
+
+=item quotemeta
+
+Returns the value of EXPR with all non-"word"
+characters backslashed. (That is, all characters not matching
+C</[A-Za-z_0-9]/> will be preceded by a backslash in the
+returned string, regardless of any locale settings.)
+This is the internal function implementing
+the C<\Q> escape in double-quoted strings.
+
+If EXPR is omitted, uses C<$_>.
+
+quotemeta (and C<\Q> ... C<\E>) are useful when interpolating strings into
+regular expressions, because by default an interpolated variable will be
+considered a mini-regular expression. For example:
+
+ my $sentence = 'The quick brown fox jumped over the lazy dog';
+ my $substring = 'quick.*?fox';
+ $sentence =~ s{$substring}{big bad wolf};
+
+Will cause C<$sentence> to become C<'The big bad wolf jumped over...'>.
+
+On the other hand:
+
+ my $sentence = 'The quick brown fox jumped over the lazy dog';
+ my $substring = 'quick.*?fox';
+ $sentence =~ s{\Q$substring\E}{big bad wolf};
+
+Or:
+
+ my $sentence = 'The quick brown fox jumped over the lazy dog';
+ my $substring = 'quick.*?fox';
+ my $quoted_substring = quotemeta($substring);
+ $sentence =~ s{$quoted_substring}{big bad wolf};
+
+Will both leave the sentence as is. Normally, when accepting string input from
+the user, quotemeta() or C<\Q> must be used.
+
+=item rand EXPR
+X<rand> X<random>
+
+=item rand
+
+Returns a random fractional number greater than or equal to C<0> and less
+than the value of EXPR. (EXPR should be positive.) If EXPR is
+omitted, the value C<1> is used. Currently EXPR with the value C<0> is
+also special-cased as C<1> (this was undocumented before Perl 5.8.0
+and is subject to change in future versions of Perl). Automatically calls
+C<srand> unless C<srand> has already been called. See also C<srand>.
+
+Apply C<int()> to the value returned by C<rand()> if you want random
+integers instead of random fractional numbers. For example,
+
+ int(rand(10))
+
+returns a random integer between C<0> and C<9>, inclusive.
+
+(Note: If your rand function consistently returns numbers that are too
+large or too small, then your version of Perl was probably compiled
+with the wrong number of RANDBITS.)
+
+=item read FILEHANDLE,SCALAR,LENGTH,OFFSET
+X<read> X<file, read>
+
+=item read FILEHANDLE,SCALAR,LENGTH
+
+Attempts to read LENGTH I<characters> of data into variable SCALAR
+from the specified FILEHANDLE. Returns the number of characters
+actually read, C<0> at end of file, or undef if there was an error (in
+the latter case C<$!> is also set). SCALAR will be grown or shrunk
+so that the last character actually read is the last character of the
+scalar after the read.
+
+An OFFSET may be specified to place the read data at some place in the
+string other than the beginning. A negative OFFSET specifies
+placement at that many characters counting backwards from the end of
+the string. A positive OFFSET greater than the length of SCALAR
+results in the string being padded to the required size with C<"\0">
+bytes before the result of the read is appended.
+
+The call is implemented in terms of either Perl's or your system's native
+fread(3) library function. To get a true read(2) system call, see C<sysread>.
+
+Note the I<characters>: depending on the status of the filehandle,
+either (8-bit) bytes or characters are read. By default all
+filehandles operate on bytes, but for example if the filehandle has
+been opened with the C<:utf8> I/O layer (see L</open>, and the C<open>
+pragma, L<open>), the I/O will operate on UTF-8 encoded Unicode
+characters, not bytes. Similarly for the C<:encoding> pragma:
+in that case pretty much any characters can be read.
+
+=item readdir DIRHANDLE
+X<readdir>
+
+Returns the next directory entry for a directory opened by C<opendir>.
+If used in list context, returns all the rest of the entries in the
+directory. If there are no more entries, returns the undefined value in
+scalar context and the empty list in list context.
+
+If you're planning to filetest the return values out of a C<readdir>, you'd
+better prepend the directory in question. Otherwise, because we didn't
+C<chdir> there, it would have been testing the wrong file.
+
+ opendir(my $dh, $some_dir) || die "can't opendir $some_dir: $!";
+ @dots = grep { /^\./ && -f "$some_dir/$_" } readdir($dh);
+ closedir $dh;
+
+As of Perl 5.11.2 you can use a bare C<readdir> in a C<while> loop,
+which will set C<$_> on every iteration.
+
+ opendir(my $dh, $some_dir) || die;
+ while(readdir $dh) {
+ print "$some_dir/$_\n";
+ }
+ closedir $dh;
+
+=item readline EXPR
+
+=item readline
+X<readline> X<gets> X<fgets>
+
+Reads from the filehandle whose typeglob is contained in EXPR (or from
+*ARGV if EXPR is not provided). In scalar context, each call reads and
+returns the next line until end-of-file is reached, whereupon the
+subsequent call returns C<undef>. In list context, reads until end-of-file
+is reached and returns a list of lines. Note that the notion of "line"
+used here is whatever you may have defined with C<$/> or
+C<$INPUT_RECORD_SEPARATOR>). See L<perlvar/"$/">.
+
+When C<$/> is set to C<undef>, when C<readline> is in scalar
+context (i.e., file slurp mode), and when an empty file is read, it
+returns C<''> the first time, followed by C<undef> subsequently.
+
+This is the internal function implementing the C<< <EXPR> >>
+operator, but you can use it directly. The C<< <EXPR> >>
+operator is discussed in more detail in L<perlop/"I/O Operators">.
+
+ $line = <STDIN>;
+ $line = readline(*STDIN); # same thing
+
+If C<readline> encounters an operating system error, C<$!> will be set
+with the corresponding error message. It can be helpful to check
+C<$!> when you are reading from filehandles you don't trust, such as a
+tty or a socket. The following example uses the operator form of
+C<readline> and dies if the result is not defined.
+
+ while ( ! eof($fh) ) {
+ defined( $_ = <$fh> ) or die "readline failed: $!";
+ ...
+ }
+
+Note that you have can't handle C<readline> errors that way with the
+C<ARGV> filehandle. In that case, you have to open each element of
+C<@ARGV> yourself since C<eof> handles C<ARGV> differently.
+
+ foreach my $arg (@ARGV) {
+ open(my $fh, $arg) or warn "Can't open $arg: $!";
+
+ while ( ! eof($fh) ) {
+ defined( $_ = <$fh> )
+ or die "readline failed for $arg: $!";
+ ...
+ }
+ }
+
+=item readlink EXPR
+X<readlink>
+
+=item readlink
+
+Returns the value of a symbolic link, if symbolic links are
+implemented. If not, raises an exception. If there is a system
+error, returns the undefined value and sets C<$!> (errno). If EXPR is
+omitted, uses C<$_>.
+
+=item readpipe EXPR
+
+=item readpipe
+X<readpipe>
+
+EXPR is executed as a system command.
+The collected standard output of the command is returned.
+In scalar context, it comes back as a single (potentially
+multi-line) string. In list context, returns a list of lines
+(however you've defined lines with C<$/> or C<$INPUT_RECORD_SEPARATOR>).
+This is the internal function implementing the C<qx/EXPR/>
+operator, but you can use it directly. The C<qx/EXPR/>
+operator is discussed in more detail in L<perlop/"I/O Operators">.
+If EXPR is omitted, uses C<$_>.
+
+=item recv SOCKET,SCALAR,LENGTH,FLAGS
+X<recv>
+
+Receives a message on a socket. Attempts to receive LENGTH characters
+of data into variable SCALAR from the specified SOCKET filehandle.
+SCALAR will be grown or shrunk to the length actually read. Takes the
+same flags as the system call of the same name. Returns the address
+of the sender if SOCKET's protocol supports this; returns an empty
+string otherwise. If there's an error, returns the undefined value.
+This call is actually implemented in terms of recvfrom(2) system call.
+See L<perlipc/"UDP: Message Passing"> for examples.
+
+Note the I<characters>: depending on the status of the socket, either
+(8-bit) bytes or characters are received. By default all sockets
+operate on bytes, but for example if the socket has been changed using
+binmode() to operate with the C<:encoding(utf8)> I/O layer (see the
+C<open> pragma, L<open>), the I/O will operate on UTF-8 encoded Unicode
+characters, not bytes. Similarly for the C<:encoding> pragma: in that
+case pretty much any characters can be read.
+
+=item redo LABEL
+X<redo>
+
+=item redo
+
+The C<redo> command restarts the loop block without evaluating the
+conditional again. The C<continue> block, if any, is not executed. If
+the LABEL is omitted, the command refers to the innermost enclosing
+loop. Programs that want to lie to themselves about what was just input
+normally use this command:
+
+ # a simpleminded Pascal comment stripper
+ # (warning: assumes no { or } in strings)
+ LINE: while (<STDIN>) {
+ while (s|({.*}.*){.*}|$1 |) {}
+ s|{.*}| |;
+ if (s|{.*| |) {
+ $front = $_;
+ while (<STDIN>) {
+ if (/}/) { # end of comment?
+ s|^|$front\{|;
+ redo LINE;
+ }
+ }
+ }
+ print;
+ }
+
+C<redo> cannot be used to retry a block that returns a value such as
+C<eval {}>, C<sub {}> or C<do {}>, and should not be used to exit
+a grep() or map() operation.
+
+Note that a block by itself is semantically identical to a loop
+that executes once. Thus C<redo> inside such a block will effectively
+turn it into a looping construct.
+
+See also L</continue> for an illustration of how C<last>, C<next>, and
+C<redo> work.
+
+=item ref EXPR
+X<ref> X<reference>
+
+=item ref
+
+Returns a non-empty string if EXPR is a reference, the empty
+string otherwise. If EXPR
+is not specified, C<$_> will be used. The value returned depends on the
+type of thing the reference is a reference to.
+Builtin types include:
+
+ SCALAR
+ ARRAY
+ HASH
+ CODE
+ REF
+ GLOB
+ LVALUE
+ FORMAT
+ IO
+ VSTRING
+ Regexp
+
+If the referenced object has been blessed into a package, then that package
+name is returned instead. You can think of C<ref> as a C<typeof> operator.
+
+ if (ref($r) eq "HASH") {
+ print "r is a reference to a hash.\n";
+ }
+ unless (ref($r)) {
+ print "r is not a reference at all.\n";
+ }
+
+The return value C<LVALUE> indicates a reference to an lvalue that is not
+a variable. You get this from taking the reference of function calls like
+C<pos()> or C<substr()>. C<VSTRING> is returned if the reference points
+to a L<version string|perldata/"Version Strings">.
+
+The result C<Regexp> indicates that the argument is a regular expression
+resulting from C<qr//>.
+
+See also L<perlref>.
+
+=item rename OLDNAME,NEWNAME
+X<rename> X<move> X<mv> X<ren>
+
+Changes the name of a file; an existing file NEWNAME will be
+clobbered. Returns true for success, false otherwise.
+
+Behavior of this function varies wildly depending on your system
+implementation. For example, it will usually not work across file system
+boundaries, even though the system I<mv> command sometimes compensates
+for this. Other restrictions include whether it works on directories,
+open files, or pre-existing files. Check L<perlport> and either the
+rename(2) manpage or equivalent system documentation for details.
+
+For a platform independent C<move> function look at the L<File::Copy>
+module.
+
+=item require VERSION
+X<require>
+
+=item require EXPR
+
+=item require
+
+Demands a version of Perl specified by VERSION, or demands some semantics
+specified by EXPR or by C<$_> if EXPR is not supplied.
+
+VERSION may be either a numeric argument such as 5.006, which will be
+compared to C<$]>, or a literal of the form v5.6.1, which will be compared
+to C<$^V> (aka $PERL_VERSION). An exception is raised if
+VERSION is greater than the version of the current Perl interpreter.
+Compare with L</use>, which can do a similar check at compile time.
+
+Specifying VERSION as a literal of the form v5.6.1 should generally be
+avoided, because it leads to misleading error messages under earlier
+versions of Perl that do not support this syntax. The equivalent numeric
+version should be used instead.
+
+ require v5.6.1; # run time version check
+ require 5.6.1; # ditto
+ require 5.006_001; # ditto; preferred for backwards compatibility
+
+Otherwise, C<require> demands that a library file be included if it
+hasn't already been included. The file is included via the do-FILE
+mechanism, which is essentially just a variety of C<eval> with the
+caveat that lexical variables in the invoking script will be invisible
+to the included code. Has semantics similar to the following subroutine:
+
+ sub require {
+ my ($filename) = @_;
+ if (exists $INC{$filename}) {
+ return 1 if $INC{$filename};
+ die "Compilation failed in require";
+ }
+ my ($realfilename,$result);
+ ITER: {
+ foreach $prefix (@INC) {
+ $realfilename = "$prefix/$filename";
+ if (-f $realfilename) {
+ $INC{$filename} = $realfilename;
+ $result = do $realfilename;
+ last ITER;
+ }
+ }
+ die "Can't find $filename in \@INC";
+ }
+ if ($@) {
+ $INC{$filename} = undef;
+ die $@;
+ } elsif (!$result) {
+ delete $INC{$filename};
+ die "$filename did not return true value";
+ } else {
+ return $result;
+ }
+ }
+
+Note that the file will not be included twice under the same specified
+name.
+
+The file must return true as the last statement to indicate
+successful execution of any initialization code, so it's customary to
+end such a file with C<1;> unless you're sure it'll return true
+otherwise. But it's better just to put the C<1;>, in case you add more
+statements.
+
+If EXPR is a bareword, the require assumes a "F<.pm>" extension and
+replaces "F<::>" with "F</>" in the filename for you,
+to make it easy to load standard modules. This form of loading of
+modules does not risk altering your namespace.
+
+In other words, if you try this:
+
+ require Foo::Bar; # a splendid bareword
+
+The require function will actually look for the "F<Foo/Bar.pm>" file in the
+directories specified in the C<@INC> array.
+
+But if you try this:
+
+ $class = 'Foo::Bar';
+ require $class; # $class is not a bareword
+ #or
+ require "Foo::Bar"; # not a bareword because of the ""
+
+The require function will look for the "F<Foo::Bar>" file in the @INC array and
+will complain about not finding "F<Foo::Bar>" there. In this case you can do:
+
+ eval "require $class";
+
+Now that you understand how C<require> looks for files with a
+bareword argument, there is a little extra functionality going on behind
+the scenes. Before C<require> looks for a "F<.pm>" extension, it will
+first look for a similar filename with a "F<.pmc>" extension. If this file
+is found, it will be loaded in place of any file ending in a "F<.pm>"
+extension.
+
+You can also insert hooks into the import facility, by putting Perl code
+directly into the @INC array. There are three forms of hooks: subroutine
+references, array references and blessed objects.
+
+Subroutine references are the simplest case. When the inclusion system
+walks through @INC and encounters a subroutine, this subroutine gets
+called with two parameters, the first a reference to itself, and the
+second the name of the file to be included (e.g., "F<Foo/Bar.pm>"). The
+subroutine should return either nothing or else a list of up to three
+values in the following order:
+
+=over
+
+=item 1
+
+A filehandle, from which the file will be read.
+
+=item 2
+
+A reference to a subroutine. If there is no filehandle (previous item),
+then this subroutine is expected to generate one line of source code per
+call, writing the line into C<$_> and returning 1, then returning 0 at
+end of file. If there is a filehandle, then the subroutine will be
+called to act as a simple source filter, with the line as read in C<$_>.
+Again, return 1 for each valid line, and 0 after all lines have been
+returned.
+
+=item 3
+
+Optional state for the subroutine. The state is passed in as C<$_[1]>. A
+reference to the subroutine itself is passed in as C<$_[0]>.
+
+=back
+
+If an empty list, C<undef>, or nothing that matches the first 3 values above
+is returned, then C<require> looks at the remaining elements of @INC.
+Note that this filehandle must be a real filehandle (strictly a typeglob
+or reference to a typeglob, blessed or unblessed); tied filehandles will be
+ignored and return value processing will stop there.
+
+If the hook is an array reference, its first element must be a subroutine
+reference. This subroutine is called as above, but the first parameter is
+the array reference. This lets you indirectly pass arguments to
+the subroutine.
+
+In other words, you can write:
+
+ push @INC, \&my_sub;
+ sub my_sub {
+ my ($coderef, $filename) = @_; # $coderef is \&my_sub
+ ...
+ }
+
+or:
+
+ push @INC, [ \&my_sub, $x, $y, ... ];
+ sub my_sub {
+ my ($arrayref, $filename) = @_;
+ # Retrieve $x, $y, ...
+ my @parameters = @$arrayref[1..$#$arrayref];
+ ...
+ }
+
+If the hook is an object, it must provide an INC method that will be
+called as above, the first parameter being the object itself. (Note that
+you must fully qualify the sub's name, as unqualified C<INC> is always forced
+into package C<main>.) Here is a typical code layout:
+
+ # In Foo.pm
+ package Foo;
+ sub new { ... }
+ sub Foo::INC {
+ my ($self, $filename) = @_;
+ ...
+ }
+
+ # In the main program
+ push @INC, Foo->new(...);
+
+These hooks are also permitted to set the %INC entry
+corresponding to the files they have loaded. See L<perlvar/%INC>.
+
+For a yet-more-powerful import facility, see L</use> and L<perlmod>.
+
+=item reset EXPR
+X<reset>
+
+=item reset
+
+Generally used in a C<continue> block at the end of a loop to clear
+variables and reset C<??> searches so that they work again. The
+expression is interpreted as a list of single characters (hyphens
+allowed for ranges). All variables and arrays beginning with one of
+those letters are reset to their pristine state. If the expression is
+omitted, one-match searches (C<?pattern?>) are reset to match again.
+Only resets variables or searches in the current package. Always returns
+1. Examples:
+
+ reset 'X'; # reset all X variables
+ reset 'a-z'; # reset lower case variables
+ reset; # just reset ?one-time? searches
+
+Resetting C<"A-Z"> is not recommended because you'll wipe out your
+C<@ARGV> and C<@INC> arrays and your C<%ENV> hash. Resets only package
+variables; lexical variables are unaffected, but they clean themselves
+up on scope exit anyway, so you'll probably want to use them instead.
+See L</my>.
+
+=item return EXPR
+X<return>
+
+=item return
+
+Returns from a subroutine, C<eval>, or C<do FILE> with the value
+given in EXPR. Evaluation of EXPR may be in list, scalar, or void
+context, depending on how the return value will be used, and the context
+may vary from one execution to the next (see C<wantarray>). If no EXPR
+is given, returns an empty list in list context, the undefined value in
+scalar context, and (of course) nothing at all in void context.
+
+(In the absence of an explicit C<return>, a subroutine, eval,
+or do FILE automatically returns the value of the last expression
+evaluated.)
+
+=item reverse LIST
+X<reverse> X<rev> X<invert>
+
+In list context, returns a list value consisting of the elements
+of LIST in the opposite order. In scalar context, concatenates the
+elements of LIST and returns a string value with all characters
+in the opposite order.
+
+ print join(", ", reverse "world", "Hello"); # Hello, world
+
+ print scalar reverse "dlrow ,", "olleH"; # Hello, world
+
+Used without arguments in scalar context, reverse() reverses C<$_>.
+
+ $_ = "dlrow ,olleH";
+ print reverse; # No output, list context
+ print scalar reverse; # Hello, world
+
+Note that reversing an array to itself (as in C<@a = reverse @a>) will
+preserve non-existent elements whenever possible, i.e., for non magical
+arrays or tied arrays with C<EXISTS> and C<DELETE> methods.
+
+This operator is also handy for inverting a hash, although there are some
+caveats. If a value is duplicated in the original hash, only one of those
+can be represented as a key in the inverted hash. Also, this has to
+unwind one hash and build a whole new one, which may take some time
+on a large hash, such as from a DBM file.
+
+ %by_name = reverse %by_address; # Invert the hash
+
+=item rewinddir DIRHANDLE
+X<rewinddir>
+
+Sets the current position to the beginning of the directory for the
+C<readdir> routine on DIRHANDLE.
+
+=item rindex STR,SUBSTR,POSITION
+X<rindex>
+
+=item rindex STR,SUBSTR
+
+Works just like index() except that it returns the position of the I<last>
+occurrence of SUBSTR in STR. If POSITION is specified, returns the
+last occurrence beginning at or before that position.
+
+=item rmdir FILENAME
+X<rmdir> X<rd> X<directory, remove>
+
+=item rmdir
+
+Deletes the directory specified by FILENAME if that directory is
+empty. If it succeeds it returns true, otherwise it returns false and
+sets C<$!> (errno). If FILENAME is omitted, uses C<$_>.
+
+To remove a directory tree recursively (C<rm -rf> on Unix) look at
+the C<rmtree> function of the L<File::Path> module.
+
+=item s///
+
+The substitution operator. See L<perlop/"Regexp Quote-Like Operators">.
+
+=item say FILEHANDLE LIST
+X<say>
+
+=item say LIST
+
+=item say
+
+Just like C<print>, but implicitly appends a newline.
+C<say LIST> is simply an abbreviation for C<{ local $\ = "\n"; print
+LIST }>.
+
+This keyword is available only when the "say" feature is
+enabled: see L<feature>.
+
+=item scalar EXPR
+X<scalar> X<context>
+
+Forces EXPR to be interpreted in scalar context and returns the value
+of EXPR.
+
+ @counts = ( scalar @a, scalar @b, scalar @c );
+
+There is no equivalent operator to force an expression to
+be interpolated in list context because in practice, this is never
+needed. If you really wanted to do so, however, you could use
+the construction C<@{[ (some expression) ]}>, but usually a simple
+C<(some expression)> suffices.
+
+Because C<scalar> is a unary operator, if you accidentally use for EXPR a
+parenthesized list, this behaves as a scalar comma expression, evaluating
+all but the last element in void context and returning the final element
+evaluated in scalar context. This is seldom what you want.
+
+The following single statement:
+
+ print uc(scalar(&foo,$bar)),$baz;
+
+is the moral equivalent of these two:
+
+ &foo;
+ print(uc($bar),$baz);
+
+See L<perlop> for more details on unary operators and the comma operator.
+
+=item seek FILEHANDLE,POSITION,WHENCE
+X<seek> X<fseek> X<filehandle, position>
+
+Sets FILEHANDLE's position, just like the C<fseek> call of C<stdio>.
+FILEHANDLE may be an expression whose value gives the name of the
+filehandle. The values for WHENCE are C<0> to set the new position
+I<in bytes> to POSITION, C<1> to set it to the current position plus
+POSITION, and C<2> to set it to EOF plus POSITION (typically
+negative). For WHENCE you may use the constants C<SEEK_SET>,
+C<SEEK_CUR>, and C<SEEK_END> (start of the file, current position, end
+of the file) from the Fcntl module. Returns C<1> on success, C<0>
+otherwise.
+
+Note the I<in bytes>: even if the filehandle has been set to
+operate on characters (for example by using the C<:encoding(utf8)> open
+layer), tell() will return byte offsets, not character offsets
+(because implementing that would render seek() and tell() rather slow).
+
+If you want to position the file for C<sysread> or C<syswrite>, don't use
+C<seek>, because buffering makes its effect on the file's read-write position
+unpredictable and non-portable. Use C<sysseek> instead.
+
+Due to the rules and rigors of ANSI C, on some systems you have to do a
+seek whenever you switch between reading and writing. Amongst other
+things, this may have the effect of calling stdio's clearerr(3).
+A WHENCE of C<1> (C<SEEK_CUR>) is useful for not moving the file position:
+
+ seek(TEST,0,1);
+
+This is also useful for applications emulating C<tail -f>. Once you hit
+EOF on your read and then sleep for a while, you (probably) have to stick in a
+dummy seek() to reset things. The C<seek> doesn't change the position,
+but it I<does> clear the end-of-file condition on the handle, so that the
+next C<< <FILE> >> makes Perl try again to read something. (We hope.)
+
+If that doesn't work (some I/O implementations are particularly
+cantankerous), you might need something like this:
+
+ for (;;) {
+ for ($curpos = tell(FILE); $_ = <FILE>;
+ $curpos = tell(FILE)) {
+ # search for some stuff and put it into files
+ }
+ sleep($for_a_while);
+ seek(FILE, $curpos, 0);
+ }
+
+=item seekdir DIRHANDLE,POS
+X<seekdir>
+
+Sets the current position for the C<readdir> routine on DIRHANDLE. POS
+must be a value returned by C<telldir>. C<seekdir> also has the same caveats
+about possible directory compaction as the corresponding system library
+routine.
+
+=item select FILEHANDLE
+X<select> X<filehandle, default>
+
+=item select
+
+Returns the currently selected filehandle. If FILEHANDLE is supplied,
+sets the new current default filehandle for output. This has two
+effects: first, a C<write> or a C<print> without a filehandle will
+default to this FILEHANDLE. Second, references to variables related to
+output will refer to this output channel. For example, if you have to
+set the top of form format for more than one output channel, you might
+do the following:
+
+ select(REPORT1);
+ $^ = 'report1_top';
+ select(REPORT2);
+ $^ = 'report2_top';
+
+FILEHANDLE may be an expression whose value gives the name of the
+actual filehandle. Thus:
+
+ $oldfh = select(STDERR); $| = 1; select($oldfh);
+
+Some programmers may prefer to think of filehandles as objects with
+methods, preferring to write the last example as:
+
+ use IO::Handle;
+ STDERR->autoflush(1);
+
+=item select RBITS,WBITS,EBITS,TIMEOUT
+X<select>
+
+This calls the select(2) syscall with the bit masks specified, which
+can be constructed using C<fileno> and C<vec>, along these lines:
+
+ $rin = $win = $ein = '';
+ vec($rin,fileno(STDIN),1) = 1;
+ vec($win,fileno(STDOUT),1) = 1;
+ $ein = $rin | $win;
+
+If you want to select on many filehandles, you may wish to write a
+subroutine like this:
+
+ sub fhbits {
+ my(@fhlist) = split(' ',$_[0]);
+ my($bits);
+ for (@fhlist) {
+ vec($bits,fileno($_),1) = 1;
+ }
+ $bits;
+ }
+ $rin = fhbits('STDIN TTY SOCK');
+
+The usual idiom is:
+
+ ($nfound,$timeleft) =
+ select($rout=$rin, $wout=$win, $eout=$ein, $timeout);
+
+or to block until something becomes ready just do this
+
+ $nfound = select($rout=$rin, $wout=$win, $eout=$ein, undef);
+
+Most systems do not bother to return anything useful in $timeleft, so
+calling select() in scalar context just returns $nfound.
+
+Any of the bit masks can also be undef. The timeout, if specified, is
+in seconds, which may be fractional. Note: not all implementations are
+capable of returning the $timeleft. If not, they always return
+$timeleft equal to the supplied $timeout.
+
+You can effect a sleep of 250 milliseconds this way:
+
+ select(undef, undef, undef, 0.25);
+
+Note that whether C<select> gets restarted after signals (say, SIGALRM)
+is implementation-dependent. See also L<perlport> for notes on the
+portability of C<select>.
+
+On error, C<select> behaves like select(2): it returns
+-1 and sets C<$!>.
+
+On some Unixes, select(2) may report a socket file
+descriptor as "ready for reading" when no data is available, and
+thus a subsequent read blocks. This can be avoided if you always use
+O_NONBLOCK on the socket. See select(2) and fcntl(2) for further
+details.
+
+B<WARNING>: One should not attempt to mix buffered I/O (like C<read>
+or <FH>) with C<select>, except as permitted by POSIX, and even
+then only on POSIX systems. You have to use C<sysread> instead.
+
+=item semctl ID,SEMNUM,CMD,ARG
+X<semctl>
+
+Calls the System V IPC function semctl(2). You'll probably have to say
+
+ use IPC::SysV;
+
+first to get the correct constant definitions. If CMD is IPC_STAT or
+GETALL, then ARG must be a variable that will hold the returned
+semid_ds structure or semaphore value array. Returns like C<ioctl>:
+the undefined value for error, "C<0 but true>" for zero, or the actual
+return value otherwise. The ARG must consist of a vector of native
+short integers, which may be created with C<pack("s!",(0)x$nsem)>.
+See also L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::Semaphore>
+documentation.
+
+=item semget KEY,NSEMS,FLAGS
+X<semget>
+
+Calls the System V IPC function semget(2). Returns the semaphore id, or
+the undefined value if there is an error. See also
+L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::SysV::Semaphore>
+documentation.
+
+=item semop KEY,OPSTRING
+X<semop>
+
+Calls the System V IPC function semop(2) for semaphore operations
+such as signalling and waiting. OPSTRING must be a packed array of
+semop structures. Each semop structure can be generated with
+C<pack("s!3", $semnum, $semop, $semflag)>. The length of OPSTRING
+implies the number of semaphore operations. Returns true if
+successful, or false if there is an error. As an example, the
+following code waits on semaphore $semnum of semaphore id $semid:
+
+ $semop = pack("s!3", $semnum, -1, 0);
+ die "Semaphore trouble: $!\n" unless semop($semid, $semop);
+
+To signal the semaphore, replace C<-1> with C<1>. See also
+L<perlipc/"SysV IPC">, C<IPC::SysV>, and C<IPC::SysV::Semaphore>
+documentation.
+
+=item send SOCKET,MSG,FLAGS,TO
+X<send>
+
+=item send SOCKET,MSG,FLAGS
+
+Sends a message on a socket. Attempts to send the scalar MSG to the SOCKET
+filehandle. Takes the same flags as the system call of the same name. On
+unconnected sockets, you must specify a destination to I<send to>, in which
+case it does a sendto(2) syscall. Returns the number of characters sent,
+or the undefined value on error. The sendmsg(2) syscall is currently
+unimplemented. See L<perlipc/"UDP: Message Passing"> for examples.
+
+Note the I<characters>: depending on the status of the socket, either
+(8-bit) bytes or characters are sent. By default all sockets operate
+on bytes, but for example if the socket has been changed using
+binmode() to operate with the C<:encoding(utf8)> I/O layer (see
+L</open>, or the C<open> pragma, L<open>), the I/O will operate on UTF-8
+encoded Unicode characters, not bytes. Similarly for the C<:encoding>
+pragma: in that case pretty much any characters can be sent.
+
+=item setpgrp PID,PGRP
+X<setpgrp> X<group>
+
+Sets the current process group for the specified PID, C<0> for the current
+process. Raises an exception when used on a machine that doesn't
+implement POSIX setpgid(2) or BSD setpgrp(2). If the arguments are omitted,
+it defaults to C<0,0>. Note that the BSD 4.2 version of C<setpgrp> does not
+accept any arguments, so only C<setpgrp(0,0)> is portable. See also
+C<POSIX::setsid()>.
+
+=item setpriority WHICH,WHO,PRIORITY
+X<setpriority> X<priority> X<nice> X<renice>
+
+Sets the current priority for a process, a process group, or a user.
+(See setpriority(2).) Raises an exception when used on a machine
+that doesn't implement setpriority(2).
+
+=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
+X<setsockopt>
+
+Sets the socket option requested. Returns undefined if there is an
+error. Use integer constants provided by the C<Socket> module for
+LEVEL and OPNAME. Values for LEVEL can also be obtained from
+getprotobyname. OPTVAL might either be a packed string or an integer.
+An integer OPTVAL is shorthand for pack("i", OPTVAL).
+
+An example disabling Nagle's algorithm on a socket:
+
+ use Socket qw(IPPROTO_TCP TCP_NODELAY);
+ setsockopt($socket, IPPROTO_TCP, TCP_NODELAY, 1);
+
+=item shift ARRAY
+X<shift>
+
+=item shift
+
+Shifts the first value of the array off and returns it, shortening the
+array by 1 and moving everything down. If there are no elements in the
+array, returns the undefined value. If ARRAY is omitted, shifts the
+C<@_> array within the lexical scope of subroutines and formats, and the
+C<@ARGV> array outside a subroutine and also within the lexical scopes
+established by the C<eval STRING>, C<BEGIN {}>, C<INIT {}>, C<CHECK {}>,
+C<UNITCHECK {}> and C<END {}> constructs.
+
+See also C<unshift>, C<push>, and C<pop>. C<shift> and C<unshift> do the
+same thing to the left end of an array that C<pop> and C<push> do to the
+right end.
+
+=item shmctl ID,CMD,ARG
+X<shmctl>
+
+Calls the System V IPC function shmctl. You'll probably have to say
+
+ use IPC::SysV;
+
+first to get the correct constant definitions. If CMD is C<IPC_STAT>,
+then ARG must be a variable that will hold the returned C<shmid_ds>
+structure. Returns like ioctl: the undefined value for error, "C<0> but
+true" for zero, or the actual return value otherwise.
+See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+
+=item shmget KEY,SIZE,FLAGS
+X<shmget>
+
+Calls the System V IPC function shmget. Returns the shared memory
+segment id, or the undefined value if there is an error.
+See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+
+=item shmread ID,VAR,POS,SIZE
+X<shmread>
+X<shmwrite>
+
+=item shmwrite ID,STRING,POS,SIZE
+
+Reads or writes the System V shared memory segment ID starting at
+position POS for size SIZE by attaching to it, copying in/out, and
+detaching from it. When reading, VAR must be a variable that will
+hold the data read. When writing, if STRING is too long, only SIZE
+bytes are used; if STRING is too short, nulls are written to fill out
+SIZE bytes. Return true if successful, or false if there is an error.
+shmread() taints the variable. See also L<perlipc/"SysV IPC">,
+C<IPC::SysV> documentation, and the C<IPC::Shareable> module from CPAN.
+
+=item shutdown SOCKET,HOW
+X<shutdown>
+
+Shuts down a socket connection in the manner indicated by HOW, which
+has the same interpretation as in the syscall of the same name.
+
+ shutdown(SOCKET, 0); # I/we have stopped reading data
+ shutdown(SOCKET, 1); # I/we have stopped writing data
+ shutdown(SOCKET, 2); # I/we have stopped using this socket
+
+This is useful with sockets when you want to tell the other
+side you're done writing but not done reading, or vice versa.
+It's also a more insistent form of close because it also
+disables the file descriptor in any forked copies in other
+processes.
+
+Returns C<1> for success; on error, returns C<undef> if
+the first argument is not a valid filehandle, or returns C<0> and sets
+C<$!> for any other failure.
+
+=item sin EXPR
+X<sin> X<sine> X<asin> X<arcsine>
+
+=item sin
+
+Returns the sine of EXPR (expressed in radians). If EXPR is omitted,
+returns sine of C<$_>.
+
+For the inverse sine operation, you may use the C<Math::Trig::asin>
+function, or use this relation:
+
+ sub asin { atan2($_[0], sqrt(1 - $_[0] * $_[0])) }
+
+=item sleep EXPR
+X<sleep> X<pause>
+
+=item sleep
+
+Causes the script to sleep for (integer) EXPR seconds, or forever if no
+argument is given. Returns the integer number of seconds actually slept.
+
+May be interrupted if the process receives a signal such as C<SIGALRM>.
+
+ eval {
+ local $SIG{ALARM} = sub { die "Alarm!\n" };
+ sleep;
+ };
+ die $@ unless $@ eq "Alarm!\n";
+
+You probably cannot mix C<alarm> and C<sleep> calls, because C<sleep>
+is often implemented using C<alarm>.
+
+On some older systems, it may sleep up to a full second less than what
+you requested, depending on how it counts seconds. Most modern systems
+always sleep the full amount. They may appear to sleep longer than that,
+however, because your process might not be scheduled right away in a
+busy multitasking system.
+
+For delays of finer granularity than one second, the Time::HiRes module
+(from CPAN, and starting from Perl 5.8 part of the standard
+distribution) provides usleep(). You may also use Perl's four-argument
+version of select() leaving the first three arguments undefined, or you
+might be able to use the C<syscall> interface to access setitimer(2) if
+your system supports it. See L<perlfaq8> for details.
+
+See also the POSIX module's C<pause> function.
+
+=item socket SOCKET,DOMAIN,TYPE,PROTOCOL
+X<socket>
+
+Opens a socket of the specified kind and attaches it to filehandle
+SOCKET. DOMAIN, TYPE, and PROTOCOL are specified the same as for
+the syscall of the same name. You should C<use Socket> first
+to get the proper definitions imported. See the examples in
+L<perlipc/"Sockets: Client/Server Communication">.
+
+On systems that support a close-on-exec flag on files, the flag will
+be set for the newly opened file descriptor, as determined by the
+value of $^F. See L<perlvar/$^F>.
+
+=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
+X<socketpair>
+
+Creates an unnamed pair of sockets in the specified domain, of the
+specified type. DOMAIN, TYPE, and PROTOCOL are specified the same as
+for the syscall of the same name. If unimplemented, raises an exception.
+Returns true if successful.
+
+On systems that support a close-on-exec flag on files, the flag will
+be set for the newly opened file descriptors, as determined by the value
+of $^F. See L<perlvar/$^F>.
+
+Some systems defined C<pipe> in terms of C<socketpair>, in which a call
+to C<pipe(Rdr, Wtr)> is essentially:
+
+ use Socket;
+ socketpair(Rdr, Wtr, AF_UNIX, SOCK_STREAM, PF_UNSPEC);
+ shutdown(Rdr, 1); # no more writing for reader
+ shutdown(Wtr, 0); # no more reading for writer
+
+See L<perlipc> for an example of socketpair use. Perl 5.8 and later will
+emulate socketpair using IP sockets to localhost if your system implements
+sockets but not socketpair.
+
+=item sort SUBNAME LIST
+X<sort> X<qsort> X<quicksort> X<mergesort>
+
+=item sort BLOCK LIST
+
+=item sort LIST
+
+In list context, this sorts the LIST and returns the sorted list value.
+In scalar context, the behaviour of C<sort()> is undefined.
+
+If SUBNAME or BLOCK is omitted, C<sort>s in standard string comparison
+order. If SUBNAME is specified, it gives the name of a subroutine
+that returns an integer less than, equal to, or greater than C<0>,
+depending on how the elements of the list are to be ordered. (The
+C<< <=> >> and C<cmp> operators are extremely useful in such routines.)
+SUBNAME may be a scalar variable name (unsubscripted), in which case
+the value provides the name of (or a reference to) the actual
+subroutine to use. In place of a SUBNAME, you can provide a BLOCK as
+an anonymous, in-line sort subroutine.
+
+If the subroutine's prototype is C<($$)>, the elements to be compared
+are passed by reference in C<@_>, as for a normal subroutine. This is
+slower than unprototyped subroutines, where the elements to be
+compared are passed into the subroutine
+as the package global variables $a and $b (see example below). Note that
+in the latter case, it is usually counter-productive to declare $a and
+$b as lexicals.
+
+The values to be compared are always passed by reference and should not
+be modified.
+
+You also cannot exit out of the sort block or subroutine using any of the
+loop control operators described in L<perlsyn> or with C<goto>.
+
+When C<use locale> is in effect, C<sort LIST> sorts LIST according to the
+current collation locale. See L<perllocale>.
+
+sort() returns aliases into the original list, much as a for loop's index
+variable aliases the list elements. That is, modifying an element of a
+list returned by sort() (for example, in a C<foreach>, C<map> or C<grep>)
+actually modifies the element in the original list. This is usually
+something to be avoided when writing clear code.
+
+Perl 5.6 and earlier used a quicksort algorithm to implement sort.
+That algorithm was not stable, and I<could> go quadratic. (A I<stable> sort
+preserves the input order of elements that compare equal. Although
+quicksort's run time is O(NlogN) when averaged over all arrays of
+length N, the time can be O(N**2), I<quadratic> behavior, for some
+inputs.) In 5.7, the quicksort implementation was replaced with
+a stable mergesort algorithm whose worst-case behavior is O(NlogN).
+But benchmarks indicated that for some inputs, on some platforms,
+the original quicksort was faster. 5.8 has a sort pragma for
+limited control of the sort. Its rather blunt control of the
+underlying algorithm may not persist into future Perls, but the
+ability to characterize the input or output in implementation
+independent ways quite probably will. See L<the sort pragma|sort>.
+
+Examples:
+
+ # sort lexically
+ @articles = sort @files;
+
+ # same thing, but with explicit sort routine
+ @articles = sort {$a cmp $b} @files;
+
+ # now case-insensitively
+ @articles = sort {uc($a) cmp uc($b)} @files;
+
+ # same thing in reversed order
+ @articles = sort {$b cmp $a} @files;
+
+ # sort numerically ascending
+ @articles = sort {$a <=> $b} @files;
+
+ # sort numerically descending
+ @articles = sort {$b <=> $a} @files;
+
+ # this sorts the %age hash by value instead of key
+ # using an in-line function
+ @eldest = sort { $age{$b} <=> $age{$a} } keys %age;
+
+ # sort using explicit subroutine name
+ sub byage {
+ $age{$a} <=> $age{$b}; # presuming numeric
+ }
+ @sortedclass = sort byage @class;
+
+ sub backwards { $b cmp $a }
+ @harry = qw(dog cat x Cain Abel);
+ @george = qw(gone chased yz Punished Axed);
+ print sort @harry;
+ # prints AbelCaincatdogx
+ print sort backwards @harry;
+ # prints xdogcatCainAbel
+ print sort @george, 'to', @harry;
+ # prints AbelAxedCainPunishedcatchaseddoggonetoxyz
+
+ # inefficiently sort by descending numeric compare using
+ # the first integer after the first = sign, or the
+ # whole record case-insensitively otherwise
+
+ my @new = sort {
+ ($b =~ /=(\d+)/)[0] <=> ($a =~ /=(\d+)/)[0]
+ ||
+ uc($a) cmp uc($b)
+ } @old;
+
+ # same thing, but much more efficiently;
+ # we'll build auxiliary indices instead
+ # for speed
+ my @nums = @caps = ();
+ for (@old) {
+ push @nums, ( /=(\d+)/ ? $1 : undef );
+ push @caps, uc($_);
+ }
+
+ my @new = @old[ sort {
+ $nums[$b] <=> $nums[$a]
+ ||
+ $caps[$a] cmp $caps[$b]
+ } 0..$#old
+ ];
+
+ # same thing, but without any temps
+ @new = map { $_->[0] }
+ sort { $b->[1] <=> $a->[1]
+ ||
+ $a->[2] cmp $b->[2]
+ } map { [$_, /=(\d+)/, uc($_)] } @old;
+
+ # using a prototype allows you to use any comparison subroutine
+ # as a sort subroutine (including other package's subroutines)
+ package other;
+ sub backwards ($$) { $_[1] cmp $_[0]; } # $a and $b are not set here
+
+ package main;
+ @new = sort other::backwards @old;
+
+ # guarantee stability, regardless of algorithm
+ use sort 'stable';
+ @new = sort { substr($a, 3, 5) cmp substr($b, 3, 5) } @old;
+
+ # force use of mergesort (not portable outside Perl 5.8)
+ use sort '_mergesort'; # note discouraging _
+ @new = sort { substr($a, 3, 5) cmp substr($b, 3, 5) } @old;
+
+Warning: syntactical care is required when sorting the list returned from
+a function. If you want to sort the list returned by the function call
+C<find_records(@key)>, you can use:
+
+ @contact = sort { $a cmp $b } find_records @key;
+ @contact = sort +find_records(@key);
+ @contact = sort &find_records(@key);
+ @contact = sort(find_records(@key));
+
+If instead you want to sort the array @key with the comparison routine
+C<find_records()> then you can use:
+
+ @contact = sort { find_records() } @key;
+ @contact = sort find_records(@key);
+ @contact = sort(find_records @key);
+ @contact = sort(find_records (@key));
+
+If you're using strict, you I<must not> declare $a
+and $b as lexicals. They are package globals. That means
+that if you're in the C<main> package and type
+
+ @articles = sort {$b <=> $a} @files;
+
+then C<$a> and C<$b> are C<$main::a> and C<$main::b> (or C<$::a> and C<$::b>),
+but if you're in the C<FooPack> package, it's the same as typing
+
+ @articles = sort {$FooPack::b <=> $FooPack::a} @files;
+
+The comparison function is required to behave. If it returns
+inconsistent results (sometimes saying C<$x[1]> is less than C<$x[2]> and
+sometimes saying the opposite, for example) the results are not
+well-defined.
+
+Because C<< <=> >> returns C<undef> when either operand is C<NaN>
+(not-a-number), and because C<sort> raises an exception unless the
+result of a comparison is defined, when sorting with a comparison function
+like C<< $a <=> $b >>, be careful about lists that might contain a C<NaN>.
+The following example takes advantage that C<NaN != NaN> to
+eliminate any C<NaN>s from the input list.
+
+ @result = sort { $a <=> $b } grep { $_ == $_ } @input;
+
+=item splice ARRAY,OFFSET,LENGTH,LIST
+X<splice>
+
+=item splice ARRAY,OFFSET,LENGTH
+
+=item splice ARRAY,OFFSET
+
+=item splice ARRAY
+
+Removes the elements designated by OFFSET and LENGTH from an array, and
+replaces them with the elements of LIST, if any. In list context,
+returns the elements removed from the array. In scalar context,
+returns the last element removed, or C<undef> if no elements are
+removed. The array grows or shrinks as necessary.
+If OFFSET is negative then it starts that far from the end of the array.
+If LENGTH is omitted, removes everything from OFFSET onward.
+If LENGTH is negative, removes the elements from OFFSET onward
+except for -LENGTH elements at the end of the array.
+If both OFFSET and LENGTH are omitted, removes everything. If OFFSET is
+past the end of the array, Perl issues a warning, and splices at the
+end of the array.
+
+The following equivalences hold (assuming C<< $[ == 0 and $#a >= $i >> )
+
+ push(@a,$x,$y) splice(@a,@a,0,$x,$y)
+ pop(@a) splice(@a,-1)
+ shift(@a) splice(@a,0,1)
+ unshift(@a,$x,$y) splice(@a,0,0,$x,$y)
+ $a[$i] = $y splice(@a,$i,1,$y)
+
+Example, assuming array lengths are passed before arrays:
+
+ sub aeq { # compare two list values
+ my(@a) = splice(@_,0,shift);
+ my(@b) = splice(@_,0,shift);
+ return 0 unless @a == @b; # same len?
+ while (@a) {
+ return 0 if pop(@a) ne pop(@b);
+ }
+ return 1;
+ }
+ if (&aeq($len,@foo[1..$len],0+@bar,@bar)) { ... }
+
+=item split /PATTERN/,EXPR,LIMIT
+X<split>
+
+=item split /PATTERN/,EXPR
+
+=item split /PATTERN/
+
+=item split
+
+Splits the string EXPR into a list of strings and returns that list. By
+default, empty leading fields are preserved, and empty trailing ones are
+deleted. (If all fields are empty, they are considered to be trailing.)
+
+In scalar context, returns the number of fields found.
+
+If EXPR is omitted, splits the C<$_> string. If PATTERN is also omitted,
+splits on whitespace (after skipping any leading whitespace). Anything
+matching PATTERN is taken to be a delimiter separating the fields. (Note
+that the delimiter may be longer than one character.)
+
+If LIMIT is specified and positive, it represents the maximum number
+of fields the EXPR will be split into, though the actual number of
+fields returned depends on the number of times PATTERN matches within
+EXPR. If LIMIT is unspecified or zero, trailing null fields are
+stripped (which potential users of C<pop> would do well to remember).
+If LIMIT is negative, it is treated as if an arbitrarily large LIMIT
+had been specified. Note that splitting an EXPR that evaluates to the
+empty string always returns the empty list, regardless of the LIMIT
+specified.
+
+A pattern matching the empty string (not to be confused with
+an empty pattern C<//>, which is just one member of the set of patterns
+matching the epmty string), splits EXPR into individual
+characters. For example:
+
+ print join(':', split(/ */, 'hi there')), "\n";
+
+produces the output 'h:i:t:h:e:r:e'.
+
+As a special case for C<split>, the empty pattern C<//> specifically
+matches the empty string; this is not be confused with the normal use
+of an empty pattern to mean the last successful match. So to split
+a string into individual characters, the following:
+
+ print join(':', split(//, 'hi there')), "\n";
+
+produces the output 'h:i: :t:h:e:r:e'.
+
+Empty leading fields are produced when there are positive-width matches at
+the beginning of the string; a zero-width match at the beginning of
+the string does not produce an empty field. For example:
+
+ print join(':', split(/(?=\w)/, 'hi there!'));
+
+produces the output 'h:i :t:h:e:r:e!'. Empty trailing fields, on the other
+hand, are produced when there is a match at the end of the string (and
+when LIMIT is given and is not 0), regardless of the length of the match.
+For example:
+
+ print join(':', split(//, 'hi there!', -1)), "\n";
+ print join(':', split(/\W/, 'hi there!', -1)), "\n";
+
+produce the output 'h:i: :t:h:e:r:e:!:' and 'hi:there:', respectively,
+both with an empty trailing field.
+
+The LIMIT parameter can be used to split a line partially
+
+ ($login, $passwd, $remainder) = split(/:/, $_, 3);
+
+When assigning to a list, if LIMIT is omitted, or zero, Perl supplies
+a LIMIT one larger than the number of variables in the list, to avoid
+unnecessary work. For the list above LIMIT would have been 4 by
+default. In time critical applications it behooves you not to split
+into more fields than you really need.
+
+If the PATTERN contains parentheses, additional list elements are
+created from each matching substring in the delimiter.
+
+ split(/([,-])/, "1-10,20", 3);
+
+produces the list value
+
+ (1, '-', 10, ',', 20)
+
+If you had the entire header of a normal Unix email message in $header,
+you could split it up into fields and their values this way:
+
+ $header =~ s/\n(?=\s)//g; # fix continuation lines
+ %hdrs = (UNIX_FROM => split /^(\S*?):\s*/m, $header);
+
+The pattern C</PATTERN/> may be replaced with an expression to specify
+patterns that vary at runtime. (To do runtime compilation only once,
+use C</$variable/o>.)
+
+As a special case, specifying a PATTERN of space (S<C<' '>>) will split on
+white space just as C<split> with no arguments does. Thus, S<C<split(' ')>> can
+be used to emulate B<awk>'s default behavior, whereas S<C<split(/ /)>>
+will give you as many initial null fields (empty string) as there are leading spaces.
+A C<split> on C</\s+/> is like a S<C<split(' ')>> except that any leading
+whitespace produces a null first field. A C<split> with no arguments
+really does a S<C<split(' ', $_)>> internally.
+
+A PATTERN of C</^/> is treated as if it were C</^/m>, since it isn't
+much use otherwise.
+
+Example:
+
+ open(PASSWD, '/etc/passwd');
+ while (<PASSWD>) {
+ chomp;
+ ($login, $passwd, $uid, $gid,
+ $gcos, $home, $shell) = split(/:/);
+ #...
+ }
+
+As with regular pattern matching, any capturing parentheses that are not
+matched in a C<split()> will be set to C<undef> when returned:
+
+ @fields = split /(A)|B/, "1A2B3";
+ # @fields is (1, 'A', 2, undef, 3)
+
+=item sprintf FORMAT, LIST
+X<sprintf>
+
+Returns a string formatted by the usual C<printf> conventions of the C
+library function C<sprintf>. See below for more details
+and see C<sprintf(3)> or C<printf(3)> on your system for an explanation of
+the general principles.
+
+For example:
+
+ # Format number with up to 8 leading zeroes
+ $result = sprintf("%08d", $number);
+
+ # Round number to 3 digits after decimal point
+ $rounded = sprintf("%.3f", $number);
+
+Perl does its own C<sprintf> formatting: it emulates the C
+function sprintf(3), but doesn't use it except for floating-point
+numbers, and even then only standard modifiers are allowed.
+Non-standard extensions in your local sprintf(3) are
+therefore unavailable from Perl.
+
+Unlike C<printf>, C<sprintf> does not do what you probably mean when you
+pass it an array as your first argument. The array is given scalar context,
+and instead of using the 0th element of the array as the format, Perl will
+use the count of elements in the array as the format, which is almost never
+useful.
+
+Perl's C<sprintf> permits the following universally-known conversions:
+
+ %% a percent sign
+ %c a character with the given number
+ %s a string
+ %d a signed integer, in decimal
+ %u an unsigned integer, in decimal
+ %o an unsigned integer, in octal
+ %x an unsigned integer, in hexadecimal
+ %e a floating-point number, in scientific notation
+ %f a floating-point number, in fixed decimal notation
+ %g a floating-point number, in %e or %f notation
+
+In addition, Perl permits the following widely-supported conversions:
+
+ %X like %x, but using upper-case letters
+ %E like %e, but using an upper-case "E"
+ %G like %g, but with an upper-case "E" (if applicable)
+ %b an unsigned integer, in binary
+ %B like %b, but using an upper-case "B" with the # flag
+ %p a pointer (outputs the Perl value's address in hexadecimal)
+ %n special: *stores* the number of characters output so far
+ into the next variable in the parameter list
+
+Finally, for backward (and we do mean "backward") compatibility, Perl
+permits these unnecessary but widely-supported conversions:
+
+ %i a synonym for %d
+ %D a synonym for %ld
+ %U a synonym for %lu
+ %O a synonym for %lo
+ %F a synonym for %f
+
+Note that the number of exponent digits in the scientific notation produced
+by C<%e>, C<%E>, C<%g> and C<%G> for numbers with the modulus of the
+exponent less than 100 is system-dependent: it may be three or less
+(zero-padded as necessary). In other words, 1.23 times ten to the
+99th may be either "1.23e99" or "1.23e099".
+
+Between the C<%> and the format letter, you may specify several
+additional attributes controlling the interpretation of the format.
+In order, these are:
+
+=over 4
+
+=item format parameter index
+
+An explicit format parameter index, such as C<2$>. By default sprintf
+will format the next unused argument in the list, but this allows you
+to take the arguments out of order:
+
+ printf '%2$d %1$d', 12, 34; # prints "34 12"
+ printf '%3$d %d %1$d', 1, 2, 3; # prints "3 1 1"
+
+=item flags
+
+one or more of:
+
+ space prefix non-negative number with a space
+ + prefix non-negative number with a plus sign
+ - left-justify within the field
+ 0 use zeros, not spaces, to right-justify
+ # ensure the leading "0" for any octal,
+ prefix non-zero hexadecimal with "0x" or "0X",
+ prefix non-zero binary with "0b" or "0B"
+
+For example:
+
+ printf '<% d>', 12; # prints "< 12>"
+ printf '<%+d>', 12; # prints "<+12>"
+ printf '<%6s>', 12; # prints "< 12>"
+ printf '<%-6s>', 12; # prints "<12 >"
+ printf '<%06s>', 12; # prints "<000012>"
+ printf '<%#o>', 12; # prints "<014>"
+ printf '<%#x>', 12; # prints "<0xc>"
+ printf '<%#X>', 12; # prints "<0XC>"
+ printf '<%#b>', 12; # prints "<0b1100>"
+ printf '<%#B>', 12; # prints "<0B1100>"
+
+When a space and a plus sign are given as the flags at once,
+a plus sign is used to prefix a positive number.
+
+ printf '<%+ d>', 12; # prints "<+12>"
+ printf '<% +d>', 12; # prints "<+12>"
+
+When the # flag and a precision are given in the %o conversion,
+the precision is incremented if it's necessary for the leading "0".
+
+ printf '<%#.5o>', 012; # prints "<00012>"
+ printf '<%#.5o>', 012345; # prints "<012345>"
+ printf '<%#.0o>', 0; # prints "<0>"
+
+=item vector flag
+
+This flag tells Perl to interpret the supplied string as a vector of
+integers, one for each character in the string. Perl applies the format to
+each integer in turn, then joins the resulting strings with a separator (a
+dot C<.> by default). This can be useful for displaying ordinal values of
+characters in arbitrary strings:
+
+ printf "%vd", "AB\x{100}"; # prints "65.66.256"
+ printf "version is v%vd\n", $^V; # Perl's version
+
+Put an asterisk C<*> before the C<v> to override the string to
+use to separate the numbers:
+
+ printf "address is %*vX\n", ":", $addr; # IPv6 address
+ printf "bits are %0*v8b\n", " ", $bits; # random bitstring
+
+You can also explicitly specify the argument number to use for
+the join string using something like C<*2$v>; for example:
+
+ printf '%*4$vX %*4$vX %*4$vX', @addr[1..3], ":"; # 3 IPv6 addresses
+
+=item (minimum) width
+
+Arguments are usually formatted to be only as wide as required to
+display the given value. You can override the width by putting
+a number here, or get the width from the next argument (with C<*>)
+or from a specified argument (e.g., with C<*2$>):
+
+ printf '<%s>', "a"; # prints "<a>"
+ printf '<%6s>', "a"; # prints "< a>"
+ printf '<%*s>', 6, "a"; # prints "< a>"
+ printf '<%*2$s>', "a", 6; # prints "< a>"
+ printf '<%2s>', "long"; # prints "<long>" (does not truncate)
+
+If a field width obtained through C<*> is negative, it has the same
+effect as the C<-> flag: left-justification.
+
+=item precision, or maximum width
+X<precision>
+
+You can specify a precision (for numeric conversions) or a maximum
+width (for string conversions) by specifying a C<.> followed by a number.
+For floating-point formats except 'g' and 'G', this specifies
+how many places right of the decimal point to show (the default being 6).
+For example:
+
+ # these examples are subject to system-specific variation
+ printf '<%f>', 1; # prints "<1.000000>"
+ printf '<%.1f>', 1; # prints "<1.0>"
+ printf '<%.0f>', 1; # prints "<1>"
+ printf '<%e>', 10; # prints "<1.000000e+01>"
+ printf '<%.1e>', 10; # prints "<1.0e+01>"
+
+For "g" and "G", this specifies the maximum number of digits to show,
+including thoe prior to the decimal point and those after it; for
+example:
+
+ # These examples are subject to system-specific variation.
+ printf '<%g>', 1; # prints "<1>"
+ printf '<%.10g>', 1; # prints "<1>"
+ printf '<%g>', 100; # prints "<100>"
+ printf '<%.1g>', 100; # prints "<1e+02>"
+ printf '<%.2g>', 100.01; # prints "<1e+02>"
+ printf '<%.5g>', 100.01; # prints "<100.01>"
+ printf '<%.4g>', 100.01; # prints "<100>"
+
+For integer conversions, specifying a precision implies that the
+output of the number itself should be zero-padded to this width,
+where the 0 flag is ignored:
+
+ printf '<%.6d>', 1; # prints "<000001>"
+ printf '<%+.6d>', 1; # prints "<+000001>"
+ printf '<%-10.6d>', 1; # prints "<000001 >"
+ printf '<%10.6d>', 1; # prints "< 000001>"
+ printf '<%010.6d>', 1; # prints "< 000001>"
+ printf '<%+10.6d>', 1; # prints "< +000001>"
+
+ printf '<%.6x>', 1; # prints "<000001>"
+ printf '<%#.6x>', 1; # prints "<0x000001>"
+ printf '<%-10.6x>', 1; # prints "<000001 >"
+ printf '<%10.6x>', 1; # prints "< 000001>"
+ printf '<%010.6x>', 1; # prints "< 000001>"
+ printf '<%#10.6x>', 1; # prints "< 0x000001>"
+
+For string conversions, specifying a precision truncates the string
+to fit the specified width:
+
+ printf '<%.5s>', "truncated"; # prints "<trunc>"
+ printf '<%10.5s>', "truncated"; # prints "< trunc>"
+
+You can also get the precision from the next argument using C<.*>:
+
+ printf '<%.6x>', 1; # prints "<000001>"
+ printf '<%.*x>', 6, 1; # prints "<000001>"
+
+If a precision obtained through C<*> is negative, it counts
+as having no precision at all.
+
+ printf '<%.*s>', 7, "string"; # prints "<string>"
+ printf '<%.*s>', 3, "string"; # prints "<str>"
+ printf '<%.*s>', 0, "string"; # prints "<>"
+ printf '<%.*s>', -1, "string"; # prints "<string>"
+
+ printf '<%.*d>', 1, 0; # prints "<0>"
+ printf '<%.*d>', 0, 0; # prints "<>"
+ printf '<%.*d>', -1, 0; # prints "<0>"
+
+You cannot currently get the precision from a specified number,
+but it is intended that this will be possible in the future, for
+example using C<.*2$>:
+
+ printf "<%.*2$x>", 1, 6; # INVALID, but in future will print "<000001>"
+
+=item size
+
+For numeric conversions, you can specify the size to interpret the
+number as using C<l>, C<h>, C<V>, C<q>, C<L>, or C<ll>. For integer
+conversions (C<d u o x X b i D U O>), numbers are usually assumed to be
+whatever the default integer size is on your platform (usually 32 or 64
+bits), but you can override this to use instead one of the standard C types,
+as supported by the compiler used to build Perl:
+
+ l interpret integer as C type "long" or "unsigned long"
+ h interpret integer as C type "short" or "unsigned short"
+ q, L or ll interpret integer as C type "long long", "unsigned long long".
+ or "quads" (typically 64-bit integers)
+
+The last will raise an exception if Perl does not understand "quads" in your
+installation. (This requires either that the platform natively support quads,
+or that Perl were specifically compiled to support quads.) You can find out
+whether your Perl supports quads via L<Config>:
+
+ use Config;
+ if ($Config{use64bitint} eq "define" || $Config{longsize} >= 8) {
+ print "Nice quads!\n";
+ }
+
+For floating-point conversions (C<e f g E F G>), numbers are usually assumed
+to be the default floating-point size on your platform (double or long double),
+but you can force "long double" with C<q>, C<L>, or C<ll> if your
+platform supports them. You can find out whether your Perl supports long
+doubles via L<Config>:
+
+ use Config;
+ print "long doubles\n" if $Config{d_longdbl} eq "define";
+
+You can find out whether Perl considers "long double" to be the default
+floating-point size to use on your platform via L<Config>:
+
+ use Config;
+ if ($Config{uselongdouble} eq "define") {
+ print "long doubles by default\n";
+ }
+
+It can also be that long doubles and doubles are the same thing:
+
+ use Config;
+ ($Config{doublesize} == $Config{longdblsize}) &&
+ print "doubles are long doubles\n";
+
+The size specifier C<V> has no effect for Perl code, but is supported for
+compatibility with XS code. It means "use the standard size for a Perl
+integer or floating-point number", which is the default.
+
+=item order of arguments
+
+Normally, sprintf() takes the next unused argument as the value to
+format for each format specification. If the format specification
+uses C<*> to require additional arguments, these are consumed from
+the argument list in the order they appear in the format
+specification I<before> the value to format. Where an argument is
+specified by an explicit index, this does not affect the normal
+order for the arguments, even when the explicitly specified index
+would have been the next argument.
+
+So:
+
+ printf "<%*.*s>", $a, $b, $c;
+
+uses C<$a> for the width, C<$b> for the precision, and C<$c>
+as the value to format; while:
+
+ printf "<%*1$.*s>", $a, $b;
+
+would use C<$a> for the width and precision, and C<$b> as the
+value to format.
+
+Here are some more examples; be aware that when using an explicit
+index, the C<$> may need escaping:
+
+ printf "%2\$d %d\n", 12, 34; # will print "34 12\n"
+ printf "%2\$d %d %d\n", 12, 34; # will print "34 12 34\n"
+ printf "%3\$d %d %d\n", 12, 34, 56; # will print "56 12 34\n"
+ printf "%2\$*3\$d %d\n", 12, 34, 3; # will print " 34 12\n"
+
+=back
+
+If C<use locale> is in effect and POSIX::setlocale() has been called,
+the character used for the decimal separator in formatted floating-point
+numbers is affected by the LC_NUMERIC locale. See L<perllocale>
+and L<POSIX>.
+
+=item sqrt EXPR
+X<sqrt> X<root> X<square root>
+
+=item sqrt
+
+Return the positive square root of EXPR. If EXPR is omitted, uses
+C<$_>. Works only for non-negative operands unless you've
+loaded the C<Math::Complex> module.
+
+ use Math::Complex;
+ print sqrt(-4); # prints 2i
+
+=item srand EXPR
+X<srand> X<seed> X<randseed>
+
+=item srand
+
+Sets the random number seed for the C<rand> operator.
+
+The point of the function is to "seed" the C<rand> function so that
+C<rand> can produce a different sequence each time you run your
+program.
+
+If srand() is not called explicitly, it is called implicitly at the
+first use of the C<rand> operator. However, this was not true of
+versions of Perl before 5.004, so if your script will run under older
+Perl versions, it should call C<srand>.
+
+Most programs won't even call srand() at all, except those that
+need a cryptographically-strong starting point rather than the
+generally acceptable default, which is based on time of day,
+process ID, and memory allocation, or the F</dev/urandom> device
+if available. You may also want to call srand() after a fork() to
+avoid child processes sharing the same seed value as the parent (and
+consequently each other).
+
+You can call srand($seed) with the same $seed to reproduce the
+I<same> sequence from rand(), but this is usually reserved for
+generating predictable results for testing or debugging.
+Otherwise, don't call srand() more than once in your program.
+
+Do B<not> call srand() (i.e., without an argument) more than once per
+process. The internal state of the random number generator should
+contain more entropy than can be provided by any seed, so calling
+srand() again actually I<loses> randomness.
+
+Most implementations of C<srand> take an integer and will silently
+truncate decimal numbers. This means C<srand(42)> will usually
+produce the same results as C<srand(42.1)>. To be safe, always pass
+C<srand> an integer.
+
+In versions of Perl prior to 5.004 the default seed was just the
+current C<time>. This isn't a particularly good seed, so many old
+programs supply their own seed value (often C<time ^ $$> or C<time ^
+($$ + ($$ << 15))>), but that isn't necessary any more.
+
+For cryptographic purposes, however, you need something much more random
+than the default seed. Checksumming the compressed output of one or more
+rapidly changing operating system status programs is the usual method. For
+example:
+
+ srand (time ^ $$ ^ unpack "%L*", `ps axww | gzip -f`);
+
+If you're particularly concerned with this, search the CPAN for
+random number generator modules instead of rolling out your own.
+
+Frequently called programs (like CGI scripts) that simply use
+
+ time ^ $$
+
+for a seed can fall prey to the mathematical property that
+
+ a^b == (a+1)^(b+1)
+
+one-third of the time. So don't do that.
+
+=item stat FILEHANDLE
+X<stat> X<file, status> X<ctime>
+
+=item stat EXPR
+
+=item stat DIRHANDLE
+
+=item stat
+
+Returns a 13-element list giving the status info for a file, either
+the file opened via FILEHANDLE or DIRHANDLE, or named by EXPR. If EXPR is
+omitted, it stats C<$_>. Returns the empty list if C<stat> fails. Typically
+used as follows:
+
+ ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
+ $atime,$mtime,$ctime,$blksize,$blocks)
+ = stat($filename);
+
+Not all fields are supported on all filesystem types. Here are the
+meanings of the fields:
+
+ 0 dev device number of filesystem
+ 1 ino inode number
+ 2 mode file mode (type and permissions)
+ 3 nlink number of (hard) links to the file
+ 4 uid numeric user ID of file's owner
+ 5 gid numeric group ID of file's owner
+ 6 rdev the device identifier (special files only)
+ 7 size total size of file, in bytes
+ 8 atime last access time in seconds since the epoch
+ 9 mtime last modify time in seconds since the epoch
+ 10 ctime inode change time in seconds since the epoch (*)
+ 11 blksize preferred block size for file system I/O
+ 12 blocks actual number of blocks allocated
+
+(The epoch was at 00:00 January 1, 1970 GMT.)
+
+(*) Not all fields are supported on all filesystem types. Notably, the
+ctime field is non-portable. In particular, you cannot expect it to be a
+"creation time", see L<perlport/"Files and Filesystems"> for details.
+
+If C<stat> is passed the special filehandle consisting of an underline, no
+stat is done, but the current contents of the stat structure from the
+last C<stat>, C<lstat>, or filetest are returned. Example:
+
+ if (-x $file && (($d) = stat(_)) && $d < 0) {
+ print "$file is executable NFS file\n";
+ }
+
+(This works on machines only for which the device number is negative
+under NFS.)
+
+Because the mode contains both the file type and its permissions, you
+should mask off the file type portion and (s)printf using a C<"%o">
+if you want to see the real permissions.
+
+ $mode = (stat($filename))[2];
+ printf "Permissions are %04o\n", $mode & 07777;
+
+In scalar context, C<stat> returns a boolean value indicating success
+or failure, and, if successful, sets the information associated with
+the special filehandle C<_>.
+
+The L<File::stat> module provides a convenient, by-name access mechanism:
+
+ use File::stat;
+ $sb = stat($filename);
+ printf "File is %s, size is %s, perm %04o, mtime %s\n",
+ $filename, $sb->size, $sb->mode & 07777,
+ scalar localtime $sb->mtime;
+
+You can import symbolic mode constants (C<S_IF*>) and functions
+(C<S_IS*>) from the Fcntl module:
+
+ use Fcntl ':mode';
+
+ $mode = (stat($filename))[2];
+
+ $user_rwx = ($mode & S_IRWXU) >> 6;
+ $group_read = ($mode & S_IRGRP) >> 3;
+ $other_execute = $mode & S_IXOTH;
+
+ printf "Permissions are %04o\n", S_IMODE($mode), "\n";
+
+ $is_setuid = $mode & S_ISUID;
+ $is_directory = S_ISDIR($mode);
+
+You could write the last two using the C<-u> and C<-d> operators.
+Commonly available C<S_IF*> constants are:
+
+ # Permissions: read, write, execute, for user, group, others.
+
+ S_IRWXU S_IRUSR S_IWUSR S_IXUSR
+ S_IRWXG S_IRGRP S_IWGRP S_IXGRP
+ S_IRWXO S_IROTH S_IWOTH S_IXOTH
+
+ # Setuid/Setgid/Stickiness/SaveText.
+ # Note that the exact meaning of these is system dependent.
+
+ S_ISUID S_ISGID S_ISVTX S_ISTXT
+
+ # File types. Not necessarily all are available on your system.
+
+ S_IFREG S_IFDIR S_IFLNK S_IFBLK S_IFCHR S_IFIFO S_IFSOCK S_IFWHT S_ENFMT
+
+ # The following are compatibility aliases for S_IRUSR, S_IWUSR, S_IXUSR.
+
+ S_IREAD S_IWRITE S_IEXEC
+
+and the C<S_IF*> functions are
+
+ S_IMODE($mode) the part of $mode containing the permission bits
+ and the setuid/setgid/sticky bits
+
+ S_IFMT($mode) the part of $mode containing the file type
+ which can be bit-anded with (for example) S_IFREG
+ or with the following functions
+
+ # The operators -f, -d, -l, -b, -c, -p, and -S.
+
+ S_ISREG($mode) S_ISDIR($mode) S_ISLNK($mode)
+ S_ISBLK($mode) S_ISCHR($mode) S_ISFIFO($mode) S_ISSOCK($mode)
+
+ # No direct -X operator counterpart, but for the first one
+ # the -g operator is often equivalent. The ENFMT stands for
+ # record flocking enforcement, a platform-dependent feature.
+
+ S_ISENFMT($mode) S_ISWHT($mode)
+
+See your native chmod(2) and stat(2) documentation for more details
+about the C<S_*> constants. To get status info for a symbolic link
+instead of the target file behind the link, use the C<lstat> function.
+
+=item state EXPR
+X<state>
+
+=item state TYPE EXPR
+
+=item state EXPR : ATTRS
+
+=item state TYPE EXPR : ATTRS
+
+C<state> declares a lexically scoped variable, just like C<my> does.
+However, those variables will never be reinitialized, contrary to
+lexical variables that are reinitialized each time their enclosing block
+is entered.
+
+C<state> variables are enabled only when the C<use feature "state"> pragma
+is in effect. See L<feature>.
+
+=item study SCALAR
+X<study>
+
+=item study
+
+Takes extra time to study SCALAR (C<$_> if unspecified) in anticipation of
+doing many pattern matches on the string before it is next modified.
+This may or may not save time, depending on the nature and number of
+patterns you are searching on, and on the distribution of character
+frequencies in the string to be searched; you probably want to compare
+run times with and without it to see which runs faster. Those loops
+that scan for many short constant strings (including the constant
+parts of more complex patterns) will benefit most. You may have only
+one C<study> active at a time: if you study a different scalar the first
+is "unstudied". (The way C<study> works is this: a linked list of every
+character in the string to be searched is made, so we know, for
+example, where all the C<'k'> characters are. From each search string,
+the rarest character is selected, based on some static frequency tables
+constructed from some C programs and English text. Only those places
+that contain this "rarest" character are examined.)
+
+For example, here is a loop that inserts index producing entries
+before any line containing a certain pattern:
+
+ while (<>) {
+ study;
+ print ".IX foo\n" if /\bfoo\b/;
+ print ".IX bar\n" if /\bbar\b/;
+ print ".IX blurfl\n" if /\bblurfl\b/;
+ # ...
+ print;
+ }
+
+In searching for C</\bfoo\b/>, only locations in C<$_> that contain C<f>
+will be looked at, because C<f> is rarer than C<o>. In general, this is
+a big win except in pathological cases. The only question is whether
+it saves you more time than it took to build the linked list in the
+first place.
+
+Note that if you have to look for strings that you don't know till
+runtime, you can build an entire loop as a string and C<eval> that to
+avoid recompiling all your patterns all the time. Together with
+undefining C<$/> to input entire files as one record, this can be quite
+fast, often faster than specialized programs like fgrep(1). The following
+scans a list of files (C<@files>) for a list of words (C<@words>), and prints
+out the names of those files that contain a match:
+
+ $search = 'while (<>) { study;';
+ foreach $word (@words) {
+ $search .= "++\$seen{\$ARGV} if /\\b$word\\b/;\n";
+ }
+ $search .= "}";
+ @ARGV = @files;
+ undef $/;
+ eval $search; # this screams
+ $/ = "\n"; # put back to normal input delimiter
+ foreach $file (sort keys(%seen)) {
+ print $file, "\n";
+ }
+
+=item sub NAME BLOCK
+X<sub>
+
+=item sub NAME (PROTO) BLOCK
+
+=item sub NAME : ATTRS BLOCK
+
+=item sub NAME (PROTO) : ATTRS BLOCK
+
+This is subroutine definition, not a real function I<per se>.
+Without a BLOCK it's just a forward declaration. Without a NAME,
+it's an anonymous function declaration, and does actually return
+a value: the CODE ref of the closure you just created.
+
+See L<perlsub> and L<perlref> for details about subroutines and
+references, and L<attributes> and L<Attribute::Handlers> for more
+information about attributes.
+
+=item substr EXPR,OFFSET,LENGTH,REPLACEMENT
+X<substr> X<substring> X<mid> X<left> X<right>
+
+=item substr EXPR,OFFSET,LENGTH
+
+=item substr EXPR,OFFSET
+
+Extracts a substring out of EXPR and returns it. First character is at
+offset C<0>, or whatever you've set C<$[> to (but don't do that).
+If OFFSET is negative (or more precisely, less than C<$[>), starts
+that far from the end of the string. If LENGTH is omitted, returns
+everything to the end of the string. If LENGTH is negative, leaves that
+many characters off the end of the string.
+
+ my $s = "The black cat climbed the green tree";
+ my $color = substr $s, 4, 5; # black
+ my $middle = substr $s, 4, -11; # black cat climbed the
+ my $end = substr $s, 14; # climbed the green tree
+ my $tail = substr $s, -4; # tree
+ my $z = substr $s, -4, 2; # tr
+
+You can use the substr() function as an lvalue, in which case EXPR
+must itself be an lvalue. If you assign something shorter than LENGTH,
+the string will shrink, and if you assign something longer than LENGTH,
+the string will grow to accommodate it. To keep the string the same
+length, you may need to pad or chop your value using C<sprintf>.
+
+If OFFSET and LENGTH specify a substring that is partly outside the
+string, only the part within the string is returned. If the substring
+is beyond either end of the string, substr() returns the undefined
+value and produces a warning. When used as an lvalue, specifying a
+substring that is entirely outside the string raises an exception.
+Here's an example showing the behavior for boundary cases:
+
+ my $name = 'fred';
+ substr($name, 4) = 'dy'; # $name is now 'freddy'
+ my $null = substr $name, 6, 2; # returns "" (no warning)
+ my $oops = substr $name, 7; # returns undef, with warning
+ substr($name, 7) = 'gap'; # raises an exception
+
+An alternative to using substr() as an lvalue is to specify the
+replacement string as the 4th argument. This allows you to replace
+parts of the EXPR and return what was there before in one operation,
+just as you can with splice().
+
+ my $s = "The black cat climbed the green tree";
+ my $z = substr $s, 14, 7, "jumped from"; # climbed
+ # $s is now "The black cat jumped from the green tree"
+
+Note that the lvalue returned by the 3-arg version of substr() acts as
+a 'magic bullet'; each time it is assigned to, it remembers which part
+of the original string is being modified; for example:
+
+ $x = '1234';
+ for (substr($x,1,2)) {
+ $_ = 'a'; print $x,"\n"; # prints 1a4
+ $_ = 'xyz'; print $x,"\n"; # prints 1xyz4
+ $x = '56789';
+ $_ = 'pq'; print $x,"\n"; # prints 5pq9
+ }
+
+Prior to Perl version 5.9.1, the result of using an lvalue multiple times was
+unspecified.
+
+=item symlink OLDFILE,NEWFILE
+X<symlink> X<link> X<symbolic link> X<link, symbolic>
+
+Creates a new filename symbolically linked to the old filename.
+Returns C<1> for success, C<0> otherwise. On systems that don't support
+symbolic links, raises an exception. To check for that,
+use eval:
+
+ $symlink_exists = eval { symlink("",""); 1 };
+
+=item syscall NUMBER, LIST
+X<syscall> X<system call>
+
+Calls the system call specified as the first element of the list,
+passing the remaining elements as arguments to the system call. If
+unimplemented, raises an exception. The arguments are interpreted
+as follows: if a given argument is numeric, the argument is passed as
+an int. If not, the pointer to the string value is passed. You are
+responsible to make sure a string is pre-extended long enough to
+receive any result that might be written into a string. You can't use a
+string literal (or other read-only string) as an argument to C<syscall>
+because Perl has to assume that any string pointer might be written
+through. If your
+integer arguments are not literals and have never been interpreted in a
+numeric context, you may need to add C<0> to them to force them to look
+like numbers. This emulates the C<syswrite> function (or vice versa):
+
+ require 'syscall.ph'; # may need to run h2ph
+ $s = "hi there\n";
+ syscall(&SYS_write, fileno(STDOUT), $s, length $s);
+
+Note that Perl supports passing of up to only 14 arguments to your syscall,
+which in practice should (usually) suffice.
+
+Syscall returns whatever value returned by the system call it calls.
+If the system call fails, C<syscall> returns C<-1> and sets C<$!> (errno).
+Note that some system calls can legitimately return C<-1>. The proper
+way to handle such calls is to assign C<$!=0;> before the call and
+check the value of C<$!> if syscall returns C<-1>.
+
+There's a problem with C<syscall(&SYS_pipe)>: it returns the file
+number of the read end of the pipe it creates. There is no way
+to retrieve the file number of the other end. You can avoid this
+problem by using C<pipe> instead.
+
+=item sysopen FILEHANDLE,FILENAME,MODE
+X<sysopen>
+
+=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
+
+Opens the file whose filename is given by FILENAME, and associates it
+with FILEHANDLE. If FILEHANDLE is an expression, its value is used as
+the name of the real filehandle wanted. This function calls the
+underlying operating system's C<open> function with the parameters
+FILENAME, MODE, PERMS.
+
+The possible values and flag bits of the MODE parameter are
+system-dependent; they are available via the standard module C<Fcntl>.
+See the documentation of your operating system's C<open> to see which
+values and flag bits are available. You may combine several flags
+using the C<|>-operator.
+
+Some of the most common values are C<O_RDONLY> for opening the file in
+read-only mode, C<O_WRONLY> for opening the file in write-only mode,
+and C<O_RDWR> for opening the file in read-write mode.
+X<O_RDONLY> X<O_RDWR> X<O_WRONLY>
+
+For historical reasons, some values work on almost every system
+supported by Perl: 0 means read-only, 1 means write-only, and 2
+means read/write. We know that these values do I<not> work under
+OS/390 & VM/ESA Unix and on the Macintosh; you probably don't want to
+use them in new code.
+
+If the file named by FILENAME does not exist and the C<open> call creates
+it (typically because MODE includes the C<O_CREAT> flag), then the value of
+PERMS specifies the permissions of the newly created file. If you omit
+the PERMS argument to C<sysopen>, Perl uses the octal value C<0666>.
+These permission values need to be in octal, and are modified by your
+process's current C<umask>.
+X<O_CREAT>
+
+In many systems the C<O_EXCL> flag is available for opening files in
+exclusive mode. This is B<not> locking: exclusiveness means here that
+if the file already exists, sysopen() fails. C<O_EXCL> may not work
+on network filesystems, and has no effect unless the C<O_CREAT> flag
+is set as well. Setting C<O_CREAT|O_EXCL> prevents the file from
+being opened if it is a symbolic link. It does not protect against
+symbolic links in the file's path.
+X<O_EXCL>
+
+Sometimes you may want to truncate an already-existing file. This
+can be done using the C<O_TRUNC> flag. The behavior of
+C<O_TRUNC> with C<O_RDONLY> is undefined.
+X<O_TRUNC>
+
+You should seldom if ever use C<0644> as argument to C<sysopen>, because
+that takes away the user's option to have a more permissive umask.
+Better to omit it. See the perlfunc(1) entry on C<umask> for more
+on this.
+
+Note that C<sysopen> depends on the fdopen() C library function.
+On many Unix systems, fdopen() is known to fail when file descriptors
+exceed a certain value, typically 255. If you need more file
+descriptors than that, consider rebuilding Perl to use the C<sfio>
+library, or perhaps using the POSIX::open() function.
+
+See L<perlopentut> for a kinder, gentler explanation of opening files.
+
+=item sysread FILEHANDLE,SCALAR,LENGTH,OFFSET
+X<sysread>
+
+=item sysread FILEHANDLE,SCALAR,LENGTH
+
+Attempts to read LENGTH bytes of data into variable SCALAR from the
+specified FILEHANDLE, using the read(2). It bypasses
+buffered IO, so mixing this with other kinds of reads, C<print>,
+C<write>, C<seek>, C<tell>, or C<eof> can cause confusion because the
+perlio or stdio layers usually buffers data. Returns the number of
+bytes actually read, C<0> at end of file, or undef if there was an
+error (in the latter case C<$!> is also set). SCALAR will be grown or
+shrunk so that the last byte actually read is the last byte of the
+scalar after the read.
+
+An OFFSET may be specified to place the read data at some place in the
+string other than the beginning. A negative OFFSET specifies
+placement at that many characters counting backwards from the end of
+the string. A positive OFFSET greater than the length of SCALAR
+results in the string being padded to the required size with C<"\0">
+bytes before the result of the read is appended.
+
+There is no syseof() function, which is ok, since eof() doesn't work
+well on device files (like ttys) anyway. Use sysread() and check
+for a return value for 0 to decide whether you're done.
+
+Note that if the filehandle has been marked as C<:utf8> Unicode
+characters are read instead of bytes (the LENGTH, OFFSET, and the
+return value of sysread() are in Unicode characters).
+The C<:encoding(...)> layer implicitly introduces the C<:utf8> layer.
+See L</binmode>, L</open>, and the C<open> pragma, L<open>.
+
+=item sysseek FILEHANDLE,POSITION,WHENCE
+X<sysseek> X<lseek>
+
+Sets FILEHANDLE's system position in bytes using
+lseek(2). FILEHANDLE may be an expression whose value gives the name
+of the filehandle. The values for WHENCE are C<0> to set the new
+position to POSITION, C<1> to set the it to the current position plus
+POSITION, and C<2> to set it to EOF plus POSITION (typically
+negative).
+
+Note the I<in bytes>: even if the filehandle has been set to operate
+on characters (for example by using the C<:encoding(utf8)> I/O layer),
+tell() will return byte offsets, not character offsets (because
+implementing that would render sysseek() unacceptably slow).
+
+sysseek() bypasses normal buffered IO, so mixing this with reads (other
+than C<sysread>, for example C<< <> >> or read()) C<print>, C<write>,
+C<seek>, C<tell>, or C<eof> may cause confusion.
+
+For WHENCE, you may also use the constants C<SEEK_SET>, C<SEEK_CUR>,
+and C<SEEK_END> (start of the file, current position, end of the file)
+from the Fcntl module. Use of the constants is also more portable
+than relying on 0, 1, and 2. For example to define a "systell" function:
+
+ use Fcntl 'SEEK_CUR';
+ sub systell { sysseek($_[0], 0, SEEK_CUR) }
+
+Returns the new position, or the undefined value on failure. A position
+of zero is returned as the string C<"0 but true">; thus C<sysseek> returns
+true on success and false on failure, yet you can still easily determine
+the new position.
+
+=item system LIST
+X<system> X<shell>
+
+=item system PROGRAM LIST
+
+Does exactly the same thing as C<exec LIST>, except that a fork is
+done first, and the parent process waits for the child process to
+exit. Note that argument processing varies depending on the
+number of arguments. If there is more than one argument in LIST,
+or if LIST is an array with more than one value, starts the program
+given by the first element of the list with arguments given by the
+rest of the list. If there is only one scalar argument, the argument
+is checked for shell metacharacters, and if there are any, the
+entire argument is passed to the system's command shell for parsing
+(this is C</bin/sh -c> on Unix platforms, but varies on other
+platforms). If there are no shell metacharacters in the argument,
+it is split into words and passed directly to C<execvp>, which is
+more efficient.
+
+Beginning with v5.6.0, Perl will attempt to flush all files opened for
+output before any operation that may do a fork, but this may not be
+supported on some platforms (see L<perlport>). To be safe, you may need
+to set C<$|> ($AUTOFLUSH in English) or call the C<autoflush()> method
+of C<IO::Handle> on any open handles.
+
+The return value is the exit status of the program as returned by the
+C<wait> call. To get the actual exit value, shift right by eight (see
+below). See also L</exec>. This is I<not> what you want to use to capture
+the output from a command, for that you should use merely backticks or
+C<qx//>, as described in L<perlop/"`STRING`">. Return value of -1
+indicates a failure to start the program or an error of the wait(2) system
+call (inspect $! for the reason).
+
+If you'd like to make C<system> (and many other bits of Perl) die on error,
+have a look at the L<autodie> pragma.
+
+Like C<exec>, C<system> allows you to lie to a program about its name if
+you use the C<system PROGRAM LIST> syntax. Again, see L</exec>.
+
+Since C<SIGINT> and C<SIGQUIT> are ignored during the execution of
+C<system>, if you expect your program to terminate on receipt of these
+signals you will need to arrange to do so yourself based on the return
+value.
+
+ @args = ("command", "arg1", "arg2");
+ system(@args) == 0
+ or die "system @args failed: $?"
+
+If you'd like to manually inspect C<system>'s failure, you can check all
+possible failure modes by inspecting C<$?> like this:
+
+ if ($? == -1) {
+ print "failed to execute: $!\n";
+ }
+ elsif ($? & 127) {
+ printf "child died with signal %d, %s coredump\n",
+ ($? & 127), ($? & 128) ? 'with' : 'without';
+ }
+ else {
+ printf "child exited with value %d\n", $? >> 8;
+ }
+
+Alternatively, you may inspect the value of C<${^CHILD_ERROR_NATIVE}>
+with the C<W*()> calls from the POSIX module.
+
+When C<system>'s arguments are executed indirectly by the shell,
+results and return codes are subject to its quirks.
+See L<perlop/"`STRING`"> and L</exec> for details.
+
+Since C<system> does a C<fork> and C<wait> it may affect a C<SIGCHLD>
+handler. See L<perlipc> for details.
+
+=item syswrite FILEHANDLE,SCALAR,LENGTH,OFFSET
+X<syswrite>
+
+=item syswrite FILEHANDLE,SCALAR,LENGTH
+
+=item syswrite FILEHANDLE,SCALAR
+
+Attempts to write LENGTH bytes of data from variable SCALAR to the
+specified FILEHANDLE, using write(2). If LENGTH is
+not specified, writes whole SCALAR. It bypasses buffered IO, so
+mixing this with reads (other than C<sysread())>, C<print>, C<write>,
+C<seek>, C<tell>, or C<eof> may cause confusion because the perlio and
+stdio layers usually buffers data. Returns the number of bytes
+actually written, or C<undef> if there was an error (in this case the
+errno variable C<$!> is also set). If the LENGTH is greater than the
+data available in the SCALAR after the OFFSET, only as much data as is
+available will be written.
+
+An OFFSET may be specified to write the data from some part of the
+string other than the beginning. A negative OFFSET specifies writing
+that many characters counting backwards from the end of the string.
+If SCALAR is of length zero, you can only use an OFFSET of 0.
+
+B<Warning>: If the filehandle is marked C<:utf8>, Unicode characters
+encoded in UTF-8 are written instead of bytes, and the LENGTH, OFFSET, and
+return value of syswrite() are in (UTF-8 encoded Unicode) characters.
+The C<:encoding(...)> layer implicitly introduces the C<:utf8> layer.
+See L</binmode>, L</open>, and the C<open> pragma, L<open>.
+
+=item tell FILEHANDLE
+X<tell>
+
+=item tell
+
+Returns the current position I<in bytes> for FILEHANDLE, or -1 on
+error. FILEHANDLE may be an expression whose value gives the name of
+the actual filehandle. If FILEHANDLE is omitted, assumes the file
+last read.
+
+Note the I<in bytes>: even if the filehandle has been set to
+operate on characters (for example by using the C<:encoding(utf8)> open
+layer), tell() will return byte offsets, not character offsets (because
+that would render seek() and tell() rather slow).
+
+The return value of tell() for the standard streams like the STDIN
+depends on the operating system: it may return -1 or something else.
+tell() on pipes, fifos, and sockets usually returns -1.
+
+There is no C<systell> function. Use C<sysseek(FH, 0, 1)> for that.
+
+Do not use tell() (or other buffered I/O operations) on a filehandle
+that has been manipulated by sysread(), syswrite() or sysseek().
+Those functions ignore the buffering, while tell() does not.
+
+=item telldir DIRHANDLE
+X<telldir>
+
+Returns the current position of the C<readdir> routines on DIRHANDLE.
+Value may be given to C<seekdir> to access a particular location in a
+directory. C<telldir> has the same caveats about possible directory
+compaction as the corresponding system library routine.
+
+=item tie VARIABLE,CLASSNAME,LIST
+X<tie>
+
+This function binds a variable to a package class that will provide the
+implementation for the variable. VARIABLE is the name of the variable
+to be enchanted. CLASSNAME is the name of a class implementing objects
+of correct type. Any additional arguments are passed to the C<new>
+method of the class (meaning C<TIESCALAR>, C<TIEHANDLE>, C<TIEARRAY>,
+or C<TIEHASH>). Typically these are arguments such as might be passed
+to the C<dbm_open()> function of C. The object returned by the C<new>
+method is also returned by the C<tie> function, which would be useful
+if you want to access other methods in CLASSNAME.
+
+Note that functions such as C<keys> and C<values> may return huge lists
+when used on large objects, like DBM files. You may prefer to use the
+C<each> function to iterate over such. Example:
+
+ # print out history file offsets
+ use NDBM_File;
+ tie(%HIST, 'NDBM_File', '/usr/lib/news/history', 1, 0);
+ while (($key,$val) = each %HIST) {
+ print $key, ' = ', unpack('L',$val), "\n";
+ }
+ untie(%HIST);
+
+A class implementing a hash should have the following methods:
+
+ TIEHASH classname, LIST
+ FETCH this, key
+ STORE this, key, value
+ DELETE this, key
+ CLEAR this
+ EXISTS this, key
+ FIRSTKEY this
+ NEXTKEY this, lastkey
+ SCALAR this
+ DESTROY this
+ UNTIE this
+
+A class implementing an ordinary array should have the following methods:
+
+ TIEARRAY classname, LIST
+ FETCH this, key
+ STORE this, key, value
+ FETCHSIZE this
+ STORESIZE this, count
+ CLEAR this
+ PUSH this, LIST
+ POP this
+ SHIFT this
+ UNSHIFT this, LIST
+ SPLICE this, offset, length, LIST
+ EXTEND this, count
+ DESTROY this
+ UNTIE this
+
+A class implementing a filehandle should have the following methods:
+
+ TIEHANDLE classname, LIST
+ READ this, scalar, length, offset
+ READLINE this
+ GETC this
+ WRITE this, scalar, length, offset
+ PRINT this, LIST
+ PRINTF this, format, LIST
+ BINMODE this
+ EOF this
+ FILENO this
+ SEEK this, position, whence
+ TELL this
+ OPEN this, mode, LIST
+ CLOSE this
+ DESTROY this
+ UNTIE this
+
+A class implementing a scalar should have the following methods:
+
+ TIESCALAR classname, LIST
+ FETCH this,
+ STORE this, value
+ DESTROY this
+ UNTIE this
+
+Not all methods indicated above need be implemented. See L<perltie>,
+L<Tie::Hash>, L<Tie::Array>, L<Tie::Scalar>, and L<Tie::Handle>.
+
+Unlike C<dbmopen>, the C<tie> function will not C<use> or C<require> a module
+for you; you need to do that explicitly yourself. See L<DB_File>
+or the F<Config> module for interesting C<tie> implementations.
+
+For further details see L<perltie>, L<"tied VARIABLE">.
+
+=item tied VARIABLE
+X<tied>
+
+Returns a reference to the object underlying VARIABLE (the same value
+that was originally returned by the C<tie> call that bound the variable
+to a package.) Returns the undefined value if VARIABLE isn't tied to a
+package.
+
+=item time
+X<time> X<epoch>
+
+Returns the number of non-leap seconds since whatever time the system
+considers to be the epoch, suitable for feeding to C<gmtime> and
+C<localtime>. On most systems the epoch is 00:00:00 UTC, January 1, 1970;
+a prominent exception being Mac OS Classic which uses 00:00:00, January 1,
+1904 in the current local time zone for its epoch.
+
+For measuring time in better granularity than one second,
+you may use either the L<Time::HiRes> module (from CPAN, and starting from
+Perl 5.8 part of the standard distribution), or if you have
+gettimeofday(2), you may be able to use the C<syscall> interface of Perl.
+See L<perlfaq8> for details.
+
+For date and time processing look at the many related modules on CPAN.
+For a comprehensive date and time representation look at the
+L<DateTime> module.
+
+=item times
+X<times>
+
+Returns a four-element list giving the user and system times, in
+seconds, for this process and the children of this process.
+
+ ($user,$system,$cuser,$csystem) = times;
+
+In scalar context, C<times> returns C<$user>.
+
+Children's times are only included for terminated children.
+
+=item tr///
+
+The transliteration operator. Same as C<y///>. See
+L<perlop/"Quote and Quote-like Operators">.
+
+=item truncate FILEHANDLE,LENGTH
+X<truncate>
+
+=item truncate EXPR,LENGTH
+
+Truncates the file opened on FILEHANDLE, or named by EXPR, to the
+specified length. Raises an exception if truncate isn't implemented
+on your system. Returns true if successful, the undefined value
+otherwise.
+
+The behavior is undefined if LENGTH is greater than the length of the
+file.
+
+The position in the file of FILEHANDLE is left unchanged. You may want to
+call L<seek> before writing to the file.
+
+=item uc EXPR
+X<uc> X<uppercase> X<toupper>
+
+=item uc
+
+Returns an uppercased version of EXPR. This is the internal function
+implementing the C<\U> escape in double-quoted strings.
+It does not attempt to do titlecase mapping on initial letters. See
+L</ucfirst> for that.
+
+If EXPR is omitted, uses C<$_>.
+
+This function behaves the same way under various pragma, such as in a locale,
+as L</lc> does.
+
+=item ucfirst EXPR
+X<ucfirst> X<uppercase>
+
+=item ucfirst
+
+Returns the value of EXPR with the first character in uppercase
+(titlecase in Unicode). This is the internal function implementing
+the C<\u> escape in double-quoted strings.
+
+If EXPR is omitted, uses C<$_>.
+
+This function behaves the same way under various pragma, such as in a locale,
+as L</lc> does.
+
+=item umask EXPR
+X<umask>
+
+=item umask
+
+Sets the umask for the process to EXPR and returns the previous value.
+If EXPR is omitted, merely returns the current umask.
+
+The Unix permission C<rwxr-x---> is represented as three sets of three
+bits, or three octal digits: C<0750> (the leading 0 indicates octal
+and isn't one of the digits). The C<umask> value is such a number
+representing disabled permissions bits. The permission (or "mode")
+values you pass C<mkdir> or C<sysopen> are modified by your umask, so
+even if you tell C<sysopen> to create a file with permissions C<0777>,
+if your umask is C<0022> then the file will actually be created with
+permissions C<0755>. If your C<umask> were C<0027> (group can't
+write; others can't read, write, or execute), then passing
+C<sysopen> C<0666> would create a file with mode C<0640> (C<0666 &~
+027> is C<0640>).
+
+Here's some advice: supply a creation mode of C<0666> for regular
+files (in C<sysopen>) and one of C<0777> for directories (in
+C<mkdir>) and executable files. This gives users the freedom of
+choice: if they want protected files, they might choose process umasks
+of C<022>, C<027>, or even the particularly antisocial mask of C<077>.
+Programs should rarely if ever make policy decisions better left to
+the user. The exception to this is when writing files that should be
+kept private: mail files, web browser cookies, I<.rhosts> files, and
+so on.
+
+If umask(2) is not implemented on your system and you are trying to
+restrict access for I<yourself> (i.e., C<< (EXPR & 0700) > 0 >>),
+raises an exception. If umask(2) is not implemented and you are
+not trying to restrict access for yourself, returns C<undef>.
+
+Remember that a umask is a number, usually given in octal; it is I<not> a
+string of octal digits. See also L</oct>, if all you have is a string.
+
+=item undef EXPR
+X<undef> X<undefine>
+
+=item undef
+
+Undefines the value of EXPR, which must be an lvalue. Use only on a
+scalar value, an array (using C<@>), a hash (using C<%>), a subroutine
+(using C<&>), or a typeglob (using C<*>). Saying C<undef $hash{$key}>
+will probably not do what you expect on most predefined variables or
+DBM list values, so don't do that; see L<delete>. Always returns the
+undefined value. You can omit the EXPR, in which case nothing is
+undefined, but you still get an undefined value that you could, for
+instance, return from a subroutine, assign to a variable, or pass as a
+parameter. Examples:
+
+ undef $foo;
+ undef $bar{'blurfl'}; # Compare to: delete $bar{'blurfl'};
+ undef @ary;
+ undef %hash;
+ undef &mysub;
+ undef *xyz; # destroys $xyz, @xyz, %xyz, &xyz, etc.
+ return (wantarray ? (undef, $errmsg) : undef) if $they_blew_it;
+ select undef, undef, undef, 0.25;
+ ($a, $b, undef, $c) = &foo; # Ignore third value returned
+
+Note that this is a unary operator, not a list operator.
+
+=item unlink LIST
+X<unlink> X<delete> X<remove> X<rm> X<del>
+
+=item unlink
+
+Deletes a list of files. On success, it returns the number of files
+it successfully deleted. On failure, it returns false and sets C<$!>
+(errno):
+
+ my $unlinked = unlink 'a', 'b', 'c';
+ unlink @goners;
+ unlink glob "*.bak";
+
+On error, C<unlink> will not tell you which files it could not remove.
+If you want to know which files you could not remove, try them one
+at a time:
+
+ foreach my $file ( @goners ) {
+ unlink $file or warn "Could not unlink $file: $!";
+ }
+
+Note: C<unlink> will not attempt to delete directories unless you are
+superuser and the B<-U> flag is supplied to Perl. Even if these
+conditions are met, be warned that unlinking a directory can inflict
+damage on your filesystem. Finally, using C<unlink> on directories is
+not supported on many operating systems. Use C<rmdir> instead.
+
+If LIST is omitted, C<unlink> uses C<$_>.
+
+=item unpack TEMPLATE,EXPR
+X<unpack>
+
+=item unpack TEMPLATE
+
+C<unpack> does the reverse of C<pack>: it takes a string
+and expands it out into a list of values.
+(In scalar context, it returns merely the first value produced.)
+
+If EXPR is omitted, unpacks the C<$_> string.
+See L<perlpacktut> for an introduction to this function.
+
+The string is broken into chunks described by the TEMPLATE. Each chunk
+is converted separately to a value. Typically, either the string is a result
+of C<pack>, or the characters of the string represent a C structure of some
+kind.
+
+The TEMPLATE has the same format as in the C<pack> function.
+Here's a subroutine that does substring:
+
+ sub substr {
+ my($what,$where,$howmuch) = @_;
+ unpack("x$where a$howmuch", $what);
+ }
+
+and then there's
+
+ sub ordinal { unpack("W",$_[0]); } # same as ord()
+
+In addition to fields allowed in pack(), you may prefix a field with
+a %<number> to indicate that
+you want a <number>-bit checksum of the items instead of the items
+themselves. Default is a 16-bit checksum. Checksum is calculated by
+summing numeric values of expanded values (for string fields the sum of
+C<ord($char)> is taken, for bit fields the sum of zeroes and ones).
+
+For example, the following
+computes the same number as the System V sum program:
+
+ $checksum = do {
+ local $/; # slurp!
+ unpack("%32W*",<>) % 65535;
+ };
+
+The following efficiently counts the number of set bits in a bit vector:
+
+ $setbits = unpack("%32b*", $selectmask);
+
+The C<p> and C<P> formats should be used with care. Since Perl
+has no way of checking whether the value passed to C<unpack()>
+corresponds to a valid memory location, passing a pointer value that's
+not known to be valid is likely to have disastrous consequences.
+
+If there are more pack codes or if the repeat count of a field or a group
+is larger than what the remainder of the input string allows, the result
+is not well defined: the repeat count may be decreased, or
+C<unpack()> may produce empty strings or zeros, or it may raise an exception.
+If the input string is longer than one described by the TEMPLATE,
+the remainder of that input string is ignored.
+
+See L</pack> for more examples and notes.
+
+=item untie VARIABLE
+X<untie>
+
+Breaks the binding between a variable and a package. (See C<tie>.)
+Has no effect if the variable is not tied.
+
+=item unshift ARRAY,LIST
+X<unshift>
+
+Does the opposite of a C<shift>. Or the opposite of a C<push>,
+depending on how you look at it. Prepends list to the front of the
+array, and returns the new number of elements in the array.
+
+ unshift(@ARGV, '-e') unless $ARGV[0] =~ /^-/;
+
+Note the LIST is prepended whole, not one element at a time, so the
+prepended elements stay in the same order. Use C<reverse> to do the
+reverse.
+
+=item use Module VERSION LIST
+X<use> X<module> X<import>
+
+=item use Module VERSION
+
+=item use Module LIST
+
+=item use Module
+
+=item use VERSION
+
+Imports some semantics into the current package from the named module,
+generally by aliasing certain subroutine or variable names into your
+package. It is exactly equivalent to
+
+ BEGIN { require Module; Module->import( LIST ); }
+
+except that Module I<must> be a bareword.
+
+In the peculiar C<use VERSION> form, VERSION may be either a positive
+decimal fraction such as 5.006, which will be compared to C<$]>, or a v-string
+of the form v5.6.1, which will be compared to C<$^V> (aka $PERL_VERSION). An
+exception is raised if VERSION is greater than the version of the
+current Perl interpreter; Perl will not attempt to parse the rest of the
+file. Compare with L</require>, which can do a similar check at run time.
+Symmetrically, C<no VERSION> allows you to specify that you want a version
+of Perl older than the specified one.
+
+Specifying VERSION as a literal of the form v5.6.1 should generally be
+avoided, because it leads to misleading error messages under earlier
+versions of Perl (that is, prior to 5.6.0) that do not support this
+syntax. The equivalent numeric version should be used instead.
+
+ use v5.6.1; # compile time version check
+ use 5.6.1; # ditto
+ use 5.006_001; # ditto; preferred for backwards compatibility
+
+This is often useful if you need to check the current Perl version before
+C<use>ing library modules that won't work with older versions of Perl.
+(We try not to do this more than we have to.)
+
+Also, if the specified Perl version is greater than or equal to 5.9.5,
+C<use VERSION> will also load the C<feature> pragma and enable all
+features available in the requested version. See L<feature>.
+Similarly, if the specified Perl version is greater than or equal to
+5.11.0, strictures are enabled lexically as with C<use strict> (except
+that the F<strict.pm> file is not actually loaded).
+
+The C<BEGIN> forces the C<require> and C<import> to happen at compile time. The
+C<require> makes sure the module is loaded into memory if it hasn't been
+yet. The C<import> is not a builtin; it's just an ordinary static method
+call into the C<Module> package to tell the module to import the list of
+features back into the current package. The module can implement its
+C<import> method any way it likes, though most modules just choose to
+derive their C<import> method via inheritance from the C<Exporter> class that
+is defined in the C<Exporter> module. See L<Exporter>. If no C<import>
+method can be found then the call is skipped, even if there is an AUTOLOAD
+method.
+
+If you do not want to call the package's C<import> method (for instance,
+to stop your namespace from being altered), explicitly supply the empty list:
+
+ use Module ();
+
+That is exactly equivalent to
+
+ BEGIN { require Module }
+
+If the VERSION argument is present between Module and LIST, then the
+C<use> will call the VERSION method in class Module with the given
+version as an argument. The default VERSION method, inherited from
+the UNIVERSAL class, croaks if the given version is larger than the
+value of the variable C<$Module::VERSION>.
+
+Again, there is a distinction between omitting LIST (C<import> called
+with no arguments) and an explicit empty LIST C<()> (C<import> not
+called). Note that there is no comma after VERSION!
+
+Because this is a wide-open interface, pragmas (compiler directives)
+are also implemented this way. Currently implemented pragmas are:
+
+ use constant;
+ use diagnostics;
+ use integer;
+ use sigtrap qw(SEGV BUS);
+ use strict qw(subs vars refs);
+ use subs qw(afunc blurfl);
+ use warnings qw(all);
+ use sort qw(stable _quicksort _mergesort);
+
+Some of these pseudo-modules import semantics into the current
+block scope (like C<strict> or C<integer>, unlike ordinary modules,
+which import symbols into the current package (which are effective
+through the end of the file).
+
+Because C<use> takes effect at compile time, it doesn't respect the
+ordinary flow control of the code being compiled. In particular, putting
+a C<use> inside the false branch of a conditional doesn't prevent it
+from being processed. If a module or pragma only needs to be loaded
+conditionally, this can be done using the L<if> pragma:
+
+ use if $] < 5.008, "utf8";
+ use if WANT_WARNINGS, warnings => qw(all);
+
+There's a corresponding C<no> command that unimports meanings imported
+by C<use>, i.e., it calls C<unimport Module LIST> instead of C<import>.
+It behaves just as C<import> does with VERSION, an omitted or empty LIST,
+or no unimport method being found.
+
+ no integer;
+ no strict 'refs';
+ no warnings;
+
+Care should be taken when using the C<no VERSION> form of C<no>. It is
+I<only> meant to be used to assert that the running perl is of a earlier
+version than its argument and I<not> to undo the feature-enabling side effects
+of C<use VERSION>.
+
+See L<perlmodlib> for a list of standard modules and pragmas. See L<perlrun>
+for the C<-M> and C<-m> command-line options to Perl that give C<use>
+functionality from the command-line.
+
+=item utime LIST
+X<utime>
+
+Changes the access and modification times on each file of a list of
+files. The first two elements of the list must be the NUMERICAL access
+and modification times, in that order. Returns the number of files
+successfully changed. The inode change time of each file is set
+to the current time. For example, this code has the same effect as the
+Unix touch(1) command when the files I<already exist> and belong to
+the user running the program:
+
+ #!/usr/bin/perl
+ $atime = $mtime = time;
+ utime $atime, $mtime, @ARGV;
+
+Since Perl 5.7.2, if the first two elements of the list are C<undef>,
+the utime(2) syscall from your C library is called with a null second
+argument. On most systems, this will set the file's access and
+modification times to the current time (i.e., equivalent to the example
+above) and will work even on files you don't own provided you have write
+permission:
+
+ for $file (@ARGV) {
+ utime(undef, undef, $file)
+ || warn "couldn't touch $file: $!";
+ }
+
+Under NFS this will use the time of the NFS server, not the time of
+the local machine. If there is a time synchronization problem, the
+NFS server and local machine will have different times. The Unix
+touch(1) command will in fact normally use this form instead of the
+one shown in the first example.
+
+Passing only one of the first two elements as C<undef> is
+equivalent to passing a 0 and will not have the effect
+described when both are C<undef>. This also triggers an
+uninitialized warning.
+
+On systems that support futimes(2), you may pass filehandles among the
+files. On systems that don't support futimes(2), passing filehandles raises
+an exception. Filehandles must be passed as globs or glob references to be
+recognized; barewords are considered filenames.
+
+=item values HASH
+X<values>
+
+=item values ARRAY
+
+Returns a list consisting of all the values of the named hash, or the values
+of an array. (In a scalar context, returns the number of values.)
+
+The values are returned in an apparently random order. The actual
+random order is subject to change in future versions of Perl, but it
+is guaranteed to be the same order as either the C<keys> or C<each>
+function would produce on the same (unmodified) hash. Since Perl
+5.8.1 the ordering is different even between different runs of Perl
+for security reasons (see L<perlsec/"Algorithmic Complexity Attacks">).
+
+As a side effect, calling values() resets the HASH or ARRAY's internal
+iterator,
+see L</each>. (In particular, calling values() in void context resets
+the iterator with no other overhead. Apart from resetting the iterator,
+C<values @array> in list context is the same as plain C<@array>.
+We recommend that you use void context C<keys @array> for this, but reasoned
+that it taking C<values @array> out would require more documentation than
+leaving it in.)
+
+
+Note that the values are not copied, which means modifying them will
+modify the contents of the hash:
+
+ for (values %hash) { s/foo/bar/g } # modifies %hash values
+ for (@hash{keys %hash}) { s/foo/bar/g } # same
+
+See also C<keys>, C<each>, and C<sort>.
+
+=item vec EXPR,OFFSET,BITS
+X<vec> X<bit> X<bit vector>
+
+Treats the string in EXPR as a bit vector made up of elements of
+width BITS, and returns the value of the element specified by OFFSET
+as an unsigned integer. BITS therefore specifies the number of bits
+that are reserved for each element in the bit vector. This must
+be a power of two from 1 to 32 (or 64, if your platform supports
+that).
+
+If BITS is 8, "elements" coincide with bytes of the input string.
+
+If BITS is 16 or more, bytes of the input string are grouped into chunks
+of size BITS/8, and each group is converted to a number as with
+pack()/unpack() with big-endian formats C<n>/C<N> (and analogously
+for BITS==64). See L<"pack"> for details.
+
+If bits is 4 or less, the string is broken into bytes, then the bits
+of each byte are broken into 8/BITS groups. Bits of a byte are
+numbered in a little-endian-ish way, as in C<0x01>, C<0x02>,
+C<0x04>, C<0x08>, C<0x10>, C<0x20>, C<0x40>, C<0x80>. For example,
+breaking the single input byte C<chr(0x36)> into two groups gives a list
+C<(0x6, 0x3)>; breaking it into 4 groups gives C<(0x2, 0x1, 0x3, 0x0)>.
+
+C<vec> may also be assigned to, in which case parentheses are needed
+to give the expression the correct precedence as in
+
+ vec($image, $max_x * $x + $y, 8) = 3;
+
+If the selected element is outside the string, the value 0 is returned.
+If an element off the end of the string is written to, Perl will first
+extend the string with sufficiently many zero bytes. It is an error
+to try to write off the beginning of the string (i.e., negative OFFSET).
+
+If the string happens to be encoded as UTF-8 internally (and thus has
+the UTF8 flag set), this is ignored by C<vec>, and it operates on the
+internal byte string, not the conceptual character string, even if you
+only have characters with values less than 256.
+
+Strings created with C<vec> can also be manipulated with the logical
+operators C<|>, C<&>, C<^>, and C<~>. These operators will assume a bit
+vector operation is desired when both operands are strings.
+See L<perlop/"Bitwise String Operators">.
+
+The following code will build up an ASCII string saying C<'PerlPerlPerl'>.
+The comments show the string after each step. Note that this code works
+in the same way on big-endian or little-endian machines.
+
+ my $foo = '';
+ vec($foo, 0, 32) = 0x5065726C; # 'Perl'
+
+ # $foo eq "Perl" eq "\x50\x65\x72\x6C", 32 bits
+ print vec($foo, 0, 8); # prints 80 == 0x50 == ord('P')
+
+ vec($foo, 2, 16) = 0x5065; # 'PerlPe'
+ vec($foo, 3, 16) = 0x726C; # 'PerlPerl'
+ vec($foo, 8, 8) = 0x50; # 'PerlPerlP'
+ vec($foo, 9, 8) = 0x65; # 'PerlPerlPe'
+ vec($foo, 20, 4) = 2; # 'PerlPerlPe' . "\x02"
+ vec($foo, 21, 4) = 7; # 'PerlPerlPer'
+ # 'r' is "\x72"
+ vec($foo, 45, 2) = 3; # 'PerlPerlPer' . "\x0c"
+ vec($foo, 93, 1) = 1; # 'PerlPerlPer' . "\x2c"
+ vec($foo, 94, 1) = 1; # 'PerlPerlPerl'
+ # 'l' is "\x6c"
+
+To transform a bit vector into a string or list of 0's and 1's, use these:
+
+ $bits = unpack("b*", $vector);
+ @bits = split(//, unpack("b*", $vector));
+
+If you know the exact length in bits, it can be used in place of the C<*>.
+
+Here is an example to illustrate how the bits actually fall in place:
+
+ #!/usr/bin/perl -wl
+
+ print <<'EOT';
+ 0 1 2 3
+ unpack("V",$_) 01234567890123456789012345678901
+ ------------------------------------------------------------------
+ EOT
+
+ for $w (0..3) {
+ $width = 2**$w;
+ for ($shift=0; $shift < $width; ++$shift) {
+ for ($off=0; $off < 32/$width; ++$off) {
+ $str = pack("B*", "0"x32);
+ $bits = (1<<$shift);
+ vec($str, $off, $width) = $bits;
+ $res = unpack("b*",$str);
+ $val = unpack("V", $str);
+ write;
+ }
+ }
+ }
+
+ format STDOUT =
+ vec($_,@#,@#) = @<< == @######### @>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+ $off, $width, $bits, $val, $res
+ .
+ __END__
+
+Regardless of the machine architecture on which it runs, the
+example above should print the following table:
+
+ 0 1 2 3
+ unpack("V",$_) 01234567890123456789012345678901
+ ------------------------------------------------------------------
+ vec($_, 0, 1) = 1 == 1 10000000000000000000000000000000
+ vec($_, 1, 1) = 1 == 2 01000000000000000000000000000000
+ vec($_, 2, 1) = 1 == 4 00100000000000000000000000000000
+ vec($_, 3, 1) = 1 == 8 00010000000000000000000000000000
+ vec($_, 4, 1) = 1 == 16 00001000000000000000000000000000
+ vec($_, 5, 1) = 1 == 32 00000100000000000000000000000000
+ vec($_, 6, 1) = 1 == 64 00000010000000000000000000000000
+ vec($_, 7, 1) = 1 == 128 00000001000000000000000000000000
+ vec($_, 8, 1) = 1 == 256 00000000100000000000000000000000
+ vec($_, 9, 1) = 1 == 512 00000000010000000000000000000000
+ vec($_,10, 1) = 1 == 1024 00000000001000000000000000000000
+ vec($_,11, 1) = 1 == 2048 00000000000100000000000000000000
+ vec($_,12, 1) = 1 == 4096 00000000000010000000000000000000
+ vec($_,13, 1) = 1 == 8192 00000000000001000000000000000000
+ vec($_,14, 1) = 1 == 16384 00000000000000100000000000000000
+ vec($_,15, 1) = 1 == 32768 00000000000000010000000000000000
+ vec($_,16, 1) = 1 == 65536 00000000000000001000000000000000
+ vec($_,17, 1) = 1 == 131072 00000000000000000100000000000000
+ vec($_,18, 1) = 1 == 262144 00000000000000000010000000000000
+ vec($_,19, 1) = 1 == 524288 00000000000000000001000000000000
+ vec($_,20, 1) = 1 == 1048576 00000000000000000000100000000000
+ vec($_,21, 1) = 1 == 2097152 00000000000000000000010000000000
+ vec($_,22, 1) = 1 == 4194304 00000000000000000000001000000000
+ vec($_,23, 1) = 1 == 8388608 00000000000000000000000100000000
+ vec($_,24, 1) = 1 == 16777216 00000000000000000000000010000000
+ vec($_,25, 1) = 1 == 33554432 00000000000000000000000001000000
+ vec($_,26, 1) = 1 == 67108864 00000000000000000000000000100000
+ vec($_,27, 1) = 1 == 134217728 00000000000000000000000000010000
+ vec($_,28, 1) = 1 == 268435456 00000000000000000000000000001000
+ vec($_,29, 1) = 1 == 536870912 00000000000000000000000000000100
+ vec($_,30, 1) = 1 == 1073741824 00000000000000000000000000000010
+ vec($_,31, 1) = 1 == 2147483648 00000000000000000000000000000001
+ vec($_, 0, 2) = 1 == 1 10000000000000000000000000000000
+ vec($_, 1, 2) = 1 == 4 00100000000000000000000000000000
+ vec($_, 2, 2) = 1 == 16 00001000000000000000000000000000
+ vec($_, 3, 2) = 1 == 64 00000010000000000000000000000000
+ vec($_, 4, 2) = 1 == 256 00000000100000000000000000000000
+ vec($_, 5, 2) = 1 == 1024 00000000001000000000000000000000
+ vec($_, 6, 2) = 1 == 4096 00000000000010000000000000000000
+ vec($_, 7, 2) = 1 == 16384 00000000000000100000000000000000
+ vec($_, 8, 2) = 1 == 65536 00000000000000001000000000000000
+ vec($_, 9, 2) = 1 == 262144 00000000000000000010000000000000
+ vec($_,10, 2) = 1 == 1048576 00000000000000000000100000000000
+ vec($_,11, 2) = 1 == 4194304 00000000000000000000001000000000
+ vec($_,12, 2) = 1 == 16777216 00000000000000000000000010000000
+ vec($_,13, 2) = 1 == 67108864 00000000000000000000000000100000
+ vec($_,14, 2) = 1 == 268435456 00000000000000000000000000001000
+ vec($_,15, 2) = 1 == 1073741824 00000000000000000000000000000010
+ vec($_, 0, 2) = 2 == 2 01000000000000000000000000000000
+ vec($_, 1, 2) = 2 == 8 00010000000000000000000000000000
+ vec($_, 2, 2) = 2 == 32 00000100000000000000000000000000
+ vec($_, 3, 2) = 2 == 128 00000001000000000000000000000000
+ vec($_, 4, 2) = 2 == 512 00000000010000000000000000000000
+ vec($_, 5, 2) = 2 == 2048 00000000000100000000000000000000
+ vec($_, 6, 2) = 2 == 8192 00000000000001000000000000000000
+ vec($_, 7, 2) = 2 == 32768 00000000000000010000000000000000
+ vec($_, 8, 2) = 2 == 131072 00000000000000000100000000000000
+ vec($_, 9, 2) = 2 == 524288 00000000000000000001000000000000
+ vec($_,10, 2) = 2 == 2097152 00000000000000000000010000000000
+ vec($_,11, 2) = 2 == 8388608 00000000000000000000000100000000
+ vec($_,12, 2) = 2 == 33554432 00000000000000000000000001000000
+ vec($_,13, 2) = 2 == 134217728 00000000000000000000000000010000
+ vec($_,14, 2) = 2 == 536870912 00000000000000000000000000000100
+ vec($_,15, 2) = 2 == 2147483648 00000000000000000000000000000001
+ vec($_, 0, 4) = 1 == 1 10000000000000000000000000000000
+ vec($_, 1, 4) = 1 == 16 00001000000000000000000000000000
+ vec($_, 2, 4) = 1 == 256 00000000100000000000000000000000
+ vec($_, 3, 4) = 1 == 4096 00000000000010000000000000000000
+ vec($_, 4, 4) = 1 == 65536 00000000000000001000000000000000
+ vec($_, 5, 4) = 1 == 1048576 00000000000000000000100000000000
+ vec($_, 6, 4) = 1 == 16777216 00000000000000000000000010000000
+ vec($_, 7, 4) = 1 == 268435456 00000000000000000000000000001000
+ vec($_, 0, 4) = 2 == 2 01000000000000000000000000000000
+ vec($_, 1, 4) = 2 == 32 00000100000000000000000000000000
+ vec($_, 2, 4) = 2 == 512 00000000010000000000000000000000
+ vec($_, 3, 4) = 2 == 8192 00000000000001000000000000000000
+ vec($_, 4, 4) = 2 == 131072 00000000000000000100000000000000
+ vec($_, 5, 4) = 2 == 2097152 00000000000000000000010000000000
+ vec($_, 6, 4) = 2 == 33554432 00000000000000000000000001000000
+ vec($_, 7, 4) = 2 == 536870912 00000000000000000000000000000100
+ vec($_, 0, 4) = 4 == 4 00100000000000000000000000000000
+ vec($_, 1, 4) = 4 == 64 00000010000000000000000000000000
+ vec($_, 2, 4) = 4 == 1024 00000000001000000000000000000000
+ vec($_, 3, 4) = 4 == 16384 00000000000000100000000000000000
+ vec($_, 4, 4) = 4 == 262144 00000000000000000010000000000000
+ vec($_, 5, 4) = 4 == 4194304 00000000000000000000001000000000
+ vec($_, 6, 4) = 4 == 67108864 00000000000000000000000000100000
+ vec($_, 7, 4) = 4 == 1073741824 00000000000000000000000000000010
+ vec($_, 0, 4) = 8 == 8 00010000000000000000000000000000
+ vec($_, 1, 4) = 8 == 128 00000001000000000000000000000000
+ vec($_, 2, 4) = 8 == 2048 00000000000100000000000000000000
+ vec($_, 3, 4) = 8 == 32768 00000000000000010000000000000000
+ vec($_, 4, 4) = 8 == 524288 00000000000000000001000000000000
+ vec($_, 5, 4) = 8 == 8388608 00000000000000000000000100000000
+ vec($_, 6, 4) = 8 == 134217728 00000000000000000000000000010000
+ vec($_, 7, 4) = 8 == 2147483648 00000000000000000000000000000001
+ vec($_, 0, 8) = 1 == 1 10000000000000000000000000000000
+ vec($_, 1, 8) = 1 == 256 00000000100000000000000000000000
+ vec($_, 2, 8) = 1 == 65536 00000000000000001000000000000000
+ vec($_, 3, 8) = 1 == 16777216 00000000000000000000000010000000
+ vec($_, 0, 8) = 2 == 2 01000000000000000000000000000000
+ vec($_, 1, 8) = 2 == 512 00000000010000000000000000000000
+ vec($_, 2, 8) = 2 == 131072 00000000000000000100000000000000
+ vec($_, 3, 8) = 2 == 33554432 00000000000000000000000001000000
+ vec($_, 0, 8) = 4 == 4 00100000000000000000000000000000
+ vec($_, 1, 8) = 4 == 1024 00000000001000000000000000000000
+ vec($_, 2, 8) = 4 == 262144 00000000000000000010000000000000
+ vec($_, 3, 8) = 4 == 67108864 00000000000000000000000000100000
+ vec($_, 0, 8) = 8 == 8 00010000000000000000000000000000
+ vec($_, 1, 8) = 8 == 2048 00000000000100000000000000000000
+ vec($_, 2, 8) = 8 == 524288 00000000000000000001000000000000
+ vec($_, 3, 8) = 8 == 134217728 00000000000000000000000000010000
+ vec($_, 0, 8) = 16 == 16 00001000000000000000000000000000
+ vec($_, 1, 8) = 16 == 4096 00000000000010000000000000000000
+ vec($_, 2, 8) = 16 == 1048576 00000000000000000000100000000000
+ vec($_, 3, 8) = 16 == 268435456 00000000000000000000000000001000
+ vec($_, 0, 8) = 32 == 32 00000100000000000000000000000000
+ vec($_, 1, 8) = 32 == 8192 00000000000001000000000000000000
+ vec($_, 2, 8) = 32 == 2097152 00000000000000000000010000000000
+ vec($_, 3, 8) = 32 == 536870912 00000000000000000000000000000100
+ vec($_, 0, 8) = 64 == 64 00000010000000000000000000000000
+ vec($_, 1, 8) = 64 == 16384 00000000000000100000000000000000
+ vec($_, 2, 8) = 64 == 4194304 00000000000000000000001000000000
+ vec($_, 3, 8) = 64 == 1073741824 00000000000000000000000000000010
+ vec($_, 0, 8) = 128 == 128 00000001000000000000000000000000
+ vec($_, 1, 8) = 128 == 32768 00000000000000010000000000000000
+ vec($_, 2, 8) = 128 == 8388608 00000000000000000000000100000000
+ vec($_, 3, 8) = 128 == 2147483648 00000000000000000000000000000001
+
+=item wait
+X<wait>
+
+Behaves like wait(2) on your system: it waits for a child
+process to terminate and returns the pid of the deceased process, or
+C<-1> if there are no child processes. The status is returned in C<$?>
+and C<${^CHILD_ERROR_NATIVE}>.
+Note that a return value of C<-1> could mean that child processes are
+being automatically reaped, as described in L<perlipc>.
+
+If you use wait in your handler for $SIG{CHLD} it may accidently wait for the
+child created by qx() or system(). See L<perlipc> for details.
+
+=item waitpid PID,FLAGS
+X<waitpid>
+
+Waits for a particular child process to terminate and returns the pid of
+the deceased process, or C<-1> if there is no such child process. On some
+systems, a value of 0 indicates that there are processes still running.
+The status is returned in C<$?> and C<${^CHILD_ERROR_NATIVE}>. If you say
+
+ use POSIX ":sys_wait_h";
+ #...
+ do {
+ $kid = waitpid(-1, WNOHANG);
+ } while $kid > 0;
+
+then you can do a non-blocking wait for all pending zombie processes.
+Non-blocking wait is available on machines supporting either the
+waitpid(2) or wait4(2) syscalls. However, waiting for a particular
+pid with FLAGS of C<0> is implemented everywhere. (Perl emulates the
+system call by remembering the status values of processes that have
+exited but have not been harvested by the Perl script yet.)
+
+Note that on some systems, a return value of C<-1> could mean that child
+processes are being automatically reaped. See L<perlipc> for details,
+and for other examples.
+
+=item wantarray
+X<wantarray> X<context>
+
+Returns true if the context of the currently executing subroutine or
+C<eval> is looking for a list value. Returns false if the context is
+looking for a scalar. Returns the undefined value if the context is
+looking for no value (void context).
+
+ return unless defined wantarray; # don't bother doing more
+ my @a = complex_calculation();
+ return wantarray ? @a : "@a";
+
+C<wantarray()>'s result is unspecified in the top level of a file,
+in a C<BEGIN>, C<UNITCHECK>, C<CHECK>, C<INIT> or C<END> block, or
+in a C<DESTROY> method.
+
+This function should have been named wantlist() instead.
+
+=item warn LIST
+X<warn> X<warning> X<STDERR>
+
+Prints the value of LIST to STDERR. If the last element of LIST does
+not end in a newline, it appends the same file/line number text as C<die>
+does.
+
+If the output is empty and C<$@> already contains a value (typically from a
+previous eval) that value is used after appending C<"\t...caught">
+to C<$@>. This is useful for staying almost, but not entirely similar to
+C<die>.
+
+If C<$@> is empty then the string C<"Warning: Something's wrong"> is used.
+
+No message is printed if there is a C<$SIG{__WARN__}> handler
+installed. It is the handler's responsibility to deal with the message
+as it sees fit (like, for instance, converting it into a C<die>). Most
+handlers must therefore arrange to actually display the
+warnings that they are not prepared to deal with, by calling C<warn>
+again in the handler. Note that this is quite safe and will not
+produce an endless loop, since C<__WARN__> hooks are not called from
+inside one.
+
+You will find this behavior is slightly different from that of
+C<$SIG{__DIE__}> handlers (which don't suppress the error text, but can
+instead call C<die> again to change it).
+
+Using a C<__WARN__> handler provides a powerful way to silence all
+warnings (even the so-called mandatory ones). An example:
+
+ # wipe out *all* compile-time warnings
+ BEGIN { $SIG{'__WARN__'} = sub { warn $_[0] if $DOWARN } }
+ my $foo = 10;
+ my $foo = 20; # no warning about duplicate my $foo,
+ # but hey, you asked for it!
+ # no compile-time or run-time warnings before here
+ $DOWARN = 1;
+
+ # run-time warnings enabled after here
+ warn "\$foo is alive and $foo!"; # does show up
+
+See L<perlvar> for details on setting C<%SIG> entries, and for more
+examples. See the Carp module for other kinds of warnings using its
+carp() and cluck() functions.
+
+=item write FILEHANDLE
+X<write>
+
+=item write EXPR
+
+=item write
+
+Writes a formatted record (possibly multi-line) to the specified FILEHANDLE,
+using the format associated with that file. By default the format for
+a file is the one having the same name as the filehandle, but the
+format for the current output channel (see the C<select> function) may be set
+explicitly by assigning the name of the format to the C<$~> variable.
+
+Top of form processing is handled automatically: if there is
+insufficient room on the current page for the formatted record, the
+page is advanced by writing a form feed, a special top-of-page format
+is used to format the new page header, and then the record is written.
+By default the top-of-page format is the name of the filehandle with
+"_TOP" appended, but it may be dynamically set to the format of your
+choice by assigning the name to the C<$^> variable while the filehandle is
+selected. The number of lines remaining on the current page is in
+variable C<$->, which can be set to C<0> to force a new page.
+
+If FILEHANDLE is unspecified, output goes to the current default output
+channel, which starts out as STDOUT but may be changed by the
+C<select> operator. If the FILEHANDLE is an EXPR, then the expression
+is evaluated and the resulting string is used to look up the name of
+the FILEHANDLE at run time. For more on formats, see L<perlform>.
+
+Note that write is I<not> the opposite of C<read>. Unfortunately.
+
+=item y///
+
+The transliteration operator. Same as C<tr///>. See
+L<perlop/"Quote and Quote-like Operators">.
+
+=back
diff --git a/Master/tlpkg/tlperl/lib/pods/perlglossary.pod b/Master/tlpkg/tlperl/lib/pods/perlglossary.pod
new file mode 100644
index 00000000000..b44fcd447f9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlglossary.pod
@@ -0,0 +1,3408 @@
+=head1 NAME
+
+perlglossary - Perl Glossary
+
+=head1 DESCRIPTION
+
+A glossary of terms (technical and otherwise) used in the Perl documentation.
+Other useful sources include the Free On-Line Dictionary of Computing
+L<http://foldoc.doc.ic.ac.uk/foldoc/index.html>, the Jargon File
+L<http://catb.org/~esr/jargon/>, and Wikipedia L<http://www.wikipedia.org/>.
+
+=head2 A
+
+=over 4
+
+=item accessor methods
+
+A L</method> used to indirectly inspect or update an L</object>'s
+state (its L<instance variables|/instance variable>).
+
+=item actual arguments
+
+The L<scalar values|/scalar value> that you supply to a L</function>
+or L</subroutine> when you call it. For instance, when you call
+C<power("puff")>, the string C<"puff"> is the actual argument. See
+also L</argument> and L</formal arguments>.
+
+=item address operator
+
+Some languages work directly with the memory addresses of values, but
+this can be like playing with fire. Perl provides a set of asbestos
+gloves for handling all memory management. The closest to an address
+operator in Perl is the backslash operator, but it gives you a L</hard
+reference>, which is much safer than a memory address.
+
+=item algorithm
+
+A well-defined sequence of steps, clearly enough explained that even a
+computer could do them.
+
+=item alias
+
+A nickname for something, which behaves in all ways as though you'd
+used the original name instead of the nickname. Temporary aliases are
+implicitly created in the loop variable for C<foreach> loops, in the
+C<$_> variable for L<map|perlfunc/map> or L<grep|perlfunc/grep>
+operators, in C<$a> and C<$b> during L<sort|perlfunc/sort>'s
+comparison function, and in each element of C<@_> for the L</actual
+arguments> of a subroutine call. Permanent aliases are explicitly
+created in L<packages|/package> by L<importing|/import> symbols or by
+assignment to L<typeglobs|/typeglob>. Lexically scoped aliases for
+package variables are explicitly created by the L<our|perlfunc/our>
+declaration.
+
+=item alternatives
+
+A list of possible choices from which you may select only one, as in
+"Would you like door A, B, or C?" Alternatives in regular expressions
+are separated with a single vertical bar: C<|>. Alternatives in
+normal Perl expressions are separated with a double vertical bar:
+C<||>. Logical alternatives in L</Boolean> expressions are separated
+with either C<||> or C<or>.
+
+=item anonymous
+
+Used to describe a L</referent> that is not directly accessible
+through a named L</variable>. Such a referent must be indirectly
+accessible through at least one L</hard reference>. When the last
+hard reference goes away, the anonymous referent is destroyed without
+pity.
+
+=item architecture
+
+The kind of computer you're working on, where one "kind" of computer
+means all those computers sharing a compatible machine language.
+Since Perl programs are (typically) simple text files, not executable
+images, a Perl program is much less sensitive to the architecture it's
+running on than programs in other languages, such as C, that are
+compiled into machine code. See also L</platform> and L</operating
+system>.
+
+=item argument
+
+A piece of data supplied to a L<program|/executable file>,
+L</subroutine>, L</function>, or L</method> to tell it what it's
+supposed to do. Also called a "parameter".
+
+=item ARGV
+
+The name of the array containing the L</argument> L</vector> from the
+command line. If you use the empty C<< E<lt>E<gt> >> operator, L</ARGV> is
+the name of both the L</filehandle> used to traverse the arguments and
+the L</scalar> containing the name of the current input file.
+
+=item arithmetical operator
+
+A L</symbol> such as C<+> or C</> that tells Perl to do the arithmetic
+you were supposed to learn in grade school.
+
+=item array
+
+An ordered sequence of L<values|/value>, stored such that you can
+easily access any of the values using an integer L</subscript>
+that specifies the value's L</offset> in the sequence.
+
+=item array context
+
+An archaic expression for what is more correctly referred to as
+L</list context>.
+
+=item ASCII
+
+The American Standard Code for Information Interchange (a 7-bit
+character set adequate only for poorly representing English text).
+Often used loosely to describe the lowest 128 values of the various
+ISO-8859-X character sets, a bunch of mutually incompatible 8-bit
+codes sometimes described as half ASCII. See also L</Unicode>.
+
+=item assertion
+
+A component of a L</regular expression> that must be true for the
+pattern to match but does not necessarily match any characters itself.
+Often used specifically to mean a L</zero width> assertion.
+
+=item assignment
+
+An L</operator> whose assigned mission in life is to change the value
+of a L</variable>.
+
+=item assignment operator
+
+Either a regular L</assignment>, or a compound L</operator> composed
+of an ordinary assignment and some other operator, that changes the
+value of a variable in place, that is, relative to its old value. For
+example, C<$a += 2> adds C<2> to C<$a>.
+
+=item associative array
+
+See L</hash>. Please.
+
+=item associativity
+
+Determines whether you do the left L</operator> first or the right
+L</operator> first when you have "A L</operator> B L</operator> C" and
+the two operators are of the same precedence. Operators like C<+> are
+left associative, while operators like C<**> are right associative.
+See L<perlop> for a list of operators and their associativity.
+
+=item asynchronous
+
+Said of events or activities whose relative temporal ordering is
+indeterminate because too many things are going on at once. Hence, an
+asynchronous event is one you didn't know when to expect.
+
+=item atom
+
+A L</regular expression> component potentially matching a
+L</substring> containing one or more characters and treated as an
+indivisible syntactic unit by any following L</quantifier>. (Contrast
+with an L</assertion> that matches something of L</zero width> and may
+not be quantified.)
+
+=item atomic operation
+
+When Democritus gave the word "atom" to the indivisible bits of
+matter, he meant literally something that could not be cut: I<a->
+(not) + I<tomos> (cuttable). An atomic operation is an action that
+can't be interrupted, not one forbidden in a nuclear-free zone.
+
+=item attribute
+
+A new feature that allows the declaration of L<variables|/variable>
+and L<subroutines|/subroutine> with modifiers as in C<sub foo : locked
+method>. Also, another name for an L</instance variable> of an
+L</object>.
+
+=item autogeneration
+
+A feature of L</operator overloading> of L<objects|/object>, whereby
+the behavior of certain L<operators|/operator> can be reasonably
+deduced using more fundamental operators. This assumes that the
+overloaded operators will often have the same relationships as the
+regular operators. See L<perlop>.
+
+=item autoincrement
+
+To add one to something automatically, hence the name of the C<++>
+operator. To instead subtract one from something automatically is
+known as an "autodecrement".
+
+=item autoload
+
+To load on demand. (Also called "lazy" loading.) Specifically, to
+call an L<AUTOLOAD|perlsub/Autoloading> subroutine on behalf of an
+undefined subroutine.
+
+=item autosplit
+
+To split a string automatically, as the B<-a> L</switch> does when
+running under B<-p> or B<-n> in order to emulate L</awk>. (See also
+the L<AutoSplit> module, which has nothing to do with the B<-a>
+switch, but a lot to do with autoloading.)
+
+=item autovivification
+
+A Greco-Roman word meaning "to bring oneself to life". In Perl,
+storage locations (L<lvalues|/lvalue>) spontaneously generate
+themselves as needed, including the creation of any L</hard reference>
+values to point to the next level of storage. The assignment
+C<$a[5][5][5][5][5] = "quintet"> potentially creates five scalar
+storage locations, plus four references (in the first four scalar
+locations) pointing to four new anonymous arrays (to hold the last
+four scalar locations). But the point of autovivification is that you
+don't have to worry about it.
+
+=item AV
+
+Short for "array value", which refers to one of Perl's internal data
+types that holds an L</array>. The L</AV> type is a subclass of
+L</SV>.
+
+=item awk
+
+Descriptive editing term--short for "awkward". Also coincidentally
+refers to a venerable text-processing language from which Perl derived
+some of its high-level ideas.
+
+=back
+
+=head2 B
+
+=over 4
+
+=item backreference
+
+A substring L<captured|/capturing> by a subpattern within
+unadorned parentheses in a L</regex>. Backslashed decimal numbers
+(C<\1>, C<\2>, etc.) later in the same pattern refer back to the
+corresponding subpattern in the current match. Outside the pattern,
+the numbered variables (C<$1>, C<$2>, etc.) continue to refer to these
+same values, as long as the pattern was the last successful match of
+the current dynamic scope.
+
+=item backtracking
+
+The practice of saying, "If I had to do it all over, I'd do it
+differently," and then actually going back and doing it all over
+differently. Mathematically speaking, it's returning from an
+unsuccessful recursion on a tree of possibilities. Perl backtracks
+when it attempts to match patterns with a L</regular expression>, and
+its earlier attempts don't pan out. See L<perlre/Backtracking>.
+
+=item backward compatibility
+
+Means you can still run your old program because we didn't break any
+of the features or bugs it was relying on.
+
+=item bareword
+
+A word sufficiently ambiguous to be deemed illegal under L<use strict
+'subs'|strict/strict subs>. In the absence of that stricture, a
+bareword is treated as if quotes were around it.
+
+=item base class
+
+A generic L</object> type; that is, a L</class> from which other, more
+specific classes are derived genetically by L</inheritance>. Also
+called a "superclass" by people who respect their ancestors.
+
+=item big-endian
+
+From Swift: someone who eats eggs big end first. Also used of
+computers that store the most significant L</byte> of a word at a
+lower byte address than the least significant byte. Often considered
+superior to little-endian machines. See also L</little-endian>.
+
+=item binary
+
+Having to do with numbers represented in base 2. That means there's
+basically two numbers, 0 and 1. Also used to describe a "non-text
+file", presumably because such a file makes full use of all the binary
+bits in its bytes. With the advent of L</Unicode>, this distinction,
+already suspect, loses even more of its meaning.
+
+=item binary operator
+
+An L</operator> that takes two L<operands|/operand>.
+
+=item bind
+
+To assign a specific L</network address> to a L</socket>.
+
+=item bit
+
+An integer in the range from 0 to 1, inclusive. The smallest possible
+unit of information storage. An eighth of a L</byte> or of a dollar.
+(The term "Pieces of Eight" comes from being able to split the old
+Spanish dollar into 8 bits, each of which still counted for money.
+That's why a 25-cent piece today is still "two bits".)
+
+=item bit shift
+
+The movement of bits left or right in a computer word, which has the
+effect of multiplying or dividing by a power of 2.
+
+=item bit string
+
+A sequence of L<bits|/bit> that is actually being thought of as a
+sequence of bits, for once.
+
+=item bless
+
+In corporate life, to grant official approval to a thing, as in, "The
+VP of Engineering has blessed our WebCruncher project." Similarly in
+Perl, to grant official approval to a L</referent> so that it can
+function as an L</object>, such as a WebCruncher object. See
+L<perlfunc/"bless">.
+
+=item block
+
+What a L</process> does when it has to wait for something: "My process
+blocked waiting for the disk." As an unrelated noun, it refers to a
+large chunk of data, of a size that the L</operating system> likes to
+deal with (normally a power of two such as 512 or 8192). Typically
+refers to a chunk of data that's coming from or going to a disk file.
+
+=item BLOCK
+
+A syntactic construct consisting of a sequence of Perl
+L<statements|/statement> that is delimited by braces. The C<if> and
+C<while> statements are defined in terms of L<BLOCKs|/BLOCK>, for instance.
+Sometimes we also say "block" to mean a lexical scope; that is, a
+sequence of statements that act like a L</BLOCK>, such as within an
+L<eval|perlfunc/eval> or a file, even though the statements aren't
+delimited by braces.
+
+=item block buffering
+
+A method of making input and output efficient by passing one L</block>
+at a time. By default, Perl does block buffering to disk files. See
+L</buffer> and L</command buffering>.
+
+=item Boolean
+
+A value that is either L</true> or L</false>.
+
+=item Boolean context
+
+A special kind of L</scalar context> used in conditionals to decide
+whether the L</scalar value> returned by an expression is L</true> or
+L</false>. Does not evaluate as either a string or a number. See
+L</context>.
+
+=item breakpoint
+
+A spot in your program where you've told the debugger to stop
+L<execution|/execute> so you can poke around and see whether anything
+is wrong yet.
+
+=item broadcast
+
+To send a L</datagram> to multiple destinations simultaneously.
+
+=item BSD
+
+A psychoactive drug, popular in the 80s, probably developed at
+U. C. Berkeley or thereabouts. Similar in many ways to the
+prescription-only medication called "System V", but infinitely more
+useful. (Or, at least, more fun.) The full chemical name is
+"Berkeley Standard Distribution".
+
+=item bucket
+
+A location in a L</hash table> containing (potentially) multiple
+entries whose keys "hash" to the same hash value according to its hash
+function. (As internal policy, you don't have to worry about it,
+unless you're into internals, or policy.)
+
+=item buffer
+
+A temporary holding location for data. L<Block buffering|/block
+buffering> means that the data is passed on to its destination
+whenever the buffer is full. L<Line buffering|/line buffering> means
+that it's passed on whenever a complete line is received. L<Command
+buffering|/command buffering> means that it's passed every time you do
+a L<print|perlfunc/print> command (or equivalent). If your output is
+unbuffered, the system processes it one byte at a time without the use
+of a holding area. This can be rather inefficient.
+
+=item built-in
+
+A L</function> that is predefined in the language. Even when hidden
+by L</overriding>, you can always get at a built-in function by
+L<qualifying|/qualified> its name with the C<CORE::> pseudo-package.
+
+=item bundle
+
+A group of related modules on L</CPAN>. (Also, sometimes refers to a
+group of command-line switches grouped into one L</switch cluster>.)
+
+=item byte
+
+A piece of data worth eight L<bits|/bit> in most places.
+
+=item bytecode
+
+A pidgin-like language spoken among 'droids when they don't wish to
+reveal their orientation (see L</endian>). Named after some similar
+languages spoken (for similar reasons) between compilers and
+interpreters in the late 20th century. These languages are
+characterized by representing everything as a
+non-architecture-dependent sequence of bytes.
+
+=back
+
+=head2 C
+
+=over 4
+
+=item C
+
+A language beloved by many for its inside-out L</type> definitions,
+inscrutable L</precedence> rules, and heavy L</overloading> of the
+function-call mechanism. (Well, actually, people first switched to C
+because they found lowercase identifiers easier to read than upper.)
+Perl is written in C, so it's not surprising that Perl borrowed a few
+ideas from it.
+
+=item C preprocessor
+
+The typical C compiler's first pass, which processes lines beginning
+with C<#> for conditional compilation and macro definition and does
+various manipulations of the program text based on the current
+definitions. Also known as I<cpp>(1).
+
+=item call by reference
+
+An L</argument>-passing mechanism in which the L</formal arguments>
+refer directly to the L</actual arguments>, and the L</subroutine> can
+change the actual arguments by changing the formal arguments. That
+is, the formal argument is an L</alias> for the actual argument. See
+also L</call by value>.
+
+=item call by value
+
+An L</argument>-passing mechanism in which the L</formal arguments>
+refer to a copy of the L</actual arguments>, and the L</subroutine>
+cannot change the actual arguments by changing the formal arguments.
+See also L</call by reference>.
+
+=item callback
+
+A L</handler> that you register with some other part of your program
+in the hope that the other part of your program will L</trigger> your
+handler when some event of interest transpires.
+
+=item canonical
+
+Reduced to a standard form to facilitate comparison.
+
+=item capturing
+
+The use of parentheses around a L</subpattern> in a L</regular
+expression> to store the matched L</substring> as a L</backreference>.
+(Captured strings are also returned as a list in L</list context>.)
+
+=item character
+
+A small integer representative of a unit of orthography.
+Historically, characters were usually stored as fixed-width integers
+(typically in a byte, or maybe two, depending on the character set),
+but with the advent of UTF-8, characters are often stored in a
+variable number of bytes depending on the size of the integer that
+represents the character. Perl manages this transparently for you,
+for the most part.
+
+=item character class
+
+A square-bracketed list of characters used in a L</regular expression>
+to indicate that any character of the set may occur at a given point.
+Loosely, any predefined set of characters so used.
+
+=item character property
+
+A predefined L</character class> matchable by the C<\p>
+L</metasymbol>. Many standard properties are defined for L</Unicode>.
+
+=item circumfix operator
+
+An L</operator> that surrounds its L</operand>, like the angle
+operator, or parentheses, or a hug.
+
+=item class
+
+A user-defined L</type>, implemented in Perl via a L</package> that
+provides (either directly or by inheritance) L<methods|/method> (that
+is, L<subroutines|/subroutine>) to handle L<instances|/instance> of
+the class (its L<objects|/object>). See also L</inheritance>.
+
+=item class method
+
+A L</method> whose L</invocant> is a L</package> name, not an
+L</object> reference. A method associated with the class as a whole.
+
+=item client
+
+In networking, a L</process> that initiates contact with a L</server>
+process in order to exchange data and perhaps receive a service.
+
+=item cloister
+
+A L</cluster> used to restrict the scope of a L</regular expression
+modifier>.
+
+=item closure
+
+An L</anonymous> subroutine that, when a reference to it is generated
+at run time, keeps track of the identities of externally visible
+L<lexical variables|/lexical variable> even after those lexical
+variables have supposedly gone out of L</scope>. They're called
+"closures" because this sort of behavior gives mathematicians a sense
+of closure.
+
+=item cluster
+
+A parenthesized L</subpattern> used to group parts of a L</regular
+expression> into a single L</atom>.
+
+=item CODE
+
+The word returned by the L<ref|perlfunc/ref> function when you apply
+it to a reference to a subroutine. See also L</CV>.
+
+=item code generator
+
+A system that writes code for you in a low-level language, such as
+code to implement the backend of a compiler. See L</program
+generator>.
+
+=item code subpattern
+
+A L</regular expression> subpattern whose real purpose is to execute
+some Perl code, for example, the C<(?{...})> and C<(??{...})>
+subpatterns.
+
+=item collating sequence
+
+The order into which L<characters|/character> sort. This is used by
+L</string> comparison routines to decide, for example, where in this
+glossary to put "collating sequence".
+
+=item command
+
+In L</shell> programming, the syntactic combination of a program name
+and its arguments. More loosely, anything you type to a shell (a
+command interpreter) that starts it doing something. Even more
+loosely, a Perl L</statement>, which might start with a L</label> and
+typically ends with a semicolon.
+
+=item command buffering
+
+A mechanism in Perl that lets you store up the output of each Perl
+L</command> and then flush it out as a single request to the
+L</operating system>. It's enabled by setting the C<$|>
+(C<$AUTOFLUSH>) variable to a true value. It's used when you don't
+want data sitting around not going where it's supposed to, which may
+happen because the default on a L</file> or L</pipe> is to use
+L</block buffering>.
+
+=item command name
+
+The name of the program currently executing, as typed on the command
+line. In C, the L</command> name is passed to the program as the
+first command-line argument. In Perl, it comes in separately as
+C<$0>.
+
+=item command-line arguments
+
+The L<values|/value> you supply along with a program name when you
+tell a L</shell> to execute a L</command>. These values are passed to
+a Perl program through C<@ARGV>.
+
+=item comment
+
+A remark that doesn't affect the meaning of the program. In Perl, a
+comment is introduced by a C<#> character and continues to the end of
+the line.
+
+=item compilation unit
+
+The L</file> (or L</string>, in the case of L<eval|perlfunc/eval>)
+that is currently being compiled.
+
+=item compile phase
+
+Any time before Perl starts running your main program. See also
+L</run phase>. Compile phase is mostly spent in L</compile time>, but
+may also be spent in L</run time> when C<BEGIN> blocks,
+L<use|perlfunc/use> declarations, or constant subexpressions are being
+evaluated. The startup and import code of any L<use|perlfunc/use>
+declaration is also run during compile phase.
+
+=item compile time
+
+The time when Perl is trying to make sense of your code, as opposed to
+when it thinks it knows what your code means and is merely trying to
+do what it thinks your code says to do, which is L</run time>.
+
+=item compiler
+
+Strictly speaking, a program that munches up another program and spits
+out yet another file containing the program in a "more executable"
+form, typically containing native machine instructions. The I<perl>
+program is not a compiler by this definition, but it does contain a
+kind of compiler that takes a program and turns it into a more
+executable form (L<syntax trees|/syntax tree>) within the I<perl>
+process itself, which the L</interpreter> then interprets. There are,
+however, extension L<modules|/module> to get Perl to act more like a
+"real" compiler. See L<O>.
+
+=item composer
+
+A "constructor" for a L</referent> that isn't really an L</object>,
+like an anonymous array or a hash (or a sonata, for that matter). For
+example, a pair of braces acts as a composer for a hash, and a pair of
+brackets acts as a composer for an array. See L<perlref/Making
+References>.
+
+=item concatenation
+
+The process of gluing one cat's nose to another cat's tail. Also, a
+similar operation on two L<strings|/string>.
+
+=item conditional
+
+Something "iffy". See L</Boolean context>.
+
+=item connection
+
+In telephony, the temporary electrical circuit between the caller's
+and the callee's phone. In networking, the same kind of temporary
+circuit between a L</client> and a L</server>.
+
+=item construct
+
+As a noun, a piece of syntax made up of smaller pieces. As a
+transitive verb, to create an L</object> using a L</constructor>.
+
+=item constructor
+
+Any L</class method>, instance L</method>, or L</subroutine>
+that composes, initializes, blesses, and returns an L</object>.
+Sometimes we use the term loosely to mean a L</composer>.
+
+=item context
+
+The surroundings, or environment. The context given by the
+surrounding code determines what kind of data a particular
+L</expression> is expected to return. The three primary contexts are
+L</list context>, L</scalar context>, and L</void context>. Scalar
+context is sometimes subdivided into L</Boolean context>, L</numeric
+context>, L</string context>, and L</void context>. There's also a
+"don't care" scalar context (which is dealt with in Programming Perl,
+Third Edition, Chapter 2, "Bits and Pieces" if you care).
+
+=item continuation
+
+The treatment of more than one physical L</line> as a single logical
+line. L</Makefile> lines are continued by putting a backslash before
+the L</newline>. Mail headers as defined by RFC 822 are continued by
+putting a space or tab I<after> the newline. In general, lines in
+Perl do not need any form of continuation mark, because L</whitespace>
+(including newlines) is gleefully ignored. Usually.
+
+=item core dump
+
+The corpse of a L</process>, in the form of a file left in the
+L</working directory> of the process, usually as a result of certain
+kinds of fatal error.
+
+=item CPAN
+
+The Comprehensive Perl Archive Network. (See L<perlfaq2/What modules and extensions are available for Perl? What is CPAN? What does CPANE<sol>srcE<sol>... mean?>).
+
+=item cracker
+
+Someone who breaks security on computer systems. A cracker may be a
+true L</hacker> or only a L</script kiddie>.
+
+=item current package
+
+The L</package> in which the current statement is compiled. Scan
+backwards in the text of your program through the current L<lexical
+scope|/lexical scoping> or any enclosing lexical scopes till you find
+a package declaration. That's your current package name.
+
+=item current working directory
+
+See L</working directory>.
+
+=item currently selected output channel
+
+The last L</filehandle> that was designated with
+L<select|perlfunc/select>(C<FILEHANDLE>); L</STDOUT>, if no filehandle
+has been selected.
+
+=item CV
+
+An internal "code value" typedef, holding a L</subroutine>. The L</CV>
+type is a subclass of L</SV>.
+
+=back
+
+=head2 D
+
+=over 4
+
+=item dangling statement
+
+A bare, single L</statement>, without any braces, hanging off an C<if>
+or C<while> conditional. C allows them. Perl doesn't.
+
+=item data structure
+
+How your various pieces of data relate to each other and what shape
+they make when you put them all together, as in a rectangular table or
+a triangular-shaped tree.
+
+=item data type
+
+A set of possible values, together with all the operations that know
+how to deal with those values. For example, a numeric data type has a
+certain set of numbers that you can work with and various mathematical
+operations that you can do on the numbers but would make little sense
+on, say, a string such as C<"Kilroy">. Strings have their own
+operations, such as L</concatenation>. Compound types made of a
+number of smaller pieces generally have operations to compose and
+decompose them, and perhaps to rearrange them. L<Objects|/object>
+that model things in the real world often have operations that
+correspond to real activities. For instance, if you model an
+elevator, your elevator object might have an C<open_door()>
+L</method>.
+
+=item datagram
+
+A packet of data, such as a L</UDP> message, that (from the viewpoint
+of the programs involved) can be sent independently over the network.
+(In fact, all packets are sent independently at the L</IP> level, but
+L</stream> protocols such as L</TCP> hide this from your program.)
+
+=item DBM
+
+Stands for "Data Base Management" routines, a set of routines that
+emulate an L</associative array> using disk files. The routines use a
+dynamic hashing scheme to locate any entry with only two disk
+accesses. DBM files allow a Perl program to keep a persistent
+L</hash> across multiple invocations. You can L<tie|perlfunc/tie>
+your hash variables to various DBM implementations--see L<AnyDBM_File>
+and L<DB_File>.
+
+=item declaration
+
+An L</assertion> that states something exists and perhaps describes
+what it's like, without giving any commitment as to how or where
+you'll use it. A declaration is like the part of your recipe that
+says, "two cups flour, one large egg, four or five tadpoles..." See
+L</statement> for its opposite. Note that some declarations also
+function as statements. Subroutine declarations also act as
+definitions if a body is supplied.
+
+=item decrement
+
+To subtract a value from a variable, as in "decrement C<$x>" (meaning
+to remove 1 from its value) or "decrement C<$x> by 3".
+
+=item default
+
+A L</value> chosen for you if you don't supply a value of your own.
+
+=item defined
+
+Having a meaning. Perl thinks that some of the things people try to
+do are devoid of meaning, in particular, making use of variables that
+have never been given a L</value> and performing certain operations on
+data that isn't there. For example, if you try to read data past the
+end of a file, Perl will hand you back an undefined value. See also
+L</false> and L<perlfunc/defined>.
+
+=item delimiter
+
+A L</character> or L</string> that sets bounds to an arbitrarily-sized
+textual object, not to be confused with a L</separator> or
+L</terminator>. "To delimit" really just means "to surround" or "to
+enclose" (like these parentheses are doing).
+
+=item deprecated modules and features
+
+Deprecated modules and features are those which were part of a stable
+release, but later found to be subtly flawed, and which should be avoided.
+They are subject to removal and/or bug-incompatible reimplementation in
+the next major release (but they will be preserved through maintenance
+releases). Deprecation warnings are issued under B<-w> or C<use
+diagnostics>, and notices are found in L<perldelta>s, as well as various
+other PODs. Coding practices that misuse features, such as C<my $foo if
+0>, can also be deprecated.
+
+=item dereference
+
+A fancy computer science term meaning "to follow a L</reference> to
+what it points to". The "de" part of it refers to the fact that
+you're taking away one level of L</indirection>.
+
+=item derived class
+
+A L</class> that defines some of its L<methods|/method> in terms of a
+more generic class, called a L</base class>. Note that classes aren't
+classified exclusively into base classes or derived classes: a class
+can function as both a derived class and a base class simultaneously,
+which is kind of classy.
+
+=item descriptor
+
+See L</file descriptor>.
+
+=item destroy
+
+To deallocate the memory of a L</referent> (first triggering its
+C<DESTROY> method, if it has one).
+
+=item destructor
+
+A special L</method> that is called when an L</object> is thinking
+about L<destroying|/destroy> itself. A Perl program's C<DESTROY>
+method doesn't do the actual destruction; Perl just
+L<triggers|/trigger> the method in case the L</class> wants to do any
+associated cleanup.
+
+=item device
+
+A whiz-bang hardware gizmo (like a disk or tape drive or a modem or a
+joystick or a mouse) attached to your computer, that the L</operating
+system> tries to make look like a L</file> (or a bunch of files).
+Under Unix, these fake files tend to live in the I</dev> directory.
+
+=item directive
+
+A L</pod> directive. See L<perlpod>.
+
+=item directory
+
+A special file that contains other files. Some L<operating
+systems|/operating system> call these "folders", "drawers", or
+"catalogs".
+
+=item directory handle
+
+A name that represents a particular instance of opening a directory to
+read it, until you close it. See the L<opendir|perlfunc/opendir>
+function.
+
+=item dispatch
+
+To send something to its correct destination. Often used
+metaphorically to indicate a transfer of programmatic control to a
+destination selected algorithmically, often by lookup in a table of
+function L<references|/reference> or, in the case of object
+L<methods|/method>, by traversing the inheritance tree looking for the
+most specific definition for the method.
+
+=item distribution
+
+A standard, bundled release of a system of software. The default
+usage implies source code is included. If that is not the case, it
+will be called a "binary-only" distribution.
+
+=item (to be) dropped modules
+
+When Perl 5 was first released (see L<perlhistory>), several modules were
+included, which have now fallen out of common use. It has been suggested
+that these modules should be removed, since the distribution became rather
+large, and the common criterion for new module additions is now limited to
+modules that help to build, test, and extend perl itself. Furthermore,
+the CPAN (which didn't exist at the time of Perl 5.0) can become the new
+home of dropped modules. Dropping modules is currently not an option, but
+further developments may clear the last barriers.
+
+=item dweomer
+
+An enchantment, illusion, phantasm, or jugglery. Said when Perl's
+magical L</dwimmer> effects don't do what you expect, but rather seem
+to be the product of arcane dweomercraft, sorcery, or wonder working.
+[From Old English]
+
+=item dwimmer
+
+DWIM is an acronym for "Do What I Mean", the principle that something
+should just do what you want it to do without an undue amount of fuss.
+A bit of code that does "dwimming" is a "dwimmer". Dwimming can
+require a great deal of behind-the-scenes magic, which (if it doesn't
+stay properly behind the scenes) is called a L</dweomer> instead.
+
+=item dynamic scoping
+
+Dynamic scoping works over a dynamic scope, making variables visible
+throughout the rest of the L</block> in which they are first used and
+in any L<subroutines|/subroutine> that are called by the rest of the
+block. Dynamically scoped variables can have their values temporarily
+changed (and implicitly restored later) by a L<local|perlfunc/local>
+operator. (Compare L</lexical scoping>.) Used more loosely to mean
+how a subroutine that is in the middle of calling another subroutine
+"contains" that subroutine at L</run time>.
+
+=back
+
+=head2 E
+
+=over 4
+
+=item eclectic
+
+Derived from many sources. Some would say I<too> many.
+
+=item element
+
+A basic building block. When you're talking about an L</array>, it's
+one of the items that make up the array.
+
+=item embedding
+
+When something is contained in something else, particularly when that
+might be considered surprising: "I've embedded a complete Perl
+interpreter in my editor!"
+
+=item empty subclass test
+
+The notion that an empty L</derived class> should behave exactly like
+its L</base class>.
+
+=item en passant
+
+When you change a L</value> as it is being copied. [From French, "in
+passing", as in the exotic pawn-capturing maneuver in chess.]
+
+=item encapsulation
+
+The veil of abstraction separating the L</interface> from the
+L</implementation> (whether enforced or not), which mandates that all
+access to an L</object>'s state be through L<methods|/method> alone.
+
+=item endian
+
+See L</little-endian> and L</big-endian>.
+
+=item environment
+
+The collective set of L<environment variables|/environment variable>
+your L</process> inherits from its parent. Accessed via C<%ENV>.
+
+=item environment variable
+
+A mechanism by which some high-level agent such as a user can pass its
+preferences down to its future offspring (child L<processes|/process>,
+grandchild processes, great-grandchild processes, and so on). Each
+environment variable is a L</key>/L</value> pair, like one entry in a
+L</hash>.
+
+=item EOF
+
+End of File. Sometimes used metaphorically as the terminating string
+of a L</here document>.
+
+=item errno
+
+The error number returned by a L</syscall> when it fails. Perl refers
+to the error by the name C<$!> (or C<$OS_ERROR> if you use the English
+module).
+
+=item error
+
+See L</exception> or L</fatal error>.
+
+=item escape sequence
+
+See L</metasymbol>.
+
+=item exception
+
+A fancy term for an error. See L</fatal error>.
+
+=item exception handling
+
+The way a program responds to an error. The exception handling
+mechanism in Perl is the L<eval|perlfunc/eval> operator.
+
+=item exec
+
+To throw away the current L</process>'s program and replace it with
+another without exiting the process or relinquishing any resources
+held (apart from the old memory image).
+
+=item executable file
+
+A L</file> that is specially marked to tell the L</operating system>
+that it's okay to run this file as a program. Usually shortened to
+"executable".
+
+=item execute
+
+To run a L<program|/executable file> or L</subroutine>. (Has nothing
+to do with the L<kill|perlfunc/kill> built-in, unless you're trying to
+run a L</signal handler>.)
+
+=item execute bit
+
+The special mark that tells the operating system it can run this
+program. There are actually three execute bits under Unix, and which
+bit gets used depends on whether you own the file singularly,
+collectively, or not at all.
+
+=item exit status
+
+See L</status>.
+
+=item export
+
+To make symbols from a L</module> available for L</import> by other modules.
+
+=item expression
+
+Anything you can legally say in a spot where a L</value> is required.
+Typically composed of L<literals|/literal>, L<variables|/variable>,
+L<operators|/operator>, L<functions|/function>, and L</subroutine>
+calls, not necessarily in that order.
+
+=item extension
+
+A Perl module that also pulls in compiled C or C++ code. More
+generally, any experimental option that can be compiled into Perl,
+such as multithreading.
+
+=back
+
+=head2 F
+
+=over 4
+
+=item false
+
+In Perl, any value that would look like C<""> or C<"0"> if evaluated
+in a string context. Since undefined values evaluate to C<"">, all
+undefined values are false, but not all false values are undefined.
+
+=item FAQ
+
+Frequently Asked Question (although not necessarily frequently
+answered, especially if the answer appears in the Perl FAQ shipped
+standard with Perl).
+
+=item fatal error
+
+An uncaught L</exception>, which causes termination of the L</process>
+after printing a message on your L</standard error> stream. Errors
+that happen inside an L<eval|perlfunc/eval> are not fatal. Instead,
+the L<eval|perlfunc/eval> terminates after placing the exception
+message in the C<$@> (C<$EVAL_ERROR>) variable. You can try to
+provoke a fatal error with the L<die|perlfunc/die> operator (known as
+throwing or raising an exception), but this may be caught by a
+dynamically enclosing L<eval|perlfunc/eval>. If not caught, the
+L<die|perlfunc/die> becomes a fatal error.
+
+=item field
+
+A single piece of numeric or string data that is part of a longer
+L</string>, L</record>, or L</line>. Variable-width fields are usually
+split up by L<separators|/separator> (so use L<split|perlfunc/split> to
+extract the fields), while fixed-width fields are usually at fixed
+positions (so use L<unpack|perlfunc/unpack>). L<Instance
+variables|/instance variable> are also known as fields.
+
+=item FIFO
+
+First In, First Out. See also L</LIFO>. Also, a nickname for a
+L</named pipe>.
+
+=item file
+
+A named collection of data, usually stored on disk in a L</directory>
+in a L</filesystem>. Roughly like a document, if you're into office
+metaphors. In modern filesystems, you can actually give a file more
+than one name. Some files have special properties, like directories
+and devices.
+
+=item file descriptor
+
+The little number the L</operating system> uses to keep track of which
+opened L</file> you're talking about. Perl hides the file descriptor
+inside a L</standard IE<sol>O> stream and then attaches the stream to
+a L</filehandle>.
+
+=item file test operator
+
+A built-in unary operator that you use to determine whether something
+is L</true> about a file, such as C<-o $filename> to test whether
+you're the owner of the file.
+
+=item fileglob
+
+A "wildcard" match on L<filenames|/filename>. See the
+L<glob|perlfunc/glob> function.
+
+=item filehandle
+
+An identifier (not necessarily related to the real name of a file)
+that represents a particular instance of opening a file until you
+close it. If you're going to open and close several different files
+in succession, it's fine to open each of them with the same
+filehandle, so you don't have to write out separate code to process
+each file.
+
+=item filename
+
+One name for a file. This name is listed in a L</directory>, and you
+can use it in an L<open|perlfunc/open> to tell the L</operating
+system> exactly which file you want to open, and associate the file
+with a L</filehandle> which will carry the subsequent identity of that
+file in your program, until you close it.
+
+=item filesystem
+
+A set of L<directories|/directory> and L<files|/file> residing on a
+partition of the disk. Sometimes known as a "partition". You can
+change the file's name or even move a file around from directory to
+directory within a filesystem without actually moving the file itself,
+at least under Unix.
+
+=item filter
+
+A program designed to take a L</stream> of input and transform it into
+a stream of output.
+
+=item flag
+
+We tend to avoid this term because it means so many things. It may
+mean a command-line L</switch> that takes no argument
+itself (such as Perl's B<-n> and B<-p>
+flags) or, less frequently, a single-bit indicator (such as the
+C<O_CREAT> and C<O_EXCL> flags used in
+L<sysopen|perlfunc/sysopen>).
+
+=item floating point
+
+A method of storing numbers in "scientific notation", such that the
+precision of the number is independent of its magnitude (the decimal
+point "floats"). Perl does its numeric work with floating-point
+numbers (sometimes called "floats"), when it can't get away with
+using L<integers|/integer>. Floating-point numbers are mere
+approximations of real numbers.
+
+=item flush
+
+The act of emptying a L</buffer>, often before it's full.
+
+=item FMTEYEWTK
+
+Far More Than Everything You Ever Wanted To Know. An exhaustive
+treatise on one narrow topic, something of a super-L</FAQ>. See Tom
+for far more.
+
+=item fork
+
+To create a child L</process> identical to the parent process at its
+moment of conception, at least until it gets ideas of its own. A
+thread with protected memory.
+
+=item formal arguments
+
+The generic names by which a L</subroutine> knows its
+L<arguments|/argument>. In many languages, formal arguments are
+always given individual names, but in Perl, the formal arguments are
+just the elements of an array. The formal arguments to a Perl program
+are C<$ARGV[0]>, C<$ARGV[1]>, and so on. Similarly, the formal
+arguments to a Perl subroutine are C<$_[0]>, C<$_[1]>, and so on. You
+may give the arguments individual names by assigning the values to a
+L<my|perlfunc/my> list. See also L</actual arguments>.
+
+=item format
+
+A specification of how many spaces and digits and things to put
+somewhere so that whatever you're printing comes out nice and pretty.
+
+=item freely available
+
+Means you don't have to pay money to get it, but the copyright on it
+may still belong to someone else (like Larry).
+
+=item freely redistributable
+
+Means you're not in legal trouble if you give a bootleg copy of it to
+your friends and we find out about it. In fact, we'd rather you gave
+a copy to all your friends.
+
+=item freeware
+
+Historically, any software that you give away, particularly if you
+make the source code available as well. Now often called C<open
+source software>. Recently there has been a trend to use the term in
+contradistinction to L</open source software>, to refer only to free
+software released under the Free Software Foundation's GPL (General
+Public License), but this is difficult to justify etymologically.
+
+=item function
+
+Mathematically, a mapping of each of a set of input values to a
+particular output value. In computers, refers to a L</subroutine> or
+L</operator> that returns a L</value>. It may or may not have input
+values (called L<arguments|/argument>).
+
+=item funny character
+
+Someone like Larry, or one of his peculiar friends. Also refers to
+the strange prefixes that Perl requires as noun markers on its
+variables.
+
+=item garbage collection
+
+A misnamed feature--it should be called, "expecting your mother to
+pick up after you". Strictly speaking, Perl doesn't do this, but it
+relies on a reference-counting mechanism to keep things tidy.
+However, we rarely speak strictly and will often refer to the
+reference-counting scheme as a form of garbage collection. (If it's
+any comfort, when your interpreter exits, a "real" garbage collector
+runs to make sure everything is cleaned up if you've been messy with
+circular references and such.)
+
+=back
+
+=head2 G
+
+=over 4
+
+=item GID
+
+Group ID--in Unix, the numeric group ID that the L</operating system>
+uses to identify you and members of your L</group>.
+
+=item glob
+
+Strictly, the shell's C<*> character, which will match a "glob" of
+characters when you're trying to generate a list of filenames.
+Loosely, the act of using globs and similar symbols to do pattern
+matching. See also L</fileglob> and L</typeglob>.
+
+=item global
+
+Something you can see from anywhere, usually used of
+L<variables|/variable> and L<subroutines|/subroutine> that are visible
+everywhere in your program. In Perl, only certain special variables
+are truly global--most variables (and all subroutines) exist only in
+the current L</package>. Global variables can be declared with
+L<our|perlfunc/our>. See L<perlfunc/our>.
+
+=item global destruction
+
+The L</garbage collection> of globals (and the running of any
+associated object destructors) that takes place when a Perl
+L</interpreter> is being shut down. Global destruction should not be
+confused with the Apocalypse, except perhaps when it should.
+
+=item glue language
+
+A language such as Perl that is good at hooking things together that
+weren't intended to be hooked together.
+
+=item granularity
+
+The size of the pieces you're dealing with, mentally speaking.
+
+=item greedy
+
+A L</subpattern> whose L</quantifier> wants to match as many things as
+possible.
+
+=item grep
+
+Originally from the old Unix editor command for "Globally search for a
+Regular Expression and Print it", now used in the general sense of any
+kind of search, especially text searches. Perl has a built-in
+L<grep|perlfunc/grep> function that searches a list for elements
+matching any given criterion, whereas the I<grep>(1) program searches
+for lines matching a L</regular expression> in one or more files.
+
+=item group
+
+A set of users of which you are a member. In some operating systems
+(like Unix), you can give certain file access permissions to other
+members of your group.
+
+=item GV
+
+An internal "glob value" typedef, holding a L</typeglob>. The L</GV>
+type is a subclass of L</SV>.
+
+=back
+
+=head2 H
+
+=over 4
+
+=item hacker
+
+Someone who is brilliantly persistent in solving technical problems,
+whether these involve golfing, fighting orcs, or programming. Hacker
+is a neutral term, morally speaking. Good hackers are not to be
+confused with evil L<crackers|/cracker> or clueless L<script
+kiddies|/script kiddie>. If you confuse them, we will presume that
+you are either evil or clueless.
+
+=item handler
+
+A L</subroutine> or L</method> that is called by Perl when your
+program needs to respond to some internal event, such as a L</signal>,
+or an encounter with an operator subject to L</operator overloading>.
+See also L</callback>.
+
+=item hard reference
+
+A L</scalar> L</value> containing the actual address of a
+L</referent>, such that the referent's L</reference> count accounts
+for it. (Some hard references are held internally, such as the
+implicit reference from one of a L</typeglob>'s variable slots to its
+corresponding referent.) A hard reference is different from a
+L</symbolic reference>.
+
+=item hash
+
+An unordered association of L</key>/L</value> pairs, stored such that
+you can easily use a string L</key> to look up its associated data
+L</value>. This glossary is like a hash, where the word to be defined
+is the key, and the definition is the value. A hash is also sometimes
+septisyllabically called an "associative array", which is a pretty
+good reason for simply calling it a "hash" instead.
+
+=item hash table
+
+A data structure used internally by Perl for implementing associative
+arrays (hashes) efficiently. See also L</bucket>.
+
+=item header file
+
+A file containing certain required definitions that you must include
+"ahead" of the rest of your program to do certain obscure operations.
+A C header file has a I<.h> extension. Perl doesn't really have
+header files, though historically Perl has sometimes used translated
+I<.h> files with a I<.ph> extension. See L<perlfunc/require>.
+(Header files have been superseded by the L</module> mechanism.)
+
+=item here document
+
+So called because of a similar construct in L<shells|/shell> that
+pretends that the L<lines|/line> following the L</command> are a
+separate L</file> to be fed to the command, up to some terminating
+string. In Perl, however, it's just a fancy form of quoting.
+
+=item hexadecimal
+
+A number in base 16, "hex" for short. The digits for 10 through 16
+are customarily represented by the letters C<a> through C<f>.
+Hexadecimal constants in Perl start with C<0x>. See also
+L<perlfunc/hex>.
+
+=item home directory
+
+The directory you are put into when you log in. On a Unix system, the
+name is often placed into C<$ENV{HOME}> or C<$ENV{LOGDIR}> by
+I<login>, but you can also find it with C<(getpwuid($E<lt>))[7]>.
+(Some platforms do not have a concept of a home directory.)
+
+=item host
+
+The computer on which a program or other data resides.
+
+=item hubris
+
+Excessive pride, the sort of thing Zeus zaps you for. Also the
+quality that makes you write (and maintain) programs that other people
+won't want to say bad things about. Hence, the third great virtue of
+a programmer. See also L</laziness> and L</impatience>.
+
+=item HV
+
+Short for a "hash value" typedef, which holds Perl's internal
+representation of a hash. The L</HV> type is a subclass of L</SV>.
+
+=back
+
+=head2 I
+
+=over 4
+
+=item identifier
+
+A legally formed name for most anything in which a computer program
+might be interested. Many languages (including Perl) allow
+identifiers that start with a letter and contain letters and digits.
+Perl also counts the underscore character as a valid letter. (Perl
+also has more complicated names, such as L</qualified> names.)
+
+=item impatience
+
+The anger you feel when the computer is being lazy. This makes you
+write programs that don't just react to your needs, but actually
+anticipate them. Or at least that pretend to. Hence, the second
+great virtue of a programmer. See also L</laziness> and L</hubris>.
+
+=item implementation
+
+How a piece of code actually goes about doing its job. Users of the
+code should not count on implementation details staying the same
+unless they are part of the published L</interface>.
+
+=item import
+
+To gain access to symbols that are exported from another module. See
+L<perlfunc/use>.
+
+=item increment
+
+To increase the value of something by 1 (or by some other number, if
+so specified).
+
+=item indexing
+
+In olden days, the act of looking up a L</key> in an actual index
+(such as a phone book), but now merely the act of using any kind of
+key or position to find the corresponding L</value>, even if no index
+is involved. Things have degenerated to the point that Perl's
+L<index|perlfunc/index> function merely locates the position (index)
+of one string in another.
+
+=item indirect filehandle
+
+An L</expression> that evaluates to something that can be used as a
+L</filehandle>: a L</string> (filehandle name), a L</typeglob>, a
+typeglob L</reference>, or a low-level L</IO> object.
+
+=item indirect object
+
+In English grammar, a short noun phrase between a verb and its direct
+object indicating the beneficiary or recipient of the action. In
+Perl, C<print STDOUT "$foo\n";> can be understood as "verb
+indirect-object object" where L</STDOUT> is the recipient of the
+L<print|perlfunc/print> action, and C<"$foo"> is the object being
+printed. Similarly, when invoking a L</method>, you might place the
+invocant between the method and its arguments:
+
+ $gollum = new Pathetic::Creature "Smeagol";
+ give $gollum "Fisssssh!";
+ give $gollum "Precious!";
+
+In modern Perl, calling methods this way is often considered bad practice and
+to be avoided.
+
+=item indirect object slot
+
+The syntactic position falling between a method call and its arguments
+when using the indirect object invocation syntax. (The slot is
+distinguished by the absence of a comma between it and the next
+argument.) L</STDERR> is in the indirect object slot here:
+
+ print STDERR "Awake! Awake! Fear, Fire,
+ Foes! Awake!\n";
+
+=item indirection
+
+If something in a program isn't the value you're looking for but
+indicates where the value is, that's indirection. This can be done
+with either L<symbolic references|/symbolic reference> or L<hard
+references|/hard reference>.
+
+=item infix
+
+An L</operator> that comes in between its L<operands|/operand>, such
+as multiplication in C<24 * 7>.
+
+=item inheritance
+
+What you get from your ancestors, genetically or otherwise. If you
+happen to be a L</class>, your ancestors are called L<base
+classes|/base class> and your descendants are called L<derived
+classes|/derived class>. See L</single inheritance> and L</multiple
+inheritance>.
+
+=item instance
+
+Short for "an instance of a class", meaning an L</object> of that L</class>.
+
+=item instance variable
+
+An L</attribute> of an L</object>; data stored with the particular
+object rather than with the class as a whole.
+
+=item integer
+
+A number with no fractional (decimal) part. A counting number, like
+1, 2, 3, and so on, but including 0 and the negatives.
+
+=item interface
+
+The services a piece of code promises to provide forever, in contrast to
+its L</implementation>, which it should feel free to change whenever it
+likes.
+
+=item interpolation
+
+The insertion of a scalar or list value somewhere in the middle of
+another value, such that it appears to have been there all along. In
+Perl, variable interpolation happens in double-quoted strings and
+patterns, and list interpolation occurs when constructing the list of
+values to pass to a list operator or other such construct that takes a
+L</LIST>.
+
+=item interpreter
+
+Strictly speaking, a program that reads a second program and does what
+the second program says directly without turning the program into a
+different form first, which is what L<compilers|/compiler> do. Perl
+is not an interpreter by this definition, because it contains a kind
+of compiler that takes a program and turns it into a more executable
+form (L<syntax trees|/syntax tree>) within the I<perl> process itself,
+which the Perl L</run time> system then interprets.
+
+=item invocant
+
+The agent on whose behalf a L</method> is invoked. In a L</class>
+method, the invocant is a package name. In an L</instance> method,
+the invocant is an object reference.
+
+=item invocation
+
+The act of calling up a deity, daemon, program, method, subroutine, or
+function to get it do what you think it's supposed to do. We usually
+"call" subroutines but "invoke" methods, since it sounds cooler.
+
+=item I/O
+
+Input from, or output to, a L</file> or L</device>.
+
+=item IO
+
+An internal I/O object. Can also mean L</indirect object>.
+
+=item IP
+
+Internet Protocol, or Intellectual Property.
+
+=item IPC
+
+Interprocess Communication.
+
+=item is-a
+
+A relationship between two L<objects|/object> in which one object is
+considered to be a more specific version of the other, generic object:
+"A camel is a mammal." Since the generic object really only exists in
+a Platonic sense, we usually add a little abstraction to the notion of
+objects and think of the relationship as being between a generic
+L</base class> and a specific L</derived class>. Oddly enough,
+Platonic classes don't always have Platonic relationships--see
+L</inheritance>.
+
+=item iteration
+
+Doing something repeatedly.
+
+=item iterator
+
+A special programming gizmo that keeps track of where you are in
+something that you're trying to iterate over. The C<foreach> loop in
+Perl contains an iterator; so does a hash, allowing you to
+L<each|perlfunc/each> through it.
+
+=item IV
+
+The integer four, not to be confused with six, Tom's favorite editor.
+IV also means an internal Integer Value of the type a L</scalar> can
+hold, not to be confused with an L</NV>.
+
+=back
+
+=head2 J
+
+=over 4
+
+=item JAPH
+
+"Just Another Perl Hacker," a clever but cryptic bit of Perl code that
+when executed, evaluates to that string. Often used to illustrate a
+particular Perl feature, and something of an ongoing Obfuscated Perl
+Contest seen in Usenix signatures.
+
+=back
+
+=head2 K
+
+=over 4
+
+=item key
+
+The string index to a L</hash>, used to look up the L</value>
+associated with that key.
+
+=item keyword
+
+See L</reserved words>.
+
+=back
+
+=head2 L
+
+=over 4
+
+=item label
+
+A name you give to a L</statement> so that you can talk about that
+statement elsewhere in the program.
+
+=item laziness
+
+The quality that makes you go to great effort to reduce overall energy
+expenditure. It makes you write labor-saving programs that other
+people will find useful, and document what you wrote so you don't have
+to answer so many questions about it. Hence, the first great virtue
+of a programmer. Also hence, this book. See also L</impatience> and
+L</hubris>.
+
+=item left shift
+
+A L</bit shift> that multiplies the number by some power of 2.
+
+=item leftmost longest
+
+The preference of the L</regular expression> engine to match the
+leftmost occurrence of a L</pattern>, then given a position at which a
+match will occur, the preference for the longest match (presuming the
+use of a L</greedy> quantifier). See L<perlre> for I<much> more on
+this subject.
+
+=item lexeme
+
+Fancy term for a L</token>.
+
+=item lexer
+
+Fancy term for a L</tokener>.
+
+=item lexical analysis
+
+Fancy term for L</tokenizing>.
+
+=item lexical scoping
+
+Looking at your I<Oxford English Dictionary> through a microscope.
+(Also known as L</static scoping>, because dictionaries don't change
+very fast.) Similarly, looking at variables stored in a private
+dictionary (namespace) for each scope, which are visible only from
+their point of declaration down to the end of the lexical scope in
+which they are declared. --Syn. L</static scoping>.
+--Ant. L</dynamic scoping>.
+
+=item lexical variable
+
+A L</variable> subject to L</lexical scoping>, declared by
+L<my|perlfunc/my>. Often just called a "lexical". (The
+L<our|perlfunc/our> declaration declares a lexically scoped name for a
+global variable, which is not itself a lexical variable.)
+
+=item library
+
+Generally, a collection of procedures. In ancient days, referred to a
+collection of subroutines in a I<.pl> file. In modern times, refers
+more often to the entire collection of Perl L<modules|/module> on your
+system.
+
+=item LIFO
+
+Last In, First Out. See also L</FIFO>. A LIFO is usually called a
+L</stack>.
+
+=item line
+
+In Unix, a sequence of zero or more non-newline characters terminated
+with a L</newline> character. On non-Unix machines, this is emulated
+by the C library even if the underlying L</operating system> has
+different ideas.
+
+=item line buffering
+
+Used by a L</standard IE<sol>O> output stream that flushes its
+L</buffer> after every L</newline>. Many standard I/O libraries
+automatically set up line buffering on output that is going to the
+terminal.
+
+=item line number
+
+The number of lines read previous to this one, plus 1. Perl keeps a
+separate line number for each source or input file it opens. The
+current source file's line number is represented by C<__LINE__>. The
+current input line number (for the file that was most recently read
+via C<< E<lt>FHE<gt> >>) is represented by the C<$.>
+(C<$INPUT_LINE_NUMBER>) variable. Many error messages report both
+values, if available.
+
+=item link
+
+Used as a noun, a name in a L</directory>, representing a L</file>. A
+given file can have multiple links to it. It's like having the same
+phone number listed in the phone directory under different names. As
+a verb, to resolve a partially compiled file's unresolved symbols into
+a (nearly) executable image. Linking can generally be static or
+dynamic, which has nothing to do with static or dynamic scoping.
+
+=item LIST
+
+A syntactic construct representing a comma-separated list of
+expressions, evaluated to produce a L</list value>. Each
+L</expression> in a L</LIST> is evaluated in L</list context> and
+interpolated into the list value.
+
+=item list
+
+An ordered set of scalar values.
+
+=item list context
+
+The situation in which an L</expression> is expected by its
+surroundings (the code calling it) to return a list of values rather
+than a single value. Functions that want a L</LIST> of arguments tell
+those arguments that they should produce a list value. See also
+L</context>.
+
+=item list operator
+
+An L</operator> that does something with a list of values, such as
+L<join|perlfunc/join> or L<grep|perlfunc/grep>. Usually used for
+named built-in operators (such as L<print|perlfunc/print>,
+L<unlink|perlfunc/unlink>, and L<system|perlfunc/system>) that do not
+require parentheses around their L</argument> list.
+
+=item list value
+
+An unnamed list of temporary scalar values that may be passed around
+within a program from any list-generating function to any function or
+construct that provides a L</list context>.
+
+=item literal
+
+A token in a programming language such as a number or L</string> that
+gives you an actual L</value> instead of merely representing possible
+values as a L</variable> does.
+
+=item little-endian
+
+From Swift: someone who eats eggs little end first. Also used of
+computers that store the least significant L</byte> of a word at a
+lower byte address than the most significant byte. Often considered
+superior to big-endian machines. See also L</big-endian>.
+
+=item local
+
+Not meaning the same thing everywhere. A global variable in Perl can
+be localized inside a L<dynamic scope|/dynamic scoping> via the
+L<local|perlfunc/local> operator.
+
+=item logical operator
+
+Symbols representing the concepts "and", "or", "xor", and "not".
+
+=item lookahead
+
+An L</assertion> that peeks at the string to the right of the current
+match location.
+
+=item lookbehind
+
+An L</assertion> that peeks at the string to the left of the current
+match location.
+
+=item loop
+
+A construct that performs something repeatedly, like a roller coaster.
+
+=item loop control statement
+
+Any statement within the body of a loop that can make a loop
+prematurely stop looping or skip an L</iteration>. Generally you
+shouldn't try this on roller coasters.
+
+=item loop label
+
+A kind of key or name attached to a loop (or roller coaster) so that
+loop control statements can talk about which loop they want to
+control.
+
+=item lvaluable
+
+Able to serve as an L</lvalue>.
+
+=item lvalue
+
+Term used by language lawyers for a storage location you can assign a
+new L</value> to, such as a L</variable> or an element of an
+L</array>. The "l" is short for "left", as in the left side of an
+assignment, a typical place for lvalues. An L</lvaluable> function or
+expression is one to which a value may be assigned, as in C<pos($x) =
+10>.
+
+=item lvalue modifier
+
+An adjectival pseudofunction that warps the meaning of an L</lvalue>
+in some declarative fashion. Currently there are three lvalue
+modifiers: L<my|perlfunc/my>, L<our|perlfunc/our>, and
+L<local|perlfunc/local>.
+
+=back
+
+=head2 M
+
+=over 4
+
+=item magic
+
+Technically speaking, any extra semantics attached to a variable such
+as C<$!>, C<$0>, C<%ENV>, or C<%SIG>, or to any tied variable.
+Magical things happen when you diddle those variables.
+
+=item magical increment
+
+An L</increment> operator that knows how to bump up alphabetics as
+well as numbers.
+
+=item magical variables
+
+Special variables that have side effects when you access them or
+assign to them. For example, in Perl, changing elements of the
+C<%ENV> array also changes the corresponding environment variables
+that subprocesses will use. Reading the C<$!> variable gives you the
+current system error number or message.
+
+=item Makefile
+
+A file that controls the compilation of a program. Perl programs
+don't usually need a L</Makefile> because the Perl compiler has plenty
+of self-control.
+
+=item man
+
+The Unix program that displays online documentation (manual pages) for
+you.
+
+=item manpage
+
+A "page" from the manuals, typically accessed via the I<man>(1)
+command. A manpage contains a SYNOPSIS, a DESCRIPTION, a list of
+BUGS, and so on, and is typically longer than a page. There are
+manpages documenting L<commands|/command>, L<syscalls|/syscall>,
+L</library> L<functions|/function>, L<devices|/device>,
+L<protocols|/protocol>, L<files|/file>, and such. In this book, we
+call any piece of standard Perl documentation (like I<perlop> or
+I<perldelta>) a manpage, no matter what format it's installed in on
+your system.
+
+=item matching
+
+See L</pattern matching>.
+
+=item member data
+
+See L</instance variable>.
+
+=item memory
+
+This always means your main memory, not your disk. Clouding the issue
+is the fact that your machine may implement L</virtual> memory; that
+is, it will pretend that it has more memory than it really does, and
+it'll use disk space to hold inactive bits. This can make it seem
+like you have a little more memory than you really do, but it's not a
+substitute for real memory. The best thing that can be said about
+virtual memory is that it lets your performance degrade gradually
+rather than suddenly when you run out of real memory. But your
+program can die when you run out of virtual memory too, if you haven't
+thrashed your disk to death first.
+
+=item metacharacter
+
+A L</character> that is I<not> supposed to be treated normally. Which
+characters are to be treated specially as metacharacters varies
+greatly from context to context. Your L</shell> will have certain
+metacharacters, double-quoted Perl L<strings|/string> have other
+metacharacters, and L</regular expression> patterns have all the
+double-quote metacharacters plus some extra ones of their own.
+
+=item metasymbol
+
+Something we'd call a L</metacharacter> except that it's a sequence of
+more than one character. Generally, the first character in the
+sequence must be a true metacharacter to get the other characters in
+the metasymbol to misbehave along with it.
+
+=item method
+
+A kind of action that an L</object> can take if you tell it to. See
+L<perlobj>.
+
+=item minimalism
+
+The belief that "small is beautiful." Paradoxically, if you say
+something in a small language, it turns out big, and if you say it in
+a big language, it turns out small. Go figure.
+
+=item mode
+
+In the context of the L<stat> syscall, refers to the field holding
+the L</permission bits> and the type of the L</file>.
+
+=item modifier
+
+See L</statement modifier>, L</regular expression modifier>, and
+L</lvalue modifier>, not necessarily in that order.
+
+=item module
+
+A L</file> that defines a L</package> of (almost) the same name, which
+can either L</export> symbols or function as an L</object> class. (A
+module's main I<.pm> file may also load in other files in support of
+the module.) See the L<use|perlfunc/use> built-in.
+
+=item modulus
+
+An integer divisor when you're interested in the remainder instead of
+the quotient.
+
+=item monger
+
+Short for Perl Monger, a purveyor of Perl.
+
+=item mortal
+
+A temporary value scheduled to die when the current statement
+finishes.
+
+=item multidimensional array
+
+An array with multiple subscripts for finding a single element. Perl
+implements these using L<references|/reference>--see L<perllol> and
+L<perldsc>.
+
+=item multiple inheritance
+
+The features you got from your mother and father, mixed together
+unpredictably. (See also L</inheritance>, and L</single
+inheritance>.) In computer languages (including Perl), the notion
+that a given class may have multiple direct ancestors or L<base
+classes|/base class>.
+
+=back
+
+=head2 N
+
+=over 4
+
+=item named pipe
+
+A L</pipe> with a name embedded in the L</filesystem> so that it can
+be accessed by two unrelated L<processes|/process>.
+
+=item namespace
+
+A domain of names. You needn't worry about whether the names in one
+such domain have been used in another. See L</package>.
+
+=item network address
+
+The most important attribute of a socket, like your telephone's
+telephone number. Typically an IP address. See also L</port>.
+
+=item newline
+
+A single character that represents the end of a line, with the ASCII
+value of 012 octal under Unix (but 015 on a Mac), and represented by
+C<\n> in Perl strings. For Windows machines writing text files, and
+for certain physical devices like terminals, the single newline gets
+automatically translated by your C library into a line feed and a
+carriage return, but normally, no translation is done.
+
+=item NFS
+
+Network File System, which allows you to mount a remote filesystem as
+if it were local.
+
+=item null character
+
+A character with the ASCII value of zero. It's used by C to terminate
+strings, but Perl allows strings to contain a null.
+
+=item null list
+
+A L</list value> with zero elements, represented in Perl by C<()>.
+
+=item null string
+
+A L</string> containing no characters, not to be confused with a
+string containing a L</null character>, which has a positive length
+and is L</true>.
+
+=item numeric context
+
+The situation in which an expression is expected by its surroundings
+(the code calling it) to return a number. See also L</context> and
+L</string context>.
+
+=item NV
+
+Short for Nevada, no part of which will ever be confused with
+civilization. NV also means an internal floating-point Numeric Value
+of the type a L</scalar> can hold, not to be confused with an L</IV>.
+
+=item nybble
+
+Half a L</byte>, equivalent to one L</hexadecimal> digit, and worth
+four L<bits|/bit>.
+
+=back
+
+=head2 O
+
+=over 4
+
+=item object
+
+An L</instance> of a L</class>. Something that "knows" what
+user-defined type (class) it is, and what it can do because of what
+class it is. Your program can request an object to do things, but the
+object gets to decide whether it wants to do them or not. Some
+objects are more accommodating than others.
+
+=item octal
+
+A number in base 8. Only the digits 0 through 7 are allowed. Octal
+constants in Perl start with 0, as in 013. See also the
+L<oct|perlfunc/oct> function.
+
+=item offset
+
+How many things you have to skip over when moving from the beginning
+of a string or array to a specific position within it. Thus, the
+minimum offset is zero, not one, because you don't skip anything to
+get to the first item.
+
+=item one-liner
+
+An entire computer program crammed into one line of text.
+
+=item open source software
+
+Programs for which the source code is freely available and freely
+redistributable, with no commercial strings attached. For a more
+detailed definition, see L<http://www.opensource.org/osd.html>.
+
+=item operand
+
+An L</expression> that yields a L</value> that an L</operator>
+operates on. See also L</precedence>.
+
+=item operating system
+
+A special program that runs on the bare machine and hides the gory
+details of managing L<processes|/process> and L<devices|/device>.
+Usually used in a looser sense to indicate a particular culture of
+programming. The loose sense can be used at varying levels of
+specificity. At one extreme, you might say that all versions of Unix
+and Unix-lookalikes are the same operating system (upsetting many
+people, especially lawyers and other advocates). At the other
+extreme, you could say this particular version of this particular
+vendor's operating system is different from any other version of this
+or any other vendor's operating system. Perl is much more portable
+across operating systems than many other languages. See also
+L</architecture> and L</platform>.
+
+=item operator
+
+A gizmo that transforms some number of input values to some number of
+output values, often built into a language with a special syntax or
+symbol. A given operator may have specific expectations about what
+L<types|/type> of data you give as its arguments
+(L<operands|/operand>) and what type of data you want back from it.
+
+=item operator overloading
+
+A kind of L</overloading> that you can do on built-in
+L<operators|/operator> to make them work on L<objects|/object> as if
+the objects were ordinary scalar values, but with the actual semantics
+supplied by the object class. This is set up with the L<overload>
+L</pragma>.
+
+=item options
+
+See either L<switches|/switch> or L</regular expression modifier>.
+
+=item overloading
+
+Giving additional meanings to a symbol or construct. Actually, all
+languages do overloading to one extent or another, since people are
+good at figuring out things from L</context>.
+
+=item overriding
+
+Hiding or invalidating some other definition of the same name. (Not
+to be confused with L</overloading>, which adds definitions that must
+be disambiguated some other way.) To confuse the issue further, we use
+the word with two overloaded definitions: to describe how you can
+define your own L</subroutine> to hide a built-in L</function> of the
+same name (see L<perlsub/Overriding Built-in Functions>) and to
+describe how you can define a replacement L</method> in a L</derived
+class> to hide a L</base class>'s method of the same name (see
+L<perlobj>).
+
+=item owner
+
+The one user (apart from the superuser) who has absolute control over
+a L</file>. A file may also have a L</group> of users who may
+exercise joint ownership if the real owner permits it. See
+L</permission bits>.
+
+=back
+
+=head2 P
+
+=over 4
+
+=item package
+
+A L</namespace> for global L<variables|/variable>,
+L<subroutines|/subroutine>, and the like, such that they can be kept
+separate from like-named L<symbols|/symbol> in other namespaces. In a
+sense, only the package is global, since the symbols in the package's
+symbol table are only accessible from code compiled outside the
+package by naming the package. But in another sense, all package
+symbols are also globals--they're just well-organized globals.
+
+=item pad
+
+Short for L</scratchpad>.
+
+=item parameter
+
+See L</argument>.
+
+=item parent class
+
+See L</base class>.
+
+=item parse tree
+
+See L</syntax tree>.
+
+=item parsing
+
+The subtle but sometimes brutal art of attempting to turn your
+possibly malformed program into a valid L</syntax tree>.
+
+=item patch
+
+To fix by applying one, as it were. In the realm of hackerdom, a
+listing of the differences between two versions of a program as might
+be applied by the I<patch>(1) program when you want to fix a bug or
+upgrade your old version.
+
+=item PATH
+
+The list of L<directories|/directory> the system searches to find a
+program you want to L</execute>. The list is stored as one of your
+L<environment variables|/environment variable>, accessible in Perl as
+C<$ENV{PATH}>.
+
+=item pathname
+
+A fully qualified filename such as I</usr/bin/perl>. Sometimes
+confused with L</PATH>.
+
+=item pattern
+
+A template used in L</pattern matching>.
+
+=item pattern matching
+
+Taking a pattern, usually a L</regular expression>, and trying the
+pattern various ways on a string to see whether there's any way to
+make it fit. Often used to pick interesting tidbits out of a file.
+
+=item permission bits
+
+Bits that the L</owner> of a file sets or unsets to allow or disallow
+access to other people. These flag bits are part of the L</mode> word
+returned by the L<stat|perlfunc/stat> built-in when you ask about a
+file. On Unix systems, you can check the I<ls>(1) manpage for more
+information.
+
+=item Pern
+
+What you get when you do C<Perl++> twice. Doing it only once will
+curl your hair. You have to increment it eight times to shampoo your
+hair. Lather, rinse, iterate.
+
+=item pipe
+
+A direct L</connection> that carries the output of one L</process> to
+the input of another without an intermediate temporary file. Once the
+pipe is set up, the two processes in question can read and write as if
+they were talking to a normal file, with some caveats.
+
+=item pipeline
+
+A series of L<processes|/process> all in a row, linked by
+L<pipes|/pipe>, where each passes its output stream to the next.
+
+=item platform
+
+The entire hardware and software context in which a program runs. A
+ program written in a platform-dependent language might break if you
+change any of: machine, operating system, libraries, compiler, or
+system configuration. The I<perl> interpreter has to be compiled
+differently for each platform because it is implemented in C, but
+programs written in the Perl language are largely
+platform-independent.
+
+=item pod
+
+The markup used to embed documentation into your Perl code. See
+L<perlpod>.
+
+=item pointer
+
+A L</variable> in a language like C that contains the exact memory
+location of some other item. Perl handles pointers internally so you
+don't have to worry about them. Instead, you just use symbolic
+pointers in the form of L<keys|/key> and L</variable> names, or L<hard
+references|/hard reference>, which aren't pointers (but act like
+pointers and do in fact contain pointers).
+
+=item polymorphism
+
+The notion that you can tell an L</object> to do something generic,
+and the object will interpret the command in different ways depending
+on its type. [E<lt>Gk many shapes]
+
+=item port
+
+The part of the address of a TCP or UDP socket that directs packets to
+the correct process after finding the right machine, something like
+the phone extension you give when you reach the company operator.
+Also, the result of converting code to run on a different platform
+than originally intended, or the verb denoting this conversion.
+
+=item portable
+
+Once upon a time, C code compilable under both BSD and SysV. In
+general, code that can be easily converted to run on another
+L</platform>, where "easily" can be defined however you like, and
+usually is. Anything may be considered portable if you try hard
+enough. See I<mobile home> or I<London Bridge>.
+
+=item porter
+
+Someone who "carries" software from one L</platform> to another.
+Porting programs written in platform-dependent languages such as C can
+be difficult work, but porting programs like Perl is very much worth
+the agony.
+
+=item POSIX
+
+The Portable Operating System Interface specification.
+
+=item postfix
+
+An L</operator> that follows its L</operand>, as in C<$x++>.
+
+=item pp
+
+An internal shorthand for a "push-pop" code, that is, C code
+implementing Perl's stack machine.
+
+=item pragma
+
+A standard module whose practical hints and suggestions are received
+(and possibly ignored) at compile time. Pragmas are named in all
+lowercase.
+
+=item precedence
+
+The rules of conduct that, in the absence of other guidance, determine
+what should happen first. For example, in the absence of parentheses,
+you always do multiplication before addition.
+
+=item prefix
+
+An L</operator> that precedes its L</operand>, as in C<++$x>.
+
+=item preprocessing
+
+What some helper L</process> did to transform the incoming data into a
+form more suitable for the current process. Often done with an
+incoming L</pipe>. See also L</C preprocessor>.
+
+=item procedure
+
+A L</subroutine>.
+
+=item process
+
+An instance of a running program. Under multitasking systems like
+Unix, two or more separate processes could be running the same program
+independently at the same time--in fact, the L<fork|perlfunc/fork>
+function is designed to bring about this happy state of affairs.
+Under other operating systems, processes are sometimes called
+"threads", "tasks", or "jobs", often with slight nuances in meaning.
+
+=item program generator
+
+A system that algorithmically writes code for you in a high-level
+language. See also L</code generator>.
+
+=item progressive matching
+
+L<Pattern matching|/pattern matching> that picks up where it left off before.
+
+=item property
+
+See either L</instance variable> or L</character property>.
+
+=item protocol
+
+In networking, an agreed-upon way of sending messages back and forth
+so that neither correspondent will get too confused.
+
+=item prototype
+
+An optional part of a L</subroutine> declaration telling the Perl
+compiler how many and what flavor of arguments may be passed as
+L</actual arguments>, so that you can write subroutine calls that
+parse much like built-in functions. (Or don't parse, as the case may
+be.)
+
+=item pseudofunction
+
+A construct that sometimes looks like a function but really isn't.
+Usually reserved for L</lvalue> modifiers like L<my|perlfunc/my>, for
+L</context> modifiers like L<scalar|perlfunc/scalar>, and for the
+pick-your-own-quotes constructs, C<q//>, C<qq//>, C<qx//>, C<qw//>,
+C<qr//>, C<m//>, C<s///>, C<y///>, and C<tr///>.
+
+=item pseudohash
+
+A reference to an array whose initial element happens to hold a
+reference to a hash. You can treat a pseudohash reference as either
+an array reference or a hash reference.
+
+=item pseudoliteral
+
+An L</operator> that looks something like a L</literal>, such as the
+output-grabbing operator, C<`>I<C<command>>C<`>.
+
+=item public domain
+
+Something not owned by anybody. Perl is copyrighted and is thus
+I<not> in the public domain--it's just L</freely available> and
+L</freely redistributable>.
+
+=item pumpkin
+
+A notional "baton" handed around the Perl community indicating who is
+the lead integrator in some arena of development.
+
+=item pumpking
+
+A L</pumpkin> holder, the person in charge of pumping the pump, or at
+least priming it. Must be willing to play the part of the Great
+Pumpkin now and then.
+
+=item PV
+
+A "pointer value", which is Perl Internals Talk for a C<char*>.
+
+=back
+
+=head2 Q
+
+=over 4
+
+=item qualified
+
+Possessing a complete name. The symbol C<$Ent::moot> is qualified;
+C<$moot> is unqualified. A fully qualified filename is specified from
+the top-level directory.
+
+=item quantifier
+
+A component of a L</regular expression> specifying how many times the
+foregoing L</atom> may occur.
+
+=back
+
+=head2 R
+
+=over 4
+
+=item readable
+
+With respect to files, one that has the proper permission bit set to
+let you access the file. With respect to computer programs, one
+that's written well enough that someone has a chance of figuring out
+what it's trying to do.
+
+=item reaping
+
+The last rites performed by a parent L</process> on behalf of a
+deceased child process so that it doesn't remain a L</zombie>. See
+the L<wait|perlfunc/wait> and L<waitpid|perlfunc/waitpid> function
+calls.
+
+=item record
+
+A set of related data values in a L</file> or L</stream>, often
+associated with a unique L</key> field. In Unix, often commensurate
+with a L</line>, or a blank-line-terminated set of lines (a
+"paragraph"). Each line of the I</etc/passwd> file is a record, keyed
+on login name, containing information about that user.
+
+=item recursion
+
+The art of defining something (at least partly) in terms of itself,
+which is a naughty no-no in dictionaries but often works out okay in
+computer programs if you're careful not to recurse forever, which is
+like an infinite loop with more spectacular failure modes.
+
+=item reference
+
+Where you look to find a pointer to information somewhere else. (See
+L</indirection>.) References come in two flavors, L<symbolic
+references|/symbolic reference> and L<hard references|/hard
+reference>.
+
+=item referent
+
+Whatever a reference refers to, which may or may not have a name.
+Common types of referents include scalars, arrays, hashes, and
+subroutines.
+
+=item regex
+
+See L</regular expression>.
+
+=item regular expression
+
+A single entity with various interpretations, like an elephant. To a
+computer scientist, it's a grammar for a little language in which some
+strings are legal and others aren't. To normal people, it's a pattern
+you can use to find what you're looking for when it varies from case
+to case. Perl's regular expressions are far from regular in the
+theoretical sense, but in regular use they work quite well. Here's a
+regular expression: C</Oh s.*t./>. This will match strings like "C<Oh
+say can you see by the dawn's early light>" and "C<Oh sit!>". See
+L<perlre>.
+
+=item regular expression modifier
+
+An option on a pattern or substitution, such as C</i> to render the
+pattern case insensitive. See also L</cloister>.
+
+=item regular file
+
+A L</file> that's not a L</directory>, a L</device>, a named L</pipe>
+or L</socket>, or a L</symbolic link>. Perl uses the C<-f> file test
+operator to identify regular files. Sometimes called a "plain" file.
+
+=item relational operator
+
+An L</operator> that says whether a particular ordering relationship
+is L</true> about a pair of L<operands|/operand>. Perl has both
+numeric and string relational operators. See L</collating sequence>.
+
+=item reserved words
+
+A word with a specific, built-in meaning to a L</compiler>, such as
+C<if> or L<delete|perlfunc/delete>. In many languages (not Perl),
+it's illegal to use reserved words to name anything else. (Which is
+why they're reserved, after all.) In Perl, you just can't use them to
+name L<labels|/label> or L<filehandles|/filehandle>. Also called
+"keywords".
+
+=item return value
+
+The L</value> produced by a L</subroutine> or L</expression> when
+evaluated. In Perl, a return value may be either a L</list> or a
+L</scalar>.
+
+=item RFC
+
+Request For Comment, which despite the timid connotations is the name
+of a series of important standards documents.
+
+=item right shift
+
+A L</bit shift> that divides a number by some power of 2.
+
+=item root
+
+The superuser (UID == 0). Also, the top-level directory of the
+filesystem.
+
+=item RTFM
+
+What you are told when someone thinks you should Read The Fine Manual.
+
+=item run phase
+
+Any time after Perl starts running your main program. See also
+L</compile phase>. Run phase is mostly spent in L</run time> but may
+also be spent in L</compile time> when L<require|perlfunc/require>,
+L<do|perlfunc/do> C<FILE>, or L<eval|perlfunc/eval> C<STRING>
+operators are executed or when a substitution uses the C</ee>
+modifier.
+
+=item run time
+
+The time when Perl is actually doing what your code says to do, as
+opposed to the earlier period of time when it was trying to figure out
+whether what you said made any sense whatsoever, which is L</compile
+time>.
+
+=item run-time pattern
+
+A pattern that contains one or more variables to be interpolated
+before parsing the pattern as a L</regular expression>, and that
+therefore cannot be analyzed at compile time, but must be re-analyzed
+each time the pattern match operator is evaluated. Run-time patterns
+are useful but expensive.
+
+=item RV
+
+A recreational vehicle, not to be confused with vehicular recreation.
+RV also means an internal Reference Value of the type a L</scalar> can
+hold. See also L</IV> and L</NV> if you're not confused yet.
+
+=item rvalue
+
+A L</value> that you might find on the right side of an
+L</assignment>. See also L</lvalue>.
+
+=back
+
+=head2 S
+
+=over 4
+
+=item scalar
+
+A simple, singular value; a number, L</string>, or L</reference>.
+
+=item scalar context
+
+The situation in which an L</expression> is expected by its
+surroundings (the code calling it) to return a single L</value> rather
+than a L</list> of values. See also L</context> and L</list context>.
+A scalar context sometimes imposes additional constraints on the
+return value--see L</string context> and L</numeric context>.
+Sometimes we talk about a L</Boolean context> inside conditionals, but
+this imposes no additional constraints, since any scalar value,
+whether numeric or L</string>, is already true or false.
+
+=item scalar literal
+
+A number or quoted L</string>--an actual L</value> in the text of your
+program, as opposed to a L</variable>.
+
+=item scalar value
+
+A value that happens to be a L</scalar> as opposed to a L</list>.
+
+=item scalar variable
+
+A L</variable> prefixed with C<$> that holds a single value.
+
+=item scope
+
+How far away you can see a variable from, looking through one. Perl
+has two visibility mechanisms: it does L</dynamic scoping> of
+L<local|perlfunc/local> L<variables|/variable>, meaning that the rest
+of the L</block>, and any L<subroutines|/subroutine> that are called
+by the rest of the block, can see the variables that are local to the
+block. Perl does L</lexical scoping> of L<my|perlfunc/my> variables,
+meaning that the rest of the block can see the variable, but other
+subroutines called by the block I<cannot> see the variable.
+
+=item scratchpad
+
+The area in which a particular invocation of a particular file or
+subroutine keeps some of its temporary values, including any lexically
+scoped variables.
+
+=item script
+
+A text L</file> that is a program intended to be L<executed|/execute>
+directly rather than L<compiled|/compiler> to another form of file
+before execution. Also, in the context of L</Unicode>, a writing
+system for a particular language or group of languages, such as Greek,
+Bengali, or Klingon.
+
+=item script kiddie
+
+A L</cracker> who is not a L</hacker>, but knows just enough to run
+canned scripts. A cargo-cult programmer.
+
+=item sed
+
+A venerable Stream EDitor from which Perl derives some of its ideas.
+
+=item semaphore
+
+A fancy kind of interlock that prevents multiple L<threads|/thread> or
+L<processes|/process> from using up the same resources simultaneously.
+
+=item separator
+
+A L</character> or L</string> that keeps two surrounding strings from
+being confused with each other. The L<split|perlfunc/split> function
+works on separators. Not to be confused with L<delimiters|/delimiter>
+or L<terminators|/terminator>. The "or" in the previous sentence
+separated the two alternatives.
+
+=item serialization
+
+Putting a fancy L</data structure> into linear order so that it can be
+stored as a L</string> in a disk file or database or sent through a
+L</pipe>. Also called marshalling.
+
+=item server
+
+In networking, a L</process> that either advertises a L</service> or
+just hangs around at a known location and waits for L<clients|/client>
+who need service to get in touch with it.
+
+=item service
+
+Something you do for someone else to make them happy, like giving them
+the time of day (or of their life). On some machines, well-known
+services are listed by the L<getservent|perlfunc/getservent> function.
+
+=item setgid
+
+Same as L</setuid>, only having to do with giving away L</group>
+privileges.
+
+=item setuid
+
+Said of a program that runs with the privileges of its L</owner>
+rather than (as is usually the case) the privileges of whoever is
+running it. Also describes the bit in the mode word (L</permission
+bits>) that controls the feature. This bit must be explicitly set by
+the owner to enable this feature, and the program must be carefully
+written not to give away more privileges than it ought to.
+
+=item shared memory
+
+A piece of L</memory> accessible by two different
+L<processes|/process> who otherwise would not see each other's memory.
+
+=item shebang
+
+Irish for the whole McGillicuddy. In Perl culture, a portmanteau of
+"sharp" and "bang", meaning the C<#!> sequence that tells the system
+where to find the interpreter.
+
+=item shell
+
+A L</command>-line L</interpreter>. The program that interactively
+gives you a prompt, accepts one or more L<lines|/line> of input, and
+executes the programs you mentioned, feeding each of them their proper
+L<arguments|/argument> and input data. Shells can also execute
+scripts containing such commands. Under Unix, typical shells include
+the Bourne shell (I</bin/sh>), the C shell (I</bin/csh>), and the Korn
+shell (I</bin/ksh>). Perl is not strictly a shell because it's not
+interactive (although Perl programs can be interactive).
+
+=item side effects
+
+Something extra that happens when you evaluate an L</expression>.
+Nowadays it can refer to almost anything. For example, evaluating a
+simple assignment statement typically has the "side effect" of
+assigning a value to a variable. (And you thought assigning the value
+was your primary intent in the first place!) Likewise, assigning a
+value to the special variable C<$|> (C<$AUTOFLUSH>) has the side
+effect of forcing a flush after every L<write|perlfunc/write> or
+L<print|perlfunc/print> on the currently selected filehandle.
+
+=item signal
+
+A bolt out of the blue; that is, an event triggered by the
+L</operating system>, probably when you're least expecting it.
+
+=item signal handler
+
+A L</subroutine> that, instead of being content to be called in the
+normal fashion, sits around waiting for a bolt out of the blue before
+it will deign to L</execute>. Under Perl, bolts out of the blue are
+called signals, and you send them with the L<kill|perlfunc/kill>
+built-in. See L<perlvar/%SIG> and L<perlipc/Signals>.
+
+=item single inheritance
+
+The features you got from your mother, if she told you that you don't
+have a father. (See also L</inheritance> and L</multiple
+inheritance>.) In computer languages, the notion that
+L<classes|/class> reproduce asexually so that a given class can only
+have one direct ancestor or L</base class>. Perl supplies no such
+restriction, though you may certainly program Perl that way if you
+like.
+
+=item slice
+
+A selection of any number of L<elements|/element> from a L</list>,
+L</array>, or L</hash>.
+
+=item slurp
+
+To read an entire L</file> into a L</string> in one operation.
+
+=item socket
+
+An endpoint for network communication among multiple
+L<processes|/process> that works much like a telephone or a post
+office box. The most important thing about a socket is its L</network
+address> (like a phone number). Different kinds of sockets have
+different kinds of addresses--some look like filenames, and some
+don't.
+
+=item soft reference
+
+See L</symbolic reference>.
+
+=item source filter
+
+A special kind of L</module> that does L</preprocessing> on your
+script just before it gets to the L</tokener>.
+
+=item stack
+
+A device you can put things on the top of, and later take them back
+off in the opposite order in which you put them on. See L</LIFO>.
+
+=item standard
+
+Included in the official Perl distribution, as in a standard module, a
+standard tool, or a standard Perl L</manpage>.
+
+=item standard error
+
+The default output L</stream> for nasty remarks that don't belong in
+L</standard output>. Represented within a Perl program by the
+L</filehandle> L</STDERR>. You can use this stream explicitly, but the
+L<die|perlfunc/die> and L<warn|perlfunc/warn> built-ins write to your
+standard error stream automatically.
+
+=item standard I/O
+
+A standard C library for doing L<buffered|/buffer> input and output to
+the L</operating system>. (The "standard" of standard I/O is only
+marginally related to the "standard" of standard input and output.)
+In general, Perl relies on whatever implementation of standard I/O a
+given operating system supplies, so the buffering characteristics of a
+Perl program on one machine may not exactly match those on another
+machine. Normally this only influences efficiency, not semantics. If
+your standard I/O package is doing block buffering and you want it to
+L</flush> the buffer more often, just set the C<$|> variable to a true
+value.
+
+=item standard input
+
+The default input L</stream> for your program, which if possible
+shouldn't care where its data is coming from. Represented within a
+Perl program by the L</filehandle> L</STDIN>.
+
+=item standard output
+
+The default output L</stream> for your program, which if possible
+shouldn't care where its data is going. Represented within a Perl
+program by the L</filehandle> L</STDOUT>.
+
+=item stat structure
+
+A special internal spot in which Perl keeps the information about the
+last L</file> on which you requested information.
+
+=item statement
+
+A L</command> to the computer about what to do next, like a step in a
+recipe: "Add marmalade to batter and mix until mixed." A statement is
+distinguished from a L</declaration>, which doesn't tell the computer
+to do anything, but just to learn something.
+
+=item statement modifier
+
+A L</conditional> or L</loop> that you put after the L</statement>
+instead of before, if you know what we mean.
+
+=item static
+
+Varying slowly compared to something else. (Unfortunately, everything
+is relatively stable compared to something else, except for certain
+elementary particles, and we're not so sure about them.) In
+computers, where things are supposed to vary rapidly, "static" has a
+derogatory connotation, indicating a slightly dysfunctional
+L</variable>, L</subroutine>, or L</method>. In Perl culture, the
+word is politely avoided.
+
+=item static method
+
+No such thing. See L</class method>.
+
+=item static scoping
+
+No such thing. See L</lexical scoping>.
+
+=item static variable
+
+No such thing. Just use a L</lexical variable> in a scope larger than
+your L</subroutine>.
+
+=item status
+
+The L</value> returned to the parent L</process> when one of its child
+processes dies. This value is placed in the special variable C<$?>.
+Its upper eight L<bits|/bit> are the exit status of the defunct
+process, and its lower eight bits identify the signal (if any) that
+the process died from. On Unix systems, this status value is the same
+as the status word returned by I<wait>(2). See L<perlfunc/system>.
+
+=item STDERR
+
+See L</standard error>.
+
+=item STDIN
+
+See L</standard input>.
+
+=item STDIO
+
+See L</standard IE<sol>O>.
+
+=item STDOUT
+
+See L</standard output>.
+
+=item stream
+
+A flow of data into or out of a process as a steady sequence of bytes
+or characters, without the appearance of being broken up into packets.
+This is a kind of L</interface>--the underlying L</implementation> may
+well break your data up into separate packets for delivery, but this
+is hidden from you.
+
+=item string
+
+A sequence of characters such as "He said !@#*&%@#*?!". A string does
+not have to be entirely printable.
+
+=item string context
+
+The situation in which an expression is expected by its surroundings
+(the code calling it) to return a L</string>. See also L</context>
+and L</numeric context>.
+
+=item stringification
+
+The process of producing a L</string> representation of an abstract
+object.
+
+=item struct
+
+C keyword introducing a structure definition or name.
+
+=item structure
+
+See L</data structure>.
+
+=item subclass
+
+See L</derived class>.
+
+=item subpattern
+
+A component of a L</regular expression> pattern.
+
+=item subroutine
+
+A named or otherwise accessible piece of program that can be invoked
+from elsewhere in the program in order to accomplish some sub-goal of
+the program. A subroutine is often parameterized to accomplish
+different but related things depending on its input
+L<arguments|/argument>. If the subroutine returns a meaningful
+L</value>, it is also called a L</function>.
+
+=item subscript
+
+A L</value> that indicates the position of a particular L</array>
+L</element> in an array.
+
+=item substitution
+
+Changing parts of a string via the C<s///> operator. (We avoid use of
+this term to mean L</variable interpolation>.)
+
+=item substring
+
+A portion of a L</string>, starting at a certain L</character>
+position (L</offset>) and proceeding for a certain number of
+characters.
+
+=item superclass
+
+See L</base class>.
+
+=item superuser
+
+The person whom the L</operating system> will let do almost anything.
+Typically your system administrator or someone pretending to be your
+system administrator. On Unix systems, the L</root> user. On Windows
+systems, usually the Administrator user.
+
+=item SV
+
+Short for "scalar value". But within the Perl interpreter every
+L</referent> is treated as a member of a class derived from SV, in an
+object-oriented sort of way. Every L</value> inside Perl is passed
+around as a C language C<SV*> pointer. The SV L</struct> knows its
+own "referent type", and the code is smart enough (we hope) not to try
+to call a L</hash> function on a L</subroutine>.
+
+=item switch
+
+An option you give on a command line to influence the way your program
+works, usually introduced with a minus sign. The word is also used as
+a nickname for a L</switch statement>.
+
+=item switch cluster
+
+The combination of multiple command-line switches (e.g., B<-a -b -c>)
+into one switch (e.g., B<-abc>). Any switch with an additional
+L</argument> must be the last switch in a cluster.
+
+=item switch statement
+
+A program technique that lets you evaluate an L</expression> and then,
+based on the value of the expression, do a multiway branch to the
+appropriate piece of code for that value. Also called a "case
+structure", named after the similar Pascal construct. Most switch
+statements in Perl are spelled C<for>. See L<perlsyn/Basic BLOCKs and
+Switch Statements>.
+
+=item symbol
+
+Generally, any L</token> or L</metasymbol>. Often used more
+specifically to mean the sort of name you might find in a L</symbol
+table>.
+
+=item symbol table
+
+Where a L</compiler> remembers symbols. A program like Perl must
+somehow remember all the names of all the L<variables|/variable>,
+L<filehandles|/filehandle>, and L<subroutines|/subroutine> you've
+used. It does this by placing the names in a symbol table, which is
+implemented in Perl using a L</hash table>. There is a separate
+symbol table for each L</package> to give each package its own
+L</namespace>.
+
+=item symbolic debugger
+
+A program that lets you step through the L<execution|/execute> of your
+program, stopping or printing things out here and there to see whether
+anything has gone wrong, and if so, what. The "symbolic" part just
+means that you can talk to the debugger using the same symbols with
+which your program is written.
+
+=item symbolic link
+
+An alternate filename that points to the real L</filename>, which in
+turn points to the real L</file>. Whenever the L</operating system>
+is trying to parse a L</pathname> containing a symbolic link, it
+merely substitutes the new name and continues parsing.
+
+=item symbolic reference
+
+A variable whose value is the name of another variable or subroutine.
+By L<dereferencing|/dereference> the first variable, you can get at
+the second one. Symbolic references are illegal under L<use strict
+'refs'|strict/strict refs>.
+
+=item synchronous
+
+Programming in which the orderly sequence of events can be determined;
+that is, when things happen one after the other, not at the same time.
+
+=item syntactic sugar
+
+An alternative way of writing something more easily; a shortcut.
+
+=item syntax
+
+From Greek, "with-arrangement". How things (particularly symbols) are
+put together with each other.
+
+=item syntax tree
+
+An internal representation of your program wherein lower-level
+L<constructs|/construct> dangle off the higher-level constructs
+enclosing them.
+
+=item syscall
+
+A L</function> call directly to the L</operating system>. Many of the
+important subroutines and functions you use aren't direct system
+calls, but are built up in one or more layers above the system call
+level. In general, Perl programmers don't need to worry about the
+distinction. However, if you do happen to know which Perl functions
+are really syscalls, you can predict which of these will set the C<$!>
+(C<$ERRNO>) variable on failure. Unfortunately, beginning programmers
+often confusingly employ the term "system call" to mean what happens
+when you call the Perl L<system|perlfunc/system> function, which
+actually involves many syscalls. To avoid any confusion, we nearly
+always use say "syscall" for something you could call indirectly via
+Perl's L<syscall|perlfunc/syscall> function, and never for something
+you would call with Perl's L<system|perlfunc/system> function.
+
+=back
+
+=head2 T
+
+=over 4
+
+=item tainted
+
+Said of data derived from the grubby hands of a user and thus unsafe
+for a secure program to rely on. Perl does taint checks if you run a
+L</setuid> (or L</setgid>) program, or if you use the B<-T> switch.
+
+=item TCP
+
+Short for Transmission Control Protocol. A protocol wrapped around
+the Internet Protocol to make an unreliable packet transmission
+mechanism appear to the application program to be a reliable
+L</stream> of bytes. (Usually.)
+
+=item term
+
+Short for a "terminal", that is, a leaf node of a L</syntax tree>. A
+thing that functions grammatically as an L</operand> for the operators
+in an expression.
+
+=item terminator
+
+A L</character> or L</string> that marks the end of another string.
+The C<$/> variable contains the string that terminates a
+L<readline|perlfunc/readline> operation, which L<chomp|perlfunc/chomp>
+deletes from the end. Not to be confused with
+L<delimiters|/delimiter> or L<separators|/separator>. The period at
+the end of this sentence is a terminator.
+
+=item ternary
+
+An L</operator> taking three L<operands|/operand>. Sometimes
+pronounced L</trinary>.
+
+=item text
+
+A L</string> or L</file> containing primarily printable characters.
+
+=item thread
+
+Like a forked process, but without L</fork>'s inherent memory
+protection. A thread is lighter weight than a full process, in that a
+process could have multiple threads running around in it, all fighting
+over the same process's memory space unless steps are taken to protect
+threads from each other. See L<threads>.
+
+=item tie
+
+The bond between a magical variable and its implementation class. See
+L<perlfunc/tie> and L<perltie>.
+
+=item TMTOWTDI
+
+There's More Than One Way To Do It, the Perl Motto. The notion that
+there can be more than one valid path to solving a programming problem
+in context. (This doesn't mean that more ways are always better or
+that all possible paths are equally desirable--just that there need
+not be One True Way.) Pronounced TimToady.
+
+=item token
+
+A morpheme in a programming language, the smallest unit of text with
+semantic significance.
+
+=item tokener
+
+A module that breaks a program text into a sequence of
+L<tokens|/token> for later analysis by a parser.
+
+=item tokenizing
+
+Splitting up a program text into L<tokens|/token>. Also known as
+"lexing", in which case you get "lexemes" instead of tokens.
+
+=item toolbox approach
+
+The notion that, with a complete set of simple tools that work well
+together, you can build almost anything you want. Which is fine if
+you're assembling a tricycle, but if you're building a defranishizing
+comboflux regurgalator, you really want your own machine shop in which
+to build special tools. Perl is sort of a machine shop.
+
+=item transliterate
+
+To turn one string representation into another by mapping each
+character of the source string to its corresponding character in the
+result string. See
+L<perlop/trE<sol>SEARCHLISTE<sol>REPLACEMENTLISTE<sol>cds>.
+
+=item trigger
+
+An event that causes a L</handler> to be run.
+
+=item trinary
+
+Not a stellar system with three stars, but an L</operator> taking
+three L<operands|/operand>. Sometimes pronounced L</ternary>.
+
+=item troff
+
+A venerable typesetting language from which Perl derives the name of
+its C<$%> variable and which is secretly used in the production of
+Camel books.
+
+=item true
+
+Any scalar value that doesn't evaluate to 0 or C<"">.
+
+=item truncating
+
+Emptying a file of existing contents, either automatically when
+opening a file for writing or explicitly via the
+L<truncate|perlfunc/truncate> function.
+
+=item type
+
+See L</data type> and L</class>.
+
+=item type casting
+
+Converting data from one type to another. C permits this. Perl does
+not need it. Nor want it.
+
+=item typed lexical
+
+A L</lexical variable> that is declared with a L</class> type: C<my
+Pony $bill>.
+
+=item typedef
+
+A type definition in the C language.
+
+=item typeglob
+
+Use of a single identifier, prefixed with C<*>. For example, C<*name>
+stands for any or all of C<$name>, C<@name>, C<%name>, C<&name>, or
+just C<name>. How you use it determines whether it is interpreted as
+all or only one of them. See L<perldata/Typeglobs and Filehandles>.
+
+=item typemap
+
+A description of how C types may be transformed to and from Perl types
+within an L</extension> module written in L</XS>.
+
+=back
+
+=head2 U
+
+=over 4
+
+=item UDP
+
+User Datagram Protocol, the typical way to send L<datagrams|/datagram>
+over the Internet.
+
+=item UID
+
+A user ID. Often used in the context of L</file> or L</process>
+ownership.
+
+=item umask
+
+A mask of those L</permission bits> that should be forced off when
+creating files or directories, in order to establish a policy of whom
+you'll ordinarily deny access to. See the L<umask|perlfunc/umask>
+function.
+
+=item unary operator
+
+An operator with only one L</operand>, like C<!> or
+L<chdir|perlfunc/chdir>. Unary operators are usually prefix
+operators; that is, they precede their operand. The C<++> and C<-->
+operators can be either prefix or postfix. (Their position I<does>
+change their meanings.)
+
+=item Unicode
+
+A character set comprising all the major character sets of the world,
+more or less. See L<perlunicode> and L<http://www.unicode.org>.
+
+=item Unix
+
+A very large and constantly evolving language with several alternative
+and largely incompatible syntaxes, in which anyone can define anything
+any way they choose, and usually do. Speakers of this language think
+it's easy to learn because it's so easily twisted to one's own ends,
+but dialectical differences make tribal intercommunication nearly
+impossible, and travelers are often reduced to a pidgin-like subset of
+the language. To be universally understood, a Unix shell programmer
+must spend years of study in the art. Many have abandoned this
+discipline and now communicate via an Esperanto-like language called
+Perl.
+
+In ancient times, Unix was also used to refer to some code that a
+couple of people at Bell Labs wrote to make use of a PDP-7 computer
+that wasn't doing much of anything else at the time.
+
+=back
+
+=head2 V
+
+=over 4
+
+=item value
+
+An actual piece of data, in contrast to all the variables, references,
+keys, indexes, operators, and whatnot that you need to access the
+value.
+
+=item variable
+
+A named storage location that can hold any of various kinds of
+L</value>, as your program sees fit.
+
+=item variable interpolation
+
+The L</interpolation> of a scalar or array variable into a string.
+
+=item variadic
+
+Said of a L</function> that happily receives an indeterminate number
+of L</actual arguments>.
+
+=item vector
+
+Mathematical jargon for a list of L<scalar values|/scalar value>.
+
+=item virtual
+
+Providing the appearance of something without the reality, as in:
+virtual memory is not real memory. (See also L</memory>.) The
+opposite of "virtual" is "transparent", which means providing the
+reality of something without the appearance, as in: Perl handles the
+variable-length UTF-8 character encoding transparently.
+
+=item void context
+
+A form of L</scalar context> in which an L</expression> is not
+expected to return any L</value> at all and is evaluated for its
+L</side effects> alone.
+
+=item v-string
+
+A "version" or "vector" L</string> specified with a C<v> followed by a
+series of decimal integers in dot notation, for instance,
+C<v1.20.300.4000>. Each number turns into a L</character> with the
+specified ordinal value. (The C<v> is optional when there are at
+least three integers.)
+
+=back
+
+=head2 W
+
+=over 4
+
+=item warning
+
+A message printed to the L</STDERR> stream to the effect that something
+might be wrong but isn't worth blowing up over. See L<perlfunc/warn>
+and the L<warnings> pragma.
+
+=item watch expression
+
+An expression which, when its value changes, causes a breakpoint in
+the Perl debugger.
+
+=item whitespace
+
+A L</character> that moves your cursor but doesn't otherwise put
+anything on your screen. Typically refers to any of: space, tab, line
+feed, carriage return, or form feed.
+
+=item word
+
+In normal "computerese", the piece of data of the size most
+efficiently handled by your computer, typically 32 bits or so, give or
+take a few powers of 2. In Perl culture, it more often refers to an
+alphanumeric L</identifier> (including underscores), or to a string of
+nonwhitespace L<characters|/character> bounded by whitespace or string
+boundaries.
+
+=item working directory
+
+Your current L</directory>, from which relative pathnames are
+interpreted by the L</operating system>. The operating system knows
+your current directory because you told it with a
+L<chdir|perlfunc/chdir> or because you started out in the place where
+your parent L</process> was when you were born.
+
+=item wrapper
+
+A program or subroutine that runs some other program or subroutine for
+you, modifying some of its input or output to better suit your
+purposes.
+
+=item WYSIWYG
+
+What You See Is What You Get. Usually used when something that
+appears on the screen matches how it will eventually look, like Perl's
+L<format|perlfunc/format> declarations. Also used to mean the
+opposite of magic because everything works exactly as it appears, as
+in the three-argument form of L<open|perlfunc/open>.
+
+=back
+
+=head2 X
+
+=over 4
+
+=item XS
+
+An extraordinarily exported, expeditiously excellent, expressly
+eXternal Subroutine, executed in existing C or C++ or in an exciting
+new extension language called (exasperatingly) XS. Examine L<perlxs>
+for the exact explanation or L<perlxstut> for an exemplary unexacting
+one.
+
+=item XSUB
+
+An external L</subroutine> defined in L</XS>.
+
+=back
+
+=head2 Y
+
+=over 4
+
+=item yacc
+
+Yet Another Compiler Compiler. A parser generator without which Perl
+probably would not have existed. See the file I<perly.y> in the Perl
+source distribution.
+
+=back
+
+=head2 Z
+
+=over 4
+
+=item zero width
+
+A subpattern L</assertion> matching the L</null string> between
+L<characters|/character>.
+
+=item zombie
+
+A process that has died (exited) but whose parent has not yet received
+proper notification of its demise by virtue of having called
+L<wait|perlfunc/wait> or L<waitpid|perlfunc/waitpid>. If you
+L<fork|perlfunc/fork>, you must clean up after your child processes
+when they exit, or else the process table will fill up and your system
+administrator will Not Be Happy with you.
+
+=back
+
+=head1 AUTHOR AND COPYRIGHT
+
+Based on the Glossary of Programming Perl, Third Edition,
+by Larry Wall, Tom Christiansen & Jon Orwant.
+Copyright (c) 2000, 1996, 1991 O'Reilly Media, Inc.
+This document may be distributed under the same terms as Perl itself.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlgpl.pod b/Master/tlpkg/tlperl/lib/pods/perlgpl.pod
new file mode 100644
index 00000000000..de1791a95a8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlgpl.pod
@@ -0,0 +1,287 @@
+
+=head1 NAME
+
+perlgpl - the GNU General Public License, version 1
+
+=head1 SYNOPSIS
+
+ You can refer to this document in Pod via "L<perlgpl>"
+ Or you can see this document by entering "perldoc perlgpl"
+
+=head1 DESCRIPTION
+
+Perl is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+ a) the GNU General Public License as published by the Free
+ Software Foundation; either version 1, or (at your option) any
+ later version, or
+
+ b) the "Artistic License" which comes with this Kit.
+
+This is the B<"GNU General Public License, version 1">.
+It's here so that modules, programs, etc., that want to declare
+this as their distribution license can link to it.
+
+For the Perl Artistic License, see L<perlartistic>.
+
+=cut
+
+# Because the following document's language disallows "changing"
+# it, we haven't gone thru and prettied it up with =item's or
+# anything. It's good enough the way it is.
+
+=head1 GNU GENERAL PUBLIC LICENSE
+
+ GNU GENERAL PUBLIC LICENSE
+ Version 1, February 1989
+
+ Copyright (C) 1989 Free Software Foundation, Inc.
+ 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The license agreements of most software companies try to keep users
+ at the mercy of those companies. By contrast, our General Public
+ License is intended to guarantee your freedom to share and change free
+ software--to make sure the software is free for all its users. The
+ General Public License applies to the Free Software Foundation's
+ software and to any other program whose authors commit to using it.
+ You can use it for your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+ price. Specifically, the General Public License is designed to make
+ sure that you have the freedom to give away or sell copies of free
+ software, that you receive source code or can get it if you want it,
+ that you can change the software or use pieces of it in new free
+ programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+ anyone to deny you these rights or to ask you to surrender the rights.
+ These restrictions translate to certain responsibilities for you if you
+ distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of a such a program, whether
+ gratis or for a fee, you must give the recipients all the rights that
+ you have. You must make sure that they, too, receive or can get the
+ source code. And you must tell them their rights.
+
+ We protect your rights with two steps: (1) copyright the software, and
+ (2) offer you this license which gives you legal permission to copy,
+ distribute and/or modify the software.
+
+ Also, for each author's protection and ours, we want to make certain
+ that everyone understands that there is no warranty for this free
+ software. If the software is modified by someone else and passed on, we
+ want its recipients to know that what they have is not the original, so
+ that any problems introduced by others will not reflect on the original
+ authors' reputations.
+
+ The precise terms and conditions for copying, distribution and
+ modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License Agreement applies to any program or other work which
+ contains a notice placed by the copyright holder saying it may be
+ distributed under the terms of this General Public License. The
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+ licensee is addressed as "you".
+
+ 1. You may copy and distribute verbatim copies of the Program's source
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+ appropriately publish on each copy an appropriate copyright notice and
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+ General Public License and to the absence of any warranty; and give any
+ other recipients of the Program a copy of this General Public License
+ along with the Program. You may charge a fee for the physical act of
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+
+ 2. You may modify your copy or copies of the Program or any portion of
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+ 1 above, provided that you also do the following:
+
+ a) cause the modified files to carry prominent notices stating that
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+ third parties, at your option).
+
+ c) If the modified program normally reads commands interactively when
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+ 3. You may copy and distribute the Program (or a portion or derivative of
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+
+ 4. You may not copy, modify, sublicense, distribute or transfer the
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+ the Program is void, and will automatically terminate your rights to use
+ the Program under this License. However, parties who have received
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+
+ 5. By copying, distributing or modifying the Program (or any work based
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+
+ 6. Each time you redistribute the Program (or any work based on the
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+ recipients' exercise of the rights granted herein.
+
+ 7. The Free Software Foundation may publish revised and/or new versions
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+ address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the Program
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+ Foundation.
+
+ 8. If you wish to incorporate parts of the Program into other free
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+
+ NO WARRANTY
+
+ 9. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
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+
+ 10. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+ REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+ INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+ OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+ TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+ YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+ PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGES.
+
+ END OF TERMS AND CONDITIONS
+
+ Appendix: How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+ possible use to humanity, the best way to achieve this is to make it
+ free software which everyone can redistribute and change under these
+ terms.
+
+ To do so, attach the following notices to the program. It is safest to
+ attach them to the start of each source file to most effectively convey
+ the exclusion of warranty; and each file should have at least the
+ "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) 19yy <name of author>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 1, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+
+ Also add information on how to contact you by electronic and paper mail.
+
+ If the program is interactive, make it output a short notice like this
+ when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) 19xx name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+ The hypothetical commands `show w' and `show c' should show the
+ appropriate parts of the General Public License. Of course, the
+ commands you use may be called something other than `show w' and `show
+ c'; they could even be mouse-clicks or menu items--whatever suits your
+ program.
+
+ You should also get your employer (if you work as a programmer) or your
+ school, if any, to sign a "copyright disclaimer" for the program, if
+ necessary. Here a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright interest in the
+ program `Gnomovision' (a program to direct compilers to make passes
+ at assemblers) written by James Hacker.
+
+ <signature of Ty Coon>, 1 April 1989
+ Ty Coon, President of Vice
+
+ That's all there is to it!
+
+=cut
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlguts.pod b/Master/tlpkg/tlperl/lib/pods/perlguts.pod
new file mode 100644
index 00000000000..b6cec65bbbb
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlguts.pod
@@ -0,0 +1,2674 @@
+=head1 NAME
+
+perlguts - Introduction to the Perl API
+
+=head1 DESCRIPTION
+
+This document attempts to describe how to use the Perl API, as well as
+to provide some info on the basic workings of the Perl core. It is far
+from complete and probably contains many errors. Please refer any
+questions or comments to the author below.
+
+=head1 Variables
+
+=head2 Datatypes
+
+Perl has three typedefs that handle Perl's three main data types:
+
+ SV Scalar Value
+ AV Array Value
+ HV Hash Value
+
+Each typedef has specific routines that manipulate the various data types.
+
+=head2 What is an "IV"?
+
+Perl uses a special typedef IV which is a simple signed integer type that is
+guaranteed to be large enough to hold a pointer (as well as an integer).
+Additionally, there is the UV, which is simply an unsigned IV.
+
+Perl also uses two special typedefs, I32 and I16, which will always be at
+least 32-bits and 16-bits long, respectively. (Again, there are U32 and U16,
+as well.) They will usually be exactly 32 and 16 bits long, but on Crays
+they will both be 64 bits.
+
+=head2 Working with SVs
+
+An SV can be created and loaded with one command. There are five types of
+values that can be loaded: an integer value (IV), an unsigned integer
+value (UV), a double (NV), a string (PV), and another scalar (SV).
+
+The seven routines are:
+
+ SV* newSViv(IV);
+ SV* newSVuv(UV);
+ SV* newSVnv(double);
+ SV* newSVpv(const char*, STRLEN);
+ SV* newSVpvn(const char*, STRLEN);
+ SV* newSVpvf(const char*, ...);
+ SV* newSVsv(SV*);
+
+C<STRLEN> is an integer type (Size_t, usually defined as size_t in
+F<config.h>) guaranteed to be large enough to represent the size of
+any string that perl can handle.
+
+In the unlikely case of a SV requiring more complex initialisation, you
+can create an empty SV with newSV(len). If C<len> is 0 an empty SV of
+type NULL is returned, else an SV of type PV is returned with len + 1 (for
+the NUL) bytes of storage allocated, accessible via SvPVX. In both cases
+the SV has value undef.
+
+ SV *sv = newSV(0); /* no storage allocated */
+ SV *sv = newSV(10); /* 10 (+1) bytes of uninitialised storage allocated */
+
+To change the value of an I<already-existing> SV, there are eight routines:
+
+ void sv_setiv(SV*, IV);
+ void sv_setuv(SV*, UV);
+ void sv_setnv(SV*, double);
+ void sv_setpv(SV*, const char*);
+ void sv_setpvn(SV*, const char*, STRLEN)
+ void sv_setpvf(SV*, const char*, ...);
+ void sv_vsetpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool *);
+ void sv_setsv(SV*, SV*);
+
+Notice that you can choose to specify the length of the string to be
+assigned by using C<sv_setpvn>, C<newSVpvn>, or C<newSVpv>, or you may
+allow Perl to calculate the length by using C<sv_setpv> or by specifying
+0 as the second argument to C<newSVpv>. Be warned, though, that Perl will
+determine the string's length by using C<strlen>, which depends on the
+string terminating with a NUL character.
+
+The arguments of C<sv_setpvf> are processed like C<sprintf>, and the
+formatted output becomes the value.
+
+C<sv_vsetpvfn> is an analogue of C<vsprintf>, but it allows you to specify
+either a pointer to a variable argument list or the address and length of
+an array of SVs. The last argument points to a boolean; on return, if that
+boolean is true, then locale-specific information has been used to format
+the string, and the string's contents are therefore untrustworthy (see
+L<perlsec>). This pointer may be NULL if that information is not
+important. Note that this function requires you to specify the length of
+the format.
+
+The C<sv_set*()> functions are not generic enough to operate on values
+that have "magic". See L<Magic Virtual Tables> later in this document.
+
+All SVs that contain strings should be terminated with a NUL character.
+If it is not NUL-terminated there is a risk of
+core dumps and corruptions from code which passes the string to C
+functions or system calls which expect a NUL-terminated string.
+Perl's own functions typically add a trailing NUL for this reason.
+Nevertheless, you should be very careful when you pass a string stored
+in an SV to a C function or system call.
+
+To access the actual value that an SV points to, you can use the macros:
+
+ SvIV(SV*)
+ SvUV(SV*)
+ SvNV(SV*)
+ SvPV(SV*, STRLEN len)
+ SvPV_nolen(SV*)
+
+which will automatically coerce the actual scalar type into an IV, UV, double,
+or string.
+
+In the C<SvPV> macro, the length of the string returned is placed into the
+variable C<len> (this is a macro, so you do I<not> use C<&len>). If you do
+not care what the length of the data is, use the C<SvPV_nolen> macro.
+Historically the C<SvPV> macro with the global variable C<PL_na> has been
+used in this case. But that can be quite inefficient because C<PL_na> must
+be accessed in thread-local storage in threaded Perl. In any case, remember
+that Perl allows arbitrary strings of data that may both contain NULs and
+might not be terminated by a NUL.
+
+Also remember that C doesn't allow you to safely say C<foo(SvPV(s, len),
+len);>. It might work with your compiler, but it won't work for everyone.
+Break this sort of statement up into separate assignments:
+
+ SV *s;
+ STRLEN len;
+ char * ptr;
+ ptr = SvPV(s, len);
+ foo(ptr, len);
+
+If you want to know if the scalar value is TRUE, you can use:
+
+ SvTRUE(SV*)
+
+Although Perl will automatically grow strings for you, if you need to force
+Perl to allocate more memory for your SV, you can use the macro
+
+ SvGROW(SV*, STRLEN newlen)
+
+which will determine if more memory needs to be allocated. If so, it will
+call the function C<sv_grow>. Note that C<SvGROW> can only increase, not
+decrease, the allocated memory of an SV and that it does not automatically
+add a byte for the a trailing NUL (perl's own string functions typically do
+C<SvGROW(sv, len + 1)>).
+
+If you have an SV and want to know what kind of data Perl thinks is stored
+in it, you can use the following macros to check the type of SV you have.
+
+ SvIOK(SV*)
+ SvNOK(SV*)
+ SvPOK(SV*)
+
+You can get and set the current length of the string stored in an SV with
+the following macros:
+
+ SvCUR(SV*)
+ SvCUR_set(SV*, I32 val)
+
+You can also get a pointer to the end of the string stored in the SV
+with the macro:
+
+ SvEND(SV*)
+
+But note that these last three macros are valid only if C<SvPOK()> is true.
+
+If you want to append something to the end of string stored in an C<SV*>,
+you can use the following functions:
+
+ void sv_catpv(SV*, const char*);
+ void sv_catpvn(SV*, const char*, STRLEN);
+ void sv_catpvf(SV*, const char*, ...);
+ void sv_vcatpvfn(SV*, const char*, STRLEN, va_list *, SV **, I32, bool);
+ void sv_catsv(SV*, SV*);
+
+The first function calculates the length of the string to be appended by
+using C<strlen>. In the second, you specify the length of the string
+yourself. The third function processes its arguments like C<sprintf> and
+appends the formatted output. The fourth function works like C<vsprintf>.
+You can specify the address and length of an array of SVs instead of the
+va_list argument. The fifth function extends the string stored in the first
+SV with the string stored in the second SV. It also forces the second SV
+to be interpreted as a string.
+
+The C<sv_cat*()> functions are not generic enough to operate on values that
+have "magic". See L<Magic Virtual Tables> later in this document.
+
+If you know the name of a scalar variable, you can get a pointer to its SV
+by using the following:
+
+ SV* get_sv("package::varname", 0);
+
+This returns NULL if the variable does not exist.
+
+If you want to know if this variable (or any other SV) is actually C<defined>,
+you can call:
+
+ SvOK(SV*)
+
+The scalar C<undef> value is stored in an SV instance called C<PL_sv_undef>.
+
+Its address can be used whenever an C<SV*> is needed. Make sure that
+you don't try to compare a random sv with C<&PL_sv_undef>. For example
+when interfacing Perl code, it'll work correctly for:
+
+ foo(undef);
+
+But won't work when called as:
+
+ $x = undef;
+ foo($x);
+
+So to repeat always use SvOK() to check whether an sv is defined.
+
+Also you have to be careful when using C<&PL_sv_undef> as a value in
+AVs or HVs (see L<AVs, HVs and undefined values>).
+
+There are also the two values C<PL_sv_yes> and C<PL_sv_no>, which contain
+boolean TRUE and FALSE values, respectively. Like C<PL_sv_undef>, their
+addresses can be used whenever an C<SV*> is needed.
+
+Do not be fooled into thinking that C<(SV *) 0> is the same as C<&PL_sv_undef>.
+Take this code:
+
+ SV* sv = (SV*) 0;
+ if (I-am-to-return-a-real-value) {
+ sv = sv_2mortal(newSViv(42));
+ }
+ sv_setsv(ST(0), sv);
+
+This code tries to return a new SV (which contains the value 42) if it should
+return a real value, or undef otherwise. Instead it has returned a NULL
+pointer which, somewhere down the line, will cause a segmentation violation,
+bus error, or just weird results. Change the zero to C<&PL_sv_undef> in the
+first line and all will be well.
+
+To free an SV that you've created, call C<SvREFCNT_dec(SV*)>. Normally this
+call is not necessary (see L<Reference Counts and Mortality>).
+
+=head2 Offsets
+
+Perl provides the function C<sv_chop> to efficiently remove characters
+from the beginning of a string; you give it an SV and a pointer to
+somewhere inside the PV, and it discards everything before the
+pointer. The efficiency comes by means of a little hack: instead of
+actually removing the characters, C<sv_chop> sets the flag C<OOK>
+(offset OK) to signal to other functions that the offset hack is in
+effect, and it puts the number of bytes chopped off into the IV field
+of the SV. It then moves the PV pointer (called C<SvPVX>) forward that
+many bytes, and adjusts C<SvCUR> and C<SvLEN>.
+
+Hence, at this point, the start of the buffer that we allocated lives
+at C<SvPVX(sv) - SvIV(sv)> in memory and the PV pointer is pointing
+into the middle of this allocated storage.
+
+This is best demonstrated by example:
+
+ % ./perl -Ilib -MDevel::Peek -le '$a="12345"; $a=~s/.//; Dump($a)'
+ SV = PVIV(0x8128450) at 0x81340f0
+ REFCNT = 1
+ FLAGS = (POK,OOK,pPOK)
+ IV = 1 (OFFSET)
+ PV = 0x8135781 ( "1" . ) "2345"\0
+ CUR = 4
+ LEN = 5
+
+Here the number of bytes chopped off (1) is put into IV, and
+C<Devel::Peek::Dump> helpfully reminds us that this is an offset. The
+portion of the string between the "real" and the "fake" beginnings is
+shown in parentheses, and the values of C<SvCUR> and C<SvLEN> reflect
+the fake beginning, not the real one.
+
+Something similar to the offset hack is performed on AVs to enable
+efficient shifting and splicing off the beginning of the array; while
+C<AvARRAY> points to the first element in the array that is visible from
+Perl, C<AvALLOC> points to the real start of the C array. These are
+usually the same, but a C<shift> operation can be carried out by
+increasing C<AvARRAY> by one and decreasing C<AvFILL> and C<AvMAX>.
+Again, the location of the real start of the C array only comes into
+play when freeing the array. See C<av_shift> in F<av.c>.
+
+=head2 What's Really Stored in an SV?
+
+Recall that the usual method of determining the type of scalar you have is
+to use C<Sv*OK> macros. Because a scalar can be both a number and a string,
+usually these macros will always return TRUE and calling the C<Sv*V>
+macros will do the appropriate conversion of string to integer/double or
+integer/double to string.
+
+If you I<really> need to know if you have an integer, double, or string
+pointer in an SV, you can use the following three macros instead:
+
+ SvIOKp(SV*)
+ SvNOKp(SV*)
+ SvPOKp(SV*)
+
+These will tell you if you truly have an integer, double, or string pointer
+stored in your SV. The "p" stands for private.
+
+The are various ways in which the private and public flags may differ.
+For example, a tied SV may have a valid underlying value in the IV slot
+(so SvIOKp is true), but the data should be accessed via the FETCH
+routine rather than directly, so SvIOK is false. Another is when
+numeric conversion has occurred and precision has been lost: only the
+private flag is set on 'lossy' values. So when an NV is converted to an
+IV with loss, SvIOKp, SvNOKp and SvNOK will be set, while SvIOK wont be.
+
+In general, though, it's best to use the C<Sv*V> macros.
+
+=head2 Working with AVs
+
+There are two ways to create and load an AV. The first method creates an
+empty AV:
+
+ AV* newAV();
+
+The second method both creates the AV and initially populates it with SVs:
+
+ AV* av_make(I32 num, SV **ptr);
+
+The second argument points to an array containing C<num> C<SV*>'s. Once the
+AV has been created, the SVs can be destroyed, if so desired.
+
+Once the AV has been created, the following operations are possible on AVs:
+
+ void av_push(AV*, SV*);
+ SV* av_pop(AV*);
+ SV* av_shift(AV*);
+ void av_unshift(AV*, I32 num);
+
+These should be familiar operations, with the exception of C<av_unshift>.
+This routine adds C<num> elements at the front of the array with the C<undef>
+value. You must then use C<av_store> (described below) to assign values
+to these new elements.
+
+Here are some other functions:
+
+ I32 av_len(AV*);
+ SV** av_fetch(AV*, I32 key, I32 lval);
+ SV** av_store(AV*, I32 key, SV* val);
+
+The C<av_len> function returns the highest index value in array (just
+like $#array in Perl). If the array is empty, -1 is returned. The
+C<av_fetch> function returns the value at index C<key>, but if C<lval>
+is non-zero, then C<av_fetch> will store an undef value at that index.
+The C<av_store> function stores the value C<val> at index C<key>, and does
+not increment the reference count of C<val>. Thus the caller is responsible
+for taking care of that, and if C<av_store> returns NULL, the caller will
+have to decrement the reference count to avoid a memory leak. Note that
+C<av_fetch> and C<av_store> both return C<SV**>'s, not C<SV*>'s as their
+return value.
+
+ void av_clear(AV*);
+ void av_undef(AV*);
+ void av_extend(AV*, I32 key);
+
+The C<av_clear> function deletes all the elements in the AV* array, but
+does not actually delete the array itself. The C<av_undef> function will
+delete all the elements in the array plus the array itself. The
+C<av_extend> function extends the array so that it contains at least C<key+1>
+elements. If C<key+1> is less than the currently allocated length of the array,
+then nothing is done.
+
+If you know the name of an array variable, you can get a pointer to its AV
+by using the following:
+
+ AV* get_av("package::varname", 0);
+
+This returns NULL if the variable does not exist.
+
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use the array access functions on tied arrays.
+
+=head2 Working with HVs
+
+To create an HV, you use the following routine:
+
+ HV* newHV();
+
+Once the HV has been created, the following operations are possible on HVs:
+
+ SV** hv_store(HV*, const char* key, U32 klen, SV* val, U32 hash);
+ SV** hv_fetch(HV*, const char* key, U32 klen, I32 lval);
+
+The C<klen> parameter is the length of the key being passed in (Note that
+you cannot pass 0 in as a value of C<klen> to tell Perl to measure the
+length of the key). The C<val> argument contains the SV pointer to the
+scalar being stored, and C<hash> is the precomputed hash value (zero if
+you want C<hv_store> to calculate it for you). The C<lval> parameter
+indicates whether this fetch is actually a part of a store operation, in
+which case a new undefined value will be added to the HV with the supplied
+key and C<hv_fetch> will return as if the value had already existed.
+
+Remember that C<hv_store> and C<hv_fetch> return C<SV**>'s and not just
+C<SV*>. To access the scalar value, you must first dereference the return
+value. However, you should check to make sure that the return value is
+not NULL before dereferencing it.
+
+These two functions check if a hash table entry exists, and deletes it.
+
+ bool hv_exists(HV*, const char* key, U32 klen);
+ SV* hv_delete(HV*, const char* key, U32 klen, I32 flags);
+
+If C<flags> does not include the C<G_DISCARD> flag then C<hv_delete> will
+create and return a mortal copy of the deleted value.
+
+And more miscellaneous functions:
+
+ void hv_clear(HV*);
+ void hv_undef(HV*);
+
+Like their AV counterparts, C<hv_clear> deletes all the entries in the hash
+table but does not actually delete the hash table. The C<hv_undef> deletes
+both the entries and the hash table itself.
+
+Perl keeps the actual data in linked list of structures with a typedef of HE.
+These contain the actual key and value pointers (plus extra administrative
+overhead). The key is a string pointer; the value is an C<SV*>. However,
+once you have an C<HE*>, to get the actual key and value, use the routines
+specified below.
+
+ I32 hv_iterinit(HV*);
+ /* Prepares starting point to traverse hash table */
+ HE* hv_iternext(HV*);
+ /* Get the next entry, and return a pointer to a
+ structure that has both the key and value */
+ char* hv_iterkey(HE* entry, I32* retlen);
+ /* Get the key from an HE structure and also return
+ the length of the key string */
+ SV* hv_iterval(HV*, HE* entry);
+ /* Return an SV pointer to the value of the HE
+ structure */
+ SV* hv_iternextsv(HV*, char** key, I32* retlen);
+ /* This convenience routine combines hv_iternext,
+ hv_iterkey, and hv_iterval. The key and retlen
+ arguments are return values for the key and its
+ length. The value is returned in the SV* argument */
+
+If you know the name of a hash variable, you can get a pointer to its HV
+by using the following:
+
+ HV* get_hv("package::varname", 0);
+
+This returns NULL if the variable does not exist.
+
+The hash algorithm is defined in the C<PERL_HASH(hash, key, klen)> macro:
+
+ hash = 0;
+ while (klen--)
+ hash = (hash * 33) + *key++;
+ hash = hash + (hash >> 5); /* after 5.6 */
+
+The last step was added in version 5.6 to improve distribution of
+lower bits in the resulting hash value.
+
+See L<Understanding the Magic of Tied Hashes and Arrays> for more
+information on how to use the hash access functions on tied hashes.
+
+=head2 Hash API Extensions
+
+Beginning with version 5.004, the following functions are also supported:
+
+ HE* hv_fetch_ent (HV* tb, SV* key, I32 lval, U32 hash);
+ HE* hv_store_ent (HV* tb, SV* key, SV* val, U32 hash);
+
+ bool hv_exists_ent (HV* tb, SV* key, U32 hash);
+ SV* hv_delete_ent (HV* tb, SV* key, I32 flags, U32 hash);
+
+ SV* hv_iterkeysv (HE* entry);
+
+Note that these functions take C<SV*> keys, which simplifies writing
+of extension code that deals with hash structures. These functions
+also allow passing of C<SV*> keys to C<tie> functions without forcing
+you to stringify the keys (unlike the previous set of functions).
+
+They also return and accept whole hash entries (C<HE*>), making their
+use more efficient (since the hash number for a particular string
+doesn't have to be recomputed every time). See L<perlapi> for detailed
+descriptions.
+
+The following macros must always be used to access the contents of hash
+entries. Note that the arguments to these macros must be simple
+variables, since they may get evaluated more than once. See
+L<perlapi> for detailed descriptions of these macros.
+
+ HePV(HE* he, STRLEN len)
+ HeVAL(HE* he)
+ HeHASH(HE* he)
+ HeSVKEY(HE* he)
+ HeSVKEY_force(HE* he)
+ HeSVKEY_set(HE* he, SV* sv)
+
+These two lower level macros are defined, but must only be used when
+dealing with keys that are not C<SV*>s:
+
+ HeKEY(HE* he)
+ HeKLEN(HE* he)
+
+Note that both C<hv_store> and C<hv_store_ent> do not increment the
+reference count of the stored C<val>, which is the caller's responsibility.
+If these functions return a NULL value, the caller will usually have to
+decrement the reference count of C<val> to avoid a memory leak.
+
+=head2 AVs, HVs and undefined values
+
+Sometimes you have to store undefined values in AVs or HVs. Although
+this may be a rare case, it can be tricky. That's because you're
+used to using C<&PL_sv_undef> if you need an undefined SV.
+
+For example, intuition tells you that this XS code:
+
+ AV *av = newAV();
+ av_store( av, 0, &PL_sv_undef );
+
+is equivalent to this Perl code:
+
+ my @av;
+ $av[0] = undef;
+
+Unfortunately, this isn't true. AVs use C<&PL_sv_undef> as a marker
+for indicating that an array element has not yet been initialized.
+Thus, C<exists $av[0]> would be true for the above Perl code, but
+false for the array generated by the XS code.
+
+Other problems can occur when storing C<&PL_sv_undef> in HVs:
+
+ hv_store( hv, "key", 3, &PL_sv_undef, 0 );
+
+This will indeed make the value C<undef>, but if you try to modify
+the value of C<key>, you'll get the following error:
+
+ Modification of non-creatable hash value attempted
+
+In perl 5.8.0, C<&PL_sv_undef> was also used to mark placeholders
+in restricted hashes. This caused such hash entries not to appear
+when iterating over the hash or when checking for the keys
+with the C<hv_exists> function.
+
+You can run into similar problems when you store C<&PL_sv_true> or
+C<&PL_sv_false> into AVs or HVs. Trying to modify such elements
+will give you the following error:
+
+ Modification of a read-only value attempted
+
+To make a long story short, you can use the special variables
+C<&PL_sv_undef>, C<&PL_sv_true> and C<&PL_sv_false> with AVs and
+HVs, but you have to make sure you know what you're doing.
+
+Generally, if you want to store an undefined value in an AV
+or HV, you should not use C<&PL_sv_undef>, but rather create a
+new undefined value using the C<newSV> function, for example:
+
+ av_store( av, 42, newSV(0) );
+ hv_store( hv, "foo", 3, newSV(0), 0 );
+
+=head2 References
+
+References are a special type of scalar that point to other data types
+(including references).
+
+To create a reference, use either of the following functions:
+
+ SV* newRV_inc((SV*) thing);
+ SV* newRV_noinc((SV*) thing);
+
+The C<thing> argument can be any of an C<SV*>, C<AV*>, or C<HV*>. The
+functions are identical except that C<newRV_inc> increments the reference
+count of the C<thing>, while C<newRV_noinc> does not. For historical
+reasons, C<newRV> is a synonym for C<newRV_inc>.
+
+Once you have a reference, you can use the following macro to dereference
+the reference:
+
+ SvRV(SV*)
+
+then call the appropriate routines, casting the returned C<SV*> to either an
+C<AV*> or C<HV*>, if required.
+
+To determine if an SV is a reference, you can use the following macro:
+
+ SvROK(SV*)
+
+To discover what type of value the reference refers to, use the following
+macro and then check the return value.
+
+ SvTYPE(SvRV(SV*))
+
+The most useful types that will be returned are:
+
+ SVt_IV Scalar
+ SVt_NV Scalar
+ SVt_PV Scalar
+ SVt_RV Scalar
+ SVt_PVAV Array
+ SVt_PVHV Hash
+ SVt_PVCV Code
+ SVt_PVGV Glob (possible a file handle)
+ SVt_PVMG Blessed or Magical Scalar
+
+See the F<sv.h> header file for more details.
+
+=head2 Blessed References and Class Objects
+
+References are also used to support object-oriented programming. In perl's
+OO lexicon, an object is simply a reference that has been blessed into a
+package (or class). Once blessed, the programmer may now use the reference
+to access the various methods in the class.
+
+A reference can be blessed into a package with the following function:
+
+ SV* sv_bless(SV* sv, HV* stash);
+
+The C<sv> argument must be a reference value. The C<stash> argument
+specifies which class the reference will belong to. See
+L<Stashes and Globs> for information on converting class names into stashes.
+
+/* Still under construction */
+
+Upgrades rv to reference if not already one. Creates new SV for rv to
+point to. If C<classname> is non-null, the SV is blessed into the specified
+class. SV is returned.
+
+ SV* newSVrv(SV* rv, const char* classname);
+
+Copies integer, unsigned integer or double into an SV whose reference is C<rv>. SV is blessed
+if C<classname> is non-null.
+
+ SV* sv_setref_iv(SV* rv, const char* classname, IV iv);
+ SV* sv_setref_uv(SV* rv, const char* classname, UV uv);
+ SV* sv_setref_nv(SV* rv, const char* classname, NV iv);
+
+Copies the pointer value (I<the address, not the string!>) into an SV whose
+reference is rv. SV is blessed if C<classname> is non-null.
+
+ SV* sv_setref_pv(SV* rv, const char* classname, PV iv);
+
+Copies string into an SV whose reference is C<rv>. Set length to 0 to let
+Perl calculate the string length. SV is blessed if C<classname> is non-null.
+
+ SV* sv_setref_pvn(SV* rv, const char* classname, PV iv, STRLEN length);
+
+Tests whether the SV is blessed into the specified class. It does not
+check inheritance relationships.
+
+ int sv_isa(SV* sv, const char* name);
+
+Tests whether the SV is a reference to a blessed object.
+
+ int sv_isobject(SV* sv);
+
+Tests whether the SV is derived from the specified class. SV can be either
+a reference to a blessed object or a string containing a class name. This
+is the function implementing the C<UNIVERSAL::isa> functionality.
+
+ bool sv_derived_from(SV* sv, const char* name);
+
+To check if you've got an object derived from a specific class you have
+to write:
+
+ if (sv_isobject(sv) && sv_derived_from(sv, class)) { ... }
+
+=head2 Creating New Variables
+
+To create a new Perl variable with an undef value which can be accessed from
+your Perl script, use the following routines, depending on the variable type.
+
+ SV* get_sv("package::varname", GV_ADD);
+ AV* get_av("package::varname", GV_ADD);
+ HV* get_hv("package::varname", GV_ADD);
+
+Notice the use of TRUE as the second parameter. The new variable can now
+be set, using the routines appropriate to the data type.
+
+There are additional macros whose values may be bitwise OR'ed with the
+C<TRUE> argument to enable certain extra features. Those bits are:
+
+=over
+
+=item GV_ADDMULTI
+
+Marks the variable as multiply defined, thus preventing the:
+
+ Name <varname> used only once: possible typo
+
+warning.
+
+=item GV_ADDWARN
+
+Issues the warning:
+
+ Had to create <varname> unexpectedly
+
+if the variable did not exist before the function was called.
+
+=back
+
+If you do not specify a package name, the variable is created in the current
+package.
+
+=head2 Reference Counts and Mortality
+
+Perl uses a reference count-driven garbage collection mechanism. SVs,
+AVs, or HVs (xV for short in the following) start their life with a
+reference count of 1. If the reference count of an xV ever drops to 0,
+then it will be destroyed and its memory made available for reuse.
+
+This normally doesn't happen at the Perl level unless a variable is
+undef'ed or the last variable holding a reference to it is changed or
+overwritten. At the internal level, however, reference counts can be
+manipulated with the following macros:
+
+ int SvREFCNT(SV* sv);
+ SV* SvREFCNT_inc(SV* sv);
+ void SvREFCNT_dec(SV* sv);
+
+However, there is one other function which manipulates the reference
+count of its argument. The C<newRV_inc> function, you will recall,
+creates a reference to the specified argument. As a side effect,
+it increments the argument's reference count. If this is not what
+you want, use C<newRV_noinc> instead.
+
+For example, imagine you want to return a reference from an XSUB function.
+Inside the XSUB routine, you create an SV which initially has a reference
+count of one. Then you call C<newRV_inc>, passing it the just-created SV.
+This returns the reference as a new SV, but the reference count of the
+SV you passed to C<newRV_inc> has been incremented to two. Now you
+return the reference from the XSUB routine and forget about the SV.
+But Perl hasn't! Whenever the returned reference is destroyed, the
+reference count of the original SV is decreased to one and nothing happens.
+The SV will hang around without any way to access it until Perl itself
+terminates. This is a memory leak.
+
+The correct procedure, then, is to use C<newRV_noinc> instead of
+C<newRV_inc>. Then, if and when the last reference is destroyed,
+the reference count of the SV will go to zero and it will be destroyed,
+stopping any memory leak.
+
+There are some convenience functions available that can help with the
+destruction of xVs. These functions introduce the concept of "mortality".
+An xV that is mortal has had its reference count marked to be decremented,
+but not actually decremented, until "a short time later". Generally the
+term "short time later" means a single Perl statement, such as a call to
+an XSUB function. The actual determinant for when mortal xVs have their
+reference count decremented depends on two macros, SAVETMPS and FREETMPS.
+See L<perlcall> and L<perlxs> for more details on these macros.
+
+"Mortalization" then is at its simplest a deferred C<SvREFCNT_dec>.
+However, if you mortalize a variable twice, the reference count will
+later be decremented twice.
+
+"Mortal" SVs are mainly used for SVs that are placed on perl's stack.
+For example an SV which is created just to pass a number to a called sub
+is made mortal to have it cleaned up automatically when it's popped off
+the stack. Similarly, results returned by XSUBs (which are pushed on the
+stack) are often made mortal.
+
+To create a mortal variable, use the functions:
+
+ SV* sv_newmortal()
+ SV* sv_2mortal(SV*)
+ SV* sv_mortalcopy(SV*)
+
+The first call creates a mortal SV (with no value), the second converts an existing
+SV to a mortal SV (and thus defers a call to C<SvREFCNT_dec>), and the
+third creates a mortal copy of an existing SV.
+Because C<sv_newmortal> gives the new SV no value,it must normally be given one
+via C<sv_setpv>, C<sv_setiv>, etc. :
+
+ SV *tmp = sv_newmortal();
+ sv_setiv(tmp, an_integer);
+
+As that is multiple C statements it is quite common so see this idiom instead:
+
+ SV *tmp = sv_2mortal(newSViv(an_integer));
+
+
+You should be careful about creating mortal variables. Strange things
+can happen if you make the same value mortal within multiple contexts,
+or if you make a variable mortal multiple times. Thinking of "Mortalization"
+as deferred C<SvREFCNT_dec> should help to minimize such problems.
+For example if you are passing an SV which you I<know> has high enough REFCNT
+to survive its use on the stack you need not do any mortalization.
+If you are not sure then doing an C<SvREFCNT_inc> and C<sv_2mortal>, or
+making a C<sv_mortalcopy> is safer.
+
+The mortal routines are not just for SVs; AVs and HVs can be
+made mortal by passing their address (type-casted to C<SV*>) to the
+C<sv_2mortal> or C<sv_mortalcopy> routines.
+
+=head2 Stashes and Globs
+
+A B<stash> is a hash that contains all variables that are defined
+within a package. Each key of the stash is a symbol
+name (shared by all the different types of objects that have the same
+name), and each value in the hash table is a GV (Glob Value). This GV
+in turn contains references to the various objects of that name,
+including (but not limited to) the following:
+
+ Scalar Value
+ Array Value
+ Hash Value
+ I/O Handle
+ Format
+ Subroutine
+
+There is a single stash called C<PL_defstash> that holds the items that exist
+in the C<main> package. To get at the items in other packages, append the
+string "::" to the package name. The items in the C<Foo> package are in
+the stash C<Foo::> in PL_defstash. The items in the C<Bar::Baz> package are
+in the stash C<Baz::> in C<Bar::>'s stash.
+
+To get the stash pointer for a particular package, use the function:
+
+ HV* gv_stashpv(const char* name, I32 flags)
+ HV* gv_stashsv(SV*, I32 flags)
+
+The first function takes a literal string, the second uses the string stored
+in the SV. Remember that a stash is just a hash table, so you get back an
+C<HV*>. The C<flags> flag will create a new package if it is set to GV_ADD.
+
+The name that C<gv_stash*v> wants is the name of the package whose symbol table
+you want. The default package is called C<main>. If you have multiply nested
+packages, pass their names to C<gv_stash*v>, separated by C<::> as in the Perl
+language itself.
+
+Alternately, if you have an SV that is a blessed reference, you can find
+out the stash pointer by using:
+
+ HV* SvSTASH(SvRV(SV*));
+
+then use the following to get the package name itself:
+
+ char* HvNAME(HV* stash);
+
+If you need to bless or re-bless an object you can use the following
+function:
+
+ SV* sv_bless(SV*, HV* stash)
+
+where the first argument, an C<SV*>, must be a reference, and the second
+argument is a stash. The returned C<SV*> can now be used in the same way
+as any other SV.
+
+For more information on references and blessings, consult L<perlref>.
+
+=head2 Double-Typed SVs
+
+Scalar variables normally contain only one type of value, an integer,
+double, pointer, or reference. Perl will automatically convert the
+actual scalar data from the stored type into the requested type.
+
+Some scalar variables contain more than one type of scalar data. For
+example, the variable C<$!> contains either the numeric value of C<errno>
+or its string equivalent from either C<strerror> or C<sys_errlist[]>.
+
+To force multiple data values into an SV, you must do two things: use the
+C<sv_set*v> routines to add the additional scalar type, then set a flag
+so that Perl will believe it contains more than one type of data. The
+four macros to set the flags are:
+
+ SvIOK_on
+ SvNOK_on
+ SvPOK_on
+ SvROK_on
+
+The particular macro you must use depends on which C<sv_set*v> routine
+you called first. This is because every C<sv_set*v> routine turns on
+only the bit for the particular type of data being set, and turns off
+all the rest.
+
+For example, to create a new Perl variable called "dberror" that contains
+both the numeric and descriptive string error values, you could use the
+following code:
+
+ extern int dberror;
+ extern char *dberror_list;
+
+ SV* sv = get_sv("dberror", GV_ADD);
+ sv_setiv(sv, (IV) dberror);
+ sv_setpv(sv, dberror_list[dberror]);
+ SvIOK_on(sv);
+
+If the order of C<sv_setiv> and C<sv_setpv> had been reversed, then the
+macro C<SvPOK_on> would need to be called instead of C<SvIOK_on>.
+
+=head2 Magic Variables
+
+[This section still under construction. Ignore everything here. Post no
+bills. Everything not permitted is forbidden.]
+
+Any SV may be magical, that is, it has special features that a normal
+SV does not have. These features are stored in the SV structure in a
+linked list of C<struct magic>'s, typedef'ed to C<MAGIC>.
+
+ struct magic {
+ MAGIC* mg_moremagic;
+ MGVTBL* mg_virtual;
+ U16 mg_private;
+ char mg_type;
+ U8 mg_flags;
+ I32 mg_len;
+ SV* mg_obj;
+ char* mg_ptr;
+ };
+
+Note this is current as of patchlevel 0, and could change at any time.
+
+=head2 Assigning Magic
+
+Perl adds magic to an SV using the sv_magic function:
+
+ void sv_magic(SV* sv, SV* obj, int how, const char* name, I32 namlen);
+
+The C<sv> argument is a pointer to the SV that is to acquire a new magical
+feature.
+
+If C<sv> is not already magical, Perl uses the C<SvUPGRADE> macro to
+convert C<sv> to type C<SVt_PVMG>. Perl then continues by adding new magic
+to the beginning of the linked list of magical features. Any prior entry
+of the same type of magic is deleted. Note that this can be overridden,
+and multiple instances of the same type of magic can be associated with an
+SV.
+
+The C<name> and C<namlen> arguments are used to associate a string with
+the magic, typically the name of a variable. C<namlen> is stored in the
+C<mg_len> field and if C<name> is non-null then either a C<savepvn> copy of
+C<name> or C<name> itself is stored in the C<mg_ptr> field, depending on
+whether C<namlen> is greater than zero or equal to zero respectively. As a
+special case, if C<(name && namlen == HEf_SVKEY)> then C<name> is assumed
+to contain an C<SV*> and is stored as-is with its REFCNT incremented.
+
+The sv_magic function uses C<how> to determine which, if any, predefined
+"Magic Virtual Table" should be assigned to the C<mg_virtual> field.
+See the L<Magic Virtual Tables> section below. The C<how> argument is also
+stored in the C<mg_type> field. The value of C<how> should be chosen
+from the set of macros C<PERL_MAGIC_foo> found in F<perl.h>. Note that before
+these macros were added, Perl internals used to directly use character
+literals, so you may occasionally come across old code or documentation
+referring to 'U' magic rather than C<PERL_MAGIC_uvar> for example.
+
+The C<obj> argument is stored in the C<mg_obj> field of the C<MAGIC>
+structure. If it is not the same as the C<sv> argument, the reference
+count of the C<obj> object is incremented. If it is the same, or if
+the C<how> argument is C<PERL_MAGIC_arylen>, or if it is a NULL pointer,
+then C<obj> is merely stored, without the reference count being incremented.
+
+See also C<sv_magicext> in L<perlapi> for a more flexible way to add magic
+to an SV.
+
+There is also a function to add magic to an C<HV>:
+
+ void hv_magic(HV *hv, GV *gv, int how);
+
+This simply calls C<sv_magic> and coerces the C<gv> argument into an C<SV>.
+
+To remove the magic from an SV, call the function sv_unmagic:
+
+ void sv_unmagic(SV *sv, int type);
+
+The C<type> argument should be equal to the C<how> value when the C<SV>
+was initially made magical.
+
+=head2 Magic Virtual Tables
+
+The C<mg_virtual> field in the C<MAGIC> structure is a pointer to an
+C<MGVTBL>, which is a structure of function pointers and stands for
+"Magic Virtual Table" to handle the various operations that might be
+applied to that variable.
+
+The C<MGVTBL> has five (or sometimes eight) pointers to the following
+routine types:
+
+ int (*svt_get)(SV* sv, MAGIC* mg);
+ int (*svt_set)(SV* sv, MAGIC* mg);
+ U32 (*svt_len)(SV* sv, MAGIC* mg);
+ int (*svt_clear)(SV* sv, MAGIC* mg);
+ int (*svt_free)(SV* sv, MAGIC* mg);
+
+ int (*svt_copy)(SV *sv, MAGIC* mg, SV *nsv, const char *name, I32 namlen);
+ int (*svt_dup)(MAGIC *mg, CLONE_PARAMS *param);
+ int (*svt_local)(SV *nsv, MAGIC *mg);
+
+
+This MGVTBL structure is set at compile-time in F<perl.h> and there are
+currently 32 types. These different structures contain pointers to various
+routines that perform additional actions depending on which function is
+being called.
+
+ Function pointer Action taken
+ ---------------- ------------
+ svt_get Do something before the value of the SV is retrieved.
+ svt_set Do something after the SV is assigned a value.
+ svt_len Report on the SV's length.
+ svt_clear Clear something the SV represents.
+ svt_free Free any extra storage associated with the SV.
+
+ svt_copy copy tied variable magic to a tied element
+ svt_dup duplicate a magic structure during thread cloning
+ svt_local copy magic to local value during 'local'
+
+For instance, the MGVTBL structure called C<vtbl_sv> (which corresponds
+to an C<mg_type> of C<PERL_MAGIC_sv>) contains:
+
+ { magic_get, magic_set, magic_len, 0, 0 }
+
+Thus, when an SV is determined to be magical and of type C<PERL_MAGIC_sv>,
+if a get operation is being performed, the routine C<magic_get> is
+called. All the various routines for the various magical types begin
+with C<magic_>. NOTE: the magic routines are not considered part of
+the Perl API, and may not be exported by the Perl library.
+
+The last three slots are a recent addition, and for source code
+compatibility they are only checked for if one of the three flags
+MGf_COPY, MGf_DUP or MGf_LOCAL is set in mg_flags. This means that most
+code can continue declaring a vtable as a 5-element value. These three are
+currently used exclusively by the threading code, and are highly subject
+to change.
+
+The current kinds of Magic Virtual Tables are:
+
+ mg_type
+ (old-style char and macro) MGVTBL Type of magic
+ -------------------------- ------ -------------
+ \0 PERL_MAGIC_sv vtbl_sv Special scalar variable
+ A PERL_MAGIC_overload vtbl_amagic %OVERLOAD hash
+ a PERL_MAGIC_overload_elem vtbl_amagicelem %OVERLOAD hash element
+ c PERL_MAGIC_overload_table (none) Holds overload table (AMT)
+ on stash
+ B PERL_MAGIC_bm vtbl_bm Boyer-Moore (fast string search)
+ D PERL_MAGIC_regdata vtbl_regdata Regex match position data
+ (@+ and @- vars)
+ d PERL_MAGIC_regdatum vtbl_regdatum Regex match position data
+ element
+ E PERL_MAGIC_env vtbl_env %ENV hash
+ e PERL_MAGIC_envelem vtbl_envelem %ENV hash element
+ f PERL_MAGIC_fm vtbl_fm Formline ('compiled' format)
+ g PERL_MAGIC_regex_global vtbl_mglob m//g target / study()ed string
+ H PERL_MAGIC_hints vtbl_hints %^H hash
+ h PERL_MAGIC_hintselem vtbl_hintselem %^H hash element
+ I PERL_MAGIC_isa vtbl_isa @ISA array
+ i PERL_MAGIC_isaelem vtbl_isaelem @ISA array element
+ k PERL_MAGIC_nkeys vtbl_nkeys scalar(keys()) lvalue
+ L PERL_MAGIC_dbfile (none) Debugger %_<filename
+ l PERL_MAGIC_dbline vtbl_dbline Debugger %_<filename element
+ o PERL_MAGIC_collxfrm vtbl_collxfrm Locale collate transformation
+ P PERL_MAGIC_tied vtbl_pack Tied array or hash
+ p PERL_MAGIC_tiedelem vtbl_packelem Tied array or hash element
+ q PERL_MAGIC_tiedscalar vtbl_packelem Tied scalar or handle
+ r PERL_MAGIC_qr vtbl_qr precompiled qr// regex
+ S PERL_MAGIC_sig vtbl_sig %SIG hash
+ s PERL_MAGIC_sigelem vtbl_sigelem %SIG hash element
+ t PERL_MAGIC_taint vtbl_taint Taintedness
+ U PERL_MAGIC_uvar vtbl_uvar Available for use by extensions
+ v PERL_MAGIC_vec vtbl_vec vec() lvalue
+ V PERL_MAGIC_vstring (none) v-string scalars
+ w PERL_MAGIC_utf8 vtbl_utf8 UTF-8 length+offset cache
+ x PERL_MAGIC_substr vtbl_substr substr() lvalue
+ y PERL_MAGIC_defelem vtbl_defelem Shadow "foreach" iterator
+ variable / smart parameter
+ vivification
+ # PERL_MAGIC_arylen vtbl_arylen Array length ($#ary)
+ . PERL_MAGIC_pos vtbl_pos pos() lvalue
+ < PERL_MAGIC_backref vtbl_backref back pointer to a weak ref
+ ~ PERL_MAGIC_ext (none) Available for use by extensions
+ : PERL_MAGIC_symtab (none) hash used as symbol table
+ % PERL_MAGIC_rhash (none) hash used as restricted hash
+ @ PERL_MAGIC_arylen_p vtbl_arylen_p pointer to $#a from @a
+
+
+When an uppercase and lowercase letter both exist in the table, then the
+uppercase letter is typically used to represent some kind of composite type
+(a list or a hash), and the lowercase letter is used to represent an element
+of that composite type. Some internals code makes use of this case
+relationship. However, 'v' and 'V' (vec and v-string) are in no way related.
+
+The C<PERL_MAGIC_ext> and C<PERL_MAGIC_uvar> magic types are defined
+specifically for use by extensions and will not be used by perl itself.
+Extensions can use C<PERL_MAGIC_ext> magic to 'attach' private information
+to variables (typically objects). This is especially useful because
+there is no way for normal perl code to corrupt this private information
+(unlike using extra elements of a hash object).
+
+Similarly, C<PERL_MAGIC_uvar> magic can be used much like tie() to call a
+C function any time a scalar's value is used or changed. The C<MAGIC>'s
+C<mg_ptr> field points to a C<ufuncs> structure:
+
+ struct ufuncs {
+ I32 (*uf_val)(pTHX_ IV, SV*);
+ I32 (*uf_set)(pTHX_ IV, SV*);
+ IV uf_index;
+ };
+
+When the SV is read from or written to, the C<uf_val> or C<uf_set>
+function will be called with C<uf_index> as the first arg and a pointer to
+the SV as the second. A simple example of how to add C<PERL_MAGIC_uvar>
+magic is shown below. Note that the ufuncs structure is copied by
+sv_magic, so you can safely allocate it on the stack.
+
+ void
+ Umagic(sv)
+ SV *sv;
+ PREINIT:
+ struct ufuncs uf;
+ CODE:
+ uf.uf_val = &my_get_fn;
+ uf.uf_set = &my_set_fn;
+ uf.uf_index = 0;
+ sv_magic(sv, 0, PERL_MAGIC_uvar, (char*)&uf, sizeof(uf));
+
+Attaching C<PERL_MAGIC_uvar> to arrays is permissible but has no effect.
+
+For hashes there is a specialized hook that gives control over hash
+keys (but not values). This hook calls C<PERL_MAGIC_uvar> 'get' magic
+if the "set" function in the C<ufuncs> structure is NULL. The hook
+is activated whenever the hash is accessed with a key specified as
+an C<SV> through the functions C<hv_store_ent>, C<hv_fetch_ent>,
+C<hv_delete_ent>, and C<hv_exists_ent>. Accessing the key as a string
+through the functions without the C<..._ent> suffix circumvents the
+hook. See L<Hash::Util::Fieldhash/Guts> for a detailed description.
+
+Note that because multiple extensions may be using C<PERL_MAGIC_ext>
+or C<PERL_MAGIC_uvar> magic, it is important for extensions to take
+extra care to avoid conflict. Typically only using the magic on
+objects blessed into the same class as the extension is sufficient.
+For C<PERL_MAGIC_ext> magic, it may also be appropriate to add an I32
+'signature' at the top of the private data area and check that.
+
+Also note that the C<sv_set*()> and C<sv_cat*()> functions described
+earlier do B<not> invoke 'set' magic on their targets. This must
+be done by the user either by calling the C<SvSETMAGIC()> macro after
+calling these functions, or by using one of the C<sv_set*_mg()> or
+C<sv_cat*_mg()> functions. Similarly, generic C code must call the
+C<SvGETMAGIC()> macro to invoke any 'get' magic if they use an SV
+obtained from external sources in functions that don't handle magic.
+See L<perlapi> for a description of these functions.
+For example, calls to the C<sv_cat*()> functions typically need to be
+followed by C<SvSETMAGIC()>, but they don't need a prior C<SvGETMAGIC()>
+since their implementation handles 'get' magic.
+
+=head2 Finding Magic
+
+ MAGIC* mg_find(SV*, int type); /* Finds the magic pointer of that type */
+
+This routine returns a pointer to the C<MAGIC> structure stored in the SV.
+If the SV does not have that magical feature, C<NULL> is returned. Also,
+if the SV is not of type SVt_PVMG, Perl may core dump.
+
+ int mg_copy(SV* sv, SV* nsv, const char* key, STRLEN klen);
+
+This routine checks to see what types of magic C<sv> has. If the mg_type
+field is an uppercase letter, then the mg_obj is copied to C<nsv>, but
+the mg_type field is changed to be the lowercase letter.
+
+=head2 Understanding the Magic of Tied Hashes and Arrays
+
+Tied hashes and arrays are magical beasts of the C<PERL_MAGIC_tied>
+magic type.
+
+WARNING: As of the 5.004 release, proper usage of the array and hash
+access functions requires understanding a few caveats. Some
+of these caveats are actually considered bugs in the API, to be fixed
+in later releases, and are bracketed with [MAYCHANGE] below. If
+you find yourself actually applying such information in this section, be
+aware that the behavior may change in the future, umm, without warning.
+
+The perl tie function associates a variable with an object that implements
+the various GET, SET, etc methods. To perform the equivalent of the perl
+tie function from an XSUB, you must mimic this behaviour. The code below
+carries out the necessary steps - firstly it creates a new hash, and then
+creates a second hash which it blesses into the class which will implement
+the tie methods. Lastly it ties the two hashes together, and returns a
+reference to the new tied hash. Note that the code below does NOT call the
+TIEHASH method in the MyTie class -
+see L<Calling Perl Routines from within C Programs> for details on how
+to do this.
+
+ SV*
+ mytie()
+ PREINIT:
+ HV *hash;
+ HV *stash;
+ SV *tie;
+ CODE:
+ hash = newHV();
+ tie = newRV_noinc((SV*)newHV());
+ stash = gv_stashpv("MyTie", GV_ADD);
+ sv_bless(tie, stash);
+ hv_magic(hash, (GV*)tie, PERL_MAGIC_tied);
+ RETVAL = newRV_noinc(hash);
+ OUTPUT:
+ RETVAL
+
+The C<av_store> function, when given a tied array argument, merely
+copies the magic of the array onto the value to be "stored", using
+C<mg_copy>. It may also return NULL, indicating that the value did not
+actually need to be stored in the array. [MAYCHANGE] After a call to
+C<av_store> on a tied array, the caller will usually need to call
+C<mg_set(val)> to actually invoke the perl level "STORE" method on the
+TIEARRAY object. If C<av_store> did return NULL, a call to
+C<SvREFCNT_dec(val)> will also be usually necessary to avoid a memory
+leak. [/MAYCHANGE]
+
+The previous paragraph is applicable verbatim to tied hash access using the
+C<hv_store> and C<hv_store_ent> functions as well.
+
+C<av_fetch> and the corresponding hash functions C<hv_fetch> and
+C<hv_fetch_ent> actually return an undefined mortal value whose magic
+has been initialized using C<mg_copy>. Note the value so returned does not
+need to be deallocated, as it is already mortal. [MAYCHANGE] But you will
+need to call C<mg_get()> on the returned value in order to actually invoke
+the perl level "FETCH" method on the underlying TIE object. Similarly,
+you may also call C<mg_set()> on the return value after possibly assigning
+a suitable value to it using C<sv_setsv>, which will invoke the "STORE"
+method on the TIE object. [/MAYCHANGE]
+
+[MAYCHANGE]
+In other words, the array or hash fetch/store functions don't really
+fetch and store actual values in the case of tied arrays and hashes. They
+merely call C<mg_copy> to attach magic to the values that were meant to be
+"stored" or "fetched". Later calls to C<mg_get> and C<mg_set> actually
+do the job of invoking the TIE methods on the underlying objects. Thus
+the magic mechanism currently implements a kind of lazy access to arrays
+and hashes.
+
+Currently (as of perl version 5.004), use of the hash and array access
+functions requires the user to be aware of whether they are operating on
+"normal" hashes and arrays, or on their tied variants. The API may be
+changed to provide more transparent access to both tied and normal data
+types in future versions.
+[/MAYCHANGE]
+
+You would do well to understand that the TIEARRAY and TIEHASH interfaces
+are mere sugar to invoke some perl method calls while using the uniform hash
+and array syntax. The use of this sugar imposes some overhead (typically
+about two to four extra opcodes per FETCH/STORE operation, in addition to
+the creation of all the mortal variables required to invoke the methods).
+This overhead will be comparatively small if the TIE methods are themselves
+substantial, but if they are only a few statements long, the overhead
+will not be insignificant.
+
+=head2 Localizing changes
+
+Perl has a very handy construction
+
+ {
+ local $var = 2;
+ ...
+ }
+
+This construction is I<approximately> equivalent to
+
+ {
+ my $oldvar = $var;
+ $var = 2;
+ ...
+ $var = $oldvar;
+ }
+
+The biggest difference is that the first construction would
+reinstate the initial value of $var, irrespective of how control exits
+the block: C<goto>, C<return>, C<die>/C<eval>, etc. It is a little bit
+more efficient as well.
+
+There is a way to achieve a similar task from C via Perl API: create a
+I<pseudo-block>, and arrange for some changes to be automatically
+undone at the end of it, either explicit, or via a non-local exit (via
+die()). A I<block>-like construct is created by a pair of
+C<ENTER>/C<LEAVE> macros (see L<perlcall/"Returning a Scalar">).
+Such a construct may be created specially for some important localized
+task, or an existing one (like boundaries of enclosing Perl
+subroutine/block, or an existing pair for freeing TMPs) may be
+used. (In the second case the overhead of additional localization must
+be almost negligible.) Note that any XSUB is automatically enclosed in
+an C<ENTER>/C<LEAVE> pair.
+
+Inside such a I<pseudo-block> the following service is available:
+
+=over 4
+
+=item C<SAVEINT(int i)>
+
+=item C<SAVEIV(IV i)>
+
+=item C<SAVEI32(I32 i)>
+
+=item C<SAVELONG(long i)>
+
+These macros arrange things to restore the value of integer variable
+C<i> at the end of enclosing I<pseudo-block>.
+
+=item C<SAVESPTR(s)>
+
+=item C<SAVEPPTR(p)>
+
+These macros arrange things to restore the value of pointers C<s> and
+C<p>. C<s> must be a pointer of a type which survives conversion to
+C<SV*> and back, C<p> should be able to survive conversion to C<char*>
+and back.
+
+=item C<SAVEFREESV(SV *sv)>
+
+The refcount of C<sv> would be decremented at the end of
+I<pseudo-block>. This is similar to C<sv_2mortal> in that it is also a
+mechanism for doing a delayed C<SvREFCNT_dec>. However, while C<sv_2mortal>
+extends the lifetime of C<sv> until the beginning of the next statement,
+C<SAVEFREESV> extends it until the end of the enclosing scope. These
+lifetimes can be wildly different.
+
+Also compare C<SAVEMORTALIZESV>.
+
+=item C<SAVEMORTALIZESV(SV *sv)>
+
+Just like C<SAVEFREESV>, but mortalizes C<sv> at the end of the current
+scope instead of decrementing its reference count. This usually has the
+effect of keeping C<sv> alive until the statement that called the currently
+live scope has finished executing.
+
+=item C<SAVEFREEOP(OP *op)>
+
+The C<OP *> is op_free()ed at the end of I<pseudo-block>.
+
+=item C<SAVEFREEPV(p)>
+
+The chunk of memory which is pointed to by C<p> is Safefree()ed at the
+end of I<pseudo-block>.
+
+=item C<SAVECLEARSV(SV *sv)>
+
+Clears a slot in the current scratchpad which corresponds to C<sv> at
+the end of I<pseudo-block>.
+
+=item C<SAVEDELETE(HV *hv, char *key, I32 length)>
+
+The key C<key> of C<hv> is deleted at the end of I<pseudo-block>. The
+string pointed to by C<key> is Safefree()ed. If one has a I<key> in
+short-lived storage, the corresponding string may be reallocated like
+this:
+
+ SAVEDELETE(PL_defstash, savepv(tmpbuf), strlen(tmpbuf));
+
+=item C<SAVEDESTRUCTOR(DESTRUCTORFUNC_NOCONTEXT_t f, void *p)>
+
+At the end of I<pseudo-block> the function C<f> is called with the
+only argument C<p>.
+
+=item C<SAVEDESTRUCTOR_X(DESTRUCTORFUNC_t f, void *p)>
+
+At the end of I<pseudo-block> the function C<f> is called with the
+implicit context argument (if any), and C<p>.
+
+=item C<SAVESTACK_POS()>
+
+The current offset on the Perl internal stack (cf. C<SP>) is restored
+at the end of I<pseudo-block>.
+
+=back
+
+The following API list contains functions, thus one needs to
+provide pointers to the modifiable data explicitly (either C pointers,
+or Perlish C<GV *>s). Where the above macros take C<int>, a similar
+function takes C<int *>.
+
+=over 4
+
+=item C<SV* save_scalar(GV *gv)>
+
+Equivalent to Perl code C<local $gv>.
+
+=item C<AV* save_ary(GV *gv)>
+
+=item C<HV* save_hash(GV *gv)>
+
+Similar to C<save_scalar>, but localize C<@gv> and C<%gv>.
+
+=item C<void save_item(SV *item)>
+
+Duplicates the current value of C<SV>, on the exit from the current
+C<ENTER>/C<LEAVE> I<pseudo-block> will restore the value of C<SV>
+using the stored value. It doesn't handle magic. Use C<save_scalar> if
+magic is affected.
+
+=item C<void save_list(SV **sarg, I32 maxsarg)>
+
+A variant of C<save_item> which takes multiple arguments via an array
+C<sarg> of C<SV*> of length C<maxsarg>.
+
+=item C<SV* save_svref(SV **sptr)>
+
+Similar to C<save_scalar>, but will reinstate an C<SV *>.
+
+=item C<void save_aptr(AV **aptr)>
+
+=item C<void save_hptr(HV **hptr)>
+
+Similar to C<save_svref>, but localize C<AV *> and C<HV *>.
+
+=back
+
+The C<Alias> module implements localization of the basic types within the
+I<caller's scope>. People who are interested in how to localize things in
+the containing scope should take a look there too.
+
+=head1 Subroutines
+
+=head2 XSUBs and the Argument Stack
+
+The XSUB mechanism is a simple way for Perl programs to access C subroutines.
+An XSUB routine will have a stack that contains the arguments from the Perl
+program, and a way to map from the Perl data structures to a C equivalent.
+
+The stack arguments are accessible through the C<ST(n)> macro, which returns
+the C<n>'th stack argument. Argument 0 is the first argument passed in the
+Perl subroutine call. These arguments are C<SV*>, and can be used anywhere
+an C<SV*> is used.
+
+Most of the time, output from the C routine can be handled through use of
+the RETVAL and OUTPUT directives. However, there are some cases where the
+argument stack is not already long enough to handle all the return values.
+An example is the POSIX tzname() call, which takes no arguments, but returns
+two, the local time zone's standard and summer time abbreviations.
+
+To handle this situation, the PPCODE directive is used and the stack is
+extended using the macro:
+
+ EXTEND(SP, num);
+
+where C<SP> is the macro that represents the local copy of the stack pointer,
+and C<num> is the number of elements the stack should be extended by.
+
+Now that there is room on the stack, values can be pushed on it using C<PUSHs>
+macro. The pushed values will often need to be "mortal" (See
+L</Reference Counts and Mortality>):
+
+ PUSHs(sv_2mortal(newSViv(an_integer)))
+ PUSHs(sv_2mortal(newSVuv(an_unsigned_integer)))
+ PUSHs(sv_2mortal(newSVnv(a_double)))
+ PUSHs(sv_2mortal(newSVpv("Some String",0)))
+
+And now the Perl program calling C<tzname>, the two values will be assigned
+as in:
+
+ ($standard_abbrev, $summer_abbrev) = POSIX::tzname;
+
+An alternate (and possibly simpler) method to pushing values on the stack is
+to use the macro:
+
+ XPUSHs(SV*)
+
+This macro automatically adjust the stack for you, if needed. Thus, you
+do not need to call C<EXTEND> to extend the stack.
+
+Despite their suggestions in earlier versions of this document the macros
+C<(X)PUSH[iunp]> are I<not> suited to XSUBs which return multiple results.
+For that, either stick to the C<(X)PUSHs> macros shown above, or use the new
+C<m(X)PUSH[iunp]> macros instead; see L</Putting a C value on Perl stack>.
+
+For more information, consult L<perlxs> and L<perlxstut>.
+
+=head2 Calling Perl Routines from within C Programs
+
+There are four routines that can be used to call a Perl subroutine from
+within a C program. These four are:
+
+ I32 call_sv(SV*, I32);
+ I32 call_pv(const char*, I32);
+ I32 call_method(const char*, I32);
+ I32 call_argv(const char*, I32, register char**);
+
+The routine most often used is C<call_sv>. The C<SV*> argument
+contains either the name of the Perl subroutine to be called, or a
+reference to the subroutine. The second argument consists of flags
+that control the context in which the subroutine is called, whether
+or not the subroutine is being passed arguments, how errors should be
+trapped, and how to treat return values.
+
+All four routines return the number of arguments that the subroutine returned
+on the Perl stack.
+
+These routines used to be called C<perl_call_sv>, etc., before Perl v5.6.0,
+but those names are now deprecated; macros of the same name are provided for
+compatibility.
+
+When using any of these routines (except C<call_argv>), the programmer
+must manipulate the Perl stack. These include the following macros and
+functions:
+
+ dSP
+ SP
+ PUSHMARK()
+ PUTBACK
+ SPAGAIN
+ ENTER
+ SAVETMPS
+ FREETMPS
+ LEAVE
+ XPUSH*()
+ POP*()
+
+For a detailed description of calling conventions from C to Perl,
+consult L<perlcall>.
+
+=head2 Memory Allocation
+
+=head3 Allocation
+
+All memory meant to be used with the Perl API functions should be manipulated
+using the macros described in this section. The macros provide the necessary
+transparency between differences in the actual malloc implementation that is
+used within perl.
+
+It is suggested that you enable the version of malloc that is distributed
+with Perl. It keeps pools of various sizes of unallocated memory in
+order to satisfy allocation requests more quickly. However, on some
+platforms, it may cause spurious malloc or free errors.
+
+The following three macros are used to initially allocate memory :
+
+ Newx(pointer, number, type);
+ Newxc(pointer, number, type, cast);
+ Newxz(pointer, number, type);
+
+The first argument C<pointer> should be the name of a variable that will
+point to the newly allocated memory.
+
+The second and third arguments C<number> and C<type> specify how many of
+the specified type of data structure should be allocated. The argument
+C<type> is passed to C<sizeof>. The final argument to C<Newxc>, C<cast>,
+should be used if the C<pointer> argument is different from the C<type>
+argument.
+
+Unlike the C<Newx> and C<Newxc> macros, the C<Newxz> macro calls C<memzero>
+to zero out all the newly allocated memory.
+
+=head3 Reallocation
+
+ Renew(pointer, number, type);
+ Renewc(pointer, number, type, cast);
+ Safefree(pointer)
+
+These three macros are used to change a memory buffer size or to free a
+piece of memory no longer needed. The arguments to C<Renew> and C<Renewc>
+match those of C<New> and C<Newc> with the exception of not needing the
+"magic cookie" argument.
+
+=head3 Moving
+
+ Move(source, dest, number, type);
+ Copy(source, dest, number, type);
+ Zero(dest, number, type);
+
+These three macros are used to move, copy, or zero out previously allocated
+memory. The C<source> and C<dest> arguments point to the source and
+destination starting points. Perl will move, copy, or zero out C<number>
+instances of the size of the C<type> data structure (using the C<sizeof>
+function).
+
+=head2 PerlIO
+
+The most recent development releases of Perl has been experimenting with
+removing Perl's dependency on the "normal" standard I/O suite and allowing
+other stdio implementations to be used. This involves creating a new
+abstraction layer that then calls whichever implementation of stdio Perl
+was compiled with. All XSUBs should now use the functions in the PerlIO
+abstraction layer and not make any assumptions about what kind of stdio
+is being used.
+
+For a complete description of the PerlIO abstraction, consult L<perlapio>.
+
+=head2 Putting a C value on Perl stack
+
+A lot of opcodes (this is an elementary operation in the internal perl
+stack machine) put an SV* on the stack. However, as an optimization
+the corresponding SV is (usually) not recreated each time. The opcodes
+reuse specially assigned SVs (I<target>s) which are (as a corollary)
+not constantly freed/created.
+
+Each of the targets is created only once (but see
+L<Scratchpads and recursion> below), and when an opcode needs to put
+an integer, a double, or a string on stack, it just sets the
+corresponding parts of its I<target> and puts the I<target> on stack.
+
+The macro to put this target on stack is C<PUSHTARG>, and it is
+directly used in some opcodes, as well as indirectly in zillions of
+others, which use it via C<(X)PUSH[iunp]>.
+
+Because the target is reused, you must be careful when pushing multiple
+values on the stack. The following code will not do what you think:
+
+ XPUSHi(10);
+ XPUSHi(20);
+
+This translates as "set C<TARG> to 10, push a pointer to C<TARG> onto
+the stack; set C<TARG> to 20, push a pointer to C<TARG> onto the stack".
+At the end of the operation, the stack does not contain the values 10
+and 20, but actually contains two pointers to C<TARG>, which we have set
+to 20.
+
+If you need to push multiple different values then you should either use
+the C<(X)PUSHs> macros, or else use the new C<m(X)PUSH[iunp]> macros,
+none of which make use of C<TARG>. The C<(X)PUSHs> macros simply push an
+SV* on the stack, which, as noted under L</XSUBs and the Argument Stack>,
+will often need to be "mortal". The new C<m(X)PUSH[iunp]> macros make
+this a little easier to achieve by creating a new mortal for you (via
+C<(X)PUSHmortal>), pushing that onto the stack (extending it if necessary
+in the case of the C<mXPUSH[iunp]> macros), and then setting its value.
+Thus, instead of writing this to "fix" the example above:
+
+ XPUSHs(sv_2mortal(newSViv(10)))
+ XPUSHs(sv_2mortal(newSViv(20)))
+
+you can simply write:
+
+ mXPUSHi(10)
+ mXPUSHi(20)
+
+On a related note, if you do use C<(X)PUSH[iunp]>, then you're going to
+need a C<dTARG> in your variable declarations so that the C<*PUSH*>
+macros can make use of the local variable C<TARG>. See also C<dTARGET>
+and C<dXSTARG>.
+
+=head2 Scratchpads
+
+The question remains on when the SVs which are I<target>s for opcodes
+are created. The answer is that they are created when the current
+unit--a subroutine or a file (for opcodes for statements outside of
+subroutines)--is compiled. During this time a special anonymous Perl
+array is created, which is called a scratchpad for the current unit.
+
+A scratchpad keeps SVs which are lexicals for the current unit and are
+targets for opcodes. One can deduce that an SV lives on a scratchpad
+by looking on its flags: lexicals have C<SVs_PADMY> set, and
+I<target>s have C<SVs_PADTMP> set.
+
+The correspondence between OPs and I<target>s is not 1-to-1. Different
+OPs in the compile tree of the unit can use the same target, if this
+would not conflict with the expected life of the temporary.
+
+=head2 Scratchpads and recursion
+
+In fact it is not 100% true that a compiled unit contains a pointer to
+the scratchpad AV. In fact it contains a pointer to an AV of
+(initially) one element, and this element is the scratchpad AV. Why do
+we need an extra level of indirection?
+
+The answer is B<recursion>, and maybe B<threads>. Both
+these can create several execution pointers going into the same
+subroutine. For the subroutine-child not write over the temporaries
+for the subroutine-parent (lifespan of which covers the call to the
+child), the parent and the child should have different
+scratchpads. (I<And> the lexicals should be separate anyway!)
+
+So each subroutine is born with an array of scratchpads (of length 1).
+On each entry to the subroutine it is checked that the current
+depth of the recursion is not more than the length of this array, and
+if it is, new scratchpad is created and pushed into the array.
+
+The I<target>s on this scratchpad are C<undef>s, but they are already
+marked with correct flags.
+
+=head1 Compiled code
+
+=head2 Code tree
+
+Here we describe the internal form your code is converted to by
+Perl. Start with a simple example:
+
+ $a = $b + $c;
+
+This is converted to a tree similar to this one:
+
+ assign-to
+ / \
+ + $a
+ / \
+ $b $c
+
+(but slightly more complicated). This tree reflects the way Perl
+parsed your code, but has nothing to do with the execution order.
+There is an additional "thread" going through the nodes of the tree
+which shows the order of execution of the nodes. In our simplified
+example above it looks like:
+
+ $b ---> $c ---> + ---> $a ---> assign-to
+
+But with the actual compile tree for C<$a = $b + $c> it is different:
+some nodes I<optimized away>. As a corollary, though the actual tree
+contains more nodes than our simplified example, the execution order
+is the same as in our example.
+
+=head2 Examining the tree
+
+If you have your perl compiled for debugging (usually done with
+C<-DDEBUGGING> on the C<Configure> command line), you may examine the
+compiled tree by specifying C<-Dx> on the Perl command line. The
+output takes several lines per node, and for C<$b+$c> it looks like
+this:
+
+ 5 TYPE = add ===> 6
+ TARG = 1
+ FLAGS = (SCALAR,KIDS)
+ {
+ TYPE = null ===> (4)
+ (was rv2sv)
+ FLAGS = (SCALAR,KIDS)
+ {
+ 3 TYPE = gvsv ===> 4
+ FLAGS = (SCALAR)
+ GV = main::b
+ }
+ }
+ {
+ TYPE = null ===> (5)
+ (was rv2sv)
+ FLAGS = (SCALAR,KIDS)
+ {
+ 4 TYPE = gvsv ===> 5
+ FLAGS = (SCALAR)
+ GV = main::c
+ }
+ }
+
+This tree has 5 nodes (one per C<TYPE> specifier), only 3 of them are
+not optimized away (one per number in the left column). The immediate
+children of the given node correspond to C<{}> pairs on the same level
+of indentation, thus this listing corresponds to the tree:
+
+ add
+ / \
+ null null
+ | |
+ gvsv gvsv
+
+The execution order is indicated by C<===E<gt>> marks, thus it is C<3
+4 5 6> (node C<6> is not included into above listing), i.e.,
+C<gvsv gvsv add whatever>.
+
+Each of these nodes represents an op, a fundamental operation inside the
+Perl core. The code which implements each operation can be found in the
+F<pp*.c> files; the function which implements the op with type C<gvsv>
+is C<pp_gvsv>, and so on. As the tree above shows, different ops have
+different numbers of children: C<add> is a binary operator, as one would
+expect, and so has two children. To accommodate the various different
+numbers of children, there are various types of op data structure, and
+they link together in different ways.
+
+The simplest type of op structure is C<OP>: this has no children. Unary
+operators, C<UNOP>s, have one child, and this is pointed to by the
+C<op_first> field. Binary operators (C<BINOP>s) have not only an
+C<op_first> field but also an C<op_last> field. The most complex type of
+op is a C<LISTOP>, which has any number of children. In this case, the
+first child is pointed to by C<op_first> and the last child by
+C<op_last>. The children in between can be found by iteratively
+following the C<op_sibling> pointer from the first child to the last.
+
+There are also two other op types: a C<PMOP> holds a regular expression,
+and has no children, and a C<LOOP> may or may not have children. If the
+C<op_children> field is non-zero, it behaves like a C<LISTOP>. To
+complicate matters, if a C<UNOP> is actually a C<null> op after
+optimization (see L</Compile pass 2: context propagation>) it will still
+have children in accordance with its former type.
+
+Another way to examine the tree is to use a compiler back-end module, such
+as L<B::Concise>.
+
+=head2 Compile pass 1: check routines
+
+The tree is created by the compiler while I<yacc> code feeds it
+the constructions it recognizes. Since I<yacc> works bottom-up, so does
+the first pass of perl compilation.
+
+What makes this pass interesting for perl developers is that some
+optimization may be performed on this pass. This is optimization by
+so-called "check routines". The correspondence between node names
+and corresponding check routines is described in F<opcode.pl> (do not
+forget to run C<make regen_headers> if you modify this file).
+
+A check routine is called when the node is fully constructed except
+for the execution-order thread. Since at this time there are no
+back-links to the currently constructed node, one can do most any
+operation to the top-level node, including freeing it and/or creating
+new nodes above/below it.
+
+The check routine returns the node which should be inserted into the
+tree (if the top-level node was not modified, check routine returns
+its argument).
+
+By convention, check routines have names C<ck_*>. They are usually
+called from C<new*OP> subroutines (or C<convert>) (which in turn are
+called from F<perly.y>).
+
+=head2 Compile pass 1a: constant folding
+
+Immediately after the check routine is called the returned node is
+checked for being compile-time executable. If it is (the value is
+judged to be constant) it is immediately executed, and a I<constant>
+node with the "return value" of the corresponding subtree is
+substituted instead. The subtree is deleted.
+
+If constant folding was not performed, the execution-order thread is
+created.
+
+=head2 Compile pass 2: context propagation
+
+When a context for a part of compile tree is known, it is propagated
+down through the tree. At this time the context can have 5 values
+(instead of 2 for runtime context): void, boolean, scalar, list, and
+lvalue. In contrast with the pass 1 this pass is processed from top
+to bottom: a node's context determines the context for its children.
+
+Additional context-dependent optimizations are performed at this time.
+Since at this moment the compile tree contains back-references (via
+"thread" pointers), nodes cannot be free()d now. To allow
+optimized-away nodes at this stage, such nodes are null()ified instead
+of free()ing (i.e. their type is changed to OP_NULL).
+
+=head2 Compile pass 3: peephole optimization
+
+After the compile tree for a subroutine (or for an C<eval> or a file)
+is created, an additional pass over the code is performed. This pass
+is neither top-down or bottom-up, but in the execution order (with
+additional complications for conditionals). These optimizations are
+done in the subroutine peep(). Optimizations performed at this stage
+are subject to the same restrictions as in the pass 2.
+
+=head2 Pluggable runops
+
+The compile tree is executed in a runops function. There are two runops
+functions, in F<run.c> and in F<dump.c>. C<Perl_runops_debug> is used
+with DEBUGGING and C<Perl_runops_standard> is used otherwise. For fine
+control over the execution of the compile tree it is possible to provide
+your own runops function.
+
+It's probably best to copy one of the existing runops functions and
+change it to suit your needs. Then, in the BOOT section of your XS
+file, add the line:
+
+ PL_runops = my_runops;
+
+This function should be as efficient as possible to keep your programs
+running as fast as possible.
+
+=head1 Examining internal data structures with the C<dump> functions
+
+To aid debugging, the source file F<dump.c> contains a number of
+functions which produce formatted output of internal data structures.
+
+The most commonly used of these functions is C<Perl_sv_dump>; it's used
+for dumping SVs, AVs, HVs, and CVs. The C<Devel::Peek> module calls
+C<sv_dump> to produce debugging output from Perl-space, so users of that
+module should already be familiar with its format.
+
+C<Perl_op_dump> can be used to dump an C<OP> structure or any of its
+derivatives, and produces output similar to C<perl -Dx>; in fact,
+C<Perl_dump_eval> will dump the main root of the code being evaluated,
+exactly like C<-Dx>.
+
+Other useful functions are C<Perl_dump_sub>, which turns a C<GV> into an
+op tree, C<Perl_dump_packsubs> which calls C<Perl_dump_sub> on all the
+subroutines in a package like so: (Thankfully, these are all xsubs, so
+there is no op tree)
+
+ (gdb) print Perl_dump_packsubs(PL_defstash)
+
+ SUB attributes::bootstrap = (xsub 0x811fedc 0)
+
+ SUB UNIVERSAL::can = (xsub 0x811f50c 0)
+
+ SUB UNIVERSAL::isa = (xsub 0x811f304 0)
+
+ SUB UNIVERSAL::VERSION = (xsub 0x811f7ac 0)
+
+ SUB DynaLoader::boot_DynaLoader = (xsub 0x805b188 0)
+
+and C<Perl_dump_all>, which dumps all the subroutines in the stash and
+the op tree of the main root.
+
+=head1 How multiple interpreters and concurrency are supported
+
+=head2 Background and PERL_IMPLICIT_CONTEXT
+
+The Perl interpreter can be regarded as a closed box: it has an API
+for feeding it code or otherwise making it do things, but it also has
+functions for its own use. This smells a lot like an object, and
+there are ways for you to build Perl so that you can have multiple
+interpreters, with one interpreter represented either as a C structure,
+or inside a thread-specific structure. These structures contain all
+the context, the state of that interpreter.
+
+One macro controls the major Perl build flavor: MULTIPLICITY. The
+MULTIPLICITY build has a C structure that packages all the interpreter
+state. With multiplicity-enabled perls, PERL_IMPLICIT_CONTEXT is also
+normally defined, and enables the support for passing in a "hidden" first
+argument that represents all three data structures. MULTIPLICITY makes
+multi-threaded perls possible (with the ithreads threading model, related
+to the macro USE_ITHREADS.)
+
+Two other "encapsulation" macros are the PERL_GLOBAL_STRUCT and
+PERL_GLOBAL_STRUCT_PRIVATE (the latter turns on the former, and the
+former turns on MULTIPLICITY.) The PERL_GLOBAL_STRUCT causes all the
+internal variables of Perl to be wrapped inside a single global struct,
+struct perl_vars, accessible as (globals) &PL_Vars or PL_VarsPtr or
+the function Perl_GetVars(). The PERL_GLOBAL_STRUCT_PRIVATE goes
+one step further, there is still a single struct (allocated in main()
+either from heap or from stack) but there are no global data symbols
+pointing to it. In either case the global struct should be initialised
+as the very first thing in main() using Perl_init_global_struct() and
+correspondingly tear it down after perl_free() using Perl_free_global_struct(),
+please see F<miniperlmain.c> for usage details. You may also need
+to use C<dVAR> in your coding to "declare the global variables"
+when you are using them. dTHX does this for you automatically.
+
+To see whether you have non-const data you can use a BSD-compatible C<nm>:
+
+ nm libperl.a | grep -v ' [TURtr] '
+
+If this displays any C<D> or C<d> symbols, you have non-const data.
+
+For backward compatibility reasons defining just PERL_GLOBAL_STRUCT
+doesn't actually hide all symbols inside a big global struct: some
+PerlIO_xxx vtables are left visible. The PERL_GLOBAL_STRUCT_PRIVATE
+then hides everything (see how the PERLIO_FUNCS_DECL is used).
+
+All this obviously requires a way for the Perl internal functions to be
+either subroutines taking some kind of structure as the first
+argument, or subroutines taking nothing as the first argument. To
+enable these two very different ways of building the interpreter,
+the Perl source (as it does in so many other situations) makes heavy
+use of macros and subroutine naming conventions.
+
+First problem: deciding which functions will be public API functions and
+which will be private. All functions whose names begin C<S_> are private
+(think "S" for "secret" or "static"). All other functions begin with
+"Perl_", but just because a function begins with "Perl_" does not mean it is
+part of the API. (See L</Internal Functions>.) The easiest way to be B<sure> a
+function is part of the API is to find its entry in L<perlapi>.
+If it exists in L<perlapi>, it's part of the API. If it doesn't, and you
+think it should be (i.e., you need it for your extension), send mail via
+L<perlbug> explaining why you think it should be.
+
+Second problem: there must be a syntax so that the same subroutine
+declarations and calls can pass a structure as their first argument,
+or pass nothing. To solve this, the subroutines are named and
+declared in a particular way. Here's a typical start of a static
+function used within the Perl guts:
+
+ STATIC void
+ S_incline(pTHX_ char *s)
+
+STATIC becomes "static" in C, and may be #define'd to nothing in some
+configurations in future.
+
+A public function (i.e. part of the internal API, but not necessarily
+sanctioned for use in extensions) begins like this:
+
+ void
+ Perl_sv_setiv(pTHX_ SV* dsv, IV num)
+
+C<pTHX_> is one of a number of macros (in F<perl.h>) that hide the
+details of the interpreter's context. THX stands for "thread", "this",
+or "thingy", as the case may be. (And no, George Lucas is not involved. :-)
+The first character could be 'p' for a B<p>rototype, 'a' for B<a>rgument,
+or 'd' for B<d>eclaration, so we have C<pTHX>, C<aTHX> and C<dTHX>, and
+their variants.
+
+When Perl is built without options that set PERL_IMPLICIT_CONTEXT, there is no
+first argument containing the interpreter's context. The trailing underscore
+in the pTHX_ macro indicates that the macro expansion needs a comma
+after the context argument because other arguments follow it. If
+PERL_IMPLICIT_CONTEXT is not defined, pTHX_ will be ignored, and the
+subroutine is not prototyped to take the extra argument. The form of the
+macro without the trailing underscore is used when there are no additional
+explicit arguments.
+
+When a core function calls another, it must pass the context. This
+is normally hidden via macros. Consider C<sv_setiv>. It expands into
+something like this:
+
+ #ifdef PERL_IMPLICIT_CONTEXT
+ #define sv_setiv(a,b) Perl_sv_setiv(aTHX_ a, b)
+ /* can't do this for vararg functions, see below */
+ #else
+ #define sv_setiv Perl_sv_setiv
+ #endif
+
+This works well, and means that XS authors can gleefully write:
+
+ sv_setiv(foo, bar);
+
+and still have it work under all the modes Perl could have been
+compiled with.
+
+This doesn't work so cleanly for varargs functions, though, as macros
+imply that the number of arguments is known in advance. Instead we
+either need to spell them out fully, passing C<aTHX_> as the first
+argument (the Perl core tends to do this with functions like
+Perl_warner), or use a context-free version.
+
+The context-free version of Perl_warner is called
+Perl_warner_nocontext, and does not take the extra argument. Instead
+it does dTHX; to get the context from thread-local storage. We
+C<#define warner Perl_warner_nocontext> so that extensions get source
+compatibility at the expense of performance. (Passing an arg is
+cheaper than grabbing it from thread-local storage.)
+
+You can ignore [pad]THXx when browsing the Perl headers/sources.
+Those are strictly for use within the core. Extensions and embedders
+need only be aware of [pad]THX.
+
+=head2 So what happened to dTHR?
+
+C<dTHR> was introduced in perl 5.005 to support the older thread model.
+The older thread model now uses the C<THX> mechanism to pass context
+pointers around, so C<dTHR> is not useful any more. Perl 5.6.0 and
+later still have it for backward source compatibility, but it is defined
+to be a no-op.
+
+=head2 How do I use all this in extensions?
+
+When Perl is built with PERL_IMPLICIT_CONTEXT, extensions that call
+any functions in the Perl API will need to pass the initial context
+argument somehow. The kicker is that you will need to write it in
+such a way that the extension still compiles when Perl hasn't been
+built with PERL_IMPLICIT_CONTEXT enabled.
+
+There are three ways to do this. First, the easy but inefficient way,
+which is also the default, in order to maintain source compatibility
+with extensions: whenever F<XSUB.h> is #included, it redefines the aTHX
+and aTHX_ macros to call a function that will return the context.
+Thus, something like:
+
+ sv_setiv(sv, num);
+
+in your extension will translate to this when PERL_IMPLICIT_CONTEXT is
+in effect:
+
+ Perl_sv_setiv(Perl_get_context(), sv, num);
+
+or to this otherwise:
+
+ Perl_sv_setiv(sv, num);
+
+You have to do nothing new in your extension to get this; since
+the Perl library provides Perl_get_context(), it will all just
+work.
+
+The second, more efficient way is to use the following template for
+your Foo.xs:
+
+ #define PERL_NO_GET_CONTEXT /* we want efficiency */
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ STATIC void my_private_function(int arg1, int arg2);
+
+ STATIC void
+ my_private_function(int arg1, int arg2)
+ {
+ dTHX; /* fetch context */
+ ... call many Perl API functions ...
+ }
+
+ [... etc ...]
+
+ MODULE = Foo PACKAGE = Foo
+
+ /* typical XSUB */
+
+ void
+ my_xsub(arg)
+ int arg
+ CODE:
+ my_private_function(arg, 10);
+
+Note that the only two changes from the normal way of writing an
+extension is the addition of a C<#define PERL_NO_GET_CONTEXT> before
+including the Perl headers, followed by a C<dTHX;> declaration at
+the start of every function that will call the Perl API. (You'll
+know which functions need this, because the C compiler will complain
+that there's an undeclared identifier in those functions.) No changes
+are needed for the XSUBs themselves, because the XS() macro is
+correctly defined to pass in the implicit context if needed.
+
+The third, even more efficient way is to ape how it is done within
+the Perl guts:
+
+
+ #define PERL_NO_GET_CONTEXT /* we want efficiency */
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ /* pTHX_ only needed for functions that call Perl API */
+ STATIC void my_private_function(pTHX_ int arg1, int arg2);
+
+ STATIC void
+ my_private_function(pTHX_ int arg1, int arg2)
+ {
+ /* dTHX; not needed here, because THX is an argument */
+ ... call Perl API functions ...
+ }
+
+ [... etc ...]
+
+ MODULE = Foo PACKAGE = Foo
+
+ /* typical XSUB */
+
+ void
+ my_xsub(arg)
+ int arg
+ CODE:
+ my_private_function(aTHX_ arg, 10);
+
+This implementation never has to fetch the context using a function
+call, since it is always passed as an extra argument. Depending on
+your needs for simplicity or efficiency, you may mix the previous
+two approaches freely.
+
+Never add a comma after C<pTHX> yourself--always use the form of the
+macro with the underscore for functions that take explicit arguments,
+or the form without the argument for functions with no explicit arguments.
+
+If one is compiling Perl with the C<-DPERL_GLOBAL_STRUCT> the C<dVAR>
+definition is needed if the Perl global variables (see F<perlvars.h>
+or F<globvar.sym>) are accessed in the function and C<dTHX> is not
+used (the C<dTHX> includes the C<dVAR> if necessary). One notices
+the need for C<dVAR> only with the said compile-time define, because
+otherwise the Perl global variables are visible as-is.
+
+=head2 Should I do anything special if I call perl from multiple threads?
+
+If you create interpreters in one thread and then proceed to call them in
+another, you need to make sure perl's own Thread Local Storage (TLS) slot is
+initialized correctly in each of those threads.
+
+The C<perl_alloc> and C<perl_clone> API functions will automatically set
+the TLS slot to the interpreter they created, so that there is no need to do
+anything special if the interpreter is always accessed in the same thread that
+created it, and that thread did not create or call any other interpreters
+afterwards. If that is not the case, you have to set the TLS slot of the
+thread before calling any functions in the Perl API on that particular
+interpreter. This is done by calling the C<PERL_SET_CONTEXT> macro in that
+thread as the first thing you do:
+
+ /* do this before doing anything else with some_perl */
+ PERL_SET_CONTEXT(some_perl);
+
+ ... other Perl API calls on some_perl go here ...
+
+=head2 Future Plans and PERL_IMPLICIT_SYS
+
+Just as PERL_IMPLICIT_CONTEXT provides a way to bundle up everything
+that the interpreter knows about itself and pass it around, so too are
+there plans to allow the interpreter to bundle up everything it knows
+about the environment it's running on. This is enabled with the
+PERL_IMPLICIT_SYS macro. Currently it only works with USE_ITHREADS on
+Windows.
+
+This allows the ability to provide an extra pointer (called the "host"
+environment) for all the system calls. This makes it possible for
+all the system stuff to maintain their own state, broken down into
+seven C structures. These are thin wrappers around the usual system
+calls (see F<win32/perllib.c>) for the default perl executable, but for a
+more ambitious host (like the one that would do fork() emulation) all
+the extra work needed to pretend that different interpreters are
+actually different "processes", would be done here.
+
+The Perl engine/interpreter and the host are orthogonal entities.
+There could be one or more interpreters in a process, and one or
+more "hosts", with free association between them.
+
+=head1 Internal Functions
+
+All of Perl's internal functions which will be exposed to the outside
+world are prefixed by C<Perl_> so that they will not conflict with XS
+functions or functions used in a program in which Perl is embedded.
+Similarly, all global variables begin with C<PL_>. (By convention,
+static functions start with C<S_>.)
+
+Inside the Perl core (C<PERL_CORE> defined), you can get at the functions
+either with or without the C<Perl_> prefix, thanks to a bunch of defines
+that live in F<embed.h>. Note that extension code should I<not> set
+C<PERL_CORE>; this exposes the full perl internals, and is likely to cause
+breakage of the XS in each new perl release.
+
+The file F<embed.h> is generated automatically from
+F<embed.pl> and F<embed.fnc>. F<embed.pl> also creates the prototyping
+header files for the internal functions, generates the documentation
+and a lot of other bits and pieces. It's important that when you add
+a new function to the core or change an existing one, you change the
+data in the table in F<embed.fnc> as well. Here's a sample entry from
+that table:
+
+ Apd |SV** |av_fetch |AV* ar|I32 key|I32 lval
+
+The second column is the return type, the third column the name. Columns
+after that are the arguments. The first column is a set of flags:
+
+=over 3
+
+=item A
+
+This function is a part of the public API. All such functions should also
+have 'd', very few do not.
+
+=item p
+
+This function has a C<Perl_> prefix; i.e. it is defined as
+C<Perl_av_fetch>.
+
+=item d
+
+This function has documentation using the C<apidoc> feature which we'll
+look at in a second. Some functions have 'd' but not 'A'; docs are good.
+
+=back
+
+Other available flags are:
+
+=over 3
+
+=item s
+
+This is a static function and is defined as C<STATIC S_whatever>, and
+usually called within the sources as C<whatever(...)>.
+
+=item n
+
+This does not need a interpreter context, so the definition has no
+C<pTHX>, and it follows that callers don't use C<aTHX>. (See
+L<perlguts/Background and PERL_IMPLICIT_CONTEXT>.)
+
+=item r
+
+This function never returns; C<croak>, C<exit> and friends.
+
+=item f
+
+This function takes a variable number of arguments, C<printf> style.
+The argument list should end with C<...>, like this:
+
+ Afprd |void |croak |const char* pat|...
+
+=item M
+
+This function is part of the experimental development API, and may change
+or disappear without notice.
+
+=item o
+
+This function should not have a compatibility macro to define, say,
+C<Perl_parse> to C<parse>. It must be called as C<Perl_parse>.
+
+=item x
+
+This function isn't exported out of the Perl core.
+
+=item m
+
+This is implemented as a macro.
+
+=item X
+
+This function is explicitly exported.
+
+=item E
+
+This function is visible to extensions included in the Perl core.
+
+=item b
+
+Binary backward compatibility; this function is a macro but also has
+a C<Perl_> implementation (which is exported).
+
+=item others
+
+See the comments at the top of C<embed.fnc> for others.
+
+=back
+
+If you edit F<embed.pl> or F<embed.fnc>, you will need to run
+C<make regen_headers> to force a rebuild of F<embed.h> and other
+auto-generated files.
+
+=head2 Formatted Printing of IVs, UVs, and NVs
+
+If you are printing IVs, UVs, or NVS instead of the stdio(3) style
+formatting codes like C<%d>, C<%ld>, C<%f>, you should use the
+following macros for portability
+
+ IVdf IV in decimal
+ UVuf UV in decimal
+ UVof UV in octal
+ UVxf UV in hexadecimal
+ NVef NV %e-like
+ NVff NV %f-like
+ NVgf NV %g-like
+
+These will take care of 64-bit integers and long doubles.
+For example:
+
+ printf("IV is %"IVdf"\n", iv);
+
+The IVdf will expand to whatever is the correct format for the IVs.
+
+If you are printing addresses of pointers, use UVxf combined
+with PTR2UV(), do not use %lx or %p.
+
+=head2 Pointer-To-Integer and Integer-To-Pointer
+
+Because pointer size does not necessarily equal integer size,
+use the follow macros to do it right.
+
+ PTR2UV(pointer)
+ PTR2IV(pointer)
+ PTR2NV(pointer)
+ INT2PTR(pointertotype, integer)
+
+For example:
+
+ IV iv = ...;
+ SV *sv = INT2PTR(SV*, iv);
+
+and
+
+ AV *av = ...;
+ UV uv = PTR2UV(av);
+
+=head2 Exception Handling
+
+There are a couple of macros to do very basic exception handling in XS
+modules. You have to define C<NO_XSLOCKS> before including F<XSUB.h> to
+be able to use these macros:
+
+ #define NO_XSLOCKS
+ #include "XSUB.h"
+
+You can use these macros if you call code that may croak, but you need
+to do some cleanup before giving control back to Perl. For example:
+
+ dXCPT; /* set up necessary variables */
+
+ XCPT_TRY_START {
+ code_that_may_croak();
+ } XCPT_TRY_END
+
+ XCPT_CATCH
+ {
+ /* do cleanup here */
+ XCPT_RETHROW;
+ }
+
+Note that you always have to rethrow an exception that has been
+caught. Using these macros, it is not possible to just catch the
+exception and ignore it. If you have to ignore the exception, you
+have to use the C<call_*> function.
+
+The advantage of using the above macros is that you don't have
+to setup an extra function for C<call_*>, and that using these
+macros is faster than using C<call_*>.
+
+=head2 Source Documentation
+
+There's an effort going on to document the internal functions and
+automatically produce reference manuals from them - L<perlapi> is one
+such manual which details all the functions which are available to XS
+writers. L<perlintern> is the autogenerated manual for the functions
+which are not part of the API and are supposedly for internal use only.
+
+Source documentation is created by putting POD comments into the C
+source, like this:
+
+ /*
+ =for apidoc sv_setiv
+
+ Copies an integer into the given SV. Does not handle 'set' magic. See
+ C<sv_setiv_mg>.
+
+ =cut
+ */
+
+Please try and supply some documentation if you add functions to the
+Perl core.
+
+=head2 Backwards compatibility
+
+The Perl API changes over time. New functions are added or the interfaces
+of existing functions are changed. The C<Devel::PPPort> module tries to
+provide compatibility code for some of these changes, so XS writers don't
+have to code it themselves when supporting multiple versions of Perl.
+
+C<Devel::PPPort> generates a C header file F<ppport.h> that can also
+be run as a Perl script. To generate F<ppport.h>, run:
+
+ perl -MDevel::PPPort -eDevel::PPPort::WriteFile
+
+Besides checking existing XS code, the script can also be used to retrieve
+compatibility information for various API calls using the C<--api-info>
+command line switch. For example:
+
+ % perl ppport.h --api-info=sv_magicext
+
+For details, see C<perldoc ppport.h>.
+
+=head1 Unicode Support
+
+Perl 5.6.0 introduced Unicode support. It's important for porters and XS
+writers to understand this support and make sure that the code they
+write does not corrupt Unicode data.
+
+=head2 What B<is> Unicode, anyway?
+
+In the olden, less enlightened times, we all used to use ASCII. Most of
+us did, anyway. The big problem with ASCII is that it's American. Well,
+no, that's not actually the problem; the problem is that it's not
+particularly useful for people who don't use the Roman alphabet. What
+used to happen was that particular languages would stick their own
+alphabet in the upper range of the sequence, between 128 and 255. Of
+course, we then ended up with plenty of variants that weren't quite
+ASCII, and the whole point of it being a standard was lost.
+
+Worse still, if you've got a language like Chinese or
+Japanese that has hundreds or thousands of characters, then you really
+can't fit them into a mere 256, so they had to forget about ASCII
+altogether, and build their own systems using pairs of numbers to refer
+to one character.
+
+To fix this, some people formed Unicode, Inc. and
+produced a new character set containing all the characters you can
+possibly think of and more. There are several ways of representing these
+characters, and the one Perl uses is called UTF-8. UTF-8 uses
+a variable number of bytes to represent a character. You can learn more
+about Unicode and Perl's Unicode model in L<perlunicode>.
+
+=head2 How can I recognise a UTF-8 string?
+
+You can't. This is because UTF-8 data is stored in bytes just like
+non-UTF-8 data. The Unicode character 200, (C<0xC8> for you hex types)
+capital E with a grave accent, is represented by the two bytes
+C<v196.172>. Unfortunately, the non-Unicode string C<chr(196).chr(172)>
+has that byte sequence as well. So you can't tell just by looking - this
+is what makes Unicode input an interesting problem.
+
+In general, you either have to know what you're dealing with, or you
+have to guess. The API function C<is_utf8_string> can help; it'll tell
+you if a string contains only valid UTF-8 characters. However, it can't
+do the work for you. On a character-by-character basis, C<is_utf8_char>
+will tell you whether the current character in a string is valid UTF-8.
+
+=head2 How does UTF-8 represent Unicode characters?
+
+As mentioned above, UTF-8 uses a variable number of bytes to store a
+character. Characters with values 0...127 are stored in one byte, just
+like good ol' ASCII. Character 128 is stored as C<v194.128>; this
+continues up to character 191, which is C<v194.191>. Now we've run out of
+bits (191 is binary C<10111111>) so we move on; 192 is C<v195.128>. And
+so it goes on, moving to three bytes at character 2048.
+
+Assuming you know you're dealing with a UTF-8 string, you can find out
+how long the first character in it is with the C<UTF8SKIP> macro:
+
+ char *utf = "\305\233\340\240\201";
+ I32 len;
+
+ len = UTF8SKIP(utf); /* len is 2 here */
+ utf += len;
+ len = UTF8SKIP(utf); /* len is 3 here */
+
+Another way to skip over characters in a UTF-8 string is to use
+C<utf8_hop>, which takes a string and a number of characters to skip
+over. You're on your own about bounds checking, though, so don't use it
+lightly.
+
+All bytes in a multi-byte UTF-8 character will have the high bit set,
+so you can test if you need to do something special with this
+character like this (the UTF8_IS_INVARIANT() is a macro that tests
+whether the byte can be encoded as a single byte even in UTF-8):
+
+ U8 *utf;
+ UV uv; /* Note: a UV, not a U8, not a char */
+
+ if (!UTF8_IS_INVARIANT(*utf))
+ /* Must treat this as UTF-8 */
+ uv = utf8_to_uv(utf);
+ else
+ /* OK to treat this character as a byte */
+ uv = *utf;
+
+You can also see in that example that we use C<utf8_to_uv> to get the
+value of the character; the inverse function C<uv_to_utf8> is available
+for putting a UV into UTF-8:
+
+ if (!UTF8_IS_INVARIANT(uv))
+ /* Must treat this as UTF8 */
+ utf8 = uv_to_utf8(utf8, uv);
+ else
+ /* OK to treat this character as a byte */
+ *utf8++ = uv;
+
+You B<must> convert characters to UVs using the above functions if
+you're ever in a situation where you have to match UTF-8 and non-UTF-8
+characters. You may not skip over UTF-8 characters in this case. If you
+do this, you'll lose the ability to match hi-bit non-UTF-8 characters;
+for instance, if your UTF-8 string contains C<v196.172>, and you skip
+that character, you can never match a C<chr(200)> in a non-UTF-8 string.
+So don't do that!
+
+=head2 How does Perl store UTF-8 strings?
+
+Currently, Perl deals with Unicode strings and non-Unicode strings
+slightly differently. A flag in the SV, C<SVf_UTF8>, indicates that the
+string is internally encoded as UTF-8. Without it, the byte value is the
+codepoint number and vice versa (in other words, the string is encoded
+as iso-8859-1, but C<use feature 'unicode_strings'> is needed to get iso-8859-1
+semantics). You can check and manipulate this flag with the
+following macros:
+
+ SvUTF8(sv)
+ SvUTF8_on(sv)
+ SvUTF8_off(sv)
+
+This flag has an important effect on Perl's treatment of the string: if
+Unicode data is not properly distinguished, regular expressions,
+C<length>, C<substr> and other string handling operations will have
+undesirable results.
+
+The problem comes when you have, for instance, a string that isn't
+flagged as UTF-8, and contains a byte sequence that could be UTF-8 -
+especially when combining non-UTF-8 and UTF-8 strings.
+
+Never forget that the C<SVf_UTF8> flag is separate to the PV value; you
+need be sure you don't accidentally knock it off while you're
+manipulating SVs. More specifically, you cannot expect to do this:
+
+ SV *sv;
+ SV *nsv;
+ STRLEN len;
+ char *p;
+
+ p = SvPV(sv, len);
+ frobnicate(p);
+ nsv = newSVpvn(p, len);
+
+The C<char*> string does not tell you the whole story, and you can't
+copy or reconstruct an SV just by copying the string value. Check if the
+old SV has the UTF8 flag set, and act accordingly:
+
+ p = SvPV(sv, len);
+ frobnicate(p);
+ nsv = newSVpvn(p, len);
+ if (SvUTF8(sv))
+ SvUTF8_on(nsv);
+
+In fact, your C<frobnicate> function should be made aware of whether or
+not it's dealing with UTF-8 data, so that it can handle the string
+appropriately.
+
+Since just passing an SV to an XS function and copying the data of
+the SV is not enough to copy the UTF8 flags, even less right is just
+passing a C<char *> to an XS function.
+
+=head2 How do I convert a string to UTF-8?
+
+If you're mixing UTF-8 and non-UTF-8 strings, it is necessary to upgrade
+one of the strings to UTF-8. If you've got an SV, the easiest way to do
+this is:
+
+ sv_utf8_upgrade(sv);
+
+However, you must not do this, for example:
+
+ if (!SvUTF8(left))
+ sv_utf8_upgrade(left);
+
+If you do this in a binary operator, you will actually change one of the
+strings that came into the operator, and, while it shouldn't be noticeable
+by the end user, it can cause problems in deficient code.
+
+Instead, C<bytes_to_utf8> will give you a UTF-8-encoded B<copy> of its
+string argument. This is useful for having the data available for
+comparisons and so on, without harming the original SV. There's also
+C<utf8_to_bytes> to go the other way, but naturally, this will fail if
+the string contains any characters above 255 that can't be represented
+in a single byte.
+
+=head2 Is there anything else I need to know?
+
+Not really. Just remember these things:
+
+=over 3
+
+=item *
+
+There's no way to tell if a string is UTF-8 or not. You can tell if an SV
+is UTF-8 by looking at is C<SvUTF8> flag. Don't forget to set the flag if
+something should be UTF-8. Treat the flag as part of the PV, even though
+it's not - if you pass on the PV to somewhere, pass on the flag too.
+
+=item *
+
+If a string is UTF-8, B<always> use C<utf8_to_uv> to get at the value,
+unless C<UTF8_IS_INVARIANT(*s)> in which case you can use C<*s>.
+
+=item *
+
+When writing a character C<uv> to a UTF-8 string, B<always> use
+C<uv_to_utf8>, unless C<UTF8_IS_INVARIANT(uv))> in which case
+you can use C<*s = uv>.
+
+=item *
+
+Mixing UTF-8 and non-UTF-8 strings is tricky. Use C<bytes_to_utf8> to get
+a new string which is UTF-8 encoded, and then combine them.
+
+=back
+
+=head1 Custom Operators
+
+Custom operator support is a new experimental feature that allows you to
+define your own ops. This is primarily to allow the building of
+interpreters for other languages in the Perl core, but it also allows
+optimizations through the creation of "macro-ops" (ops which perform the
+functions of multiple ops which are usually executed together, such as
+C<gvsv, gvsv, add>.)
+
+This feature is implemented as a new op type, C<OP_CUSTOM>. The Perl
+core does not "know" anything special about this op type, and so it will
+not be involved in any optimizations. This also means that you can
+define your custom ops to be any op structure - unary, binary, list and
+so on - you like.
+
+It's important to know what custom operators won't do for you. They
+won't let you add new syntax to Perl, directly. They won't even let you
+add new keywords, directly. In fact, they won't change the way Perl
+compiles a program at all. You have to do those changes yourself, after
+Perl has compiled the program. You do this either by manipulating the op
+tree using a C<CHECK> block and the C<B::Generate> module, or by adding
+a custom peephole optimizer with the C<optimize> module.
+
+When you do this, you replace ordinary Perl ops with custom ops by
+creating ops with the type C<OP_CUSTOM> and the C<pp_addr> of your own
+PP function. This should be defined in XS code, and should look like
+the PP ops in C<pp_*.c>. You are responsible for ensuring that your op
+takes the appropriate number of values from the stack, and you are
+responsible for adding stack marks if necessary.
+
+You should also "register" your op with the Perl interpreter so that it
+can produce sensible error and warning messages. Since it is possible to
+have multiple custom ops within the one "logical" op type C<OP_CUSTOM>,
+Perl uses the value of C<< o->op_ppaddr >> as a key into the
+C<PL_custom_op_descs> and C<PL_custom_op_names> hashes. This means you
+need to enter a name and description for your op at the appropriate
+place in the C<PL_custom_op_names> and C<PL_custom_op_descs> hashes.
+
+C<B::Generate> directly supports the creation of custom ops by name.
+
+=head1 AUTHORS
+
+Until May 1997, this document was maintained by Jeff Okamoto
+E<lt>okamoto@corp.hp.comE<gt>. It is now maintained as part of Perl
+itself by the Perl 5 Porters E<lt>perl5-porters@perl.orgE<gt>.
+
+With lots of help and suggestions from Dean Roehrich, Malcolm Beattie,
+Andreas Koenig, Paul Hudson, Ilya Zakharevich, Paul Marquess, Neil
+Bowers, Matthew Green, Tim Bunce, Spider Boardman, Ulrich Pfeifer,
+Stephen McCamant, and Gurusamy Sarathy.
+
+=head1 SEE ALSO
+
+L<perlapi>, L<perlintern>, L<perlxs>, L<perlembed>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlhack.pod b/Master/tlpkg/tlperl/lib/pods/perlhack.pod
new file mode 100644
index 00000000000..844b83b7b05
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlhack.pod
@@ -0,0 +1,3401 @@
+=head1 NAME
+
+perlhack - How to hack at the Perl internals
+
+=head1 DESCRIPTION
+
+This document attempts to explain how Perl development takes place,
+and ends with some suggestions for people wanting to become bona fide
+porters.
+
+The perl5-porters mailing list is where the Perl standard distribution
+is maintained and developed. The list can get anywhere from 10 to 150
+messages a day, depending on the heatedness of the debate. Most days
+there are two or three patches, extensions, features, or bugs being
+discussed at a time.
+
+A searchable archive of the list is at either:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
+
+or
+
+ http://archive.develooper.com/perl5-porters@perl.org/
+
+List subscribers (the porters themselves) come in several flavours.
+Some are quiet curious lurkers, who rarely pitch in and instead watch
+the ongoing development to ensure they're forewarned of new changes or
+features in Perl. Some are representatives of vendors, who are there
+to make sure that Perl continues to compile and work on their
+platforms. Some patch any reported bug that they know how to fix,
+some are actively patching their pet area (threads, Win32, the regexp
+engine), while others seem to do nothing but complain. In other
+words, it's your usual mix of technical people.
+
+Over this group of porters presides Larry Wall. He has the final word
+in what does and does not change in the Perl language. Various
+releases of Perl are shepherded by a "pumpking", a porter
+responsible for gathering patches, deciding on a patch-by-patch,
+feature-by-feature basis what will and will not go into the release.
+For instance, Gurusamy Sarathy was the pumpking for the 5.6 release of
+Perl, and Jarkko Hietaniemi was the pumpking for the 5.8 release, and
+Rafael Garcia-Suarez holds the pumpking crown for the 5.10 release.
+
+In addition, various people are pumpkings for different things. For
+instance, Andy Dougherty and Jarkko Hietaniemi did a grand job as the
+I<Configure> pumpkin up till the 5.8 release. For the 5.10 release
+H.Merijn Brand took over.
+
+Larry sees Perl development along the lines of the US government:
+there's the Legislature (the porters), the Executive branch (the
+pumpkings), and the Supreme Court (Larry). The legislature can
+discuss and submit patches to the executive branch all they like, but
+the executive branch is free to veto them. Rarely, the Supreme Court
+will side with the executive branch over the legislature, or the
+legislature over the executive branch. Mostly, however, the
+legislature and the executive branch are supposed to get along and
+work out their differences without impeachment or court cases.
+
+You might sometimes see reference to Rule 1 and Rule 2. Larry's power
+as Supreme Court is expressed in The Rules:
+
+=over 4
+
+=item 1
+
+Larry is always by definition right about how Perl should behave.
+This means he has final veto power on the core functionality.
+
+=item 2
+
+Larry is allowed to change his mind about any matter at a later date,
+regardless of whether he previously invoked Rule 1.
+
+=back
+
+Got that? Larry is always right, even when he was wrong. It's rare
+to see either Rule exercised, but they are often alluded to.
+
+New features and extensions to the language are contentious, because
+the criteria used by the pumpkings, Larry, and other porters to decide
+which features should be implemented and incorporated are not codified
+in a few small design goals as with some other languages. Instead,
+the heuristics are flexible and often difficult to fathom. Here is
+one person's list, roughly in decreasing order of importance, of
+heuristics that new features have to be weighed against:
+
+=over 4
+
+=item Does concept match the general goals of Perl?
+
+These haven't been written anywhere in stone, but one approximation
+is:
+
+ 1. Keep it fast, simple, and useful.
+ 2. Keep features/concepts as orthogonal as possible.
+ 3. No arbitrary limits (platforms, data sizes, cultures).
+ 4. Keep it open and exciting to use/patch/advocate Perl everywhere.
+ 5. Either assimilate new technologies, or build bridges to them.
+
+=item Where is the implementation?
+
+All the talk in the world is useless without an implementation. In
+almost every case, the person or people who argue for a new feature
+will be expected to be the ones who implement it. Porters capable
+of coding new features have their own agendas, and are not available
+to implement your (possibly good) idea.
+
+=item Backwards compatibility
+
+It's a cardinal sin to break existing Perl programs. New warnings are
+contentious--some say that a program that emits warnings is not
+broken, while others say it is. Adding keywords has the potential to
+break programs, changing the meaning of existing token sequences or
+functions might break programs.
+
+=item Could it be a module instead?
+
+Perl 5 has extension mechanisms, modules and XS, specifically to avoid
+the need to keep changing the Perl interpreter. You can write modules
+that export functions, you can give those functions prototypes so they
+can be called like built-in functions, you can even write XS code to
+mess with the runtime data structures of the Perl interpreter if you
+want to implement really complicated things. If it can be done in a
+module instead of in the core, it's highly unlikely to be added.
+
+=item Is the feature generic enough?
+
+Is this something that only the submitter wants added to the language,
+or would it be broadly useful? Sometimes, instead of adding a feature
+with a tight focus, the porters might decide to wait until someone
+implements the more generalized feature. For instance, instead of
+implementing a "delayed evaluation" feature, the porters are waiting
+for a macro system that would permit delayed evaluation and much more.
+
+=item Does it potentially introduce new bugs?
+
+Radical rewrites of large chunks of the Perl interpreter have the
+potential to introduce new bugs. The smaller and more localized the
+change, the better.
+
+=item Does it preclude other desirable features?
+
+A patch is likely to be rejected if it closes off future avenues of
+development. For instance, a patch that placed a true and final
+interpretation on prototypes is likely to be rejected because there
+are still options for the future of prototypes that haven't been
+addressed.
+
+=item Is the implementation robust?
+
+Good patches (tight code, complete, correct) stand more chance of
+going in. Sloppy or incorrect patches might be placed on the back
+burner until the pumpking has time to fix, or might be discarded
+altogether without further notice.
+
+=item Is the implementation generic enough to be portable?
+
+The worst patches make use of a system-specific features. It's highly
+unlikely that non-portable additions to the Perl language will be
+accepted.
+
+=item Is the implementation tested?
+
+Patches which change behaviour (fixing bugs or introducing new features)
+must include regression tests to verify that everything works as expected.
+Without tests provided by the original author, how can anyone else changing
+perl in the future be sure that they haven't unwittingly broken the behaviour
+the patch implements? And without tests, how can the patch's author be
+confident that his/her hard work put into the patch won't be accidentally
+thrown away by someone in the future?
+
+=item Is there enough documentation?
+
+Patches without documentation are probably ill-thought out or
+incomplete. Nothing can be added without documentation, so submitting
+a patch for the appropriate manpages as well as the source code is
+always a good idea.
+
+=item Is there another way to do it?
+
+Larry said "Although the Perl Slogan is I<There's More Than One Way
+to Do It>, I hesitate to make 10 ways to do something". This is a
+tricky heuristic to navigate, though--one man's essential addition is
+another man's pointless cruft.
+
+=item Does it create too much work?
+
+Work for the pumpking, work for Perl programmers, work for module
+authors, ... Perl is supposed to be easy.
+
+=item Patches speak louder than words
+
+Working code is always preferred to pie-in-the-sky ideas. A patch to
+add a feature stands a much higher chance of making it to the language
+than does a random feature request, no matter how fervently argued the
+request might be. This ties into "Will it be useful?", as the fact
+that someone took the time to make the patch demonstrates a strong
+desire for the feature.
+
+=back
+
+If you're on the list, you might hear the word "core" bandied
+around. It refers to the standard distribution. "Hacking on the
+core" means you're changing the C source code to the Perl
+interpreter. "A core module" is one that ships with Perl.
+
+=head2 Keeping in sync
+
+The source code to the Perl interpreter, in its different versions, is
+kept in a repository managed by the git revision control system. The
+pumpkings and a few others have write access to the repository to check in
+changes.
+
+How to clone and use the git perl repository is described in L<perlrepository>.
+
+You can also choose to use rsync to get a copy of the current source tree
+for the bleadperl branch and all maintenance branches:
+
+ $ rsync -avz rsync://perl5.git.perl.org/perl-current .
+ $ rsync -avz rsync://perl5.git.perl.org/perl-5.12.x .
+ $ rsync -avz rsync://perl5.git.perl.org/perl-5.10.x .
+ $ rsync -avz rsync://perl5.git.perl.org/perl-5.8.x .
+ $ rsync -avz rsync://perl5.git.perl.org/perl-5.6.x .
+ $ rsync -avz rsync://perl5.git.perl.org/perl-5.005xx .
+
+(Add the C<--delete> option to remove leftover files)
+
+To get a full list of the available sync points:
+
+ $ rsync perl5.git.perl.org::
+
+You may also want to subscribe to the perl5-changes mailing list to
+receive a copy of each patch that gets submitted to the maintenance
+and development "branches" of the perl repository. See
+http://lists.perl.org/ for subscription information.
+
+If you are a member of the perl5-porters mailing list, it is a good
+thing to keep in touch with the most recent changes. If not only to
+verify if what you would have posted as a bug report isn't already
+solved in the most recent available perl development branch, also
+known as perl-current, bleading edge perl, bleedperl or bleadperl.
+
+Needless to say, the source code in perl-current is usually in a perpetual
+state of evolution. You should expect it to be very buggy. Do B<not> use
+it for any purpose other than testing and development.
+
+=head2 Perlbug administration
+
+There is a single remote administrative interface for modifying bug status,
+category, open issues etc. using the B<RT> bugtracker system, maintained
+by Robert Spier. Become an administrator, and close any bugs you can get
+your sticky mitts on:
+
+ http://bugs.perl.org/
+
+To email the bug system administrators:
+
+ "perlbug-admin" <perlbug-admin@perl.org>
+
+=head2 Submitting patches
+
+Always submit patches to I<perl5-porters@perl.org>. If you're
+patching a core module and there's an author listed, send the author a
+copy (see L<Patching a core module>). This lets other porters review
+your patch, which catches a surprising number of errors in patches.
+Please patch against the latest B<development> version. (e.g., even if
+you're fixing a bug in the 5.8 track, patch against the C<blead> branch in
+the git repository.)
+
+If changes are accepted, they are applied to the development branch. Then
+the maintenance pumpking decides which of those patches is to be
+backported to the maint branch. Only patches that survive the heat of the
+development branch get applied to maintenance versions.
+
+Your patch should update the documentation and test suite. See
+L<Writing a test>. If you have added or removed files in the distribution,
+edit the MANIFEST file accordingly, sort the MANIFEST file using
+C<make manisort>, and include those changes as part of your patch.
+
+Patching documentation also follows the same order: if accepted, a patch
+is first applied to B<development>, and if relevant then it's backported
+to B<maintenance>. (With an exception for some patches that document
+behaviour that only appears in the maintenance branch, but which has
+changed in the development version.)
+
+To report a bug in Perl, use the program I<perlbug> which comes with
+Perl (if you can't get Perl to work, send mail to the address
+I<perlbug@perl.org> or I<perlbug@perl.com>). Reporting bugs through
+I<perlbug> feeds into the automated bug-tracking system, access to
+which is provided through the web at http://rt.perl.org/rt3/ . It
+often pays to check the archives of the perl5-porters mailing list to
+see whether the bug you're reporting has been reported before, and if
+so whether it was considered a bug. See above for the location of
+the searchable archives.
+
+The CPAN testers ( http://testers.cpan.org/ ) are a group of
+volunteers who test CPAN modules on a variety of platforms. Perl
+Smokers ( http://www.nntp.perl.org/group/perl.daily-build and
+http://www.nntp.perl.org/group/perl.daily-build.reports/ )
+automatically test Perl source releases on platforms with various
+configurations. Both efforts welcome volunteers. In order to get
+involved in smoke testing of the perl itself visit
+L<http://search.cpan.org/dist/Test-Smoke>. In order to start smoke
+testing CPAN modules visit L<http://search.cpan.org/dist/CPANPLUS-YACSmoke/>
+or L<http://search.cpan.org/dist/minismokebox/> or
+L<http://search.cpan.org/dist/CPAN-Reporter/>.
+
+It's a good idea to read and lurk for a while before chipping in.
+That way you'll get to see the dynamic of the conversations, learn the
+personalities of the players, and hopefully be better prepared to make
+a useful contribution when do you speak up.
+
+If after all this you still think you want to join the perl5-porters
+mailing list, send mail to I<perl5-porters-subscribe@perl.org>. To
+unsubscribe, send mail to I<perl5-porters-unsubscribe@perl.org>.
+
+To hack on the Perl guts, you'll need to read the following things:
+
+=over 3
+
+=item L<perlguts>
+
+This is of paramount importance, since it's the documentation of what
+goes where in the Perl source. Read it over a couple of times and it
+might start to make sense - don't worry if it doesn't yet, because the
+best way to study it is to read it in conjunction with poking at Perl
+source, and we'll do that later on.
+
+Gisle Aas's "illustrated perlguts", also known as I<illguts>, has very
+helpful pictures:
+
+L<http://search.cpan.org/dist/illguts/>
+
+=item L<perlxstut> and L<perlxs>
+
+A working knowledge of XSUB programming is incredibly useful for core
+hacking; XSUBs use techniques drawn from the PP code, the portion of the
+guts that actually executes a Perl program. It's a lot gentler to learn
+those techniques from simple examples and explanation than from the core
+itself.
+
+=item L<perlapi>
+
+The documentation for the Perl API explains what some of the internal
+functions do, as well as the many macros used in the source.
+
+=item F<Porting/pumpkin.pod>
+
+This is a collection of words of wisdom for a Perl porter; some of it is
+only useful to the pumpkin holder, but most of it applies to anyone
+wanting to go about Perl development.
+
+=item The perl5-porters FAQ
+
+This should be available from http://dev.perl.org/perl5/docs/p5p-faq.html .
+It contains hints on reading perl5-porters, information on how
+perl5-porters works and how Perl development in general works.
+
+=back
+
+=head2 Finding Your Way Around
+
+Perl maintenance can be split into a number of areas, and certain people
+(pumpkins) will have responsibility for each area. These areas sometimes
+correspond to files or directories in the source kit. Among the areas are:
+
+=over 3
+
+=item Core modules
+
+Modules shipped as part of the Perl core live in various subdirectories, where
+two are dedicated to core-only modules, and two are for the dual-life modules
+which live on CPAN and may be maintained separately with respect to the Perl
+core:
+
+ lib/ is for pure-Perl modules, which exist in the core only.
+
+ ext/ is for XS extensions, and modules with special Makefile.PL
+ requirements, which exist in the core only.
+
+ cpan/ is for dual-life modules, where the CPAN module is
+ canonical (should be patched first).
+
+ dist/ is for dual-life modules, where the blead source is
+ canonical.
+
+For some dual-life modules it has not been discussed if the CPAN version or the
+blead source is canonical. Until that is done, those modules should be in
+F<cpan/>.
+
+=item Tests
+
+There are tests for nearly all the modules, built-ins and major bits
+of functionality. Test files all have a .t suffix. Module tests live
+in the F<lib/> and F<ext/> directories next to the module being
+tested. Others live in F<t/>. See L<Writing a test>
+
+=item Documentation
+
+Documentation maintenance includes looking after everything in the
+F<pod/> directory, (as well as contributing new documentation) and
+the documentation to the modules in core.
+
+=item Configure
+
+The Configure process is the way we make Perl portable across the
+myriad of operating systems it supports. Responsibility for the
+Configure, build and installation process, as well as the overall
+portability of the core code rests with the Configure pumpkin -
+others help out with individual operating systems.
+
+The three files that fall under his/her responsibility are Configure,
+config_h.SH, and Porting/Glossary (and a whole bunch of small related
+files that are less important here). The Configure pumpkin decides how
+patches to these are dealt with. Currently, the Configure pumpkin will
+accept patches in most common formats, even directly to these files.
+Other committers are allowed to commit to these files under the strict
+condition that they will inform the Configure pumpkin, either on IRC
+(if he/she happens to be around) or through (personal) e-mail.
+
+The files involved are the operating system directories, (F<win32/>,
+F<os2/>, F<vms/> and so on) the shell scripts which generate F<config.h>
+and F<Makefile>, as well as the metaconfig files which generate
+F<Configure>. (metaconfig isn't included in the core distribution.)
+
+See http://perl5.git.perl.org/metaconfig.git/blob/HEAD:/README for a
+description of the full process involved.
+
+=item Interpreter
+
+And of course, there's the core of the Perl interpreter itself. Let's
+have a look at that in a little more detail.
+
+=back
+
+Before we leave looking at the layout, though, don't forget that
+F<MANIFEST> contains not only the file names in the Perl distribution,
+but short descriptions of what's in them, too. For an overview of the
+important files, try this:
+
+ perl -lne 'print if /^[^\/]+\.[ch]\s+/' MANIFEST
+
+=head2 Elements of the interpreter
+
+The work of the interpreter has two main stages: compiling the code
+into the internal representation, or bytecode, and then executing it.
+L<perlguts/Compiled code> explains exactly how the compilation stage
+happens.
+
+Here is a short breakdown of perl's operation:
+
+=over 3
+
+=item Startup
+
+The action begins in F<perlmain.c>. (or F<miniperlmain.c> for miniperl)
+This is very high-level code, enough to fit on a single screen, and it
+resembles the code found in L<perlembed>; most of the real action takes
+place in F<perl.c>
+
+F<perlmain.c> is generated by L<writemain> from F<miniperlmain.c> at
+make time, so you should make perl to follow this along.
+
+First, F<perlmain.c> allocates some memory and constructs a Perl
+interpreter, along these lines:
+
+ 1 PERL_SYS_INIT3(&argc,&argv,&env);
+ 2
+ 3 if (!PL_do_undump) {
+ 4 my_perl = perl_alloc();
+ 5 if (!my_perl)
+ 6 exit(1);
+ 7 perl_construct(my_perl);
+ 8 PL_perl_destruct_level = 0;
+ 9 }
+
+Line 1 is a macro, and its definition is dependent on your operating
+system. Line 3 references C<PL_do_undump>, a global variable - all
+global variables in Perl start with C<PL_>. This tells you whether the
+current running program was created with the C<-u> flag to perl and then
+F<undump>, which means it's going to be false in any sane context.
+
+Line 4 calls a function in F<perl.c> to allocate memory for a Perl
+interpreter. It's quite a simple function, and the guts of it looks like
+this:
+
+ my_perl = (PerlInterpreter*)PerlMem_malloc(sizeof(PerlInterpreter));
+
+Here you see an example of Perl's system abstraction, which we'll see
+later: C<PerlMem_malloc> is either your system's C<malloc>, or Perl's
+own C<malloc> as defined in F<malloc.c> if you selected that option at
+configure time.
+
+Next, in line 7, we construct the interpreter using perl_construct,
+also in F<perl.c>; this sets up all the special variables that Perl
+needs, the stacks, and so on.
+
+Now we pass Perl the command line options, and tell it to go:
+
+ exitstatus = perl_parse(my_perl, xs_init, argc, argv, (char **)NULL);
+ if (!exitstatus)
+ perl_run(my_perl);
+
+ exitstatus = perl_destruct(my_perl);
+
+ perl_free(my_perl);
+
+C<perl_parse> is actually a wrapper around C<S_parse_body>, as defined
+in F<perl.c>, which processes the command line options, sets up any
+statically linked XS modules, opens the program and calls C<yyparse> to
+parse it.
+
+=item Parsing
+
+The aim of this stage is to take the Perl source, and turn it into an op
+tree. We'll see what one of those looks like later. Strictly speaking,
+there's three things going on here.
+
+C<yyparse>, the parser, lives in F<perly.c>, although you're better off
+reading the original YACC input in F<perly.y>. (Yes, Virginia, there
+B<is> a YACC grammar for Perl!) The job of the parser is to take your
+code and "understand" it, splitting it into sentences, deciding which
+operands go with which operators and so on.
+
+The parser is nobly assisted by the lexer, which chunks up your input
+into tokens, and decides what type of thing each token is: a variable
+name, an operator, a bareword, a subroutine, a core function, and so on.
+The main point of entry to the lexer is C<yylex>, and that and its
+associated routines can be found in F<toke.c>. Perl isn't much like
+other computer languages; it's highly context sensitive at times, it can
+be tricky to work out what sort of token something is, or where a token
+ends. As such, there's a lot of interplay between the tokeniser and the
+parser, which can get pretty frightening if you're not used to it.
+
+As the parser understands a Perl program, it builds up a tree of
+operations for the interpreter to perform during execution. The routines
+which construct and link together the various operations are to be found
+in F<op.c>, and will be examined later.
+
+=item Optimization
+
+Now the parsing stage is complete, and the finished tree represents
+the operations that the Perl interpreter needs to perform to execute our
+program. Next, Perl does a dry run over the tree looking for
+optimisations: constant expressions such as C<3 + 4> will be computed
+now, and the optimizer will also see if any multiple operations can be
+replaced with a single one. For instance, to fetch the variable C<$foo>,
+instead of grabbing the glob C<*foo> and looking at the scalar
+component, the optimizer fiddles the op tree to use a function which
+directly looks up the scalar in question. The main optimizer is C<peep>
+in F<op.c>, and many ops have their own optimizing functions.
+
+=item Running
+
+Now we're finally ready to go: we have compiled Perl byte code, and all
+that's left to do is run it. The actual execution is done by the
+C<runops_standard> function in F<run.c>; more specifically, it's done by
+these three innocent looking lines:
+
+ while ((PL_op = CALL_FPTR(PL_op->op_ppaddr)(aTHX))) {
+ PERL_ASYNC_CHECK();
+ }
+
+You may be more comfortable with the Perl version of that:
+
+ PERL_ASYNC_CHECK() while $Perl::op = &{$Perl::op->{function}};
+
+Well, maybe not. Anyway, each op contains a function pointer, which
+stipulates the function which will actually carry out the operation.
+This function will return the next op in the sequence - this allows for
+things like C<if> which choose the next op dynamically at run time.
+The C<PERL_ASYNC_CHECK> makes sure that things like signals interrupt
+execution if required.
+
+The actual functions called are known as PP code, and they're spread
+between four files: F<pp_hot.c> contains the "hot" code, which is most
+often used and highly optimized, F<pp_sys.c> contains all the
+system-specific functions, F<pp_ctl.c> contains the functions which
+implement control structures (C<if>, C<while> and the like) and F<pp.c>
+contains everything else. These are, if you like, the C code for Perl's
+built-in functions and operators.
+
+Note that each C<pp_> function is expected to return a pointer to the next
+op. Calls to perl subs (and eval blocks) are handled within the same
+runops loop, and do not consume extra space on the C stack. For example,
+C<pp_entersub> and C<pp_entertry> just push a C<CxSUB> or C<CxEVAL> block
+struct onto the context stack which contain the address of the op
+following the sub call or eval. They then return the first op of that sub
+or eval block, and so execution continues of that sub or block. Later, a
+C<pp_leavesub> or C<pp_leavetry> op pops the C<CxSUB> or C<CxEVAL>,
+retrieves the return op from it, and returns it.
+
+=item Exception handing
+
+Perl's exception handing (i.e. C<die> etc.) is built on top of the low-level
+C<setjmp()>/C<longjmp()> C-library functions. These basically provide a
+way to capture the current PC and SP registers and later restore them; i.e.
+a C<longjmp()> continues at the point in code where a previous C<setjmp()>
+was done, with anything further up on the C stack being lost. This is why
+code should always save values using C<SAVE_FOO> rather than in auto
+variables.
+
+The perl core wraps C<setjmp()> etc in the macros C<JMPENV_PUSH> and
+C<JMPENV_JUMP>. The basic rule of perl exceptions is that C<exit>, and
+C<die> (in the absence of C<eval>) perform a C<JMPENV_JUMP(2)>, while
+C<die> within C<eval> does a C<JMPENV_JUMP(3)>.
+
+At entry points to perl, such as C<perl_parse()>, C<perl_run()> and
+C<call_sv(cv, G_EVAL)> each does a C<JMPENV_PUSH>, then enter a runops
+loop or whatever, and handle possible exception returns. For a 2 return,
+final cleanup is performed, such as popping stacks and calling C<CHECK> or
+C<END> blocks. Amongst other things, this is how scope cleanup still
+occurs during an C<exit>.
+
+If a C<die> can find a C<CxEVAL> block on the context stack, then the
+stack is popped to that level and the return op in that block is assigned
+to C<PL_restartop>; then a C<JMPENV_JUMP(3)> is performed. This normally
+passes control back to the guard. In the case of C<perl_run> and
+C<call_sv>, a non-null C<PL_restartop> triggers re-entry to the runops
+loop. The is the normal way that C<die> or C<croak> is handled within an
+C<eval>.
+
+Sometimes ops are executed within an inner runops loop, such as tie, sort
+or overload code. In this case, something like
+
+ sub FETCH { eval { die } }
+
+would cause a longjmp right back to the guard in C<perl_run>, popping both
+runops loops, which is clearly incorrect. One way to avoid this is for the
+tie code to do a C<JMPENV_PUSH> before executing C<FETCH> in the inner
+runops loop, but for efficiency reasons, perl in fact just sets a flag,
+using C<CATCH_SET(TRUE)>. The C<pp_require>, C<pp_entereval> and
+C<pp_entertry> ops check this flag, and if true, they call C<docatch>,
+which does a C<JMPENV_PUSH> and starts a new runops level to execute the
+code, rather than doing it on the current loop.
+
+As a further optimisation, on exit from the eval block in the C<FETCH>,
+execution of the code following the block is still carried on in the inner
+loop. When an exception is raised, C<docatch> compares the C<JMPENV>
+level of the C<CxEVAL> with C<PL_top_env> and if they differ, just
+re-throws the exception. In this way any inner loops get popped.
+
+Here's an example.
+
+ 1: eval { tie @a, 'A' };
+ 2: sub A::TIEARRAY {
+ 3: eval { die };
+ 4: die;
+ 5: }
+
+To run this code, C<perl_run> is called, which does a C<JMPENV_PUSH> then
+enters a runops loop. This loop executes the eval and tie ops on line 1,
+with the eval pushing a C<CxEVAL> onto the context stack.
+
+The C<pp_tie> does a C<CATCH_SET(TRUE)>, then starts a second runops loop
+to execute the body of C<TIEARRAY>. When it executes the entertry op on
+line 3, C<CATCH_GET> is true, so C<pp_entertry> calls C<docatch> which
+does a C<JMPENV_PUSH> and starts a third runops loop, which then executes
+the die op. At this point the C call stack looks like this:
+
+ Perl_pp_die
+ Perl_runops # third loop
+ S_docatch_body
+ S_docatch
+ Perl_pp_entertry
+ Perl_runops # second loop
+ S_call_body
+ Perl_call_sv
+ Perl_pp_tie
+ Perl_runops # first loop
+ S_run_body
+ perl_run
+ main
+
+and the context and data stacks, as shown by C<-Dstv>, look like:
+
+ STACK 0: MAIN
+ CX 0: BLOCK =>
+ CX 1: EVAL => AV() PV("A"\0)
+ retop=leave
+ STACK 1: MAGIC
+ CX 0: SUB =>
+ retop=(null)
+ CX 1: EVAL => *
+ retop=nextstate
+
+The die pops the first C<CxEVAL> off the context stack, sets
+C<PL_restartop> from it, does a C<JMPENV_JUMP(3)>, and control returns to
+the top C<docatch>. This then starts another third-level runops level,
+which executes the nextstate, pushmark and die ops on line 4. At the point
+that the second C<pp_die> is called, the C call stack looks exactly like
+that above, even though we are no longer within an inner eval; this is
+because of the optimization mentioned earlier. However, the context stack
+now looks like this, ie with the top CxEVAL popped:
+
+ STACK 0: MAIN
+ CX 0: BLOCK =>
+ CX 1: EVAL => AV() PV("A"\0)
+ retop=leave
+ STACK 1: MAGIC
+ CX 0: SUB =>
+ retop=(null)
+
+The die on line 4 pops the context stack back down to the CxEVAL, leaving
+it as:
+
+ STACK 0: MAIN
+ CX 0: BLOCK =>
+
+As usual, C<PL_restartop> is extracted from the C<CxEVAL>, and a
+C<JMPENV_JUMP(3)> done, which pops the C stack back to the docatch:
+
+ S_docatch
+ Perl_pp_entertry
+ Perl_runops # second loop
+ S_call_body
+ Perl_call_sv
+ Perl_pp_tie
+ Perl_runops # first loop
+ S_run_body
+ perl_run
+ main
+
+In this case, because the C<JMPENV> level recorded in the C<CxEVAL>
+differs from the current one, C<docatch> just does a C<JMPENV_JUMP(3)>
+and the C stack unwinds to:
+
+ perl_run
+ main
+
+Because C<PL_restartop> is non-null, C<run_body> starts a new runops loop
+and execution continues.
+
+=back
+
+=head2 Internal Variable Types
+
+You should by now have had a look at L<perlguts>, which tells you about
+Perl's internal variable types: SVs, HVs, AVs and the rest. If not, do
+that now.
+
+These variables are used not only to represent Perl-space variables, but
+also any constants in the code, as well as some structures completely
+internal to Perl. The symbol table, for instance, is an ordinary Perl
+hash. Your code is represented by an SV as it's read into the parser;
+any program files you call are opened via ordinary Perl filehandles, and
+so on.
+
+The core L<Devel::Peek|Devel::Peek> module lets us examine SVs from a
+Perl program. Let's see, for instance, how Perl treats the constant
+C<"hello">.
+
+ % perl -MDevel::Peek -e 'Dump("hello")'
+ 1 SV = PV(0xa041450) at 0xa04ecbc
+ 2 REFCNT = 1
+ 3 FLAGS = (POK,READONLY,pPOK)
+ 4 PV = 0xa0484e0 "hello"\0
+ 5 CUR = 5
+ 6 LEN = 6
+
+Reading C<Devel::Peek> output takes a bit of practise, so let's go
+through it line by line.
+
+Line 1 tells us we're looking at an SV which lives at C<0xa04ecbc> in
+memory. SVs themselves are very simple structures, but they contain a
+pointer to a more complex structure. In this case, it's a PV, a
+structure which holds a string value, at location C<0xa041450>. Line 2
+is the reference count; there are no other references to this data, so
+it's 1.
+
+Line 3 are the flags for this SV - it's OK to use it as a PV, it's a
+read-only SV (because it's a constant) and the data is a PV internally.
+Next we've got the contents of the string, starting at location
+C<0xa0484e0>.
+
+Line 5 gives us the current length of the string - note that this does
+B<not> include the null terminator. Line 6 is not the length of the
+string, but the length of the currently allocated buffer; as the string
+grows, Perl automatically extends the available storage via a routine
+called C<SvGROW>.
+
+You can get at any of these quantities from C very easily; just add
+C<Sv> to the name of the field shown in the snippet, and you've got a
+macro which will return the value: C<SvCUR(sv)> returns the current
+length of the string, C<SvREFCOUNT(sv)> returns the reference count,
+C<SvPV(sv, len)> returns the string itself with its length, and so on.
+More macros to manipulate these properties can be found in L<perlguts>.
+
+Let's take an example of manipulating a PV, from C<sv_catpvn>, in F<sv.c>
+
+ 1 void
+ 2 Perl_sv_catpvn(pTHX_ register SV *sv, register const char *ptr, register STRLEN len)
+ 3 {
+ 4 STRLEN tlen;
+ 5 char *junk;
+
+ 6 junk = SvPV_force(sv, tlen);
+ 7 SvGROW(sv, tlen + len + 1);
+ 8 if (ptr == junk)
+ 9 ptr = SvPVX(sv);
+ 10 Move(ptr,SvPVX(sv)+tlen,len,char);
+ 11 SvCUR(sv) += len;
+ 12 *SvEND(sv) = '\0';
+ 13 (void)SvPOK_only_UTF8(sv); /* validate pointer */
+ 14 SvTAINT(sv);
+ 15 }
+
+This is a function which adds a string, C<ptr>, of length C<len> onto
+the end of the PV stored in C<sv>. The first thing we do in line 6 is
+make sure that the SV B<has> a valid PV, by calling the C<SvPV_force>
+macro to force a PV. As a side effect, C<tlen> gets set to the current
+value of the PV, and the PV itself is returned to C<junk>.
+
+In line 7, we make sure that the SV will have enough room to accommodate
+the old string, the new string and the null terminator. If C<LEN> isn't
+big enough, C<SvGROW> will reallocate space for us.
+
+Now, if C<junk> is the same as the string we're trying to add, we can
+grab the string directly from the SV; C<SvPVX> is the address of the PV
+in the SV.
+
+Line 10 does the actual catenation: the C<Move> macro moves a chunk of
+memory around: we move the string C<ptr> to the end of the PV - that's
+the start of the PV plus its current length. We're moving C<len> bytes
+of type C<char>. After doing so, we need to tell Perl we've extended the
+string, by altering C<CUR> to reflect the new length. C<SvEND> is a
+macro which gives us the end of the string, so that needs to be a
+C<"\0">.
+
+Line 13 manipulates the flags; since we've changed the PV, any IV or NV
+values will no longer be valid: if we have C<$a=10; $a.="6";> we don't
+want to use the old IV of 10. C<SvPOK_only_utf8> is a special UTF-8-aware
+version of C<SvPOK_only>, a macro which turns off the IOK and NOK flags
+and turns on POK. The final C<SvTAINT> is a macro which launders tainted
+data if taint mode is turned on.
+
+AVs and HVs are more complicated, but SVs are by far the most common
+variable type being thrown around. Having seen something of how we
+manipulate these, let's go on and look at how the op tree is
+constructed.
+
+=head2 Op Trees
+
+First, what is the op tree, anyway? The op tree is the parsed
+representation of your program, as we saw in our section on parsing, and
+it's the sequence of operations that Perl goes through to execute your
+program, as we saw in L</Running>.
+
+An op is a fundamental operation that Perl can perform: all the built-in
+functions and operators are ops, and there are a series of ops which
+deal with concepts the interpreter needs internally - entering and
+leaving a block, ending a statement, fetching a variable, and so on.
+
+The op tree is connected in two ways: you can imagine that there are two
+"routes" through it, two orders in which you can traverse the tree.
+First, parse order reflects how the parser understood the code, and
+secondly, execution order tells perl what order to perform the
+operations in.
+
+The easiest way to examine the op tree is to stop Perl after it has
+finished parsing, and get it to dump out the tree. This is exactly what
+the compiler backends L<B::Terse|B::Terse>, L<B::Concise|B::Concise>
+and L<B::Debug|B::Debug> do.
+
+Let's have a look at how Perl sees C<$a = $b + $c>:
+
+ % perl -MO=Terse -e '$a=$b+$c'
+ 1 LISTOP (0x8179888) leave
+ 2 OP (0x81798b0) enter
+ 3 COP (0x8179850) nextstate
+ 4 BINOP (0x8179828) sassign
+ 5 BINOP (0x8179800) add [1]
+ 6 UNOP (0x81796e0) null [15]
+ 7 SVOP (0x80fafe0) gvsv GV (0x80fa4cc) *b
+ 8 UNOP (0x81797e0) null [15]
+ 9 SVOP (0x8179700) gvsv GV (0x80efeb0) *c
+ 10 UNOP (0x816b4f0) null [15]
+ 11 SVOP (0x816dcf0) gvsv GV (0x80fa460) *a
+
+Let's start in the middle, at line 4. This is a BINOP, a binary
+operator, which is at location C<0x8179828>. The specific operator in
+question is C<sassign> - scalar assignment - and you can find the code
+which implements it in the function C<pp_sassign> in F<pp_hot.c>. As a
+binary operator, it has two children: the add operator, providing the
+result of C<$b+$c>, is uppermost on line 5, and the left hand side is on
+line 10.
+
+Line 10 is the null op: this does exactly nothing. What is that doing
+there? If you see the null op, it's a sign that something has been
+optimized away after parsing. As we mentioned in L</Optimization>,
+the optimization stage sometimes converts two operations into one, for
+example when fetching a scalar variable. When this happens, instead of
+rewriting the op tree and cleaning up the dangling pointers, it's easier
+just to replace the redundant operation with the null op. Originally,
+the tree would have looked like this:
+
+ 10 SVOP (0x816b4f0) rv2sv [15]
+ 11 SVOP (0x816dcf0) gv GV (0x80fa460) *a
+
+That is, fetch the C<a> entry from the main symbol table, and then look
+at the scalar component of it: C<gvsv> (C<pp_gvsv> into F<pp_hot.c>)
+happens to do both these things.
+
+The right hand side, starting at line 5 is similar to what we've just
+seen: we have the C<add> op (C<pp_add> also in F<pp_hot.c>) add together
+two C<gvsv>s.
+
+Now, what's this about?
+
+ 1 LISTOP (0x8179888) leave
+ 2 OP (0x81798b0) enter
+ 3 COP (0x8179850) nextstate
+
+C<enter> and C<leave> are scoping ops, and their job is to perform any
+housekeeping every time you enter and leave a block: lexical variables
+are tidied up, unreferenced variables are destroyed, and so on. Every
+program will have those first three lines: C<leave> is a list, and its
+children are all the statements in the block. Statements are delimited
+by C<nextstate>, so a block is a collection of C<nextstate> ops, with
+the ops to be performed for each statement being the children of
+C<nextstate>. C<enter> is a single op which functions as a marker.
+
+That's how Perl parsed the program, from top to bottom:
+
+ Program
+ |
+ Statement
+ |
+ =
+ / \
+ / \
+ $a +
+ / \
+ $b $c
+
+However, it's impossible to B<perform> the operations in this order:
+you have to find the values of C<$b> and C<$c> before you add them
+together, for instance. So, the other thread that runs through the op
+tree is the execution order: each op has a field C<op_next> which points
+to the next op to be run, so following these pointers tells us how perl
+executes the code. We can traverse the tree in this order using
+the C<exec> option to C<B::Terse>:
+
+ % perl -MO=Terse,exec -e '$a=$b+$c'
+ 1 OP (0x8179928) enter
+ 2 COP (0x81798c8) nextstate
+ 3 SVOP (0x81796c8) gvsv GV (0x80fa4d4) *b
+ 4 SVOP (0x8179798) gvsv GV (0x80efeb0) *c
+ 5 BINOP (0x8179878) add [1]
+ 6 SVOP (0x816dd38) gvsv GV (0x80fa468) *a
+ 7 BINOP (0x81798a0) sassign
+ 8 LISTOP (0x8179900) leave
+
+This probably makes more sense for a human: enter a block, start a
+statement. Get the values of C<$b> and C<$c>, and add them together.
+Find C<$a>, and assign one to the other. Then leave.
+
+The way Perl builds up these op trees in the parsing process can be
+unravelled by examining F<perly.y>, the YACC grammar. Let's take the
+piece we need to construct the tree for C<$a = $b + $c>
+
+ 1 term : term ASSIGNOP term
+ 2 { $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
+ 3 | term ADDOP term
+ 4 { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
+
+If you're not used to reading BNF grammars, this is how it works: You're
+fed certain things by the tokeniser, which generally end up in upper
+case. Here, C<ADDOP>, is provided when the tokeniser sees C<+> in your
+code. C<ASSIGNOP> is provided when C<=> is used for assigning. These are
+"terminal symbols", because you can't get any simpler than them.
+
+The grammar, lines one and three of the snippet above, tells you how to
+build up more complex forms. These complex forms, "non-terminal symbols"
+are generally placed in lower case. C<term> here is a non-terminal
+symbol, representing a single expression.
+
+The grammar gives you the following rule: you can make the thing on the
+left of the colon if you see all the things on the right in sequence.
+This is called a "reduction", and the aim of parsing is to completely
+reduce the input. There are several different ways you can perform a
+reduction, separated by vertical bars: so, C<term> followed by C<=>
+followed by C<term> makes a C<term>, and C<term> followed by C<+>
+followed by C<term> can also make a C<term>.
+
+So, if you see two terms with an C<=> or C<+>, between them, you can
+turn them into a single expression. When you do this, you execute the
+code in the block on the next line: if you see C<=>, you'll do the code
+in line 2. If you see C<+>, you'll do the code in line 4. It's this code
+which contributes to the op tree.
+
+ | term ADDOP term
+ { $$ = newBINOP($2, 0, scalar($1), scalar($3)); }
+
+What this does is creates a new binary op, and feeds it a number of
+variables. The variables refer to the tokens: C<$1> is the first token in
+the input, C<$2> the second, and so on - think regular expression
+backreferences. C<$$> is the op returned from this reduction. So, we
+call C<newBINOP> to create a new binary operator. The first parameter to
+C<newBINOP>, a function in F<op.c>, is the op type. It's an addition
+operator, so we want the type to be C<ADDOP>. We could specify this
+directly, but it's right there as the second token in the input, so we
+use C<$2>. The second parameter is the op's flags: 0 means "nothing
+special". Then the things to add: the left and right hand side of our
+expression, in scalar context.
+
+=head2 Stacks
+
+When perl executes something like C<addop>, how does it pass on its
+results to the next op? The answer is, through the use of stacks. Perl
+has a number of stacks to store things it's currently working on, and
+we'll look at the three most important ones here.
+
+=over 3
+
+=item Argument stack
+
+Arguments are passed to PP code and returned from PP code using the
+argument stack, C<ST>. The typical way to handle arguments is to pop
+them off the stack, deal with them how you wish, and then push the result
+back onto the stack. This is how, for instance, the cosine operator
+works:
+
+ NV value;
+ value = POPn;
+ value = Perl_cos(value);
+ XPUSHn(value);
+
+We'll see a more tricky example of this when we consider Perl's macros
+below. C<POPn> gives you the NV (floating point value) of the top SV on
+the stack: the C<$x> in C<cos($x)>. Then we compute the cosine, and push
+the result back as an NV. The C<X> in C<XPUSHn> means that the stack
+should be extended if necessary - it can't be necessary here, because we
+know there's room for one more item on the stack, since we've just
+removed one! The C<XPUSH*> macros at least guarantee safety.
+
+Alternatively, you can fiddle with the stack directly: C<SP> gives you
+the first element in your portion of the stack, and C<TOP*> gives you
+the top SV/IV/NV/etc. on the stack. So, for instance, to do unary
+negation of an integer:
+
+ SETi(-TOPi);
+
+Just set the integer value of the top stack entry to its negation.
+
+Argument stack manipulation in the core is exactly the same as it is in
+XSUBs - see L<perlxstut>, L<perlxs> and L<perlguts> for a longer
+description of the macros used in stack manipulation.
+
+=item Mark stack
+
+I say "your portion of the stack" above because PP code doesn't
+necessarily get the whole stack to itself: if your function calls
+another function, you'll only want to expose the arguments aimed for the
+called function, and not (necessarily) let it get at your own data. The
+way we do this is to have a "virtual" bottom-of-stack, exposed to each
+function. The mark stack keeps bookmarks to locations in the argument
+stack usable by each function. For instance, when dealing with a tied
+variable, (internally, something with "P" magic) Perl has to call
+methods for accesses to the tied variables. However, we need to separate
+the arguments exposed to the method to the argument exposed to the
+original function - the store or fetch or whatever it may be. Here's
+roughly how the tied C<push> is implemented; see C<av_push> in F<av.c>:
+
+ 1 PUSHMARK(SP);
+ 2 EXTEND(SP,2);
+ 3 PUSHs(SvTIED_obj((SV*)av, mg));
+ 4 PUSHs(val);
+ 5 PUTBACK;
+ 6 ENTER;
+ 7 call_method("PUSH", G_SCALAR|G_DISCARD);
+ 8 LEAVE;
+
+Let's examine the whole implementation, for practice:
+
+ 1 PUSHMARK(SP);
+
+Push the current state of the stack pointer onto the mark stack. This is
+so that when we've finished adding items to the argument stack, Perl
+knows how many things we've added recently.
+
+ 2 EXTEND(SP,2);
+ 3 PUSHs(SvTIED_obj((SV*)av, mg));
+ 4 PUSHs(val);
+
+We're going to add two more items onto the argument stack: when you have
+a tied array, the C<PUSH> subroutine receives the object and the value
+to be pushed, and that's exactly what we have here - the tied object,
+retrieved with C<SvTIED_obj>, and the value, the SV C<val>.
+
+ 5 PUTBACK;
+
+Next we tell Perl to update the global stack pointer from our internal
+variable: C<dSP> only gave us a local copy, not a reference to the global.
+
+ 6 ENTER;
+ 7 call_method("PUSH", G_SCALAR|G_DISCARD);
+ 8 LEAVE;
+
+C<ENTER> and C<LEAVE> localise a block of code - they make sure that all
+variables are tidied up, everything that has been localised gets
+its previous value returned, and so on. Think of them as the C<{> and
+C<}> of a Perl block.
+
+To actually do the magic method call, we have to call a subroutine in
+Perl space: C<call_method> takes care of that, and it's described in
+L<perlcall>. We call the C<PUSH> method in scalar context, and we're
+going to discard its return value. The call_method() function
+removes the top element of the mark stack, so there is nothing for
+the caller to clean up.
+
+=item Save stack
+
+C doesn't have a concept of local scope, so perl provides one. We've
+seen that C<ENTER> and C<LEAVE> are used as scoping braces; the save
+stack implements the C equivalent of, for example:
+
+ {
+ local $foo = 42;
+ ...
+ }
+
+See L<perlguts/Localising Changes> for how to use the save stack.
+
+=back
+
+=head2 Millions of Macros
+
+One thing you'll notice about the Perl source is that it's full of
+macros. Some have called the pervasive use of macros the hardest thing
+to understand, others find it adds to clarity. Let's take an example,
+the code which implements the addition operator:
+
+ 1 PP(pp_add)
+ 2 {
+ 3 dSP; dATARGET; tryAMAGICbin(add,opASSIGN);
+ 4 {
+ 5 dPOPTOPnnrl_ul;
+ 6 SETn( left + right );
+ 7 RETURN;
+ 8 }
+ 9 }
+
+Every line here (apart from the braces, of course) contains a macro. The
+first line sets up the function declaration as Perl expects for PP code;
+line 3 sets up variable declarations for the argument stack and the
+target, the return value of the operation. Finally, it tries to see if
+the addition operation is overloaded; if so, the appropriate subroutine
+is called.
+
+Line 5 is another variable declaration - all variable declarations start
+with C<d> - which pops from the top of the argument stack two NVs (hence
+C<nn>) and puts them into the variables C<right> and C<left>, hence the
+C<rl>. These are the two operands to the addition operator. Next, we
+call C<SETn> to set the NV of the return value to the result of adding
+the two values. This done, we return - the C<RETURN> macro makes sure
+that our return value is properly handled, and we pass the next operator
+to run back to the main run loop.
+
+Most of these macros are explained in L<perlapi>, and some of the more
+important ones are explained in L<perlxs> as well. Pay special attention
+to L<perlguts/Background and PERL_IMPLICIT_CONTEXT> for information on
+the C<[pad]THX_?> macros.
+
+=head2 The .i Targets
+
+You can expand the macros in a F<foo.c> file by saying
+
+ make foo.i
+
+which will expand the macros using cpp. Don't be scared by the results.
+
+=head1 SOURCE CODE STATIC ANALYSIS
+
+Various tools exist for analysing C source code B<statically>, as
+opposed to B<dynamically>, that is, without executing the code.
+It is possible to detect resource leaks, undefined behaviour, type
+mismatches, portability problems, code paths that would cause illegal
+memory accesses, and other similar problems by just parsing the C code
+and looking at the resulting graph, what does it tell about the
+execution and data flows. As a matter of fact, this is exactly
+how C compilers know to give warnings about dubious code.
+
+=head2 lint, splint
+
+The good old C code quality inspector, C<lint>, is available in
+several platforms, but please be aware that there are several
+different implementations of it by different vendors, which means that
+the flags are not identical across different platforms.
+
+There is a lint variant called C<splint> (Secure Programming Lint)
+available from http://www.splint.org/ that should compile on any
+Unix-like platform.
+
+There are C<lint> and <splint> targets in Makefile, but you may have
+to diddle with the flags (see above).
+
+=head2 Coverity
+
+Coverity (http://www.coverity.com/) is a product similar to lint and
+as a testbed for their product they periodically check several open
+source projects, and they give out accounts to open source developers
+to the defect databases.
+
+=head2 cpd (cut-and-paste detector)
+
+The cpd tool detects cut-and-paste coding. If one instance of the
+cut-and-pasted code changes, all the other spots should probably be
+changed, too. Therefore such code should probably be turned into a
+subroutine or a macro.
+
+cpd (http://pmd.sourceforge.net/cpd.html) is part of the pmd project
+(http://pmd.sourceforge.net/). pmd was originally written for static
+analysis of Java code, but later the cpd part of it was extended to
+parse also C and C++.
+
+Download the pmd-bin-X.Y.zip () from the SourceForge site, extract the
+pmd-X.Y.jar from it, and then run that on source code thusly:
+
+ java -cp pmd-X.Y.jar net.sourceforge.pmd.cpd.CPD --minimum-tokens 100 --files /some/where/src --language c > cpd.txt
+
+You may run into memory limits, in which case you should use the -Xmx option:
+
+ java -Xmx512M ...
+
+=head2 gcc warnings
+
+Though much can be written about the inconsistency and coverage
+problems of gcc warnings (like C<-Wall> not meaning "all the
+warnings", or some common portability problems not being covered by
+C<-Wall>, or C<-ansi> and C<-pedantic> both being a poorly defined
+collection of warnings, and so forth), gcc is still a useful tool in
+keeping our coding nose clean.
+
+The C<-Wall> is by default on.
+
+The C<-ansi> (and its sidekick, C<-pedantic>) would be nice to be on
+always, but unfortunately they are not safe on all platforms, they can
+for example cause fatal conflicts with the system headers (Solaris
+being a prime example). If Configure C<-Dgccansipedantic> is used,
+the C<cflags> frontend selects C<-ansi -pedantic> for the platforms
+where they are known to be safe.
+
+Starting from Perl 5.9.4 the following extra flags are added:
+
+=over 4
+
+=item *
+
+C<-Wendif-labels>
+
+=item *
+
+C<-Wextra>
+
+=item *
+
+C<-Wdeclaration-after-statement>
+
+=back
+
+The following flags would be nice to have but they would first need
+their own Augean stablemaster:
+
+=over 4
+
+=item *
+
+C<-Wpointer-arith>
+
+=item *
+
+C<-Wshadow>
+
+=item *
+
+C<-Wstrict-prototypes>
+
+=back
+
+The C<-Wtraditional> is another example of the annoying tendency of
+gcc to bundle a lot of warnings under one switch (it would be
+impossible to deploy in practice because it would complain a lot) but
+it does contain some warnings that would be beneficial to have available
+on their own, such as the warning about string constants inside macros
+containing the macro arguments: this behaved differently pre-ANSI
+than it does in ANSI, and some C compilers are still in transition,
+AIX being an example.
+
+=head2 Warnings of other C compilers
+
+Other C compilers (yes, there B<are> other C compilers than gcc) often
+have their "strict ANSI" or "strict ANSI with some portability extensions"
+modes on, like for example the Sun Workshop has its C<-Xa> mode on
+(though implicitly), or the DEC (these days, HP...) has its C<-std1>
+mode on.
+
+=head2 DEBUGGING
+
+You can compile a special debugging version of Perl, which allows you
+to use the C<-D> option of Perl to tell more about what Perl is doing.
+But sometimes there is no alternative than to dive in with a debugger,
+either to see the stack trace of a core dump (very useful in a bug
+report), or trying to figure out what went wrong before the core dump
+happened, or how did we end up having wrong or unexpected results.
+
+=head2 Poking at Perl
+
+To really poke around with Perl, you'll probably want to build Perl for
+debugging, like this:
+
+ ./Configure -d -D optimize=-g
+ make
+
+C<-g> is a flag to the C compiler to have it produce debugging
+information which will allow us to step through a running program,
+and to see in which C function we are at (without the debugging
+information we might see only the numerical addresses of the functions,
+which is not very helpful).
+
+F<Configure> will also turn on the C<DEBUGGING> compilation symbol which
+enables all the internal debugging code in Perl. There are a whole bunch
+of things you can debug with this: L<perlrun> lists them all, and the
+best way to find out about them is to play about with them. The most
+useful options are probably
+
+ l Context (loop) stack processing
+ t Trace execution
+ o Method and overloading resolution
+ c String/numeric conversions
+
+Some of the functionality of the debugging code can be achieved using XS
+modules.
+
+ -Dr => use re 'debug'
+ -Dx => use O 'Debug'
+
+=head2 Using a source-level debugger
+
+If the debugging output of C<-D> doesn't help you, it's time to step
+through perl's execution with a source-level debugger.
+
+=over 3
+
+=item *
+
+We'll use C<gdb> for our examples here; the principles will apply to
+any debugger (many vendors call their debugger C<dbx>), but check the
+manual of the one you're using.
+
+=back
+
+To fire up the debugger, type
+
+ gdb ./perl
+
+Or if you have a core dump:
+
+ gdb ./perl core
+
+You'll want to do that in your Perl source tree so the debugger can read
+the source code. You should see the copyright message, followed by the
+prompt.
+
+ (gdb)
+
+C<help> will get you into the documentation, but here are the most
+useful commands:
+
+=over 3
+
+=item run [args]
+
+Run the program with the given arguments.
+
+=item break function_name
+
+=item break source.c:xxx
+
+Tells the debugger that we'll want to pause execution when we reach
+either the named function (but see L<perlguts/Internal Functions>!) or the given
+line in the named source file.
+
+=item step
+
+Steps through the program a line at a time.
+
+=item next
+
+Steps through the program a line at a time, without descending into
+functions.
+
+=item continue
+
+Run until the next breakpoint.
+
+=item finish
+
+Run until the end of the current function, then stop again.
+
+=item 'enter'
+
+Just pressing Enter will do the most recent operation again - it's a
+blessing when stepping through miles of source code.
+
+=item print
+
+Execute the given C code and print its results. B<WARNING>: Perl makes
+heavy use of macros, and F<gdb> does not necessarily support macros
+(see later L</"gdb macro support">). You'll have to substitute them
+yourself, or to invoke cpp on the source code files
+(see L</"The .i Targets">)
+So, for instance, you can't say
+
+ print SvPV_nolen(sv)
+
+but you have to say
+
+ print Perl_sv_2pv_nolen(sv)
+
+=back
+
+You may find it helpful to have a "macro dictionary", which you can
+produce by saying C<cpp -dM perl.c | sort>. Even then, F<cpp> won't
+recursively apply those macros for you.
+
+=head2 gdb macro support
+
+Recent versions of F<gdb> have fairly good macro support, but
+in order to use it you'll need to compile perl with macro definitions
+included in the debugging information. Using F<gcc> version 3.1, this
+means configuring with C<-Doptimize=-g3>. Other compilers might use a
+different switch (if they support debugging macros at all).
+
+=head2 Dumping Perl Data Structures
+
+One way to get around this macro hell is to use the dumping functions in
+F<dump.c>; these work a little like an internal
+L<Devel::Peek|Devel::Peek>, but they also cover OPs and other structures
+that you can't get at from Perl. Let's take an example. We'll use the
+C<$a = $b + $c> we used before, but give it a bit of context:
+C<$b = "6XXXX"; $c = 2.3;>. Where's a good place to stop and poke around?
+
+What about C<pp_add>, the function we examined earlier to implement the
+C<+> operator:
+
+ (gdb) break Perl_pp_add
+ Breakpoint 1 at 0x46249f: file pp_hot.c, line 309.
+
+Notice we use C<Perl_pp_add> and not C<pp_add> - see L<perlguts/Internal Functions>.
+With the breakpoint in place, we can run our program:
+
+ (gdb) run -e '$b = "6XXXX"; $c = 2.3; $a = $b + $c'
+
+Lots of junk will go past as gdb reads in the relevant source files and
+libraries, and then:
+
+ Breakpoint 1, Perl_pp_add () at pp_hot.c:309
+ 309 dSP; dATARGET; tryAMAGICbin(add,opASSIGN);
+ (gdb) step
+ 311 dPOPTOPnnrl_ul;
+ (gdb)
+
+We looked at this bit of code before, and we said that C<dPOPTOPnnrl_ul>
+arranges for two C<NV>s to be placed into C<left> and C<right> - let's
+slightly expand it:
+
+ #define dPOPTOPnnrl_ul NV right = POPn; \
+ SV *leftsv = TOPs; \
+ NV left = USE_LEFT(leftsv) ? SvNV(leftsv) : 0.0
+
+C<POPn> takes the SV from the top of the stack and obtains its NV either
+directly (if C<SvNOK> is set) or by calling the C<sv_2nv> function.
+C<TOPs> takes the next SV from the top of the stack - yes, C<POPn> uses
+C<TOPs> - but doesn't remove it. We then use C<SvNV> to get the NV from
+C<leftsv> in the same way as before - yes, C<POPn> uses C<SvNV>.
+
+Since we don't have an NV for C<$b>, we'll have to use C<sv_2nv> to
+convert it. If we step again, we'll find ourselves there:
+
+ Perl_sv_2nv (sv=0xa0675d0) at sv.c:1669
+ 1669 if (!sv)
+ (gdb)
+
+We can now use C<Perl_sv_dump> to investigate the SV:
+
+ SV = PV(0xa057cc0) at 0xa0675d0
+ REFCNT = 1
+ FLAGS = (POK,pPOK)
+ PV = 0xa06a510 "6XXXX"\0
+ CUR = 5
+ LEN = 6
+ $1 = void
+
+We know we're going to get C<6> from this, so let's finish the
+subroutine:
+
+ (gdb) finish
+ Run till exit from #0 Perl_sv_2nv (sv=0xa0675d0) at sv.c:1671
+ 0x462669 in Perl_pp_add () at pp_hot.c:311
+ 311 dPOPTOPnnrl_ul;
+
+We can also dump out this op: the current op is always stored in
+C<PL_op>, and we can dump it with C<Perl_op_dump>. This'll give us
+similar output to L<B::Debug|B::Debug>.
+
+ {
+ 13 TYPE = add ===> 14
+ TARG = 1
+ FLAGS = (SCALAR,KIDS)
+ {
+ TYPE = null ===> (12)
+ (was rv2sv)
+ FLAGS = (SCALAR,KIDS)
+ {
+ 11 TYPE = gvsv ===> 12
+ FLAGS = (SCALAR)
+ GV = main::b
+ }
+ }
+
+# finish this later #
+
+=head2 Patching
+
+All right, we've now had a look at how to navigate the Perl sources and
+some things you'll need to know when fiddling with them. Let's now get
+on and create a simple patch. Here's something Larry suggested: if a
+C<U> is the first active format during a C<pack>, (for example,
+C<pack "U3C8", @stuff>) then the resulting string should be treated as
+UTF-8 encoded.
+
+If you are working with a git clone of the Perl repository, you will want to
+create a branch for your changes. This will make creating a proper patch much
+simpler. See the L<perlrepository> for details on how to do this.
+
+How do we prepare to fix this up? First we locate the code in question -
+the C<pack> happens at runtime, so it's going to be in one of the F<pp>
+files. Sure enough, C<pp_pack> is in F<pp.c>. Since we're going to be
+altering this file, let's copy it to F<pp.c~>.
+
+[Well, it was in F<pp.c> when this tutorial was written. It has now been
+split off with C<pp_unpack> to its own file, F<pp_pack.c>]
+
+Now let's look over C<pp_pack>: we take a pattern into C<pat>, and then
+loop over the pattern, taking each format character in turn into
+C<datum_type>. Then for each possible format character, we swallow up
+the other arguments in the pattern (a field width, an asterisk, and so
+on) and convert the next chunk input into the specified format, adding
+it onto the output SV C<cat>.
+
+How do we know if the C<U> is the first format in the C<pat>? Well, if
+we have a pointer to the start of C<pat> then, if we see a C<U> we can
+test whether we're still at the start of the string. So, here's where
+C<pat> is set up:
+
+ STRLEN fromlen;
+ register char *pat = SvPVx(*++MARK, fromlen);
+ register char *patend = pat + fromlen;
+ register I32 len;
+ I32 datumtype;
+ SV *fromstr;
+
+We'll have another string pointer in there:
+
+ STRLEN fromlen;
+ register char *pat = SvPVx(*++MARK, fromlen);
+ register char *patend = pat + fromlen;
+ + char *patcopy;
+ register I32 len;
+ I32 datumtype;
+ SV *fromstr;
+
+And just before we start the loop, we'll set C<patcopy> to be the start
+of C<pat>:
+
+ items = SP - MARK;
+ MARK++;
+ sv_setpvn(cat, "", 0);
+ + patcopy = pat;
+ while (pat < patend) {
+
+Now if we see a C<U> which was at the start of the string, we turn on
+the C<UTF8> flag for the output SV, C<cat>:
+
+ + if (datumtype == 'U' && pat==patcopy+1)
+ + SvUTF8_on(cat);
+ if (datumtype == '#') {
+ while (pat < patend && *pat != '\n')
+ pat++;
+
+Remember that it has to be C<patcopy+1> because the first character of
+the string is the C<U> which has been swallowed into C<datumtype!>
+
+Oops, we forgot one thing: what if there are spaces at the start of the
+pattern? C<pack(" U*", @stuff)> will have C<U> as the first active
+character, even though it's not the first thing in the pattern. In this
+case, we have to advance C<patcopy> along with C<pat> when we see spaces:
+
+ if (isSPACE(datumtype))
+ continue;
+
+needs to become
+
+ if (isSPACE(datumtype)) {
+ patcopy++;
+ continue;
+ }
+
+OK. That's the C part done. Now we must do two additional things before
+this patch is ready to go: we've changed the behaviour of Perl, and so
+we must document that change. We must also provide some more regression
+tests to make sure our patch works and doesn't create a bug somewhere
+else along the line.
+
+The regression tests for each operator live in F<t/op/>, and so we
+make a copy of F<t/op/pack.t> to F<t/op/pack.t~>. Now we can add our
+tests to the end. First, we'll test that the C<U> does indeed create
+Unicode strings.
+
+t/op/pack.t has a sensible ok() function, but if it didn't we could
+use the one from t/test.pl.
+
+ require './test.pl';
+ plan( tests => 159 );
+
+so instead of this:
+
+ print 'not ' unless "1.20.300.4000" eq sprintf "%vd",
+ pack("U*",1,20,300,4000);
+ print "ok $test\n"; $test++;
+
+we can write the more sensible (see L<Test::More> for a full
+explanation of is() and other testing functions).
+
+ is( "1.20.300.4000", sprintf "%vd", pack("U*",1,20,300,4000),
+ "U* produces Unicode" );
+
+Now we'll test that we got that space-at-the-beginning business right:
+
+ is( "1.20.300.4000", sprintf "%vd", pack(" U*",1,20,300,4000),
+ " with spaces at the beginning" );
+
+And finally we'll test that we don't make Unicode strings if C<U> is B<not>
+the first active format:
+
+ isnt( v1.20.300.4000, sprintf "%vd", pack("C0U*",1,20,300,4000),
+ "U* not first isn't Unicode" );
+
+Mustn't forget to change the number of tests which appears at the top,
+or else the automated tester will get confused. This will either look
+like this:
+
+ print "1..156\n";
+
+or this:
+
+ plan( tests => 156 );
+
+We now compile up Perl, and run it through the test suite. Our new
+tests pass, hooray!
+
+Finally, the documentation. The job is never done until the paperwork is
+over, so let's describe the change we've just made. The relevant place
+is F<pod/perlfunc.pod>; again, we make a copy, and then we'll insert
+this text in the description of C<pack>:
+
+ =item *
+
+ If the pattern begins with a C<U>, the resulting string will be treated
+ as UTF-8-encoded Unicode. You can force UTF-8 encoding on in a string
+ with an initial C<U0>, and the bytes that follow will be interpreted as
+ Unicode characters. If you don't want this to happen, you can begin
+ your pattern with C<C0> (or anything else) to force Perl not to UTF-8
+ encode your string, and then follow this with a C<U*> somewhere in your
+ pattern.
+
+=head2 Patching a core module
+
+This works just like patching anything else, with an extra
+consideration. Many core modules also live on CPAN. If this is so,
+patch the CPAN version instead of the core and send the patch off to
+the module maintainer (with a copy to p5p). This will help the module
+maintainer keep the CPAN version in sync with the core version without
+constantly scanning p5p.
+
+The list of maintainers of core modules is usefully documented in
+F<Porting/Maintainers.pl>.
+
+=head2 Adding a new function to the core
+
+If, as part of a patch to fix a bug, or just because you have an
+especially good idea, you decide to add a new function to the core,
+discuss your ideas on p5p well before you start work. It may be that
+someone else has already attempted to do what you are considering and
+can give lots of good advice or even provide you with bits of code
+that they already started (but never finished).
+
+You have to follow all of the advice given above for patching. It is
+extremely important to test any addition thoroughly and add new tests
+to explore all boundary conditions that your new function is expected
+to handle. If your new function is used only by one module (e.g. toke),
+then it should probably be named S_your_function (for static); on the
+other hand, if you expect it to accessible from other functions in
+Perl, you should name it Perl_your_function. See L<perlguts/Internal Functions>
+for more details.
+
+The location of any new code is also an important consideration. Don't
+just create a new top level .c file and put your code there; you would
+have to make changes to Configure (so the Makefile is created properly),
+as well as possibly lots of include files. This is strictly pumpking
+business.
+
+It is better to add your function to one of the existing top level
+source code files, but your choice is complicated by the nature of
+the Perl distribution. Only the files that are marked as compiled
+static are located in the perl executable. Everything else is located
+in the shared library (or DLL if you are running under WIN32). So,
+for example, if a function was only used by functions located in
+toke.c, then your code can go in toke.c. If, however, you want to call
+the function from universal.c, then you should put your code in another
+location, for example util.c.
+
+In addition to writing your c-code, you will need to create an
+appropriate entry in embed.pl describing your function, then run
+'make regen_headers' to create the entries in the numerous header
+files that perl needs to compile correctly. See L<perlguts/Internal Functions>
+for information on the various options that you can set in embed.pl.
+You will forget to do this a few (or many) times and you will get
+warnings during the compilation phase. Make sure that you mention
+this when you post your patch to P5P; the pumpking needs to know this.
+
+When you write your new code, please be conscious of existing code
+conventions used in the perl source files. See L<perlstyle> for
+details. Although most of the guidelines discussed seem to focus on
+Perl code, rather than c, they all apply (except when they don't ;).
+Also see L<perlrepository> for lots of details about both formatting and
+submitting patches of your changes.
+
+Lastly, TEST TEST TEST TEST TEST any code before posting to p5p.
+Test on as many platforms as you can find. Test as many perl
+Configure options as you can (e.g. MULTIPLICITY). If you have
+profiling or memory tools, see L<EXTERNAL TOOLS FOR DEBUGGING PERL>
+below for how to use them to further test your code. Remember that
+most of the people on P5P are doing this on their own time and
+don't have the time to debug your code.
+
+=head2 Writing a test
+
+Every module and built-in function has an associated test file (or
+should...). If you add or change functionality, you have to write a
+test. If you fix a bug, you have to write a test so that bug never
+comes back. If you alter the docs, it would be nice to test what the
+new documentation says.
+
+In short, if you submit a patch you probably also have to patch the
+tests.
+
+For modules, the test file is right next to the module itself.
+F<lib/strict.t> tests F<lib/strict.pm>. This is a recent innovation,
+so there are some snags (and it would be wonderful for you to brush
+them out), but it basically works that way. Everything else lives in
+F<t/>.
+
+If you add a new test directory under F<t/>, it is imperative that you
+add that directory to F<t/HARNESS> and F<t/TEST>.
+
+=over 3
+
+=item F<t/base/>
+
+Testing of the absolute basic functionality of Perl. Things like
+C<if>, basic file reads and writes, simple regexes, etc. These are
+run first in the test suite and if any of them fail, something is
+I<really> broken.
+
+=item F<t/cmd/>
+
+These test the basic control structures, C<if/else>, C<while>,
+subroutines, etc.
+
+=item F<t/comp/>
+
+Tests basic issues of how Perl parses and compiles itself.
+
+=item F<t/io/>
+
+Tests for built-in IO functions, including command line arguments.
+
+=item F<t/lib/>
+
+The old home for the module tests, you shouldn't put anything new in
+here. There are still some bits and pieces hanging around in here
+that need to be moved. Perhaps you could move them? Thanks!
+
+=item F<t/mro/>
+
+Tests for perl's method resolution order implementations
+(see L<mro>).
+
+=item F<t/op/>
+
+Tests for perl's built in functions that don't fit into any of the
+other directories.
+
+=item F<t/re/>
+
+Tests for regex related functions or behaviour. (These used to live
+in t/op).
+
+=item F<t/run/>
+
+Testing features of how perl actually runs, including exit codes and
+handling of PERL* environment variables.
+
+=item F<t/uni/>
+
+Tests for the core support of Unicode.
+
+=item F<t/win32/>
+
+Windows-specific tests.
+
+=item F<t/x2p>
+
+A test suite for the s2p converter.
+
+=back
+
+The core uses the same testing style as the rest of Perl, a simple
+"ok/not ok" run through Test::Harness, but there are a few special
+considerations.
+
+There are three ways to write a test in the core. Test::More,
+t/test.pl and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. The
+decision of which to use depends on what part of the test suite you're
+working on. This is a measure to prevent a high-level failure (such
+as Config.pm breaking) from causing basic functionality tests to fail.
+If you write your own test, use the L<Test Anything Protocol|TAP>.
+
+=over 4
+
+=item t/base t/comp
+
+Since we don't know if require works, or even subroutines, use ad hoc
+tests for these two. Step carefully to avoid using the feature being
+tested.
+
+=item t/cmd t/run t/io t/op
+
+Now that basic require() and subroutines are tested, you can use the
+t/test.pl library which emulates the important features of Test::More
+while using a minimum of core features.
+
+You can also conditionally use certain libraries like Config, but be
+sure to skip the test gracefully if it's not there.
+
+=item t/lib ext lib
+
+Now that the core of Perl is tested, Test::More can be used. You can
+also use the full suite of core modules in the tests.
+
+=back
+
+When you say "make test" Perl uses the F<t/TEST> program to run the
+test suite (except under Win32 where it uses F<t/harness> instead.)
+All tests are run from the F<t/> directory, B<not> the directory
+which contains the test. This causes some problems with the tests
+in F<lib/>, so here's some opportunity for some patching.
+
+You must be triply conscious of cross-platform concerns. This usually
+boils down to using File::Spec and avoiding things like C<fork()> and
+C<system()> unless absolutely necessary.
+
+=head2 Special Make Test Targets
+
+There are various special make targets that can be used to test Perl
+slightly differently than the standard "test" target. Not all them
+are expected to give a 100% success rate. Many of them have several
+aliases, and many of them are not available on certain operating
+systems.
+
+=over 4
+
+=item coretest
+
+Run F<perl> on all core tests (F<t/*> and F<lib/[a-z]*> pragma tests).
+
+(Not available on Win32)
+
+=item test.deparse
+
+Run all the tests through B::Deparse. Not all tests will succeed.
+
+(Not available on Win32)
+
+=item test.taintwarn
+
+Run all tests with the B<-t> command-line switch. Not all tests
+are expected to succeed (until they're specifically fixed, of course).
+
+(Not available on Win32)
+
+=item minitest
+
+Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>,
+F<t/op>, F<t/uni> and F<t/mro> tests.
+
+=item test.valgrind check.valgrind utest.valgrind ucheck.valgrind
+
+(Only in Linux) Run all the tests using the memory leak + naughty
+memory access tool "valgrind". The log files will be named
+F<testname.valgrind>.
+
+=item test.third check.third utest.third ucheck.third
+
+(Only in Tru64) Run all the tests using the memory leak + naughty
+memory access tool "Third Degree". The log files will be named
+F<perl.3log.testname>.
+
+=item test.torture torturetest
+
+Run all the usual tests and some extra tests. As of Perl 5.8.0 the
+only extra tests are Abigail's JAPHs, F<t/japh/abigail.t>.
+
+You can also run the torture test with F<t/harness> by giving
+C<-torture> argument to F<t/harness>.
+
+=item utest ucheck test.utf8 check.utf8
+
+Run all the tests with -Mutf8. Not all tests will succeed.
+
+(Not available on Win32)
+
+=item minitest.utf16 test.utf16
+
+Runs the tests with UTF-16 encoded scripts, encoded with different
+versions of this encoding.
+
+C<make utest.utf16> runs the test suite with a combination of C<-utf8> and
+C<-utf16> arguments to F<t/TEST>.
+
+(Not available on Win32)
+
+=item test_harness
+
+Run the test suite with the F<t/harness> controlling program, instead of
+F<t/TEST>. F<t/harness> is more sophisticated, and uses the
+L<Test::Harness> module, thus using this test target supposes that perl
+mostly works. The main advantage for our purposes is that it prints a
+detailed summary of failed tests at the end. Also, unlike F<t/TEST>, it
+doesn't redirect stderr to stdout.
+
+Note that under Win32 F<t/harness> is always used instead of F<t/TEST>, so
+there is no special "test_harness" target.
+
+Under Win32's "test" target you may use the TEST_SWITCHES and TEST_FILES
+environment variables to control the behaviour of F<t/harness>. This means
+you can say
+
+ nmake test TEST_FILES="op/*.t"
+ nmake test TEST_SWITCHES="-torture" TEST_FILES="op/*.t"
+
+=item Parallel tests
+
+The core distribution can now run its regression tests in parallel on
+Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
+your environment to the number of tests to run in parallel, and run
+C<make test_harness>. On a Bourne-like shell, this can be done as
+
+ TEST_JOBS=3 make test_harness # Run 3 tests in parallel
+
+An environment variable is used, rather than parallel make itself, because
+L<TAP::Harness> needs to be able to schedule individual non-conflicting test
+scripts itself, and there is no standard interface to C<make> utilities to
+interact with their job schedulers.
+
+Note that currently some test scripts may fail when run in parallel (most
+notably C<ext/IO/t/io_dir.t>). If necessary run just the failing scripts
+again sequentially and see if the failures go away.
+=item test-notty test_notty
+
+Sets PERL_SKIP_TTY_TEST to true before running normal test.
+
+=back
+
+=head2 Running tests by hand
+
+You can run part of the test suite by hand by using one the following
+commands from the F<t/> directory :
+
+ ./perl -I../lib TEST list-of-.t-files
+
+or
+
+ ./perl -I../lib harness list-of-.t-files
+
+(if you don't specify test scripts, the whole test suite will be run.)
+
+=head3 Using t/harness for testing
+
+If you use C<harness> for testing you have several command line options
+available to you. The arguments are as follows, and are in the order
+that they must appear if used together.
+
+ harness -v -torture -re=pattern LIST OF FILES TO TEST
+ harness -v -torture -re LIST OF PATTERNS TO MATCH
+
+If C<LIST OF FILES TO TEST> is omitted the file list is obtained from
+the manifest. The file list may include shell wildcards which will be
+expanded out.
+
+=over 4
+
+=item -v
+
+Run the tests under verbose mode so you can see what tests were run,
+and debug output.
+
+=item -torture
+
+Run the torture tests as well as the normal set.
+
+=item -re=PATTERN
+
+Filter the file list so that all the test files run match PATTERN.
+Note that this form is distinct from the B<-re LIST OF PATTERNS> form below
+in that it allows the file list to be provided as well.
+
+=item -re LIST OF PATTERNS
+
+Filter the file list so that all the test files run match
+/(LIST|OF|PATTERNS)/. Note that with this form the patterns
+are joined by '|' and you cannot supply a list of files, instead
+the test files are obtained from the MANIFEST.
+
+=back
+
+You can run an individual test by a command similar to
+
+ ./perl -I../lib patho/to/foo.t
+
+except that the harnesses set up some environment variables that may
+affect the execution of the test :
+
+=over 4
+
+=item PERL_CORE=1
+
+indicates that we're running this test part of the perl core test suite.
+This is useful for modules that have a dual life on CPAN.
+
+=item PERL_DESTRUCT_LEVEL=2
+
+is set to 2 if it isn't set already (see L</PERL_DESTRUCT_LEVEL>)
+
+=item PERL
+
+(used only by F<t/TEST>) if set, overrides the path to the perl executable
+that should be used to run the tests (the default being F<./perl>).
+
+=item PERL_SKIP_TTY_TEST
+
+if set, tells to skip the tests that need a terminal. It's actually set
+automatically by the Makefile, but can also be forced artificially by
+running 'make test_notty'.
+
+=back
+
+=head3 Other environment variables that may influence tests
+
+=over 4
+
+=item PERL_TEST_Net_Ping
+
+Setting this variable runs all the Net::Ping modules tests,
+otherwise some tests that interact with the outside world are skipped.
+See L<perl58delta>.
+
+=item PERL_TEST_NOVREXX
+
+Setting this variable skips the vrexx.t tests for OS2::REXX.
+
+=item PERL_TEST_NUMCONVERTS
+
+This sets a variable in op/numconvert.t.
+
+=back
+
+See also the documentation for the Test and Test::Harness modules,
+for more environment variables that affect testing.
+
+=head2 Common problems when patching Perl source code
+
+Perl source plays by ANSI C89 rules: no C99 (or C++) extensions. In
+some cases we have to take pre-ANSI requirements into consideration.
+You don't care about some particular platform having broken Perl?
+I hear there is still a strong demand for J2EE programmers.
+
+=head2 Perl environment problems
+
+=over 4
+
+=item *
+
+Not compiling with threading
+
+Compiling with threading (-Duseithreads) completely rewrites
+the function prototypes of Perl. You better try your changes
+with that. Related to this is the difference between "Perl_-less"
+and "Perl_-ly" APIs, for example:
+
+ Perl_sv_setiv(aTHX_ ...);
+ sv_setiv(...);
+
+The first one explicitly passes in the context, which is needed for e.g.
+threaded builds. The second one does that implicitly; do not get them
+mixed. If you are not passing in a aTHX_, you will need to do a dTHX
+(or a dVAR) as the first thing in the function.
+
+See L<perlguts/"How multiple interpreters and concurrency are supported">
+for further discussion about context.
+
+=item *
+
+Not compiling with -DDEBUGGING
+
+The DEBUGGING define exposes more code to the compiler,
+therefore more ways for things to go wrong. You should try it.
+
+=item *
+
+Introducing (non-read-only) globals
+
+Do not introduce any modifiable globals, truly global or file static.
+They are bad form and complicate multithreading and other forms of
+concurrency. The right way is to introduce them as new interpreter
+variables, see F<intrpvar.h> (at the very end for binary compatibility).
+
+Introducing read-only (const) globals is okay, as long as you verify
+with e.g. C<nm libperl.a|egrep -v ' [TURtr] '> (if your C<nm> has
+BSD-style output) that the data you added really is read-only.
+(If it is, it shouldn't show up in the output of that command.)
+
+If you want to have static strings, make them constant:
+
+ static const char etc[] = "...";
+
+If you want to have arrays of constant strings, note carefully
+the right combination of C<const>s:
+
+ static const char * const yippee[] =
+ {"hi", "ho", "silver"};
+
+There is a way to completely hide any modifiable globals (they are all
+moved to heap), the compilation setting C<-DPERL_GLOBAL_STRUCT_PRIVATE>.
+It is not normally used, but can be used for testing, read more
+about it in L<perlguts/"Background and PERL_IMPLICIT_CONTEXT">.
+
+=item *
+
+Not exporting your new function
+
+Some platforms (Win32, AIX, VMS, OS/2, to name a few) require any
+function that is part of the public API (the shared Perl library)
+to be explicitly marked as exported. See the discussion about
+F<embed.pl> in L<perlguts>.
+
+=item *
+
+Exporting your new function
+
+The new shiny result of either genuine new functionality or your
+arduous refactoring is now ready and correctly exported. So what
+could possibly go wrong?
+
+Maybe simply that your function did not need to be exported in the
+first place. Perl has a long and not so glorious history of exporting
+functions that it should not have.
+
+If the function is used only inside one source code file, make it
+static. See the discussion about F<embed.pl> in L<perlguts>.
+
+If the function is used across several files, but intended only for
+Perl's internal use (and this should be the common case), do not
+export it to the public API. See the discussion about F<embed.pl>
+in L<perlguts>.
+
+=back
+
+=head2 Portability problems
+
+The following are common causes of compilation and/or execution
+failures, not common to Perl as such. The C FAQ is good bedtime
+reading. Please test your changes with as many C compilers and
+platforms as possible; we will, anyway, and it's nice to save
+oneself from public embarrassment.
+
+If using gcc, you can add the C<-std=c89> option which will hopefully
+catch most of these unportabilities. (However it might also catch
+incompatibilities in your system's header files.)
+
+Use the Configure C<-Dgccansipedantic> flag to enable the gcc
+C<-ansi -pedantic> flags which enforce stricter ANSI rules.
+
+If using the C<gcc -Wall> note that not all the possible warnings
+(like C<-Wunitialized>) are given unless you also compile with C<-O>.
+
+Note that if using gcc, starting from Perl 5.9.5 the Perl core source
+code files (the ones at the top level of the source code distribution,
+but not e.g. the extensions under ext/) are automatically compiled
+with as many as possible of the C<-std=c89>, C<-ansi>, C<-pedantic>,
+and a selection of C<-W> flags (see cflags.SH).
+
+Also study L<perlport> carefully to avoid any bad assumptions
+about the operating system, filesystems, and so forth.
+
+You may once in a while try a "make microperl" to see whether we
+can still compile Perl with just the bare minimum of interfaces.
+(See README.micro.)
+
+Do not assume an operating system indicates a certain compiler.
+
+=over 4
+
+=item *
+
+Casting pointers to integers or casting integers to pointers
+
+ void castaway(U8* p)
+ {
+ IV i = p;
+
+or
+
+ void castaway(U8* p)
+ {
+ IV i = (IV)p;
+
+Both are bad, and broken, and unportable. Use the PTR2IV()
+macro that does it right. (Likewise, there are PTR2UV(), PTR2NV(),
+INT2PTR(), and NUM2PTR().)
+
+=item *
+
+Casting between data function pointers and data pointers
+
+Technically speaking casting between function pointers and data
+pointers is unportable and undefined, but practically speaking
+it seems to work, but you should use the FPTR2DPTR() and DPTR2FPTR()
+macros. Sometimes you can also play games with unions.
+
+=item *
+
+Assuming sizeof(int) == sizeof(long)
+
+There are platforms where longs are 64 bits, and platforms where ints
+are 64 bits, and while we are out to shock you, even platforms where
+shorts are 64 bits. This is all legal according to the C standard.
+(In other words, "long long" is not a portable way to specify 64 bits,
+and "long long" is not even guaranteed to be any wider than "long".)
+
+Instead, use the definitions IV, UV, IVSIZE, I32SIZE, and so forth.
+Avoid things like I32 because they are B<not> guaranteed to be
+I<exactly> 32 bits, they are I<at least> 32 bits, nor are they
+guaranteed to be B<int> or B<long>. If you really explicitly need
+64-bit variables, use I64 and U64, but only if guarded by HAS_QUAD.
+
+=item *
+
+Assuming one can dereference any type of pointer for any type of data
+
+ char *p = ...;
+ long pony = *p; /* BAD */
+
+Many platforms, quite rightly so, will give you a core dump instead
+of a pony if the p happens not be correctly aligned.
+
+=item *
+
+Lvalue casts
+
+ (int)*p = ...; /* BAD */
+
+Simply not portable. Get your lvalue to be of the right type,
+or maybe use temporary variables, or dirty tricks with unions.
+
+=item *
+
+Assume B<anything> about structs (especially the ones you
+don't control, like the ones coming from the system headers)
+
+=over 8
+
+=item *
+
+That a certain field exists in a struct
+
+=item *
+
+That no other fields exist besides the ones you know of
+
+=item *
+
+That a field is of certain signedness, sizeof, or type
+
+=item *
+
+That the fields are in a certain order
+
+=over 8
+
+=item *
+
+While C guarantees the ordering specified in the struct definition,
+between different platforms the definitions might differ
+
+=back
+
+=item *
+
+That the sizeof(struct) or the alignments are the same everywhere
+
+=over 8
+
+=item *
+
+There might be padding bytes between the fields to align the fields -
+the bytes can be anything
+
+=item *
+
+Structs are required to be aligned to the maximum alignment required
+by the fields - which for native types is for usually equivalent to
+sizeof() of the field
+
+=back
+
+=back
+
+=item *
+
+Assuming the character set is ASCIIish
+
+Perl can compile and run under EBCDIC platforms. See L<perlebcdic>.
+This is transparent for the most part, but because the character sets
+differ, you shouldn't use numeric (decimal, octal, nor hex) constants
+to refer to characters. You can safely say 'A', but not 0x41.
+You can safely say '\n', but not \012.
+If a character doesn't have a trivial input form, you can
+create a #define for it in both C<utfebcdic.h> and C<utf8.h>, so that
+it resolves to different values depending on the character set being used.
+(There are three different EBCDIC character sets defined in C<utfebcdic.h>,
+so it might be best to insert the #define three times in that file.)
+
+Also, the range 'A' - 'Z' in ASCII is an unbroken sequence of 26 upper case
+alphabetic characters. That is not true in EBCDIC. Nor for 'a' to 'z'.
+But '0' - '9' is an unbroken range in both systems. Don't assume anything
+about other ranges.
+
+Many of the comments in the existing code ignore the possibility of EBCDIC,
+and may be wrong therefore, even if the code works.
+This is actually a tribute to the successful transparent insertion of being
+able to handle EBCDIC without having to change pre-existing code.
+
+UTF-8 and UTF-EBCDIC are two different encodings used to represent Unicode
+code points as sequences of bytes. Macros
+with the same names (but different definitions)
+in C<utf8.h> and C<utfebcdic.h>
+are used to allow the calling code to think that there is only one such
+encoding.
+This is almost always referred to as C<utf8>, but it means the EBCDIC version
+as well. Again, comments in the code may well be wrong even if the code itself
+is right.
+For example, the concept of C<invariant characters> differs between ASCII and
+EBCDIC.
+On ASCII platforms, only characters that do not have the high-order
+bit set (i.e. whose ordinals are strict ASCII, 0 - 127)
+are invariant, and the documentation and comments in the code
+may assume that,
+often referring to something like, say, C<hibit>.
+The situation differs and is not so simple on EBCDIC machines, but as long as
+the code itself uses the C<NATIVE_IS_INVARIANT()> macro appropriately, it
+works, even if the comments are wrong.
+
+=item *
+
+Assuming the character set is just ASCII
+
+ASCII is a 7 bit encoding, but bytes have 8 bits in them. The 128 extra
+characters have different meanings depending on the locale. Absent a locale,
+currently these extra characters are generally considered to be unassigned,
+and this has presented some problems.
+This is being changed starting in 5.12 so that these characters will
+be considered to be Latin-1 (ISO-8859-1).
+
+=item *
+
+Mixing #define and #ifdef
+
+ #define BURGLE(x) ... \
+ #ifdef BURGLE_OLD_STYLE /* BAD */
+ ... do it the old way ... \
+ #else
+ ... do it the new way ... \
+ #endif
+
+You cannot portably "stack" cpp directives. For example in the above
+you need two separate BURGLE() #defines, one for each #ifdef branch.
+
+=item *
+
+Adding non-comment stuff after #endif or #else
+
+ #ifdef SNOSH
+ ...
+ #else !SNOSH /* BAD */
+ ...
+ #endif SNOSH /* BAD */
+
+The #endif and #else cannot portably have anything non-comment after
+them. If you want to document what is going (which is a good idea
+especially if the branches are long), use (C) comments:
+
+ #ifdef SNOSH
+ ...
+ #else /* !SNOSH */
+ ...
+ #endif /* SNOSH */
+
+The gcc option C<-Wendif-labels> warns about the bad variant
+(by default on starting from Perl 5.9.4).
+
+=item *
+
+Having a comma after the last element of an enum list
+
+ enum color {
+ CERULEAN,
+ CHARTREUSE,
+ CINNABAR, /* BAD */
+ };
+
+is not portable. Leave out the last comma.
+
+Also note that whether enums are implicitly morphable to ints
+varies between compilers, you might need to (int).
+
+=item *
+
+Using //-comments
+
+ // This function bamfoodles the zorklator. /* BAD */
+
+That is C99 or C++. Perl is C89. Using the //-comments is silently
+allowed by many C compilers but cranking up the ANSI C89 strictness
+(which we like to do) causes the compilation to fail.
+
+=item *
+
+Mixing declarations and code
+
+ void zorklator()
+ {
+ int n = 3;
+ set_zorkmids(n); /* BAD */
+ int q = 4;
+
+That is C99 or C++. Some C compilers allow that, but you shouldn't.
+
+The gcc option C<-Wdeclaration-after-statements> scans for such problems
+(by default on starting from Perl 5.9.4).
+
+=item *
+
+Introducing variables inside for()
+
+ for(int i = ...; ...; ...) { /* BAD */
+
+That is C99 or C++. While it would indeed be awfully nice to have that
+also in C89, to limit the scope of the loop variable, alas, we cannot.
+
+=item *
+
+Mixing signed char pointers with unsigned char pointers
+
+ int foo(char *s) { ... }
+ ...
+ unsigned char *t = ...; /* Or U8* t = ... */
+ foo(t); /* BAD */
+
+While this is legal practice, it is certainly dubious, and downright
+fatal in at least one platform: for example VMS cc considers this a
+fatal error. One cause for people often making this mistake is that a
+"naked char" and therefore dereferencing a "naked char pointer" have
+an undefined signedness: it depends on the compiler and the flags of
+the compiler and the underlying platform whether the result is signed
+or unsigned. For this very same reason using a 'char' as an array
+index is bad.
+
+=item *
+
+Macros that have string constants and their arguments as substrings of
+the string constants
+
+ #define FOO(n) printf("number = %d\n", n) /* BAD */
+ FOO(10);
+
+Pre-ANSI semantics for that was equivalent to
+
+ printf("10umber = %d\10");
+
+which is probably not what you were expecting. Unfortunately at least
+one reasonably common and modern C compiler does "real backward
+compatibility" here, in AIX that is what still happens even though the
+rest of the AIX compiler is very happily C89.
+
+=item *
+
+Using printf formats for non-basic C types
+
+ IV i = ...;
+ printf("i = %d\n", i); /* BAD */
+
+While this might by accident work in some platform (where IV happens
+to be an C<int>), in general it cannot. IV might be something larger.
+Even worse the situation is with more specific types (defined by Perl's
+configuration step in F<config.h>):
+
+ Uid_t who = ...;
+ printf("who = %d\n", who); /* BAD */
+
+The problem here is that Uid_t might be not only not C<int>-wide
+but it might also be unsigned, in which case large uids would be
+printed as negative values.
+
+There is no simple solution to this because of printf()'s limited
+intelligence, but for many types the right format is available as
+with either 'f' or '_f' suffix, for example:
+
+ IVdf /* IV in decimal */
+ UVxf /* UV is hexadecimal */
+
+ printf("i = %"IVdf"\n", i); /* The IVdf is a string constant. */
+
+ Uid_t_f /* Uid_t in decimal */
+
+ printf("who = %"Uid_t_f"\n", who);
+
+Or you can try casting to a "wide enough" type:
+
+ printf("i = %"IVdf"\n", (IV)something_very_small_and_signed);
+
+Also remember that the C<%p> format really does require a void pointer:
+
+ U8* p = ...;
+ printf("p = %p\n", (void*)p);
+
+The gcc option C<-Wformat> scans for such problems.
+
+=item *
+
+Blindly using variadic macros
+
+gcc has had them for a while with its own syntax, and C99 brought
+them with a standardized syntax. Don't use the former, and use
+the latter only if the HAS_C99_VARIADIC_MACROS is defined.
+
+=item *
+
+Blindly passing va_list
+
+Not all platforms support passing va_list to further varargs (stdarg)
+functions. The right thing to do is to copy the va_list using the
+Perl_va_copy() if the NEED_VA_COPY is defined.
+
+=item *
+
+Using gcc statement expressions
+
+ val = ({...;...;...}); /* BAD */
+
+While a nice extension, it's not portable. The Perl code does
+admittedly use them if available to gain some extra speed
+(essentially as a funky form of inlining), but you shouldn't.
+
+=item *
+
+Binding together several statements in a macro
+
+Use the macros STMT_START and STMT_END.
+
+ STMT_START {
+ ...
+ } STMT_END
+
+=item *
+
+Testing for operating systems or versions when should be testing for features
+
+ #ifdef __FOONIX__ /* BAD */
+ foo = quux();
+ #endif
+
+Unless you know with 100% certainty that quux() is only ever available
+for the "Foonix" operating system B<and> that is available B<and>
+correctly working for B<all> past, present, B<and> future versions of
+"Foonix", the above is very wrong. This is more correct (though still
+not perfect, because the below is a compile-time check):
+
+ #ifdef HAS_QUUX
+ foo = quux();
+ #endif
+
+How does the HAS_QUUX become defined where it needs to be? Well, if
+Foonix happens to be Unixy enough to be able to run the Configure
+script, and Configure has been taught about detecting and testing
+quux(), the HAS_QUUX will be correctly defined. In other platforms,
+the corresponding configuration step will hopefully do the same.
+
+In a pinch, if you cannot wait for Configure to be educated,
+or if you have a good hunch of where quux() might be available,
+you can temporarily try the following:
+
+ #if (defined(__FOONIX__) || defined(__BARNIX__))
+ # define HAS_QUUX
+ #endif
+
+ ...
+
+ #ifdef HAS_QUUX
+ foo = quux();
+ #endif
+
+But in any case, try to keep the features and operating systems separate.
+
+=back
+
+=head2 Problematic System Interfaces
+
+=over 4
+
+=item *
+
+malloc(0), realloc(0), calloc(0, 0) are non-portable. To be portable
+allocate at least one byte. (In general you should rarely need to
+work at this low level, but instead use the various malloc wrappers.)
+
+=item *
+
+snprintf() - the return type is unportable. Use my_snprintf() instead.
+
+=back
+
+=head2 Security problems
+
+Last but not least, here are various tips for safer coding.
+
+=over 4
+
+=item *
+
+Do not use gets()
+
+Or we will publicly ridicule you. Seriously.
+
+=item *
+
+Do not use strcpy() or strcat() or strncpy() or strncat()
+
+Use my_strlcpy() and my_strlcat() instead: they either use the native
+implementation, or Perl's own implementation (borrowed from the public
+domain implementation of INN).
+
+=item *
+
+Do not use sprintf() or vsprintf()
+
+If you really want just plain byte strings, use my_snprintf()
+and my_vsnprintf() instead, which will try to use snprintf() and
+vsnprintf() if those safer APIs are available. If you want something
+fancier than a plain byte string, use SVs and Perl_sv_catpvf().
+
+=back
+
+=head1 EXTERNAL TOOLS FOR DEBUGGING PERL
+
+Sometimes it helps to use external tools while debugging and
+testing Perl. This section tries to guide you through using
+some common testing and debugging tools with Perl. This is
+meant as a guide to interfacing these tools with Perl, not
+as any kind of guide to the use of the tools themselves.
+
+B<NOTE 1>: Running under memory debuggers such as Purify, valgrind, or
+Third Degree greatly slows down the execution: seconds become minutes,
+minutes become hours. For example as of Perl 5.8.1, the
+ext/Encode/t/Unicode.t takes extraordinarily long to complete under
+e.g. Purify, Third Degree, and valgrind. Under valgrind it takes more
+than six hours, even on a snappy computer. The said test must be
+doing something that is quite unfriendly for memory debuggers. If you
+don't feel like waiting, that you can simply kill away the perl
+process.
+
+B<NOTE 2>: To minimize the number of memory leak false alarms (see
+L</PERL_DESTRUCT_LEVEL> for more information), you have to set the
+environment variable PERL_DESTRUCT_LEVEL to 2.
+
+For csh-like shells:
+
+ setenv PERL_DESTRUCT_LEVEL 2
+
+For Bourne-type shells:
+
+ PERL_DESTRUCT_LEVEL=2
+ export PERL_DESTRUCT_LEVEL
+
+In Unixy environments you can also use the C<env> command:
+
+ env PERL_DESTRUCT_LEVEL=2 valgrind ./perl -Ilib ...
+
+B<NOTE 3>: There are known memory leaks when there are compile-time
+errors within eval or require, seeing C<S_doeval> in the call stack
+is a good sign of these. Fixing these leaks is non-trivial,
+unfortunately, but they must be fixed eventually.
+
+B<NOTE 4>: L<DynaLoader> will not clean up after itself completely
+unless Perl is built with the Configure option
+C<-Accflags=-DDL_UNLOAD_ALL_AT_EXIT>.
+
+=head2 Rational Software's Purify
+
+Purify is a commercial tool that is helpful in identifying
+memory overruns, wild pointers, memory leaks and other such
+badness. Perl must be compiled in a specific way for
+optimal testing with Purify. Purify is available under
+Windows NT, Solaris, HP-UX, SGI, and Siemens Unix.
+
+=head2 Purify on Unix
+
+On Unix, Purify creates a new Perl binary. To get the most
+benefit out of Purify, you should create the perl to Purify
+using:
+
+ sh Configure -Accflags=-DPURIFY -Doptimize='-g' \
+ -Uusemymalloc -Dusemultiplicity
+
+where these arguments mean:
+
+=over 4
+
+=item -Accflags=-DPURIFY
+
+Disables Perl's arena memory allocation functions, as well as
+forcing use of memory allocation functions derived from the
+system malloc.
+
+=item -Doptimize='-g'
+
+Adds debugging information so that you see the exact source
+statements where the problem occurs. Without this flag, all
+you will see is the source filename of where the error occurred.
+
+=item -Uusemymalloc
+
+Disable Perl's malloc so that Purify can more closely monitor
+allocations and leaks. Using Perl's malloc will make Purify
+report most leaks in the "potential" leaks category.
+
+=item -Dusemultiplicity
+
+Enabling the multiplicity option allows perl to clean up
+thoroughly when the interpreter shuts down, which reduces the
+number of bogus leak reports from Purify.
+
+=back
+
+Once you've compiled a perl suitable for Purify'ing, then you
+can just:
+
+ make pureperl
+
+which creates a binary named 'pureperl' that has been Purify'ed.
+This binary is used in place of the standard 'perl' binary
+when you want to debug Perl memory problems.
+
+As an example, to show any memory leaks produced during the
+standard Perl testset you would create and run the Purify'ed
+perl as:
+
+ make pureperl
+ cd t
+ ../pureperl -I../lib harness
+
+which would run Perl on test.pl and report any memory problems.
+
+Purify outputs messages in "Viewer" windows by default. If
+you don't have a windowing environment or if you simply
+want the Purify output to unobtrusively go to a log file
+instead of to the interactive window, use these following
+options to output to the log file "perl.log":
+
+ setenv PURIFYOPTIONS "-chain-length=25 -windows=no \
+ -log-file=perl.log -append-logfile=yes"
+
+If you plan to use the "Viewer" windows, then you only need this option:
+
+ setenv PURIFYOPTIONS "-chain-length=25"
+
+In Bourne-type shells:
+
+ PURIFYOPTIONS="..."
+ export PURIFYOPTIONS
+
+or if you have the "env" utility:
+
+ env PURIFYOPTIONS="..." ../pureperl ...
+
+=head2 Purify on NT
+
+Purify on Windows NT instruments the Perl binary 'perl.exe'
+on the fly. There are several options in the makefile you
+should change to get the most use out of Purify:
+
+=over 4
+
+=item DEFINES
+
+You should add -DPURIFY to the DEFINES line so the DEFINES
+line looks something like:
+
+ DEFINES = -DWIN32 -D_CONSOLE -DNO_STRICT $(CRYPT_FLAG) -DPURIFY=1
+
+to disable Perl's arena memory allocation functions, as
+well as to force use of memory allocation functions derived
+from the system malloc.
+
+=item USE_MULTI = define
+
+Enabling the multiplicity option allows perl to clean up
+thoroughly when the interpreter shuts down, which reduces the
+number of bogus leak reports from Purify.
+
+=item #PERL_MALLOC = define
+
+Disable Perl's malloc so that Purify can more closely monitor
+allocations and leaks. Using Perl's malloc will make Purify
+report most leaks in the "potential" leaks category.
+
+=item CFG = Debug
+
+Adds debugging information so that you see the exact source
+statements where the problem occurs. Without this flag, all
+you will see is the source filename of where the error occurred.
+
+=back
+
+As an example, to show any memory leaks produced during the
+standard Perl testset you would create and run Purify as:
+
+ cd win32
+ make
+ cd ../t
+ purify ../perl -I../lib harness
+
+which would instrument Perl in memory, run Perl on test.pl,
+then finally report any memory problems.
+
+=head2 valgrind
+
+The excellent valgrind tool can be used to find out both memory leaks
+and illegal memory accesses. As of version 3.3.0, Valgrind only
+supports Linux on x86, x86-64 and PowerPC. The special "test.valgrind"
+target can be used to run the tests under valgrind. Found errors
+and memory leaks are logged in files named F<testfile.valgrind>.
+
+Valgrind also provides a cachegrind tool, invoked on perl as:
+
+ VG_OPTS=--tool=cachegrind make test.valgrind
+
+As system libraries (most notably glibc) are also triggering errors,
+valgrind allows to suppress such errors using suppression files. The
+default suppression file that comes with valgrind already catches a lot
+of them. Some additional suppressions are defined in F<t/perl.supp>.
+
+To get valgrind and for more information see
+
+ http://developer.kde.org/~sewardj/
+
+=head2 Compaq's/Digital's/HP's Third Degree
+
+Third Degree is a tool for memory leak detection and memory access checks.
+It is one of the many tools in the ATOM toolkit. The toolkit is only
+available on Tru64 (formerly known as Digital UNIX formerly known as
+DEC OSF/1).
+
+When building Perl, you must first run Configure with -Doptimize=-g
+and -Uusemymalloc flags, after that you can use the make targets
+"perl.third" and "test.third". (What is required is that Perl must be
+compiled using the C<-g> flag, you may need to re-Configure.)
+
+The short story is that with "atom" you can instrument the Perl
+executable to create a new executable called F<perl.third>. When the
+instrumented executable is run, it creates a log of dubious memory
+traffic in file called F<perl.3log>. See the manual pages of atom and
+third for more information. The most extensive Third Degree
+documentation is available in the Compaq "Tru64 UNIX Programmer's
+Guide", chapter "Debugging Programs with Third Degree".
+
+The "test.third" leaves a lot of files named F<foo_bar.3log> in the t/
+subdirectory. There is a problem with these files: Third Degree is so
+effective that it finds problems also in the system libraries.
+Therefore you should used the Porting/thirdclean script to cleanup
+the F<*.3log> files.
+
+There are also leaks that for given certain definition of a leak,
+aren't. See L</PERL_DESTRUCT_LEVEL> for more information.
+
+=head2 PERL_DESTRUCT_LEVEL
+
+If you want to run any of the tests yourself manually using e.g.
+valgrind, or the pureperl or perl.third executables, please note that
+by default perl B<does not> explicitly cleanup all the memory it has
+allocated (such as global memory arenas) but instead lets the exit()
+of the whole program "take care" of such allocations, also known as
+"global destruction of objects".
+
+There is a way to tell perl to do complete cleanup: set the
+environment variable PERL_DESTRUCT_LEVEL to a non-zero value.
+The t/TEST wrapper does set this to 2, and this is what you
+need to do too, if you don't want to see the "global leaks":
+For example, for "third-degreed" Perl:
+
+ env PERL_DESTRUCT_LEVEL=2 ./perl.third -Ilib t/foo/bar.t
+
+(Note: the mod_perl apache module uses also this environment variable
+for its own purposes and extended its semantics. Refer to the mod_perl
+documentation for more information. Also, spawned threads do the
+equivalent of setting this variable to the value 1.)
+
+If, at the end of a run you get the message I<N scalars leaked>, you can
+recompile with C<-DDEBUG_LEAKING_SCALARS>, which will cause the addresses
+of all those leaked SVs to be dumped along with details as to where each
+SV was originally allocated. This information is also displayed by
+Devel::Peek. Note that the extra details recorded with each SV increases
+memory usage, so it shouldn't be used in production environments. It also
+converts C<new_SV()> from a macro into a real function, so you can use
+your favourite debugger to discover where those pesky SVs were allocated.
+
+If you see that you're leaking memory at runtime, but neither valgrind
+nor C<-DDEBUG_LEAKING_SCALARS> will find anything, you're probably
+leaking SVs that are still reachable and will be properly cleaned up
+during destruction of the interpreter. In such cases, using the C<-Dm>
+switch can point you to the source of the leak. If the executable was
+built with C<-DDEBUG_LEAKING_SCALARS>, C<-Dm> will output SV allocations
+in addition to memory allocations. Each SV allocation has a distinct
+serial number that will be written on creation and destruction of the SV.
+So if you're executing the leaking code in a loop, you need to look for
+SVs that are created, but never destroyed between each cycle. If such an
+SV is found, set a conditional breakpoint within C<new_SV()> and make it
+break only when C<PL_sv_serial> is equal to the serial number of the
+leaking SV. Then you will catch the interpreter in exactly the state
+where the leaking SV is allocated, which is sufficient in many cases to
+find the source of the leak.
+
+As C<-Dm> is using the PerlIO layer for output, it will by itself
+allocate quite a bunch of SVs, which are hidden to avoid recursion.
+You can bypass the PerlIO layer if you use the SV logging provided
+by C<-DPERL_MEM_LOG> instead.
+
+=head2 PERL_MEM_LOG
+
+If compiled with C<-DPERL_MEM_LOG>, both memory and SV allocations go
+through logging functions, which is handy for breakpoint setting.
+
+Unless C<-DPERL_MEM_LOG_NOIMPL> is also compiled, the logging
+functions read $ENV{PERL_MEM_LOG} to determine whether to log the
+event, and if so how:
+
+ $ENV{PERL_MEM_LOG} =~ /m/ Log all memory ops
+ $ENV{PERL_MEM_LOG} =~ /s/ Log all SV ops
+ $ENV{PERL_MEM_LOG} =~ /t/ include timestamp in Log
+ $ENV{PERL_MEM_LOG} =~ /^(\d+)/ write to FD given (default is 2)
+
+Memory logging is somewhat similar to C<-Dm> but is independent of
+C<-DDEBUGGING>, and at a higher level; all uses of Newx(), Renew(),
+and Safefree() are logged with the caller's source code file and line
+number (and C function name, if supported by the C compiler). In
+contrast, C<-Dm> is directly at the point of C<malloc()>. SV logging
+is similar.
+
+Since the logging doesn't use PerlIO, all SV allocations are logged
+and no extra SV allocations are introduced by enabling the logging.
+If compiled with C<-DDEBUG_LEAKING_SCALARS>, the serial number for
+each SV allocation is also logged.
+
+=head2 Profiling
+
+Depending on your platform there are various of profiling Perl.
+
+There are two commonly used techniques of profiling executables:
+I<statistical time-sampling> and I<basic-block counting>.
+
+The first method takes periodically samples of the CPU program
+counter, and since the program counter can be correlated with the code
+generated for functions, we get a statistical view of in which
+functions the program is spending its time. The caveats are that very
+small/fast functions have lower probability of showing up in the
+profile, and that periodically interrupting the program (this is
+usually done rather frequently, in the scale of milliseconds) imposes
+an additional overhead that may skew the results. The first problem
+can be alleviated by running the code for longer (in general this is a
+good idea for profiling), the second problem is usually kept in guard
+by the profiling tools themselves.
+
+The second method divides up the generated code into I<basic blocks>.
+Basic blocks are sections of code that are entered only in the
+beginning and exited only at the end. For example, a conditional jump
+starts a basic block. Basic block profiling usually works by
+I<instrumenting> the code by adding I<enter basic block #nnnn>
+book-keeping code to the generated code. During the execution of the
+code the basic block counters are then updated appropriately. The
+caveat is that the added extra code can skew the results: again, the
+profiling tools usually try to factor their own effects out of the
+results.
+
+=head2 Gprof Profiling
+
+gprof is a profiling tool available in many Unix platforms,
+it uses F<statistical time-sampling>.
+
+You can build a profiled version of perl called "perl.gprof" by
+invoking the make target "perl.gprof" (What is required is that Perl
+must be compiled using the C<-pg> flag, you may need to re-Configure).
+Running the profiled version of Perl will create an output file called
+F<gmon.out> is created which contains the profiling data collected
+during the execution.
+
+The gprof tool can then display the collected data in various ways.
+Usually gprof understands the following options:
+
+=over 4
+
+=item -a
+
+Suppress statically defined functions from the profile.
+
+=item -b
+
+Suppress the verbose descriptions in the profile.
+
+=item -e routine
+
+Exclude the given routine and its descendants from the profile.
+
+=item -f routine
+
+Display only the given routine and its descendants in the profile.
+
+=item -s
+
+Generate a summary file called F<gmon.sum> which then may be given
+to subsequent gprof runs to accumulate data over several runs.
+
+=item -z
+
+Display routines that have zero usage.
+
+=back
+
+For more detailed explanation of the available commands and output
+formats, see your own local documentation of gprof.
+
+quick hint:
+
+ $ sh Configure -des -Dusedevel -Doptimize='-pg' && make perl.gprof
+ $ ./perl.gprof someprog # creates gmon.out in current directory
+ $ gprof ./perl.gprof > out
+ $ view out
+
+=head2 GCC gcov Profiling
+
+Starting from GCC 3.0 I<basic block profiling> is officially available
+for the GNU CC.
+
+You can build a profiled version of perl called F<perl.gcov> by
+invoking the make target "perl.gcov" (what is required that Perl must
+be compiled using gcc with the flags C<-fprofile-arcs
+-ftest-coverage>, you may need to re-Configure).
+
+Running the profiled version of Perl will cause profile output to be
+generated. For each source file an accompanying ".da" file will be
+created.
+
+To display the results you use the "gcov" utility (which should
+be installed if you have gcc 3.0 or newer installed). F<gcov> is
+run on source code files, like this
+
+ gcov sv.c
+
+which will cause F<sv.c.gcov> to be created. The F<.gcov> files
+contain the source code annotated with relative frequencies of
+execution indicated by "#" markers.
+
+Useful options of F<gcov> include C<-b> which will summarise the
+basic block, branch, and function call coverage, and C<-c> which
+instead of relative frequencies will use the actual counts. For
+more information on the use of F<gcov> and basic block profiling
+with gcc, see the latest GNU CC manual, as of GCC 3.0 see
+
+ http://gcc.gnu.org/onlinedocs/gcc-3.0/gcc.html
+
+and its section titled "8. gcov: a Test Coverage Program"
+
+ http://gcc.gnu.org/onlinedocs/gcc-3.0/gcc_8.html#SEC132
+
+quick hint:
+
+ $ sh Configure -des -Doptimize='-g' -Accflags='-fprofile-arcs -ftest-coverage' \
+ -Aldflags='-fprofile-arcs -ftest-coverage' && make perl.gcov
+ $ rm -f regexec.c.gcov regexec.gcda
+ $ ./perl.gcov
+ $ gcov regexec.c
+ $ view regexec.c.gcov
+
+=head2 Pixie Profiling
+
+Pixie is a profiling tool available on IRIX and Tru64 (aka Digital
+UNIX aka DEC OSF/1) platforms. Pixie does its profiling using
+I<basic-block counting>.
+
+You can build a profiled version of perl called F<perl.pixie> by
+invoking the make target "perl.pixie" (what is required is that Perl
+must be compiled using the C<-g> flag, you may need to re-Configure).
+
+In Tru64 a file called F<perl.Addrs> will also be silently created,
+this file contains the addresses of the basic blocks. Running the
+profiled version of Perl will create a new file called "perl.Counts"
+which contains the counts for the basic block for that particular
+program execution.
+
+To display the results you use the F<prof> utility. The exact
+incantation depends on your operating system, "prof perl.Counts" in
+IRIX, and "prof -pixie -all -L. perl" in Tru64.
+
+In IRIX the following prof options are available:
+
+=over 4
+
+=item -h
+
+Reports the most heavily used lines in descending order of use.
+Useful for finding the hotspot lines.
+
+=item -l
+
+Groups lines by procedure, with procedures sorted in descending order of use.
+Within a procedure, lines are listed in source order.
+Useful for finding the hotspots of procedures.
+
+=back
+
+In Tru64 the following options are available:
+
+=over 4
+
+=item -p[rocedures]
+
+Procedures sorted in descending order by the number of cycles executed
+in each procedure. Useful for finding the hotspot procedures.
+(This is the default option.)
+
+=item -h[eavy]
+
+Lines sorted in descending order by the number of cycles executed in
+each line. Useful for finding the hotspot lines.
+
+=item -i[nvocations]
+
+The called procedures are sorted in descending order by number of calls
+made to the procedures. Useful for finding the most used procedures.
+
+=item -l[ines]
+
+Grouped by procedure, sorted by cycles executed per procedure.
+Useful for finding the hotspots of procedures.
+
+=item -testcoverage
+
+The compiler emitted code for these lines, but the code was unexecuted.
+
+=item -z[ero]
+
+Unexecuted procedures.
+
+=back
+
+For further information, see your system's manual pages for pixie and prof.
+
+=head2 Miscellaneous tricks
+
+=over 4
+
+=item *
+
+Those debugging perl with the DDD frontend over gdb may find the
+following useful:
+
+You can extend the data conversion shortcuts menu, so for example you
+can display an SV's IV value with one click, without doing any typing.
+To do that simply edit ~/.ddd/init file and add after:
+
+ ! Display shortcuts.
+ Ddd*gdbDisplayShortcuts: \
+ /t () // Convert to Bin\n\
+ /d () // Convert to Dec\n\
+ /x () // Convert to Hex\n\
+ /o () // Convert to Oct(\n\
+
+the following two lines:
+
+ ((XPV*) (())->sv_any )->xpv_pv // 2pvx\n\
+ ((XPVIV*) (())->sv_any )->xiv_iv // 2ivx
+
+so now you can do ivx and pvx lookups or you can plug there the
+sv_peek "conversion":
+
+ Perl_sv_peek(my_perl, (SV*)()) // sv_peek
+
+(The my_perl is for threaded builds.)
+Just remember that every line, but the last one, should end with \n\
+
+Alternatively edit the init file interactively via:
+3rd mouse button -> New Display -> Edit Menu
+
+Note: you can define up to 20 conversion shortcuts in the gdb
+section.
+
+=item *
+
+If you see in a debugger a memory area mysteriously full of 0xABABABAB
+or 0xEFEFEFEF, you may be seeing the effect of the Poison() macros,
+see L<perlclib>.
+
+=item *
+
+Under ithreads the optree is read only. If you want to enforce this, to check
+for write accesses from buggy code, compile with C<-DPL_OP_SLAB_ALLOC> to
+enable the OP slab allocator and C<-DPERL_DEBUG_READONLY_OPS> to enable code
+that allocates op memory via C<mmap>, and sets it read-only at run time.
+Any write access to an op results in a C<SIGBUS> and abort.
+
+This code is intended for development only, and may not be portable even to
+all Unix variants. Also, it is an 80% solution, in that it isn't able to make
+all ops read only. Specifically it
+
+=over
+
+=item 1
+
+Only sets read-only on all slabs of ops at C<CHECK> time, hence ops allocated
+later via C<require> or C<eval> will be re-write
+
+=item 2
+
+Turns an entire slab of ops read-write if the refcount of any op in the slab
+needs to be decreased.
+
+=item 3
+
+Turns an entire slab of ops read-write if any op from the slab is freed.
+
+=back
+
+It's not possible to turn the slabs to read-only after an action requiring
+read-write access, as either can happen during op tree building time, so
+there may still be legitimate write access.
+
+However, as an 80% solution it is still effective, as currently it catches
+a write access during the generation of F<Config.pm>, which means that we
+can't yet build F<perl> with this enabled.
+
+=back
+
+
+=head1 CONCLUSION
+
+We've had a brief look around the Perl source, how to maintain quality
+of the source code, an overview of the stages F<perl> goes through
+when it's running your code, how to use debuggers to poke at the Perl
+guts, and finally how to analyse the execution of Perl. We took a very
+simple problem and demonstrated how to solve it fully - with
+documentation, regression tests, and finally a patch for submission to
+p5p. Finally, we talked about how to use external tools to debug and
+test Perl.
+
+I'd now suggest you read over those references again, and then, as soon
+as possible, get your hands dirty. The best way to learn is by doing,
+so:
+
+=over 3
+
+=item *
+
+Subscribe to perl5-porters, follow the patches and try and understand
+them; don't be afraid to ask if there's a portion you're not clear on -
+who knows, you may unearth a bug in the patch...
+
+=item *
+
+Keep up to date with the bleeding edge Perl distributions and get
+familiar with the changes. Try and get an idea of what areas people are
+working on and the changes they're making.
+
+=item *
+
+Do read the README associated with your operating system, e.g. README.aix
+on the IBM AIX OS. Don't hesitate to supply patches to that README if
+you find anything missing or changed over a new OS release.
+
+=item *
+
+Find an area of Perl that seems interesting to you, and see if you can
+work out how it works. Scan through the source, and step over it in the
+debugger. Play, poke, investigate, fiddle! You'll probably get to
+understand not just your chosen area but a much wider range of F<perl>'s
+activity as well, and probably sooner than you'd think.
+
+=back
+
+=over 3
+
+=item I<The Road goes ever on and on, down from the door where it began.>
+
+=back
+
+If you can do these things, you've started on the long road to Perl porting.
+Thanks for wanting to help make Perl better - and happy hacking!
+
+=head2 Metaphoric Quotations
+
+If you recognized the quote about the Road above, you're in luck.
+
+Most software projects begin each file with a literal description of each
+file's purpose. Perl instead begins each with a literary allusion to that
+file's purpose.
+
+Like chapters in many books, all top-level Perl source files (along with a
+few others here and there) begin with an epigramic inscription that alludes,
+indirectly and metaphorically, to the material you're about to read.
+
+Quotations are taken from writings of J.R.R Tolkien pertaining to his
+Legendarium, almost always from I<The Lord of the Rings>. Chapters and
+page numbers are given using the following editions:
+
+=over 4
+
+=item *
+
+I<The Hobbit>, by J.R.R. Tolkien. The hardcover, 70th-anniversary
+edition of 2007 was used, published in the UK by Harper Collins Publishers
+and in the US by the Houghton Mifflin Company.
+
+=item *
+
+I<The Lord of the Rings>, by J.R.R. Tolkien. The hardcover,
+50th-anniversary edition of 2004 was used, published in the UK by Harper
+Collins Publishers and in the US by the Houghton Mifflin Company.
+
+=item *
+
+I<The Lays of Beleriand>, by J.R.R. Tolkien and published posthumously by his
+son and literary executor, C.J.R. Tolkien, being the 3rd of the 12 volumes
+in Christopher's mammoth I<History of Middle Earth>. Page numbers derive
+from the hardcover edition, first published in 1983 by George Allen &
+Unwin; no page numbers changed for the special 3-volume omnibus edition of
+2002 or the various trade-paper editions, all again now by Harper Collins
+or Houghton Mifflin.
+
+=back
+
+Other JRRT books fair game for quotes would thus include I<The Adventures of
+Tom Bombadil>, I<The Silmarillion>, I<Unfinished Tales>, and I<The Tale of
+the Children of Hurin>, all but the first posthumously assembled by CJRT.
+But I<The Lord of the Rings> itself is perfectly fine and probably best to
+quote from, provided you can find a suitable quote there.
+
+So if you were to supply a new, complete, top-level source file to add to
+Perl, you should conform to this peculiar practice by yourself selecting an
+appropriate quotation from Tolkien, retaining the original spelling and
+punctuation and using the same format the rest of the quotes are in.
+Indirect and oblique is just fine; remember, it's a metaphor, so being meta
+is, after all, what it's for.
+
+=head1 AUTHOR
+
+This document was written by Nathan Torkington, and is maintained by
+the perl5-porters mailing list.
+
+=head1 SEE ALSO
+
+L<perlrepository>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlhaiku.pod b/Master/tlpkg/tlperl/lib/pods/perlhaiku.pod
new file mode 100644
index 00000000000..c4b6ab79ef3
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlhaiku.pod
@@ -0,0 +1,64 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.haiku - Perl version 5.10+ on Haiku
+
+=head1 DESCRIPTION
+
+This file contains instructions how to build Perl for Haiku and lists
+known problems.
+
+=head1 BUILD AND INSTALL
+
+The build procedure is completely standard:
+
+ ./Configure -de
+ make
+ make install
+
+Make perl executable and create a symlink for libperl:
+
+ chmod a+x /boot/common/bin/perl
+ cd /boot/common/lib; ln -s perl5/5.12.3/BePC-haiku/CORE/libperl.so .
+
+Replace C<5.12.3> with your respective version of Perl.
+
+=head1 KNOWN PROBLEMS
+
+The following problems are encountered with Haiku revision 28311:
+
+=over 4
+
+=item *
+
+Perl cannot be compiled with threading support ATM.
+
+=item *
+
+The C<ext/Socket/t/socketpair.t> test fails. More precisely: the subtests
+using datagram sockets fail. Unix datagram sockets aren't implemented in
+Haiku yet.
+
+=item *
+
+A subtest of the C<ext/Sys/Syslog/t/syslog.t> test fails. This is due to Haiku
+not implementing C</dev/log> support yet.
+
+=item *
+
+The tests C<lib/Net/Ping/t/450_service.t> and C<lib/Net/Ping/t/510_ping_udp.t>
+fail. This is due to bugs in Haiku's network stack implementation.
+
+=back
+
+=head1 CONTACT
+
+For Haiku specific problems contact the HaikuPorts developers:
+http://ports.haiku-files.org/
+
+The initial Haiku port was done by Ingo Weinhold <ingo_weinhold@gmx.de>.
+
+Last update: 2008-10-29
diff --git a/Master/tlpkg/tlperl/lib/pods/perlhist.pod b/Master/tlpkg/tlperl/lib/pods/perlhist.pod
new file mode 100644
index 00000000000..43ac8e91630
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlhist.pod
@@ -0,0 +1,886 @@
+=head1 NAME
+
+perlhist - the Perl history records
+
+=head1 DESCRIPTION
+
+This document aims to record the Perl source code releases.
+
+=head1 INTRODUCTION
+
+Perl history in brief, by Larry Wall:
+
+ Perl 0 introduced Perl to my officemates.
+ Perl 1 introduced Perl to the world, and changed /\(...\|...\)/ to
+ /(...|...)/. \(Dan Faigin still hasn't forgiven me. :-\)
+ Perl 2 introduced Henry Spencer's regular expression package.
+ Perl 3 introduced the ability to handle binary data (embedded nulls).
+ Perl 4 introduced the first Camel book. Really. We mostly just
+ switched version numbers so the book could refer to 4.000.
+ Perl 5 introduced everything else, including the ability to
+ introduce everything else.
+
+=head1 THE KEEPERS OF THE PUMPKIN
+
+Larry Wall, Andy Dougherty, Tom Christiansen, Charles Bailey, Nick
+Ing-Simmons, Chip Salzenberg, Tim Bunce, Malcolm Beattie, Gurusamy
+Sarathy, Graham Barr, Jarkko Hietaniemi, Hugo van der Sanden,
+Michael Schwern, Rafael Garcia-Suarez, Nicholas Clark, Richard Clamp,
+Leon Brocard, Dave Mitchell, Jesse Vincent, Ricardo Signes, Steve Hay.
+
+=head2 PUMPKIN?
+
+[from Porting/pumpkin.pod in the Perl source code distribution]
+
+Chip Salzenberg gets credit for that, with a nod to his cow orker,
+David Croy. We had passed around various names (baton, token, hot
+potato) but none caught on. Then, Chip asked:
+
+[begin quote]
+
+ Who has the patch pumpkin?
+
+To explain: David Croy once told me once that at a previous job,
+there was one tape drive and multiple systems that used it for backups.
+But instead of some high-tech exclusion software, they used a low-tech
+method to prevent multiple simultaneous backups: a stuffed pumpkin.
+No one was allowed to make backups unless they had the "backup pumpkin".
+
+[end quote]
+
+The name has stuck. The holder of the pumpkin is sometimes called
+the pumpking (keeping the source afloat?) or the pumpkineer (pulling
+the strings?).
+
+=head1 THE RECORDS
+
+ Pump- Release Date Notes
+ king (by no means
+ comprehensive,
+ see Changes*
+ for details)
+ ======================================================================
+
+ Larry 0 Classified. Don't ask.
+
+ Larry 1.000 1987-Dec-18
+
+ 1.001..10 1988-Jan-30
+ 1.011..14 1988-Feb-02
+ Schwern 1.0.15 2002-Dec-18 Modernization
+ Richard 1.0.16 2003-Dec-18
+
+ Larry 2.000 1988-Jun-05
+
+ 2.001 1988-Jun-28
+
+ Larry 3.000 1989-Oct-18
+
+ 3.001 1989-Oct-26
+ 3.002..4 1989-Nov-11
+ 3.005 1989-Nov-18
+ 3.006..8 1989-Dec-22
+ 3.009..13 1990-Mar-02
+ 3.014 1990-Mar-13
+ 3.015 1990-Mar-14
+ 3.016..18 1990-Mar-28
+ 3.019..27 1990-Aug-10 User subs.
+ 3.028 1990-Aug-14
+ 3.029..36 1990-Oct-17
+ 3.037 1990-Oct-20
+ 3.040 1990-Nov-10
+ 3.041 1990-Nov-13
+ 3.042..43 1991-Jan-??
+ 3.044 1991-Jan-12
+
+ Larry 4.000 1991-Mar-21
+
+ 4.001..3 1991-Apr-12
+ 4.004..9 1991-Jun-07
+ 4.010 1991-Jun-10
+ 4.011..18 1991-Nov-05
+ 4.019 1991-Nov-11 Stable.
+ 4.020..33 1992-Jun-08
+ 4.034 1992-Jun-11
+ 4.035 1992-Jun-23
+ Larry 4.036 1993-Feb-05 Very stable.
+
+ 5.000alpha1 1993-Jul-31
+ 5.000alpha2 1993-Aug-16
+ 5.000alpha3 1993-Oct-10
+ 5.000alpha4 1993-???-??
+ 5.000alpha5 1993-???-??
+ 5.000alpha6 1994-Mar-18
+ 5.000alpha7 1994-Mar-25
+ Andy 5.000alpha8 1994-Apr-04
+ Larry 5.000alpha9 1994-May-05 ext appears.
+ 5.000alpha10 1994-Jun-11
+ 5.000alpha11 1994-Jul-01
+ Andy 5.000a11a 1994-Jul-07 To fit 14.
+ 5.000a11b 1994-Jul-14
+ 5.000a11c 1994-Jul-19
+ 5.000a11d 1994-Jul-22
+ Larry 5.000alpha12 1994-Aug-04
+ Andy 5.000a12a 1994-Aug-08
+ 5.000a12b 1994-Aug-15
+ 5.000a12c 1994-Aug-22
+ 5.000a12d 1994-Aug-22
+ 5.000a12e 1994-Aug-22
+ 5.000a12f 1994-Aug-24
+ 5.000a12g 1994-Aug-24
+ 5.000a12h 1994-Aug-24
+ Larry 5.000beta1 1994-Aug-30
+ Andy 5.000b1a 1994-Sep-06
+ Larry 5.000beta2 1994-Sep-14 Core slushified.
+ Andy 5.000b2a 1994-Sep-14
+ 5.000b2b 1994-Sep-17
+ 5.000b2c 1994-Sep-17
+ Larry 5.000beta3 1994-Sep-??
+ Andy 5.000b3a 1994-Sep-18
+ 5.000b3b 1994-Sep-22
+ 5.000b3c 1994-Sep-23
+ 5.000b3d 1994-Sep-27
+ 5.000b3e 1994-Sep-28
+ 5.000b3f 1994-Sep-30
+ 5.000b3g 1994-Oct-04
+ Andy 5.000b3h 1994-Oct-07
+ Larry? 5.000gamma 1994-Oct-13?
+
+ Larry 5.000 1994-Oct-17
+
+ Andy 5.000a 1994-Dec-19
+ 5.000b 1995-Jan-18
+ 5.000c 1995-Jan-18
+ 5.000d 1995-Jan-18
+ 5.000e 1995-Jan-18
+ 5.000f 1995-Jan-18
+ 5.000g 1995-Jan-18
+ 5.000h 1995-Jan-18
+ 5.000i 1995-Jan-26
+ 5.000j 1995-Feb-07
+ 5.000k 1995-Feb-11
+ 5.000l 1995-Feb-21
+ 5.000m 1995-Feb-28
+ 5.000n 1995-Mar-07
+ 5.000o 1995-Mar-13?
+
+ Larry 5.001 1995-Mar-13
+
+ Andy 5.001a 1995-Mar-15
+ 5.001b 1995-Mar-31
+ 5.001c 1995-Apr-07
+ 5.001d 1995-Apr-14
+ 5.001e 1995-Apr-18 Stable.
+ 5.001f 1995-May-31
+ 5.001g 1995-May-25
+ 5.001h 1995-May-25
+ 5.001i 1995-May-30
+ 5.001j 1995-Jun-05
+ 5.001k 1995-Jun-06
+ 5.001l 1995-Jun-06 Stable.
+ 5.001m 1995-Jul-02 Very stable.
+ 5.001n 1995-Oct-31 Very unstable.
+ 5.002beta1 1995-Nov-21
+ 5.002b1a 1995-Dec-04
+ 5.002b1b 1995-Dec-04
+ 5.002b1c 1995-Dec-04
+ 5.002b1d 1995-Dec-04
+ 5.002b1e 1995-Dec-08
+ 5.002b1f 1995-Dec-08
+ Tom 5.002b1g 1995-Dec-21 Doc release.
+ Andy 5.002b1h 1996-Jan-05
+ 5.002b2 1996-Jan-14
+ Larry 5.002b3 1996-Feb-02
+ Andy 5.002gamma 1996-Feb-11
+ Larry 5.002delta 1996-Feb-27
+
+ Larry 5.002 1996-Feb-29 Prototypes.
+
+ Charles 5.002_01 1996-Mar-25
+
+ 5.003 1996-Jun-25 Security release.
+
+ 5.003_01 1996-Jul-31
+ Nick 5.003_02 1996-Aug-10
+ Andy 5.003_03 1996-Aug-28
+ 5.003_04 1996-Sep-02
+ 5.003_05 1996-Sep-12
+ 5.003_06 1996-Oct-07
+ 5.003_07 1996-Oct-10
+ Chip 5.003_08 1996-Nov-19
+ 5.003_09 1996-Nov-26
+ 5.003_10 1996-Nov-29
+ 5.003_11 1996-Dec-06
+ 5.003_12 1996-Dec-19
+ 5.003_13 1996-Dec-20
+ 5.003_14 1996-Dec-23
+ 5.003_15 1996-Dec-23
+ 5.003_16 1996-Dec-24
+ 5.003_17 1996-Dec-27
+ 5.003_18 1996-Dec-31
+ 5.003_19 1997-Jan-04
+ 5.003_20 1997-Jan-07
+ 5.003_21 1997-Jan-15
+ 5.003_22 1997-Jan-16
+ 5.003_23 1997-Jan-25
+ 5.003_24 1997-Jan-29
+ 5.003_25 1997-Feb-04
+ 5.003_26 1997-Feb-10
+ 5.003_27 1997-Feb-18
+ 5.003_28 1997-Feb-21
+ 5.003_90 1997-Feb-25 Ramping up to the 5.004 release.
+ 5.003_91 1997-Mar-01
+ 5.003_92 1997-Mar-06
+ 5.003_93 1997-Mar-10
+ 5.003_94 1997-Mar-22
+ 5.003_95 1997-Mar-25
+ 5.003_96 1997-Apr-01
+ 5.003_97 1997-Apr-03 Fairly widely used.
+ 5.003_97a 1997-Apr-05
+ 5.003_97b 1997-Apr-08
+ 5.003_97c 1997-Apr-10
+ 5.003_97d 1997-Apr-13
+ 5.003_97e 1997-Apr-15
+ 5.003_97f 1997-Apr-17
+ 5.003_97g 1997-Apr-18
+ 5.003_97h 1997-Apr-24
+ 5.003_97i 1997-Apr-25
+ 5.003_97j 1997-Apr-28
+ 5.003_98 1997-Apr-30
+ 5.003_99 1997-May-01
+ 5.003_99a 1997-May-09
+ p54rc1 1997-May-12 Release Candidates.
+ p54rc2 1997-May-14
+
+ Chip 5.004 1997-May-15 A major maintenance release.
+
+ Tim 5.004_01-t1 1997-???-?? The 5.004 maintenance track.
+ 5.004_01-t2 1997-Jun-11 aka perl5.004m1t2
+ 5.004_01 1997-Jun-13
+ 5.004_01_01 1997-Jul-29 aka perl5.004m2t1
+ 5.004_01_02 1997-Aug-01 aka perl5.004m2t2
+ 5.004_01_03 1997-Aug-05 aka perl5.004m2t3
+ 5.004_02 1997-Aug-07
+ 5.004_02_01 1997-Aug-12 aka perl5.004m3t1
+ 5.004_03-t2 1997-Aug-13 aka perl5.004m3t2
+ 5.004_03 1997-Sep-05
+ 5.004_04-t1 1997-Sep-19 aka perl5.004m4t1
+ 5.004_04-t2 1997-Sep-23 aka perl5.004m4t2
+ 5.004_04-t3 1997-Oct-10 aka perl5.004m4t3
+ 5.004_04-t4 1997-Oct-14 aka perl5.004m4t4
+ 5.004_04 1997-Oct-15
+ 5.004_04-m1 1998-Mar-04 (5.004m5t1) Maint. trials for 5.004_05.
+ 5.004_04-m2 1998-May-01
+ 5.004_04-m3 1998-May-15
+ 5.004_04-m4 1998-May-19
+ 5.004_05-MT5 1998-Jul-21
+ 5.004_05-MT6 1998-Oct-09
+ 5.004_05-MT7 1998-Nov-22
+ 5.004_05-MT8 1998-Dec-03
+ Chip 5.004_05-MT9 1999-Apr-26
+ 5.004_05 1999-Apr-29
+
+ Malcolm 5.004_50 1997-Sep-09 The 5.005 development track.
+ 5.004_51 1997-Oct-02
+ 5.004_52 1997-Oct-15
+ 5.004_53 1997-Oct-16
+ 5.004_54 1997-Nov-14
+ 5.004_55 1997-Nov-25
+ 5.004_56 1997-Dec-18
+ 5.004_57 1998-Feb-03
+ 5.004_58 1998-Feb-06
+ 5.004_59 1998-Feb-13
+ 5.004_60 1998-Feb-20
+ 5.004_61 1998-Feb-27
+ 5.004_62 1998-Mar-06
+ 5.004_63 1998-Mar-17
+ 5.004_64 1998-Apr-03
+ 5.004_65 1998-May-15
+ 5.004_66 1998-May-29
+ Sarathy 5.004_67 1998-Jun-15
+ 5.004_68 1998-Jun-23
+ 5.004_69 1998-Jun-29
+ 5.004_70 1998-Jul-06
+ 5.004_71 1998-Jul-09
+ 5.004_72 1998-Jul-12
+ 5.004_73 1998-Jul-13
+ 5.004_74 1998-Jul-14 5.005 beta candidate.
+ 5.004_75 1998-Jul-15 5.005 beta1.
+ 5.004_76 1998-Jul-21 5.005 beta2.
+
+ Sarathy 5.005 1998-Jul-22 Oneperl.
+
+ Sarathy 5.005_01 1998-Jul-27 The 5.005 maintenance track.
+ 5.005_02-T1 1998-Aug-02
+ 5.005_02-T2 1998-Aug-05
+ 5.005_02 1998-Aug-08
+ Graham 5.005_03-MT1 1998-Nov-30
+ 5.005_03-MT2 1999-Jan-04
+ 5.005_03-MT3 1999-Jan-17
+ 5.005_03-MT4 1999-Jan-26
+ 5.005_03-MT5 1999-Jan-28
+ 5.005_03-MT6 1999-Mar-05
+ 5.005_03 1999-Mar-28
+ Leon 5.005_04-RC1 2004-Feb-05
+ 5.005_04-RC2 2004-Feb-18
+ 5.005_04 2004-Feb-23
+
+ Sarathy 5.005_50 1998-Jul-26 The 5.6 development track.
+ 5.005_51 1998-Aug-10
+ 5.005_52 1998-Sep-25
+ 5.005_53 1998-Oct-31
+ 5.005_54 1998-Nov-30
+ 5.005_55 1999-Feb-16
+ 5.005_56 1999-Mar-01
+ 5.005_57 1999-May-25
+ 5.005_58 1999-Jul-27
+ 5.005_59 1999-Aug-02
+ 5.005_60 1999-Aug-02
+ 5.005_61 1999-Aug-20
+ 5.005_62 1999-Oct-15
+ 5.005_63 1999-Dec-09
+ 5.5.640 2000-Feb-02
+ 5.5.650 2000-Feb-08 beta1
+ 5.5.660 2000-Feb-22 beta2
+ 5.5.670 2000-Feb-29 beta3
+ 5.6.0-RC1 2000-Mar-09 Release candidate 1.
+ 5.6.0-RC2 2000-Mar-14 Release candidate 2.
+ 5.6.0-RC3 2000-Mar-21 Release candidate 3.
+
+ Sarathy 5.6.0 2000-Mar-22
+
+ Sarathy 5.6.1-TRIAL1 2000-Dec-18 The 5.6 maintenance track.
+ 5.6.1-TRIAL2 2001-Jan-31
+ 5.6.1-TRIAL3 2001-Mar-19
+ 5.6.1-foolish 2001-Apr-01 The "fools-gold" release.
+ 5.6.1 2001-Apr-08
+ Rafael 5.6.2-RC1 2003-Nov-08
+ 5.6.2 2003-Nov-15 Fix new build issues
+
+ Jarkko 5.7.0 2000-Sep-02 The 5.7 track: Development.
+ 5.7.1 2001-Apr-09
+ 5.7.2 2001-Jul-13 Virtual release candidate 0.
+ 5.7.3 2002-Mar-05
+ 5.8.0-RC1 2002-Jun-01
+ 5.8.0-RC2 2002-Jun-21
+ 5.8.0-RC3 2002-Jul-13
+
+ Jarkko 5.8.0 2002-Jul-18
+
+ Jarkko 5.8.1-RC1 2003-Jul-10 The 5.8 maintenance track
+ 5.8.1-RC2 2003-Jul-11
+ 5.8.1-RC3 2003-Jul-30
+ 5.8.1-RC4 2003-Aug-01
+ 5.8.1-RC5 2003-Sep-22
+ 5.8.1 2003-Sep-25
+ Nicholas 5.8.2-RC1 2003-Oct-27
+ 5.8.2-RC2 2003-Nov-03
+ 5.8.2 2003-Nov-05
+ 5.8.3-RC1 2004-Jan-07
+ 5.8.3 2004-Jan-14
+ 5.8.4-RC1 2004-Apr-05
+ 5.8.4-RC2 2004-Apr-15
+ 5.8.4 2004-Apr-21
+ 5.8.5-RC1 2004-Jul-06
+ 5.8.5-RC2 2004-Jul-08
+ 5.8.5 2004-Jul-19
+ 5.8.6-RC1 2004-Nov-11
+ 5.8.6 2004-Nov-27
+ 5.8.7-RC1 2005-May-18
+ 5.8.7 2005-May-30
+ 5.8.8-RC1 2006-Jan-20
+ 5.8.8 2006-Jan-31
+ 5.8.9-RC1 2008-Nov-10
+ 5.8.9-RC2 2008-Dec-06
+ 5.8.9 2008-Dec-14
+
+ Hugo 5.9.0 2003-Oct-27 The 5.9 development track
+ Rafael 5.9.1 2004-Mar-16
+ 5.9.2 2005-Apr-01
+ 5.9.3 2006-Jan-28
+ 5.9.4 2006-Aug-15
+ 5.9.5 2007-Jul-07
+ 5.10.0-RC1 2007-Nov-17
+ 5.10.0-RC2 2007-Nov-25
+
+ Rafael 5.10.0 2007-Dec-18
+
+ David 5.10.1-RC1 2009-Aug-06 The 5.10 maintenance track
+ 5.10.1-RC2 2009-Aug-18
+ 5.10.1 2009-Aug-22
+
+ Jesse 5.11.0 2009-Oct-02 The 5.11 development track
+ 5.11.1 2009-Oct-20
+ Leon 5.11.2 2009-Nov-20
+ Jesse 5.11.3 2009-Dec-20
+ Ricardo 5.11.4 2010-Jan-20
+ Steve 5.11.5 2010-Feb-20
+ Jesse 5.12.0-RC1 2010-Mar-29
+
+ Jesse 5.12.0 2010-Apr-12
+ Jesse 5.12.1 2010-May-16
+ Jesse 5.12.2 2010-Sep-06
+ Ricardo 5.12.3-RC1 2011-Jan-09
+ Ricardo 5.12.3-RC2 2011-Jan-14
+ Ricardo 5.12.3-RC3 2011-Jan-17
+ Ricardo 5.12.3 2011-Jan-21
+
+=head2 SELECTED RELEASE SIZES
+
+For example the notation "core: 212 29" in the release 1.000 means that
+it had in the core 212 kilobytes, in 29 files. The "core".."doc" are
+explained below.
+
+ release core lib ext t doc
+ ======================================================================
+
+ 1.000 212 29 - - - - 38 51 62 3
+ 1.014 219 29 - - - - 39 52 68 4
+ 2.000 309 31 2 3 - - 55 57 92 4
+ 2.001 312 31 2 3 - - 55 57 94 4
+ 3.000 508 36 24 11 - - 79 73 156 5
+ 3.044 645 37 61 20 - - 90 74 190 6
+ 4.000 635 37 59 20 - - 91 75 198 4
+ 4.019 680 37 85 29 - - 98 76 199 4
+ 4.036 709 37 89 30 - - 98 76 208 5
+ 5.000alpha2 785 50 114 32 - - 112 86 209 5
+ 5.000alpha3 801 50 117 33 - - 121 87 209 5
+ 5.000alpha9 1022 56 149 43 116 29 125 90 217 6
+ 5.000a12h 978 49 140 49 205 46 152 97 228 9
+ 5.000b3h 1035 53 232 70 216 38 162 94 218 21
+ 5.000 1038 53 250 76 216 38 154 92 536 62
+ 5.001m 1071 54 388 82 240 38 159 95 544 29
+ 5.002 1121 54 661 101 287 43 155 94 847 35
+ 5.003 1129 54 680 102 291 43 166 100 853 35
+ 5.003_07 1231 60 748 106 396 53 213 137 976 39
+ 5.004 1351 60 1230 136 408 51 355 161 1587 55
+ 5.004_01 1356 60 1258 138 410 51 358 161 1587 55
+ 5.004_04 1375 60 1294 139 413 51 394 162 1629 55
+ 5.004_05 1463 60 1435 150 394 50 445 175 1855 59
+ 5.004_51 1401 61 1260 140 413 53 358 162 1594 56
+ 5.004_53 1422 62 1295 141 438 70 394 162 1637 56
+ 5.004_56 1501 66 1301 140 447 74 408 165 1648 57
+ 5.004_59 1555 72 1317 142 448 74 424 171 1678 58
+ 5.004_62 1602 77 1327 144 629 92 428 173 1674 58
+ 5.004_65 1626 77 1358 146 615 92 446 179 1698 60
+ 5.004_68 1856 74 1382 152 619 92 463 187 1784 60
+ 5.004_70 1863 75 1456 154 675 92 494 194 1809 60
+ 5.004_73 1874 76 1467 152 762 102 506 196 1883 61
+ 5.004_75 1877 76 1467 152 770 103 508 196 1896 62
+ 5.005 1896 76 1469 152 795 103 509 197 1945 63
+ 5.005_03 1936 77 1541 153 813 104 551 201 2176 72
+ 5.005_50 1969 78 1842 301 795 103 514 198 1948 63
+ 5.005_53 1999 79 1885 303 806 104 602 224 2002 67
+ 5.005_56 2086 79 1970 307 866 113 672 238 2221 75
+ 5.6.0 2820 79 2626 364 1096 129 863 280 2840 93
+ 5.6.1 2946 78 2921 430 1171 132 1024 304 3330 102
+ 5.6.2 2947 78 3143 451 1247 127 1303 387 3406 102
+ 5.7.0 2977 80 2801 425 1250 132 975 307 3206 100
+ 5.7.1 3351 84 3442 455 1944 167 1334 357 3698 124
+ 5.7.2 3491 87 4858 618 3290 298 1598 449 3910 139
+ 5.7.3 3299 85 4295 537 2196 300 2176 626 4171 120
+ 5.8.0 3489 87 4533 585 2437 331 2588 726 4368 125
+ 5.8.1 3674 90 5104 623 2604 353 2983 836 4625 134
+ 5.8.2 3633 90 5111 623 2623 357 3019 848 4634 135
+ 5.8.3 3625 90 5141 624 2660 363 3083 869 4669 136
+ 5.8.4 3653 90 5170 634 2684 368 3148 885 4689 137
+ 5.8.5 3664 90 4260 303 2707 369 3208 898 4689 138
+ 5.8.6 3690 90 4271 303 3141 396 3411 925 4709 139
+ 5.8.7 3788 90 4322 307 3297 401 3485 964 4744 141
+ 5.8.8 3895 90 4357 314 3409 431 3622 1017 4979 144
+ 5.8.9 4132 93 5508 330 3826 529 4364 1234 5348 152
+ 5.9.0 3657 90 4951 626 2603 354 3011 841 4609 135
+ 5.9.1 3580 90 5196 634 2665 367 3186 889 4725 138
+ 5.9.2 3863 90 4654 312 3283 403 3551 973 4800 142
+ 5.9.3 4096 91 5318 381 4806 597 4272 1214 5139 147
+ 5.9.4 4393 94 5718 415 4578 642 4646 1310 5335 153
+ 5.9.5 4681 96 6849 479 4827 671 5155 1490 5572 159
+ 5.10.0 4710 97 7050 486 4899 673 5275 1503 5673 160
+ 5.10.1 4858 98 7440 519 6195 921 6147 1751 5151 163
+ 5.12.0 4999 100 1146 121 15227 2176 6400 1843 5342 168
+ 5.12.1 5000 100 1146 121 15283 2178 6407 1846 5354 169
+
+The "core"..."doc" mean the following files from the Perl source code
+distribution. The glob notation ** means recursively, (.) means
+regular files.
+
+ core *.[hcy]
+ lib lib/**/*.p[ml]
+ ext ext/**/*.{[hcyt],xs,pm} (for -5.10.1) or
+ {dist,ext,cpan}/**/*.{[hcyt],xs,pm} (for 5.12.0-)
+ t t/**/*(.) (for 1-5.005_56) or **/*.t (for 5.6.0-5.7.3)
+ doc {README*,INSTALL,*[_.]man{,.?},pod/**/*.pod}
+
+Here are some statistics for the other subdirectories and one file in
+the Perl source distribution for somewhat more selected releases.
+
+ ======================================================================
+ Legend: kB #
+
+ 1.014 2.001 3.044
+
+ Configure 31 1 37 1 62 1
+ eg - - 34 28 47 39
+ h2pl - - - - 12 12
+ msdos - - - - 41 13
+ os2 - - - - 63 22
+ usub - - - - 21 16
+ x2p 103 17 104 17 137 17
+
+ ======================================================================
+
+ 4.000 4.019 4.036
+
+ atarist - - - - 113 31
+ Configure 73 1 83 1 86 1
+ eg 47 39 47 39 47 39
+ emacs 67 4 67 4 67 4
+ h2pl 12 12 12 12 12 12
+ hints - - 5 42 11 56
+ msdos 57 15 58 15 60 15
+ os2 81 29 81 29 113 31
+ usub 25 7 43 8 43 8
+ x2p 147 18 152 19 154 19
+
+ ======================================================================
+
+ 5.000a2 5.000a12h 5.000b3h 5.000 5.001m
+
+ apollo 8 3 8 3 8 3 8 3 8 3
+ atarist 113 31 113 31 - - - - - -
+ bench - - 0 1 - - - - - -
+ Bugs 2 5 26 1 - - - - - -
+ dlperl 40 5 - - - - - - - -
+ do 127 71 - - - - - - - -
+ Configure - - 153 1 159 1 160 1 180 1
+ Doc - - 26 1 75 7 11 1 11 1
+ eg 79 58 53 44 51 43 54 44 54 44
+ emacs 67 4 104 6 104 6 104 1 104 6
+ h2pl 12 12 12 12 12 12 12 12 12 12
+ hints 11 56 12 46 18 48 18 48 44 56
+ msdos 60 15 60 15 - - - - - -
+ os2 113 31 113 31 - - - - - -
+ U - - 62 8 112 42 - - - -
+ usub 43 8 - - - - - - - -
+ vms - - 80 7 123 9 184 15 304 20
+ x2p 171 22 171 21 162 20 162 20 279 20
+
+ ======================================================================
+
+ 5.002 5.003 5.003_07
+
+ Configure 201 1 201 1 217 1
+ eg 54 44 54 44 54 44
+ emacs 108 1 108 1 143 1
+ h2pl 12 12 12 12 12 12
+ hints 73 59 77 60 90 62
+ os2 84 17 56 10 117 42
+ plan9 - - - - 79 15
+ Porting - - - - 51 1
+ utils 87 7 88 7 97 7
+ vms 500 24 475 26 505 27
+ x2p 280 20 280 20 280 19
+
+ ======================================================================
+
+ 5.004 5.004_04 5.004_62 5.004_65 5.004_68
+
+ beos - - - - - - 1 1 1 1
+ Configure 225 1 225 1 240 1 248 1 256 1
+ cygwin32 23 5 23 5 23 5 24 5 24 5
+ djgpp - - - - 14 5 14 5 14 5
+ eg 81 62 81 62 81 62 81 62 81 62
+ emacs 194 1 204 1 212 2 212 2 212 2
+ h2pl 12 12 12 12 12 12 12 12 12 12
+ hints 129 69 132 71 144 72 151 74 155 74
+ os2 121 42 127 42 127 44 129 44 129 44
+ plan9 82 15 82 15 82 15 82 15 82 15
+ Porting 94 2 109 4 203 6 234 8 241 9
+ qnx 1 2 1 2 1 2 1 2 1 2
+ utils 112 8 118 8 124 8 156 9 159 9
+ vms 518 34 524 34 538 34 569 34 569 34
+ win32 285 33 378 36 470 39 493 39 575 41
+ x2p 281 19 281 19 281 19 282 19 281 19
+
+ ======================================================================
+
+ 5.004_70 5.004_73 5.004_75 5.005 5.005_03
+
+ apollo - - - - - - - - 0 1
+ beos 1 1 1 1 1 1 1 1 1 1
+ Configure 256 1 256 1 264 1 264 1 270 1
+ cygwin32 24 5 24 5 24 5 24 5 24 5
+ djgpp 14 5 14 5 14 5 14 5 15 5
+ eg 86 65 86 65 86 65 86 65 86 65
+ emacs 262 2 262 2 262 2 262 2 274 2
+ h2pl 12 12 12 12 12 12 12 12 12 12
+ hints 157 74 157 74 159 74 160 74 179 77
+ mint - - - - - - - - 4 7
+ mpeix - - - - 5 3 5 3 5 3
+ os2 129 44 139 44 142 44 143 44 148 44
+ plan9 82 15 82 15 82 15 82 15 82 15
+ Porting 241 9 253 9 259 10 264 12 272 13
+ qnx 1 2 1 2 1 2 1 2 1 2
+ utils 160 9 160 9 160 9 160 9 164 9
+ vms 570 34 572 34 573 34 575 34 583 34
+ vos - - - - - - - - 156 10
+ win32 577 41 585 41 585 41 587 41 600 42
+ x2p 281 19 281 19 281 19 281 19 281 19
+
+ ======================================================================
+
+ 5.6.0 5.6.1 5.6.2 5.7.3
+
+ apollo 8 3 8 3 8 3 8 3
+ beos 5 2 5 2 5 2 6 4
+ Configure 346 1 361 1 363 1 394 1
+ Cross - - - - - - 4 2
+ djgpp 19 6 19 6 19 6 21 7
+ eg 112 71 112 71 112 71 - -
+ emacs 303 4 319 4 319 4 319 4
+ epoc 29 8 35 8 35 8 36 8
+ h2pl 24 15 24 15 24 15 24 15
+ hints 242 83 250 84 321 89 272 87
+ mint 11 9 11 9 11 9 11 9
+ mpeix 9 4 9 4 9 4 9 4
+ NetWare - - - - - - 423 57
+ os2 214 59 224 60 224 60 357 66
+ plan9 92 17 92 17 92 17 85 15
+ Porting 361 15 390 16 390 16 425 21
+ qnx 5 3 5 3 5 3 5 3
+ utils 228 12 221 11 222 11 267 13
+ uts - - - - - - 12 3
+ vmesa 25 4 25 4 25 4 25 4
+ vms 686 38 627 38 627 38 649 36
+ vos 227 12 249 15 248 15 281 17
+ win32 755 41 782 42 801 42 1006 50
+ x2p 307 20 307 20 307 20 345 20
+
+ ======================================================================
+
+ 5.8.0 5.8.1 5.8.2 5.8.3 5.8.4
+
+ apollo 8 3 8 3 8 3 8 3 8 3
+ beos 6 4 6 4 6 4 6 4 6 4
+ Configure 472 1 493 1 493 1 493 1 494 1
+ Cross 4 2 45 10 45 10 45 10 45 10
+ djgpp 21 7 21 7 21 7 21 7 21 7
+ emacs 319 4 329 4 329 4 329 4 329 4
+ epoc 33 8 33 8 33 8 33 8 33 8
+ h2pl 24 15 24 15 24 15 24 15 24 15
+ hints 294 88 321 89 321 89 321 89 348 91
+ mint 11 9 11 9 11 9 11 9 11 9
+ mpeix 24 5 25 5 25 5 25 5 25 5
+ NetWare 488 61 490 61 490 61 490 61 488 61
+ os2 361 66 445 67 450 67 488 67 488 67
+ plan9 85 15 325 17 325 17 325 17 321 17
+ Porting 479 22 537 32 538 32 539 32 538 33
+ qnx 5 3 5 3 5 3 5 3 5 3
+ utils 275 15 258 16 258 16 263 19 263 19
+ uts 12 3 12 3 12 3 12 3 12 3
+ vmesa 25 4 25 4 25 4 25 4 25 4
+ vms 648 36 654 36 654 36 656 36 656 36
+ vos 330 20 335 20 335 20 335 20 335 20
+ win32 1062 49 1125 49 1127 49 1126 49 1181 56
+ x2p 347 20 348 20 348 20 348 20 348 20
+
+ ======================================================================
+
+ 5.8.5 5.8.6 5.8.7 5.8.8 5.8.9
+
+ apollo 8 3 8 3 8 3 8 3 8 3
+ beos 6 4 6 4 8 4 8 4 8 4
+ Configure 494 1 494 1 495 1 506 1 520 1
+ Cross 45 10 45 10 45 10 45 10 46 10
+ djgpp 21 7 21 7 21 7 21 7 21 7
+ emacs 329 4 329 4 329 4 329 4 406 4
+ epoc 33 8 33 8 33 8 34 8 35 8
+ h2pl 24 15 24 15 24 15 24 15 24 15
+ hints 350 91 352 91 355 94 360 94 387 99
+ mint 11 9 11 9 11 9 11 9 11 9
+ mpeix 25 5 25 5 25 5 49 6 49 6
+ NetWare 488 61 488 61 488 61 490 61 491 61
+ os2 488 67 488 67 488 67 488 67 552 70
+ plan9 321 17 321 17 321 17 322 17 324 17
+ Porting 538 34 548 35 549 35 564 37 625 41
+ qnx 5 3 5 3 5 3 5 3 5 3
+ utils 265 19 265 19 266 19 267 19 281 21
+ uts 12 3 12 3 12 3 12 3 12 3
+ vmesa 25 4 25 4 25 4 25 4 25 4
+ vms 657 36 658 36 662 36 664 36 716 35
+ vos 335 20 335 20 335 20 336 21 345 22
+ win32 1183 56 1190 56 1199 56 1219 56 1484 68
+ x2p 349 20 349 20 349 20 349 19 350 19
+
+ ======================================================================
+
+ 5.9.0 5.9.1 5.9.2 5.9.3 5.9.4
+
+ apollo 8 3 8 3 8 3 8 3 8 3
+ beos 6 4 6 4 8 4 8 4 8 4
+ Configure 493 1 493 1 495 1 508 1 512 1
+ Cross 45 10 45 10 45 10 45 10 46 10
+ djgpp 21 7 21 7 21 7 21 7 21 7
+ emacs 329 4 329 4 329 4 329 4 329 4
+ epoc 33 8 33 8 33 8 34 8 34 8
+ h2pl 24 15 24 15 24 15 24 15 24 15
+ hints 321 89 346 91 355 94 359 94 366 96
+ mad - - - - - - - - 174 6
+ mint 11 9 11 9 11 9 11 9 11 9
+ mpeix 25 5 25 5 25 5 49 6 49 6
+ NetWare 489 61 487 61 487 61 489 61 489 61
+ os2 444 67 488 67 488 67 488 67 488 67
+ plan9 325 17 321 17 321 17 322 17 323 17
+ Porting 537 32 536 33 549 36 564 38 576 38
+ qnx 5 3 5 3 5 3 5 3 5 3
+ symbian - - - - - - 293 53 293 53
+ utils 258 16 263 19 268 20 273 23 275 24
+ uts 12 3 12 3 12 3 12 3 12 3
+ vmesa 25 4 25 4 25 4 25 4 25 4
+ vms 660 36 547 33 553 33 661 33 696 33
+ vos 11 7 11 7 11 7 11 7 11 7
+ win32 1120 49 1124 51 1191 56 1209 56 1719 90
+ x2p 348 20 348 20 349 20 349 19 349 19
+
+ ======================================================================
+
+ 5.9.5 5.10.0 5.10.1 5.12.0 5.12.1
+
+ apollo 8 3 8 3 0 3 0 3 0 3
+ beos 8 4 8 4 4 4 4 4 4 4
+ Configure 518 1 518 1 533 1 536 1 536 1
+ Cross 122 15 122 15 119 15 118 15 118 15
+ djgpp 21 7 21 7 17 7 17 7 17 7
+ emacs 329 4 406 4 402 4 402 4 402 4
+ epoc 34 8 35 8 31 8 31 8 31 8
+ h2pl 24 15 24 15 12 15 12 15 12 15
+ hints 377 98 381 98 385 100 368 97 368 97
+ mad 182 8 182 8 174 8 174 8 174 8
+ mint 11 9 11 9 3 9 - - - -
+ mpeix 49 6 49 6 45 6 45 6 45 6
+ NetWare 489 61 489 61 465 61 466 61 466 61
+ os2 552 70 552 70 507 70 507 70 507 70
+ plan9 324 17 324 17 316 17 316 17 316 17
+ Porting 627 40 632 40 933 53 749 54 749 54
+ qnx 5 3 5 4 1 4 1 4 1 4
+ symbian 300 54 300 54 290 54 288 54 288 54
+ utils 260 26 264 27 268 27 269 27 269 27
+ uts 12 3 12 3 8 3 8 3 8 3
+ vmesa 25 4 25 4 21 4 21 4 21 4
+ vms 690 32 722 32 693 30 645 18 645 18
+ vos 19 8 19 8 16 8 16 8 16 8
+ win32 1482 68 1485 68 1497 70 1841 73 1841 73
+ x2p 349 19 349 19 345 19 345 19 345 19
+
+=head2 SELECTED PATCH SIZES
+
+The "diff lines kB" means that for example the patch 5.003_08, to be
+applied on top of the 5.003_07 (or whatever was before the 5.003_08)
+added lines for 110 kilobytes, it removed lines for 19 kilobytes, and
+changed lines for 424 kilobytes. Just the lines themselves are
+counted, not their context. The "+ - !" become from the diff(1)
+context diff output format.
+
+ Pump- Release Date diff lines kB
+ king -------------
+ + - !
+ ======================================================================
+
+ Chip 5.003_08 1996-Nov-19 110 19 424
+ 5.003_09 1996-Nov-26 38 9 248
+ 5.003_10 1996-Nov-29 29 2 27
+ 5.003_11 1996-Dec-06 73 12 165
+ 5.003_12 1996-Dec-19 275 6 436
+ 5.003_13 1996-Dec-20 95 1 56
+ 5.003_14 1996-Dec-23 23 7 333
+ 5.003_15 1996-Dec-23 0 0 1
+ 5.003_16 1996-Dec-24 12 3 50
+ 5.003_17 1996-Dec-27 19 1 14
+ 5.003_18 1996-Dec-31 21 1 32
+ 5.003_19 1997-Jan-04 80 3 85
+ 5.003_20 1997-Jan-07 18 1 146
+ 5.003_21 1997-Jan-15 38 10 221
+ 5.003_22 1997-Jan-16 4 0 18
+ 5.003_23 1997-Jan-25 71 15 119
+ 5.003_24 1997-Jan-29 426 1 20
+ 5.003_25 1997-Feb-04 21 8 169
+ 5.003_26 1997-Feb-10 16 1 15
+ 5.003_27 1997-Feb-18 32 10 38
+ 5.003_28 1997-Feb-21 58 4 66
+ 5.003_90 1997-Feb-25 22 2 34
+ 5.003_91 1997-Mar-01 37 1 39
+ 5.003_92 1997-Mar-06 16 3 69
+ 5.003_93 1997-Mar-10 12 3 15
+ 5.003_94 1997-Mar-22 407 7 200
+ 5.003_95 1997-Mar-25 41 1 37
+ 5.003_96 1997-Apr-01 283 5 261
+ 5.003_97 1997-Apr-03 13 2 34
+ 5.003_97a 1997-Apr-05 57 1 27
+ 5.003_97b 1997-Apr-08 14 1 20
+ 5.003_97c 1997-Apr-10 20 1 16
+ 5.003_97d 1997-Apr-13 8 0 16
+ 5.003_97e 1997-Apr-15 15 4 46
+ 5.003_97f 1997-Apr-17 7 1 33
+ 5.003_97g 1997-Apr-18 6 1 42
+ 5.003_97h 1997-Apr-24 23 3 68
+ 5.003_97i 1997-Apr-25 23 1 31
+ 5.003_97j 1997-Apr-28 36 1 49
+ 5.003_98 1997-Apr-30 171 12 539
+ 5.003_99 1997-May-01 6 0 7
+ 5.003_99a 1997-May-09 36 2 61
+ p54rc1 1997-May-12 8 1 11
+ p54rc2 1997-May-14 6 0 40
+
+ 5.004 1997-May-15 4 0 4
+
+ Tim 5.004_01 1997-Jun-13 222 14 57
+ 5.004_02 1997-Aug-07 112 16 119
+ 5.004_03 1997-Sep-05 109 0 17
+ 5.004_04 1997-Oct-15 66 8 173
+
+=head3 The patch-free era
+
+In more modern times, named releases don't come as often, and as progress
+can be followed (nearly) instantly (with rsync, and since late 2008, git)
+patches between versions are no longer provided. However, that doesn't
+keep us from calculating how large a patch could have been. Which is
+shown in the table below. Unless noted otherwise, the size mentioned is
+the patch to bring version x.y.z to x.y.z+1.
+
+ Sarathy 5.6.1 2001-Apr-08 531 44 651
+ Rafael 5.6.2 2003-Nov-15 20 11 1819
+
+ Jarkko 5.8.0 2002-Jul-18 1205 31 471 From 5.7.3
+
+ 5.8.1 2003-Sep-25 243 102 6162
+ Nicholas 5.8.2 2003-Nov-05 10 50 788
+ 5.8.3 2004-Jan-14 31 13 360
+ 5.8.4 2004-Apr-21 33 8 299
+ 5.8.5 2004-Jul-19 11 19 255
+ 5.8.6 2004-Nov-27 35 3 192
+ 5.8.7 2005-May-30 75 34 778
+ 5.8.8 2006-Jan-31 131 42 1251
+ 5.8.9 2008-Dec-14 340 132 12988
+
+ Hugo 5.9.0 2003-Oct-27 281 168 7132 From 5.8.0
+ Rafael 5.9.1 2004-Mar-16 57 250 2107
+ 5.9.2 2005-Apr-01 720 57 858
+ 5.9.3 2006-Jan-28 1124 102 1906
+ 5.9.4 2006-Aug-15 896 60 862
+ 5.9.5 2007-Jul-07 1149 128 1062
+
+ 5.10.0 2007-Dec-18 50 31 13111 From 5.9.5
+
+
+=head1 THE KEEPERS OF THE RECORDS
+
+Jarkko Hietaniemi <F<jhi@iki.fi>>.
+
+Thanks to the collective memory of the Perlfolk. In addition to the
+Keepers of the Pumpkin also Alan Champion, Mark Dominus,
+Andreas König, John Macdonald, Matthias Neeracher, Jeff Okamoto,
+Michael Peppler, Randal Schwartz, and Paul D. Smith sent corrections
+and additions. Abigail added file and patch size data for the 5.6.0 - 5.10
+era.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlhpux.pod b/Master/tlpkg/tlperl/lib/pods/perlhpux.pod
new file mode 100644
index 00000000000..df3e6a8ef41
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlhpux.pod
@@ -0,0 +1,657 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.hpux - Perl version 5 on Hewlett-Packard Unix (HP-UX) systems
+
+=head1 DESCRIPTION
+
+This document describes various features of HP's Unix operating system
+(HP-UX) that will affect how Perl version 5 (hereafter just Perl) is
+compiled and/or runs.
+
+=head2 Using perl as shipped with HP-UX
+
+Application release September 2001, HP-UX 11.00 is the first to ship
+with Perl. By the time it was perl-5.6.1 in /opt/perl. The first
+occurrence is on CD 5012-7954 and can be installed using
+
+ swinstall -s /cdrom perl
+
+assuming you have mounted that CD on /cdrom. In this version the
+following modules were installed:
+
+ ActivePerl::DocTools-0.04 HTML::Parser-3.19 XML::DOM-1.25
+ Archive::Tar-0.072 HTML::Tagset-3.03 XML::Parser-2.27
+ Compress::Zlib-1.08 MIME::Base64-2.11 XML::Simple-1.05
+ Convert::ASN1-0.10 Net-1.07 XML::XPath-1.09
+ Digest::MD5-2.11 PPM-2.1.5 XML::XSLT-0.32
+ File::CounterFile-0.12 SOAP::Lite-0.46 libwww-perl-5.51
+ Font::AFM-1.18 Storable-1.011 libxml-perl-0.07
+ HTML-Tree-3.11 URI-1.11 perl-ldap-0.23
+
+That build was a portable hppa-1.1 multithread build that supports large
+files compiled with gcc-2.9-hppa-991112.
+
+If you perform a new installation, then (a newer) Perl will be installed
+automatically. Preinstalled HP-UX systems now slao have more recent versions
+of Perl and the updated modules.
+
+The official (threaded) builds from HP, as they are shipped on the
+Application DVD/CD's are available on
+http://www.software.hp.com/portal/swdepot/displayProductInfo.do?productNumber=PERL
+for both PA-RISC and IPF (Itanium Processor Family). They are built
+with the HP ANSI-C compiler. Up till 5.8.8 that was done by ActiveState.
+
+To see what version is included on the DVD (assumed here to be mounted
+on /cdrom), issue this command:
+
+ # swlist -s /cdrom perl
+ # perl D.5.8.8.B 5.8.8 Perl Programming Language
+ perl.Perl5-32 D.5.8.8.B 32-bit 5.8.8 Perl Programming Language with Extensions
+ perl.Perl5-64 D.5.8.8.B 64-bit 5.8.8 Perl Programming Language with Extensions
+
+=head2 Using perl from HP's porting centre
+
+HP porting centre tries very hard to keep up with customer demand and
+release updates from the Open Source community. Having precompiled
+Perl binaries available is obvious.
+
+The HP porting centres are limited in what systems they are allowed
+to port to and they usually choose the two most recent OS versions
+available. This means that at the moment of writing, there are only
+HP-UX 11.11 (pa-risc 2.0) and HP-UX 11.23 (Itanium 2) ports available
+on the porting centres.
+
+HP has asked the porting centre to move Open Source binaries
+from /opt to /usr/local, so binaries produced since the start
+of July 2002 are located in /usr/local.
+
+One of HP porting centres URL's is http://hpux.connect.org.uk/
+The port currently available is built with GNU gcc.
+
+=head2 Compiling Perl 5 on HP-UX
+
+When compiling Perl, you must use an ANSI C compiler. The C compiler
+that ships with all HP-UX systems is a K&R compiler that should only be
+used to build new kernels.
+
+Perl can be compiled with either HP's ANSI C compiler or with gcc. The
+former is recommended, as not only can it compile Perl with no
+difficulty, but also can take advantage of features listed later that
+require the use of HP compiler-specific command-line flags.
+
+If you decide to use gcc, make sure your installation is recent and
+complete, and be sure to read the Perl INSTALL file for more gcc-specific
+details.
+
+=head2 PA-RISC
+
+HP's HP9000 Unix systems run on HP's own Precision Architecture
+(PA-RISC) chip. HP-UX used to run on the Motorola MC68000 family of
+chips, but any machine with this chip in it is quite obsolete and this
+document will not attempt to address issues for compiling Perl on the
+Motorola chipset.
+
+The version of PA-RISC at the time of this document's last update is 2.0,
+which is also the last there will be. HP PA-RISC systems are usually
+refered to with model description "HP 9000". The last CPU in this series
+is the PA-8900. Support for PA-RISC architectured machines officially
+ends as shown in the following table:
+
+ PA-RISC End-of-Life Roadmap
+ +--------+----------------+----------------+-----------------+
+ | HP9000 | Superdome | PA-8700 | Spring 2011 |
+ | 4-128 | | PA-8800/sx1000 | Summer 2012 |
+ | cores | | PA-8900/sx1000 | 2014 |
+ | | | PA-8900/sx2000 | 2015 |
+ +--------+----------------+----------------+-----------------+
+ | HP9000 | rp7410, rp8400 | PA-8700 | Spring 2011 |
+ | 2-32 | rp7420, rp8420 | PA-8800/sx1000 | 2012 |
+ | cores | rp7440, rp8440 | PA-8900/sx1000 | Autumn 2013 |
+ | | | PA-8900/sx2000 | 2015 |
+ +--------+----------------+----------------+-----------------+
+ | HP9000 | rp44x0 | PA-8700 | Spring 2011 |
+ | 1-8 | | PA-8800/rp44x0 | 2012 |
+ | cores | | PA-8900/rp44x0 | 2014 |
+ +--------+----------------+----------------+-----------------+
+ | HP9000 | rp34x0 | PA-8700 | Spring 2011 |
+ | 1-4 | | PA-8800/rp34x0 | 2012 |
+ | cores | | PA-8900/rp34x0 | 2014 |
+ +--------+----------------+----------------+-----------------+
+
+From http://www.hp.com/products1/evolution/9000/faqs.html
+
+ The last order date for HP 9000 systems was December 31, 2008.
+
+A complete list of models at the time the OS was built is in the file
+/usr/sam/lib/mo/sched.models. The first column corresponds to the last
+part of the output of the "model" command. The second column is the
+PA-RISC version and the third column is the exact chip type used.
+(Start browsing at the bottom to prevent confusion ;-)
+
+ # model
+ 9000/800/L1000-44
+ # grep L1000-44 /usr/sam/lib/mo/sched.models
+ L1000-44 2.0 PA8500
+
+=head2 Portability Between PA-RISC Versions
+
+An executable compiled on a PA-RISC 2.0 platform will not execute on a
+PA-RISC 1.1 platform, even if they are running the same version of
+HP-UX. If you are building Perl on a PA-RISC 2.0 platform and want that
+Perl to also run on a PA-RISC 1.1, the compiler flags +DAportable and
++DS32 should be used.
+
+It is no longer possible to compile PA-RISC 1.0 executables on either
+the PA-RISC 1.1 or 2.0 platforms. The command-line flags are accepted,
+but the resulting executable will not run when transferred to a PA-RISC
+1.0 system.
+
+=head2 PA-RISC 1.0
+
+The original version of PA-RISC, HP no longer sells any system with this chip.
+
+The following systems contained PA-RISC 1.0 chips:
+
+ 600, 635, 645, 808, 815, 822, 825, 832, 834, 835, 840, 842, 845, 850,
+ 852, 855, 860, 865, 870, 890
+
+=head2 PA-RISC 1.1
+
+An upgrade to the PA-RISC design, it shipped for many years in many different
+system.
+
+The following systems contain with PA-RISC 1.1 chips:
+
+ 705, 710, 712, 715, 720, 722, 725, 728, 730, 735, 742, 743, 744, 745,
+ 747, 750, 755, 770, 777, 778, 779, 800, 801, 803, 806, 807, 809, 811,
+ 813, 816, 817, 819, 821, 826, 827, 829, 831, 837, 839, 841, 847, 849,
+ 851, 856, 857, 859, 867, 869, 877, 887, 891, 892, 897, A180, A180C,
+ B115, B120, B132L, B132L+, B160L, B180L, C100, C110, C115, C120,
+ C160L, D200, D210, D220, D230, D250, D260, D310, D320, D330, D350,
+ D360, D410, DX0, DX5, DXO, E25, E35, E45, E55, F10, F20, F30, G30,
+ G40, G50, G60, G70, H20, H30, H40, H50, H60, H70, I30, I40, I50, I60,
+ I70, J200, J210, J210XC, K100, K200, K210, K220, K230, K400, K410,
+ K420, S700i, S715, S744, S760, T500, T520
+
+=head2 PA-RISC 2.0
+
+The most recent upgrade to the PA-RISC design, it added support for
+64-bit integer data.
+
+As of the date of this document's last update, the following systems
+contain PA-RISC 2.0 chips:
+
+ 700, 780, 781, 782, 783, 785, 802, 804, 810, 820, 861, 871, 879, 889,
+ 893, 895, 896, 898, 899, A400, A500, B1000, B2000, C130, C140, C160,
+ C180, C180+, C180-XP, C200+, C400+, C3000, C360, C3600, CB260, D270,
+ D280, D370, D380, D390, D650, J220, J2240, J280, J282, J400, J410,
+ J5000, J5500XM, J5600, J7000, J7600, K250, K260, K260-EG, K270, K360,
+ K370, K380, K450, K460, K460-EG, K460-XP, K470, K570, K580, L1000,
+ L2000, L3000, N4000, R380, R390, SD16000, SD32000, SD64000, T540,
+ T600, V2000, V2200, V2250, V2500, V2600
+
+Just before HP took over Compaq, some systems were renamed. the link
+that contained the explanation is dead, so here's a short summary:
+
+ HP 9000 A-Class servers, now renamed HP Server rp2400 series.
+ HP 9000 L-Class servers, now renamed HP Server rp5400 series.
+ HP 9000 N-Class servers, now renamed HP Server rp7400.
+
+ rp2400, rp2405, rp2430, rp2450, rp2470, rp3410, rp3440, rp4410,
+ rp4440, rp5400, rp5405, rp5430, rp5450, rp5470, rp7400, rp7405,
+ rp7410, rp7420, rp7440, rp8400, rp8420, rp8440, Superdome
+
+The current naming convention is:
+
+ aadddd
+ ||||`+- 00 - 99 relative capacity & newness (upgrades, etc.)
+ |||`--- unique number for each architecture to ensure different
+ ||| systems do not have the same numbering across
+ ||| architectures
+ ||`---- 1 - 9 identifies family and/or relative positioning
+ ||
+ |`----- c = ia32 (cisc)
+ | p = pa-risc
+ | x = ia-64 (Itanium & Itanium 2)
+ | h = housing
+ `------ t = tower
+ r = rack optimized
+ s = super scalable
+ b = blade
+ sa = appliance
+
+=head2 Itanium Processor Family (IPF) and HP-UX
+
+HP-UX also runs on the new Itanium processor. This requires the use
+of a different version of HP-UX (currently 11.23 or 11i v2), and with
+the exception of a few differences detailed below and in later sections,
+Perl should compile with no problems.
+
+Although PA-RISC binaries can run on Itanium systems, you should not
+attempt to use a PA-RISC version of Perl on an Itanium system. This is
+because shared libraries created on an Itanium system cannot be loaded
+while running a PA-RISC executable.
+
+HP Itanium 2 systems are usually refered to with model description
+"HP Integrity".
+
+=head2 Itanium, Itanium 2 & Madison 6
+
+HP also ships servers with the 128-bit Itanium processor(s). The cx26x0
+is told to have Madison 6. As of the date of this document's last update,
+the following systems contain Itanium or Itanium 2 chips (this is likely
+to be out of date):
+
+ BL60p, BL860c, BL870c, cx2600, cx2620, rx1600, rx1620, rx2600,
+ rx2600hptc, rx2620, rx2660, rx3600, rx4610, rx4640, rx5670,
+ rx6600, rx7420, rx7620, rx7640, rx8420, rx8620, rx8640, rx9610,
+ sx1000, sx2000
+
+To see all about your machine, type
+
+ # model
+ ia64 hp server rx2600
+ # /usr/contrib/bin/machinfo
+
+=head2 HP-UX versions
+
+Not all architectures (PA = PA-RISC, IPF = Itanium Processor Family)
+support all versions of HP-UX, here is a short list
+
+ HP-UX version Kernel Architecture
+ ------------- ------ ------------
+ 10.20 32 bit PA
+ 11.00 32/64 PA
+ 11.11 11i v1 32/64 PA
+ 11.22 11i v2 64 IPF
+ 11.23 11i v2 64 PA & IPF
+ 11.31 11i v3 64 PA & IPF
+
+See for the full list of hardware/OS support and expected end-of-life
+http://www.hp.com/go/hpuxservermatrix
+
+=head2 Building Dynamic Extensions on HP-UX
+
+HP-UX supports dynamically loadable libraries (shared libraries).
+Shared libraries end with the suffix .sl. On Itanium systems,
+they end with the suffix .so.
+
+Shared libraries created on a platform using a particular PA-RISC
+version are not usable on platforms using an earlier PA-RISC version by
+default. However, this backwards compatibility may be enabled using the
+same +DAportable compiler flag (with the same PA-RISC 1.0 caveat
+mentioned above).
+
+Shared libraries created on an Itanium platform cannot be loaded on
+a PA-RISC platform. Shared libraries created on a PA-RISC platform
+can only be loaded on an Itanium platform if it is a PA-RISC executable
+that is attempting to load the PA-RISC library. A PA-RISC shared
+library cannot be loaded into an Itanium executable nor vice-versa.
+
+To create a shared library, the following steps must be performed:
+
+ 1. Compile source modules with +z or +Z flag to create a .o module
+ which contains Position-Independent Code (PIC). The linker will
+ tell you in the next step if +Z was needed.
+ (For gcc, the appropriate flag is -fpic or -fPIC.)
+
+ 2. Link the shared library using the -b flag. If the code calls
+ any functions in other system libraries (e.g., libm), it must
+ be included on this line.
+
+(Note that these steps are usually handled automatically by the extension's
+Makefile).
+
+If these dependent libraries are not listed at shared library creation
+time, you will get fatal "Unresolved symbol" errors at run time when the
+library is loaded.
+
+You may create a shared library that refers to another library, which
+may be either an archive library or a shared library. If this second
+library is a shared library, this is called a "dependent library". The
+dependent library's name is recorded in the main shared library, but it
+is not linked into the shared library. Instead, it is loaded when the
+main shared library is loaded. This can cause problems if you build an
+extension on one system and move it to another system where the
+libraries may not be located in the same place as on the first system.
+
+If the referred library is an archive library, then it is treated as a
+simple collection of .o modules (all of which must contain PIC). These
+modules are then linked into the shared library.
+
+Note that it is okay to create a library which contains a dependent
+library that is already linked into perl.
+
+Some extensions, like DB_File and Compress::Zlib use/require prebuilt
+libraries for the perl extensions/modules to work. If these libraries
+are built using the default configuration, it might happen that you
+run into an error like "invalid loader fixup" during load phase.
+HP is aware of this problem. Search the HP-UX cxx-dev forums for
+discussions about the subject. The short answer is that B<everything>
+(all libraries, everything) must be compiled with C<+z> or C<+Z> to be
+PIC (position independent code). (For gcc, that would be
+C<-fpic> or C<-fPIC>). In HP-UX 11.00 or newer the linker
+error message should tell the name of the offending object file.
+
+A more general approach is to intervene manually, as with an example for
+the DB_File module, which requires SleepyCat's libdb.sl:
+
+ # cd .../db-3.2.9/build_unix
+ # vi Makefile
+ ... add +Z to all cflags to create shared objects
+ CFLAGS= -c $(CPPFLAGS) +Z -Ae +O2 +Onolimit \
+ -I/usr/local/include -I/usr/include/X11R6
+ CXXFLAGS= -c $(CPPFLAGS) +Z -Ae +O2 +Onolimit \
+ -I/usr/local/include -I/usr/include/X11R6
+
+ # make clean
+ # make
+ # mkdir tmp
+ # cd tmp
+ # ar x ../libdb.a
+ # ld -b -o libdb-3.2.sl *.o
+ # mv libdb-3.2.sl /usr/local/lib
+ # rm *.o
+ # cd /usr/local/lib
+ # rm -f libdb.sl
+ # ln -s libdb-3.2.sl libdb.sl
+
+ # cd .../DB_File-1.76
+ # make distclean
+ # perl Makefile.PL
+ # make
+ # make test
+ # make install
+
+As of db-4.2.x it is no longer needed to do this by hand. Sleepycat
+has changed the configuration process to add +z on HP-UX automatically.
+
+ # cd .../db-4.2.25/build_unix
+ # env CFLAGS=+DD64 LDFLAGS=+DD64 ../dist/configure
+
+should work to generate 64bit shared libraries for HP-UX 11.00 and 11i.
+
+It is no longer possible to link PA-RISC 1.0 shared libraries (even
+though the command-line flags are still present).
+
+PA-RISC and Itanium object files are not interchangeable. Although
+you may be able to use ar to create an archive library of PA-RISC
+object files on an Itanium system, you cannot link against it using
+an Itanium link editor.
+
+=head2 The HP ANSI C Compiler
+
+When using this compiler to build Perl, you should make sure that the
+flag -Aa is added to the cpprun and cppstdin variables in the config.sh
+file (though see the section on 64-bit perl below). If you are using a
+recent version of the Perl distribution, these flags are set automatically.
+
+Even though HP-UX 10.20 and 11.00 are not actively maintained by HP
+anymore, updates for the HP ANSI C compiler are still available from
+time to time, and it might be advisable to see if updates are applicable.
+At the moment of writing, the latests available patches for 11.00 that
+should be applied are PHSS_35098, PHSS_35175, PHSS_35100, PHSS_33036,
+and PHSS_33902). If you have a SUM account, you can use it to search
+for updates/patches. Enter "ANSI" as keyword.
+
+=head2 The GNU C Compiler
+
+When you are going to use the GNU C compiler (gcc), and you don't have
+gcc yet, you can either build it yourself from the sources (available
+from e.g. http://www.gnu.ai.mit.edu/software/gcc/releases.html) or fetch
+a prebuilt binary from the HP porting center. gcc prebuilds can be
+fetched from
+http://h21007.www2.hp.com/dspp/tech/tech_TechSoftwareDetailPage_IDX/1,1703,547,00.html
+(Browse through the list, because there are often multiple versions of
+the same package available).
+
+Above mentioned distributions are depots. H.Merijn Brand has made prebuilt
+gcc binaries available on http://mirrors.develooper.com/hpux/ and/or
+http://www.cmve.net/~merijn/ for HP-UX 10.20, HP-UX 11.00, HP-UX 11.11
+(HP-UX 11i v1), and HP-UX 11.23 (HP-UX 11i v2) in both 32- and 64-bit
+versions. These are bzipped tar archives that also include recent GNU
+binutils and GNU gdb. Read the instructions on that page to rebuild gcc
+using itself.
+
+On PA-RISC you need a different compiler for 32-bit applications and for
+64-bit applications. On PA-RISC, 32-bit objects and 64-bit objects do
+not mix. Period. There is no different behaviour for HP C-ANSI-C or GNU
+gcc. So if you require your perl binary to use 64-bit libraries, like
+Oracle-64bit, you MUST build a 64-bit perl.
+
+Building a 64-bit capable gcc on PA-RISC from source is possible only when
+you have the HP C-ANSI C compiler or an already working 64-bit binary of
+gcc available. Best performance for perl is achieved with HP's native
+compiler.
+
+=head2 Using Large Files with Perl on HP-UX
+
+Beginning with HP-UX version 10.20, files larger than 2GB (2^31 bytes)
+may be created and manipulated. Three separate methods of doing this
+are available. Of these methods, the best method for Perl is to compile
+using the -Duselargefiles flag to Configure. This causes Perl to be
+compiled using structures and functions in which these are 64 bits wide,
+rather than 32 bits wide. (Note that this will only work with HP's ANSI
+C compiler. If you want to compile Perl using gcc, you will have to get
+a version of the compiler that supports 64-bit operations. See above for
+where to find it.)
+
+There are some drawbacks to this approach. One is that any extension
+which calls any file-manipulating C function will need to be recompiled
+(just follow the usual "perl Makefile.PL; make; make test; make install"
+procedure).
+
+The list of functions that will need to recompiled is:
+ creat, fgetpos, fopen,
+ freopen, fsetpos, fstat,
+ fstatvfs, fstatvfsdev, ftruncate,
+ ftw, lockf, lseek,
+ lstat, mmap, nftw,
+ open, prealloc, stat,
+ statvfs, statvfsdev, tmpfile,
+ truncate, getrlimit, setrlimit
+
+Another drawback is only valid for Perl versions before 5.6.0. This
+drawback is that the seek and tell functions (both the builtin version
+and POSIX module version) will not perform correctly.
+
+It is strongly recommended that you use this flag when you run
+Configure. If you do not do this, but later answer the question about
+large files when Configure asks you, you may get a configuration that
+cannot be compiled, or that does not function as expected.
+
+=head2 Threaded Perl on HP-UX
+
+It is possible to compile a version of threaded Perl on any version of
+HP-UX before 10.30, but it is strongly suggested that you be running on
+HP-UX 11.00 at least.
+
+To compile Perl with threads, add -Dusethreads to the arguments of
+Configure. Verify that the -D_POSIX_C_SOURCE=199506L compiler flag is
+automatically added to the list of flags. Also make sure that -lpthread
+is listed before -lc in the list of libraries to link Perl with. The
+hints provided for HP-UX during Configure will try very hard to get
+this right for you.
+
+HP-UX versions before 10.30 require a separate installation of a POSIX
+threads library package. Two examples are the HP DCE package, available
+on "HP-UX Hardware Extensions 3.0, Install and Core OS, Release 10.20,
+April 1999 (B3920-13941)" or the Freely available PTH package, available
+on H.Merijn's site (http://mirrors.develooper.com/hpux/). The use of PTH
+will be unsupported in perl-5.12 and up and is rather buggy in 5.11.x.
+
+If you are going to use the HP DCE package, the library used for threading
+is /usr/lib/libcma.sl, but there have been multiple updates of that
+library over time. Perl will build with the first version, but it
+will not pass the test suite. Older Oracle versions might be a compelling
+reason not to update that library, otherwise please find a newer version
+in one of the following patches: PHSS_19739, PHSS_20608, or PHSS_23672
+
+reformatted output:
+
+ d3:/usr/lib 106 > what libcma-*.1
+ libcma-00000.1:
+ HP DCE/9000 1.5 Module: libcma.sl (Export)
+ Date: Apr 29 1996 22:11:24
+ libcma-19739.1:
+ HP DCE/9000 1.5 PHSS_19739-40 Module: libcma.sl (Export)
+ Date: Sep 4 1999 01:59:07
+ libcma-20608.1:
+ HP DCE/9000 1.5 PHSS_20608 Module: libcma.1 (Export)
+ Date: Dec 8 1999 18:41:23
+ libcma-23672.1:
+ HP DCE/9000 1.5 PHSS_23672 Module: libcma.1 (Export)
+ Date: Apr 9 2001 10:01:06
+ d3:/usr/lib 107 >
+
+If you choose for the PTH package, use swinstall to install pth in
+the default location (/opt/pth), and then make symbolic links to the
+libraries from /usr/lib
+
+ # cd /usr/lib
+ # ln -s /opt/pth/lib/libpth* .
+
+For building perl to support Oracle, it needs to be linked with libcl
+and libpthread. So even if your perl is an unthreaded build, these
+libraries might be required. See "Oracle on HP-UX" below.
+
+=head2 64-bit Perl on HP-UX
+
+Beginning with HP-UX 11.00, programs compiled under HP-UX can take
+advantage of the LP64 programming environment (LP64 means Longs and
+Pointers are 64 bits wide), in which scalar variables will be able
+to hold numbers larger than 2^32 with complete precision. Perl has
+proven to be consistent and reliable in 64bit mode since 5.8.1 on
+all HP-UX 11.xx.
+
+As of the date of this document, Perl is fully 64-bit compliant on
+HP-UX 11.00 and up for both cc- and gcc builds. If you are about to
+build a 64-bit perl with GNU gcc, please read the gcc section carefully.
+
+Should a user have the need for compiling Perl in the LP64 environment,
+use the -Duse64bitall flag to Configure. This will force Perl to be
+compiled in a pure LP64 environment (with the +DD64 flag for HP C-ANSI-C,
+with no additional options for GNU gcc 64-bit on PA-RISC, and with
+-mlp64 for GNU gcc on Itanium).
+If you want to compile Perl using gcc, you will have to get a version of
+the compiler that supports 64-bit operations.)
+
+You can also use the -Duse64bitint flag to Configure. Although there
+are some minor differences between compiling Perl with this flag versus
+the -Duse64bitall flag, they should not be noticeable from a Perl user's
+perspective. When configuring -Duse64bitint using a 64bit gcc on a
+pa-risc architecture, -Duse64bitint is silently promoted to -Duse64bitall.
+
+In both cases, it is strongly recommended that you use these flags when
+you run Configure. If you do not use do this, but later answer the
+questions about 64-bit numbers when Configure asks you, you may get a
+configuration that cannot be compiled, or that does not function as
+expected.
+
+=head2 Oracle on HP-UX
+
+Using perl to connect to Oracle databases through DBI and DBD::Oracle
+has caused a lot of people many headaches. Read README.hpux in the
+DBD::Oracle for much more information. The reason to mention it here
+is that Oracle requires a perl built with libcl and libpthread, the
+latter even when perl is build without threads. Building perl using
+all defaults, but still enabling to build DBD::Oracle later on can be
+achieved using
+
+ Configure -A prepend:libswanted='cl pthread ' ...
+
+Do not forget the space before the trailing quote.
+
+Also note that this does not (yet) work with all configurations,
+it is known to fail with 64-bit versions of GCC.
+
+=head2 GDBM and Threads on HP-UX
+
+If you attempt to compile Perl with (POSIX) threads on an 11.X system
+and also link in the GDBM library, then Perl will immediately core dump
+when it starts up. The only workaround at this point is to relink the
+GDBM library under 11.X, then relink it into Perl.
+
+the error might show something like:
+
+Pthread internal error: message: __libc_reinit() failed, file: ../pthreads/pthread.c, line: 1096
+Return Pointer is 0xc082bf33
+sh: 5345 Quit(coredump)
+
+and Configure will give up.
+
+=head2 NFS filesystems and utime(2) on HP-UX
+
+If you are compiling Perl on a remotely-mounted NFS filesystem, the test
+io/fs.t may fail on test #18. This appears to be a bug in HP-UX and no
+fix is currently available.
+
+=head2 HP-UX Kernel Parameters (maxdsiz) for Compiling Perl
+
+By default, HP-UX comes configured with a maximum data segment size of
+64MB. This is too small to correctly compile Perl with the maximum
+optimization levels. You can increase the size of the maxdsiz kernel
+parameter through the use of SAM.
+
+When using the GUI version of SAM, click on the Kernel Configuration
+icon, then the Configurable Parameters icon. Scroll down and select
+the maxdsiz line. From the Actions menu, select the Modify Configurable
+Parameter item. Insert the new formula into the Formula/Value box.
+Then follow the instructions to rebuild your kernel and reboot your
+system.
+
+In general, a value of 256MB (or "256*1024*1024") is sufficient for
+Perl to compile at maximum optimization.
+
+=head1 nss_delete core dump from op/pwent or op/grent
+
+You may get a bus error core dump from the op/pwent or op/grent
+tests. If compiled with -g you will see a stack trace much like
+the following:
+
+ #0 0xc004216c in () from /usr/lib/libc.2
+ #1 0xc00d7550 in __nss_src_state_destr () from /usr/lib/libc.2
+ #2 0xc00d7768 in __nss_src_state_destr () from /usr/lib/libc.2
+ #3 0xc00d78a8 in nss_delete () from /usr/lib/libc.2
+ #4 0xc01126d8 in endpwent () from /usr/lib/libc.2
+ #5 0xd1950 in Perl_pp_epwent () from ./perl
+ #6 0x94d3c in Perl_runops_standard () from ./perl
+ #7 0x23728 in S_run_body () from ./perl
+ #8 0x23428 in perl_run () from ./perl
+ #9 0x2005c in main () from ./perl
+
+The key here is the C<nss_delete> call. One workaround for this
+bug seems to be to create add to the file F</etc/nsswitch.conf>
+(at least) the following lines
+
+ group: files
+ passwd: files
+
+Whether you are using NIS does not matter. Amazingly enough,
+the same bug also affects Solaris.
+
+=head1 Miscellaneous
+
+HP-UX 11 Y2K patch "Y2K-1100 B.11.00.B0125 HP-UX Core OS Year 2000
+Patch Bundle" has been reported to break the io/fs test #18 which
+tests whether utime() can change timestamps. The Y2K patch seems to
+break utime() so that over NFS the timestamps do not get changed
+(on local filesystems utime() still works). This has probably been
+fixed on your system by now.
+
+=head1 AUTHOR
+
+H.Merijn Brand <h.m.brand@xs4all.nl>
+Jeff Okamoto <okamoto@corp.hp.com>
+
+With much assistance regarding shared libraries from Marc Sabatella.
+
+=head1 DATE
+
+Version 0.8.3: 2008-06-24
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlhurd.pod b/Master/tlpkg/tlperl/lib/pods/perlhurd.pod
new file mode 100644
index 00000000000..251249cbc15
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlhurd.pod
@@ -0,0 +1,54 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.hurd - Perl version 5 on Hurd
+
+=head1 DESCRIPTION
+
+If you want to use Perl on the Hurd, I recommend using the Debian
+GNU/Hurd distribution ( see http://www.debian.org/ ), even if an
+official, stable release has not yet been made. The old "gnu-0.2"
+binary distribution will most certainly have additional problems.
+
+=head2 Known Problems with Perl on Hurd
+
+The Perl test suite may still report some errors on the Hurd. The
+"lib/anydbm" and "pragma/warnings" tests will almost certainly fail.
+Both failures are not really specific to the Hurd, as indicated by the
+test suite output.
+
+The socket tests may fail if the network is not configured. You have
+to make "/hurd/pfinet" the translator for "/servers/socket/2", giving
+it the right arguments. Try "/hurd/pfinet --help" for more
+information.
+
+Here are the statistics for Perl 5.005_62 on my system:
+
+ Failed Test Status Wstat Total Fail Failed List of failed
+ -------------------------------------------------------------------------
+ lib/anydbm.t 12 1 8.33% 12
+ pragma/warnings 333 1 0.30% 215
+
+ 8 tests and 24 subtests skipped.
+ Failed 2/229 test scripts, 99.13% okay. 2/10850 subtests failed, 99.98% okay.
+
+There are quite a few systems out there that do worse!
+
+However, since I am running a very recent Hurd snapshot, in which a lot of
+bugs that were exposed by the Perl test suite have been fixed, you may
+encounter more failures. Likely candidates are: "op/stat", "lib/io_pipe",
+"lib/io_sock", "lib/io_udp" and "lib/time".
+
+In any way, if you're seeing failures beyond those mentioned in this
+document, please consider upgrading to the latest Hurd before reporting
+the failure as a bug.
+
+=head1 AUTHOR
+
+Mark Kettenis <kettenis@gnu.org>
+
+Last Updated: Fri, 29 Oct 1999 22:50:30 +0200
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlintern.pod b/Master/tlpkg/tlperl/lib/pods/perlintern.pod
new file mode 100644
index 00000000000..b26ba099c34
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlintern.pod
@@ -0,0 +1,2961 @@
+-*- buffer-read-only: t -*-
+
+!!!!!!! DO NOT EDIT THIS FILE !!!!!!!
+This file is built by ..\autodoc.pl extracting documentation from the C source
+files.
+
+=head1 NAME
+
+perlintern - autogenerated documentation of purely B<internal>
+ Perl functions
+
+=head1 DESCRIPTION
+X<internal Perl functions> X<interpreter functions>
+
+This file is the autogenerated documentation of functions in the
+Perl interpreter that are documented using Perl's internal documentation
+format but are not marked as part of the Perl API. In other words,
+B<they are not for use in extensions>!
+
+
+=head1 CV reference counts and CvOUTSIDE
+
+=over 8
+
+=item CvWEAKOUTSIDE
+X<CvWEAKOUTSIDE>
+
+Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
+CV (if any). Because pointers to anonymous sub prototypes are
+stored in C<&> pad slots, it is a possible to get a circular reference,
+with the parent pointing to the child and vice-versa. To avoid the
+ensuing memory leak, we do not increment the reference count of the CV
+pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
+has a C<&> pad slot pointing back to us. In this case, we set the
+C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
+circumstances we should decrement the refcount of the parent when freeing
+the child.
+
+There is a further complication with non-closure anonymous subs (i.e. those
+that do not refer to any lexicals outside that sub). In this case, the
+anonymous prototype is shared rather than being cloned. This has the
+consequence that the parent may be freed while there are still active
+children, eg
+
+ BEGIN { $a = sub { eval '$x' } }
+
+In this case, the BEGIN is freed immediately after execution since there
+are no active references to it: the anon sub prototype has
+C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
+CV, so it doesn't contribute to BEGIN's refcount either. When $a is
+executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
+and the freed BEGIN is accessed.
+
+To avoid this, whenever a CV and its associated pad is freed, any
+C<&> entries in the pad are explicitly removed from the pad, and if the
+refcount of the pointed-to anon sub is still positive, then that
+child's C<CvOUTSIDE> is set to point to its grandparent. This will only
+occur in the single specific case of a non-closure anon prototype
+having one or more active references (such as C<$a> above).
+
+One other thing to consider is that a CV may be merely undefined
+rather than freed, eg C<undef &foo>. In this case, its refcount may
+not have reached zero, but we still delete its pad and its C<CvROOT> etc.
+Since various children may still have their C<CvOUTSIDE> pointing at this
+undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
+the chain of lexical scopes is unbroken. For example, the following
+should print 123:
+
+ my $x = 123;
+ sub tmp { sub { eval '$x' } }
+ my $a = tmp();
+ undef &tmp;
+ print $a->();
+
+ bool CvWEAKOUTSIDE(CV *cv)
+
+=for hackers
+Found in file cv.h
+
+
+=back
+
+=head1 Functions in file pad.h
+
+
+=over 8
+
+=item CX_CURPAD_SAVE
+X<CX_CURPAD_SAVE>
+
+Save the current pad in the given context block structure.
+
+ void CX_CURPAD_SAVE(struct context)
+
+=for hackers
+Found in file pad.h
+
+=item CX_CURPAD_SV
+X<CX_CURPAD_SV>
+
+Access the SV at offset po in the saved current pad in the given
+context block structure (can be used as an lvalue).
+
+ SV * CX_CURPAD_SV(struct context, PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_BASE_SV
+X<PAD_BASE_SV>
+
+Get the value from slot C<po> in the base (DEPTH=1) pad of a padlist
+
+ SV * PAD_BASE_SV(PADLIST padlist, PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_CLONE_VARS
+X<PAD_CLONE_VARS>
+
+Clone the state variables associated with running and compiling pads.
+
+ void PAD_CLONE_VARS(PerlInterpreter *proto_perl, CLONE_PARAMS* param)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_FLAGS
+X<PAD_COMPNAME_FLAGS>
+
+Return the flags for the current compiling pad name
+at offset C<po>. Assumes a valid slot entry.
+
+ U32 PAD_COMPNAME_FLAGS(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_GEN
+X<PAD_COMPNAME_GEN>
+
+The generation number of the name at offset C<po> in the current
+compiling pad (lvalue). Note that C<SvUVX> is hijacked for this purpose.
+
+ STRLEN PAD_COMPNAME_GEN(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_GEN_set
+X<PAD_COMPNAME_GEN_set>
+
+Sets the generation number of the name at offset C<po> in the current
+ling pad (lvalue) to C<gen>. Note that C<SvUV_set> is hijacked for this purpose.
+
+ STRLEN PAD_COMPNAME_GEN_set(PADOFFSET po, int gen)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_OURSTASH
+X<PAD_COMPNAME_OURSTASH>
+
+Return the stash associated with an C<our> variable.
+Assumes the slot entry is a valid C<our> lexical.
+
+ HV * PAD_COMPNAME_OURSTASH(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_PV
+X<PAD_COMPNAME_PV>
+
+Return the name of the current compiling pad name
+at offset C<po>. Assumes a valid slot entry.
+
+ char * PAD_COMPNAME_PV(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_COMPNAME_TYPE
+X<PAD_COMPNAME_TYPE>
+
+Return the type (stash) of the current compiling pad name at offset
+C<po>. Must be a valid name. Returns null if not typed.
+
+ HV * PAD_COMPNAME_TYPE(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_DUP
+X<PAD_DUP>
+
+Clone a padlist.
+
+ void PAD_DUP(PADLIST dstpad, PADLIST srcpad, CLONE_PARAMS* param)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_RESTORE_LOCAL
+X<PAD_RESTORE_LOCAL>
+
+Restore the old pad saved into the local variable opad by PAD_SAVE_LOCAL()
+
+ void PAD_RESTORE_LOCAL(PAD *opad)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SAVE_LOCAL
+X<PAD_SAVE_LOCAL>
+
+Save the current pad to the local variable opad, then make the
+current pad equal to npad
+
+ void PAD_SAVE_LOCAL(PAD *opad, PAD *npad)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SAVE_SETNULLPAD
+X<PAD_SAVE_SETNULLPAD>
+
+Save the current pad then set it to null.
+
+ void PAD_SAVE_SETNULLPAD()
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SETSV
+X<PAD_SETSV>
+
+Set the slot at offset C<po> in the current pad to C<sv>
+
+ SV * PAD_SETSV(PADOFFSET po, SV* sv)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SET_CUR
+X<PAD_SET_CUR>
+
+Set the current pad to be pad C<n> in the padlist, saving
+the previous current pad. NB currently this macro expands to a string too
+long for some compilers, so it's best to replace it with
+
+ SAVECOMPPAD();
+ PAD_SET_CUR_NOSAVE(padlist,n);
+
+
+ void PAD_SET_CUR(PADLIST padlist, I32 n)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SET_CUR_NOSAVE
+X<PAD_SET_CUR_NOSAVE>
+
+like PAD_SET_CUR, but without the save
+
+ void PAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SV
+X<PAD_SV>
+
+Get the value at offset C<po> in the current pad
+
+ void PAD_SV(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item PAD_SVl
+X<PAD_SVl>
+
+Lightweight and lvalue version of C<PAD_SV>.
+Get or set the value at offset C<po> in the current pad.
+Unlike C<PAD_SV>, does not print diagnostics with -DX.
+For internal use only.
+
+ SV * PAD_SVl(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+=item SAVECLEARSV
+X<SAVECLEARSV>
+
+Clear the pointed to pad value on scope exit. (i.e. the runtime action of 'my')
+
+ void SAVECLEARSV(SV **svp)
+
+=for hackers
+Found in file pad.h
+
+=item SAVECOMPPAD
+X<SAVECOMPPAD>
+
+save PL_comppad and PL_curpad
+
+
+
+
+
+ void SAVECOMPPAD()
+
+=for hackers
+Found in file pad.h
+
+=item SAVEPADSV
+X<SAVEPADSV>
+
+Save a pad slot (used to restore after an iteration)
+
+XXX DAPM it would make more sense to make the arg a PADOFFSET
+ void SAVEPADSV(PADOFFSET po)
+
+=for hackers
+Found in file pad.h
+
+
+=back
+
+=head1 Functions in file pp_ctl.c
+
+
+=over 8
+
+=item docatch
+X<docatch>
+
+Check for the cases 0 or 3 of cur_env.je_ret, only used inside an eval context.
+
+0 is used as continue inside eval,
+
+3 is used for a die caught by an inner eval - continue inner loop
+
+See cop.h: je_mustcatch, when set at any runlevel to TRUE, means eval ops must
+establish a local jmpenv to handle exception traps.
+
+ OP* docatch(OP *o)
+
+=for hackers
+Found in file pp_ctl.c
+
+
+=back
+
+=head1 GV Functions
+
+=over 8
+
+=item gv_try_downgrade
+X<gv_try_downgrade>
+
+If the typeglob C<gv> can be expressed more succinctly, by having
+something other than a real GV in its place in the stash, replace it
+with the optimised form. Basic requirements for this are that C<gv>
+is a real typeglob, is sufficiently ordinary, and is only referenced
+from its package. This function is meant to be used when a GV has been
+looked up in part to see what was there, causing upgrading, but based
+on what was found it turns out that the real GV isn't required after all.
+
+If C<gv> is a completely empty typeglob, it is deleted from the stash.
+
+If C<gv> is a typeglob containing only a sufficiently-ordinary constant
+sub, the typeglob is replaced with a scalar-reference placeholder that
+more compactly represents the same thing.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void gv_try_downgrade(GV* gv)
+
+=for hackers
+Found in file gv.c
+
+=item is_gv_magical_sv
+X<is_gv_magical_sv>
+
+Returns C<TRUE> if given the name of a magical GV.
+
+Currently only useful internally when determining if a GV should be
+created even in rvalue contexts.
+
+C<flags> is not used at present but available for future extension to
+allow selecting particular classes of magical variable.
+
+Currently assumes that C<name> is NUL terminated (as well as len being valid).
+This assumption is met by all callers within the perl core, which all pass
+pointers returned by SvPV.
+
+ bool is_gv_magical_sv(SV *const name_sv, U32 flags)
+
+=for hackers
+Found in file gv.c
+
+
+=back
+
+=head1 Hash Manipulation Functions
+
+=over 8
+
+=item refcounted_he_chain_2hv
+X<refcounted_he_chain_2hv>
+
+Generates and returns a C<HV *> by walking up the tree starting at the passed
+in C<struct refcounted_he *>.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ HV * refcounted_he_chain_2hv(const struct refcounted_he *c)
+
+=for hackers
+Found in file hv.c
+
+=item refcounted_he_free
+X<refcounted_he_free>
+
+Decrements the reference count of the passed in C<struct refcounted_he *>
+by one. If the reference count reaches zero the structure's memory is freed,
+and C<refcounted_he_free> iterates onto the parent node.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ void refcounted_he_free(struct refcounted_he *he)
+
+=for hackers
+Found in file hv.c
+
+=item refcounted_he_new
+X<refcounted_he_new>
+
+Creates a new C<struct refcounted_he>. As S<key> is copied, and value is
+stored in a compact form, all references remain the property of the caller.
+The C<struct refcounted_he> is returned with a reference count of 1.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ struct refcounted_he * refcounted_he_new(struct refcounted_he *const parent, SV *const key, SV *const value)
+
+=for hackers
+Found in file hv.c
+
+
+=back
+
+=head1 IO Functions
+
+=over 8
+
+=item start_glob
+X<start_glob>
+
+Function called by C<do_readline> to spawn a glob (or do the glob inside
+perl on VMS). This code used to be inline, but now perl uses C<File::Glob>
+this glob starter is only used by miniperl during the build process.
+Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ PerlIO* start_glob(SV *tmpglob, IO *io)
+
+=for hackers
+Found in file doio.c
+
+
+=back
+
+=head1 Magical Functions
+
+=over 8
+
+=item magic_clearhint
+X<magic_clearhint>
+
+Triggered by a delete from %^H, records the key to
+C<PL_compiling.cop_hints_hash>.
+
+ int magic_clearhint(SV* sv, MAGIC* mg)
+
+=for hackers
+Found in file mg.c
+
+=item magic_clearhints
+X<magic_clearhints>
+
+Triggered by clearing %^H, resets C<PL_compiling.cop_hints_hash>.
+
+ int magic_clearhints(SV* sv, MAGIC* mg)
+
+=for hackers
+Found in file mg.c
+
+=item magic_sethint
+X<magic_sethint>
+
+Triggered by a store to %^H, records the key/value pair to
+C<PL_compiling.cop_hints_hash>. It is assumed that hints aren't storing
+anything that would need a deep copy. Maybe we should warn if we find a
+reference.
+
+ int magic_sethint(SV* sv, MAGIC* mg)
+
+=for hackers
+Found in file mg.c
+
+=item mg_localize
+X<mg_localize>
+
+Copy some of the magic from an existing SV to new localized version of that
+SV. Container magic (eg %ENV, $1, tie) gets copied, value magic doesn't (eg
+taint, pos).
+
+If setmagic is false then no set magic will be called on the new (empty) SV.
+This typically means that assignment will soon follow (e.g. 'local $x = $y'),
+and that will handle the magic.
+
+ void mg_localize(SV* sv, SV* nsv, bool setmagic)
+
+=for hackers
+Found in file mg.c
+
+
+=back
+
+=head1 MRO Functions
+
+=over 8
+
+=item mro_get_linear_isa_dfs
+X<mro_get_linear_isa_dfs>
+
+Returns the Depth-First Search linearization of @ISA
+the given stash. The return value is a read-only AV*.
+C<level> should be 0 (it is used internally in this
+function's recursion).
+
+You are responsible for C<SvREFCNT_inc()> on the
+return value if you plan to store it anywhere
+semi-permanently (otherwise it might be deleted
+out from under you the next time the cache is
+invalidated).
+
+ AV* mro_get_linear_isa_dfs(HV* stash, U32 level)
+
+=for hackers
+Found in file mro.c
+
+=item mro_isa_changed_in
+X<mro_isa_changed_in>
+
+Takes the necessary steps (cache invalidations, mostly)
+when the @ISA of the given package has changed. Invoked
+by the C<setisa> magic, should not need to invoke directly.
+
+ void mro_isa_changed_in(HV* stash)
+
+=for hackers
+Found in file mro.c
+
+
+=back
+
+=head1 Pad Data Structures
+
+=over 8
+
+=item CvPADLIST
+X<CvPADLIST>
+
+CV's can have CvPADLIST(cv) set to point to an AV.
+
+For these purposes "forms" are a kind-of CV, eval""s are too (except they're
+not callable at will and are always thrown away after the eval"" is done
+executing). Require'd files are simply evals without any outer lexical
+scope.
+
+XSUBs don't have CvPADLIST set - dXSTARG fetches values from PL_curpad,
+but that is really the callers pad (a slot of which is allocated by
+every entersub).
+
+The CvPADLIST AV has does not have AvREAL set, so REFCNT of component items
+is managed "manual" (mostly in pad.c) rather than normal av.c rules.
+The items in the AV are not SVs as for a normal AV, but other AVs:
+
+0'th Entry of the CvPADLIST is an AV which represents the "names" or rather
+the "static type information" for lexicals.
+
+The CvDEPTH'th entry of CvPADLIST AV is an AV which is the stack frame at that
+depth of recursion into the CV.
+The 0'th slot of a frame AV is an AV which is @_.
+other entries are storage for variables and op targets.
+
+During compilation:
+C<PL_comppad_name> is set to the names AV.
+C<PL_comppad> is set to the frame AV for the frame CvDEPTH == 1.
+C<PL_curpad> is set to the body of the frame AV (i.e. AvARRAY(PL_comppad)).
+
+During execution, C<PL_comppad> and C<PL_curpad> refer to the live
+frame of the currently executing sub.
+
+Iterating over the names AV iterates over all possible pad
+items. Pad slots that are SVs_PADTMP (targets/GVs/constants) end up having
+&PL_sv_undef "names" (see pad_alloc()).
+
+Only my/our variable (SVs_PADMY/SVs_PADOUR) slots get valid names.
+The rest are op targets/GVs/constants which are statically allocated
+or resolved at compile time. These don't have names by which they
+can be looked up from Perl code at run time through eval"" like
+my/our variables can be. Since they can't be looked up by "name"
+but only by their index allocated at compile time (which is usually
+in PL_op->op_targ), wasting a name SV for them doesn't make sense.
+
+The SVs in the names AV have their PV being the name of the variable.
+xlow+1..xhigh inclusive in the NV union is a range of cop_seq numbers for
+which the name is valid. For typed lexicals name SV is SVt_PVMG and SvSTASH
+points at the type. For C<our> lexicals, the type is also SVt_PVMG, with the
+SvOURSTASH slot pointing at the stash of the associated global (so that
+duplicate C<our> declarations in the same package can be detected). SvUVX is
+sometimes hijacked to store the generation number during compilation.
+
+If SvFAKE is set on the name SV, then that slot in the frame AV is
+a REFCNT'ed reference to a lexical from "outside". In this case,
+the name SV does not use xlow and xhigh to store a cop_seq range, since it is
+in scope throughout. Instead xhigh stores some flags containing info about
+the real lexical (is it declared in an anon, and is it capable of being
+instantiated multiple times?), and for fake ANONs, xlow contains the index
+within the parent's pad where the lexical's value is stored, to make
+cloning quicker.
+
+If the 'name' is '&' the corresponding entry in frame AV
+is a CV representing a possible closure.
+(SvFAKE and name of '&' is not a meaningful combination currently but could
+become so if C<my sub foo {}> is implemented.)
+
+Note that formats are treated as anon subs, and are cloned each time
+write is called (if necessary).
+
+The flag SVs_PADSTALE is cleared on lexicals each time the my() is executed,
+and set on scope exit. This allows the 'Variable $x is not available' warning
+to be generated in evals, such as
+
+ { my $x = 1; sub f { eval '$x'} } f();
+
+For state vars, SVs_PADSTALE is overloaded to mean 'not yet initialised'
+
+ AV * CvPADLIST(CV *cv)
+
+=for hackers
+Found in file pad.c
+
+=item cv_clone
+X<cv_clone>
+
+Clone a CV: make a new CV which points to the same code etc, but which
+has a newly-created pad built by copying the prototype pad and capturing
+any outer lexicals.
+
+ CV* cv_clone(CV* proto)
+
+=for hackers
+Found in file pad.c
+
+=item cv_dump
+X<cv_dump>
+
+dump the contents of a CV
+
+ void cv_dump(const CV *cv, const char *title)
+
+=for hackers
+Found in file pad.c
+
+=item do_dump_pad
+X<do_dump_pad>
+
+Dump the contents of a padlist
+
+ void do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full)
+
+=for hackers
+Found in file pad.c
+
+=item intro_my
+X<intro_my>
+
+"Introduce" my variables to visible status.
+
+ U32 intro_my()
+
+=for hackers
+Found in file pad.c
+
+=item pad_add_anon
+X<pad_add_anon>
+
+Add an anon code entry to the current compiling pad
+
+ PADOFFSET pad_add_anon(SV* sv, OPCODE op_type)
+
+=for hackers
+Found in file pad.c
+
+=item pad_add_name
+X<pad_add_name>
+
+Create a new name and associated PADMY SV in the current pad; return the
+offset.
+If C<typestash> is valid, the name is for a typed lexical; set the
+name's stash to that value.
+If C<ourstash> is valid, it's an our lexical, set the name's
+SvOURSTASH to that value
+
+If fake, it means we're cloning an existing entry
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ PADOFFSET pad_add_name(const char *name, const STRLEN len, const U32 flags, HV *typestash, HV *ourstash)
+
+=for hackers
+Found in file pad.c
+
+=item pad_alloc
+X<pad_alloc>
+
+Allocate a new my or tmp pad entry. For a my, simply push a null SV onto
+the end of PL_comppad, but for a tmp, scan the pad from PL_padix upwards
+for a slot which has no name and no active value.
+
+ PADOFFSET pad_alloc(I32 optype, U32 tmptype)
+
+=for hackers
+Found in file pad.c
+
+=item pad_block_start
+X<pad_block_start>
+
+Update the pad compilation state variables on entry to a new block
+
+ void pad_block_start(int full)
+
+=for hackers
+Found in file pad.c
+
+=item pad_check_dup
+X<pad_check_dup>
+
+Check for duplicate declarations: report any of:
+ * a my in the current scope with the same name;
+ * an our (anywhere in the pad) with the same name and the same stash
+ as C<ourstash>
+C<is_our> indicates that the name to check is an 'our' declaration
+
+ void pad_check_dup(SV *name, const U32 flags, const HV *ourstash)
+
+=for hackers
+Found in file pad.c
+
+=item pad_findlex
+X<pad_findlex>
+
+Find a named lexical anywhere in a chain of nested pads. Add fake entries
+in the inner pads if it's found in an outer one.
+
+Returns the offset in the bottom pad of the lex or the fake lex.
+cv is the CV in which to start the search, and seq is the current cop_seq
+to match against. If warn is true, print appropriate warnings. The out_*
+vars return values, and so are pointers to where the returned values
+should be stored. out_capture, if non-null, requests that the innermost
+instance of the lexical is captured; out_name_sv is set to the innermost
+matched namesv or fake namesv; out_flags returns the flags normally
+associated with the IVX field of a fake namesv.
+
+Note that pad_findlex() is recursive; it recurses up the chain of CVs,
+then comes back down, adding fake entries as it goes. It has to be this way
+because fake namesvs in anon protoypes have to store in xlow the index into
+the parent pad.
+
+ PADOFFSET pad_findlex(const char *name, const CV* cv, U32 seq, int warn, SV** out_capture, SV** out_name_sv, int *out_flags)
+
+=for hackers
+Found in file pad.c
+
+=item pad_fixup_inner_anons
+X<pad_fixup_inner_anons>
+
+For any anon CVs in the pad, change CvOUTSIDE of that CV from
+old_cv to new_cv if necessary. Needed when a newly-compiled CV has to be
+moved to a pre-existing CV struct.
+
+ void pad_fixup_inner_anons(PADLIST *padlist, CV *old_cv, CV *new_cv)
+
+=for hackers
+Found in file pad.c
+
+=item pad_free
+X<pad_free>
+
+Free the SV at offset po in the current pad.
+
+ void pad_free(PADOFFSET po)
+
+=for hackers
+Found in file pad.c
+
+=item pad_leavemy
+X<pad_leavemy>
+
+Cleanup at end of scope during compilation: set the max seq number for
+lexicals in this scope and warn of any lexicals that never got introduced.
+
+ void pad_leavemy()
+
+=for hackers
+Found in file pad.c
+
+=item pad_new
+X<pad_new>
+
+Create a new compiling padlist, saving and updating the various global
+vars at the same time as creating the pad itself. The following flags
+can be OR'ed together:
+
+ padnew_CLONE this pad is for a cloned CV
+ padnew_SAVE save old globals
+ padnew_SAVESUB also save extra stuff for start of sub
+
+ PADLIST* pad_new(int flags)
+
+=for hackers
+Found in file pad.c
+
+=item pad_push
+X<pad_push>
+
+Push a new pad frame onto the padlist, unless there's already a pad at
+this depth, in which case don't bother creating a new one. Then give
+the new pad an @_ in slot zero.
+
+ void pad_push(PADLIST *padlist, int depth)
+
+=for hackers
+Found in file pad.c
+
+=item pad_reset
+X<pad_reset>
+
+Mark all the current temporaries for reuse
+
+ void pad_reset()
+
+=for hackers
+Found in file pad.c
+
+=item pad_setsv
+X<pad_setsv>
+
+Set the entry at offset po in the current pad to sv.
+Use the macro PAD_SETSV() rather than calling this function directly.
+
+ void pad_setsv(PADOFFSET po, SV* sv)
+
+=for hackers
+Found in file pad.c
+
+=item pad_swipe
+X<pad_swipe>
+
+Abandon the tmp in the current pad at offset po and replace with a
+new one.
+
+ void pad_swipe(PADOFFSET po, bool refadjust)
+
+=for hackers
+Found in file pad.c
+
+=item pad_tidy
+X<pad_tidy>
+
+Tidy up a pad after we've finished compiling it:
+ * remove most stuff from the pads of anonsub prototypes;
+ * give it a @_;
+ * mark tmps as such.
+
+ void pad_tidy(padtidy_type type)
+
+=for hackers
+Found in file pad.c
+
+=item pad_undef
+X<pad_undef>
+
+Free the padlist associated with a CV.
+If parts of it happen to be current, we null the relevant
+PL_*pad* global vars so that we don't have any dangling references left.
+We also repoint the CvOUTSIDE of any about-to-be-orphaned
+inner subs to the outer of this cv.
+
+(This function should really be called pad_free, but the name was already
+taken)
+
+ void pad_undef(CV* cv)
+
+=for hackers
+Found in file pad.c
+
+
+=back
+
+=head1 Per-Interpreter Variables
+
+=over 8
+
+=item PL_DBsingle
+X<PL_DBsingle>
+
+When Perl is run in debugging mode, with the B<-d> switch, this SV is a
+boolean which indicates whether subs are being single-stepped.
+Single-stepping is automatically turned on after every step. This is the C
+variable which corresponds to Perl's $DB::single variable. See
+C<PL_DBsub>.
+
+ SV * PL_DBsingle
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_DBsub
+X<PL_DBsub>
+
+When Perl is run in debugging mode, with the B<-d> switch, this GV contains
+the SV which holds the name of the sub being debugged. This is the C
+variable which corresponds to Perl's $DB::sub variable. See
+C<PL_DBsingle>.
+
+ GV * PL_DBsub
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_DBtrace
+X<PL_DBtrace>
+
+Trace variable used when Perl is run in debugging mode, with the B<-d>
+switch. This is the C variable which corresponds to Perl's $DB::trace
+variable. See C<PL_DBsingle>.
+
+ SV * PL_DBtrace
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_dowarn
+X<PL_dowarn>
+
+The C variable which corresponds to Perl's $^W warning variable.
+
+ bool PL_dowarn
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_last_in_gv
+X<PL_last_in_gv>
+
+The GV which was last used for a filehandle input operation. (C<< <FH> >>)
+
+ GV* PL_last_in_gv
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_ofsgv
+X<PL_ofsgv>
+
+The glob containing the output field separator - C<*,> in Perl space.
+
+ GV* PL_ofsgv
+
+=for hackers
+Found in file intrpvar.h
+
+=item PL_rs
+X<PL_rs>
+
+The input record separator - C<$/> in Perl space.
+
+ SV* PL_rs
+
+=for hackers
+Found in file intrpvar.h
+
+
+=back
+
+=head1 Stack Manipulation Macros
+
+=over 8
+
+=item djSP
+X<djSP>
+
+Declare Just C<SP>. This is actually identical to C<dSP>, and declares
+a local copy of perl's stack pointer, available via the C<SP> macro.
+See C<SP>. (Available for backward source code compatibility with the
+old (Perl 5.005) thread model.)
+
+ djSP;
+
+=for hackers
+Found in file pp.h
+
+=item LVRET
+X<LVRET>
+
+True if this op will be the return value of an lvalue subroutine
+
+=for hackers
+Found in file pp.h
+
+
+=back
+
+=head1 SV Manipulation Functions
+
+=over 8
+
+=item sv_add_arena
+X<sv_add_arena>
+
+Given a chunk of memory, link it to the head of the list of arenas,
+and split it into a list of free SVs.
+
+ void sv_add_arena(char *const ptr, const U32 size, const U32 flags)
+
+=for hackers
+Found in file sv.c
+
+=item sv_clean_all
+X<sv_clean_all>
+
+Decrement the refcnt of each remaining SV, possibly triggering a
+cleanup. This function may have to be called multiple times to free
+SVs which are in complex self-referential hierarchies.
+
+ I32 sv_clean_all()
+
+=for hackers
+Found in file sv.c
+
+=item sv_clean_objs
+X<sv_clean_objs>
+
+Attempt to destroy all objects not yet freed
+
+ void sv_clean_objs()
+
+=for hackers
+Found in file sv.c
+
+=item sv_free_arenas
+X<sv_free_arenas>
+
+Deallocate the memory used by all arenas. Note that all the individual SV
+heads and bodies within the arenas must already have been freed.
+
+ void sv_free_arenas()
+
+=for hackers
+Found in file sv.c
+
+
+=back
+
+=head1 SV-Body Allocation
+
+=over 8
+
+=item sv_2num
+X<sv_2num>
+
+Return an SV with the numeric value of the source SV, doing any necessary
+reference or overload conversion. You must use the C<SvNUM(sv)> macro to
+access this function.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ SV* sv_2num(SV *const sv)
+
+=for hackers
+Found in file sv.c
+
+
+=back
+
+=head1 Unicode Support
+
+=over 8
+
+=item find_uninit_var
+X<find_uninit_var>
+
+Find the name of the undefined variable (if any) that caused the operator o
+to issue a "Use of uninitialized value" warning.
+If match is true, only return a name if it's value matches uninit_sv.
+So roughly speaking, if a unary operator (such as OP_COS) generates a
+warning, then following the direct child of the op may yield an
+OP_PADSV or OP_GV that gives the name of the undefined variable. On the
+other hand, with OP_ADD there are two branches to follow, so we only print
+the variable name if we get an exact match.
+
+The name is returned as a mortal SV.
+
+Assumes that PL_op is the op that originally triggered the error, and that
+PL_comppad/PL_curpad points to the currently executing pad.
+
+NOTE: this function is experimental and may change or be
+removed without notice.
+
+ SV* find_uninit_var(const OP *const obase, const SV *const uninit_sv, bool top)
+
+=for hackers
+Found in file sv.c
+
+=item report_uninit
+X<report_uninit>
+
+Print appropriate "Use of uninitialized variable" warning
+
+ void report_uninit(const SV *uninit_sv)
+
+=for hackers
+Found in file sv.c
+
+
+=back
+
+=head1 Undocumented functions
+
+These functions are currently undocumented:
+
+=over
+
+=item F0convert
+X<F0convert>
+
+=item Slab_to_rw
+X<Slab_to_rw>
+
+=item add_data
+X<add_data>
+
+=item add_utf16_textfilter
+X<add_utf16_textfilter>
+
+=item addmad
+X<addmad>
+
+=item allocmy
+X<allocmy>
+
+=item amagic_cmp
+X<amagic_cmp>
+
+=item amagic_cmp_locale
+X<amagic_cmp_locale>
+
+=item amagic_i_ncmp
+X<amagic_i_ncmp>
+
+=item amagic_ncmp
+X<amagic_ncmp>
+
+=item anonymise_cv
+X<anonymise_cv>
+
+=item ao
+X<ao>
+
+=item append_elem
+X<append_elem>
+
+=item append_list
+X<append_list>
+
+=item append_madprops
+X<append_madprops>
+
+=item apply
+X<apply>
+
+=item apply_attrs
+X<apply_attrs>
+
+=item apply_attrs_my
+X<apply_attrs_my>
+
+=item av_reify
+X<av_reify>
+
+=item bad_type
+X<bad_type>
+
+=item bind_match
+X<bind_match>
+
+=item block_end
+X<block_end>
+
+=item block_start
+X<block_start>
+
+=item boot_core_PerlIO
+X<boot_core_PerlIO>
+
+=item boot_core_UNIVERSAL
+X<boot_core_UNIVERSAL>
+
+=item boot_core_mro
+X<boot_core_mro>
+
+=item bytes_to_uni
+X<bytes_to_uni>
+
+=item cando
+X<cando>
+
+=item check_type_and_open
+X<check_type_and_open>
+
+=item check_uni
+X<check_uni>
+
+=item checkcomma
+X<checkcomma>
+
+=item checkposixcc
+X<checkposixcc>
+
+=item ck_anoncode
+X<ck_anoncode>
+
+=item ck_bitop
+X<ck_bitop>
+
+=item ck_concat
+X<ck_concat>
+
+=item ck_defined
+X<ck_defined>
+
+=item ck_delete
+X<ck_delete>
+
+=item ck_die
+X<ck_die>
+
+=item ck_each
+X<ck_each>
+
+=item ck_eof
+X<ck_eof>
+
+=item ck_eval
+X<ck_eval>
+
+=item ck_exec
+X<ck_exec>
+
+=item ck_exists
+X<ck_exists>
+
+=item ck_exit
+X<ck_exit>
+
+=item ck_ftst
+X<ck_ftst>
+
+=item ck_fun
+X<ck_fun>
+
+=item ck_glob
+X<ck_glob>
+
+=item ck_grep
+X<ck_grep>
+
+=item ck_index
+X<ck_index>
+
+=item ck_join
+X<ck_join>
+
+=item ck_lfun
+X<ck_lfun>
+
+=item ck_listiob
+X<ck_listiob>
+
+=item ck_match
+X<ck_match>
+
+=item ck_method
+X<ck_method>
+
+=item ck_null
+X<ck_null>
+
+=item ck_open
+X<ck_open>
+
+=item ck_readline
+X<ck_readline>
+
+=item ck_repeat
+X<ck_repeat>
+
+=item ck_require
+X<ck_require>
+
+=item ck_return
+X<ck_return>
+
+=item ck_rfun
+X<ck_rfun>
+
+=item ck_rvconst
+X<ck_rvconst>
+
+=item ck_sassign
+X<ck_sassign>
+
+=item ck_select
+X<ck_select>
+
+=item ck_shift
+X<ck_shift>
+
+=item ck_sort
+X<ck_sort>
+
+=item ck_spair
+X<ck_spair>
+
+=item ck_split
+X<ck_split>
+
+=item ck_subr
+X<ck_subr>
+
+=item ck_substr
+X<ck_substr>
+
+=item ck_svconst
+X<ck_svconst>
+
+=item ck_trunc
+X<ck_trunc>
+
+=item ck_unpack
+X<ck_unpack>
+
+=item ckwarn_common
+X<ckwarn_common>
+
+=item cl_and
+X<cl_and>
+
+=item cl_anything
+X<cl_anything>
+
+=item cl_init
+X<cl_init>
+
+=item cl_init_zero
+X<cl_init_zero>
+
+=item cl_is_anything
+X<cl_is_anything>
+
+=item cl_or
+X<cl_or>
+
+=item clear_placeholders
+X<clear_placeholders>
+
+=item closest_cop
+X<closest_cop>
+
+=item convert
+X<convert>
+
+=item cop_free
+X<cop_free>
+
+=item cr_textfilter
+X<cr_textfilter>
+
+=item create_eval_scope
+X<create_eval_scope>
+
+=item curmad
+X<curmad>
+
+=item cv_ckproto_len
+X<cv_ckproto_len>
+
+=item deb_curcv
+X<deb_curcv>
+
+=item deb_stack_all
+X<deb_stack_all>
+
+=item deb_stack_n
+X<deb_stack_n>
+
+=item debprof
+X<debprof>
+
+=item debug_start_match
+X<debug_start_match>
+
+=item del_sv
+X<del_sv>
+
+=item delete_eval_scope
+X<delete_eval_scope>
+
+=item deprecate_commaless_var_list
+X<deprecate_commaless_var_list>
+
+=item destroy_matcher
+X<destroy_matcher>
+
+=item die_where
+X<die_where>
+
+=item div128
+X<div128>
+
+=item do_aexec
+X<do_aexec>
+
+=item do_aexec5
+X<do_aexec5>
+
+=item do_chomp
+X<do_chomp>
+
+=item do_chop
+X<do_chop>
+
+=item do_delete_local
+X<do_delete_local>
+
+=item do_eof
+X<do_eof>
+
+=item do_exec
+X<do_exec>
+
+=item do_exec3
+X<do_exec3>
+
+=item do_execfree
+X<do_execfree>
+
+=item do_ipcctl
+X<do_ipcctl>
+
+=item do_ipcget
+X<do_ipcget>
+
+=item do_kv
+X<do_kv>
+
+=item do_msgrcv
+X<do_msgrcv>
+
+=item do_msgsnd
+X<do_msgsnd>
+
+=item do_oddball
+X<do_oddball>
+
+=item do_op_xmldump
+X<do_op_xmldump>
+
+=item do_pmop_xmldump
+X<do_pmop_xmldump>
+
+=item do_print
+X<do_print>
+
+=item do_readline
+X<do_readline>
+
+=item do_seek
+X<do_seek>
+
+=item do_semop
+X<do_semop>
+
+=item do_shmio
+X<do_shmio>
+
+=item do_smartmatch
+X<do_smartmatch>
+
+=item do_sysseek
+X<do_sysseek>
+
+=item do_tell
+X<do_tell>
+
+=item do_trans
+X<do_trans>
+
+=item do_trans_complex
+X<do_trans_complex>
+
+=item do_trans_complex_utf8
+X<do_trans_complex_utf8>
+
+=item do_trans_count
+X<do_trans_count>
+
+=item do_trans_count_utf8
+X<do_trans_count_utf8>
+
+=item do_trans_simple
+X<do_trans_simple>
+
+=item do_trans_simple_utf8
+X<do_trans_simple_utf8>
+
+=item do_vecget
+X<do_vecget>
+
+=item do_vecset
+X<do_vecset>
+
+=item do_vop
+X<do_vop>
+
+=item doeval
+X<doeval>
+
+=item dofile
+X<dofile>
+
+=item dofindlabel
+X<dofindlabel>
+
+=item doform
+X<doform>
+
+=item dooneliner
+X<dooneliner>
+
+=item doopen_pm
+X<doopen_pm>
+
+=item doparseform
+X<doparseform>
+
+=item dopoptoeval
+X<dopoptoeval>
+
+=item dopoptogiven
+X<dopoptogiven>
+
+=item dopoptolabel
+X<dopoptolabel>
+
+=item dopoptoloop
+X<dopoptoloop>
+
+=item dopoptosub_at
+X<dopoptosub_at>
+
+=item dopoptowhen
+X<dopoptowhen>
+
+=item dump_all_perl
+X<dump_all_perl>
+
+=item dump_exec_pos
+X<dump_exec_pos>
+
+=item dump_packsubs_perl
+X<dump_packsubs_perl>
+
+=item dump_sub_perl
+X<dump_sub_perl>
+
+=item dump_sv_child
+X<dump_sv_child>
+
+=item dump_trie
+X<dump_trie>
+
+=item dump_trie_interim_list
+X<dump_trie_interim_list>
+
+=item dump_trie_interim_table
+X<dump_trie_interim_table>
+
+=item dumpuntil
+X<dumpuntil>
+
+=item dup_attrlist
+X<dup_attrlist>
+
+=item emulate_cop_io
+X<emulate_cop_io>
+
+=item exec_failed
+X<exec_failed>
+
+=item expect_number
+X<expect_number>
+
+=item feature_is_enabled
+X<feature_is_enabled>
+
+=item filter_gets
+X<filter_gets>
+
+=item find_and_forget_pmops
+X<find_and_forget_pmops>
+
+=item find_array_subscript
+X<find_array_subscript>
+
+=item find_beginning
+X<find_beginning>
+
+=item find_byclass
+X<find_byclass>
+
+=item find_hash_subscript
+X<find_hash_subscript>
+
+=item find_in_my_stash
+X<find_in_my_stash>
+
+=item find_script
+X<find_script>
+
+=item first_symbol
+X<first_symbol>
+
+=item fold_constants
+X<fold_constants>
+
+=item forbid_setid
+X<forbid_setid>
+
+=item force_ident
+X<force_ident>
+
+=item force_list
+X<force_list>
+
+=item force_next
+X<force_next>
+
+=item force_strict_version
+X<force_strict_version>
+
+=item force_version
+X<force_version>
+
+=item force_word
+X<force_word>
+
+=item forget_pmop
+X<forget_pmop>
+
+=item free_tied_hv_pool
+X<free_tied_hv_pool>
+
+=item gen_constant_list
+X<gen_constant_list>
+
+=item get_arena
+X<get_arena>
+
+=item get_aux_mg
+X<get_aux_mg>
+
+=item get_db_sub
+X<get_db_sub>
+
+=item get_debug_opts
+X<get_debug_opts>
+
+=item get_hash_seed
+X<get_hash_seed>
+
+=item get_isa_hash
+X<get_isa_hash>
+
+=item get_no_modify
+X<get_no_modify>
+
+=item get_num
+X<get_num>
+
+=item get_opargs
+X<get_opargs>
+
+=item get_re_arg
+X<get_re_arg>
+
+=item getenv_len
+X<getenv_len>
+
+=item glob_2number
+X<glob_2number>
+
+=item glob_assign_glob
+X<glob_assign_glob>
+
+=item glob_assign_ref
+X<glob_assign_ref>
+
+=item group_end
+X<group_end>
+
+=item gv_ename
+X<gv_ename>
+
+=item gv_get_super_pkg
+X<gv_get_super_pkg>
+
+=item gv_init_sv
+X<gv_init_sv>
+
+=item hfreeentries
+X<hfreeentries>
+
+=item hsplit
+X<hsplit>
+
+=item hv_auxinit
+X<hv_auxinit>
+
+=item hv_backreferences_p
+X<hv_backreferences_p>
+
+=item hv_copy_hints_hv
+X<hv_copy_hints_hv>
+
+=item hv_delete_common
+X<hv_delete_common>
+
+=item hv_kill_backrefs
+X<hv_kill_backrefs>
+
+=item hv_magic_check
+X<hv_magic_check>
+
+=item hv_notallowed
+X<hv_notallowed>
+
+=item incline
+X<incline>
+
+=item incpush
+X<incpush>
+
+=item incpush_if_exists
+X<incpush_if_exists>
+
+=item incpush_use_sep
+X<incpush_use_sep>
+
+=item ingroup
+X<ingroup>
+
+=item init_argv_symbols
+X<init_argv_symbols>
+
+=item init_dbargs
+X<init_dbargs>
+
+=item init_debugger
+X<init_debugger>
+
+=item init_ids
+X<init_ids>
+
+=item init_interp
+X<init_interp>
+
+=item init_main_stash
+X<init_main_stash>
+
+=item init_perllib
+X<init_perllib>
+
+=item init_postdump_symbols
+X<init_postdump_symbols>
+
+=item init_predump_symbols
+X<init_predump_symbols>
+
+=item intuit_method
+X<intuit_method>
+
+=item intuit_more
+X<intuit_more>
+
+=item invert
+X<invert>
+
+=item io_close
+X<io_close>
+
+=item is_an_int
+X<is_an_int>
+
+=item is_handle_constructor
+X<is_handle_constructor>
+
+=item is_inplace_av
+X<is_inplace_av>
+
+=item is_list_assignment
+X<is_list_assignment>
+
+=item is_utf8_X_L
+X<is_utf8_X_L>
+
+=item is_utf8_X_LV
+X<is_utf8_X_LV>
+
+=item is_utf8_X_LVT
+X<is_utf8_X_LVT>
+
+=item is_utf8_X_LV_LVT_V
+X<is_utf8_X_LV_LVT_V>
+
+=item is_utf8_X_T
+X<is_utf8_X_T>
+
+=item is_utf8_X_V
+X<is_utf8_X_V>
+
+=item is_utf8_X_begin
+X<is_utf8_X_begin>
+
+=item is_utf8_X_extend
+X<is_utf8_X_extend>
+
+=item is_utf8_X_non_hangul
+X<is_utf8_X_non_hangul>
+
+=item is_utf8_X_prepend
+X<is_utf8_X_prepend>
+
+=item is_utf8_char_slow
+X<is_utf8_char_slow>
+
+=item is_utf8_common
+X<is_utf8_common>
+
+=item isa_lookup
+X<isa_lookup>
+
+=item jmaybe
+X<jmaybe>
+
+=item join_exact
+X<join_exact>
+
+=item keyword
+X<keyword>
+
+=item keyword_plugin_standard
+X<keyword_plugin_standard>
+
+=item lex_end
+X<lex_end>
+
+=item lex_start
+X<lex_start>
+
+=item linklist
+X<linklist>
+
+=item list
+X<list>
+
+=item listkids
+X<listkids>
+
+=item localize
+X<localize>
+
+=item looks_like_bool
+X<looks_like_bool>
+
+=item lop
+X<lop>
+
+=item mad_free
+X<mad_free>
+
+=item madlex
+X<madlex>
+
+=item madparse
+X<madparse>
+
+=item magic_clear_all_env
+X<magic_clear_all_env>
+
+=item magic_clearenv
+X<magic_clearenv>
+
+=item magic_clearisa
+X<magic_clearisa>
+
+=item magic_clearpack
+X<magic_clearpack>
+
+=item magic_clearsig
+X<magic_clearsig>
+
+=item magic_existspack
+X<magic_existspack>
+
+=item magic_freearylen_p
+X<magic_freearylen_p>
+
+=item magic_freeovrld
+X<magic_freeovrld>
+
+=item magic_get
+X<magic_get>
+
+=item magic_getarylen
+X<magic_getarylen>
+
+=item magic_getdefelem
+X<magic_getdefelem>
+
+=item magic_getnkeys
+X<magic_getnkeys>
+
+=item magic_getpack
+X<magic_getpack>
+
+=item magic_getpos
+X<magic_getpos>
+
+=item magic_getsig
+X<magic_getsig>
+
+=item magic_getsubstr
+X<magic_getsubstr>
+
+=item magic_gettaint
+X<magic_gettaint>
+
+=item magic_getuvar
+X<magic_getuvar>
+
+=item magic_getvec
+X<magic_getvec>
+
+=item magic_killbackrefs
+X<magic_killbackrefs>
+
+=item magic_len
+X<magic_len>
+
+=item magic_methcall
+X<magic_methcall>
+
+=item magic_methpack
+X<magic_methpack>
+
+=item magic_nextpack
+X<magic_nextpack>
+
+=item magic_regdata_cnt
+X<magic_regdata_cnt>
+
+=item magic_regdatum_get
+X<magic_regdatum_get>
+
+=item magic_regdatum_set
+X<magic_regdatum_set>
+
+=item magic_scalarpack
+X<magic_scalarpack>
+
+=item magic_set
+X<magic_set>
+
+=item magic_set_all_env
+X<magic_set_all_env>
+
+=item magic_setamagic
+X<magic_setamagic>
+
+=item magic_setarylen
+X<magic_setarylen>
+
+=item magic_setcollxfrm
+X<magic_setcollxfrm>
+
+=item magic_setdbline
+X<magic_setdbline>
+
+=item magic_setdefelem
+X<magic_setdefelem>
+
+=item magic_setenv
+X<magic_setenv>
+
+=item magic_setisa
+X<magic_setisa>
+
+=item magic_setmglob
+X<magic_setmglob>
+
+=item magic_setnkeys
+X<magic_setnkeys>
+
+=item magic_setpack
+X<magic_setpack>
+
+=item magic_setpos
+X<magic_setpos>
+
+=item magic_setregexp
+X<magic_setregexp>
+
+=item magic_setsig
+X<magic_setsig>
+
+=item magic_setsubstr
+X<magic_setsubstr>
+
+=item magic_settaint
+X<magic_settaint>
+
+=item magic_setutf8
+X<magic_setutf8>
+
+=item magic_setuvar
+X<magic_setuvar>
+
+=item magic_setvec
+X<magic_setvec>
+
+=item magic_sizepack
+X<magic_sizepack>
+
+=item magic_wipepack
+X<magic_wipepack>
+
+=item make_matcher
+X<make_matcher>
+
+=item make_trie
+X<make_trie>
+
+=item make_trie_failtable
+X<make_trie_failtable>
+
+=item malloc_good_size
+X<malloc_good_size>
+
+=item malloced_size
+X<malloced_size>
+
+=item matcher_matches_sv
+X<matcher_matches_sv>
+
+=item measure_struct
+X<measure_struct>
+
+=item mem_collxfrm
+X<mem_collxfrm>
+
+=item mem_log_common
+X<mem_log_common>
+
+=item mess_alloc
+X<mess_alloc>
+
+=item method_common
+X<method_common>
+
+=item missingterm
+X<missingterm>
+
+=item mod
+X<mod>
+
+=item mode_from_discipline
+X<mode_from_discipline>
+
+=item modkids
+X<modkids>
+
+=item more_bodies
+X<more_bodies>
+
+=item more_sv
+X<more_sv>
+
+=item mro_meta_dup
+X<mro_meta_dup>
+
+=item mro_meta_init
+X<mro_meta_init>
+
+=item mul128
+X<mul128>
+
+=item mulexp10
+X<mulexp10>
+
+=item my_attrs
+X<my_attrs>
+
+=item my_betoh16
+X<my_betoh16>
+
+=item my_betoh32
+X<my_betoh32>
+
+=item my_betoh64
+X<my_betoh64>
+
+=item my_betohi
+X<my_betohi>
+
+=item my_betohl
+X<my_betohl>
+
+=item my_betohs
+X<my_betohs>
+
+=item my_clearenv
+X<my_clearenv>
+
+=item my_exit_jump
+X<my_exit_jump>
+
+=item my_htobe16
+X<my_htobe16>
+
+=item my_htobe32
+X<my_htobe32>
+
+=item my_htobe64
+X<my_htobe64>
+
+=item my_htobei
+X<my_htobei>
+
+=item my_htobel
+X<my_htobel>
+
+=item my_htobes
+X<my_htobes>
+
+=item my_htole16
+X<my_htole16>
+
+=item my_htole32
+X<my_htole32>
+
+=item my_htole64
+X<my_htole64>
+
+=item my_htolei
+X<my_htolei>
+
+=item my_htolel
+X<my_htolel>
+
+=item my_htoles
+X<my_htoles>
+
+=item my_kid
+X<my_kid>
+
+=item my_letoh16
+X<my_letoh16>
+
+=item my_letoh32
+X<my_letoh32>
+
+=item my_letoh64
+X<my_letoh64>
+
+=item my_letohi
+X<my_letohi>
+
+=item my_letohl
+X<my_letohl>
+
+=item my_letohs
+X<my_letohs>
+
+=item my_swabn
+X<my_swabn>
+
+=item my_unexec
+X<my_unexec>
+
+=item need_utf8
+X<need_utf8>
+
+=item newDEFSVOP
+X<newDEFSVOP>
+
+=item newGIVWHENOP
+X<newGIVWHENOP>
+
+=item newGP
+X<newGP>
+
+=item newMADPROP
+X<newMADPROP>
+
+=item newMADsv
+X<newMADsv>
+
+=item newTOKEN
+X<newTOKEN>
+
+=item new_constant
+X<new_constant>
+
+=item new_he
+X<new_he>
+
+=item new_logop
+X<new_logop>
+
+=item new_warnings_bitfield
+X<new_warnings_bitfield>
+
+=item next_symbol
+X<next_symbol>
+
+=item nextargv
+X<nextargv>
+
+=item nextchar
+X<nextchar>
+
+=item no_bareword_allowed
+X<no_bareword_allowed>
+
+=item no_fh_allowed
+X<no_fh_allowed>
+
+=item no_op
+X<no_op>
+
+=item not_a_number
+X<not_a_number>
+
+=item nuke_stacks
+X<nuke_stacks>
+
+=item num_overflow
+X<num_overflow>
+
+=item offer_nice_chunk
+X<offer_nice_chunk>
+
+=item oopsAV
+X<oopsAV>
+
+=item oopsHV
+X<oopsHV>
+
+=item op_clear
+X<op_clear>
+
+=item op_const_sv
+X<op_const_sv>
+
+=item op_getmad
+X<op_getmad>
+
+=item op_getmad_weak
+X<op_getmad_weak>
+
+=item op_refcnt_dec
+X<op_refcnt_dec>
+
+=item op_refcnt_inc
+X<op_refcnt_inc>
+
+=item op_xmldump
+X<op_xmldump>
+
+=item open_script
+X<open_script>
+
+=item opt_scalarhv
+X<opt_scalarhv>
+
+=item pack_rec
+X<pack_rec>
+
+=item package
+X<package>
+
+=item package_version
+X<package_version>
+
+=item pad_add_name_sv
+X<pad_add_name_sv>
+
+=item pad_compname_type
+X<pad_compname_type>
+
+=item pad_peg
+X<pad_peg>
+
+=item parse_body
+X<parse_body>
+
+=item parse_unicode_opts
+X<parse_unicode_opts>
+
+=item parser_free
+X<parser_free>
+
+=item path_is_absolute
+X<path_is_absolute>
+
+=item peep
+X<peep>
+
+=item pending_Slabs_to_ro
+X<pending_Slabs_to_ro>
+
+=item pidgone
+X<pidgone>
+
+=item pm_description
+X<pm_description>
+
+=item pmflag
+X<pmflag>
+
+=item pmop_xmldump
+X<pmop_xmldump>
+
+=item pmruntime
+X<pmruntime>
+
+=item pmtrans
+X<pmtrans>
+
+=item prepend_elem
+X<prepend_elem>
+
+=item prepend_madprops
+X<prepend_madprops>
+
+=item printbuf
+X<printbuf>
+
+=item process_special_blocks
+X<process_special_blocks>
+
+=item ptr_table_find
+X<ptr_table_find>
+
+=item put_byte
+X<put_byte>
+
+=item qerror
+X<qerror>
+
+=item qsortsvu
+X<qsortsvu>
+
+=item re_croak2
+X<re_croak2>
+
+=item readpipe_override
+X<readpipe_override>
+
+=item ref_array_or_hash
+X<ref_array_or_hash>
+
+=item refcounted_he_fetch
+X<refcounted_he_fetch>
+
+=item refcounted_he_new_common
+X<refcounted_he_new_common>
+
+=item refcounted_he_value
+X<refcounted_he_value>
+
+=item refkids
+X<refkids>
+
+=item refto
+X<refto>
+
+=item reg
+X<reg>
+
+=item reg_check_named_buff_matched
+X<reg_check_named_buff_matched>
+
+=item reg_named_buff
+X<reg_named_buff>
+
+=item reg_named_buff_iter
+X<reg_named_buff_iter>
+
+=item reg_namedseq
+X<reg_namedseq>
+
+=item reg_node
+X<reg_node>
+
+=item reg_numbered_buff_fetch
+X<reg_numbered_buff_fetch>
+
+=item reg_numbered_buff_length
+X<reg_numbered_buff_length>
+
+=item reg_numbered_buff_store
+X<reg_numbered_buff_store>
+
+=item reg_qr_package
+X<reg_qr_package>
+
+=item reg_recode
+X<reg_recode>
+
+=item reg_scan_name
+X<reg_scan_name>
+
+=item reg_skipcomment
+X<reg_skipcomment>
+
+=item reg_temp_copy
+X<reg_temp_copy>
+
+=item reganode
+X<reganode>
+
+=item regatom
+X<regatom>
+
+=item regbranch
+X<regbranch>
+
+=item regclass
+X<regclass>
+
+=item regcppop
+X<regcppop>
+
+=item regcppush
+X<regcppush>
+
+=item regcurly
+X<regcurly>
+
+=item regdump_extflags
+X<regdump_extflags>
+
+=item reghop3
+X<reghop3>
+
+=item reghop4
+X<reghop4>
+
+=item reghopmaybe3
+X<reghopmaybe3>
+
+=item reginclass
+X<reginclass>
+
+=item reginsert
+X<reginsert>
+
+=item regmatch
+X<regmatch>
+
+=item regpiece
+X<regpiece>
+
+=item regpposixcc
+X<regpposixcc>
+
+=item regprop
+X<regprop>
+
+=item regrepeat
+X<regrepeat>
+
+=item regtail
+X<regtail>
+
+=item regtail_study
+X<regtail_study>
+
+=item regtry
+X<regtry>
+
+=item reguni
+X<reguni>
+
+=item regwhite
+X<regwhite>
+
+=item report_evil_fh
+X<report_evil_fh>
+
+=item require_tie_mod
+X<require_tie_mod>
+
+=item restore_magic
+X<restore_magic>
+
+=item rsignal_restore
+X<rsignal_restore>
+
+=item rsignal_save
+X<rsignal_save>
+
+=item run_body
+X<run_body>
+
+=item run_user_filter
+X<run_user_filter>
+
+=item rxres_free
+X<rxres_free>
+
+=item rxres_restore
+X<rxres_restore>
+
+=item rxres_save
+X<rxres_save>
+
+=item same_dirent
+X<same_dirent>
+
+=item save_freeop
+X<save_freeop>
+
+=item save_hek_flags
+X<save_hek_flags>
+
+=item save_hints
+X<save_hints>
+
+=item save_lines
+X<save_lines>
+
+=item save_magic
+X<save_magic>
+
+=item save_op
+X<save_op>
+
+=item save_pushi32ptr
+X<save_pushi32ptr>
+
+=item save_pushptri32ptr
+X<save_pushptri32ptr>
+
+=item save_pushptrptr
+X<save_pushptrptr>
+
+=item save_scalar_at
+X<save_scalar_at>
+
+=item sawparens
+X<sawparens>
+
+=item scalar
+X<scalar>
+
+=item scalar_mod_type
+X<scalar_mod_type>
+
+=item scalarboolean
+X<scalarboolean>
+
+=item scalarkids
+X<scalarkids>
+
+=item scalarseq
+X<scalarseq>
+
+=item scalarvoid
+X<scalarvoid>
+
+=item scan_commit
+X<scan_commit>
+
+=item scan_const
+X<scan_const>
+
+=item scan_formline
+X<scan_formline>
+
+=item scan_heredoc
+X<scan_heredoc>
+
+=item scan_ident
+X<scan_ident>
+
+=item scan_inputsymbol
+X<scan_inputsymbol>
+
+=item scan_pat
+X<scan_pat>
+
+=item scan_str
+X<scan_str>
+
+=item scan_subst
+X<scan_subst>
+
+=item scan_trans
+X<scan_trans>
+
+=item scan_word
+X<scan_word>
+
+=item scope
+X<scope>
+
+=item search_const
+X<search_const>
+
+=item sequence
+X<sequence>
+
+=item sequence_num
+X<sequence_num>
+
+=item sequence_tail
+X<sequence_tail>
+
+=item share_hek_flags
+X<share_hek_flags>
+
+=item sighandler
+X<sighandler>
+
+=item simplify_sort
+X<simplify_sort>
+
+=item skipspace
+X<skipspace>
+
+=item skipspace0
+X<skipspace0>
+
+=item skipspace1
+X<skipspace1>
+
+=item skipspace2
+X<skipspace2>
+
+=item softref2xv
+X<softref2xv>
+
+=item sortcv
+X<sortcv>
+
+=item sortcv_stacked
+X<sortcv_stacked>
+
+=item sortcv_xsub
+X<sortcv_xsub>
+
+=item space_join_names_mortal
+X<space_join_names_mortal>
+
+=item start_force
+X<start_force>
+
+=item stdize_locale
+X<stdize_locale>
+
+=item store_cop_label
+X<store_cop_label>
+
+=item strip_return
+X<strip_return>
+
+=item study_chunk
+X<study_chunk>
+
+=item sub_crush_depth
+X<sub_crush_depth>
+
+=item sublex_done
+X<sublex_done>
+
+=item sublex_push
+X<sublex_push>
+
+=item sublex_start
+X<sublex_start>
+
+=item sv_2iuv_common
+X<sv_2iuv_common>
+
+=item sv_2iuv_non_preserve
+X<sv_2iuv_non_preserve>
+
+=item sv_add_backref
+X<sv_add_backref>
+
+=item sv_catxmlpvn
+X<sv_catxmlpvn>
+
+=item sv_catxmlsv
+X<sv_catxmlsv>
+
+=item sv_del_backref
+X<sv_del_backref>
+
+=item sv_dup_inc_multiple
+X<sv_dup_inc_multiple>
+
+=item sv_exp_grow
+X<sv_exp_grow>
+
+=item sv_free2
+X<sv_free2>
+
+=item sv_i_ncmp
+X<sv_i_ncmp>
+
+=item sv_kill_backrefs
+X<sv_kill_backrefs>
+
+=item sv_ncmp
+X<sv_ncmp>
+
+=item sv_pos_b2u_midway
+X<sv_pos_b2u_midway>
+
+=item sv_pos_u2b_cached
+X<sv_pos_u2b_cached>
+
+=item sv_pos_u2b_forwards
+X<sv_pos_u2b_forwards>
+
+=item sv_pos_u2b_midway
+X<sv_pos_u2b_midway>
+
+=item sv_release_COW
+X<sv_release_COW>
+
+=item sv_setsv_cow
+X<sv_setsv_cow>
+
+=item sv_unglob
+X<sv_unglob>
+
+=item sv_xmlpeek
+X<sv_xmlpeek>
+
+=item swallow_bom
+X<swallow_bom>
+
+=item swash_get
+X<swash_get>
+
+=item to_byte_substr
+X<to_byte_substr>
+
+=item to_utf8_substr
+X<to_utf8_substr>
+
+=item token_free
+X<token_free>
+
+=item token_getmad
+X<token_getmad>
+
+=item tokenize_use
+X<tokenize_use>
+
+=item tokeq
+X<tokeq>
+
+=item tokereport
+X<tokereport>
+
+=item too_few_arguments
+X<too_few_arguments>
+
+=item too_many_arguments
+X<too_many_arguments>
+
+=item uiv_2buf
+X<uiv_2buf>
+
+=item unpack_rec
+X<unpack_rec>
+
+=item unshare_hek
+X<unshare_hek>
+
+=item unshare_hek_or_pvn
+X<unshare_hek_or_pvn>
+
+=item unwind_handler_stack
+X<unwind_handler_stack>
+
+=item update_debugger_info
+X<update_debugger_info>
+
+=item usage
+X<usage>
+
+=item utf16_textfilter
+X<utf16_textfilter>
+
+=item utf8_mg_pos_cache_update
+X<utf8_mg_pos_cache_update>
+
+=item utilize
+X<utilize>
+
+=item validate_suid
+X<validate_suid>
+
+=item varname
+X<varname>
+
+=item vdie
+X<vdie>
+
+=item vdie_common
+X<vdie_common>
+
+=item vdie_croak_common
+X<vdie_croak_common>
+
+=item visit
+X<visit>
+
+=item vivify_defelem
+X<vivify_defelem>
+
+=item vivify_ref
+X<vivify_ref>
+
+=item wait4pid
+X<wait4pid>
+
+=item watch
+X<watch>
+
+=item write_no_mem
+X<write_no_mem>
+
+=item write_to_stderr
+X<write_to_stderr>
+
+=item xmldump_all
+X<xmldump_all>
+
+=item xmldump_all_perl
+X<xmldump_all_perl>
+
+=item xmldump_attr
+X<xmldump_attr>
+
+=item xmldump_eval
+X<xmldump_eval>
+
+=item xmldump_form
+X<xmldump_form>
+
+=item xmldump_indent
+X<xmldump_indent>
+
+=item xmldump_packsubs
+X<xmldump_packsubs>
+
+=item xmldump_packsubs_perl
+X<xmldump_packsubs_perl>
+
+=item xmldump_sub
+X<xmldump_sub>
+
+=item xmldump_sub_perl
+X<xmldump_sub_perl>
+
+=item xmldump_vindent
+X<xmldump_vindent>
+
+=item yyerror
+X<yyerror>
+
+=item yylex
+X<yylex>
+
+=item yyparse
+X<yyparse>
+
+=item yywarn
+X<yywarn>
+
+=back
+
+
+=head1 AUTHORS
+
+The autodocumentation system was originally added to the Perl core by
+Benjamin Stuhl. Documentation is by whoever was kind enough to
+document their functions.
+
+=head1 SEE ALSO
+
+L<perlguts>, L<perlapi>
+
+=cut
+
+ ex: set ro:
diff --git a/Master/tlpkg/tlperl/lib/pods/perlintro.pod b/Master/tlpkg/tlperl/lib/pods/perlintro.pod
new file mode 100644
index 00000000000..c47274bc646
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlintro.pod
@@ -0,0 +1,678 @@
+=head1 NAME
+
+perlintro -- a brief introduction and overview of Perl
+
+=head1 DESCRIPTION
+
+This document is intended to give you a quick overview of the Perl
+programming language, along with pointers to further documentation. It
+is intended as a "bootstrap" guide for those who are new to the
+language, and provides just enough information for you to be able to
+read other peoples' Perl and understand roughly what it's doing, or
+write your own simple scripts.
+
+This introductory document does not aim to be complete. It does not
+even aim to be entirely accurate. In some cases perfection has been
+sacrificed in the goal of getting the general idea across. You are
+I<strongly> advised to follow this introduction with more information
+from the full Perl manual, the table of contents to which can be found
+in L<perltoc>.
+
+Throughout this document you'll see references to other parts of the
+Perl documentation. You can read that documentation using the C<perldoc>
+command or whatever method you're using to read this document.
+
+=head2 What is Perl?
+
+Perl is a general-purpose programming language originally developed for
+text manipulation and now used for a wide range of tasks including
+system administration, web development, network programming, GUI
+development, and more.
+
+The language is intended to be practical (easy to use, efficient,
+complete) rather than beautiful (tiny, elegant, minimal). Its major
+features are that it's easy to use, supports both procedural and
+object-oriented (OO) programming, has powerful built-in support for text
+processing, and has one of the world's most impressive collections of
+third-party modules.
+
+Different definitions of Perl are given in L<perl>, L<perlfaq1> and
+no doubt other places. From this we can determine that Perl is different
+things to different people, but that lots of people think it's at least
+worth writing about.
+
+=head2 Running Perl programs
+
+To run a Perl program from the Unix command line:
+
+ perl progname.pl
+
+Alternatively, put this as the first line of your script:
+
+ #!/usr/bin/env perl
+
+... and run the script as C</path/to/script.pl>. Of course, it'll need
+to be executable first, so C<chmod 755 script.pl> (under Unix).
+
+(This start line assumes you have the B<env> program. You can also put
+directly the path to your perl executable, like in C<#!/usr/bin/perl>).
+
+For more information, including instructions for other platforms such as
+Windows and Mac OS, read L<perlrun>.
+
+=head2 Safety net
+
+Perl by default is very forgiving. In order to make it more robust
+it is recommended to start every program with the following lines:
+
+ #!/usr/bin/perl
+ use strict;
+ use warnings;
+
+The two additional lines request from perl to catch various common
+problems in your code. They check different things so you need both. A
+potential problem caught by C<use strict;> will cause your code to stop
+immediately when it is encountered, while C<use warnings;> will merely
+give a warning (like the command-line switch B<-w>) and let your code run.
+To read more about them check their respective manual pages at L<strict>
+and L<warnings>.
+
+=head2 Basic syntax overview
+
+A Perl script or program consists of one or more statements. These
+statements are simply written in the script in a straightforward
+fashion. There is no need to have a C<main()> function or anything of
+that kind.
+
+Perl statements end in a semi-colon:
+
+ print "Hello, world";
+
+Comments start with a hash symbol and run to the end of the line
+
+ # This is a comment
+
+Whitespace is irrelevant:
+
+ print
+ "Hello, world"
+ ;
+
+... except inside quoted strings:
+
+ # this would print with a linebreak in the middle
+ print "Hello
+ world";
+
+Double quotes or single quotes may be used around literal strings:
+
+ print "Hello, world";
+ print 'Hello, world';
+
+However, only double quotes "interpolate" variables and special
+characters such as newlines (C<\n>):
+
+ print "Hello, $name\n"; # works fine
+ print 'Hello, $name\n'; # prints $name\n literally
+
+Numbers don't need quotes around them:
+
+ print 42;
+
+You can use parentheses for functions' arguments or omit them
+according to your personal taste. They are only required
+occasionally to clarify issues of precedence.
+
+ print("Hello, world\n");
+ print "Hello, world\n";
+
+More detailed information about Perl syntax can be found in L<perlsyn>.
+
+=head2 Perl variable types
+
+Perl has three main variable types: scalars, arrays, and hashes.
+
+=over 4
+
+=item Scalars
+
+A scalar represents a single value:
+
+ my $animal = "camel";
+ my $answer = 42;
+
+Scalar values can be strings, integers or floating point numbers, and Perl
+will automatically convert between them as required. There is no need
+to pre-declare your variable types, but you have to declare them using
+the C<my> keyword the first time you use them. (This is one of the
+requirements of C<use strict;>.)
+
+Scalar values can be used in various ways:
+
+ print $animal;
+ print "The animal is $animal\n";
+ print "The square of $answer is ", $answer * $answer, "\n";
+
+There are a number of "magic" scalars with names that look like
+punctuation or line noise. These special variables are used for all
+kinds of purposes, and are documented in L<perlvar>. The only one you
+need to know about for now is C<$_> which is the "default variable".
+It's used as the default argument to a number of functions in Perl, and
+it's set implicitly by certain looping constructs.
+
+ print; # prints contents of $_ by default
+
+=item Arrays
+
+An array represents a list of values:
+
+ my @animals = ("camel", "llama", "owl");
+ my @numbers = (23, 42, 69);
+ my @mixed = ("camel", 42, 1.23);
+
+Arrays are zero-indexed. Here's how you get at elements in an array:
+
+ print $animals[0]; # prints "camel"
+ print $animals[1]; # prints "llama"
+
+The special variable C<$#array> tells you the index of the last element
+of an array:
+
+ print $mixed[$#mixed]; # last element, prints 1.23
+
+You might be tempted to use C<$#array + 1> to tell you how many items there
+are in an array. Don't bother. As it happens, using C<@array> where Perl
+expects to find a scalar value ("in scalar context") will give you the number
+of elements in the array:
+
+ if (@animals < 5) { ... }
+
+The elements we're getting from the array start with a C<$> because
+we're getting just a single value out of the array; you ask for a scalar,
+you get a scalar.
+
+To get multiple values from an array:
+
+ @animals[0,1]; # gives ("camel", "llama");
+ @animals[0..2]; # gives ("camel", "llama", "owl");
+ @animals[1..$#animals]; # gives all except the first element
+
+This is called an "array slice".
+
+You can do various useful things to lists:
+
+ my @sorted = sort @animals;
+ my @backwards = reverse @numbers;
+
+There are a couple of special arrays too, such as C<@ARGV> (the command
+line arguments to your script) and C<@_> (the arguments passed to a
+subroutine). These are documented in L<perlvar>.
+
+=item Hashes
+
+A hash represents a set of key/value pairs:
+
+ my %fruit_color = ("apple", "red", "banana", "yellow");
+
+You can use whitespace and the C<< => >> operator to lay them out more
+nicely:
+
+ my %fruit_color = (
+ apple => "red",
+ banana => "yellow",
+ );
+
+To get at hash elements:
+
+ $fruit_color{"apple"}; # gives "red"
+
+You can get at lists of keys and values with C<keys()> and
+C<values()>.
+
+ my @fruits = keys %fruit_colors;
+ my @colors = values %fruit_colors;
+
+Hashes have no particular internal order, though you can sort the keys
+and loop through them.
+
+Just like special scalars and arrays, there are also special hashes.
+The most well known of these is C<%ENV> which contains environment
+variables. Read all about it (and other special variables) in
+L<perlvar>.
+
+=back
+
+Scalars, arrays and hashes are documented more fully in L<perldata>.
+
+More complex data types can be constructed using references, which allow
+you to build lists and hashes within lists and hashes.
+
+A reference is a scalar value and can refer to any other Perl data
+type. So by storing a reference as the value of an array or hash
+element, you can easily create lists and hashes within lists and
+hashes. The following example shows a 2 level hash of hash
+structure using anonymous hash references.
+
+ my $variables = {
+ scalar => {
+ description => "single item",
+ sigil => '$',
+ },
+ array => {
+ description => "ordered list of items",
+ sigil => '@',
+ },
+ hash => {
+ description => "key/value pairs",
+ sigil => '%',
+ },
+ };
+
+ print "Scalars begin with a $variables->{'scalar'}->{'sigil'}\n";
+
+Exhaustive information on the topic of references can be found in
+L<perlreftut>, L<perllol>, L<perlref> and L<perldsc>.
+
+=head2 Variable scoping
+
+Throughout the previous section all the examples have used the syntax:
+
+ my $var = "value";
+
+The C<my> is actually not required; you could just use:
+
+ $var = "value";
+
+However, the above usage will create global variables throughout your
+program, which is bad programming practice. C<my> creates lexically
+scoped variables instead. The variables are scoped to the block
+(i.e. a bunch of statements surrounded by curly-braces) in which they
+are defined.
+
+ my $x = "foo";
+ my $some_condition = 1;
+ if ($some_condition) {
+ my $y = "bar";
+ print $x; # prints "foo"
+ print $y; # prints "bar"
+ }
+ print $x; # prints "foo"
+ print $y; # prints nothing; $y has fallen out of scope
+
+Using C<my> in combination with a C<use strict;> at the top of
+your Perl scripts means that the interpreter will pick up certain common
+programming errors. For instance, in the example above, the final
+C<print $y> would cause a compile-time error and prevent you from
+running the program. Using C<strict> is highly recommended.
+
+=head2 Conditional and looping constructs
+
+Perl has most of the usual conditional and looping constructs. As of Perl
+5.10, it even has a case/switch statement (spelled C<given>/C<when>). See
+L<perlsyn/"Switch statements"> for more details.
+
+The conditions can be any Perl expression. See the list of operators in
+the next section for information on comparison and boolean logic operators,
+which are commonly used in conditional statements.
+
+=over 4
+
+=item if
+
+ if ( condition ) {
+ ...
+ } elsif ( other condition ) {
+ ...
+ } else {
+ ...
+ }
+
+There's also a negated version of it:
+
+ unless ( condition ) {
+ ...
+ }
+
+This is provided as a more readable version of C<if (!I<condition>)>.
+
+Note that the braces are required in Perl, even if you've only got one
+line in the block. However, there is a clever way of making your one-line
+conditional blocks more English like:
+
+ # the traditional way
+ if ($zippy) {
+ print "Yow!";
+ }
+
+ # the Perlish post-condition way
+ print "Yow!" if $zippy;
+ print "We have no bananas" unless $bananas;
+
+=item while
+
+ while ( condition ) {
+ ...
+ }
+
+There's also a negated version, for the same reason we have C<unless>:
+
+ until ( condition ) {
+ ...
+ }
+
+You can also use C<while> in a post-condition:
+
+ print "LA LA LA\n" while 1; # loops forever
+
+=item for
+
+Exactly like C:
+
+ for ($i = 0; $i <= $max; $i++) {
+ ...
+ }
+
+The C style for loop is rarely needed in Perl since Perl provides
+the more friendly list scanning C<foreach> loop.
+
+=item foreach
+
+ foreach (@array) {
+ print "This element is $_\n";
+ }
+
+ print $list[$_] foreach 0 .. $max;
+
+ # you don't have to use the default $_ either...
+ foreach my $key (keys %hash) {
+ print "The value of $key is $hash{$key}\n";
+ }
+
+=back
+
+For more detail on looping constructs (and some that weren't mentioned in
+this overview) see L<perlsyn>.
+
+=head2 Builtin operators and functions
+
+Perl comes with a wide selection of builtin functions. Some of the ones
+we've already seen include C<print>, C<sort> and C<reverse>. A list of
+them is given at the start of L<perlfunc> and you can easily read
+about any given function by using C<perldoc -f I<functionname>>.
+
+Perl operators are documented in full in L<perlop>, but here are a few
+of the most common ones:
+
+=over 4
+
+=item Arithmetic
+
+ + addition
+ - subtraction
+ * multiplication
+ / division
+
+=item Numeric comparison
+
+ == equality
+ != inequality
+ < less than
+ > greater than
+ <= less than or equal
+ >= greater than or equal
+
+=item String comparison
+
+ eq equality
+ ne inequality
+ lt less than
+ gt greater than
+ le less than or equal
+ ge greater than or equal
+
+(Why do we have separate numeric and string comparisons? Because we don't
+have special variable types, and Perl needs to know whether to sort
+numerically (where 99 is less than 100) or alphabetically (where 100 comes
+before 99).
+
+=item Boolean logic
+
+ && and
+ || or
+ ! not
+
+(C<and>, C<or> and C<not> aren't just in the above table as descriptions
+of the operators. They're also supported as operators in their own
+right. They're more readable than the C-style operators, but have
+different precedence to C<&&> and friends. Check L<perlop> for more
+detail.)
+
+=item Miscellaneous
+
+ = assignment
+ . string concatenation
+ x string multiplication
+ .. range operator (creates a list of numbers)
+
+=back
+
+Many operators can be combined with a C<=> as follows:
+
+ $a += 1; # same as $a = $a + 1
+ $a -= 1; # same as $a = $a - 1
+ $a .= "\n"; # same as $a = $a . "\n";
+
+=head2 Files and I/O
+
+You can open a file for input or output using the C<open()> function.
+It's documented in extravagant detail in L<perlfunc> and L<perlopentut>,
+but in short:
+
+ open(my $in, "<", "input.txt") or die "Can't open input.txt: $!";
+ open(my $out, ">", "output.txt") or die "Can't open output.txt: $!";
+ open(my $log, ">>", "my.log") or die "Can't open my.log: $!";
+
+You can read from an open filehandle using the C<< <> >> operator. In
+scalar context it reads a single line from the filehandle, and in list
+context it reads the whole file in, assigning each line to an element of
+the list:
+
+ my $line = <$in>;
+ my @lines = <$in>;
+
+Reading in the whole file at one time is called slurping. It can
+be useful but it may be a memory hog. Most text file processing
+can be done a line at a time with Perl's looping constructs.
+
+The C<< <> >> operator is most often seen in a C<while> loop:
+
+ while (<$in>) { # assigns each line in turn to $_
+ print "Just read in this line: $_";
+ }
+
+We've already seen how to print to standard output using C<print()>.
+However, C<print()> can also take an optional first argument specifying
+which filehandle to print to:
+
+ print STDERR "This is your final warning.\n";
+ print $out $record;
+ print $log $logmessage;
+
+When you're done with your filehandles, you should C<close()> them
+(though to be honest, Perl will clean up after you if you forget):
+
+ close $in or die "$in: $!";
+
+=head2 Regular expressions
+
+Perl's regular expression support is both broad and deep, and is the
+subject of lengthy documentation in L<perlrequick>, L<perlretut>, and
+elsewhere. However, in short:
+
+=over 4
+
+=item Simple matching
+
+ if (/foo/) { ... } # true if $_ contains "foo"
+ if ($a =~ /foo/) { ... } # true if $a contains "foo"
+
+The C<//> matching operator is documented in L<perlop>. It operates on
+C<$_> by default, or can be bound to another variable using the C<=~>
+binding operator (also documented in L<perlop>).
+
+=item Simple substitution
+
+ s/foo/bar/; # replaces foo with bar in $_
+ $a =~ s/foo/bar/; # replaces foo with bar in $a
+ $a =~ s/foo/bar/g; # replaces ALL INSTANCES of foo with bar in $a
+
+The C<s///> substitution operator is documented in L<perlop>.
+
+=item More complex regular expressions
+
+You don't just have to match on fixed strings. In fact, you can match
+on just about anything you could dream of by using more complex regular
+expressions. These are documented at great length in L<perlre>, but for
+the meantime, here's a quick cheat sheet:
+
+ . a single character
+ \s a whitespace character (space, tab, newline, ...)
+ \S non-whitespace character
+ \d a digit (0-9)
+ \D a non-digit
+ \w a word character (a-z, A-Z, 0-9, _)
+ \W a non-word character
+ [aeiou] matches a single character in the given set
+ [^aeiou] matches a single character outside the given set
+ (foo|bar|baz) matches any of the alternatives specified
+
+ ^ start of string
+ $ end of string
+
+Quantifiers can be used to specify how many of the previous thing you
+want to match on, where "thing" means either a literal character, one
+of the metacharacters listed above, or a group of characters or
+metacharacters in parentheses.
+
+ * zero or more of the previous thing
+ + one or more of the previous thing
+ ? zero or one of the previous thing
+ {3} matches exactly 3 of the previous thing
+ {3,6} matches between 3 and 6 of the previous thing
+ {3,} matches 3 or more of the previous thing
+
+Some brief examples:
+
+ /^\d+/ string starts with one or more digits
+ /^$/ nothing in the string (start and end are adjacent)
+ /(\d\s){3}/ a three digits, each followed by a whitespace
+ character (eg "3 4 5 ")
+ /(a.)+/ matches a string in which every odd-numbered letter
+ is a (eg "abacadaf")
+
+ # This loop reads from STDIN, and prints non-blank lines:
+ while (<>) {
+ next if /^$/;
+ print;
+ }
+
+=item Parentheses for capturing
+
+As well as grouping, parentheses serve a second purpose. They can be
+used to capture the results of parts of the regexp match for later use.
+The results end up in C<$1>, C<$2> and so on.
+
+ # a cheap and nasty way to break an email address up into parts
+
+ if ($email =~ /([^@]+)@(.+)/) {
+ print "Username is $1\n";
+ print "Hostname is $2\n";
+ }
+
+=item Other regexp features
+
+Perl regexps also support backreferences, lookaheads, and all kinds of
+other complex details. Read all about them in L<perlrequick>,
+L<perlretut>, and L<perlre>.
+
+=back
+
+=head2 Writing subroutines
+
+Writing subroutines is easy:
+
+ sub logger {
+ my $logmessage = shift;
+ open my $logfile, ">>", "my.log" or die "Could not open my.log: $!";
+ print $logfile $logmessage;
+ }
+
+Now we can use the subroutine just as any other built-in function:
+
+ logger("We have a logger subroutine!");
+
+What's that C<shift>? Well, the arguments to a subroutine are available
+to us as a special array called C<@_> (see L<perlvar> for more on that).
+The default argument to the C<shift> function just happens to be C<@_>.
+So C<my $logmessage = shift;> shifts the first item off the list of
+arguments and assigns it to C<$logmessage>.
+
+We can manipulate C<@_> in other ways too:
+
+ my ($logmessage, $priority) = @_; # common
+ my $logmessage = $_[0]; # uncommon, and ugly
+
+Subroutines can also return values:
+
+ sub square {
+ my $num = shift;
+ my $result = $num * $num;
+ return $result;
+ }
+
+Then use it like:
+
+ $sq = square(8);
+
+For more information on writing subroutines, see L<perlsub>.
+
+=head2 OO Perl
+
+OO Perl is relatively simple and is implemented using references which
+know what sort of object they are based on Perl's concept of packages.
+However, OO Perl is largely beyond the scope of this document.
+Read L<perlboot>, L<perltoot>, L<perltooc> and L<perlobj>.
+
+As a beginning Perl programmer, your most common use of OO Perl will be
+in using third-party modules, which are documented below.
+
+=head2 Using Perl modules
+
+Perl modules provide a range of features to help you avoid reinventing
+the wheel, and can be downloaded from CPAN ( http://www.cpan.org/ ). A
+number of popular modules are included with the Perl distribution
+itself.
+
+Categories of modules range from text manipulation to network protocols
+to database integration to graphics. A categorized list of modules is
+also available from CPAN.
+
+To learn how to install modules you download from CPAN, read
+L<perlmodinstall>.
+
+To learn how to use a particular module, use C<perldoc I<Module::Name>>.
+Typically you will want to C<use I<Module::Name>>, which will then give
+you access to exported functions or an OO interface to the module.
+
+L<perlfaq> contains questions and answers related to many common
+tasks, and often provides suggestions for good CPAN modules to use.
+
+L<perlmod> describes Perl modules in general. L<perlmodlib> lists the
+modules which came with your Perl installation.
+
+If you feel the urge to write Perl modules, L<perlnewmod> will give you
+good advice.
+
+=head1 AUTHOR
+
+Kirrily "Skud" Robert <skud@cpan.org>
diff --git a/Master/tlpkg/tlperl/lib/pods/perliol.pod b/Master/tlpkg/tlperl/lib/pods/perliol.pod
new file mode 100644
index 00000000000..e81484772a7
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perliol.pod
@@ -0,0 +1,1039 @@
+=head1 NAME
+
+perliol - C API for Perl's implementation of IO in Layers.
+
+=head1 SYNOPSIS
+
+ /* Defining a layer ... */
+ #include <perliol.h>
+
+=head1 DESCRIPTION
+
+This document describes the behavior and implementation of the PerlIO
+abstraction described in L<perlapio> when C<USE_PERLIO> is defined (and
+C<USE_SFIO> is not).
+
+=head2 History and Background
+
+The PerlIO abstraction was introduced in perl5.003_02 but languished as
+just an abstraction until perl5.7.0. However during that time a number
+of perl extensions switched to using it, so the API is mostly fixed to
+maintain (source) compatibility.
+
+The aim of the implementation is to provide the PerlIO API in a flexible
+and platform neutral manner. It is also a trial of an "Object Oriented
+C, with vtables" approach which may be applied to Perl 6.
+
+=head2 Basic Structure
+
+PerlIO is a stack of layers.
+
+The low levels of the stack work with the low-level operating system
+calls (file descriptors in C) getting bytes in and out, the higher
+layers of the stack buffer, filter, and otherwise manipulate the I/O,
+and return characters (or bytes) to Perl. Terms I<above> and I<below>
+are used to refer to the relative positioning of the stack layers.
+
+A layer contains a "vtable", the table of I/O operations (at C level
+a table of function pointers), and status flags. The functions in the
+vtable implement operations like "open", "read", and "write".
+
+When I/O, for example "read", is requested, the request goes from Perl
+first down the stack using "read" functions of each layer, then at the
+bottom the input is requested from the operating system services, then
+the result is returned up the stack, finally being interpreted as Perl
+data.
+
+The requests do not necessarily go always all the way down to the
+operating system: that's where PerlIO buffering comes into play.
+
+When you do an open() and specify extra PerlIO layers to be deployed,
+the layers you specify are "pushed" on top of the already existing
+default stack. One way to see it is that "operating system is
+on the left" and "Perl is on the right".
+
+What exact layers are in this default stack depends on a lot of
+things: your operating system, Perl version, Perl compile time
+configuration, and Perl runtime configuration. See L<PerlIO>,
+L<perlrun/PERLIO>, and L<open> for more information.
+
+binmode() operates similarly to open(): by default the specified
+layers are pushed on top of the existing stack.
+
+However, note that even as the specified layers are "pushed on top"
+for open() and binmode(), this doesn't mean that the effects are
+limited to the "top": PerlIO layers can be very 'active' and inspect
+and affect layers also deeper in the stack. As an example there
+is a layer called "raw" which repeatedly "pops" layers until
+it reaches the first layer that has declared itself capable of
+handling binary data. The "pushed" layers are processed in left-to-right
+order.
+
+sysopen() operates (unsurprisingly) at a lower level in the stack than
+open(). For example in Unix or Unix-like systems sysopen() operates
+directly at the level of file descriptors: in the terms of PerlIO
+layers, it uses only the "unix" layer, which is a rather thin wrapper
+on top of the Unix file descriptors.
+
+=head2 Layers vs Disciplines
+
+Initial discussion of the ability to modify IO streams behaviour used
+the term "discipline" for the entities which were added. This came (I
+believe) from the use of the term in "sfio", which in turn borrowed it
+from "line disciplines" on Unix terminals. However, this document (and
+the C code) uses the term "layer".
+
+This is, I hope, a natural term given the implementation, and should
+avoid connotations that are inherent in earlier uses of "discipline"
+for things which are rather different.
+
+=head2 Data Structures
+
+The basic data structure is a PerlIOl:
+
+ typedef struct _PerlIO PerlIOl;
+ typedef struct _PerlIO_funcs PerlIO_funcs;
+ typedef PerlIOl *PerlIO;
+
+ struct _PerlIO
+ {
+ PerlIOl * next; /* Lower layer */
+ PerlIO_funcs * tab; /* Functions for this layer */
+ IV flags; /* Various flags for state */
+ };
+
+A C<PerlIOl *> is a pointer to the struct, and the I<application>
+level C<PerlIO *> is a pointer to a C<PerlIOl *> - i.e. a pointer
+to a pointer to the struct. This allows the application level C<PerlIO *>
+to remain constant while the actual C<PerlIOl *> underneath
+changes. (Compare perl's C<SV *> which remains constant while its
+C<sv_any> field changes as the scalar's type changes.) An IO stream is
+then in general represented as a pointer to this linked-list of
+"layers".
+
+It should be noted that because of the double indirection in a C<PerlIO *>,
+a C<< &(perlio->next) >> "is" a C<PerlIO *>, and so to some degree
+at least one layer can use the "standard" API on the next layer down.
+
+A "layer" is composed of two parts:
+
+=over 4
+
+=item 1.
+
+The functions and attributes of the "layer class".
+
+=item 2.
+
+The per-instance data for a particular handle.
+
+=back
+
+=head2 Functions and Attributes
+
+The functions and attributes are accessed via the "tab" (for table)
+member of C<PerlIOl>. The functions (methods of the layer "class") are
+fixed, and are defined by the C<PerlIO_funcs> type. They are broadly the
+same as the public C<PerlIO_xxxxx> functions:
+
+ struct _PerlIO_funcs
+ {
+ Size_t fsize;
+ char * name;
+ Size_t size;
+ IV kind;
+ IV (*Pushed)(pTHX_ PerlIO *f,const char *mode,SV *arg, PerlIO_funcs *tab);
+ IV (*Popped)(pTHX_ PerlIO *f);
+ PerlIO * (*Open)(pTHX_ PerlIO_funcs *tab,
+ PerlIO_list_t *layers, IV n,
+ const char *mode,
+ int fd, int imode, int perm,
+ PerlIO *old,
+ int narg, SV **args);
+ IV (*Binmode)(pTHX_ PerlIO *f);
+ SV * (*Getarg)(pTHX_ PerlIO *f, CLONE_PARAMS *param, int flags)
+ IV (*Fileno)(pTHX_ PerlIO *f);
+ PerlIO * (*Dup)(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
+ /* Unix-like functions - cf sfio line disciplines */
+ SSize_t (*Read)(pTHX_ PerlIO *f, void *vbuf, Size_t count);
+ SSize_t (*Unread)(pTHX_ PerlIO *f, const void *vbuf, Size_t count);
+ SSize_t (*Write)(pTHX_ PerlIO *f, const void *vbuf, Size_t count);
+ IV (*Seek)(pTHX_ PerlIO *f, Off_t offset, int whence);
+ Off_t (*Tell)(pTHX_ PerlIO *f);
+ IV (*Close)(pTHX_ PerlIO *f);
+ /* Stdio-like buffered IO functions */
+ IV (*Flush)(pTHX_ PerlIO *f);
+ IV (*Fill)(pTHX_ PerlIO *f);
+ IV (*Eof)(pTHX_ PerlIO *f);
+ IV (*Error)(pTHX_ PerlIO *f);
+ void (*Clearerr)(pTHX_ PerlIO *f);
+ void (*Setlinebuf)(pTHX_ PerlIO *f);
+ /* Perl's snooping functions */
+ STDCHAR * (*Get_base)(pTHX_ PerlIO *f);
+ Size_t (*Get_bufsiz)(pTHX_ PerlIO *f);
+ STDCHAR * (*Get_ptr)(pTHX_ PerlIO *f);
+ SSize_t (*Get_cnt)(pTHX_ PerlIO *f);
+ void (*Set_ptrcnt)(pTHX_ PerlIO *f,STDCHAR *ptr,SSize_t cnt);
+ };
+
+The first few members of the struct give a function table size for
+compatibility check "name" for the layer, the size to C<malloc> for the per-instance data,
+and some flags which are attributes of the class as whole (such as whether it is a buffering
+layer), then follow the functions which fall into four basic groups:
+
+=over 4
+
+=item 1.
+
+Opening and setup functions
+
+=item 2.
+
+Basic IO operations
+
+=item 3.
+
+Stdio class buffering options.
+
+=item 4.
+
+Functions to support Perl's traditional "fast" access to the buffer.
+
+=back
+
+A layer does not have to implement all the functions, but the whole
+table has to be present. Unimplemented slots can be NULL (which will
+result in an error when called) or can be filled in with stubs to
+"inherit" behaviour from a "base class". This "inheritance" is fixed
+for all instances of the layer, but as the layer chooses which stubs
+to populate the table, limited "multiple inheritance" is possible.
+
+=head2 Per-instance Data
+
+The per-instance data are held in memory beyond the basic PerlIOl
+struct, by making a PerlIOl the first member of the layer's struct
+thus:
+
+ typedef struct
+ {
+ struct _PerlIO base; /* Base "class" info */
+ STDCHAR * buf; /* Start of buffer */
+ STDCHAR * end; /* End of valid part of buffer */
+ STDCHAR * ptr; /* Current position in buffer */
+ Off_t posn; /* Offset of buf into the file */
+ Size_t bufsiz; /* Real size of buffer */
+ IV oneword; /* Emergency buffer */
+ } PerlIOBuf;
+
+In this way (as for perl's scalars) a pointer to a PerlIOBuf can be
+treated as a pointer to a PerlIOl.
+
+=head2 Layers in action.
+
+ table perlio unix
+ | |
+ +-----------+ +----------+ +--------+
+ PerlIO ->| |--->| next |--->| NULL |
+ +-----------+ +----------+ +--------+
+ | | | buffer | | fd |
+ +-----------+ | | +--------+
+ | | +----------+
+
+
+The above attempts to show how the layer scheme works in a simple case.
+The application's C<PerlIO *> points to an entry in the table(s)
+representing open (allocated) handles. For example the first three slots
+in the table correspond to C<stdin>,C<stdout> and C<stderr>. The table
+in turn points to the current "top" layer for the handle - in this case
+an instance of the generic buffering layer "perlio". That layer in turn
+points to the next layer down - in this case the low-level "unix" layer.
+
+The above is roughly equivalent to a "stdio" buffered stream, but with
+much more flexibility:
+
+=over 4
+
+=item *
+
+If Unix level C<read>/C<write>/C<lseek> is not appropriate for (say)
+sockets then the "unix" layer can be replaced (at open time or even
+dynamically) with a "socket" layer.
+
+=item *
+
+Different handles can have different buffering schemes. The "top"
+layer could be the "mmap" layer if reading disk files was quicker
+using C<mmap> than C<read>. An "unbuffered" stream can be implemented
+simply by not having a buffer layer.
+
+=item *
+
+Extra layers can be inserted to process the data as it flows through.
+This was the driving need for including the scheme in perl 5.7.0+ - we
+needed a mechanism to allow data to be translated between perl's
+internal encoding (conceptually at least Unicode as UTF-8), and the
+"native" format used by the system. This is provided by the
+":encoding(xxxx)" layer which typically sits above the buffering layer.
+
+=item *
+
+A layer can be added that does "\n" to CRLF translation. This layer
+can be used on any platform, not just those that normally do such
+things.
+
+=back
+
+=head2 Per-instance flag bits
+
+The generic flag bits are a hybrid of C<O_XXXXX> style flags deduced
+from the mode string passed to C<PerlIO_open()>, and state bits for
+typical buffer layers.
+
+=over 4
+
+=item PERLIO_F_EOF
+
+End of file.
+
+=item PERLIO_F_CANWRITE
+
+Writes are permitted, i.e. opened as "w" or "r+" or "a", etc.
+
+=item PERLIO_F_CANREAD
+
+Reads are permitted i.e. opened "r" or "w+" (or even "a+" - ick).
+
+=item PERLIO_F_ERROR
+
+An error has occurred (for C<PerlIO_error()>).
+
+=item PERLIO_F_TRUNCATE
+
+Truncate file suggested by open mode.
+
+=item PERLIO_F_APPEND
+
+All writes should be appends.
+
+=item PERLIO_F_CRLF
+
+Layer is performing Win32-like "\n" mapped to CR,LF for output and CR,LF
+mapped to "\n" for input. Normally the provided "crlf" layer is the only
+layer that need bother about this. C<PerlIO_binmode()> will mess with this
+flag rather than add/remove layers if the C<PERLIO_K_CANCRLF> bit is set
+for the layers class.
+
+=item PERLIO_F_UTF8
+
+Data written to this layer should be UTF-8 encoded; data provided
+by this layer should be considered UTF-8 encoded. Can be set on any layer
+by ":utf8" dummy layer. Also set on ":encoding" layer.
+
+=item PERLIO_F_UNBUF
+
+Layer is unbuffered - i.e. write to next layer down should occur for
+each write to this layer.
+
+=item PERLIO_F_WRBUF
+
+The buffer for this layer currently holds data written to it but not sent
+to next layer.
+
+=item PERLIO_F_RDBUF
+
+The buffer for this layer currently holds unconsumed data read from
+layer below.
+
+=item PERLIO_F_LINEBUF
+
+Layer is line buffered. Write data should be passed to next layer down
+whenever a "\n" is seen. Any data beyond the "\n" should then be
+processed.
+
+=item PERLIO_F_TEMP
+
+File has been C<unlink()>ed, or should be deleted on C<close()>.
+
+=item PERLIO_F_OPEN
+
+Handle is open.
+
+=item PERLIO_F_FASTGETS
+
+This instance of this layer supports the "fast C<gets>" interface.
+Normally set based on C<PERLIO_K_FASTGETS> for the class and by the
+existence of the function(s) in the table. However a class that
+normally provides that interface may need to avoid it on a
+particular instance. The "pending" layer needs to do this when
+it is pushed above a layer which does not support the interface.
+(Perl's C<sv_gets()> does not expect the streams fast C<gets> behaviour
+to change during one "get".)
+
+=back
+
+=head2 Methods in Detail
+
+=over 4
+
+=item fsize
+
+ Size_t fsize;
+
+Size of the function table. This is compared against the value PerlIO
+code "knows" as a compatibility check. Future versions I<may> be able
+to tolerate layers compiled against an old version of the headers.
+
+=item name
+
+ char * name;
+
+The name of the layer whose open() method Perl should invoke on
+open(). For example if the layer is called APR, you will call:
+
+ open $fh, ">:APR", ...
+
+and Perl knows that it has to invoke the PerlIOAPR_open() method
+implemented by the APR layer.
+
+=item size
+
+ Size_t size;
+
+The size of the per-instance data structure, e.g.:
+
+ sizeof(PerlIOAPR)
+
+If this field is zero then C<PerlIO_pushed> does not malloc anything
+and assumes layer's Pushed function will do any required layer stack
+manipulation - used to avoid malloc/free overhead for dummy layers.
+If the field is non-zero it must be at least the size of C<PerlIOl>,
+C<PerlIO_pushed> will allocate memory for the layer's data structures
+and link new layer onto the stream's stack. (If the layer's Pushed
+method returns an error indication the layer is popped again.)
+
+=item kind
+
+ IV kind;
+
+=over 4
+
+=item * PERLIO_K_BUFFERED
+
+The layer is buffered.
+
+=item * PERLIO_K_RAW
+
+The layer is acceptable to have in a binmode(FH) stack - i.e. it does not
+(or will configure itself not to) transform bytes passing through it.
+
+=item * PERLIO_K_CANCRLF
+
+Layer can translate between "\n" and CRLF line ends.
+
+=item * PERLIO_K_FASTGETS
+
+Layer allows buffer snooping.
+
+=item * PERLIO_K_MULTIARG
+
+Used when the layer's open() accepts more arguments than usual. The
+extra arguments should come not before the C<MODE> argument. When this
+flag is used it's up to the layer to validate the args.
+
+=back
+
+=item Pushed
+
+ IV (*Pushed)(pTHX_ PerlIO *f,const char *mode, SV *arg);
+
+The only absolutely mandatory method. Called when the layer is pushed
+onto the stack. The C<mode> argument may be NULL if this occurs
+post-open. The C<arg> will be non-C<NULL> if an argument string was
+passed. In most cases this should call C<PerlIOBase_pushed()> to
+convert C<mode> into the appropriate C<PERLIO_F_XXXXX> flags in
+addition to any actions the layer itself takes. If a layer is not
+expecting an argument it need neither save the one passed to it, nor
+provide C<Getarg()> (it could perhaps C<Perl_warn> that the argument
+was un-expected).
+
+Returns 0 on success. On failure returns -1 and should set errno.
+
+=item Popped
+
+ IV (*Popped)(pTHX_ PerlIO *f);
+
+Called when the layer is popped from the stack. A layer will normally
+be popped after C<Close()> is called. But a layer can be popped
+without being closed if the program is dynamically managing layers on
+the stream. In such cases C<Popped()> should free any resources
+(buffers, translation tables, ...) not held directly in the layer's
+struct. It should also C<Unread()> any unconsumed data that has been
+read and buffered from the layer below back to that layer, so that it
+can be re-provided to what ever is now above.
+
+Returns 0 on success and failure. If C<Popped()> returns I<true> then
+I<perlio.c> assumes that either the layer has popped itself, or the
+layer is super special and needs to be retained for other reasons.
+In most cases it should return I<false>.
+
+=item Open
+
+ PerlIO * (*Open)(...);
+
+The C<Open()> method has lots of arguments because it combines the
+functions of perl's C<open>, C<PerlIO_open>, perl's C<sysopen>,
+C<PerlIO_fdopen> and C<PerlIO_reopen>. The full prototype is as
+follows:
+
+ PerlIO * (*Open)(pTHX_ PerlIO_funcs *tab,
+ PerlIO_list_t *layers, IV n,
+ const char *mode,
+ int fd, int imode, int perm,
+ PerlIO *old,
+ int narg, SV **args);
+
+Open should (perhaps indirectly) call C<PerlIO_allocate()> to allocate
+a slot in the table and associate it with the layers information for
+the opened file, by calling C<PerlIO_push>. The I<layers> is an
+array of all the layers destined for the C<PerlIO *>, and any
+arguments passed to them, I<n> is the index into that array of the
+layer being called. The macro C<PerlIOArg> will return a (possibly
+C<NULL>) SV * for the argument passed to the layer.
+
+The I<mode> string is an "C<fopen()>-like" string which would match
+the regular expression C</^[I#]?[rwa]\+?[bt]?$/>.
+
+The C<'I'> prefix is used during creation of C<stdin>..C<stderr> via
+special C<PerlIO_fdopen> calls; the C<'#'> prefix means that this is
+C<sysopen> and that I<imode> and I<perm> should be passed to
+C<PerlLIO_open3>; C<'r'> means B<r>ead, C<'w'> means B<w>rite and
+C<'a'> means B<a>ppend. The C<'+'> suffix means that both reading and
+writing/appending are permitted. The C<'b'> suffix means file should
+be binary, and C<'t'> means it is text. (Almost all layers should do
+the IO in binary mode, and ignore the b/t bits. The C<:crlf> layer
+should be pushed to handle the distinction.)
+
+If I<old> is not C<NULL> then this is a C<PerlIO_reopen>. Perl itself
+does not use this (yet?) and semantics are a little vague.
+
+If I<fd> not negative then it is the numeric file descriptor I<fd>,
+which will be open in a manner compatible with the supplied mode
+string, the call is thus equivalent to C<PerlIO_fdopen>. In this case
+I<nargs> will be zero.
+
+If I<nargs> is greater than zero then it gives the number of arguments
+passed to C<open>, otherwise it will be 1 if for example
+C<PerlIO_open> was called. In simple cases SvPV_nolen(*args) is the
+pathname to open.
+
+Having said all that translation-only layers do not need to provide
+C<Open()> at all, but rather leave the opening to a lower level layer
+and wait to be "pushed". If a layer does provide C<Open()> it should
+normally call the C<Open()> method of next layer down (if any) and
+then push itself on top if that succeeds.
+
+If C<PerlIO_push> was performed and open has failed, it must
+C<PerlIO_pop> itself, since if it's not, the layer won't be removed
+and may cause bad problems.
+
+Returns C<NULL> on failure.
+
+=item Binmode
+
+ IV (*Binmode)(pTHX_ PerlIO *f);
+
+Optional. Used when C<:raw> layer is pushed (explicitly or as a result
+of binmode(FH)). If not present layer will be popped. If present
+should configure layer as binary (or pop itself) and return 0.
+If it returns -1 for error C<binmode> will fail with layer
+still on the stack.
+
+=item Getarg
+
+ SV * (*Getarg)(pTHX_ PerlIO *f,
+ CLONE_PARAMS *param, int flags);
+
+Optional. If present should return an SV * representing the string
+argument passed to the layer when it was
+pushed. e.g. ":encoding(ascii)" would return an SvPV with value
+"ascii". (I<param> and I<flags> arguments can be ignored in most
+cases)
+
+C<Dup> uses C<Getarg> to retrieve the argument originally passed to
+C<Pushed>, so you must implement this function if your layer has an
+extra argument to C<Pushed> and will ever be C<Dup>ed.
+
+=item Fileno
+
+ IV (*Fileno)(pTHX_ PerlIO *f);
+
+Returns the Unix/Posix numeric file descriptor for the handle. Normally
+C<PerlIOBase_fileno()> (which just asks next layer down) will suffice
+for this.
+
+Returns -1 on error, which is considered to include the case where the
+layer cannot provide such a file descriptor.
+
+=item Dup
+
+ PerlIO * (*Dup)(pTHX_ PerlIO *f, PerlIO *o,
+ CLONE_PARAMS *param, int flags);
+
+XXX: Needs more docs.
+
+Used as part of the "clone" process when a thread is spawned (in which
+case param will be non-NULL) and when a stream is being duplicated via
+'&' in the C<open>.
+
+Similar to C<Open>, returns PerlIO* on success, C<NULL> on failure.
+
+=item Read
+
+ SSize_t (*Read)(pTHX_ PerlIO *f, void *vbuf, Size_t count);
+
+Basic read operation.
+
+Typically will call C<Fill> and manipulate pointers (possibly via the
+API). C<PerlIOBuf_read()> may be suitable for derived classes which
+provide "fast gets" methods.
+
+Returns actual bytes read, or -1 on an error.
+
+=item Unread
+
+ SSize_t (*Unread)(pTHX_ PerlIO *f,
+ const void *vbuf, Size_t count);
+
+A superset of stdio's C<ungetc()>. Should arrange for future reads to
+see the bytes in C<vbuf>. If there is no obviously better implementation
+then C<PerlIOBase_unread()> provides the function by pushing a "fake"
+"pending" layer above the calling layer.
+
+Returns the number of unread chars.
+
+=item Write
+
+ SSize_t (*Write)(PerlIO *f, const void *vbuf, Size_t count);
+
+Basic write operation.
+
+Returns bytes written or -1 on an error.
+
+=item Seek
+
+ IV (*Seek)(pTHX_ PerlIO *f, Off_t offset, int whence);
+
+Position the file pointer. Should normally call its own C<Flush>
+method and then the C<Seek> method of next layer down.
+
+Returns 0 on success, -1 on failure.
+
+=item Tell
+
+ Off_t (*Tell)(pTHX_ PerlIO *f);
+
+Return the file pointer. May be based on layers cached concept of
+position to avoid overhead.
+
+Returns -1 on failure to get the file pointer.
+
+=item Close
+
+ IV (*Close)(pTHX_ PerlIO *f);
+
+Close the stream. Should normally call C<PerlIOBase_close()> to flush
+itself and close layers below, and then deallocate any data structures
+(buffers, translation tables, ...) not held directly in the data
+structure.
+
+Returns 0 on success, -1 on failure.
+
+=item Flush
+
+ IV (*Flush)(pTHX_ PerlIO *f);
+
+Should make stream's state consistent with layers below. That is, any
+buffered write data should be written, and file position of lower layers
+adjusted for data read from below but not actually consumed.
+(Should perhaps C<Unread()> such data to the lower layer.)
+
+Returns 0 on success, -1 on failure.
+
+=item Fill
+
+ IV (*Fill)(pTHX_ PerlIO *f);
+
+The buffer for this layer should be filled (for read) from layer
+below. When you "subclass" PerlIOBuf layer, you want to use its
+I<_read> method and to supply your own fill method, which fills the
+PerlIOBuf's buffer.
+
+Returns 0 on success, -1 on failure.
+
+=item Eof
+
+ IV (*Eof)(pTHX_ PerlIO *f);
+
+Return end-of-file indicator. C<PerlIOBase_eof()> is normally sufficient.
+
+Returns 0 on end-of-file, 1 if not end-of-file, -1 on error.
+
+=item Error
+
+ IV (*Error)(pTHX_ PerlIO *f);
+
+Return error indicator. C<PerlIOBase_error()> is normally sufficient.
+
+Returns 1 if there is an error (usually when C<PERLIO_F_ERROR> is set,
+0 otherwise.
+
+=item Clearerr
+
+ void (*Clearerr)(pTHX_ PerlIO *f);
+
+Clear end-of-file and error indicators. Should call C<PerlIOBase_clearerr()>
+to set the C<PERLIO_F_XXXXX> flags, which may suffice.
+
+=item Setlinebuf
+
+ void (*Setlinebuf)(pTHX_ PerlIO *f);
+
+Mark the stream as line buffered. C<PerlIOBase_setlinebuf()> sets the
+PERLIO_F_LINEBUF flag and is normally sufficient.
+
+=item Get_base
+
+ STDCHAR * (*Get_base)(pTHX_ PerlIO *f);
+
+Allocate (if not already done so) the read buffer for this layer and
+return pointer to it. Return NULL on failure.
+
+=item Get_bufsiz
+
+ Size_t (*Get_bufsiz)(pTHX_ PerlIO *f);
+
+Return the number of bytes that last C<Fill()> put in the buffer.
+
+=item Get_ptr
+
+ STDCHAR * (*Get_ptr)(pTHX_ PerlIO *f);
+
+Return the current read pointer relative to this layer's buffer.
+
+=item Get_cnt
+
+ SSize_t (*Get_cnt)(pTHX_ PerlIO *f);
+
+Return the number of bytes left to be read in the current buffer.
+
+=item Set_ptrcnt
+
+ void (*Set_ptrcnt)(pTHX_ PerlIO *f,
+ STDCHAR *ptr, SSize_t cnt);
+
+Adjust the read pointer and count of bytes to match C<ptr> and/or C<cnt>.
+The application (or layer above) must ensure they are consistent.
+(Checking is allowed by the paranoid.)
+
+=back
+
+=head2 Utilities
+
+To ask for the next layer down use PerlIONext(PerlIO *f).
+
+To check that a PerlIO* is valid use PerlIOValid(PerlIO *f). (All
+this does is really just to check that the pointer is non-NULL and
+that the pointer behind that is non-NULL.)
+
+PerlIOBase(PerlIO *f) returns the "Base" pointer, or in other words,
+the C<PerlIOl*> pointer.
+
+PerlIOSelf(PerlIO* f, type) return the PerlIOBase cast to a type.
+
+Perl_PerlIO_or_Base(PerlIO* f, callback, base, failure, args) either
+calls the I<callback> from the functions of the layer I<f> (just by
+the name of the IO function, like "Read") with the I<args>, or if
+there is no such callback, calls the I<base> version of the callback
+with the same args, or if the f is invalid, set errno to EBADF and
+return I<failure>.
+
+Perl_PerlIO_or_fail(PerlIO* f, callback, failure, args) either calls
+the I<callback> of the functions of the layer I<f> with the I<args>,
+or if there is no such callback, set errno to EINVAL. Or if the f is
+invalid, set errno to EBADF and return I<failure>.
+
+Perl_PerlIO_or_Base_void(PerlIO* f, callback, base, args) either calls
+the I<callback> of the functions of the layer I<f> with the I<args>,
+or if there is no such callback, calls the I<base> version of the
+callback with the same args, or if the f is invalid, set errno to
+EBADF.
+
+Perl_PerlIO_or_fail_void(PerlIO* f, callback, args) either calls the
+I<callback> of the functions of the layer I<f> with the I<args>, or if
+there is no such callback, set errno to EINVAL. Or if the f is
+invalid, set errno to EBADF.
+
+=head2 Implementing PerlIO Layers
+
+If you find the implementation document unclear or not sufficient,
+look at the existing PerlIO layer implementations, which include:
+
+=over
+
+=item * C implementations
+
+The F<perlio.c> and F<perliol.h> in the Perl core implement the
+"unix", "perlio", "stdio", "crlf", "utf8", "byte", "raw", "pending"
+layers, and also the "mmap" and "win32" layers if applicable.
+(The "win32" is currently unfinished and unused, to see what is used
+instead in Win32, see L<PerlIO/"Querying the layers of filehandles"> .)
+
+PerlIO::encoding, PerlIO::scalar, PerlIO::via in the Perl core.
+
+PerlIO::gzip and APR::PerlIO (mod_perl 2.0) on CPAN.
+
+=item * Perl implementations
+
+PerlIO::via::QuotedPrint in the Perl core and PerlIO::via::* on CPAN.
+
+=back
+
+If you are creating a PerlIO layer, you may want to be lazy, in other
+words, implement only the methods that interest you. The other methods
+you can either replace with the "blank" methods
+
+ PerlIOBase_noop_ok
+ PerlIOBase_noop_fail
+
+(which do nothing, and return zero and -1, respectively) or for
+certain methods you may assume a default behaviour by using a NULL
+method. The Open method looks for help in the 'parent' layer.
+The following table summarizes the behaviour:
+
+ method behaviour with NULL
+
+ Clearerr PerlIOBase_clearerr
+ Close PerlIOBase_close
+ Dup PerlIOBase_dup
+ Eof PerlIOBase_eof
+ Error PerlIOBase_error
+ Fileno PerlIOBase_fileno
+ Fill FAILURE
+ Flush SUCCESS
+ Getarg SUCCESS
+ Get_base FAILURE
+ Get_bufsiz FAILURE
+ Get_cnt FAILURE
+ Get_ptr FAILURE
+ Open INHERITED
+ Popped SUCCESS
+ Pushed SUCCESS
+ Read PerlIOBase_read
+ Seek FAILURE
+ Set_cnt FAILURE
+ Set_ptrcnt FAILURE
+ Setlinebuf PerlIOBase_setlinebuf
+ Tell FAILURE
+ Unread PerlIOBase_unread
+ Write FAILURE
+
+ FAILURE Set errno (to EINVAL in Unixish, to LIB$_INVARG in VMS) and
+ return -1 (for numeric return values) or NULL (for pointers)
+ INHERITED Inherited from the layer below
+ SUCCESS Return 0 (for numeric return values) or a pointer
+
+=head2 Core Layers
+
+The file C<perlio.c> provides the following layers:
+
+=over 4
+
+=item "unix"
+
+A basic non-buffered layer which calls Unix/POSIX C<read()>, C<write()>,
+C<lseek()>, C<close()>. No buffering. Even on platforms that distinguish
+between O_TEXT and O_BINARY this layer is always O_BINARY.
+
+=item "perlio"
+
+A very complete generic buffering layer which provides the whole of
+PerlIO API. It is also intended to be used as a "base class" for other
+layers. (For example its C<Read()> method is implemented in terms of
+the C<Get_cnt()>/C<Get_ptr()>/C<Set_ptrcnt()> methods).
+
+"perlio" over "unix" provides a complete replacement for stdio as seen
+via PerlIO API. This is the default for USE_PERLIO when system's stdio
+does not permit perl's "fast gets" access, and which do not
+distinguish between C<O_TEXT> and C<O_BINARY>.
+
+=item "stdio"
+
+A layer which provides the PerlIO API via the layer scheme, but
+implements it by calling system's stdio. This is (currently) the default
+if system's stdio provides sufficient access to allow perl's "fast gets"
+access and which do not distinguish between C<O_TEXT> and C<O_BINARY>.
+
+=item "crlf"
+
+A layer derived using "perlio" as a base class. It provides Win32-like
+"\n" to CR,LF translation. Can either be applied above "perlio" or serve
+as the buffer layer itself. "crlf" over "unix" is the default if system
+distinguishes between C<O_TEXT> and C<O_BINARY> opens. (At some point
+"unix" will be replaced by a "native" Win32 IO layer on that platform,
+as Win32's read/write layer has various drawbacks.) The "crlf" layer is
+a reasonable model for a layer which transforms data in some way.
+
+=item "mmap"
+
+If Configure detects C<mmap()> functions this layer is provided (with
+"perlio" as a "base") which does "read" operations by mmap()ing the
+file. Performance improvement is marginal on modern systems, so it is
+mainly there as a proof of concept. It is likely to be unbundled from
+the core at some point. The "mmap" layer is a reasonable model for a
+minimalist "derived" layer.
+
+=item "pending"
+
+An "internal" derivative of "perlio" which can be used to provide
+Unread() function for layers which have no buffer or cannot be
+bothered. (Basically this layer's C<Fill()> pops itself off the stack
+and so resumes reading from layer below.)
+
+=item "raw"
+
+A dummy layer which never exists on the layer stack. Instead when
+"pushed" it actually pops the stack removing itself, it then calls
+Binmode function table entry on all the layers in the stack - normally
+this (via PerlIOBase_binmode) removes any layers which do not have
+C<PERLIO_K_RAW> bit set. Layers can modify that behaviour by defining
+their own Binmode entry.
+
+=item "utf8"
+
+Another dummy layer. When pushed it pops itself and sets the
+C<PERLIO_F_UTF8> flag on the layer which was (and now is once more)
+the top of the stack.
+
+=back
+
+In addition F<perlio.c> also provides a number of C<PerlIOBase_xxxx()>
+functions which are intended to be used in the table slots of classes
+which do not need to do anything special for a particular method.
+
+=head2 Extension Layers
+
+Layers can made available by extension modules. When an unknown layer
+is encountered the PerlIO code will perform the equivalent of :
+
+ use PerlIO 'layer';
+
+Where I<layer> is the unknown layer. F<PerlIO.pm> will then attempt to:
+
+ require PerlIO::layer;
+
+If after that process the layer is still not defined then the C<open>
+will fail.
+
+The following extension layers are bundled with perl:
+
+=over 4
+
+=item ":encoding"
+
+ use Encoding;
+
+makes this layer available, although F<PerlIO.pm> "knows" where to
+find it. It is an example of a layer which takes an argument as it is
+called thus:
+
+ open( $fh, "<:encoding(iso-8859-7)", $pathname );
+
+=item ":scalar"
+
+Provides support for reading data from and writing data to a scalar.
+
+ open( $fh, "+<:scalar", \$scalar );
+
+When a handle is so opened, then reads get bytes from the string value
+of I<$scalar>, and writes change the value. In both cases the position
+in I<$scalar> starts as zero but can be altered via C<seek>, and
+determined via C<tell>.
+
+Please note that this layer is implied when calling open() thus:
+
+ open( $fh, "+<", \$scalar );
+
+=item ":via"
+
+Provided to allow layers to be implemented as Perl code. For instance:
+
+ use PerlIO::via::StripHTML;
+ open( my $fh, "<:via(StripHTML)", "index.html" );
+
+See L<PerlIO::via> for details.
+
+=back
+
+=head1 TODO
+
+Things that need to be done to improve this document.
+
+=over
+
+=item *
+
+Explain how to make a valid fh without going through open()(i.e. apply
+a layer). For example if the file is not opened through perl, but we
+want to get back a fh, like it was opened by Perl.
+
+How PerlIO_apply_layera fits in, where its docs, was it made public?
+
+Currently the example could be something like this:
+
+ PerlIO *foo_to_PerlIO(pTHX_ char *mode, ...)
+ {
+ char *mode; /* "w", "r", etc */
+ const char *layers = ":APR"; /* the layer name */
+ PerlIO *f = PerlIO_allocate(aTHX);
+ if (!f) {
+ return NULL;
+ }
+
+ PerlIO_apply_layers(aTHX_ f, mode, layers);
+
+ if (f) {
+ PerlIOAPR *st = PerlIOSelf(f, PerlIOAPR);
+ /* fill in the st struct, as in _open() */
+ st->file = file;
+ PerlIOBase(f)->flags |= PERLIO_F_OPEN;
+
+ return f;
+ }
+ return NULL;
+ }
+
+=item *
+
+fix/add the documentation in places marked as XXX.
+
+=item *
+
+The handling of errors by the layer is not specified. e.g. when $!
+should be set explicitly, when the error handling should be just
+delegated to the top layer.
+
+Probably give some hints on using SETERRNO() or pointers to where they
+can be found.
+
+=item *
+
+I think it would help to give some concrete examples to make it easier
+to understand the API. Of course I agree that the API has to be
+concise, but since there is no second document that is more of a
+guide, I think that it'd make it easier to start with the doc which is
+an API, but has examples in it in places where things are unclear, to
+a person who is not a PerlIO guru (yet).
+
+=back
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlipc.pod b/Master/tlpkg/tlperl/lib/pods/perlipc.pod
new file mode 100644
index 00000000000..8d9ea9757d0
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlipc.pod
@@ -0,0 +1,1854 @@
+=head1 NAME
+
+perlipc - Perl interprocess communication (signals, fifos, pipes, safe subprocesses, sockets, and semaphores)
+
+=head1 DESCRIPTION
+
+The basic IPC facilities of Perl are built out of the good old Unix
+signals, named pipes, pipe opens, the Berkeley socket routines, and SysV
+IPC calls. Each is used in slightly different situations.
+
+=head1 Signals
+
+Perl uses a simple signal handling model: the %SIG hash contains names
+or references of user-installed signal handlers. These handlers will
+be called with an argument which is the name of the signal that
+triggered it. A signal may be generated intentionally from a
+particular keyboard sequence like control-C or control-Z, sent to you
+from another process, or triggered automatically by the kernel when
+special events transpire, like a child process exiting, your process
+running out of stack space, or hitting file size limit.
+
+For example, to trap an interrupt signal, set up a handler like this:
+
+ sub catch_zap {
+ my $signame = shift;
+ $shucks++;
+ die "Somebody sent me a SIG$signame";
+ }
+ $SIG{INT} = 'catch_zap'; # could fail in modules
+ $SIG{INT} = \&catch_zap; # best strategy
+
+Prior to Perl 5.7.3 it was necessary to do as little as you possibly
+could in your handler; notice how all we do is set a global variable
+and then raise an exception. That's because on most systems,
+libraries are not re-entrant; particularly, memory allocation and I/O
+routines are not. That meant that doing nearly I<anything> in your
+handler could in theory trigger a memory fault and subsequent core
+dump - see L</Deferred Signals (Safe Signals)> below.
+
+The names of the signals are the ones listed out by C<kill -l> on your
+system, or you can retrieve them from the Config module. Set up an
+@signame list indexed by number to get the name and a %signo table
+indexed by name to get the number:
+
+ use Config;
+ defined $Config{sig_name} || die "No sigs?";
+ foreach $name (split(' ', $Config{sig_name})) {
+ $signo{$name} = $i;
+ $signame[$i] = $name;
+ $i++;
+ }
+
+So to check whether signal 17 and SIGALRM were the same, do just this:
+
+ print "signal #17 = $signame[17]\n";
+ if ($signo{ALRM}) {
+ print "SIGALRM is $signo{ALRM}\n";
+ }
+
+You may also choose to assign the strings C<'IGNORE'> or C<'DEFAULT'> as
+the handler, in which case Perl will try to discard the signal or do the
+default thing.
+
+On most Unix platforms, the C<CHLD> (sometimes also known as C<CLD>) signal
+has special behavior with respect to a value of C<'IGNORE'>.
+Setting C<$SIG{CHLD}> to C<'IGNORE'> on such a platform has the effect of
+not creating zombie processes when the parent process fails to C<wait()>
+on its child processes (i.e. child processes are automatically reaped).
+Calling C<wait()> with C<$SIG{CHLD}> set to C<'IGNORE'> usually returns
+C<-1> on such platforms.
+
+Some signals can be neither trapped nor ignored, such as
+the KILL and STOP (but not the TSTP) signals. One strategy for
+temporarily ignoring signals is to use a local() statement, which will be
+automatically restored once your block is exited. (Remember that local()
+values are "inherited" by functions called from within that block.)
+
+ sub precious {
+ local $SIG{INT} = 'IGNORE';
+ &more_functions;
+ }
+ sub more_functions {
+ # interrupts still ignored, for now...
+ }
+
+Sending a signal to a negative process ID means that you send the signal
+to the entire Unix process-group. This code sends a hang-up signal to all
+processes in the current process group (and sets $SIG{HUP} to IGNORE so
+it doesn't kill itself):
+
+ {
+ local $SIG{HUP} = 'IGNORE';
+ kill HUP => -$$;
+ # snazzy writing of: kill('HUP', -$$)
+ }
+
+Another interesting signal to send is signal number zero. This doesn't
+actually affect a child process, but instead checks whether it's alive
+or has changed its UID.
+
+ unless (kill 0 => $kid_pid) {
+ warn "something wicked happened to $kid_pid";
+ }
+
+When directed at a process whose UID is not identical to that
+of the sending process, signal number zero may fail because
+you lack permission to send the signal, even though the process is alive.
+You may be able to determine the cause of failure using C<%!>.
+
+ unless (kill 0 => $pid or $!{EPERM}) {
+ warn "$pid looks dead";
+ }
+
+You might also want to employ anonymous functions for simple signal
+handlers:
+
+ $SIG{INT} = sub { die "\nOutta here!\n" };
+
+But that will be problematic for the more complicated handlers that need
+to reinstall themselves. Because Perl's signal mechanism is currently
+based on the signal(3) function from the C library, you may sometimes be so
+unfortunate as to run on systems where that function is "broken", that
+is, it behaves in the old unreliable SysV way rather than the newer, more
+reasonable BSD and POSIX fashion. So you'll see defensive people writing
+signal handlers like this:
+
+ sub REAPER {
+ $waitedpid = wait;
+ # loathe SysV: it makes us not only reinstate
+ # the handler, but place it after the wait
+ $SIG{CHLD} = \&REAPER;
+ }
+ $SIG{CHLD} = \&REAPER;
+ # now do something that forks...
+
+or better still:
+
+ use POSIX ":sys_wait_h";
+ sub REAPER {
+ my $child;
+ # If a second child dies while in the signal handler caused by the
+ # first death, we won't get another signal. So must loop here else
+ # we will leave the unreaped child as a zombie. And the next time
+ # two children die we get another zombie. And so on.
+ while (($child = waitpid(-1,WNOHANG)) > 0) {
+ $Kid_Status{$child} = $?;
+ }
+ $SIG{CHLD} = \&REAPER; # still loathe SysV
+ }
+ $SIG{CHLD} = \&REAPER;
+ # do something that forks...
+
+Note: qx(), system() and some modules for calling external commands do a
+fork() and wait() for the result. Thus, your signal handler (REAPER in the
+example) will be called. Since wait() was already called by system() or qx()
+the wait() in the signal handler will not see any more zombies and therefore
+block.
+
+The best way to prevent this issue is to use waitpid, as in the following
+example:
+
+ use POSIX ":sys_wait_h"; # for nonblocking read
+
+ my %children;
+
+ $SIG{CHLD} = sub {
+ # don't change $! and $? outside handler
+ local ($!,$?);
+ my $pid = waitpid(-1, WNOHANG);
+ return if $pid == -1;
+ return unless defined $children{$pid};
+ delete $children{$pid};
+ cleanup_child($pid, $?);
+ };
+
+ while (1) {
+ my $pid = fork();
+ if ($pid == 0) {
+ # ...
+ exit 0;
+ } else {
+ $children{$pid}=1;
+ # ...
+ system($command);
+ # ...
+ }
+ }
+
+Signal handling is also used for timeouts in Unix. While safely
+protected within an C<eval{}> block, you set a signal handler to trap
+alarm signals and then schedule to have one delivered to you in some
+number of seconds. Then try your blocking operation, clearing the alarm
+when it's done but not before you've exited your C<eval{}> block. If it
+goes off, you'll use die() to jump out of the block, much as you might
+using longjmp() or throw() in other languages.
+
+Here's an example:
+
+ eval {
+ local $SIG{ALRM} = sub { die "alarm clock restart" };
+ alarm 10;
+ flock(FH, 2); # blocking write lock
+ alarm 0;
+ };
+ if ($@ and $@ !~ /alarm clock restart/) { die }
+
+If the operation being timed out is system() or qx(), this technique
+is liable to generate zombies. If this matters to you, you'll
+need to do your own fork() and exec(), and kill the errant child process.
+
+For more complex signal handling, you might see the standard POSIX
+module. Lamentably, this is almost entirely undocumented, but
+the F<t/lib/posix.t> file from the Perl source distribution has some
+examples in it.
+
+=head2 Handling the SIGHUP Signal in Daemons
+
+A process that usually starts when the system boots and shuts down
+when the system is shut down is called a daemon (Disk And Execution
+MONitor). If a daemon process has a configuration file which is
+modified after the process has been started, there should be a way to
+tell that process to re-read its configuration file, without stopping
+the process. Many daemons provide this mechanism using the C<SIGHUP>
+signal handler. When you want to tell the daemon to re-read the file
+you simply send it the C<SIGHUP> signal.
+
+Not all platforms automatically reinstall their (native) signal
+handlers after a signal delivery. This means that the handler works
+only the first time the signal is sent. The solution to this problem
+is to use C<POSIX> signal handlers if available, their behaviour
+is well-defined.
+
+The following example implements a simple daemon, which restarts
+itself every time the C<SIGHUP> signal is received. The actual code is
+located in the subroutine C<code()>, which simply prints some debug
+info to show that it works and should be replaced with the real code.
+
+ #!/usr/bin/perl -w
+
+ use POSIX ();
+ use FindBin ();
+ use File::Basename ();
+ use File::Spec::Functions;
+
+ $|=1;
+
+ # make the daemon cross-platform, so exec always calls the script
+ # itself with the right path, no matter how the script was invoked.
+ my $script = File::Basename::basename($0);
+ my $SELF = catfile $FindBin::Bin, $script;
+
+ # POSIX unmasks the sigprocmask properly
+ my $sigset = POSIX::SigSet->new();
+ my $action = POSIX::SigAction->new('sigHUP_handler',
+ $sigset,
+ &POSIX::SA_NODEFER);
+ POSIX::sigaction(&POSIX::SIGHUP, $action);
+
+ sub sigHUP_handler {
+ print "got SIGHUP\n";
+ exec($SELF, @ARGV) or die "Couldn't restart: $!\n";
+ }
+
+ code();
+
+ sub code {
+ print "PID: $$\n";
+ print "ARGV: @ARGV\n";
+ my $c = 0;
+ while (++$c) {
+ sleep 2;
+ print "$c\n";
+ }
+ }
+ __END__
+
+
+=head1 Named Pipes
+
+A named pipe (often referred to as a FIFO) is an old Unix IPC
+mechanism for processes communicating on the same machine. It works
+just like a regular, connected anonymous pipes, except that the
+processes rendezvous using a filename and don't have to be related.
+
+To create a named pipe, use the C<POSIX::mkfifo()> function.
+
+ use POSIX qw(mkfifo);
+ mkfifo($path, 0700) or die "mkfifo $path failed: $!";
+
+You can also use the Unix command mknod(1) or on some
+systems, mkfifo(1). These may not be in your normal path.
+
+ # system return val is backwards, so && not ||
+ #
+ $ENV{PATH} .= ":/etc:/usr/etc";
+ if ( system('mknod', $path, 'p')
+ && system('mkfifo', $path) )
+ {
+ die "mk{nod,fifo} $path failed";
+ }
+
+
+A fifo is convenient when you want to connect a process to an unrelated
+one. When you open a fifo, the program will block until there's something
+on the other end.
+
+For example, let's say you'd like to have your F<.signature> file be a
+named pipe that has a Perl program on the other end. Now every time any
+program (like a mailer, news reader, finger program, etc.) tries to read
+from that file, the reading program will block and your program will
+supply the new signature. We'll use the pipe-checking file test B<-p>
+to find out whether anyone (or anything) has accidentally removed our fifo.
+
+ chdir; # go home
+ $FIFO = '.signature';
+
+ while (1) {
+ unless (-p $FIFO) {
+ unlink $FIFO;
+ require POSIX;
+ POSIX::mkfifo($FIFO, 0700)
+ or die "can't mkfifo $FIFO: $!";
+ }
+
+ # next line blocks until there's a reader
+ open (FIFO, "> $FIFO") || die "can't write $FIFO: $!";
+ print FIFO "John Smith (smith\@host.org)\n", `fortune -s`;
+ close FIFO;
+ sleep 2; # to avoid dup signals
+ }
+
+=head2 Deferred Signals (Safe Signals)
+
+In Perls before Perl 5.7.3 by installing Perl code to deal with
+signals, you were exposing yourself to danger from two things. First,
+few system library functions are re-entrant. If the signal interrupts
+while Perl is executing one function (like malloc(3) or printf(3)),
+and your signal handler then calls the same function again, you could
+get unpredictable behavior--often, a core dump. Second, Perl isn't
+itself re-entrant at the lowest levels. If the signal interrupts Perl
+while Perl is changing its own internal data structures, similarly
+unpredictable behaviour may result.
+
+There were two things you could do, knowing this: be paranoid or be
+pragmatic. The paranoid approach was to do as little as possible in your
+signal handler. Set an existing integer variable that already has a
+value, and return. This doesn't help you if you're in a slow system call,
+which will just restart. That means you have to C<die> to longjmp(3) out
+of the handler. Even this is a little cavalier for the true paranoiac,
+who avoids C<die> in a handler because the system I<is> out to get you.
+The pragmatic approach was to say "I know the risks, but prefer the
+convenience", and to do anything you wanted in your signal handler,
+and be prepared to clean up core dumps now and again.
+
+Perl 5.7.3 and later avoid these problems by "deferring" signals.
+That is, when the signal is delivered to the process by
+the system (to the C code that implements Perl) a flag is set, and the
+handler returns immediately. Then at strategic "safe" points in the
+Perl interpreter (e.g. when it is about to execute a new opcode) the
+flags are checked and the Perl level handler from %SIG is
+executed. The "deferred" scheme allows much more flexibility in the
+coding of signal handler as we know Perl interpreter is in a safe
+state, and that we are not in a system library function when the
+handler is called. However the implementation does differ from
+previous Perls in the following ways:
+
+=over 4
+
+=item Long-running opcodes
+
+As the Perl interpreter only looks at the signal flags when it is about
+to execute a new opcode, a signal that arrives during a long-running
+opcode (e.g. a regular expression operation on a very large string) will
+not be seen until the current opcode completes.
+
+N.B. If a signal of any given type fires multiple times during an opcode
+(such as from a fine-grained timer), the handler for that signal will
+only be called once after the opcode completes, and all the other
+instances will be discarded. Furthermore, if your system's signal queue
+gets flooded to the point that there are signals that have been raised
+but not yet caught (and thus not deferred) at the time an opcode
+completes, those signals may well be caught and deferred during
+subsequent opcodes, with sometimes surprising results. For example, you
+may see alarms delivered even after calling C<alarm(0)> as the latter
+stops the raising of alarms but does not cancel the delivery of alarms
+raised but not yet caught. Do not depend on the behaviors described in
+this paragraph as they are side effects of the current implementation and
+may change in future versions of Perl.
+
+
+=item Interrupting IO
+
+When a signal is delivered (e.g. INT control-C) the operating system
+breaks into IO operations like C<read> (used to implement Perls
+E<lt>E<gt> operator). On older Perls the handler was called
+immediately (and as C<read> is not "unsafe" this worked well). With
+the "deferred" scheme the handler is not called immediately, and if
+Perl is using system's C<stdio> library that library may re-start the
+C<read> without returning to Perl and giving it a chance to call the
+%SIG handler. If this happens on your system the solution is to use
+C<:perlio> layer to do IO - at least on those handles which you want
+to be able to break into with signals. (The C<:perlio> layer checks
+the signal flags and calls %SIG handlers before resuming IO operation.)
+
+Note that the default in Perl 5.7.3 and later is to automatically use
+the C<:perlio> layer.
+
+Note that some networking library functions like gethostbyname() are
+known to have their own implementations of timeouts which may conflict
+with your timeouts. If you are having problems with such functions,
+you can try using the POSIX sigaction() function, which bypasses the
+Perl safe signals (note that this means subjecting yourself to
+possible memory corruption, as described above). Instead of setting
+C<$SIG{ALRM}>:
+
+ local $SIG{ALRM} = sub { die "alarm" };
+
+try something like the following:
+
+ use POSIX qw(SIGALRM);
+ POSIX::sigaction(SIGALRM,
+ POSIX::SigAction->new(sub { die "alarm" }))
+ or die "Error setting SIGALRM handler: $!\n";
+
+Another way to disable the safe signal behavior locally is to use
+the C<Perl::Unsafe::Signals> module from CPAN (which will affect
+all signals).
+
+=item Restartable system calls
+
+On systems that supported it, older versions of Perl used the
+SA_RESTART flag when installing %SIG handlers. This meant that
+restartable system calls would continue rather than returning when
+a signal arrived. In order to deliver deferred signals promptly,
+Perl 5.7.3 and later do I<not> use SA_RESTART. Consequently,
+restartable system calls can fail (with $! set to C<EINTR>) in places
+where they previously would have succeeded.
+
+Note that the default C<:perlio> layer will retry C<read>, C<write>
+and C<close> as described above and that interrupted C<wait> and
+C<waitpid> calls will always be retried.
+
+=item Signals as "faults"
+
+Certain signals, e.g. SEGV, ILL, and BUS, are generated as a result of
+virtual memory or other "faults". These are normally fatal and there is
+little a Perl-level handler can do with them, so Perl now delivers them
+immediately rather than attempting to defer them.
+
+=item Signals triggered by operating system state
+
+On some operating systems certain signal handlers are supposed to "do
+something" before returning. One example can be CHLD or CLD which
+indicates a child process has completed. On some operating systems the
+signal handler is expected to C<wait> for the completed child
+process. On such systems the deferred signal scheme will not work for
+those signals (it does not do the C<wait>). Again the failure will
+look like a loop as the operating system will re-issue the signal as
+there are un-waited-for completed child processes.
+
+=back
+
+If you want the old signal behaviour back regardless of possible
+memory corruption, set the environment variable C<PERL_SIGNALS> to
+C<"unsafe"> (a new feature since Perl 5.8.1).
+
+=head1 Using open() for IPC
+
+Perl's basic open() statement can also be used for unidirectional
+interprocess communication by either appending or prepending a pipe
+symbol to the second argument to open(). Here's how to start
+something up in a child process you intend to write to:
+
+ open(SPOOLER, "| cat -v | lpr -h 2>/dev/null")
+ || die "can't fork: $!";
+ local $SIG{PIPE} = sub { die "spooler pipe broke" };
+ print SPOOLER "stuff\n";
+ close SPOOLER || die "bad spool: $! $?";
+
+And here's how to start up a child process you intend to read from:
+
+ open(STATUS, "netstat -an 2>&1 |")
+ || die "can't fork: $!";
+ while (<STATUS>) {
+ next if /^(tcp|udp)/;
+ print;
+ }
+ close STATUS || die "bad netstat: $! $?";
+
+If one can be sure that a particular program is a Perl script that is
+expecting filenames in @ARGV, the clever programmer can write something
+like this:
+
+ % program f1 "cmd1|" - f2 "cmd2|" f3 < tmpfile
+
+and irrespective of which shell it's called from, the Perl program will
+read from the file F<f1>, the process F<cmd1>, standard input (F<tmpfile>
+in this case), the F<f2> file, the F<cmd2> command, and finally the F<f3>
+file. Pretty nifty, eh?
+
+You might notice that you could use backticks for much the
+same effect as opening a pipe for reading:
+
+ print grep { !/^(tcp|udp)/ } `netstat -an 2>&1`;
+ die "bad netstat" if $?;
+
+While this is true on the surface, it's much more efficient to process the
+file one line or record at a time because then you don't have to read the
+whole thing into memory at once. It also gives you finer control of the
+whole process, letting you to kill off the child process early if you'd
+like.
+
+Be careful to check both the open() and the close() return values. If
+you're I<writing> to a pipe, you should also trap SIGPIPE. Otherwise,
+think of what happens when you start up a pipe to a command that doesn't
+exist: the open() will in all likelihood succeed (it only reflects the
+fork()'s success), but then your output will fail--spectacularly. Perl
+can't know whether the command worked because your command is actually
+running in a separate process whose exec() might have failed. Therefore,
+while readers of bogus commands return just a quick end of file, writers
+to bogus command will trigger a signal they'd better be prepared to
+handle. Consider:
+
+ open(FH, "|bogus") or die "can't fork: $!";
+ print FH "bang\n" or die "can't write: $!";
+ close FH or die "can't close: $!";
+
+That won't blow up until the close, and it will blow up with a SIGPIPE.
+To catch it, you could use this:
+
+ $SIG{PIPE} = 'IGNORE';
+ open(FH, "|bogus") or die "can't fork: $!";
+ print FH "bang\n" or die "can't write: $!";
+ close FH or die "can't close: status=$?";
+
+=head2 Filehandles
+
+Both the main process and any child processes it forks share the same
+STDIN, STDOUT, and STDERR filehandles. If both processes try to access
+them at once, strange things can happen. You may also want to close
+or reopen the filehandles for the child. You can get around this by
+opening your pipe with open(), but on some systems this means that the
+child process cannot outlive the parent.
+
+=head2 Background Processes
+
+You can run a command in the background with:
+
+ system("cmd &");
+
+The command's STDOUT and STDERR (and possibly STDIN, depending on your
+shell) will be the same as the parent's. You won't need to catch
+SIGCHLD because of the double-fork taking place (see below for more
+details).
+
+=head2 Complete Dissociation of Child from Parent
+
+In some cases (starting server processes, for instance) you'll want to
+completely dissociate the child process from the parent. This is
+often called daemonization. A well behaved daemon will also chdir()
+to the root directory (so it doesn't prevent unmounting the filesystem
+containing the directory from which it was launched) and redirect its
+standard file descriptors from and to F</dev/null> (so that random
+output doesn't wind up on the user's terminal).
+
+ use POSIX 'setsid';
+
+ sub daemonize {
+ chdir '/' or die "Can't chdir to /: $!";
+ open STDIN, '/dev/null' or die "Can't read /dev/null: $!";
+ open STDOUT, '>/dev/null'
+ or die "Can't write to /dev/null: $!";
+ defined(my $pid = fork) or die "Can't fork: $!";
+ exit if $pid;
+ die "Can't start a new session: $!" if setsid == -1;
+ open STDERR, '>&STDOUT' or die "Can't dup stdout: $!";
+ }
+
+The fork() has to come before the setsid() to ensure that you aren't a
+process group leader (the setsid() will fail if you are). If your
+system doesn't have the setsid() function, open F</dev/tty> and use the
+C<TIOCNOTTY> ioctl() on it instead. See tty(4) for details.
+
+Non-Unix users should check their Your_OS::Process module for other
+solutions.
+
+=head2 Safe Pipe Opens
+
+Another interesting approach to IPC is making your single program go
+multiprocess and communicate between (or even amongst) yourselves. The
+open() function will accept a file argument of either C<"-|"> or C<"|-">
+to do a very interesting thing: it forks a child connected to the
+filehandle you've opened. The child is running the same program as the
+parent. This is useful for safely opening a file when running under an
+assumed UID or GID, for example. If you open a pipe I<to> minus, you can
+write to the filehandle you opened and your kid will find it in his
+STDIN. If you open a pipe I<from> minus, you can read from the filehandle
+you opened whatever your kid writes to his STDOUT.
+
+ use English '-no_match_vars';
+ my $sleep_count = 0;
+
+ do {
+ $pid = open(KID_TO_WRITE, "|-");
+ unless (defined $pid) {
+ warn "cannot fork: $!";
+ die "bailing out" if $sleep_count++ > 6;
+ sleep 10;
+ }
+ } until defined $pid;
+
+ if ($pid) { # parent
+ print KID_TO_WRITE @some_data;
+ close(KID_TO_WRITE) || warn "kid exited $?";
+ } else { # child
+ ($EUID, $EGID) = ($UID, $GID); # suid progs only
+ open (FILE, "> /safe/file")
+ || die "can't open /safe/file: $!";
+ while (<STDIN>) {
+ print FILE; # child's STDIN is parent's KID_TO_WRITE
+ }
+ exit; # don't forget this
+ }
+
+Another common use for this construct is when you need to execute
+something without the shell's interference. With system(), it's
+straightforward, but you can't use a pipe open or backticks safely.
+That's because there's no way to stop the shell from getting its hands on
+your arguments. Instead, use lower-level control to call exec() directly.
+
+Here's a safe backtick or pipe open for read:
+
+ # add error processing as above
+ $pid = open(KID_TO_READ, "-|");
+
+ if ($pid) { # parent
+ while (<KID_TO_READ>) {
+ # do something interesting
+ }
+ close(KID_TO_READ) || warn "kid exited $?";
+
+ } else { # child
+ ($EUID, $EGID) = ($UID, $GID); # suid only
+ exec($program, @options, @args)
+ || die "can't exec program: $!";
+ # NOTREACHED
+ }
+
+
+And here's a safe pipe open for writing:
+
+ # add error processing as above
+ $pid = open(KID_TO_WRITE, "|-");
+ $SIG{PIPE} = sub { die "whoops, $program pipe broke" };
+
+ if ($pid) { # parent
+ for (@data) {
+ print KID_TO_WRITE;
+ }
+ close(KID_TO_WRITE) || warn "kid exited $?";
+
+ } else { # child
+ ($EUID, $EGID) = ($UID, $GID);
+ exec($program, @options, @args)
+ || die "can't exec program: $!";
+ # NOTREACHED
+ }
+
+It is very easy to dead-lock a process using this form of open(), or
+indeed any use of pipe() and multiple sub-processes. The above
+example is 'safe' because it is simple and calls exec(). See
+L</"Avoiding Pipe Deadlocks"> for general safety principles, but there
+are extra gotchas with Safe Pipe Opens.
+
+In particular, if you opened the pipe using C<open FH, "|-">, then you
+cannot simply use close() in the parent process to close an unwanted
+writer. Consider this code:
+
+ $pid = open WRITER, "|-";
+ defined $pid or die "fork failed; $!";
+ if ($pid) {
+ if (my $sub_pid = fork()) {
+ close WRITER;
+ # do something else...
+ }
+ else {
+ # write to WRITER...
+ exit;
+ }
+ }
+ else {
+ # do something with STDIN...
+ exit;
+ }
+
+In the above, the true parent does not want to write to the WRITER
+filehandle, so it closes it. However, because WRITER was opened using
+C<open FH, "|-">, it has a special behaviour: closing it will call
+waitpid() (see L<perlfunc/waitpid>), which waits for the sub-process
+to exit. If the child process ends up waiting for something happening
+in the section marked "do something else", then you have a deadlock.
+
+This can also be a problem with intermediate sub-processes in more
+complicated code, which will call waitpid() on all open filehandles
+during global destruction; in no predictable order.
+
+To solve this, you must manually use pipe(), fork(), and the form of
+open() which sets one file descriptor to another, as below:
+
+ pipe(READER, WRITER);
+ $pid = fork();
+ defined $pid or die "fork failed; $!";
+ if ($pid) {
+ close READER;
+ if (my $sub_pid = fork()) {
+ close WRITER;
+ }
+ else {
+ # write to WRITER...
+ exit;
+ }
+ # write to WRITER...
+ }
+ else {
+ open STDIN, "<&READER";
+ close WRITER;
+ # do something...
+ exit;
+ }
+
+Since Perl 5.8.0, you can also use the list form of C<open> for pipes :
+the syntax
+
+ open KID_PS, "-|", "ps", "aux" or die $!;
+
+forks the ps(1) command (without spawning a shell, as there are more than
+three arguments to open()), and reads its standard output via the
+C<KID_PS> filehandle. The corresponding syntax to write to command
+pipes (with C<"|-"> in place of C<"-|">) is also implemented.
+
+Note that these operations are full Unix forks, which means they may not be
+correctly implemented on alien systems. Additionally, these are not true
+multithreading. If you'd like to learn more about threading, see the
+F<modules> file mentioned below in the SEE ALSO section.
+
+=head2 Avoiding Pipe Deadlocks
+
+In general, if you have more than one sub-process, you need to be very
+careful that any process which does not need the writer half of any
+pipe you create for inter-process communication does not have it open.
+
+The reason for this is that any child process which is reading from
+the pipe and expecting an EOF will never receive it, and therefore
+never exit. A single process closing a pipe is not enough to close it;
+the last process with the pipe open must close it for it to read EOF.
+
+Certain built-in Unix features help prevent this most of
+the time. For instance, filehandles have a 'close on exec' flag (set
+I<en masse> with Perl using the C<$^F> L<perlvar>), so that any
+filehandles which you didn't explicitly route to the STDIN, STDOUT or
+STDERR of a child I<program> will automatically be closed for you.
+
+So, always explicitly and immediately call close() on the writable end
+of any pipe, unless that process is actually writing to it. If you
+don't explicitly call close() then be warned Perl will still close()
+all the filehandles during global destruction. As warned above, if
+those filehandles were opened with Safe Pipe Open, they will also call
+waitpid() and you might again deadlock.
+
+=head2 Bidirectional Communication with Another Process
+
+While this works reasonably well for unidirectional communication, what
+about bidirectional communication? The obvious thing you'd like to do
+doesn't actually work:
+
+ open(PROG_FOR_READING_AND_WRITING, "| some program |")
+
+and if you forget to use the C<use warnings> pragma or the B<-w> flag,
+then you'll miss out entirely on the diagnostic message:
+
+ Can't do bidirectional pipe at -e line 1.
+
+If you really want to, you can use the standard open2() library function
+to catch both ends. There's also an open3() for tridirectional I/O so you
+can also catch your child's STDERR, but doing so would then require an
+awkward select() loop and wouldn't allow you to use normal Perl input
+operations.
+
+If you look at its source, you'll see that open2() uses low-level
+primitives like Unix pipe() and exec() calls to create all the connections.
+While it might have been slightly more efficient by using socketpair(), it
+would have then been even less portable than it already is. The open2()
+and open3() functions are unlikely to work anywhere except on a Unix
+system or some other one purporting to be POSIX compliant.
+
+Here's an example of using open2():
+
+ use FileHandle;
+ use IPC::Open2;
+ $pid = open2(*Reader, *Writer, "cat -u -n" );
+ print Writer "stuff\n";
+ $got = <Reader>;
+
+The problem with this is that Unix buffering is really going to
+ruin your day. Even though your C<Writer> filehandle is auto-flushed,
+and the process on the other end will get your data in a timely manner,
+you can't usually do anything to force it to give it back to you
+in a similarly quick fashion. In this case, we could, because we
+gave I<cat> a B<-u> flag to make it unbuffered. But very few Unix
+commands are designed to operate over pipes, so this seldom works
+unless you yourself wrote the program on the other end of the
+double-ended pipe.
+
+A solution to this is the nonstandard F<Comm.pl> library. It uses
+pseudo-ttys to make your program behave more reasonably:
+
+ require 'Comm.pl';
+ $ph = open_proc('cat -n');
+ for (1..10) {
+ print $ph "a line\n";
+ print "got back ", scalar <$ph>;
+ }
+
+This way you don't have to have control over the source code of the
+program you're using. The F<Comm> library also has expect()
+and interact() functions. Find the library (and we hope its
+successor F<IPC::Chat>) at your nearest CPAN archive as detailed
+in the SEE ALSO section below.
+
+The newer Expect.pm module from CPAN also addresses this kind of thing.
+This module requires two other modules from CPAN: IO::Pty and IO::Stty.
+It sets up a pseudo-terminal to interact with programs that insist on
+using talking to the terminal device driver. If your system is
+amongst those supported, this may be your best bet.
+
+=head2 Bidirectional Communication with Yourself
+
+If you want, you may make low-level pipe() and fork()
+to stitch this together by hand. This example only
+talks to itself, but you could reopen the appropriate
+handles to STDIN and STDOUT and call other processes.
+
+ #!/usr/bin/perl -w
+ # pipe1 - bidirectional communication using two pipe pairs
+ # designed for the socketpair-challenged
+ use IO::Handle; # thousands of lines just for autoflush :-(
+ pipe(PARENT_RDR, CHILD_WTR); # XXX: failure?
+ pipe(CHILD_RDR, PARENT_WTR); # XXX: failure?
+ CHILD_WTR->autoflush(1);
+ PARENT_WTR->autoflush(1);
+
+ if ($pid = fork) {
+ close PARENT_RDR; close PARENT_WTR;
+ print CHILD_WTR "Parent Pid $$ is sending this\n";
+ chomp($line = <CHILD_RDR>);
+ print "Parent Pid $$ just read this: `$line'\n";
+ close CHILD_RDR; close CHILD_WTR;
+ waitpid($pid,0);
+ } else {
+ die "cannot fork: $!" unless defined $pid;
+ close CHILD_RDR; close CHILD_WTR;
+ chomp($line = <PARENT_RDR>);
+ print "Child Pid $$ just read this: `$line'\n";
+ print PARENT_WTR "Child Pid $$ is sending this\n";
+ close PARENT_RDR; close PARENT_WTR;
+ exit;
+ }
+
+But you don't actually have to make two pipe calls. If you
+have the socketpair() system call, it will do this all for you.
+
+ #!/usr/bin/perl -w
+ # pipe2 - bidirectional communication using socketpair
+ # "the best ones always go both ways"
+
+ use Socket;
+ use IO::Handle; # thousands of lines just for autoflush :-(
+ # We say AF_UNIX because although *_LOCAL is the
+ # POSIX 1003.1g form of the constant, many machines
+ # still don't have it.
+ socketpair(CHILD, PARENT, AF_UNIX, SOCK_STREAM, PF_UNSPEC)
+ or die "socketpair: $!";
+
+ CHILD->autoflush(1);
+ PARENT->autoflush(1);
+
+ if ($pid = fork) {
+ close PARENT;
+ print CHILD "Parent Pid $$ is sending this\n";
+ chomp($line = <CHILD>);
+ print "Parent Pid $$ just read this: `$line'\n";
+ close CHILD;
+ waitpid($pid,0);
+ } else {
+ die "cannot fork: $!" unless defined $pid;
+ close CHILD;
+ chomp($line = <PARENT>);
+ print "Child Pid $$ just read this: `$line'\n";
+ print PARENT "Child Pid $$ is sending this\n";
+ close PARENT;
+ exit;
+ }
+
+=head1 Sockets: Client/Server Communication
+
+While not limited to Unix-derived operating systems (e.g., WinSock on PCs
+provides socket support, as do some VMS libraries), you may not have
+sockets on your system, in which case this section probably isn't going to do
+you much good. With sockets, you can do both virtual circuits (i.e., TCP
+streams) and datagrams (i.e., UDP packets). You may be able to do even more
+depending on your system.
+
+The Perl function calls for dealing with sockets have the same names as
+the corresponding system calls in C, but their arguments tend to differ
+for two reasons: first, Perl filehandles work differently than C file
+descriptors. Second, Perl already knows the length of its strings, so you
+don't need to pass that information.
+
+One of the major problems with old socket code in Perl was that it used
+hard-coded values for some of the constants, which severely hurt
+portability. If you ever see code that does anything like explicitly
+setting C<$AF_INET = 2>, you know you're in for big trouble: An
+immeasurably superior approach is to use the C<Socket> module, which more
+reliably grants access to various constants and functions you'll need.
+
+If you're not writing a server/client for an existing protocol like
+NNTP or SMTP, you should give some thought to how your server will
+know when the client has finished talking, and vice-versa. Most
+protocols are based on one-line messages and responses (so one party
+knows the other has finished when a "\n" is received) or multi-line
+messages and responses that end with a period on an empty line
+("\n.\n" terminates a message/response).
+
+=head2 Internet Line Terminators
+
+The Internet line terminator is "\015\012". Under ASCII variants of
+Unix, that could usually be written as "\r\n", but under other systems,
+"\r\n" might at times be "\015\015\012", "\012\012\015", or something
+completely different. The standards specify writing "\015\012" to be
+conformant (be strict in what you provide), but they also recommend
+accepting a lone "\012" on input (but be lenient in what you require).
+We haven't always been very good about that in the code in this manpage,
+but unless you're on a Mac, you'll probably be ok.
+
+=head2 Internet TCP Clients and Servers
+
+Use Internet-domain sockets when you want to do client-server
+communication that might extend to machines outside of your own system.
+
+Here's a sample TCP client using Internet-domain sockets:
+
+ #!/usr/bin/perl -w
+ use strict;
+ use Socket;
+ my ($remote,$port, $iaddr, $paddr, $proto, $line);
+
+ $remote = shift || 'localhost';
+ $port = shift || 2345; # random port
+ if ($port =~ /\D/) { $port = getservbyname($port, 'tcp') }
+ die "No port" unless $port;
+ $iaddr = inet_aton($remote) || die "no host: $remote";
+ $paddr = sockaddr_in($port, $iaddr);
+
+ $proto = getprotobyname('tcp');
+ socket(SOCK, PF_INET, SOCK_STREAM, $proto) || die "socket: $!";
+ connect(SOCK, $paddr) || die "connect: $!";
+ while (defined($line = <SOCK>)) {
+ print $line;
+ }
+
+ close (SOCK) || die "close: $!";
+ exit;
+
+And here's a corresponding server to go along with it. We'll
+leave the address as INADDR_ANY so that the kernel can choose
+the appropriate interface on multihomed hosts. If you want sit
+on a particular interface (like the external side of a gateway
+or firewall machine), you should fill this in with your real address
+instead.
+
+ #!/usr/bin/perl -Tw
+ use strict;
+ BEGIN { $ENV{PATH} = '/usr/ucb:/bin' }
+ use Socket;
+ use Carp;
+ my $EOL = "\015\012";
+
+ sub logmsg { print "$0 $$: @_ at ", scalar localtime, "\n" }
+
+ my $port = shift || 2345;
+ my $proto = getprotobyname('tcp');
+
+ ($port) = $port =~ /^(\d+)$/ or die "invalid port";
+
+ socket(Server, PF_INET, SOCK_STREAM, $proto) || die "socket: $!";
+ setsockopt(Server, SOL_SOCKET, SO_REUSEADDR,
+ pack("l", 1)) || die "setsockopt: $!";
+ bind(Server, sockaddr_in($port, INADDR_ANY)) || die "bind: $!";
+ listen(Server,SOMAXCONN) || die "listen: $!";
+
+ logmsg "server started on port $port";
+
+ my $paddr;
+
+ $SIG{CHLD} = \&REAPER;
+
+ for ( ; $paddr = accept(Client,Server); close Client) {
+ my($port,$iaddr) = sockaddr_in($paddr);
+ my $name = gethostbyaddr($iaddr,AF_INET);
+
+ logmsg "connection from $name [",
+ inet_ntoa($iaddr), "]
+ at port $port";
+
+ print Client "Hello there, $name, it's now ",
+ scalar localtime, $EOL;
+ }
+
+And here's a multithreaded version. It's multithreaded in that
+like most typical servers, it spawns (forks) a slave server to
+handle the client request so that the master server can quickly
+go back to service a new client.
+
+ #!/usr/bin/perl -Tw
+ use strict;
+ BEGIN { $ENV{PATH} = '/usr/ucb:/bin' }
+ use Socket;
+ use Carp;
+ my $EOL = "\015\012";
+
+ sub spawn; # forward declaration
+ sub logmsg { print "$0 $$: @_ at ", scalar localtime, "\n" }
+
+ my $port = shift || 2345;
+ my $proto = getprotobyname('tcp');
+
+ ($port) = $port =~ /^(\d+)$/ or die "invalid port";
+
+ socket(Server, PF_INET, SOCK_STREAM, $proto) || die "socket: $!";
+ setsockopt(Server, SOL_SOCKET, SO_REUSEADDR,
+ pack("l", 1)) || die "setsockopt: $!";
+ bind(Server, sockaddr_in($port, INADDR_ANY)) || die "bind: $!";
+ listen(Server,SOMAXCONN) || die "listen: $!";
+
+ logmsg "server started on port $port";
+
+ my $waitedpid = 0;
+ my $paddr;
+
+ use POSIX ":sys_wait_h";
+ use Errno;
+
+ sub REAPER {
+ local $!; # don't let waitpid() overwrite current error
+ while ((my $pid = waitpid(-1,WNOHANG)) > 0 && WIFEXITED($?)) {
+ logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
+ }
+ $SIG{CHLD} = \&REAPER; # loathe SysV
+ }
+
+ $SIG{CHLD} = \&REAPER;
+
+ while(1) {
+ $paddr = accept(Client, Server) || do {
+ # try again if accept() returned because a signal was received
+ next if $!{EINTR};
+ die "accept: $!";
+ };
+ my ($port, $iaddr) = sockaddr_in($paddr);
+ my $name = gethostbyaddr($iaddr, AF_INET);
+
+ logmsg "connection from $name [",
+ inet_ntoa($iaddr),
+ "] at port $port";
+
+ spawn sub {
+ $|=1;
+ print "Hello there, $name, it's now ", scalar localtime, $EOL;
+ exec '/usr/games/fortune' # XXX: `wrong' line terminators
+ or confess "can't exec fortune: $!";
+ };
+ close Client;
+ }
+
+ sub spawn {
+ my $coderef = shift;
+
+ unless (@_ == 0 && $coderef && ref($coderef) eq 'CODE') {
+ confess "usage: spawn CODEREF";
+ }
+
+ my $pid;
+ if (! defined($pid = fork)) {
+ logmsg "cannot fork: $!";
+ return;
+ }
+ elsif ($pid) {
+ logmsg "begat $pid";
+ return; # I'm the parent
+ }
+ # else I'm the child -- go spawn
+
+ open(STDIN, "<&Client") || die "can't dup client to stdin";
+ open(STDOUT, ">&Client") || die "can't dup client to stdout";
+ ## open(STDERR, ">&STDOUT") || die "can't dup stdout to stderr";
+ exit &$coderef();
+ }
+
+This server takes the trouble to clone off a child version via fork()
+for each incoming request. That way it can handle many requests at
+once, which you might not always want. Even if you don't fork(), the
+listen() will allow that many pending connections. Forking servers
+have to be particularly careful about cleaning up their dead children
+(called "zombies" in Unix parlance), because otherwise you'll quickly
+fill up your process table. The REAPER subroutine is used here to
+call waitpid() for any child processes that have finished, thereby
+ensuring that they terminate cleanly and don't join the ranks of the
+living dead.
+
+Within the while loop we call accept() and check to see if it returns
+a false value. This would normally indicate a system error that needs
+to be reported. However the introduction of safe signals (see
+L</Deferred Signals (Safe Signals)> above) in Perl 5.7.3 means that
+accept() may also be interrupted when the process receives a signal.
+This typically happens when one of the forked sub-processes exits and
+notifies the parent process with a CHLD signal.
+
+If accept() is interrupted by a signal then $! will be set to EINTR.
+If this happens then we can safely continue to the next iteration of
+the loop and another call to accept(). It is important that your
+signal handling code doesn't modify the value of $! or this test will
+most likely fail. In the REAPER subroutine we create a local version
+of $! before calling waitpid(). When waitpid() sets $! to ECHILD (as
+it inevitably does when it has no more children waiting), it will
+update the local copy leaving the original unchanged.
+
+We suggest that you use the B<-T> flag to use taint checking (see L<perlsec>)
+even if we aren't running setuid or setgid. This is always a good idea
+for servers and other programs run on behalf of someone else (like CGI
+scripts), because it lessens the chances that people from the outside will
+be able to compromise your system.
+
+Let's look at another TCP client. This one connects to the TCP "time"
+service on a number of different machines and shows how far their clocks
+differ from the system on which it's being run:
+
+ #!/usr/bin/perl -w
+ use strict;
+ use Socket;
+
+ my $SECS_of_70_YEARS = 2208988800;
+ sub ctime { scalar localtime(shift) }
+
+ my $iaddr = gethostbyname('localhost');
+ my $proto = getprotobyname('tcp');
+ my $port = getservbyname('time', 'tcp');
+ my $paddr = sockaddr_in(0, $iaddr);
+ my($host);
+
+ $| = 1;
+ printf "%-24s %8s %s\n", "localhost", 0, ctime(time());
+
+ foreach $host (@ARGV) {
+ printf "%-24s ", $host;
+ my $hisiaddr = inet_aton($host) || die "unknown host";
+ my $hispaddr = sockaddr_in($port, $hisiaddr);
+ socket(SOCKET, PF_INET, SOCK_STREAM, $proto) || die "socket: $!";
+ connect(SOCKET, $hispaddr) || die "connect: $!";
+ my $rtime = ' ';
+ read(SOCKET, $rtime, 4);
+ close(SOCKET);
+ my $histime = unpack("N", $rtime) - $SECS_of_70_YEARS;
+ printf "%8d %s\n", $histime - time, ctime($histime);
+ }
+
+=head2 Unix-Domain TCP Clients and Servers
+
+That's fine for Internet-domain clients and servers, but what about local
+communications? While you can use the same setup, sometimes you don't
+want to. Unix-domain sockets are local to the current host, and are often
+used internally to implement pipes. Unlike Internet domain sockets, Unix
+domain sockets can show up in the file system with an ls(1) listing.
+
+ % ls -l /dev/log
+ srw-rw-rw- 1 root 0 Oct 31 07:23 /dev/log
+
+You can test for these with Perl's B<-S> file test:
+
+ unless ( -S '/dev/log' ) {
+ die "something's wicked with the log system";
+ }
+
+Here's a sample Unix-domain client:
+
+ #!/usr/bin/perl -w
+ use Socket;
+ use strict;
+ my ($rendezvous, $line);
+
+ $rendezvous = shift || 'catsock';
+ socket(SOCK, PF_UNIX, SOCK_STREAM, 0) || die "socket: $!";
+ connect(SOCK, sockaddr_un($rendezvous)) || die "connect: $!";
+ while (defined($line = <SOCK>)) {
+ print $line;
+ }
+ exit;
+
+And here's a corresponding server. You don't have to worry about silly
+network terminators here because Unix domain sockets are guaranteed
+to be on the localhost, and thus everything works right.
+
+ #!/usr/bin/perl -Tw
+ use strict;
+ use Socket;
+ use Carp;
+
+ BEGIN { $ENV{PATH} = '/usr/ucb:/bin' }
+ sub spawn; # forward declaration
+ sub logmsg { print "$0 $$: @_ at ", scalar localtime, "\n" }
+
+ my $NAME = 'catsock';
+ my $uaddr = sockaddr_un($NAME);
+ my $proto = getprotobyname('tcp');
+
+ socket(Server,PF_UNIX,SOCK_STREAM,0) || die "socket: $!";
+ unlink($NAME);
+ bind (Server, $uaddr) || die "bind: $!";
+ listen(Server,SOMAXCONN) || die "listen: $!";
+
+ logmsg "server started on $NAME";
+
+ my $waitedpid;
+
+ use POSIX ":sys_wait_h";
+ sub REAPER {
+ my $child;
+ while (($waitedpid = waitpid(-1,WNOHANG)) > 0) {
+ logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
+ }
+ $SIG{CHLD} = \&REAPER; # loathe SysV
+ }
+
+ $SIG{CHLD} = \&REAPER;
+
+
+ for ( $waitedpid = 0;
+ accept(Client,Server) || $waitedpid;
+ $waitedpid = 0, close Client)
+ {
+ next if $waitedpid;
+ logmsg "connection on $NAME";
+ spawn sub {
+ print "Hello there, it's now ", scalar localtime, "\n";
+ exec '/usr/games/fortune' or die "can't exec fortune: $!";
+ };
+ }
+
+ sub spawn {
+ my $coderef = shift;
+
+ unless (@_ == 0 && $coderef && ref($coderef) eq 'CODE') {
+ confess "usage: spawn CODEREF";
+ }
+
+ my $pid;
+ if (!defined($pid = fork)) {
+ logmsg "cannot fork: $!";
+ return;
+ } elsif ($pid) {
+ logmsg "begat $pid";
+ return; # I'm the parent
+ }
+ # else I'm the child -- go spawn
+
+ open(STDIN, "<&Client") || die "can't dup client to stdin";
+ open(STDOUT, ">&Client") || die "can't dup client to stdout";
+ ## open(STDERR, ">&STDOUT") || die "can't dup stdout to stderr";
+ exit &$coderef();
+ }
+
+As you see, it's remarkably similar to the Internet domain TCP server, so
+much so, in fact, that we've omitted several duplicate functions--spawn(),
+logmsg(), ctime(), and REAPER()--which are exactly the same as in the
+other server.
+
+So why would you ever want to use a Unix domain socket instead of a
+simpler named pipe? Because a named pipe doesn't give you sessions. You
+can't tell one process's data from another's. With socket programming,
+you get a separate session for each client: that's why accept() takes two
+arguments.
+
+For example, let's say that you have a long running database server daemon
+that you want folks from the World Wide Web to be able to access, but only
+if they go through a CGI interface. You'd have a small, simple CGI
+program that does whatever checks and logging you feel like, and then acts
+as a Unix-domain client and connects to your private server.
+
+=head1 TCP Clients with IO::Socket
+
+For those preferring a higher-level interface to socket programming, the
+IO::Socket module provides an object-oriented approach. IO::Socket is
+included as part of the standard Perl distribution as of the 5.004
+release. If you're running an earlier version of Perl, just fetch
+IO::Socket from CPAN, where you'll also find modules providing easy
+interfaces to the following systems: DNS, FTP, Ident (RFC 931), NIS and
+NISPlus, NNTP, Ping, POP3, SMTP, SNMP, SSLeay, Telnet, and Time--just
+to name a few.
+
+=head2 A Simple Client
+
+Here's a client that creates a TCP connection to the "daytime"
+service at port 13 of the host name "localhost" and prints out everything
+that the server there cares to provide.
+
+ #!/usr/bin/perl -w
+ use IO::Socket;
+ $remote = IO::Socket::INET->new(
+ Proto => "tcp",
+ PeerAddr => "localhost",
+ PeerPort => "daytime(13)",
+ )
+ or die "cannot connect to daytime port at localhost";
+ while ( <$remote> ) { print }
+
+When you run this program, you should get something back that
+looks like this:
+
+ Wed May 14 08:40:46 MDT 1997
+
+Here are what those parameters to the C<new> constructor mean:
+
+=over 4
+
+=item C<Proto>
+
+This is which protocol to use. In this case, the socket handle returned
+will be connected to a TCP socket, because we want a stream-oriented
+connection, that is, one that acts pretty much like a plain old file.
+Not all sockets are this of this type. For example, the UDP protocol
+can be used to make a datagram socket, used for message-passing.
+
+=item C<PeerAddr>
+
+This is the name or Internet address of the remote host the server is
+running on. We could have specified a longer name like C<"www.perl.com">,
+or an address like C<"204.148.40.9">. For demonstration purposes, we've
+used the special hostname C<"localhost">, which should always mean the
+current machine you're running on. The corresponding Internet address
+for localhost is C<"127.1">, if you'd rather use that.
+
+=item C<PeerPort>
+
+This is the service name or port number we'd like to connect to.
+We could have gotten away with using just C<"daytime"> on systems with a
+well-configured system services file,[FOOTNOTE: The system services file
+is in I</etc/services> under Unix] but just in case, we've specified the
+port number (13) in parentheses. Using just the number would also have
+worked, but constant numbers make careful programmers nervous.
+
+=back
+
+Notice how the return value from the C<new> constructor is used as
+a filehandle in the C<while> loop? That's what's called an indirect
+filehandle, a scalar variable containing a filehandle. You can use
+it the same way you would a normal filehandle. For example, you
+can read one line from it this way:
+
+ $line = <$handle>;
+
+all remaining lines from is this way:
+
+ @lines = <$handle>;
+
+and send a line of data to it this way:
+
+ print $handle "some data\n";
+
+=head2 A Webget Client
+
+Here's a simple client that takes a remote host to fetch a document
+from, and then a list of documents to get from that host. This is a
+more interesting client than the previous one because it first sends
+something to the server before fetching the server's response.
+
+ #!/usr/bin/perl -w
+ use IO::Socket;
+ unless (@ARGV > 1) { die "usage: $0 host document ..." }
+ $host = shift(@ARGV);
+ $EOL = "\015\012";
+ $BLANK = $EOL x 2;
+ foreach $document ( @ARGV ) {
+ $remote = IO::Socket::INET->new( Proto => "tcp",
+ PeerAddr => $host,
+ PeerPort => "http(80)",
+ );
+ unless ($remote) { die "cannot connect to http daemon on $host" }
+ $remote->autoflush(1);
+ print $remote "GET $document HTTP/1.0" . $BLANK;
+ while ( <$remote> ) { print }
+ close $remote;
+ }
+
+The web server handing the "http" service, which is assumed to be at
+its standard port, number 80. If the web server you're trying to
+connect to is at a different port (like 1080 or 8080), you should specify
+as the named-parameter pair, C<< PeerPort => 8080 >>. The C<autoflush>
+method is used on the socket because otherwise the system would buffer
+up the output we sent it. (If you're on a Mac, you'll also need to
+change every C<"\n"> in your code that sends data over the network to
+be a C<"\015\012"> instead.)
+
+Connecting to the server is only the first part of the process: once you
+have the connection, you have to use the server's language. Each server
+on the network has its own little command language that it expects as
+input. The string that we send to the server starting with "GET" is in
+HTTP syntax. In this case, we simply request each specified document.
+Yes, we really are making a new connection for each document, even though
+it's the same host. That's the way you always used to have to speak HTTP.
+Recent versions of web browsers may request that the remote server leave
+the connection open a little while, but the server doesn't have to honor
+such a request.
+
+Here's an example of running that program, which we'll call I<webget>:
+
+ % webget www.perl.com /guanaco.html
+ HTTP/1.1 404 File Not Found
+ Date: Thu, 08 May 1997 18:02:32 GMT
+ Server: Apache/1.2b6
+ Connection: close
+ Content-type: text/html
+
+ <HEAD><TITLE>404 File Not Found</TITLE></HEAD>
+ <BODY><H1>File Not Found</H1>
+ The requested URL /guanaco.html was not found on this server.<P>
+ </BODY>
+
+Ok, so that's not very interesting, because it didn't find that
+particular document. But a long response wouldn't have fit on this page.
+
+For a more fully-featured version of this program, you should look to
+the I<lwp-request> program included with the LWP modules from CPAN.
+
+=head2 Interactive Client with IO::Socket
+
+Well, that's all fine if you want to send one command and get one answer,
+but what about setting up something fully interactive, somewhat like
+the way I<telnet> works? That way you can type a line, get the answer,
+type a line, get the answer, etc.
+
+This client is more complicated than the two we've done so far, but if
+you're on a system that supports the powerful C<fork> call, the solution
+isn't that rough. Once you've made the connection to whatever service
+you'd like to chat with, call C<fork> to clone your process. Each of
+these two identical process has a very simple job to do: the parent
+copies everything from the socket to standard output, while the child
+simultaneously copies everything from standard input to the socket.
+To accomplish the same thing using just one process would be I<much>
+harder, because it's easier to code two processes to do one thing than it
+is to code one process to do two things. (This keep-it-simple principle
+a cornerstones of the Unix philosophy, and good software engineering as
+well, which is probably why it's spread to other systems.)
+
+Here's the code:
+
+ #!/usr/bin/perl -w
+ use strict;
+ use IO::Socket;
+ my ($host, $port, $kidpid, $handle, $line);
+
+ unless (@ARGV == 2) { die "usage: $0 host port" }
+ ($host, $port) = @ARGV;
+
+ # create a tcp connection to the specified host and port
+ $handle = IO::Socket::INET->new(Proto => "tcp",
+ PeerAddr => $host,
+ PeerPort => $port)
+ or die "can't connect to port $port on $host: $!";
+
+ $handle->autoflush(1); # so output gets there right away
+ print STDERR "[Connected to $host:$port]\n";
+
+ # split the program into two processes, identical twins
+ die "can't fork: $!" unless defined($kidpid = fork());
+
+ # the if{} block runs only in the parent process
+ if ($kidpid) {
+ # copy the socket to standard output
+ while (defined ($line = <$handle>)) {
+ print STDOUT $line;
+ }
+ kill("TERM", $kidpid); # send SIGTERM to child
+ }
+ # the else{} block runs only in the child process
+ else {
+ # copy standard input to the socket
+ while (defined ($line = <STDIN>)) {
+ print $handle $line;
+ }
+ }
+
+The C<kill> function in the parent's C<if> block is there to send a
+signal to our child process (current running in the C<else> block)
+as soon as the remote server has closed its end of the connection.
+
+If the remote server sends data a byte at time, and you need that
+data immediately without waiting for a newline (which might not happen),
+you may wish to replace the C<while> loop in the parent with the
+following:
+
+ my $byte;
+ while (sysread($handle, $byte, 1) == 1) {
+ print STDOUT $byte;
+ }
+
+Making a system call for each byte you want to read is not very efficient
+(to put it mildly) but is the simplest to explain and works reasonably
+well.
+
+=head1 TCP Servers with IO::Socket
+
+As always, setting up a server is little bit more involved than running a client.
+The model is that the server creates a special kind of socket that
+does nothing but listen on a particular port for incoming connections.
+It does this by calling the C<< IO::Socket::INET->new() >> method with
+slightly different arguments than the client did.
+
+=over 4
+
+=item Proto
+
+This is which protocol to use. Like our clients, we'll
+still specify C<"tcp"> here.
+
+=item LocalPort
+
+We specify a local
+port in the C<LocalPort> argument, which we didn't do for the client.
+This is service name or port number for which you want to be the
+server. (Under Unix, ports under 1024 are restricted to the
+superuser.) In our sample, we'll use port 9000, but you can use
+any port that's not currently in use on your system. If you try
+to use one already in used, you'll get an "Address already in use"
+message. Under Unix, the C<netstat -a> command will show
+which services current have servers.
+
+=item Listen
+
+The C<Listen> parameter is set to the maximum number of
+pending connections we can accept until we turn away incoming clients.
+Think of it as a call-waiting queue for your telephone.
+The low-level Socket module has a special symbol for the system maximum, which
+is SOMAXCONN.
+
+=item Reuse
+
+The C<Reuse> parameter is needed so that we restart our server
+manually without waiting a few minutes to allow system buffers to
+clear out.
+
+=back
+
+Once the generic server socket has been created using the parameters
+listed above, the server then waits for a new client to connect
+to it. The server blocks in the C<accept> method, which eventually accepts a
+bidirectional connection from the remote client. (Make sure to autoflush
+this handle to circumvent buffering.)
+
+To add to user-friendliness, our server prompts the user for commands.
+Most servers don't do this. Because of the prompt without a newline,
+you'll have to use the C<sysread> variant of the interactive client above.
+
+This server accepts one of five different commands, sending output
+back to the client. Note that unlike most network servers, this one
+only handles one incoming client at a time. Multithreaded servers are
+covered in Chapter 6 of the Camel.
+
+Here's the code. We'll
+
+ #!/usr/bin/perl -w
+ use IO::Socket;
+ use Net::hostent; # for OO version of gethostbyaddr
+
+ $PORT = 9000; # pick something not in use
+
+ $server = IO::Socket::INET->new( Proto => 'tcp',
+ LocalPort => $PORT,
+ Listen => SOMAXCONN,
+ Reuse => 1);
+
+ die "can't setup server" unless $server;
+ print "[Server $0 accepting clients]\n";
+
+ while ($client = $server->accept()) {
+ $client->autoflush(1);
+ print $client "Welcome to $0; type help for command list.\n";
+ $hostinfo = gethostbyaddr($client->peeraddr);
+ printf "[Connect from %s]\n", $hostinfo ? $hostinfo->name : $client->peerhost;
+ print $client "Command? ";
+ while ( <$client>) {
+ next unless /\S/; # blank line
+ if (/quit|exit/i) { last; }
+ elsif (/date|time/i) { printf $client "%s\n", scalar localtime; }
+ elsif (/who/i ) { print $client `who 2>&1`; }
+ elsif (/cookie/i ) { print $client `/usr/games/fortune 2>&1`; }
+ elsif (/motd/i ) { print $client `cat /etc/motd 2>&1`; }
+ else {
+ print $client "Commands: quit date who cookie motd\n";
+ }
+ } continue {
+ print $client "Command? ";
+ }
+ close $client;
+ }
+
+=head1 UDP: Message Passing
+
+Another kind of client-server setup is one that uses not connections, but
+messages. UDP communications involve much lower overhead but also provide
+less reliability, as there are no promises that messages will arrive at
+all, let alone in order and unmangled. Still, UDP offers some advantages
+over TCP, including being able to "broadcast" or "multicast" to a whole
+bunch of destination hosts at once (usually on your local subnet). If you
+find yourself overly concerned about reliability and start building checks
+into your message system, then you probably should use just TCP to start
+with.
+
+Note that UDP datagrams are I<not> a bytestream and should not be treated
+as such. This makes using I/O mechanisms with internal buffering
+like stdio (i.e. print() and friends) especially cumbersome. Use syswrite(),
+or better send(), like in the example below.
+
+Here's a UDP program similar to the sample Internet TCP client given
+earlier. However, instead of checking one host at a time, the UDP version
+will check many of them asynchronously by simulating a multicast and then
+using select() to do a timed-out wait for I/O. To do something similar
+with TCP, you'd have to use a different socket handle for each host.
+
+ #!/usr/bin/perl -w
+ use strict;
+ use Socket;
+ use Sys::Hostname;
+
+ my ( $count, $hisiaddr, $hispaddr, $histime,
+ $host, $iaddr, $paddr, $port, $proto,
+ $rin, $rout, $rtime, $SECS_of_70_YEARS);
+
+ $SECS_of_70_YEARS = 2208988800;
+
+ $iaddr = gethostbyname(hostname());
+ $proto = getprotobyname('udp');
+ $port = getservbyname('time', 'udp');
+ $paddr = sockaddr_in(0, $iaddr); # 0 means let kernel pick
+
+ socket(SOCKET, PF_INET, SOCK_DGRAM, $proto) || die "socket: $!";
+ bind(SOCKET, $paddr) || die "bind: $!";
+
+ $| = 1;
+ printf "%-12s %8s %s\n", "localhost", 0, scalar localtime time;
+ $count = 0;
+ for $host (@ARGV) {
+ $count++;
+ $hisiaddr = inet_aton($host) || die "unknown host";
+ $hispaddr = sockaddr_in($port, $hisiaddr);
+ defined(send(SOCKET, 0, 0, $hispaddr)) || die "send $host: $!";
+ }
+
+ $rin = '';
+ vec($rin, fileno(SOCKET), 1) = 1;
+
+ # timeout after 10.0 seconds
+ while ($count && select($rout = $rin, undef, undef, 10.0)) {
+ $rtime = '';
+ ($hispaddr = recv(SOCKET, $rtime, 4, 0)) || die "recv: $!";
+ ($port, $hisiaddr) = sockaddr_in($hispaddr);
+ $host = gethostbyaddr($hisiaddr, AF_INET);
+ $histime = unpack("N", $rtime) - $SECS_of_70_YEARS;
+ printf "%-12s ", $host;
+ printf "%8d %s\n", $histime - time, scalar localtime($histime);
+ $count--;
+ }
+
+Note that this example does not include any retries and may consequently
+fail to contact a reachable host. The most prominent reason for this
+is congestion of the queues on the sending host if the number of
+list of hosts to contact is sufficiently large.
+
+=head1 SysV IPC
+
+While System V IPC isn't so widely used as sockets, it still has some
+interesting uses. You can't, however, effectively use SysV IPC or
+Berkeley mmap() to have shared memory so as to share a variable amongst
+several processes. That's because Perl would reallocate your string when
+you weren't wanting it to.
+
+Here's a small example showing shared memory usage.
+
+ use IPC::SysV qw(IPC_PRIVATE IPC_RMID S_IRUSR S_IWUSR);
+
+ $size = 2000;
+ $id = shmget(IPC_PRIVATE, $size, S_IRUSR|S_IWUSR) // die "$!";
+ print "shm key $id\n";
+
+ $message = "Message #1";
+ shmwrite($id, $message, 0, 60) || die "$!";
+ print "wrote: '$message'\n";
+ shmread($id, $buff, 0, 60) || die "$!";
+ print "read : '$buff'\n";
+
+ # the buffer of shmread is zero-character end-padded.
+ substr($buff, index($buff, "\0")) = '';
+ print "un" unless $buff eq $message;
+ print "swell\n";
+
+ print "deleting shm $id\n";
+ shmctl($id, IPC_RMID, 0) || die "$!";
+
+Here's an example of a semaphore:
+
+ use IPC::SysV qw(IPC_CREAT);
+
+ $IPC_KEY = 1234;
+ $id = semget($IPC_KEY, 10, 0666 | IPC_CREAT ) // die "$!";
+ print "shm key $id\n";
+
+Put this code in a separate file to be run in more than one process.
+Call the file F<take>:
+
+ # create a semaphore
+
+ $IPC_KEY = 1234;
+ $id = semget($IPC_KEY, 0 , 0 );
+ die if !defined($id);
+
+ $semnum = 0;
+ $semflag = 0;
+
+ # 'take' semaphore
+ # wait for semaphore to be zero
+ $semop = 0;
+ $opstring1 = pack("s!s!s!", $semnum, $semop, $semflag);
+
+ # Increment the semaphore count
+ $semop = 1;
+ $opstring2 = pack("s!s!s!", $semnum, $semop, $semflag);
+ $opstring = $opstring1 . $opstring2;
+
+ semop($id,$opstring) || die "$!";
+
+Put this code in a separate file to be run in more than one process.
+Call this file F<give>:
+
+ # 'give' the semaphore
+ # run this in the original process and you will see
+ # that the second process continues
+
+ $IPC_KEY = 1234;
+ $id = semget($IPC_KEY, 0, 0);
+ die if !defined($id);
+
+ $semnum = 0;
+ $semflag = 0;
+
+ # Decrement the semaphore count
+ $semop = -1;
+ $opstring = pack("s!s!s!", $semnum, $semop, $semflag);
+
+ semop($id,$opstring) || die "$!";
+
+The SysV IPC code above was written long ago, and it's definitely
+clunky looking. For a more modern look, see the IPC::SysV module
+which is included with Perl starting from Perl 5.005.
+
+A small example demonstrating SysV message queues:
+
+ use IPC::SysV qw(IPC_PRIVATE IPC_RMID IPC_CREAT S_IRUSR S_IWUSR);
+
+ my $id = msgget(IPC_PRIVATE, IPC_CREAT | S_IRUSR | S_IWUSR);
+
+ my $sent = "message";
+ my $type_sent = 1234;
+ my $rcvd;
+ my $type_rcvd;
+
+ if (defined $id) {
+ if (msgsnd($id, pack("l! a*", $type_sent, $sent), 0)) {
+ if (msgrcv($id, $rcvd, 60, 0, 0)) {
+ ($type_rcvd, $rcvd) = unpack("l! a*", $rcvd);
+ if ($rcvd eq $sent) {
+ print "okay\n";
+ } else {
+ print "not okay\n";
+ }
+ } else {
+ die "# msgrcv failed\n";
+ }
+ } else {
+ die "# msgsnd failed\n";
+ }
+ msgctl($id, IPC_RMID, 0) || die "# msgctl failed: $!\n";
+ } else {
+ die "# msgget failed\n";
+ }
+
+=head1 NOTES
+
+Most of these routines quietly but politely return C<undef> when they
+fail instead of causing your program to die right then and there due to
+an uncaught exception. (Actually, some of the new I<Socket> conversion
+functions croak() on bad arguments.) It is therefore essential to
+check return values from these functions. Always begin your socket
+programs this way for optimal success, and don't forget to add B<-T>
+taint checking flag to the #! line for servers:
+
+ #!/usr/bin/perl -Tw
+ use strict;
+ use sigtrap;
+ use Socket;
+
+=head1 BUGS
+
+All these routines create system-specific portability problems. As noted
+elsewhere, Perl is at the mercy of your C libraries for much of its system
+behaviour. It's probably safest to assume broken SysV semantics for
+signals and to stick with simple TCP and UDP socket operations; e.g., don't
+try to pass open file descriptors over a local UDP datagram socket if you
+want your code to stand a chance of being portable.
+
+=head1 AUTHOR
+
+Tom Christiansen, with occasional vestiges of Larry Wall's original
+version and suggestions from the Perl Porters.
+
+=head1 SEE ALSO
+
+There's a lot more to networking than this, but this should get you
+started.
+
+For intrepid programmers, the indispensable textbook is I<Unix
+Network Programming, 2nd Edition, Volume 1> by W. Richard Stevens
+(published by Prentice-Hall). Note that most books on networking
+address the subject from the perspective of a C programmer; translation
+to Perl is left as an exercise for the reader.
+
+The IO::Socket(3) manpage describes the object library, and the Socket(3)
+manpage describes the low-level interface to sockets. Besides the obvious
+functions in L<perlfunc>, you should also check out the F<modules> file
+at your nearest CPAN site. (See L<perlmodlib> or best yet, the F<Perl
+FAQ> for a description of what CPAN is and where to get it.)
+
+Section 5 of the F<modules> file is devoted to "Networking, Device Control
+(modems), and Interprocess Communication", and contains numerous unbundled
+modules numerous networking modules, Chat and Expect operations, CGI
+programming, DCE, FTP, IPC, NNTP, Proxy, Ptty, RPC, SNMP, SMTP, Telnet,
+Threads, and ToolTalk--just to name a few.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlirix.pod b/Master/tlpkg/tlperl/lib/pods/perlirix.pod
new file mode 100644
index 00000000000..911a2514b3a
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlirix.pod
@@ -0,0 +1,137 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.irix - Perl version 5 on Irix systems
+
+=head1 DESCRIPTION
+
+This document describes various features of Irix that will affect how Perl
+version 5 (hereafter just Perl) is compiled and/or runs.
+
+=head2 Building 32-bit Perl in Irix
+
+Use
+
+ sh Configure -Dcc='cc -n32'
+
+to compile Perl 32-bit. Don't bother with -n32 unless you have 7.1
+or later compilers (use cc -version to check).
+
+(Building 'cc -n32' is the default.)
+
+=head2 Building 64-bit Perl in Irix
+
+Use
+
+ sh Configure -Dcc='cc -64' -Duse64bitint
+
+This requires require a 64-bit MIPS CPU (R8000, R10000, ...)
+
+You can also use
+
+ sh Configure -Dcc='cc -64' -Duse64bitall
+
+but that makes no difference compared with the -Duse64bitint because
+of the C<cc -64>.
+
+You can also do
+
+ sh Configure -Dcc='cc -n32' -Duse64bitint
+
+to use long longs for the 64-bit integer type, in case you don't
+have a 64-bit CPU.
+
+If you are using gcc, just
+
+ sh Configure -Dcc=gcc -Duse64bitint
+
+should be enough, the Configure should automatically probe for the
+correct 64-bit settings.
+
+=head2 About Compiler Versions of Irix
+
+Some Irix cc versions, e.g. 7.3.1.1m (try cc -version) have been known
+to have issues (coredumps) when compiling perl.c. If you've used
+-OPT:fast_io=ON and this happens, try removing it. If that fails, or
+you didn't use that, then try adjusting other optimization options
+(-LNO, -INLINE, -O3 to -O2, etcetera). The compiler bug has been
+reported to SGI. (Allen Smith <easmith@beatrice.rutgers.edu>)
+
+=head2 Linker Problems in Irix
+
+If you get complaints about so_locations then search in the file
+hints/irix_6.sh for "lddflags" and do the suggested adjustments.
+(David Billinghurst <David.Billinghurst@riotinto.com.au>)
+
+=head2 Malloc in Irix
+
+Do not try to use Perl's malloc, this will lead into very mysterious
+errors (especially with -Duse64bitall).
+
+=head2 Building with threads in Irix
+
+Run Configure with -Duseithreads which will configure Perl with
+the Perl 5.8.0 "interpreter threads", see L<threads>.
+
+For Irix 6.2 with perl threads, you have to have the following
+patches installed:
+
+ 1404 Irix 6.2 Posix 1003.1b man pages
+ 1645 Irix 6.2 & 6.3 POSIX header file updates
+ 2000 Irix 6.2 Posix 1003.1b support modules
+ 2254 Pthread library fixes
+ 2401 6.2 all platform kernel rollup
+
+B<IMPORTANT>: Without patch 2401, a kernel bug in Irix 6.2 will cause
+your machine to panic and crash when running threaded perl. Irix 6.3
+and later are okay.
+
+ Thanks to Hannu Napari <Hannu.Napari@hut.fi> for the IRIX
+ pthreads patches information.
+
+=head2 Irix 5.3
+
+While running Configure and when building, you are likely to get
+quite a few of these warnings:
+
+ ld:
+ The shared object /usr/lib/libm.so did not resolve any symbols.
+ You may want to remove it from your link line.
+
+Ignore them: in IRIX 5.3 there is no way to quieten ld about this.
+
+During compilation you will see this warning from toke.c:
+
+ uopt: Warning: Perl_yylex: this procedure not optimized because it
+ exceeds size threshold; to optimize this procedure, use -Olimit option
+ with value >= 4252.
+
+Ignore the warning.
+
+In IRIX 5.3 and with Perl 5.8.1 (Perl 5.8.0 didn't compile in IRIX 5.3)
+the following failures are known.
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ --------------------------------------------------------------------------
+ ../ext/List/Util/t/shuffle.t 0 139 ?? ?? % ??
+ ../lib/Math/Trig.t 255 65280 29 12 41.38% 24-29
+ ../lib/sort.t 0 138 119 72 60.50% 48-119
+ 56 tests and 474 subtests skipped.
+ Failed 3/811 test scripts, 99.63% okay. 78/75813 subtests failed, 99.90% okay.
+
+They are suspected to be compiler errors (at least the shuffle.t
+failure is known from some IRIX 6 setups) and math library errors
+(the Trig.t failure), but since IRIX 5 is long since end-of-lifed,
+further fixes for the IRIX are unlikely. If you can get gcc for 5.3,
+you could try that, too, since gcc in IRIX 6 is a known workaround for
+at least the shuffle.t and sort.t failures.
+
+=head1 AUTHOR
+
+Jarkko Hietaniemi <jhi@iki.fi>
+
+Please report any errors, updates, or suggestions to F<perlbug@perl.org>.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perljp.pod b/Master/tlpkg/tlperl/lib/pods/perljp.pod
new file mode 100644
index 00000000000..6f022bbdbe1
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perljp.pod
@@ -0,0 +1,192 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+The following documentation is written in euc-jp encoding.
+
+=encoding euc-jp
+
+=head1 NAME
+
+perljp - ÆüËܸì Perl ¥¬¥¤¥É
+
+=head1 ÀâÌÀ
+
+Perl ¤ÎÀ¤³¦¤Ø¤è¤¦¤³¤½!
+
+Perl 5.8.0 ¤è¤ê¡¢Unicode¥µ¥Ý¡¼¥È¤¬ÂçÉý¤Ë¶¯²½¤µ¤ì¡¢¤½¤Î·ë²Ì¥é¥Æ¥óʸ»ú°Ê³°¤Îʸ»ú¥³¡¼¥É¤Î¥µ¥Ý¡¼¥È¤¬ CJK (Ãæ¹ñ¸ì¡¢ÆüËܸ졢¥Ï¥ó¥°¥ë)¤ò´Þ¤á¤Æ²Ã¤ï¤ê¤Þ¤·¤¿¡£Unicode¤ÏÀ¤³¦Ãæ¤Îʸ»ú¤ò°ì¤Ä¤Îʸ»ú¥³¡¼¥É¤Ç°·¤¦¤³¤È¤òÌܻؤ·¤¿É¸½àµ¬³Ê¤Ç¤¢¤ê¡¢Å줫¤éÀ¾¡¢¤Ï¤¿¤Þ¤¿¤½¤Î´Ö¤Îʸ»ú¡Ê¥®¥ê¥·¥ãʸ»ú¡¢¥­¥ê¡¼¥ëʸ»ú¡¢¥¢¥é¥Ó¥¢Ê¸»ú¡¢¥Ø¥Ö¥é¥¤Ê¸»ú¡¢¥Ç¥£¡¼¥ô¥¡¥Ê¥¬¡¼¥êʸ»ú¡¢¤Ê¤É¤Ê¤É¡Ë¤ä¡¢¤³¤ì¤Þ¤Ç¤ÏOS¥Ù¥ó¥À¡¼¤¬Æȼ«¤ËÄê¤á¤Æ¤¤¤¿Ê¸»ú(PC¤ª¤è¤ÓMacintosh)¤¬¤¹¤Ç¤Ë´Þ¤Þ¤ì¤Æ¤¤¤Þ¤¹¡£
+
+Perl ¼«¿È¤Ï Unicode ¤ÇÆ°ºî¤·¤Þ¤¹¡£Perl ¥¹¥¯¥ê¥×¥ÈÆâ¤Îʸ»úÎó¥ê¥Æ¥é¥ë¤äÀµµ¬É½¸½¤Ï Unicode ¤òÁ°Äó¤È¤·¤Æ¤¤¤Þ¤¹¡£¤½¤·¤ÆÆþ½ÐÎϤΤ¿¤á¤Ë¤Ï¡¢¤³¤ì¤Þ¤Ç»È¤ï¤ì¤Æ¤­¤¿¤µ¤Þ¤¶¤Þ¤Êʸ»ú¥³¡¼¥É¤ËÂбþ¤¹¤ë¥â¥¸¥å¡¼¥ë¡¢¡Ö Encode ¡×¤¬É¸½àÁõÈ÷¤µ¤ì¤Æ¤ª¤ê¡¢Unicode ¤È¤³¤ì¤é¤Îʸ»ú¥³¡¼¥É¤ÎÁê¸ßÊÑ´¹¤â´Êñ¤Ë¹Ô¤¨¤ë¤è¤¦¤Ë¤Ê¤Ã¤Æ¤¤¤Þ¤¹¡£
+
+¸½»þÅÀ¤Ç Encode ¤¬¥µ¥Ý¡¼¥È¤¹¤ëʸ»ú¥³¡¼¥É¤Ï°Ê²¼¤Î¤È¤ª¤ê¤Ç¤¹¡£
+
+ 7bit-jis AdobeStandardEncoding AdobeSymbol AdobeZdingbat
+ ascii big5 big5-hkscs cp1006
+ cp1026 cp1047 cp1250 cp1251
+ cp1252 cp1253 cp1254 cp1255
+ cp1256 cp1257 cp1258 cp37
+ cp424 cp437 cp500 cp737
+ cp775 cp850 cp852 cp855
+ cp856 cp857 cp860 cp861
+ cp862 cp863 cp864 cp865
+ cp866 cp869 cp874 cp875
+ cp932 cp936 cp949 cp950
+ dingbats euc-cn euc-jp euc-kr
+ gb12345-raw gb2312-raw gsm0338 hp-roman8
+ hz iso-2022-jp iso-2022-jp-1 iso-8859-1
+ iso-8859-10 iso-8859-11 iso-8859-13 iso-8859-14
+ iso-8859-15 iso-8859-16 iso-8859-2 iso-8859-3
+ iso-8859-4 iso-8859-5 iso-8859-6 iso-8859-7
+ iso-8859-8 iso-8859-9 iso-ir-165 jis0201-raw
+ jis0208-raw jis0212-raw johab koi8-f
+ koi8-r koi8-u ksc5601-raw MacArabic
+ MacCentralEurRoman MacChineseSimp MacChineseTrad MacCroatian
+ MacCyrillic MacDingbats MacFarsi MacGreek
+ MacHebrew MacIcelandic MacJapanese MacKorean
+ MacRoman MacRomanian MacRumanian MacSami
+ MacSymbol MacThai MacTurkish MacUkrainian
+ nextstep posix-bc shiftjis symbol
+ UCS-2BE UCS-2LE UTF-16 UTF-16BE
+ UTF-16LE UTF-32 UTF-32BE UTF-32LE
+ utf8 viscii
+
+(Á´114¼ïÎà)
+
+Î㤨¤Ð¡¢Ê¸»ú¥³¡¼¥ÉFOO¤Î¥Õ¥¡¥¤¥ë¤òUTF-8¤ËÊÑ´¹¤¹¤ë¤Ë¤Ï¡¢°Ê²¼¤Î¤è¤¦¤Ë¤·¤Þ¤¹¡£
+
+ perl -Mencoding=FOO,STDOUT,utf8 -pe1 < file.FOO > file.utf8
+
+¤Þ¤¿¡¢Perl¤Ë¤Ï¡¢Á´Éô¤¬Perl¤Ç½ñ¤«¤ì¤¿Ê¸»ú¥³¡¼¥ÉÊÑ´¹¥æ¡¼¥Æ¥£¥ê¥Æ¥£¡¢piconv¤âÉÕ°¤·¤Æ¤¤¤ë¤Î¤Ç¡¢°Ê²¼¤Î¤è¤¦¤Ë¤¹¤ë¤³¤È¤â¤Ç¤­¤Þ¤¹¡£
+
+ piconv -f FOO -t utf8 < file.FOO > file.utf8
+ piconv -f utf8 -t FOO < file.utf8 > file.FOO
+
+=head2 About (jcode.pl|Jcode.pm|JPerl)
+
+5.8°ÊÁ°¤Î¡¢¥¹¥¯¥ê¥×¥È¤¬EUC-JP¤Ç¤¢¤ì¤Ð¥ê¥Æ¥é¥ë¤À¤±¤Ï°·¤¦¤³¤È¤¬¤Ç¤­¤Þ¤·¤¿¡£¤Þ¤¿¡¢Æþ½ÐÎϤò°·¤¦¥â¥¸¥å¡¼¥ë¤È¤·¤Æ¤ÏJcode.pm¤¬( http://openlab.ring.gr.jp/Jcode/ )¡¢perl4ÍѤΥ桼¥Æ¥£¥ê¥Æ¥£¤È¤·¤Æ¤Ïjcode.pl¤¬¤½¤ì¤¾¤ì¸ºß¤·¡¢ÆüËܸì¤Î°·¤¨¤ëCGI¤Ç¤è¤¯ÍøÍѤµ¤ì¤Æ¤¤¤ë¤³¤È¤ò¸æ¸¤¸¤ÎÊý¤â¾¯¤Ê¤¯¤Ê¤¤¤«¤È»×¤ï¤ì¤Þ¤¹¡£¤¿¤À¤·¡¢ÆüËܸì¤Ë¤è¤ëÀµµ¬É½¸½¤ò¤¦¤Þ¤¯°·¤¦¤³¤È¤ÏÉÔ²Äǽ¤Ç¤·¤¿¡£
+
+5.005°ÊÁ°¤ÎPerl¤Ë¤Ï¡¢ÆüËܸì¤ËÆò½¤·¤¿¥í¡¼¥«¥é¥¤¥ºÈÇ¡¢Jperl¤¬Â¸ºß¤·¤Þ¤·¤¿( http://homepage2.nifty.com/kipp/perl/jperl/index.html )¡£¤Þ¤¿¡¢Mac OS 9.x/ClassicÍѤÎPerl¡¢MacPerl¤ÎÆüËܸìÈǤâMacJPerl¤È¤·¤Æ¸ºß¤·¤Æ¤Þ¤·¤¿¡£( http://habilis.net/macjperl/ ).¤³¤ì¤é¤Ç¤Ïʸ»ú¥³¡¼¥É¤È¤·¤ÆEUC-JP¤Ë²Ã¤¨Shift_JIS¤â¤½¤Î¤Þ¤Þ°·¤¦¤³¤È¤¬¤Ç¤­¡¢¤Þ¤¿ÆüËܸì¤Ë¤è¤ëÀµµ¬É½¸½¤ò°·¤¦¤³¤È¤â²Äǽ¤Ç¤·¤¿¡£
+
+Perl5.8¤Ç¤Ï¡¢¤³¤ì¤é¤Îµ¡Ç½¤¬¤¹¤Ù¤ÆPerlËÜÂΤÀ¤±¤Ç¼Â¸½¤Ç¤­¤ë¾å¤Ë¡¢ÆüËܸì¤Î¤ß¤Ê¤é¤º¾åµ­114¤Îʸ»ú¥³¡¼¥É¤ò¤¹¤Ù¤Æ¡¢¤·¤«¤âƱ»þ¤Ë°·¤¦¤³¤È¤¬¤Ç¤­¤Þ¤¹¡£¤µ¤é¤Ë¡¢CPAN¤Ê¤É¤«¤é¿·¤·¤¤Ê¸»ú¥³¡¼¥ÉÍѤΥ⥸¥å¡¼¥ë¤òÆþ¼ê¤¹¤ë¤³¤È¤â´Êñ¤Ë¤Ç¤­¤ë¤è¤¦¤Ë¤Ê¤Ã¤Æ¤¤¤Þ¤¹¡£
+
+=over 4
+
+=item *
+
+Æþ½ÐÎÏ
+
+°Ê²¼¤ÎÎã¤Ï¤¤¤Å¤ì¤âShift_JIS¤ÎÆþÎϤòEUC-JP¤ËÊÑ´¹¤·¤Æ½ÐÎϤ·¤Þ¤¹¡£
+
+ # jcode.pl
+ require "jcode.pl";
+ while(<>){
+ jcode::convert(*_, 'euc', 'sjis');
+ print;
+ }
+ # Jcode.pm
+ use Jcode;
+ while(<>){
+ print Jcode->new($_, 'sjis')->euc;
+ }
+ # Perl 5.8
+ use Encode;
+ while(<>){
+ from_to($_, 'shiftjis', 'euc-jp');
+ print;
+ }
+ # Perl 5.8 - encoding ¤òÍøÍѤ·¤Æ
+ use encoding 'euc-jp', STDIN => 'shiftjis';
+ while(<>){
+ print;
+ }
+
+=item *
+
+Jperl ¸ß´¹¥¹¥¯¥ê¥×¥È
+
+ ¤¤¤ï¤æ¤ë"shebang"¤òÊѹ¹¤¹¤ë¤À¤±¤Ç¡¢JperlÍѤÎscript¤Î¤Û¤È¤ó¤É¤ÏÊѹ¹¤Ê¤·¤ËÍøÍѲÄǽ¤À¤È»×¤ï¤ì¤Þ¤¹¡£
+
+ #!/path/to/jperl
+ ¢­
+ #!/path/to/perl -Mencoding=euc-jp
+
+ ¾Ü¤·¤¯¤Ï perldoc encoding ¤ò»²¾È¤·¤Æ¤¯¤À¤µ¤¤¡£
+
+=back
+
+=head2 ¤µ¤é¤Ë¾Ü¤·¤¯
+
+Perl¤Ë¤ÏËÄÂç¤Ê»ñÎÁ¤¬ÉÕ°¤·¤Æ¤ª¤ê¡¢Perl¤Î¿·µ¡Ç½¤äUnicode¥µ¥Ý¡¼¥È¡¢¤½¤·¤ÆEncode¥â¥¸¥å¡¼¥ë¤Î»ÈÍÑË¡¤Ê¤É¤¬ºÙ¤«¤¯ÌÖÍ夵¤ì¤Æ¤¤¤Þ¤¹¡Ê»ÄÇ°¤Ê¤¬¤é¡¢¤Û¤È¤ó¤É±Ñ¸ì¤Ç¤Ï¤¢¤ê¤Þ¤¹¤¬¡Ë¡£°Ê²¼¤Î¥³¥Þ¥ó¥É¤Ç¤½¤ì¤é¤Î°ìÉô¤ò±ÜÍ÷¤¹¤ë¤³¤È¤¬²Äǽ¤Ç¤¹¡£
+
+ perldoc perlunicode # Perl¤ÎUnicode¥µ¥Ý¡¼¥ÈÁ´ÈÌ
+ perldoc Encode # Encode¥â¥¸¥å¡¼¥ë¤Ë´Ø¤·¤Æ
+ perldoc Encode::JP # ¤¦¤ÁÆüËܸìʸ»ú¥³¡¼¥É¤Ë´Ø¤·¤Æ
+
+=head2 PerlÁ´È̤˴ؤ¹¤ë URL
+
+=over 4
+
+=item L<http://www.perl.com/>
+
+Perl ¥Û¡¼¥à¥Ú¡¼¥¸ (O'Reilly and Associates)
+
+=item L<http://www.cpan.org/>
+
+CPAN (Comprehensive Perl Archive Network)
+
+=item L<http://lists.perl.org/>
+
+Perl ¥á¡¼¥ê¥ó¥°¥ê¥¹¥È½¸
+
+=back
+
+=head2 Perl¤Î½¤ÆÀ¤ËÌòΩ¤Ä URL
+
+=over 4
+
+=item L<http://www.oreilly.com.tw/>
+
+O'Reilly ¼Ò¤ÎPerl´ØÏ¢½ñÀÒ(ÈËÂλúÃæ¹ñ¸ì)
+
+=item L<http://www.oreilly.com.cn/>
+
+O'Reilly ¼Ò¤ÎPerl´ØÏ¢½ñÀÒ(´ÊÂλúÃæ¹ñ¸ì)
+
+=item L<http://www.oreilly.co.jp/catalog/>
+
+¥ª¥é¥¤¥ê¡¼¼Ò¤ÎPerl´ØÏ¢½ñÀÒ(ÆüËܸì)
+
+=back
+
+=head2 Perl ¥æ¡¼¥¶¡¼¥°¥ë¡¼¥×
+
+=over 4
+
+=item L<http://www.pm.org/groups/asia.html>
+
+=back
+
+=head2 Unicode´ØÏ¢¤ÎURL
+
+=over 4
+
+=item L<http://www.unicode.org/>
+
+Unicode ¥³¥ó¥½¡¼¥·¥¢¥à (Unicodeµ¬³Ê¤ÎÁªÄêÃÄÂÎ)
+
+=item L<http://www.cl.cam.ac.uk/%7Emgk25/unicode.html>
+
+UTF-8 and Unicode FAQ for Unix/Linux
+
+=item L<http://kldp.org/Translations/html/UTF8-Unicode-KLDP/UTF8-Unicode-KLDP.html>
+
+UTF-8 and Unicode FAQ for Unix/Linux (¥Ï¥ó¥°¥ëÌõ)
+
+=back
+
+=head1 AUTHORS
+
+Jarkko Hietaniemi E<lt>jhi@iki.fiE<gt>
+Dan Kogai (¾®»ô¡¡ÃÆ) E<lt>dankogai@dan.co.jpE<gt>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlko.pod b/Master/tlpkg/tlperl/lib/pods/perlko.pod
new file mode 100644
index 00000000000..611ed7c3fde
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlko.pod
@@ -0,0 +1,207 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+This file is in Korean encoded in EUC-KR.
+
+ÀÌ ¹®¼­¸¦ perldocÀ» ½á¼­ º¸Áö ¾Ê°í Á÷Á¢ º¸´Â °æ¿ì¿¡´Â °¢ ºÎºÐÀÇ
+¿ªÇÒÀ» Ç¥½ÃÇϱâ À§ÇØ ¾²ÀÎ =head, =item, 'L' µîÀº ¹«½ÃÇϽʽÿÀ.
+ÀÌ ¹®¼­´Â µû·Î perldocÀ» ¾²Áö ¾Ê°í º¸´õ¶óµµ Àдµ¥ º° ÁöÀåÀÌ
+¾ø´Â POD Çü½ÄÀ¸·Î Â¥¿© ÀÖ½À´Ï´Ù. ´õ ÀÚ¼¼ÇÑ °ÍÀº perlpod
+¸Å´º¾óÀ» Âü°íÇϽʽÿÀ.
+
+=encoding euc-kr
+
+=head1 NAME
+
+perlko - Perl°ú Çѱ¹¾î ÀÎÄÚµù
+
+=head1 DESCRIPTION
+
+PerlÀÇ ¼¼°è¿¡ ¿À½Å °ÍÀ» ȯ¿µÇÕ´Ï´Ù !
+
+
+PerlÀº 5.8.0ÆǺÎÅÍ À¯´ÏÄÚµå/ISO 10646¿¡ ´ëÇÑ ±¤¹üÀ§ÇÑ Áö¿øÀ» ÇÕ´Ï´Ù.
+À¯´ÏÄÚµå Áö¿øÀÇ ÀÏȯÀ¸·Î ÇÑÁßÀÏÀ» ºñ·ÔÇÑ ¼¼°è °¢±¹¿¡¼­
+À¯´ÏÄÚµå ÀÌÀü¿¡ ¾²°í ÀÖ¾ú°í Áö±Ýµµ ³Î¸® ¾²ÀÌ°í ÀÖ´Â ¼ö¸¹Àº ÀÎÄÚµùÀ»
+Áö¿øÇÕ´Ï´Ù. À¯´ÏÄÚµå´Â Àü ¼¼°è¿¡¼­ ¾²ÀÌ´Â ¸ðµç ¾ð¾î¸¦ À§ÇÑ Ç¥±â ü°è -
+À¯·´ÀÇ ¶óƾ ¾ËÆĺª, Å°¸± ¾ËÆĺª, ±×¸®½º ¾ËÆĺª, Àεµ¿Í µ¿³² ¾Æ½Ã¾ÆÀÇ
+ºê¶ó¹Ì °è¿­ ½ºÅ©¸³Æ®, ¾Æ¶ø ¹®ÀÚ, È÷ºê¸® ¹®ÀÚ, ÇÑÁßÀÏÀÇ ÇÑÀÚ, Çѱ¹¾îÀÇ ÇѱÛ,
+ÀϺ»¾îÀÇ °¡³ª, ºÏ¹Ì Àεð¾ÈÀÇ Ç¥±â ü°è µî-¸¦ ¼ö¿ëÇÏ´Â °ÍÀ» ¸ñÇ¥·Î ÇÏ°í
+Àֱ⠶§¹®¿¡ ±âÁ¸¿¡ ¾²ÀÌ´ø °¢ ¾ð¾î ¹× ±¹°¡ ±×¸®°í ¿î¿µ ü°è¿¡ °íÀ¯ÇÑ
+¹®ÀÚ ÁýÇÕ°ú ÀÎÄÚµù¿¡ ¾µ ¼ö ÀÖ´Â ¸ðµç ±ÛÀÚ´Â ¹°·ÐÀÌ°í ±âÁ¸ ¹®ÀÚ ÁýÇÕ¿¡¼­
+Áö¿øÇÏ°í ÀÖÁö ¾Ê´ø ¾ÆÁÖ ¸¹Àº ±ÛÀÚ¸¦ Æ÷ÇÔÇÏ°í ÀÖ½À´Ï´Ù.
+
+
+PerlÀº ³»ºÎÀûÀ¸·Î À¯´ÏÄڵ带 ¹®ÀÚ Ç¥ÇöÀ» À§ÇØ »ç¿ëÇÕ´Ï´Ù. º¸´Ù ±¸Ã¼ÀûÀ¸·Î
+¸»Çϸé Perl ½ºÅ©¸³Æ® ¾È¿¡¼­ UTF-8 ¹®ÀÚ¿­À» ¾µ ¼ö ÀÖ°í,
+°¢Á¾ ÇÔ¼ö¿Í ¿¬»êÀÚ(¿¹¸¦ µé¾î, Á¤±Ô½Ä, index, substr)°¡ ¹ÙÀÌÆ® ´ÜÀ§
+´ë½Å À¯´ÏÄÚµå ±ÛÀÚ ´ÜÀ§·Î µ¿ÀÛÇÕ´Ï´Ù. (´õ ÀÚ¼¼ÇÑ °ÍÀº
+perlunicode ¸Å´º¾óÀ» Âü°íÇϽʽÿÀ.) À¯´ÏÄڵ尡 ³Î¸® º¸±ÞµÇ±â Àü¿¡
+³Î¸® ¾²ÀÌ°í ÀÖ¾ú°í, ¿©ÀüÈ÷ ³Î¸® ¾²ÀÌ°í ÀÖ´Â °¢±¹/°¢ ¾ð¾îº° ÀÎÄÚµùÀ¸·Î
+ÀÔÃâ·ÂÀ» ÇÏ°í À̵é ÀÎÄÚµùÀ¸·Î µÈ µ¥ÀÌÅÍ¿Í ¹®¼­¸¦ ´Ù·ç´Â °ÍÀ» µ½±â À§ÇØ
+'Encode'°¡ ¾²¿´½À´Ï´Ù. ¹«¾ùº¸´Ù 'Encode'¸¦ ½á¼­ ¼ö¸¹Àº ÀÎÄÚµù »çÀÌÀÇ
+º¯È¯À» ½±°Ô ÇÒ ¼ö ÀÖ½À´Ï´Ù.
+
+'Encode'´Â ´ÙÀ½°ú °°Àº Çѱ¹¾î ÀÎÄÚµùÀ» Áö¿øÇÕ´Ï´Ù.
+
+=over 4
+
+=item euc-kr
+
+ US-ASCII¿Í KS X 1001À» °°ÀÌ ¾²´Â ¸ÖƼ¹ÙÀÌÆ® ÀÎÄÚµù (ÈçÈ÷ ¿Ï¼ºÇüÀ̶ó°í
+ ºÒ¸².) KS X 2901°ú RFC 1557 Âü°í.
+
+=item cp949
+
+ MS-Windows 9x/ME¿¡¼­ ¾²ÀÌ´Â È®Àå ¿Ï¼ºÇü. euc-kr¿¡ 8,822ÀÚÀÇ
+ ÇÑ±Û À½ÀýÀ» ´õÇÑ °ÍÀÓ. alias´Â uhc, windows-949, x-windows-949,
+ ks_c_5601-1987. ¸Ç ¸¶Áö¸· À̸§Àº ÀûÀýÇÏÁö ¾ÊÀº À̸§ÀÌÁö¸¸, Microsoft
+ Á¦Ç°¿¡¼­ CP949ÀÇ Àǹ̷Π¾²ÀÌ°í ÀÖÀ½.
+
+=item johab
+
+ KS X 1001:1998 ºÎ·Ï 3¿¡¼­ ±ÔÁ¤ÇÑ Á¶ÇÕÇü. ¹®ÀÚ ·¹ÆÛÅ丮´Â cp949¿Í
+ ¸¶Âù°¡Áö·Î US-ASCII¿Í KS X 1001¿¡ 8,822ÀÚÀÇ ÇÑ±Û À½ÀýÀ» ´õÇÑ °ÍÀÓ.
+ ÀÎÄÚµù ¹æ½ÄÀº ÀüÇô ´Ù¸§.
+
+=item iso-2022-kr
+
+ RFC 1557¿¡¼­ ±ÔÁ¤ÇÑ Çѱ¹¾î ÀÎÅÍ³Ý ¸ÞÀÏ ±³È¯¿ë ÀÎÄÚµùÀ¸·Î US-ASCII¿Í
+ KS X 1001À» ·¹ÆÛÅ丮·Î ÇÏ´Â Á¡¿¡¼­ euc-kr°ú °°Áö¸¸ ÀÎÄÚµù ¹æ½ÄÀÌ ´Ù¸§.
+ 1997-8³â °æ±îÁö ¾²¿´À¸³ª ´õ ÀÌ»ó ¸ÞÀÏ ±³È¯¿¡ ¾²ÀÌÁö ¾ÊÀ½.
+
+=item ksc5601-raw
+
+ KS X 1001(KS C 5601)À» GL(Áï, MSB¸¦ 0À¸·Î ÇÑ °æ¿ì) ¿¡ ³õ¾ÒÀ» ¶§ÀÇ
+ ÀÎÄÚµù. US-ASCII¿Í °áÇÕÇÏÁö ¾Ê°í ´Üµ¶À¸·Î ¾²ÀÌ´Â ÀÏÀº X11 µî¿¡¼­ ±Û²Ã
+ ÀÎÄÚµù (ksc5601.1987-0. '0'Àº GLÀ» ÀǹÌÇÔ.)À¸·Î ¾²ÀÌ´Â °ÍÀ» Á¦¿ÜÇÏ°í´Â
+ °ÅÀÇ ¾øÀ½. KS C 5601Àº 1997³â KS X 1001·Î À̸§À» ¹Ù²Ù¾úÀ½. 1998³â¿¡´Â µÎ
+ ±ÛÀÚ (À¯·ÎÈ­ ºÎÈ£¿Í µî·Ï »óÇ¥ ºÎÈ£)°¡ ´õÇØÁ³À½.
+
+=back
+
+ ¸î °¡Áö »ç¿ë ¿¹Á¦¸¦ ¾Æ·¡¿¡ º¸ÀÔ´Ï´Ù.
+
+¿¹¸¦ µé¾î, euc-kr ÀÎÄÚµùÀ¸·Î µÈ ÆÄÀÏÀ» UTF-8·Î º¯È¯ÇÏ·Á¸é ´ÙÀ½°ú
+°°ÀÌ ÇÏ¸é µË´Ï´Ù.
+
+
+ perl -Mencoding=euc-kr,STDOUT,utf8 -pe1 < file.euckr > file.utf8
+
+¿ªº¯È¯Àº ´ÙÀ½°ú °°ÀÌ ÇÒ ¼ö ÀÖ½À´Ï´Ù.
+
+ perl -Mencoding=utf8,STDOUT,euc-kr -pe1 < file.utf8 > file.euckr
+
+ ÀÌ·± º¯È¯À» Á»´õ Æí¸®ÇÏ°Ô ÇÒ ¼ö ÀÖµµ·Ï Encode ¸ðµâÀ» ½á¼­
+¼ø¼öÇÏ°Ô Perl·Î¸¸ ¾²ÀÎ piconv°¡ Perl¿¡ µé¾î ÀÖ½À´Ï´Ù.
+±× À̸§¿¡¼­ ¾Ë ¼ö ÀÖµíÀÌ piconv´Â Unix¿¡ ÀÖ´Â iconv¸¦
+¸ðµ¨·Î ÇÑ °ÍÀÔ´Ï´Ù. ±× »ç¿ë¹ýÀº ¾Æ·¡¿Í °°½À´Ï´Ù.
+
+ piconv -f euc-kr -t utf8 < file.euckr > file.utf8
+ piconv -f utf8 -t euc-kr < file.utf8 > file.euckr
+
+ ¶Ç, 'PerlIO::encoding' ¸ðµâÀ» ½á¼­ Çѱ¹¾î ÀÎÄÚµùÀ» ¾²¸é¼­ ±ÛÀÚ ´ÜÀ§
+(¹ÙÀÌÆ® ´ÜÀ§°¡ ¾Æ´Ï¶ó) 󸮸¦ ½±°Ô ÇÒ ¼ö ÀÖ½À´Ï´Ù.
+
+ #!/path/to/perl
+
+ use encoding 'euc-kr', STDIN => 'euc-kr',
+ STDOUT-> 'euc-kr', STDERR=>'euc-kr';
+
+ print length("°¡³ª"); # 2 (Å« µû¿ÈÇ¥´Â ±ÛÀÚ ´ÜÀ§ 󸮸¦ Áö½Ã)
+ print length('°¡³ª'); # 4 (ÀÛÀº µû¿ÈÇ¥´Â ¹ÙÀÌÆ® ´ÜÀ§ 󸮸¦ Áö½Ã)
+ print index("ÇÑ°­, ´ëµ¿°­", "¿°"); # -1 ('¿°'ÀÌ ¾øÀ½)
+ print index('ÇÑ°­, ´ëµ¿°­', '¿°'); # 7 (8¹ø°¿Í 9¹ø° ¹ÙÀÌÆ®°¡ '¿°'ÀÇ
+ Äڵ尪°ú ÀÏÄ¡ÇÔ.)
+
+
+=head2 ´õ ÀÚ¼¼È÷ ¾Ë°í ½ÍÀ¸¸é...
+
+ PerlÀ» ¼³Ä¡ÇÏ¸é ´ë´ÜÈ÷ ÀÚ¼¼ÇÑ ¹®¼­°¡ °°ÀÌ µû¶ó ¿À¸ç, ÀÌ ¹®¼­¸¦ ÅëÇØ
+Perl Àü¹Ý »Ó ¾Æ´Ï¶ó À¯´ÏÄÚµå Áö¿ø, EncodeÀÇ »ç¿ë¹ý µî¿¡ ¸¹Àº °ÍÀ»
+¹è¿ï ¼ö ÀÖ½À´Ï´Ù. ¾ÆÁ÷ ÀÌ ¹®¼­´Â ÇöÀç ¸ðµÎ ¿µ¾î·Î ¾²¿© ÀÖ½À´Ï´Ù.
+
+
+=head2 Perl °ü·Ã ÀÚ·á
+
+À§¿¡¼­ ¾ð±ÞÇÑ ¹®¼­ ¿Ü¿¡µµ ´ÙÀ½°ú °°Àº ÀÚ·á°¡ ÀÖ½À´Ï´Ù. ÀÌ ¸ñ·ÏÀº °áÄÚ
+¿ÏÀüÇÑ °ÍÀÌ ¾Æ´Ï°í ÀϺΠ´ëÇ¥ÀûÀÎ °Í¸¸ ¸ðÀº °ÍÀÔ´Ï´Ù.
+
+=over 4
+
+=item L<http://www.perl.com/>
+
+ O'ReillyÀÇ Perl À¥ ÆäÀÌÁö
+
+=item L<http://www.cpan.org/>
+
+ Comprehensive Perl Archive Network
+
+=item L<http://lists.perl.org/>
+
+ Perl ¸ÞÀϸµ ¸®½ºÆ®. ¸¹Àº ¸®½ºÆ® °¡¿îµ¥
+ perl-unicode¿¡¼­ 'Encode'¿¡ ´ëÇØ ³íÀÇÇÔ.
+
+=back
+
+=head2 PerlÀ» ´õ ±í°Ô °øºÎÇϴµ¥ µµ¿òÀ» ÁÙ ¼ö ÀÖ´Â Çѱ¹¾î °ü·Ã »çÀÌÆ®
+
+=over 4
+
+=item L<http://www.perl.or.kr/>
+
+ Perl Çѱ¹ »ç¿ëÀÚ ¸ðÀÓ
+
+=item L<news:han.comp.lang.perl/>
+
+ Çѱ¹¾î Perl ´º½º ±×·ì
+
+=item L<http://www.hanb.co.kr/search/searchResult.php?keyword=perl>
+
+ O'Reilly¿¡¼­ ³ª¿Â Çѱ¹¾î Perl ¼­Àû ¸ñ·Ï
+
+=item L<http://www.perlschool.net/>
+
+ Perl ±âÃÊ °­Á ¹× ¼Ò½º, ÃÖ±Ù µ¿Çâ, °ü·Ã ÇØ¿Ü »çÀÌÆ® ¸µÅ©
+
+=item L<http://www.perl.co.kr>
+
+ Perl¿¡ °ü·ÃµÈ CGI, DB, ¿¬µ¿ µî¿¡ ´ëÇÑ Á¤º¸ ¹× ´º½º Á¦°ø
+
+=back
+
+=head2 À¯´ÏÄÚµå ¹× Çѱ¹¾î ÀÎÄÚµù °ü·Ã ÀÚ·á
+
+=over 4
+
+=item L<http://www.unicode.org/>
+
+ À¯´ÏÄÚµå ÄÁ¼Ò½Ã¾ö.
+
+=item L<http://std.dkuug.dk/JTC1/SC2/WG2>
+
+±âº»ÀûÀ¸·Î Unicode¿Í °°Àº ISO Ç¥ÁØÀÎ ISO/IEC 10646 UCS(Universal
+Character Set)À» ¸¸µå´Â ISO/IEC JTC1/SC2/WG2ÀÇ À¥ ÆäÀÌÁö.
+
+=item L<http://www.cl.cam.ac.uk/~mgk25/unicode.html>
+
+ À¯´Ð½º/¸®´ª½º¿¡¼­ À¯´ÏÄÚµå¿Í UTF-8 »ç¿ë¿¡ ´ëÇÑ ¹®´äÁý(FAQ)
+
+=item L<http://kldp.org/Translations/html/UTF8-Unicode-KLDP/UTF8-Unicode-KLDP.html>
+
+ À¯´Ð½º/¸®´ª½º¿¡¼­ À¯´ÏÄÚµå¿Í UTF-8 »ç¿ë¿¡ ´ëÇÑ ¹®´äÁý(FAQ)ÀÇ Çѱ¹¾î ¹ø¿ª
+
+=back
+
+=head1 SEE ALSO
+
+L<Encode>, L<Encode::KR>, L<encoding>, L<perluniintro>, L<perlunicode>
+
+
+=head1 AUTHORS
+
+Jarkko Hietaniemi E<lt>jhi@iki.fiE<gt>
+½ÅÁ¤½Ä E<lt>jshin@mailaps.orgE<gt>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perllexwarn.pod b/Master/tlpkg/tlperl/lib/pods/perllexwarn.pod
new file mode 100644
index 00000000000..835914e4869
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perllexwarn.pod
@@ -0,0 +1,529 @@
+=head1 NAME
+X<warning, lexical> X<warnings> X<warning>
+
+perllexwarn - Perl Lexical Warnings
+
+=head1 DESCRIPTION
+
+The C<use warnings> pragma enables to control precisely what warnings are
+to be enabled in which parts of a Perl program. It's a more flexible
+alternative for both the command line flag B<-w> and the equivalent Perl
+variable, C<$^W>.
+
+This pragma works just like the C<strict> pragma.
+This means that the scope of the warning pragma is limited to the
+enclosing block. It also means that the pragma setting will not
+leak across files (via C<use>, C<require> or C<do>). This allows
+authors to independently define the degree of warning checks that will
+be applied to their module.
+
+By default, optional warnings are disabled, so any legacy code that
+doesn't attempt to control the warnings will work unchanged.
+
+All warnings are enabled in a block by either of these:
+
+ use warnings;
+ use warnings 'all';
+
+Similarly all warnings are disabled in a block by either of these:
+
+ no warnings;
+ no warnings 'all';
+
+For example, consider the code below:
+
+ use warnings;
+ my @a;
+ {
+ no warnings;
+ my $b = @a[0];
+ }
+ my $c = @a[0];
+
+The code in the enclosing block has warnings enabled, but the inner
+block has them disabled. In this case that means the assignment to the
+scalar C<$c> will trip the C<"Scalar value @a[0] better written as $a[0]">
+warning, but the assignment to the scalar C<$b> will not.
+
+=head2 Default Warnings and Optional Warnings
+
+Before the introduction of lexical warnings, Perl had two classes of
+warnings: mandatory and optional.
+
+As its name suggests, if your code tripped a mandatory warning, you
+would get a warning whether you wanted it or not.
+For example, the code below would always produce an C<"isn't numeric">
+warning about the "2:".
+
+ my $a = "2:" + 3;
+
+With the introduction of lexical warnings, mandatory warnings now become
+I<default> warnings. The difference is that although the previously
+mandatory warnings are still enabled by default, they can then be
+subsequently enabled or disabled with the lexical warning pragma. For
+example, in the code below, an C<"isn't numeric"> warning will only
+be reported for the C<$a> variable.
+
+ my $a = "2:" + 3;
+ no warnings;
+ my $b = "2:" + 3;
+
+Note that neither the B<-w> flag or the C<$^W> can be used to
+disable/enable default warnings. They are still mandatory in this case.
+
+=head2 What's wrong with B<-w> and C<$^W>
+
+Although very useful, the big problem with using B<-w> on the command
+line to enable warnings is that it is all or nothing. Take the typical
+scenario when you are writing a Perl program. Parts of the code you
+will write yourself, but it's very likely that you will make use of
+pre-written Perl modules. If you use the B<-w> flag in this case, you
+end up enabling warnings in pieces of code that you haven't written.
+
+Similarly, using C<$^W> to either disable or enable blocks of code is
+fundamentally flawed. For a start, say you want to disable warnings in
+a block of code. You might expect this to be enough to do the trick:
+
+ {
+ local ($^W) = 0;
+ my $a =+ 2;
+ my $b; chop $b;
+ }
+
+When this code is run with the B<-w> flag, a warning will be produced
+for the C<$a> line: C<"Reversed += operator">.
+
+The problem is that Perl has both compile-time and run-time warnings. To
+disable compile-time warnings you need to rewrite the code like this:
+
+ {
+ BEGIN { $^W = 0 }
+ my $a =+ 2;
+ my $b; chop $b;
+ }
+
+The other big problem with C<$^W> is the way you can inadvertently
+change the warning setting in unexpected places in your code. For example,
+when the code below is run (without the B<-w> flag), the second call
+to C<doit> will trip a C<"Use of uninitialized value"> warning, whereas
+the first will not.
+
+ sub doit
+ {
+ my $b; chop $b;
+ }
+
+ doit();
+
+ {
+ local ($^W) = 1;
+ doit()
+ }
+
+This is a side-effect of C<$^W> being dynamically scoped.
+
+Lexical warnings get around these limitations by allowing finer control
+over where warnings can or can't be tripped.
+
+=head2 Controlling Warnings from the Command Line
+
+There are three Command Line flags that can be used to control when
+warnings are (or aren't) produced:
+
+=over 5
+
+=item B<-w>
+X<-w>
+
+This is the existing flag. If the lexical warnings pragma is B<not>
+used in any of you code, or any of the modules that you use, this flag
+will enable warnings everywhere. See L<Backward Compatibility> for
+details of how this flag interacts with lexical warnings.
+
+=item B<-W>
+X<-W>
+
+If the B<-W> flag is used on the command line, it will enable all warnings
+throughout the program regardless of whether warnings were disabled
+locally using C<no warnings> or C<$^W =0>. This includes all files that get
+included via C<use>, C<require> or C<do>.
+Think of it as the Perl equivalent of the "lint" command.
+
+=item B<-X>
+X<-X>
+
+Does the exact opposite to the B<-W> flag, i.e. it disables all warnings.
+
+=back
+
+=head2 Backward Compatibility
+
+If you are used with working with a version of Perl prior to the
+introduction of lexically scoped warnings, or have code that uses both
+lexical warnings and C<$^W>, this section will describe how they interact.
+
+How Lexical Warnings interact with B<-w>/C<$^W>:
+
+=over 5
+
+=item 1.
+
+If none of the three command line flags (B<-w>, B<-W> or B<-X>) that
+control warnings is used and neither C<$^W> or the C<warnings> pragma
+are used, then default warnings will be enabled and optional warnings
+disabled.
+This means that legacy code that doesn't attempt to control the warnings
+will work unchanged.
+
+=item 2.
+
+The B<-w> flag just sets the global C<$^W> variable as in 5.005. This
+means that any legacy code that currently relies on manipulating C<$^W>
+to control warning behavior will still work as is.
+
+=item 3.
+
+Apart from now being a boolean, the C<$^W> variable operates in exactly
+the same horrible uncontrolled global way, except that it cannot
+disable/enable default warnings.
+
+=item 4.
+
+If a piece of code is under the control of the C<warnings> pragma,
+both the C<$^W> variable and the B<-w> flag will be ignored for the
+scope of the lexical warning.
+
+=item 5.
+
+The only way to override a lexical warnings setting is with the B<-W>
+or B<-X> command line flags.
+
+=back
+
+The combined effect of 3 & 4 is that it will allow code which uses
+the C<warnings> pragma to control the warning behavior of $^W-type
+code (using a C<local $^W=0>) if it really wants to, but not vice-versa.
+
+=head2 Category Hierarchy
+X<warning, categories>
+
+A hierarchy of "categories" have been defined to allow groups of warnings
+to be enabled/disabled in isolation.
+
+The current hierarchy is:
+
+ all -+
+ |
+ +- closure
+ |
+ +- deprecated
+ |
+ +- exiting
+ |
+ +- glob
+ |
+ +- io -----------+
+ | |
+ | +- closed
+ | |
+ | +- exec
+ | |
+ | +- layer
+ | |
+ | +- newline
+ | |
+ | +- pipe
+ | |
+ | +- unopened
+ |
+ +- imprecision
+ |
+ +- misc
+ |
+ +- numeric
+ |
+ +- once
+ |
+ +- overflow
+ |
+ +- pack
+ |
+ +- portable
+ |
+ +- recursion
+ |
+ +- redefine
+ |
+ +- regexp
+ |
+ +- severe -------+
+ | |
+ | +- debugging
+ | |
+ | +- inplace
+ | |
+ | +- internal
+ | |
+ | +- malloc
+ |
+ +- signal
+ |
+ +- substr
+ |
+ +- syntax -------+
+ | |
+ | +- ambiguous
+ | |
+ | +- bareword
+ | |
+ | +- digit
+ | |
+ | +- illegalproto
+ | |
+ | +- parenthesis
+ | |
+ | +- precedence
+ | |
+ | +- printf
+ | |
+ | +- prototype
+ | |
+ | +- qw
+ | |
+ | +- reserved
+ | |
+ | +- semicolon
+ |
+ +- taint
+ |
+ +- threads
+ |
+ +- uninitialized
+ |
+ +- unpack
+ |
+ +- untie
+ |
+ +- utf8
+ |
+ +- void
+
+Just like the "strict" pragma any of these categories can be combined
+
+ use warnings qw(void redefine);
+ no warnings qw(io syntax untie);
+
+Also like the "strict" pragma, if there is more than one instance of the
+C<warnings> pragma in a given scope the cumulative effect is additive.
+
+ use warnings qw(void); # only "void" warnings enabled
+ ...
+ use warnings qw(io); # only "void" & "io" warnings enabled
+ ...
+ no warnings qw(void); # only "io" warnings enabled
+
+To determine which category a specific warning has been assigned to see
+L<perldiag>.
+
+Note: In Perl 5.6.1, the lexical warnings category "deprecated" was a
+sub-category of the "syntax" category. It is now a top-level category
+in its own right.
+
+
+=head2 Fatal Warnings
+X<warning, fatal>
+
+The presence of the word "FATAL" in the category list will escalate any
+warnings detected from the categories specified in the lexical scope
+into fatal errors. In the code below, the use of C<time>, C<length>
+and C<join> can all produce a C<"Useless use of xxx in void context">
+warning.
+
+ use warnings;
+
+ time;
+
+ {
+ use warnings FATAL => qw(void);
+ length "abc";
+ }
+
+ join "", 1,2,3;
+
+ print "done\n";
+
+When run it produces this output
+
+ Useless use of time in void context at fatal line 3.
+ Useless use of length in void context at fatal line 7.
+
+The scope where C<length> is used has escalated the C<void> warnings
+category into a fatal error, so the program terminates immediately it
+encounters the warning.
+
+To explicitly turn off a "FATAL" warning you just disable the warning
+it is associated with. So, for example, to disable the "void" warning
+in the example above, either of these will do the trick:
+
+ no warnings qw(void);
+ no warnings FATAL => qw(void);
+
+If you want to downgrade a warning that has been escalated into a fatal
+error back to a normal warning, you can use the "NONFATAL" keyword. For
+example, the code below will promote all warnings into fatal errors,
+except for those in the "syntax" category.
+
+ use warnings FATAL => 'all', NONFATAL => 'syntax';
+
+=head2 Reporting Warnings from a Module
+X<warning, reporting> X<warning, registering>
+
+The C<warnings> pragma provides a number of functions that are useful for
+module authors. These are used when you want to report a module-specific
+warning to a calling module has enabled warnings via the C<warnings>
+pragma.
+
+Consider the module C<MyMod::Abc> below.
+
+ package MyMod::Abc;
+
+ use warnings::register;
+
+ sub open {
+ my $path = shift;
+ if ($path !~ m#^/#) {
+ warnings::warn("changing relative path to /var/abc")
+ if warnings::enabled();
+ $path = "/var/abc/$path";
+ }
+ }
+
+ 1;
+
+The call to C<warnings::register> will create a new warnings category
+called "MyMod::Abc", i.e. the new category name matches the current
+package name. The C<open> function in the module will display a warning
+message if it gets given a relative path as a parameter. This warnings
+will only be displayed if the code that uses C<MyMod::Abc> has actually
+enabled them with the C<warnings> pragma like below.
+
+ use MyMod::Abc;
+ use warnings 'MyMod::Abc';
+ ...
+ abc::open("../fred.txt");
+
+It is also possible to test whether the pre-defined warnings categories are
+set in the calling module with the C<warnings::enabled> function. Consider
+this snippet of code:
+
+ package MyMod::Abc;
+
+ sub open {
+ warnings::warnif("deprecated",
+ "open is deprecated, use new instead");
+ new(@_);
+ }
+
+ sub new
+ ...
+ 1;
+
+The function C<open> has been deprecated, so code has been included to
+display a warning message whenever the calling module has (at least) the
+"deprecated" warnings category enabled. Something like this, say.
+
+ use warnings 'deprecated';
+ use MyMod::Abc;
+ ...
+ MyMod::Abc::open($filename);
+
+Either the C<warnings::warn> or C<warnings::warnif> function should be
+used to actually display the warnings message. This is because they can
+make use of the feature that allows warnings to be escalated into fatal
+errors. So in this case
+
+ use MyMod::Abc;
+ use warnings FATAL => 'MyMod::Abc';
+ ...
+ MyMod::Abc::open('../fred.txt');
+
+the C<warnings::warnif> function will detect this and die after
+displaying the warning message.
+
+The three warnings functions, C<warnings::warn>, C<warnings::warnif>
+and C<warnings::enabled> can optionally take an object reference in place
+of a category name. In this case the functions will use the class name
+of the object as the warnings category.
+
+Consider this example:
+
+ package Original;
+
+ no warnings;
+ use warnings::register;
+
+ sub new
+ {
+ my $class = shift;
+ bless [], $class;
+ }
+
+ sub check
+ {
+ my $self = shift;
+ my $value = shift;
+
+ if ($value % 2 && warnings::enabled($self))
+ { warnings::warn($self, "Odd numbers are unsafe") }
+ }
+
+ sub doit
+ {
+ my $self = shift;
+ my $value = shift;
+ $self->check($value);
+ # ...
+ }
+
+ 1;
+
+ package Derived;
+
+ use warnings::register;
+ use Original;
+ our @ISA = qw( Original );
+ sub new
+ {
+ my $class = shift;
+ bless [], $class;
+ }
+
+
+ 1;
+
+The code below makes use of both modules, but it only enables warnings from
+C<Derived>.
+
+ use Original;
+ use Derived;
+ use warnings 'Derived';
+ my $a = Original->new();
+ $a->doit(1);
+ my $b = Derived->new();
+ $a->doit(1);
+
+When this code is run only the C<Derived> object, C<$b>, will generate
+a warning.
+
+ Odd numbers are unsafe at main.pl line 7
+
+Notice also that the warning is reported at the line where the object is first
+used.
+
+=head1 SEE ALSO
+
+L<warnings>, L<perldiag>.
+
+=head1 AUTHOR
+
+Paul Marquess
diff --git a/Master/tlpkg/tlperl/lib/pods/perllinux.pod b/Master/tlpkg/tlperl/lib/pods/perllinux.pod
new file mode 100644
index 00000000000..c02ddd3fa1e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perllinux.pod
@@ -0,0 +1,39 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.linux - Perl version 5 on Linux systems
+
+=head1 DESCRIPTION
+
+This document describes various features of Linux that will affect how Perl
+version 5 (hereafter just Perl) is compiled and/or runs.
+
+=head2 Experimental Support for Sun Studio Compilers for Linux OS
+
+Sun Microsystems has released a port of their Sun Studio compiliers for
+Linux. As of November 2005, only an alpha version has been released.
+Until a release of these compilers is made, support for compiling Perl with
+these compiler experimental.
+
+Also, some special instructions for building Perl with Sun Studio on Linux.
+Following the normal C<Configure>, you have to run make as follows:
+
+ LDLOADLIBS=-lc make
+
+C<LDLOADLIBS> is an environment variable used by the linker to link modules
+C</ext> modules to glibc. Currently, that environment variable is not getting
+populated by a combination of C<Config> entries and C<ExtUtil::MakeMaker>.
+While there may be a bug somewhere in Perl's configuration or
+C<ExtUtil::MakeMaker> causing the problem, the most likely cause is an
+incomplete understanding of Sun Studio by this author. Further investigation
+is needed to get this working better.
+
+=head1 AUTHOR
+
+Steve Peters <steve@fisharerojo.org>
+
+Please report any errors, updates, or suggestions to F<perlbug@perl.org>.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perllocale.pod b/Master/tlpkg/tlperl/lib/pods/perllocale.pod
new file mode 100644
index 00000000000..0dbabe7d401
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perllocale.pod
@@ -0,0 +1,1046 @@
+=head1 NAME
+
+perllocale - Perl locale handling (internationalization and localization)
+
+=head1 DESCRIPTION
+
+Perl supports language-specific notions of data such as "is this
+a letter", "what is the uppercase equivalent of this letter", and
+"which of these letters comes first". These are important issues,
+especially for languages other than English--but also for English: it
+would be naE<iuml>ve to imagine that C<A-Za-z> defines all the "letters"
+needed to write in English. Perl is also aware that some character other
+than '.' may be preferred as a decimal point, and that output date
+representations may be language-specific. The process of making an
+application take account of its users' preferences in such matters is
+called B<internationalization> (often abbreviated as B<i18n>); telling
+such an application about a particular set of preferences is known as
+B<localization> (B<l10n>).
+
+Perl can understand language-specific data via the standardized (ISO C,
+XPG4, POSIX 1.c) method called "the locale system". The locale system is
+controlled per application using one pragma, one function call, and
+several environment variables.
+
+B<NOTE>: This feature is new in Perl 5.004, and does not apply unless an
+application specifically requests it--see L<Backward compatibility>.
+The one exception is that write() now B<always> uses the current locale
+- see L<"NOTES">.
+
+=head1 PREPARING TO USE LOCALES
+
+If Perl applications are to understand and present your data
+correctly according a locale of your choice, B<all> of the following
+must be true:
+
+=over 4
+
+=item *
+
+B<Your operating system must support the locale system>. If it does,
+you should find that the setlocale() function is a documented part of
+its C library.
+
+=item *
+
+B<Definitions for locales that you use must be installed>. You, or
+your system administrator, must make sure that this is the case. The
+available locales, the location in which they are kept, and the manner
+in which they are installed all vary from system to system. Some systems
+provide only a few, hard-wired locales and do not allow more to be
+added. Others allow you to add "canned" locales provided by the system
+supplier. Still others allow you or the system administrator to define
+and add arbitrary locales. (You may have to ask your supplier to
+provide canned locales that are not delivered with your operating
+system.) Read your system documentation for further illumination.
+
+=item *
+
+B<Perl must believe that the locale system is supported>. If it does,
+C<perl -V:d_setlocale> will say that the value for C<d_setlocale> is
+C<define>.
+
+=back
+
+If you want a Perl application to process and present your data
+according to a particular locale, the application code should include
+the S<C<use locale>> pragma (see L<The use locale pragma>) where
+appropriate, and B<at least one> of the following must be true:
+
+=over 4
+
+=item *
+
+B<The locale-determining environment variables (see L<"ENVIRONMENT">)
+must be correctly set up> at the time the application is started, either
+by yourself or by whoever set up your system account.
+
+=item *
+
+B<The application must set its own locale> using the method described in
+L<The setlocale function>.
+
+=back
+
+=head1 USING LOCALES
+
+=head2 The use locale pragma
+
+By default, Perl ignores the current locale. The S<C<use locale>>
+pragma tells Perl to use the current locale for some operations:
+
+=over 4
+
+=item *
+
+B<The comparison operators> (C<lt>, C<le>, C<cmp>, C<ge>, and C<gt>) and
+the POSIX string collation functions strcoll() and strxfrm() use
+C<LC_COLLATE>. sort() is also affected if used without an
+explicit comparison function, because it uses C<cmp> by default.
+
+B<Note:> C<eq> and C<ne> are unaffected by locale: they always
+perform a char-by-char comparison of their scalar operands. What's
+more, if C<cmp> finds that its operands are equal according to the
+collation sequence specified by the current locale, it goes on to
+perform a char-by-char comparison, and only returns I<0> (equal) if the
+operands are char-for-char identical. If you really want to know whether
+two strings--which C<eq> and C<cmp> may consider different--are equal
+as far as collation in the locale is concerned, see the discussion in
+L<Category LC_COLLATE: Collation>.
+
+=item *
+
+B<Regular expressions and case-modification functions> (uc(), lc(),
+ucfirst(), and lcfirst()) use C<LC_CTYPE>
+
+=item *
+
+B<The formatting functions> (printf(), sprintf() and write()) use
+C<LC_NUMERIC>
+
+=item *
+
+B<The POSIX date formatting function> (strftime()) uses C<LC_TIME>.
+
+=back
+
+C<LC_COLLATE>, C<LC_CTYPE>, and so on, are discussed further in
+L<LOCALE CATEGORIES>.
+
+The default behavior is restored with the S<C<no locale>> pragma, or
+upon reaching the end of block enclosing C<use locale>.
+
+The string result of any operation that uses locale
+information is tainted, as it is possible for a locale to be
+untrustworthy. See L<"SECURITY">.
+
+=head2 The setlocale function
+
+You can switch locales as often as you wish at run time with the
+POSIX::setlocale() function:
+
+ # This functionality not usable prior to Perl 5.004
+ require 5.004;
+
+ # Import locale-handling tool set from POSIX module.
+ # This example uses: setlocale -- the function call
+ # LC_CTYPE -- explained below
+ use POSIX qw(locale_h);
+
+ # query and save the old locale
+ $old_locale = setlocale(LC_CTYPE);
+
+ setlocale(LC_CTYPE, "fr_CA.ISO8859-1");
+ # LC_CTYPE now in locale "French, Canada, codeset ISO 8859-1"
+
+ setlocale(LC_CTYPE, "");
+ # LC_CTYPE now reset to default defined by LC_ALL/LC_CTYPE/LANG
+ # environment variables. See below for documentation.
+
+ # restore the old locale
+ setlocale(LC_CTYPE, $old_locale);
+
+The first argument of setlocale() gives the B<category>, the second the
+B<locale>. The category tells in what aspect of data processing you
+want to apply locale-specific rules. Category names are discussed in
+L<LOCALE CATEGORIES> and L<"ENVIRONMENT">. The locale is the name of a
+collection of customization information corresponding to a particular
+combination of language, country or territory, and codeset. Read on for
+hints on the naming of locales: not all systems name locales as in the
+example.
+
+If no second argument is provided and the category is something else
+than LC_ALL, the function returns a string naming the current locale
+for the category. You can use this value as the second argument in a
+subsequent call to setlocale().
+
+If no second argument is provided and the category is LC_ALL, the
+result is implementation-dependent. It may be a string of
+concatenated locales names (separator also implementation-dependent)
+or a single locale name. Please consult your setlocale(3) man page for
+details.
+
+If a second argument is given and it corresponds to a valid locale,
+the locale for the category is set to that value, and the function
+returns the now-current locale value. You can then use this in yet
+another call to setlocale(). (In some implementations, the return
+value may sometimes differ from the value you gave as the second
+argument--think of it as an alias for the value you gave.)
+
+As the example shows, if the second argument is an empty string, the
+category's locale is returned to the default specified by the
+corresponding environment variables. Generally, this results in a
+return to the default that was in force when Perl started up: changes
+to the environment made by the application after startup may or may not
+be noticed, depending on your system's C library.
+
+If the second argument does not correspond to a valid locale, the locale
+for the category is not changed, and the function returns I<undef>.
+
+For further information about the categories, consult setlocale(3).
+
+=head2 Finding locales
+
+For locales available in your system, consult also setlocale(3) to
+see whether it leads to the list of available locales (search for the
+I<SEE ALSO> section). If that fails, try the following command lines:
+
+ locale -a
+
+ nlsinfo
+
+ ls /usr/lib/nls/loc
+
+ ls /usr/lib/locale
+
+ ls /usr/lib/nls
+
+ ls /usr/share/locale
+
+and see whether they list something resembling these
+
+ en_US.ISO8859-1 de_DE.ISO8859-1 ru_RU.ISO8859-5
+ en_US.iso88591 de_DE.iso88591 ru_RU.iso88595
+ en_US de_DE ru_RU
+ en de ru
+ english german russian
+ english.iso88591 german.iso88591 russian.iso88595
+ english.roman8 russian.koi8r
+
+Sadly, even though the calling interface for setlocale() has been
+standardized, names of locales and the directories where the
+configuration resides have not been. The basic form of the name is
+I<language_territory>B<.>I<codeset>, but the latter parts after
+I<language> are not always present. The I<language> and I<country>
+are usually from the standards B<ISO 3166> and B<ISO 639>, the
+two-letter abbreviations for the countries and the languages of the
+world, respectively. The I<codeset> part often mentions some B<ISO
+8859> character set, the Latin codesets. For example, C<ISO 8859-1>
+is the so-called "Western European codeset" that can be used to encode
+most Western European languages adequately. Again, there are several
+ways to write even the name of that one standard. Lamentably.
+
+Two special locales are worth particular mention: "C" and "POSIX".
+Currently these are effectively the same locale: the difference is
+mainly that the first one is defined by the C standard, the second by
+the POSIX standard. They define the B<default locale> in which
+every program starts in the absence of locale information in its
+environment. (The I<default> default locale, if you will.) Its language
+is (American) English and its character codeset ASCII.
+
+B<NOTE>: Not all systems have the "POSIX" locale (not all systems are
+POSIX-conformant), so use "C" when you need explicitly to specify this
+default locale.
+
+=head2 LOCALE PROBLEMS
+
+You may encounter the following warning message at Perl startup:
+
+ perl: warning: Setting locale failed.
+ perl: warning: Please check that your locale settings:
+ LC_ALL = "En_US",
+ LANG = (unset)
+ are supported and installed on your system.
+ perl: warning: Falling back to the standard locale ("C").
+
+This means that your locale settings had LC_ALL set to "En_US" and
+LANG exists but has no value. Perl tried to believe you but could not.
+Instead, Perl gave up and fell back to the "C" locale, the default locale
+that is supposed to work no matter what. This usually means your locale
+settings were wrong, they mention locales your system has never heard
+of, or the locale installation in your system has problems (for example,
+some system files are broken or missing). There are quick and temporary
+fixes to these problems, as well as more thorough and lasting fixes.
+
+=head2 Temporarily fixing locale problems
+
+The two quickest fixes are either to render Perl silent about any
+locale inconsistencies or to run Perl under the default locale "C".
+
+Perl's moaning about locale problems can be silenced by setting the
+environment variable PERL_BADLANG to a zero value, for example "0".
+This method really just sweeps the problem under the carpet: you tell
+Perl to shut up even when Perl sees that something is wrong. Do not
+be surprised if later something locale-dependent misbehaves.
+
+Perl can be run under the "C" locale by setting the environment
+variable LC_ALL to "C". This method is perhaps a bit more civilized
+than the PERL_BADLANG approach, but setting LC_ALL (or
+other locale variables) may affect other programs as well, not just
+Perl. In particular, external programs run from within Perl will see
+these changes. If you make the new settings permanent (read on), all
+programs you run see the changes. See L<"ENVIRONMENT"> for
+the full list of relevant environment variables and L<USING LOCALES>
+for their effects in Perl. Effects in other programs are
+easily deducible. For example, the variable LC_COLLATE may well affect
+your B<sort> program (or whatever the program that arranges "records"
+alphabetically in your system is called).
+
+You can test out changing these variables temporarily, and if the
+new settings seem to help, put those settings into your shell startup
+files. Consult your local documentation for the exact details. For in
+Bourne-like shells (B<sh>, B<ksh>, B<bash>, B<zsh>):
+
+ LC_ALL=en_US.ISO8859-1
+ export LC_ALL
+
+This assumes that we saw the locale "en_US.ISO8859-1" using the commands
+discussed above. We decided to try that instead of the above faulty
+locale "En_US"--and in Cshish shells (B<csh>, B<tcsh>)
+
+ setenv LC_ALL en_US.ISO8859-1
+
+or if you have the "env" application you can do in any shell
+
+ env LC_ALL=en_US.ISO8859-1 perl ...
+
+If you do not know what shell you have, consult your local
+helpdesk or the equivalent.
+
+=head2 Permanently fixing locale problems
+
+The slower but superior fixes are when you may be able to yourself
+fix the misconfiguration of your own environment variables. The
+mis(sing)configuration of the whole system's locales usually requires
+the help of your friendly system administrator.
+
+First, see earlier in this document about L<Finding locales>. That tells
+how to find which locales are really supported--and more importantly,
+installed--on your system. In our example error message, environment
+variables affecting the locale are listed in the order of decreasing
+importance (and unset variables do not matter). Therefore, having
+LC_ALL set to "En_US" must have been the bad choice, as shown by the
+error message. First try fixing locale settings listed first.
+
+Second, if using the listed commands you see something B<exactly>
+(prefix matches do not count and case usually counts) like "En_US"
+without the quotes, then you should be okay because you are using a
+locale name that should be installed and available in your system.
+In this case, see L<Permanently fixing your system's locale configuration>.
+
+=head2 Permanently fixing your system's locale configuration
+
+This is when you see something like:
+
+ perl: warning: Please check that your locale settings:
+ LC_ALL = "En_US",
+ LANG = (unset)
+ are supported and installed on your system.
+
+but then cannot see that "En_US" listed by the above-mentioned
+commands. You may see things like "en_US.ISO8859-1", but that isn't
+the same. In this case, try running under a locale
+that you can list and which somehow matches what you tried. The
+rules for matching locale names are a bit vague because
+standardization is weak in this area. See again the
+L<Finding locales> about general rules.
+
+=head2 Fixing system locale configuration
+
+Contact a system administrator (preferably your own) and report the exact
+error message you get, and ask them to read this same documentation you
+are now reading. They should be able to check whether there is something
+wrong with the locale configuration of the system. The L<Finding locales>
+section is unfortunately a bit vague about the exact commands and places
+because these things are not that standardized.
+
+=head2 The localeconv function
+
+The POSIX::localeconv() function allows you to get particulars of the
+locale-dependent numeric formatting information specified by the current
+C<LC_NUMERIC> and C<LC_MONETARY> locales. (If you just want the name of
+the current locale for a particular category, use POSIX::setlocale()
+with a single parameter--see L<The setlocale function>.)
+
+ use POSIX qw(locale_h);
+
+ # Get a reference to a hash of locale-dependent info
+ $locale_values = localeconv();
+
+ # Output sorted list of the values
+ for (sort keys %$locale_values) {
+ printf "%-20s = %s\n", $_, $locale_values->{$_}
+ }
+
+localeconv() takes no arguments, and returns B<a reference to> a hash.
+The keys of this hash are variable names for formatting, such as
+C<decimal_point> and C<thousands_sep>. The values are the
+corresponding, er, values. See L<POSIX/localeconv> for a longer
+example listing the categories an implementation might be expected to
+provide; some provide more and others fewer. You don't need an
+explicit C<use locale>, because localeconv() always observes the
+current locale.
+
+Here's a simple-minded example program that rewrites its command-line
+parameters as integers correctly formatted in the current locale:
+
+ # See comments in previous example
+ require 5.004;
+ use POSIX qw(locale_h);
+
+ # Get some of locale's numeric formatting parameters
+ my ($thousands_sep, $grouping) =
+ @{localeconv()}{'thousands_sep', 'grouping'};
+
+ # Apply defaults if values are missing
+ $thousands_sep = ',' unless $thousands_sep;
+
+ # grouping and mon_grouping are packed lists
+ # of small integers (characters) telling the
+ # grouping (thousand_seps and mon_thousand_seps
+ # being the group dividers) of numbers and
+ # monetary quantities. The integers' meanings:
+ # 255 means no more grouping, 0 means repeat
+ # the previous grouping, 1-254 means use that
+ # as the current grouping. Grouping goes from
+ # right to left (low to high digits). In the
+ # below we cheat slightly by never using anything
+ # else than the first grouping (whatever that is).
+ if ($grouping) {
+ @grouping = unpack("C*", $grouping);
+ } else {
+ @grouping = (3);
+ }
+
+ # Format command line params for current locale
+ for (@ARGV) {
+ $_ = int; # Chop non-integer part
+ 1 while
+ s/(\d)(\d{$grouping[0]}($|$thousands_sep))/$1$thousands_sep$2/;
+ print "$_";
+ }
+ print "\n";
+
+=head2 I18N::Langinfo
+
+Another interface for querying locale-dependent information is the
+I18N::Langinfo::langinfo() function, available at least in Unix-like
+systems and VMS.
+
+The following example will import the langinfo() function itself and
+three constants to be used as arguments to langinfo(): a constant for
+the abbreviated first day of the week (the numbering starts from
+Sunday = 1) and two more constants for the affirmative and negative
+answers for a yes/no question in the current locale.
+
+ use I18N::Langinfo qw(langinfo ABDAY_1 YESSTR NOSTR);
+
+ my ($abday_1, $yesstr, $nostr) = map { langinfo } qw(ABDAY_1 YESSTR NOSTR);
+
+ print "$abday_1? [$yesstr/$nostr] ";
+
+In other words, in the "C" (or English) locale the above will probably
+print something like:
+
+ Sun? [yes/no]
+
+See L<I18N::Langinfo> for more information.
+
+=head1 LOCALE CATEGORIES
+
+The following subsections describe basic locale categories. Beyond these,
+some combination categories allow manipulation of more than one
+basic category at a time. See L<"ENVIRONMENT"> for a discussion of these.
+
+=head2 Category LC_COLLATE: Collation
+
+In the scope of S<C<use locale>>, Perl looks to the C<LC_COLLATE>
+environment variable to determine the application's notions on collation
+(ordering) of characters. For example, 'b' follows 'a' in Latin
+alphabets, but where do 'E<aacute>' and 'E<aring>' belong? And while
+'color' follows 'chocolate' in English, what about in Spanish?
+
+The following collations all make sense and you may meet any of them
+if you "use locale".
+
+ A B C D E a b c d e
+ A a B b C c D d E e
+ a A b B c C d D e E
+ a b c d e A B C D E
+
+Here is a code snippet to tell what "word"
+characters are in the current locale, in that locale's order:
+
+ use locale;
+ print +(sort grep /\w/, map { chr } 0..255), "\n";
+
+Compare this with the characters that you see and their order if you
+state explicitly that the locale should be ignored:
+
+ no locale;
+ print +(sort grep /\w/, map { chr } 0..255), "\n";
+
+This machine-native collation (which is what you get unless S<C<use
+locale>> has appeared earlier in the same block) must be used for
+sorting raw binary data, whereas the locale-dependent collation of the
+first example is useful for natural text.
+
+As noted in L<USING LOCALES>, C<cmp> compares according to the current
+collation locale when C<use locale> is in effect, but falls back to a
+char-by-char comparison for strings that the locale says are equal. You
+can use POSIX::strcoll() if you don't want this fall-back:
+
+ use POSIX qw(strcoll);
+ $equal_in_locale =
+ !strcoll("space and case ignored", "SpaceAndCaseIgnored");
+
+$equal_in_locale will be true if the collation locale specifies a
+dictionary-like ordering that ignores space characters completely and
+which folds case.
+
+If you have a single string that you want to check for "equality in
+locale" against several others, you might think you could gain a little
+efficiency by using POSIX::strxfrm() in conjunction with C<eq>:
+
+ use POSIX qw(strxfrm);
+ $xfrm_string = strxfrm("Mixed-case string");
+ print "locale collation ignores spaces\n"
+ if $xfrm_string eq strxfrm("Mixed-casestring");
+ print "locale collation ignores hyphens\n"
+ if $xfrm_string eq strxfrm("Mixedcase string");
+ print "locale collation ignores case\n"
+ if $xfrm_string eq strxfrm("mixed-case string");
+
+strxfrm() takes a string and maps it into a transformed string for use
+in char-by-char comparisons against other transformed strings during
+collation. "Under the hood", locale-affected Perl comparison operators
+call strxfrm() for both operands, then do a char-by-char
+comparison of the transformed strings. By calling strxfrm() explicitly
+and using a non locale-affected comparison, the example attempts to save
+a couple of transformations. But in fact, it doesn't save anything: Perl
+magic (see L<perlguts/Magic Variables>) creates the transformed version of a
+string the first time it's needed in a comparison, then keeps this version around
+in case it's needed again. An example rewritten the easy way with
+C<cmp> runs just about as fast. It also copes with null characters
+embedded in strings; if you call strxfrm() directly, it treats the first
+null it finds as a terminator. don't expect the transformed strings
+it produces to be portable across systems--or even from one revision
+of your operating system to the next. In short, don't call strxfrm()
+directly: let Perl do it for you.
+
+Note: C<use locale> isn't shown in some of these examples because it isn't
+needed: strcoll() and strxfrm() exist only to generate locale-dependent
+results, and so always obey the current C<LC_COLLATE> locale.
+
+=head2 Category LC_CTYPE: Character Types
+
+In the scope of S<C<use locale>>, Perl obeys the C<LC_CTYPE> locale
+setting. This controls the application's notion of which characters are
+alphabetic. This affects Perl's C<\w> regular expression metanotation,
+which stands for alphanumeric characters--that is, alphabetic,
+numeric, and including other special characters such as the underscore or
+hyphen. (Consult L<perlre> for more information about
+regular expressions.) Thanks to C<LC_CTYPE>, depending on your locale
+setting, characters like 'E<aelig>', 'E<eth>', 'E<szlig>', and
+'E<oslash>' may be understood as C<\w> characters.
+
+The C<LC_CTYPE> locale also provides the map used in transliterating
+characters between lower and uppercase. This affects the case-mapping
+functions--lc(), lcfirst, uc(), and ucfirst(); case-mapping
+interpolation with C<\l>, C<\L>, C<\u>, or C<\U> in double-quoted strings
+and C<s///> substitutions; and case-independent regular expression
+pattern matching using the C<i> modifier.
+
+Finally, C<LC_CTYPE> affects the POSIX character-class test
+functions--isalpha(), islower(), and so on. For example, if you move
+from the "C" locale to a 7-bit Scandinavian one, you may find--possibly
+to your surprise--that "|" moves from the ispunct() class to isalpha().
+
+B<Note:> A broken or malicious C<LC_CTYPE> locale definition may result
+in clearly ineligible characters being considered to be alphanumeric by
+your application. For strict matching of (mundane) letters and
+digits--for example, in command strings--locale-aware applications
+should use C<\w> inside a C<no locale> block. See L<"SECURITY">.
+
+=head2 Category LC_NUMERIC: Numeric Formatting
+
+After a proper POSIX::setlocale() call, Perl obeys the C<LC_NUMERIC>
+locale information, which controls an application's idea of how numbers
+should be formatted for human readability by the printf(), sprintf(), and
+write() functions. String-to-numeric conversion by the POSIX::strtod()
+function is also affected. In most implementations the only effect is to
+change the character used for the decimal point--perhaps from '.' to ','.
+These functions aren't aware of such niceties as thousands separation and
+so on. (See L<The localeconv function> if you care about these things.)
+
+Output produced by print() is also affected by the current locale: it
+corresponds to what you'd get from printf() in the "C" locale. The
+same is true for Perl's internal conversions between numeric and
+string formats:
+
+ use POSIX qw(strtod setlocale LC_NUMERIC);
+
+ setlocale LC_NUMERIC, "";
+
+ $n = 5/2; # Assign numeric 2.5 to $n
+
+ $a = " $n"; # Locale-dependent conversion to string
+
+ print "half five is $n\n"; # Locale-dependent output
+
+ printf "half five is %g\n", $n; # Locale-dependent output
+
+ print "DECIMAL POINT IS COMMA\n"
+ if $n == (strtod("2,5"))[0]; # Locale-dependent conversion
+
+See also L<I18N::Langinfo> and C<RADIXCHAR>.
+
+=head2 Category LC_MONETARY: Formatting of monetary amounts
+
+The C standard defines the C<LC_MONETARY> category, but no function
+that is affected by its contents. (Those with experience of standards
+committees will recognize that the working group decided to punt on the
+issue.) Consequently, Perl takes no notice of it. If you really want
+to use C<LC_MONETARY>, you can query its contents--see
+L<The localeconv function>--and use the information that it returns in your
+application's own formatting of currency amounts. However, you may well
+find that the information, voluminous and complex though it may be, still
+does not quite meet your requirements: currency formatting is a hard nut
+to crack.
+
+See also L<I18N::Langinfo> and C<CRNCYSTR>.
+
+=head2 LC_TIME
+
+Output produced by POSIX::strftime(), which builds a formatted
+human-readable date/time string, is affected by the current C<LC_TIME>
+locale. Thus, in a French locale, the output produced by the C<%B>
+format element (full month name) for the first month of the year would
+be "janvier". Here's how to get a list of long month names in the
+current locale:
+
+ use POSIX qw(strftime);
+ for (0..11) {
+ $long_month_name[$_] =
+ strftime("%B", 0, 0, 0, 1, $_, 96);
+ }
+
+Note: C<use locale> isn't needed in this example: as a function that
+exists only to generate locale-dependent results, strftime() always
+obeys the current C<LC_TIME> locale.
+
+See also L<I18N::Langinfo> and C<ABDAY_1>..C<ABDAY_7>, C<DAY_1>..C<DAY_7>,
+C<ABMON_1>..C<ABMON_12>, and C<ABMON_1>..C<ABMON_12>.
+
+=head2 Other categories
+
+The remaining locale category, C<LC_MESSAGES> (possibly supplemented
+by others in particular implementations) is not currently used by
+Perl--except possibly to affect the behavior of library functions
+called by extensions outside the standard Perl distribution and by the
+operating system and its utilities. Note especially that the string
+value of C<$!> and the error messages given by external utilities may
+be changed by C<LC_MESSAGES>. If you want to have portable error
+codes, use C<%!>. See L<Errno>.
+
+=head1 SECURITY
+
+Although the main discussion of Perl security issues can be found in
+L<perlsec>, a discussion of Perl's locale handling would be incomplete
+if it did not draw your attention to locale-dependent security issues.
+Locales--particularly on systems that allow unprivileged users to
+build their own locales--are untrustworthy. A malicious (or just plain
+broken) locale can make a locale-aware application give unexpected
+results. Here are a few possibilities:
+
+=over 4
+
+=item *
+
+Regular expression checks for safe file names or mail addresses using
+C<\w> may be spoofed by an C<LC_CTYPE> locale that claims that
+characters such as "E<gt>" and "|" are alphanumeric.
+
+=item *
+
+String interpolation with case-mapping, as in, say, C<$dest =
+"C:\U$name.$ext">, may produce dangerous results if a bogus LC_CTYPE
+case-mapping table is in effect.
+
+=item *
+
+A sneaky C<LC_COLLATE> locale could result in the names of students with
+"D" grades appearing ahead of those with "A"s.
+
+=item *
+
+An application that takes the trouble to use information in
+C<LC_MONETARY> may format debits as if they were credits and vice versa
+if that locale has been subverted. Or it might make payments in US
+dollars instead of Hong Kong dollars.
+
+=item *
+
+The date and day names in dates formatted by strftime() could be
+manipulated to advantage by a malicious user able to subvert the
+C<LC_DATE> locale. ("Look--it says I wasn't in the building on
+Sunday.")
+
+=back
+
+Such dangers are not peculiar to the locale system: any aspect of an
+application's environment which may be modified maliciously presents
+similar challenges. Similarly, they are not specific to Perl: any
+programming language that allows you to write programs that take
+account of their environment exposes you to these issues.
+
+Perl cannot protect you from all possibilities shown in the
+examples--there is no substitute for your own vigilance--but, when
+C<use locale> is in effect, Perl uses the tainting mechanism (see
+L<perlsec>) to mark string results that become locale-dependent, and
+which may be untrustworthy in consequence. Here is a summary of the
+tainting behavior of operators and functions that may be affected by
+the locale:
+
+=over 4
+
+=item *
+
+B<Comparison operators> (C<lt>, C<le>, C<ge>, C<gt> and C<cmp>):
+
+Scalar true/false (or less/equal/greater) result is never tainted.
+
+=item *
+
+B<Case-mapping interpolation> (with C<\l>, C<\L>, C<\u> or C<\U>)
+
+Result string containing interpolated material is tainted if
+C<use locale> is in effect.
+
+=item *
+
+B<Matching operator> (C<m//>):
+
+Scalar true/false result never tainted.
+
+Subpatterns, either delivered as a list-context result or as $1 etc.
+are tainted if C<use locale> is in effect, and the subpattern regular
+expression contains C<\w> (to match an alphanumeric character), C<\W>
+(non-alphanumeric character), C<\s> (whitespace character), or C<\S>
+(non whitespace character). The matched-pattern variable, $&, $`
+(pre-match), $' (post-match), and $+ (last match) are also tainted if
+C<use locale> is in effect and the regular expression contains C<\w>,
+C<\W>, C<\s>, or C<\S>.
+
+=item *
+
+B<Substitution operator> (C<s///>):
+
+Has the same behavior as the match operator. Also, the left
+operand of C<=~> becomes tainted when C<use locale> in effect
+if modified as a result of a substitution based on a regular
+expression match involving C<\w>, C<\W>, C<\s>, or C<\S>; or of
+case-mapping with C<\l>, C<\L>,C<\u> or C<\U>.
+
+=item *
+
+B<Output formatting functions> (printf() and write()):
+
+Results are never tainted because otherwise even output from print,
+for example C<print(1/7)>, should be tainted if C<use locale> is in
+effect.
+
+=item *
+
+B<Case-mapping functions> (lc(), lcfirst(), uc(), ucfirst()):
+
+Results are tainted if C<use locale> is in effect.
+
+=item *
+
+B<POSIX locale-dependent functions> (localeconv(), strcoll(),
+strftime(), strxfrm()):
+
+Results are never tainted.
+
+=item *
+
+B<POSIX character class tests> (isalnum(), isalpha(), isdigit(),
+isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(),
+isxdigit()):
+
+True/false results are never tainted.
+
+=back
+
+Three examples illustrate locale-dependent tainting.
+The first program, which ignores its locale, won't run: a value taken
+directly from the command line may not be used to name an output file
+when taint checks are enabled.
+
+ #/usr/local/bin/perl -T
+ # Run with taint checking
+
+ # Command line sanity check omitted...
+ $tainted_output_file = shift;
+
+ open(F, ">$tainted_output_file")
+ or warn "Open of $untainted_output_file failed: $!\n";
+
+The program can be made to run by "laundering" the tainted value through
+a regular expression: the second example--which still ignores locale
+information--runs, creating the file named on its command line
+if it can.
+
+ #/usr/local/bin/perl -T
+
+ $tainted_output_file = shift;
+ $tainted_output_file =~ m%[\w/]+%;
+ $untainted_output_file = $&;
+
+ open(F, ">$untainted_output_file")
+ or warn "Open of $untainted_output_file failed: $!\n";
+
+Compare this with a similar but locale-aware program:
+
+ #/usr/local/bin/perl -T
+
+ $tainted_output_file = shift;
+ use locale;
+ $tainted_output_file =~ m%[\w/]+%;
+ $localized_output_file = $&;
+
+ open(F, ">$localized_output_file")
+ or warn "Open of $localized_output_file failed: $!\n";
+
+This third program fails to run because $& is tainted: it is the result
+of a match involving C<\w> while C<use locale> is in effect.
+
+=head1 ENVIRONMENT
+
+=over 12
+
+=item PERL_BADLANG
+
+A string that can suppress Perl's warning about failed locale settings
+at startup. Failure can occur if the locale support in the operating
+system is lacking (broken) in some way--or if you mistyped the name of
+a locale when you set up your environment. If this environment
+variable is absent, or has a value that does not evaluate to integer
+zero--that is, "0" or ""-- Perl will complain about locale setting
+failures.
+
+B<NOTE>: PERL_BADLANG only gives you a way to hide the warning message.
+The message tells about some problem in your system's locale support,
+and you should investigate what the problem is.
+
+=back
+
+The following environment variables are not specific to Perl: They are
+part of the standardized (ISO C, XPG4, POSIX 1.c) setlocale() method
+for controlling an application's opinion on data.
+
+=over 12
+
+=item LC_ALL
+
+C<LC_ALL> is the "override-all" locale environment variable. If
+set, it overrides all the rest of the locale environment variables.
+
+=item LANGUAGE
+
+B<NOTE>: C<LANGUAGE> is a GNU extension, it affects you only if you
+are using the GNU libc. This is the case if you are using e.g. Linux.
+If you are using "commercial" Unixes you are most probably I<not>
+using GNU libc and you can ignore C<LANGUAGE>.
+
+However, in the case you are using C<LANGUAGE>: it affects the
+language of informational, warning, and error messages output by
+commands (in other words, it's like C<LC_MESSAGES>) but it has higher
+priority than L<LC_ALL>. Moreover, it's not a single value but
+instead a "path" (":"-separated list) of I<languages> (not locales).
+See the GNU C<gettext> library documentation for more information.
+
+=item LC_CTYPE
+
+In the absence of C<LC_ALL>, C<LC_CTYPE> chooses the character type
+locale. In the absence of both C<LC_ALL> and C<LC_CTYPE>, C<LANG>
+chooses the character type locale.
+
+=item LC_COLLATE
+
+In the absence of C<LC_ALL>, C<LC_COLLATE> chooses the collation
+(sorting) locale. In the absence of both C<LC_ALL> and C<LC_COLLATE>,
+C<LANG> chooses the collation locale.
+
+=item LC_MONETARY
+
+In the absence of C<LC_ALL>, C<LC_MONETARY> chooses the monetary
+formatting locale. In the absence of both C<LC_ALL> and C<LC_MONETARY>,
+C<LANG> chooses the monetary formatting locale.
+
+=item LC_NUMERIC
+
+In the absence of C<LC_ALL>, C<LC_NUMERIC> chooses the numeric format
+locale. In the absence of both C<LC_ALL> and C<LC_NUMERIC>, C<LANG>
+chooses the numeric format.
+
+=item LC_TIME
+
+In the absence of C<LC_ALL>, C<LC_TIME> chooses the date and time
+formatting locale. In the absence of both C<LC_ALL> and C<LC_TIME>,
+C<LANG> chooses the date and time formatting locale.
+
+=item LANG
+
+C<LANG> is the "catch-all" locale environment variable. If it is set, it
+is used as the last resort after the overall C<LC_ALL> and the
+category-specific C<LC_...>.
+
+=back
+
+=head2 Examples
+
+The LC_NUMERIC controls the numeric output:
+
+ use locale;
+ use POSIX qw(locale_h); # Imports setlocale() and the LC_ constants.
+ setlocale(LC_NUMERIC, "fr_FR") or die "Pardon";
+ printf "%g\n", 1.23; # If the "fr_FR" succeeded, probably shows 1,23.
+
+and also how strings are parsed by POSIX::strtod() as numbers:
+
+ use locale;
+ use POSIX qw(locale_h strtod);
+ setlocale(LC_NUMERIC, "de_DE") or die "Entschuldigung";
+ my $x = strtod("2,34") + 5;
+ print $x, "\n"; # Probably shows 7,34.
+
+=head1 NOTES
+
+=head2 Backward compatibility
+
+Versions of Perl prior to 5.004 B<mostly> ignored locale information,
+generally behaving as if something similar to the C<"C"> locale were
+always in force, even if the program environment suggested otherwise
+(see L<The setlocale function>). By default, Perl still behaves this
+way for backward compatibility. If you want a Perl application to pay
+attention to locale information, you B<must> use the S<C<use locale>>
+pragma (see L<The use locale pragma>) to instruct it to do so.
+
+Versions of Perl from 5.002 to 5.003 did use the C<LC_CTYPE>
+information if available; that is, C<\w> did understand what
+were the letters according to the locale environment variables.
+The problem was that the user had no control over the feature:
+if the C library supported locales, Perl used them.
+
+=head2 I18N:Collate obsolete
+
+In versions of Perl prior to 5.004, per-locale collation was possible
+using the C<I18N::Collate> library module. This module is now mildly
+obsolete and should be avoided in new applications. The C<LC_COLLATE>
+functionality is now integrated into the Perl core language: One can
+use locale-specific scalar data completely normally with C<use locale>,
+so there is no longer any need to juggle with the scalar references of
+C<I18N::Collate>.
+
+=head2 Sort speed and memory use impacts
+
+Comparing and sorting by locale is usually slower than the default
+sorting; slow-downs of two to four times have been observed. It will
+also consume more memory: once a Perl scalar variable has participated
+in any string comparison or sorting operation obeying the locale
+collation rules, it will take 3-15 times more memory than before. (The
+exact multiplier depends on the string's contents, the operating system
+and the locale.) These downsides are dictated more by the operating
+system's implementation of the locale system than by Perl.
+
+=head2 write() and LC_NUMERIC
+
+Formats are the only part of Perl that unconditionally use information
+from a program's locale; if a program's environment specifies an
+LC_NUMERIC locale, it is always used to specify the decimal point
+character in formatted output. Formatted output cannot be controlled by
+C<use locale> because the pragma is tied to the block structure of the
+program, and, for historical reasons, formats exist outside that block
+structure.
+
+=head2 Freely available locale definitions
+
+There is a large collection of locale definitions at:
+
+ http://std.dkuug.dk/i18n/WG15-collection/locales/
+
+You should be aware that it is
+unsupported, and is not claimed to be fit for any purpose. If your
+system allows installation of arbitrary locales, you may find the
+definitions useful as they are, or as a basis for the development of
+your own locales.
+
+=head2 I18n and l10n
+
+"Internationalization" is often abbreviated as B<i18n> because its first
+and last letters are separated by eighteen others. (You may guess why
+the internalin ... internaliti ... i18n tends to get abbreviated.) In
+the same way, "localization" is often abbreviated to B<l10n>.
+
+=head2 An imperfect standard
+
+Internationalization, as defined in the C and POSIX standards, can be
+criticized as incomplete, ungainly, and having too large a granularity.
+(Locales apply to a whole process, when it would arguably be more useful
+to have them apply to a single thread, window group, or whatever.) They
+also have a tendency, like standards groups, to divide the world into
+nations, when we all know that the world can equally well be divided
+into bankers, bikers, gamers, and so on. But, for now, it's the only
+standard we've got. This may be construed as a bug.
+
+=head1 Unicode and UTF-8
+
+The support of Unicode is new starting from Perl version 5.6, and
+more fully implemented in the version 5.8. See L<perluniintro> and
+L<perlunicode> for more details.
+
+Usually locale settings and Unicode do not affect each other, but
+there are exceptions, see L<perlunicode/Locales> for examples.
+
+=head1 BUGS
+
+=head2 Broken systems
+
+In certain systems, the operating system's locale support
+is broken and cannot be fixed or used by Perl. Such deficiencies can
+and will result in mysterious hangs and/or Perl core dumps when the
+C<use locale> is in effect. When confronted with such a system,
+please report in excruciating detail to <F<perlbug@perl.org>>, and
+complain to your vendor: bug fixes may exist for these problems
+in your operating system. Sometimes such bug fixes are called an
+operating system upgrade.
+
+=head1 SEE ALSO
+
+L<I18N::Langinfo>, L<perluniintro>, L<perlunicode>, L<open>,
+L<POSIX/isalnum>, L<POSIX/isalpha>,
+L<POSIX/isdigit>, L<POSIX/isgraph>, L<POSIX/islower>,
+L<POSIX/isprint>, L<POSIX/ispunct>, L<POSIX/isspace>,
+L<POSIX/isupper>, L<POSIX/isxdigit>, L<POSIX/localeconv>,
+L<POSIX/setlocale>, L<POSIX/strcoll>, L<POSIX/strftime>,
+L<POSIX/strtod>, L<POSIX/strxfrm>.
+
+=head1 HISTORY
+
+Jarkko Hietaniemi's original F<perli18n.pod> heavily hacked by Dominic
+Dunlop, assisted by the perl5-porters. Prose worked over a bit by
+Tom Christiansen.
+
+Last update: Thu Jun 11 08:44:13 MDT 1998
diff --git a/Master/tlpkg/tlperl/lib/pods/perllol.pod b/Master/tlpkg/tlperl/lib/pods/perllol.pod
new file mode 100644
index 00000000000..58d532b12fc
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perllol.pod
@@ -0,0 +1,303 @@
+=head1 NAME
+
+perllol - Manipulating Arrays of Arrays in Perl
+
+=head1 DESCRIPTION
+
+=head2 Declaration and Access of Arrays of Arrays
+
+The simplest thing to build is an array of arrays (sometimes imprecisely
+called a list of lists). It's reasonably easy to understand, and
+almost everything that applies here will also be applicable later
+on with the fancier data structures.
+
+An array of an array is just a regular old array @AoA that you can
+get at with two subscripts, like C<$AoA[3][2]>. Here's a declaration
+of the array:
+
+ # assign to our array, an array of array references
+ @AoA = (
+ [ "fred", "barney" ],
+ [ "george", "jane", "elroy" ],
+ [ "homer", "marge", "bart" ],
+ );
+
+ print $AoA[2][2];
+ bart
+
+Now you should be very careful that the outer bracket type
+is a round one, that is, a parenthesis. That's because you're assigning to
+an @array, so you need parentheses. If you wanted there I<not> to be an @AoA,
+but rather just a reference to it, you could do something more like this:
+
+ # assign a reference to array of array references
+ $ref_to_AoA = [
+ [ "fred", "barney", "pebbles", "bambam", "dino", ],
+ [ "homer", "bart", "marge", "maggie", ],
+ [ "george", "jane", "elroy", "judy", ],
+ ];
+
+ print $ref_to_AoA->[2][2];
+
+Notice that the outer bracket type has changed, and so our access syntax
+has also changed. That's because unlike C, in perl you can't freely
+interchange arrays and references thereto. $ref_to_AoA is a reference to an
+array, whereas @AoA is an array proper. Likewise, C<$AoA[2]> is not an
+array, but an array ref. So how come you can write these:
+
+ $AoA[2][2]
+ $ref_to_AoA->[2][2]
+
+instead of having to write these:
+
+ $AoA[2]->[2]
+ $ref_to_AoA->[2]->[2]
+
+Well, that's because the rule is that on adjacent brackets only (whether
+square or curly), you are free to omit the pointer dereferencing arrow.
+But you cannot do so for the very first one if it's a scalar containing
+a reference, which means that $ref_to_AoA always needs it.
+
+=head2 Growing Your Own
+
+That's all well and good for declaration of a fixed data structure,
+but what if you wanted to add new elements on the fly, or build
+it up entirely from scratch?
+
+First, let's look at reading it in from a file. This is something like
+adding a row at a time. We'll assume that there's a flat file in which
+each line is a row and each word an element. If you're trying to develop an
+@AoA array containing all these, here's the right way to do that:
+
+ while (<>) {
+ @tmp = split;
+ push @AoA, [ @tmp ];
+ }
+
+You might also have loaded that from a function:
+
+ for $i ( 1 .. 10 ) {
+ $AoA[$i] = [ somefunc($i) ];
+ }
+
+Or you might have had a temporary variable sitting around with the
+array in it.
+
+ for $i ( 1 .. 10 ) {
+ @tmp = somefunc($i);
+ $AoA[$i] = [ @tmp ];
+ }
+
+It's very important that you make sure to use the C<[]> array reference
+constructor. That's because this will be very wrong:
+
+ $AoA[$i] = @tmp;
+
+You see, assigning a named array like that to a scalar just counts the
+number of elements in @tmp, which probably isn't what you want.
+
+If you are running under C<use strict>, you'll have to add some
+declarations to make it happy:
+
+ use strict;
+ my(@AoA, @tmp);
+ while (<>) {
+ @tmp = split;
+ push @AoA, [ @tmp ];
+ }
+
+Of course, you don't need the temporary array to have a name at all:
+
+ while (<>) {
+ push @AoA, [ split ];
+ }
+
+You also don't have to use push(). You could just make a direct assignment
+if you knew where you wanted to put it:
+
+ my (@AoA, $i, $line);
+ for $i ( 0 .. 10 ) {
+ $line = <>;
+ $AoA[$i] = [ split ' ', $line ];
+ }
+
+or even just
+
+ my (@AoA, $i);
+ for $i ( 0 .. 10 ) {
+ $AoA[$i] = [ split ' ', <> ];
+ }
+
+You should in general be leery of using functions that could
+potentially return lists in scalar context without explicitly stating
+such. This would be clearer to the casual reader:
+
+ my (@AoA, $i);
+ for $i ( 0 .. 10 ) {
+ $AoA[$i] = [ split ' ', scalar(<>) ];
+ }
+
+If you wanted to have a $ref_to_AoA variable as a reference to an array,
+you'd have to do something like this:
+
+ while (<>) {
+ push @$ref_to_AoA, [ split ];
+ }
+
+Now you can add new rows. What about adding new columns? If you're
+dealing with just matrices, it's often easiest to use simple assignment:
+
+ for $x (1 .. 10) {
+ for $y (1 .. 10) {
+ $AoA[$x][$y] = func($x, $y);
+ }
+ }
+
+ for $x ( 3, 7, 9 ) {
+ $AoA[$x][20] += func2($x);
+ }
+
+It doesn't matter whether those elements are already
+there or not: it'll gladly create them for you, setting
+intervening elements to C<undef> as need be.
+
+If you wanted just to append to a row, you'd have
+to do something a bit funnier looking:
+
+ # add new columns to an existing row
+ push @{ $AoA[0] }, "wilma", "betty";
+
+Notice that I I<couldn't> say just:
+
+ push $AoA[0], "wilma", "betty"; # WRONG!
+
+In fact, that wouldn't even compile. How come? Because the argument
+to push() must be a real array, not just a reference to such.
+
+=head2 Access and Printing
+
+Now it's time to print your data structure out. How
+are you going to do that? Well, if you want only one
+of the elements, it's trivial:
+
+ print $AoA[0][0];
+
+If you want to print the whole thing, though, you can't
+say
+
+ print @AoA; # WRONG
+
+because you'll get just references listed, and perl will never
+automatically dereference things for you. Instead, you have to
+roll yourself a loop or two. This prints the whole structure,
+using the shell-style for() construct to loop across the outer
+set of subscripts.
+
+ for $aref ( @AoA ) {
+ print "\t [ @$aref ],\n";
+ }
+
+If you wanted to keep track of subscripts, you might do this:
+
+ for $i ( 0 .. $#AoA ) {
+ print "\t elt $i is [ @{$AoA[$i]} ],\n";
+ }
+
+or maybe even this. Notice the inner loop.
+
+ for $i ( 0 .. $#AoA ) {
+ for $j ( 0 .. $#{$AoA[$i]} ) {
+ print "elt $i $j is $AoA[$i][$j]\n";
+ }
+ }
+
+As you can see, it's getting a bit complicated. That's why
+sometimes is easier to take a temporary on your way through:
+
+ for $i ( 0 .. $#AoA ) {
+ $aref = $AoA[$i];
+ for $j ( 0 .. $#{$aref} ) {
+ print "elt $i $j is $AoA[$i][$j]\n";
+ }
+ }
+
+Hmm... that's still a bit ugly. How about this:
+
+ for $i ( 0 .. $#AoA ) {
+ $aref = $AoA[$i];
+ $n = @$aref - 1;
+ for $j ( 0 .. $n ) {
+ print "elt $i $j is $AoA[$i][$j]\n";
+ }
+ }
+
+=head2 Slices
+
+If you want to get at a slice (part of a row) in a multidimensional
+array, you're going to have to do some fancy subscripting. That's
+because while we have a nice synonym for single elements via the
+pointer arrow for dereferencing, no such convenience exists for slices.
+(Remember, of course, that you can always write a loop to do a slice
+operation.)
+
+Here's how to do one operation using a loop. We'll assume an @AoA
+variable as before.
+
+ @part = ();
+ $x = 4;
+ for ($y = 7; $y < 13; $y++) {
+ push @part, $AoA[$x][$y];
+ }
+
+That same loop could be replaced with a slice operation:
+
+ @part = @{ $AoA[4] } [ 7..12 ];
+
+but as you might well imagine, this is pretty rough on the reader.
+
+Ah, but what if you wanted a I<two-dimensional slice>, such as having
+$x run from 4..8 and $y run from 7 to 12? Hmm... here's the simple way:
+
+ @newAoA = ();
+ for ($startx = $x = 4; $x <= 8; $x++) {
+ for ($starty = $y = 7; $y <= 12; $y++) {
+ $newAoA[$x - $startx][$y - $starty] = $AoA[$x][$y];
+ }
+ }
+
+We can reduce some of the looping through slices
+
+ for ($x = 4; $x <= 8; $x++) {
+ push @newAoA, [ @{ $AoA[$x] } [ 7..12 ] ];
+ }
+
+If you were into Schwartzian Transforms, you would probably
+have selected map for that
+
+ @newAoA = map { [ @{ $AoA[$_] } [ 7..12 ] ] } 4 .. 8;
+
+Although if your manager accused you of seeking job security (or rapid
+insecurity) through inscrutable code, it would be hard to argue. :-)
+If I were you, I'd put that in a function:
+
+ @newAoA = splice_2D( \@AoA, 4 => 8, 7 => 12 );
+ sub splice_2D {
+ my $lrr = shift; # ref to array of array refs!
+ my ($x_lo, $x_hi,
+ $y_lo, $y_hi) = @_;
+
+ return map {
+ [ @{ $lrr->[$_] } [ $y_lo .. $y_hi ] ]
+ } $x_lo .. $x_hi;
+ }
+
+
+=head1 SEE ALSO
+
+L<perldata>, L<perlref>, L<perldsc>
+
+=head1 AUTHOR
+
+Tom Christiansen <F<tchrist@perl.com>>
+
+Last update: Thu Jun 4 16:16:23 MDT 1998
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmacos.pod b/Master/tlpkg/tlperl/lib/pods/perlmacos.pod
new file mode 100644
index 00000000000..8c0a66fa601
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmacos.pod
@@ -0,0 +1,34 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.macos - Perl under Mac OS (Classic)
+
+=head1 SYNOPSIS
+
+This document briefly describes perl under Mac OS (Classic).
+If you are running perl under Mac OS X, you don't want to be
+here (unless you are in the Classic environment under early versions of
+Mac OS X).
+
+When we say "Mac OS" below, we mean Mac OS 7, 8, and 9, and I<not>
+Mac OS X.
+
+
+=head1 DESCRIPTION
+
+The port of Perl to to Mac OS was officially removed as of Perl 5.12,
+though the last offical production release of MacPerl corresponded to
+Perl 5.6. While Perl 5.10 included the port to Mac OS, ExtUtils::MakeMaker,
+a core part of Perl's module installation infrastructure officially dropped support for Mac OS in April 2004.
+
+Historical information (and working binaries of the last released version)
+are available from L<http://dev.macperl.org> as of October 2009.
+
+=head1 AUTHOR
+
+perl was ported to Mac OS by Matthias Neeracher
+E<lt>neeracher@mac.comE<gt>. Chris Nandor E<lt>pudge@pobox.comE<gt>
+continued development and maintenance for the duration of the port's life.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmacosx.pod b/Master/tlpkg/tlperl/lib/pods/perlmacosx.pod
new file mode 100644
index 00000000000..a0b21af8c7b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmacosx.pod
@@ -0,0 +1,270 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.macosx - Perl under Mac OS X
+
+=head1 SYNOPSIS
+
+This document briefly describes perl under Mac OS X.
+
+
+=head1 DESCRIPTION
+
+The latest Perl release (5.8.8 as of this writing) builds without changes
+under Mac OS X. Under 10.3 "Panther" and newer OS versions, all self-tests
+pass, and all standard features are supported.
+
+Earlier Mac OS X releases (10.2 "Jaguar" and older) did not include a
+completely thread-safe libc, so threading is not fully supported. Also,
+earlier releases included a buggy libdb, so some of the DB_File tests
+are known to fail on those releases.
+
+
+=head2 Installation Prefix
+
+The default installation location for this release uses the traditional
+UNIX directory layout under /usr/local. This is the recommended location
+for most users, and will leave the Apple-supplied Perl and its modules
+undisturbed.
+
+Using an installation prefix of '/usr' will result in a directory layout
+that mirrors that of Apple's default Perl, with core modules stored in
+'/System/Library/Perl/${version}', CPAN modules stored in
+'/Library/Perl/${version}', and the addition of
+'/Network/Library/Perl/${version}' to @INC for modules that are stored
+on a file server and used by many Macs.
+
+
+=head2 SDK support
+
+First, export the path to the SDK into the build environment:
+
+ export SDK=/Developer/SDKs/MacOSX10.3.9.sdk
+
+Use an SDK by exporting some additions to Perl's 'ccflags' and '..flags'
+config variables:
+
+ ./Configure -Accflags="-nostdinc -B$SDK/usr/include/gcc \
+ -B$SDK/usr/lib/gcc -isystem$SDK/usr/include \
+ -F$SDK/System/Library/Frameworks" \
+ -Aldflags="-Wl,-syslibroot,$SDK" \
+ -de
+
+=head2 Universal Binary support
+
+To compile perl as a universal binary (built for both ppc and intel), export
+the SDK variable as above, selecting the 10.4u SDK:
+
+ export SDK=/Developer/SDKs/MacOSX10.4u.sdk
+
+In addition to the compiler flags used to select the SDK, also add the flags
+for creating a universal binary:
+
+ ./Configure -Accflags="-arch i686 -arch ppc -nostdinc -B$SDK/usr/include/gcc \
+ -B$SDK/usr/lib/gcc -isystem$SDK/usr/include \
+ -F$SDK/System/Library/Frameworks" \
+ -Aldflags="-arch i686 -arch ppc -Wl,-syslibroot,$SDK" \
+ -de
+
+In Leopard (MacOSX 10.5.6 at the time of this writing) you must use the 10.5 SDK:
+
+ export SDK=/Developer/SDKs/MacOSX10.5.sdk
+
+You can use the same compiler flags you would use with the 10.4u SDK.
+
+Keep in mind that these compiler and linker settings will also be used when
+building CPAN modules. For XS modules to be compiled as a universal binary, any
+libraries it links to must also be universal binaries. The system libraries that
+Apple includes with the 10.4u SDK are all universal, but user-installed libraries
+may need to be re-installed as universal binaries.
+
+=head2 64-bit PPC support
+
+Follow the instructions in F<INSTALL> to build perl with support for 64-bit
+integers (C<use64bitint>) or both 64-bit integers and 64-bit addressing
+(C<use64bitall>). In the latter case, the resulting binary will run only
+on G5-based hosts.
+
+Support for 64-bit addressing is experimental: some aspects of Perl may be
+omitted or buggy. Note the messages output by F<Configure> for further
+information. Please use C<perlbug> to submit a problem report in the
+event that you encounter difficulties.
+
+When building 64-bit modules, it is your responsiblity to ensure that linked
+external libraries and frameworks provide 64-bit support: if they do not,
+module building may appear to succeed, but attempts to use the module will
+result in run-time dynamic linking errors, and subsequent test failures.
+You can use C<file> to discover the architectures supported by a library:
+
+ $ file libgdbm.3.0.0.dylib
+ libgdbm.3.0.0.dylib: Mach-O fat file with 2 architectures
+ libgdbm.3.0.0.dylib (for architecture ppc): Mach-O dynamically linked shared library ppc
+ libgdbm.3.0.0.dylib (for architecture ppc64): Mach-O 64-bit dynamically linked shared library ppc64
+
+Note that this issue precludes the building of many Macintosh-specific CPAN
+modules (C<Mac::*>), as the required Apple frameworks do not provide PPC64
+support. Similarly, downloads from Fink or Darwinports are unlikely to provide
+64-bit support; the libraries must be rebuilt from source with the appropriate
+compiler and linker flags. For further information, see Apple's
+I<64-Bit Transition Guide> at
+L<http://developer.apple.com/documentation/Darwin/Conceptual/64bitPorting/index.html>.
+
+=head2 libperl and Prebinding
+
+Mac OS X ships with a dynamically-loaded libperl, but the default for
+this release is to compile a static libperl. The reason for this is
+pre-binding. Dynamic libraries can be pre-bound to a specific address in
+memory in order to decrease load time. To do this, one needs to be aware
+of the location and size of all previously-loaded libraries. Apple
+collects this information as part of their overall OS build process, and
+thus has easy access to it when building Perl, but ordinary users would
+need to go to a great deal of effort to obtain the information needed
+for pre-binding.
+
+You can override the default and build a shared libperl if you wish
+(S<Configure ... -Duseshrlib>), but the load time on pre-10.4 OS
+releases will be greater than either the static library, or Apple's
+pre-bound dynamic library.
+
+With 10.4 "Tiger" and newer, Apple has all but eliminated the performance
+penalty for non-prebound libraries.
+
+
+=head2 Updating Apple's Perl
+
+In a word - don't, at least without a *very* good reason. Your scripts
+can just as easily begin with "#!/usr/local/bin/perl" as with
+"#!/usr/bin/perl". Scripts supplied by Apple and other third parties as
+part of installation packages and such have generally only been tested
+with the /usr/bin/perl that's installed by Apple.
+
+If you find that you do need to update the system Perl, one issue worth
+keeping in mind is the question of static vs. dynamic libraries. If you
+upgrade using the default static libperl, you will find that the dynamic
+libperl supplied by Apple will not be deleted. If both libraries are
+present when an application that links against libperl is built, ld will
+link against the dynamic library by default. So, if you need to replace
+Apple's dynamic libperl with a static libperl, you need to be sure to
+delete the older dynamic library after you've installed the update.
+
+
+=head2 Known problems
+
+If you have installed extra libraries such as GDBM through Fink
+(in other words, you have libraries under F</sw/lib>), or libdlcompat
+to F</usr/local/lib>, you may need to be extra careful when running
+Configure to not to confuse Configure and Perl about which libraries
+to use. Being confused will show up for example as "dyld" errors about
+symbol problems, for example during "make test". The safest bet is to run
+Configure as
+
+ Configure ... -Uloclibpth -Dlibpth=/usr/lib
+
+to make Configure look only into the system libraries. If you have some
+extra library directories that you really want to use (such as newer
+Berkeley DB libraries in pre-Panther systems), add those to the libpth:
+
+ Configure ... -Uloclibpth -Dlibpth='/usr/lib /opt/lib'
+
+The default of building Perl statically may cause problems with complex
+applications like Tk: in that case consider building shared Perl
+
+ Configure ... -Duseshrplib
+
+but remember that there's a startup cost to pay in that case (see above
+"libperl and Prebinding").
+
+Starting with Tiger (Mac OS X 10.4), Apple shipped broken locale files for
+the eu_ES locale (Basque-Spain). In previous releases of Perl, this resulted in
+failures in the C<lib/locale> test. These failures have been supressed
+in the current release of Perl by making the test ignore the broken locale.
+If you need to use the eu_ES locale, you should contact Apple support.
+
+=head2 MacPerl
+
+Quite a bit has been written about MacPerl, the Perl distribution for
+"Classic MacOS" - that is, versions 9 and earlier of MacOS. Because it
+runs in environment that's very different from that of UNIX, many things
+are done differently in MacPerl. Modules are installed using a different
+procedure, Perl itself is built differently, path names are different,
+etc.
+
+From the perspective of a Perl programmer, Mac OS X is more like a
+traditional UNIX than Classic MacOS. If you find documentation that
+refers to a special procedure that's needed for MacOS that's drastically
+different from the instructions provided for UNIX, the MacOS
+instructions are quite often intended for MacPerl on Classic MacOS. In
+that case, the correct procedure on Mac OS X is usually to follow the
+UNIX instructions, rather than the MacPerl instructions.
+
+
+=head2 Carbon
+
+MacPerl ships with a number of modules that are used to access the
+classic MacOS toolbox. Many of these modules have been updated to use
+Mac OS X's newer "Carbon" toolbox, and are available from CPAN in the
+"Mac::Carbon" module.
+
+
+=head2 Cocoa
+
+There are two ways to use Cocoa from Perl. Apple's PerlObjCBridge
+module, included with Mac OS X, can be used by standalone scripts to
+access Foundation (i.e. non-GUI) classes and objects.
+
+An alternative is CamelBones, a framework that allows access to both
+Foundation and AppKit classes and objects, so that full GUI applications
+can be built in Perl. CamelBones can be found on SourceForge, at
+L<http://www.sourceforge.net/projects/camelbones/>.
+
+
+=head1 Starting From Scratch
+
+Unfortunately it is not that difficult somehow manage to break one's
+Mac OS X Perl rather severely. If all else fails and you want to
+really, B<REALLY>, start from scratch and remove even your Apple Perl
+installation (which has become corrupted somehow), the following
+instructions should do it. B<Please think twice before following
+these instructions: they are much like conducting brain surgery to
+yourself. Without anesthesia.> We will B<not> come to fix your system
+if you do this.
+
+First, get rid of the libperl.dylib:
+
+ # cd /System/Library/Perl/darwin/CORE
+ # rm libperl.dylib
+
+Then delete every .bundle file found anywhere in the folders:
+
+ /System/Library/Perl
+ /Library/Perl
+
+You can find them for example by
+
+ # find /System/Library/Perl /Library/Perl -name '*.bundle' -print
+
+After this you can either copy Perl from your operating system media
+(you will need at least the /System/Library/Perl and /usr/bin/perl),
+or rebuild Perl from the source code with C<Configure -Dprefix=/usr
+-Dusershrplib> NOTE: the C<-Dprefix=/usr> to replace the system Perl
+works much better with Perl 5.8.1 and later, in Perl 5.8.0 the
+settings were not quite right.
+
+"Pacifist" from CharlesSoft (L<http://www.charlessoft.com/>) is a nice
+way to extract the Perl binaries from the OS media, without having to
+reinstall the entire OS.
+
+
+=head1 AUTHOR
+
+This README was written by Sherm Pendley E<lt>sherm@dot-app.orgE<gt>,
+and subsequently updated by Dominic Dunlop E<lt>domo@computer.orgE<gt>.
+The "Starting From Scratch" recipe was contributed by John Montbriand
+E<lt>montbriand@apple.comE<gt>.
+
+=head1 DATE
+
+Last modified 2006-02-24.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmod.pod b/Master/tlpkg/tlperl/lib/pods/perlmod.pod
new file mode 100644
index 00000000000..eaa8ba91dbf
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmod.pod
@@ -0,0 +1,598 @@
+=head1 NAME
+
+perlmod - Perl modules (packages and symbol tables)
+
+=head1 DESCRIPTION
+
+=head2 Packages
+X<package> X<namespace> X<variable, global> X<global variable> X<global>
+
+Perl provides a mechanism for alternative namespaces to protect
+packages from stomping on each other's variables. In fact, there's
+really no such thing as a global variable in Perl. The package
+statement declares the compilation unit as being in the given
+namespace. The scope of the package declaration is from the
+declaration itself through the end of the enclosing block, C<eval>,
+or file, whichever comes first (the same scope as the my() and
+local() operators). Unqualified dynamic identifiers will be in
+this namespace, except for those few identifiers that if unqualified,
+default to the main package instead of the current one as described
+below. A package statement affects only dynamic variables--including
+those you've used local() on--but I<not> lexical variables created
+with my(). Typically it would be the first declaration in a file
+included by the C<do>, C<require>, or C<use> operators. You can
+switch into a package in more than one place; it merely influences
+which symbol table is used by the compiler for the rest of that
+block. You can refer to variables and filehandles in other packages
+by prefixing the identifier with the package name and a double
+colon: C<$Package::Variable>. If the package name is null, the
+C<main> package is assumed. That is, C<$::sail> is equivalent to
+C<$main::sail>.
+
+The old package delimiter was a single quote, but double colon is now the
+preferred delimiter, in part because it's more readable to humans, and
+in part because it's more readable to B<emacs> macros. It also makes C++
+programmers feel like they know what's going on--as opposed to using the
+single quote as separator, which was there to make Ada programmers feel
+like they knew what was going on. Because the old-fashioned syntax is still
+supported for backwards compatibility, if you try to use a string like
+C<"This is $owner's house">, you'll be accessing C<$owner::s>; that is,
+the $s variable in package C<owner>, which is probably not what you meant.
+Use braces to disambiguate, as in C<"This is ${owner}'s house">.
+X<::> X<'>
+
+Packages may themselves contain package separators, as in
+C<$OUTER::INNER::var>. This implies nothing about the order of
+name lookups, however. There are no relative packages: all symbols
+are either local to the current package, or must be fully qualified
+from the outer package name down. For instance, there is nowhere
+within package C<OUTER> that C<$INNER::var> refers to
+C<$OUTER::INNER::var>. C<INNER> refers to a totally
+separate global package.
+
+Only identifiers starting with letters (or underscore) are stored
+in a package's symbol table. All other symbols are kept in package
+C<main>, including all punctuation variables, like $_. In addition,
+when unqualified, the identifiers STDIN, STDOUT, STDERR, ARGV,
+ARGVOUT, ENV, INC, and SIG are forced to be in package C<main>,
+even when used for other purposes than their built-in ones. If you
+have a package called C<m>, C<s>, or C<y>, then you can't use the
+qualified form of an identifier because it would be instead interpreted
+as a pattern match, a substitution, or a transliteration.
+X<variable, punctuation>
+
+Variables beginning with underscore used to be forced into package
+main, but we decided it was more useful for package writers to be able
+to use leading underscore to indicate private variables and method names.
+However, variables and functions named with a single C<_>, such as
+$_ and C<sub _>, are still forced into the package C<main>. See also
+L<perlvar/"Technical Note on the Syntax of Variable Names">.
+
+C<eval>ed strings are compiled in the package in which the eval() was
+compiled. (Assignments to C<$SIG{}>, however, assume the signal
+handler specified is in the C<main> package. Qualify the signal handler
+name if you wish to have a signal handler in a package.) For an
+example, examine F<perldb.pl> in the Perl library. It initially switches
+to the C<DB> package so that the debugger doesn't interfere with variables
+in the program you are trying to debug. At various points, however, it
+temporarily switches back to the C<main> package to evaluate various
+expressions in the context of the C<main> package (or wherever you came
+from). See L<perldebug>.
+
+The special symbol C<__PACKAGE__> contains the current package, but cannot
+(easily) be used to construct variable names.
+
+See L<perlsub> for other scoping issues related to my() and local(),
+and L<perlref> regarding closures.
+
+=head2 Symbol Tables
+X<symbol table> X<stash> X<%::> X<%main::> X<typeglob> X<glob> X<alias>
+
+The symbol table for a package happens to be stored in the hash of that
+name with two colons appended. The main symbol table's name is thus
+C<%main::>, or C<%::> for short. Likewise the symbol table for the nested
+package mentioned earlier is named C<%OUTER::INNER::>.
+
+The value in each entry of the hash is what you are referring to when you
+use the C<*name> typeglob notation.
+
+ local *main::foo = *main::bar;
+
+You can use this to print out all the variables in a package, for
+instance. The standard but antiquated F<dumpvar.pl> library and
+the CPAN module Devel::Symdump make use of this.
+
+Assignment to a typeglob performs an aliasing operation, i.e.,
+
+ *dick = *richard;
+
+causes variables, subroutines, formats, and file and directory handles
+accessible via the identifier C<richard> also to be accessible via the
+identifier C<dick>. If you want to alias only a particular variable or
+subroutine, assign a reference instead:
+
+ *dick = \$richard;
+
+Which makes $richard and $dick the same variable, but leaves
+@richard and @dick as separate arrays. Tricky, eh?
+
+There is one subtle difference between the following statements:
+
+ *foo = *bar;
+ *foo = \$bar;
+
+C<*foo = *bar> makes the typeglobs themselves synonymous while
+C<*foo = \$bar> makes the SCALAR portions of two distinct typeglobs
+refer to the same scalar value. This means that the following code:
+
+ $bar = 1;
+ *foo = \$bar; # Make $foo an alias for $bar
+
+ {
+ local $bar = 2; # Restrict changes to block
+ print $foo; # Prints '1'!
+ }
+
+Would print '1', because C<$foo> holds a reference to the I<original>
+C<$bar>. The one that was stuffed away by C<local()> and which will be
+restored when the block ends. Because variables are accessed through the
+typeglob, you can use C<*foo = *bar> to create an alias which can be
+localized. (But be aware that this means you can't have a separate
+C<@foo> and C<@bar>, etc.)
+
+What makes all of this important is that the Exporter module uses glob
+aliasing as the import/export mechanism. Whether or not you can properly
+localize a variable that has been exported from a module depends on how
+it was exported:
+
+ @EXPORT = qw($FOO); # Usual form, can't be localized
+ @EXPORT = qw(*FOO); # Can be localized
+
+You can work around the first case by using the fully qualified name
+(C<$Package::FOO>) where you need a local value, or by overriding it
+by saying C<*FOO = *Package::FOO> in your script.
+
+The C<*x = \$y> mechanism may be used to pass and return cheap references
+into or from subroutines if you don't want to copy the whole
+thing. It only works when assigning to dynamic variables, not
+lexicals.
+
+ %some_hash = (); # can't be my()
+ *some_hash = fn( \%another_hash );
+ sub fn {
+ local *hashsym = shift;
+ # now use %hashsym normally, and you
+ # will affect the caller's %another_hash
+ my %nhash = (); # do what you want
+ return \%nhash;
+ }
+
+On return, the reference will overwrite the hash slot in the
+symbol table specified by the *some_hash typeglob. This
+is a somewhat tricky way of passing around references cheaply
+when you don't want to have to remember to dereference variables
+explicitly.
+
+Another use of symbol tables is for making "constant" scalars.
+X<constant> X<scalar, constant>
+
+ *PI = \3.14159265358979;
+
+Now you cannot alter C<$PI>, which is probably a good thing all in all.
+This isn't the same as a constant subroutine, which is subject to
+optimization at compile-time. A constant subroutine is one prototyped
+to take no arguments and to return a constant expression. See
+L<perlsub> for details on these. The C<use constant> pragma is a
+convenient shorthand for these.
+
+You can say C<*foo{PACKAGE}> and C<*foo{NAME}> to find out what name and
+package the *foo symbol table entry comes from. This may be useful
+in a subroutine that gets passed typeglobs as arguments:
+
+ sub identify_typeglob {
+ my $glob = shift;
+ print 'You gave me ', *{$glob}{PACKAGE}, '::', *{$glob}{NAME}, "\n";
+ }
+ identify_typeglob *foo;
+ identify_typeglob *bar::baz;
+
+This prints
+
+ You gave me main::foo
+ You gave me bar::baz
+
+The C<*foo{THING}> notation can also be used to obtain references to the
+individual elements of *foo. See L<perlref>.
+
+Subroutine definitions (and declarations, for that matter) need
+not necessarily be situated in the package whose symbol table they
+occupy. You can define a subroutine outside its package by
+explicitly qualifying the name of the subroutine:
+
+ package main;
+ sub Some_package::foo { ... } # &foo defined in Some_package
+
+This is just a shorthand for a typeglob assignment at compile time:
+
+ BEGIN { *Some_package::foo = sub { ... } }
+
+and is I<not> the same as writing:
+
+ {
+ package Some_package;
+ sub foo { ... }
+ }
+
+In the first two versions, the body of the subroutine is
+lexically in the main package, I<not> in Some_package. So
+something like this:
+
+ package main;
+
+ $Some_package::name = "fred";
+ $main::name = "barney";
+
+ sub Some_package::foo {
+ print "in ", __PACKAGE__, ": \$name is '$name'\n";
+ }
+
+ Some_package::foo();
+
+prints:
+
+ in main: $name is 'barney'
+
+rather than:
+
+ in Some_package: $name is 'fred'
+
+This also has implications for the use of the SUPER:: qualifier
+(see L<perlobj>).
+
+=head2 BEGIN, UNITCHECK, CHECK, INIT and END
+X<BEGIN> X<UNITCHECK> X<CHECK> X<INIT> X<END>
+
+Five specially named code blocks are executed at the beginning and at
+the end of a running Perl program. These are the C<BEGIN>,
+C<UNITCHECK>, C<CHECK>, C<INIT>, and C<END> blocks.
+
+These code blocks can be prefixed with C<sub> to give the appearance of a
+subroutine (although this is not considered good style). One should note
+that these code blocks don't really exist as named subroutines (despite
+their appearance). The thing that gives this away is the fact that you can
+have B<more than one> of these code blocks in a program, and they will get
+B<all> executed at the appropriate moment. So you can't execute any of
+these code blocks by name.
+
+A C<BEGIN> code block is executed as soon as possible, that is, the moment
+it is completely defined, even before the rest of the containing file (or
+string) is parsed. You may have multiple C<BEGIN> blocks within a file (or
+eval'ed string); they will execute in order of definition. Because a C<BEGIN>
+code block executes immediately, it can pull in definitions of subroutines
+and such from other files in time to be visible to the rest of the compile
+and run time. Once a C<BEGIN> has run, it is immediately undefined and any
+code it used is returned to Perl's memory pool.
+
+An C<END> code block is executed as late as possible, that is, after
+perl has finished running the program and just before the interpreter
+is being exited, even if it is exiting as a result of a die() function.
+(But not if it's morphing into another program via C<exec>, or
+being blown out of the water by a signal--you have to trap that yourself
+(if you can).) You may have multiple C<END> blocks within a file--they
+will execute in reverse order of definition; that is: last in, first
+out (LIFO). C<END> blocks are not executed when you run perl with the
+C<-c> switch, or if compilation fails.
+
+Note that C<END> code blocks are B<not> executed at the end of a string
+C<eval()>: if any C<END> code blocks are created in a string C<eval()>,
+they will be executed just as any other C<END> code block of that package
+in LIFO order just before the interpreter is being exited.
+
+Inside an C<END> code block, C<$?> contains the value that the program is
+going to pass to C<exit()>. You can modify C<$?> to change the exit
+value of the program. Beware of changing C<$?> by accident (e.g. by
+running something via C<system>).
+X<$?>
+
+C<UNITCHECK>, C<CHECK> and C<INIT> code blocks are useful to catch the
+transition between the compilation phase and the execution phase of
+the main program.
+
+C<UNITCHECK> blocks are run just after the unit which defined them has
+been compiled. The main program file and each module it loads are
+compilation units, as are string C<eval>s, code compiled using the
+C<(?{ })> construct in a regex, calls to C<do FILE>, C<require FILE>,
+and code after the C<-e> switch on the command line.
+
+C<CHECK> code blocks are run just after the B<initial> Perl compile phase ends
+and before the run time begins, in LIFO order. C<CHECK> code blocks are used
+in the Perl compiler suite to save the compiled state of the program.
+
+C<INIT> blocks are run just before the Perl runtime begins execution, in
+"first in, first out" (FIFO) order.
+
+The C<CHECK> and C<INIT> code blocks will not be executed inside a string
+eval(), if that eval() happens after the end of the main compilation
+phase; that can be a problem in mod_perl and other persistent environments
+which use C<eval STRING> to load code at runtime.
+
+When you use the B<-n> and B<-p> switches to Perl, C<BEGIN> and
+C<END> work just as they do in B<awk>, as a degenerate case.
+Both C<BEGIN> and C<CHECK> blocks are run when you use the B<-c>
+switch for a compile-only syntax check, although your main code
+is not.
+
+The B<begincheck> program makes it all clear, eventually:
+
+ #!/usr/bin/perl
+
+ # begincheck
+
+ print "10. Ordinary code runs at runtime.\n";
+
+ END { print "16. So this is the end of the tale.\n" }
+ INIT { print " 7. INIT blocks run FIFO just before runtime.\n" }
+ UNITCHECK {
+ print " 4. And therefore before any CHECK blocks.\n"
+ }
+ CHECK { print " 6. So this is the sixth line.\n" }
+
+ print "11. It runs in order, of course.\n";
+
+ BEGIN { print " 1. BEGIN blocks run FIFO during compilation.\n" }
+ END { print "15. Read perlmod for the rest of the story.\n" }
+ CHECK { print " 5. CHECK blocks run LIFO after all compilation.\n" }
+ INIT { print " 8. Run this again, using Perl's -c switch.\n" }
+
+ print "12. This is anti-obfuscated code.\n";
+
+ END { print "14. END blocks run LIFO at quitting time.\n" }
+ BEGIN { print " 2. So this line comes out second.\n" }
+ UNITCHECK {
+ print " 3. UNITCHECK blocks run LIFO after each file is compiled.\n"
+ }
+ INIT { print " 9. You'll see the difference right away.\n" }
+
+ print "13. It merely _looks_ like it should be confusing.\n";
+
+ __END__
+
+=head2 Perl Classes
+X<class> X<@ISA>
+
+There is no special class syntax in Perl, but a package may act
+as a class if it provides subroutines to act as methods. Such a
+package may also derive some of its methods from another class (package)
+by listing the other package name(s) in its global @ISA array (which
+must be a package global, not a lexical).
+
+For more on this, see L<perltoot> and L<perlobj>.
+
+=head2 Perl Modules
+X<module>
+
+A module is just a set of related functions in a library file, i.e.,
+a Perl package with the same name as the file. It is specifically
+designed to be reusable by other modules or programs. It may do this
+by providing a mechanism for exporting some of its symbols into the
+symbol table of any package using it, or it may function as a class
+definition and make its semantics available implicitly through
+method calls on the class and its objects, without explicitly
+exporting anything. Or it can do a little of both.
+
+For example, to start a traditional, non-OO module called Some::Module,
+create a file called F<Some/Module.pm> and start with this template:
+
+ package Some::Module; # assumes Some/Module.pm
+
+ use strict;
+ use warnings;
+
+ BEGIN {
+ use Exporter ();
+ our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
+
+ # set the version for version checking
+ $VERSION = 1.00;
+ # if using RCS/CVS, this may be preferred
+ $VERSION = sprintf "%d.%03d", q$Revision: 1.1 $ =~ /(\d+)/g;
+
+ @ISA = qw(Exporter);
+ @EXPORT = qw(&func1 &func2 &func4);
+ %EXPORT_TAGS = ( ); # eg: TAG => [ qw!name1 name2! ],
+
+ # your exported package globals go here,
+ # as well as any optionally exported functions
+ @EXPORT_OK = qw($Var1 %Hashit &func3);
+ }
+ our @EXPORT_OK;
+
+ # exported package globals go here
+ our $Var1;
+ our %Hashit;
+
+ # non-exported package globals go here
+ our @more;
+ our $stuff;
+
+ # initialize package globals, first exported ones
+ $Var1 = '';
+ %Hashit = ();
+
+ # then the others (which are still accessible as $Some::Module::stuff)
+ $stuff = '';
+ @more = ();
+
+ # all file-scoped lexicals must be created before
+ # the functions below that use them.
+
+ # file-private lexicals go here
+ my $priv_var = '';
+ my %secret_hash = ();
+
+ # here's a file-private function as a closure,
+ # callable as &$priv_func; it cannot be prototyped.
+ my $priv_func = sub {
+ # stuff goes here.
+ };
+
+ # make all your functions, whether exported or not;
+ # remember to put something interesting in the {} stubs
+ sub func1 {} # no prototype
+ sub func2() {} # proto'd void
+ sub func3($$) {} # proto'd to 2 scalars
+
+ # this one isn't exported, but could be called!
+ sub func4(\%) {} # proto'd to 1 hash ref
+
+ END { } # module clean-up code here (global destructor)
+
+ ## YOUR CODE GOES HERE
+
+ 1; # don't forget to return a true value from the file
+
+Then go on to declare and use your variables in functions without
+any qualifications. See L<Exporter> and the L<perlmodlib> for
+details on mechanics and style issues in module creation.
+
+Perl modules are included into your program by saying
+
+ use Module;
+
+or
+
+ use Module LIST;
+
+This is exactly equivalent to
+
+ BEGIN { require Module; import Module; }
+
+or
+
+ BEGIN { require Module; import Module LIST; }
+
+As a special case
+
+ use Module ();
+
+is exactly equivalent to
+
+ BEGIN { require Module; }
+
+All Perl module files have the extension F<.pm>. The C<use> operator
+assumes this so you don't have to spell out "F<Module.pm>" in quotes.
+This also helps to differentiate new modules from old F<.pl> and
+F<.ph> files. Module names are also capitalized unless they're
+functioning as pragmas; pragmas are in effect compiler directives,
+and are sometimes called "pragmatic modules" (or even "pragmata"
+if you're a classicist).
+
+The two statements:
+
+ require SomeModule;
+ require "SomeModule.pm";
+
+differ from each other in two ways. In the first case, any double
+colons in the module name, such as C<Some::Module>, are translated
+into your system's directory separator, usually "/". The second
+case does not, and would have to be specified literally. The other
+difference is that seeing the first C<require> clues in the compiler
+that uses of indirect object notation involving "SomeModule", as
+in C<$ob = purge SomeModule>, are method calls, not function calls.
+(Yes, this really can make a difference.)
+
+Because the C<use> statement implies a C<BEGIN> block, the importing
+of semantics happens as soon as the C<use> statement is compiled,
+before the rest of the file is compiled. This is how it is able
+to function as a pragma mechanism, and also how modules are able to
+declare subroutines that are then visible as list or unary operators for
+the rest of the current file. This will not work if you use C<require>
+instead of C<use>. With C<require> you can get into this problem:
+
+ require Cwd; # make Cwd:: accessible
+ $here = Cwd::getcwd();
+
+ use Cwd; # import names from Cwd::
+ $here = getcwd();
+
+ require Cwd; # make Cwd:: accessible
+ $here = getcwd(); # oops! no main::getcwd()
+
+In general, C<use Module ()> is recommended over C<require Module>,
+because it determines module availability at compile time, not in the
+middle of your program's execution. An exception would be if two modules
+each tried to C<use> each other, and each also called a function from
+that other module. In that case, it's easy to use C<require> instead.
+
+Perl packages may be nested inside other package names, so we can have
+package names containing C<::>. But if we used that package name
+directly as a filename it would make for unwieldy or impossible
+filenames on some systems. Therefore, if a module's name is, say,
+C<Text::Soundex>, then its definition is actually found in the library
+file F<Text/Soundex.pm>.
+
+Perl modules always have a F<.pm> file, but there may also be
+dynamically linked executables (often ending in F<.so>) or autoloaded
+subroutine definitions (often ending in F<.al>) associated with the
+module. If so, these will be entirely transparent to the user of
+the module. It is the responsibility of the F<.pm> file to load
+(or arrange to autoload) any additional functionality. For example,
+although the POSIX module happens to do both dynamic loading and
+autoloading, the user can say just C<use POSIX> to get it all.
+
+=head2 Making your module threadsafe
+X<threadsafe> X<thread safe>
+X<module, threadsafe> X<module, thread safe>
+X<CLONE> X<CLONE_SKIP> X<thread> X<threads> X<ithread>
+
+Since 5.6.0, Perl has had support for a new type of threads called
+interpreter threads (ithreads). These threads can be used explicitly
+and implicitly.
+
+Ithreads work by cloning the data tree so that no data is shared
+between different threads. These threads can be used by using the C<threads>
+module or by doing fork() on win32 (fake fork() support). When a
+thread is cloned all Perl data is cloned, however non-Perl data cannot
+be cloned automatically. Perl after 5.7.2 has support for the C<CLONE>
+special subroutine. In C<CLONE> you can do whatever
+you need to do,
+like for example handle the cloning of non-Perl data, if necessary.
+C<CLONE> will be called once as a class method for every package that has it
+defined (or inherits it). It will be called in the context of the new thread,
+so all modifications are made in the new area. Currently CLONE is called with
+no parameters other than the invocant package name, but code should not assume
+that this will remain unchanged, as it is likely that in future extra parameters
+will be passed in to give more information about the state of cloning.
+
+If you want to CLONE all objects you will need to keep track of them per
+package. This is simply done using a hash and Scalar::Util::weaken().
+
+Perl after 5.8.7 has support for the C<CLONE_SKIP> special subroutine.
+Like C<CLONE>, C<CLONE_SKIP> is called once per package; however, it is
+called just before cloning starts, and in the context of the parent
+thread. If it returns a true value, then no objects of that class will
+be cloned; or rather, they will be copied as unblessed, undef values.
+For example: if in the parent there are two references to a single blessed
+hash, then in the child there will be two references to a single undefined
+scalar value instead.
+This provides a simple mechanism for making a module threadsafe; just add
+C<sub CLONE_SKIP { 1 }> at the top of the class, and C<DESTROY()> will be
+now only be called once per object. Of course, if the child thread needs
+to make use of the objects, then a more sophisticated approach is
+needed.
+
+Like C<CLONE>, C<CLONE_SKIP> is currently called with no parameters other
+than the invocant package name, although that may change. Similarly, to
+allow for future expansion, the return value should be a single C<0> or
+C<1> value.
+
+=head1 SEE ALSO
+
+See L<perlmodlib> for general style issues related to building Perl
+modules and classes, as well as descriptions of the standard library
+and CPAN, L<Exporter> for how Perl's standard import/export mechanism
+works, L<perltoot> and L<perltooc> for an in-depth tutorial on
+creating classes, L<perlobj> for a hard-core reference document on
+objects, L<perlsub> for an explanation of functions and scoping,
+and L<perlxstut> and L<perlguts> for more information on writing
+extension modules.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmodinstall.pod b/Master/tlpkg/tlperl/lib/pods/perlmodinstall.pod
new file mode 100644
index 00000000000..a7b74be9df4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmodinstall.pod
@@ -0,0 +1,454 @@
+=head1 NAME
+
+perlmodinstall - Installing CPAN Modules
+
+=head1 DESCRIPTION
+
+You can think of a module as the fundamental unit of reusable Perl
+code; see L<perlmod> for details. Whenever anyone creates a chunk of
+Perl code that they think will be useful to the world, they register
+as a Perl developer at http://www.cpan.org/modules/04pause.html
+so that they can then upload their code to the CPAN. The CPAN is the
+Comprehensive Perl Archive Network and can be accessed at
+http://www.cpan.org/ , and searched at http://search.cpan.org/ .
+
+This documentation is for people who want to download CPAN modules
+and install them on their own computer.
+
+=head2 PREAMBLE
+
+First, are you sure that the module isn't already on your system? Try
+C<perl -MFoo -e 1>. (Replace "Foo" with the name of the module; for
+instance, C<perl -MCGI::Carp -e 1>.
+
+If you don't see an error message, you have the module. (If you do
+see an error message, it's still possible you have the module, but
+that it's not in your path, which you can display with C<perl -e
+"print qq(@INC)">.) For the remainder of this document, we'll assume
+that you really honestly truly lack an installed module, but have
+found it on the CPAN.
+
+So now you have a file ending in .tar.gz (or, less often, .zip). You
+know there's a tasty module inside. There are four steps you must now
+take:
+
+=over 5
+
+=item B<DECOMPRESS> the file
+
+=item B<UNPACK> the file into a directory
+
+=item B<BUILD> the module (sometimes unnecessary)
+
+=item B<INSTALL> the module.
+
+=back
+
+Here's how to perform each step for each operating system. This is
+<not> a substitute for reading the README and INSTALL files that
+might have come with your module!
+
+Also note that these instructions are tailored for installing the
+module into your system's repository of Perl modules, but you can
+install modules into any directory you wish. For instance, where I
+say C<perl Makefile.PL>, you can substitute C<perl Makefile.PL
+PREFIX=/my/perl_directory> to install the modules into
+C</my/perl_directory>. Then you can use the modules from your Perl
+programs with C<use lib "/my/perl_directory/lib/site_perl";> or
+sometimes just C<use "/my/perl_directory";>. If you're on a system
+that requires superuser/root access to install modules into the
+directories you see when you type C<perl -e "print qq(@INC)">, you'll
+want to install them into a local directory (such as your home
+directory) and use this approach.
+
+=over 4
+
+=item *
+
+B<If you're on a Unix or Unix-like system,>
+
+You can use Andreas Koenig's CPAN module
+( http://www.cpan.org/modules/by-module/CPAN )
+to automate the following steps, from DECOMPRESS through INSTALL.
+
+A. DECOMPRESS
+
+Decompress the file with C<gzip -d yourmodule.tar.gz>
+
+You can get gzip from ftp://prep.ai.mit.edu/pub/gnu/
+
+Or, you can combine this step with the next to save disk space:
+
+ gzip -dc yourmodule.tar.gz | tar -xof -
+
+B. UNPACK
+
+Unpack the result with C<tar -xof yourmodule.tar>
+
+C. BUILD
+
+Go into the newly-created directory and type:
+
+ perl Makefile.PL
+ make test
+
+or
+
+ perl Makefile.PL PREFIX=/my/perl_directory
+
+to install it locally. (Remember that if you do this, you'll have to
+put C<use lib "/my/perl_directory";> near the top of the program that
+is to use this module.
+
+D. INSTALL
+
+While still in that directory, type:
+
+ make install
+
+Make sure you have the appropriate permissions to install the module
+in your Perl 5 library directory. Often, you'll need to be root.
+
+That's all you need to do on Unix systems with dynamic linking.
+Most Unix systems have dynamic linking. If yours doesn't, or if for
+another reason you have a statically-linked perl, B<and> the
+module requires compilation, you'll need to build a new Perl binary
+that includes the module. Again, you'll probably need to be root.
+
+=item *
+
+B<If you're running ActivePerl (Win95/98/2K/NT/XP, Linux, Solaris)>
+
+First, type C<ppm> from a shell and see whether ActiveState's PPM
+repository has your module. If so, you can install it with C<ppm> and
+you won't have to bother with any of the other steps here. You might
+be able to use the CPAN instructions from the "Unix or Linux" section
+above as well; give it a try. Otherwise, you'll have to follow the
+steps below.
+
+ A. DECOMPRESS
+
+You can use the shareware Winzip ( http://www.winzip.com ) to
+decompress and unpack modules.
+
+ B. UNPACK
+
+If you used WinZip, this was already done for you.
+
+ C. BUILD
+
+You'll need the C<nmake> utility, available at
+http://download.microsoft.com/download/vc15/Patch/1.52/W95/EN-US/nmake15.exe
+or dmake, available on CPAN.
+http://search.cpan.org/dist/dmake/
+
+Does the module require compilation (i.e. does it have files that end
+in .xs, .c, .h, .y, .cc, .cxx, or .C)? If it does, life is now
+officially tough for you, because you have to compile the module
+yourself (no easy feat on Windows). You'll need a compiler such as
+Visual C++. Alternatively, you can download a pre-built PPM package
+from ActiveState.
+http://aspn.activestate.com/ASPN/Downloads/ActivePerl/PPM/
+
+Go into the newly-created directory and type:
+
+ perl Makefile.PL
+ nmake test
+
+
+ D. INSTALL
+
+While still in that directory, type:
+
+ nmake install
+
+=item *
+
+B<If you're using a Macintosh with "Classic" MacOS and MacPerl,>
+
+
+A. DECOMPRESS
+
+First, make sure you have the latest B<cpan-mac> distribution (
+http://www.cpan.org/authors/id/CNANDOR/ ), which has utilities for
+doing all of the steps. Read the cpan-mac directions carefully and
+install it. If you choose not to use cpan-mac for some reason, there
+are alternatives listed here.
+
+After installing cpan-mac, drop the module archive on the
+B<untarzipme> droplet, which will decompress and unpack for you.
+
+B<Or>, you can either use the shareware B<StuffIt Expander> program
+( http://my.smithmicro.com/mac/stuffit/ )
+or the freeware B<MacGzip> program (
+http://persephone.cps.unizar.es/general/gente/spd/gzip/gzip.html ).
+
+B. UNPACK
+
+If you're using untarzipme or StuffIt, the archive should be extracted
+now. B<Or>, you can use the freeware B<suntar> or I<Tar> (
+http://hyperarchive.lcs.mit.edu/HyperArchive/Archive/cmp/ ).
+
+C. BUILD
+
+Check the contents of the distribution.
+Read the module's documentation, looking for
+reasons why you might have trouble using it with MacPerl. Look for
+F<.xs> and F<.c> files, which normally denote that the distribution
+must be compiled, and you cannot install it "out of the box."
+(See L<"PORTABILITY">.)
+
+D. INSTALL
+
+If you are using cpan-mac, just drop the folder on the
+B<installme> droplet, and use the module.
+
+B<Or>, if you aren't using cpan-mac, do some manual labor.
+
+Make sure the newlines for the modules are in Mac format, not Unix format.
+If they are not then you might have decompressed them incorrectly. Check
+your decompression and unpacking utilities settings to make sure they are
+translating text files properly.
+
+As a last resort, you can use the perl one-liner:
+
+ perl -i.bak -pe 's/(?:\015)?\012/\015/g' <filenames>
+
+on the source files.
+
+Then move the files (probably just the F<.pm> files, though there
+may be some additional ones, too; check the module documentation)
+to their final destination: This will
+most likely be in C<$ENV{MACPERL}site_lib:> (i.e.,
+C<HD:MacPerl folder:site_lib:>). You can add new paths to
+the default C<@INC> in the Preferences menu item in the
+MacPerl application (C<$ENV{MACPERL}site_lib:> is added
+automagically). Create whatever directory structures are required
+(i.e., for C<Some::Module>, create
+C<$ENV{MACPERL}site_lib:Some:> and put
+C<Module.pm> in that directory).
+
+Then run the following script (or something like it):
+
+ #!perl -w
+ use AutoSplit;
+ my $dir = "${MACPERL}site_perl";
+ autosplit("$dir:Some:Module.pm", "$dir:auto", 0, 1, 1);
+
+=item *
+
+B<If you're on the DJGPP port of DOS,>
+
+ A. DECOMPRESS
+
+djtarx ( ftp://ftp.delorie.com/pub/djgpp/current/v2/ )
+will both uncompress and unpack.
+
+ B. UNPACK
+
+See above.
+
+ C. BUILD
+
+Go into the newly-created directory and type:
+
+ perl Makefile.PL
+ make test
+
+You will need the packages mentioned in F<README.dos>
+in the Perl distribution.
+
+ D. INSTALL
+
+While still in that directory, type:
+
+ make install
+
+You will need the packages mentioned in F<README.dos> in the Perl distribution.
+
+=item *
+
+B<If you're on OS/2,>
+
+Get the EMX development suite and gzip/tar, from either Hobbes (
+http://hobbes.nmsu.edu ) or Leo ( http://www.leo.org ), and then follow
+the instructions for Unix.
+
+=item *
+
+B<If you're on VMS,>
+
+When downloading from CPAN, save your file with a C<.tgz>
+extension instead of C<.tar.gz>. All other periods in the
+filename should be replaced with underscores. For example,
+C<Your-Module-1.33.tar.gz> should be downloaded as
+C<Your-Module-1_33.tgz>.
+
+A. DECOMPRESS
+
+Type
+
+ gzip -d Your-Module.tgz
+
+or, for zipped modules, type
+
+ unzip Your-Module.zip
+
+Executables for gzip, zip, and VMStar:
+
+ http://www.hp.com/go/openvms/freeware/
+
+and their source code:
+
+ http://www.fsf.org/order/ftp.html
+
+Note that GNU's gzip/gunzip is not the same as Info-ZIP's zip/unzip
+package. The former is a simple compression tool; the latter permits
+creation of multi-file archives.
+
+B. UNPACK
+
+If you're using VMStar:
+
+ VMStar xf Your-Module.tar
+
+Or, if you're fond of VMS command syntax:
+
+ tar/extract/verbose Your_Module.tar
+
+C. BUILD
+
+Make sure you have MMS (from Digital) or the freeware MMK ( available
+from MadGoat at http://www.madgoat.com ). Then type this to create
+the DESCRIP.MMS for the module:
+
+ perl Makefile.PL
+
+Now you're ready to build:
+
+ mms test
+
+Substitute C<mmk> for C<mms> above if you're using MMK.
+
+D. INSTALL
+
+Type
+
+ mms install
+
+Substitute C<mmk> for C<mms> above if you're using MMK.
+
+=item *
+
+B<If you're on MVS>,
+
+Introduce the F<.tar.gz> file into an HFS as binary; don't translate from
+ASCII to EBCDIC.
+
+A. DECOMPRESS
+
+Decompress the file with C<gzip -d yourmodule.tar.gz>
+
+You can get gzip from
+http://www.s390.ibm.com/products/oe/bpxqp1.html
+
+B. UNPACK
+
+Unpack the result with
+
+ pax -o to=IBM-1047,from=ISO8859-1 -r < yourmodule.tar
+
+The BUILD and INSTALL steps are identical to those for Unix. Some
+modules generate Makefiles that work better with GNU make, which is
+available from http://www.mks.com/s390/gnu/
+
+=back
+
+=head1 PORTABILITY
+
+Note that not all modules will work with on all platforms.
+See L<perlport> for more information on portability issues.
+Read the documentation to see if the module will work on your
+system. There are basically three categories
+of modules that will not work "out of the box" with all
+platforms (with some possibility of overlap):
+
+=over 4
+
+=item *
+
+B<Those that should, but don't.> These need to be fixed; consider
+contacting the author and possibly writing a patch.
+
+=item *
+
+B<Those that need to be compiled, where the target platform
+doesn't have compilers readily available.> (These modules contain
+F<.xs> or F<.c> files, usually.) You might be able to find
+existing binaries on the CPAN or elsewhere, or you might
+want to try getting compilers and building it yourself, and then
+release the binary for other poor souls to use.
+
+=item *
+
+B<Those that are targeted at a specific platform.>
+(Such as the Win32:: modules.) If the module is targeted
+specifically at a platform other than yours, you're out
+of luck, most likely.
+
+=back
+
+
+
+Check the CPAN Testers if a module should work with your platform
+but it doesn't behave as you'd expect, or you aren't sure whether or
+not a module will work under your platform. If the module you want
+isn't listed there, you can test it yourself and let CPAN Testers know,
+you can join CPAN Testers, or you can request it be tested.
+
+ http://testers.cpan.org/
+
+
+=head1 HEY
+
+If you have any suggested changes for this page, let me know. Please
+don't send me mail asking for help on how to install your modules.
+There are too many modules, and too few Orwants, for me to be able to
+answer or even acknowledge all your questions. Contact the module
+author instead, or post to comp.lang.perl.modules, or ask someone
+familiar with Perl on your operating system.
+
+=head1 AUTHOR
+
+Jon Orwant
+
+orwant@medita.mit.edu
+
+with invaluable help from Chris Nandor, and valuable help from Brandon
+Allbery, Charles Bailey, Graham Barr, Dominic Dunlop, Jarkko
+Hietaniemi, Ben Holzman, Tom Horsley, Nick Ing-Simmons, Tuomas
+J. Lukka, Laszlo Molnar, Alan Olsen, Peter Prymmer, Gurusamy Sarathy,
+Christoph Spalinger, Dan Sugalski, Larry Virden, and Ilya Zakharevich.
+
+First version July 22, 1998; last revised November 21, 2001.
+
+=head1 COPYRIGHT
+
+Copyright (C) 1998, 2002, 2003 Jon Orwant. All Rights Reserved.
+
+Permission is granted to make and distribute verbatim copies of this
+documentation provided the copyright notice and this permission notice are
+preserved on all copies.
+
+Permission is granted to copy and distribute modified versions of this
+documentation under the conditions for verbatim copying, provided also
+that they are marked clearly as modified versions, that the authors'
+names and title are unchanged (though subtitles and additional
+authors' names may be added), and that the entire resulting derived
+work is distributed under the terms of a permission notice identical
+to this one.
+
+Permission is granted to copy and distribute translations of this
+documentation into another language, under the above conditions for
+modified versions.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmodlib.pod b/Master/tlpkg/tlperl/lib/pods/perlmodlib.pod
new file mode 100644
index 00000000000..05c2dd5c72b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmodlib.pod
@@ -0,0 +1,3513 @@
+=for maintainers
+Generated by perlmodlib.PL -- DO NOT EDIT!
+
+=head1 NAME
+
+perlmodlib - constructing new Perl modules and finding existing ones
+
+=head1 THE PERL MODULE LIBRARY
+
+Many modules are included in the Perl distribution. These are described
+below, and all end in F<.pm>. You may discover compiled library
+files (usually ending in F<.so>) or small pieces of modules to be
+autoloaded (ending in F<.al>); these were automatically generated
+by the installation process. You may also discover files in the
+library directory that end in either F<.pl> or F<.ph>. These are
+old libraries supplied so that old programs that use them still
+run. The F<.pl> files will all eventually be converted into standard
+modules, and the F<.ph> files made by B<h2ph> will probably end up
+as extension modules made by B<h2xs>. (Some F<.ph> values may
+already be available through the POSIX, Errno, or Fcntl modules.)
+The B<pl2pm> file in the distribution may help in your conversion,
+but it's just a mechanical process and therefore far from bulletproof.
+
+=head2 Pragmatic Modules
+
+They work somewhat like compiler directives (pragmata) in that they
+tend to affect the compilation of your program, and thus will usually
+work well only when used within a C<use>, or C<no>. Most of these
+are lexically scoped, so an inner BLOCK may countermand them
+by saying:
+
+ no integer;
+ no strict 'refs';
+ no warnings;
+
+which lasts until the end of that BLOCK.
+
+Some pragmas are lexically scoped--typically those that affect the
+C<$^H> hints variable. Others affect the current package instead,
+like C<use vars> and C<use subs>, which allow you to predeclare a
+variables or subroutines within a particular I<file> rather than
+just a block. Such declarations are effective for the entire file
+for which they were declared. You cannot rescind them with C<no
+vars> or C<no subs>.
+
+The following pragmas are defined (and have their own documentation).
+
+=over 12
+
+=item attributes
+
+Get/set subroutine or variable attributes
+
+=item autodie
+
+Replace functions with ones that succeed or die with lexical scope
+
+=item autodie::exception
+
+Exceptions from autodying functions.
+
+=item autodie::exception::system
+
+Exceptions from autodying system().
+
+=item autodie::hints
+
+Provide hints about user subroutines to autodie
+
+=item autouse
+
+Postpone load of modules until a function is used
+
+=item base
+
+Establish an ISA relationship with base classes at compile time
+
+=item bigint
+
+Transparent BigInteger support for Perl
+
+=item bignum
+
+Transparent BigNumber support for Perl
+
+=item bigrat
+
+Transparent BigNumber/BigRational support for Perl
+
+=item blib
+
+Use MakeMaker's uninstalled version of a package
+
+=item bytes
+
+Force byte semantics rather than character semantics
+
+=item charnames
+
+Define character names for C<\N{named}> string literal escapes
+
+=item constant
+
+Declare constants
+
+=item deprecate
+
+Perl pragma for deprecating the core version of a module
+
+=item diagnostics
+
+Produce verbose warning diagnostics
+
+=item encoding
+
+Allows you to write your script in non-ascii or non-utf8
+
+=item encoding::warnings
+
+Warn on implicit encoding conversions
+
+=item feature
+
+Enable new features
+
+=item fields
+
+Compile-time class fields
+
+=item filetest
+
+Control the filetest permission operators
+
+=item if
+
+C<use> a Perl module if a condition holds
+
+=item inc::latest
+
+Use modules bundled in inc/ if they are newer than installed ones
+
+=item integer
+
+Use integer arithmetic instead of floating point
+
+=item less
+
+Request less of something
+
+=item lib
+
+Manipulate @INC at compile time
+
+=item locale
+
+Use and avoid POSIX locales for built-in operations
+
+=item mro
+
+Method Resolution Order
+
+=item open
+
+Set default PerlIO layers for input and output
+
+=item ops
+
+Restrict unsafe operations when compiling
+
+=item overload
+
+Package for overloading Perl operations
+
+=item overloading
+
+Lexically control overloading
+
+=item parent
+
+Establish an ISA relationship with base classes at compile time
+
+=item re
+
+Alter regular expression behaviour
+
+=item sigtrap
+
+Enable simple signal handling
+
+=item sort
+
+Control sort() behaviour
+
+=item strict
+
+Restrict unsafe constructs
+
+=item subs
+
+Predeclare sub names
+
+=item threads
+
+Perl interpreter-based threads
+
+=item threads::shared
+
+Perl extension for sharing data structures between threads
+
+=item utf8
+
+Enable/disable UTF-8 (or UTF-EBCDIC) in source code
+
+=item vars
+
+Predeclare global variable names (obsolete)
+
+=item version
+
+Perl extension for Version Objects
+
+=item vmsish
+
+Control VMS-specific language features
+
+=item warnings
+
+Control optional warnings
+
+=item warnings::register
+
+Warnings import function
+
+=back
+
+=head2 Standard Modules
+
+Standard, bundled modules are all expected to behave in a well-defined
+manner with respect to namespace pollution because they use the
+Exporter module. See their own documentation for details.
+
+It's possible that not all modules listed below are installed on your
+system. For example, the GDBM_File module will not be installed if you
+don't have the gdbm library.
+
+=over 12
+
+=item AnyDBM_File
+
+Provide framework for multiple DBMs
+
+=item App::Cpan
+
+Easily interact with CPAN from the command line
+
+=item App::Prove
+
+Implements the C<prove> command.
+
+=item App::Prove::State
+
+State storage for the C<prove> command.
+
+=item App::Prove::State::Result
+
+Individual test suite results.
+
+=item App::Prove::State::Result::Test
+
+Individual test results.
+
+=item Archive::Extract
+
+A generic archive extracting mechanism
+
+=item Archive::Tar
+
+Module for manipulations of tar archives
+
+=item Archive::Tar::File
+
+A subclass for in-memory extracted file from Archive::Tar
+
+=item Attribute::Handlers
+
+Simpler definition of attribute handlers
+
+=item AutoLoader
+
+Load subroutines only on demand
+
+=item AutoSplit
+
+Split a package for autoloading
+
+=item B
+
+The Perl Compiler Backend
+
+=item B::Concise
+
+Walk Perl syntax tree, printing concise info about ops
+
+=item B::Debug
+
+Walk Perl syntax tree, printing debug info about ops
+
+=item B::Deparse
+
+Perl compiler backend to produce perl code
+
+=item B::Lint
+
+Perl lint
+
+=item B::Lint::Debug
+
+Adds debugging stringification to B::
+
+=item B::Showlex
+
+Show lexical variables used in functions or files
+
+=item B::Terse
+
+Walk Perl syntax tree, printing terse info about ops
+
+=item B::Xref
+
+Generates cross reference reports for Perl programs
+
+=item Benchmark
+
+Benchmark running times of Perl code
+
+=item CGI
+
+Handle Common Gateway Interface requests and responses
+
+=item CGI::Apache
+
+Backward compatibility module for CGI.pm
+
+=item CGI::Carp
+
+CGI routines for writing to the HTTPD (or other) error log
+
+=item CGI::Cookie
+
+Interface to Netscape Cookies
+
+=item CGI::Fast
+
+CGI Interface for Fast CGI
+
+=item CGI::Pretty
+
+Module to produce nicely formatted HTML code
+
+=item CGI::Push
+
+Simple Interface to Server Push
+
+=item CGI::Switch
+
+Backward compatibility module for defunct CGI::Switch
+
+=item CGI::Util
+
+Internal utilities used by CGI module
+
+=item CORE
+
+Pseudo-namespace for Perl's core routines
+
+=item CPAN
+
+Query, download and build perl modules from CPAN sites
+
+=item CPAN::API::HOWTO
+
+A recipe book for programming with CPAN.pm
+
+=item CPAN::Distroprefs
+
+Read and match distroprefs
+
+=item CPAN::FirstTime
+
+Utility for CPAN::Config file Initialization
+
+=item CPAN::Kwalify
+
+Interface between CPAN.pm and Kwalify.pm
+
+=item CPAN::Nox
+
+Wrapper around CPAN.pm without using any XS module
+
+=item CPAN::Version
+
+Utility functions to compare CPAN versions
+
+=item CPANPLUS
+
+API & CLI access to the CPAN mirrors
+
+=item CPANPLUS::Dist::Base
+
+Base class for custom distribution classes
+
+=item CPANPLUS::Dist::Build
+
+CPANPLUS plugin to install packages that use Build.PL
+
+=item CPANPLUS::Dist::Build::Constants
+
+Constants for CPANPLUS::Dist::Build
+
+=item CPANPLUS::Dist::Sample
+
+Sample code to create your own Dist::* plugin
+
+=item CPANPLUS::Internals::Source::Memory
+
+In memory implementation
+
+=item CPANPLUS::Internals::Source::SQLite
+
+SQLite implementation
+
+=item CPANPLUS::Shell::Classic
+
+CPAN.pm emulation for CPANPLUS
+
+=item CPANPLUS::Shell::Default::Plugins::HOWTO
+
+Documentation on how to write your own plugins
+
+=item Carp
+
+Warn of errors (from perspective of caller)
+
+=item Class::ISA
+
+Report the search path for a class's ISA tree
+
+=item Class::Struct
+
+Declare struct-like datatypes as Perl classes
+
+=item Compress::Raw::Bzip2
+
+Low-Level Interface to bzip2 compression library
+
+=item Compress::Raw::Bzip2::FAQ
+
+Frequently Asked Questions about Compress::Raw::Bzip2
+
+=item Compress::Raw::Zlib
+
+Low-Level Interface to zlib compression library
+
+=item Compress::Raw::Zlib::FAQ
+
+Frequently Asked Questions about Compress::Raw::Zlib
+
+=item Compress::Zlib
+
+Interface to zlib compression library
+
+=item Config
+
+Access Perl configuration information
+
+=item Cwd
+
+Get pathname of current working directory
+
+=item DB
+
+Programmatic interface to the Perl debugging API
+
+=item DBM_Filter
+
+Filter DBM keys/values
+
+=item DBM_Filter::compress
+
+Filter for DBM_Filter
+
+=item DBM_Filter::encode
+
+Filter for DBM_Filter
+
+=item DBM_Filter::int32
+
+Filter for DBM_Filter
+
+=item DBM_Filter::null
+
+Filter for DBM_Filter
+
+=item DBM_Filter::utf8
+
+Filter for DBM_Filter
+
+=item DB_File
+
+Perl5 access to Berkeley DB version 1.x
+
+=item Data::Dumper
+
+Stringified perl data structures, suitable for both printing and C<eval>
+
+=item Devel::DProf
+
+A Perl code profiler
+
+=item Devel::InnerPackage
+
+Find all the inner packages of a package
+
+=item Devel::PPPort
+
+Perl/Pollution/Portability
+
+=item Devel::Peek
+
+A data debugging tool for the XS programmer
+
+=item Devel::SelfStubber
+
+Generate stubs for a SelfLoading module
+
+=item Digest
+
+Modules that calculate message digests
+
+=item Digest::MD5
+
+Perl interface to the MD5 Algorithm
+
+=item Digest::SHA
+
+Perl extension for SHA-1/224/256/384/512
+
+=item Digest::base
+
+Digest base class
+
+=item Digest::file
+
+Calculate digests of files
+
+=item DirHandle
+
+Supply object methods for directory handles
+
+=item Dumpvalue
+
+Provides screen dump of Perl data.
+
+=item DynaLoader
+
+Dynamically load C libraries into Perl code
+
+=item Encode
+
+Character encodings
+
+=item Encode::Alias
+
+Alias definitions to encodings
+
+=item Encode::Byte
+
+Single Byte Encodings
+
+=item Encode::CJKConstants
+
+Internally used by Encode::??::ISO_2022_*
+
+=item Encode::CN
+
+China-based Chinese Encodings
+
+=item Encode::CN::HZ
+
+Internally used by Encode::CN
+
+=item Encode::Config
+
+Internally used by Encode
+
+=item Encode::EBCDIC
+
+EBCDIC Encodings
+
+=item Encode::Encoder
+
+Object Oriented Encoder
+
+=item Encode::Encoding
+
+Encode Implementation Base Class
+
+=item Encode::GSM0338
+
+ESTI GSM 03.38 Encoding
+
+=item Encode::Guess
+
+Guesses encoding from data
+
+=item Encode::JP
+
+Japanese Encodings
+
+=item Encode::JP::H2Z
+
+Internally used by Encode::JP::2022_JP*
+
+=item Encode::JP::JIS7
+
+Internally used by Encode::JP
+
+=item Encode::KR
+
+Korean Encodings
+
+=item Encode::KR::2022_KR
+
+Internally used by Encode::KR
+
+=item Encode::MIME::Header
+
+MIME 'B' and 'Q' header encoding
+
+=item Encode::MIME::Name
+
+Internally used by Encode
+
+=item Encode::PerlIO
+
+A detailed document on Encode and PerlIO
+
+=item Encode::Supported
+
+Encodings supported by Encode
+
+=item Encode::Symbol
+
+Symbol Encodings
+
+=item Encode::TW
+
+Taiwan-based Chinese Encodings
+
+=item Encode::Unicode
+
+Various Unicode Transformation Formats
+
+=item Encode::Unicode::UTF7
+
+UTF-7 encoding
+
+=item English
+
+Use nice English (or awk) names for ugly punctuation variables
+
+=item Env
+
+Perl module that imports environment variables as scalars or arrays
+
+=item Errno
+
+System errno constants
+
+=item Exporter
+
+Implements default import method for modules
+
+=item Exporter::Heavy
+
+Exporter guts
+
+=item ExtUtils::CBuilder
+
+Compile and link C code for Perl modules
+
+=item ExtUtils::CBuilder::Platform::Windows
+
+Builder class for Windows platforms
+
+=item ExtUtils::Command
+
+Utilities to replace common UNIX commands in Makefiles etc.
+
+=item ExtUtils::Command::MM
+
+Commands for the MM's to use in Makefiles
+
+=item ExtUtils::Constant
+
+Generate XS code to import C header constants
+
+=item ExtUtils::Constant::Base
+
+Base class for ExtUtils::Constant objects
+
+=item ExtUtils::Constant::Utils
+
+Helper functions for ExtUtils::Constant
+
+=item ExtUtils::Constant::XS
+
+Generate C code for XS modules' constants.
+
+=item ExtUtils::Embed
+
+Utilities for embedding Perl in C/C++ applications
+
+=item ExtUtils::Install
+
+Install files from here to there
+
+=item ExtUtils::Installed
+
+Inventory management of installed modules
+
+=item ExtUtils::Liblist
+
+Determine libraries to use and how to use them
+
+=item ExtUtils::MM
+
+OS adjusted ExtUtils::MakeMaker subclass
+
+=item ExtUtils::MM_AIX
+
+AIX specific subclass of ExtUtils::MM_Unix
+
+=item ExtUtils::MM_Any
+
+Platform-agnostic MM methods
+
+=item ExtUtils::MM_BeOS
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_Cygwin
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_DOS
+
+DOS specific subclass of ExtUtils::MM_Unix
+
+=item ExtUtils::MM_Darwin
+
+Special behaviors for OS X
+
+=item ExtUtils::MM_MacOS
+
+Once produced Makefiles for MacOS Classic
+
+=item ExtUtils::MM_NW5
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_OS2
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_QNX
+
+QNX specific subclass of ExtUtils::MM_Unix
+
+=item ExtUtils::MM_UWIN
+
+U/WIN specific subclass of ExtUtils::MM_Unix
+
+=item ExtUtils::MM_Unix
+
+Methods used by ExtUtils::MakeMaker
+
+=item ExtUtils::MM_VMS
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_VOS
+
+VOS specific subclass of ExtUtils::MM_Unix
+
+=item ExtUtils::MM_Win32
+
+Methods to override UN*X behaviour in ExtUtils::MakeMaker
+
+=item ExtUtils::MM_Win95
+
+Method to customize MakeMaker for Win9X
+
+=item ExtUtils::MY
+
+ExtUtils::MakeMaker subclass for customization
+
+=item ExtUtils::MakeMaker
+
+Create a module Makefile
+
+=item ExtUtils::MakeMaker::Config
+
+Wrapper around Config.pm
+
+=item ExtUtils::MakeMaker::FAQ
+
+Frequently Asked Questions About MakeMaker
+
+=item ExtUtils::MakeMaker::Tutorial
+
+Writing a module with MakeMaker
+
+=item ExtUtils::Manifest
+
+Utilities to write and check a MANIFEST file
+
+=item ExtUtils::Mkbootstrap
+
+Make a bootstrap file for use by DynaLoader
+
+=item ExtUtils::Mksymlists
+
+Write linker options files for dynamic extension
+
+=item ExtUtils::Packlist
+
+Manage .packlist files
+
+=item ExtUtils::ParseXS
+
+Converts Perl XS code into C code
+
+=item ExtUtils::XSSymSet
+
+Keep sets of symbol names palatable to the VMS linker
+
+=item ExtUtils::testlib
+
+Add blib/* directories to @INC
+
+=item Fatal
+
+Replace functions with equivalents which succeed or die
+
+=item Fcntl
+
+Load the C Fcntl.h defines
+
+=item File::Basename
+
+Parse file paths into directory, filename and suffix.
+
+=item File::CheckTree
+
+Run many filetest checks on a tree
+
+=item File::Compare
+
+Compare files or filehandles
+
+=item File::Copy
+
+Copy files or filehandles
+
+=item File::DosGlob
+
+DOS like globbing and then some
+
+=item File::Fetch
+
+A generic file fetching mechanism
+
+=item File::Find
+
+Traverse a directory tree.
+
+=item File::Glob
+
+Perl extension for BSD glob routine
+
+=item File::GlobMapper
+
+Extend File Glob to Allow Input and Output Files
+
+=item File::Path
+
+Create or remove directory trees
+
+=item File::Spec
+
+Portably perform operations on file names
+
+=item File::Spec::Cygwin
+
+Methods for Cygwin file specs
+
+=item File::Spec::Epoc
+
+Methods for Epoc file specs
+
+=item File::Spec::Functions
+
+Portably perform operations on file names
+
+=item File::Spec::Mac
+
+File::Spec for Mac OS (Classic)
+
+=item File::Spec::OS2
+
+Methods for OS/2 file specs
+
+=item File::Spec::Unix
+
+File::Spec for Unix, base for other File::Spec modules
+
+=item File::Spec::VMS
+
+Methods for VMS file specs
+
+=item File::Spec::Win32
+
+Methods for Win32 file specs
+
+=item File::Temp
+
+Return name and handle of a temporary file safely
+
+=item File::stat
+
+By-name interface to Perl's built-in stat() functions
+
+=item FileCache
+
+Keep more files open than the system permits
+
+=item FileHandle
+
+Supply object methods for filehandles
+
+=item Filter::Simple
+
+Simplified source filtering
+
+=item Filter::Util::Call
+
+Perl Source Filter Utility Module
+
+=item FindBin
+
+Locate directory of original perl script
+
+=item GDBM_File
+
+Perl5 access to the gdbm library.
+
+=item Getopt::Long
+
+Extended processing of command line options
+
+=item Getopt::Std
+
+Process single-character switches with switch clustering
+
+=item Hash::Util
+
+A selection of general-utility hash subroutines
+
+=item Hash::Util::FieldHash
+
+Support for Inside-Out Classes
+
+=item I18N::Collate
+
+Compare 8-bit scalar data according to the current locale
+
+=item I18N::LangTags
+
+Functions for dealing with RFC3066-style language tags
+
+=item I18N::LangTags::Detect
+
+Detect the user's language preferences
+
+=item I18N::LangTags::List
+
+Tags and names for human languages
+
+=item I18N::Langinfo
+
+Query locale information
+
+=item IO
+
+Load various IO modules
+
+=item IO::Compress::Base
+
+Base Class for IO::Compress modules
+
+=item IO::Compress::Bzip2
+
+Write bzip2 files/buffers
+
+=item IO::Compress::Deflate
+
+Write RFC 1950 files/buffers
+
+=item IO::Compress::FAQ
+
+Frequently Asked Questions about IO::Compress
+
+=item IO::Compress::Gzip
+
+Write RFC 1952 files/buffers
+
+=item IO::Compress::RawDeflate
+
+Write RFC 1951 files/buffers
+
+=item IO::Compress::Zip
+
+Write zip files/buffers
+
+=item IO::Dir
+
+Supply object methods for directory handles
+
+=item IO::File
+
+Supply object methods for filehandles
+
+=item IO::Handle
+
+Supply object methods for I/O handles
+
+=item IO::Pipe
+
+Supply object methods for pipes
+
+=item IO::Poll
+
+Object interface to system poll call
+
+=item IO::Seekable
+
+Supply seek based methods for I/O objects
+
+=item IO::Select
+
+OO interface to the select system call
+
+=item IO::Socket
+
+Object interface to socket communications
+
+=item IO::Socket::INET
+
+Object interface for AF_INET domain sockets
+
+=item IO::Socket::UNIX
+
+Object interface for AF_UNIX domain sockets
+
+=item IO::Uncompress::AnyInflate
+
+Uncompress zlib-based (zip, gzip) file/buffer
+
+=item IO::Uncompress::AnyUncompress
+
+Uncompress gzip, zip, bzip2 or lzop file/buffer
+
+=item IO::Uncompress::Base
+
+Base Class for IO::Uncompress modules
+
+=item IO::Uncompress::Bunzip2
+
+Read bzip2 files/buffers
+
+=item IO::Uncompress::Gunzip
+
+Read RFC 1952 files/buffers
+
+=item IO::Uncompress::Inflate
+
+Read RFC 1950 files/buffers
+
+=item IO::Uncompress::RawInflate
+
+Read RFC 1951 files/buffers
+
+=item IO::Uncompress::Unzip
+
+Read zip files/buffers
+
+=item IO::Zlib
+
+IO:: style interface to L<Compress::Zlib>
+
+=item IPC::Cmd
+
+Finding and running system commands made easy
+
+=item IPC::Msg
+
+SysV Msg IPC object class
+
+=item IPC::Open2
+
+Open a process for both reading and writing using open2()
+
+=item IPC::Open3
+
+Open a process for reading, writing, and error handling using open3()
+
+=item IPC::Semaphore
+
+SysV Semaphore IPC object class
+
+=item IPC::SharedMem
+
+SysV Shared Memory IPC object class
+
+=item IPC::SysV
+
+System V IPC constants and system calls
+
+=item List::Util
+
+A selection of general-utility list subroutines
+
+=item List::Util::XS
+
+Indicate if List::Util was compiled with a C compiler
+
+=item Locale::Constants
+
+Constants for Locale codes
+
+=item Locale::Country
+
+ISO codes for country identification (ISO 3166)
+
+=item Locale::Currency
+
+ISO three letter codes for currency identification (ISO 4217)
+
+=item Locale::Language
+
+ISO two letter codes for language identification (ISO 639)
+
+=item Locale::Maketext
+
+Framework for localization
+
+=item Locale::Maketext::Simple
+
+Simple interface to Locale::Maketext::Lexicon
+
+=item Locale::Maketext::TPJ13
+
+Article about software localization
+
+=item Locale::Script
+
+ISO codes for script identification (ISO 15924)
+
+=item Log::Message
+
+A generic message storing mechanism;
+
+=item Log::Message::Config
+
+Configuration options for Log::Message
+
+=item Log::Message::Handlers
+
+Message handlers for Log::Message
+
+=item Log::Message::Item
+
+Message objects for Log::Message
+
+=item Log::Message::Simple
+
+Simplified interface to Log::Message
+
+=item MIME::Base64
+
+Encoding and decoding of base64 strings
+
+=item MIME::QuotedPrint
+
+Encoding and decoding of quoted-printable strings
+
+=item Math::BigFloat
+
+Arbitrary size floating point math package
+
+=item Math::BigInt
+
+Arbitrary size integer/float math package
+
+=item Math::BigInt::Calc
+
+Pure Perl module to support Math::BigInt
+
+=item Math::BigInt::CalcEmu
+
+Emulate low-level math with BigInt code
+
+=item Math::BigInt::FastCalc
+
+Math::BigInt::Calc with some XS for more speed
+
+=item Math::BigRat
+
+Arbitrary big rational numbers
+
+=item Math::Complex
+
+Complex numbers and associated mathematical functions
+
+=item Math::Trig
+
+Trigonometric functions
+
+=item Memoize
+
+Make functions faster by trading space for time
+
+=item Memoize::AnyDBM_File
+
+Glue to provide EXISTS for AnyDBM_File for Storable use
+
+=item Memoize::Expire
+
+Plug-in module for automatic expiration of memoized values
+
+=item Memoize::ExpireFile
+
+Test for Memoize expiration semantics
+
+=item Memoize::ExpireTest
+
+Test for Memoize expiration semantics
+
+=item Memoize::NDBM_File
+
+Glue to provide EXISTS for NDBM_File for Storable use
+
+=item Memoize::SDBM_File
+
+Glue to provide EXISTS for SDBM_File for Storable use
+
+=item Memoize::Storable
+
+Store Memoized data in Storable database
+
+=item Module::Build
+
+Build and install Perl modules
+
+=item Module::Build::API
+
+API Reference for Module Authors
+
+=item Module::Build::Authoring
+
+Authoring Module::Build modules
+
+=item Module::Build::Base
+
+Default methods for Module::Build
+
+=item Module::Build::Bundling
+
+How to bundle Module::Build with a distribution
+
+=item Module::Build::Compat
+
+Compatibility with ExtUtils::MakeMaker
+
+=item Module::Build::ConfigData
+
+Configuration for Module::Build
+
+=item Module::Build::Cookbook
+
+Examples of Module::Build Usage
+
+=item Module::Build::ModuleInfo
+
+Gather package and POD information from a perl module file
+
+=item Module::Build::Notes
+
+Create persistent distribution configuration modules
+
+=item Module::Build::PPMMaker
+
+Perl Package Manager file creation
+
+=item Module::Build::Platform::Amiga
+
+Builder class for Amiga platforms
+
+=item Module::Build::Platform::Default
+
+Stub class for unknown platforms
+
+=item Module::Build::Platform::EBCDIC
+
+Builder class for EBCDIC platforms
+
+=item Module::Build::Platform::MPEiX
+
+Builder class for MPEiX platforms
+
+=item Module::Build::Platform::MacOS
+
+Builder class for MacOS platforms
+
+=item Module::Build::Platform::RiscOS
+
+Builder class for RiscOS platforms
+
+=item Module::Build::Platform::Unix
+
+Builder class for Unix platforms
+
+=item Module::Build::Platform::VMS
+
+Builder class for VMS platforms
+
+=item Module::Build::Platform::VOS
+
+Builder class for VOS platforms
+
+=item Module::Build::Platform::Windows
+
+Builder class for Windows platforms
+
+=item Module::Build::Platform::aix
+
+Builder class for AIX platform
+
+=item Module::Build::Platform::cygwin
+
+Builder class for Cygwin platform
+
+=item Module::Build::Platform::darwin
+
+Builder class for Mac OS X platform
+
+=item Module::Build::Platform::os2
+
+Builder class for OS/2 platform
+
+=item Module::CoreList
+
+What modules shipped with versions of perl
+
+=item Module::Load
+
+Runtime require of both modules and files
+
+=item Module::Load::Conditional
+
+Looking up module information / loading at runtime
+
+=item Module::Loaded
+
+Mark modules as loaded or unloaded
+
+=item Module::Pluggable
+
+Automatically give your module the ability to have plugins
+
+=item Module::Pluggable::Object
+
+Automatically give your module the ability to have plugins
+
+=item NDBM_File
+
+Tied access to ndbm files
+
+=item NEXT
+
+Provide a pseudo-class NEXT (et al) that allows method redispatch
+
+=item Net::Cmd
+
+Network Command class (as used by FTP, SMTP etc)
+
+=item Net::Config
+
+Local configuration data for libnet
+
+=item Net::Domain
+
+Attempt to evaluate the current host's internet name and domain
+
+=item Net::FTP
+
+FTP Client class
+
+=item Net::NNTP
+
+NNTP Client class
+
+=item Net::Netrc
+
+OO interface to users netrc file
+
+=item Net::POP3
+
+Post Office Protocol 3 Client class (RFC1939)
+
+=item Net::Ping
+
+Check a remote host for reachability
+
+=item Net::SMTP
+
+Simple Mail Transfer Protocol Client
+
+=item Net::Time
+
+Time and daytime network client interface
+
+=item Net::hostent
+
+By-name interface to Perl's built-in gethost*() functions
+
+=item Net::libnetFAQ
+
+Libnet Frequently Asked Questions
+
+=item Net::netent
+
+By-name interface to Perl's built-in getnet*() functions
+
+=item Net::protoent
+
+By-name interface to Perl's built-in getproto*() functions
+
+=item Net::servent
+
+By-name interface to Perl's built-in getserv*() functions
+
+=item O
+
+Generic interface to Perl Compiler backends
+
+=item ODBM_File
+
+Tied access to odbm files
+
+=item Object::Accessor
+
+Interface to create per object accessors
+
+=item Opcode
+
+Disable named opcodes when compiling perl code
+
+=item POSIX
+
+Perl interface to IEEE Std 1003.1
+
+=item Package::Constants
+
+List all constants declared in a package
+
+=item Params::Check
+
+A generic input parsing/checking mechanism.
+
+=item Parse::CPAN::Meta
+
+Parse META.yml and other similar CPAN metadata files
+
+=item PerlIO
+
+On demand loader for PerlIO layers and root of PerlIO::* name space
+
+=item PerlIO::encoding
+
+Encoding layer
+
+=item PerlIO::scalar
+
+In-memory IO, scalar IO
+
+=item PerlIO::via
+
+Helper class for PerlIO layers implemented in perl
+
+=item PerlIO::via::QuotedPrint
+
+PerlIO layer for quoted-printable strings
+
+=item Pod::Checker
+
+Check pod documents for syntax errors
+
+=item Pod::Escapes
+
+For resolving Pod EE<lt>...E<gt> sequences
+
+=item Pod::Find
+
+Find POD documents in directory trees
+
+=item Pod::Functions
+
+Group Perl's functions a la perlfunc.pod
+
+=item Pod::Html
+
+Module to convert pod files to HTML
+
+=item Pod::InputObjects
+
+Objects representing POD input paragraphs, commands, etc.
+
+=item Pod::LaTeX
+
+Convert Pod data to formatted Latex
+
+=item Pod::Man
+
+Convert POD data to formatted *roff input
+
+=item Pod::ParseLink
+
+Parse an LE<lt>E<gt> formatting code in POD text
+
+=item Pod::ParseUtils
+
+Helpers for POD parsing and conversion
+
+=item Pod::Parser
+
+Base class for creating POD filters and translators
+
+=item Pod::Perldoc
+
+Look up Perl documentation in Pod format.
+
+=item Pod::Perldoc::BaseTo
+
+Base for Pod::Perldoc formatters
+
+=item Pod::Perldoc::GetOptsOO
+
+Customized option parser for Pod::Perldoc
+
+=item Pod::Perldoc::ToChecker
+
+Let Perldoc check Pod for errors
+
+=item Pod::Perldoc::ToMan
+
+Let Perldoc render Pod as man pages
+
+=item Pod::Perldoc::ToNroff
+
+Let Perldoc convert Pod to nroff
+
+=item Pod::Perldoc::ToPod
+
+Let Perldoc render Pod as ... Pod!
+
+=item Pod::Perldoc::ToRtf
+
+Let Perldoc render Pod as RTF
+
+=item Pod::Perldoc::ToText
+
+Let Perldoc render Pod as plaintext
+
+=item Pod::Perldoc::ToTk
+
+Let Perldoc use Tk::Pod to render Pod
+
+=item Pod::Perldoc::ToXml
+
+Let Perldoc render Pod as XML
+
+=item Pod::PlainText
+
+Convert POD data to formatted ASCII text
+
+=item Pod::Plainer
+
+Perl extension for converting Pod to old-style Pod.
+
+=item Pod::Select
+
+Extract selected sections of POD from input
+
+=item Pod::Simple
+
+Framework for parsing Pod
+
+=item Pod::Simple::Checker
+
+Check the Pod syntax of a document
+
+=item Pod::Simple::Debug
+
+Put Pod::Simple into trace/debug mode
+
+=item Pod::Simple::DumpAsText
+
+Dump Pod-parsing events as text
+
+=item Pod::Simple::DumpAsXML
+
+Turn Pod into XML
+
+=item Pod::Simple::HTML
+
+Convert Pod to HTML
+
+=item Pod::Simple::HTMLBatch
+
+Convert several Pod files to several HTML files
+
+=item Pod::Simple::LinkSection
+
+Represent "section" attributes of L codes
+
+=item Pod::Simple::Methody
+
+Turn Pod::Simple events into method calls
+
+=item Pod::Simple::PullParser
+
+A pull-parser interface to parsing Pod
+
+=item Pod::Simple::PullParserEndToken
+
+End-tokens from Pod::Simple::PullParser
+
+=item Pod::Simple::PullParserStartToken
+
+Start-tokens from Pod::Simple::PullParser
+
+=item Pod::Simple::PullParserTextToken
+
+Text-tokens from Pod::Simple::PullParser
+
+=item Pod::Simple::PullParserToken
+
+Tokens from Pod::Simple::PullParser
+
+=item Pod::Simple::RTF
+
+Format Pod as RTF
+
+=item Pod::Simple::Search
+
+Find POD documents in directory trees
+
+=item Pod::Simple::SimpleTree
+
+Parse Pod into a simple parse tree
+
+=item Pod::Simple::Subclassing
+
+Write a formatter as a Pod::Simple subclass
+
+=item Pod::Simple::Text
+
+Format Pod as plaintext
+
+=item Pod::Simple::TextContent
+
+Get the text content of Pod
+
+=item Pod::Simple::XHTML
+
+Format Pod as validating XHTML
+
+=item Pod::Simple::XMLOutStream
+
+Turn Pod into XML
+
+=item Pod::Text
+
+Convert POD data to formatted ASCII text
+
+=item Pod::Text::Color
+
+Convert POD data to formatted color ASCII text
+
+=item Pod::Text::Termcap
+
+Convert POD data to ASCII text with format escapes
+
+=item Pod::Usage
+
+Print a usage message from embedded pod documentation
+
+=item SDBM_File
+
+Tied access to sdbm files
+
+=item Safe
+
+Compile and execute code in restricted compartments
+
+=item Scalar::Util
+
+A selection of general-utility scalar subroutines
+
+=item Search::Dict
+
+Search for key in dictionary file
+
+=item SelectSaver
+
+Save and restore selected file handle
+
+=item SelfLoader
+
+Load functions only on demand
+
+=item Shell
+
+Run shell commands transparently within perl
+
+=item Socket
+
+Load the C socket.h defines and structure manipulators
+
+=item Storable
+
+Persistence for Perl data structures
+
+=item Switch
+
+A switch statement for Perl
+
+=item Symbol
+
+Manipulate Perl symbols and their names
+
+=item Sys::Hostname
+
+Try every conceivable way to get hostname
+
+=item Sys::Syslog
+
+Perl interface to the UNIX syslog(3) calls
+
+=item Sys::Syslog::Win32
+
+Win32 support for Sys::Syslog
+
+=item TAP::Base
+
+Base class that provides common functionality to L<TAP::Parser>
+
+=item TAP::Formatter::Color
+
+Run Perl test scripts with color
+
+=item TAP::Formatter::Console
+
+Harness output delegate for default console output
+
+=item TAP::Formatter::Console
+
+Harness output delegate for default console output
+
+=item TAP::Formatter::Console::ParallelSession
+
+Harness output delegate for parallel console output
+
+=item TAP::Formatter::Console::Session
+
+Harness output delegate for default console output
+
+=item TAP::Formatter::File
+
+Harness output delegate for file output
+
+=item TAP::Formatter::File::Session
+
+Harness output delegate for file output
+
+=item TAP::Formatter::Session
+
+Abstract base class for harness output delegate
+
+=item TAP::Harness
+
+Run test scripts with statistics
+
+=item TAP::Object
+
+Base class that provides common functionality to all C<TAP::*> modules
+
+=item TAP::Parser
+
+Parse L<TAP|Test::Harness::TAP> output
+
+=item TAP::Parser::Aggregator
+
+Aggregate TAP::Parser results
+
+=item TAP::Parser::Grammar
+
+A grammar for the Test Anything Protocol.
+
+=item TAP::Parser::Iterator
+
+Internal base class for TAP::Parser Iterators
+
+=item TAP::Parser::Iterator::Array
+
+Internal TAP::Parser array Iterator
+
+=item TAP::Parser::Iterator::Process
+
+Internal TAP::Parser Iterator
+
+=item TAP::Parser::Iterator::Stream
+
+Internal TAP::Parser Iterator
+
+=item TAP::Parser::IteratorFactory
+
+Internal TAP::Parser Iterator
+
+=item TAP::Parser::Multiplexer
+
+Multiplex multiple TAP::Parsers
+
+=item TAP::Parser::Result
+
+Base class for TAP::Parser output objects
+
+=item TAP::Parser::Result::Bailout
+
+Bailout result token.
+
+=item TAP::Parser::Result::Comment
+
+Comment result token.
+
+=item TAP::Parser::Result::Plan
+
+Plan result token.
+
+=item TAP::Parser::Result::Pragma
+
+TAP pragma token.
+
+=item TAP::Parser::Result::Test
+
+Test result token.
+
+=item TAP::Parser::Result::Unknown
+
+Unknown result token.
+
+=item TAP::Parser::Result::Version
+
+TAP syntax version token.
+
+=item TAP::Parser::Result::YAML
+
+YAML result token.
+
+=item TAP::Parser::ResultFactory
+
+Factory for creating TAP::Parser output objects
+
+=item TAP::Parser::Scheduler
+
+Schedule tests during parallel testing
+
+=item TAP::Parser::Scheduler::Job
+
+A single testing job.
+
+=item TAP::Parser::Scheduler::Spinner
+
+A no-op job.
+
+=item TAP::Parser::Source
+
+Stream output from some source
+
+=item TAP::Parser::Source::Perl
+
+Stream Perl output
+
+=item TAP::Parser::Utils
+
+Internal TAP::Parser utilities
+
+=item TAP::Parser::YAMLish::Reader
+
+Read YAMLish data from iterator
+
+=item TAP::Parser::YAMLish::Writer
+
+Write YAMLish data
+
+=item Term::ANSIColor
+
+Color screen output using ANSI escape sequences
+
+=item Term::Cap
+
+Perl termcap interface
+
+=item Term::Complete
+
+Perl word completion module
+
+=item Term::ReadLine
+
+Perl interface to various C<readline> packages.
+
+=item Term::UI
+
+Term::ReadLine UI made easy
+
+=item Test
+
+Provides a simple framework for writing test scripts
+
+=item Test::Builder
+
+Backend for building test libraries
+
+=item Test::Builder::Module
+
+Base class for test modules
+
+=item Test::Builder::Tester
+
+Test testsuites that have been built with
+
+=item Test::Builder::Tester::Color
+
+Turn on colour in Test::Builder::Tester
+
+=item Test::Harness
+
+Run Perl standard test scripts with statistics
+
+=item Test::More
+
+Yet another framework for writing test scripts
+
+=item Test::Simple
+
+Basic utilities for writing tests.
+
+=item Test::Tutorial
+
+A tutorial about writing really basic tests
+
+=item Text::Abbrev
+
+Create an abbreviation table from a list
+
+=item Text::Balanced
+
+Extract delimited text sequences from strings.
+
+=item Text::ParseWords
+
+Parse text into an array of tokens or array of arrays
+
+=item Text::Soundex
+
+Implementation of the soundex algorithm.
+
+=item Text::Tabs
+
+Expand and unexpand tabs per the unix expand(1) and unexpand(1)
+
+=item Text::Wrap
+
+Line wrapping to form simple paragraphs
+
+=item Thread
+
+Manipulate threads in Perl (for old code only)
+
+=item Thread::Queue
+
+Thread-safe queues
+
+=item Thread::Semaphore
+
+Thread-safe semaphores
+
+=item Tie::Array
+
+Base class for tied arrays
+
+=item Tie::File
+
+Access the lines of a disk file via a Perl array
+
+=item Tie::Handle
+
+Base class definitions for tied handles
+
+=item Tie::Hash
+
+Base class definitions for tied hashes
+
+=item Tie::Hash::NamedCapture
+
+Named regexp capture buffers
+
+=item Tie::Memoize
+
+Add data to hash when needed
+
+=item Tie::RefHash
+
+Use references as hash keys
+
+=item Tie::Scalar
+
+Base class definitions for tied scalars
+
+=item Tie::StdHandle
+
+Base class definitions for tied handles
+
+=item Tie::SubstrHash
+
+Fixed-table-size, fixed-key-length hashing
+
+=item Time::HiRes
+
+High resolution alarm, sleep, gettimeofday, interval timers
+
+=item Time::Local
+
+Efficiently compute time from local and GMT time
+
+=item Time::Piece
+
+Object Oriented time objects
+
+=item Time::Seconds
+
+A simple API to convert seconds to other date values
+
+=item Time::gmtime
+
+By-name interface to Perl's built-in gmtime() function
+
+=item Time::localtime
+
+By-name interface to Perl's built-in localtime() function
+
+=item Time::tm
+
+Internal object used by Time::gmtime and Time::localtime
+
+=item UNIVERSAL
+
+Base class for ALL classes (blessed references)
+
+=item Unicode::Collate
+
+Unicode Collation Algorithm
+
+=item Unicode::Normalize
+
+Unicode Normalization Forms
+
+=item Unicode::UCD
+
+Unicode character database
+
+=item User::grent
+
+By-name interface to Perl's built-in getgr*() functions
+
+=item User::pwent
+
+By-name interface to Perl's built-in getpw*() functions
+
+=item VMS::DCLsym
+
+Perl extension to manipulate DCL symbols
+
+=item VMS::Stdio
+
+Standard I/O functions via VMS extensions
+
+=item Win32
+
+Interfaces to some Win32 API Functions
+
+=item Win32API::File
+
+Low-level access to Win32 system API calls for files/dirs.
+
+=item Win32CORE
+
+Win32 CORE function stubs
+
+=item XS::APItest
+
+Test the perl C API
+
+=item XS::APItest::KeywordRPN
+
+Write arithmetic expressions in RPN
+
+=item XS::Typemap
+
+Module to test the XS typemaps distributed with perl
+
+=item XSLoader
+
+Dynamically load C libraries into Perl code
+
+=item version::Internals
+
+Perl extension for Version Objects
+
+=back
+
+To find out I<all> modules installed on your system, including
+those without documentation or outside the standard release,
+just use the following command (under the default win32 shell,
+double quotes should be used instead of single quotes).
+
+ % perl -MFile::Find=find -MFile::Spec::Functions -Tlwe \
+ 'find { wanted => sub { print canonpath $_ if /\.pm\z/ },
+ no_chdir => 1 }, @INC'
+
+(The -T is here to prevent '.' from being listed in @INC.)
+They should all have their own documentation installed and accessible
+via your system man(1) command. If you do not have a B<find>
+program, you can use the Perl B<find2perl> program instead, which
+generates Perl code as output you can run through perl. If you
+have a B<man> program but it doesn't find your modules, you'll have
+to fix your manpath. See L<perl> for details. If you have no
+system B<man> command, you might try the B<perldoc> program.
+
+Note also that the command C<perldoc perllocal> gives you a (possibly
+incomplete) list of the modules that have been further installed on
+your system. (The perllocal.pod file is updated by the standard MakeMaker
+install process.)
+
+=head2 Extension Modules
+
+Extension modules are written in C (or a mix of Perl and C). They
+are usually dynamically loaded into Perl if and when you need them,
+but may also be linked in statically. Supported extension modules
+include Socket, Fcntl, and POSIX.
+
+Many popular C extension modules do not come bundled (at least, not
+completely) due to their sizes, volatility, or simply lack of time
+for adequate testing and configuration across the multitude of
+platforms on which Perl was beta-tested. You are encouraged to
+look for them on CPAN (described below), or using web search engines
+like Alta Vista or Google.
+
+=head1 CPAN
+
+CPAN stands for Comprehensive Perl Archive Network; it's a globally
+replicated trove of Perl materials, including documentation, style
+guides, tricks and traps, alternate ports to non-Unix systems and
+occasional binary distributions for these. Search engines for
+CPAN can be found at http://www.cpan.org/
+
+Most importantly, CPAN includes around a thousand unbundled modules,
+some of which require a C compiler to build. Major categories of
+modules are:
+
+=over
+
+=item *
+
+Language Extensions and Documentation Tools
+
+=item *
+
+Development Support
+
+=item *
+
+Operating System Interfaces
+
+=item *
+
+Networking, Device Control (modems) and InterProcess Communication
+
+=item *
+
+Data Types and Data Type Utilities
+
+=item *
+
+Database Interfaces
+
+=item *
+
+User Interfaces
+
+=item *
+
+Interfaces to / Emulations of Other Programming Languages
+
+=item *
+
+File Names, File Systems and File Locking (see also File Handles)
+
+=item *
+
+String Processing, Language Text Processing, Parsing, and Searching
+
+=item *
+
+Option, Argument, Parameter, and Configuration File Processing
+
+=item *
+
+Internationalization and Locale
+
+=item *
+
+Authentication, Security, and Encryption
+
+=item *
+
+World Wide Web, HTML, HTTP, CGI, MIME
+
+=item *
+
+Server and Daemon Utilities
+
+=item *
+
+Archiving and Compression
+
+=item *
+
+Images, Pixmap and Bitmap Manipulation, Drawing, and Graphing
+
+=item *
+
+Mail and Usenet News
+
+=item *
+
+Control Flow Utilities (callbacks and exceptions etc)
+
+=item *
+
+File Handle and Input/Output Stream Utilities
+
+=item *
+
+Miscellaneous Modules
+
+=back
+
+The list of the registered CPAN sites follows.
+Please note that the sorting order is alphabetical on fields:
+
+Continent
+ |
+ |-->Country
+ |
+ |-->[state/province]
+ |
+ |-->ftp
+ |
+ |-->[http]
+
+and thus the North American servers happen to be listed between the
+European and the South American sites.
+
+Registered CPAN sites
+
+=head2 Africa
+
+=over 4
+
+=item South Africa
+
+ http://cpan.mirror.ac.za/
+ ftp://cpan.mirror.ac.za/
+ http://mirror.is.co.za/pub/cpan/
+ ftp://ftp.is.co.za/pub/cpan/
+ ftp://ftp.saix.net/pub/CPAN/
+
+=back
+
+=head2 Asia
+
+=over 4
+
+=item Hong Kong
+
+ http://ftp.cuhk.edu.hk/pub/packages/perl/CPAN/
+ ftp://ftp.cuhk.edu.hk/pub/packages/perl/CPAN/
+ http://mirrors.geoexpat.com/cpan/
+
+=item India
+
+ http://perlmirror.indialinks.com/
+
+=item Indonesia
+
+ http://cpan.biz.net.id/
+ http://komo.vlsm.org/CPAN/
+ ftp://komo.vlsm.org/CPAN/
+ http://cpan.pesat.net.id/
+ http://mirror.unej.ac.id/cpan/
+ ftp://mirror.unej.ac.id/cpan/
+
+=item Japan
+
+ ftp://ftp.u-aizu.ac.jp/pub/CPAN
+ ftp://ftp.kddilabs.jp/CPAN/
+ http://ftp.nara.wide.ad.jp/pub/CPAN/
+ ftp://ftp.nara.wide.ad.jp/pub/CPAN/
+ http://ftp.jaist.ac.jp/pub/CPAN/
+ ftp://ftp.jaist.ac.jp/pub/CPAN/
+ ftp://ftp.dti.ad.jp/pub/lang/CPAN/
+ ftp://ftp.ring.gr.jp/pub/lang/perl/CPAN/
+ http://ftp.riken.jp/lang/CPAN/
+ ftp://ftp.riken.jp/lang/CPAN/
+ http://ftp.yz.yamagata-u.ac.jp/pub/lang/cpan/
+ ftp://ftp.yz.yamagata-u.ac.jp/pub/lang/cpan/
+
+=item Kazakhstan
+
+ http://mirror.linuxiso.kz/CPAN/
+
+=item Republic of Korea
+
+ http://ftp.kaist.ac.kr/pub/CPAN
+ ftp://ftp.kaist.ac.kr/pub/CPAN
+ http://cpan.mirror.cdnetworks.com/
+ ftp://cpan.mirror.cdnetworks.com/CPAN/
+ http://cpan.sarang.net/
+ ftp://cpan.sarang.net/CPAN/
+
+=item Russia
+
+ http://cpan.tomsk.ru/
+ ftp://cpan.tomsk.ru/
+
+=item Singapore
+
+ http://mirror.averse.net/pub/CPAN
+ ftp://mirror.averse.net/pub/CPAN
+ http://cpan.mirror.choon.net/
+ http://cpan.oss.eznetsols.org
+ ftp://ftp.oss.eznetsols.org/cpan
+
+=item Taiwan
+
+ http://ftp.cse.yzu.edu.tw/pub/CPAN/
+ ftp://ftp.cse.yzu.edu.tw/pub/CPAN/
+ http://cpan.nctu.edu.tw/
+ ftp://cpan.nctu.edu.tw/
+ ftp://ftp.ncu.edu.tw/CPAN/
+ http://cpan.cdpa.nsysu.edu.tw/
+ ftp://cpan.cdpa.nsysu.edu.tw/Unix/Lang/CPAN/
+ http://cpan.stu.edu.tw
+ ftp://ftp.stu.edu.tw/CPAN
+ http://ftp.stu.edu.tw/CPAN
+ ftp://ftp.stu.edu.tw/pub/CPAN
+ http://cpan.cs.pu.edu.tw/
+ ftp://cpan.cs.pu.edu.tw/pub/CPAN
+
+=item Thailand
+
+ http://mirrors.issp.co.th/cpan/
+ ftp://mirrors.issp.co.th/cpan/
+
+=item Turkey
+
+ http://cpan.gazi.edu.tr/
+ http://cpan.ulak.net.tr
+ ftp://ftp.ulak.net.tr/pub/CPAN
+
+=item Viet Nam
+
+ http://mirror-fpt-telecom.fpt.net/cpan/
+ ftp://mirror-fpt-telecom.fpt.net/cpan/
+
+=back
+
+=head2 Central America
+
+=over 4
+
+=item Costa Rica
+
+ http://mirrors.ucr.ac.cr/CPAN/
+ ftp://mirrors.ucr.ac.cr/CPAN/
+
+=back
+
+=head2 Europe
+
+=over 4
+
+=item Austria
+
+ http://cpan.inode.at/
+ ftp://cpan.inode.at
+ http://gd.tuwien.ac.at/languages/perl/CPAN/
+ ftp://gd.tuwien.ac.at/pub/CPAN/
+
+=item Belgium
+
+ http://ftp.belnet.be/mirror/ftp.cpan.org/
+ ftp://ftp.belnet.be/mirror/ftp.cpan.org/
+ http://ftp.easynet.be/pub/CPAN/
+ http://cpan.weepee.org/
+ http://cpan.fluoline.net/
+
+=item Bosnia and Herzegovina
+
+ http://cpan.blic.net/
+
+=item Bulgaria
+
+ http://cpan.cbox.biz/
+ ftp://cpan.cbox.biz/cpan/
+ http://cpan.digsys.bg/
+ ftp://ftp.digsys.bg/pub/CPAN
+
+=item Croatia
+
+ http://ftp.carnet.hr/pub/CPAN/
+ ftp://ftp.carnet.hr/pub/CPAN/
+
+=item Czech Republic
+
+ ftp://ftp.fi.muni.cz/pub/CPAN/
+ http://archive.cpan.cz/
+
+=item Denmark
+
+ http://mirrors.dotsrc.org/cpan
+ ftp://mirrors.dotsrc.org/cpan/
+ http://www.cpan.dk/
+ http://mirror.uni-c.dk/pub/CPAN/
+
+=item Finland
+
+ ftp://ftp.funet.fi/pub/languages/perl/CPAN/
+ http://mirror.eunet.fi/CPAN
+
+=item France
+
+ http://cpan.enstimac.fr/
+ ftp://ftp.inria.fr/pub/CPAN/
+ http://distrib-coffee.ipsl.jussieu.fr/pub/mirrors/cpan/
+ ftp://distrib-coffee.ipsl.jussieu.fr/pub/mirrors/cpan/
+ ftp://ftp.lip6.fr/pub/perl/CPAN/
+ http://mir2.ovh.net/ftp.cpan.org
+ ftp://mir1.ovh.net/ftp.cpan.org
+ http://cpan.miroir-francais.fr/
+ ftp://miroir-francais.fr/pub/cpan/
+ ftp://ftp.oleane.net/pub/CPAN/
+ http://ftp.crihan.fr/mirrors/ftp.cpan.org/
+ ftp://ftp.crihan.fr/mirrors/ftp.cpan.org/
+ http://ftp.u-strasbg.fr/CPAN
+ ftp://ftp.u-strasbg.fr/CPAN
+ http://cpan.cict.fr/
+ ftp://cpan.cict.fr/pub/CPAN/
+
+=item Germany
+
+ ftp://ftp.fu-berlin.de/unix/languages/perl/
+ http://mirrors.softliste.de/cpan/
+ ftp://ftp.rub.de/pub/CPAN/
+ http://www.planet-elektronik.de/CPAN/
+ http://ftp.hosteurope.de/pub/CPAN/
+ ftp://ftp.hosteurope.de/pub/CPAN/
+ http://www.mirrorspace.org/cpan/
+ http://mirror.netcologne.de/cpan/
+ ftp://mirror.netcologne.de/cpan/
+ ftp://ftp.freenet.de/pub/ftp.cpan.org/pub/CPAN/
+ http://ftp-stud.hs-esslingen.de/pub/Mirrors/CPAN/
+ ftp://ftp-stud.hs-esslingen.de/pub/Mirrors/CPAN/
+ http://mirrors.zerg.biz/cpan/
+ http://ftp.gwdg.de/pub/languages/perl/CPAN/
+ ftp://ftp.gwdg.de/pub/languages/perl/CPAN/
+ http://dl.ambiweb.de/mirrors/ftp.cpan.org/
+ http://cpan.mirror.clusters.kg/
+ http://cpan.mirror.iphh.net/
+ ftp://cpan.mirror.iphh.net/pub/CPAN/
+ http://cpan.mirroring.de/
+ http://mirror.informatik.uni-mannheim.de/pub/mirrors/CPAN/
+ ftp://mirror.informatik.uni-mannheim.de/pub/mirrors/CPAN/
+ http://ftp.cw.net/pub/CPAN/
+ ftp://ftp.cw.net/pub/CPAN/
+ http://cpan.cpantesters.org/
+ ftp://cpan.cpantesters.org/CPAN/
+ http://cpan.mirrored.de/
+ ftp://mirror.petamem.com/CPAN/
+ http://cpan.noris.de/
+ ftp://cpan.noris.de/pub/CPAN/
+ ftp://ftp.mpi-sb.mpg.de/pub/perl/CPAN/
+ ftp://ftp.gmd.de/mirrors/CPAN/
+
+=item Greece
+
+ ftp://ftp.forthnet.gr/pub/languages/perl/CPAN
+ ftp://ftp.ntua.gr/pub/lang/perl/
+ http://cpan.cc.uoc.gr/
+ ftp://ftp.cc.uoc.gr/mirrors/CPAN/
+
+=item Hungary
+
+ http://cpan.mirrors.enexis.hu/
+ ftp://cpan.mirrors.enexis.hu/mirrors/cpan/
+ http://cpan.hu/
+
+=item Iceland
+
+ http://ftp.rhnet.is/pub/CPAN/
+ ftp://ftp.rhnet.is/pub/CPAN/
+
+=item Ireland
+
+ http://ftp.esat.net/pub/languages/perl/CPAN/
+ ftp://ftp.esat.net/pub/languages/perl/CPAN/
+ http://ftp.heanet.ie/mirrors/ftp.perl.org/pub/CPAN
+ ftp://ftp.heanet.ie/mirrors/ftp.perl.org/pub/CPAN
+
+=item Italy
+
+ http://bo.mirror.garr.it/mirrors/CPAN/
+ http://cpan.panu.it/
+ ftp://ftp.panu.it/pub/mirrors/perl/CPAN/
+ http://cpan.fastbull.org/
+
+=item Latvia
+
+ http://kvin.lv/pub/CPAN/
+
+=item Lithuania
+
+ http://ftp.litnet.lt/pub/CPAN/
+ ftp://ftp.litnet.lt/pub/CPAN/
+
+=item Malta
+
+ http://cpan.waldonet.net.mt/
+
+=item Netherlands
+
+ ftp://ftp.quicknet.nl/pub/CPAN/
+ http://mirror.hostfuss.com/CPAN/
+ ftp://mirror.hostfuss.com/CPAN/
+ http://mirrors3.kernel.org/cpan/
+ ftp://mirrors3.kernel.org/pub/CPAN/
+ http://cpan.osmirror.nl/
+ ftp://ftp.osmirror.nl/pub/cpan/
+ http://cpan.mirror.versatel.nl/
+ ftp://ftp.mirror.versatel.nl/cpan/
+ ftp://download.xs4all.nl/pub/mirror/CPAN/
+ http://mirror.leaseweb.com/CPAN/
+ ftp://mirror.leaseweb.com/CPAN/
+ ftp://ftp.cpan.nl/pub/CPAN/
+ http://archive.cs.uu.nl/mirror/CPAN/
+ ftp://ftp.cs.uu.nl/mirror/CPAN/
+ http://https://luxitude.net/cpan/
+
+=item Norway
+
+ ftp://ftp.uninett.no/pub/languages/perl/CPAN
+ ftp://ftp.uit.no/pub/languages/perl/cpan/
+
+=item Poland
+
+ http://mirror.icis.pcz.pl/CPAN/
+ ftp://mirror.icis.pcz.pl/CPAN/
+ http://piotrkosoft.net/pub/mirrors/CPAN/
+ ftp://ftp.piotrkosoft.net/pub/mirrors/CPAN/
+ http://ftp.man.poznan.pl/pub/CPAN
+ ftp://ftp.man.poznan.pl/pub/CPAN
+ ftp://sunsite.icm.edu.pl/pub/CPAN/
+ ftp://ftp.tpnet.pl/d4/CPAN/
+
+=item Portugal
+
+ http://cpan.dei.uc.pt/
+ ftp://ftp.dei.uc.pt/pub/CPAN
+ ftp://ftp.ist.utl.pt/pub/CPAN/
+ http://cpan.perl.pt/
+ http://cpan.ip.pt/
+ ftp://cpan.ip.pt/pub/cpan/
+ http://mirrors.nfsi.pt/CPAN/
+ ftp://mirrors.nfsi.pt/pub/CPAN/
+ http://cpan.dcc.fc.up.pt/
+
+=item Romania
+
+ http://ftp.astral.ro/pub/CPAN/
+ ftp://ftp.astral.ro/pub/CPAN/
+ ftp://ftp.lug.ro/CPAN
+ http://mirrors.xservers.ro/CPAN/
+ http://mirrors.hostingromania.ro/ftp.cpan.org/
+ ftp://ftp.hostingromania.ro/mirrors/ftp.cpan.org/
+ ftp://ftp.iasi.roedu.net/pub/mirrors/ftp.cpan.org/
+ ftp://ftp.ambra.ro/pub/CPAN
+
+=item Russia
+
+ ftp://ftp.aha.ru/CPAN/
+ http://cpan.rinet.ru/
+ ftp://cpan.rinet.ru/pub/mirror/CPAN/
+ ftp://ftp.SpringDaemons.com/pub/CPAN/
+ http://cpan.nx1.ru/
+ ftp://cpan.nx1.ru/
+ http://mirror.rol.ru/CPAN/
+ http://ftp.silvernet.ru/CPAN/
+ http://ftp.spbu.ru/CPAN/
+ ftp://ftp.spbu.ru/CPAN/
+
+=item Slovakia
+
+ http://cpan.fyxm.net/
+
+=item Slovenia
+
+ http://www.klevze.si/cpan
+
+=item Spain
+
+ http://osl.ugr.es/CPAN/
+ ftp://ftp.rediris.es/mirror/CPAN/
+ http://ftp.gui.uva.es/sites/cpan.org/
+ ftp://ftp.gui.uva.es/sites/cpan.org/
+
+=item Sweden
+
+ http://mirrors4.kernel.org/cpan/
+ ftp://mirrors4.kernel.org/pub/CPAN/
+
+=item Switzerland
+
+ http://cpan.mirror.solnet.ch/
+ ftp://ftp.solnet.ch/mirror/CPAN/
+ http://mirror.switch.ch/ftp/mirror/CPAN/
+ ftp://mirror.switch.ch/mirror/CPAN/
+
+=item Ukraine
+
+ http://cpan.makeperl.org/
+ ftp://cpan.makeperl.org/pub/CPAN
+ http://cpan.org.ua/
+ http://no-more.kiev.ua/CPAN/
+ ftp://no-more.kiev.ua/pub/CPAN/
+ http://cpan.gafol.net/
+ ftp://ftp.gafol.net/pub/cpan/
+
+=item United Kingdom
+
+ http://www.mirrorservice.org/sites/ftp.funet.fi/pub/languages/perl/CPAN/
+ ftp://ftp.mirrorservice.org/sites/ftp.funet.fi/pub/languages/perl/CPAN/
+ http://mirror.tje.me.uk/pub/mirrors/ftp.cpan.org/
+ ftp://mirror.tje.me.uk/pub/mirrors/ftp.cpan.org/
+ http://www.mirror.8086.net/sites/CPAN/
+ ftp://ftp.mirror.8086.net/sites/CPAN/
+ http://cpan.mirror.anlx.net/
+ ftp://ftp.mirror.anlx.net/CPAN/
+ http://mirror.bytemark.co.uk/CPAN/
+ ftp://mirror.bytemark.co.uk/CPAN/
+ http://cpan.etla.org/
+ ftp://cpan.etla.org/pub/CPAN
+ ftp://ftp.demon.co.uk/pub/CPAN/
+ http://mirror.sov.uk.goscomb.net/CPAN/
+ ftp://mirror.sov.uk.goscomb.net/pub/CPAN/
+ http://ftp.plig.net/pub/CPAN/
+ ftp://ftp.plig.net/pub/CPAN/
+ http://ftp.ticklers.org/pub/CPAN/
+ ftp://ftp.ticklers.org/pub/CPAN/
+ http://cpan.mirrors.uk2.net/
+ ftp://mirrors.uk2.net/pub/CPAN/
+ http://mirror.ox.ac.uk/sites/www.cpan.org/
+ ftp://mirror.ox.ac.uk/sites/www.cpan.org/
+
+=back
+
+=head2 North America
+
+=over 4
+
+=item Bahamas
+
+ http://www.securehost.com/mirror/CPAN/
+
+=item Canada
+
+ http://cpan.justanotherperlhacker.com/pub/CPAN/
+ ftp://cpan.justanotherperlhacker.com/pub/CPAN/
+ http://cpan.arcticnetwork.ca
+ ftp://mirror.arcticnetwork.ca/pub/CPAN
+ http://cpan.sunsite.ualberta.ca/
+ ftp://cpan.sunsite.ualberta.ca/pub/CPAN/
+ http://theoryx5.uwinnipeg.ca/pub/CPAN/
+ ftp://theoryx5.uwinnipeg.ca/pub/CPAN/
+ http://arwen.cs.dal.ca/mirror/CPAN/
+ ftp://arwen.cs.dal.ca/pub/mirror/CPAN/
+ http://CPAN.mirror.rafal.ca/
+ ftp://CPAN.mirror.rafal.ca/pub/CPAN/
+ ftp://ftp.nrc.ca/pub/CPAN/
+ http://mirror.csclub.uwaterloo.ca/pub/CPAN/
+ ftp://mirror.csclub.uwaterloo.ca/pub/CPAN/
+
+=item Mexico
+
+ http://www.msg.com.mx/CPAN/
+ ftp://ftp.msg.com.mx/pub/CPAN/
+
+=item United States
+
+=over 8
+
+=item Alabama
+
+ http://mirror.hiwaay.net/CPAN/
+ ftp://mirror.hiwaay.net/CPAN/
+
+=item California
+
+ http://cpan.knowledgematters.net/
+ http://cpan.binkerton.com/
+ http://cpan.develooper.com/
+ http://mirrors.gossamer-threads.com/CPAN
+ http://cpan.schatt.com/
+ http://mirrors.kernel.org/cpan/
+ ftp://mirrors.kernel.org/pub/CPAN
+ http://mirrors2.kernel.org/cpan/
+ ftp://mirrors2.kernel.org/pub/CPAN/
+ http://cpan.mirrors.redwire.net/
+ http://cpan.mirror.facebook.net/
+ http://mirrors1.kernel.org/cpan/
+ ftp://mirrors1.kernel.org/pub/CPAN/
+ http://cpan-sj.viaverio.com/
+ ftp://cpan-sj.viaverio.com/pub/CPAN/
+ http://www.perl.com/CPAN/
+ http://cpan.yahoo.com/
+
+=item Florida
+
+ ftp://ftp.cise.ufl.edu/pub/mirrors/CPAN/
+ http://mirror.atlantic.net/pub/CPAN/
+ ftp://mirror.atlantic.net/pub/CPAN/
+ http://mirror.candidhosting.com/pub/CPAN
+ ftp://mirror.candidhosting.com/pub/CPAN
+
+=item Idaho
+
+ http://mirror.its.uidaho.edu/pub/cpan/
+ ftp://mirror.its.uidaho.edu/cpan/
+
+=item Illinois
+
+ http://cpan.mirrors.hoobly.com/
+ http://cpan.uchicago.edu/pub/CPAN/
+ ftp://cpan.uchicago.edu/pub/CPAN/
+ http://mirrors.servercentral.net/CPAN/
+ http://www.stathy.com/CPAN/
+ ftp://www.stathy.com/CPAN/
+
+=item Indiana
+
+ ftp://ftp.uwsg.iu.edu/pub/perl/CPAN/
+ http://cpan.netnitco.net/
+ ftp://cpan.netnitco.net/pub/mirrors/CPAN/
+ http://ftp.ndlug.nd.edu/pub/perl/
+ ftp://ftp.ndlug.nd.edu/pub/perl/
+ http://fx.saintjoe.edu/pub/CPAN
+
+=item Massachusetts
+
+ ftp://ftp.ccs.neu.edu/net/mirrors/ftp.funet.fi/pub/languages/perl/CPAN/
+
+=item Michigan
+
+ http://ftp.wayne.edu/cpan/
+ ftp://ftp.wayne.edu/cpan/
+
+=item Minnesota
+
+ http://cpan.msi.umn.edu/
+
+=item New Jersey
+
+ http://mirror.datapipe.net/CPAN/
+ ftp://mirror.datapipe.net/pub/CPAN/
+
+=item New York
+
+ http://mirrors.24-7-solutions.net/pub/CPAN/
+ ftp://mirrors.24-7-solutions.net/pub/CPAN/
+ http://mirror.cc.columbia.edu/pub/software/cpan/
+ ftp://mirror.cc.columbia.edu/pub/software/cpan/
+ http://cpan.belfry.net/
+ http://cpan.erlbaum.net/
+ ftp://cpan.erlbaum.net/CPAN/
+ http://cpan.hexten.net/
+ ftp://cpan.hexten.net/
+ http://ftp.fxcorporate.com/CPAN/
+ ftp://ftp.fxcorporate.com/pub/CPAN/
+ ftp://mirror.nyi.net/CPAN/
+ http://mirror.rit.edu/CPAN/
+ ftp://mirror.rit.edu/CPAN/
+
+=item North Carolina
+
+ http://www.ibiblio.org/pub/mirrors/CPAN
+ ftp://ftp.ncsu.edu/pub/mirror/CPAN/
+
+=item Oregon
+
+ http://ftp.osuosl.org/pub/CPAN/
+ ftp://ftp.osuosl.org/pub/CPAN/
+
+=item Pennsylvania
+
+ http://ftp.epix.net/CPAN/
+ ftp://ftp.epix.net/pub/languages/perl/
+ http://cpan.pair.com/
+ ftp://cpan.pair.com/pub/CPAN/
+
+=item South Carolina
+
+ http://cpan.mirror.clemson.edu/
+
+=item Tennessee
+
+ http://mira.sunsite.utk.edu/CPAN/
+
+=item Texas
+
+ http://mirror.uta.edu/CPAN
+
+=item Utah
+
+ http://cpan.cs.utah.edu
+ ftp://cpan.cs.utah.edu/pub/CPAN/
+ ftp://mirror.xmission.com/CPAN/
+
+=item Virginia
+
+ http://cpan-du.viaverio.com/
+ ftp://cpan-du.viaverio.com/pub/CPAN/
+ http://perl.secsup.org/
+ ftp://perl.secsup.org/pub/perl/
+ ftp://mirror.cogentco.com/pub/CPAN/
+
+=item Washington
+
+ http://cpan.llarian.net/
+ ftp://cpan.llarian.net/pub/CPAN/
+ ftp://ftp-mirror.internap.com/pub/CPAN/
+
+=item Wisconsin
+
+ http://cpan.mirrors.tds.net
+ ftp://cpan.mirrors.tds.net/pub/CPAN
+ http://mirror.sit.wisc.edu/pub/CPAN/
+ ftp://mirror.sit.wisc.edu/pub/CPAN/
+
+=back
+
+=back
+
+=head2 Oceania
+
+=over 4
+
+=item Australia
+
+ http://mirror.internode.on.net/pub/cpan/
+ ftp://mirror.internode.on.net/pub/cpan/
+ http://cpan.mirror.aussiehq.net.au/
+ http://mirror.as24220.net/cpan/
+ ftp://mirror.as24220.net/cpan/
+
+=item New Zealand
+
+ ftp://ftp.auckland.ac.nz/pub/perl/CPAN/
+ http://cpan.inspire.net.nz
+ ftp://cpan.inspire.net.nz/cpan
+ http://cpan.catalyst.net.nz/CPAN/
+ ftp://cpan.catalyst.net.nz/pub/CPAN/
+
+=back
+
+=head2 South America
+
+=over 4
+
+=item Argentina
+
+ http://cpan.patan.com.ar/
+ http://cpan.localhost.net.ar
+ ftp://mirrors.localhost.net.ar/pub/mirrors/CPAN
+
+=item Brazil
+
+ ftp://cpan.pop-mg.com.br/pub/CPAN/
+ http://ftp.pucpr.br/CPAN
+ ftp://ftp.pucpr.br/CPAN
+ http://cpan.kinghost.net/
+ ftp://ftp.linorg.usp.br/CPAN
+
+=item Chile
+
+ http://cpan.dcc.uchile.cl/
+ ftp://cpan.dcc.uchile.cl/pub/lang/cpan/
+
+=item Colombia
+
+ http://www.laqee.unal.edu.co/CPAN/
+
+=back
+
+=head2 RSYNC Mirrors
+
+ mirror.as24220.net::cpan
+ cpan.inode.at::CPAN
+ gd.tuwien.ac.at::CPAN
+ ftp.belnet.be::packages/cpan
+ rsync.linorg.usp.br::CPAN
+ rsync.arcticnetwork.ca::CPAN
+ CPAN.mirror.rafal.ca::CPAN
+ mirror.csclub.uwaterloo.ca::CPAN
+ theoryx5.uwinnipeg.ca::CPAN
+ www.laqee.unal.edu.co::CPAN
+ mirror.uni-c.dk::CPAN
+ rsync.nic.funet.fi::CPAN
+ rsync://distrib-coffee.ipsl.jussieu.fr/pub/mirrors/cpan/
+ mir1.ovh.net::CPAN
+ miroir-francais.fr::cpan
+ ftp.crihan.fr::CPAN
+ rsync://mirror.cict.fr/cpan/
+ rsync://mirror.netcologne.de/cpan/
+ ftp-stud.hs-esslingen.de::CPAN/
+ ftp.gwdg.de::FTP/languages/perl/CPAN/
+ cpan.mirror.iphh.net::CPAN
+ cpan.cpantesters.org::cpan
+ cpan.hu::CPAN
+ komo.vlsm.org::CPAN
+ mirror.unej.ac.id::cpan
+ ftp.esat.net::/pub/languages/perl/CPAN
+ ftp.heanet.ie::mirrors/ftp.perl.org/pub/CPAN
+ rsync.panu.it::CPAN
+ cpan.fastbull.org::CPAN
+ ftp.kddilabs.jp::cpan
+ ftp.nara.wide.ad.jp::cpan/
+ rsync://ftp.jaist.ac.jp/pub/CPAN/
+ rsync://ftp.riken.jp/cpan/
+ mirror.linuxiso.kz::CPAN
+ rsync://mirrors3.kernel.org/mirrors/CPAN/
+ rsync://rsync.osmirror.nl/cpan/
+ mirror.leaseweb.com::CPAN
+ cpan.nautile.nc::CPAN
+ mirror.icis.pcz.pl::CPAN
+ piotrkosoft.net::mirrors/CPAN
+ rsync://cpan.perl.pt/
+ ftp.kaist.ac.kr::cpan
+ cpan.sarang.net::CPAN
+ mirror.averse.net::cpan
+ rsync.oss.eznetsols.org
+ mirror.ac.za::cpan
+ ftp.is.co.za::IS-Mirror/ftp.cpan.org/
+ rsync://ftp.gui.uva.es/cpan/
+ rsync://mirrors4.kernel.org/mirrors/CPAN/
+ ftp.solnet.ch::CPAN
+ ftp.ulak.net.tr::CPAN
+ gafol.net::cpan
+ rsync.mirrorservice.org::ftp.funet.fi/pub/
+ rsync://rsync.mirror.8086.net/CPAN/
+ rsync.mirror.anlx.net::CPAN
+ mirror.bytemark.co.uk::CPAN
+ ftp.plig.net::CPAN
+ rsync://ftp.ticklers.org:CPAN/
+ mirrors.ibiblio.org::CPAN
+ cpan-du.viaverio.com::CPAN
+ mirror.hiwaay.net::CPAN
+ rsync://mira.sunsite.utk.edu/CPAN/
+ cpan.mirrors.tds.net::CPAN
+ mirror.its.uidaho.edu::cpan
+ rsync://mirror.cc.columbia.edu::cpan/
+ ftp.fxcorporate.com::CPAN
+ rsync.atlantic.net::CPAN
+ mirrors.kernel.org::mirrors/CPAN
+ rsync://mirrors2.kernel.org/mirrors/CPAN/
+ cpan.pair.com::CPAN
+ rsync://mirror.rit.edu/CPAN/
+ rsync://mirror.facebook.net/cpan/
+ rsync://mirrors1.kernel.org/mirrors/CPAN/
+ cpan-sj.viaverio.com::CPAN
+
+For an up-to-date listing of CPAN sites,
+see http://www.cpan.org/SITES or ftp://www.cpan.org/SITES .
+
+=head1 Modules: Creation, Use, and Abuse
+
+(The following section is borrowed directly from Tim Bunce's modules
+file, available at your nearest CPAN site.)
+
+Perl implements a class using a package, but the presence of a
+package doesn't imply the presence of a class. A package is just a
+namespace. A class is a package that provides subroutines that can be
+used as methods. A method is just a subroutine that expects, as its
+first argument, either the name of a package (for "static" methods),
+or a reference to something (for "virtual" methods).
+
+A module is a file that (by convention) provides a class of the same
+name (sans the .pm), plus an import method in that class that can be
+called to fetch exported symbols. This module may implement some of
+its methods by loading dynamic C or C++ objects, but that should be
+totally transparent to the user of the module. Likewise, the module
+might set up an AUTOLOAD function to slurp in subroutine definitions on
+demand, but this is also transparent. Only the F<.pm> file is required to
+exist. See L<perlsub>, L<perltoot>, and L<AutoLoader> for details about
+the AUTOLOAD mechanism.
+
+=head2 Guidelines for Module Creation
+
+=over 4
+
+=item *
+
+Do similar modules already exist in some form?
+
+If so, please try to reuse the existing modules either in whole or
+by inheriting useful features into a new class. If this is not
+practical try to get together with the module authors to work on
+extending or enhancing the functionality of the existing modules.
+A perfect example is the plethora of packages in perl4 for dealing
+with command line options.
+
+If you are writing a module to expand an already existing set of
+modules, please coordinate with the author of the package. It
+helps if you follow the same naming scheme and module interaction
+scheme as the original author.
+
+=item *
+
+Try to design the new module to be easy to extend and reuse.
+
+Try to C<use warnings;> (or C<use warnings qw(...);>).
+Remember that you can add C<no warnings qw(...);> to individual blocks
+of code that need less warnings.
+
+Use blessed references. Use the two argument form of bless to bless
+into the class name given as the first parameter of the constructor,
+e.g.,:
+
+ sub new {
+ my $class = shift;
+ return bless {}, $class;
+ }
+
+or even this if you'd like it to be used as either a static
+or a virtual method.
+
+ sub new {
+ my $self = shift;
+ my $class = ref($self) || $self;
+ return bless {}, $class;
+ }
+
+Pass arrays as references so more parameters can be added later
+(it's also faster). Convert functions into methods where
+appropriate. Split large methods into smaller more flexible ones.
+Inherit methods from other modules if appropriate.
+
+Avoid class name tests like: C<die "Invalid" unless ref $ref eq 'FOO'>.
+Generally you can delete the C<eq 'FOO'> part with no harm at all.
+Let the objects look after themselves! Generally, avoid hard-wired
+class names as far as possible.
+
+Avoid C<< $r->Class::func() >> where using C<@ISA=qw(... Class ...)> and
+C<< $r->func() >> would work (see L<perlbot> for more details).
+
+Use autosplit so little used or newly added functions won't be a
+burden to programs that don't use them. Add test functions to
+the module after __END__ either using AutoSplit or by saying:
+
+ eval join('',<main::DATA>) || die $@ unless caller();
+
+Does your module pass the 'empty subclass' test? If you say
+C<@SUBCLASS::ISA = qw(YOURCLASS);> your applications should be able
+to use SUBCLASS in exactly the same way as YOURCLASS. For example,
+does your application still work if you change: C<< $obj = YOURCLASS->new(); >>
+into: C<< $obj = SUBCLASS->new(); >> ?
+
+Avoid keeping any state information in your packages. It makes it
+difficult for multiple other packages to use yours. Keep state
+information in objects.
+
+Always use B<-w>.
+
+Try to C<use strict;> (or C<use strict qw(...);>).
+Remember that you can add C<no strict qw(...);> to individual blocks
+of code that need less strictness.
+
+Always use B<-w>.
+
+Follow the guidelines in L<perlstyle>.
+
+Always use B<-w>.
+
+=item *
+
+Some simple style guidelines
+
+The perlstyle manual supplied with Perl has many helpful points.
+
+Coding style is a matter of personal taste. Many people evolve their
+style over several years as they learn what helps them write and
+maintain good code. Here's one set of assorted suggestions that
+seem to be widely used by experienced developers:
+
+Use underscores to separate words. It is generally easier to read
+$var_names_like_this than $VarNamesLikeThis, especially for
+non-native speakers of English. It's also a simple rule that works
+consistently with VAR_NAMES_LIKE_THIS.
+
+Package/Module names are an exception to this rule. Perl informally
+reserves lowercase module names for 'pragma' modules like integer
+and strict. Other modules normally begin with a capital letter and
+use mixed case with no underscores (need to be short and portable).
+
+You may find it helpful to use letter case to indicate the scope
+or nature of a variable. For example:
+
+ $ALL_CAPS_HERE constants only (beware clashes with Perl vars)
+ $Some_Caps_Here package-wide global/static
+ $no_caps_here function scope my() or local() variables
+
+Function and method names seem to work best as all lowercase.
+e.g., C<< $obj->as_string() >>.
+
+You can use a leading underscore to indicate that a variable or
+function should not be used outside the package that defined it.
+
+=item *
+
+Select what to export.
+
+Do NOT export method names!
+
+Do NOT export anything else by default without a good reason!
+
+Exports pollute the namespace of the module user. If you must
+export try to use @EXPORT_OK in preference to @EXPORT and avoid
+short or common names to reduce the risk of name clashes.
+
+Generally anything not exported is still accessible from outside the
+module using the ModuleName::item_name (or C<< $blessed_ref->method >>)
+syntax. By convention you can use a leading underscore on names to
+indicate informally that they are 'internal' and not for public use.
+
+(It is actually possible to get private functions by saying:
+C<my $subref = sub { ... }; &$subref;>. But there's no way to call that
+directly as a method, because a method must have a name in the symbol
+table.)
+
+As a general rule, if the module is trying to be object oriented
+then export nothing. If it's just a collection of functions then
+@EXPORT_OK anything but use @EXPORT with caution.
+
+=item *
+
+Select a name for the module.
+
+This name should be as descriptive, accurate, and complete as
+possible. Avoid any risk of ambiguity. Always try to use two or
+more whole words. Generally the name should reflect what is special
+about what the module does rather than how it does it. Please use
+nested module names to group informally or categorize a module.
+There should be a very good reason for a module not to have a nested name.
+Module names should begin with a capital letter.
+
+Having 57 modules all called Sort will not make life easy for anyone
+(though having 23 called Sort::Quick is only marginally better :-).
+Imagine someone trying to install your module alongside many others.
+If in any doubt ask for suggestions in comp.lang.perl.misc.
+
+If you are developing a suite of related modules/classes it's good
+practice to use nested classes with a common prefix as this will
+avoid namespace clashes. For example: Xyz::Control, Xyz::View,
+Xyz::Model etc. Use the modules in this list as a naming guide.
+
+If adding a new module to a set, follow the original author's
+standards for naming modules and the interface to methods in
+those modules.
+
+If developing modules for private internal or project specific use,
+that will never be released to the public, then you should ensure
+that their names will not clash with any future public module. You
+can do this either by using the reserved Local::* category or by
+using a category name that includes an underscore like Foo_Corp::*.
+
+To be portable each component of a module name should be limited to
+11 characters. If it might be used on MS-DOS then try to ensure each is
+unique in the first 8 characters. Nested modules make this easier.
+
+=item *
+
+Have you got it right?
+
+How do you know that you've made the right decisions? Have you
+picked an interface design that will cause problems later? Have
+you picked the most appropriate name? Do you have any questions?
+
+The best way to know for sure, and pick up many helpful suggestions,
+is to ask someone who knows. Comp.lang.perl.misc is read by just about
+all the people who develop modules and it's the best place to ask.
+
+All you need to do is post a short summary of the module, its
+purpose and interfaces. A few lines on each of the main methods is
+probably enough. (If you post the whole module it might be ignored
+by busy people - generally the very people you want to read it!)
+
+Don't worry about posting if you can't say when the module will be
+ready - just say so in the message. It might be worth inviting
+others to help you, they may be able to complete it for you!
+
+=item *
+
+README and other Additional Files.
+
+It's well known that software developers usually fully document the
+software they write. If, however, the world is in urgent need of
+your software and there is not enough time to write the full
+documentation please at least provide a README file containing:
+
+=over 10
+
+=item *
+
+A description of the module/package/extension etc.
+
+=item *
+
+A copyright notice - see below.
+
+=item *
+
+Prerequisites - what else you may need to have.
+
+=item *
+
+How to build it - possible changes to Makefile.PL etc.
+
+=item *
+
+How to install it.
+
+=item *
+
+Recent changes in this release, especially incompatibilities
+
+=item *
+
+Changes / enhancements you plan to make in the future.
+
+=back
+
+If the README file seems to be getting too large you may wish to
+split out some of the sections into separate files: INSTALL,
+Copying, ToDo etc.
+
+=over 4
+
+=item *
+
+Adding a Copyright Notice.
+
+How you choose to license your work is a personal decision.
+The general mechanism is to assert your Copyright and then make
+a declaration of how others may copy/use/modify your work.
+
+Perl, for example, is supplied with two types of licence: The GNU GPL
+and The Artistic Licence (see the files README, Copying, and Artistic,
+or L<perlgpl> and L<perlartistic>). Larry has good reasons for NOT
+just using the GNU GPL.
+
+My personal recommendation, out of respect for Larry, Perl, and the
+Perl community at large is to state something simply like:
+
+ Copyright (c) 1995 Your Name. All rights reserved.
+ This program is free software; you can redistribute it and/or
+ modify it under the same terms as Perl itself.
+
+This statement should at least appear in the README file. You may
+also wish to include it in a Copying file and your source files.
+Remember to include the other words in addition to the Copyright.
+
+=item *
+
+Give the module a version/issue/release number.
+
+To be fully compatible with the Exporter and MakeMaker modules you
+should store your module's version number in a non-my package
+variable called $VERSION. This should be a floating point
+number with at least two digits after the decimal (i.e., hundredths,
+e.g, C<$VERSION = "0.01">). Don't use a "1.3.2" style version.
+See L<Exporter> for details.
+
+It may be handy to add a function or method to retrieve the number.
+Use the number in announcements and archive file names when
+releasing the module (ModuleName-1.02.tar.Z).
+See perldoc ExtUtils::MakeMaker.pm for details.
+
+=item *
+
+How to release and distribute a module.
+
+It's good idea to post an announcement of the availability of your
+module (or the module itself if small) to the comp.lang.perl.announce
+Usenet newsgroup. This will at least ensure very wide once-off
+distribution.
+
+If possible, register the module with CPAN. You should
+include details of its location in your announcement.
+
+Some notes about ftp archives: Please use a long descriptive file
+name that includes the version number. Most incoming directories
+will not be readable/listable, i.e., you won't be able to see your
+file after uploading it. Remember to send your email notification
+message as soon as possible after uploading else your file may get
+deleted automatically. Allow time for the file to be processed
+and/or check the file has been processed before announcing its
+location.
+
+FTP Archives for Perl Modules:
+
+Follow the instructions and links on:
+
+ http://www.cpan.org/modules/00modlist.long.html
+ http://www.cpan.org/modules/04pause.html
+
+or upload to one of these sites:
+
+ https://pause.kbx.de/pause/
+ http://pause.perl.org/
+
+and notify <modules@perl.org>.
+
+By using the WWW interface you can ask the Upload Server to mirror
+your modules from your ftp or WWW site into your own directory on
+CPAN!
+
+Please remember to send me an updated entry for the Module list!
+
+=item *
+
+Take care when changing a released module.
+
+Always strive to remain compatible with previous released versions.
+Otherwise try to add a mechanism to revert to the
+old behavior if people rely on it. Document incompatible changes.
+
+=back
+
+=head2 Guidelines for Converting Perl 4 Library Scripts into Modules
+
+=over 4
+
+=item *
+
+There is no requirement to convert anything.
+
+If it ain't broke, don't fix it! Perl 4 library scripts should
+continue to work with no problems. You may need to make some minor
+changes (like escaping non-array @'s in double quoted strings) but
+there is no need to convert a .pl file into a Module for just that.
+
+=item *
+
+Consider the implications.
+
+All Perl applications that make use of the script will need to
+be changed (slightly) if the script is converted into a module. Is
+it worth it unless you plan to make other changes at the same time?
+
+=item *
+
+Make the most of the opportunity.
+
+If you are going to convert the script to a module you can use the
+opportunity to redesign the interface. The guidelines for module
+creation above include many of the issues you should consider.
+
+=item *
+
+The pl2pm utility will get you started.
+
+This utility will read *.pl files (given as parameters) and write
+corresponding *.pm files. The pl2pm utilities does the following:
+
+=over 10
+
+=item *
+
+Adds the standard Module prologue lines
+
+=item *
+
+Converts package specifiers from ' to ::
+
+=item *
+
+Converts die(...) to croak(...)
+
+=item *
+
+Several other minor changes
+
+=back
+
+Being a mechanical process pl2pm is not bullet proof. The converted
+code will need careful checking, especially any package statements.
+Don't delete the original .pl file till the new .pm one works!
+
+=back
+
+=head2 Guidelines for Reusing Application Code
+
+=over 4
+
+=item *
+
+Complete applications rarely belong in the Perl Module Library.
+
+=item *
+
+Many applications contain some Perl code that could be reused.
+
+Help save the world! Share your code in a form that makes it easy
+to reuse.
+
+=item *
+
+Break-out the reusable code into one or more separate module files.
+
+=item *
+
+Take the opportunity to reconsider and redesign the interfaces.
+
+=item *
+
+In some cases the 'application' can then be reduced to a small
+
+fragment of code built on top of the reusable modules. In these cases
+the application could invoked as:
+
+ % perl -e 'use Module::Name; method(@ARGV)' ...
+or
+ % perl -mModule::Name ... (in perl5.002 or higher)
+
+=back
+
+=back
+
+=head1 NOTE
+
+Perl does not enforce private and public parts of its modules as you may
+have been used to in other languages like C++, Ada, or Modula-17. Perl
+doesn't have an infatuation with enforced privacy. It would prefer
+that you stayed out of its living room because you weren't invited, not
+because it has a shotgun.
+
+The module and its user have a contract, part of which is common law,
+and part of which is "written". Part of the common law contract is
+that a module doesn't pollute any namespace it wasn't asked to. The
+written contract for the module (A.K.A. documentation) may make other
+provisions. But then you know when you C<use RedefineTheWorld> that
+you're redefining the world and willing to take the consequences.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmodstyle.pod b/Master/tlpkg/tlperl/lib/pods/perlmodstyle.pod
new file mode 100644
index 00000000000..dfe5662f942
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmodstyle.pod
@@ -0,0 +1,780 @@
+=head1 NAME
+
+perlmodstyle - Perl module style guide
+
+=head1 INTRODUCTION
+
+This document attempts to describe the Perl Community's "best practice"
+for writing Perl modules. It extends the recommendations found in
+L<perlstyle> , which should be considered required reading
+before reading this document.
+
+While this document is intended to be useful to all module authors, it is
+particularly aimed at authors who wish to publish their modules on CPAN.
+
+The focus is on elements of style which are visible to the users of a
+module, rather than those parts which are only seen by the module's
+developers. However, many of the guidelines presented in this document
+can be extrapolated and applied successfully to a module's internals.
+
+This document differs from L<perlnewmod> in that it is a style guide
+rather than a tutorial on creating CPAN modules. It provides a
+checklist against which modules can be compared to determine whether
+they conform to best practice, without necessarily describing in detail
+how to achieve this.
+
+All the advice contained in this document has been gleaned from
+extensive conversations with experienced CPAN authors and users. Every
+piece of advice given here is the result of previous mistakes. This
+information is here to help you avoid the same mistakes and the extra
+work that would inevitably be required to fix them.
+
+The first section of this document provides an itemized checklist;
+subsequent sections provide a more detailed discussion of the items on
+the list. The final section, "Common Pitfalls", describes some of the
+most popular mistakes made by CPAN authors.
+
+=head1 QUICK CHECKLIST
+
+For more detail on each item in this checklist, see below.
+
+=head2 Before you start
+
+=over 4
+
+=item *
+
+Don't re-invent the wheel
+
+=item *
+
+Patch, extend or subclass an existing module where possible
+
+=item *
+
+Do one thing and do it well
+
+=item *
+
+Choose an appropriate name
+
+=back
+
+=head2 The API
+
+=over 4
+
+=item *
+
+API should be understandable by the average programmer
+
+=item *
+
+Simple methods for simple tasks
+
+=item *
+
+Separate functionality from output
+
+=item *
+
+Consistent naming of subroutines or methods
+
+=item *
+
+Use named parameters (a hash or hashref) when there are more than two
+parameters
+
+=back
+
+=head2 Stability
+
+=over 4
+
+=item *
+
+Ensure your module works under C<use strict> and C<-w>
+
+=item *
+
+Stable modules should maintain backwards compatibility
+
+=back
+
+=head2 Documentation
+
+=over 4
+
+=item *
+
+Write documentation in POD
+
+=item *
+
+Document purpose, scope and target applications
+
+=item *
+
+Document each publically accessible method or subroutine, including params and return values
+
+=item *
+
+Give examples of use in your documentation
+
+=item *
+
+Provide a README file and perhaps also release notes, changelog, etc
+
+=item *
+
+Provide links to further information (URL, email)
+
+=back
+
+=head2 Release considerations
+
+=over 4
+
+=item *
+
+Specify pre-requisites in Makefile.PL or Build.PL
+
+=item *
+
+Specify Perl version requirements with C<use>
+
+=item *
+
+Include tests with your module
+
+=item *
+
+Choose a sensible and consistent version numbering scheme (X.YY is the common Perl module numbering scheme)
+
+=item *
+
+Increment the version number for every change, no matter how small
+
+=item *
+
+Package the module using "make dist"
+
+=item *
+
+Choose an appropriate license (GPL/Artistic is a good default)
+
+=back
+
+=head1 BEFORE YOU START WRITING A MODULE
+
+Try not to launch headlong into developing your module without spending
+some time thinking first. A little forethought may save you a vast
+amount of effort later on.
+
+=head2 Has it been done before?
+
+You may not even need to write the module. Check whether it's already
+been done in Perl, and avoid re-inventing the wheel unless you have a
+good reason.
+
+Good places to look for pre-existing modules include
+http://search.cpan.org/ and asking on modules@perl.org
+
+If an existing module B<almost> does what you want, consider writing a
+patch, writing a subclass, or otherwise extending the existing module
+rather than rewriting it.
+
+=head2 Do one thing and do it well
+
+At the risk of stating the obvious, modules are intended to be modular.
+A Perl developer should be able to use modules to put together the
+building blocks of their application. However, it's important that the
+blocks are the right shape, and that the developer shouldn't have to use
+a big block when all they need is a small one.
+
+Your module should have a clearly defined scope which is no longer than
+a single sentence. Can your module be broken down into a family of
+related modules?
+
+Bad example:
+
+"FooBar.pm provides an implementation of the FOO protocol and the
+related BAR standard."
+
+Good example:
+
+"Foo.pm provides an implementation of the FOO protocol. Bar.pm
+implements the related BAR protocol."
+
+This means that if a developer only needs a module for the BAR standard,
+they should not be forced to install libraries for FOO as well.
+
+=head2 What's in a name?
+
+Make sure you choose an appropriate name for your module early on. This
+will help people find and remember your module, and make programming
+with your module more intuitive.
+
+When naming your module, consider the following:
+
+=over 4
+
+=item *
+
+Be descriptive (i.e. accurately describes the purpose of the module).
+
+=item *
+
+Be consistent with existing modules.
+
+=item *
+
+Reflect the functionality of the module, not the implementation.
+
+=item *
+
+Avoid starting a new top-level hierarchy, especially if a suitable
+hierarchy already exists under which you could place your module.
+
+=back
+
+You should contact modules@perl.org to ask them about your module name
+before publishing your module. You should also try to ask people who
+are already familiar with the module's application domain and the CPAN
+naming system. Authors of similar modules, or modules with similar
+names, may be a good place to start.
+
+=head1 DESIGNING AND WRITING YOUR MODULE
+
+Considerations for module design and coding:
+
+=head2 To OO or not to OO?
+
+Your module may be object oriented (OO) or not, or it may have both kinds
+of interfaces available. There are pros and cons of each technique, which
+should be considered when you design your API.
+
+According to Damian Conway, you should consider using OO:
+
+=over 4
+
+=item *
+
+When the system is large or likely to become so
+
+=item *
+
+When the data is aggregated in obvious structures that will become objects
+
+=item *
+
+When the types of data form a natural hierarchy that can make use of inheritance
+
+=item *
+
+When operations on data vary according to data type (making
+polymorphic invocation of methods feasible)
+
+=item *
+
+When it is likely that new data types may be later introduced
+into the system, and will need to be handled by existing code
+
+=item *
+
+When interactions between data are best represented by
+overloaded operators
+
+=item *
+
+When the implementation of system components is likely to
+change over time (and hence should be encapsulated)
+
+=item *
+
+When the system design is itself object-oriented
+
+=item *
+
+When large amounts of client code will use the software (and
+should be insulated from changes in its implementation)
+
+=item *
+
+When many separate operations will need to be applied to the
+same set of data
+
+=back
+
+Think carefully about whether OO is appropriate for your module.
+Gratuitous object orientation results in complex APIs which are
+difficult for the average module user to understand or use.
+
+=head2 Designing your API
+
+Your interfaces should be understandable by an average Perl programmer.
+The following guidelines may help you judge whether your API is
+sufficiently straightforward:
+
+=over 4
+
+=item Write simple routines to do simple things.
+
+It's better to have numerous simple routines than a few monolithic ones.
+If your routine changes its behaviour significantly based on its
+arguments, it's a sign that you should have two (or more) separate
+routines.
+
+=item Separate functionality from output.
+
+Return your results in the most generic form possible and allow the user
+to choose how to use them. The most generic form possible is usually a
+Perl data structure which can then be used to generate a text report,
+HTML, XML, a database query, or whatever else your users require.
+
+If your routine iterates through some kind of list (such as a list of
+files, or records in a database) you may consider providing a callback
+so that users can manipulate each element of the list in turn.
+File::Find provides an example of this with its
+C<find(\&wanted, $dir)> syntax.
+
+=item Provide sensible shortcuts and defaults.
+
+Don't require every module user to jump through the same hoops to achieve a
+simple result. You can always include optional parameters or routines for
+more complex or non-standard behaviour. If most of your users have to
+type a few almost identical lines of code when they start using your
+module, it's a sign that you should have made that behaviour a default.
+Another good indicator that you should use defaults is if most of your
+users call your routines with the same arguments.
+
+=item Naming conventions
+
+Your naming should be consistent. For instance, it's better to have:
+
+ display_day();
+ display_week();
+ display_year();
+
+than
+
+ display_day();
+ week_display();
+ show_year();
+
+This applies equally to method names, parameter names, and anything else
+which is visible to the user (and most things that aren't!)
+
+=item Parameter passing
+
+Use named parameters. It's easier to use a hash like this:
+
+ $obj->do_something(
+ name => "wibble",
+ type => "text",
+ size => 1024,
+ );
+
+... than to have a long list of unnamed parameters like this:
+
+ $obj->do_something("wibble", "text", 1024);
+
+While the list of arguments might work fine for one, two or even three
+arguments, any more arguments become hard for the module user to
+remember, and hard for the module author to manage. If you want to add
+a new parameter you will have to add it to the end of the list for
+backward compatibility, and this will probably make your list order
+unintuitive. Also, if many elements may be undefined you may see the
+following unattractive method calls:
+
+ $obj->do_something(undef, undef, undef, undef, undef, undef, 1024);
+
+Provide sensible defaults for parameters which have them. Don't make
+your users specify parameters which will almost always be the same.
+
+The issue of whether to pass the arguments in a hash or a hashref is
+largely a matter of personal style.
+
+The use of hash keys starting with a hyphen (C<-name>) or entirely in
+upper case (C<NAME>) is a relic of older versions of Perl in which
+ordinary lower case strings were not handled correctly by the C<=E<gt>>
+operator. While some modules retain uppercase or hyphenated argument
+keys for historical reasons or as a matter of personal style, most new
+modules should use simple lower case keys. Whatever you choose, be
+consistent!
+
+=back
+
+=head2 Strictness and warnings
+
+Your module should run successfully under the strict pragma and should
+run without generating any warnings. Your module should also handle
+taint-checking where appropriate, though this can cause difficulties in
+many cases.
+
+=head2 Backwards compatibility
+
+Modules which are "stable" should not break backwards compatibility
+without at least a long transition phase and a major change in version
+number.
+
+=head2 Error handling and messages
+
+When your module encounters an error it should do one or more of:
+
+=over 4
+
+=item *
+
+Return an undefined value.
+
+=item *
+
+set C<$Module::errstr> or similar (C<errstr> is a common name used by
+DBI and other popular modules; if you choose something else, be sure to
+document it clearly).
+
+=item *
+
+C<warn()> or C<carp()> a message to STDERR.
+
+=item *
+
+C<croak()> only when your module absolutely cannot figure out what to
+do. (C<croak()> is a better version of C<die()> for use within
+modules, which reports its errors from the perspective of the caller.
+See L<Carp> for details of C<croak()>, C<carp()> and other useful
+routines.)
+
+=item *
+
+As an alternative to the above, you may prefer to throw exceptions using
+the Error module.
+
+=back
+
+Configurable error handling can be very useful to your users. Consider
+offering a choice of levels for warning and debug messages, an option to
+send messages to a separate file, a way to specify an error-handling
+routine, or other such features. Be sure to default all these options
+to the commonest use.
+
+=head1 DOCUMENTING YOUR MODULE
+
+=head2 POD
+
+Your module should include documentation aimed at Perl developers.
+You should use Perl's "plain old documentation" (POD) for your general
+technical documentation, though you may wish to write additional
+documentation (white papers, tutorials, etc) in some other format.
+You need to cover the following subjects:
+
+=over 4
+
+=item *
+
+A synopsis of the common uses of the module
+
+=item *
+
+The purpose, scope and target applications of your module
+
+=item *
+
+Use of each publically accessible method or subroutine, including
+parameters and return values
+
+=item *
+
+Examples of use
+
+=item *
+
+Sources of further information
+
+=item *
+
+A contact email address for the author/maintainer
+
+=back
+
+The level of detail in Perl module documentation generally goes from
+less detailed to more detailed. Your SYNOPSIS section should contain a
+minimal example of use (perhaps as little as one line of code; skip the
+unusual use cases or anything not needed by most users); the
+DESCRIPTION should describe your module in broad terms, generally in
+just a few paragraphs; more detail of the module's routines or methods,
+lengthy code examples, or other in-depth material should be given in
+subsequent sections.
+
+Ideally, someone who's slightly familiar with your module should be able
+to refresh their memory without hitting "page down". As your reader
+continues through the document, they should receive a progressively
+greater amount of knowledge.
+
+The recommended order of sections in Perl module documentation is:
+
+=over 4
+
+=item *
+
+NAME
+
+=item *
+
+SYNOPSIS
+
+=item *
+
+DESCRIPTION
+
+=item *
+
+One or more sections or subsections giving greater detail of available
+methods and routines and any other relevant information.
+
+=item *
+
+BUGS/CAVEATS/etc
+
+=item *
+
+AUTHOR
+
+=item *
+
+SEE ALSO
+
+=item *
+
+COPYRIGHT and LICENSE
+
+=back
+
+Keep your documentation near the code it documents ("inline"
+documentation). Include POD for a given method right above that
+method's subroutine. This makes it easier to keep the documentation up
+to date, and avoids having to document each piece of code twice (once in
+POD and once in comments).
+
+=head2 README, INSTALL, release notes, changelogs
+
+Your module should also include a README file describing the module and
+giving pointers to further information (website, author email).
+
+An INSTALL file should be included, and should contain simple installation
+instructions. When using ExtUtils::MakeMaker this will usually be:
+
+=over 4
+
+=item perl Makefile.PL
+
+=item make
+
+=item make test
+
+=item make install
+
+=back
+
+When using Module::Build, this will usually be:
+
+=over 4
+
+=item perl Build.PL
+
+=item perl Build
+
+=item perl Build test
+
+=item perl Build install
+
+=back
+
+Release notes or changelogs should be produced for each release of your
+software describing user-visible changes to your module, in terms
+relevant to the user.
+
+=head1 RELEASE CONSIDERATIONS
+
+=head2 Version numbering
+
+Version numbers should indicate at least major and minor releases, and
+possibly sub-minor releases. A major release is one in which most of
+the functionality has changed, or in which major new functionality is
+added. A minor release is one in which a small amount of functionality
+has been added or changed. Sub-minor version numbers are usually used
+for changes which do not affect functionality, such as documentation
+patches.
+
+The most common CPAN version numbering scheme looks like this:
+
+ 1.00, 1.10, 1.11, 1.20, 1.30, 1.31, 1.32
+
+A correct CPAN version number is a floating point number with at least
+2 digits after the decimal. You can test whether it conforms to CPAN by
+using
+
+ perl -MExtUtils::MakeMaker -le 'print MM->parse_version(shift)' 'Foo.pm'
+
+If you want to release a 'beta' or 'alpha' version of a module but
+don't want CPAN.pm to list it as most recent use an '_' after the
+regular version number followed by at least 2 digits, eg. 1.20_01. If
+you do this, the following idiom is recommended:
+
+ $VERSION = "1.12_01";
+ $XS_VERSION = $VERSION; # only needed if you have XS code
+ $VERSION = eval $VERSION;
+
+With that trick MakeMaker will only read the first line and thus read
+the underscore, while the perl interpreter will evaluate the $VERSION
+and convert the string into a number. Later operations that treat
+$VERSION as a number will then be able to do so without provoking a
+warning about $VERSION not being a number.
+
+Never release anything (even a one-word documentation patch) without
+incrementing the number. Even a one-word documentation patch should
+result in a change in version at the sub-minor level.
+
+=head2 Pre-requisites
+
+Module authors should carefully consider whether to rely on other
+modules, and which modules to rely on.
+
+Most importantly, choose modules which are as stable as possible. In
+order of preference:
+
+=over 4
+
+=item *
+
+Core Perl modules
+
+=item *
+
+Stable CPAN modules
+
+=item *
+
+Unstable CPAN modules
+
+=item *
+
+Modules not available from CPAN
+
+=back
+
+Specify version requirements for other Perl modules in the
+pre-requisites in your Makefile.PL or Build.PL.
+
+Be sure to specify Perl version requirements both in Makefile.PL or
+Build.PL and with C<require 5.6.1> or similar. See the section on
+C<use VERSION> of L<perlfunc/require> for details.
+
+=head2 Testing
+
+All modules should be tested before distribution (using "make disttest"),
+and the tests should also be available to people installing the modules
+(using "make test").
+For Module::Build you would use the C<make test> equivalent C<perl Build test>.
+
+The importance of these tests is proportional to the alleged stability of a
+module. A module which purports to be stable or which hopes to achieve wide
+use should adhere to as strict a testing regime as possible.
+
+Useful modules to help you write tests (with minimum impact on your
+development process or your time) include Test::Simple, Carp::Assert
+and Test::Inline.
+For more sophisticated test suites there are Test::More and Test::MockObject.
+
+=head2 Packaging
+
+Modules should be packaged using one of the standard packaging tools.
+Currently you have the choice between ExtUtils::MakeMaker and the
+more platform independent Module::Build, allowing modules to be installed in a
+consistent manner.
+When using ExtUtils::MakeMaker, you can use "make dist" to create your
+package. Tools exist to help you to build your module in a MakeMaker-friendly
+style. These include ExtUtils::ModuleMaker and h2xs. See also L<perlnewmod>.
+
+=head2 Licensing
+
+Make sure that your module has a license, and that the full text of it
+is included in the distribution (unless it's a common one and the terms
+of the license don't require you to include it).
+
+If you don't know what license to use, dual licensing under the GPL
+and Artistic licenses (the same as Perl itself) is a good idea.
+See L<perlgpl> and L<perlartistic>.
+
+=head1 COMMON PITFALLS
+
+=head2 Reinventing the wheel
+
+There are certain application spaces which are already very, very well
+served by CPAN. One example is templating systems, another is date and
+time modules, and there are many more. While it is a rite of passage to
+write your own version of these things, please consider carefully
+whether the Perl world really needs you to publish it.
+
+=head2 Trying to do too much
+
+Your module will be part of a developer's toolkit. It will not, in
+itself, form the B<entire> toolkit. It's tempting to add extra features
+until your code is a monolithic system rather than a set of modular
+building blocks.
+
+=head2 Inappropriate documentation
+
+Don't fall into the trap of writing for the wrong audience. Your
+primary audience is a reasonably experienced developer with at least
+a moderate understanding of your module's application domain, who's just
+downloaded your module and wants to start using it as quickly as possible.
+
+Tutorials, end-user documentation, research papers, FAQs etc are not
+appropriate in a module's main documentation. If you really want to
+write these, include them as sub-documents such as C<My::Module::Tutorial> or
+C<My::Module::FAQ> and provide a link in the SEE ALSO section of the
+main documentation.
+
+=head1 SEE ALSO
+
+=over 4
+
+=item L<perlstyle>
+
+General Perl style guide
+
+=item L<perlnewmod>
+
+How to create a new module
+
+=item L<perlpod>
+
+POD documentation
+
+=item L<podchecker>
+
+Verifies your POD's correctness
+
+=item Packaging Tools
+
+L<ExtUtils::MakeMaker>, L<Module::Build>
+
+=item Testing tools
+
+L<Test::Simple>, L<Test::Inline>, L<Carp::Assert>, L<Test::More>, L<Test::MockObject>
+
+=item http://pause.perl.org/
+
+Perl Authors Upload Server. Contains links to information for module
+authors.
+
+=item Any good book on software engineering
+
+=back
+
+=head1 AUTHOR
+
+Kirrily "Skud" Robert <skud@cpan.org>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmpeix.pod b/Master/tlpkg/tlperl/lib/pods/perlmpeix.pod
new file mode 100644
index 00000000000..f3cbe8e7bb8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmpeix.pod
@@ -0,0 +1,711 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+README.mpeix - Perl/iX for HP e3000 MPE
+
+=head1 SYNOPSIS
+
+ http://www.bixby.org/mark/perlix.html
+ Perl language for MPE
+ Last updated January 12, 2006 @ 2100 UTC
+
+
+=head1 NOTE
+
+This is a podified version of what used to be on the above-mentioned web page,
+podified by Jarkko Hietaniemi 2001-Jan-01.
+
+=head1 What's New in Perl for MPE/iX
+
+January 12, 2006
+
+=over 4
+
+=item *
+
+Updated for perl-5.8.8 and perl-5.9.3 by Ken Hirsch.
+
+Simplified the build process by using the MPEAUTOCONF
+functionality in Mark Klein's ld.
+
+If you build this from scratch, make sure you have a version
+of ld which supports it. In the shell, type
+
+ ld --help
+ and look for AUTOCONF or MPEAUTOCONF near the bottom
+
+ or do this:
+ ld --help 2>&1 | grep AUTOCONF
+
+If you see don't see AUTOCONF or MPEAUTOCONF, make sure you get a new
+version.
+
+You also do not have to use mpeix/relink after building, so the
+recommend sequence is:
+
+ ./Configure -de
+
+ # or ./Configure -de -Dusedevel
+ # if you're building a development version
+
+ make
+ make test
+ # if you run this in a job, do "make test_notty"
+
+ make install
+
+Be prepared for a wait. These take much longer on MPE/iX than on a Unix
+system, because of a slow forking, mostly. On a lightly-loaded HP3000
+Series 979 running MPE/iX 7.5:
+
+ Configure: 1 hour
+ make: 1 hour 15 minutes
+ make test 1 hour 45 minutes
+
+Various socket problems were fixed in mpeix.c.
+
+Mark Klein provided a fixed sigsetjmp (that works with dynamic
+libraries) in mpeix_setjmp.c
+
+=back
+
+June 1, 2000
+
+=over 4
+
+=item *
+
+Rebuilt to be compatible with mod_perl. If you plan on using
+mod_perl, you MUST download and install this version of Perl/iX!
+
+=item *
+
+uselargefiles="undef": not available in MPE for POSIX files yet.
+
+=item *
+
+Now bundled with various add-on packages:
+
+=over 8
+
+=item *
+
+libnet (as seen on CPAN)
+
+=item *
+
+libwww-perl (LWP) which lets Perl programs behave like web browsers:
+
+=item *
+
+mod_perl (just the perl portion; the actual DSO will be released
+soon with Apache/iX 1.3.12 from bixby.org). This module allows you to
+write high performance persistent Perl CGI scripts and all sorts of
+cool things. (http://perl.apache.org/)
+
+and much much more hiding under /PERL/PUB/.cpan/
+
+=item *
+
+The CPAN module now works for automatic downloading and
+installing of add-on packages:
+
+ 1. export FTP_PASSIVE=1
+ 2. perl -MCPAN -e shell
+ 3. Ignore any terminal I/O related complaints!
+
+(http://search.cpan.org/dist/CPAN/)
+
+=back
+
+=back
+
+May 20, 2000
+
+=over 4
+
+=item *
+
+Updated to version 5.6.0. Builds straight out of the box on MPE/iX.
+
+=item *
+
+Perl's getpwnam() function which had regressed to being
+unimplemented on MPE is now implemented once again.
+
+=back
+
+September 17, 1999
+
+=over 4
+
+=item *
+
+Migrated from cccd.edu to bixby.org.
+
+=back
+
+=head1 Welcome to Perl/iX
+
+This is the official home page for the HP e3000 MPE/iX
+( http://www.hp.com/go/e3000 ) port of the Perl scripting
+language ( http://www.perl.com/ ) which gives you all of the power of C,
+awk, sed, and sh in a single language. Check here for the latest news,
+implemented functionality, known bugs, to-do list, etc. Status reports
+about major milestones will also be posted to the HP3000-L mailing list
+( http://www.lsoft.com/scripts/wl.exe?SL1=HP3000-L&H=RAVEN.UTC.EDU ) and
+its associated gatewayed newsgroup comp.sys.hp.mpe.
+
+I'm doing this port because I can't live without Perl on the Unix
+machines that I administer, and I want to have the same power
+available to me on MPE.
+
+Please send your comments, questions, and bug reports directly to me,
+Mark Bixby ( http://www.bixby.org/mark/ ). Or just post them to HP3000-L.
+
+The platform I'm using to do this port is an HP 3000 957RX running
+MPE/iX 6.0 and using the GNU gcc C compiler
+( http://jazz.external.hp.com/src/gnu/gnuframe.html ).
+
+The combined porting wisdom from all of my ports can be found in my
+MPE/iX Porting Guide (http://www.bixby.org/mark/porting.html).
+
+IMPORTANT NOTICE: Yes, I do work for the HP CSY R&D lab, but ALL of
+the software you download from bixby.org is my personal freeware that
+is NOT supported by HP.
+
+=head1 System Requirements for Perl/iX
+
+=over 4
+
+=item *
+
+MPE/iX 5.5 or later. This version of Perl/iX does NOT run on
+MPE/iX 5.0 or earlier, nor does it run on "classic" MPE/V machines.
+
+=item *
+
+If you wish to recompile Perl, you must install both GNUCORE and
+GNUGCC from jazz (http://jazz.external.hp.com/src/gnu/gnuframe.html).
+
+=item *
+
+Perl/iX will be happier on MPE/iX 5.5 if you install the MPEKX40B
+extended POSIX filename characters patch, but this is optional.
+
+=item *
+
+Patch LBCJXT6A is required on MPE/iX 5.5 machines in order to
+prevent Perl/iX from dying with an unresolved external reference
+to _getenv_libc.
+
+=item *
+
+If you will be compiling Perl/iX yourself, you will also need
+Syslog/iX ( http://www.bixby.org/mark/syslogix.html ) and the
+/BIND/PUB/include and /BIND/PUB/lib portions of BIND/iX
+( http://www.bixby.org/mark/bindix.html ).
+
+=back
+
+=head1 How to Obtain Perl/iX
+
+=over 4
+
+=item 1.
+
+Download Perl using either FTP.ARPA.SYS or some other client
+
+=item 2.
+
+Extract the installation script
+
+=item 3.
+
+Edit the installation script
+
+=item 4.
+
+Run the installation script
+
+=item 5.
+
+Convert your *.a system archive libraries to *.sl shared libraries
+
+=back
+
+Download Perl using FTP.ARPA.SYS from your HP 3000 (the preferred
+method).....
+
+ :HELLO MANAGER.SYS
+ :XEQ FTP.ARPA.SYS
+ open ftp.bixby.org
+ anonymous
+ your@email.address
+ bytestream
+ cd /pub/mpe
+ get perl-5.6.0-mpe.tar.Z /tmp/perl.tar.Z;disc=2147483647
+ exit
+
+.....Or download using some other generic web or ftp client (the alternate
+method)
+
+Download the following files (make sure that you use "binary mode" or
+whatever client feature that is 8-bit clean):
+
+=over 4
+
+=item *
+
+Perl from
+
+ http://www.bixby.org/ftp/pub/mpe/perl-5.6.0-mpe.tar.Z
+
+or
+
+ ftp://ftp.bixby.org/pub/mpe/perl-5.6.0-mpe.tar.Z
+
+=item *
+
+Upload those files to your HP 3000 in an 8-bit clean bytestream manner to:
+
+ /tmp/perl.tar.Z
+
+=item *
+
+Then extract the installation script (after both download methods)
+
+ :CHDIR /tmp
+ :XEQ TAR.HPBIN.SYS 'xvfopz /tmp/perl.tar.Z INSTALL'
+
+=item *
+
+Edit the installation script
+
+Examine the accounting structure creation commands and modify if
+necessary (adding additional capabilities, choosing a non-system
+volume set, etc).
+
+ :XEQ VI.HPBIN.SYS /tmp/INSTALL
+
+=item *
+
+Run the installation script.
+
+The accounting structure will be created and then all files will be
+extracted from the archive.
+
+ :XEQ SH.HPBIN.SYS /tmp/INSTALL
+
+=item *
+
+Convert your *.a system archive libraries to *.sl shared libraries
+
+You only have to do this ONCE on your MPE/iX 5.5 machine in order to
+convert /lib/lib*.a and /usr/lib/lib*.a libraries to their *.sl
+equivalents. This step should not be necessary on MPE/iX 6.0 or later
+machines because the 6.0 or later update process does it for you.
+
+ :XEQ SH.HPBIN.SYS /PERL/PUB/LIBSHP3K
+
+=back
+
+=head1 Perl/iX Distribution Contents Highlights
+
+=over 4
+
+=item README
+
+The file you're reading now.
+
+=item INSTALL
+
+Perl/iX Installation script.
+
+=item LIBSHP3K
+
+Script to convert *.a system archive libraries to *.sl shared libraries.
+
+=item PERL
+
+Perl NMPRG executable. A version-numbered backup copy also
+exists. You might wish to "ln -s /PERL/PUB/PERL /usr/local/bin/perl".
+
+=item .cpan/
+
+Much add-on source code downloaded with the CPAN module.
+
+=item lib/
+
+Perl libraries, both core and add-on.
+
+=item man/
+
+Perl man page documentation.
+
+=item public_html/feedback.cgi
+
+Sample feedback CGI form written in Perl.
+
+=item src/perl-5.6.0-mpe
+
+Source code.
+
+=back
+
+=head1 How to Compile Perl/iX
+
+=over 4
+
+=item 1.
+
+cd src/perl-5.6.0-mpe
+
+=item 2.
+
+Read the INSTALL file for the official instructions
+
+=item 3.
+
+./Configure -d
+
+=item 4.
+
+make
+
+=item 5.
+
+./mpeix/relink
+
+=item 6.
+
+make test (expect approximately 15 out of 11306 subtests to fail,
+mostly due to MPE not supporting hard links, UDP socket problems,
+and handling exit() return codes improperly)
+
+=item 7.
+
+make install
+
+=item 8.
+
+Optionally create symbolic links that point to the Perl
+executable, i.e. ln -s /PERL/PUB/PERL /usr/local/bin/perl
+
+=back
+
+The summary test results from "cd t; ./perl -I../lib harness":
+
+ Failed Test Status Wstat Total Fail Failed List of failed
+ ---------------------------------------------------------------------------
+ io/fs.t 29 8 27.59% 2-5, 7-9, 11
+ io/openpid.t 10 1 10.00% 7
+ lib/io_sock.t 14 1 7.14% 13
+ lib/io_udp.t 7 2 28.57% 3, 5
+ lib/posix.t 27 1 3.70% 12
+ op/lex_assign.t 187 1 0.53% 13
+ op/stat.t 58 1 1.72% 3
+ 15 tests and 94 subtests skipped.
+ Failed 7/236 test scripts, 97.03% okay. 15/11306 subtests failed, 99.87% okay.
+
+=head1 Getting Started with Perl/iX
+
+Create your Perl script files with "#!/PERL/PUB/perl" (or an
+equivalent symbolic link) as the first line. Use the chmod command to
+make sure that your script has execute permission. Run your script!
+
+Be sure to take a look at the CPAN module list
+( http://www.cpan.org/CPAN.html ). A wide variety of free Perl software
+is available. You can automatically download these packages by using
+the CPAN module ( http://search.cpan.org/dist/CPAN/ ).
+
+=head1 MPE/iX Implementation Considerations
+
+There some minor functionality issues to be aware of when comparing
+Perl for Unix (Perl/UX) to Perl/iX:
+
+=over 4
+
+=item *
+
+MPE gcc/ld doesn't properly support linking NMPRG executables against
+NMXL dynamic libraries, so you must manually run mpeix/relink after
+each re-build of Perl.
+
+=item *
+
+Perl/iX File::Copy will use MPE's /bin/cp command to copy files by
+name in order to preserve file attributes like file code.
+
+=item *
+
+MPE (and thus Perl/iX) lacks support for setgrent(), endgrent(),
+setpwent(), endpwent().
+
+=item *
+
+MPE (and thus Perl/iX) lacks support for hard links.
+
+=item *
+
+MPE requires GETPRIVMODE() in order to bind() to ports less than 1024.
+Perl/iX will call GETPRIVMODE() automatically on your behalf if you
+attempt to bind() to these low-numbered ports. Note that the Perl/iX
+executable and the PERL account do not normally have CAP=PM, so if you
+will be bind()-ing to these privileged ports, you will manually need
+to add PM capability as appropriate.
+
+=item *
+
+MPE requires that you bind() to an IP address of zero. Perl/iX
+automatically replaces the IP address that you pass to bind() with
+a zero.
+
+=item *
+
+MPE requires GETPRIVMODE() in order to setuid(). There are too many
+calls to setuid() within Perl/iX, so I have not attempted an automatic
+GETPRIVMODE() solution similar to bind().
+
+=back
+
+=head1 Known Perl/iX Bugs Under Investigation
+
+None.
+
+=head1 Perl/iX To-Do List
+
+=over 4
+
+=item *
+
+Make setuid()/setgid() support work.
+
+=item *
+
+Make sure that fcntl() against a socket descriptor is redirected to sfcntl().
+
+=item *
+
+Add support for Berkeley DB once I've finished porting Berkeley DB.
+
+=item *
+
+Write an MPE XS extension library containing miscellaneous important
+MPE functions like GETPRIVMODE(), GETUSERMODE(), and sfcntl().
+
+=back
+
+=head1 Perl/iX Change History
+
+May 6, 1999
+
+=over 4
+
+=item *
+
+Patch LBCJXT6A is required on MPE/iX 5.5 machines in order to prevent
+Perl/iX from dying with an unresolved external reference to _getenv_libc.
+
+=back
+
+April 7, 1999
+
+=over 4
+
+=item *
+
+Updated to version 5.005_03.
+
+=item *
+
+The official source distribution once again compiles "straight out
+of the box" for MPE.
+
+=item *
+
+The current incarnation of the 5.5 POSIX filename extended
+characters patch is now MPEKX40B.
+
+=item *
+
+The LIBSHP3K *.a -> *.sl library conversion script is now included
+as /PERL/PUB/LIBSHP3K.
+
+=back
+
+November 20, 1998
+
+=over 4
+
+=item *
+
+Updated to version 5.005_02.
+
+=item *
+
+Fixed a DynaLoader bug that was unable to load symbols from relative
+path name libraries.
+
+=item *
+
+Fixed a .xs compilation bug where the mpeixish.sh include file wasn't
+being installed into the proper directory.
+
+=item *
+
+All bugfixes will be submitted back to the official Perl developers.
+
+=item *
+
+The current incarnation of the POSIX filename extended characters
+patch is now MPEKXJ3A.
+
+=back
+
+August 14, 1998
+
+=over 4
+
+=item *
+
+The previous POSIX filename extended characters patch MPEKX44C has
+been superseded by MPEKXB5A.
+
+=back
+
+August 7, 1998
+
+=over 4
+
+=item *
+
+The previous POSIX filename extended characters patch MPEKX76A has
+been superseded by MPEKX44C.
+
+=back
+
+July 28, 1998
+
+=over 4
+
+=item *
+
+Updated to version 5.005_01.
+
+=back
+
+July 23, 1998
+
+=over 4
+
+=item *
+
+Updated to version 5.005 (production release). The public
+freeware sources are now 100% MPE-ready "straight out of the box".
+
+=back
+
+July 17, 1998
+
+=over 4
+
+=item *
+
+Updated to version 5.005b1 (public beta release). The public
+freeware sources are now 99.9% MPE-ready. By installing and
+testing this beta on your own HP3000, you will be helping to
+insure that the final release of 5.005 will be 100% MPE-ready and
+100% bug free.
+
+=item *
+
+My MPE binary release is now extracted using my standard INSTALL script.
+
+=back
+
+July 15, 1998
+
+=over 4
+
+=item *
+
+Changed startperl to #!/PERL/PUB/perl so that Perl will recognize
+scripts more easily and efficiently.
+
+=back
+
+July 8, 1998
+
+=over 4
+
+=item *
+
+Updated to version 5.004_70 (internal developer release) which is now
+MPE-ready. The next public freeware release of Perl should compile
+"straight out of the box" on MPE. Note that this version of Perl/iX
+was strictly internal to me and never publicly released. Note that
+[21]BIND/iX is now required (well, the include files and libbind.a) if
+you wish to compile Perl/iX.
+
+=back
+
+November 6, 1997
+
+=over 4
+
+=item *
+
+Updated to version 5.004_04. No changes in MPE-specific functionality.
+
+=back
+
+October 16, 1997
+
+=over 4
+
+=item *
+
+Added Demos section to the Perl/iX home page so you can see some
+sample Perl applications running on my 3000.
+
+=back
+
+October 3, 1997
+
+=over 4
+
+=item *
+
+Added System Requirements section to the Perl/iX home page just so the
+prerequisites stand out more. Various other home page tweaks.
+
+=back
+
+October 2, 1997
+
+=over 4
+
+=item *
+
+Initial public release.
+
+=back
+
+September 1997
+
+=over 4
+
+=item *
+
+Porting begins.
+
+=back
+
+=head1 AUTHOR
+
+Mark Bixby, http://www.bixby.org/mark/
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlmroapi.pod b/Master/tlpkg/tlperl/lib/pods/perlmroapi.pod
new file mode 100644
index 00000000000..2200becded2
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlmroapi.pod
@@ -0,0 +1,94 @@
+=head1 NAME
+
+perlmroapi - Perl method resolution plugin interface
+
+=head1 DESCRIPTION
+
+As of Perl 5.10.1 there is a new interface for plugging and using method
+resolution orders other than the default (linear depth first search).
+The C3 method resolution order added in 5.10.0 has been re-implemented as
+a plugin, without changing its Perl-space interface.
+
+Each plugin should register itself with C<Perl_mro_register> by providing
+the following structure
+
+ struct mro_alg {
+ AV *(*resolve)(pTHX_ HV *stash, U32 level);
+ const char *name;
+ U16 length;
+ U16 kflags;
+ U32 hash;
+ };
+
+=over 4
+
+=item resolve
+
+Pointer to the linearisation function, described below.
+
+=item name
+
+Name of the MRO, either in ISO-8859-1 or UTF-8.
+
+=item length
+
+Length of the name.
+
+=item kflags
+
+If the name is given in UTF-8, set this to C<HVhek_UTF8>. The value is passed
+direct as the parameter I<kflags> to C<hv_common()>.
+
+=item hash
+
+A precomputed hash value for the MRO's name, or 0.
+
+=back
+
+=head1 Callbacks
+
+The C<resolve> function is called to generate a linearised ISA for the
+given stash, using this MRO. It is called with a pointer to the stash, and
+a I<level> of 0. The core always sets I<level> to 0 when it calls your
+function - the parameter is provided to allow your implementation to track
+depth if it needs to recurse.
+
+The function should return a reference to an array containing the parent
+classes in order. The caller is responsible for incrementing the reference
+count if it wants to keep the structure. Hence if you have created a
+temporary value that you keep no pointer to, C<sv_2mortal()> to ensure that
+it is disposed of correctly. If you have cached your return value, then
+return a pointer to it without changing the reference count.
+
+=head1 Caching
+
+Computing MROs can be expensive. The implementation provides a cache, in
+which you can store a single C<SV *>, or anything that can be cast to
+C<SV *>, such as C<AV *>. To read your private value, use the macro
+C<MRO_GET_PRIVATE_DATA()>, passing it the C<mro_meta> structure from the
+stash, and a pointer to your C<mro_alg> structure:
+
+ meta = HvMROMETA(stash);
+ private_sv = MRO_GET_PRIVATE_DATA(meta, &my_mro_alg);
+
+To set your private value, call C<Perl_mro_set_private_data()>:
+
+ Perl_mro_set_private_data(aTHX_ meta, &c3_alg, private_sv);
+
+The private data cache will take ownership of a reference to private_sv,
+much the same way that C<hv_store()> takes ownership of a reference to the
+value that you pass it.
+
+=head1 Examples
+
+For examples of MRO implementations, see C<S_mro_get_linear_isa_c3()>
+and the C<BOOT:> section of F<mro/mro.xs>, and C<S_mro_get_linear_isa_dfs()>
+in F<mro.c>
+
+=head1 AUTHORS
+
+The implementation of the C3 MRO and switchable MROs within the perl core was
+written by Brandon L Black. Nicholas Clark created the pluggable interface,
+refactored Brandon's implementation to work with it, and wrote this document.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlnetware.pod b/Master/tlpkg/tlperl/lib/pods/perlnetware.pod
new file mode 100644
index 00000000000..1e92b84890a
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlnetware.pod
@@ -0,0 +1,214 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+perlnetware - Perl for NetWare
+
+=head1 DESCRIPTION
+
+This file gives instructions for building Perl 5.7 and above, and also
+Perl modules for NetWare. Before you start, you may want to read the
+README file found in the top level directory into which the Perl source
+code distribution was extracted. Make sure you read and understand
+the terms under which the software is being distributed.
+
+=head1 BUILD
+
+This section describes the steps to be performed to build a Perl NLM
+and other associated NLMs.
+
+=head2 Tools & SDK
+
+The build requires CodeWarrior compiler and linker. In addition,
+the "NetWare SDK", "NLM & NetWare Libraries for C" and
+"NetWare Server Protocol Libraries for C", all available at
+L<http://developer.novell.com/wiki/index.php/Category:Novell_Developer_Kit>,
+are required. Microsoft Visual C++ version 4.2 or later is also
+required.
+
+=head2 Setup
+
+The build process is dependent on the location of the NetWare SDK.
+Once the Tools & SDK are installed, the build environment has to
+be setup. The following batch files setup the environment.
+
+=over 4
+
+=item SetNWBld.bat
+
+The Execution of this file takes 2 parameters as input. The first
+being the NetWare SDK path, second being the path for CodeWarrior
+Compiler & tools. Execution of this file sets these paths and also
+sets the build type to Release by default.
+
+=item Buildtype.bat
+
+This is used to set the build type to debug or release. Change the
+build type only after executing SetNWBld.bat
+
+=item *
+
+Example:
+ 1. Typing "buildtype d on" at the command prompt causes the buildtype
+ to be set to Debug type with D2 flag set.
+ 2. Typing "buildtype d off" or "buildtype d" at the command prompt causes
+ the buildtype to be set to Debug type with D1 flag set.
+ 2. Typing "buildtype r" at the command prompt sets it to Release Build type.
+
+=back
+
+=head2 Make
+
+The make process runs only under WinNT shell. The NetWare makefile is
+located under the NetWare folder. This makes use of miniperl.exe to
+run some of the Perl scripts. To create miniperl.exe, first set the
+required paths for Visual c++ compilier (specify vcvars32 location) at
+the command prompt. Then run nmake from win32 folder through WinNT
+command prompt. The build process can be stopped after miniperl.exe
+is created. Then run nmake from NetWare folder through WinNT command
+prompt.
+
+Currently the following two build types are tested on NetWare:
+
+=over 4
+
+=item *
+
+USE_MULTI, USE_ITHREADS & USE_IMP_SYS defined
+
+=item *
+
+USE_MULTI & USE_IMP_SYS defined and USE_ITHREADS not defined
+
+=back
+
+=head2 Interpreter
+
+Once miniperl.exe creation is over, run nmake from the NetWare folder.
+This will build the Perl interpreter for NetWare as I<perl.nlm>.
+This is copied under the I<Release> folder if you are doing
+a release build, else will be copied under I<Debug> folder for debug builds.
+
+=head2 Extensions
+
+The make process also creates the Perl extensions as I<<Extension>.nlm>
+
+=head1 INSTALL
+
+To install NetWare Perl onto a NetWare server, first map the Sys
+volume of a NetWare server to I<i:>. This is because the makefile by
+default sets the drive letter to I<i:>. Type I<nmake nwinstall> from
+NetWare folder on a WinNT command prompt. This will copy the binaries
+and module files onto the NetWare server under I<sys:\Perl>
+folder. The Perl interpreter, I<perl.nlm>, is copied under
+I<sys:\perl\system> folder. Copy this to I<sys:\system> folder.
+
+Example: At the command prompt Type "nmake nwinstall".
+ This will install NetWare Perl on the NetWare Server.
+ Similiarly if you type "nmake install",
+ This will cause the binaries to be installed on the local machine.
+ (Typically under the c:\perl folder)
+
+=head1 BUILD NEW EXTENSIONS
+
+To build extensions other than standard extensions, NetWare Perl has
+to be installed on Windows along with Windows Perl. The Perl for
+Windows can be either downloaded from the CPAN site and built using
+the sources, or the binaries can be directly downloaded from the
+ActiveState site. Installation can be done by invoking I<nmake
+install> from the NetWare folder on a WinNT command prompt after
+building NetWare Perl by following steps given above. This will copy
+all the *.pm files and other required files. Documentation files are
+not copied. Thus one must first install Windows Perl, Then install
+NetWare Perl.
+
+Once this is done, do the following to build any extension:
+
+=over 4
+
+=item *
+
+Change to the extension directory where its source files are present.
+
+=item *
+
+Run the following command at the command prompt:
+
+ perl -II<path to NetWare lib dir> -II<path to lib> Makefile.pl
+
+Example:
+
+ perl -Ic:/perl/5.6.1/lib/NetWare-x86-multi-thread -Ic:\perl\5.6.1\lib MakeFile.pl
+
+or
+
+ perl -Ic:/perl/5.8.0/lib/NetWare-x86-multi-thread -Ic:\perl\5.8.0\lib MakeFile.pl
+
+=item *
+
+nmake
+
+=item *
+
+nmake install
+
+Install will copy the files into the Windows machine where NetWare
+Perl is installed and these files may have to be copied to the NetWare
+server manually. Alternatively, pass I<INSTALLSITELIB=i:\perl\lib> as
+an input to makefile.pl above. Here I<i:> is the mapped drive to the
+sys: volume of the server where Perl on NetWare is installed. Now
+typing I<nmake install>, will copy the files onto the NetWare server.
+
+Example: You can execute the following on the command prompt.
+
+ perl -Ic:/perl/5.6.1/lib/NetWare-x86-multi-thread -Ic:\perl\5.6.1\lib MakeFile.pl
+ INSTALLSITELIB=i:\perl\lib
+
+or
+
+ perl -Ic:/perl/5.8.0/lib/NetWare-x86-multi-thread -Ic:\perl\5.8.0\lib MakeFile.pl
+ INSTALLSITELIB=i:\perl\lib
+
+=item *
+
+Note: Some modules downloaded from CPAN may require NetWare related
+API in order to build on NetWare. Other modules may however build
+smoothly with or without minor changes depending on the type of
+module.
+
+=back
+
+=head1 ACKNOWLEDGEMENTS
+
+The makefile for Win32 is used as a reference to create the makefile
+for NetWare. Also, the make process for NetWare port uses
+miniperl.exe to run scripts during the make and installation process.
+
+=head1 AUTHORS
+
+Anantha Kesari H Y (hyanantha@novell.com)
+Aditya C (caditya@novell.com)
+
+=head1 DATE
+
+=over 4
+
+=item *
+
+Created - 18 Jan 2001
+
+=item *
+
+Modified - 25 June 2001
+
+=item *
+
+Modified - 13 July 2001
+
+=item *
+
+Modified - 28 May 2002
+
+=back
diff --git a/Master/tlpkg/tlperl/lib/pods/perlnewmod.pod b/Master/tlpkg/tlperl/lib/pods/perlnewmod.pod
new file mode 100644
index 00000000000..7555f974a80
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlnewmod.pod
@@ -0,0 +1,280 @@
+=head1 NAME
+
+perlnewmod - preparing a new module for distribution
+
+=head1 DESCRIPTION
+
+This document gives you some suggestions about how to go about writing
+Perl modules, preparing them for distribution, and making them available
+via CPAN.
+
+One of the things that makes Perl really powerful is the fact that Perl
+hackers tend to want to share the solutions to problems they've faced,
+so you and I don't have to battle with the same problem again.
+
+The main way they do this is by abstracting the solution into a Perl
+module. If you don't know what one of these is, the rest of this
+document isn't going to be much use to you. You're also missing out on
+an awful lot of useful code; consider having a look at L<perlmod>,
+L<perlmodlib> and L<perlmodinstall> before coming back here.
+
+When you've found that there isn't a module available for what you're
+trying to do, and you've had to write the code yourself, consider
+packaging up the solution into a module and uploading it to CPAN so that
+others can benefit.
+
+=head2 Warning
+
+We're going to primarily concentrate on Perl-only modules here, rather
+than XS modules. XS modules serve a rather different purpose, and
+you should consider different things before distributing them - the
+popularity of the library you are gluing, the portability to other
+operating systems, and so on. However, the notes on preparing the Perl
+side of the module and packaging and distributing it will apply equally
+well to an XS module as a pure-Perl one.
+
+=head2 What should I make into a module?
+
+You should make a module out of any code that you think is going to be
+useful to others. Anything that's likely to fill a hole in the communal
+library and which someone else can slot directly into their program. Any
+part of your code which you can isolate and extract and plug into
+something else is a likely candidate.
+
+Let's take an example. Suppose you're reading in data from a local
+format into a hash-of-hashes in Perl, turning that into a tree, walking
+the tree and then piping each node to an Acme Transmogrifier Server.
+
+Now, quite a few people have the Acme Transmogrifier, and you've had to
+write something to talk the protocol from scratch - you'd almost
+certainly want to make that into a module. The level at which you pitch
+it is up to you: you might want protocol-level modules analogous to
+L<Net::SMTP|Net::SMTP> which then talk to higher level modules analogous
+to L<Mail::Send|Mail::Send>. The choice is yours, but you do want to get
+a module out for that server protocol.
+
+Nobody else on the planet is going to talk your local data format, so we
+can ignore that. But what about the thing in the middle? Building tree
+structures from Perl variables and then traversing them is a nice,
+general problem, and if nobody's already written a module that does
+that, you might want to modularise that code too.
+
+So hopefully you've now got a few ideas about what's good to modularise.
+Let's now see how it's done.
+
+=head2 Step-by-step: Preparing the ground
+
+Before we even start scraping out the code, there are a few things we'll
+want to do in advance.
+
+=over 3
+
+=item Look around
+
+Dig into a bunch of modules to see how they're written. I'd suggest
+starting with L<Text::Tabs|Text::Tabs>, since it's in the standard
+library and is nice and simple, and then looking at something a little
+more complex like L<File::Copy|File::Copy>. For object oriented
+code, C<WWW::Mechanize> or the C<Email::*> modules provide some good
+examples.
+
+These should give you an overall feel for how modules are laid out and
+written.
+
+=item Check it's new
+
+There are a lot of modules on CPAN, and it's easy to miss one that's
+similar to what you're planning on contributing. Have a good plough
+through the L<http://search.cpan.org> and make sure you're not the one
+reinventing the wheel!
+
+=item Discuss the need
+
+You might love it. You might feel that everyone else needs it. But there
+might not actually be any real demand for it out there. If you're unsure
+about the demand your module will have, consider sending out feelers
+on the C<comp.lang.perl.modules> newsgroup, or as a last resort, ask the
+modules list at C<modules@perl.org>. Remember that this is a closed list
+with a very long turn-around time - be prepared to wait a good while for
+a response from them.
+
+=item Choose a name
+
+Perl modules included on CPAN have a naming hierarchy you should try to
+fit in with. See L<perlmodlib> for more details on how this works, and
+browse around CPAN and the modules list to get a feel of it. At the very
+least, remember this: modules should be title capitalised, (This::Thing)
+fit in with a category, and explain their purpose succinctly.
+
+=item Check again
+
+While you're doing that, make really sure you haven't missed a module
+similar to the one you're about to write.
+
+When you've got your name sorted out and you're sure that your module is
+wanted and not currently available, it's time to start coding.
+
+=back
+
+=head2 Step-by-step: Making the module
+
+=over 3
+
+=item Start with F<module-starter> or F<h2xs>
+
+The F<module-starter> utility is distributed as part of the
+L<Module::Starter|Module::Starter> CPAN package. It creates a directory
+with stubs of all the necessary files to start a new module, according
+to recent "best practice" for module development, and is invoked from
+the command line, thus:
+
+ module-starter --module=Foo::Bar \
+ --author="Your Name" --email=yourname@cpan.org
+
+If you do not wish to install the L<Module::Starter|Module::Starter>
+package from CPAN, F<h2xs> is an older tool, originally intended for the
+development of XS modules, which comes packaged with the Perl
+distribution.
+
+A typical invocation of L<h2xs|h2xs> for a pure Perl module is:
+
+ h2xs -AX --skip-exporter --use-new-tests -n Foo::Bar
+
+The C<-A> omits the Autoloader code, C<-X> omits XS elements,
+C<--skip-exporter> omits the Exporter code, C<--use-new-tests> sets up a
+modern testing environment, and C<-n> specifies the name of the module.
+
+=item Use L<strict|strict> and L<warnings|warnings>
+
+A module's code has to be warning and strict-clean, since you can't
+guarantee the conditions that it'll be used under. Besides, you wouldn't
+want to distribute code that wasn't warning or strict-clean anyway,
+right?
+
+=item Use L<Carp|Carp>
+
+The L<Carp|Carp> module allows you to present your error messages from
+the caller's perspective; this gives you a way to signal a problem with
+the caller and not your module. For instance, if you say this:
+
+ warn "No hostname given";
+
+the user will see something like this:
+
+ No hostname given at /usr/local/lib/perl5/site_perl/5.6.0/Net/Acme.pm
+ line 123.
+
+which looks like your module is doing something wrong. Instead, you want
+to put the blame on the user, and say this:
+
+ No hostname given at bad_code, line 10.
+
+You do this by using L<Carp|Carp> and replacing your C<warn>s with
+C<carp>s. If you need to C<die>, say C<croak> instead. However, keep
+C<warn> and C<die> in place for your sanity checks - where it really is
+your module at fault.
+
+=item Use L<Exporter|Exporter> - wisely!
+
+L<Exporter|Exporter> gives you a standard way of exporting symbols and
+subroutines from your module into the caller's namespace. For instance,
+saying C<use Net::Acme qw(&frob)> would import the C<frob> subroutine.
+
+The package variable C<@EXPORT> will determine which symbols will get
+exported when the caller simply says C<use Net::Acme> - you will hardly
+ever want to put anything in there. C<@EXPORT_OK>, on the other hand,
+specifies which symbols you're willing to export. If you do want to
+export a bunch of symbols, use the C<%EXPORT_TAGS> and define a standard
+export set - look at L<Exporter> for more details.
+
+=item Use L<plain old documentation|perlpod>
+
+The work isn't over until the paperwork is done, and you're going to
+need to put in some time writing some documentation for your module.
+C<module-starter> or C<h2xs> will provide a stub for you to fill in; if
+you're not sure about the format, look at L<perlpod> for an
+introduction. Provide a good synopsis of how your module is used in
+code, a description, and then notes on the syntax and function of the
+individual subroutines or methods. Use Perl comments for developer notes
+and POD for end-user notes.
+
+=item Write tests
+
+You're encouraged to create self-tests for your module to ensure it's
+working as intended on the myriad platforms Perl supports; if you upload
+your module to CPAN, a host of testers will build your module and send
+you the results of the tests. Again, C<module-starter> and C<h2xs>
+provide a test framework which you can extend - you should do something
+more than just checking your module will compile.
+L<Test::Simple|Test::Simple> and L<Test::More|Test::More> are good
+places to start when writing a test suite.
+
+=item Write the README
+
+If you're uploading to CPAN, the automated gremlins will extract the
+README file and place that in your CPAN directory. It'll also appear in
+the main F<by-module> and F<by-category> directories if you make it onto
+the modules list. It's a good idea to put here what the module actually
+does in detail, and the user-visible changes since the last release.
+
+=back
+
+=head2 Step-by-step: Distributing your module
+
+=over 3
+
+=item Get a CPAN user ID
+
+Every developer publishing modules on CPAN needs a CPAN ID. Visit
+C<http://pause.perl.org/>, select "Request PAUSE Account", and wait for
+your request to be approved by the PAUSE administrators.
+
+=item C<perl Makefile.PL; make test; make dist>
+
+Once again, C<module-starter> or C<h2xs> has done all the work for you.
+They produce the standard C<Makefile.PL> you see when you download and
+install modules, and this produces a Makefile with a C<dist> target.
+
+Once you've ensured that your module passes its own tests - always a
+good thing to make sure - you can C<make dist>, and the Makefile will
+hopefully produce you a nice tarball of your module, ready for upload.
+
+=item Upload the tarball
+
+The email you got when you received your CPAN ID will tell you how to
+log in to PAUSE, the Perl Authors Upload SErver. From the menus there,
+you can upload your module to CPAN.
+
+=item Announce to the modules list
+
+Once uploaded, it'll sit unnoticed in your author directory. If you want
+it connected to the rest of the CPAN, you'll need to go to "Register
+Namespace" on PAUSE. Once registered, your module will appear in the
+by-module and by-category listings on CPAN.
+
+=item Announce to clpa
+
+If you have a burning desire to tell the world about your release, post
+an announcement to the moderated C<comp.lang.perl.announce> newsgroup.
+
+=item Fix bugs!
+
+Once you start accumulating users, they'll send you bug reports. If
+you're lucky, they'll even send you patches. Welcome to the joys of
+maintaining a software project...
+
+=back
+
+=head1 AUTHOR
+
+Simon Cozens, C<simon@cpan.org>
+
+Updated by Kirrily "Skud" Robert, C<skud@cpan.org>
+
+=head1 SEE ALSO
+
+L<perlmod>, L<perlmodlib>, L<perlmodinstall>, L<h2xs>, L<strict>,
+L<Carp>, L<Exporter>, L<perlpod>, L<Test::Simple>, L<Test::More>
+L<ExtUtils::MakeMaker>, L<Module::Build>, L<Module::Starter>
+http://www.cpan.org/ , Ken Williams's tutorial on building your own
+module at http://mathforum.org/~ken/perl_modules.html
diff --git a/Master/tlpkg/tlperl/lib/pods/perlnumber.pod b/Master/tlpkg/tlperl/lib/pods/perlnumber.pod
new file mode 100644
index 00000000000..ffe3ed5b432
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlnumber.pod
@@ -0,0 +1,209 @@
+=head1 NAME
+
+perlnumber - semantics of numbers and numeric operations in Perl
+
+=head1 SYNOPSIS
+
+ $n = 1234; # decimal integer
+ $n = 0b1110011; # binary integer
+ $n = 01234; # octal integer
+ $n = 0x1234; # hexadecimal integer
+ $n = 12.34e-56; # exponential notation
+ $n = "-12.34e56"; # number specified as a string
+ $n = "1234"; # number specified as a string
+
+=head1 DESCRIPTION
+
+This document describes how Perl internally handles numeric values.
+
+Perl's operator overloading facility is completely ignored here. Operator
+overloading allows user-defined behaviors for numbers, such as operations
+over arbitrarily large integers, floating points numbers with arbitrary
+precision, operations over "exotic" numbers such as modular arithmetic or
+p-adic arithmetic, and so on. See L<overload> for details.
+
+=head1 Storing numbers
+
+Perl can internally represent numbers in 3 different ways: as native
+integers, as native floating point numbers, and as decimal strings.
+Decimal strings may have an exponential notation part, as in C<"12.34e-56">.
+I<Native> here means "a format supported by the C compiler which was used
+to build perl".
+
+The term "native" does not mean quite as much when we talk about native
+integers, as it does when native floating point numbers are involved.
+The only implication of the term "native" on integers is that the limits for
+the maximal and the minimal supported true integral quantities are close to
+powers of 2. However, "native" floats have a most fundamental
+restriction: they may represent only those numbers which have a relatively
+"short" representation when converted to a binary fraction. For example,
+0.9 cannot be represented by a native float, since the binary fraction
+for 0.9 is infinite:
+
+ binary0.1110011001100...
+
+with the sequence C<1100> repeating again and again. In addition to this
+limitation, the exponent of the binary number is also restricted when it
+is represented as a floating point number. On typical hardware, floating
+point values can store numbers with up to 53 binary digits, and with binary
+exponents between -1024 and 1024. In decimal representation this is close
+to 16 decimal digits and decimal exponents in the range of -304..304.
+The upshot of all this is that Perl cannot store a number like
+12345678901234567 as a floating point number on such architectures without
+loss of information.
+
+Similarly, decimal strings can represent only those numbers which have a
+finite decimal expansion. Being strings, and thus of arbitrary length, there
+is no practical limit for the exponent or number of decimal digits for these
+numbers. (But realize that what we are discussing the rules for just the
+I<storage> of these numbers. The fact that you can store such "large" numbers
+does not mean that the I<operations> over these numbers will use all
+of the significant digits.
+See L<"Numeric operators and numeric conversions"> for details.)
+
+In fact numbers stored in the native integer format may be stored either
+in the signed native form, or in the unsigned native form. Thus the limits
+for Perl numbers stored as native integers would typically be -2**31..2**32-1,
+with appropriate modifications in the case of 64-bit integers. Again, this
+does not mean that Perl can do operations only over integers in this range:
+it is possible to store many more integers in floating point format.
+
+Summing up, Perl numeric values can store only those numbers which have
+a finite decimal expansion or a "short" binary expansion.
+
+=head1 Numeric operators and numeric conversions
+
+As mentioned earlier, Perl can store a number in any one of three formats,
+but most operators typically understand only one of those formats. When
+a numeric value is passed as an argument to such an operator, it will be
+converted to the format understood by the operator.
+
+Six such conversions are possible:
+
+ native integer --> native floating point (*)
+ native integer --> decimal string
+ native floating_point --> native integer (*)
+ native floating_point --> decimal string (*)
+ decimal string --> native integer
+ decimal string --> native floating point (*)
+
+These conversions are governed by the following general rules:
+
+=over 4
+
+=item *
+
+If the source number can be represented in the target form, that
+representation is used.
+
+=item *
+
+If the source number is outside of the limits representable in the target form,
+a representation of the closest limit is used. (I<Loss of information>)
+
+=item *
+
+If the source number is between two numbers representable in the target form,
+a representation of one of these numbers is used. (I<Loss of information>)
+
+=item *
+
+In C<< native floating point --> native integer >> conversions the magnitude
+of the result is less than or equal to the magnitude of the source.
+(I<"Rounding to zero".>)
+
+=item *
+
+If the C<< decimal string --> native integer >> conversion cannot be done
+without loss of information, the result is compatible with the conversion
+sequence C<< decimal_string --> native_floating_point --> native_integer >>.
+In particular, rounding is strongly biased to 0, though a number like
+C<"0.99999999999999999999"> has a chance of being rounded to 1.
+
+=back
+
+B<RESTRICTION>: The conversions marked with C<(*)> above involve steps
+performed by the C compiler. In particular, bugs/features of the compiler
+used may lead to breakage of some of the above rules.
+
+=head1 Flavors of Perl numeric operations
+
+Perl operations which take a numeric argument treat that argument in one
+of four different ways: they may force it to one of the integer/floating/
+string formats, or they may behave differently depending on the format of
+the operand. Forcing a numeric value to a particular format does not
+change the number stored in the value.
+
+All the operators which need an argument in the integer format treat the
+argument as in modular arithmetic, e.g., C<mod 2**32> on a 32-bit
+architecture. C<sprintf "%u", -1> therefore provides the same result as
+C<sprintf "%u", ~0>.
+
+=over 4
+
+=item Arithmetic operators
+
+The binary operators C<+> C<-> C<*> C</> C<%> C<==> C<!=> C<E<gt>> C<E<lt>>
+C<E<gt>=> C<E<lt>=> and the unary operators C<-> C<abs> and C<--> will
+attempt to convert arguments to integers. If both conversions are possible
+without loss of precision, and the operation can be performed without
+loss of precision then the integer result is used. Otherwise arguments are
+converted to floating point format and the floating point result is used.
+The caching of conversions (as described above) means that the integer
+conversion does not throw away fractional parts on floating point numbers.
+
+=item ++
+
+C<++> behaves as the other operators above, except that if it is a string
+matching the format C</^[a-zA-Z]*[0-9]*\z/> the string increment described
+in L<perlop> is used.
+
+=item Arithmetic operators during C<use integer>
+
+In scopes where C<use integer;> is in force, nearly all the operators listed
+above will force their argument(s) into integer format, and return an integer
+result. The exceptions, C<abs>, C<++> and C<-->, do not change their
+behavior with C<use integer;>
+
+=item Other mathematical operators
+
+Operators such as C<**>, C<sin> and C<exp> force arguments to floating point
+format.
+
+=item Bitwise operators
+
+Arguments are forced into the integer format if not strings.
+
+=item Bitwise operators during C<use integer>
+
+forces arguments to integer format. Also shift operations internally use
+signed integers rather than the default unsigned.
+
+=item Operators which expect an integer
+
+force the argument into the integer format. This is applicable
+to the third and fourth arguments of C<sysread>, for example.
+
+=item Operators which expect a string
+
+force the argument into the string format. For example, this is
+applicable to C<printf "%s", $value>.
+
+=back
+
+Though forcing an argument into a particular form does not change the
+stored number, Perl remembers the result of such conversions. In
+particular, though the first such conversion may be time-consuming,
+repeated operations will not need to redo the conversion.
+
+=head1 AUTHOR
+
+Ilya Zakharevich C<ilya@math.ohio-state.edu>
+
+Editorial adjustments by Gurusamy Sarathy <gsar@ActiveState.com>
+
+Updates for 5.8.0 by Nicholas Clark <nick@ccl4.org>
+
+=head1 SEE ALSO
+
+L<overload>, L<perlop>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlobj.pod b/Master/tlpkg/tlperl/lib/pods/perlobj.pod
new file mode 100644
index 00000000000..fdecd84a688
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlobj.pod
@@ -0,0 +1,595 @@
+=head1 NAME
+X<object> X<OOP>
+
+perlobj - Perl objects
+
+=head1 DESCRIPTION
+
+First you need to understand what references are in Perl.
+See L<perlref> for that. Second, if you still find the following
+reference work too complicated, a tutorial on object-oriented programming
+in Perl can be found in L<perltoot> and L<perltooc>.
+
+If you're still with us, then
+here are three very simple definitions that you should find reassuring.
+
+=over 4
+
+=item 1.
+
+An object is simply a reference that happens to know which class it
+belongs to.
+
+=item 2.
+
+A class is simply a package that happens to provide methods to deal
+with object references.
+
+=item 3.
+
+A method is simply a subroutine that expects an object reference (or
+a package name, for class methods) as the first argument.
+
+=back
+
+We'll cover these points now in more depth.
+
+=head2 An Object is Simply a Reference
+X<object> X<bless> X<constructor> X<new>
+
+Unlike say C++, Perl doesn't provide any special syntax for
+constructors. A constructor is merely a subroutine that returns a
+reference to something "blessed" into a class, generally the
+class that the subroutine is defined in. Here is a typical
+constructor:
+
+ package Critter;
+ sub new { bless {} }
+
+That word C<new> isn't special. You could have written
+a construct this way, too:
+
+ package Critter;
+ sub spawn { bless {} }
+
+This might even be preferable, because the C++ programmers won't
+be tricked into thinking that C<new> works in Perl as it does in C++.
+It doesn't. We recommend that you name your constructors whatever
+makes sense in the context of the problem you're solving. For example,
+constructors in the Tk extension to Perl are named after the widgets
+they create.
+
+One thing that's different about Perl constructors compared with those in
+C++ is that in Perl, they have to allocate their own memory. (The other
+things is that they don't automatically call overridden base-class
+constructors.) The C<{}> allocates an anonymous hash containing no
+key/value pairs, and returns it The bless() takes that reference and
+tells the object it references that it's now a Critter, and returns
+the reference. This is for convenience, because the referenced object
+itself knows that it has been blessed, and the reference to it could
+have been returned directly, like this:
+
+ sub new {
+ my $self = {};
+ bless $self;
+ return $self;
+ }
+
+You often see such a thing in more complicated constructors
+that wish to call methods in the class as part of the construction:
+
+ sub new {
+ my $self = {};
+ bless $self;
+ $self->initialize();
+ return $self;
+ }
+
+If you care about inheritance (and you should; see
+L<perlmodlib/"Modules: Creation, Use, and Abuse">),
+then you want to use the two-arg form of bless
+so that your constructors may be inherited:
+
+ sub new {
+ my $class = shift;
+ my $self = {};
+ bless $self, $class;
+ $self->initialize();
+ return $self;
+ }
+
+Or if you expect people to call not just C<< CLASS->new() >> but also
+C<< $obj->new() >>, then use something like the following. (Note that using
+this to call new() on an instance does not automatically perform any
+copying. If you want a shallow or deep copy of an object, you'll have to
+specifically allow for that.) The initialize() method used will be of
+whatever $class we blessed the object into:
+
+ sub new {
+ my $this = shift;
+ my $class = ref($this) || $this;
+ my $self = {};
+ bless $self, $class;
+ $self->initialize();
+ return $self;
+ }
+
+Within the class package, the methods will typically deal with the
+reference as an ordinary reference. Outside the class package,
+the reference is generally treated as an opaque value that may
+be accessed only through the class's methods.
+
+Although a constructor can in theory re-bless a referenced object
+currently belonging to another class, this is almost certainly going
+to get you into trouble. The new class is responsible for all
+cleanup later. The previous blessing is forgotten, as an object
+may belong to only one class at a time. (Although of course it's
+free to inherit methods from many classes.) If you find yourself
+having to do this, the parent class is probably misbehaving, though.
+
+A clarification: Perl objects are blessed. References are not. Objects
+know which package they belong to. References do not. The bless()
+function uses the reference to find the object. Consider
+the following example:
+
+ $a = {};
+ $b = $a;
+ bless $a, BLAH;
+ print "\$b is a ", ref($b), "\n";
+
+This reports $b as being a BLAH, so obviously bless()
+operated on the object and not on the reference.
+
+=head2 A Class is Simply a Package
+X<class> X<package> X<@ISA> X<inheritance>
+
+Unlike say C++, Perl doesn't provide any special syntax for class
+definitions. You use a package as a class by putting method
+definitions into the class.
+
+There is a special array within each package called @ISA, which says
+where else to look for a method if you can't find it in the current
+package. This is how Perl implements inheritance. Each element of the
+@ISA array is just the name of another package that happens to be a
+class package. The classes are searched for missing methods in
+depth-first, left-to-right order by default (see L<mro> for alternative
+search order and other in-depth information). The classes accessible
+through @ISA are known as base classes of the current class.
+
+All classes implicitly inherit from class C<UNIVERSAL> as their
+last base class. Several commonly used methods are automatically
+supplied in the UNIVERSAL class; see L<"Default UNIVERSAL methods"> or
+L<UNIVERSAL|UNIVERSAL> for more details.
+X<UNIVERSAL> X<base class> X<class, base>
+
+If a missing method is found in a base class, it is cached
+in the current class for efficiency. Changing @ISA or defining new
+subroutines invalidates the cache and causes Perl to do the lookup again.
+
+If neither the current class, its named base classes, nor the UNIVERSAL
+class contains the requested method, these three places are searched
+all over again, this time looking for a method named AUTOLOAD(). If an
+AUTOLOAD is found, this method is called on behalf of the missing method,
+setting the package global $AUTOLOAD to be the fully qualified name of
+the method that was intended to be called.
+X<AUTOLOAD>
+
+If none of that works, Perl finally gives up and complains.
+
+If you want to stop the AUTOLOAD inheritance say simply
+X<AUTOLOAD>
+
+ sub AUTOLOAD;
+
+and the call will die using the name of the sub being called.
+
+Perl classes do method inheritance only. Data inheritance is left up
+to the class itself. By and large, this is not a problem in Perl,
+because most classes model the attributes of their object using an
+anonymous hash, which serves as its own little namespace to be carved up
+by the various classes that might want to do something with the object.
+The only problem with this is that you can't sure that you aren't using
+a piece of the hash that isn't already used. A reasonable workaround
+is to prepend your fieldname in the hash with the package name.
+X<inheritance, method> X<inheritance, data>
+
+ sub bump {
+ my $self = shift;
+ $self->{ __PACKAGE__ . ".count"}++;
+ }
+
+=head2 A Method is Simply a Subroutine
+X<method>
+
+Unlike say C++, Perl doesn't provide any special syntax for method
+definition. (It does provide a little syntax for method invocation
+though. More on that later.) A method expects its first argument
+to be the object (reference) or package (string) it is being invoked
+on. There are two ways of calling methods, which we'll call class
+methods and instance methods.
+
+A class method expects a class name as the first argument. It
+provides functionality for the class as a whole, not for any
+individual object belonging to the class. Constructors are often
+class methods, but see L<perltoot> and L<perltooc> for alternatives.
+Many class methods simply ignore their first argument, because they
+already know what package they're in and don't care what package
+they were invoked via. (These aren't necessarily the same, because
+class methods follow the inheritance tree just like ordinary instance
+methods.) Another typical use for class methods is to look up an
+object by name:
+
+ sub find {
+ my ($class, $name) = @_;
+ $objtable{$name};
+ }
+
+An instance method expects an object reference as its first argument.
+Typically it shifts the first argument into a "self" or "this" variable,
+and then uses that as an ordinary reference.
+
+ sub display {
+ my $self = shift;
+ my @keys = @_ ? @_ : sort keys %$self;
+ foreach $key (@keys) {
+ print "\t$key => $self->{$key}\n";
+ }
+ }
+
+=head2 Method Invocation
+X<invocation> X<method> X<arrow> X<< -> >>
+
+For various historical and other reasons, Perl offers two equivalent
+ways to write a method call. The simpler and more common way is to use
+the arrow notation:
+
+ my $fred = Critter->find("Fred");
+ $fred->display("Height", "Weight");
+
+You should already be familiar with the use of the C<< -> >> operator with
+references. In fact, since C<$fred> above is a reference to an object,
+you could think of the method call as just another form of
+dereferencing.
+
+Whatever is on the left side of the arrow, whether a reference or a
+class name, is passed to the method subroutine as its first argument.
+So the above code is mostly equivalent to:
+
+ my $fred = Critter::find("Critter", "Fred");
+ Critter::display($fred, "Height", "Weight");
+
+How does Perl know which package the subroutine is in? By looking at
+the left side of the arrow, which must be either a package name or a
+reference to an object, i.e. something that has been blessed to a
+package. Either way, that's the package where Perl starts looking. If
+that package has no subroutine with that name, Perl starts looking for
+it in any base classes of that package, and so on.
+
+If you need to, you I<can> force Perl to start looking in some other package:
+
+ my $barney = MyCritter->Critter::find("Barney");
+ $barney->Critter::display("Height", "Weight");
+
+Here C<MyCritter> is presumably a subclass of C<Critter> that defines
+its own versions of find() and display(). We haven't specified what
+those methods do, but that doesn't matter above since we've forced Perl
+to start looking for the subroutines in C<Critter>.
+
+As a special case of the above, you may use the C<SUPER> pseudo-class to
+tell Perl to start looking for the method in the packages named in the
+current class's C<@ISA> list.
+X<SUPER>
+
+ package MyCritter;
+ use base 'Critter'; # sets @MyCritter::ISA = ('Critter');
+
+ sub display {
+ my ($self, @args) = @_;
+ $self->SUPER::display("Name", @args);
+ }
+
+It is important to note that C<SUPER> refers to the superclass(es) of the
+I<current package> and not to the superclass(es) of the object. Also, the
+C<SUPER> pseudo-class can only currently be used as a modifier to a method
+name, but not in any of the other ways that class names are normally used,
+eg:
+X<SUPER>
+
+ something->SUPER::method(...); # OK
+ SUPER::method(...); # WRONG
+ SUPER->method(...); # WRONG
+
+Instead of a class name or an object reference, you can also use any
+expression that returns either of those on the left side of the arrow.
+So the following statement is valid:
+
+ Critter->find("Fred")->display("Height", "Weight");
+
+and so is the following:
+
+ my $fred = (reverse "rettirC")->find(reverse "derF");
+
+The right side of the arrow typically is the method name, but a simple
+scalar variable containing either the method name or a subroutine
+reference can also be used.
+
+If the right side of the arrow is a scalar containing a reference
+to a subroutine, then this is equivalent to calling the referenced
+subroutine directly with the class name or object on the left side
+of the arrow as its first argument. No lookup is done and there is
+no requirement that the subroutine be defined in any package related
+to the class name or object on the left side of the arrow.
+
+For example, the following calls to $display are equivalent:
+
+ my $display = sub { my $self = shift; ... };
+ $fred->$display("Height", "Weight");
+ $display->($fred, "Height", "Weight");
+
+=head2 Indirect Object Syntax
+X<indirect object syntax> X<invocation, indirect> X<indirect>
+
+The other way to invoke a method is by using the so-called "indirect
+object" notation. This syntax was available in Perl 4 long before
+objects were introduced, and is still used with filehandles like this:
+
+ print STDERR "help!!!\n";
+
+The same syntax can be used to call either object or class methods.
+
+ my $fred = find Critter "Fred";
+ display $fred "Height", "Weight";
+
+Notice that there is no comma between the object or class name and the
+parameters. This is how Perl can tell you want an indirect method call
+instead of an ordinary subroutine call.
+
+But what if there are no arguments? In that case, Perl must guess what
+you want. Even worse, it must make that guess I<at compile time>.
+Usually Perl gets it right, but when it doesn't you get a function
+call compiled as a method, or vice versa. This can introduce subtle bugs
+that are hard to detect.
+
+For example, a call to a method C<new> in indirect notation (as C++
+programmers are wont to make) can be miscompiled into a subroutine
+call if there's already a C<new> function in scope. You'd end up
+calling the current package's C<new> as a subroutine, rather than the
+desired class's method. The compiler tries to cheat by remembering
+bareword C<require>s, but the grief when it messes up just isn't worth the
+years of debugging it will take you to track down such subtle bugs.
+
+There is another problem with this syntax: the indirect object is
+limited to a name, a scalar variable, or a block, because it would have
+to do too much lookahead otherwise, just like any other postfix
+dereference in the language. (These are the same quirky rules as are
+used for the filehandle slot in functions like C<print> and C<printf>.)
+This can lead to horribly confusing precedence problems, as in these
+next two lines:
+
+ move $obj->{FIELD}; # probably wrong!
+ move $ary[$i]; # probably wrong!
+
+Those actually parse as the very surprising:
+
+ $obj->move->{FIELD}; # Well, lookee here
+ $ary->move([$i]); # Didn't expect this one, eh?
+
+Rather than what you might have expected:
+
+ $obj->{FIELD}->move(); # You should be so lucky.
+ $ary[$i]->move; # Yeah, sure.
+
+To get the correct behavior with indirect object syntax, you would have
+to use a block around the indirect object:
+
+ move {$obj->{FIELD}};
+ move {$ary[$i]};
+
+Even then, you still have the same potential problem if there happens to
+be a function named C<move> in the current package. B<The C<< -> >>
+notation suffers from neither of these disturbing ambiguities, so we
+recommend you use it exclusively.> However, you may still end up having
+to read code using the indirect object notation, so it's important to be
+familiar with it.
+
+=head2 Default UNIVERSAL methods
+X<UNIVERSAL>
+
+The C<UNIVERSAL> package automatically contains the following methods that
+are inherited by all other classes:
+
+=over 4
+
+=item isa(CLASS)
+X<isa>
+
+C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS>
+
+=item DOES(ROLE)
+X<DOES>
+
+C<DOES> returns I<true> if its object claims to perform the role C<ROLE>. By
+default, this is equivalent to C<isa>.
+
+=item can(METHOD)
+X<can>
+
+C<can> checks to see if its object has a method called C<METHOD>,
+if it does then a reference to the sub is returned, if it does not then
+C<undef> is returned.
+
+=item VERSION( [NEED] )
+X<VERSION>
+
+C<VERSION> returns the version number of the class (package). If the
+NEED argument is given then it will check that the current version (as
+defined by the $VERSION variable in the given package) not less than
+NEED; it will die if this is not the case. This method is called automatically
+by the C<VERSION> form of C<use>.
+
+ use Package 1.2 qw(some imported subs);
+ # implies:
+ Package->VERSION(1.2);
+
+=back
+
+=head2 Destructors
+X<destructor> X<DESTROY>
+
+When the last reference to an object goes away, the object is
+automatically destroyed. (This may even be after you exit, if you've
+stored references in global variables.) If you want to capture control
+just before the object is freed, you may define a DESTROY method in
+your class. It will automatically be called at the appropriate moment,
+and you can do any extra cleanup you need to do. Perl passes a reference
+to the object under destruction as the first (and only) argument. Beware
+that the reference is a read-only value, and cannot be modified by
+manipulating C<$_[0]> within the destructor. The object itself (i.e.
+the thingy the reference points to, namely C<${$_[0]}>, C<@{$_[0]}>,
+C<%{$_[0]}> etc.) is not similarly constrained.
+
+Since DESTROY methods can be called at unpredictable times, it is
+important that you localise any global variables that the method may
+update. In particular, localise C<$@> if you use C<eval {}> and
+localise C<$?> if you use C<system> or backticks.
+
+If you arrange to re-bless the reference before the destructor returns,
+perl will again call the DESTROY method for the re-blessed object after
+the current one returns. This can be used for clean delegation of
+object destruction, or for ensuring that destructors in the base classes
+of your choosing get called. Explicitly calling DESTROY is also possible,
+but is usually never needed.
+
+DESTROY is subject to AUTOLOAD lookup, just like any other method. Hence, if
+your class has an AUTOLOAD method, but does not need any DESTROY actions,
+you probably want to provide a DESTROY method anyway, to prevent an
+expensive call to AUTOLOAD each time an object is freed. As this technique
+makes empty DESTROY methods common, the implementation is optimised so that
+a DESTROY method that is an empty or constant subroutine, and hence could
+have no side effects anyway, is not actually called.
+X<AUTOLOAD> X<DESTROY>
+
+Do not confuse the previous discussion with how objects I<CONTAINED> in the current
+one are destroyed. Such objects will be freed and destroyed automatically
+when the current object is freed, provided no other references to them exist
+elsewhere.
+
+=head2 Summary
+
+That's about all there is to it. Now you need just to go off and buy a
+book about object-oriented design methodology, and bang your forehead
+with it for the next six months or so.
+
+=head2 Two-Phased Garbage Collection
+X<garbage collection> X<GC> X<circular reference>
+X<reference, circular> X<DESTROY> X<destructor>
+
+For most purposes, Perl uses a fast and simple, reference-based
+garbage collection system. That means there's an extra
+dereference going on at some level, so if you haven't built
+your Perl executable using your C compiler's C<-O> flag, performance
+will suffer. If you I<have> built Perl with C<cc -O>, then this
+probably won't matter.
+
+A more serious concern is that unreachable memory with a non-zero
+reference count will not normally get freed. Therefore, this is a bad
+idea:
+
+ {
+ my $a;
+ $a = \$a;
+ }
+
+Even thought $a I<should> go away, it can't. When building recursive data
+structures, you'll have to break the self-reference yourself explicitly
+if you don't care to leak. For example, here's a self-referential
+node such as one might use in a sophisticated tree structure:
+
+ sub new_node {
+ my $class = shift;
+ my $node = {};
+ $node->{LEFT} = $node->{RIGHT} = $node;
+ $node->{DATA} = [ @_ ];
+ return bless $node => $class;
+ }
+
+If you create nodes like that, they (currently) won't go away unless you
+break their self reference yourself. (In other words, this is not to be
+construed as a feature, and you shouldn't depend on it.)
+
+Almost.
+
+When an interpreter thread finally shuts down (usually when your program
+exits), then a rather costly but complete mark-and-sweep style of garbage
+collection is performed, and everything allocated by that thread gets
+destroyed. This is essential to support Perl as an embedded or a
+multithreadable language. For example, this program demonstrates Perl's
+two-phased garbage collection:
+
+ #!/usr/bin/perl
+ package Subtle;
+
+ sub new {
+ my $test;
+ $test = \$test;
+ warn "CREATING " . \$test;
+ return bless \$test;
+ }
+
+ sub DESTROY {
+ my $self = shift;
+ warn "DESTROYING $self";
+ }
+
+ package main;
+
+ warn "starting program";
+ {
+ my $a = Subtle->new;
+ my $b = Subtle->new;
+ $$a = 0; # break selfref
+ warn "leaving block";
+ }
+
+ warn "just exited block";
+ warn "time to die...";
+ exit;
+
+When run as F</foo/test>, the following output is produced:
+
+ starting program at /foo/test line 18.
+ CREATING SCALAR(0x8e5b8) at /foo/test line 7.
+ CREATING SCALAR(0x8e57c) at /foo/test line 7.
+ leaving block at /foo/test line 23.
+ DESTROYING Subtle=SCALAR(0x8e5b8) at /foo/test line 13.
+ just exited block at /foo/test line 26.
+ time to die... at /foo/test line 27.
+ DESTROYING Subtle=SCALAR(0x8e57c) during global destruction.
+
+Notice that "global destruction" bit there? That's the thread
+garbage collector reaching the unreachable.
+
+Objects are always destructed, even when regular refs aren't. Objects
+are destructed in a separate pass before ordinary refs just to
+prevent object destructors from using refs that have been themselves
+destructed. Plain refs are only garbage-collected if the destruct level
+is greater than 0. You can test the higher levels of global destruction
+by setting the PERL_DESTRUCT_LEVEL environment variable, presuming
+C<-DDEBUGGING> was enabled during perl build time.
+See L<perlhack/PERL_DESTRUCT_LEVEL> for more information.
+
+A more complete garbage collection strategy will be implemented
+at a future date.
+
+In the meantime, the best solution is to create a non-recursive container
+class that holds a pointer to the self-referential data structure.
+Define a DESTROY method for the containing object's class that manually
+breaks the circularities in the self-referential structure.
+
+=head1 SEE ALSO
+
+A kinder, gentler tutorial on object-oriented programming in Perl can
+be found in L<perltoot>, L<perlboot> and L<perltooc>. You should
+also check out L<perlbot> for other object tricks, traps, and tips, as
+well as L<perlmodlib> for some style guides on constructing both
+modules and classes.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlop.pod b/Master/tlpkg/tlperl/lib/pods/perlop.pod
new file mode 100644
index 00000000000..ebe32fb3102
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlop.pod
@@ -0,0 +1,2586 @@
+=head1 NAME
+X<operator>
+
+perlop - Perl operators and precedence
+
+=head1 DESCRIPTION
+
+=head2 Operator Precedence and Associativity
+X<operator, precedence> X<precedence> X<associativity>
+
+Operator precedence and associativity work in Perl more or less like
+they do in mathematics.
+
+I<Operator precedence> means some operators are evaluated before
+others. For example, in C<2 + 4 * 5>, the multiplication has higher
+precedence so C<4 * 5> is evaluated first yielding C<2 + 20 ==
+22> and not C<6 * 5 == 30>.
+
+I<Operator associativity> defines what happens if a sequence of the
+same operators is used one after another: whether the evaluator will
+evaluate the left operations first or the right. For example, in C<8
+- 4 - 2>, subtraction is left associative so Perl evaluates the
+expression left to right. C<8 - 4> is evaluated first making the
+expression C<4 - 2 == 2> and not C<8 - 2 == 6>.
+
+Perl operators have the following associativity and precedence,
+listed from highest precedence to lowest. Operators borrowed from
+C keep the same precedence relationship with each other, even where
+C's precedence is slightly screwy. (This makes learning Perl easier
+for C folks.) With very few exceptions, these all operate on scalar
+values only, not array values.
+
+ left terms and list operators (leftward)
+ left ->
+ nonassoc ++ --
+ right **
+ right ! ~ \ and unary + and -
+ left =~ !~
+ left * / % x
+ left + - .
+ left << >>
+ nonassoc named unary operators
+ nonassoc < > <= >= lt gt le ge
+ nonassoc == != <=> eq ne cmp ~~
+ left &
+ left | ^
+ left &&
+ left || //
+ nonassoc .. ...
+ right ?:
+ right = += -= *= etc.
+ left , =>
+ nonassoc list operators (rightward)
+ right not
+ left and
+ left or xor
+
+In the following sections, these operators are covered in precedence order.
+
+Many operators can be overloaded for objects. See L<overload>.
+
+=head2 Terms and List Operators (Leftward)
+X<list operator> X<operator, list> X<term>
+
+A TERM has the highest precedence in Perl. They include variables,
+quote and quote-like operators, any expression in parentheses,
+and any function whose arguments are parenthesized. Actually, there
+aren't really functions in this sense, just list operators and unary
+operators behaving as functions because you put parentheses around
+the arguments. These are all documented in L<perlfunc>.
+
+If any list operator (print(), etc.) or any unary operator (chdir(), etc.)
+is followed by a left parenthesis as the next token, the operator and
+arguments within parentheses are taken to be of highest precedence,
+just like a normal function call.
+
+In the absence of parentheses, the precedence of list operators such as
+C<print>, C<sort>, or C<chmod> is either very high or very low depending on
+whether you are looking at the left side or the right side of the operator.
+For example, in
+
+ @ary = (1, 3, sort 4, 2);
+ print @ary; # prints 1324
+
+the commas on the right of the sort are evaluated before the sort,
+but the commas on the left are evaluated after. In other words,
+list operators tend to gobble up all arguments that follow, and
+then act like a simple TERM with regard to the preceding expression.
+Be careful with parentheses:
+
+ # These evaluate exit before doing the print:
+ print($foo, exit); # Obviously not what you want.
+ print $foo, exit; # Nor is this.
+
+ # These do the print before evaluating exit:
+ (print $foo), exit; # This is what you want.
+ print($foo), exit; # Or this.
+ print ($foo), exit; # Or even this.
+
+Also note that
+
+ print ($foo & 255) + 1, "\n";
+
+probably doesn't do what you expect at first glance. The parentheses
+enclose the argument list for C<print> which is evaluated (printing
+the result of C<$foo & 255>). Then one is added to the return value
+of C<print> (usually 1). The result is something like this:
+
+ 1 + 1, "\n"; # Obviously not what you meant.
+
+To do what you meant properly, you must write:
+
+ print(($foo & 255) + 1, "\n");
+
+See L<Named Unary Operators> for more discussion of this.
+
+Also parsed as terms are the C<do {}> and C<eval {}> constructs, as
+well as subroutine and method calls, and the anonymous
+constructors C<[]> and C<{}>.
+
+See also L<Quote and Quote-like Operators> toward the end of this section,
+as well as L</"I/O Operators">.
+
+=head2 The Arrow Operator
+X<arrow> X<dereference> X<< -> >>
+
+"C<< -> >>" is an infix dereference operator, just as it is in C
+and C++. If the right side is either a C<[...]>, C<{...}>, or a
+C<(...)> subscript, then the left side must be either a hard or
+symbolic reference to an array, a hash, or a subroutine respectively.
+(Or technically speaking, a location capable of holding a hard
+reference, if it's an array or hash reference being used for
+assignment.) See L<perlreftut> and L<perlref>.
+
+Otherwise, the right side is a method name or a simple scalar
+variable containing either the method name or a subroutine reference,
+and the left side must be either an object (a blessed reference)
+or a class name (that is, a package name). See L<perlobj>.
+
+=head2 Auto-increment and Auto-decrement
+X<increment> X<auto-increment> X<++> X<decrement> X<auto-decrement> X<-->
+
+"++" and "--" work as in C. That is, if placed before a variable,
+they increment or decrement the variable by one before returning the
+value, and if placed after, increment or decrement after returning the
+value.
+
+ $i = 0; $j = 0;
+ print $i++; # prints 0
+ print ++$j; # prints 1
+
+Note that just as in C, Perl doesn't define B<when> the variable is
+incremented or decremented. You just know it will be done sometime
+before or after the value is returned. This also means that modifying
+a variable twice in the same statement will lead to undefined behaviour.
+Avoid statements like:
+
+ $i = $i ++;
+ print ++ $i + $i ++;
+
+Perl will not guarantee what the result of the above statements is.
+
+The auto-increment operator has a little extra builtin magic to it. If
+you increment a variable that is numeric, or that has ever been used in
+a numeric context, you get a normal increment. If, however, the
+variable has been used in only string contexts since it was set, and
+has a value that is not the empty string and matches the pattern
+C</^[a-zA-Z]*[0-9]*\z/>, the increment is done as a string, preserving each
+character within its range, with carry:
+
+ print ++($foo = '99'); # prints '100'
+ print ++($foo = 'a0'); # prints 'a1'
+ print ++($foo = 'Az'); # prints 'Ba'
+ print ++($foo = 'zz'); # prints 'aaa'
+
+C<undef> is always treated as numeric, and in particular is changed
+to C<0> before incrementing (so that a post-increment of an undef value
+will return C<0> rather than C<undef>).
+
+The auto-decrement operator is not magical.
+
+=head2 Exponentiation
+X<**> X<exponentiation> X<power>
+
+Binary "**" is the exponentiation operator. It binds even more
+tightly than unary minus, so -2**4 is -(2**4), not (-2)**4. (This is
+implemented using C's pow(3) function, which actually works on doubles
+internally.)
+
+=head2 Symbolic Unary Operators
+X<unary operator> X<operator, unary>
+
+Unary "!" performs logical negation, i.e., "not". See also C<not> for a lower
+precedence version of this.
+X<!>
+
+Unary "-" performs arithmetic negation if the operand is numeric. If
+the operand is an identifier, a string consisting of a minus sign
+concatenated with the identifier is returned. Otherwise, if the string
+starts with a plus or minus, a string starting with the opposite sign
+is returned. One effect of these rules is that -bareword is equivalent
+to the string "-bareword". If, however, the string begins with a
+non-alphabetic character (excluding "+" or "-"), Perl will attempt to convert
+the string to a numeric and the arithmetic negation is performed. If the
+string cannot be cleanly converted to a numeric, Perl will give the warning
+B<Argument "the string" isn't numeric in negation (-) at ...>.
+X<-> X<negation, arithmetic>
+
+Unary "~" performs bitwise negation, i.e., 1's complement. For
+example, C<0666 & ~027> is 0640. (See also L<Integer Arithmetic> and
+L<Bitwise String Operators>.) Note that the width of the result is
+platform-dependent: ~0 is 32 bits wide on a 32-bit platform, but 64
+bits wide on a 64-bit platform, so if you are expecting a certain bit
+width, remember to use the & operator to mask off the excess bits.
+X<~> X<negation, binary>
+
+Unary "+" has no effect whatsoever, even on strings. It is useful
+syntactically for separating a function name from a parenthesized expression
+that would otherwise be interpreted as the complete list of function
+arguments. (See examples above under L<Terms and List Operators (Leftward)>.)
+X<+>
+
+Unary "\" creates a reference to whatever follows it. See L<perlreftut>
+and L<perlref>. Do not confuse this behavior with the behavior of
+backslash within a string, although both forms do convey the notion
+of protecting the next thing from interpolation.
+X<\> X<reference> X<backslash>
+
+=head2 Binding Operators
+X<binding> X<operator, binding> X<=~> X<!~>
+
+Binary "=~" binds a scalar expression to a pattern match. Certain operations
+search or modify the string $_ by default. This operator makes that kind
+of operation work on some other string. The right argument is a search
+pattern, substitution, or transliteration. The left argument is what is
+supposed to be searched, substituted, or transliterated instead of the default
+$_. When used in scalar context, the return value generally indicates the
+success of the operation. Behavior in list context depends on the particular
+operator. See L</"Regexp Quote-Like Operators"> for details and
+L<perlretut> for examples using these operators.
+
+If the right argument is an expression rather than a search pattern,
+substitution, or transliteration, it is interpreted as a search pattern at run
+time. Note that this means that its contents will be interpolated twice, so
+
+ '\\' =~ q'\\';
+
+is not ok, as the regex engine will end up trying to compile the
+pattern C<\>, which it will consider a syntax error.
+
+Binary "!~" is just like "=~" except the return value is negated in
+the logical sense.
+
+=head2 Multiplicative Operators
+X<operator, multiplicative>
+
+Binary "*" multiplies two numbers.
+X<*>
+
+Binary "/" divides two numbers.
+X</> X<slash>
+
+Binary "%" is the modulo operator, which computes the division
+remainder of its first argument with respect to its second argument.
+Given integer
+operands C<$a> and C<$b>: If C<$b> is positive, then C<$a % $b> is
+C<$a> minus the largest multiple of C<$b> less than or equal to
+C<$a>. If C<$b> is negative, then C<$a % $b> is C<$a> minus the
+smallest multiple of C<$b> that is not less than C<$a> (i.e. the
+result will be less than or equal to zero). If the operands
+C<$a> and C<$b> are floating point values and the absolute value of
+C<$b> (that is C<abs($b)>) is less than C<(UV_MAX + 1)>, only
+the integer portion of C<$a> and C<$b> will be used in the operation
+(Note: here C<UV_MAX> means the maximum of the unsigned integer type).
+If the absolute value of the right operand (C<abs($b)>) is greater than
+or equal to C<(UV_MAX + 1)>, "%" computes the floating-point remainder
+C<$r> in the equation C<($r = $a - $i*$b)> where C<$i> is a certain
+integer that makes C<$r> have the same sign as the right operand
+C<$b> (B<not> as the left operand C<$a> like C function C<fmod()>)
+and the absolute value less than that of C<$b>.
+Note that when C<use integer> is in scope, "%" gives you direct access
+to the modulo operator as implemented by your C compiler. This
+operator is not as well defined for negative operands, but it will
+execute faster.
+X<%> X<remainder> X<modulo> X<mod>
+
+Binary "x" is the repetition operator. In scalar context or if the left
+operand is not enclosed in parentheses, it returns a string consisting
+of the left operand repeated the number of times specified by the right
+operand. In list context, if the left operand is enclosed in
+parentheses or is a list formed by C<qw/STRING/>, it repeats the list.
+If the right operand is zero or negative, it returns an empty string
+or an empty list, depending on the context.
+X<x>
+
+ print '-' x 80; # print row of dashes
+
+ print "\t" x ($tab/8), ' ' x ($tab%8); # tab over
+
+ @ones = (1) x 80; # a list of 80 1's
+ @ones = (5) x @ones; # set all elements to 5
+
+
+=head2 Additive Operators
+X<operator, additive>
+
+Binary "+" returns the sum of two numbers.
+X<+>
+
+Binary "-" returns the difference of two numbers.
+X<->
+
+Binary "." concatenates two strings.
+X<string, concatenation> X<concatenation>
+X<cat> X<concat> X<concatenate> X<.>
+
+=head2 Shift Operators
+X<shift operator> X<operator, shift> X<<< << >>>
+X<<< >> >>> X<right shift> X<left shift> X<bitwise shift>
+X<shl> X<shr> X<shift, right> X<shift, left>
+
+Binary "<<" returns the value of its left argument shifted left by the
+number of bits specified by the right argument. Arguments should be
+integers. (See also L<Integer Arithmetic>.)
+
+Binary ">>" returns the value of its left argument shifted right by
+the number of bits specified by the right argument. Arguments should
+be integers. (See also L<Integer Arithmetic>.)
+
+Note that both "<<" and ">>" in Perl are implemented directly using
+"<<" and ">>" in C. If C<use integer> (see L<Integer Arithmetic>) is
+in force then signed C integers are used, else unsigned C integers are
+used. Either way, the implementation isn't going to generate results
+larger than the size of the integer type Perl was built with (32 bits
+or 64 bits).
+
+The result of overflowing the range of the integers is undefined
+because it is undefined also in C. In other words, using 32-bit
+integers, C<< 1 << 32 >> is undefined. Shifting by a negative number
+of bits is also undefined.
+
+=head2 Named Unary Operators
+X<operator, named unary>
+
+The various named unary operators are treated as functions with one
+argument, with optional parentheses.
+
+If any list operator (print(), etc.) or any unary operator (chdir(), etc.)
+is followed by a left parenthesis as the next token, the operator and
+arguments within parentheses are taken to be of highest precedence,
+just like a normal function call. For example,
+because named unary operators are higher precedence than ||:
+
+ chdir $foo || die; # (chdir $foo) || die
+ chdir($foo) || die; # (chdir $foo) || die
+ chdir ($foo) || die; # (chdir $foo) || die
+ chdir +($foo) || die; # (chdir $foo) || die
+
+but, because * is higher precedence than named operators:
+
+ chdir $foo * 20; # chdir ($foo * 20)
+ chdir($foo) * 20; # (chdir $foo) * 20
+ chdir ($foo) * 20; # (chdir $foo) * 20
+ chdir +($foo) * 20; # chdir ($foo * 20)
+
+ rand 10 * 20; # rand (10 * 20)
+ rand(10) * 20; # (rand 10) * 20
+ rand (10) * 20; # (rand 10) * 20
+ rand +(10) * 20; # rand (10 * 20)
+
+Regarding precedence, the filetest operators, like C<-f>, C<-M>, etc. are
+treated like named unary operators, but they don't follow this functional
+parenthesis rule. That means, for example, that C<-f($file).".bak"> is
+equivalent to C<-f "$file.bak">.
+X<-X> X<filetest> X<operator, filetest>
+
+See also L<"Terms and List Operators (Leftward)">.
+
+=head2 Relational Operators
+X<relational operator> X<operator, relational>
+
+Binary "<" returns true if the left argument is numerically less than
+the right argument.
+X<< < >>
+
+Binary ">" returns true if the left argument is numerically greater
+than the right argument.
+X<< > >>
+
+Binary "<=" returns true if the left argument is numerically less than
+or equal to the right argument.
+X<< <= >>
+
+Binary ">=" returns true if the left argument is numerically greater
+than or equal to the right argument.
+X<< >= >>
+
+Binary "lt" returns true if the left argument is stringwise less than
+the right argument.
+X<< lt >>
+
+Binary "gt" returns true if the left argument is stringwise greater
+than the right argument.
+X<< gt >>
+
+Binary "le" returns true if the left argument is stringwise less than
+or equal to the right argument.
+X<< le >>
+
+Binary "ge" returns true if the left argument is stringwise greater
+than or equal to the right argument.
+X<< ge >>
+
+=head2 Equality Operators
+X<equality> X<equal> X<equals> X<operator, equality>
+
+Binary "==" returns true if the left argument is numerically equal to
+the right argument.
+X<==>
+
+Binary "!=" returns true if the left argument is numerically not equal
+to the right argument.
+X<!=>
+
+Binary "<=>" returns -1, 0, or 1 depending on whether the left
+argument is numerically less than, equal to, or greater than the right
+argument. If your platform supports NaNs (not-a-numbers) as numeric
+values, using them with "<=>" returns undef. NaN is not "<", "==", ">",
+"<=" or ">=" anything (even NaN), so those 5 return false. NaN != NaN
+returns true, as does NaN != anything else. If your platform doesn't
+support NaNs then NaN is just a string with numeric value 0.
+X<< <=> >> X<spaceship>
+
+ perl -le '$a = "NaN"; print "No NaN support here" if $a == $a'
+ perl -le '$a = "NaN"; print "NaN support here" if $a != $a'
+
+Binary "eq" returns true if the left argument is stringwise equal to
+the right argument.
+X<eq>
+
+Binary "ne" returns true if the left argument is stringwise not equal
+to the right argument.
+X<ne>
+
+Binary "cmp" returns -1, 0, or 1 depending on whether the left
+argument is stringwise less than, equal to, or greater than the right
+argument.
+X<cmp>
+
+Binary "~~" does a smart match between its arguments. Smart matching
+is described in L<perlsyn/"Smart matching in detail">.
+X<~~>
+
+"lt", "le", "ge", "gt" and "cmp" use the collation (sort) order specified
+by the current locale if C<use locale> is in effect. See L<perllocale>.
+
+=head2 Bitwise And
+X<operator, bitwise, and> X<bitwise and> X<&>
+
+Binary "&" returns its operands ANDed together bit by bit.
+(See also L<Integer Arithmetic> and L<Bitwise String Operators>.)
+
+Note that "&" has lower priority than relational operators, so for example
+the brackets are essential in a test like
+
+ print "Even\n" if ($x & 1) == 0;
+
+=head2 Bitwise Or and Exclusive Or
+X<operator, bitwise, or> X<bitwise or> X<|> X<operator, bitwise, xor>
+X<bitwise xor> X<^>
+
+Binary "|" returns its operands ORed together bit by bit.
+(See also L<Integer Arithmetic> and L<Bitwise String Operators>.)
+
+Binary "^" returns its operands XORed together bit by bit.
+(See also L<Integer Arithmetic> and L<Bitwise String Operators>.)
+
+Note that "|" and "^" have lower priority than relational operators, so
+for example the brackets are essential in a test like
+
+ print "false\n" if (8 | 2) != 10;
+
+=head2 C-style Logical And
+X<&&> X<logical and> X<operator, logical, and>
+
+Binary "&&" performs a short-circuit logical AND operation. That is,
+if the left operand is false, the right operand is not even evaluated.
+Scalar or list context propagates down to the right operand if it
+is evaluated.
+
+=head2 C-style Logical Or
+X<||> X<operator, logical, or>
+
+Binary "||" performs a short-circuit logical OR operation. That is,
+if the left operand is true, the right operand is not even evaluated.
+Scalar or list context propagates down to the right operand if it
+is evaluated.
+
+=head2 C-style Logical Defined-Or
+X<//> X<operator, logical, defined-or>
+
+Although it has no direct equivalent in C, Perl's C<//> operator is related
+to its C-style or. In fact, it's exactly the same as C<||>, except that it
+tests the left hand side's definedness instead of its truth. Thus, C<$a // $b>
+is similar to C<defined($a) || $b> (except that it returns the value of C<$a>
+rather than the value of C<defined($a)>) and is exactly equivalent to
+C<defined($a) ? $a : $b>. This is very useful for providing default values
+for variables. If you actually want to test if at least one of C<$a> and
+C<$b> is defined, use C<defined($a // $b)>.
+
+The C<||>, C<//> and C<&&> operators return the last value evaluated
+(unlike C's C<||> and C<&&>, which return 0 or 1). Thus, a reasonably
+portable way to find out the home directory might be:
+
+ $home = $ENV{'HOME'} // $ENV{'LOGDIR'} //
+ (getpwuid($<))[7] // die "You're homeless!\n";
+
+In particular, this means that you shouldn't use this
+for selecting between two aggregates for assignment:
+
+ @a = @b || @c; # this is wrong
+ @a = scalar(@b) || @c; # really meant this
+ @a = @b ? @b : @c; # this works fine, though
+
+As more readable alternatives to C<&&> and C<||> when used for
+control flow, Perl provides the C<and> and C<or> operators (see below).
+The short-circuit behavior is identical. The precedence of "and"
+and "or" is much lower, however, so that you can safely use them after a
+list operator without the need for parentheses:
+
+ unlink "alpha", "beta", "gamma"
+ or gripe(), next LINE;
+
+With the C-style operators that would have been written like this:
+
+ unlink("alpha", "beta", "gamma")
+ || (gripe(), next LINE);
+
+Using "or" for assignment is unlikely to do what you want; see below.
+
+=head2 Range Operators
+X<operator, range> X<range> X<..> X<...>
+
+Binary ".." is the range operator, which is really two different
+operators depending on the context. In list context, it returns a
+list of values counting (up by ones) from the left value to the right
+value. If the left value is greater than the right value then it
+returns the empty list. The range operator is useful for writing
+C<foreach (1..10)> loops and for doing slice operations on arrays. In
+the current implementation, no temporary array is created when the
+range operator is used as the expression in C<foreach> loops, but older
+versions of Perl might burn a lot of memory when you write something
+like this:
+
+ for (1 .. 1_000_000) {
+ # code
+ }
+
+The range operator also works on strings, using the magical
+auto-increment, see below.
+
+In scalar context, ".." returns a boolean value. The operator is
+bistable, like a flip-flop, and emulates the line-range (comma)
+operator of B<sed>, B<awk>, and various editors. Each ".." operator
+maintains its own boolean state, even across calls to a subroutine
+that contains it. It is false as long as its left operand is false.
+Once the left operand is true, the range operator stays true until the
+right operand is true, I<AFTER> which the range operator becomes false
+again. It doesn't become false till the next time the range operator
+is evaluated. It can test the right operand and become false on the
+same evaluation it became true (as in B<awk>), but it still returns
+true once. If you don't want it to test the right operand until the
+next evaluation, as in B<sed>, just use three dots ("...") instead of
+two. In all other regards, "..." behaves just like ".." does.
+
+The right operand is not evaluated while the operator is in the
+"false" state, and the left operand is not evaluated while the
+operator is in the "true" state. The precedence is a little lower
+than || and &&. The value returned is either the empty string for
+false, or a sequence number (beginning with 1) for true. The sequence
+number is reset for each range encountered. The final sequence number
+in a range has the string "E0" appended to it, which doesn't affect
+its numeric value, but gives you something to search for if you want
+to exclude the endpoint. You can exclude the beginning point by
+waiting for the sequence number to be greater than 1.
+
+If either operand of scalar ".." is a constant expression,
+that operand is considered true if it is equal (C<==>) to the current
+input line number (the C<$.> variable).
+
+To be pedantic, the comparison is actually C<int(EXPR) == int(EXPR)>,
+but that is only an issue if you use a floating point expression; when
+implicitly using C<$.> as described in the previous paragraph, the
+comparison is C<int(EXPR) == int($.)> which is only an issue when C<$.>
+is set to a floating point value and you are not reading from a file.
+Furthermore, C<"span" .. "spat"> or C<2.18 .. 3.14> will not do what
+you want in scalar context because each of the operands are evaluated
+using their integer representation.
+
+Examples:
+
+As a scalar operator:
+
+ if (101 .. 200) { print; } # print 2nd hundred lines, short for
+ # if ($. == 101 .. $. == 200) { print; }
+
+ next LINE if (1 .. /^$/); # skip header lines, short for
+ # next LINE if ($. == 1 .. /^$/);
+ # (typically in a loop labeled LINE)
+
+ s/^/> / if (/^$/ .. eof()); # quote body
+
+ # parse mail messages
+ while (<>) {
+ $in_header = 1 .. /^$/;
+ $in_body = /^$/ .. eof;
+ if ($in_header) {
+ # do something
+ } else { # in body
+ # do something else
+ }
+ } continue {
+ close ARGV if eof; # reset $. each file
+ }
+
+Here's a simple example to illustrate the difference between
+the two range operators:
+
+ @lines = (" - Foo",
+ "01 - Bar",
+ "1 - Baz",
+ " - Quux");
+
+ foreach (@lines) {
+ if (/0/ .. /1/) {
+ print "$_\n";
+ }
+ }
+
+This program will print only the line containing "Bar". If
+the range operator is changed to C<...>, it will also print the
+"Baz" line.
+
+And now some examples as a list operator:
+
+ for (101 .. 200) { print; } # print $_ 100 times
+ @foo = @foo[0 .. $#foo]; # an expensive no-op
+ @foo = @foo[$#foo-4 .. $#foo]; # slice last 5 items
+
+The range operator (in list context) makes use of the magical
+auto-increment algorithm if the operands are strings. You
+can say
+
+ @alphabet = ('A' .. 'Z');
+
+to get all normal letters of the English alphabet, or
+
+ $hexdigit = (0 .. 9, 'a' .. 'f')[$num & 15];
+
+to get a hexadecimal digit, or
+
+ @z2 = ('01' .. '31'); print $z2[$mday];
+
+to get dates with leading zeros.
+
+If the final value specified is not in the sequence that the magical
+increment would produce, the sequence goes until the next value would
+be longer than the final value specified.
+
+If the initial value specified isn't part of a magical increment
+sequence (that is, a non-empty string matching "/^[a-zA-Z]*[0-9]*\z/"),
+only the initial value will be returned. So the following will only
+return an alpha:
+
+ use charnames 'greek';
+ my @greek_small = ("\N{alpha}" .. "\N{omega}");
+
+To get lower-case greek letters, use this instead:
+
+ my @greek_small = map { chr } ( ord("\N{alpha}") .. ord("\N{omega}") );
+
+Because each operand is evaluated in integer form, C<2.18 .. 3.14> will
+return two elements in list context.
+
+ @list = (2.18 .. 3.14); # same as @list = (2 .. 3);
+
+=head2 Conditional Operator
+X<operator, conditional> X<operator, ternary> X<ternary> X<?:>
+
+Ternary "?:" is the conditional operator, just as in C. It works much
+like an if-then-else. If the argument before the ? is true, the
+argument before the : is returned, otherwise the argument after the :
+is returned. For example:
+
+ printf "I have %d dog%s.\n", $n,
+ ($n == 1) ? '' : "s";
+
+Scalar or list context propagates downward into the 2nd
+or 3rd argument, whichever is selected.
+
+ $a = $ok ? $b : $c; # get a scalar
+ @a = $ok ? @b : @c; # get an array
+ $a = $ok ? @b : @c; # oops, that's just a count!
+
+The operator may be assigned to if both the 2nd and 3rd arguments are
+legal lvalues (meaning that you can assign to them):
+
+ ($a_or_b ? $a : $b) = $c;
+
+Because this operator produces an assignable result, using assignments
+without parentheses will get you in trouble. For example, this:
+
+ $a % 2 ? $a += 10 : $a += 2
+
+Really means this:
+
+ (($a % 2) ? ($a += 10) : $a) += 2
+
+Rather than this:
+
+ ($a % 2) ? ($a += 10) : ($a += 2)
+
+That should probably be written more simply as:
+
+ $a += ($a % 2) ? 10 : 2;
+
+=head2 Assignment Operators
+X<assignment> X<operator, assignment> X<=> X<**=> X<+=> X<*=> X<&=>
+X<<< <<= >>> X<&&=> X<-=> X</=> X<|=> X<<< >>= >>> X<||=> X<//=> X<.=>
+X<%=> X<^=> X<x=>
+
+"=" is the ordinary assignment operator.
+
+Assignment operators work as in C. That is,
+
+ $a += 2;
+
+is equivalent to
+
+ $a = $a + 2;
+
+although without duplicating any side effects that dereferencing the lvalue
+might trigger, such as from tie(). Other assignment operators work similarly.
+The following are recognized:
+
+ **= += *= &= <<= &&=
+ -= /= |= >>= ||=
+ .= %= ^= //=
+ x=
+
+Although these are grouped by family, they all have the precedence
+of assignment.
+
+Unlike in C, the scalar assignment operator produces a valid lvalue.
+Modifying an assignment is equivalent to doing the assignment and
+then modifying the variable that was assigned to. This is useful
+for modifying a copy of something, like this:
+
+ ($tmp = $global) =~ tr [A-Z] [a-z];
+
+Likewise,
+
+ ($a += 2) *= 3;
+
+is equivalent to
+
+ $a += 2;
+ $a *= 3;
+
+Similarly, a list assignment in list context produces the list of
+lvalues assigned to, and a list assignment in scalar context returns
+the number of elements produced by the expression on the right hand
+side of the assignment.
+
+=head2 Comma Operator
+X<comma> X<operator, comma> X<,>
+
+Binary "," is the comma operator. In scalar context it evaluates
+its left argument, throws that value away, then evaluates its right
+argument and returns that value. This is just like C's comma operator.
+
+In list context, it's just the list argument separator, and inserts
+both its arguments into the list. These arguments are also evaluated
+from left to right.
+
+The C<< => >> operator is a synonym for the comma except that it causes
+its left operand to be interpreted as a string if it begins with a letter
+or underscore and is composed only of letters, digits and underscores.
+This includes operands that might otherwise be interpreted as operators,
+constants, single number v-strings or function calls. If in doubt about
+this behaviour, the left operand can be quoted explicitly.
+
+Otherwise, the C<< => >> operator behaves exactly as the comma operator
+or list argument separator, according to context.
+
+For example:
+
+ use constant FOO => "something";
+
+ my %h = ( FOO => 23 );
+
+is equivalent to:
+
+ my %h = ("FOO", 23);
+
+It is I<NOT>:
+
+ my %h = ("something", 23);
+
+The C<< => >> operator is helpful in documenting the correspondence
+between keys and values in hashes, and other paired elements in lists.
+
+ %hash = ( $key => $value );
+ login( $username => $password );
+
+=head2 Yada Yada Operator
+X<...> X<... operator> X<yada yada operator>
+
+The yada yada operator (noted C<...>) is a placeholder for code. Perl
+parses it without error, but when you try to execute a yada yada, it
+throws an exception with the text C<Unimplemented>:
+
+ sub unimplemented { ... }
+
+ eval { unimplemented() };
+ if( $@ eq 'Unimplemented' ) {
+ print "I found the yada yada!\n";
+ }
+
+You can only use the yada yada to stand in for a complete statement.
+These examples of the yada yada work:
+
+ { ... }
+
+ sub foo { ... }
+
+ ...;
+
+ eval { ... };
+
+ sub foo {
+ my( $self ) = shift;
+
+ ...;
+ }
+
+ do { my $n; ...; print 'Hurrah!' };
+
+The yada yada cannot stand in for an expression that is part of a
+larger statement since the C<...> is also the three-dot version of the
+range operator (see L<Range Operators>). These examples of the yada
+yada are still syntax errors:
+
+ print ...;
+
+ open my($fh), '>', '/dev/passwd' or ...;
+
+ if( $condition && ... ) { print "Hello\n" };
+
+There are some cases where Perl can't immediately tell the difference
+between an expression and a statement. For instance, the syntax for a
+block and an anonymous hash reference constructor look the same unless
+there's something in the braces that give Perl a hint. The yada yada
+is a syntax error if Perl doesn't guess that the C<{ ... }> is a
+block. In that case, it doesn't think the C<...> is the yada yada
+because it's expecting an expression instead of a statement:
+
+ my @transformed = map { ... } @input; # syntax error
+
+You can use a C<;> inside your block to denote that the C<{ ... }> is
+a block and not a hash reference constructor. Now the yada yada works:
+
+ my @transformed = map {; ... } @input; # ; disambiguates
+
+ my @transformed = map { ...; } @input; # ; disambiguates
+
+=head2 List Operators (Rightward)
+X<operator, list, rightward> X<list operator>
+
+On the right side of a list operator, it has very low precedence,
+such that it controls all comma-separated expressions found there.
+The only operators with lower precedence are the logical operators
+"and", "or", and "not", which may be used to evaluate calls to list
+operators without the need for extra parentheses:
+
+ open HANDLE, "filename"
+ or die "Can't open: $!\n";
+
+See also discussion of list operators in L<Terms and List Operators (Leftward)>.
+
+=head2 Logical Not
+X<operator, logical, not> X<not>
+
+Unary "not" returns the logical negation of the expression to its right.
+It's the equivalent of "!" except for the very low precedence.
+
+=head2 Logical And
+X<operator, logical, and> X<and>
+
+Binary "and" returns the logical conjunction of the two surrounding
+expressions. It's equivalent to && except for the very low
+precedence. This means that it short-circuits: i.e., the right
+expression is evaluated only if the left expression is true.
+
+=head2 Logical or, Defined or, and Exclusive Or
+X<operator, logical, or> X<operator, logical, xor>
+X<operator, logical, defined or> X<operator, logical, exclusive or>
+X<or> X<xor>
+
+Binary "or" returns the logical disjunction of the two surrounding
+expressions. It's equivalent to || except for the very low precedence.
+This makes it useful for control flow
+
+ print FH $data or die "Can't write to FH: $!";
+
+This means that it short-circuits: i.e., the right expression is evaluated
+only if the left expression is false. Due to its precedence, you should
+probably avoid using this for assignment, only for control flow.
+
+ $a = $b or $c; # bug: this is wrong
+ ($a = $b) or $c; # really means this
+ $a = $b || $c; # better written this way
+
+However, when it's a list-context assignment and you're trying to use
+"||" for control flow, you probably need "or" so that the assignment
+takes higher precedence.
+
+ @info = stat($file) || die; # oops, scalar sense of stat!
+ @info = stat($file) or die; # better, now @info gets its due
+
+Then again, you could always use parentheses.
+
+Binary "xor" returns the exclusive-OR of the two surrounding expressions.
+It cannot short circuit, of course.
+
+=head2 C Operators Missing From Perl
+X<operator, missing from perl> X<&> X<*>
+X<typecasting> X<(TYPE)>
+
+Here is what C has that Perl doesn't:
+
+=over 8
+
+=item unary &
+
+Address-of operator. (But see the "\" operator for taking a reference.)
+
+=item unary *
+
+Dereference-address operator. (Perl's prefix dereferencing
+operators are typed: $, @, %, and &.)
+
+=item (TYPE)
+
+Type-casting operator.
+
+=back
+
+=head2 Quote and Quote-like Operators
+X<operator, quote> X<operator, quote-like> X<q> X<qq> X<qx> X<qw> X<m>
+X<qr> X<s> X<tr> X<'> X<''> X<"> X<""> X<//> X<`> X<``> X<<< << >>>
+X<escape sequence> X<escape>
+
+
+While we usually think of quotes as literal values, in Perl they
+function as operators, providing various kinds of interpolating and
+pattern matching capabilities. Perl provides customary quote characters
+for these behaviors, but also provides a way for you to choose your
+quote character for any of them. In the following table, a C<{}> represents
+any pair of delimiters you choose.
+
+ Customary Generic Meaning Interpolates
+ '' q{} Literal no
+ "" qq{} Literal yes
+ `` qx{} Command yes*
+ qw{} Word list no
+ // m{} Pattern match yes*
+ qr{} Pattern yes*
+ s{}{} Substitution yes*
+ tr{}{} Transliteration no (but see below)
+ <<EOF here-doc yes*
+
+ * unless the delimiter is ''.
+
+Non-bracketing delimiters use the same character fore and aft, but the four
+sorts of brackets (round, angle, square, curly) will all nest, which means
+that
+
+ q{foo{bar}baz}
+
+is the same as
+
+ 'foo{bar}baz'
+
+Note, however, that this does not always work for quoting Perl code:
+
+ $s = q{ if($a eq "}") ... }; # WRONG
+
+is a syntax error. The C<Text::Balanced> module (from CPAN, and
+starting from Perl 5.8 part of the standard distribution) is able
+to do this properly.
+
+There can be whitespace between the operator and the quoting
+characters, except when C<#> is being used as the quoting character.
+C<q#foo#> is parsed as the string C<foo>, while C<q #foo#> is the
+operator C<q> followed by a comment. Its argument will be taken
+from the next line. This allows you to write:
+
+ s {foo} # Replace foo
+ {bar} # with bar.
+
+The following escape sequences are available in constructs that interpolate
+and in transliterations.
+X<\t> X<\n> X<\r> X<\f> X<\b> X<\a> X<\e> X<\x> X<\0> X<\c> X<\N>
+
+ \t tab (HT, TAB)
+ \n newline (NL)
+ \r return (CR)
+ \f form feed (FF)
+ \b backspace (BS)
+ \a alarm (bell) (BEL)
+ \e escape (ESC)
+ \033 octal char (example: ESC)
+ \x1b hex char (example: ESC)
+ \x{263a} wide hex char (example: SMILEY)
+ \c[ control char (example: ESC)
+ \N{name} named Unicode character
+ \N{U+263D} Unicode character (example: FIRST QUARTER MOON)
+
+The character following C<\c> is mapped to some other character by
+converting letters to upper case and then (on ASCII systems) by inverting
+the 7th bit (0x40). The most interesting range is from '@' to '_'
+(0x40 through 0x5F), resulting in a control character from 0x00
+through 0x1F. A '?' maps to the DEL character. On EBCDIC systems only
+'@', the letters, '[', '\', ']', '^', '_' and '?' will work, resulting
+in 0x00 through 0x1F and 0x7F.
+
+C<\N{U+I<wide hex char>}> means the Unicode character whose Unicode ordinal
+number is I<wide hex char>.
+For documentation of C<\N{name}>, see L<charnames>.
+
+B<NOTE>: Unlike C and other languages, Perl has no C<\v> escape sequence for
+the vertical tab (VT - ASCII 11), but you may use C<\ck> or C<\x0b>. (C<\v>
+does have meaning in regular expression patterns in Perl, see L<perlre>.)
+
+The following escape sequences are available in constructs that interpolate,
+but not in transliterations.
+X<\l> X<\u> X<\L> X<\U> X<\E> X<\Q>
+
+ \l lowercase next char
+ \u uppercase next char
+ \L lowercase till \E
+ \U uppercase till \E
+ \E end case modification
+ \Q quote non-word characters till \E
+
+If C<use locale> is in effect, the case map used by C<\l>, C<\L>,
+C<\u> and C<\U> is taken from the current locale. See L<perllocale>.
+If Unicode (for example, C<\N{}> or wide hex characters of 0x100 or
+beyond) is being used, the case map used by C<\l>, C<\L>, C<\u> and
+C<\U> is as defined by Unicode.
+
+All systems use the virtual C<"\n"> to represent a line terminator,
+called a "newline". There is no such thing as an unvarying, physical
+newline character. It is only an illusion that the operating system,
+device drivers, C libraries, and Perl all conspire to preserve. Not all
+systems read C<"\r"> as ASCII CR and C<"\n"> as ASCII LF. For example,
+on a Mac, these are reversed, and on systems without line terminator,
+printing C<"\n"> may emit no actual data. In general, use C<"\n"> when
+you mean a "newline" for your system, but use the literal ASCII when you
+need an exact character. For example, most networking protocols expect
+and prefer a CR+LF (C<"\015\012"> or C<"\cM\cJ">) for line terminators,
+and although they often accept just C<"\012">, they seldom tolerate just
+C<"\015">. If you get in the habit of using C<"\n"> for networking,
+you may be burned some day.
+X<newline> X<line terminator> X<eol> X<end of line>
+X<\n> X<\r> X<\r\n>
+
+For constructs that do interpolate, variables beginning with "C<$>"
+or "C<@>" are interpolated. Subscripted variables such as C<$a[3]> or
+C<< $href->{key}[0] >> are also interpolated, as are array and hash slices.
+But method calls such as C<< $obj->meth >> are not.
+
+Interpolating an array or slice interpolates the elements in order,
+separated by the value of C<$">, so is equivalent to interpolating
+C<join $", @array>. "Punctuation" arrays such as C<@*> are only
+interpolated if the name is enclosed in braces C<@{*}>, but special
+arrays C<@_>, C<@+>, and C<@-> are interpolated, even without braces.
+
+You cannot include a literal C<$> or C<@> within a C<\Q> sequence.
+An unescaped C<$> or C<@> interpolates the corresponding variable,
+while escaping will cause the literal string C<\$> to be inserted.
+You'll need to write something like C<m/\Quser\E\@\Qhost/>.
+
+Patterns are subject to an additional level of interpretation as a
+regular expression. This is done as a second pass, after variables are
+interpolated, so that regular expressions may be incorporated into the
+pattern from the variables. If this is not what you want, use C<\Q> to
+interpolate a variable literally.
+
+Apart from the behavior described above, Perl does not expand
+multiple levels of interpolation. In particular, contrary to the
+expectations of shell programmers, back-quotes do I<NOT> interpolate
+within double quotes, nor do single quotes impede evaluation of
+variables when used within double quotes.
+
+=head2 Regexp Quote-Like Operators
+X<operator, regexp>
+
+Here are the quote-like operators that apply to pattern
+matching and related activities.
+
+=over 8
+
+=item qr/STRING/msixpo
+X<qr> X</i> X</m> X</o> X</s> X</x> X</p>
+
+This operator quotes (and possibly compiles) its I<STRING> as a regular
+expression. I<STRING> is interpolated the same way as I<PATTERN>
+in C<m/PATTERN/>. If "'" is used as the delimiter, no interpolation
+is done. Returns a Perl value which may be used instead of the
+corresponding C</STRING/msixpo> expression. The returned value is a
+normalized version of the original pattern. It magically differs from
+a string containing the same characters: C<ref(qr/x/)> returns "Regexp",
+even though dereferencing the result returns undef.
+
+For example,
+
+ $rex = qr/my.STRING/is;
+ print $rex; # prints (?si-xm:my.STRING)
+ s/$rex/foo/;
+
+is equivalent to
+
+ s/my.STRING/foo/is;
+
+The result may be used as a subpattern in a match:
+
+ $re = qr/$pattern/;
+ $string =~ /foo${re}bar/; # can be interpolated in other patterns
+ $string =~ $re; # or used standalone
+ $string =~ /$re/; # or this way
+
+Since Perl may compile the pattern at the moment of execution of qr()
+operator, using qr() may have speed advantages in some situations,
+notably if the result of qr() is used standalone:
+
+ sub match {
+ my $patterns = shift;
+ my @compiled = map qr/$_/i, @$patterns;
+ grep {
+ my $success = 0;
+ foreach my $pat (@compiled) {
+ $success = 1, last if /$pat/;
+ }
+ $success;
+ } @_;
+ }
+
+Precompilation of the pattern into an internal representation at
+the moment of qr() avoids a need to recompile the pattern every
+time a match C</$pat/> is attempted. (Perl has many other internal
+optimizations, but none would be triggered in the above example if
+we did not use qr() operator.)
+
+Options are:
+
+ m Treat string as multiple lines.
+ s Treat string as single line. (Make . match a newline)
+ i Do case-insensitive pattern matching.
+ x Use extended regular expressions.
+ p When matching preserve a copy of the matched string so
+ that ${^PREMATCH}, ${^MATCH}, ${^POSTMATCH} will be defined.
+ o Compile pattern only once.
+
+If a precompiled pattern is embedded in a larger pattern then the effect
+of 'msixp' will be propagated appropriately. The effect of the 'o'
+modifier has is not propagated, being restricted to those patterns
+explicitly using it.
+
+See L<perlre> for additional information on valid syntax for STRING, and
+for a detailed look at the semantics of regular expressions.
+
+=item m/PATTERN/msixpogc
+X<m> X<operator, match>
+X<regexp, options> X<regexp> X<regex, options> X<regex>
+X</m> X</s> X</i> X</x> X</p> X</o> X</g> X</c>
+
+=item /PATTERN/msixpogc
+
+Searches a string for a pattern match, and in scalar context returns
+true if it succeeds, false if it fails. If no string is specified
+via the C<=~> or C<!~> operator, the $_ string is searched. (The
+string specified with C<=~> need not be an lvalue--it may be the
+result of an expression evaluation, but remember the C<=~> binds
+rather tightly.) See also L<perlre>. See L<perllocale> for
+discussion of additional considerations that apply when C<use locale>
+is in effect.
+
+Options are as described in C<qr//>; in addition, the following match
+process modifiers are available:
+
+ g Match globally, i.e., find all occurrences.
+ c Do not reset search position on a failed match when /g is in effect.
+
+If "/" is the delimiter then the initial C<m> is optional. With the C<m>
+you can use any pair of non-whitespace characters
+as delimiters. This is particularly useful for matching path names
+that contain "/", to avoid LTS (leaning toothpick syndrome). If "?" is
+the delimiter, then the match-only-once rule of C<?PATTERN?> applies.
+If "'" is the delimiter, no interpolation is performed on the PATTERN.
+When using a character valid in an identifier, whitespace is required
+after the C<m>.
+
+PATTERN may contain variables, which will be interpolated (and the
+pattern recompiled) every time the pattern search is evaluated, except
+for when the delimiter is a single quote. (Note that C<$(>, C<$)>, and
+C<$|> are not interpolated because they look like end-of-string tests.)
+If you want such a pattern to be compiled only once, add a C</o> after
+the trailing delimiter. This avoids expensive run-time recompilations,
+and is useful when the value you are interpolating won't change over
+the life of the script. However, mentioning C</o> constitutes a promise
+that you won't change the variables in the pattern. If you change them,
+Perl won't even notice. See also L<"qr/STRING/msixpo">.
+
+=item The empty pattern //
+
+If the PATTERN evaluates to the empty string, the last
+I<successfully> matched regular expression is used instead. In this
+case, only the C<g> and C<c> flags on the empty pattern is honoured -
+the other flags are taken from the original pattern. If no match has
+previously succeeded, this will (silently) act instead as a genuine
+empty pattern (which will always match).
+
+Note that it's possible to confuse Perl into thinking C<//> (the empty
+regex) is really C<//> (the defined-or operator). Perl is usually pretty
+good about this, but some pathological cases might trigger this, such as
+C<$a///> (is that C<($a) / (//)> or C<$a // />?) and C<print $fh //>
+(C<print $fh(//> or C<print($fh //>?). In all of these examples, Perl
+will assume you meant defined-or. If you meant the empty regex, just
+use parentheses or spaces to disambiguate, or even prefix the empty
+regex with an C<m> (so C<//> becomes C<m//>).
+
+=item Matching in list context
+
+If the C</g> option is not used, C<m//> in list context returns a
+list consisting of the subexpressions matched by the parentheses in the
+pattern, i.e., (C<$1>, C<$2>, C<$3>...). (Note that here C<$1> etc. are
+also set, and that this differs from Perl 4's behavior.) When there are
+no parentheses in the pattern, the return value is the list C<(1)> for
+success. With or without parentheses, an empty list is returned upon
+failure.
+
+Examples:
+
+ open(TTY, '/dev/tty');
+ <TTY> =~ /^y/i && foo(); # do foo if desired
+
+ if (/Version: *([0-9.]*)/) { $version = $1; }
+
+ next if m#^/usr/spool/uucp#;
+
+ # poor man's grep
+ $arg = shift;
+ while (<>) {
+ print if /$arg/o; # compile only once
+ }
+
+ if (($F1, $F2, $Etc) = ($foo =~ /^(\S+)\s+(\S+)\s*(.*)/))
+
+This last example splits $foo into the first two words and the
+remainder of the line, and assigns those three fields to $F1, $F2, and
+$Etc. The conditional is true if any variables were assigned, i.e., if
+the pattern matched.
+
+The C</g> modifier specifies global pattern matching--that is,
+matching as many times as possible within the string. How it behaves
+depends on the context. In list context, it returns a list of the
+substrings matched by any capturing parentheses in the regular
+expression. If there are no parentheses, it returns a list of all
+the matched strings, as if there were parentheses around the whole
+pattern.
+
+In scalar context, each execution of C<m//g> finds the next match,
+returning true if it matches, and false if there is no further match.
+The position after the last match can be read or set using the pos()
+function; see L<perlfunc/pos>. A failed match normally resets the
+search position to the beginning of the string, but you can avoid that
+by adding the C</c> modifier (e.g. C<m//gc>). Modifying the target
+string also resets the search position.
+
+=item \G assertion
+
+You can intermix C<m//g> matches with C<m/\G.../g>, where C<\G> is a
+zero-width assertion that matches the exact position where the previous
+C<m//g>, if any, left off. Without the C</g> modifier, the C<\G> assertion
+still anchors at pos(), but the match is of course only attempted once.
+Using C<\G> without C</g> on a target string that has not previously had a
+C</g> match applied to it is the same as using the C<\A> assertion to match
+the beginning of the string. Note also that, currently, C<\G> is only
+properly supported when anchored at the very beginning of the pattern.
+
+Examples:
+
+ # list context
+ ($one,$five,$fifteen) = (`uptime` =~ /(\d+\.\d+)/g);
+
+ # scalar context
+ $/ = "";
+ while (defined($paragraph = <>)) {
+ while ($paragraph =~ /[a-z]['")]*[.!?]+['")]*\s/g) {
+ $sentences++;
+ }
+ }
+ print "$sentences\n";
+
+ # using m//gc with \G
+ $_ = "ppooqppqq";
+ while ($i++ < 2) {
+ print "1: '";
+ print $1 while /(o)/gc; print "', pos=", pos, "\n";
+ print "2: '";
+ print $1 if /\G(q)/gc; print "', pos=", pos, "\n";
+ print "3: '";
+ print $1 while /(p)/gc; print "', pos=", pos, "\n";
+ }
+ print "Final: '$1', pos=",pos,"\n" if /\G(.)/;
+
+The last example should print:
+
+ 1: 'oo', pos=4
+ 2: 'q', pos=5
+ 3: 'pp', pos=7
+ 1: '', pos=7
+ 2: 'q', pos=8
+ 3: '', pos=8
+ Final: 'q', pos=8
+
+Notice that the final match matched C<q> instead of C<p>, which a match
+without the C<\G> anchor would have done. Also note that the final match
+did not update C<pos>. C<pos> is only updated on a C</g> match. If the
+final match did indeed match C<p>, it's a good bet that you're running an
+older (pre-5.6.0) Perl.
+
+A useful idiom for C<lex>-like scanners is C</\G.../gc>. You can
+combine several regexps like this to process a string part-by-part,
+doing different actions depending on which regexp matched. Each
+regexp tries to match where the previous one leaves off.
+
+ $_ = <<'EOL';
+ $url = URI::URL->new( "http://example.com/" ); die if $url eq "xXx";
+ EOL
+ LOOP:
+ {
+ print(" digits"), redo LOOP if /\G\d+\b[,.;]?\s*/gc;
+ print(" lowercase"), redo LOOP if /\G[a-z]+\b[,.;]?\s*/gc;
+ print(" UPPERCASE"), redo LOOP if /\G[A-Z]+\b[,.;]?\s*/gc;
+ print(" Capitalized"), redo LOOP if /\G[A-Z][a-z]+\b[,.;]?\s*/gc;
+ print(" MiXeD"), redo LOOP if /\G[A-Za-z]+\b[,.;]?\s*/gc;
+ print(" alphanumeric"), redo LOOP if /\G[A-Za-z0-9]+\b[,.;]?\s*/gc;
+ print(" line-noise"), redo LOOP if /\G[^A-Za-z0-9]+/gc;
+ print ". That's all!\n";
+ }
+
+Here is the output (split into several lines):
+
+ line-noise lowercase line-noise lowercase UPPERCASE line-noise
+ UPPERCASE line-noise lowercase line-noise lowercase line-noise
+ lowercase lowercase line-noise lowercase lowercase line-noise
+ MiXeD line-noise. That's all!
+
+=item ?PATTERN?
+X<?>
+
+This is just like the C</pattern/> search, except that it matches only
+once between calls to the reset() operator. This is a useful
+optimization when you want to see only the first occurrence of
+something in each file of a set of files, for instance. Only C<??>
+patterns local to the current package are reset.
+
+ while (<>) {
+ if (?^$?) {
+ # blank line between header and body
+ }
+ } continue {
+ reset if eof; # clear ?? status for next file
+ }
+
+This usage is vaguely deprecated, which means it just might possibly
+be removed in some distant future version of Perl, perhaps somewhere
+around the year 2168.
+
+=item s/PATTERN/REPLACEMENT/msixpogce
+X<substitute> X<substitution> X<replace> X<regexp, replace>
+X<regexp, substitute> X</m> X</s> X</i> X</x> X</p> X</o> X</g> X</c> X</e>
+
+Searches a string for a pattern, and if found, replaces that pattern
+with the replacement text and returns the number of substitutions
+made. Otherwise it returns false (specifically, the empty string).
+
+If no string is specified via the C<=~> or C<!~> operator, the C<$_>
+variable is searched and modified. (The string specified with C<=~> must
+be scalar variable, an array element, a hash element, or an assignment
+to one of those, i.e., an lvalue.)
+
+If the delimiter chosen is a single quote, no interpolation is
+done on either the PATTERN or the REPLACEMENT. Otherwise, if the
+PATTERN contains a $ that looks like a variable rather than an
+end-of-string test, the variable will be interpolated into the pattern
+at run-time. If you want the pattern compiled only once the first time
+the variable is interpolated, use the C</o> option. If the pattern
+evaluates to the empty string, the last successfully executed regular
+expression is used instead. See L<perlre> for further explanation on these.
+See L<perllocale> for discussion of additional considerations that apply
+when C<use locale> is in effect.
+
+Options are as with m// with the addition of the following replacement
+specific options:
+
+ e Evaluate the right side as an expression.
+ ee Evaluate the right side as a string then eval the result
+
+Any non-whitespace delimiter may replace the slashes. Add space after
+the C<s> when using a character allowed in identifiers. If single quotes
+are used, no interpretation is done on the replacement string (the C</e>
+modifier overrides this, however). Unlike Perl 4, Perl 5 treats backticks
+as normal delimiters; the replacement text is not evaluated as a command.
+If the PATTERN is delimited by bracketing quotes, the REPLACEMENT has
+its own pair of quotes, which may or may not be bracketing quotes, e.g.,
+C<s(foo)(bar)> or C<< s<foo>/bar/ >>. A C</e> will cause the
+replacement portion to be treated as a full-fledged Perl expression
+and evaluated right then and there. It is, however, syntax checked at
+compile-time. A second C<e> modifier will cause the replacement portion
+to be C<eval>ed before being run as a Perl expression.
+
+Examples:
+
+ s/\bgreen\b/mauve/g; # don't change wintergreen
+
+ $path =~ s|/usr/bin|/usr/local/bin|;
+
+ s/Login: $foo/Login: $bar/; # run-time pattern
+
+ ($foo = $bar) =~ s/this/that/; # copy first, then change
+
+ $count = ($paragraph =~ s/Mister\b/Mr./g); # get change-count
+
+ $_ = 'abc123xyz';
+ s/\d+/$&*2/e; # yields 'abc246xyz'
+ s/\d+/sprintf("%5d",$&)/e; # yields 'abc 246xyz'
+ s/\w/$& x 2/eg; # yields 'aabbcc 224466xxyyzz'
+
+ s/%(.)/$percent{$1}/g; # change percent escapes; no /e
+ s/%(.)/$percent{$1} || $&/ge; # expr now, so /e
+ s/^=(\w+)/pod($1)/ge; # use function call
+
+ # expand variables in $_, but dynamics only, using
+ # symbolic dereferencing
+ s/\$(\w+)/${$1}/g;
+
+ # Add one to the value of any numbers in the string
+ s/(\d+)/1 + $1/eg;
+
+ # This will expand any embedded scalar variable
+ # (including lexicals) in $_ : First $1 is interpolated
+ # to the variable name, and then evaluated
+ s/(\$\w+)/$1/eeg;
+
+ # Delete (most) C comments.
+ $program =~ s {
+ /\* # Match the opening delimiter.
+ .*? # Match a minimal number of characters.
+ \*/ # Match the closing delimiter.
+ } []gsx;
+
+ s/^\s*(.*?)\s*$/$1/; # trim whitespace in $_, expensively
+
+ for ($variable) { # trim whitespace in $variable, cheap
+ s/^\s+//;
+ s/\s+$//;
+ }
+
+ s/([^ ]*) *([^ ]*)/$2 $1/; # reverse 1st two fields
+
+Note the use of $ instead of \ in the last example. Unlike
+B<sed>, we use the \<I<digit>> form in only the left hand side.
+Anywhere else it's $<I<digit>>.
+
+Occasionally, you can't use just a C</g> to get all the changes
+to occur that you might want. Here are two common cases:
+
+ # put commas in the right places in an integer
+ 1 while s/(\d)(\d\d\d)(?!\d)/$1,$2/g;
+
+ # expand tabs to 8-column spacing
+ 1 while s/\t+/' ' x (length($&)*8 - length($`)%8)/e;
+
+=back
+
+=head2 Quote-Like Operators
+X<operator, quote-like>
+
+=over 4
+
+=item q/STRING/
+X<q> X<quote, single> X<'> X<''>
+
+=item 'STRING'
+
+A single-quoted, literal string. A backslash represents a backslash
+unless followed by the delimiter or another backslash, in which case
+the delimiter or backslash is interpolated.
+
+ $foo = q!I said, "You said, 'She said it.'"!;
+ $bar = q('This is it.');
+ $baz = '\n'; # a two-character string
+
+=item qq/STRING/
+X<qq> X<quote, double> X<"> X<"">
+
+=item "STRING"
+
+A double-quoted, interpolated string.
+
+ $_ .= qq
+ (*** The previous line contains the naughty word "$1".\n)
+ if /\b(tcl|java|python)\b/i; # :-)
+ $baz = "\n"; # a one-character string
+
+=item qx/STRING/
+X<qx> X<`> X<``> X<backtick>
+
+=item `STRING`
+
+A string which is (possibly) interpolated and then executed as a
+system command with C</bin/sh> or its equivalent. Shell wildcards,
+pipes, and redirections will be honored. The collected standard
+output of the command is returned; standard error is unaffected. In
+scalar context, it comes back as a single (potentially multi-line)
+string, or undef if the command failed. In list context, returns a
+list of lines (however you've defined lines with $/ or
+$INPUT_RECORD_SEPARATOR), or an empty list if the command failed.
+
+Because backticks do not affect standard error, use shell file descriptor
+syntax (assuming the shell supports this) if you care to address this.
+To capture a command's STDERR and STDOUT together:
+
+ $output = `cmd 2>&1`;
+
+To capture a command's STDOUT but discard its STDERR:
+
+ $output = `cmd 2>/dev/null`;
+
+To capture a command's STDERR but discard its STDOUT (ordering is
+important here):
+
+ $output = `cmd 2>&1 1>/dev/null`;
+
+To exchange a command's STDOUT and STDERR in order to capture the STDERR
+but leave its STDOUT to come out the old STDERR:
+
+ $output = `cmd 3>&1 1>&2 2>&3 3>&-`;
+
+To read both a command's STDOUT and its STDERR separately, it's easiest
+to redirect them separately to files, and then read from those files
+when the program is done:
+
+ system("program args 1>program.stdout 2>program.stderr");
+
+The STDIN filehandle used by the command is inherited from Perl's STDIN.
+For example:
+
+ open BLAM, "blam" || die "Can't open: $!";
+ open STDIN, "<&BLAM";
+ print `sort`;
+
+will print the sorted contents of the file "blam".
+
+Using single-quote as a delimiter protects the command from Perl's
+double-quote interpolation, passing it on to the shell instead:
+
+ $perl_info = qx(ps $$); # that's Perl's $$
+ $shell_info = qx'ps $$'; # that's the new shell's $$
+
+How that string gets evaluated is entirely subject to the command
+interpreter on your system. On most platforms, you will have to protect
+shell metacharacters if you want them treated literally. This is in
+practice difficult to do, as it's unclear how to escape which characters.
+See L<perlsec> for a clean and safe example of a manual fork() and exec()
+to emulate backticks safely.
+
+On some platforms (notably DOS-like ones), the shell may not be
+capable of dealing with multiline commands, so putting newlines in
+the string may not get you what you want. You may be able to evaluate
+multiple commands in a single line by separating them with the command
+separator character, if your shell supports that (e.g. C<;> on many Unix
+shells; C<&> on the Windows NT C<cmd> shell).
+
+Beginning with v5.6.0, Perl will attempt to flush all files opened for
+output before starting the child process, but this may not be supported
+on some platforms (see L<perlport>). To be safe, you may need to set
+C<$|> ($AUTOFLUSH in English) or call the C<autoflush()> method of
+C<IO::Handle> on any open handles.
+
+Beware that some command shells may place restrictions on the length
+of the command line. You must ensure your strings don't exceed this
+limit after any necessary interpolations. See the platform-specific
+release notes for more details about your particular environment.
+
+Using this operator can lead to programs that are difficult to port,
+because the shell commands called vary between systems, and may in
+fact not be present at all. As one example, the C<type> command under
+the POSIX shell is very different from the C<type> command under DOS.
+That doesn't mean you should go out of your way to avoid backticks
+when they're the right way to get something done. Perl was made to be
+a glue language, and one of the things it glues together is commands.
+Just understand what you're getting yourself into.
+
+See L</"I/O Operators"> for more discussion.
+
+=item qw/STRING/
+X<qw> X<quote, list> X<quote, words>
+
+Evaluates to a list of the words extracted out of STRING, using embedded
+whitespace as the word delimiters. It can be understood as being roughly
+equivalent to:
+
+ split(' ', q/STRING/);
+
+the differences being that it generates a real list at compile time, and
+in scalar context it returns the last element in the list. So
+this expression:
+
+ qw(foo bar baz)
+
+is semantically equivalent to the list:
+
+ 'foo', 'bar', 'baz'
+
+Some frequently seen examples:
+
+ use POSIX qw( setlocale localeconv )
+ @EXPORT = qw( foo bar baz );
+
+A common mistake is to try to separate the words with comma or to
+put comments into a multi-line C<qw>-string. For this reason, the
+C<use warnings> pragma and the B<-w> switch (that is, the C<$^W> variable)
+produces warnings if the STRING contains the "," or the "#" character.
+
+
+=item tr/SEARCHLIST/REPLACEMENTLIST/cds
+X<tr> X<y> X<transliterate> X</c> X</d> X</s>
+
+=item y/SEARCHLIST/REPLACEMENTLIST/cds
+
+Transliterates all occurrences of the characters found in the search list
+with the corresponding character in the replacement list. It returns
+the number of characters replaced or deleted. If no string is
+specified via the =~ or !~ operator, the $_ string is transliterated. (The
+string specified with =~ must be a scalar variable, an array element, a
+hash element, or an assignment to one of those, i.e., an lvalue.)
+
+A character range may be specified with a hyphen, so C<tr/A-J/0-9/>
+does the same replacement as C<tr/ACEGIBDFHJ/0246813579/>.
+For B<sed> devotees, C<y> is provided as a synonym for C<tr>. If the
+SEARCHLIST is delimited by bracketing quotes, the REPLACEMENTLIST has
+its own pair of quotes, which may or may not be bracketing quotes,
+e.g., C<tr[A-Z][a-z]> or C<tr(+\-*/)/ABCD/>.
+
+Note that C<tr> does B<not> do regular expression character classes
+such as C<\d> or C<[:lower:]>. The C<tr> operator is not equivalent to
+the tr(1) utility. If you want to map strings between lower/upper
+cases, see L<perlfunc/lc> and L<perlfunc/uc>, and in general consider
+using the C<s> operator if you need regular expressions.
+
+Note also that the whole range idea is rather unportable between
+character sets--and even within character sets they may cause results
+you probably didn't expect. A sound principle is to use only ranges
+that begin from and end at either alphabets of equal case (a-e, A-E),
+or digits (0-4). Anything else is unsafe. If in doubt, spell out the
+character sets in full.
+
+Options:
+
+ c Complement the SEARCHLIST.
+ d Delete found but unreplaced characters.
+ s Squash duplicate replaced characters.
+
+If the C</c> modifier is specified, the SEARCHLIST character set
+is complemented. If the C</d> modifier is specified, any characters
+specified by SEARCHLIST not found in REPLACEMENTLIST are deleted.
+(Note that this is slightly more flexible than the behavior of some
+B<tr> programs, which delete anything they find in the SEARCHLIST,
+period.) If the C</s> modifier is specified, sequences of characters
+that were transliterated to the same character are squashed down
+to a single instance of the character.
+
+If the C</d> modifier is used, the REPLACEMENTLIST is always interpreted
+exactly as specified. Otherwise, if the REPLACEMENTLIST is shorter
+than the SEARCHLIST, the final character is replicated till it is long
+enough. If the REPLACEMENTLIST is empty, the SEARCHLIST is replicated.
+This latter is useful for counting characters in a class or for
+squashing character sequences in a class.
+
+Examples:
+
+ $ARGV[1] =~ tr/A-Z/a-z/; # canonicalize to lower case
+
+ $cnt = tr/*/*/; # count the stars in $_
+
+ $cnt = $sky =~ tr/*/*/; # count the stars in $sky
+
+ $cnt = tr/0-9//; # count the digits in $_
+
+ tr/a-zA-Z//s; # bookkeeper -> bokeper
+
+ ($HOST = $host) =~ tr/a-z/A-Z/;
+
+ tr/a-zA-Z/ /cs; # change non-alphas to single space
+
+ tr [\200-\377]
+ [\000-\177]; # delete 8th bit
+
+If multiple transliterations are given for a character, only the
+first one is used:
+
+ tr/AAA/XYZ/
+
+will transliterate any A to X.
+
+Because the transliteration table is built at compile time, neither
+the SEARCHLIST nor the REPLACEMENTLIST are subjected to double quote
+interpolation. That means that if you want to use variables, you
+must use an eval():
+
+ eval "tr/$oldlist/$newlist/";
+ die $@ if $@;
+
+ eval "tr/$oldlist/$newlist/, 1" or die $@;
+
+=item <<EOF
+X<here-doc> X<heredoc> X<here-document> X<<< << >>>
+
+A line-oriented form of quoting is based on the shell "here-document"
+syntax. Following a C<< << >> you specify a string to terminate
+the quoted material, and all lines following the current line down to
+the terminating string are the value of the item.
+
+The terminating string may be either an identifier (a word), or some
+quoted text. An unquoted identifier works like double quotes.
+There may not be a space between the C<< << >> and the identifier,
+unless the identifier is explicitly quoted. (If you put a space it
+will be treated as a null identifier, which is valid, and matches the
+first empty line.) The terminating string must appear by itself
+(unquoted and with no surrounding whitespace) on the terminating line.
+
+If the terminating string is quoted, the type of quotes used determine
+the treatment of the text.
+
+=over 4
+
+=item Double Quotes
+
+Double quotes indicate that the text will be interpolated using exactly
+the same rules as normal double quoted strings.
+
+ print <<EOF;
+ The price is $Price.
+ EOF
+
+ print << "EOF"; # same as above
+ The price is $Price.
+ EOF
+
+
+=item Single Quotes
+
+Single quotes indicate the text is to be treated literally with no
+interpolation of its content. This is similar to single quoted
+strings except that backslashes have no special meaning, with C<\\>
+being treated as two backslashes and not one as they would in every
+other quoting construct.
+
+This is the only form of quoting in perl where there is no need
+to worry about escaping content, something that code generators
+can and do make good use of.
+
+=item Backticks
+
+The content of the here doc is treated just as it would be if the
+string were embedded in backticks. Thus the content is interpolated
+as though it were double quoted and then executed via the shell, with
+the results of the execution returned.
+
+ print << `EOC`; # execute command and get results
+ echo hi there
+ EOC
+
+=back
+
+It is possible to stack multiple here-docs in a row:
+
+ print <<"foo", <<"bar"; # you can stack them
+ I said foo.
+ foo
+ I said bar.
+ bar
+
+ myfunc(<< "THIS", 23, <<'THAT');
+ Here's a line
+ or two.
+ THIS
+ and here's another.
+ THAT
+
+Just don't forget that you have to put a semicolon on the end
+to finish the statement, as Perl doesn't know you're not going to
+try to do this:
+
+ print <<ABC
+ 179231
+ ABC
+ + 20;
+
+If you want to remove the line terminator from your here-docs,
+use C<chomp()>.
+
+ chomp($string = <<'END');
+ This is a string.
+ END
+
+If you want your here-docs to be indented with the rest of the code,
+you'll need to remove leading whitespace from each line manually:
+
+ ($quote = <<'FINIS') =~ s/^\s+//gm;
+ The Road goes ever on and on,
+ down from the door where it began.
+ FINIS
+
+If you use a here-doc within a delimited construct, such as in C<s///eg>,
+the quoted material must come on the lines following the final delimiter.
+So instead of
+
+ s/this/<<E . 'that'
+ the other
+ E
+ . 'more '/eg;
+
+you have to write
+
+ s/this/<<E . 'that'
+ . 'more '/eg;
+ the other
+ E
+
+If the terminating identifier is on the last line of the program, you
+must be sure there is a newline after it; otherwise, Perl will give the
+warning B<Can't find string terminator "END" anywhere before EOF...>.
+
+Additionally, the quoting rules for the end of string identifier are not
+related to Perl's quoting rules. C<q()>, C<qq()>, and the like are not
+supported in place of C<''> and C<"">, and the only interpolation is for
+backslashing the quoting character:
+
+ print << "abc\"def";
+ testing...
+ abc"def
+
+Finally, quoted strings cannot span multiple lines. The general rule is
+that the identifier must be a string literal. Stick with that, and you
+should be safe.
+
+=back
+
+=head2 Gory details of parsing quoted constructs
+X<quote, gory details>
+
+When presented with something that might have several different
+interpretations, Perl uses the B<DWIM> (that's "Do What I Mean")
+principle to pick the most probable interpretation. This strategy
+is so successful that Perl programmers often do not suspect the
+ambivalence of what they write. But from time to time, Perl's
+notions differ substantially from what the author honestly meant.
+
+This section hopes to clarify how Perl handles quoted constructs.
+Although the most common reason to learn this is to unravel labyrinthine
+regular expressions, because the initial steps of parsing are the
+same for all quoting operators, they are all discussed together.
+
+The most important Perl parsing rule is the first one discussed
+below: when processing a quoted construct, Perl first finds the end
+of that construct, then interprets its contents. If you understand
+this rule, you may skip the rest of this section on the first
+reading. The other rules are likely to contradict the user's
+expectations much less frequently than this first one.
+
+Some passes discussed below are performed concurrently, but because
+their results are the same, we consider them individually. For different
+quoting constructs, Perl performs different numbers of passes, from
+one to four, but these passes are always performed in the same order.
+
+=over 4
+
+=item Finding the end
+
+The first pass is finding the end of the quoted construct, where
+the information about the delimiters is used in parsing.
+During this search, text between the starting and ending delimiters
+is copied to a safe location. The text copied gets delimiter-independent.
+
+If the construct is a here-doc, the ending delimiter is a line
+that has a terminating string as the content. Therefore C<<<EOF> is
+terminated by C<EOF> immediately followed by C<"\n"> and starting
+from the first column of the terminating line.
+When searching for the terminating line of a here-doc, nothing
+is skipped. In other words, lines after the here-doc syntax
+are compared with the terminating string line by line.
+
+For the constructs except here-docs, single characters are used as starting
+and ending delimiters. If the starting delimiter is an opening punctuation
+(that is C<(>, C<[>, C<{>, or C<< < >>), the ending delimiter is the
+corresponding closing punctuation (that is C<)>, C<]>, C<}>, or C<< > >>).
+If the starting delimiter is an unpaired character like C</> or a closing
+punctuation, the ending delimiter is same as the starting delimiter.
+Therefore a C</> terminates a C<qq//> construct, while a C<]> terminates
+C<qq[]> and C<qq]]> constructs.
+
+When searching for single-character delimiters, escaped delimiters
+and C<\\> are skipped. For example, while searching for terminating C</>,
+combinations of C<\\> and C<\/> are skipped. If the delimiters are
+bracketing, nested pairs are also skipped. For example, while searching
+for closing C<]> paired with the opening C<[>, combinations of C<\\>, C<\]>,
+and C<\[> are all skipped, and nested C<[> and C<]> are skipped as well.
+However, when backslashes are used as the delimiters (like C<qq\\> and
+C<tr\\\>), nothing is skipped.
+During the search for the end, backslashes that escape delimiters
+are removed (exactly speaking, they are not copied to the safe location).
+
+For constructs with three-part delimiters (C<s///>, C<y///>, and
+C<tr///>), the search is repeated once more.
+If the first delimiter is not an opening punctuation, three delimiters must
+be same such as C<s!!!> and C<tr)))>, in which case the second delimiter
+terminates the left part and starts the right part at once.
+If the left part is delimited by bracketing punctuations (that is C<()>,
+C<[]>, C<{}>, or C<< <> >>), the right part needs another pair of
+delimiters such as C<s(){}> and C<tr[]//>. In these cases, whitespaces
+and comments are allowed between both parts, though the comment must follow
+at least one whitespace; otherwise a character expected as the start of
+the comment may be regarded as the starting delimiter of the right part.
+
+During this search no attention is paid to the semantics of the construct.
+Thus:
+
+ "$hash{"$foo/$bar"}"
+
+or:
+
+ m/
+ bar # NOT a comment, this slash / terminated m//!
+ /x
+
+do not form legal quoted expressions. The quoted part ends on the
+first C<"> and C</>, and the rest happens to be a syntax error.
+Because the slash that terminated C<m//> was followed by a C<SPACE>,
+the example above is not C<m//x>, but rather C<m//> with no C</x>
+modifier. So the embedded C<#> is interpreted as a literal C<#>.
+
+Also no attention is paid to C<\c\> (multichar control char syntax) during
+this search. Thus the second C<\> in C<qq/\c\/> is interpreted as a part
+of C<\/>, and the following C</> is not recognized as a delimiter.
+Instead, use C<\034> or C<\x1c> at the end of quoted constructs.
+
+=item Interpolation
+X<interpolation>
+
+The next step is interpolation in the text obtained, which is now
+delimiter-independent. There are multiple cases.
+
+=over 4
+
+=item C<<<'EOF'>
+
+No interpolation is performed.
+Note that the combination C<\\> is left intact, since escaped delimiters
+are not available for here-docs.
+
+=item C<m''>, the pattern of C<s'''>
+
+No interpolation is performed at this stage.
+Any backslashed sequences including C<\\> are treated at the stage
+to L</"parsing regular expressions">.
+
+=item C<''>, C<q//>, C<tr'''>, C<y'''>, the replacement of C<s'''>
+
+The only interpolation is removal of C<\> from pairs of C<\\>.
+Therefore C<-> in C<tr'''> and C<y'''> is treated literally
+as a hyphen and no character range is available.
+C<\1> in the replacement of C<s'''> does not work as C<$1>.
+
+=item C<tr///>, C<y///>
+
+No variable interpolation occurs. String modifying combinations for
+case and quoting such as C<\Q>, C<\U>, and C<\E> are not recognized.
+The other escape sequences such as C<\200> and C<\t> and backslashed
+characters such as C<\\> and C<\-> are converted to appropriate literals.
+The character C<-> is treated specially and therefore C<\-> is treated
+as a literal C<->.
+
+=item C<"">, C<``>, C<qq//>, C<qx//>, C<< <file*glob> >>, C<<<"EOF">
+
+C<\Q>, C<\U>, C<\u>, C<\L>, C<\l> (possibly paired with C<\E>) are
+converted to corresponding Perl constructs. Thus, C<"$foo\Qbaz$bar">
+is converted to C<$foo . (quotemeta("baz" . $bar))> internally.
+The other escape sequences such as C<\200> and C<\t> and backslashed
+characters such as C<\\> and C<\-> are replaced with appropriate
+expansions.
+
+Let it be stressed that I<whatever falls between C<\Q> and C<\E>>
+is interpolated in the usual way. Something like C<"\Q\\E"> has
+no C<\E> inside. instead, it has C<\Q>, C<\\>, and C<E>, so the
+result is the same as for C<"\\\\E">. As a general rule, backslashes
+between C<\Q> and C<\E> may lead to counterintuitive results. So,
+C<"\Q\t\E"> is converted to C<quotemeta("\t")>, which is the same
+as C<"\\\t"> (since TAB is not alphanumeric). Note also that:
+
+ $str = '\t';
+ return "\Q$str";
+
+may be closer to the conjectural I<intention> of the writer of C<"\Q\t\E">.
+
+Interpolated scalars and arrays are converted internally to the C<join> and
+C<.> catenation operations. Thus, C<"$foo XXX '@arr'"> becomes:
+
+ $foo . " XXX '" . (join $", @arr) . "'";
+
+All operations above are performed simultaneously, left to right.
+
+Because the result of C<"\Q STRING \E"> has all metacharacters
+quoted, there is no way to insert a literal C<$> or C<@> inside a
+C<\Q\E> pair. If protected by C<\>, C<$> will be quoted to became
+C<"\\\$">; if not, it is interpreted as the start of an interpolated
+scalar.
+
+Note also that the interpolation code needs to make a decision on
+where the interpolated scalar ends. For instance, whether
+C<< "a $b -> {c}" >> really means:
+
+ "a " . $b . " -> {c}";
+
+or:
+
+ "a " . $b -> {c};
+
+Most of the time, the longest possible text that does not include
+spaces between components and which contains matching braces or
+brackets. because the outcome may be determined by voting based
+on heuristic estimators, the result is not strictly predictable.
+Fortunately, it's usually correct for ambiguous cases.
+
+=item the replacement of C<s///>
+
+Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, and interpolation
+happens as with C<qq//> constructs.
+
+It is at this step that C<\1> is begrudgingly converted to C<$1> in
+the replacement text of C<s///>, in order to correct the incorrigible
+I<sed> hackers who haven't picked up the saner idiom yet. A warning
+is emitted if the C<use warnings> pragma or the B<-w> command-line flag
+(that is, the C<$^W> variable) was set.
+
+=item C<RE> in C<?RE?>, C</RE/>, C<m/RE/>, C<s/RE/foo/>,
+
+Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, C<\E>,
+and interpolation happens (almost) as with C<qq//> constructs.
+
+Processing of C<\N{...}> is also done here, and compiled into an intermediate
+form for the regex compiler. (This is because, as mentioned below, the regex
+compilation may be done at execution time, and C<\N{...}> is a compile-time
+construct.)
+
+However any other combinations of C<\> followed by a character
+are not substituted but only skipped, in order to parse them
+as regular expressions at the following step.
+As C<\c> is skipped at this step, C<@> of C<\c@> in RE is possibly
+treated as an array symbol (for example C<@foo>),
+even though the same text in C<qq//> gives interpolation of C<\c@>.
+
+Moreover, inside C<(?{BLOCK})>, C<(?# comment )>, and
+a C<#>-comment in a C<//x>-regular expression, no processing is
+performed whatsoever. This is the first step at which the presence
+of the C<//x> modifier is relevant.
+
+Interpolation in patterns has several quirks: C<$|>, C<$(>, C<$)>, C<@+>
+and C<@-> are not interpolated, and constructs C<$var[SOMETHING]> are
+voted (by several different estimators) to be either an array element
+or C<$var> followed by an RE alternative. This is where the notation
+C<${arr[$bar]}> comes handy: C</${arr[0-9]}/> is interpreted as
+array element C<-9>, not as a regular expression from the variable
+C<$arr> followed by a digit, which would be the interpretation of
+C</$arr[0-9]/>. Since voting among different estimators may occur,
+the result is not predictable.
+
+The lack of processing of C<\\> creates specific restrictions on
+the post-processed text. If the delimiter is C</>, one cannot get
+the combination C<\/> into the result of this step. C</> will
+finish the regular expression, C<\/> will be stripped to C</> on
+the previous step, and C<\\/> will be left as is. Because C</> is
+equivalent to C<\/> inside a regular expression, this does not
+matter unless the delimiter happens to be character special to the
+RE engine, such as in C<s*foo*bar*>, C<m[foo]>, or C<?foo?>; or an
+alphanumeric char, as in:
+
+ m m ^ a \s* b mmx;
+
+In the RE above, which is intentionally obfuscated for illustration, the
+delimiter is C<m>, the modifier is C<mx>, and after delimiter-removal the
+RE is the same as for C<m/ ^ a \s* b /mx>. There's more than one
+reason you're encouraged to restrict your delimiters to non-alphanumeric,
+non-whitespace choices.
+
+=back
+
+This step is the last one for all constructs except regular expressions,
+which are processed further.
+
+=item parsing regular expressions
+X<regexp, parse>
+
+Previous steps were performed during the compilation of Perl code,
+but this one happens at run time, although it may be optimized to
+be calculated at compile time if appropriate. After preprocessing
+described above, and possibly after evaluation if concatenation,
+joining, casing translation, or metaquoting are involved, the
+resulting I<string> is passed to the RE engine for compilation.
+
+Whatever happens in the RE engine might be better discussed in L<perlre>,
+but for the sake of continuity, we shall do so here.
+
+This is another step where the presence of the C<//x> modifier is
+relevant. The RE engine scans the string from left to right and
+converts it to a finite automaton.
+
+Backslashed characters are either replaced with corresponding
+literal strings (as with C<\{>), or else they generate special nodes
+in the finite automaton (as with C<\b>). Characters special to the
+RE engine (such as C<|>) generate corresponding nodes or groups of
+nodes. C<(?#...)> comments are ignored. All the rest is either
+converted to literal strings to match, or else is ignored (as is
+whitespace and C<#>-style comments if C<//x> is present).
+
+Parsing of the bracketed character class construct, C<[...]>, is
+rather different than the rule used for the rest of the pattern.
+The terminator of this construct is found using the same rules as
+for finding the terminator of a C<{}>-delimited construct, the only
+exception being that C<]> immediately following C<[> is treated as
+though preceded by a backslash. Similarly, the terminator of
+C<(?{...})> is found using the same rules as for finding the
+terminator of a C<{}>-delimited construct.
+
+It is possible to inspect both the string given to RE engine and the
+resulting finite automaton. See the arguments C<debug>/C<debugcolor>
+in the C<use L<re>> pragma, as well as Perl's B<-Dr> command-line
+switch documented in L<perlrun/"Command Switches">.
+
+=item Optimization of regular expressions
+X<regexp, optimization>
+
+This step is listed for completeness only. Since it does not change
+semantics, details of this step are not documented and are subject
+to change without notice. This step is performed over the finite
+automaton that was generated during the previous pass.
+
+It is at this stage that C<split()> silently optimizes C</^/> to
+mean C</^/m>.
+
+=back
+
+=head2 I/O Operators
+X<operator, i/o> X<operator, io> X<io> X<while> X<filehandle>
+X<< <> >> X<@ARGV>
+
+There are several I/O operators you should know about.
+
+A string enclosed by backticks (grave accents) first undergoes
+double-quote interpolation. It is then interpreted as an external
+command, and the output of that command is the value of the
+backtick string, like in a shell. In scalar context, a single string
+consisting of all output is returned. In list context, a list of
+values is returned, one per line of output. (You can set C<$/> to use
+a different line terminator.) The command is executed each time the
+pseudo-literal is evaluated. The status value of the command is
+returned in C<$?> (see L<perlvar> for the interpretation of C<$?>).
+Unlike in B<csh>, no translation is done on the return data--newlines
+remain newlines. Unlike in any of the shells, single quotes do not
+hide variable names in the command from interpretation. To pass a
+literal dollar-sign through to the shell you need to hide it with a
+backslash. The generalized form of backticks is C<qx//>. (Because
+backticks always undergo shell expansion as well, see L<perlsec> for
+security concerns.)
+X<qx> X<`> X<``> X<backtick> X<glob>
+
+In scalar context, evaluating a filehandle in angle brackets yields
+the next line from that file (the newline, if any, included), or
+C<undef> at end-of-file or on error. When C<$/> is set to C<undef>
+(sometimes known as file-slurp mode) and the file is empty, it
+returns C<''> the first time, followed by C<undef> subsequently.
+
+Ordinarily you must assign the returned value to a variable, but
+there is one situation where an automatic assignment happens. If
+and only if the input symbol is the only thing inside the conditional
+of a C<while> statement (even if disguised as a C<for(;;)> loop),
+the value is automatically assigned to the global variable $_,
+destroying whatever was there previously. (This may seem like an
+odd thing to you, but you'll use the construct in almost every Perl
+script you write.) The $_ variable is not implicitly localized.
+You'll have to put a C<local $_;> before the loop if you want that
+to happen.
+
+The following lines are equivalent:
+
+ while (defined($_ = <STDIN>)) { print; }
+ while ($_ = <STDIN>) { print; }
+ while (<STDIN>) { print; }
+ for (;<STDIN>;) { print; }
+ print while defined($_ = <STDIN>);
+ print while ($_ = <STDIN>);
+ print while <STDIN>;
+
+This also behaves similarly, but avoids $_ :
+
+ while (my $line = <STDIN>) { print $line }
+
+In these loop constructs, the assigned value (whether assignment
+is automatic or explicit) is then tested to see whether it is
+defined. The defined test avoids problems where line has a string
+value that would be treated as false by Perl, for example a "" or
+a "0" with no trailing newline. If you really mean for such values
+to terminate the loop, they should be tested for explicitly:
+
+ while (($_ = <STDIN>) ne '0') { ... }
+ while (<STDIN>) { last unless $_; ... }
+
+In other boolean contexts, C<< <filehandle> >> without an
+explicit C<defined> test or comparison elicits a warning if the
+C<use warnings> pragma or the B<-w>
+command-line switch (the C<$^W> variable) is in effect.
+
+The filehandles STDIN, STDOUT, and STDERR are predefined. (The
+filehandles C<stdin>, C<stdout>, and C<stderr> will also work except
+in packages, where they would be interpreted as local identifiers
+rather than global.) Additional filehandles may be created with
+the open() function, amongst others. See L<perlopentut> and
+L<perlfunc/open> for details on this.
+X<stdin> X<stdout> X<sterr>
+
+If a <FILEHANDLE> is used in a context that is looking for
+a list, a list comprising all input lines is returned, one line per
+list element. It's easy to grow to a rather large data space this
+way, so use with care.
+
+<FILEHANDLE> may also be spelled C<readline(*FILEHANDLE)>.
+See L<perlfunc/readline>.
+
+The null filehandle <> is special: it can be used to emulate the
+behavior of B<sed> and B<awk>. Input from <> comes either from
+standard input, or from each file listed on the command line. Here's
+how it works: the first time <> is evaluated, the @ARGV array is
+checked, and if it is empty, C<$ARGV[0]> is set to "-", which when opened
+gives you standard input. The @ARGV array is then processed as a list
+of filenames. The loop
+
+ while (<>) {
+ ... # code for each line
+ }
+
+is equivalent to the following Perl-like pseudo code:
+
+ unshift(@ARGV, '-') unless @ARGV;
+ while ($ARGV = shift) {
+ open(ARGV, $ARGV);
+ while (<ARGV>) {
+ ... # code for each line
+ }
+ }
+
+except that it isn't so cumbersome to say, and will actually work.
+It really does shift the @ARGV array and put the current filename
+into the $ARGV variable. It also uses filehandle I<ARGV>
+internally. <> is just a synonym for <ARGV>, which
+is magical. (The pseudo code above doesn't work because it treats
+<ARGV> as non-magical.)
+
+Since the null filehandle uses the two argument form of L<perlfunc/open>
+it interprets special characters, so if you have a script like this:
+
+ while (<>) {
+ print;
+ }
+
+and call it with C<perl dangerous.pl 'rm -rfv *|'>, it actually opens a
+pipe, executes the C<rm> command and reads C<rm>'s output from that pipe.
+If you want all items in C<@ARGV> to be interpreted as file names, you
+can use the module C<ARGV::readonly> from CPAN.
+
+You can modify @ARGV before the first <> as long as the array ends up
+containing the list of filenames you really want. Line numbers (C<$.>)
+continue as though the input were one big happy file. See the example
+in L<perlfunc/eof> for how to reset line numbers on each file.
+
+If you want to set @ARGV to your own list of files, go right ahead.
+This sets @ARGV to all plain text files if no @ARGV was given:
+
+ @ARGV = grep { -f && -T } glob('*') unless @ARGV;
+
+You can even set them to pipe commands. For example, this automatically
+filters compressed arguments through B<gzip>:
+
+ @ARGV = map { /\.(gz|Z)$/ ? "gzip -dc < $_ |" : $_ } @ARGV;
+
+If you want to pass switches into your script, you can use one of the
+Getopts modules or put a loop on the front like this:
+
+ while ($_ = $ARGV[0], /^-/) {
+ shift;
+ last if /^--$/;
+ if (/^-D(.*)/) { $debug = $1 }
+ if (/^-v/) { $verbose++ }
+ # ... # other switches
+ }
+
+ while (<>) {
+ # ... # code for each line
+ }
+
+The <> symbol will return C<undef> for end-of-file only once.
+If you call it again after this, it will assume you are processing another
+@ARGV list, and if you haven't set @ARGV, will read input from STDIN.
+
+If what the angle brackets contain is a simple scalar variable (e.g.,
+<$foo>), then that variable contains the name of the
+filehandle to input from, or its typeglob, or a reference to the
+same. For example:
+
+ $fh = \*STDIN;
+ $line = <$fh>;
+
+If what's within the angle brackets is neither a filehandle nor a simple
+scalar variable containing a filehandle name, typeglob, or typeglob
+reference, it is interpreted as a filename pattern to be globbed, and
+either a list of filenames or the next filename in the list is returned,
+depending on context. This distinction is determined on syntactic
+grounds alone. That means C<< <$x> >> is always a readline() from
+an indirect handle, but C<< <$hash{key}> >> is always a glob().
+That's because $x is a simple scalar variable, but C<$hash{key}> is
+not--it's a hash element. Even C<< <$x > >> (note the extra space)
+is treated as C<glob("$x ")>, not C<readline($x)>.
+
+One level of double-quote interpretation is done first, but you can't
+say C<< <$foo> >> because that's an indirect filehandle as explained
+in the previous paragraph. (In older versions of Perl, programmers
+would insert curly brackets to force interpretation as a filename glob:
+C<< <${foo}> >>. These days, it's considered cleaner to call the
+internal function directly as C<glob($foo)>, which is probably the right
+way to have done it in the first place.) For example:
+
+ while (<*.c>) {
+ chmod 0644, $_;
+ }
+
+is roughly equivalent to:
+
+ open(FOO, "echo *.c | tr -s ' \t\r\f' '\\012\\012\\012\\012'|");
+ while (<FOO>) {
+ chomp;
+ chmod 0644, $_;
+ }
+
+except that the globbing is actually done internally using the standard
+C<File::Glob> extension. Of course, the shortest way to do the above is:
+
+ chmod 0644, <*.c>;
+
+A (file)glob evaluates its (embedded) argument only when it is
+starting a new list. All values must be read before it will start
+over. In list context, this isn't important because you automatically
+get them all anyway. However, in scalar context the operator returns
+the next value each time it's called, or C<undef> when the list has
+run out. As with filehandle reads, an automatic C<defined> is
+generated when the glob occurs in the test part of a C<while>,
+because legal glob returns (e.g. a file called F<0>) would otherwise
+terminate the loop. Again, C<undef> is returned only once. So if
+you're expecting a single value from a glob, it is much better to
+say
+
+ ($file) = <blurch*>;
+
+than
+
+ $file = <blurch*>;
+
+because the latter will alternate between returning a filename and
+returning false.
+
+If you're trying to do variable interpolation, it's definitely better
+to use the glob() function, because the older notation can cause people
+to become confused with the indirect filehandle notation.
+
+ @files = glob("$dir/*.[ch]");
+ @files = glob($files[$i]);
+
+=head2 Constant Folding
+X<constant folding> X<folding>
+
+Like C, Perl does a certain amount of expression evaluation at
+compile time whenever it determines that all arguments to an
+operator are static and have no side effects. In particular, string
+concatenation happens at compile time between literals that don't do
+variable substitution. Backslash interpolation also happens at
+compile time. You can say
+
+ 'Now is the time for all' . "\n" .
+ 'good men to come to.'
+
+and this all reduces to one string internally. Likewise, if
+you say
+
+ foreach $file (@filenames) {
+ if (-s $file > 5 + 100 * 2**16) { }
+ }
+
+the compiler will precompute the number which that expression
+represents so that the interpreter won't have to.
+
+=head2 No-ops
+X<no-op> X<nop>
+
+Perl doesn't officially have a no-op operator, but the bare constants
+C<0> and C<1> are special-cased to not produce a warning in a void
+context, so you can for example safely do
+
+ 1 while foo();
+
+=head2 Bitwise String Operators
+X<operator, bitwise, string>
+
+Bitstrings of any size may be manipulated by the bitwise operators
+(C<~ | & ^>).
+
+If the operands to a binary bitwise op are strings of different
+sizes, B<|> and B<^> ops act as though the shorter operand had
+additional zero bits on the right, while the B<&> op acts as though
+the longer operand were truncated to the length of the shorter.
+The granularity for such extension or truncation is one or more
+bytes.
+
+ # ASCII-based examples
+ print "j p \n" ^ " a h"; # prints "JAPH\n"
+ print "JA" | " ph\n"; # prints "japh\n"
+ print "japh\nJunk" & '_____'; # prints "JAPH\n";
+ print 'p N$' ^ " E<H\n"; # prints "Perl\n";
+
+If you are intending to manipulate bitstrings, be certain that
+you're supplying bitstrings: If an operand is a number, that will imply
+a B<numeric> bitwise operation. You may explicitly show which type of
+operation you intend by using C<""> or C<0+>, as in the examples below.
+
+ $foo = 150 | 105; # yields 255 (0x96 | 0x69 is 0xFF)
+ $foo = '150' | 105; # yields 255
+ $foo = 150 | '105'; # yields 255
+ $foo = '150' | '105'; # yields string '155' (under ASCII)
+
+ $baz = 0+$foo & 0+$bar; # both ops explicitly numeric
+ $biz = "$foo" ^ "$bar"; # both ops explicitly stringy
+
+See L<perlfunc/vec> for information on how to manipulate individual bits
+in a bit vector.
+
+=head2 Integer Arithmetic
+X<integer>
+
+By default, Perl assumes that it must do most of its arithmetic in
+floating point. But by saying
+
+ use integer;
+
+you may tell the compiler that it's okay to use integer operations
+(if it feels like it) from here to the end of the enclosing BLOCK.
+An inner BLOCK may countermand this by saying
+
+ no integer;
+
+which lasts until the end of that BLOCK. Note that this doesn't
+mean everything is only an integer, merely that Perl may use integer
+operations if it is so inclined. For example, even under C<use
+integer>, if you take the C<sqrt(2)>, you'll still get C<1.4142135623731>
+or so.
+
+Used on numbers, the bitwise operators ("&", "|", "^", "~", "<<",
+and ">>") always produce integral results. (But see also
+L<Bitwise String Operators>.) However, C<use integer> still has meaning for
+them. By default, their results are interpreted as unsigned integers, but
+if C<use integer> is in effect, their results are interpreted
+as signed integers. For example, C<~0> usually evaluates to a large
+integral value. However, C<use integer; ~0> is C<-1> on two's-complement
+machines.
+
+=head2 Floating-point Arithmetic
+X<floating-point> X<floating point> X<float> X<real>
+
+While C<use integer> provides integer-only arithmetic, there is no
+analogous mechanism to provide automatic rounding or truncation to a
+certain number of decimal places. For rounding to a certain number
+of digits, sprintf() or printf() is usually the easiest route.
+See L<perlfaq4>.
+
+Floating-point numbers are only approximations to what a mathematician
+would call real numbers. There are infinitely more reals than floats,
+so some corners must be cut. For example:
+
+ printf "%.20g\n", 123456789123456789;
+ # produces 123456789123456784
+
+Testing for exact floating-point equality or inequality is not a
+good idea. Here's a (relatively expensive) work-around to compare
+whether two floating-point numbers are equal to a particular number of
+decimal places. See Knuth, volume II, for a more robust treatment of
+this topic.
+
+ sub fp_equal {
+ my ($X, $Y, $POINTS) = @_;
+ my ($tX, $tY);
+ $tX = sprintf("%.${POINTS}g", $X);
+ $tY = sprintf("%.${POINTS}g", $Y);
+ return $tX eq $tY;
+ }
+
+The POSIX module (part of the standard perl distribution) implements
+ceil(), floor(), and other mathematical and trigonometric functions.
+The Math::Complex module (part of the standard perl distribution)
+defines mathematical functions that work on both the reals and the
+imaginary numbers. Math::Complex not as efficient as POSIX, but
+POSIX can't work with complex numbers.
+
+Rounding in financial applications can have serious implications, and
+the rounding method used should be specified precisely. In these
+cases, it probably pays not to trust whichever system rounding is
+being used by Perl, but to instead implement the rounding function you
+need yourself.
+
+=head2 Bigger Numbers
+X<number, arbitrary precision>
+
+The standard Math::BigInt and Math::BigFloat modules provide
+variable-precision arithmetic and overloaded operators, although
+they're currently pretty slow. At the cost of some space and
+considerable speed, they avoid the normal pitfalls associated with
+limited-precision representations.
+
+ use Math::BigInt;
+ $x = Math::BigInt->new('123456789123456789');
+ print $x * $x;
+
+ # prints +15241578780673678515622620750190521
+
+There are several modules that let you calculate with (bound only by
+memory and cpu-time) unlimited or fixed precision. There are also
+some non-standard modules that provide faster implementations via
+external C libraries.
+
+Here is a short, but incomplete summary:
+
+ Math::Fraction big, unlimited fractions like 9973 / 12967
+ Math::String treat string sequences like numbers
+ Math::FixedPrecision calculate with a fixed precision
+ Math::Currency for currency calculations
+ Bit::Vector manipulate bit vectors fast (uses C)
+ Math::BigIntFast Bit::Vector wrapper for big numbers
+ Math::Pari provides access to the Pari C library
+ Math::BigInteger uses an external C library
+ Math::Cephes uses external Cephes C library (no big numbers)
+ Math::Cephes::Fraction fractions via the Cephes library
+ Math::GMP another one using an external C library
+
+Choose wisely.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlopenbsd.pod b/Master/tlpkg/tlperl/lib/pods/perlopenbsd.pod
new file mode 100644
index 00000000000..b1d5eea14f4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlopenbsd.pod
@@ -0,0 +1,30 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.openbsd - Perl version 5 on OpenBSD systems
+
+=head1 DESCRIPTION
+
+This document describes various features of OpenBSD that will affect how Perl
+version 5 (hereafter just Perl) is compiled and/or runs.
+
+=head2 OpenBSD core dumps from getprotobyname_r and getservbyname_r with ithreads
+
+When Perl is configured to use ithreads, it will use re-entrant library calls
+in preference to non-re-entrant versions. There is an incompatability in
+OpenBSD's C<getprotobyname_r> and C<getservbyname_r> function in versions 3.7
+and later that will cause a SEGV when called without doing a C<bzero> on
+their return structs prior to calling these functions. Current Perl's
+should handle this problem correctly. Older threaded Perls (5.8.6 or earlier)
+will run into this problem. If you want to run a threaded Perl on OpenBSD
+3.7 or higher, you will need to upgrade to at least Perl 5.8.7.
+
+=head1 AUTHOR
+
+Steve Peters <steve@fisharerojo.org>
+
+Please report any errors, updates, or suggestions to F<perlbug@perl.org>.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlopentut.pod b/Master/tlpkg/tlperl/lib/pods/perlopentut.pod
new file mode 100644
index 00000000000..ea4b307b459
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlopentut.pod
@@ -0,0 +1,981 @@
+=head1 NAME
+
+perlopentut - tutorial on opening things in Perl
+
+=head1 DESCRIPTION
+
+Perl has two simple, built-in ways to open files: the shell way for
+convenience, and the C way for precision. The shell way also has 2- and
+3-argument forms, which have different semantics for handling the filename.
+The choice is yours.
+
+=head1 Open E<agrave> la shell
+
+Perl's C<open> function was designed to mimic the way command-line
+redirection in the shell works. Here are some basic examples
+from the shell:
+
+ $ myprogram file1 file2 file3
+ $ myprogram < inputfile
+ $ myprogram > outputfile
+ $ myprogram >> outputfile
+ $ myprogram | otherprogram
+ $ otherprogram | myprogram
+
+And here are some more advanced examples:
+
+ $ otherprogram | myprogram f1 - f2
+ $ otherprogram 2>&1 | myprogram -
+ $ myprogram <&3
+ $ myprogram >&4
+
+Programmers accustomed to constructs like those above can take comfort
+in learning that Perl directly supports these familiar constructs using
+virtually the same syntax as the shell.
+
+=head2 Simple Opens
+
+The C<open> function takes two arguments: the first is a filehandle,
+and the second is a single string comprising both what to open and how
+to open it. C<open> returns true when it works, and when it fails,
+returns a false value and sets the special variable C<$!> to reflect
+the system error. If the filehandle was previously opened, it will
+be implicitly closed first.
+
+For example:
+
+ open(INFO, "datafile") || die("can't open datafile: $!");
+ open(INFO, "< datafile") || die("can't open datafile: $!");
+ open(RESULTS,"> runstats") || die("can't open runstats: $!");
+ open(LOG, ">> logfile ") || die("can't open logfile: $!");
+
+If you prefer the low-punctuation version, you could write that this way:
+
+ open INFO, "< datafile" or die "can't open datafile: $!";
+ open RESULTS,"> runstats" or die "can't open runstats: $!";
+ open LOG, ">> logfile " or die "can't open logfile: $!";
+
+A few things to notice. First, the leading less-than is optional.
+If omitted, Perl assumes that you want to open the file for reading.
+
+Note also that the first example uses the C<||> logical operator, and the
+second uses C<or>, which has lower precedence. Using C<||> in the latter
+examples would effectively mean
+
+ open INFO, ( "< datafile" || die "can't open datafile: $!" );
+
+which is definitely not what you want.
+
+The other important thing to notice is that, just as in the shell,
+any whitespace before or after the filename is ignored. This is good,
+because you wouldn't want these to do different things:
+
+ open INFO, "<datafile"
+ open INFO, "< datafile"
+ open INFO, "< datafile"
+
+Ignoring surrounding whitespace also helps for when you read a filename
+in from a different file, and forget to trim it before opening:
+
+ $filename = <INFO>; # oops, \n still there
+ open(EXTRA, "< $filename") || die "can't open $filename: $!";
+
+This is not a bug, but a feature. Because C<open> mimics the shell in
+its style of using redirection arrows to specify how to open the file, it
+also does so with respect to extra whitespace around the filename itself
+as well. For accessing files with naughty names, see
+L<"Dispelling the Dweomer">.
+
+There is also a 3-argument version of C<open>, which lets you put the
+special redirection characters into their own argument:
+
+ open( INFO, ">", $datafile ) || die "Can't create $datafile: $!";
+
+In this case, the filename to open is the actual string in C<$datafile>,
+so you don't have to worry about C<$datafile> containing characters
+that might influence the open mode, or whitespace at the beginning of
+the filename that would be absorbed in the 2-argument version. Also,
+any reduction of unnecessary string interpolation is a good thing.
+
+=head2 Indirect Filehandles
+
+C<open>'s first argument can be a reference to a filehandle. As of
+perl 5.6.0, if the argument is uninitialized, Perl will automatically
+create a filehandle and put a reference to it in the first argument,
+like so:
+
+ open( my $in, $infile ) or die "Couldn't read $infile: $!";
+ while ( <$in> ) {
+ # do something with $_
+ }
+ close $in;
+
+Indirect filehandles make namespace management easier. Since filehandles
+are global to the current package, two subroutines trying to open
+C<INFILE> will clash. With two functions opening indirect filehandles
+like C<my $infile>, there's no clash and no need to worry about future
+conflicts.
+
+Another convenient behavior is that an indirect filehandle automatically
+closes when it goes out of scope or when you undefine it:
+
+ sub firstline {
+ open( my $in, shift ) && return scalar <$in>;
+ # no close() required
+ }
+
+=head2 Pipe Opens
+
+In C, when you want to open a file using the standard I/O library,
+you use the C<fopen> function, but when opening a pipe, you use the
+C<popen> function. But in the shell, you just use a different redirection
+character. That's also the case for Perl. The C<open> call
+remains the same--just its argument differs.
+
+If the leading character is a pipe symbol, C<open> starts up a new
+command and opens a write-only filehandle leading into that command.
+This lets you write into that handle and have what you write show up on
+that command's standard input. For example:
+
+ open(PRINTER, "| lpr -Plp1") || die "can't run lpr: $!";
+ print PRINTER "stuff\n";
+ close(PRINTER) || die "can't close lpr: $!";
+
+If the trailing character is a pipe, you start up a new command and open a
+read-only filehandle leading out of that command. This lets whatever that
+command writes to its standard output show up on your handle for reading.
+For example:
+
+ open(NET, "netstat -i -n |") || die "can't fork netstat: $!";
+ while (<NET>) { } # do something with input
+ close(NET) || die "can't close netstat: $!";
+
+What happens if you try to open a pipe to or from a non-existent
+command? If possible, Perl will detect the failure and set C<$!> as
+usual. But if the command contains special shell characters, such as
+C<E<gt>> or C<*>, called 'metacharacters', Perl does not execute the
+command directly. Instead, Perl runs the shell, which then tries to
+run the command. This means that it's the shell that gets the error
+indication. In such a case, the C<open> call will only indicate
+failure if Perl can't even run the shell. See L<perlfaq8/"How can I
+capture STDERR from an external command?"> to see how to cope with
+this. There's also an explanation in L<perlipc>.
+
+If you would like to open a bidirectional pipe, the IPC::Open2
+library will handle this for you. Check out
+L<perlipc/"Bidirectional Communication with Another Process">
+
+perl-5.6.x introduced a version of piped open that executes a process
+based on its command line arguments without relying on the shell. (Similar
+to the C<system(@LIST)> notation.) This is safer and faster than executing
+a single argument pipe-command, but does not allow special shell
+constructs. (It is also not supported on Microsoft Windows, Mac OS Classic
+or RISC OS.)
+
+Here's an example of C<open '-|'>, which prints a random Unix
+fortune cookie as uppercase:
+
+ my $collection = shift(@ARGV);
+ open my $fortune, '-|', 'fortune', $collection
+ or die "Could not find fortune - $!";
+ while (<$fortune>)
+ {
+ print uc($_);
+ }
+ close($fortune);
+
+And this C<open '|-'> pipes into lpr:
+
+ open my $printer, '|-', 'lpr', '-Plp1'
+ or die "can't run lpr: $!";
+ print {$printer} "stuff\n";
+ close($printer)
+ or die "can't close lpr: $!";
+
+=head2 The Minus File
+
+Again following the lead of the standard shell utilities, Perl's
+C<open> function treats a file whose name is a single minus, "-", in a
+special way. If you open minus for reading, it really means to access
+the standard input. If you open minus for writing, it really means to
+access the standard output.
+
+If minus can be used as the default input or default output, what happens
+if you open a pipe into or out of minus? What's the default command it
+would run? The same script as you're currently running! This is actually
+a stealth C<fork> hidden inside an C<open> call. See
+L<perlipc/"Safe Pipe Opens"> for details.
+
+=head2 Mixing Reads and Writes
+
+It is possible to specify both read and write access. All you do is
+add a "+" symbol in front of the redirection. But as in the shell,
+using a less-than on a file never creates a new file; it only opens an
+existing one. On the other hand, using a greater-than always clobbers
+(truncates to zero length) an existing file, or creates a brand-new one
+if there isn't an old one. Adding a "+" for read-write doesn't affect
+whether it only works on existing files or always clobbers existing ones.
+
+ open(WTMP, "+< /usr/adm/wtmp")
+ || die "can't open /usr/adm/wtmp: $!";
+
+ open(SCREEN, "+> lkscreen")
+ || die "can't open lkscreen: $!";
+
+ open(LOGFILE, "+>> /var/log/applog")
+ || die "can't open /var/log/applog: $!";
+
+The first one won't create a new file, and the second one will always
+clobber an old one. The third one will create a new file if necessary
+and not clobber an old one, and it will allow you to read at any point
+in the file, but all writes will always go to the end. In short,
+the first case is substantially more common than the second and third
+cases, which are almost always wrong. (If you know C, the plus in
+Perl's C<open> is historically derived from the one in C's fopen(3S),
+which it ultimately calls.)
+
+In fact, when it comes to updating a file, unless you're working on
+a binary file as in the WTMP case above, you probably don't want to
+use this approach for updating. Instead, Perl's B<-i> flag comes to
+the rescue. The following command takes all the C, C++, or yacc source
+or header files and changes all their foo's to bar's, leaving
+the old version in the original filename with a ".orig" tacked
+on the end:
+
+ $ perl -i.orig -pe 's/\bfoo\b/bar/g' *.[Cchy]
+
+This is a short cut for some renaming games that are really
+the best way to update textfiles. See the second question in
+L<perlfaq5> for more details.
+
+=head2 Filters
+
+One of the most common uses for C<open> is one you never
+even notice. When you process the ARGV filehandle using
+C<< <ARGV> >>, Perl actually does an implicit open
+on each file in @ARGV. Thus a program called like this:
+
+ $ myprogram file1 file2 file3
+
+can have all its files opened and processed one at a time
+using a construct no more complex than:
+
+ while (<>) {
+ # do something with $_
+ }
+
+If @ARGV is empty when the loop first begins, Perl pretends you've opened
+up minus, that is, the standard input. In fact, $ARGV, the currently
+open file during C<< <ARGV> >> processing, is even set to "-"
+in these circumstances.
+
+You are welcome to pre-process your @ARGV before starting the loop to
+make sure it's to your liking. One reason to do this might be to remove
+command options beginning with a minus. While you can always roll the
+simple ones by hand, the Getopts modules are good for this:
+
+ use Getopt::Std;
+
+ # -v, -D, -o ARG, sets $opt_v, $opt_D, $opt_o
+ getopts("vDo:");
+
+ # -v, -D, -o ARG, sets $args{v}, $args{D}, $args{o}
+ getopts("vDo:", \%args);
+
+Or the standard Getopt::Long module to permit named arguments:
+
+ use Getopt::Long;
+ GetOptions( "verbose" => \$verbose, # --verbose
+ "Debug" => \$debug, # --Debug
+ "output=s" => \$output );
+ # --output=somestring or --output somestring
+
+Another reason for preprocessing arguments is to make an empty
+argument list default to all files:
+
+ @ARGV = glob("*") unless @ARGV;
+
+You could even filter out all but plain, text files. This is a bit
+silent, of course, and you might prefer to mention them on the way.
+
+ @ARGV = grep { -f && -T } @ARGV;
+
+If you're using the B<-n> or B<-p> command-line options, you
+should put changes to @ARGV in a C<BEGIN{}> block.
+
+Remember that a normal C<open> has special properties, in that it might
+call fopen(3S) or it might called popen(3S), depending on what its
+argument looks like; that's why it's sometimes called "magic open".
+Here's an example:
+
+ $pwdinfo = `domainname` =~ /^(\(none\))?$/
+ ? '< /etc/passwd'
+ : 'ypcat passwd |';
+
+ open(PWD, $pwdinfo)
+ or die "can't open $pwdinfo: $!";
+
+This sort of thing also comes into play in filter processing. Because
+C<< <ARGV> >> processing employs the normal, shell-style Perl C<open>,
+it respects all the special things we've already seen:
+
+ $ myprogram f1 "cmd1|" - f2 "cmd2|" f3 < tmpfile
+
+That program will read from the file F<f1>, the process F<cmd1>, standard
+input (F<tmpfile> in this case), the F<f2> file, the F<cmd2> command,
+and finally the F<f3> file.
+
+Yes, this also means that if you have files named "-" (and so on) in
+your directory, they won't be processed as literal files by C<open>.
+You'll need to pass them as "./-", much as you would for the I<rm> program,
+or you could use C<sysopen> as described below.
+
+One of the more interesting applications is to change files of a certain
+name into pipes. For example, to autoprocess gzipped or compressed
+files by decompressing them with I<gzip>:
+
+ @ARGV = map { /\.(gz|Z)$/ ? "gzip -dc $_ |" : $_ } @ARGV;
+
+Or, if you have the I<GET> program installed from LWP,
+you can fetch URLs before processing them:
+
+ @ARGV = map { m#^\w+://# ? "GET $_ |" : $_ } @ARGV;
+
+It's not for nothing that this is called magic C<< <ARGV> >>.
+Pretty nifty, eh?
+
+=head1 Open E<agrave> la C
+
+If you want the convenience of the shell, then Perl's C<open> is
+definitely the way to go. On the other hand, if you want finer precision
+than C's simplistic fopen(3S) provides you should look to Perl's
+C<sysopen>, which is a direct hook into the open(2) system call.
+That does mean it's a bit more involved, but that's the price of
+precision.
+
+C<sysopen> takes 3 (or 4) arguments.
+
+ sysopen HANDLE, PATH, FLAGS, [MASK]
+
+The HANDLE argument is a filehandle just as with C<open>. The PATH is
+a literal path, one that doesn't pay attention to any greater-thans or
+less-thans or pipes or minuses, nor ignore whitespace. If it's there,
+it's part of the path. The FLAGS argument contains one or more values
+derived from the Fcntl module that have been or'd together using the
+bitwise "|" operator. The final argument, the MASK, is optional; if
+present, it is combined with the user's current umask for the creation
+mode of the file. You should usually omit this.
+
+Although the traditional values of read-only, write-only, and read-write
+are 0, 1, and 2 respectively, this is known not to hold true on some
+systems. Instead, it's best to load in the appropriate constants first
+from the Fcntl module, which supplies the following standard flags:
+
+ O_RDONLY Read only
+ O_WRONLY Write only
+ O_RDWR Read and write
+ O_CREAT Create the file if it doesn't exist
+ O_EXCL Fail if the file already exists
+ O_APPEND Append to the file
+ O_TRUNC Truncate the file
+ O_NONBLOCK Non-blocking access
+
+Less common flags that are sometimes available on some operating
+systems include C<O_BINARY>, C<O_TEXT>, C<O_SHLOCK>, C<O_EXLOCK>,
+C<O_DEFER>, C<O_SYNC>, C<O_ASYNC>, C<O_DSYNC>, C<O_RSYNC>,
+C<O_NOCTTY>, C<O_NDELAY> and C<O_LARGEFILE>. Consult your open(2)
+manpage or its local equivalent for details. (Note: starting from
+Perl release 5.6 the C<O_LARGEFILE> flag, if available, is automatically
+added to the sysopen() flags because large files are the default.)
+
+Here's how to use C<sysopen> to emulate the simple C<open> calls we had
+before. We'll omit the C<|| die $!> checks for clarity, but make sure
+you always check the return values in real code. These aren't quite
+the same, since C<open> will trim leading and trailing whitespace,
+but you'll get the idea.
+
+To open a file for reading:
+
+ open(FH, "< $path");
+ sysopen(FH, $path, O_RDONLY);
+
+To open a file for writing, creating a new file if needed or else truncating
+an old file:
+
+ open(FH, "> $path");
+ sysopen(FH, $path, O_WRONLY | O_TRUNC | O_CREAT);
+
+To open a file for appending, creating one if necessary:
+
+ open(FH, ">> $path");
+ sysopen(FH, $path, O_WRONLY | O_APPEND | O_CREAT);
+
+To open a file for update, where the file must already exist:
+
+ open(FH, "+< $path");
+ sysopen(FH, $path, O_RDWR);
+
+And here are things you can do with C<sysopen> that you cannot do with
+a regular C<open>. As you'll see, it's just a matter of controlling the
+flags in the third argument.
+
+To open a file for writing, creating a new file which must not previously
+exist:
+
+ sysopen(FH, $path, O_WRONLY | O_EXCL | O_CREAT);
+
+To open a file for appending, where that file must already exist:
+
+ sysopen(FH, $path, O_WRONLY | O_APPEND);
+
+To open a file for update, creating a new file if necessary:
+
+ sysopen(FH, $path, O_RDWR | O_CREAT);
+
+To open a file for update, where that file must not already exist:
+
+ sysopen(FH, $path, O_RDWR | O_EXCL | O_CREAT);
+
+To open a file without blocking, creating one if necessary:
+
+ sysopen(FH, $path, O_WRONLY | O_NONBLOCK | O_CREAT);
+
+=head2 Permissions E<agrave> la mode
+
+If you omit the MASK argument to C<sysopen>, Perl uses the octal value
+0666. The normal MASK to use for executables and directories should
+be 0777, and for anything else, 0666.
+
+Why so permissive? Well, it isn't really. The MASK will be modified
+by your process's current C<umask>. A umask is a number representing
+I<disabled> permissions bits; that is, bits that will not be turned on
+in the created file's permissions field.
+
+For example, if your C<umask> were 027, then the 020 part would
+disable the group from writing, and the 007 part would disable others
+from reading, writing, or executing. Under these conditions, passing
+C<sysopen> 0666 would create a file with mode 0640, since C<0666 & ~027>
+is 0640.
+
+You should seldom use the MASK argument to C<sysopen()>. That takes
+away the user's freedom to choose what permission new files will have.
+Denying choice is almost always a bad thing. One exception would be for
+cases where sensitive or private data is being stored, such as with mail
+folders, cookie files, and internal temporary files.
+
+=head1 Obscure Open Tricks
+
+=head2 Re-Opening Files (dups)
+
+Sometimes you already have a filehandle open, and want to make another
+handle that's a duplicate of the first one. In the shell, we place an
+ampersand in front of a file descriptor number when doing redirections.
+For example, C<< 2>&1 >> makes descriptor 2 (that's STDERR in Perl)
+be redirected into descriptor 1 (which is usually Perl's STDOUT).
+The same is essentially true in Perl: a filename that begins with an
+ampersand is treated instead as a file descriptor if a number, or as a
+filehandle if a string.
+
+ open(SAVEOUT, ">&SAVEERR") || die "couldn't dup SAVEERR: $!";
+ open(MHCONTEXT, "<&4") || die "couldn't dup fd4: $!";
+
+That means that if a function is expecting a filename, but you don't
+want to give it a filename because you already have the file open, you
+can just pass the filehandle with a leading ampersand. It's best to
+use a fully qualified handle though, just in case the function happens
+to be in a different package:
+
+ somefunction("&main::LOGFILE");
+
+This way if somefunction() is planning on opening its argument, it can
+just use the already opened handle. This differs from passing a handle,
+because with a handle, you don't open the file. Here you have something
+you can pass to open.
+
+If you have one of those tricky, newfangled I/O objects that the C++
+folks are raving about, then this doesn't work because those aren't a
+proper filehandle in the native Perl sense. You'll have to use fileno()
+to pull out the proper descriptor number, assuming you can:
+
+ use IO::Socket;
+ $handle = IO::Socket::INET->new("www.perl.com:80");
+ $fd = $handle->fileno;
+ somefunction("&$fd"); # not an indirect function call
+
+It can be easier (and certainly will be faster) just to use real
+filehandles though:
+
+ use IO::Socket;
+ local *REMOTE = IO::Socket::INET->new("www.perl.com:80");
+ die "can't connect" unless defined(fileno(REMOTE));
+ somefunction("&main::REMOTE");
+
+If the filehandle or descriptor number is preceded not just with a simple
+"&" but rather with a "&=" combination, then Perl will not create a
+completely new descriptor opened to the same place using the dup(2)
+system call. Instead, it will just make something of an alias to the
+existing one using the fdopen(3S) library call. This is slightly more
+parsimonious of systems resources, although this is less a concern
+these days. Here's an example of that:
+
+ $fd = $ENV{"MHCONTEXTFD"};
+ open(MHCONTEXT, "<&=$fd") or die "couldn't fdopen $fd: $!";
+
+If you're using magic C<< <ARGV> >>, you could even pass in as a
+command line argument in @ARGV something like C<"<&=$MHCONTEXTFD">,
+but we've never seen anyone actually do this.
+
+=head2 Dispelling the Dweomer
+
+Perl is more of a DWIMmer language than something like Java--where DWIM
+is an acronym for "do what I mean". But this principle sometimes leads
+to more hidden magic than one knows what to do with. In this way, Perl
+is also filled with I<dweomer>, an obscure word meaning an enchantment.
+Sometimes, Perl's DWIMmer is just too much like dweomer for comfort.
+
+If magic C<open> is a bit too magical for you, you don't have to turn
+to C<sysopen>. To open a file with arbitrary weird characters in
+it, it's necessary to protect any leading and trailing whitespace.
+Leading whitespace is protected by inserting a C<"./"> in front of a
+filename that starts with whitespace. Trailing whitespace is protected
+by appending an ASCII NUL byte (C<"\0">) at the end of the string.
+
+ $file =~ s#^(\s)#./$1#;
+ open(FH, "< $file\0") || die "can't open $file: $!";
+
+This assumes, of course, that your system considers dot the current
+working directory, slash the directory separator, and disallows ASCII
+NULs within a valid filename. Most systems follow these conventions,
+including all POSIX systems as well as proprietary Microsoft systems.
+The only vaguely popular system that doesn't work this way is the
+"Classic" Macintosh system, which uses a colon where the rest of us
+use a slash. Maybe C<sysopen> isn't such a bad idea after all.
+
+If you want to use C<< <ARGV> >> processing in a totally boring
+and non-magical way, you could do this first:
+
+ # "Sam sat on the ground and put his head in his hands.
+ # 'I wish I had never come here, and I don't want to see
+ # no more magic,' he said, and fell silent."
+ for (@ARGV) {
+ s#^([^./])#./$1#;
+ $_ .= "\0";
+ }
+ while (<>) {
+ # now process $_
+ }
+
+But be warned that users will not appreciate being unable to use "-"
+to mean standard input, per the standard convention.
+
+=head2 Paths as Opens
+
+You've probably noticed how Perl's C<warn> and C<die> functions can
+produce messages like:
+
+ Some warning at scriptname line 29, <FH> line 7.
+
+That's because you opened a filehandle FH, and had read in seven records
+from it. But what was the name of the file, rather than the handle?
+
+If you aren't running with C<strict refs>, or if you've turned them off
+temporarily, then all you have to do is this:
+
+ open($path, "< $path") || die "can't open $path: $!";
+ while (<$path>) {
+ # whatever
+ }
+
+Since you're using the pathname of the file as its handle,
+you'll get warnings more like
+
+ Some warning at scriptname line 29, </etc/motd> line 7.
+
+=head2 Single Argument Open
+
+Remember how we said that Perl's open took two arguments? That was a
+passive prevarication. You see, it can also take just one argument.
+If and only if the variable is a global variable, not a lexical, you
+can pass C<open> just one argument, the filehandle, and it will
+get the path from the global scalar variable of the same name.
+
+ $FILE = "/etc/motd";
+ open FILE or die "can't open $FILE: $!";
+ while (<FILE>) {
+ # whatever
+ }
+
+Why is this here? Someone has to cater to the hysterical porpoises.
+It's something that's been in Perl since the very beginning, if not
+before.
+
+=head2 Playing with STDIN and STDOUT
+
+One clever move with STDOUT is to explicitly close it when you're done
+with the program.
+
+ END { close(STDOUT) || die "can't close stdout: $!" }
+
+If you don't do this, and your program fills up the disk partition due
+to a command line redirection, it won't report the error exit with a
+failure status.
+
+You don't have to accept the STDIN and STDOUT you were given. You are
+welcome to reopen them if you'd like.
+
+ open(STDIN, "< datafile")
+ || die "can't open datafile: $!";
+
+ open(STDOUT, "> output")
+ || die "can't open output: $!";
+
+And then these can be accessed directly or passed on to subprocesses.
+This makes it look as though the program were initially invoked
+with those redirections from the command line.
+
+It's probably more interesting to connect these to pipes. For example:
+
+ $pager = $ENV{PAGER} || "(less || more)";
+ open(STDOUT, "| $pager")
+ || die "can't fork a pager: $!";
+
+This makes it appear as though your program were called with its stdout
+already piped into your pager. You can also use this kind of thing
+in conjunction with an implicit fork to yourself. You might do this
+if you would rather handle the post processing in your own program,
+just in a different process:
+
+ head(100);
+ while (<>) {
+ print;
+ }
+
+ sub head {
+ my $lines = shift || 20;
+ return if $pid = open(STDOUT, "|-"); # return if parent
+ die "cannot fork: $!" unless defined $pid;
+ while (<STDIN>) {
+ last if --$lines < 0;
+ print;
+ }
+ exit;
+ }
+
+This technique can be applied to repeatedly push as many filters on your
+output stream as you wish.
+
+=head1 Other I/O Issues
+
+These topics aren't really arguments related to C<open> or C<sysopen>,
+but they do affect what you do with your open files.
+
+=head2 Opening Non-File Files
+
+When is a file not a file? Well, you could say when it exists but
+isn't a plain file. We'll check whether it's a symbolic link first,
+just in case.
+
+ if (-l $file || ! -f _) {
+ print "$file is not a plain file\n";
+ }
+
+What other kinds of files are there than, well, files? Directories,
+symbolic links, named pipes, Unix-domain sockets, and block and character
+devices. Those are all files, too--just not I<plain> files. This isn't
+the same issue as being a text file. Not all text files are plain files.
+Not all plain files are text files. That's why there are separate C<-f>
+and C<-T> file tests.
+
+To open a directory, you should use the C<opendir> function, then
+process it with C<readdir>, carefully restoring the directory
+name if necessary:
+
+ opendir(DIR, $dirname) or die "can't opendir $dirname: $!";
+ while (defined($file = readdir(DIR))) {
+ # do something with "$dirname/$file"
+ }
+ closedir(DIR);
+
+If you want to process directories recursively, it's better to use the
+File::Find module. For example, this prints out all files recursively
+and adds a slash to their names if the file is a directory.
+
+ @ARGV = qw(.) unless @ARGV;
+ use File::Find;
+ find sub { print $File::Find::name, -d && '/', "\n" }, @ARGV;
+
+This finds all bogus symbolic links beneath a particular directory:
+
+ find sub { print "$File::Find::name\n" if -l && !-e }, $dir;
+
+As you see, with symbolic links, you can just pretend that it is
+what it points to. Or, if you want to know I<what> it points to, then
+C<readlink> is called for:
+
+ if (-l $file) {
+ if (defined($whither = readlink($file))) {
+ print "$file points to $whither\n";
+ } else {
+ print "$file points nowhere: $!\n";
+ }
+ }
+
+=head2 Opening Named Pipes
+
+Named pipes are a different matter. You pretend they're regular files,
+but their opens will normally block until there is both a reader and
+a writer. You can read more about them in L<perlipc/"Named Pipes">.
+Unix-domain sockets are rather different beasts as well; they're
+described in L<perlipc/"Unix-Domain TCP Clients and Servers">.
+
+When it comes to opening devices, it can be easy and it can be tricky.
+We'll assume that if you're opening up a block device, you know what
+you're doing. The character devices are more interesting. These are
+typically used for modems, mice, and some kinds of printers. This is
+described in L<perlfaq8/"How do I read and write the serial port?">
+It's often enough to open them carefully:
+
+ sysopen(TTYIN, "/dev/ttyS1", O_RDWR | O_NDELAY | O_NOCTTY)
+ # (O_NOCTTY no longer needed on POSIX systems)
+ or die "can't open /dev/ttyS1: $!";
+ open(TTYOUT, "+>&TTYIN")
+ or die "can't dup TTYIN: $!";
+
+ $ofh = select(TTYOUT); $| = 1; select($ofh);
+
+ print TTYOUT "+++at\015";
+ $answer = <TTYIN>;
+
+With descriptors that you haven't opened using C<sysopen>, such as
+sockets, you can set them to be non-blocking using C<fcntl>:
+
+ use Fcntl;
+ my $old_flags = fcntl($handle, F_GETFL, 0)
+ or die "can't get flags: $!";
+ fcntl($handle, F_SETFL, $old_flags | O_NONBLOCK)
+ or die "can't set non blocking: $!";
+
+Rather than losing yourself in a morass of twisting, turning C<ioctl>s,
+all dissimilar, if you're going to manipulate ttys, it's best to
+make calls out to the stty(1) program if you have it, or else use the
+portable POSIX interface. To figure this all out, you'll need to read the
+termios(3) manpage, which describes the POSIX interface to tty devices,
+and then L<POSIX>, which describes Perl's interface to POSIX. There are
+also some high-level modules on CPAN that can help you with these games.
+Check out Term::ReadKey and Term::ReadLine.
+
+=head2 Opening Sockets
+
+What else can you open? To open a connection using sockets, you won't use
+one of Perl's two open functions. See
+L<perlipc/"Sockets: Client/Server Communication"> for that. Here's an
+example. Once you have it, you can use FH as a bidirectional filehandle.
+
+ use IO::Socket;
+ local *FH = IO::Socket::INET->new("www.perl.com:80");
+
+For opening up a URL, the LWP modules from CPAN are just what
+the doctor ordered. There's no filehandle interface, but
+it's still easy to get the contents of a document:
+
+ use LWP::Simple;
+ $doc = get('http://www.cpan.org/');
+
+=head2 Binary Files
+
+On certain legacy systems with what could charitably be called terminally
+convoluted (some would say broken) I/O models, a file isn't a file--at
+least, not with respect to the C standard I/O library. On these old
+systems whose libraries (but not kernels) distinguish between text and
+binary streams, to get files to behave properly you'll have to bend over
+backwards to avoid nasty problems. On such infelicitous systems, sockets
+and pipes are already opened in binary mode, and there is currently no
+way to turn that off. With files, you have more options.
+
+Another option is to use the C<binmode> function on the appropriate
+handles before doing regular I/O on them:
+
+ binmode(STDIN);
+ binmode(STDOUT);
+ while (<STDIN>) { print }
+
+Passing C<sysopen> a non-standard flag option will also open the file in
+binary mode on those systems that support it. This is the equivalent of
+opening the file normally, then calling C<binmode> on the handle.
+
+ sysopen(BINDAT, "records.data", O_RDWR | O_BINARY)
+ || die "can't open records.data: $!";
+
+Now you can use C<read> and C<print> on that handle without worrying
+about the non-standard system I/O library breaking your data. It's not
+a pretty picture, but then, legacy systems seldom are. CP/M will be
+with us until the end of days, and after.
+
+On systems with exotic I/O systems, it turns out that, astonishingly
+enough, even unbuffered I/O using C<sysread> and C<syswrite> might do
+sneaky data mutilation behind your back.
+
+ while (sysread(WHENCE, $buf, 1024)) {
+ syswrite(WHITHER, $buf, length($buf));
+ }
+
+Depending on the vicissitudes of your runtime system, even these calls
+may need C<binmode> or C<O_BINARY> first. Systems known to be free of
+such difficulties include Unix, the Mac OS, Plan 9, and Inferno.
+
+=head2 File Locking
+
+In a multitasking environment, you may need to be careful not to collide
+with other processes who want to do I/O on the same files as you
+are working on. You'll often need shared or exclusive locks
+on files for reading and writing respectively. You might just
+pretend that only exclusive locks exist.
+
+Never use the existence of a file C<-e $file> as a locking indication,
+because there is a race condition between the test for the existence of
+the file and its creation. It's possible for another process to create
+a file in the slice of time between your existence check and your attempt
+to create the file. Atomicity is critical.
+
+Perl's most portable locking interface is via the C<flock> function,
+whose simplicity is emulated on systems that don't directly support it
+such as SysV or Windows. The underlying semantics may affect how
+it all works, so you should learn how C<flock> is implemented on your
+system's port of Perl.
+
+File locking I<does not> lock out another process that would like to
+do I/O. A file lock only locks out others trying to get a lock, not
+processes trying to do I/O. Because locks are advisory, if one process
+uses locking and another doesn't, all bets are off.
+
+By default, the C<flock> call will block until a lock is granted.
+A request for a shared lock will be granted as soon as there is no
+exclusive locker. A request for an exclusive lock will be granted as
+soon as there is no locker of any kind. Locks are on file descriptors,
+not file names. You can't lock a file until you open it, and you can't
+hold on to a lock once the file has been closed.
+
+Here's how to get a blocking shared lock on a file, typically used
+for reading:
+
+ use 5.004;
+ use Fcntl qw(:DEFAULT :flock);
+ open(FH, "< filename") or die "can't open filename: $!";
+ flock(FH, LOCK_SH) or die "can't lock filename: $!";
+ # now read from FH
+
+You can get a non-blocking lock by using C<LOCK_NB>.
+
+ flock(FH, LOCK_SH | LOCK_NB)
+ or die "can't lock filename: $!";
+
+This can be useful for producing more user-friendly behaviour by warning
+if you're going to be blocking:
+
+ use 5.004;
+ use Fcntl qw(:DEFAULT :flock);
+ open(FH, "< filename") or die "can't open filename: $!";
+ unless (flock(FH, LOCK_SH | LOCK_NB)) {
+ $| = 1;
+ print "Waiting for lock...";
+ flock(FH, LOCK_SH) or die "can't lock filename: $!";
+ print "got it.\n"
+ }
+ # now read from FH
+
+To get an exclusive lock, typically used for writing, you have to be
+careful. We C<sysopen> the file so it can be locked before it gets
+emptied. You can get a nonblocking version using C<LOCK_EX | LOCK_NB>.
+
+ use 5.004;
+ use Fcntl qw(:DEFAULT :flock);
+ sysopen(FH, "filename", O_WRONLY | O_CREAT)
+ or die "can't open filename: $!";
+ flock(FH, LOCK_EX)
+ or die "can't lock filename: $!";
+ truncate(FH, 0)
+ or die "can't truncate filename: $!";
+ # now write to FH
+
+Finally, due to the uncounted millions who cannot be dissuaded from
+wasting cycles on useless vanity devices called hit counters, here's
+how to increment a number in a file safely:
+
+ use Fcntl qw(:DEFAULT :flock);
+
+ sysopen(FH, "numfile", O_RDWR | O_CREAT)
+ or die "can't open numfile: $!";
+ # autoflush FH
+ $ofh = select(FH); $| = 1; select ($ofh);
+ flock(FH, LOCK_EX)
+ or die "can't write-lock numfile: $!";
+
+ $num = <FH> || 0;
+ seek(FH, 0, 0)
+ or die "can't rewind numfile : $!";
+ print FH $num+1, "\n"
+ or die "can't write numfile: $!";
+
+ truncate(FH, tell(FH))
+ or die "can't truncate numfile: $!";
+ close(FH)
+ or die "can't close numfile: $!";
+
+=head2 IO Layers
+
+In Perl 5.8.0 a new I/O framework called "PerlIO" was introduced.
+This is a new "plumbing" for all the I/O happening in Perl; for the
+most part everything will work just as it did, but PerlIO also brought
+in some new features such as the ability to think of I/O as "layers".
+One I/O layer may in addition to just moving the data also do
+transformations on the data. Such transformations may include
+compression and decompression, encryption and decryption, and transforming
+between various character encodings.
+
+Full discussion about the features of PerlIO is out of scope for this
+tutorial, but here is how to recognize the layers being used:
+
+=over 4
+
+=item *
+
+The three-(or more)-argument form of C<open> is being used and the
+second argument contains something else in addition to the usual
+C<< '<' >>, C<< '>' >>, C<< '>>' >>, C<< '|' >> and their variants,
+for example:
+
+ open(my $fh, "<:crlf", $fn);
+
+=item *
+
+The two-argument form of C<binmode> is being used, for example
+
+ binmode($fh, ":encoding(utf16)");
+
+=back
+
+For more detailed discussion about PerlIO see L<PerlIO>;
+for more detailed discussion about Unicode and I/O see L<perluniintro>.
+
+=head1 SEE ALSO
+
+The C<open> and C<sysopen> functions in perlfunc(1);
+the system open(2), dup(2), fopen(3), and fdopen(3) manpages;
+the POSIX documentation.
+
+=head1 AUTHOR and COPYRIGHT
+
+Copyright 1998 Tom Christiansen.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in these files are
+hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun or for profit
+as you see fit. A simple comment in the code giving credit would be
+courteous but is not required.
+
+=head1 HISTORY
+
+First release: Sat Jan 9 08:09:11 MST 1999
diff --git a/Master/tlpkg/tlperl/lib/pods/perlos2.pod b/Master/tlpkg/tlperl/lib/pods/perlos2.pod
new file mode 100644
index 00000000000..1d4083f8d5f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlos2.pod
@@ -0,0 +1,2741 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
+
+=head1 SYNOPSIS
+
+One can read this document in the following formats:
+
+ man perlos2
+ view perl perlos2
+ explorer perlos2.html
+ info perlos2
+
+to list some (not all may be available simultaneously), or it may
+be read I<as is>: either as F<README.os2>, or F<pod/perlos2.pod>.
+
+To read the F<.INF> version of documentation (B<very> recommended)
+outside of OS/2, one needs an IBM's reader (may be available on IBM
+ftp sites (?) (URL anyone?)) or shipped with PC DOS 7.0 and IBM's
+Visual Age C++ 3.5.
+
+A copy of a Win* viewer is contained in the "Just add OS/2 Warp" package
+
+ ftp://ftp.software.ibm.com/ps/products/os2/tools/jaow/jaow.zip
+
+in F<?:\JUST_ADD\view.exe>. This gives one an access to EMX's
+F<.INF> docs as well (text form is available in F</emx/doc> in
+EMX's distribution). There is also a different viewer named xview.
+
+Note that if you have F<lynx.exe> or F<netscape.exe> installed, you can follow WWW links
+from this document in F<.INF> format. If you have EMX docs installed
+correctly, you can follow library links (you need to have C<view emxbook>
+working by setting C<EMXBOOK> environment variable as it is described
+in EMX docs).
+
+=cut
+
+Contents (This may be a little bit obsolete)
+
+ perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
+
+ NAME
+ SYNOPSIS
+ DESCRIPTION
+ - Target
+ - Other OSes
+ - Prerequisites
+ - Starting Perl programs under OS/2 (and DOS and...)
+ - Starting OS/2 (and DOS) programs under Perl
+ Frequently asked questions
+ - "It does not work"
+ - I cannot run external programs
+ - I cannot embed perl into my program, or use perl.dll from my
+ - `` and pipe-open do not work under DOS.
+ - Cannot start find.exe "pattern" file
+ INSTALLATION
+ - Automatic binary installation
+ - Manual binary installation
+ - Warning
+ Accessing documentation
+ - OS/2 .INF file
+ - Plain text
+ - Manpages
+ - HTML
+ - GNU info files
+ - PDF files
+ - LaTeX docs
+ BUILD
+ - The short story
+ - Prerequisites
+ - Getting perl source
+ - Application of the patches
+ - Hand-editing
+ - Making
+ - Testing
+ - Installing the built perl
+ - a.out-style build
+ Build FAQ
+ - Some / became \ in pdksh.
+ - 'errno' - unresolved external
+ - Problems with tr or sed
+ - Some problem (forget which ;-)
+ - Library ... not found
+ - Segfault in make
+ - op/sprintf test failure
+ Specific (mis)features of OS/2 port
+ - setpriority, getpriority
+ - system()
+ - extproc on the first line
+ - Additional modules:
+ - Prebuilt methods:
+ - Prebuilt variables:
+ - Misfeatures
+ - Modifications
+ - Identifying DLLs
+ - Centralized management of resources
+ Perl flavors
+ - perl.exe
+ - perl_.exe
+ - perl__.exe
+ - perl___.exe
+ - Why strange names?
+ - Why dynamic linking?
+ - Why chimera build?
+ ENVIRONMENT
+ - PERLLIB_PREFIX
+ - PERL_BADLANG
+ - PERL_BADFREE
+ - PERL_SH_DIR
+ - USE_PERL_FLOCK
+ - TMP or TEMP
+ Evolution
+ - Text-mode filehandles
+ - Priorities
+ - DLL name mangling: pre 5.6.2
+ - DLL name mangling: 5.6.2 and beyond
+ - DLL forwarder generation
+ - Threading
+ - Calls to external programs
+ - Memory allocation
+ - Threads
+ BUGS
+ AUTHOR
+ SEE ALSO
+
+=head1 DESCRIPTION
+
+=head2 Target
+
+The target is to make OS/2 one of the best supported platform for
+using/building/developing Perl and I<Perl applications>, as well as
+make Perl the best language to use under OS/2. The secondary target is
+to try to make this work under DOS and Win* as well (but not B<too> hard).
+
+The current state is quite close to this target. Known limitations:
+
+=over 5
+
+=item *
+
+Some *nix programs use fork() a lot; with the mostly useful flavors of
+perl for OS/2 (there are several built simultaneously) this is
+supported; but some flavors do not support this (e.g., when Perl is
+called from inside REXX). Using fork() after
+I<use>ing dynamically loading extensions would not work with I<very> old
+versions of EMX.
+
+=item *
+
+You need a separate perl executable F<perl__.exe> (see L<perl__.exe>)
+if you want to use PM code in your application (as Perl/Tk or OpenGL
+Perl modules do) without having a text-mode window present.
+
+While using the standard F<perl.exe> from a text-mode window is possible
+too, I have seen cases when this causes degradation of the system stability.
+Using F<perl__.exe> avoids such a degradation.
+
+=item *
+
+There is no simple way to access WPS objects. The only way I know
+is via C<OS2::REXX> and C<SOM> extensions (see L<OS2::REXX>, L<Som>).
+However, we do not have access to
+convenience methods of Object-REXX. (Is it possible at all? I know
+of no Object-REXX API.) The C<SOM> extension (currently in alpha-text)
+may eventually remove this shortcoming; however, due to the fact that
+DII is not supported by the C<SOM> module, using C<SOM> is not as
+convenient as one would like it.
+
+=back
+
+Please keep this list up-to-date by informing me about other items.
+
+=head2 Other OSes
+
+Since OS/2 port of perl uses a remarkable EMX environment, it can
+run (and build extensions, and - possibly - be built itself) under any
+environment which can run EMX. The current list is DOS,
+DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT. Out of many perl flavors,
+only one works, see L<"perl_.exe">.
+
+Note that not all features of Perl are available under these
+environments. This depends on the features the I<extender> - most
+probably RSX - decided to implement.
+
+Cf. L<Prerequisites>.
+
+=head2 Prerequisites
+
+=over 6
+
+=item EMX
+
+EMX runtime is required (may be substituted by RSX). Note that
+it is possible to make F<perl_.exe> to run under DOS without any
+external support by binding F<emx.exe>/F<rsx.exe> to it, see L<emxbind>. Note
+that under DOS for best results one should use RSX runtime, which
+has much more functions working (like C<fork>, C<popen> and so on). In
+fact RSX is required if there is no VCPI present. Note the
+RSX requires DPMI. Many implementations of DPMI are known to be very
+buggy, beware!
+
+Only the latest runtime is supported, currently C<0.9d fix 03>. Perl may run
+under earlier versions of EMX, but this is not tested.
+
+One can get different parts of EMX from, say
+
+ ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/
+ http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2/dev/emx/v0.9d/
+
+The runtime component should have the name F<emxrt.zip>.
+
+B<NOTE>. When using F<emx.exe>/F<rsx.exe>, it is enough to have them on your path. One
+does not need to specify them explicitly (though this
+
+ emx perl_.exe -de 0
+
+will work as well.)
+
+=item RSX
+
+To run Perl on DPMI platforms one needs RSX runtime. This is
+needed under DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT (see
+L<"Other OSes">). RSX would not work with VCPI
+only, as EMX would, it requires DMPI.
+
+Having RSX and the latest F<sh.exe> one gets a fully functional
+B<*nix>-ish environment under DOS, say, C<fork>, C<``> and
+pipe-C<open> work. In fact, MakeMaker works (for static build), so one
+can have Perl development environment under DOS.
+
+One can get RSX from, say
+
+ http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
+ ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/contrib/
+
+Contact the author on C<rainer@mathematik.uni-bielefeld.de>.
+
+The latest F<sh.exe> with DOS hooks is available in
+
+ http://www.ilyaz.org/software/os2/
+
+as F<sh_dos.zip> or under similar names starting with C<sh>, C<pdksh> etc.
+
+=item HPFS
+
+Perl does not care about file systems, but the perl library contains
+many files with long names, so to install it intact one needs a file
+system which supports long file names.
+
+Note that if you do not plan to build the perl itself, it may be
+possible to fool EMX to truncate file names. This is not supported,
+read EMX docs to see how to do it.
+
+=item pdksh
+
+To start external programs with complicated command lines (like with
+pipes in between, and/or quoting of arguments), Perl uses an external
+shell. With EMX port such shell should be named F<sh.exe>, and located
+either in the wired-in-during-compile locations (usually F<F:/bin>),
+or in configurable location (see L<"PERL_SH_DIR">).
+
+For best results use EMX pdksh. The standard binary (5.2.14 or later) runs
+under DOS (with L<RSX>) as well, see
+
+ http://www.ilyaz.org/software/os2/
+
+=back
+
+=head2 Starting Perl programs under OS/2 (and DOS and...)
+
+Start your Perl program F<foo.pl> with arguments C<arg1 arg2 arg3> the
+same way as on any other platform, by
+
+ perl foo.pl arg1 arg2 arg3
+
+If you want to specify perl options C<-my_opts> to the perl itself (as
+opposed to your program), use
+
+ perl -my_opts foo.pl arg1 arg2 arg3
+
+Alternately, if you use OS/2-ish shell, like CMD or 4os2, put
+the following at the start of your perl script:
+
+ extproc perl -S -my_opts
+
+rename your program to F<foo.cmd>, and start it by typing
+
+ foo arg1 arg2 arg3
+
+Note that because of stupid OS/2 limitations the full path of the perl
+script is not available when you use C<extproc>, thus you are forced to
+use C<-S> perl switch, and your script should be on the C<PATH>. As a plus
+side, if you know a full path to your script, you may still start it
+with
+
+ perl ../../blah/foo.cmd arg1 arg2 arg3
+
+(note that the argument C<-my_opts> is taken care of by the C<extproc> line
+in your script, see L<C<extproc> on the first line>).
+
+To understand what the above I<magic> does, read perl docs about C<-S>
+switch - see L<perlrun>, and cmdref about C<extproc>:
+
+ view perl perlrun
+ man perlrun
+ view cmdref extproc
+ help extproc
+
+or whatever method you prefer.
+
+There are also endless possibilities to use I<executable extensions> of
+4os2, I<associations> of WPS and so on... However, if you use
+*nixish shell (like F<sh.exe> supplied in the binary distribution),
+you need to follow the syntax specified in L<perlrun/"Switches">.
+
+Note that B<-S> switch supports scripts with additional extensions
+F<.cmd>, F<.btm>, F<.bat>, F<.pl> as well.
+
+=head2 Starting OS/2 (and DOS) programs under Perl
+
+This is what system() (see L<perlfunc/system>), C<``> (see
+L<perlop/"I/O Operators">), and I<open pipe> (see L<perlfunc/open>)
+are for. (Avoid exec() (see L<perlfunc/exec>) unless you know what you
+do).
+
+Note however that to use some of these operators you need to have a
+sh-syntax shell installed (see L<"Pdksh">,
+L<"Frequently asked questions">), and perl should be able to find it
+(see L<"PERL_SH_DIR">).
+
+The cases when the shell is used are:
+
+=over
+
+=item 1
+
+One-argument system() (see L<perlfunc/system>), exec() (see L<perlfunc/exec>)
+with redirection or shell meta-characters;
+
+=item 2
+
+Pipe-open (see L<perlfunc/open>) with the command which contains redirection
+or shell meta-characters;
+
+=item 3
+
+Backticks C<``> (see L<perlop/"I/O Operators">) with the command which contains
+redirection or shell meta-characters;
+
+=item 4
+
+If the executable called by system()/exec()/pipe-open()/C<``> is a script
+with the "magic" C<#!> line or C<extproc> line which specifies shell;
+
+=item 5
+
+If the executable called by system()/exec()/pipe-open()/C<``> is a script
+without "magic" line, and C<$ENV{EXECSHELL}> is set to shell;
+
+=item 6
+
+If the executable called by system()/exec()/pipe-open()/C<``> is not
+found (is not this remark obsolete?);
+
+=item 7
+
+For globbing (see L<perlfunc/glob>, L<perlop/"I/O Operators">)
+(obsolete? Perl uses builtin globbing nowadays...).
+
+=back
+
+For the sake of speed for a common case, in the above algorithms
+backslashes in the command name are not considered as shell metacharacters.
+
+Perl starts scripts which begin with cookies
+C<extproc> or C<#!> directly, without an intervention of shell. Perl uses the
+same algorithm to find the executable as F<pdksh>: if the path
+on C<#!> line does not work, and contains C</>, then the directory
+part of the executable is ignored, and the executable
+is searched in F<.> and on C<PATH>. To find arguments for these scripts
+Perl uses a different algorithm than F<pdksh>: up to 3 arguments are
+recognized, and trailing whitespace is stripped.
+
+If a script
+does not contain such a cooky, then to avoid calling F<sh.exe>, Perl uses
+the same algorithm as F<pdksh>: if C<$ENV{EXECSHELL}> is set, the
+script is given as the first argument to this command, if not set, then
+C<$ENV{COMSPEC} /c> is used (or a hardwired guess if C<$ENV{COMSPEC}> is
+not set).
+
+When starting scripts directly, Perl uses exactly the same algorithm as for
+the search of script given by B<-S> command-line option: it will look in
+the current directory, then on components of C<$ENV{PATH}> using the
+following order of appended extensions: no extension, F<.cmd>, F<.btm>,
+F<.bat>, F<.pl>.
+
+Note that Perl will start to look for scripts only if OS/2 cannot start the
+specified application, thus C<system 'blah'> will not look for a script if
+there is an executable file F<blah.exe> I<anywhere> on C<PATH>. In
+other words, C<PATH> is essentially searched twice: once by the OS for
+an executable, then by Perl for scripts.
+
+Note also that executable files on OS/2 can have an arbitrary extension,
+but F<.exe> will be automatically appended if no dot is present in the name.
+The workaround is as simple as that: since F<blah.> and F<blah> denote the
+same file (at list on FAT and HPFS file systems), to start an executable residing in file F<n:/bin/blah> (no
+extension) give an argument C<n:/bin/blah.> (dot appended) to system().
+
+Perl will start PM programs from VIO (=text-mode) Perl process in a
+separate PM session;
+the opposite is not true: when you start a non-PM program from a PM
+Perl process, Perl would not run it in a separate session. If a separate
+session is desired, either ensure
+that shell will be used, as in C<system 'cmd /c myprog'>, or start it using
+optional arguments to system() documented in C<OS2::Process> module. This
+is considered to be a feature.
+
+=head1 Frequently asked questions
+
+=head2 "It does not work"
+
+Perl binary distributions come with a F<testperl.cmd> script which tries
+to detect common problems with misconfigured installations. There is a
+pretty large chance it will discover which step of the installation you
+managed to goof. C<;-)>
+
+=head2 I cannot run external programs
+
+=over 4
+
+=item *
+
+Did you run your programs with C<-w> switch? See
+L<Starting OS/2 (and DOS) programs under Perl>.
+
+=item *
+
+Do you try to run I<internal> shell commands, like C<`copy a b`>
+(internal for F<cmd.exe>), or C<`glob a*b`> (internal for ksh)? You
+need to specify your shell explicitly, like C<`cmd /c copy a b`>,
+since Perl cannot deduce which commands are internal to your shell.
+
+=back
+
+=head2 I cannot embed perl into my program, or use F<perl.dll> from my
+program.
+
+=over 4
+
+=item Is your program EMX-compiled with C<-Zmt -Zcrtdll>?
+
+Well, nowadays Perl DLL should be usable from a differently compiled
+program too... If you can run Perl code from REXX scripts (see
+L<OS2::REXX>), then there are some other aspect of interaction which
+are overlooked by the current hackish code to support
+differently-compiled principal programs.
+
+If everything else fails, you need to build a stand-alone DLL for
+perl. Contact me, I did it once. Sockets would not work, as a lot of
+other stuff.
+
+=item Did you use L<ExtUtils::Embed>?
+
+Some time ago I had reports it does not work. Nowadays it is checked
+in the Perl test suite, so grep F<./t> subdirectory of the build tree
+(as well as F<*.t> files in the F<./lib> subdirectory) to find how it
+should be done "correctly".
+
+=back
+
+=head2 C<``> and pipe-C<open> do not work under DOS.
+
+This may a variant of just L<"I cannot run external programs">, or a
+deeper problem. Basically: you I<need> RSX (see L<"Prerequisites">)
+for these commands to work, and you may need a port of F<sh.exe> which
+understands command arguments. One of such ports is listed in
+L<"Prerequisites"> under RSX. Do not forget to set variable
+C<L<"PERL_SH_DIR">> as well.
+
+DPMI is required for RSX.
+
+=head2 Cannot start C<find.exe "pattern" file>
+
+The whole idea of the "standard C API to start applications" is that
+the forms C<foo> and C<"foo"> of program arguments are completely
+interchangable. F<find> breaks this paradigm;
+
+ find "pattern" file
+ find pattern file
+
+are not equivalent; F<find> cannot be started directly using the above
+API. One needs a way to surround the doublequotes in some other
+quoting construction, necessarily having an extra non-Unixish shell in
+between.
+
+Use one of
+
+ system 'cmd', '/c', 'find "pattern" file';
+ `cmd /c 'find "pattern" file'`
+
+This would start F<find.exe> via F<cmd.exe> via C<sh.exe> via
+C<perl.exe>, but this is a price to pay if you want to use
+non-conforming program.
+
+=head1 INSTALLATION
+
+=head2 Automatic binary installation
+
+The most convenient way of installing a binary distribution of perl is via perl installer
+F<install.exe>. Just follow the instructions, and 99% of the
+installation blues would go away.
+
+Note however, that you need to have F<unzip.exe> on your path, and
+EMX environment I<running>. The latter means that if you just
+installed EMX, and made all the needed changes to F<Config.sys>,
+you may need to reboot in between. Check EMX runtime by running
+
+ emxrev
+
+Binary installer also creates a folder on your desktop with some useful
+objects. If you need to change some aspects of the work of the binary
+installer, feel free to edit the file F<Perl.pkg>. This may be useful
+e.g., if you need to run the installer many times and do not want to
+make many interactive changes in the GUI.
+
+B<Things not taken care of by automatic binary installation:>
+
+=over 15
+
+=item C<PERL_BADLANG>
+
+may be needed if you change your codepage I<after> perl installation,
+and the new value is not supported by EMX. See L<"PERL_BADLANG">.
+
+=item C<PERL_BADFREE>
+
+see L<"PERL_BADFREE">.
+
+=item F<Config.pm>
+
+This file resides somewhere deep in the location you installed your
+perl library, find it out by
+
+ perl -MConfig -le "print $INC{'Config.pm'}"
+
+While most important values in this file I<are> updated by the binary
+installer, some of them may need to be hand-edited. I know no such
+data, please keep me informed if you find one. Moreover, manual
+changes to the installed version may need to be accompanied by an edit
+of this file.
+
+=back
+
+B<NOTE>. Because of a typo the binary installer of 5.00305
+would install a variable C<PERL_SHPATH> into F<Config.sys>. Please
+remove this variable and put C<L<PERL_SH_DIR>> instead.
+
+=head2 Manual binary installation
+
+As of version 5.00305, OS/2 perl binary distribution comes split
+into 11 components. Unfortunately, to enable configurable binary
+installation, the file paths in the zip files are not absolute, but
+relative to some directory.
+
+Note that the extraction with the stored paths is still necessary
+(default with unzip, specify C<-d> to pkunzip). However, you
+need to know where to extract the files. You need also to manually
+change entries in F<Config.sys> to reflect where did you put the
+files. Note that if you have some primitive unzipper (like
+C<pkunzip>), you may get a lot of warnings/errors during
+unzipping. Upgrade to C<(w)unzip>.
+
+Below is the sample of what to do to reproduce the configuration on my
+machine. In F<VIEW.EXE> you can press C<Ctrl-Insert> now, and
+cut-and-paste from the resulting file - created in the directory you
+started F<VIEW.EXE> from.
+
+For each component, we mention environment variables related to each
+installation directory. Either choose directories to match your
+values of the variables, or create/append-to variables to take into
+account the directories.
+
+=over 3
+
+=item Perl VIO and PM executables (dynamically linked)
+
+ unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin
+ unzip perl_exc.zip *.dll -d f:/emx.add/dll
+
+(have the directories with C<*.exe> on PATH, and C<*.dll> on
+LIBPATH);
+
+=item Perl_ VIO executable (statically linked)
+
+ unzip perl_aou.zip -d f:/emx.add/bin
+
+(have the directory on PATH);
+
+=item Executables for Perl utilities
+
+ unzip perl_utl.zip -d f:/emx.add/bin
+
+(have the directory on PATH);
+
+=item Main Perl library
+
+ unzip perl_mlb.zip -d f:/perllib/lib
+
+If this directory is exactly the same as the prefix which was compiled
+into F<perl.exe>, you do not need to change
+anything. However, for perl to find the library if you use a different
+path, you need to
+C<set PERLLIB_PREFIX> in F<Config.sys>, see L<"PERLLIB_PREFIX">.
+
+=item Additional Perl modules
+
+ unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.12.3/
+
+Same remark as above applies. Additionally, if this directory is not
+one of directories on @INC (and @INC is influenced by C<PERLLIB_PREFIX>), you
+need to put this
+directory and subdirectory F<./os2> in C<PERLLIB> or C<PERL5LIB>
+variable. Do not use C<PERL5LIB> unless you have it set already. See
+L<perl/"ENVIRONMENT">.
+
+B<[Check whether this extraction directory is still applicable with
+the new directory structure layout!]>
+
+=item Tools to compile Perl modules
+
+ unzip perl_blb.zip -d f:/perllib/lib
+
+Same remark as for F<perl_ste.zip>.
+
+=item Manpages for Perl and utilities
+
+ unzip perl_man.zip -d f:/perllib/man
+
+This directory should better be on C<MANPATH>. You need to have a
+working F<man> to access these files.
+
+=item Manpages for Perl modules
+
+ unzip perl_mam.zip -d f:/perllib/man
+
+This directory should better be on C<MANPATH>. You need to have a
+working man to access these files.
+
+=item Source for Perl documentation
+
+ unzip perl_pod.zip -d f:/perllib/lib
+
+This is used by the C<perldoc> program (see L<perldoc>), and may be used to
+generate HTML documentation usable by WWW browsers, and
+documentation in zillions of other formats: C<info>, C<LaTeX>,
+C<Acrobat>, C<FrameMaker> and so on. [Use programs such as
+F<pod2latex> etc.]
+
+=item Perl manual in F<.INF> format
+
+ unzip perl_inf.zip -d d:/os2/book
+
+This directory should better be on C<BOOKSHELF>.
+
+=item Pdksh
+
+ unzip perl_sh.zip -d f:/bin
+
+This is used by perl to run external commands which explicitly
+require shell, like the commands using I<redirection> and I<shell
+metacharacters>. It is also used instead of explicit F</bin/sh>.
+
+Set C<PERL_SH_DIR> (see L<"PERL_SH_DIR">) if you move F<sh.exe> from
+the above location.
+
+B<Note.> It may be possible to use some other sh-compatible shell (untested).
+
+=back
+
+After you installed the components you needed and updated the
+F<Config.sys> correspondingly, you need to hand-edit
+F<Config.pm>. This file resides somewhere deep in the location you
+installed your perl library, find it out by
+
+ perl -MConfig -le "print $INC{'Config.pm'}"
+
+You need to correct all the entries which look like file paths (they
+currently start with C<f:/>).
+
+=head2 B<Warning>
+
+The automatic and manual perl installation leave precompiled paths
+inside perl executables. While these paths are overwriteable (see
+L<"PERLLIB_PREFIX">, L<"PERL_SH_DIR">), some people may prefer
+binary editing of paths inside the executables/DLLs.
+
+=head1 Accessing documentation
+
+Depending on how you built/installed perl you may have (otherwise
+identical) Perl documentation in the following formats:
+
+=head2 OS/2 F<.INF> file
+
+Most probably the most convenient form. Under OS/2 view it as
+
+ view perl
+ view perl perlfunc
+ view perl less
+ view perl ExtUtils::MakeMaker
+
+(currently the last two may hit a wrong location, but this may improve
+soon). Under Win* see L<"SYNOPSIS">.
+
+If you want to build the docs yourself, and have I<OS/2 toolkit>, run
+
+ pod2ipf > perl.ipf
+
+in F</perllib/lib/pod> directory, then
+
+ ipfc /inf perl.ipf
+
+(Expect a lot of errors during the both steps.) Now move it on your
+BOOKSHELF path.
+
+=head2 Plain text
+
+If you have perl documentation in the source form, perl utilities
+installed, and GNU groff installed, you may use
+
+ perldoc perlfunc
+ perldoc less
+ perldoc ExtUtils::MakeMaker
+
+to access the perl documentation in the text form (note that you may get
+better results using perl manpages).
+
+Alternately, try running pod2text on F<.pod> files.
+
+=head2 Manpages
+
+If you have F<man> installed on your system, and you installed perl
+manpages, use something like this:
+
+ man perlfunc
+ man 3 less
+ man ExtUtils.MakeMaker
+
+to access documentation for different components of Perl. Start with
+
+ man perl
+
+Note that dot (F<.>) is used as a package separator for documentation
+for packages, and as usual, sometimes you need to give the section - C<3>
+above - to avoid shadowing by the I<less(1) manpage>.
+
+Make sure that the directory B<above> the directory with manpages is
+on our C<MANPATH>, like this
+
+ set MANPATH=c:/man;f:/perllib/man
+
+for Perl manpages in C<f:/perllib/man/man1/> etc.
+
+=head2 HTML
+
+If you have some WWW browser available, installed the Perl
+documentation in the source form, and Perl utilities, you can build
+HTML docs. Cd to directory with F<.pod> files, and do like this
+
+ cd f:/perllib/lib/pod
+ pod2html
+
+After this you can direct your browser the file F<perl.html> in this
+directory, and go ahead with reading docs, like this:
+
+ explore file:///f:/perllib/lib/pod/perl.html
+
+Alternatively you may be able to get these docs prebuilt from CPAN.
+
+=head2 GNU C<info> files
+
+Users of Emacs would appreciate it very much, especially with
+C<CPerl> mode loaded. You need to get latest C<pod2texi> from C<CPAN>,
+or, alternately, the prebuilt info pages.
+
+=head2 F<PDF> files
+
+for C<Acrobat> are available on CPAN (may be for slightly older version of
+perl).
+
+=head2 C<LaTeX> docs
+
+can be constructed using C<pod2latex>.
+
+=head1 BUILD
+
+Here we discuss how to build Perl under OS/2.
+
+=head2 The short story
+
+Assume that you are a seasoned porter, so are sure that all the necessary
+tools are already present on your system, and you know how to get the Perl
+source distribution. Untar it, change to the extract directory, and
+
+ gnupatch -p0 < os2\diff.configure
+ sh Configure -des -D prefix=f:/perllib
+ make
+ make test
+ make install
+ make aout_test
+ make aout_install
+
+This puts the executables in f:/perllib/bin. Manually move them to the
+C<PATH>, manually move the built F<perl*.dll> to C<LIBPATH> (here for
+Perl DLL F<*> is a not-very-meaningful hex checksum), and run
+
+ make installcmd INSTALLCMDDIR=d:/ir/on/path
+
+Assuming that the C<man>-files were put on an appropriate location,
+this completes the installation of minimal Perl system. (The binary
+distribution contains also a lot of additional modules, and the
+documentation in INF format.)
+
+What follows is a detailed guide through these steps.
+
+=head2 Prerequisites
+
+You need to have the latest EMX development environment, the full
+GNU tool suite (gawk renamed to awk, and GNU F<find.exe>
+earlier on path than the OS/2 F<find.exe>, same with F<sort.exe>, to
+check use
+
+ find --version
+ sort --version
+
+). You need the latest version of F<pdksh> installed as F<sh.exe>.
+
+Check that you have B<BSD> libraries and headers installed, and -
+optionally - Berkeley DB headers and libraries, and crypt.
+
+Possible locations to get the files:
+
+
+ ftp://ftp.uni-heidelberg.de/pub/os2/unix/
+ http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2
+ http://cd.textfiles.com/hobbesos29804/disk1/DEV32/
+ http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
+
+It is reported that the following archives contain enough utils to
+build perl: F<gnufutil.zip>, F<gnusutil.zip>, F<gnututil.zip>, F<gnused.zip>,
+F<gnupatch.zip>, F<gnuawk.zip>, F<gnumake.zip>, F<gnugrep.zip>, F<bsddev.zip> and
+F<ksh527rt.zip> (or a later version). Note that all these utilities are
+known to be available from LEO:
+
+ ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/
+
+Note also that the F<db.lib> and F<db.a> from the EMX distribution
+are not suitable for multi-threaded compile (even single-threaded
+flavor of Perl uses multi-threaded C RTL, for
+compatibility with XFree86-OS/2). Get a corrected one from
+
+ http://www.ilyaz.org/software/os2/db_mt.zip
+
+If you have I<exactly the same version of Perl> installed already,
+make sure that no copies or perl are currently running. Later steps
+of the build may fail since an older version of F<perl.dll> loaded into
+memory may be found. Running C<make test> becomes meaningless, since
+the test are checking a previous build of perl (this situation is detected
+and reported by F<lib/os2_base.t> test). Do not forget to unset
+C<PERL_EMXLOAD_SEC> in environment.
+
+Also make sure that you have F</tmp> directory on the current drive,
+and F<.> directory in your C<LIBPATH>. One may try to correct the
+latter condition by
+
+ set BEGINLIBPATH .\.
+
+if you use something like F<CMD.EXE> or latest versions of
+F<4os2.exe>. (Setting BEGINLIBPATH to just C<.> is ignored by the
+OS/2 kernel.)
+
+Make sure your gcc is good for C<-Zomf> linking: run C<omflibs>
+script in F</emx/lib> directory.
+
+Check that you have link386 installed. It comes standard with OS/2,
+but may be not installed due to customization. If typing
+
+ link386
+
+shows you do not have it, do I<Selective install>, and choose C<Link
+object modules> in I<Optional system utilities/More>. If you get into
+link386 prompts, press C<Ctrl-C> to exit.
+
+=head2 Getting perl source
+
+You need to fetch the latest perl source (including developers
+releases). With some probability it is located in
+
+ http://www.cpan.org/src/
+ http://www.cpan.org/src/unsupported
+
+If not, you may need to dig in the indices to find it in the directory
+of the current maintainer.
+
+Quick cycle of developers release may break the OS/2 build time to
+time, looking into
+
+ http://www.cpan.org/ports/os2/
+
+may indicate the latest release which was publicly released by the
+maintainer. Note that the release may include some additional patches
+to apply to the current source of perl.
+
+Extract it like this
+
+ tar vzxf perl5.00409.tar.gz
+
+You may see a message about errors while extracting F<Configure>. This is
+because there is a conflict with a similarly-named file F<configure>.
+
+Change to the directory of extraction.
+
+=head2 Application of the patches
+
+You need to apply the patches in F<./os2/diff.*> like this:
+
+ gnupatch -p0 < os2\diff.configure
+
+You may also need to apply the patches supplied with the binary
+distribution of perl. It also makes sense to look on the
+perl5-porters mailing list for the latest OS/2-related patches (see
+L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>). Such
+patches usually contain strings C</os2/> and C<patch>, so it makes
+sense looking for these strings.
+
+=head2 Hand-editing
+
+You may look into the file F<./hints/os2.sh> and correct anything
+wrong you find there. I do not expect it is needed anywhere.
+
+=head2 Making
+
+ sh Configure -des -D prefix=f:/perllib
+
+C<prefix> means: where to install the resulting perl library. Giving
+correct prefix you may avoid the need to specify C<PERLLIB_PREFIX>,
+see L<"PERLLIB_PREFIX">.
+
+I<Ignore the message about missing C<ln>, and about C<-c> option to
+tr>. The latter is most probably already fixed, if you see it and can trace
+where the latter spurious warning comes from, please inform me.
+
+Now
+
+ make
+
+At some moment the built may die, reporting a I<version mismatch> or
+I<unable to run F<perl>>. This means that you do not have F<.> in
+your LIBPATH, so F<perl.exe> cannot find the needed F<perl67B2.dll> (treat
+these hex digits as line noise). After this is fixed the build
+should finish without a lot of fuss.
+
+=head2 Testing
+
+Now run
+
+ make test
+
+All tests should succeed (with some of them skipped). If you have the
+same version of Perl installed, it is crucial that you have C<.> early
+in your LIBPATH (or in BEGINLIBPATH), otherwise your tests will most
+probably test the wrong version of Perl.
+
+Some tests may generate extra messages similar to
+
+=over 4
+
+=item A lot of C<bad free>
+
+in database tests related to Berkeley DB. I<This should be fixed already.>
+If it persists, you may disable this warnings, see L<"PERL_BADFREE">.
+
+=item Process terminated by SIGTERM/SIGINT
+
+This is a standard message issued by OS/2 applications. *nix
+applications die in silence. It is considered to be a feature. One can
+easily disable this by appropriate sighandlers.
+
+However the test engine bleeds these message to screen in unexpected
+moments. Two messages of this kind I<should> be present during
+testing.
+
+=back
+
+To get finer test reports, call
+
+ perl t/harness
+
+The report with F<io/pipe.t> failing may look like this:
+
+ Failed Test Status Wstat Total Fail Failed List of failed
+ ------------------------------------------------------------
+ io/pipe.t 12 1 8.33% 9
+ 7 tests skipped, plus 56 subtests skipped.
+ Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 99.98% okay.
+
+The reasons for most important skipped tests are:
+
+=over 8
+
+=item F<op/fs.t>
+
+=over 4
+
+=item 18
+
+Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS
+provides only 2sec time granularity (for compatibility with FAT?).
+
+=item 25
+
+Checks C<truncate()> on a filehandle just opened for write - I do not
+know why this should or should not work.
+
+=back
+
+=item F<op/stat.t>
+
+Checks C<stat()>. Tests:
+
+=over 4
+
+=item 4
+
+Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS
+provides only 2sec time granularity (for compatibility with FAT?).
+
+=back
+
+=back
+
+=head2 Installing the built perl
+
+If you haven't yet moved C<perl*.dll> onto LIBPATH, do it now.
+
+Run
+
+ make install
+
+It would put the generated files into needed locations. Manually put
+F<perl.exe>, F<perl__.exe> and F<perl___.exe> to a location on your
+PATH, F<perl.dll> to a location on your LIBPATH.
+
+Run
+
+ make installcmd INSTALLCMDDIR=d:/ir/on/path
+
+to convert perl utilities to F<.cmd> files and put them on
+PATH. You need to put F<.EXE>-utilities on path manually. They are
+installed in C<$prefix/bin>, here C<$prefix> is what you gave to
+F<Configure>, see L<Making>.
+
+If you use C<man>, either move the installed F<*/man/> directories to
+your C<MANPATH>, or modify C<MANPATH> to match the location. (One
+could have avoided this by providing a correct C<manpath> option to
+F<./Configure>, or editing F<./config.sh> between configuring and
+making steps.)
+
+=head2 C<a.out>-style build
+
+Proceed as above, but make F<perl_.exe> (see L<"perl_.exe">) by
+
+ make perl_
+
+test and install by
+
+ make aout_test
+ make aout_install
+
+Manually put F<perl_.exe> to a location on your PATH.
+
+B<Note.> The build process for C<perl_> I<does not know> about all the
+dependencies, so you should make sure that anything is up-to-date,
+say, by doing
+
+ make perl_dll
+
+first.
+
+=head1 Building a binary distribution
+
+[This section provides a short overview only...]
+
+Building should proceed differently depending on whether the version of perl
+you install is already present and used on your system, or is a new version
+not yet used. The description below assumes that the version is new, so
+installing its DLLs and F<.pm> files will not disrupt the operation of your
+system even if some intermediate steps are not yet fully working.
+
+The other cases require a little bit more convoluted procedures. Below I
+suppose that the current version of Perl is C<5.8.2>, so the executables are
+named accordingly.
+
+=over
+
+=item 1.
+
+Fully build and test the Perl distribution. Make sure that no tests are
+failing with C<test> and C<aout_test> targets; fix the bugs in Perl and
+the Perl test suite detected by these tests. Make sure that C<all_test>
+make target runs as clean as possible. Check that C<os2/perlrexx.cmd>
+runs fine.
+
+=item 2.
+
+Fully install Perl, including C<installcmd> target. Copy the generated DLLs
+to C<LIBPATH>; copy the numbered Perl executables (as in F<perl5.8.2.exe>)
+to C<PATH>; copy C<perl_.exe> to C<PATH> as C<perl_5.8.2.exe>. Think whether
+you need backward-compatibility DLLs. In most cases you do not need to install
+them yet; but sometime this may simplify the following steps.
+
+=item 3.
+
+Make sure that C<CPAN.pm> can download files from CPAN. If not, you may need
+to manually install C<Net::FTP>.
+
+=item 4.
+
+Install the bundle C<Bundle::OS2_default>
+
+ perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_1
+
+This may take a couple of hours on 1GHz processor (when run the first time).
+And this should not be necessarily a smooth procedure. Some modules may not
+specify required dependencies, so one may need to repeat this procedure several
+times until the results stabilize.
+
+ perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_2
+ perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_3
+
+Even after they stabilize, some tests may fail.
+
+Fix as many discovered bugs as possible. Document all the bugs which are not
+fixed, and all the failures with unknown reasons. Inspect the produced logs
+F<00cpan_i_1> to find suspiciously skipped tests, and other fishy events.
+
+Keep in mind that I<installation> of some modules may fail too: for example,
+the DLLs to update may be already loaded by F<CPAN.pm>. Inspect the C<install>
+logs (in the example above F<00cpan_i_1> etc) for errors, and install things
+manually, as in
+
+ cd $CPANHOME/.cpan/build/Digest-MD5-2.31
+ make install
+
+Some distributions may fail some tests, but you may want to install them
+anyway (as above, or via C<force install> command of C<CPAN.pm> shell-mode).
+
+Since this procedure may take quite a long time to complete, it makes sense
+to "freeze" your CPAN configuration by disabling periodic updates of the
+local copy of CPAN index: set C<index_expire> to some big value (I use 365),
+then save the settings
+
+ CPAN> o conf index_expire 365
+ CPAN> o conf commit
+
+Reset back to the default value C<1> when you are finished.
+
+=item 5.
+
+When satisfied with the results, rerun the C<installcmd> target. Now you
+can copy C<perl5.8.2.exe> to C<perl.exe>, and install the other OMF-build
+executables: C<perl__.exe> etc. They are ready to be used.
+
+=item 6.
+
+Change to the C<./pod> directory of the build tree, download the Perl logo
+F<CamelGrayBig.BMP>, and run
+
+ ( perl2ipf > perl.ipf ) |& tee 00ipf
+ ipfc /INF perl.ipf |& tee 00inf
+
+This produces the Perl docs online book C<perl.INF>. Install in on
+C<BOOKSHELF> path.
+
+=item 7.
+
+Now is the time to build statically linked executable F<perl_.exe> which
+includes newly-installed via C<Bundle::OS2_default> modules. Doing testing
+via C<CPAN.pm> is going to be painfully slow, since it statically links
+a new executable per XS extension.
+
+Here is a possible workaround: create a toplevel F<Makefile.PL> in
+F<$CPANHOME/.cpan/build/> with contents being (compare with L<Making
+executables with a custom collection of statically loaded extensions>)
+
+ use ExtUtils::MakeMaker;
+ WriteMakefile NAME => 'dummy';
+
+execute this as
+
+ perl_5.8.2.exe Makefile.PL <nul |& tee 00aout_c1
+ make -k all test <nul |& 00aout_t1
+
+Again, this procedure should not be absolutely smooth. Some C<Makefile.PL>'s
+in subdirectories may be buggy, and would not run as "child" scripts. The
+interdependency of modules can strike you; however, since non-XS modules
+are already installed, the prerequisites of most modules have a very good
+chance to be present.
+
+If you discover some glitches, move directories of problematic modules to a
+different location; if these modules are non-XS modules, you may just ignore
+them - they are already installed; the remaining, XS, modules you need to
+install manually one by one.
+
+After each such removal you need to rerun the C<Makefile.PL>/C<make> process;
+usually this procedure converges soon. (But be sure to convert all the
+necessary external C libraries from F<.lib> format to F<.a> format: run one of
+
+ emxaout foo.lib
+ emximp -o foo.a foo.lib
+
+whichever is appropriate.) Also, make sure that the DLLs for external
+libraries are usable with with executables compiled without C<-Zmtd> options.
+
+When you are sure that only a few subdirectories
+lead to failures, you may want to add C<-j4> option to C<make> to speed up
+skipping subdirectories with already finished build.
+
+When you are satisfied with the results of tests, install the build C libraries
+for extensions:
+
+ make install |& tee 00aout_i
+
+Now you can rename the file F<./perl.exe> generated during the last phase
+to F<perl_5.8.2.exe>; place it on C<PATH>; if there is an inter-dependency
+between some XS modules, you may need to repeat the C<test>/C<install> loop
+with this new executable and some excluded modules - until the procedure
+converges.
+
+Now you have all the necessary F<.a> libraries for these Perl modules in the
+places where Perl builder can find it. Use the perl builder: change to an
+empty directory, create a "dummy" F<Makefile.PL> again, and run
+
+ perl_5.8.2.exe Makefile.PL |& tee 00c
+ make perl |& tee 00p
+
+This should create an executable F<./perl.exe> with all the statically loaded
+extensions built in. Compare the generated F<perlmain.c> files to make sure
+that during the iterations the number of loaded extensions only increases.
+Rename F<./perl.exe> to F<perl_5.8.2.exe> on C<PATH>.
+
+When it converges, you got a functional variant of F<perl_5.8.2.exe>; copy it
+to C<perl_.exe>. You are done with generation of the local Perl installation.
+
+=item 8.
+
+Make sure that the installed modules are actually installed in the location
+of the new Perl, and are not inherited from entries of @INC given for
+inheritance from the older versions of Perl: set C<PERLLIB_582_PREFIX> to
+redirect the new version of Perl to a new location, and copy the installed
+files to this new location. Redo the tests to make sure that the versions of
+modules inherited from older versions of Perl are not needed.
+
+Actually, the log output of L<pod2ipf> during the step 6 gives a very detailed
+info about which modules are loaded from which place; so you may use it as
+an additional verification tool.
+
+Check that some temporary files did not make into the perl install tree.
+Run something like this
+
+ pfind . -f "!(/\.(pm|pl|ix|al|h|a|lib|txt|pod|imp|bs|dll|ld|bs|inc|xbm|yml|cgi|uu|e2x|skip|packlist|eg|cfg|html|pub|enc|all|ini|po|pot)$/i or /^\w+$/") | less
+
+in the install tree (both top one and F<sitelib> one).
+
+Compress all the DLLs with F<lxlite>. The tiny F<.exe> can be compressed with
+C</c:max> (the bug only appears when there is a fixup in the last 6 bytes of a
+page (?); since the tiny executables are much smaller than a page, the bug
+will not hit). Do not compress C<perl_.exe> - it would not work under DOS.
+
+=item 9.
+
+Now you can generate the binary distribution. This is done by running the
+test of the CPAN distribution C<OS2::SoftInstaller>. Tune up the file
+F<test.pl> to suit the layout of current version of Perl first. Do not
+forget to pack the necessary external DLLs accordingly. Include the
+description of the bugs and test suite failures you could not fix. Include
+the small-stack versions of Perl executables from Perl build directory.
+
+Include F<perl5.def> so that people can relink the perl DLL preserving
+the binary compatibility, or can create compatibility DLLs. Include the diff
+files (C<diff -pu old new>) of fixes you did so that people can rebuild your
+version. Include F<perl5.map> so that one can use remote debugging.
+
+=item 10.
+
+Share what you did with the other people. Relax. Enjoy fruits of your work.
+
+=item 11.
+
+Brace yourself for thanks, bug reports, hate mail and spam coming as result
+of the previous step. No good deed should remain unpunished!
+
+=back
+
+=head1 Building custom F<.EXE> files
+
+The Perl executables can be easily rebuilt at any moment. Moreover, one can
+use the I<embedding> interface (see L<perlembed>) to make very customized
+executables.
+
+=head2 Making executables with a custom collection of statically loaded extensions
+
+It is a little bit easier to do so while I<decreasing> the list of statically
+loaded extensions. We discuss this case only here.
+
+=over
+
+=item 1.
+
+Change to an empty directory, and create a placeholder <Makefile.PL>:
+
+ use ExtUtils::MakeMaker;
+ WriteMakefile NAME => 'dummy';
+
+=item 2.
+
+Run it with the flavor of Perl (F<perl.exe> or F<perl_.exe>) you want to
+rebuild.
+
+ perl_ Makefile.PL
+
+=item 3.
+
+Ask it to create new Perl executable:
+
+ make perl
+
+(you may need to manually add C<PERLTYPE=-DPERL_CORE> to this commandline on
+some versions of Perl; the symptom is that the command-line globbing does not
+work from OS/2 shells with the newly-compiled executable; check with
+
+ .\perl.exe -wle "print for @ARGV" *
+
+).
+
+=item 4.
+
+The previous step created F<perlmain.c> which contains a list of newXS() calls
+near the end. Removing unnecessary calls, and rerunning
+
+ make perl
+
+will produce a customized executable.
+
+=back
+
+=head2 Making executables with a custom search-paths
+
+The default perl executable is flexible enough to support most usages.
+However, one may want something yet more flexible; for example, one may want
+to find Perl DLL relatively to the location of the EXE file; or one may want
+to ignore the environment when setting the Perl-library search patch, etc.
+
+If you fill comfortable with I<embedding> interface (see L<perlembed>), such
+things are easy to do repeating the steps outlined in L<Making
+executables with a custom collection of statically loaded extensions>, and
+doing more comprehensive edits to main() of F<perlmain.c>. The people with
+little desire to understand Perl can just rename main(), and do necessary
+modification in a custom main() which calls the renamed function in appropriate
+time.
+
+However, there is a third way: perl DLL exports the main() function and several
+callbacks to customize the search path. Below is a complete example of a
+"Perl loader" which
+
+=over
+
+=item 1.
+
+Looks for Perl DLL in the directory C<$exedir/../dll>;
+
+=item 2.
+
+Prepends the above directory to C<BEGINLIBPATH>;
+
+=item 3.
+
+Fails if the Perl DLL found via C<BEGINLIBPATH> is different from what was
+loaded on step 1; e.g., another process could have loaded it from C<LIBPATH>
+or from a different value of C<BEGINLIBPATH>. In these cases one needs to
+modify the setting of the system so that this other process either does not
+run, or loads the DLL from C<BEGINLIBPATH> with C<LIBPATHSTRICT=T> (available
+with kernels after September 2000).
+
+=item 4.
+
+Loads Perl library from C<$exedir/../dll/lib/>.
+
+=item 5.
+
+Uses Bourne shell from C<$exedir/../dll/sh/ksh.exe>.
+
+=back
+
+For best results compile the C file below with the same options as the Perl
+DLL. However, a lot of functionality will work even if the executable is not
+an EMX applications, e.g., if compiled with
+
+ gcc -Wall -DDOSISH -DOS2=1 -O2 -s -Zomf -Zsys perl-starter.c -DPERL_DLL_BASENAME=\"perl312F\" -Zstack 8192 -Zlinker /PM:VIO
+
+Here is the sample C file:
+
+ #define INCL_DOS
+ #define INCL_NOPM
+ /* These are needed for compile if os2.h includes os2tk.h, not os2emx.h */
+ #define INCL_DOSPROCESS
+ #include <os2.h>
+
+ #include "EXTERN.h"
+ #define PERL_IN_MINIPERLMAIN_C
+ #include "perl.h"
+
+ static char *me;
+ HMODULE handle;
+
+ static void
+ die_with(char *msg1, char *msg2, char *msg3, char *msg4)
+ {
+ ULONG c;
+ char *s = " error: ";
+
+ DosWrite(2, me, strlen(me), &c);
+ DosWrite(2, s, strlen(s), &c);
+ DosWrite(2, msg1, strlen(msg1), &c);
+ DosWrite(2, msg2, strlen(msg2), &c);
+ DosWrite(2, msg3, strlen(msg3), &c);
+ DosWrite(2, msg4, strlen(msg4), &c);
+ DosWrite(2, "\r\n", 2, &c);
+ exit(255);
+ }
+
+ typedef ULONG (*fill_extLibpath_t)(int type, char *pre, char *post, int replace, char *msg);
+ typedef int (*main_t)(int type, char *argv[], char *env[]);
+ typedef int (*handler_t)(void* data, int which);
+
+ #ifndef PERL_DLL_BASENAME
+ # define PERL_DLL_BASENAME "perl"
+ #endif
+
+ static HMODULE
+ load_perl_dll(char *basename)
+ {
+ char buf[300], fail[260];
+ STRLEN l, dirl;
+ fill_extLibpath_t f;
+ ULONG rc_fullname;
+ HMODULE handle, handle1;
+
+ if (_execname(buf, sizeof(buf) - 13) != 0)
+ die_with("Can't find full path: ", strerror(errno), "", "");
+ /* XXXX Fill `me' with new value */
+ l = strlen(buf);
+ while (l && buf[l-1] != '/' && buf[l-1] != '\\')
+ l--;
+ dirl = l - 1;
+ strcpy(buf + l, basename);
+ l += strlen(basename);
+ strcpy(buf + l, ".dll");
+ if ( (rc_fullname = DosLoadModule(fail, sizeof fail, buf, &handle)) != 0
+ && DosLoadModule(fail, sizeof fail, basename, &handle) != 0 )
+ die_with("Can't load DLL ", buf, "", "");
+ if (rc_fullname)
+ return handle; /* was loaded with short name; all is fine */
+ if (DosQueryProcAddr(handle, 0, "fill_extLibpath", (PFN*)&f))
+ die_with(buf, ": DLL exports no symbol ", "fill_extLibpath", "");
+ buf[dirl] = 0;
+ if (f(0 /*BEGINLIBPATH*/, buf /* prepend */, NULL /* append */,
+ 0 /* keep old value */, me))
+ die_with(me, ": prepending BEGINLIBPATH", "", "");
+ if (DosLoadModule(fail, sizeof fail, basename, &handle1) != 0)
+ die_with(me, ": finding perl DLL again via BEGINLIBPATH", "", "");
+ buf[dirl] = '\\';
+ if (handle1 != handle) {
+ if (DosQueryModuleName(handle1, sizeof(fail), fail))
+ strcpy(fail, "???");
+ die_with(buf, ":\n\tperl DLL via BEGINLIBPATH is different: \n\t",
+ fail,
+ "\n\tYou may need to manipulate global BEGINLIBPATH and LIBPATHSTRICT"
+ "\n\tso that the other copy is loaded via BEGINLIBPATH.");
+ }
+ return handle;
+ }
+
+ int
+ main(int argc, char **argv, char **env)
+ {
+ main_t f;
+ handler_t h;
+
+ me = argv[0];
+ /**/
+ handle = load_perl_dll(PERL_DLL_BASENAME);
+
+ if (DosQueryProcAddr(handle, 0, "Perl_OS2_handler_install", (PFN*)&h))
+ die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "Perl_OS2_handler_install", "");
+ if ( !h((void *)"~installprefix", Perlos2_handler_perllib_from)
+ || !h((void *)"~dll", Perlos2_handler_perllib_to)
+ || !h((void *)"~dll/sh/ksh.exe", Perlos2_handler_perl_sh) )
+ die_with(PERL_DLL_BASENAME, ": Can't install @INC manglers", "", "");
+
+ if (DosQueryProcAddr(handle, 0, "dll_perlmain", (PFN*)&f))
+ die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "dll_perlmain", "");
+ return f(argc, argv, env);
+ }
+
+
+=head1 Build FAQ
+
+=head2 Some C</> became C<\> in pdksh.
+
+You have a very old pdksh. See L<Prerequisites>.
+
+=head2 C<'errno'> - unresolved external
+
+You do not have MT-safe F<db.lib>. See L<Prerequisites>.
+
+=head2 Problems with tr or sed
+
+reported with very old version of tr and sed.
+
+=head2 Some problem (forget which ;-)
+
+You have an older version of F<perl.dll> on your LIBPATH, which
+broke the build of extensions.
+
+=head2 Library ... not found
+
+You did not run C<omflibs>. See L<Prerequisites>.
+
+=head2 Segfault in make
+
+You use an old version of GNU make. See L<Prerequisites>.
+
+=head2 op/sprintf test failure
+
+This can result from a bug in emx sprintf which was fixed in 0.9d fix 03.
+
+=head1 Specific (mis)features of OS/2 port
+
+=head2 C<setpriority>, C<getpriority>
+
+Note that these functions are compatible with *nix, not with the older
+ports of '94 - 95. The priorities are absolute, go from 32 to -95,
+lower is quicker. 0 is the default priority.
+
+B<WARNING>. Calling C<getpriority> on a non-existing process could lock
+the system before Warp3 fixpak22. Starting with Warp3, Perl will use
+a workaround: it aborts getpriority() if the process is not present.
+This is not possible on older versions C<2.*>, and has a race
+condition anyway.
+
+=head2 C<system()>
+
+Multi-argument form of C<system()> allows an additional numeric
+argument. The meaning of this argument is described in
+L<OS2::Process>.
+
+When finding a program to run, Perl first asks the OS to look for executables
+on C<PATH> (OS/2 adds extension F<.exe> if no extension is present).
+If not found, it looks for a script with possible extensions
+added in this order: no extension, F<.cmd>, F<.btm>,
+F<.bat>, F<.pl>. If found, Perl checks the start of the file for magic
+strings C<"#!"> and C<"extproc ">. If found, Perl uses the rest of the
+first line as the beginning of the command line to run this script. The
+only mangling done to the first line is extraction of arguments (currently
+up to 3), and ignoring of the path-part of the "interpreter" name if it can't
+be found using the full path.
+
+E.g., C<system 'foo', 'bar', 'baz'> may lead Perl to finding
+F<C:/emx/bin/foo.cmd> with the first line being
+
+ extproc /bin/bash -x -c
+
+If F</bin/bash.exe> is not found, then Perl looks for an executable F<bash.exe> on
+C<PATH>. If found in F<C:/emx.add/bin/bash.exe>, then the above system() is
+translated to
+
+ system qw(C:/emx.add/bin/bash.exe -x -c C:/emx/bin/foo.cmd bar baz)
+
+One additional translation is performed: instead of F</bin/sh> Perl uses
+the hardwired-or-customized shell (see C<L<"PERL_SH_DIR">>).
+
+The above search for "interpreter" is recursive: if F<bash> executable is not
+found, but F<bash.btm> is found, Perl will investigate its first line etc.
+The only hardwired limit on the recursion depth is implicit: there is a limit
+4 on the number of additional arguments inserted before the actual arguments
+given to system(). In particular, if no additional arguments are specified
+on the "magic" first lines, then the limit on the depth is 4.
+
+If Perl finds that the found executable is of PM type when the
+current session is not, it will start the new process in a separate session of
+necessary type. Call via C<OS2::Process> to disable this magic.
+
+B<WARNING>. Due to the described logic, you need to explicitly
+specify F<.com> extension if needed. Moreover, if the executable
+F<perl5.6.1> is requested, Perl will not look for F<perl5.6.1.exe>.
+[This may change in the future.]
+
+=head2 C<extproc> on the first line
+
+If the first chars of a Perl script are C<"extproc ">, this line is treated
+as C<#!>-line, thus all the switches on this line are processed (twice
+if script was started via cmd.exe). See L<perlrun/DESCRIPTION>.
+
+=head2 Additional modules:
+
+L<OS2::Process>, L<OS2::DLL>, L<OS2::REXX>, L<OS2::PrfDB>, L<OS2::ExtAttr>. These
+modules provide access to additional numeric argument for C<system>
+and to the information about the running process,
+to DLLs having functions with REXX signature and to the REXX runtime, to
+OS/2 databases in the F<.INI> format, and to Extended Attributes.
+
+Two additional extensions by Andreas Kaiser, C<OS2::UPM>, and
+C<OS2::FTP>, are included into C<ILYAZ> directory, mirrored on CPAN.
+Other OS/2-related extensions are available too.
+
+=head2 Prebuilt methods:
+
+=over 4
+
+=item C<File::Copy::syscopy>
+
+used by C<File::Copy::copy>, see L<File::Copy>.
+
+=item C<DynaLoader::mod2fname>
+
+used by C<DynaLoader> for DLL name mangling.
+
+=item C<Cwd::current_drive()>
+
+Self explanatory.
+
+=item C<Cwd::sys_chdir(name)>
+
+leaves drive as it is.
+
+=item C<Cwd::change_drive(name)>
+
+chanes the "current" drive.
+
+=item C<Cwd::sys_is_absolute(name)>
+
+means has drive letter and is_rooted.
+
+=item C<Cwd::sys_is_rooted(name)>
+
+means has leading C<[/\\]> (maybe after a drive-letter:).
+
+=item C<Cwd::sys_is_relative(name)>
+
+means changes with current dir.
+
+=item C<Cwd::sys_cwd(name)>
+
+Interface to cwd from EMX. Used by C<Cwd::cwd>.
+
+=item C<Cwd::sys_abspath(name, dir)>
+
+Really really odious function to implement. Returns absolute name of
+file which would have C<name> if CWD were C<dir>. C<Dir> defaults to the
+current dir.
+
+=item C<Cwd::extLibpath([type])>
+
+Get current value of extended library search path. If C<type> is
+present and positive, works with C<END_LIBPATH>, if negative, works
+with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>.
+
+=item C<Cwd::extLibpath_set( path [, type ] )>
+
+Set current value of extended library search path. If C<type> is
+present and positive, works with <END_LIBPATH>, if negative, works
+with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>.
+
+=item C<OS2::Error(do_harderror,do_exception)>
+
+Returns C<undef> if it was not called yet, otherwise bit 1 is
+set if on the previous call do_harderror was enabled, bit
+2 is set if on previous call do_exception was enabled.
+
+This function enables/disables error popups associated with
+hardware errors (Disk not ready etc.) and software exceptions.
+
+I know of no way to find out the state of popups I<before> the first call
+to this function.
+
+=item C<OS2::Errors2Drive(drive)>
+
+Returns C<undef> if it was not called yet, otherwise return false if errors
+were not requested to be written to a hard drive, or the drive letter if
+this was requested.
+
+This function may redirect error popups associated with hardware errors
+(Disk not ready etc.) and software exceptions to the file POPUPLOG.OS2 at
+the root directory of the specified drive. Overrides OS2::Error() specified
+by individual programs. Given argument undef will disable redirection.
+
+Has global effect, persists after the application exits.
+
+I know of no way to find out the state of redirection of popups to the disk
+I<before> the first call to this function.
+
+=item OS2::SysInfo()
+
+Returns a hash with system information. The keys of the hash are
+
+ MAX_PATH_LENGTH, MAX_TEXT_SESSIONS, MAX_PM_SESSIONS,
+ MAX_VDM_SESSIONS, BOOT_DRIVE, DYN_PRI_VARIATION,
+ MAX_WAIT, MIN_SLICE, MAX_SLICE, PAGE_SIZE,
+ VERSION_MAJOR, VERSION_MINOR, VERSION_REVISION,
+ MS_COUNT, TIME_LOW, TIME_HIGH, TOTPHYSMEM, TOTRESMEM,
+ TOTAVAILMEM, MAXPRMEM, MAXSHMEM, TIMER_INTERVAL,
+ MAX_COMP_LENGTH, FOREGROUND_FS_SESSION,
+ FOREGROUND_PROCESS
+
+=item OS2::BootDrive()
+
+Returns a letter without colon.
+
+=item C<OS2::MorphPM(serve)>, C<OS2::UnMorphPM(serve)>
+
+Transforms the current application into a PM application and back.
+The argument true means that a real message loop is going to be served.
+OS2::MorphPM() returns the PM message queue handle as an integer.
+
+See L<"Centralized management of resources"> for additional details.
+
+=item C<OS2::Serve_Messages(force)>
+
+Fake on-demand retrieval of outstanding PM messages. If C<force> is false,
+will not dispatch messages if a real message loop is known to
+be present. Returns number of messages retrieved.
+
+Dies with "QUITing..." if WM_QUIT message is obtained.
+
+=item C<OS2::Process_Messages(force [, cnt])>
+
+Retrieval of PM messages until window creation/destruction.
+If C<force> is false, will not dispatch messages if a real message loop
+is known to be present.
+
+Returns change in number of windows. If C<cnt> is given,
+it is incremented by the number of messages retrieved.
+
+Dies with "QUITing..." if WM_QUIT message is obtained.
+
+=item C<OS2::_control87(new,mask)>
+
+the same as L<_control87(3)> of EMX. Takes integers as arguments, returns
+the previous coprocessor control word as an integer. Only bits in C<new> which
+are present in C<mask> are changed in the control word.
+
+=item OS2::get_control87()
+
+gets the coprocessor control word as an integer.
+
+=item C<OS2::set_control87_em(new=MCW_EM,mask=MCW_EM)>
+
+The variant of OS2::_control87() with default values good for
+handling exception mask: if no C<mask>, uses exception mask part of C<new>
+only. If no C<new>, disables all the floating point exceptions.
+
+See L<"Misfeatures"> for details.
+
+=item C<OS2::DLLname([how [, \&xsub]])>
+
+Gives the information about the Perl DLL or the DLL containing the C
+function bound to by C<&xsub>. The meaning of C<how> is: default (2):
+full name; 0: handle; 1: module name.
+
+=back
+
+(Note that some of these may be moved to different libraries -
+eventually).
+
+
+=head2 Prebuilt variables:
+
+=over 4
+
+=item $OS2::emx_rev
+
+numeric value is the same as _emx_rev of EMX, a string value the same
+as _emx_vprt (similar to C<0.9c>).
+
+=item $OS2::emx_env
+
+same as _emx_env of EMX, a number similar to 0x8001.
+
+=item $OS2::os_ver
+
+a number C<OS_MAJOR + 0.001 * OS_MINOR>.
+
+=item $OS2::is_aout
+
+true if the Perl library was compiled in AOUT format.
+
+=item $OS2::can_fork
+
+true if the current executable is an AOUT EMX executable, so Perl can
+fork. Do not use this, use the portable check for
+$Config::Config{dfork}.
+
+=item $OS2::nsyserror
+
+This variable (default is 1) controls whether to enforce the contents
+of $^E to start with C<SYS0003>-like id. If set to 0, then the string
+value of $^E is what is available from the OS/2 message file. (Some
+messages in this file have an C<SYS0003>-like id prepended, some not.)
+
+=back
+
+=head2 Misfeatures
+
+=over 4
+
+=item *
+
+Since L<flock(3)> is present in EMX, but is not functional, it is
+emulated by perl. To disable the emulations, set environment variable
+C<USE_PERL_FLOCK=0>.
+
+=item *
+
+Here is the list of things which may be "broken" on
+EMX (from EMX docs):
+
+=over 4
+
+=item *
+
+The functions L<recvmsg(3)>, L<sendmsg(3)>, and L<socketpair(3)> are not
+implemented.
+
+=item *
+
+L<sock_init(3)> is not required and not implemented.
+
+=item *
+
+L<flock(3)> is not yet implemented (dummy function). (Perl has a workaround.)
+
+=item *
+
+L<kill(3)>: Special treatment of PID=0, PID=1 and PID=-1 is not implemented.
+
+=item *
+
+L<waitpid(3)>:
+
+ WUNTRACED
+ Not implemented.
+ waitpid() is not implemented for negative values of PID.
+
+=back
+
+Note that C<kill -9> does not work with the current version of EMX.
+
+=item *
+
+See L<"Text-mode filehandles">.
+
+=item *
+
+Unix-domain sockets on OS/2 live in a pseudo-file-system C</sockets/...>.
+To avoid a failure to create a socket with a name of a different form,
+C<"/socket/"> is prepended to the socket name (unless it starts with this
+already).
+
+This may lead to problems later in case the socket is accessed via the
+"usual" file-system calls using the "initial" name.
+
+=item *
+
+Apparently, IBM used a compiler (for some period of time around '95?) which
+changes FP mask right and left. This is not I<that> bad for IBM's
+programs, but the same compiler was used for DLLs which are used with
+general-purpose applications. When these DLLs are used, the state of
+floating-point flags in the application is not predictable.
+
+What is much worse, some DLLs change the floating point flags when in
+_DLLInitTerm() (e.g., F<TCP32IP>). This means that even if you do not I<call>
+any function in the DLL, just the act of loading this DLL will reset your
+flags. What is worse, the same compiler was used to compile some HOOK DLLs.
+Given that HOOK dlls are executed in the context of I<all> the applications
+in the system, this means a complete unpredictablity of floating point
+flags on systems using such HOOK DLLs. E.g., F<GAMESRVR.DLL> of B<DIVE>
+origin changes the floating point flags on each write to the TTY of a VIO
+(windowed text-mode) applications.
+
+Some other (not completely debugged) situations when FP flags change include
+some video drivers (?), and some operations related to creation of the windows.
+People who code B<OpenGL> may have more experience on this.
+
+Perl is generally used in the situation when all the floating-point
+exceptions are ignored, as is the default under EMX. If they are not ignored,
+some benign Perl programs would get a C<SIGFPE> and would die a horrible death.
+
+To circumvent this, Perl uses two hacks. They help against I<one> type of
+damage only: FP flags changed when loading a DLL.
+
+One of the hacks is to disable floating point exceptions on Perl startup (as
+is the default with EMX). This helps only with compile-time-linked DLLs
+changing the flags before main() had a chance to be called.
+
+The other hack is to restore FP flags after a call to dlopen(). This helps
+against similar damage done by DLLs _DLLInitTerm() at runtime. Currently
+no way to switch these hacks off is provided.
+
+=back
+
+=head2 Modifications
+
+Perl modifies some standard C library calls in the following ways:
+
+=over 9
+
+=item C<popen>
+
+C<my_popen> uses F<sh.exe> if shell is required, cf. L<"PERL_SH_DIR">.
+
+=item C<tmpnam>
+
+is created using C<TMP> or C<TEMP> environment variable, via
+C<tempnam>.
+
+=item C<tmpfile>
+
+If the current directory is not writable, file is created using modified
+C<tmpnam>, so there may be a race condition.
+
+=item C<ctermid>
+
+a dummy implementation.
+
+=item C<stat>
+
+C<os2_stat> special-cases F</dev/tty> and F</dev/con>.
+
+=item C<mkdir>, C<rmdir>
+
+these EMX functions do not work if the path contains a trailing C</>.
+Perl contains a workaround for this.
+
+=item C<flock>
+
+Since L<flock(3)> is present in EMX, but is not functional, it is
+emulated by perl. To disable the emulations, set environment variable
+C<USE_PERL_FLOCK=0>.
+
+=back
+
+=head2 Identifying DLLs
+
+All the DLLs built with the current versions of Perl have ID strings
+identifying the name of the extension, its version, and the version
+of Perl required for this DLL. Run C<bldlevel DLL-name> to find this
+info.
+
+=head2 Centralized management of resources
+
+Since to call certain OS/2 API one needs to have a correctly initialized
+C<Win> subsystem, OS/2-specific extensions may require getting C<HAB>s and
+C<HMQ>s. If an extension would do it on its own, another extension could
+fail to initialize.
+
+Perl provides a centralized management of these resources:
+
+=over
+
+=item C<HAB>
+
+To get the HAB, the extension should call C<hab = perl_hab_GET()> in C. After
+this call is performed, C<hab> may be accessed as C<Perl_hab>. There is
+no need to release the HAB after it is used.
+
+If by some reasons F<perl.h> cannot be included, use
+
+ extern int Perl_hab_GET(void);
+
+instead.
+
+=item C<HMQ>
+
+There are two cases:
+
+=over
+
+=item *
+
+the extension needs an C<HMQ> only because some API will not work otherwise.
+Use C<serve = 0> below.
+
+=item *
+
+the extension needs an C<HMQ> since it wants to engage in a PM event loop.
+Use C<serve = 1> below.
+
+=back
+
+To get an C<HMQ>, the extension should call C<hmq = perl_hmq_GET(serve)> in C.
+After this call is performed, C<hmq> may be accessed as C<Perl_hmq>.
+
+To signal to Perl that HMQ is not needed any more, call
+C<perl_hmq_UNSET(serve)>. Perl process will automatically morph/unmorph itself
+into/from a PM process if HMQ is needed/not-needed. Perl will automatically
+enable/disable C<WM_QUIT> message during shutdown if the message queue is
+served/not-served.
+
+B<NOTE>. If during a shutdown there is a message queue which did not disable
+WM_QUIT, and which did not process the received WM_QUIT message, the
+shutdown will be automatically cancelled. Do not call C<perl_hmq_GET(1)>
+unless you are going to process messages on an orderly basis.
+
+=item * Treating errors reported by OS/2 API
+
+There are two principal conventions (it is useful to call them C<Dos*>
+and C<Win*> - though this part of the function signature is not always
+determined by the name of the API) of reporting the error conditions
+of OS/2 API. Most of C<Dos*> APIs report the error code as the result
+of the call (so 0 means success, and there are many types of errors).
+Most of C<Win*> API report success/fail via the result being
+C<TRUE>/C<FALSE>; to find the reason for the failure one should call
+WinGetLastError() API.
+
+Some C<Win*> entry points also overload a "meaningful" return value
+with the error indicator; having a 0 return value indicates an error.
+Yet some other C<Win*> entry points overload things even more, and 0
+return value may mean a successful call returning a valid value 0, as
+well as an error condition; in the case of a 0 return value one should
+call WinGetLastError() API to distinguish a successful call from a
+failing one.
+
+By convention, all the calls to OS/2 API should indicate their
+failures by resetting $^E. All the Perl-accessible functions which
+call OS/2 API may be broken into two classes: some die()s when an API
+error is encountered, the other report the error via a false return
+value (of course, this does not concern Perl-accessible functions
+which I<expect> a failure of the OS/2 API call, having some workarounds
+coded).
+
+Obviously, in the situation of the last type of the signature of an OS/2
+API, it is must more convenient for the users if the failure is
+indicated by die()ing: one does not need to check $^E to know that
+something went wrong. If, however, this solution is not desirable by
+some reason, the code in question should reset $^E to 0 before making
+this OS/2 API call, so that the caller of this Perl-accessible
+function has a chance to distinguish a success-but-0-return value from
+a failure. (One may return undef as an alternative way of reporting
+an error.)
+
+The macros to simplify this type of error propagation are
+
+=over
+
+=item C<CheckOSError(expr)>
+
+Returns true on error, sets $^E. Expects expr() be a call of
+C<Dos*>-style API.
+
+=item C<CheckWinError(expr)>
+
+Returns true on error, sets $^E. Expects expr() be a call of
+C<Win*>-style API.
+
+=item C<SaveWinError(expr)>
+
+Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false.
+
+=item C<SaveCroakWinError(expr,die,name1,name2)>
+
+Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false,
+and die()s if C<die> and $^E are true. The message to die is the
+concatenated strings C<name1> and C<name2>, separated by C<": "> from
+the contents of $^E.
+
+=item C<WinError_2_Perl_rc>
+
+Sets C<Perl_rc> to the return value of WinGetLastError().
+
+=item C<FillWinError>
+
+Sets C<Perl_rc> to the return value of WinGetLastError(), and sets $^E
+to the corresponding value.
+
+=item C<FillOSError(rc)>
+
+Sets C<Perl_rc> to C<rc>, and sets $^E to the corresponding value.
+
+=back
+
+=item * Loading DLLs and ordinals in DLLs
+
+Some DLLs are only present in some versions of OS/2, or in some
+configurations of OS/2. Some exported entry points are present only
+in DLLs shipped with some versions of OS/2. If these DLLs and entry
+points were linked directly for a Perl executable/DLL or from a Perl
+extensions, this binary would work only with the specified
+versions/setups. Even if these entry points were not needed, the
+I<load> of the executable (or DLL) would fail.
+
+For example, many newer useful APIs are not present in OS/2 v2; many
+PM-related APIs require DLLs not available on floppy-boot setup.
+
+To make these calls fail I<only when the calls are executed>, one
+should call these API via a dynamic linking API. There is a subsystem
+in Perl to simplify such type of calls. A large number of entry
+points available for such linking is provided (see C<entries_ordinals>
+- and also C<PMWIN_entries> - in F<os2ish.h>). These ordinals can be
+accessed via the APIs:
+
+ CallORD(), DeclFuncByORD(), DeclVoidFuncByORD(),
+ DeclOSFuncByORD(), DeclWinFuncByORD(), AssignFuncPByORD(),
+ DeclWinFuncByORD_CACHE(), DeclWinFuncByORD_CACHE_survive(),
+ DeclWinFuncByORD_CACHE_resetError_survive(),
+ DeclWinFunc_CACHE(), DeclWinFunc_CACHE_resetError(),
+ DeclWinFunc_CACHE_survive(), DeclWinFunc_CACHE_resetError_survive()
+
+See the header files and the C code in the supplied OS/2-related
+modules for the details on usage of these functions.
+
+Some of these functions also combine dynaloading semantic with the
+error-propagation semantic discussed above.
+
+=back
+
+=head1 Perl flavors
+
+Because of idiosyncrasies of OS/2 one cannot have all the eggs in the
+same basket (though EMX environment tries hard to overcome this
+limitations, so the situation may somehow improve). There are 4
+executables for Perl provided by the distribution:
+
+=head2 F<perl.exe>
+
+The main workhorse. This is a chimera executable: it is compiled as an
+C<a.out>-style executable, but is linked with C<omf>-style dynamic
+library F<perl.dll>, and with dynamic CRT DLL. This executable is a
+VIO application.
+
+It can load perl dynamic extensions, and it can fork().
+
+B<Note.> Keep in mind that fork() is needed to open a pipe to yourself.
+
+=head2 F<perl_.exe>
+
+This is a statically linked C<a.out>-style executable. It cannot
+load dynamic Perl extensions. The executable supplied in binary
+distributions has a lot of extensions prebuilt, thus the above restriction is
+important only if you use custom-built extensions. This executable is a VIO
+application.
+
+I<This is the only executable with does not require OS/2.> The
+friends locked into C<M$> world would appreciate the fact that this
+executable runs under DOS, Win0.3*, Win0.95 and WinNT with an
+appropriate extender. See L<"Other OSes">.
+
+=head2 F<perl__.exe>
+
+This is the same executable as F<perl___.exe>, but it is a PM
+application.
+
+B<Note.> Usually (unless explicitly redirected during the startup)
+STDIN, STDERR, and STDOUT of a PM
+application are redirected to F<nul>. However, it is possible to I<see>
+them if you start C<perl__.exe> from a PM program which emulates a
+console window, like I<Shell mode> of Emacs or EPM. Thus it I<is
+possible> to use Perl debugger (see L<perldebug>) to debug your PM
+application (but beware of the message loop lockups - this will not
+work if you have a message queue to serve, unless you hook the serving
+into the getc() function of the debugger).
+
+Another way to see the output of a PM program is to run it as
+
+ pm_prog args 2>&1 | cat -
+
+with a shell I<different> from F<cmd.exe>, so that it does not create
+a link between a VIO session and the session of C<pm_porg>. (Such a link
+closes the VIO window.) E.g., this works with F<sh.exe> - or with Perl!
+
+ open P, 'pm_prog args 2>&1 |' or die;
+ print while <P>;
+
+The flavor F<perl__.exe> is required if you want to start your program without
+a VIO window present, but not C<detach>ed (run C<help detach> for more info).
+Very useful for extensions which use PM, like C<Perl/Tk> or C<OpenGL>.
+
+Note also that the differences between PM and VIO executables are only
+in the I<default> behaviour. One can start I<any> executable in
+I<any> kind of session by using the arguments C</fs>, C</pm> or
+C</win> switches of the command C<start> (of F<CMD.EXE> or a similar
+shell). Alternatively, one can use the numeric first argument of the
+C<system> Perl function (see L<OS2::Process>).
+
+=head2 F<perl___.exe>
+
+This is an C<omf>-style executable which is dynamically linked to
+F<perl.dll> and CRT DLL. I know no advantages of this executable
+over C<perl.exe>, but it cannot fork() at all. Well, one advantage is
+that the build process is not so convoluted as with C<perl.exe>.
+
+It is a VIO application.
+
+=head2 Why strange names?
+
+Since Perl processes the C<#!>-line (cf.
+L<perlrun/DESCRIPTION>, L<perlrun/Switches>,
+L<perldiag/"Not a perl script">,
+L<perldiag/"No Perl script found in input">), it should know when a
+program I<is a Perl>. There is some naming convention which allows
+Perl to distinguish correct lines from wrong ones. The above names are
+almost the only names allowed by this convention which do not contain
+digits (which have absolutely different semantics).
+
+=head2 Why dynamic linking?
+
+Well, having several executables dynamically linked to the same huge
+library has its advantages, but this would not substantiate the
+additional work to make it compile. The reason is the complicated-to-developers
+but very quick and convenient-to-users "hard" dynamic linking used by OS/2.
+
+There are two distinctive features of the dyna-linking model of OS/2:
+first, all the references to external functions are resolved at the compile time;
+second, there is no runtime fixup of the DLLs after they are loaded into memory.
+The first feature is an enormous advantage over other models: it avoids
+conflicts when several DLLs used by an application export entries with
+the same name. In such cases "other" models of dyna-linking just choose
+between these two entry points using some random criterion - with predictable
+disasters as results. But it is the second feature which requires the build
+of F<perl.dll>.
+
+The address tables of DLLs are patched only once, when they are
+loaded. The addresses of the entry points into DLLs are guaranteed to be
+the same for all the programs which use the same DLL. This removes the
+runtime fixup - once DLL is loaded, its code is read-only.
+
+While this allows some (significant?) performance advantages, this makes life
+much harder for developers, since the above scheme makes it impossible
+for a DLL to be "linked" to a symbol in the F<.EXE> file. Indeed, this
+would need a DLL to have different relocations tables for the
+(different) executables which use this DLL.
+
+However, a dynamically loaded Perl extension is forced to use some symbols
+from the perl
+executable, e.g., to know how to find the arguments to the functions:
+the arguments live on the perl
+internal evaluation stack. The solution is to put the main code of
+the interpreter into a DLL, and make the F<.EXE> file which just loads
+this DLL into memory and supplies command-arguments. The extension DLL
+cannot link to symbols in F<.EXE>, but it has no problem linking
+to symbols in the F<.DLL>.
+
+This I<greatly> increases the load time for the application (as well as
+complexity of the compilation). Since interpreter is in a DLL,
+the C RTL is basically forced to reside in a DLL as well (otherwise
+extensions would not be able to use CRT). There are some advantages if
+you use different flavors of perl, such as running F<perl.exe> and
+F<perl__.exe> simultaneously: they share the memory of F<perl.dll>.
+
+B<NOTE>. There is one additional effect which makes DLLs more wasteful:
+DLLs are loaded in the shared memory region, which is a scarse resource
+given the 512M barrier of the "standard" OS/2 virtual memory. The code of
+F<.EXE> files is also shared by all the processes which use the particular
+F<.EXE>, but they are "shared in the private address space of the process";
+this is possible because the address at which different sections
+of the F<.EXE> file are loaded is decided at compile-time, thus all the
+processes have these sections loaded at same addresses, and no fixup
+of internal links inside the F<.EXE> is needed.
+
+Since DLLs may be loaded at run time, to have the same mechanism for DLLs
+one needs to have the address range of I<any of the loaded> DLLs in the
+system to be available I<in all the processes> which did not load a particular
+DLL yet. This is why the DLLs are mapped to the shared memory region.
+
+=head2 Why chimera build?
+
+Current EMX environment does not allow DLLs compiled using Unixish
+C<a.out> format to export symbols for data (or at least some types of
+data). This forces C<omf>-style compile of F<perl.dll>.
+
+Current EMX environment does not allow F<.EXE> files compiled in
+C<omf> format to fork(). fork() is needed for exactly three Perl
+operations:
+
+=over 4
+
+=item *
+
+explicit fork() in the script,
+
+=item *
+
+C<open FH, "|-">
+
+=item *
+
+C<open FH, "-|">, in other words, opening pipes to itself.
+
+=back
+
+While these operations are not questions of life and death, they are
+needed for a lot of
+useful scripts. This forces C<a.out>-style compile of
+F<perl.exe>.
+
+
+=head1 ENVIRONMENT
+
+Here we list environment variables with are either OS/2- and DOS- and
+Win*-specific, or are more important under OS/2 than under other OSes.
+
+=head2 C<PERLLIB_PREFIX>
+
+Specific for EMX port. Should have the form
+
+ path1;path2
+
+or
+
+ path1 path2
+
+If the beginning of some prebuilt path matches F<path1>, it is
+substituted with F<path2>.
+
+Should be used if the perl library is moved from the default
+location in preference to C<PERL(5)LIB>, since this would not leave wrong
+entries in @INC. For example, if the compiled version of perl looks for @INC
+in F<f:/perllib/lib>, and you want to install the library in
+F<h:/opt/gnu>, do
+
+ set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu
+
+This will cause Perl with the prebuilt @INC of
+
+ f:/perllib/lib/5.00553/os2
+ f:/perllib/lib/5.00553
+ f:/perllib/lib/site_perl/5.00553/os2
+ f:/perllib/lib/site_perl/5.00553
+ .
+
+to use the following @INC:
+
+ h:/opt/gnu/5.00553/os2
+ h:/opt/gnu/5.00553
+ h:/opt/gnu/site_perl/5.00553/os2
+ h:/opt/gnu/site_perl/5.00553
+ .
+
+=head2 C<PERL_BADLANG>
+
+If 0, perl ignores setlocale() failing. May be useful with some
+strange I<locale>s.
+
+=head2 C<PERL_BADFREE>
+
+If 0, perl would not warn of in case of unwarranted free(). With older
+perls this might be
+useful in conjunction with the module DB_File, which was buggy when
+dynamically linked and OMF-built.
+
+Should not be set with newer Perls, since this may hide some I<real> problems.
+
+=head2 C<PERL_SH_DIR>
+
+Specific for EMX port. Gives the directory part of the location for
+F<sh.exe>.
+
+=head2 C<USE_PERL_FLOCK>
+
+Specific for EMX port. Since L<flock(3)> is present in EMX, but is not
+functional, it is emulated by perl. To disable the emulations, set
+environment variable C<USE_PERL_FLOCK=0>.
+
+=head2 C<TMP> or C<TEMP>
+
+Specific for EMX port. Used as storage place for temporary files.
+
+=head1 Evolution
+
+Here we list major changes which could make you by surprise.
+
+=head2 Text-mode filehandles
+
+Starting from version 5.8, Perl uses a builtin translation layer for
+text-mode files. This replaces the efficient well-tested EMX layer by
+some code which should be best characterized as a "quick hack".
+
+In addition to possible bugs and an inability to follow changes to the
+translation policy with off/on switches of TERMIO translation, this
+introduces a serious incompatible change: before sysread() on
+text-mode filehandles would go through the translation layer, now it
+would not.
+
+=head2 Priorities
+
+C<setpriority> and C<getpriority> are not compatible with earlier
+ports by Andreas Kaiser. See C<"setpriority, getpriority">.
+
+=head2 DLL name mangling: pre 5.6.2
+
+With the release 5.003_01 the dynamically loadable libraries
+should be rebuilt when a different version of Perl is compiled. In particular,
+DLLs (including F<perl.dll>) are now created with the names
+which contain a checksum, thus allowing workaround for OS/2 scheme of
+caching DLLs.
+
+It may be possible to code a simple workaround which would
+
+=over
+
+=item *
+
+find the old DLLs looking through the old @INC;
+
+=item *
+
+mangle the names according to the scheme of new perl and copy the DLLs to
+these names;
+
+=item *
+
+edit the internal C<LX> tables of DLL to reflect the change of the name
+(probably not needed for Perl extension DLLs, since the internally coded names
+are not used for "specific" DLLs, they used only for "global" DLLs).
+
+=item *
+
+edit the internal C<IMPORT> tables and change the name of the "old"
+F<perl????.dll> to the "new" F<perl????.dll>.
+
+=back
+
+=head2 DLL name mangling: 5.6.2 and beyond
+
+In fact mangling of I<extension> DLLs was done due to misunderstanding
+of the OS/2 dynaloading model. OS/2 (effectively) maintains two
+different tables of loaded DLL:
+
+=over
+
+=item Global DLLs
+
+those loaded by the base name from C<LIBPATH>; including those
+associated at link time;
+
+=item specific DLLs
+
+loaded by the full name.
+
+=back
+
+When resolving a request for a global DLL, the table of already-loaded
+specific DLLs is (effectively) ignored; moreover, specific DLLs are
+I<always> loaded from the prescribed path.
+
+There is/was a minor twist which makes this scheme fragile: what to do
+with DLLs loaded from
+
+=over
+
+=item C<BEGINLIBPATH> and C<ENDLIBPATH>
+
+(which depend on the process)
+
+=item F<.> from C<LIBPATH>
+
+which I<effectively> depends on the process (although C<LIBPATH> is the
+same for all the processes).
+
+=back
+
+Unless C<LIBPATHSTRICT> is set to C<T> (and the kernel is after
+2000/09/01), such DLLs are considered to be global. When loading a
+global DLL it is first looked in the table of already-loaded global
+DLLs. Because of this the fact that one executable loaded a DLL from
+C<BEGINLIBPATH> and C<ENDLIBPATH>, or F<.> from C<LIBPATH> may affect
+I<which> DLL is loaded when I<another> executable requests a DLL with
+the same name. I<This> is the reason for version-specific mangling of
+the DLL name for perl DLL.
+
+Since the Perl extension DLLs are always loaded with the full path,
+there is no need to mangle their names in a version-specific ways:
+their directory already reflects the corresponding version of perl,
+and @INC takes into account binary compatibility with older version.
+Starting from C<5.6.2> the name mangling scheme is fixed to be the
+same as for Perl 5.005_53 (same as in a popular binary release). Thus
+new Perls will be able to I<resolve the names> of old extension DLLs
+if @INC allows finding their directories.
+
+However, this still does not guarantee that these DLL may be loaded.
+The reason is the mangling of the name of the I<Perl DLL>. And since
+the extension DLLs link with the Perl DLL, extension DLLs for older
+versions would load an older Perl DLL, and would most probably
+segfault (since the data in this DLL is not properly initialized).
+
+There is a partial workaround (which can be made complete with newer
+OS/2 kernels): create a forwarder DLL with the same name as the DLL of
+the older version of Perl, which forwards the entry points to the
+newer Perl's DLL. Make this DLL accessible on (say) the C<BEGINLIBPATH> of
+the new Perl executable. When the new executable accesses old Perl's
+extension DLLs, they would request the old Perl's DLL by name, get the
+forwarder instead, so effectively will link with the currently running
+(new) Perl DLL.
+
+This may break in two ways:
+
+=over
+
+=item *
+
+Old perl executable is started when a new executable is running has
+loaded an extension compiled for the old executable (ouph!). In this
+case the old executable will get a forwarder DLL instead of the old
+perl DLL, so would link with the new perl DLL. While not directly
+fatal, it will behave the same as new executable. This beats the whole
+purpose of explicitly starting an old executable.
+
+=item *
+
+A new executable loads an extension compiled for the old executable
+when an old perl executable is running. In this case the extension
+will not pick up the forwarder - with fatal results.
+
+=back
+
+With support for C<LIBPATHSTRICT> this may be circumvented - unless
+one of DLLs is started from F<.> from C<LIBPATH> (I do not know
+whether C<LIBPATHSTRICT> affects this case).
+
+B<REMARK>. Unless newer kernels allow F<.> in C<BEGINLIBPATH> (older
+do not), this mess cannot be completely cleaned. (It turns out that
+as of the beginning of 2002, F<.> is not allowed, but F<.\.> is - and
+it has the same effect.)
+
+
+B<REMARK>. C<LIBPATHSTRICT>, C<BEGINLIBPATH> and C<ENDLIBPATH> are
+not environment variables, although F<cmd.exe> emulates them on C<SET
+...> lines. From Perl they may be accessed by L<Cwd::extLibpath> and
+L<Cwd::extLibpath_set>.
+
+=head2 DLL forwarder generation
+
+Assume that the old DLL is named F<perlE0AC.dll> (as is one for
+5.005_53), and the new version is 5.6.1. Create a file
+F<perl5shim.def-leader> with
+
+ LIBRARY 'perlE0AC' INITINSTANCE TERMINSTANCE
+ DESCRIPTION '@#perl5-porters@perl.org:5.006001#@ Perl module for 5.00553 -> Perl 5.6.1 forwarder'
+ CODE LOADONCALL
+ DATA LOADONCALL NONSHARED MULTIPLE
+ EXPORTS
+
+modifying the versions/names as needed. Run
+
+ perl -wnle "next if 0../EXPORTS/; print qq( \"$1\") if /\"(\w+)\"/" perl5.def >lst
+
+in the Perl build directory (to make the DLL smaller replace perl5.def
+with the definition file for the older version of Perl if present).
+
+ cat perl5shim.def-leader lst >perl5shim.def
+ gcc -Zomf -Zdll -o perlE0AC.dll perl5shim.def -s -llibperl
+
+(ignore multiple C<warning L4085>).
+
+=head2 Threading
+
+As of release 5.003_01 perl is linked to multithreaded C RTL
+DLL. If perl itself is not compiled multithread-enabled, so will not be perl's
+malloc(). However, extensions may use multiple thread on their own
+risk.
+
+This was needed to compile C<Perl/Tk> for XFree86-OS/2 out-of-the-box, and
+link with DLLs for other useful libraries, which typically are compiled
+with C<-Zmt -Zcrtdll>.
+
+=head2 Calls to external programs
+
+Due to a popular demand the perl external program calling has been
+changed wrt Andreas Kaiser's port. I<If> perl needs to call an
+external program I<via shell>, the F<f:/bin/sh.exe> will be called, or
+whatever is the override, see L<"PERL_SH_DIR">.
+
+Thus means that you need to get some copy of a F<sh.exe> as well (I
+use one from pdksh). The path F<F:/bin> above is set up automatically during
+the build to a correct value on the builder machine, but is
+overridable at runtime,
+
+B<Reasons:> a consensus on C<perl5-porters> was that perl should use
+one non-overridable shell per platform. The obvious choices for OS/2
+are F<cmd.exe> and F<sh.exe>. Having perl build itself would be impossible
+with F<cmd.exe> as a shell, thus I picked up C<sh.exe>. This assures almost
+100% compatibility with the scripts coming from *nix. As an added benefit
+this works as well under DOS if you use DOS-enabled port of pdksh
+(see L<"Prerequisites">).
+
+B<Disadvantages:> currently F<sh.exe> of pdksh calls external programs
+via fork()/exec(), and there is I<no> functioning exec() on
+OS/2. exec() is emulated by EMX by an asynchronous call while the caller
+waits for child completion (to pretend that the C<pid> did not change). This
+means that 1 I<extra> copy of F<sh.exe> is made active via fork()/exec(),
+which may lead to some resources taken from the system (even if we do
+not count extra work needed for fork()ing).
+
+Note that this a lesser issue now when we do not spawn F<sh.exe>
+unless needed (metachars found).
+
+One can always start F<cmd.exe> explicitly via
+
+ system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ...
+
+If you need to use F<cmd.exe>, and do not want to hand-edit thousands of your
+scripts, the long-term solution proposed on p5-p is to have a directive
+
+ use OS2::Cmd;
+
+which will override system(), exec(), C<``>, and
+C<open(,'...|')>. With current perl you may override only system(),
+readpipe() - the explicit version of C<``>, and maybe exec(). The code
+will substitute the one-argument call to system() by
+C<CORE::system('cmd.exe', '/c', shift)>.
+
+If you have some working code for C<OS2::Cmd>, please send it to me,
+I will include it into distribution. I have no need for such a module, so
+cannot test it.
+
+For the details of the current situation with calling external programs,
+see L<Starting OS/2 (and DOS) programs under Perl>. Set us mention a couple
+of features:
+
+=over 4
+
+=item *
+
+External scripts may be called by their basename. Perl will try the same
+extensions as when processing B<-S> command-line switch.
+
+=item *
+
+External scripts starting with C<#!> or C<extproc > will be executed directly,
+without calling the shell, by calling the program specified on the rest of
+the first line.
+
+=back
+
+=head2 Memory allocation
+
+Perl uses its own malloc() under OS/2 - interpreters are usually malloc-bound
+for speed, but perl is not, since its malloc is lightning-fast.
+Perl-memory-usage-tuned benchmarks show that Perl's malloc is 5 times quicker
+than EMX one. I do not have convincing data about memory footprint, but
+a (pretty random) benchmark showed that Perl's one is 5% better.
+
+Combination of perl's malloc() and rigid DLL name resolution creates
+a special problem with library functions which expect their return value to
+be free()d by system's free(). To facilitate extensions which need to call
+such functions, system memory-allocation functions are still available with
+the prefix C<emx_> added. (Currently only DLL perl has this, it should
+propagate to F<perl_.exe> shortly.)
+
+=head2 Threads
+
+One can build perl with thread support enabled by providing C<-D usethreads>
+option to F<Configure>. Currently OS/2 support of threads is very
+preliminary.
+
+Most notable problems:
+
+=over 4
+
+=item C<COND_WAIT>
+
+may have a race condition (but probably does not due to edge-triggered
+nature of OS/2 Event semaphores). (Needs a reimplementation (in terms of chaining
+waiting threads, with the linked list stored in per-thread structure?)?)
+
+=item F<os2.c>
+
+has a couple of static variables used in OS/2-specific functions. (Need to be
+moved to per-thread structure, or serialized?)
+
+=back
+
+Note that these problems should not discourage experimenting, since they
+have a low probability of affecting small programs.
+
+=head1 BUGS
+
+This description is not updated often (since 5.6.1?), see F<./os2/Changes>
+(L<perlos2delta>) for more info.
+
+=cut
+
+OS/2 extensions
+~~~~~~~~~~~~~~~
+I include 3 extensions by Andreas Kaiser, OS2::REXX, OS2::UPM, and OS2::FTP,
+into my ftp directory, mirrored on CPAN. I made
+some minor changes needed to compile them by standard tools. I cannot
+test UPM and FTP, so I will appreciate your feedback. Other extensions
+there are OS2::ExtAttr, OS2::PrfDB for tied access to EAs and .INI
+files - and maybe some other extensions at the time you read it.
+
+Note that OS2 perl defines 2 pseudo-extension functions
+OS2::Copy::copy and DynaLoader::mod2fname (many more now, see
+L<Prebuilt methods>).
+
+The -R switch of older perl is deprecated. If you need to call a REXX code
+which needs access to variables, include the call into a REXX compartment
+created by
+ REXX_call {...block...};
+
+Two new functions are supported by REXX code,
+ REXX_eval 'string';
+ REXX_eval_with 'string', REXX_function_name => \&perl_sub_reference;
+
+If you have some other extensions you want to share, send the code to
+me. At least two are available: tied access to EA's, and tied access
+to system databases.
+
+=head1 AUTHOR
+
+Ilya Zakharevich, cpan@ilyaz.org
+
+=head1 SEE ALSO
+
+perl(1).
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlos390.pod b/Master/tlpkg/tlperl/lib/pods/perlos390.pod
new file mode 100644
index 00000000000..4229e2b317e
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlos390.pod
@@ -0,0 +1,444 @@
+This document is written in pod format hence there are punctuation
+characters in odd places. Do not worry, you've apparently got the
+ASCII->EBCDIC translation worked out correctly. You can read more
+about pod in pod/perlpod.pod or the short summary in the INSTALL file.
+
+=head1 NAME
+
+README.os390 - building and installing Perl for OS/390 and z/OS
+
+=head1 SYNOPSIS
+
+This document will help you Configure, build, test and install Perl
+on OS/390 (aka z/OS) Unix System Services.
+
+=head1 DESCRIPTION
+
+This is a fully ported Perl for OS/390 Version 2 Release 3, 5, 6, 7,
+8, and 9. It may work on other versions or releases, but those are
+the ones we've tested it on.
+
+You may need to carry out some system configuration tasks before
+running the Configure script for Perl.
+
+
+=head2 Tools
+
+The z/OS Unix Tools and Toys list may prove helpful and contains links
+to ports of much of the software helpful for building Perl.
+http://www.ibm.com/servers/eserver/zseries/zos/unix/bpxa1toy.html
+
+
+=head2 Unpacking Perl distribution on OS/390
+
+If using ftp remember to transfer the distribution in binary format.
+
+Gunzip/gzip for OS/390 is discussed at:
+
+ http://www.ibm.com/servers/eserver/zseries/zos/unix/bpxa1ty1.html
+
+to extract an ASCII tar archive on OS/390, try this:
+
+ pax -o to=IBM-1047,from=ISO8859-1 -r < latest.tar
+
+or
+
+ zcat latest.tar.Z | pax -o to=IBM-1047,from=ISO8859-1 -r
+
+If you get lots of errors of the form
+
+ tar: FSUM7171 ...: cannot set uid/gid: EDC5139I Operation not permitted.
+
+you didn't read the above and tried to use tar instead of pax, you'll
+first have to remove the (now corrupt) perl directory
+
+ rm -rf perl-...
+
+and then use pax.
+
+=head2 Setup and utilities for Perl on OS/390
+
+Be sure that your yacc installation is in place including any necessary
+parser template files. If you have not already done so then be sure to:
+
+ cp /samples/yyparse.c /etc
+
+This may also be a good time to ensure that your /etc/protocol file
+and either your /etc/resolv.conf or /etc/hosts files are in place.
+The IBM document that described such USS system setup issues was
+SC28-1890-07 "OS/390 UNIX System Services Planning", in particular
+Chapter 6 on customizing the OE shell.
+
+GNU make for OS/390, which is recommended for the build of perl (as
+well as building CPAN modules and extensions), is available from the
+L</Tools>.
+
+Some people have reported encountering "Out of memory!" errors while
+trying to build Perl using GNU make binaries. If you encounter such
+trouble then try to download the source code kit and build GNU make
+from source to eliminate any such trouble. You might also find GNU make
+(as well as Perl and Apache) in the red-piece/book "Open Source Software
+for OS/390 UNIX", SG24-5944-00 from IBM.
+
+If instead of the recommended GNU make you would like to use the system
+supplied make program then be sure to install the default rules file
+properly via the shell command:
+
+ cp /samples/startup.mk /etc
+
+and be sure to also set the environment variable _C89_CCMODE=1 (exporting
+_C89_CCMODE=1 is also a good idea for users of GNU make).
+
+You might also want to have GNU groff for OS/390 installed before
+running the "make install" step for Perl.
+
+There is a syntax error in the /usr/include/sys/socket.h header file
+that IBM supplies with USS V2R7, V2R8, and possibly V2R9. The problem with
+the header file is that near the definition of the SO_REUSEPORT constant
+there is a spurious extra '/' character outside of a comment like so:
+
+ #define SO_REUSEPORT 0x0200 /* allow local address & port
+ reuse */ /
+
+You could edit that header yourself to remove that last '/', or you might
+note that Language Environment (LE) APAR PQ39997 describes the problem
+and PTF's UQ46272 and UQ46271 are the (R8 at least) fixes and apply them.
+If left unattended that syntax error will turn up as an inability for Perl
+to build its "Socket" extension.
+
+For successful testing you may need to turn on the sticky bit for your
+world readable /tmp directory if you have not already done so (see man chmod).
+
+=head2 Configure Perl on OS/390
+
+Once you've unpacked the distribution, run "sh Configure" (see INSTALL
+for a full discussion of the Configure options). There is a "hints" file
+for os390 that specifies the correct values for most things. Some things
+to watch out for include:
+
+=over 4
+
+=item *
+
+A message of the form:
+
+ (I see you are using the Korn shell. Some ksh's blow up on Configure,
+ mainly on older exotic systems. If yours does, try the Bourne shell instead.)
+
+is nothing to worry about at all.
+
+=item *
+
+Some of the parser default template files in /samples are needed in /etc.
+In particular be sure that you at least copy /samples/yyparse.c to /etc
+before running Perl's Configure. This step ensures successful extraction
+of EBCDIC versions of parser files such as perly.c, perly.h, and x2p/a2p.c.
+This has to be done before running Configure the first time. If you failed
+to do so then the easiest way to re-Configure Perl is to delete your
+misconfigured build root and re-extract the source from the tar ball.
+Then you must ensure that /etc/yyparse.c is properly in place before
+attempting to re-run Configure.
+
+=item *
+
+This port will support dynamic loading, but it is not selected by
+default. If you would like to experiment with dynamic loading then
+be sure to specify -Dusedl in the arguments to the Configure script.
+See the comments in hints/os390.sh for more information on dynamic loading.
+If you build with dynamic loading then you will need to add the
+$archlibexp/CORE directory to your LIBPATH environment variable in order
+for perl to work. See the config.sh file for the value of $archlibexp.
+If in trying to use Perl you see an error message similar to:
+
+ CEE3501S The module libperl.dll was not found.
+ From entry point __dllstaticinit at compile unit offset +00000194 at
+
+then your LIBPATH does not have the location of libperl.x and either
+libperl.dll or libperl.so in it. Add that directory to your LIBPATH and
+proceed.
+
+=item *
+
+Do not turn on the compiler optimization flag "-O". There is
+a bug in either the optimizer or perl that causes perl to
+not work correctly when the optimizer is on.
+
+=item *
+
+Some of the configuration files in /etc used by the
+networking APIs are either missing or have the wrong
+names. In particular, make sure that there's either
+an /etc/resolv.conf or an /etc/hosts, so that
+gethostbyname() works, and make sure that the file
+/etc/proto has been renamed to /etc/protocol (NOT
+/etc/protocols, as used by other Unix systems).
+You may have to look for things like HOSTNAME and DOMAINORIGIN
+in the "//'SYS1.TCPPARMS(TCPDATA)'" PDS member in order to
+properly set up your /etc networking files.
+
+=back
+
+=head2 Build, Test, Install Perl on OS/390
+
+Simply put:
+
+ sh Configure
+ make
+ make test
+
+if everything looks ok (see the next section for test/IVP diagnosis) then:
+
+ make install
+
+this last step may or may not require UID=0 privileges depending
+on how you answered the questions that Configure asked and whether
+or not you have write access to the directories you specified.
+
+=head2 Build Anomalies with Perl on OS/390
+
+"Out of memory!" messages during the build of Perl are most often fixed
+by re building the GNU make utility for OS/390 from a source code kit.
+
+Another memory limiting item to check is your MAXASSIZE parameter in your
+'SYS1.PARMLIB(BPXPRMxx)' data set (note too that as of V2R8 address space
+limits can be set on a per user ID basis in the USS segment of a RACF
+profile). People have reported successful builds of Perl with MAXASSIZE
+parameters as small as 503316480 (and it may be possible to build Perl
+with a MAXASSIZE smaller than that).
+
+Within USS your /etc/profile or $HOME/.profile may limit your ulimit
+settings. Check that the following command returns reasonable values:
+
+ ulimit -a
+
+To conserve memory you should have your compiler modules loaded into the
+Link Pack Area (LPA/ELPA) rather than in a link list or step lib.
+
+If the c89 compiler complains of syntax errors during the build of the
+Socket extension then be sure to fix the syntax error in the system
+header /usr/include/sys/socket.h.
+
+=head2 Testing Anomalies with Perl on OS/390
+
+The "make test" step runs a Perl Verification Procedure, usually before
+installation. You might encounter STDERR messages even during a successful
+run of "make test". Here is a guide to some of the more commonly seen
+anomalies:
+
+=over 4
+
+=item *
+
+A message of the form:
+
+ io/openpid...........CEE5210S The signal SIGHUP was received.
+ CEE5210S The signal SIGHUP was received.
+ CEE5210S The signal SIGHUP was received.
+ ok
+
+indicates that the t/io/openpid.t test of Perl has passed but done so
+with extraneous messages on stderr from CEE.
+
+=item *
+
+A message of the form:
+
+ lib/ftmp-security....File::Temp::_gettemp: Parent directory (/tmp/) is not safe
+ (sticky bit not set when world writable?) at lib/ftmp-security.t line 100
+ File::Temp::_gettemp: Parent directory (/tmp/) is not safe (sticky bit not
+ set when world writable?) at lib/ftmp-security.t line 100
+ ok
+
+indicates a problem with the permissions on your /tmp directory within the HFS.
+To correct that problem issue the command:
+
+ chmod a+t /tmp
+
+from an account with write access to the directory entry for /tmp.
+
+=item *
+
+Out of Memory!
+
+Recent perl test suite is quite memory hunrgy. In addition to the comments
+above on memory limitations it is also worth checking for _CEE_RUNOPTS
+in your environment. Perl now has (in miniperlmain.c) a C #pragma
+to set CEE run options, but the environment variable wins.
+
+The C code asks for:
+
+ #pragma runopts(HEAP(2M,500K,ANYWHERE,KEEP,8K,4K) STACK(,,ANY,) ALL31(ON))
+
+The important parts of that are the second argument (the increment) to HEAP,
+and allowing the stack to be "Above the (16M) line". If the heap
+increment is too small then when perl (for example loading unicode/Name.pl) tries
+to create a "big" (400K+) string it cannot fit in a single segment
+and you get "Out of Memory!" - even if there is still plenty of memory
+available.
+
+A related issue is use with perl's malloc. Perl's malloc uses C<sbrk()>
+to get memory, and C<sbrk()> is limited to the first allocation so in this
+case something like:
+
+ HEAP(8M,500K,ANYWHERE,KEEP,8K,4K)
+
+is needed to get through the test suite.
+
+
+=back
+
+=head2 Installation Anomalies with Perl on OS/390
+
+The installman script will try to run on OS/390. There will be fewer errors
+if you have a roff utility installed. You can obtain GNU groff from the
+Redbook SG24-5944-00 ftp site.
+
+=head2 Usage Hints for Perl on OS/390
+
+When using perl on OS/390 please keep in mind that the EBCDIC and ASCII
+character sets are different. See perlebcdic.pod for more on such character
+set issues. Perl builtin functions that may behave differently under
+EBCDIC are also mentioned in the perlport.pod document.
+
+Open Edition (UNIX System Services) from V2R8 onward does support
+#!/path/to/perl script invocation. There is a PTF available from
+IBM for V2R7 that will allow shell/kernel support for #!. USS
+releases prior to V2R7 did not support the #! means of script invocation.
+If you are running V2R6 or earlier then see:
+
+ head `whence perldoc`
+
+for an example of how to use the "eval exec" trick to ask the shell to
+have Perl run your scripts on those older releases of Unix System Services.
+
+If you are having trouble with square brackets then consider switching your
+rlogin or telnet client. Try to avoid older 3270 emulators and ISHELL for
+working with Perl on USS.
+
+=head2 Floating Point Anomalies with Perl on OS/390
+
+There appears to be a bug in the floating point implementation on S/390
+systems such that calling int() on the product of a number and a small
+magnitude number is not the same as calling int() on the quotient of
+that number and a large magnitude number. For example, in the following
+Perl code:
+
+ my $x = 100000.0;
+ my $y = int($x * 1e-5) * 1e5; # '0'
+ my $z = int($x / 1e+5) * 1e5; # '100000'
+ print "\$y is $y and \$z is $z\n"; # $y is 0 and $z is 100000
+
+Although one would expect the quantities $y and $z to be the same and equal
+to 100000 they will differ and instead will be 0 and 100000 respectively.
+
+The problem can be further examined in a roughly equivalent C program:
+
+ #include <stdio.h>
+ #include <math.h>
+ main()
+ {
+ double r1,r2;
+ double x = 100000.0;
+ double y = 0.0;
+ double z = 0.0;
+ x = 100000.0 * 1e-5;
+ r1 = modf (x,&y);
+ x = 100000.0 / 1e+5;
+ r2 = modf (x,&z);
+ printf("y is %e and z is %e\n",y*1e5,z*1e5);
+ /* y is 0.000000e+00 and z is 1.000000e+05 (with c89) */
+ }
+
+=head2 Modules and Extensions for Perl on OS/390
+
+Pure pure (that is non xs) modules may be installed via the usual:
+
+ perl Makefile.PL
+ make
+ make test
+ make install
+
+If you built perl with dynamic loading capability then that would also
+be the way to build xs based extensions. However, if you built perl with
+the default static linking you can still build xs based extensions for OS/390
+but you will need to follow the instructions in ExtUtils::MakeMaker for
+building statically linked perl binaries. In the simplest configurations
+building a static perl + xs extension boils down to:
+
+ perl Makefile.PL
+ make
+ make perl
+ make test
+ make install
+ make -f Makefile.aperl inst_perl MAP_TARGET=perl
+
+In most cases people have reported better results with GNU make rather
+than the system's /bin/make program, whether for plain modules or for
+xs based extensions.
+
+If the make process encounters trouble with either compilation or
+linking then try setting the _C89_CCMODE to 1. Assuming sh is your
+login shell then run:
+
+ export _C89_CCMODE=1
+
+If tcsh is your login shell then use the setenv command.
+
+=head1 AUTHORS
+
+David Fiander and Peter Prymmer with thanks to Dennis Longnecker
+and William Raffloer for valuable reports, LPAR and PTF feedback.
+Thanks to Mike MacIsaac and Egon Terwedow for SG24-5944-00.
+Thanks to Ignasi Roca for pointing out the floating point problems.
+Thanks to John Goodyear for dynamic loading help.
+
+=head1 SEE ALSO
+
+L<INSTALL>, L<perlport>, L<perlebcdic>, L<ExtUtils::MakeMaker>.
+
+ http://www.ibm.com/servers/eserver/zseries/zos/unix/bpxa1toy.html
+
+ http://www.redbooks.ibm.com/redbooks/SG245944.html
+
+ http://www.ibm.com/servers/eserver/zseries/zos/unix/bpxa1ty1.html#opensrc
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl-mvs/
+
+ http://publibz.boulder.ibm.com:80/cgi-bin/bookmgr_OS390/BOOKS/ceea3030/
+
+ http://publibz.boulder.ibm.com:80/cgi-bin/bookmgr_OS390/BOOKS/CBCUG030/
+
+=head2 Mailing list for Perl on OS/390
+
+If you are interested in the VM/ESA, z/OS (formerly known as OS/390)
+and POSIX-BC (BS2000) ports of Perl then see the perl-mvs mailing list.
+To subscribe, send an empty message to perl-mvs-subscribe@perl.org.
+
+See also:
+
+ http://lists.perl.org/showlist.cgi?name=perl-mvs
+
+There are web archives of the mailing list at:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl-mvs/
+ http://archive.develooper.com/perl-mvs@perl.org/
+
+=head1 HISTORY
+
+This document was originally written by David Fiander for the 5.005
+release of Perl.
+
+This document was podified for the 5.005_03 release of Perl 11 March 1999.
+
+Updated 28 November 2001 for broken URLs.
+
+Updated 12 November 2000 for the 5.7.1 release of Perl.
+
+Updated 15 January 2001 for the 5.7.1 release of Perl.
+
+Updated 24 January 2001 to mention dynamic loading.
+
+Updated 12 March 2001 to mention //'SYS1.TCPPARMS(TCPDATA)'.
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlos400.pod b/Master/tlpkg/tlperl/lib/pods/perlos400.pod
new file mode 100644
index 00000000000..cd789166955
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlos400.pod
@@ -0,0 +1,120 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.os400 - Perl version 5 on OS/400
+
+=head1 DESCRIPTION
+
+This document describes various features of IBM's OS/400 operating
+system that will affect how Perl version 5 (hereafter just Perl) is
+compiled and/or runs.
+
+By far the easiest way to build Perl for OS/400 is to use the PASE
+(Portable Application Solutions Environment), for more information see
+http://www.iseries.ibm.com/developer/factory/pase/index.html
+This environment allows one to use AIX APIs while programming, and it
+provides a runtime that allows AIX binaries to execute directly on the
+PowerPC iSeries.
+
+=head2 Compiling Perl for OS/400 PASE
+
+The recommended way to build Perl for the OS/400 PASE is to build the
+Perl 5 source code (release 5.8.1 or later) under AIX.
+
+The trick is to give a special parameter to the Configure shell script
+when running it on AIX:
+
+ sh Configure -DPASE ...
+
+The default installation directory of Perl under PASE is /QOpenSys/perl.
+This can be modified if needed with Configure parameter -Dprefix=/some/dir.
+
+Starting from OS/400 V5R2 the IBM Visual Age compiler is supported
+on OS/400 PASE, so it is possible to build Perl natively on OS/400.
+The easier way, however, is to compile in AIX, as just described.
+
+If you don't want to install the compiled Perl in AIX into /QOpenSys
+(for packaging it before copying it to PASE), you can use a Configure
+parameter: -Dinstallprefix=/tmp/QOpenSys/perl. This will cause the
+"make install" to install everything into that directory, while the
+installed files still think they are (will be) in /QOpenSys/perl.
+
+If building natively on PASE, please do the build under the /QOpenSys
+directory, since Perl is happier when built on a case sensitive filesystem.
+
+=head2 Installing Perl in OS/400 PASE
+
+If you are compiling on AIX, simply do a "make install" on the AIX box.
+Once the install finishes, tar up the /QOpenSys/perl directory. Transfer
+the tarball to the OS/400 using FTP with the following commands:
+
+ > binary
+ > site namefmt 1
+ > put perl.tar /QOpenSys
+
+Once you have it on, simply bring up a PASE shell and extract the tarball.
+
+If you are compiling in PASE, then "make install" is the only thing you
+will need to do.
+
+The default path for perl binary is /QOpenSys/perl/bin/perl. You'll
+want to symlink /QOpenSys/usr/bin/perl to this file so you don't have
+to modify your path.
+
+=head2 Using Perl in OS/400 PASE
+
+Perl in PASE may be used in the same manner as you would use Perl on AIX.
+
+Scripts starting with #!/usr/bin/perl should work if you have
+/QOpenSys/usr/bin/perl symlinked to your perl binary. This will not
+work if you've done a setuid/setgid or have environment variable
+PASE_EXEC_QOPENSYS="N". If you have V5R1, you'll need to get the
+latest PTFs to have this feature. Scripts starting with
+#!/QOpenSys/perl/bin/perl should always work.
+
+=head2 Known Problems
+
+When compiling in PASE, there is no "oslevel" command. Therefore,
+you may want to create a script called "oslevel" that echoes the
+level of AIX that your version of PASE runtime supports. If you're
+unsure, consult your documentation or use "4.3.3.0".
+
+If you have test cases that fail, check for the existence of spool files.
+The test case may be trying to use a syscall that is not implemented
+in PASE. To avoid the SIGILL, try setting the PASE_SYSCALL_NOSIGILL
+environment variable or have a handler for the SIGILL. If you can
+compile programs for PASE, run the config script and edit config.sh
+when it gives you the option. If you want to remove fchdir(), which
+isn't implement in V5R1, simply change the line that says:
+
+d_fchdir='define'
+
+to
+
+d_fchdir='undef'
+
+and then compile Perl. The places where fchdir() is used have
+alternatives for systems that do not have fchdir() available.
+
+=head2 Perl on ILE
+
+There exists a port of Perl to the ILE environment. This port, however,
+is based quite an old release of Perl, Perl 5.00502 (August 1998).
+(As of July 2002 the latest release of Perl is 5.8.0, and even 5.6.1
+has been out since April 2001.) If you need to run Perl on ILE, though,
+you may need this older port: http://www.cpan.org/ports/#os400
+Note that any Perl release later than 5.00502 has not been ported to ILE.
+
+If you need to use Perl in the ILE environment, you may want to consider
+using Qp2RunPase() to call the PASE version of Perl.
+
+=head1 AUTHORS
+
+Jarkko Hietaniemi <jhi@iki.fi>
+Bryan Logan <bryanlog@us.ibm.com>
+David Larson <larson1@us.ibm.com>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlpacktut.pod b/Master/tlpkg/tlperl/lib/pods/perlpacktut.pod
new file mode 100644
index 00000000000..7d2126a0eaa
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlpacktut.pod
@@ -0,0 +1,1266 @@
+=head1 NAME
+
+perlpacktut - tutorial on C<pack> and C<unpack>
+
+=head1 DESCRIPTION
+
+C<pack> and C<unpack> are two functions for transforming data according
+to a user-defined template, between the guarded way Perl stores values
+and some well-defined representation as might be required in the
+environment of a Perl program. Unfortunately, they're also two of
+the most misunderstood and most often overlooked functions that Perl
+provides. This tutorial will demystify them for you.
+
+
+=head1 The Basic Principle
+
+Most programming languages don't shelter the memory where variables are
+stored. In C, for instance, you can take the address of some variable,
+and the C<sizeof> operator tells you how many bytes are allocated to
+the variable. Using the address and the size, you may access the storage
+to your heart's content.
+
+In Perl, you just can't access memory at random, but the structural and
+representational conversion provided by C<pack> and C<unpack> is an
+excellent alternative. The C<pack> function converts values to a byte
+sequence containing representations according to a given specification,
+the so-called "template" argument. C<unpack> is the reverse process,
+deriving some values from the contents of a string of bytes. (Be cautioned,
+however, that not all that has been packed together can be neatly unpacked -
+a very common experience as seasoned travellers are likely to confirm.)
+
+Why, you may ask, would you need a chunk of memory containing some values
+in binary representation? One good reason is input and output accessing
+some file, a device, or a network connection, whereby this binary
+representation is either forced on you or will give you some benefit
+in processing. Another cause is passing data to some system call that
+is not available as a Perl function: C<syscall> requires you to provide
+parameters stored in the way it happens in a C program. Even text processing
+(as shown in the next section) may be simplified with judicious usage
+of these two functions.
+
+To see how (un)packing works, we'll start with a simple template
+code where the conversion is in low gear: between the contents of a byte
+sequence and a string of hexadecimal digits. Let's use C<unpack>, since
+this is likely to remind you of a dump program, or some desperate last
+message unfortunate programs are wont to throw at you before they expire
+into the wild blue yonder. Assuming that the variable C<$mem> holds a
+sequence of bytes that we'd like to inspect without assuming anything
+about its meaning, we can write
+
+ my( $hex ) = unpack( 'H*', $mem );
+ print "$hex\n";
+
+whereupon we might see something like this, with each pair of hex digits
+corresponding to a byte:
+
+ 41204d414e204120504c414e20412043414e414c2050414e414d41
+
+What was in this chunk of memory? Numbers, characters, or a mixture of
+both? Assuming that we're on a computer where ASCII (or some similar)
+encoding is used: hexadecimal values in the range C<0x40> - C<0x5A>
+indicate an uppercase letter, and C<0x20> encodes a space. So we might
+assume it is a piece of text, which some are able to read like a tabloid;
+but others will have to get hold of an ASCII table and relive that
+firstgrader feeling. Not caring too much about which way to read this,
+we note that C<unpack> with the template code C<H> converts the contents
+of a sequence of bytes into the customary hexadecimal notation. Since
+"a sequence of" is a pretty vague indication of quantity, C<H> has been
+defined to convert just a single hexadecimal digit unless it is followed
+by a repeat count. An asterisk for the repeat count means to use whatever
+remains.
+
+The inverse operation - packing byte contents from a string of hexadecimal
+digits - is just as easily written. For instance:
+
+ my $s = pack( 'H2' x 10, map { "3$_" } ( 0..9 ) );
+ print "$s\n";
+
+Since we feed a list of ten 2-digit hexadecimal strings to C<pack>, the
+pack template should contain ten pack codes. If this is run on a computer
+with ASCII character coding, it will print C<0123456789>.
+
+
+=head1 Packing Text
+
+Let's suppose you've got to read in a data file like this:
+
+ Date |Description | Income|Expenditure
+ 01/24/2001 Ahmed's Camel Emporium 1147.99
+ 01/28/2001 Flea spray 24.99
+ 01/29/2001 Camel rides to tourists 235.00
+
+How do we do it? You might think first to use C<split>; however, since
+C<split> collapses blank fields, you'll never know whether a record was
+income or expenditure. Oops. Well, you could always use C<substr>:
+
+ while (<>) {
+ my $date = substr($_, 0, 11);
+ my $desc = substr($_, 12, 27);
+ my $income = substr($_, 40, 7);
+ my $expend = substr($_, 52, 7);
+ ...
+ }
+
+It's not really a barrel of laughs, is it? In fact, it's worse than it
+may seem; the eagle-eyed may notice that the first field should only be
+10 characters wide, and the error has propagated right through the other
+numbers - which we've had to count by hand. So it's error-prone as well
+as horribly unfriendly.
+
+Or maybe we could use regular expressions:
+
+ while (<>) {
+ my($date, $desc, $income, $expend) =
+ m|(\d\d/\d\d/\d{4}) (.{27}) (.{7})(.*)|;
+ ...
+ }
+
+Urgh. Well, it's a bit better, but - well, would you want to maintain
+that?
+
+Hey, isn't Perl supposed to make this sort of thing easy? Well, it does,
+if you use the right tools. C<pack> and C<unpack> are designed to help
+you out when dealing with fixed-width data like the above. Let's have a
+look at a solution with C<unpack>:
+
+ while (<>) {
+ my($date, $desc, $income, $expend) = unpack("A10xA27xA7A*", $_);
+ ...
+ }
+
+That looks a bit nicer; but we've got to take apart that weird template.
+Where did I pull that out of?
+
+OK, let's have a look at some of our data again; in fact, we'll include
+the headers, and a handy ruler so we can keep track of where we are.
+
+ 1 2 3 4 5
+ 1234567890123456789012345678901234567890123456789012345678
+ Date |Description | Income|Expenditure
+ 01/28/2001 Flea spray 24.99
+ 01/29/2001 Camel rides to tourists 235.00
+
+From this, we can see that the date column stretches from column 1 to
+column 10 - ten characters wide. The C<pack>-ese for "character" is
+C<A>, and ten of them are C<A10>. So if we just wanted to extract the
+dates, we could say this:
+
+ my($date) = unpack("A10", $_);
+
+OK, what's next? Between the date and the description is a blank column;
+we want to skip over that. The C<x> template means "skip forward", so we
+want one of those. Next, we have another batch of characters, from 12 to
+38. That's 27 more characters, hence C<A27>. (Don't make the fencepost
+error - there are 27 characters between 12 and 38, not 26. Count 'em!)
+
+Now we skip another character and pick up the next 7 characters:
+
+ my($date,$description,$income) = unpack("A10xA27xA7", $_);
+
+Now comes the clever bit. Lines in our ledger which are just income and
+not expenditure might end at column 46. Hence, we don't want to tell our
+C<unpack> pattern that we B<need> to find another 12 characters; we'll
+just say "if there's anything left, take it". As you might guess from
+regular expressions, that's what the C<*> means: "use everything
+remaining".
+
+=over 3
+
+=item *
+
+Be warned, though, that unlike regular expressions, if the C<unpack>
+template doesn't match the incoming data, Perl will scream and die.
+
+=back
+
+
+Hence, putting it all together:
+
+ my($date,$description,$income,$expend) = unpack("A10xA27xA7xA*", $_);
+
+Now, that's our data parsed. I suppose what we might want to do now is
+total up our income and expenditure, and add another line to the end of
+our ledger - in the same format - saying how much we've brought in and
+how much we've spent:
+
+ while (<>) {
+ my($date, $desc, $income, $expend) = unpack("A10xA27xA7xA*", $_);
+ $tot_income += $income;
+ $tot_expend += $expend;
+ }
+
+ $tot_income = sprintf("%.2f", $tot_income); # Get them into
+ $tot_expend = sprintf("%.2f", $tot_expend); # "financial" format
+
+ $date = POSIX::strftime("%m/%d/%Y", localtime);
+
+ # OK, let's go:
+
+ print pack("A10xA27xA7xA*", $date, "Totals", $tot_income, $tot_expend);
+
+Oh, hmm. That didn't quite work. Let's see what happened:
+
+ 01/24/2001 Ahmed's Camel Emporium 1147.99
+ 01/28/2001 Flea spray 24.99
+ 01/29/2001 Camel rides to tourists 1235.00
+ 03/23/2001Totals 1235.001172.98
+
+OK, it's a start, but what happened to the spaces? We put C<x>, didn't
+we? Shouldn't it skip forward? Let's look at what L<perlfunc/pack> says:
+
+ x A null byte.
+
+Urgh. No wonder. There's a big difference between "a null byte",
+character zero, and "a space", character 32. Perl's put something
+between the date and the description - but unfortunately, we can't see
+it!
+
+What we actually need to do is expand the width of the fields. The C<A>
+format pads any non-existent characters with spaces, so we can use the
+additional spaces to line up our fields, like this:
+
+ print pack("A11 A28 A8 A*", $date, "Totals", $tot_income, $tot_expend);
+
+(Note that you can put spaces in the template to make it more readable,
+but they don't translate to spaces in the output.) Here's what we got
+this time:
+
+ 01/24/2001 Ahmed's Camel Emporium 1147.99
+ 01/28/2001 Flea spray 24.99
+ 01/29/2001 Camel rides to tourists 1235.00
+ 03/23/2001 Totals 1235.00 1172.98
+
+That's a bit better, but we still have that last column which needs to
+be moved further over. There's an easy way to fix this up:
+unfortunately, we can't get C<pack> to right-justify our fields, but we
+can get C<sprintf> to do it:
+
+ $tot_income = sprintf("%.2f", $tot_income);
+ $tot_expend = sprintf("%12.2f", $tot_expend);
+ $date = POSIX::strftime("%m/%d/%Y", localtime);
+ print pack("A11 A28 A8 A*", $date, "Totals", $tot_income, $tot_expend);
+
+This time we get the right answer:
+
+ 01/28/2001 Flea spray 24.99
+ 01/29/2001 Camel rides to tourists 1235.00
+ 03/23/2001 Totals 1235.00 1172.98
+
+So that's how we consume and produce fixed-width data. Let's recap what
+we've seen of C<pack> and C<unpack> so far:
+
+=over 3
+
+=item *
+
+Use C<pack> to go from several pieces of data to one fixed-width
+version; use C<unpack> to turn a fixed-width-format string into several
+pieces of data.
+
+=item *
+
+The pack format C<A> means "any character"; if you're C<pack>ing and
+you've run out of things to pack, C<pack> will fill the rest up with
+spaces.
+
+=item *
+
+C<x> means "skip a byte" when C<unpack>ing; when C<pack>ing, it means
+"introduce a null byte" - that's probably not what you mean if you're
+dealing with plain text.
+
+=item *
+
+You can follow the formats with numbers to say how many characters
+should be affected by that format: C<A12> means "take 12 characters";
+C<x6> means "skip 6 bytes" or "character 0, 6 times".
+
+=item *
+
+Instead of a number, you can use C<*> to mean "consume everything else
+left".
+
+B<Warning>: when packing multiple pieces of data, C<*> only means
+"consume all of the current piece of data". That's to say
+
+ pack("A*A*", $one, $two)
+
+packs all of C<$one> into the first C<A*> and then all of C<$two> into
+the second. This is a general principle: each format character
+corresponds to one piece of data to be C<pack>ed.
+
+=back
+
+
+
+=head1 Packing Numbers
+
+So much for textual data. Let's get onto the meaty stuff that C<pack>
+and C<unpack> are best at: handling binary formats for numbers. There is,
+of course, not just one binary format - life would be too simple - but
+Perl will do all the finicky labor for you.
+
+
+=head2 Integers
+
+Packing and unpacking numbers implies conversion to and from some
+I<specific> binary representation. Leaving floating point numbers
+aside for the moment, the salient properties of any such representation
+are:
+
+=over 4
+
+=item *
+
+the number of bytes used for storing the integer,
+
+=item *
+
+whether the contents are interpreted as a signed or unsigned number,
+
+=item *
+
+the byte ordering: whether the first byte is the least or most
+significant byte (or: little-endian or big-endian, respectively).
+
+=back
+
+So, for instance, to pack 20302 to a signed 16 bit integer in your
+computer's representation you write
+
+ my $ps = pack( 's', 20302 );
+
+Again, the result is a string, now containing 2 bytes. If you print
+this string (which is, generally, not recommended) you might see
+C<ON> or C<NO> (depending on your system's byte ordering) - or something
+entirely different if your computer doesn't use ASCII character encoding.
+Unpacking C<$ps> with the same template returns the original integer value:
+
+ my( $s ) = unpack( 's', $ps );
+
+This is true for all numeric template codes. But don't expect miracles:
+if the packed value exceeds the allotted byte capacity, high order bits
+are silently discarded, and unpack certainly won't be able to pull them
+back out of some magic hat. And, when you pack using a signed template
+code such as C<s>, an excess value may result in the sign bit
+getting set, and unpacking this will smartly return a negative value.
+
+16 bits won't get you too far with integers, but there is C<l> and C<L>
+for signed and unsigned 32-bit integers. And if this is not enough and
+your system supports 64 bit integers you can push the limits much closer
+to infinity with pack codes C<q> and C<Q>. A notable exception is provided
+by pack codes C<i> and C<I> for signed and unsigned integers of the
+"local custom" variety: Such an integer will take up as many bytes as
+a local C compiler returns for C<sizeof(int)>, but it'll use I<at least>
+32 bits.
+
+Each of the integer pack codes C<sSlLqQ> results in a fixed number of bytes,
+no matter where you execute your program. This may be useful for some
+applications, but it does not provide for a portable way to pass data
+structures between Perl and C programs (bound to happen when you call
+XS extensions or the Perl function C<syscall>), or when you read or
+write binary files. What you'll need in this case are template codes that
+depend on what your local C compiler compiles when you code C<short> or
+C<unsigned long>, for instance. These codes and their corresponding
+byte lengths are shown in the table below. Since the C standard leaves
+much leeway with respect to the relative sizes of these data types, actual
+values may vary, and that's why the values are given as expressions in
+C and Perl. (If you'd like to use values from C<%Config> in your program
+you have to import it with C<use Config>.)
+
+ signed unsigned byte length in C byte length in Perl
+ s! S! sizeof(short) $Config{shortsize}
+ i! I! sizeof(int) $Config{intsize}
+ l! L! sizeof(long) $Config{longsize}
+ q! Q! sizeof(long long) $Config{longlongsize}
+
+The C<i!> and C<I!> codes aren't different from C<i> and C<I>; they are
+tolerated for completeness' sake.
+
+
+=head2 Unpacking a Stack Frame
+
+Requesting a particular byte ordering may be necessary when you work with
+binary data coming from some specific architecture whereas your program could
+run on a totally different system. As an example, assume you have 24 bytes
+containing a stack frame as it happens on an Intel 8086:
+
+ +---------+ +----+----+ +---------+
+ TOS: | IP | TOS+4:| FL | FH | FLAGS TOS+14:| SI |
+ +---------+ +----+----+ +---------+
+ | CS | | AL | AH | AX | DI |
+ +---------+ +----+----+ +---------+
+ | BL | BH | BX | BP |
+ +----+----+ +---------+
+ | CL | CH | CX | DS |
+ +----+----+ +---------+
+ | DL | DH | DX | ES |
+ +----+----+ +---------+
+
+First, we note that this time-honored 16-bit CPU uses little-endian order,
+and that's why the low order byte is stored at the lower address. To
+unpack such a (unsigned) short we'll have to use code C<v>. A repeat
+count unpacks all 12 shorts:
+
+ my( $ip, $cs, $flags, $ax, $bx, $cd, $dx, $si, $di, $bp, $ds, $es ) =
+ unpack( 'v12', $frame );
+
+Alternatively, we could have used C<C> to unpack the individually
+accessible byte registers FL, FH, AL, AH, etc.:
+
+ my( $fl, $fh, $al, $ah, $bl, $bh, $cl, $ch, $dl, $dh ) =
+ unpack( 'C10', substr( $frame, 4, 10 ) );
+
+It would be nice if we could do this in one fell swoop: unpack a short,
+back up a little, and then unpack 2 bytes. Since Perl I<is> nice, it
+proffers the template code C<X> to back up one byte. Putting this all
+together, we may now write:
+
+ my( $ip, $cs,
+ $flags,$fl,$fh,
+ $ax,$al,$ah, $bx,$bl,$bh, $cx,$cl,$ch, $dx,$dl,$dh,
+ $si, $di, $bp, $ds, $es ) =
+ unpack( 'v2' . ('vXXCC' x 5) . 'v5', $frame );
+
+(The clumsy construction of the template can be avoided - just read on!)
+
+We've taken some pains to construct the template so that it matches
+the contents of our frame buffer. Otherwise we'd either get undefined values,
+or C<unpack> could not unpack all. If C<pack> runs out of items, it will
+supply null strings (which are coerced into zeroes whenever the pack code
+says so).
+
+
+=head2 How to Eat an Egg on a Net
+
+The pack code for big-endian (high order byte at the lowest address) is
+C<n> for 16 bit and C<N> for 32 bit integers. You use these codes
+if you know that your data comes from a compliant architecture, but,
+surprisingly enough, you should also use these pack codes if you
+exchange binary data, across the network, with some system that you
+know next to nothing about. The simple reason is that this
+order has been chosen as the I<network order>, and all standard-fearing
+programs ought to follow this convention. (This is, of course, a stern
+backing for one of the Lilliputian parties and may well influence the
+political development there.) So, if the protocol expects you to send
+a message by sending the length first, followed by just so many bytes,
+you could write:
+
+ my $buf = pack( 'N', length( $msg ) ) . $msg;
+
+or even:
+
+ my $buf = pack( 'NA*', length( $msg ), $msg );
+
+and pass C<$buf> to your send routine. Some protocols demand that the
+count should include the length of the count itself: then just add 4
+to the data length. (But make sure to read L<"Lengths and Widths"> before
+you really code this!)
+
+
+=head2 Byte-order modifiers
+
+In the previous sections we've learned how to use C<n>, C<N>, C<v> and
+C<V> to pack and unpack integers with big- or little-endian byte-order.
+While this is nice, it's still rather limited because it leaves out all
+kinds of signed integers as well as 64-bit integers. For example, if you
+wanted to unpack a sequence of signed big-endian 16-bit integers in a
+platform-independent way, you would have to write:
+
+ my @data = unpack 's*', pack 'S*', unpack 'n*', $buf;
+
+This is ugly. As of Perl 5.9.2, there's a much nicer way to express your
+desire for a certain byte-order: the C<E<gt>> and C<E<lt>> modifiers.
+C<E<gt>> is the big-endian modifier, while C<E<lt>> is the little-endian
+modifier. Using them, we could rewrite the above code as:
+
+ my @data = unpack 's>*', $buf;
+
+As you can see, the "big end" of the arrow touches the C<s>, which is a
+nice way to remember that C<E<gt>> is the big-endian modifier. The same
+obviously works for C<E<lt>>, where the "little end" touches the code.
+
+You will probably find these modifiers even more useful if you have
+to deal with big- or little-endian C structures. Be sure to read
+L<"Packing and Unpacking C Structures"> for more on that.
+
+
+=head2 Floating point Numbers
+
+For packing floating point numbers you have the choice between the
+pack codes C<f>, C<d>, C<F> and C<D>. C<f> and C<d> pack into (or unpack
+from) single-precision or double-precision representation as it is provided
+by your system. If your systems supports it, C<D> can be used to pack and
+unpack extended-precision floating point values (C<long double>), which
+can offer even more resolution than C<f> or C<d>. C<F> packs an C<NV>,
+which is the floating point type used by Perl internally. (There
+is no such thing as a network representation for reals, so if you want
+to send your real numbers across computer boundaries, you'd better stick
+to ASCII representation, unless you're absolutely sure what's on the other
+end of the line. For the even more adventuresome, you can use the byte-order
+modifiers from the previous section also on floating point codes.)
+
+
+
+=head1 Exotic Templates
+
+
+=head2 Bit Strings
+
+Bits are the atoms in the memory world. Access to individual bits may
+have to be used either as a last resort or because it is the most
+convenient way to handle your data. Bit string (un)packing converts
+between strings containing a series of C<0> and C<1> characters and
+a sequence of bytes each containing a group of 8 bits. This is almost
+as simple as it sounds, except that there are two ways the contents of
+a byte may be written as a bit string. Let's have a look at an annotated
+byte:
+
+ 7 6 5 4 3 2 1 0
+ +-----------------+
+ | 1 0 0 0 1 1 0 0 |
+ +-----------------+
+ MSB LSB
+
+It's egg-eating all over again: Some think that as a bit string this should
+be written "10001100" i.e. beginning with the most significant bit, others
+insist on "00110001". Well, Perl isn't biased, so that's why we have two bit
+string codes:
+
+ $byte = pack( 'B8', '10001100' ); # start with MSB
+ $byte = pack( 'b8', '00110001' ); # start with LSB
+
+It is not possible to pack or unpack bit fields - just integral bytes.
+C<pack> always starts at the next byte boundary and "rounds up" to the
+next multiple of 8 by adding zero bits as required. (If you do want bit
+fields, there is L<perlfunc/vec>. Or you could implement bit field
+handling at the character string level, using split, substr, and
+concatenation on unpacked bit strings.)
+
+To illustrate unpacking for bit strings, we'll decompose a simple
+status register (a "-" stands for a "reserved" bit):
+
+ +-----------------+-----------------+
+ | S Z - A - P - C | - - - - O D I T |
+ +-----------------+-----------------+
+ MSB LSB MSB LSB
+
+Converting these two bytes to a string can be done with the unpack
+template C<'b16'>. To obtain the individual bit values from the bit
+string we use C<split> with the "empty" separator pattern which dissects
+into individual characters. Bit values from the "reserved" positions are
+simply assigned to C<undef>, a convenient notation for "I don't care where
+this goes".
+
+ ($carry, undef, $parity, undef, $auxcarry, undef, $zero, $sign,
+ $trace, $interrupt, $direction, $overflow) =
+ split( //, unpack( 'b16', $status ) );
+
+We could have used an unpack template C<'b12'> just as well, since the
+last 4 bits can be ignored anyway.
+
+
+=head2 Uuencoding
+
+Another odd-man-out in the template alphabet is C<u>, which packs an
+"uuencoded string". ("uu" is short for Unix-to-Unix.) Chances are that
+you won't ever need this encoding technique which was invented to overcome
+the shortcomings of old-fashioned transmission mediums that do not support
+other than simple ASCII data. The essential recipe is simple: Take three
+bytes, or 24 bits. Split them into 4 six-packs, adding a space (0x20) to
+each. Repeat until all of the data is blended. Fold groups of 4 bytes into
+lines no longer than 60 and garnish them in front with the original byte count
+(incremented by 0x20) and a C<"\n"> at the end. - The C<pack> chef will
+prepare this for you, a la minute, when you select pack code C<u> on the menu:
+
+ my $uubuf = pack( 'u', $bindat );
+
+A repeat count after C<u> sets the number of bytes to put into an
+uuencoded line, which is the maximum of 45 by default, but could be
+set to some (smaller) integer multiple of three. C<unpack> simply ignores
+the repeat count.
+
+
+=head2 Doing Sums
+
+An even stranger template code is C<%>E<lt>I<number>E<gt>. First, because
+it's used as a prefix to some other template code. Second, because it
+cannot be used in C<pack> at all, and third, in C<unpack>, doesn't return the
+data as defined by the template code it precedes. Instead it'll give you an
+integer of I<number> bits that is computed from the data value by
+doing sums. For numeric unpack codes, no big feat is achieved:
+
+ my $buf = pack( 'iii', 100, 20, 3 );
+ print unpack( '%32i3', $buf ), "\n"; # prints 123
+
+For string values, C<%> returns the sum of the byte values saving
+you the trouble of a sum loop with C<substr> and C<ord>:
+
+ print unpack( '%32A*', "\x01\x10" ), "\n"; # prints 17
+
+Although the C<%> code is documented as returning a "checksum":
+don't put your trust in such values! Even when applied to a small number
+of bytes, they won't guarantee a noticeable Hamming distance.
+
+In connection with C<b> or C<B>, C<%> simply adds bits, and this can be put
+to good use to count set bits efficiently:
+
+ my $bitcount = unpack( '%32b*', $mask );
+
+And an even parity bit can be determined like this:
+
+ my $evenparity = unpack( '%1b*', $mask );
+
+
+=head2 Unicode
+
+Unicode is a character set that can represent most characters in most of
+the world's languages, providing room for over one million different
+characters. Unicode 3.1 specifies 94,140 characters: The Basic Latin
+characters are assigned to the numbers 0 - 127. The Latin-1 Supplement with
+characters that are used in several European languages is in the next
+range, up to 255. After some more Latin extensions we find the character
+sets from languages using non-Roman alphabets, interspersed with a
+variety of symbol sets such as currency symbols, Zapf Dingbats or Braille.
+(You might want to visit L<http://www.unicode.org/> for a look at some of
+them - my personal favourites are Telugu and Kannada.)
+
+The Unicode character sets associates characters with integers. Encoding
+these numbers in an equal number of bytes would more than double the
+requirements for storing texts written in Latin alphabets.
+The UTF-8 encoding avoids this by storing the most common (from a western
+point of view) characters in a single byte while encoding the rarer
+ones in three or more bytes.
+
+Perl uses UTF-8, internally, for most Unicode strings.
+
+So what has this got to do with C<pack>? Well, if you want to compose a
+Unicode string (that is internally encoded as UTF-8), you can do so by
+using template code C<U>. As an example, let's produce the Euro currency
+symbol (code number 0x20AC):
+
+ $UTF8{Euro} = pack( 'U', 0x20AC );
+ # Equivalent to: $UTF8{Euro} = "\x{20ac}";
+
+Inspecting C<$UTF8{Euro}> shows that it contains 3 bytes:
+"\xe2\x82\xac". However, it contains only 1 character, number 0x20AC.
+The round trip can be completed with C<unpack>:
+
+ $Unicode{Euro} = unpack( 'U', $UTF8{Euro} );
+
+Unpacking using the C<U> template code also works on UTF-8 encoded byte
+strings.
+
+Usually you'll want to pack or unpack UTF-8 strings:
+
+ # pack and unpack the Hebrew alphabet
+ my $alefbet = pack( 'U*', 0x05d0..0x05ea );
+ my @hebrew = unpack( 'U*', $utf );
+
+Please note: in the general case, you're better off using
+Encode::decode_utf8 to decode a UTF-8 encoded byte string to a Perl
+Unicode string, and Encode::encode_utf8 to encode a Perl Unicode string
+to UTF-8 bytes. These functions provide means of handling invalid byte
+sequences and generally have a friendlier interface.
+
+=head2 Another Portable Binary Encoding
+
+The pack code C<w> has been added to support a portable binary data
+encoding scheme that goes way beyond simple integers. (Details can
+be found at L<http://Casbah.org/>, the Scarab project.) A BER (Binary Encoded
+Representation) compressed unsigned integer stores base 128
+digits, most significant digit first, with as few digits as possible.
+Bit eight (the high bit) is set on each byte except the last. There
+is no size limit to BER encoding, but Perl won't go to extremes.
+
+ my $berbuf = pack( 'w*', 1, 128, 128+1, 128*128+127 );
+
+A hex dump of C<$berbuf>, with spaces inserted at the right places,
+shows 01 8100 8101 81807F. Since the last byte is always less than
+128, C<unpack> knows where to stop.
+
+
+=head1 Template Grouping
+
+Prior to Perl 5.8, repetitions of templates had to be made by
+C<x>-multiplication of template strings. Now there is a better way as
+we may use the pack codes C<(> and C<)> combined with a repeat count.
+The C<unpack> template from the Stack Frame example can simply
+be written like this:
+
+ unpack( 'v2 (vXXCC)5 v5', $frame )
+
+Let's explore this feature a little more. We'll begin with the equivalent of
+
+ join( '', map( substr( $_, 0, 1 ), @str ) )
+
+which returns a string consisting of the first character from each string.
+Using pack, we can write
+
+ pack( '(A)'.@str, @str )
+
+or, because a repeat count C<*> means "repeat as often as required",
+simply
+
+ pack( '(A)*', @str )
+
+(Note that the template C<A*> would only have packed C<$str[0]> in full
+length.)
+
+To pack dates stored as triplets ( day, month, year ) in an array C<@dates>
+into a sequence of byte, byte, short integer we can write
+
+ $pd = pack( '(CCS)*', map( @$_, @dates ) );
+
+To swap pairs of characters in a string (with even length) one could use
+several techniques. First, let's use C<x> and C<X> to skip forward and back:
+
+ $s = pack( '(A)*', unpack( '(xAXXAx)*', $s ) );
+
+We can also use C<@> to jump to an offset, with 0 being the position where
+we were when the last C<(> was encountered:
+
+ $s = pack( '(A)*', unpack( '(@1A @0A @2)*', $s ) );
+
+Finally, there is also an entirely different approach by unpacking big
+endian shorts and packing them in the reverse byte order:
+
+ $s = pack( '(v)*', unpack( '(n)*', $s );
+
+
+=head1 Lengths and Widths
+
+=head2 String Lengths
+
+In the previous section we've seen a network message that was constructed
+by prefixing the binary message length to the actual message. You'll find
+that packing a length followed by so many bytes of data is a
+frequently used recipe since appending a null byte won't work
+if a null byte may be part of the data. Here is an example where both
+techniques are used: after two null terminated strings with source and
+destination address, a Short Message (to a mobile phone) is sent after
+a length byte:
+
+ my $msg = pack( 'Z*Z*CA*', $src, $dst, length( $sm ), $sm );
+
+Unpacking this message can be done with the same template:
+
+ ( $src, $dst, $len, $sm ) = unpack( 'Z*Z*CA*', $msg );
+
+There's a subtle trap lurking in the offing: Adding another field after
+the Short Message (in variable C<$sm>) is all right when packing, but this
+cannot be unpacked naively:
+
+ # pack a message
+ my $msg = pack( 'Z*Z*CA*C', $src, $dst, length( $sm ), $sm, $prio );
+
+ # unpack fails - $prio remains undefined!
+ ( $src, $dst, $len, $sm, $prio ) = unpack( 'Z*Z*CA*C', $msg );
+
+The pack code C<A*> gobbles up all remaining bytes, and C<$prio> remains
+undefined! Before we let disappointment dampen the morale: Perl's got
+the trump card to make this trick too, just a little further up the sleeve.
+Watch this:
+
+ # pack a message: ASCIIZ, ASCIIZ, length/string, byte
+ my $msg = pack( 'Z* Z* C/A* C', $src, $dst, $sm, $prio );
+
+ # unpack
+ ( $src, $dst, $sm, $prio ) = unpack( 'Z* Z* C/A* C', $msg );
+
+Combining two pack codes with a slash (C</>) associates them with a single
+value from the argument list. In C<pack>, the length of the argument is
+taken and packed according to the first code while the argument itself
+is added after being converted with the template code after the slash.
+This saves us the trouble of inserting the C<length> call, but it is
+in C<unpack> where we really score: The value of the length byte marks the
+end of the string to be taken from the buffer. Since this combination
+doesn't make sense except when the second pack code isn't C<a*>, C<A*>
+or C<Z*>, Perl won't let you.
+
+The pack code preceding C</> may be anything that's fit to represent a
+number: All the numeric binary pack codes, and even text codes such as
+C<A4> or C<Z*>:
+
+ # pack/unpack a string preceded by its length in ASCII
+ my $buf = pack( 'A4/A*', "Humpty-Dumpty" );
+ # unpack $buf: '13 Humpty-Dumpty'
+ my $txt = unpack( 'A4/A*', $buf );
+
+C</> is not implemented in Perls before 5.6, so if your code is required to
+work on older Perls you'll need to C<unpack( 'Z* Z* C')> to get the length,
+then use it to make a new unpack string. For example
+
+ # pack a message: ASCIIZ, ASCIIZ, length, string, byte (5.005 compatible)
+ my $msg = pack( 'Z* Z* C A* C', $src, $dst, length $sm, $sm, $prio );
+
+ # unpack
+ ( undef, undef, $len) = unpack( 'Z* Z* C', $msg );
+ ($src, $dst, $sm, $prio) = unpack ( "Z* Z* x A$len C", $msg );
+
+But that second C<unpack> is rushing ahead. It isn't using a simple literal
+string for the template. So maybe we should introduce...
+
+=head2 Dynamic Templates
+
+So far, we've seen literals used as templates. If the list of pack
+items doesn't have fixed length, an expression constructing the
+template is required (whenever, for some reason, C<()*> cannot be used).
+Here's an example: To store named string values in a way that can be
+conveniently parsed by a C program, we create a sequence of names and
+null terminated ASCII strings, with C<=> between the name and the value,
+followed by an additional delimiting null byte. Here's how:
+
+ my $env = pack( '(A*A*Z*)' . keys( %Env ) . 'C',
+ map( { ( $_, '=', $Env{$_} ) } keys( %Env ) ), 0 );
+
+Let's examine the cogs of this byte mill, one by one. There's the C<map>
+call, creating the items we intend to stuff into the C<$env> buffer:
+to each key (in C<$_>) it adds the C<=> separator and the hash entry value.
+Each triplet is packed with the template code sequence C<A*A*Z*> that
+is repeated according to the number of keys. (Yes, that's what the C<keys>
+function returns in scalar context.) To get the very last null byte,
+we add a C<0> at the end of the C<pack> list, to be packed with C<C>.
+(Attentive readers may have noticed that we could have omitted the 0.)
+
+For the reverse operation, we'll have to determine the number of items
+in the buffer before we can let C<unpack> rip it apart:
+
+ my $n = $env =~ tr/\0// - 1;
+ my %env = map( split( /=/, $_ ), unpack( "(Z*)$n", $env ) );
+
+The C<tr> counts the null bytes. The C<unpack> call returns a list of
+name-value pairs each of which is taken apart in the C<map> block.
+
+
+=head2 Counting Repetitions
+
+Rather than storing a sentinel at the end of a data item (or a list of items),
+we could precede the data with a count. Again, we pack keys and values of
+a hash, preceding each with an unsigned short length count, and up front
+we store the number of pairs:
+
+ my $env = pack( 'S(S/A* S/A*)*', scalar keys( %Env ), %Env );
+
+This simplifies the reverse operation as the number of repetitions can be
+unpacked with the C</> code:
+
+ my %env = unpack( 'S/(S/A* S/A*)', $env );
+
+Note that this is one of the rare cases where you cannot use the same
+template for C<pack> and C<unpack> because C<pack> can't determine
+a repeat count for a C<()>-group.
+
+
+=head2 Intel HEX
+
+Intel HEX is a file format for representing binary data, mostly for
+programming various chips, as a text file. (See
+L<http://en.wikipedia.org/wiki/.hex> for a detailed description, and
+L<http://en.wikipedia.org/wiki/SREC_(file_format)> for the Motorola
+S-record format, which can be unravelled using the same technique.)
+Each line begins with a colon (':') and is followed by a sequence of
+hexadecimal characters, specifying a byte count I<n> (8 bit),
+an address (16 bit, big endian), a record type (8 bit), I<n> data bytes
+and a checksum (8 bit) computed as the least significant byte of the two's
+complement sum of the preceding bytes. Example: C<:0300300002337A1E>.
+
+The first step of processing such a line is the conversion, to binary,
+of the hexadecimal data, to obtain the four fields, while checking the
+checksum. No surprise here: we'll start with a simple C<pack> call to
+convert everything to binary:
+
+ my $binrec = pack( 'H*', substr( $hexrec, 1 ) );
+
+The resulting byte sequence is most convenient for checking the checksum.
+Don't slow your program down with a for loop adding the C<ord> values
+of this string's bytes - the C<unpack> code C<%> is the thing to use
+for computing the 8-bit sum of all bytes, which must be equal to zero:
+
+ die unless unpack( "%8C*", $binrec ) == 0;
+
+Finally, let's get those four fields. By now, you shouldn't have any
+problems with the first three fields - but how can we use the byte count
+of the data in the first field as a length for the data field? Here
+the codes C<x> and C<X> come to the rescue, as they permit jumping
+back and forth in the string to unpack.
+
+ my( $addr, $type, $data ) = unpack( "x n C X4 C x3 /a", $bin );
+
+Code C<x> skips a byte, since we don't need the count yet. Code C<n> takes
+care of the 16-bit big-endian integer address, and C<C> unpacks the
+record type. Being at offset 4, where the data begins, we need the count.
+C<X4> brings us back to square one, which is the byte at offset 0.
+Now we pick up the count, and zoom forth to offset 4, where we are
+now fully furnished to extract the exact number of data bytes, leaving
+the trailing checksum byte alone.
+
+
+
+=head1 Packing and Unpacking C Structures
+
+In previous sections we have seen how to pack numbers and character
+strings. If it were not for a couple of snags we could conclude this
+section right away with the terse remark that C structures don't
+contain anything else, and therefore you already know all there is to it.
+Sorry, no: read on, please.
+
+If you have to deal with a lot of C structures, and don't want to
+hack all your template strings manually, you'll probably want to have
+a look at the CPAN module C<Convert::Binary::C>. Not only can it parse
+your C source directly, but it also has built-in support for all the
+odds and ends described further on in this section.
+
+=head2 The Alignment Pit
+
+In the consideration of speed against memory requirements the balance
+has been tilted in favor of faster execution. This has influenced the
+way C compilers allocate memory for structures: On architectures
+where a 16-bit or 32-bit operand can be moved faster between places in
+memory, or to or from a CPU register, if it is aligned at an even or
+multiple-of-four or even at a multiple-of eight address, a C compiler
+will give you this speed benefit by stuffing extra bytes into structures.
+If you don't cross the C shoreline this is not likely to cause you any
+grief (although you should care when you design large data structures,
+or you want your code to be portable between architectures (you do want
+that, don't you?)).
+
+To see how this affects C<pack> and C<unpack>, we'll compare these two
+C structures:
+
+ typedef struct {
+ char c1;
+ short s;
+ char c2;
+ long l;
+ } gappy_t;
+
+ typedef struct {
+ long l;
+ short s;
+ char c1;
+ char c2;
+ } dense_t;
+
+Typically, a C compiler allocates 12 bytes to a C<gappy_t> variable, but
+requires only 8 bytes for a C<dense_t>. After investigating this further,
+we can draw memory maps, showing where the extra 4 bytes are hidden:
+
+ 0 +4 +8 +12
+ +--+--+--+--+--+--+--+--+--+--+--+--+
+ |c1|xx| s |c2|xx|xx|xx| l | xx = fill byte
+ +--+--+--+--+--+--+--+--+--+--+--+--+
+ gappy_t
+
+ 0 +4 +8
+ +--+--+--+--+--+--+--+--+
+ | l | h |c1|c2|
+ +--+--+--+--+--+--+--+--+
+ dense_t
+
+And that's where the first quirk strikes: C<pack> and C<unpack>
+templates have to be stuffed with C<x> codes to get those extra fill bytes.
+
+The natural question: "Why can't Perl compensate for the gaps?" warrants
+an answer. One good reason is that C compilers might provide (non-ANSI)
+extensions permitting all sorts of fancy control over the way structures
+are aligned, even at the level of an individual structure field. And, if
+this were not enough, there is an insidious thing called C<union> where
+the amount of fill bytes cannot be derived from the alignment of the next
+item alone.
+
+OK, so let's bite the bullet. Here's one way to get the alignment right
+by inserting template codes C<x>, which don't take a corresponding item
+from the list:
+
+ my $gappy = pack( 'cxs cxxx l!', $c1, $s, $c2, $l );
+
+Note the C<!> after C<l>: We want to make sure that we pack a long
+integer as it is compiled by our C compiler. And even now, it will only
+work for the platforms where the compiler aligns things as above.
+And somebody somewhere has a platform where it doesn't.
+[Probably a Cray, where C<short>s, C<int>s and C<long>s are all 8 bytes. :-)]
+
+Counting bytes and watching alignments in lengthy structures is bound to
+be a drag. Isn't there a way we can create the template with a simple
+program? Here's a C program that does the trick:
+
+ #include <stdio.h>
+ #include <stddef.h>
+
+ typedef struct {
+ char fc1;
+ short fs;
+ char fc2;
+ long fl;
+ } gappy_t;
+
+ #define Pt(struct,field,tchar) \
+ printf( "@%d%s ", offsetof(struct,field), # tchar );
+
+ int main() {
+ Pt( gappy_t, fc1, c );
+ Pt( gappy_t, fs, s! );
+ Pt( gappy_t, fc2, c );
+ Pt( gappy_t, fl, l! );
+ printf( "\n" );
+ }
+
+The output line can be used as a template in a C<pack> or C<unpack> call:
+
+ my $gappy = pack( '@0c @2s! @4c @8l!', $c1, $s, $c2, $l );
+
+Gee, yet another template code - as if we hadn't plenty. But
+C<@> saves our day by enabling us to specify the offset from the beginning
+of the pack buffer to the next item: This is just the value
+the C<offsetof> macro (defined in C<E<lt>stddef.hE<gt>>) returns when
+given a C<struct> type and one of its field names ("member-designator" in
+C standardese).
+
+Neither using offsets nor adding C<x>'s to bridge the gaps is satisfactory.
+(Just imagine what happens if the structure changes.) What we really need
+is a way of saying "skip as many bytes as required to the next multiple of N".
+In fluent Templatese, you say this with C<x!N> where N is replaced by the
+appropriate value. Here's the next version of our struct packaging:
+
+ my $gappy = pack( 'c x!2 s c x!4 l!', $c1, $s, $c2, $l );
+
+That's certainly better, but we still have to know how long all the
+integers are, and portability is far away. Rather than C<2>,
+for instance, we want to say "however long a short is". But this can be
+done by enclosing the appropriate pack code in brackets: C<[s]>. So, here's
+the very best we can do:
+
+ my $gappy = pack( 'c x![s] s c x![l!] l!', $c1, $s, $c2, $l );
+
+
+=head2 Dealing with Endian-ness
+
+Now, imagine that we want to pack the data for a machine with a
+different byte-order. First, we'll have to figure out how big the data
+types on the target machine really are. Let's assume that the longs are
+32 bits wide and the shorts are 16 bits wide. You can then rewrite the
+template as:
+
+ my $gappy = pack( 'c x![s] s c x![l] l', $c1, $s, $c2, $l );
+
+If the target machine is little-endian, we could write:
+
+ my $gappy = pack( 'c x![s] s< c x![l] l<', $c1, $s, $c2, $l );
+
+This forces the short and the long members to be little-endian, and is
+just fine if you don't have too many struct members. But we could also
+use the byte-order modifier on a group and write the following:
+
+ my $gappy = pack( '( c x![s] s c x![l] l )<', $c1, $s, $c2, $l );
+
+This is not as short as before, but it makes it more obvious that we
+intend to have little-endian byte-order for a whole group, not only
+for individual template codes. It can also be more readable and easier
+to maintain.
+
+
+=head2 Alignment, Take 2
+
+I'm afraid that we're not quite through with the alignment catch yet. The
+hydra raises another ugly head when you pack arrays of structures:
+
+ typedef struct {
+ short count;
+ char glyph;
+ } cell_t;
+
+ typedef cell_t buffer_t[BUFLEN];
+
+Where's the catch? Padding is neither required before the first field C<count>,
+nor between this and the next field C<glyph>, so why can't we simply pack
+like this:
+
+ # something goes wrong here:
+ pack( 's!a' x @buffer,
+ map{ ( $_->{count}, $_->{glyph} ) } @buffer );
+
+This packs C<3*@buffer> bytes, but it turns out that the size of
+C<buffer_t> is four times C<BUFLEN>! The moral of the story is that
+the required alignment of a structure or array is propagated to the
+next higher level where we have to consider padding I<at the end>
+of each component as well. Thus the correct template is:
+
+ pack( 's!ax' x @buffer,
+ map{ ( $_->{count}, $_->{glyph} ) } @buffer );
+
+=head2 Alignment, Take 3
+
+And even if you take all the above into account, ANSI still lets this:
+
+ typedef struct {
+ char foo[2];
+ } foo_t;
+
+vary in size. The alignment constraint of the structure can be greater than
+any of its elements. [And if you think that this doesn't affect anything
+common, dismember the next cellphone that you see. Many have ARM cores, and
+the ARM structure rules make C<sizeof (foo_t)> == 4]
+
+=head2 Pointers for How to Use Them
+
+The title of this section indicates the second problem you may run into
+sooner or later when you pack C structures. If the function you intend
+to call expects a, say, C<void *> value, you I<cannot> simply take
+a reference to a Perl variable. (Although that value certainly is a
+memory address, it's not the address where the variable's contents are
+stored.)
+
+Template code C<P> promises to pack a "pointer to a fixed length string".
+Isn't this what we want? Let's try:
+
+ # allocate some storage and pack a pointer to it
+ my $memory = "\x00" x $size;
+ my $memptr = pack( 'P', $memory );
+
+But wait: doesn't C<pack> just return a sequence of bytes? How can we pass this
+string of bytes to some C code expecting a pointer which is, after all,
+nothing but a number? The answer is simple: We have to obtain the numeric
+address from the bytes returned by C<pack>.
+
+ my $ptr = unpack( 'L!', $memptr );
+
+Obviously this assumes that it is possible to typecast a pointer
+to an unsigned long and vice versa, which frequently works but should not
+be taken as a universal law. - Now that we have this pointer the next question
+is: How can we put it to good use? We need a call to some C function
+where a pointer is expected. The read(2) system call comes to mind:
+
+ ssize_t read(int fd, void *buf, size_t count);
+
+After reading L<perlfunc> explaining how to use C<syscall> we can write
+this Perl function copying a file to standard output:
+
+ require 'syscall.ph';
+ sub cat($){
+ my $path = shift();
+ my $size = -s $path;
+ my $memory = "\x00" x $size; # allocate some memory
+ my $ptr = unpack( 'L', pack( 'P', $memory ) );
+ open( F, $path ) || die( "$path: cannot open ($!)\n" );
+ my $fd = fileno(F);
+ my $res = syscall( &SYS_read, fileno(F), $ptr, $size );
+ print $memory;
+ close( F );
+ }
+
+This is neither a specimen of simplicity nor a paragon of portability but
+it illustrates the point: We are able to sneak behind the scenes and
+access Perl's otherwise well-guarded memory! (Important note: Perl's
+C<syscall> does I<not> require you to construct pointers in this roundabout
+way. You simply pass a string variable, and Perl forwards the address.)
+
+How does C<unpack> with C<P> work? Imagine some pointer in the buffer
+about to be unpacked: If it isn't the null pointer (which will smartly
+produce the C<undef> value) we have a start address - but then what?
+Perl has no way of knowing how long this "fixed length string" is, so
+it's up to you to specify the actual size as an explicit length after C<P>.
+
+ my $mem = "abcdefghijklmn";
+ print unpack( 'P5', pack( 'P', $mem ) ); # prints "abcde"
+
+As a consequence, C<pack> ignores any number or C<*> after C<P>.
+
+
+Now that we have seen C<P> at work, we might as well give C<p> a whirl.
+Why do we need a second template code for packing pointers at all? The
+answer lies behind the simple fact that an C<unpack> with C<p> promises
+a null-terminated string starting at the address taken from the buffer,
+and that implies a length for the data item to be returned:
+
+ my $buf = pack( 'p', "abc\x00efhijklmn" );
+ print unpack( 'p', $buf ); # prints "abc"
+
+
+
+Albeit this is apt to be confusing: As a consequence of the length being
+implied by the string's length, a number after pack code C<p> is a repeat
+count, not a length as after C<P>.
+
+
+Using C<pack(..., $x)> with C<P> or C<p> to get the address where C<$x> is
+actually stored must be used with circumspection. Perl's internal machinery
+considers the relation between a variable and that address as its very own
+private matter and doesn't really care that we have obtained a copy. Therefore:
+
+=over 4
+
+=item *
+
+Do not use C<pack> with C<p> or C<P> to obtain the address of variable
+that's bound to go out of scope (and thereby freeing its memory) before you
+are done with using the memory at that address.
+
+=item *
+
+Be very careful with Perl operations that change the value of the
+variable. Appending something to the variable, for instance, might require
+reallocation of its storage, leaving you with a pointer into no-man's land.
+
+=item *
+
+Don't think that you can get the address of a Perl variable
+when it is stored as an integer or double number! C<pack('P', $x)> will
+force the variable's internal representation to string, just as if you
+had written something like C<$x .= ''>.
+
+=back
+
+It's safe, however, to P- or p-pack a string literal, because Perl simply
+allocates an anonymous variable.
+
+
+
+=head1 Pack Recipes
+
+Here are a collection of (possibly) useful canned recipes for C<pack>
+and C<unpack>:
+
+ # Convert IP address for socket functions
+ pack( "C4", split /\./, "123.4.5.6" );
+
+ # Count the bits in a chunk of memory (e.g. a select vector)
+ unpack( '%32b*', $mask );
+
+ # Determine the endianness of your system
+ $is_little_endian = unpack( 'c', pack( 's', 1 ) );
+ $is_big_endian = unpack( 'xc', pack( 's', 1 ) );
+
+ # Determine the number of bits in a native integer
+ $bits = unpack( '%32I!', ~0 );
+
+ # Prepare argument for the nanosleep system call
+ my $timespec = pack( 'L!L!', $secs, $nanosecs );
+
+For a simple memory dump we unpack some bytes into just as
+many pairs of hex digits, and use C<map> to handle the traditional
+spacing - 16 bytes to a line:
+
+ my $i;
+ print map( ++$i % 16 ? "$_ " : "$_\n",
+ unpack( 'H2' x length( $mem ), $mem ) ),
+ length( $mem ) % 16 ? "\n" : '';
+
+
+=head1 Funnies Section
+
+ # Pulling digits out of nowhere...
+ print unpack( 'C', pack( 'x' ) ),
+ unpack( '%B*', pack( 'A' ) ),
+ unpack( 'H', pack( 'A' ) ),
+ unpack( 'A', unpack( 'C', pack( 'A' ) ) ), "\n";
+
+ # One for the road ;-)
+ my $advice = pack( 'all u can in a van' );
+
+
+=head1 Authors
+
+Simon Cozens and Wolfgang Laun.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlperf.pod b/Master/tlpkg/tlperl/lib/pods/perlperf.pod
new file mode 100644
index 00000000000..a934271088b
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlperf.pod
@@ -0,0 +1,1179 @@
+=head1 NAME
+
+perlperf - Perl Performance and Optimization Techniques
+
+=head1 DESCRIPTION
+
+This is an introduction to the use of performance and optimization techniques
+which can be used with particular reference to perl programs. While many perl
+developers have come from other languages, and can use their prior knowledge
+where appropriate, there are many other people who might benefit from a few
+perl specific pointers. If you want the condensed version, perhaps the best
+advice comes from the renowned Japanese Samurai, Miyamoto Musashi, who said:
+
+ "Do Not Engage in Useless Activity"
+
+in 1645.
+
+=head1 OVERVIEW
+
+Perhaps the most common mistake programmers make is to attempt to optimize
+their code before a program actually does anything useful - this is a bad idea.
+There's no point in having an extremely fast program that doesn't work. The
+first job is to get a program to I<correctly> do something B<useful>, (not to
+mention ensuring the test suite is fully functional), and only then to consider
+optimizing it. Having decided to optimize existing working code, there are
+several simple but essential steps to consider which are intrinsic to any
+optimization process.
+
+=head2 ONE STEP SIDEWAYS
+
+Firstly, you need to establish a baseline time for the existing code, which
+timing needs to be reliable and repeatable. You'll probably want to use the
+C<Benchmark> or C<Devel::DProf> modules, or something similar, for this step,
+or perhaps the Unix system C<time> utility, whichever is appropriate. See the
+base of this document for a longer list of benchmarking and profiling modules,
+and recommended further reading.
+
+=head2 ONE STEP FORWARD
+
+Next, having examined the program for I<hot spots>, (places where the code
+seems to run slowly), change the code with the intention of making it run
+faster. Using version control software, like C<subversion>, will ensure no
+changes are irreversible. It's too easy to fiddle here and fiddle there -
+don't change too much at any one time or you might not discover which piece of
+code B<really> was the slow bit.
+
+=head2 ANOTHER STEP SIDEWAYS
+
+It's not enough to say: "that will make it run faster", you have to check it.
+Rerun the code under control of the benchmarking or profiling modules, from the
+first step above, and check that the new code executed the B<same task> in
+I<less time>. Save your work and repeat...
+
+=head1 GENERAL GUIDELINES
+
+The critical thing when considering performance is to remember there is no such
+thing as a C<Golden Bullet>, which is why there are no rules, only guidelines.
+
+It is clear that inline code is going to be faster than subroutine or method
+calls, because there is less overhead, but this approach has the disadvantage
+of being less maintainable and comes at the cost of greater memory usage -
+there is no such thing as a free lunch. If you are searching for an element in
+a list, it can be more efficient to store the data in a hash structure, and
+then simply look to see whether the key is defined, rather than to loop through
+the entire array using grep() for instance. substr() may be (a lot) faster
+than grep() but not as flexible, so you have another trade-off to access. Your
+code may contain a line which takes 0.01 of a second to execute which if you
+call it 1,000 times, quite likely in a program parsing even medium sized files
+for instance, you already have a 10 second delay, in just one single code
+location, and if you call that line 100,000 times, your entire program will
+slow down to an unbearable crawl.
+
+Using a subroutine as part of your sort is a powerful way to get exactly what
+you want, but will usually be slower than the built-in I<alphabetic> C<cmp> and
+I<numeric> C<E<lt>=E<gt>> sort operators. It is possible to make multiple
+passes over your data, building indices to make the upcoming sort more
+efficient, and to use what is known as the C<OM> (Orcish Maneuver) to cache the
+sort keys in advance. The cache lookup, while a good idea, can itself be a
+source of slowdown by enforcing a double pass over the data - once to setup the
+cache, and once to sort the data. Using C<pack()> to extract the required sort
+key into a consistent string can be an efficient way to build a single string
+to compare, instead of using multiple sort keys, which makes it possible to use
+the standard, written in C<c> and fast, perl C<sort()> function on the output,
+and is the basis of the C<GRT> (Guttman Rossler Transform). Some string
+combinations can slow the C<GRT> down, by just being too plain complex for it's
+own good.
+
+For applications using database backends, the standard C<DBIx> namespace has
+tries to help with keeping things nippy, not least because it tries to I<not>
+query the database until the latest possible moment, but always read the docs
+which come with your choice of libraries. Among the many issues facing
+developers dealing with databases should remain aware of is to always use
+C<SQL> placeholders and to consider pre-fetching data sets when this might
+prove advantageous. Splitting up a large file by assigning multiple processes
+to parsing a single file, using say C<POE>, C<threads> or C<fork> can also be a
+useful way of optimizing your usage of the available C<CPU> resources, though
+this technique is fraught with concurrency issues and demands high attention to
+detail.
+
+Every case has a specific application and one or more exceptions, and there is
+no replacement for running a few tests and finding out which method works best
+for your particular environment, this is why writing optimal code is not an
+exact science, and why we love using Perl so much - TMTOWTDI.
+
+=head1 BENCHMARKS
+
+Here are a few examples to demonstrate usage of Perl's benchmarking tools.
+
+=head2 Assigning and Dereferencing Variables.
+
+I'm sure most of us have seen code which looks like, (or worse than), this:
+
+ if ( $obj->{_ref}->{_myscore} >= $obj->{_ref}->{_yourscore} ) {
+ ...
+
+This sort of code can be a real eyesore to read, as well as being very
+sensitive to typos, and it's much clearer to dereference the variable
+explicitly. We're side-stepping the issue of working with object-oriented
+programming techniques to encapsulate variable access via methods, only
+accessible through an object. Here we're just discussing the technical
+implementation of choice, and whether this has an effect on performance. We
+can see whether this dereferencing operation, has any overhead by putting
+comparative code in a file and running a C<Benchmark> test.
+
+# dereference
+
+ #!/usr/bin/perl
+
+ use strict;
+ use warnings;
+
+ use Benchmark;
+
+ my $ref = {
+ 'ref' => {
+ _myscore => '100 + 1',
+ _yourscore => '102 - 1',
+ },
+ };
+
+ timethese(1000000, {
+ 'direct' => sub {
+ my $x = $ref->{ref}->{_myscore} . $ref->{ref}->{_yourscore} ;
+ },
+ 'dereference' => sub {
+ my $ref = $ref->{ref};
+ my $myscore = $ref->{_myscore};
+ my $yourscore = $ref->{_yourscore};
+ my $x = $myscore . $yourscore;
+ },
+ });
+
+It's essential to run any timing measurements a sufficient number of times so
+the numbers settle on a numerical average, otherwise each run will naturally
+fluctuate due to variations in the environment, to reduce the effect of
+contention for C<CPU> resources and network bandwidth for instance. Running
+the above code for one million iterations, we can take a look at the report
+output by the C<Benchmark> module, to see which approach is the most effective.
+
+ $> perl dereference
+
+ Benchmark: timing 1000000 iterations of dereference, direct...
+ dereference: 2 wallclock secs ( 1.59 usr + 0.00 sys = 1.59 CPU) @ 628930.82/s (n=1000000)
+ direct: 1 wallclock secs ( 1.20 usr + 0.00 sys = 1.20 CPU) @ 833333.33/s (n=1000000)
+
+The difference is clear to see and the dereferencing approach is slower. While
+it managed to execute an average of 628,930 times a second during our test, the
+direct approach managed to run an additional 204,403 times, unfortunately.
+Unfortunately, because there are many examples of code written using the
+multiple layer direct variable access, and it's usually horrible. It is,
+however, minusculy faster. The question remains whether the minute gain is
+actually worth the eyestrain, or the loss of maintainability.
+
+=head2 Search and replace or tr
+
+If we have a string which needs to be modified, while a regex will almost
+always be much more flexible, C<tr>, an oft underused tool, can still be a
+useful. One scenario might be replace all vowels with another character. The
+regex solution might look like this:
+
+ $str =~ s/[aeiou]/x/g
+
+The C<tr> alternative might look like this:
+
+ $str =~ tr/aeiou/xxxxx/
+
+We can put that into a test file which we can run to check which approach is
+the fastest, using a global C<$STR> variable to assign to the C<my $str>
+variable so as to avoid perl trying to optimize any of the work away by
+noticing it's assigned only the once.
+
+# regex-transliterate
+
+ #!/usr/bin/perl
+
+ use strict;
+ use warnings;
+
+ use Benchmark;
+
+ my $STR = "$$-this and that";
+
+ timethese( 1000000, {
+ 'sr' => sub { my $str = $STR; $str =~ s/[aeiou]/x/g; return $str; },
+ 'tr' => sub { my $str = $STR; $str =~ tr/aeiou/xxxxx/; return $str; },
+ });
+
+Running the code gives us our results:
+
+ $> perl regex-transliterate
+
+ Benchmark: timing 1000000 iterations of sr, tr...
+ sr: 2 wallclock secs ( 1.19 usr + 0.00 sys = 1.19 CPU) @ 840336.13/s (n=1000000)
+ tr: 0 wallclock secs ( 0.49 usr + 0.00 sys = 0.49 CPU) @ 2040816.33/s (n=1000000)
+
+The C<tr> version is a clear winner. One solution is flexible, the other is
+fast - and it's appropriately the programmer's choice which to use.
+
+Check the C<Benchmark> docs for further useful techniques.
+
+=head1 PROFILING TOOLS
+
+A slightly larger piece of code will provide something on which a profiler can
+produce more extensive reporting statistics. This example uses the simplistic
+C<wordmatch> program which parses a given input file and spews out a short
+report on the contents.
+
+# wordmatch
+
+ #!/usr/bin/perl
+
+ use strict;
+ use warnings;
+
+ =head1 NAME
+
+ filewords - word analysis of input file
+
+ =head1 SYNOPSIS
+
+ filewords -f inputfilename [-d]
+
+ =head1 DESCRIPTION
+
+ This program parses the given filename, specified with C<-f>, and displays a
+ simple analysis of the words found therein. Use the C<-d> switch to enable
+ debugging messages.
+
+ =cut
+
+ use FileHandle;
+ use Getopt::Long;
+
+ my $debug = 0;
+ my $file = '';
+
+ my $result = GetOptions (
+ 'debug' => \$debug,
+ 'file=s' => \$file,
+ );
+ die("invalid args") unless $result;
+
+ unless ( -f $file ) {
+ die("Usage: $0 -f filename [-d]");
+ }
+ my $FH = FileHandle->new("< $file") or die("unable to open file($file): $!");
+
+ my $i_LINES = 0;
+ my $i_WORDS = 0;
+ my %count = ();
+
+ my @lines = <$FH>;
+ foreach my $line ( @lines ) {
+ $i_LINES++;
+ $line =~ s/\n//;
+ my @words = split(/ +/, $line);
+ my $i_words = scalar(@words);
+ $i_WORDS = $i_WORDS + $i_words;
+ debug("line: $i_LINES supplying $i_words words: @words");
+ my $i_word = 0;
+ foreach my $word ( @words ) {
+ $i_word++;
+ $count{$i_LINES}{spec} += matches($i_word, $word, '[^a-zA-Z0-9]');
+ $count{$i_LINES}{only} += matches($i_word, $word, '^[^a-zA-Z0-9]+$');
+ $count{$i_LINES}{cons} += matches($i_word, $word, '^[(?i:bcdfghjklmnpqrstvwxyz)]+$');
+ $count{$i_LINES}{vows} += matches($i_word, $word, '^[(?i:aeiou)]+$');
+ $count{$i_LINES}{caps} += matches($i_word, $word, '^[(A-Z)]+$');
+ }
+ }
+
+ print report( %count );
+
+ sub matches {
+ my $i_wd = shift;
+ my $word = shift;
+ my $regex = shift;
+ my $has = 0;
+
+ if ( $word =~ /($regex)/ ) {
+ $has++ if $1;
+ }
+
+ debug("word: $i_wd ".($has ? 'matches' : 'does not match')." chars: /$regex/");
+
+ return $has;
+ }
+
+ sub report {
+ my %report = @_;
+ my %rep;
+
+ foreach my $line ( keys %report ) {
+ foreach my $key ( keys %{ $report{$line} } ) {
+ $rep{$key} += $report{$line}{$key};
+ }
+ }
+
+ my $report = qq|
+ $0 report for $file:
+ lines in file: $i_LINES
+ words in file: $i_WORDS
+ words with special (non-word) characters: $i_spec
+ words with only special (non-word) characters: $i_only
+ words with only consonants: $i_cons
+ words with only capital letters: $i_caps
+ words with only vowels: $i_vows
+ |;
+
+ return $report;
+ }
+
+ sub debug {
+ my $message = shift;
+
+ if ( $debug ) {
+ print STDERR "DBG: $message\n";
+ }
+ }
+
+ exit 0;
+
+=head2 Devel::DProf
+
+This venerable module has been the de-facto standard for Perl code profiling
+for more than a decade, but has been replaced by a number of other modules
+which have brought us back to the 21st century. Although you're recommended to
+evaluate your tool from the several mentioned here and from the CPAN list at
+the base of this document, (and currently L<Devel::NYTProf> seems to be the
+weapon of choice - see below), we'll take a quick look at the output from
+L<Devel::DProf> first, to set a baseline for Perl profiling tools. Run the
+above program under the control of C<Devel::DProf> by using the C<-d> switch on
+the command-line.
+
+ $> perl -d:DProf wordmatch -f perl5db.pl
+
+ <...multiple lines snipped...>
+
+ wordmatch report for perl5db.pl:
+ lines in file: 9428
+ words in file: 50243
+ words with special (non-word) characters: 20480
+ words with only special (non-word) characters: 7790
+ words with only consonants: 4801
+ words with only capital letters: 1316
+ words with only vowels: 1701
+
+C<Devel::DProf> produces a special file, called F<tmon.out> by default, and
+this file is read by the C<dprofpp> program, which is already installed as part
+of the C<Devel::DProf> distribution. If you call C<dprofpp> with no options,
+it will read the F<tmon.out> file in the current directory and produce a human
+readable statistics report of the run of your program. Note that this may take
+a little time.
+
+ $> dprofpp
+
+ Total Elapsed Time = 2.951677 Seconds
+ User+System Time = 2.871677 Seconds
+ Exclusive Times
+ %Time ExclSec CumulS #Calls sec/call Csec/c Name
+ 102. 2.945 3.003 251215 0.0000 0.0000 main::matches
+ 2.40 0.069 0.069 260643 0.0000 0.0000 main::debug
+ 1.74 0.050 0.050 1 0.0500 0.0500 main::report
+ 1.04 0.030 0.049 4 0.0075 0.0123 main::BEGIN
+ 0.35 0.010 0.010 3 0.0033 0.0033 Exporter::as_heavy
+ 0.35 0.010 0.010 7 0.0014 0.0014 IO::File::BEGIN
+ 0.00 - -0.000 1 - - Getopt::Long::FindOption
+ 0.00 - -0.000 1 - - Symbol::BEGIN
+ 0.00 - -0.000 1 - - Fcntl::BEGIN
+ 0.00 - -0.000 1 - - Fcntl::bootstrap
+ 0.00 - -0.000 1 - - warnings::BEGIN
+ 0.00 - -0.000 1 - - IO::bootstrap
+ 0.00 - -0.000 1 - - Getopt::Long::ConfigDefaults
+ 0.00 - -0.000 1 - - Getopt::Long::Configure
+ 0.00 - -0.000 1 - - Symbol::gensym
+
+C<dprofpp> will produce some quite detailed reporting on the activity of the
+C<wordmatch> program. The wallclock, user and system, times are at the top of
+the analysis, and after this are the main columns defining which define the
+report. Check the C<dprofpp> docs for details of the many options it supports.
+
+See also C<Apache::DProf> which hooks C<Devel::DProf> into C<mod_perl>.
+
+=head2 Devel::Profiler
+
+Let's take a look at the same program using a different profiler:
+C<Devel::Profiler>, a drop-in Perl-only replacement for C<Devel::DProf>. The
+usage is very slightly different in that instead of using the special C<-d:>
+flag, you pull C<Devel::Profiler> in directly as a module using C<-M>.
+
+ $> perl -MDevel::Profiler wordmatch -f perl5db.pl
+
+ <...multiple lines snipped...>
+
+ wordmatch report for perl5db.pl:
+ lines in file: 9428
+ words in file: 50243
+ words with special (non-word) characters: 20480
+ words with only special (non-word) characters: 7790
+ words with only consonants: 4801
+ words with only capital letters: 1316
+ words with only vowels: 1701
+
+
+C<Devel::Profiler> generates a tmon.out file which is compatible with the
+C<dprofpp> program, thus saving the construction of a dedicated statistics
+reader program. C<dprofpp> usage is therefore identical to the above example.
+
+ $> dprofpp
+
+ Total Elapsed Time = 20.984 Seconds
+ User+System Time = 19.981 Seconds
+ Exclusive Times
+ %Time ExclSec CumulS #Calls sec/call Csec/c Name
+ 49.0 9.792 14.509 251215 0.0000 0.0001 main::matches
+ 24.4 4.887 4.887 260643 0.0000 0.0000 main::debug
+ 0.25 0.049 0.049 1 0.0490 0.0490 main::report
+ 0.00 0.000 0.000 1 0.0000 0.0000 Getopt::Long::GetOptions
+ 0.00 0.000 0.000 2 0.0000 0.0000 Getopt::Long::ParseOptionSpec
+ 0.00 0.000 0.000 1 0.0000 0.0000 Getopt::Long::FindOption
+ 0.00 0.000 0.000 1 0.0000 0.0000 IO::File::new
+ 0.00 0.000 0.000 1 0.0000 0.0000 IO::Handle::new
+ 0.00 0.000 0.000 1 0.0000 0.0000 Symbol::gensym
+ 0.00 0.000 0.000 1 0.0000 0.0000 IO::File::open
+
+Interestingly we get slightly different results, which is mostly because the
+algorithm which generates the report is different, even though the output file
+format was allegedly identical. The elapsed, user and system times are clearly
+showing the time it took for C<Devel::Profiler> to execute its own run, but
+the column listings feel more accurate somehow than the ones we had earlier
+from C<Devel::DProf>. The 102% figure has disappeared, for example. This is
+where we have to use the tools at our disposal, and recognise their pros and
+cons, before using them. Interestingly, the numbers of calls for each
+subroutine are identical in the two reports, it's the percentages which differ.
+As the author of C<Devel::Proviler> writes:
+
+ ...running HTML::Template's test suite under Devel::DProf shows output()
+ taking NO time but Devel::Profiler shows around 10% of the time is in output().
+ I don't know which to trust but my gut tells me something is wrong with
+ Devel::DProf. HTML::Template::output() is a big routine that's called for
+ every test. Either way, something needs fixing.
+
+YMMV.
+
+See also C<Devel::Apache::Profiler> which hooks C<Devel::Profiler> into C<mod_perl>.
+
+=head2 Devel::SmallProf
+
+The C<Devel::SmallProf> profiler examines the runtime of your Perl program and
+produces a line-by-line listing to show how many times each line was called,
+and how long each line took to execute. It is called by supplying the familiar
+C<-d> flag to Perl at runtime.
+
+ $> perl -d:SmallProf wordmatch -f perl5db.pl
+
+ <...multiple lines snipped...>
+
+ wordmatch report for perl5db.pl:
+ lines in file: 9428
+ words in file: 50243
+ words with special (non-word) characters: 20480
+ words with only special (non-word) characters: 7790
+ words with only consonants: 4801
+ words with only capital letters: 1316
+ words with only vowels: 1701
+
+C<Devel::SmallProf> writes it's output into a file called F<smallprof.out>, by
+default. The format of the file looks like this:
+
+ <num> <time> <ctime> <line>:<text>
+
+When the program has terminated, the output may be examined and sorted using
+any standard text filtering utilities. Something like the following may be
+sufficient:
+
+ $> cat smallprof.out | grep \d*: | sort -k3 | tac | head -n20
+
+ 251215 1.65674 7.68000 75: if ( $word =~ /($regex)/ ) {
+ 251215 0.03264 4.40000 79: debug("word: $i_wd ".($has ? 'matches' :
+ 251215 0.02693 4.10000 81: return $has;
+ 260643 0.02841 4.07000 128: if ( $debug ) {
+ 260643 0.02601 4.04000 126: my $message = shift;
+ 251215 0.02641 3.91000 73: my $has = 0;
+ 251215 0.03311 3.71000 70: my $i_wd = shift;
+ 251215 0.02699 3.69000 72: my $regex = shift;
+ 251215 0.02766 3.68000 71: my $word = shift;
+ 50243 0.59726 1.00000 59: $count{$i_LINES}{cons} =
+ 50243 0.48175 0.92000 61: $count{$i_LINES}{spec} =
+ 50243 0.00644 0.89000 56: my $i_cons = matches($i_word, $word,
+ 50243 0.48837 0.88000 63: $count{$i_LINES}{caps} =
+ 50243 0.00516 0.88000 58: my $i_caps = matches($i_word, $word, '^[(A-
+ 50243 0.00631 0.81000 54: my $i_spec = matches($i_word, $word, '[^a-
+ 50243 0.00496 0.80000 57: my $i_vows = matches($i_word, $word,
+ 50243 0.00688 0.80000 53: $i_word++;
+ 50243 0.48469 0.79000 62: $count{$i_LINES}{only} =
+ 50243 0.48928 0.77000 60: $count{$i_LINES}{vows} =
+ 50243 0.00683 0.75000 55: my $i_only = matches($i_word, $word, '^[^a-
+
+You can immediately see a slightly different focus to the subroutine profiling
+modules, and we start to see exactly which line of code is taking the most
+time. That regex line is looking a bit suspicious, for example. Remember that
+these tools are supposed to be used together, there is no single best way to
+profile your code, you need to use the best tools for the job.
+
+See also C<Apache::SmallProf> which hooks C<Devel::SmallProf> into C<mod_perl>.
+
+=head2 Devel::FastProf
+
+C<Devel::FastProf> is another Perl line profiler. This was written with a view
+to getting a faster line profiler, than is possible with for example
+C<Devel::SmallProf>, because it's written in C<C>. To use C<Devel::FastProf>,
+supply the C<-d> argument to Perl:
+
+ $> perl -d:FastProf wordmatch -f perl5db.pl
+
+ <...multiple lines snipped...>
+
+ wordmatch report for perl5db.pl:
+ lines in file: 9428
+ words in file: 50243
+ words with special (non-word) characters: 20480
+ words with only special (non-word) characters: 7790
+ words with only consonants: 4801
+ words with only capital letters: 1316
+ words with only vowels: 1701
+
+C<Devel::FastProf> writes statistics to the file F<fastprof.out> in the current
+directory. The output file, which can be specified, can be interpreted by using
+the C<fprofpp> command-line program.
+
+ $> fprofpp | head -n20
+
+ # fprofpp output format is:
+ # filename:line time count: source
+ wordmatch:75 3.93338 251215: if ( $word =~ /($regex)/ ) {
+ wordmatch:79 1.77774 251215: debug("word: $i_wd ".($has ? 'matches' : 'does not match')." chars: /$regex/");
+ wordmatch:81 1.47604 251215: return $has;
+ wordmatch:126 1.43441 260643: my $message = shift;
+ wordmatch:128 1.42156 260643: if ( $debug ) {
+ wordmatch:70 1.36824 251215: my $i_wd = shift;
+ wordmatch:71 1.36739 251215: my $word = shift;
+ wordmatch:72 1.35939 251215: my $regex = shift;
+
+Straightaway we can see that the number of times each line has been called is
+identical to the C<Devel::SmallProf> output, and the sequence is only very
+slightly different based on the ordering of the amount of time each line took
+to execute, C<if ( $debug ) { > and C<my $message = shift;>, for example. The
+differences in the actual times recorded might be in the algorithm used
+internally, or it could be due to system resource limitations or contention.
+
+See also the L<DBIx::Profiler> which will profile database queries running
+under the C<DBIx::*> namespace.
+
+=head2 Devel::NYTProf
+
+C<Devel::NYTProf> is the B<next generation> of Perl code profiler, fixing many
+shortcomings in other tools and implementing many cool features. First of all it
+can be used as either a I<line> profiler, a I<block> or a I<subroutine>
+profiler, all at once. It can also use sub-microsecond (100ns) resolution on
+systems which provide C<clock_gettime()>. It can be started and stopped even
+by the program being profiled. It's a one-line entry to profile C<mod_perl>
+applications. It's written in C<c> and is probably the fastest profiler
+available for Perl. The list of coolness just goes on. Enough of that, let's
+see how to it works - just use the familiar C<-d> switch to plug it in and run
+the code.
+
+ $> perl -d:NYTProf wordmatch -f perl5db.pl
+
+ wordmatch report for perl5db.pl:
+ lines in file: 9427
+ words in file: 50243
+ words with special (non-word) characters: 20480
+ words with only special (non-word) characters: 7790
+ words with only consonants: 4801
+ words with only capital letters: 1316
+ words with only vowels: 1701
+
+C<NYTProf> will generate a report database into the file F<nytprof.out> by
+default. Human readable reports can be generated from here by using the
+supplied C<nytprofhtml> (HTML output) and C<nytprofcsv> (CSV output) programs.
+We've used the Unix sytem C<html2text> utility to convert the
+F<nytprof/index.html> file for convenience here.
+
+ $> html2text nytprof/index.html
+
+ Performance Profile Index
+ For wordmatch
+ Run on Fri Sep 26 13:46:39 2008
+ Reported on Fri Sep 26 13:47:23 2008
+
+ Top 15 Subroutines -- ordered by exclusive time
+ |Calls |P |F |Inclusive|Exclusive|Subroutine |
+ | | | |Time |Time | |
+ |251215|5 |1 |13.09263 |10.47692 |main:: |matches |
+ |260642|2 |1 |2.71199 |2.71199 |main:: |debug |
+ |1 |1 |1 |0.21404 |0.21404 |main:: |report |
+ |2 |2 |2 |0.00511 |0.00511 |XSLoader:: |load (xsub) |
+ |14 |14|7 |0.00304 |0.00298 |Exporter:: |import |
+ |3 |1 |1 |0.00265 |0.00254 |Exporter:: |as_heavy |
+ |10 |10|4 |0.00140 |0.00140 |vars:: |import |
+ |13 |13|1 |0.00129 |0.00109 |constant:: |import |
+ |1 |1 |1 |0.00360 |0.00096 |FileHandle:: |import |
+ |3 |3 |3 |0.00086 |0.00074 |warnings::register::|import |
+ |9 |3 |1 |0.00036 |0.00036 |strict:: |bits |
+ |13 |13|13|0.00032 |0.00029 |strict:: |import |
+ |2 |2 |2 |0.00020 |0.00020 |warnings:: |import |
+ |2 |1 |1 |0.00020 |0.00020 |Getopt::Long:: |ParseOptionSpec|
+ |7 |7 |6 |0.00043 |0.00020 |strict:: |unimport |
+
+ For more information see the full list of 189 subroutines.
+
+The first part of the report already shows the critical information regarding
+which subroutines are using the most time. The next gives some statistics
+about the source files profiled.
+
+ Source Code Files -- ordered by exclusive time then name
+ |Stmts |Exclusive|Avg. |Reports |Source File |
+ | |Time | | | |
+ |2699761|15.66654 |6e-06 |line . block . sub|wordmatch |
+ |35 |0.02187 |0.00062|line . block . sub|IO/Handle.pm |
+ |274 |0.01525 |0.00006|line . block . sub|Getopt/Long.pm |
+ |20 |0.00585 |0.00029|line . block . sub|Fcntl.pm |
+ |128 |0.00340 |0.00003|line . block . sub|Exporter/Heavy.pm |
+ |42 |0.00332 |0.00008|line . block . sub|IO/File.pm |
+ |261 |0.00308 |0.00001|line . block . sub|Exporter.pm |
+ |323 |0.00248 |8e-06 |line . block . sub|constant.pm |
+ |12 |0.00246 |0.00021|line . block . sub|File/Spec/Unix.pm |
+ |191 |0.00240 |0.00001|line . block . sub|vars.pm |
+ |77 |0.00201 |0.00003|line . block . sub|FileHandle.pm |
+ |12 |0.00198 |0.00016|line . block . sub|Carp.pm |
+ |14 |0.00175 |0.00013|line . block . sub|Symbol.pm |
+ |15 |0.00130 |0.00009|line . block . sub|IO.pm |
+ |22 |0.00120 |0.00005|line . block . sub|IO/Seekable.pm |
+ |198 |0.00085 |4e-06 |line . block . sub|warnings/register.pm|
+ |114 |0.00080 |7e-06 |line . block . sub|strict.pm |
+ |47 |0.00068 |0.00001|line . block . sub|warnings.pm |
+ |27 |0.00054 |0.00002|line . block . sub|overload.pm |
+ |9 |0.00047 |0.00005|line . block . sub|SelectSaver.pm |
+ |13 |0.00045 |0.00003|line . block . sub|File/Spec.pm |
+ |2701595|15.73869 | |Total |
+ |128647 |0.74946 | |Average |
+ | |0.00201 |0.00003|Median |
+ | |0.00121 |0.00003|Deviation |
+
+ Report produced by the NYTProf 2.03 Perl profiler, developed by Tim Bunce and
+ Adam Kaplan.
+
+At this point, if you're using the I<html> report, you can click through the
+various links to bore down into each subroutine and each line of code. Because
+we're using the text reporting here, and there's a whole directory full of
+reports built for each source file, we'll just display a part of the
+corresponding F<wordmatch-line.html> file, sufficient to give an idea of the
+sort of output you can expect from this cool tool.
+
+ $> html2text nytprof/wordmatch-line.html
+
+ Performance Profile -- -block view-.-line view-.-sub view-
+ For wordmatch
+ Run on Fri Sep 26 13:46:39 2008
+ Reported on Fri Sep 26 13:47:22 2008
+
+ File wordmatch
+
+ Subroutines -- ordered by exclusive time
+ |Calls |P|F|Inclusive|Exclusive|Subroutine |
+ | | | |Time |Time | |
+ |251215|5|1|13.09263 |10.47692 |main::|matches|
+ |260642|2|1|2.71199 |2.71199 |main::|debug |
+ |1 |1|1|0.21404 |0.21404 |main::|report |
+ |0 |0|0|0 |0 |main::|BEGIN |
+
+
+ |Line|Stmts.|Exclusive|Avg. |Code |
+ | | |Time | | |
+ |1 | | | |#!/usr/bin/perl |
+ |2 | | | | |
+ | | | | |use strict; |
+ |3 |3 |0.00086 |0.00029|# spent 0.00003s making 1 calls to strict:: |
+ | | | | |import |
+ | | | | |use warnings; |
+ |4 |3 |0.01563 |0.00521|# spent 0.00012s making 1 calls to warnings:: |
+ | | | | |import |
+ |5 | | | | |
+ |6 | | | |=head1 NAME |
+ |7 | | | | |
+ |8 | | | |filewords - word analysis of input file |
+ <...snip...>
+ |62 |1 |0.00445 |0.00445|print report( %count ); |
+ | | | | |# spent 0.21404s making 1 calls to main::report|
+ |63 | | | | |
+ | | | | |# spent 23.56955s (10.47692+2.61571) within |
+ | | | | |main::matches which was called 251215 times, |
+ | | | | |avg 0.00005s/call: # 50243 times |
+ | | | | |(2.12134+0.51939s) at line 57 of wordmatch, avg|
+ | | | | |0.00005s/call # 50243 times (2.17735+0.54550s) |
+ |64 | | | |at line 56 of wordmatch, avg 0.00005s/call # |
+ | | | | |50243 times (2.10992+0.51797s) at line 58 of |
+ | | | | |wordmatch, avg 0.00005s/call # 50243 times |
+ | | | | |(2.12696+0.51598s) at line 55 of wordmatch, avg|
+ | | | | |0.00005s/call # 50243 times (1.94134+0.51687s) |
+ | | | | |at line 54 of wordmatch, avg 0.00005s/call |
+ | | | | |sub matches { |
+ <...snip...>
+ |102 | | | | |
+ | | | | |# spent 2.71199s within main::debug which was |
+ | | | | |called 260642 times, avg 0.00001s/call: # |
+ | | | | |251215 times (2.61571+0s) by main::matches at |
+ |103 | | | |line 74 of wordmatch, avg 0.00001s/call # 9427 |
+ | | | | |times (0.09628+0s) at line 50 of wordmatch, avg|
+ | | | | |0.00001s/call |
+ | | | | |sub debug { |
+ |104 |260642|0.58496 |2e-06 |my $message = shift; |
+ |105 | | | | |
+ |106 |260642|1.09917 |4e-06 |if ( $debug ) { |
+ |107 | | | |print STDERR "DBG: $message\n"; |
+ |108 | | | |} |
+ |109 | | | |} |
+ |110 | | | | |
+ |111 |1 |0.01501 |0.01501|exit 0; |
+ |112 | | | | |
+
+Oodles of very useful information in there - this seems to be the way forward.
+
+See also C<Devel::NYTProf::Apache> which hooks C<Devel::NYTProf> into C<mod_perl>.
+
+=head1 SORTING
+
+Perl modules are not the only tools a performance analyst has at their
+disposal, system tools like C<time> should not be overlooked as the next
+example shows, where we take a quick look at sorting. Many books, theses and
+articles, have been written about efficient sorting algorithms, and this is not
+the place to repeat such work, there's several good sorting modules which
+deserve taking a look at too: C<Sort::Maker>, C<Sort::Key> spring to mind.
+However, it's still possible to make some observations on certain Perl specific
+interpretations on issues relating to sorting data sets and give an example or
+two with regard to how sorting large data volumes can effect performance.
+Firstly, an often overlooked point when sorting large amounts of data, one can
+attempt to reduce the data set to be dealt with and in many cases C<grep()> can
+be quite useful as a simple filter:
+
+ @data = sort grep { /$filter/ } @incoming
+
+A command such as this can vastly reduce the volume of material to actually
+sort through in the first place, and should not be too lightly disregarded
+purely on the basis of its simplicity. The C<KISS> principle is too often
+overlooked - the next example uses the simple system C<time> utility to
+demonstrate. Let's take a look at an actual example of sorting the contents of
+a large file, an apache logfile would do. This one has over a quarter of a
+million lines, is 50M in size, and a snippet of it looks like this:
+
+# logfile
+
+ 188.209-65-87.adsl-dyn.isp.belgacom.be - - [08/Feb/2007:12:57:16 +0000] "GET /favicon.ico HTTP/1.1" 404 209 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ 188.209-65-87.adsl-dyn.isp.belgacom.be - - [08/Feb/2007:12:57:16 +0000] "GET /favicon.ico HTTP/1.1" 404 209 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ 151.56.71.198 - - [08/Feb/2007:12:57:41 +0000] "GET /suse-on-vaio.html HTTP/1.1" 200 2858 "http://www.linux-on-laptops.com/sony.html" "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1"
+ 151.56.71.198 - - [08/Feb/2007:12:57:42 +0000] "GET /data/css HTTP/1.1" 404 206 "http://www.rfi.net/suse-on-vaio.html" "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1"
+ 151.56.71.198 - - [08/Feb/2007:12:57:43 +0000] "GET /favicon.ico HTTP/1.1" 404 209 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1"
+ 217.113.68.60 - - [08/Feb/2007:13:02:15 +0000] "GET / HTTP/1.1" 304 - "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ 217.113.68.60 - - [08/Feb/2007:13:02:16 +0000] "GET /data/css HTTP/1.1" 404 206 "http://www.rfi.net/" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ debora.to.isac.cnr.it - - [08/Feb/2007:13:03:58 +0000] "GET /suse-on-vaio.html HTTP/1.1" 200 2858 "http://www.linux-on-laptops.com/sony.html" "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.0 (like Gecko)"
+ debora.to.isac.cnr.it - - [08/Feb/2007:13:03:58 +0000] "GET /data/css HTTP/1.1" 404 206 "http://www.rfi.net/suse-on-vaio.html" "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.0 (like Gecko)"
+ debora.to.isac.cnr.it - - [08/Feb/2007:13:03:58 +0000] "GET /favicon.ico HTTP/1.1" 404 209 "-" "Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.0 (like Gecko)"
+ 195.24.196.99 - - [08/Feb/2007:13:26:48 +0000] "GET / HTTP/1.0" 200 3309 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.8.0.9) Gecko/20061206 Firefox/1.5.0.9"
+ 195.24.196.99 - - [08/Feb/2007:13:26:58 +0000] "GET /data/css HTTP/1.0" 404 206 "http://www.rfi.net/" "Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.8.0.9) Gecko/20061206 Firefox/1.5.0.9"
+ 195.24.196.99 - - [08/Feb/2007:13:26:59 +0000] "GET /favicon.ico HTTP/1.0" 404 209 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.8.0.9) Gecko/20061206 Firefox/1.5.0.9"
+ crawl1.cosmixcorp.com - - [08/Feb/2007:13:27:57 +0000] "GET /robots.txt HTTP/1.0" 200 179 "-" "voyager/1.0"
+ crawl1.cosmixcorp.com - - [08/Feb/2007:13:28:25 +0000] "GET /links.html HTTP/1.0" 200 3413 "-" "voyager/1.0"
+ fhm226.internetdsl.tpnet.pl - - [08/Feb/2007:13:37:32 +0000] "GET /suse-on-vaio.html HTTP/1.1" 200 2858 "http://www.linux-on-laptops.com/sony.html" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ fhm226.internetdsl.tpnet.pl - - [08/Feb/2007:13:37:34 +0000] "GET /data/css HTTP/1.1" 404 206 "http://www.rfi.net/suse-on-vaio.html" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
+ 80.247.140.134 - - [08/Feb/2007:13:57:35 +0000] "GET / HTTP/1.1" 200 3309 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)"
+ 80.247.140.134 - - [08/Feb/2007:13:57:37 +0000] "GET /data/css HTTP/1.1" 404 206 "http://www.rfi.net" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)"
+ pop.compuscan.co.za - - [08/Feb/2007:14:10:43 +0000] "GET / HTTP/1.1" 200 3309 "-" "www.clamav.net"
+ livebot-207-46-98-57.search.live.com - - [08/Feb/2007:14:12:04 +0000] "GET /robots.txt HTTP/1.0" 200 179 "-" "msnbot/1.0 (+http://search.msn.com/msnbot.htm)"
+ livebot-207-46-98-57.search.live.com - - [08/Feb/2007:14:12:04 +0000] "GET /html/oracle.html HTTP/1.0" 404 214 "-" "msnbot/1.0 (+http://search.msn.com/msnbot.htm)"
+ dslb-088-064-005-154.pools.arcor-ip.net - - [08/Feb/2007:14:12:15 +0000] "GET / HTTP/1.1" 200 3309 "-" "www.clamav.net"
+ 196.201.92.41 - - [08/Feb/2007:14:15:01 +0000] "GET / HTTP/1.1" 200 3309 "-" "MOT-L7/08.B7.DCR MIB/2.2.1 Profile/MIDP-2.0 Configuration/CLDC-1.1"
+
+The specific task here is to sort the 286,525 lines of this file by Response
+Code, Query, Browser, Referring Url, and lastly Date. One solution might be to
+use the following code, which iterates over the files given on the
+command-line.
+
+# sort-apache-log
+
+ #!/usr/bin/perl -n
+
+ use strict;
+ use warnings;
+
+ my @data;
+
+ LINE:
+ while ( <> ) {
+ my $line = $_;
+ if (
+ $line =~ m/^(
+ ([\w\.\-]+) # client
+ \s*-\s*-\s*\[
+ ([^]]+) # date
+ \]\s*"\w+\s*
+ (\S+) # query
+ [^"]+"\s*
+ (\d+) # status
+ \s+\S+\s+"[^"]*"\s+"
+ ([^"]*) # browser
+ "
+ .*
+ )$/x
+ ) {
+ my @chunks = split(/ +/, $line);
+ my $ip = $1;
+ my $date = $2;
+ my $query = $3;
+ my $status = $4;
+ my $browser = $5;
+
+ push(@data, [$ip, $date, $query, $status, $browser, $line]);
+ }
+ }
+
+ my @sorted = sort {
+ $a->[3] cmp $b->[3]
+ ||
+ $a->[2] cmp $b->[2]
+ ||
+ $a->[0] cmp $b->[0]
+ ||
+ $a->[1] cmp $b->[1]
+ ||
+ $a->[4] cmp $b->[4]
+ } @data;
+
+ foreach my $data ( @sorted ) {
+ print $data->[5];
+ }
+
+ exit 0;
+
+When running this program, redirect C<STDOUT> so it is possible to check the
+output is correct from following test runs and use the system C<time> utility
+to check the overall runtime.
+
+ $> time ./sort-apache-log logfile > out-sort
+
+ real 0m17.371s
+ user 0m15.757s
+ sys 0m0.592s
+
+The program took just over 17 wallclock seconds to run. Note the different
+values C<time> outputs, it's important to always use the same one, and to not
+confuse what each one means.
+
+=over 4
+
+=item Elapsed Real Time
+
+The overall, or wallclock, time between when C<time> was called, and when it
+terminates. The elapsed time includes both user and system times, and time
+spent waiting for other users and processes on the system. Inevitably, this is
+the most approximate of the measurements given.
+
+=item User CPU Time
+
+The user time is the amount of time the entire process spent on behalf of the
+user on this system executing this program.
+
+=item System CPU Time
+
+The system time is the amount of time the kernel itself spent executing
+routines, or system calls, on behalf of this process user.
+
+=back
+
+Running this same process as a C<Schwarzian Transform> it is possible to
+eliminate the input and output arrays for storing all the data, and work on the
+input directly as it arrives too. Otherwise, the code looks fairly similar:
+
+# sort-apache-log-schwarzian
+
+ #!/usr/bin/perl -n
+
+ use strict;
+ use warnings;
+
+ print
+
+ map $_->[0] =>
+
+ sort {
+ $a->[4] cmp $b->[4]
+ ||
+ $a->[3] cmp $b->[3]
+ ||
+ $a->[1] cmp $b->[1]
+ ||
+ $a->[2] cmp $b->[2]
+ ||
+ $a->[5] cmp $b->[5]
+ }
+ map [ $_, m/^(
+ ([\w\.\-]+) # client
+ \s*-\s*-\s*\[
+ ([^]]+) # date
+ \]\s*"\w+\s*
+ (\S+) # query
+ [^"]+"\s*
+ (\d+) # status
+ \s+\S+\s+"[^"]*"\s+"
+ ([^"]*) # browser
+ "
+ .*
+ )$/xo ]
+
+ => <>;
+
+ exit 0;
+
+Run the new code against the same logfile, as above, to check the new time.
+
+ $> time ./sort-apache-log-schwarzian logfile > out-schwarz
+
+ real 0m9.664s
+ user 0m8.873s
+ sys 0m0.704s
+
+The time has been cut in half, which is a respectable speed improvement by any
+standard. Naturally, it is important to check the output is consistent with
+the first program run, this is where the Unix system C<cksum> utility comes in.
+
+ $> cksum out-sort out-schwarz
+ 3044173777 52029194 out-sort
+ 3044173777 52029194 out-schwarz
+
+BTW. Beware too of pressure from managers who see you speed a program up by 50%
+of the runtime once, only to get a request one month later to do the same again
+(true story) - you'll just have to point out your only human, even if you are a
+Perl programmer, and you'll see what you can do...
+
+=head1 LOGGING
+
+An essential part of any good development process is appropriate error handling
+with appropriately informative messages, however there exists a school of
+thought which suggests that log files should be I<chatty>, as if the chain of
+unbroken output somehow ensures the survival of the program. If speed is in
+any way an issue, this approach is wrong.
+
+A common sight is code which looks something like this:
+
+ logger->debug( "A logging message via process-id: $$ INC: " . Dumper(\%INC) )
+
+The problem is that this code will always be parsed and executed, even when the
+debug level set in the logging configuration file is zero. Once the debug()
+subroutine has been entered, and the internal C<$debug> variable confirmed to
+be zero, for example, the message which has been sent in will be discarded and
+the program will continue. In the example given though, the \%INC hash will
+already have been dumped, and the message string constructed, all of which work
+could be bypassed by a debug variable at the statement level, like this:
+
+ logger->debug( "A logging message via process-id: $$ INC: " . Dumper(\%INC) ) if $DEBUG;
+
+This effect can be demonstrated by setting up a test script with both forms,
+including a C<debug()> subroutine to emulate typical C<logger()> functionality.
+
+# ifdebug
+
+ #!/usr/bin/perl
+
+ use strict;
+ use warnings;
+
+ use Benchmark;
+ use Data::Dumper;
+ my $DEBUG = 0;
+
+ sub debug {
+ my $msg = shift;
+
+ if ( $DEBUG ) {
+ print "DEBUG: $msg\n";
+ }
+ };
+
+ timethese(100000, {
+ 'debug' => sub {
+ debug( "A $0 logging message via process-id: $$" . Dumper(\%INC) )
+ },
+ 'ifdebug' => sub {
+ debug( "A $0 logging message via process-id: $$" . Dumper(\%INC) ) if $DEBUG
+ },
+ });
+
+Let's see what C<Benchmark> makes of this:
+
+ $> perl ifdebug
+ Benchmark: timing 100000 iterations of constant, sub...
+ ifdebug: 0 wallclock secs ( 0.01 usr + 0.00 sys = 0.01 CPU) @ 10000000.00/s (n=100000)
+ (warning: too few iterations for a reliable count)
+ debug: 14 wallclock secs (13.18 usr + 0.04 sys = 13.22 CPU) @ 7564.30/s (n=100000)
+
+In the one case the code, which does exactly the same thing as far as
+outputting any debugging information is concerned, in other words nothing,
+takes 14 seconds, and in the other case the code takes one hundredth of a
+second. Looks fairly definitive. Use a C<$DEBUG> variable BEFORE you call the
+subroutine, rather than relying on the smart functionality inside it.
+
+=head2 Logging if DEBUG (constant)
+
+It's possible to take the previous idea a little further, by using a compile
+time C<DEBUG> constant.
+
+# ifdebug-constant
+
+ #!/usr/bin/perl
+
+ use strict;
+ use warnings;
+
+ use Benchmark;
+ use Data::Dumper;
+ use constant
+ DEBUG => 0
+ ;
+
+ sub debug {
+ if ( DEBUG ) {
+ my $msg = shift;
+ print "DEBUG: $msg\n";
+ }
+ };
+
+ timethese(100000, {
+ 'debug' => sub {
+ debug( "A $0 logging message via process-id: $$" . Dumper(\%INC) )
+ },
+ 'constant' => sub {
+ debug( "A $0 logging message via process-id: $$" . Dumper(\%INC) ) if DEBUG
+ },
+ });
+
+Running this program produces the following output:
+
+ $> perl ifdebug-constant
+ Benchmark: timing 100000 iterations of constant, sub...
+ constant: 0 wallclock secs (-0.00 usr + 0.00 sys = -0.00 CPU) @ -7205759403792793600000.00/s (n=100000)
+ (warning: too few iterations for a reliable count)
+ sub: 14 wallclock secs (13.09 usr + 0.00 sys = 13.09 CPU) @ 7639.42/s (n=100000)
+
+The C<DEBUG> constant wipes the floor with even the C<$debug> variable,
+clocking in at minus zero seconds, and generates a "warning: too few iterations
+for a reliable count" message into the bargain. To see what is really going
+on, and why we had too few iterations when we thought we asked for 100000, we
+can use the very useful C<B::Deparse> to inspect the new code:
+
+ $> perl -MO=Deparse ifdebug-constant
+
+ use Benchmark;
+ use Data::Dumper;
+ use constant ('DEBUG', 0);
+ sub debug {
+ use warnings;
+ use strict 'refs';
+ 0;
+ }
+ use warnings;
+ use strict 'refs';
+ timethese(100000, {'sub', sub {
+ debug "A $0 logging message via process-id: $$" . Dumper(\%INC);
+ }
+ , 'constant', sub {
+ 0;
+ }
+ });
+ ifdebug-constant syntax OK
+
+The output shows the constant() subroutine we're testing being replaced with
+the value of the C<DEBUG> constant: zero. The line to be tested has been
+completely optimized away, and you can't get much more efficient than that.
+
+=head1 POSTSCRIPT
+
+This document has provided several way to go about identifying hot-spots, and
+checking whether any modifications have improved the runtime of the code.
+
+As a final thought, remember that it's not (at the time of writing) possible to
+produce a useful program which will run in zero or negative time and this basic
+principle can be written as: I<useful programs are slow> by their very
+definition. It is of course possible to write a nearly instantaneous program,
+but it's not going to do very much, here's a very efficient one:
+
+ $> perl -e 0
+
+Optimizing that any further is a job for C<p5p>.
+
+=head1 SEE ALSO
+
+Further reading can be found using the modules and links below.
+
+=head2 PERLDOCS
+
+For example: C<perldoc -f sort>.
+
+L<perlfaq4>.
+
+L<perlfork>, L<perlfunc>, L<perlretut>, L<perlthrtut>.
+
+L<threads>.
+
+=head2 MAN PAGES
+
+C<time>.
+
+=head2 MODULES
+
+It's not possible to individually showcase all the performance related code for
+Perl here, naturally, but here's a short list of modules from the CPAN which
+deserve further attention.
+
+ Apache::DProf
+ Apache::SmallProf
+ Benchmark
+ DBIx::Profiler
+ Devel::AutoProfiler
+ Devel::DProf
+ Devel::DProfLB
+ Devel::FastProf
+ Devel::GraphVizProf
+ Devel::NYTProf
+ Devel::NYTProf::Apache
+ Devel::Profiler
+ Devel::Profile
+ Devel::Profit
+ Devel::SmallProf
+ Devel::WxProf
+ POE::Devel::Profiler
+ Sort::Key
+ Sort::Maker
+
+=head2 URLS
+
+Very useful online reference material:
+
+ http://www.ccl4.org/~nick/P/Fast_Enough/
+
+ http://www-128.ibm.com/developerworks/library/l-optperl.html
+
+ http://perlbuzz.com/2007/11/bind-output-variables-in-dbi-for-speed-and-safety.html
+
+ http://en.wikipedia.org/wiki/Performance_analysis
+
+ http://apache.perl.org/docs/1.0/guide/performance.html
+
+ http://perlgolf.sourceforge.net/
+
+ http://www.sysarch.com/Perl/sort_paper.html
+
+=head1 AUTHOR
+
+Richard Foley <richard.foley@rfi.net> Copyright (c) 2008
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlplan9.pod b/Master/tlpkg/tlperl/lib/pods/perlplan9.pod
new file mode 100644
index 00000000000..5e53c05bdb9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlplan9.pod
@@ -0,0 +1,146 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+perlplan9 - Plan 9-specific documentation for Perl
+
+=head1 DESCRIPTION
+
+These are a few notes describing features peculiar to
+Plan 9 Perl. As such, it is not intended to be a replacement
+for the rest of the Perl 5 documentation (which is both
+copious and excellent). If you have any questions to
+which you can't find answers in these man pages, contact
+Luther Huffman at lutherh@stratcom.com and we'll try to
+answer them.
+
+=head2 Invoking Perl
+
+Perl is invoked from the command line as described in
+L<perl>. Most perl scripts, however, do have a first line
+such as "#!/usr/local/bin/perl". This is known as a shebang
+(shell-bang) statement and tells the OS shell where to find
+the perl interpreter. In Plan 9 Perl this statement should be
+"#!/bin/perl" if you wish to be able to directly invoke the
+script by its name.
+ Alternatively, you may invoke perl with the command "Perl"
+instead of "perl". This will produce Acme-friendly error
+messages of the form "filename:18".
+
+Some scripts, usually identified with a *.PL extension, are
+self-configuring and are able to correctly create their own
+shebang path from config information located in Plan 9
+Perl. These you won't need to be worried about.
+
+=head2 What's in Plan 9 Perl
+
+Although Plan 9 Perl currently only provides static
+loading, it is built with a number of useful extensions.
+These include Opcode, FileHandle, Fcntl, and POSIX. Expect
+to see others (and DynaLoading!) in the future.
+
+=head2 What's not in Plan 9 Perl
+
+As mentioned previously, dynamic loading isn't currently
+available nor is MakeMaker. Both are high-priority items.
+
+=head2 Perl5 Functions not currently supported in Plan 9 Perl
+
+Some, such as C<chown> and C<umask> aren't provided
+because the concept does not exist within Plan 9. Others,
+such as some of the socket-related functions, simply
+haven't been written yet. Many in the latter category
+may be supported in the future.
+
+The functions not currently implemented include:
+
+ chown, chroot, dbmclose, dbmopen, getsockopt,
+ setsockopt, recvmsg, sendmsg, getnetbyname,
+ getnetbyaddr, getnetent, getprotoent, getservent,
+ sethostent, setnetent, setprotoent, setservent,
+ endservent, endnetent, endprotoent, umask
+
+There may be several other functions that have undefined
+behavior so this list shouldn't be considered complete.
+
+=head2 Signals in Plan 9 Perl
+
+For compatibility with perl scripts written for the Unix
+environment, Plan 9 Perl uses the POSIX signal emulation
+provided in Plan 9's ANSI POSIX Environment (APE). Signal stacking
+isn't supported. The signals provided are:
+
+ SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGABRT,
+ SIGFPE, SIGKILL, SIGSEGV, SIGPIPE, SIGPIPE, SIGALRM,
+ SIGTERM, SIGUSR1, SIGUSR2, SIGCHLD, SIGCONT,
+ SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU
+
+=head1 COMPILING AND INSTALLING PERL ON PLAN 9
+
+WELCOME to Plan 9 Perl, brave soul!
+
+ This is a preliminary alpha version of Plan 9 Perl. Still to be
+implemented are MakeMaker and DynaLoader. Many perl commands are
+missing or currently behave in an inscrutable manner. These gaps will,
+with perseverance and a modicum of luck, be remedied in the near
+future.To install this software:
+
+1. Create the source directories and libraries for perl by running the
+plan9/setup.rc command (i.e., located in the plan9 subdirectory).
+Note: the setup routine assumes that you haven't dearchived these
+files into /sys/src/cmd/perl. After running setup.rc you may delete
+the copy of the source you originally detarred, as source code has now
+been installed in /sys/src/cmd/perl. If you plan on installing perl
+binaries for all architectures, run "setup.rc -a".
+
+2. After making sure that you have adequate privileges to build system
+software, from /sys/src/cmd/perl/5.00301 (adjust version
+appropriately) run:
+
+ mk install
+
+If you wish to install perl versions for all architectures (68020,
+mips, sparc and 386) run:
+
+ mk installall
+
+3. Wait. The build process will take a *long* time because perl
+bootstraps itself. A 75MHz Pentium, 16MB RAM machine takes roughly 30
+minutes to build the distribution from scratch.
+
+=head2 Installing Perl Documentation on Plan 9
+
+This perl distribution comes with a tremendous amount of
+documentation. To add these to the built-in manuals that come with
+Plan 9, from /sys/src/cmd/perl/5.00301 (adjust version appropriately)
+run:
+
+ mk man
+
+To begin your reading, start with:
+
+ man perl
+
+This is a good introduction and will direct you towards other man
+pages that may interest you.
+
+(Note: "mk man" may produce some extraneous noise. Fear not.)
+
+=head1 BUGS
+
+"As many as there are grains of sand on all the beaches of the
+world . . ." - Carl Sagan
+
+=head1 Revision date
+
+This document was revised 09-October-1996 for Perl 5.003_7.
+
+=head1 AUTHOR
+
+Direct questions, comments, and the unlikely bug report (ahem) direct
+comments toward:
+
+Luther Huffman, lutherh@stratcom.com,
+Strategic Computer Solutions, Inc.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlpod.pod b/Master/tlpkg/tlperl/lib/pods/perlpod.pod
new file mode 100644
index 00000000000..90bc5b1d8f8
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlpod.pod
@@ -0,0 +1,737 @@
+
+=for comment
+This document is in Pod format. To read this, use a Pod formatter,
+like "perldoc perlpod".
+
+=head1 NAME
+X<POD> X<plain old documentation>
+
+perlpod - the Plain Old Documentation format
+
+=head1 DESCRIPTION
+
+Pod is a simple-to-use markup language used for writing documentation
+for Perl, Perl programs, and Perl modules.
+
+Translators are available for converting Pod to various formats
+like plain text, HTML, man pages, and more.
+
+Pod markup consists of three basic kinds of paragraphs:
+L<ordinary|/"Ordinary Paragraph">,
+L<verbatim|/"Verbatim Paragraph">, and
+L<command|/"Command Paragraph">.
+
+
+=head2 Ordinary Paragraph
+X<POD, ordinary paragraph>
+
+Most paragraphs in your documentation will be ordinary blocks
+of text, like this one. You can simply type in your text without
+any markup whatsoever, and with just a blank line before and
+after. When it gets formatted, it will undergo minimal formatting,
+like being rewrapped, probably put into a proportionally spaced
+font, and maybe even justified.
+
+You can use formatting codes in ordinary paragraphs, for B<bold>,
+I<italic>, C<code-style>, L<hyperlinks|perlfaq>, and more. Such
+codes are explained in the "L<Formatting Codes|/"Formatting Codes">"
+section, below.
+
+
+=head2 Verbatim Paragraph
+X<POD, verbatim paragraph> X<verbatim>
+
+Verbatim paragraphs are usually used for presenting a codeblock or
+other text which does not require any special parsing or formatting,
+and which shouldn't be wrapped.
+
+A verbatim paragraph is distinguished by having its first character
+be a space or a tab. (And commonly, all its lines begin with spaces
+and/or tabs.) It should be reproduced exactly, with tabs assumed to
+be on 8-column boundaries. There are no special formatting codes,
+so you can't italicize or anything like that. A \ means \, and
+nothing else.
+
+
+=head2 Command Paragraph
+X<POD, command>
+
+A command paragraph is used for special treatment of whole chunks
+of text, usually as headings or parts of lists.
+
+All command paragraphs (which are typically only one line long) start
+with "=", followed by an identifier, followed by arbitrary text that
+the command can use however it pleases. Currently recognized commands
+are
+
+ =pod
+ =head1 Heading Text
+ =head2 Heading Text
+ =head3 Heading Text
+ =head4 Heading Text
+ =over indentlevel
+ =item stuff
+ =back
+ =begin format
+ =end format
+ =for format text...
+ =encoding type
+ =cut
+
+To explain them each in detail:
+
+=over
+
+=item C<=head1 I<Heading Text>>
+X<=head1> X<=head2> X<=head3> X<=head4>
+X<head1> X<head2> X<head3> X<head4>
+
+=item C<=head2 I<Heading Text>>
+
+=item C<=head3 I<Heading Text>>
+
+=item C<=head4 I<Heading Text>>
+
+Head1 through head4 produce headings, head1 being the highest
+level. The text in the rest of this paragraph is the content of the
+heading. For example:
+
+ =head2 Object Attributes
+
+The text "Object Attributes" comprises the heading there. (Note that
+head3 and head4 are recent additions, not supported in older Pod
+translators.) The text in these heading commands can use
+formatting codes, as seen here:
+
+ =head2 Possible Values for C<$/>
+
+Such commands are explained in the
+"L<Formatting Codes|/"Formatting Codes">" section, below.
+
+=item C<=over I<indentlevel>>
+X<=over> X<=item> X<=back> X<over> X<item> X<back>
+
+=item C<=item I<stuff...>>
+
+=item C<=back>
+
+Item, over, and back require a little more explanation: "=over" starts
+a region specifically for the generation of a list using "=item"
+commands, or for indenting (groups of) normal paragraphs. At the end
+of your list, use "=back" to end it. The I<indentlevel> option to
+"=over" indicates how far over to indent, generally in ems (where
+one em is the width of an "M" in the document's base font) or roughly
+comparable units; if there is no I<indentlevel> option, it defaults
+to four. (And some formatters may just ignore whatever I<indentlevel>
+you provide.) In the I<stuff> in C<=item I<stuff...>>, you may
+use formatting codes, as seen here:
+
+ =item Using C<$|> to Control Buffering
+
+Such commands are explained in the
+"L<Formatting Codes|/"Formatting Codes">" section, below.
+
+Note also that there are some basic rules to using "=over" ...
+"=back" regions:
+
+=over
+
+=item *
+
+Don't use "=item"s outside of an "=over" ... "=back" region.
+
+=item *
+
+The first thing after the "=over" command should be an "=item", unless
+there aren't going to be any items at all in this "=over" ... "=back"
+region.
+
+=item *
+
+Don't put "=headI<n>" commands inside an "=over" ... "=back" region.
+
+=item *
+
+And perhaps most importantly, keep the items consistent: either use
+"=item *" for all of them, to produce bullets; or use "=item 1.",
+"=item 2.", etc., to produce numbered lists; or use "=item foo",
+"=item bar", etc.--namely, things that look nothing like bullets or
+numbers.
+
+If you start with bullets or numbers, stick with them, as
+formatters use the first "=item" type to decide how to format the
+list.
+
+=back
+
+=item C<=cut>
+X<=cut> X<cut>
+
+To end a Pod block, use a blank line,
+then a line beginning with "=cut", and a blank
+line after it. This lets Perl (and the Pod formatter) know that
+this is where Perl code is resuming. (The blank line before the "=cut"
+is not technically necessary, but many older Pod processors require it.)
+
+=item C<=pod>
+X<=pod> X<pod>
+
+The "=pod" command by itself doesn't do much of anything, but it
+signals to Perl (and Pod formatters) that a Pod block starts here. A
+Pod block starts with I<any> command paragraph, so a "=pod" command is
+usually used just when you want to start a Pod block with an ordinary
+paragraph or a verbatim paragraph. For example:
+
+ =item stuff()
+
+ This function does stuff.
+
+ =cut
+
+ sub stuff {
+ ...
+ }
+
+ =pod
+
+ Remember to check its return value, as in:
+
+ stuff() || die "Couldn't do stuff!";
+
+ =cut
+
+=item C<=begin I<formatname>>
+X<=begin> X<=end> X<=for> X<begin> X<end> X<for>
+
+=item C<=end I<formatname>>
+
+=item C<=for I<formatname> I<text...>>
+
+For, begin, and end will let you have regions of text/code/data that
+are not generally interpreted as normal Pod text, but are passed
+directly to particular formatters, or are otherwise special. A
+formatter that can use that format will use the region, otherwise it
+will be completely ignored.
+
+A command "=begin I<formatname>", some paragraphs, and a
+command "=end I<formatname>", mean that the text/data in between
+is meant for formatters that understand the special format
+called I<formatname>. For example,
+
+ =begin html
+
+ <hr> <img src="thang.png">
+ <p> This is a raw HTML paragraph </p>
+
+ =end html
+
+The command "=for I<formatname> I<text...>"
+specifies that the remainder of just this paragraph (starting
+right after I<formatname>) is in that special format.
+
+ =for html <hr> <img src="thang.png">
+ <p> This is a raw HTML paragraph </p>
+
+This means the same thing as the above "=begin html" ... "=end html"
+region.
+
+That is, with "=for", you can have only one paragraph's worth
+of text (i.e., the text in "=foo targetname text..."), but with
+"=begin targetname" ... "=end targetname", you can have any amount
+of stuff inbetween. (Note that there still must be a blank line
+after the "=begin" command and a blank line before the "=end"
+command.
+
+Here are some examples of how to use these:
+
+ =begin html
+
+ <br>Figure 1.<br><IMG SRC="figure1.png"><br>
+
+ =end html
+
+ =begin text
+
+ ---------------
+ | foo |
+ | bar |
+ ---------------
+
+ ^^^^ Figure 1. ^^^^
+
+ =end text
+
+Some format names that formatters currently are known to accept
+include "roff", "man", "latex", "tex", "text", and "html". (Some
+formatters will treat some of these as synonyms.)
+
+A format name of "comment" is common for just making notes (presumably
+to yourself) that won't appear in any formatted version of the Pod
+document:
+
+ =for comment
+ Make sure that all the available options are documented!
+
+Some I<formatnames> will require a leading colon (as in
+C<"=for :formatname">, or
+C<"=begin :formatname" ... "=end :formatname">),
+to signal that the text is not raw data, but instead I<is> Pod text
+(i.e., possibly containing formatting codes) that's just not for
+normal formatting (e.g., may not be a normal-use paragraph, but might
+be for formatting as a footnote).
+
+=item C<=encoding I<encodingname>>
+X<=encoding> X<encoding>
+
+This command is used for declaring the encoding of a document. Most
+users won't need this; but if your encoding isn't US-ASCII or Latin-1,
+then put a C<=encoding I<encodingname>> command early in the document so
+that pod formatters will know how to decode the document. For
+I<encodingname>, use a name recognized by the L<Encode::Supported>
+module. Examples:
+
+ =encoding utf8
+
+ =encoding koi8-r
+
+ =encoding ShiftJIS
+
+ =encoding big5
+
+=back
+
+C<=encoding> affects the whole document, and must occur only once.
+
+And don't forget, when using any other command, that the command lasts up
+until the end of its I<paragraph>, not its line. So in the
+examples below, you can see that every command needs the blank
+line after it, to end its paragraph.
+
+Some examples of lists include:
+
+ =over
+
+ =item *
+
+ First item
+
+ =item *
+
+ Second item
+
+ =back
+
+ =over
+
+ =item Foo()
+
+ Description of Foo function
+
+ =item Bar()
+
+ Description of Bar function
+
+ =back
+
+
+=head2 Formatting Codes
+X<POD, formatting code> X<formatting code>
+X<POD, interior sequence> X<interior sequence>
+
+In ordinary paragraphs and in some command paragraphs, various
+formatting codes (a.k.a. "interior sequences") can be used:
+
+=for comment
+ "interior sequences" is such an opaque term.
+ Prefer "formatting codes" instead.
+
+=over
+
+=item C<IE<lt>textE<gt>> -- italic text
+X<I> X<< IZ<><> >> X<POD, formatting code, italic> X<italic>
+
+Used for emphasis ("C<be IE<lt>careful!E<gt>>") and parameters
+("C<redo IE<lt>LABELE<gt>>")
+
+=item C<BE<lt>textE<gt>> -- bold text
+X<B> X<< BZ<><> >> X<POD, formatting code, bold> X<bold>
+
+Used for switches ("C<perl's BE<lt>-nE<gt> switch>"), programs
+("C<some systems provide a BE<lt>chfnE<gt> for that>"),
+emphasis ("C<be BE<lt>careful!E<gt>>"), and so on
+("C<and that feature is known as BE<lt>autovivificationE<gt>>").
+
+=item C<CE<lt>codeE<gt>> -- code text
+X<C> X<< CZ<><> >> X<POD, formatting code, code> X<code>
+
+Renders code in a typewriter font, or gives some other indication that
+this represents program text ("C<CE<lt>gmtime($^T)E<gt>>") or some other
+form of computerese ("C<CE<lt>drwxr-xr-xE<gt>>").
+
+=item C<LE<lt>nameE<gt>> -- a hyperlink
+X<L> X<< LZ<><> >> X<POD, formatting code, hyperlink> X<hyperlink>
+
+There are various syntaxes, listed below. In the syntaxes given,
+C<text>, C<name>, and C<section> cannot contain the characters
+'/' and '|'; and any '<' or '>' should be matched.
+
+=over
+
+=item *
+
+C<LE<lt>nameE<gt>>
+
+Link to a Perl manual page (e.g., C<LE<lt>Net::PingE<gt>>). Note
+that C<name> should not contain spaces. This syntax
+is also occasionally used for references to Unix man pages, as in
+C<LE<lt>crontab(5)E<gt>>.
+
+=item *
+
+C<LE<lt>name/"sec"E<gt>> or C<LE<lt>name/secE<gt>>
+
+Link to a section in other manual page. E.g.,
+C<LE<lt>perlsyn/"For Loops"E<gt>>
+
+=item *
+
+C<LE<lt>/"sec"E<gt>> or C<LE<lt>/secE<gt>>
+
+Link to a section in this manual page. E.g.,
+C<LE<lt>/"Object Methods"E<gt>>
+
+=back
+
+A section is started by the named heading or item. For
+example, C<LE<lt>perlvar/$.E<gt>> or C<LE<lt>perlvar/"$."E<gt>> both
+link to the section started by "C<=item $.>" in perlvar. And
+C<LE<lt>perlsyn/For LoopsE<gt>> or C<LE<lt>perlsyn/"For Loops"E<gt>>
+both link to the section started by "C<=head2 For Loops>"
+in perlsyn.
+
+To control what text is used for display, you
+use "C<LE<lt>text|...E<gt>>", as in:
+
+=over
+
+=item *
+
+C<LE<lt>text|nameE<gt>>
+
+Link this text to that manual page. E.g.,
+C<LE<lt>Perl Error Messages|perldiagE<gt>>
+
+=item *
+
+C<LE<lt>text|name/"sec"E<gt>> or C<LE<lt>text|name/secE<gt>>
+
+Link this text to that section in that manual page. E.g.,
+C<LE<lt>postfix "if"|perlsyn/"Statement Modifiers"E<gt>>
+
+=item *
+
+C<LE<lt>text|/"sec"E<gt>> or C<LE<lt>text|/secE<gt>>
+or C<LE<lt>text|"sec"E<gt>>
+
+Link this text to that section in this manual page. E.g.,
+C<LE<lt>the various attributes|/"Member Data"E<gt>>
+
+=back
+
+Or you can link to a web page:
+
+=over
+
+=item *
+
+C<LE<lt>scheme:...E<gt>>
+
+C<LE<lt>text|scheme:...E<gt>>
+
+Links to an absolute URL. For example, C<LE<lt>http://www.perl.org/E<gt>> or
+C<LE<lt>The Perl Home Page|http://www.perl.org/E<gt>>.
+
+=back
+
+=item C<EE<lt>escapeE<gt>> -- a character escape
+X<E> X<< EZ<><> >> X<POD, formatting code, escape> X<escape>
+
+Very similar to HTML/XML C<&I<foo>;> "entity references":
+
+=over
+
+=item *
+
+C<EE<lt>ltE<gt>> -- a literal E<lt> (less than)
+
+=item *
+
+C<EE<lt>gtE<gt>> -- a literal E<gt> (greater than)
+
+=item *
+
+C<EE<lt>verbarE<gt>> -- a literal | (I<ver>tical I<bar>)
+
+=item *
+
+C<EE<lt>solE<gt>> = a literal / (I<sol>idus)
+
+The above four are optional except in other formatting codes,
+notably C<LE<lt>...E<gt>>, and when preceded by a
+capital letter.
+
+=item *
+
+C<EE<lt>htmlnameE<gt>>
+
+Some non-numeric HTML entity name, such as C<EE<lt>eacuteE<gt>>,
+meaning the same thing as C<&eacute;> in HTML -- i.e., a lowercase
+e with an acute (/-shaped) accent.
+
+=item *
+
+C<EE<lt>numberE<gt>>
+
+The ASCII/Latin-1/Unicode character with that number. A
+leading "0x" means that I<number> is hex, as in
+C<EE<lt>0x201EE<gt>>. A leading "0" means that I<number> is octal,
+as in C<EE<lt>075E<gt>>. Otherwise I<number> is interpreted as being
+in decimal, as in C<EE<lt>181E<gt>>.
+
+Note that older Pod formatters might not recognize octal or
+hex numeric escapes, and that many formatters cannot reliably
+render characters above 255. (Some formatters may even have
+to use compromised renderings of Latin-1 characters, like
+rendering C<EE<lt>eacuteE<gt>> as just a plain "e".)
+
+=back
+
+=item C<FE<lt>filenameE<gt>> -- used for filenames
+X<F> X<< FZ<><> >> X<POD, formatting code, filename> X<filename>
+
+Typically displayed in italics. Example: "C<FE<lt>.cshrcE<gt>>"
+
+=item C<SE<lt>textE<gt>> -- text contains non-breaking spaces
+X<S> X<< SZ<><> >> X<POD, formatting code, non-breaking space>
+X<non-breaking space>
+
+This means that the words in I<text> should not be broken
+across lines. Example: S<C<SE<lt>$x ? $y : $zE<gt>>>.
+
+=item C<XE<lt>topic nameE<gt>> -- an index entry
+X<X> X<< XZ<><> >> X<POD, formatting code, index entry> X<index entry>
+
+This is ignored by most formatters, but some may use it for building
+indexes. It always renders as empty-string.
+Example: C<XE<lt>absolutizing relative URLsE<gt>>
+
+=item C<ZE<lt>E<gt>> -- a null (zero-effect) formatting code
+X<Z> X<< ZZ<><> >> X<POD, formatting code, null> X<null>
+
+This is rarely used. It's one way to get around using an
+EE<lt>...E<gt> code sometimes. For example, instead of
+"C<NEE<lt>ltE<gt>3>" (for "NE<lt>3") you could write
+"C<NZE<lt>E<gt>E<lt>3>" (the "ZE<lt>E<gt>" breaks up the "N" and
+the "E<lt>" so they can't be considered
+the part of a (fictitious) "NE<lt>...E<gt>" code.
+
+=for comment
+ This was formerly explained as a "zero-width character". But it in
+ most parser models, it parses to nothing at all, as opposed to parsing
+ as if it were a E<zwnj> or E<zwj>, which are REAL zero-width characters.
+ So "width" and "character" are exactly the wrong words.
+
+=back
+
+Most of the time, you will need only a single set of angle brackets to
+delimit the beginning and end of formatting codes. However,
+sometimes you will want to put a real right angle bracket (a
+greater-than sign, '>') inside of a formatting code. This is particularly
+common when using a formatting code to provide a different font-type for a
+snippet of code. As with all things in Perl, there is more than
+one way to do it. One way is to simply escape the closing bracket
+using an C<E> code:
+
+ C<$a E<lt>=E<gt> $b>
+
+This will produce: "C<$a E<lt>=E<gt> $b>"
+
+A more readable, and perhaps more "plain" way is to use an alternate
+set of delimiters that doesn't require a single ">" to be escaped.
+Doubled angle brackets ("<<" and ">>") may be used I<if and only if there is
+whitespace right after the opening delimiter and whitespace right
+before the closing delimiter!> For example, the following will
+do the trick:
+X<POD, formatting code, escaping with multiple brackets>
+
+ C<< $a <=> $b >>
+
+In fact, you can use as many repeated angle-brackets as you like so
+long as you have the same number of them in the opening and closing
+delimiters, and make sure that whitespace immediately follows the last
+'<' of the opening delimiter, and immediately precedes the first '>'
+of the closing delimiter. (The whitespace is ignored.) So the
+following will also work:
+X<POD, formatting code, escaping with multiple brackets>
+
+ C<<< $a <=> $b >>>
+ C<<<< $a <=> $b >>>>
+
+And they all mean exactly the same as this:
+
+ C<$a E<lt>=E<gt> $b>
+
+The multiple-bracket form does not affect the interpretation of the contents of
+the formatting code, only how it must end. That means that the examples above
+are also exactly the same as this:
+
+ C<< $a E<lt>=E<gt> $b >>
+
+As a further example, this means that if you wanted to put these bits of
+code in C<C> (code) style:
+
+ open(X, ">>thing.dat") || die $!
+ $foo->bar();
+
+you could do it like so:
+
+ C<<< open(X, ">>thing.dat") || die $! >>>
+ C<< $foo->bar(); >>
+
+which is presumably easier to read than the old way:
+
+ C<open(X, "E<gt>E<gt>thing.dat") || die $!>
+ C<$foo-E<gt>bar();>
+
+This is currently supported by pod2text (Pod::Text), pod2man (Pod::Man),
+and any other pod2xxx or Pod::Xxxx translators that use
+Pod::Parser 1.093 or later, or Pod::Tree 1.02 or later.
+
+=head2 The Intent
+X<POD, intent of>
+
+The intent is simplicity of use, not power of expression. Paragraphs
+look like paragraphs (block format), so that they stand out
+visually, and so that I could run them through C<fmt> easily to reformat
+them (that's F7 in my version of B<vi>, or Esc Q in my version of
+B<emacs>). I wanted the translator to always leave the C<'> and C<`> and
+C<"> quotes alone, in verbatim mode, so I could slurp in a
+working program, shift it over four spaces, and have it print out, er,
+verbatim. And presumably in a monospace font.
+
+The Pod format is not necessarily sufficient for writing a book. Pod
+is just meant to be an idiot-proof common source for nroff, HTML,
+TeX, and other markup languages, as used for online
+documentation. Translators exist for B<pod2text>, B<pod2html>,
+B<pod2man> (that's for nroff(1) and troff(1)), B<pod2latex>, and
+B<pod2fm>. Various others are available in CPAN.
+
+
+=head2 Embedding Pods in Perl Modules
+X<POD, embedding>
+
+You can embed Pod documentation in your Perl modules and scripts.
+Start your documentation with an empty line, a "=head1" command at the
+beginning, and end it with a "=cut" command and an empty line. Perl
+will ignore the Pod text. See any of the supplied library modules for
+examples. If you're going to put your Pod at the end of the file, and
+you're using an __END__ or __DATA__ cut mark, make sure to put an
+empty line there before the first Pod command.
+
+ __END__
+
+ =head1 NAME
+
+ Time::Local - efficiently compute time from local and GMT time
+
+Without that empty line before the "=head1", many translators wouldn't
+have recognized the "=head1" as starting a Pod block.
+
+=head2 Hints for Writing Pod
+
+=over
+
+=item *
+X<podchecker> X<POD, validating>
+
+The B<podchecker> command is provided for checking Pod syntax for errors
+and warnings. For example, it checks for completely blank lines in
+Pod blocks and for unknown commands and formatting codes. You should
+still also pass your document through one or more translators and proofread
+the result, or print out the result and proofread that. Some of the
+problems found may be bugs in the translators, which you may or may not
+wish to work around.
+
+=item *
+
+If you're more familiar with writing in HTML than with writing in Pod, you
+can try your hand at writing documentation in simple HTML, and converting
+it to Pod with the experimental L<Pod::HTML2Pod|Pod::HTML2Pod> module,
+(available in CPAN), and looking at the resulting code. The experimental
+L<Pod::PXML|Pod::PXML> module in CPAN might also be useful.
+
+=item *
+
+Many older Pod translators require the lines before every Pod
+command and after every Pod command (including "=cut"!) to be a blank
+line. Having something like this:
+
+ # - - - - - - - - - - - -
+ =item $firecracker->boom()
+
+ This noisily detonates the firecracker object.
+ =cut
+ sub boom {
+ ...
+
+...will make such Pod translators completely fail to see the Pod block
+at all.
+
+Instead, have it like this:
+
+ # - - - - - - - - - - - -
+
+ =item $firecracker->boom()
+
+ This noisily detonates the firecracker object.
+
+ =cut
+
+ sub boom {
+ ...
+
+=item *
+
+Some older Pod translators require paragraphs (including command
+paragraphs like "=head2 Functions") to be separated by I<completely>
+empty lines. If you have an apparently empty line with some spaces
+on it, this might not count as a separator for those translators, and
+that could cause odd formatting.
+
+=item *
+
+Older translators might add wording around an LE<lt>E<gt> link, so that
+C<LE<lt>Foo::BarE<gt>> may become "the Foo::Bar manpage", for example.
+So you shouldn't write things like C<the LE<lt>fooE<gt>
+documentation>, if you want the translated document to read sensibly.
+Instead, write C<the LE<lt>Foo::Bar|Foo::BarE<gt> documentation> or
+C<LE<lt>the Foo::Bar documentation|Foo::BarE<gt>>, to control how the
+link comes out.
+
+=item *
+
+Going past the 70th column in a verbatim block might be ungracefully
+wrapped by some formatters.
+
+=back
+
+=head1 SEE ALSO
+
+L<perlpodspec>, L<perlsyn/"PODs: Embedded Documentation">,
+L<perlnewmod>, L<perldoc>, L<pod2html>, L<pod2man>, L<podchecker>.
+
+=head1 AUTHOR
+
+Larry Wall, Sean M. Burke
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlpodspec.pod b/Master/tlpkg/tlperl/lib/pods/perlpodspec.pod
new file mode 100644
index 00000000000..0bf84e09104
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlpodspec.pod
@@ -0,0 +1,1923 @@
+
+=head1 NAME
+
+perlpodspec - Plain Old Documentation: format specification and notes
+
+=head1 DESCRIPTION
+
+This document is detailed notes on the Pod markup language. Most
+people will only have to read L<perlpod|perlpod> to know how to write
+in Pod, but this document may answer some incidental questions to do
+with parsing and rendering Pod.
+
+In this document, "must" / "must not", "should" /
+"should not", and "may" have their conventional (cf. RFC 2119)
+meanings: "X must do Y" means that if X doesn't do Y, it's against
+this specification, and should really be fixed. "X should do Y"
+means that it's recommended, but X may fail to do Y, if there's a
+good reason. "X may do Y" is merely a note that X can do Y at
+will (although it is up to the reader to detect any connotation of
+"and I think it would be I<nice> if X did Y" versus "it wouldn't
+really I<bother> me if X did Y").
+
+Notably, when I say "the parser should do Y", the
+parser may fail to do Y, if the calling application explicitly
+requests that the parser I<not> do Y. I often phrase this as
+"the parser should, by default, do Y." This doesn't I<require>
+the parser to provide an option for turning off whatever
+feature Y is (like expanding tabs in verbatim paragraphs), although
+it implicates that such an option I<may> be provided.
+
+=head1 Pod Definitions
+
+Pod is embedded in files, typically Perl source files, although you
+can write a file that's nothing but Pod.
+
+A B<line> in a file consists of zero or more non-newline characters,
+terminated by either a newline or the end of the file.
+
+A B<newline sequence> is usually a platform-dependent concept, but
+Pod parsers should understand it to mean any of CR (ASCII 13), LF
+(ASCII 10), or a CRLF (ASCII 13 followed immediately by ASCII 10), in
+addition to any other system-specific meaning. The first CR/CRLF/LF
+sequence in the file may be used as the basis for identifying the
+newline sequence for parsing the rest of the file.
+
+A B<blank line> is a line consisting entirely of zero or more spaces
+(ASCII 32) or tabs (ASCII 9), and terminated by a newline or end-of-file.
+A B<non-blank line> is a line containing one or more characters other
+than space or tab (and terminated by a newline or end-of-file).
+
+(I<Note:> Many older Pod parsers did not accept a line consisting of
+spaces/tabs and then a newline as a blank line. The only lines they
+considered blank were lines consisting of I<no characters at all>,
+terminated by a newline.)
+
+B<Whitespace> is used in this document as a blanket term for spaces,
+tabs, and newline sequences. (By itself, this term usually refers
+to literal whitespace. That is, sequences of whitespace characters
+in Pod source, as opposed to "EE<lt>32>", which is a formatting
+code that I<denotes> a whitespace character.)
+
+A B<Pod parser> is a module meant for parsing Pod (regardless of
+whether this involves calling callbacks or building a parse tree or
+directly formatting it). A B<Pod formatter> (or B<Pod translator>)
+is a module or program that converts Pod to some other format (HTML,
+plaintext, TeX, PostScript, RTF). A B<Pod processor> might be a
+formatter or translator, or might be a program that does something
+else with the Pod (like counting words, scanning for index points,
+etc.).
+
+Pod content is contained in B<Pod blocks>. A Pod block starts with a
+line that matches <m/\A=[a-zA-Z]/>, and continues up to the next line
+that matches C<m/\A=cut/> or up to the end of the file if there is
+no C<m/\A=cut/> line.
+
+=for comment
+ The current perlsyn says:
+ [beginquote]
+ Note that pod translators should look at only paragraphs beginning
+ with a pod directive (it makes parsing easier), whereas the compiler
+ actually knows to look for pod escapes even in the middle of a
+ paragraph. This means that the following secret stuff will be ignored
+ by both the compiler and the translators.
+ $a=3;
+ =secret stuff
+ warn "Neither POD nor CODE!?"
+ =cut back
+ print "got $a\n";
+ You probably shouldn't rely upon the warn() being podded out forever.
+ Not all pod translators are well-behaved in this regard, and perhaps
+ the compiler will become pickier.
+ [endquote]
+ I think that those paragraphs should just be removed; paragraph-based
+ parsing seems to have been largely abandoned, because of the hassle
+ with non-empty blank lines messing up what people meant by "paragraph".
+ Even if the "it makes parsing easier" bit were especially true,
+ it wouldn't be worth the confusion of having perl and pod2whatever
+ actually disagree on what can constitute a Pod block.
+
+Within a Pod block, there are B<Pod paragraphs>. A Pod paragraph
+consists of non-blank lines of text, separated by one or more blank
+lines.
+
+For purposes of Pod processing, there are four types of paragraphs in
+a Pod block:
+
+=over
+
+=item *
+
+A command paragraph (also called a "directive"). The first line of
+this paragraph must match C<m/\A=[a-zA-Z]/>. Command paragraphs are
+typically one line, as in:
+
+ =head1 NOTES
+
+ =item *
+
+But they may span several (non-blank) lines:
+
+ =for comment
+ Hm, I wonder what it would look like if
+ you tried to write a BNF for Pod from this.
+
+ =head3 Dr. Strangelove, or: How I Learned to
+ Stop Worrying and Love the Bomb
+
+I<Some> command paragraphs allow formatting codes in their content
+(i.e., after the part that matches C<m/\A=[a-zA-Z]\S*\s*/>), as in:
+
+ =head1 Did You Remember to C<use strict;>?
+
+In other words, the Pod processing handler for "head1" will apply the
+same processing to "Did You Remember to CE<lt>use strict;>?" that it
+would to an ordinary paragraph (i.e., formatting codes like
+"CE<lt>...>") are parsed and presumably formatted appropriately, and
+whitespace in the form of literal spaces and/or tabs is not
+significant.
+
+=item *
+
+A B<verbatim paragraph>. The first line of this paragraph must be a
+literal space or tab, and this paragraph must not be inside a "=begin
+I<identifier>", ... "=end I<identifier>" sequence unless
+"I<identifier>" begins with a colon (":"). That is, if a paragraph
+starts with a literal space or tab, but I<is> inside a
+"=begin I<identifier>", ... "=end I<identifier>" region, then it's
+a data paragraph, unless "I<identifier>" begins with a colon.
+
+Whitespace I<is> significant in verbatim paragraphs (although, in
+processing, tabs are probably expanded).
+
+=item *
+
+An B<ordinary paragraph>. A paragraph is an ordinary paragraph
+if its first line matches neither C<m/\A=[a-zA-Z]/> nor
+C<m/\A[ \t]/>, I<and> if it's not inside a "=begin I<identifier>",
+... "=end I<identifier>" sequence unless "I<identifier>" begins with
+a colon (":").
+
+=item *
+
+A B<data paragraph>. This is a paragraph that I<is> inside a "=begin
+I<identifier>" ... "=end I<identifier>" sequence where
+"I<identifier>" does I<not> begin with a literal colon (":"). In
+some sense, a data paragraph is not part of Pod at all (i.e.,
+effectively it's "out-of-band"), since it's not subject to most kinds
+of Pod parsing; but it is specified here, since Pod
+parsers need to be able to call an event for it, or store it in some
+form in a parse tree, or at least just parse I<around> it.
+
+=back
+
+For example: consider the following paragraphs:
+
+ # <- that's the 0th column
+
+ =head1 Foo
+
+ Stuff
+
+ $foo->bar
+
+ =cut
+
+Here, "=head1 Foo" and "=cut" are command paragraphs because the first
+line of each matches C<m/\A=[a-zA-Z]/>. "I<[space][space]>$foo->bar"
+is a verbatim paragraph, because its first line starts with a literal
+whitespace character (and there's no "=begin"..."=end" region around).
+
+The "=begin I<identifier>" ... "=end I<identifier>" commands stop
+paragraphs that they surround from being parsed as ordinary or verbatim
+paragraphs, if I<identifier> doesn't begin with a colon. This
+is discussed in detail in the section
+L</About Data Paragraphs and "=beginE<sol>=end" Regions>.
+
+=head1 Pod Commands
+
+This section is intended to supplement and clarify the discussion in
+L<perlpod/"Command Paragraph">. These are the currently recognized
+Pod commands:
+
+=over
+
+=item "=head1", "=head2", "=head3", "=head4"
+
+This command indicates that the text in the remainder of the paragraph
+is a heading. That text may contain formatting codes. Examples:
+
+ =head1 Object Attributes
+
+ =head3 What B<Not> to Do!
+
+=item "=pod"
+
+This command indicates that this paragraph begins a Pod block. (If we
+are already in the middle of a Pod block, this command has no effect at
+all.) If there is any text in this command paragraph after "=pod",
+it must be ignored. Examples:
+
+ =pod
+
+ This is a plain Pod paragraph.
+
+ =pod This text is ignored.
+
+=item "=cut"
+
+This command indicates that this line is the end of this previously
+started Pod block. If there is any text after "=cut" on the line, it must be
+ignored. Examples:
+
+ =cut
+
+ =cut The documentation ends here.
+
+ =cut
+ # This is the first line of program text.
+ sub foo { # This is the second.
+
+It is an error to try to I<start> a Pod block with a "=cut" command. In
+that case, the Pod processor must halt parsing of the input file, and
+must by default emit a warning.
+
+=item "=over"
+
+This command indicates that this is the start of a list/indent
+region. If there is any text following the "=over", it must consist
+of only a nonzero positive numeral. The semantics of this numeral is
+explained in the L</"About =over...=back Regions"> section, further
+below. Formatting codes are not expanded. Examples:
+
+ =over 3
+
+ =over 3.5
+
+ =over
+
+=item "=item"
+
+This command indicates that an item in a list begins here. Formatting
+codes are processed. The semantics of the (optional) text in the
+remainder of this paragraph are
+explained in the L</"About =over...=back Regions"> section, further
+below. Examples:
+
+ =item
+
+ =item *
+
+ =item *
+
+ =item 14
+
+ =item 3.
+
+ =item C<< $thing->stuff(I<dodad>) >>
+
+ =item For transporting us beyond seas to be tried for pretended
+ offenses
+
+ =item He is at this time transporting large armies of foreign
+ mercenaries to complete the works of death, desolation and
+ tyranny, already begun with circumstances of cruelty and perfidy
+ scarcely paralleled in the most barbarous ages, and totally
+ unworthy the head of a civilized nation.
+
+=item "=back"
+
+This command indicates that this is the end of the region begun
+by the most recent "=over" command. It permits no text after the
+"=back" command.
+
+=item "=begin formatname"
+
+=item "=begin formatname parameter"
+
+This marks the following paragraphs (until the matching "=end
+formatname") as being for some special kind of processing. Unless
+"formatname" begins with a colon, the contained non-command
+paragraphs are data paragraphs. But if "formatname" I<does> begin
+with a colon, then non-command paragraphs are ordinary paragraphs
+or data paragraphs. This is discussed in detail in the section
+L</About Data Paragraphs and "=beginE<sol>=end" Regions>.
+
+It is advised that formatnames match the regexp
+C<m/\A:?[−a−zA−Z0−9_]+\z/>. Everything following whitespace after the
+formatname is a parameter that may be used by the formatter when dealing
+with this region. This parameter must not be repeated in the "=end"
+paragraph. Implementors should anticipate future expansion in the
+semantics and syntax of the first parameter to "=begin"/"=end"/"=for".
+
+=item "=end formatname"
+
+This marks the end of the region opened by the matching
+"=begin formatname" region. If "formatname" is not the formatname
+of the most recent open "=begin formatname" region, then this
+is an error, and must generate an error message. This
+is discussed in detail in the section
+L</About Data Paragraphs and "=beginE<sol>=end" Regions>.
+
+=item "=for formatname text..."
+
+This is synonymous with:
+
+ =begin formatname
+
+ text...
+
+ =end formatname
+
+That is, it creates a region consisting of a single paragraph; that
+paragraph is to be treated as a normal paragraph if "formatname"
+begins with a ":"; if "formatname" I<doesn't> begin with a colon,
+then "text..." will constitute a data paragraph. There is no way
+to use "=for formatname text..." to express "text..." as a verbatim
+paragraph.
+
+=item "=encoding encodingname"
+
+This command, which should occur early in the document (at least
+before any non-US-ASCII data!), declares that this document is
+encoded in the encoding I<encodingname>, which must be
+an encoding name that L<Encode> recognizes. (Encode's list
+of supported encodings, in L<Encode::Supported>, is useful here.)
+If the Pod parser cannot decode the declared encoding, it
+should emit a warning and may abort parsing the document
+altogether.
+
+A document having more than one "=encoding" line should be
+considered an error. Pod processors may silently tolerate this if
+the not-first "=encoding" lines are just duplicates of the
+first one (e.g., if there's a "=encoding utf8" line, and later on
+another "=encoding utf8" line). But Pod processors should complain if
+there are contradictory "=encoding" lines in the same document
+(e.g., if there is a "=encoding utf8" early in the document and
+"=encoding big5" later). Pod processors that recognize BOMs
+may also complain if they see an "=encoding" line
+that contradicts the BOM (e.g., if a document with a UTF-16LE
+BOM has an "=encoding shiftjis" line).
+
+=back
+
+If a Pod processor sees any command other than the ones listed
+above (like "=head", or "=haed1", or "=stuff", or "=cuttlefish",
+or "=w123"), that processor must by default treat this as an
+error. It must not process the paragraph beginning with that
+command, must by default warn of this as an error, and may
+abort the parse. A Pod parser may allow a way for particular
+applications to add to the above list of known commands, and to
+stipulate, for each additional command, whether formatting
+codes should be processed.
+
+Future versions of this specification may add additional
+commands.
+
+
+
+=head1 Pod Formatting Codes
+
+(Note that in previous drafts of this document and of perlpod,
+formatting codes were referred to as "interior sequences", and
+this term may still be found in the documentation for Pod parsers,
+and in error messages from Pod processors.)
+
+There are two syntaxes for formatting codes:
+
+=over
+
+=item *
+
+A formatting code starts with a capital letter (just US-ASCII [A-Z])
+followed by a "<", any number of characters, and ending with the first
+matching ">". Examples:
+
+ That's what I<you> think!
+
+ What's C<dump()> for?
+
+ X<C<chmod> and C<unlink()> Under Different Operating Systems>
+
+=item *
+
+A formatting code starts with a capital letter (just US-ASCII [A-Z])
+followed by two or more "<"'s, one or more whitespace characters,
+any number of characters, one or more whitespace characters,
+and ending with the first matching sequence of two or more ">"'s, where
+the number of ">"'s equals the number of "<"'s in the opening of this
+formatting code. Examples:
+
+ That's what I<< you >> think!
+
+ C<<< open(X, ">>thing.dat") || die $! >>>
+
+ B<< $foo->bar(); >>
+
+With this syntax, the whitespace character(s) after the "CE<lt><<"
+and before the ">>" (or whatever letter) are I<not> renderable. They
+do not signify whitespace, are merely part of the formatting codes
+themselves. That is, these are all synonymous:
+
+ C<thing>
+ C<< thing >>
+ C<< thing >>
+ C<<< thing >>>
+ C<<<<
+ thing
+ >>>>
+
+and so on.
+
+Finally, the multiple-angle-bracket form does I<not> alter the interpretation
+of nested formatting codes, meaning that the following four example lines are
+identical in meaning:
+
+ B<example: C<$a E<lt>=E<gt> $b>>
+
+ B<example: C<< $a <=> $b >>>
+
+ B<example: C<< $a E<lt>=E<gt> $b >>>
+
+ B<<< example: C<< $a E<lt>=E<gt> $b >> >>>
+
+=back
+
+In parsing Pod, a notably tricky part is the correct parsing of
+(potentially nested!) formatting codes. Implementors should
+consult the code in the C<parse_text> routine in Pod::Parser as an
+example of a correct implementation.
+
+=over
+
+=item C<IE<lt>textE<gt>> -- italic text
+
+See the brief discussion in L<perlpod/"Formatting Codes">.
+
+=item C<BE<lt>textE<gt>> -- bold text
+
+See the brief discussion in L<perlpod/"Formatting Codes">.
+
+=item C<CE<lt>codeE<gt>> -- code text
+
+See the brief discussion in L<perlpod/"Formatting Codes">.
+
+=item C<FE<lt>filenameE<gt>> -- style for filenames
+
+See the brief discussion in L<perlpod/"Formatting Codes">.
+
+=item C<XE<lt>topic nameE<gt>> -- an index entry
+
+See the brief discussion in L<perlpod/"Formatting Codes">.
+
+This code is unusual in that most formatters completely discard
+this code and its content. Other formatters will render it with
+invisible codes that can be used in building an index of
+the current document.
+
+=item C<ZE<lt>E<gt>> -- a null (zero-effect) formatting code
+
+Discussed briefly in L<perlpod/"Formatting Codes">.
+
+This code is unusual is that it should have no content. That is,
+a processor may complain if it sees C<ZE<lt>potatoesE<gt>>. Whether
+or not it complains, the I<potatoes> text should ignored.
+
+=item C<LE<lt>nameE<gt>> -- a hyperlink
+
+The complicated syntaxes of this code are discussed at length in
+L<perlpod/"Formatting Codes">, and implementation details are
+discussed below, in L</"About LE<lt>...E<gt> Codes">. Parsing the
+contents of LE<lt>content> is tricky. Notably, the content has to be
+checked for whether it looks like a URL, or whether it has to be split
+on literal "|" and/or "/" (in the right order!), and so on,
+I<before> EE<lt>...> codes are resolved.
+
+=item C<EE<lt>escapeE<gt>> -- a character escape
+
+See L<perlpod/"Formatting Codes">, and several points in
+L</Notes on Implementing Pod Processors>.
+
+=item C<SE<lt>textE<gt>> -- text contains non-breaking spaces
+
+This formatting code is syntactically simple, but semantically
+complex. What it means is that each space in the printable
+content of this code signifies a non-breaking space.
+
+Consider:
+
+ C<$x ? $y : $z>
+
+ S<C<$x ? $y : $z>>
+
+Both signify the monospace (c[ode] style) text consisting of
+"$x", one space, "?", one space, ":", one space, "$z". The
+difference is that in the latter, with the S code, those spaces
+are not "normal" spaces, but instead are non-breaking spaces.
+
+=back
+
+
+If a Pod processor sees any formatting code other than the ones
+listed above (as in "NE<lt>...>", or "QE<lt>...>", etc.), that
+processor must by default treat this as an error.
+A Pod parser may allow a way for particular
+applications to add to the above list of known formatting codes;
+a Pod parser might even allow a way to stipulate, for each additional
+command, whether it requires some form of special processing, as
+LE<lt>...> does.
+
+Future versions of this specification may add additional
+formatting codes.
+
+Historical note: A few older Pod processors would not see a ">" as
+closing a "CE<lt>" code, if the ">" was immediately preceded by
+a "-". This was so that this:
+
+ C<$foo->bar>
+
+would parse as equivalent to this:
+
+ C<$foo-E<gt>bar>
+
+instead of as equivalent to a "C" formatting code containing
+only "$foo-", and then a "bar>" outside the "C" formatting code. This
+problem has since been solved by the addition of syntaxes like this:
+
+ C<< $foo->bar >>
+
+Compliant parsers must not treat "->" as special.
+
+Formatting codes absolutely cannot span paragraphs. If a code is
+opened in one paragraph, and no closing code is found by the end of
+that paragraph, the Pod parser must close that formatting code,
+and should complain (as in "Unterminated I code in the paragraph
+starting at line 123: 'Time objects are not...'"). So these
+two paragraphs:
+
+ I<I told you not to do this!
+
+ Don't make me say it again!>
+
+...must I<not> be parsed as two paragraphs in italics (with the I
+code starting in one paragraph and starting in another.) Instead,
+the first paragraph should generate a warning, but that aside, the
+above code must parse as if it were:
+
+ I<I told you not to do this!>
+
+ Don't make me say it again!E<gt>
+
+(In SGMLish jargon, all Pod commands are like block-level
+elements, whereas all Pod formatting codes are like inline-level
+elements.)
+
+
+
+=head1 Notes on Implementing Pod Processors
+
+The following is a long section of miscellaneous requirements
+and suggestions to do with Pod processing.
+
+=over
+
+=item *
+
+Pod formatters should tolerate lines in verbatim blocks that are of
+any length, even if that means having to break them (possibly several
+times, for very long lines) to avoid text running off the side of the
+page. Pod formatters may warn of such line-breaking. Such warnings
+are particularly appropriate for lines are over 100 characters long, which
+are usually not intentional.
+
+=item *
+
+Pod parsers must recognize I<all> of the three well-known newline
+formats: CR, LF, and CRLF. See L<perlport|perlport>.
+
+=item *
+
+Pod parsers should accept input lines that are of any length.
+
+=item *
+
+Since Perl recognizes a Unicode Byte Order Mark at the start of files
+as signaling that the file is Unicode encoded as in UTF-16 (whether
+big-endian or little-endian) or UTF-8, Pod parsers should do the
+same. Otherwise, the character encoding should be understood as
+being UTF-8 if the first highbit byte sequence in the file seems
+valid as a UTF-8 sequence, or otherwise as Latin-1.
+
+Future versions of this specification may specify
+how Pod can accept other encodings. Presumably treatment of other
+encodings in Pod parsing would be as in XML parsing: whatever the
+encoding declared by a particular Pod file, content is to be
+stored in memory as Unicode characters.
+
+=item *
+
+The well known Unicode Byte Order Marks are as follows: if the
+file begins with the two literal byte values 0xFE 0xFF, this is
+the BOM for big-endian UTF-16. If the file begins with the two
+literal byte value 0xFF 0xFE, this is the BOM for little-endian
+UTF-16. If the file begins with the three literal byte values
+0xEF 0xBB 0xBF, this is the BOM for UTF-8.
+
+=for comment
+ use bytes; print map sprintf(" 0x%02X", ord $_), split '', "\x{feff}";
+ 0xEF 0xBB 0xBF
+
+=for comment
+ If toke.c is modified to support UTF-32, add mention of those here.
+
+=item *
+
+A naive but sufficient heuristic for testing the first highbit
+byte-sequence in a BOM-less file (whether in code or in Pod!), to see
+whether that sequence is valid as UTF-8 (RFC 2279) is to check whether
+that the first byte in the sequence is in the range 0xC0 - 0xFD
+I<and> whether the next byte is in the range
+0x80 - 0xBF. If so, the parser may conclude that this file is in
+UTF-8, and all highbit sequences in the file should be assumed to
+be UTF-8. Otherwise the parser should treat the file as being
+in Latin-1. In the unlikely circumstance that the first highbit
+sequence in a truly non-UTF-8 file happens to appear to be UTF-8, one
+can cater to our heuristic (as well as any more intelligent heuristic)
+by prefacing that line with a comment line containing a highbit
+sequence that is clearly I<not> valid as UTF-8. A line consisting
+of simply "#", an e-acute, and any non-highbit byte,
+is sufficient to establish this file's encoding.
+
+=for comment
+ If/WHEN some brave soul makes these heuristics into a generic
+ text-file class (or PerlIO layer?), we can presumably delete
+ mention of these icky details from this file, and can instead
+ tell people to just use appropriate class/layer.
+ Auto-recognition of newline sequences would be another desirable
+ feature of such a class/layer.
+ HINT HINT HINT.
+
+=for comment
+ "The probability that a string of characters
+ in any other encoding appears as valid UTF-8 is low" - RFC2279
+
+=item *
+
+This document's requirements and suggestions about encodings
+do not apply to Pod processors running on non-ASCII platforms,
+notably EBCDIC platforms.
+
+=item *
+
+Pod processors must treat a "=for [label] [content...]" paragraph as
+meaning the same thing as a "=begin [label]" paragraph, content, and
+an "=end [label]" paragraph. (The parser may conflate these two
+constructs, or may leave them distinct, in the expectation that the
+formatter will nevertheless treat them the same.)
+
+=item *
+
+When rendering Pod to a format that allows comments (i.e., to nearly
+any format other than plaintext), a Pod formatter must insert comment
+text identifying its name and version number, and the name and
+version numbers of any modules it might be using to process the Pod.
+Minimal examples:
+
+ %% POD::Pod2PS v3.14159, using POD::Parser v1.92
+
+ <!-- Pod::HTML v3.14159, using POD::Parser v1.92 -->
+
+ {\doccomm generated by Pod::Tree::RTF 3.14159 using Pod::Tree 1.08}
+
+ .\" Pod::Man version 3.14159, using POD::Parser version 1.92
+
+Formatters may also insert additional comments, including: the
+release date of the Pod formatter program, the contact address for
+the author(s) of the formatter, the current time, the name of input
+file, the formatting options in effect, version of Perl used, etc.
+
+Formatters may also choose to note errors/warnings as comments,
+besides or instead of emitting them otherwise (as in messages to
+STDERR, or C<die>ing).
+
+=item *
+
+Pod parsers I<may> emit warnings or error messages ("Unknown E code
+EE<lt>zslig>!") to STDERR (whether through printing to STDERR, or
+C<warn>ing/C<carp>ing, or C<die>ing/C<croak>ing), but I<must> allow
+suppressing all such STDERR output, and instead allow an option for
+reporting errors/warnings
+in some other way, whether by triggering a callback, or noting errors
+in some attribute of the document object, or some similarly unobtrusive
+mechanism -- or even by appending a "Pod Errors" section to the end of
+the parsed form of the document.
+
+=item *
+
+In cases of exceptionally aberrant documents, Pod parsers may abort the
+parse. Even then, using C<die>ing/C<croak>ing is to be avoided; where
+possible, the parser library may simply close the input file
+and add text like "*** Formatting Aborted ***" to the end of the
+(partial) in-memory document.
+
+=item *
+
+In paragraphs where formatting codes (like EE<lt>...>, BE<lt>...>)
+are understood (i.e., I<not> verbatim paragraphs, but I<including>
+ordinary paragraphs, and command paragraphs that produce renderable
+text, like "=head1"), literal whitespace should generally be considered
+"insignificant", in that one literal space has the same meaning as any
+(nonzero) number of literal spaces, literal newlines, and literal tabs
+(as long as this produces no blank lines, since those would terminate
+the paragraph). Pod parsers should compact literal whitespace in each
+processed paragraph, but may provide an option for overriding this
+(since some processing tasks do not require it), or may follow
+additional special rules (for example, specially treating
+period-space-space or period-newline sequences).
+
+=item *
+
+Pod parsers should not, by default, try to coerce apostrophe (') and
+quote (") into smart quotes (little 9's, 66's, 99's, etc), nor try to
+turn backtick (`) into anything else but a single backtick character
+(distinct from an open quote character!), nor "--" into anything but
+two minus signs. They I<must never> do any of those things to text
+in CE<lt>...> formatting codes, and never I<ever> to text in verbatim
+paragraphs.
+
+=item *
+
+When rendering Pod to a format that has two kinds of hyphens (-), one
+that's a non-breaking hyphen, and another that's a breakable hyphen
+(as in "object-oriented", which can be split across lines as
+"object-", newline, "oriented"), formatters are encouraged to
+generally translate "-" to non-breaking hyphen, but may apply
+heuristics to convert some of these to breaking hyphens.
+
+=item *
+
+Pod formatters should make reasonable efforts to keep words of Perl
+code from being broken across lines. For example, "Foo::Bar" in some
+formatting systems is seen as eligible for being broken across lines
+as "Foo::" newline "Bar" or even "Foo::-" newline "Bar". This should
+be avoided where possible, either by disabling all line-breaking in
+mid-word, or by wrapping particular words with internal punctuation
+in "don't break this across lines" codes (which in some formats may
+not be a single code, but might be a matter of inserting non-breaking
+zero-width spaces between every pair of characters in a word.)
+
+=item *
+
+Pod parsers should, by default, expand tabs in verbatim paragraphs as
+they are processed, before passing them to the formatter or other
+processor. Parsers may also allow an option for overriding this.
+
+=item *
+
+Pod parsers should, by default, remove newlines from the end of
+ordinary and verbatim paragraphs before passing them to the
+formatter. For example, while the paragraph you're reading now
+could be considered, in Pod source, to end with (and contain)
+the newline(s) that end it, it should be processed as ending with
+(and containing) the period character that ends this sentence.
+
+=item *
+
+Pod parsers, when reporting errors, should make some effort to report
+an approximate line number ("Nested EE<lt>>'s in Paragraph #52, near
+line 633 of Thing/Foo.pm!"), instead of merely noting the paragraph
+number ("Nested EE<lt>>'s in Paragraph #52 of Thing/Foo.pm!"). Where
+this is problematic, the paragraph number should at least be
+accompanied by an excerpt from the paragraph ("Nested EE<lt>>'s in
+Paragraph #52 of Thing/Foo.pm, which begins 'Read/write accessor for
+the CE<lt>interest rate> attribute...'").
+
+=item *
+
+Pod parsers, when processing a series of verbatim paragraphs one
+after another, should consider them to be one large verbatim
+paragraph that happens to contain blank lines. I.e., these two
+lines, which have a blank line between them:
+
+ use Foo;
+
+ print Foo->VERSION
+
+should be unified into one paragraph ("\tuse Foo;\n\n\tprint
+Foo->VERSION") before being passed to the formatter or other
+processor. Parsers may also allow an option for overriding this.
+
+While this might be too cumbersome to implement in event-based Pod
+parsers, it is straightforward for parsers that return parse trees.
+
+=item *
+
+Pod formatters, where feasible, are advised to avoid splitting short
+verbatim paragraphs (under twelve lines, say) across pages.
+
+=item *
+
+Pod parsers must treat a line with only spaces and/or tabs on it as a
+"blank line" such as separates paragraphs. (Some older parsers
+recognized only two adjacent newlines as a "blank line" but would not
+recognize a newline, a space, and a newline, as a blank line. This
+is noncompliant behavior.)
+
+=item *
+
+Authors of Pod formatters/processors should make every effort to
+avoid writing their own Pod parser. There are already several in
+CPAN, with a wide range of interface styles -- and one of them,
+Pod::Parser, comes with modern versions of Perl.
+
+=item *
+
+Characters in Pod documents may be conveyed either as literals, or by
+number in EE<lt>n> codes, or by an equivalent mnemonic, as in
+EE<lt>eacute> which is exactly equivalent to EE<lt>233>.
+
+Characters in the range 32-126 refer to those well known US-ASCII
+characters (also defined there by Unicode, with the same meaning),
+which all Pod formatters must render faithfully. Characters
+in the ranges 0-31 and 127-159 should not be used (neither as
+literals, nor as EE<lt>number> codes), except for the
+literal byte-sequences for newline (13, 13 10, or 10), and tab (9).
+
+Characters in the range 160-255 refer to Latin-1 characters (also
+defined there by Unicode, with the same meaning). Characters above
+255 should be understood to refer to Unicode characters.
+
+=item *
+
+Be warned
+that some formatters cannot reliably render characters outside 32-126;
+and many are able to handle 32-126 and 160-255, but nothing above
+255.
+
+=item *
+
+Besides the well-known "EE<lt>lt>" and "EE<lt>gt>" codes for
+less-than and greater-than, Pod parsers must understand "EE<lt>sol>"
+for "/" (solidus, slash), and "EE<lt>verbar>" for "|" (vertical bar,
+pipe). Pod parsers should also understand "EE<lt>lchevron>" and
+"EE<lt>rchevron>" as legacy codes for characters 171 and 187, i.e.,
+"left-pointing double angle quotation mark" = "left pointing
+guillemet" and "right-pointing double angle quotation mark" = "right
+pointing guillemet". (These look like little "<<" and ">>", and they
+are now preferably expressed with the HTML/XHTML codes "EE<lt>laquo>"
+and "EE<lt>raquo>".)
+
+=item *
+
+Pod parsers should understand all "EE<lt>html>" codes as defined
+in the entity declarations in the most recent XHTML specification at
+C<www.W3.org>. Pod parsers must understand at least the entities
+that define characters in the range 160-255 (Latin-1). Pod parsers,
+when faced with some unknown "EE<lt>I<identifier>>" code,
+shouldn't simply replace it with nullstring (by default, at least),
+but may pass it through as a string consisting of the literal characters
+E, less-than, I<identifier>, greater-than. Or Pod parsers may offer the
+alternative option of processing such unknown
+"EE<lt>I<identifier>>" codes by firing an event especially
+for such codes, or by adding a special node-type to the in-memory
+document tree. Such "EE<lt>I<identifier>>" may have special meaning
+to some processors, or some processors may choose to add them to
+a special error report.
+
+=item *
+
+Pod parsers must also support the XHTML codes "EE<lt>quot>" for
+character 34 (doublequote, "), "EE<lt>amp>" for character 38
+(ampersand, &), and "EE<lt>apos>" for character 39 (apostrophe, ').
+
+=item *
+
+Note that in all cases of "EE<lt>whatever>", I<whatever> (whether
+an htmlname, or a number in any base) must consist only of
+alphanumeric characters -- that is, I<whatever> must watch
+C<m/\A\w+\z/>. So "EE<lt> 0 1 2 3 >" is invalid, because
+it contains spaces, which aren't alphanumeric characters. This
+presumably does not I<need> special treatment by a Pod processor;
+" 0 1 2 3 " doesn't look like a number in any base, so it would
+presumably be looked up in the table of HTML-like names. Since
+there isn't (and cannot be) an HTML-like entity called " 0 1 2 3 ",
+this will be treated as an error. However, Pod processors may
+treat "EE<lt> 0 1 2 3 >" or "EE<lt>e-acute>" as I<syntactically>
+invalid, potentially earning a different error message than the
+error message (or warning, or event) generated by a merely unknown
+(but theoretically valid) htmlname, as in "EE<lt>qacute>"
+[sic]. However, Pod parsers are not required to make this
+distinction.
+
+=item *
+
+Note that EE<lt>number> I<must not> be interpreted as simply
+"codepoint I<number> in the current/native character set". It always
+means only "the character represented by codepoint I<number> in
+Unicode." (This is identical to the semantics of &#I<number>; in XML.)
+
+This will likely require many formatters to have tables mapping from
+treatable Unicode codepoints (such as the "\xE9" for the e-acute
+character) to the escape sequences or codes necessary for conveying
+such sequences in the target output format. A converter to *roff
+would, for example know that "\xE9" (whether conveyed literally, or via
+a EE<lt>...> sequence) is to be conveyed as "e\\*'".
+Similarly, a program rendering Pod in a Mac OS application window, would
+presumably need to know that "\xE9" maps to codepoint 142 in MacRoman
+encoding that (at time of writing) is native for Mac OS. Such
+Unicode2whatever mappings are presumably already widely available for
+common output formats. (Such mappings may be incomplete! Implementers
+are not expected to bend over backwards in an attempt to render
+Cherokee syllabics, Etruscan runes, Byzantine musical symbols, or any
+of the other weird things that Unicode can encode.) And
+if a Pod document uses a character not found in such a mapping, the
+formatter should consider it an unrenderable character.
+
+=item *
+
+If, surprisingly, the implementor of a Pod formatter can't find a
+satisfactory pre-existing table mapping from Unicode characters to
+escapes in the target format (e.g., a decent table of Unicode
+characters to *roff escapes), it will be necessary to build such a
+table. If you are in this circumstance, you should begin with the
+characters in the range 0x00A0 - 0x00FF, which is mostly the heavily
+used accented characters. Then proceed (as patience permits and
+fastidiousness compels) through the characters that the (X)HTML
+standards groups judged important enough to merit mnemonics
+for. These are declared in the (X)HTML specifications at the
+www.W3.org site. At time of writing (September 2001), the most recent
+entity declaration files are:
+
+ http://www.w3.org/TR/xhtml1/DTD/xhtml-lat1.ent
+ http://www.w3.org/TR/xhtml1/DTD/xhtml-special.ent
+ http://www.w3.org/TR/xhtml1/DTD/xhtml-symbol.ent
+
+Then you can progress through any remaining notable Unicode characters
+in the range 0x2000-0x204D (consult the character tables at
+www.unicode.org), and whatever else strikes your fancy. For example,
+in F<xhtml-symbol.ent>, there is the entry:
+
+ <!ENTITY infin "&#8734;"> <!-- infinity, U+221E ISOtech -->
+
+While the mapping "infin" to the character "\x{221E}" will (hopefully)
+have been already handled by the Pod parser, the presence of the
+character in this file means that it's reasonably important enough to
+include in a formatter's table that maps from notable Unicode characters
+to the codes necessary for rendering them. So for a Unicode-to-*roff
+mapping, for example, this would merit the entry:
+
+ "\x{221E}" => '\(in',
+
+It is eagerly hoped that in the future, increasing numbers of formats
+(and formatters) will support Unicode characters directly (as (X)HTML
+does with C<&infin;>, C<&#8734;>, or C<&#x221E;>), reducing the need
+for idiosyncratic mappings of Unicode-to-I<my_escapes>.
+
+=item *
+
+It is up to individual Pod formatter to display good judgement when
+confronted with an unrenderable character (which is distinct from an
+unknown EE<lt>thing> sequence that the parser couldn't resolve to
+anything, renderable or not). It is good practice to map Latin letters
+with diacritics (like "EE<lt>eacute>"/"EE<lt>233>") to the corresponding
+unaccented US-ASCII letters (like a simple character 101, "e"), but
+clearly this is often not feasible, and an unrenderable character may
+be represented as "?", or the like. In attempting a sane fallback
+(as from EE<lt>233> to "e"), Pod formatters may use the
+%Latin1Code_to_fallback table in L<Pod::Escapes|Pod::Escapes>, or
+L<Text::Unidecode|Text::Unidecode>, if available.
+
+For example, this Pod text:
+
+ magic is enabled if you set C<$Currency> to 'E<euro>'.
+
+may be rendered as:
+"magic is enabled if you set C<$Currency> to 'I<?>'" or as
+"magic is enabled if you set C<$Currency> to 'B<[euro]>'", or as
+"magic is enabled if you set C<$Currency> to '[x20AC]', etc.
+
+A Pod formatter may also note, in a comment or warning, a list of what
+unrenderable characters were encountered.
+
+=item *
+
+EE<lt>...> may freely appear in any formatting code (other than
+in another EE<lt>...> or in an ZE<lt>>). That is, "XE<lt>The
+EE<lt>euro>1,000,000 Solution>" is valid, as is "LE<lt>The
+EE<lt>euro>1,000,000 Solution|Million::Euros>".
+
+=item *
+
+Some Pod formatters output to formats that implement non-breaking
+spaces as an individual character (which I'll call "NBSP"), and
+others output to formats that implement non-breaking spaces just as
+spaces wrapped in a "don't break this across lines" code. Note that
+at the level of Pod, both sorts of codes can occur: Pod can contain a
+NBSP character (whether as a literal, or as a "EE<lt>160>" or
+"EE<lt>nbsp>" code); and Pod can contain "SE<lt>foo
+IE<lt>barE<gt> baz>" codes, where "mere spaces" (character 32) in
+such codes are taken to represent non-breaking spaces. Pod
+parsers should consider supporting the optional parsing of "SE<lt>foo
+IE<lt>barE<gt> baz>" as if it were
+"fooI<NBSP>IE<lt>barE<gt>I<NBSP>baz", and, going the other way, the
+optional parsing of groups of words joined by NBSP's as if each group
+were in a SE<lt>...> code, so that formatters may use the
+representation that maps best to what the output format demands.
+
+=item *
+
+Some processors may find that the C<SE<lt>...E<gt>> code is easiest to
+implement by replacing each space in the parse tree under the content
+of the S, with an NBSP. But note: the replacement should apply I<not> to
+spaces in I<all> text, but I<only> to spaces in I<printable> text. (This
+distinction may or may not be evident in the particular tree/event
+model implemented by the Pod parser.) For example, consider this
+unusual case:
+
+ S<L</Autoloaded Functions>>
+
+This means that the space in the middle of the visible link text must
+not be broken across lines. In other words, it's the same as this:
+
+ L<"AutoloadedE<160>Functions"/Autoloaded Functions>
+
+However, a misapplied space-to-NBSP replacement could (wrongly)
+produce something equivalent to this:
+
+ L<"AutoloadedE<160>Functions"/AutoloadedE<160>Functions>
+
+...which is almost definitely not going to work as a hyperlink (assuming
+this formatter outputs a format supporting hypertext).
+
+Formatters may choose to just not support the S format code,
+especially in cases where the output format simply has no NBSP
+character/code and no code for "don't break this stuff across lines".
+
+=item *
+
+Besides the NBSP character discussed above, implementors are reminded
+of the existence of the other "special" character in Latin-1, the
+"soft hyphen" character, also known as "discretionary hyphen",
+i.e. C<EE<lt>173E<gt>> = C<EE<lt>0xADE<gt>> =
+C<EE<lt>shyE<gt>>). This character expresses an optional hyphenation
+point. That is, it normally renders as nothing, but may render as a
+"-" if a formatter breaks the word at that point. Pod formatters
+should, as appropriate, do one of the following: 1) render this with
+a code with the same meaning (e.g., "\-" in RTF), 2) pass it through
+in the expectation that the formatter understands this character as
+such, or 3) delete it.
+
+For example:
+
+ sigE<shy>action
+ manuE<shy>script
+ JarkE<shy>ko HieE<shy>taE<shy>nieE<shy>mi
+
+These signal to a formatter that if it is to hyphenate "sigaction"
+or "manuscript", then it should be done as
+"sig-I<[linebreak]>action" or "manu-I<[linebreak]>script"
+(and if it doesn't hyphenate it, then the C<EE<lt>shyE<gt>> doesn't
+show up at all). And if it is
+to hyphenate "Jarkko" and/or "Hietaniemi", it can do
+so only at the points where there is a C<EE<lt>shyE<gt>> code.
+
+In practice, it is anticipated that this character will not be used
+often, but formatters should either support it, or delete it.
+
+=item *
+
+If you think that you want to add a new command to Pod (like, say, a
+"=biblio" command), consider whether you could get the same
+effect with a for or begin/end sequence: "=for biblio ..." or "=begin
+biblio" ... "=end biblio". Pod processors that don't understand
+"=for biblio", etc, will simply ignore it, whereas they may complain
+loudly if they see "=biblio".
+
+=item *
+
+Throughout this document, "Pod" has been the preferred spelling for
+the name of the documentation format. One may also use "POD" or
+"pod". For the documentation that is (typically) in the Pod
+format, you may use "pod", or "Pod", or "POD". Understanding these
+distinctions is useful; but obsessing over how to spell them, usually
+is not.
+
+=back
+
+
+
+
+
+=head1 About LE<lt>...E<gt> Codes
+
+As you can tell from a glance at L<perlpod|perlpod>, the LE<lt>...>
+code is the most complex of the Pod formatting codes. The points below
+will hopefully clarify what it means and how processors should deal
+with it.
+
+=over
+
+=item *
+
+In parsing an LE<lt>...> code, Pod parsers must distinguish at least
+four attributes:
+
+=over
+
+=item First:
+
+The link-text. If there is none, this must be undef. (E.g., in
+"LE<lt>Perl Functions|perlfunc>", the link-text is "Perl Functions".
+In "LE<lt>Time::HiRes>" and even "LE<lt>|Time::HiRes>", there is no
+link text. Note that link text may contain formatting.)
+
+=item Second:
+
+The possibly inferred link-text; i.e., if there was no real link
+text, then this is the text that we'll infer in its place. (E.g., for
+"LE<lt>Getopt::Std>", the inferred link text is "Getopt::Std".)
+
+=item Third:
+
+The name or URL, or undef if none. (E.g., in "LE<lt>Perl
+Functions|perlfunc>", the name (also sometimes called the page)
+is "perlfunc". In "LE<lt>/CAVEATS>", the name is undef.)
+
+=item Fourth:
+
+The section (AKA "item" in older perlpods), or undef if none. E.g.,
+in "LE<lt>Getopt::Std/DESCRIPTIONE<gt>", "DESCRIPTION" is the section. (Note
+that this is not the same as a manpage section like the "5" in "man 5
+crontab". "Section Foo" in the Pod sense means the part of the text
+that's introduced by the heading or item whose text is "Foo".)
+
+=back
+
+Pod parsers may also note additional attributes including:
+
+=over
+
+=item Fifth:
+
+A flag for whether item 3 (if present) is a URL (like
+"http://lists.perl.org" is), in which case there should be no section
+attribute; a Pod name (like "perldoc" and "Getopt::Std" are); or
+possibly a man page name (like "crontab(5)" is).
+
+=item Sixth:
+
+The raw original LE<lt>...> content, before text is split on
+"|", "/", etc, and before EE<lt>...> codes are expanded.
+
+=back
+
+(The above were numbered only for concise reference below. It is not
+a requirement that these be passed as an actual list or array.)
+
+For example:
+
+ L<Foo::Bar>
+ => undef, # link text
+ "Foo::Bar", # possibly inferred link text
+ "Foo::Bar", # name
+ undef, # section
+ 'pod', # what sort of link
+ "Foo::Bar" # original content
+
+ L<Perlport's section on NL's|perlport/Newlines>
+ => "Perlport's section on NL's", # link text
+ "Perlport's section on NL's", # possibly inferred link text
+ "perlport", # name
+ "Newlines", # section
+ 'pod', # what sort of link
+ "Perlport's section on NL's|perlport/Newlines" # orig. content
+
+ L<perlport/Newlines>
+ => undef, # link text
+ '"Newlines" in perlport', # possibly inferred link text
+ "perlport", # name
+ "Newlines", # section
+ 'pod', # what sort of link
+ "perlport/Newlines" # original content
+
+ L<crontab(5)/"DESCRIPTION">
+ => undef, # link text
+ '"DESCRIPTION" in crontab(5)', # possibly inferred link text
+ "crontab(5)", # name
+ "DESCRIPTION", # section
+ 'man', # what sort of link
+ 'crontab(5)/"DESCRIPTION"' # original content
+
+ L</Object Attributes>
+ => undef, # link text
+ '"Object Attributes"', # possibly inferred link text
+ undef, # name
+ "Object Attributes", # section
+ 'pod', # what sort of link
+ "/Object Attributes" # original content
+
+ L<http://www.perl.org/>
+ => undef, # link text
+ "http://www.perl.org/", # possibly inferred link text
+ "http://www.perl.org/", # name
+ undef, # section
+ 'url', # what sort of link
+ "http://www.perl.org/" # original content
+
+ L<Perl.org|http://www.perl.org/>
+ => "Perl.org", # link text
+ "http://www.perl.org/", # possibly inferred link text
+ "http://www.perl.org/", # name
+ undef, # section
+ 'url', # what sort of link
+ "Perl.org|http://www.perl.org/" # original content
+
+Note that you can distinguish URL-links from anything else by the
+fact that they match C<m/\A\w+:[^:\s]\S*\z/>. So
+C<LE<lt>http://www.perl.comE<gt>> is a URL, but
+C<LE<lt>HTTP::ResponseE<gt>> isn't.
+
+=item *
+
+In case of LE<lt>...> codes with no "text|" part in them,
+older formatters have exhibited great variation in actually displaying
+the link or cross reference. For example, LE<lt>crontab(5)> would render
+as "the C<crontab(5)> manpage", or "in the C<crontab(5)> manpage"
+or just "C<crontab(5)>".
+
+Pod processors must now treat "text|"-less links as follows:
+
+ L<name> => L<name|name>
+ L</section> => L<"section"|/section>
+ L<name/section> => L<"section" in name|name/section>
+
+=item *
+
+Note that section names might contain markup. I.e., if a section
+starts with:
+
+ =head2 About the C<-M> Operator
+
+or with:
+
+ =item About the C<-M> Operator
+
+then a link to it would look like this:
+
+ L<somedoc/About the C<-M> Operator>
+
+Formatters may choose to ignore the markup for purposes of resolving
+the link and use only the renderable characters in the section name,
+as in:
+
+ <h1><a name="About_the_-M_Operator">About the <code>-M</code>
+ Operator</h1>
+
+ ...
+
+ <a href="somedoc#About_the_-M_Operator">About the <code>-M</code>
+ Operator" in somedoc</a>
+
+=item *
+
+Previous versions of perlpod distinguished C<LE<lt>name/"section"E<gt>>
+links from C<LE<lt>name/itemE<gt>> links (and their targets). These
+have been merged syntactically and semantically in the current
+specification, and I<section> can refer either to a "=headI<n> Heading
+Content" command or to a "=item Item Content" command. This
+specification does not specify what behavior should be in the case
+of a given document having several things all seeming to produce the
+same I<section> identifier (e.g., in HTML, several things all producing
+the same I<anchorname> in <a name="I<anchorname>">...</a>
+elements). Where Pod processors can control this behavior, they should
+use the first such anchor. That is, C<LE<lt>Foo/BarE<gt>> refers to the
+I<first> "Bar" section in Foo.
+
+But for some processors/formats this cannot be easily controlled; as
+with the HTML example, the behavior of multiple ambiguous
+<a name="I<anchorname>">...</a> is most easily just left up to
+browsers to decide.
+
+=item *
+
+Authors wanting to link to a particular (absolute) URL, must do so
+only with "LE<lt>scheme:...>" codes (like
+LE<lt>http://www.perl.org>), and must not attempt "LE<lt>Some Site
+Name|scheme:...>" codes. This restriction avoids many problems
+in parsing and rendering LE<lt>...> codes.
+
+=item *
+
+In a C<LE<lt>text|...E<gt>> code, text may contain formatting codes
+for formatting or for EE<lt>...> escapes, as in:
+
+ L<B<ummE<234>stuff>|...>
+
+For C<LE<lt>...E<gt>> codes without a "name|" part, only
+C<EE<lt>...E<gt>> and C<ZE<lt>E<gt>> codes may occur. That is,
+authors should not use "C<LE<lt>BE<lt>Foo::BarE<gt>E<gt>>".
+
+Note, however, that formatting codes and ZE<lt>>'s can occur in any
+and all parts of an LE<lt>...> (i.e., in I<name>, I<section>, I<text>,
+and I<url>).
+
+Authors must not nest LE<lt>...> codes. For example, "LE<lt>The
+LE<lt>Foo::Bar> man page>" should be treated as an error.
+
+=item *
+
+Note that Pod authors may use formatting codes inside the "text"
+part of "LE<lt>text|name>" (and so on for LE<lt>text|/"sec">).
+
+In other words, this is valid:
+
+ Go read L<the docs on C<$.>|perlvar/"$.">
+
+Some output formats that do allow rendering "LE<lt>...>" codes as
+hypertext, might not allow the link-text to be formatted; in
+that case, formatters will have to just ignore that formatting.
+
+=item *
+
+At time of writing, C<LE<lt>nameE<gt>> values are of two types:
+either the name of a Pod page like C<LE<lt>Foo::BarE<gt>> (which
+might be a real Perl module or program in an @INC / PATH
+directory, or a .pod file in those places); or the name of a Unix
+man page, like C<LE<lt>crontab(5)E<gt>>. In theory, C<LE<lt>chmodE<gt>>
+in ambiguous between a Pod page called "chmod", or the Unix man page
+"chmod" (in whatever man-section). However, the presence of a string
+in parens, as in "crontab(5)", is sufficient to signal that what
+is being discussed is not a Pod page, and so is presumably a
+Unix man page. The distinction is of no importance to many
+Pod processors, but some processors that render to hypertext formats
+may need to distinguish them in order to know how to render a
+given C<LE<lt>fooE<gt>> code.
+
+=item *
+
+Previous versions of perlpod allowed for a C<LE<lt>sectionE<gt>> syntax (as in
+C<LE<lt>Object AttributesE<gt>>), which was not easily distinguishable from
+C<LE<lt>nameE<gt>> syntax and for C<LE<lt>"section"E<gt>> which was only
+slightly less ambiguous. This syntax is no longer in the specification, and
+has been replaced by the C<LE<lt>/sectionE<gt>> syntax (where the slash was
+formerly optional). Pod parsers should tolerate the C<LE<lt>"section"E<gt>>
+syntax, for a while at least. The suggested heuristic for distinguishing
+C<LE<lt>sectionE<gt>> from C<LE<lt>nameE<gt>> is that if it contains any
+whitespace, it's a I<section>. Pod processors should warn about this being
+deprecated syntax.
+
+=back
+
+=head1 About =over...=back Regions
+
+"=over"..."=back" regions are used for various kinds of list-like
+structures. (I use the term "region" here simply as a collective
+term for everything from the "=over" to the matching "=back".)
+
+=over
+
+=item *
+
+The non-zero numeric I<indentlevel> in "=over I<indentlevel>" ...
+"=back" is used for giving the formatter a clue as to how many
+"spaces" (ems, or roughly equivalent units) it should tab over,
+although many formatters will have to convert this to an absolute
+measurement that may not exactly match with the size of spaces (or M's)
+in the document's base font. Other formatters may have to completely
+ignore the number. The lack of any explicit I<indentlevel> parameter is
+equivalent to an I<indentlevel> value of 4. Pod processors may
+complain if I<indentlevel> is present but is not a positive number
+matching C<m/\A(\d*\.)?\d+\z/>.
+
+=item *
+
+Authors of Pod formatters are reminded that "=over" ... "=back" may
+map to several different constructs in your output format. For
+example, in converting Pod to (X)HTML, it can map to any of
+<ul>...</ul>, <ol>...</ol>, <dl>...</dl>, or
+<blockquote>...</blockquote>. Similarly, "=item" can map to <li> or
+<dt>.
+
+=item *
+
+Each "=over" ... "=back" region should be one of the following:
+
+=over
+
+=item *
+
+An "=over" ... "=back" region containing only "=item *" commands,
+each followed by some number of ordinary/verbatim paragraphs, other
+nested "=over" ... "=back" regions, "=for..." paragraphs, and
+"=begin"..."=end" regions.
+
+(Pod processors must tolerate a bare "=item" as if it were "=item
+*".) Whether "*" is rendered as a literal asterisk, an "o", or as
+some kind of real bullet character, is left up to the Pod formatter,
+and may depend on the level of nesting.
+
+=item *
+
+An "=over" ... "=back" region containing only
+C<m/\A=item\s+\d+\.?\s*\z/> paragraphs, each one (or each group of them)
+followed by some number of ordinary/verbatim paragraphs, other nested
+"=over" ... "=back" regions, "=for..." paragraphs, and/or
+"=begin"..."=end" codes. Note that the numbers must start at 1
+in each section, and must proceed in order and without skipping
+numbers.
+
+(Pod processors must tolerate lines like "=item 1" as if they were
+"=item 1.", with the period.)
+
+=item *
+
+An "=over" ... "=back" region containing only "=item [text]"
+commands, each one (or each group of them) followed by some number of
+ordinary/verbatim paragraphs, other nested "=over" ... "=back"
+regions, or "=for..." paragraphs, and "=begin"..."=end" regions.
+
+The "=item [text]" paragraph should not match
+C<m/\A=item\s+\d+\.?\s*\z/> or C<m/\A=item\s+\*\s*\z/>, nor should it
+match just C<m/\A=item\s*\z/>.
+
+=item *
+
+An "=over" ... "=back" region containing no "=item" paragraphs at
+all, and containing only some number of
+ordinary/verbatim paragraphs, and possibly also some nested "=over"
+... "=back" regions, "=for..." paragraphs, and "=begin"..."=end"
+regions. Such an itemless "=over" ... "=back" region in Pod is
+equivalent in meaning to a "<blockquote>...</blockquote>" element in
+HTML.
+
+=back
+
+Note that with all the above cases, you can determine which type of
+"=over" ... "=back" you have, by examining the first (non-"=cut",
+non-"=pod") Pod paragraph after the "=over" command.
+
+=item *
+
+Pod formatters I<must> tolerate arbitrarily large amounts of text
+in the "=item I<text...>" paragraph. In practice, most such
+paragraphs are short, as in:
+
+ =item For cutting off our trade with all parts of the world
+
+But they may be arbitrarily long:
+
+ =item For transporting us beyond seas to be tried for pretended
+ offenses
+
+ =item He is at this time transporting large armies of foreign
+ mercenaries to complete the works of death, desolation and
+ tyranny, already begun with circumstances of cruelty and perfidy
+ scarcely paralleled in the most barbarous ages, and totally
+ unworthy the head of a civilized nation.
+
+=item *
+
+Pod processors should tolerate "=item *" / "=item I<number>" commands
+with no accompanying paragraph. The middle item is an example:
+
+ =over
+
+ =item 1
+
+ Pick up dry cleaning.
+
+ =item 2
+
+ =item 3
+
+ Stop by the store. Get Abba Zabas, Stoli, and cheap lawn chairs.
+
+ =back
+
+=item *
+
+No "=over" ... "=back" region can contain headings. Processors may
+treat such a heading as an error.
+
+=item *
+
+Note that an "=over" ... "=back" region should have some
+content. That is, authors should not have an empty region like this:
+
+ =over
+
+ =back
+
+Pod processors seeing such a contentless "=over" ... "=back" region,
+may ignore it, or may report it as an error.
+
+=item *
+
+Processors must tolerate an "=over" list that goes off the end of the
+document (i.e., which has no matching "=back"), but they may warn
+about such a list.
+
+=item *
+
+Authors of Pod formatters should note that this construct:
+
+ =item Neque
+
+ =item Porro
+
+ =item Quisquam Est
+
+ Qui dolorem ipsum quia dolor sit amet, consectetur, adipisci
+ velit, sed quia non numquam eius modi tempora incidunt ut
+ labore et dolore magnam aliquam quaerat voluptatem.
+
+ =item Ut Enim
+
+is semantically ambiguous, in a way that makes formatting decisions
+a bit difficult. On the one hand, it could be mention of an item
+"Neque", mention of another item "Porro", and mention of another
+item "Quisquam Est", with just the last one requiring the explanatory
+paragraph "Qui dolorem ipsum quia dolor..."; and then an item
+"Ut Enim". In that case, you'd want to format it like so:
+
+ Neque
+
+ Porro
+
+ Quisquam Est
+ Qui dolorem ipsum quia dolor sit amet, consectetur, adipisci
+ velit, sed quia non numquam eius modi tempora incidunt ut
+ labore et dolore magnam aliquam quaerat voluptatem.
+
+ Ut Enim
+
+But it could equally well be a discussion of three (related or equivalent)
+items, "Neque", "Porro", and "Quisquam Est", followed by a paragraph
+explaining them all, and then a new item "Ut Enim". In that case, you'd
+probably want to format it like so:
+
+ Neque
+ Porro
+ Quisquam Est
+ Qui dolorem ipsum quia dolor sit amet, consectetur, adipisci
+ velit, sed quia non numquam eius modi tempora incidunt ut
+ labore et dolore magnam aliquam quaerat voluptatem.
+
+ Ut Enim
+
+But (for the foreseeable future), Pod does not provide any way for Pod
+authors to distinguish which grouping is meant by the above
+"=item"-cluster structure. So formatters should format it like so:
+
+ Neque
+
+ Porro
+
+ Quisquam Est
+
+ Qui dolorem ipsum quia dolor sit amet, consectetur, adipisci
+ velit, sed quia non numquam eius modi tempora incidunt ut
+ labore et dolore magnam aliquam quaerat voluptatem.
+
+ Ut Enim
+
+That is, there should be (at least roughly) equal spacing between
+items as between paragraphs (although that spacing may well be less
+than the full height of a line of text). This leaves it to the reader
+to use (con)textual cues to figure out whether the "Qui dolorem
+ipsum..." paragraph applies to the "Quisquam Est" item or to all three
+items "Neque", "Porro", and "Quisquam Est". While not an ideal
+situation, this is preferable to providing formatting cues that may
+be actually contrary to the author's intent.
+
+=back
+
+
+
+=head1 About Data Paragraphs and "=begin/=end" Regions
+
+Data paragraphs are typically used for inlining non-Pod data that is
+to be used (typically passed through) when rendering the document to
+a specific format:
+
+ =begin rtf
+
+ \par{\pard\qr\sa4500{\i Printed\~\chdate\~\chtime}\par}
+
+ =end rtf
+
+The exact same effect could, incidentally, be achieved with a single
+"=for" paragraph:
+
+ =for rtf \par{\pard\qr\sa4500{\i Printed\~\chdate\~\chtime}\par}
+
+(Although that is not formally a data paragraph, it has the same
+meaning as one, and Pod parsers may parse it as one.)
+
+Another example of a data paragraph:
+
+ =begin html
+
+ I like <em>PIE</em>!
+
+ <hr>Especially pecan pie!
+
+ =end html
+
+If these were ordinary paragraphs, the Pod parser would try to
+expand the "EE<lt>/em>" (in the first paragraph) as a formatting
+code, just like "EE<lt>lt>" or "EE<lt>eacute>". But since this
+is in a "=begin I<identifier>"..."=end I<identifier>" region I<and>
+the identifier "html" doesn't begin have a ":" prefix, the contents
+of this region are stored as data paragraphs, instead of being
+processed as ordinary paragraphs (or if they began with a spaces
+and/or tabs, as verbatim paragraphs).
+
+As a further example: At time of writing, no "biblio" identifier is
+supported, but suppose some processor were written to recognize it as
+a way of (say) denoting a bibliographic reference (necessarily
+containing formatting codes in ordinary paragraphs). The fact that
+"biblio" paragraphs were meant for ordinary processing would be
+indicated by prefacing each "biblio" identifier with a colon:
+
+ =begin :biblio
+
+ Wirth, Niklaus. 1976. I<Algorithms + Data Structures =
+ Programs.> Prentice-Hall, Englewood Cliffs, NJ.
+
+ =end :biblio
+
+This would signal to the parser that paragraphs in this begin...end
+region are subject to normal handling as ordinary/verbatim paragraphs
+(while still tagged as meant only for processors that understand the
+"biblio" identifier). The same effect could be had with:
+
+ =for :biblio
+ Wirth, Niklaus. 1976. I<Algorithms + Data Structures =
+ Programs.> Prentice-Hall, Englewood Cliffs, NJ.
+
+The ":" on these identifiers means simply "process this stuff
+normally, even though the result will be for some special target".
+I suggest that parser APIs report "biblio" as the target identifier,
+but also report that it had a ":" prefix. (And similarly, with the
+above "html", report "html" as the target identifier, and note the
+I<lack> of a ":" prefix.)
+
+Note that a "=begin I<identifier>"..."=end I<identifier>" region where
+I<identifier> begins with a colon, I<can> contain commands. For example:
+
+ =begin :biblio
+
+ Wirth's classic is available in several editions, including:
+
+ =for comment
+ hm, check abebooks.com for how much used copies cost.
+
+ =over
+
+ =item
+
+ Wirth, Niklaus. 1975. I<Algorithmen und Datenstrukturen.>
+ Teubner, Stuttgart. [Yes, it's in German.]
+
+ =item
+
+ Wirth, Niklaus. 1976. I<Algorithms + Data Structures =
+ Programs.> Prentice-Hall, Englewood Cliffs, NJ.
+
+ =back
+
+ =end :biblio
+
+Note, however, a "=begin I<identifier>"..."=end I<identifier>"
+region where I<identifier> does I<not> begin with a colon, should not
+directly contain "=head1" ... "=head4" commands, nor "=over", nor "=back",
+nor "=item". For example, this may be considered invalid:
+
+ =begin somedata
+
+ This is a data paragraph.
+
+ =head1 Don't do this!
+
+ This is a data paragraph too.
+
+ =end somedata
+
+A Pod processor may signal that the above (specifically the "=head1"
+paragraph) is an error. Note, however, that the following should
+I<not> be treated as an error:
+
+ =begin somedata
+
+ This is a data paragraph.
+
+ =cut
+
+ # Yup, this isn't Pod anymore.
+ sub excl { (rand() > .5) ? "hoo!" : "hah!" }
+
+ =pod
+
+ This is a data paragraph too.
+
+ =end somedata
+
+And this too is valid:
+
+ =begin someformat
+
+ This is a data paragraph.
+
+ And this is a data paragraph.
+
+ =begin someotherformat
+
+ This is a data paragraph too.
+
+ And this is a data paragraph too.
+
+ =begin :yetanotherformat
+
+ =head2 This is a command paragraph!
+
+ This is an ordinary paragraph!
+
+ And this is a verbatim paragraph!
+
+ =end :yetanotherformat
+
+ =end someotherformat
+
+ Another data paragraph!
+
+ =end someformat
+
+The contents of the above "=begin :yetanotherformat" ...
+"=end :yetanotherformat" region I<aren't> data paragraphs, because
+the immediately containing region's identifier (":yetanotherformat")
+begins with a colon. In practice, most regions that contain
+data paragraphs will contain I<only> data paragraphs; however,
+the above nesting is syntactically valid as Pod, even if it is
+rare. However, the handlers for some formats, like "html",
+will accept only data paragraphs, not nested regions; and they may
+complain if they see (targeted for them) nested regions, or commands,
+other than "=end", "=pod", and "=cut".
+
+Also consider this valid structure:
+
+ =begin :biblio
+
+ Wirth's classic is available in several editions, including:
+
+ =over
+
+ =item
+
+ Wirth, Niklaus. 1975. I<Algorithmen und Datenstrukturen.>
+ Teubner, Stuttgart. [Yes, it's in German.]
+
+ =item
+
+ Wirth, Niklaus. 1976. I<Algorithms + Data Structures =
+ Programs.> Prentice-Hall, Englewood Cliffs, NJ.
+
+ =back
+
+ Buy buy buy!
+
+ =begin html
+
+ <img src='wirth_spokesmodeling_book.png'>
+
+ <hr>
+
+ =end html
+
+ Now now now!
+
+ =end :biblio
+
+There, the "=begin html"..."=end html" region is nested inside
+the larger "=begin :biblio"..."=end :biblio" region. Note that the
+content of the "=begin html"..."=end html" region is data
+paragraph(s), because the immediately containing region's identifier
+("html") I<doesn't> begin with a colon.
+
+Pod parsers, when processing a series of data paragraphs one
+after another (within a single region), should consider them to
+be one large data paragraph that happens to contain blank lines. So
+the content of the above "=begin html"..."=end html" I<may> be stored
+as two data paragraphs (one consisting of
+"<img src='wirth_spokesmodeling_book.png'>\n"
+and another consisting of "<hr>\n"), but I<should> be stored as
+a single data paragraph (consisting of
+"<img src='wirth_spokesmodeling_book.png'>\n\n<hr>\n").
+
+Pod processors should tolerate empty
+"=begin I<something>"..."=end I<something>" regions,
+empty "=begin :I<something>"..."=end :I<something>" regions, and
+contentless "=for I<something>" and "=for :I<something>"
+paragraphs. I.e., these should be tolerated:
+
+ =for html
+
+ =begin html
+
+ =end html
+
+ =begin :biblio
+
+ =end :biblio
+
+Incidentally, note that there's no easy way to express a data
+paragraph starting with something that looks like a command. Consider:
+
+ =begin stuff
+
+ =shazbot
+
+ =end stuff
+
+There, "=shazbot" will be parsed as a Pod command "shazbot", not as a data
+paragraph "=shazbot\n". However, you can express a data paragraph consisting
+of "=shazbot\n" using this code:
+
+ =for stuff =shazbot
+
+The situation where this is necessary, is presumably quite rare.
+
+Note that =end commands must match the currently open =begin command. That
+is, they must properly nest. For example, this is valid:
+
+ =begin outer
+
+ X
+
+ =begin inner
+
+ Y
+
+ =end inner
+
+ Z
+
+ =end outer
+
+while this is invalid:
+
+ =begin outer
+
+ X
+
+ =begin inner
+
+ Y
+
+ =end outer
+
+ Z
+
+ =end inner
+
+This latter is improper because when the "=end outer" command is seen, the
+currently open region has the formatname "inner", not "outer". (It just
+happens that "outer" is the format name of a higher-up region.) This is
+an error. Processors must by default report this as an error, and may halt
+processing the document containing that error. A corollary of this is that
+regions cannot "overlap". That is, the latter block above does not represent
+a region called "outer" which contains X and Y, overlapping a region called
+"inner" which contains Y and Z. But because it is invalid (as all
+apparently overlapping regions would be), it doesn't represent that, or
+anything at all.
+
+Similarly, this is invalid:
+
+ =begin thing
+
+ =end hting
+
+This is an error because the region is opened by "thing", and the "=end"
+tries to close "hting" [sic].
+
+This is also invalid:
+
+ =begin thing
+
+ =end
+
+This is invalid because every "=end" command must have a formatname
+parameter.
+
+=head1 SEE ALSO
+
+L<perlpod>, L<perlsyn/"PODs: Embedded Documentation">,
+L<podchecker>
+
+=head1 AUTHOR
+
+Sean M. Burke
+
+=cut
+
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlpolicy.pod b/Master/tlpkg/tlperl/lib/pods/perlpolicy.pod
new file mode 100644
index 00000000000..5b078781588
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlpolicy.pod
@@ -0,0 +1,376 @@
+=head1 NAME
+
+perlpolicy - Various and sundry policies and commitments related to the perl core
+
+=head1 DESCRIPTION
+
+This document is the master document which records all written
+policies about how the Perl 5 Porters collectively develop and maintain
+the Perl core.
+
+=head1 MAINTENANCE AND SUPPORT
+
+Perl 5 is developed by a community, not a corporate entity. Every change
+contributed to the Perl core is the result of a donation. Typically, these
+donations are contributions of code or time by individual members of our
+community. On occasion, these donations come in the form of corporate
+or organizational sponsorship of a particular individual or project.
+
+As a volunteer organization, the commitments we make are heavily dependent
+on the goodwill and hard work of individuals who have no obligation to
+contribute to Perl.
+
+That being said, we value Perl's stabilty and security and have long
+had an unwritten covenant with the broader Perl community to support
+and maintain releases of Perl.
+
+This document codifies the support and maintenance commitments that
+the Perl community should expect from Perl's developers:
+
+=over
+
+=item *
+
+We "officially" support the two most recent stable release
+series'. As of the release of 5.14.0, we will "officially"
+end support for Perl 5.10, other than providing security
+updates as described below.
+
+=item *
+
+To the best of our ability, we will attempt to fix critical issues
+in the two most recent stable 5.x release series'. Fixes for the
+current release series take precedence over fixes for the previous
+release series.
+
+=item *
+
+To the best of our ability, we will provide "critical" security patches
+/ releases for any major version of Perl initially released within the
+past three years. We can only commit to providing these for the most
+recent .y release in any 5.x.y series.
+
+=item *
+
+We will not provide security updates or bug fixes for development
+releases of Perl.
+
+=item *
+
+We encourage vendors to ship the most recent supported release of
+Perl at the time of their code freeze.
+
+=item *
+
+As a vendor, you may have a requirement to backport security fixes
+beyond our 3 year support commitment. We can provide limited support and
+advice to you as you do so and, where possible will try to apply
+those patches to the relevant -maint branches in git, though we may or
+may not choose to make numbered releases or "official" patches
+available. Contact us at E<lt>perl5-security-report@perl.orgE<gt>
+to begin that process.
+
+=back
+
+=head1 BACKWARD COMPATIBILITY AND DEPRECATION
+
+Our community has a long-held belief that backward-compatibility is a
+virtue, even when the functionality in question is a design flaw.
+
+We would all love to unmake some mistakes we've made over the past
+decades. Living with every design error we've ever made can lead
+to painful stagnation. Unwinding our mistakes is very, very
+difficult. Doing so without actively harming our users is
+nearly impossible.
+
+Lately, ignoring or actively opposing compatibility with earlier versions
+of Perl has come into vogue. Sometimes, a change is proposed which
+wants to usurp syntax which previously had another meaning. Sometimes,
+a change wants to improve previously-crazy semantics.
+
+Down this road lies madness.
+
+Requiring end-user programmers to change just a few language constructs,
+even language constructs which no well-educated developer would ever
+intentionally use is tantamount to saying "you should not upgrade to
+a new release of Perl unless you have 100% test coverage and can do a
+full manual audit of your codebase." If we were to have tools capable of
+reliably upgrading Perl source code from one version of Perl to another,
+this concern could be significantly mitigated.
+
+We want to ensure that Perl continues to grow and flourish in the coming
+years and decades, but not at the expense of our user community.
+
+Existing syntax and semantics should only be marked for destruction in
+very limited circumstances. If a given language feature's continued
+inclusion in the language will cause significant harm to the language
+or prevent us from making needed changes to the runtime, then it may
+be considered for deprecation.
+
+Any language change which breaks backward-compatibility should be able to
+be enabled or disabled lexically. Unless code at a given scope declares
+that it wants the new behavior, that new behavior should be disabled.
+Which backward-incompatible changes are controlled implicitly by a
+'use v5.x.y' is a decision which should be made by the pumpking in
+consultation with the community.
+
+When a backward-incompatible change can't be toggled lexically, the decision
+to change the language must be considered very, very carefully. If it's
+possible to move the old syntax or semantics out of the core language
+and into XS-land, that XS module should be enabled by default unless
+the user declares that they want a newer revision of Perl.
+
+Historically, we've held ourselves to a far higher standard than
+backward-compatibility -- bugward-compatibility. Any accident of
+implementation or unintentional side-effect of running some bit of code
+has been considered to be a feature of the language to be defended with
+the same zeal as any other feature or functionality. No matter how
+frustrating these unintentional features may be to us as we continue
+to improve Perl, these unintentional features often deserve our
+protection. It is very important that existing software written in
+Perl continue to work correctly. If end-user developers have adopted a
+bug as a feature, we need to treat it as such.
+
+New syntax and semantics which don't break existing language constructs
+and syntax have a much lower bar. They merely need to prove themselves
+to be useful, elegant, well designed and well tested.
+
+=head2 Terminology
+
+To make sure we're talking about the same thing when we discuss the removal
+of features or functionality from the Perl core, we have specific definitions
+for a few words and phrases.
+
+=over
+
+=item experimental
+
+If something in the Perl core is marked as B<experimental>, we may change
+its behaviour, deprecate or remove it without notice. While we'll always
+do our best to smooth the transition path for users of experimental
+features, you should contact the perl5-porters mailinglist if you find
+an experimental feature useful and want to help shape its future.
+
+=item deprecated
+
+If something in the Perl core is marked as B<deprecated>, we may remove it
+from thecore in the next stable release series, though we may not. As of
+Perl 5.12, deprecated features and modules warn the user as they're used.
+If you use a deprecated feature and believe that its removal from the Perl
+core would be a mistake, please contact the perl5-porters mailinglist and
+plead your case. We don't deprecate things without a good reason, but
+sometimes there's a counterargument we haven't considered. Historically,
+we did not distinguish between "deprecated" and "discouraged" features.
+
+=item discouraged
+
+From time to time, we may mark language constructs and features which we
+consider to have been mistakes as B<discouraged>. Discouraged features
+aren't candidates for removal in the next major release series, but
+we may later deprecate them if they're found to stand in the way of a
+significant improvement to the core.
+
+=item removed
+
+Once a feature, construct or module has been marked as deprecated for a
+stable release cycle, we may remove it from the core. Unsurprisingly,
+we say we've B<removed> these things.
+
+=back
+
+=head1 MAINTENANCE BRANCHES
+
+=over
+
+=item *
+
+New releases of maint should contain as few changes as possible.
+If there is any question about whether a given patch might merit
+inclusion in a maint release, then it almost certainly should not
+be included.
+
+=item *
+
+Portability fixes, such as changes to Configure and the files in
+hints/ are acceptable. Ports of Perl to a new platform, architecture
+or OS release that involve changes to the implementation are NOT
+acceptable.
+
+=item *
+
+Documentation updates are acceptable.
+
+=item *
+
+Patches that add new warnings or errors or deprecate features
+are not acceptable.
+
+=item *
+
+Patches that fix crashing bugs that do not otherwise change Perl's
+functionality or negatively impact performance are acceptable.
+
+=item *
+
+Patches that fix CVEs or security issues are acceptable, but should
+be run through the perl5-security-report@perl.org mailing list
+rather than applied directly.
+
+=item *
+
+Updates to dual-life modules should consist of minimal patches to
+fix crashing or security issues (as above).
+
+=item *
+
+New versions of dual-life modules should NOT be imported into maint.
+Those belong in the next stable series.
+
+=item *
+
+Patches that add or remove features are not acceptable.
+
+=item *
+
+Patches that break binary compatibility are not acceptable. (Please
+talk to a pumpking.)
+
+=back
+
+
+=head2 Getting changes into a maint branch
+
+Historically, only the pumpking cherry-picked changes from bleadperl
+into maintperl. This has...scaling problems. At the same time,
+maintenance branches of stable versions of Perl need to be treated with
+great care. To that end, we're going to try out a new process for
+maint-5.12.
+
+Any committer may cherry-pick any commit from blead to maint-5.12 if
+they send mail to perl5-porters announcing their intent to cherry-pick
+a specific commit along with a rationale for doing so and at least two
+other committers respond to the list giving their assent. (This policy
+applies to current and former pumpkings, as well as other committers.)
+
+=head1 CONTRIBUTED MODULES
+
+
+=head2 A Social Contract about Artistic Control
+
+What follows is a statement about artistic control, defined as the ability
+of authors of packages to guide the future of their code and maintain
+control over their work. It is a recognition that authors should have
+control over their work, and that it is a responsibility of the rest of
+the Perl community to ensure that they retain this control. It is an
+attempt to document the standards to which we, as Perl developers, intend
+to hold ourselves. It is an attempt to write down rough guidelines about
+the respect we owe each other as Perl developers.
+
+This statement is not a legal contract. This statement is not a legal
+document in any way, shape, or form. Perl is distributed under the GNU
+Public License and under the Artistic License; those are the precise legal
+terms. This statement isn't about the law or licenses. It's about
+community, mutual respect, trust, and good-faith cooperation.
+
+We recognize that the Perl core, defined as the software distributed with
+the heart of Perl itself, is a joint project on the part of all of us.
+From time to time, a script, module, or set of modules (hereafter referred
+to simply as a "module") will prove so widely useful and/or so integral to
+the correct functioning of Perl itself that it should be distributed with
+Perl core. This should never be done without the author's explicit
+consent, and a clear recognition on all parts that this means the module
+is being distributed under the same terms as Perl itself. A module author
+should realize that inclusion of a module into the Perl core will
+necessarily mean some loss of control over it, since changes may
+occasionally have to be made on short notice or for consistency with the
+rest of Perl.
+
+Once a module has been included in the Perl core, however, everyone
+involved in maintaining Perl should be aware that the module is still the
+property of the original author unless the original author explicitly
+gives up their ownership of it. In particular:
+
+=over
+
+=item *
+
+The version of the module in the core should still be considered the
+work of the original author. All patches, bug reports, and so
+forth should be fed back to them. Their development directions
+should be respected whenever possible.
+
+=item *
+
+Patches may be applied by the pumpkin holder without the explicit
+cooperation of the module author if and only if they are very minor,
+time-critical in some fashion (such as urgent security fixes), or if
+the module author cannot be reached. Those patches must still be
+given back to the author when possible, and if the author decides on
+an alternate fix in their version, that fix should be strongly
+preferred unless there is a serious problem with it. Any changes not
+endorsed by the author should be marked as such, and the contributor
+of the change acknowledged.
+
+=item *
+
+The version of the module distributed with Perl should, whenever
+possible, be the latest version of the module as distributed by the
+author (the latest non-beta version in the case of public Perl
+releases), although the pumpkin holder may hold off on upgrading the
+version of the module distributed with Perl to the latest version
+until the latest version has had sufficient testing.
+
+=back
+
+In other words, the author of a module should be considered to have final
+say on modifications to their module whenever possible (bearing in mind
+that it's expected that everyone involved will work together and arrive at
+reasonable compromises when there are disagreements).
+
+As a last resort, however:
+
+
+If the author's vision of the future of their module is sufficiently
+different from the vision of the pumpkin holder and perl5-porters as a
+whole so as to cause serious problems for Perl, the pumpkin holder may
+choose to formally fork the version of the module in the core from the
+one maintained by the author. This should not be done lightly and
+should B<always> if at all possible be done only after direct input
+from Larry. If this is done, it must then be made explicit in the
+module as distributed with Perl core that it is a forked version and
+that while it is based on the original author's work, it is no longer
+maintained by them. This must be noted in both the documentation and
+in the comments in the source of the module.
+
+Again, this should be a last resort only. Ideally, this should never
+happen, and every possible effort at cooperation and compromise should be
+made before doing this. If it does prove necessary to fork a module for
+the overall health of Perl, proper credit must be given to the original
+author in perpetuity and the decision should be constantly re-evaluated to
+see if a remerging of the two branches is possible down the road.
+
+In all dealings with contributed modules, everyone maintaining Perl should
+keep in mind that the code belongs to the original author, that they may
+not be on perl5-porters at any given time, and that a patch is not
+official unless it has been integrated into the author's copy of the
+module. To aid with this, and with points #1, #2, and #3 above, contact
+information for the authors of all contributed modules should be kept with
+the Perl distribution.
+
+Finally, the Perl community as a whole recognizes that respect for
+ownership of code, respect for artistic control, proper credit, and active
+effort to prevent unintentional code skew or communication gaps is vital
+to the health of the community and Perl itself. Members of a community
+should not normally have to resort to rules and laws to deal with each
+other, and this document, although it contains rules so as to be clear, is
+about an attitude and general approach. The first step in any dispute
+should be open communication, respect for opposing views, and an attempt
+at a compromise. In nearly every circumstance nothing more will be
+necessary, and certainly no more drastic measure should be used until
+every avenue of communication and discussion has failed.
+
+
+=head1 CREDITS
+
+Social Contract about Contributed Modules originally by Russ Allbery E<lt>rra@stanford.eduE<gt> and the perl5-porters.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlport.pod b/Master/tlpkg/tlperl/lib/pods/perlport.pod
new file mode 100644
index 00000000000..9c81e73e445
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlport.pod
@@ -0,0 +1,2345 @@
+=head1 NAME
+
+perlport - Writing portable Perl
+
+=head1 DESCRIPTION
+
+Perl runs on numerous operating systems. While most of them share
+much in common, they also have their own unique features.
+
+This document is meant to help you to find out what constitutes portable
+Perl code. That way once you make a decision to write portably,
+you know where the lines are drawn, and you can stay within them.
+
+There is a tradeoff between taking full advantage of one particular
+type of computer and taking advantage of a full range of them.
+Naturally, as you broaden your range and become more diverse, the
+common factors drop, and you are left with an increasingly smaller
+area of common ground in which you can operate to accomplish a
+particular task. Thus, when you begin attacking a problem, it is
+important to consider under which part of the tradeoff curve you
+want to operate. Specifically, you must decide whether it is
+important that the task that you are coding have the full generality
+of being portable, or whether to just get the job done right now.
+This is the hardest choice to be made. The rest is easy, because
+Perl provides many choices, whichever way you want to approach your
+problem.
+
+Looking at it another way, writing portable code is usually about
+willfully limiting your available choices. Naturally, it takes
+discipline and sacrifice to do that. The product of portability
+and convenience may be a constant. You have been warned.
+
+Be aware of two important points:
+
+=over 4
+
+=item Not all Perl programs have to be portable
+
+There is no reason you should not use Perl as a language to glue Unix
+tools together, or to prototype a Macintosh application, or to manage the
+Windows registry. If it makes no sense to aim for portability for one
+reason or another in a given program, then don't bother.
+
+=item Nearly all of Perl already I<is> portable
+
+Don't be fooled into thinking that it is hard to create portable Perl
+code. It isn't. Perl tries its level-best to bridge the gaps between
+what's available on different platforms, and all the means available to
+use those features. Thus almost all Perl code runs on any machine
+without modification. But there are some significant issues in
+writing portable code, and this document is entirely about those issues.
+
+=back
+
+Here's the general rule: When you approach a task commonly done
+using a whole range of platforms, think about writing portable
+code. That way, you don't sacrifice much by way of the implementation
+choices you can avail yourself of, and at the same time you can give
+your users lots of platform choices. On the other hand, when you have to
+take advantage of some unique feature of a particular platform, as is
+often the case with systems programming (whether for Unix, Windows,
+VMS, etc.), consider writing platform-specific code.
+
+When the code will run on only two or three operating systems, you
+may need to consider only the differences of those particular systems.
+The important thing is to decide where the code will run and to be
+deliberate in your decision.
+
+The material below is separated into three main sections: main issues of
+portability (L<"ISSUES">), platform-specific issues (L<"PLATFORMS">), and
+built-in perl functions that behave differently on various ports
+(L<"FUNCTION IMPLEMENTATIONS">).
+
+This information should not be considered complete; it includes possibly
+transient information about idiosyncrasies of some of the ports, almost
+all of which are in a state of constant evolution. Thus, this material
+should be considered a perpetual work in progress
+(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
+
+=head1 ISSUES
+
+=head2 Newlines
+
+In most operating systems, lines in files are terminated by newlines.
+Just what is used as a newline may vary from OS to OS. Unix
+traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
+and S<Mac OS> uses C<\015>.
+
+Perl uses C<\n> to represent the "logical" newline, where what is
+logical may depend on the platform in use. In MacPerl, C<\n> always
+means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but when
+accessing a file in "text" mode, perl uses the C<:crlf> layer that
+translates it to (or from) C<\015\012>, depending on whether you're
+reading or writing. Unix does the same thing on ttys in canonical
+mode. C<\015\012> is commonly referred to as CRLF.
+
+To trim trailing newlines from text lines use chomp(). With default
+settings that function looks for a trailing C<\n> character and thus
+trims in a portable way.
+
+When dealing with binary files (or text files in binary mode) be sure
+to explicitly set $/ to the appropriate value for your file format
+before using chomp().
+
+Because of the "text" mode translation, DOSish perls have limitations
+in using C<seek> and C<tell> on a file accessed in "text" mode.
+Stick to C<seek>-ing to locations you got from C<tell> (and no
+others), and you are usually free to use C<seek> and C<tell> even
+in "text" mode. Using C<seek> or C<tell> or other file operations
+may be non-portable. If you use C<binmode> on a file, however, you
+can usually C<seek> and C<tell> with arbitrary values in safety.
+
+A common misconception in socket programming is that C<\n> eq C<\012>
+everywhere. When using protocols such as common Internet protocols,
+C<\012> and C<\015> are called for specifically, and the values of
+the logical C<\n> and C<\r> (carriage return) are not reliable.
+
+ print SOCKET "Hi there, client!\r\n"; # WRONG
+ print SOCKET "Hi there, client!\015\012"; # RIGHT
+
+However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
+and unsightly, as well as confusing to those maintaining the code. As
+such, the Socket module supplies the Right Thing for those who want it.
+
+ use Socket qw(:DEFAULT :crlf);
+ print SOCKET "Hi there, client!$CRLF" # RIGHT
+
+When reading from a socket, remember that the default input record
+separator C<$/> is C<\n>, but robust socket code will recognize as
+either C<\012> or C<\015\012> as end of line:
+
+ while (<SOCKET>) {
+ # ...
+ }
+
+Because both CRLF and LF end in LF, the input record separator can
+be set to LF and any CR stripped later. Better to write:
+
+ use Socket qw(:DEFAULT :crlf);
+ local($/) = LF; # not needed if $/ is already \012
+
+ while (<SOCKET>) {
+ s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
+ # s/\015?\012/\n/; # same thing
+ }
+
+This example is preferred over the previous one--even for Unix
+platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
+(and there was much rejoicing).
+
+Similarly, functions that return text data--such as a function that
+fetches a web page--should sometimes translate newlines before
+returning the data, if they've not yet been translated to the local
+newline representation. A single line of code will often suffice:
+
+ $data =~ s/\015?\012/\n/g;
+ return $data;
+
+Some of this may be confusing. Here's a handy reference to the ASCII CR
+and LF characters. You can print it out and stick it in your wallet.
+
+ LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
+
+ | Unix | DOS | Mac |
+ ---------------------------
+ \n | LF | LF | CR |
+ \r | CR | CR | LF |
+ \n * | LF | CRLF | CR |
+ \r * | CR | CR | LF |
+ ---------------------------
+ * text-mode STDIO
+
+The Unix column assumes that you are not accessing a serial line
+(like a tty) in canonical mode. If you are, then CR on input becomes
+"\n", and "\n" on output becomes CRLF.
+
+These are just the most common definitions of C<\n> and C<\r> in Perl.
+There may well be others. For example, on an EBCDIC implementation
+such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
+the above material is similar to "Unix" but the code numbers change:
+
+ LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
+ LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
+ CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
+
+ | z/OS | OS/400 |
+ ----------------------
+ \n | LF | LF |
+ \r | CR | CR |
+ \n * | LF | LF |
+ \r * | CR | CR |
+ ----------------------
+ * text-mode STDIO
+
+=head2 Numbers endianness and Width
+
+Different CPUs store integers and floating point numbers in different
+orders (called I<endianness>) and widths (32-bit and 64-bit being the
+most common today). This affects your programs when they attempt to transfer
+numbers in binary format from one CPU architecture to another,
+usually either "live" via network connection, or by storing the
+numbers to secondary storage such as a disk file or tape.
+
+Conflicting storage orders make utter mess out of the numbers. If a
+little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
+decimal), a big-endian host (Motorola, Sparc, PA) reads it as
+0x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
+Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
+them in big-endian mode. To avoid this problem in network (socket)
+connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
+"network" orders. These are guaranteed to be portable.
+
+As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
+to force big- or little-endian byte-order. This is useful if you want
+to store signed integers or 64-bit integers, for example.
+
+You can explore the endianness of your platform by unpacking a
+data structure packed in native format such as:
+
+ print unpack("h*", pack("s2", 1, 2)), "\n";
+ # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
+ # '00100020' on e.g. Motorola 68040
+
+If you need to distinguish between endian architectures you could use
+either of the variables set like so:
+
+ $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
+ $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
+
+Differing widths can cause truncation even between platforms of equal
+endianness. The platform of shorter width loses the upper parts of the
+number. There is no good solution for this problem except to avoid
+transferring or storing raw binary numbers.
+
+One can circumnavigate both these problems in two ways. Either
+transfer and store numbers always in text format, instead of raw
+binary, or else consider using modules like Data::Dumper (included in
+the standard distribution as of Perl 5.005) and Storable (included as
+of perl 5.8). Keeping all data as text significantly simplifies matters.
+
+The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
+how far EBCDIC, or more precisely UTF-EBCDIC will go.
+
+=head2 Files and Filesystems
+
+Most platforms these days structure files in a hierarchical fashion.
+So, it is reasonably safe to assume that all platforms support the
+notion of a "path" to uniquely identify a file on the system. How
+that path is really written, though, differs considerably.
+
+Although similar, file path specifications differ between Unix,
+Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
+Unix, for example, is one of the few OSes that has the elegant idea
+of a single root directory.
+
+DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
+as path separator, or in their own idiosyncratic ways (such as having
+several root directories and various "unrooted" device files such NIL:
+and LPT:).
+
+S<Mac OS> 9 and earlier used C<:> as a path separator instead of C</>.
+
+The filesystem may support neither hard links (C<link>) nor
+symbolic links (C<symlink>, C<readlink>, C<lstat>).
+
+The filesystem may support neither access timestamp nor change
+timestamp (meaning that about the only portable timestamp is the
+modification timestamp), or one second granularity of any timestamps
+(e.g. the FAT filesystem limits the time granularity to two seconds).
+
+The "inode change timestamp" (the C<-C> filetest) may really be the
+"creation timestamp" (which it is not in Unix).
+
+VOS perl can emulate Unix filenames with C</> as path separator. The
+native pathname characters greater-than, less-than, number-sign, and
+percent-sign are always accepted.
+
+S<RISC OS> perl can emulate Unix filenames with C</> as path
+separator, or go native and use C<.> for path separator and C<:> to
+signal filesystems and disk names.
+
+Don't assume Unix filesystem access semantics: that read, write,
+and execute are all the permissions there are, and even if they exist,
+that their semantics (for example what do r, w, and x mean on
+a directory) are the Unix ones. The various Unix/POSIX compatibility
+layers usually try to make interfaces like chmod() work, but sometimes
+there simply is no good mapping.
+
+If all this is intimidating, have no (well, maybe only a little)
+fear. There are modules that can help. The File::Spec modules
+provide methods to do the Right Thing on whatever platform happens
+to be running the program.
+
+ use File::Spec::Functions;
+ chdir(updir()); # go up one directory
+ my $file = catfile(curdir(), 'temp', 'file.txt');
+ # on Unix and Win32, './temp/file.txt'
+ # on Mac OS Classic, ':temp:file.txt'
+ # on VMS, '[.temp]file.txt'
+
+File::Spec is available in the standard distribution as of version
+5.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
+and some versions of perl come with version 0.6. If File::Spec
+is not updated to 0.7 or later, you must use the object-oriented
+interface from File::Spec (or upgrade File::Spec).
+
+In general, production code should not have file paths hardcoded.
+Making them user-supplied or read from a configuration file is
+better, keeping in mind that file path syntax varies on different
+machines.
+
+This is especially noticeable in scripts like Makefiles and test suites,
+which often assume C</> as a path separator for subdirectories.
+
+Also of use is File::Basename from the standard distribution, which
+splits a pathname into pieces (base filename, full path to directory,
+and file suffix).
+
+Even when on a single platform (if you can call Unix a single platform),
+remember not to count on the existence or the contents of particular
+system-specific files or directories, like F</etc/passwd>,
+F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
+example, F</etc/passwd> may exist but not contain the encrypted
+passwords, because the system is using some form of enhanced security.
+Or it may not contain all the accounts, because the system is using NIS.
+If code does need to rely on such a file, include a description of the
+file and its format in the code's documentation, then make it easy for
+the user to override the default location of the file.
+
+Don't assume a text file will end with a newline. They should,
+but people forget.
+
+Do not have two files or directories of the same name with different
+case, like F<test.pl> and F<Test.pl>, as many platforms have
+case-insensitive (or at least case-forgiving) filenames. Also, try
+not to have non-word characters (except for C<.>) in the names, and
+keep them to the 8.3 convention, for maximum portability, onerous a
+burden though this may appear.
+
+Likewise, when using the AutoSplit module, try to keep your functions to
+8.3 naming and case-insensitive conventions; or, at the least,
+make it so the resulting files have a unique (case-insensitively)
+first 8 characters.
+
+Whitespace in filenames is tolerated on most systems, but not all,
+and even on systems where it might be tolerated, some utilities
+might become confused by such whitespace.
+
+Many systems (DOS, VMS ODS-2) cannot have more than one C<.> in their
+filenames.
+
+Don't assume C<< > >> won't be the first character of a filename.
+Always use C<< < >> explicitly to open a file for reading, or even
+better, use the three-arg version of open, unless you want the user to
+be able to specify a pipe open.
+
+ open my $fh, '<', $existing_file) or die $!;
+
+If filenames might use strange characters, it is safest to open it
+with C<sysopen> instead of C<open>. C<open> is magic and can
+translate characters like C<< > >>, C<< < >>, and C<|>, which may
+be the wrong thing to do. (Sometimes, though, it's the right thing.)
+Three-arg open can also help protect against this translation in cases
+where it is undesirable.
+
+Don't use C<:> as a part of a filename since many systems use that for
+their own semantics (Mac OS Classic for separating pathname components,
+many networking schemes and utilities for separating the nodename and
+the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
+C<|>.
+
+Don't assume that in pathnames you can collapse two leading slashes
+C<//> into one: some networking and clustering filesystems have special
+semantics for that. Let the operating system to sort it out.
+
+The I<portable filename characters> as defined by ANSI C are
+
+ a b c d e f g h i j k l m n o p q r t u v w x y z
+ A B C D E F G H I J K L M N O P Q R T U V W X Y Z
+ 0 1 2 3 4 5 6 7 8 9
+ . _ -
+
+and the "-" shouldn't be the first character. If you want to be
+hypercorrect, stay case-insensitive and within the 8.3 naming
+convention (all the files and directories have to be unique within one
+directory if their names are lowercased and truncated to eight
+characters before the C<.>, if any, and to three characters after the
+C<.>, if any). (And do not use C<.>s in directory names.)
+
+=head2 System Interaction
+
+Not all platforms provide a command line. These are usually platforms
+that rely primarily on a Graphical User Interface (GUI) for user
+interaction. A program requiring a command line interface might
+not work everywhere. This is probably for the user of the program
+to deal with, so don't stay up late worrying about it.
+
+Some platforms can't delete or rename files held open by the system,
+this limitation may also apply to changing filesystem metainformation
+like file permissions or owners. Remember to C<close> files when you
+are done with them. Don't C<unlink> or C<rename> an open file. Don't
+C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
+it first.
+
+Don't open the same file more than once at a time for writing, as some
+operating systems put mandatory locks on such files.
+
+Don't assume that write/modify permission on a directory gives the
+right to add or delete files/directories in that directory. That is
+filesystem specific: in some filesystems you need write/modify
+permission also (or even just) in the file/directory itself. In some
+filesystems (AFS, DFS) the permission to add/delete directory entries
+is a completely separate permission.
+
+Don't assume that a single C<unlink> completely gets rid of the file:
+some filesystems (most notably the ones in VMS) have versioned
+filesystems, and unlink() removes only the most recent one (it doesn't
+remove all the versions because by default the native tools on those
+platforms remove just the most recent version, too). The portable
+idiom to remove all the versions of a file is
+
+ 1 while unlink "file";
+
+This will terminate if the file is undeleteable for some reason
+(protected, not there, and so on).
+
+Don't count on a specific environment variable existing in C<%ENV>.
+Don't count on C<%ENV> entries being case-sensitive, or even
+case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
+if you really have to, make it conditional on C<$^O ne 'VMS'> since in
+VMS the C<%ENV> table is much more than a per-process key-value string
+table.
+
+On VMS, some entries in the %ENV hash are dynamically created when
+their key is used on a read if they did not previously exist. The
+values for C<$ENV{HOME}>, C<$ENV{TERM}>, C<$ENV{HOME}>, and C<$ENV{USER}>,
+are known to be dynamically generated. The specific names that are
+dynamically generated may vary with the version of the C library on VMS,
+and more may exist than is documented.
+
+On VMS by default, changes to the %ENV hash are persistent after the process
+exits. This can cause unintended issues.
+
+Don't count on signals or C<%SIG> for anything.
+
+Don't count on filename globbing. Use C<opendir>, C<readdir>, and
+C<closedir> instead.
+
+Don't count on per-program environment variables, or per-program current
+directories.
+
+Don't count on specific values of C<$!>, neither numeric nor
+especially the strings values. Users may switch their locales causing
+error messages to be translated into their languages. If you can
+trust a POSIXish environment, you can portably use the symbols defined
+by the Errno module, like ENOENT. And don't trust on the values of C<$!>
+at all except immediately after a failed system call.
+
+=head2 Command names versus file pathnames
+
+Don't assume that the name used to invoke a command or program with
+C<system> or C<exec> can also be used to test for the existence of the
+file that holds the executable code for that command or program.
+First, many systems have "internal" commands that are built-in to the
+shell or OS and while these commands can be invoked, there is no
+corresponding file. Second, some operating systems (e.g., Cygwin,
+DJGPP, OS/2, and VOS) have required suffixes for executable files;
+these suffixes are generally permitted on the command name but are not
+required. Thus, a command like "perl" might exist in a file named
+"perl", "perl.exe", or "perl.pm", depending on the operating system.
+The variable "_exe" in the Config module holds the executable suffix,
+if any. Third, the VMS port carefully sets up $^X and
+$Config{perlpath} so that no further processing is required. This is
+just as well, because the matching regular expression used below would
+then have to deal with a possible trailing version number in the VMS
+file name.
+
+To convert $^X to a file pathname, taking account of the requirements
+of the various operating system possibilities, say:
+
+ use Config;
+ my $thisperl = $^X;
+ if ($^O ne 'VMS')
+ {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
+
+To convert $Config{perlpath} to a file pathname, say:
+
+ use Config;
+ my $thisperl = $Config{perlpath};
+ if ($^O ne 'VMS')
+ {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
+
+=head2 Networking
+
+Don't assume that you can reach the public Internet.
+
+Don't assume that there is only one way to get through firewalls
+to the public Internet.
+
+Don't assume that you can reach outside world through any other port
+than 80, or some web proxy. ftp is blocked by many firewalls.
+
+Don't assume that you can send email by connecting to the local SMTP port.
+
+Don't assume that you can reach yourself or any node by the name
+'localhost'. The same goes for '127.0.0.1'. You will have to try both.
+
+Don't assume that the host has only one network card, or that it
+can't bind to many virtual IP addresses.
+
+Don't assume a particular network device name.
+
+Don't assume a particular set of ioctl()s will work.
+
+Don't assume that you can ping hosts and get replies.
+
+Don't assume that any particular port (service) will respond.
+
+Don't assume that Sys::Hostname (or any other API or command) returns
+either a fully qualified hostname or a non-qualified hostname: it all
+depends on how the system had been configured. Also remember that for
+things such as DHCP and NAT, the hostname you get back might not be
+very useful.
+
+All the above "don't":s may look daunting, and they are, but the key
+is to degrade gracefully if one cannot reach the particular network
+service one wants. Croaking or hanging do not look very professional.
+
+=head2 Interprocess Communication (IPC)
+
+In general, don't directly access the system in code meant to be
+portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
+C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
+that makes being a perl hacker worth being.
+
+Commands that launch external processes are generally supported on
+most platforms (though many of them do not support any type of
+forking). The problem with using them arises from what you invoke
+them on. External tools are often named differently on different
+platforms, may not be available in the same location, might accept
+different arguments, can behave differently, and often present their
+results in a platform-dependent way. Thus, you should seldom depend
+on them to produce consistent results. (Then again, if you're calling
+I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
+
+One especially common bit of Perl code is opening a pipe to B<sendmail>:
+
+ open(MAIL, '|/usr/lib/sendmail -t')
+ or die "cannot fork sendmail: $!";
+
+This is fine for systems programming when sendmail is known to be
+available. But it is not fine for many non-Unix systems, and even
+some Unix systems that may not have sendmail installed. If a portable
+solution is needed, see the various distributions on CPAN that deal
+with it. Mail::Mailer and Mail::Send in the MailTools distribution are
+commonly used, and provide several mailing methods, including mail,
+sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
+not available. Mail::Sendmail is a standalone module that provides
+simple, platform-independent mailing.
+
+The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
+even on all Unix platforms.
+
+Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
+bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
+both forms just pack the four bytes into network order. That this
+would be equal to the C language C<in_addr> struct (which is what the
+socket code internally uses) is not guaranteed. To be portable use
+the routines of the Socket extension, such as C<inet_aton()>,
+C<inet_ntoa()>, and C<sockaddr_in()>.
+
+The rule of thumb for portable code is: Do it all in portable Perl, or
+use a module (that may internally implement it with platform-specific
+code, but expose a common interface).
+
+=head2 External Subroutines (XS)
+
+XS code can usually be made to work with any platform, but dependent
+libraries, header files, etc., might not be readily available or
+portable, or the XS code itself might be platform-specific, just as Perl
+code might be. If the libraries and headers are portable, then it is
+normally reasonable to make sure the XS code is portable, too.
+
+A different type of portability issue arises when writing XS code:
+availability of a C compiler on the end-user's system. C brings
+with it its own portability issues, and writing XS code will expose
+you to some of those. Writing purely in Perl is an easier way to
+achieve portability.
+
+=head2 Standard Modules
+
+In general, the standard modules work across platforms. Notable
+exceptions are the CPAN module (which currently makes connections to external
+programs that may not be available), platform-specific modules (like
+ExtUtils::MM_VMS), and DBM modules.
+
+There is no one DBM module available on all platforms.
+SDBM_File and the others are generally available on all Unix and DOSish
+ports, but not in MacPerl, where only NBDM_File and DB_File are
+available.
+
+The good news is that at least some DBM module should be available, and
+AnyDBM_File will use whichever module it can find. Of course, then
+the code needs to be fairly strict, dropping to the greatest common
+factor (e.g., not exceeding 1K for each record), so that it will
+work with any DBM module. See L<AnyDBM_File> for more details.
+
+=head2 Time and Date
+
+The system's notion of time of day and calendar date is controlled in
+widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
+and even if it is, don't assume that you can control the timezone through
+that variable. Don't assume anything about the three-letter timezone
+abbreviations (for example that MST would be the Mountain Standard Time,
+it's been known to stand for Moscow Standard Time). If you need to
+use timezones, express them in some unambiguous format like the
+exact number of minutes offset from UTC, or the POSIX timezone
+format.
+
+Don't assume that the epoch starts at 00:00:00, January 1, 1970,
+because that is OS- and implementation-specific. It is better to
+store a date in an unambiguous representation. The ISO 8601 standard
+defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
+(that's a literal "T" separating the date from the time).
+Please do use the ISO 8601 instead of making us to guess what
+date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
+A text representation (like "1987-12-18") can be easily converted
+into an OS-specific value using a module like Date::Parse.
+An array of values, such as those returned by C<localtime>, can be
+converted to an OS-specific representation using Time::Local.
+
+When calculating specific times, such as for tests in time or date modules,
+it may be appropriate to calculate an offset for the epoch.
+
+ require Time::Local;
+ my $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
+
+The value for C<$offset> in Unix will be C<0>, but in Mac OS Classic
+will be some large number. C<$offset> can then be added to a Unix time
+value to get what should be the proper value on any system.
+
+=head2 Character sets and character encoding
+
+Assume very little about character sets.
+
+Assume nothing about numerical values (C<ord>, C<chr>) of characters.
+Do not use explicit code point ranges (like \xHH-\xHH); use for
+example symbolic character classes like C<[:print:]>.
+
+Do not assume that the alphabetic characters are encoded contiguously
+(in the numeric sense). There may be gaps.
+
+Do not assume anything about the ordering of the characters.
+The lowercase letters may come before or after the uppercase letters;
+the lowercase and uppercase may be interlaced so that both "a" and "A"
+come before "b"; the accented and other international characters may
+be interlaced so that E<auml> comes before "b".
+
+=head2 Internationalisation
+
+If you may assume POSIX (a rather large assumption), you may read
+more about the POSIX locale system from L<perllocale>. The locale
+system at least attempts to make things a little bit more portable,
+or at least more convenient and native-friendly for non-English
+users. The system affects character sets and encoding, and date
+and time formatting--amongst other things.
+
+If you really want to be international, you should consider Unicode.
+See L<perluniintro> and L<perlunicode> for more information.
+
+If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
+the "source code" of your code, to be portable you have to be explicit
+about what bytes they are. Someone might for example be using your
+code under a UTF-8 locale, in which case random native bytes might be
+illegal ("Malformed UTF-8 ...") This means that for example embedding
+ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
+later. If the bytes are native 8-bit bytes, you can use the C<bytes>
+pragma. If the bytes are in a string (regular expression being a
+curious string), you can often also use the C<\xHH> notation instead
+of embedding the bytes as-is. (If you want to write your code in UTF-8,
+you can use the C<utf8>.) The C<bytes> and C<utf8> pragmata are
+available since Perl 5.6.0.
+
+=head2 System Resources
+
+If your code is destined for systems with severely constrained (or
+missing!) virtual memory systems then you want to be I<especially> mindful
+of avoiding wasteful constructs such as:
+
+ # NOTE: this is no longer "bad" in perl5.005
+ for (0..10000000) {} # bad
+ for (my $x = 0; $x <= 10000000; ++$x) {} # good
+
+ my @lines = <$very_large_file>; # bad
+
+ while (<$fh>) {$file .= $_} # sometimes bad
+ my $file = join('', <$fh>); # better
+
+The last two constructs may appear unintuitive to most people. The
+first repeatedly grows a string, whereas the second allocates a
+large chunk of memory in one go. On some systems, the second is
+more efficient that the first.
+
+=head2 Security
+
+Most multi-user platforms provide basic levels of security, usually
+implemented at the filesystem level. Some, however, unfortunately do
+not. Thus the notion of user id, or "home" directory,
+or even the state of being logged-in, may be unrecognizable on many
+platforms. If you write programs that are security-conscious, it
+is usually best to know what type of system you will be running
+under so that you can write code explicitly for that platform (or
+class of platforms).
+
+Don't assume the Unix filesystem access semantics: the operating
+system or the filesystem may be using some ACL systems, which are
+richer languages than the usual rwx. Even if the rwx exist,
+their semantics might be different.
+
+(From security viewpoint testing for permissions before attempting to
+do something is silly anyway: if one tries this, there is potential
+for race conditions. Someone or something might change the
+permissions between the permissions check and the actual operation.
+Just try the operation.)
+
+Don't assume the Unix user and group semantics: especially, don't
+expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
+for switching identities (or memberships).
+
+Don't assume set-uid and set-gid semantics. (And even if you do,
+think twice: set-uid and set-gid are a known can of security worms.)
+
+=head2 Style
+
+For those times when it is necessary to have platform-specific code,
+consider keeping the platform-specific code in one place, making porting
+to other platforms easier. Use the Config module and the special
+variable C<$^O> to differentiate platforms, as described in
+L<"PLATFORMS">.
+
+Be careful in the tests you supply with your module or programs.
+Module code may be fully portable, but its tests might not be. This
+often happens when tests spawn off other processes or call external
+programs to aid in the testing, or when (as noted above) the tests
+assume certain things about the filesystem and paths. Be careful not
+to depend on a specific output style for errors, such as when checking
+C<$!> after a failed system call. Using C<$!> for anything else than
+displaying it as output is doubtful (though see the Errno module for
+testing reasonably portably for error value). Some platforms expect
+a certain output format, and Perl on those platforms may have been
+adjusted accordingly. Most specifically, don't anchor a regex when
+testing an error value.
+
+=head1 CPAN Testers
+
+Modules uploaded to CPAN are tested by a variety of volunteers on
+different platforms. These CPAN testers are notified by mail of each
+new upload, and reply to the list with PASS, FAIL, NA (not applicable to
+this platform), or UNKNOWN (unknown), along with any relevant notations.
+
+The purpose of the testing is twofold: one, to help developers fix any
+problems in their code that crop up because of lack of testing on other
+platforms; two, to provide users with information about whether
+a given module works on a given platform.
+
+Also see:
+
+=over 4
+
+=item *
+
+Mailing list: cpan-testers@perl.org
+
+=item *
+
+Testing results: http://testers.cpan.org/
+
+=back
+
+=head1 PLATFORMS
+
+As of version 5.002, Perl is built with a C<$^O> variable that
+indicates the operating system it was built on. This was implemented
+to help speed up code that would otherwise have to C<use Config>
+and use the value of C<$Config{osname}>. Of course, to get more
+detailed information about the system, looking into C<%Config> is
+certainly recommended.
+
+C<%Config> cannot always be trusted, however, because it was built
+at compile time. If perl was built in one place, then transferred
+elsewhere, some values may be wrong. The values may even have been
+edited after the fact.
+
+=head2 Unix
+
+Perl works on a bewildering variety of Unix and Unix-like platforms (see
+e.g. most of the files in the F<hints/> directory in the source code kit).
+On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
+too) is determined either by lowercasing and stripping punctuation from the
+first field of the string returned by typing C<uname -a> (or a similar command)
+at the shell prompt or by testing the file system for the presence of
+uniquely named files such as a kernel or header file. Here, for example,
+are a few of the more popular Unix flavors:
+
+ uname $^O $Config{'archname'}
+ --------------------------------------------
+ AIX aix aix
+ BSD/OS bsdos i386-bsdos
+ Darwin darwin darwin
+ dgux dgux AViiON-dgux
+ DYNIX/ptx dynixptx i386-dynixptx
+ FreeBSD freebsd freebsd-i386
+ Haiku haiku BePC-haiku
+ Linux linux arm-linux
+ Linux linux i386-linux
+ Linux linux i586-linux
+ Linux linux ppc-linux
+ HP-UX hpux PA-RISC1.1
+ IRIX irix irix
+ Mac OS X darwin darwin
+ NeXT 3 next next-fat
+ NeXT 4 next OPENSTEP-Mach
+ openbsd openbsd i386-openbsd
+ OSF1 dec_osf alpha-dec_osf
+ reliantunix-n svr4 RM400-svr4
+ SCO_SV sco_sv i386-sco_sv
+ SINIX-N svr4 RM400-svr4
+ sn4609 unicos CRAY_C90-unicos
+ sn6521 unicosmk t3e-unicosmk
+ sn9617 unicos CRAY_J90-unicos
+ SunOS solaris sun4-solaris
+ SunOS solaris i86pc-solaris
+ SunOS4 sunos sun4-sunos
+
+Because the value of C<$Config{archname}> may depend on the
+hardware architecture, it can vary more than the value of C<$^O>.
+
+=head2 DOS and Derivatives
+
+Perl has long been ported to Intel-style microcomputers running under
+systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
+bring yourself to mention (except for Windows CE, if you count that).
+Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
+be aware that each of these file specifications may have subtle
+differences:
+
+ my $filespec0 = "c:/foo/bar/file.txt";
+ my $filespec1 = "c:\\foo\\bar\\file.txt";
+ my $filespec2 = 'c:\foo\bar\file.txt';
+ my $filespec3 = 'c:\\foo\\bar\\file.txt';
+
+System calls accept either C</> or C<\> as the path separator.
+However, many command-line utilities of DOS vintage treat C</> as
+the option prefix, so may get confused by filenames containing C</>.
+Aside from calling any external programs, C</> will work just fine,
+and probably better, as it is more consistent with popular usage,
+and avoids the problem of remembering what to backwhack and what
+not to.
+
+The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
+the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
+filesystems you may have to be careful about case returned with functions
+like C<readdir> or used with functions like C<open> or C<opendir>.
+
+DOS also treats several filenames as special, such as AUX, PRN,
+NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
+filenames won't even work if you include an explicit directory
+prefix. It is best to avoid such filenames, if you want your code
+to be portable to DOS and its derivatives. It's hard to know what
+these all are, unfortunately.
+
+Users of these operating systems may also wish to make use of
+scripts such as I<pl2bat.bat> or I<pl2cmd> to
+put wrappers around your scripts.
+
+Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
+and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
+will keep C<\n> translated as C<\012> for that filehandle. Since it is a
+no-op on other systems, C<binmode> should be used for cross-platform code
+that deals with binary data. That's assuming you realize in advance
+that your data is in binary. General-purpose programs should
+often assume nothing about their data.
+
+The C<$^O> variable and the C<$Config{archname}> values for various
+DOSish perls are as follows:
+
+ OS $^O $Config{archname} ID Version
+ --------------------------------------------------------
+ MS-DOS dos ?
+ PC-DOS dos ?
+ OS/2 os2 ?
+ Windows 3.1 ? ? 0 3 01
+ Windows 95 MSWin32 MSWin32-x86 1 4 00
+ Windows 98 MSWin32 MSWin32-x86 1 4 10
+ Windows ME MSWin32 MSWin32-x86 1 ?
+ Windows NT MSWin32 MSWin32-x86 2 4 xx
+ Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
+ Windows NT MSWin32 MSWin32-ppc 2 4 xx
+ Windows 2000 MSWin32 MSWin32-x86 2 5 00
+ Windows XP MSWin32 MSWin32-x86 2 5 01
+ Windows 2003 MSWin32 MSWin32-x86 2 5 02
+ Windows Vista MSWin32 MSWin32-x86 2 6 00
+ Windows 7 MSWin32 MSWin32-x86 2 6 01
+ Windows 7 MSWin32 MSWin32-x64 2 6 01
+ Windows CE MSWin32 ? 3
+ Cygwin cygwin cygwin
+
+The various MSWin32 Perl's can distinguish the OS they are running on
+via the value of the fifth element of the list returned from
+Win32::GetOSVersion(). For example:
+
+ if ($^O eq 'MSWin32') {
+ my @os_version_info = Win32::GetOSVersion();
+ print +('3.1','95','NT')[$os_version_info[4]],"\n";
+ }
+
+There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
+and as of libwin32 0.19 (not part of the core Perl distribution)
+Win32::GetOSName(). The very portable POSIX::uname() will work too:
+
+ c:\> perl -MPOSIX -we "print join '|', uname"
+ Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
+
+Also see:
+
+=over 4
+
+=item *
+
+The djgpp environment for DOS, http://www.delorie.com/djgpp/
+and L<perldos>.
+
+=item *
+
+The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
+ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
+
+=item *
+
+Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
+in L<perlcygwin>.
+
+=item *
+
+The C<Win32::*> modules in L<Win32>.
+
+=item *
+
+The ActiveState Pages, http://www.activestate.com/
+
+=item *
+
+The Cygwin environment for Win32; F<README.cygwin> (installed
+as L<perlcygwin>), http://www.cygwin.com/
+
+=item *
+
+The U/WIN environment for Win32,
+http://www.research.att.com/sw/tools/uwin/
+
+=item *
+
+Build instructions for OS/2, L<perlos2>
+
+=back
+
+=head2 VMS
+
+Perl on VMS is discussed in L<perlvms> in the perl distribution.
+
+The official name of VMS as of this writing is OpenVMS.
+
+Perl on VMS can accept either VMS- or Unix-style file
+specifications as in either of the following:
+
+ $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
+ $ perl -ne "print if /perl_setup/i" /sys$login/login.com
+
+but not a mixture of both as in:
+
+ $ perl -ne "print if /perl_setup/i" sys$login:/login.com
+ Can't open sys$login:/login.com: file specification syntax error
+
+Interacting with Perl from the Digital Command Language (DCL) shell
+often requires a different set of quotation marks than Unix shells do.
+For example:
+
+ $ perl -e "print ""Hello, world.\n"""
+ Hello, world.
+
+There are several ways to wrap your perl scripts in DCL F<.COM> files, if
+you are so inclined. For example:
+
+ $ write sys$output "Hello from DCL!"
+ $ if p1 .eqs. ""
+ $ then perl -x 'f$environment("PROCEDURE")
+ $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
+ $ deck/dollars="__END__"
+ #!/usr/bin/perl
+
+ print "Hello from Perl!\n";
+
+ __END__
+ $ endif
+
+Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
+perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
+
+The VMS operating system has two filesystems, known as ODS-2 and ODS-5.
+
+For ODS-2, filenames are in the format "name.extension;version". The
+maximum length for filenames is 39 characters, and the maximum length for
+extensions is also 39 characters. Version is a number from 1 to
+32767. Valid characters are C</[A-Z0-9$_-]/>.
+
+The ODS-2 filesystem is case-insensitive and does not preserve case.
+Perl simulates this by converting all filenames to lowercase internally.
+
+For ODS-5, filenames may have almost any character in them and can include
+Unicode characters. Characters that could be misinterpreted by the DCL
+shell or file parsing utilities need to be prefixed with the C<^>
+character, or replaced with hexadecimal characters prefixed with the
+C<^> character. Such prefixing is only needed with the pathnames are
+in VMS format in applications. Programs that can accept the Unix format
+of pathnames do not need the escape characters. The maximum length for
+filenames is 255 characters. The ODS-5 file system can handle both
+a case preserved and a case sensitive mode.
+
+ODS-5 is only available on the OpenVMS for 64 bit platforms.
+
+Support for the extended file specifications is being done as optional
+settings to preserve backward compatibility with Perl scripts that
+assume the previous VMS limitations.
+
+In general routines on VMS that get a Unix format file specification
+should return it in a Unix format, and when they get a VMS format
+specification they should return a VMS format unless they are documented
+to do a conversion.
+
+For routines that generate return a file specification, VMS allows setting
+if the C library which Perl is built on if it will be returned in VMS
+format or in Unix format.
+
+With the ODS-2 file system, there is not much difference in syntax of
+filenames without paths for VMS or Unix. With the extended character
+set available with ODS-5 there can be a significant difference.
+
+Because of this, existing Perl scripts written for VMS were sometimes
+treating VMS and Unix filenames interchangeably. Without the extended
+character set enabled, this behavior will mostly be maintained for
+backwards compatibility.
+
+When extended characters are enabled with ODS-5, the handling of
+Unix formatted file specifications is to that of a Unix system.
+
+VMS file specifications without extensions have a trailing dot. An
+equivalent Unix file specification should not show the trailing dot.
+
+The result of all of this, is that for VMS, for portable scripts, you
+can not depend on Perl to present the filenames in lowercase, to be
+case sensitive, and that the filenames could be returned in either
+Unix or VMS format.
+
+And if a routine returns a file specification, unless it is intended to
+convert it, it should return it in the same format as it found it.
+
+C<readdir> by default has traditionally returned lowercased filenames.
+When the ODS-5 support is enabled, it will return the exact case of the
+filename on the disk.
+
+Files without extensions have a trailing period on them, so doing a
+C<readdir> in the default mode with a file named F<A.;5> will
+return F<a.> when VMS is (though that file could be opened with
+C<open(FH, 'A')>).
+
+With support for extended file specifications and if C<opendir> was
+given a Unix format directory, a file named F<A.;5> will return F<a>
+and optionally in the exact case on the disk. When C<opendir> is given
+a VMS format directory, then C<readdir> should return F<a.>, and
+again with the optionally the exact case.
+
+RMS had an eight level limit on directory depths from any rooted logical
+(allowing 16 levels overall) prior to VMS 7.2, and even with versions of
+VMS on VAX up through 7.3. Hence C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a
+valid directory specification but C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is
+not. F<Makefile.PL> authors might have to take this into account, but at
+least they can refer to the former as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
+
+Pumpkings and module integrators can easily see whether files with too many
+directory levels have snuck into the core by running the following in the
+top-level source directory:
+
+ $ perl -ne "$_=~s/\s+.*//; print if scalar(split /\//) > 8;" < MANIFEST
+
+
+The VMS::Filespec module, which gets installed as part of the build
+process on VMS, is a pure Perl module that can easily be installed on
+non-VMS platforms and can be helpful for conversions to and from RMS
+native formats. It is also now the only way that you should check to
+see if VMS is in a case sensitive mode.
+
+What C<\n> represents depends on the type of file opened. It usually
+represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
+C<\000>, C<\040>, or nothing depending on the file organization and
+record format. The VMS::Stdio module provides access to the
+special fopen() requirements of files with unusual attributes on VMS.
+
+TCP/IP stacks are optional on VMS, so socket routines might not be
+implemented. UDP sockets may not be supported.
+
+The TCP/IP library support for all current versions of VMS is dynamically
+loaded if present, so even if the routines are configured, they may
+return a status indicating that they are not implemented.
+
+The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
+that you are running on without resorting to loading all of C<%Config>
+you can examine the content of the C<@INC> array like so:
+
+ if (grep(/VMS_AXP/, @INC)) {
+ print "I'm on Alpha!\n";
+
+ } elsif (grep(/VMS_VAX/, @INC)) {
+ print "I'm on VAX!\n";
+
+ } elsif (grep(/VMS_IA64/, @INC)) {
+ print "I'm on IA64!\n";
+
+ } else {
+ print "I'm not so sure about where $^O is...\n";
+ }
+
+In general, the significant differences should only be if Perl is running
+on VMS_VAX or one of the 64 bit OpenVMS platforms.
+
+On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
+logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
+calls to C<localtime> are adjusted to count offsets from
+01-JAN-1970 00:00:00.00, just like Unix.
+
+Also see:
+
+=over 4
+
+=item *
+
+F<README.vms> (installed as L<README_vms>), L<perlvms>
+
+=item *
+
+vmsperl list, vmsperl-subscribe@perl.org
+
+=item *
+
+vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
+
+=back
+
+=head2 VOS
+
+Perl on VOS (also known as OpenVOS) is discussed in F<README.vos>
+in the perl distribution (installed as L<perlvos>). Perl on VOS
+can accept either VOS- or Unix-style file specifications as in
+either of the following:
+
+ $ perl -ne "print if /perl_setup/i" >system>notices
+ $ perl -ne "print if /perl_setup/i" /system/notices
+
+or even a mixture of both as in:
+
+ $ perl -ne "print if /perl_setup/i" >system/notices
+
+Even though VOS allows the slash character to appear in object
+names, because the VOS port of Perl interprets it as a pathname
+delimiting character, VOS files, directories, or links whose
+names contain a slash character cannot be processed. Such files
+must be renamed before they can be processed by Perl.
+
+Older releases of VOS (prior to OpenVOS Release 17.0) limit file
+names to 32 or fewer characters, prohibit file names from
+starting with a C<-> character, and prohibit file names from
+containing any character matching C<< tr/ !#%&'()*;<=>?// >>.
+
+Newer releases of VOS (OpenVOS Release 17.0 or later) support a
+feature known as extended names. On these releases, file names
+can contain up to 255 characters, are prohibited from starting
+with a C<-> character, and the set of prohibited characters is
+reduced to any character matching C<< tr/#%*<>?// >>. There are
+restrictions involving spaces and apostrophies: these characters
+must not begin or end a name, nor can they immediately precede or
+follow a period. Additionally, a space must not immediately
+precede another space or hyphen. Specifically, the following
+character combinations are prohibited: space-space,
+space-hyphen, period-space, space-period, period-apostrophe,
+apostrophe-period, leading or trailing space, and leading or
+trailing apostrophe. Although an extended file name is limited
+to 255 characters, a path name is still limited to 256
+characters.
+
+The value of C<$^O> on VOS is "VOS". To determine the
+architecture that you are running on without resorting to loading
+all of C<%Config> you can examine the content of the @INC array
+like so:
+
+ if ($^O =~ /VOS/) {
+ print "I'm on a Stratus box!\n";
+ } else {
+ print "I'm not on a Stratus box!\n";
+ die;
+ }
+
+Also see:
+
+=over 4
+
+=item *
+
+F<README.vos> (installed as L<perlvos>)
+
+=item *
+
+The VOS mailing list.
+
+There is no specific mailing list for Perl on VOS. You can post
+comments to the comp.sys.stratus newsgroup, or use the contact
+information located in the distribution files on the Stratus
+Anonymous FTP site.
+
+=item *
+
+VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
+
+=back
+
+=head2 EBCDIC Platforms
+
+Recent versions of Perl have been ported to platforms such as OS/400 on
+AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
+Mainframes. Such computers use EBCDIC character sets internally (usually
+Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
+systems). On the mainframe perl currently works under the "Unix system
+services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
+the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
+See L<perlos390> for details. Note that for OS/400 there is also a port of
+Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
+ILE which is EBCDIC-based), see L<perlos400>.
+
+As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
+sub-systems do not support the C<#!> shebang trick for script invocation.
+Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
+similar to the following simple script:
+
+ : # use perl
+ eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
+ if 0;
+ #!/usr/local/bin/perl # just a comment really
+
+ print "Hello from perl!\n";
+
+OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
+Calls to C<system> and backticks can use POSIX shell syntax on all
+S/390 systems.
+
+On the AS/400, if PERL5 is in your library list, you may need
+to wrap your perl scripts in a CL procedure to invoke them like so:
+
+ BEGIN
+ CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
+ ENDPGM
+
+This will invoke the perl script F<hello.pl> in the root of the
+QOpenSys file system. On the AS/400 calls to C<system> or backticks
+must use CL syntax.
+
+On these platforms, bear in mind that the EBCDIC character set may have
+an effect on what happens with some perl functions (such as C<chr>,
+C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
+well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
+and C<|>, not to mention dealing with socket interfaces to ASCII computers
+(see L<"Newlines">).
+
+Fortunately, most web servers for the mainframe will correctly
+translate the C<\n> in the following statement to its ASCII equivalent
+(C<\r> is the same under both Unix and OS/390 & VM/ESA):
+
+ print "Content-type: text/html\r\n\r\n";
+
+The values of C<$^O> on some of these platforms includes:
+
+ uname $^O $Config{'archname'}
+ --------------------------------------------
+ OS/390 os390 os390
+ OS400 os400 os400
+ POSIX-BC posix-bc BS2000-posix-bc
+ VM/ESA vmesa vmesa
+
+Some simple tricks for determining if you are running on an EBCDIC
+platform could include any of the following (perhaps all):
+
+ if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
+
+ if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
+
+ if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
+
+One thing you may not want to rely on is the EBCDIC encoding
+of punctuation characters since these may differ from code page to code
+page (and once your module or script is rumoured to work with EBCDIC,
+folks will want it to work with all EBCDIC character sets).
+
+Also see:
+
+=over 4
+
+=item *
+
+L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
+L<perlebcdic>.
+
+=item *
+
+The perl-mvs@perl.org list is for discussion of porting issues as well as
+general usage issues for all EBCDIC Perls. Send a message body of
+"subscribe perl-mvs" to majordomo@perl.org.
+
+=item *
+
+AS/400 Perl information at
+http://as400.rochester.ibm.com/
+as well as on CPAN in the F<ports/> directory.
+
+=back
+
+=head2 Acorn RISC OS
+
+Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
+Unix, and because Unix filename emulation is turned on by default,
+most simple scripts will probably work "out of the box". The native
+filesystem is modular, and individual filesystems are free to be
+case-sensitive or insensitive, and are usually case-preserving. Some
+native filesystems have name length limits, which file and directory
+names are silently truncated to fit. Scripts should be aware that the
+standard filesystem currently has a name length limit of B<10>
+characters, with up to 77 items in a directory, but other filesystems
+may not impose such limitations.
+
+Native filenames are of the form
+
+ Filesystem#Special_Field::DiskName.$.Directory.Directory.File
+
+where
+
+ Special_Field is not usually present, but may contain . and $ .
+ Filesystem =~ m|[A-Za-z0-9_]|
+ DsicName =~ m|[A-Za-z0-9_/]|
+ $ represents the root directory
+ . is the path separator
+ @ is the current directory (per filesystem but machine global)
+ ^ is the parent directory
+ Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
+
+The default filename translation is roughly C<tr|/.|./|;>
+
+Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
+the second stage of C<$> interpolation in regular expressions will fall
+foul of the C<$.> if scripts are not careful.
+
+Logical paths specified by system variables containing comma-separated
+search lists are also allowed; hence C<System:Modules> is a valid
+filename, and the filesystem will prefix C<Modules> with each section of
+C<System$Path> until a name is made that points to an object on disk.
+Writing to a new file C<System:Modules> would be allowed only if
+C<System$Path> contains a single item list. The filesystem will also
+expand system variables in filenames if enclosed in angle brackets, so
+C<< <System$Dir>.Modules >> would look for the file
+S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
+that B<fully qualified filenames can start with C<< <> >>> and should
+be protected when C<open> is used for input.
+
+Because C<.> was in use as a directory separator and filenames could not
+be assumed to be unique after 10 characters, Acorn implemented the C
+compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
+filenames specified in source code and store the respective files in
+subdirectories named after the suffix. Hence files are translated:
+
+ foo.h h.foo
+ C:foo.h C:h.foo (logical path variable)
+ sys/os.h sys.h.os (C compiler groks Unix-speak)
+ 10charname.c c.10charname
+ 10charname.o o.10charname
+ 11charname_.c c.11charname (assuming filesystem truncates at 10)
+
+The Unix emulation library's translation of filenames to native assumes
+that this sort of translation is required, and it allows a user-defined list
+of known suffixes that it will transpose in this fashion. This may
+seem transparent, but consider that with these rules C<foo/bar/baz.h>
+and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
+C<glob> cannot and do not attempt to emulate the reverse mapping. Other
+C<.>'s in filenames are translated to C</>.
+
+As implied above, the environment accessed through C<%ENV> is global, and
+the convention is that program specific environment variables are of the
+form C<Program$Name>. Each filesystem maintains a current directory,
+and the current filesystem's current directory is the B<global> current
+directory. Consequently, sociable programs don't change the current
+directory but rely on full pathnames, and programs (and Makefiles) cannot
+assume that they can spawn a child process which can change the current
+directory without affecting its parent (and everyone else for that
+matter).
+
+Because native operating system filehandles are global and are currently
+allocated down from 255, with 0 being a reserved value, the Unix emulation
+library emulates Unix filehandles. Consequently, you can't rely on
+passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
+
+The desire of users to express filenames of the form
+C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
+too: C<``> command output capture has to perform a guessing game. It
+assumes that a string C<< <[^<>]+\$[^<>]> >> is a
+reference to an environment variable, whereas anything else involving
+C<< < >> or C<< > >> is redirection, and generally manages to be 99%
+right. Of course, the problem remains that scripts cannot rely on any
+Unix tools being available, or that any tools found have Unix-like command
+line arguments.
+
+Extensions and XS are, in theory, buildable by anyone using free
+tools. In practice, many don't, as users of the Acorn platform are
+used to binary distributions. MakeMaker does run, but no available
+make currently copes with MakeMaker's makefiles; even if and when
+this should be fixed, the lack of a Unix-like shell will cause
+problems with makefile rules, especially lines of the form C<cd
+sdbm && make all>, and anything using quoting.
+
+"S<RISC OS>" is the proper name for the operating system, but the value
+in C<$^O> is "riscos" (because we don't like shouting).
+
+=head2 Other perls
+
+Perl has been ported to many platforms that do not fit into any of
+the categories listed above. Some, such as AmigaOS, BeOS, HP MPE/iX,
+QNX, Plan 9, and VOS, have been well-integrated into the standard
+Perl source code kit. You may need to see the F<ports/> directory
+on CPAN for information, and possibly binaries, for the likes of:
+aos, Atari ST, lynxos, riscos, Novell Netware, Tandem Guardian,
+I<etc.> (Yes, we know that some of these OSes may fall under the
+Unix category, but we are not a standards body.)
+
+Some approximate operating system names and their C<$^O> values
+in the "OTHER" category include:
+
+ OS $^O $Config{'archname'}
+ ------------------------------------------
+ Amiga DOS amigaos m68k-amigos
+ BeOS beos
+ MPE/iX mpeix PA-RISC1.1
+
+See also:
+
+=over 4
+
+=item *
+
+Amiga, F<README.amiga> (installed as L<perlamiga>).
+
+=item *
+
+Be OS, F<README.beos>
+
+=item *
+
+HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
+http://www.bixby.org/mark/porting.html
+
+=item *
+
+A free perl5-based PERL.NLM for Novell Netware is available in
+precompiled binary and source code form from http://www.novell.com/
+as well as from CPAN.
+
+=item *
+
+S<Plan 9>, F<README.plan9>
+
+=back
+
+=head1 FUNCTION IMPLEMENTATIONS
+
+Listed below are functions that are either completely unimplemented
+or else have been implemented differently on various platforms.
+Following each description will be, in parentheses, a list of
+platforms that the description applies to.
+
+The list may well be incomplete, or even wrong in some places. When
+in doubt, consult the platform-specific README files in the Perl
+source distribution, and any other documentation resources accompanying
+a given port.
+
+Be aware, moreover, that even among Unix-ish systems there are variations.
+
+For many functions, you can also query C<%Config>, exported by
+default from the Config module. For example, to check whether the
+platform has the C<lstat> call, check C<$Config{d_lstat}>. See
+L<Config> for a full description of available variables.
+
+=head2 Alphabetical Listing of Perl Functions
+
+=over 8
+
+=item -X
+
+C<-w> only inspects the read-only file attribute (FILE_ATTRIBUTE_READONLY),
+which determines whether the directory can be deleted, not whether it can
+be written to. Directories always have read and write access unless denied
+by discretionary access control lists (DACLs). (S<Win32>)
+
+C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
+which may not reflect UIC-based file protections. (VMS)
+
+C<-s> by name on an open file will return the space reserved on disk,
+rather than the current extent. C<-s> on an open filehandle returns the
+current size. (S<RISC OS>)
+
+C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
+C<-x>, C<-o>. (Win32, VMS, S<RISC OS>)
+
+C<-g>, C<-k>, C<-l>, C<-u>, C<-A> are not particularly meaningful.
+(Win32, VMS, S<RISC OS>)
+
+C<-p> is not particularly meaningful. (VMS, S<RISC OS>)
+
+C<-d> is true if passed a device spec without an explicit directory.
+(VMS)
+
+C<-x> (or C<-X>) determine if a file ends in one of the executable
+suffixes. C<-S> is meaningless. (Win32)
+
+C<-x> (or C<-X>) determine if a file has an executable file type.
+(S<RISC OS>)
+
+=item alarm
+
+Emulated using timers that must be explicitly polled whenever Perl
+wants to dispatch "safe signals" and therefore cannot interrupt
+blocking system calls. (Win32)
+
+=item atan2
+
+Due to issues with various CPUs, math libraries, compilers, and standards,
+results for C<atan2()> may vary depending on any combination of the above.
+Perl attempts to conform to the Open Group/IEEE standards for the results
+returned from C<atan2()>, but cannot force the issue if the system Perl is
+run on does not allow it. (Tru64, HP-UX 10.20)
+
+The current version of the standards for C<atan2()> is available at
+L<http://www.opengroup.org/onlinepubs/009695399/functions/atan2.html>.
+
+=item binmode
+
+Meaningless. (S<RISC OS>)
+
+Reopens file and restores pointer; if function fails, underlying
+filehandle may be closed, or pointer may be in a different position.
+(VMS)
+
+The value returned by C<tell> may be affected after the call, and
+the filehandle may be flushed. (Win32)
+
+=item chmod
+
+Only good for changing "owner" read-write access, "group", and "other"
+bits are meaningless. (Win32)
+
+Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
+
+Access permissions are mapped onto VOS access-control list changes. (VOS)
+
+The actual permissions set depend on the value of the C<CYGWIN>
+in the SYSTEM environment settings. (Cygwin)
+
+=item chown
+
+Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
+
+Does nothing, but won't fail. (Win32)
+
+A little funky, because VOS's notion of ownership is a little funky (VOS).
+
+=item chroot
+
+Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
+
+=item crypt
+
+May not be available if library or source was not provided when building
+perl. (Win32)
+
+=item dbmclose
+
+Not implemented. (VMS, S<Plan 9>, VOS)
+
+=item dbmopen
+
+Not implemented. (VMS, S<Plan 9>, VOS)
+
+=item dump
+
+Not useful. (S<RISC OS>)
+
+Not supported. (Cygwin, Win32)
+
+Invokes VMS debugger. (VMS)
+
+=item exec
+
+Implemented via Spawn. (VM/ESA)
+
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
+
+=item exit
+
+Emulates Unix exit() (which considers C<exit 1> to indicate an error) by
+mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
+with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
+function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
+(C<1>); this mapping cannot be overridden. Any other argument to exit()
+is used directly as Perl's exit status. On VMS, unless the future
+POSIX_EXIT mode is enabled, the exit code should always be a valid
+VMS exit code and not a generic number. When the POSIX_EXIT mode is
+enabled, a generic number will be encoded in a method compatible with
+the C library _POSIX_EXIT macro so that it can be decoded by other
+programs, particularly ones written in C, like the GNV package. (VMS)
+
+=item fcntl
+
+Not implemented. (Win32)
+Some functions available based on the version of VMS. (VMS)
+
+=item flock
+
+Not implemented (VMS, S<RISC OS>, VOS).
+
+Available only on Windows NT (not on Windows 95). (Win32)
+
+=item fork
+
+Not implemented. (AmigaOS, S<RISC OS>, VM/ESA, VMS)
+
+Emulated using multiple interpreters. See L<perlfork>. (Win32)
+
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
+
+=item getlogin
+
+Not implemented. (S<RISC OS>)
+
+=item getpgrp
+
+Not implemented. (Win32, VMS, S<RISC OS>)
+
+=item getppid
+
+Not implemented. (Win32, S<RISC OS>)
+
+=item getpriority
+
+Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
+
+=item getpwnam
+
+Not implemented. (Win32)
+
+Not useful. (S<RISC OS>)
+
+=item getgrnam
+
+Not implemented. (Win32, VMS, S<RISC OS>)
+
+=item getnetbyname
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item getpwuid
+
+Not implemented. (Win32)
+
+Not useful. (S<RISC OS>)
+
+=item getgrgid
+
+Not implemented. (Win32, VMS, S<RISC OS>)
+
+=item getnetbyaddr
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item getprotobynumber
+
+=item getservbyport
+
+=item getpwent
+
+Not implemented. (Win32, VM/ESA)
+
+=item getgrent
+
+Not implemented. (Win32, VMS, VM/ESA)
+
+=item gethostbyname
+
+C<gethostbyname('localhost')> does not work everywhere: you may have
+to use C<gethostbyname('127.0.0.1')>. (S<Irix 5>)
+
+=item gethostent
+
+Not implemented. (Win32)
+
+=item getnetent
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item getprotoent
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item getservent
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item sethostent
+
+Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
+
+=item setnetent
+
+Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
+
+=item setprotoent
+
+Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
+
+=item setservent
+
+Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
+
+=item endpwent
+
+Not implemented. (MPE/iX, VM/ESA, Win32)
+
+=item endgrent
+
+Not implemented. (MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
+
+=item endhostent
+
+Not implemented. (Win32)
+
+=item endnetent
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item endprotoent
+
+Not implemented. (Win32, S<Plan 9>)
+
+=item endservent
+
+Not implemented. (S<Plan 9>, Win32)
+
+=item getsockopt SOCKET,LEVEL,OPTNAME
+
+Not implemented. (S<Plan 9>)
+
+=item glob
+
+This operator is implemented via the File::Glob extension on most
+platforms. See L<File::Glob> for portability information.
+
+=item gmtime
+
+In theory, gmtime() is reliable from -2**63 to 2**63-1. However,
+because work arounds in the implementation use floating point numbers,
+it will become inaccurate as the time gets larger. This is a bug and
+will be fixed in the future.
+
+On VOS, time values are 32-bit quantities.
+
+=item ioctl FILEHANDLE,FUNCTION,SCALAR
+
+Not implemented. (VMS)
+
+Available only for socket handles, and it does what the ioctlsocket() call
+in the Winsock API does. (Win32)
+
+Available only for socket handles. (S<RISC OS>)
+
+=item kill
+
+Not implemented, hence not useful for taint checking. (S<RISC OS>)
+
+C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
+a signal to the identified process like it does on Unix platforms.
+Instead C<kill($sig, $pid)> terminates the process identified by $pid,
+and makes it exit immediately with exit status $sig. As in Unix, if
+$sig is 0 and the specified process exists, it returns true without
+actually terminating it. (Win32)
+
+C<kill(-9, $pid)> will terminate the process specified by $pid and
+recursively all child processes owned by it. This is different from
+the Unix semantics, where the signal will be delivered to all
+processes in the same process group as the process specified by
+$pid. (Win32)
+
+Is not supported for process identification number of 0 or negative
+numbers. (VMS)
+
+=item link
+
+Not implemented. (MPE/iX, S<RISC OS>, VOS)
+
+Link count not updated because hard links are not quite that hard
+(They are sort of half-way between hard and soft links). (AmigaOS)
+
+Hard links are implemented on Win32 under NTFS only. They are
+natively supported on Windows 2000 and later. On Windows NT they
+are implemented using the Windows POSIX subsystem support and the
+Perl process will need Administrator or Backup Operator privileges
+to create hard links.
+
+Available on 64 bit OpenVMS 8.2 and later. (VMS)
+
+=item localtime
+
+localtime() has the same range as L<gmtime>, but because time zone
+rules change its accuracy for historical and future times may degrade
+but usually by no more than an hour.
+
+=item lstat
+
+Not implemented. (S<RISC OS>)
+
+Return values (especially for device and inode) may be bogus. (Win32)
+
+=item msgctl
+
+=item msgget
+
+=item msgsnd
+
+=item msgrcv
+
+Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
+
+=item open
+
+open to C<|-> and C<-|> are unsupported. (Win32, S<RISC OS>)
+
+Opening a process does not automatically flush output handles on some
+platforms. (SunOS, Solaris, HP-UX)
+
+=item readlink
+
+Not implemented. (Win32, VMS, S<RISC OS>)
+
+=item rename
+
+Can't move directories between directories on different logical volumes. (Win32)
+
+=item select
+
+Only implemented on sockets. (Win32, VMS)
+
+Only reliable on sockets. (S<RISC OS>)
+
+Note that the C<select FILEHANDLE> form is generally portable.
+
+=item semctl
+
+=item semget
+
+=item semop
+
+Not implemented. (Win32, VMS, S<RISC OS>)
+
+=item setgrent
+
+Not implemented. (MPE/iX, VMS, Win32, S<RISC OS>)
+
+=item setpgrp
+
+Not implemented. (Win32, VMS, S<RISC OS>, VOS)
+
+=item setpriority
+
+Not implemented. (Win32, VMS, S<RISC OS>, VOS)
+
+=item setpwent
+
+Not implemented. (MPE/iX, Win32, S<RISC OS>)
+
+=item setsockopt
+
+Not implemented. (S<Plan 9>)
+
+=item shmctl
+
+=item shmget
+
+=item shmread
+
+=item shmwrite
+
+Not implemented. (Win32, VMS, S<RISC OS>, VOS)
+
+=item sockatmark
+
+A relatively recent addition to socket functions, may not
+be implemented even in Unix platforms.
+
+=item socketpair
+
+Not implemented. (S<RISC OS>, VM/ESA)
+
+Available on OpenVOS Release 17.0 or later. (VOS)
+
+Available on 64 bit OpenVMS 8.2 and later. (VMS)
+
+=item stat
+
+Platforms that do not have rdev, blksize, or blocks will return these
+as '', so numeric comparison or manipulation of these fields may cause
+'not numeric' warnings.
+
+ctime not supported on UFS (S<Mac OS X>).
+
+ctime is creation time instead of inode change time (Win32).
+
+device and inode are not meaningful. (Win32)
+
+device and inode are not necessarily reliable. (VMS)
+
+mtime, atime and ctime all return the last modification time. Device and
+inode are not necessarily reliable. (S<RISC OS>)
+
+dev, rdev, blksize, and blocks are not available. inode is not
+meaningful and will differ between stat calls on the same file. (os2)
+
+some versions of cygwin when doing a stat("foo") and if not finding it
+may then attempt to stat("foo.exe") (Cygwin)
+
+On Win32 stat() needs to open the file to determine the link count
+and update attributes that may have been changed through hard links.
+Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up stat() by
+not performing this operation. (Win32)
+
+=item symlink
+
+Not implemented. (Win32, S<RISC OS>)
+
+Implemented on 64 bit VMS 8.3. VMS requires the symbolic link to be in Unix
+syntax if it is intended to resolve to a valid path.
+
+=item syscall
+
+Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
+
+=item sysopen
+
+The traditional "0", "1", and "2" MODEs are implemented with different
+numeric values on some systems. The flags exported by C<Fcntl>
+(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
+OS>, OS/390, VM/ESA)
+
+=item system
+
+As an optimization, may not call the command shell specified in
+C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
+process and immediately returns its process designator, without
+waiting for it to terminate. Return value may be used subsequently
+in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
+by setting $? to "255 << 8". C<$?> is set in a way compatible with
+Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
+as described in the documentation). (Win32)
+
+There is no shell to process metacharacters, and the native standard is
+to pass a command line terminated by "\n" "\r" or "\0" to the spawned
+program. Redirection such as C<< > foo >> is performed (if at all) by
+the run time library of the spawned program. C<system> I<list> will call
+the Unix emulation library's C<exec> emulation, which attempts to provide
+emulation of the stdin, stdout, stderr in force in the parent, providing
+the child program uses a compatible version of the emulation library.
+I<scalar> will call the native command line direct and no such emulation
+of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
+
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
+
+The return value is POSIX-like (shifted up by 8 bits), which only allows
+room for a made-up value derived from the severity bits of the native
+32-bit condition code (unless overridden by C<use vmsish 'status'>).
+If the native condition code is one that has a POSIX value encoded, the
+POSIX value will be decoded to extract the expected exit value.
+For more details see L<perlvms/$?>. (VMS)
+
+=item times
+
+"cumulative" times will be bogus. On anything other than Windows NT
+or Windows 2000, "system" time will be bogus, and "user" time is
+actually the time returned by the clock() function in the C runtime
+library. (Win32)
+
+Not useful. (S<RISC OS>)
+
+=item truncate
+
+Not implemented. (Older versions of VMS)
+
+Truncation to same-or-shorter lengths only. (VOS)
+
+If a FILEHANDLE is supplied, it must be writable and opened in append
+mode (i.e., use C<<< open(FH, '>>filename') >>>
+or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
+should not be held open elsewhere. (Win32)
+
+=item umask
+
+Returns undef where unavailable, as of version 5.005.
+
+C<umask> works but the correct permissions are set only when the file
+is finally closed. (AmigaOS)
+
+=item utime
+
+Only the modification time is updated. (S<BeOS>, VMS, S<RISC OS>)
+
+May not behave as expected. Behavior depends on the C runtime
+library's implementation of utime(), and the filesystem being
+used. The FAT filesystem typically does not support an "access
+time" field, and it may limit timestamps to a granularity of
+two seconds. (Win32)
+
+=item wait
+
+=item waitpid
+
+Can only be applied to process handles returned for processes spawned
+using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
+
+Not useful. (S<RISC OS>)
+
+=back
+
+
+=head1 Supported Platforms
+
+The following platforms are known to build Perl 5.12 (as of April 2010,
+its release date) from the standard source code distribution available
+at http://www.cpan.org/src
+
+=over
+
+=item Linux (x86, ARM, IA64)
+
+=item HP-UX
+
+=item AIX
+
+=item Win32
+
+=over
+
+=item Windows 2000
+
+=item Windows XP
+
+=item Windows Server 2003
+
+=item Windows Vista
+
+=item Windows Server 2008
+
+=item Windows 7
+
+=back
+
+=item Cygwin
+
+=item Solaris (x86, SPARC)
+
+=item OpenVMS
+
+=over
+
+=item Alpha (7.2 and later)
+
+=item I64 (8.2 and later)
+
+=back
+
+=item Symbian
+
+=item NetBSD
+
+=item FreeBSD
+
+=item Haiku
+
+=item Irix (6.5. What else?)
+
+=item OpenBSD
+
+=item Dragonfly BSD
+
+=item MirOS BSD
+
+Caveats:
+
+=over
+
+=item time_t issues that may or may not be fixed
+
+=back
+
+
+=item Symbian (Series 60 v3, 3.2 and 5 - what else?)
+
+=item Stratus VOS / OpenVOS
+
+=item AIX
+
+=back
+
+=head1 EOL Platforms (Perl 5.12)
+
+The following platforms were supported by a previous version of
+Perl but have been officially removed from Perl's source code
+as of 5.12:
+
+=over
+
+=item Atari MiNT
+
+=item Apollo Domain/OS
+
+=item Apple Mac OS 8/9
+
+=item Tenon Machten
+
+=back
+
+The following platforms may still work as of Perl 5.12, but Perl's
+developers have made an explicit decision to discontinue support for
+them:
+
+=over
+
+=item Windows 95
+
+=item Windows 98
+
+=item Windows ME
+
+=item Windows NT4
+
+=back
+
+=head1 Supported Platforms (Perl 5.8)
+
+As of July 2002 (the Perl release 5.8.0), the following platforms were
+able to build Perl from the standard source code distribution
+available at http://www.cpan.org/src/
+
+ AIX
+ BeOS
+ BSD/OS (BSDi)
+ Cygwin
+ DG/UX
+ DOS DJGPP 1)
+ DYNIX/ptx
+ EPOC R5
+ FreeBSD
+ HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
+ HP-UX
+ IRIX
+ Linux
+ Mac OS Classic
+ Mac OS X (Darwin)
+ MPE/iX
+ NetBSD
+ NetWare
+ NonStop-UX
+ ReliantUNIX (formerly SINIX)
+ OpenBSD
+ OpenVMS (formerly VMS)
+ Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
+ OS/2
+ OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
+ PowerUX
+ POSIX-BC (formerly BS2000)
+ QNX
+ Solaris
+ SunOS 4
+ SUPER-UX (NEC)
+ Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
+ UNICOS
+ UNICOS/mk
+ UTS
+ VOS
+ Win95/98/ME/2K/XP 2)
+ WinCE
+ z/OS (formerly OS/390)
+ VM/ESA
+
+ 1) in DOS mode either the DOS or OS/2 ports can be used
+ 2) compilers: Borland, MinGW (GCC), VC6
+
+The following platforms worked with the previous releases (5.6 and
+5.7), but we did not manage either to fix or to test these in time
+for the 5.8.0 release. There is a very good chance that many of these
+will work fine with the 5.8.0.
+
+ BSD/OS
+ DomainOS
+ Hurd
+ LynxOS
+ MachTen
+ PowerMAX
+ SCO SV
+ SVR4
+ Unixware
+ Windows 3.1
+
+Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
+
+ AmigaOS
+
+The following platforms have been known to build Perl from source in
+the past (5.005_03 and earlier), but we haven't been able to verify
+their status for the current release, either because the
+hardware/software platforms are rare or because we don't have an
+active champion on these platforms--or both. They used to work,
+though, so go ahead and try compiling them, and let perlbug@perl.org
+of any trouble.
+
+ 3b1
+ A/UX
+ ConvexOS
+ CX/UX
+ DC/OSx
+ DDE SMES
+ DOS EMX
+ Dynix
+ EP/IX
+ ESIX
+ FPS
+ GENIX
+ Greenhills
+ ISC
+ MachTen 68k
+ MPC
+ NEWS-OS
+ NextSTEP
+ OpenSTEP
+ Opus
+ Plan 9
+ RISC/os
+ SCO ODT/OSR
+ Stellar
+ SVR2
+ TI1500
+ TitanOS
+ Ultrix
+ Unisys Dynix
+
+The following platforms have their own source code distributions and
+binaries available via http://www.cpan.org/ports/
+
+ Perl release
+
+ OS/400 (ILE) 5.005_02
+ Tandem Guardian 5.004
+
+The following platforms have only binaries available via
+http://www.cpan.org/ports/index.html :
+
+ Perl release
+
+ Acorn RISCOS 5.005_02
+ AOS 5.002
+ LynxOS 5.004_02
+
+Although we do suggest that you always build your own Perl from
+the source code, both for maximal configurability and for security,
+in case you are in a hurry you can check
+http://www.cpan.org/ports/index.html for binary distributions.
+
+=head1 SEE ALSO
+
+L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
+L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
+L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
+L<perlmacos>, L<perlmacosx>, L<perlmpeix>,
+L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
+L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
+L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
+L<perlwin32>, and L<Win32>.
+
+=head1 AUTHORS / CONTRIBUTORS
+
+Abigail <abigail@foad.org>,
+Charles Bailey <bailey@newman.upenn.edu>,
+Graham Barr <gbarr@pobox.com>,
+Tom Christiansen <tchrist@perl.com>,
+Nicholas Clark <nick@ccl4.org>,
+Thomas Dorner <Thomas.Dorner@start.de>,
+Andy Dougherty <doughera@lafayette.edu>,
+Dominic Dunlop <domo@computer.org>,
+Neale Ferguson <neale@vma.tabnsw.com.au>,
+David J. Fiander <davidf@mks.com>,
+Paul Green <Paul.Green@stratus.com>,
+M.J.T. Guy <mjtg@cam.ac.uk>,
+Jarkko Hietaniemi <jhi@iki.fi>,
+Luther Huffman <lutherh@stratcom.com>,
+Nick Ing-Simmons <nick@ing-simmons.net>,
+Andreas J. KE<ouml>nig <a.koenig@mind.de>,
+Markus Laker <mlaker@contax.co.uk>,
+Andrew M. Langmead <aml@world.std.com>,
+Larry Moore <ljmoore@freespace.net>,
+Paul Moore <Paul.Moore@uk.origin-it.com>,
+Chris Nandor <pudge@pobox.com>,
+Matthias Neeracher <neeracher@mac.com>,
+Philip Newton <pne@cpan.org>,
+Gary Ng <71564.1743@CompuServe.COM>,
+Tom Phoenix <rootbeer@teleport.com>,
+AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
+Peter Prymmer <pvhp@forte.com>,
+Hugo van der Sanden <hv@crypt0.demon.co.uk>,
+Gurusamy Sarathy <gsar@activestate.com>,
+Paul J. Schinder <schinder@pobox.com>,
+Michael G Schwern <schwern@pobox.com>,
+Dan Sugalski <dan@sidhe.org>,
+Nathan Torkington <gnat@frii.com>.
+John Malmberg <wb8tyw@qsl.net>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlpragma.pod b/Master/tlpkg/tlperl/lib/pods/perlpragma.pod
new file mode 100644
index 00000000000..856014438e5
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlpragma.pod
@@ -0,0 +1,147 @@
+=head1 NAME
+
+perlpragma - how to write a user pragma
+
+=head1 DESCRIPTION
+
+A pragma is a module which influences some aspect of the compile time or run
+time behaviour of Perl, such as C<strict> or C<warnings>. With Perl 5.10 you
+are no longer limited to the built in pragmata; you can now create user
+pragmata that modify the behaviour of user functions within a lexical scope.
+
+=head1 A basic example
+
+For example, say you need to create a class implementing overloaded
+mathematical operators, and would like to provide your own pragma that
+functions much like C<use integer;> You'd like this code
+
+ use MyMaths;
+
+ my $l = MyMaths->new(1.2);
+ my $r = MyMaths->new(3.4);
+
+ print "A: ", $l + $r, "\n";
+
+ use myint;
+ print "B: ", $l + $r, "\n";
+
+ {
+ no myint;
+ print "C: ", $l + $r, "\n";
+ }
+
+ print "D: ", $l + $r, "\n";
+
+ no myint;
+ print "E: ", $l + $r, "\n";
+
+to give the output
+
+ A: 4.6
+ B: 4
+ C: 4.6
+ D: 4
+ E: 4.6
+
+I<i.e.>, where C<use myint;> is in effect, addition operations are forced
+to integer, whereas by default they are not, with the default behaviour being
+restored via C<no myint;>
+
+The minimal implementation of the package C<MyMaths> would be something like
+this:
+
+ package MyMaths;
+ use warnings;
+ use strict;
+ use myint();
+ use overload '+' => sub {
+ my ($l, $r) = @_;
+ # Pass 1 to check up one call level from here
+ if (myint::in_effect(1)) {
+ int($$l) + int($$r);
+ } else {
+ $$l + $$r;
+ }
+ };
+
+ sub new {
+ my ($class, $value) = @_;
+ bless \$value, $class;
+ }
+
+ 1;
+
+Note how we load the user pragma C<myint> with an empty list C<()> to
+prevent its C<import> being called.
+
+The interaction with the Perl compilation happens inside package C<myint>:
+
+ package myint;
+
+ use strict;
+ use warnings;
+
+ sub import {
+ $^H{myint} = 1;
+ }
+
+ sub unimport {
+ $^H{myint} = 0;
+ }
+
+ sub in_effect {
+ my $level = shift // 0;
+ my $hinthash = (caller($level))[10];
+ return $hinthash->{myint};
+ }
+
+ 1;
+
+As pragmata are implemented as modules, like any other module, C<use myint;>
+becomes
+
+ BEGIN {
+ require myint;
+ myint->import();
+ }
+
+and C<no myint;> is
+
+ BEGIN {
+ require myint;
+ myint->unimport();
+ }
+
+Hence the C<import> and C<unimport> routines are called at B<compile time>
+for the user's code.
+
+User pragmata store their state by writing to the magical hash C<%^H>,
+hence these two routines manipulate it. The state information in C<%^H> is
+stored in the optree, and can be retrieved read-only at runtime with C<caller()>,
+at index 10 of the list of returned results. In the example pragma, retrieval
+is encapsulated into the routine C<in_effect()>, which takes as parameter
+the number of call frames to go up to find the value of the pragma in the
+user's script. This uses C<caller()> to determine the value of
+C<$^H{myint}> when each line of the user's script was called, and
+therefore provide the correct semantics in the subroutine implementing the
+overloaded addition.
+
+=head1 Implementation details
+
+The optree is shared between threads. This means there is a possibility that
+the optree will outlive the particular thread (and therefore the interpreter
+instance) that created it, so true Perl scalars cannot be stored in the
+optree. Instead a compact form is used, which can only store values that are
+integers (signed and unsigned), strings or C<undef> - references and
+floating point values are stringified. If you need to store multiple values
+or complex structures, you should serialise them, for example with C<pack>.
+The deletion of a hash key from C<%^H> is recorded, and as ever can be
+distinguished from the existence of a key with value C<undef> with
+C<exists>.
+
+B<Don't> attempt to store references to data structures as integers which
+are retrieved via C<caller> and converted back, as this will not be threadsafe.
+Accesses would be to the structure without locking (which is not safe for
+Perl's scalars), and either the structure has to leak, or it has to be
+freed when its creating thread terminates, which may be before the optree
+referencing it is deleted, if other threads outlive it.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlqnx.pod b/Master/tlpkg/tlperl/lib/pods/perlqnx.pod
new file mode 100644
index 00000000000..0ad269a2725
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlqnx.pod
@@ -0,0 +1,143 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.qnx - Perl version 5 on QNX
+
+=head1 DESCRIPTION
+
+As of perl5.7.2 all tests pass under:
+
+ QNX 4.24G
+ Watcom 10.6 with Beta/970211.wcc.update.tar.F
+ socket3r.lib Nov21 1996.
+
+As of perl5.8.1 there is at least one test still failing.
+
+Some tests may complain under known circumstances.
+
+See below and hints/qnx.sh for more information.
+
+Under QNX 6.2.0 there are still a few tests which fail.
+See below and hints/qnx.sh for more information.
+
+=head2 Required Software for Compiling Perl on QNX4
+
+As with many unix ports, this one depends on a few "standard"
+unix utilities which are not necessarily standard for QNX4.
+
+=over 4
+
+=item /bin/sh
+
+This is used heavily by Configure and then by
+perl itself. QNX4's version is fine, but Configure
+will choke on the 16-bit version, so if you are
+running QNX 4.22, link /bin/sh to /bin32/ksh
+
+=item ar
+
+This is the standard unix library builder.
+We use wlib. With Watcom 10.6, when wlib is
+linked as "ar", it behaves like ar and all is
+fine. Under 9.5, a cover is required. One is
+included in ../qnx
+
+=item nm
+
+This is used (optionally) by configure to list
+the contents of libraries. I will generate
+a cover function on the fly in the UU directory.
+
+=item cpp
+
+Configure and perl need a way to invoke a C
+preprocessor. I have created a simple cover
+for cc which does the right thing. Without this,
+Configure will create its own wrapper which works,
+but it doesn't handle some of the command line arguments
+that perl will throw at it.
+
+=item make
+
+You really need GNU make to compile this. GNU make
+ships by default with QNX 4.23, but you can get it
+from quics for earlier versions.
+
+=back
+
+=head2 Outstanding Issues with Perl on QNX4
+
+There is no support for dynamically linked libraries in QNX4.
+
+If you wish to compile with the Socket extension, you need
+to have the TCP/IP toolkit, and you need to make sure that
+-lsocket locates the correct copy of socket3r.lib. Beware
+that the Watcom compiler ships with a stub version of
+socket3r.lib which has very little functionality. Also
+beware the order in which wlink searches directories for
+libraries. You may have /usr/lib/socket3r.lib pointing to
+the correct library, but wlink may pick up
+/usr/watcom/10.6/usr/lib/socket3r.lib instead. Make sure
+they both point to the correct library, that is,
+/usr/tcptk/current/usr/lib/socket3r.lib.
+
+The following tests may report errors under QNX4:
+
+cpan/Cwd/Cwd.t will complain if `pwd` and cwd don't give
+the same results. cwd calls `fullpath -t`, so if you
+cd `fullpath -t` before running the test, it will
+pass.
+
+lib/File/Find/taint.t will complain if '.' is in your
+PATH. The PATH test is triggered because cwd calls
+`fullpath -t`.
+
+ext/IO/lib/IO/t/io_sock.t: Subtests 14 and 22 are skipped due to
+the fact that the functionality to read back the non-blocking
+status of a socket is not implemented in QNX's TCP/IP. This has
+been reported to QNX and it may work with later versions of
+TCP/IP.
+
+t/io/tell.t: Subtest 27 is failing. We are still investigating.
+
+=head2 QNX auxiliary files
+
+The files in the "qnx" directory are:
+
+=over 4
+
+=item qnx/ar
+
+A script that emulates the standard unix archive (aka library)
+utility. Under Watcom 10.6, ar is linked to wlib and provides the
+expected interface. With Watcom 9.5, a cover function is
+required. This one is fairly crude but has proved adequate for
+compiling perl.
+
+=item qnx/cpp
+
+A script that provides C preprocessing functionality. Configure can
+generate a similar cover, but it doesn't handle all the command-line
+options that perl throws at it. This might be reasonably placed in
+/usr/local/bin.
+
+=back
+
+=head2 Outstanding issues with perl under QNX6
+
+The following tests are still failing for Perl 5.8.1 under QNX 6.2.0:
+
+ op/sprintf.........................FAILED at test 91
+ lib/Benchmark......................FAILED at test 26
+
+This is due to a bug in the C library's printf routine.
+printf("'%e'", 0. ) produces '0.000000e+0', but ANSI requires
+'0.000000e+00'. QNX has acknowledged the bug.
+
+=head1 AUTHOR
+
+Norton T. Allen (allen@huarp.harvard.edu)
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlre.pod b/Master/tlpkg/tlperl/lib/pods/perlre.pod
new file mode 100644
index 00000000000..527da4cb38a
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlre.pod
@@ -0,0 +1,2081 @@
+=head1 NAME
+X<regular expression> X<regex> X<regexp>
+
+perlre - Perl regular expressions
+
+=head1 DESCRIPTION
+
+This page describes the syntax of regular expressions in Perl.
+
+If you haven't used regular expressions before, a quick-start
+introduction is available in L<perlrequick>, and a longer tutorial
+introduction is available in L<perlretut>.
+
+For reference on how regular expressions are used in matching
+operations, plus various examples of the same, see discussions of
+C<m//>, C<s///>, C<qr//> and C<??> in L<perlop/"Regexp Quote-Like
+Operators">.
+
+
+=head2 Modifiers
+
+Matching operations can have various modifiers. Modifiers
+that relate to the interpretation of the regular expression inside
+are listed below. Modifiers that alter the way a regular expression
+is used by Perl are detailed in L<perlop/"Regexp Quote-Like Operators"> and
+L<perlop/"Gory details of parsing quoted constructs">.
+
+=over 4
+
+=item m
+X</m> X<regex, multiline> X<regexp, multiline> X<regular expression, multiline>
+
+Treat string as multiple lines. That is, change "^" and "$" from matching
+the start or end of the string to matching the start or end of any
+line anywhere within the string.
+
+=item s
+X</s> X<regex, single-line> X<regexp, single-line>
+X<regular expression, single-line>
+
+Treat string as single line. That is, change "." to match any character
+whatsoever, even a newline, which normally it would not match.
+
+Used together, as C</ms>, they let the "." match any character whatsoever,
+while still allowing "^" and "$" to match, respectively, just after
+and just before newlines within the string.
+
+=item i
+X</i> X<regex, case-insensitive> X<regexp, case-insensitive>
+X<regular expression, case-insensitive>
+
+Do case-insensitive pattern matching.
+
+If C<use locale> is in effect, the case map is taken from the current
+locale. See L<perllocale>.
+
+=item x
+X</x>
+
+Extend your pattern's legibility by permitting whitespace and comments.
+
+=item p
+X</p> X<regex, preserve> X<regexp, preserve>
+
+Preserve the string matched such that ${^PREMATCH}, ${^MATCH}, and
+${^POSTMATCH} are available for use after matching.
+
+=item g and c
+X</g> X</c>
+
+Global matching, and keep the Current position after failed matching.
+Unlike i, m, s and x, these two flags affect the way the regex is used
+rather than the regex itself. See
+L<perlretut/"Using regular expressions in Perl"> for further explanation
+of the g and c modifiers.
+
+=back
+
+These are usually written as "the C</x> modifier", even though the delimiter
+in question might not really be a slash. Any of these
+modifiers may also be embedded within the regular expression itself using
+the C<(?...)> construct. See below.
+
+The C</x> modifier itself needs a little more explanation. It tells
+the regular expression parser to ignore most whitespace that is neither
+backslashed nor within a character class. You can use this to break up
+your regular expression into (slightly) more readable parts. The C<#>
+character is also treated as a metacharacter introducing a comment,
+just as in ordinary Perl code. This also means that if you want real
+whitespace or C<#> characters in the pattern (outside a character
+class, where they are unaffected by C</x>), then you'll either have to
+escape them (using backslashes or C<\Q...\E>) or encode them using octal,
+hex, or C<\N{}> escapes. Taken together, these features go a long way towards
+making Perl's regular expressions more readable. Note that you have to
+be careful not to include the pattern delimiter in the comment--perl has
+no way of knowing you did not intend to close the pattern early. See
+the C-comment deletion code in L<perlop>. Also note that anything inside
+a C<\Q...\E> stays unaffected by C</x>. And note that C</x> doesn't affect
+whether space interpretation within a single multi-character construct. For
+example in C<\x{...}>, regardless of the C</x> modifier, there can be no
+spaces. Same for a L<quantifier|/Quantifiers> such as C<{3}> or
+C<{5,}>. Similarly, C<(?:...)> can't have a space between the C<?> and C<:>,
+but can between the C<(> and C<?>. Within any delimiters for such a
+construct, allowed spaces are not affected by C</x>, and depend on the
+construct. For example, C<\x{...}> can't have spaces because hexadecimal
+numbers don't have spaces in them. But, Unicode properties can have spaces, so
+in C<\p{...}> there can be spaces that follow the Unicode rules, for which see
+L<perluniprops/Properties accessible through \p{} and \P{}>.
+X</x>
+
+=head2 Regular Expressions
+
+=head3 Metacharacters
+
+The patterns used in Perl pattern matching evolved from those supplied in
+the Version 8 regex routines. (The routines are derived
+(distantly) from Henry Spencer's freely redistributable reimplementation
+of the V8 routines.) See L<Version 8 Regular Expressions> for
+details.
+
+In particular the following metacharacters have their standard I<egrep>-ish
+meanings:
+X<metacharacter>
+X<\> X<^> X<.> X<$> X<|> X<(> X<()> X<[> X<[]>
+
+
+ \ Quote the next metacharacter
+ ^ Match the beginning of the line
+ . Match any character (except newline)
+ $ Match the end of the line (or before newline at the end)
+ | Alternation
+ () Grouping
+ [] Bracketed Character class
+
+By default, the "^" character is guaranteed to match only the
+beginning of the string, the "$" character only the end (or before the
+newline at the end), and Perl does certain optimizations with the
+assumption that the string contains only one line. Embedded newlines
+will not be matched by "^" or "$". You may, however, wish to treat a
+string as a multi-line buffer, such that the "^" will match after any
+newline within the string (except if the newline is the last character in
+the string), and "$" will match before any newline. At the
+cost of a little more overhead, you can do this by using the /m modifier
+on the pattern match operator. (Older programs did this by setting C<$*>,
+but this practice has been removed in perl 5.9.)
+X<^> X<$> X</m>
+
+To simplify multi-line substitutions, the "." character never matches a
+newline unless you use the C</s> modifier, which in effect tells Perl to pretend
+the string is a single line--even if it isn't.
+X<.> X</s>
+
+=head3 Quantifiers
+
+The following standard quantifiers are recognized:
+X<metacharacter> X<quantifier> X<*> X<+> X<?> X<{n}> X<{n,}> X<{n,m}>
+
+ * Match 0 or more times
+ + Match 1 or more times
+ ? Match 1 or 0 times
+ {n} Match exactly n times
+ {n,} Match at least n times
+ {n,m} Match at least n but not more than m times
+
+(If a curly bracket occurs in any other context, it is treated
+as a regular character. In particular, the lower bound
+is not optional.) The "*" quantifier is equivalent to C<{0,}>, the "+"
+quantifier to C<{1,}>, and the "?" quantifier to C<{0,1}>. n and m are limited
+to non-negative integral values less than a preset limit defined when perl is built.
+This is usually 32766 on the most common platforms. The actual limit can
+be seen in the error message generated by code such as this:
+
+ $_ **= $_ , / {$_} / for 2 .. 42;
+
+By default, a quantified subpattern is "greedy", that is, it will match as
+many times as possible (given a particular starting location) while still
+allowing the rest of the pattern to match. If you want it to match the
+minimum number of times possible, follow the quantifier with a "?". Note
+that the meanings don't change, just the "greediness":
+X<metacharacter> X<greedy> X<greediness>
+X<?> X<*?> X<+?> X<??> X<{n}?> X<{n,}?> X<{n,m}?>
+
+ *? Match 0 or more times, not greedily
+ +? Match 1 or more times, not greedily
+ ?? Match 0 or 1 time, not greedily
+ {n}? Match exactly n times, not greedily
+ {n,}? Match at least n times, not greedily
+ {n,m}? Match at least n but not more than m times, not greedily
+
+By default, when a quantified subpattern does not allow the rest of the
+overall pattern to match, Perl will backtrack. However, this behaviour is
+sometimes undesirable. Thus Perl provides the "possessive" quantifier form
+as well.
+
+ *+ Match 0 or more times and give nothing back
+ ++ Match 1 or more times and give nothing back
+ ?+ Match 0 or 1 time and give nothing back
+ {n}+ Match exactly n times and give nothing back (redundant)
+ {n,}+ Match at least n times and give nothing back
+ {n,m}+ Match at least n but not more than m times and give nothing back
+
+For instance,
+
+ 'aaaa' =~ /a++a/
+
+will never match, as the C<a++> will gobble up all the C<a>'s in the
+string and won't leave any for the remaining part of the pattern. This
+feature can be extremely useful to give perl hints about where it
+shouldn't backtrack. For instance, the typical "match a double-quoted
+string" problem can be most efficiently performed when written as:
+
+ /"(?:[^"\\]++|\\.)*+"/
+
+as we know that if the final quote does not match, backtracking will not
+help. See the independent subexpression C<< (?>...) >> for more details;
+possessive quantifiers are just syntactic sugar for that construct. For
+instance the above example could also be written as follows:
+
+ /"(?>(?:(?>[^"\\]+)|\\.)*)"/
+
+=head3 Escape sequences
+
+Because patterns are processed as double quoted strings, the following
+also work:
+
+ \t tab (HT, TAB)
+ \n newline (LF, NL)
+ \r return (CR)
+ \f form feed (FF)
+ \a alarm (bell) (BEL)
+ \e escape (think troff) (ESC)
+ \033 octal char (example: ESC)
+ \x1B hex char (example: ESC)
+ \x{263a} long hex char (example: Unicode SMILEY)
+ \cK control char (example: VT)
+ \N{name} named Unicode character
+ \N{U+263D} Unicode character (example: FIRST QUARTER MOON)
+ \l lowercase next char (think vi)
+ \u uppercase next char (think vi)
+ \L lowercase till \E (think vi)
+ \U uppercase till \E (think vi)
+ \Q quote (disable) pattern metacharacters till \E
+ \E end either case modification or quoted section (think vi)
+
+Details are in L<perlop/Quote and Quote-like Operators>.
+
+=head3 Character Classes and other Special Escapes
+
+In addition, Perl defines the following:
+X<\g> X<\k> X<\K> X<backreference>
+
+ Sequence Note Description
+ [...] [1] Match a character according to the rules of the bracketed
+ character class defined by the "...". Example: [a-z]
+ matches "a" or "b" or "c" ... or "z"
+ [[:...:]] [2] Match a character according to the rules of the POSIX
+ character class "..." within the outer bracketed character
+ class. Example: [[:upper:]] matches any uppercase
+ character.
+ \w [3] Match a "word" character (alphanumeric plus "_")
+ \W [3] Match a non-"word" character
+ \s [3] Match a whitespace character
+ \S [3] Match a non-whitespace character
+ \d [3] Match a decimal digit character
+ \D [3] Match a non-digit character
+ \pP [3] Match P, named property. Use \p{Prop} for longer names.
+ \PP [3] Match non-P
+ \X [4] Match Unicode "eXtended grapheme cluster"
+ \C Match a single C-language char (octet) even if that is part
+ of a larger UTF-8 character. Thus it breaks up characters
+ into their UTF-8 bytes, so you may end up with malformed
+ pieces of UTF-8. Unsupported in lookbehind.
+ \1 [5] Backreference to a specific capture buffer or group.
+ '1' may actually be any positive integer.
+ \g1 [5] Backreference to a specific or previous group,
+ \g{-1} [5] The number may be negative indicating a relative previous
+ buffer and may optionally be wrapped in curly brackets for
+ safer parsing.
+ \g{name} [5] Named backreference
+ \k<name> [5] Named backreference
+ \K [6] Keep the stuff left of the \K, don't include it in $&
+ \N [7] Any character but \n (experimental). Not affected by /s
+ modifier
+ \v [3] Vertical whitespace
+ \V [3] Not vertical whitespace
+ \h [3] Horizontal whitespace
+ \H [3] Not horizontal whitespace
+ \R [4] Linebreak
+
+=over 4
+
+=item [1]
+
+See L<perlrecharclass/Bracketed Character Classes> for details.
+
+=item [2]
+
+See L<perlrecharclass/POSIX Character Classes> for details.
+
+=item [3]
+
+See L<perlrecharclass/Backslash sequences> for details.
+
+=item [4]
+
+See L<perlrebackslash/Misc> for details.
+
+=item [5]
+
+See L</Capture buffers> below for details.
+
+=item [6]
+
+See L</Extended Patterns> below for details.
+
+=item [7]
+
+Note that C<\N> has two meanings. When of the form C<\N{NAME}>, it matches the
+character whose name is C<NAME>; and similarly when of the form
+C<\N{U+I<wide hex char>}>, it matches the character whose Unicode ordinal is
+I<wide hex char>. Otherwise it matches any character but C<\n>.
+
+=back
+
+=head3 Assertions
+
+Perl defines the following zero-width assertions:
+X<zero-width assertion> X<assertion> X<regex, zero-width assertion>
+X<regexp, zero-width assertion>
+X<regular expression, zero-width assertion>
+X<\b> X<\B> X<\A> X<\Z> X<\z> X<\G>
+
+ \b Match a word boundary
+ \B Match except at a word boundary
+ \A Match only at beginning of string
+ \Z Match only at end of string, or before newline at the end
+ \z Match only at end of string
+ \G Match only at pos() (e.g. at the end-of-match position
+ of prior m//g)
+
+A word boundary (C<\b>) is a spot between two characters
+that has a C<\w> on one side of it and a C<\W> on the other side
+of it (in either order), counting the imaginary characters off the
+beginning and end of the string as matching a C<\W>. (Within
+character classes C<\b> represents backspace rather than a word
+boundary, just as it normally does in any double-quoted string.)
+The C<\A> and C<\Z> are just like "^" and "$", except that they
+won't match multiple times when the C</m> modifier is used, while
+"^" and "$" will match at every internal line boundary. To match
+the actual end of the string and not ignore an optional trailing
+newline, use C<\z>.
+X<\b> X<\A> X<\Z> X<\z> X</m>
+
+The C<\G> assertion can be used to chain global matches (using
+C<m//g>), as described in L<perlop/"Regexp Quote-Like Operators">.
+It is also useful when writing C<lex>-like scanners, when you have
+several patterns that you want to match against consequent substrings
+of your string, see the previous reference. The actual location
+where C<\G> will match can also be influenced by using C<pos()> as
+an lvalue: see L<perlfunc/pos>. Note that the rule for zero-length
+matches is modified somewhat, in that contents to the left of C<\G> is
+not counted when determining the length of the match. Thus the following
+will not match forever:
+X<\G>
+
+ $str = 'ABC';
+ pos($str) = 1;
+ while (/.\G/g) {
+ print $&;
+ }
+
+It will print 'A' and then terminate, as it considers the match to
+be zero-width, and thus will not match at the same position twice in a
+row.
+
+It is worth noting that C<\G> improperly used can result in an infinite
+loop. Take care when using patterns that include C<\G> in an alternation.
+
+=head3 Capture buffers
+
+The bracketing construct C<( ... )> creates capture buffers. To refer
+to the current contents of a buffer later on, within the same pattern,
+use \1 for the first, \2 for the second, and so on.
+Outside the match use "$" instead of "\". (The
+\<digit> notation works in certain circumstances outside
+the match. See L</Warning on \1 Instead of $1> below for details.)
+Referring back to another part of the match is called a
+I<backreference>.
+X<regex, capture buffer> X<regexp, capture buffer>
+X<regular expression, capture buffer> X<backreference>
+
+There is no limit to the number of captured substrings that you may
+use. However Perl also uses \10, \11, etc. as aliases for \010,
+\011, etc. (Recall that 0 means octal, so \011 is the character at
+number 9 in your coded character set; which would be the 10th character,
+a horizontal tab under ASCII.) Perl resolves this
+ambiguity by interpreting \10 as a backreference only if at least 10
+left parentheses have opened before it. Likewise \11 is a
+backreference only if at least 11 left parentheses have opened
+before it. And so on. \1 through \9 are always interpreted as
+backreferences.
+If the bracketing group did not match, the associated backreference won't
+match either. (This can happen if the bracketing group is optional, or
+in a different branch of an alternation.)
+
+X<\g{1}> X<\g{-1}> X<\g{name}> X<relative backreference> X<named backreference>
+In order to provide a safer and easier way to construct patterns using
+backreferences, Perl provides the C<\g{N}> notation (starting with perl
+5.10.0). The curly brackets are optional, however omitting them is less
+safe as the meaning of the pattern can be changed by text (such as digits)
+following it. When N is a positive integer the C<\g{N}> notation is
+exactly equivalent to using normal backreferences. When N is a negative
+integer then it is a relative backreference referring to the previous N'th
+capturing group. When the bracket form is used and N is not an integer, it
+is treated as a reference to a named buffer.
+
+Thus C<\g{-1}> refers to the last buffer, C<\g{-2}> refers to the
+buffer before that. For example:
+
+ /
+ (Y) # buffer 1
+ ( # buffer 2
+ (X) # buffer 3
+ \g{-1} # backref to buffer 3
+ \g{-3} # backref to buffer 1
+ )
+ /x
+
+and would match the same as C</(Y) ( (X) \3 \1 )/x>.
+
+Additionally, as of Perl 5.10.0 you may use named capture buffers and named
+backreferences. The notation is C<< (?<name>...) >> to declare and C<< \k<name> >>
+to reference. You may also use apostrophes instead of angle brackets to delimit the
+name; and you may use the bracketed C<< \g{name} >> backreference syntax.
+It's possible to refer to a named capture buffer by absolute and relative number as well.
+Outside the pattern, a named capture buffer is available via the C<%+> hash.
+When different buffers within the same pattern have the same name, C<$+{name}>
+and C<< \k<name> >> refer to the leftmost defined group. (Thus it's possible
+to do things with named capture buffers that would otherwise require C<(??{})>
+code to accomplish.)
+X<named capture buffer> X<regular expression, named capture buffer>
+X<%+> X<$+{name}> X<< \k<name> >>
+
+Examples:
+
+ s/^([^ ]*) *([^ ]*)/$2 $1/; # swap first two words
+
+ /(.)\1/ # find first doubled char
+ and print "'$1' is the first doubled character\n";
+
+ /(?<char>.)\k<char>/ # ... a different way
+ and print "'$+{char}' is the first doubled character\n";
+
+ /(?'char'.)\1/ # ... mix and match
+ and print "'$1' is the first doubled character\n";
+
+ if (/Time: (..):(..):(..)/) { # parse out values
+ $hours = $1;
+ $minutes = $2;
+ $seconds = $3;
+ }
+
+Several special variables also refer back to portions of the previous
+match. C<$+> returns whatever the last bracket match matched.
+C<$&> returns the entire matched string. (At one point C<$0> did
+also, but now it returns the name of the program.) C<$`> returns
+everything before the matched string. C<$'> returns everything
+after the matched string. And C<$^N> contains whatever was matched by
+the most-recently closed group (submatch). C<$^N> can be used in
+extended patterns (see below), for example to assign a submatch to a
+variable.
+X<$+> X<$^N> X<$&> X<$`> X<$'>
+
+The numbered match variables ($1, $2, $3, etc.) and the related punctuation
+set (C<$+>, C<$&>, C<$`>, C<$'>, and C<$^N>) are all dynamically scoped
+until the end of the enclosing block or until the next successful
+match, whichever comes first. (See L<perlsyn/"Compound Statements">.)
+X<$+> X<$^N> X<$&> X<$`> X<$'>
+X<$1> X<$2> X<$3> X<$4> X<$5> X<$6> X<$7> X<$8> X<$9>
+
+
+B<NOTE>: Failed matches in Perl do not reset the match variables,
+which makes it easier to write code that tests for a series of more
+specific cases and remembers the best match.
+
+B<WARNING>: Once Perl sees that you need one of C<$&>, C<$`>, or
+C<$'> anywhere in the program, it has to provide them for every
+pattern match. This may substantially slow your program. Perl
+uses the same mechanism to produce $1, $2, etc, so you also pay a
+price for each pattern that contains capturing parentheses. (To
+avoid this cost while retaining the grouping behaviour, use the
+extended regular expression C<(?: ... )> instead.) But if you never
+use C<$&>, C<$`> or C<$'>, then patterns I<without> capturing
+parentheses will not be penalized. So avoid C<$&>, C<$'>, and C<$`>
+if you can, but if you can't (and some algorithms really appreciate
+them), once you've used them once, use them at will, because you've
+already paid the price. As of 5.005, C<$&> is not so costly as the
+other two.
+X<$&> X<$`> X<$'>
+
+As a workaround for this problem, Perl 5.10.0 introduces C<${^PREMATCH}>,
+C<${^MATCH}> and C<${^POSTMATCH}>, which are equivalent to C<$`>, C<$&>
+and C<$'>, B<except> that they are only guaranteed to be defined after a
+successful match that was executed with the C</p> (preserve) modifier.
+The use of these variables incurs no global performance penalty, unlike
+their punctuation char equivalents, however at the trade-off that you
+have to tell perl when you want to use them.
+X</p> X<p modifier>
+
+=head2 Quoting metacharacters
+
+Backslashed metacharacters in Perl are alphanumeric, such as C<\b>,
+C<\w>, C<\n>. Unlike some other regular expression languages, there
+are no backslashed symbols that aren't alphanumeric. So anything
+that looks like \\, \(, \), \<, \>, \{, or \} is always
+interpreted as a literal character, not a metacharacter. This was
+once used in a common idiom to disable or quote the special meanings
+of regular expression metacharacters in a string that you want to
+use for a pattern. Simply quote all non-"word" characters:
+
+ $pattern =~ s/(\W)/\\$1/g;
+
+(If C<use locale> is set, then this depends on the current locale.)
+Today it is more common to use the quotemeta() function or the C<\Q>
+metaquoting escape sequence to disable all metacharacters' special
+meanings like this:
+
+ /$unquoted\Q$quoted\E$unquoted/
+
+Beware that if you put literal backslashes (those not inside
+interpolated variables) between C<\Q> and C<\E>, double-quotish
+backslash interpolation may lead to confusing results. If you
+I<need> to use literal backslashes within C<\Q...\E>,
+consult L<perlop/"Gory details of parsing quoted constructs">.
+
+=head2 Extended Patterns
+
+Perl also defines a consistent extension syntax for features not
+found in standard tools like B<awk> and B<lex>. The syntax is a
+pair of parentheses with a question mark as the first thing within
+the parentheses. The character after the question mark indicates
+the extension.
+
+The stability of these extensions varies widely. Some have been
+part of the core language for many years. Others are experimental
+and may change without warning or be completely removed. Check
+the documentation on an individual feature to verify its current
+status.
+
+A question mark was chosen for this and for the minimal-matching
+construct because 1) question marks are rare in older regular
+expressions, and 2) whenever you see one, you should stop and
+"question" exactly what is going on. That's psychology...
+
+=over 10
+
+=item C<(?#text)>
+X<(?#)>
+
+A comment. The text is ignored. If the C</x> modifier enables
+whitespace formatting, a simple C<#> will suffice. Note that Perl closes
+the comment as soon as it sees a C<)>, so there is no way to put a literal
+C<)> in the comment.
+
+=item C<(?pimsx-imsx)>
+X<(?)>
+
+One or more embedded pattern-match modifiers, to be turned on (or
+turned off, if preceded by C<->) for the remainder of the pattern or
+the remainder of the enclosing pattern group (if any). This is
+particularly useful for dynamic patterns, such as those read in from a
+configuration file, taken from an argument, or specified in a table
+somewhere. Consider the case where some patterns want to be case
+sensitive and some do not: The case insensitive ones merely need to
+include C<(?i)> at the front of the pattern. For example:
+
+ $pattern = "foobar";
+ if ( /$pattern/i ) { }
+
+ # more flexible:
+
+ $pattern = "(?i)foobar";
+ if ( /$pattern/ ) { }
+
+These modifiers are restored at the end of the enclosing group. For example,
+
+ ( (?i) blah ) \s+ \1
+
+will match C<blah> in any case, some spaces, and an exact (I<including the case>!)
+repetition of the previous word, assuming the C</x> modifier, and no C</i>
+modifier outside this group.
+
+These modifiers do not carry over into named subpatterns called in the
+enclosing group. In other words, a pattern such as C<((?i)(&NAME))> does not
+change the case-sensitivity of the "NAME" pattern.
+
+Note that the C<p> modifier is special in that it can only be enabled,
+not disabled, and that its presence anywhere in a pattern has a global
+effect. Thus C<(?-p)> and C<(?-p:...)> are meaningless and will warn
+when executed under C<use warnings>.
+
+=item C<(?:pattern)>
+X<(?:)>
+
+=item C<(?imsx-imsx:pattern)>
+
+This is for clustering, not capturing; it groups subexpressions like
+"()", but doesn't make backreferences as "()" does. So
+
+ @fields = split(/\b(?:a|b|c)\b/)
+
+is like
+
+ @fields = split(/\b(a|b|c)\b/)
+
+but doesn't spit out extra fields. It's also cheaper not to capture
+characters if you don't need to.
+
+Any letters between C<?> and C<:> act as flags modifiers as with
+C<(?imsx-imsx)>. For example,
+
+ /(?s-i:more.*than).*million/i
+
+is equivalent to the more verbose
+
+ /(?:(?s-i)more.*than).*million/i
+
+=item C<(?|pattern)>
+X<(?|)> X<Branch reset>
+
+This is the "branch reset" pattern, which has the special property
+that the capture buffers are numbered from the same starting point
+in each alternation branch. It is available starting from perl 5.10.0.
+
+Capture buffers are numbered from left to right, but inside this
+construct the numbering is restarted for each branch.
+
+The numbering within each branch will be as normal, and any buffers
+following this construct will be numbered as though the construct
+contained only one branch, that being the one with the most capture
+buffers in it.
+
+This construct will be useful when you want to capture one of a
+number of alternative matches.
+
+Consider the following pattern. The numbers underneath show in
+which buffer the captured content will be stored.
+
+
+ # before ---------------branch-reset----------- after
+ / ( a ) (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x
+ # 1 2 2 3 2 3 4
+
+Be careful when using the branch reset pattern in combination with
+named captures. Named captures are implemented as being aliases to
+numbered buffers holding the captures, and that interferes with the
+implementation of the branch reset pattern. If you are using named
+captures in a branch reset pattern, it's best to use the same names,
+in the same order, in each of the alternations:
+
+ /(?| (?<a> x ) (?<b> y )
+ | (?<a> z ) (?<b> w )) /x
+
+Not doing so may lead to surprises:
+
+ "12" =~ /(?| (?<a> \d+ ) | (?<b> \D+))/x;
+ say $+ {a}; # Prints '12'
+ say $+ {b}; # *Also* prints '12'.
+
+The problem here is that both the buffer named C<< a >> and the buffer
+named C<< b >> are aliases for the buffer belonging to C<< $1 >>.
+
+=item Look-Around Assertions
+X<look-around assertion> X<lookaround assertion> X<look-around> X<lookaround>
+
+Look-around assertions are zero width patterns which match a specific
+pattern without including it in C<$&>. Positive assertions match when
+their subpattern matches, negative assertions match when their subpattern
+fails. Look-behind matches text up to the current match position,
+look-ahead matches text following the current match position.
+
+=over 4
+
+=item C<(?=pattern)>
+X<(?=)> X<look-ahead, positive> X<lookahead, positive>
+
+A zero-width positive look-ahead assertion. For example, C</\w+(?=\t)/>
+matches a word followed by a tab, without including the tab in C<$&>.
+
+=item C<(?!pattern)>
+X<(?!)> X<look-ahead, negative> X<lookahead, negative>
+
+A zero-width negative look-ahead assertion. For example C</foo(?!bar)/>
+matches any occurrence of "foo" that isn't followed by "bar". Note
+however that look-ahead and look-behind are NOT the same thing. You cannot
+use this for look-behind.
+
+If you are looking for a "bar" that isn't preceded by a "foo", C</(?!foo)bar/>
+will not do what you want. That's because the C<(?!foo)> is just saying that
+the next thing cannot be "foo"--and it's not, it's a "bar", so "foobar" will
+match. You would have to do something like C</(?!foo)...bar/> for that. We
+say "like" because there's the case of your "bar" not having three characters
+before it. You could cover that this way: C</(?:(?!foo)...|^.{0,2})bar/>.
+Sometimes it's still easier just to say:
+
+ if (/bar/ && $` !~ /foo$/)
+
+For look-behind see below.
+
+=item C<(?<=pattern)> C<\K>
+X<(?<=)> X<look-behind, positive> X<lookbehind, positive> X<\K>
+
+A zero-width positive look-behind assertion. For example, C</(?<=\t)\w+/>
+matches a word that follows a tab, without including the tab in C<$&>.
+Works only for fixed-width look-behind.
+
+There is a special form of this construct, called C<\K>, which causes the
+regex engine to "keep" everything it had matched prior to the C<\K> and
+not include it in C<$&>. This effectively provides variable length
+look-behind. The use of C<\K> inside of another look-around assertion
+is allowed, but the behaviour is currently not well defined.
+
+For various reasons C<\K> may be significantly more efficient than the
+equivalent C<< (?<=...) >> construct, and it is especially useful in
+situations where you want to efficiently remove something following
+something else in a string. For instance
+
+ s/(foo)bar/$1/g;
+
+can be rewritten as the much more efficient
+
+ s/foo\Kbar//g;
+
+=item C<(?<!pattern)>
+X<(?<!)> X<look-behind, negative> X<lookbehind, negative>
+
+A zero-width negative look-behind assertion. For example C</(?<!bar)foo/>
+matches any occurrence of "foo" that does not follow "bar". Works
+only for fixed-width look-behind.
+
+=back
+
+=item C<(?'NAME'pattern)>
+
+=item C<< (?<NAME>pattern) >>
+X<< (?<NAME>) >> X<(?'NAME')> X<named capture> X<capture>
+
+A named capture buffer. Identical in every respect to normal capturing
+parentheses C<()> but for the additional fact that C<%+> or C<%-> may be
+used after a successful match to refer to a named buffer. See C<perlvar>
+for more details on the C<%+> and C<%-> hashes.
+
+If multiple distinct capture buffers have the same name then the
+$+{NAME} will refer to the leftmost defined buffer in the match.
+
+The forms C<(?'NAME'pattern)> and C<< (?<NAME>pattern) >> are equivalent.
+
+B<NOTE:> While the notation of this construct is the same as the similar
+function in .NET regexes, the behavior is not. In Perl the buffers are
+numbered sequentially regardless of being named or not. Thus in the
+pattern
+
+ /(x)(?<foo>y)(z)/
+
+$+{foo} will be the same as $2, and $3 will contain 'z' instead of
+the opposite which is what a .NET regex hacker might expect.
+
+Currently NAME is restricted to simple identifiers only.
+In other words, it must match C</^[_A-Za-z][_A-Za-z0-9]*\z/> or
+its Unicode extension (see L<utf8>),
+though it isn't extended by the locale (see L<perllocale>).
+
+B<NOTE:> In order to make things easier for programmers with experience
+with the Python or PCRE regex engines, the pattern C<< (?PE<lt>NAMEE<gt>pattern) >>
+may be used instead of C<< (?<NAME>pattern) >>; however this form does not
+support the use of single quotes as a delimiter for the name.
+
+=item C<< \k<NAME> >>
+
+=item C<< \k'NAME' >>
+
+Named backreference. Similar to numeric backreferences, except that
+the group is designated by name and not number. If multiple groups
+have the same name then it refers to the leftmost defined group in
+the current match.
+
+It is an error to refer to a name not defined by a C<< (?<NAME>) >>
+earlier in the pattern.
+
+Both forms are equivalent.
+
+B<NOTE:> In order to make things easier for programmers with experience
+with the Python or PCRE regex engines, the pattern C<< (?P=NAME) >>
+may be used instead of C<< \k<NAME> >>.
+
+=item C<(?{ code })>
+X<(?{})> X<regex, code in> X<regexp, code in> X<regular expression, code in>
+
+B<WARNING>: This extended regular expression feature is considered
+experimental, and may be changed without notice. Code executed that
+has side effects may not perform identically from version to version
+due to the effect of future optimisations in the regex engine.
+
+This zero-width assertion evaluates any embedded Perl code. It
+always succeeds, and its C<code> is not interpolated. Currently,
+the rules to determine where the C<code> ends are somewhat convoluted.
+
+This feature can be used together with the special variable C<$^N> to
+capture the results of submatches in variables without having to keep
+track of the number of nested parentheses. For example:
+
+ $_ = "The brown fox jumps over the lazy dog";
+ /the (\S+)(?{ $color = $^N }) (\S+)(?{ $animal = $^N })/i;
+ print "color = $color, animal = $animal\n";
+
+Inside the C<(?{...})> block, C<$_> refers to the string the regular
+expression is matching against. You can also use C<pos()> to know what is
+the current position of matching within this string.
+
+The C<code> is properly scoped in the following sense: If the assertion
+is backtracked (compare L<"Backtracking">), all changes introduced after
+C<local>ization are undone, so that
+
+ $_ = 'a' x 8;
+ m<
+ (?{ $cnt = 0 }) # Initialize $cnt.
+ (
+ a
+ (?{
+ local $cnt = $cnt + 1; # Update $cnt, backtracking-safe.
+ })
+ )*
+ aaaa
+ (?{ $res = $cnt }) # On success copy to non-localized
+ # location.
+ >x;
+
+will set C<$res = 4>. Note that after the match, C<$cnt> returns to the globally
+introduced value, because the scopes that restrict C<local> operators
+are unwound.
+
+This assertion may be used as a C<(?(condition)yes-pattern|no-pattern)>
+switch. If I<not> used in this way, the result of evaluation of
+C<code> is put into the special variable C<$^R>. This happens
+immediately, so C<$^R> can be used from other C<(?{ code })> assertions
+inside the same regular expression.
+
+The assignment to C<$^R> above is properly localized, so the old
+value of C<$^R> is restored if the assertion is backtracked; compare
+L<"Backtracking">.
+
+For reasons of security, this construct is forbidden if the regular
+expression involves run-time interpolation of variables, unless the
+perilous C<use re 'eval'> pragma has been used (see L<re>), or the
+variables contain results of C<qr//> operator (see
+L<perlop/"qr/STRINGE<sol>msixpo">).
+
+This restriction is due to the wide-spread and remarkably convenient
+custom of using run-time determined strings as patterns. For example:
+
+ $re = <>;
+ chomp $re;
+ $string =~ /$re/;
+
+Before Perl knew how to execute interpolated code within a pattern,
+this operation was completely safe from a security point of view,
+although it could raise an exception from an illegal pattern. If
+you turn on the C<use re 'eval'>, though, it is no longer secure,
+so you should only do so if you are also using taint checking.
+Better yet, use the carefully constrained evaluation within a Safe
+compartment. See L<perlsec> for details about both these mechanisms.
+
+B<WARNING>: Use of lexical (C<my>) variables in these blocks is
+broken. The result is unpredictable and will make perl unstable. The
+workaround is to use global (C<our>) variables.
+
+B<WARNING>: Because Perl's regex engine is currently not re-entrant,
+interpolated code may not invoke the regex engine either directly with
+C<m//> or C<s///>), or indirectly with functions such as
+C<split>. Invoking the regex engine in these blocks will make perl
+unstable.
+
+=item C<(??{ code })>
+X<(??{})>
+X<regex, postponed> X<regexp, postponed> X<regular expression, postponed>
+
+B<WARNING>: This extended regular expression feature is considered
+experimental, and may be changed without notice. Code executed that
+has side effects may not perform identically from version to version
+due to the effect of future optimisations in the regex engine.
+
+This is a "postponed" regular subexpression. The C<code> is evaluated
+at run time, at the moment this subexpression may match. The result
+of evaluation is considered as a regular expression and matched as
+if it were inserted instead of this construct. Note that this means
+that the contents of capture buffers defined inside an eval'ed pattern
+are not available outside of the pattern, and vice versa, there is no
+way for the inner pattern to refer to a capture buffer defined outside.
+Thus,
+
+ ('a' x 100)=~/(??{'(.)' x 100})/
+
+B<will> match, it will B<not> set $1.
+
+The C<code> is not interpolated. As before, the rules to determine
+where the C<code> ends are currently somewhat convoluted.
+
+The following pattern matches a parenthesized group:
+
+ $re = qr{
+ \(
+ (?:
+ (?> [^()]+ ) # Non-parens without backtracking
+ |
+ (??{ $re }) # Group with matching parens
+ )*
+ \)
+ }x;
+
+See also C<(?PARNO)> for a different, more efficient way to accomplish
+the same task.
+
+For reasons of security, this construct is forbidden if the regular
+expression involves run-time interpolation of variables, unless the
+perilous C<use re 'eval'> pragma has been used (see L<re>), or the
+variables contain results of C<qr//> operator (see
+L<perlop/"qrE<sol>STRINGE<sol>msixpo">).
+
+Because perl's regex engine is not currently re-entrant, delayed
+code may not invoke the regex engine either directly with C<m//> or C<s///>),
+or indirectly with functions such as C<split>.
+
+Recursing deeper than 50 times without consuming any input string will
+result in a fatal error. The maximum depth is compiled into perl, so
+changing it requires a custom build.
+
+=item C<(?PARNO)> C<(?-PARNO)> C<(?+PARNO)> C<(?R)> C<(?0)>
+X<(?PARNO)> X<(?1)> X<(?R)> X<(?0)> X<(?-1)> X<(?+1)> X<(?-PARNO)> X<(?+PARNO)>
+X<regex, recursive> X<regexp, recursive> X<regular expression, recursive>
+X<regex, relative recursion>
+
+Similar to C<(??{ code })> except it does not involve compiling any code,
+instead it treats the contents of a capture buffer as an independent
+pattern that must match at the current position. Capture buffers
+contained by the pattern will have the value as determined by the
+outermost recursion.
+
+PARNO is a sequence of digits (not starting with 0) whose value reflects
+the paren-number of the capture buffer to recurse to. C<(?R)> recurses to
+the beginning of the whole pattern. C<(?0)> is an alternate syntax for
+C<(?R)>. If PARNO is preceded by a plus or minus sign then it is assumed
+to be relative, with negative numbers indicating preceding capture buffers
+and positive ones following. Thus C<(?-1)> refers to the most recently
+declared buffer, and C<(?+1)> indicates the next buffer to be declared.
+Note that the counting for relative recursion differs from that of
+relative backreferences, in that with recursion unclosed buffers B<are>
+included.
+
+The following pattern matches a function foo() which may contain
+balanced parentheses as the argument.
+
+ $re = qr{ ( # paren group 1 (full function)
+ foo
+ ( # paren group 2 (parens)
+ \(
+ ( # paren group 3 (contents of parens)
+ (?:
+ (?> [^()]+ ) # Non-parens without backtracking
+ |
+ (?2) # Recurse to start of paren group 2
+ )*
+ )
+ \)
+ )
+ )
+ }x;
+
+If the pattern was used as follows
+
+ 'foo(bar(baz)+baz(bop))'=~/$re/
+ and print "\$1 = $1\n",
+ "\$2 = $2\n",
+ "\$3 = $3\n";
+
+the output produced should be the following:
+
+ $1 = foo(bar(baz)+baz(bop))
+ $2 = (bar(baz)+baz(bop))
+ $3 = bar(baz)+baz(bop)
+
+If there is no corresponding capture buffer defined, then it is a
+fatal error. Recursing deeper than 50 times without consuming any input
+string will also result in a fatal error. The maximum depth is compiled
+into perl, so changing it requires a custom build.
+
+The following shows how using negative indexing can make it
+easier to embed recursive patterns inside of a C<qr//> construct
+for later use:
+
+ my $parens = qr/(\((?:[^()]++|(?-1))*+\))/;
+ if (/foo $parens \s+ + \s+ bar $parens/x) {
+ # do something here...
+ }
+
+B<Note> that this pattern does not behave the same way as the equivalent
+PCRE or Python construct of the same form. In Perl you can backtrack into
+a recursed group, in PCRE and Python the recursed into group is treated
+as atomic. Also, modifiers are resolved at compile time, so constructs
+like (?i:(?1)) or (?:(?i)(?1)) do not affect how the sub-pattern will
+be processed.
+
+=item C<(?&NAME)>
+X<(?&NAME)>
+
+Recurse to a named subpattern. Identical to C<(?PARNO)> except that the
+parenthesis to recurse to is determined by name. If multiple parentheses have
+the same name, then it recurses to the leftmost.
+
+It is an error to refer to a name that is not declared somewhere in the
+pattern.
+
+B<NOTE:> In order to make things easier for programmers with experience
+with the Python or PCRE regex engines the pattern C<< (?P>NAME) >>
+may be used instead of C<< (?&NAME) >>.
+
+=item C<(?(condition)yes-pattern|no-pattern)>
+X<(?()>
+
+=item C<(?(condition)yes-pattern)>
+
+Conditional expression. C<(condition)> should be either an integer in
+parentheses (which is valid if the corresponding pair of parentheses
+matched), a look-ahead/look-behind/evaluate zero-width assertion, a
+name in angle brackets or single quotes (which is valid if a buffer
+with the given name matched), or the special symbol (R) (true when
+evaluated inside of recursion or eval). Additionally the R may be
+followed by a number, (which will be true when evaluated when recursing
+inside of the appropriate group), or by C<&NAME>, in which case it will
+be true only when evaluated during recursion in the named group.
+
+Here's a summary of the possible predicates:
+
+=over 4
+
+=item (1) (2) ...
+
+Checks if the numbered capturing buffer has matched something.
+
+=item (<NAME>) ('NAME')
+
+Checks if a buffer with the given name has matched something.
+
+=item (?{ CODE })
+
+Treats the code block as the condition.
+
+=item (R)
+
+Checks if the expression has been evaluated inside of recursion.
+
+=item (R1) (R2) ...
+
+Checks if the expression has been evaluated while executing directly
+inside of the n-th capture group. This check is the regex equivalent of
+
+ if ((caller(0))[3] eq 'subname') { ... }
+
+In other words, it does not check the full recursion stack.
+
+=item (R&NAME)
+
+Similar to C<(R1)>, this predicate checks to see if we're executing
+directly inside of the leftmost group with a given name (this is the same
+logic used by C<(?&NAME)> to disambiguate). It does not check the full
+stack, but only the name of the innermost active recursion.
+
+=item (DEFINE)
+
+In this case, the yes-pattern is never directly executed, and no
+no-pattern is allowed. Similar in spirit to C<(?{0})> but more efficient.
+See below for details.
+
+=back
+
+For example:
+
+ m{ ( \( )?
+ [^()]+
+ (?(1) \) )
+ }x
+
+matches a chunk of non-parentheses, possibly included in parentheses
+themselves.
+
+A special form is the C<(DEFINE)> predicate, which never executes directly
+its yes-pattern, and does not allow a no-pattern. This allows to define
+subpatterns which will be executed only by using the recursion mechanism.
+This way, you can define a set of regular expression rules that can be
+bundled into any pattern you choose.
+
+It is recommended that for this usage you put the DEFINE block at the
+end of the pattern, and that you name any subpatterns defined within it.
+
+Also, it's worth noting that patterns defined this way probably will
+not be as efficient, as the optimiser is not very clever about
+handling them.
+
+An example of how this might be used is as follows:
+
+ /(?<NAME>(?&NAME_PAT))(?<ADDR>(?&ADDRESS_PAT))
+ (?(DEFINE)
+ (?<NAME_PAT>....)
+ (?<ADRESS_PAT>....)
+ )/x
+
+Note that capture buffers matched inside of recursion are not accessible
+after the recursion returns, so the extra layer of capturing buffers is
+necessary. Thus C<$+{NAME_PAT}> would not be defined even though
+C<$+{NAME}> would be.
+
+=item C<< (?>pattern) >>
+X<backtrack> X<backtracking> X<atomic> X<possessive>
+
+An "independent" subexpression, one which matches the substring
+that a I<standalone> C<pattern> would match if anchored at the given
+position, and it matches I<nothing other than this substring>. This
+construct is useful for optimizations of what would otherwise be
+"eternal" matches, because it will not backtrack (see L<"Backtracking">).
+It may also be useful in places where the "grab all you can, and do not
+give anything back" semantic is desirable.
+
+For example: C<< ^(?>a*)ab >> will never match, since C<< (?>a*) >>
+(anchored at the beginning of string, as above) will match I<all>
+characters C<a> at the beginning of string, leaving no C<a> for
+C<ab> to match. In contrast, C<a*ab> will match the same as C<a+b>,
+since the match of the subgroup C<a*> is influenced by the following
+group C<ab> (see L<"Backtracking">). In particular, C<a*> inside
+C<a*ab> will match fewer characters than a standalone C<a*>, since
+this makes the tail match.
+
+An effect similar to C<< (?>pattern) >> may be achieved by writing
+C<(?=(pattern))\1>. This matches the same substring as a standalone
+C<a+>, and the following C<\1> eats the matched string; it therefore
+makes a zero-length assertion into an analogue of C<< (?>...) >>.
+(The difference between these two constructs is that the second one
+uses a capturing group, thus shifting ordinals of backreferences
+in the rest of a regular expression.)
+
+Consider this pattern:
+
+ m{ \(
+ (
+ [^()]+ # x+
+ |
+ \( [^()]* \)
+ )+
+ \)
+ }x
+
+That will efficiently match a nonempty group with matching parentheses
+two levels deep or less. However, if there is no such group, it
+will take virtually forever on a long string. That's because there
+are so many different ways to split a long string into several
+substrings. This is what C<(.+)+> is doing, and C<(.+)+> is similar
+to a subpattern of the above pattern. Consider how the pattern
+above detects no-match on C<((()aaaaaaaaaaaaaaaaaa> in several
+seconds, but that each extra letter doubles this time. This
+exponential performance will make it appear that your program has
+hung. However, a tiny change to this pattern
+
+ m{ \(
+ (
+ (?> [^()]+ ) # change x+ above to (?> x+ )
+ |
+ \( [^()]* \)
+ )+
+ \)
+ }x
+
+which uses C<< (?>...) >> matches exactly when the one above does (verifying
+this yourself would be a productive exercise), but finishes in a fourth
+the time when used on a similar string with 1000000 C<a>s. Be aware,
+however, that this pattern currently triggers a warning message under
+the C<use warnings> pragma or B<-w> switch saying it
+C<"matches null string many times in regex">.
+
+On simple groups, such as the pattern C<< (?> [^()]+ ) >>, a comparable
+effect may be achieved by negative look-ahead, as in C<[^()]+ (?! [^()] )>.
+This was only 4 times slower on a string with 1000000 C<a>s.
+
+The "grab all you can, and do not give anything back" semantic is desirable
+in many situations where on the first sight a simple C<()*> looks like
+the correct solution. Suppose we parse text with comments being delimited
+by C<#> followed by some optional (horizontal) whitespace. Contrary to
+its appearance, C<#[ \t]*> I<is not> the correct subexpression to match
+the comment delimiter, because it may "give up" some whitespace if
+the remainder of the pattern can be made to match that way. The correct
+answer is either one of these:
+
+ (?>#[ \t]*)
+ #[ \t]*(?![ \t])
+
+For example, to grab non-empty comments into $1, one should use either
+one of these:
+
+ / (?> \# [ \t]* ) ( .+ ) /x;
+ / \# [ \t]* ( [^ \t] .* ) /x;
+
+Which one you pick depends on which of these expressions better reflects
+the above specification of comments.
+
+In some literature this construct is called "atomic matching" or
+"possessive matching".
+
+Possessive quantifiers are equivalent to putting the item they are applied
+to inside of one of these constructs. The following equivalences apply:
+
+ Quantifier Form Bracketing Form
+ --------------- ---------------
+ PAT*+ (?>PAT*)
+ PAT++ (?>PAT+)
+ PAT?+ (?>PAT?)
+ PAT{min,max}+ (?>PAT{min,max})
+
+=back
+
+=head2 Special Backtracking Control Verbs
+
+B<WARNING:> These patterns are experimental and subject to change or
+removal in a future version of Perl. Their usage in production code should
+be noted to avoid problems during upgrades.
+
+These special patterns are generally of the form C<(*VERB:ARG)>. Unless
+otherwise stated the ARG argument is optional; in some cases, it is
+forbidden.
+
+Any pattern containing a special backtracking verb that allows an argument
+has the special behaviour that when executed it sets the current package's
+C<$REGERROR> and C<$REGMARK> variables. When doing so the following
+rules apply:
+
+On failure, the C<$REGERROR> variable will be set to the ARG value of the
+verb pattern, if the verb was involved in the failure of the match. If the
+ARG part of the pattern was omitted, then C<$REGERROR> will be set to the
+name of the last C<(*MARK:NAME)> pattern executed, or to TRUE if there was
+none. Also, the C<$REGMARK> variable will be set to FALSE.
+
+On a successful match, the C<$REGERROR> variable will be set to FALSE, and
+the C<$REGMARK> variable will be set to the name of the last
+C<(*MARK:NAME)> pattern executed. See the explanation for the
+C<(*MARK:NAME)> verb below for more details.
+
+B<NOTE:> C<$REGERROR> and C<$REGMARK> are not magic variables like C<$1>
+and most other regex related variables. They are not local to a scope, nor
+readonly, but instead are volatile package variables similar to C<$AUTOLOAD>.
+Use C<local> to localize changes to them to a specific scope if necessary.
+
+If a pattern does not contain a special backtracking verb that allows an
+argument, then C<$REGERROR> and C<$REGMARK> are not touched at all.
+
+=over 4
+
+=item Verbs that take an argument
+
+=over 4
+
+=item C<(*PRUNE)> C<(*PRUNE:NAME)>
+X<(*PRUNE)> X<(*PRUNE:NAME)>
+
+This zero-width pattern prunes the backtracking tree at the current point
+when backtracked into on failure. Consider the pattern C<A (*PRUNE) B>,
+where A and B are complex patterns. Until the C<(*PRUNE)> verb is reached,
+A may backtrack as necessary to match. Once it is reached, matching
+continues in B, which may also backtrack as necessary; however, should B
+not match, then no further backtracking will take place, and the pattern
+will fail outright at the current starting position.
+
+The following example counts all the possible matching strings in a
+pattern (without actually matching any of them).
+
+ 'aaab' =~ /a+b?(?{print "$&\n"; $count++})(*FAIL)/;
+ print "Count=$count\n";
+
+which produces:
+
+ aaab
+ aaa
+ aa
+ a
+ aab
+ aa
+ a
+ ab
+ a
+ Count=9
+
+If we add a C<(*PRUNE)> before the count like the following
+
+ 'aaab' =~ /a+b?(*PRUNE)(?{print "$&\n"; $count++})(*FAIL)/;
+ print "Count=$count\n";
+
+we prevent backtracking and find the count of the longest matching
+at each matching starting point like so:
+
+ aaab
+ aab
+ ab
+ Count=3
+
+Any number of C<(*PRUNE)> assertions may be used in a pattern.
+
+See also C<< (?>pattern) >> and possessive quantifiers for other ways to
+control backtracking. In some cases, the use of C<(*PRUNE)> can be
+replaced with a C<< (?>pattern) >> with no functional difference; however,
+C<(*PRUNE)> can be used to handle cases that cannot be expressed using a
+C<< (?>pattern) >> alone.
+
+
+=item C<(*SKIP)> C<(*SKIP:NAME)>
+X<(*SKIP)>
+
+This zero-width pattern is similar to C<(*PRUNE)>, except that on
+failure it also signifies that whatever text that was matched leading up
+to the C<(*SKIP)> pattern being executed cannot be part of I<any> match
+of this pattern. This effectively means that the regex engine "skips" forward
+to this position on failure and tries to match again, (assuming that
+there is sufficient room to match).
+
+The name of the C<(*SKIP:NAME)> pattern has special significance. If a
+C<(*MARK:NAME)> was encountered while matching, then it is that position
+which is used as the "skip point". If no C<(*MARK)> of that name was
+encountered, then the C<(*SKIP)> operator has no effect. When used
+without a name the "skip point" is where the match point was when
+executing the (*SKIP) pattern.
+
+Compare the following to the examples in C<(*PRUNE)>, note the string
+is twice as long:
+
+ 'aaabaaab' =~ /a+b?(*SKIP)(?{print "$&\n"; $count++})(*FAIL)/;
+ print "Count=$count\n";
+
+outputs
+
+ aaab
+ aaab
+ Count=2
+
+Once the 'aaab' at the start of the string has matched, and the C<(*SKIP)>
+executed, the next starting point will be where the cursor was when the
+C<(*SKIP)> was executed.
+
+=item C<(*MARK:NAME)> C<(*:NAME)>
+X<(*MARK)> C<(*MARK:NAME)> C<(*:NAME)>
+
+This zero-width pattern can be used to mark the point reached in a string
+when a certain part of the pattern has been successfully matched. This
+mark may be given a name. A later C<(*SKIP)> pattern will then skip
+forward to that point if backtracked into on failure. Any number of
+C<(*MARK)> patterns are allowed, and the NAME portion may be duplicated.
+
+In addition to interacting with the C<(*SKIP)> pattern, C<(*MARK:NAME)>
+can be used to "label" a pattern branch, so that after matching, the
+program can determine which branches of the pattern were involved in the
+match.
+
+When a match is successful, the C<$REGMARK> variable will be set to the
+name of the most recently executed C<(*MARK:NAME)> that was involved
+in the match.
+
+This can be used to determine which branch of a pattern was matched
+without using a separate capture buffer for each branch, which in turn
+can result in a performance improvement, as perl cannot optimize
+C</(?:(x)|(y)|(z))/> as efficiently as something like
+C</(?:x(*MARK:x)|y(*MARK:y)|z(*MARK:z))/>.
+
+When a match has failed, and unless another verb has been involved in
+failing the match and has provided its own name to use, the C<$REGERROR>
+variable will be set to the name of the most recently executed
+C<(*MARK:NAME)>.
+
+See C<(*SKIP)> for more details.
+
+As a shortcut C<(*MARK:NAME)> can be written C<(*:NAME)>.
+
+=item C<(*THEN)> C<(*THEN:NAME)>
+
+This is similar to the "cut group" operator C<::> from Perl 6. Like
+C<(*PRUNE)>, this verb always matches, and when backtracked into on
+failure, it causes the regex engine to try the next alternation in the
+innermost enclosing group (capturing or otherwise).
+
+Its name comes from the observation that this operation combined with the
+alternation operator (C<|>) can be used to create what is essentially a
+pattern-based if/then/else block:
+
+ ( COND (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ )
+
+Note that if this operator is used and NOT inside of an alternation then
+it acts exactly like the C<(*PRUNE)> operator.
+
+ / A (*PRUNE) B /
+
+is the same as
+
+ / A (*THEN) B /
+
+but
+
+ / ( A (*THEN) B | C (*THEN) D ) /
+
+is not the same as
+
+ / ( A (*PRUNE) B | C (*PRUNE) D ) /
+
+as after matching the A but failing on the B the C<(*THEN)> verb will
+backtrack and try C; but the C<(*PRUNE)> verb will simply fail.
+
+=item C<(*COMMIT)>
+X<(*COMMIT)>
+
+This is the Perl 6 "commit pattern" C<< <commit> >> or C<:::>. It's a
+zero-width pattern similar to C<(*SKIP)>, except that when backtracked
+into on failure it causes the match to fail outright. No further attempts
+to find a valid match by advancing the start pointer will occur again.
+For example,
+
+ 'aaabaaab' =~ /a+b?(*COMMIT)(?{print "$&\n"; $count++})(*FAIL)/;
+ print "Count=$count\n";
+
+outputs
+
+ aaab
+ Count=1
+
+In other words, once the C<(*COMMIT)> has been entered, and if the pattern
+does not match, the regex engine will not try any further matching on the
+rest of the string.
+
+=back
+
+=item Verbs without an argument
+
+=over 4
+
+=item C<(*FAIL)> C<(*F)>
+X<(*FAIL)> X<(*F)>
+
+This pattern matches nothing and always fails. It can be used to force the
+engine to backtrack. It is equivalent to C<(?!)>, but easier to read. In
+fact, C<(?!)> gets optimised into C<(*FAIL)> internally.
+
+It is probably useful only when combined with C<(?{})> or C<(??{})>.
+
+=item C<(*ACCEPT)>
+X<(*ACCEPT)>
+
+B<WARNING:> This feature is highly experimental. It is not recommended
+for production code.
+
+This pattern matches nothing and causes the end of successful matching at
+the point at which the C<(*ACCEPT)> pattern was encountered, regardless of
+whether there is actually more to match in the string. When inside of a
+nested pattern, such as recursion, or in a subpattern dynamically generated
+via C<(??{})>, only the innermost pattern is ended immediately.
+
+If the C<(*ACCEPT)> is inside of capturing buffers then the buffers are
+marked as ended at the point at which the C<(*ACCEPT)> was encountered.
+For instance:
+
+ 'AB' =~ /(A (A|B(*ACCEPT)|C) D)(E)/x;
+
+will match, and C<$1> will be C<AB> and C<$2> will be C<B>, C<$3> will not
+be set. If another branch in the inner parentheses were matched, such as in the
+string 'ACDE', then the C<D> and C<E> would have to be matched as well.
+
+=back
+
+=back
+
+=head2 Backtracking
+X<backtrack> X<backtracking>
+
+NOTE: This section presents an abstract approximation of regular
+expression behavior. For a more rigorous (and complicated) view of
+the rules involved in selecting a match among possible alternatives,
+see L<Combining RE Pieces>.
+
+A fundamental feature of regular expression matching involves the
+notion called I<backtracking>, which is currently used (when needed)
+by all regular non-possessive expression quantifiers, namely C<*>, C<*?>, C<+>,
+C<+?>, C<{n,m}>, and C<{n,m}?>. Backtracking is often optimized
+internally, but the general principle outlined here is valid.
+
+For a regular expression to match, the I<entire> regular expression must
+match, not just part of it. So if the beginning of a pattern containing a
+quantifier succeeds in a way that causes later parts in the pattern to
+fail, the matching engine backs up and recalculates the beginning
+part--that's why it's called backtracking.
+
+Here is an example of backtracking: Let's say you want to find the
+word following "foo" in the string "Food is on the foo table.":
+
+ $_ = "Food is on the foo table.";
+ if ( /\b(foo)\s+(\w+)/i ) {
+ print "$2 follows $1.\n";
+ }
+
+When the match runs, the first part of the regular expression (C<\b(foo)>)
+finds a possible match right at the beginning of the string, and loads up
+$1 with "Foo". However, as soon as the matching engine sees that there's
+no whitespace following the "Foo" that it had saved in $1, it realizes its
+mistake and starts over again one character after where it had the
+tentative match. This time it goes all the way until the next occurrence
+of "foo". The complete regular expression matches this time, and you get
+the expected output of "table follows foo."
+
+Sometimes minimal matching can help a lot. Imagine you'd like to match
+everything between "foo" and "bar". Initially, you write something
+like this:
+
+ $_ = "The food is under the bar in the barn.";
+ if ( /foo(.*)bar/ ) {
+ print "got <$1>\n";
+ }
+
+Which perhaps unexpectedly yields:
+
+ got <d is under the bar in the >
+
+That's because C<.*> was greedy, so you get everything between the
+I<first> "foo" and the I<last> "bar". Here it's more effective
+to use minimal matching to make sure you get the text between a "foo"
+and the first "bar" thereafter.
+
+ if ( /foo(.*?)bar/ ) { print "got <$1>\n" }
+ got <d is under the >
+
+Here's another example. Let's say you'd like to match a number at the end
+of a string, and you also want to keep the preceding part of the match.
+So you write this:
+
+ $_ = "I have 2 numbers: 53147";
+ if ( /(.*)(\d*)/ ) { # Wrong!
+ print "Beginning is <$1>, number is <$2>.\n";
+ }
+
+That won't work at all, because C<.*> was greedy and gobbled up the
+whole string. As C<\d*> can match on an empty string the complete
+regular expression matched successfully.
+
+ Beginning is <I have 2 numbers: 53147>, number is <>.
+
+Here are some variants, most of which don't work:
+
+ $_ = "I have 2 numbers: 53147";
+ @pats = qw{
+ (.*)(\d*)
+ (.*)(\d+)
+ (.*?)(\d*)
+ (.*?)(\d+)
+ (.*)(\d+)$
+ (.*?)(\d+)$
+ (.*)\b(\d+)$
+ (.*\D)(\d+)$
+ };
+
+ for $pat (@pats) {
+ printf "%-12s ", $pat;
+ if ( /$pat/ ) {
+ print "<$1> <$2>\n";
+ } else {
+ print "FAIL\n";
+ }
+ }
+
+That will print out:
+
+ (.*)(\d*) <I have 2 numbers: 53147> <>
+ (.*)(\d+) <I have 2 numbers: 5314> <7>
+ (.*?)(\d*) <> <>
+ (.*?)(\d+) <I have > <2>
+ (.*)(\d+)$ <I have 2 numbers: 5314> <7>
+ (.*?)(\d+)$ <I have 2 numbers: > <53147>
+ (.*)\b(\d+)$ <I have 2 numbers: > <53147>
+ (.*\D)(\d+)$ <I have 2 numbers: > <53147>
+
+As you see, this can be a bit tricky. It's important to realize that a
+regular expression is merely a set of assertions that gives a definition
+of success. There may be 0, 1, or several different ways that the
+definition might succeed against a particular string. And if there are
+multiple ways it might succeed, you need to understand backtracking to
+know which variety of success you will achieve.
+
+When using look-ahead assertions and negations, this can all get even
+trickier. Imagine you'd like to find a sequence of non-digits not
+followed by "123". You might try to write that as
+
+ $_ = "ABC123";
+ if ( /^\D*(?!123)/ ) { # Wrong!
+ print "Yup, no 123 in $_\n";
+ }
+
+But that isn't going to match; at least, not the way you're hoping. It
+claims that there is no 123 in the string. Here's a clearer picture of
+why that pattern matches, contrary to popular expectations:
+
+ $x = 'ABC123';
+ $y = 'ABC445';
+
+ print "1: got $1\n" if $x =~ /^(ABC)(?!123)/;
+ print "2: got $1\n" if $y =~ /^(ABC)(?!123)/;
+
+ print "3: got $1\n" if $x =~ /^(\D*)(?!123)/;
+ print "4: got $1\n" if $y =~ /^(\D*)(?!123)/;
+
+This prints
+
+ 2: got ABC
+ 3: got AB
+ 4: got ABC
+
+You might have expected test 3 to fail because it seems to a more
+general purpose version of test 1. The important difference between
+them is that test 3 contains a quantifier (C<\D*>) and so can use
+backtracking, whereas test 1 will not. What's happening is
+that you've asked "Is it true that at the start of $x, following 0 or more
+non-digits, you have something that's not 123?" If the pattern matcher had
+let C<\D*> expand to "ABC", this would have caused the whole pattern to
+fail.
+
+The search engine will initially match C<\D*> with "ABC". Then it will
+try to match C<(?!123> with "123", which fails. But because
+a quantifier (C<\D*>) has been used in the regular expression, the
+search engine can backtrack and retry the match differently
+in the hope of matching the complete regular expression.
+
+The pattern really, I<really> wants to succeed, so it uses the
+standard pattern back-off-and-retry and lets C<\D*> expand to just "AB" this
+time. Now there's indeed something following "AB" that is not
+"123". It's "C123", which suffices.
+
+We can deal with this by using both an assertion and a negation.
+We'll say that the first part in $1 must be followed both by a digit
+and by something that's not "123". Remember that the look-aheads
+are zero-width expressions--they only look, but don't consume any
+of the string in their match. So rewriting this way produces what
+you'd expect; that is, case 5 will fail, but case 6 succeeds:
+
+ print "5: got $1\n" if $x =~ /^(\D*)(?=\d)(?!123)/;
+ print "6: got $1\n" if $y =~ /^(\D*)(?=\d)(?!123)/;
+
+ 6: got ABC
+
+In other words, the two zero-width assertions next to each other work as though
+they're ANDed together, just as you'd use any built-in assertions: C</^$/>
+matches only if you're at the beginning of the line AND the end of the
+line simultaneously. The deeper underlying truth is that juxtaposition in
+regular expressions always means AND, except when you write an explicit OR
+using the vertical bar. C</ab/> means match "a" AND (then) match "b",
+although the attempted matches are made at different positions because "a"
+is not a zero-width assertion, but a one-width assertion.
+
+B<WARNING>: Particularly complicated regular expressions can take
+exponential time to solve because of the immense number of possible
+ways they can use backtracking to try for a match. For example, without
+internal optimizations done by the regular expression engine, this will
+take a painfully long time to run:
+
+ 'aaaaaaaaaaaa' =~ /((a{0,5}){0,5})*[c]/
+
+And if you used C<*>'s in the internal groups instead of limiting them
+to 0 through 5 matches, then it would take forever--or until you ran
+out of stack space. Moreover, these internal optimizations are not
+always applicable. For example, if you put C<{0,5}> instead of C<*>
+on the external group, no current optimization is applicable, and the
+match takes a long time to finish.
+
+A powerful tool for optimizing such beasts is what is known as an
+"independent group",
+which does not backtrack (see L<C<< (?>pattern) >>>). Note also that
+zero-length look-ahead/look-behind assertions will not backtrack to make
+the tail match, since they are in "logical" context: only
+whether they match is considered relevant. For an example
+where side-effects of look-ahead I<might> have influenced the
+following match, see L<C<< (?>pattern) >>>.
+
+=head2 Version 8 Regular Expressions
+X<regular expression, version 8> X<regex, version 8> X<regexp, version 8>
+
+In case you're not familiar with the "regular" Version 8 regex
+routines, here are the pattern-matching rules not described above.
+
+Any single character matches itself, unless it is a I<metacharacter>
+with a special meaning described here or above. You can cause
+characters that normally function as metacharacters to be interpreted
+literally by prefixing them with a "\" (e.g., "\." matches a ".", not any
+character; "\\" matches a "\"). This escape mechanism is also required
+for the character used as the pattern delimiter.
+
+A series of characters matches that series of characters in the target
+string, so the pattern C<blurfl> would match "blurfl" in the target
+string.
+
+You can specify a character class, by enclosing a list of characters
+in C<[]>, which will match any character from the list. If the
+first character after the "[" is "^", the class matches any character not
+in the list. Within a list, the "-" character specifies a
+range, so that C<a-z> represents all characters between "a" and "z",
+inclusive. If you want either "-" or "]" itself to be a member of a
+class, put it at the start of the list (possibly after a "^"), or
+escape it with a backslash. "-" is also taken literally when it is
+at the end of the list, just before the closing "]". (The
+following all specify the same class of three characters: C<[-az]>,
+C<[az-]>, and C<[a\-z]>. All are different from C<[a-z]>, which
+specifies a class containing twenty-six characters, even on EBCDIC-based
+character sets.) Also, if you try to use the character
+classes C<\w>, C<\W>, C<\s>, C<\S>, C<\d>, or C<\D> as endpoints of
+a range, the "-" is understood literally.
+
+Note also that the whole range idea is rather unportable between
+character sets--and even within character sets they may cause results
+you probably didn't expect. A sound principle is to use only ranges
+that begin from and end at either alphabetics of equal case ([a-e],
+[A-E]), or digits ([0-9]). Anything else is unsafe. If in doubt,
+spell out the character sets in full.
+
+Characters may be specified using a metacharacter syntax much like that
+used in C: "\n" matches a newline, "\t" a tab, "\r" a carriage return,
+"\f" a form feed, etc. More generally, \I<nnn>, where I<nnn> is a string
+of octal digits, matches the character whose coded character set value
+is I<nnn>. Similarly, \xI<nn>, where I<nn> are hexadecimal digits,
+matches the character whose numeric value is I<nn>. The expression \cI<x>
+matches the character control-I<x>. Finally, the "." metacharacter
+matches any character except "\n" (unless you use C</s>).
+
+You can specify a series of alternatives for a pattern using "|" to
+separate them, so that C<fee|fie|foe> will match any of "fee", "fie",
+or "foe" in the target string (as would C<f(e|i|o)e>). The
+first alternative includes everything from the last pattern delimiter
+("(", "[", or the beginning of the pattern) up to the first "|", and
+the last alternative contains everything from the last "|" to the next
+pattern delimiter. That's why it's common practice to include
+alternatives in parentheses: to minimize confusion about where they
+start and end.
+
+Alternatives are tried from left to right, so the first
+alternative found for which the entire expression matches, is the one that
+is chosen. This means that alternatives are not necessarily greedy. For
+example: when matching C<foo|foot> against "barefoot", only the "foo"
+part will match, as that is the first alternative tried, and it successfully
+matches the target string. (This might not seem important, but it is
+important when you are capturing matched text using parentheses.)
+
+Also remember that "|" is interpreted as a literal within square brackets,
+so if you write C<[fee|fie|foe]> you're really only matching C<[feio|]>.
+
+Within a pattern, you may designate subpatterns for later reference
+by enclosing them in parentheses, and you may refer back to the
+I<n>th subpattern later in the pattern using the metacharacter
+\I<n>. Subpatterns are numbered based on the left to right order
+of their opening parenthesis. A backreference matches whatever
+actually matched the subpattern in the string being examined, not
+the rules for that subpattern. Therefore, C<(0|0x)\d*\s\1\d*> will
+match "0x1234 0x4321", but not "0x1234 01234", because subpattern
+1 matched "0x", even though the rule C<0|0x> could potentially match
+the leading 0 in the second number.
+
+=head2 Warning on \1 Instead of $1
+
+Some people get too used to writing things like:
+
+ $pattern =~ s/(\W)/\\\1/g;
+
+This is grandfathered (for \1 to \9) for the RHS of a substitute to avoid
+shocking the
+B<sed> addicts, but it's a dirty habit to get into. That's because in
+PerlThink, the righthand side of an C<s///> is a double-quoted string. C<\1> in
+the usual double-quoted string means a control-A. The customary Unix
+meaning of C<\1> is kludged in for C<s///>. However, if you get into the habit
+of doing that, you get yourself into trouble if you then add an C</e>
+modifier.
+
+ s/(\d+)/ \1 + 1 /eg; # causes warning under -w
+
+Or if you try to do
+
+ s/(\d+)/\1000/;
+
+You can't disambiguate that by saying C<\{1}000>, whereas you can fix it with
+C<${1}000>. The operation of interpolation should not be confused
+with the operation of matching a backreference. Certainly they mean two
+different things on the I<left> side of the C<s///>.
+
+=head2 Repeated Patterns Matching a Zero-length Substring
+
+B<WARNING>: Difficult material (and prose) ahead. This section needs a rewrite.
+
+Regular expressions provide a terse and powerful programming language. As
+with most other power tools, power comes together with the ability
+to wreak havoc.
+
+A common abuse of this power stems from the ability to make infinite
+loops using regular expressions, with something as innocuous as:
+
+ 'foo' =~ m{ ( o? )* }x;
+
+The C<o?> matches at the beginning of C<'foo'>, and since the position
+in the string is not moved by the match, C<o?> would match again and again
+because of the C<*> quantifier. Another common way to create a similar cycle
+is with the looping modifier C<//g>:
+
+ @matches = ( 'foo' =~ m{ o? }xg );
+
+or
+
+ print "match: <$&>\n" while 'foo' =~ m{ o? }xg;
+
+or the loop implied by split().
+
+However, long experience has shown that many programming tasks may
+be significantly simplified by using repeated subexpressions that
+may match zero-length substrings. Here's a simple example being:
+
+ @chars = split //, $string; # // is not magic in split
+ ($whitewashed = $string) =~ s/()/ /g; # parens avoid magic s// /
+
+Thus Perl allows such constructs, by I<forcefully breaking
+the infinite loop>. The rules for this are different for lower-level
+loops given by the greedy quantifiers C<*+{}>, and for higher-level
+ones like the C</g> modifier or split() operator.
+
+The lower-level loops are I<interrupted> (that is, the loop is
+broken) when Perl detects that a repeated expression matched a
+zero-length substring. Thus
+
+ m{ (?: NON_ZERO_LENGTH | ZERO_LENGTH )* }x;
+
+is made equivalent to
+
+ m{ (?: NON_ZERO_LENGTH )*
+ |
+ (?: ZERO_LENGTH )?
+ }x;
+
+The higher level-loops preserve an additional state between iterations:
+whether the last match was zero-length. To break the loop, the following
+match after a zero-length match is prohibited to have a length of zero.
+This prohibition interacts with backtracking (see L<"Backtracking">),
+and so the I<second best> match is chosen if the I<best> match is of
+zero length.
+
+For example:
+
+ $_ = 'bar';
+ s/\w??/<$&>/g;
+
+results in C<< <><b><><a><><r><> >>. At each position of the string the best
+match given by non-greedy C<??> is the zero-length match, and the I<second
+best> match is what is matched by C<\w>. Thus zero-length matches
+alternate with one-character-long matches.
+
+Similarly, for repeated C<m/()/g> the second-best match is the match at the
+position one notch further in the string.
+
+The additional state of being I<matched with zero-length> is associated with
+the matched string, and is reset by each assignment to pos().
+Zero-length matches at the end of the previous match are ignored
+during C<split>.
+
+=head2 Combining RE Pieces
+
+Each of the elementary pieces of regular expressions which were described
+before (such as C<ab> or C<\Z>) could match at most one substring
+at the given position of the input string. However, in a typical regular
+expression these elementary pieces are combined into more complicated
+patterns using combining operators C<ST>, C<S|T>, C<S*> etc
+(in these examples C<S> and C<T> are regular subexpressions).
+
+Such combinations can include alternatives, leading to a problem of choice:
+if we match a regular expression C<a|ab> against C<"abc">, will it match
+substring C<"a"> or C<"ab">? One way to describe which substring is
+actually matched is the concept of backtracking (see L<"Backtracking">).
+However, this description is too low-level and makes you think
+in terms of a particular implementation.
+
+Another description starts with notions of "better"/"worse". All the
+substrings which may be matched by the given regular expression can be
+sorted from the "best" match to the "worst" match, and it is the "best"
+match which is chosen. This substitutes the question of "what is chosen?"
+by the question of "which matches are better, and which are worse?".
+
+Again, for elementary pieces there is no such question, since at most
+one match at a given position is possible. This section describes the
+notion of better/worse for combining operators. In the description
+below C<S> and C<T> are regular subexpressions.
+
+=over 4
+
+=item C<ST>
+
+Consider two possible matches, C<AB> and C<A'B'>, C<A> and C<A'> are
+substrings which can be matched by C<S>, C<B> and C<B'> are substrings
+which can be matched by C<T>.
+
+If C<A> is better match for C<S> than C<A'>, C<AB> is a better
+match than C<A'B'>.
+
+If C<A> and C<A'> coincide: C<AB> is a better match than C<AB'> if
+C<B> is better match for C<T> than C<B'>.
+
+=item C<S|T>
+
+When C<S> can match, it is a better match than when only C<T> can match.
+
+Ordering of two matches for C<S> is the same as for C<S>. Similar for
+two matches for C<T>.
+
+=item C<S{REPEAT_COUNT}>
+
+Matches as C<SSS...S> (repeated as many times as necessary).
+
+=item C<S{min,max}>
+
+Matches as C<S{max}|S{max-1}|...|S{min+1}|S{min}>.
+
+=item C<S{min,max}?>
+
+Matches as C<S{min}|S{min+1}|...|S{max-1}|S{max}>.
+
+=item C<S?>, C<S*>, C<S+>
+
+Same as C<S{0,1}>, C<S{0,BIG_NUMBER}>, C<S{1,BIG_NUMBER}> respectively.
+
+=item C<S??>, C<S*?>, C<S+?>
+
+Same as C<S{0,1}?>, C<S{0,BIG_NUMBER}?>, C<S{1,BIG_NUMBER}?> respectively.
+
+=item C<< (?>S) >>
+
+Matches the best match for C<S> and only that.
+
+=item C<(?=S)>, C<(?<=S)>
+
+Only the best match for C<S> is considered. (This is important only if
+C<S> has capturing parentheses, and backreferences are used somewhere
+else in the whole regular expression.)
+
+=item C<(?!S)>, C<(?<!S)>
+
+For this grouping operator there is no need to describe the ordering, since
+only whether or not C<S> can match is important.
+
+=item C<(??{ EXPR })>, C<(?PARNO)>
+
+The ordering is the same as for the regular expression which is
+the result of EXPR, or the pattern contained by capture buffer PARNO.
+
+=item C<(?(condition)yes-pattern|no-pattern)>
+
+Recall that which of C<yes-pattern> or C<no-pattern> actually matches is
+already determined. The ordering of the matches is the same as for the
+chosen subexpression.
+
+=back
+
+The above recipes describe the ordering of matches I<at a given position>.
+One more rule is needed to understand how a match is determined for the
+whole regular expression: a match at an earlier position is always better
+than a match at a later position.
+
+=head2 Creating Custom RE Engines
+
+Overloaded constants (see L<overload>) provide a simple way to extend
+the functionality of the RE engine.
+
+Suppose that we want to enable a new RE escape-sequence C<\Y|> which
+matches at a boundary between whitespace characters and non-whitespace
+characters. Note that C<(?=\S)(?<!\S)|(?!\S)(?<=\S)> matches exactly
+at these positions, so we want to have each C<\Y|> in the place of the
+more complicated version. We can create a module C<customre> to do
+this:
+
+ package customre;
+ use overload;
+
+ sub import {
+ shift;
+ die "No argument to customre::import allowed" if @_;
+ overload::constant 'qr' => \&convert;
+ }
+
+ sub invalid { die "/$_[0]/: invalid escape '\\$_[1]'"}
+
+ # We must also take care of not escaping the legitimate \\Y|
+ # sequence, hence the presence of '\\' in the conversion rules.
+ my %rules = ( '\\' => '\\\\',
+ 'Y|' => qr/(?=\S)(?<!\S)|(?!\S)(?<=\S)/ );
+ sub convert {
+ my $re = shift;
+ $re =~ s{
+ \\ ( \\ | Y . )
+ }
+ { $rules{$1} or invalid($re,$1) }sgex;
+ return $re;
+ }
+
+Now C<use customre> enables the new escape in constant regular
+expressions, i.e., those without any runtime variable interpolations.
+As documented in L<overload>, this conversion will work only over
+literal parts of regular expressions. For C<\Y|$re\Y|> the variable
+part of this regular expression needs to be converted explicitly
+(but only if the special meaning of C<\Y|> should be enabled inside $re):
+
+ use customre;
+ $re = <>;
+ chomp $re;
+ $re = customre::convert $re;
+ /\Y|$re\Y|/;
+
+=head1 PCRE/Python Support
+
+As of Perl 5.10.0, Perl supports several Python/PCRE specific extensions
+to the regex syntax. While Perl programmers are encouraged to use the
+Perl specific syntax, the following are also accepted:
+
+=over 4
+
+=item C<< (?PE<lt>NAMEE<gt>pattern) >>
+
+Define a named capture buffer. Equivalent to C<< (?<NAME>pattern) >>.
+
+=item C<< (?P=NAME) >>
+
+Backreference to a named capture buffer. Equivalent to C<< \g{NAME} >>.
+
+=item C<< (?P>NAME) >>
+
+Subroutine call to a named capture buffer. Equivalent to C<< (?&NAME) >>.
+
+=back
+
+=head1 BUGS
+
+There are numerous problems with case insensitive matching of characters
+outside the ASCII range, especially with those whose folds are multiple
+characters, such as ligatures like C<LATIN SMALL LIGATURE FF>.
+
+In a bracketed character class with case insensitive matching, ranges only work
+for ASCII characters. For example,
+C<m/[\N{CYRILLIC CAPITAL LETTER A}-\N{CYRILLIC CAPITAL LETTER YA}]/i>
+doesn't match all the Russian upper and lower case letters.
+
+Many regular expression constructs don't work on EBCDIC platforms.
+
+This document varies from difficult to understand to completely
+and utterly opaque. The wandering prose riddled with jargon is
+hard to fathom in several places.
+
+This document needs a rewrite that separates the tutorial content
+from the reference content.
+
+=head1 SEE ALSO
+
+L<perlrequick>.
+
+L<perlretut>.
+
+L<perlop/"Regexp Quote-Like Operators">.
+
+L<perlop/"Gory details of parsing quoted constructs">.
+
+L<perlfaq6>.
+
+L<perlfunc/pos>.
+
+L<perllocale>.
+
+L<perlebcdic>.
+
+I<Mastering Regular Expressions> by Jeffrey Friedl, published
+by O'Reilly and Associates.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlreapi.pod b/Master/tlpkg/tlperl/lib/pods/perlreapi.pod
new file mode 100644
index 00000000000..d1d947b8a74
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlreapi.pod
@@ -0,0 +1,699 @@
+=head1 NAME
+
+perlreapi - perl regular expression plugin interface
+
+=head1 DESCRIPTION
+
+As of Perl 5.9.5 there is a new interface for plugging and using other
+regular expression engines than the default one.
+
+Each engine is supposed to provide access to a constant structure of the
+following format:
+
+ typedef struct regexp_engine {
+ REGEXP* (*comp) (pTHX_ const SV * const pattern, const U32 flags);
+ I32 (*exec) (pTHX_ REGEXP * const rx, char* stringarg, char* strend,
+ char* strbeg, I32 minend, SV* screamer,
+ void* data, U32 flags);
+ char* (*intuit) (pTHX_ REGEXP * const rx, SV *sv, char *strpos,
+ char *strend, U32 flags,
+ struct re_scream_pos_data_s *data);
+ SV* (*checkstr) (pTHX_ REGEXP * const rx);
+ void (*free) (pTHX_ REGEXP * const rx);
+ void (*numbered_buff_FETCH) (pTHX_ REGEXP * const rx, const I32 paren,
+ SV * const sv);
+ void (*numbered_buff_STORE) (pTHX_ REGEXP * const rx, const I32 paren,
+ SV const * const value);
+ I32 (*numbered_buff_LENGTH) (pTHX_ REGEXP * const rx, const SV * const sv,
+ const I32 paren);
+ SV* (*named_buff) (pTHX_ REGEXP * const rx, SV * const key,
+ SV * const value, U32 flags);
+ SV* (*named_buff_iter) (pTHX_ REGEXP * const rx, const SV * const lastkey,
+ const U32 flags);
+ SV* (*qr_package)(pTHX_ REGEXP * const rx);
+ #ifdef USE_ITHREADS
+ void* (*dupe) (pTHX_ REGEXP * const rx, CLONE_PARAMS *param);
+ #endif
+
+When a regexp is compiled, its C<engine> field is then set to point at
+the appropriate structure, so that when it needs to be used Perl can find
+the right routines to do so.
+
+In order to install a new regexp handler, C<$^H{regcomp}> is set
+to an integer which (when casted appropriately) resolves to one of these
+structures. When compiling, the C<comp> method is executed, and the
+resulting regexp structure's engine field is expected to point back at
+the same structure.
+
+The pTHX_ symbol in the definition is a macro used by perl under threading
+to provide an extra argument to the routine holding a pointer back to
+the interpreter that is executing the regexp. So under threading all
+routines get an extra argument.
+
+=head1 Callbacks
+
+=head2 comp
+
+ REGEXP* comp(pTHX_ const SV * const pattern, const U32 flags);
+
+Compile the pattern stored in C<pattern> using the given C<flags> and
+return a pointer to a prepared C<REGEXP> structure that can perform
+the match. See L</The REGEXP structure> below for an explanation of
+the individual fields in the REGEXP struct.
+
+The C<pattern> parameter is the scalar that was used as the
+pattern. previous versions of perl would pass two C<char*> indicating
+the start and end of the stringified pattern, the following snippet can
+be used to get the old parameters:
+
+ STRLEN plen;
+ char* exp = SvPV(pattern, plen);
+ char* xend = exp + plen;
+
+Since any scalar can be passed as a pattern it's possible to implement
+an engine that does something with an array (C<< "ook" =~ [ qw/ eek
+hlagh / ] >>) or with the non-stringified form of a compiled regular
+expression (C<< "ook" =~ qr/eek/ >>). perl's own engine will always
+stringify everything using the snippet above but that doesn't mean
+other engines have to.
+
+The C<flags> parameter is a bitfield which indicates which of the
+C<msixp> flags the regex was compiled with. It also contains
+additional info such as whether C<use locale> is in effect.
+
+The C<eogc> flags are stripped out before being passed to the comp
+routine. The regex engine does not need to know whether any of these
+are set as those flags should only affect what perl does with the
+pattern and its match variables, not how it gets compiled and
+executed.
+
+By the time the comp callback is called, some of these flags have
+already had effect (noted below where applicable). However most of
+their effect occurs after the comp callback has run in routines that
+read the C<< rx->extflags >> field which it populates.
+
+In general the flags should be preserved in C<< rx->extflags >> after
+compilation, although the regex engine might want to add or delete
+some of them to invoke or disable some special behavior in perl. The
+flags along with any special behavior they cause are documented below:
+
+The pattern modifiers:
+
+=over 4
+
+=item C</m> - RXf_PMf_MULTILINE
+
+If this is in C<< rx->extflags >> it will be passed to
+C<Perl_fbm_instr> by C<pp_split> which will treat the subject string
+as a multi-line string.
+
+=item C</s> - RXf_PMf_SINGLELINE
+
+=item C</i> - RXf_PMf_FOLD
+
+=item C</x> - RXf_PMf_EXTENDED
+
+If present on a regex C<#> comments will be handled differently by the
+tokenizer in some cases.
+
+TODO: Document those cases.
+
+=item C</p> - RXf_PMf_KEEPCOPY
+
+=back
+
+Additional flags:
+
+=over 4
+
+=item RXf_PMf_LOCALE
+
+Set if C<use locale> is in effect. If present in C<< rx->extflags >>
+C<split> will use the locale dependent definition of whitespace under
+when RXf_SKIPWHITE or RXf_WHITE are in effect. Under ASCII whitespace
+is defined as per L<isSPACE|perlapi/ISSPACE>, and by the internal
+macros C<is_utf8_space> under UTF-8 and C<isSPACE_LC> under C<use
+locale>.
+
+=item RXf_UTF8
+
+Set if the pattern is L<SvUTF8()|perlapi/SvUTF8>, set by Perl_pmruntime.
+
+A regex engine may want to set or disable this flag during
+compilation. The perl engine for instance may upgrade non-UTF-8
+strings to UTF-8 if the pattern includes constructs such as C<\x{...}>
+that can only match Unicode values.
+
+=item RXf_SPLIT
+
+If C<split> is invoked as C<split ' '> or with no arguments (which
+really means C<split(' ', $_)>, see L<split|perlfunc/split>), perl will
+set this flag. The regex engine can then check for it and set the
+SKIPWHITE and WHITE extflags. To do this the perl engine does:
+
+ if (flags & RXf_SPLIT && r->prelen == 1 && r->precomp[0] == ' ')
+ r->extflags |= (RXf_SKIPWHITE|RXf_WHITE);
+
+=back
+
+These flags can be set during compilation to enable optimizations in
+the C<split> operator.
+
+=over 4
+
+=item RXf_SKIPWHITE
+
+If the flag is present in C<< rx->extflags >> C<split> will delete
+whitespace from the start of the subject string before it's operated
+on. What is considered whitespace depends on whether the subject is a
+UTF-8 string and whether the C<RXf_PMf_LOCALE> flag is set.
+
+If RXf_WHITE is set in addition to this flag C<split> will behave like
+C<split " "> under the perl engine.
+
+=item RXf_START_ONLY
+
+Tells the split operator to split the target string on newlines
+(C<\n>) without invoking the regex engine.
+
+Perl's engine sets this if the pattern is C</^/> (C<plen == 1 && *exp
+== '^'>), even under C</^/s>, see L<split|perlfunc>. Of course a
+different regex engine might want to use the same optimizations
+with a different syntax.
+
+=item RXf_WHITE
+
+Tells the split operator to split the target string on whitespace
+without invoking the regex engine. The definition of whitespace varies
+depending on whether the target string is a UTF-8 string and on
+whether RXf_PMf_LOCALE is set.
+
+Perl's engine sets this flag if the pattern is C<\s+>.
+
+=item RXf_NULL
+
+Tells the split operator to split the target string on
+characters. The definition of character varies depending on whether
+the target string is a UTF-8 string.
+
+Perl's engine sets this flag on empty patterns, this optimization
+makes C<split //> much faster than it would otherwise be. It's even
+faster than C<unpack>.
+
+=back
+
+=head2 exec
+
+ I32 exec(pTHX_ REGEXP * const rx,
+ char *stringarg, char* strend, char* strbeg,
+ I32 minend, SV* screamer,
+ void* data, U32 flags);
+
+Execute a regexp.
+
+=head2 intuit
+
+ char* intuit(pTHX_ REGEXP * const rx,
+ SV *sv, char *strpos, char *strend,
+ const U32 flags, struct re_scream_pos_data_s *data);
+
+Find the start position where a regex match should be attempted,
+or possibly whether the regex engine should not be run because the
+pattern can't match. This is called as appropriate by the core
+depending on the values of the extflags member of the regexp
+structure.
+
+=head2 checkstr
+
+ SV* checkstr(pTHX_ REGEXP * const rx);
+
+Return a SV containing a string that must appear in the pattern. Used
+by C<split> for optimising matches.
+
+=head2 free
+
+ void free(pTHX_ REGEXP * const rx);
+
+Called by perl when it is freeing a regexp pattern so that the engine
+can release any resources pointed to by the C<pprivate> member of the
+regexp structure. This is only responsible for freeing private data;
+perl will handle releasing anything else contained in the regexp structure.
+
+=head2 Numbered capture callbacks
+
+Called to get/set the value of C<$`>, C<$'>, C<$&> and their named
+equivalents, ${^PREMATCH}, ${^POSTMATCH} and $^{MATCH}, as well as the
+numbered capture buffers (C<$1>, C<$2>, ...).
+
+The C<paren> parameter will be C<-2> for C<$`>, C<-1> for C<$'>, C<0>
+for C<$&>, C<1> for C<$1> and so forth.
+
+The names have been chosen by analogy with L<Tie::Scalar> methods
+names with an additional B<LENGTH> callback for efficiency. However
+named capture variables are currently not tied internally but
+implemented via magic.
+
+=head3 numbered_buff_FETCH
+
+ void numbered_buff_FETCH(pTHX_ REGEXP * const rx, const I32 paren,
+ SV * const sv);
+
+Fetch a specified numbered capture. C<sv> should be set to the scalar
+to return, the scalar is passed as an argument rather than being
+returned from the function because when it's called perl already has a
+scalar to store the value, creating another one would be
+redundant. The scalar can be set with C<sv_setsv>, C<sv_setpvn> and
+friends, see L<perlapi>.
+
+This callback is where perl untaints its own capture variables under
+taint mode (see L<perlsec>). See the C<Perl_reg_numbered_buff_fetch>
+function in F<regcomp.c> for how to untaint capture variables if
+that's something you'd like your engine to do as well.
+
+=head3 numbered_buff_STORE
+
+ void (*numbered_buff_STORE) (pTHX_ REGEXP * const rx, const I32 paren,
+ SV const * const value);
+
+Set the value of a numbered capture variable. C<value> is the scalar
+that is to be used as the new value. It's up to the engine to make
+sure this is used as the new value (or reject it).
+
+Example:
+
+ if ("ook" =~ /(o*)/) {
+ # `paren' will be `1' and `value' will be `ee'
+ $1 =~ tr/o/e/;
+ }
+
+Perl's own engine will croak on any attempt to modify the capture
+variables, to do this in another engine use the following callback
+(copied from C<Perl_reg_numbered_buff_store>):
+
+ void
+ Example_reg_numbered_buff_store(pTHX_ REGEXP * const rx, const I32 paren,
+ SV const * const value)
+ {
+ PERL_UNUSED_ARG(rx);
+ PERL_UNUSED_ARG(paren);
+ PERL_UNUSED_ARG(value);
+
+ if (!PL_localizing)
+ Perl_croak(aTHX_ PL_no_modify);
+ }
+
+Actually perl will not I<always> croak in a statement that looks
+like it would modify a numbered capture variable. This is because the
+STORE callback will not be called if perl can determine that it
+doesn't have to modify the value. This is exactly how tied variables
+behave in the same situation:
+
+ package CaptureVar;
+ use base 'Tie::Scalar';
+
+ sub TIESCALAR { bless [] }
+ sub FETCH { undef }
+ sub STORE { die "This doesn't get called" }
+
+ package main;
+
+ tie my $sv => "CatptureVar";
+ $sv =~ y/a/b/;
+
+Because C<$sv> is C<undef> when the C<y///> operator is applied to it
+the transliteration won't actually execute and the program won't
+C<die>. This is different to how 5.8 and earlier versions behaved
+since the capture variables were READONLY variables then, now they'll
+just die when assigned to in the default engine.
+
+=head3 numbered_buff_LENGTH
+
+ I32 numbered_buff_LENGTH (pTHX_ REGEXP * const rx, const SV * const sv,
+ const I32 paren);
+
+Get the C<length> of a capture variable. There's a special callback
+for this so that perl doesn't have to do a FETCH and run C<length> on
+the result, since the length is (in perl's case) known from an offset
+stored in C<< rx->offs >> this is much more efficient:
+
+ I32 s1 = rx->offs[paren].start;
+ I32 s2 = rx->offs[paren].end;
+ I32 len = t1 - s1;
+
+This is a little bit more complex in the case of UTF-8, see what
+C<Perl_reg_numbered_buff_length> does with
+L<is_utf8_string_loclen|perlapi/is_utf8_string_loclen>.
+
+=head2 Named capture callbacks
+
+Called to get/set the value of C<%+> and C<%-> as well as by some
+utility functions in L<re>.
+
+There are two callbacks, C<named_buff> is called in all the cases the
+FETCH, STORE, DELETE, CLEAR, EXISTS and SCALAR L<Tie::Hash> callbacks
+would be on changes to C<%+> and C<%-> and C<named_buff_iter> in the
+same cases as FIRSTKEY and NEXTKEY.
+
+The C<flags> parameter can be used to determine which of these
+operations the callbacks should respond to, the following flags are
+currently defined:
+
+Which L<Tie::Hash> operation is being performed from the Perl level on
+C<%+> or C<%+>, if any:
+
+ RXapif_FETCH
+ RXapif_STORE
+ RXapif_DELETE
+ RXapif_CLEAR
+ RXapif_EXISTS
+ RXapif_SCALAR
+ RXapif_FIRSTKEY
+ RXapif_NEXTKEY
+
+Whether C<%+> or C<%-> is being operated on, if any.
+
+ RXapif_ONE /* %+ */
+ RXapif_ALL /* %- */
+
+Whether this is being called as C<re::regname>, C<re::regnames> or
+C<re::regnames_count>, if any. The first two will be combined with
+C<RXapif_ONE> or C<RXapif_ALL>.
+
+ RXapif_REGNAME
+ RXapif_REGNAMES
+ RXapif_REGNAMES_COUNT
+
+Internally C<%+> and C<%-> are implemented with a real tied interface
+via L<Tie::Hash::NamedCapture>. The methods in that package will call
+back into these functions. However the usage of
+L<Tie::Hash::NamedCapture> for this purpose might change in future
+releases. For instance this might be implemented by magic instead
+(would need an extension to mgvtbl).
+
+=head3 named_buff
+
+ SV* (*named_buff) (pTHX_ REGEXP * const rx, SV * const key,
+ SV * const value, U32 flags);
+
+=head3 named_buff_iter
+
+ SV* (*named_buff_iter) (pTHX_ REGEXP * const rx, const SV * const lastkey,
+ const U32 flags);
+
+=head2 qr_package
+
+ SV* qr_package(pTHX_ REGEXP * const rx);
+
+The package the qr// magic object is blessed into (as seen by C<ref
+qr//>). It is recommended that engines change this to their package
+name for identification regardless of whether they implement methods
+on the object.
+
+The package this method returns should also have the internal
+C<Regexp> package in its C<@ISA>. C<< qr//->isa("Regexp") >> should always
+be true regardless of what engine is being used.
+
+Example implementation might be:
+
+ SV*
+ Example_qr_package(pTHX_ REGEXP * const rx)
+ {
+ PERL_UNUSED_ARG(rx);
+ return newSVpvs("re::engine::Example");
+ }
+
+Any method calls on an object created with C<qr//> will be dispatched to the
+package as a normal object.
+
+ use re::engine::Example;
+ my $re = qr//;
+ $re->meth; # dispatched to re::engine::Example::meth()
+
+To retrieve the C<REGEXP> object from the scalar in an XS function use
+the C<SvRX> macro, see L<"REGEXP Functions" in perlapi|perlapi/REGEXP
+Functions>.
+
+ void meth(SV * rv)
+ PPCODE:
+ REGEXP * re = SvRX(sv);
+
+=head2 dupe
+
+ void* dupe(pTHX_ REGEXP * const rx, CLONE_PARAMS *param);
+
+On threaded builds a regexp may need to be duplicated so that the pattern
+can be used by multiple threads. This routine is expected to handle the
+duplication of any private data pointed to by the C<pprivate> member of
+the regexp structure. It will be called with the preconstructed new
+regexp structure as an argument, the C<pprivate> member will point at
+the B<old> private structure, and it is this routine's responsibility to
+construct a copy and return a pointer to it (which perl will then use to
+overwrite the field as passed to this routine.)
+
+This allows the engine to dupe its private data but also if necessary
+modify the final structure if it really must.
+
+On unthreaded builds this field doesn't exist.
+
+=head1 The REGEXP structure
+
+The REGEXP struct is defined in F<regexp.h>. All regex engines must be able to
+correctly build such a structure in their L</comp> routine.
+
+The REGEXP structure contains all the data that perl needs to be aware of
+to properly work with the regular expression. It includes data about
+optimisations that perl can use to determine if the regex engine should
+really be used, and various other control info that is needed to properly
+execute patterns in various contexts such as is the pattern anchored in
+some way, or what flags were used during the compile, or whether the
+program contains special constructs that perl needs to be aware of.
+
+In addition it contains two fields that are intended for the private
+use of the regex engine that compiled the pattern. These are the
+C<intflags> and C<pprivate> members. C<pprivate> is a void pointer to
+an arbitrary structure whose use and management is the responsibility
+of the compiling engine. perl will never modify either of these
+values.
+
+ typedef struct regexp {
+ /* what engine created this regexp? */
+ const struct regexp_engine* engine;
+
+ /* what re is this a lightweight copy of? */
+ struct regexp* mother_re;
+
+ /* Information about the match that the perl core uses to manage things */
+ U32 extflags; /* Flags used both externally and internally */
+ I32 minlen; /* mininum possible length of string to match */
+ I32 minlenret; /* mininum possible length of $& */
+ U32 gofs; /* chars left of pos that we search from */
+
+ /* substring data about strings that must appear
+ in the final match, used for optimisations */
+ struct reg_substr_data *substrs;
+
+ U32 nparens; /* number of capture buffers */
+
+ /* private engine specific data */
+ U32 intflags; /* Engine Specific Internal flags */
+ void *pprivate; /* Data private to the regex engine which
+ created this object. */
+
+ /* Data about the last/current match. These are modified during matching*/
+ U32 lastparen; /* last open paren matched */
+ U32 lastcloseparen; /* last close paren matched */
+ regexp_paren_pair *swap; /* Swap copy of *offs */
+ regexp_paren_pair *offs; /* Array of offsets for (@-) and (@+) */
+
+ char *subbeg; /* saved or original string so \digit works forever. */
+ SV_SAVED_COPY /* If non-NULL, SV which is COW from original */
+ I32 sublen; /* Length of string pointed by subbeg */
+
+ /* Information about the match that isn't often used */
+ I32 prelen; /* length of precomp */
+ const char *precomp; /* pre-compilation regular expression */
+
+ char *wrapped; /* wrapped version of the pattern */
+ I32 wraplen; /* length of wrapped */
+
+ I32 seen_evals; /* number of eval groups in the pattern - for security checks */
+ HV *paren_names; /* Optional hash of paren names */
+
+ /* Refcount of this regexp */
+ I32 refcnt; /* Refcount of this regexp */
+ } regexp;
+
+The fields are discussed in more detail below:
+
+=head2 C<engine>
+
+This field points at a regexp_engine structure which contains pointers
+to the subroutines that are to be used for performing a match. It
+is the compiling routine's responsibility to populate this field before
+returning the regexp object.
+
+Internally this is set to C<NULL> unless a custom engine is specified in
+C<$^H{regcomp}>, perl's own set of callbacks can be accessed in the struct
+pointed to by C<RE_ENGINE_PTR>.
+
+=head2 C<mother_re>
+
+TODO, see L<http://www.mail-archive.com/perl5-changes@perl.org/msg17328.html>
+
+=head2 C<extflags>
+
+This will be used by perl to see what flags the regexp was compiled
+with, this will normally be set to the value of the flags parameter by
+the L<comp|/comp> callback. See the L<comp|/comp> documentation for
+valid flags.
+
+=head2 C<minlen> C<minlenret>
+
+The minimum string length required for the pattern to match. This is used to
+prune the search space by not bothering to match any closer to the end of a
+string than would allow a match. For instance there is no point in even
+starting the regex engine if the minlen is 10 but the string is only 5
+characters long. There is no way that the pattern can match.
+
+C<minlenret> is the minimum length of the string that would be found
+in $& after a match.
+
+The difference between C<minlen> and C<minlenret> can be seen in the
+following pattern:
+
+ /ns(?=\d)/
+
+where the C<minlen> would be 3 but C<minlenret> would only be 2 as the \d is
+required to match but is not actually included in the matched content. This
+distinction is particularly important as the substitution logic uses the
+C<minlenret> to tell whether it can do in-place substitution which can result in
+considerable speedup.
+
+=head2 C<gofs>
+
+Left offset from pos() to start match at.
+
+=head2 C<substrs>
+
+Substring data about strings that must appear in the final match. This
+is currently only used internally by perl's engine for but might be
+used in the future for all engines for optimisations.
+
+=head2 C<nparens>, C<lasparen>, and C<lastcloseparen>
+
+These fields are used to keep track of how many paren groups could be matched
+in the pattern, which was the last open paren to be entered, and which was
+the last close paren to be entered.
+
+=head2 C<intflags>
+
+The engine's private copy of the flags the pattern was compiled with. Usually
+this is the same as C<extflags> unless the engine chose to modify one of them.
+
+=head2 C<pprivate>
+
+A void* pointing to an engine-defined data structure. The perl engine uses the
+C<regexp_internal> structure (see L<perlreguts/Base Structures>) but a custom
+engine should use something else.
+
+=head2 C<swap>
+
+Unused. Left in for compatibility with perl 5.10.0.
+
+=head2 C<offs>
+
+A C<regexp_paren_pair> structure which defines offsets into the string being
+matched which correspond to the C<$&> and C<$1>, C<$2> etc. captures, the
+C<regexp_paren_pair> struct is defined as follows:
+
+ typedef struct regexp_paren_pair {
+ I32 start;
+ I32 end;
+ } regexp_paren_pair;
+
+If C<< ->offs[num].start >> or C<< ->offs[num].end >> is C<-1> then that
+capture buffer did not match. C<< ->offs[0].start/end >> represents C<$&> (or
+C<${^MATCH> under C<//p>) and C<< ->offs[paren].end >> matches C<$$paren> where
+C<$paren >= 1>.
+
+=head2 C<precomp> C<prelen>
+
+Used for optimisations. C<precomp> holds a copy of the pattern that
+was compiled and C<prelen> its length. When a new pattern is to be
+compiled (such as inside a loop) the internal C<regcomp> operator
+checks whether the last compiled C<REGEXP>'s C<precomp> and C<prelen>
+are equivalent to the new one, and if so uses the old pattern instead
+of compiling a new one.
+
+The relevant snippet from C<Perl_pp_regcomp>:
+
+ if (!re || !re->precomp || re->prelen != (I32)len ||
+ memNE(re->precomp, t, len))
+ /* Compile a new pattern */
+
+=head2 C<paren_names>
+
+This is a hash used internally to track named capture buffers and their
+offsets. The keys are the names of the buffers the values are dualvars,
+with the IV slot holding the number of buffers with the given name and the
+pv being an embedded array of I32. The values may also be contained
+independently in the data array in cases where named backreferences are
+used.
+
+=head2 C<substrs>
+
+Holds information on the longest string that must occur at a fixed
+offset from the start of the pattern, and the longest string that must
+occur at a floating offset from the start of the pattern. Used to do
+Fast-Boyer-Moore searches on the string to find out if its worth using
+the regex engine at all, and if so where in the string to search.
+
+=head2 C<subbeg> C<sublen> C<saved_copy>
+
+Used during execution phase for managing search and replace patterns.
+
+=head2 C<wrapped> C<wraplen>
+
+Stores the string C<qr//> stringifies to. The perl engine for example
+stores C<(?-xism:eek)> in the case of C<qr/eek/>.
+
+When using a custom engine that doesn't support the C<(?:)> construct
+for inline modifiers, it's probably best to have C<qr//> stringify to
+the supplied pattern, note that this will create undesired patterns in
+cases such as:
+
+ my $x = qr/a|b/; # "a|b"
+ my $y = qr/c/i; # "c"
+ my $z = qr/$x$y/; # "a|bc"
+
+There's no solution for this problem other than making the custom
+engine understand a construct like C<(?:)>.
+
+=head2 C<seen_evals>
+
+This stores the number of eval groups in the pattern. This is used for security
+purposes when embedding compiled regexes into larger patterns with C<qr//>.
+
+=head2 C<refcnt>
+
+The number of times the structure is referenced. When this falls to 0 the
+regexp is automatically freed by a call to pregfree. This should be set to 1 in
+each engine's L</comp> routine.
+
+=head1 HISTORY
+
+Originally part of L<perlreguts>.
+
+=head1 AUTHORS
+
+Originally written by Yves Orton, expanded by E<AElig>var ArnfjE<ouml>rE<eth>
+Bjarmason.
+
+=head1 LICENSE
+
+Copyright 2006 Yves Orton and 2007 E<AElig>var ArnfjE<ouml>rE<eth> Bjarmason.
+
+This program is free software; you can redistribute it and/or modify it under
+the same terms as Perl itself.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlrebackslash.pod b/Master/tlpkg/tlperl/lib/pods/perlrebackslash.pod
new file mode 100644
index 00000000000..489ba2b648f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlrebackslash.pod
@@ -0,0 +1,583 @@
+=head1 NAME
+
+perlrebackslash - Perl Regular Expression Backslash Sequences and Escapes
+
+=head1 DESCRIPTION
+
+The top level documentation about Perl regular expressions
+is found in L<perlre>.
+
+This document describes all backslash and escape sequences. After
+explaining the role of the backslash, it lists all the sequences that have
+a special meaning in Perl regular expressions (in alphabetical order),
+then describes each of them.
+
+Most sequences are described in detail in different documents; the primary
+purpose of this document is to have a quick reference guide describing all
+backslash and escape sequences.
+
+=head2 The backslash
+
+In a regular expression, the backslash can perform one of two tasks:
+it either takes away the special meaning of the character following it
+(for instance, C<\|> matches a vertical bar, it's not an alternation),
+or it is the start of a backslash or escape sequence.
+
+The rules determining what it is are quite simple: if the character
+following the backslash is an ASCII punctuation (non-word) character (that is,
+anything that is not a letter, digit or underscore), then the backslash just
+takes away the special meaning (if any) of the character following it.
+
+If the character following the backslash is an ASCII letter or an ASCII digit,
+then the sequence may be special; if so, it's listed below. A few letters have
+not been used yet, so escaping them with a backslash doesn't change them to be
+special. A future version of Perl may assign a special meaning to them, so if
+you have warnings turned on, Perl will issue a warning if you use such a
+sequence. [1].
+
+It is however guaranteed that backslash or escape sequences never have a
+punctuation character following the backslash, not now, and not in a future
+version of Perl 5. So it is safe to put a backslash in front of a non-word
+character.
+
+Note that the backslash itself is special; if you want to match a backslash,
+you have to escape the backslash with a backslash: C</\\/> matches a single
+backslash.
+
+=over 4
+
+=item [1]
+
+There is one exception. If you use an alphanumerical character as the
+delimiter of your pattern (which you probably shouldn't do for readability
+reasons), you will have to escape the delimiter if you want to match
+it. Perl won't warn then. See also L<perlop/Gory details of parsing
+quoted constructs>.
+
+=back
+
+
+=head2 All the sequences and escapes
+
+Those not usable within a bracketed character class (like C<[\da-z]>) are marked
+as C<Not in [].>
+
+ \000 Octal escape sequence.
+ \1 Absolute backreference. Not in [].
+ \a Alarm or bell.
+ \A Beginning of string. Not in [].
+ \b Word/non-word boundary. (Backspace in []).
+ \B Not a word/non-word boundary. Not in [].
+ \cX Control-X
+ \C Single octet, even under UTF-8. Not in [].
+ \d Character class for digits.
+ \D Character class for non-digits.
+ \e Escape character.
+ \E Turn off \Q, \L and \U processing. Not in [].
+ \f Form feed.
+ \g{}, \g1 Named, absolute or relative backreference. Not in [].
+ \G Pos assertion. Not in [].
+ \h Character class for horizontal whitespace.
+ \H Character class for non horizontal whitespace.
+ \k{}, \k<>, \k'' Named backreference. Not in [].
+ \K Keep the stuff left of \K. Not in [].
+ \l Lowercase next character. Not in [].
+ \L Lowercase till \E. Not in [].
+ \n (Logical) newline character.
+ \N Any character but newline. Experimental. Not in [].
+ \N{} Named or numbered (Unicode) character.
+ \p{}, \pP Character with the given Unicode property.
+ \P{}, \PP Character without the given Unicode property.
+ \Q Quotemeta till \E. Not in [].
+ \r Return character.
+ \R Generic new line. Not in [].
+ \s Character class for whitespace.
+ \S Character class for non whitespace.
+ \t Tab character.
+ \u Titlecase next character. Not in [].
+ \U Uppercase till \E. Not in [].
+ \v Character class for vertical whitespace.
+ \V Character class for non vertical whitespace.
+ \w Character class for word characters.
+ \W Character class for non-word characters.
+ \x{}, \x00 Hexadecimal escape sequence.
+ \X Unicode "extended grapheme cluster". Not in [].
+ \z End of string. Not in [].
+ \Z End of string. Not in [].
+
+=head2 Character Escapes
+
+=head3 Fixed characters
+
+A handful of characters have a dedicated I<character escape>. The following
+table shows them, along with their ASCII code points (in decimal and hex),
+their ASCII name, the control escape on ASCII platforms and a short
+description. (For EBCDIC platforms, see L<perlebcdic/OPERATOR DIFFERENCES>.)
+
+ Seq. Code Point ASCII Cntrl Description.
+ Dec Hex
+ \a 7 07 BEL \cG alarm or bell
+ \b 8 08 BS \cH backspace [1]
+ \e 27 1B ESC \c[ escape character
+ \f 12 0C FF \cL form feed
+ \n 10 0A LF \cJ line feed [2]
+ \r 13 0D CR \cM carriage return
+ \t 9 09 TAB \cI tab
+
+=over 4
+
+=item [1]
+
+C<\b> is the backspace character only inside a character class. Outside a
+character class, C<\b> is a word/non-word boundary.
+
+=item [2]
+
+C<\n> matches a logical newline. Perl will convert between C<\n> and your
+OS's native newline character when reading from or writing to text files.
+
+=back
+
+=head4 Example
+
+ $str =~ /\t/; # Matches if $str contains a (horizontal) tab.
+
+=head3 Control characters
+
+C<\c> is used to denote a control character; the character following C<\c>
+determines the value of the construct. For example the value of C<\cA> is
+C<chr(1)>, and the value of C<\cb> is C<chr(2)>, etc.
+The gory details are in L<perlop/"Regexp Quote-Like Operators">. A complete
+list of what C<chr(1)>, etc. means for ASCII and EBCDIC platforms is in
+L<perlebcdic/OPERATOR DIFFERENCES>.
+
+Note that C<\c\> alone at the end of a regular expression (or doubled-quoted
+string) is not valid. The backslash must be followed by another character.
+That is, C<\c\I<X>> means C<chr(28) . 'I<X>'> for all characters I<X>.
+
+To write platform-independent code, you must use C<\N{I<NAME>}> instead, like
+C<\N{ESCAPE}> or C<\N{U+001B}>, see L<charnames>.
+
+Mnemonic: I<c>ontrol character.
+
+=head4 Example
+
+ $str =~ /\cK/; # Matches if $str contains a vertical tab (control-K).
+
+=head3 Named or numbered characters
+
+Unicode characters have a Unicode name and numeric ordinal value. Use the
+C<\N{}> construct to specify a character by either of these values.
+
+To specify by name, the name of the character goes between the curly braces.
+In this case, you have to C<use charnames> to load the Unicode names of the
+characters, otherwise Perl will complain.
+
+To specify by Unicode ordinal number, use the form
+C<\N{U+I<wide hex character>}>, where I<wide hex character> is a number in
+hexadecimal that gives the ordinal number that Unicode has assigned to the
+desired character. It is customary (but not required) to use leading zeros to
+pad the number to 4 digits. Thus C<\N{U+0041}> means
+C<Latin Capital Letter A>, and you will rarely see it written without the two
+leading zeros. C<\N{U+0041}> means "A" even on EBCDIC machines (where the
+ordinal value of "A" is not 0x41).
+
+It is even possible to give your own names to characters, and even to short
+sequences of characters. For details, see L<charnames>.
+
+(There is an expanded internal form that you may see in debug output:
+C<\N{U+I<wide hex character>.I<wide hex character>...}>.
+The C<...> means any number of these I<wide hex character>s separated by dots.
+This represents the sequence formed by the characters. This is an internal
+form only, subject to change, and you should not try to use it yourself.)
+
+Mnemonic: I<N>amed character.
+
+Note that a character that is expressed as a named or numbered character is
+considered as a character without special meaning by the regex engine, and will
+match "as is".
+
+=head4 Example
+
+ use charnames ':full'; # Loads the Unicode names.
+ $str =~ /\N{THAI CHARACTER SO SO}/; # Matches the Thai SO SO character
+
+ use charnames 'Cyrillic'; # Loads Cyrillic names.
+ $str =~ /\N{ZHE}\N{KA}/; # Match "ZHE" followed by "KA".
+
+=head3 Octal escapes
+
+Octal escapes consist of a backslash followed by two or three octal digits
+matching the code point of the character you want to use. This allows for
+512 characters (C<\00> up to C<\777>) that can be expressed this way (but
+anything above C<\377> is deprecated).
+Enough in pre-Unicode days, but most Unicode characters cannot be escaped
+this way.
+
+Note that a character that is expressed as an octal escape is considered
+as a character without special meaning by the regex engine, and will match
+"as is".
+
+=head4 Examples (assuming an ASCII platform)
+
+ $str = "Perl";
+ $str =~ /\120/; # Match, "\120" is "P".
+ $str =~ /\120+/; # Match, "\120" is "P", it is repeated at least once.
+ $str =~ /P\053/; # No match, "\053" is "+" and taken literally.
+
+=head4 Caveat
+
+Octal escapes potentially clash with backreferences. They both consist
+of a backslash followed by numbers. So Perl has to use heuristics to
+determine whether it is a backreference or an octal escape. Perl uses
+the following rules:
+
+=over 4
+
+=item 1
+
+If the backslash is followed by a single digit, it's a backreference.
+
+=item 2
+
+If the first digit following the backslash is a 0, it's an octal escape.
+
+=item 3
+
+If the number following the backslash is N (in decimal), and Perl already has
+seen N capture groups, Perl will consider this to be a backreference.
+Otherwise, it will consider it to be an octal escape. Note that if N has more
+than three digits, Perl only takes the first three for the octal escape;
+the rest are matched as is.
+
+ my $pat = "(" x 999;
+ $pat .= "a";
+ $pat .= ")" x 999;
+ /^($pat)\1000$/; # Matches 'aa'; there are 1000 capture groups.
+ /^$pat\1000$/; # Matches 'a@0'; there are 999 capture groups
+ # and \1000 is seen as \100 (a '@') and a '0'.
+
+=back
+
+=head3 Hexadecimal escapes
+
+Hexadecimal escapes start with C<\x> and are then either followed by a
+two digit hexadecimal number, or a hexadecimal number of arbitrary length
+surrounded by curly braces. The hexadecimal number is the code point of
+the character you want to express.
+
+Note that a character that is expressed as a hexadecimal escape is considered
+as a character without special meaning by the regex engine, and will match
+"as is".
+
+Mnemonic: heI<x>adecimal.
+
+=head4 Examples (assuming an ASCII platform)
+
+ $str = "Perl";
+ $str =~ /\x50/; # Match, "\x50" is "P".
+ $str =~ /\x50+/; # Match, "\x50" is "P", it is repeated at least once.
+ $str =~ /P\x2B/; # No match, "\x2B" is "+" and taken literally.
+
+ /\x{2603}\x{2602}/ # Snowman with an umbrella.
+ # The Unicode character 2603 is a snowman,
+ # the Unicode character 2602 is an umbrella.
+ /\x{263B}/ # Black smiling face.
+ /\x{263b}/ # Same, the hex digits A - F are case insensitive.
+
+=head2 Modifiers
+
+A number of backslash sequences have to do with changing the character,
+or characters following them. C<\l> will lowercase the character following
+it, while C<\u> will uppercase (or, more accurately, titlecase) the
+character following it. (They perform similar functionality as the
+functions C<lcfirst> and C<ucfirst>).
+
+To uppercase or lowercase several characters, one might want to use
+C<\L> or C<\U>, which will lowercase/uppercase all characters following
+them, until either the end of the pattern, or the next occurrence of
+C<\E>, whatever comes first. They perform similar functionality as the
+functions C<lc> and C<uc> do.
+
+C<\Q> is used to escape all characters following, up to the next C<\E>
+or the end of the pattern. C<\Q> adds a backslash to any character that
+isn't a letter, digit or underscore. This will ensure that any character
+between C<\Q> and C<\E> is matched literally, and will not be interpreted
+by the regexp engine.
+
+Mnemonic: I<L>owercase, I<U>ppercase, I<Q>uotemeta, I<E>nd.
+
+=head4 Examples
+
+ $sid = "sid";
+ $greg = "GrEg";
+ $miranda = "(Miranda)";
+ $str =~ /\u$sid/; # Matches 'Sid'
+ $str =~ /\L$greg/; # Matches 'greg'
+ $str =~ /\Q$miranda\E/; # Matches '(Miranda)', as if the pattern
+ # had been written as /\(Miranda\)/
+
+=head2 Character classes
+
+Perl regular expressions have a large range of character classes. Some of
+the character classes are written as a backslash sequence. We will briefly
+discuss those here; full details of character classes can be found in
+L<perlrecharclass>.
+
+C<\w> is a character class that matches any single I<word> character (letters,
+digits, underscore). C<\d> is a character class that matches any decimal digit,
+while the character class C<\s> matches any whitespace character.
+New in perl 5.10.0 are the classes C<\h> and C<\v> which match horizontal
+and vertical whitespace characters.
+
+The uppercase variants (C<\W>, C<\D>, C<\S>, C<\H>, and C<\V>) are
+character classes that match any character that isn't a word character,
+digit, whitespace, horizontal whitespace nor vertical whitespace.
+
+Mnemonics: I<w>ord, I<d>igit, I<s>pace, I<h>orizontal, I<v>ertical.
+
+=head3 Unicode classes
+
+C<\pP> (where C<P> is a single letter) and C<\p{Property}> are used to
+match a character that matches the given Unicode property; properties
+include things like "letter", or "thai character". Capitalizing the
+sequence to C<\PP> and C<\P{Property}> make the sequence match a character
+that doesn't match the given Unicode property. For more details, see
+L<perlrecharclass/Backslash sequences> and
+L<perlunicode/Unicode Character Properties>.
+
+Mnemonic: I<p>roperty.
+
+
+=head2 Referencing
+
+If capturing parenthesis are used in a regular expression, we can refer
+to the part of the source string that was matched, and match exactly the
+same thing. There are three ways of referring to such I<backreference>:
+absolutely, relatively, and by name.
+
+=for later add link to perlrecapture
+
+=head3 Absolute referencing
+
+A backslash sequence that starts with a backslash and is followed by a
+number is an absolute reference (but be aware of the caveat mentioned above).
+If the number is I<N>, it refers to the Nth set of parentheses - whatever
+has been matched by that set of parenthesis has to be matched by the C<\N>
+as well.
+
+=head4 Examples
+
+ /(\w+) \1/; # Finds a duplicated word, (e.g. "cat cat").
+ /(.)(.)\2\1/; # Match a four letter palindrome (e.g. "ABBA").
+
+
+=head3 Relative referencing
+
+New in perl 5.10.0 is a different way of referring to capture buffers: C<\g>.
+C<\g> takes a number as argument, with the number in curly braces (the
+braces are optional). If the number (N) does not have a sign, it's a reference
+to the Nth capture group (so C<\g{2}> is equivalent to C<\2> - except that
+C<\g> always refers to a capture group and will never be seen as an octal
+escape). If the number is negative, the reference is relative, referring to
+the Nth group before the C<\g{-N}>.
+
+The big advantage of C<\g{-N}> is that it makes it much easier to write
+patterns with references that can be interpolated in larger patterns,
+even if the larger pattern also contains capture groups.
+
+Mnemonic: I<g>roup.
+
+=head4 Examples
+
+ /(A) # Buffer 1
+ ( # Buffer 2
+ (B) # Buffer 3
+ \g{-1} # Refers to buffer 3 (B)
+ \g{-3} # Refers to buffer 1 (A)
+ )
+ /x; # Matches "ABBA".
+
+ my $qr = qr /(.)(.)\g{-2}\g{-1}/; # Matches 'abab', 'cdcd', etc.
+ /$qr$qr/ # Matches 'ababcdcd'.
+
+=head3 Named referencing
+
+Also new in perl 5.10.0 is the use of named capture buffers, which can be
+referred to by name. This is done with C<\g{name}>, which is a
+backreference to the capture buffer with the name I<name>.
+
+To be compatible with .Net regular expressions, C<\g{name}> may also be
+written as C<\k{name}>, C<< \k<name> >> or C<\k'name'>.
+
+Note that C<\g{}> has the potential to be ambiguous, as it could be a named
+reference, or an absolute or relative reference (if its argument is numeric).
+However, names are not allowed to start with digits, nor are they allowed to
+contain a hyphen, so there is no ambiguity.
+
+=head4 Examples
+
+ /(?<word>\w+) \g{word}/ # Finds duplicated word, (e.g. "cat cat")
+ /(?<word>\w+) \k{word}/ # Same.
+ /(?<word>\w+) \k<word>/ # Same.
+ /(?<letter1>.)(?<letter2>.)\g{letter2}\g{letter1}/
+ # Match a four letter palindrome (e.g. "ABBA")
+
+=head2 Assertions
+
+Assertions are conditions that have to be true; they don't actually
+match parts of the substring. There are six assertions that are written as
+backslash sequences.
+
+=over 4
+
+=item \A
+
+C<\A> only matches at the beginning of the string. If the C</m> modifier
+isn't used, then C</\A/> is equivalent with C</^/>. However, if the C</m>
+modifier is used, then C</^/> matches internal newlines, but the meaning
+of C</\A/> isn't changed by the C</m> modifier. C<\A> matches at the beginning
+of the string regardless whether the C</m> modifier is used.
+
+=item \z, \Z
+
+C<\z> and C<\Z> match at the end of the string. If the C</m> modifier isn't
+used, then C</\Z/> is equivalent with C</$/>, that is, it matches at the
+end of the string, or before the newline at the end of the string. If the
+C</m> modifier is used, then C</$/> matches at internal newlines, but the
+meaning of C</\Z/> isn't changed by the C</m> modifier. C<\Z> matches at
+the end of the string (or just before a trailing newline) regardless whether
+the C</m> modifier is used.
+
+C<\z> is just like C<\Z>, except that it will not match before a trailing
+newline. C<\z> will only match at the end of the string - regardless of the
+modifiers used, and not before a newline.
+
+=item \G
+
+C<\G> is usually only used in combination with the C</g> modifier. If the
+C</g> modifier is used (and the match is done in scalar context), Perl will
+remember where in the source string the last match ended, and the next time,
+it will start the match from where it ended the previous time.
+
+C<\G> matches the point where the previous match ended, or the beginning
+of the string if there was no previous match.
+
+=for later add link to perlremodifiers
+
+Mnemonic: I<G>lobal.
+
+=item \b, \B
+
+C<\b> matches at any place between a word and a non-word character; C<\B>
+matches at any place between characters where C<\b> doesn't match. C<\b>
+and C<\B> assume there's a non-word character before the beginning and after
+the end of the source string; so C<\b> will match at the beginning (or end)
+of the source string if the source string begins (or ends) with a word
+character. Otherwise, C<\B> will match.
+
+Mnemonic: I<b>oundary.
+
+=back
+
+=head4 Examples
+
+ "cat" =~ /\Acat/; # Match.
+ "cat" =~ /cat\Z/; # Match.
+ "cat\n" =~ /cat\Z/; # Match.
+ "cat\n" =~ /cat\z/; # No match.
+
+ "cat" =~ /\bcat\b/; # Matches.
+ "cats" =~ /\bcat\b/; # No match.
+ "cat" =~ /\bcat\B/; # No match.
+ "cats" =~ /\bcat\B/; # Match.
+
+ while ("cat dog" =~ /(\w+)/g) {
+ print $1; # Prints 'catdog'
+ }
+ while ("cat dog" =~ /\G(\w+)/g) {
+ print $1; # Prints 'cat'
+ }
+
+=head2 Misc
+
+Here we document the backslash sequences that don't fall in one of the
+categories above. They are:
+
+=over 4
+
+=item \C
+
+C<\C> always matches a single octet, even if the source string is encoded
+in UTF-8 format, and the character to be matched is a multi-octet character.
+C<\C> was introduced in perl 5.6.
+
+Mnemonic: oI<C>tet.
+
+=item \K
+
+This is new in perl 5.10.0. Anything that is matched left of C<\K> is
+not included in C<$&> - and will not be replaced if the pattern is
+used in a substitution. This will allow you to write C<s/PAT1 \K PAT2/REPL/x>
+instead of C<s/(PAT1) PAT2/${1}REPL/x> or C<s/(?<=PAT1) PAT2/REPL/x>.
+
+Mnemonic: I<K>eep.
+
+=item \N
+
+This is a new experimental feature in perl 5.12.0. It matches any character
+that is not a newline. It is a short-hand for writing C<[^\n]>, and is
+identical to the C<.> metasymbol, except under the C</s> flag, which changes
+the meaning of C<.>, but not C<\N>.
+
+Note that C<\N{...}> can mean a
+L<named or numbered character|/Named or numbered characters>.
+
+Mnemonic: Complement of I<\n>.
+
+=item \R
+X<\R>
+
+C<\R> matches a I<generic newline>, that is, anything that is considered
+a newline by Unicode. This includes all characters matched by C<\v>
+(vertical whitespace), and the multi character sequence C<"\x0D\x0A">
+(carriage return followed by a line feed, aka the network newline, or
+the newline used in Windows text files). C<\R> is equivalent to
+C<< (?>\x0D\x0A)|\v) >>. Since C<\R> can match a sequence of more than one
+character, it cannot be put inside a bracketed character class; C</[\R]/> is an
+error; use C<\v> instead. C<\R> was introduced in perl 5.10.0.
+
+Mnemonic: none really. C<\R> was picked because PCRE already uses C<\R>,
+and more importantly because Unicode recommends such a regular expression
+metacharacter, and suggests C<\R> as the notation.
+
+=item \X
+X<\X>
+
+This matches a Unicode I<extended grapheme cluster>.
+
+C<\X> matches quite well what normal (non-Unicode-programmer) usage
+would consider a single character. As an example, consider a G with some sort
+of diacritic mark, such as an arrow. There is no such single character in
+Unicode, but one can be composed by using a G followed by a Unicode "COMBINING
+UPWARDS ARROW BELOW", and would be displayed by Unicode-aware software as if it
+were a single character.
+
+Mnemonic: eI<X>tended Unicode character.
+
+=back
+
+=head4 Examples
+
+ "\x{256}" =~ /^\C\C$/; # Match as chr (256) takes 2 octets in UTF-8.
+
+ $str =~ s/foo\Kbar/baz/g; # Change any 'bar' following a 'foo' to 'baz'.
+ $str =~ s/(.)\K\1//g; # Delete duplicated characters.
+
+ "\n" =~ /^\R$/; # Match, \n is a generic newline.
+ "\r" =~ /^\R$/; # Match, \r is a generic newline.
+ "\r\n" =~ /^\R$/; # Match, \r\n is a generic newline.
+
+ "P\x{0307}" =~ /^\X$/ # \X matches a P with a dot above.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlrecharclass.pod b/Master/tlpkg/tlperl/lib/pods/perlrecharclass.pod
new file mode 100644
index 00000000000..a9b5ea37c74
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlrecharclass.pod
@@ -0,0 +1,699 @@
+=head1 NAME
+X<character class>
+
+perlrecharclass - Perl Regular Expression Character Classes
+
+=head1 DESCRIPTION
+
+The top level documentation about Perl regular expressions
+is found in L<perlre>.
+
+This manual page discusses the syntax and use of character
+classes in Perl regular expressions.
+
+A character class is a way of denoting a set of characters
+in such a way that one character of the set is matched.
+It's important to remember that: matching a character class
+consumes exactly one character in the source string. (The source
+string is the string the regular expression is matched against.)
+
+There are three types of character classes in Perl regular
+expressions: the dot, backslash sequences, and the form enclosed in square
+brackets. Keep in mind, though, that often the term "character class" is used
+to mean just the bracketed form. Certainly, most Perl documentation does that.
+
+=head2 The dot
+
+The dot (or period), C<.> is probably the most used, and certainly
+the most well-known character class. By default, a dot matches any
+character, except for the newline. The default can be changed to
+add matching the newline by using the I<single line> modifier: either
+for the entire regular expression with the C</s> modifier, or
+locally with C<(?s)>. (The experimental C<\N> backslash sequence, described
+below, matches any character except newline without regard to the
+I<single line> modifier.)
+
+Here are some examples:
+
+ "a" =~ /./ # Match
+ "." =~ /./ # Match
+ "" =~ /./ # No match (dot has to match a character)
+ "\n" =~ /./ # No match (dot does not match a newline)
+ "\n" =~ /./s # Match (global 'single line' modifier)
+ "\n" =~ /(?s:.)/ # Match (local 'single line' modifier)
+ "ab" =~ /^.$/ # No match (dot matches one character)
+
+=head2 Backslash sequences
+X<\w> X<\W> X<\s> X<\S> X<\d> X<\D> X<\p> X<\P>
+X<\N> X<\v> X<\V> X<\h> X<\H>
+X<word> X<whitespace>
+
+A backslash sequence is a sequence of characters, the first one of which is a
+backslash. Perl ascribes special meaning to many such sequences, and some of
+these are character classes. That is, they match a single character each,
+provided that the character belongs to the specific set of characters defined
+by the sequence.
+
+Here's a list of the backslash sequences that are character classes. They
+are discussed in more detail below. (For the backslash sequences that aren't
+character classes, see L<perlrebackslash>.)
+
+ \d Match a decimal digit character.
+ \D Match a non-decimal-digit character.
+ \w Match a "word" character.
+ \W Match a non-"word" character.
+ \s Match a whitespace character.
+ \S Match a non-whitespace character.
+ \h Match a horizontal whitespace character.
+ \H Match a character that isn't horizontal whitespace.
+ \v Match a vertical whitespace character.
+ \V Match a character that isn't vertical whitespace.
+ \N Match a character that isn't a newline. Experimental.
+ \pP, \p{Prop} Match a character that has the given Unicode property.
+ \PP, \P{Prop} Match a character that doesn't have the Unicode property
+
+=head3 Digits
+
+C<\d> matches a single character that is considered to be a decimal I<digit>.
+What is considered a decimal digit depends on the internal encoding of the
+source string and the locale that is in effect. If the source string is in
+UTF-8 format, C<\d> not only matches the digits '0' - '9', but also Arabic,
+Devanagari and digits from other languages. Otherwise, if there is a locale in
+effect, it will match whatever characters the locale considers decimal digits.
+Without a locale, C<\d> matches just the digits '0' to '9'.
+See L</Locale, EBCDIC, Unicode and UTF-8>.
+
+Unicode digits may cause some confusion, and some security issues. In UTF-8
+strings, C<\d> matches the same characters matched by
+C<\p{General_Category=Decimal_Number}>, or synonymously,
+C<\p{General_Category=Digit}>. Starting with Unicode version 4.1, this is the
+same set of characters matched by C<\p{Numeric_Type=Decimal}>.
+
+But Unicode also has a different property with a similar name,
+C<\p{Numeric_Type=Digit}>, which matches a completely different set of
+characters. These characters are things such as subscripts.
+
+The design intent is for C<\d> to match all the digits (and no other characters)
+that can be used with "normal" big-endian positional decimal syntax, whereby a
+sequence of such digits {N0, N1, N2, ...Nn} has the numeric value (...(N0 * 10
++ N1) * 10 + N2) * 10 ... + Nn). In Unicode 5.2, the Tamil digits (U+0BE6 -
+U+0BEF) can also legally be used in old-style Tamil numbers in which they would
+appear no more than one in a row, separated by characters that mean "times 10",
+"times 100", etc. (See L<http://www.unicode.org/notes/tn21>.)
+
+Some of the non-European digits that C<\d> matches look like European ones, but
+have different values. For example, BENGALI DIGIT FOUR (U+09A) looks very much
+like an ASCII DIGIT EIGHT (U+0038).
+
+It may be useful for security purposes for an application to require that all
+digits in a row be from the same script. See L<Unicode::UCD/charscript()>.
+
+Any character that isn't matched by C<\d> will be matched by C<\D>.
+
+=head3 Word characters
+
+A C<\w> matches a single alphanumeric character (an alphabetic character, or a
+decimal digit) or an underscore (C<_>), not a whole word. To match a whole
+word, use C<\w+>. This isn't the same thing as matching an English word, but
+is the same as a string of Perl-identifier characters. What is considered a
+word character depends on the internal
+encoding of the string and the locale or EBCDIC code page that is in effect. If
+it's in UTF-8 format, C<\w> matches those characters that are considered word
+characters in the Unicode database. That is, it not only matches ASCII letters,
+but also Thai letters, Greek letters, etc. If the source string isn't in UTF-8
+format, C<\w> matches those characters that are considered word characters by
+the current locale or EBCDIC code page. Without a locale or EBCDIC code page,
+C<\w> matches the ASCII letters, digits and the underscore.
+See L</Locale, EBCDIC, Unicode and UTF-8>.
+
+There are a number of security issues with the full Unicode list of word
+characters. See L<http://unicode.org/reports/tr36>.
+
+Also, for a somewhat finer-grained set of characters that are in programming
+language identifiers beyond the ASCII range, you may wish to instead use the
+more customized Unicode properties, "ID_Start", ID_Continue", "XID_Start", and
+"XID_Continue". See L<http://unicode.org/reports/tr31>.
+
+Any character that isn't matched by C<\w> will be matched by C<\W>.
+
+=head3 Whitespace
+
+C<\s> matches any single character that is considered whitespace. The exact
+set of characters matched by C<\s> depends on whether the source string is in
+UTF-8 format and the locale or EBCDIC code page that is in effect. If it's in
+UTF-8 format, C<\s> matches what is considered whitespace in the Unicode
+database; the complete list is in the table below. Otherwise, if there is a
+locale or EBCDIC code page in effect, C<\s> matches whatever is considered
+whitespace by the current locale or EBCDIC code page. Without a locale or
+EBCDIC code page, C<\s> matches the horizontal tab (C<\t>), the newline
+(C<\n>), the form feed (C<\f>), the carriage return (C<\r>), and the space.
+(Note that it doesn't match the vertical tab, C<\cK>.) Perhaps the most notable
+possible surprise is that C<\s> matches a non-breaking space only if the
+non-breaking space is in a UTF-8 encoded string or the locale or EBCDIC code
+page that is in effect has that character.
+See L</Locale, EBCDIC, Unicode and UTF-8>.
+
+Any character that isn't matched by C<\s> will be matched by C<\S>.
+
+C<\h> will match any character that is considered horizontal whitespace;
+this includes the space and the tab characters and a number other characters,
+all of which are listed in the table below. C<\H> will match any character
+that is not considered horizontal whitespace.
+
+C<\v> will match any character that is considered vertical whitespace;
+this includes the carriage return and line feed characters (newline) plus several
+other characters, all listed in the table below.
+C<\V> will match any character that is not considered vertical whitespace.
+
+C<\R> matches anything that can be considered a newline under Unicode
+rules. It's not a character class, as it can match a multi-character
+sequence. Therefore, it cannot be used inside a bracketed character
+class; use C<\v> instead (vertical whitespace).
+Details are discussed in L<perlrebackslash>.
+
+Note that unlike C<\s>, C<\d> and C<\w>, C<\h> and C<\v> always match
+the same characters, regardless whether the source string is in UTF-8
+format or not. The set of characters they match is also not influenced
+by locale nor EBCDIC code page.
+
+One might think that C<\s> is equivalent to C<[\h\v]>. This is not true. The
+vertical tab (C<"\x0b">) is not matched by C<\s>, it is however considered
+vertical whitespace. Furthermore, if the source string is not in UTF-8 format,
+and any locale or EBCDIC code page that is in effect doesn't include them, the
+next line (ASCII-platform C<"\x85">) and the no-break space (ASCII-platform
+C<"\xA0">) characters are not matched by C<\s>, but are by C<\v> and C<\h>
+respectively. If the source string is in UTF-8 format, both the next line and
+the no-break space are matched by C<\s>.
+
+The following table is a complete listing of characters matched by
+C<\s>, C<\h> and C<\v> as of Unicode 5.2.
+
+The first column gives the code point of the character (in hex format),
+the second column gives the (Unicode) name. The third column indicates
+by which class(es) the character is matched (assuming no locale or EBCDIC code
+page is in effect that changes the C<\s> matching).
+
+ 0x00009 CHARACTER TABULATION h s
+ 0x0000a LINE FEED (LF) vs
+ 0x0000b LINE TABULATION v
+ 0x0000c FORM FEED (FF) vs
+ 0x0000d CARRIAGE RETURN (CR) vs
+ 0x00020 SPACE h s
+ 0x00085 NEXT LINE (NEL) vs [1]
+ 0x000a0 NO-BREAK SPACE h s [1]
+ 0x01680 OGHAM SPACE MARK h s
+ 0x0180e MONGOLIAN VOWEL SEPARATOR h s
+ 0x02000 EN QUAD h s
+ 0x02001 EM QUAD h s
+ 0x02002 EN SPACE h s
+ 0x02003 EM SPACE h s
+ 0x02004 THREE-PER-EM SPACE h s
+ 0x02005 FOUR-PER-EM SPACE h s
+ 0x02006 SIX-PER-EM SPACE h s
+ 0x02007 FIGURE SPACE h s
+ 0x02008 PUNCTUATION SPACE h s
+ 0x02009 THIN SPACE h s
+ 0x0200a HAIR SPACE h s
+ 0x02028 LINE SEPARATOR vs
+ 0x02029 PARAGRAPH SEPARATOR vs
+ 0x0202f NARROW NO-BREAK SPACE h s
+ 0x0205f MEDIUM MATHEMATICAL SPACE h s
+ 0x03000 IDEOGRAPHIC SPACE h s
+
+=over 4
+
+=item [1]
+
+NEXT LINE and NO-BREAK SPACE only match C<\s> if the source string is in
+UTF-8 format, or the locale or EBCDIC code page that is in effect includes them.
+
+=back
+
+It is worth noting that C<\d>, C<\w>, etc, match single characters, not
+complete numbers or words. To match a number (that consists of integers),
+use C<\d+>; to match a word, use C<\w+>.
+
+=head3 \N
+
+C<\N> is new in 5.12, and is experimental. It, like the dot, will match any
+character that is not a newline. The difference is that C<\N> is not influenced
+by the I<single line> regular expression modifier (see L</The dot> above). Note
+that the form C<\N{...}> may mean something completely different. When the
+C<{...}> is a L<quantifier|perlre/Quantifiers>, it means to match a non-newline
+character that many times. For example, C<\N{3}> means to match 3
+non-newlines; C<\N{5,}> means to match 5 or more non-newlines. But if C<{...}>
+is not a legal quantifier, it is presumed to be a named character. See
+L<charnames> for those. For example, none of C<\N{COLON}>, C<\N{4F}>, and
+C<\N{F4}> contain legal quantifiers, so Perl will try to find characters whose
+names are, respectively, C<COLON>, C<4F>, and C<F4>.
+
+=head3 Unicode Properties
+
+C<\pP> and C<\p{Prop}> are character classes to match characters that fit given
+Unicode properties. One letter property names can be used in the C<\pP> form,
+with the property name following the C<\p>, otherwise, braces are required.
+When using braces, there is a single form, which is just the property name
+enclosed in the braces, and a compound form which looks like C<\p{name=value}>,
+which means to match if the property "name" for the character has the particular
+"value".
+For instance, a match for a number can be written as C</\pN/> or as
+C</\p{Number}/>, or as C</\p{Number=True}/>.
+Lowercase letters are matched by the property I<Lowercase_Letter> which
+has as short form I<Ll>. They need the braces, so are written as C</\p{Ll}/> or
+C</\p{Lowercase_Letter}/>, or C</\p{General_Category=Lowercase_Letter}/>
+(the underscores are optional).
+C</\pLl/> is valid, but means something different.
+It matches a two character string: a letter (Unicode property C<\pL>),
+followed by a lowercase C<l>.
+
+For more details, see L<perlunicode/Unicode Character Properties>; for a
+complete list of possible properties, see
+L<perluniprops/Properties accessible through \p{} and \P{}>.
+It is also possible to define your own properties. This is discussed in
+L<perlunicode/User-Defined Character Properties>.
+
+
+=head4 Examples
+
+ "a" =~ /\w/ # Match, "a" is a 'word' character.
+ "7" =~ /\w/ # Match, "7" is a 'word' character as well.
+ "a" =~ /\d/ # No match, "a" isn't a digit.
+ "7" =~ /\d/ # Match, "7" is a digit.
+ " " =~ /\s/ # Match, a space is whitespace.
+ "a" =~ /\D/ # Match, "a" is a non-digit.
+ "7" =~ /\D/ # No match, "7" is not a non-digit.
+ " " =~ /\S/ # No match, a space is not non-whitespace.
+
+ " " =~ /\h/ # Match, space is horizontal whitespace.
+ " " =~ /\v/ # No match, space is not vertical whitespace.
+ "\r" =~ /\v/ # Match, a return is vertical whitespace.
+
+ "a" =~ /\pL/ # Match, "a" is a letter.
+ "a" =~ /\p{Lu}/ # No match, /\p{Lu}/ matches upper case letters.
+
+ "\x{0e0b}" =~ /\p{Thai}/ # Match, \x{0e0b} is the character
+ # 'THAI CHARACTER SO SO', and that's in
+ # Thai Unicode class.
+ "a" =~ /\P{Lao}/ # Match, as "a" is not a Laotian character.
+
+
+=head2 Bracketed Character Classes
+
+The third form of character class you can use in Perl regular expressions
+is the bracketed character class. In its simplest form, it lists the characters
+that may be matched, surrounded by square brackets, like this: C<[aeiou]>.
+This matches one of C<a>, C<e>, C<i>, C<o> or C<u>. Like the other
+character classes, exactly one character will be matched. To match
+a longer string consisting of characters mentioned in the character
+class, follow the character class with a L<quantifier|perlre/Quantifiers>. For
+instance, C<[aeiou]+> matches a string of one or more lowercase English vowels.
+
+Repeating a character in a character class has no
+effect; it's considered to be in the set only once.
+
+Examples:
+
+ "e" =~ /[aeiou]/ # Match, as "e" is listed in the class.
+ "p" =~ /[aeiou]/ # No match, "p" is not listed in the class.
+ "ae" =~ /^[aeiou]$/ # No match, a character class only matches
+ # a single character.
+ "ae" =~ /^[aeiou]+$/ # Match, due to the quantifier.
+
+=head3 Special Characters Inside a Bracketed Character Class
+
+Most characters that are meta characters in regular expressions (that
+is, characters that carry a special meaning like C<.>, C<*>, or C<(>) lose
+their special meaning and can be used inside a character class without
+the need to escape them. For instance, C<[()]> matches either an opening
+parenthesis, or a closing parenthesis, and the parens inside the character
+class don't group or capture.
+
+Characters that may carry a special meaning inside a character class are:
+C<\>, C<^>, C<->, C<[> and C<]>, and are discussed below. They can be
+escaped with a backslash, although this is sometimes not needed, in which
+case the backslash may be omitted.
+
+The sequence C<\b> is special inside a bracketed character class. While
+outside the character class, C<\b> is an assertion indicating a point
+that does not have either two word characters or two non-word characters
+on either side, inside a bracketed character class, C<\b> matches a
+backspace character.
+
+The sequences
+C<\a>,
+C<\c>,
+C<\e>,
+C<\f>,
+C<\n>,
+C<\N{I<NAME>}>,
+C<\N{U+I<wide hex char>}>,
+C<\r>,
+C<\t>,
+and
+C<\x>
+are also special and have the same meanings as they do outside a bracketed character
+class.
+
+Also, a backslash followed by two or three octal digits is considered an octal
+number.
+
+A C<[> is not special inside a character class, unless it's the start of a
+POSIX character class (see L</POSIX Character Classes> below). It normally does
+not need escaping.
+
+A C<]> is normally either the end of a POSIX character class (see
+L</POSIX Character Classes> below), or it signals the end of the bracketed
+character class. If you want to include a C<]> in the set of characters, you
+must generally escape it.
+However, if the C<]> is the I<first> (or the second if the first
+character is a caret) character of a bracketed character class, it
+does not denote the end of the class (as you cannot have an empty class)
+and is considered part of the set of characters that can be matched without
+escaping.
+
+Examples:
+
+ "+" =~ /[+?*]/ # Match, "+" in a character class is not special.
+ "\cH" =~ /[\b]/ # Match, \b inside in a character class
+ # is equivalent to a backspace.
+ "]" =~ /[][]/ # Match, as the character class contains.
+ # both [ and ].
+ "[]" =~ /[[]]/ # Match, the pattern contains a character class
+ # containing just ], and the character class is
+ # followed by a ].
+
+=head3 Character Ranges
+
+It is not uncommon to want to match a range of characters. Luckily, instead
+of listing all the characters in the range, one may use the hyphen (C<->).
+If inside a bracketed character class you have two characters separated
+by a hyphen, it's treated as if all the characters between the two are in
+the class. For instance, C<[0-9]> matches any ASCII digit, and C<[a-m]>
+matches any lowercase letter from the first half of the ASCII alphabet.
+
+Note that the two characters on either side of the hyphen are not
+necessary both letters or both digits. Any character is possible,
+although not advisable. C<['-?]> contains a range of characters, but
+most people will not know which characters that will be. Furthermore,
+such ranges may lead to portability problems if the code has to run on
+a platform that uses a different character set, such as EBCDIC.
+
+If a hyphen in a character class cannot syntactically be part of a range, for
+instance because it is the first or the last character of the character class,
+or if it immediately follows a range, the hyphen isn't special, and will be
+considered a character that is to be matched literally. You have to escape the
+hyphen with a backslash if you want to have a hyphen in your set of characters
+to be matched, and its position in the class is such that it could be
+considered part of a range.
+
+Examples:
+
+ [a-z] # Matches a character that is a lower case ASCII letter.
+ [a-fz] # Matches any letter between 'a' and 'f' (inclusive) or
+ # the letter 'z'.
+ [-z] # Matches either a hyphen ('-') or the letter 'z'.
+ [a-f-m] # Matches any letter between 'a' and 'f' (inclusive), the
+ # hyphen ('-'), or the letter 'm'.
+ ['-?] # Matches any of the characters '()*+,-./0123456789:;<=>?
+ # (But not on an EBCDIC platform).
+
+
+=head3 Negation
+
+It is also possible to instead list the characters you do not want to
+match. You can do so by using a caret (C<^>) as the first character in the
+character class. For instance, C<[^a-z]> matches a character that is not a
+lowercase ASCII letter.
+
+This syntax make the caret a special character inside a bracketed character
+class, but only if it is the first character of the class. So if you want
+to have the caret as one of the characters you want to match, you either
+have to escape the caret, or not list it first.
+
+Examples:
+
+ "e" =~ /[^aeiou]/ # No match, the 'e' is listed.
+ "x" =~ /[^aeiou]/ # Match, as 'x' isn't a lowercase vowel.
+ "^" =~ /[^^]/ # No match, matches anything that isn't a caret.
+ "^" =~ /[x^]/ # Match, caret is not special here.
+
+=head3 Backslash Sequences
+
+You can put any backslash sequence character class (with the exception of
+C<\N>) inside a bracketed character class, and it will act just
+as if you put all the characters matched by the backslash sequence inside the
+character class. For instance, C<[a-f\d]> will match any decimal digit, or any
+of the lowercase letters between 'a' and 'f' inclusive.
+
+C<\N> within a bracketed character class must be of the forms C<\N{I<name>}>
+or C<\N{U+I<wide hex char>}>, and NOT be the form that matches non-newlines,
+for the same reason that a dot C<.> inside a bracketed character class loses
+its special meaning: it matches nearly anything, which generally isn't what you
+want to happen.
+
+
+Examples:
+
+ /[\p{Thai}\d]/ # Matches a character that is either a Thai
+ # character, or a digit.
+ /[^\p{Arabic}()]/ # Matches a character that is neither an Arabic
+ # character, nor a parenthesis.
+
+Backslash sequence character classes cannot form one of the endpoints
+of a range. Thus, you can't say:
+
+ /[\p{Thai}-\d]/ # Wrong!
+
+=head3 POSIX Character Classes
+X<character class> X<\p> X<\p{}>
+X<alpha> X<alnum> X<ascii> X<blank> X<cntrl> X<digit> X<graph>
+X<lower> X<print> X<punct> X<space> X<upper> X<word> X<xdigit>
+
+POSIX character classes have the form C<[:class:]>, where I<class> is
+name, and the C<[:> and C<:]> delimiters. POSIX character classes only appear
+I<inside> bracketed character classes, and are a convenient and descriptive
+way of listing a group of characters, though they currently suffer from
+portability issues (see below and L<Locale, EBCDIC, Unicode and UTF-8>).
+
+Be careful about the syntax,
+
+ # Correct:
+ $string =~ /[[:alpha:]]/
+
+ # Incorrect (will warn):
+ $string =~ /[:alpha:]/
+
+The latter pattern would be a character class consisting of a colon,
+and the letters C<a>, C<l>, C<p> and C<h>.
+POSIX character classes can be part of a larger bracketed character class. For
+example,
+
+ [01[:alpha:]%]
+
+is valid and matches '0', '1', any alphabetic character, and the percent sign.
+
+Perl recognizes the following POSIX character classes:
+
+ alpha Any alphabetical character ("[A-Za-z]").
+ alnum Any alphanumerical character. ("[A-Za-z0-9]")
+ ascii Any character in the ASCII character set.
+ blank A GNU extension, equal to a space or a horizontal tab ("\t").
+ cntrl Any control character. See Note [2] below.
+ digit Any decimal digit ("[0-9]"), equivalent to "\d".
+ graph Any printable character, excluding a space. See Note [3] below.
+ lower Any lowercase character ("[a-z]").
+ print Any printable character, including a space. See Note [4] below.
+ punct Any graphical character excluding "word" characters. Note [5].
+ space Any whitespace character. "\s" plus the vertical tab ("\cK").
+ upper Any uppercase character ("[A-Z]").
+ word A Perl extension ("[A-Za-z0-9_]"), equivalent to "\w".
+ xdigit Any hexadecimal digit ("[0-9a-fA-F]").
+
+Most POSIX character classes have two Unicode-style C<\p> property
+counterparts. (They are not official Unicode properties, but Perl extensions
+derived from official Unicode properties.) The table below shows the relation
+between POSIX character classes and these counterparts.
+
+One counterpart, in the column labelled "ASCII-range Unicode" in
+the table, will only match characters in the ASCII character set.
+
+The other counterpart, in the column labelled "Full-range Unicode", matches any
+appropriate characters in the full Unicode character set. For example,
+C<\p{Alpha}> will match not just the ASCII alphabetic characters, but any
+character in the entire Unicode character set that is considered to be
+alphabetic.
+
+(Each of the counterparts has various synonyms as well.
+L<perluniprops/Properties accessible through \p{} and \P{}> lists all the
+synonyms, plus all the characters matched by each of the ASCII-range
+properties. For example C<\p{AHex}> is a synonym for C<\p{ASCII_Hex_Digit}>,
+and any C<\p> property name can be prefixed with "Is" such as C<\p{IsAlpha}>.)
+
+Both the C<\p> forms are unaffected by any locale that is in effect, or whether
+the string is in UTF-8 format or not, or whether the platform is EBCDIC or not.
+In contrast, the POSIX character classes are affected. If the source string is
+in UTF-8 format, the POSIX classes (with the exception of C<[[:punct:]]>, see
+Note [5] below) behave like their "Full-range" Unicode counterparts. If the
+source string is not in UTF-8 format, and no locale is in effect, and the
+platform is not EBCDIC, all the POSIX classes behave like their ASCII-range
+counterparts. Otherwise, they behave based on the rules of the locale or
+EBCDIC code page.
+
+It is proposed to change this behavior in a future release of Perl so that the
+the UTF8ness of the source string will be irrelevant to the behavior of the
+POSIX character classes. This means they will always behave in strict
+accordance with the official POSIX standard. That is, if either locale or
+EBCDIC code page is present, they will behave in accordance with those; if
+absent, the classes will match only their ASCII-range counterparts. If you
+disagree with this proposal, send email to C<perl5-porters@perl.org>.
+
+ [[:...:]] ASCII-range Full-range backslash Note
+ Unicode Unicode sequence
+ -----------------------------------------------------
+ alpha \p{PosixAlpha} \p{Alpha}
+ alnum \p{PosixAlnum} \p{Alnum}
+ ascii \p{ASCII}
+ blank \p{PosixBlank} \p{Blank} = [1]
+ \p{HorizSpace} \h [1]
+ cntrl \p{PosixCntrl} \p{Cntrl} [2]
+ digit \p{PosixDigit} \p{Digit} \d
+ graph \p{PosixGraph} \p{Graph} [3]
+ lower \p{PosixLower} \p{Lower}
+ print \p{PosixPrint} \p{Print} [4]
+ punct \p{PosixPunct} \p{Punct} [5]
+ \p{PerlSpace} \p{SpacePerl} \s [6]
+ space \p{PosixSpace} \p{Space} [6]
+ upper \p{PosixUpper} \p{Upper}
+ word \p{PerlWord} \p{Word} \w
+ xdigit \p{ASCII_Hex_Digit} \p{XDigit}
+
+=over 4
+
+=item [1]
+
+C<\p{Blank}> and C<\p{HorizSpace}> are synonyms.
+
+=item [2]
+
+Control characters don't produce output as such, but instead usually control
+the terminal somehow: for example newline and backspace are control characters.
+In the ASCII range, characters whose ordinals are between 0 and 31 inclusive,
+plus 127 (C<DEL>) are control characters.
+
+On EBCDIC platforms, it is likely that the code page will define C<[[:cntrl:]]>
+to be the EBCDIC equivalents of the ASCII controls, plus the controls
+that in Unicode have ordinals from 128 through 159.
+
+=item [3]
+
+Any character that is I<graphical>, that is, visible. This class consists
+of all the alphanumerical characters and all punctuation characters.
+
+=item [4]
+
+All printable characters, which is the set of all the graphical characters
+plus whitespace characters that are not also controls.
+
+=item [5] (punct)
+
+C<\p{PosixPunct}> and C<[[:punct:]]> in the ASCII range match all the
+non-controls, non-alphanumeric, non-space characters:
+C<[-!"#$%&'()*+,./:;<=E<gt>?@[\\\]^_`{|}~]> (although if a locale is in effect,
+it could alter the behavior of C<[[:punct:]]>).
+
+C<\p{Punct}> matches a somewhat different set in the ASCII range, namely
+C<[-!"#%&'()*,./:;?@[\\\]_{}]>. That is, it is missing C<[$+E<lt>=E<gt>^`|~]>.
+This is because Unicode splits what POSIX considers to be punctuation into two
+categories, Punctuation and Symbols.
+
+When the matching string is in UTF-8 format, C<[[:punct:]]> matches what it
+matches in the ASCII range, plus what C<\p{Punct}> matches. This is different
+than strictly matching according to C<\p{Punct}>. Another way to say it is that
+for a UTF-8 string, C<[[:punct:]]> matches all the characters that Unicode
+considers to be punctuation, plus all the ASCII-range characters that Unicode
+considers to be symbols.
+
+=item [6]
+
+C<\p{SpacePerl}> and C<\p{Space}> differ only in that C<\p{Space}> additionally
+matches the vertical tab, C<\cK>. Same for the two ASCII-only range forms.
+
+=back
+
+=head4 Negation
+X<character class, negation>
+
+A Perl extension to the POSIX character class is the ability to
+negate it. This is done by prefixing the class name with a caret (C<^>).
+Some examples:
+
+ POSIX ASCII-range Full-range backslash
+ Unicode Unicode sequence
+ -----------------------------------------------------
+ [[:^digit:]] \P{PosixDigit} \P{Digit} \D
+ [[:^space:]] \P{PosixSpace} \P{Space}
+ \P{PerlSpace} \P{SpacePerl} \S
+ [[:^word:]] \P{PerlWord} \P{Word} \W
+
+=head4 [= =] and [. .]
+
+Perl will recognize the POSIX character classes C<[=class=]>, and
+C<[.class.]>, but does not (yet?) support them. Use of
+such a construct will lead to an error.
+
+
+=head4 Examples
+
+ /[[:digit:]]/ # Matches a character that is a digit.
+ /[01[:lower:]]/ # Matches a character that is either a
+ # lowercase letter, or '0' or '1'.
+ /[[:digit:][:^xdigit:]]/ # Matches a character that can be anything
+ # except the letters 'a' to 'f'. This is
+ # because the main character class is composed
+ # of two POSIX character classes that are ORed
+ # together, one that matches any digit, and
+ # the other that matches anything that isn't a
+ # hex digit. The result matches all
+ # characters except the letters 'a' to 'f' and
+ # 'A' to 'F'.
+
+
+=head2 Locale, EBCDIC, Unicode and UTF-8
+
+Some of the character classes have a somewhat different behaviour depending
+on the internal encoding of the source string, and the locale that is
+in effect, and if the program is running on an EBCDIC platform.
+
+C<\w>, C<\d>, C<\s> and the POSIX character classes (and their negations,
+including C<\W>, C<\D>, C<\S>) suffer from this behaviour. (Since the backslash
+sequences C<\b> and C<\B> are defined in terms of C<\w> and C<\W>, they also are
+affected.)
+
+The rule is that if the source string is in UTF-8 format, the character
+classes match according to the Unicode properties. If the source string
+isn't, then the character classes match according to whatever locale or EBCDIC
+code page is in effect. If there is no locale nor EBCDIC, they match the ASCII
+defaults (0 to 9 for C<\d>; 52 letters, 10 digits and underscore for C<\w>;
+etc.).
+
+This usually means that if you are matching against characters whose C<ord()>
+values are between 128 and 255 inclusive, your character class may match
+or not depending on the current locale or EBCDIC code page, and whether the
+source string is in UTF-8 format. The string will be in UTF-8 format if it
+contains characters whose C<ord()> value exceeds 255. But a string may be in
+UTF-8 format without it having such characters. See L<perlunicode/The
+"Unicode Bug">.
+
+For portability reasons, it may be better to not use C<\w>, C<\d>, C<\s>
+or the POSIX character classes, and use the Unicode properties instead.
+
+=head4 Examples
+
+ $str = "\xDF"; # $str is not in UTF-8 format.
+ $str =~ /^\w/; # No match, as $str isn't in UTF-8 format.
+ $str .= "\x{0e0b}"; # Now $str is in UTF-8 format.
+ $str =~ /^\w/; # Match! $str is now in UTF-8 format.
+ chop $str;
+ $str =~ /^\w/; # Still a match! $str remains in UTF-8 format.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlref.pod b/Master/tlpkg/tlperl/lib/pods/perlref.pod
new file mode 100644
index 00000000000..550f4c14d21
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlref.pod
@@ -0,0 +1,686 @@
+=head1 NAME
+X<reference> X<pointer> X<data structure> X<structure> X<struct>
+
+perlref - Perl references and nested data structures
+
+=head1 NOTE
+
+This is complete documentation about all aspects of references.
+For a shorter, tutorial introduction to just the essential features,
+see L<perlreftut>.
+
+=head1 DESCRIPTION
+
+Before release 5 of Perl it was difficult to represent complex data
+structures, because all references had to be symbolic--and even then
+it was difficult to refer to a variable instead of a symbol table entry.
+Perl now not only makes it easier to use symbolic references to variables,
+but also lets you have "hard" references to any piece of data or code.
+Any scalar may hold a hard reference. Because arrays and hashes contain
+scalars, you can now easily build arrays of arrays, arrays of hashes,
+hashes of arrays, arrays of hashes of functions, and so on.
+
+Hard references are smart--they keep track of reference counts for you,
+automatically freeing the thing referred to when its reference count goes
+to zero. (Reference counts for values in self-referential or
+cyclic data structures may not go to zero without a little help; see
+L<perlobj/"Two-Phased Garbage Collection"> for a detailed explanation.)
+If that thing happens to be an object, the object is destructed. See
+L<perlobj> for more about objects. (In a sense, everything in Perl is an
+object, but we usually reserve the word for references to objects that
+have been officially "blessed" into a class package.)
+
+Symbolic references are names of variables or other objects, just as a
+symbolic link in a Unix filesystem contains merely the name of a file.
+The C<*glob> notation is something of a symbolic reference. (Symbolic
+references are sometimes called "soft references", but please don't call
+them that; references are confusing enough without useless synonyms.)
+X<reference, symbolic> X<reference, soft>
+X<symbolic reference> X<soft reference>
+
+In contrast, hard references are more like hard links in a Unix file
+system: They are used to access an underlying object without concern for
+what its (other) name is. When the word "reference" is used without an
+adjective, as in the following paragraph, it is usually talking about a
+hard reference.
+X<reference, hard> X<hard reference>
+
+References are easy to use in Perl. There is just one overriding
+principle: Perl does no implicit referencing or dereferencing. When a
+scalar is holding a reference, it always behaves as a simple scalar. It
+doesn't magically start being an array or hash or subroutine; you have to
+tell it explicitly to do so, by dereferencing it.
+
+=head2 Making References
+X<reference, creation> X<referencing>
+
+References can be created in several ways.
+
+=over 4
+
+=item 1.
+X<\> X<backslash>
+
+By using the backslash operator on a variable, subroutine, or value.
+(This works much like the & (address-of) operator in C.)
+This typically creates I<another> reference to a variable, because
+there's already a reference to the variable in the symbol table. But
+the symbol table reference might go away, and you'll still have the
+reference that the backslash returned. Here are some examples:
+
+ $scalarref = \$foo;
+ $arrayref = \@ARGV;
+ $hashref = \%ENV;
+ $coderef = \&handler;
+ $globref = \*foo;
+
+It isn't possible to create a true reference to an IO handle (filehandle
+or dirhandle) using the backslash operator. The most you can get is a
+reference to a typeglob, which is actually a complete symbol table entry.
+But see the explanation of the C<*foo{THING}> syntax below. However,
+you can still use type globs and globrefs as though they were IO handles.
+
+=item 2.
+X<array, anonymous> X<[> X<[]> X<square bracket>
+X<bracket, square> X<arrayref> X<array reference> X<reference, array>
+
+A reference to an anonymous array can be created using square
+brackets:
+
+ $arrayref = [1, 2, ['a', 'b', 'c']];
+
+Here we've created a reference to an anonymous array of three elements
+whose final element is itself a reference to another anonymous array of three
+elements. (The multidimensional syntax described later can be used to
+access this. For example, after the above, C<< $arrayref->[2][1] >> would have
+the value "b".)
+
+Taking a reference to an enumerated list is not the same
+as using square brackets--instead it's the same as creating
+a list of references!
+
+ @list = (\$a, \@b, \%c);
+ @list = \($a, @b, %c); # same thing!
+
+As a special case, C<\(@foo)> returns a list of references to the contents
+of C<@foo>, not a reference to C<@foo> itself. Likewise for C<%foo>,
+except that the key references are to copies (since the keys are just
+strings rather than full-fledged scalars).
+
+=item 3.
+X<hash, anonymous> X<{> X<{}> X<curly bracket>
+X<bracket, curly> X<brace> X<hashref> X<hash reference> X<reference, hash>
+
+A reference to an anonymous hash can be created using curly
+brackets:
+
+ $hashref = {
+ 'Adam' => 'Eve',
+ 'Clyde' => 'Bonnie',
+ };
+
+Anonymous hash and array composers like these can be intermixed freely to
+produce as complicated a structure as you want. The multidimensional
+syntax described below works for these too. The values above are
+literals, but variables and expressions would work just as well, because
+assignment operators in Perl (even within local() or my()) are executable
+statements, not compile-time declarations.
+
+Because curly brackets (braces) are used for several other things
+including BLOCKs, you may occasionally have to disambiguate braces at the
+beginning of a statement by putting a C<+> or a C<return> in front so
+that Perl realizes the opening brace isn't starting a BLOCK. The economy and
+mnemonic value of using curlies is deemed worth this occasional extra
+hassle.
+
+For example, if you wanted a function to make a new hash and return a
+reference to it, you have these options:
+
+ sub hashem { { @_ } } # silently wrong
+ sub hashem { +{ @_ } } # ok
+ sub hashem { return { @_ } } # ok
+
+On the other hand, if you want the other meaning, you can do this:
+
+ sub showem { { @_ } } # ambiguous (currently ok, but may change)
+ sub showem { {; @_ } } # ok
+ sub showem { { return @_ } } # ok
+
+The leading C<+{> and C<{;> always serve to disambiguate
+the expression to mean either the HASH reference, or the BLOCK.
+
+=item 4.
+X<subroutine, anonymous> X<subroutine, reference> X<reference, subroutine>
+X<scope, lexical> X<closure> X<lexical> X<lexical scope>
+
+A reference to an anonymous subroutine can be created by using
+C<sub> without a subname:
+
+ $coderef = sub { print "Boink!\n" };
+
+Note the semicolon. Except for the code
+inside not being immediately executed, a C<sub {}> is not so much a
+declaration as it is an operator, like C<do{}> or C<eval{}>. (However, no
+matter how many times you execute that particular line (unless you're in an
+C<eval("...")>), $coderef will still have a reference to the I<same>
+anonymous subroutine.)
+
+Anonymous subroutines act as closures with respect to my() variables,
+that is, variables lexically visible within the current scope. Closure
+is a notion out of the Lisp world that says if you define an anonymous
+function in a particular lexical context, it pretends to run in that
+context even when it's called outside the context.
+
+In human terms, it's a funny way of passing arguments to a subroutine when
+you define it as well as when you call it. It's useful for setting up
+little bits of code to run later, such as callbacks. You can even
+do object-oriented stuff with it, though Perl already provides a different
+mechanism to do that--see L<perlobj>.
+
+You might also think of closure as a way to write a subroutine
+template without using eval(). Here's a small example of how
+closures work:
+
+ sub newprint {
+ my $x = shift;
+ return sub { my $y = shift; print "$x, $y!\n"; };
+ }
+ $h = newprint("Howdy");
+ $g = newprint("Greetings");
+
+ # Time passes...
+
+ &$h("world");
+ &$g("earthlings");
+
+This prints
+
+ Howdy, world!
+ Greetings, earthlings!
+
+Note particularly that $x continues to refer to the value passed
+into newprint() I<despite> "my $x" having gone out of scope by the
+time the anonymous subroutine runs. That's what a closure is all
+about.
+
+This applies only to lexical variables, by the way. Dynamic variables
+continue to work as they have always worked. Closure is not something
+that most Perl programmers need trouble themselves about to begin with.
+
+=item 5.
+X<constructor> X<new>
+
+References are often returned by special subroutines called constructors. Perl
+objects are just references to a special type of object that happens to know
+which package it's associated with. Constructors are just special subroutines
+that know how to create that association. They do so by starting with an
+ordinary reference, and it remains an ordinary reference even while it's also
+being an object. Constructors are often named C<new()>. You I<can> call them
+indirectly:
+
+ $objref = new Doggie( Tail => 'short', Ears => 'long' );
+
+But that can produce ambiguous syntax in certain cases, so it's often
+better to use the direct method invocation approach:
+
+ $objref = Doggie->new(Tail => 'short', Ears => 'long');
+
+ use Term::Cap;
+ $terminal = Term::Cap->Tgetent( { OSPEED => 9600 });
+
+ use Tk;
+ $main = MainWindow->new();
+ $menubar = $main->Frame(-relief => "raised",
+ -borderwidth => 2)
+
+=item 6.
+X<autovivification>
+
+References of the appropriate type can spring into existence if you
+dereference them in a context that assumes they exist. Because we haven't
+talked about dereferencing yet, we can't show you any examples yet.
+
+=item 7.
+X<*foo{THING}> X<*>
+
+A reference can be created by using a special syntax, lovingly known as
+the *foo{THING} syntax. *foo{THING} returns a reference to the THING
+slot in *foo (which is the symbol table entry which holds everything
+known as foo).
+
+ $scalarref = *foo{SCALAR};
+ $arrayref = *ARGV{ARRAY};
+ $hashref = *ENV{HASH};
+ $coderef = *handler{CODE};
+ $ioref = *STDIN{IO};
+ $globref = *foo{GLOB};
+ $formatref = *foo{FORMAT};
+
+All of these are self-explanatory except for C<*foo{IO}>. It returns
+the IO handle, used for file handles (L<perlfunc/open>), sockets
+(L<perlfunc/socket> and L<perlfunc/socketpair>), and directory
+handles (L<perlfunc/opendir>). For compatibility with previous
+versions of Perl, C<*foo{FILEHANDLE}> is a synonym for C<*foo{IO}>, though it
+is deprecated as of 5.8.0. If deprecation warnings are in effect, it will warn
+of its use.
+
+C<*foo{THING}> returns undef if that particular THING hasn't been used yet,
+except in the case of scalars. C<*foo{SCALAR}> returns a reference to an
+anonymous scalar if $foo hasn't been used yet. This might change in a
+future release.
+
+C<*foo{IO}> is an alternative to the C<*HANDLE> mechanism given in
+L<perldata/"Typeglobs and Filehandles"> for passing filehandles
+into or out of subroutines, or storing into larger data structures.
+Its disadvantage is that it won't create a new filehandle for you.
+Its advantage is that you have less risk of clobbering more than
+you want to with a typeglob assignment. (It still conflates file
+and directory handles, though.) However, if you assign the incoming
+value to a scalar instead of a typeglob as we do in the examples
+below, there's no risk of that happening.
+
+ splutter(*STDOUT); # pass the whole glob
+ splutter(*STDOUT{IO}); # pass both file and dir handles
+
+ sub splutter {
+ my $fh = shift;
+ print $fh "her um well a hmmm\n";
+ }
+
+ $rec = get_rec(*STDIN); # pass the whole glob
+ $rec = get_rec(*STDIN{IO}); # pass both file and dir handles
+
+ sub get_rec {
+ my $fh = shift;
+ return scalar <$fh>;
+ }
+
+=back
+
+=head2 Using References
+X<reference, use> X<dereferencing> X<dereference>
+
+That's it for creating references. By now you're probably dying to
+know how to use references to get back to your long-lost data. There
+are several basic methods.
+
+=over 4
+
+=item 1.
+
+Anywhere you'd put an identifier (or chain of identifiers) as part
+of a variable or subroutine name, you can replace the identifier with
+a simple scalar variable containing a reference of the correct type:
+
+ $bar = $$scalarref;
+ push(@$arrayref, $filename);
+ $$arrayref[0] = "January";
+ $$hashref{"KEY"} = "VALUE";
+ &$coderef(1,2,3);
+ print $globref "output\n";
+
+It's important to understand that we are specifically I<not> dereferencing
+C<$arrayref[0]> or C<$hashref{"KEY"}> there. The dereference of the
+scalar variable happens I<before> it does any key lookups. Anything more
+complicated than a simple scalar variable must use methods 2 or 3 below.
+However, a "simple scalar" includes an identifier that itself uses method
+1 recursively. Therefore, the following prints "howdy".
+
+ $refrefref = \\\"howdy";
+ print $$$$refrefref;
+
+=item 2.
+
+Anywhere you'd put an identifier (or chain of identifiers) as part of a
+variable or subroutine name, you can replace the identifier with a
+BLOCK returning a reference of the correct type. In other words, the
+previous examples could be written like this:
+
+ $bar = ${$scalarref};
+ push(@{$arrayref}, $filename);
+ ${$arrayref}[0] = "January";
+ ${$hashref}{"KEY"} = "VALUE";
+ &{$coderef}(1,2,3);
+ $globref->print("output\n"); # iff IO::Handle is loaded
+
+Admittedly, it's a little silly to use the curlies in this case, but
+the BLOCK can contain any arbitrary expression, in particular,
+subscripted expressions:
+
+ &{ $dispatch{$index} }(1,2,3); # call correct routine
+
+Because of being able to omit the curlies for the simple case of C<$$x>,
+people often make the mistake of viewing the dereferencing symbols as
+proper operators, and wonder about their precedence. If they were,
+though, you could use parentheses instead of braces. That's not the case.
+Consider the difference below; case 0 is a short-hand version of case 1,
+I<not> case 2:
+
+ $$hashref{"KEY"} = "VALUE"; # CASE 0
+ ${$hashref}{"KEY"} = "VALUE"; # CASE 1
+ ${$hashref{"KEY"}} = "VALUE"; # CASE 2
+ ${$hashref->{"KEY"}} = "VALUE"; # CASE 3
+
+Case 2 is also deceptive in that you're accessing a variable
+called %hashref, not dereferencing through $hashref to the hash
+it's presumably referencing. That would be case 3.
+
+=item 3.
+
+Subroutine calls and lookups of individual array elements arise often
+enough that it gets cumbersome to use method 2. As a form of
+syntactic sugar, the examples for method 2 may be written:
+
+ $arrayref->[0] = "January"; # Array element
+ $hashref->{"KEY"} = "VALUE"; # Hash element
+ $coderef->(1,2,3); # Subroutine call
+
+The left side of the arrow can be any expression returning a reference,
+including a previous dereference. Note that C<$array[$x]> is I<not> the
+same thing as C<< $array->[$x] >> here:
+
+ $array[$x]->{"foo"}->[0] = "January";
+
+This is one of the cases we mentioned earlier in which references could
+spring into existence when in an lvalue context. Before this
+statement, C<$array[$x]> may have been undefined. If so, it's
+automatically defined with a hash reference so that we can look up
+C<{"foo"}> in it. Likewise C<< $array[$x]->{"foo"} >> will automatically get
+defined with an array reference so that we can look up C<[0]> in it.
+This process is called I<autovivification>.
+
+One more thing here. The arrow is optional I<between> brackets
+subscripts, so you can shrink the above down to
+
+ $array[$x]{"foo"}[0] = "January";
+
+Which, in the degenerate case of using only ordinary arrays, gives you
+multidimensional arrays just like C's:
+
+ $score[$x][$y][$z] += 42;
+
+Well, okay, not entirely like C's arrays, actually. C doesn't know how
+to grow its arrays on demand. Perl does.
+
+=item 4.
+
+If a reference happens to be a reference to an object, then there are
+probably methods to access the things referred to, and you should probably
+stick to those methods unless you're in the class package that defines the
+object's methods. In other words, be nice, and don't violate the object's
+encapsulation without a very good reason. Perl does not enforce
+encapsulation. We are not totalitarians here. We do expect some basic
+civility though.
+
+=back
+
+Using a string or number as a reference produces a symbolic reference,
+as explained above. Using a reference as a number produces an
+integer representing its storage location in memory. The only
+useful thing to be done with this is to compare two references
+numerically to see whether they refer to the same location.
+X<reference, numeric context>
+
+ if ($ref1 == $ref2) { # cheap numeric compare of references
+ print "refs 1 and 2 refer to the same thing\n";
+ }
+
+Using a reference as a string produces both its referent's type,
+including any package blessing as described in L<perlobj>, as well
+as the numeric address expressed in hex. The ref() operator returns
+just the type of thing the reference is pointing to, without the
+address. See L<perlfunc/ref> for details and examples of its use.
+X<reference, string context>
+
+The bless() operator may be used to associate the object a reference
+points to with a package functioning as an object class. See L<perlobj>.
+
+A typeglob may be dereferenced the same way a reference can, because
+the dereference syntax always indicates the type of reference desired.
+So C<${*foo}> and C<${\$foo}> both indicate the same scalar variable.
+
+Here's a trick for interpolating a subroutine call into a string:
+
+ print "My sub returned @{[mysub(1,2,3)]} that time.\n";
+
+The way it works is that when the C<@{...}> is seen in the double-quoted
+string, it's evaluated as a block. The block creates a reference to an
+anonymous array containing the results of the call to C<mysub(1,2,3)>. So
+the whole block returns a reference to an array, which is then
+dereferenced by C<@{...}> and stuck into the double-quoted string. This
+chicanery is also useful for arbitrary expressions:
+
+ print "That yields @{[$n + 5]} widgets\n";
+
+Similarly, an expression that returns a reference to a scalar can be
+dereferenced via C<${...}>. Thus, the above expression may be written
+as:
+
+ print "That yields ${\($n + 5)} widgets\n";
+
+=head2 Symbolic references
+X<reference, symbolic> X<reference, soft>
+X<symbolic reference> X<soft reference>
+
+We said that references spring into existence as necessary if they are
+undefined, but we didn't say what happens if a value used as a
+reference is already defined, but I<isn't> a hard reference. If you
+use it as a reference, it'll be treated as a symbolic
+reference. That is, the value of the scalar is taken to be the I<name>
+of a variable, rather than a direct link to a (possibly) anonymous
+value.
+
+People frequently expect it to work like this. So it does.
+
+ $name = "foo";
+ $$name = 1; # Sets $foo
+ ${$name} = 2; # Sets $foo
+ ${$name x 2} = 3; # Sets $foofoo
+ $name->[0] = 4; # Sets $foo[0]
+ @$name = (); # Clears @foo
+ &$name(); # Calls &foo() (as in Perl 4)
+ $pack = "THAT";
+ ${"${pack}::$name"} = 5; # Sets $THAT::foo without eval
+
+This is powerful, and slightly dangerous, in that it's possible
+to intend (with the utmost sincerity) to use a hard reference, and
+accidentally use a symbolic reference instead. To protect against
+that, you can say
+
+ use strict 'refs';
+
+and then only hard references will be allowed for the rest of the enclosing
+block. An inner block may countermand that with
+
+ no strict 'refs';
+
+Only package variables (globals, even if localized) are visible to
+symbolic references. Lexical variables (declared with my()) aren't in
+a symbol table, and thus are invisible to this mechanism. For example:
+
+ local $value = 10;
+ $ref = "value";
+ {
+ my $value = 20;
+ print $$ref;
+ }
+
+This will still print 10, not 20. Remember that local() affects package
+variables, which are all "global" to the package.
+
+=head2 Not-so-symbolic references
+
+A new feature contributing to readability in perl version 5.001 is that the
+brackets around a symbolic reference behave more like quotes, just as they
+always have within a string. That is,
+
+ $push = "pop on ";
+ print "${push}over";
+
+has always meant to print "pop on over", even though push is
+a reserved word. This has been generalized to work the same outside
+of quotes, so that
+
+ print ${push} . "over";
+
+and even
+
+ print ${ push } . "over";
+
+will have the same effect. (This would have been a syntax error in
+Perl 5.000, though Perl 4 allowed it in the spaceless form.) This
+construct is I<not> considered to be a symbolic reference when you're
+using strict refs:
+
+ use strict 'refs';
+ ${ bareword }; # Okay, means $bareword.
+ ${ "bareword" }; # Error, symbolic reference.
+
+Similarly, because of all the subscripting that is done using single
+words, we've applied the same rule to any bareword that is used for
+subscripting a hash. So now, instead of writing
+
+ $array{ "aaa" }{ "bbb" }{ "ccc" }
+
+you can write just
+
+ $array{ aaa }{ bbb }{ ccc }
+
+and not worry about whether the subscripts are reserved words. In the
+rare event that you do wish to do something like
+
+ $array{ shift }
+
+you can force interpretation as a reserved word by adding anything that
+makes it more than a bareword:
+
+ $array{ shift() }
+ $array{ +shift }
+ $array{ shift @_ }
+
+The C<use warnings> pragma or the B<-w> switch will warn you if it
+interprets a reserved word as a string.
+But it will no longer warn you about using lowercase words, because the
+string is effectively quoted.
+
+=head2 Pseudo-hashes: Using an array as a hash
+X<pseudo-hash> X<pseudo hash> X<pseudohash>
+
+Pseudo-hashes have been removed from Perl. The 'fields' pragma
+remains available.
+
+=head2 Function Templates
+X<scope, lexical> X<closure> X<lexical> X<lexical scope>
+X<subroutine, nested> X<sub, nested> X<subroutine, local> X<sub, local>
+
+As explained above, an anonymous function with access to the lexical
+variables visible when that function was compiled, creates a closure. It
+retains access to those variables even though it doesn't get run until
+later, such as in a signal handler or a Tk callback.
+
+Using a closure as a function template allows us to generate many functions
+that act similarly. Suppose you wanted functions named after the colors
+that generated HTML font changes for the various colors:
+
+ print "Be ", red("careful"), "with that ", green("light");
+
+The red() and green() functions would be similar. To create these,
+we'll assign a closure to a typeglob of the name of the function we're
+trying to build.
+
+ @colors = qw(red blue green yellow orange purple violet);
+ for my $name (@colors) {
+ no strict 'refs'; # allow symbol table manipulation
+ *$name = *{uc $name} = sub { "<FONT COLOR='$name'>@_</FONT>" };
+ }
+
+Now all those different functions appear to exist independently. You can
+call red(), RED(), blue(), BLUE(), green(), etc. This technique saves on
+both compile time and memory use, and is less error-prone as well, since
+syntax checks happen at compile time. It's critical that any variables in
+the anonymous subroutine be lexicals in order to create a proper closure.
+That's the reasons for the C<my> on the loop iteration variable.
+
+This is one of the only places where giving a prototype to a closure makes
+much sense. If you wanted to impose scalar context on the arguments of
+these functions (probably not a wise idea for this particular example),
+you could have written it this way instead:
+
+ *$name = sub ($) { "<FONT COLOR='$name'>$_[0]</FONT>" };
+
+However, since prototype checking happens at compile time, the assignment
+above happens too late to be of much use. You could address this by
+putting the whole loop of assignments within a BEGIN block, forcing it
+to occur during compilation.
+
+Access to lexicals that change over time--like those in the C<for> loop
+above, basically aliases to elements from the surrounding lexical scopes--
+only works with anonymous subs, not with named subroutines. Generally
+said, named subroutines do not nest properly and should only be declared
+in the main package scope.
+
+This is because named subroutines are created at compile time so their
+lexical variables get assigned to the parent lexicals from the first
+execution of the parent block. If a parent scope is entered a second
+time, its lexicals are created again, while the nested subs still
+reference the old ones.
+
+Anonymous subroutines get to capture each time you execute the C<sub>
+operator, as they are created on the fly. If you are accustomed to using
+nested subroutines in other programming languages with their own private
+variables, you'll have to work at it a bit in Perl. The intuitive coding
+of this type of thing incurs mysterious warnings about "will not stay
+shared" due to the reasons explained above.
+For example, this won't work:
+
+ sub outer {
+ my $x = $_[0] + 35;
+ sub inner { return $x * 19 } # WRONG
+ return $x + inner();
+ }
+
+A work-around is the following:
+
+ sub outer {
+ my $x = $_[0] + 35;
+ local *inner = sub { return $x * 19 };
+ return $x + inner();
+ }
+
+Now inner() can only be called from within outer(), because of the
+temporary assignments of the anonymous subroutine. But when it does,
+it has normal access to the lexical variable $x from the scope of
+outer() at the time outer is invoked.
+
+This has the interesting effect of creating a function local to another
+function, something not normally supported in Perl.
+
+=head1 WARNING
+X<reference, string context> X<reference, use as hash key>
+
+You may not (usefully) use a reference as the key to a hash. It will be
+converted into a string:
+
+ $x{ \$a } = $a;
+
+If you try to dereference the key, it won't do a hard dereference, and
+you won't accomplish what you're attempting. You might want to do something
+more like
+
+ $r = \@a;
+ $x{ $r } = $r;
+
+And then at least you can use the values(), which will be
+real refs, instead of the keys(), which won't.
+
+The standard Tie::RefHash module provides a convenient workaround to this.
+
+=head1 SEE ALSO
+
+Besides the obvious documents, source code can be instructive.
+Some pathological examples of the use of references can be found
+in the F<t/op/ref.t> regression test in the Perl source directory.
+
+See also L<perldsc> and L<perllol> for how to use references to create
+complex data structures, and L<perltoot>, L<perlobj>, and L<perlbot>
+for how to use them to create objects.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlreftut.pod b/Master/tlpkg/tlperl/lib/pods/perlreftut.pod
new file mode 100644
index 00000000000..7898b6db53c
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlreftut.pod
@@ -0,0 +1,527 @@
+=head1 NAME
+
+perlreftut - Mark's very short tutorial about references
+
+=head1 DESCRIPTION
+
+One of the most important new features in Perl 5 was the capability to
+manage complicated data structures like multidimensional arrays and
+nested hashes. To enable these, Perl 5 introduced a feature called
+`references', and using references is the key to managing complicated,
+structured data in Perl. Unfortunately, there's a lot of funny syntax
+to learn, and the main manual page can be hard to follow. The manual
+is quite complete, and sometimes people find that a problem, because
+it can be hard to tell what is important and what isn't.
+
+Fortunately, you only need to know 10% of what's in the main page to get
+90% of the benefit. This page will show you that 10%.
+
+=head1 Who Needs Complicated Data Structures?
+
+One problem that came up all the time in Perl 4 was how to represent a
+hash whose values were lists. Perl 4 had hashes, of course, but the
+values had to be scalars; they couldn't be lists.
+
+Why would you want a hash of lists? Let's take a simple example: You
+have a file of city and country names, like this:
+
+ Chicago, USA
+ Frankfurt, Germany
+ Berlin, Germany
+ Washington, USA
+ Helsinki, Finland
+ New York, USA
+
+and you want to produce an output like this, with each country mentioned
+once, and then an alphabetical list of the cities in that country:
+
+ Finland: Helsinki.
+ Germany: Berlin, Frankfurt.
+ USA: Chicago, New York, Washington.
+
+The natural way to do this is to have a hash whose keys are country
+names. Associated with each country name key is a list of the cities in
+that country. Each time you read a line of input, split it into a country
+and a city, look up the list of cities already known to be in that
+country, and append the new city to the list. When you're done reading
+the input, iterate over the hash as usual, sorting each list of cities
+before you print it out.
+
+If hash values can't be lists, you lose. In Perl 4, hash values can't
+be lists; they can only be strings. You lose. You'd probably have to
+combine all the cities into a single string somehow, and then when
+time came to write the output, you'd have to break the string into a
+list, sort the list, and turn it back into a string. This is messy
+and error-prone. And it's frustrating, because Perl already has
+perfectly good lists that would solve the problem if only you could
+use them.
+
+=head1 The Solution
+
+By the time Perl 5 rolled around, we were already stuck with this
+design: Hash values must be scalars. The solution to this is
+references.
+
+A reference is a scalar value that I<refers to> an entire array or an
+entire hash (or to just about anything else). Names are one kind of
+reference that you're already familiar with. Think of the President
+of the United States: a messy, inconvenient bag of blood and bones.
+But to talk about him, or to represent him in a computer program, all
+you need is the easy, convenient scalar string "Barack Obama".
+
+References in Perl are like names for arrays and hashes. They're
+Perl's private, internal names, so you can be sure they're
+unambiguous. Unlike "Barack Obama", a reference only refers to one
+thing, and you always know what it refers to. If you have a reference
+to an array, you can recover the entire array from it. If you have a
+reference to a hash, you can recover the entire hash. But the
+reference is still an easy, compact scalar value.
+
+You can't have a hash whose values are arrays; hash values can only be
+scalars. We're stuck with that. But a single reference can refer to
+an entire array, and references are scalars, so you can have a hash of
+references to arrays, and it'll act a lot like a hash of arrays, and
+it'll be just as useful as a hash of arrays.
+
+We'll come back to this city-country problem later, after we've seen
+some syntax for managing references.
+
+
+=head1 Syntax
+
+There are just two ways to make a reference, and just two ways to use
+it once you have it.
+
+=head2 Making References
+
+=head3 B<Make Rule 1>
+
+If you put a C<\> in front of a variable, you get a
+reference to that variable.
+
+ $aref = \@array; # $aref now holds a reference to @array
+ $href = \%hash; # $href now holds a reference to %hash
+ $sref = \$scalar; # $sref now holds a reference to $scalar
+
+Once the reference is stored in a variable like $aref or $href, you
+can copy it or store it just the same as any other scalar value:
+
+ $xy = $aref; # $xy now holds a reference to @array
+ $p[3] = $href; # $p[3] now holds a reference to %hash
+ $z = $p[3]; # $z now holds a reference to %hash
+
+
+These examples show how to make references to variables with names.
+Sometimes you want to make an array or a hash that doesn't have a
+name. This is analogous to the way you like to be able to use the
+string C<"\n"> or the number 80 without having to store it in a named
+variable first.
+
+B<Make Rule 2>
+
+C<[ ITEMS ]> makes a new, anonymous array, and returns a reference to
+that array. C<{ ITEMS }> makes a new, anonymous hash, and returns a
+reference to that hash.
+
+ $aref = [ 1, "foo", undef, 13 ];
+ # $aref now holds a reference to an array
+
+ $href = { APR => 4, AUG => 8 };
+ # $href now holds a reference to a hash
+
+
+The references you get from rule 2 are the same kind of
+references that you get from rule 1:
+
+ # This:
+ $aref = [ 1, 2, 3 ];
+
+ # Does the same as this:
+ @array = (1, 2, 3);
+ $aref = \@array;
+
+
+The first line is an abbreviation for the following two lines, except
+that it doesn't create the superfluous array variable C<@array>.
+
+If you write just C<[]>, you get a new, empty anonymous array.
+If you write just C<{}>, you get a new, empty anonymous hash.
+
+
+=head2 Using References
+
+What can you do with a reference once you have it? It's a scalar
+value, and we've seen that you can store it as a scalar and get it back
+again just like any scalar. There are just two more ways to use it:
+
+=head3 B<Use Rule 1>
+
+You can always use an array reference, in curly braces, in place of
+the name of an array. For example, C<@{$aref}> instead of C<@array>.
+
+Here are some examples of that:
+
+Arrays:
+
+
+ @a @{$aref} An array
+ reverse @a reverse @{$aref} Reverse the array
+ $a[3] ${$aref}[3] An element of the array
+ $a[3] = 17; ${$aref}[3] = 17 Assigning an element
+
+
+On each line are two expressions that do the same thing. The
+left-hand versions operate on the array C<@a>. The right-hand
+versions operate on the array that is referred to by C<$aref>. Once
+they find the array they're operating on, both versions do the same
+things to the arrays.
+
+Using a hash reference is I<exactly> the same:
+
+ %h %{$href} A hash
+ keys %h keys %{$href} Get the keys from the hash
+ $h{'red'} ${$href}{'red'} An element of the hash
+ $h{'red'} = 17 ${$href}{'red'} = 17 Assigning an element
+
+Whatever you want to do with a reference, B<Use Rule 1> tells you how
+to do it. You just write the Perl code that you would have written
+for doing the same thing to a regular array or hash, and then replace
+the array or hash name with C<{$reference}>. "How do I loop over an
+array when all I have is a reference?" Well, to loop over an array, you
+would write
+
+ for my $element (@array) {
+ ...
+ }
+
+so replace the array name, C<@array>, with the reference:
+
+ for my $element (@{$aref}) {
+ ...
+ }
+
+"How do I print out the contents of a hash when all I have is a
+reference?" First write the code for printing out a hash:
+
+ for my $key (keys %hash) {
+ print "$key => $hash{$key}\n";
+ }
+
+And then replace the hash name with the reference:
+
+ for my $key (keys %{$href}) {
+ print "$key => ${$href}{$key}\n";
+ }
+
+=head3 B<Use Rule 2>
+
+B<Use Rule 1> is all you really need, because it tells you how to do
+absolutely everything you ever need to do with references. But the
+most common thing to do with an array or a hash is to extract a single
+element, and the B<Use Rule 1> notation is cumbersome. So there is an
+abbreviation.
+
+C<${$aref}[3]> is too hard to read, so you can write C<< $aref->[3] >>
+instead.
+
+C<${$href}{red}> is too hard to read, so you can write
+C<< $href->{red} >> instead.
+
+If C<$aref> holds a reference to an array, then C<< $aref->[3] >> is
+the fourth element of the array. Don't confuse this with C<$aref[3]>,
+which is the fourth element of a totally different array, one
+deceptively named C<@aref>. C<$aref> and C<@aref> are unrelated the
+same way that C<$item> and C<@item> are.
+
+Similarly, C<< $href->{'red'} >> is part of the hash referred to by
+the scalar variable C<$href>, perhaps even one with no name.
+C<$href{'red'}> is part of the deceptively named C<%href> hash. It's
+easy to forget to leave out the C<< -> >>, and if you do, you'll get
+bizarre results when your program gets array and hash elements out of
+totally unexpected hashes and arrays that weren't the ones you wanted
+to use.
+
+
+=head2 An Example
+
+Let's see a quick example of how all this is useful.
+
+First, remember that C<[1, 2, 3]> makes an anonymous array containing
+C<(1, 2, 3)>, and gives you a reference to that array.
+
+Now think about
+
+ @a = ( [1, 2, 3],
+ [4, 5, 6],
+ [7, 8, 9]
+ );
+
+@a is an array with three elements, and each one is a reference to
+another array.
+
+C<$a[1]> is one of these references. It refers to an array, the array
+containing C<(4, 5, 6)>, and because it is a reference to an array,
+B<Use Rule 2> says that we can write C<< $a[1]->[2] >> to get the
+third element from that array. C<< $a[1]->[2] >> is the 6.
+Similarly, C<< $a[0]->[1] >> is the 2. What we have here is like a
+two-dimensional array; you can write C<< $a[ROW]->[COLUMN] >> to get
+or set the element in any row and any column of the array.
+
+The notation still looks a little cumbersome, so there's one more
+abbreviation:
+
+=head2 Arrow Rule
+
+In between two B<subscripts>, the arrow is optional.
+
+Instead of C<< $a[1]->[2] >>, we can write C<$a[1][2]>; it means the
+same thing. Instead of C<< $a[0]->[1] = 23 >>, we can write
+C<$a[0][1] = 23>; it means the same thing.
+
+Now it really looks like two-dimensional arrays!
+
+You can see why the arrows are important. Without them, we would have
+had to write C<${$a[1]}[2]> instead of C<$a[1][2]>. For
+three-dimensional arrays, they let us write C<$x[2][3][5]> instead of
+the unreadable C<${${$x[2]}[3]}[5]>.
+
+=head1 Solution
+
+Here's the answer to the problem I posed earlier, of reformatting a
+file of city and country names.
+
+ 1 my %table;
+
+ 2 while (<>) {
+ 3 chomp;
+ 4 my ($city, $country) = split /, /;
+ 5 $table{$country} = [] unless exists $table{$country};
+ 6 push @{$table{$country}}, $city;
+ 7 }
+
+ 8 foreach $country (sort keys %table) {
+ 9 print "$country: ";
+ 10 my @cities = @{$table{$country}};
+ 11 print join ', ', sort @cities;
+ 12 print ".\n";
+ 13 }
+
+
+The program has two pieces: Lines 2--7 read the input and build a data
+structure, and lines 8-13 analyze the data and print out the report.
+We're going to have a hash, C<%table>, whose keys are country names,
+and whose values are references to arrays of city names. The data
+structure will look like this:
+
+
+ %table
+ +-------+---+
+ | | | +-----------+--------+
+ |Germany| *---->| Frankfurt | Berlin |
+ | | | +-----------+--------+
+ +-------+---+
+ | | | +----------+
+ |Finland| *---->| Helsinki |
+ | | | +----------+
+ +-------+---+
+ | | | +---------+------------+----------+
+ | USA | *---->| Chicago | Washington | New York |
+ | | | +---------+------------+----------+
+ +-------+---+
+
+We'll look at output first. Supposing we already have this structure,
+how do we print it out?
+
+ 8 foreach $country (sort keys %table) {
+ 9 print "$country: ";
+ 10 my @cities = @{$table{$country}};
+ 11 print join ', ', sort @cities;
+ 12 print ".\n";
+ 13 }
+
+C<%table> is an
+ordinary hash, and we get a list of keys from it, sort the keys, and
+loop over the keys as usual. The only use of references is in line 10.
+C<$table{$country}> looks up the key C<$country> in the hash
+and gets the value, which is a reference to an array of cities in that country.
+B<Use Rule 1> says that
+we can recover the array by saying
+C<@{$table{$country}}>. Line 10 is just like
+
+ @cities = @array;
+
+except that the name C<array> has been replaced by the reference
+C<{$table{$country}}>. The C<@> tells Perl to get the entire array.
+Having gotten the list of cities, we sort it, join it, and print it
+out as usual.
+
+Lines 2-7 are responsible for building the structure in the first
+place. Here they are again:
+
+ 2 while (<>) {
+ 3 chomp;
+ 4 my ($city, $country) = split /, /;
+ 5 $table{$country} = [] unless exists $table{$country};
+ 6 push @{$table{$country}}, $city;
+ 7 }
+
+Lines 2-4 acquire a city and country name. Line 5 looks to see if the
+country is already present as a key in the hash. If it's not, the
+program uses the C<[]> notation (B<Make Rule 2>) to manufacture a new,
+empty anonymous array of cities, and installs a reference to it into
+the hash under the appropriate key.
+
+Line 6 installs the city name into the appropriate array.
+C<$table{$country}> now holds a reference to the array of cities seen
+in that country so far. Line 6 is exactly like
+
+ push @array, $city;
+
+except that the name C<array> has been replaced by the reference
+C<{$table{$country}}>. The C<push> adds a city name to the end of the
+referred-to array.
+
+There's one fine point I skipped. Line 5 is unnecessary, and we can
+get rid of it.
+
+ 2 while (<>) {
+ 3 chomp;
+ 4 my ($city, $country) = split /, /;
+ 5 #### $table{$country} = [] unless exists $table{$country};
+ 6 push @{$table{$country}}, $city;
+ 7 }
+
+If there's already an entry in C<%table> for the current C<$country>,
+then nothing is different. Line 6 will locate the value in
+C<$table{$country}>, which is a reference to an array, and push
+C<$city> into the array. But
+what does it do when
+C<$country> holds a key, say C<Greece>, that is not yet in C<%table>?
+
+This is Perl, so it does the exact right thing. It sees that you want
+to push C<Athens> onto an array that doesn't exist, so it helpfully
+makes a new, empty, anonymous array for you, installs it into
+C<%table>, and then pushes C<Athens> onto it. This is called
+`autovivification'--bringing things to life automatically. Perl saw
+that they key wasn't in the hash, so it created a new hash entry
+automatically. Perl saw that you wanted to use the hash value as an
+array, so it created a new empty array and installed a reference to it
+in the hash automatically. And as usual, Perl made the array one
+element longer to hold the new city name.
+
+=head1 The Rest
+
+I promised to give you 90% of the benefit with 10% of the details, and
+that means I left out 90% of the details. Now that you have an
+overview of the important parts, it should be easier to read the
+L<perlref> manual page, which discusses 100% of the details.
+
+Some of the highlights of L<perlref>:
+
+=over 4
+
+=item *
+
+You can make references to anything, including scalars, functions, and
+other references.
+
+=item *
+
+In B<Use Rule 1>, you can omit the curly brackets whenever the thing
+inside them is an atomic scalar variable like C<$aref>. For example,
+C<@$aref> is the same as C<@{$aref}>, and C<$$aref[1]> is the same as
+C<${$aref}[1]>. If you're just starting out, you may want to adopt
+the habit of always including the curly brackets.
+
+=item *
+
+This doesn't copy the underlying array:
+
+ $aref2 = $aref1;
+
+You get two references to the same array. If you modify
+C<< $aref1->[23] >> and then look at
+C<< $aref2->[23] >> you'll see the change.
+
+To copy the array, use
+
+ $aref2 = [@{$aref1}];
+
+This uses C<[...]> notation to create a new anonymous array, and
+C<$aref2> is assigned a reference to the new array. The new array is
+initialized with the contents of the array referred to by C<$aref1>.
+
+Similarly, to copy an anonymous hash, you can use
+
+ $href2 = {%{$href1}};
+
+=item *
+
+To see if a variable contains a reference, use the C<ref> function. It
+returns true if its argument is a reference. Actually it's a little
+better than that: It returns C<HASH> for hash references and C<ARRAY>
+for array references.
+
+=item *
+
+If you try to use a reference like a string, you get strings like
+
+ ARRAY(0x80f5dec) or HASH(0x826afc0)
+
+If you ever see a string that looks like this, you'll know you
+printed out a reference by mistake.
+
+A side effect of this representation is that you can use C<eq> to see
+if two references refer to the same thing. (But you should usually use
+C<==> instead because it's much faster.)
+
+=item *
+
+You can use a string as if it were a reference. If you use the string
+C<"foo"> as an array reference, it's taken to be a reference to the
+array C<@foo>. This is called a I<soft reference> or I<symbolic
+reference>. The declaration C<use strict 'refs'> disables this
+feature, which can cause all sorts of trouble if you use it by accident.
+
+=back
+
+You might prefer to go on to L<perllol> instead of L<perlref>; it
+discusses lists of lists and multidimensional arrays in detail. After
+that, you should move on to L<perldsc>; it's a Data Structure Cookbook
+that shows recipes for using and printing out arrays of hashes, hashes
+of arrays, and other kinds of data.
+
+=head1 Summary
+
+Everyone needs compound data structures, and in Perl the way you get
+them is with references. There are four important rules for managing
+references: Two for making references and two for using them. Once
+you know these rules you can do most of the important things you need
+to do with references.
+
+=head1 Credits
+
+Author: Mark Jason Dominus, Plover Systems (C<mjd-perl-ref+@plover.com>)
+
+This article originally appeared in I<The Perl Journal>
+( http://www.tpj.com/ ) volume 3, #2. Reprinted with permission.
+
+The original title was I<Understand References Today>.
+
+=head2 Distribution Conditions
+
+Copyright 1998 The Perl Journal.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in these files are
+hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun or for profit
+as you see fit. A simple comment in the code giving credit would be
+courteous but is not required.
+
+
+
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlreguts.pod b/Master/tlpkg/tlperl/lib/pods/perlreguts.pod
new file mode 100644
index 00000000000..ec1c243f8a9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlreguts.pod
@@ -0,0 +1,886 @@
+=head1 NAME
+
+perlreguts - Description of the Perl regular expression engine.
+
+=head1 DESCRIPTION
+
+This document is an attempt to shine some light on the guts of the regex
+engine and how it works. The regex engine represents a significant chunk
+of the perl codebase, but is relatively poorly understood. This document
+is a meagre attempt at addressing this situation. It is derived from the
+author's experience, comments in the source code, other papers on the
+regex engine, feedback on the perl5-porters mail list, and no doubt other
+places as well.
+
+B<NOTICE!> It should be clearly understood that the behavior and
+structures discussed in this represents the state of the engine as the
+author understood it at the time of writing. It is B<NOT> an API
+definition, it is purely an internals guide for those who want to hack
+the regex engine, or understand how the regex engine works. Readers of
+this document are expected to understand perl's regex syntax and its
+usage in detail. If you want to learn about the basics of Perl's
+regular expressions, see L<perlre>. And if you want to replace the
+regex engine with your own, see L<perlreapi>.
+
+=head1 OVERVIEW
+
+=head2 A quick note on terms
+
+There is some debate as to whether to say "regexp" or "regex". In this
+document we will use the term "regex" unless there is a special reason
+not to, in which case we will explain why.
+
+When speaking about regexes we need to distinguish between their source
+code form and their internal form. In this document we will use the term
+"pattern" when we speak of their textual, source code form, and the term
+"program" when we speak of their internal representation. These
+correspond to the terms I<S-regex> and I<B-regex> that Mark Jason
+Dominus employs in his paper on "Rx" ([1] in L</REFERENCES>).
+
+=head2 What is a regular expression engine?
+
+A regular expression engine is a program that takes a set of constraints
+specified in a mini-language, and then applies those constraints to a
+target string, and determines whether or not the string satisfies the
+constraints. See L<perlre> for a full definition of the language.
+
+In less grandiose terms, the first part of the job is to turn a pattern into
+something the computer can efficiently use to find the matching point in
+the string, and the second part is performing the search itself.
+
+To do this we need to produce a program by parsing the text. We then
+need to execute the program to find the point in the string that
+matches. And we need to do the whole thing efficiently.
+
+=head2 Structure of a Regexp Program
+
+=head3 High Level
+
+Although it is a bit confusing and some people object to the terminology, it
+is worth taking a look at a comment that has
+been in F<regexp.h> for years:
+
+I<This is essentially a linear encoding of a nondeterministic
+finite-state machine (aka syntax charts or "railroad normal form" in
+parsing technology).>
+
+The term "railroad normal form" is a bit esoteric, with "syntax
+diagram/charts", or "railroad diagram/charts" being more common terms.
+Nevertheless it provides a useful mental image of a regex program: each
+node can be thought of as a unit of track, with a single entry and in
+most cases a single exit point (there are pieces of track that fork, but
+statistically not many), and the whole forms a layout with a
+single entry and single exit point. The matching process can be thought
+of as a car that moves along the track, with the particular route through
+the system being determined by the character read at each possible
+connector point. A car can fall off the track at any point but it may
+only proceed as long as it matches the track.
+
+Thus the pattern C</foo(?:\w+|\d+|\s+)bar/> can be thought of as the
+following chart:
+
+ [start]
+ |
+ <foo>
+ |
+ +-----+-----+
+ | | |
+ <\w+> <\d+> <\s+>
+ | | |
+ +-----+-----+
+ |
+ <bar>
+ |
+ [end]
+
+The truth of the matter is that perl's regular expressions these days are
+much more complex than this kind of structure, but visualising it this way
+can help when trying to get your bearings, and it matches the
+current implementation pretty closely.
+
+To be more precise, we will say that a regex program is an encoding
+of a graph. Each node in the graph corresponds to part of
+the original regex pattern, such as a literal string or a branch,
+and has a pointer to the nodes representing the next component
+to be matched. Since "node" and "opcode" already have other meanings in the
+perl source, we will call the nodes in a regex program "regops".
+
+The program is represented by an array of C<regnode> structures, one or
+more of which represent a single regop of the program. Struct
+C<regnode> is the smallest struct needed, and has a field structure which is
+shared with all the other larger structures.
+
+The "next" pointers of all regops except C<BRANCH> implement concatenation;
+a "next" pointer with a C<BRANCH> on both ends of it is connecting two
+alternatives. [Here we have one of the subtle syntax dependencies: an
+individual C<BRANCH> (as opposed to a collection of them) is never
+concatenated with anything because of operator precedence.]
+
+The operand of some types of regop is a literal string; for others,
+it is a regop leading into a sub-program. In particular, the operand
+of a C<BRANCH> node is the first regop of the branch.
+
+B<NOTE>: As the railroad metaphor suggests, this is B<not> a tree
+structure: the tail of the branch connects to the thing following the
+set of C<BRANCH>es. It is a like a single line of railway track that
+splits as it goes into a station or railway yard and rejoins as it comes
+out the other side.
+
+=head3 Regops
+
+The base structure of a regop is defined in F<regexp.h> as follows:
+
+ struct regnode {
+ U8 flags; /* Various purposes, sometimes overridden */
+ U8 type; /* Opcode value as specified by regnodes.h */
+ U16 next_off; /* Offset in size regnode */
+ };
+
+Other larger C<regnode>-like structures are defined in F<regcomp.h>. They
+are almost like subclasses in that they have the same fields as
+C<regnode>, with possibly additional fields following in
+the structure, and in some cases the specific meaning (and name)
+of some of base fields are overridden. The following is a more
+complete description.
+
+=over 4
+
+=item C<regnode_1>
+
+=item C<regnode_2>
+
+C<regnode_1> structures have the same header, followed by a single
+four-byte argument; C<regnode_2> structures contain two two-byte
+arguments instead:
+
+ regnode_1 U32 arg1;
+ regnode_2 U16 arg1; U16 arg2;
+
+=item C<regnode_string>
+
+C<regnode_string> structures, used for literal strings, follow the header
+with a one-byte length and then the string data. Strings are padded on
+the end with zero bytes so that the total length of the node is a
+multiple of four bytes:
+
+ regnode_string char string[1];
+ U8 str_len; /* overrides flags */
+
+=item C<regnode_charclass>
+
+Character classes are represented by C<regnode_charclass> structures,
+which have a four-byte argument and then a 32-byte (256-bit) bitmap
+indicating which characters are included in the class.
+
+ regnode_charclass U32 arg1;
+ char bitmap[ANYOF_BITMAP_SIZE];
+
+=item C<regnode_charclass_class>
+
+There is also a larger form of a char class structure used to represent
+POSIX char classes called C<regnode_charclass_class> which has an
+additional 4-byte (32-bit) bitmap indicating which POSIX char classes
+have been included.
+
+ regnode_charclass_class U32 arg1;
+ char bitmap[ANYOF_BITMAP_SIZE];
+ char classflags[ANYOF_CLASSBITMAP_SIZE];
+
+=back
+
+F<regnodes.h> defines an array called C<regarglen[]> which gives the size
+of each opcode in units of C<size regnode> (4-byte). A macro is used
+to calculate the size of an C<EXACT> node based on its C<str_len> field.
+
+The regops are defined in F<regnodes.h> which is generated from
+F<regcomp.sym> by F<regcomp.pl>. Currently the maximum possible number
+of distinct regops is restricted to 256, with about a quarter already
+used.
+
+A set of macros makes accessing the fields
+easier and more consistent. These include C<OP()>, which is used to determine
+the type of a C<regnode>-like structure; C<NEXT_OFF()>, which is the offset to
+the next node (more on this later); C<ARG()>, C<ARG1()>, C<ARG2()>, C<ARG_SET()>,
+and equivalents for reading and setting the arguments; and C<STR_LEN()>,
+C<STRING()> and C<OPERAND()> for manipulating strings and regop bearing
+types.
+
+=head3 What regop is next?
+
+There are three distinct concepts of "next" in the regex engine, and
+it is important to keep them clear.
+
+=over 4
+
+=item *
+
+There is the "next regnode" from a given regnode, a value which is
+rarely useful except that sometimes it matches up in terms of value
+with one of the others, and that sometimes the code assumes this to
+always be so.
+
+=item *
+
+There is the "next regop" from a given regop/regnode. This is the
+regop physically located after the current one, as determined by
+the size of the current regop. This is often useful, such as when
+dumping the structure we use this order to traverse. Sometimes the code
+assumes that the "next regnode" is the same as the "next regop", or in
+other words assumes that the sizeof a given regop type is always going
+to be one regnode large.
+
+=item *
+
+There is the "regnext" from a given regop. This is the regop which
+is reached by jumping forward by the value of C<NEXT_OFF()>,
+or in a few cases for longer jumps by the C<arg1> field of the C<regnode_1>
+structure. The subroutine C<regnext()> handles this transparently.
+This is the logical successor of the node, which in some cases, like
+that of the C<BRANCH> regop, has special meaning.
+
+=back
+
+=head1 Process Overview
+
+Broadly speaking, performing a match of a string against a pattern
+involves the following steps:
+
+=over 5
+
+=item A. Compilation
+
+=over 5
+
+=item 1. Parsing for size
+
+=item 2. Parsing for construction
+
+=item 3. Peep-hole optimisation and analysis
+
+=back
+
+=item B. Execution
+
+=over 5
+
+=item 4. Start position and no-match optimisations
+
+=item 5. Program execution
+
+=back
+
+=back
+
+
+Where these steps occur in the actual execution of a perl program is
+determined by whether the pattern involves interpolating any string
+variables. If interpolation occurs, then compilation happens at run time. If it
+does not, then compilation is performed at compile time. (The C</o> modifier changes this,
+as does C<qr//> to a certain extent.) The engine doesn't really care that
+much.
+
+=head2 Compilation
+
+This code resides primarily in F<regcomp.c>, along with the header files
+F<regcomp.h>, F<regexp.h> and F<regnodes.h>.
+
+Compilation starts with C<pregcomp()>, which is mostly an initialisation
+wrapper which farms work out to two other routines for the heavy lifting: the
+first is C<reg()>, which is the start point for parsing; the second,
+C<study_chunk()>, is responsible for optimisation.
+
+Initialisation in C<pregcomp()> mostly involves the creation and data-filling
+of a special structure, C<RExC_state_t> (defined in F<regcomp.c>).
+Almost all internally-used routines in F<regcomp.h> take a pointer to one
+of these structures as their first argument, with the name C<pRExC_state>.
+This structure is used to store the compilation state and contains many
+fields. Likewise there are many macros which operate on this
+variable: anything that looks like C<RExC_xxxx> is a macro that operates on
+this pointer/structure.
+
+=head3 Parsing for size
+
+In this pass the input pattern is parsed in order to calculate how much
+space is needed for each regop we would need to emit. The size is also
+used to determine whether long jumps will be required in the program.
+
+This stage is controlled by the macro C<SIZE_ONLY> being set.
+
+The parse proceeds pretty much exactly as it does during the
+construction phase, except that most routines are short-circuited to
+change the size field C<RExC_size> and not do anything else.
+
+=head3 Parsing for construction
+
+Once the size of the program has been determined, the pattern is parsed
+again, but this time for real. Now C<SIZE_ONLY> will be false, and the
+actual construction can occur.
+
+C<reg()> is the start of the parse process. It is responsible for
+parsing an arbitrary chunk of pattern up to either the end of the
+string, or the first closing parenthesis it encounters in the pattern.
+This means it can be used to parse the top-level regex, or any section
+inside of a grouping parenthesis. It also handles the "special parens"
+that perl's regexes have. For instance when parsing C</x(?:foo)y/> C<reg()>
+will at one point be called to parse from the "?" symbol up to and
+including the ")".
+
+Additionally, C<reg()> is responsible for parsing the one or more
+branches from the pattern, and for "finishing them off" by correctly
+setting their next pointers. In order to do the parsing, it repeatedly
+calls out to C<regbranch()>, which is responsible for handling up to the
+first C<|> symbol it sees.
+
+C<regbranch()> in turn calls C<regpiece()> which
+handles "things" followed by a quantifier. In order to parse the
+"things", C<regatom()> is called. This is the lowest level routine, which
+parses out constant strings, character classes, and the
+various special symbols like C<$>. If C<regatom()> encounters a "("
+character it in turn calls C<reg()>.
+
+The routine C<regtail()> is called by both C<reg()> and C<regbranch()>
+in order to "set the tail pointer" correctly. When executing and
+we get to the end of a branch, we need to go to the node following the
+grouping parens. When parsing, however, we don't know where the end will
+be until we get there, so when we do we must go back and update the
+offsets as appropriate. C<regtail> is used to make this easier.
+
+A subtlety of the parsing process means that a regex like C</foo/> is
+originally parsed into an alternation with a single branch. It is only
+afterwards that the optimiser converts single branch alternations into the
+simpler form.
+
+=head3 Parse Call Graph and a Grammar
+
+The call graph looks like this:
+
+ reg() # parse a top level regex, or inside of parens
+ regbranch() # parse a single branch of an alternation
+ regpiece() # parse a pattern followed by a quantifier
+ regatom() # parse a simple pattern
+ regclass() # used to handle a class
+ reg() # used to handle a parenthesised subpattern
+ ....
+ ...
+ regtail() # finish off the branch
+ ...
+ regtail() # finish off the branch sequence. Tie each
+ # branch's tail to the tail of the sequence
+ # (NEW) In Debug mode this is
+ # regtail_study().
+
+A grammar form might be something like this:
+
+ atom : constant | class
+ quant : '*' | '+' | '?' | '{min,max}'
+ _branch: piece
+ | piece _branch
+ | nothing
+ branch: _branch
+ | _branch '|' branch
+ group : '(' branch ')'
+ _piece: atom | group
+ piece : _piece
+ | _piece quant
+
+=head3 Debug Output
+
+In the 5.9.x development version of perl you can C<< use re Debug => 'PARSE' >>
+to see some trace information about the parse process. We will start with some
+simple patterns and build up to more complex patterns.
+
+So when we parse C</foo/> we see something like the following table. The
+left shows what is being parsed, and the number indicates where the next regop
+would go. The stuff on the right is the trace output of the graph. The
+names are chosen to be short to make it less dense on the screen. 'tsdy'
+is a special form of C<regtail()> which does some extra analysis.
+
+ >foo< 1 reg
+ brnc
+ piec
+ atom
+ >< 4 tsdy~ EXACT <foo> (EXACT) (1)
+ ~ attach to END (3) offset to 2
+
+The resulting program then looks like:
+
+ 1: EXACT <foo>(3)
+ 3: END(0)
+
+As you can see, even though we parsed out a branch and a piece, it was ultimately
+only an atom. The final program shows us how things work. We have an C<EXACT> regop,
+followed by an C<END> regop. The number in parens indicates where the C<regnext> of
+the node goes. The C<regnext> of an C<END> regop is unused, as C<END> regops mean
+we have successfully matched. The number on the left indicates the position of
+the regop in the regnode array.
+
+Now let's try a harder pattern. We will add a quantifier, so now we have the pattern
+C</foo+/>. We will see that C<regbranch()> calls C<regpiece()> twice.
+
+ >foo+< 1 reg
+ brnc
+ piec
+ atom
+ >o+< 3 piec
+ atom
+ >< 6 tail~ EXACT <fo> (1)
+ 7 tsdy~ EXACT <fo> (EXACT) (1)
+ ~ PLUS (END) (3)
+ ~ attach to END (6) offset to 3
+
+And we end up with the program:
+
+ 1: EXACT <fo>(3)
+ 3: PLUS(6)
+ 4: EXACT <o>(0)
+ 6: END(0)
+
+Now we have a special case. The C<EXACT> regop has a C<regnext> of 0. This is
+because if it matches it should try to match itself again. The C<PLUS> regop
+handles the actual failure of the C<EXACT> regop and acts appropriately (going
+to regnode 6 if the C<EXACT> matched at least once, or failing if it didn't).
+
+Now for something much more complex: C</x(?:foo*|b[a][rR])(foo|bar)$/>
+
+ >x(?:foo*|b... 1 reg
+ brnc
+ piec
+ atom
+ >(?:foo*|b[... 3 piec
+ atom
+ >?:foo*|b[a... reg
+ >foo*|b[a][... brnc
+ piec
+ atom
+ >o*|b[a][rR... 5 piec
+ atom
+ >|b[a][rR])... 8 tail~ EXACT <fo> (3)
+ >b[a][rR])(... 9 brnc
+ 10 piec
+ atom
+ >[a][rR])(f... 12 piec
+ atom
+ >a][rR])(fo... clas
+ >[rR])(foo|... 14 tail~ EXACT <b> (10)
+ piec
+ atom
+ >rR])(foo|b... clas
+ >)(foo|bar)... 25 tail~ EXACT <a> (12)
+ tail~ BRANCH (3)
+ 26 tsdy~ BRANCH (END) (9)
+ ~ attach to TAIL (25) offset to 16
+ tsdy~ EXACT <fo> (EXACT) (4)
+ ~ STAR (END) (6)
+ ~ attach to TAIL (25) offset to 19
+ tsdy~ EXACT <b> (EXACT) (10)
+ ~ EXACT <a> (EXACT) (12)
+ ~ ANYOF[Rr] (END) (14)
+ ~ attach to TAIL (25) offset to 11
+ >(foo|bar)$< tail~ EXACT <x> (1)
+ piec
+ atom
+ >foo|bar)$< reg
+ 28 brnc
+ piec
+ atom
+ >|bar)$< 31 tail~ OPEN1 (26)
+ >bar)$< brnc
+ 32 piec
+ atom
+ >)$< 34 tail~ BRANCH (28)
+ 36 tsdy~ BRANCH (END) (31)
+ ~ attach to CLOSE1 (34) offset to 3
+ tsdy~ EXACT <foo> (EXACT) (29)
+ ~ attach to CLOSE1 (34) offset to 5
+ tsdy~ EXACT <bar> (EXACT) (32)
+ ~ attach to CLOSE1 (34) offset to 2
+ >$< tail~ BRANCH (3)
+ ~ BRANCH (9)
+ ~ TAIL (25)
+ piec
+ atom
+ >< 37 tail~ OPEN1 (26)
+ ~ BRANCH (28)
+ ~ BRANCH (31)
+ ~ CLOSE1 (34)
+ 38 tsdy~ EXACT <x> (EXACT) (1)
+ ~ BRANCH (END) (3)
+ ~ BRANCH (END) (9)
+ ~ TAIL (END) (25)
+ ~ OPEN1 (END) (26)
+ ~ BRANCH (END) (28)
+ ~ BRANCH (END) (31)
+ ~ CLOSE1 (END) (34)
+ ~ EOL (END) (36)
+ ~ attach to END (37) offset to 1
+
+Resulting in the program
+
+ 1: EXACT <x>(3)
+ 3: BRANCH(9)
+ 4: EXACT <fo>(6)
+ 6: STAR(26)
+ 7: EXACT <o>(0)
+ 9: BRANCH(25)
+ 10: EXACT <ba>(14)
+ 12: OPTIMIZED (2 nodes)
+ 14: ANYOF[Rr](26)
+ 25: TAIL(26)
+ 26: OPEN1(28)
+ 28: TRIE-EXACT(34)
+ [StS:1 Wds:2 Cs:6 Uq:5 #Sts:7 Mn:3 Mx:3 Stcls:bf]
+ <foo>
+ <bar>
+ 30: OPTIMIZED (4 nodes)
+ 34: CLOSE1(36)
+ 36: EOL(37)
+ 37: END(0)
+
+Here we can see a much more complex program, with various optimisations in
+play. At regnode 10 we see an example where a character class with only
+one character in it was turned into an C<EXACT> node. We can also see where
+an entire alternation was turned into a C<TRIE-EXACT> node. As a consequence,
+some of the regnodes have been marked as optimised away. We can see that
+the C<$> symbol has been converted into an C<EOL> regop, a special piece of
+code that looks for C<\n> or the end of the string.
+
+The next pointer for C<BRANCH>es is interesting in that it points at where
+execution should go if the branch fails. When executing, if the engine
+tries to traverse from a branch to a C<regnext> that isn't a branch then
+the engine will know that the entire set of branches has failed.
+
+=head3 Peep-hole Optimisation and Analysis
+
+The regular expression engine can be a weighty tool to wield. On long
+strings and complex patterns it can end up having to do a lot of work
+to find a match, and even more to decide that no match is possible.
+Consider a situation like the following pattern.
+
+ 'ababababababababababab' =~ /(a|b)*z/
+
+The C<(a|b)*> part can match at every char in the string, and then fail
+every time because there is no C<z> in the string. So obviously we can
+avoid using the regex engine unless there is a C<z> in the string.
+Likewise in a pattern like:
+
+ /foo(\w+)bar/
+
+In this case we know that the string must contain a C<foo> which must be
+followed by C<bar>. We can use Fast Boyer-Moore matching as implemented
+in C<fbm_instr()> to find the location of these strings. If they don't exist
+then we don't need to resort to the much more expensive regex engine.
+Even better, if they do exist then we can use their positions to
+reduce the search space that the regex engine needs to cover to determine
+if the entire pattern matches.
+
+There are various aspects of the pattern that can be used to facilitate
+optimisations along these lines:
+
+=over 5
+
+=item * anchored fixed strings
+
+=item * floating fixed strings
+
+=item * minimum and maximum length requirements
+
+=item * start class
+
+=item * Beginning/End of line positions
+
+=back
+
+Another form of optimisation that can occur is the post-parse "peep-hole"
+optimisation, where inefficient constructs are replaced by more efficient
+constructs. The C<TAIL> regops which are used during parsing to mark the end
+of branches and the end of groups are examples of this. These regops are used
+as place-holders during construction and "always match" so they can be
+"optimised away" by making the things that point to the C<TAIL> point to the
+thing that C<TAIL> points to, thus "skipping" the node.
+
+Another optimisation that can occur is that of "C<EXACT> merging" which is
+where two consecutive C<EXACT> nodes are merged into a single
+regop. An even more aggressive form of this is that a branch
+sequence of the form C<EXACT BRANCH ... EXACT> can be converted into a
+C<TRIE-EXACT> regop.
+
+All of this occurs in the routine C<study_chunk()> which uses a special
+structure C<scan_data_t> to store the analysis that it has performed, and
+does the "peep-hole" optimisations as it goes.
+
+The code involved in C<study_chunk()> is extremely cryptic. Be careful. :-)
+
+=head2 Execution
+
+Execution of a regex generally involves two phases, the first being
+finding the start point in the string where we should match from,
+and the second being running the regop interpreter.
+
+If we can tell that there is no valid start point then we don't bother running
+interpreter at all. Likewise, if we know from the analysis phase that we
+cannot detect a short-cut to the start position, we go straight to the
+interpreter.
+
+The two entry points are C<re_intuit_start()> and C<pregexec()>. These routines
+have a somewhat incestuous relationship with overlap between their functions,
+and C<pregexec()> may even call C<re_intuit_start()> on its own. Nevertheless
+other parts of the perl source code may call into either, or both.
+
+Execution of the interpreter itself used to be recursive, but thanks to the
+efforts of Dave Mitchell in the 5.9.x development track, that has changed: now an
+internal stack is maintained on the heap and the routine is fully
+iterative. This can make it tricky as the code is quite conservative
+about what state it stores, with the result that two consecutive lines in the
+code can actually be running in totally different contexts due to the
+simulated recursion.
+
+=head3 Start position and no-match optimisations
+
+C<re_intuit_start()> is responsible for handling start points and no-match
+optimisations as determined by the results of the analysis done by
+C<study_chunk()> (and described in L<Peep-hole Optimisation and Analysis>).
+
+The basic structure of this routine is to try to find the start- and/or
+end-points of where the pattern could match, and to ensure that the string
+is long enough to match the pattern. It tries to use more efficient
+methods over less efficient methods and may involve considerable
+cross-checking of constraints to find the place in the string that matches.
+For instance it may try to determine that a given fixed string must be
+not only present but a certain number of chars before the end of the
+string, or whatever.
+
+It calls several other routines, such as C<fbm_instr()> which does
+Fast Boyer Moore matching and C<find_byclass()> which is responsible for
+finding the start using the first mandatory regop in the program.
+
+When the optimisation criteria have been satisfied, C<reg_try()> is called
+to perform the match.
+
+=head3 Program execution
+
+C<pregexec()> is the main entry point for running a regex. It contains
+support for initialising the regex interpreter's state, running
+C<re_intuit_start()> if needed, and running the interpreter on the string
+from various start positions as needed. When it is necessary to use
+the regex interpreter C<pregexec()> calls C<regtry()>.
+
+C<regtry()> is the entry point into the regex interpreter. It expects
+as arguments a pointer to a C<regmatch_info> structure and a pointer to
+a string. It returns an integer 1 for success and a 0 for failure.
+It is basically a set-up wrapper around C<regmatch()>.
+
+C<regmatch> is the main "recursive loop" of the interpreter. It is
+basically a giant switch statement that implements a state machine, where
+the possible states are the regops themselves, plus a number of additional
+intermediate and failure states. A few of the states are implemented as
+subroutines but the bulk are inline code.
+
+=head1 MISCELLANEOUS
+
+=head2 Unicode and Localisation Support
+
+When dealing with strings containing characters that cannot be represented
+using an eight-bit character set, perl uses an internal representation
+that is a permissive version of Unicode's UTF-8 encoding[2]. This uses single
+bytes to represent characters from the ASCII character set, and sequences
+of two or more bytes for all other characters. (See L<perlunitut>
+for more information about the relationship between UTF-8 and perl's
+encoding, utf8. The difference isn't important for this discussion.)
+
+No matter how you look at it, Unicode support is going to be a pain in a
+regex engine. Tricks that might be fine when you have 256 possible
+characters often won't scale to handle the size of the UTF-8 character
+set. Things you can take for granted with ASCII may not be true with
+Unicode. For instance, in ASCII, it is safe to assume that
+C<sizeof(char1) == sizeof(char2)>, but in UTF-8 it isn't. Unicode case folding is
+vastly more complex than the simple rules of ASCII, and even when not
+using Unicode but only localised single byte encodings, things can get
+tricky (for example, B<LATIN SMALL LETTER SHARP S> (U+00DF, E<szlig>)
+should match 'SS' in localised case-insensitive matching).
+
+Making things worse is that UTF-8 support was a later addition to the
+regex engine (as it was to perl) and this necessarily made things a lot
+more complicated. Obviously it is easier to design a regex engine with
+Unicode support in mind from the beginning than it is to retrofit it to
+one that wasn't.
+
+Nearly all regops that involve looking at the input string have
+two cases, one for UTF-8, and one not. In fact, it's often more complex
+than that, as the pattern may be UTF-8 as well.
+
+Care must be taken when making changes to make sure that you handle
+UTF-8 properly, both at compile time and at execution time, including
+when the string and pattern are mismatched.
+
+The following comment in F<regcomp.h> gives an example of exactly how
+tricky this can be:
+
+ Two problematic code points in Unicode casefolding of EXACT nodes:
+
+ U+0390 - GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS
+ U+03B0 - GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS
+
+ which casefold to
+
+ Unicode UTF-8
+
+ U+03B9 U+0308 U+0301 0xCE 0xB9 0xCC 0x88 0xCC 0x81
+ U+03C5 U+0308 U+0301 0xCF 0x85 0xCC 0x88 0xCC 0x81
+
+ This means that in case-insensitive matching (or "loose matching",
+ as Unicode calls it), an EXACTF of length six (the UTF-8 encoded
+ byte length of the above casefolded versions) can match a target
+ string of length two (the byte length of UTF-8 encoded U+0390 or
+ U+03B0). This would rather mess up the minimum length computation.
+
+ What we'll do is to look for the tail four bytes, and then peek
+ at the preceding two bytes to see whether we need to decrease
+ the minimum length by four (six minus two).
+
+ Thanks to the design of UTF-8, there cannot be false matches:
+ A sequence of valid UTF-8 bytes cannot be a subsequence of
+ another valid sequence of UTF-8 bytes.
+
+
+=head2 Base Structures
+
+The C<regexp> structure described in L<perlreapi> is common to all
+regex engines. Two of its fields that are intended for the private use
+of the regex engine that compiled the pattern. These are the
+C<intflags> and pprivate members. The C<pprivate> is a void pointer to
+an arbitrary structure whose use and management is the responsibility
+of the compiling engine. perl will never modify either of these
+values. In the case of the stock engine the structure pointed to by
+C<pprivate> is called C<regexp_internal>.
+
+Its C<pprivate> and C<intflags> fields contain data
+specific to each engine.
+
+There are two structures used to store a compiled regular expression.
+One, the C<regexp> structure described in L<perlreapi> is populated by
+the engine currently being. used and some of its fields read by perl to
+implement things such as the stringification of C<qr//>.
+
+
+The other structure is pointed to be the C<regexp> struct's
+C<pprivate> and is in addition to C<intflags> in the same struct
+considered to be the property of the regex engine which compiled the
+regular expression;
+
+The regexp structure contains all the data that perl needs to be aware of
+to properly work with the regular expression. It includes data about
+optimisations that perl can use to determine if the regex engine should
+really be used, and various other control info that is needed to properly
+execute patterns in various contexts such as is the pattern anchored in
+some way, or what flags were used during the compile, or whether the
+program contains special constructs that perl needs to be aware of.
+
+In addition it contains two fields that are intended for the private use
+of the regex engine that compiled the pattern. These are the C<intflags>
+and pprivate members. The C<pprivate> is a void pointer to an arbitrary
+structure whose use and management is the responsibility of the compiling
+engine. perl will never modify either of these values.
+
+As mentioned earlier, in the case of the default engines, the C<pprivate>
+will be a pointer to a regexp_internal structure which holds the compiled
+program and any additional data that is private to the regex engine
+implementation.
+
+=head3 Perl's C<pprivate> structure
+
+The following structure is used as the C<pprivate> struct by perl's
+regex engine. Since it is specific to perl it is only of curiosity
+value to other engine implementations.
+
+ typedef struct regexp_internal {
+ regexp_paren_ofs *swap; /* Swap copy of *startp / *endp */
+ U32 *offsets; /* offset annotations 20001228 MJD
+ data about mapping the program to the
+ string*/
+ regnode *regstclass; /* Optional startclass as identified or constructed
+ by the optimiser */
+ struct reg_data *data; /* Additional miscellaneous data used by the program.
+ Used to make it easier to clone and free arbitrary
+ data that the regops need. Often the ARG field of
+ a regop is an index into this structure */
+ regnode program[1]; /* Unwarranted chumminess with compiler. */
+ } regexp_internal;
+
+=over 5
+
+=item C<swap>
+
+C<swap> formerly was an extra set of startp/endp stored in a
+C<regexp_paren_ofs> struct. This was used when the last successful match
+was from the same pattern as the current pattern, so that a partial
+match didn't overwrite the previous match's results, but it caused a
+problem with re-entrant code such as trying to build the UTF-8 swashes.
+Currently unused and left for backward compatibility with 5.10.0.
+
+=item C<offsets>
+
+Offsets holds a mapping of offset in the C<program>
+to offset in the C<precomp> string. This is only used by ActiveState's
+visual regex debugger.
+
+=item C<regstclass>
+
+Special regop that is used by C<re_intuit_start()> to check if a pattern
+can match at a certain position. For instance if the regex engine knows
+that the pattern must start with a 'Z' then it can scan the string until
+it finds one and then launch the regex engine from there. The routine
+that handles this is called C<find_by_class()>. Sometimes this field
+points at a regop embedded in the program, and sometimes it points at
+an independent synthetic regop that has been constructed by the optimiser.
+
+=item C<data>
+
+This field points at a reg_data structure, which is defined as follows
+
+ struct reg_data {
+ U32 count;
+ U8 *what;
+ void* data[1];
+ };
+
+This structure is used for handling data structures that the regex engine
+needs to handle specially during a clone or free operation on the compiled
+product. Each element in the data array has a corresponding element in the
+what array. During compilation regops that need special structures stored
+will add an element to each array using the add_data() routine and then store
+the index in the regop.
+
+=item C<program>
+
+Compiled program. Inlined into the structure so the entire struct can be
+treated as a single blob.
+
+=back
+
+=head1 SEE ALSO
+
+L<perlreapi>
+
+L<perlre>
+
+L<perlunitut>
+
+=head1 AUTHOR
+
+by Yves Orton, 2006.
+
+With excerpts from Perl, and contributions and suggestions from
+Ronald J. Kimball, Dave Mitchell, Dominic Dunlop, Mark Jason Dominus,
+Stephen McCamant, and David Landgren.
+
+=head1 LICENCE
+
+Same terms as Perl.
+
+=head1 REFERENCES
+
+[1] L<http://perl.plover.com/Rx/paper/>
+
+[2] L<http://www.unicode.org>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlrepository.pod b/Master/tlpkg/tlperl/lib/pods/perlrepository.pod
new file mode 100644
index 00000000000..3f1bb8adfc9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlrepository.pod
@@ -0,0 +1,908 @@
+=for comment
+Consistent formatting of this file is achieved with:
+ perl ./Porting/podtidy pod/perlrepository.pod
+
+=head1 NAME
+
+perlrepository - Using the Perl source repository
+
+=head1 SYNOPSIS
+
+All of Perl's source code is kept centrally in a Git repository at
+I<perl5.git.perl.org>. The repository contains many Perl revisions from
+Perl 1 onwards and all the revisions from Perforce, the version control
+system we were using previously. This repository is accessible in
+different ways.
+
+The full repository takes up about 80MB of disk space. A check out of
+the blead branch (that is, the main development branch, which contains
+bleadperl, the development version of perl 5) takes up about 160MB of
+disk space (including the repository). A build of bleadperl takes up
+about 200MB (including the repository and the check out).
+
+=head1 Getting access to the repository
+
+=head2 Read access via the web
+
+You may access the repository over the web. This allows you to browse
+the tree, see recent commits, subscribe to RSS feeds for the changes,
+search for particular commits and more. You may access it at:
+
+ http://perl5.git.perl.org/perl.git
+
+A mirror of the repository is found at:
+
+ http://github.com/mirrors/perl
+
+=head2 Read access via Git
+
+You will need a copy of Git for your computer. You can fetch a copy of
+the repository using the Git protocol (which uses port 9418):
+
+ % git clone git://perl5.git.perl.org/perl.git perl-git
+
+This clones the repository and makes a local copy in the F<perl-git>
+directory.
+
+If your local network does not allow you to use port 9418, then you can
+fetch a copy of the repository over HTTP (this is at least 4x slower):
+
+ % git clone http://perl5.git.perl.org/perl.git perl-http
+
+This clones the repository and makes a local copy in the F<perl-http>
+directory.
+
+=head2 Write access to the repository
+
+If you are a committer, then you can fetch a copy of the repository
+that you can push back on with:
+
+ % git clone ssh://perl5.git.perl.org/perl.git perl-ssh
+
+This clones the repository and makes a local copy in the F<perl-ssh>
+directory.
+
+If you cloned using the git protocol, which is faster than ssh, then
+you will need to modify the URL for the origin remote to enable
+pushing. To do that edit F<.git/config> with git-config(1) like
+this:
+
+ % git config remote.origin.url ssh://perl5.git.perl.org/perl.git
+
+You can also set up your user name and e-mail address. Most people do
+this once globally in their F<~/.gitconfig> by doing something like:
+
+ % git config --global user.name "Ævar Arnfjörð Bjarmason"
+ % git config --global user.email avarab@gmail.com
+
+However if you'd like to override that just for perl then execute then
+execute something like the following in F<perl-git>:
+
+ % git config user.email avar@cpan.org
+
+It is also possible to keep C<origin> as a git remote, and add a new
+remote for ssh access:
+
+ % git remote add camel perl5.git.perl.org:/perl.git
+
+This allows you to update your local repository by pulling from
+C<origin>, which is faster and doesn't require you to authenticate, and
+to push your changes back with the C<camel> remote:
+
+ % git fetch camel
+ % git push camel
+
+The C<fetch> command just updates the C<camel> refs, as the objects
+themselves should have been fetched when pulling from C<origin>.
+
+=head2 A note on camel and dromedary
+
+The committers have SSH access to the two servers that serve
+C<perl5.git.perl.org>. One is C<perl5.git.perl.org> itself (I<camel>),
+which is the 'master' repository. The second one is
+C<users.perl5.git.perl.org> (I<dromedary>), which can be used for
+general testing and development. Dromedary syncs the git tree from
+camel every few minutes, you should not push there. Both machines also
+have a full CPAN mirror in /srv/CPAN, please use this. To share files
+with the general public, dromedary serves your ~/public_html/ as
+C<http://users.perl5.git.perl.org/~yourlogin/>
+
+These hosts have fairly strict firewalls to the outside. Outgoing, only
+rsync, ssh and git are allowed. For http and ftp, you can use
+http://webproxy:3128 as proxy. Incoming, the firewall tries to detect
+attacks and blocks IP addresses with suspicious activity. This
+sometimes (but very rarely) has false positives and you might get
+blocked. The quickest way to get unblocked is to notify the admins.
+
+These two boxes are owned, hosted, and operated by booking.com. You can
+reach the sysadmins in #p5p on irc.perl.org or via mail to
+C<perl5-porters@perl.org>
+
+=head1 Overview of the repository
+
+Once you have changed into the repository directory, you can inspect
+it.
+
+After a clone the repository will contain a single local branch, which
+will be the current branch as well, as indicated by the asterisk.
+
+ % git branch
+ * blead
+
+Using the -a switch to C<branch> will also show the remote tracking
+branches in the repository:
+
+ % git branch -a
+ * blead
+ origin/HEAD
+ origin/blead
+ ...
+
+The branches that begin with "origin" correspond to the "git remote"
+that you cloned from (which is named "origin"). Each branch on the
+remote will be exactly tracked by theses branches. You should NEVER do
+work on these remote tracking branches. You only ever do work in a
+local branch. Local branches can be configured to automerge (on pull)
+from a designated remote tracking branch. This is the case with the
+default branch C<blead> which will be configured to merge from the
+remote tracking branch C<origin/blead>.
+
+You can see recent commits:
+
+ % git log
+
+And pull new changes from the repository, and update your local
+repository (must be clean first)
+
+ % git pull
+
+Assuming we are on the branch C<blead> immediately after a pull, this
+command would be more or less equivalent to:
+
+ % git fetch
+ % git merge origin/blead
+
+In fact if you want to update your local repository without touching
+your working directory you do:
+
+ % git fetch
+
+And if you want to update your remote-tracking branches for all defined
+remotes simultaneously you can do
+
+ % git remote update
+
+Neither of these last two commands will update your working directory,
+however both will update the remote-tracking branches in your
+repository.
+
+To make a local branch of a remote branch:
+
+ % git checkout -b maint-5.10 origin/maint-5.10
+
+To switch back to blead:
+
+ % git checkout blead
+
+=head2 Finding out your status
+
+The most common git command you will use will probably be
+
+ % git status
+
+This command will produce as output a description of the current state
+of the repository, including modified files and unignored untracked
+files, and in addition it will show things like what files have been
+staged for the next commit, and usually some useful information about
+how to change things. For instance the following:
+
+ $ git status
+ # On branch blead
+ # Your branch is ahead of 'origin/blead' by 1 commit.
+ #
+ # Changes to be committed:
+ # (use "git reset HEAD <file>..." to unstage)
+ #
+ # modified: pod/perlrepository.pod
+ #
+ # Changed but not updated:
+ # (use "git add <file>..." to update what will be committed)
+ #
+ # modified: pod/perlrepository.pod
+ #
+ # Untracked files:
+ # (use "git add <file>..." to include in what will be committed)
+ #
+ # deliberate.untracked
+
+This shows that there were changes to this document staged for commit,
+and that there were further changes in the working directory not yet
+staged. It also shows that there was an untracked file in the working
+directory, and as you can see shows how to change all of this. It also
+shows that there is one commit on the working branch C<blead> which has
+not been pushed to the C<origin> remote yet. B<NOTE>: that this output
+is also what you see as a template if you do not provide a message to
+C<git commit>.
+
+Assuming that you'd like to commit all the changes you've just made as a
+a single atomic unit, run this command:
+
+ % git commit -a
+
+(That C<-a> tells git to add every file you've changed to this commit.
+New files aren't automatically added to your commit when you use C<commit
+-a> If you want to add files or to commit some, but not all of your
+changes, have a look at the documentation for C<git add>.)
+
+Git will start up your favorite text editor, so that you can craft a
+commit message for your change. See L</Commit message> below for more
+information about what makes a good commit message.
+
+Once you've finished writing your commit message and exited your editor,
+git will write your change to disk and tell you something like this:
+
+ Created commit daf8e63: explain git status and stuff about remotes
+ 1 files changed, 83 insertions(+), 3 deletions(-)
+
+
+If you re-run C<git status>, you should see something like this:
+
+ % git status
+ # On branch blead
+ # Your branch is ahead of 'origin/blead' by 2 commits.
+ #
+ # Untracked files:
+ # (use "git add <file>..." to include in what will be committed)
+ #
+ # deliberate.untracked
+ nothing added to commit but untracked files present (use "git add" to track)
+
+
+When in doubt, before you do anything else, check your status and read
+it carefully, many questions are answered directly by the git status
+output.
+
+=head1 Submitting a patch
+
+If you have a patch in mind for Perl, you should first get a copy of
+the repository:
+
+ % git clone git://perl5.git.perl.org/perl.git perl-git
+
+Then change into the directory:
+
+ % cd perl-git
+
+Alternatively, if you already have a Perl repository, you should ensure
+that you're on the I<blead> branch, and your repository is up to date:
+
+ % git checkout blead
+ % git pull
+
+It's preferable to patch against the latest blead version, since this
+is where new development occurs for all changes other than critical bug
+fixes. Critical bug fix patches should be made against the relevant
+maint branches, or should be submitted with a note indicating all the
+branches where the fix should be applied.
+
+Now that we have everything up to date, we need to create a temporary
+new branch for these changes and switch into it:
+
+ % git checkout -b orange
+
+which is the short form of
+
+ % git branch orange
+ % git checkout orange
+
+Creating a topic branch makes it easier for the maintainers to rebase
+or merge back into the master blead for a more linear history. If you
+don't work on a topic branch the maintainer has to manually cherry
+pick your changes onto blead before they can be applied.
+
+That'll get you scolded on perl5-porters, so don't do that. Be
+Awesome.
+
+Then make your changes. For example, if Leon Brocard changes his name
+to Orange Brocard, we should change his name in the AUTHORS file:
+
+ % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
+
+You can see what files are changed:
+
+ % git status
+ # On branch orange
+ # Changes to be committed:
+ # (use "git reset HEAD <file>..." to unstage)
+ #
+ # modified: AUTHORS
+ #
+
+And you can see the changes:
+
+ % git diff
+ diff --git a/AUTHORS b/AUTHORS
+ index 293dd70..722c93e 100644
+ --- a/AUTHORS
+ +++ b/AUTHORS
+ @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
+ Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
+ Leif Huhn <leif@hale.dkstat.com>
+ Len Johnson <lenjay@ibm.net>
+ -Leon Brocard <acme@astray.com>
+ +Orange Brocard <acme@astray.com>
+ Les Peters <lpeters@aol.net>
+ Lesley Binks <lesley.binks@gmail.com>
+ Lincoln D. Stein <lstein@cshl.org>
+
+Now commit your change locally:
+
+ % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
+ Created commit 6196c1d: Rename Leon Brocard to Orange Brocard
+ 1 files changed, 1 insertions(+), 1 deletions(-)
+
+You can examine your last commit with:
+
+ % git show HEAD
+
+and if you are not happy with either the description or the patch
+itself you can fix it up by editing the files once more and then issue:
+
+ % git commit -a --amend
+
+Now you should create a patch file for all your local changes:
+
+ % git format-patch -M origin..
+ 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+
+You should now send an email to to
+L<perlbug@perl.org|mailto:perlbug@perl.org> with a description of your
+changes, and include this patch file as an attachment. In addition to
+being tracked by RT, mail to perlbug will automatically be forwarded
+to perl5-porters. You should only send patches to
+L<perl5-porters@perl.org|mailto:perl5-porters@perl.org> directly if the
+patch is not ready to be applied, but intended for discussion.
+
+See the next section for how to configure and use git to send these
+emails for you.
+
+If you want to delete your temporary branch, you may do so with:
+
+ % git checkout blead
+ % git branch -d orange
+ error: The branch 'orange' is not an ancestor of your current HEAD.
+ If you are sure you want to delete it, run 'git branch -D orange'.
+ % git branch -D orange
+ Deleted branch orange.
+
+=head2 Using git to send patch emails
+
+In your ~/git/perl repository, set the destination email to perl's bug
+tracker:
+
+ $ git config sendemail.to perlbug@perl.org
+
+Or maybe perl5-porters (discussed above):
+
+ $ git config sendemail.to perl5-porters@perl.org
+
+Then you can use git directly to send your patch emails:
+
+ $ git send-email 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+
+You may need to set some configuration variables for your particular
+email service provider. For example, to set your global git config to
+send email via a gmail account:
+
+ $ git config --global sendemail.smtpserver smtp.gmail.com
+ $ git config --global sendemail.smtpssl 1
+ $ git config --global sendemail.smtpuser YOURUSERNAME@gmail.com
+
+With this configuration, you will be prompted for your gmail password
+when you run 'git send-email'. You can also configure
+C<sendemail.smtppass> with your password if you don't care about having
+your password in the .gitconfig file.
+
+=head2 A note on derived files
+
+Be aware that many files in the distribution are derivative--avoid
+patching them, because git won't see the changes to them, and the build
+process will overwrite them. Patch the originals instead. Most
+utilities (like perldoc) are in this category, i.e. patch
+F<utils/perldoc.PL> rather than F<utils/perldoc>. Similarly, don't create
+patches for files under $src_root/ext from their copies found in
+$install_root/lib. If you are unsure about the proper location of a
+file that may have gotten copied while building the source
+distribution, consult the C<MANIFEST>.
+
+As a special case, several files are regenerated by 'make regen' if
+your patch alters C<embed.fnc>. These are needed for compilation, but
+are included in the distribution so that you can build perl without
+needing another perl to generate the files. You must test with these
+regenerated files, but it is preferred that you instead note that
+'make regen is needed' in both the email and the commit message, and
+submit your patch without them. If you're submitting a series of
+patches, it might be best to submit the regenerated changes
+immediately after the source-changes that caused them, so as to have
+as little effect as possible on the bisectability of your patchset.
+
+=for XXX
+What should we recommend about binary files now? Do we need anything?
+
+=head2 Getting your patch accepted
+
+If you are submitting a code patch there are several things that
+you need to do.
+
+=over 4
+
+=item Commit message
+
+As you craft each patch you intend to submit to the Perl core, it's
+important to write a good commit message.
+
+The first line of the commit message should be a short description and
+should skip the full stop. It should be no longer than the subject
+line of an E-Mail, 50 characters being a good rule of thumb.
+
+A lot of Git tools (Gitweb, GitHub, git log --pretty=oneline, ..) will
+only display the first line (cut off at 50 characters) when presenting
+commit summaries.
+
+The commit message should include description of the problem that the
+patch corrects or new functionality that the patch adds.
+
+As a general rule of thumb, your commit message should let a programmer
+with a reasonable familiarity with the Perl core quickly understand what
+you were trying to do, how you were trying to do it and why the change
+matters to Perl.
+
+=over 4
+
+=item What
+
+Your commit message should describe what part of the Perl core you're
+changing and what you expect your patch to do.
+
+=item Why
+
+Perhaps most importantly, your commit message should describe why the
+change you are making is important. When someone looks at your change
+in six months or six years, your intent should be clear. If you're
+deprecating a feature with the intent of later simplifying another bit
+of code, say so. If you're fixing a performance problem or adding a new
+feature to support some other bit of the core, mention that.
+
+=item How
+
+While it's not necessary for documentation changes, new tests or
+trivial patches, it's often worth explaining how your change works.
+Even if it's clear to you today, it may not be clear to a porter next
+month or next year.
+
+=back
+
+A commit message isn't intended to take the place of comments in your
+code. Commit messages should describe the change you made, while code
+comments should describe the current state of the code. If you've just
+implemented a new feature, complete with doc, tests and well-commented
+code, a brief commit message will often suffice. If, however, you've
+just changed a single character deep in the parser or lexer, you might
+need to write a small novel to ensure that future readers understand
+what you did and why you did it.
+
+=item Comments, Comments, Comments
+
+Be sure to adequately comment your code. While commenting every line
+is unnecessary, anything that takes advantage of side effects of
+operators, that creates changes that will be felt outside of the
+function being patched, or that others may find confusing should be
+documented. If you are going to err, it is better to err on the side
+of adding too many comments than too few.
+
+=item Style
+
+In general, please follow the particular style of the code you are
+patching.
+
+In particular, follow these general guidelines for patching Perl
+sources:
+
+ 8-wide tabs (no exceptions!)
+ 4-wide indents for code, 2-wide indents for nested CPP #defines
+ try hard not to exceed 79-columns
+ ANSI C prototypes
+ uncuddled elses and "K&R" style for indenting control constructs
+ no C++ style (//) comments
+ mark places that need to be revisited with XXX (and revisit often!)
+ opening brace lines up with "if" when conditional spans multiple
+ lines; should be at end-of-line otherwise
+ in function definitions, name starts in column 0 (return value is on
+ previous line)
+ single space after keywords that are followed by parens, no space
+ between function name and following paren
+ avoid assignments in conditionals, but if they're unavoidable, use
+ extra paren, e.g. "if (a && (b = c)) ..."
+ "return foo;" rather than "return(foo);"
+ "if (!foo) ..." rather than "if (foo == FALSE) ..." etc.
+
+=item Testsuite
+
+If your patch changes code (rather than just changing documentation) you
+should also include one or more test cases which illustrate the bug you're
+fixing or validate the new functionality you're adding. In general,
+you should update an existing test file rather than create a new one.
+
+Your testsuite additions should generally follow these guidelines
+(courtesy of Gurusamy Sarathy <gsar@activestate.com>):
+
+ Know what you're testing. Read the docs, and the source.
+ Tend to fail, not succeed.
+ Interpret results strictly.
+ Use unrelated features (this will flush out bizarre interactions).
+ Use non-standard idioms (otherwise you are not testing TIMTOWTDI).
+ Avoid using hardcoded test numbers whenever possible (the
+ EXPECTED/GOT found in t/op/tie.t is much more maintainable,
+ and gives better failure reports).
+ Give meaningful error messages when a test fails.
+ Avoid using qx// and system() unless you are testing for them. If you
+ do use them, make sure that you cover _all_ perl platforms.
+ Unlink any temporary files you create.
+ Promote unforeseen warnings to errors with $SIG{__WARN__}.
+ Be sure to use the libraries and modules shipped with the version
+ being tested, not those that were already installed.
+ Add comments to the code explaining what you are testing for.
+ Make updating the '1..42' string unnecessary. Or make sure that
+ you update it.
+ Test _all_ behaviors of a given operator, library, or function:
+ - All optional arguments
+ - Return values in various contexts (boolean, scalar, list, lvalue)
+ - Use both global and lexical variables
+ - Don't forget the exceptional, pathological cases.
+
+=back
+
+=head1 Accepting a patch
+
+If you have received a patch file generated using the above section,
+you should try out the patch.
+
+First we need to create a temporary new branch for these changes and
+switch into it:
+
+ % git checkout -b experimental
+
+Patches that were formatted by C<git format-patch> are applied with
+C<git am>:
+
+ % git am 0001-Rename-Leon-Brocard-to-Orange-Brocard.patch
+ Applying Rename Leon Brocard to Orange Brocard
+
+If just a raw diff is provided, it is also possible use this two-step
+process:
+
+ % git apply bugfix.diff
+ % git commit -a -m "Some fixing" --author="That Guy <that.guy@internets.com>"
+
+Now we can inspect the change:
+
+ % git show HEAD
+ commit b1b3dab48344cff6de4087efca3dbd63548ab5e2
+ Author: Leon Brocard <acme@astray.com>
+ Date: Fri Dec 19 17:02:59 2008 +0000
+
+ Rename Leon Brocard to Orange Brocard
+
+ diff --git a/AUTHORS b/AUTHORS
+ index 293dd70..722c93e 100644
+ --- a/AUTHORS
+ +++ b/AUTHORS
+ @@ -541,7 +541,7 @@ Lars Hecking <lhecking@nmrc.ucc.ie>
+ Laszlo Molnar <laszlo.molnar@eth.ericsson.se>
+ Leif Huhn <leif@hale.dkstat.com>
+ Len Johnson <lenjay@ibm.net>
+ -Leon Brocard <acme@astray.com>
+ +Orange Brocard <acme@astray.com>
+ Les Peters <lpeters@aol.net>
+ Lesley Binks <lesley.binks@gmail.com>
+ Lincoln D. Stein <lstein@cshl.org>
+
+If you are a committer to Perl and you think the patch is good, you can
+then merge it into blead then push it out to the main repository:
+
+ % git checkout blead
+ % git merge experimental
+ % git push
+
+If you want to delete your temporary branch, you may do so with:
+
+ % git checkout blead
+ % git branch -d experimental
+ error: The branch 'experimental' is not an ancestor of your current HEAD.
+ If you are sure you want to delete it, run 'git branch -D experimental'.
+ % git branch -D experimental
+ Deleted branch experimental.
+
+=head1 Cleaning a working directory
+
+The command C<git clean> can with varying arguments be used as a
+replacement for C<make clean>.
+
+To reset your working directory to a pristine condition you can do:
+
+ % git clean -dxf
+
+However, be aware this will delete ALL untracked content. You can use
+
+ % git clean -Xf
+
+to remove all ignored untracked files, such as build and test
+byproduct, but leave any manually created files alone.
+
+If you only want to cancel some uncommitted edits, you can use C<git
+checkout> and give it a list of files to be reverted, or C<git checkout
+-f> to revert them all.
+
+If you want to cancel one or several commits, you can use C<git reset>.
+
+=head1 Bisecting
+
+C<git> provides a built-in way to determine, with a binary search in
+the history, which commit should be blamed for introducing a given bug.
+
+Suppose that we have a script F<~/testcase.pl> that exits with C<0>
+when some behaviour is correct, and with C<1> when it's faulty. You need
+an helper script that automates building C<perl> and running the
+testcase:
+
+ % cat ~/run
+ #!/bin/sh
+ git clean -dxf
+ # If you can use ccache, add -Dcc=ccache\ gcc -Dld=gcc to the Configure line
+ # if Encode is not needed for the test, you can speed up the bisect by
+ # excluding it from the runs with -Dnoextensions=Encode
+ sh Configure -des -Dusedevel -Doptimize="-g"
+ test -f config.sh || exit 125
+ # Correct makefile for newer GNU gcc
+ perl -ni -we 'print unless /<(?:built-in|command)/' makefile x2p/makefile
+ # if you just need miniperl, replace test_prep with miniperl
+ make -j4 test_prep
+ [ -x ./perl ] || exit 125
+ ./perl -Ilib ~/testcase.pl
+ ret=$?
+ [ $ret -gt 127 ] && ret=127
+ git clean -dxf
+ exit $ret
+
+This script may return C<125> to indicate that the corresponding commit
+should be skipped. Otherwise, it returns the status of
+F<~/testcase.pl>.
+
+You first enter in bisect mode with:
+
+ % git bisect start
+
+For example, if the bug is present on C<HEAD> but wasn't in 5.10.0,
+C<git> will learn about this when you enter:
+
+ % git bisect bad
+ % git bisect good perl-5.10.0
+ Bisecting: 853 revisions left to test after this
+
+This results in checking out the median commit between C<HEAD> and
+C<perl-5.10.0>. You can then run the bisecting process with:
+
+ % git bisect run ~/run
+
+When the first bad commit is isolated, C<git bisect> will tell you so:
+
+ ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5 is first bad commit
+ commit ca4cfd28534303b82a216cfe83a1c80cbc3b9dc5
+ Author: Dave Mitchell <davem@fdisolutions.com>
+ Date: Sat Feb 9 14:56:23 2008 +0000
+
+ [perl #49472] Attributes + Unknown Error
+ ...
+
+ bisect run success
+
+You can peek into the bisecting process with C<git bisect log> and
+C<git bisect visualize>. C<git bisect reset> will get you out of bisect
+mode.
+
+Please note that the first C<good> state must be an ancestor of the
+first C<bad> state. If you want to search for the commit that I<solved>
+some bug, you have to negate your test case (i.e. exit with C<1> if OK
+and C<0> if not) and still mark the lower bound as C<good> and the
+upper as C<bad>. The "first bad commit" has then to be understood as
+the "first commit where the bug is solved".
+
+C<git help bisect> has much more information on how you can tweak your
+binary searches.
+
+=head1 Submitting a patch via GitHub
+
+GitHub is a website that makes it easy to fork and publish projects
+with Git. First you should set up a GitHub account and log in.
+
+Perl's git repository is mirrored on GitHub at this page:
+
+ http://github.com/mirrors/perl/tree/blead
+
+Visit the page and click the "fork" button. This clones the Perl git
+repository for you and provides you with "Your Clone URL" from which
+you should clone:
+
+ % git clone git@github.com:USERNAME/perl.git perl-github
+
+The same patch as above, using github might look like this:
+
+ % cd perl-github
+ % git remote add upstream git://perl5.git.perl.org/perl.git
+ % git pull upstream blead
+ % git checkout -b orange
+ % perl -pi -e 's{Leon Brocard}{Orange Brocard}' AUTHORS
+ % git commit -a -m 'Rename Leon Brocard to Orange Brocard'
+ % git push origin orange
+
+The orange branch has been pushed to GitHub, so you should now send an
+email (see L</Submitting a patch>) with a description of your changes
+and the following information:
+
+ http://github.com/USERNAME/perl/tree/orange
+ git@github.com:USERNAME/perl.git branch orange
+
+=head1 Merging from a branch via GitHub
+
+If someone has provided a branch via GitHub and you are a committer,
+you should use the following in your perl-ssh directory:
+
+ % git remote add dandv git://github.com/dandv/perl.git
+ % git fetch dandv
+
+Now you can see the differences between the branch and blead:
+
+ % git diff dandv/blead
+
+And you can see the commits:
+
+ % git log dandv/blead
+
+If you approve of a specific commit, you can cherry pick it:
+
+ % git cherry-pick 3adac458cb1c1d41af47fc66e67b49c8dec2323f
+
+Or you could just merge the whole branch if you like it all:
+
+ % git merge dandv/blead
+
+And then push back to the repository:
+
+ % git push
+
+
+=head1 Topic branches and rewriting history
+
+Individual committers should create topic branches under
+B<yourname>/B<some_descriptive_name>. Other committers should check
+with a topic branch's creator before making any change to it.
+
+The simplest way to create a remote topic branch that works on all
+versions of git is to push the current head as a new branch on the
+remote, then check it out locally:
+
+ $ branch="$yourname/$some_descriptive_name"
+ $ git push origin HEAD:$branch
+ $ git checkout -b $branch origin/$branch
+
+Users of git 1.7 or newer can do it in a more obvious manner:
+
+ $ branch="$yourname/$some_descriptive_name"
+ $ git checkout -b $branch
+ $ git push origin -u $branch
+
+If you are not the creator of B<yourname>/B<some_descriptive_name>, you
+might sometimes find that the original author has edited the branch's
+history. There are lots of good reasons for this. Sometimes, an author
+might simply be rebasing the branch onto a newer source point.
+Sometimes, an author might have found an error in an early commit which
+they wanted to fix before merging the branch to blead.
+
+Currently the master repository is configured to forbid
+non-fast-forward merges. This means that the branches within can not
+be rebased and pushed as a single step.
+
+The only way you will ever be allowed to rebase or modify the history
+of a pushed branch is to delete it and push it as a new branch under
+the same name. Please think carefully about doing this. It may be
+better to sequentially rename your branches so that it is easier for
+others working with you to cherry-pick their local changes onto the new
+version. (XXX: needs explanation).
+
+If you want to rebase a personal topic branch, you will have to delete
+your existing topic branch and push as a new version of it. You can do
+this via the following formula (see the explanation about C<refspec>'s
+in the git push documentation for details) after you have rebased your
+branch:
+
+ # first rebase
+ $ git checkout $user/$topic
+ $ git fetch
+ $ git rebase origin/blead
+
+ # then "delete-and-push"
+ $ git push origin :$user/$topic
+ $ git push origin $user/$topic
+
+B<NOTE:> it is forbidden at the repository level to delete any of the
+"primary" branches. That is any branch matching
+C<m!^(blead|maint|perl)!>. Any attempt to do so will result in git
+producing an error like this:
+
+ $ git push origin :blead
+ *** It is forbidden to delete blead/maint branches in this repository
+ error: hooks/update exited with error code 1
+ error: hook declined to update refs/heads/blead
+ To ssh://perl5.git.perl.org/perl
+ ! [remote rejected] blead (hook declined)
+ error: failed to push some refs to 'ssh://perl5.git.perl.org/perl'
+
+As a matter of policy we do B<not> edit the history of the blead and
+maint-* branches. If a typo (or worse) sneaks into a commit to blead or
+maint-*, we'll fix it in another commit. The only types of updates
+allowed on these branches are "fast-forward's", where all history is
+preserved.
+
+Annotated tags in the canonical perl.git repository will never be
+deleted or modified. Think long and hard about whether you want to push
+a local tag to perl.git before doing so. (Pushing unannotated tags is
+not allowed.)
+
+=head1 Committing to maintenance versions
+
+Maintenance versions should only be altered to add critical bug
+fixes, see L<perlpolicy>.
+
+To commit to a maintenance version of perl, you need to create a local
+tracking branch:
+
+ % git checkout --track -b maint-5.005 origin/maint-5.005
+
+This creates a local branch named C<maint-5.005>, which tracks the
+remote branch C<origin/maint-5.005>. Then you can pull, commit, merge
+and push as before.
+
+You can also cherry-pick commits from blead and another branch, by
+using the C<git cherry-pick> command. It is recommended to use the
+B<-x> option to C<git cherry-pick> in order to record the SHA1 of the
+original commit in the new commit message.
+
+=head1 Grafts
+
+The perl history contains one mistake which was not caught in the
+conversion: a merge was recorded in the history between blead and
+maint-5.10 where no merge actually occurred. Due to the nature of git,
+this is now impossible to fix in the public repository. You can remove
+this mis-merge locally by adding the following line to your
+C<.git/info/grafts> file:
+
+ 296f12bbbbaa06de9be9d09d3dcf8f4528898a49 434946e0cb7a32589ed92d18008aaa1d88515930
+
+It is particularly important to have this graft line if any bisecting
+is done in the area of the "merge" in question.
+
+=head1 SEE ALSO
+
+=over
+
+=item *
+
+The git documentation, accessible via the C<git help> command
+
+=item *
+
+L<perlpolicy> - Perl core development policy
+
+=back
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlrequick.pod b/Master/tlpkg/tlperl/lib/pods/perlrequick.pod
new file mode 100644
index 00000000000..4b5e19a0fb1
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlrequick.pod
@@ -0,0 +1,516 @@
+=head1 NAME
+
+perlrequick - Perl regular expressions quick start
+
+=head1 DESCRIPTION
+
+This page covers the very basics of understanding, creating and
+using regular expressions ('regexes') in Perl.
+
+
+=head1 The Guide
+
+=head2 Simple word matching
+
+The simplest regex is simply a word, or more generally, a string of
+characters. A regex consisting of a word matches any string that
+contains that word:
+
+ "Hello World" =~ /World/; # matches
+
+In this statement, C<World> is a regex and the C<//> enclosing
+C</World/> tells perl to search a string for a match. The operator
+C<=~> associates the string with the regex match and produces a true
+value if the regex matched, or false if the regex did not match. In
+our case, C<World> matches the second word in C<"Hello World">, so the
+expression is true. This idea has several variations.
+
+Expressions like this are useful in conditionals:
+
+ print "It matches\n" if "Hello World" =~ /World/;
+
+The sense of the match can be reversed by using C<!~> operator:
+
+ print "It doesn't match\n" if "Hello World" !~ /World/;
+
+The literal string in the regex can be replaced by a variable:
+
+ $greeting = "World";
+ print "It matches\n" if "Hello World" =~ /$greeting/;
+
+If you're matching against C<$_>, the C<$_ =~> part can be omitted:
+
+ $_ = "Hello World";
+ print "It matches\n" if /World/;
+
+Finally, the C<//> default delimiters for a match can be changed to
+arbitrary delimiters by putting an C<'m'> out front:
+
+ "Hello World" =~ m!World!; # matches, delimited by '!'
+ "Hello World" =~ m{World}; # matches, note the matching '{}'
+ "/usr/bin/perl" =~ m"/perl"; # matches after '/usr/bin',
+ # '/' becomes an ordinary char
+
+Regexes must match a part of the string I<exactly> in order for the
+statement to be true:
+
+ "Hello World" =~ /world/; # doesn't match, case sensitive
+ "Hello World" =~ /o W/; # matches, ' ' is an ordinary char
+ "Hello World" =~ /World /; # doesn't match, no ' ' at end
+
+perl will always match at the earliest possible point in the string:
+
+ "Hello World" =~ /o/; # matches 'o' in 'Hello'
+ "That hat is red" =~ /hat/; # matches 'hat' in 'That'
+
+Not all characters can be used 'as is' in a match. Some characters,
+called B<metacharacters>, are reserved for use in regex notation.
+The metacharacters are
+
+ {}[]()^$.|*+?\
+
+A metacharacter can be matched by putting a backslash before it:
+
+ "2+2=4" =~ /2+2/; # doesn't match, + is a metacharacter
+ "2+2=4" =~ /2\+2/; # matches, \+ is treated like an ordinary +
+ 'C:\WIN32' =~ /C:\\WIN/; # matches
+ "/usr/bin/perl" =~ /\/usr\/bin\/perl/; # matches
+
+In the last regex, the forward slash C<'/'> is also backslashed,
+because it is used to delimit the regex.
+
+Non-printable ASCII characters are represented by B<escape sequences>.
+Common examples are C<\t> for a tab, C<\n> for a newline, and C<\r>
+for a carriage return. Arbitrary bytes are represented by octal
+escape sequences, e.g., C<\033>, or hexadecimal escape sequences,
+e.g., C<\x1B>:
+
+ "1000\t2000" =~ m(0\t2) # matches
+ "cat" =~ /\143\x61\x74/ # matches in ASCII, but a weird way to spell cat
+
+Regexes are treated mostly as double quoted strings, so variable
+substitution works:
+
+ $foo = 'house';
+ 'cathouse' =~ /cat$foo/; # matches
+ 'housecat' =~ /${foo}cat/; # matches
+
+With all of the regexes above, if the regex matched anywhere in the
+string, it was considered a match. To specify I<where> it should
+match, we would use the B<anchor> metacharacters C<^> and C<$>. The
+anchor C<^> means match at the beginning of the string and the anchor
+C<$> means match at the end of the string, or before a newline at the
+end of the string. Some examples:
+
+ "housekeeper" =~ /keeper/; # matches
+ "housekeeper" =~ /^keeper/; # doesn't match
+ "housekeeper" =~ /keeper$/; # matches
+ "housekeeper\n" =~ /keeper$/; # matches
+ "housekeeper" =~ /^housekeeper$/; # matches
+
+=head2 Using character classes
+
+A B<character class> allows a set of possible characters, rather than
+just a single character, to match at a particular point in a regex.
+Character classes are denoted by brackets C<[...]>, with the set of
+characters to be possibly matched inside. Here are some examples:
+
+ /cat/; # matches 'cat'
+ /[bcr]at/; # matches 'bat', 'cat', or 'rat'
+ "abc" =~ /[cab]/; # matches 'a'
+
+In the last statement, even though C<'c'> is the first character in
+the class, the earliest point at which the regex can match is C<'a'>.
+
+ /[yY][eE][sS]/; # match 'yes' in a case-insensitive way
+ # 'yes', 'Yes', 'YES', etc.
+ /yes/i; # also match 'yes' in a case-insensitive way
+
+The last example shows a match with an C<'i'> B<modifier>, which makes
+the match case-insensitive.
+
+Character classes also have ordinary and special characters, but the
+sets of ordinary and special characters inside a character class are
+different than those outside a character class. The special
+characters for a character class are C<-]\^$> and are matched using an
+escape:
+
+ /[\]c]def/; # matches ']def' or 'cdef'
+ $x = 'bcr';
+ /[$x]at/; # matches 'bat, 'cat', or 'rat'
+ /[\$x]at/; # matches '$at' or 'xat'
+ /[\\$x]at/; # matches '\at', 'bat, 'cat', or 'rat'
+
+The special character C<'-'> acts as a range operator within character
+classes, so that the unwieldy C<[0123456789]> and C<[abc...xyz]>
+become the svelte C<[0-9]> and C<[a-z]>:
+
+ /item[0-9]/; # matches 'item0' or ... or 'item9'
+ /[0-9a-fA-F]/; # matches a hexadecimal digit
+
+If C<'-'> is the first or last character in a character class, it is
+treated as an ordinary character.
+
+The special character C<^> in the first position of a character class
+denotes a B<negated character class>, which matches any character but
+those in the brackets. Both C<[...]> and C<[^...]> must match a
+character, or the match fails. Then
+
+ /[^a]at/; # doesn't match 'aat' or 'at', but matches
+ # all other 'bat', 'cat, '0at', '%at', etc.
+ /[^0-9]/; # matches a non-numeric character
+ /[a^]at/; # matches 'aat' or '^at'; here '^' is ordinary
+
+Perl has several abbreviations for common character classes:
+
+=over 4
+
+=item *
+
+\d is a digit and represents
+
+ [0-9]
+
+=item *
+
+\s is a whitespace character and represents
+
+ [\ \t\r\n\f]
+
+=item *
+
+\w is a word character (alphanumeric or _) and represents
+
+ [0-9a-zA-Z_]
+
+=item *
+
+\D is a negated \d; it represents any character but a digit
+
+ [^0-9]
+
+=item *
+
+\S is a negated \s; it represents any non-whitespace character
+
+ [^\s]
+
+=item *
+
+\W is a negated \w; it represents any non-word character
+
+ [^\w]
+
+=item *
+
+The period '.' matches any character but "\n"
+
+=back
+
+The C<\d\s\w\D\S\W> abbreviations can be used both inside and outside
+of character classes. Here are some in use:
+
+ /\d\d:\d\d:\d\d/; # matches a hh:mm:ss time format
+ /[\d\s]/; # matches any digit or whitespace character
+ /\w\W\w/; # matches a word char, followed by a
+ # non-word char, followed by a word char
+ /..rt/; # matches any two chars, followed by 'rt'
+ /end\./; # matches 'end.'
+ /end[.]/; # same thing, matches 'end.'
+
+The S<B<word anchor> > C<\b> matches a boundary between a word
+character and a non-word character C<\w\W> or C<\W\w>:
+
+ $x = "Housecat catenates house and cat";
+ $x =~ /\bcat/; # matches cat in 'catenates'
+ $x =~ /cat\b/; # matches cat in 'housecat'
+ $x =~ /\bcat\b/; # matches 'cat' at end of string
+
+In the last example, the end of the string is considered a word
+boundary.
+
+=head2 Matching this or that
+
+We can match different character strings with the B<alternation>
+metacharacter C<'|'>. To match C<dog> or C<cat>, we form the regex
+C<dog|cat>. As before, perl will try to match the regex at the
+earliest possible point in the string. At each character position,
+perl will first try to match the first alternative, C<dog>. If
+C<dog> doesn't match, perl will then try the next alternative, C<cat>.
+If C<cat> doesn't match either, then the match fails and perl moves to
+the next position in the string. Some examples:
+
+ "cats and dogs" =~ /cat|dog|bird/; # matches "cat"
+ "cats and dogs" =~ /dog|cat|bird/; # matches "cat"
+
+Even though C<dog> is the first alternative in the second regex,
+C<cat> is able to match earlier in the string.
+
+ "cats" =~ /c|ca|cat|cats/; # matches "c"
+ "cats" =~ /cats|cat|ca|c/; # matches "cats"
+
+At a given character position, the first alternative that allows the
+regex match to succeed will be the one that matches. Here, all the
+alternatives match at the first string position, so the first matches.
+
+=head2 Grouping things and hierarchical matching
+
+The B<grouping> metacharacters C<()> allow a part of a regex to be
+treated as a single unit. Parts of a regex are grouped by enclosing
+them in parentheses. The regex C<house(cat|keeper)> means match
+C<house> followed by either C<cat> or C<keeper>. Some more examples
+are
+
+ /(a|b)b/; # matches 'ab' or 'bb'
+ /(^a|b)c/; # matches 'ac' at start of string or 'bc' anywhere
+
+ /house(cat|)/; # matches either 'housecat' or 'house'
+ /house(cat(s|)|)/; # matches either 'housecats' or 'housecat' or
+ # 'house'. Note groups can be nested.
+
+ "20" =~ /(19|20|)\d\d/; # matches the null alternative '()\d\d',
+ # because '20\d\d' can't match
+
+=head2 Extracting matches
+
+The grouping metacharacters C<()> also allow the extraction of the
+parts of a string that matched. For each grouping, the part that
+matched inside goes into the special variables C<$1>, C<$2>, etc.
+They can be used just as ordinary variables:
+
+ # extract hours, minutes, seconds
+ $time =~ /(\d\d):(\d\d):(\d\d)/; # match hh:mm:ss format
+ $hours = $1;
+ $minutes = $2;
+ $seconds = $3;
+
+In list context, a match C</regex/> with groupings will return the
+list of matched values C<($1,$2,...)>. So we could rewrite it as
+
+ ($hours, $minutes, $second) = ($time =~ /(\d\d):(\d\d):(\d\d)/);
+
+If the groupings in a regex are nested, C<$1> gets the group with the
+leftmost opening parenthesis, C<$2> the next opening parenthesis,
+etc. For example, here is a complex regex and the matching variables
+indicated below it:
+
+ /(ab(cd|ef)((gi)|j))/;
+ 1 2 34
+
+Associated with the matching variables C<$1>, C<$2>, ... are
+the B<backreferences> C<\1>, C<\2>, ... Backreferences are
+matching variables that can be used I<inside> a regex:
+
+ /(\w\w\w)\s\1/; # find sequences like 'the the' in string
+
+C<$1>, C<$2>, ... should only be used outside of a regex, and C<\1>,
+C<\2>, ... only inside a regex.
+
+=head2 Matching repetitions
+
+The B<quantifier> metacharacters C<?>, C<*>, C<+>, and C<{}> allow us
+to determine the number of repeats of a portion of a regex we
+consider to be a match. Quantifiers are put immediately after the
+character, character class, or grouping that we want to specify. They
+have the following meanings:
+
+=over 4
+
+=item *
+
+C<a?> = match 'a' 1 or 0 times
+
+=item *
+
+C<a*> = match 'a' 0 or more times, i.e., any number of times
+
+=item *
+
+C<a+> = match 'a' 1 or more times, i.e., at least once
+
+=item *
+
+C<a{n,m}> = match at least C<n> times, but not more than C<m>
+times.
+
+=item *
+
+C<a{n,}> = match at least C<n> or more times
+
+=item *
+
+C<a{n}> = match exactly C<n> times
+
+=back
+
+Here are some examples:
+
+ /[a-z]+\s+\d*/; # match a lowercase word, at least some space, and
+ # any number of digits
+ /(\w+)\s+\1/; # match doubled words of arbitrary length
+ $year =~ /\d{2,4}/; # make sure year is at least 2 but not more
+ # than 4 digits
+ $year =~ /\d{4}|\d{2}/; # better match; throw out 3 digit dates
+
+These quantifiers will try to match as much of the string as possible,
+while still allowing the regex to match. So we have
+
+ $x = 'the cat in the hat';
+ $x =~ /^(.*)(at)(.*)$/; # matches,
+ # $1 = 'the cat in the h'
+ # $2 = 'at'
+ # $3 = '' (0 matches)
+
+The first quantifier C<.*> grabs as much of the string as possible
+while still having the regex match. The second quantifier C<.*> has
+no string left to it, so it matches 0 times.
+
+=head2 More matching
+
+There are a few more things you might want to know about matching
+operators. In the code
+
+ $pattern = 'Seuss';
+ while (<>) {
+ print if /$pattern/;
+ }
+
+perl has to re-evaluate C<$pattern> each time through the loop. If
+C<$pattern> won't be changing, use the C<//o> modifier, to only
+perform variable substitutions once. If you don't want any
+substitutions at all, use the special delimiter C<m''>:
+
+ @pattern = ('Seuss');
+ m/@pattern/; # matches 'Seuss'
+ m'@pattern'; # matches the literal string '@pattern'
+
+The global modifier C<//g> allows the matching operator to match
+within a string as many times as possible. In scalar context,
+successive matches against a string will have C<//g> jump from match
+to match, keeping track of position in the string as it goes along.
+You can get or set the position with the C<pos()> function.
+For example,
+
+ $x = "cat dog house"; # 3 words
+ while ($x =~ /(\w+)/g) {
+ print "Word is $1, ends at position ", pos $x, "\n";
+ }
+
+prints
+
+ Word is cat, ends at position 3
+ Word is dog, ends at position 7
+ Word is house, ends at position 13
+
+A failed match or changing the target string resets the position. If
+you don't want the position reset after failure to match, add the
+C<//c>, as in C</regex/gc>.
+
+In list context, C<//g> returns a list of matched groupings, or if
+there are no groupings, a list of matches to the whole regex. So
+
+ @words = ($x =~ /(\w+)/g); # matches,
+ # $word[0] = 'cat'
+ # $word[1] = 'dog'
+ # $word[2] = 'house'
+
+=head2 Search and replace
+
+Search and replace is performed using C<s/regex/replacement/modifiers>.
+The C<replacement> is a Perl double quoted string that replaces in the
+string whatever is matched with the C<regex>. The operator C<=~> is
+also used here to associate a string with C<s///>. If matching
+against C<$_>, the S<C<$_ =~> > can be dropped. If there is a match,
+C<s///> returns the number of substitutions made, otherwise it returns
+false. Here are a few examples:
+
+ $x = "Time to feed the cat!";
+ $x =~ s/cat/hacker/; # $x contains "Time to feed the hacker!"
+ $y = "'quoted words'";
+ $y =~ s/^'(.*)'$/$1/; # strip single quotes,
+ # $y contains "quoted words"
+
+With the C<s///> operator, the matched variables C<$1>, C<$2>, etc.
+are immediately available for use in the replacement expression. With
+the global modifier, C<s///g> will search and replace all occurrences
+of the regex in the string:
+
+ $x = "I batted 4 for 4";
+ $x =~ s/4/four/; # $x contains "I batted four for 4"
+ $x = "I batted 4 for 4";
+ $x =~ s/4/four/g; # $x contains "I batted four for four"
+
+The evaluation modifier C<s///e> wraps an C<eval{...}> around the
+replacement string and the evaluated result is substituted for the
+matched substring. Some examples:
+
+ # reverse all the words in a string
+ $x = "the cat in the hat";
+ $x =~ s/(\w+)/reverse $1/ge; # $x contains "eht tac ni eht tah"
+
+ # convert percentage to decimal
+ $x = "A 39% hit rate";
+ $x =~ s!(\d+)%!$1/100!e; # $x contains "A 0.39 hit rate"
+
+The last example shows that C<s///> can use other delimiters, such as
+C<s!!!> and C<s{}{}>, and even C<s{}//>. If single quotes are used
+C<s'''>, then the regex and replacement are treated as single quoted
+strings.
+
+=head2 The split operator
+
+C<split /regex/, string> splits C<string> into a list of substrings
+and returns that list. The regex determines the character sequence
+that C<string> is split with respect to. For example, to split a
+string into words, use
+
+ $x = "Calvin and Hobbes";
+ @word = split /\s+/, $x; # $word[0] = 'Calvin'
+ # $word[1] = 'and'
+ # $word[2] = 'Hobbes'
+
+To extract a comma-delimited list of numbers, use
+
+ $x = "1.618,2.718, 3.142";
+ @const = split /,\s*/, $x; # $const[0] = '1.618'
+ # $const[1] = '2.718'
+ # $const[2] = '3.142'
+
+If the empty regex C<//> is used, the string is split into individual
+characters. If the regex has groupings, then the list produced contains
+the matched substrings from the groupings as well:
+
+ $x = "/usr/bin";
+ @parts = split m!(/)!, $x; # $parts[0] = ''
+ # $parts[1] = '/'
+ # $parts[2] = 'usr'
+ # $parts[3] = '/'
+ # $parts[4] = 'bin'
+
+Since the first character of $x matched the regex, C<split> prepended
+an empty initial element to the list.
+
+=head1 BUGS
+
+None.
+
+=head1 SEE ALSO
+
+This is just a quick start guide. For a more in-depth tutorial on
+regexes, see L<perlretut> and for the reference page, see L<perlre>.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 2000 Mark Kvale
+All rights reserved.
+
+This document may be distributed under the same terms as Perl itself.
+
+=head2 Acknowledgments
+
+The author would like to thank Mark-Jason Dominus, Tom Christiansen,
+Ilya Zakharevich, Brad Hughes, and Mike Giroux for all their helpful
+comments.
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlreref.pod b/Master/tlpkg/tlperl/lib/pods/perlreref.pod
new file mode 100644
index 00000000000..ad970d2dce7
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlreref.pod
@@ -0,0 +1,392 @@
+=head1 NAME
+
+perlreref - Perl Regular Expressions Reference
+
+=head1 DESCRIPTION
+
+This is a quick reference to Perl's regular expressions.
+For full information see L<perlre> and L<perlop>, as well
+as the L</"SEE ALSO"> section in this document.
+
+=head2 OPERATORS
+
+C<=~> determines to which variable the regex is applied.
+In its absence, $_ is used.
+
+ $var =~ /foo/;
+
+C<!~> determines to which variable the regex is applied,
+and negates the result of the match; it returns
+false if the match succeeds, and true if it fails.
+
+ $var !~ /foo/;
+
+C<m/pattern/msixpogc> searches a string for a pattern match,
+applying the given options.
+
+ m Multiline mode - ^ and $ match internal lines
+ s match as a Single line - . matches \n
+ i case-Insensitive
+ x eXtended legibility - free whitespace and comments
+ p Preserve a copy of the matched string -
+ ${^PREMATCH}, ${^MATCH}, ${^POSTMATCH} will be defined.
+ o compile pattern Once
+ g Global - all occurrences
+ c don't reset pos on failed matches when using /g
+
+If 'pattern' is an empty string, the last I<successfully> matched
+regex is used. Delimiters other than '/' may be used for both this
+operator and the following ones. The leading C<m> can be omitted
+if the delimiter is '/'.
+
+C<qr/pattern/msixpo> lets you store a regex in a variable,
+or pass one around. Modifiers as for C<m//>, and are stored
+within the regex.
+
+C<s/pattern/replacement/msixpogce> substitutes matches of
+'pattern' with 'replacement'. Modifiers as for C<m//>,
+with one addition:
+
+ e Evaluate 'replacement' as an expression
+
+'e' may be specified multiple times. 'replacement' is interpreted
+as a double quoted string unless a single-quote (C<'>) is the delimiter.
+
+C<?pattern?> is like C<m/pattern/> but matches only once. No alternate
+delimiters can be used. Must be reset with reset().
+
+=head2 SYNTAX
+
+ \ Escapes the character immediately following it
+ . Matches any single character except a newline (unless /s is
+ used)
+ ^ Matches at the beginning of the string (or line, if /m is used)
+ $ Matches at the end of the string (or line, if /m is used)
+ * Matches the preceding element 0 or more times
+ + Matches the preceding element 1 or more times
+ ? Matches the preceding element 0 or 1 times
+ {...} Specifies a range of occurrences for the element preceding it
+ [...] Matches any one of the characters contained within the brackets
+ (...) Groups subexpressions for capturing to $1, $2...
+ (?:...) Groups subexpressions without capturing (cluster)
+ | Matches either the subexpression preceding or following it
+ \1, \2, \3 ... Matches the text from the Nth group
+ \g1 or \g{1}, \g2 ... Matches the text from the Nth group
+ \g-1 or \g{-1}, \g-2 ... Matches the text from the Nth previous group
+ \g{name} Named backreference
+ \k<name> Named backreference
+ \k'name' Named backreference
+ (?P=name) Named backreference (python syntax)
+
+=head2 ESCAPE SEQUENCES
+
+These work as in normal strings.
+
+ \a Alarm (beep)
+ \e Escape
+ \f Formfeed
+ \n Newline
+ \r Carriage return
+ \t Tab
+ \037 Char whose ordinal is the 3 octal digits, max \777
+ \o{2307} Char whose ordinal is the octal number, unrestricted
+ \x7f Char whose ordinal is the 2 hex digits, max \xFF
+ \x{263a} Char whose ordinal is the hex number, unrestricted
+ \cx Control-x
+ \N{name} A named Unicode character
+ \N{U+263D} A Unicode character by hex ordinal
+
+ \l Lowercase next character
+ \u Titlecase next character
+ \L Lowercase until \E
+ \U Uppercase until \E
+ \Q Disable pattern metacharacters until \E
+ \E End modification
+
+For Titlecase, see L</Titlecase>.
+
+This one works differently from normal strings:
+
+ \b An assertion, not backspace, except in a character class
+
+=head2 CHARACTER CLASSES
+
+ [amy] Match 'a', 'm' or 'y'
+ [f-j] Dash specifies "range"
+ [f-j-] Dash escaped or at start or end means 'dash'
+ [^f-j] Caret indicates "match any character _except_ these"
+
+The following sequences (except C<\N>) work within or without a character class.
+The first six are locale aware, all are Unicode aware. See L<perllocale>
+and L<perlunicode> for details.
+
+ \d A digit
+ \D A nondigit
+ \w A word character
+ \W A non-word character
+ \s A whitespace character
+ \S A non-whitespace character
+ \h An horizontal whitespace
+ \H A non horizontal whitespace
+ \N A non newline (when not followed by '{NAME}'; experimental;
+ not valid in a character class; equivalent to [^\n]; it's
+ like '.' without /s modifier)
+ \v A vertical whitespace
+ \V A non vertical whitespace
+ \R A generic newline (?>\v|\x0D\x0A)
+
+ \C Match a byte (with Unicode, '.' matches a character)
+ \pP Match P-named (Unicode) property
+ \p{...} Match Unicode property with name longer than 1 character
+ \PP Match non-P
+ \P{...} Match lack of Unicode property with name longer than 1 char
+ \X Match Unicode extended grapheme cluster
+
+POSIX character classes and their Unicode and Perl equivalents:
+
+ ASCII- Full-
+ range range backslash
+ POSIX \p{...} \p{} sequence Description
+ -----------------------------------------------------------------------
+ alnum PosixAlnum Alnum Alpha plus Digit
+ alpha PosixAlpha Alpha Alphabetic characters
+ ascii ASCII Any ASCII character
+ blank PosixBlank Blank \h Horizontal whitespace;
+ full-range also written
+ as \p{HorizSpace} (GNU
+ extension)
+ cntrl PosixCntrl Cntrl Control characters
+ digit PosixDigit Digit \d Decimal digits
+ graph PosixGraph Graph Alnum plus Punct
+ lower PosixLower Lower Lowercase characters
+ print PosixPrint Print Graph plus Print, but not
+ any Cntrls
+ punct PosixPunct Punct These aren't precisely
+ equivalent. See NOTE,
+ below.
+ space PosixSpace Space [\s\cK] Whitespace
+ PerlSpace SpacePerl \s Perl's whitespace
+ definition
+ upper PosixUpper Upper Uppercase characters
+ word PerlWord Word \w Alnum plus '_' (Perl
+ extension)
+ xdigit ASCII_Hex_Digit XDigit Hexadecimal digit,
+ ASCII-range is
+ [0-9A-Fa-f]
+
+NOTE on C<[[:punct:]]>, C<\p{PosixPunct}> and C<\p{Punct}>:
+In the ASCII range, C<[[:punct:]]> and C<\p{PosixPunct}> match
+C<[-!"#$%&'()*+,./:;<=E<gt>?@[\\\]^_`{|}~]> (although if a locale is in
+effect, it could alter the behavior of C<[[:punct:]]>); and C<\p{Punct}>
+matches C<[-!"#%&'()*,./:;?@[\\\]_{}]>. When matching a UTF-8 string,
+C<[[:punct:]]> matches what it does in the ASCII range, plus what
+C<\p{Punct}> matches. C<\p{Punct}> matches, anything that isn't a
+control, an alphanumeric, a space, nor a symbol.
+
+Within a character class:
+
+ POSIX traditional Unicode
+ [:digit:] \d \p{Digit}
+ [:^digit:] \D \P{Digit}
+
+=head2 ANCHORS
+
+All are zero-width assertions.
+
+ ^ Match string start (or line, if /m is used)
+ $ Match string end (or line, if /m is used) or before newline
+ \b Match word boundary (between \w and \W)
+ \B Match except at word boundary (between \w and \w or \W and \W)
+ \A Match string start (regardless of /m)
+ \Z Match string end (before optional newline)
+ \z Match absolute string end
+ \G Match where previous m//g left off
+ \K Keep the stuff left of the \K, don't include it in $&
+
+=head2 QUANTIFIERS
+
+Quantifiers are greedy by default and match the B<longest> leftmost.
+
+ Maximal Minimal Possessive Allowed range
+ ------- ------- ---------- -------------
+ {n,m} {n,m}? {n,m}+ Must occur at least n times
+ but no more than m times
+ {n,} {n,}? {n,}+ Must occur at least n times
+ {n} {n}? {n}+ Must occur exactly n times
+ * *? *+ 0 or more times (same as {0,})
+ + +? ++ 1 or more times (same as {1,})
+ ? ?? ?+ 0 or 1 time (same as {0,1})
+
+The possessive forms (new in Perl 5.10) prevent backtracking: what gets
+matched by a pattern with a possessive quantifier will not be backtracked
+into, even if that causes the whole match to fail.
+
+There is no quantifier C<{,n}>. That's interpreted as a literal string.
+
+=head2 EXTENDED CONSTRUCTS
+
+ (?#text) A comment
+ (?:...) Groups subexpressions without capturing (cluster)
+ (?pimsx-imsx:...) Enable/disable option (as per m// modifiers)
+ (?=...) Zero-width positive lookahead assertion
+ (?!...) Zero-width negative lookahead assertion
+ (?<=...) Zero-width positive lookbehind assertion
+ (?<!...) Zero-width negative lookbehind assertion
+ (?>...) Grab what we can, prohibit backtracking
+ (?|...) Branch reset
+ (?<name>...) Named capture
+ (?'name'...) Named capture
+ (?P<name>...) Named capture (python syntax)
+ (?{ code }) Embedded code, return value becomes $^R
+ (??{ code }) Dynamic regex, return value used as regex
+ (?N) Recurse into subpattern number N
+ (?-N), (?+N) Recurse into Nth previous/next subpattern
+ (?R), (?0) Recurse at the beginning of the whole pattern
+ (?&name) Recurse into a named subpattern
+ (?P>name) Recurse into a named subpattern (python syntax)
+ (?(cond)yes|no)
+ (?(cond)yes) Conditional expression, where "cond" can be:
+ (N) subpattern N has matched something
+ (<name>) named subpattern has matched something
+ ('name') named subpattern has matched something
+ (?{code}) code condition
+ (R) true if recursing
+ (RN) true if recursing into Nth subpattern
+ (R&name) true if recursing into named subpattern
+ (DEFINE) always false, no no-pattern allowed
+
+=head2 VARIABLES
+
+ $_ Default variable for operators to use
+
+ $` Everything prior to matched string
+ $& Entire matched string
+ $' Everything after to matched string
+
+ ${^PREMATCH} Everything prior to matched string
+ ${^MATCH} Entire matched string
+ ${^POSTMATCH} Everything after to matched string
+
+The use of C<$`>, C<$&> or C<$'> will slow down B<all> regex use
+within your program. Consult L<perlvar> for C<@->
+to see equivalent expressions that won't cause slow down.
+See also L<Devel::SawAmpersand>. Starting with Perl 5.10, you
+can also use the equivalent variables C<${^PREMATCH}>, C<${^MATCH}>
+and C<${^POSTMATCH}>, but for them to be defined, you have to
+specify the C</p> (preserve) modifier on your regular expression.
+
+ $1, $2 ... hold the Xth captured expr
+ $+ Last parenthesized pattern match
+ $^N Holds the most recently closed capture
+ $^R Holds the result of the last (?{...}) expr
+ @- Offsets of starts of groups. $-[0] holds start of whole match
+ @+ Offsets of ends of groups. $+[0] holds end of whole match
+ %+ Named capture buffers
+ %- Named capture buffers, as array refs
+
+Captured groups are numbered according to their I<opening> paren.
+
+=head2 FUNCTIONS
+
+ lc Lowercase a string
+ lcfirst Lowercase first char of a string
+ uc Uppercase a string
+ ucfirst Titlecase first char of a string
+
+ pos Return or set current match position
+ quotemeta Quote metacharacters
+ reset Reset ?pattern? status
+ study Analyze string for optimizing matching
+
+ split Use a regex to split a string into parts
+
+The first four of these are like the escape sequences C<\L>, C<\l>,
+C<\U>, and C<\u>. For Titlecase, see L</Titlecase>.
+
+=head2 TERMINOLOGY
+
+=head3 Titlecase
+
+Unicode concept which most often is equal to uppercase, but for
+certain characters like the German "sharp s" there is a difference.
+
+=head1 AUTHOR
+
+Iain Truskett. Updated by the Perl 5 Porters.
+
+This document may be distributed under the same terms as Perl itself.
+
+=head1 SEE ALSO
+
+=over 4
+
+=item *
+
+L<perlretut> for a tutorial on regular expressions.
+
+=item *
+
+L<perlrequick> for a rapid tutorial.
+
+=item *
+
+L<perlre> for more details.
+
+=item *
+
+L<perlvar> for details on the variables.
+
+=item *
+
+L<perlop> for details on the operators.
+
+=item *
+
+L<perlfunc> for details on the functions.
+
+=item *
+
+L<perlfaq6> for FAQs on regular expressions.
+
+=item *
+
+L<perlrebackslash> for a reference on backslash sequences.
+
+=item *
+
+L<perlrecharclass> for a reference on character classes.
+
+=item *
+
+The L<re> module to alter behaviour and aid
+debugging.
+
+=item *
+
+L<perldebug/"Debugging regular expressions">
+
+=item *
+
+L<perluniintro>, L<perlunicode>, L<charnames> and L<perllocale>
+for details on regexes and internationalisation.
+
+=item *
+
+I<Mastering Regular Expressions> by Jeffrey Friedl
+(F<http://oreilly.com/catalog/9780596528126/>) for a thorough grounding and
+reference on the topic.
+
+=back
+
+=head1 THANKS
+
+David P.C. Wollmann,
+Richard Soderberg,
+Sean M. Burke,
+Tom Christiansen,
+Jim Cromie,
+and
+Jeffrey Goff
+for useful advice.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlretut.pod b/Master/tlpkg/tlperl/lib/pods/perlretut.pod
new file mode 100644
index 00000000000..0ff743838c4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlretut.pod
@@ -0,0 +1,2879 @@
+=head1 NAME
+
+perlretut - Perl regular expressions tutorial
+
+=head1 DESCRIPTION
+
+This page provides a basic tutorial on understanding, creating and
+using regular expressions in Perl. It serves as a complement to the
+reference page on regular expressions L<perlre>. Regular expressions
+are an integral part of the C<m//>, C<s///>, C<qr//> and C<split>
+operators and so this tutorial also overlaps with
+L<perlop/"Regexp Quote-Like Operators"> and L<perlfunc/split>.
+
+Perl is widely renowned for excellence in text processing, and regular
+expressions are one of the big factors behind this fame. Perl regular
+expressions display an efficiency and flexibility unknown in most
+other computer languages. Mastering even the basics of regular
+expressions will allow you to manipulate text with surprising ease.
+
+What is a regular expression? A regular expression is simply a string
+that describes a pattern. Patterns are in common use these days;
+examples are the patterns typed into a search engine to find web pages
+and the patterns used to list files in a directory, e.g., C<ls *.txt>
+or C<dir *.*>. In Perl, the patterns described by regular expressions
+are used to search strings, extract desired parts of strings, and to
+do search and replace operations.
+
+Regular expressions have the undeserved reputation of being abstract
+and difficult to understand. Regular expressions are constructed using
+simple concepts like conditionals and loops and are no more difficult
+to understand than the corresponding C<if> conditionals and C<while>
+loops in the Perl language itself. In fact, the main challenge in
+learning regular expressions is just getting used to the terse
+notation used to express these concepts.
+
+This tutorial flattens the learning curve by discussing regular
+expression concepts, along with their notation, one at a time and with
+many examples. The first part of the tutorial will progress from the
+simplest word searches to the basic regular expression concepts. If
+you master the first part, you will have all the tools needed to solve
+about 98% of your needs. The second part of the tutorial is for those
+comfortable with the basics and hungry for more power tools. It
+discusses the more advanced regular expression operators and
+introduces the latest cutting edge innovations in 5.6.0.
+
+A note: to save time, 'regular expression' is often abbreviated as
+regexp or regex. Regexp is a more natural abbreviation than regex, but
+is harder to pronounce. The Perl pod documentation is evenly split on
+regexp vs regex; in Perl, there is more than one way to abbreviate it.
+We'll use regexp in this tutorial.
+
+=head1 Part 1: The basics
+
+=head2 Simple word matching
+
+The simplest regexp is simply a word, or more generally, a string of
+characters. A regexp consisting of a word matches any string that
+contains that word:
+
+ "Hello World" =~ /World/; # matches
+
+What is this Perl statement all about? C<"Hello World"> is a simple
+double quoted string. C<World> is the regular expression and the
+C<//> enclosing C</World/> tells Perl to search a string for a match.
+The operator C<=~> associates the string with the regexp match and
+produces a true value if the regexp matched, or false if the regexp
+did not match. In our case, C<World> matches the second word in
+C<"Hello World">, so the expression is true. Expressions like this
+are useful in conditionals:
+
+ if ("Hello World" =~ /World/) {
+ print "It matches\n";
+ }
+ else {
+ print "It doesn't match\n";
+ }
+
+There are useful variations on this theme. The sense of the match can
+be reversed by using the C<!~> operator:
+
+ if ("Hello World" !~ /World/) {
+ print "It doesn't match\n";
+ }
+ else {
+ print "It matches\n";
+ }
+
+The literal string in the regexp can be replaced by a variable:
+
+ $greeting = "World";
+ if ("Hello World" =~ /$greeting/) {
+ print "It matches\n";
+ }
+ else {
+ print "It doesn't match\n";
+ }
+
+If you're matching against the special default variable C<$_>, the
+C<$_ =~> part can be omitted:
+
+ $_ = "Hello World";
+ if (/World/) {
+ print "It matches\n";
+ }
+ else {
+ print "It doesn't match\n";
+ }
+
+And finally, the C<//> default delimiters for a match can be changed
+to arbitrary delimiters by putting an C<'m'> out front:
+
+ "Hello World" =~ m!World!; # matches, delimited by '!'
+ "Hello World" =~ m{World}; # matches, note the matching '{}'
+ "/usr/bin/perl" =~ m"/perl"; # matches after '/usr/bin',
+ # '/' becomes an ordinary char
+
+C</World/>, C<m!World!>, and C<m{World}> all represent the
+same thing. When, e.g., the quote (C<">) is used as a delimiter, the forward
+slash C<'/'> becomes an ordinary character and can be used in this regexp
+without trouble.
+
+Let's consider how different regexps would match C<"Hello World">:
+
+ "Hello World" =~ /world/; # doesn't match
+ "Hello World" =~ /o W/; # matches
+ "Hello World" =~ /oW/; # doesn't match
+ "Hello World" =~ /World /; # doesn't match
+
+The first regexp C<world> doesn't match because regexps are
+case-sensitive. The second regexp matches because the substring
+S<C<'o W'>> occurs in the string S<C<"Hello World">>. The space
+character ' ' is treated like any other character in a regexp and is
+needed to match in this case. The lack of a space character is the
+reason the third regexp C<'oW'> doesn't match. The fourth regexp
+C<'World '> doesn't match because there is a space at the end of the
+regexp, but not at the end of the string. The lesson here is that
+regexps must match a part of the string I<exactly> in order for the
+statement to be true.
+
+If a regexp matches in more than one place in the string, Perl will
+always match at the earliest possible point in the string:
+
+ "Hello World" =~ /o/; # matches 'o' in 'Hello'
+ "That hat is red" =~ /hat/; # matches 'hat' in 'That'
+
+With respect to character matching, there are a few more points you
+need to know about. First of all, not all characters can be used 'as
+is' in a match. Some characters, called I<metacharacters>, are reserved
+for use in regexp notation. The metacharacters are
+
+ {}[]()^$.|*+?\
+
+The significance of each of these will be explained
+in the rest of the tutorial, but for now, it is important only to know
+that a metacharacter can be matched by putting a backslash before it:
+
+ "2+2=4" =~ /2+2/; # doesn't match, + is a metacharacter
+ "2+2=4" =~ /2\+2/; # matches, \+ is treated like an ordinary +
+ "The interval is [0,1)." =~ /[0,1)./ # is a syntax error!
+ "The interval is [0,1)." =~ /\[0,1\)\./ # matches
+ "#!/usr/bin/perl" =~ /#!\/usr\/bin\/perl/; # matches
+
+In the last regexp, the forward slash C<'/'> is also backslashed,
+because it is used to delimit the regexp. This can lead to LTS
+(leaning toothpick syndrome), however, and it is often more readable
+to change delimiters.
+
+ "#!/usr/bin/perl" =~ m!#\!/usr/bin/perl!; # easier to read
+
+The backslash character C<'\'> is a metacharacter itself and needs to
+be backslashed:
+
+ 'C:\WIN32' =~ /C:\\WIN/; # matches
+
+In addition to the metacharacters, there are some ASCII characters
+which don't have printable character equivalents and are instead
+represented by I<escape sequences>. Common examples are C<\t> for a
+tab, C<\n> for a newline, C<\r> for a carriage return and C<\a> for a
+bell. If your string is better thought of as a sequence of arbitrary
+bytes, the octal escape sequence, e.g., C<\033>, or hexadecimal escape
+sequence, e.g., C<\x1B> may be a more natural representation for your
+bytes. Here are some examples of escapes:
+
+ "1000\t2000" =~ m(0\t2) # matches
+ "1000\n2000" =~ /0\n20/ # matches
+ "1000\t2000" =~ /\000\t2/ # doesn't match, "0" ne "\000"
+ "cat" =~ /\143\x61\x74/ # matches in ASCII, but a weird way to spell cat
+
+If you've been around Perl a while, all this talk of escape sequences
+may seem familiar. Similar escape sequences are used in double-quoted
+strings and in fact the regexps in Perl are mostly treated as
+double-quoted strings. This means that variables can be used in
+regexps as well. Just like double-quoted strings, the values of the
+variables in the regexp will be substituted in before the regexp is
+evaluated for matching purposes. So we have:
+
+ $foo = 'house';
+ 'housecat' =~ /$foo/; # matches
+ 'cathouse' =~ /cat$foo/; # matches
+ 'housecat' =~ /${foo}cat/; # matches
+
+So far, so good. With the knowledge above you can already perform
+searches with just about any literal string regexp you can dream up.
+Here is a I<very simple> emulation of the Unix grep program:
+
+ % cat > simple_grep
+ #!/usr/bin/perl
+ $regexp = shift;
+ while (<>) {
+ print if /$regexp/;
+ }
+ ^D
+
+ % chmod +x simple_grep
+
+ % simple_grep abba /usr/dict/words
+ Babbage
+ cabbage
+ cabbages
+ sabbath
+ Sabbathize
+ Sabbathizes
+ sabbatical
+ scabbard
+ scabbards
+
+This program is easy to understand. C<#!/usr/bin/perl> is the standard
+way to invoke a perl program from the shell.
+S<C<$regexp = shift;>> saves the first command line argument as the
+regexp to be used, leaving the rest of the command line arguments to
+be treated as files. S<C<< while (<>) >>> loops over all the lines in
+all the files. For each line, S<C<print if /$regexp/;>> prints the
+line if the regexp matches the line. In this line, both C<print> and
+C</$regexp/> use the default variable C<$_> implicitly.
+
+With all of the regexps above, if the regexp matched anywhere in the
+string, it was considered a match. Sometimes, however, we'd like to
+specify I<where> in the string the regexp should try to match. To do
+this, we would use the I<anchor> metacharacters C<^> and C<$>. The
+anchor C<^> means match at the beginning of the string and the anchor
+C<$> means match at the end of the string, or before a newline at the
+end of the string. Here is how they are used:
+
+ "housekeeper" =~ /keeper/; # matches
+ "housekeeper" =~ /^keeper/; # doesn't match
+ "housekeeper" =~ /keeper$/; # matches
+ "housekeeper\n" =~ /keeper$/; # matches
+
+The second regexp doesn't match because C<^> constrains C<keeper> to
+match only at the beginning of the string, but C<"housekeeper"> has
+keeper starting in the middle. The third regexp does match, since the
+C<$> constrains C<keeper> to match only at the end of the string.
+
+When both C<^> and C<$> are used at the same time, the regexp has to
+match both the beginning and the end of the string, i.e., the regexp
+matches the whole string. Consider
+
+ "keeper" =~ /^keep$/; # doesn't match
+ "keeper" =~ /^keeper$/; # matches
+ "" =~ /^$/; # ^$ matches an empty string
+
+The first regexp doesn't match because the string has more to it than
+C<keep>. Since the second regexp is exactly the string, it
+matches. Using both C<^> and C<$> in a regexp forces the complete
+string to match, so it gives you complete control over which strings
+match and which don't. Suppose you are looking for a fellow named
+bert, off in a string by himself:
+
+ "dogbert" =~ /bert/; # matches, but not what you want
+
+ "dilbert" =~ /^bert/; # doesn't match, but ..
+ "bertram" =~ /^bert/; # matches, so still not good enough
+
+ "bertram" =~ /^bert$/; # doesn't match, good
+ "dilbert" =~ /^bert$/; # doesn't match, good
+ "bert" =~ /^bert$/; # matches, perfect
+
+Of course, in the case of a literal string, one could just as easily
+use the string comparison S<C<$string eq 'bert'>> and it would be
+more efficient. The C<^...$> regexp really becomes useful when we
+add in the more powerful regexp tools below.
+
+=head2 Using character classes
+
+Although one can already do quite a lot with the literal string
+regexps above, we've only scratched the surface of regular expression
+technology. In this and subsequent sections we will introduce regexp
+concepts (and associated metacharacter notations) that will allow a
+regexp to not just represent a single character sequence, but a I<whole
+class> of them.
+
+One such concept is that of a I<character class>. A character class
+allows a set of possible characters, rather than just a single
+character, to match at a particular point in a regexp. Character
+classes are denoted by brackets C<[...]>, with the set of characters
+to be possibly matched inside. Here are some examples:
+
+ /cat/; # matches 'cat'
+ /[bcr]at/; # matches 'bat, 'cat', or 'rat'
+ /item[0123456789]/; # matches 'item0' or ... or 'item9'
+ "abc" =~ /[cab]/; # matches 'a'
+
+In the last statement, even though C<'c'> is the first character in
+the class, C<'a'> matches because the first character position in the
+string is the earliest point at which the regexp can match.
+
+ /[yY][eE][sS]/; # match 'yes' in a case-insensitive way
+ # 'yes', 'Yes', 'YES', etc.
+
+This regexp displays a common task: perform a case-insensitive
+match. Perl provides a way of avoiding all those brackets by simply
+appending an C<'i'> to the end of the match. Then C</[yY][eE][sS]/;>
+can be rewritten as C</yes/i;>. The C<'i'> stands for
+case-insensitive and is an example of a I<modifier> of the matching
+operation. We will meet other modifiers later in the tutorial.
+
+We saw in the section above that there were ordinary characters, which
+represented themselves, and special characters, which needed a
+backslash C<\> to represent themselves. The same is true in a
+character class, but the sets of ordinary and special characters
+inside a character class are different than those outside a character
+class. The special characters for a character class are C<-]\^$> (and
+the pattern delimiter, whatever it is).
+C<]> is special because it denotes the end of a character class. C<$> is
+special because it denotes a scalar variable. C<\> is special because
+it is used in escape sequences, just like above. Here is how the
+special characters C<]$\> are handled:
+
+ /[\]c]def/; # matches ']def' or 'cdef'
+ $x = 'bcr';
+ /[$x]at/; # matches 'bat', 'cat', or 'rat'
+ /[\$x]at/; # matches '$at' or 'xat'
+ /[\\$x]at/; # matches '\at', 'bat, 'cat', or 'rat'
+
+The last two are a little tricky. In C<[\$x]>, the backslash protects
+the dollar sign, so the character class has two members C<$> and C<x>.
+In C<[\\$x]>, the backslash is protected, so C<$x> is treated as a
+variable and substituted in double quote fashion.
+
+The special character C<'-'> acts as a range operator within character
+classes, so that a contiguous set of characters can be written as a
+range. With ranges, the unwieldy C<[0123456789]> and C<[abc...xyz]>
+become the svelte C<[0-9]> and C<[a-z]>. Some examples are
+
+ /item[0-9]/; # matches 'item0' or ... or 'item9'
+ /[0-9bx-z]aa/; # matches '0aa', ..., '9aa',
+ # 'baa', 'xaa', 'yaa', or 'zaa'
+ /[0-9a-fA-F]/; # matches a hexadecimal digit
+ /[0-9a-zA-Z_]/; # matches a "word" character,
+ # like those in a Perl variable name
+
+If C<'-'> is the first or last character in a character class, it is
+treated as an ordinary character; C<[-ab]>, C<[ab-]> and C<[a\-b]> are
+all equivalent.
+
+The special character C<^> in the first position of a character class
+denotes a I<negated character class>, which matches any character but
+those in the brackets. Both C<[...]> and C<[^...]> must match a
+character, or the match fails. Then
+
+ /[^a]at/; # doesn't match 'aat' or 'at', but matches
+ # all other 'bat', 'cat, '0at', '%at', etc.
+ /[^0-9]/; # matches a non-numeric character
+ /[a^]at/; # matches 'aat' or '^at'; here '^' is ordinary
+
+Now, even C<[0-9]> can be a bother to write multiple times, so in the
+interest of saving keystrokes and making regexps more readable, Perl
+has several abbreviations for common character classes, as shown below.
+Since the introduction of Unicode, these character classes match more
+than just a few characters in the ISO 8859-1 range.
+
+=over 4
+
+=item *
+
+\d matches a digit, not just [0-9] but also digits from non-roman scripts
+
+=item *
+
+\s matches a whitespace character, the set [\ \t\r\n\f] and others
+
+=item *
+
+\w matches a word character (alphanumeric or _), not just [0-9a-zA-Z_]
+but also digits and characters from non-roman scripts
+
+=item *
+
+\D is a negated \d; it represents any other character than a digit, or [^\d]
+
+=item *
+
+\S is a negated \s; it represents any non-whitespace character [^\s]
+
+=item *
+
+\W is a negated \w; it represents any non-word character [^\w]
+
+=item *
+
+The period '.' matches any character but "\n" (unless the modifier C<//s> is
+in effect, as explained below).
+
+=back
+
+The C<\d\s\w\D\S\W> abbreviations can be used both inside and outside
+of character classes. Here are some in use:
+
+ /\d\d:\d\d:\d\d/; # matches a hh:mm:ss time format
+ /[\d\s]/; # matches any digit or whitespace character
+ /\w\W\w/; # matches a word char, followed by a
+ # non-word char, followed by a word char
+ /..rt/; # matches any two chars, followed by 'rt'
+ /end\./; # matches 'end.'
+ /end[.]/; # same thing, matches 'end.'
+
+Because a period is a metacharacter, it needs to be escaped to match
+as an ordinary period. Because, for example, C<\d> and C<\w> are sets
+of characters, it is incorrect to think of C<[^\d\w]> as C<[\D\W]>; in
+fact C<[^\d\w]> is the same as C<[^\w]>, which is the same as
+C<[\W]>. Think DeMorgan's laws.
+
+An anchor useful in basic regexps is the I<word anchor>
+C<\b>. This matches a boundary between a word character and a non-word
+character C<\w\W> or C<\W\w>:
+
+ $x = "Housecat catenates house and cat";
+ $x =~ /cat/; # matches cat in 'housecat'
+ $x =~ /\bcat/; # matches cat in 'catenates'
+ $x =~ /cat\b/; # matches cat in 'housecat'
+ $x =~ /\bcat\b/; # matches 'cat' at end of string
+
+Note in the last example, the end of the string is considered a word
+boundary.
+
+You might wonder why C<'.'> matches everything but C<"\n"> - why not
+every character? The reason is that often one is matching against
+lines and would like to ignore the newline characters. For instance,
+while the string C<"\n"> represents one line, we would like to think
+of it as empty. Then
+
+ "" =~ /^$/; # matches
+ "\n" =~ /^$/; # matches, $ anchors before "\n"
+
+ "" =~ /./; # doesn't match; it needs a char
+ "" =~ /^.$/; # doesn't match; it needs a char
+ "\n" =~ /^.$/; # doesn't match; it needs a char other than "\n"
+ "a" =~ /^.$/; # matches
+ "a\n" =~ /^.$/; # matches, $ anchors before "\n"
+
+This behavior is convenient, because we usually want to ignore
+newlines when we count and match characters in a line. Sometimes,
+however, we want to keep track of newlines. We might even want C<^>
+and C<$> to anchor at the beginning and end of lines within the
+string, rather than just the beginning and end of the string. Perl
+allows us to choose between ignoring and paying attention to newlines
+by using the C<//s> and C<//m> modifiers. C<//s> and C<//m> stand for
+single line and multi-line and they determine whether a string is to
+be treated as one continuous string, or as a set of lines. The two
+modifiers affect two aspects of how the regexp is interpreted: 1) how
+the C<'.'> character class is defined, and 2) where the anchors C<^>
+and C<$> are able to match. Here are the four possible combinations:
+
+=over 4
+
+=item *
+
+no modifiers (//): Default behavior. C<'.'> matches any character
+except C<"\n">. C<^> matches only at the beginning of the string and
+C<$> matches only at the end or before a newline at the end.
+
+=item *
+
+s modifier (//s): Treat string as a single long line. C<'.'> matches
+any character, even C<"\n">. C<^> matches only at the beginning of
+the string and C<$> matches only at the end or before a newline at the
+end.
+
+=item *
+
+m modifier (//m): Treat string as a set of multiple lines. C<'.'>
+matches any character except C<"\n">. C<^> and C<$> are able to match
+at the start or end of I<any> line within the string.
+
+=item *
+
+both s and m modifiers (//sm): Treat string as a single long line, but
+detect multiple lines. C<'.'> matches any character, even
+C<"\n">. C<^> and C<$>, however, are able to match at the start or end
+of I<any> line within the string.
+
+=back
+
+Here are examples of C<//s> and C<//m> in action:
+
+ $x = "There once was a girl\nWho programmed in Perl\n";
+
+ $x =~ /^Who/; # doesn't match, "Who" not at start of string
+ $x =~ /^Who/s; # doesn't match, "Who" not at start of string
+ $x =~ /^Who/m; # matches, "Who" at start of second line
+ $x =~ /^Who/sm; # matches, "Who" at start of second line
+
+ $x =~ /girl.Who/; # doesn't match, "." doesn't match "\n"
+ $x =~ /girl.Who/s; # matches, "." matches "\n"
+ $x =~ /girl.Who/m; # doesn't match, "." doesn't match "\n"
+ $x =~ /girl.Who/sm; # matches, "." matches "\n"
+
+Most of the time, the default behavior is what is wanted, but C<//s> and
+C<//m> are occasionally very useful. If C<//m> is being used, the start
+of the string can still be matched with C<\A> and the end of the string
+can still be matched with the anchors C<\Z> (matches both the end and
+the newline before, like C<$>), and C<\z> (matches only the end):
+
+ $x =~ /^Who/m; # matches, "Who" at start of second line
+ $x =~ /\AWho/m; # doesn't match, "Who" is not at start of string
+
+ $x =~ /girl$/m; # matches, "girl" at end of first line
+ $x =~ /girl\Z/m; # doesn't match, "girl" is not at end of string
+
+ $x =~ /Perl\Z/m; # matches, "Perl" is at newline before end
+ $x =~ /Perl\z/m; # doesn't match, "Perl" is not at end of string
+
+We now know how to create choices among classes of characters in a
+regexp. What about choices among words or character strings? Such
+choices are described in the next section.
+
+=head2 Matching this or that
+
+Sometimes we would like our regexp to be able to match different
+possible words or character strings. This is accomplished by using
+the I<alternation> metacharacter C<|>. To match C<dog> or C<cat>, we
+form the regexp C<dog|cat>. As before, Perl will try to match the
+regexp at the earliest possible point in the string. At each
+character position, Perl will first try to match the first
+alternative, C<dog>. If C<dog> doesn't match, Perl will then try the
+next alternative, C<cat>. If C<cat> doesn't match either, then the
+match fails and Perl moves to the next position in the string. Some
+examples:
+
+ "cats and dogs" =~ /cat|dog|bird/; # matches "cat"
+ "cats and dogs" =~ /dog|cat|bird/; # matches "cat"
+
+Even though C<dog> is the first alternative in the second regexp,
+C<cat> is able to match earlier in the string.
+
+ "cats" =~ /c|ca|cat|cats/; # matches "c"
+ "cats" =~ /cats|cat|ca|c/; # matches "cats"
+
+Here, all the alternatives match at the first string position, so the
+first alternative is the one that matches. If some of the
+alternatives are truncations of the others, put the longest ones first
+to give them a chance to match.
+
+ "cab" =~ /a|b|c/ # matches "c"
+ # /a|b|c/ == /[abc]/
+
+The last example points out that character classes are like
+alternations of characters. At a given character position, the first
+alternative that allows the regexp match to succeed will be the one
+that matches.
+
+=head2 Grouping things and hierarchical matching
+
+Alternation allows a regexp to choose among alternatives, but by
+itself it is unsatisfying. The reason is that each alternative is a whole
+regexp, but sometime we want alternatives for just part of a
+regexp. For instance, suppose we want to search for housecats or
+housekeepers. The regexp C<housecat|housekeeper> fits the bill, but is
+inefficient because we had to type C<house> twice. It would be nice to
+have parts of the regexp be constant, like C<house>, and some
+parts have alternatives, like C<cat|keeper>.
+
+The I<grouping> metacharacters C<()> solve this problem. Grouping
+allows parts of a regexp to be treated as a single unit. Parts of a
+regexp are grouped by enclosing them in parentheses. Thus we could solve
+the C<housecat|housekeeper> by forming the regexp as
+C<house(cat|keeper)>. The regexp C<house(cat|keeper)> means match
+C<house> followed by either C<cat> or C<keeper>. Some more examples
+are
+
+ /(a|b)b/; # matches 'ab' or 'bb'
+ /(ac|b)b/; # matches 'acb' or 'bb'
+ /(^a|b)c/; # matches 'ac' at start of string or 'bc' anywhere
+ /(a|[bc])d/; # matches 'ad', 'bd', or 'cd'
+
+ /house(cat|)/; # matches either 'housecat' or 'house'
+ /house(cat(s|)|)/; # matches either 'housecats' or 'housecat' or
+ # 'house'. Note groups can be nested.
+
+ /(19|20|)\d\d/; # match years 19xx, 20xx, or the Y2K problem, xx
+ "20" =~ /(19|20|)\d\d/; # matches the null alternative '()\d\d',
+ # because '20\d\d' can't match
+
+Alternations behave the same way in groups as out of them: at a given
+string position, the leftmost alternative that allows the regexp to
+match is taken. So in the last example at the first string position,
+C<"20"> matches the second alternative, but there is nothing left over
+to match the next two digits C<\d\d>. So Perl moves on to the next
+alternative, which is the null alternative and that works, since
+C<"20"> is two digits.
+
+The process of trying one alternative, seeing if it matches, and
+moving on to the next alternative, while going back in the string
+from where the previous alternative was tried, if it doesn't, is called
+I<backtracking>. The term 'backtracking' comes from the idea that
+matching a regexp is like a walk in the woods. Successfully matching
+a regexp is like arriving at a destination. There are many possible
+trailheads, one for each string position, and each one is tried in
+order, left to right. From each trailhead there may be many paths,
+some of which get you there, and some which are dead ends. When you
+walk along a trail and hit a dead end, you have to backtrack along the
+trail to an earlier point to try another trail. If you hit your
+destination, you stop immediately and forget about trying all the
+other trails. You are persistent, and only if you have tried all the
+trails from all the trailheads and not arrived at your destination, do
+you declare failure. To be concrete, here is a step-by-step analysis
+of what Perl does when it tries to match the regexp
+
+ "abcde" =~ /(abd|abc)(df|d|de)/;
+
+=over 4
+
+=item 0
+
+Start with the first letter in the string 'a'.
+
+=item 1
+
+Try the first alternative in the first group 'abd'.
+
+=item 2
+
+Match 'a' followed by 'b'. So far so good.
+
+=item 3
+
+'d' in the regexp doesn't match 'c' in the string - a dead
+end. So backtrack two characters and pick the second alternative in
+the first group 'abc'.
+
+=item 4
+
+Match 'a' followed by 'b' followed by 'c'. We are on a roll
+and have satisfied the first group. Set $1 to 'abc'.
+
+=item 5
+
+Move on to the second group and pick the first alternative
+'df'.
+
+=item 6
+
+Match the 'd'.
+
+=item 7
+
+'f' in the regexp doesn't match 'e' in the string, so a dead
+end. Backtrack one character and pick the second alternative in the
+second group 'd'.
+
+=item 8
+
+'d' matches. The second grouping is satisfied, so set $2 to
+'d'.
+
+=item 9
+
+We are at the end of the regexp, so we are done! We have
+matched 'abcd' out of the string "abcde".
+
+=back
+
+There are a couple of things to note about this analysis. First, the
+third alternative in the second group 'de' also allows a match, but we
+stopped before we got to it - at a given character position, leftmost
+wins. Second, we were able to get a match at the first character
+position of the string 'a'. If there were no matches at the first
+position, Perl would move to the second character position 'b' and
+attempt the match all over again. Only when all possible paths at all
+possible character positions have been exhausted does Perl give
+up and declare S<C<$string =~ /(abd|abc)(df|d|de)/;>> to be false.
+
+Even with all this work, regexp matching happens remarkably fast. To
+speed things up, Perl compiles the regexp into a compact sequence of
+opcodes that can often fit inside a processor cache. When the code is
+executed, these opcodes can then run at full throttle and search very
+quickly.
+
+=head2 Extracting matches
+
+The grouping metacharacters C<()> also serve another completely
+different function: they allow the extraction of the parts of a string
+that matched. This is very useful to find out what matched and for
+text processing in general. For each grouping, the part that matched
+inside goes into the special variables C<$1>, C<$2>, etc. They can be
+used just as ordinary variables:
+
+ # extract hours, minutes, seconds
+ if ($time =~ /(\d\d):(\d\d):(\d\d)/) { # match hh:mm:ss format
+ $hours = $1;
+ $minutes = $2;
+ $seconds = $3;
+ }
+
+Now, we know that in scalar context,
+S<C<$time =~ /(\d\d):(\d\d):(\d\d)/>> returns a true or false
+value. In list context, however, it returns the list of matched values
+C<($1,$2,$3)>. So we could write the code more compactly as
+
+ # extract hours, minutes, seconds
+ ($hours, $minutes, $second) = ($time =~ /(\d\d):(\d\d):(\d\d)/);
+
+If the groupings in a regexp are nested, C<$1> gets the group with the
+leftmost opening parenthesis, C<$2> the next opening parenthesis,
+etc. Here is a regexp with nested groups:
+
+ /(ab(cd|ef)((gi)|j))/;
+ 1 2 34
+
+If this regexp matches, C<$1> contains a string starting with
+C<'ab'>, C<$2> is either set to C<'cd'> or C<'ef'>, C<$3> equals either
+C<'gi'> or C<'j'>, and C<$4> is either set to C<'gi'>, just like C<$3>,
+or it remains undefined.
+
+For convenience, Perl sets C<$+> to the string held by the highest numbered
+C<$1>, C<$2>,... that got assigned (and, somewhat related, C<$^N> to the
+value of the C<$1>, C<$2>,... most-recently assigned; i.e. the C<$1>,
+C<$2>,... associated with the rightmost closing parenthesis used in the
+match).
+
+
+=head2 Backreferences
+
+Closely associated with the matching variables C<$1>, C<$2>, ... are
+the I<backreferences> C<\1>, C<\2>,... Backreferences are simply
+matching variables that can be used I<inside> a regexp. This is a
+really nice feature; what matches later in a regexp is made to depend on
+what matched earlier in the regexp. Suppose we wanted to look
+for doubled words in a text, like 'the the'. The following regexp finds
+all 3-letter doubles with a space in between:
+
+ /\b(\w\w\w)\s\1\b/;
+
+The grouping assigns a value to \1, so that the same 3 letter sequence
+is used for both parts.
+
+A similar task is to find words consisting of two identical parts:
+
+ % simple_grep '^(\w\w\w\w|\w\w\w|\w\w|\w)\1$' /usr/dict/words
+ beriberi
+ booboo
+ coco
+ mama
+ murmur
+ papa
+
+The regexp has a single grouping which considers 4-letter
+combinations, then 3-letter combinations, etc., and uses C<\1> to look for
+a repeat. Although C<$1> and C<\1> represent the same thing, care should be
+taken to use matched variables C<$1>, C<$2>,... only I<outside> a regexp
+and backreferences C<\1>, C<\2>,... only I<inside> a regexp; not doing
+so may lead to surprising and unsatisfactory results.
+
+
+=head2 Relative backreferences
+
+Counting the opening parentheses to get the correct number for a
+backreference is errorprone as soon as there is more than one
+capturing group. A more convenient technique became available
+with Perl 5.10: relative backreferences. To refer to the immediately
+preceding capture group one now may write C<\g{-1}>, the next but
+last is available via C<\g{-2}>, and so on.
+
+Another good reason in addition to readability and maintainability
+for using relative backreferences is illustrated by the following example,
+where a simple pattern for matching peculiar strings is used:
+
+ $a99a = '([a-z])(\d)\2\1'; # matches a11a, g22g, x33x, etc.
+
+Now that we have this pattern stored as a handy string, we might feel
+tempted to use it as a part of some other pattern:
+
+ $line = "code=e99e";
+ if ($line =~ /^(\w+)=$a99a$/){ # unexpected behavior!
+ print "$1 is valid\n";
+ } else {
+ print "bad line: '$line'\n";
+ }
+
+But this doesn't match, at least not the way one might expect. Only
+after inserting the interpolated C<$a99a> and looking at the resulting
+full text of the regexp is it obvious that the backreferences have
+backfired. The subexpression C<(\w+)> has snatched number 1 and
+demoted the groups in C<$a99a> by one rank. This can be avoided by
+using relative backreferences:
+
+ $a99a = '([a-z])(\d)\g{-1}\g{-2}'; # safe for being interpolated
+
+
+=head2 Named backreferences
+
+Perl 5.10 also introduced named capture buffers and named backreferences.
+To attach a name to a capturing group, you write either
+C<< (?<name>...) >> or C<< (?'name'...) >>. The backreference may
+then be written as C<\g{name}>. It is permissible to attach the
+same name to more than one group, but then only the leftmost one of the
+eponymous set can be referenced. Outside of the pattern a named
+capture buffer is accessible through the C<%+> hash.
+
+Assuming that we have to match calendar dates which may be given in one
+of the three formats yyyy-mm-dd, mm/dd/yyyy or dd.mm.yyyy, we can write
+three suitable patterns where we use 'd', 'm' and 'y' respectively as the
+names of the buffers capturing the pertaining components of a date. The
+matching operation combines the three patterns as alternatives:
+
+ $fmt1 = '(?<y>\d\d\d\d)-(?<m>\d\d)-(?<d>\d\d)';
+ $fmt2 = '(?<m>\d\d)/(?<d>\d\d)/(?<y>\d\d\d\d)';
+ $fmt3 = '(?<d>\d\d)\.(?<m>\d\d)\.(?<y>\d\d\d\d)';
+ for my $d qw( 2006-10-21 15.01.2007 10/31/2005 ){
+ if ( $d =~ m{$fmt1|$fmt2|$fmt3} ){
+ print "day=$+{d} month=$+{m} year=$+{y}\n";
+ }
+ }
+
+If any of the alternatives matches, the hash C<%+> is bound to contain the
+three key-value pairs.
+
+
+=head2 Alternative capture group numbering
+
+Yet another capturing group numbering technique (also as from Perl 5.10)
+deals with the problem of referring to groups within a set of alternatives.
+Consider a pattern for matching a time of the day, civil or military style:
+
+ if ( $time =~ /(\d\d|\d):(\d\d)|(\d\d)(\d\d)/ ){
+ # process hour and minute
+ }
+
+Processing the results requires an additional if statement to determine
+whether C<$1> and C<$2> or C<$3> and C<$4> contain the goodies. It would
+be easier if we could use buffer numbers 1 and 2 in second alternative as
+well, and this is exactly what the parenthesized construct C<(?|...)>,
+set around an alternative achieves. Here is an extended version of the
+previous pattern:
+
+ if ( $time =~ /(?|(\d\d|\d):(\d\d)|(\d\d)(\d\d))\s+([A-Z][A-Z][A-Z])/ ){
+ print "hour=$1 minute=$2 zone=$3\n";
+ }
+
+Within the alternative numbering group, buffer numbers start at the same
+position for each alternative. After the group, numbering continues
+with one higher than the maximum reached across all the alternatives.
+
+=head2 Position information
+
+In addition to what was matched, Perl (since 5.6.0) also provides the
+positions of what was matched as contents of the C<@-> and C<@+>
+arrays. C<$-[0]> is the position of the start of the entire match and
+C<$+[0]> is the position of the end. Similarly, C<$-[n]> is the
+position of the start of the C<$n> match and C<$+[n]> is the position
+of the end. If C<$n> is undefined, so are C<$-[n]> and C<$+[n]>. Then
+this code
+
+ $x = "Mmm...donut, thought Homer";
+ $x =~ /^(Mmm|Yech)\.\.\.(donut|peas)/; # matches
+ foreach $expr (1..$#-) {
+ print "Match $expr: '${$expr}' at position ($-[$expr],$+[$expr])\n";
+ }
+
+prints
+
+ Match 1: 'Mmm' at position (0,3)
+ Match 2: 'donut' at position (6,11)
+
+Even if there are no groupings in a regexp, it is still possible to
+find out what exactly matched in a string. If you use them, Perl
+will set C<$`> to the part of the string before the match, will set C<$&>
+to the part of the string that matched, and will set C<$'> to the part
+of the string after the match. An example:
+
+ $x = "the cat caught the mouse";
+ $x =~ /cat/; # $` = 'the ', $& = 'cat', $' = ' caught the mouse'
+ $x =~ /the/; # $` = '', $& = 'the', $' = ' cat caught the mouse'
+
+In the second match, C<$`> equals C<''> because the regexp matched at the
+first character position in the string and stopped; it never saw the
+second 'the'. It is important to note that using C<$`> and C<$'>
+slows down regexp matching quite a bit, while C<$&> slows it down to a
+lesser extent, because if they are used in one regexp in a program,
+they are generated for I<all> regexps in the program. So if raw
+performance is a goal of your application, they should be avoided.
+If you need to extract the corresponding substrings, use C<@-> and
+C<@+> instead:
+
+ $` is the same as substr( $x, 0, $-[0] )
+ $& is the same as substr( $x, $-[0], $+[0]-$-[0] )
+ $' is the same as substr( $x, $+[0] )
+
+
+=head2 Non-capturing groupings
+
+A group that is required to bundle a set of alternatives may or may not be
+useful as a capturing group. If it isn't, it just creates a superfluous
+addition to the set of available capture buffer values, inside as well as
+outside the regexp. Non-capturing groupings, denoted by C<(?:regexp)>,
+still allow the regexp to be treated as a single unit, but don't establish
+a capturing buffer at the same time. Both capturing and non-capturing
+groupings are allowed to co-exist in the same regexp. Because there is
+no extraction, non-capturing groupings are faster than capturing
+groupings. Non-capturing groupings are also handy for choosing exactly
+which parts of a regexp are to be extracted to matching variables:
+
+ # match a number, $1-$4 are set, but we only want $1
+ /([+-]?\ *(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?)/;
+
+ # match a number faster , only $1 is set
+ /([+-]?\ *(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?)/;
+
+ # match a number, get $1 = whole number, $2 = exponent
+ /([+-]?\ *(?:\d+(?:\.\d*)?|\.\d+)(?:[eE]([+-]?\d+))?)/;
+
+Non-capturing groupings are also useful for removing nuisance
+elements gathered from a split operation where parentheses are
+required for some reason:
+
+ $x = '12aba34ba5';
+ @num = split /(a|b)+/, $x; # @num = ('12','a','34','b','5')
+ @num = split /(?:a|b)+/, $x; # @num = ('12','34','5')
+
+
+=head2 Matching repetitions
+
+The examples in the previous section display an annoying weakness. We
+were only matching 3-letter words, or chunks of words of 4 letters or
+less. We'd like to be able to match words or, more generally, strings
+of any length, without writing out tedious alternatives like
+C<\w\w\w\w|\w\w\w|\w\w|\w>.
+
+This is exactly the problem the I<quantifier> metacharacters C<?>,
+C<*>, C<+>, and C<{}> were created for. They allow us to delimit the
+number of repeats for a portion of a regexp we consider to be a
+match. Quantifiers are put immediately after the character, character
+class, or grouping that we want to specify. They have the following
+meanings:
+
+=over 4
+
+=item *
+
+C<a?> means: match 'a' 1 or 0 times
+
+=item *
+
+C<a*> means: match 'a' 0 or more times, i.e., any number of times
+
+=item *
+
+C<a+> means: match 'a' 1 or more times, i.e., at least once
+
+=item *
+
+C<a{n,m}> means: match at least C<n> times, but not more than C<m>
+times.
+
+=item *
+
+C<a{n,}> means: match at least C<n> or more times
+
+=item *
+
+C<a{n}> means: match exactly C<n> times
+
+=back
+
+Here are some examples:
+
+ /[a-z]+\s+\d*/; # match a lowercase word, at least one space, and
+ # any number of digits
+ /(\w+)\s+\1/; # match doubled words of arbitrary length
+ /y(es)?/i; # matches 'y', 'Y', or a case-insensitive 'yes'
+ $year =~ /\d{2,4}/; # make sure year is at least 2 but not more
+ # than 4 digits
+ $year =~ /\d{4}|\d{2}/; # better match; throw out 3 digit dates
+ $year =~ /\d{2}(\d{2})?/; # same thing written differently. However,
+ # this produces $1 and the other does not.
+
+ % simple_grep '^(\w+)\1$' /usr/dict/words # isn't this easier?
+ beriberi
+ booboo
+ coco
+ mama
+ murmur
+ papa
+
+For all of these quantifiers, Perl will try to match as much of the
+string as possible, while still allowing the regexp to succeed. Thus
+with C</a?.../>, Perl will first try to match the regexp with the C<a>
+present; if that fails, Perl will try to match the regexp without the
+C<a> present. For the quantifier C<*>, we get the following:
+
+ $x = "the cat in the hat";
+ $x =~ /^(.*)(cat)(.*)$/; # matches,
+ # $1 = 'the '
+ # $2 = 'cat'
+ # $3 = ' in the hat'
+
+Which is what we might expect, the match finds the only C<cat> in the
+string and locks onto it. Consider, however, this regexp:
+
+ $x =~ /^(.*)(at)(.*)$/; # matches,
+ # $1 = 'the cat in the h'
+ # $2 = 'at'
+ # $3 = '' (0 characters match)
+
+One might initially guess that Perl would find the C<at> in C<cat> and
+stop there, but that wouldn't give the longest possible string to the
+first quantifier C<.*>. Instead, the first quantifier C<.*> grabs as
+much of the string as possible while still having the regexp match. In
+this example, that means having the C<at> sequence with the final C<at>
+in the string. The other important principle illustrated here is that
+when there are two or more elements in a regexp, the I<leftmost>
+quantifier, if there is one, gets to grab as much the string as
+possible, leaving the rest of the regexp to fight over scraps. Thus in
+our example, the first quantifier C<.*> grabs most of the string, while
+the second quantifier C<.*> gets the empty string. Quantifiers that
+grab as much of the string as possible are called I<maximal match> or
+I<greedy> quantifiers.
+
+When a regexp can match a string in several different ways, we can use
+the principles above to predict which way the regexp will match:
+
+=over 4
+
+=item *
+
+Principle 0: Taken as a whole, any regexp will be matched at the
+earliest possible position in the string.
+
+=item *
+
+Principle 1: In an alternation C<a|b|c...>, the leftmost alternative
+that allows a match for the whole regexp will be the one used.
+
+=item *
+
+Principle 2: The maximal matching quantifiers C<?>, C<*>, C<+> and
+C<{n,m}> will in general match as much of the string as possible while
+still allowing the whole regexp to match.
+
+=item *
+
+Principle 3: If there are two or more elements in a regexp, the
+leftmost greedy quantifier, if any, will match as much of the string
+as possible while still allowing the whole regexp to match. The next
+leftmost greedy quantifier, if any, will try to match as much of the
+string remaining available to it as possible, while still allowing the
+whole regexp to match. And so on, until all the regexp elements are
+satisfied.
+
+=back
+
+As we have seen above, Principle 0 overrides the others. The regexp
+will be matched as early as possible, with the other principles
+determining how the regexp matches at that earliest character
+position.
+
+Here is an example of these principles in action:
+
+ $x = "The programming republic of Perl";
+ $x =~ /^(.+)(e|r)(.*)$/; # matches,
+ # $1 = 'The programming republic of Pe'
+ # $2 = 'r'
+ # $3 = 'l'
+
+This regexp matches at the earliest string position, C<'T'>. One
+might think that C<e>, being leftmost in the alternation, would be
+matched, but C<r> produces the longest string in the first quantifier.
+
+ $x =~ /(m{1,2})(.*)$/; # matches,
+ # $1 = 'mm'
+ # $2 = 'ing republic of Perl'
+
+Here, The earliest possible match is at the first C<'m'> in
+C<programming>. C<m{1,2}> is the first quantifier, so it gets to match
+a maximal C<mm>.
+
+ $x =~ /.*(m{1,2})(.*)$/; # matches,
+ # $1 = 'm'
+ # $2 = 'ing republic of Perl'
+
+Here, the regexp matches at the start of the string. The first
+quantifier C<.*> grabs as much as possible, leaving just a single
+C<'m'> for the second quantifier C<m{1,2}>.
+
+ $x =~ /(.?)(m{1,2})(.*)$/; # matches,
+ # $1 = 'a'
+ # $2 = 'mm'
+ # $3 = 'ing republic of Perl'
+
+Here, C<.?> eats its maximal one character at the earliest possible
+position in the string, C<'a'> in C<programming>, leaving C<m{1,2}>
+the opportunity to match both C<m>'s. Finally,
+
+ "aXXXb" =~ /(X*)/; # matches with $1 = ''
+
+because it can match zero copies of C<'X'> at the beginning of the
+string. If you definitely want to match at least one C<'X'>, use
+C<X+>, not C<X*>.
+
+Sometimes greed is not good. At times, we would like quantifiers to
+match a I<minimal> piece of string, rather than a maximal piece. For
+this purpose, Larry Wall created the I<minimal match> or
+I<non-greedy> quantifiers C<??>, C<*?>, C<+?>, and C<{}?>. These are
+the usual quantifiers with a C<?> appended to them. They have the
+following meanings:
+
+=over 4
+
+=item *
+
+C<a??> means: match 'a' 0 or 1 times. Try 0 first, then 1.
+
+=item *
+
+C<a*?> means: match 'a' 0 or more times, i.e., any number of times,
+but as few times as possible
+
+=item *
+
+C<a+?> means: match 'a' 1 or more times, i.e., at least once, but
+as few times as possible
+
+=item *
+
+C<a{n,m}?> means: match at least C<n> times, not more than C<m>
+times, as few times as possible
+
+=item *
+
+C<a{n,}?> means: match at least C<n> times, but as few times as
+possible
+
+=item *
+
+C<a{n}?> means: match exactly C<n> times. Because we match exactly
+C<n> times, C<a{n}?> is equivalent to C<a{n}> and is just there for
+notational consistency.
+
+=back
+
+Let's look at the example above, but with minimal quantifiers:
+
+ $x = "The programming republic of Perl";
+ $x =~ /^(.+?)(e|r)(.*)$/; # matches,
+ # $1 = 'Th'
+ # $2 = 'e'
+ # $3 = ' programming republic of Perl'
+
+The minimal string that will allow both the start of the string C<^>
+and the alternation to match is C<Th>, with the alternation C<e|r>
+matching C<e>. The second quantifier C<.*> is free to gobble up the
+rest of the string.
+
+ $x =~ /(m{1,2}?)(.*?)$/; # matches,
+ # $1 = 'm'
+ # $2 = 'ming republic of Perl'
+
+The first string position that this regexp can match is at the first
+C<'m'> in C<programming>. At this position, the minimal C<m{1,2}?>
+matches just one C<'m'>. Although the second quantifier C<.*?> would
+prefer to match no characters, it is constrained by the end-of-string
+anchor C<$> to match the rest of the string.
+
+ $x =~ /(.*?)(m{1,2}?)(.*)$/; # matches,
+ # $1 = 'The progra'
+ # $2 = 'm'
+ # $3 = 'ming republic of Perl'
+
+In this regexp, you might expect the first minimal quantifier C<.*?>
+to match the empty string, because it is not constrained by a C<^>
+anchor to match the beginning of the word. Principle 0 applies here,
+however. Because it is possible for the whole regexp to match at the
+start of the string, it I<will> match at the start of the string. Thus
+the first quantifier has to match everything up to the first C<m>. The
+second minimal quantifier matches just one C<m> and the third
+quantifier matches the rest of the string.
+
+ $x =~ /(.??)(m{1,2})(.*)$/; # matches,
+ # $1 = 'a'
+ # $2 = 'mm'
+ # $3 = 'ing republic of Perl'
+
+Just as in the previous regexp, the first quantifier C<.??> can match
+earliest at position C<'a'>, so it does. The second quantifier is
+greedy, so it matches C<mm>, and the third matches the rest of the
+string.
+
+We can modify principle 3 above to take into account non-greedy
+quantifiers:
+
+=over 4
+
+=item *
+
+Principle 3: If there are two or more elements in a regexp, the
+leftmost greedy (non-greedy) quantifier, if any, will match as much
+(little) of the string as possible while still allowing the whole
+regexp to match. The next leftmost greedy (non-greedy) quantifier, if
+any, will try to match as much (little) of the string remaining
+available to it as possible, while still allowing the whole regexp to
+match. And so on, until all the regexp elements are satisfied.
+
+=back
+
+Just like alternation, quantifiers are also susceptible to
+backtracking. Here is a step-by-step analysis of the example
+
+ $x = "the cat in the hat";
+ $x =~ /^(.*)(at)(.*)$/; # matches,
+ # $1 = 'the cat in the h'
+ # $2 = 'at'
+ # $3 = '' (0 matches)
+
+=over 4
+
+=item 0
+
+Start with the first letter in the string 't'.
+
+=item 1
+
+The first quantifier '.*' starts out by matching the whole
+string 'the cat in the hat'.
+
+=item 2
+
+'a' in the regexp element 'at' doesn't match the end of the
+string. Backtrack one character.
+
+=item 3
+
+'a' in the regexp element 'at' still doesn't match the last
+letter of the string 't', so backtrack one more character.
+
+=item 4
+
+Now we can match the 'a' and the 't'.
+
+=item 5
+
+Move on to the third element '.*'. Since we are at the end of
+the string and '.*' can match 0 times, assign it the empty string.
+
+=item 6
+
+We are done!
+
+=back
+
+Most of the time, all this moving forward and backtracking happens
+quickly and searching is fast. There are some pathological regexps,
+however, whose execution time exponentially grows with the size of the
+string. A typical structure that blows up in your face is of the form
+
+ /(a|b+)*/;
+
+The problem is the nested indeterminate quantifiers. There are many
+different ways of partitioning a string of length n between the C<+>
+and C<*>: one repetition with C<b+> of length n, two repetitions with
+the first C<b+> length k and the second with length n-k, m repetitions
+whose bits add up to length n, etc. In fact there are an exponential
+number of ways to partition a string as a function of its length. A
+regexp may get lucky and match early in the process, but if there is
+no match, Perl will try I<every> possibility before giving up. So be
+careful with nested C<*>'s, C<{n,m}>'s, and C<+>'s. The book
+I<Mastering Regular Expressions> by Jeffrey Friedl gives a wonderful
+discussion of this and other efficiency issues.
+
+
+=head2 Possessive quantifiers
+
+Backtracking during the relentless search for a match may be a waste
+of time, particularly when the match is bound to fail. Consider
+the simple pattern
+
+ /^\w+\s+\w+$/; # a word, spaces, a word
+
+Whenever this is applied to a string which doesn't quite meet the
+pattern's expectations such as S<C<"abc ">> or S<C<"abc def ">>,
+the regex engine will backtrack, approximately once for each character
+in the string. But we know that there is no way around taking I<all>
+of the initial word characters to match the first repetition, that I<all>
+spaces must be eaten by the middle part, and the same goes for the second
+word.
+
+With the introduction of the I<possessive quantifiers> in Perl 5.10, we
+have a way of instructing the regex engine not to backtrack, with the
+usual quantifiers with a C<+> appended to them. This makes them greedy as
+well as stingy; once they succeed they won't give anything back to permit
+another solution. They have the following meanings:
+
+=over 4
+
+=item *
+
+C<a{n,m}+> means: match at least C<n> times, not more than C<m> times,
+as many times as possible, and don't give anything up. C<a?+> is short
+for C<a{0,1}+>
+
+=item *
+
+C<a{n,}+> means: match at least C<n> times, but as many times as possible,
+and don't give anything up. C<a*+> is short for C<a{0,}+> and C<a++> is
+short for C<a{1,}+>.
+
+=item *
+
+C<a{n}+> means: match exactly C<n> times. It is just there for
+notational consistency.
+
+=back
+
+These possessive quantifiers represent a special case of a more general
+concept, the I<independent subexpression>, see below.
+
+As an example where a possessive quantifier is suitable we consider
+matching a quoted string, as it appears in several programming languages.
+The backslash is used as an escape character that indicates that the
+next character is to be taken literally, as another character for the
+string. Therefore, after the opening quote, we expect a (possibly
+empty) sequence of alternatives: either some character except an
+unescaped quote or backslash or an escaped character.
+
+ /"(?:[^"\\]++|\\.)*+"/;
+
+
+=head2 Building a regexp
+
+At this point, we have all the basic regexp concepts covered, so let's
+give a more involved example of a regular expression. We will build a
+regexp that matches numbers.
+
+The first task in building a regexp is to decide what we want to match
+and what we want to exclude. In our case, we want to match both
+integers and floating point numbers and we want to reject any string
+that isn't a number.
+
+The next task is to break the problem down into smaller problems that
+are easily converted into a regexp.
+
+The simplest case is integers. These consist of a sequence of digits,
+with an optional sign in front. The digits we can represent with
+C<\d+> and the sign can be matched with C<[+-]>. Thus the integer
+regexp is
+
+ /[+-]?\d+/; # matches integers
+
+A floating point number potentially has a sign, an integral part, a
+decimal point, a fractional part, and an exponent. One or more of these
+parts is optional, so we need to check out the different
+possibilities. Floating point numbers which are in proper form include
+123., 0.345, .34, -1e6, and 25.4E-72. As with integers, the sign out
+front is completely optional and can be matched by C<[+-]?>. We can
+see that if there is no exponent, floating point numbers must have a
+decimal point, otherwise they are integers. We might be tempted to
+model these with C<\d*\.\d*>, but this would also match just a single
+decimal point, which is not a number. So the three cases of floating
+point number without exponent are
+
+ /[+-]?\d+\./; # 1., 321., etc.
+ /[+-]?\.\d+/; # .1, .234, etc.
+ /[+-]?\d+\.\d+/; # 1.0, 30.56, etc.
+
+These can be combined into a single regexp with a three-way alternation:
+
+ /[+-]?(\d+\.\d+|\d+\.|\.\d+)/; # floating point, no exponent
+
+In this alternation, it is important to put C<'\d+\.\d+'> before
+C<'\d+\.'>. If C<'\d+\.'> were first, the regexp would happily match that
+and ignore the fractional part of the number.
+
+Now consider floating point numbers with exponents. The key
+observation here is that I<both> integers and numbers with decimal
+points are allowed in front of an exponent. Then exponents, like the
+overall sign, are independent of whether we are matching numbers with
+or without decimal points, and can be 'decoupled' from the
+mantissa. The overall form of the regexp now becomes clear:
+
+ /^(optional sign)(integer | f.p. mantissa)(optional exponent)$/;
+
+The exponent is an C<e> or C<E>, followed by an integer. So the
+exponent regexp is
+
+ /[eE][+-]?\d+/; # exponent
+
+Putting all the parts together, we get a regexp that matches numbers:
+
+ /^[+-]?(\d+\.\d+|\d+\.|\.\d+|\d+)([eE][+-]?\d+)?$/; # Ta da!
+
+Long regexps like this may impress your friends, but can be hard to
+decipher. In complex situations like this, the C<//x> modifier for a
+match is invaluable. It allows one to put nearly arbitrary whitespace
+and comments into a regexp without affecting their meaning. Using it,
+we can rewrite our 'extended' regexp in the more pleasing form
+
+ /^
+ [+-]? # first, match an optional sign
+ ( # then match integers or f.p. mantissas:
+ \d+\.\d+ # mantissa of the form a.b
+ |\d+\. # mantissa of the form a.
+ |\.\d+ # mantissa of the form .b
+ |\d+ # integer of the form a
+ )
+ ([eE][+-]?\d+)? # finally, optionally match an exponent
+ $/x;
+
+If whitespace is mostly irrelevant, how does one include space
+characters in an extended regexp? The answer is to backslash it
+S<C<'\ '>> or put it in a character class S<C<[ ]>>. The same thing
+goes for pound signs, use C<\#> or C<[#]>. For instance, Perl allows
+a space between the sign and the mantissa or integer, and we could add
+this to our regexp as follows:
+
+ /^
+ [+-]?\ * # first, match an optional sign *and space*
+ ( # then match integers or f.p. mantissas:
+ \d+\.\d+ # mantissa of the form a.b
+ |\d+\. # mantissa of the form a.
+ |\.\d+ # mantissa of the form .b
+ |\d+ # integer of the form a
+ )
+ ([eE][+-]?\d+)? # finally, optionally match an exponent
+ $/x;
+
+In this form, it is easier to see a way to simplify the
+alternation. Alternatives 1, 2, and 4 all start with C<\d+>, so it
+could be factored out:
+
+ /^
+ [+-]?\ * # first, match an optional sign
+ ( # then match integers or f.p. mantissas:
+ \d+ # start out with a ...
+ (
+ \.\d* # mantissa of the form a.b or a.
+ )? # ? takes care of integers of the form a
+ |\.\d+ # mantissa of the form .b
+ )
+ ([eE][+-]?\d+)? # finally, optionally match an exponent
+ $/x;
+
+or written in the compact form,
+
+ /^[+-]?\ *(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?$/;
+
+This is our final regexp. To recap, we built a regexp by
+
+=over 4
+
+=item *
+
+specifying the task in detail,
+
+=item *
+
+breaking down the problem into smaller parts,
+
+=item *
+
+translating the small parts into regexps,
+
+=item *
+
+combining the regexps,
+
+=item *
+
+and optimizing the final combined regexp.
+
+=back
+
+These are also the typical steps involved in writing a computer
+program. This makes perfect sense, because regular expressions are
+essentially programs written in a little computer language that specifies
+patterns.
+
+=head2 Using regular expressions in Perl
+
+The last topic of Part 1 briefly covers how regexps are used in Perl
+programs. Where do they fit into Perl syntax?
+
+We have already introduced the matching operator in its default
+C</regexp/> and arbitrary delimiter C<m!regexp!> forms. We have used
+the binding operator C<=~> and its negation C<!~> to test for string
+matches. Associated with the matching operator, we have discussed the
+single line C<//s>, multi-line C<//m>, case-insensitive C<//i> and
+extended C<//x> modifiers. There are a few more things you might
+want to know about matching operators.
+
+=head3 Optimizing pattern evaluation
+
+We pointed out earlier that variables in regexps are substituted
+before the regexp is evaluated:
+
+ $pattern = 'Seuss';
+ while (<>) {
+ print if /$pattern/;
+ }
+
+This will print any lines containing the word C<Seuss>. It is not as
+efficient as it could be, however, because Perl has to re-evaluate
+(or compile) C<$pattern> each time through the loop. If C<$pattern> won't be
+changing over the lifetime of the script, we can add the C<//o>
+modifier, which directs Perl to only perform variable substitutions
+once:
+
+ #!/usr/bin/perl
+ # Improved simple_grep
+ $regexp = shift;
+ while (<>) {
+ print if /$regexp/o; # a good deal faster
+ }
+
+
+=head3 Prohibiting substitution
+
+If you change C<$pattern> after the first substitution happens, Perl
+will ignore it. If you don't want any substitutions at all, use the
+special delimiter C<m''>:
+
+ @pattern = ('Seuss');
+ while (<>) {
+ print if m'@pattern'; # matches literal '@pattern', not 'Seuss'
+ }
+
+Similar to strings, C<m''> acts like apostrophes on a regexp; all other
+C<m> delimiters act like quotes. If the regexp evaluates to the empty string,
+the regexp in the I<last successful match> is used instead. So we have
+
+ "dog" =~ /d/; # 'd' matches
+ "dogbert =~ //; # this matches the 'd' regexp used before
+
+
+=head3 Global matching
+
+The final two modifiers C<//g> and C<//c> concern multiple matches.
+The modifier C<//g> stands for global matching and allows the
+matching operator to match within a string as many times as possible.
+In scalar context, successive invocations against a string will have
+`C<//g> jump from match to match, keeping track of position in the
+string as it goes along. You can get or set the position with the
+C<pos()> function.
+
+The use of C<//g> is shown in the following example. Suppose we have
+a string that consists of words separated by spaces. If we know how
+many words there are in advance, we could extract the words using
+groupings:
+
+ $x = "cat dog house"; # 3 words
+ $x =~ /^\s*(\w+)\s+(\w+)\s+(\w+)\s*$/; # matches,
+ # $1 = 'cat'
+ # $2 = 'dog'
+ # $3 = 'house'
+
+But what if we had an indeterminate number of words? This is the sort
+of task C<//g> was made for. To extract all words, form the simple
+regexp C<(\w+)> and loop over all matches with C</(\w+)/g>:
+
+ while ($x =~ /(\w+)/g) {
+ print "Word is $1, ends at position ", pos $x, "\n";
+ }
+
+prints
+
+ Word is cat, ends at position 3
+ Word is dog, ends at position 7
+ Word is house, ends at position 13
+
+A failed match or changing the target string resets the position. If
+you don't want the position reset after failure to match, add the
+C<//c>, as in C</regexp/gc>. The current position in the string is
+associated with the string, not the regexp. This means that different
+strings have different positions and their respective positions can be
+set or read independently.
+
+In list context, C<//g> returns a list of matched groupings, or if
+there are no groupings, a list of matches to the whole regexp. So if
+we wanted just the words, we could use
+
+ @words = ($x =~ /(\w+)/g); # matches,
+ # $word[0] = 'cat'
+ # $word[1] = 'dog'
+ # $word[2] = 'house'
+
+Closely associated with the C<//g> modifier is the C<\G> anchor. The
+C<\G> anchor matches at the point where the previous C<//g> match left
+off. C<\G> allows us to easily do context-sensitive matching:
+
+ $metric = 1; # use metric units
+ ...
+ $x = <FILE>; # read in measurement
+ $x =~ /^([+-]?\d+)\s*/g; # get magnitude
+ $weight = $1;
+ if ($metric) { # error checking
+ print "Units error!" unless $x =~ /\Gkg\./g;
+ }
+ else {
+ print "Units error!" unless $x =~ /\Glbs\./g;
+ }
+ $x =~ /\G\s+(widget|sprocket)/g; # continue processing
+
+The combination of C<//g> and C<\G> allows us to process the string a
+bit at a time and use arbitrary Perl logic to decide what to do next.
+Currently, the C<\G> anchor is only fully supported when used to anchor
+to the start of the pattern.
+
+C<\G> is also invaluable in processing fixed length records with
+regexps. Suppose we have a snippet of coding region DNA, encoded as
+base pair letters C<ATCGTTGAAT...> and we want to find all the stop
+codons C<TGA>. In a coding region, codons are 3-letter sequences, so
+we can think of the DNA snippet as a sequence of 3-letter records. The
+naive regexp
+
+ # expanded, this is "ATC GTT GAA TGC AAA TGA CAT GAC"
+ $dna = "ATCGTTGAATGCAAATGACATGAC";
+ $dna =~ /TGA/;
+
+doesn't work; it may match a C<TGA>, but there is no guarantee that
+the match is aligned with codon boundaries, e.g., the substring
+S<C<GTT GAA>> gives a match. A better solution is
+
+ while ($dna =~ /(\w\w\w)*?TGA/g) { # note the minimal *?
+ print "Got a TGA stop codon at position ", pos $dna, "\n";
+ }
+
+which prints
+
+ Got a TGA stop codon at position 18
+ Got a TGA stop codon at position 23
+
+Position 18 is good, but position 23 is bogus. What happened?
+
+The answer is that our regexp works well until we get past the last
+real match. Then the regexp will fail to match a synchronized C<TGA>
+and start stepping ahead one character position at a time, not what we
+want. The solution is to use C<\G> to anchor the match to the codon
+alignment:
+
+ while ($dna =~ /\G(\w\w\w)*?TGA/g) {
+ print "Got a TGA stop codon at position ", pos $dna, "\n";
+ }
+
+This prints
+
+ Got a TGA stop codon at position 18
+
+which is the correct answer. This example illustrates that it is
+important not only to match what is desired, but to reject what is not
+desired.
+
+=head3 Search and replace
+
+Regular expressions also play a big role in I<search and replace>
+operations in Perl. Search and replace is accomplished with the
+C<s///> operator. The general form is
+C<s/regexp/replacement/modifiers>, with everything we know about
+regexps and modifiers applying in this case as well. The
+C<replacement> is a Perl double quoted string that replaces in the
+string whatever is matched with the C<regexp>. The operator C<=~> is
+also used here to associate a string with C<s///>. If matching
+against C<$_>, the S<C<$_ =~>> can be dropped. If there is a match,
+C<s///> returns the number of substitutions made, otherwise it returns
+false. Here are a few examples:
+
+ $x = "Time to feed the cat!";
+ $x =~ s/cat/hacker/; # $x contains "Time to feed the hacker!"
+ if ($x =~ s/^(Time.*hacker)!$/$1 now!/) {
+ $more_insistent = 1;
+ }
+ $y = "'quoted words'";
+ $y =~ s/^'(.*)'$/$1/; # strip single quotes,
+ # $y contains "quoted words"
+
+In the last example, the whole string was matched, but only the part
+inside the single quotes was grouped. With the C<s///> operator, the
+matched variables C<$1>, C<$2>, etc. are immediately available for use
+in the replacement expression, so we use C<$1> to replace the quoted
+string with just what was quoted. With the global modifier, C<s///g>
+will search and replace all occurrences of the regexp in the string:
+
+ $x = "I batted 4 for 4";
+ $x =~ s/4/four/; # doesn't do it all:
+ # $x contains "I batted four for 4"
+ $x = "I batted 4 for 4";
+ $x =~ s/4/four/g; # does it all:
+ # $x contains "I batted four for four"
+
+If you prefer 'regex' over 'regexp' in this tutorial, you could use
+the following program to replace it:
+
+ % cat > simple_replace
+ #!/usr/bin/perl
+ $regexp = shift;
+ $replacement = shift;
+ while (<>) {
+ s/$regexp/$replacement/go;
+ print;
+ }
+ ^D
+
+ % simple_replace regexp regex perlretut.pod
+
+In C<simple_replace> we used the C<s///g> modifier to replace all
+occurrences of the regexp on each line and the C<s///o> modifier to
+compile the regexp only once. As with C<simple_grep>, both the
+C<print> and the C<s/$regexp/$replacement/go> use C<$_> implicitly.
+
+A modifier available specifically to search and replace is the
+C<s///e> evaluation modifier. C<s///e> wraps an C<eval{...}> around
+the replacement string and the evaluated result is substituted for the
+matched substring. C<s///e> is useful if you need to do a bit of
+computation in the process of replacing text. This example counts
+character frequencies in a line:
+
+ $x = "Bill the cat";
+ $x =~ s/(.)/$chars{$1}++;$1/eg; # final $1 replaces char with itself
+ print "frequency of '$_' is $chars{$_}\n"
+ foreach (sort {$chars{$b} <=> $chars{$a}} keys %chars);
+
+This prints
+
+ frequency of ' ' is 2
+ frequency of 't' is 2
+ frequency of 'l' is 2
+ frequency of 'B' is 1
+ frequency of 'c' is 1
+ frequency of 'e' is 1
+ frequency of 'h' is 1
+ frequency of 'i' is 1
+ frequency of 'a' is 1
+
+As with the match C<m//> operator, C<s///> can use other delimiters,
+such as C<s!!!> and C<s{}{}>, and even C<s{}//>. If single quotes are
+used C<s'''>, then the regexp and replacement are treated as single
+quoted strings and there are no substitutions. C<s///> in list context
+returns the same thing as in scalar context, i.e., the number of
+matches.
+
+=head3 The split function
+
+The C<split()> function is another place where a regexp is used.
+C<split /regexp/, string, limit> separates the C<string> operand into
+a list of substrings and returns that list. The regexp must be designed
+to match whatever constitutes the separators for the desired substrings.
+The C<limit>, if present, constrains splitting into no more than C<limit>
+number of strings. For example, to split a string into words, use
+
+ $x = "Calvin and Hobbes";
+ @words = split /\s+/, $x; # $word[0] = 'Calvin'
+ # $word[1] = 'and'
+ # $word[2] = 'Hobbes'
+
+If the empty regexp C<//> is used, the regexp always matches and
+the string is split into individual characters. If the regexp has
+groupings, then the resulting list contains the matched substrings from the
+groupings as well. For instance,
+
+ $x = "/usr/bin/perl";
+ @dirs = split m!/!, $x; # $dirs[0] = ''
+ # $dirs[1] = 'usr'
+ # $dirs[2] = 'bin'
+ # $dirs[3] = 'perl'
+ @parts = split m!(/)!, $x; # $parts[0] = ''
+ # $parts[1] = '/'
+ # $parts[2] = 'usr'
+ # $parts[3] = '/'
+ # $parts[4] = 'bin'
+ # $parts[5] = '/'
+ # $parts[6] = 'perl'
+
+Since the first character of $x matched the regexp, C<split> prepended
+an empty initial element to the list.
+
+If you have read this far, congratulations! You now have all the basic
+tools needed to use regular expressions to solve a wide range of text
+processing problems. If this is your first time through the tutorial,
+why not stop here and play around with regexps a while... S<Part 2>
+concerns the more esoteric aspects of regular expressions and those
+concepts certainly aren't needed right at the start.
+
+=head1 Part 2: Power tools
+
+OK, you know the basics of regexps and you want to know more. If
+matching regular expressions is analogous to a walk in the woods, then
+the tools discussed in Part 1 are analogous to topo maps and a
+compass, basic tools we use all the time. Most of the tools in part 2
+are analogous to flare guns and satellite phones. They aren't used
+too often on a hike, but when we are stuck, they can be invaluable.
+
+What follows are the more advanced, less used, or sometimes esoteric
+capabilities of Perl regexps. In Part 2, we will assume you are
+comfortable with the basics and concentrate on the new features.
+
+=head2 More on characters, strings, and character classes
+
+There are a number of escape sequences and character classes that we
+haven't covered yet.
+
+There are several escape sequences that convert characters or strings
+between upper and lower case, and they are also available within
+patterns. C<\l> and C<\u> convert the next character to lower or
+upper case, respectively:
+
+ $x = "perl";
+ $string =~ /\u$x/; # matches 'Perl' in $string
+ $x = "M(rs?|s)\\."; # note the double backslash
+ $string =~ /\l$x/; # matches 'mr.', 'mrs.', and 'ms.',
+
+A C<\L> or C<\U> indicates a lasting conversion of case, until
+terminated by C<\E> or thrown over by another C<\U> or C<\L>:
+
+ $x = "This word is in lower case:\L SHOUT\E";
+ $x =~ /shout/; # matches
+ $x = "I STILL KEYPUNCH CARDS FOR MY 360"
+ $x =~ /\Ukeypunch/; # matches punch card string
+
+If there is no C<\E>, case is converted until the end of the
+string. The regexps C<\L\u$word> or C<\u\L$word> convert the first
+character of C<$word> to uppercase and the rest of the characters to
+lowercase.
+
+Control characters can be escaped with C<\c>, so that a control-Z
+character would be matched with C<\cZ>. The escape sequence
+C<\Q>...C<\E> quotes, or protects most non-alphabetic characters. For
+instance,
+
+ $x = "\QThat !^*&%~& cat!";
+ $x =~ /\Q!^*&%~&\E/; # check for rough language
+
+It does not protect C<$> or C<@>, so that variables can still be
+substituted.
+
+With the advent of 5.6.0, Perl regexps can handle more than just the
+standard ASCII character set. Perl now supports I<Unicode>, a standard
+for representing the alphabets from virtually all of the world's written
+languages, and a host of symbols. Perl's text strings are Unicode strings, so
+they can contain characters with a value (codepoint or character number) higher
+than 255
+
+What does this mean for regexps? Well, regexp users don't need to know
+much about Perl's internal representation of strings. But they do need
+to know 1) how to represent Unicode characters in a regexp and 2) that
+a matching operation will treat the string to be searched as a sequence
+of characters, not bytes. The answer to 1) is that Unicode characters
+greater than C<chr(255)> are represented using the C<\x{hex}> notation,
+because the \0 octal and \x hex (without curly braces) don't go further
+than 255.
+
+ /\x{263a}/; # match a Unicode smiley face :)
+
+B<NOTE>: In Perl 5.6.0 it used to be that one needed to say C<use
+utf8> to use any Unicode features. This is no more the case: for
+almost all Unicode processing, the explicit C<utf8> pragma is not
+needed. (The only case where it matters is if your Perl script is in
+Unicode and encoded in UTF-8, then an explicit C<use utf8> is needed.)
+
+Figuring out the hexadecimal sequence of a Unicode character you want
+or deciphering someone else's hexadecimal Unicode regexp is about as
+much fun as programming in machine code. So another way to specify
+Unicode characters is to use the I<named character> escape
+sequence C<\N{I<name>}>. I<name> is a name for the Unicode character, as
+specified in the Unicode standard. For instance, if we wanted to
+represent or match the astrological sign for the planet Mercury, we
+could use
+
+ use charnames ":full"; # use named chars with Unicode full names
+ $x = "abc\N{MERCURY}def";
+ $x =~ /\N{MERCURY}/; # matches
+
+One can also use short names or restrict names to a certain alphabet:
+
+ use charnames ':full';
+ print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";
+
+ use charnames ":short";
+ print "\N{greek:Sigma} is an upper-case sigma.\n";
+
+ use charnames qw(greek);
+ print "\N{sigma} is Greek sigma\n";
+
+A list of full names is found in the file NamesList.txt in the
+lib/perl5/X.X.X/unicore directory (where X.X.X is the perl
+version number as it is installed on your system).
+
+The answer to requirement 2), as of 5.6.0, is that a regexp uses Unicode
+characters. Internally, this is encoded to bytes using either UTF-8 or a
+native 8 bit encoding, depending on the history of the string, but
+conceptually it is a sequence of characters, not bytes. See
+L<perlunitut> for a tutorial about that.
+
+Let us now discuss Unicode character classes. Just as with Unicode
+characters, there are named Unicode character classes represented by the
+C<\p{name}> escape sequence. Closely associated is the C<\P{name}>
+character class, which is the negation of the C<\p{name}> class. For
+example, to match lower and uppercase characters,
+
+ use charnames ":full"; # use named chars with Unicode full names
+ $x = "BOB";
+ $x =~ /^\p{IsUpper}/; # matches, uppercase char class
+ $x =~ /^\P{IsUpper}/; # doesn't match, char class sans uppercase
+ $x =~ /^\p{IsLower}/; # doesn't match, lowercase char class
+ $x =~ /^\P{IsLower}/; # matches, char class sans lowercase
+
+Here is the association between some Perl named classes and the
+traditional Unicode classes:
+
+ Perl class name Unicode class name or regular expression
+
+ IsAlpha /^[LM]/
+ IsAlnum /^[LMN]/
+ IsASCII $code <= 127
+ IsCntrl /^C/
+ IsBlank $code =~ /^(0020|0009)$/ || /^Z[^lp]/
+ IsDigit Nd
+ IsGraph /^([LMNPS]|Co)/
+ IsLower Ll
+ IsPrint /^([LMNPS]|Co|Zs)/
+ IsPunct /^P/
+ IsSpace /^Z/ || ($code =~ /^(0009|000A|000B|000C|000D)$/
+ IsSpacePerl /^Z/ || ($code =~ /^(0009|000A|000C|000D|0085|2028|2029)$/
+ IsUpper /^L[ut]/
+ IsWord /^[LMN]/ || $code eq "005F"
+ IsXDigit $code =~ /^00(3[0-9]|[46][1-6])$/
+
+You can also use the official Unicode class names with the C<\p> and
+C<\P>, like C<\p{L}> for Unicode 'letters', or C<\p{Lu}> for uppercase
+letters, or C<\P{Nd}> for non-digits. If a C<name> is just one
+letter, the braces can be dropped. For instance, C<\pM> is the
+character class of Unicode 'marks', for example accent marks.
+For the full list see L<perlunicode>.
+
+The Unicode has also been separated into various sets of characters
+which you can test with C<\p{...}> (in) and C<\P{...}> (not in).
+To test whether a character is (or is not) an element of a script
+you would use the script name, for example C<\p{Latin}>, C<\p{Greek}>,
+or C<\P{Katakana}>. Other sets are the Unicode blocks, the names
+of which begin with "In". One such block is dedicated to mathematical
+operators, and its pattern formula is <C\p{InMathematicalOperators>}>.
+For the full list see L<perluniprops>.
+
+What we have described so far is the single form of the C<\p{...}> character
+classes. There is also a compound form which you may run into. These
+look like C<\p{name=value}> or C<\p{name:value}> (the equals sign and colon
+can be used interchangeably). These are more general than the single form,
+and in fact most of the single forms are just Perl-defined shortcuts for common
+compound forms. For example, the script examples in the previous paragraph
+could be written equivalently as C<\p{Script=Latin}>, C<\p{Script:Greek}>, and
+C<\P{script=katakana}> (case is irrelevant between the C<{}> braces). You may
+never have to use the compound forms, but sometimes it is necessary, and their
+use can make your code easier to understand.
+
+C<\X> is an abbreviation for a character class that comprises
+a Unicode I<extended grapheme cluster>. This represents a "logical character",
+what appears to be a single character, but may be represented internally by more
+than one. As an example, using the Unicode full names, e.g., S<C<A + COMBINING
+RING>> is a grapheme cluster with base character C<A> and combining character
+S<C<COMBINING RING>>, which translates in Danish to A with the circle atop it,
+as in the word Angstrom.
+
+For the full and latest information about Unicode see the latest
+Unicode standard, or the Unicode Consortium's website L<http://www.unicode.org>
+
+As if all those classes weren't enough, Perl also defines POSIX style
+character classes. These have the form C<[:name:]>, with C<name> the
+name of the POSIX class. The POSIX classes are C<alpha>, C<alnum>,
+C<ascii>, C<cntrl>, C<digit>, C<graph>, C<lower>, C<print>, C<punct>,
+C<space>, C<upper>, and C<xdigit>, and two extensions, C<word> (a Perl
+extension to match C<\w>), and C<blank> (a GNU extension). If C<utf8>
+is being used, then these classes are defined the same as their
+corresponding Perl Unicode classes: C<[:upper:]> is the same as
+C<\p{IsUpper}>, etc. The POSIX character classes, however, don't
+require using C<utf8>. The C<[:digit:]>, C<[:word:]>, and
+C<[:space:]> correspond to the familiar C<\d>, C<\w>, and C<\s>
+character classes. To negate a POSIX class, put a C<^> in front of
+the name, so that, e.g., C<[:^digit:]> corresponds to C<\D> and under
+C<utf8>, C<\P{IsDigit}>. The Unicode and POSIX character classes can
+be used just like C<\d>, with the exception that POSIX character
+classes can only be used inside of a character class:
+
+ /\s+[abc[:digit:]xyz]\s*/; # match a,b,c,x,y,z, or a digit
+ /^=item\s[[:digit:]]/; # match '=item',
+ # followed by a space and a digit
+ use charnames ":full";
+ /\s+[abc\p{IsDigit}xyz]\s+/; # match a,b,c,x,y,z, or a digit
+ /^=item\s\p{IsDigit}/; # match '=item',
+ # followed by a space and a digit
+
+Whew! That is all the rest of the characters and character classes.
+
+=head2 Compiling and saving regular expressions
+
+In Part 1 we discussed the C<//o> modifier, which compiles a regexp
+just once. This suggests that a compiled regexp is some data structure
+that can be stored once and used again and again. The regexp quote
+C<qr//> does exactly that: C<qr/string/> compiles the C<string> as a
+regexp and transforms the result into a form that can be assigned to a
+variable:
+
+ $reg = qr/foo+bar?/; # reg contains a compiled regexp
+
+Then C<$reg> can be used as a regexp:
+
+ $x = "fooooba";
+ $x =~ $reg; # matches, just like /foo+bar?/
+ $x =~ /$reg/; # same thing, alternate form
+
+C<$reg> can also be interpolated into a larger regexp:
+
+ $x =~ /(abc)?$reg/; # still matches
+
+As with the matching operator, the regexp quote can use different
+delimiters, e.g., C<qr!!>, C<qr{}> or C<qr~~>. Apostrophes
+as delimiters (C<qr''>) inhibit any interpolation.
+
+Pre-compiled regexps are useful for creating dynamic matches that
+don't need to be recompiled each time they are encountered. Using
+pre-compiled regexps, we write a C<grep_step> program which greps
+for a sequence of patterns, advancing to the next pattern as soon
+as one has been satisfied.
+
+ % cat > grep_step
+ #!/usr/bin/perl
+ # grep_step - match <number> regexps, one after the other
+ # usage: multi_grep <number> regexp1 regexp2 ... file1 file2 ...
+
+ $number = shift;
+ $regexp[$_] = shift foreach (0..$number-1);
+ @compiled = map qr/$_/, @regexp;
+ while ($line = <>) {
+ if ($line =~ /$compiled[0]/) {
+ print $line;
+ shift @compiled;
+ last unless @compiled;
+ }
+ }
+ ^D
+
+ % grep_step 3 shift print last grep_step
+ $number = shift;
+ print $line;
+ last unless @compiled;
+
+Storing pre-compiled regexps in an array C<@compiled> allows us to
+simply loop through the regexps without any recompilation, thus gaining
+flexibility without sacrificing speed.
+
+
+=head2 Composing regular expressions at runtime
+
+Backtracking is more efficient than repeated tries with different regular
+expressions. If there are several regular expressions and a match with
+any of them is acceptable, then it is possible to combine them into a set
+of alternatives. If the individual expressions are input data, this
+can be done by programming a join operation. We'll exploit this idea in
+an improved version of the C<simple_grep> program: a program that matches
+multiple patterns:
+
+ % cat > multi_grep
+ #!/usr/bin/perl
+ # multi_grep - match any of <number> regexps
+ # usage: multi_grep <number> regexp1 regexp2 ... file1 file2 ...
+
+ $number = shift;
+ $regexp[$_] = shift foreach (0..$number-1);
+ $pattern = join '|', @regexp;
+
+ while ($line = <>) {
+ print $line if $line =~ /$pattern/o;
+ }
+ ^D
+
+ % multi_grep 2 shift for multi_grep
+ $number = shift;
+ $regexp[$_] = shift foreach (0..$number-1);
+
+Sometimes it is advantageous to construct a pattern from the I<input>
+that is to be analyzed and use the permissible values on the left
+hand side of the matching operations. As an example for this somewhat
+paradoxical situation, let's assume that our input contains a command
+verb which should match one out of a set of available command verbs,
+with the additional twist that commands may be abbreviated as long as
+the given string is unique. The program below demonstrates the basic
+algorithm.
+
+ % cat > keymatch
+ #!/usr/bin/perl
+ $kwds = 'copy compare list print';
+ while( $command = <> ){
+ $command =~ s/^\s+|\s+$//g; # trim leading and trailing spaces
+ if( ( @matches = $kwds =~ /\b$command\w*/g ) == 1 ){
+ print "command: '@matches'\n";
+ } elsif( @matches == 0 ){
+ print "no such command: '$command'\n";
+ } else {
+ print "not unique: '$command' (could be one of: @matches)\n";
+ }
+ }
+ ^D
+
+ % keymatch
+ li
+ command: 'list'
+ co
+ not unique: 'co' (could be one of: copy compare)
+ printer
+ no such command: 'printer'
+
+Rather than trying to match the input against the keywords, we match the
+combined set of keywords against the input. The pattern matching
+operation S<C<$kwds =~ /\b($command\w*)/g>> does several things at the
+same time. It makes sure that the given command begins where a keyword
+begins (C<\b>). It tolerates abbreviations due to the added C<\w*>. It
+tells us the number of matches (C<scalar @matches>) and all the keywords
+that were actually matched. You could hardly ask for more.
+
+=head2 Embedding comments and modifiers in a regular expression
+
+Starting with this section, we will be discussing Perl's set of
+I<extended patterns>. These are extensions to the traditional regular
+expression syntax that provide powerful new tools for pattern
+matching. We have already seen extensions in the form of the minimal
+matching constructs C<??>, C<*?>, C<+?>, C<{n,m}?>, and C<{n,}?>. The
+rest of the extensions below have the form C<(?char...)>, where the
+C<char> is a character that determines the type of extension.
+
+The first extension is an embedded comment C<(?#text)>. This embeds a
+comment into the regular expression without affecting its meaning. The
+comment should not have any closing parentheses in the text. An
+example is
+
+ /(?# Match an integer:)[+-]?\d+/;
+
+This style of commenting has been largely superseded by the raw,
+freeform commenting that is allowed with the C<//x> modifier.
+
+The modifiers C<//i>, C<//m>, C<//s> and C<//x> (or any
+combination thereof) can also be embedded in
+a regexp using C<(?i)>, C<(?m)>, C<(?s)>, and C<(?x)>. For instance,
+
+ /(?i)yes/; # match 'yes' case insensitively
+ /yes/i; # same thing
+ /(?x)( # freeform version of an integer regexp
+ [+-]? # match an optional sign
+ \d+ # match a sequence of digits
+ )
+ /x;
+
+Embedded modifiers can have two important advantages over the usual
+modifiers. Embedded modifiers allow a custom set of modifiers to
+I<each> regexp pattern. This is great for matching an array of regexps
+that must have different modifiers:
+
+ $pattern[0] = '(?i)doctor';
+ $pattern[1] = 'Johnson';
+ ...
+ while (<>) {
+ foreach $patt (@pattern) {
+ print if /$patt/;
+ }
+ }
+
+The second advantage is that embedded modifiers (except C<//p>, which
+modifies the entire regexp) only affect the regexp
+inside the group the embedded modifier is contained in. So grouping
+can be used to localize the modifier's effects:
+
+ /Answer: ((?i)yes)/; # matches 'Answer: yes', 'Answer: YES', etc.
+
+Embedded modifiers can also turn off any modifiers already present
+by using, e.g., C<(?-i)>. Modifiers can also be combined into
+a single expression, e.g., C<(?s-i)> turns on single line mode and
+turns off case insensitivity.
+
+Embedded modifiers may also be added to a non-capturing grouping.
+C<(?i-m:regexp)> is a non-capturing grouping that matches C<regexp>
+case insensitively and turns off multi-line mode.
+
+
+=head2 Looking ahead and looking behind
+
+This section concerns the lookahead and lookbehind assertions. First,
+a little background.
+
+In Perl regular expressions, most regexp elements 'eat up' a certain
+amount of string when they match. For instance, the regexp element
+C<[abc}]> eats up one character of the string when it matches, in the
+sense that Perl moves to the next character position in the string
+after the match. There are some elements, however, that don't eat up
+characters (advance the character position) if they match. The examples
+we have seen so far are the anchors. The anchor C<^> matches the
+beginning of the line, but doesn't eat any characters. Similarly, the
+word boundary anchor C<\b> matches wherever a character matching C<\w>
+is next to a character that doesn't, but it doesn't eat up any
+characters itself. Anchors are examples of I<zero-width assertions>.
+Zero-width, because they consume
+no characters, and assertions, because they test some property of the
+string. In the context of our walk in the woods analogy to regexp
+matching, most regexp elements move us along a trail, but anchors have
+us stop a moment and check our surroundings. If the local environment
+checks out, we can proceed forward. But if the local environment
+doesn't satisfy us, we must backtrack.
+
+Checking the environment entails either looking ahead on the trail,
+looking behind, or both. C<^> looks behind, to see that there are no
+characters before. C<$> looks ahead, to see that there are no
+characters after. C<\b> looks both ahead and behind, to see if the
+characters on either side differ in their "word-ness".
+
+The lookahead and lookbehind assertions are generalizations of the
+anchor concept. Lookahead and lookbehind are zero-width assertions
+that let us specify which characters we want to test for. The
+lookahead assertion is denoted by C<(?=regexp)> and the lookbehind
+assertion is denoted by C<< (?<=fixed-regexp) >>. Some examples are
+
+ $x = "I catch the housecat 'Tom-cat' with catnip";
+ $x =~ /cat(?=\s)/; # matches 'cat' in 'housecat'
+ @catwords = ($x =~ /(?<=\s)cat\w+/g); # matches,
+ # $catwords[0] = 'catch'
+ # $catwords[1] = 'catnip'
+ $x =~ /\bcat\b/; # matches 'cat' in 'Tom-cat'
+ $x =~ /(?<=\s)cat(?=\s)/; # doesn't match; no isolated 'cat' in
+ # middle of $x
+
+Note that the parentheses in C<(?=regexp)> and C<< (?<=regexp) >> are
+non-capturing, since these are zero-width assertions. Thus in the
+second regexp, the substrings captured are those of the whole regexp
+itself. Lookahead C<(?=regexp)> can match arbitrary regexps, but
+lookbehind C<< (?<=fixed-regexp) >> only works for regexps of fixed
+width, i.e., a fixed number of characters long. Thus
+C<< (?<=(ab|bc)) >> is fine, but C<< (?<=(ab)*) >> is not. The
+negated versions of the lookahead and lookbehind assertions are
+denoted by C<(?!regexp)> and C<< (?<!fixed-regexp) >> respectively.
+They evaluate true if the regexps do I<not> match:
+
+ $x = "foobar";
+ $x =~ /foo(?!bar)/; # doesn't match, 'bar' follows 'foo'
+ $x =~ /foo(?!baz)/; # matches, 'baz' doesn't follow 'foo'
+ $x =~ /(?<!\s)foo/; # matches, there is no \s before 'foo'
+
+The C<\C> is unsupported in lookbehind, because the already
+treacherous definition of C<\C> would become even more so
+when going backwards.
+
+Here is an example where a string containing blank-separated words,
+numbers and single dashes is to be split into its components.
+Using C</\s+/> alone won't work, because spaces are not required between
+dashes, or a word or a dash. Additional places for a split are established
+by looking ahead and behind:
+
+ $str = "one two - --6-8";
+ @toks = split / \s+ # a run of spaces
+ | (?<=\S) (?=-) # any non-space followed by '-'
+ | (?<=-) (?=\S) # a '-' followed by any non-space
+ /x, $str; # @toks = qw(one two - - - 6 - 8)
+
+
+=head2 Using independent subexpressions to prevent backtracking
+
+I<Independent subexpressions> are regular expressions, in the
+context of a larger regular expression, that function independently of
+the larger regular expression. That is, they consume as much or as
+little of the string as they wish without regard for the ability of
+the larger regexp to match. Independent subexpressions are represented
+by C<< (?>regexp) >>. We can illustrate their behavior by first
+considering an ordinary regexp:
+
+ $x = "ab";
+ $x =~ /a*ab/; # matches
+
+This obviously matches, but in the process of matching, the
+subexpression C<a*> first grabbed the C<a>. Doing so, however,
+wouldn't allow the whole regexp to match, so after backtracking, C<a*>
+eventually gave back the C<a> and matched the empty string. Here, what
+C<a*> matched was I<dependent> on what the rest of the regexp matched.
+
+Contrast that with an independent subexpression:
+
+ $x =~ /(?>a*)ab/; # doesn't match!
+
+The independent subexpression C<< (?>a*) >> doesn't care about the rest
+of the regexp, so it sees an C<a> and grabs it. Then the rest of the
+regexp C<ab> cannot match. Because C<< (?>a*) >> is independent, there
+is no backtracking and the independent subexpression does not give
+up its C<a>. Thus the match of the regexp as a whole fails. A similar
+behavior occurs with completely independent regexps:
+
+ $x = "ab";
+ $x =~ /a*/g; # matches, eats an 'a'
+ $x =~ /\Gab/g; # doesn't match, no 'a' available
+
+Here C<//g> and C<\G> create a 'tag team' handoff of the string from
+one regexp to the other. Regexps with an independent subexpression are
+much like this, with a handoff of the string to the independent
+subexpression, and a handoff of the string back to the enclosing
+regexp.
+
+The ability of an independent subexpression to prevent backtracking
+can be quite useful. Suppose we want to match a non-empty string
+enclosed in parentheses up to two levels deep. Then the following
+regexp matches:
+
+ $x = "abc(de(fg)h"; # unbalanced parentheses
+ $x =~ /\( ( [^()]+ | \([^()]*\) )+ \)/x;
+
+The regexp matches an open parenthesis, one or more copies of an
+alternation, and a close parenthesis. The alternation is two-way, with
+the first alternative C<[^()]+> matching a substring with no
+parentheses and the second alternative C<\([^()]*\)> matching a
+substring delimited by parentheses. The problem with this regexp is
+that it is pathological: it has nested indeterminate quantifiers
+of the form C<(a+|b)+>. We discussed in Part 1 how nested quantifiers
+like this could take an exponentially long time to execute if there
+was no match possible. To prevent the exponential blowup, we need to
+prevent useless backtracking at some point. This can be done by
+enclosing the inner quantifier as an independent subexpression:
+
+ $x =~ /\( ( (?>[^()]+) | \([^()]*\) )+ \)/x;
+
+Here, C<< (?>[^()]+) >> breaks the degeneracy of string partitioning
+by gobbling up as much of the string as possible and keeping it. Then
+match failures fail much more quickly.
+
+
+=head2 Conditional expressions
+
+A I<conditional expression> is a form of if-then-else statement
+that allows one to choose which patterns are to be matched, based on
+some condition. There are two types of conditional expression:
+C<(?(condition)yes-regexp)> and
+C<(?(condition)yes-regexp|no-regexp)>. C<(?(condition)yes-regexp)> is
+like an S<C<'if () {}'>> statement in Perl. If the C<condition> is true,
+the C<yes-regexp> will be matched. If the C<condition> is false, the
+C<yes-regexp> will be skipped and Perl will move onto the next regexp
+element. The second form is like an S<C<'if () {} else {}'>> statement
+in Perl. If the C<condition> is true, the C<yes-regexp> will be
+matched, otherwise the C<no-regexp> will be matched.
+
+The C<condition> can have several forms. The first form is simply an
+integer in parentheses C<(integer)>. It is true if the corresponding
+backreference C<\integer> matched earlier in the regexp. The same
+thing can be done with a name associated with a capture buffer, written
+as C<< (<name>) >> or C<< ('name') >>. The second form is a bare
+zero width assertion C<(?...)>, either a lookahead, a lookbehind, or a
+code assertion (discussed in the next section). The third set of forms
+provides tests that return true if the expression is executed within
+a recursion (C<(R)>) or is being called from some capturing group,
+referenced either by number (C<(R1)>, C<(R2)>,...) or by name
+(C<(R&name)>).
+
+The integer or name form of the C<condition> allows us to choose,
+with more flexibility, what to match based on what matched earlier in the
+regexp. This searches for words of the form C<"$x$x"> or C<"$x$y$y$x">:
+
+ % simple_grep '^(\w+)(\w+)?(?(2)\2\1|\1)$' /usr/dict/words
+ beriberi
+ coco
+ couscous
+ deed
+ ...
+ toot
+ toto
+ tutu
+
+The lookbehind C<condition> allows, along with backreferences,
+an earlier part of the match to influence a later part of the
+match. For instance,
+
+ /[ATGC]+(?(?<=AA)G|C)$/;
+
+matches a DNA sequence such that it either ends in C<AAG>, or some
+other base pair combination and C<C>. Note that the form is
+C<< (?(?<=AA)G|C) >> and not C<< (?((?<=AA))G|C) >>; for the
+lookahead, lookbehind or code assertions, the parentheses around the
+conditional are not needed.
+
+
+=head2 Defining named patterns
+
+Some regular expressions use identical subpatterns in several places.
+Starting with Perl 5.10, it is possible to define named subpatterns in
+a section of the pattern so that they can be called up by name
+anywhere in the pattern. This syntactic pattern for this definition
+group is C<< (?(DEFINE)(?<name>pattern)...) >>. An insertion
+of a named pattern is written as C<(?&name)>.
+
+The example below illustrates this feature using the pattern for
+floating point numbers that was presented earlier on. The three
+subpatterns that are used more than once are the optional sign, the
+digit sequence for an integer and the decimal fraction. The DEFINE
+group at the end of the pattern contains their definition. Notice
+that the decimal fraction pattern is the first place where we can
+reuse the integer pattern.
+
+ /^ (?&osg)\ * ( (?&int)(?&dec)? | (?&dec) )
+ (?: [eE](?&osg)(?&int) )?
+ $
+ (?(DEFINE)
+ (?<osg>[-+]?) # optional sign
+ (?<int>\d++) # integer
+ (?<dec>\.(?&int)) # decimal fraction
+ )/x
+
+
+=head2 Recursive patterns
+
+This feature (introduced in Perl 5.10) significantly extends the
+power of Perl's pattern matching. By referring to some other
+capture group anywhere in the pattern with the construct
+C<(?group-ref)>, the I<pattern> within the referenced group is used
+as an independent subpattern in place of the group reference itself.
+Because the group reference may be contained I<within> the group it
+refers to, it is now possible to apply pattern matching to tasks that
+hitherto required a recursive parser.
+
+To illustrate this feature, we'll design a pattern that matches if
+a string contains a palindrome. (This is a word or a sentence that,
+while ignoring spaces, interpunctuation and case, reads the same backwards
+as forwards. We begin by observing that the empty string or a string
+containing just one word character is a palindrome. Otherwise it must
+have a word character up front and the same at its end, with another
+palindrome in between.
+
+ /(?: (\w) (?...Here be a palindrome...) \g{-1} | \w? )/x
+
+Adding C<\W*> at either end to eliminate what is to be ignored, we already
+have the full pattern:
+
+ my $pp = qr/^(\W* (?: (\w) (?1) \g{-1} | \w? ) \W*)$/ix;
+ for $s ( "saippuakauppias", "A man, a plan, a canal: Panama!" ){
+ print "'$s' is a palindrome\n" if $s =~ /$pp/;
+ }
+
+In C<(?...)> both absolute and relative backreferences may be used.
+The entire pattern can be reinserted with C<(?R)> or C<(?0)>.
+If you prefer to name your buffers, you can use C<(?&name)> to
+recurse into that buffer.
+
+
+=head2 A bit of magic: executing Perl code in a regular expression
+
+Normally, regexps are a part of Perl expressions.
+I<Code evaluation> expressions turn that around by allowing
+arbitrary Perl code to be a part of a regexp. A code evaluation
+expression is denoted C<(?{code})>, with I<code> a string of Perl
+statements.
+
+Be warned that this feature is considered experimental, and may be
+changed without notice.
+
+Code expressions are zero-width assertions, and the value they return
+depends on their environment. There are two possibilities: either the
+code expression is used as a conditional in a conditional expression
+C<(?(condition)...)>, or it is not. If the code expression is a
+conditional, the code is evaluated and the result (i.e., the result of
+the last statement) is used to determine truth or falsehood. If the
+code expression is not used as a conditional, the assertion always
+evaluates true and the result is put into the special variable
+C<$^R>. The variable C<$^R> can then be used in code expressions later
+in the regexp. Here are some silly examples:
+
+ $x = "abcdef";
+ $x =~ /abc(?{print "Hi Mom!";})def/; # matches,
+ # prints 'Hi Mom!'
+ $x =~ /aaa(?{print "Hi Mom!";})def/; # doesn't match,
+ # no 'Hi Mom!'
+
+Pay careful attention to the next example:
+
+ $x =~ /abc(?{print "Hi Mom!";})ddd/; # doesn't match,
+ # no 'Hi Mom!'
+ # but why not?
+
+At first glance, you'd think that it shouldn't print, because obviously
+the C<ddd> isn't going to match the target string. But look at this
+example:
+
+ $x =~ /abc(?{print "Hi Mom!";})[dD]dd/; # doesn't match,
+ # but _does_ print
+
+Hmm. What happened here? If you've been following along, you know that
+the above pattern should be effectively (almost) the same as the last one;
+enclosing the C<d> in a character class isn't going to change what it
+matches. So why does the first not print while the second one does?
+
+The answer lies in the optimizations the regex engine makes. In the first
+case, all the engine sees are plain old characters (aside from the
+C<?{}> construct). It's smart enough to realize that the string 'ddd'
+doesn't occur in our target string before actually running the pattern
+through. But in the second case, we've tricked it into thinking that our
+pattern is more complicated. It takes a look, sees our
+character class, and decides that it will have to actually run the
+pattern to determine whether or not it matches, and in the process of
+running it hits the print statement before it discovers that we don't
+have a match.
+
+To take a closer look at how the engine does optimizations, see the
+section L<"Pragmas and debugging"> below.
+
+More fun with C<?{}>:
+
+ $x =~ /(?{print "Hi Mom!";})/; # matches,
+ # prints 'Hi Mom!'
+ $x =~ /(?{$c = 1;})(?{print "$c";})/; # matches,
+ # prints '1'
+ $x =~ /(?{$c = 1;})(?{print "$^R";})/; # matches,
+ # prints '1'
+
+The bit of magic mentioned in the section title occurs when the regexp
+backtracks in the process of searching for a match. If the regexp
+backtracks over a code expression and if the variables used within are
+localized using C<local>, the changes in the variables produced by the
+code expression are undone! Thus, if we wanted to count how many times
+a character got matched inside a group, we could use, e.g.,
+
+ $x = "aaaa";
+ $count = 0; # initialize 'a' count
+ $c = "bob"; # test if $c gets clobbered
+ $x =~ /(?{local $c = 0;}) # initialize count
+ ( a # match 'a'
+ (?{local $c = $c + 1;}) # increment count
+ )* # do this any number of times,
+ aa # but match 'aa' at the end
+ (?{$count = $c;}) # copy local $c var into $count
+ /x;
+ print "'a' count is $count, \$c variable is '$c'\n";
+
+This prints
+
+ 'a' count is 2, $c variable is 'bob'
+
+If we replace the S<C< (?{local $c = $c + 1;})>> with
+S<C< (?{$c = $c + 1;})>>, the variable changes are I<not> undone
+during backtracking, and we get
+
+ 'a' count is 4, $c variable is 'bob'
+
+Note that only localized variable changes are undone. Other side
+effects of code expression execution are permanent. Thus
+
+ $x = "aaaa";
+ $x =~ /(a(?{print "Yow\n";}))*aa/;
+
+produces
+
+ Yow
+ Yow
+ Yow
+ Yow
+
+The result C<$^R> is automatically localized, so that it will behave
+properly in the presence of backtracking.
+
+This example uses a code expression in a conditional to match a
+definite article, either 'the' in English or 'der|die|das' in German:
+
+ $lang = 'DE'; # use German
+ ...
+ $text = "das";
+ print "matched\n"
+ if $text =~ /(?(?{
+ $lang eq 'EN'; # is the language English?
+ })
+ the | # if so, then match 'the'
+ (der|die|das) # else, match 'der|die|das'
+ )
+ /xi;
+
+Note that the syntax here is C<(?(?{...})yes-regexp|no-regexp)>, not
+C<(?((?{...}))yes-regexp|no-regexp)>. In other words, in the case of a
+code expression, we don't need the extra parentheses around the
+conditional.
+
+If you try to use code expressions with interpolating variables, Perl
+may surprise you:
+
+ $bar = 5;
+ $pat = '(?{ 1 })';
+ /foo(?{ $bar })bar/; # compiles ok, $bar not interpolated
+ /foo(?{ 1 })$bar/; # compile error!
+ /foo${pat}bar/; # compile error!
+
+ $pat = qr/(?{ $foo = 1 })/; # precompile code regexp
+ /foo${pat}bar/; # compiles ok
+
+If a regexp has (1) code expressions and interpolating variables, or
+(2) a variable that interpolates a code expression, Perl treats the
+regexp as an error. If the code expression is precompiled into a
+variable, however, interpolating is ok. The question is, why is this
+an error?
+
+The reason is that variable interpolation and code expressions
+together pose a security risk. The combination is dangerous because
+many programmers who write search engines often take user input and
+plug it directly into a regexp:
+
+ $regexp = <>; # read user-supplied regexp
+ $chomp $regexp; # get rid of possible newline
+ $text =~ /$regexp/; # search $text for the $regexp
+
+If the C<$regexp> variable contains a code expression, the user could
+then execute arbitrary Perl code. For instance, some joker could
+search for S<C<system('rm -rf *');>> to erase your files. In this
+sense, the combination of interpolation and code expressions I<taints>
+your regexp. So by default, using both interpolation and code
+expressions in the same regexp is not allowed. If you're not
+concerned about malicious users, it is possible to bypass this
+security check by invoking S<C<use re 'eval'>>:
+
+ use re 'eval'; # throw caution out the door
+ $bar = 5;
+ $pat = '(?{ 1 })';
+ /foo(?{ 1 })$bar/; # compiles ok
+ /foo${pat}bar/; # compiles ok
+
+Another form of code expression is the I<pattern code expression>.
+The pattern code expression is like a regular code expression, except
+that the result of the code evaluation is treated as a regular
+expression and matched immediately. A simple example is
+
+ $length = 5;
+ $char = 'a';
+ $x = 'aaaaabb';
+ $x =~ /(??{$char x $length})/x; # matches, there are 5 of 'a'
+
+
+This final example contains both ordinary and pattern code
+expressions. It detects whether a binary string C<1101010010001...> has a
+Fibonacci spacing 0,1,1,2,3,5,... of the C<1>'s:
+
+ $x = "1101010010001000001";
+ $z0 = ''; $z1 = '0'; # initial conditions
+ print "It is a Fibonacci sequence\n"
+ if $x =~ /^1 # match an initial '1'
+ (?:
+ ((??{ $z0 })) # match some '0'
+ 1 # and then a '1'
+ (?{ $z0 = $z1; $z1 .= $^N; })
+ )+ # repeat as needed
+ $ # that is all there is
+ /x;
+ printf "Largest sequence matched was %d\n", length($z1)-length($z0);
+
+Remember that C<$^N> is set to whatever was matched by the last
+completed capture group. This prints
+
+ It is a Fibonacci sequence
+ Largest sequence matched was 5
+
+Ha! Try that with your garden variety regexp package...
+
+Note that the variables C<$z0> and C<$z1> are not substituted when the
+regexp is compiled, as happens for ordinary variables outside a code
+expression. Rather, the code expressions are evaluated when Perl
+encounters them during the search for a match.
+
+The regexp without the C<//x> modifier is
+
+ /^1(?:((??{ $z0 }))1(?{ $z0 = $z1; $z1 .= $^N; }))+$/
+
+which shows that spaces are still possible in the code parts. Nevertheless,
+when working with code and conditional expressions, the extended form of
+regexps is almost necessary in creating and debugging regexps.
+
+
+=head2 Backtracking control verbs
+
+Perl 5.10 introduced a number of control verbs intended to provide
+detailed control over the backtracking process, by directly influencing
+the regexp engine and by providing monitoring techniques. As all
+the features in this group are experimental and subject to change or
+removal in a future version of Perl, the interested reader is
+referred to L<perlre/"Special Backtracking Control Verbs"> for a
+detailed description.
+
+Below is just one example, illustrating the control verb C<(*FAIL)>,
+which may be abbreviated as C<(*F)>. If this is inserted in a regexp
+it will cause to fail, just like at some mismatch between the pattern
+and the string. Processing of the regexp continues like after any "normal"
+failure, so that, for instance, the next position in the string or another
+alternative will be tried. As failing to match doesn't preserve capture
+buffers or produce results, it may be necessary to use this in
+combination with embedded code.
+
+ %count = ();
+ "supercalifragilisticexpialidoceous" =~
+ /([aeiou])(?{ $count{$1}++; })(*FAIL)/oi;
+ printf "%3d '%s'\n", $count{$_}, $_ for (sort keys %count);
+
+The pattern begins with a class matching a subset of letters. Whenever
+this matches, a statement like C<$count{'a'}++;> is executed, incrementing
+the letter's counter. Then C<(*FAIL)> does what it says, and
+the regexp engine proceeds according to the book: as long as the end of
+the string hasn't been reached, the position is advanced before looking
+for another vowel. Thus, match or no match makes no difference, and the
+regexp engine proceeds until the entire string has been inspected.
+(It's remarkable that an alternative solution using something like
+
+ $count{lc($_)}++ for split('', "supercalifragilisticexpialidoceous");
+ printf "%3d '%s'\n", $count2{$_}, $_ for ( qw{ a e i o u } );
+
+is considerably slower.)
+
+
+=head2 Pragmas and debugging
+
+Speaking of debugging, there are several pragmas available to control
+and debug regexps in Perl. We have already encountered one pragma in
+the previous section, S<C<use re 'eval';>>, that allows variable
+interpolation and code expressions to coexist in a regexp. The other
+pragmas are
+
+ use re 'taint';
+ $tainted = <>;
+ @parts = ($tainted =~ /(\w+)\s+(\w+)/; # @parts is now tainted
+
+The C<taint> pragma causes any substrings from a match with a tainted
+variable to be tainted as well. This is not normally the case, as
+regexps are often used to extract the safe bits from a tainted
+variable. Use C<taint> when you are not extracting safe bits, but are
+performing some other processing. Both C<taint> and C<eval> pragmas
+are lexically scoped, which means they are in effect only until
+the end of the block enclosing the pragmas.
+
+ use re 'debug';
+ /^(.*)$/s; # output debugging info
+
+ use re 'debugcolor';
+ /^(.*)$/s; # output debugging info in living color
+
+The global C<debug> and C<debugcolor> pragmas allow one to get
+detailed debugging info about regexp compilation and
+execution. C<debugcolor> is the same as debug, except the debugging
+information is displayed in color on terminals that can display
+termcap color sequences. Here is example output:
+
+ % perl -e 'use re "debug"; "abc" =~ /a*b+c/;'
+ Compiling REx `a*b+c'
+ size 9 first at 1
+ 1: STAR(4)
+ 2: EXACT <a>(0)
+ 4: PLUS(7)
+ 5: EXACT <b>(0)
+ 7: EXACT <c>(9)
+ 9: END(0)
+ floating `bc' at 0..2147483647 (checking floating) minlen 2
+ Guessing start of match, REx `a*b+c' against `abc'...
+ Found floating substr `bc' at offset 1...
+ Guessed: match at offset 0
+ Matching REx `a*b+c' against `abc'
+ Setting an EVAL scope, savestack=3
+ 0 <> <abc> | 1: STAR
+ EXACT <a> can match 1 times out of 32767...
+ Setting an EVAL scope, savestack=3
+ 1 <a> <bc> | 4: PLUS
+ EXACT <b> can match 1 times out of 32767...
+ Setting an EVAL scope, savestack=3
+ 2 <ab> <c> | 7: EXACT <c>
+ 3 <abc> <> | 9: END
+ Match successful!
+ Freeing REx: `a*b+c'
+
+If you have gotten this far into the tutorial, you can probably guess
+what the different parts of the debugging output tell you. The first
+part
+
+ Compiling REx `a*b+c'
+ size 9 first at 1
+ 1: STAR(4)
+ 2: EXACT <a>(0)
+ 4: PLUS(7)
+ 5: EXACT <b>(0)
+ 7: EXACT <c>(9)
+ 9: END(0)
+
+describes the compilation stage. C<STAR(4)> means that there is a
+starred object, in this case C<'a'>, and if it matches, goto line 4,
+i.e., C<PLUS(7)>. The middle lines describe some heuristics and
+optimizations performed before a match:
+
+ floating `bc' at 0..2147483647 (checking floating) minlen 2
+ Guessing start of match, REx `a*b+c' against `abc'...
+ Found floating substr `bc' at offset 1...
+ Guessed: match at offset 0
+
+Then the match is executed and the remaining lines describe the
+process:
+
+ Matching REx `a*b+c' against `abc'
+ Setting an EVAL scope, savestack=3
+ 0 <> <abc> | 1: STAR
+ EXACT <a> can match 1 times out of 32767...
+ Setting an EVAL scope, savestack=3
+ 1 <a> <bc> | 4: PLUS
+ EXACT <b> can match 1 times out of 32767...
+ Setting an EVAL scope, savestack=3
+ 2 <ab> <c> | 7: EXACT <c>
+ 3 <abc> <> | 9: END
+ Match successful!
+ Freeing REx: `a*b+c'
+
+Each step is of the form S<C<< n <x> <y> >>>, with C<< <x> >> the
+part of the string matched and C<< <y> >> the part not yet
+matched. The S<C<< | 1: STAR >>> says that Perl is at line number 1
+n the compilation list above. See
+L<perldebguts/"Debugging regular expressions"> for much more detail.
+
+An alternative method of debugging regexps is to embed C<print>
+statements within the regexp. This provides a blow-by-blow account of
+the backtracking in an alternation:
+
+ "that this" =~ m@(?{print "Start at position ", pos, "\n";})
+ t(?{print "t1\n";})
+ h(?{print "h1\n";})
+ i(?{print "i1\n";})
+ s(?{print "s1\n";})
+ |
+ t(?{print "t2\n";})
+ h(?{print "h2\n";})
+ a(?{print "a2\n";})
+ t(?{print "t2\n";})
+ (?{print "Done at position ", pos, "\n";})
+ @x;
+
+prints
+
+ Start at position 0
+ t1
+ h1
+ t2
+ h2
+ a2
+ t2
+ Done at position 4
+
+=head1 BUGS
+
+Code expressions, conditional expressions, and independent expressions
+are I<experimental>. Don't use them in production code. Yet.
+
+=head1 SEE ALSO
+
+This is just a tutorial. For the full story on Perl regular
+expressions, see the L<perlre> regular expressions reference page.
+
+For more information on the matching C<m//> and substitution C<s///>
+operators, see L<perlop/"Regexp Quote-Like Operators">. For
+information on the C<split> operation, see L<perlfunc/split>.
+
+For an excellent all-around resource on the care and feeding of
+regular expressions, see the book I<Mastering Regular Expressions> by
+Jeffrey Friedl (published by O'Reilly, ISBN 1556592-257-3).
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 2000 Mark Kvale
+All rights reserved.
+
+This document may be distributed under the same terms as Perl itself.
+
+=head2 Acknowledgments
+
+The inspiration for the stop codon DNA example came from the ZIP
+code example in chapter 7 of I<Mastering Regular Expressions>.
+
+The author would like to thank Jeff Pinyan, Andrew Johnson, Peter
+Haworth, Ronald J Kimball, and Joe Smith for all their helpful
+comments.
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlriscos.pod b/Master/tlpkg/tlperl/lib/pods/perlriscos.pod
new file mode 100644
index 00000000000..93c365bf654
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlriscos.pod
@@ -0,0 +1,67 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.riscos - Perl version 5 for RISC OS
+
+=head1 DESCRIPTION
+
+This document gives instructions for building Perl for RISC OS. It is
+complicated by the need to cross compile. There is a binary version of
+perl available from L<http://www.cp15.org/perl/> which you may wish to
+use instead of trying to compile it yourself.
+
+=head1 BUILD
+
+You need an installed and working gccsdk cross compiler
+L<http://gccsdk.riscos.info/> and REXEN
+L<http://www.cp15.org/programming/>
+
+Firstly, copy the source and build a native copy of perl for your host
+system.
+Then, in the source to be cross compiled:
+
+=over 4
+
+=item
+
+ $ ./Configure
+
+=item
+
+Select the riscos hint file. The default answers for the rest of the
+questions are usually sufficient.
+
+Note that, if you wish to run Configure non-interactively (see the INSTALL
+document for details), to have it select the correct hint file, you'll
+need to provide the argument -Dhintfile=riscos on the Configure
+command-line.
+
+=item
+
+ $ make miniperl
+
+=item
+
+This should build miniperl and then fail when it tries to run it.
+
+=item
+
+Copy the miniperl executable from the native build done earlier to
+replace the cross compiled miniperl.
+
+=item
+
+ $ make
+
+=item
+
+This will use miniperl to complete the rest of the build.
+
+=back
+
+=head1 AUTHOR
+
+Alex Waugh <alex@alexwaugh.com>
diff --git a/Master/tlpkg/tlperl/lib/pods/perlrun.pod b/Master/tlpkg/tlperl/lib/pods/perlrun.pod
new file mode 100644
index 00000000000..75e7ce10097
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlrun.pod
@@ -0,0 +1,1332 @@
+=head1 NAME
+
+perlrun - how to execute the Perl interpreter
+
+=head1 SYNOPSIS
+
+B<perl> S<[ B<-sTtuUWX> ]>
+ S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
+ S<[ B<-cw> ] [ B<-d>[B<t>][:I<debugger>] ] [ B<-D>[I<number/list>] ]>
+ S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
+ S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]>
+ S<[ B<-C [I<number/list>] >]>
+ S<[ B<-S> ]>
+ S<[ B<-x>[I<dir>] ]>
+ S<[ B<-i>[I<extension>] ]>
+ S<[ [B<-e>|B<-E>] I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
+
+=head1 DESCRIPTION
+
+The normal way to run a Perl program is by making it directly
+executable, or else by passing the name of the source file as an
+argument on the command line. (An interactive Perl environment
+is also possible--see L<perldebug> for details on how to do that.)
+Upon startup, Perl looks for your program in one of the following
+places:
+
+=over 4
+
+=item 1.
+
+Specified line by line via B<-e> or B<-E> switches on the command line.
+
+=item 2.
+
+Contained in the file specified by the first filename on the command line.
+(Note that systems supporting the #! notation invoke interpreters this
+way. See L<Location of Perl>.)
+
+=item 3.
+
+Passed in implicitly via standard input. This works only if there are
+no filename arguments--to pass arguments to a STDIN-read program you
+must explicitly specify a "-" for the program name.
+
+=back
+
+With methods 2 and 3, Perl starts parsing the input file from the
+beginning, unless you've specified a B<-x> switch, in which case it
+scans for the first line starting with #! and containing the word
+"perl", and starts there instead. This is useful for running a program
+embedded in a larger message. (In this case you would indicate the end
+of the program using the C<__END__> token.)
+
+The #! line is always examined for switches as the line is being
+parsed. Thus, if you're on a machine that allows only one argument
+with the #! line, or worse, doesn't even recognize the #! line, you
+still can get consistent switch behavior regardless of how Perl was
+invoked, even if B<-x> was used to find the beginning of the program.
+
+Because historically some operating systems silently chopped off
+kernel interpretation of the #! line after 32 characters, some
+switches may be passed in on the command line, and some may not;
+you could even get a "-" without its letter, if you're not careful.
+You probably want to make sure that all your switches fall either
+before or after that 32-character boundary. Most switches don't
+actually care if they're processed redundantly, but getting a "-"
+instead of a complete switch could cause Perl to try to execute
+standard input instead of your program. And a partial B<-I> switch
+could also cause odd results.
+
+Some switches do care if they are processed twice, for instance
+combinations of B<-l> and B<-0>. Either put all the switches after
+the 32-character boundary (if applicable), or replace the use of
+B<-0>I<digits> by C<BEGIN{ $/ = "\0digits"; }>.
+
+Parsing of the #! switches starts wherever "perl" is mentioned in the line.
+The sequences "-*" and "- " are specifically ignored so that you could,
+if you were so inclined, say
+
+ #!/bin/sh
+ #! -*-perl-*-
+ eval 'exec perl -x -wS $0 ${1+"$@"}'
+ if 0;
+
+to let Perl see the B<-p> switch.
+
+A similar trick involves the B<env> program, if you have it.
+
+ #!/usr/bin/env perl
+
+The examples above use a relative path to the perl interpreter,
+getting whatever version is first in the user's path. If you want
+a specific version of Perl, say, perl5.005_57, you should place
+that directly in the #! line's path.
+
+If the #! line does not contain the word "perl", the program named after
+the #! is executed instead of the Perl interpreter. This is slightly
+bizarre, but it helps people on machines that don't do #!, because they
+can tell a program that their SHELL is F</usr/bin/perl>, and Perl will then
+dispatch the program to the correct interpreter for them.
+
+After locating your program, Perl compiles the entire program to an
+internal form. If there are any compilation errors, execution of the
+program is not attempted. (This is unlike the typical shell script,
+which might run part-way through before finding a syntax error.)
+
+If the program is syntactically correct, it is executed. If the program
+runs off the end without hitting an exit() or die() operator, an implicit
+C<exit(0)> is provided to indicate successful completion.
+
+=head2 #! and quoting on non-Unix systems
+X<hashbang> X<#!>
+
+Unix's #! technique can be simulated on other systems:
+
+=over 4
+
+=item OS/2
+
+Put
+
+ extproc perl -S -your_switches
+
+as the first line in C<*.cmd> file (B<-S> due to a bug in cmd.exe's
+`extproc' handling).
+
+=item MS-DOS
+
+Create a batch file to run your program, and codify it in
+C<ALTERNATE_SHEBANG> (see the F<dosish.h> file in the source
+distribution for more information).
+
+=item Win95/NT
+
+The Win95/NT installation, when using the ActiveState installer for Perl,
+will modify the Registry to associate the F<.pl> extension with the perl
+interpreter. If you install Perl by other means (including building from
+the sources), you may have to modify the Registry yourself. Note that
+this means you can no longer tell the difference between an executable
+Perl program and a Perl library file.
+
+=item VMS
+
+Put
+
+ $ perl -mysw 'f$env("procedure")' 'p1' 'p2' 'p3' 'p4' 'p5' 'p6' 'p7' 'p8' !
+ $ exit++ + ++$status != 0 and $exit = $status = undef;
+
+at the top of your program, where B<-mysw> are any command line switches you
+want to pass to Perl. You can now invoke the program directly, by saying
+C<perl program>, or as a DCL procedure, by saying C<@program> (or implicitly
+via F<DCL$PATH> by just using the name of the program).
+
+This incantation is a bit much to remember, but Perl will display it for
+you if you say C<perl "-V:startperl">.
+
+=back
+
+Command-interpreters on non-Unix systems have rather different ideas
+on quoting than Unix shells. You'll need to learn the special
+characters in your command-interpreter (C<*>, C<\> and C<"> are
+common) and how to protect whitespace and these characters to run
+one-liners (see B<-e> below).
+
+On some systems, you may have to change single-quotes to double ones,
+which you must I<not> do on Unix or Plan 9 systems. You might also
+have to change a single % to a %%.
+
+For example:
+
+ # Unix
+ perl -e 'print "Hello world\n"'
+
+ # MS-DOS, etc.
+ perl -e "print \"Hello world\n\""
+
+ # VMS
+ perl -e "print ""Hello world\n"""
+
+The problem is that none of this is reliable: it depends on the
+command and it is entirely possible neither works. If B<4DOS> were
+the command shell, this would probably work better:
+
+ perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""
+
+B<CMD.EXE> in Windows NT slipped a lot of standard Unix functionality in
+when nobody was looking, but just try to find documentation for its
+quoting rules.
+
+There is no general solution to all of this. It's just a mess.
+
+=head2 Location of Perl
+X<perl, location of interpreter>
+
+It may seem obvious to say, but Perl is useful only when users can
+easily find it. When possible, it's good for both F</usr/bin/perl>
+and F</usr/local/bin/perl> to be symlinks to the actual binary. If
+that can't be done, system administrators are strongly encouraged
+to put (symlinks to) perl and its accompanying utilities into a
+directory typically found along a user's PATH, or in some other
+obvious and convenient place.
+
+In this documentation, C<#!/usr/bin/perl> on the first line of the program
+will stand in for whatever method works on your system. You are
+advised to use a specific path if you care about a specific version.
+
+ #!/usr/local/bin/perl5.00554
+
+or if you just want to be running at least version, place a statement
+like this at the top of your program:
+
+ use 5.005_54;
+
+=head2 Command Switches
+X<perl, command switches> X<command switches>
+
+As with all standard commands, a single-character switch may be
+clustered with the following switch, if any.
+
+ #!/usr/bin/perl -spi.orig # same as -s -p -i.orig
+
+Switches include:
+
+=over 5
+
+=item B<-0>[I<octal/hexadecimal>]
+X<-0> X<$/>
+
+specifies the input record separator (C<$/>) as an octal or
+hexadecimal number. If there are no digits, the null character is the
+separator. Other switches may precede or follow the digits. For
+example, if you have a version of B<find> which can print filenames
+terminated by the null character, you can say this:
+
+ find . -name '*.orig' -print0 | perl -n0e unlink
+
+The special value 00 will cause Perl to slurp files in paragraph mode.
+Any value 0400 or above will cause Perl to slurp files whole, but by convention
+the value 0777 is the one normally used for this purpose.
+
+You can also specify the separator character using hexadecimal notation:
+C<-0xHHH...>, where the C<H> are valid hexadecimal digits. Unlike the octal
+form, this one may be used to specify any Unicode character, even those beyond
+0xFF.
+(This means that you cannot use the C<-x> with a directory name that
+consists of hexadecimal digits.)
+
+=item B<-a>
+X<-a> X<autosplit>
+
+turns on autosplit mode when used with a B<-n> or B<-p>. An implicit
+split command to the @F array is done as the first thing inside the
+implicit while loop produced by the B<-n> or B<-p>.
+
+ perl -ane 'print pop(@F), "\n";'
+
+is equivalent to
+
+ while (<>) {
+ @F = split(' ');
+ print pop(@F), "\n";
+ }
+
+An alternate delimiter may be specified using B<-F>.
+
+=item B<-C [I<number/list>]>
+X<-C>
+
+The C<-C> flag controls some of the Perl Unicode features.
+
+As of 5.8.1, the C<-C> can be followed either by a number or a list
+of option letters. The letters, their numeric values, and effects
+are as follows; listing the letters is equal to summing the numbers.
+
+ I 1 STDIN is assumed to be in UTF-8
+ O 2 STDOUT will be in UTF-8
+ E 4 STDERR will be in UTF-8
+ S 7 I + O + E
+ i 8 UTF-8 is the default PerlIO layer for input streams
+ o 16 UTF-8 is the default PerlIO layer for output streams
+ D 24 i + o
+ A 32 the @ARGV elements are expected to be strings encoded
+ in UTF-8
+ L 64 normally the "IOEioA" are unconditional,
+ the L makes them conditional on the locale environment
+ variables (the LC_ALL, LC_TYPE, and LANG, in the order
+ of decreasing precedence) -- if the variables indicate
+ UTF-8, then the selected "IOEioA" are in effect
+ a 256 Set ${^UTF8CACHE} to -1, to run the UTF-8 caching code in
+ debugging mode.
+
+=for documenting_the_underdocumented
+perl.h gives W/128 as PERL_UNICODE_WIDESYSCALLS "/* for Sarathy */"
+
+=for todo
+perltodo mentions Unicode in %ENV and filenames. I guess that these will be
+options e and f (or F).
+
+For example, C<-COE> and C<-C6> will both turn on UTF-8-ness on both
+STDOUT and STDERR. Repeating letters is just redundant, not cumulative
+nor toggling.
+
+The C<io> options mean that any subsequent open() (or similar I/O
+operations) will have the C<:utf8> PerlIO layer implicitly applied
+to them, in other words, UTF-8 is expected from any input stream,
+and UTF-8 is produced to any output stream. This is just the default,
+with explicit layers in open() and with binmode() one can manipulate
+streams as usual.
+
+C<-C> on its own (not followed by any number or option list), or the
+empty string C<""> for the C<PERL_UNICODE> environment variable, has the
+same effect as C<-CSDL>. In other words, the standard I/O handles and
+the default C<open()> layer are UTF-8-fied B<but> only if the locale
+environment variables indicate a UTF-8 locale. This behaviour follows
+the I<implicit> (and problematic) UTF-8 behaviour of Perl 5.8.0.
+
+You can use C<-C0> (or C<"0"> for C<PERL_UNICODE>) to explicitly
+disable all the above Unicode features.
+
+The read-only magic variable C<${^UNICODE}> reflects the numeric value
+of this setting. This variable is set during Perl startup and is
+thereafter read-only. If you want runtime effects, use the three-arg
+open() (see L<perlfunc/open>), the two-arg binmode() (see L<perlfunc/binmode>),
+and the C<open> pragma (see L<open>).
+
+(In Perls earlier than 5.8.1 the C<-C> switch was a Win32-only switch
+that enabled the use of Unicode-aware "wide system call" Win32 APIs.
+This feature was practically unused, however, and the command line
+switch was therefore "recycled".)
+
+B<Note:> Since perl 5.10.1, if the -C option is used on the #! line, it
+must be specified on the command line as well, since the standard streams
+are already set up at this point in the execution of the perl interpreter.
+You can also use binmode() to set the encoding of an I/O stream.
+
+=item B<-c>
+X<-c>
+
+causes Perl to check the syntax of the program and then exit without
+executing it. Actually, it I<will> execute C<BEGIN>, C<UNITCHECK>,
+C<CHECK>, and C<use> blocks, because these are considered as occurring
+outside the execution of your program. C<INIT> and C<END> blocks,
+however, will be skipped.
+
+=item B<-d>
+X<-d> X<-dt>
+
+=item B<-dt>
+
+runs the program under the Perl debugger. See L<perldebug>.
+If B<t> is specified, it indicates to the debugger that threads
+will be used in the code being debugged.
+
+=item B<-d:>I<foo[=bar,baz]>
+X<-d> X<-dt>
+
+=item B<-dt:>I<foo[=bar,baz]>
+
+runs the program under the control of a debugging, profiling, or
+tracing module installed as Devel::foo. E.g., B<-d:DProf> executes
+the program using the Devel::DProf profiler. As with the B<-M>
+flag, options may be passed to the Devel::foo package where they
+will be received and interpreted by the Devel::foo::import routine.
+The comma-separated list of options must follow a C<=> character.
+If B<t> is specified, it indicates to the debugger that threads
+will be used in the code being debugged.
+See L<perldebug>.
+
+=item B<-D>I<letters>
+X<-D> X<DEBUGGING> X<-DDEBUGGING>
+
+=item B<-D>I<number>
+
+sets debugging flags. To watch how it executes your program, use
+B<-Dtls>. (This works only if debugging is compiled into your
+Perl.) Another nice value is B<-Dx>, which lists your compiled
+syntax tree. And B<-Dr> displays compiled regular expressions;
+the format of the output is explained in L<perldebguts>.
+
+As an alternative, specify a number instead of list of letters (e.g.,
+B<-D14> is equivalent to B<-Dtls>):
+
+ 1 p Tokenizing and parsing (with v, displays parse stack)
+ 2 s Stack snapshots (with v, displays all stacks)
+ 4 l Context (loop) stack processing
+ 8 t Trace execution
+ 16 o Method and overloading resolution
+ 32 c String/numeric conversions
+ 64 P Print profiling info, source file input state
+ 128 m Memory and SV allocation
+ 256 f Format processing
+ 512 r Regular expression parsing and execution
+ 1024 x Syntax tree dump
+ 2048 u Tainting checks
+ 4096 U Unofficial, User hacking (reserved for private, unreleased use)
+ 8192 H Hash dump -- usurps values()
+ 16384 X Scratchpad allocation
+ 32768 D Cleaning up
+ 131072 T Tokenising
+ 262144 R Include reference counts of dumped variables (eg when using -Ds)
+ 524288 J Do not s,t,P-debug (Jump over) opcodes within package DB
+ 1048576 v Verbose: use in conjunction with other flags
+ 2097152 C Copy On Write
+ 4194304 A Consistency checks on internal structures
+ 8388608 q quiet - currently only suppresses the "EXECUTING" message
+ 16777216 M trace smart match resolution
+ 33554432 B dump suBroutine definitions, including special Blocks like BEGIN
+
+All these flags require B<-DDEBUGGING> when you compile the Perl
+executable (but see L<Devel::Peek>, L<re> which may change this).
+See the F<INSTALL> file in the Perl source distribution
+for how to do this. This flag is automatically set if you include B<-g>
+option when C<Configure> asks you about optimizer/debugger flags.
+
+If you're just trying to get a print out of each line of Perl code
+as it executes, the way that C<sh -x> provides for shell scripts,
+you can't use Perl's B<-D> switch. Instead do this
+
+ # If you have "env" utility
+ env PERLDB_OPTS="NonStop=1 AutoTrace=1 frame=2" perl -dS program
+
+ # Bourne shell syntax
+ $ PERLDB_OPTS="NonStop=1 AutoTrace=1 frame=2" perl -dS program
+
+ # csh syntax
+ % (setenv PERLDB_OPTS "NonStop=1 AutoTrace=1 frame=2"; perl -dS program)
+
+See L<perldebug> for details and variations.
+
+=item B<-e> I<commandline>
+X<-e>
+
+may be used to enter one line of program. If B<-e> is given, Perl
+will not look for a filename in the argument list. Multiple B<-e>
+commands may be given to build up a multi-line script. Make sure
+to use semicolons where you would in a normal program.
+
+=item B<-E> I<commandline>
+X<-E>
+
+behaves just like B<-e>, except that it implicitly enables all
+optional features (in the main compilation unit). See L<feature>.
+
+=item B<-f>
+X<-f> X<sitecustomize> X<sitecustomize.pl>
+
+Disable executing F<$Config{sitelib}/sitecustomize.pl> at startup.
+
+Perl can be built so that it by default will try to execute
+F<$Config{sitelib}/sitecustomize.pl> at startup (in a BEGIN block).
+This is a hook that allows the sysadmin to customize how perl behaves.
+It can for instance be used to add entries to the @INC array to make perl
+find modules in non-standard locations.
+
+Perl actually inserts the following code:
+
+ BEGIN {
+ do { local $!; -f "$Config{sitelib}/sitecustomize.pl"; }
+ && do "$Config{sitelib}/sitecustomize.pl";
+ }
+
+Since it is an actual C<do> (not a C<require>), F<sitecustomize.pl>
+doesn't need to return a true value. The code is run in package C<main>,
+in its own lexical scope. However, if the script dies, C<$@> will not
+be set.
+
+The value of C<$Config{sitelib}> is also determined in C code and not
+read from C<Config.pm>, which is not loaded.
+
+The code is executed B<very> early. For example, any changes made to
+C<@INC> will show up in the output of `perl -V`. Of course, C<END>
+blocks will be likewise executed very late.
+
+To determine at runtime if this capability has been compiled in your
+perl, you can check the value of C<$Config{usesitecustomize}>.
+
+=item B<-F>I<pattern>
+X<-F>
+
+specifies the pattern to split on if B<-a> is also in effect. The
+pattern may be surrounded by C<//>, C<"">, or C<''>, otherwise it will be
+put in single quotes. You can't use literal whitespace in the pattern.
+
+=item B<-h>
+X<-h>
+
+prints a summary of the options.
+
+=item B<-i>[I<extension>]
+X<-i> X<in-place>
+
+specifies that files processed by the C<E<lt>E<gt>> construct are to be
+edited in-place. It does this by renaming the input file, opening the
+output file by the original name, and selecting that output file as the
+default for print() statements. The extension, if supplied, is used to
+modify the name of the old file to make a backup copy, following these
+rules:
+
+If no extension is supplied, no backup is made and the current file is
+overwritten.
+
+If the extension doesn't contain a C<*>, then it is appended to the
+end of the current filename as a suffix. If the extension does
+contain one or more C<*> characters, then each C<*> is replaced
+with the current filename. In Perl terms, you could think of this
+as:
+
+ ($backup = $extension) =~ s/\*/$file_name/g;
+
+This allows you to add a prefix to the backup file, instead of (or in
+addition to) a suffix:
+
+ $ perl -pi'orig_*' -e 's/bar/baz/' fileA # backup to 'orig_fileA'
+
+Or even to place backup copies of the original files into another
+directory (provided the directory already exists):
+
+ $ perl -pi'old/*.orig' -e 's/bar/baz/' fileA # backup to 'old/fileA.orig'
+
+These sets of one-liners are equivalent:
+
+ $ perl -pi -e 's/bar/baz/' fileA # overwrite current file
+ $ perl -pi'*' -e 's/bar/baz/' fileA # overwrite current file
+
+ $ perl -pi'.orig' -e 's/bar/baz/' fileA # backup to 'fileA.orig'
+ $ perl -pi'*.orig' -e 's/bar/baz/' fileA # backup to 'fileA.orig'
+
+From the shell, saying
+
+ $ perl -p -i.orig -e "s/foo/bar/; ... "
+
+is the same as using the program:
+
+ #!/usr/bin/perl -pi.orig
+ s/foo/bar/;
+
+which is equivalent to
+
+ #!/usr/bin/perl
+ $extension = '.orig';
+ LINE: while (<>) {
+ if ($ARGV ne $oldargv) {
+ if ($extension !~ /\*/) {
+ $backup = $ARGV . $extension;
+ }
+ else {
+ ($backup = $extension) =~ s/\*/$ARGV/g;
+ }
+ rename($ARGV, $backup);
+ open(ARGVOUT, ">$ARGV");
+ select(ARGVOUT);
+ $oldargv = $ARGV;
+ }
+ s/foo/bar/;
+ }
+ continue {
+ print; # this prints to original filename
+ }
+ select(STDOUT);
+
+except that the B<-i> form doesn't need to compare $ARGV to $oldargv to
+know when the filename has changed. It does, however, use ARGVOUT for
+the selected filehandle. Note that STDOUT is restored as the default
+output filehandle after the loop.
+
+As shown above, Perl creates the backup file whether or not any output
+is actually changed. So this is just a fancy way to copy files:
+
+ $ perl -p -i'/some/file/path/*' -e 1 file1 file2 file3...
+or
+ $ perl -p -i'.orig' -e 1 file1 file2 file3...
+
+You can use C<eof> without parentheses to locate the end of each input
+file, in case you want to append to each file, or reset line numbering
+(see example in L<perlfunc/eof>).
+
+If, for a given file, Perl is unable to create the backup file as
+specified in the extension then it will skip that file and continue on
+with the next one (if it exists).
+
+For a discussion of issues surrounding file permissions and B<-i>,
+see L<perlfaq5/Why does Perl let me delete read-only files? Why does -i clobber protected files? Isn't this a bug in Perl?>.
+
+You cannot use B<-i> to create directories or to strip extensions from
+files.
+
+Perl does not expand C<~> in filenames, which is good, since some
+folks use it for their backup files:
+
+ $ perl -pi~ -e 's/foo/bar/' file1 file2 file3...
+
+Note that because B<-i> renames or deletes the original file before
+creating a new file of the same name, Unix-style soft and hard links will
+not be preserved.
+
+Finally, the B<-i> switch does not impede execution when no
+files are given on the command line. In this case, no backup is made
+(the original file cannot, of course, be determined) and processing
+proceeds from STDIN to STDOUT as might be expected.
+
+=item B<-I>I<directory>
+X<-I> X<@INC>
+
+Directories specified by B<-I> are prepended to the search path for
+modules (C<@INC>).
+
+=item B<-l>[I<octnum>]
+X<-l> X<$/> X<$\>
+
+enables automatic line-ending processing. It has two separate
+effects. First, it automatically chomps C<$/> (the input record
+separator) when used with B<-n> or B<-p>. Second, it assigns C<$\>
+(the output record separator) to have the value of I<octnum> so
+that any print statements will have that separator added back on.
+If I<octnum> is omitted, sets C<$\> to the current value of
+C<$/>. For instance, to trim lines to 80 columns:
+
+ perl -lpe 'substr($_, 80) = ""'
+
+Note that the assignment C<$\ = $/> is done when the switch is processed,
+so the input record separator can be different than the output record
+separator if the B<-l> switch is followed by a B<-0> switch:
+
+ gnufind / -print0 | perl -ln0e 'print "found $_" if -p'
+
+This sets C<$\> to newline and then sets C<$/> to the null character.
+
+=item B<-m>[B<->]I<module>
+X<-m> X<-M>
+
+=item B<-M>[B<->]I<module>
+
+=item B<-M>[B<->]I<'module ...'>
+
+=item B<-[mM]>[B<->]I<module=arg[,arg]...>
+
+B<-m>I<module> executes C<use> I<module> C<();> before executing your
+program.
+
+B<-M>I<module> executes C<use> I<module> C<;> before executing your
+program. You can use quotes to add extra code after the module name,
+e.g., C<'-Mmodule qw(foo bar)'>.
+
+If the first character after the B<-M> or B<-m> is a dash (C<->)
+then the 'use' is replaced with 'no'.
+
+A little builtin syntactic sugar means you can also say
+B<-mmodule=foo,bar> or B<-Mmodule=foo,bar> as a shortcut for
+C<'-Mmodule qw(foo bar)'>. This avoids the need to use quotes when
+importing symbols. The actual code generated by B<-Mmodule=foo,bar> is
+C<use module split(/,/,q{foo,bar})>. Note that the C<=> form
+removes the distinction between B<-m> and B<-M>.
+
+A consequence of this is that B<-MFoo=number> never does a version check
+(unless C<Foo::import()> itself is set up to do a version check, which
+could happen for example if Foo inherits from Exporter.)
+
+=item B<-n>
+X<-n>
+
+causes Perl to assume the following loop around your program, which
+makes it iterate over filename arguments somewhat like B<sed -n> or
+B<awk>:
+
+ LINE:
+ while (<>) {
+ ... # your program goes here
+ }
+
+Note that the lines are not printed by default. See B<-p> to have
+lines printed. If a file named by an argument cannot be opened for
+some reason, Perl warns you about it and moves on to the next file.
+
+Also note that C<< <> >> passes command line arguments to
+L<perlfunc/open>, which doesn't necessarily interpret them as file names.
+See L<perlop> for possible security implications.
+
+Here is an efficient way to delete all files that haven't been modified for
+at least a week:
+
+ find . -mtime +7 -print | perl -nle unlink
+
+This is faster than using the B<-exec> switch of B<find> because you don't
+have to start a process on every filename found. It does suffer from
+the bug of mishandling newlines in pathnames, which you can fix if
+you follow the example under B<-0>.
+
+C<BEGIN> and C<END> blocks may be used to capture control before or after
+the implicit program loop, just as in B<awk>.
+
+=item B<-p>
+X<-p>
+
+causes Perl to assume the following loop around your program, which
+makes it iterate over filename arguments somewhat like B<sed>:
+
+
+ LINE:
+ while (<>) {
+ ... # your program goes here
+ } continue {
+ print or die "-p destination: $!\n";
+ }
+
+If a file named by an argument cannot be opened for some reason, Perl
+warns you about it, and moves on to the next file. Note that the
+lines are printed automatically. An error occurring during printing is
+treated as fatal. To suppress printing use the B<-n> switch. A B<-p>
+overrides a B<-n> switch.
+
+C<BEGIN> and C<END> blocks may be used to capture control before or after
+the implicit loop, just as in B<awk>.
+
+=item B<-s>
+X<-s>
+
+enables rudimentary switch parsing for switches on the command
+line after the program name but before any filename arguments (or before
+an argument of B<-->). Any switch found there is removed from @ARGV and sets the
+corresponding variable in the Perl program. The following program
+prints "1" if the program is invoked with a B<-xyz> switch, and "abc"
+if it is invoked with B<-xyz=abc>.
+
+ #!/usr/bin/perl -s
+ if ($xyz) { print "$xyz\n" }
+
+Do note that a switch like B<--help> creates the variable ${-help}, which is not compliant
+with C<strict refs>. Also, when using this option on a script with
+warnings enabled you may get a lot of spurious "used only once" warnings.
+
+=item B<-S>
+X<-S>
+
+makes Perl use the PATH environment variable to search for the
+program (unless the name of the program contains directory separators).
+
+On some platforms, this also makes Perl append suffixes to the
+filename while searching for it. For example, on Win32 platforms,
+the ".bat" and ".cmd" suffixes are appended if a lookup for the
+original name fails, and if the name does not already end in one
+of those suffixes. If your Perl was compiled with DEBUGGING turned
+on, using the -Dp switch to Perl shows how the search progresses.
+
+Typically this is used to emulate #! startup on platforms that don't
+support #!. Its also convenient when debugging a script that uses #!,
+and is thus normally found by the shell's $PATH search mechanism.
+
+This example works on many platforms that have a shell compatible with
+Bourne shell:
+
+ #!/usr/bin/perl
+ eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
+ if $running_under_some_shell;
+
+The system ignores the first line and feeds the program to F</bin/sh>,
+which proceeds to try to execute the Perl program as a shell script.
+The shell executes the second line as a normal shell command, and thus
+starts up the Perl interpreter. On some systems $0 doesn't always
+contain the full pathname, so the B<-S> tells Perl to search for the
+program if necessary. After Perl locates the program, it parses the
+lines and ignores them because the variable $running_under_some_shell
+is never true. If the program will be interpreted by csh, you will need
+to replace C<${1+"$@"}> with C<$*>, even though that doesn't understand
+embedded spaces (and such) in the argument list. To start up sh rather
+than csh, some systems may have to replace the #! line with a line
+containing just a colon, which will be politely ignored by Perl. Other
+systems can't control that, and need a totally devious construct that
+will work under any of B<csh>, B<sh>, or Perl, such as the following:
+
+ eval '(exit $?0)' && eval 'exec perl -wS $0 ${1+"$@"}'
+ & eval 'exec /usr/bin/perl -wS $0 $argv:q'
+ if $running_under_some_shell;
+
+If the filename supplied contains directory separators (i.e., is an
+absolute or relative pathname), and if that file is not found,
+platforms that append file extensions will do so and try to look
+for the file with those extensions added, one by one.
+
+On DOS-like platforms, if the program does not contain directory
+separators, it will first be searched for in the current directory
+before being searched for on the PATH. On Unix platforms, the
+program will be searched for strictly on the PATH.
+
+=item B<-t>
+X<-t>
+
+Like B<-T>, but taint checks will issue warnings rather than fatal
+errors. These warnings can be controlled normally with C<no warnings
+qw(taint)>.
+
+B<NOTE: this is not a substitute for -T.> This is meant only to be
+used as a temporary development aid while securing legacy code:
+for real production code and for new secure code written from scratch
+always use the real B<-T>.
+
+=item B<-T>
+X<-T>
+
+forces "taint" checks to be turned on so you can test them. Ordinarily
+these checks are done only when running setuid or setgid. It's a
+good idea to turn them on explicitly for programs that run on behalf
+of someone else whom you might not necessarily trust, such as CGI
+programs or any internet servers you might write in Perl. See
+L<perlsec> for details. For security reasons, this option must be
+seen by Perl quite early; usually this means it must appear early
+on the command line or in the #! line for systems which support
+that construct.
+
+=item B<-u>
+X<-u>
+
+This obsolete switch causes Perl to dump core after compiling your
+program. You can then in theory take this core dump and turn it
+into an executable file by using the B<undump> program (not supplied).
+This speeds startup at the expense of some disk space (which you
+can minimize by stripping the executable). (Still, a "hello world"
+executable comes out to about 200K on my machine.) If you want to
+execute a portion of your program before dumping, use the dump()
+operator instead. Note: availability of B<undump> is platform
+specific and may not be available for a specific port of Perl.
+
+=item B<-U>
+X<-U>
+
+allows Perl to do unsafe operations. Currently the only "unsafe"
+operations are attempting to unlink directories while running as
+superuser, and running setuid programs with fatal taint checks turned
+into warnings. Note that the B<-w> switch (or the C<$^W> variable)
+must be used along with this option to actually I<generate> the
+taint-check warnings.
+
+=item B<-v>
+X<-v>
+
+prints the version and patchlevel of your perl executable.
+
+=item B<-V>
+X<-V>
+
+prints summary of the major perl configuration values and the current
+values of @INC.
+
+=item B<-V:>I<configvar>
+
+Prints to STDOUT the value of the named configuration variable(s),
+with multiples when your configvar argument looks like a regex (has
+non-letters). For example:
+
+ $ perl -V:libc
+ libc='/lib/libc-2.2.4.so';
+ $ perl -V:lib.
+ libs='-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc';
+ libc='/lib/libc-2.2.4.so';
+ $ perl -V:lib.*
+ libpth='/usr/local/lib /lib /usr/lib';
+ libs='-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc';
+ lib_ext='.a';
+ libc='/lib/libc-2.2.4.so';
+ libperl='libperl.a';
+ ....
+
+Additionally, extra colons can be used to control formatting. A
+trailing colon suppresses the linefeed and terminator ';', allowing
+you to embed queries into shell commands. (mnemonic: PATH separator
+':'.)
+
+ $ echo "compression-vars: " `perl -V:z.*: ` " are here !"
+ compression-vars: zcat='' zip='zip' are here !
+
+A leading colon removes the 'name=' part of the response, this allows
+you to map to the name you need. (mnemonic: empty label)
+
+ $ echo "goodvfork="`./perl -Ilib -V::usevfork`
+ goodvfork=false;
+
+Leading and trailing colons can be used together if you need
+positional parameter values without the names. Note that in the case
+below, the PERL_API params are returned in alphabetical order.
+
+ $ echo building_on `perl -V::osname: -V::PERL_API_.*:` now
+ building_on 'linux' '5' '1' '9' now
+
+=item B<-w>
+X<-w>
+
+prints warnings about dubious constructs, such as variable names
+that are mentioned only once and scalar variables that are used
+before being set, redefined subroutines, references to undefined
+filehandles or filehandles opened read-only that you are attempting
+to write on, values used as a number that don't look like numbers,
+using an array as though it were a scalar, if your subroutines
+recurse more than 100 deep, and innumerable other things.
+
+This switch really just enables the internal C<$^W> variable. You
+can disable or promote into fatal errors specific warnings using
+C<__WARN__> hooks, as described in L<perlvar> and L<perlfunc/warn>.
+See also L<perldiag> and L<perltrap>. A new, fine-grained warning
+facility is also available if you want to manipulate entire classes
+of warnings; see L<warnings> or L<perllexwarn>.
+
+=item B<-W>
+X<-W>
+
+Enables all warnings regardless of C<no warnings> or C<$^W>.
+See L<perllexwarn>.
+
+=item B<-X>
+X<-X>
+
+Disables all warnings regardless of C<use warnings> or C<$^W>.
+See L<perllexwarn>.
+
+=item B<-x>
+X<-x>
+
+=item B<-x>I<directory>
+
+tells Perl that the program is embedded in a larger chunk of unrelated
+ASCII text, such as in a mail message. Leading garbage will be
+discarded until the first line that starts with #! and contains the
+string "perl". Any meaningful switches on that line will be applied.
+
+All references to line numbers by the program (warnings, errors, ...)
+will treat the #! line as the first line.
+Thus a warning on the 2nd line of the program (which is on the 100th
+line in the file) will be reported as line 2, and not as line 100.
+This can be overridden by using the #line directive.
+(See L<perlsyn/"Plain-Old-Comments-(Not!)">)
+
+If a directory name is specified, Perl will switch to that directory
+before running the program. The B<-x> switch controls only the
+disposal of leading garbage. The program must be terminated with
+C<__END__> if there is trailing garbage to be ignored (the program
+can process any or all of the trailing garbage via the DATA filehandle
+if desired).
+
+The directory, if specified, must appear immediately following the B<-x>
+with no intervening whitespace.
+
+=back
+
+=head1 ENVIRONMENT
+X<perl, environment variables>
+
+=over 12
+
+=item HOME
+X<HOME>
+
+Used if chdir has no argument.
+
+=item LOGDIR
+X<LOGDIR>
+
+Used if chdir has no argument and HOME is not set.
+
+=item PATH
+X<PATH>
+
+Used in executing subprocesses, and in finding the program if B<-S> is
+used.
+
+=item PERL5LIB
+X<PERL5LIB>
+
+A list of directories in which to look for Perl library
+files before looking in the standard library and the current
+directory. Any architecture-specific directories under the specified
+locations are automatically included if they exist (this lookup
+being done at interpreter startup time.)
+
+If PERL5LIB is not defined, PERLLIB is used. Directories are separated
+(like in PATH) by a colon on Unixish platforms and by a semicolon on
+Windows (the proper path separator being given by the command C<perl
+-V:path_sep>).
+
+When running taint checks (either because the program was running setuid
+or setgid, or the B<-T> or B<-t> switch was specified), neither variable
+is used. The program should instead say:
+
+ use lib "/my/directory";
+
+=item PERL5OPT
+X<PERL5OPT>
+
+Command-line options (switches). Switches in this variable are taken
+as if they were on every Perl command line. Only the B<-[CDIMUdmtwW]>
+switches are allowed. When running taint checks (because the program
+was running setuid or setgid, or the B<-T> switch was used), this
+variable is ignored. If PERL5OPT begins with B<-T>, tainting will be
+enabled, and any subsequent options ignored.
+
+=item PERLIO
+X<PERLIO>
+
+A space (or colon) separated list of PerlIO layers. If perl is built
+to use PerlIO system for IO (the default) these layers effect perl's IO.
+
+It is conventional to start layer names with a colon e.g. C<:perlio> to
+emphasise their similarity to variable "attributes". But the code that parses
+layer specification strings (which is also used to decode the PERLIO
+environment variable) treats the colon as a separator.
+
+An unset or empty PERLIO is equivalent to the default set of layers for
+your platform, for example C<:unix:perlio> on Unix-like systems
+and C<:unix:crlf> on Windows and other DOS-like systems.
+
+The list becomes the default for I<all> perl's IO. Consequently only built-in
+layers can appear in this list, as external layers (such as :encoding()) need
+IO in order to load them!. See L<"open pragma"|open> for how to add external
+encodings as defaults.
+
+The layers that it makes sense to include in the PERLIO environment
+variable are briefly summarised below. For more details see L<PerlIO>.
+
+=over 8
+
+=item :bytes
+X<:bytes>
+
+A pseudolayer that turns I<off> the C<:utf8> flag for the layer below.
+Unlikely to be useful on its own in the global PERLIO environment variable.
+You perhaps were thinking of C<:crlf:bytes> or C<:perlio:bytes>.
+
+=item :crlf
+X<:crlf>
+
+A layer which does CRLF to "\n" translation distinguishing "text" and
+"binary" files in the manner of MS-DOS and similar operating systems.
+(It currently does I<not> mimic MS-DOS as far as treating of Control-Z
+as being an end-of-file marker.)
+
+=item :mmap
+X<:mmap>
+
+A layer which implements "reading" of files by using C<mmap()> to
+make (whole) file appear in the process's address space, and then
+using that as PerlIO's "buffer".
+
+=item :perlio
+X<:perlio>
+
+This is a re-implementation of "stdio-like" buffering written as a
+PerlIO "layer". As such it will call whatever layer is below it for
+its operations (typically C<:unix>).
+
+=item :pop
+X<:pop>
+
+An experimental pseudolayer that removes the topmost layer.
+Use with the same care as is reserved for nitroglycerin.
+
+=item :raw
+X<:raw>
+
+A pseudolayer that manipulates other layers. Applying the C<:raw>
+layer is equivalent to calling C<binmode($fh)>. It makes the stream
+pass each byte as-is without any translation. In particular CRLF
+translation, and/or :utf8 intuited from locale are disabled.
+
+Unlike in the earlier versions of Perl C<:raw> is I<not>
+just the inverse of C<:crlf> - other layers which would affect the
+binary nature of the stream are also removed or disabled.
+
+=item :stdio
+X<:stdio>
+
+This layer provides PerlIO interface by wrapping system's ANSI C "stdio"
+library calls. The layer provides both buffering and IO.
+Note that C<:stdio> layer does I<not> do CRLF translation even if that
+is platforms normal behaviour. You will need a C<:crlf> layer above it
+to do that.
+
+=item :unix
+X<:unix>
+
+Low level layer which calls C<read>, C<write> and C<lseek> etc.
+
+=item :utf8
+X<:utf8>
+
+A pseudolayer that turns on a flag on the layer below to tell perl
+that output should be in utf8 and that input should be regarded as
+already in valid utf8 form. It does not check for validity and as such
+should be handled with caution for input. Generally C<:encoding(utf8)> is
+the best option when reading UTF-8 encoded data.
+
+=item :win32
+X<:win32>
+
+On Win32 platforms this I<experimental> layer uses native "handle" IO
+rather than unix-like numeric file descriptor layer. Known to be
+buggy in this release.
+
+=back
+
+On all platforms the default set of layers should give acceptable results.
+
+For Unix platforms that will equivalent of "unix perlio" or "stdio".
+Configure is setup to prefer "stdio" implementation if system's library
+provides for fast access to the buffer, otherwise it uses the "unix perlio"
+implementation.
+
+On Win32 the default in this release is "unix crlf". Win32's "stdio"
+has a number of bugs/mis-features for perl IO which are somewhat
+C compiler vendor/version dependent. Using our own C<crlf> layer as
+the buffer avoids those issues and makes things more uniform.
+The C<crlf> layer provides CRLF to/from "\n" conversion as well as
+buffering.
+
+This release uses C<unix> as the bottom layer on Win32 and so still uses C
+compiler's numeric file descriptor routines. There is an experimental native
+C<win32> layer which is expected to be enhanced and should eventually be
+the default under Win32.
+
+The PERLIO environment variable is completely ignored when perl
+is run in taint mode.
+
+=item PERLIO_DEBUG
+X<PERLIO_DEBUG>
+
+If set to the name of a file or device then certain operations of PerlIO
+sub-system will be logged to that file (opened as append). Typical uses
+are Unix:
+
+ PERLIO_DEBUG=/dev/tty perl script ...
+
+and Win32 approximate equivalent:
+
+ set PERLIO_DEBUG=CON
+ perl script ...
+
+This functionality is disabled for setuid scripts and for scripts run
+with B<-T>.
+
+=item PERLLIB
+X<PERLLIB>
+
+A list of directories in which to look for Perl library
+files before looking in the standard library and the current directory.
+If PERL5LIB is defined, PERLLIB is not used.
+
+The PERLLIB environment variable is completely ignored when perl
+is run in taint mode.
+
+=item PERL5DB
+X<PERL5DB>
+
+The command used to load the debugger code. The default is:
+
+ BEGIN { require 'perl5db.pl' }
+
+The PERL5DB environment variable only used when perl is started with
+a bare B<-d> switch.
+
+=item PERL5DB_THREADED
+X<PERL5DB_THREADED>
+
+If set to a true value, indicates to the debugger that the code being
+debugged uses threads.
+
+=item PERL5SHELL (specific to the Win32 port)
+X<PERL5SHELL>
+
+May be set to an alternative shell that perl must use internally for
+executing "backtick" commands or system(). Default is C<cmd.exe /x/d/c>
+on WindowsNT and C<command.com /c> on Windows95. The value is considered
+to be space-separated. Precede any character that needs to be protected
+(like a space or backslash) with a backslash.
+
+Note that Perl doesn't use COMSPEC for this purpose because
+COMSPEC has a high degree of variability among users, leading to
+portability concerns. Besides, perl can use a shell that may not be
+fit for interactive use, and setting COMSPEC to such a shell may
+interfere with the proper functioning of other programs (which usually
+look in COMSPEC to find a shell fit for interactive use).
+
+Before Perl 5.10.0 and 5.8.8, PERL5SHELL was not taint checked
+when running external commands. It is recommended that
+you explicitly set (or delete) C<$ENV{PERL5SHELL}> when running
+in taint mode under Windows.
+
+=item PERL_ALLOW_NON_IFS_LSP (specific to the Win32 port)
+X<PERL_ALLOW_NON_IFS_LSP>
+
+Set to 1 to allow the use of non-IFS compatible LSP's.
+Perl normally searches for an IFS-compatible LSP because this is required
+for its emulation of Windows sockets as real filehandles. However, this may
+cause problems if you have a firewall such as McAfee Guardian which requires
+all applications to use its LSP which is not IFS-compatible, because clearly
+Perl will normally avoid using such an LSP.
+Setting this environment variable to 1 means that Perl will simply use the
+first suitable LSP enumerated in the catalog, which keeps McAfee Guardian
+happy (and in that particular case Perl still works too because McAfee
+Guardian's LSP actually plays some other games which allow applications
+requiring IFS compatibility to work).
+
+=item PERL_DEBUG_MSTATS
+X<PERL_DEBUG_MSTATS>
+
+Relevant only if perl is compiled with the malloc included with the perl
+distribution (that is, if C<perl -V:d_mymalloc> is 'define').
+If set, this causes memory statistics to be dumped after execution. If set
+to an integer greater than one, also causes memory statistics to be dumped
+after compilation.
+
+=item PERL_DESTRUCT_LEVEL
+X<PERL_DESTRUCT_LEVEL>
+
+Relevant only if your perl executable was built with B<-DDEBUGGING>,
+this controls the behavior of global destruction of objects and other
+references. See L<perlhack/PERL_DESTRUCT_LEVEL> for more information.
+
+=item PERL_DL_NONLAZY
+X<PERL_DL_NONLAZY>
+
+Set to one to have perl resolve B<all> undefined symbols when it loads
+a dynamic library. The default behaviour is to resolve symbols when
+they are used. Setting this variable is useful during testing of
+extensions as it ensures that you get an error on misspelled function
+names even if the test suite doesn't call it.
+
+=item PERL_ENCODING
+X<PERL_ENCODING>
+
+If using the C<encoding> pragma without an explicit encoding name, the
+PERL_ENCODING environment variable is consulted for an encoding name.
+
+=item PERL_HASH_SEED
+X<PERL_HASH_SEED>
+
+(Since Perl 5.8.1.) Used to randomise perl's internal hash function.
+To emulate the pre-5.8.1 behaviour, set to an integer (zero means
+exactly the same order as 5.8.0). "Pre-5.8.1" means, among other
+things, that hash keys will always have the same ordering between
+different runs of perl.
+
+Most hashes return elements in the same order as Perl 5.8.0 by default.
+On a hash by hash basis, if pathological data is detected during a hash
+key insertion, then that hash will switch to an alternative random hash
+seed.
+
+The default behaviour is to randomise unless the PERL_HASH_SEED is set.
+If perl has been compiled with C<-DUSE_HASH_SEED_EXPLICIT>, the default
+behaviour is B<not> to randomise unless the PERL_HASH_SEED is set.
+
+If PERL_HASH_SEED is unset or set to a non-numeric string, perl uses
+the pseudorandom seed supplied by the operating system and libraries.
+
+B<Please note that the hash seed is sensitive information>. Hashes are
+randomized to protect against local and remote attacks against Perl
+code. By manually setting a seed this protection may be partially or
+completely lost.
+
+See L<perlsec/"Algorithmic Complexity Attacks"> and
+L</PERL_HASH_SEED_DEBUG> for more information.
+
+=item PERL_HASH_SEED_DEBUG
+X<PERL_HASH_SEED_DEBUG>
+
+(Since Perl 5.8.1.) Set to one to display (to STDERR) the value of
+the hash seed at the beginning of execution. This, combined with
+L</PERL_HASH_SEED> is intended to aid in debugging nondeterministic
+behavior caused by hash randomization.
+
+B<Note that the hash seed is sensitive information>: by knowing it one
+can craft a denial-of-service attack against Perl code, even remotely,
+see L<perlsec/"Algorithmic Complexity Attacks"> for more information.
+B<Do not disclose the hash seed> to people who don't need to know it.
+See also hash_seed() of L<Hash::Util>.
+
+=item PERL_MEM_LOG
+X<PERL_MEM_LOG>
+
+If your perl was configured with C<-Accflags=-DPERL_MEM_LOG>, setting
+the environment variable C<PERL_MEM_LOG> enables logging debug
+messages. The value has the form C<< <number>[m][s][t] >>, where
+C<number> is the filedescriptor number you want to write to (2 is
+default), and the combination of letters specifies that you want
+information about (m)emory and/or (s)v, optionally with
+(t)imestamps. For example C<PERL_MEM_LOG=1mst> will log all
+information to stdout. You can write to other opened filedescriptors
+too, in a variety of ways;
+
+ bash$ 3>foo3 PERL_MEM_LOG=3m perl ...
+
+=item PERL_ROOT (specific to the VMS port)
+X<PERL_ROOT>
+
+A translation concealed rooted logical name that contains perl and the
+logical device for the @INC path on VMS only. Other logical names that
+affect perl on VMS include PERLSHR, PERL_ENV_TABLES, and
+SYS$TIMEZONE_DIFFERENTIAL but are optional and discussed further in
+L<perlvms> and in F<README.vms> in the Perl source distribution.
+
+=item PERL_SIGNALS
+X<PERL_SIGNALS>
+
+In Perls 5.8.1 and later. If set to C<unsafe> the pre-Perl-5.8.0
+signals behaviour (immediate but unsafe) is restored. If set to
+C<safe> the safe (or deferred) signals are used.
+See L<perlipc/"Deferred Signals (Safe Signals)">.
+
+=item PERL_UNICODE
+X<PERL_UNICODE>
+
+Equivalent to the B<-C> command-line switch. Note that this is not
+a boolean variable. Setting this to C<"1"> is not the right way to
+"enable Unicode" (whatever that would mean). You can use C<"0"> to
+"disable Unicode", though (or alternatively unset PERL_UNICODE in
+your shell before starting Perl). See the description of the C<-C>
+switch for more information.
+
+=item SYS$LOGIN (specific to the VMS port)
+X<SYS$LOGIN>
+
+Used if chdir has no argument and HOME and LOGDIR are not set.
+
+=back
+
+Perl also has environment variables that control how Perl handles data
+specific to particular natural languages. See L<perllocale>.
+
+Apart from these, Perl uses no other environment variables, except
+to make them available to the program being executed, and to child
+processes. However, programs running setuid would do well to execute
+the following lines before doing anything else, just to keep people
+honest:
+
+ $ENV{PATH} = '/bin:/usr/bin'; # or whatever you need
+ $ENV{SHELL} = '/bin/sh' if exists $ENV{SHELL};
+ delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};
diff --git a/Master/tlpkg/tlperl/lib/pods/perlsec.pod b/Master/tlpkg/tlperl/lib/pods/perlsec.pod
new file mode 100644
index 00000000000..1c49453d535
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlsec.pod
@@ -0,0 +1,520 @@
+=head1 NAME
+
+perlsec - Perl security
+
+=head1 DESCRIPTION
+
+Perl is designed to make it easy to program securely even when running
+with extra privileges, like setuid or setgid programs. Unlike most
+command line shells, which are based on multiple substitution passes on
+each line of the script, Perl uses a more conventional evaluation scheme
+with fewer hidden snags. Additionally, because the language has more
+builtin functionality, it can rely less upon external (and possibly
+untrustworthy) programs to accomplish its purposes.
+
+=head1 SECURITY VULNERABILITY CONTACT INFORMATION
+
+If you believe you have found a security vulnerability in Perl, please email
+perl5-security-report@perl.org with details. This points to a closed
+subscription, unarchived mailing list. Please only use this address for
+security issues in the Perl core, not for modules independently distributed on
+CPAN.
+
+=head1 SECURITY MECHANISMS AND CONCERNS
+
+=head2 Taint mode
+
+Perl automatically enables a set of special security checks, called I<taint
+mode>, when it detects its program running with differing real and effective
+user or group IDs. The setuid bit in Unix permissions is mode 04000, the
+setgid bit mode 02000; either or both may be set. You can also enable taint
+mode explicitly by using the B<-T> command line flag. This flag is
+I<strongly> suggested for server programs and any program run on behalf of
+someone else, such as a CGI script. Once taint mode is on, it's on for
+the remainder of your script.
+
+While in this mode, Perl takes special precautions called I<taint
+checks> to prevent both obvious and subtle traps. Some of these checks
+are reasonably simple, such as verifying that path directories aren't
+writable by others; careful programmers have always used checks like
+these. Other checks, however, are best supported by the language itself,
+and it is these checks especially that contribute to making a set-id Perl
+program more secure than the corresponding C program.
+
+You may not use data derived from outside your program to affect
+something else outside your program--at least, not by accident. All
+command line arguments, environment variables, locale information (see
+L<perllocale>), results of certain system calls (C<readdir()>,
+C<readlink()>, the variable of C<shmread()>, the messages returned by
+C<msgrcv()>, the password, gcos and shell fields returned by the
+C<getpwxxx()> calls), and all file input are marked as "tainted".
+Tainted data may not be used directly or indirectly in any command
+that invokes a sub-shell, nor in any command that modifies files,
+directories, or processes, B<with the following exceptions>:
+
+=over 4
+
+=item *
+
+Arguments to C<print> and C<syswrite> are B<not> checked for taintedness.
+
+=item *
+
+Symbolic methods
+
+ $obj->$method(@args);
+
+and symbolic sub references
+
+ &{$foo}(@args);
+ $foo->(@args);
+
+are not checked for taintedness. This requires extra carefulness
+unless you want external data to affect your control flow. Unless
+you carefully limit what these symbolic values are, people are able
+to call functions B<outside> your Perl code, such as POSIX::system,
+in which case they are able to run arbitrary external code.
+
+=item *
+
+Hash keys are B<never> tainted.
+
+=back
+
+For efficiency reasons, Perl takes a conservative view of
+whether data is tainted. If an expression contains tainted data,
+any subexpression may be considered tainted, even if the value
+of the subexpression is not itself affected by the tainted data.
+
+Because taintedness is associated with each scalar value, some
+elements of an array or hash can be tainted and others not.
+The keys of a hash are B<never> tainted.
+
+For example:
+
+ $arg = shift; # $arg is tainted
+ $hid = $arg, 'bar'; # $hid is also tainted
+ $line = <>; # Tainted
+ $line = <STDIN>; # Also tainted
+ open FOO, "/home/me/bar" or die $!;
+ $line = <FOO>; # Still tainted
+ $path = $ENV{'PATH'}; # Tainted, but see below
+ $data = 'abc'; # Not tainted
+
+ system "echo $arg"; # Insecure
+ system "/bin/echo", $arg; # Considered insecure
+ # (Perl doesn't know about /bin/echo)
+ system "echo $hid"; # Insecure
+ system "echo $data"; # Insecure until PATH set
+
+ $path = $ENV{'PATH'}; # $path now tainted
+
+ $ENV{'PATH'} = '/bin:/usr/bin';
+ delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
+
+ $path = $ENV{'PATH'}; # $path now NOT tainted
+ system "echo $data"; # Is secure now!
+
+ open(FOO, "< $arg"); # OK - read-only file
+ open(FOO, "> $arg"); # Not OK - trying to write
+
+ open(FOO,"echo $arg|"); # Not OK
+ open(FOO,"-|")
+ or exec 'echo', $arg; # Also not OK
+
+ $shout = `echo $arg`; # Insecure, $shout now tainted
+
+ unlink $data, $arg; # Insecure
+ umask $arg; # Insecure
+
+ exec "echo $arg"; # Insecure
+ exec "echo", $arg; # Insecure
+ exec "sh", '-c', $arg; # Very insecure!
+
+ @files = <*.c>; # insecure (uses readdir() or similar)
+ @files = glob('*.c'); # insecure (uses readdir() or similar)
+
+ # In Perl releases older than 5.6.0 the <*.c> and glob('*.c') would
+ # have used an external program to do the filename expansion; but in
+ # either case the result is tainted since the list of filenames comes
+ # from outside of the program.
+
+ $bad = ($arg, 23); # $bad will be tainted
+ $arg, `true`; # Insecure (although it isn't really)
+
+If you try to do something insecure, you will get a fatal error saying
+something like "Insecure dependency" or "Insecure $ENV{PATH}".
+
+The exception to the principle of "one tainted value taints the whole
+expression" is with the ternary conditional operator C<?:>. Since code
+with a ternary conditional
+
+ $result = $tainted_value ? "Untainted" : "Also untainted";
+
+is effectively
+
+ if ( $tainted_value ) {
+ $result = "Untainted";
+ } else {
+ $result = "Also untainted";
+ }
+
+it doesn't make sense for C<$result> to be tainted.
+
+=head2 Laundering and Detecting Tainted Data
+
+To test whether a variable contains tainted data, and whose use would
+thus trigger an "Insecure dependency" message, you can use the
+C<tainted()> function of the Scalar::Util module, available in your
+nearby CPAN mirror, and included in Perl starting from the release 5.8.0.
+Or you may be able to use the following C<is_tainted()> function.
+
+ sub is_tainted {
+ return ! eval { eval("#" . substr(join("", @_), 0, 0)); 1 };
+ }
+
+This function makes use of the fact that the presence of tainted data
+anywhere within an expression renders the entire expression tainted. It
+would be inefficient for every operator to test every argument for
+taintedness. Instead, the slightly more efficient and conservative
+approach is used that if any tainted value has been accessed within the
+same expression, the whole expression is considered tainted.
+
+But testing for taintedness gets you only so far. Sometimes you have just
+to clear your data's taintedness. Values may be untainted by using them
+as keys in a hash; otherwise the only way to bypass the tainting
+mechanism is by referencing subpatterns from a regular expression match.
+Perl presumes that if you reference a substring using $1, $2, etc., that
+you knew what you were doing when you wrote the pattern. That means using
+a bit of thought--don't just blindly untaint anything, or you defeat the
+entire mechanism. It's better to verify that the variable has only good
+characters (for certain values of "good") rather than checking whether it
+has any bad characters. That's because it's far too easy to miss bad
+characters that you never thought of.
+
+Here's a test to make sure that the data contains nothing but "word"
+characters (alphabetics, numerics, and underscores), a hyphen, an at sign,
+or a dot.
+
+ if ($data =~ /^([-\@\w.]+)$/) {
+ $data = $1; # $data now untainted
+ } else {
+ die "Bad data in '$data'"; # log this somewhere
+ }
+
+This is fairly secure because C</\w+/> doesn't normally match shell
+metacharacters, nor are dot, dash, or at going to mean something special
+to the shell. Use of C</.+/> would have been insecure in theory because
+it lets everything through, but Perl doesn't check for that. The lesson
+is that when untainting, you must be exceedingly careful with your patterns.
+Laundering data using regular expression is the I<only> mechanism for
+untainting dirty data, unless you use the strategy detailed below to fork
+a child of lesser privilege.
+
+The example does not untaint C<$data> if C<use locale> is in effect,
+because the characters matched by C<\w> are determined by the locale.
+Perl considers that locale definitions are untrustworthy because they
+contain data from outside the program. If you are writing a
+locale-aware program, and want to launder data with a regular expression
+containing C<\w>, put C<no locale> ahead of the expression in the same
+block. See L<perllocale/SECURITY> for further discussion and examples.
+
+=head2 Switches On the "#!" Line
+
+When you make a script executable, in order to make it usable as a
+command, the system will pass switches to perl from the script's #!
+line. Perl checks that any command line switches given to a setuid
+(or setgid) script actually match the ones set on the #! line. Some
+Unix and Unix-like environments impose a one-switch limit on the #!
+line, so you may need to use something like C<-wU> instead of C<-w -U>
+under such systems. (This issue should arise only in Unix or
+Unix-like environments that support #! and setuid or setgid scripts.)
+
+=head2 Taint mode and @INC
+
+When the taint mode (C<-T>) is in effect, the "." directory is removed
+from C<@INC>, and the environment variables C<PERL5LIB> and C<PERLLIB>
+are ignored by Perl. You can still adjust C<@INC> from outside the
+program by using the C<-I> command line option as explained in
+L<perlrun>. The two environment variables are ignored because
+they are obscured, and a user running a program could be unaware that
+they are set, whereas the C<-I> option is clearly visible and
+therefore permitted.
+
+Another way to modify C<@INC> without modifying the program, is to use
+the C<lib> pragma, e.g.:
+
+ perl -Mlib=/foo program
+
+The benefit of using C<-Mlib=/foo> over C<-I/foo>, is that the former
+will automagically remove any duplicated directories, while the later
+will not.
+
+Note that if a tainted string is added to C<@INC>, the following
+problem will be reported:
+
+ Insecure dependency in require while running with -T switch
+
+=head2 Cleaning Up Your Path
+
+For "Insecure C<$ENV{PATH}>" messages, you need to set C<$ENV{'PATH'}> to
+a known value, and each directory in the path must be absolute and
+non-writable by others than its owner and group. You may be surprised to
+get this message even if the pathname to your executable is fully
+qualified. This is I<not> generated because you didn't supply a full path
+to the program; instead, it's generated because you never set your PATH
+environment variable, or you didn't set it to something that was safe.
+Because Perl can't guarantee that the executable in question isn't itself
+going to turn around and execute some other program that is dependent on
+your PATH, it makes sure you set the PATH.
+
+The PATH isn't the only environment variable which can cause problems.
+Because some shells may use the variables IFS, CDPATH, ENV, and
+BASH_ENV, Perl checks that those are either empty or untainted when
+starting subprocesses. You may wish to add something like this to your
+setid and taint-checking scripts.
+
+ delete @ENV{qw(IFS CDPATH ENV BASH_ENV)}; # Make %ENV safer
+
+It's also possible to get into trouble with other operations that don't
+care whether they use tainted values. Make judicious use of the file
+tests in dealing with any user-supplied filenames. When possible, do
+opens and such B<after> properly dropping any special user (or group!)
+privileges. Perl doesn't prevent you from opening tainted filenames for reading,
+so be careful what you print out. The tainting mechanism is intended to
+prevent stupid mistakes, not to remove the need for thought.
+
+Perl does not call the shell to expand wild cards when you pass C<system>
+and C<exec> explicit parameter lists instead of strings with possible shell
+wildcards in them. Unfortunately, the C<open>, C<glob>, and
+backtick functions provide no such alternate calling convention, so more
+subterfuge will be required.
+
+Perl provides a reasonably safe way to open a file or pipe from a setuid
+or setgid program: just create a child process with reduced privilege who
+does the dirty work for you. First, fork a child using the special
+C<open> syntax that connects the parent and child by a pipe. Now the
+child resets its ID set and any other per-process attributes, like
+environment variables, umasks, current working directories, back to the
+originals or known safe values. Then the child process, which no longer
+has any special permissions, does the C<open> or other system call.
+Finally, the child passes the data it managed to access back to the
+parent. Because the file or pipe was opened in the child while running
+under less privilege than the parent, it's not apt to be tricked into
+doing something it shouldn't.
+
+Here's a way to do backticks reasonably safely. Notice how the C<exec> is
+not called with a string that the shell could expand. This is by far the
+best way to call something that might be subjected to shell escapes: just
+never call the shell at all.
+
+ use English '-no_match_vars';
+ die "Can't fork: $!" unless defined($pid = open(KID, "-|"));
+ if ($pid) { # parent
+ while (<KID>) {
+ # do something
+ }
+ close KID;
+ } else {
+ my @temp = ($EUID, $EGID);
+ my $orig_uid = $UID;
+ my $orig_gid = $GID;
+ $EUID = $UID;
+ $EGID = $GID;
+ # Drop privileges
+ $UID = $orig_uid;
+ $GID = $orig_gid;
+ # Make sure privs are really gone
+ ($EUID, $EGID) = @temp;
+ die "Can't drop privileges"
+ unless $UID == $EUID && $GID eq $EGID;
+ $ENV{PATH} = "/bin:/usr/bin"; # Minimal PATH.
+ # Consider sanitizing the environment even more.
+ exec 'myprog', 'arg1', 'arg2'
+ or die "can't exec myprog: $!";
+ }
+
+A similar strategy would work for wildcard expansion via C<glob>, although
+you can use C<readdir> instead.
+
+Taint checking is most useful when although you trust yourself not to have
+written a program to give away the farm, you don't necessarily trust those
+who end up using it not to try to trick it into doing something bad. This
+is the kind of security checking that's useful for set-id programs and
+programs launched on someone else's behalf, like CGI programs.
+
+This is quite different, however, from not even trusting the writer of the
+code not to try to do something evil. That's the kind of trust needed
+when someone hands you a program you've never seen before and says, "Here,
+run this." For that kind of safety, you might want to check out the Safe
+module, included standard in the Perl distribution. This module allows the
+programmer to set up special compartments in which all system operations
+are trapped and namespace access is carefully controlled. Safe should
+not be considered bullet-proof, though: it will not prevent the foreign
+code to set up infinite loops, allocate gigabytes of memory, or even
+abusing perl bugs to make the host interpreter crash or behave in
+unpredictable ways. In any case it's better avoided completely if you're
+really concerned about security.
+
+=head2 Security Bugs
+
+Beyond the obvious problems that stem from giving special privileges to
+systems as flexible as scripts, on many versions of Unix, set-id scripts
+are inherently insecure right from the start. The problem is a race
+condition in the kernel. Between the time the kernel opens the file to
+see which interpreter to run and when the (now-set-id) interpreter turns
+around and reopens the file to interpret it, the file in question may have
+changed, especially if you have symbolic links on your system.
+
+Fortunately, sometimes this kernel "feature" can be disabled.
+Unfortunately, there are two ways to disable it. The system can simply
+outlaw scripts with any set-id bit set, which doesn't help much.
+Alternately, it can simply ignore the set-id bits on scripts.
+
+However, if the kernel set-id script feature isn't disabled, Perl will
+complain loudly that your set-id script is insecure. You'll need to
+either disable the kernel set-id script feature, or put a C wrapper around
+the script. A C wrapper is just a compiled program that does nothing
+except call your Perl program. Compiled programs are not subject to the
+kernel bug that plagues set-id scripts. Here's a simple wrapper, written
+in C:
+
+ #define REAL_PATH "/path/to/script"
+ main(ac, av)
+ char **av;
+ {
+ execv(REAL_PATH, av);
+ }
+
+Compile this wrapper into a binary executable and then make I<it> rather
+than your script setuid or setgid.
+
+In recent years, vendors have begun to supply systems free of this
+inherent security bug. On such systems, when the kernel passes the name
+of the set-id script to open to the interpreter, rather than using a
+pathname subject to meddling, it instead passes I</dev/fd/3>. This is a
+special file already opened on the script, so that there can be no race
+condition for evil scripts to exploit. On these systems, Perl should be
+compiled with C<-DSETUID_SCRIPTS_ARE_SECURE_NOW>. The F<Configure>
+program that builds Perl tries to figure this out for itself, so you
+should never have to specify this yourself. Most modern releases of
+SysVr4 and BSD 4.4 use this approach to avoid the kernel race condition.
+
+=head2 Protecting Your Programs
+
+There are a number of ways to hide the source to your Perl programs,
+with varying levels of "security".
+
+First of all, however, you I<can't> take away read permission, because
+the source code has to be readable in order to be compiled and
+interpreted. (That doesn't mean that a CGI script's source is
+readable by people on the web, though.) So you have to leave the
+permissions at the socially friendly 0755 level. This lets
+people on your local system only see your source.
+
+Some people mistakenly regard this as a security problem. If your program does
+insecure things, and relies on people not knowing how to exploit those
+insecurities, it is not secure. It is often possible for someone to
+determine the insecure things and exploit them without viewing the
+source. Security through obscurity, the name for hiding your bugs
+instead of fixing them, is little security indeed.
+
+You can try using encryption via source filters (Filter::* from CPAN,
+or Filter::Util::Call and Filter::Simple since Perl 5.8).
+But crackers might be able to decrypt it. You can try using the byte
+code compiler and interpreter described below, but crackers might be
+able to de-compile it. You can try using the native-code compiler
+described below, but crackers might be able to disassemble it. These
+pose varying degrees of difficulty to people wanting to get at your
+code, but none can definitively conceal it (this is true of every
+language, not just Perl).
+
+If you're concerned about people profiting from your code, then the
+bottom line is that nothing but a restrictive license will give you
+legal security. License your software and pepper it with threatening
+statements like "This is unpublished proprietary software of XYZ Corp.
+Your access to it does not give you permission to use it blah blah
+blah." You should see a lawyer to be sure your license's wording will
+stand up in court.
+
+=head2 Unicode
+
+Unicode is a new and complex technology and one may easily overlook
+certain security pitfalls. See L<perluniintro> for an overview and
+L<perlunicode> for details, and L<perlunicode/"Security Implications
+of Unicode"> for security implications in particular.
+
+=head2 Algorithmic Complexity Attacks
+
+Certain internal algorithms used in the implementation of Perl can
+be attacked by choosing the input carefully to consume large amounts
+of either time or space or both. This can lead into the so-called
+I<Denial of Service> (DoS) attacks.
+
+=over 4
+
+=item *
+
+Hash Function - the algorithm used to "order" hash elements has been
+changed several times during the development of Perl, mainly to be
+reasonably fast. In Perl 5.8.1 also the security aspect was taken
+into account.
+
+In Perls before 5.8.1 one could rather easily generate data that as
+hash keys would cause Perl to consume large amounts of time because
+internal structure of hashes would badly degenerate. In Perl 5.8.1
+the hash function is randomly perturbed by a pseudorandom seed which
+makes generating such naughty hash keys harder.
+See L<perlrun/PERL_HASH_SEED> for more information.
+
+In Perl 5.8.1 the random perturbation was done by default, but as of
+5.8.2 it is only used on individual hashes if the internals detect the
+insertion of pathological data. If one wants for some reason emulate the
+old behaviour (and expose oneself to DoS attacks) one can set the
+environment variable PERL_HASH_SEED to zero to disable the protection
+(or any other integer to force a known perturbation, rather than random).
+One possible reason for wanting to emulate the old behaviour is that in the
+new behaviour consecutive runs of Perl will order hash keys differently,
+which may confuse some applications (like Data::Dumper: the outputs of two
+different runs are no longer identical).
+
+B<Perl has never guaranteed any ordering of the hash keys>, and the
+ordering has already changed several times during the lifetime of
+Perl 5. Also, the ordering of hash keys has always been, and
+continues to be, affected by the insertion order.
+
+Also note that while the order of the hash elements might be
+randomised, this "pseudoordering" should B<not> be used for
+applications like shuffling a list randomly (use List::Util::shuffle()
+for that, see L<List::Util>, a standard core module since Perl 5.8.0;
+or the CPAN module Algorithm::Numerical::Shuffle), or for generating
+permutations (use e.g. the CPAN modules Algorithm::Permute or
+Algorithm::FastPermute), or for any cryptographic applications.
+
+=item *
+
+Regular expressions - Perl's regular expression engine is so called NFA
+(Non-deterministic Finite Automaton), which among other things means that
+it can rather easily consume large amounts of both time and space if the
+regular expression may match in several ways. Careful crafting of the
+regular expressions can help but quite often there really isn't much
+one can do (the book "Mastering Regular Expressions" is required
+reading, see L<perlfaq2>). Running out of space manifests itself by
+Perl running out of memory.
+
+=item *
+
+Sorting - the quicksort algorithm used in Perls before 5.8.0 to
+implement the sort() function is very easy to trick into misbehaving
+so that it consumes a lot of time. Starting from Perl 5.8.0 a different
+sorting algorithm, mergesort, is used by default. Mergesort cannot
+misbehave on any input.
+
+=back
+
+See L<http://www.cs.rice.edu/~scrosby/hash/> for more information,
+and any computer science textbook on algorithmic complexity.
+
+=head1 SEE ALSO
+
+L<perlrun> for its description of cleaning up environment variables.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlsolaris.pod b/Master/tlpkg/tlperl/lib/pods/perlsolaris.pod
new file mode 100644
index 00000000000..427e08de6ed
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlsolaris.pod
@@ -0,0 +1,690 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specifically designed to be readable as is.
+
+=head1 NAME
+
+README.solaris - Perl version 5 on Solaris systems
+
+=head1 DESCRIPTION
+
+This document describes various features of Sun's Solaris operating system
+that will affect how Perl version 5 (hereafter just perl) is
+compiled and/or runs. Some issues relating to the older SunOS 4.x are
+also discussed, though they may be out of date.
+
+For the most part, everything should just work.
+
+Starting with Solaris 8, perl5.00503 (or higher) is supplied with the
+operating system, so you might not even need to build a newer version
+of perl at all. The Sun-supplied version is installed in /usr/perl5
+with /usr/bin/perl pointing to /usr/perl5/bin/perl. Do not disturb
+that installation unless you really know what you are doing. If you
+remove the perl supplied with the OS, you will render some bits of
+your system inoperable. If you wish to install a newer version of perl,
+install it under a different prefix from /usr/perl5. Common prefixes
+to use are /usr/local and /opt/perl.
+
+You may wish to put your version of perl in the PATH of all users by
+changing the link /usr/bin/perl. This is probably OK, as most perl
+scripts shipped with Solaris use an explicit path. (There are a few
+exceptions, such as /usr/bin/rpm2cpio and /etc/rcm/scripts/README, but
+these are also sufficiently generic that the actual version of perl
+probably doesn't matter too much.)
+
+Solaris ships with a range of Solaris-specific modules. If you choose
+to install your own version of perl you will find the source of many of
+these modules is available on CPAN under the Sun::Solaris:: namespace.
+
+Solaris may include two versions of perl, e.g. Solaris 9 includes
+both 5.005_03 and 5.6.1. This is to provide stability across Solaris
+releases, in cases where a later perl version has incompatibilities
+with the version included in the preceeding Solaris release. The
+default perl version will always be the most recent, and in general
+the old version will only be retained for one Solaris release. Note
+also that the default perl will NOT be configured to search for modules
+in the older version, again due to compatibility/stability concerns.
+As a consequence if you upgrade Solaris, you will have to
+rebuild/reinstall any additional CPAN modules that you installed for
+the previous Solaris version. See the CPAN manpage under 'autobundle'
+for a quick way of doing this.
+
+As an interim measure, you may either change the #! line of your
+scripts to specifically refer to the old perl version, e.g. on
+Solaris 9 use #!/usr/perl5/5.00503/bin/perl to use the perl version
+that was the default for Solaris 8, or if you have a large number of
+scripts it may be more convenient to make the old version of perl the
+default on your system. You can do this by changing the appropriate
+symlinks under /usr/perl5 as follows (example for Solaris 9):
+
+ # cd /usr/perl5
+ # rm bin man pod
+ # ln -s ./5.00503/bin
+ # ln -s ./5.00503/man
+ # ln -s ./5.00503/lib/pod
+ # rm /usr/bin/perl
+ # ln -s ../perl5/5.00503/bin/perl /usr/bin/perl
+
+In both cases this should only be considered to be a temporary
+measure - you should upgrade to the later version of perl as soon as
+is practicable.
+
+Note also that the perl command-line utilities (e.g. perldoc) and any
+that are added by modules that you install will be under
+/usr/perl5/bin, so that directory should be added to your PATH.
+
+=head2 Solaris Version Numbers.
+
+For consistency with common usage, perl's Configure script performs
+some minor manipulations on the operating system name and version
+number as reported by uname. Here's a partial translation table:
+
+ Sun: perl's Configure:
+ uname uname -r Name osname osvers
+ SunOS 4.1.3 Solaris 1.1 sunos 4.1.3
+ SunOS 5.6 Solaris 2.6 solaris 2.6
+ SunOS 5.8 Solaris 8 solaris 2.8
+ SunOS 5.9 Solaris 9 solaris 2.9
+ SunOS 5.10 Solaris 10 solaris 2.10
+
+The complete table can be found in the Sun Managers' FAQ
+L<ftp://ftp.cs.toronto.edu/pub/jdd/sunmanagers/faq> under
+"9.1) Which Sun models run which versions of SunOS?".
+
+=head1 RESOURCES
+
+There are many, many sources for Solaris information. A few of the
+important ones for perl:
+
+=over 4
+
+=item Solaris FAQ
+
+The Solaris FAQ is available at
+L<http://www.science.uva.nl/pub/solaris/solaris2.html>.
+
+The Sun Managers' FAQ is available at
+L<ftp://ftp.cs.toronto.edu/pub/jdd/sunmanagers/faq>
+
+=item Precompiled Binaries
+
+Precompiled binaries, links to many sites, and much, much more are
+available at L<http://www.sunfreeware.com/> and
+L<http://www.blastwave.org/>.
+
+=item Solaris Documentation
+
+All Solaris documentation is available on-line at L<http://docs.sun.com/>.
+
+=back
+
+=head1 SETTING UP
+
+=head2 File Extraction Problems on Solaris.
+
+Be sure to use a tar program compiled under Solaris (not SunOS 4.x)
+to extract the perl-5.x.x.tar.gz file. Do not use GNU tar compiled
+for SunOS4 on Solaris. (GNU tar compiled for Solaris should be fine.)
+When you run SunOS4 binaries on Solaris, the run-time system magically
+alters pathnames matching m#lib/locale# so that when tar tries to create
+lib/locale.pm, a file named lib/oldlocale.pm gets created instead.
+If you found this advice too late and used a SunOS4-compiled tar
+anyway, you must find the incorrectly renamed file and move it back
+to lib/locale.pm.
+
+=head2 Compiler and Related Tools on Solaris.
+
+You must use an ANSI C compiler to build perl. Perl can be compiled
+with either Sun's add-on C compiler or with gcc. The C compiler that
+shipped with SunOS4 will not do.
+
+=head3 Include /usr/ccs/bin/ in your PATH.
+
+Several tools needed to build perl are located in /usr/ccs/bin/: ar,
+as, ld, and make. Make sure that /usr/ccs/bin/ is in your PATH.
+
+You need to make sure the following packages are installed
+(this info is extracted from the Solaris FAQ):
+
+for tools (sccs, lex, yacc, make, nm, truss, ld, as): SUNWbtool,
+SUNWsprot, SUNWtoo
+
+for libraries & headers: SUNWhea, SUNWarc, SUNWlibm, SUNWlibms, SUNWdfbh,
+SUNWcg6h, SUNWxwinc, SUNWolinc
+
+for 64 bit development: SUNWarcx, SUNWbtoox, SUNWdplx, SUNWscpux,
+SUNWsprox, SUNWtoox, SUNWlmsx, SUNWlmx, SUNWlibCx
+
+If you are in doubt which package contains a file you are missing,
+try to find an installation that has that file. Then do a
+
+ $ grep /my/missing/file /var/sadm/install/contents
+
+This will display a line like this:
+
+/usr/include/sys/errno.h f none 0644 root bin 7471 37605 956241356 SUNWhea
+
+The last item listed (SUNWhea in this example) is the package you need.
+
+=head3 Avoid /usr/ucb/cc.
+
+You don't need to have /usr/ucb/ in your PATH to build perl. If you
+want /usr/ucb/ in your PATH anyway, make sure that /usr/ucb/ is NOT
+in your PATH before the directory containing the right C compiler.
+
+=head3 Sun's C Compiler
+
+If you use Sun's C compiler, make sure the correct directory
+(usually /opt/SUNWspro/bin/) is in your PATH (before /usr/ucb/).
+
+=head3 GCC
+
+If you use gcc, make sure your installation is recent and complete.
+perl versions since 5.6.0 build fine with gcc > 2.8.1 on Solaris >=
+2.6.
+
+You must Configure perl with
+
+ $ sh Configure -Dcc=gcc
+
+If you don't, you may experience strange build errors.
+
+If you have updated your Solaris version, you may also have to update
+your gcc. For example, if you are running Solaris 2.6 and your gcc is
+installed under /usr/local, check in /usr/local/lib/gcc-lib and make
+sure you have the appropriate directory, sparc-sun-solaris2.6/ or
+i386-pc-solaris2.6/. If gcc's directory is for a different version of
+Solaris than you are running, then you will need to rebuild gcc for
+your new version of Solaris.
+
+You can get a precompiled version of gcc from
+L<http://www.sunfreeware.com/> or L<http://www.blastwave.org/>. Make
+sure you pick up the package for your Solaris release.
+
+If you wish to use gcc to build add-on modules for use with the perl
+shipped with Solaris, you should use the Solaris::PerlGcc module
+which is available from CPAN. The perl shipped with Solaris
+is configured and built with the Sun compilers, and the compiler
+configuration information stored in Config.pm is therefore only
+relevant to the Sun compilers. The Solaris:PerlGcc module contains a
+replacement Config.pm that is correct for gcc - see the module for
+details.
+
+=head3 GNU as and GNU ld
+
+The following information applies to gcc version 2. Volunteers to
+update it as appropropriate for gcc version 3 would be appreciated.
+
+The versions of as and ld supplied with Solaris work fine for building
+perl. There is normally no need to install the GNU versions to
+compile perl.
+
+If you decide to ignore this advice and use the GNU versions anyway,
+then be sure that they are relatively recent. Versions newer than 2.7
+are apparently new enough. Older versions may have trouble with
+dynamic loading.
+
+If you wish to use GNU ld, then you need to pass it the -Wl,-E flag.
+The hints/solaris_2.sh file tries to do this automatically by setting
+the following Configure variables:
+
+ ccdlflags="$ccdlflags -Wl,-E"
+ lddlflags="$lddlflags -Wl,-E -G"
+
+However, over the years, changes in gcc, GNU ld, and Solaris ld have made
+it difficult to automatically detect which ld ultimately gets called.
+You may have to manually edit config.sh and add the -Wl,-E flags
+yourself, or else run Configure interactively and add the flags at the
+appropriate prompts.
+
+If your gcc is configured to use GNU as and ld but you want to use the
+Solaris ones instead to build perl, then you'll need to add
+-B/usr/ccs/bin/ to the gcc command line. One convenient way to do
+that is with
+
+ $ sh Configure -Dcc='gcc -B/usr/ccs/bin/'
+
+Note that the trailing slash is required. This will result in some
+harmless warnings as Configure is run:
+
+ gcc: file path prefix `/usr/ccs/bin/' never used
+
+These messages may safely be ignored.
+(Note that for a SunOS4 system, you must use -B/bin/ instead.)
+
+Alternatively, you can use the GCC_EXEC_PREFIX environment variable to
+ensure that Sun's as and ld are used. Consult your gcc documentation
+for further information on the -B option and the GCC_EXEC_PREFIX variable.
+
+=head3 Sun and GNU make
+
+The make under /usr/ccs/bin works fine for building perl. If you
+have the Sun C compilers, you will also have a parallel version of
+make (dmake). This works fine to build perl, but can sometimes cause
+problems when running 'make test' due to underspecified dependencies
+between the different test harness files. The same problem can also
+affect the building of some add-on modules, so in those cases either
+specify '-m serial' on the dmake command line, or use
+/usr/ccs/bin/make instead. If you wish to use GNU make, be sure that
+the set-group-id bit is not set. If it is, then arrange your PATH so
+that /usr/ccs/bin/make is before GNU make or else have the system
+administrator disable the set-group-id bit on GNU make.
+
+=head3 Avoid libucb.
+
+Solaris provides some BSD-compatibility functions in /usr/ucblib/libucb.a.
+Perl will not build and run correctly if linked against -lucb since it
+contains routines that are incompatible with the standard Solaris libc.
+Normally this is not a problem since the solaris hints file prevents
+Configure from even looking in /usr/ucblib for libraries, and also
+explicitly omits -lucb.
+
+=head2 Environment for Compiling perl on Solaris
+
+=head3 PATH
+
+Make sure your PATH includes the compiler (/opt/SUNWspro/bin/ if you're
+using Sun's compiler) as well as /usr/ccs/bin/ to pick up the other
+development tools (such as make, ar, as, and ld). Make sure your path
+either doesn't include /usr/ucb or that it includes it after the
+compiler and compiler tools and other standard Solaris directories.
+You definitely don't want /usr/ucb/cc.
+
+=head3 LD_LIBRARY_PATH
+
+If you have the LD_LIBRARY_PATH environment variable set, be sure that
+it does NOT include /lib or /usr/lib. If you will be building
+extensions that call third-party shared libraries (e.g. Berkeley DB)
+then make sure that your LD_LIBRARY_PATH environment variable includes
+the directory with that library (e.g. /usr/local/lib).
+
+If you get an error message
+
+ dlopen: stub interception failed
+
+it is probably because your LD_LIBRARY_PATH environment variable
+includes a directory which is a symlink to /usr/lib (such as /lib).
+The reason this causes a problem is quite subtle. The file
+libdl.so.1.0 actually *only* contains functions which generate 'stub
+interception failed' errors! The runtime linker intercepts links to
+"/usr/lib/libdl.so.1.0" and links in internal implementations of those
+functions instead. [Thanks to Tim Bunce for this explanation.]
+
+=head1 RUN CONFIGURE.
+
+See the INSTALL file for general information regarding Configure.
+Only Solaris-specific issues are discussed here. Usually, the
+defaults should be fine.
+
+=head2 64-bit perl on Solaris.
+
+See the INSTALL file for general information regarding 64-bit compiles.
+In general, the defaults should be fine for most people.
+
+By default, perl-5.6.0 (or later) is compiled as a 32-bit application
+with largefile and long-long support.
+
+=head3 General 32-bit vs. 64-bit issues.
+
+Solaris 7 and above will run in either 32 bit or 64 bit mode on SPARC
+CPUs, via a reboot. You can build 64 bit apps whilst running 32 bit
+mode and vice-versa. 32 bit apps will run under Solaris running in
+either 32 or 64 bit mode. 64 bit apps require Solaris to be running
+64 bit mode.
+
+Existing 32 bit apps are properly known as LP32, i.e. Longs and
+Pointers are 32 bit. 64-bit apps are more properly known as LP64.
+The discriminating feature of a LP64 bit app is its ability to utilise a
+64-bit address space. It is perfectly possible to have a LP32 bit app
+that supports both 64-bit integers (long long) and largefiles (> 2GB),
+and this is the default for perl-5.6.0.
+
+For a more complete explanation of 64-bit issues, see the
+"Solaris 64-bit Developer's Guide" at L<http://docs.sun.com/>
+
+You can detect the OS mode using "isainfo -v", e.g.
+
+ $ isainfo -v # Ultra 30 in 64 bit mode
+ 64-bit sparcv9 applications
+ 32-bit sparc applications
+
+By default, perl will be compiled as a 32-bit application. Unless
+you want to allocate more than ~ 4GB of memory inside perl, or unless
+you need more than 255 open file descriptors, you probably don't need
+perl to be a 64-bit app.
+
+=head3 Large File Support
+
+For Solaris 2.6 and onwards, there are two different ways for 32-bit
+applications to manipulate large files (files whose size is > 2GByte).
+(A 64-bit application automatically has largefile support built in
+by default.)
+
+First is the "transitional compilation environment", described in
+lfcompile64(5). According to the man page,
+
+ The transitional compilation environment exports all the
+ explicit 64-bit functions (xxx64()) and types in addition to
+ all the regular functions (xxx()) and types. Both xxx() and
+ xxx64() functions are available to the program source. A
+ 32-bit application must use the xxx64() functions in order
+ to access large files. See the lf64(5) manual page for a
+ complete listing of the 64-bit transitional interfaces.
+
+The transitional compilation environment is obtained with the
+following compiler and linker flags:
+
+ getconf LFS64_CFLAGS -D_LARGEFILE64_SOURCE
+ getconf LFS64_LDFLAG # nothing special needed
+ getconf LFS64_LIBS # nothing special needed
+
+Second is the "large file compilation environment", described in
+lfcompile(5). According to the man page,
+
+ Each interface named xxx() that needs to access 64-bit entities
+ to access large files maps to a xxx64() call in the
+ resulting binary. All relevant data types are defined to be
+ of correct size (for example, off_t has a typedef definition
+ for a 64-bit entity).
+
+ An application compiled in this environment is able to use
+ the xxx() source interfaces to access both large and small
+ files, rather than having to explicitly utilize the transitional
+ xxx64() interface calls to access large files.
+
+Two exceptions are fseek() and ftell(). 32-bit applications should
+use fseeko(3C) and ftello(3C). These will get automatically mapped
+to fseeko64() and ftello64().
+
+The large file compilation environment is obtained with
+
+ getconf LFS_CFLAGS -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64
+ getconf LFS_LDFLAGS # nothing special needed
+ getconf LFS_LIBS # nothing special needed
+
+By default, perl uses the large file compilation environment and
+relies on Solaris to do the underlying mapping of interfaces.
+
+=head3 Building an LP64 perl
+
+To compile a 64-bit application on an UltraSparc with a recent Sun Compiler,
+you need to use the flag "-xarch=v9". getconf(1) will tell you this, e.g.
+
+ $ getconf -a | grep v9
+ XBS5_LP64_OFF64_CFLAGS: -xarch=v9
+ XBS5_LP64_OFF64_LDFLAGS: -xarch=v9
+ XBS5_LP64_OFF64_LINTFLAGS: -xarch=v9
+ XBS5_LPBIG_OFFBIG_CFLAGS: -xarch=v9
+ XBS5_LPBIG_OFFBIG_LDFLAGS: -xarch=v9
+ XBS5_LPBIG_OFFBIG_LINTFLAGS: -xarch=v9
+ _XBS5_LP64_OFF64_CFLAGS: -xarch=v9
+ _XBS5_LP64_OFF64_LDFLAGS: -xarch=v9
+ _XBS5_LP64_OFF64_LINTFLAGS: -xarch=v9
+ _XBS5_LPBIG_OFFBIG_CFLAGS: -xarch=v9
+ _XBS5_LPBIG_OFFBIG_LDFLAGS: -xarch=v9
+ _XBS5_LPBIG_OFFBIG_LINTFLAGS: -xarch=v9
+
+This flag is supported in Sun WorkShop Compilers 5.0 and onwards
+(now marketed under the name Forte) when used on Solaris 7 or later on
+UltraSparc systems.
+
+If you are using gcc, you would need to use -mcpu=v9 -m64 instead. This
+option is not yet supported as of gcc 2.95.2; from install/SPECIFIC
+in that release:
+
+ GCC version 2.95 is not able to compile code correctly for sparc64
+ targets. Users of the Linux kernel, at least, can use the sparc32
+ program to start up a new shell invocation with an environment that
+ causes configure to recognize (via uname -a) the system as sparc-*-*
+ instead.
+
+All this should be handled automatically by the hints file, if
+requested.
+
+=head3 Long Doubles.
+
+As of 5.8.1, long doubles are working if you use the Sun compilers
+(needed for additional math routines not included in libm).
+
+=head2 Threads in perl on Solaris.
+
+It is possible to build a threaded version of perl on Solaris. The entire
+perl thread implementation is still experimental, however, so beware.
+
+=head2 Malloc Issues with perl on Solaris.
+
+Starting from perl 5.7.1 perl uses the Solaris malloc, since the perl
+malloc breaks when dealing with more than 2GB of memory, and the Solaris
+malloc also seems to be faster.
+
+If you for some reason (such as binary backward compatibility) really
+need to use perl's malloc, you can rebuild perl from the sources
+and Configure the build with
+
+ $ sh Configure -Dusemymalloc
+
+You should not use perl's malloc if you are building with gcc. There
+are reports of core dumps, especially in the PDL module. The problem
+appears to go away under -DDEBUGGING, so it has been difficult to
+track down. Sun's compiler appears to be okay with or without perl's
+malloc. [XXX further investigation is needed here.]
+
+=head1 MAKE PROBLEMS.
+
+=over 4
+
+=item Dynamic Loading Problems With GNU as and GNU ld
+
+If you have problems with dynamic loading using gcc on SunOS or
+Solaris, and you are using GNU as and GNU ld, see the section
+L<"GNU as and GNU ld"> above.
+
+=item ld.so.1: ./perl: fatal: relocation error:
+
+If you get this message on SunOS or Solaris, and you're using gcc,
+it's probably the GNU as or GNU ld problem in the previous item
+L<"GNU as and GNU ld">.
+
+=item dlopen: stub interception failed
+
+The primary cause of the 'dlopen: stub interception failed' message is
+that the LD_LIBRARY_PATH environment variable includes a directory
+which is a symlink to /usr/lib (such as /lib). See
+L<"LD_LIBRARY_PATH"> above.
+
+=item #error "No DATAMODEL_NATIVE specified"
+
+This is a common error when trying to build perl on Solaris 2.6 with a
+gcc installation from Solaris 2.5 or 2.5.1. The Solaris header files
+changed, so you need to update your gcc installation. You can either
+rerun the fixincludes script from gcc or take the opportunity to
+update your gcc installation.
+
+=item sh: ar: not found
+
+This is a message from your shell telling you that the command 'ar'
+was not found. You need to check your PATH environment variable to
+make sure that it includes the directory with the 'ar' command. This
+is a common problem on Solaris, where 'ar' is in the /usr/ccs/bin/
+directory.
+
+=back
+
+=head1 MAKE TEST
+
+=head2 op/stat.t test 4 in Solaris
+
+op/stat.t test 4 may fail if you are on a tmpfs of some sort.
+Building in /tmp sometimes shows this behavior. The
+test suite detects if you are building in /tmp, but it may not be able
+to catch all tmpfs situations.
+
+=head2 nss_delete core dump from op/pwent or op/grent
+
+See L<perlhpux/"nss_delete core dump from op/pwent or op/grent">.
+
+=head1 PREBUILT BINARIES OF PERL FOR SOLARIS.
+
+You can pick up prebuilt binaries for Solaris from
+L<http://www.sunfreeware.com/>, L<http://www.blastwave.org>,
+ActiveState L<http://www.activestate.com/>, and
+L<http://www.perl.com/> under the Binaries list at the top of the
+page. There are probably other sources as well. Please note that
+these sites are under the control of their respective owners, not the
+perl developers.
+
+=head1 RUNTIME ISSUES FOR PERL ON SOLARIS.
+
+=head2 Limits on Numbers of Open Files on Solaris.
+
+The stdio(3C) manpage notes that for LP32 applications, only 255
+files may be opened using fopen(), and only file descriptors 0
+through 255 can be used in a stream. Since perl calls open() and
+then fdopen(3C) with the resulting file descriptor, perl is limited
+to 255 simultaneous open files, even if sysopen() is used. If this
+proves to be an insurmountable problem, you can compile perl as a
+LP64 application, see L<Building an LP64 perl> for details. Note
+also that the default resource limit for open file descriptors on
+Solaris is 255, so you will have to modify your ulimit or rctl
+(Solaris 9 onwards) appropriately.
+
+=head1 SOLARIS-SPECIFIC MODULES.
+
+See the modules under the Solaris:: and Sun::Solaris namespaces on CPAN,
+see L<http://www.cpan.org/modules/by-module/Solaris/> and
+L<http://www.cpan.org/modules/by-module/Sun/>.
+
+=head1 SOLARIS-SPECIFIC PROBLEMS WITH MODULES.
+
+=head2 Proc::ProcessTable on Solaris
+
+Proc::ProcessTable does not compile on Solaris with perl5.6.0 and higher
+if you have LARGEFILES defined. Since largefile support is the
+default in 5.6.0 and later, you have to take special steps to use this
+module.
+
+The problem is that various structures visible via procfs use off_t,
+and if you compile with largefile support these change from 32 bits to
+64 bits. Thus what you get back from procfs doesn't match up with
+the structures in perl, resulting in garbage. See proc(4) for further
+discussion.
+
+A fix for Proc::ProcessTable is to edit Makefile to
+explicitly remove the largefile flags from the ones MakeMaker picks up
+from Config.pm. This will result in Proc::ProcessTable being built
+under the correct environment. Everything should then be OK as long as
+Proc::ProcessTable doesn't try to share off_t's with the rest of perl,
+or if it does they should be explicitly specified as off64_t.
+
+=head2 BSD::Resource on Solaris
+
+BSD::Resource versions earlier than 1.09 do not compile on Solaris
+with perl 5.6.0 and higher, for the same reasons as Proc::ProcessTable.
+BSD::Resource versions starting from 1.09 have a workaround for the problem.
+
+=head2 Net::SSLeay on Solaris
+
+Net::SSLeay requires a /dev/urandom to be present. This device is
+available from Solaris 9 onwards. For earlier Solaris versions you
+can either get the package SUNWski (packaged with several Sun
+software products, for example the Sun WebServer, which is part of
+the Solaris Server Intranet Extension, or the Sun Directory Services,
+part of Solaris for ISPs) or download the ANDIrand package from
+L<http://www.cosy.sbg.ac.at/~andi/>. If you use SUNWski, make a
+symbolic link /dev/urandom pointing to /dev/random. For more details,
+see Document ID27606 entitled "Differing /dev/random support requirements
+within Solaris[TM] Operating Environments", available at
+http://sunsolve.sun.com .
+
+It may be possible to use the Entropy Gathering Daemon (written in
+Perl!), available from L<http://www.lothar.com/tech/crypto/>.
+
+=head1 SunOS 4.x
+
+In SunOS 4.x you most probably want to use the SunOS ld, /usr/bin/ld,
+since the more recent versions of GNU ld (like 2.13) do not seem to
+work for building Perl anymore. When linking the extensions, the
+GNU ld gets very unhappy and spews a lot of errors like this
+
+ ... relocation truncated to fit: BASE13 ...
+
+and dies. Therefore the SunOS 4.1 hints file explicitly sets the
+ld to be /usr/bin/ld.
+
+As of Perl 5.8.1 the dynamic loading of libraries (DynaLoader, XSLoader)
+also seems to have become broken in in SunOS 4.x. Therefore the default
+is to build Perl statically.
+
+Running the test suite in SunOS 4.1 is a bit tricky since the
+F<lib/Tie/File/t/09_gen_rs> test hangs (subtest #51, FWIW) for some
+unknown reason. Just stop the test and kill that particular Perl
+process.
+
+There are various other failures, that as of SunOS 4.1.4 and gcc 3.2.2
+look a lot like gcc bugs. Many of the failures happen in the Encode
+tests, where for example when the test expects "0" you get "&#48;"
+which should after a little squinting look very odd indeed.
+Another example is earlier in F<t/run/fresh_perl> where chr(0xff) is
+expected but the test fails because the result is chr(0xff). Exactly.
+
+This is the "make test" result from the said combination:
+
+ Failed 27 test scripts out of 745, 96.38% okay.
+
+Running the C<harness> is painful because of the many failing
+Unicode-related tests will output megabytes of failure messages,
+but if one patiently waits, one gets these results:
+
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ -----------------------------------------------------------------------------
+ ...
+ ../ext/Encode/t/at-cn.t 4 1024 29 4 13.79% 14-17
+ ../ext/Encode/t/at-tw.t 10 2560 17 10 58.82% 2 4 6 8 10 12
+ 14-17
+ ../ext/Encode/t/enc_data.t 29 7424 ?? ?? % ??
+ ../ext/Encode/t/enc_eucjp.t 29 7424 ?? ?? % ??
+ ../ext/Encode/t/enc_module.t 29 7424 ?? ?? % ??
+ ../ext/Encode/t/encoding.t 29 7424 ?? ?? % ??
+ ../ext/Encode/t/grow.t 12 3072 24 12 50.00% 2 4 6 8 10 12 14
+ 16 18 20 22 24
+ Failed Test Stat Wstat Total Fail Failed List of Failed
+ ------------------------------------------------------------------------------
+ ../ext/Encode/t/guess.t 255 65280 29 40 137.93% 10-29
+ ../ext/Encode/t/jperl.t 29 7424 15 30 200.00% 1-15
+ ../ext/Encode/t/mime-header.t 2 512 10 2 20.00% 2-3
+ ../ext/Encode/t/perlio.t 22 5632 38 22 57.89% 1-4 9-16 19-20
+ 23-24 27-32
+ ../ext/List/Util/t/shuffle.t 0 139 ?? ?? % ??
+ ../ext/PerlIO/t/encoding.t 14 1 7.14% 11
+ ../ext/PerlIO/t/fallback.t 9 2 22.22% 3 5
+ ../ext/Socket/t/socketpair.t 0 2 45 70 155.56% 11-45
+ ../lib/CPAN/t/vcmp.t 30 1 3.33% 25
+ ../lib/Tie/File/t/09_gen_rs.t 0 15 ?? ?? % ??
+ ../lib/Unicode/Collate/t/test.t 199 30 15.08% 7 26-27 71-75
+ 81-88 95 101
+ 103-104 106 108-
+ 109 122 124 161
+ 169-172
+ ../lib/sort.t 0 139 119 26 21.85% 107-119
+ op/alarm.t 4 1 25.00% 4
+ op/utfhash.t 97 1 1.03% 31
+ run/fresh_perl.t 91 1 1.10% 32
+ uni/tr_7jis.t ?? ?? % ??
+ uni/tr_eucjp.t 29 7424 6 12 200.00% 1-6
+ uni/tr_sjis.t 29 7424 6 12 200.00% 1-6
+ 56 tests and 467 subtests skipped.
+ Failed 27/811 test scripts, 96.67% okay. 1383/75399 subtests failed, 98.17% okay.
+
+The alarm() test failure is caused by system() apparently blocking
+alarm(). That is probably a libc bug, and given that SunOS 4.x
+has been end-of-lifed years ago, don't hold your breath for a fix.
+In addition to that, don't try anything too Unicode-y, especially
+with Encode, and you should be fine in SunOS 4.x.
+
+=head1 AUTHOR
+
+The original was written by Andy Dougherty F<doughera@lafayette.edu>
+drawing heavily on advice from Alan Burlison, Nick Ing-Simmons, Tim Bunce,
+and many other Solaris users over the years.
+
+Please report any errors, updates, or suggestions to F<perlbug@perl.org>.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlstyle.pod b/Master/tlpkg/tlperl/lib/pods/perlstyle.pod
new file mode 100644
index 00000000000..37dfaaf1413
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlstyle.pod
@@ -0,0 +1,303 @@
+=head1 NAME
+
+perlstyle - Perl style guide
+
+=head1 DESCRIPTION
+
+Each programmer will, of course, have his or her own preferences in
+regards to formatting, but there are some general guidelines that will
+make your programs easier to read, understand, and maintain.
+
+The most important thing is to run your programs under the B<-w>
+flag at all times. You may turn it off explicitly for particular
+portions of code via the C<no warnings> pragma or the C<$^W> variable
+if you must. You should also always run under C<use strict> or know the
+reason why not. The C<use sigtrap> and even C<use diagnostics> pragmas
+may also prove useful.
+
+Regarding aesthetics of code lay out, about the only thing Larry
+cares strongly about is that the closing curly bracket of
+a multi-line BLOCK should line up with the keyword that started the construct.
+Beyond that, he has other preferences that aren't so strong:
+
+=over 4
+
+=item *
+
+4-column indent.
+
+=item *
+
+Opening curly on same line as keyword, if possible, otherwise line up.
+
+=item *
+
+Space before the opening curly of a multi-line BLOCK.
+
+=item *
+
+One-line BLOCK may be put on one line, including curlies.
+
+=item *
+
+No space before the semicolon.
+
+=item *
+
+Semicolon omitted in "short" one-line BLOCK.
+
+=item *
+
+Space around most operators.
+
+=item *
+
+Space around a "complex" subscript (inside brackets).
+
+=item *
+
+Blank lines between chunks that do different things.
+
+=item *
+
+Uncuddled elses.
+
+=item *
+
+No space between function name and its opening parenthesis.
+
+=item *
+
+Space after each comma.
+
+=item *
+
+Long lines broken after an operator (except C<and> and C<or>).
+
+=item *
+
+Space after last parenthesis matching on current line.
+
+=item *
+
+Line up corresponding items vertically.
+
+=item *
+
+Omit redundant punctuation as long as clarity doesn't suffer.
+
+=back
+
+Larry has his reasons for each of these things, but he doesn't claim that
+everyone else's mind works the same as his does.
+
+Here are some other more substantive style issues to think about:
+
+=over 4
+
+=item *
+
+Just because you I<CAN> do something a particular way doesn't mean that
+you I<SHOULD> do it that way. Perl is designed to give you several
+ways to do anything, so consider picking the most readable one. For
+instance
+
+ open(FOO,$foo) || die "Can't open $foo: $!";
+
+is better than
+
+ die "Can't open $foo: $!" unless open(FOO,$foo);
+
+because the second way hides the main point of the statement in a
+modifier. On the other hand
+
+ print "Starting analysis\n" if $verbose;
+
+is better than
+
+ $verbose && print "Starting analysis\n";
+
+because the main point isn't whether the user typed B<-v> or not.
+
+Similarly, just because an operator lets you assume default arguments
+doesn't mean that you have to make use of the defaults. The defaults
+are there for lazy systems programmers writing one-shot programs. If
+you want your program to be readable, consider supplying the argument.
+
+Along the same lines, just because you I<CAN> omit parentheses in many
+places doesn't mean that you ought to:
+
+ return print reverse sort num values %array;
+ return print(reverse(sort num (values(%array))));
+
+When in doubt, parenthesize. At the very least it will let some poor
+schmuck bounce on the % key in B<vi>.
+
+Even if you aren't in doubt, consider the mental welfare of the person
+who has to maintain the code after you, and who will probably put
+parentheses in the wrong place.
+
+=item *
+
+Don't go through silly contortions to exit a loop at the top or the
+bottom, when Perl provides the C<last> operator so you can exit in
+the middle. Just "outdent" it a little to make it more visible:
+
+ LINE:
+ for (;;) {
+ statements;
+ last LINE if $foo;
+ next LINE if /^#/;
+ statements;
+ }
+
+=item *
+
+Don't be afraid to use loop labels--they're there to enhance
+readability as well as to allow multilevel loop breaks. See the
+previous example.
+
+=item *
+
+Avoid using C<grep()> (or C<map()>) or `backticks` in a void context, that is,
+when you just throw away their return values. Those functions all
+have return values, so use them. Otherwise use a C<foreach()> loop or
+the C<system()> function instead.
+
+=item *
+
+For portability, when using features that may not be implemented on
+every machine, test the construct in an eval to see if it fails. If
+you know what version or patchlevel a particular feature was
+implemented, you can test C<$]> (C<$PERL_VERSION> in C<English>) to see if it
+will be there. The C<Config> module will also let you interrogate values
+determined by the B<Configure> program when Perl was installed.
+
+=item *
+
+Choose mnemonic identifiers. If you can't remember what mnemonic means,
+you've got a problem.
+
+=item *
+
+While short identifiers like C<$gotit> are probably ok, use underscores to
+separate words in longer identifiers. It is generally easier to read
+C<$var_names_like_this> than C<$VarNamesLikeThis>, especially for
+non-native speakers of English. It's also a simple rule that works
+consistently with C<VAR_NAMES_LIKE_THIS>.
+
+Package names are sometimes an exception to this rule. Perl informally
+reserves lowercase module names for "pragma" modules like C<integer> and
+C<strict>. Other modules should begin with a capital letter and use mixed
+case, but probably without underscores due to limitations in primitive
+file systems' representations of module names as files that must fit into a
+few sparse bytes.
+
+=item *
+
+You may find it helpful to use letter case to indicate the scope
+or nature of a variable. For example:
+
+ $ALL_CAPS_HERE constants only (beware clashes with perl vars!)
+ $Some_Caps_Here package-wide global/static
+ $no_caps_here function scope my() or local() variables
+
+Function and method names seem to work best as all lowercase.
+E.g., C<$obj-E<gt>as_string()>.
+
+You can use a leading underscore to indicate that a variable or
+function should not be used outside the package that defined it.
+
+=item *
+
+If you have a really hairy regular expression, use the C</x> modifier and
+put in some whitespace to make it look a little less like line noise.
+Don't use slash as a delimiter when your regexp has slashes or backslashes.
+
+=item *
+
+Use the new C<and> and C<or> operators to avoid having to parenthesize
+list operators so much, and to reduce the incidence of punctuation
+operators like C<&&> and C<||>. Call your subroutines as if they were
+functions or list operators to avoid excessive ampersands and parentheses.
+
+=item *
+
+Use here documents instead of repeated C<print()> statements.
+
+=item *
+
+Line up corresponding things vertically, especially if it'd be too long
+to fit on one line anyway.
+
+ $IDX = $ST_MTIME;
+ $IDX = $ST_ATIME if $opt_u;
+ $IDX = $ST_CTIME if $opt_c;
+ $IDX = $ST_SIZE if $opt_s;
+
+ mkdir $tmpdir, 0700 or die "can't mkdir $tmpdir: $!";
+ chdir($tmpdir) or die "can't chdir $tmpdir: $!";
+ mkdir 'tmp', 0777 or die "can't mkdir $tmpdir/tmp: $!";
+
+=item *
+
+Always check the return codes of system calls. Good error messages should
+go to C<STDERR>, include which program caused the problem, what the failed
+system call and arguments were, and (VERY IMPORTANT) should contain the
+standard system error message for what went wrong. Here's a simple but
+sufficient example:
+
+ opendir(D, $dir) or die "can't opendir $dir: $!";
+
+=item *
+
+Line up your transliterations when it makes sense:
+
+ tr [abc]
+ [xyz];
+
+=item *
+
+Think about reusability. Why waste brainpower on a one-shot when you
+might want to do something like it again? Consider generalizing your
+code. Consider writing a module or object class. Consider making your
+code run cleanly with C<use strict> and C<use warnings> (or B<-w>) in
+effect. Consider giving away your code. Consider changing your whole
+world view. Consider... oh, never mind.
+
+=item *
+
+Try to document your code and use Pod formatting in a consistent way. Here
+are commonly expected conventions:
+
+=over 4
+
+=item *
+
+use C<CE<lt>E<gt>> for function, variable and module names (and more
+generally anything that can be considered part of code, like filehandles
+or specific values). Note that function names are considered more readable
+with parentheses after their name, that is C<function()>.
+
+=item *
+
+use C<BE<lt>E<gt>> for commands names like B<cat> or B<grep>.
+
+=item *
+
+use C<FE<lt>E<gt>> or C<CE<lt>E<gt>> for file names. C<FE<lt>E<gt>> should
+be the only Pod code for file names, but as most Pod formatters render it
+as italic, Unix and Windows paths with their slashes and backslashes may
+be less readable, and better rendered with C<CE<lt>E<gt>>.
+
+=back
+
+=item *
+
+Be consistent.
+
+=item *
+
+Be nice.
+
+=back
diff --git a/Master/tlpkg/tlperl/lib/pods/perlsub.pod b/Master/tlpkg/tlperl/lib/pods/perlsub.pod
new file mode 100644
index 00000000000..325c823bff4
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlsub.pod
@@ -0,0 +1,1513 @@
+=head1 NAME
+X<subroutine> X<function>
+
+perlsub - Perl subroutines
+
+=head1 SYNOPSIS
+
+To declare subroutines:
+X<subroutine, declaration> X<sub>
+
+ sub NAME; # A "forward" declaration.
+ sub NAME(PROTO); # ditto, but with prototypes
+ sub NAME : ATTRS; # with attributes
+ sub NAME(PROTO) : ATTRS; # with attributes and prototypes
+
+ sub NAME BLOCK # A declaration and a definition.
+ sub NAME(PROTO) BLOCK # ditto, but with prototypes
+ sub NAME : ATTRS BLOCK # with attributes
+ sub NAME(PROTO) : ATTRS BLOCK # with prototypes and attributes
+
+To define an anonymous subroutine at runtime:
+X<subroutine, anonymous>
+
+ $subref = sub BLOCK; # no proto
+ $subref = sub (PROTO) BLOCK; # with proto
+ $subref = sub : ATTRS BLOCK; # with attributes
+ $subref = sub (PROTO) : ATTRS BLOCK; # with proto and attributes
+
+To import subroutines:
+X<import>
+
+ use MODULE qw(NAME1 NAME2 NAME3);
+
+To call subroutines:
+X<subroutine, call> X<call>
+
+ NAME(LIST); # & is optional with parentheses.
+ NAME LIST; # Parentheses optional if predeclared/imported.
+ &NAME(LIST); # Circumvent prototypes.
+ &NAME; # Makes current @_ visible to called subroutine.
+
+=head1 DESCRIPTION
+
+Like many languages, Perl provides for user-defined subroutines.
+These may be located anywhere in the main program, loaded in from
+other files via the C<do>, C<require>, or C<use> keywords, or
+generated on the fly using C<eval> or anonymous subroutines.
+You can even call a function indirectly using a variable containing
+its name or a CODE reference.
+
+The Perl model for function call and return values is simple: all
+functions are passed as parameters one single flat list of scalars, and
+all functions likewise return to their caller one single flat list of
+scalars. Any arrays or hashes in these call and return lists will
+collapse, losing their identities--but you may always use
+pass-by-reference instead to avoid this. Both call and return lists may
+contain as many or as few scalar elements as you'd like. (Often a
+function without an explicit return statement is called a subroutine, but
+there's really no difference from Perl's perspective.)
+X<subroutine, parameter> X<parameter>
+
+Any arguments passed in show up in the array C<@_>. Therefore, if
+you called a function with two arguments, those would be stored in
+C<$_[0]> and C<$_[1]>. The array C<@_> is a local array, but its
+elements are aliases for the actual scalar parameters. In particular,
+if an element C<$_[0]> is updated, the corresponding argument is
+updated (or an error occurs if it is not updatable). If an argument
+is an array or hash element which did not exist when the function
+was called, that element is created only when (and if) it is modified
+or a reference to it is taken. (Some earlier versions of Perl
+created the element whether or not the element was assigned to.)
+Assigning to the whole array C<@_> removes that aliasing, and does
+not update any arguments.
+X<subroutine, argument> X<argument> X<@_>
+
+A C<return> statement may be used to exit a subroutine, optionally
+specifying the returned value, which will be evaluated in the
+appropriate context (list, scalar, or void) depending on the context of
+the subroutine call. If you specify no return value, the subroutine
+returns an empty list in list context, the undefined value in scalar
+context, or nothing in void context. If you return one or more
+aggregates (arrays and hashes), these will be flattened together into
+one large indistinguishable list.
+
+If no C<return> is found and if the last statement is an expression, its
+value is returned. If the last statement is a loop control structure
+like a C<foreach> or a C<while>, the returned value is unspecified. The
+empty sub returns the empty list.
+X<subroutine, return value> X<return value> X<return>
+
+Perl does not have named formal parameters. In practice all you
+do is assign to a C<my()> list of these. Variables that aren't
+declared to be private are global variables. For gory details
+on creating private variables, see L<"Private Variables via my()">
+and L<"Temporary Values via local()">. To create protected
+environments for a set of functions in a separate package (and
+probably a separate file), see L<perlmod/"Packages">.
+X<formal parameter> X<parameter, formal>
+
+Example:
+
+ sub max {
+ my $max = shift(@_);
+ foreach $foo (@_) {
+ $max = $foo if $max < $foo;
+ }
+ return $max;
+ }
+ $bestday = max($mon,$tue,$wed,$thu,$fri);
+
+Example:
+
+ # get a line, combining continuation lines
+ # that start with whitespace
+
+ sub get_line {
+ $thisline = $lookahead; # global variables!
+ LINE: while (defined($lookahead = <STDIN>)) {
+ if ($lookahead =~ /^[ \t]/) {
+ $thisline .= $lookahead;
+ }
+ else {
+ last LINE;
+ }
+ }
+ return $thisline;
+ }
+
+ $lookahead = <STDIN>; # get first line
+ while (defined($line = get_line())) {
+ ...
+ }
+
+Assigning to a list of private variables to name your arguments:
+
+ sub maybeset {
+ my($key, $value) = @_;
+ $Foo{$key} = $value unless $Foo{$key};
+ }
+
+Because the assignment copies the values, this also has the effect
+of turning call-by-reference into call-by-value. Otherwise a
+function is free to do in-place modifications of C<@_> and change
+its caller's values.
+X<call-by-reference> X<call-by-value>
+
+ upcase_in($v1, $v2); # this changes $v1 and $v2
+ sub upcase_in {
+ for (@_) { tr/a-z/A-Z/ }
+ }
+
+You aren't allowed to modify constants in this way, of course. If an
+argument were actually literal and you tried to change it, you'd take a
+(presumably fatal) exception. For example, this won't work:
+X<call-by-reference> X<call-by-value>
+
+ upcase_in("frederick");
+
+It would be much safer if the C<upcase_in()> function
+were written to return a copy of its parameters instead
+of changing them in place:
+
+ ($v3, $v4) = upcase($v1, $v2); # this doesn't change $v1 and $v2
+ sub upcase {
+ return unless defined wantarray; # void context, do nothing
+ my @parms = @_;
+ for (@parms) { tr/a-z/A-Z/ }
+ return wantarray ? @parms : $parms[0];
+ }
+
+Notice how this (unprototyped) function doesn't care whether it was
+passed real scalars or arrays. Perl sees all arguments as one big,
+long, flat parameter list in C<@_>. This is one area where
+Perl's simple argument-passing style shines. The C<upcase()>
+function would work perfectly well without changing the C<upcase()>
+definition even if we fed it things like this:
+
+ @newlist = upcase(@list1, @list2);
+ @newlist = upcase( split /:/, $var );
+
+Do not, however, be tempted to do this:
+
+ (@a, @b) = upcase(@list1, @list2);
+
+Like the flattened incoming parameter list, the return list is also
+flattened on return. So all you have managed to do here is stored
+everything in C<@a> and made C<@b> empty. See
+L<Pass by Reference> for alternatives.
+
+A subroutine may be called using an explicit C<&> prefix. The
+C<&> is optional in modern Perl, as are parentheses if the
+subroutine has been predeclared. The C<&> is I<not> optional
+when just naming the subroutine, such as when it's used as
+an argument to defined() or undef(). Nor is it optional when you
+want to do an indirect subroutine call with a subroutine name or
+reference using the C<&$subref()> or C<&{$subref}()> constructs,
+although the C<< $subref->() >> notation solves that problem.
+See L<perlref> for more about all that.
+X<&>
+
+Subroutines may be called recursively. If a subroutine is called
+using the C<&> form, the argument list is optional, and if omitted,
+no C<@_> array is set up for the subroutine: the C<@_> array at the
+time of the call is visible to subroutine instead. This is an
+efficiency mechanism that new users may wish to avoid.
+X<recursion>
+
+ &foo(1,2,3); # pass three arguments
+ foo(1,2,3); # the same
+
+ foo(); # pass a null list
+ &foo(); # the same
+
+ &foo; # foo() get current args, like foo(@_) !!
+ foo; # like foo() IFF sub foo predeclared, else "foo"
+
+Not only does the C<&> form make the argument list optional, it also
+disables any prototype checking on arguments you do provide. This
+is partly for historical reasons, and partly for having a convenient way
+to cheat if you know what you're doing. See L<Prototypes> below.
+X<&>
+
+Subroutines whose names are in all upper case are reserved to the Perl
+core, as are modules whose names are in all lower case. A subroutine in
+all capitals is a loosely-held convention meaning it will be called
+indirectly by the run-time system itself, usually due to a triggered event.
+Subroutines that do special, pre-defined things include C<AUTOLOAD>, C<CLONE>,
+C<DESTROY> plus all functions mentioned in L<perltie> and L<PerlIO::via>.
+
+The C<BEGIN>, C<UNITCHECK>, C<CHECK>, C<INIT> and C<END> subroutines
+are not so much subroutines as named special code blocks, of which you
+can have more than one in a package, and which you can B<not> call
+explicitly. See L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">
+
+=head2 Private Variables via my()
+X<my> X<variable, lexical> X<lexical> X<lexical variable> X<scope, lexical>
+X<lexical scope> X<attributes, my>
+
+Synopsis:
+
+ my $foo; # declare $foo lexically local
+ my (@wid, %get); # declare list of variables local
+ my $foo = "flurp"; # declare $foo lexical, and init it
+ my @oof = @bar; # declare @oof lexical, and init it
+ my $x : Foo = $y; # similar, with an attribute applied
+
+B<WARNING>: The use of attribute lists on C<my> declarations is still
+evolving. The current semantics and interface are subject to change.
+See L<attributes> and L<Attribute::Handlers>.
+
+The C<my> operator declares the listed variables to be lexically
+confined to the enclosing block, conditional (C<if/unless/elsif/else>),
+loop (C<for/foreach/while/until/continue>), subroutine, C<eval>,
+or C<do/require/use>'d file. If more than one value is listed, the
+list must be placed in parentheses. All listed elements must be
+legal lvalues. Only alphanumeric identifiers may be lexically
+scoped--magical built-ins like C<$/> must currently be C<local>ized
+with C<local> instead.
+
+Unlike dynamic variables created by the C<local> operator, lexical
+variables declared with C<my> are totally hidden from the outside
+world, including any called subroutines. This is true if it's the
+same subroutine called from itself or elsewhere--every call gets
+its own copy.
+X<local>
+
+This doesn't mean that a C<my> variable declared in a statically
+enclosing lexical scope would be invisible. Only dynamic scopes
+are cut off. For example, the C<bumpx()> function below has access
+to the lexical $x variable because both the C<my> and the C<sub>
+occurred at the same scope, presumably file scope.
+
+ my $x = 10;
+ sub bumpx { $x++ }
+
+An C<eval()>, however, can see lexical variables of the scope it is
+being evaluated in, so long as the names aren't hidden by declarations within
+the C<eval()> itself. See L<perlref>.
+X<eval, scope of>
+
+The parameter list to my() may be assigned to if desired, which allows you
+to initialize your variables. (If no initializer is given for a
+particular variable, it is created with the undefined value.) Commonly
+this is used to name input parameters to a subroutine. Examples:
+
+ $arg = "fred"; # "global" variable
+ $n = cube_root(27);
+ print "$arg thinks the root is $n\n";
+ fred thinks the root is 3
+
+ sub cube_root {
+ my $arg = shift; # name doesn't matter
+ $arg **= 1/3;
+ return $arg;
+ }
+
+The C<my> is simply a modifier on something you might assign to. So when
+you do assign to variables in its argument list, C<my> doesn't
+change whether those variables are viewed as a scalar or an array. So
+
+ my ($foo) = <STDIN>; # WRONG?
+ my @FOO = <STDIN>;
+
+both supply a list context to the right-hand side, while
+
+ my $foo = <STDIN>;
+
+supplies a scalar context. But the following declares only one variable:
+
+ my $foo, $bar = 1; # WRONG
+
+That has the same effect as
+
+ my $foo;
+ $bar = 1;
+
+The declared variable is not introduced (is not visible) until after
+the current statement. Thus,
+
+ my $x = $x;
+
+can be used to initialize a new $x with the value of the old $x, and
+the expression
+
+ my $x = 123 and $x == 123
+
+is false unless the old $x happened to have the value C<123>.
+
+Lexical scopes of control structures are not bounded precisely by the
+braces that delimit their controlled blocks; control expressions are
+part of that scope, too. Thus in the loop
+
+ while (my $line = <>) {
+ $line = lc $line;
+ } continue {
+ print $line;
+ }
+
+the scope of $line extends from its declaration throughout the rest of
+the loop construct (including the C<continue> clause), but not beyond
+it. Similarly, in the conditional
+
+ if ((my $answer = <STDIN>) =~ /^yes$/i) {
+ user_agrees();
+ } elsif ($answer =~ /^no$/i) {
+ user_disagrees();
+ } else {
+ chomp $answer;
+ die "'$answer' is neither 'yes' nor 'no'";
+ }
+
+the scope of $answer extends from its declaration through the rest
+of that conditional, including any C<elsif> and C<else> clauses,
+but not beyond it. See L<perlsyn/"Simple statements"> for information
+on the scope of variables in statements with modifiers.
+
+The C<foreach> loop defaults to scoping its index variable dynamically
+in the manner of C<local>. However, if the index variable is
+prefixed with the keyword C<my>, or if there is already a lexical
+by that name in scope, then a new lexical is created instead. Thus
+in the loop
+X<foreach> X<for>
+
+ for my $i (1, 2, 3) {
+ some_function();
+ }
+
+the scope of $i extends to the end of the loop, but not beyond it,
+rendering the value of $i inaccessible within C<some_function()>.
+X<foreach> X<for>
+
+Some users may wish to encourage the use of lexically scoped variables.
+As an aid to catching implicit uses to package variables,
+which are always global, if you say
+
+ use strict 'vars';
+
+then any variable mentioned from there to the end of the enclosing
+block must either refer to a lexical variable, be predeclared via
+C<our> or C<use vars>, or else must be fully qualified with the package name.
+A compilation error results otherwise. An inner block may countermand
+this with C<no strict 'vars'>.
+
+A C<my> has both a compile-time and a run-time effect. At compile
+time, the compiler takes notice of it. The principal usefulness
+of this is to quiet C<use strict 'vars'>, but it is also essential
+for generation of closures as detailed in L<perlref>. Actual
+initialization is delayed until run time, though, so it gets executed
+at the appropriate time, such as each time through a loop, for
+example.
+
+Variables declared with C<my> are not part of any package and are therefore
+never fully qualified with the package name. In particular, you're not
+allowed to try to make a package variable (or other global) lexical:
+
+ my $pack::var; # ERROR! Illegal syntax
+
+In fact, a dynamic variable (also known as package or global variables)
+are still accessible using the fully qualified C<::> notation even while a
+lexical of the same name is also visible:
+
+ package main;
+ local $x = 10;
+ my $x = 20;
+ print "$x and $::x\n";
+
+That will print out C<20> and C<10>.
+
+You may declare C<my> variables at the outermost scope of a file
+to hide any such identifiers from the world outside that file. This
+is similar in spirit to C's static variables when they are used at
+the file level. To do this with a subroutine requires the use of
+a closure (an anonymous function that accesses enclosing lexicals).
+If you want to create a private subroutine that cannot be called
+from outside that block, it can declare a lexical variable containing
+an anonymous sub reference:
+
+ my $secret_version = '1.001-beta';
+ my $secret_sub = sub { print $secret_version };
+ &$secret_sub();
+
+As long as the reference is never returned by any function within the
+module, no outside module can see the subroutine, because its name is not in
+any package's symbol table. Remember that it's not I<REALLY> called
+C<$some_pack::secret_version> or anything; it's just $secret_version,
+unqualified and unqualifiable.
+
+This does not work with object methods, however; all object methods
+have to be in the symbol table of some package to be found. See
+L<perlref/"Function Templates"> for something of a work-around to
+this.
+
+=head2 Persistent Private Variables
+X<state> X<state variable> X<static> X<variable, persistent> X<variable, static> X<closure>
+
+There are two ways to build persistent private variables in Perl 5.10.
+First, you can simply use the C<state> feature. Or, you can use closures,
+if you want to stay compatible with releases older than 5.10.
+
+=head3 Persistent variables via state()
+
+Beginning with perl 5.9.4, you can declare variables with the C<state>
+keyword in place of C<my>. For that to work, though, you must have
+enabled that feature beforehand, either by using the C<feature> pragma, or
+by using C<-E> on one-liners. (see L<feature>)
+
+For example, the following code maintains a private counter, incremented
+each time the gimme_another() function is called:
+
+ use feature 'state';
+ sub gimme_another { state $x; return ++$x }
+
+Also, since C<$x> is lexical, it can't be reached or modified by any Perl
+code outside.
+
+When combined with variable declaration, simple scalar assignment to C<state>
+variables (as in C<state $x = 42>) is executed only the first time. When such
+statements are evaluated subsequent times, the assignment is ignored. The
+behavior of this sort of assignment to non-scalar variables is undefined.
+
+=head3 Persistent variables with closures
+
+Just because a lexical variable is lexically (also called statically)
+scoped to its enclosing block, C<eval>, or C<do> FILE, this doesn't mean that
+within a function it works like a C static. It normally works more
+like a C auto, but with implicit garbage collection.
+
+Unlike local variables in C or C++, Perl's lexical variables don't
+necessarily get recycled just because their scope has exited.
+If something more permanent is still aware of the lexical, it will
+stick around. So long as something else references a lexical, that
+lexical won't be freed--which is as it should be. You wouldn't want
+memory being free until you were done using it, or kept around once you
+were done. Automatic garbage collection takes care of this for you.
+
+This means that you can pass back or save away references to lexical
+variables, whereas to return a pointer to a C auto is a grave error.
+It also gives us a way to simulate C's function statics. Here's a
+mechanism for giving a function private variables with both lexical
+scoping and a static lifetime. If you do want to create something like
+C's static variables, just enclose the whole function in an extra block,
+and put the static variable outside the function but in the block.
+
+ {
+ my $secret_val = 0;
+ sub gimme_another {
+ return ++$secret_val;
+ }
+ }
+ # $secret_val now becomes unreachable by the outside
+ # world, but retains its value between calls to gimme_another
+
+If this function is being sourced in from a separate file
+via C<require> or C<use>, then this is probably just fine. If it's
+all in the main program, you'll need to arrange for the C<my>
+to be executed early, either by putting the whole block above
+your main program, or more likely, placing merely a C<BEGIN>
+code block around it to make sure it gets executed before your program
+starts to run:
+
+ BEGIN {
+ my $secret_val = 0;
+ sub gimme_another {
+ return ++$secret_val;
+ }
+ }
+
+See L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END"> about the
+special triggered code blocks, C<BEGIN>, C<UNITCHECK>, C<CHECK>,
+C<INIT> and C<END>.
+
+If declared at the outermost scope (the file scope), then lexicals
+work somewhat like C's file statics. They are available to all
+functions in that same file declared below them, but are inaccessible
+from outside that file. This strategy is sometimes used in modules
+to create private variables that the whole module can see.
+
+=head2 Temporary Values via local()
+X<local> X<scope, dynamic> X<dynamic scope> X<variable, local>
+X<variable, temporary>
+
+B<WARNING>: In general, you should be using C<my> instead of C<local>, because
+it's faster and safer. Exceptions to this include the global punctuation
+variables, global filehandles and formats, and direct manipulation of the
+Perl symbol table itself. C<local> is mostly used when the current value
+of a variable must be visible to called subroutines.
+
+Synopsis:
+
+ # localization of values
+
+ local $foo; # make $foo dynamically local
+ local (@wid, %get); # make list of variables local
+ local $foo = "flurp"; # make $foo dynamic, and init it
+ local @oof = @bar; # make @oof dynamic, and init it
+
+ local $hash{key} = "val"; # sets a local value for this hash entry
+ delete local $hash{key}; # delete this entry for the current block
+ local ($cond ? $v1 : $v2); # several types of lvalues support
+ # localization
+
+ # localization of symbols
+
+ local *FH; # localize $FH, @FH, %FH, &FH ...
+ local *merlyn = *randal; # now $merlyn is really $randal, plus
+ # @merlyn is really @randal, etc
+ local *merlyn = 'randal'; # SAME THING: promote 'randal' to *randal
+ local *merlyn = \$randal; # just alias $merlyn, not @merlyn etc
+
+A C<local> modifies its listed variables to be "local" to the
+enclosing block, C<eval>, or C<do FILE>--and to I<any subroutine
+called from within that block>. A C<local> just gives temporary
+values to global (meaning package) variables. It does I<not> create
+a local variable. This is known as dynamic scoping. Lexical scoping
+is done with C<my>, which works more like C's auto declarations.
+
+Some types of lvalues can be localized as well : hash and array elements
+and slices, conditionals (provided that their result is always
+localizable), and symbolic references. As for simple variables, this
+creates new, dynamically scoped values.
+
+If more than one variable or expression is given to C<local>, they must be
+placed in parentheses. This operator works
+by saving the current values of those variables in its argument list on a
+hidden stack and restoring them upon exiting the block, subroutine, or
+eval. This means that called subroutines can also reference the local
+variable, but not the global one. The argument list may be assigned to if
+desired, which allows you to initialize your local variables. (If no
+initializer is given for a particular variable, it is created with an
+undefined value.)
+
+Because C<local> is a run-time operator, it gets executed each time
+through a loop. Consequently, it's more efficient to localize your
+variables outside the loop.
+
+=head3 Grammatical note on local()
+X<local, context>
+
+A C<local> is simply a modifier on an lvalue expression. When you assign to
+a C<local>ized variable, the C<local> doesn't change whether its list is viewed
+as a scalar or an array. So
+
+ local($foo) = <STDIN>;
+ local @FOO = <STDIN>;
+
+both supply a list context to the right-hand side, while
+
+ local $foo = <STDIN>;
+
+supplies a scalar context.
+
+=head3 Localization of special variables
+X<local, special variable>
+
+If you localize a special variable, you'll be giving a new value to it,
+but its magic won't go away. That means that all side-effects related
+to this magic still work with the localized value.
+
+This feature allows code like this to work :
+
+ # Read the whole contents of FILE in $slurp
+ { local $/ = undef; $slurp = <FILE>; }
+
+Note, however, that this restricts localization of some values ; for
+example, the following statement dies, as of perl 5.9.0, with an error
+I<Modification of a read-only value attempted>, because the $1 variable is
+magical and read-only :
+
+ local $1 = 2;
+
+Similarly, but in a way more difficult to spot, the following snippet will
+die in perl 5.9.0 :
+
+ sub f { local $_ = "foo"; print }
+ for ($1) {
+ # now $_ is aliased to $1, thus is magic and readonly
+ f();
+ }
+
+See next section for an alternative to this situation.
+
+B<WARNING>: Localization of tied arrays and hashes does not currently
+work as described.
+This will be fixed in a future release of Perl; in the meantime, avoid
+code that relies on any particular behaviour of localising tied arrays
+or hashes (localising individual elements is still okay).
+See L<perl58delta/"Localising Tied Arrays and Hashes Is Broken"> for more
+details.
+X<local, tie>
+
+=head3 Localization of globs
+X<local, glob> X<glob>
+
+The construct
+
+ local *name;
+
+creates a whole new symbol table entry for the glob C<name> in the
+current package. That means that all variables in its glob slot ($name,
+@name, %name, &name, and the C<name> filehandle) are dynamically reset.
+
+This implies, among other things, that any magic eventually carried by
+those variables is locally lost. In other words, saying C<local */>
+will not have any effect on the internal value of the input record
+separator.
+
+Notably, if you want to work with a brand new value of the default scalar
+$_, and avoid the potential problem listed above about $_ previously
+carrying a magic value, you should use C<local *_> instead of C<local $_>.
+As of perl 5.9.1, you can also use the lexical form of C<$_> (declaring it
+with C<my $_>), which avoids completely this problem.
+
+=head3 Localization of elements of composite types
+X<local, composite type element> X<local, array element> X<local, hash element>
+
+It's also worth taking a moment to explain what happens when you
+C<local>ize a member of a composite type (i.e. an array or hash element).
+In this case, the element is C<local>ized I<by name>. This means that
+when the scope of the C<local()> ends, the saved value will be
+restored to the hash element whose key was named in the C<local()>, or
+the array element whose index was named in the C<local()>. If that
+element was deleted while the C<local()> was in effect (e.g. by a
+C<delete()> from a hash or a C<shift()> of an array), it will spring
+back into existence, possibly extending an array and filling in the
+skipped elements with C<undef>. For instance, if you say
+
+ %hash = ( 'This' => 'is', 'a' => 'test' );
+ @ary = ( 0..5 );
+ {
+ local($ary[5]) = 6;
+ local($hash{'a'}) = 'drill';
+ while (my $e = pop(@ary)) {
+ print "$e . . .\n";
+ last unless $e > 3;
+ }
+ if (@ary) {
+ $hash{'only a'} = 'test';
+ delete $hash{'a'};
+ }
+ }
+ print join(' ', map { "$_ $hash{$_}" } sort keys %hash),".\n";
+ print "The array has ",scalar(@ary)," elements: ",
+ join(', ', map { defined $_ ? $_ : 'undef' } @ary),"\n";
+
+Perl will print
+
+ 6 . . .
+ 4 . . .
+ 3 . . .
+ This is a test only a test.
+ The array has 6 elements: 0, 1, 2, undef, undef, 5
+
+The behavior of local() on non-existent members of composite
+types is subject to change in future.
+
+=head3 Localized deletion of elements of composite types
+X<delete> X<local, composite type element> X<local, array element> X<local, hash element>
+
+You can use the C<delete local $array[$idx]> and C<delete local $hash{key}>
+constructs to delete a composite type entry for the current block and restore
+it when it ends. They return the array/hash value before the localization,
+which means that they are respectively equivalent to
+
+ do {
+ my $val = $array[$idx];
+ local $array[$idx];
+ delete $array[$idx];
+ $val
+ }
+
+and
+
+ do {
+ my $val = $hash{key};
+ local $hash{key};
+ delete $hash{key};
+ $val
+ }
+
+except that for those the C<local> is scoped to the C<do> block. Slices are
+also accepted.
+
+ my %hash = (
+ a => [ 7, 8, 9 ],
+ b => 1,
+ )
+
+ {
+ my $a = delete local $hash{a};
+ # $a is [ 7, 8, 9 ]
+ # %hash is (b => 1)
+
+ {
+ my @nums = delete local @$a[0, 2]
+ # @nums is (7, 9)
+ # $a is [ undef, 8 ]
+
+ $a[0] = 999; # will be erased when the scope ends
+ }
+ # $a is back to [ 7, 8, 9 ]
+
+ }
+ # %hash is back to its original state
+
+=head2 Lvalue subroutines
+X<lvalue> X<subroutine, lvalue>
+
+B<WARNING>: Lvalue subroutines are still experimental and the
+implementation may change in future versions of Perl.
+
+It is possible to return a modifiable value from a subroutine.
+To do this, you have to declare the subroutine to return an lvalue.
+
+ my $val;
+ sub canmod : lvalue {
+ # return $val; this doesn't work, don't say "return"
+ $val;
+ }
+ sub nomod {
+ $val;
+ }
+
+ canmod() = 5; # assigns to $val
+ nomod() = 5; # ERROR
+
+The scalar/list context for the subroutine and for the right-hand
+side of assignment is determined as if the subroutine call is replaced
+by a scalar. For example, consider:
+
+ data(2,3) = get_data(3,4);
+
+Both subroutines here are called in a scalar context, while in:
+
+ (data(2,3)) = get_data(3,4);
+
+and in:
+
+ (data(2),data(3)) = get_data(3,4);
+
+all the subroutines are called in a list context.
+
+=over 4
+
+=item Lvalue subroutines are EXPERIMENTAL
+
+They appear to be convenient, but there are several reasons to be
+circumspect.
+
+You can't use the return keyword, you must pass out the value before
+falling out of subroutine scope. (see comment in example above). This
+is usually not a problem, but it disallows an explicit return out of a
+deeply nested loop, which is sometimes a nice way out.
+
+They violate encapsulation. A normal mutator can check the supplied
+argument before setting the attribute it is protecting, an lvalue
+subroutine never gets that chance. Consider;
+
+ my $some_array_ref = []; # protected by mutators ??
+
+ sub set_arr { # normal mutator
+ my $val = shift;
+ die("expected array, you supplied ", ref $val)
+ unless ref $val eq 'ARRAY';
+ $some_array_ref = $val;
+ }
+ sub set_arr_lv : lvalue { # lvalue mutator
+ $some_array_ref;
+ }
+
+ # set_arr_lv cannot stop this !
+ set_arr_lv() = { a => 1 };
+
+=back
+
+=head2 Passing Symbol Table Entries (typeglobs)
+X<typeglob> X<*>
+
+B<WARNING>: The mechanism described in this section was originally
+the only way to simulate pass-by-reference in older versions of
+Perl. While it still works fine in modern versions, the new reference
+mechanism is generally easier to work with. See below.
+
+Sometimes you don't want to pass the value of an array to a subroutine
+but rather the name of it, so that the subroutine can modify the global
+copy of it rather than working with a local copy. In perl you can
+refer to all objects of a particular name by prefixing the name
+with a star: C<*foo>. This is often known as a "typeglob", because the
+star on the front can be thought of as a wildcard match for all the
+funny prefix characters on variables and subroutines and such.
+
+When evaluated, the typeglob produces a scalar value that represents
+all the objects of that name, including any filehandle, format, or
+subroutine. When assigned to, it causes the name mentioned to refer to
+whatever C<*> value was assigned to it. Example:
+
+ sub doubleary {
+ local(*someary) = @_;
+ foreach $elem (@someary) {
+ $elem *= 2;
+ }
+ }
+ doubleary(*foo);
+ doubleary(*bar);
+
+Scalars are already passed by reference, so you can modify
+scalar arguments without using this mechanism by referring explicitly
+to C<$_[0]> etc. You can modify all the elements of an array by passing
+all the elements as scalars, but you have to use the C<*> mechanism (or
+the equivalent reference mechanism) to C<push>, C<pop>, or change the size of
+an array. It will certainly be faster to pass the typeglob (or reference).
+
+Even if you don't want to modify an array, this mechanism is useful for
+passing multiple arrays in a single LIST, because normally the LIST
+mechanism will merge all the array values so that you can't extract out
+the individual arrays. For more on typeglobs, see
+L<perldata/"Typeglobs and Filehandles">.
+
+=head2 When to Still Use local()
+X<local> X<variable, local>
+
+Despite the existence of C<my>, there are still three places where the
+C<local> operator still shines. In fact, in these three places, you
+I<must> use C<local> instead of C<my>.
+
+=over 4
+
+=item 1.
+
+You need to give a global variable a temporary value, especially $_.
+
+The global variables, like C<@ARGV> or the punctuation variables, must be
+C<local>ized with C<local()>. This block reads in F</etc/motd>, and splits
+it up into chunks separated by lines of equal signs, which are placed
+in C<@Fields>.
+
+ {
+ local @ARGV = ("/etc/motd");
+ local $/ = undef;
+ local $_ = <>;
+ @Fields = split /^\s*=+\s*$/;
+ }
+
+It particular, it's important to C<local>ize $_ in any routine that assigns
+to it. Look out for implicit assignments in C<while> conditionals.
+
+=item 2.
+
+You need to create a local file or directory handle or a local function.
+
+A function that needs a filehandle of its own must use
+C<local()> on a complete typeglob. This can be used to create new symbol
+table entries:
+
+ sub ioqueue {
+ local (*READER, *WRITER); # not my!
+ pipe (READER, WRITER) or die "pipe: $!";
+ return (*READER, *WRITER);
+ }
+ ($head, $tail) = ioqueue();
+
+See the Symbol module for a way to create anonymous symbol table
+entries.
+
+Because assignment of a reference to a typeglob creates an alias, this
+can be used to create what is effectively a local function, or at least,
+a local alias.
+
+ {
+ local *grow = \&shrink; # only until this block exists
+ grow(); # really calls shrink()
+ move(); # if move() grow()s, it shrink()s too
+ }
+ grow(); # get the real grow() again
+
+See L<perlref/"Function Templates"> for more about manipulating
+functions by name in this way.
+
+=item 3.
+
+You want to temporarily change just one element of an array or hash.
+
+You can C<local>ize just one element of an aggregate. Usually this
+is done on dynamics:
+
+ {
+ local $SIG{INT} = 'IGNORE';
+ funct(); # uninterruptible
+ }
+ # interruptibility automatically restored here
+
+But it also works on lexically declared aggregates. Prior to 5.005,
+this operation could on occasion misbehave.
+
+=back
+
+=head2 Pass by Reference
+X<pass by reference> X<pass-by-reference> X<reference>
+
+If you want to pass more than one array or hash into a function--or
+return them from it--and have them maintain their integrity, then
+you're going to have to use an explicit pass-by-reference. Before you
+do that, you need to understand references as detailed in L<perlref>.
+This section may not make much sense to you otherwise.
+
+Here are a few simple examples. First, let's pass in several arrays
+to a function and have it C<pop> all of then, returning a new list
+of all their former last elements:
+
+ @tailings = popmany ( \@a, \@b, \@c, \@d );
+
+ sub popmany {
+ my $aref;
+ my @retlist = ();
+ foreach $aref ( @_ ) {
+ push @retlist, pop @$aref;
+ }
+ return @retlist;
+ }
+
+Here's how you might write a function that returns a
+list of keys occurring in all the hashes passed to it:
+
+ @common = inter( \%foo, \%bar, \%joe );
+ sub inter {
+ my ($k, $href, %seen); # locals
+ foreach $href (@_) {
+ while ( $k = each %$href ) {
+ $seen{$k}++;
+ }
+ }
+ return grep { $seen{$_} == @_ } keys %seen;
+ }
+
+So far, we're using just the normal list return mechanism.
+What happens if you want to pass or return a hash? Well,
+if you're using only one of them, or you don't mind them
+concatenating, then the normal calling convention is ok, although
+a little expensive.
+
+Where people get into trouble is here:
+
+ (@a, @b) = func(@c, @d);
+or
+ (%a, %b) = func(%c, %d);
+
+That syntax simply won't work. It sets just C<@a> or C<%a> and
+clears the C<@b> or C<%b>. Plus the function didn't get passed
+into two separate arrays or hashes: it got one long list in C<@_>,
+as always.
+
+If you can arrange for everyone to deal with this through references, it's
+cleaner code, although not so nice to look at. Here's a function that
+takes two array references as arguments, returning the two array elements
+in order of how many elements they have in them:
+
+ ($aref, $bref) = func(\@c, \@d);
+ print "@$aref has more than @$bref\n";
+ sub func {
+ my ($cref, $dref) = @_;
+ if (@$cref > @$dref) {
+ return ($cref, $dref);
+ } else {
+ return ($dref, $cref);
+ }
+ }
+
+It turns out that you can actually do this also:
+
+ (*a, *b) = func(\@c, \@d);
+ print "@a has more than @b\n";
+ sub func {
+ local (*c, *d) = @_;
+ if (@c > @d) {
+ return (\@c, \@d);
+ } else {
+ return (\@d, \@c);
+ }
+ }
+
+Here we're using the typeglobs to do symbol table aliasing. It's
+a tad subtle, though, and also won't work if you're using C<my>
+variables, because only globals (even in disguise as C<local>s)
+are in the symbol table.
+
+If you're passing around filehandles, you could usually just use the bare
+typeglob, like C<*STDOUT>, but typeglobs references work, too.
+For example:
+
+ splutter(\*STDOUT);
+ sub splutter {
+ my $fh = shift;
+ print $fh "her um well a hmmm\n";
+ }
+
+ $rec = get_rec(\*STDIN);
+ sub get_rec {
+ my $fh = shift;
+ return scalar <$fh>;
+ }
+
+If you're planning on generating new filehandles, you could do this.
+Notice to pass back just the bare *FH, not its reference.
+
+ sub openit {
+ my $path = shift;
+ local *FH;
+ return open (FH, $path) ? *FH : undef;
+ }
+
+=head2 Prototypes
+X<prototype> X<subroutine, prototype>
+
+Perl supports a very limited kind of compile-time argument checking
+using function prototyping. If you declare
+
+ sub mypush (\@@)
+
+then C<mypush()> takes arguments exactly like C<push()> does. The
+function declaration must be visible at compile time. The prototype
+affects only interpretation of new-style calls to the function,
+where new-style is defined as not using the C<&> character. In
+other words, if you call it like a built-in function, then it behaves
+like a built-in function. If you call it like an old-fashioned
+subroutine, then it behaves like an old-fashioned subroutine. It
+naturally falls out from this rule that prototypes have no influence
+on subroutine references like C<\&foo> or on indirect subroutine
+calls like C<&{$subref}> or C<< $subref->() >>.
+
+Method calls are not influenced by prototypes either, because the
+function to be called is indeterminate at compile time, since
+the exact code called depends on inheritance.
+
+Because the intent of this feature is primarily to let you define
+subroutines that work like built-in functions, here are prototypes
+for some other functions that parse almost exactly like the
+corresponding built-in.
+
+ Declared as Called as
+
+ sub mylink ($$) mylink $old, $new
+ sub myvec ($$$) myvec $var, $offset, 1
+ sub myindex ($$;$) myindex &getstring, "substr"
+ sub mysyswrite ($$$;$) mysyswrite $buf, 0, length($buf) - $off, $off
+ sub myreverse (@) myreverse $a, $b, $c
+ sub myjoin ($@) myjoin ":", $a, $b, $c
+ sub mypop (\@) mypop @array
+ sub mysplice (\@$$@) mysplice @array, 0, 2, @pushme
+ sub mykeys (\%) mykeys %{$hashref}
+ sub myopen (*;$) myopen HANDLE, $name
+ sub mypipe (**) mypipe READHANDLE, WRITEHANDLE
+ sub mygrep (&@) mygrep { /foo/ } $a, $b, $c
+ sub myrand (;$) myrand 42
+ sub mytime () mytime
+
+Any backslashed prototype character represents an actual argument
+that absolutely must start with that character. The value passed
+as part of C<@_> will be a reference to the actual argument given
+in the subroutine call, obtained by applying C<\> to that argument.
+
+You can also backslash several argument types simultaneously by using
+the C<\[]> notation:
+
+ sub myref (\[$@%&*])
+
+will allow calling myref() as
+
+ myref $var
+ myref @array
+ myref %hash
+ myref &sub
+ myref *glob
+
+and the first argument of myref() will be a reference to
+a scalar, an array, a hash, a code, or a glob.
+
+Unbackslashed prototype characters have special meanings. Any
+unbackslashed C<@> or C<%> eats all remaining arguments, and forces
+list context. An argument represented by C<$> forces scalar context. An
+C<&> requires an anonymous subroutine, which, if passed as the first
+argument, does not require the C<sub> keyword or a subsequent comma.
+
+A C<*> allows the subroutine to accept a bareword, constant, scalar expression,
+typeglob, or a reference to a typeglob in that slot. The value will be
+available to the subroutine either as a simple scalar, or (in the latter
+two cases) as a reference to the typeglob. If you wish to always convert
+such arguments to a typeglob reference, use Symbol::qualify_to_ref() as
+follows:
+
+ use Symbol 'qualify_to_ref';
+
+ sub foo (*) {
+ my $fh = qualify_to_ref(shift, caller);
+ ...
+ }
+
+A semicolon (C<;>) separates mandatory arguments from optional arguments.
+It is redundant before C<@> or C<%>, which gobble up everything else.
+
+As the last character of a prototype, or just before a semicolon, you can
+use C<_> in place of C<$>: if this argument is not provided, C<$_> will be
+used instead.
+
+Note how the last three examples in the table above are treated
+specially by the parser. C<mygrep()> is parsed as a true list
+operator, C<myrand()> is parsed as a true unary operator with unary
+precedence the same as C<rand()>, and C<mytime()> is truly without
+arguments, just like C<time()>. That is, if you say
+
+ mytime +2;
+
+you'll get C<mytime() + 2>, not C<mytime(2)>, which is how it would be parsed
+without a prototype.
+
+The interesting thing about C<&> is that you can generate new syntax with it,
+provided it's in the initial position:
+X<&>
+
+ sub try (&@) {
+ my($try,$catch) = @_;
+ eval { &$try };
+ if ($@) {
+ local $_ = $@;
+ &$catch;
+ }
+ }
+ sub catch (&) { $_[0] }
+
+ try {
+ die "phooey";
+ } catch {
+ /phooey/ and print "unphooey\n";
+ };
+
+That prints C<"unphooey">. (Yes, there are still unresolved
+issues having to do with visibility of C<@_>. I'm ignoring that
+question for the moment. (But note that if we make C<@_> lexically
+scoped, those anonymous subroutines can act like closures... (Gee,
+is this sounding a little Lispish? (Never mind.))))
+
+And here's a reimplementation of the Perl C<grep> operator:
+X<grep>
+
+ sub mygrep (&@) {
+ my $code = shift;
+ my @result;
+ foreach $_ (@_) {
+ push(@result, $_) if &$code;
+ }
+ @result;
+ }
+
+Some folks would prefer full alphanumeric prototypes. Alphanumerics have
+been intentionally left out of prototypes for the express purpose of
+someday in the future adding named, formal parameters. The current
+mechanism's main goal is to let module writers provide better diagnostics
+for module users. Larry feels the notation quite understandable to Perl
+programmers, and that it will not intrude greatly upon the meat of the
+module, nor make it harder to read. The line noise is visually
+encapsulated into a small pill that's easy to swallow.
+
+If you try to use an alphanumeric sequence in a prototype you will
+generate an optional warning - "Illegal character in prototype...".
+Unfortunately earlier versions of Perl allowed the prototype to be
+used as long as its prefix was a valid prototype. The warning may be
+upgraded to a fatal error in a future version of Perl once the
+majority of offending code is fixed.
+
+It's probably best to prototype new functions, not retrofit prototyping
+into older ones. That's because you must be especially careful about
+silent impositions of differing list versus scalar contexts. For example,
+if you decide that a function should take just one parameter, like this:
+
+ sub func ($) {
+ my $n = shift;
+ print "you gave me $n\n";
+ }
+
+and someone has been calling it with an array or expression
+returning a list:
+
+ func(@foo);
+ func( split /:/ );
+
+Then you've just supplied an automatic C<scalar> in front of their
+argument, which can be more than a bit surprising. The old C<@foo>
+which used to hold one thing doesn't get passed in. Instead,
+C<func()> now gets passed in a C<1>; that is, the number of elements
+in C<@foo>. And the C<split> gets called in scalar context so it
+starts scribbling on your C<@_> parameter list. Ouch!
+
+This is all very powerful, of course, and should be used only in moderation
+to make the world a better place.
+
+=head2 Constant Functions
+X<constant>
+
+Functions with a prototype of C<()> are potential candidates for
+inlining. If the result after optimization and constant folding
+is either a constant or a lexically-scoped scalar which has no other
+references, then it will be used in place of function calls made
+without C<&>. Calls made using C<&> are never inlined. (See
+F<constant.pm> for an easy way to declare most constants.)
+
+The following functions would all be inlined:
+
+ sub pi () { 3.14159 } # Not exact, but close.
+ sub PI () { 4 * atan2 1, 1 } # As good as it gets,
+ # and it's inlined, too!
+ sub ST_DEV () { 0 }
+ sub ST_INO () { 1 }
+
+ sub FLAG_FOO () { 1 << 8 }
+ sub FLAG_BAR () { 1 << 9 }
+ sub FLAG_MASK () { FLAG_FOO | FLAG_BAR }
+
+ sub OPT_BAZ () { not (0x1B58 & FLAG_MASK) }
+
+ sub N () { int(OPT_BAZ) / 3 }
+
+ sub FOO_SET () { 1 if FLAG_MASK & FLAG_FOO }
+
+Be aware that these will not be inlined; as they contain inner scopes,
+the constant folding doesn't reduce them to a single constant:
+
+ sub foo_set () { if (FLAG_MASK & FLAG_FOO) { 1 } }
+
+ sub baz_val () {
+ if (OPT_BAZ) {
+ return 23;
+ }
+ else {
+ return 42;
+ }
+ }
+
+If you redefine a subroutine that was eligible for inlining, you'll get
+a mandatory warning. (You can use this warning to tell whether or not a
+particular subroutine is considered constant.) The warning is
+considered severe enough not to be optional because previously compiled
+invocations of the function will still be using the old value of the
+function. If you need to be able to redefine the subroutine, you need to
+ensure that it isn't inlined, either by dropping the C<()> prototype
+(which changes calling semantics, so beware) or by thwarting the
+inlining mechanism in some other way, such as
+
+ sub not_inlined () {
+ 23 if $];
+ }
+
+=head2 Overriding Built-in Functions
+X<built-in> X<override> X<CORE> X<CORE::GLOBAL>
+
+Many built-in functions may be overridden, though this should be tried
+only occasionally and for good reason. Typically this might be
+done by a package attempting to emulate missing built-in functionality
+on a non-Unix system.
+
+Overriding may be done only by importing the name from a module at
+compile time--ordinary predeclaration isn't good enough. However, the
+C<use subs> pragma lets you, in effect, predeclare subs
+via the import syntax, and these names may then override built-in ones:
+
+ use subs 'chdir', 'chroot', 'chmod', 'chown';
+ chdir $somewhere;
+ sub chdir { ... }
+
+To unambiguously refer to the built-in form, precede the
+built-in name with the special package qualifier C<CORE::>. For example,
+saying C<CORE::open()> always refers to the built-in C<open()>, even
+if the current package has imported some other subroutine called
+C<&open()> from elsewhere. Even though it looks like a regular
+function call, it isn't: you can't take a reference to it, such as
+the incorrect C<\&CORE::open> might appear to produce.
+
+Library modules should not in general export built-in names like C<open>
+or C<chdir> as part of their default C<@EXPORT> list, because these may
+sneak into someone else's namespace and change the semantics unexpectedly.
+Instead, if the module adds that name to C<@EXPORT_OK>, then it's
+possible for a user to import the name explicitly, but not implicitly.
+That is, they could say
+
+ use Module 'open';
+
+and it would import the C<open> override. But if they said
+
+ use Module;
+
+they would get the default imports without overrides.
+
+The foregoing mechanism for overriding built-in is restricted, quite
+deliberately, to the package that requests the import. There is a second
+method that is sometimes applicable when you wish to override a built-in
+everywhere, without regard to namespace boundaries. This is achieved by
+importing a sub into the special namespace C<CORE::GLOBAL::>. Here is an
+example that quite brazenly replaces the C<glob> operator with something
+that understands regular expressions.
+
+ package REGlob;
+ require Exporter;
+ @ISA = 'Exporter';
+ @EXPORT_OK = 'glob';
+
+ sub import {
+ my $pkg = shift;
+ return unless @_;
+ my $sym = shift;
+ my $where = ($sym =~ s/^GLOBAL_// ? 'CORE::GLOBAL' : caller(0));
+ $pkg->export($where, $sym, @_);
+ }
+
+ sub glob {
+ my $pat = shift;
+ my @got;
+ if (opendir my $d, '.') {
+ @got = grep /$pat/, readdir $d;
+ closedir $d;
+ }
+ return @got;
+ }
+ 1;
+
+And here's how it could be (ab)used:
+
+ #use REGlob 'GLOBAL_glob'; # override glob() in ALL namespaces
+ package Foo;
+ use REGlob 'glob'; # override glob() in Foo:: only
+ print for <^[a-z_]+\.pm\$>; # show all pragmatic modules
+
+The initial comment shows a contrived, even dangerous example.
+By overriding C<glob> globally, you would be forcing the new (and
+subversive) behavior for the C<glob> operator for I<every> namespace,
+without the complete cognizance or cooperation of the modules that own
+those namespaces. Naturally, this should be done with extreme caution--if
+it must be done at all.
+
+The C<REGlob> example above does not implement all the support needed to
+cleanly override perl's C<glob> operator. The built-in C<glob> has
+different behaviors depending on whether it appears in a scalar or list
+context, but our C<REGlob> doesn't. Indeed, many perl built-in have such
+context sensitive behaviors, and these must be adequately supported by
+a properly written override. For a fully functional example of overriding
+C<glob>, study the implementation of C<File::DosGlob> in the standard
+library.
+
+When you override a built-in, your replacement should be consistent (if
+possible) with the built-in native syntax. You can achieve this by using
+a suitable prototype. To get the prototype of an overridable built-in,
+use the C<prototype> function with an argument of C<"CORE::builtin_name">
+(see L<perlfunc/prototype>).
+
+Note however that some built-ins can't have their syntax expressed by a
+prototype (such as C<system> or C<chomp>). If you override them you won't
+be able to fully mimic their original syntax.
+
+The built-ins C<do>, C<require> and C<glob> can also be overridden, but due
+to special magic, their original syntax is preserved, and you don't have
+to define a prototype for their replacements. (You can't override the
+C<do BLOCK> syntax, though).
+
+C<require> has special additional dark magic: if you invoke your
+C<require> replacement as C<require Foo::Bar>, it will actually receive
+the argument C<"Foo/Bar.pm"> in @_. See L<perlfunc/require>.
+
+And, as you'll have noticed from the previous example, if you override
+C<glob>, the C<< <*> >> glob operator is overridden as well.
+
+In a similar fashion, overriding the C<readline> function also overrides
+the equivalent I/O operator C<< <FILEHANDLE> >>. Also, overriding
+C<readpipe> also overrides the operators C<``> and C<qx//>.
+
+Finally, some built-ins (e.g. C<exists> or C<grep>) can't be overridden.
+
+=head2 Autoloading
+X<autoloading> X<AUTOLOAD>
+
+If you call a subroutine that is undefined, you would ordinarily
+get an immediate, fatal error complaining that the subroutine doesn't
+exist. (Likewise for subroutines being used as methods, when the
+method doesn't exist in any base class of the class's package.)
+However, if an C<AUTOLOAD> subroutine is defined in the package or
+packages used to locate the original subroutine, then that
+C<AUTOLOAD> subroutine is called with the arguments that would have
+been passed to the original subroutine. The fully qualified name
+of the original subroutine magically appears in the global $AUTOLOAD
+variable of the same package as the C<AUTOLOAD> routine. The name
+is not passed as an ordinary argument because, er, well, just
+because, that's why. (As an exception, a method call to a nonexistent
+C<import> or C<unimport> method is just skipped instead.)
+
+Many C<AUTOLOAD> routines load in a definition for the requested
+subroutine using eval(), then execute that subroutine using a special
+form of goto() that erases the stack frame of the C<AUTOLOAD> routine
+without a trace. (See the source to the standard module documented
+in L<AutoLoader>, for example.) But an C<AUTOLOAD> routine can
+also just emulate the routine and never define it. For example,
+let's pretend that a function that wasn't defined should just invoke
+C<system> with those arguments. All you'd do is:
+
+ sub AUTOLOAD {
+ my $program = $AUTOLOAD;
+ $program =~ s/.*:://;
+ system($program, @_);
+ }
+ date();
+ who('am', 'i');
+ ls('-l');
+
+In fact, if you predeclare functions you want to call that way, you don't
+even need parentheses:
+
+ use subs qw(date who ls);
+ date;
+ who "am", "i";
+ ls '-l';
+
+A more complete example of this is the standard Shell module, which
+can treat undefined subroutine calls as calls to external programs.
+
+Mechanisms are available to help modules writers split their modules
+into autoloadable files. See the standard AutoLoader module
+described in L<AutoLoader> and in L<AutoSplit>, the standard
+SelfLoader modules in L<SelfLoader>, and the document on adding C
+functions to Perl code in L<perlxs>.
+
+=head2 Subroutine Attributes
+X<attribute> X<subroutine, attribute> X<attrs>
+
+A subroutine declaration or definition may have a list of attributes
+associated with it. If such an attribute list is present, it is
+broken up at space or colon boundaries and treated as though a
+C<use attributes> had been seen. See L<attributes> for details
+about what attributes are currently supported.
+Unlike the limitation with the obsolescent C<use attrs>, the
+C<sub : ATTRLIST> syntax works to associate the attributes with
+a pre-declaration, and not just with a subroutine definition.
+
+The attributes must be valid as simple identifier names (without any
+punctuation other than the '_' character). They may have a parameter
+list appended, which is only checked for whether its parentheses ('(',')')
+nest properly.
+
+Examples of valid syntax (even though the attributes are unknown):
+
+ sub fnord (&\%) : switch(10,foo(7,3)) : expensive;
+ sub plugh () : Ugly('\(") :Bad;
+ sub xyzzy : _5x5 { ... }
+
+Examples of invalid syntax:
+
+ sub fnord : switch(10,foo(); # ()-string not balanced
+ sub snoid : Ugly('('); # ()-string not balanced
+ sub xyzzy : 5x5; # "5x5" not a valid identifier
+ sub plugh : Y2::north; # "Y2::north" not a simple identifier
+ sub snurt : foo + bar; # "+" not a colon or space
+
+The attribute list is passed as a list of constant strings to the code
+which associates them with the subroutine. In particular, the second example
+of valid syntax above currently looks like this in terms of how it's
+parsed and invoked:
+
+ use attributes __PACKAGE__, \&plugh, q[Ugly('\(")], 'Bad';
+
+For further details on attribute lists and their manipulation,
+see L<attributes> and L<Attribute::Handlers>.
+
+=head1 SEE ALSO
+
+See L<perlref/"Function Templates"> for more about references and closures.
+See L<perlxs> if you'd like to learn about calling C subroutines from Perl.
+See L<perlembed> if you'd like to learn about calling Perl subroutines from C.
+See L<perlmod> to learn about bundling up your functions in separate files.
+See L<perlmodlib> to learn what library modules come standard on your system.
+See L<perltoot> to learn how to make object method calls.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlsymbian.pod b/Master/tlpkg/tlperl/lib/pods/perlsymbian.pod
new file mode 100644
index 00000000000..341c0269fb5
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlsymbian.pod
@@ -0,0 +1,433 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.symbian - Perl version 5 on Symbian OS
+
+=head1 DESCRIPTION
+
+This document describes various features of the Symbian operating
+system that will affect how Perl version 5 (hereafter just Perl)
+is compiled and/or runs.
+
+B<NOTE: this port (as of 0.4.1) does not compile into a Symbian
+OS GUI application, but instead it results in a Symbian DLL.>
+The DLL includes a C++ class called CPerlBase, which one can then
+(derive from and) use to embed Perl into applications, see F<symbian/README>.
+
+The base port of Perl to Symbian only implements the basic POSIX-like
+functionality; it does not implement any further Symbian or Series 60,
+Series 80, or UIQ bindings for Perl.
+
+It is also possible to generate Symbian executables for "miniperl"
+and "perl", but since there is no standard command line interface
+for Symbian (nor full keyboards in the devices), these are useful
+mainly as demonstrations.
+
+=head2 Compiling Perl on Symbian
+
+(0) You need to have the appropriate Symbian SDK installed.
+
+ These instructions have been tested under various Nokia Series 60
+ Symbian SDKs (1.2 to 2.6, 2.8 should also work, 1.2 compiles but
+ does not work), Series 80 2.0, and Nokia 7710 (Series 90) SDK.
+ You can get the SDKs from Forum Nokia (http://www.forum.nokia.com/).
+ A very rough port ("it compiles") to UIQ 2.1 has also been made.
+
+ A prerequisite for any of the SDKs is to install ActivePerl
+ from ActiveState, http://www.activestate.com/Products/ActivePerl/
+
+ Having the SDK installed also means that you need to have either
+ the Metrowerks CodeWarrior installed (2.8 and 3.0 were used in testing)
+ or the Microsoft Visual C++ 6.0 installed (SP3 minimum, SP5 recommended).
+
+ Note that for example the Series 60 2.0 VC SDK installation talks
+ about ActivePerl build 518, which does no more (as of mid-2005) exist
+ at the ActiveState website. The ActivePerl 5.8.4 build 810 was
+ used successfully for compiling Perl on Symbian. The 5.6.x ActivePerls
+ do not work.
+
+ Other SDKs or compilers like Visual.NET, command-line-only
+ Visual.NET, Borland, GnuPoc, or sdk2unix have not been tried.
+
+ These instructions almost certainly won't work with older Symbian
+ releases or other SDKs. Patches to get this port running in other
+ releases, SDKs, compilers, platforms, or devices are naturally welcome.
+
+(1) Get a Perl source code distribution (for example the file
+ perl-5.9.2.tar.gz is fine) from http://www.cpan.org/src/
+ and unpack it in your the C:/Symbian directory of your Windows
+ system.
+
+(2) Change to the perl source directory.
+
+ cd c:\Symbian\perl-5.x.x
+
+(3) Run the following script using the perl coming with the SDK
+
+ perl symbian\config.pl
+
+ You must use the cmd.exe, the Cygwin shell will not work.
+ The PATH must include the SDK tools, including a Perl,
+ which should be the case under cmd.exe. If you do not
+ have that, see the end of symbian\sdk.pl for notes of
+ how your environment should be set up for Symbian compiles.
+
+(4) Build the project, either by
+
+ make all
+
+ in cmd.exe or by using either the Metrowerks CodeWarrior
+ or the Visual C++ 6.0, or the Visual Studio 8 (the Visual C++
+ 2005 Express Edition works fine).
+
+ If you use the VC IDE, you will have to run F<symbian\config.pl>
+ first using the cmd.exe, and then run 'make win.mf vc6.mf' to generate
+ the VC6 makefiles and workspaces. "make vc6" will compile for the VC6,
+ and "make cw" for the CodeWarrior.
+
+ The following SDK and compiler configurations and Nokia phones were
+ tested at some point in time (+ = compiled and PerlApp run, - = not),
+ both for Perl 5.8.x and 5.9.x:
+
+ SDK | VC | CW |
+ --------+----+----+---
+ S60 1.2 | + | + | 3650 (*)
+ S60 2.0 | + | + | 6600
+ S60 2.1 | - | + | 6670
+ S60 2.6 | + | + | 6630
+ S60 2.8 | + | + | (not tested in a device)
+ S80 2.6 | - | + | 9300
+ S90 1.1 | + | - | 7710
+ UIQ 2.1 | - | + | (not tested in a device)
+
+ (*) Compiles but does not work, unfortunately, a problem with Symbian.
+
+ If you are using the 'make' directly, it is the GNU make from the SDKs,
+ and it will invoke the right make commands for the Windows emulator
+ build and the Arm target builds ('thumb' by default) as necessary.
+
+ The build scripts assume the 'absolute style' SDK installs under C:,
+ the 'subst style' will not work.
+
+ If using the VC IDE, to build use for example the File->Open Workspace->
+ C:\Symbian\8.0a\S60_2nd_FP2\epoc32\build\symbian\perl\perl\wins\perl.dsw
+ The emulator binaries will appear in the same directory.
+
+ If using the VC IDE, you will a lot of warnings in the beginning of
+ the build because a lot of headers mentioned by the source cannot
+ be found, but this is not serious since those headers are not used.
+
+ The Metrowerks will give a lot of warnings about unused variables and
+ empty declarations, you can ignore those.
+
+ When the Windows and Arm DLLs are built do not be scared by a very long
+ messages whizzing by: it is the "export freeze" phase where the whole
+ (rather large) API of Perl is listed.
+
+ Once the build is completed you need to create the DLL SIS file by
+
+ make perldll.sis
+
+ which will create the file perlXYZ.sis (the XYZ being the Perl version)
+ which you can then install into your Symbian device: an easy way
+ to do this is to send them via Bluetooth or infrared and just open
+ the messages.
+
+ Since the total size of all Perl SIS files once installed is
+ over 2 MB, it is recommended to do the installation into a
+ memory card (drive E:) instead of the C: drive.
+
+ The size of the perlXYZ.SIS is about 370 kB but once it is in the
+ device it is about one 750 kB (according to the application manager).
+
+ The perlXYZ.sis includes only the Perl DLL: to create an additional
+ SIS file which includes some of the standard (pure) Perl libraries,
+ issue the command
+
+ make perllib.sis
+
+ Some of the standard Perl libraries are included, but not all:
+ see L</HISTORY> or F<symbian\install.cfg> for more details
+ (250 kB -> 700 kB).
+
+ Some of the standard Perl XS extensions (see L</HISTORY> are
+ also available:
+
+ make perlext.sis
+
+ which will create perlXYZext.sis (290 kB -> 770 kB).
+
+ To compile the demonstration application PerlApp you need first to
+ install the Perl headers under the SDK.
+
+ To install the Perl headers and the class CPerlBase documentation
+ so that you no more need the Perl sources around to compile Perl
+ applications using the SDK:
+
+ make sdkinstall
+
+ The destination directory is C:\Symbian\perl\X.Y.Z. For more
+ details, see F<symbian\PerlBase.pod>.
+
+ Once the headers have been installed, you can create a SIS for
+ the PerlApp:
+
+ make perlapp.sis
+
+ The perlapp.sis (11 kB -> 16 kB) will be built in the symbian
+ subdirectory, but a copy will also be made to the main directory.
+
+ If you want to package the Perl DLLs (one for WINS, one for ARMI),
+ the headers, and the documentation:
+
+ make perlsdk.zip
+
+ which will create perlXYZsdk.zip that can be used in another
+ Windows system with the SDK, without having to compile Perl in
+ that system.
+
+ If you want to package the PerlApp sources:
+
+ make perlapp.zip
+
+ If you want to package the perl.exe and miniperl.exe, you
+ can use the perlexe.sis and miniperlexe.sis make targets.
+ You also probably want the perllib.sis for the libraries
+ and maybe even the perlapp.sis for the recognizer.
+
+ The make target 'allsis' combines all the above SIS targets.
+
+ To clean up after compilation you can use either of
+
+ make clean
+ make distclean
+
+ depending on how clean you want to be.
+
+=head2 Compilation problems
+
+If you see right after "make" this
+
+ cat makefile.sh >makefile
+ 'cat' is not recognized as an internal or external command,
+ operable program or batch file.
+
+it means you need to (re)run the symbian\config.pl.
+
+If you get the error
+
+ 'perl' is not recognized as an internal or external command,
+ operable program or batch file.
+
+you may need to reinstall the ActivePerl.
+
+If you see this
+
+ ren makedef.pl nomakedef.pl
+ The system cannot find the file specified.
+ C:\Symbian\...\make.exe: [rename_makedef] Error 1 (ignored)
+
+please ignore it since it is nothing serious (the build process of
+renames the Perl makedef.pl as nomakedef.pl to avoid confusing it
+with a makedef.pl of the SDK).
+
+=head2 PerlApp
+
+The PerlApp application demonstrates how to embed Perl interpreters
+to a Symbian application. The "Time" menu item runs the following
+Perl code: C<print "Running in ", $^O, "\n", scalar localtime>,
+the "Oneliner" allows one to type in Perl code, and the "Run"
+opens a file chooser for selecting a Perl file to run.
+
+The PerlApp also is started when the "Perl recognizer" (also included
+and installed) detects a Perl file being activated througg the GUI,
+and offers either to install it under \Perl (if the Perl file is in
+the inbox of the messaging application) or to run it (if the Perl file
+is under \Perl).
+
+=head2 sisify.pl
+
+In the symbian subdirectory there is sisify.pl utility which can be
+used to package Perl scripts and/or Perl library directories into SIS
+files, which can be installed to the device. To run the sisify.pl
+utility, you will need to have the 'makesis' and 'uidcrc' utilities
+already installed. If you don't have the Win32 SDKs, you may try
+for example http://gnupoc.sourceforge.net/ or http://symbianos.org/~andreh/.
+
+=head2 Using Perl in Symbian
+
+First of all note that you have full access to the Symbian device
+when using Perl: you can do a lot of damage to your device (like
+removing system files) unless you are careful. Please do take
+backups before doing anything.
+
+The Perl port has been done for the most part using the Symbian
+standard POSIX-ish STDLIB library. It is a reasonably complete
+library, but certain corners of such emulation libraries that tend
+to be left unimplemented on non-UNIX platforms have been left
+unimplemented also this time: fork(), signals(), user/group ids,
+select() working for sockets, non-blocking sockets, and so forth.
+See the file symbian/config.sh and look for 'undef' to find the
+unsupported APIs (or from Perl use Config).
+
+The filesystem of Symbian devices uses DOSish syntax, "drives"
+separated from paths by a colon, and backslashes for the path. The
+exact assignment of the drives probably varies between platforms, but
+for example in Series 60 you might see C: as the (flash) main memory,
+D: as the RAM drive, E: as the memory card (MMC), Z: as the ROM. In
+Series 80 D: is the memory card. As far the devices go the NUL: is
+the bit bucket, the COMx: are the serial lines, IRCOMx: are the IR
+ports, TMP: might be C:\System\Temp. Remember to double those
+backslashes in doublequoted strings.
+
+The Perl DLL is installed in \System\Libs\. The Perl libraries and
+extension DLLs are installed in \System\Libs\Perl\X.Y.Z\. The PerlApp
+is installed in \System\Apps\, and the SIS also installs a couple of
+demo scripts in \Perl\ (C:\Mydocs\Perl\ on Nokia 7710).
+
+Note that the Symbian filesystem is very picky: it strongly prefers
+the \ instead of the /.
+
+When doing XS / Symbian C++ programming include first the Symbian
+headers, then any standard C/POSIX headers, then Perl headers, and finally
+any application headers.
+
+New() and Copy() are unfortunately used by both Symbian and Perl code
+so you'll have to play cpp games if you need them. PerlBase.h undefines
+the Perl definitions and redefines them as PerlNew() and PerlCopy().
+
+=head1 TO DO
+
+Lots. See F<symbian\TODO>.
+
+=head1 WARNING
+
+As of Perl Symbian port version 0.4.1 any part of Perl's standard
+regression test suite has not been run on a real Symbian device using
+the ported Perl, so innumerable bugs may lie in wait. Therefore there
+is absolutely no warranty.
+
+=head1 NOTE
+
+When creating and extending application programming interfaces (APIs)
+for Symbian or Series 60 or Series 80 or Series 90 it is suggested
+that trademarks, registered trademarks, or trade names are not used in
+the API names. Instead, developers should consider basing the API
+naming in the existing (C++, or maybe Java) public component and API
+naming, modified as appropriate by the rules of the programming
+language the new APIs are for.
+
+Nokia is a registered trademark of Nokia Corporation. Nokia's product
+names are trademarks or registered trademarks of Nokia. Other product
+and company names mentioned herein may be trademarks or trade names of
+their respective owners.
+
+=head1 AUTHOR
+
+Jarkko Hietaniemi
+
+=head1 COPYRIGHT
+
+Copyright (c) 2004-2005 Nokia. All rights reserved.
+
+Copyright (c) 2006-2007 Jarkko Hietaniemi.
+
+=head1 LICENSE
+
+The Symbian port is licensed under the same terms as Perl itself.
+
+=head1 HISTORY
+
+=over 4
+
+=item *
+
+0.1.0: April 2005
+
+(This will show as "0.01" in the Symbian Installer.)
+
+ - The console window is a very simple console indeed: one can
+ get the newline with "000" and the "C" button is a backspace.
+ Do not expect a terminal capable of vt100 or ANSI sequences.
+ The console is also "ASCII", you cannot input e.g. any accented
+ letters. Because of obvious physical constraints the console is
+ also very small: (in Nokia 6600) 22 columns, 17 rows.
+ - The following libraries are available:
+ AnyDBM_File AutoLoader base Carp Config Cwd constant
+ DynaLoader Exporter File::Spec integer lib strict Symbol
+ vars warnings XSLoader
+ - The following extensions are available:
+ attributes Compress::Zlib Cwd Data::Dumper Devel::Peek Digest::MD5 DynaLoader
+ Fcntl File::Glob Filter::Util::Call IO List::Util MIME::Base64
+ PerlIO::scalar PerlIO::via SDBM_File Socket Storable Time::HiRes
+ - The following extensions are missing for various technical reasons:
+ B ByteLoader Devel::DProf Devel::PPPort Encode GDBM_File
+ I18N::Langinfo IPC::SysV NDBM_File Opcode PerlIO::encoding POSIX
+ re Safe Sys::Hostname Sys::Syslog
+ threads threads::shared Unicode::Normalize
+ - Using MakeMaker or the Module::* to build and install modules
+ is not supported.
+ - Building XS other than the ones in the core is not supported.
+
+Since this is 0.something release, any future releases are almost
+guaranteed to be binary incompatible. As a sign of this the Symbian
+symbol exports are kept unfrozen and the .def files fully rebuilt
+every time.
+
+=item *
+
+0.2.0: October 2005
+
+ - Perl 5.9.3 (patch level 25741)
+ - Compress::Zlib and IO::Zlib supported
+ - sisify.pl added
+
+We maintain the binary incompatibility.
+
+=item *
+
+0.3.0: October 2005
+
+ - Perl 5.9.3 (patch level 25911)
+ - Series 80 2.0 and UIQ 2.1 support
+
+We maintain the binary incompatibility.
+
+=item *
+
+0.4.0: November 2005
+
+ - Perl 5.9.3 (patch level 26052)
+ - adding a sample Symbian extension
+
+We maintain the binary incompatibility.
+
+=item *
+
+0.4.1: December 2006
+
+ - Perl 5.9.5-to-be (patch level 30002)
+ - added extensions: Compress/Raw/Zlib, Digest/SHA,
+ Hash/Util, Math/BigInt/FastCalc, Text/Soundex, Time/Piece
+ - port to S90 1.1 by alexander smishlajev
+
+We maintain the binary incompatibility.
+
+=item *
+
+0.4.2: March 2007
+
+ - catchup with Perl 5.9.5-to-be (patch level 30812)
+ - tested to build with Microsoft Visual C++ 2005 Express Edition
+ (which uses Microsoft Visual C 8, instead of the old VC6),
+ SDK used for testing S60_2nd_FP3 aka 8.1a
+
+We maintain the binary incompatibility.
+
+=back
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlsyn.pod b/Master/tlpkg/tlperl/lib/pods/perlsyn.pod
new file mode 100644
index 00000000000..6359df4e141
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlsyn.pod
@@ -0,0 +1,934 @@
+=head1 NAME
+X<syntax>
+
+perlsyn - Perl syntax
+
+=head1 DESCRIPTION
+
+A Perl program consists of a sequence of declarations and statements
+which run from the top to the bottom. Loops, subroutines and other
+control structures allow you to jump around within the code.
+
+Perl is a B<free-form> language, you can format and indent it however
+you like. Whitespace mostly serves to separate tokens, unlike
+languages like Python where it is an important part of the syntax.
+
+Many of Perl's syntactic elements are B<optional>. Rather than
+requiring you to put parentheses around every function call and
+declare every variable, you can often leave such explicit elements off
+and Perl will figure out what you meant. This is known as B<Do What I
+Mean>, abbreviated B<DWIM>. It allows programmers to be B<lazy> and to
+code in a style with which they are comfortable.
+
+Perl B<borrows syntax> and concepts from many languages: awk, sed, C,
+Bourne Shell, Smalltalk, Lisp and even English. Other
+languages have borrowed syntax from Perl, particularly its regular
+expression extensions. So if you have programmed in another language
+you will see familiar pieces in Perl. They often work the same, but
+see L<perltrap> for information about how they differ.
+
+=head2 Declarations
+X<declaration> X<undef> X<undefined> X<uninitialized>
+
+The only things you need to declare in Perl are report formats and
+subroutines (and sometimes not even subroutines). A variable holds
+the undefined value (C<undef>) until it has been assigned a defined
+value, which is anything other than C<undef>. When used as a number,
+C<undef> is treated as C<0>; when used as a string, it is treated as
+the empty string, C<"">; and when used as a reference that isn't being
+assigned to, it is treated as an error. If you enable warnings,
+you'll be notified of an uninitialized value whenever you treat
+C<undef> as a string or a number. Well, usually. Boolean contexts,
+such as:
+
+ my $a;
+ if ($a) {}
+
+are exempt from warnings (because they care about truth rather than
+definedness). Operators such as C<++>, C<-->, C<+=>,
+C<-=>, and C<.=>, that operate on undefined left values such as:
+
+ my $a;
+ $a++;
+
+are also always exempt from such warnings.
+
+A declaration can be put anywhere a statement can, but has no effect on
+the execution of the primary sequence of statements--declarations all
+take effect at compile time. Typically all the declarations are put at
+the beginning or the end of the script. However, if you're using
+lexically-scoped private variables created with C<my()>, you'll
+have to make sure
+your format or subroutine definition is within the same block scope
+as the my if you expect to be able to access those private variables.
+
+Declaring a subroutine allows a subroutine name to be used as if it were a
+list operator from that point forward in the program. You can declare a
+subroutine without defining it by saying C<sub name>, thus:
+X<subroutine, declaration>
+
+ sub myname;
+ $me = myname $0 or die "can't get myname";
+
+Note that myname() functions as a list operator, not as a unary operator;
+so be careful to use C<or> instead of C<||> in this case. However, if
+you were to declare the subroutine as C<sub myname ($)>, then
+C<myname> would function as a unary operator, so either C<or> or
+C<||> would work.
+
+Subroutines declarations can also be loaded up with the C<require> statement
+or both loaded and imported into your namespace with a C<use> statement.
+See L<perlmod> for details on this.
+
+A statement sequence may contain declarations of lexically-scoped
+variables, but apart from declaring a variable name, the declaration acts
+like an ordinary statement, and is elaborated within the sequence of
+statements as if it were an ordinary statement. That means it actually
+has both compile-time and run-time effects.
+
+=head2 Comments
+X<comment> X<#>
+
+Text from a C<"#"> character until the end of the line is a comment,
+and is ignored. Exceptions include C<"#"> inside a string or regular
+expression.
+
+=head2 Simple Statements
+X<statement> X<semicolon> X<expression> X<;>
+
+The only kind of simple statement is an expression evaluated for its
+side effects. Every simple statement must be terminated with a
+semicolon, unless it is the final statement in a block, in which case
+the semicolon is optional. (A semicolon is still encouraged if the
+block takes up more than one line, because you may eventually add
+another line.) Note that there are some operators like C<eval {}> and
+C<do {}> that look like compound statements, but aren't (they're just
+TERMs in an expression), and thus need an explicit termination if used
+as the last item in a statement.
+
+=head2 Truth and Falsehood
+X<truth> X<falsehood> X<true> X<false> X<!> X<not> X<negation> X<0>
+
+The number 0, the strings C<'0'> and C<''>, the empty list C<()>, and
+C<undef> are all false in a boolean context. All other values are true.
+Negation of a true value by C<!> or C<not> returns a special false value.
+When evaluated as a string it is treated as C<''>, but as a number, it
+is treated as 0.
+
+=head2 Statement Modifiers
+X<statement modifier> X<modifier> X<if> X<unless> X<while>
+X<until> X<when> X<foreach> X<for>
+
+Any simple statement may optionally be followed by a I<SINGLE> modifier,
+just before the terminating semicolon (or block ending). The possible
+modifiers are:
+
+ if EXPR
+ unless EXPR
+ while EXPR
+ until EXPR
+ when EXPR
+ for LIST
+ foreach LIST
+
+The C<EXPR> following the modifier is referred to as the "condition".
+Its truth or falsehood determines how the modifier will behave.
+
+C<if> executes the statement once I<if> and only if the condition is
+true. C<unless> is the opposite, it executes the statement I<unless>
+the condition is true (i.e., if the condition is false).
+
+ print "Basset hounds got long ears" if length $ear >= 10;
+ go_outside() and play() unless $is_raining;
+
+C<when> executes the statement I<when> C<$_> smart matches C<EXPR>, and
+then either C<break>s out if it's enclosed in a C<given> scope or skips
+to the C<next> element when it lies directly inside a C<for> loop.
+See also L</"Switch statements">.
+
+ given ($something) {
+ $abc = 1 when /^abc/;
+ $just_a = 1 when /^a/;
+ $other = 1;
+ }
+
+ for (@names) {
+ admin($_) when [ qw/Alice Bob/ ];
+ regular($_) when [ qw/Chris David Ellen/ ];
+ }
+
+The C<foreach> modifier is an iterator: it executes the statement once
+for each item in the LIST (with C<$_> aliased to each item in turn).
+
+ print "Hello $_!\n" foreach qw(world Dolly nurse);
+
+C<while> repeats the statement I<while> the condition is true.
+C<until> does the opposite, it repeats the statement I<until> the
+condition is true (or while the condition is false):
+
+ # Both of these count from 0 to 10.
+ print $i++ while $i <= 10;
+ print $j++ until $j > 10;
+
+The C<while> and C<until> modifiers have the usual "C<while> loop"
+semantics (conditional evaluated first), except when applied to a
+C<do>-BLOCK (or to the deprecated C<do>-SUBROUTINE statement), in
+which case the block executes once before the conditional is
+evaluated. This is so that you can write loops like:
+
+ do {
+ $line = <STDIN>;
+ ...
+ } until $line eq ".\n";
+
+See L<perlfunc/do>. Note also that the loop control statements described
+later will I<NOT> work in this construct, because modifiers don't take
+loop labels. Sorry. You can always put another block inside of it
+(for C<next>) or around it (for C<last>) to do that sort of thing.
+For C<next>, just double the braces:
+X<next> X<last> X<redo>
+
+ do {{
+ next if $x == $y;
+ # do something here
+ }} until $x++ > $z;
+
+For C<last>, you have to be more elaborate:
+X<last>
+
+ LOOP: {
+ do {
+ last if $x = $y**2;
+ # do something here
+ } while $x++ <= $z;
+ }
+
+B<NOTE:> The behaviour of a C<my> statement modified with a statement
+modifier conditional or loop construct (e.g. C<my $x if ...>) is
+B<undefined>. The value of the C<my> variable may be C<undef>, any
+previously assigned value, or possibly anything else. Don't rely on
+it. Future versions of perl might do something different from the
+version of perl you try it out on. Here be dragons.
+X<my>
+
+=head2 Compound Statements
+X<statement, compound> X<block> X<bracket, curly> X<curly bracket> X<brace>
+X<{> X<}> X<if> X<unless> X<while> X<until> X<foreach> X<for> X<continue>
+
+In Perl, a sequence of statements that defines a scope is called a block.
+Sometimes a block is delimited by the file containing it (in the case
+of a required file, or the program as a whole), and sometimes a block
+is delimited by the extent of a string (in the case of an eval).
+
+But generally, a block is delimited by curly brackets, also known as braces.
+We will call this syntactic construct a BLOCK.
+
+The following compound statements may be used to control flow:
+
+ if (EXPR) BLOCK
+ if (EXPR) BLOCK else BLOCK
+ if (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
+ unless (EXPR) BLOCK
+ unless (EXPR) BLOCK else BLOCK
+ unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
+ LABEL while (EXPR) BLOCK
+ LABEL while (EXPR) BLOCK continue BLOCK
+ LABEL until (EXPR) BLOCK
+ LABEL until (EXPR) BLOCK continue BLOCK
+ LABEL for (EXPR; EXPR; EXPR) BLOCK
+ LABEL foreach VAR (LIST) BLOCK
+ LABEL foreach VAR (LIST) BLOCK continue BLOCK
+ LABEL BLOCK continue BLOCK
+
+Note that, unlike C and Pascal, these are defined in terms of BLOCKs,
+not statements. This means that the curly brackets are I<required>--no
+dangling statements allowed. If you want to write conditionals without
+curly brackets there are several other ways to do it. The following
+all do the same thing:
+
+ if (!open(FOO)) { die "Can't open $FOO: $!"; }
+ die "Can't open $FOO: $!" unless open(FOO);
+ open(FOO) or die "Can't open $FOO: $!"; # FOO or bust!
+ open(FOO) ? 'hi mom' : die "Can't open $FOO: $!";
+ # a bit exotic, that last one
+
+The C<if> statement is straightforward. Because BLOCKs are always
+bounded by curly brackets, there is never any ambiguity about which
+C<if> an C<else> goes with. If you use C<unless> in place of C<if>,
+the sense of the test is reversed. Like C<if>, C<unless> can be followed
+by C<else>. C<unless> can even be followed by one or more C<elsif>
+statements, though you may want to think twice before using that particular
+language construct, as everyone reading your code will have to think at least
+twice before they can understand what's going on.
+
+The C<while> statement executes the block as long as the expression is
+L<true|/"Truth and Falsehood">.
+The C<until> statement executes the block as long as the expression is
+false.
+The LABEL is optional, and if present, consists of an identifier followed
+by a colon. The LABEL identifies the loop for the loop control
+statements C<next>, C<last>, and C<redo>.
+If the LABEL is omitted, the loop control statement
+refers to the innermost enclosing loop. This may include dynamically
+looking back your call-stack at run time to find the LABEL. Such
+desperate behavior triggers a warning if you use the C<use warnings>
+pragma or the B<-w> flag.
+
+If there is a C<continue> BLOCK, it is always executed just before the
+conditional is about to be evaluated again. Thus it can be used to
+increment a loop variable, even when the loop has been continued via
+the C<next> statement.
+
+Extension modules can also hook into the Perl parser to define new
+kinds of compound statement. These are introduced by a keyword which
+the extension recognises, and the syntax following the keyword is
+defined entirely by the extension. If you are an implementor, see
+L<perlapi/PL_keyword_plugin> for the mechanism. If you are using such
+a module, see the module's documentation for details of the syntax that
+it defines.
+
+=head2 Loop Control
+X<loop control> X<loop, control> X<next> X<last> X<redo> X<continue>
+
+The C<next> command starts the next iteration of the loop:
+
+ LINE: while (<STDIN>) {
+ next LINE if /^#/; # discard comments
+ ...
+ }
+
+The C<last> command immediately exits the loop in question. The
+C<continue> block, if any, is not executed:
+
+ LINE: while (<STDIN>) {
+ last LINE if /^$/; # exit when done with header
+ ...
+ }
+
+The C<redo> command restarts the loop block without evaluating the
+conditional again. The C<continue> block, if any, is I<not> executed.
+This command is normally used by programs that want to lie to themselves
+about what was just input.
+
+For example, when processing a file like F</etc/termcap>.
+If your input lines might end in backslashes to indicate continuation, you
+want to skip ahead and get the next record.
+
+ while (<>) {
+ chomp;
+ if (s/\\$//) {
+ $_ .= <>;
+ redo unless eof();
+ }
+ # now process $_
+ }
+
+which is Perl short-hand for the more explicitly written version:
+
+ LINE: while (defined($line = <ARGV>)) {
+ chomp($line);
+ if ($line =~ s/\\$//) {
+ $line .= <ARGV>;
+ redo LINE unless eof(); # not eof(ARGV)!
+ }
+ # now process $line
+ }
+
+Note that if there were a C<continue> block on the above code, it would
+get executed only on lines discarded by the regex (since redo skips the
+continue block). A continue block is often used to reset line counters
+or C<?pat?> one-time matches:
+
+ # inspired by :1,$g/fred/s//WILMA/
+ while (<>) {
+ ?(fred)? && s//WILMA $1 WILMA/;
+ ?(barney)? && s//BETTY $1 BETTY/;
+ ?(homer)? && s//MARGE $1 MARGE/;
+ } continue {
+ print "$ARGV $.: $_";
+ close ARGV if eof(); # reset $.
+ reset if eof(); # reset ?pat?
+ }
+
+If the word C<while> is replaced by the word C<until>, the sense of the
+test is reversed, but the conditional is still tested before the first
+iteration.
+
+The loop control statements don't work in an C<if> or C<unless>, since
+they aren't loops. You can double the braces to make them such, though.
+
+ if (/pattern/) {{
+ last if /fred/;
+ next if /barney/; # same effect as "last", but doesn't document as well
+ # do something here
+ }}
+
+This is caused by the fact that a block by itself acts as a loop that
+executes once, see L<"Basic BLOCKs">.
+
+The form C<while/if BLOCK BLOCK>, available in Perl 4, is no longer
+available. Replace any occurrence of C<if BLOCK> by C<if (do BLOCK)>.
+
+=head2 For Loops
+X<for> X<foreach>
+
+Perl's C-style C<for> loop works like the corresponding C<while> loop;
+that means that this:
+
+ for ($i = 1; $i < 10; $i++) {
+ ...
+ }
+
+is the same as this:
+
+ $i = 1;
+ while ($i < 10) {
+ ...
+ } continue {
+ $i++;
+ }
+
+There is one minor difference: if variables are declared with C<my>
+in the initialization section of the C<for>, the lexical scope of
+those variables is exactly the C<for> loop (the body of the loop
+and the control sections).
+X<my>
+
+Besides the normal array index looping, C<for> can lend itself
+to many other interesting applications. Here's one that avoids the
+problem you get into if you explicitly test for end-of-file on
+an interactive file descriptor causing your program to appear to
+hang.
+X<eof> X<end-of-file> X<end of file>
+
+ $on_a_tty = -t STDIN && -t STDOUT;
+ sub prompt { print "yes? " if $on_a_tty }
+ for ( prompt(); <STDIN>; prompt() ) {
+ # do something
+ }
+
+Using C<readline> (or the operator form, C<< <EXPR> >>) as the
+conditional of a C<for> loop is shorthand for the following. This
+behaviour is the same as a C<while> loop conditional.
+X<readline> X<< <> >>
+
+ for ( prompt(); defined( $_ = <STDIN> ); prompt() ) {
+ # do something
+ }
+
+=head2 Foreach Loops
+X<for> X<foreach>
+
+The C<foreach> loop iterates over a normal list value and sets the
+variable VAR to be each element of the list in turn. If the variable
+is preceded with the keyword C<my>, then it is lexically scoped, and
+is therefore visible only within the loop. Otherwise, the variable is
+implicitly local to the loop and regains its former value upon exiting
+the loop. If the variable was previously declared with C<my>, it uses
+that variable instead of the global one, but it's still localized to
+the loop. This implicit localisation occurs I<only> in a C<foreach>
+loop.
+X<my> X<local>
+
+The C<foreach> keyword is actually a synonym for the C<for> keyword, so
+you can use C<foreach> for readability or C<for> for brevity. (Or because
+the Bourne shell is more familiar to you than I<csh>, so writing C<for>
+comes more naturally.) If VAR is omitted, C<$_> is set to each value.
+X<$_>
+
+If any element of LIST is an lvalue, you can modify it by modifying
+VAR inside the loop. Conversely, if any element of LIST is NOT an
+lvalue, any attempt to modify that element will fail. In other words,
+the C<foreach> loop index variable is an implicit alias for each item
+in the list that you're looping over.
+X<alias>
+
+If any part of LIST is an array, C<foreach> will get very confused if
+you add or remove elements within the loop body, for example with
+C<splice>. So don't do that.
+X<splice>
+
+C<foreach> probably won't do what you expect if VAR is a tied or other
+special variable. Don't do that either.
+
+Examples:
+
+ for (@ary) { s/foo/bar/ }
+
+ for my $elem (@elements) {
+ $elem *= 2;
+ }
+
+ for $count (10,9,8,7,6,5,4,3,2,1,'BOOM') {
+ print $count, "\n"; sleep(1);
+ }
+
+ for (1..15) { print "Merry Christmas\n"; }
+
+ foreach $item (split(/:[\\\n:]*/, $ENV{TERMCAP})) {
+ print "Item: $item\n";
+ }
+
+Here's how a C programmer might code up a particular algorithm in Perl:
+
+ for (my $i = 0; $i < @ary1; $i++) {
+ for (my $j = 0; $j < @ary2; $j++) {
+ if ($ary1[$i] > $ary2[$j]) {
+ last; # can't go to outer :-(
+ }
+ $ary1[$i] += $ary2[$j];
+ }
+ # this is where that last takes me
+ }
+
+Whereas here's how a Perl programmer more comfortable with the idiom might
+do it:
+
+ OUTER: for my $wid (@ary1) {
+ INNER: for my $jet (@ary2) {
+ next OUTER if $wid > $jet;
+ $wid += $jet;
+ }
+ }
+
+See how much easier this is? It's cleaner, safer, and faster. It's
+cleaner because it's less noisy. It's safer because if code gets added
+between the inner and outer loops later on, the new code won't be
+accidentally executed. The C<next> explicitly iterates the other loop
+rather than merely terminating the inner one. And it's faster because
+Perl executes a C<foreach> statement more rapidly than it would the
+equivalent C<for> loop.
+
+=head2 Basic BLOCKs
+X<block>
+
+A BLOCK by itself (labeled or not) is semantically equivalent to a
+loop that executes once. Thus you can use any of the loop control
+statements in it to leave or restart the block. (Note that this is
+I<NOT> true in C<eval{}>, C<sub{}>, or contrary to popular belief
+C<do{}> blocks, which do I<NOT> count as loops.) The C<continue>
+block is optional.
+
+The BLOCK construct can be used to emulate case structures.
+
+ SWITCH: {
+ if (/^abc/) { $abc = 1; last SWITCH; }
+ if (/^def/) { $def = 1; last SWITCH; }
+ if (/^xyz/) { $xyz = 1; last SWITCH; }
+ $nothing = 1;
+ }
+
+Such constructs are quite frequently used, because older versions
+of Perl had no official C<switch> statement.
+
+=head2 Switch statements
+X<switch> X<case> X<given> X<when> X<default>
+
+Starting from Perl 5.10, you can say
+
+ use feature "switch";
+
+which enables a switch feature that is closely based on the
+Perl 6 proposal.
+
+The keywords C<given> and C<when> are analogous
+to C<switch> and C<case> in other languages, so the code
+above could be written as
+
+ given($_) {
+ when (/^abc/) { $abc = 1; }
+ when (/^def/) { $def = 1; }
+ when (/^xyz/) { $xyz = 1; }
+ default { $nothing = 1; }
+ }
+
+This construct is very flexible and powerful. For example:
+
+ use feature ":5.10";
+ given($foo) {
+ when (undef) {
+ say '$foo is undefined';
+ }
+ when ("foo") {
+ say '$foo is the string "foo"';
+ }
+ when ([1,3,5,7,9]) {
+ say '$foo is an odd digit';
+ continue; # Fall through
+ }
+ when ($_ < 100) {
+ say '$foo is numerically less than 100';
+ }
+ when (\&complicated_check) {
+ say 'a complicated check for $foo is true';
+ }
+ default {
+ die q(I don't know what to do with $foo);
+ }
+ }
+
+C<given(EXPR)> will assign the value of EXPR to C<$_>
+within the lexical scope of the block, so it's similar to
+
+ do { my $_ = EXPR; ... }
+
+except that the block is automatically broken out of by a
+successful C<when> or an explicit C<break>.
+
+Most of the power comes from implicit smart matching:
+
+ when($foo)
+
+is exactly equivalent to
+
+ when($_ ~~ $foo)
+
+Most of the time, C<when(EXPR)> is treated as an implicit smart match of
+C<$_>, i.e. C<$_ ~~ EXPR>. (See L</"Smart matching in detail"> for more
+information on smart matching.) But when EXPR is one of the below
+exceptional cases, it is used directly as a boolean:
+
+=over 4
+
+=item *
+
+a subroutine or method call
+
+=item *
+
+a regular expression match, i.e. C</REGEX/> or C<$foo =~ /REGEX/>,
+or a negated regular expression match (C<!/REGEX/> or C<$foo !~ /REGEX/>).
+
+=item *
+
+a comparison such as C<$_ E<lt> 10> or C<$x eq "abc">
+(or of course C<$_ ~~ $c>)
+
+=item *
+
+C<defined(...)>, C<exists(...)>, or C<eof(...)>
+
+=item *
+
+a negated expression C<!(...)> or C<not (...)>, or a logical
+exclusive-or C<(...) xor (...)>.
+
+=item *
+
+a filetest operator, with the exception of C<-s>, C<-M>, C<-A>, and C<-C>,
+that return numerical values, not boolean ones.
+
+=item *
+
+the C<..> and C<...> flip-flop operators.
+
+=back
+
+In those cases the value of EXPR is used directly as a boolean.
+
+Furthermore:
+
+=over 4
+
+=item *
+
+If EXPR is C<... && ...> or C<... and ...>, the test
+is applied recursively to both arguments. If I<both>
+arguments pass the test, then the argument is treated
+as boolean.
+
+=item *
+
+If EXPR is C<... || ...>, C<... // ...> or C<... or ...>, the test
+is applied recursively to the first argument.
+
+=back
+
+These rules look complicated, but usually they will do what
+you want. For example you could write:
+
+ when (/^\d+$/ && $_ < 75) { ... }
+
+Another useful shortcut is that, if you use a literal array
+or hash as the argument to C<given>, it is turned into a
+reference. So C<given(@foo)> is the same as C<given(\@foo)>,
+for example.
+
+C<default> behaves exactly like C<when(1 == 1)>, which is
+to say that it always matches.
+
+=head3 Breaking out
+
+You can use the C<break> keyword to break out of the enclosing
+C<given> block. Every C<when> block is implicitly ended with
+a C<break>.
+
+=head3 Fall-through
+
+You can use the C<continue> keyword to fall through from one
+case to the next:
+
+ given($foo) {
+ when (/x/) { say '$foo contains an x'; continue }
+ when (/y/) { say '$foo contains a y' }
+ default { say '$foo does not contain a y' }
+ }
+
+=head3 Switching in a loop
+
+Instead of using C<given()>, you can use a C<foreach()> loop.
+For example, here's one way to count how many times a particular
+string occurs in an array:
+
+ my $count = 0;
+ for (@array) {
+ when ("foo") { ++$count }
+ }
+ print "\@array contains $count copies of 'foo'\n";
+
+At the end of all C<when> blocks, there is an implicit C<next>.
+You can override that with an explicit C<last> if you're only
+interested in the first match.
+
+This doesn't work if you explicitly specify a loop variable,
+as in C<for $item (@array)>. You have to use the default
+variable C<$_>. (You can use C<for my $_ (@array)>.)
+
+=head3 Smart matching in detail
+
+The behaviour of a smart match depends on what type of thing its arguments
+are. The behaviour is determined by the following table: the first row
+that applies determines the match behaviour (which is thus mostly
+determined by the type of the right operand). Note that the smart match
+implicitly dereferences any non-blessed hash or array ref, so the "Hash"
+and "Array" entries apply in those cases. (For blessed references, the
+"Object" entries apply.)
+
+Note that the "Matching Code" column is not always an exact rendition. For
+example, the smart match operator short-circuits whenever possible, but
+C<grep> does not.
+
+ $a $b Type of Match Implied Matching Code
+ ====== ===== ===================== =============
+ Any undef undefined !defined $a
+
+ Any Object invokes ~~ overloading on $object, or dies
+
+ Hash CodeRef sub truth for each key[1] !grep { !$b->($_) } keys %$a
+ Array CodeRef sub truth for each elt[1] !grep { !$b->($_) } @$a
+ Any CodeRef scalar sub truth $b->($a)
+
+ Hash Hash hash keys identical (every key is found in both hashes)
+ Array Hash hash keys intersection grep { exists $b->{$_} } @$a
+ Regex Hash hash key grep grep /$a/, keys %$b
+ undef Hash always false (undef can't be a key)
+ Any Hash hash entry existence exists $b->{$a}
+
+ Hash Array hash keys intersection grep { exists $a->{$_} } @$b
+ Array Array arrays are comparable[2]
+ Regex Array array grep grep /$a/, @$b
+ undef Array array contains undef grep !defined, @$b
+ Any Array match against an array element[3]
+ grep $a ~~ $_, @$b
+
+ Hash Regex hash key grep grep /$b/, keys %$a
+ Array Regex array grep grep /$b/, @$a
+ Any Regex pattern match $a =~ /$b/
+
+ Object Any invokes ~~ overloading on $object, or falls back:
+ Any Num numeric equality $a == $b
+ Num numish[4] numeric equality $a == $b
+ undef Any undefined !defined($b)
+ Any Any string equality $a eq $b
+
+ 1 - empty hashes or arrays will match.
+ 2 - that is, each element smart-matches the element of same index in the
+ other array. [3]
+ 3 - If a circular reference is found, we fall back to referential equality.
+ 4 - either a real number, or a string that looks like a number
+
+=head3 Custom matching via overloading
+
+You can change the way that an object is matched by overloading
+the C<~~> operator. This may alter the usual smart match semantics.
+
+It should be noted that C<~~> will refuse to work on objects that
+don't overload it (in order to avoid relying on the object's
+underlying structure).
+
+Note also that smart match's matching rules take precedence over
+overloading, so if C<$obj> has smart match overloading, then
+
+ $obj ~~ X
+
+will not automatically invoke the overload method with X as an argument;
+instead the table above is consulted as normal, and based in the type of X,
+overloading may or may not be invoked.
+
+See L<overload>.
+
+=head3 Differences from Perl 6
+
+The Perl 5 smart match and C<given>/C<when> constructs are not
+absolutely identical to their Perl 6 analogues. The most visible
+difference is that, in Perl 5, parentheses are required around
+the argument to C<given()> and C<when()> (except when this last
+one is used as a statement modifier). Parentheses in Perl 6
+are always optional in a control construct such as C<if()>,
+C<while()>, or C<when()>; they can't be made optional in Perl
+5 without a great deal of potential confusion, because Perl 5
+would parse the expression
+
+ given $foo {
+ ...
+ }
+
+as though the argument to C<given> were an element of the hash
+C<%foo>, interpreting the braces as hash-element syntax.
+
+The table of smart matches is not identical to that proposed by the
+Perl 6 specification, mainly due to the differences between Perl 6's
+and Perl 5's data models.
+
+In Perl 6, C<when()> will always do an implicit smart match
+with its argument, whilst it is convenient in Perl 5 to
+suppress this implicit smart match in certain situations,
+as documented above. (The difference is largely because Perl 5
+does not, even internally, have a boolean type.)
+
+=head2 Goto
+X<goto>
+
+Although not for the faint of heart, Perl does support a C<goto>
+statement. There are three forms: C<goto>-LABEL, C<goto>-EXPR, and
+C<goto>-&NAME. A loop's LABEL is not actually a valid target for
+a C<goto>; it's just the name of the loop.
+
+The C<goto>-LABEL form finds the statement labeled with LABEL and resumes
+execution there. It may not be used to go into any construct that
+requires initialization, such as a subroutine or a C<foreach> loop. It
+also can't be used to go into a construct that is optimized away. It
+can be used to go almost anywhere else within the dynamic scope,
+including out of subroutines, but it's usually better to use some other
+construct such as C<last> or C<die>. The author of Perl has never felt the
+need to use this form of C<goto> (in Perl, that is--C is another matter).
+
+The C<goto>-EXPR form expects a label name, whose scope will be resolved
+dynamically. This allows for computed C<goto>s per FORTRAN, but isn't
+necessarily recommended if you're optimizing for maintainability:
+
+ goto(("FOO", "BAR", "GLARCH")[$i]);
+
+The C<goto>-&NAME form is highly magical, and substitutes a call to the
+named subroutine for the currently running subroutine. This is used by
+C<AUTOLOAD()> subroutines that wish to load another subroutine and then
+pretend that the other subroutine had been called in the first place
+(except that any modifications to C<@_> in the current subroutine are
+propagated to the other subroutine.) After the C<goto>, not even C<caller()>
+will be able to tell that this routine was called first.
+
+In almost all cases like this, it's usually a far, far better idea to use the
+structured control flow mechanisms of C<next>, C<last>, or C<redo> instead of
+resorting to a C<goto>. For certain applications, the catch and throw pair of
+C<eval{}> and die() for exception processing can also be a prudent approach.
+
+=head2 PODs: Embedded Documentation
+X<POD> X<documentation>
+
+Perl has a mechanism for intermixing documentation with source code.
+While it's expecting the beginning of a new statement, if the compiler
+encounters a line that begins with an equal sign and a word, like this
+
+ =head1 Here There Be Pods!
+
+Then that text and all remaining text up through and including a line
+beginning with C<=cut> will be ignored. The format of the intervening
+text is described in L<perlpod>.
+
+This allows you to intermix your source code
+and your documentation text freely, as in
+
+ =item snazzle($)
+
+ The snazzle() function will behave in the most spectacular
+ form that you can possibly imagine, not even excepting
+ cybernetic pyrotechnics.
+
+ =cut back to the compiler, nuff of this pod stuff!
+
+ sub snazzle($) {
+ my $thingie = shift;
+ .........
+ }
+
+Note that pod translators should look at only paragraphs beginning
+with a pod directive (it makes parsing easier), whereas the compiler
+actually knows to look for pod escapes even in the middle of a
+paragraph. This means that the following secret stuff will be
+ignored by both the compiler and the translators.
+
+ $a=3;
+ =secret stuff
+ warn "Neither POD nor CODE!?"
+ =cut back
+ print "got $a\n";
+
+You probably shouldn't rely upon the C<warn()> being podded out forever.
+Not all pod translators are well-behaved in this regard, and perhaps
+the compiler will become pickier.
+
+One may also use pod directives to quickly comment out a section
+of code.
+
+=head2 Plain Old Comments (Not!)
+X<comment> X<line> X<#> X<preprocessor> X<eval>
+
+Perl can process line directives, much like the C preprocessor. Using
+this, one can control Perl's idea of filenames and line numbers in
+error or warning messages (especially for strings that are processed
+with C<eval()>). The syntax for this mechanism is the same as for most
+C preprocessors: it matches the regular expression
+
+ # example: '# line 42 "new_filename.plx"'
+ /^\# \s*
+ line \s+ (\d+) \s*
+ (?:\s("?)([^"]+)\2)? \s*
+ $/x
+
+with C<$1> being the line number for the next line, and C<$3> being
+the optional filename (specified with or without quotes).
+
+There is a fairly obvious gotcha included with the line directive:
+Debuggers and profilers will only show the last source line to appear
+at a particular line number in a given file. Care should be taken not
+to cause line number collisions in code you'd like to debug later.
+
+Here are some examples that you should be able to type into your command
+shell:
+
+ % perl
+ # line 200 "bzzzt"
+ # the `#' on the previous line must be the first char on line
+ die 'foo';
+ __END__
+ foo at bzzzt line 201.
+
+ % perl
+ # line 200 "bzzzt"
+ eval qq[\n#line 2001 ""\ndie 'foo']; print $@;
+ __END__
+ foo at - line 2001.
+
+ % perl
+ eval qq[\n#line 200 "foo bar"\ndie 'foo']; print $@;
+ __END__
+ foo at foo bar line 200.
+
+ % perl
+ # line 345 "goop"
+ eval "\n#line " . __LINE__ . ' "' . __FILE__ ."\"\ndie 'foo'";
+ print $@;
+ __END__
+ foo at goop line 345.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlthrtut.pod b/Master/tlpkg/tlperl/lib/pods/perlthrtut.pod
new file mode 100644
index 00000000000..18a6f46daa2
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlthrtut.pod
@@ -0,0 +1,1176 @@
+=head1 NAME
+
+perlthrtut - Tutorial on threads in Perl
+
+=head1 DESCRIPTION
+
+This tutorial describes the use of Perl interpreter threads (sometimes
+referred to as I<ithreads>) that was first introduced in Perl 5.6.0. In this
+model, each thread runs in its own Perl interpreter, and any data sharing
+between threads must be explicit. The user-level interface for I<ithreads>
+uses the L<threads> class.
+
+B<NOTE>: There was another older Perl threading flavor called the 5.005 model
+that used the L<Threads> class. This old model was known to have problems, is
+deprecated, and was removed for release 5.10. You are
+strongly encouraged to migrate any existing 5.005 threads code to the new
+model as soon as possible.
+
+You can see which (or neither) threading flavour you have by
+running C<perl -V> and looking at the C<Platform> section.
+If you have C<useithreads=define> you have ithreads, if you
+have C<use5005threads=define> you have 5.005 threads.
+If you have neither, you don't have any thread support built in.
+If you have both, you are in trouble.
+
+The L<threads> and L<threads::shared> modules are included in the core Perl
+distribution. Additionally, they are maintained as a separate modules on
+CPAN, so you can check there for any updates.
+
+=head1 What Is A Thread Anyway?
+
+A thread is a flow of control through a program with a single
+execution point.
+
+Sounds an awful lot like a process, doesn't it? Well, it should.
+Threads are one of the pieces of a process. Every process has at least
+one thread and, up until now, every process running Perl had only one
+thread. With 5.8, though, you can create extra threads. We're going
+to show you how, when, and why.
+
+=head1 Threaded Program Models
+
+There are three basic ways that you can structure a threaded
+program. Which model you choose depends on what you need your program
+to do. For many non-trivial threaded programs, you'll need to choose
+different models for different pieces of your program.
+
+=head2 Boss/Worker
+
+The boss/worker model usually has one I<boss> thread and one or more
+I<worker> threads. The boss thread gathers or generates tasks that need
+to be done, then parcels those tasks out to the appropriate worker
+thread.
+
+This model is common in GUI and server programs, where a main thread
+waits for some event and then passes that event to the appropriate
+worker threads for processing. Once the event has been passed on, the
+boss thread goes back to waiting for another event.
+
+The boss thread does relatively little work. While tasks aren't
+necessarily performed faster than with any other method, it tends to
+have the best user-response times.
+
+=head2 Work Crew
+
+In the work crew model, several threads are created that do
+essentially the same thing to different pieces of data. It closely
+mirrors classical parallel processing and vector processors, where a
+large array of processors do the exact same thing to many pieces of
+data.
+
+This model is particularly useful if the system running the program
+will distribute multiple threads across different processors. It can
+also be useful in ray tracing or rendering engines, where the
+individual threads can pass on interim results to give the user visual
+feedback.
+
+=head2 Pipeline
+
+The pipeline model divides up a task into a series of steps, and
+passes the results of one step on to the thread processing the
+next. Each thread does one thing to each piece of data and passes the
+results to the next thread in line.
+
+This model makes the most sense if you have multiple processors so two
+or more threads will be executing in parallel, though it can often
+make sense in other contexts as well. It tends to keep the individual
+tasks small and simple, as well as allowing some parts of the pipeline
+to block (on I/O or system calls, for example) while other parts keep
+going. If you're running different parts of the pipeline on different
+processors you may also take advantage of the caches on each
+processor.
+
+This model is also handy for a form of recursive programming where,
+rather than having a subroutine call itself, it instead creates
+another thread. Prime and Fibonacci generators both map well to this
+form of the pipeline model. (A version of a prime number generator is
+presented later on.)
+
+=head1 What kind of threads are Perl threads?
+
+If you have experience with other thread implementations, you might
+find that things aren't quite what you expect. It's very important to
+remember when dealing with Perl threads that I<Perl Threads Are Not X
+Threads> for all values of X. They aren't POSIX threads, or
+DecThreads, or Java's Green threads, or Win32 threads. There are
+similarities, and the broad concepts are the same, but if you start
+looking for implementation details you're going to be either
+disappointed or confused. Possibly both.
+
+This is not to say that Perl threads are completely different from
+everything that's ever come before. They're not. Perl's threading
+model owes a lot to other thread models, especially POSIX. Just as
+Perl is not C, though, Perl threads are not POSIX threads. So if you
+find yourself looking for mutexes, or thread priorities, it's time to
+step back a bit and think about what you want to do and how Perl can
+do it.
+
+However, it is important to remember that Perl threads cannot magically
+do things unless your operating system's threads allow it. So if your
+system blocks the entire process on C<sleep()>, Perl usually will, as well.
+
+B<Perl Threads Are Different.>
+
+=head1 Thread-Safe Modules
+
+The addition of threads has changed Perl's internals
+substantially. There are implications for people who write
+modules with XS code or external libraries. However, since Perl data is
+not shared among threads by default, Perl modules stand a high chance of
+being thread-safe or can be made thread-safe easily. Modules that are not
+tagged as thread-safe should be tested or code reviewed before being used
+in production code.
+
+Not all modules that you might use are thread-safe, and you should
+always assume a module is unsafe unless the documentation says
+otherwise. This includes modules that are distributed as part of the
+core. Threads are a relatively new feature, and even some of the standard
+modules aren't thread-safe.
+
+Even if a module is thread-safe, it doesn't mean that the module is optimized
+to work well with threads. A module could possibly be rewritten to utilize
+the new features in threaded Perl to increase performance in a threaded
+environment.
+
+If you're using a module that's not thread-safe for some reason, you
+can protect yourself by using it from one, and only one thread at all.
+If you need multiple threads to access such a module, you can use semaphores and
+lots of programming discipline to control access to it. Semaphores
+are covered in L</"Basic semaphores">.
+
+See also L</"Thread-Safety of System Libraries">.
+
+=head1 Thread Basics
+
+The L<threads> module provides the basic functions you need to write
+threaded programs. In the following sections, we'll cover the basics,
+showing you what you need to do to create a threaded program. After
+that, we'll go over some of the features of the L<threads> module that
+make threaded programming easier.
+
+=head2 Basic Thread Support
+
+Thread support is a Perl compile-time option. It's something that's
+turned on or off when Perl is built at your site, rather than when
+your programs are compiled. If your Perl wasn't compiled with thread
+support enabled, then any attempt to use threads will fail.
+
+Your programs can use the Config module to check whether threads are
+enabled. If your program can't run without them, you can say something
+like:
+
+ use Config;
+ $Config{useithreads} or die('Recompile Perl with threads to run this program.');
+
+A possibly-threaded program using a possibly-threaded module might
+have code like this:
+
+ use Config;
+ use MyMod;
+
+ BEGIN {
+ if ($Config{useithreads}) {
+ # We have threads
+ require MyMod_threaded;
+ import MyMod_threaded;
+ } else {
+ require MyMod_unthreaded;
+ import MyMod_unthreaded;
+ }
+ }
+
+Since code that runs both with and without threads is usually pretty
+messy, it's best to isolate the thread-specific code in its own
+module. In our example above, that's what C<MyMod_threaded> is, and it's
+only imported if we're running on a threaded Perl.
+
+=head2 A Note about the Examples
+
+In a real situation, care should be taken that all threads are finished
+executing before the program exits. That care has B<not> been taken in these
+examples in the interest of simplicity. Running these examples I<as is> will
+produce error messages, usually caused by the fact that there are still
+threads running when the program exits. You should not be alarmed by this.
+
+=head2 Creating Threads
+
+The L<threads> module provides the tools you need to create new
+threads. Like any other module, you need to tell Perl that you want to use
+it; C<use threads;> imports all the pieces you need to create basic
+threads.
+
+The simplest, most straightforward way to create a thread is with C<create()>:
+
+ use threads;
+
+ my $thr = threads->create(\&sub1);
+
+ sub sub1 {
+ print("In the thread\n");
+ }
+
+The C<create()> method takes a reference to a subroutine and creates a new
+thread that starts executing in the referenced subroutine. Control
+then passes both to the subroutine and the caller.
+
+If you need to, your program can pass parameters to the subroutine as
+part of the thread startup. Just include the list of parameters as
+part of the C<threads-E<gt>create()> call, like this:
+
+ use threads;
+
+ my $Param3 = 'foo';
+ my $thr1 = threads->create(\&sub1, 'Param 1', 'Param 2', $Param3);
+ my @ParamList = (42, 'Hello', 3.14);
+ my $thr2 = threads->create(\&sub1, @ParamList);
+ my $thr3 = threads->create(\&sub1, qw(Param1 Param2 Param3));
+
+ sub sub1 {
+ my @InboundParameters = @_;
+ print("In the thread\n");
+ print('Got parameters >', join('<>', @InboundParameters), "<\n");
+ }
+
+The last example illustrates another feature of threads. You can spawn
+off several threads using the same subroutine. Each thread executes
+the same subroutine, but in a separate thread with a separate
+environment and potentially separate arguments.
+
+C<new()> is a synonym for C<create()>.
+
+=head2 Waiting For A Thread To Exit
+
+Since threads are also subroutines, they can return values. To wait
+for a thread to exit and extract any values it might return, you can
+use the C<join()> method:
+
+ use threads;
+
+ my ($thr) = threads->create(\&sub1);
+
+ my @ReturnData = $thr->join();
+ print('Thread returned ', join(', ', @ReturnData), "\n");
+
+ sub sub1 { return ('Fifty-six', 'foo', 2); }
+
+In the example above, the C<join()> method returns as soon as the thread
+ends. In addition to waiting for a thread to finish and gathering up
+any values that the thread might have returned, C<join()> also performs
+any OS cleanup necessary for the thread. That cleanup might be
+important, especially for long-running programs that spawn lots of
+threads. If you don't want the return values and don't want to wait
+for the thread to finish, you should call the C<detach()> method
+instead, as described next.
+
+NOTE: In the example above, the thread returns a list, thus necessitating
+that the thread creation call be made in list context (i.e., C<my ($thr)>).
+See L<< threads/"$thr->join()" >> and L<threads/"THREAD CONTEXT"> for more
+details on thread context and return values.
+
+=head2 Ignoring A Thread
+
+C<join()> does three things: it waits for a thread to exit, cleans up
+after it, and returns any data the thread may have produced. But what
+if you're not interested in the thread's return values, and you don't
+really care when the thread finishes? All you want is for the thread
+to get cleaned up after when it's done.
+
+In this case, you use the C<detach()> method. Once a thread is detached,
+it'll run until it's finished; then Perl will clean up after it
+automatically.
+
+ use threads;
+
+ my $thr = threads->create(\&sub1); # Spawn the thread
+
+ $thr->detach(); # Now we officially don't care any more
+
+ sleep(15); # Let thread run for awhile
+
+ sub sub1 {
+ $a = 0;
+ while (1) {
+ $a++;
+ print("\$a is $a\n");
+ sleep(1);
+ }
+ }
+
+Once a thread is detached, it may not be joined, and any return data
+that it might have produced (if it was done and waiting for a join) is
+lost.
+
+C<detach()> can also be called as a class method to allow a thread to
+detach itself:
+
+ use threads;
+
+ my $thr = threads->create(\&sub1);
+
+ sub sub1 {
+ threads->detach();
+ # Do more work
+ }
+
+=head2 Process and Thread Termination
+
+With threads one must be careful to make sure they all have a chance to
+run to completion, assuming that is what you want.
+
+An action that terminates a process will terminate I<all> running
+threads. die() and exit() have this property,
+and perl does an exit when the main thread exits,
+perhaps implicitly by falling off the end of your code,
+even if that's not what you want.
+
+As an example of this case, this code prints the message
+"Perl exited with active threads: 2 running and unjoined":
+
+ use threads;
+ my $thr1 = threads->new(\&thrsub, "test1");
+ my $thr2 = threads->new(\&thrsub, "test2");
+ sub thrsub {
+ my ($message) = @_;
+ sleep 1;
+ print "thread $message\n";
+ }
+
+But when the following lines are added at the end:
+
+ $thr1->join();
+ $thr2->join();
+
+it prints two lines of output, a perhaps more useful outcome.
+
+=head1 Threads And Data
+
+Now that we've covered the basics of threads, it's time for our next
+topic: Data. Threading introduces a couple of complications to data
+access that non-threaded programs never need to worry about.
+
+=head2 Shared And Unshared Data
+
+The biggest difference between Perl I<ithreads> and the old 5.005 style
+threading, or for that matter, to most other threading systems out there,
+is that by default, no data is shared. When a new Perl thread is created,
+all the data associated with the current thread is copied to the new
+thread, and is subsequently private to that new thread!
+This is similar in feel to what happens when a Unix process forks,
+except that in this case, the data is just copied to a different part of
+memory within the same process rather than a real fork taking place.
+
+To make use of threading, however, one usually wants the threads to share
+at least some data between themselves. This is done with the
+L<threads::shared> module and the C<:shared> attribute:
+
+ use threads;
+ use threads::shared;
+
+ my $foo :shared = 1;
+ my $bar = 1;
+ threads->create(sub { $foo++; $bar++; })->join();
+
+ print("$foo\n"); # Prints 2 since $foo is shared
+ print("$bar\n"); # Prints 1 since $bar is not shared
+
+In the case of a shared array, all the array's elements are shared, and for
+a shared hash, all the keys and values are shared. This places
+restrictions on what may be assigned to shared array and hash elements: only
+simple values or references to shared variables are allowed - this is
+so that a private variable can't accidentally become shared. A bad
+assignment will cause the thread to die. For example:
+
+ use threads;
+ use threads::shared;
+
+ my $var = 1;
+ my $svar :shared = 2;
+ my %hash :shared;
+
+ ... create some threads ...
+
+ $hash{a} = 1; # All threads see exists($hash{a}) and $hash{a} == 1
+ $hash{a} = $var; # okay - copy-by-value: same effect as previous
+ $hash{a} = $svar; # okay - copy-by-value: same effect as previous
+ $hash{a} = \$svar; # okay - a reference to a shared variable
+ $hash{a} = \$var; # This will die
+ delete($hash{a}); # okay - all threads will see !exists($hash{a})
+
+Note that a shared variable guarantees that if two or more threads try to
+modify it at the same time, the internal state of the variable will not
+become corrupted. However, there are no guarantees beyond this, as
+explained in the next section.
+
+=head2 Thread Pitfalls: Races
+
+While threads bring a new set of useful tools, they also bring a
+number of pitfalls. One pitfall is the race condition:
+
+ use threads;
+ use threads::shared;
+
+ my $a :shared = 1;
+ my $thr1 = threads->create(\&sub1);
+ my $thr2 = threads->create(\&sub2);
+
+ $thr1->join();
+ $thr2->join();
+ print("$a\n");
+
+ sub sub1 { my $foo = $a; $a = $foo + 1; }
+ sub sub2 { my $bar = $a; $a = $bar + 1; }
+
+What do you think C<$a> will be? The answer, unfortunately, is I<it
+depends>. Both C<sub1()> and C<sub2()> access the global variable C<$a>, once
+to read and once to write. Depending on factors ranging from your
+thread implementation's scheduling algorithm to the phase of the moon,
+C<$a> can be 2 or 3.
+
+Race conditions are caused by unsynchronized access to shared
+data. Without explicit synchronization, there's no way to be sure that
+nothing has happened to the shared data between the time you access it
+and the time you update it. Even this simple code fragment has the
+possibility of error:
+
+ use threads;
+ my $a :shared = 2;
+ my $b :shared;
+ my $c :shared;
+ my $thr1 = threads->create(sub { $b = $a; $a = $b + 1; });
+ my $thr2 = threads->create(sub { $c = $a; $a = $c + 1; });
+ $thr1->join();
+ $thr2->join();
+
+Two threads both access C<$a>. Each thread can potentially be interrupted
+at any point, or be executed in any order. At the end, C<$a> could be 3
+or 4, and both C<$b> and C<$c> could be 2 or 3.
+
+Even C<$a += 5> or C<$a++> are not guaranteed to be atomic.
+
+Whenever your program accesses data or resources that can be accessed
+by other threads, you must take steps to coordinate access or risk
+data inconsistency and race conditions. Note that Perl will protect its
+internals from your race conditions, but it won't protect you from you.
+
+=head1 Synchronization and control
+
+Perl provides a number of mechanisms to coordinate the interactions
+between themselves and their data, to avoid race conditions and the like.
+Some of these are designed to resemble the common techniques used in thread
+libraries such as C<pthreads>; others are Perl-specific. Often, the
+standard techniques are clumsy and difficult to get right (such as
+condition waits). Where possible, it is usually easier to use Perlish
+techniques such as queues, which remove some of the hard work involved.
+
+=head2 Controlling access: lock()
+
+The C<lock()> function takes a shared variable and puts a lock on it.
+No other thread may lock the variable until the variable is unlocked
+by the thread holding the lock. Unlocking happens automatically
+when the locking thread exits the block that contains the call to the
+C<lock()> function. Using C<lock()> is straightforward: This example has
+several threads doing some calculations in parallel, and occasionally
+updating a running total:
+
+ use threads;
+ use threads::shared;
+
+ my $total :shared = 0;
+
+ sub calc {
+ while (1) {
+ my $result;
+ # (... do some calculations and set $result ...)
+ {
+ lock($total); # Block until we obtain the lock
+ $total += $result;
+ } # Lock implicitly released at end of scope
+ last if $result == 0;
+ }
+ }
+
+ my $thr1 = threads->create(\&calc);
+ my $thr2 = threads->create(\&calc);
+ my $thr3 = threads->create(\&calc);
+ $thr1->join();
+ $thr2->join();
+ $thr3->join();
+ print("total=$total\n");
+
+C<lock()> blocks the thread until the variable being locked is
+available. When C<lock()> returns, your thread can be sure that no other
+thread can lock that variable until the block containing the
+lock exits.
+
+It's important to note that locks don't prevent access to the variable
+in question, only lock attempts. This is in keeping with Perl's
+longstanding tradition of courteous programming, and the advisory file
+locking that C<flock()> gives you.
+
+You may lock arrays and hashes as well as scalars. Locking an array,
+though, will not block subsequent locks on array elements, just lock
+attempts on the array itself.
+
+Locks are recursive, which means it's okay for a thread to
+lock a variable more than once. The lock will last until the outermost
+C<lock()> on the variable goes out of scope. For example:
+
+ my $x :shared;
+ doit();
+
+ sub doit {
+ {
+ {
+ lock($x); # Wait for lock
+ lock($x); # NOOP - we already have the lock
+ {
+ lock($x); # NOOP
+ {
+ lock($x); # NOOP
+ lockit_some_more();
+ }
+ }
+ } # *** Implicit unlock here ***
+ }
+ }
+
+ sub lockit_some_more {
+ lock($x); # NOOP
+ } # Nothing happens here
+
+Note that there is no C<unlock()> function - the only way to unlock a
+variable is to allow it to go out of scope.
+
+A lock can either be used to guard the data contained within the variable
+being locked, or it can be used to guard something else, like a section
+of code. In this latter case, the variable in question does not hold any
+useful data, and exists only for the purpose of being locked. In this
+respect, the variable behaves like the mutexes and basic semaphores of
+traditional thread libraries.
+
+=head2 A Thread Pitfall: Deadlocks
+
+Locks are a handy tool to synchronize access to data, and using them
+properly is the key to safe shared data. Unfortunately, locks aren't
+without their dangers, especially when multiple locks are involved.
+Consider the following code:
+
+ use threads;
+
+ my $a :shared = 4;
+ my $b :shared = 'foo';
+ my $thr1 = threads->create(sub {
+ lock($a);
+ sleep(20);
+ lock($b);
+ });
+ my $thr2 = threads->create(sub {
+ lock($b);
+ sleep(20);
+ lock($a);
+ });
+
+This program will probably hang until you kill it. The only way it
+won't hang is if one of the two threads acquires both locks
+first. A guaranteed-to-hang version is more complicated, but the
+principle is the same.
+
+The first thread will grab a lock on C<$a>, then, after a pause during which
+the second thread has probably had time to do some work, try to grab a
+lock on C<$b>. Meanwhile, the second thread grabs a lock on C<$b>, then later
+tries to grab a lock on C<$a>. The second lock attempt for both threads will
+block, each waiting for the other to release its lock.
+
+This condition is called a deadlock, and it occurs whenever two or
+more threads are trying to get locks on resources that the others
+own. Each thread will block, waiting for the other to release a lock
+on a resource. That never happens, though, since the thread with the
+resource is itself waiting for a lock to be released.
+
+There are a number of ways to handle this sort of problem. The best
+way is to always have all threads acquire locks in the exact same
+order. If, for example, you lock variables C<$a>, C<$b>, and C<$c>, always lock
+C<$a> before C<$b>, and C<$b> before C<$c>. It's also best to hold on to locks for
+as short a period of time to minimize the risks of deadlock.
+
+The other synchronization primitives described below can suffer from
+similar problems.
+
+=head2 Queues: Passing Data Around
+
+A queue is a special thread-safe object that lets you put data in one
+end and take it out the other without having to worry about
+synchronization issues. They're pretty straightforward, and look like
+this:
+
+ use threads;
+ use Thread::Queue;
+
+ my $DataQueue = Thread::Queue->new();
+ my $thr = threads->create(sub {
+ while (my $DataElement = $DataQueue->dequeue()) {
+ print("Popped $DataElement off the queue\n");
+ }
+ });
+
+ $DataQueue->enqueue(12);
+ $DataQueue->enqueue("A", "B", "C");
+ sleep(10);
+ $DataQueue->enqueue(undef);
+ $thr->join();
+
+You create the queue with C<Thread::Queue-E<gt>new()>. Then you can
+add lists of scalars onto the end with C<enqueue()>, and pop scalars off
+the front of it with C<dequeue()>. A queue has no fixed size, and can grow
+as needed to hold everything pushed on to it.
+
+If a queue is empty, C<dequeue()> blocks until another thread enqueues
+something. This makes queues ideal for event loops and other
+communications between threads.
+
+=head2 Semaphores: Synchronizing Data Access
+
+Semaphores are a kind of generic locking mechanism. In their most basic
+form, they behave very much like lockable scalars, except that they
+can't hold data, and that they must be explicitly unlocked. In their
+advanced form, they act like a kind of counter, and can allow multiple
+threads to have the I<lock> at any one time.
+
+=head2 Basic semaphores
+
+Semaphores have two methods, C<down()> and C<up()>: C<down()> decrements the resource
+count, while C<up()> increments it. Calls to C<down()> will block if the
+semaphore's current count would decrement below zero. This program
+gives a quick demonstration:
+
+ use threads;
+ use Thread::Semaphore;
+
+ my $semaphore = Thread::Semaphore->new();
+ my $GlobalVariable :shared = 0;
+
+ $thr1 = threads->create(\&sample_sub, 1);
+ $thr2 = threads->create(\&sample_sub, 2);
+ $thr3 = threads->create(\&sample_sub, 3);
+
+ sub sample_sub {
+ my $SubNumber = shift(@_);
+ my $TryCount = 10;
+ my $LocalCopy;
+ sleep(1);
+ while ($TryCount--) {
+ $semaphore->down();
+ $LocalCopy = $GlobalVariable;
+ print("$TryCount tries left for sub $SubNumber (\$GlobalVariable is $GlobalVariable)\n");
+ sleep(2);
+ $LocalCopy++;
+ $GlobalVariable = $LocalCopy;
+ $semaphore->up();
+ }
+ }
+
+ $thr1->join();
+ $thr2->join();
+ $thr3->join();
+
+The three invocations of the subroutine all operate in sync. The
+semaphore, though, makes sure that only one thread is accessing the
+global variable at once.
+
+=head2 Advanced Semaphores
+
+By default, semaphores behave like locks, letting only one thread
+C<down()> them at a time. However, there are other uses for semaphores.
+
+Each semaphore has a counter attached to it. By default, semaphores are
+created with the counter set to one, C<down()> decrements the counter by
+one, and C<up()> increments by one. However, we can override any or all
+of these defaults simply by passing in different values:
+
+ use threads;
+ use Thread::Semaphore;
+
+ my $semaphore = Thread::Semaphore->new(5);
+ # Creates a semaphore with the counter set to five
+
+ my $thr1 = threads->create(\&sub1);
+ my $thr2 = threads->create(\&sub1);
+
+ sub sub1 {
+ $semaphore->down(5); # Decrements the counter by five
+ # Do stuff here
+ $semaphore->up(5); # Increment the counter by five
+ }
+
+ $thr1->detach();
+ $thr2->detach();
+
+If C<down()> attempts to decrement the counter below zero, it blocks until
+the counter is large enough. Note that while a semaphore can be created
+with a starting count of zero, any C<up()> or C<down()> always changes the
+counter by at least one, and so C<< $semaphore->down(0) >> is the same as
+C<< $semaphore->down(1) >>.
+
+The question, of course, is why would you do something like this? Why
+create a semaphore with a starting count that's not one, or why
+decrement or increment it by more than one? The answer is resource
+availability. Many resources that you want to manage access for can be
+safely used by more than one thread at once.
+
+For example, let's take a GUI driven program. It has a semaphore that
+it uses to synchronize access to the display, so only one thread is
+ever drawing at once. Handy, but of course you don't want any thread
+to start drawing until things are properly set up. In this case, you
+can create a semaphore with a counter set to zero, and up it when
+things are ready for drawing.
+
+Semaphores with counters greater than one are also useful for
+establishing quotas. Say, for example, that you have a number of
+threads that can do I/O at once. You don't want all the threads
+reading or writing at once though, since that can potentially swamp
+your I/O channels, or deplete your process's quota of filehandles. You
+can use a semaphore initialized to the number of concurrent I/O
+requests (or open files) that you want at any one time, and have your
+threads quietly block and unblock themselves.
+
+Larger increments or decrements are handy in those cases where a
+thread needs to check out or return a number of resources at once.
+
+=head2 Waiting for a Condition
+
+The functions C<cond_wait()> and C<cond_signal()>
+can be used in conjunction with locks to notify
+co-operating threads that a resource has become available. They are
+very similar in use to the functions found in C<pthreads>. However
+for most purposes, queues are simpler to use and more intuitive. See
+L<threads::shared> for more details.
+
+=head2 Giving up control
+
+There are times when you may find it useful to have a thread
+explicitly give up the CPU to another thread. You may be doing something
+processor-intensive and want to make sure that the user-interface thread
+gets called frequently. Regardless, there are times that you might want
+a thread to give up the processor.
+
+Perl's threading package provides the C<yield()> function that does
+this. C<yield()> is pretty straightforward, and works like this:
+
+ use threads;
+
+ sub loop {
+ my $thread = shift;
+ my $foo = 50;
+ while($foo--) { print("In thread $thread\n"); }
+ threads->yield();
+ $foo = 50;
+ while($foo--) { print("In thread $thread\n"); }
+ }
+
+ my $thr1 = threads->create(\&loop, 'first');
+ my $thr2 = threads->create(\&loop, 'second');
+ my $thr3 = threads->create(\&loop, 'third');
+
+It is important to remember that C<yield()> is only a hint to give up the CPU,
+it depends on your hardware, OS and threading libraries what actually happens.
+B<On many operating systems, yield() is a no-op.> Therefore it is important
+to note that one should not build the scheduling of the threads around
+C<yield()> calls. It might work on your platform but it won't work on another
+platform.
+
+=head1 General Thread Utility Routines
+
+We've covered the workhorse parts of Perl's threading package, and
+with these tools you should be well on your way to writing threaded
+code and packages. There are a few useful little pieces that didn't
+really fit in anyplace else.
+
+=head2 What Thread Am I In?
+
+The C<threads-E<gt>self()> class method provides your program with a way to
+get an object representing the thread it's currently in. You can use this
+object in the same way as the ones returned from thread creation.
+
+=head2 Thread IDs
+
+C<tid()> is a thread object method that returns the thread ID of the
+thread the object represents. Thread IDs are integers, with the main
+thread in a program being 0. Currently Perl assigns a unique TID to
+every thread ever created in your program, assigning the first thread
+to be created a TID of 1, and increasing the TID by 1 for each new
+thread that's created. When used as a class method, C<threads-E<gt>tid()>
+can be used by a thread to get its own TID.
+
+=head2 Are These Threads The Same?
+
+The C<equal()> method takes two thread objects and returns true
+if the objects represent the same thread, and false if they don't.
+
+Thread objects also have an overloaded C<==> comparison so that you can do
+comparison on them as you would with normal objects.
+
+=head2 What Threads Are Running?
+
+C<threads-E<gt>list()> returns a list of thread objects, one for each thread
+that's currently running and not detached. Handy for a number of things,
+including cleaning up at the end of your program (from the main Perl thread,
+of course):
+
+ # Loop through all the threads
+ foreach my $thr (threads->list()) {
+ $thr->join();
+ }
+
+If some threads have not finished running when the main Perl thread
+ends, Perl will warn you about it and die, since it is impossible for Perl
+to clean up itself while other threads are running.
+
+NOTE: The main Perl thread (thread 0) is in a I<detached> state, and so
+does not appear in the list returned by C<threads-E<gt>list()>.
+
+=head1 A Complete Example
+
+Confused yet? It's time for an example program to show some of the
+things we've covered. This program finds prime numbers using threads.
+
+ 1 #!/usr/bin/perl
+ 2 # prime-pthread, courtesy of Tom Christiansen
+ 3
+ 4 use strict;
+ 5 use warnings;
+ 6
+ 7 use threads;
+ 8 use Thread::Queue;
+ 9
+ 10 sub check_num {
+ 11 my ($upstream, $cur_prime) = @_;
+ 12 my $kid;
+ 13 my $downstream = Thread::Queue->new();
+ 14 while (my $num = $upstream->dequeue()) {
+ 15 next unless ($num % $cur_prime);
+ 16 if ($kid) {
+ 17 $downstream->enqueue($num);
+ 18 } else {
+ 19 print("Found prime: $num\n");
+ 20 $kid = threads->create(\&check_num, $downstream, $num);
+ 21 if (! $kid) {
+ 22 warn("Sorry. Ran out of threads.\n");
+ 23 last;
+ 24 }
+ 25 }
+ 26 }
+ 27 if ($kid) {
+ 28 $downstream->enqueue(undef);
+ 29 $kid->join();
+ 30 }
+ 31 }
+ 32
+ 33 my $stream = Thread::Queue->new(3..1000, undef);
+ 34 check_num($stream, 2);
+
+This program uses the pipeline model to generate prime numbers. Each
+thread in the pipeline has an input queue that feeds numbers to be
+checked, a prime number that it's responsible for, and an output queue
+into which it funnels numbers that have failed the check. If the thread
+has a number that's failed its check and there's no child thread, then
+the thread must have found a new prime number. In that case, a new
+child thread is created for that prime and stuck on the end of the
+pipeline.
+
+This probably sounds a bit more confusing than it really is, so let's
+go through this program piece by piece and see what it does. (For
+those of you who might be trying to remember exactly what a prime
+number is, it's a number that's only evenly divisible by itself and 1.)
+
+The bulk of the work is done by the C<check_num()> subroutine, which
+takes a reference to its input queue and a prime number that it's
+responsible for. After pulling in the input queue and the prime that
+the subroutine is checking (line 11), we create a new queue (line 13)
+and reserve a scalar for the thread that we're likely to create later
+(line 12).
+
+The while loop from line 14 to line 26 grabs a scalar off the input
+queue and checks against the prime this thread is responsible
+for. Line 15 checks to see if there's a remainder when we divide the
+number to be checked by our prime. If there is one, the number
+must not be evenly divisible by our prime, so we need to either pass
+it on to the next thread if we've created one (line 17) or create a
+new thread if we haven't.
+
+The new thread creation is line 20. We pass on to it a reference to
+the queue we've created, and the prime number we've found. In lines 21
+through 24, we check to make sure that our new thread got created, and
+if not, we stop checking any remaining numbers in the queue.
+
+Finally, once the loop terminates (because we got a 0 or C<undef> in the
+queue, which serves as a note to terminate), we pass on the notice to our
+child, and wait for it to exit if we've created a child (lines 27 and
+30).
+
+Meanwhile, back in the main thread, we first create a queue (line 33) and
+queue up all the numbers from 3 to 1000 for checking, plus a termination
+notice. Then all we have to do to get the ball rolling is pass the queue
+and the first prime to the C<check_num()> subroutine (line 34).
+
+That's how it works. It's pretty simple; as with many Perl programs,
+the explanation is much longer than the program.
+
+=head1 Different implementations of threads
+
+Some background on thread implementations from the operating system
+viewpoint. There are three basic categories of threads: user-mode threads,
+kernel threads, and multiprocessor kernel threads.
+
+User-mode threads are threads that live entirely within a program and
+its libraries. In this model, the OS knows nothing about threads. As
+far as it's concerned, your process is just a process.
+
+This is the easiest way to implement threads, and the way most OSes
+start. The big disadvantage is that, since the OS knows nothing about
+threads, if one thread blocks they all do. Typical blocking activities
+include most system calls, most I/O, and things like C<sleep()>.
+
+Kernel threads are the next step in thread evolution. The OS knows
+about kernel threads, and makes allowances for them. The main
+difference between a kernel thread and a user-mode thread is
+blocking. With kernel threads, things that block a single thread don't
+block other threads. This is not the case with user-mode threads,
+where the kernel blocks at the process level and not the thread level.
+
+This is a big step forward, and can give a threaded program quite a
+performance boost over non-threaded programs. Threads that block
+performing I/O, for example, won't block threads that are doing other
+things. Each process still has only one thread running at once,
+though, regardless of how many CPUs a system might have.
+
+Since kernel threading can interrupt a thread at any time, they will
+uncover some of the implicit locking assumptions you may make in your
+program. For example, something as simple as C<$a = $a + 2> can behave
+unpredictably with kernel threads if C<$a> is visible to other
+threads, as another thread may have changed C<$a> between the time it
+was fetched on the right hand side and the time the new value is
+stored.
+
+Multiprocessor kernel threads are the final step in thread
+support. With multiprocessor kernel threads on a machine with multiple
+CPUs, the OS may schedule two or more threads to run simultaneously on
+different CPUs.
+
+This can give a serious performance boost to your threaded program,
+since more than one thread will be executing at the same time. As a
+tradeoff, though, any of those nagging synchronization issues that
+might not have shown with basic kernel threads will appear with a
+vengeance.
+
+In addition to the different levels of OS involvement in threads,
+different OSes (and different thread implementations for a particular
+OS) allocate CPU cycles to threads in different ways.
+
+Cooperative multitasking systems have running threads give up control
+if one of two things happen. If a thread calls a yield function, it
+gives up control. It also gives up control if the thread does
+something that would cause it to block, such as perform I/O. In a
+cooperative multitasking implementation, one thread can starve all the
+others for CPU time if it so chooses.
+
+Preemptive multitasking systems interrupt threads at regular intervals
+while the system decides which thread should run next. In a preemptive
+multitasking system, one thread usually won't monopolize the CPU.
+
+On some systems, there can be cooperative and preemptive threads
+running simultaneously. (Threads running with realtime priorities
+often behave cooperatively, for example, while threads running at
+normal priorities behave preemptively.)
+
+Most modern operating systems support preemptive multitasking nowadays.
+
+=head1 Performance considerations
+
+The main thing to bear in mind when comparing Perl's I<ithreads> to other threading
+models is the fact that for each new thread created, a complete copy of
+all the variables and data of the parent thread has to be taken. Thus,
+thread creation can be quite expensive, both in terms of memory usage and
+time spent in creation. The ideal way to reduce these costs is to have a
+relatively short number of long-lived threads, all created fairly early
+on (before the base thread has accumulated too much data). Of course, this
+may not always be possible, so compromises have to be made. However, after
+a thread has been created, its performance and extra memory usage should
+be little different than ordinary code.
+
+Also note that under the current implementation, shared variables
+use a little more memory and are a little slower than ordinary variables.
+
+=head1 Process-scope Changes
+
+Note that while threads themselves are separate execution threads and
+Perl data is thread-private unless explicitly shared, the threads can
+affect process-scope state, affecting all the threads.
+
+The most common example of this is changing the current working
+directory using C<chdir()>. One thread calls C<chdir()>, and the working
+directory of all the threads changes.
+
+Even more drastic example of a process-scope change is C<chroot()>:
+the root directory of all the threads changes, and no thread can
+undo it (as opposed to C<chdir()>).
+
+Further examples of process-scope changes include C<umask()> and
+changing uids and gids.
+
+Thinking of mixing C<fork()> and threads? Please lie down and wait
+until the feeling passes. Be aware that the semantics of C<fork()> vary
+between platforms. For example, some Unix systems copy all the current
+threads into the child process, while others only copy the thread that
+called C<fork()>. You have been warned!
+
+Similarly, mixing signals and threads may be problematic.
+Implementations are platform-dependent, and even the POSIX
+semantics may not be what you expect (and Perl doesn't even
+give you the full POSIX API). For example, there is no way to
+guarantee that a signal sent to a multi-threaded Perl application
+will get intercepted by any particular thread. (However, a recently
+added feature does provide the capability to send signals between
+threads. See L<threads/"THREAD SIGNALLING> for more details.)
+
+=head1 Thread-Safety of System Libraries
+
+Whether various library calls are thread-safe is outside the control
+of Perl. Calls often suffering from not being thread-safe include:
+C<localtime()>, C<gmtime()>, functions fetching user, group and
+network information (such as C<getgrent()>, C<gethostent()>,
+C<getnetent()> and so on), C<readdir()>, C<rand()>, and C<srand()>. In
+general, calls that depend on some global external state.
+
+If the system Perl is compiled in has thread-safe variants of such
+calls, they will be used. Beyond that, Perl is at the mercy of
+the thread-safety or -unsafety of the calls. Please consult your
+C library call documentation.
+
+On some platforms the thread-safe library interfaces may fail if the
+result buffer is too small (for example the user group databases may
+be rather large, and the reentrant interfaces may have to carry around
+a full snapshot of those databases). Perl will start with a small
+buffer, but keep retrying and growing the result buffer
+until the result fits. If this limitless growing sounds bad for
+security or memory consumption reasons you can recompile Perl with
+C<PERL_REENTRANT_MAXSIZE> defined to the maximum number of bytes you will
+allow.
+
+=head1 Conclusion
+
+A complete thread tutorial could fill a book (and has, many times),
+but with what we've covered in this introduction, you should be well
+on your way to becoming a threaded Perl expert.
+
+=head1 SEE ALSO
+
+Annotated POD for L<threads>:
+L<http://annocpan.org/?mode=search&field=Module&name=threads>
+
+Lastest version of L<threads> on CPAN:
+L<http://search.cpan.org/search?module=threads>
+
+Annotated POD for L<threads::shared>:
+L<http://annocpan.org/?mode=search&field=Module&name=threads%3A%3Ashared>
+
+Lastest version of L<threads::shared> on CPAN:
+L<http://search.cpan.org/search?module=threads%3A%3Ashared>
+
+Perl threads mailing list:
+L<http://lists.cpan.org/showlist.cgi?name=iThreads>
+
+=head1 Bibliography
+
+Here's a short bibliography courtesy of Jürgen Christoffel:
+
+=head2 Introductory Texts
+
+Birrell, Andrew D. An Introduction to Programming with
+Threads. Digital Equipment Corporation, 1989, DEC-SRC Research Report
+#35 online as
+ftp://ftp.dec.com/pub/DEC/SRC/research-reports/SRC-035.pdf
+(highly recommended)
+
+Robbins, Kay. A., and Steven Robbins. Practical Unix Programming: A
+Guide to Concurrency, Communication, and
+Multithreading. Prentice-Hall, 1996.
+
+Lewis, Bill, and Daniel J. Berg. Multithreaded Programming with
+Pthreads. Prentice Hall, 1997, ISBN 0-13-443698-9 (a well-written
+introduction to threads).
+
+Nelson, Greg (editor). Systems Programming with Modula-3. Prentice
+Hall, 1991, ISBN 0-13-590464-1.
+
+Nichols, Bradford, Dick Buttlar, and Jacqueline Proulx Farrell.
+Pthreads Programming. O'Reilly & Associates, 1996, ISBN 156592-115-1
+(covers POSIX threads).
+
+=head2 OS-Related References
+
+Boykin, Joseph, David Kirschen, Alan Langerman, and Susan
+LoVerso. Programming under Mach. Addison-Wesley, 1994, ISBN
+0-201-52739-1.
+
+Tanenbaum, Andrew S. Distributed Operating Systems. Prentice Hall,
+1995, ISBN 0-13-219908-4 (great textbook).
+
+Silberschatz, Abraham, and Peter B. Galvin. Operating System Concepts,
+4th ed. Addison-Wesley, 1995, ISBN 0-201-59292-4
+
+=head2 Other References
+
+Arnold, Ken and James Gosling. The Java Programming Language, 2nd
+ed. Addison-Wesley, 1998, ISBN 0-201-31006-6.
+
+comp.programming.threads FAQ,
+L<http://www.serpentine.com/~bos/threads-faq/>
+
+Le Sergent, T. and B. Berthomieu. "Incremental MultiThreaded Garbage
+Collection on Virtually Shared Memory Architectures" in Memory
+Management: Proc. of the International Workshop IWMM 92, St. Malo,
+France, September 1992, Yves Bekkers and Jacques Cohen, eds. Springer,
+1992, ISBN 3540-55940-X (real-life thread applications).
+
+Artur Bergman, "Where Wizards Fear To Tread", June 11, 2002,
+L<http://www.perl.com/pub/a/2002/06/11/threads.html>
+
+=head1 Acknowledgements
+
+Thanks (in no particular order) to Chaim Frenkel, Steve Fink, Gurusamy
+Sarathy, Ilya Zakharevich, Benjamin Sugars, Jürgen Christoffel, Joshua
+Pritikin, and Alan Burlison, for their help in reality-checking and
+polishing this article. Big thanks to Tom Christiansen for his rewrite
+of the prime number generator.
+
+=head1 AUTHOR
+
+Dan Sugalski E<lt>dan@sidhe.org<gt>
+
+Slightly modified by Arthur Bergman to fit the new thread model/module.
+
+Reworked slightly by Jörg Walter E<lt>jwalt@cpan.org<gt> to be more concise
+about thread-safety of Perl code.
+
+Rearranged slightly by Elizabeth Mattijsen E<lt>liz@dijkmat.nl<gt> to put
+less emphasis on yield().
+
+=head1 Copyrights
+
+The original version of this article originally appeared in The Perl
+Journal #10, and is copyright 1998 The Perl Journal. It appears courtesy
+of Jon Orwant and The Perl Journal. This document may be distributed
+under the same terms as Perl itself.
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perltie.pod b/Master/tlpkg/tlperl/lib/pods/perltie.pod
new file mode 100644
index 00000000000..370f644209d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltie.pod
@@ -0,0 +1,1204 @@
+=head1 NAME
+X<tie>
+
+perltie - how to hide an object class in a simple variable
+
+=head1 SYNOPSIS
+
+ tie VARIABLE, CLASSNAME, LIST
+
+ $object = tied VARIABLE
+
+ untie VARIABLE
+
+=head1 DESCRIPTION
+
+Prior to release 5.0 of Perl, a programmer could use dbmopen()
+to connect an on-disk database in the standard Unix dbm(3x)
+format magically to a %HASH in their program. However, their Perl was either
+built with one particular dbm library or another, but not both, and
+you couldn't extend this mechanism to other packages or types of variables.
+
+Now you can.
+
+The tie() function binds a variable to a class (package) that will provide
+the implementation for access methods for that variable. Once this magic
+has been performed, accessing a tied variable automatically triggers
+method calls in the proper class. The complexity of the class is
+hidden behind magic methods calls. The method names are in ALL CAPS,
+which is a convention that Perl uses to indicate that they're called
+implicitly rather than explicitly--just like the BEGIN() and END()
+functions.
+
+In the tie() call, C<VARIABLE> is the name of the variable to be
+enchanted. C<CLASSNAME> is the name of a class implementing objects of
+the correct type. Any additional arguments in the C<LIST> are passed to
+the appropriate constructor method for that class--meaning TIESCALAR(),
+TIEARRAY(), TIEHASH(), or TIEHANDLE(). (Typically these are arguments
+such as might be passed to the dbminit() function of C.) The object
+returned by the "new" method is also returned by the tie() function,
+which would be useful if you wanted to access other methods in
+C<CLASSNAME>. (You don't actually have to return a reference to a right
+"type" (e.g., HASH or C<CLASSNAME>) so long as it's a properly blessed
+object.) You can also retrieve a reference to the underlying object
+using the tied() function.
+
+Unlike dbmopen(), the tie() function will not C<use> or C<require> a module
+for you--you need to do that explicitly yourself.
+
+=head2 Tying Scalars
+X<scalar, tying>
+
+A class implementing a tied scalar should define the following methods:
+TIESCALAR, FETCH, STORE, and possibly UNTIE and/or DESTROY.
+
+Let's look at each in turn, using as an example a tie class for
+scalars that allows the user to do something like:
+
+ tie $his_speed, 'Nice', getppid();
+ tie $my_speed, 'Nice', $$;
+
+And now whenever either of those variables is accessed, its current
+system priority is retrieved and returned. If those variables are set,
+then the process's priority is changed!
+
+We'll use Jarkko Hietaniemi <F<jhi@iki.fi>>'s BSD::Resource class (not
+included) to access the PRIO_PROCESS, PRIO_MIN, and PRIO_MAX constants
+from your system, as well as the getpriority() and setpriority() system
+calls. Here's the preamble of the class.
+
+ package Nice;
+ use Carp;
+ use BSD::Resource;
+ use strict;
+ $Nice::DEBUG = 0 unless defined $Nice::DEBUG;
+
+=over 4
+
+=item TIESCALAR classname, LIST
+X<TIESCALAR>
+
+This is the constructor for the class. That means it is
+expected to return a blessed reference to a new scalar
+(probably anonymous) that it's creating. For example:
+
+ sub TIESCALAR {
+ my $class = shift;
+ my $pid = shift || $$; # 0 means me
+
+ if ($pid !~ /^\d+$/) {
+ carp "Nice::Tie::Scalar got non-numeric pid $pid" if $^W;
+ return undef;
+ }
+
+ unless (kill 0, $pid) { # EPERM or ERSCH, no doubt
+ carp "Nice::Tie::Scalar got bad pid $pid: $!" if $^W;
+ return undef;
+ }
+
+ return bless \$pid, $class;
+ }
+
+This tie class has chosen to return an error rather than raising an
+exception if its constructor should fail. While this is how dbmopen() works,
+other classes may well not wish to be so forgiving. It checks the global
+variable C<$^W> to see whether to emit a bit of noise anyway.
+
+=item FETCH this
+X<FETCH>
+
+This method will be triggered every time the tied variable is accessed
+(read). It takes no arguments beyond its self reference, which is the
+object representing the scalar we're dealing with. Because in this case
+we're using just a SCALAR ref for the tied scalar object, a simple $$self
+allows the method to get at the real value stored there. In our example
+below, that real value is the process ID to which we've tied our variable.
+
+ sub FETCH {
+ my $self = shift;
+ confess "wrong type" unless ref $self;
+ croak "usage error" if @_;
+ my $nicety;
+ local($!) = 0;
+ $nicety = getpriority(PRIO_PROCESS, $$self);
+ if ($!) { croak "getpriority failed: $!" }
+ return $nicety;
+ }
+
+This time we've decided to blow up (raise an exception) if the renice
+fails--there's no place for us to return an error otherwise, and it's
+probably the right thing to do.
+
+=item STORE this, value
+X<STORE>
+
+This method will be triggered every time the tied variable is set
+(assigned). Beyond its self reference, it also expects one (and only one)
+argument: the new value the user is trying to assign. Don't worry about
+returning a value from STORE; the semantic of assignment returning the
+assigned value is implemented with FETCH.
+
+ sub STORE {
+ my $self = shift;
+ confess "wrong type" unless ref $self;
+ my $new_nicety = shift;
+ croak "usage error" if @_;
+
+ if ($new_nicety < PRIO_MIN) {
+ carp sprintf
+ "WARNING: priority %d less than minimum system priority %d",
+ $new_nicety, PRIO_MIN if $^W;
+ $new_nicety = PRIO_MIN;
+ }
+
+ if ($new_nicety > PRIO_MAX) {
+ carp sprintf
+ "WARNING: priority %d greater than maximum system priority %d",
+ $new_nicety, PRIO_MAX if $^W;
+ $new_nicety = PRIO_MAX;
+ }
+
+ unless (defined setpriority(PRIO_PROCESS, $$self, $new_nicety)) {
+ confess "setpriority failed: $!";
+ }
+ }
+
+=item UNTIE this
+X<UNTIE>
+
+This method will be triggered when the C<untie> occurs. This can be useful
+if the class needs to know when no further calls will be made. (Except DESTROY
+of course.) See L<The C<untie> Gotcha> below for more details.
+
+=item DESTROY this
+X<DESTROY>
+
+This method will be triggered when the tied variable needs to be destructed.
+As with other object classes, such a method is seldom necessary, because Perl
+deallocates its moribund object's memory for you automatically--this isn't
+C++, you know. We'll use a DESTROY method here for debugging purposes only.
+
+ sub DESTROY {
+ my $self = shift;
+ confess "wrong type" unless ref $self;
+ carp "[ Nice::DESTROY pid $$self ]" if $Nice::DEBUG;
+ }
+
+=back
+
+That's about all there is to it. Actually, it's more than all there
+is to it, because we've done a few nice things here for the sake
+of completeness, robustness, and general aesthetics. Simpler
+TIESCALAR classes are certainly possible.
+
+=head2 Tying Arrays
+X<array, tying>
+
+A class implementing a tied ordinary array should define the following
+methods: TIEARRAY, FETCH, STORE, FETCHSIZE, STORESIZE and perhaps UNTIE and/or DESTROY.
+
+FETCHSIZE and STORESIZE are used to provide C<$#array> and
+equivalent C<scalar(@array)> access.
+
+The methods POP, PUSH, SHIFT, UNSHIFT, SPLICE, DELETE, and EXISTS are
+required if the perl operator with the corresponding (but lowercase) name
+is to operate on the tied array. The B<Tie::Array> class can be used as a
+base class to implement the first five of these in terms of the basic
+methods above. The default implementations of DELETE and EXISTS in
+B<Tie::Array> simply C<croak>.
+
+In addition EXTEND will be called when perl would have pre-extended
+allocation in a real array.
+
+For this discussion, we'll implement an array whose elements are a fixed
+size at creation. If you try to create an element larger than the fixed
+size, you'll take an exception. For example:
+
+ use FixedElem_Array;
+ tie @array, 'FixedElem_Array', 3;
+ $array[0] = 'cat'; # ok.
+ $array[1] = 'dogs'; # exception, length('dogs') > 3.
+
+The preamble code for the class is as follows:
+
+ package FixedElem_Array;
+ use Carp;
+ use strict;
+
+=over 4
+
+=item TIEARRAY classname, LIST
+X<TIEARRAY>
+
+This is the constructor for the class. That means it is expected to
+return a blessed reference through which the new array (probably an
+anonymous ARRAY ref) will be accessed.
+
+In our example, just to show you that you don't I<really> have to return an
+ARRAY reference, we'll choose a HASH reference to represent our object.
+A HASH works out well as a generic record type: the C<{ELEMSIZE}> field will
+store the maximum element size allowed, and the C<{ARRAY}> field will hold the
+true ARRAY ref. If someone outside the class tries to dereference the
+object returned (doubtless thinking it an ARRAY ref), they'll blow up.
+This just goes to show you that you should respect an object's privacy.
+
+ sub TIEARRAY {
+ my $class = shift;
+ my $elemsize = shift;
+ if ( @_ || $elemsize =~ /\D/ ) {
+ croak "usage: tie ARRAY, '" . __PACKAGE__ . "', elem_size";
+ }
+ return bless {
+ ELEMSIZE => $elemsize,
+ ARRAY => [],
+ }, $class;
+ }
+
+=item FETCH this, index
+X<FETCH>
+
+This method will be triggered every time an individual element the tied array
+is accessed (read). It takes one argument beyond its self reference: the
+index whose value we're trying to fetch.
+
+ sub FETCH {
+ my $self = shift;
+ my $index = shift;
+ return $self->{ARRAY}->[$index];
+ }
+
+If a negative array index is used to read from an array, the index
+will be translated to a positive one internally by calling FETCHSIZE
+before being passed to FETCH. You may disable this feature by
+assigning a true value to the variable C<$NEGATIVE_INDICES> in the
+tied array class.
+
+As you may have noticed, the name of the FETCH method (et al.) is the same
+for all accesses, even though the constructors differ in names (TIESCALAR
+vs TIEARRAY). While in theory you could have the same class servicing
+several tied types, in practice this becomes cumbersome, and it's easiest
+to keep them at simply one tie type per class.
+
+=item STORE this, index, value
+X<STORE>
+
+This method will be triggered every time an element in the tied array is set
+(written). It takes two arguments beyond its self reference: the index at
+which we're trying to store something and the value we're trying to put
+there.
+
+In our example, C<undef> is really C<$self-E<gt>{ELEMSIZE}> number of
+spaces so we have a little more work to do here:
+
+ sub STORE {
+ my $self = shift;
+ my( $index, $value ) = @_;
+ if ( length $value > $self->{ELEMSIZE} ) {
+ croak "length of $value is greater than $self->{ELEMSIZE}";
+ }
+ # fill in the blanks
+ $self->EXTEND( $index ) if $index > $self->FETCHSIZE();
+ # right justify to keep element size for smaller elements
+ $self->{ARRAY}->[$index] = sprintf "%$self->{ELEMSIZE}s", $value;
+ }
+
+Negative indexes are treated the same as with FETCH.
+
+=item FETCHSIZE this
+X<FETCHSIZE>
+
+Returns the total number of items in the tied array associated with
+object I<this>. (Equivalent to C<scalar(@array)>). For example:
+
+ sub FETCHSIZE {
+ my $self = shift;
+ return scalar @{$self->{ARRAY}};
+ }
+
+=item STORESIZE this, count
+X<STORESIZE>
+
+Sets the total number of items in the tied array associated with
+object I<this> to be I<count>. If this makes the array larger then
+class's mapping of C<undef> should be returned for new positions.
+If the array becomes smaller then entries beyond count should be
+deleted.
+
+In our example, 'undef' is really an element containing
+C<$self-E<gt>{ELEMSIZE}> number of spaces. Observe:
+
+ sub STORESIZE {
+ my $self = shift;
+ my $count = shift;
+ if ( $count > $self->FETCHSIZE() ) {
+ foreach ( $count - $self->FETCHSIZE() .. $count ) {
+ $self->STORE( $_, '' );
+ }
+ } elsif ( $count < $self->FETCHSIZE() ) {
+ foreach ( 0 .. $self->FETCHSIZE() - $count - 2 ) {
+ $self->POP();
+ }
+ }
+ }
+
+=item EXTEND this, count
+X<EXTEND>
+
+Informative call that array is likely to grow to have I<count> entries.
+Can be used to optimize allocation. This method need do nothing.
+
+In our example, we want to make sure there are no blank (C<undef>)
+entries, so C<EXTEND> will make use of C<STORESIZE> to fill elements
+as needed:
+
+ sub EXTEND {
+ my $self = shift;
+ my $count = shift;
+ $self->STORESIZE( $count );
+ }
+
+=item EXISTS this, key
+X<EXISTS>
+
+Verify that the element at index I<key> exists in the tied array I<this>.
+
+In our example, we will determine that if an element consists of
+C<$self-E<gt>{ELEMSIZE}> spaces only, it does not exist:
+
+ sub EXISTS {
+ my $self = shift;
+ my $index = shift;
+ return 0 if ! defined $self->{ARRAY}->[$index] ||
+ $self->{ARRAY}->[$index] eq ' ' x $self->{ELEMSIZE};
+ return 1;
+ }
+
+=item DELETE this, key
+X<DELETE>
+
+Delete the element at index I<key> from the tied array I<this>.
+
+In our example, a deleted item is C<$self-E<gt>{ELEMSIZE}> spaces:
+
+ sub DELETE {
+ my $self = shift;
+ my $index = shift;
+ return $self->STORE( $index, '' );
+ }
+
+=item CLEAR this
+X<CLEAR>
+
+Clear (remove, delete, ...) all values from the tied array associated with
+object I<this>. For example:
+
+ sub CLEAR {
+ my $self = shift;
+ return $self->{ARRAY} = [];
+ }
+
+=item PUSH this, LIST
+X<PUSH>
+
+Append elements of I<LIST> to the array. For example:
+
+ sub PUSH {
+ my $self = shift;
+ my @list = @_;
+ my $last = $self->FETCHSIZE();
+ $self->STORE( $last + $_, $list[$_] ) foreach 0 .. $#list;
+ return $self->FETCHSIZE();
+ }
+
+=item POP this
+X<POP>
+
+Remove last element of the array and return it. For example:
+
+ sub POP {
+ my $self = shift;
+ return pop @{$self->{ARRAY}};
+ }
+
+=item SHIFT this
+X<SHIFT>
+
+Remove the first element of the array (shifting other elements down)
+and return it. For example:
+
+ sub SHIFT {
+ my $self = shift;
+ return shift @{$self->{ARRAY}};
+ }
+
+=item UNSHIFT this, LIST
+X<UNSHIFT>
+
+Insert LIST elements at the beginning of the array, moving existing elements
+up to make room. For example:
+
+ sub UNSHIFT {
+ my $self = shift;
+ my @list = @_;
+ my $size = scalar( @list );
+ # make room for our list
+ @{$self->{ARRAY}}[ $size .. $#{$self->{ARRAY}} + $size ]
+ = @{$self->{ARRAY}};
+ $self->STORE( $_, $list[$_] ) foreach 0 .. $#list;
+ }
+
+=item SPLICE this, offset, length, LIST
+X<SPLICE>
+
+Perform the equivalent of C<splice> on the array.
+
+I<offset> is optional and defaults to zero, negative values count back
+from the end of the array.
+
+I<length> is optional and defaults to rest of the array.
+
+I<LIST> may be empty.
+
+Returns a list of the original I<length> elements at I<offset>.
+
+In our example, we'll use a little shortcut if there is a I<LIST>:
+
+ sub SPLICE {
+ my $self = shift;
+ my $offset = shift || 0;
+ my $length = shift || $self->FETCHSIZE() - $offset;
+ my @list = ();
+ if ( @_ ) {
+ tie @list, __PACKAGE__, $self->{ELEMSIZE};
+ @list = @_;
+ }
+ return splice @{$self->{ARRAY}}, $offset, $length, @list;
+ }
+
+=item UNTIE this
+X<UNTIE>
+
+Will be called when C<untie> happens. (See L<The C<untie> Gotcha> below.)
+
+=item DESTROY this
+X<DESTROY>
+
+This method will be triggered when the tied variable needs to be destructed.
+As with the scalar tie class, this is almost never needed in a
+language that does its own garbage collection, so this time we'll
+just leave it out.
+
+=back
+
+=head2 Tying Hashes
+X<hash, tying>
+
+Hashes were the first Perl data type to be tied (see dbmopen()). A class
+implementing a tied hash should define the following methods: TIEHASH is
+the constructor. FETCH and STORE access the key and value pairs. EXISTS
+reports whether a key is present in the hash, and DELETE deletes one.
+CLEAR empties the hash by deleting all the key and value pairs. FIRSTKEY
+and NEXTKEY implement the keys() and each() functions to iterate over all
+the keys. SCALAR is triggered when the tied hash is evaluated in scalar
+context. UNTIE is called when C<untie> happens, and DESTROY is called when
+the tied variable is garbage collected.
+
+If this seems like a lot, then feel free to inherit from merely the
+standard Tie::StdHash module for most of your methods, redefining only the
+interesting ones. See L<Tie::Hash> for details.
+
+Remember that Perl distinguishes between a key not existing in the hash,
+and the key existing in the hash but having a corresponding value of
+C<undef>. The two possibilities can be tested with the C<exists()> and
+C<defined()> functions.
+
+Here's an example of a somewhat interesting tied hash class: it gives you
+a hash representing a particular user's dot files. You index into the hash
+with the name of the file (minus the dot) and you get back that dot file's
+contents. For example:
+
+ use DotFiles;
+ tie %dot, 'DotFiles';
+ if ( $dot{profile} =~ /MANPATH/ ||
+ $dot{login} =~ /MANPATH/ ||
+ $dot{cshrc} =~ /MANPATH/ )
+ {
+ print "you seem to set your MANPATH\n";
+ }
+
+Or here's another sample of using our tied class:
+
+ tie %him, 'DotFiles', 'daemon';
+ foreach $f ( keys %him ) {
+ printf "daemon dot file %s is size %d\n",
+ $f, length $him{$f};
+ }
+
+In our tied hash DotFiles example, we use a regular
+hash for the object containing several important
+fields, of which only the C<{LIST}> field will be what the
+user thinks of as the real hash.
+
+=over 5
+
+=item USER
+
+whose dot files this object represents
+
+=item HOME
+
+where those dot files live
+
+=item CLOBBER
+
+whether we should try to change or remove those dot files
+
+=item LIST
+
+the hash of dot file names and content mappings
+
+=back
+
+Here's the start of F<Dotfiles.pm>:
+
+ package DotFiles;
+ use Carp;
+ sub whowasi { (caller(1))[3] . '()' }
+ my $DEBUG = 0;
+ sub debug { $DEBUG = @_ ? shift : 1 }
+
+For our example, we want to be able to emit debugging info to help in tracing
+during development. We keep also one convenience function around
+internally to help print out warnings; whowasi() returns the function name
+that calls it.
+
+Here are the methods for the DotFiles tied hash.
+
+=over 4
+
+=item TIEHASH classname, LIST
+X<TIEHASH>
+
+This is the constructor for the class. That means it is expected to
+return a blessed reference through which the new object (probably but not
+necessarily an anonymous hash) will be accessed.
+
+Here's the constructor:
+
+ sub TIEHASH {
+ my $self = shift;
+ my $user = shift || $>;
+ my $dotdir = shift || '';
+ croak "usage: @{[&whowasi]} [USER [DOTDIR]]" if @_;
+ $user = getpwuid($user) if $user =~ /^\d+$/;
+ my $dir = (getpwnam($user))[7]
+ || croak "@{[&whowasi]}: no user $user";
+ $dir .= "/$dotdir" if $dotdir;
+
+ my $node = {
+ USER => $user,
+ HOME => $dir,
+ LIST => {},
+ CLOBBER => 0,
+ };
+
+ opendir(DIR, $dir)
+ || croak "@{[&whowasi]}: can't opendir $dir: $!";
+ foreach $dot ( grep /^\./ && -f "$dir/$_", readdir(DIR)) {
+ $dot =~ s/^\.//;
+ $node->{LIST}{$dot} = undef;
+ }
+ closedir DIR;
+ return bless $node, $self;
+ }
+
+It's probably worth mentioning that if you're going to filetest the
+return values out of a readdir, you'd better prepend the directory
+in question. Otherwise, because we didn't chdir() there, it would
+have been testing the wrong file.
+
+=item FETCH this, key
+X<FETCH>
+
+This method will be triggered every time an element in the tied hash is
+accessed (read). It takes one argument beyond its self reference: the key
+whose value we're trying to fetch.
+
+Here's the fetch for our DotFiles example.
+
+ sub FETCH {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ my $dot = shift;
+ my $dir = $self->{HOME};
+ my $file = "$dir/.$dot";
+
+ unless (exists $self->{LIST}->{$dot} || -f $file) {
+ carp "@{[&whowasi]}: no $dot file" if $DEBUG;
+ return undef;
+ }
+
+ if (defined $self->{LIST}->{$dot}) {
+ return $self->{LIST}->{$dot};
+ } else {
+ return $self->{LIST}->{$dot} = `cat $dir/.$dot`;
+ }
+ }
+
+It was easy to write by having it call the Unix cat(1) command, but it
+would probably be more portable to open the file manually (and somewhat
+more efficient). Of course, because dot files are a Unixy concept, we're
+not that concerned.
+
+=item STORE this, key, value
+X<STORE>
+
+This method will be triggered every time an element in the tied hash is set
+(written). It takes two arguments beyond its self reference: the index at
+which we're trying to store something, and the value we're trying to put
+there.
+
+Here in our DotFiles example, we'll be careful not to let
+them try to overwrite the file unless they've called the clobber()
+method on the original object reference returned by tie().
+
+ sub STORE {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ my $dot = shift;
+ my $value = shift;
+ my $file = $self->{HOME} . "/.$dot";
+ my $user = $self->{USER};
+
+ croak "@{[&whowasi]}: $file not clobberable"
+ unless $self->{CLOBBER};
+
+ open(F, "> $file") || croak "can't open $file: $!";
+ print F $value;
+ close(F);
+ }
+
+If they wanted to clobber something, they might say:
+
+ $ob = tie %daemon_dots, 'daemon';
+ $ob->clobber(1);
+ $daemon_dots{signature} = "A true daemon\n";
+
+Another way to lay hands on a reference to the underlying object is to
+use the tied() function, so they might alternately have set clobber
+using:
+
+ tie %daemon_dots, 'daemon';
+ tied(%daemon_dots)->clobber(1);
+
+The clobber method is simply:
+
+ sub clobber {
+ my $self = shift;
+ $self->{CLOBBER} = @_ ? shift : 1;
+ }
+
+=item DELETE this, key
+X<DELETE>
+
+This method is triggered when we remove an element from the hash,
+typically by using the delete() function. Again, we'll
+be careful to check whether they really want to clobber files.
+
+ sub DELETE {
+ carp &whowasi if $DEBUG;
+
+ my $self = shift;
+ my $dot = shift;
+ my $file = $self->{HOME} . "/.$dot";
+ croak "@{[&whowasi]}: won't remove file $file"
+ unless $self->{CLOBBER};
+ delete $self->{LIST}->{$dot};
+ my $success = unlink($file);
+ carp "@{[&whowasi]}: can't unlink $file: $!" unless $success;
+ $success;
+ }
+
+The value returned by DELETE becomes the return value of the call
+to delete(). If you want to emulate the normal behavior of delete(),
+you should return whatever FETCH would have returned for this key.
+In this example, we have chosen instead to return a value which tells
+the caller whether the file was successfully deleted.
+
+=item CLEAR this
+X<CLEAR>
+
+This method is triggered when the whole hash is to be cleared, usually by
+assigning the empty list to it.
+
+In our example, that would remove all the user's dot files! It's such a
+dangerous thing that they'll have to set CLOBBER to something higher than
+1 to make it happen.
+
+ sub CLEAR {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ croak "@{[&whowasi]}: won't remove all dot files for $self->{USER}"
+ unless $self->{CLOBBER} > 1;
+ my $dot;
+ foreach $dot ( keys %{$self->{LIST}}) {
+ $self->DELETE($dot);
+ }
+ }
+
+=item EXISTS this, key
+X<EXISTS>
+
+This method is triggered when the user uses the exists() function
+on a particular hash. In our example, we'll look at the C<{LIST}>
+hash element for this:
+
+ sub EXISTS {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ my $dot = shift;
+ return exists $self->{LIST}->{$dot};
+ }
+
+=item FIRSTKEY this
+X<FIRSTKEY>
+
+This method will be triggered when the user is going
+to iterate through the hash, such as via a keys() or each()
+call.
+
+ sub FIRSTKEY {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ my $a = keys %{$self->{LIST}}; # reset each() iterator
+ each %{$self->{LIST}}
+ }
+
+=item NEXTKEY this, lastkey
+X<NEXTKEY>
+
+This method gets triggered during a keys() or each() iteration. It has a
+second argument which is the last key that had been accessed. This is
+useful if you're carrying about ordering or calling the iterator from more
+than one sequence, or not really storing things in a hash anywhere.
+
+For our example, we're using a real hash so we'll do just the simple
+thing, but we'll have to go through the LIST field indirectly.
+
+ sub NEXTKEY {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ return each %{ $self->{LIST} }
+ }
+
+=item SCALAR this
+X<SCALAR>
+
+This is called when the hash is evaluated in scalar context. In order
+to mimic the behaviour of untied hashes, this method should return a
+false value when the tied hash is considered empty. If this method does
+not exist, perl will make some educated guesses and return true when
+the hash is inside an iteration. If this isn't the case, FIRSTKEY is
+called, and the result will be a false value if FIRSTKEY returns the empty
+list, true otherwise.
+
+However, you should B<not> blindly rely on perl always doing the right
+thing. Particularly, perl will mistakenly return true when you clear the
+hash by repeatedly calling DELETE until it is empty. You are therefore
+advised to supply your own SCALAR method when you want to be absolutely
+sure that your hash behaves nicely in scalar context.
+
+In our example we can just call C<scalar> on the underlying hash
+referenced by C<$self-E<gt>{LIST}>:
+
+ sub SCALAR {
+ carp &whowasi if $DEBUG;
+ my $self = shift;
+ return scalar %{ $self->{LIST} }
+ }
+
+=item UNTIE this
+X<UNTIE>
+
+This is called when C<untie> occurs. See L<The C<untie> Gotcha> below.
+
+=item DESTROY this
+X<DESTROY>
+
+This method is triggered when a tied hash is about to go out of
+scope. You don't really need it unless you're trying to add debugging
+or have auxiliary state to clean up. Here's a very simple function:
+
+ sub DESTROY {
+ carp &whowasi if $DEBUG;
+ }
+
+=back
+
+Note that functions such as keys() and values() may return huge lists
+when used on large objects, like DBM files. You may prefer to use the
+each() function to iterate over such. Example:
+
+ # print out history file offsets
+ use NDBM_File;
+ tie(%HIST, 'NDBM_File', '/usr/lib/news/history', 1, 0);
+ while (($key,$val) = each %HIST) {
+ print $key, ' = ', unpack('L',$val), "\n";
+ }
+ untie(%HIST);
+
+=head2 Tying FileHandles
+X<filehandle, tying>
+
+This is partially implemented now.
+
+A class implementing a tied filehandle should define the following
+methods: TIEHANDLE, at least one of PRINT, PRINTF, WRITE, READLINE, GETC,
+READ, and possibly CLOSE, UNTIE and DESTROY. The class can also provide: BINMODE,
+OPEN, EOF, FILENO, SEEK, TELL - if the corresponding perl operators are
+used on the handle.
+
+When STDERR is tied, its PRINT method will be called to issue warnings
+and error messages. This feature is temporarily disabled during the call,
+which means you can use C<warn()> inside PRINT without starting a recursive
+loop. And just like C<__WARN__> and C<__DIE__> handlers, STDERR's PRINT
+method may be called to report parser errors, so the caveats mentioned under
+L<perlvar/%SIG> apply.
+
+All of this is especially useful when perl is embedded in some other
+program, where output to STDOUT and STDERR may have to be redirected
+in some special way. See nvi and the Apache module for examples.
+
+In our example we're going to create a shouting handle.
+
+ package Shout;
+
+=over 4
+
+=item TIEHANDLE classname, LIST
+X<TIEHANDLE>
+
+This is the constructor for the class. That means it is expected to
+return a blessed reference of some sort. The reference can be used to
+hold some internal information.
+
+ sub TIEHANDLE { print "<shout>\n"; my $i; bless \$i, shift }
+
+=item WRITE this, LIST
+X<WRITE>
+
+This method will be called when the handle is written to via the
+C<syswrite> function.
+
+ sub WRITE {
+ $r = shift;
+ my($buf,$len,$offset) = @_;
+ print "WRITE called, \$buf=$buf, \$len=$len, \$offset=$offset";
+ }
+
+=item PRINT this, LIST
+X<PRINT>
+
+This method will be triggered every time the tied handle is printed to
+with the C<print()> or C<say()> functions. Beyond its self reference
+it also expects the list that was passed to the print function.
+
+ sub PRINT { $r = shift; $$r++; print join($,,map(uc($_),@_)),$\ }
+
+C<say()> acts just like C<print()> except $\ will be localized to C<\n> so
+you need do nothing special to handle C<say()> in C<PRINT()>.
+
+=item PRINTF this, LIST
+X<PRINTF>
+
+This method will be triggered every time the tied handle is printed to
+with the C<printf()> function.
+Beyond its self reference it also expects the format and list that was
+passed to the printf function.
+
+ sub PRINTF {
+ shift;
+ my $fmt = shift;
+ print sprintf($fmt, @_);
+ }
+
+=item READ this, LIST
+X<READ>
+
+This method will be called when the handle is read from via the C<read>
+or C<sysread> functions.
+
+ sub READ {
+ my $self = shift;
+ my $bufref = \$_[0];
+ my(undef,$len,$offset) = @_;
+ print "READ called, \$buf=$bufref, \$len=$len, \$offset=$offset";
+ # add to $$bufref, set $len to number of characters read
+ $len;
+ }
+
+=item READLINE this
+X<READLINE>
+
+This method will be called when the handle is read from via <HANDLE>.
+The method should return undef when there is no more data.
+
+ sub READLINE { $r = shift; "READLINE called $$r times\n"; }
+
+=item GETC this
+X<GETC>
+
+This method will be called when the C<getc> function is called.
+
+ sub GETC { print "Don't GETC, Get Perl"; return "a"; }
+
+=item EOF this
+X<EOF>
+
+This method will be called when the C<eof> function is called.
+
+Starting with Perl 5.12, an additional integer parameter will be passed. It
+will be zero if C<eof> is called without parameter; C<1> if C<eof> is given
+a filehandle as a parameter, e.g. C<eof(FH)>; and C<2> in the very special
+case that the tied filehandle is C<ARGV> and C<eof> is called with an empty
+parameter list, e.g. C<eof()>.
+
+ sub EOF { not length $stringbuf }
+
+=item CLOSE this
+X<CLOSE>
+
+This method will be called when the handle is closed via the C<close>
+function.
+
+ sub CLOSE { print "CLOSE called.\n" }
+
+=item UNTIE this
+X<UNTIE>
+
+As with the other types of ties, this method will be called when C<untie> happens.
+It may be appropriate to "auto CLOSE" when this occurs. See
+L<The C<untie> Gotcha> below.
+
+=item DESTROY this
+X<DESTROY>
+
+As with the other types of ties, this method will be called when the
+tied handle is about to be destroyed. This is useful for debugging and
+possibly cleaning up.
+
+ sub DESTROY { print "</shout>\n" }
+
+=back
+
+Here's how to use our little example:
+
+ tie(*FOO,'Shout');
+ print FOO "hello\n";
+ $a = 4; $b = 6;
+ print FOO $a, " plus ", $b, " equals ", $a + $b, "\n";
+ print <FOO>;
+
+=head2 UNTIE this
+X<UNTIE>
+
+You can define for all tie types an UNTIE method that will be called
+at untie(). See L<The C<untie> Gotcha> below.
+
+=head2 The C<untie> Gotcha
+X<untie>
+
+If you intend making use of the object returned from either tie() or
+tied(), and if the tie's target class defines a destructor, there is a
+subtle gotcha you I<must> guard against.
+
+As setup, consider this (admittedly rather contrived) example of a
+tie; all it does is use a file to keep a log of the values assigned to
+a scalar.
+
+ package Remember;
+
+ use strict;
+ use warnings;
+ use IO::File;
+
+ sub TIESCALAR {
+ my $class = shift;
+ my $filename = shift;
+ my $handle = IO::File->new( "> $filename" )
+ or die "Cannot open $filename: $!\n";
+
+ print $handle "The Start\n";
+ bless {FH => $handle, Value => 0}, $class;
+ }
+
+ sub FETCH {
+ my $self = shift;
+ return $self->{Value};
+ }
+
+ sub STORE {
+ my $self = shift;
+ my $value = shift;
+ my $handle = $self->{FH};
+ print $handle "$value\n";
+ $self->{Value} = $value;
+ }
+
+ sub DESTROY {
+ my $self = shift;
+ my $handle = $self->{FH};
+ print $handle "The End\n";
+ close $handle;
+ }
+
+ 1;
+
+Here is an example that makes use of this tie:
+
+ use strict;
+ use Remember;
+
+ my $fred;
+ tie $fred, 'Remember', 'myfile.txt';
+ $fred = 1;
+ $fred = 4;
+ $fred = 5;
+ untie $fred;
+ system "cat myfile.txt";
+
+This is the output when it is executed:
+
+ The Start
+ 1
+ 4
+ 5
+ The End
+
+So far so good. Those of you who have been paying attention will have
+spotted that the tied object hasn't been used so far. So lets add an
+extra method to the Remember class to allow comments to be included in
+the file; say, something like this:
+
+ sub comment {
+ my $self = shift;
+ my $text = shift;
+ my $handle = $self->{FH};
+ print $handle $text, "\n";
+ }
+
+And here is the previous example modified to use the C<comment> method
+(which requires the tied object):
+
+ use strict;
+ use Remember;
+
+ my ($fred, $x);
+ $x = tie $fred, 'Remember', 'myfile.txt';
+ $fred = 1;
+ $fred = 4;
+ comment $x "changing...";
+ $fred = 5;
+ untie $fred;
+ system "cat myfile.txt";
+
+When this code is executed there is no output. Here's why:
+
+When a variable is tied, it is associated with the object which is the
+return value of the TIESCALAR, TIEARRAY, or TIEHASH function. This
+object normally has only one reference, namely, the implicit reference
+from the tied variable. When untie() is called, that reference is
+destroyed. Then, as in the first example above, the object's
+destructor (DESTROY) is called, which is normal for objects that have
+no more valid references; and thus the file is closed.
+
+In the second example, however, we have stored another reference to
+the tied object in $x. That means that when untie() gets called
+there will still be a valid reference to the object in existence, so
+the destructor is not called at that time, and thus the file is not
+closed. The reason there is no output is because the file buffers
+have not been flushed to disk.
+
+Now that you know what the problem is, what can you do to avoid it?
+Prior to the introduction of the optional UNTIE method the only way
+was the good old C<-w> flag. Which will spot any instances where you call
+untie() and there are still valid references to the tied object. If
+the second script above this near the top C<use warnings 'untie'>
+or was run with the C<-w> flag, Perl prints this
+warning message:
+
+ untie attempted while 1 inner references still exist
+
+To get the script to work properly and silence the warning make sure
+there are no valid references to the tied object I<before> untie() is
+called:
+
+ undef $x;
+ untie $fred;
+
+Now that UNTIE exists the class designer can decide which parts of the
+class functionality are really associated with C<untie> and which with
+the object being destroyed. What makes sense for a given class depends
+on whether the inner references are being kept so that non-tie-related
+methods can be called on the object. But in most cases it probably makes
+sense to move the functionality that would have been in DESTROY to the UNTIE
+method.
+
+If the UNTIE method exists then the warning above does not occur. Instead the
+UNTIE method is passed the count of "extra" references and can issue its own
+warning if appropriate. e.g. to replicate the no UNTIE case this method can
+be used:
+
+ sub UNTIE
+ {
+ my ($obj,$count) = @_;
+ carp "untie attempted while $count inner references still exist" if $count;
+ }
+
+=head1 SEE ALSO
+
+See L<DB_File> or L<Config> for some interesting tie() implementations.
+A good starting point for many tie() implementations is with one of the
+modules L<Tie::Scalar>, L<Tie::Array>, L<Tie::Hash>, or L<Tie::Handle>.
+
+=head1 BUGS
+
+The bucket usage information provided by C<scalar(%hash)> is not
+available. What this means is that using %tied_hash in boolean
+context doesn't work right (currently this always tests false,
+regardless of whether the hash is empty or hash elements).
+
+Localizing tied arrays or hashes does not work. After exiting the
+scope the arrays or the hashes are not restored.
+
+Counting the number of entries in a hash via C<scalar(keys(%hash))>
+or C<scalar(values(%hash)>) is inefficient since it needs to iterate
+through all the entries with FIRSTKEY/NEXTKEY.
+
+Tied hash/array slices cause multiple FETCH/STORE pairs, there are no
+tie methods for slice operations.
+
+You cannot easily tie a multilevel data structure (such as a hash of
+hashes) to a dbm file. The first problem is that all but GDBM and
+Berkeley DB have size limitations, but beyond that, you also have problems
+with how references are to be represented on disk. One
+module that does attempt to address this need is DBM::Deep. Check your
+nearest CPAN site as described in L<perlmodlib> for source code. Note
+that despite its name, DBM::Deep does not use dbm. Another earlier attempt
+at solving the problem is MLDBM, which is also available on the CPAN, but
+which has some fairly serious limitations.
+
+Tied filehandles are still incomplete. sysopen(), truncate(),
+flock(), fcntl(), stat() and -X can't currently be trapped.
+
+=head1 AUTHOR
+
+Tom Christiansen
+
+TIEHANDLE by Sven Verdoolaege <F<skimo@dns.ufsia.ac.be>> and Doug MacEachern <F<dougm@osf.org>>
+
+UNTIE by Nick Ing-Simmons <F<nick@ing-simmons.net>>
+
+SCALAR by Tassilo von Parseval <F<tassilo.von.parseval@rwth-aachen.de>>
+
+Tying Arrays by Casey West <F<casey@geeknest.com>>
diff --git a/Master/tlpkg/tlperl/lib/pods/perltoc.pod b/Master/tlpkg/tlperl/lib/pods/perltoc.pod
new file mode 100644
index 00000000000..f1bd988bf30
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltoc.pod
@@ -0,0 +1,35597 @@
+
+# !!!!!!! DO NOT EDIT THIS FILE !!!!!!!
+# This file is autogenerated by buildtoc from all the other pods.
+# Edit those files and run buildtoc --build-toc to effect changes.
+
+=head1 NAME
+
+perltoc - perl documentation table of contents
+
+=head1 DESCRIPTION
+
+This page provides a brief table of contents for the rest of the Perl
+documentation set. It is meant to be scanned quickly or grepped
+through to locate the proper section you're looking for.
+
+=head1 BASIC DOCUMENTATION
+
+=head2 perl - The Perl language interpreter
+
+=over 4
+
+=item SYNOPSIS
+
+=item GETTING HELP
+
+=over 4
+
+=item Overview
+
+=item Tutorials
+
+=item Reference Manual
+
+=item Internals and C Language Interface
+
+=item Miscellaneous
+
+=item Language-Specific
+
+=item Platform-Specific
+
+=back
+
+=item DESCRIPTION
+
+=item AVAILABILITY
+
+=item ENVIRONMENT
+
+=item AUTHOR
+
+=item FILES
+
+=item SEE ALSO
+
+=item DIAGNOSTICS
+
+=item BUGS
+
+=item NOTES
+
+=back
+
+=head2 perlintro -- a brief introduction and overview of Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item What is Perl?
+
+=item Running Perl programs
+
+=item Safety net
+
+=item Basic syntax overview
+
+=item Perl variable types
+
+Scalars, Arrays, Hashes
+
+=item Variable scoping
+
+=item Conditional and looping constructs
+
+if, while, for, foreach
+
+=item Builtin operators and functions
+
+Arithmetic, Numeric comparison, String comparison, Boolean logic,
+Miscellaneous
+
+=item Files and I/O
+
+=item Regular expressions
+
+Simple matching, Simple substitution, More complex regular expressions,
+Parentheses for capturing, Other regexp features
+
+=item Writing subroutines
+
+=item OO Perl
+
+=item Using Perl modules
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlreftut - Mark's very short tutorial about references
+
+=over 4
+
+=item DESCRIPTION
+
+=item Who Needs Complicated Data Structures?
+
+=item The Solution
+
+=item Syntax
+
+=over 4
+
+=item Making References
+
+=item Using References
+
+=item An Example
+
+=item Arrow Rule
+
+=back
+
+=item Solution
+
+=item The Rest
+
+=item Summary
+
+=item Credits
+
+=over 4
+
+=item Distribution Conditions
+
+=back
+
+=back
+
+=head2 perldsc - Perl Data Structures Cookbook
+
+=over 4
+
+=item DESCRIPTION
+
+arrays of arrays, hashes of arrays, arrays of hashes, hashes of hashes,
+more elaborate constructs
+
+=item REFERENCES
+X<reference> X<dereference> X<dereferencing> X<pointer>
+
+=item COMMON MISTAKES
+
+=item CAVEAT ON PRECEDENCE
+X<dereference, precedence> X<dereferencing, precedence>
+
+=item WHY YOU SHOULD ALWAYS C<use strict>
+
+=item DEBUGGING
+X<data structure, debugging> X<complex data structure, debugging>
+X<AoA, debugging> X<HoA, debugging> X<AoH, debugging> X<HoH, debugging>
+X<array of arrays, debugging> X<hash of arrays, debugging>
+X<array of hashes, debugging> X<hash of hashes, debugging>
+
+=item CODE EXAMPLES
+
+=item ARRAYS OF ARRAYS
+X<array of arrays> X<AoA>
+
+=over 4
+
+=item Declaration of an ARRAY OF ARRAYS
+
+=item Generation of an ARRAY OF ARRAYS
+
+=item Access and Printing of an ARRAY OF ARRAYS
+
+=back
+
+=item HASHES OF ARRAYS
+X<hash of arrays> X<HoA>
+
+=over 4
+
+=item Declaration of a HASH OF ARRAYS
+
+=item Generation of a HASH OF ARRAYS
+
+=item Access and Printing of a HASH OF ARRAYS
+
+=back
+
+=item ARRAYS OF HASHES
+X<array of hashes> X<AoH>
+
+=over 4
+
+=item Declaration of an ARRAY OF HASHES
+
+=item Generation of an ARRAY OF HASHES
+
+=item Access and Printing of an ARRAY OF HASHES
+
+=back
+
+=item HASHES OF HASHES
+X<hash of hashes> X<HoH>
+
+=over 4
+
+=item Declaration of a HASH OF HASHES
+
+=item Generation of a HASH OF HASHES
+
+=item Access and Printing of a HASH OF HASHES
+
+=back
+
+=item MORE ELABORATE RECORDS
+X<record> X<structure> X<struct>
+
+=over 4
+
+=item Declaration of MORE ELABORATE RECORDS
+
+=item Declaration of a HASH OF COMPLEX RECORDS
+
+=item Generation of a HASH OF COMPLEX RECORDS
+
+=back
+
+=item Database Ties
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perllol - Manipulating Arrays of Arrays in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Declaration and Access of Arrays of Arrays
+
+=item Growing Your Own
+
+=item Access and Printing
+
+=item Slices
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perlrequick - Perl regular expressions quick start
+
+=over 4
+
+=item DESCRIPTION
+
+=item The Guide
+
+=over 4
+
+=item Simple word matching
+
+=item Using character classes
+
+=item Matching this or that
+
+=item Grouping things and hierarchical matching
+
+=item Extracting matches
+
+=item Matching repetitions
+
+=item More matching
+
+=item Search and replace
+
+=item The split operator
+
+=back
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHOR AND COPYRIGHT
+
+=over 4
+
+=item Acknowledgments
+
+=back
+
+=back
+
+=head2 perlretut - Perl regular expressions tutorial
+
+=over 4
+
+=item DESCRIPTION
+
+=item Part 1: The basics
+
+=over 4
+
+=item Simple word matching
+
+=item Using character classes
+
+=item Matching this or that
+
+=item Grouping things and hierarchical matching
+
+=item Extracting matches
+
+=item Backreferences
+
+=item Relative backreferences
+
+=item Named backreferences
+
+=item Alternative capture group numbering
+
+=item Position information
+
+=item Non-capturing groupings
+
+=item Matching repetitions
+
+=item Possessive quantifiers
+
+=item Building a regexp
+
+=item Using regular expressions in Perl
+
+=back
+
+=item Part 2: Power tools
+
+=over 4
+
+=item More on characters, strings, and character classes
+
+=item Compiling and saving regular expressions
+
+=item Composing regular expressions at runtime
+
+=item Embedding comments and modifiers in a regular expression
+
+=item Looking ahead and looking behind
+
+=item Using independent subexpressions to prevent backtracking
+
+=item Conditional expressions
+
+=item Defining named patterns
+
+=item Recursive patterns
+
+=item A bit of magic: executing Perl code in a regular expression
+
+=item Backtracking control verbs
+
+=item Pragmas and debugging
+
+=back
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHOR AND COPYRIGHT
+
+=over 4
+
+=item Acknowledgments
+
+=back
+
+=back
+
+=head2 perlboot - Beginner's Object-Oriented Tutorial
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item If we could talk to the animals...
+
+=item Introducing the method invocation arrow
+
+=item Invoking a barnyard
+
+=item The extra parameter of method invocation
+
+=item Calling a second method to simplify things
+
+=item Inheriting the windpipes
+
+=item A few notes about @ISA
+
+=item Overriding the methods
+
+=item Starting the search from a different place
+
+=item The SUPER way of doing things
+
+=item Let's review...
+
+=item A horse is a horse, of course of course, or is it?
+
+=item Invoking an instance method
+
+=item Accessing the instance data
+
+=item How to build a horse
+
+=item Inheriting the constructor
+
+=item Making a method work with either classes or instances
+
+=item Adding parameters to a method
+
+=item More interesting instances
+
+=item A horse of a different color
+
+=item Summary
+
+=back
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 perltoot - Tom's object-oriented tutorial for perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item Creating a Class
+
+=over 4
+
+=item Object Representation
+
+=item Class Interface
+
+=item Constructors and Instance Methods
+
+=item Planning for the Future: Better Constructors
+
+=item Destructors
+
+=item Other Object Methods
+
+=back
+
+=item Class Data
+
+=over 4
+
+=item Accessing Class Data
+
+=item Debugging Methods
+
+=item Class Destructors
+
+=item Documenting the Interface
+
+=back
+
+=item Aggregation
+
+=item Inheritance
+
+=over 4
+
+=item Overridden Methods
+
+=item Multiple Inheritance
+
+=item UNIVERSAL: The Root of All Objects
+
+=item Deeper UNIVERSAL details
+
+=back
+
+=item Alternate Object Representations
+
+=over 4
+
+=item Arrays as Objects
+
+=item Closures as Objects
+
+=back
+
+=item AUTOLOAD: Proxy Methods
+
+=over 4
+
+=item Autoloaded Data Methods
+
+=item Inherited Autoloaded Data Methods
+
+=back
+
+=item Metaclassical Tools
+
+=over 4
+
+=item Class::Struct
+
+=item Data Members as Variables
+
+=back
+
+=item NOTES
+
+=over 4
+
+=item Object Terminology
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR AND COPYRIGHT
+
+=item COPYRIGHT
+
+=over 4
+
+=item Acknowledgments
+
+=back
+
+=back
+
+=head2 perltooc - Tom's OO Tutorial for Class Data in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item Class Data in a Can
+
+=item Class Data as Package Variables
+
+=over 4
+
+=item Putting All Your Eggs in One Basket
+
+=item Inheritance Concerns
+
+=item The Eponymous Meta-Object
+
+=item Indirect References to Class Data
+
+=item Monadic Classes
+
+=item Translucent Attributes
+
+=back
+
+=item Class Data as Lexical Variables
+
+=over 4
+
+=item Privacy and Responsibility
+
+=item File-Scoped Lexicals
+
+=item More Inheritance Concerns
+
+=item Locking the Door and Throwing Away the Key
+
+=item Translucency Revisited
+
+=back
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR AND COPYRIGHT
+
+=item ACKNOWLEDGEMENTS
+
+=item HISTORY
+
+=back
+
+=head2 perlbot - Bag'o Object Tricks (the BOT)
+
+=over 4
+
+=item DESCRIPTION
+
+=item OO SCALING TIPS
+
+=item INSTANCE VARIABLES
+
+=item SCALAR INSTANCE VARIABLES
+
+=item INSTANCE VARIABLE INHERITANCE
+
+=item OBJECT RELATIONSHIPS
+
+=item OVERRIDING SUPERCLASS METHODS
+
+=item USING RELATIONSHIP WITH SDBM
+
+=item THINKING OF CODE REUSE
+
+=item CLASS CONTEXT AND THE OBJECT
+
+=item INHERITING A CONSTRUCTOR
+
+=item DELEGATION
+
+=item SEE ALSO
+
+=back
+
+=head2 perlperf - Perl Performance and Optimization Techniques
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERVIEW
+
+=over 4
+
+=item ONE STEP SIDEWAYS
+
+=item ONE STEP FORWARD
+
+=item ANOTHER STEP SIDEWAYS
+
+=back
+
+=item GENERAL GUIDELINES
+
+=item BENCHMARKS
+
+=over 4
+
+=item Assigning and Dereferencing Variables.
+
+=item Search and replace or tr
+
+=back
+
+=item PROFILING TOOLS
+
+=over 4
+
+=item Devel::DProf
+
+=item Devel::Profiler
+
+=item Devel::SmallProf
+
+=item Devel::FastProf
+
+=item Devel::NYTProf
+
+=back
+
+=item SORTING
+
+Elapsed Real Time, User CPU Time, System CPU Time
+
+=item LOGGING
+
+=over 4
+
+=item Logging if DEBUG (constant)
+
+=back
+
+=item POSTSCRIPT
+
+=item SEE ALSO
+
+=over 4
+
+=item PERLDOCS
+
+=item MAN PAGES
+
+=item MODULES
+
+=item URLS
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlstyle - Perl style guide
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 perlcheat - Perl 5 Cheat Sheet
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item The sheet
+
+=back
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perltrap - Perl traps for the unwary
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Awk Traps
+
+=item C/C++ Traps
+
+=item Sed Traps
+
+=item Shell Traps
+
+=item Perl Traps
+
+=item Perl4 to Perl5 Traps
+
+Discontinuance, Deprecation, and BugFix traps, Parsing Traps, Numerical
+Traps, General data type traps, Context Traps - scalar, list contexts,
+Precedence Traps, General Regular Expression Traps using s///, etc,
+Subroutine, Signal, Sorting Traps, OS Traps, DBM Traps, Unclassified Traps
+
+=item Discontinuance, Deprecation, and BugFix traps
+
+Symbols starting with "_" no longer forced into main, Double-colon valid
+package separator in variable name, 2nd and 3rd args to C<splice()> are now
+in scalar context, Can't do C<goto> into a block that is optimized away,
+Can't use whitespace as variable name or quote delimiter, C<while/if BLOCK
+BLOCK> gone, C<**> binds tighter than unary minus, C<foreach> changed when
+iterating over a list, C<split> with no args behavior changed, B<-e>
+behavior fixed, C<push> returns number of elements in resulting list, Some
+error messages differ, C<split()> honors subroutine args, Bugs removed
+
+=item Parsing Traps
+
+Space between . and = triggers syntax error, Better parsing in perl 5,
+Function parsing, String interpolation of C<$#array> differs, Perl guesses
+on C<map>, C<grep> followed by C<{> if it starts BLOCK or hash ref
+
+=item Numerical Traps
+
+Formatted output and significant digits, Auto-increment operator over
+signed int limit deleted, Assignment of return values from numeric equality
+tests doesn't work, Bitwise string ops
+
+=item General data type traps
+
+Negative array subscripts now count from the end of array, Setting
+C<$#array> lower now discards array elements, Hashes get defined before
+use, Glob assignment from localized variable to variable, Assigning
+C<undef> to glob, Changes in unary negation (of strings), Modifying of
+constants prohibited, C<defined $var> behavior changed, Variable Suicide
+
+=item Context Traps - scalar, list contexts
+
+Elements of argument lists for formats evaluated in list context,
+C<caller()> returns false value in scalar context if no caller present,
+Comma operator in scalar context gives scalar context to args, C<sprintf()>
+prototyped as C<($;@)>
+
+=item Precedence Traps
+
+LHS vs. RHS of any assignment operator, Semantic errors introduced due to
+precedence, Precedence of assignment operators same as the precedence of
+assignment, C<open> requires parentheses around filehandle, C<$:>
+precedence over C<$::> gone, Precedence of file test operators documented,
+C<keys>, C<each>, C<values> are regular named unary operators
+
+=item General Regular Expression Traps using s///, etc.
+
+C<s'$lhs'$rhs'> interpolates on either side, C<m//g> attaches its state to
+the searched string, C<m//o> used within an anonymous sub, C<$+> isn't set
+to whole match, Substitution now returns null string if it fails,
+C<s`lhs`rhs`> is now a normal substitution, Stricter parsing of variables
+in regular expressions, C<m?x?> matches only once, Failed matches don't
+reset the match variables
+
+=item Subroutine, Signal, Sorting Traps
+
+Barewords that used to look like strings look like subroutine calls,
+Reverse is no longer allowed as the name of a sort subroutine, C<warn()>
+won't let you specify a filehandle
+
+=item OS Traps
+
+SysV resets signal handler correctly, SysV C<seek()> appends correctly
+
+=item Interpolation Traps
+
+C<@> always interpolates an array in double-quotish strings, Double-quoted
+strings may no longer end with an unescaped $, Arbitrary expressions are
+evaluated inside braces within double quotes, C<$$x> now tries to
+dereference $x, Creation of hashes on the fly with C<eval "EXPR"> requires
+protection, Bugs in earlier perl versions, Array and hash brackets during
+interpolation, Interpolation of C<\$$foo{bar}>, C<qq()> string passed to
+C<eval> will not find string terminator
+
+=item DBM Traps
+
+Perl5 must have been linked with same dbm/ndbm as the default for
+C<dbmopen()>, DBM exceeding limit on the key/value size will cause perl5 to
+exit immediately
+
+=item Unclassified Traps
+
+C<require>/C<do> trap using returned value, C<split> on empty string with
+LIMIT specified
+
+=back
+
+=back
+
+=head2 perldebtut - Perl debugging tutorial
+
+=over 4
+
+=item DESCRIPTION
+
+=item use strict
+
+=item Looking at data and -w and v
+
+=item help
+
+=item Stepping through code
+
+=item Placeholder for a, w, t, T
+
+=item REGULAR EXPRESSIONS
+
+=item OUTPUT TIPS
+
+=item CGI
+
+=item GUIs
+
+=item SUMMARY
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item CONTRIBUTORS
+
+=back
+
+=head2 perlfaq - frequently asked questions about Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Where to get the perlfaq
+
+=item How to contribute to the perlfaq
+
+=item What will happen if you mail your Perl programming problems to the
+authors?
+
+=back
+
+=item CREDITS
+
+=item AUTHOR AND COPYRIGHT
+
+=item Table of Contents
+
+perlfaq - this document, perlfaq1 - General Questions About Perl, perlfaq2
+- Obtaining and Learning about Perl, perlfaq3 - Programming Tools, perlfaq4
+- Data Manipulation, perlfaq5 - Files and Formats, perlfaq6 - Regular
+Expressions, perlfaq7 - General Perl Language Issues, perlfaq8 - System
+Interaction, perlfaq9 - Networking
+
+=item The Questions
+
+=over 4
+
+=item L<perlfaq1>: General Questions About Perl
+
+=item L<perlfaq2>: Obtaining and Learning about Perl
+
+=item L<perlfaq3>: Programming Tools
+
+=item L<perlfaq4>: Data Manipulation
+
+=item L<perlfaq5>: Files and Formats
+
+=item L<perlfaq6>: Regular Expressions
+
+=item L<perlfaq7>: General Perl Language Issues
+
+=item L<perlfaq8>: System Interaction
+
+=item L<perlfaq9>: Networking
+
+=back
+
+=back
+
+=head2 perlfaq1 - General Questions About Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item What is Perl?
+
+=item Who supports Perl? Who develops it? Why is it free?
+
+=item Which version of Perl should I use?
+
+=item What are Perl 4, Perl 5, or Perl 6?
+
+=item What was Ponie?
+
+=item What is Perl 6?
+
+=item How stable is Perl?
+
+=item Is Perl difficult to learn?
+
+=item How does Perl compare with other languages like Java, Python, REXX,
+Scheme, or Tcl?
+
+=item Can I do [task] in Perl?
+
+=item When shouldn't I program in Perl?
+
+=item What's the difference between "perl" and "Perl"?
+
+=item Is it a Perl program or a Perl script?
+
+=item What is a JAPH?
+
+=item Where can I get a list of Larry Wall witticisms?
+
+=item How can I convince others to use Perl?
+
+http://perltraining.com.au/whyperl.html,
+http://www.perl.org/advocacy/whyperl.html
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq2 - Obtaining and Learning about Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item What machines support perl? Where do I get it?
+
+=item How can I get a binary version of perl?
+
+=item I don't have a C compiler. How can I build my own Perl interpreter?
+
+=item I copied the perl binary from one machine to another, but scripts
+don't work.
+
+=item I grabbed the sources and tried to compile but gdbm/dynamic
+loading/malloc/linking/... failed. How do I make it work?
+
+=item What modules and extensions are available for Perl? What is CPAN?
+What does CPAN/src/... mean?
+
+=item Is there an ISO or ANSI certified version of Perl?
+
+=item Where can I get information on Perl?
+
+=item What are the Perl newsgroups on Usenet? Where do I post questions?
+
+=item Where should I post source code?
+
+=item Perl Books
+
+References, Tutorials, Task-Oriented, Special Topics
+
+=item Which magazines have Perl content?
+
+=item What mailing lists are there for Perl?
+
+=item Where are the archives for comp.lang.perl.misc?
+
+=item Where can I buy a commercial version of perl?
+
+=item Where do I send bug reports?
+
+=item What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq3 - Programming Tools
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item How do I do (anything)?
+
+=item How can I use Perl interactively?
+
+=item Is there a Perl shell?
+
+=item How do I find which modules are installed on my system?
+
+=item How do I debug my Perl programs?
+
+=item How do I profile my Perl programs?
+
+=item How do I cross-reference my Perl programs?
+
+=item Is there a pretty-printer (formatter) for Perl?
+
+=item Is there a ctags for Perl?
+
+=item Is there an IDE or Windows Perl Editor?
+
+Eclipse, Enginsite, Komodo, Notepad++, Open Perl IDE, OptiPerl, Padre,
+PerlBuilder, visiPerl+, Visual Perl, Zeus, GNU Emacs, MicroEMACS, XEmacs,
+Jed, Elvis, Vile, Vim, Codewright, MultiEdit, SlickEdit, ConTEXT, Bash,
+Ksh, Tcsh, Zsh, Affrus, Alpha, BBEdit and BBEdit Lite
+
+=item Where can I get Perl macros for vi?
+
+=item Where can I get perl-mode or cperl-mode for emacs?
+X<emacs>
+
+=item How can I use curses with Perl?
+
+=item How can I write a GUI (X, Tk, Gtk, etc.) in Perl?
+X<GUI> X<Tk> X<Wx> X<WxWidgets> X<Gtk> X<Gtk2> X<CamelBones> X<Qt>
+
+Tk, Wx, Gtk and Gtk2, Win32::GUI, CamelBones, Qt, Athena
+
+=item How can I make my Perl program run faster?
+
+=item How can I make my Perl program take less memory?
+
+Don't slurp!, Use map and grep selectively, Avoid unnecessary quotes and
+stringification, Pass by reference, Tie large variables to disk
+
+=item Is it safe to return a reference to local or lexical data?
+
+=item How can I free an array or hash so my program shrinks?
+
+=item How can I make my CGI script more efficient?
+
+=item How can I hide the source for my Perl program?
+
+=item How can I compile my Perl program into byte code or C?
+
+=item How can I get C<#!perl> to work on [MS-DOS,NT,...]?
+
+=item Can I write useful Perl programs on the command line?
+
+=item Why don't Perl one-liners work on my DOS/Mac/VMS system?
+
+=item Where can I learn about CGI or Web programming in Perl?
+
+=item Where can I learn about object-oriented Perl programming?
+
+=item Where can I learn about linking C with Perl?
+
+=item I've read perlembed, perlguts, etc., but I can't embed perl in my C
+program; what am I doing wrong?
+
+=item When I tried to run my script, I got this message. What does it mean?
+
+=item What's MakeMaker?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq4 - Data Manipulation
+
+=over 4
+
+=item DESCRIPTION
+
+=item Data: Numbers
+
+=over 4
+
+=item Why am I getting long decimals (eg, 19.9499999999999) instead of the
+numbers I should be getting (eg, 19.95)?
+
+=item Why is int() broken?
+
+=item Why isn't my octal data interpreted correctly?
+
+=item Does Perl have a round() function? What about ceil() and floor()?
+Trig functions?
+
+=item How do I convert between numeric representations/bases/radixes?
+
+How do I convert hexadecimal into decimal, How do I convert from decimal to
+hexadecimal, How do I convert from octal to decimal, How do I convert from
+decimal to octal, How do I convert from binary to decimal, How do I convert
+from decimal to binary
+
+=item Why doesn't & work the way I want it to?
+
+=item How do I multiply matrices?
+
+=item How do I perform an operation on a series of integers?
+
+=item How can I output Roman numerals?
+
+=item Why aren't my random numbers random?
+
+=item How do I get a random number between X and Y?
+
+=back
+
+=item Data: Dates
+
+=over 4
+
+=item How do I find the day or week of the year?
+
+=item How do I find the current century or millennium?
+
+=item How can I compare two dates and find the difference?
+
+=item How can I take a string and turn it into epoch seconds?
+
+=item How can I find the Julian Day?
+
+=item How do I find yesterday's date?
+X<date> X<yesterday> X<DateTime> X<Date::Calc> X<Time::Local>
+X<daylight saving time> X<day> X<Today_and_Now> X<localtime>
+X<timelocal>
+
+=item Does Perl have a Year 2000 or 2038 problem? Is Perl Y2K compliant?
+
+=back
+
+=item Data: Strings
+
+=over 4
+
+=item How do I validate input?
+
+=item How do I unescape a string?
+
+=item How do I remove consecutive pairs of characters?
+
+=item How do I expand function calls in a string?
+
+=item How do I find matching/nesting anything?
+
+=item How do I reverse a string?
+
+=item How do I expand tabs in a string?
+
+=item How do I reformat a paragraph?
+
+=item How can I access or change N characters of a string?
+
+=item How do I change the Nth occurrence of something?
+
+=item How can I count the number of occurrences of a substring within a
+string?
+
+=item How do I capitalize all the words on one line?
+X<Text::Autoformat> X<capitalize> X<case, title> X<case, sentence>
+
+=item How can I split a [character] delimited string except when inside
+[character]?
+
+=item How do I strip blank space from the beginning/end of a string?
+
+=item How do I pad a string with blanks or pad a number with zeroes?
+
+=item How do I extract selected columns from a string?
+
+=item How do I find the soundex value of a string?
+
+=item How can I expand variables in text strings?
+
+=item What's wrong with always quoting "$vars"?
+
+=item Why don't my E<lt>E<lt>HERE documents work?
+
+There must be no space after the E<lt>E<lt> part, There (probably) should
+be a semicolon at the end, You can't (easily) have any space in front of
+the tag
+
+=back
+
+=item Data: Arrays
+
+=over 4
+
+=item What is the difference between a list and an array?
+
+=item What is the difference between $array[1] and @array[1]?
+
+=item How can I remove duplicate elements from a list or array?
+
+=item How can I tell whether a certain element is contained in a list or
+array?
+
+=item How do I compute the difference of two arrays? How do I compute the
+intersection of two arrays?
+
+=item How do I test whether two arrays or hashes are equal?
+
+=item How do I find the first array element for which a condition is true?
+
+=item How do I handle linked lists?
+
+=item How do I handle circular lists?
+X<circular> X<array> X<Tie::Cycle> X<Array::Iterator::Circular>
+X<cycle> X<modulus>
+
+=item How do I shuffle an array randomly?
+
+=item How do I process/modify each element of an array?
+
+=item How do I select a random element from an array?
+
+=item How do I permute N elements of a list?
+X<List::Permuter> X<permute> X<Algorithm::Loops> X<Knuth>
+X<The Art of Computer Programming> X<Fischer-Krause>
+
+=item How do I sort an array by (anything)?
+
+=item How do I manipulate arrays of bits?
+
+=item Why does defined() return true on empty arrays and hashes?
+
+=back
+
+=item Data: Hashes (Associative Arrays)
+
+=over 4
+
+=item How do I process an entire hash?
+
+=item How do I merge two hashes?
+X<hash> X<merge> X<slice, hash>
+
+=item What happens if I add or remove keys from a hash while iterating over
+it?
+
+=item How do I look up a hash element by value?
+
+=item How can I know how many entries are in a hash?
+
+=item How do I sort a hash (optionally by value instead of key)?
+
+=item How can I always keep my hash sorted?
+X<hash tie sort DB_File Tie::IxHash>
+
+=item What's the difference between "delete" and "undef" with hashes?
+
+=item Why don't my tied hashes make the defined/exists distinction?
+
+=item How do I reset an each() operation part-way through?
+
+=item How can I get the unique keys from two hashes?
+
+=item How can I store a multidimensional array in a DBM file?
+
+=item How can I make my hash remember the order I put elements into it?
+
+=item Why does passing a subroutine an undefined element in a hash create
+it?
+
+=item How can I make the Perl equivalent of a C structure/C++ class/hash or
+array of hashes or arrays?
+
+=item How can I use a reference as a hash key?
+
+=back
+
+=item Data: Misc
+
+=over 4
+
+=item How do I handle binary data correctly?
+
+=item How do I determine whether a scalar is a number/whole/integer/float?
+
+=item How do I keep persistent data across program calls?
+
+=item How do I print out or copy a recursive data structure?
+
+=item How do I define methods for every class/object?
+
+=item How do I verify a credit card checksum?
+
+=item How do I pack arrays of doubles or floats for XS code?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq5 - Files and Formats
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item How do I flush/unbuffer an output filehandle? Why must I do this?
+X<flush> X<buffer> X<unbuffer> X<autoflush>
+
+=item How do I change, delete, or insert a line in a file, or append to the
+beginning of a file?
+X<file, editing>
+
+=item How do I count the number of lines in a file?
+X<file, counting lines> X<lines> X<line>
+
+=item How do I delete the last N lines from a file?
+X<lines> X<file>
+
+=item How can I use Perl's C<-i> option from within a program?
+X<-i> X<in-place>
+
+=item How can I copy a file?
+X<copy> X<file, copy> X<File::Copy>
+
+=item How do I make a temporary file name?
+X<file, temporary>
+
+=item How can I manipulate fixed-record-length files?
+X<fixed-length> X<file, fixed-length records>
+
+=item How can I make a filehandle local to a subroutine? How do I pass
+filehandles between subroutines? How do I make an array of filehandles?
+X<filehandle, local> X<filehandle, passing> X<filehandle, reference>
+
+=item How can I use a filehandle indirectly?
+X<filehandle, indirect>
+
+=item How can I set up a footer format to be used with write()?
+X<footer>
+
+=item How can I write() into a string?
+X<write, into a string>
+
+=item How can I open a filehandle to a string?
+X<string> X<open> X<IO::String> X<filehandle>
+
+=item How can I output my numbers with commas added?
+X<number, commify>
+
+=item How can I translate tildes (~) in a filename?
+X<tilde> X<tilde expansion>
+
+=item How come when I open a file read-write it wipes it out?
+X<clobber> X<read-write> X<clobbering> X<truncate> X<truncating>
+
+=item Why do I sometimes get an "Argument list too long" when I use
+E<lt>*E<gt>?
+X<argument list too long>
+
+=item Is there a leak/bug in glob()?
+X<glob>
+
+=item How can I open a file with a leading ">" or trailing blanks?
+X<filename, special characters>
+
+=item How can I reliably rename a file?
+X<rename> X<mv> X<move> X<file, rename>
+
+=item How can I lock a file?
+X<lock> X<file, lock> X<flock>
+
+=item Why can't I just open(FH, "E<gt>file.lock")?
+X<lock, lockfile race condition>
+
+=item I still don't get locking. I just want to increment the number in the
+file. How can I do this?
+X<counter> X<file, counter>
+
+=item All I want to do is append a small amount of text to the end of a
+file. Do I still have to use locking?
+X<append> X<file, append>
+
+=item How do I randomly update a binary file?
+X<file, binary patch>
+
+=item How do I get a file's timestamp in perl?
+X<timestamp> X<file, timestamp>
+
+=item How do I set a file's timestamp in perl?
+X<timestamp> X<file, timestamp>
+
+=item How do I print to more than one file at once?
+X<print, to multiple files>
+
+=item How can I read in an entire file all at once?
+X<slurp> X<file, slurping>
+
+=item How can I read in a file by paragraphs?
+X<file, reading by paragraphs>
+
+=item How can I read a single character from a file? From the keyboard?
+X<getc> X<file, reading one character at a time>
+
+=item How can I tell whether there's a character waiting on a filehandle?
+
+=item How do I do a C<tail -f> in perl?
+X<tail> X<IO::Handle> X<File::Tail> X<clearerr>
+
+=item How do I dup() a filehandle in Perl?
+X<dup>
+
+=item How do I close a file descriptor by number?
+X<file, closing file descriptors> X<POSIX> X<close>
+
+=item Why can't I use "C:\temp\foo" in DOS paths? Why doesn't
+`C:\temp\foo.exe` work?
+X<filename, DOS issues>
+
+=item Why doesn't glob("*.*") get all the files?
+X<glob>
+
+=item Why does Perl let me delete read-only files? Why does C<-i> clobber
+protected files? Isn't this a bug in Perl?
+
+=item How do I select a random line from a file?
+X<file, selecting a random line>
+
+=item Why do I get weird spaces when I print an array of lines?
+
+=item How do I traverse a directory tree?
+
+=item How do I delete a directory tree?
+
+=item How do I copy an entire directory?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq6 - Regular Expressions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item How can I hope to use regular expressions without creating illegible
+and unmaintainable code?
+X<regex, legibility> X<regexp, legibility>
+X<regular expression, legibility> X</x>
+
+Comments Outside the Regex, Comments Inside the Regex, Different Delimiters
+
+=item I'm having trouble matching over more than one line. What's wrong?
+X<regex, multiline> X<regexp, multiline> X<regular expression, multiline>
+
+=item How can I pull out lines between two patterns that are themselves on
+different lines?
+X<..>
+
+=item How do I match XML, HTML, or other nasty, ugly things with a regex?
+X<regex, XML> X<regex, HTML> X<XML> X<HTML> X<pain> X<frustration>
+X<sucking out, will to live>
+
+Solve the balanced text problem from another question in L<perlfaq6>, Try
+the recursive regex features in Perl 5.10 and later. See L<perlre>, Try
+defining a grammar using Perl 5.10's C<(?DEFINE)> feature, Break the
+problem down into sub-problems instead of trying to use a single regex,
+Convince everyone not to use XML or HTML in the first place
+
+=item I put a regular expression into $/ but it didn't work. What's wrong?
+X<$/, regexes in> X<$INPUT_RECORD_SEPARATOR, regexes in>
+X<$RS, regexes in>
+
+=item How do I substitute case insensitively on the LHS while preserving
+case on the RHS?
+X<replace, case preserving> X<substitute, case preserving>
+X<substitution, case preserving> X<s, case preserving>
+
+=item How can I make C<\w> match national character sets?
+X<\w>
+
+=item How can I match a locale-smart version of C</[a-zA-Z]/>?
+X<alpha>
+
+=item How can I quote a variable to use in a regex?
+X<regex, escaping> X<regexp, escaping> X<regular expression, escaping>
+
+=item What is C</o> really for?
+X</o, regular expressions> X<compile, regular expressions>
+
+=item How do I use a regular expression to strip C style comments from a
+file?
+
+=item Can I use Perl regular expressions to match balanced text?
+X<regex, matching balanced test> X<regexp, matching balanced test>
+X<regular expression, matching balanced test> X<possessive> X<PARNO>
+X<Text::Balanced> X<Regexp::Common> X<backtracking> X<recursion>
+
+=item What does it mean that regexes are greedy? How can I get around it?
+X<greedy> X<greediness>
+
+=item How do I process each word on each line?
+X<word>
+
+=item How can I print out a word-frequency or line-frequency summary?
+
+=item How can I do approximate matching?
+X<match, approximate> X<matching, approximate>
+
+=item How do I efficiently match many regular expressions at once?
+X<regex, efficiency> X<regexp, efficiency>
+X<regular expression, efficiency>
+
+=item Why don't word-boundary searches with C<\b> work for me?
+X<\b>
+
+=item Why does using $&, $`, or $' slow my program down?
+X<$MATCH> X<$&> X<$POSTMATCH> X<$'> X<$PREMATCH> X<$`>
+
+=item What good is C<\G> in a regular expression?
+X<\G>
+
+=item Are Perl regexes DFAs or NFAs? Are they POSIX compliant?
+X<DFA> X<NFA> X<POSIX>
+
+=item What's wrong with using grep in a void context?
+X<grep>
+
+=item How can I match strings with multibyte characters?
+X<regex, and multibyte characters> X<regexp, and multibyte characters>
+X<regular expression, and multibyte characters> X<martian> X<encoding,
+Martian>
+
+=item How do I match a regular expression that's in a variable?
+X<regex, in variable> X<eval> X<regex> X<quotemeta> X<\Q, regex>
+X<\E, regex>, X<qr//>
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq7 - General Perl Language Issues
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Can I get a BNF/yacc/RE for the Perl language?
+
+=item What are all these $@%&* punctuation signs, and how do I know when to
+use them?
+
+=item Do I always/never have to quote my strings or use semicolons and
+commas?
+
+=item How do I skip some return values?
+
+=item How do I temporarily block warnings?
+
+=item What's an extension?
+
+=item Why do Perl operators have different precedence than C operators?
+
+=item How do I declare/create a structure?
+
+=item How do I create a module?
+
+=item How do I adopt or take over a module already on CPAN?
+
+=item How do I create a class?
+X<class, creation> X<package>
+
+=item How can I tell if a variable is tainted?
+
+=item What's a closure?
+
+=item What is variable suicide and how can I prevent it?
+
+=item How can I pass/return a {Function, FileHandle, Array, Hash, Method,
+Regex}?
+
+Passing Variables and Functions, Passing Filehandles, Passing Regexes,
+Passing Methods
+
+=item How do I create a static variable?
+
+=item What's the difference between dynamic and lexical (static) scoping?
+Between local() and my()?
+
+=item How can I access a dynamic variable while a similarly named lexical
+is in scope?
+
+=item What's the difference between deep and shallow binding?
+
+=item Why doesn't "my($foo) = E<lt>FILEE<gt>;" work right?
+
+=item How do I redefine a builtin function, operator, or method?
+
+=item What's the difference between calling a function as &foo and foo()?
+
+=item How do I create a switch or case statement?
+
+=item How can I catch accesses to undefined variables, functions, or
+methods?
+
+=item Why can't a method included in this same file be found?
+
+=item How can I find out my current or calling package?
+
+=item How can I comment out a large block of Perl code?
+
+=item How do I clear a package?
+
+=item How can I use a variable as a variable name?
+
+=item What does "bad interpreter" mean?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq8 - System Interaction
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item How do I find out which operating system I'm running under?
+
+=item How come exec() doesn't return?
+X<exec> X<system> X<fork> X<open> X<pipe>
+
+=item How do I do fancy stuff with the keyboard/screen/mouse?
+
+Keyboard, Screen, Mouse
+
+=item How do I print something out in color?
+
+=item How do I read just one key without waiting for a return key?
+
+=item How do I check whether input is ready on the keyboard?
+
+=item How do I clear the screen?
+
+=item How do I get the screen size?
+
+=item How do I ask the user for a password?
+
+=item How do I read and write the serial port?
+
+lockfiles, open mode, end of line, flushing output, non-blocking input
+
+=item How do I decode encrypted password files?
+
+=item How do I start a process in the background?
+
+STDIN, STDOUT, and STDERR are shared, Signals, Zombies
+
+=item How do I trap control characters/signals?
+
+=item How do I modify the shadow password file on a Unix system?
+
+=item How do I set the time and date?
+
+=item How can I sleep() or alarm() for under a second?
+X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
+
+=item How can I measure time under a second?
+X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
+
+=item How can I do an atexit() or setjmp()/longjmp()? (Exception handling)
+
+=item Why doesn't my sockets program work under System V (Solaris)? What
+does the error message "Protocol not supported" mean?
+
+=item How can I call my system's unique C functions from Perl?
+
+=item Where do I get the include files to do ioctl() or syscall()?
+
+=item Why do setuid perl scripts complain about kernel problems?
+
+=item How can I open a pipe both to and from a command?
+
+=item Why can't I get the output of a command with system()?
+
+=item How can I capture STDERR from an external command?
+
+=item Why doesn't open() return an error when a pipe open fails?
+
+=item What's wrong with using backticks in a void context?
+
+=item How can I call backticks without shell processing?
+
+=item Why can't my script read from STDIN after I gave it EOF (^D on Unix,
+^Z on MS-DOS)?
+
+=item How can I convert my shell script to perl?
+
+=item Can I use perl to run a telnet or ftp session?
+
+=item How can I write expect in Perl?
+
+=item Is there a way to hide perl's command line from programs such as
+"ps"?
+
+=item I {changed directory, modified my environment} in a perl script. How
+come the change disappeared when I exited the script? How do I get my
+changes to be visible?
+
+Unix
+
+=item How do I close a process's filehandle without waiting for it to
+complete?
+
+=item How do I fork a daemon process?
+
+=item How do I find out if I'm running interactively or not?
+
+=item How do I timeout a slow event?
+
+=item How do I set CPU limits?
+X<BSD::Resource> X<limit> X<CPU>
+
+=item How do I avoid zombies on a Unix system?
+
+=item How do I use an SQL database?
+
+=item How do I make a system() exit on control-C?
+
+=item How do I open a file without blocking?
+
+=item How do I tell the difference between errors from the shell and perl?
+
+=item How do I install a module from CPAN?
+
+=item What's the difference between require and use?
+
+=item How do I keep my own module/library directory?
+
+=item How do I add the directory my program lives in to the module/library
+search path?
+
+=item How do I add a directory to my include path (@INC) at runtime?
+
+the C<PERLLIB> environment variable, the C<PERL5LIB> environment variable,
+the C<perl -Idir> command line flag, the C<lib> pragma:, the C<local::lib>
+module:
+
+=item What is socket.ph and where do I get it?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlfaq9 - Networking
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item What is the correct form of response from a CGI script?
+
+=item My CGI script runs from the command line but not the browser. (500
+Server Error)
+
+=item How can I get better error messages from a CGI program?
+
+=item How do I remove HTML from a string?
+
+=item How do I extract URLs?
+
+=item How do I download a file from the user's machine? How do I open a
+file on another machine?
+
+=item How do I make an HTML pop-up menu with Perl?
+
+=item How do I fetch an HTML file?
+
+=item How do I automate an HTML form submission?
+
+=item How do I decode or create those %-encodings on the web?
+X<URI> X<CGI.pm> X<CGI> X<URI::Escape> X<RFC 2396>
+
+=item How do I redirect to another page?
+
+=item How do I put a password on my web pages?
+
+=item How do I edit my .htpasswd and .htgroup files with Perl?
+
+=item How do I make sure users can't enter values into a form that cause my
+CGI script to do bad things?
+
+=item How do I parse a mail header?
+
+=item How do I decode a CGI form?
+
+=item How do I check a valid mail address?
+
+=item How do I decode a MIME/BASE64 string?
+
+=item How do I return the user's mail address?
+
+=item How do I send mail?
+
+=item How do I use MIME to make an attachment to a mail message?
+
+=item How do I read mail?
+
+=item How do I find out my hostname, domainname, or IP address?
+X<hostname, domainname, IP address, host, domain, hostfqdn, inet_ntoa,
+gethostbyname, Socket, Net::Domain, Sys::Hostname>
+
+=item How do I fetch a news article or the active newsgroups?
+
+=item How do I fetch/put an FTP file?
+
+=item How can I do RPC in Perl?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlsyn - Perl syntax
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Declarations
+X<declaration> X<undef> X<undefined> X<uninitialized>
+
+=item Comments
+X<comment> X<#>
+
+=item Simple Statements
+X<statement> X<semicolon> X<expression> X<;>
+
+=item Truth and Falsehood
+X<truth> X<falsehood> X<true> X<false> X<!> X<not> X<negation> X<0>
+
+=item Statement Modifiers
+X<statement modifier> X<modifier> X<if> X<unless> X<while>
+X<until> X<when> X<foreach> X<for>
+
+=item Compound Statements
+X<statement, compound> X<block> X<bracket, curly> X<curly bracket> X<brace>
+X<{> X<}> X<if> X<unless> X<while> X<until> X<foreach> X<for> X<continue>
+
+=item Loop Control
+X<loop control> X<loop, control> X<next> X<last> X<redo> X<continue>
+
+=item For Loops
+X<for> X<foreach>
+
+=item Foreach Loops
+X<for> X<foreach>
+
+=item Basic BLOCKs
+X<block>
+
+=item Switch statements
+X<switch> X<case> X<given> X<when> X<default>
+
+=item Goto
+X<goto>
+
+=item PODs: Embedded Documentation
+X<POD> X<documentation>
+
+=item Plain Old Comments (Not!)
+X<comment> X<line> X<#> X<preprocessor> X<eval>
+
+=back
+
+=back
+
+=head2 perldata - Perl data types
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Variable names
+X<variable, name> X<variable name> X<data type> X<type>
+
+=item Context
+X<context> X<scalar context> X<list context>
+
+=item Scalar values
+X<scalar> X<number> X<string> X<reference>
+
+=item Scalar value constructors
+X<scalar, literal> X<scalar, constant>
+
+=item List value constructors
+X<list>
+
+=item Subscripts
+
+=item Slices
+X<slice> X<array, slice> X<hash, slice>
+
+=item Typeglobs and Filehandles
+X<typeglob> X<filehandle> X<*>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlop - Perl operators and precedence
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Operator Precedence and Associativity
+X<operator, precedence> X<precedence> X<associativity>
+
+=item Terms and List Operators (Leftward)
+X<list operator> X<operator, list> X<term>
+
+=item The Arrow Operator
+X<arrow> X<dereference> X<< -> >>
+
+=item Auto-increment and Auto-decrement
+X<increment> X<auto-increment> X<++> X<decrement> X<auto-decrement> X<-->
+
+=item Exponentiation
+X<**> X<exponentiation> X<power>
+
+=item Symbolic Unary Operators
+X<unary operator> X<operator, unary>
+
+=item Binding Operators
+X<binding> X<operator, binding> X<=~> X<!~>
+
+=item Multiplicative Operators
+X<operator, multiplicative>
+
+=item Additive Operators
+X<operator, additive>
+
+=item Shift Operators
+X<shift operator> X<operator, shift> X<<< << >>>
+X<<< >> >>> X<right shift> X<left shift> X<bitwise shift>
+X<shl> X<shr> X<shift, right> X<shift, left>
+
+=item Named Unary Operators
+X<operator, named unary>
+
+=item Relational Operators
+X<relational operator> X<operator, relational>
+
+=item Equality Operators
+X<equality> X<equal> X<equals> X<operator, equality>
+
+=item Bitwise And
+X<operator, bitwise, and> X<bitwise and> X<&>
+
+=item Bitwise Or and Exclusive Or
+X<operator, bitwise, or> X<bitwise or> X<|> X<operator, bitwise, xor>
+X<bitwise xor> X<^>
+
+=item C-style Logical And
+X<&&> X<logical and> X<operator, logical, and>
+
+=item C-style Logical Or
+X<||> X<operator, logical, or>
+
+=item C-style Logical Defined-Or
+X<//> X<operator, logical, defined-or>
+
+=item Range Operators
+X<operator, range> X<range> X<..> X<...>
+
+=item Conditional Operator
+X<operator, conditional> X<operator, ternary> X<ternary> X<?:>
+
+=item Assignment Operators
+X<assignment> X<operator, assignment> X<=> X<**=> X<+=> X<*=> X<&=>
+X<<< <<= >>> X<&&=> X<-=> X</=> X<|=> X<<< >>= >>> X<||=> X<//=> X<.=>
+X<%=> X<^=> X<x=>
+
+=item Comma Operator
+X<comma> X<operator, comma> X<,>
+
+=item Yada Yada Operator
+X<...> X<... operator> X<yada yada operator>
+
+=item List Operators (Rightward)
+X<operator, list, rightward> X<list operator>
+
+=item Logical Not
+X<operator, logical, not> X<not>
+
+=item Logical And
+X<operator, logical, and> X<and>
+
+=item Logical or, Defined or, and Exclusive Or
+X<operator, logical, or> X<operator, logical, xor>
+X<operator, logical, defined or> X<operator, logical, exclusive or>
+X<or> X<xor>
+
+=item C Operators Missing From Perl
+X<operator, missing from perl> X<&> X<*>
+X<typecasting> X<(TYPE)>
+
+unary &, unary *, (TYPE)
+
+=item Quote and Quote-like Operators
+X<operator, quote> X<operator, quote-like> X<q> X<qq> X<qx> X<qw> X<m>
+X<qr> X<s> X<tr> X<'> X<''> X<"> X<""> X<//> X<`> X<``> X<<< << >>>
+X<escape sequence> X<escape>
+
+=item Regexp Quote-Like Operators
+X<operator, regexp>
+
+qr/STRING/msixpo X<qr> X</i> X</m> X</o> X</s> X</x> X</p>,
+m/PATTERN/msixpogc X<m> X<operator, match> X<regexp, options> X<regexp>
+X<regex, options> X<regex> X</m> X</s> X</i> X</x> X</p> X</o> X</g> X</c>,
+/PATTERN/msixpogc, The empty pattern //, Matching in list context, \G
+assertion, ?PATTERN? X<?>, s/PATTERN/REPLACEMENT/msixpogce X<substitute>
+X<substitution> X<replace> X<regexp, replace> X<regexp, substitute> X</m>
+X</s> X</i> X</x> X</p> X</o> X</g> X</c> X</e>
+
+=item Quote-Like Operators
+X<operator, quote-like>
+
+q/STRING/ X<q> X<quote, single> X<'> X<''>, 'STRING', qq/STRING/ X<qq>
+X<quote, double> X<"> X<"">, "STRING", qx/STRING/ X<qx> X<`> X<``>
+X<backtick>, `STRING`, qw/STRING/ X<qw> X<quote, list> X<quote, words>,
+tr/SEARCHLIST/REPLACEMENTLIST/cds X<tr> X<y> X<transliterate> X</c> X</d>
+X</s>, y/SEARCHLIST/REPLACEMENTLIST/cds, <<EOF X<here-doc> X<heredoc>
+X<here-document> X<<< << >>>, Double Quotes, Single Quotes, Backticks
+
+=item Gory details of parsing quoted constructs
+X<quote, gory details>
+
+Finding the end, Interpolation X<interpolation>, C<<<'EOF'>, C<m''>, the
+pattern of C<s'''>, C<''>, C<q//>, C<tr'''>, C<y'''>, the replacement of
+C<s'''>, C<tr///>, C<y///>, C<"">, C<``>, C<qq//>, C<qx//>, C<< <file*glob>
+>>, C<<<"EOF">, the replacement of C<s///>, C<RE> in C<?RE?>, C</RE/>,
+C<m/RE/>, C<s/RE/foo/>,, parsing regular expressions X<regexp, parse>,
+Optimization of regular expressions X<regexp, optimization>
+
+=item I/O Operators
+X<operator, i/o> X<operator, io> X<io> X<while> X<filehandle>
+X<< <> >> X<@ARGV>
+
+=item Constant Folding
+X<constant folding> X<folding>
+
+=item No-ops
+X<no-op> X<nop>
+
+=item Bitwise String Operators
+X<operator, bitwise, string>
+
+=item Integer Arithmetic
+X<integer>
+
+=item Floating-point Arithmetic
+X<floating-point> X<floating point> X<float> X<real>
+
+=item Bigger Numbers
+X<number, arbitrary precision>
+
+=back
+
+=back
+
+=head2 perlsub - Perl subroutines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Private Variables via my()
+X<my> X<variable, lexical> X<lexical> X<lexical variable> X<scope, lexical>
+X<lexical scope> X<attributes, my>
+
+=item Persistent Private Variables
+X<state> X<state variable> X<static> X<variable, persistent> X<variable,
+static> X<closure>
+
+=item Temporary Values via local()
+X<local> X<scope, dynamic> X<dynamic scope> X<variable, local>
+X<variable, temporary>
+
+=item Lvalue subroutines
+X<lvalue> X<subroutine, lvalue>
+
+Lvalue subroutines are EXPERIMENTAL
+
+=item Passing Symbol Table Entries (typeglobs)
+X<typeglob> X<*>
+
+=item When to Still Use local()
+X<local> X<variable, local>
+
+=item Pass by Reference
+X<pass by reference> X<pass-by-reference> X<reference>
+
+=item Prototypes
+X<prototype> X<subroutine, prototype>
+
+=item Constant Functions
+X<constant>
+
+=item Overriding Built-in Functions
+X<built-in> X<override> X<CORE> X<CORE::GLOBAL>
+
+=item Autoloading
+X<autoloading> X<AUTOLOAD>
+
+=item Subroutine Attributes
+X<attribute> X<subroutine, attribute> X<attrs>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlfunc - Perl builtin functions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Perl Functions by Category
+X<function>
+
+Functions for SCALARs or strings X<scalar> X<string> X<character>, Regular
+expressions and pattern matching X<regular expression> X<regex> X<regexp>,
+Numeric functions X<numeric> X<number> X<trigonometric> X<trigonometry>,
+Functions for real @ARRAYs X<array>, Functions for list data X<list>,
+Functions for real %HASHes X<hash>, Input and output functions X<I/O>
+X<input> X<output> X<dbm>, Functions for fixed length data or records,
+Functions for filehandles, files, or directories X<file> X<filehandle>
+X<directory> X<pipe> X<link> X<symlink>, Keywords related to the control
+flow of your Perl program X<control flow>, Keywords related to switch,
+Keywords related to scoping, Miscellaneous functions, Functions for
+processes and process groups X<process> X<pid> X<process id>, Keywords
+related to Perl modules X<module>, Keywords related to classes and
+object-orientation X<object> X<class> X<package>, Low-level socket
+functions X<socket> X<sock>, System V interprocess communication functions
+X<IPC> X<System V> X<semaphore> X<shared memory> X<memory> X<message>,
+Fetching user and group info X<user> X<group> X<password> X<uid> X<gid>
+X<passwd> X</etc/passwd>, Fetching network info X<network> X<protocol>
+X<host> X<hostname> X<IP> X<address> X<service>, Time-related functions
+X<time> X<date>, Functions new in perl5 X<perl5>, Functions obsoleted in
+perl5
+
+=item Portability
+X<portability> X<Unix> X<portable>
+
+=item Alphabetical Listing of Perl Functions
+
+-I<X> FILEHANDLE
+X<-r>X<-w>X<-x>X<-o>X<-R>X<-W>X<-X>X<-O>X<-e>X<-z>X<-s>X<-f>X<-d>X<-l>X<-p>
+X<-S>X<-b>X<-c>X<-t>X<-u>X<-g>X<-k>X<-T>X<-B>X<-M>X<-A>X<-C>, -I<X> EXPR,
+-I<X> DIRHANDLE, -I<X>, abs VALUE X<abs> X<absolute>, abs, accept
+NEWSOCKET,GENERICSOCKET X<accept>, alarm SECONDS X<alarm> X<SIGALRM>
+X<timer>, alarm, atan2 Y,X X<atan2> X<arctangent> X<tan> X<tangent>, bind
+SOCKET,NAME X<bind>, binmode FILEHANDLE, LAYER X<binmode> X<binary> X<text>
+X<DOS> X<Windows>, binmode FILEHANDLE, bless REF,CLASSNAME X<bless>, bless
+REF, break, caller EXPR X<caller> X<call stack> X<stack> X<stack trace>,
+caller, chdir EXPR X<chdir> X<cd> X<directory, change>, chdir FILEHANDLE,
+chdir DIRHANDLE, chdir, chmod LIST X<chmod> X<permission> X<mode>, chomp
+VARIABLE X<chomp> X<INPUT_RECORD_SEPARATOR> X<$/> X<newline> X<eol>, chomp(
+LIST ), chomp, chop VARIABLE X<chop>, chop( LIST ), chop, chown LIST
+X<chown> X<owner> X<user> X<group>, chr NUMBER X<chr> X<character> X<ASCII>
+X<Unicode>, chr, chroot FILENAME X<chroot> X<root>, chroot, close
+FILEHANDLE X<close>, close, closedir DIRHANDLE X<closedir>, connect
+SOCKET,NAME X<connect>, continue BLOCK X<continue>, continue, cos EXPR
+X<cos> X<cosine> X<acos> X<arccosine>, cos, crypt PLAINTEXT,SALT X<crypt>
+X<digest> X<hash> X<salt> X<plaintext> X<password> X<decrypt>
+X<cryptography> X<passwd> X<encrypt>, dbmclose HASH X<dbmclose>, dbmopen
+HASH,DBNAME,MASK X<dbmopen> X<dbm> X<ndbm> X<sdbm> X<gdbm>, defined EXPR
+X<defined> X<undef> X<undefined>, defined, delete EXPR X<delete>, die LIST
+X<die> X<throw> X<exception> X<raise> X<$@> X<abort>, do BLOCK X<do>
+X<block>, do SUBROUTINE(LIST) X<do>, do EXPR X<do>, dump LABEL X<dump>
+X<core> X<undump>, dump, each HASH X<each> X<hash, iterator>, each ARRAY
+X<array, iterator>, eof FILEHANDLE X<eof> X<end of file> X<end-of-file>,
+eof (), eof, eval EXPR X<eval> X<try> X<catch> X<evaluate> X<parse>
+X<execute> X<error, handling> X<exception, handling>, eval BLOCK, eval,
+exec LIST X<exec> X<execute>, exec PROGRAM LIST, exists EXPR X<exists>
+X<autovivification>, exit EXPR X<exit> X<terminate> X<abort>, exit, exp
+EXPR X<exp> X<exponential> X<antilog> X<antilogarithm> X<e>, exp, fcntl
+FILEHANDLE,FUNCTION,SCALAR X<fcntl>, fileno FILEHANDLE X<fileno>, flock
+FILEHANDLE,OPERATION X<flock> X<lock> X<locking>, fork X<fork> X<child>
+X<parent>, format X<format>, formline PICTURE,LIST X<formline>, getc
+FILEHANDLE X<getc> X<getchar> X<character> X<file, read>, getc, getlogin
+X<getlogin> X<login>, getpeername SOCKET X<getpeername> X<peer>, getpgrp
+PID X<getpgrp> X<group>, getppid X<getppid> X<parent> X<pid>, getpriority
+WHICH,WHO X<getpriority> X<priority> X<nice>, getpwnam NAME X<getpwnam>
+X<getgrnam> X<gethostbyname> X<getnetbyname> X<getprotobyname> X<getpwuid>
+X<getgrgid> X<getservbyname> X<gethostbyaddr> X<getnetbyaddr>
+X<getprotobynumber> X<getservbyport> X<getpwent> X<getgrent> X<gethostent>
+X<getnetent> X<getprotoent> X<getservent> X<setpwent> X<setgrent>
+X<sethostent> X<setnetent> X<setprotoent> X<setservent> X<endpwent>
+X<endgrent> X<endhostent> X<endnetent> X<endprotoent> X<endservent>,
+getgrnam NAME, gethostbyname NAME, getnetbyname NAME, getprotobyname NAME,
+getpwuid UID, getgrgid GID, getservbyname NAME,PROTO, gethostbyaddr
+ADDR,ADDRTYPE, getnetbyaddr ADDR,ADDRTYPE, getprotobynumber NUMBER,
+getservbyport PORT,PROTO, getpwent, getgrent, gethostent, getnetent,
+getprotoent, getservent, setpwent, setgrent, sethostent STAYOPEN, setnetent
+STAYOPEN, setprotoent STAYOPEN, setservent STAYOPEN, endpwent, endgrent,
+endhostent, endnetent, endprotoent, endservent, getsockname SOCKET
+X<getsockname>, getsockopt SOCKET,LEVEL,OPTNAME X<getsockopt>, glob EXPR
+X<glob> X<wildcard> X<filename, expansion> X<expand>, glob, gmtime EXPR
+X<gmtime> X<UTC> X<Greenwich>, gmtime, goto LABEL X<goto> X<jump> X<jmp>,
+goto EXPR, goto &NAME, grep BLOCK LIST X<grep>, grep EXPR,LIST, hex EXPR
+X<hex> X<hexadecimal>, hex, import LIST X<import>, index
+STR,SUBSTR,POSITION X<index> X<indexOf> X<InStr>, index STR,SUBSTR, int
+EXPR X<int> X<integer> X<truncate> X<trunc> X<floor>, int, ioctl
+FILEHANDLE,FUNCTION,SCALAR X<ioctl>, join EXPR,LIST X<join>, keys HASH
+X<keys> X<key>, keys ARRAY, kill SIGNAL, LIST X<kill> X<signal>, last LABEL
+X<last> X<break>, last, lc EXPR X<lc> X<lowercase>, lc, If C<use bytes> is
+in effect:, On EBCDIC platforms, On ASCII platforms, Otherwise, If EXPR has
+the UTF8 flag set, Otherwise, if C<use locale> is in effect, Otherwise, if
+C<use feature 'unicode_strings'> is in effect:, Otherwise:, On EBCDIC
+platforms, On ASCII platforms, lcfirst EXPR X<lcfirst> X<lowercase>,
+lcfirst, length EXPR X<length> X<size>, length, link OLDFILE,NEWFILE
+X<link>, listen SOCKET,QUEUESIZE X<listen>, local EXPR X<local>, localtime
+EXPR X<localtime> X<ctime>, localtime, lock THING X<lock>, log EXPR X<log>
+X<logarithm> X<e> X<ln> X<base>, log, lstat EXPR X<lstat>, lstat, m//, map
+BLOCK LIST X<map>, map EXPR,LIST, mkdir FILENAME,MASK X<mkdir> X<md>
+X<directory, create>, mkdir FILENAME, mkdir, msgctl ID,CMD,ARG X<msgctl>,
+msgget KEY,FLAGS X<msgget>, msgrcv ID,VAR,SIZE,TYPE,FLAGS X<msgrcv>, msgsnd
+ID,MSG,FLAGS X<msgsnd>, my EXPR X<my>, my TYPE EXPR, my EXPR : ATTRS, my
+TYPE EXPR : ATTRS, next LABEL X<next> X<continue>, next, no MODULE VERSION
+LIST X<no declarations> X<unimporting>, no MODULE VERSION, no MODULE LIST,
+no MODULE, no VERSION, oct EXPR X<oct> X<octal> X<hex> X<hexadecimal>
+X<binary> X<bin>, oct, open FILEHANDLE,EXPR X<open> X<pipe> X<file, open>
+X<fopen>, open FILEHANDLE,MODE,EXPR, open FILEHANDLE,MODE,EXPR,LIST, open
+FILEHANDLE,MODE,REFERENCE, open FILEHANDLE, opendir DIRHANDLE,EXPR
+X<opendir>, ord EXPR X<ord> X<encoding>, ord, our EXPR X<our> X<global>,
+our TYPE EXPR, our EXPR : ATTRS, our TYPE EXPR : ATTRS, pack TEMPLATE,LIST
+X<pack>, package NAMESPACE VERSION X<package> X<module> X<namespace>
+X<version>, package NAMESPACE, pipe READHANDLE,WRITEHANDLE X<pipe>, pop
+ARRAY X<pop> X<stack>, pop, pos SCALAR X<pos> X<match, position>, pos,
+print FILEHANDLE LIST X<print>, print LIST, print, printf FILEHANDLE
+FORMAT, LIST X<printf>, printf FORMAT, LIST, prototype FUNCTION
+X<prototype>, push ARRAY,LIST X<push> X<stack>, q/STRING/, qq/STRING/,
+qx/STRING/, qw/STRING/, qr/STRING/, quotemeta EXPR X<quotemeta>
+X<metacharacter>, quotemeta, rand EXPR X<rand> X<random>, rand, read
+FILEHANDLE,SCALAR,LENGTH,OFFSET X<read> X<file, read>, read
+FILEHANDLE,SCALAR,LENGTH, readdir DIRHANDLE X<readdir>, readline EXPR,
+readline X<readline> X<gets> X<fgets>, readlink EXPR X<readlink>, readlink,
+readpipe EXPR, readpipe X<readpipe>, recv SOCKET,SCALAR,LENGTH,FLAGS
+X<recv>, redo LABEL X<redo>, redo, ref EXPR X<ref> X<reference>, ref,
+rename OLDNAME,NEWNAME X<rename> X<move> X<mv> X<ren>, require VERSION
+X<require>, require EXPR, require, reset EXPR X<reset>, reset, return EXPR
+X<return>, return, reverse LIST X<reverse> X<rev> X<invert>, rewinddir
+DIRHANDLE X<rewinddir>, rindex STR,SUBSTR,POSITION X<rindex>, rindex
+STR,SUBSTR, rmdir FILENAME X<rmdir> X<rd> X<directory, remove>, rmdir,
+s///, say FILEHANDLE LIST X<say>, say LIST, say, scalar EXPR X<scalar>
+X<context>, seek FILEHANDLE,POSITION,WHENCE X<seek> X<fseek> X<filehandle,
+position>, seekdir DIRHANDLE,POS X<seekdir>, select FILEHANDLE X<select>
+X<filehandle, default>, select, select RBITS,WBITS,EBITS,TIMEOUT X<select>,
+semctl ID,SEMNUM,CMD,ARG X<semctl>, semget KEY,NSEMS,FLAGS X<semget>, semop
+KEY,OPSTRING X<semop>, send SOCKET,MSG,FLAGS,TO X<send>, send
+SOCKET,MSG,FLAGS, setpgrp PID,PGRP X<setpgrp> X<group>, setpriority
+WHICH,WHO,PRIORITY X<setpriority> X<priority> X<nice> X<renice>, setsockopt
+SOCKET,LEVEL,OPTNAME,OPTVAL X<setsockopt>, shift ARRAY X<shift>, shift,
+shmctl ID,CMD,ARG X<shmctl>, shmget KEY,SIZE,FLAGS X<shmget>, shmread
+ID,VAR,POS,SIZE X<shmread> X<shmwrite>, shmwrite ID,STRING,POS,SIZE,
+shutdown SOCKET,HOW X<shutdown>, sin EXPR X<sin> X<sine> X<asin>
+X<arcsine>, sin, sleep EXPR X<sleep> X<pause>, sleep, socket
+SOCKET,DOMAIN,TYPE,PROTOCOL X<socket>, socketpair
+SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL X<socketpair>, sort SUBNAME LIST
+X<sort> X<qsort> X<quicksort> X<mergesort>, sort BLOCK LIST, sort LIST,
+splice ARRAY,OFFSET,LENGTH,LIST X<splice>, splice ARRAY,OFFSET,LENGTH,
+splice ARRAY,OFFSET, splice ARRAY, split /PATTERN/,EXPR,LIMIT X<split>,
+split /PATTERN/,EXPR, split /PATTERN/, split, sprintf FORMAT, LIST
+X<sprintf>, format parameter index, flags, vector flag, (minimum) width,
+precision, or maximum width X<precision>, size, order of arguments, sqrt
+EXPR X<sqrt> X<root> X<square root>, sqrt, srand EXPR X<srand> X<seed>
+X<randseed>, srand, stat FILEHANDLE X<stat> X<file, status> X<ctime>, stat
+EXPR, stat DIRHANDLE, stat, state EXPR X<state>, state TYPE EXPR, state
+EXPR : ATTRS, state TYPE EXPR : ATTRS, study SCALAR X<study>, study, sub
+NAME BLOCK X<sub>, sub NAME (PROTO) BLOCK, sub NAME : ATTRS BLOCK, sub NAME
+(PROTO) : ATTRS BLOCK, substr EXPR,OFFSET,LENGTH,REPLACEMENT X<substr>
+X<substring> X<mid> X<left> X<right>, substr EXPR,OFFSET,LENGTH, substr
+EXPR,OFFSET, symlink OLDFILE,NEWFILE X<symlink> X<link> X<symbolic link>
+X<link, symbolic>, syscall NUMBER, LIST X<syscall> X<system call>, sysopen
+FILEHANDLE,FILENAME,MODE X<sysopen>, sysopen
+FILEHANDLE,FILENAME,MODE,PERMS, sysread FILEHANDLE,SCALAR,LENGTH,OFFSET
+X<sysread>, sysread FILEHANDLE,SCALAR,LENGTH, sysseek
+FILEHANDLE,POSITION,WHENCE X<sysseek> X<lseek>, system LIST X<system>
+X<shell>, system PROGRAM LIST, syswrite FILEHANDLE,SCALAR,LENGTH,OFFSET
+X<syswrite>, syswrite FILEHANDLE,SCALAR,LENGTH, syswrite FILEHANDLE,SCALAR,
+tell FILEHANDLE X<tell>, tell, telldir DIRHANDLE X<telldir>, tie
+VARIABLE,CLASSNAME,LIST X<tie>, tied VARIABLE X<tied>, time X<time>
+X<epoch>, times X<times>, tr///, truncate FILEHANDLE,LENGTH X<truncate>,
+truncate EXPR,LENGTH, uc EXPR X<uc> X<uppercase> X<toupper>, uc, ucfirst
+EXPR X<ucfirst> X<uppercase>, ucfirst, umask EXPR X<umask>, umask, undef
+EXPR X<undef> X<undefine>, undef, unlink LIST X<unlink> X<delete> X<remove>
+X<rm> X<del>, unlink, unpack TEMPLATE,EXPR X<unpack>, unpack TEMPLATE,
+untie VARIABLE X<untie>, unshift ARRAY,LIST X<unshift>, use Module VERSION
+LIST X<use> X<module> X<import>, use Module VERSION, use Module LIST, use
+Module, use VERSION, utime LIST X<utime>, values HASH X<values>, values
+ARRAY, vec EXPR,OFFSET,BITS X<vec> X<bit> X<bit vector>, wait X<wait>,
+waitpid PID,FLAGS X<waitpid>, wantarray X<wantarray> X<context>, warn LIST
+X<warn> X<warning> X<STDERR>, write FILEHANDLE X<write>, write EXPR, write,
+y///
+
+=back
+
+=back
+
+=head2 perlopentut - tutorial on opening things in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item Open E<agrave> la shell
+
+=over 4
+
+=item Simple Opens
+
+=item Indirect Filehandles
+
+=item Pipe Opens
+
+=item The Minus File
+
+=item Mixing Reads and Writes
+
+=item Filters
+
+=back
+
+=item Open E<agrave> la C
+
+=over 4
+
+=item Permissions E<agrave> la mode
+
+=back
+
+=item Obscure Open Tricks
+
+=over 4
+
+=item Re-Opening Files (dups)
+
+=item Dispelling the Dweomer
+
+=item Paths as Opens
+
+=item Single Argument Open
+
+=item Playing with STDIN and STDOUT
+
+=back
+
+=item Other I/O Issues
+
+=over 4
+
+=item Opening Non-File Files
+
+=item Opening Named Pipes
+
+=item Opening Sockets
+
+=item Binary Files
+
+=item File Locking
+
+=item IO Layers
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR and COPYRIGHT
+
+=item HISTORY
+
+=back
+
+=head2 perlpacktut - tutorial on C<pack> and C<unpack>
+
+=over 4
+
+=item DESCRIPTION
+
+=item The Basic Principle
+
+=item Packing Text
+
+=item Packing Numbers
+
+=over 4
+
+=item Integers
+
+=item Unpacking a Stack Frame
+
+=item How to Eat an Egg on a Net
+
+=item Byte-order modifiers
+
+=item Floating point Numbers
+
+=back
+
+=item Exotic Templates
+
+=over 4
+
+=item Bit Strings
+
+=item Uuencoding
+
+=item Doing Sums
+
+=item Unicode
+
+=item Another Portable Binary Encoding
+
+=back
+
+=item Template Grouping
+
+=item Lengths and Widths
+
+=over 4
+
+=item String Lengths
+
+=item Dynamic Templates
+
+=item Counting Repetitions
+
+=item Intel HEX
+
+=back
+
+=item Packing and Unpacking C Structures
+
+=over 4
+
+=item The Alignment Pit
+
+=item Dealing with Endian-ness
+
+=item Alignment, Take 2
+
+=item Alignment, Take 3
+
+=item Pointers for How to Use Them
+
+=back
+
+=item Pack Recipes
+
+=item Funnies Section
+
+=item Authors
+
+=back
+
+=head2 perlpod - the Plain Old Documentation format
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Ordinary Paragraph
+X<POD, ordinary paragraph>
+
+=item Verbatim Paragraph
+X<POD, verbatim paragraph> X<verbatim>
+
+=item Command Paragraph
+X<POD, command>
+
+C<=head1 I<Heading Text>> X<=head1> X<=head2> X<=head3> X<=head4> X<head1>
+X<head2> X<head3> X<head4>, C<=head2 I<Heading Text>>, C<=head3 I<Heading
+Text>>, C<=head4 I<Heading Text>>, C<=over I<indentlevel>> X<=over>
+X<=item> X<=back> X<over> X<item> X<back>, C<=item I<stuff...>>, C<=back>,
+C<=cut> X<=cut> X<cut>, C<=pod> X<=pod> X<pod>, C<=begin I<formatname>>
+X<=begin> X<=end> X<=for> X<begin> X<end> X<for>, C<=end I<formatname>>,
+C<=for I<formatname> I<text...>>, C<=encoding I<encodingname>> X<=encoding>
+X<encoding>
+
+=item Formatting Codes
+X<POD, formatting code> X<formatting code>
+X<POD, interior sequence> X<interior sequence>
+
+C<IE<lt>textE<gt>> -- italic text X<I> X<< IZ<><> >> X<POD, formatting
+code, italic> X<italic>, C<BE<lt>textE<gt>> -- bold text X<B> X<< BZ<><> >>
+X<POD, formatting code, bold> X<bold>, C<CE<lt>codeE<gt>> -- code text X<C>
+X<< CZ<><> >> X<POD, formatting code, code> X<code>, C<LE<lt>nameE<gt>> --
+a hyperlink X<L> X<< LZ<><> >> X<POD, formatting code, hyperlink>
+X<hyperlink>, C<EE<lt>escapeE<gt>> -- a character escape X<E> X<< EZ<><> >>
+X<POD, formatting code, escape> X<escape>, C<FE<lt>filenameE<gt>> -- used
+for filenames X<F> X<< FZ<><> >> X<POD, formatting code, filename>
+X<filename>, C<SE<lt>textE<gt>> -- text contains non-breaking spaces X<S>
+X<< SZ<><> >> X<POD, formatting code, non-breaking space> X<non-breaking
+space>, C<XE<lt>topic nameE<gt>> -- an index entry X<X> X<< XZ<><> >>
+X<POD, formatting code, index entry> X<index entry>, C<ZE<lt>E<gt>> -- a
+null (zero-effect) formatting code X<Z> X<< ZZ<><> >> X<POD, formatting
+code, null> X<null>
+
+=item The Intent
+X<POD, intent of>
+
+=item Embedding Pods in Perl Modules
+X<POD, embedding>
+
+=item Hints for Writing Pod
+
+X<podchecker> X<POD, validating>
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perlpodspec - Plain Old Documentation: format specification and
+notes
+
+=over 4
+
+=item DESCRIPTION
+
+=item Pod Definitions
+
+=item Pod Commands
+
+"=head1", "=head2", "=head3", "=head4", "=pod", "=cut", "=over", "=item",
+"=back", "=begin formatname", "=begin formatname parameter", "=end
+formatname", "=for formatname text...", "=encoding encodingname"
+
+=item Pod Formatting Codes
+
+C<IE<lt>textE<gt>> -- italic text, C<BE<lt>textE<gt>> -- bold text,
+C<CE<lt>codeE<gt>> -- code text, C<FE<lt>filenameE<gt>> -- style for
+filenames, C<XE<lt>topic nameE<gt>> -- an index entry, C<ZE<lt>E<gt>> -- a
+null (zero-effect) formatting code, C<LE<lt>nameE<gt>> -- a hyperlink,
+C<EE<lt>escapeE<gt>> -- a character escape, C<SE<lt>textE<gt>> -- text
+contains non-breaking spaces
+
+=item Notes on Implementing Pod Processors
+
+=item About LE<lt>...E<gt> Codes
+
+First:, Second:, Third:, Fourth:, Fifth:, Sixth:
+
+=item About =over...=back Regions
+
+=item About Data Paragraphs and "=begin/=end" Regions
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perlrun - how to execute the Perl interpreter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item #! and quoting on non-Unix systems
+X<hashbang> X<#!>
+
+OS/2, MS-DOS, Win95/NT, VMS
+
+=item Location of Perl
+X<perl, location of interpreter>
+
+=item Command Switches
+X<perl, command switches> X<command switches>
+
+B<-0>[I<octal/hexadecimal>] X<-0> X<$/>, B<-a> X<-a> X<autosplit>, B<-C
+[I<number/list>]> X<-C>, B<-c> X<-c>, B<-d> X<-d> X<-dt>, B<-dt>,
+B<-d:>I<foo[=bar,baz]> X<-d> X<-dt>, B<-dt:>I<foo[=bar,baz]>,
+B<-D>I<letters> X<-D> X<DEBUGGING> X<-DDEBUGGING>, B<-D>I<number>, B<-e>
+I<commandline> X<-e>, B<-E> I<commandline> X<-E>, B<-f> X<-f>
+X<sitecustomize> X<sitecustomize.pl>, B<-F>I<pattern> X<-F>, B<-h> X<-h>,
+B<-i>[I<extension>] X<-i> X<in-place>, B<-I>I<directory> X<-I> X<@INC>,
+B<-l>[I<octnum>] X<-l> X<$/> X<$\>, B<-m>[B<->]I<module> X<-m> X<-M>,
+B<-M>[B<->]I<module>, B<-M>[B<->]I<'module ...'>,
+B<-[mM]>[B<->]I<module=arg[,arg]...>, B<-n> X<-n>, B<-p> X<-p>, B<-s>
+X<-s>, B<-S> X<-S>, B<-t> X<-t>, B<-T> X<-T>, B<-u> X<-u>, B<-U> X<-U>,
+B<-v> X<-v>, B<-V> X<-V>, B<-V:>I<configvar>, B<-w> X<-w>, B<-W> X<-W>,
+B<-X> X<-X>, B<-x> X<-x>, B<-x>I<directory>
+
+=back
+
+=item ENVIRONMENT
+X<perl, environment variables>
+
+HOME X<HOME>, LOGDIR X<LOGDIR>, PATH X<PATH>, PERL5LIB X<PERL5LIB>,
+PERL5OPT X<PERL5OPT>, PERLIO X<PERLIO>, :bytes X<:bytes>, :crlf X<:crlf>,
+:mmap X<:mmap>, :perlio X<:perlio>, :pop X<:pop>, :raw X<:raw>, :stdio
+X<:stdio>, :unix X<:unix>, :utf8 X<:utf8>, :win32 X<:win32>, PERLIO_DEBUG
+X<PERLIO_DEBUG>, PERLLIB X<PERLLIB>, PERL5DB X<PERL5DB>, PERL5DB_THREADED
+X<PERL5DB_THREADED>, PERL5SHELL (specific to the Win32 port) X<PERL5SHELL>,
+PERL_ALLOW_NON_IFS_LSP (specific to the Win32 port)
+X<PERL_ALLOW_NON_IFS_LSP>, PERL_DEBUG_MSTATS X<PERL_DEBUG_MSTATS>,
+PERL_DESTRUCT_LEVEL X<PERL_DESTRUCT_LEVEL>, PERL_DL_NONLAZY
+X<PERL_DL_NONLAZY>, PERL_ENCODING X<PERL_ENCODING>, PERL_HASH_SEED
+X<PERL_HASH_SEED>, PERL_HASH_SEED_DEBUG X<PERL_HASH_SEED_DEBUG>,
+PERL_MEM_LOG X<PERL_MEM_LOG>, PERL_ROOT (specific to the VMS port)
+X<PERL_ROOT>, PERL_SIGNALS X<PERL_SIGNALS>, PERL_UNICODE X<PERL_UNICODE>,
+SYS$LOGIN (specific to the VMS port) X<SYS$LOGIN>
+
+=back
+
+=head2 perldiag - various Perl diagnostics
+
+=over 4
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 perllexwarn - Perl Lexical Warnings
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Default Warnings and Optional Warnings
+
+=item What's wrong with B<-w> and C<$^W>
+
+=item Controlling Warnings from the Command Line
+
+B<-w> X<-w>, B<-W> X<-W>, B<-X> X<-X>
+
+=item Backward Compatibility
+
+=item Category Hierarchy
+X<warning, categories>
+
+=item Fatal Warnings
+X<warning, fatal>
+
+=item Reporting Warnings from a Module
+X<warning, reporting> X<warning, registering>
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perldebug - Perl debugging
+
+=over 4
+
+=item DESCRIPTION
+
+=item The Perl Debugger
+
+=over 4
+
+=item Calling the debugger
+
+perl -d program_name, perl -d -e 0, perl -d:Ptkdb program_name, perl -dt
+threaded_program_name
+
+=item Debugger Commands
+
+h X<debugger command, h>, h [command], h h, p expr X<debugger command, p>,
+x [maxdepth] expr X<debugger command, x>, V [pkg [vars]] X<debugger
+command, V>, X [vars] X<debugger command, X>, y [level [vars]] X<debugger
+command, y>, T X<debugger command, T> X<backtrace> X<stack, backtrace>, s
+[expr] X<debugger command, s> X<step>, n [expr] X<debugger command, n>, r
+X<debugger command, r>, <CR>, c [line|sub] X<debugger command, c>, l
+X<debugger command, l>, l min+incr, l min-max, l line, l subname, -
+X<debugger command, ->, v [line] X<debugger command, v>, . X<debugger
+command, .>, f filename X<debugger command, f>, /pattern/, ?pattern?, L
+[abw] X<debugger command, L>, S [[!]regex] X<debugger command, S>, t
+X<debugger command, t>, t expr X<debugger command, t>, b X<breakpoint>
+X<debugger command, b>, b [line] [condition] X<breakpoint> X<debugger
+command, b>, b subname [condition] X<breakpoint> X<debugger command, b>, b
+postpone subname [condition] X<breakpoint> X<debugger command, b>, b load
+filename X<breakpoint> X<debugger command, b>, b compile subname
+X<breakpoint> X<debugger command, b>, B line X<breakpoint> X<debugger
+command, B>, B * X<breakpoint> X<debugger command, B>, a [line] command
+X<debugger command, a>, A line X<debugger command, A>, A * X<debugger
+command, A>, w expr X<debugger command, w>, W expr X<debugger command, W>,
+W * X<debugger command, W>, o X<debugger command, o>, o booloption ...
+X<debugger command, o>, o anyoption? ... X<debugger command, o>, o
+option=value ... X<debugger command, o>, < ? X<< debugger command, < >>, <
+[ command ] X<< debugger command, < >>, < * X<< debugger command, < >>, <<
+command X<< debugger command, << >>, > ? X<< debugger command, > >>, >
+command X<< debugger command, > >>, > * X<< debugger command, > >>, >>
+command X<<< debugger command, >> >>>, { ? X<debugger command, {>, { [
+command ], { * X<debugger command, {>, {{ command X<debugger command, {{>,
+! number X<debugger command, !>, ! -number X<debugger command, !>, !
+pattern X<debugger command, !>, !! cmd X<debugger command, !!>, source file
+X<debugger command, source>, H -number X<debugger command, H>, q or ^D
+X<debugger command, q> X<debugger command, ^D>, R X<debugger command, R>,
+|dbcmd X<debugger command, |>, ||dbcmd X<debugger command, ||>, command, m
+expr X<debugger command, m>, M X<debugger command, M>, man [manpage]
+X<debugger command, man>
+
+=item Configurable Options
+
+C<recallCommand>, C<ShellBang> X<debugger option, recallCommand> X<debugger
+option, ShellBang>, C<pager> X<debugger option, pager>, C<tkRunning>
+X<debugger option, tkRunning>, C<signalLevel>, C<warnLevel>, C<dieLevel>
+X<debugger option, signalLevel> X<debugger option, warnLevel> X<debugger
+option, dieLevel>, C<AutoTrace> X<debugger option, AutoTrace>, C<LineInfo>
+X<debugger option, LineInfo>, C<inhibit_exit> X<debugger option,
+inhibit_exit>, C<PrintRet> X<debugger option, PrintRet>, C<ornaments>
+X<debugger option, ornaments>, C<frame> X<debugger option, frame>,
+C<maxTraceLen> X<debugger option, maxTraceLen>, C<windowSize> X<debugger
+option, windowSize>, C<arrayDepth>, C<hashDepth> X<debugger option,
+arrayDepth> X<debugger option, hashDepth>, C<dumpDepth> X<debugger option,
+dumpDepth>, C<compactDump>, C<veryCompact> X<debugger option, compactDump>
+X<debugger option, veryCompact>, C<globPrint> X<debugger option,
+globPrint>, C<DumpDBFiles> X<debugger option, DumpDBFiles>, C<DumpPackages>
+X<debugger option, DumpPackages>, C<DumpReused> X<debugger option,
+DumpReused>, C<quote>, C<HighBit>, C<undefPrint> X<debugger option, quote>
+X<debugger option, HighBit> X<debugger option, undefPrint>, C<UsageOnly>
+X<debugger option, UsageOnly>, C<TTY> X<debugger option, TTY>, C<noTTY>
+X<debugger option, noTTY>, C<ReadLine> X<debugger option, ReadLine>,
+C<NonStop> X<debugger option, NonStop>
+
+=item Debugger input/output
+
+Prompt, Multiline commands, Stack backtrace X<backtrace> X<stack,
+backtrace>, Line Listing Format, Frame listing
+
+=item Debugging compile-time statements
+
+=item Debugger Customization
+
+=item Readline Support / History in the debugger
+
+=item Editor Support for Debugging
+
+=item The Perl Profiler
+X<profile> X<profiling> X<profiler>
+
+=back
+
+=item Debugging regular expressions
+X<regular expression, debugging>
+X<regex, debugging> X<regexp, debugging>
+
+=item Debugging memory usage
+X<memory usage>
+
+=item SEE ALSO
+
+=item BUGS
+
+=back
+
+=head2 perlvar - Perl predefined variables
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Predefined Names
+
+$ARG, $_ X<$_> X<$ARG>, $a, $b X<$a> X<$b>, $<I<digits>> ($1, $2, ...)
+X<$1> X<$2> X<$3>, $MATCH, $& X<$&> X<$MATCH>, ${^MATCH} X<${^MATCH}>,
+$PREMATCH, $` X<$`> X<$PREMATCH>, ${^PREMATCH} X<${^PREMATCH}>, $POSTMATCH,
+$' X<$'> X<$POSTMATCH>, ${^POSTMATCH} X<${^POSTMATCH}>, $LAST_PAREN_MATCH,
+$+ X<$+> X<$LAST_PAREN_MATCH>, $LAST_SUBMATCH_RESULT, $^N X<$^N>,
+@LAST_MATCH_END, @+ X<@+> X<@LAST_MATCH_END>, %LAST_PAREN_MATCH, %+ X<%+>,
+HANDLE->input_line_number(EXPR), $INPUT_LINE_NUMBER, $NR, $. X<$.> X<$NR>
+X<$INPUT_LINE_NUMBER> X<line number>,
+IO::Handle->input_record_separator(EXPR), $INPUT_RECORD_SEPARATOR, $RS, $/
+X<$/> X<$RS> X<$INPUT_RECORD_SEPARATOR>, HANDLE->autoflush(EXPR),
+$OUTPUT_AUTOFLUSH, $| X<$|> X<autoflush> X<flush> X<$OUTPUT_AUTOFLUSH>,
+IO::Handle->output_field_separator EXPR, $OUTPUT_FIELD_SEPARATOR, $OFS, $,
+X<$,> X<$OFS> X<$OUTPUT_FIELD_SEPARATOR>,
+IO::Handle->output_record_separator EXPR, $OUTPUT_RECORD_SEPARATOR, $ORS,
+$\ X<$\> X<$ORS> X<$OUTPUT_RECORD_SEPARATOR>, $LIST_SEPARATOR, $" X<$">
+X<$LIST_SEPARATOR>, $SUBSCRIPT_SEPARATOR, $SUBSEP, $; X<$;> X<$SUBSEP>
+X<SUBSCRIPT_SEPARATOR>, HANDLE->format_page_number(EXPR),
+$FORMAT_PAGE_NUMBER, $% X<$%> X<$FORMAT_PAGE_NUMBER>,
+HANDLE->format_lines_per_page(EXPR), $FORMAT_LINES_PER_PAGE, $= X<$=>
+X<$FORMAT_LINES_PER_PAGE>, HANDLE->format_lines_left(EXPR),
+$FORMAT_LINES_LEFT, $- X<$-> X<$FORMAT_LINES_LEFT>, @LAST_MATCH_START, @-
+X<@-> X<@LAST_MATCH_START>, C<$`> is the same as C<substr($var, 0, $-[0])>,
+C<$&> is the same as C<substr($var, $-[0], $+[0] - $-[0])>, C<$'> is the
+same as C<substr($var, $+[0])>, C<$1> is the same as C<substr($var, $-[1],
+$+[1] - $-[1])>, C<$2> is the same as C<substr($var, $-[2], $+[2] -
+$-[2])>, C<$3> is the same as C<substr($var, $-[3], $+[3] - $-[3])>, %-
+X<%->, HANDLE->format_name(EXPR), $FORMAT_NAME, $~ X<$~> X<$FORMAT_NAME>,
+HANDLE->format_top_name(EXPR), $FORMAT_TOP_NAME, $^ X<$^>
+X<$FORMAT_TOP_NAME>, IO::Handle->format_line_break_characters EXPR,
+$FORMAT_LINE_BREAK_CHARACTERS, $: X<$:> X<FORMAT_LINE_BREAK_CHARACTERS>,
+IO::Handle->format_formfeed EXPR, $FORMAT_FORMFEED, $^L X<$^L>
+X<$FORMAT_FORMFEED>, $ACCUMULATOR, $^A X<$^A> X<$ACCUMULATOR>,
+$CHILD_ERROR, $? X<$?> X<$CHILD_ERROR>, ${^CHILD_ERROR_NATIVE}
+X<$^CHILD_ERROR_NATIVE>, ${^ENCODING} X<$^ENCODING>, $OS_ERROR, $ERRNO, $!
+X<$!> X<$ERRNO> X<$OS_ERROR>, %OS_ERROR, %ERRNO, %! X<%!>,
+$EXTENDED_OS_ERROR, $^E X<$^E> X<$EXTENDED_OS_ERROR>, $EVAL_ERROR, $@ X<$@>
+X<$EVAL_ERROR>, $PROCESS_ID, $PID, $$ X<$$> X<$PID> X<$PROCESS_ID>,
+$REAL_USER_ID, $UID, $< X<< $< >> X<$UID> X<$REAL_USER_ID>,
+$EFFECTIVE_USER_ID, $EUID, $> X<< $> >> X<$EUID> X<$EFFECTIVE_USER_ID>,
+$REAL_GROUP_ID, $GID, $( X<$(> X<$GID> X<$REAL_GROUP_ID>,
+$EFFECTIVE_GROUP_ID, $EGID, $) X<$)> X<$EGID> X<$EFFECTIVE_GROUP_ID>,
+$PROGRAM_NAME, $0 X<$0> X<$PROGRAM_NAME>, $[ X<$[>, $] X<$]>, $COMPILING,
+$^C X<$^C> X<$COMPILING>, $DEBUGGING, $^D X<$^D> X<$DEBUGGING>,
+${^RE_DEBUG_FLAGS}, ${^RE_TRIE_MAXBUF}, $SYSTEM_FD_MAX, $^F X<$^F>
+X<$SYSTEM_FD_MAX>, $^H, %^H, $INPLACE_EDIT, $^I X<$^I> X<$INPLACE_EDIT>,
+$^M X<$^M>, $OSNAME, $^O X<$^O> X<$OSNAME>, ${^OPEN}, $PERLDB, $^P X<$^P>
+X<$PERLDB>, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x100, 0x200,
+0x400, $LAST_REGEXP_CODE_RESULT, $^R X<$^R> X<$LAST_REGEXP_CODE_RESULT>,
+$EXCEPTIONS_BEING_CAUGHT, $^S X<$^S> X<$EXCEPTIONS_BEING_CAUGHT>,
+$BASETIME, $^T X<$^T> X<$BASETIME>, ${^TAINT}, ${^UNICODE}, ${^UTF8CACHE},
+${^UTF8LOCALE}, $PERL_VERSION, $^V X<$^V> X<$PERL_VERSION>, $WARNING, $^W
+X<$^W> X<$WARNING>, ${^WARNING_BITS}, ${^WIN32_SLOPPY_STAT}
+X<sitecustomize> X<sitecustomize.pl>, $EXECUTABLE_NAME, $^X X<$^X>
+X<$EXECUTABLE_NAME>, ARGV X<ARGV>, $ARGV X<$ARGV>, @ARGV X<@ARGV>, ARGVOUT
+X<ARGVOUT>, @F X<@F>, @INC X<@INC>, @ARG, @_ X<@_> X<@ARG>, %INC X<%INC>,
+%ENV, $ENV{expr} X<%ENV>, %SIG, $SIG{expr} X<%SIG>
+
+=item Names that are no longer special
+
+$# X<$#>, $* X<$*>
+
+=item Error Indicators
+X<error> X<exception>
+
+=item Technical Note on the Syntax of Variable Names
+
+=back
+
+=item BUGS
+
+=back
+
+=head2 perlre - Perl regular expressions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Modifiers
+
+m X</m> X<regex, multiline> X<regexp, multiline> X<regular expression,
+multiline>, s X</s> X<regex, single-line> X<regexp, single-line> X<regular
+expression, single-line>, i X</i> X<regex, case-insensitive> X<regexp,
+case-insensitive> X<regular expression, case-insensitive>, x X</x>, p X</p>
+X<regex, preserve> X<regexp, preserve>, g and c X</g> X</c>
+
+=item Regular Expressions
+
+[1], [2], [3], [4], [5], [6], [7]
+
+=item Quoting metacharacters
+
+=item Extended Patterns
+
+C<(?#text)> X<(?#)>, C<(?pimsx-imsx)> X<(?)>, C<(?:pattern)> X<(?:)>,
+C<(?imsx-imsx:pattern)>, C<(?|pattern)> X<(?|)> X<Branch reset>,
+Look-Around Assertions X<look-around assertion> X<lookaround assertion>
+X<look-around> X<lookaround>, C<(?=pattern)> X<(?=)> X<look-ahead,
+positive> X<lookahead, positive>, C<(?!pattern)> X<(?!)> X<look-ahead,
+negative> X<lookahead, negative>, C<(?<=pattern)> C<\K> X<(?<=)>
+X<look-behind, positive> X<lookbehind, positive> X<\K>, C<(?<!pattern)>
+X<(?<!)> X<look-behind, negative> X<lookbehind, negative>,
+C<(?'NAME'pattern)>, C<< (?<NAME>pattern) >> X<< (?<NAME>) >> X<(?'NAME')>
+X<named capture> X<capture>, C<< \k<NAME> >>, C<< \k'NAME' >>, C<(?{ code
+})> X<(?{})> X<regex, code in> X<regexp, code in> X<regular expression,
+code in>, C<(??{ code })> X<(??{})> X<regex, postponed> X<regexp,
+postponed> X<regular expression, postponed>, C<(?PARNO)> C<(?-PARNO)>
+C<(?+PARNO)> C<(?R)> C<(?0)> X<(?PARNO)> X<(?1)> X<(?R)> X<(?0)> X<(?-1)>
+X<(?+1)> X<(?-PARNO)> X<(?+PARNO)> X<regex, recursive> X<regexp, recursive>
+X<regular expression, recursive> X<regex, relative recursion>, C<(?&NAME)>
+X<(?&NAME)>, C<(?(condition)yes-pattern|no-pattern)> X<(?()>,
+C<(?(condition)yes-pattern)>, (1) (2) .., (<NAME>) ('NAME'), (?{ CODE }),
+(R), (R1) (R2) .., (R&NAME), (DEFINE), C<< (?>pattern) >> X<backtrack>
+X<backtracking> X<atomic> X<possessive>
+
+=item Special Backtracking Control Verbs
+
+Verbs that take an argument, C<(*PRUNE)> C<(*PRUNE:NAME)> X<(*PRUNE)>
+X<(*PRUNE:NAME)>, C<(*SKIP)> C<(*SKIP:NAME)> X<(*SKIP)>, C<(*MARK:NAME)>
+C<(*:NAME)> X<(*MARK)> C<(*MARK:NAME)> C<(*:NAME)>, C<(*THEN)>
+C<(*THEN:NAME)>, C<(*COMMIT)> X<(*COMMIT)>, Verbs without an argument,
+C<(*FAIL)> C<(*F)> X<(*FAIL)> X<(*F)>, C<(*ACCEPT)> X<(*ACCEPT)>
+
+=item Backtracking
+X<backtrack> X<backtracking>
+
+=item Version 8 Regular Expressions
+X<regular expression, version 8> X<regex, version 8> X<regexp, version 8>
+
+=item Warning on \1 Instead of $1
+
+=item Repeated Patterns Matching a Zero-length Substring
+
+=item Combining RE Pieces
+
+C<ST>, C<S|T>, C<S{REPEAT_COUNT}>, C<S{min,max}>, C<S{min,max}?>, C<S?>,
+C<S*>, C<S+>, C<S??>, C<S*?>, C<S+?>, C<< (?>S) >>, C<(?=S)>, C<(?<=S)>,
+C<(?!S)>, C<(?<!S)>, C<(??{ EXPR })>, C<(?PARNO)>,
+C<(?(condition)yes-pattern|no-pattern)>
+
+=item Creating Custom RE Engines
+
+=back
+
+=item PCRE/Python Support
+
+C<< (?PE<lt>NAMEE<gt>pattern) >>, C<< (?P=NAME) >>, C<< (?P>NAME) >>
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 perlrebackslash - Perl Regular Expression Backslash Sequences and
+Escapes
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item The backslash
+
+[1]
+
+=item All the sequences and escapes
+
+=item Character Escapes
+
+[1], [2]
+
+=item Modifiers
+
+=item Character classes
+
+=item Referencing
+
+=item Assertions
+
+\A, \z, \Z, \G, \b, \B
+
+=item Misc
+
+\C, \K, \N, \R X<\R>, \X X<\X>
+
+=back
+
+=back
+
+=head2 perlrecharclass - Perl Regular Expression Character Classes
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item The dot
+
+=item Backslash sequences
+X<\w> X<\W> X<\s> X<\S> X<\d> X<\D> X<\p> X<\P>
+X<\N> X<\v> X<\V> X<\h> X<\H>
+X<word> X<whitespace>
+
+[1]
+
+=item Bracketed Character Classes
+
+[1], [2], [3], [4], [5] (punct), [6]
+
+=item Locale, EBCDIC, Unicode and UTF-8
+
+=back
+
+=back
+
+=head2 perlreref - Perl Regular Expressions Reference
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item OPERATORS
+
+=item SYNTAX
+
+=item ESCAPE SEQUENCES
+
+=item CHARACTER CLASSES
+
+=item ANCHORS
+
+=item QUANTIFIERS
+
+=item EXTENDED CONSTRUCTS
+
+=item VARIABLES
+
+=item FUNCTIONS
+
+=item TERMINOLOGY
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item THANKS
+
+=back
+
+=head2 perlref - Perl references and nested data structures
+
+=over 4
+
+=item NOTE
+
+=item DESCRIPTION
+
+=over 4
+
+=item Making References
+X<reference, creation> X<referencing>
+
+1. X<\> X<backslash>, 2. X<array, anonymous> X<[> X<[]> X<square bracket>
+X<bracket, square> X<arrayref> X<array reference> X<reference, array>, 3.
+X<hash, anonymous> X<{> X<{}> X<curly bracket> X<bracket, curly> X<brace>
+X<hashref> X<hash reference> X<reference, hash>, 4. X<subroutine,
+anonymous> X<subroutine, reference> X<reference, subroutine> X<scope,
+lexical> X<closure> X<lexical> X<lexical scope>, 5. X<constructor> X<new>,
+6. X<autovivification>, 7. X<*foo{THING}> X<*>
+
+=item Using References
+X<reference, use> X<dereferencing> X<dereference>
+
+=item Symbolic references
+X<reference, symbolic> X<reference, soft>
+X<symbolic reference> X<soft reference>
+
+=item Not-so-symbolic references
+
+=item Pseudo-hashes: Using an array as a hash
+X<pseudo-hash> X<pseudo hash> X<pseudohash>
+
+=item Function Templates
+X<scope, lexical> X<closure> X<lexical> X<lexical scope>
+X<subroutine, nested> X<sub, nested> X<subroutine, local> X<sub, local>
+
+=back
+
+=item WARNING
+X<reference, string context> X<reference, use as hash key>
+
+=item SEE ALSO
+
+=back
+
+=head2 perlform - Perl formats
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Text Fields
+X<format, text field>
+
+=item Numeric Fields
+X<#> X<format, numeric field>
+
+=item The Field @* for Variable Width Multi-Line Text
+X<@*>
+
+=item The Field ^* for Variable Width One-line-at-a-time Text
+X<^*>
+
+=item Specifying Values
+X<format, specifying values>
+
+=item Using Fill Mode
+X<format, fill mode>
+
+=item Suppressing Lines Where All Fields Are Void
+X<format, suppressing lines>
+
+=item Repeating Format Lines
+X<format, repeating lines>
+
+=item Top of Form Processing
+X<format, top of form> X<top> X<header>
+
+=item Format Variables
+X<format variables>
+X<format, variables>
+
+=back
+
+=item NOTES
+
+=over 4
+
+=item Footers
+X<format, footer> X<footer>
+
+=item Accessing Formatting Internals
+X<format, internals>
+
+=back
+
+=item WARNINGS
+
+=back
+
+=head2 perlobj - Perl objects
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item An Object is Simply a Reference
+X<object> X<bless> X<constructor> X<new>
+
+=item A Class is Simply a Package
+X<class> X<package> X<@ISA> X<inheritance>
+
+=item A Method is Simply a Subroutine
+X<method>
+
+=item Method Invocation
+X<invocation> X<method> X<arrow> X<< -> >>
+
+=item Indirect Object Syntax
+X<indirect object syntax> X<invocation, indirect> X<indirect>
+
+=item Default UNIVERSAL methods
+X<UNIVERSAL>
+
+isa(CLASS) X<isa>, DOES(ROLE) X<DOES>, can(METHOD) X<can>, VERSION( [NEED]
+) X<VERSION>
+
+=item Destructors
+X<destructor> X<DESTROY>
+
+=item Summary
+
+=item Two-Phased Garbage Collection
+X<garbage collection> X<GC> X<circular reference>
+X<reference, circular> X<DESTROY> X<destructor>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perltie - how to hide an object class in a simple variable
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Tying Scalars
+X<scalar, tying>
+
+TIESCALAR classname, LIST X<TIESCALAR>, FETCH this X<FETCH>, STORE this,
+value X<STORE>, UNTIE this X<UNTIE>, DESTROY this X<DESTROY>
+
+=item Tying Arrays
+X<array, tying>
+
+TIEARRAY classname, LIST X<TIEARRAY>, FETCH this, index X<FETCH>, STORE
+this, index, value X<STORE>, FETCHSIZE this X<FETCHSIZE>, STORESIZE this,
+count X<STORESIZE>, EXTEND this, count X<EXTEND>, EXISTS this, key
+X<EXISTS>, DELETE this, key X<DELETE>, CLEAR this X<CLEAR>, PUSH this, LIST
+ X<PUSH>, POP this X<POP>, SHIFT this X<SHIFT>, UNSHIFT this, LIST
+X<UNSHIFT>, SPLICE this, offset, length, LIST X<SPLICE>, UNTIE this
+X<UNTIE>, DESTROY this X<DESTROY>
+
+=item Tying Hashes
+X<hash, tying>
+
+USER, HOME, CLOBBER, LIST, TIEHASH classname, LIST X<TIEHASH>, FETCH this,
+key X<FETCH>, STORE this, key, value X<STORE>, DELETE this, key X<DELETE>,
+CLEAR this X<CLEAR>, EXISTS this, key X<EXISTS>, FIRSTKEY this X<FIRSTKEY>,
+NEXTKEY this, lastkey X<NEXTKEY>, SCALAR this X<SCALAR>, UNTIE this
+X<UNTIE>, DESTROY this X<DESTROY>
+
+=item Tying FileHandles
+X<filehandle, tying>
+
+TIEHANDLE classname, LIST X<TIEHANDLE>, WRITE this, LIST X<WRITE>, PRINT
+this, LIST X<PRINT>, PRINTF this, LIST X<PRINTF>, READ this, LIST X<READ>,
+READLINE this X<READLINE>, GETC this X<GETC>, EOF this X<EOF>, CLOSE this
+X<CLOSE>, UNTIE this X<UNTIE>, DESTROY this X<DESTROY>
+
+=item UNTIE this
+X<UNTIE>
+
+=item The C<untie> Gotcha
+X<untie>
+
+=back
+
+=item SEE ALSO
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 perldbmfilter - Perl DBM Filters
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<filter_store_key>, B<filter_store_value>, B<filter_fetch_key>,
+B<filter_fetch_value>
+
+=over 4
+
+=item The Filter
+
+=item An Example: the NULL termination problem.
+
+=item Another Example: Key is a C int.
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perlipc - Perl interprocess communication (signals, fifos, pipes,
+safe subprocesses, sockets, and semaphores)
+
+=over 4
+
+=item DESCRIPTION
+
+=item Signals
+
+=over 4
+
+=item Handling the SIGHUP Signal in Daemons
+
+=back
+
+=item Named Pipes
+
+=over 4
+
+=item Deferred Signals (Safe Signals)
+
+Long-running opcodes, Interrupting IO, Restartable system calls, Signals as
+"faults", Signals triggered by operating system state
+
+=back
+
+=item Using open() for IPC
+
+=over 4
+
+=item Filehandles
+
+=item Background Processes
+
+=item Complete Dissociation of Child from Parent
+
+=item Safe Pipe Opens
+
+=item Avoiding Pipe Deadlocks
+
+=item Bidirectional Communication with Another Process
+
+=item Bidirectional Communication with Yourself
+
+=back
+
+=item Sockets: Client/Server Communication
+
+=over 4
+
+=item Internet Line Terminators
+
+=item Internet TCP Clients and Servers
+
+=item Unix-Domain TCP Clients and Servers
+
+=back
+
+=item TCP Clients with IO::Socket
+
+=over 4
+
+=item A Simple Client
+
+C<Proto>, C<PeerAddr>, C<PeerPort>
+
+=item A Webget Client
+
+=item Interactive Client with IO::Socket
+
+=back
+
+=item TCP Servers with IO::Socket
+
+Proto, LocalPort, Listen, Reuse
+
+=item UDP: Message Passing
+
+=item SysV IPC
+
+=item NOTES
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlfork - Perl's fork() emulation
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Behavior of other Perl features in forked pseudo-processes
+
+$$ or $PROCESS_ID, %ENV, chdir() and all other builtins that accept
+filenames, wait() and waitpid(), kill(), exec(), exit(), Open handles to
+files, directories and network sockets
+
+=item Resource limits
+
+=item Killing the parent process
+
+=item Lifetime of the parent process and pseudo-processes
+
+=item CAVEATS AND LIMITATIONS
+
+BEGIN blocks, Open filehandles, Forking pipe open() not yet implemented,
+Global state maintained by XSUBs, Interpreter embedded in larger
+application, Thread-safety of extensions
+
+=back
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlnumber - semantics of numbers and numeric operations in Perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Storing numbers
+
+=item Numeric operators and numeric conversions
+
+=item Flavors of Perl numeric operations
+
+Arithmetic operators, ++, Arithmetic operators during C<use integer>, Other
+mathematical operators, Bitwise operators, Bitwise operators during C<use
+integer>, Operators which expect an integer, Operators which expect a
+string
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlthrtut - Tutorial on threads in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item What Is A Thread Anyway?
+
+=item Threaded Program Models
+
+=over 4
+
+=item Boss/Worker
+
+=item Work Crew
+
+=item Pipeline
+
+=back
+
+=item What kind of threads are Perl threads?
+
+=item Thread-Safe Modules
+
+=item Thread Basics
+
+=over 4
+
+=item Basic Thread Support
+
+=item A Note about the Examples
+
+=item Creating Threads
+
+=item Waiting For A Thread To Exit
+
+=item Ignoring A Thread
+
+=item Process and Thread Termination
+
+=back
+
+=item Threads And Data
+
+=over 4
+
+=item Shared And Unshared Data
+
+=item Thread Pitfalls: Races
+
+=back
+
+=item Synchronization and control
+
+=over 4
+
+=item Controlling access: lock()
+
+=item A Thread Pitfall: Deadlocks
+
+=item Queues: Passing Data Around
+
+=item Semaphores: Synchronizing Data Access
+
+=item Basic semaphores
+
+=item Advanced Semaphores
+
+=item Waiting for a Condition
+
+=item Giving up control
+
+=back
+
+=item General Thread Utility Routines
+
+=over 4
+
+=item What Thread Am I In?
+
+=item Thread IDs
+
+=item Are These Threads The Same?
+
+=item What Threads Are Running?
+
+=back
+
+=item A Complete Example
+
+=item Different implementations of threads
+
+=item Performance considerations
+
+=item Process-scope Changes
+
+=item Thread-Safety of System Libraries
+
+=item Conclusion
+
+=item SEE ALSO
+
+=item Bibliography
+
+=over 4
+
+=item Introductory Texts
+
+=item OS-Related References
+
+=item Other References
+
+=back
+
+=item Acknowledgements
+
+=item AUTHOR
+
+=item Copyrights
+
+=back
+
+=head2 perlport - Writing portable Perl
+
+=over 4
+
+=item DESCRIPTION
+
+Not all Perl programs have to be portable, Nearly all of Perl already I<is>
+portable
+
+=item ISSUES
+
+=over 4
+
+=item Newlines
+
+=item Numbers endianness and Width
+
+=item Files and Filesystems
+
+=item System Interaction
+
+=item Command names versus file pathnames
+
+=item Networking
+
+=item Interprocess Communication (IPC)
+
+=item External Subroutines (XS)
+
+=item Standard Modules
+
+=item Time and Date
+
+=item Character sets and character encoding
+
+=item Internationalisation
+
+=item System Resources
+
+=item Security
+
+=item Style
+
+=back
+
+=item CPAN Testers
+
+=item PLATFORMS
+
+=over 4
+
+=item Unix
+
+=item DOS and Derivatives
+
+=item VMS
+
+=item VOS
+
+=item EBCDIC Platforms
+
+=item Acorn RISC OS
+
+=item Other perls
+
+=back
+
+=item FUNCTION IMPLEMENTATIONS
+
+=over 4
+
+=item Alphabetical Listing of Perl Functions
+
+-I<X>, alarm, atan2, binmode, chmod, chown, chroot, crypt, dbmclose,
+dbmopen, dump, exec, exit, fcntl, flock, fork, getlogin, getpgrp, getppid,
+getpriority, getpwnam, getgrnam, getnetbyname, getpwuid, getgrgid,
+getnetbyaddr, getprotobynumber, getservbyport, getpwent, getgrent,
+gethostbyname, gethostent, getnetent, getprotoent, getservent, sethostent,
+setnetent, setprotoent, setservent, endpwent, endgrent, endhostent,
+endnetent, endprotoent, endservent, getsockopt SOCKET,LEVEL,OPTNAME, glob,
+gmtime, ioctl FILEHANDLE,FUNCTION,SCALAR, kill, link, localtime, lstat,
+msgctl, msgget, msgsnd, msgrcv, open, readlink, rename, select, semctl,
+semget, semop, setgrent, setpgrp, setpriority, setpwent, setsockopt,
+shmctl, shmget, shmread, shmwrite, sockatmark, socketpair, stat, symlink,
+syscall, sysopen, system, times, truncate, umask, utime, wait, waitpid
+
+=back
+
+=item Supported Platforms
+
+Linux (x86, ARM, IA64), HP-UX, AIX, Win32, Windows 2000, Windows XP,
+Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, Cygwin,
+Solaris (x86, SPARC), OpenVMS, Alpha (7.2 and later), I64 (8.2 and later),
+Symbian, NetBSD, FreeBSD, Haiku, Irix (6.5. What else?), OpenBSD, Dragonfly
+BSD, MirOS BSD, time_t issues that may or may not be fixed, Symbian (Series
+60 v3, 3.2 and 5 - what else?), Stratus VOS / OpenVOS, AIX
+
+=item EOL Platforms (Perl 5.12)
+
+Atari MiNT, Apollo Domain/OS, Apple Mac OS 8/9, Tenon Machten, Windows 95,
+Windows 98, Windows ME, Windows NT4
+
+=item Supported Platforms (Perl 5.8)
+
+=item SEE ALSO
+
+=item AUTHORS / CONTRIBUTORS
+
+=back
+
+=head2 perllocale - Perl locale handling (internationalization and
+localization)
+
+=over 4
+
+=item DESCRIPTION
+
+=item PREPARING TO USE LOCALES
+
+=item USING LOCALES
+
+=over 4
+
+=item The use locale pragma
+
+=item The setlocale function
+
+=item Finding locales
+
+=item LOCALE PROBLEMS
+
+=item Temporarily fixing locale problems
+
+=item Permanently fixing locale problems
+
+=item Permanently fixing your system's locale configuration
+
+=item Fixing system locale configuration
+
+=item The localeconv function
+
+=item I18N::Langinfo
+
+=back
+
+=item LOCALE CATEGORIES
+
+=over 4
+
+=item Category LC_COLLATE: Collation
+
+=item Category LC_CTYPE: Character Types
+
+=item Category LC_NUMERIC: Numeric Formatting
+
+=item Category LC_MONETARY: Formatting of monetary amounts
+
+=item LC_TIME
+
+=item Other categories
+
+=back
+
+=item SECURITY
+
+=item ENVIRONMENT
+
+PERL_BADLANG, LC_ALL, LANGUAGE, LC_CTYPE, LC_COLLATE, LC_MONETARY,
+LC_NUMERIC, LC_TIME, LANG
+
+=over 4
+
+=item Examples
+
+=back
+
+=item NOTES
+
+=over 4
+
+=item Backward compatibility
+
+=item I18N:Collate obsolete
+
+=item Sort speed and memory use impacts
+
+=item write() and LC_NUMERIC
+
+=item Freely available locale definitions
+
+=item I18n and l10n
+
+=item An imperfect standard
+
+=back
+
+=item Unicode and UTF-8
+
+=item BUGS
+
+=over 4
+
+=item Broken systems
+
+=back
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perluniintro - Perl Unicode introduction
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Unicode
+
+=item Perl's Unicode Support
+
+=item Perl's Unicode Model
+
+=item Unicode and EBCDIC
+
+=item Creating Unicode
+
+=item Handling Unicode
+
+=item Legacy Encodings
+
+=item Unicode I/O
+
+=item Displaying Unicode As Text
+
+=item Special Cases
+
+=item Advanced Topics
+
+=item Miscellaneous
+
+=item Questions With Answers
+
+=item Hexadecimal Notation
+
+=item Further Resources
+
+=back
+
+=item UNICODE IN OLDER PERLS
+
+=item SEE ALSO
+
+=item ACKNOWLEDGMENTS
+
+=item AUTHOR, COPYRIGHT, AND LICENSE
+
+=back
+
+=head2 perlunicode - Unicode support in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Important Caveats
+
+Input and Output Layers, Regular Expressions, C<use utf8> still needed to
+enable UTF-8/UTF-EBCDIC in scripts, BOM-marked scripts and UTF-16 scripts
+autodetected, C<use encoding> needed to upgrade non-Latin-1 byte strings
+
+=item Byte and Character Semantics
+
+=item Effects of Character Semantics
+
+=item Unicode Character Properties
+
+B<C<\p{All}>>, B<C<\p{Alnum}>>, B<C<\p{Any}>>, B<C<\p{Assigned}>>,
+B<C<\p{Blank}>>, B<C<\p{Decomposition_Type: Non_Canonical}>> (Short:
+C<\p{Dt=NonCanon}>), B<C<\p{Graph}>>, B<C<\p{HorizSpace}>>, B<C<\p{In=*}>>,
+B<C<\p{PerlSpace}>>, B<C<\p{PerlWord}>>, B<C<\p{PosixAlnum}>>,
+B<C<\p{PosixAlpha}>>, B<C<\p{PosixBlank}>>, B<C<\p{PosixCntrl}>>,
+B<C<\p{PosixDigit}>>, B<C<\p{PosixGraph}>>, B<C<\p{PosixLower}>>,
+B<C<\p{PosixPrint}>>, B<C<\p{PosixPunct}>>, B<C<\p{PosixSpace}>>,
+B<C<\p{PosixUpper}>>, B<C<\p{Present_In: *}>> (Short: C<\p{In=*}>),
+B<C<\p{Print}>>, B<C<\p{SpacePerl}>>, B<C<\p{VertSpace}>>, B<C<\p{Word}>>
+
+=item User-Defined Character Properties
+
+=item User-Defined Case Mappings
+
+=item Character Encodings for Input and Output
+
+=item Unicode Regular Expression Support Level
+
+=item Unicode Encodings
+
+=item Security Implications of Unicode
+
+=item Unicode in Perl on EBCDIC
+
+=item Locales
+
+=item When Unicode Does Not Happen
+
+=item The "Unicode Bug"
+
+=item Forcing Unicode in Perl (Or Unforcing Unicode in Perl)
+
+=item Using Unicode in XS
+
+=item Hacking Perl to work on earlier Unicode versions (for very serious
+hackers only)
+
+=back
+
+=item BUGS
+
+=over 4
+
+=item Interaction with Locales
+
+=item Problems with characters in the Latin-1 Supplement range
+
+=item Problems with case-insensitive regular expression matching
+
+=item Interaction with Extensions
+
+=item Speed
+
+=item Problems on EBCDIC platforms
+
+=item Porting code from perl-5.6.X
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlunifaq - Perl Unicode FAQ
+
+=over 4
+
+=item Q and A
+
+=over 4
+
+=item perlunitut isn't really a Unicode tutorial, is it?
+
+=item What character encodings does Perl support?
+
+=item Which version of perl should I use?
+
+=item What about binary data, like images?
+
+=item When should I decode or encode?
+
+=item What if I don't decode?
+
+=item What if I don't encode?
+
+=item Is there a way to automatically decode or encode?
+
+=item What if I don't know which encoding was used?
+
+=item Can I use Unicode in my Perl sources?
+
+=item Data::Dumper doesn't restore the UTF8 flag; is it broken?
+
+=item Why do regex character classes sometimes match only in the ASCII
+range?
+
+=item Why do some characters not uppercase or lowercase correctly?
+
+=item How can I determine if a string is a text string or a binary string?
+
+=item How do I convert from encoding FOO to encoding BAR?
+
+=item What are C<decode_utf8> and C<encode_utf8>?
+
+=item What is a "wide character"?
+
+=back
+
+=item INTERNALS
+
+=over 4
+
+=item What is "the UTF8 flag"?
+
+=item What about the C<use bytes> pragma?
+
+=item What about the C<use encoding> pragma?
+
+=item What is the difference between C<:encoding> and C<:utf8>?
+
+=item What's the difference between C<UTF-8> and C<utf8>?
+
+=item I lost track; what encoding is the internal format really?
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perluniprops - Index of Unicode Version 5.2.0 properties in Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item Properties accessible through \p{} and \P{}
+
+Single form (\p{name}) tighter rules:, white space adjacent to a non-word
+character, underscores separating digits in numbers, Compound form
+(\p{name=value} or \p{name:value}) tighter rules:, Obsolete, Stabilized,
+Deprecated, B<*> is a wild-card, B<(\d+)> in the info column gives the
+number of code points matched by this property, B<D> means this is
+deprecated, B<O> means this is obsolete, B<S> means this is stabilized,
+B<T> means tighter (stricter) name matching applies, B<X> means use of this
+form is discouraged
+
+=over 4
+
+=item Legal \p{} and \P{} constructs that match no characters
+
+\p{Canonical_Combining_Class=Attached_Below_Left},
+\p{Joining_Type=Left_Joining}
+
+=back
+
+=item Properties not accessible through \p{} and \P{}
+
+=item Unicode regular expression properties that are NOT accepted by Perl
+
+=item Files in the I<To> directory (for serious hackers only)
+
+=item SEE ALSO
+
+=back
+
+=head2 perlunitut - Perl Unicode Tutorial
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Definitions
+
+=item Your new toolkit
+
+=item I/O flow (the actual 5 minute tutorial)
+
+=back
+
+=item SUMMARY
+
+=item Q and A (or FAQ)
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlebcdic - Considerations for running Perl on EBCDIC platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item COMMON CHARACTER CODE SETS
+
+=over 4
+
+=item ASCII
+
+=item ISO 8859
+
+=item Latin 1 (ISO 8859-1)
+
+=item EBCDIC
+
+=item The 13 variant characters
+
+=item 0037
+
+=item 1047
+
+=item POSIX-BC
+
+=item Unicode code points versus EBCDIC code points
+
+=item Remaining Perl Unicode problems in EBCDIC
+
+=item Unicode and UTF
+
+=item Using Encode
+
+=back
+
+=item SINGLE OCTET TABLES
+
+recipe 0, recipe 1, recipe 2, recipe 3, recipe 4, recipe 5, recipe 6
+
+=item IDENTIFYING CHARACTER CODE SETS
+
+=item CONVERSIONS
+
+=over 4
+
+=item tr///
+
+=item iconv
+
+=item C RTL
+
+=back
+
+=item OPERATOR DIFFERENCES
+
+=item FUNCTION DIFFERENCES
+
+chr(), ord(), pack(), print(), printf(), sort(), sprintf(), unpack()
+
+=item REGULAR EXPRESSION DIFFERENCES
+
+=item SOCKETS
+
+=item SORTING
+
+=over 4
+
+=item Ignore ASCII vs. EBCDIC sort differences.
+
+=item MONO CASE then sort data.
+
+=item Convert, sort data, then re convert.
+
+=item Perform sorting on one type of platform only.
+
+=back
+
+=item TRANSFORMATION FORMATS
+
+=over 4
+
+=item URL decoding and encoding
+
+=item uu encoding and decoding
+
+=item Quoted-Printable encoding and decoding
+
+=item Caesarian ciphers
+
+=back
+
+=item Hashing order and checksums
+
+=item I18N AND L10N
+
+=item MULTI OCTET CHARACTER SETS
+
+=item OS ISSUES
+
+=over 4
+
+=item OS/400
+
+PASE, IFS access
+
+=item OS/390, z/OS
+
+chcp, dataset access, OS/390, z/OS iconv, locales
+
+=item VM/ESA?
+
+=item POSIX-BC?
+
+=back
+
+=item BUGS
+
+=item SEE ALSO
+
+=item REFERENCES
+
+=item HISTORY
+
+=item AUTHOR
+
+=back
+
+=head2 perlsec - Perl security
+
+=over 4
+
+=item DESCRIPTION
+
+=item SECURITY VULNERABILITY CONTACT INFORMATION
+
+=item SECURITY MECHANISMS AND CONCERNS
+
+=over 4
+
+=item Taint mode
+
+=item Laundering and Detecting Tainted Data
+
+=item Switches On the "#!" Line
+
+=item Taint mode and @INC
+
+=item Cleaning Up Your Path
+
+=item Security Bugs
+
+=item Protecting Your Programs
+
+=item Unicode
+
+=item Algorithmic Complexity Attacks
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlmod - Perl modules (packages and symbol tables)
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Packages
+X<package> X<namespace> X<variable, global> X<global variable> X<global>
+
+=item Symbol Tables
+X<symbol table> X<stash> X<%::> X<%main::> X<typeglob> X<glob> X<alias>
+
+=item BEGIN, UNITCHECK, CHECK, INIT and END
+X<BEGIN> X<UNITCHECK> X<CHECK> X<INIT> X<END>
+
+=item Perl Classes
+X<class> X<@ISA>
+
+=item Perl Modules
+X<module>
+
+=item Making your module threadsafe
+X<threadsafe> X<thread safe>
+X<module, threadsafe> X<module, thread safe>
+X<CLONE> X<CLONE_SKIP> X<thread> X<threads> X<ithread>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlmodlib - constructing new Perl modules and finding existing ones
+
+=over 4
+
+=item THE PERL MODULE LIBRARY
+
+=over 4
+
+=item Pragmatic Modules
+
+attributes, autodie, autodie::exception, autodie::exception::system,
+autodie::hints, autouse, base, bigint, bignum, bigrat, blib, bytes,
+charnames, constant, deprecate, diagnostics, encoding, encoding::warnings,
+feature, fields, filetest, if, inc::latest, integer, less, lib, locale,
+mro, open, ops, overload, overloading, parent, re, sigtrap, sort, strict,
+subs, threads, threads::shared, utf8, vars, version, vmsish, warnings,
+warnings::register
+
+=item Standard Modules
+
+AnyDBM_File, App::Cpan, App::Prove, App::Prove::State,
+App::Prove::State::Result, App::Prove::State::Result::Test,
+Archive::Extract, Archive::Tar, Archive::Tar::File, Attribute::Handlers,
+AutoLoader, AutoSplit, B, B::Concise, B::Debug, B::Deparse, B::Lint,
+B::Lint::Debug, B::Showlex, B::Terse, B::Xref, Benchmark, CGI, CGI::Apache,
+CGI::Carp, CGI::Cookie, CGI::Fast, CGI::Pretty, CGI::Push, CGI::Switch,
+CGI::Util, CORE, CPAN, CPAN::API::HOWTO, CPAN::Distroprefs,
+CPAN::FirstTime, CPAN::Kwalify, CPAN::Nox, CPAN::Version, CPANPLUS,
+CPANPLUS::Dist::Base, CPANPLUS::Dist::Build,
+CPANPLUS::Dist::Build::Constants, CPANPLUS::Dist::Sample,
+CPANPLUS::Internals::Source::Memory, CPANPLUS::Internals::Source::SQLite,
+CPANPLUS::Shell::Classic, CPANPLUS::Shell::Default::Plugins::HOWTO, Carp,
+Class::ISA, Class::Struct, Compress::Raw::Bzip2, Compress::Raw::Bzip2::FAQ,
+Compress::Raw::Zlib, Compress::Raw::Zlib::FAQ, Compress::Zlib, Config, Cwd,
+DB, DBM_Filter, DBM_Filter::compress, DBM_Filter::encode,
+DBM_Filter::int32, DBM_Filter::null, DBM_Filter::utf8, DB_File,
+Data::Dumper, Devel::DProf, Devel::InnerPackage, Devel::PPPort,
+Devel::Peek, Devel::SelfStubber, Digest, Digest::MD5, Digest::SHA,
+Digest::base, Digest::file, DirHandle, Dumpvalue, DynaLoader, Encode,
+Encode::Alias, Encode::Byte, Encode::CJKConstants, Encode::CN,
+Encode::CN::HZ, Encode::Config, Encode::EBCDIC, Encode::Encoder,
+Encode::Encoding, Encode::GSM0338, Encode::Guess, Encode::JP,
+Encode::JP::H2Z, Encode::JP::JIS7, Encode::KR, Encode::KR::2022_KR,
+Encode::MIME::Header, Encode::MIME::Name, Encode::PerlIO,
+Encode::Supported, Encode::Symbol, Encode::TW, Encode::Unicode,
+Encode::Unicode::UTF7, English, Env, Errno, Exporter, Exporter::Heavy,
+ExtUtils::CBuilder, ExtUtils::CBuilder::Platform::Windows,
+ExtUtils::Command, ExtUtils::Command::MM, ExtUtils::Constant,
+ExtUtils::Constant::Base, ExtUtils::Constant::Utils,
+ExtUtils::Constant::XS, ExtUtils::Embed, ExtUtils::Install,
+ExtUtils::Installed, ExtUtils::Liblist, ExtUtils::MM, ExtUtils::MM_AIX,
+ExtUtils::MM_Any, ExtUtils::MM_BeOS, ExtUtils::MM_Cygwin, ExtUtils::MM_DOS,
+ExtUtils::MM_Darwin, ExtUtils::MM_MacOS, ExtUtils::MM_NW5,
+ExtUtils::MM_OS2, ExtUtils::MM_QNX, ExtUtils::MM_UWIN, ExtUtils::MM_Unix,
+ExtUtils::MM_VMS, ExtUtils::MM_VOS, ExtUtils::MM_Win32, ExtUtils::MM_Win95,
+ExtUtils::MY, ExtUtils::MakeMaker, ExtUtils::MakeMaker::Config,
+ExtUtils::MakeMaker::FAQ, ExtUtils::MakeMaker::Tutorial,
+ExtUtils::Manifest, ExtUtils::Mkbootstrap, ExtUtils::Mksymlists,
+ExtUtils::Packlist, ExtUtils::ParseXS, ExtUtils::XSSymSet,
+ExtUtils::testlib, Fatal, Fcntl, File::Basename, File::CheckTree,
+File::Compare, File::Copy, File::DosGlob, File::Fetch, File::Find,
+File::Glob, File::GlobMapper, File::Path, File::Spec, File::Spec::Cygwin,
+File::Spec::Epoc, File::Spec::Functions, File::Spec::Mac, File::Spec::OS2,
+File::Spec::Unix, File::Spec::VMS, File::Spec::Win32, File::Temp,
+File::stat, FileCache, FileHandle, Filter::Simple, Filter::Util::Call,
+FindBin, GDBM_File, Getopt::Long, Getopt::Std, Hash::Util,
+Hash::Util::FieldHash, I18N::Collate, I18N::LangTags,
+I18N::LangTags::Detect, I18N::LangTags::List, I18N::Langinfo, IO,
+IO::Compress::Base, IO::Compress::Bzip2, IO::Compress::Deflate,
+IO::Compress::FAQ, IO::Compress::Gzip, IO::Compress::RawDeflate,
+IO::Compress::Zip, IO::Dir, IO::File, IO::Handle, IO::Pipe, IO::Poll,
+IO::Seekable, IO::Select, IO::Socket, IO::Socket::INET, IO::Socket::UNIX,
+IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress,
+IO::Uncompress::Base, IO::Uncompress::Bunzip2, IO::Uncompress::Gunzip,
+IO::Uncompress::Inflate, IO::Uncompress::RawInflate, IO::Uncompress::Unzip,
+IO::Zlib, IPC::Cmd, IPC::Msg, IPC::Open2, IPC::Open3, IPC::Semaphore,
+IPC::SharedMem, IPC::SysV, List::Util, List::Util::XS, Locale::Constants,
+Locale::Country, Locale::Currency, Locale::Language, Locale::Maketext,
+Locale::Maketext::Simple, Locale::Maketext::TPJ13, Locale::Script,
+Log::Message, Log::Message::Config, Log::Message::Handlers,
+Log::Message::Item, Log::Message::Simple, MIME::Base64, MIME::QuotedPrint,
+Math::BigFloat, Math::BigInt, Math::BigInt::Calc, Math::BigInt::CalcEmu,
+Math::BigInt::FastCalc, Math::BigRat, Math::Complex, Math::Trig, Memoize,
+Memoize::AnyDBM_File, Memoize::Expire, Memoize::ExpireFile,
+Memoize::ExpireTest, Memoize::NDBM_File, Memoize::SDBM_File,
+Memoize::Storable, Module::Build, Module::Build::API,
+Module::Build::Authoring, Module::Build::Base, Module::Build::Bundling,
+Module::Build::Compat, Module::Build::ConfigData, Module::Build::Cookbook,
+Module::Build::ModuleInfo, Module::Build::Notes, Module::Build::PPMMaker,
+Module::Build::Platform::Amiga, Module::Build::Platform::Default,
+Module::Build::Platform::EBCDIC, Module::Build::Platform::MPEiX,
+Module::Build::Platform::MacOS, Module::Build::Platform::RiscOS,
+Module::Build::Platform::Unix, Module::Build::Platform::VMS,
+Module::Build::Platform::VOS, Module::Build::Platform::Windows,
+Module::Build::Platform::aix, Module::Build::Platform::cygwin,
+Module::Build::Platform::darwin, Module::Build::Platform::os2,
+Module::CoreList, Module::Load, Module::Load::Conditional, Module::Loaded,
+Module::Pluggable, Module::Pluggable::Object, NDBM_File, NEXT, Net::Cmd,
+Net::Config, Net::Domain, Net::FTP, Net::NNTP, Net::Netrc, Net::POP3,
+Net::Ping, Net::SMTP, Net::Time, Net::hostent, Net::libnetFAQ, Net::netent,
+Net::protoent, Net::servent, O, ODBM_File, Object::Accessor, Opcode, POSIX,
+Package::Constants, Params::Check, Parse::CPAN::Meta, PerlIO,
+PerlIO::encoding, PerlIO::scalar, PerlIO::via, PerlIO::via::QuotedPrint,
+Pod::Checker, Pod::Escapes, Pod::Find, Pod::Functions, Pod::Html,
+Pod::InputObjects, Pod::LaTeX, Pod::Man, Pod::ParseLink, Pod::ParseUtils,
+Pod::Parser, Pod::Perldoc, Pod::Perldoc::BaseTo, Pod::Perldoc::GetOptsOO,
+Pod::Perldoc::ToChecker, Pod::Perldoc::ToMan, Pod::Perldoc::ToNroff,
+Pod::Perldoc::ToPod, Pod::Perldoc::ToRtf, Pod::Perldoc::ToText,
+Pod::Perldoc::ToTk, Pod::Perldoc::ToXml, Pod::PlainText, Pod::Plainer,
+Pod::Select, Pod::Simple, Pod::Simple::Checker, Pod::Simple::Debug,
+Pod::Simple::DumpAsText, Pod::Simple::DumpAsXML, Pod::Simple::HTML,
+Pod::Simple::HTMLBatch, Pod::Simple::LinkSection, Pod::Simple::Methody,
+Pod::Simple::PullParser, Pod::Simple::PullParserEndToken,
+Pod::Simple::PullParserStartToken, Pod::Simple::PullParserTextToken,
+Pod::Simple::PullParserToken, Pod::Simple::RTF, Pod::Simple::Search,
+Pod::Simple::SimpleTree, Pod::Simple::Subclassing, Pod::Simple::Text,
+Pod::Simple::TextContent, Pod::Simple::XHTML, Pod::Simple::XMLOutStream,
+Pod::Text, Pod::Text::Color, Pod::Text::Termcap, Pod::Usage, SDBM_File,
+Safe, Scalar::Util, Search::Dict, SelectSaver, SelfLoader, Shell, Socket,
+Storable, Switch, Symbol, Sys::Hostname, Sys::Syslog, Sys::Syslog::Win32,
+TAP::Base, TAP::Formatter::Color, TAP::Formatter::Console,
+TAP::Formatter::Console, TAP::Formatter::Console::ParallelSession,
+TAP::Formatter::Console::Session, TAP::Formatter::File,
+TAP::Formatter::File::Session, TAP::Formatter::Session, TAP::Harness,
+TAP::Object, TAP::Parser, TAP::Parser::Aggregator, TAP::Parser::Grammar,
+TAP::Parser::Iterator, TAP::Parser::Iterator::Array,
+TAP::Parser::Iterator::Process, TAP::Parser::Iterator::Stream,
+TAP::Parser::IteratorFactory, TAP::Parser::Multiplexer,
+TAP::Parser::Result, TAP::Parser::Result::Bailout,
+TAP::Parser::Result::Comment, TAP::Parser::Result::Plan,
+TAP::Parser::Result::Pragma, TAP::Parser::Result::Test,
+TAP::Parser::Result::Unknown, TAP::Parser::Result::Version,
+TAP::Parser::Result::YAML, TAP::Parser::ResultFactory,
+TAP::Parser::Scheduler, TAP::Parser::Scheduler::Job,
+TAP::Parser::Scheduler::Spinner, TAP::Parser::Source,
+TAP::Parser::Source::Perl, TAP::Parser::Utils,
+TAP::Parser::YAMLish::Reader, TAP::Parser::YAMLish::Writer,
+Term::ANSIColor, Term::Cap, Term::Complete, Term::ReadLine, Term::UI, Test,
+Test::Builder, Test::Builder::Module, Test::Builder::Tester,
+Test::Builder::Tester::Color, Test::Harness, Test::More, Test::Simple,
+Test::Tutorial, Text::Abbrev, Text::Balanced, Text::ParseWords,
+Text::Soundex, Text::Tabs, Text::Wrap, Thread, Thread::Queue,
+Thread::Semaphore, Tie::Array, Tie::File, Tie::Handle, Tie::Hash,
+Tie::Hash::NamedCapture, Tie::Memoize, Tie::RefHash, Tie::Scalar,
+Tie::StdHandle, Tie::SubstrHash, Time::HiRes, Time::Local, Time::Piece,
+Time::Seconds, Time::gmtime, Time::localtime, Time::tm, UNIVERSAL,
+Unicode::Collate, Unicode::Normalize, Unicode::UCD, User::grent,
+User::pwent, VMS::DCLsym, VMS::Stdio, Win32, Win32API::File, Win32CORE,
+XS::APItest, XS::APItest::KeywordRPN, XS::Typemap, XSLoader,
+version::Internals
+
+=item Extension Modules
+
+=back
+
+=item CPAN
+
+=over 4
+
+=item Africa
+
+South Africa
+
+=item Asia
+
+Hong Kong, India, Indonesia, Japan, Kazakhstan, Republic of Korea, Russia,
+Singapore, Taiwan, Thailand, Turkey, Viet Nam
+
+=item Central America
+
+Costa Rica
+
+=item Europe
+
+Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech
+Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland,
+Ireland, Italy, Latvia, Lithuania, Malta, Netherlands, Norway, Poland,
+Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
+Ukraine, United Kingdom
+
+=item North America
+
+Bahamas, Canada, Mexico, United States, Alabama, California, Florida,
+Idaho, Illinois, Indiana, Massachusetts, Michigan, Minnesota, New Jersey,
+New York, North Carolina, Oregon, Pennsylvania, South Carolina, Tennessee,
+Texas, Utah, Virginia, Washington, Wisconsin
+
+=item Oceania
+
+Australia, New Zealand
+
+=item South America
+
+Argentina, Brazil, Chile, Colombia
+
+=item RSYNC Mirrors
+
+=back
+
+=item Modules: Creation, Use, and Abuse
+
+=over 4
+
+=item Guidelines for Module Creation
+
+=item Guidelines for Converting Perl 4 Library Scripts into Modules
+
+=item Guidelines for Reusing Application Code
+
+=back
+
+=item NOTE
+
+=back
+
+=head2 perlmodstyle - Perl module style guide
+
+=over 4
+
+=item INTRODUCTION
+
+=item QUICK CHECKLIST
+
+=over 4
+
+=item Before you start
+
+=item The API
+
+=item Stability
+
+=item Documentation
+
+=item Release considerations
+
+=back
+
+=item BEFORE YOU START WRITING A MODULE
+
+=over 4
+
+=item Has it been done before?
+
+=item Do one thing and do it well
+
+=item What's in a name?
+
+=back
+
+=item DESIGNING AND WRITING YOUR MODULE
+
+=over 4
+
+=item To OO or not to OO?
+
+=item Designing your API
+
+Write simple routines to do simple things, Separate functionality from
+output, Provide sensible shortcuts and defaults, Naming conventions,
+Parameter passing
+
+=item Strictness and warnings
+
+=item Backwards compatibility
+
+=item Error handling and messages
+
+=back
+
+=item DOCUMENTING YOUR MODULE
+
+=over 4
+
+=item POD
+
+=item README, INSTALL, release notes, changelogs
+
+perl Makefile.PL, make, make test, make install, perl Build.PL, perl Build,
+perl Build test, perl Build install
+
+=back
+
+=item RELEASE CONSIDERATIONS
+
+=over 4
+
+=item Version numbering
+
+=item Pre-requisites
+
+=item Testing
+
+=item Packaging
+
+=item Licensing
+
+=back
+
+=item COMMON PITFALLS
+
+=over 4
+
+=item Reinventing the wheel
+
+=item Trying to do too much
+
+=item Inappropriate documentation
+
+=back
+
+=item SEE ALSO
+
+L<perlstyle>, L<perlnewmod>, L<perlpod>, L<podchecker>, Packaging Tools,
+Testing tools, http://pause.perl.org/, Any good book on software
+engineering
+
+=item AUTHOR
+
+=back
+
+=head2 perlmodinstall - Installing CPAN Modules
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item PREAMBLE
+
+B<DECOMPRESS> the file, B<UNPACK> the file into a directory, B<BUILD> the
+module (sometimes unnecessary), B<INSTALL> the module
+
+=back
+
+=item PORTABILITY
+
+=item HEY
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 perlnewmod - preparing a new module for distribution
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Warning
+
+=item What should I make into a module?
+
+=item Step-by-step: Preparing the ground
+
+Look around, Check it's new, Discuss the need, Choose a name, Check again
+
+=item Step-by-step: Making the module
+
+Start with F<module-starter> or F<h2xs>, Use L<strict|strict> and
+L<warnings|warnings>, Use L<Carp|Carp>, Use L<Exporter|Exporter> - wisely!,
+Use L<plain old documentation|perlpod>, Write tests, Write the README
+
+=item Step-by-step: Distributing your module
+
+Get a CPAN user ID, C<perl Makefile.PL; make test; make dist>, Upload the
+tarball, Announce to the modules list, Announce to clpa, Fix bugs!
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlpragma - how to write a user pragma
+
+=over 4
+
+=item DESCRIPTION
+
+=item A basic example
+
+=item Implementation details
+
+=back
+
+=head2 perlutil - utilities packaged with the Perl distribution
+
+=over 4
+
+=item DESCRIPTION
+
+=item LIST OF UTILITIES
+
+=over 4
+
+=item Documentation
+
+L<perldoc|perldoc>, L<pod2man|pod2man> and L<pod2text|pod2text>,
+L<pod2html|pod2html> and L<pod2latex|pod2latex>, L<pod2usage|pod2usage>,
+L<podselect|podselect>, L<podchecker|podchecker>, L<splain|splain>,
+L<roffitall|roffitall>
+
+=item Convertors
+
+L<a2p|a2p>, L<s2p|s2p> and L<psed>, L<find2perl|find2perl>
+
+=item Administration
+
+L<config_data|config_data>, L<libnetcfg|libnetcfg>, L<perlivp>
+
+=item Development
+
+L<perlbug|perlbug>, L<perlthanks|perlthanks>, L<h2ph|h2ph>, L<c2ph|c2ph>
+and L<pstruct|pstruct>, L<h2xs|h2xs>, L<enc2xs>, L<xsubpp>,
+L<dprofpp|dprofpp>, L<prove>, L<corelist>
+
+=item General tools
+
+L<piconv>, L<ptar>, L<ptardiff>, L<shasum>
+
+=item Installation
+
+L<cpan>, L<cpanp>, L<cpan2dist>, L<instmodsh>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlcompile - Introduction to the Perl Compiler-Translator
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Layout
+
+B::Lint, B::Deparse, B::Xref
+
+=back
+
+=item Using The Back Ends
+
+=over 4
+
+=item The Cross Referencing Back End
+
+i, &, s, r
+
+=item The Decompiling Back End
+
+=item The Lint Back End
+
+=back
+
+=item Module List for the Compiler Suite
+
+B, O, B::Concise, B::Debug, B::Deparse, B::Lint, B::Showlex, B::Terse,
+B::Xref
+
+=item KNOWN PROBLEMS
+
+=item AUTHOR
+
+=back
+
+=head2 perlfilter - Source Filters
+
+=over 4
+
+=item DESCRIPTION
+
+=item CONCEPTS
+
+=item USING FILTERS
+
+=item WRITING A SOURCE FILTER
+
+=item WRITING A SOURCE FILTER IN C
+
+B<Decryption Filters>
+
+=item CREATING A SOURCE FILTER AS A SEPARATE EXECUTABLE
+
+=item WRITING A SOURCE FILTER IN PERL
+
+=item USING CONTEXT: THE DEBUG FILTER
+
+=item CONCLUSION
+
+=item THINGS TO LOOK OUT FOR
+
+Some Filters Clobber the C<DATA> Handle
+
+=item REQUIREMENTS
+
+=item AUTHOR
+
+=item Copyrights
+
+=back
+
+=head2 perlglossary - Perl Glossary
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item A
+
+accessor methods, actual arguments, address operator, algorithm, alias,
+alternatives, anonymous, architecture, argument, ARGV, arithmetical
+operator, array, array context, ASCII, assertion, assignment, assignment
+operator, associative array, associativity, asynchronous, atom, atomic
+operation, attribute, autogeneration, autoincrement, autoload, autosplit,
+autovivification, AV, awk
+
+=item B
+
+backreference, backtracking, backward compatibility, bareword, base class,
+big-endian, binary, binary operator, bind, bit, bit shift, bit string,
+bless, block, BLOCK, block buffering, Boolean, Boolean context, breakpoint,
+broadcast, BSD, bucket, buffer, built-in, bundle, byte, bytecode
+
+=item C
+
+C, C preprocessor, call by reference, call by value, callback, canonical,
+capturing, character, character class, character property, circumfix
+operator, class, class method, client, cloister, closure, cluster, CODE,
+code generator, code subpattern, collating sequence, command, command
+buffering, command name, command-line arguments, comment, compilation unit,
+compile phase, compile time, compiler, composer, concatenation,
+conditional, connection, construct, constructor, context, continuation,
+core dump, CPAN, cracker, current package, current working directory,
+currently selected output channel, CV
+
+=item D
+
+dangling statement, data structure, data type, datagram, DBM, declaration,
+decrement, default, defined, delimiter, deprecated modules and features,
+dereference, derived class, descriptor, destroy, destructor, device,
+directive, directory, directory handle, dispatch, distribution, (to be)
+dropped modules, dweomer, dwimmer, dynamic scoping
+
+=item E
+
+eclectic, element, embedding, empty subclass test, en passant,
+encapsulation, endian, environment, environment variable, EOF, errno,
+error, escape sequence, exception, exception handling, exec, executable
+file, execute, execute bit, exit status, export, expression, extension
+
+=item F
+
+false, FAQ, fatal error, field, FIFO, file, file descriptor, file test
+operator, fileglob, filehandle, filename, filesystem, filter, flag,
+floating point, flush, FMTEYEWTK, fork, formal arguments, format, freely
+available, freely redistributable, freeware, function, funny character,
+garbage collection
+
+=item G
+
+GID, glob, global, global destruction, glue language, granularity, greedy,
+grep, group, GV
+
+=item H
+
+hacker, handler, hard reference, hash, hash table, header file, here
+document, hexadecimal, home directory, host, hubris, HV
+
+=item I
+
+identifier, impatience, implementation, import, increment, indexing,
+indirect filehandle, indirect object, indirect object slot, indirection,
+infix, inheritance, instance, instance variable, integer, interface,
+interpolation, interpreter, invocant, invocation, I/O, IO, IP, IPC, is-a,
+iteration, iterator, IV
+
+=item J
+
+JAPH
+
+=item K
+
+key, keyword
+
+=item L
+
+label, laziness, left shift, leftmost longest, lexeme, lexer, lexical
+analysis, lexical scoping, lexical variable, library, LIFO, line, line
+buffering, line number, link, LIST, list, list context, list operator, list
+value, literal, little-endian, local, logical operator, lookahead,
+lookbehind, loop, loop control statement, loop label, lvaluable, lvalue,
+lvalue modifier
+
+=item M
+
+magic, magical increment, magical variables, Makefile, man, manpage,
+matching, member data, memory, metacharacter, metasymbol, method,
+minimalism, mode, modifier, module, modulus, monger, mortal,
+multidimensional array, multiple inheritance
+
+=item N
+
+named pipe, namespace, network address, newline, NFS, null character, null
+list, null string, numeric context, NV, nybble
+
+=item O
+
+object, octal, offset, one-liner, open source software, operand, operating
+system, operator, operator overloading, options, overloading, overriding,
+owner
+
+=item P
+
+package, pad, parameter, parent class, parse tree, parsing, patch, PATH,
+pathname, pattern, pattern matching, permission bits, Pern, pipe, pipeline,
+platform, pod, pointer, polymorphism, port, portable, porter, POSIX,
+postfix, pp, pragma, precedence, prefix, preprocessing, procedure, process,
+program generator, progressive matching, property, protocol, prototype,
+pseudofunction, pseudohash, pseudoliteral, public domain, pumpkin,
+pumpking, PV
+
+=item Q
+
+qualified, quantifier
+
+=item R
+
+readable, reaping, record, recursion, reference, referent, regex, regular
+expression, regular expression modifier, regular file, relational operator,
+reserved words, return value, RFC, right shift, root, RTFM, run phase, run
+time, run-time pattern, RV, rvalue
+
+=item S
+
+scalar, scalar context, scalar literal, scalar value, scalar variable,
+scope, scratchpad, script, script kiddie, sed, semaphore, separator,
+serialization, server, service, setgid, setuid, shared memory, shebang,
+shell, side effects, signal, signal handler, single inheritance, slice,
+slurp, socket, soft reference, source filter, stack, standard, standard
+error, standard I/O, standard input, standard output, stat structure,
+statement, statement modifier, static, static method, static scoping,
+static variable, status, STDERR, STDIN, STDIO, STDOUT, stream, string,
+string context, stringification, struct, structure, subclass, subpattern,
+subroutine, subscript, substitution, substring, superclass, superuser, SV,
+switch, switch cluster, switch statement, symbol, symbol table, symbolic
+debugger, symbolic link, symbolic reference, synchronous, syntactic sugar,
+syntax, syntax tree, syscall
+
+=item T
+
+tainted, TCP, term, terminator, ternary, text, thread, tie, TMTOWTDI,
+token, tokener, tokenizing, toolbox approach, transliterate, trigger,
+trinary, troff, true, truncating, type, type casting, typed lexical,
+typedef, typeglob, typemap
+
+=item U
+
+UDP, UID, umask, unary operator, Unicode, Unix
+
+=item V
+
+value, variable, variable interpolation, variadic, vector, virtual, void
+context, v-string
+
+=item W
+
+warning, watch expression, whitespace, word, working directory, wrapper,
+WYSIWYG
+
+=item X
+
+XS, XSUB
+
+=item Y
+
+yacc
+
+=item Z
+
+zero width, zombie
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 perlembed - how to embed perl in your C program
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item PREAMBLE
+
+B<Use C from Perl?>, B<Use a Unix program from Perl?>, B<Use Perl from
+Perl?>, B<Use C from C?>, B<Use Perl from C?>
+
+=item ROADMAP
+
+=item Compiling your C program
+
+=item Adding a Perl interpreter to your C program
+
+=item Calling a Perl subroutine from your C program
+
+=item Evaluating a Perl statement from your C program
+
+=item Performing Perl pattern matches and substitutions from your C program
+
+=item Fiddling with the Perl stack from your C program
+
+=item Maintaining a persistent interpreter
+
+=item Execution of END blocks
+
+=item $0 assignments
+
+=item Maintaining multiple interpreter instances
+
+=item Using Perl modules, which themselves use C libraries, from your C
+program
+
+=back
+
+=item Embedding Perl under Win32
+
+=item Hiding Perl_
+
+=item MORAL
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 perldebguts - Guts of Perl debugging
+
+=over 4
+
+=item DESCRIPTION
+
+=item Debugger Internals
+
+=over 4
+
+=item Writing Your Own Debugger
+
+=back
+
+=item Frame Listing Output Examples
+
+=item Debugging regular expressions
+
+=over 4
+
+=item Compile-time output
+
+C<anchored> I<STRING> C<at> I<POS>, C<floating> I<STRING> C<at>
+I<POS1..POS2>, C<matching floating/anchored>, C<minlen>, C<stclass>
+I<TYPE>, C<noscan>, C<isall>, C<GPOS>, C<plus>, C<implicit>, C<with eval>,
+C<anchored(TYPE)>
+
+=item Types of nodes
+
+=item Run-time output
+
+=back
+
+=item Debugging Perl memory usage
+
+=over 4
+
+=item Using C<$ENV{PERL_DEBUG_MSTATS}>
+
+C<buckets SMALLEST(APPROX)..GREATEST(APPROX)>, Free/Used, C<Total sbrk():
+SBRKed/SBRKs:CONTINUOUS>, C<pad: 0>, C<heads: 2192>, C<chain: 0>, C<tail:
+6144>
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlxstut, perlXStut - Tutorial for writing XSUBs
+
+=over 4
+
+=item DESCRIPTION
+
+=item SPECIAL NOTES
+
+=over 4
+
+=item make
+
+=item Version caveat
+
+=item Dynamic Loading versus Static Loading
+
+=back
+
+=item TUTORIAL
+
+=over 4
+
+=item EXAMPLE 1
+
+=item EXAMPLE 2
+
+=item What has gone on?
+
+=item Writing good test scripts
+
+=item EXAMPLE 3
+
+=item What's new here?
+
+=item Input and Output Parameters
+
+=item The XSUBPP Program
+
+=item The TYPEMAP file
+
+=item Warning about Output Arguments
+
+=item EXAMPLE 4
+
+=item What has happened here?
+
+=item Anatomy of .xs file
+
+=item Getting the fat out of XSUBs
+
+=item More about XSUB arguments
+
+=item The Argument Stack
+
+=item Extending your Extension
+
+=item Documenting your Extension
+
+=item Installing your Extension
+
+=item EXAMPLE 5
+
+=item New Things in this Example
+
+=item EXAMPLE 6
+
+=item New Things in this Example
+
+=item EXAMPLE 7 (Coming Soon)
+
+=item EXAMPLE 8 (Coming Soon)
+
+=item EXAMPLE 9 Passing open files to XSes
+
+=item Troubleshooting these Examples
+
+=back
+
+=item See also
+
+=item Author
+
+=over 4
+
+=item Last Changed
+
+=back
+
+=back
+
+=head2 perlxs - XS language reference manual
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Introduction
+
+=item On The Road
+
+=item The Anatomy of an XSUB
+
+=item The Argument Stack
+
+=item The RETVAL Variable
+
+=item Returning SVs, AVs and HVs through RETVAL
+
+=item The MODULE Keyword
+
+=item The PACKAGE Keyword
+
+=item The PREFIX Keyword
+
+=item The OUTPUT: Keyword
+
+=item The NO_OUTPUT Keyword
+
+=item The CODE: Keyword
+
+=item The INIT: Keyword
+
+=item The NO_INIT Keyword
+
+=item Initializing Function Parameters
+
+=item Default Parameter Values
+
+=item The PREINIT: Keyword
+
+=item The SCOPE: Keyword
+
+=item The INPUT: Keyword
+
+=item The IN/OUTLIST/IN_OUTLIST/OUT/IN_OUT Keywords
+
+=item The C<length(NAME)> Keyword
+
+=item Variable-length Parameter Lists
+
+=item The C_ARGS: Keyword
+
+=item The PPCODE: Keyword
+
+=item Returning Undef And Empty Lists
+
+=item The REQUIRE: Keyword
+
+=item The CLEANUP: Keyword
+
+=item The POSTCALL: Keyword
+
+=item The BOOT: Keyword
+
+=item The VERSIONCHECK: Keyword
+
+=item The PROTOTYPES: Keyword
+
+=item The PROTOTYPE: Keyword
+
+=item The ALIAS: Keyword
+
+=item The OVERLOAD: Keyword
+
+=item The FALLBACK: Keyword
+
+=item The INTERFACE: Keyword
+
+=item The INTERFACE_MACRO: Keyword
+
+=item The INCLUDE: Keyword
+
+=item The CASE: Keyword
+
+=item The & Unary Operator
+
+=item Inserting POD, Comments and C Preprocessor Directives
+
+=item Using XS With C++
+
+=item Interface Strategy
+
+=item Perl Objects And C Structures
+
+=item The Typemap
+
+=item Safely Storing Static Data in XS
+
+MY_CXT_KEY, typedef my_cxt_t, START_MY_CXT, MY_CXT_INIT, dMY_CXT, MY_CXT,
+aMY_CXT/pMY_CXT, MY_CXT_CLONE, MY_CXT_INIT_INTERP(my_perl),
+dMY_CXT_INTERP(my_perl)
+
+=item Thread-aware system interfaces
+
+=back
+
+=item EXAMPLES
+
+=item XS VERSION
+
+=item AUTHOR
+
+=back
+
+=head2 perlclib - Internal replacements for standard C library functions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Conventions
+
+C<t>, C<p>, C<n>, C<s>
+
+=item File Operations
+
+=item File Input and Output
+
+=item File Positioning
+
+=item Memory Management and String Handling
+
+=item Character Class Tests
+
+=item F<stdlib.h> functions
+
+=item Miscellaneous functions
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 perlguts - Introduction to the Perl API
+
+=over 4
+
+=item DESCRIPTION
+
+=item Variables
+
+=over 4
+
+=item Datatypes
+
+=item What is an "IV"?
+
+=item Working with SVs
+
+=item Offsets
+
+=item What's Really Stored in an SV?
+
+=item Working with AVs
+
+=item Working with HVs
+
+=item Hash API Extensions
+
+=item AVs, HVs and undefined values
+
+=item References
+
+=item Blessed References and Class Objects
+
+=item Creating New Variables
+
+GV_ADDMULTI, GV_ADDWARN
+
+=item Reference Counts and Mortality
+
+=item Stashes and Globs
+
+=item Double-Typed SVs
+
+=item Magic Variables
+
+=item Assigning Magic
+
+=item Magic Virtual Tables
+
+=item Finding Magic
+
+=item Understanding the Magic of Tied Hashes and Arrays
+
+=item Localizing changes
+
+C<SAVEINT(int i)>, C<SAVEIV(IV i)>, C<SAVEI32(I32 i)>, C<SAVELONG(long i)>,
+C<SAVESPTR(s)>, C<SAVEPPTR(p)>, C<SAVEFREESV(SV *sv)>, C<SAVEMORTALIZESV(SV
+*sv)>, C<SAVEFREEOP(OP *op)>, C<SAVEFREEPV(p)>, C<SAVECLEARSV(SV *sv)>,
+C<SAVEDELETE(HV *hv, char *key, I32 length)>,
+C<SAVEDESTRUCTOR(DESTRUCTORFUNC_NOCONTEXT_t f, void *p)>,
+C<SAVEDESTRUCTOR_X(DESTRUCTORFUNC_t f, void *p)>, C<SAVESTACK_POS()>, C<SV*
+save_scalar(GV *gv)>, C<AV* save_ary(GV *gv)>, C<HV* save_hash(GV *gv)>,
+C<void save_item(SV *item)>, C<void save_list(SV **sarg, I32 maxsarg)>,
+C<SV* save_svref(SV **sptr)>, C<void save_aptr(AV **aptr)>, C<void
+save_hptr(HV **hptr)>
+
+=back
+
+=item Subroutines
+
+=over 4
+
+=item XSUBs and the Argument Stack
+
+=item Calling Perl Routines from within C Programs
+
+=item Memory Allocation
+
+=item PerlIO
+
+=item Putting a C value on Perl stack
+
+=item Scratchpads
+
+=item Scratchpads and recursion
+
+=back
+
+=item Compiled code
+
+=over 4
+
+=item Code tree
+
+=item Examining the tree
+
+=item Compile pass 1: check routines
+
+=item Compile pass 1a: constant folding
+
+=item Compile pass 2: context propagation
+
+=item Compile pass 3: peephole optimization
+
+=item Pluggable runops
+
+=back
+
+=item Examining internal data structures with the C<dump> functions
+
+=item How multiple interpreters and concurrency are supported
+
+=over 4
+
+=item Background and PERL_IMPLICIT_CONTEXT
+
+=item So what happened to dTHR?
+
+=item How do I use all this in extensions?
+
+=item Should I do anything special if I call perl from multiple threads?
+
+=item Future Plans and PERL_IMPLICIT_SYS
+
+=back
+
+=item Internal Functions
+
+A, p, d, s, n, r, f, M, o, x, m, X, E, b, others
+
+=over 4
+
+=item Formatted Printing of IVs, UVs, and NVs
+
+=item Pointer-To-Integer and Integer-To-Pointer
+
+=item Exception Handling
+
+=item Source Documentation
+
+=item Backwards compatibility
+
+=back
+
+=item Unicode Support
+
+=over 4
+
+=item What B<is> Unicode, anyway?
+
+=item How can I recognise a UTF-8 string?
+
+=item How does UTF-8 represent Unicode characters?
+
+=item How does Perl store UTF-8 strings?
+
+=item How do I convert a string to UTF-8?
+
+=item Is there anything else I need to know?
+
+=back
+
+=item Custom Operators
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 perlcall - Perl calling conventions from C
+
+=over 4
+
+=item DESCRIPTION
+
+An Error Handler, An Event Driven Program
+
+=item THE CALL_ FUNCTIONS
+
+call_sv, call_pv, call_method, call_argv
+
+=item FLAG VALUES
+
+=over 4
+
+=item G_VOID
+
+=item G_SCALAR
+
+=item G_ARRAY
+
+=item G_DISCARD
+
+=item G_NOARGS
+
+=item G_EVAL
+
+=item G_KEEPERR
+
+=item Determining the Context
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item No Parameters, Nothing returned
+
+=item Passing Parameters
+
+=item Returning a Scalar
+
+=item Returning a list of values
+
+=item Returning a list in a scalar context
+
+=item Returning Data from Perl via the parameter list
+
+=item Using G_EVAL
+
+=item Using G_KEEPERR
+
+=item Using call_sv
+
+=item Using call_argv
+
+=item Using call_method
+
+=item Using GIMME_V
+
+=item Using Perl to dispose of temporaries
+
+=item Strategies for storing Callback Context Information
+
+1. Ignore the problem - Allow only 1 callback, 2. Create a sequence of
+callbacks - hard wired limit, 3. Use a parameter to map to the Perl
+callback
+
+=item Alternate Stack Manipulation
+
+=item Creating and calling an anonymous subroutine in C
+
+=back
+
+=item LIGHTWEIGHT CALLBACKS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item DATE
+
+=back
+
+=head2 perlmroapi - Perl method resolution plugin interface
+
+=over 4
+
+=item DESCRIPTION
+
+resolve, name, length, kflags, hash
+
+=item Callbacks
+
+=item Caching
+
+=item Examples
+
+=item AUTHORS
+
+=back
+
+=head2 perlreapi - perl regular expression plugin interface
+
+=over 4
+
+=item DESCRIPTION
+
+=item Callbacks
+
+=over 4
+
+=item comp
+
+C</m> - RXf_PMf_MULTILINE, C</s> - RXf_PMf_SINGLELINE, C</i> -
+RXf_PMf_FOLD, C</x> - RXf_PMf_EXTENDED, C</p> - RXf_PMf_KEEPCOPY,
+RXf_PMf_LOCALE, RXf_UTF8, RXf_SPLIT, RXf_SKIPWHITE, RXf_START_ONLY,
+RXf_WHITE, RXf_NULL
+
+=item exec
+
+=item intuit
+
+=item checkstr
+
+=item free
+
+=item Numbered capture callbacks
+
+=item Named capture callbacks
+
+=item qr_package
+
+=item dupe
+
+=back
+
+=item The REGEXP structure
+
+=over 4
+
+=item C<engine>
+
+=item C<mother_re>
+
+=item C<extflags>
+
+=item C<minlen> C<minlenret>
+
+=item C<gofs>
+
+=item C<substrs>
+
+=item C<nparens>, C<lasparen>, and C<lastcloseparen>
+
+=item C<intflags>
+
+=item C<pprivate>
+
+=item C<swap>
+
+=item C<offs>
+
+=item C<precomp> C<prelen>
+
+=item C<paren_names>
+
+=item C<substrs>
+
+=item C<subbeg> C<sublen> C<saved_copy>
+
+=item C<wrapped> C<wraplen>
+
+=item C<seen_evals>
+
+=item C<refcnt>
+
+=back
+
+=item HISTORY
+
+=item AUTHORS
+
+=item LICENSE
+
+=back
+
+=head2 perlreguts - Description of the Perl regular expression engine.
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERVIEW
+
+=over 4
+
+=item A quick note on terms
+
+=item What is a regular expression engine?
+
+=item Structure of a Regexp Program
+
+C<regnode_1>, C<regnode_2>, C<regnode_string>, C<regnode_charclass>,
+C<regnode_charclass_class>
+
+=back
+
+=item Process Overview
+
+A. Compilation, 1. Parsing for size, 2. Parsing for construction, 3.
+Peep-hole optimisation and analysis, B. Execution, 4. Start position and
+no-match optimisations, 5. Program execution
+
+=over 4
+
+=item Compilation
+
+anchored fixed strings, floating fixed strings, minimum and maximum length
+requirements, start class, Beginning/End of line positions
+
+=item Execution
+
+=back
+
+=item MISCELLANEOUS
+
+=over 4
+
+=item Unicode and Localisation Support
+
+=item Base Structures
+
+C<swap>, C<offsets>, C<regstclass>, C<data>, C<program>
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item LICENCE
+
+=item REFERENCES
+
+=back
+
+=head2 perlapi - autogenerated documentation for the perl public API
+
+=over 4
+
+=item DESCRIPTION
+X<Perl API> X<API> X<api>
+
+=item "Gimme" Values
+
+GIMME X<GIMME>, GIMME_V X<GIMME_V>, G_ARRAY X<G_ARRAY>, G_DISCARD
+X<G_DISCARD>, G_EVAL X<G_EVAL>, G_NOARGS X<G_NOARGS>, G_SCALAR X<G_SCALAR>,
+G_VOID X<G_VOID>
+
+=item Array Manipulation Functions
+
+AvFILL X<AvFILL>, av_clear X<av_clear>, av_create_and_push
+X<av_create_and_push>, av_create_and_unshift_one
+X<av_create_and_unshift_one>, av_delete X<av_delete>, av_exists
+X<av_exists>, av_extend X<av_extend>, av_fetch X<av_fetch>, av_fill
+X<av_fill>, av_len X<av_len>, av_make X<av_make>, av_pop X<av_pop>, av_push
+X<av_push>, av_shift X<av_shift>, av_store X<av_store>, av_undef
+X<av_undef>, av_unshift X<av_unshift>, get_av X<get_av>, newAV X<newAV>,
+sortsv X<sortsv>, sortsv_flags X<sortsv_flags>
+
+=item Callback Functions
+
+call_argv X<call_argv>, call_method X<call_method>, call_pv X<call_pv>,
+call_sv X<call_sv>, ENTER X<ENTER>, eval_pv X<eval_pv>, eval_sv X<eval_sv>,
+FREETMPS X<FREETMPS>, LEAVE X<LEAVE>, SAVETMPS X<SAVETMPS>
+
+=item Character classes
+
+isALNUM X<isALNUM>, isALPHA X<isALPHA>, isDIGIT X<isDIGIT>, isLOWER
+X<isLOWER>, isSPACE X<isSPACE>, isUPPER X<isUPPER>, toLOWER X<toLOWER>,
+toUPPER X<toUPPER>
+
+=item Cloning an interpreter
+
+perl_clone X<perl_clone>
+
+=item CV Manipulation Functions
+
+CvSTASH X<CvSTASH>, get_cv X<get_cv>, get_cvn_flags X<get_cvn_flags>
+
+=item Embedding Functions
+
+cv_undef X<cv_undef>, load_module X<load_module>, nothreadhook
+X<nothreadhook>, perl_alloc X<perl_alloc>, perl_construct
+X<perl_construct>, perl_destruct X<perl_destruct>, perl_free X<perl_free>,
+perl_parse X<perl_parse>, perl_run X<perl_run>, require_pv X<require_pv>
+
+=item Functions in file dump.c
+
+pv_display X<pv_display>, pv_escape X<pv_escape>, pv_pretty X<pv_pretty>
+
+=item Functions in file mathoms.c
+
+gv_fetchmethod X<gv_fetchmethod>, pack_cat X<pack_cat>, sv_2pvbyte_nolen
+X<sv_2pvbyte_nolen>, sv_2pvutf8_nolen X<sv_2pvutf8_nolen>, sv_2pv_nolen
+X<sv_2pv_nolen>, sv_catpvn_mg X<sv_catpvn_mg>, sv_catsv_mg X<sv_catsv_mg>,
+sv_force_normal X<sv_force_normal>, sv_iv X<sv_iv>, sv_nolocking
+X<sv_nolocking>, sv_nounlocking X<sv_nounlocking>, sv_nv X<sv_nv>, sv_pv
+X<sv_pv>, sv_pvbyte X<sv_pvbyte>, sv_pvbyten X<sv_pvbyten>, sv_pvn
+X<sv_pvn>, sv_pvutf8 X<sv_pvutf8>, sv_pvutf8n X<sv_pvutf8n>, sv_taint
+X<sv_taint>, sv_unref X<sv_unref>, sv_usepvn X<sv_usepvn>, sv_usepvn_mg
+X<sv_usepvn_mg>, sv_uv X<sv_uv>, unpack_str X<unpack_str>
+
+=item Functions in file perl.h
+
+PERL_SYS_INIT X<PERL_SYS_INIT>, PERL_SYS_INIT3 X<PERL_SYS_INIT3>,
+PERL_SYS_TERM X<PERL_SYS_TERM>
+
+=item Functions in file pp_ctl.c
+
+find_runcv X<find_runcv>
+
+=item Functions in file pp_pack.c
+
+packlist X<packlist>, unpackstring X<unpackstring>
+
+=item Functions in file pp_sys.c
+
+setdefout X<setdefout>
+
+=item Global Variables
+
+PL_keyword_plugin X<PL_keyword_plugin>
+
+=item GV Functions
+
+GvSV X<GvSV>, gv_const_sv X<gv_const_sv>, gv_fetchmeth X<gv_fetchmeth>,
+gv_fetchmethod_autoload X<gv_fetchmethod_autoload>, gv_fetchmeth_autoload
+X<gv_fetchmeth_autoload>, gv_stashpv X<gv_stashpv>, gv_stashpvn
+X<gv_stashpvn>, gv_stashpvs X<gv_stashpvs>, gv_stashsv X<gv_stashsv>
+
+=item Handy Values
+
+Nullav X<Nullav>, Nullch X<Nullch>, Nullcv X<Nullcv>, Nullhv X<Nullhv>,
+Nullsv X<Nullsv>
+
+=item Hash Manipulation Functions
+
+get_hv X<get_hv>, HEf_SVKEY X<HEf_SVKEY>, HeHASH X<HeHASH>, HeKEY X<HeKEY>,
+HeKLEN X<HeKLEN>, HePV X<HePV>, HeSVKEY X<HeSVKEY>, HeSVKEY_force
+X<HeSVKEY_force>, HeSVKEY_set X<HeSVKEY_set>, HeUTF8 X<HeUTF8>, HeVAL
+X<HeVAL>, HvNAME X<HvNAME>, hv_assert X<hv_assert>, hv_clear X<hv_clear>,
+hv_clear_placeholders X<hv_clear_placeholders>, hv_delete X<hv_delete>,
+hv_delete_ent X<hv_delete_ent>, hv_exists X<hv_exists>, hv_exists_ent
+X<hv_exists_ent>, hv_fetch X<hv_fetch>, hv_fetchs X<hv_fetchs>,
+hv_fetch_ent X<hv_fetch_ent>, hv_iterinit X<hv_iterinit>, hv_iterkey
+X<hv_iterkey>, hv_iterkeysv X<hv_iterkeysv>, hv_iternext X<hv_iternext>,
+hv_iternextsv X<hv_iternextsv>, hv_iternext_flags X<hv_iternext_flags>,
+hv_iterval X<hv_iterval>, hv_magic X<hv_magic>, hv_scalar X<hv_scalar>,
+hv_store X<hv_store>, hv_stores X<hv_stores>, hv_store_ent X<hv_store_ent>,
+hv_undef X<hv_undef>, newHV X<newHV>
+
+=item Lexer interface
+
+lex_bufutf8 X<lex_bufutf8>, lex_discard_to X<lex_discard_to>,
+lex_grow_linestr X<lex_grow_linestr>, lex_next_chunk X<lex_next_chunk>,
+lex_peek_unichar X<lex_peek_unichar>, lex_read_space X<lex_read_space>,
+lex_read_to X<lex_read_to>, lex_read_unichar X<lex_read_unichar>,
+lex_stuff_pvn X<lex_stuff_pvn>, lex_stuff_sv X<lex_stuff_sv>, lex_unstuff
+X<lex_unstuff>, PL_parser X<PL_parser>, PL_parser-E<gt>bufend
+X<PL_parser-E<gt>bufend>, PL_parser-E<gt>bufptr X<PL_parser-E<gt>bufptr>,
+PL_parser-E<gt>linestart X<PL_parser-E<gt>linestart>,
+PL_parser-E<gt>linestr X<PL_parser-E<gt>linestr>
+
+=item Magical Functions
+
+mg_clear X<mg_clear>, mg_copy X<mg_copy>, mg_find X<mg_find>, mg_free
+X<mg_free>, mg_get X<mg_get>, mg_length X<mg_length>, mg_magical
+X<mg_magical>, mg_set X<mg_set>, SvGETMAGIC X<SvGETMAGIC>, SvLOCK
+X<SvLOCK>, SvSETMAGIC X<SvSETMAGIC>, SvSetMagicSV X<SvSetMagicSV>,
+SvSetMagicSV_nosteal X<SvSetMagicSV_nosteal>, SvSetSV X<SvSetSV>,
+SvSetSV_nosteal X<SvSetSV_nosteal>, SvSHARE X<SvSHARE>, SvUNLOCK
+X<SvUNLOCK>
+
+=item Memory Management
+
+Copy X<Copy>, CopyD X<CopyD>, Move X<Move>, MoveD X<MoveD>, Newx X<Newx>,
+Newxc X<Newxc>, Newxz X<Newxz>, Poison X<Poison>, PoisonFree X<PoisonFree>,
+PoisonNew X<PoisonNew>, PoisonWith X<PoisonWith>, Renew X<Renew>, Renewc
+X<Renewc>, Safefree X<Safefree>, savepv X<savepv>, savepvn X<savepvn>,
+savepvs X<savepvs>, savesharedpv X<savesharedpv>, savesharedpvn
+X<savesharedpvn>, savesvpv X<savesvpv>, StructCopy X<StructCopy>, Zero
+X<Zero>, ZeroD X<ZeroD>
+
+=item Miscellaneous Functions
+
+fbm_compile X<fbm_compile>, fbm_instr X<fbm_instr>, form X<form>, getcwd_sv
+X<getcwd_sv>, my_snprintf X<my_snprintf>, my_sprintf X<my_sprintf>,
+my_vsnprintf X<my_vsnprintf>, new_version X<new_version>, prescan_version
+X<prescan_version>, scan_version X<scan_version>, strEQ X<strEQ>, strGE
+X<strGE>, strGT X<strGT>, strLE X<strLE>, strLT X<strLT>, strNE X<strNE>,
+strnEQ X<strnEQ>, strnNE X<strnNE>, sv_destroyable X<sv_destroyable>,
+sv_nosharing X<sv_nosharing>, upg_version X<upg_version>, vcmp X<vcmp>,
+vnormal X<vnormal>, vnumify X<vnumify>, vstringify X<vstringify>, vverify
+X<vverify>
+
+=item MRO Functions
+
+mro_get_linear_isa X<mro_get_linear_isa>, mro_method_changed_in
+X<mro_method_changed_in>
+
+=item Multicall Functions
+
+dMULTICALL X<dMULTICALL>, MULTICALL X<MULTICALL>, POP_MULTICALL
+X<POP_MULTICALL>, PUSH_MULTICALL X<PUSH_MULTICALL>
+
+=item Numeric functions
+
+grok_bin X<grok_bin>, grok_hex X<grok_hex>, grok_number X<grok_number>,
+grok_numeric_radix X<grok_numeric_radix>, grok_oct X<grok_oct>,
+Perl_signbit X<Perl_signbit>, scan_bin X<scan_bin>, scan_hex X<scan_hex>,
+scan_oct X<scan_oct>
+
+=item Optree Manipulation Functions
+
+cv_const_sv X<cv_const_sv>, newCONSTSUB X<newCONSTSUB>, newXS X<newXS>
+
+=item Pad Data Structures
+
+pad_findmy X<pad_findmy>, pad_sv X<pad_sv>
+
+=item Per-Interpreter Variables
+
+PL_modglobal X<PL_modglobal>, PL_na X<PL_na>, PL_opfreehook
+X<PL_opfreehook>, PL_sv_no X<PL_sv_no>, PL_sv_undef X<PL_sv_undef>,
+PL_sv_yes X<PL_sv_yes>
+
+=item REGEXP Functions
+
+SvRX X<SvRX>, SvRXOK X<SvRXOK>
+
+=item Simple Exception Handling Macros
+
+dXCPT X<dXCPT>, XCPT_CATCH X<XCPT_CATCH>, XCPT_RETHROW X<XCPT_RETHROW>,
+XCPT_TRY_END X<XCPT_TRY_END>, XCPT_TRY_START X<XCPT_TRY_START>
+
+=item Stack Manipulation Macros
+
+dMARK X<dMARK>, dORIGMARK X<dORIGMARK>, dSP X<dSP>, EXTEND X<EXTEND>, MARK
+X<MARK>, mPUSHi X<mPUSHi>, mPUSHn X<mPUSHn>, mPUSHp X<mPUSHp>, mPUSHs
+X<mPUSHs>, mPUSHu X<mPUSHu>, mXPUSHi X<mXPUSHi>, mXPUSHn X<mXPUSHn>,
+mXPUSHp X<mXPUSHp>, mXPUSHs X<mXPUSHs>, mXPUSHu X<mXPUSHu>, ORIGMARK
+X<ORIGMARK>, POPi X<POPi>, POPl X<POPl>, POPn X<POPn>, POPp X<POPp>,
+POPpbytex X<POPpbytex>, POPpx X<POPpx>, POPs X<POPs>, PUSHi X<PUSHi>,
+PUSHMARK X<PUSHMARK>, PUSHmortal X<PUSHmortal>, PUSHn X<PUSHn>, PUSHp
+X<PUSHp>, PUSHs X<PUSHs>, PUSHu X<PUSHu>, PUTBACK X<PUTBACK>, SP X<SP>,
+SPAGAIN X<SPAGAIN>, XPUSHi X<XPUSHi>, XPUSHmortal X<XPUSHmortal>, XPUSHn
+X<XPUSHn>, XPUSHp X<XPUSHp>, XPUSHs X<XPUSHs>, XPUSHu X<XPUSHu>, XSRETURN
+X<XSRETURN>, XSRETURN_EMPTY X<XSRETURN_EMPTY>, XSRETURN_IV X<XSRETURN_IV>,
+XSRETURN_NO X<XSRETURN_NO>, XSRETURN_NV X<XSRETURN_NV>, XSRETURN_PV
+X<XSRETURN_PV>, XSRETURN_UNDEF X<XSRETURN_UNDEF>, XSRETURN_UV
+X<XSRETURN_UV>, XSRETURN_YES X<XSRETURN_YES>, XST_mIV X<XST_mIV>, XST_mNO
+X<XST_mNO>, XST_mNV X<XST_mNV>, XST_mPV X<XST_mPV>, XST_mUNDEF
+X<XST_mUNDEF>, XST_mYES X<XST_mYES>
+
+=item SV Flags
+
+svtype X<svtype>, SVt_IV X<SVt_IV>, SVt_NV X<SVt_NV>, SVt_PV X<SVt_PV>,
+SVt_PVAV X<SVt_PVAV>, SVt_PVCV X<SVt_PVCV>, SVt_PVHV X<SVt_PVHV>, SVt_PVMG
+X<SVt_PVMG>
+
+=item SV Manipulation Functions
+
+croak_xs_usage X<croak_xs_usage>, get_sv X<get_sv>, newRV_inc X<newRV_inc>,
+newSVpvn_utf8 X<newSVpvn_utf8>, SvCUR X<SvCUR>, SvCUR_set X<SvCUR_set>,
+SvEND X<SvEND>, SvGAMAGIC X<SvGAMAGIC>, SvGROW X<SvGROW>, SvIOK X<SvIOK>,
+SvIOKp X<SvIOKp>, SvIOK_notUV X<SvIOK_notUV>, SvIOK_off X<SvIOK_off>,
+SvIOK_on X<SvIOK_on>, SvIOK_only X<SvIOK_only>, SvIOK_only_UV
+X<SvIOK_only_UV>, SvIOK_UV X<SvIOK_UV>, SvIsCOW X<SvIsCOW>,
+SvIsCOW_shared_hash X<SvIsCOW_shared_hash>, SvIV X<SvIV>, SvIVX X<SvIVX>,
+SvIVx X<SvIVx>, SvIV_nomg X<SvIV_nomg>, SvIV_set X<SvIV_set>, SvLEN
+X<SvLEN>, SvLEN_set X<SvLEN_set>, SvMAGIC_set X<SvMAGIC_set>, SvNIOK
+X<SvNIOK>, SvNIOKp X<SvNIOKp>, SvNIOK_off X<SvNIOK_off>, SvNOK X<SvNOK>,
+SvNOKp X<SvNOKp>, SvNOK_off X<SvNOK_off>, SvNOK_on X<SvNOK_on>, SvNOK_only
+X<SvNOK_only>, SvNV X<SvNV>, SvNVX X<SvNVX>, SvNVx X<SvNVx>, SvNV_set
+X<SvNV_set>, SvOK X<SvOK>, SvOOK X<SvOOK>, SvOOK_offset X<SvOOK_offset>,
+SvPOK X<SvPOK>, SvPOKp X<SvPOKp>, SvPOK_off X<SvPOK_off>, SvPOK_on
+X<SvPOK_on>, SvPOK_only X<SvPOK_only>, SvPOK_only_UTF8 X<SvPOK_only_UTF8>,
+SvPV X<SvPV>, SvPVbyte X<SvPVbyte>, SvPVbytex X<SvPVbytex>, SvPVbytex_force
+X<SvPVbytex_force>, SvPVbyte_force X<SvPVbyte_force>, SvPVbyte_nolen
+X<SvPVbyte_nolen>, SvPVutf8 X<SvPVutf8>, SvPVutf8x X<SvPVutf8x>,
+SvPVutf8x_force X<SvPVutf8x_force>, SvPVutf8_force X<SvPVutf8_force>,
+SvPVutf8_nolen X<SvPVutf8_nolen>, SvPVX X<SvPVX>, SvPVx X<SvPVx>,
+SvPV_force X<SvPV_force>, SvPV_force_nomg X<SvPV_force_nomg>, SvPV_nolen
+X<SvPV_nolen>, SvPV_nomg X<SvPV_nomg>, SvPV_set X<SvPV_set>, SvREFCNT
+X<SvREFCNT>, SvREFCNT_dec X<SvREFCNT_dec>, SvREFCNT_inc X<SvREFCNT_inc>,
+SvREFCNT_inc_NN X<SvREFCNT_inc_NN>, SvREFCNT_inc_simple
+X<SvREFCNT_inc_simple>, SvREFCNT_inc_simple_NN X<SvREFCNT_inc_simple_NN>,
+SvREFCNT_inc_simple_void X<SvREFCNT_inc_simple_void>,
+SvREFCNT_inc_simple_void_NN X<SvREFCNT_inc_simple_void_NN>,
+SvREFCNT_inc_void X<SvREFCNT_inc_void>, SvREFCNT_inc_void_NN
+X<SvREFCNT_inc_void_NN>, SvROK X<SvROK>, SvROK_off X<SvROK_off>, SvROK_on
+X<SvROK_on>, SvRV X<SvRV>, SvRV_set X<SvRV_set>, SvSTASH X<SvSTASH>,
+SvSTASH_set X<SvSTASH_set>, SvTAINT X<SvTAINT>, SvTAINTED X<SvTAINTED>,
+SvTAINTED_off X<SvTAINTED_off>, SvTAINTED_on X<SvTAINTED_on>, SvTRUE
+X<SvTRUE>, SvTYPE X<SvTYPE>, SvUOK X<SvUOK>, SvUPGRADE X<SvUPGRADE>, SvUTF8
+X<SvUTF8>, SvUTF8_off X<SvUTF8_off>, SvUTF8_on X<SvUTF8_on>, SvUV X<SvUV>,
+SvUVX X<SvUVX>, SvUVx X<SvUVx>, SvUV_nomg X<SvUV_nomg>, SvUV_set
+X<SvUV_set>, SvVOK X<SvVOK>, sv_catpvn_nomg X<sv_catpvn_nomg>,
+sv_catsv_nomg X<sv_catsv_nomg>, sv_derived_from X<sv_derived_from>, sv_does
+X<sv_does>, sv_report_used X<sv_report_used>, sv_setsv_nomg
+X<sv_setsv_nomg>, sv_utf8_upgrade_nomg X<sv_utf8_upgrade_nomg>
+
+=item SV-Body Allocation
+
+looks_like_number X<looks_like_number>, newRV_noinc X<newRV_noinc>, newSV
+X<newSV>, newSVhek X<newSVhek>, newSViv X<newSViv>, newSVnv X<newSVnv>,
+newSVpv X<newSVpv>, newSVpvf X<newSVpvf>, newSVpvn X<newSVpvn>,
+newSVpvn_flags X<newSVpvn_flags>, newSVpvn_share X<newSVpvn_share>,
+newSVpvs X<newSVpvs>, newSVpvs_flags X<newSVpvs_flags>, newSVpvs_share
+X<newSVpvs_share>, newSVrv X<newSVrv>, newSVsv X<newSVsv>, newSVuv
+X<newSVuv>, newSV_type X<newSV_type>, sv_2bool X<sv_2bool>, sv_2cv
+X<sv_2cv>, sv_2io X<sv_2io>, sv_2iv_flags X<sv_2iv_flags>, sv_2mortal
+X<sv_2mortal>, sv_2nv X<sv_2nv>, sv_2pvbyte X<sv_2pvbyte>, sv_2pvutf8
+X<sv_2pvutf8>, sv_2pv_flags X<sv_2pv_flags>, sv_2uv_flags X<sv_2uv_flags>,
+sv_backoff X<sv_backoff>, sv_bless X<sv_bless>, sv_catpv X<sv_catpv>,
+sv_catpvf X<sv_catpvf>, sv_catpvf_mg X<sv_catpvf_mg>, sv_catpvn
+X<sv_catpvn>, sv_catpvn_flags X<sv_catpvn_flags>, sv_catpvs X<sv_catpvs>,
+sv_catpv_mg X<sv_catpv_mg>, sv_catsv X<sv_catsv>, sv_catsv_flags
+X<sv_catsv_flags>, sv_chop X<sv_chop>, sv_clear X<sv_clear>, sv_cmp
+X<sv_cmp>, sv_cmp_locale X<sv_cmp_locale>, sv_collxfrm X<sv_collxfrm>,
+sv_copypv X<sv_copypv>, sv_dec X<sv_dec>, sv_eq X<sv_eq>,
+sv_force_normal_flags X<sv_force_normal_flags>, sv_free X<sv_free>, sv_gets
+X<sv_gets>, sv_grow X<sv_grow>, sv_inc X<sv_inc>, sv_insert X<sv_insert>,
+sv_insert_flags X<sv_insert_flags>, sv_isa X<sv_isa>, sv_isobject
+X<sv_isobject>, sv_len X<sv_len>, sv_len_utf8 X<sv_len_utf8>, sv_magic
+X<sv_magic>, sv_magicext X<sv_magicext>, sv_mortalcopy X<sv_mortalcopy>,
+sv_newmortal X<sv_newmortal>, sv_newref X<sv_newref>, sv_pos_b2u
+X<sv_pos_b2u>, sv_pos_u2b X<sv_pos_u2b>, sv_pos_u2b_flags
+X<sv_pos_u2b_flags>, sv_pvbyten_force X<sv_pvbyten_force>, sv_pvn_force
+X<sv_pvn_force>, sv_pvn_force_flags X<sv_pvn_force_flags>, sv_pvutf8n_force
+X<sv_pvutf8n_force>, sv_reftype X<sv_reftype>, sv_replace X<sv_replace>,
+sv_reset X<sv_reset>, sv_rvweaken X<sv_rvweaken>, sv_setiv X<sv_setiv>,
+sv_setiv_mg X<sv_setiv_mg>, sv_setnv X<sv_setnv>, sv_setnv_mg
+X<sv_setnv_mg>, sv_setpv X<sv_setpv>, sv_setpvf X<sv_setpvf>, sv_setpvf_mg
+X<sv_setpvf_mg>, sv_setpviv X<sv_setpviv>, sv_setpviv_mg X<sv_setpviv_mg>,
+sv_setpvn X<sv_setpvn>, sv_setpvn_mg X<sv_setpvn_mg>, sv_setpvs
+X<sv_setpvs>, sv_setpv_mg X<sv_setpv_mg>, sv_setref_iv X<sv_setref_iv>,
+sv_setref_nv X<sv_setref_nv>, sv_setref_pv X<sv_setref_pv>, sv_setref_pvn
+X<sv_setref_pvn>, sv_setref_uv X<sv_setref_uv>, sv_setsv X<sv_setsv>,
+sv_setsv_flags X<sv_setsv_flags>, sv_setsv_mg X<sv_setsv_mg>, sv_setuv
+X<sv_setuv>, sv_setuv_mg X<sv_setuv_mg>, sv_tainted X<sv_tainted>, sv_true
+X<sv_true>, sv_unmagic X<sv_unmagic>, sv_unref_flags X<sv_unref_flags>,
+sv_untaint X<sv_untaint>, sv_upgrade X<sv_upgrade>, sv_usepvn_flags
+X<sv_usepvn_flags>, sv_utf8_decode X<sv_utf8_decode>, sv_utf8_downgrade
+X<sv_utf8_downgrade>, sv_utf8_encode X<sv_utf8_encode>, sv_utf8_upgrade
+X<sv_utf8_upgrade>, sv_utf8_upgrade_flags X<sv_utf8_upgrade_flags>,
+sv_utf8_upgrade_nomg X<sv_utf8_upgrade_nomg>, sv_vcatpvf X<sv_vcatpvf>,
+sv_vcatpvfn X<sv_vcatpvfn>, sv_vcatpvf_mg X<sv_vcatpvf_mg>, sv_vsetpvf
+X<sv_vsetpvf>, sv_vsetpvfn X<sv_vsetpvfn>, sv_vsetpvf_mg X<sv_vsetpvf_mg>
+
+=item Unicode Support
+
+bytes_from_utf8 X<bytes_from_utf8>, bytes_to_utf8 X<bytes_to_utf8>,
+ibcmp_utf8 X<ibcmp_utf8>, is_ascii_string X<is_ascii_string>, is_utf8_char
+X<is_utf8_char>, is_utf8_string X<is_utf8_string>, is_utf8_string_loc
+X<is_utf8_string_loc>, is_utf8_string_loclen X<is_utf8_string_loclen>,
+pv_uni_display X<pv_uni_display>, sv_cat_decode X<sv_cat_decode>,
+sv_recode_to_utf8 X<sv_recode_to_utf8>, sv_uni_display X<sv_uni_display>,
+to_utf8_case X<to_utf8_case>, to_utf8_fold X<to_utf8_fold>, to_utf8_lower
+X<to_utf8_lower>, to_utf8_title X<to_utf8_title>, to_utf8_upper
+X<to_utf8_upper>, utf8n_to_uvchr X<utf8n_to_uvchr>, utf8n_to_uvuni
+X<utf8n_to_uvuni>, utf8_distance X<utf8_distance>, utf8_hop X<utf8_hop>,
+utf8_length X<utf8_length>, utf8_to_bytes X<utf8_to_bytes>, utf8_to_uvchr
+X<utf8_to_uvchr>, utf8_to_uvuni X<utf8_to_uvuni>, uvchr_to_utf8
+X<uvchr_to_utf8>, uvuni_to_utf8_flags X<uvuni_to_utf8_flags>
+
+=item Variables created by C<xsubpp> and C<xsubpp> internal functions
+
+ax X<ax>, CLASS X<CLASS>, dAX X<dAX>, dAXMARK X<dAXMARK>, dITEMS X<dITEMS>,
+dUNDERBAR X<dUNDERBAR>, dXSARGS X<dXSARGS>, dXSI32 X<dXSI32>, items
+X<items>, ix X<ix>, newXSproto X<newXSproto>, RETVAL X<RETVAL>, ST X<ST>,
+THIS X<THIS>, UNDERBAR X<UNDERBAR>, XS X<XS>, XS_VERSION X<XS_VERSION>,
+XS_VERSION_BOOTCHECK X<XS_VERSION_BOOTCHECK>
+
+=item Warning and Dieing
+
+croak X<croak>, warn X<warn>
+
+=item Undocumented functions
+
+GetVars X<GetVars>, Gv_AMupdate X<Gv_AMupdate>, PerlIO_clearerr
+X<PerlIO_clearerr>, PerlIO_close X<PerlIO_close>, PerlIO_context_layers
+X<PerlIO_context_layers>, PerlIO_eof X<PerlIO_eof>, PerlIO_error
+X<PerlIO_error>, PerlIO_fileno X<PerlIO_fileno>, PerlIO_fill
+X<PerlIO_fill>, PerlIO_flush X<PerlIO_flush>, PerlIO_get_base
+X<PerlIO_get_base>, PerlIO_get_bufsiz X<PerlIO_get_bufsiz>, PerlIO_get_cnt
+X<PerlIO_get_cnt>, PerlIO_get_ptr X<PerlIO_get_ptr>, PerlIO_read
+X<PerlIO_read>, PerlIO_seek X<PerlIO_seek>, PerlIO_set_cnt
+X<PerlIO_set_cnt>, PerlIO_set_ptrcnt X<PerlIO_set_ptrcnt>,
+PerlIO_setlinebuf X<PerlIO_setlinebuf>, PerlIO_stderr X<PerlIO_stderr>,
+PerlIO_stdin X<PerlIO_stdin>, PerlIO_stdout X<PerlIO_stdout>, PerlIO_tell
+X<PerlIO_tell>, PerlIO_unread X<PerlIO_unread>, PerlIO_write
+X<PerlIO_write>, Slab_Alloc X<Slab_Alloc>, Slab_Free X<Slab_Free>,
+amagic_call X<amagic_call>, any_dup X<any_dup>, apply_attrs_string
+X<apply_attrs_string>, atfork_lock X<atfork_lock>, atfork_unlock
+X<atfork_unlock>, av_arylen_p X<av_arylen_p>, av_iter_p X<av_iter_p>,
+block_gimme X<block_gimme>, call_atexit X<call_atexit>, call_list
+X<call_list>, calloc X<calloc>, cast_i32 X<cast_i32>, cast_iv X<cast_iv>,
+cast_ulong X<cast_ulong>, cast_uv X<cast_uv>, ck_warner X<ck_warner>,
+ck_warner_d X<ck_warner_d>, ckwarn X<ckwarn>, ckwarn_d X<ckwarn_d>,
+croak_nocontext X<croak_nocontext>, csighandler X<csighandler>,
+custom_op_desc X<custom_op_desc>, custom_op_name X<custom_op_name>, cx_dump
+X<cx_dump>, cx_dup X<cx_dup>, cxinc X<cxinc>, deb X<deb>, deb_nocontext
+X<deb_nocontext>, debop X<debop>, debprofdump X<debprofdump>, debstack
+X<debstack>, debstackptrs X<debstackptrs>, delimcpy X<delimcpy>,
+despatch_signals X<despatch_signals>, die X<die>, die_nocontext
+X<die_nocontext>, dirp_dup X<dirp_dup>, do_aspawn X<do_aspawn>, do_binmode
+X<do_binmode>, do_close X<do_close>, do_gv_dump X<do_gv_dump>, do_gvgv_dump
+X<do_gvgv_dump>, do_hv_dump X<do_hv_dump>, do_join X<do_join>,
+do_magic_dump X<do_magic_dump>, do_op_dump X<do_op_dump>, do_open
+X<do_open>, do_open9 X<do_open9>, do_openn X<do_openn>, do_pmop_dump
+X<do_pmop_dump>, do_spawn X<do_spawn>, do_spawn_nowait X<do_spawn_nowait>,
+do_sprintf X<do_sprintf>, do_sv_dump X<do_sv_dump>, doing_taint
+X<doing_taint>, doref X<doref>, dounwind X<dounwind>, dowantarray
+X<dowantarray>, dump_all X<dump_all>, dump_eval X<dump_eval>, dump_fds
+X<dump_fds>, dump_form X<dump_form>, dump_indent X<dump_indent>,
+dump_mstats X<dump_mstats>, dump_packsubs X<dump_packsubs>, dump_sub
+X<dump_sub>, dump_vindent X<dump_vindent>, fetch_cop_label
+X<fetch_cop_label>, filter_add X<filter_add>, filter_del X<filter_del>,
+filter_read X<filter_read>, find_rundefsvoffset X<find_rundefsvoffset>,
+form_nocontext X<form_nocontext>, fp_dup X<fp_dup>, fprintf_nocontext
+X<fprintf_nocontext>, free_global_struct X<free_global_struct>, free_tmps
+X<free_tmps>, get_context X<get_context>, get_mstats X<get_mstats>,
+get_op_descs X<get_op_descs>, get_op_names X<get_op_names>, get_ppaddr
+X<get_ppaddr>, get_vtbl X<get_vtbl>, gp_dup X<gp_dup>, gp_free X<gp_free>,
+gp_ref X<gp_ref>, gv_AVadd X<gv_AVadd>, gv_HVadd X<gv_HVadd>, gv_IOadd
+X<gv_IOadd>, gv_SVadd X<gv_SVadd>, gv_add_by_type X<gv_add_by_type>,
+gv_autoload4 X<gv_autoload4>, gv_check X<gv_check>, gv_dump X<gv_dump>,
+gv_efullname X<gv_efullname>, gv_efullname3 X<gv_efullname3>, gv_efullname4
+X<gv_efullname4>, gv_fetchfile X<gv_fetchfile>, gv_fetchfile_flags
+X<gv_fetchfile_flags>, gv_fetchmethod_flags X<gv_fetchmethod_flags>,
+gv_fetchpv X<gv_fetchpv>, gv_fetchpvn_flags X<gv_fetchpvn_flags>,
+gv_fetchsv X<gv_fetchsv>, gv_fullname X<gv_fullname>, gv_fullname3
+X<gv_fullname3>, gv_fullname4 X<gv_fullname4>, gv_handler X<gv_handler>,
+gv_init X<gv_init>, gv_name_set X<gv_name_set>, he_dup X<he_dup>, hek_dup
+X<hek_dup>, hv_common X<hv_common>, hv_common_key_len X<hv_common_key_len>,
+hv_delayfree_ent X<hv_delayfree_ent>, hv_eiter_p X<hv_eiter_p>,
+hv_eiter_set X<hv_eiter_set>, hv_free_ent X<hv_free_ent>, hv_ksplit
+X<hv_ksplit>, hv_name_set X<hv_name_set>, hv_placeholders_get
+X<hv_placeholders_get>, hv_placeholders_p X<hv_placeholders_p>,
+hv_placeholders_set X<hv_placeholders_set>, hv_riter_p X<hv_riter_p>,
+hv_riter_set X<hv_riter_set>, hv_store_flags X<hv_store_flags>, ibcmp
+X<ibcmp>, ibcmp_locale X<ibcmp_locale>, init_global_struct
+X<init_global_struct>, init_i18nl10n X<init_i18nl10n>, init_i18nl14n
+X<init_i18nl14n>, init_stacks X<init_stacks>, init_tm X<init_tm>, instr
+X<instr>, is_lvalue_sub X<is_lvalue_sub>, is_uni_alnum X<is_uni_alnum>,
+is_uni_alnum_lc X<is_uni_alnum_lc>, is_uni_alpha X<is_uni_alpha>,
+is_uni_alpha_lc X<is_uni_alpha_lc>, is_uni_ascii X<is_uni_ascii>,
+is_uni_ascii_lc X<is_uni_ascii_lc>, is_uni_cntrl X<is_uni_cntrl>,
+is_uni_cntrl_lc X<is_uni_cntrl_lc>, is_uni_digit X<is_uni_digit>,
+is_uni_digit_lc X<is_uni_digit_lc>, is_uni_graph X<is_uni_graph>,
+is_uni_graph_lc X<is_uni_graph_lc>, is_uni_idfirst X<is_uni_idfirst>,
+is_uni_idfirst_lc X<is_uni_idfirst_lc>, is_uni_lower X<is_uni_lower>,
+is_uni_lower_lc X<is_uni_lower_lc>, is_uni_print X<is_uni_print>,
+is_uni_print_lc X<is_uni_print_lc>, is_uni_punct X<is_uni_punct>,
+is_uni_punct_lc X<is_uni_punct_lc>, is_uni_space X<is_uni_space>,
+is_uni_space_lc X<is_uni_space_lc>, is_uni_upper X<is_uni_upper>,
+is_uni_upper_lc X<is_uni_upper_lc>, is_uni_xdigit X<is_uni_xdigit>,
+is_uni_xdigit_lc X<is_uni_xdigit_lc>, is_utf8_alnum X<is_utf8_alnum>,
+is_utf8_alpha X<is_utf8_alpha>, is_utf8_ascii X<is_utf8_ascii>,
+is_utf8_cntrl X<is_utf8_cntrl>, is_utf8_digit X<is_utf8_digit>,
+is_utf8_graph X<is_utf8_graph>, is_utf8_idcont X<is_utf8_idcont>,
+is_utf8_idfirst X<is_utf8_idfirst>, is_utf8_lower X<is_utf8_lower>,
+is_utf8_mark X<is_utf8_mark>, is_utf8_perl_space X<is_utf8_perl_space>,
+is_utf8_perl_word X<is_utf8_perl_word>, is_utf8_posix_digit
+X<is_utf8_posix_digit>, is_utf8_print X<is_utf8_print>, is_utf8_punct
+X<is_utf8_punct>, is_utf8_space X<is_utf8_space>, is_utf8_upper
+X<is_utf8_upper>, is_utf8_xdigit X<is_utf8_xdigit>, leave_scope
+X<leave_scope>, load_module_nocontext X<load_module_nocontext>, magic_dump
+X<magic_dump>, malloc X<malloc>, markstack_grow X<markstack_grow>, mess
+X<mess>, mess_nocontext X<mess_nocontext>, mfree X<mfree>, mg_dup
+X<mg_dup>, mg_size X<mg_size>, mini_mktime X<mini_mktime>, moreswitches
+X<moreswitches>, mro_get_from_name X<mro_get_from_name>,
+mro_get_private_data X<mro_get_private_data>, mro_register X<mro_register>,
+mro_set_mro X<mro_set_mro>, mro_set_private_data X<mro_set_private_data>,
+my_atof X<my_atof>, my_atof2 X<my_atof2>, my_bcopy X<my_bcopy>, my_bzero
+X<my_bzero>, my_chsize X<my_chsize>, my_cxt_index X<my_cxt_index>,
+my_cxt_init X<my_cxt_init>, my_dirfd X<my_dirfd>, my_exit X<my_exit>,
+my_failure_exit X<my_failure_exit>, my_fflush_all X<my_fflush_all>, my_fork
+X<my_fork>, my_htonl X<my_htonl>, my_lstat X<my_lstat>, my_memcmp
+X<my_memcmp>, my_memset X<my_memset>, my_ntohl X<my_ntohl>, my_pclose
+X<my_pclose>, my_popen X<my_popen>, my_popen_list X<my_popen_list>,
+my_setenv X<my_setenv>, my_socketpair X<my_socketpair>, my_stat X<my_stat>,
+my_strftime X<my_strftime>, my_strlcat X<my_strlcat>, my_strlcpy
+X<my_strlcpy>, my_swap X<my_swap>, newANONATTRSUB X<newANONATTRSUB>,
+newANONHASH X<newANONHASH>, newANONLIST X<newANONLIST>, newANONSUB
+X<newANONSUB>, newASSIGNOP X<newASSIGNOP>, newATTRSUB X<newATTRSUB>,
+newAVREF X<newAVREF>, newBINOP X<newBINOP>, newCONDOP X<newCONDOP>,
+newCVREF X<newCVREF>, newFORM X<newFORM>, newFOROP X<newFOROP>, newGIVENOP
+X<newGIVENOP>, newGVOP X<newGVOP>, newGVREF X<newGVREF>, newGVgen
+X<newGVgen>, newHVREF X<newHVREF>, newHVhv X<newHVhv>, newIO X<newIO>,
+newLISTOP X<newLISTOP>, newLOGOP X<newLOGOP>, newLOOPEX X<newLOOPEX>,
+newLOOPOP X<newLOOPOP>, newMYSUB X<newMYSUB>, newNULLLIST X<newNULLLIST>,
+newOP X<newOP>, newPADOP X<newPADOP>, newPMOP X<newPMOP>, newPROG
+X<newPROG>, newPVOP X<newPVOP>, newRANGE X<newRANGE>, newRV X<newRV>,
+newSLICEOP X<newSLICEOP>, newSTATEOP X<newSTATEOP>, newSUB X<newSUB>,
+newSVOP X<newSVOP>, newSVREF X<newSVREF>, newSVpvf_nocontext
+X<newSVpvf_nocontext>, newUNOP X<newUNOP>, newWHENOP X<newWHENOP>,
+newWHILEOP X<newWHILEOP>, newXS_flags X<newXS_flags>, new_collate
+X<new_collate>, new_ctype X<new_ctype>, new_numeric X<new_numeric>,
+new_stackinfo X<new_stackinfo>, ninstr X<ninstr>, op_dump X<op_dump>,
+op_free X<op_free>, op_null X<op_null>, op_refcnt_lock X<op_refcnt_lock>,
+op_refcnt_unlock X<op_refcnt_unlock>, parser_dup X<parser_dup>,
+perl_alloc_using X<perl_alloc_using>, perl_clone_using X<perl_clone_using>,
+pmop_dump X<pmop_dump>, pop_scope X<pop_scope>, pregcomp X<pregcomp>,
+pregexec X<pregexec>, pregfree X<pregfree>, pregfree2 X<pregfree2>,
+printf_nocontext X<printf_nocontext>, ptr_table_clear X<ptr_table_clear>,
+ptr_table_fetch X<ptr_table_fetch>, ptr_table_free X<ptr_table_free>,
+ptr_table_new X<ptr_table_new>, ptr_table_split X<ptr_table_split>,
+ptr_table_store X<ptr_table_store>, push_scope X<push_scope>, re_compile
+X<re_compile>, re_dup_guts X<re_dup_guts>, re_intuit_start
+X<re_intuit_start>, re_intuit_string X<re_intuit_string>, realloc
+X<realloc>, reentrant_free X<reentrant_free>, reentrant_init
+X<reentrant_init>, reentrant_retry X<reentrant_retry>, reentrant_size
+X<reentrant_size>, ref X<ref>, reg_named_buff_all X<reg_named_buff_all>,
+reg_named_buff_exists X<reg_named_buff_exists>, reg_named_buff_fetch
+X<reg_named_buff_fetch>, reg_named_buff_firstkey
+X<reg_named_buff_firstkey>, reg_named_buff_nextkey
+X<reg_named_buff_nextkey>, reg_named_buff_scalar X<reg_named_buff_scalar>,
+regclass_swash X<regclass_swash>, regdump X<regdump>, regdupe_internal
+X<regdupe_internal>, regexec_flags X<regexec_flags>, regfree_internal
+X<regfree_internal>, reginitcolors X<reginitcolors>, regnext X<regnext>,
+repeatcpy X<repeatcpy>, rninstr X<rninstr>, rsignal X<rsignal>,
+rsignal_state X<rsignal_state>, runops_debug X<runops_debug>,
+runops_standard X<runops_standard>, rvpv_dup X<rvpv_dup>, safesyscalloc
+X<safesyscalloc>, safesysfree X<safesysfree>, safesysmalloc
+X<safesysmalloc>, safesysrealloc X<safesysrealloc>, save_I16 X<save_I16>,
+save_I32 X<save_I32>, save_I8 X<save_I8>, save_adelete X<save_adelete>,
+save_aelem X<save_aelem>, save_aelem_flags X<save_aelem_flags>, save_alloc
+X<save_alloc>, save_aptr X<save_aptr>, save_ary X<save_ary>, save_bool
+X<save_bool>, save_clearsv X<save_clearsv>, save_delete X<save_delete>,
+save_destructor X<save_destructor>, save_destructor_x X<save_destructor_x>,
+save_freepv X<save_freepv>, save_freesv X<save_freesv>, save_generic_pvref
+X<save_generic_pvref>, save_generic_svref X<save_generic_svref>, save_gp
+X<save_gp>, save_hash X<save_hash>, save_hdelete X<save_hdelete>,
+save_helem X<save_helem>, save_helem_flags X<save_helem_flags>, save_hptr
+X<save_hptr>, save_int X<save_int>, save_item X<save_item>, save_iv
+X<save_iv>, save_list X<save_list>, save_long X<save_long>,
+save_mortalizesv X<save_mortalizesv>, save_nogv X<save_nogv>,
+save_padsv_and_mortalize X<save_padsv_and_mortalize>, save_pptr
+X<save_pptr>, save_pushptr X<save_pushptr>, save_re_context
+X<save_re_context>, save_scalar X<save_scalar>, save_set_svflags
+X<save_set_svflags>, save_shared_pvref X<save_shared_pvref>, save_sptr
+X<save_sptr>, save_svref X<save_svref>, save_vptr X<save_vptr>,
+savestack_grow X<savestack_grow>, savestack_grow_cnt X<savestack_grow_cnt>,
+scan_num X<scan_num>, scan_vstring X<scan_vstring>, screaminstr
+X<screaminstr>, seed X<seed>, set_context X<set_context>, set_numeric_local
+X<set_numeric_local>, set_numeric_radix X<set_numeric_radix>,
+set_numeric_standard X<set_numeric_standard>, share_hek X<share_hek>,
+si_dup X<si_dup>, ss_dup X<ss_dup>, stack_grow X<stack_grow>,
+start_subparse X<start_subparse>, stashpv_hvname_match
+X<stashpv_hvname_match>, str_to_version X<str_to_version>, sv_2iv
+X<sv_2iv>, sv_2pv X<sv_2pv>, sv_2uv X<sv_2uv>, sv_catpvf_mg_nocontext
+X<sv_catpvf_mg_nocontext>, sv_catpvf_nocontext X<sv_catpvf_nocontext>,
+sv_compile_2op X<sv_compile_2op>, sv_dump X<sv_dump>, sv_dup X<sv_dup>,
+sv_peek X<sv_peek>, sv_pvn_nomg X<sv_pvn_nomg>, sv_setpvf_mg_nocontext
+X<sv_setpvf_mg_nocontext>, sv_setpvf_nocontext X<sv_setpvf_nocontext>,
+sv_utf8_upgrade_flags_grow X<sv_utf8_upgrade_flags_grow>, swash_fetch
+X<swash_fetch>, swash_init X<swash_init>, sys_init X<sys_init>, sys_init3
+X<sys_init3>, sys_intern_clear X<sys_intern_clear>, sys_intern_dup
+X<sys_intern_dup>, sys_intern_init X<sys_intern_init>, sys_term
+X<sys_term>, taint_env X<taint_env>, taint_proper X<taint_proper>,
+tmps_grow X<tmps_grow>, to_uni_fold X<to_uni_fold>, to_uni_lower
+X<to_uni_lower>, to_uni_lower_lc X<to_uni_lower_lc>, to_uni_title
+X<to_uni_title>, to_uni_title_lc X<to_uni_title_lc>, to_uni_upper
+X<to_uni_upper>, to_uni_upper_lc X<to_uni_upper_lc>, unlnk X<unlnk>,
+unsharepvn X<unsharepvn>, utf16_to_utf8 X<utf16_to_utf8>,
+utf16_to_utf8_reversed X<utf16_to_utf8_reversed>, uvchr_to_utf8_flags
+X<uvchr_to_utf8_flags>, uvuni_to_utf8 X<uvuni_to_utf8>, vcroak X<vcroak>,
+vdeb X<vdeb>, vform X<vform>, vload_module X<vload_module>, vmess X<vmess>,
+vnewSVpvf X<vnewSVpvf>, vwarn X<vwarn>, vwarner X<vwarner>, warn_nocontext
+X<warn_nocontext>, warner X<warner>, warner_nocontext X<warner_nocontext>,
+whichsig X<whichsig>
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 perlintern - autogenerated documentation of purely B<internal>
+ Perl functions
+
+=over 4
+
+=item DESCRIPTION
+X<internal Perl functions> X<interpreter functions>
+
+=item CV reference counts and CvOUTSIDE
+
+CvWEAKOUTSIDE X<CvWEAKOUTSIDE>
+
+=item Functions in file pad.h
+
+CX_CURPAD_SAVE X<CX_CURPAD_SAVE>, CX_CURPAD_SV X<CX_CURPAD_SV>, PAD_BASE_SV
+X<PAD_BASE_SV>, PAD_CLONE_VARS X<PAD_CLONE_VARS>, PAD_COMPNAME_FLAGS
+X<PAD_COMPNAME_FLAGS>, PAD_COMPNAME_GEN X<PAD_COMPNAME_GEN>,
+PAD_COMPNAME_GEN_set X<PAD_COMPNAME_GEN_set>, PAD_COMPNAME_OURSTASH
+X<PAD_COMPNAME_OURSTASH>, PAD_COMPNAME_PV X<PAD_COMPNAME_PV>,
+PAD_COMPNAME_TYPE X<PAD_COMPNAME_TYPE>, PAD_DUP X<PAD_DUP>,
+PAD_RESTORE_LOCAL X<PAD_RESTORE_LOCAL>, PAD_SAVE_LOCAL X<PAD_SAVE_LOCAL>,
+PAD_SAVE_SETNULLPAD X<PAD_SAVE_SETNULLPAD>, PAD_SETSV X<PAD_SETSV>,
+PAD_SET_CUR X<PAD_SET_CUR>, PAD_SET_CUR_NOSAVE X<PAD_SET_CUR_NOSAVE>,
+PAD_SV X<PAD_SV>, PAD_SVl X<PAD_SVl>, SAVECLEARSV X<SAVECLEARSV>,
+SAVECOMPPAD X<SAVECOMPPAD>, SAVEPADSV X<SAVEPADSV>
+
+=item Functions in file pp_ctl.c
+
+docatch X<docatch>
+
+=item GV Functions
+
+gv_try_downgrade X<gv_try_downgrade>, is_gv_magical_sv X<is_gv_magical_sv>
+
+=item Hash Manipulation Functions
+
+refcounted_he_chain_2hv X<refcounted_he_chain_2hv>, refcounted_he_free
+X<refcounted_he_free>, refcounted_he_new X<refcounted_he_new>
+
+=item IO Functions
+
+start_glob X<start_glob>
+
+=item Magical Functions
+
+magic_clearhint X<magic_clearhint>, magic_clearhints X<magic_clearhints>,
+magic_sethint X<magic_sethint>, mg_localize X<mg_localize>
+
+=item MRO Functions
+
+mro_get_linear_isa_dfs X<mro_get_linear_isa_dfs>, mro_isa_changed_in
+X<mro_isa_changed_in>
+
+=item Pad Data Structures
+
+CvPADLIST X<CvPADLIST>, cv_clone X<cv_clone>, cv_dump X<cv_dump>,
+do_dump_pad X<do_dump_pad>, intro_my X<intro_my>, pad_add_anon
+X<pad_add_anon>, pad_add_name X<pad_add_name>, pad_alloc X<pad_alloc>,
+pad_block_start X<pad_block_start>, pad_check_dup X<pad_check_dup>,
+pad_findlex X<pad_findlex>, pad_fixup_inner_anons X<pad_fixup_inner_anons>,
+pad_free X<pad_free>, pad_leavemy X<pad_leavemy>, pad_new X<pad_new>,
+pad_push X<pad_push>, pad_reset X<pad_reset>, pad_setsv X<pad_setsv>,
+pad_swipe X<pad_swipe>, pad_tidy X<pad_tidy>, pad_undef X<pad_undef>
+
+=item Per-Interpreter Variables
+
+PL_DBsingle X<PL_DBsingle>, PL_DBsub X<PL_DBsub>, PL_DBtrace X<PL_DBtrace>,
+PL_dowarn X<PL_dowarn>, PL_last_in_gv X<PL_last_in_gv>, PL_ofsgv
+X<PL_ofsgv>, PL_rs X<PL_rs>
+
+=item Stack Manipulation Macros
+
+djSP X<djSP>, LVRET X<LVRET>
+
+=item SV Manipulation Functions
+
+sv_add_arena X<sv_add_arena>, sv_clean_all X<sv_clean_all>, sv_clean_objs
+X<sv_clean_objs>, sv_free_arenas X<sv_free_arenas>
+
+=item SV-Body Allocation
+
+sv_2num X<sv_2num>
+
+=item Unicode Support
+
+find_uninit_var X<find_uninit_var>, report_uninit X<report_uninit>
+
+=item Undocumented functions
+
+F0convert X<F0convert>, Slab_to_rw X<Slab_to_rw>, add_data X<add_data>,
+add_utf16_textfilter X<add_utf16_textfilter>, addmad X<addmad>, allocmy
+X<allocmy>, amagic_cmp X<amagic_cmp>, amagic_cmp_locale
+X<amagic_cmp_locale>, amagic_i_ncmp X<amagic_i_ncmp>, amagic_ncmp
+X<amagic_ncmp>, anonymise_cv X<anonymise_cv>, ao X<ao>, append_elem
+X<append_elem>, append_list X<append_list>, append_madprops
+X<append_madprops>, apply X<apply>, apply_attrs X<apply_attrs>,
+apply_attrs_my X<apply_attrs_my>, av_reify X<av_reify>, bad_type
+X<bad_type>, bind_match X<bind_match>, block_end X<block_end>, block_start
+X<block_start>, boot_core_PerlIO X<boot_core_PerlIO>, boot_core_UNIVERSAL
+X<boot_core_UNIVERSAL>, boot_core_mro X<boot_core_mro>, bytes_to_uni
+X<bytes_to_uni>, cando X<cando>, check_type_and_open
+X<check_type_and_open>, check_uni X<check_uni>, checkcomma X<checkcomma>,
+checkposixcc X<checkposixcc>, ck_anoncode X<ck_anoncode>, ck_bitop
+X<ck_bitop>, ck_concat X<ck_concat>, ck_defined X<ck_defined>, ck_delete
+X<ck_delete>, ck_die X<ck_die>, ck_each X<ck_each>, ck_eof X<ck_eof>,
+ck_eval X<ck_eval>, ck_exec X<ck_exec>, ck_exists X<ck_exists>, ck_exit
+X<ck_exit>, ck_ftst X<ck_ftst>, ck_fun X<ck_fun>, ck_glob X<ck_glob>,
+ck_grep X<ck_grep>, ck_index X<ck_index>, ck_join X<ck_join>, ck_lfun
+X<ck_lfun>, ck_listiob X<ck_listiob>, ck_match X<ck_match>, ck_method
+X<ck_method>, ck_null X<ck_null>, ck_open X<ck_open>, ck_readline
+X<ck_readline>, ck_repeat X<ck_repeat>, ck_require X<ck_require>, ck_return
+X<ck_return>, ck_rfun X<ck_rfun>, ck_rvconst X<ck_rvconst>, ck_sassign
+X<ck_sassign>, ck_select X<ck_select>, ck_shift X<ck_shift>, ck_sort
+X<ck_sort>, ck_spair X<ck_spair>, ck_split X<ck_split>, ck_subr X<ck_subr>,
+ck_substr X<ck_substr>, ck_svconst X<ck_svconst>, ck_trunc X<ck_trunc>,
+ck_unpack X<ck_unpack>, ckwarn_common X<ckwarn_common>, cl_and X<cl_and>,
+cl_anything X<cl_anything>, cl_init X<cl_init>, cl_init_zero
+X<cl_init_zero>, cl_is_anything X<cl_is_anything>, cl_or X<cl_or>,
+clear_placeholders X<clear_placeholders>, closest_cop X<closest_cop>,
+convert X<convert>, cop_free X<cop_free>, cr_textfilter X<cr_textfilter>,
+create_eval_scope X<create_eval_scope>, curmad X<curmad>, cv_ckproto_len
+X<cv_ckproto_len>, deb_curcv X<deb_curcv>, deb_stack_all X<deb_stack_all>,
+deb_stack_n X<deb_stack_n>, debprof X<debprof>, debug_start_match
+X<debug_start_match>, del_sv X<del_sv>, delete_eval_scope
+X<delete_eval_scope>, deprecate_commaless_var_list
+X<deprecate_commaless_var_list>, destroy_matcher X<destroy_matcher>,
+die_where X<die_where>, div128 X<div128>, do_aexec X<do_aexec>, do_aexec5
+X<do_aexec5>, do_chomp X<do_chomp>, do_chop X<do_chop>, do_delete_local
+X<do_delete_local>, do_eof X<do_eof>, do_exec X<do_exec>, do_exec3
+X<do_exec3>, do_execfree X<do_execfree>, do_ipcctl X<do_ipcctl>, do_ipcget
+X<do_ipcget>, do_kv X<do_kv>, do_msgrcv X<do_msgrcv>, do_msgsnd
+X<do_msgsnd>, do_oddball X<do_oddball>, do_op_xmldump X<do_op_xmldump>,
+do_pmop_xmldump X<do_pmop_xmldump>, do_print X<do_print>, do_readline
+X<do_readline>, do_seek X<do_seek>, do_semop X<do_semop>, do_shmio
+X<do_shmio>, do_smartmatch X<do_smartmatch>, do_sysseek X<do_sysseek>,
+do_tell X<do_tell>, do_trans X<do_trans>, do_trans_complex
+X<do_trans_complex>, do_trans_complex_utf8 X<do_trans_complex_utf8>,
+do_trans_count X<do_trans_count>, do_trans_count_utf8
+X<do_trans_count_utf8>, do_trans_simple X<do_trans_simple>,
+do_trans_simple_utf8 X<do_trans_simple_utf8>, do_vecget X<do_vecget>,
+do_vecset X<do_vecset>, do_vop X<do_vop>, doeval X<doeval>, dofile
+X<dofile>, dofindlabel X<dofindlabel>, doform X<doform>, dooneliner
+X<dooneliner>, doopen_pm X<doopen_pm>, doparseform X<doparseform>,
+dopoptoeval X<dopoptoeval>, dopoptogiven X<dopoptogiven>, dopoptolabel
+X<dopoptolabel>, dopoptoloop X<dopoptoloop>, dopoptosub_at
+X<dopoptosub_at>, dopoptowhen X<dopoptowhen>, dump_all_perl
+X<dump_all_perl>, dump_exec_pos X<dump_exec_pos>, dump_packsubs_perl
+X<dump_packsubs_perl>, dump_sub_perl X<dump_sub_perl>, dump_sv_child
+X<dump_sv_child>, dump_trie X<dump_trie>, dump_trie_interim_list
+X<dump_trie_interim_list>, dump_trie_interim_table
+X<dump_trie_interim_table>, dumpuntil X<dumpuntil>, dup_attrlist
+X<dup_attrlist>, emulate_cop_io X<emulate_cop_io>, exec_failed
+X<exec_failed>, expect_number X<expect_number>, feature_is_enabled
+X<feature_is_enabled>, filter_gets X<filter_gets>, find_and_forget_pmops
+X<find_and_forget_pmops>, find_array_subscript X<find_array_subscript>,
+find_beginning X<find_beginning>, find_byclass X<find_byclass>,
+find_hash_subscript X<find_hash_subscript>, find_in_my_stash
+X<find_in_my_stash>, find_script X<find_script>, first_symbol
+X<first_symbol>, fold_constants X<fold_constants>, forbid_setid
+X<forbid_setid>, force_ident X<force_ident>, force_list X<force_list>,
+force_next X<force_next>, force_strict_version X<force_strict_version>,
+force_version X<force_version>, force_word X<force_word>, forget_pmop
+X<forget_pmop>, free_tied_hv_pool X<free_tied_hv_pool>, gen_constant_list
+X<gen_constant_list>, get_arena X<get_arena>, get_aux_mg X<get_aux_mg>,
+get_db_sub X<get_db_sub>, get_debug_opts X<get_debug_opts>, get_hash_seed
+X<get_hash_seed>, get_isa_hash X<get_isa_hash>, get_no_modify
+X<get_no_modify>, get_num X<get_num>, get_opargs X<get_opargs>, get_re_arg
+X<get_re_arg>, getenv_len X<getenv_len>, glob_2number X<glob_2number>,
+glob_assign_glob X<glob_assign_glob>, glob_assign_ref X<glob_assign_ref>,
+group_end X<group_end>, gv_ename X<gv_ename>, gv_get_super_pkg
+X<gv_get_super_pkg>, gv_init_sv X<gv_init_sv>, hfreeentries
+X<hfreeentries>, hsplit X<hsplit>, hv_auxinit X<hv_auxinit>,
+hv_backreferences_p X<hv_backreferences_p>, hv_copy_hints_hv
+X<hv_copy_hints_hv>, hv_delete_common X<hv_delete_common>, hv_kill_backrefs
+X<hv_kill_backrefs>, hv_magic_check X<hv_magic_check>, hv_notallowed
+X<hv_notallowed>, incline X<incline>, incpush X<incpush>, incpush_if_exists
+X<incpush_if_exists>, incpush_use_sep X<incpush_use_sep>, ingroup
+X<ingroup>, init_argv_symbols X<init_argv_symbols>, init_dbargs
+X<init_dbargs>, init_debugger X<init_debugger>, init_ids X<init_ids>,
+init_interp X<init_interp>, init_main_stash X<init_main_stash>,
+init_perllib X<init_perllib>, init_postdump_symbols
+X<init_postdump_symbols>, init_predump_symbols X<init_predump_symbols>,
+intuit_method X<intuit_method>, intuit_more X<intuit_more>, invert
+X<invert>, io_close X<io_close>, is_an_int X<is_an_int>,
+is_handle_constructor X<is_handle_constructor>, is_inplace_av
+X<is_inplace_av>, is_list_assignment X<is_list_assignment>, is_utf8_X_L
+X<is_utf8_X_L>, is_utf8_X_LV X<is_utf8_X_LV>, is_utf8_X_LVT
+X<is_utf8_X_LVT>, is_utf8_X_LV_LVT_V X<is_utf8_X_LV_LVT_V>, is_utf8_X_T
+X<is_utf8_X_T>, is_utf8_X_V X<is_utf8_X_V>, is_utf8_X_begin
+X<is_utf8_X_begin>, is_utf8_X_extend X<is_utf8_X_extend>,
+is_utf8_X_non_hangul X<is_utf8_X_non_hangul>, is_utf8_X_prepend
+X<is_utf8_X_prepend>, is_utf8_char_slow X<is_utf8_char_slow>,
+is_utf8_common X<is_utf8_common>, isa_lookup X<isa_lookup>, jmaybe
+X<jmaybe>, join_exact X<join_exact>, keyword X<keyword>,
+keyword_plugin_standard X<keyword_plugin_standard>, lex_end X<lex_end>,
+lex_start X<lex_start>, linklist X<linklist>, list X<list>, listkids
+X<listkids>, localize X<localize>, looks_like_bool X<looks_like_bool>, lop
+X<lop>, mad_free X<mad_free>, madlex X<madlex>, madparse X<madparse>,
+magic_clear_all_env X<magic_clear_all_env>, magic_clearenv
+X<magic_clearenv>, magic_clearisa X<magic_clearisa>, magic_clearpack
+X<magic_clearpack>, magic_clearsig X<magic_clearsig>, magic_existspack
+X<magic_existspack>, magic_freearylen_p X<magic_freearylen_p>,
+magic_freeovrld X<magic_freeovrld>, magic_get X<magic_get>, magic_getarylen
+X<magic_getarylen>, magic_getdefelem X<magic_getdefelem>, magic_getnkeys
+X<magic_getnkeys>, magic_getpack X<magic_getpack>, magic_getpos
+X<magic_getpos>, magic_getsig X<magic_getsig>, magic_getsubstr
+X<magic_getsubstr>, magic_gettaint X<magic_gettaint>, magic_getuvar
+X<magic_getuvar>, magic_getvec X<magic_getvec>, magic_killbackrefs
+X<magic_killbackrefs>, magic_len X<magic_len>, magic_methcall
+X<magic_methcall>, magic_methpack X<magic_methpack>, magic_nextpack
+X<magic_nextpack>, magic_regdata_cnt X<magic_regdata_cnt>,
+magic_regdatum_get X<magic_regdatum_get>, magic_regdatum_set
+X<magic_regdatum_set>, magic_scalarpack X<magic_scalarpack>, magic_set
+X<magic_set>, magic_set_all_env X<magic_set_all_env>, magic_setamagic
+X<magic_setamagic>, magic_setarylen X<magic_setarylen>, magic_setcollxfrm
+X<magic_setcollxfrm>, magic_setdbline X<magic_setdbline>, magic_setdefelem
+X<magic_setdefelem>, magic_setenv X<magic_setenv>, magic_setisa
+X<magic_setisa>, magic_setmglob X<magic_setmglob>, magic_setnkeys
+X<magic_setnkeys>, magic_setpack X<magic_setpack>, magic_setpos
+X<magic_setpos>, magic_setregexp X<magic_setregexp>, magic_setsig
+X<magic_setsig>, magic_setsubstr X<magic_setsubstr>, magic_settaint
+X<magic_settaint>, magic_setutf8 X<magic_setutf8>, magic_setuvar
+X<magic_setuvar>, magic_setvec X<magic_setvec>, magic_sizepack
+X<magic_sizepack>, magic_wipepack X<magic_wipepack>, make_matcher
+X<make_matcher>, make_trie X<make_trie>, make_trie_failtable
+X<make_trie_failtable>, malloc_good_size X<malloc_good_size>, malloced_size
+X<malloced_size>, matcher_matches_sv X<matcher_matches_sv>, measure_struct
+X<measure_struct>, mem_collxfrm X<mem_collxfrm>, mem_log_common
+X<mem_log_common>, mess_alloc X<mess_alloc>, method_common
+X<method_common>, missingterm X<missingterm>, mod X<mod>,
+mode_from_discipline X<mode_from_discipline>, modkids X<modkids>,
+more_bodies X<more_bodies>, more_sv X<more_sv>, mro_meta_dup
+X<mro_meta_dup>, mro_meta_init X<mro_meta_init>, mul128 X<mul128>, mulexp10
+X<mulexp10>, my_attrs X<my_attrs>, my_betoh16 X<my_betoh16>, my_betoh32
+X<my_betoh32>, my_betoh64 X<my_betoh64>, my_betohi X<my_betohi>, my_betohl
+X<my_betohl>, my_betohs X<my_betohs>, my_clearenv X<my_clearenv>,
+my_exit_jump X<my_exit_jump>, my_htobe16 X<my_htobe16>, my_htobe32
+X<my_htobe32>, my_htobe64 X<my_htobe64>, my_htobei X<my_htobei>, my_htobel
+X<my_htobel>, my_htobes X<my_htobes>, my_htole16 X<my_htole16>, my_htole32
+X<my_htole32>, my_htole64 X<my_htole64>, my_htolei X<my_htolei>, my_htolel
+X<my_htolel>, my_htoles X<my_htoles>, my_kid X<my_kid>, my_letoh16
+X<my_letoh16>, my_letoh32 X<my_letoh32>, my_letoh64 X<my_letoh64>,
+my_letohi X<my_letohi>, my_letohl X<my_letohl>, my_letohs X<my_letohs>,
+my_swabn X<my_swabn>, my_unexec X<my_unexec>, need_utf8 X<need_utf8>,
+newDEFSVOP X<newDEFSVOP>, newGIVWHENOP X<newGIVWHENOP>, newGP X<newGP>,
+newMADPROP X<newMADPROP>, newMADsv X<newMADsv>, newTOKEN X<newTOKEN>,
+new_constant X<new_constant>, new_he X<new_he>, new_logop X<new_logop>,
+new_warnings_bitfield X<new_warnings_bitfield>, next_symbol X<next_symbol>,
+nextargv X<nextargv>, nextchar X<nextchar>, no_bareword_allowed
+X<no_bareword_allowed>, no_fh_allowed X<no_fh_allowed>, no_op X<no_op>,
+not_a_number X<not_a_number>, nuke_stacks X<nuke_stacks>, num_overflow
+X<num_overflow>, offer_nice_chunk X<offer_nice_chunk>, oopsAV X<oopsAV>,
+oopsHV X<oopsHV>, op_clear X<op_clear>, op_const_sv X<op_const_sv>,
+op_getmad X<op_getmad>, op_getmad_weak X<op_getmad_weak>, op_refcnt_dec
+X<op_refcnt_dec>, op_refcnt_inc X<op_refcnt_inc>, op_xmldump X<op_xmldump>,
+open_script X<open_script>, opt_scalarhv X<opt_scalarhv>, pack_rec
+X<pack_rec>, package X<package>, package_version X<package_version>,
+pad_add_name_sv X<pad_add_name_sv>, pad_compname_type X<pad_compname_type>,
+pad_peg X<pad_peg>, parse_body X<parse_body>, parse_unicode_opts
+X<parse_unicode_opts>, parser_free X<parser_free>, path_is_absolute
+X<path_is_absolute>, peep X<peep>, pending_Slabs_to_ro
+X<pending_Slabs_to_ro>, pidgone X<pidgone>, pm_description
+X<pm_description>, pmflag X<pmflag>, pmop_xmldump X<pmop_xmldump>,
+pmruntime X<pmruntime>, pmtrans X<pmtrans>, prepend_elem X<prepend_elem>,
+prepend_madprops X<prepend_madprops>, printbuf X<printbuf>,
+process_special_blocks X<process_special_blocks>, ptr_table_find
+X<ptr_table_find>, put_byte X<put_byte>, qerror X<qerror>, qsortsvu
+X<qsortsvu>, re_croak2 X<re_croak2>, readpipe_override
+X<readpipe_override>, ref_array_or_hash X<ref_array_or_hash>,
+refcounted_he_fetch X<refcounted_he_fetch>, refcounted_he_new_common
+X<refcounted_he_new_common>, refcounted_he_value X<refcounted_he_value>,
+refkids X<refkids>, refto X<refto>, reg X<reg>,
+reg_check_named_buff_matched X<reg_check_named_buff_matched>,
+reg_named_buff X<reg_named_buff>, reg_named_buff_iter
+X<reg_named_buff_iter>, reg_namedseq X<reg_namedseq>, reg_node X<reg_node>,
+reg_numbered_buff_fetch X<reg_numbered_buff_fetch>,
+reg_numbered_buff_length X<reg_numbered_buff_length>,
+reg_numbered_buff_store X<reg_numbered_buff_store>, reg_qr_package
+X<reg_qr_package>, reg_recode X<reg_recode>, reg_scan_name
+X<reg_scan_name>, reg_skipcomment X<reg_skipcomment>, reg_temp_copy
+X<reg_temp_copy>, reganode X<reganode>, regatom X<regatom>, regbranch
+X<regbranch>, regclass X<regclass>, regcppop X<regcppop>, regcppush
+X<regcppush>, regcurly X<regcurly>, regdump_extflags X<regdump_extflags>,
+reghop3 X<reghop3>, reghop4 X<reghop4>, reghopmaybe3 X<reghopmaybe3>,
+reginclass X<reginclass>, reginsert X<reginsert>, regmatch X<regmatch>,
+regpiece X<regpiece>, regpposixcc X<regpposixcc>, regprop X<regprop>,
+regrepeat X<regrepeat>, regtail X<regtail>, regtail_study X<regtail_study>,
+regtry X<regtry>, reguni X<reguni>, regwhite X<regwhite>, report_evil_fh
+X<report_evil_fh>, require_tie_mod X<require_tie_mod>, restore_magic
+X<restore_magic>, rsignal_restore X<rsignal_restore>, rsignal_save
+X<rsignal_save>, run_body X<run_body>, run_user_filter X<run_user_filter>,
+rxres_free X<rxres_free>, rxres_restore X<rxres_restore>, rxres_save
+X<rxres_save>, same_dirent X<same_dirent>, save_freeop X<save_freeop>,
+save_hek_flags X<save_hek_flags>, save_hints X<save_hints>, save_lines
+X<save_lines>, save_magic X<save_magic>, save_op X<save_op>,
+save_pushi32ptr X<save_pushi32ptr>, save_pushptri32ptr
+X<save_pushptri32ptr>, save_pushptrptr X<save_pushptrptr>, save_scalar_at
+X<save_scalar_at>, sawparens X<sawparens>, scalar X<scalar>,
+scalar_mod_type X<scalar_mod_type>, scalarboolean X<scalarboolean>,
+scalarkids X<scalarkids>, scalarseq X<scalarseq>, scalarvoid X<scalarvoid>,
+scan_commit X<scan_commit>, scan_const X<scan_const>, scan_formline
+X<scan_formline>, scan_heredoc X<scan_heredoc>, scan_ident X<scan_ident>,
+scan_inputsymbol X<scan_inputsymbol>, scan_pat X<scan_pat>, scan_str
+X<scan_str>, scan_subst X<scan_subst>, scan_trans X<scan_trans>, scan_word
+X<scan_word>, scope X<scope>, search_const X<search_const>, sequence
+X<sequence>, sequence_num X<sequence_num>, sequence_tail X<sequence_tail>,
+share_hek_flags X<share_hek_flags>, sighandler X<sighandler>, simplify_sort
+X<simplify_sort>, skipspace X<skipspace>, skipspace0 X<skipspace0>,
+skipspace1 X<skipspace1>, skipspace2 X<skipspace2>, softref2xv
+X<softref2xv>, sortcv X<sortcv>, sortcv_stacked X<sortcv_stacked>,
+sortcv_xsub X<sortcv_xsub>, space_join_names_mortal
+X<space_join_names_mortal>, start_force X<start_force>, stdize_locale
+X<stdize_locale>, store_cop_label X<store_cop_label>, strip_return
+X<strip_return>, study_chunk X<study_chunk>, sub_crush_depth
+X<sub_crush_depth>, sublex_done X<sublex_done>, sublex_push X<sublex_push>,
+sublex_start X<sublex_start>, sv_2iuv_common X<sv_2iuv_common>,
+sv_2iuv_non_preserve X<sv_2iuv_non_preserve>, sv_add_backref
+X<sv_add_backref>, sv_catxmlpvn X<sv_catxmlpvn>, sv_catxmlsv
+X<sv_catxmlsv>, sv_del_backref X<sv_del_backref>, sv_dup_inc_multiple
+X<sv_dup_inc_multiple>, sv_exp_grow X<sv_exp_grow>, sv_free2 X<sv_free2>,
+sv_i_ncmp X<sv_i_ncmp>, sv_kill_backrefs X<sv_kill_backrefs>, sv_ncmp
+X<sv_ncmp>, sv_pos_b2u_midway X<sv_pos_b2u_midway>, sv_pos_u2b_cached
+X<sv_pos_u2b_cached>, sv_pos_u2b_forwards X<sv_pos_u2b_forwards>,
+sv_pos_u2b_midway X<sv_pos_u2b_midway>, sv_release_COW X<sv_release_COW>,
+sv_setsv_cow X<sv_setsv_cow>, sv_unglob X<sv_unglob>, sv_xmlpeek
+X<sv_xmlpeek>, swallow_bom X<swallow_bom>, swash_get X<swash_get>,
+to_byte_substr X<to_byte_substr>, to_utf8_substr X<to_utf8_substr>,
+token_free X<token_free>, token_getmad X<token_getmad>, tokenize_use
+X<tokenize_use>, tokeq X<tokeq>, tokereport X<tokereport>,
+too_few_arguments X<too_few_arguments>, too_many_arguments
+X<too_many_arguments>, uiv_2buf X<uiv_2buf>, unpack_rec X<unpack_rec>,
+unshare_hek X<unshare_hek>, unshare_hek_or_pvn X<unshare_hek_or_pvn>,
+unwind_handler_stack X<unwind_handler_stack>, update_debugger_info
+X<update_debugger_info>, usage X<usage>, utf16_textfilter
+X<utf16_textfilter>, utf8_mg_pos_cache_update X<utf8_mg_pos_cache_update>,
+utilize X<utilize>, validate_suid X<validate_suid>, varname X<varname>,
+vdie X<vdie>, vdie_common X<vdie_common>, vdie_croak_common
+X<vdie_croak_common>, visit X<visit>, vivify_defelem X<vivify_defelem>,
+vivify_ref X<vivify_ref>, wait4pid X<wait4pid>, watch X<watch>,
+write_no_mem X<write_no_mem>, write_to_stderr X<write_to_stderr>,
+xmldump_all X<xmldump_all>, xmldump_all_perl X<xmldump_all_perl>,
+xmldump_attr X<xmldump_attr>, xmldump_eval X<xmldump_eval>, xmldump_form
+X<xmldump_form>, xmldump_indent X<xmldump_indent>, xmldump_packsubs
+X<xmldump_packsubs>, xmldump_packsubs_perl X<xmldump_packsubs_perl>,
+xmldump_sub X<xmldump_sub>, xmldump_sub_perl X<xmldump_sub_perl>,
+xmldump_vindent X<xmldump_vindent>, yyerror X<yyerror>, yylex X<yylex>,
+yyparse X<yyparse>, yywarn X<yywarn>
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 perliol - C API for Perl's implementation of IO in Layers.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item History and Background
+
+=item Basic Structure
+
+=item Layers vs Disciplines
+
+=item Data Structures
+
+=item Functions and Attributes
+
+=item Per-instance Data
+
+=item Layers in action.
+
+=item Per-instance flag bits
+
+PERLIO_F_EOF, PERLIO_F_CANWRITE, PERLIO_F_CANREAD, PERLIO_F_ERROR,
+PERLIO_F_TRUNCATE, PERLIO_F_APPEND, PERLIO_F_CRLF, PERLIO_F_UTF8,
+PERLIO_F_UNBUF, PERLIO_F_WRBUF, PERLIO_F_RDBUF, PERLIO_F_LINEBUF,
+PERLIO_F_TEMP, PERLIO_F_OPEN, PERLIO_F_FASTGETS
+
+=item Methods in Detail
+
+fsize, name, size, kind, PERLIO_K_BUFFERED, PERLIO_K_RAW, PERLIO_K_CANCRLF,
+PERLIO_K_FASTGETS, PERLIO_K_MULTIARG, Pushed, Popped, Open, Binmode,
+Getarg, Fileno, Dup, Read, Write, Seek, Tell, Close, Flush, Fill, Eof,
+Error, Clearerr, Setlinebuf, Get_base, Get_bufsiz, Get_ptr, Get_cnt,
+Set_ptrcnt
+
+=item Utilities
+
+=item Implementing PerlIO Layers
+
+C implementations, Perl implementations
+
+=item Core Layers
+
+"unix", "perlio", "stdio", "crlf", "mmap", "pending", "raw", "utf8"
+
+=item Extension Layers
+
+":encoding", ":scalar", ":via"
+
+=back
+
+=item TODO
+
+=back
+
+=head2 perlapio - perl's IO abstraction interface.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+1. USE_STDIO, 2. USE_SFIO, 3. USE_PERLIO, B<PerlIO_stdin()>,
+B<PerlIO_stdout()>, B<PerlIO_stderr()>, B<PerlIO_open(path, mode)>,
+B<PerlIO_fdopen(fd,mode)>, B<PerlIO_reopen(path,mode,f)>,
+B<PerlIO_printf(f,fmt,...)>, B<PerlIO_vprintf(f,fmt,a)>,
+B<PerlIO_stdoutf(fmt,...)>, B<PerlIO_read(f,buf,count)>,
+B<PerlIO_write(f,buf,count)>, B<PerlIO_close(f)>, B<PerlIO_puts(f,s)>,
+B<PerlIO_putc(f,c)>, B<PerlIO_ungetc(f,c)>, B<PerlIO_getc(f)>,
+B<PerlIO_eof(f)>, B<PerlIO_error(f)>, B<PerlIO_fileno(f)>,
+B<PerlIO_clearerr(f)>, B<PerlIO_flush(f)>, B<PerlIO_seek(f,offset,whence)>,
+B<PerlIO_tell(f)>, B<PerlIO_getpos(f,p)>, B<PerlIO_setpos(f,p)>,
+B<PerlIO_rewind(f)>, B<PerlIO_tmpfile()>, B<PerlIO_setlinebuf(f)>
+
+=over 4
+
+=item Co-existence with stdio
+
+B<PerlIO_importFILE(f,mode)>, B<PerlIO_exportFILE(f,mode)>,
+B<PerlIO_releaseFILE(p,f)>, B<PerlIO_findFILE(f)>
+
+=item "Fast gets" Functions
+
+B<PerlIO_fast_gets(f)>, B<PerlIO_has_cntptr(f)>, B<PerlIO_get_cnt(f)>,
+B<PerlIO_get_ptr(f)>, B<PerlIO_set_ptrcnt(f,p,c)>, B<PerlIO_canset_cnt(f)>,
+B<PerlIO_set_cnt(f,c)>, B<PerlIO_has_base(f)>, B<PerlIO_get_base(f)>,
+B<PerlIO_get_bufsiz(f)>
+
+=item Other Functions
+
+PerlIO_apply_layers(f,mode,layers), PerlIO_binmode(f,ptype,imode,layers),
+'E<lt>' read, 'E<gt>' write, '+' read/write, PerlIO_debug(fmt,...)
+
+=back
+
+=back
+
+=head2 perlhack - How to hack at the Perl internals
+
+=over 4
+
+=item DESCRIPTION
+
+Does concept match the general goals of Perl?, Where is the
+implementation?, Backwards compatibility, Could it be a module instead?, Is
+the feature generic enough?, Does it potentially introduce new bugs?, Does
+it preclude other desirable features?, Is the implementation robust?, Is
+the implementation generic enough to be portable?, Is the implementation
+tested?, Is there enough documentation?, Is there another way to do it?,
+Does it create too much work?, Patches speak louder than words
+
+=over 4
+
+=item Keeping in sync
+
+=item Perlbug administration
+
+=item Submitting patches
+
+L<perlguts>, L<perlxstut> and L<perlxs>, L<perlapi>,
+F<Porting/pumpkin.pod>, The perl5-porters FAQ
+
+=item Finding Your Way Around
+
+Core modules, Tests, Documentation, Configure, Interpreter
+
+=item Elements of the interpreter
+
+Startup, Parsing, Optimization, Running, Exception handing
+
+=item Internal Variable Types
+
+=item Op Trees
+
+=item Stacks
+
+Argument stack, Mark stack, Save stack
+
+=item Millions of Macros
+
+=item The .i Targets
+
+=back
+
+=item SOURCE CODE STATIC ANALYSIS
+
+=over 4
+
+=item lint, splint
+
+=item Coverity
+
+=item cpd (cut-and-paste detector)
+
+=item gcc warnings
+
+=item Warnings of other C compilers
+
+=item DEBUGGING
+
+=item Poking at Perl
+
+=item Using a source-level debugger
+
+run [args], break function_name, break source.c:xxx, step, next, continue,
+finish, 'enter', print
+
+=item gdb macro support
+
+=item Dumping Perl Data Structures
+
+=item Patching
+
+=item Patching a core module
+
+=item Adding a new function to the core
+
+=item Writing a test
+
+F<t/base/>, F<t/cmd/>, F<t/comp/>, F<t/io/>, F<t/lib/>, F<t/mro/>,
+F<t/op/>, F<t/re/>, F<t/run/>, F<t/uni/>, F<t/win32/>, F<t/x2p>, t/base
+t/comp, t/cmd t/run t/io t/op, t/lib ext lib
+
+=item Special Make Test Targets
+
+coretest, test.deparse, test.taintwarn, minitest, test.valgrind
+check.valgrind utest.valgrind ucheck.valgrind, test.third check.third
+utest.third ucheck.third, test.torture torturetest, utest ucheck test.utf8
+check.utf8, minitest.utf16 test.utf16, test_harness, Parallel tests
+
+=item Running tests by hand
+
+-v, -torture, -re=PATTERN, -re LIST OF PATTERNS, PERL_CORE=1,
+PERL_DESTRUCT_LEVEL=2, PERL, PERL_SKIP_TTY_TEST, PERL_TEST_Net_Ping,
+PERL_TEST_NOVREXX, PERL_TEST_NUMCONVERTS
+
+=item Common problems when patching Perl source code
+
+=item Perl environment problems
+
+=item Portability problems
+
+=item Problematic System Interfaces
+
+=item Security problems
+
+=back
+
+=item EXTERNAL TOOLS FOR DEBUGGING PERL
+
+=over 4
+
+=item Rational Software's Purify
+
+=item Purify on Unix
+
+-Accflags=-DPURIFY, -Doptimize='-g', -Uusemymalloc, -Dusemultiplicity
+
+=item Purify on NT
+
+DEFINES, USE_MULTI = define, #PERL_MALLOC = define, CFG = Debug
+
+=item valgrind
+
+=item Compaq's/Digital's/HP's Third Degree
+
+=item PERL_DESTRUCT_LEVEL
+
+=item PERL_MEM_LOG
+
+=item Profiling
+
+=item Gprof Profiling
+
+-a, -b, -e routine, -f routine, -s, -z
+
+=item GCC gcov Profiling
+
+=item Pixie Profiling
+
+-h, -l, -p[rocedures], -h[eavy], -i[nvocations], -l[ines], -testcoverage,
+-z[ero]
+
+=item Miscellaneous tricks
+
+=back
+
+=item CONCLUSION
+
+I<The Road goes ever on and on, down from the door where it began.>
+
+=over 4
+
+=item Metaphoric Quotations
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlpolicy - Various and sundry policies and commitments related to
+the perl core
+
+=over 4
+
+=item DESCRIPTION
+
+=item MAINTENANCE AND SUPPORT
+
+=item BACKWARD COMPATIBILITY AND DEPRECATION
+
+=over 4
+
+=item Terminology
+
+experimental, deprecated, discouraged, removed
+
+=back
+
+=item MAINTENANCE BRANCHES
+
+=over 4
+
+=item Getting changes into a maint branch
+
+=back
+
+=item CONTRIBUTED MODULES
+
+=over 4
+
+=item A Social Contract about Artistic Control
+
+=back
+
+=item CREDITS
+
+=back
+
+=head2 perlrepository - Using the Perl source repository
+
+=over 4
+
+=item SYNOPSIS
+
+=item Getting access to the repository
+
+=over 4
+
+=item Read access via the web
+
+=item Read access via Git
+
+=item Write access to the repository
+
+=item A note on camel and dromedary
+
+=back
+
+=item Overview of the repository
+
+=over 4
+
+=item Finding out your status
+
+=back
+
+=item Submitting a patch
+
+=over 4
+
+=item Using git to send patch emails
+
+=item A note on derived files
+
+=item Getting your patch accepted
+
+Commit message, What, Why, How, Comments, Comments, Comments, Style,
+Testsuite
+
+=back
+
+=item Accepting a patch
+
+=item Cleaning a working directory
+
+=item Bisecting
+
+=item Submitting a patch via GitHub
+
+=item Merging from a branch via GitHub
+
+=item Topic branches and rewriting history
+
+=item Committing to maintenance versions
+
+=item Grafts
+
+=item SEE ALSO
+
+=back
+
+=head2 perlbook - Perl book information
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 perlcommunity - a brief overview of the Perl community
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Where to find the community
+
+=item Mailing lists and Newsgroups
+
+=item IRC
+
+=item Websites
+
+L<http://perl.com/>, L<http://use.perl.org/>, L<http://www.perlmonks.org/>
+
+=item User Groups
+
+=item Workshops
+
+=item Hackathons
+
+=item Conventions
+
+=item Calendar of Perl Events
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perltodo - Perl TO-DO List
+
+=over 4
+
+=item DESCRIPTION
+
+=item Tasks that only need Perl knowledge
+
+=over 4
+
+=item Improve Porting/cmpVERSION.pl to work from git tags
+
+=item Migrate t/ from custom TAP generation
+
+=item Test that regen.pl was run
+
+=item Automate perldelta generation
+
+Modules and Pragmata, New Documentation, New Tests
+
+=item Remove duplication of test setup.
+
+=item POD -E<gt> HTML conversion in the core still sucks
+
+=item Make ExtUtils::ParseXS use strict;
+
+=item Make Schwern poorer
+
+=item Improve the coverage of the core tests
+
+=item test B
+
+=item A decent benchmark
+
+=item fix tainting bugs
+
+=item Dual life everything
+
+=item Move dual-life pod/*.PL into ext
+
+=item POSIX memory footprint
+
+=item embed.pl/makedef.pl
+
+=item use strict; and AutoLoad
+
+=item profile installman
+
+=item enable lexical enabling/disabling of inidvidual warnings
+
+=back
+
+=item Tasks that need a little sysadmin-type knowledge
+
+=over 4
+
+=item make HTML install work
+
+=item compressed man pages
+
+=item Add a code coverage target to the Makefile
+
+=item Make Config.pm cope with differences between built and installed perl
+
+=item linker specification files
+
+=item Cross-compile support
+
+=item roffitall
+
+=item Split "linker" from "compiler"
+
+C<cc> (in F<cc.U>), C<ld> (in F<dlsrc.U>)
+
+=item Configure Windows using PowerShell
+
+=item decouple -g and -DDEBUGGING
+
+=back
+
+=item Tasks that need a little C knowledge
+
+=over 4
+
+=item Weed out needless PERL_UNUSED_ARG
+
+=item Modernize the order of directories in @INC
+
+=item -Duse32bit*
+
+=item Profile Perl - am I hot or not?
+
+=item Allocate OPs from arenas
+
+=item Improve win32/wince.c
+
+=item Use secure CRT functions when building with VC8 on Win32
+
+=item Fix POSIX::access() and chdir() on Win32
+
+=item strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf()
+
+=item -D_FORTIFY_SOURCE=2, -fstack-protector
+
+=item Arenas for GPs? For MAGIC?
+
+=item Shared arenas
+
+=back
+
+=item Tasks that need a knowledge of XS
+
+=over 4
+
+=item Write an XS cookbook
+
+=item Allow XSUBs to inline themselves as OPs
+
+=item Remove the use of SVs as temporaries in dump.c
+
+=item safely supporting POSIX SA_SIGINFO
+
+=item autovivification
+
+=item Unicode in Filenames
+
+=item Unicode in %ENV
+
+=item Unicode and glob()
+
+=item use less 'memory'
+
+=item Re-implement C<:unique> in a way that is actually thread-safe
+
+=item Make tainting consistent
+
+=item readpipe(LIST)
+
+=item Audit the code for destruction ordering assumptions
+
+=item Extend PerlIO and PerlIO::Scalar
+
+=item -C on the #! line
+
+=item Organize error messages
+
+=back
+
+=item Tasks that need a knowledge of the interpreter
+
+=over 4
+
+=item forbid labels with keyword names
+
+=item truncate() prototype
+
+=item decapsulation of smart match argument
+
+=item error reporting of [$a ; $b]
+
+=item lexicals used only once
+
+=item UTF-8 revamp
+
+=item Properly Unicode safe tokeniser and pads.
+
+=item state variable initialization in list context
+
+=item Implement $value ~~ 0 .. $range
+
+=item A does() built-in
+
+=item Tied filehandles and write() don't mix
+
+=item Propagate compilation hints to the debugger
+
+=item Attach/detach debugger from running program
+
+=item LVALUE functions for lists
+
+=item regexp optimiser optional
+
+=item C</w> regex modifier
+
+=item optional optimizer
+
+=item You WANT *how* many
+
+=item lexical aliases
+
+=item entersub XS vs Perl
+
+=item Self-ties
+
+=item Optimize away @_
+
+=item Virtualize operating system access
+
+=item Investigate PADTMP hash pessimisation
+
+=item Store the current pad in the OP slab allocator
+
+=item repack the optree
+
+=item eliminate incorrect line numbers in warnings
+
+=item optimize tail-calls
+
+=back
+
+=item Big projects
+
+=over 4
+
+=item make ithreads more robust
+
+=item iCOW
+
+=item (?{...}) closures in regexps
+
+=item A re-entrant regexp engine
+
+=item Add class set operations to regexp engine
+
+=back
+
+=item Tasks for microperl
+
+=over 4
+
+=item make creating uconfig.sh automatic
+
+=item make creating Makefile.micro automatic
+
+=item do away with fork/exec/wait?
+
+=item some of the uconfig.sh really needs to be probed (using cc) in
+buildtime:
+
+=back
+
+=back
+
+=head2 perldoc - Look up Perl documentation in Pod format.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+B<-h>, B<-D>, B<-t>, B<-u>, B<-m> I<module>, B<-l>, B<-F>, B<-f>
+I<perlfunc>, B<-q> I<perlfaq-search-regexp>, B<-v> I<perlvar>, B<-T>, B<-d>
+I<destination-filename>, B<-o> I<output-formatname>, B<-M> I<module-name>,
+B<-w> I<option:value> or B<-w> I<option>, B<-X>, B<-L> I<language_code>,
+B<PageName|ModuleName|ProgramName>, B<-n> I<some-formatter>, B<-r>, B<-i>,
+B<-V>
+
+=item SECURITY
+
+=item ENVIRONMENT
+
+=item CHANGES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 perlhist - the Perl history records
+
+=over 4
+
+=item DESCRIPTION
+
+=item INTRODUCTION
+
+=item THE KEEPERS OF THE PUMPKIN
+
+=over 4
+
+=item PUMPKIN?
+
+=back
+
+=item THE RECORDS
+
+=over 4
+
+=item SELECTED RELEASE SIZES
+
+=item SELECTED PATCH SIZES
+
+=back
+
+=item THE KEEPERS OF THE RECORDS
+
+=back
+
+=head2 perldelta - what is new for perl v5.12.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item C<keys>, C<values> work on arrays
+
+=back
+
+=item Bug Fixes
+
+=item Platform Specific Notes
+
+Solaris, VMS, VOS
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5123delta, perldelta - what is new for perl v5.12.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item C<keys>, C<values> work on arrays
+
+=back
+
+=item Bug Fixes
+
+=item Platform Specific Notes
+
+Solaris, VMS, VOS
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5122delta - what is new for perl v5.12.2
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Pragmata
+
+=item Pragmata Changes
+
+=item Updated Modules
+
+C<Carp>, C<CPANPLUS>, C<File::Glob>, C<File::Copy>, C<File::Spec>
+
+=back
+
+=item Utility Changes
+
+=item Changes to Existing Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Configuration improvements
+
+=item Compilation improvements
+
+=back
+
+=item Selected Bug Fixes
+
+=item Platform Specific Notes
+
+=over 4
+
+=item AIX
+
+=item Windows
+
+=item VMS
+
+=back
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5121delta, perldelta - what is new for perl v5.12.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Pragmata Changes
+
+=item Updated Modules
+
+=back
+
+=item Changes to Existing Documentation
+
+=item Testing
+
+=over 4
+
+=item Testing Improvements
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Configuration improvements
+
+=back
+
+=item Bug Fixes
+
+=item Platform Specific Notes
+
+=over 4
+
+=item HP-UX
+
+=item AIX
+
+=item FreeBSD 7
+
+=item VMS
+
+=back
+
+=item Known Problems
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5120delta - what is new for perl v5.12.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Core Enhancements
+
+=over 4
+
+=item New C<package NAME VERSION> syntax
+
+=item The C<...> operator
+
+=item Implicit strictures
+
+=item Unicode improvements
+
+=item Y2038 compliance
+
+=item qr overloading
+
+=item Pluggable keywords
+
+=item APIs for more internals
+
+=item Overridable function lookup
+
+=item A proper interface for pluggable Method Resolution Orders
+
+=item C<\N> experimental regex escape
+
+=item DTrace support
+
+=item Support for C<configure_requires> in CPAN module metadata
+
+=item C<each> is now more flexible
+
+=item C<when> as a statement modifier
+
+=item C<$,> flexibility
+
+=item // in when clauses
+
+=item Enabling warnings from your shell environment
+
+=item C<delete local>
+
+=item New support for Abstract namespace sockets
+
+=item 32-bit limit on substr arguments removed
+
+=back
+
+=item Potentially Incompatible Changes
+
+=over 4
+
+=item Deprecations warn by default
+
+=item Version number formats
+
+=item @INC reorganization
+
+=item REGEXPs are now first class
+
+=item Switch statement changes
+
+flip-flop operators, defined-or operator
+
+=item Smart match changes
+
+=item Other potentially incompatible changes
+
+=back
+
+=item Deprecations
+
+suidperl, Use of C<:=> to mean an empty attribute list, C<<
+UNIVERSAL->import() >>, Use of "goto" to jump into a construct, Custom
+character names in \N{name} that don't look like names, Deprecated Modules,
+L<Class::ISA>, L<Pod::Plainer>, L<Shell>, L<Switch>, Assignment to $[, Use
+of the attribute :locked on subroutines, Use of "locked" with the
+attributes pragma, Use of "unique" with the attributes pragma, Perl_pmflag,
+Numerous Perl 4-era libraries
+
+=item Unicode overhaul
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Pragmata
+
+C<autodie>, C<Compress::Raw::Bzip2>, C<overloading>, C<parent>,
+C<Parse::CPAN::Meta>, C<VMS::DCLsym>, C<VMS::Stdio>,
+C<XS::APItest::KeywordRPN>
+
+=item Updated Pragmata
+
+C<base>, C<bignum>, C<charnames>, C<constant>, C<diagnostics>, C<feature>,
+C<less>, C<lib>, C<mro>, C<overload>, C<threads>, C<threads::shared>,
+C<version>, C<warnings>
+
+=item Updated Modules
+
+C<Archive::Extract>, C<Archive::Tar>, C<Attribute::Handlers>,
+C<AutoLoader>, C<B::Concise>, C<B::Debug>, C<B::Deparse>, C<B::Lint>,
+C<CGI>, C<Class::ISA>, C<Compress::Raw::Zlib>, C<CPAN>, C<CPANPLUS>,
+C<CPANPLUS::Dist::Build>, C<Data::Dumper>, C<DB_File>, C<Devel::PPPort>,
+C<Digest>, C<Digest::MD5>, C<Digest::SHA>, C<Encode>, C<Exporter>,
+C<ExtUtils::CBuilder>, C<ExtUtils::Command>, C<ExtUtils::Constant>,
+C<ExtUtils::Install>, C<ExtUtils::MakeMaker>, C<ExtUtils::Manifest>,
+C<ExtUtils::ParseXS>, C<File::Fetch>, C<File::Path>, C<File::Temp>,
+C<Filter::Simple>, C<Filter::Util::Call>, C<Getopt::Long>, C<IO>,
+C<IO::Zlib>, C<IPC::Cmd>, C<IPC::SysV>, C<Locale::Maketext>,
+C<Locale::Maketext::Simple>, C<Log::Message>, C<Log::Message::Simple>,
+C<Math::BigInt>, C<Math::BigInt::FastCalc>, C<Math::BigRat>,
+C<Math::Complex>, C<Memoize>, C<MIME::Base64>, C<Module::Build>,
+C<Module::CoreList>, C<Module::Load>, C<Module::Load::Conditional>,
+C<Module::Loaded>, C<Module::Pluggable>, C<Net::Ping>, C<NEXT>,
+C<Object::Accessor>, C<Package::Constants>, C<PerlIO>, C<Pod::Parser>,
+C<Pod::Perldoc>, C<Pod::Plainer>, C<Pod::Simple>, C<Safe>, C<SelfLoader>,
+C<Storable>, C<Switch>, C<Sys::Syslog>, C<Term::ANSIColor>, C<Term::UI>,
+C<Test>, C<Test::Harness>, C<Test::Simple>, C<Text::Balanced>,
+C<Text::ParseWords>, C<Text::Soundex>, C<Thread::Queue>,
+C<Thread::Semaphore>, C<Tie::RefHash>, C<Time::HiRes>, C<Time::Local>,
+C<Time::Piece>, C<Unicode::Collate>, C<Unicode::Normalize>, C<Win32>,
+C<Win32API::File>, C<XSLoader>
+
+=item Removed Modules and Pragmata
+
+C<attrs>, C<CPAN::API::HOWTO>, C<CPAN::DeferedCode>, C<CPANPLUS::inc>,
+C<DCLsym>, C<ExtUtils::MakeMaker::bytes>, C<ExtUtils::MakeMaker::vmsish>,
+C<Stdio>, C<Test::Harness::Assert>, C<Test::Harness::Iterator>,
+C<Test::Harness::Point>, C<Test::Harness::Results>,
+C<Test::Harness::Straps>, C<Test::Harness::Util>, C<XSSymSet>
+
+=item Deprecated Modules and Pragmata
+
+=back
+
+=item Documentation
+
+=over 4
+
+=item New Documentation
+
+=item Changes to Existing Documentation
+
+=back
+
+=item Selected Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=item Internal Changes
+
+=item Testing
+
+=over 4
+
+=item Testing improvements
+
+Parallel tests, Test harness flexibility, Test watchdog
+
+=item New Tests
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item New Diagnostics
+
+=item Changed Diagnostics
+
+C<Illegal character in prototype for %s : %s>, C<Prototype after '%c' for
+%s : %s>
+
+=back
+
+=item Utility Changes
+
+=item Selected Bug Fixes
+
+=item Platform Specific Changes
+
+=over 4
+
+=item New Platforms
+
+Haiku, MirOS BSD
+
+=item Discontinued Platforms
+
+Domain/OS, MiNT, Tenon MachTen
+
+=item Updated Platforms
+
+AIX, Cygwin, Darwin (Mac OS X), DragonFly BSD, FreeBSD, Irix, NetBSD,
+OpenVMS, Stratus VOS, Symbian, Windows
+
+=back
+
+=item Known Problems
+
+=item Errata
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5115delta - what is new for perl v5.11.5
+
+=over 4
+
+=item DESCRIPTION
+
+=item Core Enhancements
+
+=over 4
+
+=item 32-bit limit on substr arguments removed
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Pragmata Changes
+
+C<version>
+
+=item Updated Modules
+
+C<B::Debug>, C<CPAN>, C<CPANPLUS::Dist::Build>, C<Pod::Perldoc>,
+C<Pod::Plainer>, C<Safe>, C<Socket>, C<podlators>
+
+=back
+
+=item Changes to Existing Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Configuration improvements
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item New Tests
+
+F<t/op/filehandle.t>, F<t/op/time_loop.t>
+
+=item Known Problems
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5114delta - what is new for perl v5.11.4
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Version number formats
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode properties
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Pragmata Changes
+
+C<less>, C<version>, C<warnings>
+
+=item Updated Modules
+
+C<Archive::Extract>, C<B::Deparse>, C<Compress::Raw::Bzip2>,
+C<Compress::Raw::Zlib>, C<CPAN>, C<File::Fetch>, C<Module::Build>, C<Safe>
+
+=item Removed Modules and Pragmata
+
+C<Devel::DProf::V>
+
+=back
+
+=item Changes to Existing Documentation
+
+=over 4
+
+=item Configuration improvements
+
+=item Platform Specific Changes
+
+VMS
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+New warning category C<illegalproto>, lvalue attribute ignored after the
+subroutine has been defined
+
+=item Changed Internals
+
+=item Known Problems
+
+=item Deprecations
+
+C<< UNIVERSAL-E<gt>import() >>
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5113delta - what is new for perl v5.11.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Filehandles are blessed directly into C<IO::Handle>, as C<FileHandle>
+is merely a wrapper around C<IO::Handle>.
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode version
+
+=item Unicode properties
+
+=item Regular Expressions
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Pragmata Changes
+
+C<constant>, C<diagnostics>, C<feature>, C<legacy>, C<threads>, C<warnings>
+
+=item Updated Modules
+
+C<Archive::Extract>, C<CPAN>, C<CPANPLUS>, C<Encode>,
+C<ExtUtils::MakeMaker>, C<File::Path>, C<Module::Build>,
+C<Module::CoreList>, C<POSIX>, C<Pod::Simple>, C<Safe>
+
+=back
+
+=item Utility Changes
+
+F<perlbug>
+
+=item Changes to Existing Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Testing improvements
+
+It's now possible to override C<PERL5OPT> and friends in F<t/TEST>
+
+=item Platform Specific Changes
+
+Win32, cygwin, Enable IPv6 support on cygwin 1.7 and newer, OpenVMS, Make
+-UDEBUGGING the default on VMS for 5.12.0
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item New Tests
+
+t/comp/final_line_num.t, t/comp/form_scope.t, t/comp/line_debug.t,
+t/op/filetest_t.t, t/op/qr.t, t/op/utf8cache.t, t/re/uniprops.t
+
+=item Deprecations
+
+Use of "goto" to jump into a construct is deprecated
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5112delta - what is new for perl v5.11.2
+
+=over 4
+
+=item DESCRIPTION
+
+=item Core Enhancements
+
+=over 4
+
+=item qr overloading
+
+=item Pluggable keywords
+
+=item APIs for more internals
+
+=item Overridable function lookup
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Pragmata
+
+C<legacy>
+
+=item Pragmata Changes
+
+C<diagnostics>, C<overload>
+
+=item Updated Modules
+
+C<B::Concise>, C<B::Deparse>, C<Carp>, C<Compress::Zlib>, C<CPANPLUS>,
+C<Encode>, C<ExtUtils::CBuilder>, C<Env>, C<File::Fetch>, C<I8N::Langinfo>,
+C<I8N::LangTags>, C<IO::Compress>, C<IPC::Cmd>, C<List::Util>,
+C<Locale::Maketext>, C<Module::Build>, C<Module::CoreList>, C<Pod::Simple>,
+C<Scalar::Util>, C<Switch>
+
+=back
+
+=item Utility Changes
+
+F<a2p>
+
+=item Performance Enhancements
+
+=item New or Changed Diagnostics
+
+C<Bad plugin affecting keyword '%s'>, C<gmtime(%.0f) too large>, C<Lexing
+code attempted to stuff non-Latin-1 character into Latin-1 input>, C<Lexing
+code internal error (%s)>, C<localtime(%.0f) too large>, C<Overloaded
+dereference did not return a reference>, C<Overloaded qr did not return a
+REGEXP>, C<Perl_pmflag() is deprecated, and will be removed from the XS
+API>, C<Runaway format>
+
+=item Changed Internals
+
+=item New Tests
+
+F<t/op/while_readdir.t>
+
+=item Known Problems
+
+Known test failures on VMS
+
+=item Deprecations
+
+=over 4
+
+=item Use of C<:=> to mean an empty attribute list is now deprecated.
+
+=back
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5111delta - what is new for perl v5.11.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item Add C<package NAME VERSION> syntax
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Updated Modules
+
+=back
+
+=item New Documentation
+
+=item Changes to Existing Documentation
+
+Documentation for C<$1> in perlvar.pod clarified
+
+=item Performance Enhancements
+
+C<if (%foo)> has been optimized to be faster than C<if (keys %foo)>
+
+=item Platform Specific Notes
+
+Darwin (Mac OS X), DragonFly BSD, Win32
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Testing
+
+=item Known Problems
+
+Untriaged test crashes on Windows 2000, Known test failures on VMS
+
+=item Errata for 5.11.0
+
+The Perl 5.11.0 release notes incorrectly described 'delete local'
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5110delta - what is new for perl v5.11.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Unicode interpretation of \w, \d, \s, and the POSIX character classes
+redefined.
+
+=item @INC reorganization
+
+=item Switch statement changes
+
+flip-flop operators, defined-or operator
+
+=item Smart match changes
+
+=item Labels can't be keywords
+
+=item Other incompatible changes
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode Character Database 5.1.0
+
+=item A proper interface for pluggable Method Resolution Orders
+
+=item The C<overloading> pragma
+
+=item C<\N> regex escape
+
+=item Implicit strictures
+
+=item Parallel tests
+
+=item The C<...> operator
+
+=item DTrace support
+
+=item Support for C<configure_requires> in CPAN module metadata
+
+=item C<each> is now more flexible
+
+=item Y2038 compliance
+
+=item C<$,> flexibility
+
+=item // in where clauses
+
+=item Enabling warnings from your shell environment
+
+=item C<delete local>
+
+=item New support for Abstract namespace sockets
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Dual-lifed modules moved
+
+=item New Modules and Pragmata
+
+C<autodie>, C<Compress::Raw::Bzip2>, C<parent>, C<Parse::CPAN::Meta>
+
+=item Pragmata Changes
+
+C<overloading>, C<attrs>, C<charnames>, C<feature>, C<mro>
+
+=item Updated Modules
+
+C<ExtUtils::MakeMaker>, C<Test::Harness>, C<UNIVERSAL>
+
+=back
+
+=item Utility Changes
+
+F<h2ph>, F<h2xs>, F<perl5db.pl>, F<perlbug>, F<perlthanks>
+
+=item New Documentation
+
+L<perlhaiku>, L<perlmroapi>, L<perlperf>, L<perlrepository>
+
+=item Changes to Existing Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item F<ext/> reorganisation
+
+=item Configuration improvements
+
+=item Compilation improvements
+
+=item Platform Specific Changes
+
+AIX, Cygwin, DomainOS, FreeBSD, Irix, Haiku, MachTen, MiNT, MirOS BSD,
+NetBSD, Stratus VOS, Symbian, Win32, VMS
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+C<panic: sv_chop %s>, C<Can't locate package %s for the parents of %s>,
+C<v-string in use/require is non-portable>, C<Deep recursion on subroutine
+"%s">
+
+=item Changed Internals
+
+C<SVf_UTF8>, C<SVs_TEMP>
+
+=item New Tests
+
+t/comp/retainedlines.t, t/io/perlio_fail.t, t/io/perlio_leaks.t,
+t/io/perlio_open.t, t/io/perlio.t, t/io/pvbm.t, t/mro/package_aliases.t,
+t/op/dbm.t, t/op/index_thr.t, t/op/pat_thr.t, t/op/qr_gc.t,
+t/op/reg_email_thr.t, t/op/regexp_qr_embed_thr.t,
+t/op/regexp_unicode_prop.t, t/op/regexp_unicode_prop_thr.t,
+t/op/reg_nc_tie.t, t/op/reg_posixcc.t, t/op/re.t, t/op/setpgrpstack.t,
+t/op/substr_thr.t, t/op/upgrade.t, t/uni/lex_utf8.t, t/uni/tie.t
+
+=item Known Problems
+
+=item Deprecations
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5101delta - what is new for perl v5.10.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Switch statement changes
+
+flip-flop operators, defined-or operator
+
+=item Smart match changes
+
+=item Other incompatible changes
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode Character Database 5.1.0
+
+=item A proper interface for pluggable Method Resolution Orders
+
+=item The C<overloading> pragma
+
+=item Parallel tests
+
+=item DTrace support
+
+=item Support for C<configure_requires> in CPAN module metadata
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Pragmata
+
+C<autodie>, C<Compress::Raw::Bzip2>, C<parent>, C<Parse::CPAN::Meta>
+
+=item Pragmata Changes
+
+C<attributes>, C<attrs>, C<base>, C<bigint>, C<bignum>, C<bigrat>,
+C<charnames>, C<constant>, C<feature>, C<fields>, C<lib>, C<open>,
+C<overload>, C<overloading>, C<version>
+
+=item Updated Modules
+
+C<Archive::Extract>, C<Archive::Tar>, C<Attribute::Handlers>,
+C<AutoLoader>, C<AutoSplit>, C<B>, C<B::Debug>, C<B::Deparse>, C<B::Lint>,
+C<B::Xref>, C<Benchmark>, C<Carp>, C<CGI>, C<Compress::Zlib>, C<CPAN>,
+C<CPANPLUS>, C<CPANPLUS::Dist::Build>, C<Cwd>, C<Data::Dumper>, C<DB>,
+C<DB_File>, C<Devel::PPPort>, C<Digest::MD5>, C<Digest::SHA>, C<DirHandle>,
+C<Dumpvalue>, C<DynaLoader>, C<Encode>, C<Errno>, C<Exporter>,
+C<ExtUtils::CBuilder>, C<ExtUtils::Command>, C<ExtUtils::Constant>,
+C<ExtUtils::Embed>, C<ExtUtils::Install>, C<ExtUtils::MakeMaker>,
+C<ExtUtils::Manifest>, C<ExtUtils::ParseXS>, C<Fatal>, C<File::Basename>,
+C<File::Compare>, C<File::Copy>, C<File::Fetch>, C<File::Find>,
+C<File::Path>, C<File::Spec>, C<File::stat>, C<File::Temp>, C<FileCache>,
+C<FileHandle>, C<Filter::Simple>, C<Filter::Util::Call>, C<FindBin>,
+C<GDBM_File>, C<Getopt::Long>, C<Hash::Util::FieldHash>, C<I18N::Collate>,
+C<IO>, C<IO::Compress::*>, C<IO::Dir>, C<IO::Handle>, C<IO::Socket>,
+C<IO::Zlib>, C<IPC::Cmd>, C<IPC::Open3>, C<IPC::SysV>, C<lib>,
+C<List::Util>, C<Locale::MakeText>, C<Log::Message>, C<Math::BigFloat>,
+C<Math::BigInt>, C<Math::BigInt::FastCalc>, C<Math::BigRat>,
+C<Math::Complex>, C<Math::Trig>, C<Memoize>, C<Module::Build>,
+C<Module::CoreList>, C<Module::Load>, C<Module::Load::Conditional>,
+C<Module::Loaded>, C<Module::Pluggable>, C<NDBM_File>, C<Net::Ping>,
+C<NEXT>, C<Object::Accessor>, C<OS2::REXX>, C<Package::Constants>,
+C<PerlIO>, C<PerlIO::via>, C<Pod::Man>, C<Pod::Parser>, C<Pod::Simple>,
+C<Pod::Text>, C<POSIX>, C<Safe>, C<Scalar::Util>, C<SelectSaver>,
+C<SelfLoader>, C<Socket>, C<Storable>, C<Switch>, C<Symbol>,
+C<Sys::Syslog>, C<Term::ANSIColor>, C<Term::ReadLine>, C<Term::UI>,
+C<Test::Harness>, C<Test::Simple>, C<Text::ParseWords>, C<Text::Tabs>,
+C<Text::Wrap>, C<Thread::Queue>, C<Thread::Semaphore>, C<threads>,
+C<threads::shared>, C<Tie::RefHash>, C<Tie::StdHandle>, C<Time::HiRes>,
+C<Time::Local>, C<Time::Piece>, C<Unicode::Normalize>, C<Unicode::UCD>,
+C<UNIVERSAL>, C<Win32>, C<Win32API::File>, C<XSLoader>
+
+=back
+
+=item Utility Changes
+
+F<h2ph>, F<h2xs>, F<perl5db.pl>, F<perlthanks>
+
+=item New Documentation
+
+L<perlhaiku>, L<perlmroapi>, L<perlperf>, L<perlrepository>, L<perlthanks>
+
+=item Changes to Existing Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item F<ext/> reorganisation
+
+=item Configuration improvements
+
+=item Compilation improvements
+
+=item Platform Specific Changes
+
+AIX, Cygwin, FreeBSD, Irix, Haiku, MirOS BSD, NetBSD, Stratus VOS, Symbian,
+Win32, VMS
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+C<panic: sv_chop %s>, C<Can't locate package %s for the parents of %s>,
+C<v-string in use/require is non-portable>, C<Deep recursion on subroutine
+"%s">
+
+=item Changed Internals
+
+C<SVf_UTF8>, C<SVs_TEMP>
+
+=item New Tests
+
+t/comp/retainedlines.t, t/io/perlio_fail.t, t/io/perlio_leaks.t,
+t/io/perlio_open.t, t/io/perlio.t, t/io/pvbm.t, t/mro/package_aliases.t,
+t/op/dbm.t, t/op/index_thr.t, t/op/pat_thr.t, t/op/qr_gc.t,
+t/op/reg_email_thr.t, t/op/regexp_qr_embed_thr.t,
+t/op/regexp_unicode_prop.t, t/op/regexp_unicode_prop_thr.t,
+t/op/reg_nc_tie.t, t/op/reg_posixcc.t, t/op/re.t, t/op/setpgrpstack.t,
+t/op/substr_thr.t, t/op/upgrade.t, t/uni/lex_utf8.t, t/uni/tie.t
+
+=item Known Problems
+
+=item Deprecations
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl5100delta - what is new for perl 5.10.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Core Enhancements
+
+=over 4
+
+=item The C<feature> pragma
+
+=item New B<-E> command-line switch
+
+=item Defined-or operator
+
+=item Switch and Smart Match operator
+
+=item Regular expressions
+
+Recursive Patterns, Named Capture Buffers, Possessive Quantifiers,
+Backtracking control verbs, Relative backreferences, C<\K> escape, Vertical
+and horizontal whitespace, and linebreak
+
+=item C<say()>
+
+=item Lexical C<$_>
+
+=item The C<_> prototype
+
+=item UNITCHECK blocks
+
+=item New Pragma, C<mro>
+
+=item readdir() may return a "short filename" on Windows
+
+=item readpipe() is now overridable
+
+=item Default argument for readline()
+
+=item state() variables
+
+=item Stacked filetest operators
+
+=item UNIVERSAL::DOES()
+
+=item Formats
+
+=item Byte-order modifiers for pack() and unpack()
+
+=item C<no VERSION>
+
+=item C<chdir>, C<chmod> and C<chown> on filehandles
+
+=item OS groups
+
+=item Recursive sort subs
+
+=item Exceptions in constant folding
+
+=item Source filters in @INC
+
+=item New internal variables
+
+C<${^RE_DEBUG_FLAGS}>, C<${^CHILD_ERROR_NATIVE}>, C<${^RE_TRIE_MAXBUF}>,
+C<${^WIN32_SLOPPY_STAT}>
+
+=item Miscellaneous
+
+=item UCD 5.0.0
+
+=item MAD
+
+=item kill() on Windows
+
+=back
+
+=item Incompatible Changes
+
+=over 4
+
+=item Packing and UTF-8 strings
+
+=item Byte/character count feature in unpack()
+
+=item The C<$*> and C<$#> variables have been removed
+
+=item substr() lvalues are no longer fixed-length
+
+=item Parsing of C<-f _>
+
+=item C<:unique>
+
+=item Effect of pragmas in eval
+
+=item chdir FOO
+
+=item Handling of .pmc files
+
+=item $^V is now a C<version> object instead of a v-string
+
+=item @- and @+ in patterns
+
+=item $AUTOLOAD can now be tainted
+
+=item Tainting and printf
+
+=item undef and signal handlers
+
+=item strictures and dereferencing in defined()
+
+=item C<(?p{})> has been removed
+
+=item Pseudo-hashes have been removed
+
+=item Removal of the bytecode compiler and of perlcc
+
+=item Removal of the JPL
+
+=item Recursive inheritance detected earlier
+
+=item warnings::enabled and warnings::warnif changed to favor users of
+modules
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Upgrading individual core modules
+
+=item Pragmata Changes
+
+C<feature>, C<mro>, Scoping of the C<sort> pragma, Scoping of C<bignum>,
+C<bigint>, C<bigrat>, C<base>, C<strict> and C<warnings>, C<version>,
+C<warnings>, C<less>
+
+=item New modules
+
+=item Selected Changes to Core Modules
+
+C<Attribute::Handlers>, C<B::Lint>, C<B>, C<Thread>
+
+=back
+
+=item Utility Changes
+
+perl -d, ptar, ptardiff, shasum, corelist, h2ph and h2xs, perlivp,
+find2perl, config_data, cpanp, cpan2dist, pod2html
+
+=item New Documentation
+
+=item Performance Enhancements
+
+=over 4
+
+=item In-place sorting
+
+=item Lexical array access
+
+=item XS-assisted SWASHGET
+
+=item Constant subroutines
+
+=item C<PERL_DONT_CREATE_GVSV>
+
+=item Weak references are cheaper
+
+=item sort() enhancements
+
+=item Memory optimisations
+
+=item UTF-8 cache optimisation
+
+=item Sloppy stat on Windows
+
+=item Regular expressions optimisations
+
+Engine de-recursivised, Single char char-classes treated as literals, Trie
+optimisation of literal string alternations, Aho-Corasick start-point
+optimisation
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Configuration improvements
+
+C<-Dusesitecustomize>, Relocatable installations, strlcat() and strlcpy(),
+C<d_pseudofork> and C<d_printf_format_null>, Configure help
+
+=item Compilation improvements
+
+Parallel build, Borland's compilers support, Static build on Windows,
+ppport.h files, C++ compatibility, Support for Microsoft 64-bit compiler,
+Visual C++, Win32 builds
+
+=item Installation improvements
+
+Module auxiliary files
+
+=item New Or Improved Platforms
+
+=back
+
+=item Selected Bug Fixes
+
+strictures in regexp-eval blocks, Calling CORE::require(), Subscripts of
+slices, C<no warnings 'category'> works correctly with -w, threads
+improvements, chr() and negative values, PERL5SHELL and tainting, Using
+*FILE{IO}, Overloading and reblessing, Overloading and UTF-8, eval memory
+leaks fixed, Random device on Windows, PERLIO_DEBUG, PerlIO::scalar and
+read-only scalars, study() and UTF-8, Critical signals, @INC-hook fix,
+C<-t> switch fix, Duping UTF-8 filehandles, Localisation of hash elements
+
+=item New or Changed Diagnostics
+
+Use of uninitialized value, Deprecated use of my() in false conditional,
+!=~ should be !~, Newline in left-justified string, Too late for "-T"
+option, "%s" variable %s masks earlier declaration,
+readdir()/closedir()/etc. attempted on invalid dirhandle, Opening
+dirhandle/filehandle %s also as a file/directory, Use of -P is deprecated,
+v-string in use/require is non-portable, perl -V
+
+=item Changed Internals
+
+=over 4
+
+=item Reordering of SVt_* constants
+
+=item Elimination of SVt_PVBM
+
+=item New type SVt_BIND
+
+=item Removal of CPP symbols
+
+=item Less space is used by ops
+
+=item New parser
+
+=item Use of C<const>
+
+=item Mathoms
+
+=item C<AvFLAGS> has been removed
+
+=item C<av_*> changes
+
+=item $^H and %^H
+
+=item B:: modules inheritance changed
+
+=item Anonymous hash and array constructors
+
+=back
+
+=item Known Problems
+
+=over 4
+
+=item UTF-8 problems
+
+=back
+
+=item Platform Specific Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl595delta - what is new for perl v5.9.5
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Tainting and printf
+
+=item undef and signal handlers
+
+=item strictures and array/hash dereferencing in defined()
+
+=item C<(?p{})> has been removed
+
+=item Pseudo-hashes have been removed
+
+=item Removal of the bytecode compiler and of perlcc
+
+=item Removal of the JPL
+
+=item Recursive inheritance detected earlier
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Regular expressions
+
+Recursive Patterns, Named Capture Buffers, Possessive Quantifiers,
+Backtracking control verbs, Relative backreferences, C<\K> escape, Vertical
+and horizontal whitespace, and linebreak
+
+=item The C<_> prototype
+
+=item UNITCHECK blocks
+
+=item readpipe() is now overridable
+
+=item default argument for readline()
+
+=item UCD 5.0.0
+
+=item Smart match
+
+=item Implicit loading of C<feature>
+
+=back
+
+=item Modules and Pragmas
+
+=over 4
+
+=item New Pragma, C<mro>
+
+=item bignum, bigint, bigrat
+
+=item Math::BigInt/Math::BigFloat
+
+config(), import(), roundmode common, bpi(), bcos(), bsin(), batan(),
+batan2(), bmuladd(), bexp(), bnok(), from_hex(), from_oct(), and
+from_bin(), as_oct()
+
+=item New Core Modules
+
+=item Module changes
+
+C<assertions>, C<base>, C<strict> and C<warnings>, C<warnings>, C<less>,
+C<Attribute::Handlers>, C<B::Lint>, C<B>, C<Thread>
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item C<cpanp>
+
+=item C<cpan2dist>
+
+=item C<pod2html>
+
+=back
+
+=item Documentation
+
+=over 4
+
+=item New manpage, perlunifaq
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item C++ compatibility
+
+=item Visual C++
+
+=item Static build on Win32
+
+=item win32 builds
+
+=item C<d_pseudofork> and C<d_printf_format_null>
+
+=item Help
+
+=item 64bit systems
+
+=item Ports
+
+=back
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item Deprecations
+
+=back
+
+=item Changed Internals
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl594delta - what is new for perl v5.9.4
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item chdir FOO
+
+=item Handling of pmc files
+
+=item @- and @+ in patterns
+
+=item $AUTOLOAD can now be tainted
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item state() variables
+
+=item UNIVERSAL::DOES()
+
+=item Exceptions in constant folding
+
+=item Source filters in @INC
+
+=item MAD
+
+=back
+
+=item Modules and Pragmas
+
+=over 4
+
+=item New Core Modules
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item config_data
+
+=back
+
+=item Documentation
+
+=over 4
+
+=item New manpage, perlpragma
+
+=item New manpage, perlreguts
+
+=item New manpage, perlunitut
+
+=back
+
+=item Performance Enhancements
+
+=over 4
+
+=item Memory optimisations
+
+=item UTF-8 cache optimisation
+
+=item Regular expressions
+
+Engine de-recursivised, Single char char-classes treated as literals, Trie
+optimisation of literal string alternations, Aho-Corasick start-point
+optimisation
+
+=item Sloppy stat on Windows
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Relocatable installations
+
+=item Ports
+
+=item Compilation improvements
+
+=item New probes
+
+=item Windows build improvements
+
+Building XS extensions, Support for 64-bit compiler
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item PERL5SHELL and tainting
+
+=item Using *FILE{IO}
+
+=item Overloading and reblessing
+
+=item Overloading and UTF-8
+
+=item eval memory leaks fixed
+
+=item Random device on Windows
+
+=back
+
+=item New or Changed Diagnostics
+
+State variable %s will be reinitialized
+
+=item Changed Internals
+
+=item Known Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl593delta - what is new for perl v5.9.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Parsing of C<-f _>
+
+=item C<mkdir()>
+
+=item Magic goto and eval
+
+=item C<$#> has been removed
+
+=item C<:unique>
+
+=item Scoping of the C<sort> pragma
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item The C<feature> pragma
+
+=item Switch and Smart Match operator
+
+=item C<say()>
+
+=item C<CLONE_SKIP()>
+
+=item C<${^CHILD_ERROR_NATIVE}>
+
+=item Assertions
+
+=item Unicode Character Database 4.1.0
+
+=item C<no VERSION>
+
+=item Recursive sort subs
+
+=item Effect of pragmas in eval
+
+=item New B<-E> command-line switch
+
+=item C<chdir>, C<chmod> and C<chown> on filehandles
+
+=item OS groups
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Core Modules
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item C<ptar>
+
+=item C<ptardiff>
+
+=item C<shasum>
+
+=item C<h2xs> enhancements
+
+=item C<perlivp> enhancements
+
+=back
+
+=item Documentation
+
+=over 4
+
+=item Perl Glossary
+
+=back
+
+=item Performance Enhancements
+
+=over 4
+
+=item XS-assisted SWASHGET
+
+=item Constant subroutines
+
+=item C<PERL_DONT_CREATE_GVSV>
+
+=item Weak references are cheaper
+
+=item sort() enhancements
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Compilation improvements
+
+=item New Or Improved Platforms
+
+=item New probes
+
+=item Module auxiliary files
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item C<defined $$x>
+
+=item Calling CORE::require()
+
+=item Subscripts of slices
+
+=item Remove over-optimisation
+
+=item sprintf() fixes
+
+=item no warnings 'category' works correctly with -w
+
+=item Smaller fixes
+
+=item More Unicode Fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item Attempt to set length of freed array
+
+=item Non-string passed as bitmask
+
+=item Search pattern not terminated or ternary operator parsed as search
+pattern
+
+=item "%s" variable %s masks earlier declaration
+
+=item readdir()/closedir()/etc. attempted on invalid dirhandle
+
+=back
+
+=item Changed Internals
+
+=over 4
+
+=item B:: modules inheritance changed
+
+=back
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl592delta - what is new for perl v5.9.2
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Packing and UTF-8 strings
+
+=item Miscellaneous
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Malloc wrapping
+
+=item Unicode Character Database 4.0.1
+
+=item suidperl less insecure
+
+=item PERLIO_DEBUG
+
+=item Formats
+
+=item Unicode Character Classes
+
+=item Byte-order modifiers for pack() and unpack()
+
+=item Byte count feature in pack()
+
+=item New variables
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New modules
+
+=item Updated And Improved Modules and Pragmata
+
+B::Concise, Socket, Sys::Syslog, threads
+
+=back
+
+=item Utility Changes
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Known Problems
+
+=item Plans for the next release
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl591delta - what is new for perl v5.9.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item substr() lvalues are no longer fixed-length
+
+=item The C<:unique> attribute is only meaningful for globals
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Lexical C<$_>
+
+=item Tied hashes in scalar context
+
+=item Formats
+
+=item Stacked filetest operators
+
+=back
+
+=item Modules and Pragmata
+
+Benchmark, Carp, Exporter, FindBin, List::Util, threads::shared
+
+=item Utility Changes
+
+=item Documentation
+
+=item Performance Enhancements
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item UTF-8 bugs
+
+=item Threading bugs
+
+=item More bugs
+
+=back
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=over 4
+
+=item Reordering of SVt_* constants
+
+=item Removal of CPP symbols
+
+=item Less space is used by ops
+
+=item New parser
+
+=back
+
+=item Configuration and Building
+
+=item Known Problems
+
+=over 4
+
+=item Platform Specific Problems
+
+=back
+
+=item To-do for perl 5.10.0
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl590delta - what is new for perl v5.9.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Hash Randomisation
+
+=item UTF-8 On Filehandles No Longer Activated By Locale
+
+=item Single-number v-strings are no longer v-strings before "=>"
+
+=item (Win32) The -C Switch Has Been Repurposed
+
+=item (Win32) The /d Switch Of cmd.exe
+
+=item The C<$*> variable has been removed
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Assertions
+
+=item Defined-or operators
+
+=item UTF-8 no longer default under UTF-8 locales
+
+=item Unsafe signals again available
+
+=item Tied Arrays with Negative Array Indices
+
+=item local ${$x}
+
+=item Unicode Character Database 4.0.0
+
+=item Miscellaneous Enhancements
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Updated Modules And Pragmata
+
+base, B::Bytecode, B::Concise, B::Deparse, Benchmark, ByteLoader, bytes,
+CGI, charnames, CPAN, Data::Dumper, DB_File, Devel::PPPort, Digest::MD5,
+Encode, fields, libnet, Math::BigInt, MIME::Base64, NEXT, Net::Ping,
+PerlIO::scalar, podlators, Pod::LaTeX, PodParsers, Pod::Perldoc,
+Scalar::Util, Storable, strict, Term::ANSIcolor, Test::Harness, Test::More,
+Test::Simple, Text::Balanced, Time::HiRes, threads, threads::shared,
+Unicode::Collate, Unicode::Normalize, Win32::GetFolderPath,
+Win32::GetOSVersion
+
+=back
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Platform-specific enhancements
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Closures, eval and lexicals
+
+=item Generic fixes
+
+=item Platform-specific fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item Changed "A thread exited while %d threads were running"
+
+=item Removed "Attempt to clear a restricted hash"
+
+=item New "Illegal declaration of anonymous subroutine"
+
+=item Changed "Invalid range "%s" in transliteration operator"
+
+=item New "Missing control char name in \c"
+
+=item New "Newline in left-justified string for %s"
+
+=item New "Possible precedence problem on bitwise %c operator"
+
+=item New "read() on %s filehandle %s"
+
+=item New "Tied variable freed while still in use"
+
+=item New "To%s: illegal mapping '%s'"
+
+=item New "Use of freed value in iteration"
+
+=back
+
+=item Changed Internals
+
+=item New Tests
+
+=item Known Problems
+
+=over 4
+
+=item Tied hashes in scalar context
+
+=item Net::Ping 450_service and 510_ping_udp failures
+
+=item B::C
+
+=back
+
+=item Platform Specific Problems
+
+=over 4
+
+=item EBCDIC Platforms
+
+=item Cygwin 1.5 problems
+
+=item HP-UX: HP cc warnings about sendfile and sendpath
+
+=item IRIX: t/uni/tr_7jis.t falsely failing
+
+=item Mac OS X: no usemymalloc
+
+=item Tru64: No threaded builds with GNU cc (gcc)
+
+=item Win32: sysopen, sysread, syswrite
+
+=back
+
+=item TODO
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl589delta - what is new for perl v5.8.9
+
+=over 4
+
+=item DESCRIPTION
+
+=item Notice
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode Character Database 5.1.0.
+
+=item stat and -X on directory handles
+
+=item Source filters in @INC
+
+=item Exceptions in constant folding
+
+=item C<no VERSION>
+
+=item Improved internal UTF-8 caching code
+
+=item Runtime relocatable installations
+
+=item New internal variables
+
+C<${^CHILD_ERROR_NATIVE}>, C<${^UTF8CACHE}>
+
+=item C<readpipe> is now overridable
+
+=item simple exception handling macros
+
+=item -D option enhancements
+
+=item XS-assisted SWASHGET
+
+=item Constant subroutines
+
+=back
+
+=item New Platforms
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules
+
+=item Updated Modules
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item debugger upgraded to version 1.31
+
+=item F<perlthanks>
+
+=item F<perlbug>
+
+=item F<h2xs>
+
+=item F<h2ph>
+
+=back
+
+=item New Documentation
+
+=item Changes to Existing Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Relocatable installations
+
+=item Configuration improvements
+
+=item Compilation improvements
+
+=item Installation improvements.
+
+=item Platform Specific Changes
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Unicode
+
+=item PerlIO
+
+=item Magic
+
+=item Reblessing overloaded objects now works
+
+=item C<strict> now propagates correctly into string evals
+
+=item Other fixes
+
+=item Platform Specific Fixes
+
+=item Smaller fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item panic: sv_chop %s
+
+=item Maximal count of pending signals (%s) exceeded
+
+=item panic: attempt to call %s in %s
+
+=item FETCHSIZE returned a negative value
+
+=item Can't upgrade %s (%d) to %d
+
+=item %s argument is not a HASH or ARRAY element or a subroutine
+
+=item Cannot make the non-overridable builtin %s fatal
+
+=item Unrecognized character '%s' in column %d
+
+=item Offset outside string
+
+=item Invalid escape in the specified encoding in regexp; marked by <--
+HERE in m/%s/
+
+=item Your machine doesn't support dump/undump.
+
+=back
+
+=item Changed Internals
+
+=over 4
+
+=item Macro cleanups
+
+=back
+
+=item New Tests
+
+ext/DynaLoader/t/DynaLoader.t, t/comp/fold.t, t/io/pvbm.t,
+t/lib/proxy_constant_subs.t, t/op/attrhand.t, t/op/dbm.t,
+t/op/inccode-tie.t, t/op/incfilter.t, t/op/kill0.t, t/op/qrstack.t,
+t/op/qr.t, t/op/regexp_qr_embed.t, t/op/regexp_qr.t, t/op/rxcode.t,
+t/op/studytied.t, t/op/substT.t, t/op/symbolcache.t, t/op/upgrade.t,
+t/mro/package_aliases.t, t/pod/twice.t, t/run/cloexec.t, t/uni/cache.t,
+t/uni/chr.t, t/uni/greek.t, t/uni/latin2.t, t/uni/overload.t, t/uni/tie.t
+
+=item Known Problems
+
+=item Platform Specific Notes
+
+=over 4
+
+=item Win32
+
+=item OS/2
+
+=item VMS
+
+=back
+
+=item Obituary
+
+=item Acknowledgements
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl588delta - what is new for perl v5.8.8
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=item Utility Changes
+
+=over 4
+
+=item C<h2xs> enhancements
+
+=item C<perlivp> enhancements
+
+=back
+
+=item New Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item no warnings 'category' works correctly with -w
+
+=item Remove over-optimisation
+
+=item sprintf() fixes
+
+=item Debugger and Unicode slowdown
+
+=item Smaller fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item Attempt to set length of freed array
+
+=item Non-string passed as bitmask
+
+=item Search pattern not terminated or ternary operator parsed as search
+pattern
+
+=back
+
+=item Changed Internals
+
+=item Platform Specific Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl587delta - what is new for perl v5.8.7
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode Character Database 4.1.0
+
+=item suidperl less insecure
+
+=item Optional site customization script
+
+=item C<Config.pm> is now much smaller.
+
+=back
+
+=item Modules and Pragmata
+
+=item Utility Changes
+
+=over 4
+
+=item find2perl enhancements
+
+=back
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Known Problems
+
+=item Platform Specific Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl586delta - what is new for perl v5.8.6
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=item Utility Changes
+
+=item Performance Enhancements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item New Tests
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl585delta - what is new for perl v5.8.5
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=item Utility Changes
+
+=over 4
+
+=item Perl's debugger
+
+=item h2ph
+
+=back
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Known Problems
+
+=item Platform Specific Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl584delta - what is new for perl v5.8.4
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item Malloc wrapping
+
+=item Unicode Character Database 4.0.1
+
+=item suidperl less insecure
+
+=item format
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Updated modules
+
+Attribute::Handlers, B, Benchmark, CGI, Carp, Cwd, Exporter, File::Find,
+IO, IPC::Open3, Local::Maketext, Math::BigFloat, Math::BigInt,
+Math::BigRat, MIME::Base64, ODBM_File, POSIX, Shell, Socket, Storable,
+Switch, Sys::Syslog, Term::ANSIColor, Time::HiRes, Unicode::UCD, Win32,
+base, open, threads, utf8
+
+=back
+
+=item Performance Enhancements
+
+=item Utility Changes
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Future Directions
+
+=item Platform Specific Problems
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl583delta - what is new for perl v5.8.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+CGI, Cwd, Digest, Digest::MD5, Encode, File::Spec, FindBin, List::Util,
+Math::BigInt, PodParser, Pod::Perldoc, POSIX, Unicode::Collate,
+Unicode::Normalize, Test::Harness, threads::shared
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Installation and Configuration Improvements
+
+=item Selected Bug Fixes
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Configuration and Building
+
+=item Platform Specific Problems
+
+=item Known Problems
+
+=item Future Directions
+
+=item Obituary
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl582delta - what is new for perl v5.8.2
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item Hash Randomisation
+
+=item Threading
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Updated Modules And Pragmata
+
+Devel::PPPort, Digest::MD5, I18N::LangTags, libnet, MIME::Base64,
+Pod::Perldoc, strict, Tie::Hash, Time::HiRes, Unicode::Collate,
+Unicode::Normalize, UNIVERSAL
+
+=back
+
+=item Selected Bug Fixes
+
+=item Changed Internals
+
+=item Platform Specific Problems
+
+=item Future Directions
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl581delta - what is new for perl v5.8.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Incompatible Changes
+
+=over 4
+
+=item Hash Randomisation
+
+=item UTF-8 On Filehandles No Longer Activated By Locale
+
+=item Single-number v-strings are no longer v-strings before "=>"
+
+=item (Win32) The -C Switch Has Been Repurposed
+
+=item (Win32) The /d Switch Of cmd.exe
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item UTF-8 no longer default under UTF-8 locales
+
+=item Unsafe signals again available
+
+=item Tied Arrays with Negative Array Indices
+
+=item local ${$x}
+
+=item Unicode Character Database 4.0.0
+
+=item Deprecation Warnings
+
+=item Miscellaneous Enhancements
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Updated Modules And Pragmata
+
+base, B::Bytecode, B::Concise, B::Deparse, Benchmark, ByteLoader, bytes,
+CGI, charnames, CPAN, Data::Dumper, DB_File, Devel::PPPort, Digest::MD5,
+Encode, fields, libnet, Math::BigInt, MIME::Base64, NEXT, Net::Ping,
+PerlIO::scalar, podlators, Pod::LaTeX, PodParsers, Pod::Perldoc,
+Scalar::Util, Storable, strict, Term::ANSIcolor, Test::Harness, Test::More,
+Test::Simple, Text::Balanced, Time::HiRes, threads, threads::shared,
+Unicode::Collate, Unicode::Normalize, Win32::GetFolderPath,
+Win32::GetOSVersion
+
+=back
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Platform-specific enhancements
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Closures, eval and lexicals
+
+=item Generic fixes
+
+=item Platform-specific fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=over 4
+
+=item Changed "A thread exited while %d threads were running"
+
+=item Removed "Attempt to clear a restricted hash"
+
+=item New "Illegal declaration of anonymous subroutine"
+
+=item Changed "Invalid range "%s" in transliteration operator"
+
+=item New "Missing control char name in \c"
+
+=item New "Newline in left-justified string for %s"
+
+=item New "Possible precedence problem on bitwise %c operator"
+
+=item New "Pseudo-hashes are deprecated"
+
+=item New "read() on %s filehandle %s"
+
+=item New "5.005 threads are deprecated"
+
+=item New "Tied variable freed while still in use"
+
+=item New "To%s: illegal mapping '%s'"
+
+=item New "Use of freed value in iteration"
+
+=back
+
+=item Changed Internals
+
+=item New Tests
+
+=item Known Problems
+
+=over 4
+
+=item Tied hashes in scalar context
+
+=item Net::Ping 450_service and 510_ping_udp failures
+
+=item B::C
+
+=back
+
+=item Platform Specific Problems
+
+=over 4
+
+=item EBCDIC Platforms
+
+=item Cygwin 1.5 problems
+
+=item HP-UX: HP cc warnings about sendfile and sendpath
+
+=item IRIX: t/uni/tr_7jis.t falsely failing
+
+=item Mac OS X: no usemymalloc
+
+=item Tru64: No threaded builds with GNU cc (gcc)
+
+=item Win32: sysopen, sysread, syswrite
+
+=back
+
+=item Future Directions
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=back
+
+=head2 perl58delta - what is new for perl v5.8.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Highlights In 5.8.0
+
+=item Incompatible Changes
+
+=over 4
+
+=item Binary Incompatibility
+
+=item 64-bit platforms and malloc
+
+=item AIX Dynaloading
+
+=item Attributes for C<my> variables now handled at run-time
+
+=item Socket Extension Dynamic in VMS
+
+=item IEEE-format Floating Point Default on OpenVMS Alpha
+
+=item New Unicode Semantics (no more C<use utf8>, almost)
+
+=item New Unicode Properties
+
+=item REF(...) Instead Of SCALAR(...)
+
+=item pack/unpack D/F recycled
+
+=item glob() now returns filenames in alphabetical order
+
+=item Deprecations
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Unicode Overhaul
+
+=item PerlIO is Now The Default
+
+=item ithreads
+
+=item Restricted Hashes
+
+=item Safe Signals
+
+=item Understanding of Numbers
+
+=item Arrays now always interpolate into double-quoted strings [561]
+
+=item Miscellaneous Changes
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Pragmata
+
+=item Updated And Improved Modules and Pragmata
+
+=back
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Generic Improvements
+
+=item New Or Improved Platforms
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Platform Specific Changes and Fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Security Vulnerability Closed [561]
+
+=item New Tests
+
+=item Known Problems
+
+=over 4
+
+=item The Compiler Suite Is Still Very Experimental
+
+=item Localising Tied Arrays and Hashes Is Broken
+
+=item Building Extensions Can Fail Because Of Largefiles
+
+=item Modifying $_ Inside for(..)
+
+=item mod_perl 1.26 Doesn't Build With Threaded Perl
+
+=item lib/ftmp-security tests warn 'system possibly insecure'
+
+=item libwww-perl (LWP) fails base/date #51
+
+=item PDL failing some tests
+
+=item Perl_get_sv
+
+=item Self-tying Problems
+
+=item ext/threads/t/libc
+
+=item Failure of Thread (5.005-style) tests
+
+=item Timing problems
+
+=item Tied/Magical Array/Hash Elements Do Not Autovivify
+
+=item Unicode in package/class and subroutine names does not work
+
+=back
+
+=item Platform Specific Problems
+
+=over 4
+
+=item AIX
+
+=item Alpha systems with old gccs fail several tests
+
+=item AmigaOS
+
+=item BeOS
+
+=item Cygwin "unable to remap"
+
+=item Cygwin ndbm tests fail on FAT
+
+=item DJGPP Failures
+
+=item FreeBSD built with ithreads coredumps reading large directories
+
+=item FreeBSD Failing locale Test 117 For ISO 8859-15 Locales
+
+=item IRIX fails ext/List/Util/t/shuffle.t or Digest::MD5
+
+=item HP-UX lib/posix Subtest 9 Fails When LP64-Configured
+
+=item Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint
+
+=item Linux With Sfio Fails op/misc Test 48
+
+=item Mac OS X
+
+=item Mac OS X dyld undefined symbols
+
+=item OS/2 Test Failures
+
+=item op/sprintf tests 91, 129, and 130
+
+=item SCO
+
+=item Solaris 2.5
+
+=item Solaris x86 Fails Tests With -Duse64bitint
+
+=item SUPER-UX (NEC SX)
+
+=item Term::ReadKey not working on Win32
+
+=item UNICOS/mk
+
+=item UTS
+
+=item VOS (Stratus)
+
+=item VMS
+
+=item Win32
+
+=item XML::Parser not working
+
+=item z/OS (OS/390)
+
+=item Unicode Support on EBCDIC Still Spotty
+
+=item Seen In Perl 5.7 But Gone Now
+
+=back
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl573delta - what's new for perl v5.7.3
+
+=over 4
+
+=item DESCRIPTION
+
+=item Changes
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl572delta - what's new for perl v5.7.2
+
+=over 4
+
+=item DESCRIPTION
+
+=item Security Vulnerability Closed
+
+=item Incompatible Changes
+
+=over 4
+
+=item 64-bit platforms and malloc
+
+=item AIX Dynaloading
+
+=item Socket Extension Dynamic in VMS
+
+=item Different Definition of the Unicode Character Classes \p{In...}
+
+=item Deprecations
+
+=back
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules and Distributions
+
+=item Updated And Improved Modules and Pragmata
+
+=back
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item New Or Improved Platforms
+
+=item Generic Improvements
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Platform Specific Changes and Fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=item Source Code Enhancements
+
+=over 4
+
+=item MAGIC constants
+
+=item Better commented code
+
+=item Regex pre-/post-compilation items matched up
+
+=item gcc -Wall
+
+=back
+
+=item New Tests
+
+=item Known Problems
+
+=over 4
+
+=item AIX
+
+=item Amiga Perl Invoking Mystery
+
+=item lib/ftmp-security tests warn 'system possibly insecure'
+
+=item Cygwin intermittent failures of lib/Memoize/t/expire_file 11 and 12
+
+=item HP-UX lib/io_multihomed Fails When LP64-Configured
+
+=item HP-UX lib/posix Subtest 9 Fails When LP64-Configured
+
+=item Linux With Sfio Fails op/misc Test 48
+
+=item OS/390
+
+=item op/sprintf tests 129 and 130
+
+=item Failure of Thread tests
+
+=item UNICOS
+
+=item UTS
+
+=item VMS
+
+=item Win32
+
+=item Localising a Tied Variable Leaks Memory
+
+=item Self-tying of Arrays and Hashes Is Forbidden
+
+=item Variable Attributes are not Currently Usable for Tieing
+
+=item Building Extensions Can Fail Because Of Largefiles
+
+=item The Compiler Suite Is Still Experimental
+
+=item The Long Double Support is Still Experimental
+
+=back
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl571delta - what's new for perl v5.7.1
+
+=over 4
+
+=item DESCRIPTION
+
+=item Security Vulnerability Closed
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=over 4
+
+=item AUTOLOAD Is Now Lvaluable
+
+=item PerlIO is Now The Default
+
+=item Signals Are Now Safe
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules
+
+=item Updated And Improved Modules and Pragmata
+
+=back
+
+=item Performance Enhancements
+
+=item Utility Changes
+
+=item New Documentation
+
+=over 4
+
+=item perlclib
+
+=item perliol
+
+=item README.aix
+
+=item README.bs2000
+
+=item README.macos
+
+=item README.mpeix
+
+=item README.solaris
+
+=item README.vos
+
+=item Porting/repository.pod
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item New Or Improved Platforms
+
+=item Generic Improvements
+
+d_cmsghdr, d_fcntl_can_lock, d_fsync, d_getitimer, d_getpagsz, d_msghdr_s,
+need_va_copy, d_readv, d_recvmsg, d_sendmsg, sig_size, d_sockatmark,
+d_strtoq, d_u32align, d_ualarm, d_usleep
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Platform Specific Changes and Fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item New Tests
+
+=item Known Problems
+
+=over 4
+
+=item AIX vac 5.0.0.0 May Produce Buggy Code For Perl
+
+=item lib/ftmp-security tests warn 'system possibly insecure'
+
+=item lib/io_multihomed Fails In LP64-Configured HP-UX
+
+=item Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+
+=item lib/b test 19
+
+=item Linux With Sfio Fails op/misc Test 48
+
+=item sigaction test 13 in VMS
+
+=item sprintf tests 129 and 130
+
+=item Failure of Thread tests
+
+=item Localising a Tied Variable Leaks Memory
+
+=item Self-tying of Arrays and Hashes Is Forbidden
+
+=item Building Extensions Can Fail Because Of Largefiles
+
+=item The Compiler Suite Is Still Experimental
+
+=back
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl570delta - what's new for perl v5.7.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Security Vulnerability Closed
+
+=item Incompatible Changes
+
+=item Core Enhancements
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules
+
+=item Updated And Improved Modules and Pragmata
+
+=back
+
+=item Utility Changes
+
+=item New Documentation
+
+=item Performance Enhancements
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item Generic Improvements
+
+=back
+
+=item Selected Bug Fixes
+
+=over 4
+
+=item Platform Specific Changes and Fixes
+
+=back
+
+=item New or Changed Diagnostics
+
+=item Changed Internals
+
+=item Known Problems
+
+=over 4
+
+=item Unicode Support Still Far From Perfect
+
+=item EBCDIC Still A Lost Platform
+
+=item Building Extensions Can Fail Because Of Largefiles
+
+=item ftmp-security tests warn 'system possibly insecure'
+
+=item Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX
+
+=item Long Doubles Still Don't Work In Solaris
+
+=item Linux With Sfio Fails op/misc Test 48
+
+=item Storable tests fail in some platforms
+
+=item Threads Are Still Experimental
+
+=item The Compiler Suite Is Still Experimental
+
+=back
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl561delta - what's new for perl v5.6.x
+
+=over 4
+
+=item DESCRIPTION
+
+=item Summary of changes between 5.6.0 and 5.6.1
+
+=over 4
+
+=item Security Issues
+
+=item Core bug fixes
+
+C<UNIVERSAL::isa()>, Memory leaks, Numeric conversions, qw(a\\b), caller(),
+Bugs in regular expressions, "slurp" mode, Autovivification of symbolic
+references to special variables, Lexical warnings, Spurious warnings and
+errors, glob(), Tainting, sort(), #line directives, Subroutine prototypes,
+map(), Debugger, PERL5OPT, chop(), Unicode support, 64-bit support,
+Compiler, Lvalue subroutines, IO::Socket, File::Find, xsubpp, C<no
+Module;>, Tests
+
+=item Core features
+
+=item Configuration issues
+
+=item Documentation
+
+=item Bundled modules
+
+B::Concise, File::Temp, Pod::LaTeX, Pod::Text::Overstrike, CGI, CPAN,
+Class::Struct, DB_File, Devel::Peek, File::Find, Getopt::Long, IO::Poll,
+IPC::Open3, Math::BigFloat, Math::Complex, Net::Ping, Opcode, Pod::Parser,
+Pod::Text, SDBM_File, Sys::Syslog, Tie::RefHash, Tie::SubstrHash
+
+=item Platform-specific improvements
+
+NCR MP-RAS, NonStop-UX
+
+=back
+
+=item Core Enhancements
+
+=over 4
+
+=item Interpreter cloning, threads, and concurrency
+
+=item Lexically scoped warning categories
+
+=item Unicode and UTF-8 support
+
+=item Support for interpolating named characters
+
+=item "our" declarations
+
+=item Support for strings represented as a vector of ordinals
+
+=item Improved Perl version numbering system
+
+=item New syntax for declaring subroutine attributes
+
+=item File and directory handles can be autovivified
+
+=item open() with more than two arguments
+
+=item 64-bit support
+
+=item Large file support
+
+=item Long doubles
+
+=item "more bits"
+
+=item Enhanced support for sort() subroutines
+
+=item C<sort $coderef @foo> allowed
+
+=item File globbing implemented internally
+
+=item Support for CHECK blocks
+
+=item POSIX character class syntax [: :] supported
+
+=item Better pseudo-random number generator
+
+=item Improved C<qw//> operator
+
+=item Better worst-case behavior of hashes
+
+=item pack() format 'Z' supported
+
+=item pack() format modifier '!' supported
+
+=item pack() and unpack() support counted strings
+
+=item Comments in pack() templates
+
+=item Weak references
+
+=item Binary numbers supported
+
+=item Lvalue subroutines
+
+=item Some arrows may be omitted in calls through references
+
+=item Boolean assignment operators are legal lvalues
+
+=item exists() is supported on subroutine names
+
+=item exists() and delete() are supported on array elements
+
+=item Pseudo-hashes work better
+
+=item Automatic flushing of output buffers
+
+=item Better diagnostics on meaningless filehandle operations
+
+=item Where possible, buffered data discarded from duped input filehandle
+
+=item eof() has the same old magic as <>
+
+=item binmode() can be used to set :crlf and :raw modes
+
+=item C<-T> filetest recognizes UTF-8 encoded files as "text"
+
+=item system(), backticks and pipe open now reflect exec() failure
+
+=item Improved diagnostics
+
+=item Diagnostics follow STDERR
+
+=item More consistent close-on-exec behavior
+
+=item syswrite() ease-of-use
+
+=item Better syntax checks on parenthesized unary operators
+
+=item Bit operators support full native integer width
+
+=item Improved security features
+
+=item More functional bareword prototype (*)
+
+=item C<require> and C<do> may be overridden
+
+=item $^X variables may now have names longer than one character
+
+=item New variable $^C reflects C<-c> switch
+
+=item New variable $^V contains Perl version as a string
+
+=item Optional Y2K warnings
+
+=item Arrays now always interpolate into double-quoted strings
+
+=item @- and @+ provide starting/ending offsets of regex submatches
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Modules
+
+attributes, B, Benchmark, ByteLoader, constant, charnames, Data::Dumper,
+DB, DB_File, Devel::DProf, Devel::Peek, Dumpvalue, DynaLoader, English,
+Env, Fcntl, File::Compare, File::Find, File::Glob, File::Spec,
+File::Spec::Functions, Getopt::Long, IO, JPL, lib, Math::BigInt,
+Math::Complex, Math::Trig, Pod::Parser, Pod::InputObjects, Pod::Checker,
+podchecker, Pod::ParseUtils, Pod::Find, Pod::Select, podselect, Pod::Usage,
+pod2usage, Pod::Text and Pod::Man, SDBM_File, Sys::Syslog, Sys::Hostname,
+Term::ANSIColor, Time::Local, Win32, XSLoader, DBM Filters
+
+=item Pragmata
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item dprofpp
+
+=item find2perl
+
+=item h2xs
+
+=item perlcc
+
+=item perldoc
+
+=item The Perl Debugger
+
+=back
+
+=item Improved Documentation
+
+perlapi.pod, perlboot.pod, perlcompile.pod, perldbmfilter.pod,
+perldebug.pod, perldebguts.pod, perlfork.pod, perlfilter.pod, perlhack.pod,
+perlintern.pod, perllexwarn.pod, perlnumber.pod, perlopentut.pod,
+perlreftut.pod, perltootc.pod, perltodo.pod, perlunicode.pod
+
+=item Performance enhancements
+
+=over 4
+
+=item Simple sort() using { $a <=> $b } and the like are optimized
+
+=item Optimized assignments to lexical variables
+
+=item Faster subroutine calls
+
+=item delete(), each(), values() and hash iteration are faster
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item -Dusethreads means something different
+
+=item New Configure flags
+
+=item Threadedness and 64-bitness now more daring
+
+=item Long Doubles
+
+=item -Dusemorebits
+
+=item -Duselargefiles
+
+=item installusrbinperl
+
+=item SOCKS support
+
+=item C<-A> flag
+
+=item Enhanced Installation Directories
+
+=item gcc automatically tried if 'cc' does not seem to be working
+
+=back
+
+=item Platform specific changes
+
+=over 4
+
+=item Supported platforms
+
+=item DOS
+
+=item OS390 (OpenEdition MVS)
+
+=item VMS
+
+=item Win32
+
+=back
+
+=item Significant bug fixes
+
+=over 4
+
+=item <HANDLE> on empty files
+
+=item C<eval '...'> improvements
+
+=item All compilation errors are true errors
+
+=item Implicitly closed filehandles are safer
+
+=item Behavior of list slices is more consistent
+
+=item C<(\$)> prototype and C<$foo{a}>
+
+=item C<goto &sub> and AUTOLOAD
+
+=item C<-bareword> allowed under C<use integer>
+
+=item Failures in DESTROY()
+
+=item Locale bugs fixed
+
+=item Memory leaks
+
+=item Spurious subroutine stubs after failed subroutine calls
+
+=item Taint failures under C<-U>
+
+=item END blocks and the C<-c> switch
+
+=item Potential to leak DATA filehandles
+
+=back
+
+=item New or Changed Diagnostics
+
+"%s" variable %s masks earlier declaration in same %s, "my sub" not yet
+implemented, "our" variable %s redeclared, '!' allowed only after types %s,
+/ cannot take a count, / must be followed by a, A or Z, / must be followed
+by a*, A* or Z*, / must follow a numeric type, /%s/: Unrecognized escape
+\\%c passed through, /%s/: Unrecognized escape \\%c in character class
+passed through, /%s/ should probably be written as "%s", %s() called too
+early to check prototype, %s argument is not a HASH or ARRAY element, %s
+argument is not a HASH or ARRAY element or slice, %s argument is not a
+subroutine name, %s package attribute may clash with future reserved word:
+%s, (in cleanup) %s, <> should be quotes, Attempt to join self, Bad evalled
+substitution pattern, Bad realloc() ignored, Bareword found in conditional,
+Binary number > 0b11111111111111111111111111111111 non-portable, Bit vector
+size > 32 non-portable, Buffer overflow in prime_env_iter: %s, Can't check
+filesystem of script "%s", Can't declare class for non-scalar %s in "%s",
+Can't declare %s in "%s", Can't ignore signal CHLD, forcing to default,
+Can't modify non-lvalue subroutine call, Can't read CRTL environ, Can't
+remove %s: %s, skipping file, Can't return %s from lvalue subroutine, Can't
+weaken a nonreference, Character class [:%s:] unknown, Character class
+syntax [%s] belongs inside character classes, Constant is not %s reference,
+constant(%s): %s, CORE::%s is not a keyword, defined(@array) is deprecated,
+defined(%hash) is deprecated, Did not produce a valid header, (Did you mean
+"local" instead of "our"?), Document contains no data, entering effective
+%s failed, false [] range "%s" in regexp, Filehandle %s opened only for
+output, flock() on closed filehandle %s, Global symbol "%s" requires
+explicit package name, Hexadecimal number > 0xffffffff non-portable,
+Ill-formed CRTL environ value "%s", Ill-formed message in prime_env_iter:
+|%s|, Illegal binary digit %s, Illegal binary digit %s ignored, Illegal
+number of bits in vec, Integer overflow in %s number, Invalid %s attribute:
+%s, Invalid %s attributes: %s, invalid [] range "%s" in regexp, Invalid
+separator character %s in attribute list, Invalid separator character %s in
+subroutine attribute list, leaving effective %s failed, Lvalue subs
+returning %s not implemented yet, Method %s not permitted, Missing
+%sbrace%s on \N{}, Missing command in piped open, Missing name in "my sub",
+No %s specified for -%c, No package name allowed for variable %s in "our",
+No space allowed after -%c, no UTC offset information; assuming local time
+is UTC, Octal number > 037777777777 non-portable, panic: del_backref,
+panic: kid popen errno read, panic: magic_killbackrefs, Parentheses missing
+around "%s" list, Possible unintended interpolation of %s in string,
+Possible Y2K bug: %s, pragma "attrs" is deprecated, use "sub NAME : ATTRS"
+instead, Premature end of script headers, Repeat count in pack overflows,
+Repeat count in unpack overflows, realloc() of freed memory ignored,
+Reference is already weak, setpgrp can't take arguments, Strange *+?{} on
+zero-length expression, switching effective %s is not implemented, This
+Perl can't reset CRTL environ elements (%s), This Perl can't set CRTL
+environ elements (%s=%s), Too late to run %s block, Unknown open() mode
+'%s', Unknown process %x sent message to prime_env_iter: %s, Unrecognized
+escape \\%c passed through, Unterminated attribute parameter in attribute
+list, Unterminated attribute list, Unterminated attribute parameter in
+subroutine attribute list, Unterminated subroutine attribute list, Value of
+CLI symbol "%s" too long, Version number must be a constant number
+
+=item New tests
+
+=item Incompatible Changes
+
+=over 4
+
+=item Perl Source Incompatibilities
+
+CHECK is a new keyword, Treatment of list slices of undef has changed,
+Format of $English::PERL_VERSION is different, Literals of the form
+C<1.2.3> parse differently, Possibly changed pseudo-random number
+generator, Hashing function for hash keys has changed, C<undef> fails on
+read only values, Close-on-exec bit may be set on pipe and socket handles,
+Writing C<"$$1"> to mean C<"${$}1"> is unsupported, delete(), each(),
+values() and C<\(%h)>, vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS,
+Text of some diagnostic output has changed, C<%@> has been removed,
+Parenthesized not() behaves like a list operator, Semantics of bareword
+prototype C<(*)> have changed, Semantics of bit operators may have changed
+on 64-bit platforms, More builtins taint their results
+
+=item C Source Incompatibilities
+
+C<PERL_POLLUTE>, C<PERL_IMPLICIT_CONTEXT>, C<PERL_POLLUTE_MALLOC>
+
+=item Compatible C Source API Changes
+
+C<PATCHLEVEL> is now C<PERL_VERSION>
+
+=item Binary Incompatibilities
+
+=back
+
+=item Known Problems
+
+=over 4
+
+=item Localizing a tied hash element may leak memory
+
+=item Known test failures
+
+=item EBCDIC platforms not fully supported
+
+=item UNICOS/mk CC failures during Configure run
+
+=item Arrow operator and arrays
+
+=item Experimental features
+
+Threads, Unicode, 64-bit support, Lvalue subroutines, Weak references, The
+pseudo-hash data type, The Compiler suite, Internal implementation of file
+globbing, The DB module, The regular expression code constructs:
+
+=back
+
+=item Obsolete Diagnostics
+
+Character class syntax [: :] is reserved for future extensions, Ill-formed
+logical name |%s| in prime_env_iter, In string, @%s now must be written as
+\@%s, Probable precedence problem on %s, regexp too big, Use of "$$<digit>"
+to mean "${$}<digit>" is deprecated
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl56delta - what's new for perl v5.6.0
+
+=over 4
+
+=item DESCRIPTION
+
+=item Core Enhancements
+
+=over 4
+
+=item Interpreter cloning, threads, and concurrency
+
+=item Lexically scoped warning categories
+
+=item Unicode and UTF-8 support
+
+=item Support for interpolating named characters
+
+=item "our" declarations
+
+=item Support for strings represented as a vector of ordinals
+
+=item Improved Perl version numbering system
+
+=item New syntax for declaring subroutine attributes
+
+=item File and directory handles can be autovivified
+
+=item open() with more than two arguments
+
+=item 64-bit support
+
+=item Large file support
+
+=item Long doubles
+
+=item "more bits"
+
+=item Enhanced support for sort() subroutines
+
+=item C<sort $coderef @foo> allowed
+
+=item File globbing implemented internally
+
+=item Support for CHECK blocks
+
+=item POSIX character class syntax [: :] supported
+
+=item Better pseudo-random number generator
+
+=item Improved C<qw//> operator
+
+=item Better worst-case behavior of hashes
+
+=item pack() format 'Z' supported
+
+=item pack() format modifier '!' supported
+
+=item pack() and unpack() support counted strings
+
+=item Comments in pack() templates
+
+=item Weak references
+
+=item Binary numbers supported
+
+=item Lvalue subroutines
+
+=item Some arrows may be omitted in calls through references
+
+=item Boolean assignment operators are legal lvalues
+
+=item exists() is supported on subroutine names
+
+=item exists() and delete() are supported on array elements
+
+=item Pseudo-hashes work better
+
+=item Automatic flushing of output buffers
+
+=item Better diagnostics on meaningless filehandle operations
+
+=item Where possible, buffered data discarded from duped input filehandle
+
+=item eof() has the same old magic as <>
+
+=item binmode() can be used to set :crlf and :raw modes
+
+=item C<-T> filetest recognizes UTF-8 encoded files as "text"
+
+=item system(), backticks and pipe open now reflect exec() failure
+
+=item Improved diagnostics
+
+=item Diagnostics follow STDERR
+
+=item More consistent close-on-exec behavior
+
+=item syswrite() ease-of-use
+
+=item Better syntax checks on parenthesized unary operators
+
+=item Bit operators support full native integer width
+
+=item Improved security features
+
+=item More functional bareword prototype (*)
+
+=item C<require> and C<do> may be overridden
+
+=item $^X variables may now have names longer than one character
+
+=item New variable $^C reflects C<-c> switch
+
+=item New variable $^V contains Perl version as a string
+
+=item Optional Y2K warnings
+
+=item Arrays now always interpolate into double-quoted strings
+
+=item @- and @+ provide starting/ending offsets of regex matches
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item Modules
+
+attributes, B, Benchmark, ByteLoader, constant, charnames, Data::Dumper,
+DB, DB_File, Devel::DProf, Devel::Peek, Dumpvalue, DynaLoader, English,
+Env, Fcntl, File::Compare, File::Find, File::Glob, File::Spec,
+File::Spec::Functions, Getopt::Long, IO, JPL, lib, Math::BigInt,
+Math::Complex, Math::Trig, Pod::Parser, Pod::InputObjects, Pod::Checker,
+podchecker, Pod::ParseUtils, Pod::Find, Pod::Select, podselect, Pod::Usage,
+pod2usage, Pod::Text and Pod::Man, SDBM_File, Sys::Syslog, Sys::Hostname,
+Term::ANSIColor, Time::Local, Win32, XSLoader, DBM Filters
+
+=item Pragmata
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item dprofpp
+
+=item find2perl
+
+=item h2xs
+
+=item perlcc
+
+=item perldoc
+
+=item The Perl Debugger
+
+=back
+
+=item Improved Documentation
+
+perlapi.pod, perlboot.pod, perlcompile.pod, perldbmfilter.pod,
+perldebug.pod, perldebguts.pod, perlfork.pod, perlfilter.pod, perlhack.pod,
+perlintern.pod, perllexwarn.pod, perlnumber.pod, perlopentut.pod,
+perlreftut.pod, perltootc.pod, perltodo.pod, perlunicode.pod
+
+=item Performance enhancements
+
+=over 4
+
+=item Simple sort() using { $a <=> $b } and the like are optimized
+
+=item Optimized assignments to lexical variables
+
+=item Faster subroutine calls
+
+=item delete(), each(), values() and hash iteration are faster
+
+=back
+
+=item Installation and Configuration Improvements
+
+=over 4
+
+=item -Dusethreads means something different
+
+=item New Configure flags
+
+=item Threadedness and 64-bitness now more daring
+
+=item Long Doubles
+
+=item -Dusemorebits
+
+=item -Duselargefiles
+
+=item installusrbinperl
+
+=item SOCKS support
+
+=item C<-A> flag
+
+=item Enhanced Installation Directories
+
+=back
+
+=item Platform specific changes
+
+=over 4
+
+=item Supported platforms
+
+=item DOS
+
+=item OS390 (OpenEdition MVS)
+
+=item VMS
+
+=item Win32
+
+=back
+
+=item Significant bug fixes
+
+=over 4
+
+=item <HANDLE> on empty files
+
+=item C<eval '...'> improvements
+
+=item All compilation errors are true errors
+
+=item Implicitly closed filehandles are safer
+
+=item Behavior of list slices is more consistent
+
+=item C<(\$)> prototype and C<$foo{a}>
+
+=item C<goto &sub> and AUTOLOAD
+
+=item C<-bareword> allowed under C<use integer>
+
+=item Failures in DESTROY()
+
+=item Locale bugs fixed
+
+=item Memory leaks
+
+=item Spurious subroutine stubs after failed subroutine calls
+
+=item Taint failures under C<-U>
+
+=item END blocks and the C<-c> switch
+
+=item Potential to leak DATA filehandles
+
+=back
+
+=item New or Changed Diagnostics
+
+"%s" variable %s masks earlier declaration in same %s, "my sub" not yet
+implemented, "our" variable %s redeclared, '!' allowed only after types %s,
+/ cannot take a count, / must be followed by a, A or Z, / must be followed
+by a*, A* or Z*, / must follow a numeric type, /%s/: Unrecognized escape
+\\%c passed through, /%s/: Unrecognized escape \\%c in character class
+passed through, /%s/ should probably be written as "%s", %s() called too
+early to check prototype, %s argument is not a HASH or ARRAY element, %s
+argument is not a HASH or ARRAY element or slice, %s argument is not a
+subroutine name, %s package attribute may clash with future reserved word:
+%s, (in cleanup) %s, <> should be quotes, Attempt to join self, Bad evalled
+substitution pattern, Bad realloc() ignored, Bareword found in conditional,
+Binary number > 0b11111111111111111111111111111111 non-portable, Bit vector
+size > 32 non-portable, Buffer overflow in prime_env_iter: %s, Can't check
+filesystem of script "%s", Can't declare class for non-scalar %s in "%s",
+Can't declare %s in "%s", Can't ignore signal CHLD, forcing to default,
+Can't modify non-lvalue subroutine call, Can't read CRTL environ, Can't
+remove %s: %s, skipping file, Can't return %s from lvalue subroutine, Can't
+weaken a nonreference, Character class [:%s:] unknown, Character class
+syntax [%s] belongs inside character classes, Constant is not %s reference,
+constant(%s): %s, CORE::%s is not a keyword, defined(@array) is deprecated,
+defined(%hash) is deprecated, Did not produce a valid header, (Did you mean
+"local" instead of "our"?), Document contains no data, entering effective
+%s failed, false [] range "%s" in regexp, Filehandle %s opened only for
+output, flock() on closed filehandle %s, Global symbol "%s" requires
+explicit package name, Hexadecimal number > 0xffffffff non-portable,
+Ill-formed CRTL environ value "%s", Ill-formed message in prime_env_iter:
+|%s|, Illegal binary digit %s, Illegal binary digit %s ignored, Illegal
+number of bits in vec, Integer overflow in %s number, Invalid %s attribute:
+%s, Invalid %s attributes: %s, invalid [] range "%s" in regexp, Invalid
+separator character %s in attribute list, Invalid separator character %s in
+subroutine attribute list, leaving effective %s failed, Lvalue subs
+returning %s not implemented yet, Method %s not permitted, Missing
+%sbrace%s on \N{}, Missing command in piped open, Missing name in "my sub",
+No %s specified for -%c, No package name allowed for variable %s in "our",
+No space allowed after -%c, no UTC offset information; assuming local time
+is UTC, Octal number > 037777777777 non-portable, panic: del_backref,
+panic: kid popen errno read, panic: magic_killbackrefs, Parentheses missing
+around "%s" list, Possible unintended interpolation of %s in string,
+Possible Y2K bug: %s, pragma "attrs" is deprecated, use "sub NAME : ATTRS"
+instead, Premature end of script headers, Repeat count in pack overflows,
+Repeat count in unpack overflows, realloc() of freed memory ignored,
+Reference is already weak, setpgrp can't take arguments, Strange *+?{} on
+zero-length expression, switching effective %s is not implemented, This
+Perl can't reset CRTL environ elements (%s), This Perl can't set CRTL
+environ elements (%s=%s), Too late to run %s block, Unknown open() mode
+'%s', Unknown process %x sent message to prime_env_iter: %s, Unrecognized
+escape \\%c passed through, Unterminated attribute parameter in attribute
+list, Unterminated attribute list, Unterminated attribute parameter in
+subroutine attribute list, Unterminated subroutine attribute list, Value of
+CLI symbol "%s" too long, Version number must be a constant number
+
+=item New tests
+
+=item Incompatible Changes
+
+=over 4
+
+=item Perl Source Incompatibilities
+
+CHECK is a new keyword, Treatment of list slices of undef has changed,
+Format of $English::PERL_VERSION is different, Literals of the form
+C<1.2.3> parse differently, Possibly changed pseudo-random number
+generator, Hashing function for hash keys has changed, C<undef> fails on
+read only values, Close-on-exec bit may be set on pipe and socket handles,
+Writing C<"$$1"> to mean C<"${$}1"> is unsupported, delete(), each(),
+values() and C<\(%h)>, vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS,
+Text of some diagnostic output has changed, C<%@> has been removed,
+Parenthesized not() behaves like a list operator, Semantics of bareword
+prototype C<(*)> have changed, Semantics of bit operators may have changed
+on 64-bit platforms, More builtins taint their results
+
+=item C Source Incompatibilities
+
+C<PERL_POLLUTE>, C<PERL_IMPLICIT_CONTEXT>, C<PERL_POLLUTE_MALLOC>
+
+=item Compatible C Source API Changes
+
+C<PATCHLEVEL> is now C<PERL_VERSION>
+
+=item Binary Incompatibilities
+
+=back
+
+=item Known Problems
+
+=over 4
+
+=item Thread test failures
+
+=item EBCDIC platforms not supported
+
+=item In 64-bit HP-UX the lib/io_multihomed test may hang
+
+=item NEXTSTEP 3.3 POSIX test failure
+
+=item Tru64 (aka Digital UNIX, aka DEC OSF/1) lib/sdbm test failure with
+gcc
+
+=item UNICOS/mk CC failures during Configure run
+
+=item Arrow operator and arrays
+
+=item Experimental features
+
+Threads, Unicode, 64-bit support, Lvalue subroutines, Weak references, The
+pseudo-hash data type, The Compiler suite, Internal implementation of file
+globbing, The DB module, The regular expression code constructs:
+
+=back
+
+=item Obsolete Diagnostics
+
+Character class syntax [: :] is reserved for future extensions, Ill-formed
+logical name |%s| in prime_env_iter, In string, @%s now must be written as
+\@%s, Probable precedence problem on %s, regexp too big, Use of "$$<digit>"
+to mean "${$}<digit>" is deprecated
+
+=item Reporting Bugs
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl5005delta - what's new for perl5.005
+
+=over 4
+
+=item DESCRIPTION
+
+=item About the new versioning system
+
+=item Incompatible Changes
+
+=over 4
+
+=item WARNING: This version is not binary compatible with Perl 5.004.
+
+=item Default installation structure has changed
+
+=item Perl Source Compatibility
+
+=item C Source Compatibility
+
+=item Binary Compatibility
+
+=item Security fixes may affect compatibility
+
+=item Relaxed new mandatory warnings introduced in 5.004
+
+=item Licensing
+
+=back
+
+=item Core Changes
+
+=over 4
+
+=item Threads
+
+=item Compiler
+
+=item Regular Expressions
+
+Many new and improved optimizations, Many bug fixes, New regular expression
+constructs, New operator for precompiled regular expressions, Other
+improvements, Incompatible changes
+
+=item Improved malloc()
+
+=item Quicksort is internally implemented
+
+=item Reliable signals
+
+=item Reliable stack pointers
+
+=item More generous treatment of carriage returns
+
+=item Memory leaks
+
+=item Better support for multiple interpreters
+
+=item Behavior of local() on array and hash elements is now well-defined
+
+=item C<%!> is transparently tied to the L<Errno> module
+
+=item Pseudo-hashes are supported
+
+=item C<EXPR foreach EXPR> is supported
+
+=item Keywords can be globally overridden
+
+=item C<$^E> is meaningful on Win32
+
+=item C<foreach (1..1000000)> optimized
+
+=item C<Foo::> can be used as implicitly quoted package name
+
+=item C<exists $Foo::{Bar::}> tests existence of a package
+
+=item Better locale support
+
+=item Experimental support for 64-bit platforms
+
+=item prototype() returns useful results on builtins
+
+=item Extended support for exception handling
+
+=item Re-blessing in DESTROY() supported for chaining DESTROY() methods
+
+=item All C<printf> format conversions are handled internally
+
+=item New C<INIT> keyword
+
+=item New C<lock> keyword
+
+=item New C<qr//> operator
+
+=item C<our> is now a reserved word
+
+=item Tied arrays are now fully supported
+
+=item Tied handles support is better
+
+=item 4th argument to substr
+
+=item Negative LENGTH argument to splice
+
+=item Magic lvalues are now more magical
+
+=item <> now reads in records
+
+=back
+
+=item Supported Platforms
+
+=over 4
+
+=item New Platforms
+
+=item Changes in existing support
+
+=back
+
+=item Modules and Pragmata
+
+=over 4
+
+=item New Modules
+
+B, Data::Dumper, Dumpvalue, Errno, File::Spec, ExtUtils::Installed,
+ExtUtils::Packlist, Fatal, IPC::SysV, Test, Tie::Array, Tie::Handle,
+Thread, attrs, fields, re
+
+=item Changes in existing modules
+
+Benchmark, Carp, CGI, Fcntl, Math::Complex, Math::Trig, POSIX, DB_File,
+MakeMaker, CPAN, Cwd
+
+=back
+
+=item Utility Changes
+
+=item Documentation Changes
+
+=item New Diagnostics
+
+Ambiguous call resolved as CORE::%s(), qualify as such or use &, Bad index
+while coercing array into hash, Bareword "%s" refers to nonexistent
+package, Can't call method "%s" on an undefined value, Can't check
+filesystem of script "%s" for nosuid, Can't coerce array into hash, Can't
+goto subroutine from an eval-string, Can't localize pseudo-hash element,
+Can't use %%! because Errno.pm is not available, Cannot find an opnumber
+for "%s", Character class syntax [. .] is reserved for future extensions,
+Character class syntax [: :] is reserved for future extensions, Character
+class syntax [= =] is reserved for future extensions, %s: Eval-group in
+insecure regular expression, %s: Eval-group not allowed, use re 'eval', %s:
+Eval-group not allowed at run time, Explicit blessing to '' (assuming
+package main), Illegal hex digit ignored, No such array field, No such
+field "%s" in variable %s of type %s, Out of memory during ridiculously
+large request, Range iterator outside integer range, Recursive inheritance
+detected while looking for method '%s' %s, Reference found where even-sized
+list expected, Undefined value assigned to typeglob, Use of reserved word
+"%s" is deprecated, perl: warning: Setting locale failed
+
+=item Obsolete Diagnostics
+
+Can't mktemp(), Can't write to temp file for B<-e>: %s, Cannot open
+temporary file, regexp too big
+
+=item Configuration Changes
+
+=item BUGS
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perl5004delta - what's new for perl5.004
+
+=over 4
+
+=item DESCRIPTION
+
+=item Supported Environments
+
+=item Core Changes
+
+=over 4
+
+=item List assignment to %ENV works
+
+=item Change to "Can't locate Foo.pm in @INC" error
+
+=item Compilation option: Binary compatibility with 5.003
+
+=item $PERL5OPT environment variable
+
+=item Limitations on B<-M>, B<-m>, and B<-T> options
+
+=item More precise warnings
+
+=item Deprecated: Inherited C<AUTOLOAD> for non-methods
+
+=item Previously deprecated %OVERLOAD is no longer usable
+
+=item Subroutine arguments created only when they're modified
+
+=item Group vector changeable with C<$)>
+
+=item Fixed parsing of $$<digit>, &$<digit>, etc.
+
+=item Fixed localization of $<digit>, $&, etc.
+
+=item No resetting of $. on implicit close
+
+=item C<wantarray> may return undef
+
+=item C<eval EXPR> determines value of EXPR in scalar context
+
+=item Changes to tainting checks
+
+No glob() or <*>, No spawning if tainted $CDPATH, $ENV, $BASH_ENV, No
+spawning if tainted $TERM doesn't look like a terminal name
+
+=item New Opcode module and revised Safe module
+
+=item Embedding improvements
+
+=item Internal change: FileHandle class based on IO::* classes
+
+=item Internal change: PerlIO abstraction interface
+
+=item New and changed syntax
+
+$coderef->(PARAMS)
+
+=item New and changed builtin constants
+
+__PACKAGE__
+
+=item New and changed builtin variables
+
+$^E, $^H, $^M
+
+=item New and changed builtin functions
+
+delete on slices, flock, printf and sprintf, keys as an lvalue, my() in
+Control Structures, pack() and unpack(), sysseek(), use VERSION, use Module
+VERSION LIST, prototype(FUNCTION), srand, $_ as Default, C<m//gc> does not
+reset search position on failure, C<m//x> ignores whitespace before ?*+{},
+nested C<sub{}> closures work now, formats work right on changing lexicals
+
+=item New builtin methods
+
+isa(CLASS), can(METHOD), VERSION( [NEED] )
+
+=item TIEHANDLE now supported
+
+TIEHANDLE classname, LIST, PRINT this, LIST, PRINTF this, LIST, READ this
+LIST, READLINE this, GETC this, DESTROY this
+
+=item Malloc enhancements
+
+-DPERL_EMERGENCY_SBRK, -DPACK_MALLOC, -DTWO_POT_OPTIMIZE
+
+=item Miscellaneous efficiency enhancements
+
+=back
+
+=item Support for More Operating Systems
+
+=over 4
+
+=item Win32
+
+=item Plan 9
+
+=item QNX
+
+=item AmigaOS
+
+=back
+
+=item Pragmata
+
+use autouse MODULE => qw(sub1 sub2 sub3), use blib, use blib 'dir', use
+constant NAME => VALUE, use locale, use ops, use vmsish
+
+=item Modules
+
+=over 4
+
+=item Required Updates
+
+=item Installation directories
+
+=item Module information summary
+
+=item Fcntl
+
+=item IO
+
+=item Math::Complex
+
+=item Math::Trig
+
+=item DB_File
+
+=item Net::Ping
+
+=item Object-oriented overrides for builtin operators
+
+=back
+
+=item Utility Changes
+
+=over 4
+
+=item pod2html
+
+Sends converted HTML to standard output
+
+=item xsubpp
+
+C<void> XSUBs now default to returning nothing
+
+=back
+
+=item C Language API Changes
+
+C<gv_fetchmethod> and C<perl_call_sv>, C<perl_eval_pv>, Extended API for
+manipulating hashes
+
+=item Documentation Changes
+
+L<perldelta>, L<perlfaq>, L<perllocale>, L<perltoot>, L<perlapio>,
+L<perlmodlib>, L<perldebug>, L<perlsec>
+
+=item New Diagnostics
+
+"my" variable %s masks earlier declaration in same scope, %s argument is
+not a HASH element or slice, Allocation too large: %lx, Allocation too
+large, Applying %s to %s will act on scalar(%s), Attempt to free
+nonexistent shared string, Attempt to use reference as lvalue in substr,
+Bareword "%s" refers to nonexistent package, Can't redefine active sort
+subroutine %s, Can't use bareword ("%s") as %s ref while "strict refs" in
+use, Cannot resolve method `%s' overloading `%s' in package `%s', Constant
+subroutine %s redefined, Constant subroutine %s undefined, Copy method did
+not return a reference, Died, Exiting pseudo-block via %s, Identifier too
+long, Illegal character %s (carriage return), Illegal switch in PERL5OPT:
+%s, Integer overflow in hex number, Integer overflow in octal number,
+internal error: glob failed, Invalid conversion in %s: "%s", Invalid type
+in pack: '%s', Invalid type in unpack: '%s', Name "%s::%s" used only once:
+possible typo, Null picture in formline, Offset outside string, Out of
+memory!, Out of memory during request for %s, panic: frexp, Possible
+attempt to put comments in qw() list, Possible attempt to separate words
+with commas, Scalar value @%s{%s} better written as $%s{%s}, Stub found
+while resolving method `%s' overloading `%s' in %s, Too late for "B<-T>"
+option, untie attempted while %d inner references still exist, Unrecognized
+character %s, Unsupported function fork, Use of "$$<digit>" to mean
+"${$}<digit>" is deprecated, Value of %s can be "0"; test with defined(),
+Variable "%s" may be unavailable, Variable "%s" will not stay shared,
+Warning: something's wrong, Ill-formed logical name |%s| in prime_env_iter,
+Got an error from DosAllocMem, Malformed PERLLIB_PREFIX, PERL_SH_DIR too
+long, Process terminated by SIG%s
+
+=item BUGS
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 perlartistic - the Perl Artistic License
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item The "Artistic License"
+
+=over 4
+
+=item Preamble
+
+=item Definitions
+
+"Package", "Standard Version", "Copyright Holder", "You", "Reasonable
+copying fee", "Freely Available"
+
+=item Conditions
+
+a), b), c), d), a), b), c), d)
+
+=back
+
+=back
+
+=head2 perlgpl - the GNU General Public License, version 1
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item GNU GENERAL PUBLIC LICENSE
+
+=back
+
+=head2 perlaix, README.aix - Perl version 5 on IBM AIX (UNIX) systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Compiling Perl 5 on AIX
+
+=item Supported Compilers
+
+=item Incompatibility with AIX Toolbox lib gdbm
+
+=item Perl 5 was successfully compiled and tested on:
+
+=item Building Dynamic Extensions on AIX
+
+=item Using Large Files with Perl
+
+=item Threaded Perl
+
+=item 64-bit Perl
+
+=item Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (threaded/32-bit)
+
+=item Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (32-bit)
+
+=item Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (threaded/64-bit)
+
+=item Recommended Options AIX 5.1/5.2/5.3/6.1 and 7.1 (64-bit)
+
+=item Compiling Perl 5 on older AIX versions up to 4.3.3
+
+=item OS level
+
+=item Building Dynamic Extensions on AIX E<lt> 5L
+
+=item The IBM ANSI C Compiler
+
+=item The usenm option
+
+=item Using GNU's gcc for building Perl
+
+=item Using Large Files with Perl E<lt> 5L
+
+=item Threaded Perl E<lt> 5L
+
+=item 64-bit Perl E<lt> 5L
+
+=item AIX 4.2 and extensions using C++ with statics
+
+=back
+
+=item AUTHORS
+
+=item DATE
+
+=back
+
+=head2 perlamiga - Perl under Amiga OS
+
+=over 4
+
+=item NOTE
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Prerequisites for Compiling Perl on AmigaOS
+
+B<Unix emulation for AmigaOS: ixemul.library>, B<Version of Amiga OS>
+
+=item Starting Perl programs under AmigaOS
+
+=item Shortcomings of Perl under AmigaOS
+
+=back
+
+=item INSTALLATION
+
+=item Accessing documentation
+
+=over 4
+
+=item Manpages for Perl on AmigaOS
+
+=item Perl HTML Documentation on AmigaOS
+
+=item Perl GNU Info Files on AmigaOS
+
+=item Perl LaTeX Documentation on AmigaOS
+
+=back
+
+=item BUILDING PERL ON AMIGAOS
+
+=over 4
+
+=item Build Prerequisites for Perl on AmigaOS
+
+=item Getting the Perl Source for AmigaOS
+
+=item Making Perl on AmigaOS
+
+=item Testing Perl on AmigaOS
+
+=item Installing the built Perl on AmigaOS
+
+=back
+
+=item PERL 5.8.0 BROKEN IN AMIGAOS
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 perlapollo, README.apollo - Perl version 5 on Apollo DomainOS
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 perlbeos, README.beos - Perl version 5.8+ on BeOS
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUILD AND INSTALL
+
+=over 4
+
+=item Requirements
+
+=item Configure
+
+=item Build
+
+=item Install
+
+=back
+
+=item KNOWN PROBLEMS
+
+=item CONTACT
+
+=back
+
+=head2 perlbs2000, README.BS2000 - building and installing Perl for BS2000.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item gzip on BS2000
+
+=item bison on BS2000
+
+=item Unpacking Perl Distribution on BS2000
+
+=item Compiling Perl on BS2000
+
+=item Testing Perl on BS2000
+
+=item Installing Perl on BS2000
+
+=item Using Perl in the Posix-Shell of BS2000
+
+=item Using Perl in "native" BS2000
+
+=item Floating point anomalies on BS2000
+
+=item Using PerlIO and different encodings on ASCII and EBCDIC partitions
+
+=back
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=over 4
+
+=item Mailing list
+
+=back
+
+=item HISTORY
+
+=back
+
+=head2 perlce - Perl for WinCE
+
+=over 4
+
+=item Building Perl for WinCE
+
+=over 4
+
+=item DESCRIPTION
+
+=item General explanations on cross-compiling WinCE
+
+=item BUILD
+
+Microsoft Embedded Visual Tools, Microsoft Visual C++, Rainer Keuchel's
+celib-sources, Rainer Keuchel's console-sources, go to C<./win32>
+subdirectory, edit file C<./win32/ce-helpers/compile.bat>, run
+compile.bat, run compile.bat dist
+
+=back
+
+=item Using Perl on WinCE
+
+=over 4
+
+=item DESCRIPTION
+
+=item LIMITATIONS
+
+=item ENVIRONMENT
+
+PERL5LIB, PATH, TMP, UNIXROOTPATH, ROWS/COLS, HOME, CONSOLEFONTSIZE
+
+=item REGISTRY
+
+=item XS
+
+=item BUGS
+
+=item INSTALLATION
+
+=back
+
+=item ACKNOWLEDGEMENTS
+
+=item History of WinCE port
+
+=item AUTHORS
+
+Rainer Keuchel <coyxc@rainer-keuchel.de>, Vadim Konovalov
+
+=back
+
+=head2 perlcygwin, README.cygwin - Perl for Cygwin
+
+=over 4
+
+=item SYNOPSIS
+
+=item PREREQUISITES FOR COMPILING PERL ON CYGWIN
+
+=over 4
+
+=item Cygwin = GNU+Cygnus+Windows (Don't leave UNIX without it)
+
+=item Cygwin Configuration
+
+C<PATH>, I<nroff>, Permissions
+
+=back
+
+=item CONFIGURE PERL ON CYGWIN
+
+=over 4
+
+=item Stripping Perl Binaries on Cygwin
+
+=item Optional Libraries for Perl on Cygwin
+
+C<-lcrypt>, C<-lgdbm_compat> (C<use GDBM_File>), C<-ldb> (C<use DB_File>),
+C<cygserver> (C<use IPC::SysV>), C<-lutil>
+
+=item Configure-time Options for Perl on Cygwin
+
+C<-Uusedl>, C<-Uusemymalloc>, C<-Uuseperlio>, C<-Dusemultiplicity>,
+C<-Duse64bitint>, C<-Duselongdouble>, C<-Dusethreads>, C<-Duselargefiles>,
+C<-Dmksymlinks>
+
+=item Suspicious Warnings on Cygwin
+
+Win9x and C<d_eofnblk>, Compiler/Preprocessor defines
+
+=back
+
+=item MAKE ON CYGWIN
+
+=item TEST ON CYGWIN
+
+=over 4
+
+=item File Permissions on Cygwin
+
+=item NDBM_File and ODBM_File do not work on FAT filesystems
+
+=item C<fork()> failures in io_* tests
+
+=back
+
+=item Specific features of the Cygwin port
+
+=over 4
+
+=item Script Portability on Cygwin
+
+Pathnames, Text/Binary, PerlIO, F<.exe>, Cygwin vs. Windows process ids,
+Cygwin vs. Windows errors, C<chown()>, Miscellaneous
+
+=item Prebuilt methods:
+
+C<Cwd::cwd>, C<Cygwin::pid_to_winpid>, C<Cygwin::winpid_to_pid>,
+C<Cygwin::win_to_posix_path>, C<Cygwin::posix_to_win_path>,
+C<Cygwin::mount_table()>, C<Cygwin::mount_flags>, C<Cygwin::is_binmount>
+
+=back
+
+=item INSTALL PERL ON CYGWIN
+
+=item MANIFEST ON CYGWIN
+
+Documentation, Build, Configure, Make, Install, Tests, Compiled Perl
+Source, Compiled Module Source, Perl Modules/Scripts, Perl Module Tests
+
+=item BUGS ON CYGWIN
+
+=item AUTHORS
+
+=item HISTORY
+
+=back
+
+=head2 perldgux - Perl under DG/UX.
+
+=over 4
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUILDING PERL ON DG/UX
+
+=over 4
+
+=item Non-threaded Perl on DG/UX
+
+=item Threaded Perl on DG/UX
+
+=item Testing Perl on DG/UX
+
+=item Installing the built perl on DG/UX
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perldos - Perl under DOS, W31, W95.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Prerequisites for Compiling Perl on DOS
+
+DJGPP, Pthreads
+
+=item Shortcomings of Perl under DOS
+
+=item Building Perl on DOS
+
+=item Testing Perl on DOS
+
+=item Installation of Perl on DOS
+
+=back
+
+=item BUILDING AND INSTALLING MODULES ON DOS
+
+=over 4
+
+=item Building Prerequisites for Perl on DOS
+
+=item Unpacking CPAN Modules on DOS
+
+=item Building Non-XS Modules on DOS
+
+=item Building XS Modules on DOS
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlepoc, README.epoc - Perl for EPOC
+
+=over 4
+
+=item SYNOPSIS
+
+=item INTRODUCTION
+
+=item INSTALLING PERL ON EPOC
+
+=item STARTING PERL ON EPOC
+
+=over 4
+
+=item Features of Perl on Epoc
+
+=item Restrictions of Perl on Epoc
+
+=item Compiling Perl 5 on the EPOC cross compiling environment
+
+=back
+
+=item SUPPORT STATUS OF PERL ON EPOC
+
+=item AUTHOR
+
+=item LAST UPDATE
+
+=back
+
+=head2 perlfreebsd, README.freebsd - Perl version 5 on FreeBSD systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item FreeBSD core dumps from readdir_r with ithreads
+
+=item $^X doesn't always contain a full path in FreeBSD
+
+=item Perl will no longer be part of "base FreeBSD"
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlhaiku, README.haiku - Perl version 5.10+ on Haiku
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUILD AND INSTALL
+
+=item KNOWN PROBLEMS
+
+=item CONTACT
+
+=back
+
+=head2 perlhpux, README.hpux - Perl version 5 on Hewlett-Packard Unix
+(HP-UX) systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Using perl as shipped with HP-UX
+
+=item Using perl from HP's porting centre
+
+=item Compiling Perl 5 on HP-UX
+
+=item PA-RISC
+
+=item Portability Between PA-RISC Versions
+
+=item PA-RISC 1.0
+
+=item PA-RISC 1.1
+
+=item PA-RISC 2.0
+
+=item Itanium Processor Family (IPF) and HP-UX
+
+=item Itanium, Itanium 2 & Madison 6
+
+=item HP-UX versions
+
+=item Building Dynamic Extensions on HP-UX
+
+=item The HP ANSI C Compiler
+
+=item The GNU C Compiler
+
+=item Using Large Files with Perl on HP-UX
+
+=item Threaded Perl on HP-UX
+
+=item 64-bit Perl on HP-UX
+
+=item Oracle on HP-UX
+
+=item GDBM and Threads on HP-UX
+
+=item NFS filesystems and utime(2) on HP-UX
+
+=item HP-UX Kernel Parameters (maxdsiz) for Compiling Perl
+
+=back
+
+=item nss_delete core dump from op/pwent or op/grent
+
+=item Miscellaneous
+
+=item AUTHOR
+
+=item DATE
+
+=back
+
+=head2 perlhurd, README.hurd - Perl version 5 on Hurd
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Known Problems with Perl on Hurd
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlirix, README.irix - Perl version 5 on Irix systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Building 32-bit Perl in Irix
+
+=item Building 64-bit Perl in Irix
+
+=item About Compiler Versions of Irix
+
+=item Linker Problems in Irix
+
+=item Malloc in Irix
+
+=item Building with threads in Irix
+
+=item Irix 5.3
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perllinux, README.linux - Perl version 5 on Linux systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Experimental Support for Sun Studio Compilers for Linux OS
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlmacos, README.macos - Perl under Mac OS (Classic)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 perlmacosx, README.macosx - Perl under Mac OS X
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Installation Prefix
+
+=item SDK support
+
+=item Universal Binary support
+
+=item 64-bit PPC support
+
+=item libperl and Prebinding
+
+=item Updating Apple's Perl
+
+=item Known problems
+
+=item MacPerl
+
+=item Carbon
+
+=item Cocoa
+
+=back
+
+=item Starting From Scratch
+
+=item AUTHOR
+
+=item DATE
+
+=back
+
+=head2 perlmpeix, README.mpeix - Perl/iX for HP e3000 MPE
+
+=over 4
+
+=item SYNOPSIS
+
+=item NOTE
+
+=item What's New in Perl for MPE/iX
+
+=item Welcome to Perl/iX
+
+=item System Requirements for Perl/iX
+
+=item How to Obtain Perl/iX
+
+=item Perl/iX Distribution Contents Highlights
+
+README, INSTALL, LIBSHP3K, PERL, .cpan/, lib/, man/,
+public_html/feedback.cgi, src/perl-5.6.0-mpe
+
+=item How to Compile Perl/iX
+
+ 4, 6
+
+=item Getting Started with Perl/iX
+
+=item MPE/iX Implementation Considerations
+
+=item Known Perl/iX Bugs Under Investigation
+
+=item Perl/iX To-Do List
+
+=item Perl/iX Change History
+
+=item AUTHOR
+
+=back
+
+=head2 perlnetware - Perl for NetWare
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUILD
+
+=over 4
+
+=item Tools & SDK
+
+=item Setup
+
+SetNWBld.bat, Buildtype.bat
+
+=item Make
+
+=item Interpreter
+
+=item Extensions
+
+=back
+
+=item INSTALL
+
+=item BUILD NEW EXTENSIONS
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHORS
+
+=item DATE
+
+=back
+
+=head2 perlopenbsd, README.openbsd - Perl version 5 on OpenBSD systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item OpenBSD core dumps from getprotobyname_r and getservbyname_r with
+ithreads
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
+
+=over 4
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Target
+
+=item Other OSes
+
+=item Prerequisites
+
+EMX, RSX, HPFS, pdksh
+
+=item Starting Perl programs under OS/2 (and DOS and...)
+
+=item Starting OS/2 (and DOS) programs under Perl
+
+=back
+
+=item Frequently asked questions
+
+=over 4
+
+=item "It does not work"
+
+=item I cannot run external programs
+
+=item I cannot embed perl into my program, or use F<perl.dll> from my
+program.
+
+Is your program EMX-compiled with C<-Zmt -Zcrtdll>?, Did you use
+L<ExtUtils::Embed>?
+
+=item C<``> and pipe-C<open> do not work under DOS.
+
+=item Cannot start C<find.exe "pattern" file>
+
+=back
+
+=item INSTALLATION
+
+=over 4
+
+=item Automatic binary installation
+
+C<PERL_BADLANG>, C<PERL_BADFREE>, F<Config.pm>
+
+=item Manual binary installation
+
+Perl VIO and PM executables (dynamically linked), Perl_ VIO executable
+(statically linked), Executables for Perl utilities, Main Perl library,
+Additional Perl modules, Tools to compile Perl modules, Manpages for Perl
+and utilities, Manpages for Perl modules, Source for Perl documentation,
+Perl manual in F<.INF> format, Pdksh
+
+=item B<Warning>
+
+=back
+
+=item Accessing documentation
+
+=over 4
+
+=item OS/2 F<.INF> file
+
+=item Plain text
+
+=item Manpages
+
+=item HTML
+
+=item GNU C<info> files
+
+=item F<PDF> files
+
+=item C<LaTeX> docs
+
+=back
+
+=item BUILD
+
+=over 4
+
+=item The short story
+
+=item Prerequisites
+
+=item Getting perl source
+
+=item Application of the patches
+
+=item Hand-editing
+
+=item Making
+
+=item Testing
+
+A lot of C<bad free>, Process terminated by SIGTERM/SIGINT, F<op/fs.t>,
+F<op/stat.t>
+
+=item Installing the built perl
+
+=item C<a.out>-style build
+
+=back
+
+=item Building a binary distribution
+
+=item Building custom F<.EXE> files
+
+=over 4
+
+=item Making executables with a custom collection of statically loaded
+extensions
+
+=item Making executables with a custom search-paths
+
+=back
+
+=item Build FAQ
+
+=over 4
+
+=item Some C</> became C<\> in pdksh.
+
+=item C<'errno'> - unresolved external
+
+=item Problems with tr or sed
+
+=item Some problem (forget which ;-)
+
+=item Library ... not found
+
+=item Segfault in make
+
+=item op/sprintf test failure
+
+=back
+
+=item Specific (mis)features of OS/2 port
+
+=over 4
+
+=item C<setpriority>, C<getpriority>
+
+=item C<system()>
+
+=item C<extproc> on the first line
+
+=item Additional modules:
+
+=item Prebuilt methods:
+
+C<File::Copy::syscopy>, C<DynaLoader::mod2fname>, C<Cwd::current_drive()>,
+ C<Cwd::sys_chdir(name)>, C<Cwd::change_drive(name)>,
+C<Cwd::sys_is_absolute(name)>, C<Cwd::sys_is_rooted(name)>,
+C<Cwd::sys_is_relative(name)>, C<Cwd::sys_cwd(name)>,
+C<Cwd::sys_abspath(name, dir)>, C<Cwd::extLibpath([type])>,
+C<Cwd::extLibpath_set( path [, type ] )>,
+C<OS2::Error(do_harderror,do_exception)>, C<OS2::Errors2Drive(drive)>,
+OS2::SysInfo(), OS2::BootDrive(), C<OS2::MorphPM(serve)>,
+C<OS2::UnMorphPM(serve)>, C<OS2::Serve_Messages(force)>,
+C<OS2::Process_Messages(force [, cnt])>, C<OS2::_control87(new,mask)>,
+OS2::get_control87(), C<OS2::set_control87_em(new=MCW_EM,mask=MCW_EM)>,
+C<OS2::DLLname([how [, \&xsub]])>
+
+=item Prebuilt variables:
+
+$OS2::emx_rev, $OS2::emx_env, $OS2::os_ver, $OS2::is_aout, $OS2::can_fork,
+$OS2::nsyserror
+
+=item Misfeatures
+
+=item Modifications
+
+C<popen>, C<tmpnam>, C<tmpfile>, C<ctermid>, C<stat>, C<mkdir>, C<rmdir>,
+C<flock>
+
+=item Identifying DLLs
+
+=item Centralized management of resources
+
+C<HAB>, C<HMQ>, Treating errors reported by OS/2 API,
+C<CheckOSError(expr)>, C<CheckWinError(expr)>, C<SaveWinError(expr)>,
+C<SaveCroakWinError(expr,die,name1,name2)>, C<WinError_2_Perl_rc>,
+C<FillWinError>, C<FillOSError(rc)>, Loading DLLs and ordinals in DLLs
+
+=back
+
+=item Perl flavors
+
+=over 4
+
+=item F<perl.exe>
+
+=item F<perl_.exe>
+
+=item F<perl__.exe>
+
+=item F<perl___.exe>
+
+=item Why strange names?
+
+=item Why dynamic linking?
+
+=item Why chimera build?
+
+=back
+
+=item ENVIRONMENT
+
+=over 4
+
+=item C<PERLLIB_PREFIX>
+
+=item C<PERL_BADLANG>
+
+=item C<PERL_BADFREE>
+
+=item C<PERL_SH_DIR>
+
+=item C<USE_PERL_FLOCK>
+
+=item C<TMP> or C<TEMP>
+
+=back
+
+=item Evolution
+
+=over 4
+
+=item Text-mode filehandles
+
+=item Priorities
+
+=item DLL name mangling: pre 5.6.2
+
+=item DLL name mangling: 5.6.2 and beyond
+
+Global DLLs, specific DLLs, C<BEGINLIBPATH> and C<ENDLIBPATH>, F<.> from
+C<LIBPATH>
+
+=item DLL forwarder generation
+
+=item Threading
+
+=item Calls to external programs
+
+=item Memory allocation
+
+=item Threads
+
+C<COND_WAIT>, F<os2.c>
+
+=back
+
+=item BUGS
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 perlos390, README.os390 - building and installing Perl for OS/390
+and z/OS
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Tools
+
+=item Unpacking Perl distribution on OS/390
+
+=item Setup and utilities for Perl on OS/390
+
+=item Configure Perl on OS/390
+
+=item Build, Test, Install Perl on OS/390
+
+=item Build Anomalies with Perl on OS/390
+
+=item Testing Anomalies with Perl on OS/390
+
+=item Installation Anomalies with Perl on OS/390
+
+=item Usage Hints for Perl on OS/390
+
+=item Floating Point Anomalies with Perl on OS/390
+
+=item Modules and Extensions for Perl on OS/390
+
+=back
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=over 4
+
+=item Mailing list for Perl on OS/390
+
+=back
+
+=item HISTORY
+
+=back
+
+=head2 perlos400, README.os400 - Perl version 5 on OS/400
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Compiling Perl for OS/400 PASE
+
+=item Installing Perl in OS/400 PASE
+
+=item Using Perl in OS/400 PASE
+
+=item Known Problems
+
+=item Perl on ILE
+
+=back
+
+=item AUTHORS
+
+=back
+
+=head2 perlplan9 - Plan 9-specific documentation for Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Invoking Perl
+
+=item What's in Plan 9 Perl
+
+=item What's not in Plan 9 Perl
+
+=item Perl5 Functions not currently supported in Plan 9 Perl
+
+=item Signals in Plan 9 Perl
+
+=back
+
+=item COMPILING AND INSTALLING PERL ON PLAN 9
+
+=over 4
+
+=item Installing Perl Documentation on Plan 9
+
+=back
+
+=item BUGS
+
+=item Revision date
+
+=item AUTHOR
+
+=back
+
+=head2 perlqnx, README.qnx - Perl version 5 on QNX
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Required Software for Compiling Perl on QNX4
+
+/bin/sh, ar, nm, cpp, make
+
+=item Outstanding Issues with Perl on QNX4
+
+=item QNX auxiliary files
+
+qnx/ar, qnx/cpp
+
+=item Outstanding issues with perl under QNX6
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 perlriscos, README.riscos - Perl version 5 for RISC OS
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUILD
+
+=item AUTHOR
+
+=back
+
+=head2 perlsolaris, README.solaris - Perl version 5 on Solaris systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Solaris Version Numbers.
+
+=back
+
+=item RESOURCES
+
+Solaris FAQ, Precompiled Binaries, Solaris Documentation
+
+=item SETTING UP
+
+=over 4
+
+=item File Extraction Problems on Solaris.
+
+=item Compiler and Related Tools on Solaris.
+
+=item Environment for Compiling perl on Solaris
+
+=back
+
+=item RUN CONFIGURE.
+
+=over 4
+
+=item 64-bit perl on Solaris.
+
+=item Threads in perl on Solaris.
+
+=item Malloc Issues with perl on Solaris.
+
+=back
+
+=item MAKE PROBLEMS.
+
+Dynamic Loading Problems With GNU as and GNU ld, ld.so.1: ./perl: fatal:
+relocation error:, dlopen: stub interception failed, #error "No
+DATAMODEL_NATIVE specified", sh: ar: not found
+
+=item MAKE TEST
+
+=over 4
+
+=item op/stat.t test 4 in Solaris
+
+=item nss_delete core dump from op/pwent or op/grent
+
+=back
+
+=item PREBUILT BINARIES OF PERL FOR SOLARIS.
+
+=item RUNTIME ISSUES FOR PERL ON SOLARIS.
+
+=over 4
+
+=item Limits on Numbers of Open Files on Solaris.
+
+=back
+
+=item SOLARIS-SPECIFIC MODULES.
+
+=item SOLARIS-SPECIFIC PROBLEMS WITH MODULES.
+
+=over 4
+
+=item Proc::ProcessTable on Solaris
+
+=item BSD::Resource on Solaris
+
+=item Net::SSLeay on Solaris
+
+=back
+
+=item SunOS 4.x
+
+=item AUTHOR
+
+=back
+
+=head2 perlsymbian, README.symbian - Perl version 5 on Symbian OS
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Compiling Perl on Symbian
+
+=item Compilation problems
+
+=item PerlApp
+
+=item sisify.pl
+
+=item Using Perl in Symbian
+
+=back
+
+=item TO DO
+
+=item WARNING
+
+=item NOTE
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item LICENSE
+
+=item HISTORY
+
+=back
+
+=head2 perltru64, README.tru64 - Perl version 5 on Tru64 (formerly known as
+Digital UNIX formerly known as DEC OSF/1) systems
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Compiling Perl 5 on Tru64
+
+=item Using Large Files with Perl on Tru64
+
+=item Threaded Perl on Tru64
+
+=item Long Doubles on Tru64
+
+=item DB_File tests failing on Tru64
+
+=item 64-bit Perl on Tru64
+
+=item Warnings about floating-point overflow when compiling Perl on Tru64
+
+=back
+
+=item Testing Perl on Tru64
+
+=item ext/ODBM_File/odbm Test Failing With Static Builds
+
+=item Perl Fails Because Of Unresolved Symbol sockatmark
+
+=item AUTHOR
+
+=back
+
+=head2 perluts - Perl under UTS
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUILDING PERL ON UTS
+
+=item Installing the built perl on UTS
+
+=item AUTHOR
+
+=back
+
+=head2 perlvmesa, README.vmesa - building and installing Perl for VM/ESA.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Unpacking Perl Distribution on VM/ESA
+
+=item Setup Perl and utilities on VM/ESA
+
+=item Configure Perl on VM/ESA
+
+=item Testing Anomalies of Perl on VM/ESA
+
+=item Usage Hints for Perl on VM/ESA
+
+=back
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=over 4
+
+=item Mailing list for Perl on VM/ESA
+
+=back
+
+=back
+
+=head2 perlvms - VMS-specific documentation for Perl
+
+=over 4
+
+=item DESCRIPTION
+
+=item Installation
+
+=item Organization of Perl Images
+
+=over 4
+
+=item Core Images
+
+=item Perl Extensions
+
+=item Installing static extensions
+
+=item Installing dynamic extensions
+
+=back
+
+=item File specifications
+
+=over 4
+
+=item Syntax
+
+=item Filename Case
+
+=item Symbolic Links
+
+=item Wildcard expansion
+
+=item Pipes
+
+=back
+
+=item PERL5LIB and PERLLIB
+
+=item The Perl Forked Debugger
+
+=item PERL_VMS_EXCEPTION_DEBUG
+
+=item Command line
+
+=over 4
+
+=item I/O redirection and backgrounding
+
+=item Command line switches
+
+-i, -S, -u
+
+=back
+
+=item Perl functions
+
+File tests, backticks, binmode FILEHANDLE, crypt PLAINTEXT, USER, die,
+dump, exec LIST, fork, getpwent, getpwnam, getpwuid, gmtime, kill, qx//,
+select (system call), stat EXPR, system LIST, time, times, unlink LIST,
+utime LIST, waitpid PID,FLAGS
+
+=item Perl variables
+
+%ENV, CRTL_ENV, CLISYM_[LOCAL], Any other string, $!, $^E, $?, $|
+
+=item Standard modules with VMS-specific differences
+
+=over 4
+
+=item SDBM_File
+
+=back
+
+=item Revision date
+
+=item AUTHOR
+
+=back
+
+=head2 perlvos, README.vos - Perl for Stratus VOS
+
+=over 4
+
+=item SYNOPSIS
+
+=item BUILDING PERL FOR VOS
+
+=item INSTALLING PERL IN VOS
+
+=item USING PERL IN VOS
+
+=over 4
+
+=item Restrictions of Perl on VOS
+
+=item Handling of underflow and overflow
+
+=back
+
+=item TEST STATUS
+
+=item SUPPORT STATUS
+
+=item AUTHOR
+
+=item LAST UPDATE
+
+=back
+
+=head2 perlwin32 - Perl under Windows
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Setting Up Perl on Win32
+
+Make, Command Shell, Borland C++, Microsoft Visual C++, Microsoft Visual
+C++ 2008 Express Edition, Microsoft Visual C++ 2005 Express Edition,
+Microsoft Visual C++ Toolkit 2003, Microsoft Platform SDK 64-bit Compiler,
+MinGW release 3 with gcc, MinGW release 1 with gcc
+
+=item Building
+
+=item Testing Perl on Win32
+
+=item Installation of Perl on Win32
+
+=item Usage Hints for Perl on Win32
+
+Environment Variables, File Globbing, Using perl from the command line,
+Building Extensions, Command-line Wildcard Expansion, Win32 Specific
+Extensions, Notes on 64-bit Windows
+
+=item Running Perl Scripts
+
+=item Miscellaneous Things
+
+=back
+
+=item BUGS AND CAVEATS
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHORS
+
+Gary Ng E<lt>71564.1743@CompuServe.COME<gt>, Gurusamy Sarathy
+E<lt>gsar@activestate.comE<gt>, Nick Ing-Simmons
+E<lt>nick@ing-simmons.netE<gt>, Jan Dubois E<lt>jand@activestate.comE<gt>,
+Steve Hay E<lt>steve.hay@uk.radan.comE<gt>
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head1 PRAGMA DOCUMENTATION
+
+=head2 attributes - get/set subroutine or variable attributes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item What C<import> does
+
+=item Built-in Attributes
+
+lvalue, method, locked
+
+=item Available Subroutines
+
+get, reftype
+
+=item Package-specific Attribute Handling
+
+FETCH_I<type>_ATTRIBUTES, MODIFY_I<type>_ATTRIBUTES
+
+=item Syntax of Attribute Lists
+
+=back
+
+=item EXPORTS
+
+=over 4
+
+=item Default exports
+
+=item Available exports
+
+=item Export tags defined
+
+=back
+
+=item EXAMPLES
+
+=item MORE EXAMPLES
+
+=item SEE ALSO
+
+=back
+
+=head2 autouse::lib::autouse, autouse - postpone load of modules until a
+function is used
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item WARNING
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 mro - Method Resolution Order
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OVERVIEW
+
+=item The C3 MRO
+
+=over 4
+
+=item What is C3?
+
+=item How does C3 work
+
+=back
+
+=item Functions
+
+=over 4
+
+=item mro::get_linear_isa($classname[, $type])
+
+=item mro::set_mro ($classname, $type)
+
+=item mro::get_mro($classname)
+
+=item mro::get_isarev($classname)
+
+=item mro::is_universal($classname)
+
+=item mro::invalidate_all_method_caches()
+
+=item mro::method_changed_in($classname)
+
+=item mro::get_pkg_gen($classname)
+
+=item next::method
+
+=item next::can
+
+=item maybe::next::method
+
+=back
+
+=item SEE ALSO
+
+=over 4
+
+=item The original Dylan paper
+
+L<http://www.webcom.com/haahr/dylan/linearization-oopsla96.html>
+
+=item Pugs
+
+=item Parrot
+
+L<http://aspn.activestate.com/ASPN/Mail/Message/perl6-internals/2746631>,
+L<http://use.perl.org/~autrijus/journal/25768>
+
+=item Python 2.3 MRO related links
+
+L<http://www.python.org/2.3/mro.html>,
+L<http://www.python.org/2.2.2/descrintro.html#mro>
+
+=item C3 for TinyCLOS
+
+L<http://www.call-with-current-continuation.org/eggs/c3.html>
+
+=item Class::C3
+
+L<Class::C3>
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 re - Perl pragma to alter regular expression behaviour
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item 'taint' mode
+
+=item 'eval' mode
+
+=item 'debug' mode
+
+=item 'Debug' mode
+
+Compile related options, COMPILE, PARSE, OPTIMISE, TRIEC, DUMP, Execute
+related options, EXECUTE, MATCH, TRIEE, INTUIT, Extra debugging options,
+EXTRA, BUFFERS, TRIEM, STATE, STACK, OPTIMISEM, OFFSETS, OFFSETSDBG, Other
+useful flags, ALL, All, MORE, More
+
+=item Exportable Functions
+
+is_regexp($ref), regexp_pattern($ref), regmust($ref), regname($name,$all),
+regnames($all), regnames_count()
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 autodie - Replace functions with ones that succeed or die with
+lexical scope
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXCEPTIONS
+
+=item CATEGORIES
+
+=item FUNCTION SPECIFIC NOTES
+
+=over 4
+
+=item flock
+
+=item system/exec
+
+=back
+
+=item GOTCHAS
+
+=item DIAGNOSTICS
+
+:void cannot be used with lexical scope, No user hints defined for %s
+
+=item BUGS
+
+=over 4
+
+=item autodie and string eval
+
+=item REPORTING BUGS
+
+=back
+
+=item FEEDBACK
+
+=item AUTHOR
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item ACKNOWLEDGEMENTS
+
+=back
+
+=head2 autodiexception, autodie::exception - Exceptions from autodying
+functions.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Common Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Advanced methods
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item LICENSE
+
+=item AUTHOR
+
+=back
+
+=head2 autodiexception::system, autodie::exception::system - Exceptions
+from autodying system().
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item stringify
+
+=back
+
+=over 4
+
+=item LICENSE
+
+=item AUTHOR
+
+=back
+
+=head2 autodie::hints - Provide hints about user subroutines to autodie
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Introduction
+
+=item What are hints?
+
+=item Example hints
+
+=back
+
+=item Manually setting hints from within your program
+
+=item Adding hints to your module
+
+=item Insisting on hints
+
+=back
+
+=over 4
+
+=item Diagnostics
+
+Attempts to set_hints_for unidentifiable subroutine, fail hints cannot be
+provided with either scalar or list hints for %s, %s hint missing for %s
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHOR
+
+=item LICENSE
+
+=item SEE ALSO
+
+=back
+
+=head2 autouse - postpone load of modules until a function is used
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item WARNING
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 base - Establish an ISA relationship with base classes at compile
+time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item DIAGNOSTICS
+
+Base class package "%s" is empty, Class 'Foo' tried to inherit from itself
+
+=item HISTORY
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=back
+
+=head2 bigint - Transparent BigInteger support for Perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item use integer vs. use bigint
+
+=item Options
+
+a or accuracy, p or precision, t or trace, hex, oct, l, lib, try or only, v
+or version
+
+=item Math Library
+
+=item Internal Format
+
+=item Sign
+
+=item Methods
+
+inf(), NaN(), e, PI, bexp(), bpi(), upgrade(), in_effect()
+
+=item MATH LIBRARY
+
+=item Caveat
+
+=back
+
+=item CAVAETS
+
+in_effect(), hex()/oct()
+
+=item MODULES USED
+
+=item EXAMPLES
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 bignum - Transparent BigNumber support for Perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Options
+
+a or accuracy, p or precision, t or trace, l or lib, hex, oct, v or version
+
+=item Methods
+
+=item Caveats
+
+inf(), NaN(), e, PI(), bexp(), bpi(), upgrade(), in_effect()
+
+=item Math Library
+
+=item INTERNAL FORMAT
+
+=item SIGN
+
+=back
+
+=item CAVAETS
+
+in_effect(), hex()/oct()
+
+=item MODULES USED
+
+=item EXAMPLES
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 bigrat - Transparent BigNumber/BigRational support for Perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Modules Used
+
+=item Math Library
+
+=item Sign
+
+=item Methods
+
+inf(), NaN(), e, PI, bexp(), bpi(), upgrade(), in_effect()
+
+=item MATH LIBRARY
+
+=item Cavaet
+
+=item Options
+
+a or accuracy, p or precision, t or trace, l or lib, hex, oct, v or version
+
+=back
+
+=item CAVAETS
+
+in_effect(), hex()/oct()
+
+=item EXAMPLES
+
+ perl -Mbigrat -le 'print sqrt(33)'
+ perl -Mbigrat -le 'print 2*255'
+ perl -Mbigrat -le 'print 4.5+2*255'
+ perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
+ perl -Mbigrat -le 'print 12->is_odd()';
+ perl -Mbignum=l,GMP -le 'print 7 ** 7777'
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 blib - Use MakeMaker's uninstalled version of a package
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 bytes - Perl pragma to force byte semantics rather than character
+semantics
+
+=over 4
+
+=item NOTICE
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item LIMITATIONS
+
+=item SEE ALSO
+
+=back
+
+=head2 charnames - define character names for C<\N{named}> string literal
+escapes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ALIASES
+
+=item CUSTOM ALIASES
+
+=over 4
+
+=item Anonymous hashes
+
+=item Alias file
+
+=item Alias shortcut
+
+=back
+
+=item charnames::viacode(code)
+
+=item charnames::vianame(name)
+
+=item CUSTOM TRANSLATORS
+
+=item ILLEGAL CHARACTERS
+
+=item BUGS
+
+=back
+
+=head2 constant - Perl pragma to declare constants
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=over 4
+
+=item List constants
+
+=item Defining multiple constants at once
+
+=item Magic constants
+
+=back
+
+=item TECHNICAL NOTES
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item BUGS
+
+=item AUTHORS
+
+=item COPYRIGHT & LICENSE
+
+=back
+
+=head2 deprecate - Perl pragma for deprecating the core version of a module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item EXPORT
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 diagnostics, splain - produce verbose warning diagnostics
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item The C<diagnostics> Pragma
+
+=item The I<splain> Program
+
+=back
+
+=item EXAMPLES
+
+=item INTERNALS
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 encoding - allows you to write your script in non-ascii or non-utf8
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=over 4
+
+=item Literal Conversions
+
+=item PerlIO layers for C<STD(IN|OUT)>
+
+=item Implicit upgrading for byte strings
+
+=item Side effects
+
+=back
+
+=item FEATURES THAT REQUIRE 5.8.1
+
+"NON-EUC" doublebyte encodings, tr//, DATA pseudo-filehandle
+
+=item USAGE
+
+use encoding [I<ENCNAME>] ;, use encoding I<ENCNAME> [ STDIN =E<gt>
+I<ENCNAME_IN> ...] ;, use encoding I<ENCNAME> Filter=E<gt>1;, no encoding;
+
+=item The Filter Option
+
+=over 4
+
+=item Filter-related changes at Encode version 1.87
+
+=back
+
+=item CAVEATS
+
+=over 4
+
+=item NOT SCOPED
+
+=item DO NOT MIX MULTIPLE ENCODINGS
+
+=item tr/// with ranges
+
+Legend of characters above
+
+=back
+
+=item EXAMPLE - Greekperl
+
+=item KNOWN PROBLEMS
+
+literals in regex that are longer than 127 bytes, EBCDIC, format, Thread
+safety
+
+=over 4
+
+=item The Logic of :locale
+
+=back
+
+=item HISTORY
+
+=item SEE ALSO
+
+=back
+
+=head2 encoding::warnings - Warn on implicit encoding conversions
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overview of the problem
+
+=item Detecting the problem
+
+=item Solving the problem
+
+Upgrade both sides to unicode-strings, Downgrade both sides to
+byte-strings, Specify the encoding for implicit byte-string upgrading,
+PerlIO layers for B<STDIN> and B<STDOUT>, Literal conversions, Implicit
+upgrading for byte-strings
+
+=back
+
+=item CAVEATS
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 feature - Perl pragma to enable new features
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Lexical effect
+
+=item C<no feature>
+
+=item The 'switch' feature
+
+=item The 'say' feature
+
+=item the 'state' feature
+
+=item the 'unicode_strings' feature
+
+=back
+
+=item FEATURE BUNDLES
+
+=item IMPLICIT LOADING
+
+=back
+
+=head2 fields - compile-time class fields
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+new, phash
+
+=item SEE ALSO
+
+=back
+
+=head2 filetest - Perl pragma to control the filetest permission operators
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Consider this carefully
+
+=item The "access" sub-pragma
+
+=item Limitation with regard to C<_>
+
+=back
+
+=back
+
+=head2 if - C<use> a Perl module if a condition holds
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 inc::latest - use modules bundled in inc/ if they are newer than
+installed ones
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Special notes on bundling
+
+=back
+
+=item USAGE
+
+=over 4
+
+=item Author-mode
+
+loaded_modules(), write(), bundle_module()
+
+=item As bundled in inc/
+
+=back
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 integer - Perl pragma to use integer arithmetic instead of floating
+point
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 less - perl pragma to request less of something
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FOR MODULE AUTHORS
+
+=over 4
+
+=item C<< BOOLEAN = less->of( FEATURE ) >>
+
+=item C<< FEATURES = less->of() >>
+
+=back
+
+=item CAVEATS
+
+This probably does nothing, This works only on 5.10+
+
+=back
+
+=head2 lib - manipulate @INC at compile time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Adding directories to @INC
+
+=item Deleting directories from @INC
+
+=item Restoring original @INC
+
+=back
+
+=item CAVEATS
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 locale - Perl pragma to use and avoid POSIX locales for built-in
+operations
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 open - perl pragma to set default PerlIO layers for input and output
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NONPERLIO FUNCTIONALITY
+
+=item IMPLEMENTATION DETAILS
+
+=item SEE ALSO
+
+=back
+
+=head2 ops - Perl pragma to restrict unsafe operations when compiling
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 overload - Package for overloading Perl operations
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Declaration of overloaded functions
+
+=item Calling Conventions for Binary Operations
+
+FALSE, TRUE, C<undef>
+
+=item Calling Conventions for Unary Operations
+
+=item Calling Conventions for Mutators
+
+C<++> and C<-->, C<x=> and other assignment versions
+
+=item Overloadable Operations
+
+I<Arithmetic operations>, I<Comparison operations>, I<Bit operations>,
+I<Increment and decrement>, I<Transcendental functions>, I<Boolean, string,
+numeric and regexp conversions>, I<Iteration>, I<File tests>, I<Matching>,
+I<Dereferencing>, I<Special>
+
+=item Inheritance and overloading
+
+Strings as values of C<use overload> directive, Overloading of an operation
+is inherited by derived classes
+
+=back
+
+=item SPECIAL SYMBOLS FOR C<use overload>
+
+=over 4
+
+=item Last Resort
+
+=item Fallback
+
+C<undef>, TRUE, defined, but FALSE
+
+=item Copy Constructor
+
+B<Example>
+
+=back
+
+=item MAGIC AUTOGENERATION
+
+I<Assignment forms of arithmetic operations>, I<Conversion operations>,
+I<Increment and decrement>, C<abs($a)>, I<Unary minus>, I<Negation>,
+I<Concatenation>, I<Comparison operations>, I<Iterator>, I<Dereferencing>,
+I<Copy operator>
+
+=item Minimal set of overloaded operations
+
+=item Losing overloading
+
+=item Run-time Overloading
+
+=item Public functions
+
+overload::StrVal(arg), overload::Overloaded(arg), overload::Method(obj,op)
+
+=item Overloading constants
+
+integer, float, binary, q, qr
+
+=item IMPLEMENTATION
+
+=item Metaphor clash
+
+=item Cookbook
+
+=over 4
+
+=item Two-face scalars
+
+=item Two-face references
+
+=item Symbolic calculator
+
+=item I<Really> symbolic calculator
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item DIAGNOSTICS
+
+Odd number of arguments for overload::constant, `%s' is not an overloadable
+type, `%s' is not a code reference
+
+=item BUGS
+
+=back
+
+=head2 overloading - perl pragma to lexically control overloading
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<no overloading>, C<no overloading @ops>, C<use overloading>, C<use
+overloading @ops>
+
+=back
+
+=head2 parent - Establish an ISA relationship with base classes at compile
+time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item DIAGNOSTICS
+
+Class 'Foo' tried to inherit from itself
+
+=item HISTORY
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item AUTHORS AND CONTRIBUTORS
+
+=item MAINTAINER
+
+=item LICENSE
+
+=back
+
+=head2 sigtrap - Perl pragma to enable simple signal handling
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+=over 4
+
+=item SIGNAL HANDLERS
+
+B<stack-trace>, B<die>, B<handler> I<your-handler>
+
+=item SIGNAL LISTS
+
+B<normal-signals>, B<error-signals>, B<old-interface-signals>
+
+=item OTHER
+
+B<untrapped>, B<any>, I<signal>, I<number>
+
+=back
+
+=item EXAMPLES
+
+=back
+
+=head2 sort - perl pragma to control sort() behaviour
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEATS
+
+=back
+
+=head2 strict - Perl pragma to restrict unsafe constructs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<strict refs>, C<strict vars>, C<strict subs>
+
+=item HISTORY
+
+=back
+
+=head2 subs - Perl pragma to predeclare sub names
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 threads - Perl interpreter-based threads
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$thr = threads->create(FUNCTION, ARGS), $thr->join(), $thr->detach(),
+threads->detach(), threads->self(), $thr->tid(), threads->tid(), "$thr",
+threads->object($tid), threads->yield(), threads->list(),
+threads->list(threads::all), threads->list(threads::running),
+threads->list(threads::joinable), $thr1->equal($thr2), async BLOCK;,
+$thr->error(), $thr->_handle(), threads->_handle()
+
+=item EXITING A THREAD
+
+threads->exit(), threads->exit(status), die(), exit(status), use threads
+'exit' => 'threads_only', threads->create({'exit' => 'thread_only'}, ...),
+$thr->set_thread_exit_only(boolean), threads->set_thread_exit_only(boolean)
+
+=item THREAD STATE
+
+$thr->is_running(), $thr->is_joinable(), $thr->is_detached(),
+threads->is_detached()
+
+=item THREAD CONTEXT
+
+=over 4
+
+=item Explicit context
+
+=item Implicit context
+
+=item $thr->wantarray()
+
+=item threads->wantarray()
+
+=back
+
+=item THREAD STACK SIZE
+
+threads->get_stack_size();, $size = $thr->get_stack_size();, $old_size =
+threads->set_stack_size($new_size);, use threads ('stack_size' => VALUE);,
+$ENV{'PERL5_ITHREADS_STACK_SIZE'}, threads->create({'stack_size' => VALUE},
+FUNCTION, ARGS), $thr2 = $thr1->create(FUNCTION, ARGS)
+
+=item THREAD SIGNALLING
+
+$thr->kill('SIG...');
+
+=item WARNINGS
+
+Perl exited with active threads:, Thread creation failed: pthread_create
+returned #, Thread # terminated abnormally: .., Using minimum thread stack
+size of #, Thread creation failed: pthread_attr_setstacksize(I<SIZE>)
+returned 22
+
+=item ERRORS
+
+This Perl not built to support threads, Cannot change stack size of an
+existing thread, Cannot signal threads without safe signals, Unrecognized
+signal name: ..
+
+=item BUGS AND LIMITATIONS
+
+Thread-safe modules, Using non-thread-safe modules, Current working
+directory, Environment variables, Parent-child threads, Creating threads
+inside special blocks, Unsafe signals, Perl has been built with
+C<PERL_OLD_SIGNALS> (see C<perl -V>), The environment variable
+C<PERL_SIGNALS> is set to C<unsafe> (see L<perlrun/"PERL_SIGNALS">), The
+module L<Perl::Unsafe::Signals> is used, Returning closures from threads,
+Returning objects from threads, END blocks in threads, Perl Bugs and the
+CPAN Version of L<threads>
+
+=item REQUIREMENTS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item LICENSE
+
+=item ACKNOWLEDGEMENTS
+
+=back
+
+=head2 threadshared, threads::shared - Perl extension for sharing data
+structures between threads
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXPORT
+
+=item FUNCTIONS
+
+share VARIABLE, shared_clone REF, is_shared VARIABLE, lock VARIABLE,
+cond_wait VARIABLE, cond_wait CONDVAR, LOCKVAR, cond_timedwait VARIABLE,
+ABS_TIMEOUT, cond_timedwait CONDVAR, ABS_TIMEOUT, LOCKVAR, cond_signal
+VARIABLE, cond_broadcast VARIABLE
+
+=item OBJECTS
+
+=item NOTES
+
+=item BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source
+code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Utility functions
+
+$num_octets = utf8::upgrade($string), $success = utf8::downgrade($string[,
+FAIL_OK]), utf8::encode($string), $success = utf8::decode($string), $flag =
+utf8::is_utf8(STRING), $flag = utf8::valid(STRING)
+
+=back
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 vars - Perl pragma to predeclare global variable names (obsolete)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 version - Perl extension for Version Objects
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item TYPES OF VERSION OBJECTS
+
+Decimal Versions, Dotted Decimal Versions
+
+=item DECLARING VERSIONS
+
+=over 4
+
+=item How to convert a module from decimal to dotted-decimal
+
+=item How to C<declare()> a dotted-decimal version
+
+=back
+
+=item PARSING AND COMPARING VERSIONS
+
+=over 4
+
+=item How to C<parse()> a version
+
+=item How to check for a legal version string
+
+C<is_lax()>, C<is_strict()>
+
+=item How to compare version objects
+
+=back
+
+=item OBJECT METHODS
+
+=over 4
+
+=item is_alpha()
+
+=item is_qv()
+
+=item normal()
+
+=item numify()
+
+=item stringify()
+
+=back
+
+=item EXPORTED FUNCTIONS
+
+=over 4
+
+=item qv()
+
+=item is_lax()
+
+=item is_strict()
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 version::Internals - Perl extension for Version Objects
+
+=over 4
+
+=item DESCRIPTION
+
+=item WHAT IS A VERSION?
+
+Decimal Versions, Dotted-Decimal Versions
+
+=over 4
+
+=item Decimal Versions
+
+=item Dotted-Decimal Versions
+
+=item Alpha Versions
+
+=item Regular Expressions for Version Parsing
+
+C<$version::LAX>, C<$version::STRICT>, v1.234.5
+
+=back
+
+=item IMPLEMENTATION DETAILS
+
+=over 4
+
+=item Equivalence between Decimal and Dotted-Decimal Versions
+
+=item Quoting Rules
+
+=item What about v-strings?
+
+=item Version Object Internals
+
+original, qv, alpha, version
+
+=item Replacement UNIVERSAL::VERSION
+
+=back
+
+=item USAGE DETAILS
+
+=over 4
+
+=item Using modules that use version.pm
+
+Decimal versions always work, Dotted-Decimal version work sometimes
+
+=item Object Methods
+
+new(), qv(), Normal Form, Numification, Stringification, Comparison
+operators, Logical Operators
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 vmsish - Perl pragma to control VMS-specific language features
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<vmsish status>, C<vmsish exit>, C<vmsish time>, C<vmsish hushed>
+
+=back
+
+=head2 warnings - Perl pragma to control optional warnings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+use warnings::register, warnings::enabled(), warnings::enabled($category),
+warnings::enabled($object), warnings::fatal_enabled(),
+warnings::fatal_enabled($category), warnings::fatal_enabled($object),
+warnings::warn($message), warnings::warn($category, $message),
+warnings::warn($object, $message), warnings::warnif($message),
+warnings::warnif($category, $message), warnings::warnif($object, $message)
+
+=back
+
+=head2 warnings::register - warnings import function
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head1 MODULE DOCUMENTATION
+
+=head2 AnyDBM_File - provide framework for multiple DBMs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item DBM Comparisons
+
+[0], [1], [2], [3]
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 App::Cpan - easily interact with CPAN from the command line
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Options
+
+-a, -A module [ module ... ], -c module, -C module [ module ... ], -D
+module [ module ... ], -f, -F, -g module [ module ... ], -G module [ module
+... ], -h, -i, -j Config.pm, -J, -l, -L author [ author ... ], -m, -O, -t,
+-r, -u, -v
+
+=item Examples
+
+=item Methods
+
+=back
+
+=back
+
+run()
+
+=over 4
+
+=item EXIT VALUES
+
+=item TO DO
+
+=item BUGS
+
+=item SEE ALSO
+
+=item SOURCE AVAILABILITY
+
+=item CREDITS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 App::Prove - Implements the C<prove> command.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Attributes
+
+C<archive>, C<argv>, C<backwards>, C<blib>, C<color>, C<directives>,
+C<dry>, C<exec>, C<extension>, C<failures>, C<comments>, C<formatter>,
+C<harness>, C<ignore_exit>, C<includes>, C<jobs>, C<lib>, C<merge>,
+C<modules>, C<parse>, C<plugins>, C<quiet>, C<really_quiet>, C<recurse>,
+C<rules>, C<show_count>, C<show_help>, C<show_man>, C<show_version>,
+C<shuffle>, C<state>, C<state_class>, C<taint_fail>, C<taint_warn>,
+C<test_args>, C<timer>, C<verbose>, C<warnings_fail>, C<warnings_warn>
+
+=back
+
+=over 4
+
+=item PLUGINS
+
+=over 4
+
+=item Sample Plugin
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 App::Prove::State - State storage for the C<prove> command.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+C<store>, C<extension> (optional), C<result_class> (optional)
+
+=back
+
+=back
+
+=over 4
+
+=item C<result_class>
+
+=back
+
+=over 4
+
+=item C<extension>
+
+=back
+
+=over 4
+
+=item C<results>
+
+=back
+
+=over 4
+
+=item C<commit>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+C<last>, C<failed>, C<passed>, C<all>, C<hot>, C<todo>, C<slow>, C<fast>,
+C<new>, C<old>, C<save>
+
+=back
+
+=head2 App::Prove::State::Result - Individual test suite results.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item C<state_version>
+
+=back
+
+=over 4
+
+=item C<test_class>
+
+=back
+
+=head2 App::Prove::State::Result::Test - Individual test results.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 Archive::Extract - A generic archive extracting mechanism
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $ae = Archive::Extract->new(archive => '/path/to/archive',[type =>
+TYPE])
+
+tar, tgz, gz, Z, zip, bz2, tbz, lzma
+
+=back
+
+=back
+
+=over 4
+
+=item $ae->extract( [to => '/output/path'] )
+
+$ae->extract_path, $ae->files
+
+=back
+
+=over 4
+
+=item ACCESSORS
+
+=over 4
+
+=item $ae->error([BOOL])
+
+=item $ae->extract_path
+
+=item $ae->files
+
+=item $ae->archive
+
+=item $ae->type
+
+=item $ae->types
+
+=back
+
+=back
+
+=over 4
+
+=item $ae->is_tgz
+
+=item $ae->is_tar
+
+=item $ae->is_gz
+
+=item $ae->is_Z
+
+=item $ae->is_zip
+
+=item $ae->is_lzma
+
+=back
+
+=over 4
+
+=item $ae->bin_tar
+
+=item $ae->bin_gzip
+
+=item $ae->bin_unzip
+
+=item $ae->bin_unlzma
+
+=back
+
+=over 4
+
+=item $bool = $ae->have_old_bunzip2
+
+=back
+
+=over 4
+
+=item HOW IT WORKS
+
+=item CAVEATS
+
+=over 4
+
+=item File Extensions
+
+=item Supporting Very Large Files
+
+=item Bunzip2 support of arbitrary extensions.
+
+=back
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Archive::Extract::DEBUG
+
+=item $Archive::Extract::WARN
+
+=item $Archive::Extract::PREFER_BIN
+
+=back
+
+=item TODO / CAVEATS
+
+Mime magic support, Thread safety
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Archive::Tar - module for manipulations of tar archives
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Object Methods
+
+=over 4
+
+=item Archive::Tar->new( [$file, $compressed] )
+
+=back
+
+=back
+
+=over 4
+
+=item $tar->read ( $filename|$handle, [$compressed, {opt => 'val'}] )
+
+limit, filter, extract
+
+=back
+
+=over 4
+
+=item $tar->contains_file( $filename )
+
+=back
+
+=over 4
+
+=item $tar->extract( [@filenames] )
+
+=back
+
+=over 4
+
+=item $tar->extract_file( $file, [$extract_path] )
+
+=back
+
+=over 4
+
+=item $tar->list_files( [\@properties] )
+
+=back
+
+=over 4
+
+=item $tar->get_files( [@filenames] )
+
+=back
+
+=over 4
+
+=item $tar->get_content( $file )
+
+=back
+
+=over 4
+
+=item $tar->replace_content( $file, $content )
+
+=back
+
+=over 4
+
+=item $tar->rename( $file, $new_name )
+
+=back
+
+=over 4
+
+=item $tar->remove (@filenamelist)
+
+=back
+
+=over 4
+
+=item $tar->clear
+
+=back
+
+=over 4
+
+=item $tar->write ( [$file, $compressed, $prefix] )
+
+=back
+
+=over 4
+
+=item $tar->add_files( @filenamelist )
+
+=back
+
+=over 4
+
+=item $tar->add_data ( $filename, $data, [$opthashref] )
+
+FILE, HARDLINK, SYMLINK, CHARDEV, BLOCKDEV, DIR, FIFO, SOCKET
+
+=back
+
+=over 4
+
+=item $tar->error( [$BOOL] )
+
+=back
+
+=over 4
+
+=item $tar->setcwd( $cwd );
+
+=back
+
+=over 4
+
+=item Class Methods
+
+=over 4
+
+=item Archive::Tar->create_archive($file, $compressed, @filelist)
+
+=back
+
+=back
+
+=over 4
+
+=item Archive::Tar->iter( $filename, [ $compressed, {opt => $val} ] )
+
+=back
+
+=over 4
+
+=item Archive::Tar->list_archive($file, $compressed, [\@properties])
+
+=back
+
+=over 4
+
+=item Archive::Tar->extract_archive($file, $compressed)
+
+=back
+
+=over 4
+
+=item $bool = Archive::Tar->has_io_string
+
+=back
+
+=over 4
+
+=item $bool = Archive::Tar->has_perlio
+
+=back
+
+=over 4
+
+=item $bool = Archive::Tar->has_zlib_support
+
+=back
+
+=over 4
+
+=item $bool = Archive::Tar->has_bzip2_support
+
+=back
+
+=over 4
+
+=item Archive::Tar->can_handle_compressed_files
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Archive::Tar::FOLLOW_SYMLINK
+
+=item $Archive::Tar::CHOWN
+
+=item $Archive::Tar::CHMOD
+
+=item $Archive::Tar::SAME_PERMISSIONS
+
+=item $Archive::Tar::DO_NOT_USE_PREFIX
+
+=item $Archive::Tar::DEBUG
+
+=item $Archive::Tar::WARN
+
+=item $Archive::Tar::error
+
+=item $Archive::Tar::INSECURE_EXTRACT_MODE
+
+=item $Archive::Tar::HAS_PERLIO
+
+=item $Archive::Tar::HAS_IO_STRING
+
+=back
+
+=item FAQ
+
+What's the minimum perl version required to run Archive::Tar?, Isn't
+Archive::Tar slow?, Isn't Archive::Tar heavier on memory than /bin/tar?,
+Can you lazy-load data instead?, How much memory will an X kb tar file
+need?, What do you do with unsupported filetypes in an archive?, I'm using
+WinZip, or some other non-POSIX client, and files are not being extracted
+properly!, How do I extract only files that have property X from an
+archive?, How do I access .tar.Z files?, How do I handle Unicode strings?
+
+=item CAVEATS
+
+=item TODO
+
+Check if passed in handles are open for read/write, Allow archives to be
+passed in as string, Facilitate processing an opened filehandle of a
+compressed archive
+
+=item SEE ALSO
+
+The GNU tar specification, The PAX format specication, A comparison of GNU
+and POSIX tar standards;
+C<http://www.delorie.com/gnu/docs/tar/tar_114.html>, GNU tar intends to
+switch to POSIX compatibility, A Comparison between various tar
+implementations
+
+=item AUTHOR
+
+=item ACKNOWLEDGEMENTS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Archive::Tar::File - a subclass for in-memory extracted file from
+Archive::Tar
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Accessors
+
+name, mode, uid, gid, size, mtime, chksum, type, linkname, magic, version,
+uname, gname, devmajor, devminor, prefix, raw
+
+=back
+
+=item Methods
+
+=over 4
+
+=item Archive::Tar::File->new( file => $path )
+
+=item Archive::Tar::File->new( data => $path, $data, $opt )
+
+=item Archive::Tar::File->new( chunk => $chunk )
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $file->extract( [ $alternative_name ] )
+
+=back
+
+=over 4
+
+=item $path = $file->full_path
+
+=back
+
+=over 4
+
+=item $bool = $file->validate
+
+=back
+
+=over 4
+
+=item $bool = $file->has_content
+
+=back
+
+=over 4
+
+=item $content = $file->get_content
+
+=back
+
+=over 4
+
+=item $cref = $file->get_content_by_ref
+
+=back
+
+=over 4
+
+=item $bool = $file->replace_content( $content )
+
+=back
+
+=over 4
+
+=item $bool = $file->rename( $new_name )
+
+=back
+
+=over 4
+
+=item Convenience methods
+
+$file->is_file, $file->is_dir, $file->is_hardlink, $file->is_symlink,
+$file->is_chardev, $file->is_blockdev, $file->is_fifo, $file->is_socket,
+$file->is_longlink, $file->is_label, $file->is_unknown
+
+=back
+
+=head2 Attribute::Handlers - Simpler definition of attribute handlers
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+[0], [1], [2], [3], [4], [5], [6], [7]
+
+=over 4
+
+=item Typed lexicals
+
+=item Type-specific attribute handlers
+
+=item Non-interpretive attribute handlers
+
+=item Phase-specific attribute handlers
+
+=item Attributes as C<tie> interfaces
+
+=back
+
+=item EXAMPLES
+
+=item UTILITY FUNCTIONS
+
+findsym
+
+=item DIAGNOSTICS
+
+C<Bad attribute type: ATTR(%s)>, C<Attribute handler %s doesn't handle %s
+attributes>, C<Declaration of %s attribute in package %s may clash with
+future reserved word>, C<Can't have two ATTR specifiers on one subroutine>,
+C<Can't autotie a %s>, C<Internal error: %s symbol went missing>, C<Won't
+be able to apply END handler>
+
+=item AUTHOR
+
+=item BUGS
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 AutoLoader - load subroutines only on demand
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Subroutine Stubs
+
+=item Using B<AutoLoader>'s AUTOLOAD Subroutine
+
+=item Overriding B<AutoLoader>'s AUTOLOAD Subroutine
+
+=item Package Lexicals
+
+=item Not Using AutoLoader
+
+=item B<AutoLoader> vs. B<SelfLoader>
+
+=back
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 AutoSplit - split a package for autoloading
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$keep, $check, $modtime
+
+=over 4
+
+=item Multiple packages
+
+=back
+
+=item DIAGNOSTICS
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 B - The Perl Compiler Backend
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OVERVIEW
+
+=item Utility Functions
+
+=over 4
+
+=item Functions Returning C<B::SV>, C<B::AV>, C<B::HV>, and C<B::CV>
+objects
+
+sv_undef, sv_yes, sv_no, svref_2object(SVREF), amagic_generation, init_av,
+check_av, unitcheck_av, begin_av, end_av, comppadlist, regex_padav, main_cv
+
+=item Functions for Examining the Symbol Table
+
+walksymtable(SYMREF, METHOD, RECURSE, PREFIX)
+
+=item Functions Returning C<B::OP> objects or for walking op trees
+
+main_root, main_start, walkoptree(OP, METHOD), walkoptree_debug(DEBUG)
+
+=item Miscellaneous Utility Functions
+
+ppname(OPNUM), hash(STR), cast_I32(I), minus_c, cstring(STR),
+perlstring(STR), class(OBJ), threadsv_names
+
+=item Exported utility variabiles
+
+@optype, @specialsv_name
+
+=back
+
+=item OVERVIEW OF CLASSES
+
+=over 4
+
+=item SV-RELATED CLASSES
+
+=item B::SV Methods
+
+REFCNT, FLAGS, object_2svref
+
+=item B::IV Methods
+
+IV, IVX, UVX, int_value, needs64bits, packiv
+
+=item B::NV Methods
+
+NV, NVX
+
+=item B::RV Methods
+
+RV
+
+=item B::PV Methods
+
+PV, RV, PVX
+
+=item B::PVMG Methods
+
+MAGIC, SvSTASH
+
+=item B::MAGIC Methods
+
+MOREMAGIC, precomp, PRIVATE, TYPE, FLAGS, OBJ, PTR, REGEX
+
+=item B::PVLV Methods
+
+TARGOFF, TARGLEN, TYPE, TARG
+
+=item B::BM Methods
+
+USEFUL, PREVIOUS, RARE, TABLE
+
+=item B::GV Methods
+
+is_empty, NAME, SAFENAME, STASH, SV, IO, FORM, AV, HV, EGV, CV, CVGEN,
+LINE, FILE, FILEGV, GvREFCNT, FLAGS
+
+=item B::IO Methods
+
+LINES, PAGE, PAGE_LEN, LINES_LEFT, TOP_NAME, TOP_GV, FMT_NAME, FMT_GV,
+BOTTOM_NAME, BOTTOM_GV, SUBPROCESS, IoTYPE, IoFLAGS, IsSTD
+
+=item B::AV Methods
+
+FILL, MAX, ARRAY, ARRAYelt, OFF, AvFLAGS
+
+=item B::CV Methods
+
+STASH, START, ROOT, GV, FILE, DEPTH, PADLIST, OUTSIDE, OUTSIDE_SEQ, XSUB,
+XSUBANY, CvFLAGS, const_sv
+
+=item B::HV Methods
+
+FILL, MAX, KEYS, RITER, NAME, ARRAY, PMROOT
+
+=item OP-RELATED CLASSES
+
+=item B::OP Methods
+
+next, sibling, name, ppaddr, desc, targ, type, opt, flags, private, spare
+
+=item B::UNOP METHOD
+
+first
+
+=item B::BINOP METHOD
+
+last
+
+=item B::LOGOP METHOD
+
+other
+
+=item B::LISTOP METHOD
+
+children
+
+=item B::PMOP Methods
+
+pmreplroot, pmreplstart, pmnext, pmregexp, pmflags, extflags, precomp,
+pmoffset
+
+=item B::SVOP METHOD
+
+sv, gv
+
+=item B::PADOP METHOD
+
+padix
+
+=item B::PVOP METHOD
+
+pv
+
+=item B::LOOP Methods
+
+redoop, nextop, lastop
+
+=item B::COP Methods
+
+label, stash, stashpv, file, cop_seq, arybase, line, warnings, io, hints,
+hints_hash
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 B::Concise - Walk Perl syntax tree, printing concise info about ops
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLE
+
+=item OPTIONS
+
+=over 4
+
+=item Options for Opcode Ordering
+
+B<-basic>, B<-exec>, B<-tree>
+
+=item Options for Line-Style
+
+B<-concise>, B<-terse>, B<-linenoise>, B<-debug>, B<-env>
+
+=item Options for tree-specific formatting
+
+B<-compact>, B<-loose>, B<-vt>, B<-ascii>
+
+=item Options controlling sequence numbering
+
+B<-base>I<n>, B<-bigendian>, B<-littleendian>
+
+=item Other options
+
+B<-src>, B<-stash="somepackage">, B<-main>, B<-nomain>, B<-nobanner>,
+B<-banner>, B<-banneris> => subref
+
+=item Option Stickiness
+
+=back
+
+=item ABBREVIATIONS
+
+=over 4
+
+=item OP class abbreviations
+
+=item OP flags abbreviations
+
+=back
+
+=item FORMATTING SPECIFICATIONS
+
+=over 4
+
+=item Special Patterns
+
+B<(x(>I<exec_text>B<;>I<basic_text>B<)x)>, B<(*(>I<text>B<)*)>,
+B<(*(>I<text1>B<;>I<text2>B<)*)>, B<(?(>I<text1>B<#>I<var>I<Text2>B<)?)>,
+B<~>
+
+=item # Variables
+
+B<#>I<var>, B<#>I<var>I<N>, B<#>I<Var>, B<#addr>, B<#arg>, B<#class>,
+B<#classsym>, B<#coplabel>, B<#exname>, B<#extarg>, B<#firstaddr>,
+B<#flags>, B<#flagval>, B<#hints>, B<#hintsval>, B<#hyphseq>, B<#label>,
+B<#lastaddr>, B<#name>, B<#NAME>, B<#next>, B<#nextaddr>, B<#noise>,
+B<#private>, B<#privval>, B<#seq>, B<#seqnum>, B<#opt>, B<#sibaddr>,
+B<#svaddr>, B<#svclass>, B<#svval>, B<#targ>, B<#targarg>, B<#targarglife>,
+B<#typenum>
+
+=back
+
+=item One-Liner Command tips
+
+perl -MO=Concise,bar foo.pl, perl -MDigest::MD5=md5 -MO=Concise,md5 -e1,
+perl -MPOSIX -MO=Concise,_POSIX_ARG_MAX -e1, perl -MPOSIX -MO=Concise,a -e
+'print _POSIX_SAVED_IDS', perl -MPOSIX -MO=Concise,a -e 'sub
+a{_POSIX_SAVED_IDS}', perl -MB::Concise -e
+'B::Concise::compile("-exec","-src", \%B::Concise::)->()'
+
+=item Using B::Concise outside of the O framework
+
+=over 4
+
+=item Example: Altering Concise Renderings
+
+=item set_style()
+
+=item set_style_standard($name)
+
+=item add_style ()
+
+=item add_callback ()
+
+=item Running B::Concise::compile()
+
+=item B::Concise::reset_sequence()
+
+=item Errors
+
+=back
+
+=item AUTHOR
+
+=back
+
+=head2 B::Debug - Walk Perl syntax tree, printing debug info about ops
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+=item Changes
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 B::Deparse - Perl compiler backend to produce perl code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+B<-d>, B<-f>I<FILE>, B<-l>, B<-p>, B<-P>, B<-q>, B<-s>I<LETTERS>, B<C>,
+B<i>I<NUMBER>, B<T>, B<v>I<STRING>B<.>, B<-x>I<LEVEL>
+
+=item USING B::Deparse AS A MODULE
+
+=over 4
+
+=item Synopsis
+
+=item Description
+
+=item new
+
+=item ambient_pragmas
+
+strict, $[, bytes, utf8, integer, re, warnings, hint_bits, warning_bits,
+%^H
+
+=item coderef2text
+
+=back
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 B::Lint - Perl lint
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS AND LINT CHECKS
+
+B<magic-diamond>, B<context>, B<implicit-read> and B<implicit-write>,
+B<bare-subs>, B<dollar-underscore>, B<private-names>, B<undefined-subs>,
+B<regexp-variables>, B<all>, B<none>
+
+=item NON LINT-CHECK OPTIONS
+
+B<-u Package>
+
+=item EXTENDING LINT
+
+=item TODO
+
+while(<FH>) stomps $_, strict oo, unchecked system calls, more tests,
+validate against older perls
+
+=item BUGS
+
+=item AUTHOR
+
+=item ACKNOWLEDGEMENTS
+
+=back
+
+=head2 B::Lint::Debug - Adds debugging stringification to B::
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 B::O, O - Generic interface to Perl Compiler backends
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONVENTIONS
+
+=item IMPLEMENTATION
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 B::Showlex - Show lexical variables used in functions or files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=over 4
+
+=item OPTIONS
+
+=back
+
+=item SEE ALSO
+
+=item TODO
+
+=item AUTHOR
+
+=back
+
+=head2 B::Terse - Walk Perl syntax tree, printing terse info about ops
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 B::Xref - Generates cross reference reports for Perl programs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+C<-oFILENAME>, C<-r>, C<-d>, C<-D[tO]>
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 Benchmark - benchmark running times of Perl code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Methods
+
+new, debug, iters
+
+=item Standard Exports
+
+timeit(COUNT, CODE), timethis ( COUNT, CODE, [ TITLE, [ STYLE ]] ),
+timethese ( COUNT, CODEHASHREF, [ STYLE ] ), timediff ( T1, T2 ), timestr (
+TIMEDIFF, [ STYLE, [ FORMAT ] ] )
+
+=item Optional Exports
+
+clearcache ( COUNT ), clearallcache ( ), cmpthese ( COUNT, CODEHASHREF, [
+STYLE ] ), cmpthese ( RESULTSHASHREF, [ STYLE ] ), countit(TIME, CODE),
+disablecache ( ), enablecache ( ), timesum ( T1, T2 )
+
+=item :hireswallclock
+
+=back
+
+=item NOTES
+
+=item EXAMPLES
+
+=item INHERITANCE
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item MODIFICATION HISTORY
+
+=back
+
+=head2 CGI - Handle Common Gateway Interface requests and responses
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item PROGRAMMING STYLE
+
+=item CALLING CGI.PM ROUTINES
+
+=item CREATING A NEW QUERY OBJECT (OBJECT-ORIENTED STYLE):
+
+=item CREATING A NEW QUERY OBJECT FROM AN INPUT FILE
+
+=item FETCHING A LIST OF KEYWORDS FROM THE QUERY:
+
+=item FETCHING THE NAMES OF ALL THE PARAMETERS PASSED TO YOUR SCRIPT:
+
+=item FETCHING THE VALUE OR VALUES OF A SINGLE NAMED PARAMETER:
+
+=item SETTING THE VALUE(S) OF A NAMED PARAMETER:
+
+=item APPENDING ADDITIONAL VALUES TO A NAMED PARAMETER:
+
+=item IMPORTING ALL PARAMETERS INTO A NAMESPACE:
+
+=item DELETING A PARAMETER COMPLETELY:
+
+=item DELETING ALL PARAMETERS:
+
+=item HANDLING NON-URLENCODED ARGUMENTS
+
+=item DIRECT ACCESS TO THE PARAMETER LIST:
+
+=item FETCHING THE PARAMETER LIST AS A HASH:
+
+=item SAVING THE STATE OF THE SCRIPT TO A FILE:
+
+=item RETRIEVING CGI ERRORS
+
+=item USING THE FUNCTION-ORIENTED INTERFACE
+
+B<:cgi>, B<:form>, B<:html2>, B<:html3>, B<:html4>, B<:netscape>, B<:html>,
+B<:standard>, B<:all>
+
+=item PRAGMAS
+
+-any, -compile, -nosticky, -tabindex, -no_undef_params, -no_xhtml, -utf8,
+-nph, -newstyle_urls, -oldstyle_urls, -autoload, -no_debug, -debug,
+-private_tempfiles
+
+=item SPECIAL FORMS FOR IMPORTING HTML-TAG FUNCTIONS
+
+1. start_table() (generates a <table> tag), 2. end_table() (generates a
+</table> tag), 3. start_ul() (generates a <ul> tag), 4. end_ul() (generates
+a </ul> tag)
+
+=back
+
+=item GENERATING DYNAMIC DOCUMENTS
+
+=over 4
+
+=item CREATING A STANDARD HTTP HEADER:
+
+=item GENERATING A REDIRECTION HEADER
+
+=item CREATING THE HTML DOCUMENT HEADER
+
+B<Parameters:>, 4, 5, 6..
+
+=item ENDING THE HTML DOCUMENT:
+
+=item CREATING A SELF-REFERENCING URL THAT PRESERVES STATE INFORMATION:
+
+=item OBTAINING THE SCRIPT'S URL
+
+B<-absolute>, B<-relative>, B<-full>, B<-path> (B<-path_info>), B<-query>
+(B<-query_string>), B<-base>, B<-rewrite>
+
+=item MIXING POST AND URL PARAMETERS
+
+=back
+
+=item CREATING STANDARD HTML ELEMENTS:
+
+=over 4
+
+=item PROVIDING ARGUMENTS TO HTML SHORTCUTS
+
+=item THE DISTRIBUTIVE PROPERTY OF HTML SHORTCUTS
+
+=item HTML SHORTCUTS AND LIST INTERPOLATION
+
+=item NON-STANDARD HTML SHORTCUTS
+
+=item AUTOESCAPING HTML
+
+$escaped_string = escapeHTML("unescaped string");, $charset =
+charset([$charset]);, $flag = autoEscape([$flag]);
+
+=item PRETTY-PRINTING HTML
+
+=back
+
+=item CREATING FILL-OUT FORMS:
+
+=over 4
+
+=item CREATING AN ISINDEX TAG
+
+=item STARTING AND ENDING A FORM
+
+B<application/x-www-form-urlencoded>, B<multipart/form-data>
+
+=item FORM ELEMENTS
+
+B<-name>, B<-value>, B<-values>, B<-tabindex>, B<-id>, B<-override>,
+B<-onChange>, B<-onFocus>, B<-onBlur>, B<-onMouseOver>, B<-onMouseOut>,
+B<-onSelect>
+
+=item CREATING A TEXT FIELD
+
+B<Parameters>
+
+=item CREATING A BIG TEXT FIELD
+
+=item CREATING A PASSWORD FIELD
+
+=item CREATING A FILE UPLOAD FIELD
+
+B<Parameters>
+
+=item PROCESSING A FILE UPLOAD FIELD
+
+=item CREATING A POPUP MENU
+
+=item CREATING AN OPTION GROUP
+
+=item CREATING A SCROLLING LIST
+
+B<Parameters:>
+
+=item CREATING A GROUP OF RELATED CHECKBOXES
+
+B<Parameters:>
+
+=item CREATING A STANDALONE CHECKBOX
+
+B<Parameters:>
+
+=item CREATING A RADIO BUTTON GROUP
+
+B<Parameters:>
+
+=item CREATING A SUBMIT BUTTON
+
+B<Parameters:>
+
+=item CREATING A RESET BUTTON
+
+=item CREATING A DEFAULT BUTTON
+
+=item CREATING A HIDDEN FIELD
+
+B<Parameters:>
+
+=item CREATING A CLICKABLE IMAGE BUTTON
+
+B<Parameters:>, 3. The third option (-align, optional) is an alignment
+type, and may be TOP, BOTTOM or MIDDLE
+
+=item CREATING A JAVASCRIPT ACTION BUTTON
+
+=back
+
+=item HTTP COOKIES
+
+1. an expiration time, 2. a domain, 3. a path, 4. a "secure" flag,
+B<-name>, B<-value>, B<-path>, B<-domain>, B<-expires>, B<-secure>
+
+=item WORKING WITH FRAMES
+
+1. Create a <Frameset> document, 2. Specify the destination for the
+document in the HTTP header, 3. Specify the destination for the document in
+the <form> tag
+
+=item SUPPORT FOR JAVASCRIPT
+
+B<onLoad>, B<onUnload>, B<onSubmit>, B<onClick>, B<onChange>, B<onFocus>,
+B<onBlur>, B<onSelect>, B<onMouseOver>, B<onMouseOut>
+
+=item LIMITED SUPPORT FOR CASCADING STYLE SHEETS
+
+=item DEBUGGING
+
+=over 4
+
+=item DUMPING OUT ALL THE NAME/VALUE PAIRS
+
+=back
+
+=item FETCHING ENVIRONMENT VARIABLES
+
+B<Accept()>, B<raw_cookie()>, B<user_agent()>, B<path_info()>,
+B<path_translated()>, B<remote_host()>, B<remote_addr()>, B<script_name()>
+Return the script name as a partial URL, for self-refering scripts,
+B<referer()>, B<auth_type ()>, B<server_name ()>, B<virtual_host ()>,
+B<server_port ()>, B<virtual_port ()>, B<server_software ()>, B<remote_user
+()>, B<user_name ()>, B<request_method()>, B<content_type()>, B<http()>,
+B<https()>
+
+=item USING NPH SCRIPTS
+
+In the B<use> statement, By calling the B<nph()> method:, By using B<-nph>
+parameters
+
+=item Server Push
+
+multipart_init(), multipart_start(), multipart_end(), multipart_final()
+
+=item Avoiding Denial of Service Attacks
+
+B<$CGI::POST_MAX>, B<$CGI::DISABLE_UPLOADS>, B<1. On a script-by-script
+basis>, B<2. Globally for all scripts>
+
+=item COMPATIBILITY WITH CGI-LIB.PL
+
+=item AUTHOR INFORMATION
+
+=item CREDITS
+
+Matt Heffron (heffron@falstaff.css.beckman.com), James Taylor
+(james.taylor@srs.gov), Scott Anguish <sanguish@digifix.com>, Mike Jewell
+(mlj3u@virginia.edu), Timothy Shimmin (tes@kbs.citri.edu.au), Joergen Haegg
+(jh@axis.se), Laurent Delfosse (delfosse@delfosse.com), Richard Resnick
+(applepi1@aol.com), Craig Bishop (csb@barwonwater.vic.gov.au), Tony Curtis
+(tc@vcpc.univie.ac.at), Tim Bunce (Tim.Bunce@ig.co.uk), Tom Christiansen
+(tchrist@convex.com), Andreas Koenig (k@franz.ww.TU-Berlin.DE), Tim
+MacKenzie (Tim.MacKenzie@fulcrum.com.au), Kevin B. Hendricks
+(kbhend@dogwood.tyler.wm.edu), Stephen Dahmen (joyfire@inxpress.net), Ed
+Jordan (ed@fidalgo.net), David Alan Pisoni (david@cnation.com), Doug
+MacEachern (dougm@opengroup.org), Robin Houston (robin@oneworld.org),
+...and many many more..
+
+=item A COMPLETE EXAMPLE OF A SIMPLE FORM-BASED SCRIPT
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Apache - Backward compatibility module for CGI.pm
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item AUTHOR INFORMATION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Carp, B<CGI::Carp> - CGI routines for writing to the HTTPD (or
+other) error log
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item REDIRECTING ERROR MESSAGES
+
+=item MAKING PERL ERRORS APPEAR IN THE BROWSER WINDOW
+
+=over 4
+
+=item Changing the default message
+
+=back
+
+=item DOING MORE THAN PRINTING A MESSAGE IN THE EVENT OF PERL ERRORS
+
+=item MAKING WARNINGS APPEAR AS HTML COMMENTS
+
+=item OVERRIDING THE NAME OF THE PROGRAM
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Cookie - Interface to Netscape Cookies
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USING CGI::Cookie
+
+B<1. expiration date>, B<2. domain>, B<3. path>, B<4. secure flag>, B<4.
+httponly flag>
+
+=over 4
+
+=item Creating New Cookies
+
+=item Sending the Cookie to the Browser
+
+=item Recovering Previous Cookies
+
+=item Manipulating Cookies
+
+B<name()>, B<value()>, B<domain()>, B<path()>, B<expires()>
+
+=back
+
+=item AUTHOR INFORMATION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Fast - CGI Interface for Fast CGI
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OTHER PIECES OF THE PUZZLE
+
+=item WRITING FASTCGI PERL SCRIPTS
+
+=item INSTALLING FASTCGI SCRIPTS
+
+=item USING FASTCGI SCRIPTS AS CGI SCRIPTS
+
+=item EXTERNAL FASTCGI SERVER INVOCATION
+
+FCGI_SOCKET_PATH, FCGI_LISTEN_QUEUE
+
+=item CAVEATS
+
+=item AUTHOR INFORMATION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Pretty - module to produce nicely formatted HTML code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Recommendation for when to use CGI::Pretty
+
+=item Tags that won't be formatted
+
+=item Customizing the Indenting
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Push - Simple Interface to Server Push
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USING CGI::Push
+
+-next_page, -last_page, -type, -delay, -cookie, -target, -expires, -nph
+
+=over 4
+
+=item Heterogeneous Pages
+
+=item Changing the Page Delay on the Fly
+
+=back
+
+=item INSTALLING CGI::Push SCRIPTS
+
+=item AUTHOR INFORMATION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Switch - Backward compatibility module for defunct CGI::Switch
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item AUTHOR INFORMATION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 CGI::Util - Internal utilities used by CGI module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR INFORMATION
+
+=item SEE ALSO
+
+=back
+
+=head2 CORE - Pseudo-namespace for Perl's core routines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OVERRIDING CORE FUNCTIONS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 CPAN - query, download and build perl modules from CPAN sites
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item CPAN::shell([$prompt, $command]) Starting Interactive Mode
+
+Searching for authors, bundles, distribution files and modules, C<get>,
+C<make>, C<test>, C<install>, C<clean> modules or distributions, C<readme>,
+C<perldoc>, C<look> module or distribution, C<ls> author, C<ls>
+globbing_expression, C<failed>, Persistence between sessions, The C<force>
+and the C<fforce> pragma, Lockfile, Signals
+
+=item CPAN::Shell
+
+=item autobundle
+
+=item hosts
+
+=item mkmyconfig
+
+=item recent ***EXPERIMENTAL COMMAND***
+
+=item recompile
+
+=item report Bundle|Distribution|Module
+
+=item smoke ***EXPERIMENTAL COMMAND***
+
+=item upgrade [Module|/Regex/]...
+
+=item The four C<CPAN::*> Classes: Author, Bundle, Module, Distribution
+
+=item Integrating local directories
+
+=item Redirection
+
+=back
+
+=item CONFIGURATION
+
+completion support, displaying some help: o conf help, displaying current
+values: o conf [KEY], changing of scalar values: o conf KEY VALUE, changing
+of list values: o conf KEY SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST, reverting to
+saved: o conf defaults, saving the config: o conf commit
+
+=over 4
+
+=item Config Variables
+
+C<o conf E<lt>scalar optionE<gt>>, C<o conf E<lt>scalar optionE<gt>
+E<lt>valueE<gt>>, C<o conf E<lt>list optionE<gt>>, C<o conf E<lt>list
+optionE<gt> [shift|pop]>, C<o conf E<lt>list optionE<gt>
+[unshift|push|splice] E<lt>listE<gt>>, interactive editing: o conf init
+[MATCH|LIST]
+
+=item CPAN::anycwd($path): Note on config variable getcwd
+
+cwd, getcwd, fastcwd, backtickcwd
+
+=item Note on the format of the urllist parameter
+
+=item The urllist parameter has CD-ROM support
+
+=item Maintaining the urllist parameter
+
+=item The C<requires> and C<build_requires> dependency declarations
+
+=item Configuration for individual distributions (I<Distroprefs>)
+
+=item Filenames
+
+=item Fallback Data::Dumper and Storable
+
+=item Blueprint
+
+=item Language Specs
+
+comment [scalar], cpanconfig [hash], depends [hash] *** EXPERIMENTAL
+FEATURE ***, disabled [boolean], features [array] *** EXPERIMENTAL FEATURE
+***, goto [string], install [hash], make [hash], match [hash], patches
+[array], pl [hash], test [hash]
+
+=item Processing Instructions
+
+args [array], commandline, eexpect [hash], env [hash], expect [array]
+
+=item Schema verification with C<Kwalify>
+
+=item Example Distroprefs Files
+
+=back
+
+=item PROGRAMMER'S INTERFACE
+
+expand($type,@things), expandany(@things), Programming Examples
+
+=over 4
+
+=item Methods in the other Classes
+
+CPAN::Author::as_glimpse(), CPAN::Author::as_string(),
+CPAN::Author::email(), CPAN::Author::fullname(), CPAN::Author::name(),
+CPAN::Bundle::as_glimpse(), CPAN::Bundle::as_string(),
+CPAN::Bundle::clean(), CPAN::Bundle::contains(),
+CPAN::Bundle::force($method,@args), CPAN::Bundle::get(),
+CPAN::Bundle::inst_file(), CPAN::Bundle::inst_version(),
+CPAN::Bundle::uptodate(), CPAN::Bundle::install(), CPAN::Bundle::make(),
+CPAN::Bundle::readme(), CPAN::Bundle::test(),
+CPAN::Distribution::as_glimpse(), CPAN::Distribution::as_string(),
+CPAN::Distribution::author, CPAN::Distribution::pretty_id(),
+CPAN::Distribution::base_id(), CPAN::Distribution::clean(),
+CPAN::Distribution::containsmods(), CPAN::Distribution::cvs_import(),
+CPAN::Distribution::dir(), CPAN::Distribution::force($method,@args),
+CPAN::Distribution::get(), CPAN::Distribution::install(),
+CPAN::Distribution::install_tested(), CPAN::Distribution::isa_perl(),
+CPAN::Distribution::look(), CPAN::Distribution::make(),
+CPAN::Distribution::perldoc(), CPAN::Distribution::prefs(),
+CPAN::Distribution::prereq_pm(), CPAN::Distribution::readme(),
+CPAN::Distribution::reports(), CPAN::Distribution::read_yaml(),
+CPAN::Distribution::test(), CPAN::Distribution::uptodate(),
+CPAN::Index::force_reload(), CPAN::Index::reload(), CPAN::InfoObj::dump(),
+CPAN::Module::as_glimpse(), CPAN::Module::as_string(),
+CPAN::Module::clean(), CPAN::Module::cpan_file(),
+CPAN::Module::cpan_version(), CPAN::Module::cvs_import(),
+CPAN::Module::description(), CPAN::Module::distribution(),
+CPAN::Module::dslip_status(), CPAN::Module::force($method,@args),
+CPAN::Module::get(), CPAN::Module::inst_file(),
+CPAN::Module::available_file(), CPAN::Module::inst_version(),
+CPAN::Module::available_version(), CPAN::Module::install(),
+CPAN::Module::look(), CPAN::Module::make(),
+CPAN::Module::manpage_headline(), CPAN::Module::perldoc(),
+CPAN::Module::readme(), CPAN::Module::reports(), CPAN::Module::test(),
+CPAN::Module::uptodate(), CPAN::Module::userid()
+
+=item Cache Manager
+
+=item Bundles
+
+=back
+
+=item PREREQUISITES
+
+=item UTILITIES
+
+=over 4
+
+=item Finding packages and VERSION
+
+=item Debugging
+
+o debug package.., o debug -package.., o debug all, o debug number
+
+=item Floppy, Zip, Offline Mode
+
+=item Basic Utilities for Programmers
+
+has_inst($module), has_usable($module), instance($module)
+
+=back
+
+=item SECURITY
+
+=over 4
+
+=item Cryptographically signed modules
+
+=back
+
+=item EXPORT
+
+=item ENVIRONMENT
+
+=item POPULATE AN INSTALLATION WITH LOTS OF MODULES
+
+=item WORKING WITH CPAN.pm BEHIND FIREWALLS
+
+=over 4
+
+=item Three basic types of firewalls
+
+http firewall, ftp firewall, One-way visibility, SOCKS, IP Masquerade
+
+=item Configuring lynx or ncftp for going through a firewall
+
+=back
+
+=item FAQ
+
+1), 2), 3), 4), 5), 6), 7), 8), 9), 10), 11), 12), 13), 14), 15), 16), 17),
+18)
+
+=item COMPATIBILITY
+
+=over 4
+
+=item OLD PERL VERSIONS
+
+=item CPANPLUS
+
+=back
+
+=item SECURITY ADVICE
+
+=item BUGS
+
+=item AUTHOR
+
+=item LICENSE
+
+=item TRANSLATIONS
+
+=item SEE ALSO
+
+=back
+
+=head2 CPAN::API::HOWTO - a recipe book for programming with CPAN.pm
+
+=over 4
+
+=item RECIPES
+
+=over 4
+
+=item What distribution contains a particular module?
+
+=item What modules does a particular distribution contain?
+
+=back
+
+=item SEE ALSO
+
+=item LICENSE
+
+=item AUTHOR
+
+=back
+
+=head2 CPAN::Distroprefs -- read and match distroprefs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item INTERFACE
+
+a CPAN::Distroprefs::Result object, C<undef>, indicating that no prefs
+files remain to be found
+
+=item RESULTS
+
+=over 4
+
+=item Common
+
+=item Errors
+
+=item Successes
+
+=back
+
+=item PREFS
+
+=item LICENSE
+
+=back
+
+=head2 CPAN::FirstTime - Utility for CPAN::Config file Initialization
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+auto_commit, build_cache, build_dir, build_dir_reuse,
+build_requires_install_policy, cache_metadata, check_sigs, colorize_output,
+colorize_print, colorize_warn, colorize_debug, commandnumber_in_prompt,
+connect_to_internet_ok, ftp_passive, ftpstats_period, ftpstats_size,
+getcwd, halt_on_failure, histfile, histsize, inactivity_timeout,
+index_expire, inhibit_startup_message, keep_source_where,
+load_module_verbosity, makepl_arg, make_arg, make_install_arg,
+make_install_make_command, mbuildpl_arg, mbuild_arg, mbuild_install_arg,
+mbuild_install_build_command, pager, prefer_installer, prefs_dir,
+prerequisites_policy, randomize_urllist, scan_cache, shell,
+show_unparsable_versions, show_upload_date, show_zero_versions,
+tar_verbosity, term_is_latin, term_ornaments, test_report,
+perl5lib_verbosity, trust_test_report_history, use_sqlite, version_timeout,
+yaml_load_code, yaml_module
+
+=over 4
+
+=item LICENSE
+
+=back
+
+=head2 CPAN::Kwalify - Interface between CPAN.pm and Kwalify.pm
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+_validate($schema_name, $data, $file, $doc), yaml($schema_name)
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 CPAN::Version - utility functions to compare CPAN versions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item LICENSE
+
+=back
+
+=head2 CPANPLUS - API & CLI access to the CPAN mirrors
+
+=over 4
+
+=item SYNOPSIS
+
+=item GUIDE TO DOCUMENTATION
+
+=over 4
+
+=item GENERAL USAGE
+
+=item API REFERENCE
+
+=back
+
+=back
+
+=over 4
+
+=item COMMANDLINE TOOLS
+
+=over 4
+
+=item STARTING AN INTERACTIVE SHELL
+
+=item BUILDING PACKAGES
+
+=item $bool = install( Module::Name | /A/AU/AUTHOR/Module-Name-1.tgz )
+
+=item $where = fetch( Module::Name | /A/AU/AUTHOR/Module-Name-1.tgz )
+
+=item $where = get( Module::Name | /A/AU/AUTHOR/Module-Name-1.tgz )
+
+=item shell()
+
+=back
+
+=item FAQ
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=item CONTACT INFORMATION
+
+Bug reporting: I<bug-cpanplus@rt.cpan.org>, Questions & suggestions:
+I<cpanplus-devel@lists.sourceforge.net>
+
+=back
+
+=head2 CPANPLUS::Backend
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ENVIRONMENT
+
+=item METHODS
+
+=over 4
+
+=item $cb = CPANPLUS::Backend->new( [CONFIGURE_OBJ] )
+
+Provide a valid C<CPANPLUS::Configure> object, No arguments
+
+=back
+
+=back
+
+=over 4
+
+=item $href = $cb->module_tree( [@modules_names_list] )
+
+=back
+
+=over 4
+
+=item $href = $cb->author_tree( [@author_names_list] )
+
+=back
+
+=over 4
+
+=item $conf = $cb->configure_object;
+
+=back
+
+=over 4
+
+=item $su = $cb->selfupdate_object;
+
+=back
+
+=over 4
+
+=item @mods = $cb->search( type => TYPE, allow => AREF, [data => AREF,
+verbose => BOOL] )
+
+=back
+
+=over 4
+
+=item $backend_rv = $cb->fetch( modules => \@mods )
+
+=item $backend_rv = $cb->extract( modules => \@mods )
+
+=item $backend_rv = $cb->install( modules => \@mods )
+
+=item $backend_rv = $cb->readme( modules => \@mods )
+
+=item $backend_rv = $cb->files( modules => \@mods )
+
+=item $backend_rv = $cb->distributions( modules => \@mods )
+
+=back
+
+=over 4
+
+=item $mod_obj = $cb->parse_module( module =>
+$modname|$distname|$modobj|URI|PATH )
+
+Text::Bastardize, Text-Bastardize, Text-Bastardize-1.06,
+AYRNIEU/Text-Bastardize, AYRNIEU/Text-Bastardize-1.06,
+AYRNIEU/Text-Bastardize-1.06.tar.gz,
+http://example.com/Text-Bastardize-1.06.tar.gz,
+file:///tmp/Text-Bastardize-1.06.tar.gz, /tmp/Text-Bastardize-1.06,
+./Text-Bastardize-1.06
+
+=back
+
+=over 4
+
+=item $bool = $cb->reload_indices( [update_source => BOOL, verbose => BOOL]
+);
+
+=back
+
+=over 4
+
+=item $bool = $cb->flush(CACHE_NAME)
+
+C<methods>, C<hosts>, C<modules>, C<lib>, C<load>, C<all>
+
+=back
+
+=over 4
+
+=item @mods = $cb->installed()
+
+=back
+
+=over 4
+
+=item $bool = $cb->local_mirror([path => '/dir/to/save/to', index_files =>
+BOOL, force => BOOL, verbose => BOOL] )
+
+path, index_files, force, verbose
+
+=back
+
+=over 4
+
+=item $file = $cb->autobundle([path => OUTPUT_PATH, force => BOOL, verbose
+=> BOOL])
+
+=back
+
+=over 4
+
+=item $bool = $cb->save_state
+
+=back
+
+=over 4
+
+=item CUSTOM MODULE SOURCES
+
+=over 4
+
+=item %files = $cb->list_custom_sources
+
+=back
+
+=back
+
+=over 4
+
+=item $local_index = $cb->add_custom_source( uri => URI, [verbose => BOOL]
+);
+
+=back
+
+=over 4
+
+=item $local_index = $cb->remove_custom_source( uri => URI, [verbose =>
+BOOL] );
+
+=back
+
+=over 4
+
+=item $bool = $cb->update_custom_source( [remote => URI] );
+
+=back
+
+=over 4
+
+=item $file = $cb->write_custom_source_index( path =>
+/path/to/package/root, [to => /path/to/index/file, verbose => BOOL] );
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUS::Backend::RV
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item new( ok => BOOL, args => DATA, rv => DATA, [function => $method_name]
+)
+
+ok, args, rv, function
+
+=back
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 CPANPLUS::Config
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONFIGURATION
+
+=back
+
+=over 4
+
+=item Section 'conf'
+
+hosts
+
+=back
+
+base
+
+buildflags
+
+cpantest
+
+cpantest_mx
+
+debug
+
+dist_type
+
+email
+
+extractdir
+
+fetchdir
+
+flush
+
+force
+
+lib
+
+makeflags
+
+makemakerflags
+
+md5
+
+no_update
+
+passive
+
+prefer_bin
+
+prefer_makefile
+
+prereqs
+
+shell
+
+show_startup_tip
+
+signature
+
+skiptest
+
+storable
+
+timeout
+
+verbose
+
+write_install_log
+
+source_engine
+
+cpantest_reporter_args
+
+editor
+
+make
+
+pager
+
+shell
+
+sudo
+
+perlwrapper
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUS::Configure
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item $Configure = CPANPLUS::Configure->new( load_configs => BOOL )
+
+load_configs
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $Configure->init( [rescan => BOOL])
+
+=back
+
+=over 4
+
+=item can_save( [$config_location] )
+
+=back
+
+=over 4
+
+=item $file = $conf->save( [$package_name] )
+
+=back
+
+=over 4
+
+=item options( type => TYPE )
+
+=back
+
+=over 4
+
+=item ACCESSORS
+
+=over 4
+
+=item get_SOMETHING( ITEM, [ITEM, ITEM, ... ] );
+
+=item set_SOMETHING( ITEM => VAL, [ITEM => VAL, ITEM => VAL, ... ] );
+
+=item add_SOMETHING( ITEM => VAL, [ITEM => VAL, ITEM => VAL, ... ] );
+
+set|get_conf, set|get_program, _set|_get_build, _set|_get_source,
+_set|_get_mirror, _set|_get_fetch
+
+=back
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUS::Dist
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ACCESSORS
+
+parent(), status()
+
+=item STATUS ACCESSORS
+
+created(), installed(), uninstalled(), dist()
+
+=back
+
+=over 4
+
+=item $dist = CPANPLUS::Dist::YOUR_DIST_TYPE_HERE->new( module => MODOBJ );
+
+=back
+
+=over 4
+
+=item @dists = CPANPLUS::Dist->dist_types;
+
+=back
+
+=over 4
+
+=item $bool = CPANPLUS::Dist->rescan_dist_types;
+
+=back
+
+=over 4
+
+=item $bool = CPANPLUS::Dist->has_dist_type( $type )
+
+=back
+
+=over 4
+
+=item $bool = $dist->prereq_satisfied( modobj => $modobj, version =>
+$version_spec )
+
+=back
+
+=over 4
+
+=item $configure_requires = $dist->find_configure_requires( [file =>
+/path/to/META.yml] )
+
+=back
+
+=over 4
+
+=item $bool = $dist->_resolve_prereqs( ... )
+
+=back
+
+=head2 CPANPLUS::Dist::Autobundle
+
+=over 4
+
+=item SYNOPSIS
+
+=back
+
+=head2 CPANPLUS::Dist::Base - Base class for custom distribution classes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FLOW
+
+=item METHODS
+
+=back
+
+=over 4
+
+=item @subs = $Class->methods
+
+=back
+
+=over 4
+
+=item $bool = $Class->format_available
+
+=back
+
+=over 4
+
+=item $bool = $dist->init
+
+=back
+
+=over 4
+
+=item $bool = $dist->prepare
+
+=back
+
+=over 4
+
+=item $bool = $dist->create
+
+=back
+
+=over 4
+
+=item $bool = $dist->install
+
+=back
+
+=over 4
+
+=item $bool = $dist->uninstall
+
+=back
+
+=head2 CPANPLUS::Dist::Build - CPANPLUS plugin to install packages that use
+Build.PL
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ACCESSORS
+
+C<parent()>, C<status()>
+
+=item STATUS ACCESSORS
+
+C<build_pl ()>, C<build ()>, C<test ()>, C<prepared ()>, C<distdir ()>,
+C<created ()>, C<installed ()>, uninstalled (), C<_create_args ()>,
+C<_install_args ()>
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $bool = CPANPLUS::Dist::Build->format_available();
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $dist->init();
+
+=back
+
+=over 4
+
+=item $bool = $dist->prepare([perl => '/path/to/perl', buildflags =>
+'EXTRA=FLAGS', force => BOOL, verbose => BOOL])
+
+=back
+
+=over 4
+
+=item $dist->create([perl => '/path/to/perl', buildflags => 'EXTRA=FLAGS',
+prereq_target => TARGET, force => BOOL, verbose => BOOL, skiptest => BOOL])
+
+=back
+
+=over 4
+
+=item $dist->install([verbose => BOOL, perl => /path/to/perl])
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 CPANPLUS::Dist::Build::Constants - Constants for
+CPANPLUS::Dist::Build
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 CPANPLUS::Dist::MM
+
+=over 4
+
+=item SYNOPSIS
+
+=item ACCESSORS
+
+parent(), status()
+
+=item STATUS ACCESSORS
+
+makefile (), make (), test (), prepared (), distdir (), created (),
+installed (), uninstalled (), _create_args (), _install_args ()
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $bool = $dist->format_available();
+
+=back
+
+=back
+
+=over 4
+
+=item $href = $dist->_find_prereqs( file => '/path/to/Makefile', [verbose
+=> BOOL])
+
+=back
+
+=over 4
+
+=item $bool = $dist->create([perl => '/path/to/perl', make =>
+'/path/to/make', makeflags => 'EXTRA=FLAGS', prereq_target => TARGET,
+skiptest => BOOL, force => BOOL, verbose => BOOL])
+
+=back
+
+=over 4
+
+=item $bool = $dist->install([make => '/path/to/make', makemakerflags =>
+'EXTRA=FLAGS', force => BOOL, verbose => BOOL])
+
+=back
+
+=over 4
+
+=item $bool = $dist->write_makefile_pl([force => BOOL, verbose => BOOL])
+
+=back
+
+=head2 CPANPLUS::Dist::Sample -- Sample code to create your own Dist::*
+plugin
+
+=over 4
+
+=item Description.
+
+=back
+
+=head2 CPANPLUS::Error
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item cp_msg("message string" [,VERBOSE])
+
+=item msg()
+
+=item cp_error("error string" [,VERBOSE])
+
+=item error()
+
+=back
+
+=item CLASS METHODS
+
+=over 4
+
+=item CPANPLUS::Error->stack()
+
+=item CPANPLUS::Error->stack_as_string([TRACE])
+
+=item CPANPLUS::Error->flush()
+
+=back
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+$ERROR_FH, $MSG_FH
+
+=back
+
+=head2 CPANPLUS::FAQ
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 CPANPLUS::Hacking
+
+=over 4
+
+=item DESCRIPTION
+
+=item OBTAINING CPANPLUS
+
+=item INSTALLING CPANPLUS
+
+=item CONFIGURING CPANPLUS
+
+=item RUNNING CPANPLUS FROM DEVELOPMENT ENVIRONMENT
+
+=item RUNNING CPANPLUS TESTS
+
+=item FINDING BUGS
+
+Problem description, Program demonstrating the bug, [OPTIONAL] A patch to
+the test suite to test for the bug, [OPTIONAL] A patch to the code + tests
++ documentation
+
+=item SUPPLYING PATCHES
+
+In C<diff -u> or C<diff -c> format, From the root of the snapshot,
+Including patches for code + tests + docs, Sent per mail to
+cpanplus-devel@lists.sourceforge.net, With subject containing C<[PATCH]> +
+description of the patch
+
+=back
+
+=head2 CPANPLUS::Internals
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ACCESSORS
+
+_conf, _id
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $internals = CPANPLUS::Internals->_init( _conf => CONFIG_OBJ )
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $internals->_flush( list => \@caches )
+
+=back
+
+=over 4
+
+=item $bool = $internals->_register_callback( name => CALLBACK_NAME, code
+=> CODEREF );
+
+install_prerequisite, send_test_report, munge_test_report,
+edit_test_report, proceed_on_test_failure, munge_dist_metafile
+
+=back
+
+=over 4
+
+=item $bool = $internals->_add_to_includepath( directories => \@dirs )
+
+=back
+
+=over 4
+
+=item $id = CPANPLUS::Internals->_last_id
+
+=item $id = CPANPLUS::Internals->_store_id( $internals )
+
+=item $obj = CPANPLUS::Internals->_retrieve_id( $ID )
+
+=item CPANPLUS::Internals->_remove_id( $ID )
+
+=item @objs = CPANPLUS::Internals->_return_all_objects
+
+=back
+
+=head2 CPANPLUS::Internals::Extract
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item $dir = _extract( module => $modobj, [perl => '/path/to/perl',
+extractdir => '/path/to/extract/to', prefer_bin => BOOL, verbose => BOOL,
+force => BOOL] )
+
+module, extractdir, prefer_bin, perl, verbose, force
+
+=back
+
+=back
+
+=head2 CPANPLUS::Internals::Fetch
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=back
+
+=over 4
+
+=item $path = _fetch( module => $modobj, [fetchdir => '/path/to/save/to',
+fetch_from => 'scheme://path/to/fetch/from', verbose => BOOL, force =>
+BOOL, prefer_bin => BOOL, ttl => $seconds] )
+
+=back
+
+=over 4
+
+=item _add_fail_host( host => $host_hashref )
+
+=item _host_ok( host => $host_hashref )
+
+=back
+
+=head2 CPANPLUS::Internals::Report
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item $bool = $cb->_have_query_report_modules
+
+=item $bool = $cb->_have_send_report_modules
+
+=back
+
+=back
+
+=over 4
+
+=item @list = $cb->_query_report( module => $modobj, [all_versions => BOOL,
+verbose => BOOL] )
+
+=back
+
+=over 4
+
+=item $bool = $cb->_send_report( module => $modobj, buffer => $make_output,
+failed => BOOL, [save => BOOL, address => $email_to, verbose => BOOL, force
+=> BOOL]);
+
+module, buffer, failed, save, address, verbose, force
+
+=back
+
+=head2 CPANPLUS::Internals::Search
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item _search_module_tree( type => TYPE, allow => \@regexes, [data =>
+\@previous_results ] )
+
+type, allow, data
+
+=back
+
+=back
+
+=over 4
+
+=item _search_author_tree( type => TYPE, allow => \@regexex, [data =>
+\@previous_results ] )
+
+type, allow, data
+
+=back
+
+=over 4
+
+=item _all_installed()
+
+=back
+
+=head2 CPANPLUS::Internals::Source
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=back
+
+=over 4
+
+=item $cb->_build_trees( uptodate => BOOL, [use_stored => BOOL, path =>
+$path, verbose => BOOL] )
+
+uptodate, path, verbose, use_stored
+
+=back
+
+=over 4
+
+=item $cb->_check_trees( [update_source => BOOL, path => PATH, verbose =>
+BOOL] )
+
+update_source, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->__check_uptodate( file => $file, name => $name, [update_source
+=> BOOL, verbose => BOOL] )
+
+file, name, update_source, verbose
+
+=back
+
+=over 4
+
+=item $cb->_update_source( name => $name, [path => $path, verbose => BOOL]
+)
+
+name, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->__create_author_tree([path => $path, uptodate => BOOL, verbose
+=> BOOL])
+
+uptodate, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->_create_mod_tree([path => $path, uptodate => BOOL, verbose =>
+BOOL])
+
+uptodate, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->__create_dslip_tree([path => $path, uptodate => BOOL, verbose =>
+BOOL])
+
+uptodate, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->_dslip_defs ()
+
+=back
+
+=over 4
+
+=item $file = $cb->_add_custom_module_source( uri => URI, [verbose => BOOL]
+);
+
+=back
+
+=over 4
+
+=item $index = $cb->__custom_module_source_index_file( uri => $uri );
+
+=back
+
+=over 4
+
+=item $file = $cb->_remove_custom_module_source( uri => URI, [verbose =>
+BOOL] );
+
+=back
+
+=over 4
+
+=item %files = $cb->__list_custom_module_sources
+
+=back
+
+=over 4
+
+=item $bool = $cb->__update_custom_module_sources( [verbose => BOOL] );
+
+=back
+
+=over 4
+
+=item $ok = $cb->__update_custom_module_source
+
+=back
+
+=over 4
+
+=item $bool = $cb->__write_custom_module_index( path => /path/to/packages,
+[to => /path/to/index/file, verbose => BOOL] )
+
+=back
+
+=over 4
+
+=item $bool = $cb->__create_custom_module_entries( [verbose => BOOL] )
+
+=back
+
+=head2 CPANPLUS::Internals::Source::Memory - In memory implementation
+
+=over 4
+
+=item $cb->__memory_retrieve_source(name => $name, [path => $path, uptodate
+=> BOOL, verbose => BOOL])
+
+name, uptodate, path, verbose
+
+=back
+
+=over 4
+
+=item $cb->__memory_save_source([verbose => BOOL, path => $path])
+
+path, verbose
+
+=back
+
+=head2 CPANPLUS::Internals::Source::SQLite - SQLite implementation
+
+=head2 CPANPLUS::Internals::Utils
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item $cb->_mkdir( dir => '/some/dir' )
+
+=back
+
+=back
+
+=over 4
+
+=item $cb->_chdir( dir => '/some/dir' )
+
+=back
+
+=over 4
+
+=item $cb->_rmdir( dir => '/some/dir' );
+
+=back
+
+=over 4
+
+=item $cb->_perl_version ( perl => 'some/perl/binary' );
+
+=back
+
+=over 4
+
+=item $cb->_version_to_number( version => $version );
+
+=back
+
+=over 4
+
+=item $cb->_whoami
+
+=back
+
+=over 4
+
+=item _get_file_contents( file => $file );
+
+=back
+
+=over 4
+
+=item $cb->_mode_plus_w( file => '/path/to/file' );
+
+=back
+
+=over 4
+
+=item $uri = $cb->_host_to_uri( scheme => SCHEME, host => HOST, path =>
+PATH );
+
+=back
+
+=over 4
+
+=item $cb->_vcmp( VERSION, VERSION );
+
+=back
+
+=over 4
+
+=item $cb->_home_dir
+
+=back
+
+=over 4
+
+=item $path = $cb->_safe_path( path => $path );
+
+=back
+
+=over 4
+
+=item ($pkg, $version, $ext) = $cb->_split_package_string( package =>
+PACKAGE_STRING );
+
+=back
+
+=head2 CPANPLUS::Module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item CLASS METHODS
+
+=over 4
+
+=item accessors ()
+
+=back
+
+=back
+
+=over 4
+
+=item ACCESSORS
+
+name, module, version, path, comment, package, description, dslip
+
+=back
+
+status, author, parent
+
+=over 4
+
+=item STATUS ACCESSORS
+
+installer_type, dist_cpan, dist, prereqs | requires, configure_requires,
+signature, extract, fetch, readme, uninstall, created, installed,
+checksums, checksum_ok, checksum_value
+
+=item METHODS
+
+=over 4
+
+=item $self = CPANPLUS::Module->new( OPTIONS )
+
+=back
+
+=back
+
+=over 4
+
+=item $mod->package_name( [$package_string] )
+
+=item $mod->package_version( [$package_string] )
+
+=item $mod->package_extension( [$package_string] )
+
+=item $mod->package_is_perl_core
+
+=item $mod->module_is_supplied_with_perl_core( [version => $]] )
+
+=item $mod->is_bundle
+
+=item $mod->is_autobundle;
+
+=item $mod->is_third_party
+
+=item $mod->third_party_information
+
+=back
+
+=over 4
+
+=item $clone = $self->clone
+
+=back
+
+=over 4
+
+=item $where = $self->fetch
+
+=back
+
+=over 4
+
+=item $path = $self->extract
+
+=back
+
+=over 4
+
+=item $type = $self->get_installer_type([prefer_makefile => BOOL])
+
+=back
+
+=over 4
+
+=item $dist = $self->dist([target => 'prepare|create', format =>
+DISTRIBUTION_TYPE, args => {key => val}]);
+
+=back
+
+=over 4
+
+=item $bool = $mod->prepare( )
+
+Convenience method around C<install()> that prepares a module
+without actually building it. This is equivalent to invoking C<install>
+with C<target> set to C<prepare>
+
+=back
+
+=over 4
+
+=item $bool = $mod->create( )
+
+=back
+
+=over 4
+
+=item $bool = $mod->test( )
+
+=back
+
+=over 4
+
+=item $bool = $self->install([ target => 'init|prepare|create|install',
+format => FORMAT_TYPE, extractdir => DIRECTORY, fetchdir => DIRECTORY,
+prefer_bin => BOOL, force => BOOL, verbose => BOOL, ..... ]);
+
+=back
+
+=over 4
+
+=item $text = $self->readme
+
+=back
+
+=over 4
+
+=item $version = $self->installed_version()
+
+=item $where = $self->installed_file()
+
+=item $dir = $self->installed_dir()
+
+=item $bool = $self->is_uptodate([version => VERSION_NUMBER])
+
+=back
+
+=over 4
+
+=item $href = $self->details()
+
+=back
+
+=over 4
+
+=item @list = $self->contains()
+
+=back
+
+=over 4
+
+=item @list_of_hrefs = $self->fetch_report()
+
+=back
+
+=over 4
+
+=item $bool = $self->uninstall([type => [all|man|prog])
+
+=back
+
+=over 4
+
+=item @modobj = $self->distributions()
+
+=back
+
+=over 4
+
+=item @list = $self->files ()
+
+=item @list = $self->directory_tree ()
+
+=item @list = $self->packlist ()
+
+=item @list = $self->validate ()
+
+=back
+
+=over 4
+
+=item $bool = $self->add_to_includepath;
+
+=item $path = $self->best_path_to_module_build();
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 CPANPLUS::Module::Author
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ACCESSORS
+
+author, cpanid, email, parent
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $auth = CPANPLUS::Module::Author->new( author => AUTHOR_NAME, cpanid
+=> CPAN_ID, _id => INTERNALS_ID [, email => AUTHOR_EMAIL] )
+
+=back
+
+=back
+
+=over 4
+
+=item @mod_objs = $auth->modules()
+
+=back
+
+=over 4
+
+=item @dists = $auth->distributions()
+
+=back
+
+=over 4
+
+=item CLASS METHODS
+
+=over 4
+
+=item accessors ()
+
+=back
+
+=back
+
+=head2 CPANPLUS::Module::Author::Fake
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item new( _id => DIGIT )
+
+=back
+
+=back
+
+=head2 CPANPLUS::Module::Checksums
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item $mod->checksums
+
+=back
+
+=back
+
+=head2 CPANPLUS::Module::Fake
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item new( module => $mod, path => $path, package => $pkg, [_id => DIGIT] )
+
+=back
+
+=back
+
+=head2 CPANPLUSelfupdate, CPANPLUS::Selfupdate
+
+=over 4
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $self = CPANPLUS::Selfupdate->new( $backend_object );
+
+=back
+
+=back
+
+=over 4
+
+=item %list = $self->list_modules_to_update( update =>
+"core|dependencies|enabled_features|features|all", [latest => BOOL] )
+
+List which modules C<selfupdate> would upgrade. You can update either
+the core (CPANPLUS itself), the core dependencies, all features you have
+currently turned on, or all features available, or everything.
+
+=back
+
+=over 4
+
+=item @features = $self->list_features
+
+=back
+
+=over 4
+
+=item @features = $self->list_enabled_features
+
+=back
+
+=over 4
+
+=item @mods = $self->modules_for_feature( FEATURE [,AS_HASH] )
+
+=back
+
+=over 4
+
+=item @mods = $self->list_core_dependencies( [AS_HASH] )
+
+=back
+
+=over 4
+
+=item @mods = $self->list_core_modules( [AS_HASH] )
+
+=back
+
+=over 4
+
+=item CPANPLUS::Selfupdate::Module
+
+=back
+
+=over 4
+
+=item $version = $mod->version_required
+
+=back
+
+=over 4
+
+=item $bool = $mod->is_installed_version_sufficient
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 CPANPLUShell, CPANPLUS::Shell
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUShell::Classic, CPANPLUS::Shell::Classic - CPAN.pm emulation
+for CPANPLUS
+
+=over 4
+
+=item DESCRIPTION
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUShell::Default, CPANPLUS::Shell::Default
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUShell::Default::Plugins::CustomSource,
+CPANPLUS::Shell::Default::Plugins::CustomSource
+
+=over 4
+
+=item SYNOPSIS
+
+ ### elaborate help text
+ CPAN Terminal> /? cs
+
+=item DESCRIPTION
+
+=back
+
+=head2 CPANPLUShell::Default::Plugins::HOWTO,
+CPANPLUS::Shell::Default::Plugins::HOWTO -- documentation on how to write
+your own plugins
+
+=over 4
+
+=item SYNOPSIS
+
+=item HOWTO
+
+=over 4
+
+=item Registering Plugin Modules
+
+=item Registering Plugin Commands
+
+=item Registering Plugin Help
+
+=item Arguments to Plugin Commands
+
+Classname -- The name of your plugin class, Shell -- The
+CPANPLUS::Shell::Default object, Backend -- The CPANPLUS::Backend object,
+Command -- The command issued by the user, Input -- The input string
+from the user, Options -- A hashref of options provided by the user
+
+=back
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUShell::Default::Plugins::Remote,
+CPANPLUS::Shell::Default::Plugins::Remote
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANPLUShell::Default::Plugins::Source,
+CPANPLUS::Shell::Default::Plugins::Source
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 CPANox, CPAN::Nox - Wrapper around CPAN.pm without using any XS
+module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item LICENSE
+
+=item SEE ALSO
+
+=back
+
+=head2 Carp, carp - warn of errors (from perspective of caller)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Forcing a Stack Trace
+
+=back
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Carp::MaxEvalLen
+
+=item $Carp::MaxArgLen
+
+=item $Carp::MaxArgNums
+
+=item $Carp::Verbose
+
+=item @CARP_NOT
+
+=item %Carp::Internal
+
+=item %Carp::CarpInternal
+
+=item $Carp::CarpLevel
+
+=back
+
+=item BUGS
+
+=back
+
+=head2 Class::ISA - report the search path for a class's ISA tree
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+the function Class::ISA::super_path($CLASS), the function
+Class::ISA::self_and_super_path($CLASS), the function
+Class::ISA::self_and_super_versions($CLASS)
+
+=item CAUTIONARY NOTES
+
+=item COPYRIGHT AND LICENSE
+
+=item AUTHOR
+
+=item MAINTAINER
+
+=back
+
+=head2 Class::Struct - declare struct-like datatypes as Perl classes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item The C<struct()> function
+
+=item Class Creation at Compile Time
+
+=item Element Types and Accessor Methods
+
+Scalar (C<'$'> or C<'*$'>), Array (C<'@'> or C<'*@'>), Hash (C<'%'> or
+C<'*%'>), Class (C<'Class_Name'> or C<'*Class_Name'>)
+
+=item Initializing with C<new>
+
+=back
+
+=item EXAMPLES
+
+Example 1, Example 2, Example 3
+
+=item Author and Modification History
+
+=back
+
+=head2 Compress::Raw::Bzip2 - Low-Level Interface to bzip2 compression
+library
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Compression
+
+=over 4
+
+=item ($z, $status) = new Compress::Raw::Bzip2 $appendOutput,
+$blockSize100k, $workfactor;
+
+B<$appendOutput>, B<$blockSize100k>, B<$workfactor>
+
+=item $status = $bz->bzdeflate($input, $output);
+
+=item $status = $bz->bzflush($output);
+
+=item $status = $bz->bzclose($output);
+
+=item Example
+
+=back
+
+=item Uncompression
+
+=over 4
+
+=item ($z, $status) = new Compress::Raw::Bunzip2 $appendOutput,
+$consumeInput, $small, $limitOutput;
+
+B<$appendOutput>, B<$consumeInput>, B<$small>, B<$limitOutput>
+
+=item $status = $z->bzinflate($input, $output);
+
+=back
+
+=item Misc
+
+=over 4
+
+=item my $version = Compress::Raw::Bzip2::bzlibversion();
+
+=back
+
+=item Constants
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Compress::Raw::Zlib - Low-Level Interface to zlib compression
+library
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Compress::Raw::Zlib::Deflate
+
+=over 4
+
+=item B<($d, $status) = new Compress::Raw::Zlib::Deflate( [OPT] ) >
+
+B<-Level>, B<-Method>, B<-WindowBits>, B<-MemLevel>, B<-Strategy>,
+B<-Dictionary>, B<-Bufsize>, B<-AppendOutput>, B<-CRC32>, B<-ADLER32>
+
+=item B<$status = $d-E<gt>deflate($input, $output)>
+
+=item B<$status = $d-E<gt>flush($output [, $flush_type]) >
+
+=item B<$status = $d-E<gt>deflateReset() >
+
+=item B<$status = $d-E<gt>deflateParams([OPT])>
+
+B<-Level>, B<-Strategy>, B<-BufSize>
+
+=item B<$status = $d-E<gt>deflateTune($good_length, $max_lazy,
+$nice_length, $max_chain)>
+
+=item B<$d-E<gt>dict_adler()>
+
+=item B<$d-E<gt>crc32()>
+
+=item B<$d-E<gt>adler32()>
+
+=item B<$d-E<gt>msg()>
+
+=item B<$d-E<gt>total_in()>
+
+=item B<$d-E<gt>total_out()>
+
+=item B<$d-E<gt>get_Strategy()>
+
+=item B<$d-E<gt>get_Level()>
+
+=item B<$d-E<gt>get_BufSize()>
+
+=item Example
+
+=back
+
+=item Compress::Raw::Zlib::Inflate
+
+=over 4
+
+=item B< ($i, $status) = new Compress::Raw::Zlib::Inflate( [OPT] ) >
+
+B<-WindowBits>, B<-Bufsize>, B<-Dictionary>, B<-AppendOutput>, B<-CRC32>,
+B<-ADLER32>, B<-ConsumeInput>, B<-LimitOutput>
+
+=item B< $status = $i-E<gt>inflate($input, $output [,$eof]) >
+
+=item B<$status = $i-E<gt>inflateSync($input)>
+
+=item B<$i-E<gt>dict_adler()>
+
+=item B<$i-E<gt>crc32()>
+
+=item B<$i-E<gt>adler32()>
+
+=item B<$i-E<gt>msg()>
+
+=item B<$i-E<gt>total_in()>
+
+=item B<$i-E<gt>total_out()>
+
+=item B<$d-E<gt>get_BufSize()>
+
+=item Examples
+
+=back
+
+=item CHECKSUM FUNCTIONS
+
+=item Misc
+
+=over 4
+
+=item my $version = Compress::Raw::Zlib::zlib_version();
+
+=back
+
+=item The LimitOutput option.
+
+=item ACCESSING ZIP FILES
+
+=item CONSTANTS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Compress::Zlib - Interface to zlib compression library
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Notes for users of Compress::Zlib version 1
+
+=back
+
+=item GZIP INTERFACE
+
+B<$gz = gzopen($filename, $mode)>, B<$gz = gzopen($filehandle, $mode)>,
+B<$bytesread = $gz-E<gt>gzread($buffer [, $size]) ;>, B<$bytesread =
+$gz-E<gt>gzreadline($line) ;>, B<$byteswritten = $gz-E<gt>gzwrite($buffer)
+;>, B<$status = $gz-E<gt>gzflush($flush_type) ;>, B<$offset =
+$gz-E<gt>gztell() ;>, B<$status = $gz-E<gt>gzseek($offset, $whence) ;>,
+B<$gz-E<gt>gzclose>, B<$gz-E<gt>gzsetparams($level, $strategy>, B<$level>,
+B<$strategy>, B<$gz-E<gt>gzerror>, B<$gzerrno>
+
+=over 4
+
+=item Examples
+
+=item Compress::Zlib::memGzip
+
+=item Compress::Zlib::memGunzip
+
+=back
+
+=item COMPRESS/UNCOMPRESS
+
+B<$dest = compress($source [, $level] ) ;>, B<$dest = uncompress($source)
+;>
+
+=item Deflate Interface
+
+=over 4
+
+=item B<($d, $status) = deflateInit( [OPT] )>
+
+B<-Level>, B<-Method>, B<-WindowBits>, B<-MemLevel>, B<-Strategy>,
+B<-Dictionary>, B<-Bufsize>
+
+=item B<($out, $status) = $d-E<gt>deflate($buffer)>
+
+=item B<($out, $status) = $d-E<gt>flush()>
+=head2 B<($out, $status) = $d-E<gt>flush($flush_type)>
+
+=item B<$status = $d-E<gt>deflateParams([OPT])>
+
+B<-Level>, B<-Strategy>
+
+=item B<$d-E<gt>dict_adler()>
+
+=item B<$d-E<gt>msg()>
+
+=item B<$d-E<gt>total_in()>
+
+=item B<$d-E<gt>total_out()>
+
+=item Example
+
+=back
+
+=item Inflate Interface
+
+=over 4
+
+=item B<($i, $status) = inflateInit()>
+
+B<-WindowBits>, B<-Bufsize>, B<-Dictionary>
+
+=item B<($out, $status) = $i-E<gt>inflate($buffer)>
+
+=item B<$status = $i-E<gt>inflateSync($buffer)>
+
+=item B<$i-E<gt>dict_adler()>
+
+=item B<$i-E<gt>msg()>
+
+=item B<$i-E<gt>total_in()>
+
+=item B<$i-E<gt>total_out()>
+
+=item Example
+
+=back
+
+=item CHECKSUM FUNCTIONS
+
+=item Misc
+
+=over 4
+
+=item my $version = Compress::Zlib::zlib_version();
+
+=back
+
+=item CONSTANTS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Config - access Perl configuration information
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+myconfig(), config_sh(), config_re($regex), config_vars(@names)
+
+=item EXAMPLE
+
+=item WARNING
+
+=item GLOSSARY
+
+=back
+
+=over 4
+
+=item _
+
+=back
+
+C<_a>, C<_exe>, C<_o>
+
+=over 4
+
+=item a
+
+=back
+
+C<afs>, C<afsroot>, C<alignbytes>, C<ansi2knr>, C<aphostname>,
+C<api_revision>, C<api_subversion>, C<api_version>, C<api_versionstring>,
+C<ar>, C<archlib>, C<archlibexp>, C<archname>, C<archname64>, C<archobjs>,
+C<asctime_r_proto>, C<awk>
+
+=over 4
+
+=item b
+
+=back
+
+C<baserev>, C<bash>, C<bin>, C<bin_ELF>, C<binexp>, C<bison>, C<byacc>,
+C<byteorder>
+
+=over 4
+
+=item c
+
+=back
+
+C<c>, C<castflags>, C<cat>, C<cc>, C<cccdlflags>, C<ccdlflags>, C<ccflags>,
+C<ccflags_uselargefiles>, C<ccname>, C<ccsymbols>, C<ccversion>, C<cf_by>,
+C<cf_email>, C<cf_time>, C<charbits>, C<charsize>, C<chgrp>, C<chmod>,
+C<chown>, C<clocktype>, C<comm>, C<compress>, C<config_arg0>,
+C<config_argc>, C<config_args>, C<contains>, C<cp>, C<cpio>, C<cpp>,
+C<cpp_stuff>, C<cppccsymbols>, C<cppflags>, C<cpplast>, C<cppminus>,
+C<cpprun>, C<cppstdin>, C<cppsymbols>, C<crypt_r_proto>, C<cryptlib>,
+C<csh>, C<ctermid_r_proto>, C<ctime_r_proto>
+
+=over 4
+
+=item d
+
+=back
+
+C<d__fwalk>, C<d_access>, C<d_accessx>, C<d_aintl>, C<d_alarm>,
+C<d_archlib>, C<d_asctime64>, C<d_asctime_r>, C<d_atolf>, C<d_atoll>,
+C<d_attribute_deprecated>, C<d_attribute_format>, C<d_attribute_malloc>,
+C<d_attribute_nonnull>, C<d_attribute_noreturn>, C<d_attribute_pure>,
+C<d_attribute_unused>, C<d_attribute_warn_unused_result>, C<d_bcmp>,
+C<d_bcopy>, C<d_bsd>, C<d_bsdgetpgrp>, C<d_bsdsetpgrp>,
+C<d_builtin_choose_expr>, C<d_builtin_expect>, C<d_bzero>,
+C<d_c99_variadic_macros>, C<d_casti32>, C<d_castneg>, C<d_charvspr>,
+C<d_chown>, C<d_chroot>, C<d_chsize>, C<d_class>, C<d_clearenv>,
+C<d_closedir>, C<d_cmsghdr_s>, C<d_const>, C<d_copysignl>, C<d_cplusplus>,
+C<d_crypt>, C<d_crypt_r>, C<d_csh>, C<d_ctermid>, C<d_ctermid_r>,
+C<d_ctime64>, C<d_ctime_r>, C<d_cuserid>, C<d_dbl_dig>, C<d_dbminitproto>,
+C<d_difftime>, C<d_difftime64>, C<d_dir_dd_fd>, C<d_dirfd>, C<d_dirnamlen>,
+C<d_dlerror>, C<d_dlopen>, C<d_dlsymun>, C<d_dosuid>, C<d_drand48_r>,
+C<d_drand48proto>, C<d_dup2>, C<d_eaccess>, C<d_endgrent>, C<d_endgrent_r>,
+C<d_endhent>, C<d_endhostent_r>, C<d_endnent>, C<d_endnetent_r>,
+C<d_endpent>, C<d_endprotoent_r>, C<d_endpwent>, C<d_endpwent_r>,
+C<d_endsent>, C<d_endservent_r>, C<d_eofnblk>, C<d_eunice>, C<d_faststdio>,
+C<d_fchdir>, C<d_fchmod>, C<d_fchown>, C<d_fcntl>, C<d_fcntl_can_lock>,
+C<d_fd_macros>, C<d_fd_set>, C<d_fds_bits>, C<d_fgetpos>, C<d_finite>,
+C<d_finitel>, C<d_flexfnam>, C<d_flock>, C<d_flockproto>, C<d_fork>,
+C<d_fp_class>, C<d_fpathconf>, C<d_fpclass>, C<d_fpclassify>,
+C<d_fpclassl>, C<d_fpos64_t>, C<d_frexpl>, C<d_fs_data_s>, C<d_fseeko>,
+C<d_fsetpos>, C<d_fstatfs>, C<d_fstatvfs>, C<d_fsync>, C<d_ftello>,
+C<d_ftime>, C<d_futimes>, C<d_Gconvert>, C<d_gdbm_ndbm_h_uses_prototypes>,
+C<d_gdbmndbm_h_uses_prototypes>, C<d_getaddrinfo>, C<d_getcwd>,
+C<d_getespwnam>, C<d_getfsstat>, C<d_getgrent>, C<d_getgrent_r>,
+C<d_getgrgid_r>, C<d_getgrnam_r>, C<d_getgrps>, C<d_gethbyaddr>,
+C<d_gethbyname>, C<d_gethent>, C<d_gethname>, C<d_gethostbyaddr_r>,
+C<d_gethostbyname_r>, C<d_gethostent_r>, C<d_gethostprotos>,
+C<d_getitimer>, C<d_getlogin>, C<d_getlogin_r>, C<d_getmnt>,
+C<d_getmntent>, C<d_getnameinfo>, C<d_getnbyaddr>, C<d_getnbyname>,
+C<d_getnent>, C<d_getnetbyaddr_r>, C<d_getnetbyname_r>, C<d_getnetent_r>,
+C<d_getnetprotos>, C<d_getpagsz>, C<d_getpbyname>, C<d_getpbynumber>,
+C<d_getpent>, C<d_getpgid>, C<d_getpgrp>, C<d_getpgrp2>, C<d_getppid>,
+C<d_getprior>, C<d_getprotobyname_r>, C<d_getprotobynumber_r>,
+C<d_getprotoent_r>, C<d_getprotoprotos>, C<d_getprpwnam>, C<d_getpwent>,
+C<d_getpwent_r>, C<d_getpwnam_r>, C<d_getpwuid_r>, C<d_getsbyname>,
+C<d_getsbyport>, C<d_getsent>, C<d_getservbyname_r>, C<d_getservbyport_r>,
+C<d_getservent_r>, C<d_getservprotos>, C<d_getspnam>, C<d_getspnam_r>,
+C<d_gettimeod>, C<d_gmtime64>, C<d_gmtime_r>, C<d_gnulibc>, C<d_grpasswd>,
+C<d_hasmntopt>, C<d_htonl>, C<d_ilogbl>, C<d_inc_version_list>, C<d_index>,
+C<d_inetaton>, C<d_inetntop>, C<d_inetpton>, C<d_int64_t>, C<d_isascii>,
+C<d_isfinite>, C<d_isinf>, C<d_isnan>, C<d_isnanl>, C<d_killpg>,
+C<d_lchown>, C<d_ldbl_dig>, C<d_libm_lib_version>, C<d_link>,
+C<d_localtime64>, C<d_localtime_r>, C<d_localtime_r_needs_tzset>,
+C<d_locconv>, C<d_lockf>, C<d_longdbl>, C<d_longlong>, C<d_lseekproto>,
+C<d_lstat>, C<d_madvise>, C<d_malloc_good_size>, C<d_malloc_size>,
+C<d_mblen>, C<d_mbstowcs>, C<d_mbtowc>, C<d_memchr>, C<d_memcmp>,
+C<d_memcpy>, C<d_memmove>, C<d_memset>, C<d_mkdir>, C<d_mkdtemp>,
+C<d_mkfifo>, C<d_mkstemp>, C<d_mkstemps>, C<d_mktime>, C<d_mktime64>,
+C<d_mmap>, C<d_modfl>, C<d_modfl_pow32_bug>, C<d_modflproto>,
+C<d_mprotect>, C<d_msg>, C<d_msg_ctrunc>, C<d_msg_dontroute>, C<d_msg_oob>,
+C<d_msg_peek>, C<d_msg_proxy>, C<d_msgctl>, C<d_msgget>, C<d_msghdr_s>,
+C<d_msgrcv>, C<d_msgsnd>, C<d_msync>, C<d_munmap>, C<d_mymalloc>,
+C<d_ndbm>, C<d_ndbm_h_uses_prototypes>, C<d_nice>, C<d_nl_langinfo>,
+C<d_nv_preserves_uv>, C<d_nv_zero_is_allbits_zero>, C<d_off64_t>,
+C<d_old_pthread_create_joinable>, C<d_oldpthreads>, C<d_oldsock>,
+C<d_open3>, C<d_pathconf>, C<d_pause>, C<d_perl_otherlibdirs>,
+C<d_phostname>, C<d_pipe>, C<d_poll>, C<d_portable>, C<d_PRId64>,
+C<d_PRIeldbl>, C<d_PRIEUldbl>, C<d_PRIfldbl>, C<d_PRIFUldbl>,
+C<d_PRIgldbl>, C<d_PRIGUldbl>, C<d_PRIi64>, C<d_printf_format_null>,
+C<d_PRIo64>, C<d_PRIu64>, C<d_PRIx64>, C<d_PRIXU64>, C<d_procselfexe>,
+C<d_pseudofork>, C<d_pthread_atfork>, C<d_pthread_attr_setscope>,
+C<d_pthread_yield>, C<d_pwage>, C<d_pwchange>, C<d_pwclass>,
+C<d_pwcomment>, C<d_pwexpire>, C<d_pwgecos>, C<d_pwpasswd>, C<d_pwquota>,
+C<d_qgcvt>, C<d_quad>, C<d_random_r>, C<d_readdir>, C<d_readdir64_r>,
+C<d_readdir_r>, C<d_readlink>, C<d_readv>, C<d_recvmsg>, C<d_rename>,
+C<d_rewinddir>, C<d_rmdir>, C<d_safebcpy>, C<d_safemcpy>, C<d_sanemcmp>,
+C<d_sbrkproto>, C<d_scalbnl>, C<d_sched_yield>, C<d_scm_rights>,
+C<d_SCNfldbl>, C<d_seekdir>, C<d_select>, C<d_sem>, C<d_semctl>,
+C<d_semctl_semid_ds>, C<d_semctl_semun>, C<d_semget>, C<d_semop>,
+C<d_sendmsg>, C<d_setegid>, C<d_seteuid>, C<d_setgrent>, C<d_setgrent_r>,
+C<d_setgrps>, C<d_sethent>, C<d_sethostent_r>, C<d_setitimer>,
+C<d_setlinebuf>, C<d_setlocale>, C<d_setlocale_r>, C<d_setnent>,
+C<d_setnetent_r>, C<d_setpent>, C<d_setpgid>, C<d_setpgrp>, C<d_setpgrp2>,
+C<d_setprior>, C<d_setproctitle>, C<d_setprotoent_r>, C<d_setpwent>,
+C<d_setpwent_r>, C<d_setregid>, C<d_setresgid>, C<d_setresuid>,
+C<d_setreuid>, C<d_setrgid>, C<d_setruid>, C<d_setsent>, C<d_setservent_r>,
+C<d_setsid>, C<d_setvbuf>, C<d_sfio>, C<d_shm>, C<d_shmat>,
+C<d_shmatprototype>, C<d_shmctl>, C<d_shmdt>, C<d_shmget>, C<d_sigaction>,
+C<d_signbit>, C<d_sigprocmask>, C<d_sigsetjmp>, C<d_sitearch>,
+C<d_snprintf>, C<d_sockatmark>, C<d_sockatmarkproto>, C<d_socket>,
+C<d_socklen_t>, C<d_sockpair>, C<d_socks5_init>,
+C<d_sprintf_returns_strlen>, C<d_sqrtl>, C<d_srand48_r>, C<d_srandom_r>,
+C<d_sresgproto>, C<d_sresuproto>, C<d_statblks>, C<d_statfs_f_flags>,
+C<d_statfs_s>, C<d_statvfs>, C<d_stdio_cnt_lval>, C<d_stdio_ptr_lval>,
+C<d_stdio_ptr_lval_nochange_cnt>, C<d_stdio_ptr_lval_sets_cnt>,
+C<d_stdio_stream_array>, C<d_stdiobase>, C<d_stdstdio>, C<d_strchr>,
+C<d_strcoll>, C<d_strctcpy>, C<d_strerrm>, C<d_strerror>, C<d_strerror_r>,
+C<d_strftime>, C<d_strlcat>, C<d_strlcpy>, C<d_strtod>, C<d_strtol>,
+C<d_strtold>, C<d_strtoll>, C<d_strtoq>, C<d_strtoul>, C<d_strtoull>,
+C<d_strtouq>, C<d_strxfrm>, C<d_suidsafe>, C<d_symlink>, C<d_syscall>,
+C<d_syscallproto>, C<d_sysconf>, C<d_sysernlst>, C<d_syserrlst>,
+C<d_system>, C<d_tcgetpgrp>, C<d_tcsetpgrp>, C<d_telldir>,
+C<d_telldirproto>, C<d_time>, C<d_timegm>, C<d_times>, C<d_tm_tm_gmtoff>,
+C<d_tm_tm_zone>, C<d_tmpnam_r>, C<d_truncate>, C<d_ttyname_r>, C<d_tzname>,
+C<d_u32align>, C<d_ualarm>, C<d_umask>, C<d_uname>, C<d_union_semun>,
+C<d_unordered>, C<d_unsetenv>, C<d_usleep>, C<d_usleepproto>, C<d_ustat>,
+C<d_vendorarch>, C<d_vendorbin>, C<d_vendorlib>, C<d_vendorscript>,
+C<d_vfork>, C<d_void_closedir>, C<d_voidsig>, C<d_voidtty>, C<d_volatile>,
+C<d_vprintf>, C<d_vsnprintf>, C<d_wait4>, C<d_waitpid>, C<d_wcstombs>,
+C<d_wctomb>, C<d_writev>, C<d_xenix>, C<date>, C<db_hashtype>,
+C<db_prefixtype>, C<db_version_major>, C<db_version_minor>,
+C<db_version_patch>, C<defvoidused>, C<direntrytype>, C<dlext>, C<dlsrc>,
+C<doublesize>, C<drand01>, C<drand48_r_proto>, C<dtrace>, C<dynamic_ext>
+
+=over 4
+
+=item e
+
+=back
+
+C<eagain>, C<ebcdic>, C<echo>, C<egrep>, C<emacs>, C<endgrent_r_proto>,
+C<endhostent_r_proto>, C<endnetent_r_proto>, C<endprotoent_r_proto>,
+C<endpwent_r_proto>, C<endservent_r_proto>, C<eunicefix>, C<exe_ext>,
+C<expr>, C<extensions>, C<extern_C>, C<extras>
+
+=over 4
+
+=item f
+
+=back
+
+C<fflushall>, C<fflushNULL>, C<find>, C<firstmakefile>, C<flex>,
+C<fpossize>, C<fpostype>, C<freetype>, C<from>, C<full_ar>, C<full_csh>,
+C<full_sed>
+
+=over 4
+
+=item g
+
+=back
+
+C<gccansipedantic>, C<gccosandvers>, C<gccversion>, C<getgrent_r_proto>,
+C<getgrgid_r_proto>, C<getgrnam_r_proto>, C<gethostbyaddr_r_proto>,
+C<gethostbyname_r_proto>, C<gethostent_r_proto>, C<getlogin_r_proto>,
+C<getnetbyaddr_r_proto>, C<getnetbyname_r_proto>, C<getnetent_r_proto>,
+C<getprotobyname_r_proto>, C<getprotobynumber_r_proto>,
+C<getprotoent_r_proto>, C<getpwent_r_proto>, C<getpwnam_r_proto>,
+C<getpwuid_r_proto>, C<getservbyname_r_proto>, C<getservbyport_r_proto>,
+C<getservent_r_proto>, C<getspnam_r_proto>, C<gidformat>, C<gidsign>,
+C<gidsize>, C<gidtype>, C<glibpth>, C<gmake>, C<gmtime_r_proto>,
+C<gnulibc_version>, C<grep>, C<groupcat>, C<groupstype>, C<gzip>
+
+=over 4
+
+=item h
+
+=back
+
+C<h_fcntl>, C<h_sysfile>, C<hint>, C<hostcat>, C<html1dir>, C<html1direxp>,
+C<html3dir>, C<html3direxp>
+
+=over 4
+
+=item i
+
+=back
+
+C<i16size>, C<i16type>, C<i32size>, C<i32type>, C<i64size>, C<i64type>,
+C<i8size>, C<i8type>, C<i_arpainet>, C<i_assert>, C<i_bsdioctl>,
+C<i_crypt>, C<i_db>, C<i_dbm>, C<i_dirent>, C<i_dld>, C<i_dlfcn>,
+C<i_fcntl>, C<i_float>, C<i_fp>, C<i_fp_class>, C<i_gdbm>, C<i_gdbm_ndbm>,
+C<i_gdbmndbm>, C<i_grp>, C<i_ieeefp>, C<i_inttypes>, C<i_langinfo>,
+C<i_libutil>, C<i_limits>, C<i_locale>, C<i_machcthr>, C<i_malloc>,
+C<i_mallocmalloc>, C<i_math>, C<i_memory>, C<i_mntent>, C<i_ndbm>,
+C<i_netdb>, C<i_neterrno>, C<i_netinettcp>, C<i_niin>, C<i_poll>,
+C<i_prot>, C<i_pthread>, C<i_pwd>, C<i_rpcsvcdbm>, C<i_sfio>, C<i_sgtty>,
+C<i_shadow>, C<i_socks>, C<i_stdarg>, C<i_stddef>, C<i_stdlib>,
+C<i_string>, C<i_sunmath>, C<i_sysaccess>, C<i_sysdir>, C<i_sysfile>,
+C<i_sysfilio>, C<i_sysin>, C<i_sysioctl>, C<i_syslog>, C<i_sysmman>,
+C<i_sysmode>, C<i_sysmount>, C<i_sysndir>, C<i_sysparam>, C<i_syspoll>,
+C<i_sysresrc>, C<i_syssecrt>, C<i_sysselct>, C<i_syssockio>, C<i_sysstat>,
+C<i_sysstatfs>, C<i_sysstatvfs>, C<i_systime>, C<i_systimek>,
+C<i_systimes>, C<i_systypes>, C<i_sysuio>, C<i_sysun>, C<i_sysutsname>,
+C<i_sysvfs>, C<i_syswait>, C<i_termio>, C<i_termios>, C<i_time>,
+C<i_unistd>, C<i_ustat>, C<i_utime>, C<i_values>, C<i_varargs>,
+C<i_varhdr>, C<i_vfork>, C<ignore_versioned_solibs>, C<inc_version_list>,
+C<inc_version_list_init>, C<incpath>, C<inews>, C<initialinstalllocation>,
+C<installarchlib>, C<installbin>, C<installhtml1dir>, C<installhtml3dir>,
+C<installman1dir>, C<installman3dir>, C<installprefix>,
+C<installprefixexp>, C<installprivlib>, C<installscript>,
+C<installsitearch>, C<installsitebin>, C<installsitehtml1dir>,
+C<installsitehtml3dir>, C<installsitelib>, C<installsiteman1dir>,
+C<installsiteman3dir>, C<installsitescript>, C<installstyle>,
+C<installusrbinperl>, C<installvendorarch>, C<installvendorbin>,
+C<installvendorhtml1dir>, C<installvendorhtml3dir>, C<installvendorlib>,
+C<installvendorman1dir>, C<installvendorman3dir>, C<installvendorscript>,
+C<intsize>, C<issymlink>, C<ivdformat>, C<ivsize>, C<ivtype>
+
+=over 4
+
+=item k
+
+=back
+
+C<known_extensions>, C<ksh>
+
+=over 4
+
+=item l
+
+=back
+
+C<ld>, C<lddlflags>, C<ldflags>, C<ldflags_uselargefiles>, C<ldlibpthname>,
+C<less>, C<lib_ext>, C<libc>, C<libperl>, C<libpth>, C<libs>, C<libsdirs>,
+C<libsfiles>, C<libsfound>, C<libspath>, C<libswanted>,
+C<libswanted_uselargefiles>, C<line>, C<lint>, C<lkflags>, C<ln>, C<lns>,
+C<localtime_r_proto>, C<locincpth>, C<loclibpth>, C<longdblsize>,
+C<longlongsize>, C<longsize>, C<lp>, C<lpr>, C<ls>, C<lseeksize>,
+C<lseektype>
+
+=over 4
+
+=item m
+
+=back
+
+C<mad>, C<madlyh>, C<madlyobj>, C<madlysrc>, C<mail>, C<mailx>, C<make>,
+C<make_set_make>, C<mallocobj>, C<mallocsrc>, C<malloctype>, C<man1dir>,
+C<man1direxp>, C<man1ext>, C<man3dir>, C<man3direxp>, C<man3ext>,
+C<mips_type>, C<mistrustnm>, C<mkdir>, C<mmaptype>, C<modetype>, C<more>,
+C<multiarch>, C<mv>, C<myarchname>, C<mydomain>, C<myhostname>, C<myuname>
+
+=over 4
+
+=item n
+
+=back
+
+C<n>, C<need_va_copy>, C<netdb_hlen_type>, C<netdb_host_type>,
+C<netdb_name_type>, C<netdb_net_type>, C<nm>, C<nm_opt>, C<nm_so_opt>,
+C<nonxs_ext>, C<nroff>, C<nv_overflows_integers_at>,
+C<nv_preserves_uv_bits>, C<nveformat>, C<nvEUformat>, C<nvfformat>,
+C<nvFUformat>, C<nvgformat>, C<nvGUformat>, C<nvsize>, C<nvtype>
+
+=over 4
+
+=item o
+
+=back
+
+C<o_nonblock>, C<obj_ext>, C<old_pthread_create_joinable>, C<optimize>,
+C<orderlib>, C<osname>, C<osvers>, C<otherlibdirs>
+
+=over 4
+
+=item p
+
+=back
+
+C<package>, C<pager>, C<passcat>, C<patchlevel>, C<path_sep>, C<perl>,
+C<perl5>
+
+=over 4
+
+=item P
+
+=back
+
+C<PERL_API_REVISION>, C<PERL_API_SUBVERSION>, C<PERL_API_VERSION>,
+C<PERL_CONFIG_SH>, C<PERL_PATCHLEVEL>, C<perl_patchlevel>,
+C<PERL_REVISION>, C<PERL_SUBVERSION>, C<PERL_VERSION>, C<perladmin>,
+C<perllibs>, C<perlpath>, C<pg>, C<phostname>, C<pidtype>, C<plibpth>,
+C<pmake>, C<pr>, C<prefix>, C<prefixexp>, C<privlib>, C<privlibexp>,
+C<procselfexe>, C<prototype>, C<ptrsize>
+
+=over 4
+
+=item q
+
+=back
+
+C<quadkind>, C<quadtype>
+
+=over 4
+
+=item r
+
+=back
+
+C<randbits>, C<randfunc>, C<random_r_proto>, C<randseedtype>, C<ranlib>,
+C<rd_nodata>, C<readdir64_r_proto>, C<readdir_r_proto>, C<revision>, C<rm>,
+C<rm_try>, C<rmail>, C<run>, C<runnm>
+
+=over 4
+
+=item s
+
+=back
+
+C<sched_yield>, C<scriptdir>, C<scriptdirexp>, C<sed>, C<seedfunc>,
+C<selectminbits>, C<selecttype>, C<sendmail>, C<setgrent_r_proto>,
+C<sethostent_r_proto>, C<setlocale_r_proto>, C<setnetent_r_proto>,
+C<setprotoent_r_proto>, C<setpwent_r_proto>, C<setservent_r_proto>,
+C<sGMTIME_max>, C<sGMTIME_min>, C<sh>, C<shar>, C<sharpbang>, C<shmattype>,
+C<shortsize>, C<shrpenv>, C<shsharp>, C<sig_count>, C<sig_name>,
+C<sig_name_init>, C<sig_num>, C<sig_num_init>, C<sig_size>, C<signal_t>,
+C<sitearch>, C<sitearchexp>, C<sitebin>, C<sitebinexp>, C<sitehtml1dir>,
+C<sitehtml1direxp>, C<sitehtml3dir>, C<sitehtml3direxp>, C<sitelib>,
+C<sitelib_stem>, C<sitelibexp>, C<siteman1dir>, C<siteman1direxp>,
+C<siteman3dir>, C<siteman3direxp>, C<siteprefix>, C<siteprefixexp>,
+C<sitescript>, C<sitescriptexp>, C<sizesize>, C<sizetype>, C<sleep>,
+C<sLOCALTIME_max>, C<sLOCALTIME_min>, C<smail>, C<so>, C<sockethdr>,
+C<socketlib>, C<socksizetype>, C<sort>, C<spackage>, C<spitshell>,
+C<sPRId64>, C<sPRIeldbl>, C<sPRIEUldbl>, C<sPRIfldbl>, C<sPRIFUldbl>,
+C<sPRIgldbl>, C<sPRIGUldbl>, C<sPRIi64>, C<sPRIo64>, C<sPRIu64>,
+C<sPRIx64>, C<sPRIXU64>, C<srand48_r_proto>, C<srandom_r_proto>, C<src>,
+C<sSCNfldbl>, C<ssizetype>, C<startperl>, C<startsh>, C<static_ext>,
+C<stdchar>, C<stdio_base>, C<stdio_bufsiz>, C<stdio_cnt>, C<stdio_filbuf>,
+C<stdio_ptr>, C<stdio_stream_array>, C<strerror_r_proto>, C<strings>,
+C<submit>, C<subversion>, C<sysman>
+
+=over 4
+
+=item t
+
+=back
+
+C<tail>, C<tar>, C<targetarch>, C<tbl>, C<tee>, C<test>, C<timeincl>,
+C<timetype>, C<tmpnam_r_proto>, C<to>, C<touch>, C<tr>, C<trnl>, C<troff>,
+C<ttyname_r_proto>
+
+=over 4
+
+=item u
+
+=back
+
+C<u16size>, C<u16type>, C<u32size>, C<u32type>, C<u64size>, C<u64type>,
+C<u8size>, C<u8type>, C<uidformat>, C<uidsign>, C<uidsize>, C<uidtype>,
+C<uname>, C<uniq>, C<uquadtype>, C<use5005threads>, C<use64bitall>,
+C<use64bitint>, C<usecrosscompile>, C<usedevel>, C<usedl>, C<usedtrace>,
+C<usefaststdio>, C<useithreads>, C<uselargefiles>, C<uselongdouble>,
+C<usemallocwrap>, C<usemorebits>, C<usemultiplicity>, C<usemymalloc>,
+C<usenm>, C<useopcode>, C<useperlio>, C<useposix>, C<usereentrant>,
+C<userelocatableinc>, C<usesfio>, C<useshrplib>, C<usesitecustomize>,
+C<usesocks>, C<usethreads>, C<usevendorprefix>, C<usevfork>, C<usrinc>,
+C<uuname>, C<uvoformat>, C<uvsize>, C<uvtype>, C<uvuformat>, C<uvxformat>,
+C<uvXUformat>
+
+=over 4
+
+=item v
+
+=back
+
+C<vaproto>, C<vendorarch>, C<vendorarchexp>, C<vendorbin>, C<vendorbinexp>,
+C<vendorhtml1dir>, C<vendorhtml1direxp>, C<vendorhtml3dir>,
+C<vendorhtml3direxp>, C<vendorlib>, C<vendorlib_stem>, C<vendorlibexp>,
+C<vendorman1dir>, C<vendorman1direxp>, C<vendorman3dir>,
+C<vendorman3direxp>, C<vendorprefix>, C<vendorprefixexp>, C<vendorscript>,
+C<vendorscriptexp>, C<version>, C<version_patchlevel_string>,
+C<versiononly>, C<vi>, C<voidflags>
+
+=over 4
+
+=item x
+
+=back
+
+C<xlibpth>
+
+=over 4
+
+=item y
+
+=back
+
+C<yacc>, C<yaccflags>
+
+=over 4
+
+=item z
+
+=back
+
+C<zcat>, C<zip>
+
+=over 4
+
+=item GIT DATA
+
+=item NOTE
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+dynamic, nonxs, static
+
+=item AUTHOR
+
+=back
+
+=head2 Cwd - get pathname of current working directory
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item getcwd and friends
+
+getcwd, cwd, fastcwd, fastgetcwd, getdcwd
+
+=item abs_path and friends
+
+abs_path, realpath, fast_abs_path
+
+=item $ENV{PWD}
+
+=back
+
+=item NOTES
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 DB - programmatic interface to the Perl debugging API
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Global Variables
+
+ $DB::sub, %DB::sub, $DB::single, $DB::signal, $DB::trace, @DB::args,
+@DB::dbline, %DB::dbline, $DB::package, $DB::filename, $DB::subname,
+$DB::lineno
+
+=item API Methods
+
+CLIENT->register(), CLIENT->evalcode(STRING), CLIENT->skippkg('D::hide'),
+CLIENT->run(), CLIENT->step(), CLIENT->next(), CLIENT->done()
+
+=item Client Callback Methods
+
+CLIENT->init(), CLIENT->prestop([STRING]), CLIENT->stop(), CLIENT->idle(),
+CLIENT->poststop([STRING]), CLIENT->evalcode(STRING), CLIENT->cleanup(),
+CLIENT->output(LIST)
+
+=back
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter -- Filter DBM keys/values
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item What is a DBM Filter?
+
+=over 4
+
+=item So what's new?
+
+=back
+
+=item METHODS
+
+=over 4
+
+=item $db->Filter_Push()
+
+=item $db->Filter_Key_Push()
+
+=item $db->Filter_Value_Push()
+
+Filter_Push, Filter_Key_Push, Filter_Value_Push
+
+=item $db->Filter_Pop()
+
+=item $db->Filtered()
+
+=back
+
+=item Writing a Filter
+
+=over 4
+
+=item Immediate Filters
+
+=item Canned Filters
+
+"name", params
+
+=back
+
+=item Filters Included
+
+utf8, encode, compress, int32, null
+
+=item NOTES
+
+=over 4
+
+=item Maintain Round Trip Integrity
+
+=item Don't mix filtered & non-filtered data in the same database file.
+
+=back
+
+=item EXAMPLE
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter::compress - filter for DBM_Filter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter::encode - filter for DBM_Filter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter::int32 - filter for DBM_Filter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter::null - filter for DBM_Filter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 DBM_Filter::utf8 - filter for DBM_Filter
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Data::Dumper - stringified perl data structures, suitable for both
+printing and C<eval>
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Methods
+
+I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>), I<$OBJ>->Dump I<or>
+I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>), I<$OBJ>->Seen(I<[HASHREF]>),
+I<$OBJ>->Values(I<[ARRAYREF]>), I<$OBJ>->Names(I<[ARRAYREF]>),
+I<$OBJ>->Reset
+
+=item Functions
+
+Dumper(I<LIST>)
+
+=item Configuration Variables or Methods
+
+=item Exports
+
+Dumper
+
+=back
+
+=item EXAMPLES
+
+=item BUGS
+
+=over 4
+
+=item NOTE
+
+=back
+
+=item AUTHOR
+
+=item VERSION
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel-DProf, Devel::DProf - a Perl code profiler
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item PROFILE FORMAT
+
+=item AUTOLOAD
+
+=item ENVIRONMENT
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel-Peek, Devel::Peek - A data debugging tool for the XS
+programmer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Runtime debugging
+
+=item Memory footprint debugging
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item A simple scalar string
+
+=item A simple scalar number
+
+=item A simple scalar with an extra reference
+
+=item A reference to a simple scalar
+
+=item A reference to an array
+
+=item A reference to a hash
+
+=item Dumping a large array or hash
+
+=item A reference to an SV which holds a C pointer
+
+=item A reference to a subroutine
+
+=back
+
+=item EXPORTS
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel-SelfStubber::lib::Devel::SelfStubber, Devel::SelfStubber -
+generate stubs for a SelfLoading module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 Devel::DProf - a Perl code profiler
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item PROFILE FORMAT
+
+=item AUTOLOAD
+
+=item ENVIRONMENT
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel::InnerPackage - find all the inner packages of a package
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item list_packages <package name>
+
+=back
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item COPYING
+
+=item BUGS
+
+=back
+
+=head2 Devel::PPPort - Perl/Pollution/Portability
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Why use ppport.h?
+
+=item How to use ppport.h
+
+=item Running ppport.h
+
+=back
+
+=item FUNCTIONS
+
+=over 4
+
+=item WriteFile
+
+=back
+
+=item COMPATIBILITY
+
+=over 4
+
+=item Provided Perl compatibility API
+
+=item Perl API not supported by ppport.h
+
+perl 5.11.0, perl 5.10.0, perl 5.9.5, perl 5.9.4, perl 5.9.3, perl 5.9.2,
+perl 5.9.1, perl 5.9.0, perl 5.8.3, perl 5.8.1, perl 5.8.0, perl 5.7.3,
+perl 5.7.2, perl 5.7.1, perl 5.6.1, perl 5.6.0, perl 5.005_03, perl 5.005,
+perl 5.004_05, perl 5.004
+
+=back
+
+=item BUGS
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel::Peek - A data debugging tool for the XS programmer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Runtime debugging
+
+=item Memory footprint debugging
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item A simple scalar string
+
+=item A simple scalar number
+
+=item A simple scalar with an extra reference
+
+=item A reference to a simple scalar
+
+=item A reference to an array
+
+=item A reference to a hash
+
+=item Dumping a large array or hash
+
+=item A reference to an SV which holds a C pointer
+
+=item A reference to a subroutine
+
+=back
+
+=item EXPORTS
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Devel::SelfStubber - generate stubs for a SelfLoading module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 Digest - Modules that calculate message digests
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+I<binary>, I<hex>, I<base64>
+
+=item OO INTERFACE
+
+$ctx = Digest->XXX($arg,...), $ctx = Digest->new(XXX => $arg,...), $ctx =
+Digest::XXX->new($arg,...), $other_ctx = $ctx->clone, $ctx->reset,
+$ctx->add( $data ), $ctx->add( $chunk1, $chunk2, ... ), $ctx->addfile(
+$io_handle ), $ctx->add_bits( $data, $nbits ), $ctx->add_bits( $bitstring
+), $ctx->digest, $ctx->hexdigest, $ctx->b64digest
+
+=item Digest speed
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Digest::MD5 - Perl interface to the MD5 Algorithm
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+md5($data,...), md5_hex($data,...), md5_base64($data,...)
+
+=item METHODS
+
+$md5 = Digest::MD5->new, $md5->reset, $md5->clone, $md5->add($data,...),
+$md5->addfile($io_handle), $md5->add_bits($data, $nbits),
+$md5->add_bits($bitstring), $md5->digest, $md5->hexdigest, $md5->b64digest
+
+=item EXAMPLES
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=item AUTHORS
+
+=back
+
+=head2 Digest::SHA - Perl extension for SHA-1/224/256/384/512
+
+=over 4
+
+=item SYNOPSIS
+
+=item SYNOPSIS (HMAC-SHA)
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item NIST STATEMENT ON SHA-1
+
+=item PADDING OF BASE64 DIGESTS
+
+=item EXPORT
+
+=item EXPORTABLE FUNCTIONS
+
+B<sha1($data, ...)>, B<sha224($data, ...)>, B<sha256($data, ...)>,
+B<sha384($data, ...)>, B<sha512($data, ...)>, B<sha1_hex($data, ...)>,
+B<sha224_hex($data, ...)>, B<sha256_hex($data, ...)>, B<sha384_hex($data,
+...)>, B<sha512_hex($data, ...)>, B<sha1_base64($data, ...)>,
+B<sha224_base64($data, ...)>, B<sha256_base64($data, ...)>,
+B<sha384_base64($data, ...)>, B<sha512_base64($data, ...)>, B<new($alg)>,
+B<reset($alg)>, B<hashsize>, B<algorithm>, B<clone>, B<add($data, ...)>,
+B<add_bits($data, $nbits)>, B<add_bits($bits)>, B<addfile(*FILE)>,
+B<addfile($filename [, $mode])>, B<dump($filename)>, B<load($filename)>,
+B<digest>, B<hexdigest>, B<b64digest>, B<hmac_sha1($data, $key)>,
+B<hmac_sha224($data, $key)>, B<hmac_sha256($data, $key)>,
+B<hmac_sha384($data, $key)>, B<hmac_sha512($data, $key)>,
+B<hmac_sha1_hex($data, $key)>, B<hmac_sha224_hex($data, $key)>,
+B<hmac_sha256_hex($data, $key)>, B<hmac_sha384_hex($data, $key)>,
+B<hmac_sha512_hex($data, $key)>, B<hmac_sha1_base64($data, $key)>,
+B<hmac_sha224_base64($data, $key)>, B<hmac_sha256_base64($data, $key)>,
+B<hmac_sha384_base64($data, $key)>, B<hmac_sha512_base64($data, $key)>
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item ACKNOWLEDGMENTS
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Digest::base - Digest base class
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 Digest::file - Calculate digests of files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+digest_file( $file, $algorithm, [$arg,...] ), digest_file_hex( $file,
+$algorithm, [$arg,...] ), digest_file_base64( $file, $algorithm, [$arg,...]
+)
+
+=item SEE ALSO
+
+=back
+
+=head2 DirHandle - supply object methods for directory handles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=back
+
+=head2 Dumpvalue - provides screen dump of Perl data.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Creation
+
+C<arrayDepth>, C<hashDepth>, C<compactDump>, C<veryCompact>, C<globPrint>,
+C<dumpDBFiles>, C<dumpPackages>, C<dumpReused>, C<tick>, C<quoteHighBit>,
+C<printUndef>, C<usageOnly>, unctrl, subdump, bareStringify, quoteHighBit,
+stopDbSignal
+
+=item Methods
+
+dumpValue, dumpValues, stringify, dumpvars, set_quote, set_unctrl,
+compactDump, veryCompact, set, get
+
+=back
+
+=back
+
+=head2 DynaLoader - Dynamically load C libraries into Perl code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+@dl_library_path, @dl_resolve_using, @dl_require_symbols, @dl_librefs,
+@dl_modules, @dl_shared_objects, dl_error(), $dl_debug, dl_findfile(),
+dl_expandspec(), dl_load_file(), dl_unload_file(), dl_load_flags(),
+dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(),
+dl_install_xsub(), bootstrap()
+
+=item AUTHOR
+
+=back
+
+=head2 Encode - character encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=over 4
+
+=item Table of Contents
+
+=back
+
+=item DESCRIPTION
+
+=over 4
+
+=item TERMINOLOGY
+
+=back
+
+=item PERL ENCODING API
+
+$octets = encode(ENCODING, $string [, CHECK]), $string = decode(ENCODING,
+$octets [, CHECK]), [$obj =] find_encoding(ENCODING), [$length =]
+from_to($octets, FROM_ENC, TO_ENC [, CHECK]), $octets =
+encode_utf8($string);, $string = decode_utf8($octets [, CHECK]);
+
+=over 4
+
+=item Listing available encodings
+
+=item Defining Aliases
+
+=item Finding IANA Character Set Registry names
+
+=back
+
+=item Encoding via PerlIO
+
+=item Handling Malformed Data
+
+B<NOTE:> Not all encoding support this feature, I<CHECK> =
+Encode::FB_DEFAULT ( == 0), I<CHECK> = Encode::FB_CROAK ( == 1), I<CHECK> =
+Encode::FB_QUIET, I<CHECK> = Encode::FB_WARN, perlqq mode (I<CHECK> =
+Encode::FB_PERLQQ), HTML charref mode (I<CHECK> = Encode::FB_HTMLCREF), XML
+charref mode (I<CHECK> = Encode::FB_XMLCREF), The bitmask,
+Encode::LEAVE_SRC
+
+=over 4
+
+=item coderef for CHECK
+
+=back
+
+=item Defining Encodings
+
+=item The UTF8 flag
+
+Goal #1:, Goal #2:, Goal #3:, Goal #4:
+
+=over 4
+
+=item Messing with Perl's Internals
+
+is_utf8(STRING [, CHECK]), _utf8_on(STRING), _utf8_off(STRING)
+
+=back
+
+=item UTF-8 vs. utf8 vs. UTF8
+
+=item SEE ALSO
+
+=item MAINTAINER
+
+=item COPYRIGHT
+
+=back
+
+=head2 Encode::Alias - alias definitions to encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+As a simple string, As a qr// compiled regular expression, e.g.:, As a code
+reference, e.g.:
+
+=over 4
+
+=item Alias overloading
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Byte - Single Byte Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::CJKConstants -- Internally used by Encode::??::ISO_2022_*
+
+=head2 Encode::CN - China-based Chinese Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::CN::HZ -- internally used by Encode::CN
+
+=head2 Encode::Config -- internally used by Encode
+
+=head2 Encode::EBCDIC - EBCDIC Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Encoding - Encode Implementation Base Class
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Methods you should implement
+
+-E<gt>encode($string [,$check]), -E<gt>decode($octets [,$check]),
+-E<gt>cat_decode($destination, $octets, $offset, $terminator [,$check])
+
+=item Other methods defined in Encode::Encodings
+
+-E<gt>name, -E<gt>mime_name, -E<gt>renew, -E<gt>renewed, -E<gt>perlio_ok(),
+-E<gt>needs_lines()
+
+=item Example: Encode::ROT13
+
+=back
+
+=item Why the heck Encode API is different?
+
+=over 4
+
+=item Compiled Encodings
+
+=back
+
+=item SEE ALSO
+
+Scheme 1, Scheme 2, Other Schemes
+
+=back
+
+=head2 Encode::GSM0338 -- ESTI GSM 03.38 Encoding
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Guess -- Guesses encoding from data
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+Encode::Guess->set_suspects, Encode::Guess->add_suspects,
+Encode::decode("Guess" ...), Encode::Guess->guess($data),
+guess_encoding($data, [, I<list of suspects>])
+
+=item CAVEATS
+
+=item TO DO
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::JP - Japanese Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item Note on ISO-2022-JP(-1)?
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::JP::H2Z -- internally used by Encode::JP::2022_JP*
+
+=head2 Encode::JP::JIS7 -- internally used by Encode::JP
+
+=head2 Encode::KR - Korean Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::KR::2022_KR -- internally used by Encode::KR
+
+=head2 Encode::MIME::Header -- MIME 'B' and 'Q' header encoding
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::MIME::Name, Encode::MIME::NAME -- internally used by Encode
+
+=over 4
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::PerlIO -- a detailed document on Encode and PerlIO
+
+=over 4
+
+=item Overview
+
+=item How does it work?
+
+=item Line Buffering
+
+=over 4
+
+=item How can I tell whether my encoding fully supports PerlIO ?
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Supported -- Encodings supported by Encode
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Encoding Names
+
+=back
+
+=item Supported Encodings
+
+=over 4
+
+=item Built-in Encodings
+
+=item Encode::Unicode -- other Unicode encodings
+
+=item Encode::Byte -- Extended ASCII
+
+ISO-8859 and corresponding vendor mappings, KOI8 - De Facto Standard for
+the Cyrillic world
+
+=item gsm0338 - Hentai Latin 1
+
+gsm0338 support before 2.19
+
+=item CJK: Chinese, Japanese, Korean (Multibyte)
+
+Encode::CN -- Continental China, Encode::JP -- Japan, Encode::KR -- Korea,
+Encode::TW -- Taiwan, Encode::HanExtra -- More Chinese via CPAN,
+Encode::JIS2K -- JIS X 0213 encodings via CPAN
+
+=item Miscellaneous encodings
+
+Encode::EBCDIC, Encode::Symbols, Encode::MIME::Header, Encode::Guess
+
+=back
+
+=item Unsupported encodings
+
+ ISO-2022-JP-2 [RFC1554], ISO-2022-CN [RFC1922], Various HP-UX encodings,
+Cyrillic encoding ISO-IR-111, ISO-8859-8-1 [Hebrew], ISIRI 3342, Iran
+System, ISIRI 2900 [Farsi], Thai encoding TCVN, Vietnamese encodings VPS,
+Various Mac encodings, (Mac) Indic encodings
+
+=item Encoding vs. Charset -- terminology
+
+=item Encoding Classification (by Anton Tagunov and Dan Kogai)
+
+=over 4
+
+=item Microsoft-related naming mess
+
+KS_C_5601-1987, GB2312, Big5, Shift_JIS
+
+=back
+
+=item Glossary
+
+character repertoire, coded character set (CCS), character encoding scheme
+(CES), charset (in MIME context), EUC, ISO-2022, UCS, UCS-2, Unicode, UTF,
+UTF-16
+
+=item See Also
+
+=item References
+
+ECMA, ECMA-035 (eq C<ISO-2022>), IANA, Assigned Charset Names by IANA, ISO,
+RFC, UC, Unicode Glossary
+
+=over 4
+
+=item Other Notable Sites
+
+czyborra.com, CJK.inf, Jungshik Shin's Hangul FAQ, debian.org:
+"Introduction to i18n"
+
+=item Offline sources
+
+C<CJKV Information Processing> by Ken Lunde
+
+=back
+
+=back
+
+=head2 Encode::Symbol - Symbol Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::TW - Taiwan-based Chinese Encodings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Unicode -- Various Unicode Transformation Formats
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+L<http://www.unicode.org/glossary/> says:, Quick Reference
+
+=item Size, Endianness, and BOM
+
+=over 4
+
+=item by size
+
+=item by endianness
+
+BOM as integer when fetched in network byte order
+
+=back
+
+=item Surrogate Pairs
+
+=item Error Checking
+
+=item SEE ALSO
+
+=back
+
+=head2 Encode::Unicode::UTF7 -- UTF-7 encoding
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item In Practice
+
+=item SEE ALSO
+
+=back
+
+=head2 Encoder, Encode::Encoder -- Object Oriented Encoder
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item Description
+
+=over 4
+
+=item Predefined Methods
+
+$e = Encode::Encoder-E<gt>new([$data, $encoding]);, encoder(),
+$e-E<gt>data([$data]), $e-E<gt>encoding([$encoding]),
+$e-E<gt>bytes([$encoding])
+
+=item Example: base64 transcoder
+
+=item Operator Overloading
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 English - use nice English (or awk) names for ugly punctuation
+variables
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item PERFORMANCE
+
+=back
+
+=head2 Env - perl module that imports environment variables as scalars or
+arrays
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item LIMITATIONS
+
+=item AUTHOR
+
+=back
+
+=head2 Errno - System errno constants
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEATS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Exporter - Implements default import method for modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item How to Export
+
+=item Selecting What To Export
+
+=item How to Import
+
+C<use YourModule;>, C<use YourModule ();>, C<use YourModule qw(...);>
+
+=back
+
+=item Advanced features
+
+=over 4
+
+=item Specialised Import Lists
+
+=item Exporting without using Exporter's import method
+
+=item Exporting without inheriting from Exporter
+
+=item Module Version Checking
+
+=item Managing Unknown Symbols
+
+=item Tag Handling Utility Functions
+
+=item Generating combined tags
+
+=item C<AUTOLOAD>ed Constants
+
+=back
+
+=item Good Practices
+
+=over 4
+
+=item Declaring C<@EXPORT_OK> and Friends
+
+=item Playing Safe
+
+=item What not to Export
+
+=back
+
+=item SEE ALSO
+
+=item LICENSE
+
+=back
+
+=head2 Exporter::Heavy - Exporter guts
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::CBuilder - Compile and link C code for Perl modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+new, have_compiler, have_cplusplus, compile, C<object_file>,
+C<include_dirs>, C<extra_compiler_flags>, C<C++>, link, lib_file,
+module_name, extra_linker_flags, link_executable, exe_file, object_file,
+lib_file, exe_file, prelink, need_prelink, extra_link_args_after_prelink
+
+=item TO DO
+
+=item HISTORY
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::CBuilder::Platform::Windows - Builder class for Windows
+platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::Command - utilities to replace common UNIX commands in
+Makefiles etc.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item FUNCTIONS
+
+=back
+
+=back
+
+cat
+
+eqtime
+
+rm_rf
+
+rm_f
+
+touch
+
+mv
+
+cp
+
+chmod
+
+mkpath
+
+test_f
+
+test_d
+
+dos2unix
+
+=over 4
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Command::MM - Commands for the MM's to use in Makefiles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<test_harness>
+
+=back
+
+B<pod2man>
+
+B<warn_if_old_packlist>
+
+B<perllocal_install>
+
+B<uninstall>
+
+=head2 ExtUtils::Constant - generate XS code to import C header constants
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+IV, UV, NV, PV, PVN, SV, YES, NO, UNDEF
+
+=item FUNCTIONS
+
+=back
+
+constant_types
+
+XS_constant PACKAGE, TYPES, XS_SUBNAME, C_SUBNAME
+
+autoload PACKAGE, VERSION, AUTOLOADER
+
+WriteMakefileSnippet
+
+WriteConstants ATTRIBUTE =E<gt> VALUE [, ...], NAME, DEFAULT_TYPE,
+BREAKOUT_AT, NAMES, PROXYSUBS, C_FH, C_FILE, XS_FH, XS_FILE, XS_SUBNAME,
+C_SUBNAME
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Constant::Base - base class for ExtUtils::Constant objects
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+=back
+
+header
+
+memEQ_clause args_hashref
+
+dump_names arg_hashref, ITEM..
+
+assign arg_hashref, VALUE..
+
+return_clause arg_hashref, ITEM
+
+switch_clause arg_hashref, NAMELEN, ITEMHASH, ITEM..
+
+params WHAT
+
+dogfood arg_hashref, ITEM..
+
+normalise_items args, default_type, seen_types, seen_items, ITEM..
+
+C_constant arg_hashref, ITEM.., name, type, value, macro, default, pre,
+post, def_pre, def_post, utf8, weight
+
+=over 4
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Constant::Utils - helper functions for ExtUtils::Constant
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+C_stringify NAME
+
+=back
+
+perl_stringify NAME
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Constant::XS - generate C code for XS modules' constants.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Embed - Utilities for embedding Perl in C/C++ applications
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item @EXPORT
+
+=item FUNCTIONS
+
+xsinit(), Examples, ldopts(), Examples, perl_inc(), ccflags(), ccdlflags(),
+ccopts(), xsi_header(), xsi_protos(@modules), xsi_body(@modules)
+
+=item EXAMPLES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Install - install files from here to there
+
+=over 4
+
+=item SYNOPSIS
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+_chmod($$;$), _warnonce(@), _choke(@)
+
+=back
+
+_move_file_at_boot( $file, $target, $moan )
+
+_unlink_or_rename( $file, $tryhard, $installing )
+
+=over 4
+
+=item Functions
+
+_get_install_skip
+
+=back
+
+_have_write_access
+
+_can_write_dir(C<$dir>)
+
+_mkpath($dir,$show,$mode,$verbose,$dry_run)
+
+_copy($from,$to,$verbose,$dry_run)
+
+_chdir($from)
+
+B<install>
+
+_do_cleanup
+
+install_rooted_file( $file ), install_rooted_dir( $dir )
+
+forceunlink( $file, $tryhard )
+
+directory_not_empty( $dir )
+
+B<install_default> I<DISCOURAGED>
+
+B<uninstall>
+
+inc_uninstall($filepath,$libdir,$verbose,$dry_run,$ignore,$results)
+
+run_filter($cmd,$src,$dest)
+
+B<pm_to_blib>
+
+_autosplit
+
+_invokant
+
+=over 4
+
+=item ENVIRONMENT
+
+B<PERL_INSTALL_ROOT>, B<EU_INSTALL_IGNORE_SKIP>,
+B<EU_INSTALL_SITE_SKIPFILE>, B<EU_INSTALL_ALWAYS_COPY>
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 ExtUtils::Installed - Inventory management of installed modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+=item METHODS
+
+new(), modules(), files(), directories(), directory_tree(), validate(),
+packlist(), version()
+
+=item EXAMPLE
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Liblist - determine libraries to use and how to use them
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+For static extensions, For dynamic extensions at build/link time, For
+dynamic extensions at load time
+
+=over 4
+
+=item EXTRALIBS
+
+=item LDLOADLIBS and LD_RUN_PATH
+
+=item BSLOADLIBS
+
+=back
+
+=item PORTABILITY
+
+=over 4
+
+=item VMS implementation
+
+=item Win32 implementation
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM - OS adjusted ExtUtils::MakeMaker subclass
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::MM_AIX - AIX specific subclass of ExtUtils::MM_Unix
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+=back
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_Any - Platform-agnostic MM methods
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Cross-platform helper methods
+
+=back
+
+=back
+
+=over 4
+
+=item Targets
+
+=back
+
+=over 4
+
+=item Init methods
+
+=back
+
+=over 4
+
+=item Tools
+
+=back
+
+=over 4
+
+=item File::Spec wrappers
+
+=back
+
+=over 4
+
+=item Misc
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::MM_BeOS - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+os_flavor
+
+init_linker
+
+=head2 ExtUtils::MM_Cygwin - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+os_flavor
+
+=back
+
+cflags
+
+replace_manpage_separator
+
+init_linker
+
+maybe_command
+
+=head2 ExtUtils::MM_DOS - DOS specific subclass of ExtUtils::MM_Unix
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+os_flavor
+
+=back
+
+=back
+
+B<replace_manpage_separator>
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_Darwin - special behaviors for OS X
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overriden Methods
+
+=back
+
+=back
+
+=head2 ExtUtils::MM_MacOS - once produced Makefiles for MacOS Classic
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::MM_NW5 - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+os_flavor
+
+init_platform, platform_constants
+
+const_cccmd
+
+static_lib
+
+dynamic_lib
+
+=head2 ExtUtils::MM_OS2 - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+init_dist
+
+=back
+
+init_linker
+
+os_flavor
+
+=head2 ExtUtils::MM_QNX - QNX specific subclass of ExtUtils::MM_Unix
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+=back
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_UWIN - U/WIN specific subclass of ExtUtils::MM_Unix
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+os_flavor
+
+=back
+
+=back
+
+B<replace_manpage_separator>
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_Unix - methods used by ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=back
+
+=over 4
+
+=item Methods
+
+os_flavor
+
+=back
+
+c_o (o)
+
+cflags (o)
+
+const_cccmd (o)
+
+const_config (o)
+
+const_loadlibs (o)
+
+constants (o)
+
+depend (o)
+
+init_DEST
+
+init_dist
+
+dist (o)
+
+dist_basics (o)
+
+dist_ci (o)
+
+dist_core (o)
+
+B<dist_target>
+
+B<tardist_target>
+
+B<zipdist_target>
+
+B<tarfile_target>
+
+zipfile_target
+
+uutardist_target
+
+shdist_target
+
+dlsyms (o)
+
+dynamic_bs (o)
+
+dynamic_lib (o)
+
+exescan
+
+extliblist
+
+find_perl
+
+fixin
+
+force (o)
+
+guess_name
+
+has_link_code
+
+init_dirscan
+
+init_MANPODS
+
+init_MAN1PODS
+
+init_MAN3PODS
+
+init_PM
+
+init_DIRFILESEP
+
+init_main
+
+init_others
+
+init_linker
+
+init_lib2arch
+
+init_PERL
+
+init_platform, platform_constants
+
+init_PERM
+
+init_xs
+
+install (o)
+
+installbin (o)
+
+linkext (o)
+
+lsdir
+
+macro (o)
+
+makeaperl (o)
+
+makefile (o)
+
+maybe_command
+
+needs_linking (o)
+
+parse_abstract
+
+parse_version
+
+pasthru (o)
+
+perl_script
+
+perldepend (o)
+
+pm_to_blib
+
+post_constants (o)
+
+post_initialize (o)
+
+postamble (o)
+
+ppd
+
+prefixify
+
+processPL (o)
+
+quote_paren
+
+replace_manpage_separator
+
+cd
+
+oneliner
+
+quote_literal
+
+escape_newlines
+
+max_exec_len
+
+static (o)
+
+static_lib (o)
+
+staticmake (o)
+
+subdir_x (o)
+
+subdirs (o)
+
+test (o)
+
+test_via_harness (override)
+
+test_via_script (override)
+
+tool_xsubpp (o)
+
+all_target
+
+top_targets (o)
+
+writedoc
+
+xs_c (o)
+
+xs_cpp (o)
+
+xs_o (o)
+
+=over 4
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_VMS - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Methods always loaded
+
+wraplist
+
+=back
+
+=back
+
+=over 4
+
+=item Methods
+
+guess_name (override)
+
+=back
+
+find_perl (override)
+
+maybe_command (override)
+
+pasthru (override)
+
+pm_to_blib (override)
+
+perl_script (override)
+
+replace_manpage_separator
+
+init_DEST
+
+init_DIRFILESEP
+
+init_main (override)
+
+init_others (override)
+
+init_platform (override)
+
+platform_constants
+
+init_VERSION (override)
+
+constants (override)
+
+special_targets
+
+cflags (override)
+
+const_cccmd (override)
+
+tools_other (override)
+
+init_dist (override)
+
+c_o (override)
+
+xs_c (override)
+
+xs_o (override)
+
+dlsyms (override)
+
+dynamic_lib (override)
+
+static_lib (override)
+
+extra_clean_files
+
+zipfile_target, tarfile_target, shdist_target
+
+install (override)
+
+perldepend (override)
+
+makeaperl (override)
+
+maketext_filter (override)
+
+prefixify (override)
+
+cd
+
+oneliner
+
+B<echo>
+
+quote_literal
+
+escape_newlines
+
+max_exec_len
+
+init_linker
+
+catdir (override), catfile (override)
+
+eliminate_macros
+
+fixpath
+
+os_flavor
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::MM_VOS - VOS specific subclass of ExtUtils::MM_Unix
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+=back
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MM_Win32 - methods to override UN*X behaviour in
+ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item Overridden methods
+
+B<dlsyms>
+
+=back
+
+replace_manpage_separator
+
+B<maybe_command>
+
+B<init_DIRFILESEP>
+
+B<init_others>
+
+init_platform, platform_constants
+
+special_targets
+
+static_lib
+
+dynamic_lib
+
+extra_clean_files
+
+init_linker
+
+perl_script
+
+xs_o
+
+pasthru
+
+arch_check (override)
+
+oneliner
+
+cd
+
+max_exec_len
+
+os_flavor
+
+cflags
+
+=head2 ExtUtils::MM_Win95 - method to customize MakeMaker for Win9X
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden methods
+
+xs_c
+
+=back
+
+=back
+
+xs_cpp
+
+xs_o
+
+max_exec_len
+
+os_flavor
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::MY - ExtUtils::MakeMaker subclass for customization
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::MakeMaker - Create a module Makefile
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item How To Write A Makefile.PL
+
+=item Default Makefile Behaviour
+
+=item make test
+
+=item make testdb
+
+=item make install
+
+=item INSTALL_BASE
+
+=item PREFIX and LIB attribute
+
+=item AFS users
+
+=item Static Linking of a new Perl Binary
+
+=item Determination of Perl Library and Installation Locations
+
+=item Which architecture dependent directory?
+
+=item Using Attributes and Parameters
+
+ABSTRACT, ABSTRACT_FROM, AUTHOR, BINARY_LOCATION, BUILD_REQUIRES, C,
+CCFLAGS, CONFIG, CONFIGURE, CONFIGURE_REQUIRES, DEFINE, DESTDIR, DIR,
+DISTNAME, DISTVNAME, DL_FUNCS, DL_VARS, EXCLUDE_EXT, EXE_FILES,
+FIRST_MAKEFILE, FULLPERL, FULLPERLRUN, FULLPERLRUNINST, FUNCLIST, H,
+IMPORTS, INC, INCLUDE_EXT, INSTALLARCHLIB, INSTALLBIN, INSTALLDIRS,
+INSTALLMAN1DIR, INSTALLMAN3DIR, INSTALLPRIVLIB, INSTALLSCRIPT,
+INSTALLSITEARCH, INSTALLSITEBIN, INSTALLSITELIB, INSTALLSITEMAN1DIR,
+INSTALLSITEMAN3DIR, INSTALLSITESCRIPT, INSTALLVENDORARCH, INSTALLVENDORBIN,
+INSTALLVENDORLIB, INSTALLVENDORMAN1DIR, INSTALLVENDORMAN3DIR,
+INSTALLVENDORSCRIPT, INST_ARCHLIB, INST_BIN, INST_LIB, INST_MAN1DIR,
+INST_MAN3DIR, INST_SCRIPT, LD, LDDLFLAGS, LDFROM, LIB, LIBPERL_A, LIBS,
+LICENSE, LINKTYPE, MAKE, MAKEAPERL, MAKEFILE_OLD, MAN1PODS, MAN3PODS,
+MAP_TARGET, META_ADD, META_MERGE, MIN_PERL_VERSION, MYEXTLIB, NAME,
+NEEDS_LINKING, NOECHO, NORECURS, NO_META, NO_VC, OBJECT, OPTIMIZE, PERL,
+PERL_CORE, PERLMAINCC, PERL_ARCHLIB, PERL_LIB, PERL_MALLOC_OK, PERLPREFIX,
+PERLRUN, PERLRUNINST, PERL_SRC, PERM_DIR, PERM_RW, PERM_RWX, PL_FILES, PM,
+PMLIBDIRS, PM_FILTER, POLLUTE, PPM_INSTALL_EXEC, PPM_INSTALL_SCRIPT,
+PREFIX, PREREQ_FATAL, PREREQ_PM, PREREQ_PRINT, PRINT_PREREQ, SITEPREFIX,
+SIGN, SKIP, TYPEMAPS, VENDORPREFIX, VERBINST, VERSION, VERSION_FROM,
+VERSION_SYM, XS, XSOPT, XSPROTOARG, XS_VERSION
+
+=item Additional lowercase attributes
+
+clean, depend, dist, dynamic_lib, linkext, macro, postamble, realclean,
+test, tool_autosplit
+
+=item Overriding MakeMaker Methods
+
+=item The End Of Cargo Cult Programming
+
+C<< MAN3PODS => ' ' >>
+
+=item Hintsfile support
+
+=item Distribution Support
+
+ make distcheck, make skipcheck, make distclean, make manifest,
+ make distdir, make disttest, make tardist, make dist, make
+uutardist, make shdist, make zipdist, make ci
+
+=item Module Meta-Data
+
+=item Disabling an extension
+
+=item Other Handy Functions
+
+prompt
+
+=back
+
+=item ENVIRONMENT
+
+PERL_MM_OPT, PERL_MM_USE_DEFAULT, PERL_CORE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item LICENSE
+
+=back
+
+=head2 ExtUtils::MakeMaker::Config - Wrapper around Config.pm
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::MakeMaker::FAQ - Frequently Asked Questions About
+MakeMaker
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Module Installation
+
+How do I install a module into my home directory?, How do I get MakeMaker
+and Module::Build to install to the same place?, How do I keep from
+installing man pages?, How do I use a module without installing it?, PREFIX
+vs INSTALL_BASE from Module::Build::Cookbook
+
+=item Philosophy and History
+
+Why not just use <insert other build config tool here>?, What is
+Module::Build and how does it relate to MakeMaker?, pure perl. no make, no
+shell commands, easier to customize, cleaner internals, less cruft
+
+=item Module Writing
+
+How do I keep my $VERSION up to date without resetting it manually?, What's
+this F<META.yml> thing and how did it get in my F<MANIFEST>?!, How do I
+delete everything not in my F<MANIFEST>?, Which zip should I use on Windows
+for '[nd]make zipdist'?
+
+=item XS
+
+How to I prevent "object version X.XX does not match bootstrap parameter
+Y.YY" errors?, How do I make two or more XS files coexist in the same
+directory?
+
+=back
+
+=item PATCHING
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::MakeMaker::Tutorial - Writing a module with MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item The Mantra
+
+=item The Layout
+
+Makefile.PL, MANIFEST, lib/, t/, Changes, README, INSTALL, MANIFEST.SKIP,
+bin/
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::Manifest - utilities to write and check a MANIFEST file
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Functions
+
+mkmanifest
+
+=back
+
+=back
+
+manifind
+
+manicheck
+
+filecheck
+
+fullcheck
+
+skipcheck
+
+maniread
+
+maniskip
+
+manicopy
+
+maniadd
+
+=over 4
+
+=item MANIFEST
+
+=item MANIFEST.SKIP
+
+#!include_default, #!include /Path/to/another/manifest.skip
+
+=item EXPORT_OK
+
+=item GLOBAL VARIABLES
+
+=back
+
+=over 4
+
+=item DIAGNOSTICS
+
+C<Not in MANIFEST:> I<file>, C<Skipping> I<file>, C<No such file:> I<file>,
+C<MANIFEST:> I<$!>, C<Added to MANIFEST:> I<file>
+
+=item ENVIRONMENT
+
+B<PERL_MM_MANIFEST_DEBUG>
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::Miniperl, writemain - write the C code for perlmain.c
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::Mkbootstrap - make a bootstrap file for use by DynaLoader
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 ExtUtils::Mksymlists - write linker options files for dynamic
+extension
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+DLBASE, DL_FUNCS, DL_VARS, FILE, FUNCLIST, IMPORTS, NAME
+
+=item AUTHOR
+
+=item REVISION
+
+mkfh()
+
+=back
+
+__find_relocations
+
+=head2 ExtUtils::Packlist - manage .packlist files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+=item FUNCTIONS
+
+new(), read(), write(), validate(), packlist_file()
+
+=item EXAMPLE
+
+=item AUTHOR
+
+=back
+
+=head2 ExtUtils::ParseXS - converts Perl XS code into C code
+
+=over 4
+
+=item SYNOPSIS
+
+=item EXPORT
+
+=item FUNCTIONS
+
+process_xs(), B<C++>, B<hiertype>, B<except>, B<typemap>, B<prototypes>,
+B<versioncheck>, B<linenumbers>, B<optimize>, B<inout>, B<argtypes>, B<s>,
+errors()
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 ExtUtils::XSSymSet - keep sets of symbol names palatable to the VMS
+linker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+new([$maxlen[,$silent]]), addsym($name[,$maxlen[,$silent]]),
+trimsym($name[,$maxlen[,$silent]]), delsym($name), get_orig($trimmed),
+get_trimmed($name), all_orig(), all_trimmed()
+
+=item AUTHOR
+
+=item REVISION
+
+=back
+
+=head2 ExtUtils::testlib - add blib/* directories to @INC
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 Fatal - Replace functions with equivalents which succeed or die
+
+=over 4
+
+=item SYNOPSIS
+
+=item BEST PRACTICE
+
+=item DESCRIPTION
+
+=item DIAGNOSTICS
+
+Bad subroutine name for Fatal: %s, %s is not a Perl subroutine, %s is
+neither a builtin, nor a Perl subroutine, Cannot make the non-overridable
+%s fatal, Internal error: %s
+
+=item BUGS
+
+=item AUTHOR
+
+=item LICENSE
+
+=item SEE ALSO
+
+=back
+
+=head2 Fcntl - load the C Fcntl.h defines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item EXPORTED SYMBOLS
+
+=back
+
+=head2 File-Glob, File::Glob - Perl extension for BSD glob routine
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item META CHARACTERS
+
+=item POSIX FLAGS
+
+C<GLOB_ERR>, C<GLOB_LIMIT>, C<GLOB_MARK>, C<GLOB_NOCASE>, C<GLOB_NOCHECK>,
+C<GLOB_NOSORT>, C<GLOB_BRACE>, C<GLOB_NOMAGIC>, C<GLOB_QUOTE>,
+C<GLOB_TILDE>, C<GLOB_CSH>, C<GLOB_ALPHASORT>
+
+=back
+
+=item DIAGNOSTICS
+
+C<GLOB_NOSPACE>, C<GLOB_ABEND>
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 File::Basename - Parse file paths into directory, filename and
+suffix.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+C<fileparse> X<fileparse>
+
+C<basename> X<basename> X<filename>
+
+C<dirname> X<dirname>
+
+C<fileparse_set_fstype> X<filesystem>
+
+=over 4
+
+=item SEE ALSO
+
+=back
+
+=head2 File::CheckTree - run many filetest checks on a tree
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item HISTORY
+
+=back
+
+=head2 File::Compare - Compare files or filehandles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item RETURN
+
+=item AUTHOR
+
+=back
+
+=head2 File::Copy - Copy files or filehandles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+copy X<copy> X<cp>, move X<move> X<mv> X<rename>, syscopy X<syscopy>,
+rmscopy($from,$to[,$date_flag]) X<rmscopy>
+
+=item RETURN
+
+=item NOTES
+
+=item AUTHOR
+
+=back
+
+=head2 File::DosGlob - DOS like globbing and then some
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=item EXPORTS (by request only)
+
+=item BUGS
+
+=item AUTHOR
+
+=item HISTORY
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Fetch - A generic file fetching mechanism
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ACCESSORS
+
+$ff->uri, $ff->scheme, $ff->host, $ff->vol, $ff->share, $ff->path,
+$ff->file
+
+=back
+
+$ff->output_file
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item $ff = File::Fetch->new( uri => 'http://some.where.com/dir/file.txt'
+);
+
+=back
+
+=back
+
+=over 4
+
+=item $where = $ff->fetch( [to => /my/output/dir/ | \$scalar] )
+
+=back
+
+=over 4
+
+=item $ff->error([BOOL])
+
+=back
+
+=over 4
+
+=item HOW IT WORKS
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $File::Fetch::FROM_EMAIL
+
+=item $File::Fetch::USER_AGENT
+
+=item $File::Fetch::FTP_PASSIVE
+
+=item $File::Fetch::TIMEOUT
+
+=item $File::Fetch::WARN
+
+=item $File::Fetch::DEBUG
+
+=item $File::Fetch::BLACKLIST
+
+=item $File::Fetch::METHOD_FAIL
+
+=back
+
+=item MAPPING
+
+=item FREQUENTLY ASKED QUESTIONS
+
+=over 4
+
+=item So how do I use a proxy with File::Fetch?
+
+=item I used 'lynx' to fetch a file, but its contents is all wrong!
+
+=item Files I'm trying to fetch have reserved characters or non-ASCII
+characters in them. What do I do?
+
+=back
+
+=item TODO
+
+Implement $PREFER_BIN
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 File::Find - Traverse a directory tree.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<find>, B<finddepth>
+
+=over 4
+
+=item %options
+
+C<wanted>, C<bydepth>, C<preprocess>, C<postprocess>, C<follow>,
+C<follow_fast>, C<follow_skip>, C<dangling_symlinks>, C<no_chdir>,
+C<untaint>, C<untaint_pattern>, C<untaint_skip>
+
+=item The wanted function
+
+C<$File::Find::dir> is the current directory name,, C<$_> is the current
+filename within that directory, C<$File::Find::name> is the complete
+pathname to the file
+
+=back
+
+=item WARNINGS
+
+=item CAVEAT
+
+$dont_use_nlink, symlinks
+
+=item NOTES
+
+=item BUGS AND CAVEATS
+
+=item HISTORY
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Glob - Perl extension for BSD glob routine
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item META CHARACTERS
+
+=item POSIX FLAGS
+
+C<GLOB_ERR>, C<GLOB_LIMIT>, C<GLOB_MARK>, C<GLOB_NOCASE>, C<GLOB_NOCHECK>,
+C<GLOB_NOSORT>, C<GLOB_BRACE>, C<GLOB_NOMAGIC>, C<GLOB_QUOTE>,
+C<GLOB_TILDE>, C<GLOB_CSH>, C<GLOB_ALPHASORT>
+
+=back
+
+=item DIAGNOSTICS
+
+C<GLOB_NOSPACE>, C<GLOB_ABEND>
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 File::GlobMapper - Extend File Glob to Allow Input and Output Files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Behind The Scenes
+
+=item Limitations
+
+=item Input File Glob
+
+B<~>, B<~user>, B<.>, B<*>, B<?>, B<\>, B<[]>, B<{,}>, B<()>
+
+=item Output File Glob
+
+"*", #1
+
+=item Returned Data
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item A Rename script
+
+=item A few example globmaps
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 File::Path - Create or remove directory trees
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+make_path( $dir1, $dir2, .... ), make_path( $dir1, $dir2, ...., \%opts ),
+mode => $num, verbose => $bool, error => \$err, owner => $owner, user =>
+$owner, uid => $owner, group => $group, mkpath( $dir ), mkpath( $dir,
+$verbose, $mode ), mkpath( [$dir1, $dir2,...], $verbose, $mode ), mkpath(
+$dir1, $dir2,..., \%opt ), remove_tree( $dir1, $dir2, .... ), remove_tree(
+$dir1, $dir2, ...., \%opts ), verbose => $bool, safe => $bool, keep_root =>
+$bool, result => \$res, error => \$err, rmtree( $dir ), rmtree( $dir,
+$verbose, $safe ), rmtree( [$dir1, $dir2,...], $verbose, $safe ), rmtree(
+$dir1, $dir2,..., \%opt )
+
+=over 4
+
+=item ERROR HANDLING
+
+B<NOTE:>
+
+=item NOTES
+
+=back
+
+=item DIAGNOSTICS
+
+mkdir [path]: [errmsg] (SEVERE), No root path(s) specified, No such file or
+directory, cannot fetch initial working directory: [errmsg], cannot stat
+initial working directory: [errmsg], cannot chdir to [dir]: [errmsg],
+directory [dir] changed before chdir, expected dev=[n] ino=[n], actual
+dev=[n] ino=[n], aborting. (FATAL), cannot make directory [dir]
+read+writeable: [errmsg], cannot read [dir]: [errmsg], cannot reset chmod
+[dir]: [errmsg], cannot remove [dir] when cwd is [dir], cannot chdir to
+[parent-dir] from [child-dir]: [errmsg], aborting. (FATAL), cannot stat
+prior working directory [dir]: [errmsg], aborting. (FATAL), previous
+directory [parent-dir] changed before entering [child-dir], expected
+dev=[n] ino=[n], actual dev=[n] ino=[n], aborting. (FATAL), cannot make
+directory [dir] writeable: [errmsg], cannot remove directory [dir]:
+[errmsg], cannot restore permissions of [dir] to [0nnn]: [errmsg], cannot
+make file [file] writeable: [errmsg], cannot unlink file [file]: [errmsg],
+cannot restore permissions of [file] to [0nnn]: [errmsg], unable to map
+[owner] to a uid, ownership not changed");, unable to map [group] to a gid,
+group ownership not changed
+
+=item SEE ALSO
+
+=item BUGS
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=item LICENSE
+
+=back
+
+=head2 File::Spec - portably perform operations on file names
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+canonpath X<canonpath>, catdir X<catdir>, catfile X<catfile>, curdir
+X<curdir>, devnull X<devnull>, rootdir X<rootdir>, tmpdir X<tmpdir>, updir
+X<updir>, no_upwards, case_tolerant, file_name_is_absolute, path X<path>,
+join X<join, path>, splitpath X<splitpath> X<split, path>, splitdir
+X<splitdir> X<split, dir>, catpath(), abs2rel X<abs2rel> X<absolute, path>
+X<relative, path>, rel2abs() X<rel2abs> X<absolute, path> X<relative, path>
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 File::Spec::Cygwin - methods for Cygwin file specs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+canonpath
+
+file_name_is_absolute
+
+tmpdir (override)
+
+case_tolerant
+
+=over 4
+
+=item COPYRIGHT
+
+=back
+
+=head2 File::Spec::Epoc - methods for Epoc file specs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+canonpath()
+
+=over 4
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Spec::Functions - portably perform operations on file names
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Exports
+
+=back
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Spec::Mac - File::Spec for Mac OS (Classic)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+canonpath
+
+=back
+
+catdir()
+
+catfile
+
+curdir
+
+devnull
+
+rootdir
+
+tmpdir
+
+updir
+
+file_name_is_absolute
+
+path
+
+splitpath
+
+splitdir
+
+catpath
+
+abs2rel
+
+rel2abs
+
+=over 4
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Spec::OS2 - methods for OS/2 file specs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+tmpdir, splitpath
+
+=item COPYRIGHT
+
+=back
+
+=head2 File::Spec::Unix - File::Spec for Unix, base for other File::Spec
+modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+canonpath()
+
+=back
+
+catdir()
+
+catfile
+
+curdir
+
+devnull
+
+rootdir
+
+tmpdir
+
+updir
+
+no_upwards
+
+case_tolerant
+
+file_name_is_absolute
+
+path
+
+join
+
+splitpath
+
+splitdir
+
+catpath()
+
+abs2rel
+
+rel2abs()
+
+=over 4
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Spec::VMS - methods for VMS file specs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+canonpath (override)
+
+catdir (override)
+
+catfile (override)
+
+curdir (override)
+
+devnull (override)
+
+rootdir (override)
+
+tmpdir (override)
+
+updir (override)
+
+case_tolerant (override)
+
+path (override)
+
+file_name_is_absolute (override)
+
+splitpath (override)
+
+splitdir (override)
+
+catpath (override)
+
+abs2rel (override)
+
+rel2abs (override)
+
+=over 4
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Spec::Win32 - methods for Win32 file specs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+devnull
+
+=back
+
+tmpdir
+
+case_tolerant
+
+file_name_is_absolute
+
+catfile
+
+canonpath
+
+splitpath
+
+splitdir
+
+catpath
+
+=over 4
+
+=item Note For File::Spec::Win32 Maintainers
+
+=back
+
+=over 4
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 File::Temp - return name and handle of a temporary file safely
+
+=over 4
+
+=item PORTABILITY
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item OBJECT-ORIENTED INTERFACE
+
+B<new>
+
+=back
+
+B<newdir>
+
+B<filename>
+
+B<dirname>, B<unlink_on_destroy>
+
+B<DESTROY>
+
+=over 4
+
+=item FUNCTIONS
+
+B<tempfile>
+
+=back
+
+B<tempdir>
+
+=over 4
+
+=item MKTEMP FUNCTIONS
+
+B<mkstemp>
+
+=back
+
+B<mkstemps>
+
+B<mkdtemp>
+
+B<mktemp>
+
+=over 4
+
+=item POSIX FUNCTIONS
+
+B<tmpnam>
+
+=back
+
+B<tmpfile>
+
+=over 4
+
+=item ADDITIONAL FUNCTIONS
+
+B<tempnam>
+
+=back
+
+=over 4
+
+=item UTILITY FUNCTIONS
+
+B<unlink0>
+
+=back
+
+B<cmpstat>
+
+B<unlink1>
+
+B<cleanup>
+
+=over 4
+
+=item PACKAGE VARIABLES
+
+B<safe_level>, STANDARD, MEDIUM, HIGH
+
+=back
+
+TopSystemUID
+
+B<$KEEP_ALL>, B<$DEBUG>
+
+=over 4
+
+=item WARNING
+
+=over 4
+
+=item Temporary files and NFS
+
+=item Forking
+
+=item Directory removal
+
+=item BINMODE
+
+=back
+
+=item HISTORY
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 File::stat - by-name interface to Perl's built-in stat() functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item ERRORS
+
+-%s is not implemented on a File::stat object
+
+=item WARNINGS
+
+File::stat ignores use filetest 'access', File::stat ignores VMS ACLs
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 FileCache - keep more files open than the system permits
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+cacheout EXPR, cacheout MODE, EXPR
+
+=item CAVEATS
+
+=item BUGS
+
+=back
+
+=head2 FileCache::lib::FileCache, FileCache - keep more files open than the
+system permits
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+cacheout EXPR, cacheout MODE, EXPR
+
+=item CAVEATS
+
+=item BUGS
+
+=back
+
+=head2 FileHandle - supply object methods for filehandles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$fh->print, $fh->printf, $fh->getline, $fh->getlines
+
+=item SEE ALSO
+
+=back
+
+=head2 Filter::Simple - Simplified source filtering
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item The Problem
+
+=item A Solution
+
+=item Disabling or changing <no> behaviour
+
+=item All-in-one interface
+
+=item Filtering only specific components of source code
+
+C<"code">, C<"code_no_comments">, C<"executable">,
+C<"executable_no_comments">, C<"quotelike">, C<"string">, C<"regex">,
+C<"all">
+
+=item Filtering only the code parts of source code
+
+Most source code ceases to be grammatically correct when it is broken up
+into the pieces between string literals and regexes. So the C<'code'>
+and C<'code_no_comments'> component filter behave slightly differently
+from the other partial filters described in the previous section.
+
+=item Using Filter::Simple with an explicit C<import> subroutine
+
+=item Using Filter::Simple and Exporter together
+
+=item How it works
+
+=back
+
+=item AUTHOR
+
+=item CONTACT
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Filter::Util::Call - Perl Source Filter Utility Module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item B<use Filter::Util::Call>
+
+=item B<import()>
+
+=item B<filter() and anonymous sub>
+
+B<$_>, B<$status>, B<filter_read> and B<filter_read_exact>, B<filter_del>
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item Example 1: A simple filter.
+
+=item Example 2: Using the context
+
+=item Example 3: Using the context within the filter
+
+=item Example 4: Using filter_del
+
+=back
+
+=item Filter::Simple
+
+=item AUTHOR
+
+=item DATE
+
+=back
+
+=head2 FindBin - Locate directory of original perl script
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXPORTABLE VARIABLES
+
+=item KNOWN ISSUES
+
+=item KNOWN BUGS
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 GDBM_File - Perl5 access to the gdbm library.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AVAILABILITY
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Getopt::Long - Extended processing of command line options
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Command Line Options, an Introduction
+
+=item Getting Started with Getopt::Long
+
+=over 4
+
+=item Simple options
+
+=item A little bit less simple options
+
+=item Mixing command line option with other arguments
+
+=item Options with values
+
+=item Options with multiple values
+
+=item Options with hash values
+
+=item User-defined subroutines to handle options
+
+=item Options with multiple names
+
+=item Case and abbreviations
+
+=item Summary of Option Specifications
+
+!, +, s, i, o, f, : I<type> [ I<desttype> ], : I<number> [ I<desttype> ], :
++ [ I<desttype> ]
+
+=back
+
+=item Advanced Possibilities
+
+=over 4
+
+=item Object oriented interface
+
+=item Thread Safety
+
+=item Documentation and help texts
+
+=item Parsing options from an arbitrary array
+
+=item Parsing options from an arbitrary string
+
+=item Storing options values in a hash
+
+=item Bundling
+
+=item The lonesome dash
+
+=item Argument callback
+
+=back
+
+=item Configuring Getopt::Long
+
+default, posix_default, auto_abbrev, getopt_compat, gnu_compat, gnu_getopt,
+require_order, permute, bundling (default: disabled), bundling_override
+(default: disabled), ignore_case (default: enabled), ignore_case_always
+(default: disabled), auto_version (default:disabled), auto_help
+(default:disabled), pass_through (default: disabled), prefix,
+prefix_pattern, long_prefix_pattern, debug (default: disabled)
+
+=item Exportable Methods
+
+VersionMessage, C<-message>, C<-msg>, C<-exitval>, C<-output>, HelpMessage
+
+=item Return values and Errors
+
+=item Legacy
+
+=over 4
+
+=item Default destinations
+
+=item Alternative option starters
+
+=item Configuration variables
+
+=back
+
+=item Tips and Techniques
+
+=over 4
+
+=item Pushing multiple values in a hash option
+
+=back
+
+=item Troubleshooting
+
+=over 4
+
+=item GetOptions does not return a false result when an option is not
+supplied
+
+=item GetOptions does not split the command line correctly
+
+=item Undefined subroutine &main::GetOptions called
+
+=item How do I put a "-?" option into a Getopt::Long?
+
+=back
+
+=item AUTHOR
+
+=item COPYRIGHT AND DISCLAIMER
+
+=back
+
+=head2 Getopt::Std, getopt, getopts - Process single-character switches
+with switch clustering
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item C<--help> and C<--version>
+
+=back
+
+=head2 Hash-Util-FieldHash::lib::Hash::Util::FieldHash,
+Hash::Util::FieldHash - Support for Inside-Out Classes
+
+=over 4
+
+=item SYNOPSIS
+
+=item FUNCTIONS
+
+id, id_2obj, register, idhash, idhashes, fieldhash, fieldhashes
+
+=item DESCRIPTION
+
+=over 4
+
+=item The Inside-out Technique
+
+=item Problems of Inside-out
+
+=item Solutions
+
+=item More Problems
+
+=item The Generic Object
+
+=item How to use Field Hashes
+
+=item Garbage-Collected Hashes
+
+=back
+
+=item EXAMPLES
+
+C<init()>, C<first()>, C<last()>, C<name()>, C<Name_hash>, C<Name_id>,
+C<Name_idhash>, C<Name_id_reg>, C<Name_idhash_reg>, C<Name_fieldhash>
+
+=over 4
+
+=item Example 1
+
+=item Example 2
+
+=back
+
+=item GUTS
+
+=over 4
+
+=item The C<PERL_MAGIC_uvar> interface for hashes
+
+=item Weakrefs call uvar magic
+
+=item How field hashes work
+
+=item Internal function Hash::Util::FieldHash::_fieldhash
+
+=back
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Hash-Utilib::Hash::Util, Hash::Util - A selection of general-utility
+hash subroutines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Restricted hashes
+
+B<lock_keys>, B<unlock_keys>
+
+=back
+
+=back
+
+B<lock_keys_plus>
+
+B<lock_value>, B<unlock_value>
+
+B<lock_hash>, B<unlock_hash>
+
+B<lock_hash_recurse>, B<unlock_hash_recurse>
+
+B<hash_unlocked>
+
+B<legal_keys>, B<hidden_keys>, B<all_keys>, B<hash_seed>
+
+B<hv_store>
+
+=over 4
+
+=item Operating on references to hashes.
+
+lock_ref_keys, unlock_ref_keys, lock_ref_keys_plus, lock_ref_value,
+unlock_ref_value, lock_hashref, unlock_hashref, lock_hashref_recurse,
+unlock_hashref_recurse, hash_ref_unlocked, legal_ref_keys, hidden_ref_keys
+
+=back
+
+=over 4
+
+=item CAVEATS
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Hash::Util - A selection of general-utility hash subroutines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Restricted hashes
+
+B<lock_keys>, B<unlock_keys>
+
+=back
+
+=back
+
+B<lock_keys_plus>
+
+B<lock_value>, B<unlock_value>
+
+B<lock_hash>, B<unlock_hash>
+
+B<lock_hash_recurse>, B<unlock_hash_recurse>
+
+B<hash_unlocked>
+
+B<legal_keys>, B<hidden_keys>, B<all_keys>, B<hash_seed>
+
+B<hv_store>
+
+=over 4
+
+=item Operating on references to hashes.
+
+lock_ref_keys, unlock_ref_keys, lock_ref_keys_plus, lock_ref_value,
+unlock_ref_value, lock_hashref, unlock_hashref, lock_hashref_recurse,
+unlock_hashref_recurse, hash_ref_unlocked, legal_ref_keys, hidden_ref_keys
+
+=back
+
+=over 4
+
+=item CAVEATS
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Hash::Util::FieldHash - Support for Inside-Out Classes
+
+=over 4
+
+=item SYNOPSIS
+
+=item FUNCTIONS
+
+id, id_2obj, register, idhash, idhashes, fieldhash, fieldhashes
+
+=item DESCRIPTION
+
+=over 4
+
+=item The Inside-out Technique
+
+=item Problems of Inside-out
+
+=item Solutions
+
+=item More Problems
+
+=item The Generic Object
+
+=item How to use Field Hashes
+
+=item Garbage-Collected Hashes
+
+=back
+
+=item EXAMPLES
+
+C<init()>, C<first()>, C<last()>, C<name()>, C<Name_hash>, C<Name_id>,
+C<Name_idhash>, C<Name_id_reg>, C<Name_idhash_reg>, C<Name_fieldhash>
+
+=over 4
+
+=item Example 1
+
+=item Example 2
+
+=back
+
+=item GUTS
+
+=over 4
+
+=item The C<PERL_MAGIC_uvar> interface for hashes
+
+=item Weakrefs call uvar magic
+
+=item How field hashes work
+
+=item Internal function Hash::Util::FieldHash::_fieldhash
+
+=back
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 I18N-Langinfo, I18N::Langinfo - query locale information
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item EXPORT
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 I18N::Collate - compare 8-bit scalar data according to the current
+locale
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 I18N::LangTags - functions for dealing with RFC3066-style language
+tags
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+the function is_language_tag($lang1)
+
+the function extract_language_tags($whatever)
+
+the function same_language_tag($lang1, $lang2)
+
+the function similarity_language_tag($lang1, $lang2)
+
+the function is_dialect_of($lang1, $lang2)
+
+the function super_languages($lang1)
+
+the function locale2language_tag($locale_identifier)
+
+the function encode_language_tag($lang1)
+
+the function alternate_language_tags($lang1)
+
+the function @langs = panic_languages(@accept_languages)
+
+the function implicate_supers( ...languages... ), the function
+implicate_supers_strictly( ...languages... )
+
+=over 4
+
+=item ABOUT LOWERCASING
+
+=item ABOUT UNICODE PLAINTEXT LANGUAGE TAGS
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=item AUTHOR
+
+=back
+
+=head2 I18N::LangTags::Detect - detect the user's language preferences
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=item ENVIRONMENT
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=item AUTHOR
+
+=back
+
+=head2 I18N::LangTags::List -- tags and names for human languages
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item ABOUT LANGUAGE TAGS
+
+=item LIST OF LANGUAGES
+
+{ab} : Abkhazian, {ace} : Achinese, {ach} : Acoli, {ada} : Adangme, {ady} :
+Adyghe, {aa} : Afar, {afh} : Afrihili, {af} : Afrikaans, [{afa} :
+Afro-Asiatic (Other)], {ak} : Akan, {akk} : Akkadian, {sq} : Albanian,
+{ale} : Aleut, [{alg} : Algonquian languages], [{tut} : Altaic (Other)],
+{am} : Amharic, {i-ami} : Ami, [{apa} : Apache languages], {ar} : Arabic,
+{arc} : Aramaic, {arp} : Arapaho, {arn} : Araucanian, {arw} : Arawak, {hy}
+: Armenian, {an} : Aragonese, [{art} : Artificial (Other)], {ast} :
+Asturian, {as} : Assamese, [{ath} : Athapascan languages], [{aus} :
+Australian languages], [{map} : Austronesian (Other)], {av} : Avaric, {ae}
+: Avestan, {awa} : Awadhi, {ay} : Aymara, {az} : Azerbaijani, {ban} :
+Balinese, [{bat} : Baltic (Other)], {bal} : Baluchi, {bm} : Bambara, [{bai}
+: Bamileke languages], {bad} : Banda, [{bnt} : Bantu (Other)], {bas} :
+Basa, {ba} : Bashkir, {eu} : Basque, {btk} : Batak (Indonesia), {bej} :
+Beja, {be} : Belarusian, {bem} : Bemba, {bn} : Bengali, [{ber} : Berber
+(Other)], {bho} : Bhojpuri, {bh} : Bihari, {bik} : Bikol, {bin} : Bini,
+{bi} : Bislama, {bs} : Bosnian, {bra} : Braj, {br} : Breton, {bug} :
+Buginese, {bg} : Bulgarian, {i-bnn} : Bunun, {bua} : Buriat, {my} :
+Burmese, {cad} : Caddo, {car} : Carib, {ca} : Catalan, [{cau} : Caucasian
+(Other)], {ceb} : Cebuano, [{cel} : Celtic (Other)], [{cai} : Central
+American Indian (Other)], {chg} : Chagatai, [{cmc} : Chamic languages],
+{ch} : Chamorro, {ce} : Chechen, {chr} : Cherokee, {chy} : Cheyenne, {chb}
+: Chibcha, {ny} : Chichewa, {zh} : Chinese, {chn} : Chinook Jargon, {chp} :
+Chipewyan, {cho} : Choctaw, {cu} : Church Slavic, {chk} : Chuukese, {cv} :
+Chuvash, {cop} : Coptic, {kw} : Cornish, {co} : Corsican, {cr} : Cree,
+{mus} : Creek, [{cpe} : English-based Creoles and pidgins (Other)], [{cpf}
+: French-based Creoles and pidgins (Other)], [{cpp} : Portuguese-based
+Creoles and pidgins (Other)], [{crp} : Creoles and pidgins (Other)], {hr} :
+Croatian, [{cus} : Cushitic (Other)], {cs} : Czech, {dak} : Dakota, {da} :
+Danish, {dar} : Dargwa, {day} : Dayak, {i-default} : Default (Fallthru)
+Language, {del} : Delaware, {din} : Dinka, {dv} : Divehi, {doi} : Dogri,
+{dgr} : Dogrib, [{dra} : Dravidian (Other)], {dua} : Duala, {nl} : Dutch,
+{dum} : Middle Dutch (ca.1050-1350), {dyu} : Dyula, {dz} : Dzongkha, {efi}
+: Efik, {egy} : Ancient Egyptian, {eka} : Ekajuk, {elx} : Elamite, {en} :
+English, {enm} : Old English (1100-1500), {ang} : Old English
+(ca.450-1100), {i-enochian} : Enochian (Artificial), {myv} : Erzya, {eo} :
+Esperanto, {et} : Estonian, {ee} : Ewe, {ewo} : Ewondo, {fan} : Fang, {fat}
+: Fanti, {fo} : Faroese, {fj} : Fijian, {fi} : Finnish, [{fiu} :
+Finno-Ugrian (Other)], {fon} : Fon, {fr} : French, {frm} : Middle French
+(ca.1400-1600), {fro} : Old French (842-ca.1400), {fy} : Frisian, {fur} :
+Friulian, {ff} : Fulah, {gaa} : Ga, {gd} : Scots Gaelic, {gl} : Gallegan,
+{lg} : Ganda, {gay} : Gayo, {gba} : Gbaya, {gez} : Geez, {ka} : Georgian,
+{de} : German, {gmh} : Middle High German (ca.1050-1500), {goh} : Old High
+German (ca.750-1050), [{gem} : Germanic (Other)], {gil} : Gilbertese, {gon}
+: Gondi, {gor} : Gorontalo, {got} : Gothic, {grb} : Grebo, {grc} : Ancient
+Greek, {el} : Modern Greek, {gn} : Guarani, {gu} : Gujarati, {gwi} :
+Gwich'in, {hai} : Haida, {ht} : Haitian, {ha} : Hausa, {haw} : Hawaiian,
+{he} : Hebrew, {hz} : Herero, {hil} : Hiligaynon, {him} : Himachali, {hi} :
+Hindi, {ho} : Hiri Motu, {hit} : Hittite, {hmn} : Hmong, {hu} : Hungarian,
+{hup} : Hupa, {iba} : Iban, {is} : Icelandic, {io} : Ido, {ig} : Igbo,
+{ijo} : Ijo, {ilo} : Iloko, [{inc} : Indic (Other)], [{ine} : Indo-European
+(Other)], {id} : Indonesian, {inh} : Ingush, {ia} : Interlingua
+(International Auxiliary Language Association), {ie} : Interlingue, {iu} :
+Inuktitut, {ik} : Inupiaq, [{ira} : Iranian (Other)], {ga} : Irish, {mga} :
+Middle Irish (900-1200), {sga} : Old Irish (to 900), [{iro} : Iroquoian
+languages], {it} : Italian, {ja} : Japanese, {jv} : Javanese, {jrb} :
+Judeo-Arabic, {jpr} : Judeo-Persian, {kbd} : Kabardian, {kab} : Kabyle,
+{kac} : Kachin, {kl} : Kalaallisut, {xal} : Kalmyk, {kam} : Kamba, {kn} :
+Kannada, {kr} : Kanuri, {krc} : Karachay-Balkar, {kaa} : Kara-Kalpak, {kar}
+: Karen, {ks} : Kashmiri, {csb} : Kashubian, {kaw} : Kawi, {kk} : Kazakh,
+{kha} : Khasi, {km} : Khmer, [{khi} : Khoisan (Other)], {kho} : Khotanese,
+{ki} : Kikuyu, {kmb} : Kimbundu, {rw} : Kinyarwanda, {ky} : Kirghiz,
+{i-klingon} : Klingon, {kv} : Komi, {kg} : Kongo, {kok} : Konkani, {ko} :
+Korean, {kos} : Kosraean, {kpe} : Kpelle, {kro} : Kru, {kj} : Kuanyama,
+{kum} : Kumyk, {ku} : Kurdish, {kru} : Kurukh, {kut} : Kutenai, {lad} :
+Ladino, {lah} : Lahnda, {lam} : Lamba, {lo} : Lao, {la} : Latin, {lv} :
+Latvian, {lb} : Letzeburgesch, {lez} : Lezghian, {li} : Limburgish, {ln} :
+Lingala, {lt} : Lithuanian, {nds} : Low German, {art-lojban} : Lojban
+(Artificial), {loz} : Lozi, {lu} : Luba-Katanga, {lua} : Luba-Lulua, {lui}
+: Luiseno, {lun} : Lunda, {luo} : Luo (Kenya and Tanzania), {lus} : Lushai,
+{mk} : Macedonian, {mad} : Madurese, {mag} : Magahi, {mai} : Maithili,
+{mak} : Makasar, {mg} : Malagasy, {ms} : Malay, {ml} : Malayalam, {mt} :
+Maltese, {mnc} : Manchu, {mdr} : Mandar, {man} : Mandingo, {mni} :
+Manipuri, [{mno} : Manobo languages], {gv} : Manx, {mi} : Maori, {mr} :
+Marathi, {chm} : Mari, {mh} : Marshall, {mwr} : Marwari, {mas} : Masai,
+[{myn} : Mayan languages], {men} : Mende, {mic} : Micmac, {min} :
+Minangkabau, {i-mingo} : Mingo, [{mis} : Miscellaneous languages], {moh} :
+Mohawk, {mdf} : Moksha, {mo} : Moldavian, [{mkh} : Mon-Khmer (Other)],
+{lol} : Mongo, {mn} : Mongolian, {mos} : Mossi, [{mul} : Multiple
+languages], [{mun} : Munda languages], {nah} : Nahuatl, {nap} : Neapolitan,
+{na} : Nauru, {nv} : Navajo, {nd} : North Ndebele, {nr} : South Ndebele,
+{ng} : Ndonga, {ne} : Nepali, {new} : Newari, {nia} : Nias, [{nic} :
+Niger-Kordofanian (Other)], [{ssa} : Nilo-Saharan (Other)], {niu} : Niuean,
+{nog} : Nogai, {non} : Old Norse, [{nai} : North American Indian], {no} :
+Norwegian, {nb} : Norwegian Bokmal, {nn} : Norwegian Nynorsk, [{nub} :
+Nubian languages], {nym} : Nyamwezi, {nyn} : Nyankole, {nyo} : Nyoro, {nzi}
+: Nzima, {oc} : Occitan (post 1500), {oj} : Ojibwa, {or} : Oriya, {om} :
+Oromo, {osa} : Osage, {os} : Ossetian; Ossetic, [{oto} : Otomian
+languages], {pal} : Pahlavi, {i-pwn} : Paiwan, {pau} : Palauan, {pi} :
+Pali, {pam} : Pampanga, {pag} : Pangasinan, {pa} : Panjabi, {pap} :
+Papiamento, [{paa} : Papuan (Other)], {fa} : Persian, {peo} : Old Persian
+(ca.600-400 B.C.), [{phi} : Philippine (Other)], {phn} : Phoenician, {pon}
+: Pohnpeian, {pl} : Polish, {pt} : Portuguese, [{pra} : Prakrit languages],
+{pro} : Old Provencal (to 1500), {ps} : Pushto, {qu} : Quechua, {rm} :
+Raeto-Romance, {raj} : Rajasthani, {rap} : Rapanui, {rar} : Rarotongan,
+[{qaa - qtz} : Reserved for local use.], [{roa} : Romance (Other)], {ro} :
+Romanian, {rom} : Romany, {rn} : Rundi, {ru} : Russian, [{sal} : Salishan
+languages], {sam} : Samaritan Aramaic, {se} : Northern Sami, {sma} :
+Southern Sami, {smn} : Inari Sami, {smj} : Lule Sami, {sms} : Skolt Sami,
+[{smi} : Sami languages (Other)], {sm} : Samoan, {sad} : Sandawe, {sg} :
+Sango, {sa} : Sanskrit, {sat} : Santali, {sc} : Sardinian, {sas} : Sasak,
+{sco} : Scots, {sel} : Selkup, [{sem} : Semitic (Other)], {sr} : Serbian,
+{srr} : Serer, {shn} : Shan, {sn} : Shona, {sid} : Sidamo, {sgn-...} : Sign
+Languages, {bla} : Siksika, {sd} : Sindhi, {si} : Sinhalese, [{sit} :
+Sino-Tibetan (Other)], [{sio} : Siouan languages], {den} : Slave
+(Athapascan), [{sla} : Slavic (Other)], {sk} : Slovak, {sl} : Slovenian,
+{sog} : Sogdian, {so} : Somali, {son} : Songhai, {snk} : Soninke, {wen} :
+Sorbian languages, {nso} : Northern Sotho, {st} : Southern Sotho, [{sai} :
+South American Indian (Other)], {es} : Spanish, {suk} : Sukuma, {sux} :
+Sumerian, {su} : Sundanese, {sus} : Susu, {sw} : Swahili, {ss} : Swati,
+{sv} : Swedish, {syr} : Syriac, {tl} : Tagalog, {ty} : Tahitian, [{tai} :
+Tai (Other)], {tg} : Tajik, {tmh} : Tamashek, {ta} : Tamil, {i-tao} : Tao,
+{tt} : Tatar, {i-tay} : Tayal, {te} : Telugu, {ter} : Tereno, {tet} :
+Tetum, {th} : Thai, {bo} : Tibetan, {tig} : Tigre, {ti} : Tigrinya, {tem} :
+Timne, {tiv} : Tiv, {tli} : Tlingit, {tpi} : Tok Pisin, {tkl} : Tokelau,
+{tog} : Tonga (Nyasa), {to} : Tonga (Tonga Islands), {tsi} : Tsimshian,
+{ts} : Tsonga, {i-tsu} : Tsou, {tn} : Tswana, {tum} : Tumbuka, [{tup} :
+Tupi languages], {tr} : Turkish, {ota} : Ottoman Turkish (1500-1928), {crh}
+: Crimean Turkish, {tk} : Turkmen, {tvl} : Tuvalu, {tyv} : Tuvinian, {tw} :
+Twi, {udm} : Udmurt, {uga} : Ugaritic, {ug} : Uighur, {uk} : Ukrainian,
+{umb} : Umbundu, {und} : Undetermined, {ur} : Urdu, {uz} : Uzbek, {vai} :
+Vai, {ve} : Venda, {vi} : Vietnamese, {vo} : Volapuk, {vot} : Votic, [{wak}
+: Wakashan languages], {wa} : Walloon, {wal} : Walamo, {war} : Waray, {was}
+: Washo, {cy} : Welsh, {wo} : Wolof, {x-...} : Unregistered (Semi-Private
+Use), {xh} : Xhosa, {sah} : Yakut, {yao} : Yao, {yap} : Yapese, {ii} :
+Sichuan Yi, {yi} : Yiddish, {yo} : Yoruba, [{ypk} : Yupik languages], {znd}
+: Zande, [{zap} : Zapotec], {zen} : Zenaga, {za} : Zhuang, {zu} : Zulu,
+{zun} : Zuni
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMER
+
+=item AUTHOR
+
+=back
+
+=head2 IO - load various IO modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item DEPRECATED
+
+=back
+
+=head2 IO::Compress::Base - Base Class for IO::Compress modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Compress::Bzip2 - Write bzip2 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item bzip2 $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeIn => 0|1 >>, C<< Append => 0|1 >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< Append => 0|1 >>, A Buffer, A Filename, A
+Filehandle, C<< BlockSize100K => number >>, C<< WorkFactor => number >>,
+C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item print
+
+=item printf
+
+=item syswrite
+
+=item write
+
+=item flush
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item newStream([OPTS])
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Apache::GZip Revisited
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Compress::Deflate - Write RFC 1950 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item deflate $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeIn => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< Append => 0|1 >>, A Buffer, A Filename, A
+Filehandle, C<< Merge => 0|1 >>, -Level, -Strategy, C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item print
+
+=item printf
+
+=item syswrite
+
+=item write
+
+=item flush
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item newStream([OPTS])
+
+=item deflateParams
+
+=back
+
+=item Importing
+
+:all, :constants, :flush, :level, :strategy
+
+=item EXAMPLES
+
+=over 4
+
+=item Apache::GZip Revisited
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Compress::Gzip - Write RFC 1952 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item gzip $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeIn => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< Append => 0|1 >>, A Buffer, A Filename, A
+Filehandle, C<< Merge => 0|1 >>, -Level, -Strategy, C<< Minimal => 0|1 >>,
+C<< Comment => $comment >>, C<< Name => $string >>, C<< Time => $number >>,
+C<< TextFlag => 0|1 >>, C<< HeaderCRC => 0|1 >>, C<< OS_Code => $value >>,
+C<< ExtraField => $data >>, C<< ExtraFlags => $value >>, C<< Strict => 0|1
+>>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item print
+
+=item printf
+
+=item syswrite
+
+=item write
+
+=item flush
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item newStream([OPTS])
+
+=item deflateParams
+
+=back
+
+=item Importing
+
+:all, :constants, :flush, :level, :strategy
+
+=item EXAMPLES
+
+=over 4
+
+=item Apache::GZip Revisited
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Compress::RawDeflate - Write RFC 1951 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item rawdeflate $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeIn => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< Append => 0|1 >>, A Buffer, A Filename, A
+Filehandle, C<< Merge => 0|1 >>, -Level, -Strategy, C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item print
+
+=item printf
+
+=item syswrite
+
+=item write
+
+=item flush
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item newStream([OPTS])
+
+=item deflateParams
+
+=back
+
+=item Importing
+
+:all, :constants, :flush, :level, :strategy
+
+=item EXAMPLES
+
+=over 4
+
+=item Apache::GZip Revisited
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Compress::Zip - Write zip files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item zip $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeIn => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< Append => 0|1 >>, A Buffer, A Filename, A
+Filehandle, C<< Name => $string >>, C<< Time => $number >>, C<< ExtAttr =>
+$attr >>, C<< exTime => [$atime, $mtime, $ctime] >>, C<< exUnix2 => [$uid,
+$gid] >>, C<< Comment => $comment >>, C<< ZipComment => $comment >>, C<<
+Method => $method >>, C<< Stream => 0|1 >>, C<< Zip64 => 0|1 >>, C<<
+TextFlag => 0|1 >>, C<< ExtraFieldLocal => $data >> =item C<<
+ExtraFieldCentral => $data >>, C<< Minimal => 1|0 >>, C<< BlockSize100K =>
+number >>, C<< WorkFactor => number >>, -Level, -Strategy, C<< Strict =>
+0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item print
+
+=item printf
+
+=item syswrite
+
+=item write
+
+=item flush
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item newStream([OPTS])
+
+=item deflateParams
+
+=back
+
+=item Importing
+
+:all, :constants, :flush, :level, :strategy, :zip_method
+
+=item EXAMPLES
+
+=over 4
+
+=item Apache::GZip Revisited
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Dir - supply object methods for directory handles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+new ( [ DIRNAME ] ), open ( DIRNAME ), read (), seek ( POS ), tell (),
+rewind (), close (), tie %hash, 'IO::Dir', DIRNAME [, OPTIONS ]
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::File - supply object methods for filehandles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( FILENAME [,MODE [,PERMS]] ), new_tmpfile
+
+=item METHODS
+
+open( FILENAME [,MODE [,PERMS]] ), open( FILENAME, IOLAYERS ), binmode(
+[LAYER] )
+
+=item NOTE
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 IO::Handle - supply object methods for I/O handles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new (), new_from_fd ( FD, MODE )
+
+=item METHODS
+
+$io->fdopen ( FD, MODE ), $io->opened, $io->getline, $io->getlines,
+$io->ungetc ( ORD ), $io->write ( BUF, LEN [, OFFSET ] ), $io->error,
+$io->clearerr, $io->sync, $io->flush, $io->printflush ( ARGS ),
+$io->blocking ( [ BOOL ] ), $io->untaint
+
+=item NOTE
+
+=item SEE ALSO
+
+=item BUGS
+
+=item HISTORY
+
+=back
+
+=head2 IO::Pipe - supply object methods for pipes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [READER, WRITER] )
+
+=item METHODS
+
+reader ([ARGS]), writer ([ARGS]), handles ()
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Poll - Object interface to system poll call
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+mask ( IO [, EVENT_MASK ] ), poll ( [ TIMEOUT ] ), events ( IO ), remove (
+IO ), handles( [ EVENT_MASK ] )
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Seekable - supply seek based methods for I/O objects
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$io->getpos, $io->setpos, $io->seek ( POS, WHENCE ), WHENCE=0 (SEEK_SET),
+WHENCE=1 (SEEK_CUR), WHENCE=2 (SEEK_END), $io->sysseek( POS, WHENCE ),
+$io->tell
+
+=item SEE ALSO
+
+=item HISTORY
+
+=back
+
+=head2 IO::Select - OO interface to the select system call
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ HANDLES ] )
+
+=item METHODS
+
+add ( HANDLES ), remove ( HANDLES ), exists ( HANDLE ), handles, can_read (
+[ TIMEOUT ] ), can_write ( [ TIMEOUT ] ), has_exception ( [ TIMEOUT ] ),
+count (), bits(), select ( READ, WRITE, EXCEPTION [, TIMEOUT ] )
+
+=item EXAMPLE
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Socket - Object interface to socket communications
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ARGS] )
+
+=item METHODS
+
+accept([PKG]), socketpair(DOMAIN, TYPE, PROTOCOL), atmark, connected,
+protocol, sockdomain, sockopt(OPT [, VAL]), getsockopt(LEVEL, OPT),
+setsockopt(LEVEL, OPT, VAL), socktype, timeout([VAL])
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Socket::INET - Object interface for AF_INET domain sockets
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ARGS] )
+
+=over 4
+
+=item METHODS
+
+sockaddr (), sockport (), sockhost (), peeraddr (), peerport (), peerhost
+()
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Socket::UNIX - Object interface for AF_UNIX domain sockets
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ARGS] )
+
+=item METHODS
+
+hostpath(), peerpath()
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 IO::Uncompress::AnyInflate - Uncompress zlib-based (zip, gzip)
+file/buffer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+RFC 1950, RFC 1951 (optionally), gzip (RFC 1952), zip
+
+=item Functional Interface
+
+=over 4
+
+=item anyinflate $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>, C<< RawInflate => 0|1
+>>, C<< ParseExtra => 0|1 >> If the gzip FEXTRA header field is present and
+this option is set, it will force the module to check that it conforms to
+the sub-field structure as defined in RFC 1952
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item inflateSync
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::AnyUncompress - Uncompress gzip, zip, bzip2 or lzop
+file/buffer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+RFC 1950, RFC 1951 (optionally), gzip (RFC 1952), zip, bzip2, lzop, lzf,
+lzma, xz
+
+=item Functional Interface
+
+=over 4
+
+=item anyuncompress $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>, C<< RawInflate => 0|1
+>>, C<< UnLzma => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::Base - Base Class for IO::Uncompress modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::Bunzip2 - Read bzip2 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item bunzip2 $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>,
+C<< MultiStream => 0|1 >>, C<< TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>, C<< Small => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::Gunzip - Read RFC 1952 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item gunzip $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>, C<< ParseExtra => 0|1
+>> If the gzip FEXTRA header field is present and this option is set, it
+will force the module to check that it conforms to the sub-field structure
+as defined in RFC 1952
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item inflateSync
+
+=item getHeaderInfo
+
+Name, Comment
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::Inflate - Read RFC 1950 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item inflate $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item inflateSync
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::RawInflate - Read RFC 1951 files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item rawinflate $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item inflateSync
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Uncompress::Unzip - Read zip files/buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Functional Interface
+
+=over 4
+
+=item unzip $input => $output [, OPTS]
+
+A filename, A filehandle, A scalar reference, An array reference, An Input
+FileGlob string, A filename, A filehandle, A scalar reference, An Array
+Reference, An Output FileGlob
+
+=item Notes
+
+=item Optional Parameters
+
+C<< AutoClose => 0|1 >>, C<< BinModeOut => 0|1 >>, C<< Append => 0|1 >>, A
+Buffer, A Filename, A Filehandle, C<< MultiStream => 0|1 >>, C<<
+TrailingData => $scalar >>
+
+=item Examples
+
+=back
+
+=item OO Interface
+
+=over 4
+
+=item Constructor
+
+A filename, A filehandle, A scalar reference
+
+=item Constructor Options
+
+C<< AutoClose => 0|1 >>, C<< MultiStream => 0|1 >>, C<< Prime => $string
+>>, C<< Transparent => 0|1 >>, C<< BlockSize => $num >>, C<< InputLength =>
+$size >>, C<< Append => 0|1 >>, C<< Strict => 0|1 >>
+
+=item Examples
+
+=back
+
+=item Methods
+
+=over 4
+
+=item read
+
+=item read
+
+=item getline
+
+=item getc
+
+=item ungetc
+
+=item inflateSync
+
+=item getHeaderInfo
+
+=item tell
+
+=item eof
+
+=item seek
+
+=item binmode
+
+=item opened
+
+=item autoflush
+
+=item input_line_number
+
+=item fileno
+
+=item close
+
+=item nextStream
+
+=item trailingData
+
+=back
+
+=item Importing
+
+:all
+
+=item EXAMPLES
+
+=over 4
+
+=item Working with Net::FTP
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item MODIFICATION HISTORY
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 IO::Zlib - IO:: style interface to L<Compress::Zlib>
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ARGS] )
+
+=item OBJECT METHODS
+
+open ( FILENAME, MODE ), opened, close, getc, getline, getlines, print (
+ARGS... ), read ( BUF, NBYTES, [OFFSET] ), eof, seek ( OFFSET, WHENCE ),
+tell, setpos ( POS ), getpos ( POS )
+
+=item USING THE EXTERNAL GZIP
+
+=item CLASS METHODS
+
+has_Compress_Zlib, gzip_external, gzip_used, gzip_read_open,
+gzip_write_open
+
+=item DIAGNOSTICS
+
+IO::Zlib::getlines: must be called in list context,
+IO::Zlib::gzopen_external: mode '...' is illegal, IO::Zlib::import: '...'
+is illegal, IO::Zlib::import: ':gzip_external' requires an argument,
+IO::Zlib::import: 'gzip_read_open' requires an argument, IO::Zlib::import:
+'gzip_read' '...' is illegal, IO::Zlib::import: 'gzip_write_open' requires
+an argument, IO::Zlib::import: 'gzip_write_open' '...' is illegal,
+IO::Zlib::import: no Compress::Zlib and no external gzip, IO::Zlib::open:
+needs a filename, IO::Zlib::READ: NBYTES must be specified,
+IO::Zlib::WRITE: too long LENGTH
+
+=item SEE ALSO
+
+=item HISTORY
+
+=item COPYRIGHT
+
+=back
+
+=head2 IPC-Open2::lib::IPC::Open2, IPC::Open2 - open a process for both
+reading and writing using open2()
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item WARNING
+
+=item SEE ALSO
+
+=back
+
+=head2 IPC-Open3::lib::IPC::Open3, IPC::Open3 - open a process for reading,
+writing, and error handling using open3()
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item See Also
+
+L<IPC::Open2>, L<IPC::Run>
+
+=item WARNING
+
+=back
+
+=head2 IPC::Open2 - open a process for both reading and writing using
+open2()
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item WARNING
+
+=item SEE ALSO
+
+=back
+
+=head2 IPC::Open3 - open a process for reading, writing, and error handling
+using open3()
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item See Also
+
+L<IPC::Open2>, L<IPC::Run>
+
+=item WARNING
+
+=back
+
+=head2 IPCmd, IPC::Cmd - finding and running system commands made easy
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CLASS METHODS
+
+=over 4
+
+=item $ipc_run_version = IPC::Cmd->can_use_ipc_run( [VERBOSE] )
+
+=back
+
+=back
+
+=over 4
+
+=item $ipc_open3_version = IPC::Cmd->can_use_ipc_open3( [VERBOSE] )
+
+=back
+
+=over 4
+
+=item $bool = IPC::Cmd->can_capture_buffer
+
+=back
+
+=over 4
+
+=item $bool = IPC::Cmd->can_use_run_forked
+
+=back
+
+=over 4
+
+=item FUNCTIONS
+
+=over 4
+
+=item $path = can_run( PROGRAM );
+
+=back
+
+=back
+
+=over 4
+
+=item $ok | ($ok, $err, $full_buf, $stdout_buff, $stderr_buff) = run(
+command => COMMAND, [verbose => BOOL, buffer => \$SCALAR, timeout => DIGIT]
+);
+
+command, verbose, buffer, timeout, success, error message, full_buffer,
+out_buffer, error_buffer
+
+=back
+
+=over 4
+
+=item $hashref = run_forked( command => COMMAND, { child_stdin => SCALAR,
+timeout => DIGIT, stdout_handler => CODEREF, stderr_handler => CODEREF} );
+
+C<timeout>, C<child_stdin>, C<stdout_handler>, C<stderr_handler>,
+C<exit_code>, C<timeout>, C<stdout>, C<stderr>, C<merged>, C<err_msg>
+
+=back
+
+=over 4
+
+=item $q = QUOTE
+
+=back
+
+=over 4
+
+=item HOW IT WORKS
+
+=item Global Variables
+
+=over 4
+
+=item $IPC::Cmd::VERBOSE
+
+=item $IPC::Cmd::USE_IPC_RUN
+
+=item $IPC::Cmd::USE_IPC_OPEN3
+
+=item $IPC::Cmd::WARN
+
+=back
+
+=item Caveats
+
+Whitespace and IPC::Open3 / system(), Whitespace and IPC::Run, IO Redirect,
+Interleaving STDOUT/STDERR
+
+=item See Also
+
+=item ACKNOWLEDGEMENTS
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 List::Util - A selection of general-utility list subroutines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+first BLOCK LIST, max LIST, maxstr LIST, min LIST, minstr LIST, reduce
+BLOCK LIST, shuffle LIST, sum LIST
+
+=item KNOWN BUGS
+
+=item SUGGESTED ADDITIONS
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 List::Util::XS - Indicate if List::Util was compiled with a C
+compiler
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 Locale::Constants - constants for Locale codes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item KNOWN BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+Locale::Language, Locale::Country, Locale::Script, Locale::Currency
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Locale::Country - ISO codes for country identification (ISO 3166)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<alpha-2>, B<alpha-3>, B<numeric>
+
+=item CONVERSION ROUTINES
+
+code2country( CODE, [ CODESET ] ), country2code( STRING, [ CODESET ] ),
+country_code2code( CODE, CODESET, CODESET )
+
+=item QUERY ROUTINES
+
+C<all_country_codes( [ CODESET ] )>, C<all_country_names( [ CODESET ] )>
+
+=item SEMI-PRIVATE ROUTINES
+
+=over 4
+
+=item alias_code
+
+=item rename_country
+
+=back
+
+=item EXAMPLES
+
+=item DOMAIN NAMES
+
+=item KNOWN BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+Locale::Language, Locale::Script, Locale::Currency, Locale::SubCountry, ISO
+3166-1, http://www.iso.org/iso/en/prods-services/iso3166ma/index.html,
+http://www.egt.ie/standards/iso3166/iso3166-1-en.html,
+http://www.cia.gov/cia/publications/factbook/docs/app-d-1.html
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Locale::Currency - ISO three letter codes for currency
+identification (ISO 4217)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+XTS, XXX
+
+=item CONVERSION ROUTINES
+
+code2currency(), currency2code()
+
+=item QUERY ROUTINES
+
+C<all_currency_codes()>, C<all_currency_names()>
+
+=item EXAMPLES
+
+=item KNOWN BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+Locale::Country, Locale::Script, ISO 4217:1995,
+http://www.bsi-global.com/iso4217currency
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Locale::Language - ISO two letter codes for language identification
+(ISO 639)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONVERSION ROUTINES
+
+code2language(), language2code()
+
+=item QUERY ROUTINES
+
+C<all_language_codes()>, C<all_language_names()>
+
+=item EXAMPLES
+
+=item KNOWN BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+Locale::Country, Locale::Script, Locale::Currency, ISO 639:1988 (E/F),
+http://lcweb.loc.gov/standards/iso639-2/langhome.html
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Locale::Maketext - framework for localization
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item QUICK OVERVIEW
+
+=item METHODS
+
+=over 4
+
+=item Construction Methods
+
+=item The "maketext" Method
+
+$lh->fail_with I<or> $lh->fail_with(I<PARAM>), $lh->failure_handler_auto
+
+=item Utility Methods
+
+$language->quant($number, $singular), $language->quant($number, $singular,
+$plural), $language->quant($number, $singular, $plural, $negative),
+$language->numf($number), $language->sprintf($format, @items),
+$language->language_tag(), $language->encoding()
+
+=item Language Handle Attributes and Internals
+
+=back
+
+=item LANGUAGE CLASS HIERARCHIES
+
+=item ENTRIES IN EACH LEXICON
+
+=item BRACKET NOTATION
+
+=item AUTO LEXICONS
+
+=item CONTROLLING LOOKUP FAILURE
+
+=item HOW TO USE MAKETEXT
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMER
+
+=item AUTHOR
+
+=back
+
+=head2 Locale::Maketext::Simple - Simple interface to
+Locale::Maketext::Lexicon
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+=over 4
+
+=item Class
+
+=item Path
+
+=item Style
+
+=item Export
+
+=item Subclass
+
+=item Decode
+
+=item Encoding
+
+=back
+
+=back
+
+=over 4
+
+=item ACKNOWLEDGMENTS
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=over 4
+
+=item The "MIT" License
+
+=back
+
+=back
+
+=head2 Locale::Maketext::TPJ13 -- article about software localization
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Localization and Perl: gettext breaks, Maketext fixes
+
+=over 4
+
+=item A Localization Horror Story: It Could Happen To You
+
+=item The Linguistic View
+
+=item Breaking gettext
+
+=item Replacing gettext
+
+=item Buzzwords: Abstraction and Encapsulation
+
+=item Buzzword: Isomorphism
+
+=item Buzzword: Inheritance
+
+=item Buzzword: Concision
+
+=item The Devil in the Details
+
+=item The Proof in the Pudding: Localizing Web Sites
+
+=item References
+
+=back
+
+=back
+
+=head2 Locale::Script - ISO codes for script identification (ISO 15924)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<alpha-2>, B<alpha-3>, B<numeric>
+
+=over 4
+
+=item SPECIAL CODES
+
+=back
+
+=item CONVERSION ROUTINES
+
+code2script( CODE, [ CODESET ] ), script2code( STRING, [ CODESET ] ),
+script_code2code( CODE, CODESET, CODESET )
+
+=item QUERY ROUTINES
+
+C<all_script_codes ( [ CODESET ] )>, C<all_script_names ( [ CODESET ] )>
+
+=item EXAMPLES
+
+=item KNOWN BUGS AND LIMITATIONS
+
+=item SEE ALSO
+
+Locale::Language, Locale::Currency, Locale::Country, ISO 15924,
+http://www.evertype.com/standards/iso15924/
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Log::Message - A generic message storing mechanism;
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Hierarchy
+
+Log::Message, Log::Message::Item, Log::Message::Handlers,
+Log::Message::Config
+
+=item Options
+
+config, private, verbose, tag, level, remove, chrono
+
+=back
+
+=over 4
+
+=item Methods
+
+=over 4
+
+=item new
+
+=back
+
+=back
+
+=over 4
+
+=item store
+
+message, tag, level, extra
+
+=back
+
+=over 4
+
+=item retrieve
+
+tag, level, message, amount, chrono, remove
+
+=back
+
+=over 4
+
+=item first
+
+=back
+
+=over 4
+
+=item last
+
+=back
+
+=over 4
+
+=item flush
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item Acknowledgements
+
+=item COPYRIGHT
+
+=back
+
+=head2 Log::Message::Config - Configuration options for Log::Message
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item Acknowledgements
+
+=item COPYRIGHT
+
+=back
+
+=head2 Log::Message::Handlers - Message handlers for Log::Message
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Default Handlers
+
+=over 4
+
+=item log
+
+=back
+
+=back
+
+=over 4
+
+=item carp
+
+=back
+
+=over 4
+
+=item croak
+
+=back
+
+=over 4
+
+=item cluck
+
+=back
+
+=over 4
+
+=item confess
+
+=back
+
+=over 4
+
+=item die
+
+=back
+
+=over 4
+
+=item warn
+
+=back
+
+=over 4
+
+=item trace
+
+=back
+
+=over 4
+
+=item Custom Handlers
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item Acknowledgements
+
+=item COPYRIGHT
+
+=back
+
+=head2 Log::Message::Item - Message objects for Log::Message
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Methods and Accessors
+
+=over 4
+
+=item remove
+
+=item id
+
+=item when
+
+=item message
+
+=item level
+
+=item tag
+
+=item shortmess
+
+=item longmess
+
+=item parent
+
+=back
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item Acknowledgements
+
+=item COPYRIGHT
+
+=back
+
+=head2 Log::Message::Simple - Simplified interface to Log::Message
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item msg("message string" [,VERBOSE])
+
+=item debug("message string" [,VERBOSE])
+
+=item error("error string" [,VERBOSE])
+
+=back
+
+=back
+
+=over 4
+
+=item carp();
+
+=item croak();
+
+=item confess();
+
+=item cluck();
+
+=back
+
+=over 4
+
+=item CLASS METHODS
+
+=over 4
+
+=item Log::Message::Simple->stack()
+
+=item Log::Message::Simple->stack_as_string([TRACE])
+
+=item Log::Message::Simple->flush()
+
+=back
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+$ERROR_FH, $MSG_FH, $DEBUG_FH, $STACKTRACE_ON_ERROR
+
+=back
+
+=head2 MIME::Base64 - Encoding and decoding of base64 strings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+encode_base64($str), encode_base64($str, $eol);, decode_base64($str)
+
+=item DIAGNOSTICS
+
+Premature end of base64 data, Premature padding of base64 data, Wide
+character in subroutine entry
+
+=item EXAMPLES
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 MIME::QuotedPrint - Encoding and decoding of quoted-printable
+strings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+encode_qp($str), encode_qp($str, $eol), encode_qp($str, $eol, $binmode),
+decode_qp($str);
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Math::BigFloat - Arbitrary size floating point math package
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Canonical notation
+
+=item Output
+
+=item C<mantissa()>, C<exponent()> and C<parts()>
+
+=item Accuracy vs. Precision
+
+=item Rounding
+
+ffround ( +$scale ), ffround ( -$scale ), ffround ( 0 ), fround ( +$scale
+), fround ( -$scale ) and fround ( 0 )
+
+=back
+
+=item METHODS
+
+=over 4
+
+=item accuracy
+
+=item precision()
+
+=item bexp()
+
+=item bnok()
+
+=item bpi()
+
+=item bcos()
+
+=item bsin()
+
+=item batan2()
+
+=item batan()
+
+=item bmuladd()
+
+=back
+
+=item Autocreating constants
+
+=over 4
+
+=item Math library
+
+=item Using Math::BigInt::Lite
+
+=back
+
+=item EXPORTS
+
+=item BUGS
+
+=item CAVEATS
+
+stringify, bstr(), bdiv, brsft, Modifying and =, bpow, precision() vs.
+accuracy()
+
+=item SEE ALSO
+
+=item LICENSE
+
+=item AUTHORS
+
+=back
+
+=head2 Math::BigInt - Arbitrary size integer/float math package
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+Input, Output
+
+=item METHODS
+
+=over 4
+
+=item config()
+
+=item accuracy()
+
+=item precision()
+
+=item brsft()
+
+=item new()
+
+=item from_oct()
+
+=item from_hex()
+
+=item from_bin()
+
+=item bnan()
+
+=item bzero()
+
+=item binf()
+
+=item bone()
+
+=item is_one()/is_zero()/is_nan()/is_inf()
+
+=item is_pos()/is_neg()/is_positive()/is_negative()
+
+ $x->is_pos(); # true if > 0
+ $x->is_neg(); # true if < 0
+
+=item is_odd()/is_even()/is_int()
+
+=item bcmp()
+
+=item bacmp()
+
+=item sign()
+
+=item digit()
+
+=item bneg()
+
+=item babs()
+
+=item bnorm()
+
+=item bnot()
+
+=item binc()
+
+=item bdec()
+
+=item badd()
+
+=item bsub()
+
+=item bmul()
+
+=item bmuladd()
+
+=item bdiv()
+
+=item bmod()
+
+=item bmodinv()
+
+=item bmodpow()
+
+=item bpow()
+
+=item blog()
+
+=item bexp()
+
+=item bnok()
+
+=item bpi()
+
+=item bcos()
+
+=item bsin()
+
+=item batan2()
+
+=item batan()
+
+=item blsft()
+
+=item brsft()
+
+=item band()
+
+=item bior()
+
+=item bxor()
+
+=item bnot()
+
+=item bsqrt()
+
+=item broot()
+
+=item bfac()
+
+=item round()
+
+=item bround()
+
+=item bfround()
+
+=item bfloor()
+
+=item bceil()
+
+=item bgcd()
+
+=item blcm()
+
+=item exponent()
+
+=item mantissa()
+
+=item parts()
+
+=item copy()
+
+=item as_int()/as_number()
+
+=item bsstr()
+
+=item as_hex()
+
+=item as_bin()
+
+=item as_oct()
+
+=item numify()
+
+=item modify()
+
+=item upgrade()/downgrade()
+
+=item div_scale()
+
+=item round_mode()
+
+=back
+
+=item ACCURACY and PRECISION
+
+=over 4
+
+=item Precision P
+
+=item Accuracy A
+
+=item Fallback F
+
+=item Rounding mode R
+
+'trunc', 'even', 'odd', '+inf', '-inf', 'zero', 'common', Precision,
+Accuracy (significant digits), Setting/Accessing, Creating numbers, Usage,
+Precedence, Overriding globals, Local settings, Rounding, Default values,
+Remarks
+
+=back
+
+=item Infinity and Not a Number
+
+oct()/hex(), log(-inf), exp(), cos(), sin(), atan2()
+
+=item INTERNALS
+
+=over 4
+
+=item MATH LIBRARY
+
+=item SIGN
+
+=item mantissa(), exponent() and parts()
+
+=back
+
+=item EXAMPLES
+
+ use Math::BigInt;
+
+=item Autocreating constants
+
+=item PERFORMANCE
+
+=over 4
+
+=item Alternative math libraries
+
+=item SUBCLASSING
+
+=back
+
+=item Subclassing Math::BigInt
+
+=item UPGRADING
+
+=over 4
+
+=item Auto-upgrade
+
+bsqrt(), div(), blog(), bexp()
+
+=back
+
+=item EXPORTS
+
+=item CAVEATS
+
+bstr(), bsstr() and 'cmp', int(), length, bdiv, infinity handling,
+Modifying and =, bpow, Overloading -$x, Mixing different object types,
+bsqrt(), brsft()
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 Math::BigInt::Calc - Pure Perl module to support Math::BigInt
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item STORAGE
+
+=item METHODS
+
+=item WRAP YOUR OWN
+
+=item LICENSE
+
+This program is free software; you may redistribute it and/or modify it
+under
+the same terms as Perl itself.
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 Math::BigInt::CalcEmu - Emulate low-level math with BigInt code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item __emu_bxor
+
+=item __emu_band
+
+=item __emu_bior
+
+=back
+
+=item LICENSE
+
+This program is free software; you may redistribute it and/or modify it
+under
+the same terms as Perl itself.
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 Math::BigInt::FastCalc - Math::BigInt::Calc with some XS for more
+speed
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item STORAGE
+
+=item METHODS
+
+=item LICENSE
+
+This program is free software; you may redistribute it and/or modify it
+under
+the same terms as Perl itself.
+
+=item AUTHORS
+
+=item SEE ALSO
+
+=back
+
+=head2 Math::BigRat - Arbitrary big rational numbers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item MATH LIBRARY
+
+=back
+
+=item METHODS
+
+=over 4
+
+=item new()
+
+=item numerator()
+
+=item denominator()
+
+ $d = $x->denominator();
+
+=item parts()
+
+=item numify()
+
+=item as_int()/as_number()
+
+=item as_float()
+
+=item as_hex()
+
+=item as_bin()
+
+=item as_oct()
+
+=item from_hex()/from_bin()/from_oct()
+
+=item length()
+
+=item digit()
+
+=item bnorm()
+
+=item bfac()
+
+=item bround()/round()/bfround()
+
+=item bmod()
+
+=item bneg()
+
+=item is_one()
+
+=item is_zero()
+
+=item is_pos()/is_positive()
+
+=item is_neg()/is_negative()
+
+=item is_int()
+
+=item is_odd()
+
+=item is_even()
+
+=item bceil()
+
+=item bfloor()
+
+ $x->bfloor();
+
+=item bsqrt()
+
+ $x->bsqrt();
+
+=item broot()
+
+ $x->broot($n);
+
+=item badd()/bmul()/bsub()/bdiv()/bdec()/binc()
+
+=item copy()
+
+=item bstr()/bsstr()
+
+=item bacmp()/bcmp()
+
+=item blsft()/brsft()
+
+=item bpow()
+
+=item bexp()
+
+=item bnok()
+
+=item config()
+
+=item objectify()
+
+=back
+
+=item BUGS
+
+inf handling (partial), NaN handling (partial), rounding (not implemented
+except for bceil/bfloor), $x ** $y where $y is not an integer, bmod(),
+blog(), bmodinv() and bmodpow() (partial)
+
+=item LICENSE
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 Math::Complex - complex numbers and associated mathematical
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPERATIONS
+
+=item CREATION
+
+=item DISPLAYING
+
+=over 4
+
+=item CHANGED IN PERL 5.6
+
+=back
+
+=item USAGE
+
+=item CONSTANTS
+
+=over 4
+
+=item PI
+
+=item Inf
+
+=back
+
+=item ERRORS DUE TO DIVISION BY ZERO OR LOGARITHM OF ZERO
+
+=item ERRORS DUE TO INDIGESTIBLE ARGUMENTS
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item LICENSE
+
+=back
+
+=head2 Math::Trig - trigonometric functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item TRIGONOMETRIC FUNCTIONS
+
+B<tan>
+
+=over 4
+
+=item ERRORS DUE TO DIVISION BY ZERO
+
+=item SIMPLE (REAL) ARGUMENTS, COMPLEX RESULTS
+
+=back
+
+=item PLANE ANGLE CONVERSIONS
+
+deg2rad, grad2rad, rad2deg, grad2deg, deg2grad, rad2grad, rad2rad, deg2deg,
+grad2grad
+
+=item RADIAL COORDINATE CONVERSIONS
+
+=over 4
+
+=item COORDINATE SYSTEMS
+
+=item 3-D ANGLE CONVERSIONS
+
+cartesian_to_cylindrical, cartesian_to_spherical, cylindrical_to_cartesian,
+cylindrical_to_spherical, spherical_to_cartesian, spherical_to_cylindrical
+
+=back
+
+=item GREAT CIRCLE DISTANCES AND DIRECTIONS
+
+=over 4
+
+=item great_circle_distance
+
+=item great_circle_direction
+
+=item great_circle_bearing
+
+=item great_circle_destination
+
+=item great_circle_midpoint
+
+=item great_circle_waypoint
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item CAVEAT FOR GREAT CIRCLE FORMULAS
+
+=item Real-valued asin and acos
+
+asin_real, acos_real
+
+=back
+
+=item BUGS
+
+=item AUTHORS
+
+=item LICENSE
+
+=back
+
+=head2 Memoize - Make functions faster by trading space for time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item DETAILS
+
+=item OPTIONS
+
+=over 4
+
+=item INSTALL
+
+=item NORMALIZER
+
+=item C<SCALAR_CACHE>, C<LIST_CACHE>
+
+C<MEMORY>, C<HASH>, C<TIE>, C<FAULT>, C<MERGE>
+
+=back
+
+=item OTHER FACILITIES
+
+=over 4
+
+=item C<unmemoize>
+
+=item C<flush_cache>
+
+=back
+
+=item CAVEATS
+
+=item PERSISTENT CACHE SUPPORT
+
+=item EXPIRATION SUPPORT
+
+=item BUGS
+
+=item MAILING LIST
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=item THANK YOU
+
+=back
+
+=head2 Memoize::AnyDBM_File - glue to provide EXISTS for AnyDBM_File for
+Storable use
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Memoize::Expire - Plug-in module for automatic expiration of
+memoized values
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item INTERFACE
+
+ TIEHASH, EXISTS, STORE
+
+=item ALTERNATIVES
+
+=item CAVEATS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Memoize::ExpireFile - test for Memoize expiration semantics
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Memoize::ExpireTest - test for Memoize expiration semantics
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Memoize::NDBM_File - glue to provide EXISTS for NDBM_File for
+Storable use
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Memoize::SDBM_File - glue to provide EXISTS for SDBM_File for
+Storable use
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Memoize::Storable - store Memoized data in Storable database
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=head2 Module::Build - Build and install Perl modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item GUIDE TO DOCUMENTATION
+
+General Usage (L<Module::Build>), Authoring Reference
+(L<Module::Build::Authoring>), API Reference (L<Module::Build::API>),
+Cookbook (L<Module::Build::Cookbook>)
+
+=item ACTIONS
+
+build, clean, code, config_data, diff, dist, distcheck, distclean, distdir,
+distmeta, distsign, disttest, docs, fakeinstall, help, html, install,
+installdeps, manifest, manpages, pardist, ppd, ppmdist, prereq_data,
+prereq_report, pure_install, realclean, retest, skipcheck, test, testall,
+testcover, testdb, testpod, testpodcoverage, versioninstall
+
+=item OPTIONS
+
+=over 4
+
+=item Command Line Options
+
+quiet, verbose, cpan_client, use_rcfile, allow_mb_mismatch, debug
+
+=item Default Options File (F<.modulebuildrc>)
+
+=item Environment variables
+
+MODULEBUILDRC, PERL_MB_OPT
+
+=back
+
+=item INSTALL PATHS
+
+lib, arch, script, bin, bindoc, libdoc, binhtml, libhtml, installdirs,
+install_path, install_base, destdir, prefix
+
+=item MOTIVATIONS
+
++, +
+
+=item TO DO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::API - API Reference for Module Authors
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item CONSTRUCTORS
+
+current(), new(), add_to_cleanup, auto_configure_requires, auto_features,
+autosplit, build_class, build_requires, create_packlist, c_source,
+conflicts, create_license, create_makefile_pl, create_readme,
+dist_abstract, dist_author, dist_name, dist_version, dist_version_from,
+dynamic_config, extra_compiler_flags, extra_linker_flags, get_options,
+type, store, default, include_dirs, install_path, installdirs, license,
+apache, apache_1_1, artistic, artistic_2, bsd, gpl, lgpl, mit, mozilla,
+open_source, perl, restrictive, unrestricted, meta_add, meta_merge,
+module_name, needs_compiler, PL_files, pm_files, pod_files, recommends,
+recursive_test_files, requires, script_files, share_dir, sign, test_files,
+use_tap_harness, tap_harness_args, xs_files, new_from_context(%args),
+resume(), subclass(), add_property, C<default>, C<check>, property_error
+
+=item METHODS
+
+add_build_element($type), add_to_cleanup(@files), args(),
+autosplit_file($from, $to), base_dir(), build_requires(), can_action(
+$action ), cbuilder(), check_installed_status($module, $version),
+check_installed_version($module, $version), compare_versions($v1, $op,
+$v2), config($key), config($key, $value), config() [deprecated],
+config_data($name), config_data($name => $value), conflicts(),
+contains_pod($file) [deprecated], copy_if_modified(%parameters),
+create_build_script(), current_action(), depends_on(@actions),
+dir_contains($first_dir, $second_dir), dispatch($action, %args),
+dist_dir(), dist_name(), dist_version(), do_system($cmd, @args),
+feature($name), feature($name => $value), fix_shebang_line(@files),
+have_c_compiler(), install_base_relpaths(), install_base_relpaths($type),
+install_base_relpaths($type => $path), install_destination($type),
+install_path(), install_path($type), install_path($type => $path),
+install_types(), invoked_action(), notes(), notes($key), notes($key =>
+$value), orig_dir(), os_type(), is_vmsish(), is_windowsish(), is_unixish(),
+prefix_relpaths(), prefix_relpaths($installdirs),
+prefix_relpaths($installdirs, $type), prefix_relpaths($installdirs, $type
+=> $path), get_metadata(), prepare_metadata() [deprecated],
+prereq_failures(), prereq_data(), prereq_report(), prompt($message,
+$default), recommends(), requires(), rscan_dir($dir, $pattern),
+runtime_params(), runtime_params($key), script_files(),
+up_to_date($source_file, $derived_file), up_to_date(\@source_files,
+\@derived_files), y_n($message, $default)
+
+=item Autogenerated Accessors
+
+=back
+
+=item MODULE METADATA
+
+keywords, resources
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Authoring - Authoring Module::Build modules
+
+=over 4
+
+=item DESCRIPTION
+
+=item STRUCTURE
+
+=item SUBCLASSING
+
+=item PREREQUISITES
+
+=over 4
+
+=item Types of prerequisites
+
+configure_requires, build_requires, requires, recommends, conflicts
+
+=item Format of prerequisites
+
+=item XS Extensions
+
+=back
+
+=item SAVING CONFIGURATION INFORMATION
+
+=item STARTING MODULE DEVELOPMENT
+
+=item AUTOMATION
+
+=item MIGRATION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Base - Default methods for Module::Build
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Bundling - How to bundle Module::Build with a
+distribution
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUNDLING OTHER CONFIGURATION DEPENDENCIES
+
+=over 4
+
+=item WARNING -- How to Manage Dependency Chains
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Compat - Compatibility with ExtUtils::MakeMaker
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+create_makefile_pl($style, $build), traditional, small, passthrough
+(DEPRECATED), run_build_pl(args => \@ARGV), args, script, write_makefile(),
+makefile
+
+=item SCENARIOS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::ConfigData - Configuration for Module::Build
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+config($name), feature($name), set_config($name, $value),
+set_feature($name, $value), config_names(), feature_names(),
+auto_feature_names(), write()
+
+=item AUTHOR
+
+=back
+
+=head2 Module::Build::Cookbook - Examples of Module::Build Usage
+
+=over 4
+
+=item DESCRIPTION
+
+=item BASIC RECIPES
+
+=over 4
+
+=item Installing modules that use Module::Build
+
+=item Modifying Config.pm values
+
+=item Installing modules using the programmatic interface
+
+=item Installing to a temporary directory
+
+=item Installing to a non-standard directory
+
+=item Installing in the same location as ExtUtils::MakeMaker
+
+=item Running a single test file
+
+=back
+
+=item ADVANCED RECIPES
+
+=over 4
+
+=item Making a CPAN.pm-compatible distribution
+
+=item Changing the order of the build process
+
+=item Adding new file types to the build process
+
+=item Adding new elements to the install process
+
+=back
+
+=item EXAMPLES ON CPAN
+
+=over 4
+
+=item SVN-Notify-Mirror
+
+1. Using C<auto_features>, I check to see whether two optional modules are
+available - SVN::Notify::Config and Net::SSH;, 2. If the S::N::Config
+module is loaded, I automatically generate test files for it during Build
+(using the C<PL_files> property), 3. If the C<ssh_feature> is available, I
+ask if the user wishes to perform the ssh tests (since it requires a little
+preliminary setup);, 4. Only if the user has C<ssh_feature> and answers yes
+to the testing, do I generate a test file
+
+=item Modifying an action
+
+=item Adding an action
+
+=item Bundling Module::Build
+
+=back
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::ModuleInfo, ModuleInfo - Gather package and POD
+information from a perl module file
+
+=over 4
+
+=item DESCRIPTION
+
+new_from_file($filename, collect_pod => 1), new_from_module($module,
+collect_pod => 1, inc => \@dirs), name(), version($package), filename(),
+packages_inside(), pod_inside(), contains_pod(), pod($section),
+find_module_by_name($module, \@dirs), find_module_dir_by_name($module,
+\@dirs)
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Notes - Create persistent distribution configuration
+modules
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Notes, NOTES_NAME - Configuration for MODULE_NAME
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+config($name), feature($name), set_config($name, $value),
+set_feature($name, $value), config_names(), feature_names(),
+auto_feature_names(), write()
+
+=item AUTHOR
+
+=back
+
+=head2 Module::Build::PPMMaker - Perl Package Manager file creation
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::Amiga - Builder class for Amiga platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::Default - Stub class for unknown platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::EBCDIC - Builder class for EBCDIC platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::MPEiX - Builder class for MPEiX platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::MacOS - Builder class for MacOS platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden Methods
+
+new(), make_executable(), dispatch(), ACTION_realclean()
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::RiscOS - Builder class for RiscOS platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::Unix - Builder class for Unix platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::VMS - Builder class for VMS platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Overridden Methods
+
+_set_defaults
+
+=back
+
+=back
+
+cull_args
+
+manpage_separator
+
+prefixify
+
+_quote_args
+
+have_forkpipe
+
+_backticks
+
+find_command
+
+_maybe_command (override)
+
+do_system
+
+oneliner
+
+_infer_xs_spec
+
+rscan_dir
+
+dist_dir
+
+man3page_name
+
+expand_test_dir
+
+_detildefy
+
+find_perl_interpreter
+
+localize_file_path
+
+localize_dir_path
+
+ACTION_clean
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::VOS - Builder class for VOS platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::Windows - Builder class for Windows
+platforms
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::aix - Builder class for AIX platform
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::cygwin - Builder class for Cygwin platform
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::darwin - Builder class for Mac OS X
+platform
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Build::Platform::os2 - Builder class for OS/2 platform
+
+=over 4
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::CoreList - what modules shipped with versions of perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS API
+
+C<first_release( MODULE )>, C<first_release_by_date( MODULE )>,
+C<find_modules( REGEX, [ LIST OF PERLS ] )>, C<find_version( PERL_VERSION
+)>, C<is_deprecated( MODULE, PERL_VERSION )>, C<removed_from( MODULE )>,
+C<removed_from_by_date( MODULE )>
+
+=item DATA STRUCTURES
+
+C<%Module::CoreList::version>, C<%Module::CoreList::released>,
+C<%Module::CoreList::families>, C<%Module::CoreList::deprecated>,
+C<%Module::CoreList::upstream>, C<%Module::CoreList::bug_tracker>
+
+=item CAVEATS
+
+=item HISTORY
+
+=item AUTHOR
+
+=item LICENSE
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Load - runtime require of both modules and files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Rules
+
+=item Caveats
+
+=item ACKNOWLEDGEMENTS
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Module::Load::Conditional - Looking up module information / loading
+at runtime
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Methods
+
+=item $href = check_install( module => NAME [, version => VERSION, verbose
+=> BOOL ] );
+
+module, version, verbose, file, dir, version, uptodate
+
+=back
+
+=over 4
+
+=item $bool = can_load( modules => { NAME => VERSION [,NAME => VERSION] },
+[verbose => BOOL, nocache => BOOL] )
+
+modules, verbose, nocache
+
+=back
+
+=over 4
+
+=item @list = requires( MODULE );
+
+=back
+
+=over 4
+
+=item Global Variables
+
+=over 4
+
+=item $Module::Load::Conditional::VERBOSE
+
+=item $Module::Load::Conditional::FIND_VERSION
+
+=item $Module::Load::Conditional::CHECK_INC_HASH
+
+=item $Module::Load::Conditional::CACHE
+
+=item $Module::Load::Conditional::ERROR
+
+=item $Module::Load::Conditional::DEPRECATED
+
+=back
+
+=item See Also
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Module::Loaded - mark modules as loaded or unloaded
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item $bool = mark_as_loaded( PACKAGE );
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = mark_as_unloaded( PACKAGE );
+
+=back
+
+=over 4
+
+=item $loc = is_loaded( PACKAGE );
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Module::Pluggable - automatically give your module the ability to
+have plugins
+
+=over 4
+
+=item SYNOPSIS
+
+=item EXAMPLE
+
+=item DESCRIPTION
+
+=item ADVANCED USAGE
+
+=item INNER PACKAGES
+
+=item OPTIONS
+
+=over 4
+
+=item sub_name
+
+=item search_path
+
+=item search_dirs
+
+=item instantiate
+
+=item require
+
+=item inner
+
+=item only
+
+=item except
+
+=item package
+
+=item file_regex
+
+=item include_editor_junk
+
+=back
+
+=item METHODs
+
+=over 4
+
+=item search_path
+
+=back
+
+=item FUTURE PLANS
+
+=item AUTHOR
+
+=item COPYING
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Module::Pluggable::Object - automatically give your module the
+ability to have plugins
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OPTIONS
+
+=item AUTHOR
+
+=item COPYING
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 NDBM_File - Tied access to ndbm files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<O_RDONLY>, C<O_WRONLY>, C<O_RDWR>
+
+=item DIAGNOSTICS
+
+=over 4
+
+=item C<ndbm store returned -1, errno 22, key "..." at ...>
+
+=back
+
+=item BUGS AND WARNINGS
+
+=back
+
+=head2 NEXT - Provide a pseudo-class NEXT (et al) that allows method
+redispatch
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Enforcing redispatch
+
+=item Avoiding repetitions
+
+=item Invoking all versions of a method with a single call
+
+=item Using C<EVERY> methods
+
+=back
+
+=item AUTHOR
+
+=item BUGS AND IRRITATIONS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::Cmd - Network Command class (as used by FTP, SMTP etc)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USER METHODS
+
+debug ( VALUE ), message (), code (), ok (), status (), datasend ( DATA ),
+dataend ()
+
+=item CLASS METHODS
+
+debug_print ( DIR, TEXT ), debug_text ( TEXT ), command ( CMD [, ARGS, ...
+]), unsupported (), response (), parse_response ( TEXT ), getline (),
+ungetline ( TEXT ), rawdatasend ( DATA ), read_until_dot (), tied_fh ()
+
+=item EXPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::Config - Local configuration data for libnet
+
+=over 4
+
+=item SYNOPSYS
+
+=item DESCRIPTION
+
+=item METHODS
+
+requires_firewall HOST
+
+=item NetConfig VALUES
+
+nntp_hosts, snpp_hosts, pop3_hosts, smtp_hosts, ph_hosts, daytime_hosts,
+time_hosts, inet_domain, ftp_firewall, ftp_firewall_type, ftp_ext_passive,
+ftp_int_passive, local_netmask, test_hosts, test_exists
+
+=back
+
+=head2 Net::Domain - Attempt to evaluate the current host's internet name
+and domain
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+hostfqdn (), domainname (), hostname (), hostdomain ()
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::FTP - FTP Client class
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OVERVIEW
+
+=item CONSTRUCTOR
+
+new ([ HOST ] [, OPTIONS ])
+
+=item METHODS
+
+login ([LOGIN [,PASSWORD [, ACCOUNT] ] ]), authorize ( [AUTH [, RESP]]),
+site (ARGS), ascii, binary, rename ( OLDNAME, NEWNAME ), delete ( FILENAME
+), cwd ( [ DIR ] ), cdup (), pwd (), restart ( WHERE ), rmdir ( DIR [,
+RECURSE ]), mkdir ( DIR [, RECURSE ]), alloc ( SIZE [, RECORD_SIZE] ), ls (
+[ DIR ] ), dir ( [ DIR ] ), get ( REMOTE_FILE [, LOCAL_FILE [, WHERE]] ),
+put ( LOCAL_FILE [, REMOTE_FILE ] ), put_unique ( LOCAL_FILE [, REMOTE_FILE
+] ), append ( LOCAL_FILE [, REMOTE_FILE ] ), unique_name (), mdtm ( FILE ),
+size ( FILE ), supported ( CMD ), hash ( [FILEHANDLE_GLOB_REF],[
+BYTES_PER_HASH_MARK] ), feature ( NAME ), nlst ( [ DIR ] ), list ( [ DIR ]
+), retr ( FILE ), stor ( FILE ), stou ( FILE ), appe ( FILE ), port ( [
+PORT ] ), pasv (), pasv_xfer ( SRC_FILE, DEST_SERVER [, DEST_FILE ] ),
+pasv_xfer_unique ( SRC_FILE, DEST_SERVER [, DEST_FILE ] ), pasv_wait (
+NON_PASV_SERVER ), abort (), quit ()
+
+=over 4
+
+=item Methods for the adventurous
+
+quot (CMD [,ARGS])
+
+=back
+
+=item THE dataconn CLASS
+
+read ( BUFFER, SIZE [, TIMEOUT ] ), write ( BUFFER, SIZE [, TIMEOUT ] ),
+bytes_read (), abort (), close ()
+
+=item UNIMPLEMENTED
+
+B<SMNT>, B<HELP>, B<MODE>, B<SYST>, B<STAT>, B<STRU>, B<REIN>
+
+=item REPORTING BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item USE EXAMPLES
+
+http://www.csh.rit.edu/~adam/Progs/
+
+=item CREDITS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::NNTP - NNTP Client class
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ HOST ] [, OPTIONS ])
+
+=item METHODS
+
+article ( [ MSGID|MSGNUM ], [FH] ), body ( [ MSGID|MSGNUM ], [FH] ), head (
+[ MSGID|MSGNUM ], [FH] ), articlefh ( [ MSGID|MSGNUM ] ), bodyfh ( [
+MSGID|MSGNUM ] ), headfh ( [ MSGID|MSGNUM ] ), nntpstat ( [ MSGID|MSGNUM ]
+), group ( [ GROUP ] ), ihave ( MSGID [, MESSAGE ]), last (), date (),
+postok (), authinfo ( USER, PASS ), list (), newgroups ( SINCE [,
+DISTRIBUTIONS ]), newnews ( SINCE [, GROUPS [, DISTRIBUTIONS ]]), next (),
+post ( [ MESSAGE ] ), postfh (), slave (), quit ()
+
+=over 4
+
+=item Extension methods
+
+newsgroups ( [ PATTERN ] ), distributions (), subscriptions (),
+overview_fmt (), active_times (), active ( [ PATTERN ] ), xgtitle ( PATTERN
+), xhdr ( HEADER, MESSAGE-SPEC ), xover ( MESSAGE-SPEC ), xpath (
+MESSAGE-ID ), xpat ( HEADER, PATTERN, MESSAGE-SPEC), xrover, listgroup ( [
+GROUP ] ), reader
+
+=back
+
+=item UNSUPPORTED
+
+=item DEFINITIONS
+
+MESSAGE-SPEC, PATTERN, Examples, C<[^]-]>, C<*bdc>, C<[0-9a-zA-Z]>, C<a??d>
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::POP3 - Post Office Protocol 3 Client class (RFC1939)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+new ( [ HOST ] [, OPTIONS ] 0
+
+=item METHODS
+
+auth ( USERNAME, PASSWORD ), user ( USER ), pass ( PASS ), login ( [ USER
+[, PASS ]] ), apop ( [ USER [, PASS ]] ), banner (), capa (), capabilities
+(), top ( MSGNUM [, NUMLINES ] ), list ( [ MSGNUM ] ), get ( MSGNUM [, FH ]
+), getfh ( MSGNUM ), last (), popstat (), ping ( USER ), uidl ( [ MSGNUM ]
+), delete ( MSGNUM ), reset (), quit ()
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::Ping - check a remote host for reachability
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Functions
+
+Net::Ping->new([$proto [, $def_timeout [, $bytes [, $device [, $tos
+]]]]]);, $p->ping($host [, $timeout]);, $p->source_verify( { 0 | 1 } );,
+$p->service_check( { 0 | 1 } );, $p->tcp_service_check( { 0 | 1 } );,
+$p->hires( { 0 | 1 } );, $p->bind($local_addr);, $p->open($host);, $p->ack(
+[ $host ] );, $p->nack( $failed_ack_host );, $p->close();,
+$p->port_number([$port_number]), pingecho($host [, $timeout]);
+
+=back
+
+=item NOTES
+
+=item INSTALL
+
+=item BUGS
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::SMTP - Simple Mail Transfer Protocol Client
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item CONSTRUCTOR
+
+new ( [ HOST ] [, OPTIONS ] )
+
+=item METHODS
+
+banner (), domain (), hello ( DOMAIN ), host (), etrn ( DOMAIN ), auth (
+USERNAME, PASSWORD ), mail ( ADDRESS [, OPTIONS] ), send ( ADDRESS ),
+send_or_mail ( ADDRESS ), send_and_mail ( ADDRESS ), reset (), recipient (
+ADDRESS [, ADDRESS, [...]] [, OPTIONS ] ), to ( ADDRESS [, ADDRESS [...]]
+), cc ( ADDRESS [, ADDRESS [...]] ), bcc ( ADDRESS [, ADDRESS [...]] ),
+data ( [ DATA ] ), expand ( ADDRESS ), verify ( ADDRESS ), help ( [
+$subject ] ), quit ()
+
+=item ADDRESSES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::Time - time and daytime network client interface
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+inet_time ( [HOST [, PROTOCOL [, TIMEOUT]]]), inet_daytime ( [HOST [,
+PROTOCOL [, TIMEOUT]]])
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Net::hostent - by-name interface to Perl's built-in gethost*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Net::libnetFAQ, libnetFAQ - libnet Frequently Asked Questions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Where to get this document
+
+=item How to contribute to this document
+
+=back
+
+=item Author and Copyright Information
+
+=over 4
+
+=item Disclaimer
+
+=back
+
+=item Obtaining and installing libnet
+
+=over 4
+
+=item What is libnet ?
+
+=item Which version of perl do I need ?
+
+=item What other modules do I need ?
+
+=item What machines support libnet ?
+
+=item Where can I get the latest libnet release
+
+=back
+
+=item Using Net::FTP
+
+=over 4
+
+=item How do I download files from an FTP server ?
+
+=item How do I transfer files in binary mode ?
+
+=item How can I get the size of a file on a remote FTP server ?
+
+=item How can I get the modification time of a file on a remote FTP server
+?
+
+=item How can I change the permissions of a file on a remote server ?
+
+=item Can I do a reget operation like the ftp command ?
+
+=item How do I get a directory listing from an FTP server ?
+
+=item Changing directory to "" does not fail ?
+
+=item I am behind a SOCKS firewall, but the Firewall option does not work ?
+
+=item I am behind an FTP proxy firewall, but cannot access machines outside
+?
+
+=item My ftp proxy firewall does not listen on port 21
+
+=item Is it possible to change the file permissions of a file on an FTP
+server ?
+
+=item I have seen scripts call a method message, but cannot find it
+documented ?
+
+=item Why does Net::FTP not implement mput and mget methods
+
+=back
+
+=item Using Net::SMTP
+
+=over 4
+
+=item Why can't the part of an Email address after the @ be used as the
+hostname ?
+
+=item Why does Net::SMTP not do DNS MX lookups ?
+
+=item The verify method always returns true ?
+
+=back
+
+=item Debugging scripts
+
+=over 4
+
+=item How can I debug my scripts that use Net::* modules ?
+
+=back
+
+=item AUTHOR AND COPYRIGHT
+
+=back
+
+=head2 Net::netent - by-name interface to Perl's built-in getnet*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Net::protoent - by-name interface to Perl's built-in getproto*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Net::servent - by-name interface to Perl's built-in getserv*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Netrc, Net::Netrc - OO interface to users netrc file
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item THE .netrc FILE
+
+machine name, default, login name, password string, account string, macdef
+name
+
+=item CONSTRUCTOR
+
+lookup ( MACHINE [, LOGIN ])
+
+=item METHODS
+
+login (), password (), account (), lpa ()
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 O - Generic interface to Perl Compiler backends
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONVENTIONS
+
+=item IMPLEMENTATION
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 ODBM_File - Tied access to odbm files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<O_RDONLY>, C<O_WRONLY>, C<O_RDWR>
+
+=item DIAGNOSTICS
+
+=over 4
+
+=item C<odbm store returned -1, errno 22, key "..." at ...>
+
+=back
+
+=item BUGS AND WARNINGS
+
+=back
+
+=head2 Object::Accessor - interface to create per object accessors
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item $object = Object::Accessor->new( [ARGS] );
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $object->mk_accessors( @ACCESSORS | \%ACCESSOR_MAP );
+
+=back
+
+=over 4
+
+=item @list = $self->ls_accessors;
+
+=back
+
+=over 4
+
+=item $ref = $self->ls_allow(KEY)
+
+=back
+
+=over 4
+
+=item $bool = $self->mk_aliases( alias => method, [alias2 => method2, ...]
+);
+
+=back
+
+=over 4
+
+=item $clone = $self->mk_clone;
+
+=back
+
+=over 4
+
+=item $bool = $self->mk_flush;
+
+=back
+
+=over 4
+
+=item $bool = $self->mk_verify;
+
+=back
+
+=over 4
+
+=item $bool = $self->register_callback( sub { ... } );
+
+=back
+
+=over 4
+
+=item $bool = $self->can( METHOD_NAME )
+
+=back
+
+=over 4
+
+=item $val = $self->___get( METHOD_NAME );
+
+=back
+
+=over 4
+
+=item $bool = $self->___set( METHOD_NAME => VALUE );
+
+=back
+
+=over 4
+
+=item $bool = $self->___alias( ALIAS => METHOD );
+
+=back
+
+=over 4
+
+=item LVALUE ACCESSORS
+
+=over 4
+
+=item CAVEATS
+
+Allow handlers, Callbacks
+
+=back
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Object::Accessor::FATAL
+
+=item $Object::Accessor::DEBUG
+
+=back
+
+=item TODO
+
+=over 4
+
+=item Create read-only accessors
+
+=back
+
+=item CAVEATS
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Opcode - Disable named opcodes when compiling perl code
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item WARNING
+
+=item Operator Names and Operator Lists
+
+an operator name (opname), an operator tag name (optag), a negated opname
+or optag, an operator set (opset)
+
+=item Opcode Functions
+
+opcodes, opset (OP, ...), opset_to_ops (OPSET), opset_to_hex (OPSET),
+full_opset, empty_opset, invert_opset (OPSET), verify_opset (OPSET, ...),
+define_optag (OPTAG, OPSET), opmask_add (OPSET), opmask, opdesc (OP, ...),
+opdump (PAT)
+
+=item Manipulating Opsets
+
+=item TO DO (maybe)
+
+=back
+
+=over 4
+
+=item Predefined Opcode Tags
+
+:base_core, :base_mem, :base_loop, :base_io, :base_orig, :base_math,
+:base_thread, :default, :filesys_read, :sys_db, :browse, :filesys_open,
+:filesys_write, :subprocess, :ownprocess, :others, :load,
+:still_to_be_decided, :dangerous
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=back
+
+=head2 Opcode::ops, ops - Perl pragma to restrict unsafe operations when
+compiling
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 POSIX - Perl interface to IEEE Std 1003.1
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item CAVEATS
+
+=item FUNCTIONS
+
+_exit, abort, abs, access, acos, alarm, asctime, asin, assert, atan, atan2,
+atexit, atof, atoi, atol, bsearch, calloc, ceil, chdir, chmod, chown,
+clearerr, clock, close, closedir, cos, cosh, creat, ctermid, ctime,
+cuserid, difftime, div, dup, dup2, errno, execl, execle, execlp, execv,
+execve, execvp, exit, exp, fabs, fclose, fcntl, fdopen, feof, ferror,
+fflush, fgetc, fgetpos, fgets, fileno, floor, fmod, fopen, fork, fpathconf,
+fprintf, fputc, fputs, fread, free, freopen, frexp, fscanf, fseek, fsetpos,
+fstat, fsync, ftell, fwrite, getc, getchar, getcwd, getegid, getenv,
+geteuid, getgid, getgrgid, getgrnam, getgroups, getlogin, getpgrp, getpid,
+getppid, getpwnam, getpwuid, gets, getuid, gmtime, isalnum, isalpha,
+isatty, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace,
+isupper, isxdigit, kill, labs, lchown, ldexp, ldiv, link, localeconv,
+localtime, log, log10, longjmp, lseek, malloc, mblen, mbstowcs, mbtowc,
+memchr, memcmp, memcpy, memmove, memset, mkdir, mkfifo, mktime, modf, nice,
+offsetof, open, opendir, pathconf, pause, perror, pipe, pow, printf, putc,
+putchar, puts, qsort, raise, rand, read, readdir, realloc, remove, rename,
+rewind, rewinddir, rmdir, scanf, setgid, setjmp, setlocale, setpgid,
+setsid, setuid, sigaction, siglongjmp, sigpending, sigprocmask, sigsetjmp,
+sigsuspend, sin, sinh, sleep, sprintf, sqrt, srand, sscanf, stat, strcat,
+strchr, strcmp, strcoll, strcpy, strcspn, strerror, strftime, strlen,
+strncat, strncmp, strncpy, strpbrk, strrchr, strspn, strstr, strtod,
+strtok, strtol, strtoul, strxfrm, sysconf, system, tan, tanh, tcdrain,
+tcflow, tcflush, tcgetpgrp, tcsendbreak, tcsetpgrp, time, times, tmpfile,
+tmpnam, tolower, toupper, ttyname, tzname, tzset, umask, uname, ungetc,
+unlink, utime, vfprintf, vprintf, vsprintf, wait, waitpid, wcstombs,
+wctomb, write
+
+=item CLASSES
+
+=over 4
+
+=item POSIX::SigAction
+
+new, handler, mask, flags, safe
+
+=item POSIX::SigRt
+
+%SIGRT, SIGRTMIN, SIGRTMAX
+
+=item POSIX::SigSet
+
+new, addset, delset, emptyset, fillset, ismember
+
+=item POSIX::Termios
+
+new, getattr, getcc, getcflag, getiflag, getispeed, getlflag, getoflag,
+getospeed, setattr, setcc, setcflag, setiflag, setispeed, setlflag,
+setoflag, setospeed, Baud rate values, Terminal interface values, c_cc
+field values, c_cflag field values, c_iflag field values, c_lflag field
+values, c_oflag field values
+
+=back
+
+=item PATHNAME CONSTANTS
+
+Constants
+
+=item POSIX CONSTANTS
+
+Constants
+
+=item SYSTEM CONFIGURATION
+
+Constants
+
+=item ERRNO
+
+Constants
+
+=item FCNTL
+
+Constants
+
+=item FLOAT
+
+Constants
+
+=item LIMITS
+
+Constants
+
+=item LOCALE
+
+Constants
+
+=item MATH
+
+Constants
+
+=item SIGNAL
+
+Constants
+
+=item STAT
+
+Constants, Macros
+
+=item STDLIB
+
+Constants
+
+=item STDIO
+
+Constants
+
+=item TIME
+
+Constants
+
+=item UNISTD
+
+Constants
+
+=item WAIT
+
+Constants, WNOHANG, WUNTRACED, Macros, WIFEXITED, WEXITSTATUS, WIFSIGNALED,
+WTERMSIG, WIFSTOPPED, WSTOPSIG
+
+=back
+
+=head2 Package::Constants - List all constants declared in a package
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CLASS METHODS
+
+=over 4
+
+=item @const = Package::Constants->list( PACKAGE_NAME );
+
+=back
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Package::Constants::DEBUG
+
+=back
+
+=back
+
+=over 4
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Params::Check - A generic input parsing/checking mechanism.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Template
+
+default, required, strict_type, defined, no_override, store, allow
+
+=item Functions
+
+=over 4
+
+=item check( \%tmpl, \%args, [$verbose] );
+
+Template, Arguments, Verbose
+
+=back
+
+=back
+
+=over 4
+
+=item allow( $test_me, \@criteria );
+
+string, regexp, subroutine, array ref
+
+=back
+
+=over 4
+
+=item last_error()
+
+=back
+
+=over 4
+
+=item Global Variables
+
+=over 4
+
+=item $Params::Check::VERBOSE
+
+=item $Params::Check::STRICT_TYPE
+
+=item $Params::Check::ALLOW_UNKNOWN
+
+=item $Params::Check::STRIP_LEADING_DASHES
+
+=item $Params::Check::NO_DUPLICATES
+
+=item $Params::Check::PRESERVE_CASE
+
+=item $Params::Check::ONLY_ALLOW_DEFINED
+
+=item $Params::Check::SANITY_CHECK_TEMPLATE
+
+=item $Params::Check::WARNINGS_FATAL
+
+=item $Params::Check::CALLER_DEPTH
+
+=back
+
+=item AUTHOR
+
+=item Acknowledgements
+
+=item COPYRIGHT
+
+=back
+
+=head2 Parse::CPAN::Meta - Parse META.yml and other similar CPAN metadata
+files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item Load
+
+=item LoadFile
+
+=back
+
+=item SUPPORT
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 PerlIO - On demand loader for PerlIO layers and root of PerlIO::*
+name space
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+:unix, :stdio, :perlio, :crlf, :mmap, :utf8, :bytes, :raw, :pop, :win32
+
+=over 4
+
+=item Custom Layers
+
+:encoding, :via
+
+=item Alternatives to raw
+
+=item Defaults and how to override them
+
+=item Querying the layers of filehandles
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 PerlIO-encoding, PerlIO::encoding - encoding layer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 PerlIO-scalar, PerlIO::scalar - in-memory IO, scalar IO
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item IMPLEMENTATION NOTE
+
+=back
+
+=head2 PerlIO-via, PerlIO::via - Helper class for PerlIO layers implemented
+in perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXPECTED METHODS
+
+$class->PUSHED([$mode,[$fh]]), $obj->POPPED([$fh]),
+$obj->UTF8($bellowFlag,[$fh]), $obj->OPEN($path,$mode,[$fh]),
+$obj->BINMODE([$fh]), $obj->FDOPEN($fd,[$fh]),
+$obj->SYSOPEN($path,$imode,$perm,[$fh]), $obj->FILENO($fh),
+$obj->READ($buffer,$len,$fh), $obj->WRITE($buffer,$fh), $obj->FILL($fh),
+$obj->CLOSE($fh), $obj->SEEK($posn,$whence,$fh), $obj->TELL($fh),
+$obj->UNREAD($buffer,$fh), $obj->FLUSH($fh), $obj->SETLINEBUF($fh),
+$obj->CLEARERR($fh), $obj->ERROR($fh), $obj->EOF($fh)
+
+=item EXAMPLES
+
+=over 4
+
+=item Example - a Hexadecimal Handle
+
+=back
+
+=back
+
+=head2 PerlIO::encoding - encoding layer
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 PerlIO::scalar - in-memory IO, scalar IO
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item IMPLEMENTATION NOTE
+
+=back
+
+=head2 PerlIO::via - Helper class for PerlIO layers implemented in perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXPECTED METHODS
+
+$class->PUSHED([$mode,[$fh]]), $obj->POPPED([$fh]),
+$obj->UTF8($bellowFlag,[$fh]), $obj->OPEN($path,$mode,[$fh]),
+$obj->BINMODE([$fh]), $obj->FDOPEN($fd,[$fh]),
+$obj->SYSOPEN($path,$imode,$perm,[$fh]), $obj->FILENO($fh),
+$obj->READ($buffer,$len,$fh), $obj->WRITE($buffer,$fh), $obj->FILL($fh),
+$obj->CLOSE($fh), $obj->SEEK($posn,$whence,$fh), $obj->TELL($fh),
+$obj->UNREAD($buffer,$fh), $obj->FLUSH($fh), $obj->SETLINEBUF($fh),
+$obj->CLEARERR($fh), $obj->ERROR($fh), $obj->EOF($fh)
+
+=item EXAMPLES
+
+=over 4
+
+=item Example - a Hexadecimal Handle
+
+=back
+
+=back
+
+=head2 PerlIO::via::QuotedPrint - PerlIO layer for quoted-printable strings
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item REQUIRED MODULES
+
+=item SEE ALSO
+
+=item ACKNOWLEDGEMENTS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Pod::Checker, podchecker() - check pod documents for syntax errors
+
+=over 4
+
+=item SYNOPSIS
+
+=item OPTIONS/ARGUMENTS
+
+=over 4
+
+=item podchecker()
+
+B<-warnings> =E<gt> I<val>
+
+=back
+
+=item DESCRIPTION
+
+=item DIAGNOSTICS
+
+=over 4
+
+=item Errors
+
+empty =headn, =over on line I<N> without closing =back, =item without
+previous =over, =back without previous =over, No argument for =begin, =end
+without =begin, Nested =begin's, =for without formatter specification,
+unresolved internal link I<NAME>, Unknown command "I<CMD>", Unknown
+interior-sequence "I<SEQ>", nested commands
+I<CMD>E<lt>...I<CMD>E<lt>...E<gt>...E<gt>, garbled entity I<STRING>, Entity
+number out of range, malformed link LE<lt>E<gt>, nonempty ZE<lt>E<gt>,
+empty XE<lt>E<gt>, Spurious text after =pod / =cut, Spurious character(s)
+after =back
+
+=item Warnings
+
+multiple occurrence of link target I<name>, line containing nothing but
+whitespace in paragraph, file does not start with =head, previous =item has
+no contents, preceding non-item paragraph(s), =item type mismatch (I<one>
+vs. I<two>), I<N> unescaped C<E<lt>E<gt>> in paragraph, Unknown entity, No
+items in =over, No argument for =item, empty section in previous paragraph,
+Verbatim paragraph in NAME section, =headI<n> without preceding higher
+level
+
+=item Hyperlinks
+
+ignoring leading/trailing whitespace in link, (section) in '$page'
+deprecated, alternative text/node '%s' contains non-escaped | or /
+
+=back
+
+=item RETURN VALUE
+
+=item EXAMPLES
+
+=item INTERFACE
+
+=back
+
+C<Pod::Checker-E<gt>new( %options )>
+
+C<$checker-E<gt>poderror( @args )>, C<$checker-E<gt>poderror( {%opts},
+@args )>
+
+C<$checker-E<gt>num_errors()>
+
+C<$checker-E<gt>num_warnings()>
+
+C<$checker-E<gt>name()>
+
+C<$checker-E<gt>node()>
+
+C<$checker-E<gt>idx()>
+
+C<$checker-E<gt>hyperlink()>
+
+=over 4
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Escapes -- for resolving Pod EE<lt>...E<gt> sequences
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item GOODIES
+
+e2char($e_content), e2charnum($e_content), $Name2character{I<name>},
+$Name2character_number{I<name>}, $Latin1Code_to_fallback{I<integer>},
+$Latin1Char_to_fallback{I<character>}, $Code2USASCII{I<integer>}
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Find - find POD documents in directory trees
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item C<pod_find( { %opts } , @directories )>
+
+C<-verbose =E<gt> 1>, C<-perl =E<gt> 1>, C<-script =E<gt> 1>, C<-inc =E<gt>
+1>
+
+=back
+
+=over 4
+
+=item C<simplify_name( $str )>
+
+=back
+
+=over 4
+
+=item C<pod_where( { %opts }, $pod )>
+
+C<-inc =E<gt> 1>, C<-dirs =E<gt> [ $dir1, $dir2, ... ]>, C<-verbose =E<gt>
+1>
+
+=back
+
+=over 4
+
+=item C<contains_pod( $file , $verbose )>
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Pod::Html - module to convert pod files to HTML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item pod2html
+
+backlink, cachedir, css, flush, header, help, hiddendirs, htmldir,
+htmlroot, index, infile, libpods, netscape, outfile, podpath, podroot,
+quiet, recurse, title, verbose
+
+=item htmlify
+
+=item anchorify
+
+=back
+
+=item ENVIRONMENT
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 Pod::InputObjects - objects representing POD input paragraphs,
+commands, etc.
+
+=over 4
+
+=item SYNOPSIS
+
+=item REQUIRES
+
+=item EXPORTS
+
+=item DESCRIPTION
+
+package B<Pod::InputSource>, package B<Pod::Paragraph>, package
+B<Pod::InteriorSequence>, package B<Pod::ParseTree>
+
+=back
+
+=over 4
+
+=item B<Pod::InputSource>
+
+=back
+
+=over 4
+
+=item B<new()>
+
+=back
+
+=over 4
+
+=item B<name()>
+
+=back
+
+=over 4
+
+=item B<handle()>
+
+=back
+
+=over 4
+
+=item B<was_cutting()>
+
+=back
+
+=over 4
+
+=item B<Pod::Paragraph>
+
+=back
+
+=over 4
+
+=item Pod::Paragraph-E<gt>B<new()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<cmd_name()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<text()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<raw_text()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<cmd_prefix()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<cmd_separator()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<parse_tree()>
+
+=back
+
+=over 4
+
+=item $pod_para-E<gt>B<file_line()>
+
+=back
+
+=over 4
+
+=item B<Pod::InteriorSequence>
+
+=back
+
+=over 4
+
+=item Pod::InteriorSequence-E<gt>B<new()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<cmd_name()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<prepend()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<append()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<nested()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<raw_text()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<left_delimiter()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<right_delimiter()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<parse_tree()>
+
+=back
+
+=over 4
+
+=item $pod_seq-E<gt>B<file_line()>
+
+=back
+
+=over 4
+
+=item Pod::InteriorSequence::B<DESTROY()>
+
+=back
+
+=over 4
+
+=item B<Pod::ParseTree>
+
+=back
+
+=over 4
+
+=item Pod::ParseTree-E<gt>B<new()>
+
+=back
+
+=over 4
+
+=item $ptree-E<gt>B<top()>
+
+=back
+
+=over 4
+
+=item $ptree-E<gt>B<children()>
+
+=back
+
+=over 4
+
+=item $ptree-E<gt>B<prepend()>
+
+=back
+
+=over 4
+
+=item $ptree-E<gt>B<append()>
+
+=back
+
+=over 4
+
+=item $ptree-E<gt>B<raw_text()>
+
+=back
+
+=over 4
+
+=item Pod::ParseTree::B<DESTROY()>
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::LaTeX - Convert Pod data to formatted Latex
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item OBJECT METHODS
+
+C<initialize>
+
+=back
+
+=over 4
+
+=item Data Accessors
+
+B<AddPreamble>
+
+=back
+
+B<AddPostamble>
+
+B<Head1Level>
+
+B<Label>
+
+B<LevelNoNum>
+
+B<MakeIndex>
+
+B<ReplaceNAMEwithSection>
+
+B<StartWithNewPage>
+
+B<TableOfContents>
+
+B<UniqueLabels>
+
+B<UserPreamble>
+
+B<UserPostamble>
+
+B<Lists>
+
+=over 4
+
+=item Subclassed methods
+
+=back
+
+B<begin_pod>
+
+B<end_pod>
+
+B<command>
+
+B<verbatim>
+
+B<textblock>
+
+B<interior_sequence>
+
+=over 4
+
+=item List Methods
+
+B<begin_list>
+
+=back
+
+B<end_list>
+
+B<add_item>
+
+=over 4
+
+=item Methods for headings
+
+B<head>
+
+=back
+
+=over 4
+
+=item Internal methods
+
+B<_output>
+
+=back
+
+B<_replace_special_chars>
+
+B<_replace_special_chars_late>
+
+B<_create_label>
+
+B<_create_index>
+
+B<_clean_latex_commands>
+
+B<_split_delimited>
+
+=over 4
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=item REVISION
+
+=back
+
+=head2 Pod::Man - Convert POD data to formatted *roff input
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+center, date, fixed, fixedbold, fixeditalic, fixedbolditalic, name, quotes,
+release, section, stderr, utf8
+
+=item DIAGNOSTICS
+
+roff font should be 1 or 2 chars, not "%s", Invalid quote specification
+"%s"
+
+=item BUGS
+
+=item CAVEATS
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=item SEE ALSO
+
+=back
+
+=head2 Pod::ParseLink - Parse an LE<lt>E<gt> formatting code in POD text
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::ParseUtils - helpers for POD parsing and conversion
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item Pod::List
+
+Pod::List-E<gt>new()
+
+=back
+
+$list-E<gt>file()
+
+$list-E<gt>start()
+
+$list-E<gt>indent()
+
+$list-E<gt>type()
+
+$list-E<gt>rx()
+
+$list-E<gt>item()
+
+$list-E<gt>parent()
+
+$list-E<gt>tag()
+
+=over 4
+
+=item Pod::Hyperlink
+
+Pod::Hyperlink-E<gt>new()
+
+=back
+
+$link-E<gt>parse($string)
+
+$link-E<gt>markup($string)
+
+$link-E<gt>text()
+
+$link-E<gt>warning()
+
+$link-E<gt>file(), $link-E<gt>line()
+
+$link-E<gt>page()
+
+$link-E<gt>node()
+
+$link-E<gt>alttext()
+
+$link-E<gt>type()
+
+$link-E<gt>link()
+
+=over 4
+
+=item Pod::Cache
+
+Pod::Cache-E<gt>new()
+
+=back
+
+$cache-E<gt>item()
+
+$cache-E<gt>find_page($name)
+
+=over 4
+
+=item Pod::Cache::Item
+
+Pod::Cache::Item-E<gt>new()
+
+=back
+
+$cacheitem-E<gt>page()
+
+$cacheitem-E<gt>description()
+
+$cacheitem-E<gt>path()
+
+$cacheitem-E<gt>file()
+
+$cacheitem-E<gt>nodes()
+
+$cacheitem-E<gt>find_node($name)
+
+$cacheitem-E<gt>idx()
+
+=over 4
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Pod::Parser - base class for creating POD filters and translators
+
+=over 4
+
+=item SYNOPSIS
+
+=item REQUIRES
+
+=item EXPORTS
+
+=item DESCRIPTION
+
+=item QUICK OVERVIEW
+
+=item PARSING OPTIONS
+
+B<-want_nonPODs> (default: unset), B<-process_cut_cmd> (default: unset),
+B<-warnings> (default: unset)
+
+=back
+
+=over 4
+
+=item RECOMMENDED SUBROUTINE/METHOD OVERRIDES
+
+=back
+
+=over 4
+
+=item B<command()>
+
+C<$cmd>, C<$text>, C<$line_num>, C<$pod_para>
+
+=back
+
+=over 4
+
+=item B<verbatim()>
+
+C<$text>, C<$line_num>, C<$pod_para>
+
+=back
+
+=over 4
+
+=item B<textblock()>
+
+C<$text>, C<$line_num>, C<$pod_para>
+
+=back
+
+=over 4
+
+=item B<interior_sequence()>
+
+=back
+
+=over 4
+
+=item OPTIONAL SUBROUTINE/METHOD OVERRIDES
+
+=back
+
+=over 4
+
+=item B<new()>
+
+=back
+
+=over 4
+
+=item B<initialize()>
+
+=back
+
+=over 4
+
+=item B<begin_pod()>
+
+=back
+
+=over 4
+
+=item B<begin_input()>
+
+=back
+
+=over 4
+
+=item B<end_input()>
+
+=back
+
+=over 4
+
+=item B<end_pod()>
+
+=back
+
+=over 4
+
+=item B<preprocess_line()>
+
+=back
+
+=over 4
+
+=item B<preprocess_paragraph()>
+
+=back
+
+=over 4
+
+=item METHODS FOR PARSING AND PROCESSING
+
+=back
+
+=over 4
+
+=item B<parse_text()>
+
+B<-expand_seq> =E<gt> I<code-ref>|I<method-name>, B<-expand_text> =E<gt>
+I<code-ref>|I<method-name>, B<-expand_ptree> =E<gt>
+I<code-ref>|I<method-name>
+
+=back
+
+=over 4
+
+=item B<interpolate()>
+
+=back
+
+=over 4
+
+=item B<parse_paragraph()>
+
+=back
+
+=over 4
+
+=item B<parse_from_filehandle()>
+
+=back
+
+=over 4
+
+=item B<parse_from_file()>
+
+=back
+
+=over 4
+
+=item ACCESSOR METHODS
+
+=back
+
+=over 4
+
+=item B<errorsub()>
+
+=back
+
+=over 4
+
+=item B<cutting()>
+
+=back
+
+=over 4
+
+=item B<parseopts()>
+
+=back
+
+=over 4
+
+=item B<output_file()>
+
+=back
+
+=over 4
+
+=item B<output_handle()>
+
+=back
+
+=over 4
+
+=item B<input_file()>
+
+=back
+
+=over 4
+
+=item B<input_handle()>
+
+=back
+
+=over 4
+
+=item B<input_streams()>
+
+=back
+
+=over 4
+
+=item B<top_stream()>
+
+=back
+
+=over 4
+
+=item PRIVATE METHODS AND DATA
+
+=back
+
+=over 4
+
+=item B<_push_input_stream()>
+
+=back
+
+=over 4
+
+=item B<_pop_input_stream()>
+
+=back
+
+=over 4
+
+=item TREE-BASED PARSING
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item LICENSE
+
+=back
+
+=head2 Pod::Perldoc - Look up Perl documentation in Pod format.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::BaseTo - Base for Pod::Perldoc formatters
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::GetOptsOO - Customized option parser for Pod::Perldoc
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToChecker - let Perldoc check Pod for errors
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToMan - let Perldoc render Pod as man pages
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEAT
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToNroff - let Perldoc convert Pod to nroff
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEAT
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToPod - let Perldoc render Pod as ... Pod!
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToRtf - let Perldoc render Pod as RTF
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToText - let Perldoc render Pod as plaintext
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEAT
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToTk - let Perldoc use Tk::Pod to render Pod
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Perldoc::ToXml - let Perldoc render Pod as XML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::PlainText - Convert POD data to formatted ASCII text
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+alt, indent, loose, sentence, width
+
+=item DIAGNOSTICS
+
+Bizarre space in item, Can't open %s for reading: %s, Unknown escape: %s,
+Unknown sequence: %s, Unmatched =back
+
+=item RESTRICTIONS
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Plainer - Perl extension for converting Pod to old-style Pod.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item METHODS
+
+escape_ltgt, simple_delimiters, textblock
+
+=item EXPORT
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::Select, podselect() - extract selected sections of POD from
+input
+
+=over 4
+
+=item SYNOPSIS
+
+=item REQUIRES
+
+=item EXPORTS
+
+=item DESCRIPTION
+
+=item SECTION SPECIFICATIONS
+
+=item RANGE SPECIFICATIONS
+
+=back
+
+=over 4
+
+=item OBJECT METHODS
+
+=back
+
+=over 4
+
+=item B<curr_headings()>
+
+=back
+
+=over 4
+
+=item B<select()>
+
+=back
+
+=over 4
+
+=item B<add_selection()>
+
+=back
+
+=over 4
+
+=item B<clear_selections()>
+
+=back
+
+=over 4
+
+=item B<match_section()>
+
+=back
+
+=over 4
+
+=item B<is_selected()>
+
+=back
+
+=over 4
+
+=item EXPORTED FUNCTIONS
+
+=back
+
+=over 4
+
+=item B<podselect()>
+
+B<-output>, B<-sections>, B<-ranges>
+
+=back
+
+=over 4
+
+=item PRIVATE METHODS AND DATA
+
+=back
+
+=over 4
+
+=item B<_compile_section_spec()>
+
+=back
+
+=over 4
+
+=item $self->{_SECTION_HEADINGS}
+
+=back
+
+=over 4
+
+=item $self->{_SELECTED_SECTIONS}
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Pod::Simple - framework for parsing Pod
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item MAIN METHODS
+
+C<< $parser = I<SomeClass>->new(); >>, C<< $parser->output_fh( *OUT ); >>,
+C<< $parser->output_string( \$somestring ); >>, C<< $parser->parse_file(
+I<$some_filename> ); >>, C<< $parser->parse_file( *INPUT_FH ); >>, C<<
+$parser->parse_string_document( I<$all_content> ); >>, C<<
+$parser->parse_lines( I<...@lines...>, undef ); >>, C<<
+$parser->content_seen >>, C<< I<SomeClass>->filter( I<$filename> ); >>, C<<
+I<SomeClass>->filter( I<*INPUT_FH> ); >>, C<< I<SomeClass>->filter(
+I<\$document_content> ); >>
+
+=item SECONDARY METHODS
+
+C<< $parser->no_whining( I<SOMEVALUE> ) >>, C<< $parser->no_errata_section(
+I<SOMEVALUE> ) >>, C<< $parser->complain_stderr( I<SOMEVALUE> ) >>, C<<
+$parser->source_filename >>, C<< $parser->doc_has_started >>, C<<
+$parser->source_dead >>, C<< $parser->strip_verbatim_indent( I<SOMEVALUE> )
+>>
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Checker -- check the Pod syntax of a document
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Debug -- put Pod::Simple into trace/debug mode
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEATS
+
+=item GUTS
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::DumpAsText -- dump Pod-parsing events as text
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::DumpAsXML -- turn Pod into XML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::HTML - convert Pod to HTML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CALLING FROM THE COMMAND LINE
+
+=item CALLING FROM PERL
+
+=item METHODS
+
+=item SUBCLASSING
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::HTMLBatch - convert several Pod files to several HTML
+files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item FROM THE COMMAND LINE
+
+=back
+
+=item MAIN METHODS
+
+$batchconv = Pod::Simple::HTMLBatch->new;, $batchconv->batch_convert(
+I<indirs>, I<outdir> );, $batchconv->batch_convert( undef , ...);,
+$batchconv->batch_convert( q{@INC}, ...);, $batchconv->batch_convert(
+\@dirs , ...);, $batchconv->batch_convert( "somedir" , ...);,
+$batchconv->batch_convert( 'somedir:someother:also' , ...);,
+$batchconv->batch_convert( ... , undef );, $batchconv->batch_convert( ... ,
+'somedir' );
+
+=over 4
+
+=item ACCESSOR METHODS
+
+$batchconv->verbose( I<nonnegative_integer> );, $batchconv->index(
+I<true-or-false> );, $batchconv->contents_file( I<filename> );,
+$batchconv->contents_page_start( I<HTML_string> );,
+$batchconv->contents_page_end( I<HTML_string> );, $batchconv->add_css( $url
+);, $batchconv->add_javascript( $url );, $batchconv->css_flurry(
+I<true-or-false> );, $batchconv->javascript_flurry( I<true-or-false> );,
+$batchconv->no_contents_links( I<true-or-false> );,
+$batchconv->html_render_class( I<classname> );, $batchconv->search_class(
+I<classname> );
+
+=back
+
+=item NOTES ON CUSTOMIZATION
+
+=item ASK ME!
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::LinkSection -- represent "section" attributes of L
+codes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Methody -- turn Pod::Simple events into method calls
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHOD CALLING
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::PullParser -- a pull-parser interface to parsing Pod
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+my $token = $parser->get_token, $parser->unget_token( $token ),
+$parser->unget_token( $token1, $token2, ... ), $parser->set_source(
+$filename ), $parser->set_source( $filehandle_object ),
+$parser->set_source( \$document_source ), $parser->set_source(
+\@document_lines ), $parser->parse_file(...),
+$parser->parse_string_document(...), $parser->filter(...),
+$parser->parse_from_file(...), my $title_string = $parser->get_title, my
+$title_string = $parser->get_short_title, $author_name =
+$parser->get_author, $description_name = $parser->get_description,
+$version_block = $parser->get_version
+
+=item NOTE
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::PullParserEndToken -- end-tokens from
+Pod::Simple::PullParser
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$token->tagname, $token->tagname(I<somestring>), $token->tag(...),
+$token->is_tag(I<somestring>) or $token->is_tagname(I<somestring>)
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::PullParserStartToken -- start-tokens from
+Pod::Simple::PullParser
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$token->tagname, $token->tagname(I<somestring>), $token->tag(...),
+$token->is_tag(I<somestring>) or $token->is_tagname(I<somestring>),
+$token->attr(I<attrname>), $token->attr(I<attrname>, I<newvalue>),
+$token->attr_hash
+
+=item SEE ALSO
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::PullParserTextToken -- text-tokens from
+Pod::Simple::PullParser
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$token->text, $token->text(I<somestring>), $token->text_r()
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::PullParserToken -- tokens from Pod::Simple::PullParser
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+$token->type, $token->is_start, $token->is_text, $token->is_end,
+$token->dump
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::RTF -- format Pod as RTF
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FORMAT CONTROL ATTRIBUTES
+
+$parser->head1_halfpoint_size( I<halfpoint_integer> );,
+$parser->head2_halfpoint_size( I<halfpoint_integer> );,
+$parser->head3_halfpoint_size( I<halfpoint_integer> );,
+$parser->head4_halfpoint_size( I<halfpoint_integer> );,
+$parser->codeblock_halfpoint_size( I<halfpoint_integer> );,
+$parser->header_halfpoint_size( I<halfpoint_integer> );,
+$parser->normal_halfpoint_size( I<halfpoint_integer> );,
+$parser->no_proofing_exemptions( I<true_or_false> );, $parser->doc_lang(
+I<microsoft_decimal_language_code> )
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Search - find POD documents in directory trees
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CONSTRUCTOR
+
+=item ACCESSORS
+
+$search->inc( I<true-or-false> );, $search->verbose( I<nonnegative-number>
+);, $search->limit_glob( I<some-glob-string> );, $search->callback(
+I<\&some_routine> );, $search->laborious( I<true-or-false> );,
+$search->shadows( I<true-or-false> );, $search->limit_re( I<some-regxp> );,
+$search->dir_prefix( I<some-string-value> );, $search->progress(
+I<some-progress-object> );, $name2path = $self->name2path;, $path2name =
+$self->path2name;
+
+=item MAIN SEARCH METHODS
+
+=over 4
+
+=item C<< $search->survey( @directories ) >>
+
+C<name2path>, C<path2name>
+
+=item C<< $search->simplify_name( $str ) >>
+
+=item C<< $search->find( $pod ) >>
+
+=item C<< $search->find( $pod, @search_dirs ) >>
+
+=item C<< $self->contains_pod( $file ) >>
+
+=back
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Subclassing -- write a formatter as a Pod::Simple
+subclass
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Events
+
+C<< $parser->_handle_element_start( I<element_name>, I<attr_hashref> ) >>,
+C<< $parser->_handle_element_end( I<element_name> ) >>, C<<
+$parser->_handle_text( I<text_string> ) >>, events with an element_name
+of Document, events with an element_name of Para, events with an
+element_name of B, C, F, or I, events with an element_name of S, events
+with an element_name of X, events with an element_name of L, events with an
+element_name of E or Z, events with an element_name of Verbatim, events
+with an element_name of head1 .. head4, events with an element_name of
+over-bullet, events with an element_name of over-number, events with an
+element_name of over-text, events with an element_name of over-block,
+events with an element_name of item-bullet, events with an element_name of
+item-number, events with an element_name of item-text, events with an
+element_name of for, events with an element_name of Data
+
+=item More Pod::Simple Methods
+
+C<< $parser->accept_targets( I<SOMEVALUE> ) >>, C<<
+$parser->accept_targets_as_text( I<SOMEVALUE> ) >>, C<<
+$parser->accept_codes( I<Codename>, I<Codename>... ) >>, C<<
+$parser->accept_directive_as_data( I<directive_name> ) >>, C<<
+$parser->accept_directive_as_verbatim( I<directive_name> ) >>, C<<
+$parser->accept_directive_as_processed( I<directive_name> ) >>, C<<
+$parser->nbsp_for_S( I<BOOLEAN> ); >>, C<< $parser->version_report() >>,
+C<< $parser->pod_para_count() >>, C<< $parser->line_count() >>, C<<
+$parser->nix_X_codes( I<SOMEVALUE> ) >>, C<< $parser->merge_text(
+I<SOMEVALUE> ) >>, C<< $parser->code_handler( I<CODE_REF> ) >>, C<<
+$parser->cut_handler( I<CODE_REF> ) >>, C<< $parser->whine(
+I<linenumber>, I<complaint string> ) >>, C<< $parser->scream(
+I<linenumber>, I<complaint string> ) >>, C<< $parser->source_dead(1) >>,
+C<< $parser->hide_line_numbers( I<SOMEVALUE> ) >>, C<< $parser->no_whining(
+I<SOMEVALUE> ) >>, C<< $parser->no_errata_section( I<SOMEVALUE> ) >>, C<<
+$parser->complain_stderr( I<SOMEVALUE> ) >>, C<< $parser->bare_output(
+I<SOMEVALUE> ) >>, C<< $parser->preserve_whitespace( I<SOMEVALUE> ) >>
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::Text -- format Pod as plaintext
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::TextContent -- get the text content of Pod
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::XHTML -- format Pod as validating XHTML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item perldoc_url_prefix
+
+=item perldoc_url_postfix
+
+=item man_url_prefix
+
+=item man_url_postfix
+
+=item title_prefix, title_postfix
+
+=item html_css
+
+=item html_javascript
+
+=item html_doctype
+
+=item html_header_tags
+
+=item html_h_level
+
+=item default_title
+
+=item force_title
+
+=item html_header, html_footer
+
+=item index
+
+=back
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=back
+
+=over 4
+
+=item handle_text
+
+=item accept_targets_as_html
+
+=back
+
+=over 4
+
+=item resolve_pod_page_link
+
+=back
+
+=over 4
+
+=item resolve_man_page_link
+
+=back
+
+=over 4
+
+=item idify
+
+=back
+
+=over 4
+
+=item batch_mode_page_object_init
+
+=back
+
+=over 4
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item ACKNOWLEDGEMENTS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Simple::XMLOutStream -- turn Pod into XML
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=item ABOUT EXTENDING POD
+
+=item ASK ME!
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::SimpleTree, Pod::Simple::SimpleTree -- parse Pod into a simple
+parse tree
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=item Tree Contents
+
+=item SEE ALSO
+
+=item SUPPORT
+
+=item COPYRIGHT AND DISCLAIMERS
+
+=item AUTHOR
+
+Allison Randal C<allison@perl.org>, Hans Dieter Pearcey C<hdp@cpan.org>,
+David E. Wheeler C<dwheeler@cpan.org>
+
+=back
+
+=head2 Pod::Text - Convert POD data to formatted ASCII text
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+alt, code, indent, loose, margin, quotes, sentence, stderr, utf8, width
+
+=item DIAGNOSTICS
+
+Bizarre space in item, Item called without tag, Can't open %s for reading:
+%s, Invalid quote specification "%s"
+
+=item BUGS
+
+=item CAVEATS
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::Text::Color - Convert POD data to formatted color ASCII text
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::Text::Overstrike, =for stopwords
+overstrike
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::Text::Termcap - Convert POD data to ASCII text with format
+escapes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Pod::Usage, pod2usage() - print a usage message from embedded pod
+documentation
+
+=over 4
+
+=item SYNOPSIS
+
+=item ARGUMENTS
+
+C<-message>, C<-msg>, C<-exitval>, C<-verbose>, C<-sections>, C<-output>,
+C<-input>, C<-pathlist>, C<-noperldoc>
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=over 4
+
+=item Recommended Use
+
+=back
+
+=item CAVEATS
+
+=item AUTHOR
+
+=item ACKNOWLEDGMENTS
+
+=item SEE ALSO
+
+=back
+
+=head2 SDBM_File - Tied access to sdbm files
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<O_RDONLY>, C<O_WRONLY>, C<O_RDWR>
+
+=item DIAGNOSTICS
+
+=over 4
+
+=item C<sdbm store returned -1, errno 22, key "..." at ...>
+
+=back
+
+=item BUGS AND WARNINGS
+
+=back
+
+=head2 Safe - Compile and execute code in restricted compartments
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+a new namespace, an operator mask
+
+=item WARNING
+
+=item METHODS
+
+=over 4
+
+=item permit (OP, ...)
+
+=item permit_only (OP, ...)
+
+=item deny (OP, ...)
+
+=item deny_only (OP, ...)
+
+=item trap (OP, ...)
+
+=item untrap (OP, ...)
+
+=item share (NAME, ...)
+
+=item share_from (PACKAGE, ARRAYREF)
+
+=item varglob (VARNAME)
+
+=item reval (STRING, STRICT)
+
+=item rdo (FILENAME)
+
+=item root (NAMESPACE)
+
+=item mask (MASK)
+
+=item wrap_code_ref (CODEREF)
+
+=item wrap_code_refs_within (...)
+
+=back
+
+=item RISKS
+
+Memory, CPU, Snooping, Signals, State Changes
+
+=item AUTHOR
+
+=back
+
+=head2 Scalar::Util - A selection of general-utility scalar subroutines
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+blessed EXPR, dualvar NUM, STRING, isvstring EXPR, isweak EXPR,
+looks_like_number EXPR, openhandle FH, refaddr EXPR, reftype EXPR,
+set_prototype CODEREF, PROTOTYPE, tainted EXPR, weaken REF
+
+=item DIAGNOSTICS
+
+Weak references are not implemented in the version of perl, Vstrings are
+not implemented in the version of perl, C<NAME> is only available with the
+XS version of Scalar::Util
+
+=item KNOWN BUGS
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 Search::Dict, look - search for key in dictionary file
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 SelectSaver - save and restore selected file handle
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 SelfLoader - load functions only on demand
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item The __DATA__ token
+
+=item SelfLoader autoloading
+
+=item Autoloading and package lexicals
+
+=item SelfLoader and AutoLoader
+
+=item __DATA__, __END__, and the FOOBAR::DATA filehandle.
+
+=item Classes and inherited methods.
+
+=back
+
+=item Multiple packages and fully qualified subroutine names
+
+=item AUTHOR
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+B<_make_cmd>
+
+=head2 Shell - run shell commands transparently within perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Caveats
+
+=item Escaping Magic Characters
+
+=item Configuration
+
+=back
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 Socket, sockaddr_in, sockaddr_un, inet_aton, inet_ntoa, inet_pton,
+inet_ntop - load the C socket.h defines and structure manipulators
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+inet_aton HOSTNAME, inet_ntoa IP_ADDRESS, INADDR_ANY, INADDR_BROADCAST,
+INADDR_LOOPBACK, INADDR_NONE, sockaddr_family SOCKADDR, sockaddr_in PORT,
+ADDRESS, sockaddr_in SOCKADDR_IN, pack_sockaddr_in PORT, IP_ADDRESS,
+unpack_sockaddr_in SOCKADDR_IN, sockaddr_un PATHNAME, sockaddr_un
+SOCKADDR_UN, pack_sockaddr_un PATH, unpack_sockaddr_un SOCKADDR_UN,
+inet_pton ADDRESS_FAMILY, HOSTNAME, inet_ntop ADDRESS_FAMILY, IP_ADDRESS
+
+=back
+
+=head2 Storable - persistence for Perl data structures
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item MEMORY STORE
+
+=item ADVISORY LOCKING
+
+=item SPEED
+
+=item CANONICAL REPRESENTATION
+
+=item CODE REFERENCES
+
+=item FORWARD COMPATIBILITY
+
+utf8 data, restricted hashes, files from future versions of Storable
+
+=item ERROR REPORTING
+
+=item WIZARDS ONLY
+
+=over 4
+
+=item Hooks
+
+C<STORABLE_freeze> I<obj>, I<cloning>, C<STORABLE_thaw> I<obj>, I<cloning>,
+I<serialized>, .., C<STORABLE_attach> I<class>, I<cloning>, I<serialized>
+
+=item Predicates
+
+C<Storable::last_op_in_netorder>, C<Storable::is_storing>,
+C<Storable::is_retrieving>
+
+=item Recursion
+
+=item Deep Cloning
+
+=back
+
+=item Storable magic
+
+$info = Storable::file_magic( $filename ), C<version>, C<version_nv>,
+C<major>, C<minor>, C<hdrsize>, C<netorder>, C<byteorder>, C<intsize>,
+C<longsize>, C<ptrsize>, C<nvsize>, C<file>, $info = Storable::read_magic(
+$buffer ), $info = Storable::read_magic( $buffer, $must_be_file )
+
+=item EXAMPLES
+
+=item WARNING
+
+=item BUGS
+
+=over 4
+
+=item 64 bit data in perl 5.6.0 and 5.6.1
+
+=back
+
+=item CREDITS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Switch - A switch statement for Perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item BACKGROUND
+
+=item DESCRIPTION
+
+=over 4
+
+=item Allowing fall-through
+
+=item Automating fall-through
+
+=item Alternative syntax
+
+=item Higher-order Operations
+
+=back
+
+=item DEPENDENCIES
+
+=item AUTHOR
+
+=item BUGS
+
+=item LIMITATIONS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Symbol - manipulate Perl symbols and their names
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item BUGS
+
+=back
+
+=head2 Sys-Hostname, Sys::Hostname - Try every conceivable way to get
+hostname
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 Sys::Hostname - Try every conceivable way to get hostname
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 TAP::Base - Base class that provides common functionality to
+L<TAP::Parser>
+and L<TAP::Harness>
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAP::Formatter::Base, TAP::Formatter::Console - Harness output
+delegate for default console output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+C<verbosity>, C<verbose>, C<timer>, C<failures>, C<comments>, C<quiet>,
+C<really_quiet>, C<silent>, C<errors>, C<directives>, C<stdout>, C<color>,
+C<jobs>, C<show_count>
+
+=back
+
+=back
+
+=head2 TAP::Formatter::Color - Run Perl test scripts with color
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAP::Formatter::Console - Harness output delegate for default
+console output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=over 4
+
+=item C<< open_test >>
+
+=back
+
+=back
+
+=head2 TAP::Formatter::Console::ParallelSession - Harness output delegate
+for parallel console output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAP::Formatter::Console::Session - Harness output delegate for
+default console output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item C<< clear_for_close >>
+
+=item C<< close_test >>
+
+=item C<< header >>
+
+=item C<< result >>
+
+=back
+
+=head2 TAP::Formatter::File - Harness output delegate for file output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=over 4
+
+=item C<< open_test >>
+
+=back
+
+=back
+
+=head2 TAP::Formatter::File::Session - Harness output delegate for file
+output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item result
+
+=back
+
+=back
+
+=over 4
+
+=item close_test
+
+=back
+
+=head2 TAP::Formatter::Session - Abstract base class for harness output
+delegate
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+C<formatter>, C<parser>, C<name>, C<show_count>
+
+=back
+
+=back
+
+=head2 TAP::Harness - Run test scripts with statistics
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item SYNOPSIS
+
+=back
+
+=over 4
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+C<verbosity>, C<timer>, C<failures>, C<comments>, C<show_count>,
+C<normalize>, C<lib>, C<switches>, C<test_args>, C<color>, C<exec>,
+C<merge>, C<aggregator_class>, C<formatter_class>, C<multiplexer_class>,
+C<parser_class>, C<scheduler_class>, C<formatter>, C<errors>,
+C<directives>, C<ignore_exit>, C<jobs>, C<rules>, C<stdout>
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+the file name of a test script to run, a reference to a [ file name,
+display name ] array
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Methods
+
+C<start>, C<tests>
+
+=back
+
+=back
+
+=over 4
+
+=item REPLACING
+
+=item SEE ALSO
+
+=back
+
+=head2 TAP::Object - Base class that provides common functionality to all
+C<TAP::*> modules
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser, TAP::Parser - Parse L<TAP|Test::Harness::TAP> output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+C<source>, C<tap>, C<exec>, C<callback>, C<switches>, C<test_args>,
+C<spool>, C<merge>, C<source_class>, C<perl_source_class>,
+C<grammar_class>, C<iterator_factory_class>, C<result_factory_class>
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item INDIVIDUAL RESULTS
+
+=over 4
+
+=item Result types
+
+Version, Plan, Pragma, Test, Comment, Bailout, Unknown
+
+=item Common type methods
+
+=item C<plan> methods
+
+=item C<pragma> methods
+
+=item C<bailout> methods
+
+=item C<unknown> methods
+
+=item C<test> methods
+
+=back
+
+=item TOTAL RESULTS
+
+=over 4
+
+=item Individual Results
+
+=back
+
+=back
+
+=over 4
+
+=item Pragmas
+
+=back
+
+=over 4
+
+=item Summary Results
+
+=back
+
+=over 4
+
+=item C<ignore_exit>
+
+=back
+
+Misplaced plan, No plan, More than one plan, Test numbers out of sequence
+
+=over 4
+
+=item CALLBACKS
+
+C<test>, C<version>, C<plan>, C<comment>, C<bailout>, C<yaml>, C<unknown>,
+C<ELSE>, C<ALL>, C<EOF>
+
+=item TAP GRAMMAR
+
+=item BACKWARDS COMPATABILITY
+
+=over 4
+
+=item Differences
+
+TODO plans, 'Missing' tests
+
+=back
+
+=item SUBCLASSING
+
+=over 4
+
+=item Parser Components
+
+option 1, option 2
+
+=back
+
+=item ACKNOWLEDGEMENTS
+
+Michael Schwern, Andy Lester, chromatic, GEOFFR, Shlomi Fish, Torsten
+Schoenfeld, Jerry Gay, Aristotle, Adam Kennedy, Yves Orton, Adrian Howard,
+Sean & Lil, Andreas J. Koenig, Florian Ragwitz, Corion, Mark Stosberg, Matt
+Kraai, David Wheeler, Alex Vandiver
+
+=item AUTHORS
+
+=item BUGS
+
+=item COPYRIGHT & LICENSE
+
+=back
+
+=head2 TAParser::Aggregator, TAP::Parser::Aggregator - Aggregate
+TAP::Parser results
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item Summary methods
+
+failed, parse_errors, passed, planned, skipped, todo, todo_passed, wait,
+exit
+
+=back
+
+Failed tests, Parse errors, Bad exit or wait status
+
+=over 4
+
+=item See Also
+
+=back
+
+=head2 TAParser::Grammar, TAP::Parser::Grammar - A grammar for the Test
+Anything Protocol.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item TAP GRAMMAR
+
+=item SUBCLASSING
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Iterator, TAP::Parser::Iterator - Internal base class for
+TAP::Parser Iterators
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+=back
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Iterator::Array, TAP::Parser::Iterator::Array - Internal
+TAP::Parser array Iterator
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+=back
+
+=back
+
+=over 4
+
+=item ATTRIBUTION
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Iterator::Process, TAP::Parser::Iterator::Process -
+Internal TAP::Parser Iterator
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+=back
+
+=back
+
+=over 4
+
+=item ATTRIBUTION
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Iterator::Stream, TAP::Parser::Iterator::Stream - Internal
+TAP::Parser Iterator
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item ATTRIBUTION
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::IteratorFactory, TAP::Parser::IteratorFactory - Internal
+TAP::Parser Iterator
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item ATTRIBUTION
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Multiplexer, TAP::Parser::Multiplexer - Multiplex multiple
+TAP::Parsers
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item See Also
+
+=back
+
+=head2 TAParser::Result, TAP::Parser::Result - Base class for TAP::Parser
+output objects
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=over 4
+
+=item DESCRIPTION
+
+=item METHODS
+
+=back
+
+=back
+
+=over 4
+
+=item Boolean methods
+
+C<is_plan>, C<is_pragma>, C<is_test>, C<is_comment>, C<is_bailout>,
+C<is_version>, C<is_unknown>, C<is_yaml>
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Result::Bailout, TAP::Parser::Result::Bailout - Bailout
+result token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::Result::Comment, TAP::Parser::Result::Comment - Comment
+result token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::Result::Plan, TAP::Parser::Result::Plan - Plan result
+token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>, C<raw>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::Result::Pragma, TAP::Parser::Result::Pragma - TAP pragma
+token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>, C<raw>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::Result::Test, TAP::Parser::Result::Test - Test result
+token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=back
+
+=head2 TAParser::Result::Unknown, TAP::Parser::Result::Unknown - Unknown
+result token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>, C<raw>
+
+=back
+
+=head2 TAParser::Result::Version, TAP::Parser::Result::Version - TAP syntax
+version token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>, C<raw>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::Result::YAML, TAP::Parser::Result::YAML - YAML result
+token.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item OVERRIDDEN METHODS
+
+C<as_string>, C<raw>
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=head2 TAParser::ResultFactory, TAP::Parser::ResultFactory - Factory for
+creating TAP::Parser output objects
+
+=over 4
+
+=item SYNOPSIS
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item DESCRIPTION
+
+=item METHODS
+
+=item Class Methods
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Scheduler, TAP::Parser::Scheduler - Schedule tests during
+parallel testing
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAParser::Scheduler::Job, TAP::Parser::Scheduler::Job - A single
+testing job.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAParser::Scheduler::Spinner, TAP::Parser::Scheduler::Spinner - A
+no-op job.
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=head2 TAParser::Source, TAP::Parser::Source - Stream output from some
+source
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=back
+
+=back
+
+=over 4
+
+=item Instance Methods
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Source::Perl, TAP::Parser::Source::Perl - Stream Perl
+output
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+=back
+
+=back
+
+=over 4
+
+=item SUBCLASSING
+
+=over 4
+
+=item Example
+
+=back
+
+=item SEE ALSO
+
+=back
+
+=head2 TAParser::Utils, TAP::Parser::Utils - Internal TAP::Parser utilities
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item INTERFACE
+
+=back
+
+=back
+
+=head2 TAParser::YAMLish::Reader, TAP::Parser::YAMLish::Reader - Read
+YAMLish data from iterator
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 TAParser::YAMLish::Writer, TAP::Parser::YAMLish::Writer - Write
+YAMLish data
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=over 4
+
+=item Class Methods
+
+=item Instance Methods
+
+a reference to a scalar to append YAML to, the handle of an open file, a
+reference to an array into which YAML will be pushed, a code reference
+
+=back
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=item COPYRIGHT
+
+=back
+
+=head2 Term::ANSIColor - Color screen output using ANSI escape sequences
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Function Interface
+
+=item Constant Interface
+
+=item The Color Stack
+
+=back
+
+=item DIAGNOSTICS
+
+Bad escape sequence %s, Bareword "%s" not allowed while "strict subs" in
+use, Invalid attribute name %s, Name "%s" used only once: possible typo, No
+comma allowed after filehandle, No name for escape sequence %s
+
+=item ENVIRONMENT
+
+ANSI_COLORS_DISABLED
+
+=item RESTRICTIONS
+
+=item NOTES
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Term::Cap - Perl termcap interface
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item METHODS
+
+=back
+
+=back
+
+B<Tgetent>, OSPEED, TERM
+
+B<Tpad>, B<$string>, B<$cnt>, B<$FH>
+
+B<Tputs>, B<$cap>, B<$cnt>, B<$FH>
+
+B<Tgoto>, B<$cap>, B<$col>, B<$row>, B<$FH>
+
+B<Trequire>
+
+=over 4
+
+=item EXAMPLES
+
+=item COPYRIGHT AND LICENSE
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Term::Complete - Perl word completion module
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+E<lt>tabE<gt>, ^D, ^U, E<lt>delE<gt>, E<lt>bsE<gt>
+
+=item DIAGNOSTICS
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 Term::ReadLine - Perl interface to various C<readline> packages.
+If no real package is found, substitutes stubs instead of basic functions.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Minimal set of supported functions
+
+C<ReadLine>, C<new>, C<readline>, C<addhistory>, C<IN>, C<OUT>, C<MinLine>,
+C<findConsole>, Attribs, C<Features>
+
+=item Additional supported functions
+
+C<tkRunning>, C<ornaments>, C<newTTY>
+
+=item EXPORTS
+
+=item ENVIRONMENT
+
+=item CAVEATS
+
+=back
+
+=head2 Term::UI - Term::ReadLine UI made easy
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item HOW IT WORKS
+
+=item METHODS
+
+=over 4
+
+=item $reply = $term->get_reply( prompt => 'question?', [choices => \@list,
+default => $list[0], multi => BOOL, print_me => "extra text to print &
+record", allow => $ref] );
+
+=back
+
+=back
+
+=over 4
+
+=item $bool = $term->ask_yn( prompt => "your question", [default =>
+(y|1,n|0), print_me => "extra text to print & record"] )
+
+=back
+
+=over 4
+
+=item ($opts, $munged) = $term->parse_options( STRING );
+
+=back
+
+=over 4
+
+=item $str = $term->history_as_string
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+=over 4
+
+=item $Term::UI::VERBOSE
+
+=item $Term::UI::AUTOREPLY
+
+=item $Term::UI::INVALID
+
+=item $Term::UI::History::HISTORY_FH
+
+=back
+
+=item EXAMPLES
+
+=over 4
+
+=item Basic get_reply sample
+
+=item get_reply with choices
+
+=item get_reply with choices and default
+
+=item get_reply using print_me & multi
+
+=item get_reply & allow
+
+=item an elaborate ask_yn sample
+
+=back
+
+=item See Also
+
+=item BUG REPORTS
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Term::UI::History
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item history("message string" [,VERBOSE])
+
+=back
+
+=back
+
+=over 4
+
+=item GLOBAL VARIABLES
+
+$HISTORY_FH
+
+=item See Also
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=back
+
+=head2 Test - provides a simple framework for writing test scripts
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item QUICK START GUIDE
+
+=over 4
+
+=item Functions
+
+C<plan(...)>, C<tests =E<gt> I<number>>, C<todo =E<gt> [I<1,5,14>]>,
+C<onfail =E<gt> sub { ... }>, C<onfail =E<gt> \&some_sub>
+
+=back
+
+=back
+
+B<_to_value>
+
+C<ok(...)>
+
+C<skip(I<skip_if_true>, I<args...>)>
+
+=over 4
+
+=item TEST TYPES
+
+NORMAL TESTS, SKIPPED TESTS, TODO TESTS
+
+=item ONFAIL
+
+=item BUGS and CAVEATS
+
+=item ENVIRONMENT
+
+=item NOTE
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=back
+
+=head2 Test::Builder - Backend for building test libraries
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Construction
+
+B<new>
+
+=back
+
+=back
+
+B<create>
+
+B<child>
+
+B<subtest>
+
+B<finalize>
+
+B<parent>
+
+B<name>
+
+B<reset>
+
+=over 4
+
+=item Setting up tests
+
+B<plan>
+
+=back
+
+B<expected_tests>
+
+B<no_plan>
+
+B<_output_plan>
+
+B<done_testing>
+
+B<has_plan>
+
+B<skip_all>
+
+B<exported_to>
+
+=over 4
+
+=item Running tests
+
+B<ok>
+
+=back
+
+B<is_eq>, B<is_num>
+
+B<isnt_eq>, B<isnt_num>
+
+B<like>, B<unlike>
+
+B<cmp_ok>
+
+=over 4
+
+=item Other Testing Methods
+
+B<BAIL_OUT>
+
+=back
+
+B<skip>
+
+B<todo_skip>
+
+B<skip_rest>
+
+=over 4
+
+=item Test building utility methods
+
+B<maybe_regex>
+
+=back
+
+B<_try>
+
+B<is_fh>
+
+=over 4
+
+=item Test style
+
+B<level>
+
+=back
+
+B<use_numbers>
+
+B<no_diag>, B<no_ending>, B<no_header>
+
+=over 4
+
+=item Output
+
+B<diag>
+
+=back
+
+B<note>
+
+B<explain>
+
+B<_print>
+
+B<output>, B<failure_output>, B<todo_output>
+
+reset_outputs
+
+carp, croak
+
+=over 4
+
+=item Test Status and Info
+
+B<current_test>
+
+=back
+
+B<is_passing>
+
+B<summary>
+
+B<details>
+
+B<todo>
+
+B<find_TODO>
+
+B<in_todo>
+
+B<todo_start>
+
+C<todo_end>
+
+B<caller>
+
+B<_sanity_check>
+
+B<_whoa>
+
+B<_my_exit>
+
+=over 4
+
+=item EXIT CODES
+
+=item THREADS
+
+=item MEMORY
+
+=item EXAMPLES
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Test::Builder::Module - Base class for test modules
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Importing
+
+=back
+
+=back
+
+=over 4
+
+=item Builder
+
+=back
+
+=head2 Test::Builder::Tester - test testsuites that have been built with
+Test::Builder
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item Functions
+
+test_out, test_err
+
+=back
+
+test_fail
+
+test_diag
+
+test_test, title (synonym 'name', 'label'), skip_out, skip_err
+
+line_num
+
+color
+
+=over 4
+
+=item BUGS
+
+=item AUTHOR
+
+=item NOTES
+
+=item SEE ALSO
+
+=back
+
+=head2 Test::Builder::Tester::Color - turn on colour in
+Test::Builder::Tester
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item AUTHOR
+
+=item BUGS
+
+=item SEE ALSO
+
+=back
+
+=head2 Test::Harness - Run Perl standard test scripts with statistics
+
+=over 4
+
+=item VERSION
+
+=back
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item runtests( @test_files )
+
+=back
+
+=back
+
+=over 4
+
+=item execute_tests( tests => \@test_files, out => \*FH )
+
+=back
+
+=over 4
+
+=item EXPORT
+
+=item ENVIRONMENT VARIABLES THAT TAP::HARNESS::COMPATIBLE SETS
+
+C<HARNESS_ACTIVE>, C<HARNESS_VERSION>
+
+=item ENVIRONMENT VARIABLES THAT AFFECT TEST::HARNESS
+
+C<HARNESS_TIMER>, C<HARNESS_VERBOSE>, C<HARNESS_OPTIONS>, C<< j<n> >>, C<<
+f >>
+
+=item Taint Mode
+
+=item SEE ALSO
+
+=item BUGS
+
+=item AUTHORS
+
+=item LICENCE AND COPYRIGHT
+
+=back
+
+=head2 Test::More - yet another framework for writing test scripts
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item I love it when a plan comes together
+
+=back
+
+=back
+
+B<done_testing>
+
+=over 4
+
+=item Test names
+
+=item I'm ok, you're not ok.
+
+B<ok>
+
+=back
+
+B<is>, B<isnt>
+
+B<like>
+
+B<unlike>
+
+B<cmp_ok>
+
+B<can_ok>
+
+B<isa_ok>
+
+B<new_ok>
+
+B<subtest>
+
+B<pass>, B<fail>
+
+=over 4
+
+=item Module tests
+
+B<use_ok>
+
+=back
+
+B<require_ok>
+
+=over 4
+
+=item Complex data structures
+
+B<is_deeply>
+
+=back
+
+=over 4
+
+=item Diagnostics
+
+B<diag>, B<note>
+
+=back
+
+B<explain>
+
+=over 4
+
+=item Conditional tests
+
+B<SKIP: BLOCK>
+
+=back
+
+B<TODO: BLOCK>, B<todo_skip>
+
+When do I use SKIP vs. TODO?
+
+=over 4
+
+=item Test control
+
+B<BAIL_OUT>
+
+=back
+
+=over 4
+
+=item Discouraged comparison functions
+
+B<eq_array>
+
+=back
+
+B<eq_hash>
+
+B<eq_set>
+
+=over 4
+
+=item Extending and Embedding Test::More
+
+B<builder>
+
+=back
+
+=over 4
+
+=item EXIT CODES
+
+=item CAVEATS and NOTES
+
+Backwards compatibility, utf8 / "Wide character in print", Overloaded
+objects, Threads
+
+=item HISTORY
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item BUGS
+
+=item SOURCE
+
+=item COPYRIGHT
+
+=back
+
+=head2 Test::Simple - Basic utilities for writing tests.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+B<ok>
+
+=back
+
+=over 4
+
+=item EXAMPLE
+
+=item CAVEATS
+
+=item NOTES
+
+=item HISTORY
+
+=item SEE ALSO
+
+L<Test::More>
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Test::Tutorial - A tutorial about writing really basic tests
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Nuts and bolts of testing.
+
+=item Where to start?
+
+=item Names
+
+=item Test the manual
+
+=item Sometimes the tests are wrong
+
+=item Testing lots of values
+
+=item Informative names
+
+=item Skipping tests
+
+=item Todo tests
+
+=item Testing with taint mode.
+
+=back
+
+=item FOOTNOTES
+
+=item AUTHORS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Text::Abbrev, abbrev - create an abbreviation table from a list
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLE
+
+=back
+
+=head2 Text::Balanced - Extract delimited text sequences from strings.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item General behaviour in list contexts
+
+[0], [1], [2]
+
+=item General behaviour in scalar and void contexts
+
+=item A note about prefixes
+
+=item C<extract_delimited>
+
+=item C<extract_bracketed>
+
+=item C<extract_variable>
+
+[0], [1], [2]
+
+=item C<extract_tagged>
+
+C<reject =E<gt> $listref>, C<ignore =E<gt> $listref>, C<fail =E<gt> $str>,
+[0], [1], [2], [3], [4], [5]
+
+=item C<gen_extract_tagged>
+
+=item C<extract_quotelike>
+
+[0], [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]
+
+=item C<extract_quotelike> and "here documents"
+
+[0], [1], [2], [3], [4], [5], [6], [7..10]
+
+=item C<extract_codeblock>
+
+=item C<extract_multiple>
+
+=item C<gen_delimited_pat>
+
+=item C<delimited_pat>
+
+=back
+
+=item DIAGNOSTICS
+
+ C<Did not find a suitable bracket: "%s">, C<Did not find prefix: /%s/>,
+C<Did not find opening bracket after prefix: "%s">, C<No quotelike
+operator found after prefix: "%s">, C<Unmatched closing bracket: "%c">,
+C<Unmatched opening bracket(s): "%s">, C<Unmatched embedded quote (%s)>,
+C<Did not find closing delimiter to match '%s'>, C<Mismatched closing
+bracket: expected "%c" but found "%s">, C<No block delimiter found after
+quotelike "%s">, C<Did not find leading dereferencer>, C<Bad identifier
+after dereferencer>, C<Did not find expected opening bracket at %s>,
+C<Improperly nested codeblock at %s>, C<Missing second block for quotelike
+"%s">, C<No match found for opening bracket>, C<Did not find opening tag:
+/%s/>, C<Unable to construct closing tag to match: /%s/>, C<Found invalid
+nested tag: %s>, C<Found unbalanced nested tag: %s>, C<Did not find closing
+tag>
+
+=item AUTHOR
+
+=item BUGS AND IRRITATIONS
+
+=item COPYRIGHT
+
+=back
+
+=head2 Text::ParseWords - parse text into an array of tokens or array of
+arrays
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item AUTHORS
+
+=back
+
+=head2 Text::Soundex - Implementation of the soundex algorithm.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLES
+
+=item LIMITATIONS
+
+=item MAINTAINER
+
+=item HISTORY
+
+=back
+
+=head2 Text::Tabs -- expand and unexpand tabs per the unix expand(1) and
+unexpand(1)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLE
+
+=item LICENSE
+
+=back
+
+=head2 Text::Wrap - line wrapping to form simple paragraphs
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item OVERRIDES
+
+=item EXAMPLES
+
+=item SEE ALSO
+
+=item LICENSE
+
+=back
+
+=head2 Thread - Manipulate threads in Perl (for old code only)
+
+=over 4
+
+=item DEPRECATED
+
+=item HISTORY
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+$thread = Thread->new(\&start_sub), $thread = Thread->new(\&start_sub,
+LIST), lock VARIABLE, async BLOCK;, Thread->self, Thread->list, cond_wait
+VARIABLE, cond_signal VARIABLE, cond_broadcast VARIABLE, yield
+
+=item METHODS
+
+join, detach, equal, tid, done
+
+=item DEFUNCT
+
+lock(\&sub), eval, flags
+
+=item SEE ALSO
+
+=back
+
+=head2 Thread::Queue - Thread-safe queues
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+Ordinary scalars, Array refs, Hash refs, Scalar refs, Objects based on the
+above
+
+=item QUEUE CREATION
+
+->new(), ->new(LIST)
+
+=item BASIC METHODS
+
+->enqueue(LIST), ->dequeue(), ->dequeue(COUNT), ->dequeue_nb(),
+->dequeue_nb(COUNT), ->pending()
+
+=item ADVANCED METHODS
+
+->peek(), ->peek(INDEX), ->insert(INDEX, LIST), ->extract(),
+->extract(INDEX), ->extract(INDEX, COUNT)
+
+=item NOTES
+
+=item LIMITATIONS
+
+=item SEE ALSO
+
+=item MAINTAINER
+
+=item LICENSE
+
+=back
+
+=head2 Thread::Semaphore - Thread-safe semaphores
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+->new(), ->new(NUMBER), ->down(), ->down(NUMBER), ->up(), ->up(NUMBER)
+
+=item NOTES
+
+=item SEE ALSO
+
+=item MAINTAINER
+
+=item LICENSE
+
+=back
+
+=head2 Tie-Memoize::lib::Tie::Memoize, Tie::Memoize - add data to hash when
+needed
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Inheriting from B<Tie::Memoize>
+
+=item EXAMPLE
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 Tie::Array - base class for tied arrays
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+TIEARRAY classname, LIST, STORE this, index, value, FETCH this, index,
+FETCHSIZE this, STORESIZE this, count, EXTEND this, count, EXISTS this,
+key, DELETE this, key, CLEAR this, DESTROY this, PUSH this, LIST, POP this,
+SHIFT this, UNSHIFT this, LIST, SPLICE this, offset, length, LIST
+
+=item CAVEATS
+
+=item AUTHOR
+
+=back
+
+=head2 Tie::File - Access the lines of a disk file via a Perl array
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item C<recsep>
+
+=item C<autochomp>
+
+=item C<mode>
+
+=item C<memory>
+
+=item C<dw_size>
+
+=item Option Format
+
+=back
+
+=item Public Methods
+
+=over 4
+
+=item C<flock>
+
+=item C<autochomp>
+
+=item C<defer>, C<flush>, C<discard>, and C<autodefer>
+
+=item C<offset>
+
+=back
+
+=item Tying to an already-opened filehandle
+
+=item Deferred Writing
+
+=over 4
+
+=item Autodeferring
+
+=back
+
+=item CONCURRENT ACCESS TO FILES
+
+=item CAVEATS
+
+=item SUBCLASSING
+
+=item WHAT ABOUT C<DB_File>?
+
+=item AUTHOR
+
+=item LICENSE
+
+=item WARRANTY
+
+=item THANKS
+
+=item TODO
+
+=back
+
+=head2 Tie::Handle - base class definitions for tied handles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+TIEHANDLE classname, LIST, WRITE this, scalar, length, offset, PRINT this,
+LIST, PRINTF this, format, LIST, READ this, scalar, length, offset,
+READLINE this, GETC this, CLOSE this, OPEN this, filename, BINMODE this,
+EOF this, TELL this, SEEK this, offset, whence, DESTROY this
+
+=item MORE INFORMATION
+
+=item COMPATIBILITY
+
+=back
+
+=head2 Tie::Hash, Tie::StdHash, Tie::ExtraHash - base class definitions for
+tied hashes
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+TIEHASH classname, LIST, STORE this, key, value, FETCH this, key, FIRSTKEY
+this, NEXTKEY this, lastkey, EXISTS this, key, DELETE this, key, CLEAR
+this, SCALAR this
+
+=item Inheriting from B<Tie::StdHash>
+
+=item Inheriting from B<Tie::ExtraHash>
+
+=item C<SCALAR>, C<UNTIE> and C<DESTROY>
+
+=item MORE INFORMATION
+
+=back
+
+=head2 Tie::Hash::NamedCapture - Named regexp capture buffers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item SEE ALSO
+
+=back
+
+=head2 Tie::Memoize - add data to hash when needed
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item Inheriting from B<Tie::Memoize>
+
+=item EXAMPLE
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 Tie::RefHash - use references as hash keys
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item EXAMPLE
+
+=item THREAD SUPPORT
+
+=item STORABLE SUPPORT
+
+=item RELIC SUPPORT
+
+=item MAINTAINER
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Tie::Scalar, Tie::StdScalar - base class definitions for tied
+scalars
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+TIESCALAR classname, LIST, FETCH this, STORE this, value, DESTROY this
+
+=over 4
+
+=item Tie::Scalar vs Tie::StdScalar
+
+=back
+
+=item MORE INFORMATION
+
+=back
+
+=head2 Tie::StdHandle - base class definitions for tied handles
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=head2 Tie::SubstrHash - Fixed-table-size, fixed-key-length hashing
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item CAVEATS
+
+=back
+
+=head2 Time-Localib::Time::Local, Time::Local - efficiently compute time
+from local and GMT time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item C<timelocal()> and C<timegm()>
+
+=item C<timelocal_nocheck()> and C<timegm_nocheck()>
+
+=item Year Value Interpretation
+
+=item Ambiguous Local Times (DST)
+
+=item Non-Existent Local Times (DST)
+
+=back
+
+=item IMPLEMENTATION
+
+=item BUGS
+
+=item SUPPORT
+
+=item COPYRIGHT
+
+=item AUTHOR
+
+=back
+
+=head2 Time::HiRes - High resolution alarm, sleep, gettimeofday, interval
+timers
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+gettimeofday (), usleep ( $useconds ), nanosleep ( $nanoseconds ), ualarm (
+$useconds [, $interval_useconds ] ), tv_interval, time (), sleep (
+$floating_seconds ), alarm ( $floating_seconds [,
+$interval_floating_seconds ] ), setitimer ( $which, $floating_seconds [,
+$interval_floating_seconds ] ), getitimer ( $which ), clock_gettime (
+$which ), clock_getres ( $which ), clock_nanosleep ( $which, $nanoseconds,
+$flags = 0), clock(), stat, stat FH, stat EXPR
+
+=item EXAMPLES
+
+=item C API
+
+=item DIAGNOSTICS
+
+=over 4
+
+=item useconds or interval more than ...
+
+=item negative time not invented yet
+
+=item internal error: useconds < 0 (unsigned ... signed ...)
+
+=item useconds or uinterval equal to or more than 1000000
+
+=item unimplemented in this platform
+
+=back
+
+=item CAVEATS
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 Time::Local - efficiently compute time from local and GMT time
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item FUNCTIONS
+
+=over 4
+
+=item C<timelocal()> and C<timegm()>
+
+=item C<timelocal_nocheck()> and C<timegm_nocheck()>
+
+=item Year Value Interpretation
+
+=item Ambiguous Local Times (DST)
+
+=item Non-Existent Local Times (DST)
+
+=back
+
+=item IMPLEMENTATION
+
+=item BUGS
+
+=item SUPPORT
+
+=item COPYRIGHT
+
+=item AUTHOR
+
+=back
+
+=head2 Time::Piece - Object Oriented time objects
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item USAGE
+
+=over 4
+
+=item Local Locales
+
+=item Date Calculations
+
+=item Date Comparisons
+
+=item Date Parsing
+
+=item YYYY-MM-DDThh:mm:ss
+
+=item Week Number
+
+=item Global Overriding
+
+=back
+
+=item CAVEATS
+
+=over 4
+
+=item Setting $ENV{TZ} in Threads on Win32
+
+=back
+
+=item AUTHOR
+
+=item License
+
+=item SEE ALSO
+
+=item BUGS
+
+=back
+
+=head2 Time::Seconds - a simple API to convert seconds to other date values
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item METHODS
+
+=item AUTHOR
+
+=item LICENSE
+
+=item Bugs
+
+=back
+
+=head2 Time::gmtime - by-name interface to Perl's built-in gmtime()
+function
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Time::localtime - by-name interface to Perl's built-in localtime()
+function
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 Time::tm - internal object used by Time::gmtime and Time::localtime
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item AUTHOR
+
+=back
+
+=head2 UNIVERSAL - base class for ALL classes (blessed references)
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+C<< $obj->isa( TYPE ) >>, C<< CLASS->isa( TYPE ) >>, C<< eval { VAL->isa(
+TYPE ) } >>, C<TYPE>, C<$obj>, C<CLASS>, C<VAL>, C<< $obj->DOES( ROLE ) >>,
+C<< CLASS->DOES( ROLE ) >>, C<< $obj->can( METHOD ) >>, C<< CLASS->can(
+METHOD ) >>, C<< eval { VAL->can( METHOD ) } >>, C<VERSION ( [ REQUIRE ] )>
+
+=item WARNINGS
+
+=item EXPORTS
+
+=back
+
+=head2 Unicode::Collate - Unicode Collation Algorithm
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Constructor and Tailoring
+
+UCA_Version, alternate, backwards, entry, hangul_terminator, ignoreChar,
+ignoreName, katakana_before_hiragana, level, normalization, overrideCJK,
+overrideHangul, preprocess, rearrange, table, undefChar, undefName,
+upper_before_lower, variable
+
+=item Methods for Collation
+
+C<@sorted = $Collator-E<gt>sort(@not_sorted)>, C<$result =
+$Collator-E<gt>cmp($a, $b)>, C<$result = $Collator-E<gt>eq($a, $b)>,
+C<$result = $Collator-E<gt>ne($a, $b)>, C<$result = $Collator-E<gt>lt($a,
+$b)>, C<$result = $Collator-E<gt>le($a, $b)>, C<$result =
+$Collator-E<gt>gt($a, $b)>, C<$result = $Collator-E<gt>ge($a, $b)>,
+C<$sortKey = $Collator-E<gt>getSortKey($string)>, C<$sortKeyForm =
+$Collator-E<gt>viewSortKey($string)>
+
+=item Methods for Searching
+
+C<$position = $Collator-E<gt>index($string, $substring[, $position])>,
+C<($position, $length) = $Collator-E<gt>index($string, $substring[,
+$position])>, C<$match_ref = $Collator-E<gt>match($string, $substring)>,
+C<($match) = $Collator-E<gt>match($string, $substring)>, C<@match =
+$Collator-E<gt>gmatch($string, $substring)>, C<$count =
+$Collator-E<gt>subst($string, $substring, $replacement)>, C<$count =
+$Collator-E<gt>gsubst($string, $substring, $replacement)>
+
+=item Other Methods
+
+C<%old_tailoring = $Collator-E<gt>change(%new_tailoring)>, C<$version =
+$Collator-E<gt>version()>, C<UCA_Version()>, C<Base_Unicode_Version()>
+
+=back
+
+=item EXPORT
+
+=item INSTALL
+
+=item CAVEATS
+
+Normalization, Conformance Test
+
+=item AUTHOR, COPYRIGHT AND LICENSE
+
+=item SEE ALSO
+
+Unicode Collation Algorithm - UTS #10, The Default Unicode Collation
+Element Table (DUCET), The conformance test for the UCA, Hangul Syllable
+Type, Unicode Normalization Forms - UAX #15
+
+=back
+
+=head2 Unicode::Normalize - Unicode Normalization Forms
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Normalization Forms
+
+C<$NFD_string = NFD($string)>, C<$NFC_string = NFC($string)>,
+C<$NFKD_string = NFKD($string)>, C<$NFKC_string = NFKC($string)>,
+C<$FCD_string = FCD($string)>, C<$FCC_string = FCC($string)>,
+C<$normalized_string = normalize($form_name, $string)>
+
+=item Decomposition and Composition
+
+C<$decomposed_string = decompose($string [, $useCompatMapping])>,
+C<$reordered_string = reorder($string)>, C<$composed_string =
+compose($string)>
+
+=item Quick Check
+
+C<$result = checkNFD($string)>, C<$result = checkNFC($string)>, C<$result =
+checkNFKD($string)>, C<$result = checkNFKC($string)>, C<$result =
+checkFCD($string)>, C<$result = checkFCC($string)>, C<$result =
+check($form_name, $string)>
+
+=item Character Data
+
+C<$canonical_decomposition = getCanon($code_point)>,
+C<$compatibility_decomposition = getCompat($code_point)>,
+C<$code_point_composite = getComposite($code_point_here,
+$code_point_next)>, C<$combining_class = getCombinClass($code_point)>,
+C<$may_be_composed_with_prev_char = isComp2nd($code_point)>,
+C<$is_exclusion = isExclusion($code_point)>, C<$is_singleton =
+isSingleton($code_point)>, C<$is_non_starter_decomposition =
+isNonStDecomp($code_point)>, C<$is_Full_Composition_Exclusion =
+isComp_Ex($code_point)>, C<$NFD_is_NO = isNFD_NO($code_point)>,
+C<$NFC_is_NO = isNFC_NO($code_point)>, C<$NFC_is_MAYBE =
+isNFC_MAYBE($code_point)>, C<$NFKD_is_NO = isNFKD_NO($code_point)>,
+C<$NFKC_is_NO = isNFKC_NO($code_point)>, C<$NFKC_is_MAYBE =
+isNFKC_MAYBE($code_point)>
+
+=back
+
+=item EXPORT
+
+=item CAVEATS
+
+Perl's version vs. Unicode version, Correction of decomposition mapping,
+Revised definition of canonical composition
+
+=item AUTHOR
+
+=item SEE ALSO
+
+http://www.unicode.org/reports/tr15/,
+http://www.unicode.org/Public/UNIDATA/CompositionExclusions.txt,
+http://www.unicode.org/Public/UNIDATA/DerivedNormalizationProps.txt,
+http://www.unicode.org/Public/UNIDATA/NormalizationCorrections.txt,
+http://www.unicode.org/review/pr-29.html, http://www.unicode.org/notes/tn5/
+
+=back
+
+=head2 Unicode::UCD - Unicode character database
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item code point argument
+
+=item B<charinfo()>
+
+B<code>, B<name>, B<category>, B<combining>, B<bidi>, B<decomposition>,
+B<decimal>, B<digit>, B<numeric>, B<mirrored>, B<unicode10>, B<comment>,
+B<upper>, B<lower>, B<title>, B<block>, B<script>
+
+=back
+
+=back
+
+=over 4
+
+=item B<charblock()>
+
+=back
+
+=over 4
+
+=item B<charscript()>
+
+=back
+
+=over 4
+
+=item B<charblocks()>
+
+=back
+
+=over 4
+
+=item B<charscripts()>
+
+=back
+
+=over 4
+
+=item B<charinrange()>
+
+=back
+
+=over 4
+
+=item B<general_categories()>
+
+=back
+
+=over 4
+
+=item B<bidi_types()>
+
+=back
+
+=over 4
+
+=item B<compexcl()>
+
+=back
+
+=over 4
+
+=item B<casefold()>
+
+B<code>, B<full>, B<simple>, B<mapping>, B<status>, B<*>, B<*>, B<turkic>
+
+=back
+
+=over 4
+
+=item B<casespec()>
+
+B<code>, B<lower>, B<title>, B<lower>, B<condition>
+
+=back
+
+=over 4
+
+=item B<namedseq()>
+
+=back
+
+=over 4
+
+=item Unicode::UCD::UnicodeVersion
+
+=back
+
+=over 4
+
+=item B<Blocks versus Scripts>
+
+=item B<Matching Scripts and Blocks>
+
+=item Implementation Note
+
+=back
+
+=over 4
+
+=item BUGS
+
+=item AUTHOR
+
+=back
+
+=head2 User::grent - by-name interface to Perl's built-in getgr*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=item NOTE
+
+=item AUTHOR
+
+=back
+
+=head2 User::pwent - by-name interface to Perl's built-in getpw*()
+functions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item System Specifics
+
+=back
+
+=item NOTE
+
+=item AUTHOR
+
+=item HISTORY
+
+March 18th, 2000
+
+=back
+
+=head2 VMS-DCLsym, VMS::DCLsym - Perl extension to manipulate DCL symbols
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Tied hash interface
+
+=item Object interface
+
+new, getsym, setsym, delsym, clearcache
+
+=back
+
+=item AUTHOR
+
+=item VERSION
+
+=item BUGS
+
+=back
+
+=head2 VMS-Stdio, VMS::Stdio - standard I/O functions via VMS extensions
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+binmode, flush, getname, remove, rewind, setdef, sync, tmpnam, vmsopen,
+alq=INTEGER, bls=INTEGER, ctx=STRING, bin, cvt, nocvt, rec, stm, xplct,
+deq=INTEGER, dna=FILESPEC, fop=STRING, ctg, cbt, dfw, dlt, tef, cif, sup,
+scf, spl, tmd, tmp, nef, rck, wck, mxv, rwo, pos, rwc, sqo, fsz=INTEGER,
+gbc=INTEGER, mbc=INTEGER, mbf=INTEGER, mrs=INTEGER, rat=STRING, cr, blk,
+ftn, none, prn, rfm=STRING, fix, stm, stmlf, stmcr, var, vfc, udf,
+rop=STRING, asy, cco, cvt, eof, nlk, pmt, pta, rea, rlk, rne, rnf, rrl,
+syncsts, tmo, tpt, ulk, wat, rah, wbh, rtv=INTEGER, shr=STRING, del, get,
+mse, nil, put, upd, upi, tmo=INTEGER, vmssysopen, waitfh, writeof
+
+=item REVISION
+
+=back
+
+=head2 Win32 - Interfaces to some Win32 API Functions
+
+=over 4
+
+=item DESCRIPTION
+
+=over 4
+
+=item Alphabetical Listing of Win32 Functions
+
+Win32::AbortSystemShutdown(MACHINE), Win32::BuildNumber(),
+Win32::CopyFile(FROM, TO, OVERWRITE), Win32::CreateDirectory(DIRECTORY),
+Win32::CreateFile(FILE), Win32::DomainName(),
+Win32::ExpandEnvironmentStrings(STRING), Win32::FormatMessage(ERRORCODE),
+Win32::FsType(), Win32::FreeLibrary(HANDLE),
+Win32::GetANSIPathName(FILENAME), Win32::GetArchName(),
+Win32::GetChipName(), Win32::GetCwd(), Win32::GetCurrentProcessId(),
+Win32::GetCurrentThreadId(), Win32::GetFileVersion(FILENAME),
+Win32::GetFolderPath(FOLDER [, CREATE]), Win32::GetFullPathName(FILENAME),
+Win32::GetLastError(), Win32::GetLongPathName(PATHNAME),
+Win32::GetNextAvailDrive(), Win32::GetOSVersion(), Win32::GetOSName(),
+Win32::GetShortPathName(PATHNAME), Win32::GetProcAddress(INSTANCE,
+PROCNAME), Win32::GetTickCount(), Win32::GuidGen(), Win32::IsAdminUser(),
+Win32::IsWinNT(), Win32::IsWin95(), Win32::LoadLibrary(LIBNAME),
+Win32::LoginName(), Win32::LookupAccountName(SYSTEM, ACCOUNT, DOMAIN, SID,
+SIDTYPE), Win32::LookupAccountSID(SYSTEM, SID, ACCOUNT, DOMAIN, SIDTYPE),
+Win32::MsgBox(MESSAGE [, FLAGS [, TITLE]]), Win32::NodeName(),
+Win32::OutputDebugString(STRING), Win32::RegisterServer(LIBRARYNAME),
+Win32::SetChildShowWindow(SHOWWINDOW), Win32::SetCwd(NEWDIRECTORY),
+Win32::SetLastError(ERROR), Win32::Sleep(TIME), Win32::Spawn(COMMAND, ARGS,
+PID), Win32::UnregisterServer(LIBRARYNAME)
+
+=back
+
+=back
+
+=head2 Win32API::File - Low-level access to Win32 system API calls for
+files/dirs.
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Object Oriented/Tied Handle Interface
+
+=item Exports
+
+C<":Func">, attrLetsToBits, C<$uBits= attrLetsToBits( $sAttributeLetters
+)>, C<"a">, C<"c">, C<"h">, C<"o">, C<"r">, C<"s">, C<"t">, createFile,
+C<$hObject= createFile( $sPath )>, C<$hObject= createFile( $sPath,
+$rvhvOptions )>, C<$hObject= createFile( $sPath, $svAccess )>, C<$hObject=
+createFile( $sPath, $svAccess, $rvhvOptions )>, C<$hObject= createFile(
+$sPath, $svAccess, $svShare )>, C<$hObject= createFile( $sPath, $svAccess,
+$svShare, $rvhvOptions )>, C<"q">, C<"r">, C<"w">, C<"k">, C<"t">, C<"n">,
+C<"c">, C<"e">, C<"kc">, C<"ke">, C<"tc">, C<"te">, C<"nc">, C<"ne">, Flags
+=> $uFlags, Attributes => $sAttributes, Security => $pSecurityAttributes,
+Model => $hModelFile, Access => $sAccess, Access => $uAccess, Create =>
+$sCreate, Create => $uCreate, Share => $sShare, Share => $uShare,
+getLogicalDrives, C<@roots= getLogicalDrives()>, CloseHandle,
+C<CloseHandle( $hObject )>, CopyFile, C<CopyFile( $sOldFileName,
+$sNewFileName, $bFailIfExists )>, CreateFile, C<$hObject= CreateFile(
+$sPath, $uAccess, $uShare, $pSecAttr, $uCreate, $uFlags, $hModel )>,
+C<"//./PhysicalDrive0">, C<"//./C:">, C<"//./A:">, C<"//./PIPE/PipeName">,
+DefineDosDevice, C<DefineDosDevice( $uFlags, $sDosDeviceName, $sTargetPath
+)>, C<DDD_RAW_TARGET_PATH>, C<DDD_REMOVE_DEFINITION>,
+C<DDD_EXACT_MATCH_ON_REMOVE>, DeleteFile, C<DeleteFile( $sFileName )>,
+DeviceIoControl, C<DeviceIoControl( $hDevice, $uIoControlCode, $pInBuf,
+$lInBuf, $opOutBuf, $lOutBuf, $olRetBytes, $pOverlapped )>, FdGetOsFHandle,
+C<$hNativeHandle= FdGetOsFHandle( $ivFd )>, fileConstant, C<$value=
+fileConstant( $sConstantName )>, fileLastError, C<$svError=
+fileLastError();>, C<fileLastError( $uError );>, GetDriveType,
+C<$uDriveType= GetDriveType( $sRootPath )>, C<DRIVE_UNKNOWN>,
+C<DRIVE_NO_ROOT_DIR>, C<DRIVE_REMOVABLE>, C<DRIVE_FIXED>, C<DRIVE_REMOTE>,
+C<DRIVE_CDROM>, C<DRIVE_RAMDISK>, GetFileAttributes, C<$uAttrs =
+GetFileAttributes( $sPath )>, C<FILE_ATTRIBUTE_ARCHIVE>,
+C<FILE_ATTRIBUTE_COMPRESSED>, C<FILE_ATTRIBUTE_DEVICE>,
+C<FILE_ATTRIBUTE_DIRECTORY>, C<FILE_ATTRIBUTE_ENCRYPTED>,
+C<FILE_ATTRIBUTE_HIDDEN>, C<FILE_ATTRIBUTE_NORMAL>,
+C<FILE_ATTRIBUTE_NOT_CONTENT_INDEXED>, C<FILE_ATTRIBUTE_OFFLINE>,
+C<FILE_ATTRIBUTE_READONLY>, C<FILE_ATTRIBUTE_REPARSE_POINT>,
+C<FILE_ATTRIBUTE_SPARSE_FILE>, C<FILE_ATTRIBUTE_SYSTEM>,
+C<FILE_ATTRIBUTE_TEMPORARY>, GetFileType, C<$uFileType= GetFileType( $hFile
+)>, C<FILE_TYPE_UNKNOWN>, C<FILE_TYPE_DISK>, C<FILE_TYPE_CHAR>,
+C<FILE_TYPE_PIPE>, getFileSize, C<$size= getFileSize( $hFile )>,
+GetFileSize, C<$iSizeLow= GetFileSize($win32Handle, $iSizeHigh)>,
+GetOverlappedResult, C<$bRetval= GetOverlappedResult( $win32Handle,
+$pOverlapped, $numBytesTransferred, $bWait )>, GetLogicalDrives,
+C<$uDriveBits= GetLogicalDrives()>, GetLogicalDriveStrings, C<$olOutLength=
+GetLogicalDriveStrings( $lBufSize, $osBuffer )>, GetHandleInformation,
+C<GetHandleInformation( $hObject, $ouFlags )>, GetOsFHandle,
+C<$hNativeHandle= GetOsFHandle( FILE )>, GetVolumeInformation,
+C<GetVolumeInformation( $sRootPath, $osVolName, $lVolName, $ouSerialNum,
+$ouMaxNameLen, $ouFsFlags, $osFsType, $lFsType )>, C<FS_CASE_IS_PRESERVED>,
+C<FS_CASE_SENSITIVE>, C<FS_UNICODE_STORED_ON_DISK>, C<FS_PERSISTENT_ACLS>,
+C<FS_FILE_COMPRESSION>, C<FS_VOL_IS_COMPRESSED>, IsRecognizedPartition,
+C<IsRecognizedPartition( $ivPartitionType )>, IsContainerPartition,
+C<IsContainerPartition( $ivPartitionType )>, MoveFile, C<MoveFile(
+$sOldName, $sNewName )>, MoveFileEx, C<MoveFileEx( $sOldName, $sNewName,
+$uFlags )>, C<MOVEFILE_REPLACE_EXISTING>, C<MOVEFILE_COPY_ALLOWED>,
+C<MOVEFILE_DELAY_UNTIL_REBOOT>, C<MOVEFILE_WRITE_THROUGH>, OsFHandleOpen,
+C<OsFHandleOpen( FILE, $hNativeHandle, $sMode )>, OsFHandleOpenFd, C<$ivFD=
+OsFHandleOpenFd( $hNativeHandle, $uMode )>, QueryDosDevice, C<$olTargetLen=
+QueryDosDevice( $sDosDeviceName, $osTargetPath, $lTargetBuf )>, ReadFile,
+C<ReadFile( $hFile, $opBuffer, $lBytes, $olBytesRead, $pOverlapped )>,
+SetErrorMode, C<$uOldMode= SetErrorMode( $uNewMode )>,
+C<SEM_FAILCRITICALERRORS>, C<SEM_NOALIGNMENTFAULTEXCEPT>,
+C<SEM_NOGPFAULTERRORBOX>, C<SEM_NOOPENFILEERRORBOX>, setFilePointer,
+C<$uNewPos = setFilePointer( $hFile, $ivOffset, $uFromWhere )>,
+SetFilePointer, C<$uNewPos = SetFilePointer( $hFile, $ivOffset,
+$ioivOffsetHigh, $uFromWhere )>, SetHandleInformation,
+C<SetHandleInformation( $hObject, $uMask, $uFlags )>, WriteFile,
+C<WriteFile( $hFile, $pBuffer, $lBytes, $ouBytesWritten, $pOverlapped )>,
+C<":FuncA">, C<":FuncW">, CopyFileW, C<CopyFileW( $swOldFileName,
+$swNewFileName, $bFailIfExists )>, CreateFileW, C<$hObject= CreateFileW(
+$swPath, $uAccess, $uShare, $pSecAttr, $uCreate, $uFlags, $hModel )>,
+DefineDosDeviceW, C<DefineDosDeviceW( $uFlags, $swDosDeviceName,
+$swTargetPath )>, DeleteFileW, C<DeleteFileW( $swFileName )>,
+GetDriveTypeW, C<$uDriveType= GetDriveTypeW( $swRootPath )>,
+GetFileAttributesW, C<$uAttrs= GetFileAttributesW( $swPath )>,
+GetLogicalDriveStringsW, C<$olwOutLength= GetLogicalDriveStringsW(
+$lwBufSize, $oswBuffer )>, GetVolumeInformationW, C<GetVolumeInformationW(
+$swRootPath, $oswVolName, $lwVolName, $ouSerialNum, $ouMaxNameLen,
+$ouFsFlags, $oswFsType, $lwFsType )>, MoveFileW, C<MoveFileW( $swOldName,
+$swNewName )>, MoveFileExW, C<MoveFileExW( $swOldName, $swNewName, $uFlags
+)>, QueryDosDeviceW, C<$olwTargetLen= QueryDosDeviceW( $swDeviceName,
+$oswTargetPath, $lwTargetBuf )>, C<":Misc">, C<":DDD_">, C<":DRIVE_">,
+C<":FILE_">, C<":FILE_ATTRIBUTE_">, C<":FILE_FLAG_">, C<":FILE_SHARE_">,
+C<":FILE_TYPE_">, C<":FS_">, C<":HANDLE_FLAG_">, HANDLE_FLAG_INHERIT,
+HANDLE_FLAG_PROTECT_FROM_CLOSE, C<":IOCTL_STORAGE_">,
+C<IOCTL_STORAGE_CHECK_VERIFY>, C<IOCTL_STORAGE_MEDIA_REMOVAL>,
+C<IOCTL_STORAGE_EJECT_MEDIA>, C<IOCTL_STORAGE_LOAD_MEDIA>,
+C<IOCTL_STORAGE_RESERVE>, C<IOCTL_STORAGE_RELEASE>,
+C<IOCTL_STORAGE_FIND_NEW_DEVICES>, C<IOCTL_STORAGE_GET_MEDIA_TYPES>,
+C<$ucCylsLow[$i]>, C<$ivcCylsHigh[$i]>, C<$uMediaType[$i]>,
+C<$uTracksPerCyl[$i]>, C<$uSectsPerTrack[$i]>, C<$uBytesPerSect[$i]>,
+C<":IOCTL_DISK_">, C<IOCTL_DISK_GET_DRIVE_GEOMETRY>, C<$ucCylsLow>,
+C<$ivcCylsHigh>, C<$uMediaType>, C<$uTracksPerCyl>, C<$uSectsPerTrack>,
+C<$uBytesPerSect>, C<IOCTL_DISK_GET_PARTITION_INFO>, C<$uStartLow> and
+C<$ivStartHigh>, C<$ucHiddenSects>, C<$uPartitionSeqNumber>,
+C<$uPartitionType>, C<$bActive>, C<$bRecognized>, C<$bToRewrite>,
+C<IOCTL_DISK_SET_PARTITION_INFO>, C<IOCTL_DISK_GET_DRIVE_LAYOUT>,
+C<$cPartitions>, C<$uDiskSignature>, C<IOCTL_DISK_GET_MEDIA_TYPES>,
+C<IOCTL_DISK_SET_DRIVE_LAYOUT>, C<IOCTL_DISK_VERIFY>, C<$uStartOffsetLow>
+and C<$ivStartOffsetHigh>, C<$uLength>, C<IOCTL_DISK_FORMAT_TRACKS>,
+C<IOCTL_DISK_REASSIGN_BLOCKS>, C<IOCTL_DISK_PERFORMANCE>,
+C<IOCTL_DISK_IS_WRITABLE>, C<IOCTL_DISK_LOGGING>, DISK_LOGGING_START,
+DISK_LOGGING_STOP, DISK_LOGGING_DUMP, DISK_LOGGING_BINNING,
+C<IOCTL_DISK_FORMAT_TRACKS_EX>, C<IOCTL_DISK_HISTOGRAM_STRUCTURE>,
+C<IOCTL_DISK_HISTOGRAM_DATA>, C<IOCTL_DISK_HISTOGRAM_RESET>,
+C<IOCTL_DISK_REQUEST_STRUCTURE>, C<IOCTL_DISK_REQUEST_DATA>, C<":FSCTL_">,
+C<FSCTL_SET_REPARSE_POINT>, C<FSCTL_GET_REPARSE_POINT>,
+C<FSCTL_DELETE_REPARSE_POINT>, C<":GENERIC_">, C<":MEDIA_TYPE">,
+C<Unknown>, C<F5_1Pt2_512>, C<F3_1Pt44_512>, C<F3_2Pt88_512>,
+C<F3_20Pt8_512>, C<F3_720_512>, C<F5_360_512>, C<F5_320_512>,
+C<F5_320_1024>, C<F5_180_512>, C<F5_160_512>, C<RemovableMedia>,
+C<FixedMedia>, C<F3_120M_512>, C<":MOVEFILE_">, C<":SECURITY_">,
+C<":SEM_">, C<":PARTITION_">, C<":ALL">
+
+=back
+
+=item BUGS
+
+=item AUTHOR
+
+=item SEE ALSO
+
+=back
+
+=head2 Win32CORE - Win32 CORE function stubs
+
+=over 4
+
+=item DESCRIPTION
+
+=item HISTORY
+
+=back
+
+=head2 XS-APItest, XS::APItest - Test the perl C API
+
+=over 4
+
+=item SYNOPSIS
+
+=item ABSTRACT
+
+=item DESCRIPTION
+
+=over 4
+
+=item EXPORT
+
+B<print_double>, B<print_long_double>, B<have_long_double>, B<print_nv>,
+B<print_iv>, B<print_uv>, B<print_int>, B<print_long>, B<print_float>,
+B<call_sv>, B<call_pv>, B<call_method>, B<eval_sv>, B<eval_pv>,
+B<require_pv>
+
+=back
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT AND LICENSE
+
+=back
+
+=head2 XS-APItest-KeywordRPN, XS::APItest::KeywordRPN - write arithmetic
+expressions in RPN
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item RPN expression syntax
+
+C<1234>, C<$foo>, I<A> I<B> C<+>, I<A> I<B> C<->, I<A> I<B> C<*>, I<A> I<B>
+C</>, I<A> I<B> C<%>
+
+=back
+
+=back
+
+=over 4
+
+=item OPERATORS
+
+rpn(EXPRESSION), calcrpn VARIABLE { EXPRESSION }
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHOR
+
+=item COPYRIGHT
+
+=item LICENSE
+
+=back
+
+=head2 XS-Typemap, XS::Typemap - module to test the XS typemaps distributed
+with perl
+
+=over 4
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=back
+
+=over 4
+
+=item NOTES
+
+=item AUTHOR
+
+=back
+
+=head2 XSLoader - Dynamically load C libraries into Perl code
+
+=over 4
+
+=item VERSION
+
+=item SYNOPSIS
+
+=item DESCRIPTION
+
+=over 4
+
+=item Migration from C<DynaLoader>
+
+=item Backward compatible boilerplate
+
+=back
+
+=item Order of initialization: early load()
+
+=over 4
+
+=item The most hairy case
+
+=back
+
+=item DIAGNOSTICS
+
+C<Can't find '%s' symbol in %s>, C<Can't load '%s' for module %s: %s>,
+C<Undefined symbols present after loading %s: %s>,
+C<XSLoader::load('Your::Module', $Your::Module::VERSION)>
+
+=item LIMITATIONS
+
+=item BUGS
+
+=item SEE ALSO
+
+=item AUTHORS
+
+=item COPYRIGHT & LICENSE
+
+=back
+
+=head1 AUXILIARY DOCUMENTATION
+
+Here should be listed all the extra programs' documentation, but they
+don't all have manual pages yet:
+
+=over 4
+
+=item a2p
+
+=item c2ph
+
+=item dprofpp
+
+=item h2ph
+
+=item h2xs
+
+=item perlbug
+
+=item perldoc
+
+=item pl2pm
+
+=item pod2html
+
+=item pod2man
+
+=item s2p
+
+=item splain
+
+=item xsubpp
+
+=back
+
+=head1 AUTHOR
+
+Larry Wall <F<larry@wall.org>>, with the help of oodles
+of other folks.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perltodo.pod b/Master/tlpkg/tlperl/lib/pods/perltodo.pod
new file mode 100644
index 00000000000..0a03bf41752
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltodo.pod
@@ -0,0 +1,1302 @@
+=head1 NAME
+
+perltodo - Perl TO-DO List
+
+=head1 DESCRIPTION
+
+This is a list of wishes for Perl. The most up to date version of this file
+is at http://perl5.git.perl.org/perl.git/blob_plain/HEAD:/pod/perltodo.pod
+
+The tasks we think are smaller or easier are listed first. Anyone is welcome
+to work on any of these, but it's a good idea to first contact
+I<perl5-porters@perl.org> to avoid duplication of effort, and to learn from
+any previous attempts. By all means contact a pumpking privately first if you
+prefer.
+
+Whilst patches to make the list shorter are most welcome, ideas to add to
+the list are also encouraged. Check the perl5-porters archives for past
+ideas, and any discussion about them. One set of archives may be found at:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
+
+What can we offer you in return? Fame, fortune, and everlasting glory? Maybe
+not, but if your patch is incorporated, then we'll add your name to the
+F<AUTHORS> file, which ships in the official distribution. How many other
+programming languages offer you 1 line of immortality?
+
+=head1 Tasks that only need Perl knowledge
+
+=head2 Improve Porting/cmpVERSION.pl to work from git tags
+
+See F<Porting/release_managers_guide.pod> for a bit more detail.
+
+=head2 Migrate t/ from custom TAP generation
+
+Many tests below F<t/> still generate TAP by "hand", rather than using library
+functions. As explained in L<perlhack/Writing a test>, tests in F<t/> are
+written in a particular way to test that more complex constructions actually
+work before using them routinely. Hence they don't use C<Test::More>, but
+instead there is an intentionally simpler library, F<t/test.pl>. However,
+quite a few tests in F<t/> have not been refactored to use it. Refactoring
+any of these tests, one at a time, is a useful thing TODO.
+
+The subdirectories F<base>, F<cmd> and F<comp>, that contain the most
+basic tests, should be excluded from this task.
+
+=head2 Test that regen.pl was run
+
+There are various generated files shipped with the perl distribution, for
+things like header files generate from data. The generation scripts are
+written in perl, and all can be run by F<regen.pl>. However, because they're
+written in perl, we can't run them before we've built perl. We can't run them
+as part of the F<Makefile>, because changing files underneath F<make> confuses
+it completely, and we don't want to run them automatically anyway, as they
+change files shipped by the distribution, something we seek not do to.
+
+If someone changes the data, but forgets to re-run F<regen.pl> then the
+generated files are out of sync. It would be good to have a test in
+F<t/porting> that checks that the generated files are in sync, and fails
+otherwise, to alert someone before they make a poor commit. I suspect that this
+would require adapting the scripts run from F<regen.pl> to have dry-run
+options, and invoking them with these, or by refactoring them into a library
+that does the generation, which can be called by the scripts, and by the test.
+
+=head2 Automate perldelta generation
+
+The perldelta file accompanying each release summaries the major changes.
+It's mostly manually generated currently, but some of that could be
+automated with a bit of perl, specifically the generation of
+
+=over
+
+=item Modules and Pragmata
+
+=item New Documentation
+
+=item New Tests
+
+=back
+
+See F<Porting/how_to_write_a_perldelta.pod> for details.
+
+=head2 Remove duplication of test setup.
+
+Schwern notes, that there's duplication of code - lots and lots of tests have
+some variation on the big block of C<$Is_Foo> checks. We can safely put this
+into a file, change it to build an C<%Is> hash and require it. Maybe just put
+it into F<test.pl>. Throw in the handy tainting subroutines.
+
+=head2 POD -E<gt> HTML conversion in the core still sucks
+
+Which is crazy given just how simple POD purports to be, and how simple HTML
+can be. It's not actually I<as> simple as it sounds, particularly with the
+flexibility POD allows for C<=item>, but it would be good to improve the
+visual appeal of the HTML generated, and to avoid it having any validation
+errors. See also L</make HTML install work>, as the layout of installation tree
+is needed to improve the cross-linking.
+
+The addition of C<Pod::Simple> and its related modules may make this task
+easier to complete.
+
+=head2 Make ExtUtils::ParseXS use strict;
+
+F<lib/ExtUtils/ParseXS.pm> contains this line
+
+ # use strict; # One of these days...
+
+Simply uncomment it, and fix all the resulting issues :-)
+
+The more practical approach, to break the task down into manageable chunks, is
+to work your way though the code from bottom to top, or if necessary adding
+extra C<{ ... }> blocks, and turning on strict within them.
+
+=head2 Make Schwern poorer
+
+We should have tests for everything. When all the core's modules are tested,
+Schwern has promised to donate to $500 to TPF. We may need volunteers to
+hold him upside down and shake vigorously in order to actually extract the
+cash.
+
+=head2 Improve the coverage of the core tests
+
+Use Devel::Cover to ascertain the core modules' test coverage, then add
+tests that are currently missing.
+
+=head2 test B
+
+A full test suite for the B module would be nice.
+
+=head2 A decent benchmark
+
+C<perlbench> seems impervious to any recent changes made to the perl core. It
+would be useful to have a reasonable general benchmarking suite that roughly
+represented what current perl programs do, and measurably reported whether
+tweaks to the core improve, degrade or don't really affect performance, to
+guide people attempting to optimise the guts of perl. Gisle would welcome
+new tests for perlbench.
+
+=head2 fix tainting bugs
+
+Fix the bugs revealed by running the test suite with the C<-t> switch (via
+C<make test.taintwarn>).
+
+=head2 Dual life everything
+
+As part of the "dists" plan, anything that doesn't belong in the smallest perl
+distribution needs to be dual lifed. Anything else can be too. Figure out what
+changes would be needed to package that module and its tests up for CPAN, and
+do so. Test it with older perl releases, and fix the problems you find.
+
+To make a minimal perl distribution, it's useful to look at
+F<t/lib/commonsense.t>.
+
+=head2 Move dual-life pod/*.PL into ext
+
+Nearly all the dual-life modules have been moved to F<ext>. However, we
+still need to move F<pod/*.PL> into their respective directories
+in F<ext/>. They're referenced by (at least) C<plextract> in F<Makefile.SH>
+and C<utils> in F<win32/Makefile> and F<win32/makefile.ml>, and listed
+explicitly in F<win32/pod.mak>, F<vms/descrip_mms.template> and F<utils.lst>
+
+=head2 POSIX memory footprint
+
+Ilya observed that use POSIX; eats memory like there's no tomorrow, and at
+various times worked to cut it down. There is probably still fat to cut out -
+for example POSIX passes Exporter some very memory hungry data structures.
+
+=head2 embed.pl/makedef.pl
+
+There is a script F<embed.pl> that generates several header files to prefix
+all of Perl's symbols in a consistent way, to provide some semblance of
+namespace support in C<C>. Functions are declared in F<embed.fnc>, variables
+in F<interpvar.h>. Quite a few of the functions and variables
+are conditionally declared there, using C<#ifdef>. However, F<embed.pl>
+doesn't understand the C macros, so the rules about which symbols are present
+when is duplicated in F<makedef.pl>. Writing things twice is bad, m'kay.
+It would be good to teach C<embed.pl> to understand the conditional
+compilation, and hence remove the duplication, and the mistakes it has caused.
+
+=head2 use strict; and AutoLoad
+
+Currently if you write
+
+ package Whack;
+ use AutoLoader 'AUTOLOAD';
+ use strict;
+ 1;
+ __END__
+ sub bloop {
+ print join (' ', No, strict, here), "!\n";
+ }
+
+then C<use strict;> isn't in force within the autoloaded subroutines. It would
+be more consistent (and less surprising) to arrange for all lexical pragmas
+in force at the __END__ block to be in force within each autoloaded subroutine.
+
+There's a similar problem with SelfLoader.
+
+=head2 profile installman
+
+The F<installman> script is slow. All it is doing text processing, which we're
+told is something Perl is good at. So it would be nice to know what it is doing
+that is taking so much CPU, and where possible address it.
+
+=head2 enable lexical enabling/disabling of inidvidual warnings
+
+Currently, warnings can only be enabled or disabled by category. There
+are times when it would be useful to quash a single warning, not a
+whole category.
+
+=head1 Tasks that need a little sysadmin-type knowledge
+
+Or if you prefer, tasks that you would learn from, and broaden your skills
+base...
+
+=head2 make HTML install work
+
+There is an C<installhtml> target in the Makefile. It's marked as
+"experimental". It would be good to get this tested, make it work reliably, and
+remove the "experimental" tag. This would include
+
+=over 4
+
+=item 1
+
+Checking that cross linking between various parts of the documentation works.
+In particular that links work between the modules (files with POD in F<lib/>)
+and the core documentation (files in F<pod/>)
+
+=item 2
+
+Work out how to split C<perlfunc> into chunks, preferably one per function
+group, preferably with general case code that could be used elsewhere.
+Challenges here are correctly identifying the groups of functions that go
+together, and making the right named external cross-links point to the right
+page. Things to be aware of are C<-X>, groups such as C<getpwnam> to
+C<endservent>, two or more C<=items> giving the different parameter lists, such
+as
+
+ =item substr EXPR,OFFSET,LENGTH,REPLACEMENT
+ =item substr EXPR,OFFSET,LENGTH
+ =item substr EXPR,OFFSET
+
+and different parameter lists having different meanings. (eg C<select>)
+
+=back
+
+=head2 compressed man pages
+
+Be able to install them. This would probably need a configure test to see how
+the system does compressed man pages (same directory/different directory?
+same filename/different filename), as well as tweaking the F<installman> script
+to compress as necessary.
+
+=head2 Add a code coverage target to the Makefile
+
+Make it easy for anyone to run Devel::Cover on the core's tests. The steps
+to do this manually are roughly
+
+=over 4
+
+=item *
+
+do a normal C<Configure>, but include Devel::Cover as a module to install
+(see F<INSTALL> for how to do this)
+
+=item *
+
+ make perl
+
+=item *
+
+ cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib harness
+
+=item *
+
+Process the resulting Devel::Cover database
+
+=back
+
+This just give you the coverage of the F<.pm>s. To also get the C level
+coverage you need to
+
+=over 4
+
+=item *
+
+Additionally tell C<Configure> to use the appropriate C compiler flags for
+C<gcov>
+
+=item *
+
+ make perl.gcov
+
+(instead of C<make perl>)
+
+=item *
+
+After running the tests run C<gcov> to generate all the F<.gcov> files.
+(Including down in the subdirectories of F<ext/>
+
+=item *
+
+(From the top level perl directory) run C<gcov2perl> on all the C<.gcov> files
+to get their stats into the cover_db directory.
+
+=item *
+
+Then process the Devel::Cover database
+
+=back
+
+It would be good to add a single switch to C<Configure> to specify that you
+wanted to perform perl level coverage, and another to specify C level
+coverage, and have C<Configure> and the F<Makefile> do all the right things
+automatically.
+
+=head2 Make Config.pm cope with differences between built and installed perl
+
+Quite often vendors ship a perl binary compiled with their (pay-for)
+compilers. People install a free compiler, such as gcc. To work out how to
+build extensions, Perl interrogates C<%Config>, so in this situation
+C<%Config> describes compilers that aren't there, and extension building
+fails. This forces people into choosing between re-compiling perl themselves
+using the compiler they have, or only using modules that the vendor ships.
+
+It would be good to find a way teach C<Config.pm> about the installation setup,
+possibly involving probing at install time or later, so that the C<%Config> in
+a binary distribution better describes the installed machine, when the
+installed machine differs from the build machine in some significant way.
+
+=head2 linker specification files
+
+Some platforms mandate that you provide a list of a shared library's external
+symbols to the linker, so the core already has the infrastructure in place to
+do this for generating shared perl libraries. My understanding is that the
+GNU toolchain can accept an optional linker specification file, and restrict
+visibility just to symbols declared in that file. It would be good to extend
+F<makedef.pl> to support this format, and to provide a means within
+C<Configure> to enable it. This would allow Unix users to test that the
+export list is correct, and to build a perl that does not pollute the global
+namespace with private symbols.
+
+=head2 Cross-compile support
+
+Currently C<Configure> understands C<-Dusecrosscompile> option. This option
+arranges for building C<miniperl> for TARGET machine, so this C<miniperl> is
+assumed then to be copied to TARGET machine and used as a replacement of full
+C<perl> executable.
+
+This could be done little differently. Namely C<miniperl> should be built for
+HOST and then full C<perl> with extensions should be compiled for TARGET.
+This, however, might require extra trickery for %Config: we have one config
+first for HOST and then another for TARGET. Tools like MakeMaker will be
+mightily confused. Having around two different types of executables and
+libraries (HOST and TARGET) makes life interesting for Makefiles and
+shell (and Perl) scripts. There is $Config{run}, normally empty, which
+can be used as an execution wrapper. Also note that in some
+cross-compilation/execution environments the HOST and the TARGET do
+not see the same filesystem(s), the $Config{run} may need to do some
+file/directory copying back and forth.
+
+=head2 roffitall
+
+Make F<pod/roffitall> be updated by F<pod/buildtoc>.
+
+=head2 Split "linker" from "compiler"
+
+Right now, Configure probes for two commands, and sets two variables:
+
+=over 4
+
+=item * C<cc> (in F<cc.U>)
+
+This variable holds the name of a command to execute a C compiler which
+can resolve multiple global references that happen to have the same
+name. Usual values are F<cc> and F<gcc>.
+Fervent ANSI compilers may be called F<c89>. AIX has F<xlc>.
+
+=item * C<ld> (in F<dlsrc.U>)
+
+This variable indicates the program to be used to link
+libraries for dynamic loading. On some systems, it is F<ld>.
+On ELF systems, it should be C<$cc>. Mostly, we'll try to respect
+the hint file setting.
+
+=back
+
+There is an implicit historical assumption from around Perl5.000alpha
+something, that C<$cc> is also the correct command for linking object files
+together to make an executable. This may be true on Unix, but it's not true
+on other platforms, and there are a maze of work arounds in other places (such
+as F<Makefile.SH>) to cope with this.
+
+Ideally, we should create a new variable to hold the name of the executable
+linker program, probe for it in F<Configure>, and centralise all the special
+case logic there or in hints files.
+
+A small bikeshed issue remains - what to call it, given that C<$ld> is already
+taken (arguably for the wrong thing now, but on SunOS 4.1 it is the command
+for creating dynamically-loadable modules) and C<$link> could be confused with
+the Unix command line executable of the same name, which does something
+completely different. Andy Dougherty makes the counter argument "In parrot, I
+tried to call the command used to link object files and libraries into an
+executable F<link>, since that's what my vaguely-remembered DOS and VMS
+experience suggested. I don't think any real confusion has ensued, so it's
+probably a reasonable name for perl5 to use."
+
+"Alas, I've always worried that introducing it would make things worse,
+since now the module building utilities would have to look for
+C<$Config{link}> and institute a fall-back plan if it weren't found."
+Although I can see that as confusing, given that C<$Config{d_link}> is true
+when (hard) links are available.
+
+=head2 Configure Windows using PowerShell
+
+Currently, Windows uses hard-coded config files based to build the
+config.h for compiling Perl. Makefiles are also hard-coded and need to be
+hand edited prior to building Perl. While this makes it easy to create a perl.exe
+that works across multiple Windows versions, being able to accurately
+configure a perl.exe for a specific Windows versions and VS C++ would be
+a nice enhancement. With PowerShell available on Windows XP and up, this
+may now be possible. Step 1 might be to investigate whether this is possible
+and use this to clean up our current makefile situation. Step 2 would be to
+see if there would be a way to use our existing metaconfig units to configure a
+Windows Perl or whether we go in a separate direction and make it so. Of
+course, we all know what step 3 is.
+
+=head2 decouple -g and -DDEBUGGING
+
+Currently F<Configure> automatically adds C<-DDEBUGGING> to the C compiler
+flags if it spots C<-g> in the optimiser flags. The pre-processor directive
+C<DEBUGGING> enables F<perl>'s command line C<-D> options, but in the process
+makes F<perl> slower. It would be good to disentangle this logic, so that
+C-level debugging with C<-g> and Perl level debugging with C<-D> can easily
+be enabled independently.
+
+=head1 Tasks that need a little C knowledge
+
+These tasks would need a little C knowledge, but don't need any specific
+background or experience with XS, or how the Perl interpreter works
+
+=head2 Weed out needless PERL_UNUSED_ARG
+
+The C code uses the macro C<PERL_UNUSED_ARG> to stop compilers warning about
+unused arguments. Often the arguments can't be removed, as there is an
+external constraint that determines the prototype of the function, so this
+approach is valid. However, there are some cases where C<PERL_UNUSED_ARG>
+could be removed. Specifically
+
+=over 4
+
+=item *
+
+The prototypes of (nearly all) static functions can be changed
+
+=item *
+
+Unused arguments generated by short cut macros are wasteful - the short cut
+macro used can be changed.
+
+=back
+
+=head2 Modernize the order of directories in @INC
+
+The way @INC is laid out by default, one cannot upgrade core (dual-life)
+modules without overwriting files. This causes problems for binary
+package builders. One possible proposal is laid out in this
+message:
+L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2002-04/msg02380.html>.
+
+=head2 -Duse32bit*
+
+Natively 64-bit systems need neither -Duse64bitint nor -Duse64bitall.
+On these systems, it might be the default compilation mode, and there
+is currently no guarantee that passing no use64bitall option to the
+Configure process will build a 32bit perl. Implementing -Duse32bit*
+options would be nice for perl 5.12.
+
+=head2 Profile Perl - am I hot or not?
+
+The Perl source code is stable enough that it makes sense to profile it,
+identify and optimise the hotspots. It would be good to measure the
+performance of the Perl interpreter using free tools such as cachegrind,
+gprof, and dtrace, and work to reduce the bottlenecks they reveal.
+
+As part of this, the idea of F<pp_hot.c> is that it contains the I<hot> ops,
+the ops that are most commonly used. The idea is that by grouping them, their
+object code will be adjacent in the executable, so they have a greater chance
+of already being in the CPU cache (or swapped in) due to being near another op
+already in use.
+
+Except that it's not clear if these really are the most commonly used ops. So
+as part of exercising your skills with coverage and profiling tools you might
+want to determine what ops I<really> are the most commonly used. And in turn
+suggest evictions and promotions to achieve a better F<pp_hot.c>.
+
+One piece of Perl code that might make a good testbed is F<installman>.
+
+=head2 Allocate OPs from arenas
+
+Currently all new OP structures are individually malloc()ed and free()d.
+All C<malloc> implementations have space overheads, and are now as fast as
+custom allocates so it would both use less memory and less CPU to allocate
+the various OP structures from arenas. The SV arena code can probably be
+re-used for this.
+
+Note that Configuring perl with C<-Accflags=-DPL_OP_SLAB_ALLOC> will use
+Perl_Slab_alloc() to pack optrees into a contiguous block, which is
+probably superior to the use of OP arenas, esp. from a cache locality
+standpoint. See L<Profile Perl - am I hot or not?>.
+
+=head2 Improve win32/wince.c
+
+Currently, numerous functions look virtually, if not completely,
+identical in both C<win32/wince.c> and C<win32/win32.c> files, which can't
+be good.
+
+=head2 Use secure CRT functions when building with VC8 on Win32
+
+Visual C++ 2005 (VC++ 8.x) deprecated a number of CRT functions on the basis
+that they were "unsafe" and introduced differently named secure versions of
+them as replacements, e.g. instead of writing
+
+ FILE* f = fopen(__FILE__, "r");
+
+one should now write
+
+ FILE* f;
+ errno_t err = fopen_s(&f, __FILE__, "r");
+
+Currently, the warnings about these deprecations have been disabled by adding
+-D_CRT_SECURE_NO_DEPRECATE to the CFLAGS. It would be nice to remove that
+warning suppressant and actually make use of the new secure CRT functions.
+
+There is also a similar issue with POSIX CRT function names like fileno having
+been deprecated in favour of ISO C++ conformant names like _fileno. These
+warnings are also currently suppressed by adding -D_CRT_NONSTDC_NO_DEPRECATE. It
+might be nice to do as Microsoft suggest here too, although, unlike the secure
+functions issue, there is presumably little or no benefit in this case.
+
+=head2 Fix POSIX::access() and chdir() on Win32
+
+These functions currently take no account of DACLs and therefore do not behave
+correctly in situations where access is restricted by DACLs (as opposed to the
+read-only attribute).
+
+Furthermore, POSIX::access() behaves differently for directories having the
+read-only attribute set depending on what CRT library is being used. For
+example, the _access() function in the VC6 and VC7 CRTs (wrongly) claim that
+such directories are not writable, whereas in fact all directories are writable
+unless access is denied by DACLs. (In the case of directories, the read-only
+attribute actually only means that the directory cannot be deleted.) This CRT
+bug is fixed in the VC8 and VC9 CRTs (but, of course, the directory may still
+not actually be writable if access is indeed denied by DACLs).
+
+For the chdir() issue, see ActiveState bug #74552:
+http://bugs.activestate.com/show_bug.cgi?id=74552
+
+Therefore, DACLs should be checked both for consistency across CRTs and for
+the correct answer.
+
+(Note that perl's -w operator should not be modified to check DACLs. It has
+been written so that it reflects the state of the read-only attribute, even
+for directories (whatever CRT is being used), for symmetry with chmod().)
+
+=head2 strcat(), strcpy(), strncat(), strncpy(), sprintf(), vsprintf()
+
+Maybe create a utility that checks after each libperl.a creation that
+none of the above (nor sprintf(), vsprintf(), or *SHUDDER* gets())
+ever creep back to libperl.a.
+
+ nm libperl.a | ./miniperl -alne '$o = $F[0] if /:$/; print "$o $F[1]" if $F[0] eq "U" && $F[1] =~ /^(?:strn?c(?:at|py)|v?sprintf|gets)$/'
+
+Note, of course, that this will only tell whether B<your> platform
+is using those naughty interfaces.
+
+=head2 -D_FORTIFY_SOURCE=2, -fstack-protector
+
+Recent glibcs support C<-D_FORTIFY_SOURCE=2> and recent gcc
+(4.1 onwards?) supports C<-fstack-protector>, both of which give
+protection against various kinds of buffer overflow problems.
+These should probably be used for compiling Perl whenever available,
+Configure and/or hints files should be adjusted to probe for the
+availability of these features and enable them as appropriate.
+
+=head2 Arenas for GPs? For MAGIC?
+
+C<struct gp> and C<struct magic> are both currently allocated by C<malloc>.
+It might be a speed or memory saving to change to using arenas. Or it might
+not. It would need some suitable benchmarking first. In particular, C<GP>s
+can probably be changed with minimal compatibility impact (probably nothing
+outside of the core, or even outside of F<gv.c> allocates them), but they
+probably aren't allocated/deallocated often enough for a speed saving. Whereas
+C<MAGIC> is allocated/deallocated more often, but in turn, is also something
+more externally visible, so changing the rules here may bite external code.
+
+=head2 Shared arenas
+
+Several SV body structs are now the same size, notably PVMG and PVGV, PVAV and
+PVHV, and PVCV and PVFM. It should be possible to allocate and return same
+sized bodies from the same actual arena, rather than maintaining one arena for
+each. This could save 4-6K per thread, of memory no longer tied up in the
+not-yet-allocated part of an arena.
+
+
+=head1 Tasks that need a knowledge of XS
+
+These tasks would need C knowledge, and roughly the level of knowledge of
+the perl API that comes from writing modules that use XS to interface to
+C.
+
+=head2 Write an XS cookbook
+
+Create pod/perlxscookbook.pod with short, task-focused 'recipes' in XS that
+demonstrate common tasks and good practices. (Some of these might be
+extracted from perlguts.) The target audience should be XS novices, who need
+more examples than perlguts but something less overwhelming than perlapi.
+Recipes should provide "one pretty good way to do it" instead of TIMTOWTDI.
+
+Rather than focusing on interfacing Perl to C libraries, such a cookbook
+should probably focus on how to optimize Perl routines by re-writing them
+in XS. This will likely be more motivating to those who mostly work in
+Perl but are looking to take the next step into XS.
+
+Deconstructing and explaining some simpler XS modules could be one way to
+bootstrap a cookbook. (List::Util? Class::XSAccessor? Tree::Ternary_XS?)
+Another option could be deconstructing the implementation of some simpler
+functions in op.c.
+
+=head2 Allow XSUBs to inline themselves as OPs
+
+For a simple XSUB, often the subroutine dispatch takes more time than the
+XSUB itself. The tokeniser already has the ability to inline constant
+subroutines - it would be good to provide a way to inline other subroutines.
+
+Specifically, simplest approach looks to be to allow an XSUB to provide an
+alternative implementation of itself as a custom OP. A new flag bit in
+C<CvFLAGS()> would signal to the peephole optimiser to take an optree
+such as this:
+
+ b <@> leave[1 ref] vKP/REFC ->(end)
+ 1 <0> enter ->2
+ 2 <;> nextstate(main 1 -e:1) v:{ ->3
+ a <2> sassign vKS/2 ->b
+ 8 <1> entersub[t2] sKS/TARG,1 ->9
+ - <1> ex-list sK ->8
+ 3 <0> pushmark s ->4
+ 4 <$> const(IV 1) sM ->5
+ 6 <1> rv2av[t1] lKM/1 ->7
+ 5 <$> gv(*a) s ->6
+ - <1> ex-rv2cv sK ->-
+ 7 <$> gv(*x) s/EARLYCV ->8
+ - <1> ex-rv2sv sKRM*/1 ->a
+ 9 <$> gvsv(*b) s ->a
+
+perform the symbol table lookup of C<rv2cv> and C<gv(*x)>, locate the
+pointer to the custom OP that provides the direct implementation, and re-
+write the optree something like:
+
+ b <@> leave[1 ref] vKP/REFC ->(end)
+ 1 <0> enter ->2
+ 2 <;> nextstate(main 1 -e:1) v:{ ->3
+ a <2> sassign vKS/2 ->b
+ 7 <1> custom_x -> 8
+ - <1> ex-list sK ->7
+ 3 <0> pushmark s ->4
+ 4 <$> const(IV 1) sM ->5
+ 6 <1> rv2av[t1] lKM/1 ->7
+ 5 <$> gv(*a) s ->6
+ - <1> ex-rv2cv sK ->-
+ - <$> ex-gv(*x) s/EARLYCV ->7
+ - <1> ex-rv2sv sKRM*/1 ->a
+ 8 <$> gvsv(*b) s ->a
+
+I<i.e.> the C<gv(*)> OP has been nulled and spliced out of the execution
+path, and the C<entersub> OP has been replaced by the custom op.
+
+This approach should provide a measurable speed up to simple XSUBs inside
+tight loops. Initially one would have to write the OP alternative
+implementation by hand, but it's likely that this should be reasonably
+straightforward for the type of XSUB that would benefit the most. Longer
+term, once the run-time implementation is proven, it should be possible to
+progressively update ExtUtils::ParseXS to generate OP implementations for
+some XSUBs.
+
+=head2 Remove the use of SVs as temporaries in dump.c
+
+F<dump.c> contains debugging routines to dump out the contains of perl data
+structures, such as C<SV>s, C<AV>s and C<HV>s. Currently, the dumping code
+B<uses> C<SV>s for its temporary buffers, which was a logical initial
+implementation choice, as they provide ready made memory handling.
+
+However, they also lead to a lot of confusion when it happens that what you're
+trying to debug is seen by the code in F<dump.c>, correctly or incorrectly, as
+a temporary scalar it can use for a temporary buffer. It's also not possible
+to dump scalars before the interpreter is properly set up, such as during
+ithreads cloning. It would be good to progressively replace the use of scalars
+as string accumulation buffers with something much simpler, directly allocated
+by C<malloc>. The F<dump.c> code is (or should be) only producing 7 bit
+US-ASCII, so output character sets are not an issue.
+
+Producing and proving an internal simple buffer allocation would make it easier
+to re-write the internals of the PerlIO subsystem to avoid using C<SV>s for
+B<its> buffers, use of which can cause problems similar to those of F<dump.c>,
+at similar times.
+
+=head2 safely supporting POSIX SA_SIGINFO
+
+Some years ago Jarkko supplied patches to provide support for the POSIX
+SA_SIGINFO feature in Perl, passing the extra data to the Perl signal handler.
+
+Unfortunately, it only works with "unsafe" signals, because under safe
+signals, by the time Perl gets to run the signal handler, the extra
+information has been lost. Moreover, it's not easy to store it somewhere,
+as you can't call mutexs, or do anything else fancy, from inside a signal
+handler.
+
+So it strikes me that we could provide safe SA_SIGINFO support
+
+=over 4
+
+=item 1
+
+Provide global variables for two file descriptors
+
+=item 2
+
+When the first request is made via C<sigaction> for C<SA_SIGINFO>, create a
+pipe, store the reader in one, the writer in the other
+
+=item 3
+
+In the "safe" signal handler (C<Perl_csighandler()>/C<S_raise_signal()>), if
+the C<siginfo_t> pointer non-C<NULL>, and the writer file handle is open,
+
+=over 8
+
+=item 1
+
+serialise signal number, C<struct siginfo_t> (or at least the parts we care
+about) into a small auto char buff
+
+=item 2
+
+C<write()> that (non-blocking) to the writer fd
+
+=over 12
+
+=item 1
+
+if it writes 100%, flag the signal in a counter of "signals on the pipe" akin
+to the current per-signal-number counts
+
+=item 2
+
+if it writes 0%, assume the pipe is full. Flag the data as lost?
+
+=item 3
+
+if it writes partially, croak a panic, as your OS is broken.
+
+=back
+
+=back
+
+=item 4
+
+in the regular C<PERL_ASYNC_CHECK()> processing, if there are "signals on
+the pipe", read the data out, deserialise, build the Perl structures on
+the stack (code in C<Perl_sighandler()>, the "unsafe" handler), and call as
+usual.
+
+=back
+
+I think that this gets us decent C<SA_SIGINFO> support, without the current risk
+of running Perl code inside the signal handler context. (With all the dangers
+of things like C<malloc> corruption that that currently offers us)
+
+For more information see the thread starting with this message:
+http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-03/msg00305.html
+
+=head2 autovivification
+
+Make all autovivification consistent w.r.t LVALUE/RVALUE and strict/no strict;
+
+This task is incremental - even a little bit of work on it will help.
+
+=head2 Unicode in Filenames
+
+chdir, chmod, chown, chroot, exec, glob, link, lstat, mkdir, open,
+opendir, qx, readdir, readlink, rename, rmdir, stat, symlink, sysopen,
+system, truncate, unlink, utime, -X. All these could potentially accept
+Unicode filenames either as input or output (and in the case of system
+and qx Unicode in general, as input or output to/from the shell).
+Whether a filesystem - an operating system pair understands Unicode in
+filenames varies.
+
+Known combinations that have some level of understanding include
+Microsoft NTFS, Apple HFS+ (In Mac OS 9 and X) and Apple UFS (in Mac
+OS X), NFS v4 is rumored to be Unicode, and of course Plan 9. How to
+create Unicode filenames, what forms of Unicode are accepted and used
+(UCS-2, UTF-16, UTF-8), what (if any) is the normalization form used,
+and so on, varies. Finding the right level of interfacing to Perl
+requires some thought. Remember that an OS does not implicate a
+filesystem.
+
+(The Windows -C command flag "wide API support" has been at least
+temporarily retired in 5.8.1, and the -C has been repurposed, see
+L<perlrun>.)
+
+Most probably the right way to do this would be this:
+L</"Virtualize operating system access">.
+
+=head2 Unicode in %ENV
+
+Currently the %ENV entries are always byte strings.
+See L</"Virtualize operating system access">.
+
+=head2 Unicode and glob()
+
+Currently glob patterns and filenames returned from File::Glob::glob()
+are always byte strings. See L</"Virtualize operating system access">.
+
+=head2 use less 'memory'
+
+Investigate trade offs to switch out perl's choices on memory usage.
+Particularly perl should be able to give memory back.
+
+This task is incremental - even a little bit of work on it will help.
+
+=head2 Re-implement C<:unique> in a way that is actually thread-safe
+
+The old implementation made bad assumptions on several levels. A good 90%
+solution might be just to make C<:unique> work to share the string buffer
+of SvPVs. That way large constant strings can be shared between ithreads,
+such as the configuration information in F<Config>.
+
+=head2 Make tainting consistent
+
+Tainting would be easier to use if it didn't take documented shortcuts and
+allow taint to "leak" everywhere within an expression.
+
+=head2 readpipe(LIST)
+
+system() accepts a LIST syntax (and a PROGRAM LIST syntax) to avoid
+running a shell. readpipe() (the function behind qx//) could be similarly
+extended.
+
+=head2 Audit the code for destruction ordering assumptions
+
+Change 25773 notes
+
+ /* Need to check SvMAGICAL, as during global destruction it may be that
+ AvARYLEN(av) has been freed before av, and hence the SvANY() pointer
+ is now part of the linked list of SV heads, rather than pointing to
+ the original body. */
+ /* FIXME - audit the code for other bugs like this one. */
+
+adding the C<SvMAGICAL> check to
+
+ if (AvARYLEN(av) && SvMAGICAL(AvARYLEN(av))) {
+ MAGIC *mg = mg_find (AvARYLEN(av), PERL_MAGIC_arylen);
+
+Go through the core and look for similar assumptions that SVs have particular
+types, as all bets are off during global destruction.
+
+=head2 Extend PerlIO and PerlIO::Scalar
+
+PerlIO::Scalar doesn't know how to truncate(). Implementing this
+would require extending the PerlIO vtable.
+
+Similarly the PerlIO vtable doesn't know about formats (write()), or
+about stat(), or chmod()/chown(), utime(), or flock().
+
+(For PerlIO::Scalar it's hard to see what e.g. mode bits or ownership
+would mean.)
+
+PerlIO doesn't do directories or symlinks, either: mkdir(), rmdir(),
+opendir(), closedir(), seekdir(), rewinddir(), glob(); symlink(),
+readlink().
+
+See also L</"Virtualize operating system access">.
+
+=head2 -C on the #! line
+
+It should be possible to make -C work correctly if found on the #! line,
+given that all perl command line options are strict ASCII, and -C changes
+only the interpretation of non-ASCII characters, and not for the script file
+handle. To make it work needs some investigation of the ordering of function
+calls during startup, and (by implication) a bit of tweaking of that order.
+
+=head2 Organize error messages
+
+Perl's diagnostics (error messages, see L<perldiag>) could use
+reorganizing and formalizing so that each error message has its
+stable-for-all-eternity unique id, categorized by severity, type, and
+subsystem. (The error messages would be listed in a datafile outside
+of the Perl source code, and the source code would only refer to the
+messages by the id.) This clean-up and regularizing should apply
+for all croak() messages.
+
+This would enable all sorts of things: easier translation/localization
+of the messages (though please do keep in mind the caveats of
+L<Locale::Maketext> about too straightforward approaches to
+translation), filtering by severity, and instead of grepping for a
+particular error message one could look for a stable error id. (Of
+course, changing the error messages by default would break all the
+existing software depending on some particular error message...)
+
+This kind of functionality is known as I<message catalogs>. Look for
+inspiration for example in the catgets() system, possibly even use it
+if available-- but B<only> if available, all platforms will B<not>
+have catgets().
+
+For the really pure at heart, consider extending this item to cover
+also the warning messages (see L<perllexwarn>, C<warnings.pl>).
+
+=head1 Tasks that need a knowledge of the interpreter
+
+These tasks would need C knowledge, and knowledge of how the interpreter works,
+or a willingness to learn.
+
+=head2 forbid labels with keyword names
+
+Currently C<goto keyword> "computes" the label value:
+
+ $ perl -e 'goto print'
+ Can't find label 1 at -e line 1.
+
+It is controversial if the right way to avoid the confusion is to forbid
+labels with keyword names, or if it would be better to always treat
+bareword expressions after a "goto" as a label and never as a keyword.
+
+=head2 truncate() prototype
+
+The prototype of truncate() is currently C<$$>. It should probably
+be C<*$> instead. (This is changed in F<opcode.pl>)
+
+=head2 decapsulation of smart match argument
+
+Currently C<$foo ~~ $object> will die with the message "Smart matching a
+non-overloaded object breaks encapsulation". It would be nice to allow
+to bypass this by using explictly the syntax C<$foo ~~ %$object> or
+C<$foo ~~ @$object>.
+
+=head2 error reporting of [$a ; $b]
+
+Using C<;> inside brackets is a syntax error, and we don't propose to change
+that by giving it any meaning. However, it's not reported very helpfully:
+
+ $ perl -e '$a = [$b; $c];'
+ syntax error at -e line 1, near "$b;"
+ syntax error at -e line 1, near "$c]"
+ Execution of -e aborted due to compilation errors.
+
+It should be possible to hook into the tokeniser or the lexer, so that when a
+C<;> is parsed where it is not legal as a statement terminator (ie inside
+C<{}> used as a hashref, C<[]> or C<()>) it issues an error something like
+I<';' isn't legal inside an expression - if you need multiple statements use a
+do {...} block>. See the thread starting at
+http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-09/msg00573.html
+
+=head2 lexicals used only once
+
+This warns:
+
+ $ perl -we '$pie = 42'
+ Name "main::pie" used only once: possible typo at -e line 1.
+
+This does not:
+
+ $ perl -we 'my $pie = 42'
+
+Logically all lexicals used only once should warn, if the user asks for
+warnings. An unworked RT ticket (#5087) has been open for almost seven
+years for this discrepancy.
+
+=head2 UTF-8 revamp
+
+The handling of Unicode is unclean in many places. For example, the regexp
+engine matches in Unicode semantics whenever the string or the pattern is
+flagged as UTF-8, but that should not be dependent on an internal storage
+detail of the string.
+
+=head2 Properly Unicode safe tokeniser and pads.
+
+The tokeniser isn't actually very UTF-8 clean. C<use utf8;> is a hack -
+variable names are stored in stashes as raw bytes, without the utf-8 flag
+set. The pad API only takes a C<char *> pointer, so that's all bytes too. The
+tokeniser ignores the UTF-8-ness of C<PL_rsfp>, or any SVs returned from
+source filters. All this could be fixed.
+
+=head2 state variable initialization in list context
+
+Currently this is illegal:
+
+ state ($a, $b) = foo();
+
+In Perl 6, C<state ($a) = foo();> and C<(state $a) = foo();> have different
+semantics, which is tricky to implement in Perl 5 as currently they produce
+the same opcode trees. The Perl 6 design is firm, so it would be good to
+implement the necessary code in Perl 5. There are comments in
+C<Perl_newASSIGNOP()> that show the code paths taken by various assignment
+constructions involving state variables.
+
+=head2 Implement $value ~~ 0 .. $range
+
+It would be nice to extend the syntax of the C<~~> operator to also
+understand numeric (and maybe alphanumeric) ranges.
+
+=head2 A does() built-in
+
+Like ref(), only useful. It would call the C<DOES> method on objects; it
+would also tell whether something can be dereferenced as an
+array/hash/etc., or used as a regexp, etc.
+L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-03/msg00481.html>
+
+=head2 Tied filehandles and write() don't mix
+
+There is no method on tied filehandles to allow them to be called back by
+formats.
+
+=head2 Propagate compilation hints to the debugger
+
+Currently a debugger started with -dE on the command-line doesn't see the
+features enabled by -E. More generally hints (C<$^H> and C<%^H>) aren't
+propagated to the debugger. Probably it would be a good thing to propagate
+hints from the innermost non-C<DB::> scope: this would make code eval'ed
+in the debugger see the features (and strictures, etc.) currently in
+scope.
+
+=head2 Attach/detach debugger from running program
+
+The old perltodo notes "With C<gdb>, you can attach the debugger to a running
+program if you pass the process ID. It would be good to do this with the Perl
+debugger on a running Perl program, although I'm not sure how it would be
+done." ssh and screen do this with named pipes in /tmp. Maybe we can too.
+
+=head2 LVALUE functions for lists
+
+The old perltodo notes that lvalue functions don't work for list or hash
+slices. This would be good to fix.
+
+=head2 regexp optimiser optional
+
+The regexp optimiser is not optional. It should configurable to be, to allow
+its performance to be measured, and its bugs to be easily demonstrated.
+
+=head2 C</w> regex modifier
+
+That flag would enable to match whole words, and also to interpolate
+arrays as alternations. With it, C</P/w> would be roughly equivalent to:
+
+ do { local $"='|'; /\b(?:P)\b/ }
+
+See L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-01/msg00400.html>
+for the discussion.
+
+=head2 optional optimizer
+
+Make the peephole optimizer optional. Currently it performs two tasks as
+it walks the optree - genuine peephole optimisations, and necessary fixups of
+ops. It would be good to find an efficient way to switch out the
+optimisations whilst keeping the fixups.
+
+=head2 You WANT *how* many
+
+Currently contexts are void, scalar and list. split has a special mechanism in
+place to pass in the number of return values wanted. It would be useful to
+have a general mechanism for this, backwards compatible and little speed hit.
+This would allow proposals such as short circuiting sort to be implemented
+as a module on CPAN.
+
+=head2 lexical aliases
+
+Allow lexical aliases (maybe via the syntax C<my \$alias = \$foo>.
+
+=head2 entersub XS vs Perl
+
+At the moment pp_entersub is huge, and has code to deal with entering both
+perl and XS subroutines. Subroutine implementations rarely change between
+perl and XS at run time, so investigate using 2 ops to enter subs (one for
+XS, one for perl) and swap between if a sub is redefined.
+
+=head2 Self-ties
+
+Self-ties are currently illegal because they caused too many segfaults. Maybe
+the causes of these could be tracked down and self-ties on all types
+reinstated.
+
+=head2 Optimize away @_
+
+The old perltodo notes "Look at the "reification" code in C<av.c>".
+
+=head2 Virtualize operating system access
+
+Implement a set of "vtables" that virtualizes operating system access
+(open(), mkdir(), unlink(), readdir(), getenv(), etc.) At the very
+least these interfaces should take SVs as "name" arguments instead of
+bare char pointers; probably the most flexible and extensible way
+would be for the Perl-facing interfaces to accept HVs. The system
+needs to be per-operating-system and per-file-system
+hookable/filterable, preferably both from XS and Perl level
+(L<perlport/"Files and Filesystems"> is good reading at this point,
+in fact, all of L<perlport> is.)
+
+This has actually already been implemented (but only for Win32),
+take a look at F<iperlsys.h> and F<win32/perlhost.h>. While all Win32
+variants go through a set of "vtables" for operating system access,
+non-Win32 systems currently go straight for the POSIX/Unix-style
+system/library call. Similar system as for Win32 should be
+implemented for all platforms. The existing Win32 implementation
+probably does not need to survive alongside this proposed new
+implementation, the approaches could be merged.
+
+What would this give us? One often-asked-for feature this would
+enable is using Unicode for filenames, and other "names" like %ENV,
+usernames, hostnames, and so forth.
+(See L<perlunicode/"When Unicode Does Not Happen">.)
+
+But this kind of virtualization would also allow for things like
+virtual filesystems, virtual networks, and "sandboxes" (though as long
+as dynamic loading of random object code is allowed, not very safe
+sandboxes since external code of course know not of Perl's vtables).
+An example of a smaller "sandbox" is that this feature can be used to
+implement per-thread working directories: Win32 already does this.
+
+See also L</"Extend PerlIO and PerlIO::Scalar">.
+
+=head2 Investigate PADTMP hash pessimisation
+
+The peephole optimiser converts constants used for hash key lookups to shared
+hash key scalars. Under ithreads, something is undoing this work.
+See http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2007-09/msg00793.html
+
+=head2 Store the current pad in the OP slab allocator
+
+=for clarification
+I hope that I got that "current pad" part correct
+
+Currently we leak ops in various cases of parse failure. I suggested that we
+could solve this by always using the op slab allocator, and walking it to
+free ops. Dave comments that as some ops are already freed during optree
+creation one would have to mark which ops are freed, and not double free them
+when walking the slab. He notes that one problem with this is that for some ops
+you have to know which pad was current at the time of allocation, which does
+change. I suggested storing a pointer to the current pad in the memory allocated
+for the slab, and swapping to a new slab each time the pad changes. Dave thinks
+that this would work.
+
+=head2 repack the optree
+
+Repacking the optree after execution order is determined could allow
+removal of NULL ops, and optimal ordering of OPs with respect to cache-line
+filling. The slab allocator could be reused for this purpose. I think that
+the best way to do this is to make it an optional step just before the
+completed optree is attached to anything else, and to use the slab allocator
+unchanged, so that freeing ops is identical whether or not this step runs.
+Note that the slab allocator allocates ops downwards in memory, so one would
+have to actually "allocate" the ops in reverse-execution order to get them
+contiguous in memory in execution order.
+
+See http://www.nntp.perl.org/group/perl.perl5.porters/2007/12/msg131975.html
+
+Note that running this copy, and then freeing all the old location ops would
+cause their slabs to be freed, which would eliminate possible memory wastage if
+the previous suggestion is implemented, and we swap slabs more frequently.
+
+=head2 eliminate incorrect line numbers in warnings
+
+This code
+
+ use warnings;
+ my $undef;
+
+ if ($undef == 3) {
+ } elsif ($undef == 0) {
+ }
+
+used to produce this output:
+
+ Use of uninitialized value in numeric eq (==) at wrong.pl line 4.
+ Use of uninitialized value in numeric eq (==) at wrong.pl line 4.
+
+where the line of the second warning was misreported - it should be line 5.
+Rafael fixed this - the problem arose because there was no nextstate OP
+between the execution of the C<if> and the C<elsif>, hence C<PL_curcop> still
+reports that the currently executing line is line 4. The solution was to inject
+a nextstate OPs for each C<elsif>, although it turned out that the nextstate
+OP needed to be a nulled OP, rather than a live nextstate OP, else other line
+numbers became misreported. (Jenga!)
+
+The problem is more general than C<elsif> (although the C<elsif> case is the
+most common and the most confusing). Ideally this code
+
+ use warnings;
+ my $undef;
+
+ my $a = $undef + 1;
+ my $b
+ = $undef
+ + 1;
+
+would produce this output
+
+ Use of uninitialized value $undef in addition (+) at wrong.pl line 4.
+ Use of uninitialized value $undef in addition (+) at wrong.pl line 7.
+
+(rather than lines 4 and 5), but this would seem to require every OP to carry
+(at least) line number information.
+
+What might work is to have an optional line number in memory just before the
+BASEOP structure, with a flag bit in the op to say whether it's present.
+Initially during compile every OP would carry its line number. Then add a late
+pass to the optimiser (potentially combined with L</repack the optree>) which
+looks at the two ops on every edge of the graph of the execution path. If
+the line number changes, flags the destination OP with this information.
+Once all paths are traced, replace every op with the flag with a
+nextstate-light op (that just updates C<PL_curcop>), which in turn then passes
+control on to the true op. All ops would then be replaced by variants that
+do not store the line number. (Which, logically, why it would work best in
+conjunction with L</repack the optree>, as that is already copying/reallocating
+all the OPs)
+
+(Although I should note that we're not certain that doing this for the general
+case is worth it)
+
+=head2 optimize tail-calls
+
+Tail-calls present an opportunity for broadly applicable optimization;
+anywhere that C<< return foo(...) >> is called, the outer return can
+be replaced by a goto, and foo will return directly to the outer
+caller, saving (conservatively) 25% of perl's call&return cost, which
+is relatively higher than in C. The scheme language is known to do
+this heavily. B::Concise provides good insight into where this
+optimization is possible, ie anywhere entersub,leavesub op-sequence
+occurs.
+
+ perl -MO=Concise,-exec,a,b,-main -e 'sub a{ 1 }; sub b {a()}; b(2)'
+
+Bottom line on this is probably a new pp_tailcall function which
+combines the code in pp_entersub, pp_leavesub. This should probably
+be done 1st in XS, and using B::Generate to patch the new OP into the
+optrees.
+
+=head1 Big projects
+
+Tasks that will get your name mentioned in the description of the "Highlights
+of 5.12"
+
+=head2 make ithreads more robust
+
+Generally make ithreads more robust. See also L</iCOW>
+
+This task is incremental - even a little bit of work on it will help, and
+will be greatly appreciated.
+
+One bit would be to write the missing code in sv.c:Perl_dirp_dup.
+
+Fix Perl_sv_dup, et al so that threads can return objects.
+
+=head2 iCOW
+
+Sarathy and Arthur have a proposal for an improved Copy On Write which
+specifically will be able to COW new ithreads. If this can be implemented
+it would be a good thing.
+
+=head2 (?{...}) closures in regexps
+
+Fix (or rewrite) the implementation of the C</(?{...})/> closures.
+
+=head2 A re-entrant regexp engine
+
+This will allow the use of a regex from inside (?{ }), (??{ }) and
+(?(?{ })|) constructs.
+
+=head2 Add class set operations to regexp engine
+
+Apparently these are quite useful. Anyway, Jeffery Friedl wants them.
+
+demerphq has this on his todo list, but right at the bottom.
+
+
+=head1 Tasks for microperl
+
+
+[ Each and every one of these may be obsolete, but they were listed
+ in the old Todo.micro file]
+
+
+=head2 make creating uconfig.sh automatic
+
+=head2 make creating Makefile.micro automatic
+
+=head2 do away with fork/exec/wait?
+
+(system, popen should be enough?)
+
+=head2 some of the uconfig.sh really needs to be probed (using cc) in buildtime:
+
+(uConfigure? :-) native datatype widths and endianness come to mind
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perltooc.pod b/Master/tlpkg/tlperl/lib/pods/perltooc.pod
new file mode 100644
index 00000000000..06f697cdef1
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltooc.pod
@@ -0,0 +1,1342 @@
+=head1 NAME
+
+perltooc - Tom's OO Tutorial for Class Data in Perl
+
+=head1 DESCRIPTION
+
+When designing an object class, you are sometimes faced with the situation
+of wanting common state shared by all objects of that class.
+Such I<class attributes> act somewhat like global variables for the entire
+class, but unlike program-wide globals, class attributes have meaning only to
+the class itself.
+
+Here are a few examples where class attributes might come in handy:
+
+=over 4
+
+=item *
+
+to keep a count of the objects you've created, or how many are
+still extant.
+
+=item *
+
+to extract the name or file descriptor for a logfile used by a debugging
+method.
+
+=item *
+
+to access collective data, like the total amount of cash dispensed by
+all ATMs in a network in a given day.
+
+=item *
+
+to access the last object created by a class, or the most accessed object,
+or to retrieve a list of all objects.
+
+=back
+
+Unlike a true global, class attributes should not be accessed directly.
+Instead, their state should be inspected, and perhaps altered, only
+through the mediated access of I<class methods>. These class attributes
+accessor methods are similar in spirit and function to accessors used
+to manipulate the state of instance attributes on an object. They provide a
+clear firewall between interface and implementation.
+
+You should allow access to class attributes through either the class
+name or any object of that class. If we assume that $an_object is of
+type Some_Class, and the &Some_Class::population_count method accesses
+class attributes, then these two invocations should both be possible,
+and almost certainly equivalent.
+
+ Some_Class->population_count()
+ $an_object->population_count()
+
+The question is, where do you store the state which that method accesses?
+Unlike more restrictive languages like C++, where these are called
+static data members, Perl provides no syntactic mechanism to declare
+class attributes, any more than it provides a syntactic mechanism to
+declare instance attributes. Perl provides the developer with a broad
+set of powerful but flexible features that can be uniquely crafted to
+the particular demands of the situation.
+
+A class in Perl is typically implemented in a module. A module consists
+of two complementary feature sets: a package for interfacing with the
+outside world, and a lexical file scope for privacy. Either of these
+two mechanisms can be used to implement class attributes. That means you
+get to decide whether to put your class attributes in package variables
+or to put them in lexical variables.
+
+And those aren't the only decisions to make. If you choose to use package
+variables, you can make your class attribute accessor methods either ignorant
+of inheritance or sensitive to it. If you choose lexical variables,
+you can elect to permit access to them from anywhere in the entire file
+scope, or you can limit direct data access exclusively to the methods
+implementing those attributes.
+
+=head1 Class Data in a Can
+
+One of the easiest ways to solve a hard problem is to let someone else
+do it for you! In this case, Class::Data::Inheritable (available on a
+CPAN near you) offers a canned solution to the class data problem
+using closures. So before you wade into this document, consider
+having a look at that module.
+
+
+=head1 Class Data as Package Variables
+
+Because a class in Perl is really just a package, using package variables
+to hold class attributes is the most natural choice. This makes it simple
+for each class to have its own class attributes. Let's say you have a class
+called Some_Class that needs a couple of different attributes that you'd
+like to be global to the entire class. The simplest thing to do is to
+use package variables like $Some_Class::CData1 and $Some_Class::CData2
+to hold these attributes. But we certainly don't want to encourage
+outsiders to touch those data directly, so we provide methods
+to mediate access.
+
+In the accessor methods below, we'll for now just ignore the first
+argument--that part to the left of the arrow on method invocation, which
+is either a class name or an object reference.
+
+ package Some_Class;
+ sub CData1 {
+ shift; # XXX: ignore calling class/object
+ $Some_Class::CData1 = shift if @_;
+ return $Some_Class::CData1;
+ }
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ $Some_Class::CData2 = shift if @_;
+ return $Some_Class::CData2;
+ }
+
+This technique is highly legible and should be completely straightforward
+to even the novice Perl programmer. By fully qualifying the package
+variables, they stand out clearly when reading the code. Unfortunately,
+if you misspell one of these, you've introduced an error that's hard
+to catch. It's also somewhat disconcerting to see the class name itself
+hard-coded in so many places.
+
+Both these problems can be easily fixed. Just add the C<use strict>
+pragma, then pre-declare your package variables. (The C<our> operator
+will be new in 5.6, and will work for package globals just like C<my>
+works for scoped lexicals.)
+
+ package Some_Class;
+ use strict;
+ our($CData1, $CData2); # our() is new to perl5.6
+ sub CData1 {
+ shift; # XXX: ignore calling class/object
+ $CData1 = shift if @_;
+ return $CData1;
+ }
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ $CData2 = shift if @_;
+ return $CData2;
+ }
+
+
+As with any other global variable, some programmers prefer to start their
+package variables with capital letters. This helps clarity somewhat, but
+by no longer fully qualifying the package variables, their significance
+can be lost when reading the code. You can fix this easily enough by
+choosing better names than were used here.
+
+=head2 Putting All Your Eggs in One Basket
+
+Just as the mindless enumeration of accessor methods for instance attributes
+grows tedious after the first few (see L<perltoot>), so too does the
+repetition begin to grate when listing out accessor methods for class
+data. Repetition runs counter to the primary virtue of a programmer:
+Laziness, here manifesting as that innate urge every programmer feels
+to factor out duplicate code whenever possible.
+
+Here's what to do. First, make just one hash to hold all class attributes.
+
+ package Some_Class;
+ use strict;
+ our %ClassData = ( # our() is new to perl5.6
+ CData1 => "",
+ CData2 => "",
+ );
+
+Using closures (see L<perlref>) and direct access to the package symbol
+table (see L<perlmod>), now clone an accessor method for each key in
+the %ClassData hash. Each of these methods is used to fetch or store
+values to the specific, named class attribute.
+
+ for my $datum (keys %ClassData) {
+ no strict "refs"; # to register new methods in package
+ *$datum = sub {
+ shift; # XXX: ignore calling class/object
+ $ClassData{$datum} = shift if @_;
+ return $ClassData{$datum};
+ }
+ }
+
+It's true that you could work out a solution employing an &AUTOLOAD
+method, but this approach is unlikely to prove satisfactory. Your
+function would have to distinguish between class attributes and object
+attributes; it could interfere with inheritance; and it would have to
+careful about DESTROY. Such complexity is uncalled for in most cases,
+and certainly in this one.
+
+You may wonder why we're rescinding strict refs for the loop. We're
+manipulating the package's symbol table to introduce new function names
+using symbolic references (indirect naming), which the strict pragma
+would otherwise forbid. Normally, symbolic references are a dodgy
+notion at best. This isn't just because they can be used accidentally
+when you aren't meaning to. It's also because for most uses
+to which beginning Perl programmers attempt to put symbolic references,
+we have much better approaches, like nested hashes or hashes of arrays.
+But there's nothing wrong with using symbolic references to manipulate
+something that is meaningful only from the perspective of the package
+symbol table, like method names or package variables. In other
+words, when you want to refer to the symbol table, use symbol references.
+
+Clustering all the class attributes in one place has several advantages.
+They're easy to spot, initialize, and change. The aggregation also
+makes them convenient to access externally, such as from a debugger
+or a persistence package. The only possible problem is that we don't
+automatically know the name of each class's class object, should it have
+one. This issue is addressed below in L<"The Eponymous Meta-Object">.
+
+=head2 Inheritance Concerns
+
+Suppose you have an instance of a derived class, and you access class
+data using an inherited method call. Should that end up referring
+to the base class's attributes, or to those in the derived class?
+How would it work in the earlier examples? The derived class inherits
+all the base class's methods, including those that access class attributes.
+But what package are the class attributes stored in?
+
+The answer is that, as written, class attributes are stored in the package into
+which those methods were compiled. When you invoke the &CData1 method
+on the name of the derived class or on one of that class's objects, the
+version shown above is still run, so you'll access $Some_Class::CData1--or
+in the method cloning version, C<$Some_Class::ClassData{CData1}>.
+
+Think of these class methods as executing in the context of their base
+class, not in that of their derived class. Sometimes this is exactly
+what you want. If Feline subclasses Carnivore, then the population of
+Carnivores in the world should go up when a new Feline is born.
+But what if you wanted to figure out how many Felines you have apart
+from Carnivores? The current approach doesn't support that.
+
+You'll have to decide on a case-by-case basis whether it makes any sense
+for class attributes to be package-relative. If you want it to be so,
+then stop ignoring the first argument to the function. Either it will
+be a package name if the method was invoked directly on a class name,
+or else it will be an object reference if the method was invoked on an
+object reference. In the latter case, the ref() function provides the
+class of that object.
+
+ package Some_Class;
+ sub CData1 {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ my $varname = $class . "::CData1";
+ no strict "refs"; # to access package data symbolically
+ $$varname = shift if @_;
+ return $$varname;
+ }
+
+And then do likewise for all other class attributes (such as CData2,
+etc.) that you wish to access as package variables in the invoking package
+instead of the compiling package as we had previously.
+
+Once again we temporarily disable the strict references ban, because
+otherwise we couldn't use the fully-qualified symbolic name for
+the package global. This is perfectly reasonable: since all package
+variables by definition live in a package, there's nothing wrong with
+accessing them via that package's symbol table. That's what it's there
+for (well, somewhat).
+
+What about just using a single hash for everything and then cloning
+methods? What would that look like? The only difference would be the
+closure used to produce new method entries for the class's symbol table.
+
+ no strict "refs";
+ *$datum = sub {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ my $varname = $class . "::ClassData";
+ $varname->{$datum} = shift if @_;
+ return $varname->{$datum};
+ }
+
+=head2 The Eponymous Meta-Object
+
+It could be argued that the %ClassData hash in the previous example is
+neither the most imaginative nor the most intuitive of names. Is there
+something else that might make more sense, be more useful, or both?
+
+As it happens, yes, there is. For the "class meta-object", we'll use
+a package variable of the same name as the package itself. Within the
+scope of a package Some_Class declaration, we'll use the eponymously
+named hash %Some_Class as that class's meta-object. (Using an eponymously
+named hash is somewhat reminiscent of classes that name their constructors
+eponymously in the Python or C++ fashion. That is, class Some_Class would
+use &Some_Class::Some_Class as a constructor, probably even exporting that
+name as well. The StrNum class in Recipe 13.14 in I<The Perl Cookbook>
+does this, if you're looking for an example.)
+
+This predictable approach has many benefits, including having a well-known
+identifier to aid in debugging, transparent persistence,
+or checkpointing. It's also the obvious name for monadic classes and
+translucent attributes, discussed later.
+
+Here's an example of such a class. Notice how the name of the
+hash storing the meta-object is the same as the name of the package
+used to implement the class.
+
+ package Some_Class;
+ use strict;
+
+ # create class meta-object using that most perfect of names
+ our %Some_Class = ( # our() is new to perl5.6
+ CData1 => "",
+ CData2 => "",
+ );
+
+ # this accessor is calling-package-relative
+ sub CData1 {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ no strict "refs"; # to access eponymous meta-object
+ $class->{CData1} = shift if @_;
+ return $class->{CData1};
+ }
+
+ # but this accessor is not
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ no strict "refs"; # to access eponymous meta-object
+ __PACKAGE__ -> {CData2} = shift if @_;
+ return __PACKAGE__ -> {CData2};
+ }
+
+In the second accessor method, the __PACKAGE__ notation was used for
+two reasons. First, to avoid hardcoding the literal package name
+in the code in case we later want to change that name. Second, to
+clarify to the reader that what matters here is the package currently
+being compiled into, not the package of the invoking object or class.
+If the long sequence of non-alphabetic characters bothers you, you can
+always put the __PACKAGE__ in a variable first.
+
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ no strict "refs"; # to access eponymous meta-object
+ my $class = __PACKAGE__;
+ $class->{CData2} = shift if @_;
+ return $class->{CData2};
+ }
+
+Even though we're using symbolic references for good not evil, some
+folks tend to become unnerved when they see so many places with strict
+ref checking disabled. Given a symbolic reference, you can always
+produce a real reference (the reverse is not true, though). So we'll
+create a subroutine that does this conversion for us. If invoked as a
+function of no arguments, it returns a reference to the compiling class's
+eponymous hash. Invoked as a class method, it returns a reference to
+the eponymous hash of its caller. And when invoked as an object method,
+this function returns a reference to the eponymous hash for whatever
+class the object belongs to.
+
+ package Some_Class;
+ use strict;
+
+ our %Some_Class = ( # our() is new to perl5.6
+ CData1 => "",
+ CData2 => "",
+ );
+
+ # tri-natured: function, class method, or object method
+ sub _classobj {
+ my $obclass = shift || __PACKAGE__;
+ my $class = ref($obclass) || $obclass;
+ no strict "refs"; # to convert sym ref to real one
+ return \%$class;
+ }
+
+ for my $datum (keys %{ _classobj() } ) {
+ # turn off strict refs so that we can
+ # register a method in the symbol table
+ no strict "refs";
+ *$datum = sub {
+ use strict "refs";
+ my $self = shift->_classobj();
+ $self->{$datum} = shift if @_;
+ return $self->{$datum};
+ }
+ }
+
+=head2 Indirect References to Class Data
+
+A reasonably common strategy for handling class attributes is to store
+a reference to each package variable on the object itself. This is
+a strategy you've probably seen before, such as in L<perltoot> and
+L<perlbot>, but there may be variations in the example below that you
+haven't thought of before.
+
+ package Some_Class;
+ our($CData1, $CData2); # our() is new to perl5.6
+
+ sub new {
+ my $obclass = shift;
+ return bless my $self = {
+ ObData1 => "",
+ ObData2 => "",
+ CData1 => \$CData1,
+ CData2 => \$CData2,
+ } => (ref $obclass || $obclass);
+ }
+
+ sub ObData1 {
+ my $self = shift;
+ $self->{ObData1} = shift if @_;
+ return $self->{ObData1};
+ }
+
+ sub ObData2 {
+ my $self = shift;
+ $self->{ObData2} = shift if @_;
+ return $self->{ObData2};
+ }
+
+ sub CData1 {
+ my $self = shift;
+ my $dataref = ref $self
+ ? $self->{CData1}
+ : \$CData1;
+ $$dataref = shift if @_;
+ return $$dataref;
+ }
+
+ sub CData2 {
+ my $self = shift;
+ my $dataref = ref $self
+ ? $self->{CData2}
+ : \$CData2;
+ $$dataref = shift if @_;
+ return $$dataref;
+ }
+
+As written above, a derived class will inherit these methods, which
+will consequently access package variables in the base class's package.
+This is not necessarily expected behavior in all circumstances. Here's an
+example that uses a variable meta-object, taking care to access the
+proper package's data.
+
+ package Some_Class;
+ use strict;
+
+ our %Some_Class = ( # our() is new to perl5.6
+ CData1 => "",
+ CData2 => "",
+ );
+
+ sub _classobj {
+ my $self = shift;
+ my $class = ref($self) || $self;
+ no strict "refs";
+ # get (hard) ref to eponymous meta-object
+ return \%$class;
+ }
+
+ sub new {
+ my $obclass = shift;
+ my $classobj = $obclass->_classobj();
+ bless my $self = {
+ ObData1 => "",
+ ObData2 => "",
+ CData1 => \$classobj->{CData1},
+ CData2 => \$classobj->{CData2},
+ } => (ref $obclass || $obclass);
+ return $self;
+ }
+
+ sub ObData1 {
+ my $self = shift;
+ $self->{ObData1} = shift if @_;
+ return $self->{ObData1};
+ }
+
+ sub ObData2 {
+ my $self = shift;
+ $self->{ObData2} = shift if @_;
+ return $self->{ObData2};
+ }
+
+ sub CData1 {
+ my $self = shift;
+ $self = $self->_classobj() unless ref $self;
+ my $dataref = $self->{CData1};
+ $$dataref = shift if @_;
+ return $$dataref;
+ }
+
+ sub CData2 {
+ my $self = shift;
+ $self = $self->_classobj() unless ref $self;
+ my $dataref = $self->{CData2};
+ $$dataref = shift if @_;
+ return $$dataref;
+ }
+
+Not only are we now strict refs clean, using an eponymous meta-object
+seems to make the code cleaner. Unlike the previous version, this one
+does something interesting in the face of inheritance: it accesses the
+class meta-object in the invoking class instead of the one into which
+the method was initially compiled.
+
+You can easily access data in the class meta-object, making
+it easy to dump the complete class state using an external mechanism such
+as when debugging or implementing a persistent class. This works because
+the class meta-object is a package variable, has a well-known name, and
+clusters all its data together. (Transparent persistence
+is not always feasible, but it's certainly an appealing idea.)
+
+There's still no check that object accessor methods have not been
+invoked on a class name. If strict ref checking is enabled, you'd
+blow up. If not, then you get the eponymous meta-object. What you do
+with--or about--this is up to you. The next two sections demonstrate
+innovative uses for this powerful feature.
+
+=head2 Monadic Classes
+
+Some of the standard modules shipped with Perl provide class interfaces
+without any attribute methods whatsoever. The most commonly used module
+not numbered amongst the pragmata, the Exporter module, is a class with
+neither constructors nor attributes. Its job is simply to provide a
+standard interface for modules wishing to export part of their namespace
+into that of their caller. Modules use the Exporter's &import method by
+setting their inheritance list in their package's @ISA array to mention
+"Exporter". But class Exporter provides no constructor, so you can't
+have several instances of the class. In fact, you can't have any--it
+just doesn't make any sense. All you get is its methods. Its interface
+contains no statefulness, so state data is wholly superfluous.
+
+Another sort of class that pops up from time to time is one that supports
+a unique instance. Such classes are called I<monadic classes>, or less
+formally, I<singletons> or I<highlander classes>.
+
+If a class is monadic, where do you store its state, that is,
+its attributes? How do you make sure that there's never more than
+one instance? While you could merely use a slew of package variables,
+it's a lot cleaner to use the eponymously named hash. Here's a complete
+example of a monadic class:
+
+ package Cosmos;
+ %Cosmos = ();
+
+ # accessor method for "name" attribute
+ sub name {
+ my $self = shift;
+ $self->{name} = shift if @_;
+ return $self->{name};
+ }
+
+ # read-only accessor method for "birthday" attribute
+ sub birthday {
+ my $self = shift;
+ die "can't reset birthday" if @_; # XXX: croak() is better
+ return $self->{birthday};
+ }
+
+ # accessor method for "stars" attribute
+ sub stars {
+ my $self = shift;
+ $self->{stars} = shift if @_;
+ return $self->{stars};
+ }
+
+ # oh my - one of our stars just went out!
+ sub supernova {
+ my $self = shift;
+ my $count = $self->stars();
+ $self->stars($count - 1) if $count > 0;
+ }
+
+ # constructor/initializer method - fix by reboot
+ sub bigbang {
+ my $self = shift;
+ %$self = (
+ name => "the world according to tchrist",
+ birthday => time(),
+ stars => 0,
+ );
+ return $self; # yes, it's probably a class. SURPRISE!
+ }
+
+ # After the class is compiled, but before any use or require
+ # returns, we start off the universe with a bang.
+ __PACKAGE__ -> bigbang();
+
+Hold on, that doesn't look like anything special. Those attribute
+accessors look no different than they would if this were a regular class
+instead of a monadic one. The crux of the matter is there's nothing
+that says that $self must hold a reference to a blessed object. It merely
+has to be something you can invoke methods on. Here the package name
+itself, Cosmos, works as an object. Look at the &supernova method. Is that
+a class method or an object method? The answer is that static analysis
+cannot reveal the answer. Perl doesn't care, and neither should you.
+In the three attribute methods, C<%$self> is really accessing the %Cosmos
+package variable.
+
+If like Stephen Hawking, you posit the existence of multiple, sequential,
+and unrelated universes, then you can invoke the &bigbang method yourself
+at any time to start everything all over again. You might think of
+&bigbang as more of an initializer than a constructor, since the function
+doesn't allocate new memory; it only initializes what's already there.
+But like any other constructor, it does return a scalar value to use
+for later method invocations.
+
+Imagine that some day in the future, you decide that one universe just
+isn't enough. You could write a new class from scratch, but you already
+have an existing class that does what you want--except that it's monadic,
+and you want more than just one cosmos.
+
+That's what code reuse via subclassing is all about. Look how short
+the new code is:
+
+ package Multiverse;
+ use Cosmos;
+ @ISA = qw(Cosmos);
+
+ sub new {
+ my $protoverse = shift;
+ my $class = ref($protoverse) || $protoverse;
+ my $self = {};
+ return bless($self, $class)->bigbang();
+ }
+ 1;
+
+Because we were careful to be good little creators when we designed our
+Cosmos class, we can now reuse it without touching a single line of code
+when it comes time to write our Multiverse class. The same code that
+worked when invoked as a class method continues to work perfectly well
+when invoked against separate instances of a derived class.
+
+The astonishing thing about the Cosmos class above is that the value
+returned by the &bigbang "constructor" is not a reference to a blessed
+object at all. It's just the class's own name. A class name is, for
+virtually all intents and purposes, a perfectly acceptable object.
+It has state, behavior, and identity, the three crucial components
+of an object system. It even manifests inheritance, polymorphism,
+and encapsulation. And what more can you ask of an object?
+
+To understand object orientation in Perl, it's important to recognize the
+unification of what other programming languages might think of as class
+methods and object methods into just plain methods. "Class methods"
+and "object methods" are distinct only in the compartmentalizing mind
+of the Perl programmer, not in the Perl language itself.
+
+Along those same lines, a constructor is nothing special either, which
+is one reason why Perl has no pre-ordained name for them. "Constructor"
+is just an informal term loosely used to describe a method that returns
+a scalar value that you can make further method calls against. So long
+as it's either a class name or an object reference, that's good enough.
+It doesn't even have to be a reference to a brand new object.
+
+You can have as many--or as few--constructors as you want, and you can
+name them whatever you care to. Blindly and obediently using new()
+for each and every constructor you ever write is to speak Perl with
+such a severe C++ accent that you do a disservice to both languages.
+There's no reason to insist that each class have but one constructor,
+or that a constructor be named new(), or that a constructor be
+used solely as a class method and not an object method.
+
+The next section shows how useful it can be to further distance ourselves
+from any formal distinction between class method calls and object method
+calls, both in constructors and in accessor methods.
+
+=head2 Translucent Attributes
+
+A package's eponymous hash can be used for more than just containing
+per-class, global state data. It can also serve as a sort of template
+containing default settings for object attributes. These default
+settings can then be used in constructors for initialization of a
+particular object. The class's eponymous hash can also be used to
+implement I<translucent attributes>. A translucent attribute is one
+that has a class-wide default. Each object can set its own value for the
+attribute, in which case C<< $object->attribute() >> returns that value.
+But if no value has been set, then C<< $object->attribute() >> returns
+the class-wide default.
+
+We'll apply something of a copy-on-write approach to these translucent
+attributes. If you're just fetching values from them, you get
+translucency. But if you store a new value to them, that new value is
+set on the current object. On the other hand, if you use the class as
+an object and store the attribute value directly on the class, then the
+meta-object's value changes, and later fetch operations on objects with
+uninitialized values for those attributes will retrieve the meta-object's
+new values. Objects with their own initialized values, however, won't
+see any change.
+
+Let's look at some concrete examples of using these properties before we
+show how to implement them. Suppose that a class named Some_Class
+had a translucent data attribute called "color". First you set the color
+in the meta-object, then you create three objects using a constructor
+that happens to be named &spawn.
+
+ use Vermin;
+ Vermin->color("vermilion");
+
+ $ob1 = Vermin->spawn(); # so that's where Jedi come from
+ $ob2 = Vermin->spawn();
+ $ob3 = Vermin->spawn();
+
+ print $obj3->color(); # prints "vermilion"
+
+Each of these objects' colors is now "vermilion", because that's the
+meta-object's value for that attribute, and these objects do not have
+individual color values set.
+
+Changing the attribute on one object has no effect on other objects
+previously created.
+
+ $ob3->color("chartreuse");
+ print $ob3->color(); # prints "chartreuse"
+ print $ob1->color(); # prints "vermilion", translucently
+
+If you now use $ob3 to spawn off another object, the new object will
+take the color its parent held, which now happens to be "chartreuse".
+That's because the constructor uses the invoking object as its template
+for initializing attributes. When that invoking object is the
+class name, the object used as a template is the eponymous meta-object.
+When the invoking object is a reference to an instantiated object, the
+&spawn constructor uses that existing object as a template.
+
+ $ob4 = $ob3->spawn(); # $ob3 now template, not %Vermin
+ print $ob4->color(); # prints "chartreuse"
+
+Any actual values set on the template object will be copied to the
+new object. But attributes undefined in the template object, being
+translucent, will remain undefined and consequently translucent in the
+new one as well.
+
+Now let's change the color attribute on the entire class:
+
+ Vermin->color("azure");
+ print $ob1->color(); # prints "azure"
+ print $ob2->color(); # prints "azure"
+ print $ob3->color(); # prints "chartreuse"
+ print $ob4->color(); # prints "chartreuse"
+
+That color change took effect only in the first pair of objects, which
+were still translucently accessing the meta-object's values. The second
+pair had per-object initialized colors, and so didn't change.
+
+One important question remains. Changes to the meta-object are reflected
+in translucent attributes in the entire class, but what about
+changes to discrete objects? If you change the color of $ob3, does the
+value of $ob4 see that change? Or vice-versa. If you change the color
+of $ob4, does then the value of $ob3 shift?
+
+ $ob3->color("amethyst");
+ print $ob3->color(); # prints "amethyst"
+ print $ob4->color(); # hmm: "chartreuse" or "amethyst"?
+
+While one could argue that in certain rare cases it should, let's not
+do that. Good taste aside, we want the answer to the question posed in
+the comment above to be "chartreuse", not "amethyst". So we'll treat
+these attributes similar to the way process attributes like environment
+variables, user and group IDs, or the current working directory are
+treated across a fork(). You can change only yourself, but you will see
+those changes reflected in your unspawned children. Changes to one object
+will propagate neither up to the parent nor down to any existing child objects.
+Those objects made later, however, will see the changes.
+
+If you have an object with an actual attribute value, and you want to
+make that object's attribute value translucent again, what do you do?
+Let's design the class so that when you invoke an accessor method with
+C<undef> as its argument, that attribute returns to translucency.
+
+ $ob4->color(undef); # back to "azure"
+
+Here's a complete implementation of Vermin as described above.
+
+ package Vermin;
+
+ # here's the class meta-object, eponymously named.
+ # it holds all class attributes, and also all instance attributes
+ # so the latter can be used for both initialization
+ # and translucency.
+
+ our %Vermin = ( # our() is new to perl5.6
+ PopCount => 0, # capital for class attributes
+ color => "beige", # small for instance attributes
+ );
+
+ # constructor method
+ # invoked as class method or object method
+ sub spawn {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ my $self = {};
+ bless($self, $class);
+ $class->{PopCount}++;
+ # init fields from invoking object, or omit if
+ # invoking object is the class to provide translucency
+ %$self = %$obclass if ref $obclass;
+ return $self;
+ }
+
+ # translucent accessor for "color" attribute
+ # invoked as class method or object method
+ sub color {
+ my $self = shift;
+ my $class = ref($self) || $self;
+
+ # handle class invocation
+ unless (ref $self) {
+ $class->{color} = shift if @_;
+ return $class->{color}
+ }
+
+ # handle object invocation
+ $self->{color} = shift if @_;
+ if (defined $self->{color}) { # not exists!
+ return $self->{color};
+ } else {
+ return $class->{color};
+ }
+ }
+
+ # accessor for "PopCount" class attribute
+ # invoked as class method or object method
+ # but uses object solely to locate meta-object
+ sub population {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ return $class->{PopCount};
+ }
+
+ # instance destructor
+ # invoked only as object method
+ sub DESTROY {
+ my $self = shift;
+ my $class = ref $self;
+ $class->{PopCount}--;
+ }
+
+Here are a couple of helper methods that might be convenient. They aren't
+accessor methods at all. They're used to detect accessibility of data
+attributes. The &is_translucent method determines whether a particular
+object attribute is coming from the meta-object. The &has_attribute
+method detects whether a class implements a particular property at all.
+It could also be used to distinguish undefined properties from non-existent
+ones.
+
+ # detect whether an object attribute is translucent
+ # (typically?) invoked only as object method
+ sub is_translucent {
+ my($self, $attr) = @_;
+ return !defined $self->{$attr};
+ }
+
+ # test for presence of attribute in class
+ # invoked as class method or object method
+ sub has_attribute {
+ my($self, $attr) = @_;
+ my $class = ref($self) || $self;
+ return exists $class->{$attr};
+ }
+
+If you prefer to install your accessors more generically, you can make
+use of the upper-case versus lower-case convention to register into the
+package appropriate methods cloned from generic closures.
+
+ for my $datum (keys %{ +__PACKAGE__ }) {
+ *$datum = ($datum =~ /^[A-Z]/)
+ ? sub { # install class accessor
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ return $class->{$datum};
+ }
+ : sub { # install translucent accessor
+ my $self = shift;
+ my $class = ref($self) || $self;
+ unless (ref $self) {
+ $class->{$datum} = shift if @_;
+ return $class->{$datum}
+ }
+ $self->{$datum} = shift if @_;
+ return defined $self->{$datum}
+ ? $self -> {$datum}
+ : $class -> {$datum}
+ }
+ }
+
+Translations of this closure-based approach into C++, Java, and Python
+have been left as exercises for the reader. Be sure to send us mail as
+soon as you're done.
+
+=head1 Class Data as Lexical Variables
+
+=head2 Privacy and Responsibility
+
+Unlike conventions used by some Perl programmers, in the previous
+examples, we didn't prefix the package variables used for class attributes
+with an underscore, nor did we do so for the names of the hash keys used
+for instance attributes. You don't need little markers on data names to
+suggest nominal privacy on attribute variables or hash keys, because these
+are B<already> notionally private! Outsiders have no business whatsoever
+playing with anything within a class save through the mediated access of
+its documented interface; in other words, through method invocations.
+And not even through just any method, either. Methods that begin with
+an underscore are traditionally considered off-limits outside the class.
+If outsiders skip the documented method interface to poke around the
+internals of your class and end up breaking something, that's not your
+fault--it's theirs.
+
+Perl believes in individual responsibility rather than mandated control.
+Perl respects you enough to let you choose your own preferred level of
+pain, or of pleasure. Perl believes that you are creative, intelligent,
+and capable of making your own decisions--and fully expects you to
+take complete responsibility for your own actions. In a perfect world,
+these admonitions alone would suffice, and everyone would be intelligent,
+responsible, happy, and creative. And careful. One probably shouldn't
+forget careful, and that's a good bit harder to expect. Even Einstein
+would take wrong turns by accident and end up lost in the wrong part
+of town.
+
+Some folks get the heebie-jeebies when they see package variables
+hanging out there for anyone to reach over and alter them. Some folks
+live in constant fear that someone somewhere might do something wicked.
+The solution to that problem is simply to fire the wicked, of course.
+But unfortunately, it's not as simple as all that. These cautious
+types are also afraid that they or others will do something not so
+much wicked as careless, whether by accident or out of desperation.
+If we fire everyone who ever gets careless, pretty soon there won't be
+anybody left to get any work done.
+
+Whether it's needless paranoia or sensible caution, this uneasiness can
+be a problem for some people. We can take the edge off their discomfort
+by providing the option of storing class attributes as lexical variables
+instead of as package variables. The my() operator is the source of
+all privacy in Perl, and it is a powerful form of privacy indeed.
+
+It is widely perceived, and indeed has often been written, that Perl
+provides no data hiding, that it affords the class designer no privacy
+nor isolation, merely a rag-tag assortment of weak and unenforceable
+social conventions instead. This perception is demonstrably false and
+easily disproven. In the next section, we show how to implement forms
+of privacy that are far stronger than those provided in nearly any
+other object-oriented language.
+
+=head2 File-Scoped Lexicals
+
+A lexical variable is visible only through the end of its static scope.
+That means that the only code able to access that variable is code
+residing textually below the my() operator through the end of its block
+if it has one, or through the end of the current file if it doesn't.
+
+Starting again with our simplest example given at the start of this
+document, we replace our() variables with my() versions.
+
+ package Some_Class;
+ my($CData1, $CData2); # file scope, not in any package
+ sub CData1 {
+ shift; # XXX: ignore calling class/object
+ $CData1 = shift if @_;
+ return $CData1;
+ }
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ $CData2 = shift if @_;
+ return $CData2;
+ }
+
+So much for that old $Some_Class::CData1 package variable and its brethren!
+Those are gone now, replaced with lexicals. No one outside the
+scope can reach in and alter the class state without resorting to the
+documented interface. Not even subclasses or superclasses of
+this one have unmediated access to $CData1. They have to invoke the &CData1
+method against Some_Class or an instance thereof, just like anybody else.
+
+To be scrupulously honest, that last statement assumes you haven't packed
+several classes together into the same file scope, nor strewn your class
+implementation across several different files. Accessibility of those
+variables is based uniquely on the static file scope. It has nothing to
+do with the package. That means that code in a different file but
+the same package (class) could not access those variables, yet code in the
+same file but a different package (class) could. There are sound reasons
+why we usually suggest a one-to-one mapping between files and packages
+and modules and classes. You don't have to stick to this suggestion if
+you really know what you're doing, but you're apt to confuse yourself
+otherwise, especially at first.
+
+If you'd like to aggregate your class attributes into one lexically scoped,
+composite structure, you're perfectly free to do so.
+
+ package Some_Class;
+ my %ClassData = (
+ CData1 => "",
+ CData2 => "",
+ );
+ sub CData1 {
+ shift; # XXX: ignore calling class/object
+ $ClassData{CData1} = shift if @_;
+ return $ClassData{CData1};
+ }
+ sub CData2 {
+ shift; # XXX: ignore calling class/object
+ $ClassData{CData2} = shift if @_;
+ return $ClassData{CData2};
+ }
+
+To make this more scalable as other class attributes are added, we can
+again register closures into the package symbol table to create accessor
+methods for them.
+
+ package Some_Class;
+ my %ClassData = (
+ CData1 => "",
+ CData2 => "",
+ );
+ for my $datum (keys %ClassData) {
+ no strict "refs";
+ *$datum = sub {
+ shift; # XXX: ignore calling class/object
+ $ClassData{$datum} = shift if @_;
+ return $ClassData{$datum};
+ };
+ }
+
+Requiring even your own class to use accessor methods like anybody else is
+probably a good thing. But demanding and expecting that everyone else,
+be they subclass or superclass, friend or foe, will all come to your
+object through mediation is more than just a good idea. It's absolutely
+critical to the model. Let there be in your mind no such thing as
+"public" data, nor even "protected" data, which is a seductive but
+ultimately destructive notion. Both will come back to bite at you.
+That's because as soon as you take that first step out of the solid
+position in which all state is considered completely private, save from the
+perspective of its own accessor methods, you have violated the envelope.
+And, having pierced that encapsulating envelope, you shall doubtless
+someday pay the price when future changes in the implementation break
+unrelated code. Considering that avoiding this infelicitous outcome was
+precisely why you consented to suffer the slings and arrows of obsequious
+abstraction by turning to object orientation in the first place, such
+breakage seems unfortunate in the extreme.
+
+=head2 More Inheritance Concerns
+
+Suppose that Some_Class were used as a base class from which to derive
+Another_Class. If you invoke a &CData method on the derived class or
+on an object of that class, what do you get? Would the derived class
+have its own state, or would it piggyback on its base class's versions
+of the class attributes?
+
+The answer is that under the scheme outlined above, the derived class
+would B<not> have its own state data. As before, whether you consider
+this a good thing or a bad one depends on the semantics of the classes
+involved.
+
+The cleanest, sanest, simplest way to address per-class state in a
+lexical is for the derived class to override its base class's version
+of the method that accesses the class attributes. Since the actual method
+called is the one in the object's derived class if this exists, you
+automatically get per-class state this way. Any urge to provide an
+unadvertised method to sneak out a reference to the %ClassData hash
+should be strenuously resisted.
+
+As with any other overridden method, the implementation in the
+derived class always has the option of invoking its base class's
+version of the method in addition to its own. Here's an example:
+
+ package Another_Class;
+ @ISA = qw(Some_Class);
+
+ my %ClassData = (
+ CData1 => "",
+ );
+
+ sub CData1 {
+ my($self, $newvalue) = @_;
+ if (@_ > 1) {
+ # set locally first
+ $ClassData{CData1} = $newvalue;
+
+ # then pass the buck up to the first
+ # overridden version, if there is one
+ if ($self->can("SUPER::CData1")) {
+ $self->SUPER::CData1($newvalue);
+ }
+ }
+ return $ClassData{CData1};
+ }
+
+Those dabbling in multiple inheritance might be concerned
+about there being more than one override.
+
+ for my $parent (@ISA) {
+ my $methname = $parent . "::CData1";
+ if ($self->can($methname)) {
+ $self->$methname($newvalue);
+ }
+ }
+
+Because the &UNIVERSAL::can method returns a reference
+to the function directly, you can use this directly
+for a significant performance improvement:
+
+ for my $parent (@ISA) {
+ if (my $coderef = $self->can($parent . "::CData1")) {
+ $self->$coderef($newvalue);
+ }
+ }
+
+If you override C<UNIVERSAL::can> in your own classes, be sure to return the
+reference appropriately.
+
+=head2 Locking the Door and Throwing Away the Key
+
+As currently implemented, any code within the same scope as the
+file-scoped lexical %ClassData can alter that hash directly. Is that
+ok? Is it acceptable or even desirable to allow other parts of the
+implementation of this class to access class attributes directly?
+
+That depends on how careful you want to be. Think back to the Cosmos
+class. If the &supernova method had directly altered $Cosmos::Stars or
+C<$Cosmos::Cosmos{stars}>, then we wouldn't have been able to reuse the
+class when it came to inventing a Multiverse. So letting even the class
+itself access its own class attributes without the mediating intervention of
+properly designed accessor methods is probably not a good idea after all.
+
+Restricting access to class attributes from the class itself is usually
+not enforceable even in strongly object-oriented languages. But in Perl,
+you can.
+
+Here's one way:
+
+ package Some_Class;
+
+ { # scope for hiding $CData1
+ my $CData1;
+ sub CData1 {
+ shift; # XXX: unused
+ $CData1 = shift if @_;
+ return $CData1;
+ }
+ }
+
+ { # scope for hiding $CData2
+ my $CData2;
+ sub CData2 {
+ shift; # XXX: unused
+ $CData2 = shift if @_;
+ return $CData2;
+ }
+ }
+
+No one--absolutely no one--is allowed to read or write the class
+attributes without the mediation of the managing accessor method, since
+only that method has access to the lexical variable it's managing.
+This use of mediated access to class attributes is a form of privacy far
+stronger than most OO languages provide.
+
+The repetition of code used to create per-datum accessor methods chafes
+at our Laziness, so we'll again use closures to create similar
+methods.
+
+ package Some_Class;
+
+ { # scope for ultra-private meta-object for class attributes
+ my %ClassData = (
+ CData1 => "",
+ CData2 => "",
+ );
+
+ for my $datum (keys %ClassData ) {
+ no strict "refs";
+ *$datum = sub {
+ use strict "refs";
+ my ($self, $newvalue) = @_;
+ $ClassData{$datum} = $newvalue if @_ > 1;
+ return $ClassData{$datum};
+ }
+ }
+
+ }
+
+The closure above can be modified to take inheritance into account using
+the &UNIVERSAL::can method and SUPER as shown previously.
+
+=head2 Translucency Revisited
+
+The Vermin class demonstrates translucency using a package variable,
+eponymously named %Vermin, as its meta-object. If you prefer to
+use absolutely no package variables beyond those necessary to appease
+inheritance or possibly the Exporter, this strategy is closed to you.
+That's too bad, because translucent attributes are an appealing
+technique, so it would be valuable to devise an implementation using
+only lexicals.
+
+There's a second reason why you might wish to avoid the eponymous
+package hash. If you use class names with double-colons in them, you
+would end up poking around somewhere you might not have meant to poke.
+
+ package Vermin;
+ $class = "Vermin";
+ $class->{PopCount}++;
+ # accesses $Vermin::Vermin{PopCount}
+
+ package Vermin::Noxious;
+ $class = "Vermin::Noxious";
+ $class->{PopCount}++;
+ # accesses $Vermin::Noxious{PopCount}
+
+In the first case, because the class name had no double-colons, we got
+the hash in the current package. But in the second case, instead of
+getting some hash in the current package, we got the hash %Noxious in
+the Vermin package. (The noxious vermin just invaded another package and
+sprayed their data around it. :-) Perl doesn't support relative packages
+in its naming conventions, so any double-colons trigger a fully-qualified
+lookup instead of just looking in the current package.
+
+In practice, it is unlikely that the Vermin class had an existing
+package variable named %Noxious that you just blew away. If you're
+still mistrustful, you could always stake out your own territory
+where you know the rules, such as using Eponymous::Vermin::Noxious or
+Hieronymus::Vermin::Boschious or Leave_Me_Alone::Vermin::Noxious as class
+names instead. Sure, it's in theory possible that someone else has
+a class named Eponymous::Vermin with its own %Noxious hash, but this
+kind of thing is always true. There's no arbiter of package names.
+It's always the case that globals like @Cwd::ISA would collide if more
+than one class uses the same Cwd package.
+
+If this still leaves you with an uncomfortable twinge of paranoia,
+we have another solution for you. There's nothing that says that you
+have to have a package variable to hold a class meta-object, either for
+monadic classes or for translucent attributes. Just code up the methods
+so that they access a lexical instead.
+
+Here's another implementation of the Vermin class with semantics identical
+to those given previously, but this time using no package variables.
+
+ package Vermin;
+
+
+ # Here's the class meta-object, eponymously named.
+ # It holds all class data, and also all instance data
+ # so the latter can be used for both initialization
+ # and translucency. it's a template.
+ my %ClassData = (
+ PopCount => 0, # capital for class attributes
+ color => "beige", # small for instance attributes
+ );
+
+ # constructor method
+ # invoked as class method or object method
+ sub spawn {
+ my $obclass = shift;
+ my $class = ref($obclass) || $obclass;
+ my $self = {};
+ bless($self, $class);
+ $ClassData{PopCount}++;
+ # init fields from invoking object, or omit if
+ # invoking object is the class to provide translucency
+ %$self = %$obclass if ref $obclass;
+ return $self;
+ }
+
+ # translucent accessor for "color" attribute
+ # invoked as class method or object method
+ sub color {
+ my $self = shift;
+
+ # handle class invocation
+ unless (ref $self) {
+ $ClassData{color} = shift if @_;
+ return $ClassData{color}
+ }
+
+ # handle object invocation
+ $self->{color} = shift if @_;
+ if (defined $self->{color}) { # not exists!
+ return $self->{color};
+ } else {
+ return $ClassData{color};
+ }
+ }
+
+ # class attribute accessor for "PopCount" attribute
+ # invoked as class method or object method
+ sub population {
+ return $ClassData{PopCount};
+ }
+
+ # instance destructor; invoked only as object method
+ sub DESTROY {
+ $ClassData{PopCount}--;
+ }
+
+ # detect whether an object attribute is translucent
+ # (typically?) invoked only as object method
+ sub is_translucent {
+ my($self, $attr) = @_;
+ $self = \%ClassData if !ref $self;
+ return !defined $self->{$attr};
+ }
+
+ # test for presence of attribute in class
+ # invoked as class method or object method
+ sub has_attribute {
+ my($self, $attr) = @_;
+ return exists $ClassData{$attr};
+ }
+
+=head1 NOTES
+
+Inheritance is a powerful but subtle device, best used only after careful
+forethought and design. Aggregation instead of inheritance is often a
+better approach.
+
+You can't use file-scoped lexicals in conjunction with the SelfLoader
+or the AutoLoader, because they alter the lexical scope in which the
+module's methods wind up getting compiled.
+
+The usual mealy-mouthed package-munging doubtless applies to setting
+up names of object attributes. For example, C<< $self->{ObData1} >>
+should probably be C<< $self->{ __PACKAGE__ . "_ObData1" } >>, but that
+would just confuse the examples.
+
+=head1 SEE ALSO
+
+L<perltoot>, L<perlobj>, L<perlmod>, and L<perlbot>.
+
+The Tie::SecureHash and Class::Data::Inheritable modules from CPAN are
+worth checking out.
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1999 Tom Christiansen.
+All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
+
+=head1 ACKNOWLEDGEMENTS
+
+Russ Allbery, Jon Orwant, Randy Ray, Larry Rosler, Nat Torkington,
+and Stephen Warren all contributed suggestions and corrections to this
+piece. Thanks especially to Damian Conway for his ideas and feedback,
+and without whose indirect prodding I might never have taken the time
+to show others how much Perl has to offer in the way of objects once
+you start thinking outside the tiny little box that today's "popular"
+object-oriented languages enforce.
+
+=head1 HISTORY
+
+Last edit: Sun Feb 4 20:50:28 EST 2001
diff --git a/Master/tlpkg/tlperl/lib/pods/perltoot.pod b/Master/tlpkg/tlperl/lib/pods/perltoot.pod
new file mode 100644
index 00000000000..0d8648bdd55
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltoot.pod
@@ -0,0 +1,1836 @@
+=head1 NAME
+
+perltoot - Tom's object-oriented tutorial for perl
+
+=head1 DESCRIPTION
+
+Object-oriented programming is a big seller these days. Some managers
+would rather have objects than sliced bread. Why is that? What's so
+special about an object? Just what I<is> an object anyway?
+
+An object is nothing but a way of tucking away complex behaviours into
+a neat little easy-to-use bundle. (This is what professors call
+abstraction.) Smart people who have nothing to do but sit around for
+weeks on end figuring out really hard problems make these nifty
+objects that even regular people can use. (This is what professors call
+software reuse.) Users (well, programmers) can play with this little
+bundle all they want, but they aren't to open it up and mess with the
+insides. Just like an expensive piece of hardware, the contract says
+that you void the warranty if you muck with the cover. So don't do that.
+
+The heart of objects is the class, a protected little private namespace
+full of data and functions. A class is a set of related routines that
+addresses some problem area. You can think of it as a user-defined type.
+The Perl package mechanism, also used for more traditional modules,
+is used for class modules as well. Objects "live" in a class, meaning
+that they belong to some package.
+
+More often than not, the class provides the user with little bundles.
+These bundles are objects. They know whose class they belong to,
+and how to behave. Users ask the class to do something, like "give
+me an object." Or they can ask one of these objects to do something.
+Asking a class to do something for you is calling a I<class method>.
+Asking an object to do something for you is calling an I<object method>.
+Asking either a class (usually) or an object (sometimes) to give you
+back an object is calling a I<constructor>, which is just a
+kind of method.
+
+That's all well and good, but how is an object different from any other
+Perl data type? Just what is an object I<really>; that is, what's its
+fundamental type? The answer to the first question is easy. An object
+is different from any other data type in Perl in one and only one way:
+you may dereference it using not merely string or numeric subscripts
+as with simple arrays and hashes, but with named subroutine calls.
+In a word, with I<methods>.
+
+The answer to the second question is that it's a reference, and not just
+any reference, mind you, but one whose referent has been I<bless>()ed
+into a particular class (read: package). What kind of reference? Well,
+the answer to that one is a bit less concrete. That's because in Perl
+the designer of the class can employ any sort of reference they'd like
+as the underlying intrinsic data type. It could be a scalar, an array,
+or a hash reference. It could even be a code reference. But because
+of its inherent flexibility, an object is usually a hash reference.
+
+=head1 Creating a Class
+
+Before you create a class, you need to decide what to name it. That's
+because the class (package) name governs the name of the file used to
+house it, just as with regular modules. Then, that class (package)
+should provide one or more ways to generate objects. Finally, it should
+provide mechanisms to allow users of its objects to indirectly manipulate
+these objects from a distance.
+
+For example, let's make a simple Person class module. It gets stored in
+the file Person.pm. If it were called a Happy::Person class, it would
+be stored in the file Happy/Person.pm, and its package would become
+Happy::Person instead of just Person. (On a personal computer not
+running Unix or Plan 9, but something like Mac OS or VMS, the directory
+separator may be different, but the principle is the same.) Do not assume
+any formal relationship between modules based on their directory names.
+This is merely a grouping convenience, and has no effect on inheritance,
+variable accessibility, or anything else.
+
+For this module we aren't going to use Exporter, because we're
+a well-behaved class module that doesn't export anything at all.
+In order to manufacture objects, a class needs to have a I<constructor
+method>. A constructor gives you back not just a regular data type,
+but a brand-new object in that class. This magic is taken care of by
+the bless() function, whose sole purpose is to enable its referent to
+be used as an object. Remember: being an object really means nothing
+more than that methods may now be called against it.
+
+While a constructor may be named anything you'd like, most Perl
+programmers seem to like to call theirs new(). However, new() is not
+a reserved word, and a class is under no obligation to supply such.
+Some programmers have also been known to use a function with
+the same name as the class as the constructor.
+
+=head2 Object Representation
+
+By far the most common mechanism used in Perl to represent a Pascal
+record, a C struct, or a C++ class is an anonymous hash. That's because a
+hash has an arbitrary number of data fields, each conveniently accessed by
+an arbitrary name of your own devising.
+
+If you were just doing a simple
+struct-like emulation, you would likely go about it something like this:
+
+ $rec = {
+ name => "Jason",
+ age => 23,
+ peers => [ "Norbert", "Rhys", "Phineas"],
+ };
+
+If you felt like it, you could add a bit of visual distinction
+by up-casing the hash keys:
+
+ $rec = {
+ NAME => "Jason",
+ AGE => 23,
+ PEERS => [ "Norbert", "Rhys", "Phineas"],
+ };
+
+And so you could get at C<< $rec->{NAME} >> to find "Jason", or
+C<< @{ $rec->{PEERS} } >> to get at "Norbert", "Rhys", and "Phineas".
+(Have you ever noticed how many 23-year-old programmers seem to
+be named "Jason" these days? :-)
+
+This same model is often used for classes, although it is not considered
+the pinnacle of programming propriety for folks from outside the
+class to come waltzing into an object, brazenly accessing its data
+members directly. Generally speaking, an object should be considered
+an opaque cookie that you use I<object methods> to access. Visually,
+methods look like you're dereffing a reference using a function name
+instead of brackets or braces.
+
+=head2 Class Interface
+
+Some languages provide a formal syntactic interface to a class's methods,
+but Perl does not. It relies on you to read the documentation of each
+class. If you try to call an undefined method on an object, Perl won't
+complain, but the program will trigger an exception while it's running.
+Likewise, if you call a method expecting a prime number as its argument
+with a non-prime one instead, you can't expect the compiler to catch this.
+(Well, you can expect it all you like, but it's not going to happen.)
+
+Let's suppose you have a well-educated user of your Person class,
+someone who has read the docs that explain the prescribed
+interface. Here's how they might use the Person class:
+
+ use Person;
+
+ $him = Person->new();
+ $him->name("Jason");
+ $him->age(23);
+ $him->peers( "Norbert", "Rhys", "Phineas" );
+
+ push @All_Recs, $him; # save object in array for later
+
+ printf "%s is %d years old.\n", $him->name, $him->age;
+ print "His peers are: ", join(", ", $him->peers), "\n";
+
+ printf "Last rec's name is %s\n", $All_Recs[-1]->name;
+
+As you can see, the user of the class doesn't know (or at least, has no
+business paying attention to the fact) that the object has one particular
+implementation or another. The interface to the class and its objects
+is exclusively via methods, and that's all the user of the class should
+ever play with.
+
+=head2 Constructors and Instance Methods
+
+Still, I<someone> has to know what's in the object. And that someone is
+the class. It implements methods that the programmer uses to access
+the object. Here's how to implement the Person class using the standard
+hash-ref-as-an-object idiom. We'll make a class method called new() to
+act as the constructor, and three object methods called name(), age(), and
+peers() to get at per-object data hidden away in our anonymous hash.
+
+ package Person;
+ use strict;
+
+ ##################################################
+ ## the object constructor (simplistic version) ##
+ ##################################################
+ sub new {
+ my $self = {};
+ $self->{NAME} = undef;
+ $self->{AGE} = undef;
+ $self->{PEERS} = [];
+ bless($self); # but see below
+ return $self;
+ }
+
+ ##############################################
+ ## methods to access per-object data ##
+ ## ##
+ ## With args, they set the value. Without ##
+ ## any, they only retrieve it/them. ##
+ ##############################################
+
+ sub name {
+ my $self = shift;
+ if (@_) { $self->{NAME} = shift }
+ return $self->{NAME};
+ }
+
+ sub age {
+ my $self = shift;
+ if (@_) { $self->{AGE} = shift }
+ return $self->{AGE};
+ }
+
+ sub peers {
+ my $self = shift;
+ if (@_) { @{ $self->{PEERS} } = @_ }
+ return @{ $self->{PEERS} };
+ }
+
+ 1; # so the require or use succeeds
+
+We've created three methods to access an object's data, name(), age(),
+and peers(). These are all substantially similar. If called with an
+argument, they set the appropriate field; otherwise they return the
+value held by that field, meaning the value of that hash key.
+
+=head2 Planning for the Future: Better Constructors
+
+Even though at this point you may not even know what it means, someday
+you're going to worry about inheritance. (You can safely ignore this
+for now and worry about it later if you'd like.) To ensure that this
+all works out smoothly, you must use the double-argument form of bless().
+The second argument is the class into which the referent will be blessed.
+By not assuming our own class as the default second argument and instead
+using the class passed into us, we make our constructor inheritable.
+
+ sub new {
+ my $class = shift;
+ my $self = {};
+ $self->{NAME} = undef;
+ $self->{AGE} = undef;
+ $self->{PEERS} = [];
+ bless ($self, $class);
+ return $self;
+ }
+
+That's about all there is for constructors. These methods bring objects
+to life, returning neat little opaque bundles to the user to be used in
+subsequent method calls.
+
+=head2 Destructors
+
+Every story has a beginning and an end. The beginning of the object's
+story is its constructor, explicitly called when the object comes into
+existence. But the ending of its story is the I<destructor>, a method
+implicitly called when an object leaves this life. Any per-object
+clean-up code is placed in the destructor, which must (in Perl) be called
+DESTROY.
+
+If constructors can have arbitrary names, then why not destructors?
+Because while a constructor is explicitly called, a destructor is not.
+Destruction happens automatically via Perl's garbage collection (GC)
+system, which is a quick but somewhat lazy reference-based GC system.
+To know what to call, Perl insists that the destructor be named DESTROY.
+Perl's notion of the right time to call a destructor is not well-defined
+currently, which is why your destructors should not rely on when they are
+called.
+
+Why is DESTROY in all caps? Perl on occasion uses purely uppercase
+function names as a convention to indicate that the function will
+be automatically called by Perl in some way. Others that are called
+implicitly include BEGIN, END, AUTOLOAD, plus all methods used by
+tied objects, described in L<perltie>.
+
+In really good object-oriented programming languages, the user doesn't
+care when the destructor is called. It just happens when it's supposed
+to. In low-level languages without any GC at all, there's no way to
+depend on this happening at the right time, so the programmer must
+explicitly call the destructor to clean up memory and state, crossing
+their fingers that it's the right time to do so. Unlike C++, an
+object destructor is nearly never needed in Perl, and even when it is,
+explicit invocation is uncalled for. In the case of our Person class,
+we don't need a destructor because Perl takes care of simple matters
+like memory deallocation.
+
+The only situation where Perl's reference-based GC won't work is
+when there's a circularity in the data structure, such as:
+
+ $this->{WHATEVER} = $this;
+
+In that case, you must delete the self-reference manually if you expect
+your program not to leak memory. While admittedly error-prone, this is
+the best we can do right now. Nonetheless, rest assured that when your
+program is finished, its objects' destructors are all duly called.
+So you are guaranteed that an object I<eventually> gets properly
+destroyed, except in the unique case of a program that never exits.
+(If you're running Perl embedded in another application, this full GC
+pass happens a bit more frequently--whenever a thread shuts down.)
+
+=head2 Other Object Methods
+
+The methods we've talked about so far have either been constructors or
+else simple "data methods", interfaces to data stored in the object.
+These are a bit like an object's data members in the C++ world, except
+that strangers don't access them as data. Instead, they should only
+access the object's data indirectly via its methods. This is an
+important rule: in Perl, access to an object's data should I<only>
+be made through methods.
+
+Perl doesn't impose restrictions on who gets to use which methods.
+The public-versus-private distinction is by convention, not syntax.
+(Well, unless you use the Alias module described below in
+L<Data Members as Variables>.) Occasionally you'll see method names beginning or ending
+with an underscore or two. This marking is a convention indicating
+that the methods are private to that class alone and sometimes to its
+closest acquaintances, its immediate subclasses. But this distinction
+is not enforced by Perl itself. It's up to the programmer to behave.
+
+There's no reason to limit methods to those that simply access data.
+Methods can do anything at all. The key point is that they're invoked
+against an object or a class. Let's say we'd like object methods that
+do more than fetch or set one particular field.
+
+ sub exclaim {
+ my $self = shift;
+ return sprintf "Hi, I'm %s, age %d, working with %s",
+ $self->{NAME}, $self->{AGE}, join(", ", @{$self->{PEERS}});
+ }
+
+Or maybe even one like this:
+
+ sub happy_birthday {
+ my $self = shift;
+ return ++$self->{AGE};
+ }
+
+Some might argue that one should go at these this way:
+
+ sub exclaim {
+ my $self = shift;
+ return sprintf "Hi, I'm %s, age %d, working with %s",
+ $self->name, $self->age, join(", ", $self->peers);
+ }
+
+ sub happy_birthday {
+ my $self = shift;
+ return $self->age( $self->age() + 1 );
+ }
+
+But since these methods are all executing in the class itself, this
+may not be critical. There are tradeoffs to be made. Using direct
+hash access is faster (about an order of magnitude faster, in fact), and
+it's more convenient when you want to interpolate in strings. But using
+methods (the external interface) internally shields not just the users of
+your class but even you yourself from changes in your data representation.
+
+=head1 Class Data
+
+What about "class data", data items common to each object in a class?
+What would you want that for? Well, in your Person class, you might
+like to keep track of the total people alive. How do you implement that?
+
+You I<could> make it a global variable called $Person::Census. But about
+only reason you'd do that would be if you I<wanted> people to be able to
+get at your class data directly. They could just say $Person::Census
+and play around with it. Maybe this is ok in your design scheme.
+You might even conceivably want to make it an exported variable. To be
+exportable, a variable must be a (package) global. If this were a
+traditional module rather than an object-oriented one, you might do that.
+
+While this approach is expected in most traditional modules, it's
+generally considered rather poor form in most object modules. In an
+object module, you should set up a protective veil to separate interface
+from implementation. So provide a class method to access class data
+just as you provide object methods to access object data.
+
+So, you I<could> still keep $Census as a package global and rely upon
+others to honor the contract of the module and therefore not play around
+with its implementation. You could even be supertricky and make $Census a
+tied object as described in L<perltie>, thereby intercepting all accesses.
+
+But more often than not, you just want to make your class data a
+file-scoped lexical. To do so, simply put this at the top of the file:
+
+ my $Census = 0;
+
+Even though the scope of a my() normally expires when the block in which
+it was declared is done (in this case the whole file being required or
+used), Perl's deep binding of lexical variables guarantees that the
+variable will not be deallocated, remaining accessible to functions
+declared within that scope. This doesn't work with global variables
+given temporary values via local(), though.
+
+Irrespective of whether you leave $Census a package global or make
+it instead a file-scoped lexical, you should make these
+changes to your Person::new() constructor:
+
+ sub new {
+ my $class = shift;
+ my $self = {};
+ $Census++;
+ $self->{NAME} = undef;
+ $self->{AGE} = undef;
+ $self->{PEERS} = [];
+ bless ($self, $class);
+ return $self;
+ }
+
+ sub population {
+ return $Census;
+ }
+
+Now that we've done this, we certainly do need a destructor so that
+when Person is destroyed, the $Census goes down. Here's how
+this could be done:
+
+ sub DESTROY { --$Census }
+
+Notice how there's no memory to deallocate in the destructor? That's
+something that Perl takes care of for you all by itself.
+
+Alternatively, you could use the Class::Data::Inheritable module from
+CPAN.
+
+
+=head2 Accessing Class Data
+
+It turns out that this is not really a good way to go about handling
+class data. A good scalable rule is that I<you must never reference class
+data directly from an object method>. Otherwise you aren't building a
+scalable, inheritable class. The object must be the rendezvous point
+for all operations, especially from an object method. The globals
+(class data) would in some sense be in the "wrong" package in your
+derived classes. In Perl, methods execute in the context of the class
+they were defined in, I<not> that of the object that triggered them.
+Therefore, namespace visibility of package globals in methods is unrelated
+to inheritance.
+
+Got that? Maybe not. Ok, let's say that some other class "borrowed"
+(well, inherited) the DESTROY method as it was defined above. When those
+objects are destroyed, the original $Census variable will be altered,
+not the one in the new class's package namespace. Perhaps this is what
+you want, but probably it isn't.
+
+Here's how to fix this. We'll store a reference to the data in the
+value accessed by the hash key "_CENSUS". Why the underscore? Well,
+mostly because an initial underscore already conveys strong feelings
+of magicalness to a C programmer. It's really just a mnemonic device
+to remind ourselves that this field is special and not to be used as
+a public data member in the same way that NAME, AGE, and PEERS are.
+(Because we've been developing this code under the strict pragma, prior
+to perl version 5.004 we'll have to quote the field name.)
+
+ sub new {
+ my $class = shift;
+ my $self = {};
+ $self->{NAME} = undef;
+ $self->{AGE} = undef;
+ $self->{PEERS} = [];
+ # "private" data
+ $self->{"_CENSUS"} = \$Census;
+ bless ($self, $class);
+ ++ ${ $self->{"_CENSUS"} };
+ return $self;
+ }
+
+ sub population {
+ my $self = shift;
+ if (ref $self) {
+ return ${ $self->{"_CENSUS"} };
+ } else {
+ return $Census;
+ }
+ }
+
+ sub DESTROY {
+ my $self = shift;
+ -- ${ $self->{"_CENSUS"} };
+ }
+
+=head2 Debugging Methods
+
+It's common for a class to have a debugging mechanism. For example,
+you might want to see when objects are created or destroyed. To do that,
+add a debugging variable as a file-scoped lexical. For this, we'll pull
+in the standard Carp module to emit our warnings and fatal messages.
+That way messages will come out with the caller's filename and
+line number instead of our own; if we wanted them to be from our own
+perspective, we'd just use die() and warn() directly instead of croak()
+and carp() respectively.
+
+ use Carp;
+ my $Debugging = 0;
+
+Now add a new class method to access the variable.
+
+ sub debug {
+ my $class = shift;
+ if (ref $class) { confess "Class method called as object method" }
+ unless (@_ == 1) { confess "usage: CLASSNAME->debug(level)" }
+ $Debugging = shift;
+ }
+
+Now fix up DESTROY to murmur a bit as the moribund object expires:
+
+ sub DESTROY {
+ my $self = shift;
+ if ($Debugging) { carp "Destroying $self " . $self->name }
+ -- ${ $self->{"_CENSUS"} };
+ }
+
+One could conceivably make a per-object debug state. That
+way you could call both of these:
+
+ Person->debug(1); # entire class
+ $him->debug(1); # just this object
+
+To do so, we need our debugging method to be a "bimodal" one, one that
+works on both classes I<and> objects. Therefore, adjust the debug()
+and DESTROY methods as follows:
+
+ sub debug {
+ my $self = shift;
+ confess "usage: thing->debug(level)" unless @_ == 1;
+ my $level = shift;
+ if (ref($self)) {
+ $self->{"_DEBUG"} = $level; # just myself
+ } else {
+ $Debugging = $level; # whole class
+ }
+ }
+
+ sub DESTROY {
+ my $self = shift;
+ if ($Debugging || $self->{"_DEBUG"}) {
+ carp "Destroying $self " . $self->name;
+ }
+ -- ${ $self->{"_CENSUS"} };
+ }
+
+What happens if a derived class (which we'll call Employee) inherits
+methods from this Person base class? Then C<< Employee->debug() >>, when called
+as a class method, manipulates $Person::Debugging not $Employee::Debugging.
+
+=head2 Class Destructors
+
+The object destructor handles the death of each distinct object. But sometimes
+you want a bit of cleanup when the entire class is shut down, which
+currently only happens when the program exits. To make such a
+I<class destructor>, create a function in that class's package named
+END. This works just like the END function in traditional modules,
+meaning that it gets called whenever your program exits unless it execs
+or dies of an uncaught signal. For example,
+
+ sub END {
+ if ($Debugging) {
+ print "All persons are going away now.\n";
+ }
+ }
+
+When the program exits, all the class destructors (END functions) are
+be called in the opposite order that they were loaded in (LIFO order).
+
+=head2 Documenting the Interface
+
+And there you have it: we've just shown you the I<implementation> of this
+Person class. Its I<interface> would be its documentation. Usually this
+means putting it in pod ("plain old documentation") format right there
+in the same file. In our Person example, we would place the following
+docs anywhere in the Person.pm file. Even though it looks mostly like
+code, it's not. It's embedded documentation such as would be used by
+the pod2man, pod2html, or pod2text programs. The Perl compiler ignores
+pods entirely, just as the translators ignore code. Here's an example of
+some pods describing the informal interface:
+
+ =head1 NAME
+
+ Person - class to implement people
+
+ =head1 SYNOPSIS
+
+ use Person;
+
+ #################
+ # class methods #
+ #################
+ $ob = Person->new;
+ $count = Person->population;
+
+ #######################
+ # object data methods #
+ #######################
+
+ ### get versions ###
+ $who = $ob->name;
+ $years = $ob->age;
+ @pals = $ob->peers;
+
+ ### set versions ###
+ $ob->name("Jason");
+ $ob->age(23);
+ $ob->peers( "Norbert", "Rhys", "Phineas" );
+
+ ########################
+ # other object methods #
+ ########################
+
+ $phrase = $ob->exclaim;
+ $ob->happy_birthday;
+
+ =head1 DESCRIPTION
+
+ The Person class implements dah dee dah dee dah....
+
+That's all there is to the matter of interface versus implementation.
+A programmer who opens up the module and plays around with all the private
+little shiny bits that were safely locked up behind the interface contract
+has voided the warranty, and you shouldn't worry about their fate.
+
+=head1 Aggregation
+
+Suppose you later want to change the class to implement better names.
+Perhaps you'd like to support both given names (called Christian names,
+irrespective of one's religion) and family names (called surnames), plus
+nicknames and titles. If users of your Person class have been properly
+accessing it through its documented interface, then you can easily change
+the underlying implementation. If they haven't, then they lose and
+it's their fault for breaking the contract and voiding their warranty.
+
+To do this, we'll make another class, this one called Fullname. What's
+the Fullname class look like? To answer that question, you have to
+first figure out how you want to use it. How about we use it this way:
+
+ $him = Person->new();
+ $him->fullname->title("St");
+ $him->fullname->christian("Thomas");
+ $him->fullname->surname("Aquinas");
+ $him->fullname->nickname("Tommy");
+ printf "His normal name is %s\n", $him->name;
+ printf "But his real name is %s\n", $him->fullname->as_string;
+
+Ok. To do this, we'll change Person::new() so that it supports
+a full name field this way:
+
+ sub new {
+ my $class = shift;
+ my $self = {};
+ $self->{FULLNAME} = Fullname->new();
+ $self->{AGE} = undef;
+ $self->{PEERS} = [];
+ $self->{"_CENSUS"} = \$Census;
+ bless ($self, $class);
+ ++ ${ $self->{"_CENSUS"} };
+ return $self;
+ }
+
+ sub fullname {
+ my $self = shift;
+ return $self->{FULLNAME};
+ }
+
+Then to support old code, define Person::name() this way:
+
+ sub name {
+ my $self = shift;
+ return $self->{FULLNAME}->nickname(@_)
+ || $self->{FULLNAME}->christian(@_);
+ }
+
+Here's the Fullname class. We'll use the same technique
+of using a hash reference to hold data fields, and methods
+by the appropriate name to access them:
+
+ package Fullname;
+ use strict;
+
+ sub new {
+ my $class = shift;
+ my $self = {
+ TITLE => undef,
+ CHRISTIAN => undef,
+ SURNAME => undef,
+ NICK => undef,
+ };
+ bless ($self, $class);
+ return $self;
+ }
+
+ sub christian {
+ my $self = shift;
+ if (@_) { $self->{CHRISTIAN} = shift }
+ return $self->{CHRISTIAN};
+ }
+
+ sub surname {
+ my $self = shift;
+ if (@_) { $self->{SURNAME} = shift }
+ return $self->{SURNAME};
+ }
+
+ sub nickname {
+ my $self = shift;
+ if (@_) { $self->{NICK} = shift }
+ return $self->{NICK};
+ }
+
+ sub title {
+ my $self = shift;
+ if (@_) { $self->{TITLE} = shift }
+ return $self->{TITLE};
+ }
+
+ sub as_string {
+ my $self = shift;
+ my $name = join(" ", @$self{'CHRISTIAN', 'SURNAME'});
+ if ($self->{TITLE}) {
+ $name = $self->{TITLE} . " " . $name;
+ }
+ return $name;
+ }
+
+ 1;
+
+Finally, here's the test program:
+
+ #!/usr/bin/perl -w
+ use strict;
+ use Person;
+ sub END { show_census() }
+
+ sub show_census () {
+ printf "Current population: %d\n", Person->population;
+ }
+
+ Person->debug(1);
+
+ show_census();
+
+ my $him = Person->new();
+
+ $him->fullname->christian("Thomas");
+ $him->fullname->surname("Aquinas");
+ $him->fullname->nickname("Tommy");
+ $him->fullname->title("St");
+ $him->age(1);
+
+ printf "%s is really %s.\n", $him->name, $him->fullname->as_string;
+ printf "%s's age: %d.\n", $him->name, $him->age;
+ $him->happy_birthday;
+ printf "%s's age: %d.\n", $him->name, $him->age;
+
+ show_census();
+
+=head1 Inheritance
+
+Object-oriented programming systems all support some notion of
+inheritance. Inheritance means allowing one class to piggy-back on
+top of another one so you don't have to write the same code again and
+again. It's about software reuse, and therefore related to Laziness,
+the principal virtue of a programmer. (The import/export mechanisms in
+traditional modules are also a form of code reuse, but a simpler one than
+the true inheritance that you find in object modules.)
+
+Sometimes the syntax of inheritance is built into the core of the
+language, and sometimes it's not. Perl has no special syntax for
+specifying the class (or classes) to inherit from. Instead, it's all
+strictly in the semantics. Each package can have a variable called @ISA,
+which governs (method) inheritance. If you try to call a method on an
+object or class, and that method is not found in that object's package,
+Perl then looks to @ISA for other packages to go looking through in
+search of the missing method.
+
+Like the special per-package variables recognized by Exporter (such as
+@EXPORT, @EXPORT_OK, @EXPORT_FAIL, %EXPORT_TAGS, and $VERSION), the @ISA
+array I<must> be a package-scoped global and not a file-scoped lexical
+created via my(). Most classes have just one item in their @ISA array.
+In this case, we have what's called "single inheritance", or SI for short.
+
+Consider this class:
+
+ package Employee;
+ use Person;
+ @ISA = ("Person");
+ 1;
+
+Not a lot to it, eh? All it's doing so far is loading in another
+class and stating that this one will inherit methods from that
+other class if need be. We have given it none of its own methods.
+We rely upon an Employee to behave just like a Person.
+
+Setting up an empty class like this is called the "empty subclass test";
+that is, making a derived class that does nothing but inherit from a
+base class. If the original base class has been designed properly,
+then the new derived class can be used as a drop-in replacement for the
+old one. This means you should be able to write a program like this:
+
+ use Employee;
+ my $empl = Employee->new();
+ $empl->name("Jason");
+ $empl->age(23);
+ printf "%s is age %d.\n", $empl->name, $empl->age;
+
+By proper design, we mean always using the two-argument form of bless(),
+avoiding direct access of global data, and not exporting anything. If you
+look back at the Person::new() function we defined above, we were careful
+to do that. There's a bit of package data used in the constructor,
+but the reference to this is stored on the object itself and all other
+methods access package data via that reference, so we should be ok.
+
+What do we mean by the Person::new() function? Isn't that actually
+a method? Well, in principle, yes. A method is just a function that
+expects as its first argument a class name (package) or object
+(blessed reference). Person::new() is the function that both the
+C<< Person->new() >> method and the C<< Employee->new() >> method end
+up calling. Understand that while a method call looks a lot like a
+function call, they aren't really quite the same, and if you treat them
+as the same, you'll very soon be left with nothing but broken programs.
+First, the actual underlying calling conventions are different: method
+calls get an extra argument. Second, function calls don't do inheritance,
+but methods do.
+
+ Method Call Resulting Function Call
+ ----------- ------------------------
+ Person->new() Person::new("Person")
+ Employee->new() Person::new("Employee")
+
+So don't use function calls when you mean to call a method.
+
+If an employee is just a Person, that's not all too very interesting.
+So let's add some other methods. We'll give our employee
+data fields to access their salary, their employee ID, and their
+start date.
+
+If you're getting a little tired of creating all these nearly identical
+methods just to get at the object's data, do not despair. Later,
+we'll describe several different convenience mechanisms for shortening
+this up. Meanwhile, here's the straight-forward way:
+
+ sub salary {
+ my $self = shift;
+ if (@_) { $self->{SALARY} = shift }
+ return $self->{SALARY};
+ }
+
+ sub id_number {
+ my $self = shift;
+ if (@_) { $self->{ID} = shift }
+ return $self->{ID};
+ }
+
+ sub start_date {
+ my $self = shift;
+ if (@_) { $self->{START_DATE} = shift }
+ return $self->{START_DATE};
+ }
+
+=head2 Overridden Methods
+
+What happens when both a derived class and its base class have the same
+method defined? Well, then you get the derived class's version of that
+method. For example, let's say that we want the peers() method called on
+an employee to act a bit differently. Instead of just returning the list
+of peer names, let's return slightly different strings. So doing this:
+
+ $empl->peers("Peter", "Paul", "Mary");
+ printf "His peers are: %s\n", join(", ", $empl->peers);
+
+will produce:
+
+ His peers are: PEON=PETER, PEON=PAUL, PEON=MARY
+
+To do this, merely add this definition into the Employee.pm file:
+
+ sub peers {
+ my $self = shift;
+ if (@_) { @{ $self->{PEERS} } = @_ }
+ return map { "PEON=\U$_" } @{ $self->{PEERS} };
+ }
+
+There, we've just demonstrated the high-falutin' concept known in certain
+circles as I<polymorphism>. We've taken on the form and behaviour of
+an existing object, and then we've altered it to suit our own purposes.
+This is a form of Laziness. (Getting polymorphed is also what happens
+when the wizard decides you'd look better as a frog.)
+
+Every now and then you'll want to have a method call trigger both its
+derived class (also known as "subclass") version as well as its base class
+(also known as "superclass") version. In practice, constructors and
+destructors are likely to want to do this, and it probably also makes
+sense in the debug() method we showed previously.
+
+To do this, add this to Employee.pm:
+
+ use Carp;
+ my $Debugging = 0;
+
+ sub debug {
+ my $self = shift;
+ confess "usage: thing->debug(level)" unless @_ == 1;
+ my $level = shift;
+ if (ref($self)) {
+ $self->{"_DEBUG"} = $level;
+ } else {
+ $Debugging = $level; # whole class
+ }
+ Person::debug($self, $Debugging); # don't really do this
+ }
+
+As you see, we turn around and call the Person package's debug() function.
+But this is far too fragile for good design. What if Person doesn't
+have a debug() function, but is inheriting I<its> debug() method
+from elsewhere? It would have been slightly better to say
+
+ Person->debug($Debugging);
+
+But even that's got too much hard-coded. It's somewhat better to say
+
+ $self->Person::debug($Debugging);
+
+Which is a funny way to say to start looking for a debug() method up
+in Person. This strategy is more often seen on overridden object methods
+than on overridden class methods.
+
+There is still something a bit off here. We've hard-coded our
+superclass's name. This in particular is bad if you change which classes
+you inherit from, or add others. Fortunately, the pseudoclass SUPER
+comes to the rescue here.
+
+ $self->SUPER::debug($Debugging);
+
+This way it starts looking in my class's @ISA. This only makes sense
+from I<within> a method call, though. Don't try to access anything
+in SUPER:: from anywhere else, because it doesn't exist outside
+an overridden method call. Note that C<SUPER> refers to the superclass of
+the current package, I<not> to the superclass of C<$self>.
+
+Things are getting a bit complicated here. Have we done anything
+we shouldn't? As before, one way to test whether we're designing
+a decent class is via the empty subclass test. Since we already have
+an Employee class that we're trying to check, we'd better get a new
+empty subclass that can derive from Employee. Here's one:
+
+ package Boss;
+ use Employee; # :-)
+ @ISA = qw(Employee);
+
+And here's the test program:
+
+ #!/usr/bin/perl -w
+ use strict;
+ use Boss;
+ Boss->debug(1);
+
+ my $boss = Boss->new();
+
+ $boss->fullname->title("Don");
+ $boss->fullname->surname("Pichon Alvarez");
+ $boss->fullname->christian("Federico Jesus");
+ $boss->fullname->nickname("Fred");
+
+ $boss->age(47);
+ $boss->peers("Frank", "Felipe", "Faust");
+
+ printf "%s is age %d.\n", $boss->fullname->as_string, $boss->age;
+ printf "His peers are: %s\n", join(", ", $boss->peers);
+
+Running it, we see that we're still ok. If you'd like to dump out your
+object in a nice format, somewhat like the way the 'x' command works in
+the debugger, you could use the Data::Dumper module from CPAN this way:
+
+ use Data::Dumper;
+ print "Here's the boss:\n";
+ print Dumper($boss);
+
+Which shows us something like this:
+
+ Here's the boss:
+ $VAR1 = bless( {
+ _CENSUS => \1,
+ FULLNAME => bless( {
+ TITLE => 'Don',
+ SURNAME => 'Pichon Alvarez',
+ NICK => 'Fred',
+ CHRISTIAN => 'Federico Jesus'
+ }, 'Fullname' ),
+ AGE => 47,
+ PEERS => [
+ 'Frank',
+ 'Felipe',
+ 'Faust'
+ ]
+ }, 'Boss' );
+
+Hm.... something's missing there. What about the salary, start date,
+and ID fields? Well, we never set them to anything, even undef, so they
+don't show up in the hash's keys. The Employee class has no new() method
+of its own, and the new() method in Person doesn't know about Employees.
+(Nor should it: proper OO design dictates that a subclass be allowed to
+know about its immediate superclass, but never vice-versa.) So let's
+fix up Employee::new() this way:
+
+ sub new {
+ my $class = shift;
+ my $self = $class->SUPER::new();
+ $self->{SALARY} = undef;
+ $self->{ID} = undef;
+ $self->{START_DATE} = undef;
+ bless ($self, $class); # reconsecrate
+ return $self;
+ }
+
+Now if you dump out an Employee or Boss object, you'll find
+that new fields show up there now.
+
+=head2 Multiple Inheritance
+
+Ok, at the risk of confusing beginners and annoying OO gurus, it's
+time to confess that Perl's object system includes that controversial
+notion known as multiple inheritance, or MI for short. All this means
+is that rather than having just one parent class who in turn might
+itself have a parent class, etc., that you can directly inherit from
+two or more parents. It's true that some uses of MI can get you into
+trouble, although hopefully not quite so much trouble with Perl as with
+dubiously-OO languages like C++.
+
+The way it works is actually pretty simple: just put more than one package
+name in your @ISA array. When it comes time for Perl to go finding
+methods for your object, it looks at each of these packages in order.
+Well, kinda. It's actually a fully recursive, depth-first order by
+default (see L<mro> for alternate method resolution orders).
+Consider a bunch of @ISA arrays like this:
+
+ @First::ISA = qw( Alpha );
+ @Second::ISA = qw( Beta );
+ @Third::ISA = qw( First Second );
+
+If you have an object of class Third:
+
+ my $ob = Third->new();
+ $ob->spin();
+
+How do we find a spin() method (or a new() method for that matter)?
+Because the search is depth-first, classes will be looked up
+in the following order: Third, First, Alpha, Second, and Beta.
+
+In practice, few class modules have been seen that actually
+make use of MI. One nearly always chooses simple containership of
+one class within another over MI. That's why our Person
+object I<contained> a Fullname object. That doesn't mean
+it I<was> one.
+
+However, there is one particular area where MI in Perl is rampant:
+borrowing another class's class methods. This is rather common,
+especially with some bundled "objectless" classes,
+like Exporter, DynaLoader, AutoLoader, and SelfLoader. These classes
+do not provide constructors; they exist only so you may inherit their
+class methods. (It's not entirely clear why inheritance was done
+here rather than traditional module importation.)
+
+For example, here is the POSIX module's @ISA:
+
+ package POSIX;
+ @ISA = qw(Exporter DynaLoader);
+
+The POSIX module isn't really an object module, but then,
+neither are Exporter or DynaLoader. They're just lending their
+classes' behaviours to POSIX.
+
+Why don't people use MI for object methods much? One reason is that
+it can have complicated side-effects. For one thing, your inheritance
+graph (no longer a tree) might converge back to the same base class.
+Although Perl guards against recursive inheritance, merely having parents
+who are related to each other via a common ancestor, incestuous though
+it sounds, is not forbidden. What if in our Third class shown above we
+wanted its new() method to also call both overridden constructors in its
+two parent classes? The SUPER notation would only find the first one.
+Also, what about if the Alpha and Beta classes both had a common ancestor,
+like Nought? If you kept climbing up the inheritance tree calling
+overridden methods, you'd end up calling Nought::new() twice,
+which might well be a bad idea.
+
+=head2 UNIVERSAL: The Root of All Objects
+
+Wouldn't it be convenient if all objects were rooted at some ultimate
+base class? That way you could give every object common methods without
+having to go and add it to each and every @ISA. Well, it turns out that
+you can. You don't see it, but Perl tacitly and irrevocably assumes
+that there's an extra element at the end of @ISA: the class UNIVERSAL.
+In version 5.003, there were no predefined methods there, but you could put
+whatever you felt like into it.
+
+However, as of version 5.004 (or some subversive releases, like 5.003_08),
+UNIVERSAL has some methods in it already. These are builtin to your Perl
+binary, so they don't take any extra time to load. Predefined methods
+include isa(), can(), and VERSION(). isa() tells you whether an object or
+class "is" another one without having to traverse the hierarchy yourself:
+
+ $has_io = $fd->isa("IO::Handle");
+ $itza_handle = IO::Socket->isa("IO::Handle");
+
+The can() method, called against that object or class, reports back
+whether its string argument is a callable method name in that class.
+In fact, it gives you back a function reference to that method:
+
+ $his_print_method = $obj->can('as_string');
+
+Finally, the VERSION method checks whether the class (or the object's
+class) has a package global called $VERSION that's high enough, as in:
+
+ Some_Module->VERSION(3.0);
+ $his_vers = $ob->VERSION();
+
+However, we don't usually call VERSION ourselves. (Remember that an all
+uppercase function name is a Perl convention that indicates that the
+function will be automatically used by Perl in some way.) In this case,
+it happens when you say
+
+ use Some_Module 3.0;
+
+If you wanted to add version checking to your Person class explained
+above, just add this to Person.pm:
+
+ our $VERSION = '1.1';
+
+and then in Employee.pm you can say
+
+ use Person 1.1;
+
+And it would make sure that you have at least that version number or
+higher available. This is not the same as loading in that exact version
+number. No mechanism currently exists for concurrent installation of
+multiple versions of a module. Lamentably.
+
+=head2 Deeper UNIVERSAL details
+
+It is also valid (though perhaps unwise in most cases) to put other
+packages' names in @UNIVERSAL::ISA. These packages will also be
+implicitly inherited by all classes, just as UNIVERSAL itself is.
+However, neither UNIVERSAL nor any of its parents from the @ISA tree
+are explicit base classes of all objects. To clarify, given the
+following:
+
+ @UNIVERSAL::ISA = ('REALLYUNIVERSAL');
+
+ package REALLYUNIVERSAL;
+ sub special_method { return "123" }
+
+ package Foo;
+ sub normal_method { return "321" }
+
+Calling Foo->special_method() will return "123", but calling
+Foo->isa('REALLYUNIVERSAL') or Foo->isa('UNIVERSAL') will return
+false.
+
+If your class is using an alternate mro like C3 (see
+L<mro>), method resolution within UNIVERSAL / @UNIVERSAL::ISA will
+still occur in the default depth-first left-to-right manner,
+after the class's C3 mro is exhausted.
+
+All of the above is made more intuitive by realizing what really
+happens during method lookup, which is roughly like this
+ugly pseudo-code:
+
+ get_mro(class) {
+ # recurses down the @ISA's starting at class,
+ # builds a single linear array of all
+ # classes to search in the appropriate order.
+ # The method resolution order (mro) to use
+ # for the ordering is whichever mro "class"
+ # has set on it (either default (depth first
+ # l-to-r) or C3 ordering).
+ # The first entry in the list is the class
+ # itself.
+ }
+
+ find_method(class, methname) {
+ foreach $class (get_mro(class)) {
+ if($class->has_method(methname)) {
+ return ref_to($class->$methname);
+ }
+ }
+ foreach $class (get_mro(UNIVERSAL)) {
+ if($class->has_method(methname)) {
+ return ref_to($class->$methname);
+ }
+ }
+ return undef;
+ }
+
+However the code that implements UNIVERSAL::isa does not
+search in UNIVERSAL itself, only in the package's actual
+@ISA.
+
+=head1 Alternate Object Representations
+
+Nothing requires objects to be implemented as hash references. An object
+can be any sort of reference so long as its referent has been suitably
+blessed. That means scalar, array, and code references are also fair
+game.
+
+A scalar would work if the object has only one datum to hold. An array
+would work for most cases, but makes inheritance a bit dodgy because
+you have to invent new indices for the derived classes.
+
+=head2 Arrays as Objects
+
+If the user of your class honors the contract and sticks to the advertised
+interface, then you can change its underlying interface if you feel
+like it. Here's another implementation that conforms to the same
+interface specification. This time we'll use an array reference
+instead of a hash reference to represent the object.
+
+ package Person;
+ use strict;
+
+ my($NAME, $AGE, $PEERS) = ( 0 .. 2 );
+
+ ############################################
+ ## the object constructor (array version) ##
+ ############################################
+ sub new {
+ my $self = [];
+ $self->[$NAME] = undef; # this is unnecessary
+ $self->[$AGE] = undef; # as is this
+ $self->[$PEERS] = []; # but this isn't, really
+ bless($self);
+ return $self;
+ }
+
+ sub name {
+ my $self = shift;
+ if (@_) { $self->[$NAME] = shift }
+ return $self->[$NAME];
+ }
+
+ sub age {
+ my $self = shift;
+ if (@_) { $self->[$AGE] = shift }
+ return $self->[$AGE];
+ }
+
+ sub peers {
+ my $self = shift;
+ if (@_) { @{ $self->[$PEERS] } = @_ }
+ return @{ $self->[$PEERS] };
+ }
+
+ 1; # so the require or use succeeds
+
+You might guess that the array access would be a lot faster than the
+hash access, but they're actually comparable. The array is a I<little>
+bit faster, but not more than ten or fifteen percent, even when you
+replace the variables above like $AGE with literal numbers, like 1.
+A bigger difference between the two approaches can be found in memory use.
+A hash representation takes up more memory than an array representation
+because you have to allocate memory for the keys as well as for the values.
+However, it really isn't that bad, especially since as of version 5.004,
+memory is only allocated once for a given hash key, no matter how many
+hashes have that key. It's expected that sometime in the future, even
+these differences will fade into obscurity as more efficient underlying
+representations are devised.
+
+Still, the tiny edge in speed (and somewhat larger one in memory)
+is enough to make some programmers choose an array representation
+for simple classes. There's still a little problem with
+scalability, though, because later in life when you feel
+like creating subclasses, you'll find that hashes just work
+out better.
+
+=head2 Closures as Objects
+
+Using a code reference to represent an object offers some fascinating
+possibilities. We can create a new anonymous function (closure) who
+alone in all the world can see the object's data. This is because we
+put the data into an anonymous hash that's lexically visible only to
+the closure we create, bless, and return as the object. This object's
+methods turn around and call the closure as a regular subroutine call,
+passing it the field we want to affect. (Yes,
+the double-function call is slow, but if you wanted fast, you wouldn't
+be using objects at all, eh? :-)
+
+Use would be similar to before:
+
+ use Person;
+ $him = Person->new();
+ $him->name("Jason");
+ $him->age(23);
+ $him->peers( [ "Norbert", "Rhys", "Phineas" ] );
+ printf "%s is %d years old.\n", $him->name, $him->age;
+ print "His peers are: ", join(", ", @{$him->peers}), "\n";
+
+but the implementation would be radically, perhaps even sublimely
+different:
+
+ package Person;
+
+ sub new {
+ my $class = shift;
+ my $self = {
+ NAME => undef,
+ AGE => undef,
+ PEERS => [],
+ };
+ my $closure = sub {
+ my $field = shift;
+ if (@_) { $self->{$field} = shift }
+ return $self->{$field};
+ };
+ bless($closure, $class);
+ return $closure;
+ }
+
+ sub name { &{ $_[0] }("NAME", @_[ 1 .. $#_ ] ) }
+ sub age { &{ $_[0] }("AGE", @_[ 1 .. $#_ ] ) }
+ sub peers { &{ $_[0] }("PEERS", @_[ 1 .. $#_ ] ) }
+
+ 1;
+
+Because this object is hidden behind a code reference, it's probably a bit
+mysterious to those whose background is more firmly rooted in standard
+procedural or object-based programming languages than in functional
+programming languages whence closures derive. The object
+created and returned by the new() method is itself not a data reference
+as we've seen before. It's an anonymous code reference that has within
+it access to a specific version (lexical binding and instantiation)
+of the object's data, which are stored in the private variable $self.
+Although this is the same function each time, it contains a different
+version of $self.
+
+When a method like C<$him-E<gt>name("Jason")> is called, its implicit
+zeroth argument is the invoking object--just as it is with all method
+calls. But in this case, it's our code reference (something like a
+function pointer in C++, but with deep binding of lexical variables).
+There's not a lot to be done with a code reference beyond calling it, so
+that's just what we do when we say C<&{$_[0]}>. This is just a regular
+function call, not a method call. The initial argument is the string
+"NAME", and any remaining arguments are whatever had been passed to the
+method itself.
+
+Once we're executing inside the closure that had been created in new(),
+the $self hash reference suddenly becomes visible. The closure grabs
+its first argument ("NAME" in this case because that's what the name()
+method passed it), and uses that string to subscript into the private
+hash hidden in its unique version of $self.
+
+Nothing under the sun will allow anyone outside the executing method to
+be able to get at this hidden data. Well, nearly nothing. You I<could>
+single step through the program using the debugger and find out the
+pieces while you're in the method, but everyone else is out of luck.
+
+There, if that doesn't excite the Scheme folks, then I just don't know
+what will. Translation of this technique into C++, Java, or any other
+braindead-static language is left as a futile exercise for aficionados
+of those camps.
+
+You could even add a bit of nosiness via the caller() function and
+make the closure refuse to operate unless called via its own package.
+This would no doubt satisfy certain fastidious concerns of programming
+police and related puritans.
+
+If you were wondering when Hubris, the third principle virtue of a
+programmer, would come into play, here you have it. (More seriously,
+Hubris is just the pride in craftsmanship that comes from having written
+a sound bit of well-designed code.)
+
+=head1 AUTOLOAD: Proxy Methods
+
+Autoloading is a way to intercept calls to undefined methods. An autoload
+routine may choose to create a new function on the fly, either loaded
+from disk or perhaps just eval()ed right there. This define-on-the-fly
+strategy is why it's called autoloading.
+
+But that's only one possible approach. Another one is to just
+have the autoloaded method itself directly provide the
+requested service. When used in this way, you may think
+of autoloaded methods as "proxy" methods.
+
+When Perl tries to call an undefined function in a particular package
+and that function is not defined, it looks for a function in
+that same package called AUTOLOAD. If one exists, it's called
+with the same arguments as the original function would have had.
+The fully-qualified name of the function is stored in that package's
+global variable $AUTOLOAD. Once called, the function can do anything
+it would like, including defining a new function by the right name, and
+then doing a really fancy kind of C<goto> right to it, erasing itself
+from the call stack.
+
+What does this have to do with objects? After all, we keep talking about
+functions, not methods. Well, since a method is just a function with
+an extra argument and some fancier semantics about where it's found,
+we can use autoloading for methods, too. Perl doesn't start looking
+for an AUTOLOAD method until it has exhausted the recursive hunt up
+through @ISA, though. Some programmers have even been known to define
+a UNIVERSAL::AUTOLOAD method to trap unresolved method calls to any
+kind of object.
+
+=head2 Autoloaded Data Methods
+
+You probably began to get a little suspicious about the duplicated
+code way back earlier when we first showed you the Person class, and
+then later the Employee class. Each method used to access the
+hash fields looked virtually identical. This should have tickled
+that great programming virtue, Impatience, but for the time,
+we let Laziness win out, and so did nothing. Proxy methods can cure
+this.
+
+Instead of writing a new function every time we want a new data field,
+we'll use the autoload mechanism to generate (actually, mimic) methods on
+the fly. To verify that we're accessing a valid member, we will check
+against an C<_permitted> (pronounced "under-permitted") field, which
+is a reference to a file-scoped lexical (like a C file static) hash of permitted fields in this record
+called %fields. Why the underscore? For the same reason as the _CENSUS
+field we once used: as a marker that means "for internal use only".
+
+Here's what the module initialization code and class
+constructor will look like when taking this approach:
+
+ package Person;
+ use Carp;
+ our $AUTOLOAD; # it's a package global
+
+ my %fields = (
+ name => undef,
+ age => undef,
+ peers => undef,
+ );
+
+ sub new {
+ my $class = shift;
+ my $self = {
+ _permitted => \%fields,
+ %fields,
+ };
+ bless $self, $class;
+ return $self;
+ }
+
+If we wanted our record to have default values, we could fill those in
+where current we have C<undef> in the %fields hash.
+
+Notice how we saved a reference to our class data on the object itself?
+Remember that it's important to access class data through the object
+itself instead of having any method reference %fields directly, or else
+you won't have a decent inheritance.
+
+The real magic, though, is going to reside in our proxy method, which
+will handle all calls to undefined methods for objects of class Person
+(or subclasses of Person). It has to be called AUTOLOAD. Again, it's
+all caps because it's called for us implicitly by Perl itself, not by
+a user directly.
+
+ sub AUTOLOAD {
+ my $self = shift;
+ my $type = ref($self)
+ or croak "$self is not an object";
+
+ my $name = $AUTOLOAD;
+ $name =~ s/.*://; # strip fully-qualified portion
+
+ unless (exists $self->{_permitted}->{$name} ) {
+ croak "Can't access `$name' field in class $type";
+ }
+
+ if (@_) {
+ return $self->{$name} = shift;
+ } else {
+ return $self->{$name};
+ }
+ }
+
+Pretty nifty, eh? All we have to do to add new data fields
+is modify %fields. No new functions need be written.
+
+I could have avoided the C<_permitted> field entirely, but I
+wanted to demonstrate how to store a reference to class data on the
+object so you wouldn't have to access that class data
+directly from an object method.
+
+=head2 Inherited Autoloaded Data Methods
+
+But what about inheritance? Can we define our Employee
+class similarly? Yes, so long as we're careful enough.
+
+Here's how to be careful:
+
+ package Employee;
+ use Person;
+ use strict;
+ our @ISA = qw(Person);
+
+ my %fields = (
+ id => undef,
+ salary => undef,
+ );
+
+ sub new {
+ my $class = shift;
+ my $self = $class->SUPER::new();
+ my($element);
+ foreach $element (keys %fields) {
+ $self->{_permitted}->{$element} = $fields{$element};
+ }
+ @{$self}{keys %fields} = values %fields;
+ return $self;
+ }
+
+Once we've done this, we don't even need to have an
+AUTOLOAD function in the Employee package, because
+we'll grab Person's version of that via inheritance,
+and it will all work out just fine.
+
+=head1 Metaclassical Tools
+
+Even though proxy methods can provide a more convenient approach to making
+more struct-like classes than tediously coding up data methods as
+functions, it still leaves a bit to be desired. For one thing, it means
+you have to handle bogus calls that you don't mean to trap via your proxy.
+It also means you have to be quite careful when dealing with inheritance,
+as detailed above.
+
+Perl programmers have responded to this by creating several different
+class construction classes. These metaclasses are classes
+that create other classes. A couple worth looking at are
+Class::Struct and Alias. These and other related metaclasses can be
+found in the modules directory on CPAN.
+
+=head2 Class::Struct
+
+One of the older ones is Class::Struct. In fact, its syntax and
+interface were sketched out long before perl5 even solidified into a
+real thing. What it does is provide you a way to "declare" a class
+as having objects whose fields are of a specific type. The function
+that does this is called, not surprisingly enough, struct(). Because
+structures or records are not base types in Perl, each time you want to
+create a class to provide a record-like data object, you yourself have
+to define a new() method, plus separate data-access methods for each of
+that record's fields. You'll quickly become bored with this process.
+The Class::Struct::struct() function alleviates this tedium.
+
+Here's a simple example of using it:
+
+ use Class::Struct qw(struct);
+ use Jobbie; # user-defined; see below
+
+ struct 'Fred' => {
+ one => '$',
+ many => '@',
+ profession => 'Jobbie', # does not call Jobbie->new()
+ };
+
+ $ob = Fred->new(profession => Jobbie->new());
+ $ob->one("hmmmm");
+
+ $ob->many(0, "here");
+ $ob->many(1, "you");
+ $ob->many(2, "go");
+ print "Just set: ", $ob->many(2), "\n";
+
+ $ob->profession->salary(10_000);
+
+You can declare types in the struct to be basic Perl types, or
+user-defined types (classes). User types will be initialized by calling
+that class's new() method.
+
+Take care that the C<Jobbie> object is not created automatically by the
+C<Fred> class's new() method, so you should specify a C<Jobbie> object
+when you create an instance of C<Fred>.
+
+Here's a real-world example of using struct generation. Let's say you
+wanted to override Perl's idea of gethostbyname() and gethostbyaddr() so
+that they would return objects that acted like C structures. We don't
+care about high-falutin' OO gunk. All we want is for these objects to
+act like structs in the C sense.
+
+ use Socket;
+ use Net::hostent;
+ $h = gethostbyname("perl.com"); # object return
+ printf "perl.com's real name is %s, address %s\n",
+ $h->name, inet_ntoa($h->addr);
+
+Here's how to do this using the Class::Struct module.
+The crux is going to be this call:
+
+ struct 'Net::hostent' => [ # note bracket
+ name => '$',
+ aliases => '@',
+ addrtype => '$',
+ 'length' => '$',
+ addr_list => '@',
+ ];
+
+Which creates object methods of those names and types.
+It even creates a new() method for us.
+
+We could also have implemented our object this way:
+
+ struct 'Net::hostent' => { # note brace
+ name => '$',
+ aliases => '@',
+ addrtype => '$',
+ 'length' => '$',
+ addr_list => '@',
+ };
+
+and then Class::Struct would have used an anonymous hash as the object
+type, instead of an anonymous array. The array is faster and smaller,
+but the hash works out better if you eventually want to do inheritance.
+Since for this struct-like object we aren't planning on inheritance,
+this time we'll opt for better speed and size over better flexibility.
+
+Here's the whole implementation:
+
+ package Net::hostent;
+ use strict;
+
+ BEGIN {
+ use Exporter ();
+ our @EXPORT = qw(gethostbyname gethostbyaddr gethost);
+ our @EXPORT_OK = qw(
+ $h_name @h_aliases
+ $h_addrtype $h_length
+ @h_addr_list $h_addr
+ );
+ our %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] );
+ }
+ our @EXPORT_OK;
+
+ # Class::Struct forbids use of @ISA
+ sub import { goto &Exporter::import }
+
+ use Class::Struct qw(struct);
+ struct 'Net::hostent' => [
+ name => '$',
+ aliases => '@',
+ addrtype => '$',
+ 'length' => '$',
+ addr_list => '@',
+ ];
+
+ sub addr { shift->addr_list->[0] }
+
+ sub populate (@) {
+ return unless @_;
+ my $hob = new(); # Class::Struct made this!
+ $h_name = $hob->[0] = $_[0];
+ @h_aliases = @{ $hob->[1] } = split ' ', $_[1];
+ $h_addrtype = $hob->[2] = $_[2];
+ $h_length = $hob->[3] = $_[3];
+ $h_addr = $_[4];
+ @h_addr_list = @{ $hob->[4] } = @_[ (4 .. $#_) ];
+ return $hob;
+ }
+
+ sub gethostbyname ($) { populate(CORE::gethostbyname(shift)) }
+
+ sub gethostbyaddr ($;$) {
+ my ($addr, $addrtype);
+ $addr = shift;
+ require Socket unless @_;
+ $addrtype = @_ ? shift : Socket::AF_INET();
+ populate(CORE::gethostbyaddr($addr, $addrtype))
+ }
+
+ sub gethost($) {
+ if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) {
+ require Socket;
+ &gethostbyaddr(Socket::inet_aton(shift));
+ } else {
+ &gethostbyname;
+ }
+ }
+
+ 1;
+
+We've snuck in quite a fair bit of other concepts besides just dynamic
+class creation, like overriding core functions, import/export bits,
+function prototyping, short-cut function call via C<&whatever>, and
+function replacement with C<goto &whatever>. These all mostly make
+sense from the perspective of a traditional module, but as you can see,
+we can also use them in an object module.
+
+You can look at other object-based, struct-like overrides of core
+functions in the 5.004 release of Perl in File::stat, Net::hostent,
+Net::netent, Net::protoent, Net::servent, Time::gmtime, Time::localtime,
+User::grent, and User::pwent. These modules have a final component
+that's all lowercase, by convention reserved for compiler pragmas,
+because they affect the compilation and change a builtin function.
+They also have the type names that a C programmer would most expect.
+
+=head2 Data Members as Variables
+
+If you're used to C++ objects, then you're accustomed to being able to
+get at an object's data members as simple variables from within a method.
+The Alias module provides for this, as well as a good bit more, such
+as the possibility of private methods that the object can call but folks
+outside the class cannot.
+
+Here's an example of creating a Person using the Alias module.
+When you update these magical instance variables, you automatically
+update value fields in the hash. Convenient, eh?
+
+ package Person;
+
+ # this is the same as before...
+ sub new {
+ my $class = shift;
+ my $self = {
+ NAME => undef,
+ AGE => undef,
+ PEERS => [],
+ };
+ bless($self, $class);
+ return $self;
+ }
+
+ use Alias qw(attr);
+ our ($NAME, $AGE, $PEERS);
+
+ sub name {
+ my $self = attr shift;
+ if (@_) { $NAME = shift; }
+ return $NAME;
+ }
+
+ sub age {
+ my $self = attr shift;
+ if (@_) { $AGE = shift; }
+ return $AGE;
+ }
+
+ sub peers {
+ my $self = attr shift;
+ if (@_) { @PEERS = @_; }
+ return @PEERS;
+ }
+
+ sub exclaim {
+ my $self = attr shift;
+ return sprintf "Hi, I'm %s, age %d, working with %s",
+ $NAME, $AGE, join(", ", @PEERS);
+ }
+
+ sub happy_birthday {
+ my $self = attr shift;
+ return ++$AGE;
+ }
+
+The need for the C<our> declaration is because what Alias does
+is play with package globals with the same name as the fields. To use
+globals while C<use strict> is in effect, you have to predeclare them.
+These package variables are localized to the block enclosing the attr()
+call just as if you'd used a local() on them. However, that means that
+they're still considered global variables with temporary values, just
+as with any other local().
+
+It would be nice to combine Alias with
+something like Class::Struct or Class::MethodMaker.
+
+=head1 NOTES
+
+=head2 Object Terminology
+
+In the various OO literature, it seems that a lot of different words
+are used to describe only a few different concepts. If you're not
+already an object programmer, then you don't need to worry about all
+these fancy words. But if you are, then you might like to know how to
+get at the same concepts in Perl.
+
+For example, it's common to call an object an I<instance> of a class
+and to call those objects' methods I<instance methods>. Data fields
+peculiar to each object are often called I<instance data> or I<object
+attributes>, and data fields common to all members of that class are
+I<class data>, I<class attributes>, or I<static data members>.
+
+Also, I<base class>, I<generic class>, and I<superclass> all describe
+the same notion, whereas I<derived class>, I<specific class>, and
+I<subclass> describe the other related one.
+
+C++ programmers have I<static methods> and I<virtual methods>,
+but Perl only has I<class methods> and I<object methods>.
+Actually, Perl only has methods. Whether a method gets used
+as a class or object method is by usage only. You could accidentally
+call a class method (one expecting a string argument) on an
+object (one expecting a reference), or vice versa.
+
+From the C++ perspective, all methods in Perl are virtual.
+This, by the way, is why they are never checked for function
+prototypes in the argument list as regular builtin and user-defined
+functions can be.
+
+Because a class is itself something of an object, Perl's classes can be
+taken as describing both a "class as meta-object" (also called I<object
+factory>) philosophy and the "class as type definition" (I<declaring>
+behaviour, not I<defining> mechanism) idea. C++ supports the latter
+notion, but not the former.
+
+=head1 SEE ALSO
+
+The following manpages will doubtless provide more
+background for this one:
+L<perlmod>,
+L<perlref>,
+L<perlobj>,
+L<perlbot>,
+L<perltie>,
+and
+L<overload>.
+
+L<perlboot> is a kinder, gentler introduction to object-oriented
+programming.
+
+L<perltooc> provides more detail on class data.
+
+Some modules which might prove interesting are Class::Accessor,
+Class::Class, Class::Contract, Class::Data::Inheritable,
+Class::MethodMaker and Tie::SecureHash
+
+
+=head1 AUTHOR AND COPYRIGHT
+
+Copyright (c) 1997, 1998 Tom Christiansen
+All rights reserved.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
+
+=head1 COPYRIGHT
+
+=head2 Acknowledgments
+
+Thanks to
+Larry Wall,
+Roderick Schertler,
+Gurusamy Sarathy,
+Dean Roehrich,
+Raphael Manfredi,
+Brent Halsey,
+Greg Bacon,
+Brad Appleton,
+and many others for their helpful comments.
diff --git a/Master/tlpkg/tlperl/lib/pods/perltrap.pod b/Master/tlpkg/tlperl/lib/pods/perltrap.pod
new file mode 100644
index 00000000000..b5f09351669
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltrap.pod
@@ -0,0 +1,1590 @@
+=head1 NAME
+
+perltrap - Perl traps for the unwary
+
+=head1 DESCRIPTION
+
+The biggest trap of all is forgetting to C<use warnings> or use the B<-w>
+switch; see L<perllexwarn> and L<perlrun>. The second biggest trap is not
+making your entire program runnable under C<use strict>. The third biggest
+trap is not reading the list of changes in this version of Perl; see
+L<perldelta>.
+
+=head2 Awk Traps
+
+Accustomed B<awk> users should take special note of the following:
+
+=over 4
+
+=item *
+
+A Perl program executes only once, not once for each input line. You can
+do an implicit loop with C<-n> or C<-p>.
+
+=item *
+
+The English module, loaded via
+
+ use English;
+
+allows you to refer to special variables (like C<$/>) with names (like
+$RS), as though they were in B<awk>; see L<perlvar> for details.
+
+=item *
+
+Semicolons are required after all simple statements in Perl (except
+at the end of a block). Newline is not a statement delimiter.
+
+=item *
+
+Curly brackets are required on C<if>s and C<while>s.
+
+=item *
+
+Variables begin with "$", "@" or "%" in Perl.
+
+=item *
+
+Arrays index from 0. Likewise string positions in substr() and
+index().
+
+=item *
+
+You have to decide whether your array has numeric or string indices.
+
+=item *
+
+Hash values do not spring into existence upon mere reference.
+
+=item *
+
+You have to decide whether you want to use string or numeric
+comparisons.
+
+=item *
+
+Reading an input line does not split it for you. You get to split it
+to an array yourself. And the split() operator has different
+arguments than B<awk>'s.
+
+=item *
+
+The current input line is normally in $_, not $0. It generally does
+not have the newline stripped. ($0 is the name of the program
+executed.) See L<perlvar>.
+
+=item *
+
+$<I<digit>> does not refer to fields--it refers to substrings matched
+by the last match pattern.
+
+=item *
+
+The print() statement does not add field and record separators unless
+you set C<$,> and C<$\>. You can set $OFS and $ORS if you're using
+the English module.
+
+=item *
+
+You must open your files before you print to them.
+
+=item *
+
+The range operator is "..", not comma. The comma operator works as in
+C.
+
+=item *
+
+The match operator is "=~", not "~". ("~" is the one's complement
+operator, as in C.)
+
+=item *
+
+The exponentiation operator is "**", not "^". "^" is the XOR
+operator, as in C. (You know, one could get the feeling that B<awk> is
+basically incompatible with C.)
+
+=item *
+
+The concatenation operator is ".", not the null string. (Using the
+null string would render C</pat/ /pat/> unparsable, because the third slash
+would be interpreted as a division operator--the tokenizer is in fact
+slightly context sensitive for operators like "/", "?", and ">".
+And in fact, "." itself can be the beginning of a number.)
+
+=item *
+
+The C<next>, C<exit>, and C<continue> keywords work differently.
+
+=item *
+
+
+The following variables work differently:
+
+ Awk Perl
+ ARGC scalar @ARGV (compare with $#ARGV)
+ ARGV[0] $0
+ FILENAME $ARGV
+ FNR $. - something
+ FS (whatever you like)
+ NF $#Fld, or some such
+ NR $.
+ OFMT $#
+ OFS $,
+ ORS $\
+ RLENGTH length($&)
+ RS $/
+ RSTART length($`)
+ SUBSEP $;
+
+=item *
+
+You cannot set $RS to a pattern, only a string.
+
+=item *
+
+When in doubt, run the B<awk> construct through B<a2p> and see what it
+gives you.
+
+=back
+
+=head2 C/C++ Traps
+
+Cerebral C and C++ programmers should take note of the following:
+
+=over 4
+
+=item *
+
+Curly brackets are required on C<if>'s and C<while>'s.
+
+=item *
+
+You must use C<elsif> rather than C<else if>.
+
+=item *
+
+The C<break> and C<continue> keywords from C become in Perl C<last>
+and C<next>, respectively. Unlike in C, these do I<not> work within a
+C<do { } while> construct. See L<perlsyn/"Loop Control">.
+
+=item *
+
+The switch statement is called C<given/when> and only available in
+perl 5.10 or newer. See L<perlsyn/"Switch statements">.
+
+=item *
+
+Variables begin with "$", "@" or "%" in Perl.
+
+=item *
+
+Comments begin with "#", not "/*" or "//". Perl may interpret C/C++
+comments as division operators, unterminated regular expressions or
+the defined-or operator.
+
+=item *
+
+You can't take the address of anything, although a similar operator
+in Perl is the backslash, which creates a reference.
+
+=item *
+
+C<ARGV> must be capitalized. C<$ARGV[0]> is C's C<argv[1]>, and C<argv[0]>
+ends up in C<$0>.
+
+=item *
+
+System calls such as link(), unlink(), rename(), etc. return nonzero for
+success, not 0. (system(), however, returns zero for success.)
+
+=item *
+
+Signal handlers deal with signal names, not numbers. Use C<kill -l>
+to find their names on your system.
+
+=back
+
+=head2 Sed Traps
+
+Seasoned B<sed> programmers should take note of the following:
+
+=over 4
+
+=item *
+
+A Perl program executes only once, not once for each input line. You can
+do an implicit loop with C<-n> or C<-p>.
+
+=item *
+
+Backreferences in substitutions use "$" rather than "\".
+
+=item *
+
+The pattern matching metacharacters "(", ")", and "|" do not have backslashes
+in front.
+
+=item *
+
+The range operator is C<...>, rather than comma.
+
+=back
+
+=head2 Shell Traps
+
+Sharp shell programmers should take note of the following:
+
+=over 4
+
+=item *
+
+The backtick operator does variable interpolation without regard to
+the presence of single quotes in the command.
+
+=item *
+
+The backtick operator does no translation of the return value, unlike B<csh>.
+
+=item *
+
+Shells (especially B<csh>) do several levels of substitution on each
+command line. Perl does substitution in only certain constructs
+such as double quotes, backticks, angle brackets, and search patterns.
+
+=item *
+
+Shells interpret scripts a little bit at a time. Perl compiles the
+entire program before executing it (except for C<BEGIN> blocks, which
+execute at compile time).
+
+=item *
+
+The arguments are available via @ARGV, not $1, $2, etc.
+
+=item *
+
+The environment is not automatically made available as separate scalar
+variables.
+
+=item *
+
+The shell's C<test> uses "=", "!=", "<" etc for string comparisons and "-eq",
+"-ne", "-lt" etc for numeric comparisons. This is the reverse of Perl, which
+uses C<eq>, C<ne>, C<lt> for string comparisons, and C<==>, C<!=> C<< < >> etc
+for numeric comparisons.
+
+=back
+
+=head2 Perl Traps
+
+Practicing Perl Programmers should take note of the following:
+
+=over 4
+
+=item *
+
+Remember that many operations behave differently in a list
+context than they do in a scalar one. See L<perldata> for details.
+
+=item *
+
+Avoid barewords if you can, especially all lowercase ones.
+You can't tell by just looking at it whether a bareword is
+a function or a string. By using quotes on strings and
+parentheses on function calls, you won't ever get them confused.
+
+=item *
+
+You cannot discern from mere inspection which builtins
+are unary operators (like chop() and chdir())
+and which are list operators (like print() and unlink()).
+(Unless prototyped, user-defined subroutines can B<only> be list
+operators, never unary ones.) See L<perlop> and L<perlsub>.
+
+=item *
+
+People have a hard time remembering that some functions
+default to $_, or @ARGV, or whatever, but that others which
+you might expect to do not.
+
+=item *
+
+The <FH> construct is not the name of the filehandle, it is a readline
+operation on that handle. The data read is assigned to $_ only if the
+file read is the sole condition in a while loop:
+
+ while (<FH>) { }
+ while (defined($_ = <FH>)) { }..
+ <FH>; # data discarded!
+
+=item *
+
+Remember not to use C<=> when you need C<=~>;
+these two constructs are quite different:
+
+ $x = /foo/;
+ $x =~ /foo/;
+
+=item *
+
+The C<do {}> construct isn't a real loop that you can use
+loop control on.
+
+=item *
+
+Use C<my()> for local variables whenever you can get away with
+it (but see L<perlform> for where you can't).
+Using C<local()> actually gives a local value to a global
+variable, which leaves you open to unforeseen side-effects
+of dynamic scoping.
+
+=item *
+
+If you localize an exported variable in a module, its exported value will
+not change. The local name becomes an alias to a new value but the
+external name is still an alias for the original.
+
+=back
+
+=head2 Perl4 to Perl5 Traps
+
+Practicing Perl4 Programmers should take note of the following
+Perl4-to-Perl5 specific traps.
+
+They're crudely ordered according to the following list:
+
+=over 4
+
+=item Discontinuance, Deprecation, and BugFix traps
+
+Anything that's been fixed as a perl4 bug, removed as a perl4 feature
+or deprecated as a perl4 feature with the intent to encourage usage of
+some other perl5 feature.
+
+=item Parsing Traps
+
+Traps that appear to stem from the new parser.
+
+=item Numerical Traps
+
+Traps having to do with numerical or mathematical operators.
+
+=item General data type traps
+
+Traps involving perl standard data types.
+
+=item Context Traps - scalar, list contexts
+
+Traps related to context within lists, scalar statements/declarations.
+
+=item Precedence Traps
+
+Traps related to the precedence of parsing, evaluation, and execution of
+code.
+
+=item General Regular Expression Traps using s///, etc.
+
+Traps related to the use of pattern matching.
+
+=item Subroutine, Signal, Sorting Traps
+
+Traps related to the use of signals and signal handlers, general subroutines,
+and sorting, along with sorting subroutines.
+
+=item OS Traps
+
+OS-specific traps.
+
+=item DBM Traps
+
+Traps specific to the use of C<dbmopen()>, and specific dbm implementations.
+
+=item Unclassified Traps
+
+Everything else.
+
+=back
+
+If you find an example of a conversion trap that is not listed here,
+please submit it to <F<perlbug@perl.org>> for inclusion.
+Also note that at least some of these can be caught with the
+C<use warnings> pragma or the B<-w> switch.
+
+=head2 Discontinuance, Deprecation, and BugFix traps
+
+Anything that has been discontinued, deprecated, or fixed as
+a bug from perl4.
+
+=over 4
+
+=item * Symbols starting with "_" no longer forced into main
+
+Symbols starting with "_" are no longer forced into package main, except
+for C<$_> itself (and C<@_>, etc.).
+
+ package test;
+ $_legacy = 1;
+
+ package main;
+ print "\$_legacy is ",$_legacy,"\n";
+
+ # perl4 prints: $_legacy is 1
+ # perl5 prints: $_legacy is
+
+=item * Double-colon valid package separator in variable name
+
+Double-colon is now a valid package separator in a variable name. Thus these
+behave differently in perl4 vs. perl5, because the packages don't exist.
+
+ $a=1;$b=2;$c=3;$var=4;
+ print "$a::$b::$c ";
+ print "$var::abc::xyz\n";
+
+ # perl4 prints: 1::2::3 4::abc::xyz
+ # perl5 prints: 3
+
+Given that C<::> is now the preferred package delimiter, it is debatable
+whether this should be classed as a bug or not.
+(The older package delimiter, ' ,is used here)
+
+ $x = 10;
+ print "x=${'x}\n";
+
+ # perl4 prints: x=10
+ # perl5 prints: Can't find string terminator "'" anywhere before EOF
+
+You can avoid this problem, and remain compatible with perl4, if you
+always explicitly include the package name:
+
+ $x = 10;
+ print "x=${main'x}\n";
+
+Also see precedence traps, for parsing C<$:>.
+
+=item * 2nd and 3rd args to C<splice()> are now in scalar context
+
+The second and third arguments of C<splice()> are now evaluated in scalar
+context (as the Camel says) rather than list context.
+
+ sub sub1{return(0,2) } # return a 2-element list
+ sub sub2{ return(1,2,3)} # return a 3-element list
+ @a1 = ("a","b","c","d","e");
+ @a2 = splice(@a1,&sub1,&sub2);
+ print join(' ',@a2),"\n";
+
+ # perl4 prints: a b
+ # perl5 prints: c d e
+
+=item * Can't do C<goto> into a block that is optimized away
+
+You can't do a C<goto> into a block that is optimized away. Darn.
+
+ goto marker1;
+
+ for(1){
+ marker1:
+ print "Here I is!\n";
+ }
+
+ # perl4 prints: Here I is!
+ # perl5 errors: Can't "goto" into the middle of a foreach loop
+
+=item * Can't use whitespace as variable name or quote delimiter
+
+It is no longer syntactically legal to use whitespace as the name
+of a variable, or as a delimiter for any kind of quote construct.
+Double darn.
+
+ $a = ("foo bar");
+ $b = q baz;
+ print "a is $a, b is $b\n";
+
+ # perl4 prints: a is foo bar, b is baz
+ # perl5 errors: Bareword found where operator expected
+
+=item * C<while/if BLOCK BLOCK> gone
+
+The archaic while/if BLOCK BLOCK syntax is no longer supported.
+
+ if { 1 } {
+ print "True!";
+ }
+ else {
+ print "False!";
+ }
+
+ # perl4 prints: True!
+ # perl5 errors: syntax error at test.pl line 1, near "if {"
+
+=item * C<**> binds tighter than unary minus
+
+The C<**> operator now binds more tightly than unary minus.
+It was documented to work this way before, but didn't.
+
+ print -4**2,"\n";
+
+ # perl4 prints: 16
+ # perl5 prints: -16
+
+=item * C<foreach> changed when iterating over a list
+
+The meaning of C<foreach{}> has changed slightly when it is iterating over a
+list which is not an array. This used to assign the list to a
+temporary array, but no longer does so (for efficiency). This means
+that you'll now be iterating over the actual values, not over copies of
+the values. Modifications to the loop variable can change the original
+values.
+
+ @list = ('ab','abc','bcd','def');
+ foreach $var (grep(/ab/,@list)){
+ $var = 1;
+ }
+ print (join(':',@list));
+
+ # perl4 prints: ab:abc:bcd:def
+ # perl5 prints: 1:1:bcd:def
+
+To retain Perl4 semantics you need to assign your list
+explicitly to a temporary array and then iterate over that. For
+example, you might need to change
+
+ foreach $var (grep(/ab/,@list)){
+
+to
+
+ foreach $var (@tmp = grep(/ab/,@list)){
+
+Otherwise changing $var will clobber the values of @list. (This most often
+happens when you use C<$_> for the loop variable, and call subroutines in
+the loop that don't properly localize C<$_>.)
+
+=item * C<split> with no args behavior changed
+
+C<split> with no arguments now behaves like C<split ' '> (which doesn't
+return an initial null field if $_ starts with whitespace), it used to
+behave like C<split /\s+/> (which does).
+
+ $_ = ' hi mom';
+ print join(':', split);
+
+ # perl4 prints: :hi:mom
+ # perl5 prints: hi:mom
+
+=item * B<-e> behavior fixed
+
+Perl 4 would ignore any text which was attached to an B<-e> switch,
+always taking the code snippet from the following arg. Additionally, it
+would silently accept an B<-e> switch without a following arg. Both of
+these behaviors have been fixed.
+
+ perl -e'print "attached to -e"' 'print "separate arg"'
+
+ # perl4 prints: separate arg
+ # perl5 prints: attached to -e
+
+ perl -e
+
+ # perl4 prints:
+ # perl5 dies: No code specified for -e.
+
+=item * C<push> returns number of elements in resulting list
+
+In Perl 4 the return value of C<push> was undocumented, but it was
+actually the last value being pushed onto the target list. In Perl 5
+the return value of C<push> is documented, but has changed, it is the
+number of elements in the resulting list.
+
+ @x = ('existing');
+ print push(@x, 'first new', 'second new');
+
+ # perl4 prints: second new
+ # perl5 prints: 3
+
+=item * Some error messages differ
+
+Some error messages will be different.
+
+=item * C<split()> honors subroutine args
+
+In Perl 4, if in list context the delimiters to the first argument of
+C<split()> were C<??>, the result would be placed in C<@_> as well as
+being returned. Perl 5 has more respect for your subroutine arguments.
+
+=item * Bugs removed
+
+Some bugs may have been inadvertently removed. :-)
+
+=back
+
+=head2 Parsing Traps
+
+Perl4-to-Perl5 traps from having to do with parsing.
+
+=over 4
+
+=item * Space between . and = triggers syntax error
+
+Note the space between . and =
+
+ $string . = "more string";
+ print $string;
+
+ # perl4 prints: more string
+ # perl5 prints: syntax error at - line 1, near ". ="
+
+=item * Better parsing in perl 5
+
+Better parsing in perl 5
+
+ sub foo {}
+ &foo
+ print("hello, world\n");
+
+ # perl4 prints: hello, world
+ # perl5 prints: syntax error
+
+=item * Function parsing
+
+"if it looks like a function, it is a function" rule.
+
+ print
+ ($foo == 1) ? "is one\n" : "is zero\n";
+
+ # perl4 prints: is zero
+ # perl5 warns: "Useless use of a constant in void context" if using -w
+
+=item * String interpolation of C<$#array> differs
+
+String interpolation of the C<$#array> construct differs when braces
+are to used around the name.
+
+ @a = (1..3);
+ print "${#a}";
+
+ # perl4 prints: 2
+ # perl5 fails with syntax error
+
+ @ = (1..3);
+ print "$#{a}";
+
+ # perl4 prints: {a}
+ # perl5 prints: 2
+
+=item * Perl guesses on C<map>, C<grep> followed by C<{> if it starts BLOCK or hash ref
+
+When perl sees C<map {> (or C<grep {>), it has to guess whether the C<{>
+starts a BLOCK or a hash reference. If it guesses wrong, it will report
+a syntax error near the C<}> and the missing (or unexpected) comma.
+
+Use unary C<+> before C<{> on a hash reference, and unary C<+> applied
+to the first thing in a BLOCK (after C<{>), for perl to guess right all
+the time. (See L<perlfunc/map>.)
+
+=back
+
+=head2 Numerical Traps
+
+Perl4-to-Perl5 traps having to do with numerical operators,
+operands, or output from same.
+
+=over 5
+
+=item * Formatted output and significant digits
+
+Formatted output and significant digits. In general, Perl 5
+tries to be more precise. For example, on a Solaris Sparc:
+
+ print 7.373504 - 0, "\n";
+ printf "%20.18f\n", 7.373504 - 0;
+
+ # Perl4 prints:
+ 7.3750399999999996141
+ 7.375039999999999614
+
+ # Perl5 prints:
+ 7.373504
+ 7.375039999999999614
+
+Notice how the first result looks better in Perl 5.
+
+Your results may vary, since your floating point formatting routines
+and even floating point format may be slightly different.
+
+=item * Auto-increment operator over signed int limit deleted
+
+This specific item has been deleted. It demonstrated how the auto-increment
+operator would not catch when a number went over the signed int limit. Fixed
+in version 5.003_04. But always be wary when using large integers.
+If in doubt:
+
+ use Math::BigInt;
+
+=item * Assignment of return values from numeric equality tests doesn't work
+
+Assignment of return values from numeric equality tests
+does not work in perl5 when the test evaluates to false (0).
+Logical tests now return a null, instead of 0
+
+ $p = ($test == 1);
+ print $p,"\n";
+
+ # perl4 prints: 0
+ # perl5 prints:
+
+Also see L<"General Regular Expression Traps using s///, etc.">
+for another example of this new feature...
+
+=item * Bitwise string ops
+
+When bitwise operators which can operate upon either numbers or
+strings (C<& | ^ ~>) are given only strings as arguments, perl4 would
+treat the operands as bitstrings so long as the program contained a call
+to the C<vec()> function. perl5 treats the string operands as bitstrings.
+(See L<perlop/Bitwise String Operators> for more details.)
+
+ $fred = "10";
+ $barney = "12";
+ $betty = $fred & $barney;
+ print "$betty\n";
+ # Uncomment the next line to change perl4's behavior
+ # ($dummy) = vec("dummy", 0, 0);
+
+ # Perl4 prints:
+ 8
+
+ # Perl5 prints:
+ 10
+
+ # If vec() is used anywhere in the program, both print:
+ 10
+
+=back
+
+=head2 General data type traps
+
+Perl4-to-Perl5 traps involving most data-types, and their usage
+within certain expressions and/or context.
+
+=over 5
+
+=item * Negative array subscripts now count from the end of array
+
+Negative array subscripts now count from the end of the array.
+
+ @a = (1, 2, 3, 4, 5);
+ print "The third element of the array is $a[3] also expressed as $a[-2] \n";
+
+ # perl4 prints: The third element of the array is 4 also expressed as
+ # perl5 prints: The third element of the array is 4 also expressed as 4
+
+=item * Setting C<$#array> lower now discards array elements
+
+Setting C<$#array> lower now discards array elements, and makes them
+impossible to recover.
+
+ @a = (a,b,c,d,e);
+ print "Before: ",join('',@a);
+ $#a =1;
+ print ", After: ",join('',@a);
+ $#a =3;
+ print ", Recovered: ",join('',@a),"\n";
+
+ # perl4 prints: Before: abcde, After: ab, Recovered: abcd
+ # perl5 prints: Before: abcde, After: ab, Recovered: ab
+
+=item * Hashes get defined before use
+
+Hashes get defined before use
+
+ local($s,@a,%h);
+ die "scalar \$s defined" if defined($s);
+ die "array \@a defined" if defined(@a);
+ die "hash \%h defined" if defined(%h);
+
+ # perl4 prints:
+ # perl5 dies: hash %h defined
+
+Perl will now generate a warning when it sees defined(@a) and
+defined(%h).
+
+=item * Glob assignment from localized variable to variable
+
+glob assignment from variable to variable will fail if the assigned
+variable is localized subsequent to the assignment
+
+ @a = ("This is Perl 4");
+ *b = *a;
+ local(@a);
+ print @b,"\n";
+
+ # perl4 prints: This is Perl 4
+ # perl5 prints:
+
+=item * Assigning C<undef> to glob
+
+Assigning C<undef> to a glob has no effect in Perl 5. In Perl 4
+it undefines the associated scalar (but may have other side effects
+including SEGVs). Perl 5 will also warn if C<undef> is assigned to a
+typeglob. (Note that assigning C<undef> to a typeglob is different
+than calling the C<undef> function on a typeglob (C<undef *foo>), which
+has quite a few effects.
+
+ $foo = "bar";
+ *foo = undef;
+ print $foo;
+
+ # perl4 prints:
+ # perl4 warns: "Use of uninitialized variable" if using -w
+ # perl5 prints: bar
+ # perl5 warns: "Undefined value assigned to typeglob" if using -w
+
+=item * Changes in unary negation (of strings)
+
+Changes in unary negation (of strings)
+This change effects both the return value and what it
+does to auto(magic)increment.
+
+ $x = "aaa";
+ print ++$x," : ";
+ print -$x," : ";
+ print ++$x,"\n";
+
+ # perl4 prints: aab : -0 : 1
+ # perl5 prints: aab : -aab : aac
+
+=item * Modifying of constants prohibited
+
+perl 4 lets you modify constants:
+
+ $foo = "x";
+ &mod($foo);
+ for ($x = 0; $x < 3; $x++) {
+ &mod("a");
+ }
+ sub mod {
+ print "before: $_[0]";
+ $_[0] = "m";
+ print " after: $_[0]\n";
+ }
+
+ # perl4:
+ # before: x after: m
+ # before: a after: m
+ # before: m after: m
+ # before: m after: m
+
+ # Perl5:
+ # before: x after: m
+ # Modification of a read-only value attempted at foo.pl line 12.
+ # before: a
+
+=item * C<defined $var> behavior changed
+
+The behavior is slightly different for:
+
+ print "$x", defined $x
+
+ # perl 4: 1
+ # perl 5: <no output, $x is not called into existence>
+
+=item * Variable Suicide
+
+Variable suicide behavior is more consistent under Perl 5.
+Perl5 exhibits the same behavior for hashes and scalars,
+that perl4 exhibits for only scalars.
+
+ $aGlobal{ "aKey" } = "global value";
+ print "MAIN:", $aGlobal{"aKey"}, "\n";
+ $GlobalLevel = 0;
+ &test( *aGlobal );
+
+ sub test {
+ local( *theArgument ) = @_;
+ local( %aNewLocal ); # perl 4 != 5.001l,m
+ $aNewLocal{"aKey"} = "this should never appear";
+ print "SUB: ", $theArgument{"aKey"}, "\n";
+ $aNewLocal{"aKey"} = "level $GlobalLevel"; # what should print
+ $GlobalLevel++;
+ if( $GlobalLevel<4 ) {
+ &test( *aNewLocal );
+ }
+ }
+
+ # Perl4:
+ # MAIN:global value
+ # SUB: global value
+ # SUB: level 0
+ # SUB: level 1
+ # SUB: level 2
+
+ # Perl5:
+ # MAIN:global value
+ # SUB: global value
+ # SUB: this should never appear
+ # SUB: this should never appear
+ # SUB: this should never appear
+
+=back
+
+=head2 Context Traps - scalar, list contexts
+
+=over 5
+
+=item * Elements of argument lists for formats evaluated in list context
+
+The elements of argument lists for formats are now evaluated in list
+context. This means you can interpolate list values now.
+
+ @fmt = ("foo","bar","baz");
+ format STDOUT=
+ @<<<<< @||||| @>>>>>
+ @fmt;
+ .
+ write;
+
+ # perl4 errors: Please use commas to separate fields in file
+ # perl5 prints: foo bar baz
+
+=item * C<caller()> returns false value in scalar context if no caller present
+
+The C<caller()> function now returns a false value in a scalar context
+if there is no caller. This lets library files determine if they're
+being required.
+
+ caller() ? (print "You rang?\n") : (print "Got a 0\n");
+
+ # perl4 errors: There is no caller
+ # perl5 prints: Got a 0
+
+=item * Comma operator in scalar context gives scalar context to args
+
+The comma operator in a scalar context is now guaranteed to give a
+scalar context to its arguments.
+
+ @y= ('a','b','c');
+ $x = (1, 2, @y);
+ print "x = $x\n";
+
+ # Perl4 prints: x = c # Thinks list context interpolates list
+ # Perl5 prints: x = 3 # Knows scalar uses length of list
+
+=item * C<sprintf()> prototyped as C<($;@)>
+
+C<sprintf()> is prototyped as ($;@), so its first argument is given scalar
+context. Thus, if passed an array, it will probably not do what you want,
+unlike Perl 4:
+
+ @z = ('%s%s', 'foo', 'bar');
+ $x = sprintf(@z);
+ print $x;
+
+ # perl4 prints: foobar
+ # perl5 prints: 3
+
+C<printf()> works the same as it did in Perl 4, though:
+
+ @z = ('%s%s', 'foo', 'bar');
+ printf STDOUT (@z);
+
+ # perl4 prints: foobar
+ # perl5 prints: foobar
+
+=back
+
+=head2 Precedence Traps
+
+Perl4-to-Perl5 traps involving precedence order.
+
+Perl 4 has almost the same precedence rules as Perl 5 for the operators
+that they both have. Perl 4 however, seems to have had some
+inconsistencies that made the behavior differ from what was documented.
+
+=over 5
+
+=item * LHS vs. RHS of any assignment operator
+
+LHS vs. RHS of any assignment operator. LHS is evaluated first
+in perl4, second in perl5; this can affect the relationship
+between side-effects in sub-expressions.
+
+ @arr = ( 'left', 'right' );
+ $a{shift @arr} = shift @arr;
+ print join( ' ', keys %a );
+
+ # perl4 prints: left
+ # perl5 prints: right
+
+=item * Semantic errors introduced due to precedence
+
+These are now semantic errors because of precedence:
+
+ @list = (1,2,3,4,5);
+ %map = ("a",1,"b",2,"c",3,"d",4);
+ $n = shift @list + 2; # first item in list plus 2
+ print "n is $n, ";
+ $m = keys %map + 2; # number of items in hash plus 2
+ print "m is $m\n";
+
+ # perl4 prints: n is 3, m is 6
+ # perl5 errors and fails to compile
+
+=item * Precedence of assignment operators same as the precedence of assignment
+
+The precedence of assignment operators is now the same as the precedence
+of assignment. Perl 4 mistakenly gave them the precedence of the associated
+operator. So you now must parenthesize them in expressions like
+
+ /foo/ ? ($a += 2) : ($a -= 2);
+
+Otherwise
+
+ /foo/ ? $a += 2 : $a -= 2
+
+would be erroneously parsed as
+
+ (/foo/ ? $a += 2 : $a) -= 2;
+
+On the other hand,
+
+ $a += /foo/ ? 1 : 2;
+
+now works as a C programmer would expect.
+
+=item * C<open> requires parentheses around filehandle
+
+ open FOO || die;
+
+is now incorrect. You need parentheses around the filehandle.
+Otherwise, perl5 leaves the statement as its default precedence:
+
+ open(FOO || die);
+
+ # perl4 opens or dies
+ # perl5 opens FOO, dying only if 'FOO' is false, i.e. never
+
+=item * C<$:> precedence over C<$::> gone
+
+perl4 gives the special variable, C<$:> precedence, where perl5
+treats C<$::> as main C<package>
+
+ $a = "x"; print "$::a";
+
+ # perl 4 prints: -:a
+ # perl 5 prints: x
+
+=item * Precedence of file test operators documented
+
+perl4 had buggy precedence for the file test operators vis-a-vis
+the assignment operators. Thus, although the precedence table
+for perl4 leads one to believe C<-e $foo .= "q"> should parse as
+C<((-e $foo) .= "q")>, it actually parses as C<(-e ($foo .= "q"))>.
+In perl5, the precedence is as documented.
+
+ -e $foo .= "q"
+
+ # perl4 prints: no output
+ # perl5 prints: Can't modify -e in concatenation
+
+=item * C<keys>, C<each>, C<values> are regular named unary operators
+
+In perl4, keys(), each() and values() were special high-precedence operators
+that operated on a single hash, but in perl5, they are regular named unary
+operators. As documented, named unary operators have lower precedence
+than the arithmetic and concatenation operators C<+ - .>, but the perl4
+variants of these operators actually bind tighter than C<+ - .>.
+Thus, for:
+
+ %foo = 1..10;
+ print keys %foo - 1
+
+ # perl4 prints: 4
+ # perl5 prints: Type of arg 1 to keys must be hash (not subtraction)
+
+The perl4 behavior was probably more useful, if less consistent.
+
+=back
+
+=head2 General Regular Expression Traps using s///, etc.
+
+All types of RE traps.
+
+=over 5
+
+=item * C<s'$lhs'$rhs'> interpolates on either side
+
+C<s'$lhs'$rhs'> now does no interpolation on either side. It used to
+interpolate $lhs but not $rhs. (And still does not match a literal
+'$' in string)
+
+ $a=1;$b=2;
+ $string = '1 2 $a $b';
+ $string =~ s'$a'$b';
+ print $string,"\n";
+
+ # perl4 prints: $b 2 $a $b
+ # perl5 prints: 1 2 $a $b
+
+=item * C<m//g> attaches its state to the searched string
+
+C<m//g> now attaches its state to the searched string rather than the
+regular expression. (Once the scope of a block is left for the sub, the
+state of the searched string is lost)
+
+ $_ = "ababab";
+ while(m/ab/g){
+ &doit("blah");
+ }
+ sub doit{local($_) = shift; print "Got $_ "}
+
+ # perl4 prints: Got blah Got blah Got blah Got blah
+ # perl5 prints: infinite loop blah...
+
+=item * C<m//o> used within an anonymous sub
+
+Currently, if you use the C<m//o> qualifier on a regular expression
+within an anonymous sub, I<all> closures generated from that anonymous
+sub will use the regular expression as it was compiled when it was used
+the very first time in any such closure. For instance, if you say
+
+ sub build_match {
+ my($left,$right) = @_;
+ return sub { $_[0] =~ /$left stuff $right/o; };
+ }
+ $good = build_match('foo','bar');
+ $bad = build_match('baz','blarch');
+ print $good->('foo stuff bar') ? "ok\n" : "not ok\n";
+ print $bad->('baz stuff blarch') ? "ok\n" : "not ok\n";
+ print $bad->('foo stuff bar') ? "not ok\n" : "ok\n";
+
+For most builds of Perl5, this will print:
+ok
+not ok
+not ok
+
+build_match() will always return a sub which matches the contents of
+$left and $right as they were the I<first> time that build_match()
+was called, not as they are in the current call.
+
+=item * C<$+> isn't set to whole match
+
+If no parentheses are used in a match, Perl4 sets C<$+> to
+the whole match, just like C<$&>. Perl5 does not.
+
+ "abcdef" =~ /b.*e/;
+ print "\$+ = $+\n";
+
+ # perl4 prints: bcde
+ # perl5 prints:
+
+=item * Substitution now returns null string if it fails
+
+substitution now returns the null string if it fails
+
+ $string = "test";
+ $value = ($string =~ s/foo//);
+ print $value, "\n";
+
+ # perl4 prints: 0
+ # perl5 prints:
+
+Also see L<Numerical Traps> for another example of this new feature.
+
+=item * C<s`lhs`rhs`> is now a normal substitution
+
+C<s`lhs`rhs`> (using backticks) is now a normal substitution, with no
+backtick expansion
+
+ $string = "";
+ $string =~ s`^`hostname`;
+ print $string, "\n";
+
+ # perl4 prints: <the local hostname>
+ # perl5 prints: hostname
+
+=item * Stricter parsing of variables in regular expressions
+
+Stricter parsing of variables used in regular expressions
+
+ s/^([^$grpc]*$grpc[$opt$plus$rep]?)//o;
+
+ # perl4: compiles w/o error
+ # perl5: with Scalar found where operator expected ..., near "$opt$plus"
+
+an added component of this example, apparently from the same script, is
+the actual value of the s'd string after the substitution.
+C<[$opt]> is a character class in perl4 and an array subscript in perl5
+
+ $grpc = 'a';
+ $opt = 'r';
+ $_ = 'bar';
+ s/^([^$grpc]*$grpc[$opt]?)/foo/;
+ print;
+
+ # perl4 prints: foo
+ # perl5 prints: foobar
+
+=item * C<m?x?> matches only once
+
+Under perl5, C<m?x?> matches only once, like C<?x?>. Under perl4, it matched
+repeatedly, like C</x/> or C<m!x!>.
+
+ $test = "once";
+ sub match { $test =~ m?once?; }
+ &match();
+ if( &match() ) {
+ # m?x? matches more then once
+ print "perl4\n";
+ } else {
+ # m?x? matches only once
+ print "perl5\n";
+ }
+
+ # perl4 prints: perl4
+ # perl5 prints: perl5
+
+=item * Failed matches don't reset the match variables
+
+Unlike in Ruby, failed matches in Perl do not reset the match variables
+($1, $2, ..., C<$`>, ...).
+
+=back
+
+=head2 Subroutine, Signal, Sorting Traps
+
+The general group of Perl4-to-Perl5 traps having to do with
+Signals, Sorting, and their related subroutines, as well as
+general subroutine traps. Includes some OS-Specific traps.
+
+=over 5
+
+=item * Barewords that used to look like strings look like subroutine calls
+
+Barewords that used to look like strings to Perl will now look like subroutine
+calls if a subroutine by that name is defined before the compiler sees them.
+
+ sub SeeYa { warn"Hasta la vista, baby!" }
+ $SIG{'TERM'} = SeeYa;
+ print "SIGTERM is now $SIG{'TERM'}\n";
+
+ # perl4 prints: SIGTERM is now main'SeeYa
+ # perl5 prints: SIGTERM is now main::1 (and warns "Hasta la vista, baby!")
+
+Use B<-w> to catch this one
+
+=item * Reverse is no longer allowed as the name of a sort subroutine
+
+reverse is no longer allowed as the name of a sort subroutine.
+
+ sub reverse{ print "yup "; $a <=> $b }
+ print sort reverse (2,1,3);
+
+ # perl4 prints: yup yup 123
+ # perl5 prints: 123
+ # perl5 warns (if using -w): Ambiguous call resolved as CORE::reverse()
+
+=item * C<warn()> won't let you specify a filehandle.
+
+Although it _always_ printed to STDERR, warn() would let you specify a
+filehandle in perl4. With perl5 it does not.
+
+ warn STDERR "Foo!";
+
+ # perl4 prints: Foo!
+ # perl5 prints: String found where operator expected
+
+=back
+
+=head2 OS Traps
+
+=over 5
+
+=item * SysV resets signal handler correctly
+
+Under HPUX, and some other SysV OSes, one had to reset any signal handler,
+within the signal handler function, each time a signal was handled with
+perl4. With perl5, the reset is now done correctly. Any code relying
+on the handler _not_ being reset will have to be reworked.
+
+Since version 5.002, Perl uses sigaction() under SysV.
+
+ sub gotit {
+ print "Got @_... ";
+ }
+ $SIG{'INT'} = 'gotit';
+
+ $| = 1;
+ $pid = fork;
+ if ($pid) {
+ kill('INT', $pid);
+ sleep(1);
+ kill('INT', $pid);
+ } else {
+ while (1) {sleep(10);}
+ }
+
+ # perl4 (HPUX) prints: Got INT...
+ # perl5 (HPUX) prints: Got INT... Got INT...
+
+=item * SysV C<seek()> appends correctly
+
+Under SysV OSes, C<seek()> on a file opened to append C<<< >> >>> now does
+the right thing w.r.t. the fopen() manpage. e.g., - When a file is opened
+for append, it is impossible to overwrite information already in
+the file.
+
+ open(TEST,">>seek.test");
+ $start = tell TEST;
+ foreach(1 .. 9){
+ print TEST "$_ ";
+ }
+ $end = tell TEST;
+ seek(TEST,$start,0);
+ print TEST "18 characters here";
+
+ # perl4 (solaris) seek.test has: 18 characters here
+ # perl5 (solaris) seek.test has: 1 2 3 4 5 6 7 8 9 18 characters here
+
+
+
+=back
+
+=head2 Interpolation Traps
+
+Perl4-to-Perl5 traps having to do with how things get interpolated
+within certain expressions, statements, contexts, or whatever.
+
+=over 5
+
+=item * C<@> always interpolates an array in double-quotish strings
+
+@ now always interpolates an array in double-quotish strings.
+
+ print "To: someone@somewhere.com\n";
+
+ # perl4 prints: To:someone@somewhere.com
+ # perl < 5.6.1, error : In string, @somewhere now must be written as \@somewhere
+ # perl >= 5.6.1, warning : Possible unintended interpolation of @somewhere in string
+
+=item * Double-quoted strings may no longer end with an unescaped $
+
+Double-quoted strings may no longer end with an unescaped $.
+
+ $foo = "foo$";
+ print "foo is $foo\n";
+
+ # perl4 prints: foo is foo$
+ # perl5 errors: Final $ should be \$ or $name
+
+Note: perl5 DOES NOT error on the terminating @ in $bar
+
+=item * Arbitrary expressions are evaluated inside braces within double quotes
+
+Perl now sometimes evaluates arbitrary expressions inside braces that occur
+within double quotes (usually when the opening brace is preceded by C<$>
+or C<@>).
+
+ @www = "buz";
+ $foo = "foo";
+ $bar = "bar";
+ sub foo { return "bar" };
+ print "|@{w.w.w}|${main'foo}|";
+
+ # perl4 prints: |@{w.w.w}|foo|
+ # perl5 prints: |buz|bar|
+
+Note that you can C<use strict;> to ward off such trappiness under perl5.
+
+=item * C<$$x> now tries to dereference $x
+
+The construct "this is $$x" used to interpolate the pid at that point, but
+now tries to dereference $x. C<$$> by itself still works fine, however.
+
+ $s = "a reference";
+ $x = *s;
+ print "this is $$x\n";
+
+ # perl4 prints: this is XXXx (XXX is the current pid)
+ # perl5 prints: this is a reference
+
+=item * Creation of hashes on the fly with C<eval "EXPR"> requires protection
+
+Creation of hashes on the fly with C<eval "EXPR"> now requires either both
+C<$>'s to be protected in the specification of the hash name, or both curlies
+to be protected. If both curlies are protected, the result will be compatible
+with perl4 and perl5. This is a very common practice, and should be changed
+to use the block form of C<eval{}> if possible.
+
+ $hashname = "foobar";
+ $key = "baz";
+ $value = 1234;
+ eval "\$$hashname{'$key'} = q|$value|";
+ (defined($foobar{'baz'})) ? (print "Yup") : (print "Nope");
+
+ # perl4 prints: Yup
+ # perl5 prints: Nope
+
+Changing
+
+ eval "\$$hashname{'$key'} = q|$value|";
+
+to
+
+ eval "\$\$hashname{'$key'} = q|$value|";
+
+causes the following result:
+
+ # perl4 prints: Nope
+ # perl5 prints: Yup
+
+or, changing to
+
+ eval "\$$hashname\{'$key'\} = q|$value|";
+
+causes the following result:
+
+ # perl4 prints: Yup
+ # perl5 prints: Yup
+ # and is compatible for both versions
+
+
+=item * Bugs in earlier perl versions
+
+perl4 programs which unconsciously rely on the bugs in earlier perl versions.
+
+ perl -e '$bar=q/not/; print "This is $foo{$bar} perl5"'
+
+ # perl4 prints: This is not perl5
+ # perl5 prints: This is perl5
+
+=item * Array and hash brackets during interpolation
+
+You also have to be careful about array and hash brackets during
+interpolation.
+
+ print "$foo["
+
+ perl 4 prints: [
+ perl 5 prints: syntax error
+
+ print "$foo{"
+
+ perl 4 prints: {
+ perl 5 prints: syntax error
+
+Perl 5 is expecting to find an index or key name following the respective
+brackets, as well as an ending bracket of the appropriate type. In order
+to mimic the behavior of Perl 4, you must escape the bracket like so.
+
+ print "$foo\[";
+ print "$foo\{";
+
+=item * Interpolation of C<\$$foo{bar}>
+
+Similarly, watch out for: C<\$$foo{bar}>
+
+ $foo = "baz";
+ print "\$$foo{bar}\n";
+
+ # perl4 prints: $baz{bar}
+ # perl5 prints: $
+
+Perl 5 is looking for C<$foo{bar}> which doesn't exist, but perl 4 is
+happy just to expand $foo to "baz" by itself. Watch out for this
+especially in C<eval>'s.
+
+=item * C<qq()> string passed to C<eval> will not find string terminator
+
+C<qq()> string passed to C<eval>
+
+ eval qq(
+ foreach \$y (keys %\$x\) {
+ \$count++;
+ }
+ );
+
+ # perl4 runs this ok
+ # perl5 prints: Can't find string terminator ")"
+
+=back
+
+=head2 DBM Traps
+
+General DBM traps.
+
+=over 5
+
+=item * Perl5 must have been linked with same dbm/ndbm as the default for C<dbmopen()>
+
+Existing dbm databases created under perl4 (or any other dbm/ndbm tool)
+may cause the same script, run under perl5, to fail. The build of perl5
+must have been linked with the same dbm/ndbm as the default for C<dbmopen()>
+to function properly without C<tie>'ing to an extension dbm implementation.
+
+ dbmopen (%dbm, "file", undef);
+ print "ok\n";
+
+ # perl4 prints: ok
+ # perl5 prints: ok (IFF linked with -ldbm or -lndbm)
+
+
+=item * DBM exceeding limit on the key/value size will cause perl5 to exit immediately
+
+Existing dbm databases created under perl4 (or any other dbm/ndbm tool)
+may cause the same script, run under perl5, to fail. The error generated
+when exceeding the limit on the key/value size will cause perl5 to exit
+immediately.
+
+ dbmopen(DB, "testdb",0600) || die "couldn't open db! $!";
+ $DB{'trap'} = "x" x 1024; # value too large for most dbm/ndbm
+ print "YUP\n";
+
+ # perl4 prints:
+ dbm store returned -1, errno 28, key "trap" at - line 3.
+ YUP
+
+ # perl5 prints:
+ dbm store returned -1, errno 28, key "trap" at - line 3.
+
+=back
+
+=head2 Unclassified Traps
+
+Everything else.
+
+=over 5
+
+=item * C<require>/C<do> trap using returned value
+
+If the file doit.pl has:
+
+ sub foo {
+ $rc = do "./do.pl";
+ return 8;
+ }
+ print &foo, "\n";
+
+And the do.pl file has the following single line:
+
+ return 3;
+
+Running doit.pl gives the following:
+
+ # perl 4 prints: 3 (aborts the subroutine early)
+ # perl 5 prints: 8
+
+Same behavior if you replace C<do> with C<require>.
+
+=item * C<split> on empty string with LIMIT specified
+
+ $string = '';
+ @list = split(/foo/, $string, 2)
+
+Perl4 returns a one element list containing the empty string but Perl5
+returns an empty list.
+
+=back
+
+As always, if any of these are ever officially declared as bugs,
+they'll be fixed and removed.
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perltru64.pod b/Master/tlpkg/tlperl/lib/pods/perltru64.pod
new file mode 100644
index 00000000000..6961a0e7c17
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltru64.pod
@@ -0,0 +1,172 @@
+If you read this file _as_is_, just ignore the funny characters you see.
+It is written in the POD format (see pod/perlpod.pod) which is specially
+designed to be readable as is.
+
+=head1 NAME
+
+README.tru64 - Perl version 5 on Tru64 (formerly known as Digital UNIX formerly known as DEC OSF/1) systems
+
+=head1 DESCRIPTION
+
+This document describes various features of HP's (formerly Compaq's,
+formerly Digital's) Unix operating system (Tru64) that will affect
+how Perl version 5 (hereafter just Perl) is configured, compiled
+and/or runs.
+
+=head2 Compiling Perl 5 on Tru64
+
+The recommended compiler to use in Tru64 is the native C compiler.
+The native compiler produces much faster code (the speed difference is
+noticeable: several dozen percentages) and also more correct code: if
+you are considering using the GNU C compiler you should use at the
+very least the release of 2.95.3 since all older gcc releases are
+known to produce broken code when compiling Perl. One manifestation
+of this brokenness is the lib/sdbm test dumping core; another is many
+of the op/regexp and op/pat, or ext/Storable tests dumping core
+(the exact pattern of failures depending on the GCC release and
+optimization flags).
+
+gcc 3.2.1 is known to work okay with Perl 5.8.0. However, when
+optimizing the toke.c gcc likes to have a lot of memory, 256 megabytes
+seems to be enough. The default setting of the process data section
+in Tru64 should be one gigabyte, but some sites/setups might have
+lowered that. The configuration process of Perl checks for too low
+process limits, and lowers the optimization for the toke.c if
+necessary, and also gives advice on how to raise the process limits.
+
+Also, Configure might abort with
+
+ Build a threading Perl? [n]
+ Configure[2437]: Syntax error at line 1 : `config.sh' is not expected.
+
+This indicates that Configure is being run with a broken Korn shell
+(even though you think you are using a Bourne shell by using
+"sh Configure" or "./Configure"). The Korn shell bug has been reported
+to Compaq as of February 1999 but in the meanwhile, the reason ksh is
+being used is that you have the environment variable BIN_SH set to
+'xpg4'. This causes /bin/sh to delegate its duties to /bin/posix/sh
+(a ksh). Unset the environment variable and rerun Configure.
+
+=head2 Using Large Files with Perl on Tru64
+
+In Tru64 Perl is automatically able to use large files, that is,
+files larger than 2 gigabytes, there is no need to use the Configure
+-Duselargefiles option as described in INSTALL (though using the option
+is harmless).
+
+=head2 Threaded Perl on Tru64
+
+If you want to use threads, you should primarily use the Perl
+5.8.0 threads model by running Configure with -Duseithreads.
+
+Perl threading is going to work only in Tru64 4.0 and newer releases,
+older operating releases like 3.2 aren't probably going to work
+properly with threads.
+
+In Tru64 V5 (at least V5.1A, V5.1B) you cannot build threaded Perl with gcc
+because the system header <pthread.h> explicitly checks for supported
+C compilers, gcc (at least 3.2.2) not being one of them. But the
+system C compiler should work just fine.
+
+=head2 Long Doubles on Tru64
+
+You cannot Configure Perl to use long doubles unless you have at least
+Tru64 V5.0, the long double support simply wasn't functional enough
+before that. Perl's Configure will override attempts to use the long
+doubles (you can notice this by Configure finding out that the modfl()
+function does not work as it should).
+
+At the time of this writing (June 2002), there is a known bug in the
+Tru64 libc printing of long doubles when not using "e" notation.
+The values are correct and usable, but you only get a limited number
+of digits displayed unless you force the issue by using C<printf
+"%.33e",$num> or the like. For Tru64 versions V5.0A through V5.1A, a
+patch is expected sometime after perl 5.8.0 is released. If your libc
+has not yet been patched, you'll get a warning from Configure when
+selecting long doubles.
+
+=head2 DB_File tests failing on Tru64
+
+The DB_File tests (db-btree.t, db-hash.t, db-recno.t) may fail you
+have installed a newer version of Berkeley DB into the system and the
+-I and -L compiler and linker flags introduce version conflicts with
+the DB 1.85 headers and libraries that came with the Tru64. For example,
+mixing a DB v2 library with the DB v1 headers is a bad idea. Watch
+out for Configure options -Dlocincpth and -Dloclibpth, and check your
+/usr/local/include and /usr/local/lib since they are included by default.
+
+The second option is to explicitly instruct Configure to detect the
+newer Berkeley DB installation, by supplying the right directories with
+C<-Dlocincpth=/some/include> and C<-Dloclibpth=/some/lib> B<and> before
+running "make test" setting your LD_LIBRARY_PATH to F</some/lib>.
+
+The third option is to work around the problem by disabling the
+DB_File completely when build Perl by specifying -Ui_db to Configure,
+and then using the BerkeleyDB module from CPAN instead of DB_File.
+The BerkeleyDB works with Berkeley DB versions 2.* or greater.
+
+The Berkeley DB 4.1.25 has been tested with Tru64 V5.1A and found
+to work. The latest Berkeley DB can be found from F<http://www.sleepycat.com>.
+
+=head2 64-bit Perl on Tru64
+
+In Tru64 Perl's integers are automatically 64-bit wide, there is
+no need to use the Configure -Duse64bitint option as described
+in INSTALL. Similarly, there is no need for -Duse64bitall
+since pointers are automatically 64-bit wide.
+
+=head2 Warnings about floating-point overflow when compiling Perl on Tru64
+
+When compiling Perl in Tru64 you may (depending on the compiler
+release) see two warnings like this
+
+ cc: Warning: numeric.c, line 104: In this statement, floating-point overflow occurs in evaluating the expression "1.8e308". (floatoverfl)
+ return HUGE_VAL;
+ -----------^
+
+and when compiling the POSIX extension
+
+ cc: Warning: const-c.inc, line 2007: In this statement, floating-point overflow occurs in evaluating the expression "1.8e308". (floatoverfl)
+ return HUGE_VAL;
+ -------------------^
+
+The exact line numbers may vary between Perl releases. The warnings
+are benign and can be ignored: in later C compiler releases the warnings
+should be gone.
+
+When the file F<pp_sys.c> is being compiled you may (depending on the
+operating system release) see an additional compiler flag being used:
+C<-DNO_EFF_ONLY_OK>. This is normal and refers to a feature that is
+relevant only if you use the C<filetest> pragma. In older releases of
+the operating system the feature was broken and the NO_EFF_ONLY_OK
+instructs Perl not to use the feature.
+
+=head1 Testing Perl on Tru64
+
+During "make test" the C<comp/cpp> will be skipped because on Tru64 it
+cannot be tested before Perl has been installed. The test refers to
+the use of the C<-P> option of Perl.
+
+=head1 ext/ODBM_File/odbm Test Failing With Static Builds
+
+The ext/ODBM_File/odbm is known to fail with static builds
+(Configure -Uusedl) due to a known bug in Tru64's static libdbm
+library. The good news is that you very probably don't need to ever
+use the ODBM_File extension since more advanced NDBM_File works fine,
+not to mention the even more advanced DB_File.
+
+=head1 Perl Fails Because Of Unresolved Symbol sockatmark
+
+If you get an error like
+
+ Can't load '.../OSF1/lib/perl5/5.8.0/alpha-dec_osf/auto/IO/IO.so' for module IO: Unresolved symbol in .../lib/perl5/5.8.0/alpha-dec_osf/auto/IO/IO.so: sockatmark at .../lib/perl5/5.8.0/alpha-dec_osf/XSLoader.pm line 75.
+
+you need to either recompile your Perl in Tru64 4.0D or upgrade your
+Tru64 4.0D to at least 4.0F: the sockatmark() system call was
+added in Tru64 4.0F, and the IO extension refers that symbol.
+
+=head1 AUTHOR
+
+Jarkko Hietaniemi <jhi@iki.fi>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perltw.pod b/Master/tlpkg/tlperl/lib/pods/perltw.pod
new file mode 100644
index 00000000000..934db9eb42d
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perltw.pod
@@ -0,0 +1,172 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+The following documentation is written in Big5 encoding.
+
+¦pªG§A¥Î¤@¯ëªº¤å¦r½s¿è¾¹¾\Äý³o¥÷¤å¥ó, ½Ð©¿²¤¤å¤¤©_¯Sªºµù°O¦r²Å.
+³o¥÷¤å¥ó¬O¥H POD (²©ú¤å¥ó®æ¦¡) ¼g¦¨; ³oºØ®æ¦¡¬O¬°¤F¯àÅý¤Hª½±µÅª¨ú,
+¦Ó¯S§O³]­pªº. Ãö©ó¦¹®æ¦¡ªº¶i¤@¨B¸ê°T, ½Ð°Ñ¦Ò perlpod ½u¤W¤å¥ó.
+
+=encoding big5
+
+=head1 NAME
+
+perltw - ¥¿Å餤¤å Perl «ü«n
+
+=head1 DESCRIPTION
+
+Åwªï¨Ó¨ì Perl ªº¤Ñ¦a!
+
+±q 5.8.0 ª©¶}©l, Perl ¨ã³Æ¤F§¹µ½ªº Unicode (¸U°ê½X) ¤ä´©,
+¤]³s±a¤ä´©¤F³\¦h©Ô¤B»y¨t¥H¥~ªº½s½X¤è¦¡; CJK (¤¤¤éÁú) «K¬O¨ä¤¤ªº¤@³¡¥÷.
+Unicode ¬O°ê»Ú©Êªº¼Ð·Ç, ¸Õ¹Ï²[»\¥@¬É¤W©Ò¦³ªº¦r²Å: ¦è¤è¥@¬É, ªF¤è¥@¬É,
+¥H¤Î¨âªÌ¶¡ªº¤@¤Á (§Æþ¤å, ±Ô§Q¨È¤å, ªü©Ô§B¤å, §Æ§B¨Ó¤å, ¦L«×¤å,
+¦L¦a¦w¤å, µ¥µ¥). ¥¦¤]®e¯Ç¤F¦hºØ§@·~¨t²Î»P¥­»O (¦p PC ¤Î³Áª÷¶ð).
+
+Perl ¥»¨­¥H Unicode ¶i¦æ¾Þ§@. ³oªí¥Ü Perl ¤º³¡ªº¦r¦ê¸ê®Æ¥i¥Î Unicode
+ªí¥Ü; Perl ªº¨ç¦¡»Pºâ²Å (¨Ò¦p¥¿³Wªí¥Ü¦¡¤ñ¹ï) ¤]¯à¹ï Unicode ¶i¦æ¾Þ§@.
+¦b¿é¤J¤Î¿é¥X®É, ¬°¤F³B²z¥H Unicode ¤§«eªº½s½X¤è¦¡Àx¦sªº¸ê®Æ, Perl
+´£¨Ñ¤F Encode ³o­Ó¼Ò²Õ, ¥i¥HÅý§A»´©ö¦aŪ¨ú¤Î¼g¤J¦³ªº½s½X¸ê®Æ.
+
+Encode ©µ¦ù¼Ò²Õ¤ä´©¤U¦C¥¿Å餤¤åªº½s½X¤è¦¡ ('big5' ªí¥Ü 'big5-eten'):
+
+ big5-eten Big5 ½s½X (§t­Ê¤Ñ©µ¦ù¦r§Î)
+ big5-hkscs Big5 + ­»´ä¥~¦r¶°, 2001 ¦~ª©
+ cp950 ¦r½X­¶ 950 (Big5 + ·L³n²K¥[ªº¦r²Å)
+
+Á|¨Ò¨Ó»¡, ±N Big5 ½s½XªºÀÉ®×Âন Unicode, ¯­»ÝÁä¤J¤U¦C«ü¥O:
+
+ perl -Mencoding=big5,STDOUT,utf8 -pe1 < file.big5 > file.utf8
+
+Perl ¤]¤ºªþ¤F "piconv", ¤@¤ä§¹¥þ¥H Perl ¼g¦¨ªº¦r²ÅÂà´«¤u¨ãµ{¦¡, ¥Îªk¦p¤U:
+
+ piconv -f big5 -t utf8 < file.big5 > file.utf8
+ piconv -f utf8 -t big5 < file.utf8 > file.big5
+
+¥t¥~, §Q¥Î encoding ¼Ò²Õ, §A¥i¥H»´©ö¼g¥X¥H¦r²Å¬°³æ¦ìªºµ{¦¡½X, ¦p¤U©Ò¥Ü:
+
+ #!/usr/bin/env perl
+ # ±Ò°Ê big5 ¦r¦ê¸ÑªR; ¼Ð·Ç¿é¥X¤J¤Î¼Ð·Ç¿ù»~³£³]¬° big5 ½s½X
+ use encoding 'big5', STDIN => 'big5', STDOUT => 'big5';
+ print length("Àd¾m"); # 2 (Âù¤Þ¸¹ªí¥Ü¦r²Å)
+ print length('Àd¾m'); # 4 (³æ¤Þ¸¹ªí¥Ü¦ì¤¸²Õ)
+ print index("½Î½Î±Ð»£", "να"); # -1 (¤£¥]§t¦¹¤l¦r¦ê)
+ print index('½Î½Î±Ð»£', 'να'); # 1 (±q²Ä¤G­Ó¦ì¤¸²Õ¶}©l)
+
+¦b³Ì«á¤@¦C¨Ò¤l¸Ì, "½Î" ªº²Ä¤G­Ó¦ì¤¸²Õ»P "½Î" ªº²Ä¤@­Ó¦ì¤¸²Õµ²¦X¦¨ Big5
+½Xªº "ν"; "½Î" ªº²Ä¤G­Ó¦ì¤¸²Õ«h»P "±Ð" ªº²Ä¤@­Ó¦ì¤¸²Õµ²¦X¦¨ "α".
+³o¸Ñ¨M¤F¥H«e Big5 ½X¤ñ¹ï³B²z¤W±`¨£ªº°ÝÃD.
+
+=head2 ÃB¥~ªº¤¤¤å½s½X
+
+¦pªG»Ý­n§ó¦hªº¤¤¤å½s½X, ¥i¥H±q CPAN (L<http://www.cpan.org/>) ¤U¸ü
+Encode::HanExtra ¼Ò²Õ. ¥¦¥Ø«e´£¨Ñ¤U¦C½s½X¤è¦¡:
+
+ cccii 1980 ¦~¤å«Ø·|ªº¤¤¤å¸ê°T¥æ´«½X
+ euc-tw Unix ©µ¦ù¦r²Å¶°, ¥]§t CNS11643 ¥­­± 1-7
+ big5plus ¤¤¤å¼Æ¦ì¤Æ§Þ³N±À¼s°òª÷·|ªº Big5+
+ big5ext ¤¤¤å¼Æ¦ì¤Æ§Þ³N±À¼s°òª÷·|ªº Big5e
+
+¥t¥~, Encode::HanConvert ¼Ò²Õ«h´£¨Ñ¤F²ÁcÂà´«¥Îªº¨âºØ½s½X:
+
+ big5-simp Big5 ¥¿Å餤¤å»P Unicode ²Å餤¤å¤¬Âà
+ gbk-trad GBK ²Å餤¤å»P Unicode ¥¿Å餤¤å¤¬Âà
+
+­Y·Q¦b GBK »P Big5 ¤§¶¡¤¬Âà, ½Ð°Ñ¦Ò¸Ó¼Ò²Õ¤ºªþªº b2g.pl »P g2b.pl ¨â¤äµ{¦¡,
+©Î¦bµ{¦¡¤º¨Ï¥Î¤U¦C¼gªk:
+
+ use Encode::HanConvert;
+ $euc_cn = big5_to_gb($big5); # ±q Big5 Âର GBK
+ $big5 = gb_to_big5($euc_cn); # ±q GBK Âର Big5
+
+=head2 ¶i¤@¨Bªº¸ê°T
+
+½Ð°Ñ¦Ò Perl ¤ºªþªº¤j¶q»¡©ú¤å¥ó (¤£©¯¥þ¬O¥Î­^¤å¼gªº), ¨Ó¾Ç²ß§ó¦hÃö©ó
+Perl ªºª¾ÃÑ, ¥H¤Î Unicode ªº¨Ï¥Î¤è¦¡. ¤£¹L, ¥~³¡ªº¸ê·½¬Û·íÂ×´I:
+
+=head2 ´£¨Ñ Perl ¸ê·½ªººô§}
+
+=over 4
+
+=item L<http://www.perl.com/>
+
+Perl ªº­º­¶ (¥Ñ¼ÚµÜ§¤½¥qºûÅ@)
+
+=item L<http://www.cpan.org/>
+
+Perl ºî¦X¨åÂúô (Comprehensive Perl Archive Network)
+
+=item L<http://lists.perl.org/>
+
+Perl ¶l»¼½×¾Â¤@Äý
+
+=back
+
+=head2 ¾Ç²ß Perl ªººô§}
+
+=over 4
+
+=item L<http://www.oreilly.com.tw/product_perl.php?id=index_perl>
+
+¥¿Å餤¤åª©ªº¼ÚµÜ§ Perl ®ÑÂÇ
+
+=item L<http://groups.google.com/groups?q=tw.bbs.comp.lang.perl>
+
+»OÆW Perl ³s½u°Q½×°Ï (¤]´N¬O¦U¤j BBS ªº Perl ³s½uª©)
+
+=back
+
+=head2 Perl ¨Ï¥ÎªÌ¶°·|
+
+=over 4
+
+=item L<http://www.pm.org/groups/asia.html>
+
+»OÆW Perl ±À¼s²Õ¤@Äý
+
+=item L<http://irc.elixus.org/>
+
+ÃÀ¥ß¨ó½u¤W²á¤Ñ«Ç
+
+=back
+
+=head2 Unicode ¬ÛÃöºô§}
+
+=over 4
+
+=item L<http://www.unicode.org/>
+
+Unicode ¾Ç³N¾Ç·| (Unicode ¼Ð·Çªº¨î©wªÌ)
+
+=item L<http://www.cl.cam.ac.uk/%7Emgk25/unicode.html>
+
+Unix/Linux ¤Wªº UTF-8 ¤Î Unicode µª«È°Ý
+
+=back
+
+=head2 ¤¤¤å¤Æ¸ê°T
+
+=over 4
+
+=item ¤¤¤å¤Æ³nÅéÁp·ù
+
+L<http://www.cpatch.org/>
+
+=item Linux ³nÅ餤¤å¤Æ­p¹º
+
+L<http://www.linux.org.tw/CLDP/>
+
+=back
+
+=head1 SEE ALSO
+
+L<Encode>, L<Encode::TW>, L<encoding>, L<perluniintro>, L<perlunicode>
+
+=head1 AUTHORS
+
+Jarkko Hietaniemi E<lt>jhi@iki.fiE<gt>
+
+Audrey Tang (­ð»ñ) E<lt>audreyt@audreyt.orgE<gt>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlunicode.pod b/Master/tlpkg/tlperl/lib/pods/perlunicode.pod
new file mode 100644
index 00000000000..140d1340b20
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlunicode.pod
@@ -0,0 +1,1762 @@
+=head1 NAME
+
+perlunicode - Unicode support in Perl
+
+=head1 DESCRIPTION
+
+=head2 Important Caveats
+
+Unicode support is an extensive requirement. While Perl does not
+implement the Unicode standard or the accompanying technical reports
+from cover to cover, Perl does support many Unicode features.
+
+People who want to learn to use Unicode in Perl, should probably read
+the L<Perl Unicode tutorial, perlunitut|perlunitut>, before reading
+this reference document.
+
+Also, the use of Unicode may present security issues that aren't obvious.
+Read L<Unicode Security Considerations|http://www.unicode.org/reports/tr36>.
+
+=over 4
+
+=item Input and Output Layers
+
+Perl knows when a filehandle uses Perl's internal Unicode encodings
+(UTF-8, or UTF-EBCDIC if in EBCDIC) if the filehandle is opened with
+the ":utf8" layer. Other encodings can be converted to Perl's
+encoding on input or from Perl's encoding on output by use of the
+":encoding(...)" layer. See L<open>.
+
+To indicate that Perl source itself is in UTF-8, use C<use utf8;>.
+
+=item Regular Expressions
+
+The regular expression compiler produces polymorphic opcodes. That is,
+the pattern adapts to the data and automatically switches to the Unicode
+character scheme when presented with data that is internally encoded in
+UTF-8, or instead uses a traditional byte scheme when presented with
+byte data.
+
+=item C<use utf8> still needed to enable UTF-8/UTF-EBCDIC in scripts
+
+As a compatibility measure, the C<use utf8> pragma must be explicitly
+included to enable recognition of UTF-8 in the Perl scripts themselves
+(in string or regular expression literals, or in identifier names) on
+ASCII-based machines or to recognize UTF-EBCDIC on EBCDIC-based
+machines. B<These are the only times when an explicit C<use utf8>
+is needed.> See L<utf8>.
+
+=item BOM-marked scripts and UTF-16 scripts autodetected
+
+If a Perl script begins marked with the Unicode BOM (UTF-16LE, UTF16-BE,
+or UTF-8), or if the script looks like non-BOM-marked UTF-16 of either
+endianness, Perl will correctly read in the script as Unicode.
+(BOMless UTF-8 cannot be effectively recognized or differentiated from
+ISO 8859-1 or other eight-bit encodings.)
+
+=item C<use encoding> needed to upgrade non-Latin-1 byte strings
+
+By default, there is a fundamental asymmetry in Perl's Unicode model:
+implicit upgrading from byte strings to Unicode strings assumes that
+they were encoded in I<ISO 8859-1 (Latin-1)>, but Unicode strings are
+downgraded with UTF-8 encoding. This happens because the first 256
+codepoints in Unicode happens to agree with Latin-1.
+
+See L</"Byte and Character Semantics"> for more details.
+
+=back
+
+=head2 Byte and Character Semantics
+
+Beginning with version 5.6, Perl uses logically-wide characters to
+represent strings internally.
+
+In future, Perl-level operations will be expected to work with
+characters rather than bytes.
+
+However, as an interim compatibility measure, Perl aims to
+provide a safe migration path from byte semantics to character
+semantics for programs. For operations where Perl can unambiguously
+decide that the input data are characters, Perl switches to
+character semantics. For operations where this determination cannot
+be made without additional information from the user, Perl decides in
+favor of compatibility and chooses to use byte semantics.
+
+Under byte semantics, when C<use locale> is in effect, Perl uses the
+semantics associated with the current locale. Absent a C<use locale>, and
+absent a C<use feature 'unicode_strings'> pragma, Perl currently uses US-ASCII
+(or Basic Latin in Unicode terminology) byte semantics, meaning that characters
+whose ordinal numbers are in the range 128 - 255 are undefined except for their
+ordinal numbers. This means that none have case (upper and lower), nor are any
+a member of character classes, like C<[:alpha:]> or C<\w>. (But all do belong
+to the C<\W> class or the Perl regular expression extension C<[:^alpha:]>.)
+
+This behavior preserves compatibility with earlier versions of Perl,
+which allowed byte semantics in Perl operations only if
+none of the program's inputs were marked as being a source of Unicode
+character data. Such data may come from filehandles, from calls to
+external programs, from information provided by the system (such as %ENV),
+or from literals and constants in the source text.
+
+The C<bytes> pragma will always, regardless of platform, force byte
+semantics in a particular lexical scope. See L<bytes>.
+
+The C<use feature 'unicode_strings'> pragma is intended to always, regardless
+of platform, force character (Unicode) semantics in a particular lexical scope.
+In release 5.12, it is partially implemented, applying only to case changes.
+See L</The "Unicode Bug"> below.
+
+The C<utf8> pragma is primarily a compatibility device that enables
+recognition of UTF-(8|EBCDIC) in literals encountered by the parser.
+Note that this pragma is only required while Perl defaults to byte
+semantics; when character semantics become the default, this pragma
+may become a no-op. See L<utf8>.
+
+Unless explicitly stated, Perl operators use character semantics
+for Unicode data and byte semantics for non-Unicode data.
+The decision to use character semantics is made transparently. If
+input data comes from a Unicode source--for example, if a character
+encoding layer is added to a filehandle or a literal Unicode
+string constant appears in a program--character semantics apply.
+Otherwise, byte semantics are in effect. The C<bytes> pragma should
+be used to force byte semantics on Unicode data, and the C<use feature
+'unicode_strings'> pragma to force Unicode semantics on byte data (though in
+5.12 it isn't fully implemented).
+
+If strings operating under byte semantics and strings with Unicode
+character data are concatenated, the new string will have
+character semantics. This can cause surprises: See L</BUGS>, below.
+You can choose to be warned when this happens. See L<encoding::warnings>.
+
+Under character semantics, many operations that formerly operated on
+bytes now operate on characters. A character in Perl is
+logically just a number ranging from 0 to 2**31 or so. Larger
+characters may encode into longer sequences of bytes internally, but
+this internal detail is mostly hidden for Perl code.
+See L<perluniintro> for more.
+
+=head2 Effects of Character Semantics
+
+Character semantics have the following effects:
+
+=over 4
+
+=item *
+
+Strings--including hash keys--and regular expression patterns may
+contain characters that have an ordinal value larger than 255.
+
+If you use a Unicode editor to edit your program, Unicode characters may
+occur directly within the literal strings in UTF-8 encoding, or UTF-16.
+(The former requires a BOM or C<use utf8>, the latter requires a BOM.)
+
+Unicode characters can also be added to a string by using the C<\N{U+...}>
+notation. The Unicode code for the desired character, in hexadecimal,
+should be placed in the braces, after the C<U>. For instance, a smiley face is
+C<\N{U+263A}>.
+
+Alternatively, you can use the C<\x{...}> notation for characters 0x100 and
+above. For characters below 0x100 you may get byte semantics instead of
+character semantics; see L</The "Unicode Bug">. On EBCDIC machines there is
+the additional problem that the value for such characters gives the EBCDIC
+character rather than the Unicode one.
+
+Additionally, if you
+
+ use charnames ':full';
+
+you can use the C<\N{...}> notation and put the official Unicode
+character name within the braces, such as C<\N{WHITE SMILING FACE}>.
+See L<charnames>.
+
+=item *
+
+If an appropriate L<encoding> is specified, identifiers within the
+Perl script may contain Unicode alphanumeric characters, including
+ideographs. Perl does not currently attempt to canonicalize variable
+names.
+
+=item *
+
+Regular expressions match characters instead of bytes. "." matches
+a character instead of a byte.
+
+=item *
+
+Bracketed character classes in regular expressions match characters instead of
+bytes and match against the character properties specified in the
+Unicode properties database. C<\w> can be used to match a Japanese
+ideograph, for instance.
+
+=item *
+
+Named Unicode properties, scripts, and block ranges may be used (like bracketed
+character classes) by using the C<\p{}> "matches property" construct and
+the C<\P{}> negation, "doesn't match property".
+See L</"Unicode Character Properties"> for more details.
+
+You can define your own character properties and use them
+in the regular expression with the C<\p{}> or C<\P{}> construct.
+See L</"User-Defined Character Properties"> for more details.
+
+=item *
+
+The special pattern C<\X> matches a logical character, an "extended grapheme
+cluster" in Standardese. In Unicode what appears to the user to be a single
+character, for example an accented C<G>, may in fact be composed of a sequence
+of characters, in this case a C<G> followed by an accent character. C<\X>
+will match the entire sequence.
+
+=item *
+
+The C<tr///> operator translates characters instead of bytes. Note
+that the C<tr///CU> functionality has been removed. For similar
+functionality see pack('U0', ...) and pack('C0', ...).
+
+=item *
+
+Case translation operators use the Unicode case translation tables
+when character input is provided. Note that C<uc()>, or C<\U> in
+interpolated strings, translates to uppercase, while C<ucfirst>,
+or C<\u> in interpolated strings, translates to titlecase in languages
+that make the distinction (which is equivalent to uppercase in languages
+without the distinction).
+
+=item *
+
+Most operators that deal with positions or lengths in a string will
+automatically switch to using character positions, including
+C<chop()>, C<chomp()>, C<substr()>, C<pos()>, C<index()>, C<rindex()>,
+C<sprintf()>, C<write()>, and C<length()>. An operator that
+specifically does not switch is C<vec()>. Operators that really don't
+care include operators that treat strings as a bucket of bits such as
+C<sort()>, and operators dealing with filenames.
+
+=item *
+
+The C<pack()>/C<unpack()> letter C<C> does I<not> change, since it is often
+used for byte-oriented formats. Again, think C<char> in the C language.
+
+There is a new C<U> specifier that converts between Unicode characters
+and code points. There is also a C<W> specifier that is the equivalent of
+C<chr>/C<ord> and properly handles character values even if they are above 255.
+
+=item *
+
+The C<chr()> and C<ord()> functions work on characters, similar to
+C<pack("W")> and C<unpack("W")>, I<not> C<pack("C")> and
+C<unpack("C")>. C<pack("C")> and C<unpack("C")> are methods for
+emulating byte-oriented C<chr()> and C<ord()> on Unicode strings.
+While these methods reveal the internal encoding of Unicode strings,
+that is not something one normally needs to care about at all.
+
+=item *
+
+The bit string operators, C<& | ^ ~>, can operate on character data.
+However, for backward compatibility, such as when using bit string
+operations when characters are all less than 256 in ordinal value, one
+should not use C<~> (the bit complement) with characters of both
+values less than 256 and values greater than 256. Most importantly,
+DeMorgan's laws (C<~($x|$y) eq ~$x&~$y> and C<~($x&$y) eq ~$x|~$y>)
+will not hold. The reason for this mathematical I<faux pas> is that
+the complement cannot return B<both> the 8-bit (byte-wide) bit
+complement B<and> the full character-wide bit complement.
+
+=item *
+
+You can define your own mappings to be used in C<lc()>,
+C<lcfirst()>, C<uc()>, and C<ucfirst()> (or their double-quoted string inlined
+versions such as C<\U>).
+See L</"User-Defined Case Mappings"> for more details.
+
+=back
+
+=over 4
+
+=item *
+
+And finally, C<scalar reverse()> reverses by character rather than by byte.
+
+=back
+
+=head2 Unicode Character Properties
+
+Most Unicode character properties are accessible by using regular expressions.
+They are used (like bracketed character classes) by using the C<\p{}> "matches
+property" construct and the C<\P{}> negation, "doesn't match property".
+
+Note that the only time that Perl considers a sequence of individual code
+points as a single logical character is in the C<\X> construct, already
+mentioned above. Therefore "character" in this discussion means a single
+Unicode code point.
+
+For instance, C<\p{Uppercase}> matches any single character with the Unicode
+"Uppercase" property, while C<\p{L}> matches any character with a
+General_Category of "L" (letter) property. Brackets are not
+required for single letter property names, so C<\p{L}> is equivalent to C<\pL>.
+
+More formally, C<\p{Uppercase}> matches any single character whose Unicode
+Uppercase property value is True, and C<\P{Uppercase}> matches any character
+whose Uppercase property value is False, and they could have been written as
+C<\p{Uppercase=True}> and C<\p{Uppercase=False}>, respectively.
+
+This formality is needed when properties are not binary, that is if they can
+take on more values than just True and False. For example, the Bidi_Class (see
+L</"Bidirectional Character Types"> below), can take on a number of different
+values, such as Left, Right, Whitespace, and others. To match these, one needs
+to specify the property name (Bidi_Class), and the value being matched against
+(Left, Right, etc.). This is done, as in the examples above, by having the
+two components separated by an equal sign (or interchangeably, a colon), like
+C<\p{Bidi_Class: Left}>.
+
+All Unicode-defined character properties may be written in these compound forms
+of C<\p{property=value}> or C<\p{property:value}>, but Perl provides some
+additional properties that are written only in the single form, as well as
+single-form short-cuts for all binary properties and certain others described
+below, in which you may omit the property name and the equals or colon
+separator.
+
+Most Unicode character properties have at least two synonyms (or aliases if you
+prefer), a short one that is easier to type, and a longer one which is more
+descriptive and hence it is easier to understand what it means. Thus the "L"
+and "Letter" above are equivalent and can be used interchangeably. Likewise,
+"Upper" is a synonym for "Uppercase", and we could have written
+C<\p{Uppercase}> equivalently as C<\p{Upper}>. Also, there are typically
+various synonyms for the values the property can be. For binary properties,
+"True" has 3 synonyms: "T", "Yes", and "Y"; and "False has correspondingly "F",
+"No", and "N". But be careful. A short form of a value for one property may
+not mean the same thing as the same short form for another. Thus, for the
+General_Category property, "L" means "Letter", but for the Bidi_Class property,
+"L" means "Left". A complete list of properties and synonyms is in
+L<perluniprops>.
+
+Upper/lower case differences in the property names and values are irrelevant,
+thus C<\p{Upper}> means the same thing as C<\p{upper}> or even C<\p{UpPeR}>.
+Similarly, you can add or subtract underscores anywhere in the middle of a
+word, so that these are also equivalent to C<\p{U_p_p_e_r}>. And white space
+is irrelevant adjacent to non-word characters, such as the braces and the equals
+or colon separators so C<\p{ Upper }> and C<\p{ Upper_case : Y }> are
+equivalent to these as well. In fact, in most cases, white space and even
+hyphens can be added or deleted anywhere. So even C<\p{ Up-per case = Yes}> is
+equivalent. All this is called "loose-matching" by Unicode. The few places
+where stricter matching is employed is in the middle of numbers, and the Perl
+extension properties that begin or end with an underscore. Stricter matching
+cares about white space (except adjacent to the non-word characters) and
+hyphens, and non-interior underscores.
+
+You can also use negation in both C<\p{}> and C<\P{}> by introducing a caret
+(^) between the first brace and the property name: C<\p{^Tamil}> is
+equal to C<\P{Tamil}>.
+
+=head3 B<General_Category>
+
+Every Unicode character is assigned a general category, which is the "most
+usual categorization of a character" (from
+L<http://www.unicode.org/reports/tr44>).
+
+The compound way of writing these is like C<\p{General_Category=Number}>
+(short, C<\p{gc:n}>). But Perl furnishes shortcuts in which everything up
+through the equal or colon separator is omitted. So you can instead just write
+C<\pN>.
+
+Here are the short and long forms of the General Category properties:
+
+ Short Long
+
+ L Letter
+ LC, L& Cased_Letter (that is: [\p{Ll}\p{Lu}\p{Lt}])
+ Lu Uppercase_Letter
+ Ll Lowercase_Letter
+ Lt Titlecase_Letter
+ Lm Modifier_Letter
+ Lo Other_Letter
+
+ M Mark
+ Mn Nonspacing_Mark
+ Mc Spacing_Mark
+ Me Enclosing_Mark
+
+ N Number
+ Nd Decimal_Number (also Digit)
+ Nl Letter_Number
+ No Other_Number
+
+ P Punctuation (also Punct)
+ Pc Connector_Punctuation
+ Pd Dash_Punctuation
+ Ps Open_Punctuation
+ Pe Close_Punctuation
+ Pi Initial_Punctuation
+ (may behave like Ps or Pe depending on usage)
+ Pf Final_Punctuation
+ (may behave like Ps or Pe depending on usage)
+ Po Other_Punctuation
+
+ S Symbol
+ Sm Math_Symbol
+ Sc Currency_Symbol
+ Sk Modifier_Symbol
+ So Other_Symbol
+
+ Z Separator
+ Zs Space_Separator
+ Zl Line_Separator
+ Zp Paragraph_Separator
+
+ C Other
+ Cc Control (also Cntrl)
+ Cf Format
+ Cs Surrogate (not usable)
+ Co Private_Use
+ Cn Unassigned
+
+Single-letter properties match all characters in any of the
+two-letter sub-properties starting with the same letter.
+C<LC> and C<L&> are special cases, which are both aliases for the set consisting of everything matched by C<Ll>, C<Lu>, and C<Lt>.
+
+Because Perl hides the need for the user to understand the internal
+representation of Unicode characters, there is no need to implement
+the somewhat messy concept of surrogates. C<Cs> is therefore not
+supported.
+
+=head3 B<Bidirectional Character Types>
+
+Because scripts differ in their directionality (Hebrew is
+written right to left, for example) Unicode supplies these properties in
+the Bidi_Class class:
+
+ Property Meaning
+
+ L Left-to-Right
+ LRE Left-to-Right Embedding
+ LRO Left-to-Right Override
+ R Right-to-Left
+ AL Arabic Letter
+ RLE Right-to-Left Embedding
+ RLO Right-to-Left Override
+ PDF Pop Directional Format
+ EN European Number
+ ES European Separator
+ ET European Terminator
+ AN Arabic Number
+ CS Common Separator
+ NSM Non-Spacing Mark
+ BN Boundary Neutral
+ B Paragraph Separator
+ S Segment Separator
+ WS Whitespace
+ ON Other Neutrals
+
+This property is always written in the compound form.
+For example, C<\p{Bidi_Class:R}> matches characters that are normally
+written right to left.
+
+=head3 B<Scripts>
+
+The world's languages are written in a number of scripts. This sentence
+(unless you're reading it in translation) is written in Latin, while Russian is
+written in Cyrllic, and Greek is written in, well, Greek; Japanese mainly in
+Hiragana or Katakana. There are many more.
+
+The Unicode Script property gives what script a given character is in,
+and the property can be specified with the compound form like
+C<\p{Script=Hebrew}> (short: C<\p{sc=hebr}>). Perl furnishes shortcuts for all
+script names. You can omit everything up through the equals (or colon), and
+simply write C<\p{Latin}> or C<\P{Cyrillic}>.
+
+A complete list of scripts and their shortcuts is in L<perluniprops>.
+
+=head3 B<Use of "Is" Prefix>
+
+For backward compatibility (with Perl 5.6), all properties mentioned
+so far may have C<Is> or C<Is_> prepended to their name, so C<\P{Is_Lu}>, for
+example, is equal to C<\P{Lu}>, and C<\p{IsScript:Arabic}> is equal to
+C<\p{Arabic}>.
+
+=head3 B<Blocks>
+
+In addition to B<scripts>, Unicode also defines B<blocks> of
+characters. The difference between scripts and blocks is that the
+concept of scripts is closer to natural languages, while the concept
+of blocks is more of an artificial grouping based on groups of Unicode
+characters with consecutive ordinal values. For example, the "Basic Latin"
+block is all characters whose ordinals are between 0 and 127, inclusive, in
+other words, the ASCII characters. The "Latin" script contains some letters
+from this block as well as several more, like "Latin-1 Supplement",
+"Latin Extended-A", etc., but it does not contain all the characters from
+those blocks. It does not, for example, contain digits, because digits are
+shared across many scripts. Digits and similar groups, like punctuation, are in
+the script called C<Common>. There is also a script called C<Inherited> for
+characters that modify other characters, and inherit the script value of the
+controlling character.
+
+For more about scripts versus blocks, see UAX#24 "Unicode Script Property":
+L<http://www.unicode.org/reports/tr24>
+
+The Script property is likely to be the one you want to use when processing
+natural language; the Block property may be useful in working with the nuts and
+bolts of Unicode.
+
+Block names are matched in the compound form, like C<\p{Block: Arrows}> or
+C<\p{Blk=Hebrew}>. Unlike most other properties only a few block names have a
+Unicode-defined short name. But Perl does provide a (slight) shortcut: You
+can say, for example C<\p{In_Arrows}> or C<\p{In_Hebrew}>. For backwards
+compatibility, the C<In> prefix may be omitted if there is no naming conflict
+with a script or any other property, and you can even use an C<Is> prefix
+instead in those cases. But it is not a good idea to do this, for a couple
+reasons:
+
+=over 4
+
+=item 1
+
+It is confusing. There are many naming conflicts, and you may forget some.
+For example, C<\p{Hebrew}> means the I<script> Hebrew, and NOT the I<block>
+Hebrew. But would you remember that 6 months from now?
+
+=item 2
+
+It is unstable. A new version of Unicode may pre-empt the current meaning by
+creating a property with the same name. There was a time in very early Unicode
+releases when C<\p{Hebrew}> would have matched the I<block> Hebrew; now it
+doesn't.
+
+=back
+
+Some people just prefer to always use C<\p{Block: foo}> and C<\p{Script: bar}>
+instead of the shortcuts, for clarity, and because they can't remember the
+difference between 'In' and 'Is' anyway (or aren't confident that those who
+eventually will read their code will know).
+
+A complete list of blocks and their shortcuts is in L<perluniprops>.
+
+=head3 B<Other Properties>
+
+There are many more properties than the very basic ones described here.
+A complete list is in L<perluniprops>.
+
+Unicode defines all its properties in the compound form, so all single-form
+properties are Perl extensions. A number of these are just synonyms for the
+Unicode ones, but some are genunine extensions, including a couple that are in
+the compound form. And quite a few of these are actually recommended by Unicode
+(in L<http://www.unicode.org/reports/tr18>).
+
+This section gives some details on all the extensions that aren't synonyms for
+compound-form Unicode properties (for those, you'll have to refer to the
+L<Unicode Standard|http://www.unicode.org/reports/tr44>.
+
+=over
+
+=item B<C<\p{All}>>
+
+This matches any of the 1_114_112 Unicode code points. It is a synonym for
+C<\p{Any}>.
+
+=item B<C<\p{Alnum}>>
+
+This matches any C<\p{Alphabetic}> or C<\p{Decimal_Number}> character.
+
+=item B<C<\p{Any}>>
+
+This matches any of the 1_114_112 Unicode code points. It is a synonym for
+C<\p{All}>.
+
+=item B<C<\p{Assigned}>>
+
+This matches any assigned code point; that is, any code point whose general
+category is not Unassigned (or equivalently, not Cn).
+
+=item B<C<\p{Blank}>>
+
+This is the same as C<\h> and C<\p{HorizSpace}>: A character that changes the
+spacing horizontally.
+
+=item B<C<\p{Decomposition_Type: Non_Canonical}>> (Short: C<\p{Dt=NonCanon}>)
+
+Matches a character that has a non-canonical decomposition.
+
+To understand the use of this rarely used property=value combination, it is
+necessary to know some basics about decomposition.
+Consider a character, say H. It could appear with various marks around it,
+such as an acute accent, or a circumflex, or various hooks, circles, arrows,
+I<etc.>, above, below, to one side and/or the other, etc. There are many
+possibilities among the world's languages. The number of combinations is
+astronomical, and if there were a character for each combination, it would
+soon exhaust Unicode's more than a million possible characters. So Unicode
+took a different approach: there is a character for the base H, and a
+character for each of the possible marks, and they can be combined variously
+to get a final logical character. So a logical character--what appears to be a
+single character--can be a sequence of more than one individual characters.
+This is called an "extended grapheme cluster". (Perl furnishes the C<\X>
+construct to match such sequences.)
+
+But Unicode's intent is to unify the existing character set standards and
+practices, and a number of pre-existing standards have single characters that
+mean the same thing as some of these combinations. An example is ISO-8859-1,
+which has quite a few of these in the Latin-1 range, an example being "LATIN
+CAPITAL LETTER E WITH ACUTE". Because this character was in this pre-existing
+standard, Unicode added it to its repertoire. But this character is considered
+by Unicode to be equivalent to the sequence consisting of first the character
+"LATIN CAPITAL LETTER E", then the character "COMBINING ACUTE ACCENT".
+
+"LATIN CAPITAL LETTER E WITH ACUTE" is called a "pre-composed" character, and
+the equivalence with the sequence is called canonical equivalence. All
+pre-composed characters are said to have a decomposition (into the equivalent
+sequence) and the decomposition type is also called canonical.
+
+However, many more characters have a different type of decomposition, a
+"compatible" or "non-canonical" decomposition. The sequences that form these
+decompositions are not considered canonically equivalent to the pre-composed
+character. An example, again in the Latin-1 range, is the "SUPERSCRIPT ONE".
+It is kind of like a regular digit 1, but not exactly; its decomposition
+into the digit 1 is called a "compatible" decomposition, specifically a
+"super" decomposition. There are several such compatibility
+decompositions (see L<http://www.unicode.org/reports/tr44>), including one
+called "compat" which means some miscellaneous type of decomposition
+that doesn't fit into the decomposition categories that Unicode has chosen.
+
+Note that most Unicode characters don't have a decomposition, so their
+decomposition type is "None".
+
+Perl has added the C<Non_Canonical> type, for your convenience, to mean any of
+the compatibility decompositions.
+
+=item B<C<\p{Graph}>>
+
+Matches any character that is graphic. Theoretically, this means a character
+that on a printer would cause ink to be used.
+
+=item B<C<\p{HorizSpace}>>
+
+This is the same as C<\h> and C<\p{Blank}>: A character that changes the
+spacing horizontally.
+
+=item B<C<\p{In=*}>>
+
+This is a synonym for C<\p{Present_In=*}>
+
+=item B<C<\p{PerlSpace}>>
+
+This is the same as C<\s>, restricted to ASCII, namely C<S<[ \f\n\r\t]>>.
+
+Mnemonic: Perl's (original) space
+
+=item B<C<\p{PerlWord}>>
+
+This is the same as C<\w>, restricted to ASCII, namely C<[A-Za-z0-9_]>
+
+Mnemonic: Perl's (original) word.
+
+=item B<C<\p{PosixAlnum}>>
+
+This matches any alphanumeric character in the ASCII range, namely
+C<[A-Za-z0-9]>.
+
+=item B<C<\p{PosixAlpha}>>
+
+This matches any alphabetic character in the ASCII range, namely C<[A-Za-z]>.
+
+=item B<C<\p{PosixBlank}>>
+
+This matches any blank character in the ASCII range, namely C<S<[ \t]>>.
+
+=item B<C<\p{PosixCntrl}>>
+
+This matches any control character in the ASCII range, namely C<[\x00-\x1F\x7F]>
+
+=item B<C<\p{PosixDigit}>>
+
+This matches any digit character in the ASCII range, namely C<[0-9]>.
+
+=item B<C<\p{PosixGraph}>>
+
+This matches any graphical character in the ASCII range, namely C<[\x21-\x7E]>.
+
+=item B<C<\p{PosixLower}>>
+
+This matches any lowercase character in the ASCII range, namely C<[a-z]>.
+
+=item B<C<\p{PosixPrint}>>
+
+This matches any printable character in the ASCII range, namely C<[\x20-\x7E]>.
+These are the graphical characters plus SPACE.
+
+=item B<C<\p{PosixPunct}>>
+
+This matches any punctuation character in the ASCII range, namely
+C<[\x21-\x2F\x3A-\x40\x5B-\x60\x7B-\x7E]>. These are the
+graphical characters that aren't word characters. Note that the Posix standard
+includes in its definition of punctuation, those characters that Unicode calls
+"symbols."
+
+=item B<C<\p{PosixSpace}>>
+
+This matches any space character in the ASCII range, namely
+C<S<[ \f\n\r\t\x0B]>> (the last being a vertical tab).
+
+=item B<C<\p{PosixUpper}>>
+
+This matches any uppercase character in the ASCII range, namely C<[A-Z]>.
+
+=item B<C<\p{Present_In: *}>> (Short: C<\p{In=*}>)
+
+This property is used when you need to know in what Unicode version(s) a
+character is.
+
+The "*" above stands for some two digit Unicode version number, such as
+C<1.1> or C<4.0>; or the "*" can also be C<Unassigned>. This property will
+match the code points whose final disposition has been settled as of the
+Unicode release given by the version number; C<\p{Present_In: Unassigned}>
+will match those code points whose meaning has yet to be assigned.
+
+For example, C<U+0041> "LATIN CAPITAL LETTER A" was present in the very first
+Unicode release available, which is C<1.1>, so this property is true for all
+valid "*" versions. On the other hand, C<U+1EFF> was not assigned until version
+5.1 when it became "LATIN SMALL LETTER Y WITH LOOP", so the only "*" that
+would match it are 5.1, 5.2, and later.
+
+Unicode furnishes the C<Age> property from which this is derived. The problem
+with Age is that a strict interpretation of it (which Perl takes) has it
+matching the precise release a code point's meaning is introduced in. Thus
+C<U+0041> would match only 1.1; and C<U+1EFF> only 5.1. This is not usually what
+you want.
+
+Some non-Perl implementations of the Age property may change its meaning to be
+the same as the Perl Present_In property; just be aware of that.
+
+Another confusion with both these properties is that the definition is not
+that the code point has been assigned, but that the meaning of the code point
+has been determined. This is because 66 code points will always be
+unassigned, and, so the Age for them is the Unicode version the decision to
+make them so was made in. For example, C<U+FDD0> is to be permanently
+unassigned to a character, and the decision to do that was made in version 3.1,
+so C<\p{Age=3.1}> matches this character and C<\p{Present_In: 3.1}> and up
+matches as well.
+
+=item B<C<\p{Print}>>
+
+This matches any character that is graphical or blank, except controls.
+
+=item B<C<\p{SpacePerl}>>
+
+This is the same as C<\s>, including beyond ASCII.
+
+Mnemonic: Space, as modified by Perl. (It doesn't include the vertical tab
+which both the Posix standard and Unicode consider to be space.)
+
+=item B<C<\p{VertSpace}>>
+
+This is the same as C<\v>: A character that changes the spacing vertically.
+
+=item B<C<\p{Word}>>
+
+This is the same as C<\w>, including beyond ASCII.
+
+=back
+
+=head2 User-Defined Character Properties
+
+You can define your own binary character properties by defining subroutines
+whose names begin with "In" or "Is". The subroutines can be defined in any
+package. The user-defined properties can be used in the regular expression
+C<\p> and C<\P> constructs; if you are using a user-defined property from a
+package other than the one you are in, you must specify its package in the
+C<\p> or C<\P> construct.
+
+ # assuming property Is_Foreign defined in Lang::
+ package main; # property package name required
+ if ($txt =~ /\p{Lang::IsForeign}+/) { ... }
+
+ package Lang; # property package name not required
+ if ($txt =~ /\p{IsForeign}+/) { ... }
+
+
+Note that the effect is compile-time and immutable once defined.
+
+The subroutines must return a specially-formatted string, with one
+or more newline-separated lines. Each line must be one of the following:
+
+=over 4
+
+=item *
+
+A single hexadecimal number denoting a Unicode code point to include.
+
+=item *
+
+Two hexadecimal numbers separated by horizontal whitespace (space or
+tabular characters) denoting a range of Unicode code points to include.
+
+=item *
+
+Something to include, prefixed by "+": a built-in character
+property (prefixed by "utf8::") or a user-defined character property,
+to represent all the characters in that property; two hexadecimal code
+points for a range; or a single hexadecimal code point.
+
+=item *
+
+Something to exclude, prefixed by "-": an existing character
+property (prefixed by "utf8::") or a user-defined character property,
+to represent all the characters in that property; two hexadecimal code
+points for a range; or a single hexadecimal code point.
+
+=item *
+
+Something to negate, prefixed "!": an existing character
+property (prefixed by "utf8::") or a user-defined character property,
+to represent all the characters in that property; two hexadecimal code
+points for a range; or a single hexadecimal code point.
+
+=item *
+
+Something to intersect with, prefixed by "&": an existing character
+property (prefixed by "utf8::") or a user-defined character property,
+for all the characters except the characters in the property; two
+hexadecimal code points for a range; or a single hexadecimal code point.
+
+=back
+
+For example, to define a property that covers both the Japanese
+syllabaries (hiragana and katakana), you can define
+
+ sub InKana {
+ return <<END;
+ 3040\t309F
+ 30A0\t30FF
+ END
+ }
+
+Imagine that the here-doc end marker is at the beginning of the line.
+Now you can use C<\p{InKana}> and C<\P{InKana}>.
+
+You could also have used the existing block property names:
+
+ sub InKana {
+ return <<'END';
+ +utf8::InHiragana
+ +utf8::InKatakana
+ END
+ }
+
+Suppose you wanted to match only the allocated characters,
+not the raw block ranges: in other words, you want to remove
+the non-characters:
+
+ sub InKana {
+ return <<'END';
+ +utf8::InHiragana
+ +utf8::InKatakana
+ -utf8::IsCn
+ END
+ }
+
+The negation is useful for defining (surprise!) negated classes.
+
+ sub InNotKana {
+ return <<'END';
+ !utf8::InHiragana
+ -utf8::InKatakana
+ +utf8::IsCn
+ END
+ }
+
+Intersection is useful for getting the common characters matched by
+two (or more) classes.
+
+ sub InFooAndBar {
+ return <<'END';
+ +main::Foo
+ &main::Bar
+ END
+ }
+
+It's important to remember not to use "&" for the first set; that
+would be intersecting with nothing (resulting in an empty set).
+
+=head2 User-Defined Case Mappings
+
+You can also define your own mappings to be used in the lc(),
+lcfirst(), uc(), and ucfirst() (or their string-inlined versions).
+The principle is similar to that of user-defined character
+properties: to define subroutines
+with names like C<ToLower> (for lc() and lcfirst()), C<ToTitle> (for
+the first character in ucfirst()), and C<ToUpper> (for uc(), and the
+rest of the characters in ucfirst()).
+
+The string returned by the subroutines needs to be two hexadecimal numbers
+separated by two tabulators: the two numbers being, respectively, the source
+code point and the destination code point. For example:
+
+ sub ToUpper {
+ return <<END;
+ 0061\t\t0041
+ END
+ }
+
+defines an uc() mapping that causes only the character "a"
+to be mapped to "A"; all other characters will remain unchanged.
+
+(For serious hackers only) The above means you have to furnish a complete
+mapping; you can't just override a couple of characters and leave the rest
+unchanged. You can find all the mappings in the directory
+C<$Config{privlib}>/F<unicore/To/>. The mapping data is returned as the
+here-document, and the C<utf8::ToSpecFoo> are special exception mappings
+derived from <$Config{privlib}>/F<unicore/SpecialCasing.txt>. The "Digit" and
+"Fold" mappings that one can see in the directory are not directly
+user-accessible, one can use either the C<Unicode::UCD> module, or just match
+case-insensitively (that's when the "Fold" mapping is used).
+
+The mappings will only take effect on scalars that have been marked as having
+Unicode characters, for example by using C<utf8::upgrade()>.
+Old byte-style strings are not affected.
+
+The mappings are in effect for the package they are defined in.
+
+=head2 Character Encodings for Input and Output
+
+See L<Encode>.
+
+=head2 Unicode Regular Expression Support Level
+
+The following list of Unicode support for regular expressions describes
+all the features currently supported. The references to "Level N"
+and the section numbers refer to the Unicode Technical Standard #18,
+"Unicode Regular Expressions", version 11, in May 2005.
+
+=over 4
+
+=item *
+
+Level 1 - Basic Unicode Support
+
+ RL1.1 Hex Notation - done [1]
+ RL1.2 Properties - done [2][3]
+ RL1.2a Compatibility Properties - done [4]
+ RL1.3 Subtraction and Intersection - MISSING [5]
+ RL1.4 Simple Word Boundaries - done [6]
+ RL1.5 Simple Loose Matches - done [7]
+ RL1.6 Line Boundaries - MISSING [8]
+ RL1.7 Supplementary Code Points - done [9]
+
+ [1] \x{...}
+ [2] \p{...} \P{...}
+ [3] supports not only minimal list, but all Unicode character
+ properties (see L</Unicode Character Properties>)
+ [4] \d \D \s \S \w \W \X [:prop:] [:^prop:]
+ [5] can use regular expression look-ahead [a] or
+ user-defined character properties [b] to emulate set operations
+ [6] \b \B
+ [7] note that Perl does Full case-folding in matching (but with bugs),
+ not Simple: for example U+1F88 is equivalent to U+1F00 U+03B9,
+ not with 1F80. This difference matters mainly for certain Greek
+ capital letters with certain modifiers: the Full case-folding
+ decomposes the letter, while the Simple case-folding would map
+ it to a single character.
+ [8] should do ^ and $ also on U+000B (\v in C), FF (\f), CR (\r),
+ CRLF (\r\n), NEL (U+0085), LS (U+2028), and PS (U+2029);
+ should also affect <>, $., and script line numbers;
+ should not split lines within CRLF [c] (i.e. there is no empty
+ line between \r and \n)
+ [9] UTF-8/UTF-EBDDIC used in perl allows not only U+10000 to U+10FFFF
+ but also beyond U+10FFFF [d]
+
+[a] You can mimic class subtraction using lookahead.
+For example, what UTS#18 might write as
+
+ [{Greek}-[{UNASSIGNED}]]
+
+in Perl can be written as:
+
+ (?!\p{Unassigned})\p{InGreekAndCoptic}
+ (?=\p{Assigned})\p{InGreekAndCoptic}
+
+But in this particular example, you probably really want
+
+ \p{GreekAndCoptic}
+
+which will match assigned characters known to be part of the Greek script.
+
+Also see the Unicode::Regex::Set module, it does implement the full
+UTS#18 grouping, intersection, union, and removal (subtraction) syntax.
+
+[b] '+' for union, '-' for removal (set-difference), '&' for intersection
+(see L</"User-Defined Character Properties">)
+
+[c] Try the C<:crlf> layer (see L<PerlIO>).
+
+[d] U+FFFF will currently generate a warning message if 'utf8' warnings are
+ enabled
+
+=item *
+
+Level 2 - Extended Unicode Support
+
+ RL2.1 Canonical Equivalents - MISSING [10][11]
+ RL2.2 Default Grapheme Clusters - MISSING [12]
+ RL2.3 Default Word Boundaries - MISSING [14]
+ RL2.4 Default Loose Matches - MISSING [15]
+ RL2.5 Name Properties - MISSING [16]
+ RL2.6 Wildcard Properties - MISSING
+
+ [10] see UAX#15 "Unicode Normalization Forms"
+ [11] have Unicode::Normalize but not integrated to regexes
+ [12] have \X but we don't have a "Grapheme Cluster Mode"
+ [14] see UAX#29, Word Boundaries
+ [15] see UAX#21 "Case Mappings"
+ [16] have \N{...} but neither compute names of CJK Ideographs
+ and Hangul Syllables nor use a loose match [e]
+
+[e] C<\N{...}> allows namespaces (see L<charnames>).
+
+=item *
+
+Level 3 - Tailored Support
+
+ RL3.1 Tailored Punctuation - MISSING
+ RL3.2 Tailored Grapheme Clusters - MISSING [17][18]
+ RL3.3 Tailored Word Boundaries - MISSING
+ RL3.4 Tailored Loose Matches - MISSING
+ RL3.5 Tailored Ranges - MISSING
+ RL3.6 Context Matching - MISSING [19]
+ RL3.7 Incremental Matches - MISSING
+ ( RL3.8 Unicode Set Sharing )
+ RL3.9 Possible Match Sets - MISSING
+ RL3.10 Folded Matching - MISSING [20]
+ RL3.11 Submatchers - MISSING
+
+ [17] see UAX#10 "Unicode Collation Algorithms"
+ [18] have Unicode::Collate but not integrated to regexes
+ [19] have (?<=x) and (?=x), but look-aheads or look-behinds should see
+ outside of the target substring
+ [20] need insensitive matching for linguistic features other than case;
+ for example, hiragana to katakana, wide and narrow, simplified Han
+ to traditional Han (see UTR#30 "Character Foldings")
+
+=back
+
+=head2 Unicode Encodings
+
+Unicode characters are assigned to I<code points>, which are abstract
+numbers. To use these numbers, various encodings are needed.
+
+=over 4
+
+=item *
+
+UTF-8
+
+UTF-8 is a variable-length (1 to 6 bytes, current character allocations
+require 4 bytes), byte-order independent encoding. For ASCII (and we
+really do mean 7-bit ASCII, not another 8-bit encoding), UTF-8 is
+transparent.
+
+The following table is from Unicode 3.2.
+
+ Code Points 1st Byte 2nd Byte 3rd Byte 4th Byte
+
+ U+0000..U+007F 00..7F
+ U+0080..U+07FF * C2..DF 80..BF
+ U+0800..U+0FFF E0 * A0..BF 80..BF
+ U+1000..U+CFFF E1..EC 80..BF 80..BF
+ U+D000..U+D7FF ED 80..9F 80..BF
+ U+D800..U+DFFF +++++++ utf16 surrogates, not legal utf8 +++++++
+ U+E000..U+FFFF EE..EF 80..BF 80..BF
+ U+10000..U+3FFFF F0 * 90..BF 80..BF 80..BF
+ U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
+ U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
+
+Note the gaps before several of the byte entries above marked by '*'. These are
+caused by legal UTF-8 avoiding non-shortest encodings: it is technically
+possible to UTF-8-encode a single code point in different ways, but that is
+explicitly forbidden, and the shortest possible encoding should always be used
+(and that is what Perl does).
+
+Another way to look at it is via bits:
+
+ Code Points 1st Byte 2nd Byte 3rd Byte 4th Byte
+
+ 0aaaaaaa 0aaaaaaa
+ 00000bbbbbaaaaaa 110bbbbb 10aaaaaa
+ ccccbbbbbbaaaaaa 1110cccc 10bbbbbb 10aaaaaa
+ 00000dddccccccbbbbbbaaaaaa 11110ddd 10cccccc 10bbbbbb 10aaaaaa
+
+As you can see, the continuation bytes all begin with "10", and the
+leading bits of the start byte tell how many bytes there are in the
+encoded character.
+
+=item *
+
+UTF-EBCDIC
+
+Like UTF-8 but EBCDIC-safe, in the way that UTF-8 is ASCII-safe.
+
+=item *
+
+UTF-16, UTF-16BE, UTF-16LE, Surrogates, and BOMs (Byte Order Marks)
+
+The followings items are mostly for reference and general Unicode
+knowledge, Perl doesn't use these constructs internally.
+
+UTF-16 is a 2 or 4 byte encoding. The Unicode code points
+C<U+0000..U+FFFF> are stored in a single 16-bit unit, and the code
+points C<U+10000..U+10FFFF> in two 16-bit units. The latter case is
+using I<surrogates>, the first 16-bit unit being the I<high
+surrogate>, and the second being the I<low surrogate>.
+
+Surrogates are code points set aside to encode the C<U+10000..U+10FFFF>
+range of Unicode code points in pairs of 16-bit units. The I<high
+surrogates> are the range C<U+D800..U+DBFF> and the I<low surrogates>
+are the range C<U+DC00..U+DFFF>. The surrogate encoding is
+
+ $hi = ($uni - 0x10000) / 0x400 + 0xD800;
+ $lo = ($uni - 0x10000) % 0x400 + 0xDC00;
+
+and the decoding is
+
+ $uni = 0x10000 + ($hi - 0xD800) * 0x400 + ($lo - 0xDC00);
+
+If you try to generate surrogates (for example by using chr()), you
+will get a warning, if warnings are turned on, because those code
+points are not valid for a Unicode character.
+
+Because of the 16-bitness, UTF-16 is byte-order dependent. UTF-16
+itself can be used for in-memory computations, but if storage or
+transfer is required either UTF-16BE (big-endian) or UTF-16LE
+(little-endian) encodings must be chosen.
+
+This introduces another problem: what if you just know that your data
+is UTF-16, but you don't know which endianness? Byte Order Marks, or
+BOMs, are a solution to this. A special character has been reserved
+in Unicode to function as a byte order marker: the character with the
+code point C<U+FEFF> is the BOM.
+
+The trick is that if you read a BOM, you will know the byte order,
+since if it was written on a big-endian platform, you will read the
+bytes C<0xFE 0xFF>, but if it was written on a little-endian platform,
+you will read the bytes C<0xFF 0xFE>. (And if the originating platform
+was writing in UTF-8, you will read the bytes C<0xEF 0xBB 0xBF>.)
+
+The way this trick works is that the character with the code point
+C<U+FFFE> is guaranteed not to be a valid Unicode character, so the
+sequence of bytes C<0xFF 0xFE> is unambiguously "BOM, represented in
+little-endian format" and cannot be C<U+FFFE>, represented in big-endian
+format". (Actually, C<U+FFFE> is legal for use by your program, even for
+input/output, but better not use it if you need a BOM. But it is "illegal for
+interchange", so that an unsuspecting program won't get confused.)
+
+=item *
+
+UTF-32, UTF-32BE, UTF-32LE
+
+The UTF-32 family is pretty much like the UTF-16 family, expect that
+the units are 32-bit, and therefore the surrogate scheme is not
+needed. The BOM signatures will be C<0x00 0x00 0xFE 0xFF> for BE and
+C<0xFF 0xFE 0x00 0x00> for LE.
+
+=item *
+
+UCS-2, UCS-4
+
+Encodings defined by the ISO 10646 standard. UCS-2 is a 16-bit
+encoding. Unlike UTF-16, UCS-2 is not extensible beyond C<U+FFFF>,
+because it does not use surrogates. UCS-4 is a 32-bit encoding,
+functionally identical to UTF-32.
+
+=item *
+
+UTF-7
+
+A seven-bit safe (non-eight-bit) encoding, which is useful if the
+transport or storage is not eight-bit safe. Defined by RFC 2152.
+
+=back
+
+=head2 Security Implications of Unicode
+
+Read L<Unicode Security Considerations|http://www.unicode.org/reports/tr36>.
+Also, note the following:
+
+=over 4
+
+=item *
+
+Malformed UTF-8
+
+Unfortunately, the specification of UTF-8 leaves some room for
+interpretation of how many bytes of encoded output one should generate
+from one input Unicode character. Strictly speaking, the shortest
+possible sequence of UTF-8 bytes should be generated,
+because otherwise there is potential for an input buffer overflow at
+the receiving end of a UTF-8 connection. Perl always generates the
+shortest length UTF-8, and with warnings on, Perl will warn about
+non-shortest length UTF-8 along with other malformations, such as the
+surrogates, which are not real Unicode code points.
+
+=item *
+
+Regular expressions behave slightly differently between byte data and
+character (Unicode) data. For example, the "word character" character
+class C<\w> will work differently depending on if data is eight-bit bytes
+or Unicode.
+
+In the first case, the set of C<\w> characters is either small--the
+default set of alphabetic characters, digits, and the "_"--or, if you
+are using a locale (see L<perllocale>), the C<\w> might contain a few
+more letters according to your language and country.
+
+In the second case, the C<\w> set of characters is much, much larger.
+Most importantly, even in the set of the first 256 characters, it will
+probably match different characters: unlike most locales, which are
+specific to a language and country pair, Unicode classifies all the
+characters that are letters I<somewhere> as C<\w>. For example, your
+locale might not think that LATIN SMALL LETTER ETH is a letter (unless
+you happen to speak Icelandic), but Unicode does.
+
+As discussed elsewhere, Perl has one foot (two hooves?) planted in
+each of two worlds: the old world of bytes and the new world of
+characters, upgrading from bytes to characters when necessary.
+If your legacy code does not explicitly use Unicode, no automatic
+switch-over to characters should happen. Characters shouldn't get
+downgraded to bytes, either. It is possible to accidentally mix bytes
+and characters, however (see L<perluniintro>), in which case C<\w> in
+regular expressions might start behaving differently. Review your
+code. Use warnings and the C<strict> pragma.
+
+=back
+
+=head2 Unicode in Perl on EBCDIC
+
+The way Unicode is handled on EBCDIC platforms is still
+experimental. On such platforms, references to UTF-8 encoding in this
+document and elsewhere should be read as meaning the UTF-EBCDIC
+specified in Unicode Technical Report 16, unless ASCII vs. EBCDIC issues
+are specifically discussed. There is no C<utfebcdic> pragma or
+":utfebcdic" layer; rather, "utf8" and ":utf8" are reused to mean
+the platform's "natural" 8-bit encoding of Unicode. See L<perlebcdic>
+for more discussion of the issues.
+
+=head2 Locales
+
+Usually locale settings and Unicode do not affect each other, but
+there are a couple of exceptions:
+
+=over 4
+
+=item *
+
+You can enable automatic UTF-8-ification of your standard file
+handles, default C<open()> layer, and C<@ARGV> by using either
+the C<-C> command line switch or the C<PERL_UNICODE> environment
+variable, see L<perlrun> for the documentation of the C<-C> switch.
+
+=item *
+
+Perl tries really hard to work both with Unicode and the old
+byte-oriented world. Most often this is nice, but sometimes Perl's
+straddling of the proverbial fence causes problems.
+
+=back
+
+=head2 When Unicode Does Not Happen
+
+While Perl does have extensive ways to input and output in Unicode,
+and few other 'entry points' like the @ARGV which can be interpreted
+as Unicode (UTF-8), there still are many places where Unicode (in some
+encoding or another) could be given as arguments or received as
+results, or both, but it is not.
+
+The following are such interfaces. Also, see L</The "Unicode Bug">.
+For all of these interfaces Perl
+currently (as of 5.8.3) simply assumes byte strings both as arguments
+and results, or UTF-8 strings if the C<encoding> pragma has been used.
+
+One reason why Perl does not attempt to resolve the role of Unicode in
+these cases is that the answers are highly dependent on the operating
+system and the file system(s). For example, whether filenames can be
+in Unicode, and in exactly what kind of encoding, is not exactly a
+portable concept. Similarly for the qx and system: how well will the
+'command line interface' (and which of them?) handle Unicode?
+
+=over 4
+
+=item *
+
+chdir, chmod, chown, chroot, exec, link, lstat, mkdir,
+rename, rmdir, stat, symlink, truncate, unlink, utime, -X
+
+=item *
+
+%ENV
+
+=item *
+
+glob (aka the <*>)
+
+=item *
+
+open, opendir, sysopen
+
+=item *
+
+qx (aka the backtick operator), system
+
+=item *
+
+readdir, readlink
+
+=back
+
+=head2 The "Unicode Bug"
+
+The term, the "Unicode bug" has been applied to an inconsistency with the
+Unicode characters whose ordinals are in the Latin-1 Supplement block, that
+is, between 128 and 255. Without a locale specified, unlike all other
+characters or code points, these characters have very different semantics in
+byte semantics versus character semantics.
+
+In character semantics they are interpreted as Unicode code points, which means
+they have the same semantics as Latin-1 (ISO-8859-1).
+
+In byte semantics, they are considered to be unassigned characters, meaning
+that the only semantics they have is their ordinal numbers, and that they are
+not members of various character classes. None are considered to match C<\w>
+for example, but all match C<\W>. (On EBCDIC platforms, the behavior may
+be different from this, depending on the underlying C language library
+functions.)
+
+The behavior is known to have effects on these areas:
+
+=over 4
+
+=item *
+
+Changing the case of a scalar, that is, using C<uc()>, C<ucfirst()>, C<lc()>,
+and C<lcfirst()>, or C<\L>, C<\U>, C<\u> and C<\l> in regular expression
+substitutions.
+
+=item *
+
+Using caseless (C</i>) regular expression matching
+
+=item *
+
+Matching a number of properties in regular expressions, such as C<\w>
+
+=item *
+
+User-defined case change mappings. You can create a C<ToUpper()> function, for
+example, which overrides Perl's built-in case mappings. The scalar must be
+encoded in utf8 for your function to actually be invoked.
+
+=back
+
+This behavior can lead to unexpected results in which a string's semantics
+suddenly change if a code point above 255 is appended to or removed from it,
+which changes the string's semantics from byte to character or vice versa. As
+an example, consider the following program and its output:
+
+ $ perl -le'
+ $s1 = "\xC2";
+ $s2 = "\x{2660}";
+ for ($s1, $s2, $s1.$s2) {
+ print /\w/ || 0;
+ }
+ '
+ 0
+ 0
+ 1
+
+If there's no C<\w> in C<s1> or in C<s2>, why does their concatenation have one?
+
+This anomaly stems from Perl's attempt to not disturb older programs that
+didn't use Unicode, and hence had no semantics for characters outside of the
+ASCII range (except in a locale), along with Perl's desire to add Unicode
+support seamlessly. The result wasn't seamless: these characters were
+orphaned.
+
+Work is being done to correct this, but only some of it was complete in time
+for the 5.12 release. What has been finished is the important part of the case
+changing component. Due to concerns, and some evidence, that older code might
+have come to rely on the existing behavior, the new behavior must be explicitly
+enabled by the feature C<unicode_strings> in the L<feature> pragma, even though
+no new syntax is involved.
+
+See L<perlfunc/lc> for details on how this pragma works in combination with
+various others for casing. Even though the pragma only affects casing
+operations in the 5.12 release, it is planned to have it affect all the
+problematic behaviors in later releases: you can't have one without them all.
+
+In the meantime, a workaround is to always call utf8::upgrade($string), or to
+use the standard module L<Encode>. Also, a scalar that has any characters
+whose ordinal is above 0x100, or which were specified using either of the
+C<\N{...}> notations will automatically have character semantics.
+
+=head2 Forcing Unicode in Perl (Or Unforcing Unicode in Perl)
+
+Sometimes (see L</"When Unicode Does Not Happen"> or L</The "Unicode Bug">)
+there are situations where you simply need to force a byte
+string into UTF-8, or vice versa. The low-level calls
+utf8::upgrade($bytestring) and utf8::downgrade($utf8string[, FAIL_OK]) are
+the answers.
+
+Note that utf8::downgrade() can fail if the string contains characters
+that don't fit into a byte.
+
+Calling either function on a string that already is in the desired state is a
+no-op.
+
+=head2 Using Unicode in XS
+
+If you want to handle Perl Unicode in XS extensions, you may find the
+following C APIs useful. See also L<perlguts/"Unicode Support"> for an
+explanation about Unicode at the XS level, and L<perlapi> for the API
+details.
+
+=over 4
+
+=item *
+
+C<DO_UTF8(sv)> returns true if the C<UTF8> flag is on and the bytes
+pragma is not in effect. C<SvUTF8(sv)> returns true if the C<UTF8>
+flag is on; the bytes pragma is ignored. The C<UTF8> flag being on
+does B<not> mean that there are any characters of code points greater
+than 255 (or 127) in the scalar or that there are even any characters
+in the scalar. What the C<UTF8> flag means is that the sequence of
+octets in the representation of the scalar is the sequence of UTF-8
+encoded code points of the characters of a string. The C<UTF8> flag
+being off means that each octet in this representation encodes a
+single character with code point 0..255 within the string. Perl's
+Unicode model is not to use UTF-8 until it is absolutely necessary.
+
+=item *
+
+C<uvchr_to_utf8(buf, chr)> writes a Unicode character code point into
+a buffer encoding the code point as UTF-8, and returns a pointer
+pointing after the UTF-8 bytes. It works appropriately on EBCDIC machines.
+
+=item *
+
+C<utf8_to_uvchr(buf, lenp)> reads UTF-8 encoded bytes from a buffer and
+returns the Unicode character code point and, optionally, the length of
+the UTF-8 byte sequence. It works appropriately on EBCDIC machines.
+
+=item *
+
+C<utf8_length(start, end)> returns the length of the UTF-8 encoded buffer
+in characters. C<sv_len_utf8(sv)> returns the length of the UTF-8 encoded
+scalar.
+
+=item *
+
+C<sv_utf8_upgrade(sv)> converts the string of the scalar to its UTF-8
+encoded form. C<sv_utf8_downgrade(sv)> does the opposite, if
+possible. C<sv_utf8_encode(sv)> is like sv_utf8_upgrade except that
+it does not set the C<UTF8> flag. C<sv_utf8_decode()> does the
+opposite of C<sv_utf8_encode()>. Note that none of these are to be
+used as general-purpose encoding or decoding interfaces: C<use Encode>
+for that. C<sv_utf8_upgrade()> is affected by the encoding pragma
+but C<sv_utf8_downgrade()> is not (since the encoding pragma is
+designed to be a one-way street).
+
+=item *
+
+C<is_utf8_char(s)> returns true if the pointer points to a valid UTF-8
+character.
+
+=item *
+
+C<is_utf8_string(buf, len)> returns true if C<len> bytes of the buffer
+are valid UTF-8.
+
+=item *
+
+C<UTF8SKIP(buf)> will return the number of bytes in the UTF-8 encoded
+character in the buffer. C<UNISKIP(chr)> will return the number of bytes
+required to UTF-8-encode the Unicode character code point. C<UTF8SKIP()>
+is useful for example for iterating over the characters of a UTF-8
+encoded buffer; C<UNISKIP()> is useful, for example, in computing
+the size required for a UTF-8 encoded buffer.
+
+=item *
+
+C<utf8_distance(a, b)> will tell the distance in characters between the
+two pointers pointing to the same UTF-8 encoded buffer.
+
+=item *
+
+C<utf8_hop(s, off)> will return a pointer to a UTF-8 encoded buffer
+that is C<off> (positive or negative) Unicode characters displaced
+from the UTF-8 buffer C<s>. Be careful not to overstep the buffer:
+C<utf8_hop()> will merrily run off the end or the beginning of the
+buffer if told to do so.
+
+=item *
+
+C<pv_uni_display(dsv, spv, len, pvlim, flags)> and
+C<sv_uni_display(dsv, ssv, pvlim, flags)> are useful for debugging the
+output of Unicode strings and scalars. By default they are useful
+only for debugging--they display B<all> characters as hexadecimal code
+points--but with the flags C<UNI_DISPLAY_ISPRINT>,
+C<UNI_DISPLAY_BACKSLASH>, and C<UNI_DISPLAY_QQ> you can make the
+output more readable.
+
+=item *
+
+C<ibcmp_utf8(s1, pe1, l1, u1, s2, pe2, l2, u2)> can be used to
+compare two strings case-insensitively in Unicode. For case-sensitive
+comparisons you can just use C<memEQ()> and C<memNE()> as usual.
+
+=back
+
+For more information, see L<perlapi>, and F<utf8.c> and F<utf8.h>
+in the Perl source code distribution.
+
+=head2 Hacking Perl to work on earlier Unicode versions (for very serious hackers only)
+
+Perl by default comes with the latest supported Unicode version built in, but
+you can change to use any earlier one.
+
+Download the files in the version of Unicode that you want from the Unicode web
+site L<http://www.unicode.org>). These should replace the existing files in
+C<\$Config{privlib}>/F<unicore>. (C<\%Config> is available from the Config
+module.) Follow the instructions in F<README.perl> in that directory to change
+some of their names, and then run F<make>.
+
+It is even possible to download them to a different directory, and then change
+F<utf8_heavy.pl> in the directory C<\$Config{privlib}> to point to the new
+directory, or maybe make a copy of that directory before making the change, and
+using C<@INC> or the C<-I> run-time flag to switch between versions at will
+(but because of caching, not in the middle of a process), but all this is
+beyond the scope of these instructions.
+
+=head1 BUGS
+
+=head2 Interaction with Locales
+
+Use of locales with Unicode data may lead to odd results. Currently,
+Perl attempts to attach 8-bit locale info to characters in the range
+0..255, but this technique is demonstrably incorrect for locales that
+use characters above that range when mapped into Unicode. Perl's
+Unicode support will also tend to run slower. Use of locales with
+Unicode is discouraged.
+
+=head2 Problems with characters in the Latin-1 Supplement range
+
+See L</The "Unicode Bug">
+
+=head2 Problems with case-insensitive regular expression matching
+
+There are problems with case-insensitive matches, including those involving
+character classes (enclosed in [square brackets]), characters whose fold
+is to multiple characters (such as the single character LATIN SMALL LIGATURE
+FFL matches case-insensitively with the 3-character string C<ffl>), and
+characters in the Latin-1 Supplement.
+
+=head2 Interaction with Extensions
+
+When Perl exchanges data with an extension, the extension should be
+able to understand the UTF8 flag and act accordingly. If the
+extension doesn't know about the flag, it's likely that the extension
+will return incorrectly-flagged data.
+
+So if you're working with Unicode data, consult the documentation of
+every module you're using if there are any issues with Unicode data
+exchange. If the documentation does not talk about Unicode at all,
+suspect the worst and probably look at the source to learn how the
+module is implemented. Modules written completely in Perl shouldn't
+cause problems. Modules that directly or indirectly access code written
+in other programming languages are at risk.
+
+For affected functions, the simple strategy to avoid data corruption is
+to always make the encoding of the exchanged data explicit. Choose an
+encoding that you know the extension can handle. Convert arguments passed
+to the extensions to that encoding and convert results back from that
+encoding. Write wrapper functions that do the conversions for you, so
+you can later change the functions when the extension catches up.
+
+To provide an example, let's say the popular Foo::Bar::escape_html
+function doesn't deal with Unicode data yet. The wrapper function
+would convert the argument to raw UTF-8 and convert the result back to
+Perl's internal representation like so:
+
+ sub my_escape_html ($) {
+ my($what) = shift;
+ return unless defined $what;
+ Encode::decode_utf8(Foo::Bar::escape_html(Encode::encode_utf8($what)));
+ }
+
+Sometimes, when the extension does not convert data but just stores
+and retrieves them, you will be in a position to use the otherwise
+dangerous Encode::_utf8_on() function. Let's say the popular
+C<Foo::Bar> extension, written in C, provides a C<param> method that
+lets you store and retrieve data according to these prototypes:
+
+ $self->param($name, $value); # set a scalar
+ $value = $self->param($name); # retrieve a scalar
+
+If it does not yet provide support for any encoding, one could write a
+derived class with such a C<param> method:
+
+ sub param {
+ my($self,$name,$value) = @_;
+ utf8::upgrade($name); # make sure it is UTF-8 encoded
+ if (defined $value) {
+ utf8::upgrade($value); # make sure it is UTF-8 encoded
+ return $self->SUPER::param($name,$value);
+ } else {
+ my $ret = $self->SUPER::param($name);
+ Encode::_utf8_on($ret); # we know, it is UTF-8 encoded
+ return $ret;
+ }
+ }
+
+Some extensions provide filters on data entry/exit points, such as
+DB_File::filter_store_key and family. Look out for such filters in
+the documentation of your extensions, they can make the transition to
+Unicode data much easier.
+
+=head2 Speed
+
+Some functions are slower when working on UTF-8 encoded strings than
+on byte encoded strings. All functions that need to hop over
+characters such as length(), substr() or index(), or matching regular
+expressions can work B<much> faster when the underlying data are
+byte-encoded.
+
+In Perl 5.8.0 the slowness was often quite spectacular; in Perl 5.8.1
+a caching scheme was introduced which will hopefully make the slowness
+somewhat less spectacular, at least for some operations. In general,
+operations with UTF-8 encoded strings are still slower. As an example,
+the Unicode properties (character classes) like C<\p{Nd}> are known to
+be quite a bit slower (5-20 times) than their simpler counterparts
+like C<\d> (then again, there 268 Unicode characters matching C<Nd>
+compared with the 10 ASCII characters matching C<d>).
+
+=head2 Problems on EBCDIC platforms
+
+There are a number of known problems with Perl on EBCDIC platforms. If you
+want to use Perl there, send email to perlbug@perl.org.
+
+In earlier versions, when byte and character data were concatenated,
+the new string was sometimes created by
+decoding the byte strings as I<ISO 8859-1 (Latin-1)>, even if the
+old Unicode string used EBCDIC.
+
+If you find any of these, please report them as bugs.
+
+=head2 Porting code from perl-5.6.X
+
+Perl 5.8 has a different Unicode model from 5.6. In 5.6 the programmer
+was required to use the C<utf8> pragma to declare that a given scope
+expected to deal with Unicode data and had to make sure that only
+Unicode data were reaching that scope. If you have code that is
+working with 5.6, you will need some of the following adjustments to
+your code. The examples are written such that the code will continue
+to work under 5.6, so you should be safe to try them out.
+
+=over 4
+
+=item *
+
+A filehandle that should read or write UTF-8
+
+ if ($] > 5.007) {
+ binmode $fh, ":encoding(utf8)";
+ }
+
+=item *
+
+A scalar that is going to be passed to some extension
+
+Be it Compress::Zlib, Apache::Request or any extension that has no
+mention of Unicode in the manpage, you need to make sure that the
+UTF8 flag is stripped off. Note that at the time of this writing
+(October 2002) the mentioned modules are not UTF-8-aware. Please
+check the documentation to verify if this is still true.
+
+ if ($] > 5.007) {
+ require Encode;
+ $val = Encode::encode_utf8($val); # make octets
+ }
+
+=item *
+
+A scalar we got back from an extension
+
+If you believe the scalar comes back as UTF-8, you will most likely
+want the UTF8 flag restored:
+
+ if ($] > 5.007) {
+ require Encode;
+ $val = Encode::decode_utf8($val);
+ }
+
+=item *
+
+Same thing, if you are really sure it is UTF-8
+
+ if ($] > 5.007) {
+ require Encode;
+ Encode::_utf8_on($val);
+ }
+
+=item *
+
+A wrapper for fetchrow_array and fetchrow_hashref
+
+When the database contains only UTF-8, a wrapper function or method is
+a convenient way to replace all your fetchrow_array and
+fetchrow_hashref calls. A wrapper function will also make it easier to
+adapt to future enhancements in your database driver. Note that at the
+time of this writing (October 2002), the DBI has no standardized way
+to deal with UTF-8 data. Please check the documentation to verify if
+that is still true.
+
+ sub fetchrow {
+ my($self, $sth, $what) = @_; # $what is one of fetchrow_{array,hashref}
+ if ($] < 5.007) {
+ return $sth->$what;
+ } else {
+ require Encode;
+ if (wantarray) {
+ my @arr = $sth->$what;
+ for (@arr) {
+ defined && /[^\000-\177]/ && Encode::_utf8_on($_);
+ }
+ return @arr;
+ } else {
+ my $ret = $sth->$what;
+ if (ref $ret) {
+ for my $k (keys %$ret) {
+ defined && /[^\000-\177]/ && Encode::_utf8_on($_) for $ret->{$k};
+ }
+ return $ret;
+ } else {
+ defined && /[^\000-\177]/ && Encode::_utf8_on($_) for $ret;
+ return $ret;
+ }
+ }
+ }
+ }
+
+
+=item *
+
+A large scalar that you know can only contain ASCII
+
+Scalars that contain only ASCII and are marked as UTF-8 are sometimes
+a drag to your program. If you recognize such a situation, just remove
+the UTF8 flag:
+
+ utf8::downgrade($val) if $] > 5.007;
+
+=back
+
+=head1 SEE ALSO
+
+L<perlunitut>, L<perluniintro>, L<perluniprops>, L<Encode>, L<open>, L<utf8>, L<bytes>,
+L<perlretut>, L<perlvar/"${^UNICODE}">
+L<http://www.unicode.org/reports/tr44>).
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlunifaq.pod b/Master/tlpkg/tlperl/lib/pods/perlunifaq.pod
new file mode 100644
index 00000000000..ab42ff194a0
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlunifaq.pod
@@ -0,0 +1,319 @@
+=head1 NAME
+
+perlunifaq - Perl Unicode FAQ
+
+=head1 Q and A
+
+This is a list of questions and answers about Unicode in Perl, intended to be
+read after L<perlunitut>.
+
+=head2 perlunitut isn't really a Unicode tutorial, is it?
+
+No, and this isn't really a Unicode FAQ.
+
+Perl has an abstracted interface for all supported character encodings, so this
+is actually a generic C<Encode> tutorial and C<Encode> FAQ. But many people
+think that Unicode is special and magical, and I didn't want to disappoint
+them, so I decided to call the document a Unicode tutorial.
+
+=head2 What character encodings does Perl support?
+
+To find out which character encodings your Perl supports, run:
+
+ perl -MEncode -le "print for Encode->encodings(':all')"
+
+=head2 Which version of perl should I use?
+
+Well, if you can, upgrade to the most recent, but certainly C<5.8.1> or newer.
+The tutorial and FAQ assume the latest release.
+
+You should also check your modules, and upgrade them if necessary. For example,
+HTML::Entities requires version >= 1.32 to function correctly, even though the
+changelog is silent about this.
+
+=head2 What about binary data, like images?
+
+Well, apart from a bare C<binmode $fh>, you shouldn't treat them specially.
+(The binmode is needed because otherwise Perl may convert line endings on Win32
+systems.)
+
+Be careful, though, to never combine text strings with binary strings. If you
+need text in a binary stream, encode your text strings first using the
+appropriate encoding, then join them with binary strings. See also: "What if I
+don't encode?".
+
+=head2 When should I decode or encode?
+
+Whenever you're communicating text with anything that is external to your perl
+process, like a database, a text file, a socket, or another program. Even if
+the thing you're communicating with is also written in Perl.
+
+=head2 What if I don't decode?
+
+Whenever your encoded, binary string is used together with a text string, Perl
+will assume that your binary string was encoded with ISO-8859-1, also known as
+latin-1. If it wasn't latin-1, then your data is unpleasantly converted. For
+example, if it was UTF-8, the individual bytes of multibyte characters are seen
+as separate characters, and then again converted to UTF-8. Such double encoding
+can be compared to double HTML encoding (C<&amp;gt;>), or double URI encoding
+(C<%253E>).
+
+This silent implicit decoding is known as "upgrading". That may sound
+positive, but it's best to avoid it.
+
+=head2 What if I don't encode?
+
+Your text string will be sent using the bytes in Perl's internal format. In
+some cases, Perl will warn you that you're doing something wrong, with a
+friendly warning:
+
+ Wide character in print at example.pl line 2.
+
+Because the internal format is often UTF-8, these bugs are hard to spot,
+because UTF-8 is usually the encoding you wanted! But don't be lazy, and don't
+use the fact that Perl's internal format is UTF-8 to your advantage. Encode
+explicitly to avoid weird bugs, and to show to maintenance programmers that you
+thought this through.
+
+=head2 Is there a way to automatically decode or encode?
+
+If all data that comes from a certain handle is encoded in exactly the same
+way, you can tell the PerlIO system to automatically decode everything, with
+the C<encoding> layer. If you do this, you can't accidentally forget to decode
+or encode anymore, on things that use the layered handle.
+
+You can provide this layer when C<open>ing the file:
+
+ open my $fh, '>:encoding(UTF-8)', $filename; # auto encoding on write
+ open my $fh, '<:encoding(UTF-8)', $filename; # auto decoding on read
+
+Or if you already have an open filehandle:
+
+ binmode $fh, ':encoding(UTF-8)';
+
+Some database drivers for DBI can also automatically encode and decode, but
+that is sometimes limited to the UTF-8 encoding.
+
+=head2 What if I don't know which encoding was used?
+
+Do whatever you can to find out, and if you have to: guess. (Don't forget to
+document your guess with a comment.)
+
+You could open the document in a web browser, and change the character set or
+character encoding until you can visually confirm that all characters look the
+way they should.
+
+There is no way to reliably detect the encoding automatically, so if people
+keep sending you data without charset indication, you may have to educate them.
+
+=head2 Can I use Unicode in my Perl sources?
+
+Yes, you can! If your sources are UTF-8 encoded, you can indicate that with the
+C<use utf8> pragma.
+
+ use utf8;
+
+This doesn't do anything to your input, or to your output. It only influences
+the way your sources are read. You can use Unicode in string literals, in
+identifiers (but they still have to be "word characters" according to C<\w>),
+and even in custom delimiters.
+
+=head2 Data::Dumper doesn't restore the UTF8 flag; is it broken?
+
+No, Data::Dumper's Unicode abilities are as they should be. There have been
+some complaints that it should restore the UTF8 flag when the data is read
+again with C<eval>. However, you should really not look at the flag, and
+nothing indicates that Data::Dumper should break this rule.
+
+Here's what happens: when Perl reads in a string literal, it sticks to 8 bit
+encoding as long as it can. (But perhaps originally it was internally encoded
+as UTF-8, when you dumped it.) When it has to give that up because other
+characters are added to the text string, it silently upgrades the string to
+UTF-8.
+
+If you properly encode your strings for output, none of this is of your
+concern, and you can just C<eval> dumped data as always.
+
+=head2 Why do regex character classes sometimes match only in the ASCII range?
+
+=head2 Why do some characters not uppercase or lowercase correctly?
+
+It seemed like a good idea at the time, to keep the semantics the same for
+standard strings, when Perl got Unicode support. The plan is to fix this
+in the future, and the casing component has in fact mostly been fixed, but we
+have to deal with the fact that Perl treats equal strings differently,
+depending on the internal state.
+
+First the casing. Just put a C<use feature 'unicode_strings'> near the
+beginning of your program. Within its lexical scope, C<uc>, C<lc>, C<ucfirst>,
+C<lcfirst>, and the regular expression escapes C<\U>, C<\L>, C<\u>, C<\l> use
+Unicode semantics for changing case regardless of whether the UTF8 flag is on
+or not. However, if you pass strings to subroutines in modules outside the
+pragma's scope, they currently likely won't behave this way, and you have to
+try one of the solutions below. There is another exception as well: if you
+have furnished your own casing functions to override the default, these will
+not be called unless the UTF8 flag is on)
+
+This remains a problem for the regular expression constructs
+C<\d>, C<\s>, C<\w>, C<\D>, C<\S>, C<\W>, C</.../i>, C<(?i:...)>,
+and C</[[:posix:]]/>.
+
+To force Unicode semantics, you can upgrade the internal representation to
+by doing C<utf8::upgrade($string)>. This can be used
+safely on any string, as it checks and does not change strings that have
+already been upgraded.
+
+For a more detailed discussion, see L<Unicode::Semantics> on CPAN.
+
+=head2 How can I determine if a string is a text string or a binary string?
+
+You can't. Some use the UTF8 flag for this, but that's misuse, and makes well
+behaved modules like Data::Dumper look bad. The flag is useless for this
+purpose, because it's off when an 8 bit encoding (by default ISO-8859-1) is
+used to store the string.
+
+This is something you, the programmer, has to keep track of; sorry. You could
+consider adopting a kind of "Hungarian notation" to help with this.
+
+=head2 How do I convert from encoding FOO to encoding BAR?
+
+By first converting the FOO-encoded byte string to a text string, and then the
+text string to a BAR-encoded byte string:
+
+ my $text_string = decode('FOO', $foo_string);
+ my $bar_string = encode('BAR', $text_string);
+
+or by skipping the text string part, and going directly from one binary
+encoding to the other:
+
+ use Encode qw(from_to);
+ from_to($string, 'FOO', 'BAR'); # changes contents of $string
+
+or by letting automatic decoding and encoding do all the work:
+
+ open my $foofh, '<:encoding(FOO)', 'example.foo.txt';
+ open my $barfh, '>:encoding(BAR)', 'example.bar.txt';
+ print { $barfh } $_ while <$foofh>;
+
+=head2 What are C<decode_utf8> and C<encode_utf8>?
+
+These are alternate syntaxes for C<decode('utf8', ...)> and C<encode('utf8',
+...)>.
+
+=head2 What is a "wide character"?
+
+This is a term used both for characters with an ordinal value greater than 127,
+characters with an ordinal value greater than 255, or any character occupying
+more than one byte, depending on the context.
+
+The Perl warning "Wide character in ..." is caused by a character with an
+ordinal value greater than 255. With no specified encoding layer, Perl tries to
+fit things in ISO-8859-1 for backward compatibility reasons. When it can't, it
+emits this warning (if warnings are enabled), and outputs UTF-8 encoded data
+instead.
+
+To avoid this warning and to avoid having different output encodings in a single
+stream, always specify an encoding explicitly, for example with a PerlIO layer:
+
+ binmode STDOUT, ":encoding(UTF-8)";
+
+=head1 INTERNALS
+
+=head2 What is "the UTF8 flag"?
+
+Please, unless you're hacking the internals, or debugging weirdness, don't
+think about the UTF8 flag at all. That means that you very probably shouldn't
+use C<is_utf8>, C<_utf8_on> or C<_utf8_off> at all.
+
+The UTF8 flag, also called SvUTF8, is an internal flag that indicates that the
+current internal representation is UTF-8. Without the flag, it is assumed to be
+ISO-8859-1. Perl converts between these automatically. (Actually Perl usually
+assumes the representation is ASCII; see L</Why do regex character classes
+sometimes match only in the ASCII range?> above.)
+
+One of Perl's internal formats happens to be UTF-8. Unfortunately, Perl can't
+keep a secret, so everyone knows about this. That is the source of much
+confusion. It's better to pretend that the internal format is some unknown
+encoding, and that you always have to encode and decode explicitly.
+
+=head2 What about the C<use bytes> pragma?
+
+Don't use it. It makes no sense to deal with bytes in a text string, and it
+makes no sense to deal with characters in a byte string. Do the proper
+conversions (by decoding/encoding), and things will work out well: you get
+character counts for decoded data, and byte counts for encoded data.
+
+C<use bytes> is usually a failed attempt to do something useful. Just forget
+about it.
+
+=head2 What about the C<use encoding> pragma?
+
+Don't use it. Unfortunately, it assumes that the programmer's environment and
+that of the user will use the same encoding. It will use the same encoding for
+the source code and for STDIN and STDOUT. When a program is copied to another
+machine, the source code does not change, but the STDIO environment might.
+
+If you need non-ASCII characters in your source code, make it a UTF-8 encoded
+file and C<use utf8>.
+
+If you need to set the encoding for STDIN, STDOUT, and STDERR, for example
+based on the user's locale, C<use open>.
+
+=head2 What is the difference between C<:encoding> and C<:utf8>?
+
+Because UTF-8 is one of Perl's internal formats, you can often just skip the
+encoding or decoding step, and manipulate the UTF8 flag directly.
+
+Instead of C<:encoding(UTF-8)>, you can simply use C<:utf8>, which skips the
+encoding step if the data was already represented as UTF8 internally. This is
+widely accepted as good behavior when you're writing, but it can be dangerous
+when reading, because it causes internal inconsistency when you have invalid
+byte sequences. Using C<:utf8> for input can sometimes result in security
+breaches, so please use C<:encoding(UTF-8)> instead.
+
+Instead of C<decode> and C<encode>, you could use C<_utf8_on> and C<_utf8_off>,
+but this is considered bad style. Especially C<_utf8_on> can be dangerous, for
+the same reason that C<:utf8> can.
+
+There are some shortcuts for oneliners; see C<-C> in L<perlrun>.
+
+=head2 What's the difference between C<UTF-8> and C<utf8>?
+
+C<UTF-8> is the official standard. C<utf8> is Perl's way of being liberal in
+what it accepts. If you have to communicate with things that aren't so liberal,
+you may want to consider using C<UTF-8>. If you have to communicate with things
+that are too liberal, you may have to use C<utf8>. The full explanation is in
+L<Encode>.
+
+C<UTF-8> is internally known as C<utf-8-strict>. The tutorial uses UTF-8
+consistently, even where utf8 is actually used internally, because the
+distinction can be hard to make, and is mostly irrelevant.
+
+For example, utf8 can be used for code points that don't exist in Unicode, like
+9999999, but if you encode that to UTF-8, you get a substitution character (by
+default; see L<Encode/"Handling Malformed Data"> for more ways of dealing with
+this.)
+
+Okay, if you insist: the "internal format" is utf8, not UTF-8. (When it's not
+some other encoding.)
+
+=head2 I lost track; what encoding is the internal format really?
+
+It's good that you lost track, because you shouldn't depend on the internal
+format being any specific encoding. But since you asked: by default, the
+internal format is either ISO-8859-1 (latin-1), or utf8, depending on the
+history of the string. On EBCDIC platforms, this may be different even.
+
+Perl knows how it stored the string internally, and will use that knowledge
+when you C<encode>. In other words: don't try to find out what the internal
+encoding for a certain string is, but instead just encode it into the encoding
+that you want.
+
+=head1 AUTHOR
+
+Juerd Waalboer <#####@juerd.nl>
+
+=head1 SEE ALSO
+
+L<perlunicode>, L<perluniintro>, L<Encode>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perluniintro.pod b/Master/tlpkg/tlperl/lib/pods/perluniintro.pod
new file mode 100644
index 00000000000..bee286f5eaa
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perluniintro.pod
@@ -0,0 +1,892 @@
+=head1 NAME
+
+perluniintro - Perl Unicode introduction
+
+=head1 DESCRIPTION
+
+This document gives a general idea of Unicode and how to use Unicode
+in Perl.
+
+=head2 Unicode
+
+Unicode is a character set standard which plans to codify all of the
+writing systems of the world, plus many other symbols.
+
+Unicode and ISO/IEC 10646 are coordinated standards that provide code
+points for characters in almost all modern character set standards,
+covering more than 30 writing systems and hundreds of languages,
+including all commercially-important modern languages. All characters
+in the largest Chinese, Japanese, and Korean dictionaries are also
+encoded. The standards will eventually cover almost all characters in
+more than 250 writing systems and thousands of languages.
+Unicode 1.0 was released in October 1991, and 4.0 in April 2003.
+
+A Unicode I<character> is an abstract entity. It is not bound to any
+particular integer width, especially not to the C language C<char>.
+Unicode is language-neutral and display-neutral: it does not encode the
+language of the text, and it does not generally define fonts or other graphical
+layout details. Unicode operates on characters and on text built from
+those characters.
+
+Unicode defines characters like C<LATIN CAPITAL LETTER A> or C<GREEK
+SMALL LETTER ALPHA> and unique numbers for the characters, in this
+case 0x0041 and 0x03B1, respectively. These unique numbers are called
+I<code points>.
+
+The Unicode standard prefers using hexadecimal notation for the code
+points. If numbers like C<0x0041> are unfamiliar to you, take a peek
+at a later section, L</"Hexadecimal Notation">. The Unicode standard
+uses the notation C<U+0041 LATIN CAPITAL LETTER A>, to give the
+hexadecimal code point and the normative name of the character.
+
+Unicode also defines various I<properties> for the characters, like
+"uppercase" or "lowercase", "decimal digit", or "punctuation";
+these properties are independent of the names of the characters.
+Furthermore, various operations on the characters like uppercasing,
+lowercasing, and collating (sorting) are defined.
+
+A Unicode I<logical> "character" can actually consist of more than one internal
+I<actual> "character" or code point. For Western languages, this is adequately
+modelled by a I<base character> (like C<LATIN CAPITAL LETTER A>) followed
+by one or more I<modifiers> (like C<COMBINING ACUTE ACCENT>). This sequence of
+base character and modifiers is called a I<combining character
+sequence>. Some non-western languages require more complicated
+models, so Unicode created the I<grapheme cluster> concept, and then the
+I<extended grapheme cluster>. For example, a Korean Hangul syllable is
+considered a single logical character, but most often consists of three actual
+Unicode characters: a leading consonant followed by an interior vowel followed
+by a trailing consonant.
+
+Whether to call these extended grapheme clusters "characters" depends on your
+point of view. If you are a programmer, you probably would tend towards seeing
+each element in the sequences as one unit, or "character". The whole sequence
+could be seen as one "character", however, from the user's point of view, since
+that's probably what it looks like in the context of the user's language.
+
+With this "whole sequence" view of characters, the total number of
+characters is open-ended. But in the programmer's "one unit is one
+character" point of view, the concept of "characters" is more
+deterministic. In this document, we take that second point of view:
+one "character" is one Unicode code point.
+
+For some combinations, there are I<precomposed> characters.
+C<LATIN CAPITAL LETTER A WITH ACUTE>, for example, is defined as
+a single code point. These precomposed characters are, however,
+only available for some combinations, and are mainly
+meant to support round-trip conversions between Unicode and legacy
+standards (like the ISO 8859). In the general case, the composing
+method is more extensible. To support conversion between
+different compositions of the characters, various I<normalization
+forms> to standardize representations are also defined.
+
+Because of backward compatibility with legacy encodings, the "a unique
+number for every character" idea breaks down a bit: instead, there is
+"at least one number for every character". The same character could
+be represented differently in several legacy encodings. The
+converse is also not true: some code points do not have an assigned
+character. Firstly, there are unallocated code points within
+otherwise used blocks. Secondly, there are special Unicode control
+characters that do not represent true characters.
+
+A common myth about Unicode is that it is "16-bit", that is,
+Unicode is only represented as C<0x10000> (or 65536) characters from
+C<0x0000> to C<0xFFFF>. B<This is untrue.> Since Unicode 2.0 (July
+1996), Unicode has been defined all the way up to 21 bits (C<0x10FFFF>),
+and since Unicode 3.1 (March 2001), characters have been defined
+beyond C<0xFFFF>. The first C<0x10000> characters are called the
+I<Plane 0>, or the I<Basic Multilingual Plane> (BMP). With Unicode
+3.1, 17 (yes, seventeen) planes in all were defined--but they are
+nowhere near full of defined characters, yet.
+
+Another myth is about Unicode blocks--that they have something to
+do with languages--that each block would define the characters used
+by a language or a set of languages. B<This is also untrue.>
+The division into blocks exists, but it is almost completely
+accidental--an artifact of how the characters have been and
+still are allocated. Instead, there is a concept called I<scripts>, which is
+more useful: there is C<Latin> script, C<Greek> script, and so on. Scripts
+usually span varied parts of several blocks. For more information about
+scripts, see L<perlunicode/Scripts>.
+
+The Unicode code points are just abstract numbers. To input and
+output these abstract numbers, the numbers must be I<encoded> or
+I<serialised> somehow. Unicode defines several I<character encoding
+forms>, of which I<UTF-8> is perhaps the most popular. UTF-8 is a
+variable length encoding that encodes Unicode characters as 1 to 6
+bytes. Other encodings
+include UTF-16 and UTF-32 and their big- and little-endian variants
+(UTF-8 is byte-order independent) The ISO/IEC 10646 defines the UCS-2
+and UCS-4 encoding forms.
+
+For more information about encodings--for instance, to learn what
+I<surrogates> and I<byte order marks> (BOMs) are--see L<perlunicode>.
+
+=head2 Perl's Unicode Support
+
+Starting from Perl 5.6.0, Perl has had the capacity to handle Unicode
+natively. Perl 5.8.0, however, is the first recommended release for
+serious Unicode work. The maintenance release 5.6.1 fixed many of the
+problems of the initial Unicode implementation, but for example
+regular expressions still do not work with Unicode in 5.6.1.
+
+B<Starting from Perl 5.8.0, the use of C<use utf8> is needed only in much more restricted circumstances.> In earlier releases the C<utf8> pragma was used to declare
+that operations in the current block or file would be Unicode-aware.
+This model was found to be wrong, or at least clumsy: the "Unicodeness"
+is now carried with the data, instead of being attached to the
+operations. Only one case remains where an explicit C<use utf8> is
+needed: if your Perl script itself is encoded in UTF-8, you can use
+UTF-8 in your identifier names, and in string and regular expression
+literals, by saying C<use utf8>. This is not the default because
+scripts with legacy 8-bit data in them would break. See L<utf8>.
+
+=head2 Perl's Unicode Model
+
+Perl supports both pre-5.6 strings of eight-bit native bytes, and
+strings of Unicode characters. The principle is that Perl tries to
+keep its data as eight-bit bytes for as long as possible, but as soon
+as Unicodeness cannot be avoided, the data is (mostly) transparently upgraded
+to Unicode. There are some problems--see L<perlunicode/The "Unicode Bug">.
+
+Internally, Perl currently uses either whatever the native eight-bit
+character set of the platform (for example Latin-1) is, defaulting to
+UTF-8, to encode Unicode strings. Specifically, if all code points in
+the string are C<0xFF> or less, Perl uses the native eight-bit
+character set. Otherwise, it uses UTF-8.
+
+A user of Perl does not normally need to know nor care how Perl
+happens to encode its internal strings, but it becomes relevant when
+outputting Unicode strings to a stream without a PerlIO layer (one with
+the "default" encoding). In such a case, the raw bytes used internally
+(the native character set or UTF-8, as appropriate for each string)
+will be used, and a "Wide character" warning will be issued if those
+strings contain a character beyond 0x00FF.
+
+For example,
+
+ perl -e 'print "\x{DF}\n", "\x{0100}\x{DF}\n"'
+
+produces a fairly useless mixture of native bytes and UTF-8, as well
+as a warning:
+
+ Wide character in print at ...
+
+To output UTF-8, use the C<:encoding> or C<:utf8> output layer. Prepending
+
+ binmode(STDOUT, ":utf8");
+
+to this sample program ensures that the output is completely UTF-8,
+and removes the program's warning.
+
+You can enable automatic UTF-8-ification of your standard file
+handles, default C<open()> layer, and C<@ARGV> by using either
+the C<-C> command line switch or the C<PERL_UNICODE> environment
+variable, see L<perlrun> for the documentation of the C<-C> switch.
+
+Note that this means that Perl expects other software to work, too:
+if Perl has been led to believe that STDIN should be UTF-8, but then
+STDIN coming in from another command is not UTF-8, Perl will complain
+about the malformed UTF-8.
+
+All features that combine Unicode and I/O also require using the new
+PerlIO feature. Almost all Perl 5.8 platforms do use PerlIO, though:
+you can see whether yours is by running "perl -V" and looking for
+C<useperlio=define>.
+
+=head2 Unicode and EBCDIC
+
+Perl 5.8.0 also supports Unicode on EBCDIC platforms. There,
+Unicode support is somewhat more complex to implement since
+additional conversions are needed at every step.
+
+Later Perl releases have added code that will not work on EBCDIC platforms, and
+no one has complained, so the divergence has continued. If you want to run
+Perl on an EBCDIC platform, send email to perlbug@perl.org
+
+On EBCDIC platforms, the internal Unicode encoding form is UTF-EBCDIC
+instead of UTF-8. The difference is that as UTF-8 is "ASCII-safe" in
+that ASCII characters encode to UTF-8 as-is, while UTF-EBCDIC is
+"EBCDIC-safe".
+
+=head2 Creating Unicode
+
+To create Unicode characters in literals for code points above C<0xFF>,
+use the C<\x{...}> notation in double-quoted strings:
+
+ my $smiley = "\x{263a}";
+
+Similarly, it can be used in regular expression literals
+
+ $smiley =~ /\x{263a}/;
+
+At run-time you can use C<chr()>:
+
+ my $hebrew_alef = chr(0x05d0);
+
+See L</"Further Resources"> for how to find all these numeric codes.
+
+Naturally, C<ord()> will do the reverse: it turns a character into
+a code point.
+
+Note that C<\x..> (no C<{}> and only two hexadecimal digits), C<\x{...}>,
+and C<chr(...)> for arguments less than C<0x100> (decimal 256)
+generate an eight-bit character for backward compatibility with older
+Perls. For arguments of C<0x100> or more, Unicode characters are
+always produced. If you want to force the production of Unicode
+characters regardless of the numeric value, use C<pack("U", ...)>
+instead of C<\x..>, C<\x{...}>, or C<chr()>.
+
+You can also use the C<charnames> pragma to invoke characters
+by name in double-quoted strings:
+
+ use charnames ':full';
+ my $arabic_alef = "\N{ARABIC LETTER ALEF}";
+
+And, as mentioned above, you can also C<pack()> numbers into Unicode
+characters:
+
+ my $georgian_an = pack("U", 0x10a0);
+
+Note that both C<\x{...}> and C<\N{...}> are compile-time string
+constants: you cannot use variables in them. if you want similar
+run-time functionality, use C<chr()> and C<charnames::vianame()>.
+
+If you want to force the result to Unicode characters, use the special
+C<"U0"> prefix. It consumes no arguments but causes the following bytes
+to be interpreted as the UTF-8 encoding of Unicode characters:
+
+ my $chars = pack("U0W*", 0x80, 0x42);
+
+Likewise, you can stop such UTF-8 interpretation by using the special
+C<"C0"> prefix.
+
+=head2 Handling Unicode
+
+Handling Unicode is for the most part transparent: just use the
+strings as usual. Functions like C<index()>, C<length()>, and
+C<substr()> will work on the Unicode characters; regular expressions
+will work on the Unicode characters (see L<perlunicode> and L<perlretut>).
+
+Note that Perl considers grapheme clusters to be separate characters, so for
+example
+
+ use charnames ':full';
+ print length("\N{LATIN CAPITAL LETTER A}\N{COMBINING ACUTE ACCENT}"), "\n";
+
+will print 2, not 1. The only exception is that regular expressions
+have C<\X> for matching an extended grapheme cluster.
+
+Life is not quite so transparent, however, when working with legacy
+encodings, I/O, and certain special cases:
+
+=head2 Legacy Encodings
+
+When you combine legacy data and Unicode the legacy data needs
+to be upgraded to Unicode. Normally ISO 8859-1 (or EBCDIC, if
+applicable) is assumed.
+
+The C<Encode> module knows about many encodings and has interfaces
+for doing conversions between those encodings:
+
+ use Encode 'decode';
+ $data = decode("iso-8859-3", $data); # convert from legacy to utf-8
+
+=head2 Unicode I/O
+
+Normally, writing out Unicode data
+
+ print FH $some_string_with_unicode, "\n";
+
+produces raw bytes that Perl happens to use to internally encode the
+Unicode string. Perl's internal encoding depends on the system as
+well as what characters happen to be in the string at the time. If
+any of the characters are at code points C<0x100> or above, you will get
+a warning. To ensure that the output is explicitly rendered in the
+encoding you desire--and to avoid the warning--open the stream with
+the desired encoding. Some examples:
+
+ open FH, ">:utf8", "file";
+
+ open FH, ">:encoding(ucs2)", "file";
+ open FH, ">:encoding(UTF-8)", "file";
+ open FH, ">:encoding(shift_jis)", "file";
+
+and on already open streams, use C<binmode()>:
+
+ binmode(STDOUT, ":utf8");
+
+ binmode(STDOUT, ":encoding(ucs2)");
+ binmode(STDOUT, ":encoding(UTF-8)");
+ binmode(STDOUT, ":encoding(shift_jis)");
+
+The matching of encoding names is loose: case does not matter, and
+many encodings have several aliases. Note that the C<:utf8> layer
+must always be specified exactly like that; it is I<not> subject to
+the loose matching of encoding names. Also note that C<:utf8> is unsafe for
+input, because it accepts the data without validating that it is indeed valid
+UTF8.
+
+See L<PerlIO> for the C<:utf8> layer, L<PerlIO::encoding> and
+L<Encode::PerlIO> for the C<:encoding()> layer, and
+L<Encode::Supported> for many encodings supported by the C<Encode>
+module.
+
+Reading in a file that you know happens to be encoded in one of the
+Unicode or legacy encodings does not magically turn the data into
+Unicode in Perl's eyes. To do that, specify the appropriate
+layer when opening files
+
+ open(my $fh,'<:encoding(utf8)', 'anything');
+ my $line_of_unicode = <$fh>;
+
+ open(my $fh,'<:encoding(Big5)', 'anything');
+ my $line_of_unicode = <$fh>;
+
+The I/O layers can also be specified more flexibly with
+the C<open> pragma. See L<open>, or look at the following example.
+
+ use open ':encoding(utf8)'; # input/output default encoding will be UTF-8
+ open X, ">file";
+ print X chr(0x100), "\n";
+ close X;
+ open Y, "<file";
+ printf "%#x\n", ord(<Y>); # this should print 0x100
+ close Y;
+
+With the C<open> pragma you can use the C<:locale> layer
+
+ BEGIN { $ENV{LC_ALL} = $ENV{LANG} = 'ru_RU.KOI8-R' }
+ # the :locale will probe the locale environment variables like LC_ALL
+ use open OUT => ':locale'; # russki parusski
+ open(O, ">koi8");
+ print O chr(0x430); # Unicode CYRILLIC SMALL LETTER A = KOI8-R 0xc1
+ close O;
+ open(I, "<koi8");
+ printf "%#x\n", ord(<I>), "\n"; # this should print 0xc1
+ close I;
+
+These methods install a transparent filter on the I/O stream that
+converts data from the specified encoding when it is read in from the
+stream. The result is always Unicode.
+
+The L<open> pragma affects all the C<open()> calls after the pragma by
+setting default layers. If you want to affect only certain
+streams, use explicit layers directly in the C<open()> call.
+
+You can switch encodings on an already opened stream by using
+C<binmode()>; see L<perlfunc/binmode>.
+
+The C<:locale> does not currently (as of Perl 5.8.0) work with
+C<open()> and C<binmode()>, only with the C<open> pragma. The
+C<:utf8> and C<:encoding(...)> methods do work with all of C<open()>,
+C<binmode()>, and the C<open> pragma.
+
+Similarly, you may use these I/O layers on output streams to
+automatically convert Unicode to the specified encoding when it is
+written to the stream. For example, the following snippet copies the
+contents of the file "text.jis" (encoded as ISO-2022-JP, aka JIS) to
+the file "text.utf8", encoded as UTF-8:
+
+ open(my $nihongo, '<:encoding(iso-2022-jp)', 'text.jis');
+ open(my $unicode, '>:utf8', 'text.utf8');
+ while (<$nihongo>) { print $unicode $_ }
+
+The naming of encodings, both by the C<open()> and by the C<open>
+pragma allows for flexible names: C<koi8-r> and C<KOI8R> will both be
+understood.
+
+Common encodings recognized by ISO, MIME, IANA, and various other
+standardisation organisations are recognised; for a more detailed
+list see L<Encode::Supported>.
+
+C<read()> reads characters and returns the number of characters.
+C<seek()> and C<tell()> operate on byte counts, as do C<sysread()>
+and C<sysseek()>.
+
+Notice that because of the default behaviour of not doing any
+conversion upon input if there is no default layer,
+it is easy to mistakenly write code that keeps on expanding a file
+by repeatedly encoding the data:
+
+ # BAD CODE WARNING
+ open F, "file";
+ local $/; ## read in the whole file of 8-bit characters
+ $t = <F>;
+ close F;
+ open F, ">:encoding(utf8)", "file";
+ print F $t; ## convert to UTF-8 on output
+ close F;
+
+If you run this code twice, the contents of the F<file> will be twice
+UTF-8 encoded. A C<use open ':encoding(utf8)'> would have avoided the
+bug, or explicitly opening also the F<file> for input as UTF-8.
+
+B<NOTE>: the C<:utf8> and C<:encoding> features work only if your
+Perl has been built with the new PerlIO feature (which is the default
+on most systems).
+
+=head2 Displaying Unicode As Text
+
+Sometimes you might want to display Perl scalars containing Unicode as
+simple ASCII (or EBCDIC) text. The following subroutine converts
+its argument so that Unicode characters with code points greater than
+255 are displayed as C<\x{...}>, control characters (like C<\n>) are
+displayed as C<\x..>, and the rest of the characters as themselves:
+
+ sub nice_string {
+ join("",
+ map { $_ > 255 ? # if wide character...
+ sprintf("\\x{%04X}", $_) : # \x{...}
+ chr($_) =~ /[[:cntrl:]]/ ? # else if control character ...
+ sprintf("\\x%02X", $_) : # \x..
+ quotemeta(chr($_)) # else quoted or as themselves
+ } unpack("W*", $_[0])); # unpack Unicode characters
+ }
+
+For example,
+
+ nice_string("foo\x{100}bar\n")
+
+returns the string
+
+ 'foo\x{0100}bar\x0A'
+
+which is ready to be printed.
+
+=head2 Special Cases
+
+=over 4
+
+=item *
+
+Bit Complement Operator ~ And vec()
+
+The bit complement operator C<~> may produce surprising results if
+used on strings containing characters with ordinal values above
+255. In such a case, the results are consistent with the internal
+encoding of the characters, but not with much else. So don't do
+that. Similarly for C<vec()>: you will be operating on the
+internally-encoded bit patterns of the Unicode characters, not on
+the code point values, which is very probably not what you want.
+
+=item *
+
+Peeking At Perl's Internal Encoding
+
+Normal users of Perl should never care how Perl encodes any particular
+Unicode string (because the normal ways to get at the contents of a
+string with Unicode--via input and output--should always be via
+explicitly-defined I/O layers). But if you must, there are two
+ways of looking behind the scenes.
+
+One way of peeking inside the internal encoding of Unicode characters
+is to use C<unpack("C*", ...> to get the bytes of whatever the string
+encoding happens to be, or C<unpack("U0..", ...)> to get the bytes of the
+UTF-8 encoding:
+
+ # this prints c4 80 for the UTF-8 bytes 0xc4 0x80
+ print join(" ", unpack("U0(H2)*", pack("U", 0x100))), "\n";
+
+Yet another way would be to use the Devel::Peek module:
+
+ perl -MDevel::Peek -e 'Dump(chr(0x100))'
+
+That shows the C<UTF8> flag in FLAGS and both the UTF-8 bytes
+and Unicode characters in C<PV>. See also later in this document
+the discussion about the C<utf8::is_utf8()> function.
+
+=back
+
+=head2 Advanced Topics
+
+=over 4
+
+=item *
+
+String Equivalence
+
+The question of string equivalence turns somewhat complicated
+in Unicode: what do you mean by "equal"?
+
+(Is C<LATIN CAPITAL LETTER A WITH ACUTE> equal to
+C<LATIN CAPITAL LETTER A>?)
+
+The short answer is that by default Perl compares equivalence (C<eq>,
+C<ne>) based only on code points of the characters. In the above
+case, the answer is no (because 0x00C1 != 0x0041). But sometimes, any
+CAPITAL LETTER As should be considered equal, or even As of any case.
+
+The long answer is that you need to consider character normalization
+and casing issues: see L<Unicode::Normalize>, Unicode Technical Report #15,
+L<Unicode Normalization Forms|http://www.unicode.org/unicode/reports/tr15> and
+sections on case mapping in the L<Unicode Standard|http://www.unicode.org>.
+
+As of Perl 5.8.0, the "Full" case-folding of I<Case
+Mappings/SpecialCasing> is implemented, but bugs remain in C<qr//i> with them.
+
+=item *
+
+String Collation
+
+People like to see their strings nicely sorted--or as Unicode
+parlance goes, collated. But again, what do you mean by collate?
+
+(Does C<LATIN CAPITAL LETTER A WITH ACUTE> come before or after
+C<LATIN CAPITAL LETTER A WITH GRAVE>?)
+
+The short answer is that by default, Perl compares strings (C<lt>,
+C<le>, C<cmp>, C<ge>, C<gt>) based only on the code points of the
+characters. In the above case, the answer is "after", since
+C<0x00C1> > C<0x00C0>.
+
+The long answer is that "it depends", and a good answer cannot be
+given without knowing (at the very least) the language context.
+See L<Unicode::Collate>, and I<Unicode Collation Algorithm>
+L<http://www.unicode.org/unicode/reports/tr10/>
+
+=back
+
+=head2 Miscellaneous
+
+=over 4
+
+=item *
+
+Character Ranges and Classes
+
+Character ranges in regular expression bracketed character classes ( e.g.,
+C</[a-z]/>) and in the C<tr///> (also known as C<y///>) operator are not
+magically Unicode-aware. What this means is that C<[A-Za-z]> will not
+magically start to mean "all alphabetic letters" (not that it does mean that
+even for 8-bit characters; for those, if you are using locales (L<perllocale>),
+use C</[[:alpha:]]/>; and if not, use the 8-bit-aware property C<\p{alpha}>).
+
+All the properties that begin with C<\p> (and its inverse C<\P>) are actually
+character classes that are Unicode-aware. There are dozens of them, see
+L<perluniprops>.
+
+You can use Unicode code points as the end points of character ranges, and the
+range will include all Unicode code points that lie between those end points.
+
+=item *
+
+String-To-Number Conversions
+
+Unicode does define several other decimal--and numeric--characters
+besides the familiar 0 to 9, such as the Arabic and Indic digits.
+Perl does not support string-to-number conversion for digits other
+than ASCII 0 to 9 (and ASCII a to f for hexadecimal).
+
+=back
+
+=head2 Questions With Answers
+
+=over 4
+
+=item *
+
+Will My Old Scripts Break?
+
+Very probably not. Unless you are generating Unicode characters
+somehow, old behaviour should be preserved. About the only behaviour
+that has changed and which could start generating Unicode is the old
+behaviour of C<chr()> where supplying an argument more than 255
+produced a character modulo 255. C<chr(300)>, for example, was equal
+to C<chr(45)> or "-" (in ASCII), now it is LATIN CAPITAL LETTER I WITH
+BREVE.
+
+=item *
+
+How Do I Make My Scripts Work With Unicode?
+
+Very little work should be needed since nothing changes until you
+generate Unicode data. The most important thing is getting input as
+Unicode; for that, see the earlier I/O discussion.
+
+=item *
+
+How Do I Know Whether My String Is In Unicode?
+
+You shouldn't have to care. But you may, because currently the semantics of the
+characters whose ordinals are in the range 128 to 255 are different depending on
+whether the string they are contained within is in Unicode or not.
+(See L<perlunicode/When Unicode Does Not Happen>.)
+
+To determine if a string is in Unicode, use:
+
+ print utf8::is_utf8($string) ? 1 : 0, "\n";
+
+But note that this doesn't mean that any of the characters in the
+string are necessary UTF-8 encoded, or that any of the characters have
+code points greater than 0xFF (255) or even 0x80 (128), or that the
+string has any characters at all. All the C<is_utf8()> does is to
+return the value of the internal "utf8ness" flag attached to the
+C<$string>. If the flag is off, the bytes in the scalar are interpreted
+as a single byte encoding. If the flag is on, the bytes in the scalar
+are interpreted as the (variable-length, potentially multi-byte) UTF-8 encoded
+code points of the characters. Bytes added to a UTF-8 encoded string are
+automatically upgraded to UTF-8. If mixed non-UTF-8 and UTF-8 scalars
+are merged (double-quoted interpolation, explicit concatenation, and
+printf/sprintf parameter substitution), the result will be UTF-8 encoded
+as if copies of the byte strings were upgraded to UTF-8: for example,
+
+ $a = "ab\x80c";
+ $b = "\x{100}";
+ print "$a = $b\n";
+
+the output string will be UTF-8-encoded C<ab\x80c = \x{100}\n>, but
+C<$a> will stay byte-encoded.
+
+Sometimes you might really need to know the byte length of a string
+instead of the character length. For that use either the
+C<Encode::encode_utf8()> function or the C<bytes> pragma and
+the C<length()> function:
+
+ my $unicode = chr(0x100);
+ print length($unicode), "\n"; # will print 1
+ require Encode;
+ print length(Encode::encode_utf8($unicode)), "\n"; # will print 2
+ use bytes;
+ print length($unicode), "\n"; # will also print 2
+ # (the 0xC4 0x80 of the UTF-8)
+ no bytes;
+
+=item *
+
+How Do I Detect Data That's Not Valid In a Particular Encoding?
+
+Use the C<Encode> package to try converting it.
+For example,
+
+ use Encode 'decode_utf8';
+
+ if (eval { decode_utf8($string, Encode::FB_CROAK); 1 }) {
+ # $string is valid utf8
+ } else {
+ # $string is not valid utf8
+ }
+
+Or use C<unpack> to try decoding it:
+
+ use warnings;
+ @chars = unpack("C0U*", $string_of_bytes_that_I_think_is_utf8);
+
+If invalid, a C<Malformed UTF-8 character> warning is produced. The "C0" means
+"process the string character per character". Without that, the
+C<unpack("U*", ...)> would work in C<U0> mode (the default if the format
+string starts with C<U>) and it would return the bytes making up the UTF-8
+encoding of the target string, something that will always work.
+
+=item *
+
+How Do I Convert Binary Data Into a Particular Encoding, Or Vice Versa?
+
+This probably isn't as useful as you might think.
+Normally, you shouldn't need to.
+
+In one sense, what you are asking doesn't make much sense: encodings
+are for characters, and binary data are not "characters", so converting
+"data" into some encoding isn't meaningful unless you know in what
+character set and encoding the binary data is in, in which case it's
+not just binary data, now is it?
+
+If you have a raw sequence of bytes that you know should be
+interpreted via a particular encoding, you can use C<Encode>:
+
+ use Encode 'from_to';
+ from_to($data, "iso-8859-1", "utf-8"); # from latin-1 to utf-8
+
+The call to C<from_to()> changes the bytes in C<$data>, but nothing
+material about the nature of the string has changed as far as Perl is
+concerned. Both before and after the call, the string C<$data>
+contains just a bunch of 8-bit bytes. As far as Perl is concerned,
+the encoding of the string remains as "system-native 8-bit bytes".
+
+You might relate this to a fictional 'Translate' module:
+
+ use Translate;
+ my $phrase = "Yes";
+ Translate::from_to($phrase, 'english', 'deutsch');
+ ## phrase now contains "Ja"
+
+The contents of the string changes, but not the nature of the string.
+Perl doesn't know any more after the call than before that the
+contents of the string indicates the affirmative.
+
+Back to converting data. If you have (or want) data in your system's
+native 8-bit encoding (e.g. Latin-1, EBCDIC, etc.), you can use
+pack/unpack to convert to/from Unicode.
+
+ $native_string = pack("W*", unpack("U*", $Unicode_string));
+ $Unicode_string = pack("U*", unpack("W*", $native_string));
+
+If you have a sequence of bytes you B<know> is valid UTF-8,
+but Perl doesn't know it yet, you can make Perl a believer, too:
+
+ use Encode 'decode_utf8';
+ $Unicode = decode_utf8($bytes);
+
+or:
+
+ $Unicode = pack("U0a*", $bytes);
+
+You can find the bytes that make up a UTF-8 sequence with
+
+ @bytes = unpack("C*", $Unicode_string)
+
+and you can create well-formed Unicode with
+
+ $Unicode_string = pack("U*", 0xff, ...)
+
+=item *
+
+How Do I Display Unicode? How Do I Input Unicode?
+
+See L<http://www.alanwood.net/unicode/> and
+L<http://www.cl.cam.ac.uk/~mgk25/unicode.html>
+
+=item *
+
+How Does Unicode Work With Traditional Locales?
+
+In Perl, not very well. Avoid using locales through the C<locale>
+pragma. Use only one or the other. But see L<perlrun> for the
+description of the C<-C> switch and its environment counterpart,
+C<$ENV{PERL_UNICODE}> to see how to enable various Unicode features,
+for example by using locale settings.
+
+=back
+
+=head2 Hexadecimal Notation
+
+The Unicode standard prefers using hexadecimal notation because
+that more clearly shows the division of Unicode into blocks of 256 characters.
+Hexadecimal is also simply shorter than decimal. You can use decimal
+notation, too, but learning to use hexadecimal just makes life easier
+with the Unicode standard. The C<U+HHHH> notation uses hexadecimal,
+for example.
+
+The C<0x> prefix means a hexadecimal number, the digits are 0-9 I<and>
+a-f (or A-F, case doesn't matter). Each hexadecimal digit represents
+four bits, or half a byte. C<print 0x..., "\n"> will show a
+hexadecimal number in decimal, and C<printf "%x\n", $decimal> will
+show a decimal number in hexadecimal. If you have just the
+"hex digits" of a hexadecimal number, you can use the C<hex()> function.
+
+ print 0x0009, "\n"; # 9
+ print 0x000a, "\n"; # 10
+ print 0x000f, "\n"; # 15
+ print 0x0010, "\n"; # 16
+ print 0x0011, "\n"; # 17
+ print 0x0100, "\n"; # 256
+
+ print 0x0041, "\n"; # 65
+
+ printf "%x\n", 65; # 41
+ printf "%#x\n", 65; # 0x41
+
+ print hex("41"), "\n"; # 65
+
+=head2 Further Resources
+
+=over 4
+
+=item *
+
+Unicode Consortium
+
+L<http://www.unicode.org/>
+
+=item *
+
+Unicode FAQ
+
+L<http://www.unicode.org/unicode/faq/>
+
+=item *
+
+Unicode Glossary
+
+L<http://www.unicode.org/glossary/>
+
+=item *
+
+Unicode Useful Resources
+
+L<http://www.unicode.org/unicode/onlinedat/resources.html>
+
+=item *
+
+Unicode and Multilingual Support in HTML, Fonts, Web Browsers and Other Applications
+
+L<http://www.alanwood.net/unicode/>
+
+=item *
+
+UTF-8 and Unicode FAQ for Unix/Linux
+
+L<http://www.cl.cam.ac.uk/~mgk25/unicode.html>
+
+=item *
+
+Legacy Character Sets
+
+L<http://www.czyborra.com/>
+L<http://www.eki.ee/letter/>
+
+=item *
+
+The Unicode support files live within the Perl installation in the
+directory
+
+ $Config{installprivlib}/unicore
+
+in Perl 5.8.0 or newer, and
+
+ $Config{installprivlib}/unicode
+
+in the Perl 5.6 series. (The renaming to F<lib/unicore> was done to
+avoid naming conflicts with lib/Unicode in case-insensitive filesystems.)
+The main Unicode data file is F<UnicodeData.txt> (or F<Unicode.301> in
+Perl 5.6.1.) You can find the C<$Config{installprivlib}> by
+
+ perl "-V:installprivlib"
+
+You can explore various information from the Unicode data files using
+the C<Unicode::UCD> module.
+
+=back
+
+=head1 UNICODE IN OLDER PERLS
+
+If you cannot upgrade your Perl to 5.8.0 or later, you can still
+do some Unicode processing by using the modules C<Unicode::String>,
+C<Unicode::Map8>, and C<Unicode::Map>, available from CPAN.
+If you have the GNU recode installed, you can also use the
+Perl front-end C<Convert::Recode> for character conversions.
+
+The following are fast conversions from ISO 8859-1 (Latin-1) bytes
+to UTF-8 bytes and back, the code works even with older Perl 5 versions.
+
+ # ISO 8859-1 to UTF-8
+ s/([\x80-\xFF])/chr(0xC0|ord($1)>>6).chr(0x80|ord($1)&0x3F)/eg;
+
+ # UTF-8 to ISO 8859-1
+ s/([\xC2\xC3])([\x80-\xBF])/chr(ord($1)<<6&0xC0|ord($2)&0x3F)/eg;
+
+=head1 SEE ALSO
+
+L<perlunitut>, L<perlunicode>, L<Encode>, L<open>, L<utf8>, L<bytes>,
+L<perlretut>, L<perlrun>, L<Unicode::Collate>, L<Unicode::Normalize>,
+L<Unicode::UCD>
+
+=head1 ACKNOWLEDGMENTS
+
+Thanks to the kind readers of the perl5-porters@perl.org,
+perl-unicode@perl.org, linux-utf8@nl.linux.org, and unicore@unicode.org
+mailing lists for their valuable feedback.
+
+=head1 AUTHOR, COPYRIGHT, AND LICENSE
+
+Copyright 2001-2002 Jarkko Hietaniemi E<lt>jhi@iki.fiE<gt>
+
+This document may be distributed under the same terms as Perl itself.
diff --git a/Master/tlpkg/tlperl/lib/pods/perluniprops.pod b/Master/tlpkg/tlperl/lib/pods/perluniprops.pod
new file mode 100644
index 00000000000..4768df20325
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perluniprops.pod
@@ -0,0 +1,3051 @@
+=begin comment
+
+# !!!!!!! DO NOT EDIT THIS FILE !!!!!!!
+# This file is machine-generated by mktables from the Unicode
+# database, Version 5.2.0. Any changes made here will be lost!
+
+
+To change this file, edit mktables instead.
+
+=end comment
+
+=head1 NAME
+
+perluniprops - Index of Unicode Version 5.2.0 properties in Perl
+
+=head1 DESCRIPTION
+
+There are many properties in Unicode, and Perl provides access to almost all of
+them, as well as some additional extensions and short-cut synonyms.
+
+And just about all of the few that aren't accessible through the Perl
+core are accessible through the modules: Unicode::Normalize and
+Unicode::UCD, and for Unihan properties, via the CPAN module Unicode::Unihan.
+
+This document merely lists all available properties and does not attempt to
+explain what each property really means. There is a brief description of each
+Perl extension. There is some detail about Blocks, Scripts, General_Category,
+and Bidi_Class in L<perlunicode>, but to find out about the intricacies of the
+Unicode properties, refer to the Unicode standard. A good starting place is
+L<http://www.unicode.org/reports/tr44/>. More information on the Perl extensions is in
+L<perlrecharclass>.
+
+Note that you can define your own properties; see
+L<perlunicode/"User-Defined Character Properties">.
+
+=head1 Properties accessible through \p{} and \P{}
+
+The Perl regular expression \p{} and \P{} constructs give access to most of
+the Unicode character properties. The table below shows all these constructs,
+both single and compound forms.
+
+B<Compound forms> consist of two components, separated by an equals sign or a
+colon. The first component is the property name, and the second component is
+the particular value of the property to match against, for example,
+'\p{Script: Greek}' or '\p{Script=Greek}' both mean to match characters
+whose Script property is Greek.
+
+B<Single forms>, like '\p{Greek}', are mostly Perl-defined shortcuts for
+their equivalent compound forms. The table shows these equivalences. (In our
+example, '\p{Greek}' is a just a shortcut for '\p{Script=Greek}'.)
+There are also a few Perl-defined single forms that are not shortcuts for a
+compound form. One such is \p{Word}. These are also listed in the table.
+
+In parsing these constructs, Perl always ignores Upper/lower case differences
+everywhere within the {braces}. Thus '\p{Greek}' means the same thing as
+'\p{greek}'. But note that changing the case of the 'p' or 'P' before the
+left brace completely changes the meaning of the construct, from "match" (for
+'\p{}') to "doesn't match" (for '\P{}'). Casing in this document is for
+improved legibility.
+
+Also, white space, hyphens, and underscores are also normally ignored
+everywhere between the {braces}, and hence can be freely added or removed
+even if the C</x> modifier hasn't been specified on the regular expression.
+But a 'B<T>' at the beginning of an entry in the table below
+means that tighter (stricter) rules are used for that entry:
+
+=over 4
+
+=item Single form (\p{name}) tighter rules:
+
+White space, hyphens, and underscores ARE significant
+except for:
+
+=over 4
+
+=item * white space adjacent to a non-word character
+
+=item * underscores separating digits in numbers
+
+=back
+
+That means, for example, that you can freely add or remove white space
+adjacent to (but within) the braces without affecting the meaning.
+
+=item Compound form (\p{name=value} or \p{name:value}) tighter rules:
+
+The tighter rules given above for the single form apply to everything to the
+right of the colon or equals; the looser rules still apply to everything to
+the left.
+
+That means, for example, that you can freely add or remove white space
+adjacent to (but within) the braces and the colon or equal sign.
+
+=back
+
+Some properties are considered obsolete, but still available. There are
+several varieties of obsolesence:
+
+=over 4
+
+=item Obsolete
+
+Properties marked with an 'B<O>' in the table are considered
+obsolete. At the time of this writing (Unicode version 5.2) there is no
+information in the Unicode standard about the implications of a property being
+obsolete.
+
+=item Stabilized
+
+Obsolete properties may be stabilized. This means that they are not actively
+maintained by Unicode, and will not be extended as new characters are added to
+the standard. Such properties are marked with an 'B<S>' in the
+table. At the time of this writing (Unicode version 5.2) there is no further
+information in the Unicode standard about the implications of a property being
+stabilized.
+
+=item Deprecated
+
+Obsolete properties may be deprecated. This means that their use is strongly
+discouraged, so much so that a warning will be issued if used, unless the
+regular expression is in the scope of a C<S<no warnings 'deprecated'>>
+statement. A 'B<D>' flags each such entry in the table, and
+the entry there for the longest, most descriptive version of the property will
+give the reason it is deprecated, and perhaps advice. Perl may issue such a
+warning, even for properties that aren't officially deprecated by Unicode,
+when there used to be characters or code points that were matched by them, but
+no longer. This is to warn you that your program may not work like it did on
+earlier Unicode releases.
+
+A deprecated property may be made unavailable in a future Perl version, so it
+is best to move away from them.
+
+=back
+
+Some Perl extensions are present for backwards compatibility and are
+discouraged from being used, but not obsolete. An 'B<X>'
+flags each such entry in the table.
+
+
+Matches in the Block property have shortcuts that begin with 'In_'. For
+example, \p{Block=Latin1} can be written as \p{In_Latin1}. For backward
+compatibility, if there is no conflict with another shortcut, these may also
+be written as \p{Latin1} or \p{Is_Latin1}. But, N.B., there are numerous
+such conflicting shortcuts. Use of these forms for Block is discouraged, and
+are flagged as such, not only because of the potential confusion as to what is
+meant, but also because a later release of Unicode may preempt the shortcut,
+and your program would no longer be correct. Use the 'In_' form instead to
+avoid this, or even more clearly, use the compound form, e.g.,
+\p{blk:latin1}. See L<perlunicode/"Blocks"> for more information about this.
+
+
+The table below has two columns. The left column contains the \p{}
+constructs to look up, possibly preceeded by the flags mentioned above; and
+the right column contains information about them, like a description, or
+synonyms. It shows both the single and compound forms for each property that
+has them. If the left column is a short name for a property, the right column
+will give its longer, more descriptive name; and if the left column is the
+longest name, the right column will show any equivalent shortest name, in both
+single and compound forms if applicable.
+
+The right column will also caution you if a property means something different
+than what might normally be expected.
+
+All single forms are Perl extensions; a few compound forms are as well, and
+are noted as such.
+
+Numbers in (parentheses) indicate the total number of code points matched by
+the property. For emphasis, those properties that match no code points at all
+are listed as well in a separate section following the table.
+
+There is no description given for most non-Perl defined properties (See
+http://www.unicode.org/reports/tr44/ for that).
+
+For compactness, 'B<*>' is used as a wildcard instead of showing all possible
+combinations. For example, entries like:
+
+ \p{Gc: *} \p{General_Category: *}
+
+mean that 'Gc' is a synonym for 'General_Category', and anything that is valid
+for the latter is also valid for the former. Similarly,
+
+ \p{Is_*} \p{*}
+
+means that if and only if, for example, \p{Foo} exists, then \p{Is_Foo} and
+\p{IsFoo} are also valid and all mean the same thing. And similarly,
+\p{Foo=Bar} means the same as \p{Is_Foo=Bar} and \p{IsFoo=Bar}. '*' here
+is restricted to something not beginning with an underscore.
+
+Also, in binary properties, 'Yes', 'T', and 'True' are all synonyms for 'Y'.
+And 'No', 'F', and 'False' are all synonyms for 'N'. The table shows 'Y*' and
+'N*' to indicate this, and doesn't have separate entries for the other
+possibilities. Note that not all properties which have values 'Yes' and 'No'
+are binary, and they have all their values spelled out without using this wild
+card, and a C<NOT> clause in their description that highlights their not being
+binary. These also require the compound form to match them, whereas true
+binary properties have both single and compound forms available.
+
+Note that all non-essential underscores are removed in the display of the
+short names below.
+
+B<Summary legend:>
+
+=over 4
+
+=item B<*> is a wild-card
+
+=item B<(\d+)> in the info column gives the number of code points matched by
+this property.
+
+=item B<D> means this is deprecated.
+
+=item B<O> means this is obsolete.
+
+=item B<S> means this is stabilized.
+
+=item B<T> means tighter (stricter) name matching applies.
+
+=item B<X> means use of this form is discouraged.
+
+=back
+
+ NAME INFO
+
+ X \p{Aegean_Numbers} \p{Block=Aegean_Numbers} (64)
+ T \p{Age: 1.1} Code point's usage introduced in version
+ 1.1 (33_979)
+ T \p{Age: 2.0} Code point's usage was introduced in
+ version 2.0; See also Property
+ 'Present_In' (144_521)
+ T \p{Age: 2.1} Code point's usage was introduced in
+ version 2.1; See also Property
+ 'Present_In' (2)
+ T \p{Age: 3.0} Code point's usage was introduced in
+ version 3.0; See also Property
+ 'Present_In' (10_307)
+ T \p{Age: 3.1} Code point's usage was introduced in
+ version 3.1; See also Property
+ 'Present_In' (44_978)
+ T \p{Age: 3.2} Code point's usage was introduced in
+ version 3.2; See also Property
+ 'Present_In' (1016)
+ T \p{Age: 4.0} Code point's usage was introduced in
+ version 4.0; See also Property
+ 'Present_In' (1226)
+ T \p{Age: 4.1} Code point's usage was introduced in
+ version 4.1; See also Property
+ 'Present_In' (1273)
+ T \p{Age: 5.0} Code point's usage was introduced in
+ version 5.0; See also Property
+ 'Present_In' (1369)
+ T \p{Age: 5.1} Code point's usage was introduced in
+ version 5.1; See also Property
+ 'Present_In' (1624)
+ T \p{Age: 5.2} Code point's usage was introduced in
+ version 5.2; See also Property
+ 'Present_In' (6648)
+ \p{Age: Unassigned} Code point's usage has not been assigned
+ in any Unicode release thus far.
+ (867_169)
+ \p{AHex} \p{ASCII_Hex_Digit} (= \p{ASCII_Hex_Digit=
+ Y}) (22)
+ \p{AHex: *} \p{ASCII_Hex_Digit: *}
+ \p{All} \p{Any} (1_114_112)
+ \p{Alnum} Alphabetic and (Decimal) Numeric (100_931)
+ \p{Alpha} \p{Alphabetic=Y} (100_520)
+ \p{Alpha: *} \p{Alphabetic: *}
+ \p{Alphabetic} \p{Alpha} (= \p{Alphabetic=Y}) (100_520)
+ \p{Alphabetic: N*} (Short: \p{Alpha=N}, \P{Alpha}) (1_013_592)
+ \p{Alphabetic: Y*} (Short: \p{Alpha=Y}, \p{Alpha}) (100_520)
+ X \p{Alphabetic_Presentation_Forms} \p{Block=
+ Alphabetic_Presentation_Forms} (80)
+ X \p{Ancient_Greek_Musical_Notation} \p{Block=
+ Ancient_Greek_Musical_Notation} (80)
+ X \p{Ancient_Greek_Numbers} \p{Block=Ancient_Greek_Numbers} (80)
+ X \p{Ancient_Symbols} \p{Block=Ancient_Symbols} (64)
+ \p{Any} [\x{0000}-\x{10FFFF}] (1_114_112)
+ \p{Arab} \p{Arabic} (= \p{Script=Arabic}) (NOT
+ \p{Block=Arabic}) (1030)
+ \p{Arabic} \p{Script=Arabic} (Short: \p{Arab}; NOT
+ \p{Block=Arabic}) (1030)
+ X \p{Arabic_Presentation_Forms_A} \p{Block=
+ Arabic_Presentation_Forms_A} (688)
+ X \p{Arabic_Presentation_Forms_B} \p{Block=
+ Arabic_Presentation_Forms_B} (144)
+ X \p{Arabic_Supplement} \p{Block=Arabic_Supplement} (48)
+ \p{Armenian} \p{Script=Armenian} (Short: \p{Armn}; NOT
+ \p{Block=Armenian}) (90)
+ \p{Armi} \p{Imperial_Aramaic} (= \p{Script=
+ Imperial_Aramaic}) (NOT \p{Block=
+ Imperial_Aramaic}) (31)
+ \p{Armn} \p{Armenian} (= \p{Script=Armenian}) (NOT
+ \p{Block=Armenian}) (90)
+ X \p{Arrows} \p{Block=Arrows} (112)
+ \p{ASCII} \p{Block=Basic_Latin} [[:ASCII:]] (128)
+ \p{ASCII_Hex_Digit} \p{ASCII_Hex_Digit=Y} (Short: \p{AHex})
+ (22)
+ \p{ASCII_Hex_Digit: N*} (Short: \p{AHex=N}, \P{AHex}) (1_114_090)
+ \p{ASCII_Hex_Digit: Y*} (Short: \p{AHex=Y}, \p{AHex}) (22)
+ \p{Assigned} All assigned code points (246_877)
+ \p{Avestan} \p{Script=Avestan} (Short: \p{Avst}; NOT
+ \p{Block=Avestan}) (61)
+ \p{Avst} \p{Avestan} (= \p{Script=Avestan}) (NOT
+ \p{Block=Avestan}) (61)
+ \p{Bali} \p{Balinese} (= \p{Script=Balinese}) (NOT
+ \p{Block=Balinese}) (121)
+ \p{Balinese} \p{Script=Balinese} (Short: \p{Bali}; NOT
+ \p{Block=Balinese}) (121)
+ \p{Bamu} \p{Bamum} (= \p{Script=Bamum}) (NOT
+ \p{Block=Bamum}) (88)
+ \p{Bamum} \p{Script=Bamum} (Short: \p{Bamu}; NOT
+ \p{Block=Bamum}) (88)
+ X \p{Basic_Latin} \p{ASCII} (= \p{Block=Basic_Latin}) (128)
+ \p{Bc: *} \p{Bidi_Class: *}
+ \p{Beng} \p{Bengali} (= \p{Script=Bengali}) (NOT
+ \p{Block=Bengali}) (92)
+ \p{Bengali} \p{Script=Bengali} (Short: \p{Beng}; NOT
+ \p{Block=Bengali}) (92)
+ \p{Bidi_C} \p{Bidi_Control} (= \p{Bidi_Control=Y}) (7)
+ \p{Bidi_C: *} \p{Bidi_Control: *}
+ \p{Bidi_Class: AL} \p{Bidi_Class=Arabic_Letter} (1116)
+ \p{Bidi_Class: AN} \p{Bidi_Class=Arabic_Number} (48)
+ \p{Bidi_Class: Arabic_Letter} (Short: \p{Bc=AL}) (1116)
+ \p{Bidi_Class: Arabic_Number} (Short: \p{Bc=AN}) (48)
+ \p{Bidi_Class: B} \p{Bidi_Class=Paragraph_Separator} (7)
+ \p{Bidi_Class: BN} \p{Bidi_Class=Boundary_Neutral} (4016)
+ \p{Bidi_Class: Boundary_Neutral} (Short: \p{Bc=BN}) (4016)
+ \p{Bidi_Class: Common_Separator} (Short: \p{Bc=CS}) (15)
+ \p{Bidi_Class: CS} \p{Bidi_Class=Common_Separator} (15)
+ \p{Bidi_Class: EN} \p{Bidi_Class=European_Number} (131)
+ \p{Bidi_Class: ES} \p{Bidi_Class=European_Separator} (12)
+ \p{Bidi_Class: ET} \p{Bidi_Class=European_Terminator} (63)
+ \p{Bidi_Class: European_Number} (Short: \p{Bc=EN}) (131)
+ \p{Bidi_Class: European_Separator} (Short: \p{Bc=ES}) (12)
+ \p{Bidi_Class: European_Terminator} (Short: \p{Bc=ET}) (63)
+ \p{Bidi_Class: L} \p{Bidi_Class=Left_To_Right} (1_099_541)
+ \p{Bidi_Class: Left_To_Right} (Short: \p{Bc=L}) (1_099_541)
+ \p{Bidi_Class: Left_To_Right_Embedding} (Short: \p{Bc=LRE}) (1)
+ \p{Bidi_Class: Left_To_Right_Override} (Short: \p{Bc=LRO}) (1)
+ \p{Bidi_Class: LRE} \p{Bidi_Class=Left_To_Right_Embedding} (1)
+ \p{Bidi_Class: LRO} \p{Bidi_Class=Left_To_Right_Override} (1)
+ \p{Bidi_Class: Nonspacing_Mark} (Short: \p{Bc=NSM}) (1173)
+ \p{Bidi_Class: NSM} \p{Bidi_Class=Nonspacing_Mark} (1173)
+ \p{Bidi_Class: ON} \p{Bidi_Class=Other_Neutral} (3523)
+ \p{Bidi_Class: Other_Neutral} (Short: \p{Bc=ON}) (3523)
+ \p{Bidi_Class: Paragraph_Separator} (Short: \p{Bc=B}) (7)
+ \p{Bidi_Class: PDF} \p{Bidi_Class=Pop_Directional_Format} (1)
+ \p{Bidi_Class: Pop_Directional_Format} (Short: \p{Bc=PDF}) (1)
+ \p{Bidi_Class: R} \p{Bidi_Class=Right_To_Left} (4441)
+ \p{Bidi_Class: Right_To_Left} (Short: \p{Bc=R}) (4441)
+ \p{Bidi_Class: Right_To_Left_Embedding} (Short: \p{Bc=RLE}) (1)
+ \p{Bidi_Class: Right_To_Left_Override} (Short: \p{Bc=RLO}) (1)
+ \p{Bidi_Class: RLE} \p{Bidi_Class=Right_To_Left_Embedding} (1)
+ \p{Bidi_Class: RLO} \p{Bidi_Class=Right_To_Left_Override} (1)
+ \p{Bidi_Class: S} \p{Bidi_Class=Segment_Separator} (3)
+ \p{Bidi_Class: Segment_Separator} (Short: \p{Bc=S}) (3)
+ \p{Bidi_Class: White_Space} (Short: \p{Bc=WS}) (18)
+ \p{Bidi_Class: WS} \p{Bidi_Class=White_Space} (18)
+ \p{Bidi_Control} \p{Bidi_Control=Y} (Short: \p{BidiC}) (7)
+ \p{Bidi_Control: N*} (Short: \p{BidiC=N}, \P{BidiC}) (1_114_105)
+ \p{Bidi_Control: Y*} (Short: \p{BidiC=Y}, \p{BidiC}) (7)
+ \p{Bidi_M} \p{Bidi_Mirrored} (= \p{Bidi_Mirrored=Y})
+ (543)
+ \p{Bidi_M: *} \p{Bidi_Mirrored: *}
+ \p{Bidi_Mirrored} \p{Bidi_Mirrored=Y} (Short: \p{BidiM})
+ (543)
+ \p{Bidi_Mirrored: N*} (Short: \p{BidiM=N}, \P{BidiM}) (1_113_569)
+ \p{Bidi_Mirrored: Y*} (Short: \p{BidiM=Y}, \p{BidiM}) (543)
+ \p{Blank} \h, Horizontal white space (19)
+ \p{Blk: *} \p{Block: *}
+ \p{Block: Aegean_Numbers} (Single: \p{InAegeanNumbers}) (64)
+ \p{Block: Alphabetic_Presentation_Forms} (Single:
+ \p{InAlphabeticPresentationForms}) (80)
+ \p{Block: Ancient_Greek_Musical_Notation} (Single:
+ \p{InAncientGreekMusicalNotation}) (80)
+ \p{Block: Ancient_Greek_Numbers} (Single:
+ \p{InAncientGreekNumbers}) (80)
+ \p{Block: Ancient_Symbols} (Single: \p{InAncientSymbols}) (64)
+ \p{Block: Arabic} (Single: \p{InArabic}; NOT \p{Arabic} NOR
+ \p{Is_Arabic}) (256)
+ \p{Block: Arabic_Presentation_Forms_A} (Single:
+ \p{InArabicPresentationFormsA}) (688)
+ \p{Block: Arabic_Presentation_Forms_B} (Single:
+ \p{InArabicPresentationFormsB}) (144)
+ \p{Block: Arabic_Supplement} (Single: \p{InArabicSupplement}) (48)
+ \p{Block: Armenian} (Single: \p{InArmenian}; NOT \p{Armenian}
+ NOR \p{Is_Armenian}) (96)
+ \p{Block: Arrows} (Single: \p{InArrows}) (112)
+ \p{Block: ASCII} \p{Block=Basic_Latin} (128)
+ \p{Block: Avestan} (Single: \p{InAvestan}; NOT \p{Avestan}
+ NOR \p{Is_Avestan}) (64)
+ \p{Block: Balinese} (Single: \p{InBalinese}; NOT \p{Balinese}
+ NOR \p{Is_Balinese}) (128)
+ \p{Block: Bamum} (Single: \p{InBamum}; NOT \p{Bamum} NOR
+ \p{Is_Bamum}) (96)
+ \p{Block: Basic_Latin} (Short: \p{Blk=ASCII}, \p{ASCII}) (128)
+ \p{Block: Bengali} (Single: \p{InBengali}; NOT \p{Bengali}
+ NOR \p{Is_Bengali}) (128)
+ \p{Block: Block_Elements} (Single: \p{InBlockElements}) (32)
+ \p{Block: Bopomofo} (Single: \p{InBopomofo}; NOT \p{Bopomofo}
+ NOR \p{Is_Bopomofo}) (48)
+ \p{Block: Bopomofo_Extended} (Single: \p{InBopomofoExtended}) (32)
+ \p{Block: Box_Drawing} (Single: \p{InBoxDrawing}) (128)
+ \p{Block: Braille_Patterns} (Single: \p{InBraillePatterns}) (256)
+ \p{Block: Buginese} (Single: \p{InBuginese}; NOT \p{Buginese}
+ NOR \p{Is_Buginese}) (32)
+ \p{Block: Buhid} (Single: \p{InBuhid}; NOT \p{Buhid} NOR
+ \p{Is_Buhid}) (32)
+ \p{Block: Byzantine_Musical_Symbols} (Single:
+ \p{InByzantineMusicalSymbols}) (256)
+ \p{Block: Canadian_Syllabics} \p{Block=
+ Unified_Canadian_Aboriginal_Syllabics}
+ (640)
+ \p{Block: Carian} (Single: \p{InCarian}; NOT \p{Carian} NOR
+ \p{Is_Carian}) (64)
+ \p{Block: Cham} (Single: \p{InCham}; NOT \p{Cham} NOR
+ \p{Is_Cham}) (96)
+ \p{Block: Cherokee} (Single: \p{InCherokee}; NOT \p{Cherokee}
+ NOR \p{Is_Cherokee}) (96)
+ \p{Block: CJK_Compatibility} (Single: \p{InCJKCompatibility}) (256)
+ \p{Block: CJK_Compatibility_Forms} (Single:
+ \p{InCJKCompatibilityForms}) (32)
+ \p{Block: CJK_Compatibility_Ideographs} (Single:
+ \p{InCJKCompatibilityIdeographs}) (512)
+ \p{Block: CJK_Compatibility_Ideographs_Supplement} (Single:
+ \p{InCJKCompatibilityIdeographs-
+ Supplement}) (544)
+ \p{Block: CJK_Radicals_Supplement} (Single:
+ \p{InCJKRadicalsSupplement}) (128)
+ \p{Block: CJK_Strokes} (Single: \p{InCJKStrokes}) (48)
+ \p{Block: CJK_Symbols_And_Punctuation} (Single:
+ \p{InCJKSymbolsAndPunctuation}) (64)
+ \p{Block: CJK_Unified_Ideographs} (Single:
+ \p{InCJKUnifiedIdeographs}) (20_992)
+ \p{Block: CJK_Unified_Ideographs_Extension_A} (Single:
+ \p{InCJKUnifiedIdeographsExtensionA})
+ (6592)
+ \p{Block: CJK_Unified_Ideographs_Extension_B} (Single:
+ \p{InCJKUnifiedIdeographsExtensionB})
+ (42_720)
+ \p{Block: CJK_Unified_Ideographs_Extension_C} (Single:
+ \p{InCJKUnifiedIdeographsExtensionC})
+ (4160)
+ \p{Block: Combining_Diacritical_Marks} (Single:
+ \p{InCombiningDiacriticalMarks}) (112)
+ \p{Block: Combining_Diacritical_Marks_For_Symbols} (Short: \p{Blk=
+ CombiningMarksForSymbols},
+ \p{InCombiningMarksForSymbols}) (48)
+ \p{Block: Combining_Diacritical_Marks_Supplement} (Single:
+ \p{InCombiningDiacriticalMarks-
+ Supplement}) (64)
+ \p{Block: Combining_Half_Marks} (Single: \p{InCombiningHalfMarks})
+ (16)
+ \p{Block: Combining_Marks_For_Symbols} \p{Block=
+ Combining_Diacritical_Marks_For_Symbols}
+ (48)
+ \p{Block: Common_Indic_Number_Forms} (Single:
+ \p{InCommonIndicNumberForms}) (16)
+ \p{Block: Control_Pictures} (Single: \p{InControlPictures}) (64)
+ \p{Block: Coptic} (Single: \p{InCoptic}; NOT \p{Coptic} NOR
+ \p{Is_Coptic}) (128)
+ \p{Block: Counting_Rod_Numerals} (Single:
+ \p{InCountingRodNumerals}) (32)
+ \p{Block: Cuneiform} (Single: \p{InCuneiform}; NOT
+ \p{Cuneiform} NOR \p{Is_Cuneiform})
+ (1024)
+ \p{Block: Cuneiform_Numbers_And_Punctuation} (Single:
+ \p{InCuneiformNumbersAndPunctuation})
+ (128)
+ \p{Block: Currency_Symbols} (Single: \p{InCurrencySymbols}) (48)
+ \p{Block: Cypriot_Syllabary} (Single: \p{InCypriotSyllabary}) (64)
+ \p{Block: Cyrillic} (Single: \p{InCyrillic}; NOT \p{Cyrillic}
+ NOR \p{Is_Cyrillic}) (256)
+ \p{Block: Cyrillic_Extended_A} (Single: \p{InCyrillicExtendedA})
+ (32)
+ \p{Block: Cyrillic_Extended_B} (Single: \p{InCyrillicExtendedB})
+ (96)
+ \p{Block: Cyrillic_Supplement} (Single: \p{InCyrillicSupplement})
+ (48)
+ \p{Block: Cyrillic_Supplementary} \p{Block=Cyrillic_Supplement}
+ (48)
+ \p{Block: Deseret} (Single: \p{InDeseret}) (80)
+ \p{Block: Devanagari} (Single: \p{InDevanagari}; NOT
+ \p{Devanagari} NOR \p{Is_Devanagari})
+ (128)
+ \p{Block: Devanagari_Extended} (Single: \p{InDevanagariExtended})
+ (32)
+ \p{Block: Dingbats} (Single: \p{InDingbats}) (192)
+ \p{Block: Domino_Tiles} (Single: \p{InDominoTiles}) (112)
+ \p{Block: Egyptian_Hieroglyphs} (Single:
+ \p{InEgyptianHieroglyphs}; NOT
+ \p{Egyptian_Hieroglyphs} NOR
+ \p{Is_Egyptian_Hieroglyphs}) (1072)
+ \p{Block: Enclosed_Alphanumeric_Supplement} (Single:
+ \p{InEnclosedAlphanumericSupplement})
+ (256)
+ \p{Block: Enclosed_Alphanumerics} (Single:
+ \p{InEnclosedAlphanumerics}) (160)
+ \p{Block: Enclosed_CJK_Letters_And_Months} (Single:
+ \p{InEnclosedCJKLettersAndMonths}) (256)
+ \p{Block: Enclosed_Ideographic_Supplement} (Single:
+ \p{InEnclosedIdeographicSupplement})
+ (256)
+ \p{Block: Ethiopic} (Single: \p{InEthiopic}; NOT \p{Ethiopic}
+ NOR \p{Is_Ethiopic}) (384)
+ \p{Block: Ethiopic_Extended} (Single: \p{InEthiopicExtended}) (96)
+ \p{Block: Ethiopic_Supplement} (Single: \p{InEthiopicSupplement})
+ (32)
+ \p{Block: General_Punctuation} (Single: \p{InGeneralPunctuation})
+ (112)
+ \p{Block: Geometric_Shapes} (Single: \p{InGeometricShapes}) (96)
+ \p{Block: Georgian} (Single: \p{InGeorgian}; NOT \p{Georgian}
+ NOR \p{Is_Georgian}) (96)
+ \p{Block: Georgian_Supplement} (Single: \p{InGeorgianSupplement})
+ (48)
+ \p{Block: Glagolitic} (Single: \p{InGlagolitic}; NOT
+ \p{Glagolitic} NOR \p{Is_Glagolitic})
+ (96)
+ \p{Block: Gothic} (Single: \p{InGothic}; NOT \p{Gothic} NOR
+ \p{Is_Gothic}) (32)
+ \p{Block: Greek} \p{Block=Greek_And_Coptic} (NOT \p{Greek}
+ NOR \p{Is_Greek}) (144)
+ \p{Block: Greek_And_Coptic} (Short: \p{Blk=Greek}, \p{InGreek};
+ NOT \p{Greek} NOR \p{Is_Greek}) (144)
+ \p{Block: Greek_Extended} (Single: \p{InGreekExtended}) (256)
+ \p{Block: Gujarati} (Single: \p{InGujarati}; NOT \p{Gujarati}
+ NOR \p{Is_Gujarati}) (128)
+ \p{Block: Gurmukhi} (Single: \p{InGurmukhi}; NOT \p{Gurmukhi}
+ NOR \p{Is_Gurmukhi}) (128)
+ \p{Block: Halfwidth_And_Fullwidth_Forms} (Single:
+ \p{InHalfwidthAndFullwidthForms}) (240)
+ \p{Block: Hangul_Compatibility_Jamo} (Single:
+ \p{InHangulCompatibilityJamo}) (96)
+ \p{Block: Hangul_Jamo} (Single: \p{InHangulJamo}) (256)
+ \p{Block: Hangul_Jamo_Extended_A} (Single:
+ \p{InHangulJamoExtendedA}) (32)
+ \p{Block: Hangul_Jamo_Extended_B} (Single:
+ \p{InHangulJamoExtendedB}) (80)
+ \p{Block: Hangul_Syllables} (Single: \p{InHangulSyllables})
+ (11_184)
+ \p{Block: Hanunoo} (Single: \p{InHanunoo}; NOT \p{Hanunoo}
+ NOR \p{Is_Hanunoo}) (32)
+ \p{Block: Hebrew} (Single: \p{InHebrew}; NOT \p{Hebrew} NOR
+ \p{Is_Hebrew}) (112)
+ \p{Block: High_Private_Use_Surrogates} (Single:
+ \p{InHighPrivateUseSurrogates}) (128)
+ \p{Block: High_Surrogates} (Single: \p{InHighSurrogates}) (896)
+ \p{Block: Hiragana} (Single: \p{InHiragana}; NOT \p{Hiragana}
+ NOR \p{Is_Hiragana}) (96)
+ \p{Block: Ideographic_Description_Characters} (Single:
+ \p{InIdeographicDescriptionCharacters})
+ (16)
+ \p{Block: Imperial_Aramaic} (Single: \p{InImperialAramaic}; NOT
+ \p{Imperial_Aramaic} NOR
+ \p{Is_Imperial_Aramaic}) (32)
+ \p{Block: Inscriptional_Pahlavi} (Single:
+ \p{InInscriptionalPahlavi}; NOT
+ \p{Inscriptional_Pahlavi} NOR
+ \p{Is_Inscriptional_Pahlavi}) (32)
+ \p{Block: Inscriptional_Parthian} (Single:
+ \p{InInscriptionalParthian}; NOT
+ \p{Inscriptional_Parthian} NOR
+ \p{Is_Inscriptional_Parthian}) (32)
+ \p{Block: IPA_Extensions} (Single: \p{InIPAExtensions}) (96)
+ \p{Block: Javanese} (Single: \p{InJavanese}; NOT \p{Javanese}
+ NOR \p{Is_Javanese}) (96)
+ \p{Block: Kaithi} (Single: \p{InKaithi}; NOT \p{Kaithi} NOR
+ \p{Is_Kaithi}) (80)
+ \p{Block: Kanbun} (Single: \p{InKanbun}) (16)
+ \p{Block: Kangxi_Radicals} (Single: \p{InKangxiRadicals}) (224)
+ \p{Block: Kannada} (Single: \p{InKannada}; NOT \p{Kannada}
+ NOR \p{Is_Kannada}) (128)
+ \p{Block: Katakana} (Single: \p{InKatakana}; NOT \p{Katakana}
+ NOR \p{Is_Katakana}) (96)
+ \p{Block: Katakana_Phonetic_Extensions} (Single:
+ \p{InKatakanaPhoneticExtensions}) (16)
+ \p{Block: Kayah_Li} (Single: \p{InKayahLi}) (48)
+ \p{Block: Kharoshthi} (Single: \p{InKharoshthi}; NOT
+ \p{Kharoshthi} NOR \p{Is_Kharoshthi})
+ (96)
+ \p{Block: Khmer} (Single: \p{InKhmer}; NOT \p{Khmer} NOR
+ \p{Is_Khmer}) (128)
+ \p{Block: Khmer_Symbols} (Single: \p{InKhmerSymbols}) (32)
+ \p{Block: Lao} (Single: \p{InLao}; NOT \p{Lao} NOR
+ \p{Is_Lao}) (128)
+ \p{Block: Latin_1} \p{Block=Latin_1_Supplement} (128)
+ \p{Block: Latin_1_Supplement} (Short: \p{Blk=Latin1},
+ \p{InLatin1}) (128)
+ \p{Block: Latin_Extended_A} (Single: \p{InLatinExtendedA}) (128)
+ \p{Block: Latin_Extended_Additional} (Single:
+ \p{InLatinExtendedAdditional}) (256)
+ \p{Block: Latin_Extended_B} (Single: \p{InLatinExtendedB}) (208)
+ \p{Block: Latin_Extended_C} (Single: \p{InLatinExtendedC}) (32)
+ \p{Block: Latin_Extended_D} (Single: \p{InLatinExtendedD}) (224)
+ \p{Block: Lepcha} (Single: \p{InLepcha}; NOT \p{Lepcha} NOR
+ \p{Is_Lepcha}) (80)
+ \p{Block: Letterlike_Symbols} (Single: \p{InLetterlikeSymbols})
+ (80)
+ \p{Block: Limbu} (Single: \p{InLimbu}; NOT \p{Limbu} NOR
+ \p{Is_Limbu}) (80)
+ \p{Block: Linear_B_Ideograms} (Single: \p{InLinearBIdeograms})
+ (128)
+ \p{Block: Linear_B_Syllabary} (Single: \p{InLinearBSyllabary})
+ (128)
+ \p{Block: Lisu} (Single: \p{InLisu}) (48)
+ \p{Block: Low_Surrogates} (Single: \p{InLowSurrogates}) (1024)
+ \p{Block: Lycian} (Single: \p{InLycian}; NOT \p{Lycian} NOR
+ \p{Is_Lycian}) (32)
+ \p{Block: Lydian} (Single: \p{InLydian}; NOT \p{Lydian} NOR
+ \p{Is_Lydian}) (32)
+ \p{Block: Mahjong_Tiles} (Single: \p{InMahjongTiles}) (48)
+ \p{Block: Malayalam} (Single: \p{InMalayalam}; NOT
+ \p{Malayalam} NOR \p{Is_Malayalam}) (128)
+ \p{Block: Mathematical_Alphanumeric_Symbols} (Single:
+ \p{InMathematicalAlphanumericSymbols})
+ (1024)
+ \p{Block: Mathematical_Operators} (Single:
+ \p{InMathematicalOperators}) (256)
+ \p{Block: Meetei_Mayek} (Single: \p{InMeeteiMayek}; NOT
+ \p{Meetei_Mayek} NOR
+ \p{Is_Meetei_Mayek}) (64)
+ \p{Block: Miscellaneous_Mathematical_Symbols_A} (Single:
+ \p{InMiscellaneousMathematicalSymbolsA})
+ (48)
+ \p{Block: Miscellaneous_Mathematical_Symbols_B} (Single:
+ \p{InMiscellaneousMathematicalSymbolsB})
+ (128)
+ \p{Block: Miscellaneous_Symbols} (Single:
+ \p{InMiscellaneousSymbols}) (256)
+ \p{Block: Miscellaneous_Symbols_And_Arrows} (Single:
+ \p{InMiscellaneousSymbolsAndArrows})
+ (256)
+ \p{Block: Miscellaneous_Technical} (Single:
+ \p{InMiscellaneousTechnical}) (256)
+ \p{Block: Modifier_Tone_Letters} (Single:
+ \p{InModifierToneLetters}) (32)
+ \p{Block: Mongolian} (Single: \p{InMongolian}; NOT
+ \p{Mongolian} NOR \p{Is_Mongolian}) (176)
+ \p{Block: Musical_Symbols} (Single: \p{InMusicalSymbols}) (256)
+ \p{Block: Myanmar} (Single: \p{InMyanmar}; NOT \p{Myanmar}
+ NOR \p{Is_Myanmar}) (160)
+ \p{Block: Myanmar_Extended_A} (Single: \p{InMyanmarExtendedA}) (32)
+ \p{Block: New_Tai_Lue} (Single: \p{InNewTaiLue}; NOT
+ \p{New_Tai_Lue} NOR \p{Is_New_Tai_Lue})
+ (96)
+ \p{Block: NKo} (Single: \p{InNKo}; NOT \p{Nko} NOR
+ \p{Is_NKo}) (64)
+ \p{Block: No_Block} (Single: \p{InNoBlock}) (864_192)
+ \p{Block: Number_Forms} (Single: \p{InNumberForms}) (64)
+ \p{Block: Ogham} (Single: \p{InOgham}; NOT \p{Ogham} NOR
+ \p{Is_Ogham}) (32)
+ \p{Block: Ol_Chiki} (Single: \p{InOlChiki}) (48)
+ \p{Block: Old_Italic} (Single: \p{InOldItalic}; NOT
+ \p{Old_Italic} NOR \p{Is_Old_Italic})
+ (48)
+ \p{Block: Old_Persian} (Single: \p{InOldPersian}; NOT
+ \p{Old_Persian} NOR \p{Is_Old_Persian})
+ (64)
+ \p{Block: Old_South_Arabian} (Single: \p{InOldSouthArabian}) (32)
+ \p{Block: Old_Turkic} (Single: \p{InOldTurkic}; NOT
+ \p{Old_Turkic} NOR \p{Is_Old_Turkic})
+ (80)
+ \p{Block: Optical_Character_Recognition} (Single:
+ \p{InOpticalCharacterRecognition}) (32)
+ \p{Block: Oriya} (Single: \p{InOriya}; NOT \p{Oriya} NOR
+ \p{Is_Oriya}) (128)
+ \p{Block: Osmanya} (Single: \p{InOsmanya}; NOT \p{Osmanya}
+ NOR \p{Is_Osmanya}) (48)
+ \p{Block: Phags_Pa} (Single: \p{InPhagsPa}; NOT \p{Phags_Pa}
+ NOR \p{Is_Phags_Pa}) (64)
+ \p{Block: Phaistos_Disc} (Single: \p{InPhaistosDisc}) (48)
+ \p{Block: Phoenician} (Single: \p{InPhoenician}; NOT
+ \p{Phoenician} NOR \p{Is_Phoenician})
+ (32)
+ \p{Block: Phonetic_Extensions} (Single: \p{InPhoneticExtensions})
+ (128)
+ \p{Block: Phonetic_Extensions_Supplement} (Single:
+ \p{InPhoneticExtensionsSupplement}) (64)
+ \p{Block: Private_Use} \p{Block=Private_Use_Area} (NOT
+ \p{Private_Use} NOR \p{Is_Private_Use})
+ (6400)
+ \p{Block: Private_Use_Area} (Short: \p{Blk=PrivateUse},
+ \p{InPrivateUse}; NOT \p{Private_Use}
+ NOR \p{Is_Private_Use}) (6400)
+ \p{Block: Rejang} (Single: \p{InRejang}; NOT \p{Rejang} NOR
+ \p{Is_Rejang}) (48)
+ \p{Block: Rumi_Numeral_Symbols} (Single: \p{InRumiNumeralSymbols})
+ (32)
+ \p{Block: Runic} (Single: \p{InRunic}; NOT \p{Runic} NOR
+ \p{Is_Runic}) (96)
+ \p{Block: Samaritan} (Single: \p{InSamaritan}; NOT
+ \p{Samaritan} NOR \p{Is_Samaritan}) (64)
+ \p{Block: Saurashtra} (Single: \p{InSaurashtra}; NOT
+ \p{Saurashtra} NOR \p{Is_Saurashtra})
+ (96)
+ \p{Block: Shavian} (Single: \p{InShavian}) (48)
+ \p{Block: Sinhala} (Single: \p{InSinhala}; NOT \p{Sinhala}
+ NOR \p{Is_Sinhala}) (128)
+ \p{Block: Small_Form_Variants} (Single: \p{InSmallFormVariants})
+ (32)
+ \p{Block: Spacing_Modifier_Letters} (Single:
+ \p{InSpacingModifierLetters}) (80)
+ \p{Block: Specials} (Single: \p{InSpecials}) (16)
+ \p{Block: Sundanese} (Single: \p{InSundanese}; NOT
+ \p{Sundanese} NOR \p{Is_Sundanese}) (64)
+ \p{Block: Superscripts_And_Subscripts} (Single:
+ \p{InSuperscriptsAndSubscripts}) (48)
+ \p{Block: Supplemental_Arrows_A} (Single:
+ \p{InSupplementalArrowsA}) (16)
+ \p{Block: Supplemental_Arrows_B} (Single:
+ \p{InSupplementalArrowsB}) (128)
+ \p{Block: Supplemental_Mathematical_Operators} (Single:
+ \p{InSupplementalMathematicalOperators})
+ (256)
+ \p{Block: Supplemental_Punctuation} (Single:
+ \p{InSupplementalPunctuation}) (128)
+ \p{Block: Supplementary_Private_Use_Area_A} (Single:
+ \p{InSupplementaryPrivateUseAreaA})
+ (65_536)
+ \p{Block: Supplementary_Private_Use_Area_B} (Single:
+ \p{InSupplementaryPrivateUseAreaB})
+ (65_536)
+ \p{Block: Syloti_Nagri} (Single: \p{InSylotiNagri}; NOT
+ \p{Syloti_Nagri} NOR
+ \p{Is_Syloti_Nagri}) (48)
+ \p{Block: Syriac} (Single: \p{InSyriac}; NOT \p{Syriac} NOR
+ \p{Is_Syriac}) (80)
+ \p{Block: Tagalog} (Single: \p{InTagalog}; NOT \p{Tagalog}
+ NOR \p{Is_Tagalog}) (32)
+ \p{Block: Tagbanwa} (Single: \p{InTagbanwa}; NOT \p{Tagbanwa}
+ NOR \p{Is_Tagbanwa}) (32)
+ \p{Block: Tags} (Single: \p{InTags}) (128)
+ \p{Block: Tai_Le} (Single: \p{InTaiLe}; NOT \p{Tai_Le} NOR
+ \p{Is_Tai_Le}) (48)
+ \p{Block: Tai_Tham} (Single: \p{InTaiTham}; NOT \p{Tai_Tham}
+ NOR \p{Is_Tai_Tham}) (144)
+ \p{Block: Tai_Viet} (Single: \p{InTaiViet}; NOT \p{Tai_Viet}
+ NOR \p{Is_Tai_Viet}) (96)
+ \p{Block: Tai_Xuan_Jing_Symbols} (Single:
+ \p{InTaiXuanJingSymbols}) (96)
+ \p{Block: Tamil} (Single: \p{InTamil}; NOT \p{Tamil} NOR
+ \p{Is_Tamil}) (128)
+ \p{Block: Telugu} (Single: \p{InTelugu}; NOT \p{Telugu} NOR
+ \p{Is_Telugu}) (128)
+ \p{Block: Thaana} (Single: \p{InThaana}; NOT \p{Thaana} NOR
+ \p{Is_Thaana}) (64)
+ \p{Block: Thai} (Single: \p{InThai}; NOT \p{Thai} NOR
+ \p{Is_Thai}) (128)
+ \p{Block: Tibetan} (Single: \p{InTibetan}; NOT \p{Tibetan}
+ NOR \p{Is_Tibetan}) (256)
+ \p{Block: Tifinagh} (Single: \p{InTifinagh}; NOT \p{Tifinagh}
+ NOR \p{Is_Tifinagh}) (80)
+ \p{Block: Ugaritic} (Single: \p{InUgaritic}; NOT \p{Ugaritic}
+ NOR \p{Is_Ugaritic}) (32)
+ \p{Block: Unified_Canadian_Aboriginal_Syllabics} (Short: \p{Blk=
+ CanadianSyllabics},
+ \p{InCanadianSyllabics}) (640)
+ \p{Block: Unified_Canadian_Aboriginal_Syllabics_Extended} (Single:
+ \p{InUnifiedCanadianAboriginalSyllabics-
+ Extended}) (80)
+ \p{Block: Vai} (Single: \p{InVai}; NOT \p{Vai} NOR
+ \p{Is_Vai}) (320)
+ \p{Block: Variation_Selectors} (Single: \p{InVariationSelectors})
+ (16)
+ \p{Block: Variation_Selectors_Supplement} (Single:
+ \p{InVariationSelectorsSupplement}) (240)
+ \p{Block: Vedic_Extensions} (Single: \p{InVedicExtensions}) (48)
+ \p{Block: Vertical_Forms} (Single: \p{InVerticalForms}) (16)
+ \p{Block: Yi_Radicals} (Single: \p{InYiRadicals}) (64)
+ \p{Block: Yi_Syllables} (Single: \p{InYiSyllables}) (1168)
+ \p{Block: Yijing_Hexagram_Symbols} (Single:
+ \p{InYijingHexagramSymbols}) (64)
+ X \p{Block_Elements} \p{Block=Block_Elements} (32)
+ \p{Bopo} \p{Bopomofo} (= \p{Script=Bopomofo}) (NOT
+ \p{Block=Bopomofo}) (65)
+ \p{Bopomofo} \p{Script=Bopomofo} (Short: \p{Bopo}; NOT
+ \p{Block=Bopomofo}) (65)
+ X \p{Bopomofo_Extended} \p{Block=Bopomofo_Extended} (32)
+ X \p{Box_Drawing} \p{Block=Box_Drawing} (128)
+ \p{Brai} \p{Braille} (= \p{Script=Braille}) (256)
+ \p{Braille} \p{Script=Braille} (Short: \p{Brai}) (256)
+ X \p{Braille_Patterns} \p{Block=Braille_Patterns} (256)
+ \p{Bugi} \p{Buginese} (= \p{Script=Buginese}) (NOT
+ \p{Block=Buginese}) (30)
+ \p{Buginese} \p{Script=Buginese} (Short: \p{Bugi}; NOT
+ \p{Block=Buginese}) (30)
+ \p{Buhd} \p{Buhid} (= \p{Script=Buhid}) (NOT
+ \p{Block=Buhid}) (20)
+ \p{Buhid} \p{Script=Buhid} (Short: \p{Buhd}; NOT
+ \p{Block=Buhid}) (20)
+ X \p{Byzantine_Musical_Symbols} \p{Block=Byzantine_Musical_Symbols}
+ (256)
+ \p{C} \p{Other} (= \p{General_Category=Other})
+ (1_006_956)
+ \p{Canadian_Aboriginal} \p{Script=Canadian_Aboriginal} (Short:
+ \p{Cans}) (710)
+ X \p{Canadian_Syllabics} \p{Unified_Canadian_Aboriginal_Syllabics}
+ (= \p{Block=
+ Unified_Canadian_Aboriginal_Syllabics})
+ (640)
+ T \p{Canonical_Combining_Class: 0} \p{Canonical_Combining_Class=
+ Not_Reordered} (1_113_518)
+ T \p{Canonical_Combining_Class: 1} \p{Canonical_Combining_Class=
+ Overlay} (26)
+ T \p{Canonical_Combining_Class: 7} \p{Canonical_Combining_Class=
+ Nukta} (11)
+ T \p{Canonical_Combining_Class: 8} \p{Canonical_Combining_Class=
+ Kana_Voicing} (2)
+ T \p{Canonical_Combining_Class: 9} \p{Canonical_Combining_Class=
+ Virama} (27)
+ T \p{Canonical_Combining_Class: 10} (Short: \p{Ccc=10}) (1)
+ T \p{Canonical_Combining_Class: 11} (Short: \p{Ccc=11}) (1)
+ T \p{Canonical_Combining_Class: 12} (Short: \p{Ccc=12}) (1)
+ T \p{Canonical_Combining_Class: 13} (Short: \p{Ccc=13}) (1)
+ T \p{Canonical_Combining_Class: 14} (Short: \p{Ccc=14}) (1)
+ T \p{Canonical_Combining_Class: 15} (Short: \p{Ccc=15}) (1)
+ T \p{Canonical_Combining_Class: 16} (Short: \p{Ccc=16}) (1)
+ T \p{Canonical_Combining_Class: 17} (Short: \p{Ccc=17}) (1)
+ T \p{Canonical_Combining_Class: 18} (Short: \p{Ccc=18}) (2)
+ T \p{Canonical_Combining_Class: 19} (Short: \p{Ccc=19}) (2)
+ T \p{Canonical_Combining_Class: 20} (Short: \p{Ccc=20}) (1)
+ T \p{Canonical_Combining_Class: 21} (Short: \p{Ccc=21}) (1)
+ T \p{Canonical_Combining_Class: 22} (Short: \p{Ccc=22}) (1)
+ T \p{Canonical_Combining_Class: 23} (Short: \p{Ccc=23}) (1)
+ T \p{Canonical_Combining_Class: 24} (Short: \p{Ccc=24}) (1)
+ T \p{Canonical_Combining_Class: 25} (Short: \p{Ccc=25}) (1)
+ T \p{Canonical_Combining_Class: 26} (Short: \p{Ccc=26}) (1)
+ T \p{Canonical_Combining_Class: 27} (Short: \p{Ccc=27}) (1)
+ T \p{Canonical_Combining_Class: 28} (Short: \p{Ccc=28}) (1)
+ T \p{Canonical_Combining_Class: 29} (Short: \p{Ccc=29}) (1)
+ T \p{Canonical_Combining_Class: 30} (Short: \p{Ccc=30}) (2)
+ T \p{Canonical_Combining_Class: 31} (Short: \p{Ccc=31}) (2)
+ T \p{Canonical_Combining_Class: 32} (Short: \p{Ccc=32}) (2)
+ T \p{Canonical_Combining_Class: 33} (Short: \p{Ccc=33}) (1)
+ T \p{Canonical_Combining_Class: 34} (Short: \p{Ccc=34}) (1)
+ T \p{Canonical_Combining_Class: 35} (Short: \p{Ccc=35}) (1)
+ T \p{Canonical_Combining_Class: 36} (Short: \p{Ccc=36}) (1)
+ T \p{Canonical_Combining_Class: 84} (Short: \p{Ccc=84}) (1)
+ T \p{Canonical_Combining_Class: 91} (Short: \p{Ccc=91}) (1)
+ T \p{Canonical_Combining_Class: 103} (Short: \p{Ccc=103}) (2)
+ T \p{Canonical_Combining_Class: 107} (Short: \p{Ccc=107}) (4)
+ T \p{Canonical_Combining_Class: 118} (Short: \p{Ccc=118}) (2)
+ T \p{Canonical_Combining_Class: 122} (Short: \p{Ccc=122}) (4)
+ T \p{Canonical_Combining_Class: 129} (Short: \p{Ccc=129}) (1)
+ T \p{Canonical_Combining_Class: 130} (Short: \p{Ccc=130}) (6)
+ T \p{Canonical_Combining_Class: 132} (Short: \p{Ccc=132}) (1)
+ T \p{Canonical_Combining_Class: 200} \p{Canonical_Combining_Class=
+ Attached_Below_Left} (0)
+ T \p{Canonical_Combining_Class: 202} \p{Canonical_Combining_Class=
+ Attached_Below} (5)
+ T \p{Canonical_Combining_Class: 214} \p{Canonical_Combining_Class=
+ Attached_Above} (1)
+ T \p{Canonical_Combining_Class: 216} \p{Canonical_Combining_Class=
+ Attached_Above_Right} (9)
+ T \p{Canonical_Combining_Class: 218} \p{Canonical_Combining_Class=
+ Below_Left} (1)
+ T \p{Canonical_Combining_Class: 220} \p{Canonical_Combining_Class=
+ Below} (117)
+ T \p{Canonical_Combining_Class: 222} \p{Canonical_Combining_Class=
+ Below_Right} (4)
+ T \p{Canonical_Combining_Class: 224} \p{Canonical_Combining_Class=
+ Left} (2)
+ T \p{Canonical_Combining_Class: 226} \p{Canonical_Combining_Class=
+ Right} (1)
+ T \p{Canonical_Combining_Class: 228} \p{Canonical_Combining_Class=
+ Above_Left} (3)
+ T \p{Canonical_Combining_Class: 230} \p{Canonical_Combining_Class=
+ Above} (318)
+ T \p{Canonical_Combining_Class: 232} \p{Canonical_Combining_Class=
+ Above_Right} (4)
+ T \p{Canonical_Combining_Class: 233} \p{Canonical_Combining_Class=
+ Double_Below} (3)
+ T \p{Canonical_Combining_Class: 234} \p{Canonical_Combining_Class=
+ Double_Above} (5)
+ T \p{Canonical_Combining_Class: 240} \p{Canonical_Combining_Class=
+ Iota_Subscript} (1)
+ \p{Canonical_Combining_Class: A} \p{Canonical_Combining_Class=
+ Above} (318)
+ \p{Canonical_Combining_Class: Above} (Short: \p{Ccc=A}) (318)
+ \p{Canonical_Combining_Class: Above_Left} (Short: \p{Ccc=AL}) (3)
+ \p{Canonical_Combining_Class: Above_Right} (Short: \p{Ccc=AR}) (4)
+ \p{Canonical_Combining_Class: AL} \p{Canonical_Combining_Class=
+ Above_Left} (3)
+ \p{Canonical_Combining_Class: AR} \p{Canonical_Combining_Class=
+ Above_Right} (4)
+ \p{Canonical_Combining_Class: ATA} \p{Canonical_Combining_Class=
+ Attached_Above} (1)
+ \p{Canonical_Combining_Class: ATAR} \p{Canonical_Combining_Class=
+ Attached_Above_Right} (9)
+ \p{Canonical_Combining_Class: ATB} \p{Canonical_Combining_Class=
+ Attached_Below} (5)
+ \p{Canonical_Combining_Class: ATBL} \p{Canonical_Combining_Class=
+ Attached_Below_Left} (0)
+ \p{Canonical_Combining_Class: Attached_Above} (Short: \p{Ccc=ATA})
+ (1)
+ \p{Canonical_Combining_Class: Attached_Above_Right} (Short:
+ \p{Ccc=ATAR}) (9)
+ \p{Canonical_Combining_Class: Attached_Below} (Short: \p{Ccc=ATB})
+ (5)
+ \p{Canonical_Combining_Class: Attached_Below_Left} (Short: \p{Ccc=
+ ATBL}) (0)
+ \p{Canonical_Combining_Class: B} \p{Canonical_Combining_Class=
+ Below} (117)
+ \p{Canonical_Combining_Class: Below} (Short: \p{Ccc=B}) (117)
+ \p{Canonical_Combining_Class: Below_Left} (Short: \p{Ccc=BL}) (1)
+ \p{Canonical_Combining_Class: Below_Right} (Short: \p{Ccc=BR}) (4)
+ \p{Canonical_Combining_Class: BL} \p{Canonical_Combining_Class=
+ Below_Left} (1)
+ \p{Canonical_Combining_Class: BR} \p{Canonical_Combining_Class=
+ Below_Right} (4)
+ \p{Canonical_Combining_Class: DA} \p{Canonical_Combining_Class=
+ Double_Above} (5)
+ \p{Canonical_Combining_Class: DB} \p{Canonical_Combining_Class=
+ Double_Below} (3)
+ \p{Canonical_Combining_Class: Double_Above} (Short: \p{Ccc=DA}) (5)
+ \p{Canonical_Combining_Class: Double_Below} (Short: \p{Ccc=DB}) (3)
+ \p{Canonical_Combining_Class: Iota_Subscript} (Short: \p{Ccc=IS})
+ (1)
+ \p{Canonical_Combining_Class: IS} \p{Canonical_Combining_Class=
+ Iota_Subscript} (1)
+ \p{Canonical_Combining_Class: Kana_Voicing} (Short: \p{Ccc=KV}) (2)
+ \p{Canonical_Combining_Class: KV} \p{Canonical_Combining_Class=
+ Kana_Voicing} (2)
+ \p{Canonical_Combining_Class: L} \p{Canonical_Combining_Class=
+ Left} (2)
+ \p{Canonical_Combining_Class: Left} (Short: \p{Ccc=L}) (2)
+ \p{Canonical_Combining_Class: NK} \p{Canonical_Combining_Class=
+ Nukta} (11)
+ \p{Canonical_Combining_Class: Not_Reordered} (Short: \p{Ccc=NR})
+ (1_113_518)
+ \p{Canonical_Combining_Class: NR} \p{Canonical_Combining_Class=
+ Not_Reordered} (1_113_518)
+ \p{Canonical_Combining_Class: Nukta} (Short: \p{Ccc=NK}) (11)
+ \p{Canonical_Combining_Class: OV} \p{Canonical_Combining_Class=
+ Overlay} (26)
+ \p{Canonical_Combining_Class: Overlay} (Short: \p{Ccc=OV}) (26)
+ \p{Canonical_Combining_Class: R} \p{Canonical_Combining_Class=
+ Right} (1)
+ \p{Canonical_Combining_Class: Right} (Short: \p{Ccc=R}) (1)
+ \p{Canonical_Combining_Class: Virama} (Short: \p{Ccc=VR}) (27)
+ \p{Canonical_Combining_Class: VR} \p{Canonical_Combining_Class=
+ Virama} (27)
+ \p{Cans} \p{Canadian_Aboriginal} (= \p{Script=
+ Canadian_Aboriginal}) (710)
+ \p{Cari} \p{Carian} (= \p{Script=Carian}) (NOT
+ \p{Block=Carian}) (49)
+ \p{Carian} \p{Script=Carian} (Short: \p{Cari}; NOT
+ \p{Block=Carian}) (49)
+ \p{Case_Ignorable} \p{Case_Ignorable=Y} (Short: \p{CI}) (1632)
+ \p{Case_Ignorable: N*} (Short: \p{CI=N}, \P{CI}) (1_112_480)
+ \p{Case_Ignorable: Y*} (Short: \p{CI=Y}, \p{CI}) (1632)
+ \p{Cased} \p{Cased=Y} (3408)
+ \p{Cased: N*} (Single: \P{Cased}) (1_110_704)
+ \p{Cased: Y*} (Single: \p{Cased}) (3408)
+ \p{Cased_Letter} \p{General_Category=Cased_Letter} (Short:
+ \p{LC}) (3207)
+ \p{Category: *} \p{General_Category: *}
+ \p{Cc} \p{Cntrl} (= \p{General_Category=Control})
+ (65)
+ \p{Ccc: *} \p{Canonical_Combining_Class: *}
+ \p{CE} \p{Composition_Exclusion} (=
+ \p{Composition_Exclusion=Y}) (81)
+ \p{CE: *} \p{Composition_Exclusion: *}
+ \p{Cf} \p{Format} (= \p{General_Category=Format})
+ (140)
+ \p{Cham} \p{Script=Cham} (NOT \p{Block=Cham}) (83)
+ \p{Changes_When_Casefolded} \p{Changes_When_Casefolded=Y} (Short:
+ \p{CWCF}) (1093)
+ \p{Changes_When_Casefolded: N*} (Short: \p{CWCF=N}, \P{CWCF})
+ (1_113_019)
+ \p{Changes_When_Casefolded: Y*} (Short: \p{CWCF=Y}, \p{CWCF})
+ (1093)
+ \p{Changes_When_Casemapped} \p{Changes_When_Casemapped=Y} (Short:
+ \p{CWCM}) (2110)
+ \p{Changes_When_Casemapped: N*} (Short: \p{CWCM=N}, \P{CWCM})
+ (1_112_002)
+ \p{Changes_When_Casemapped: Y*} (Short: \p{CWCM=Y}, \p{CWCM})
+ (2110)
+ \p{Changes_When_Lowercased} \p{Changes_When_Lowercased=Y} (Short:
+ \p{CWL}) (1029)
+ \p{Changes_When_Lowercased: N*} (Short: \p{CWL=N}, \P{CWL})
+ (1_113_083)
+ \p{Changes_When_Lowercased: Y*} (Short: \p{CWL=Y}, \p{CWL}) (1029)
+ \p{Changes_When_NFKC_Casefolded} \p{Changes_When_NFKC_Casefolded=
+ Y} (Short: \p{CWKCF}) (9740)
+ \p{Changes_When_NFKC_Casefolded: N*} (Short: \p{CWKCF=N},
+ \P{CWKCF}) (1_104_372)
+ \p{Changes_When_NFKC_Casefolded: Y*} (Short: \p{CWKCF=Y},
+ \p{CWKCF}) (9740)
+ \p{Changes_When_Titlecased} \p{Changes_When_Titlecased=Y} (Short:
+ \p{CWT}) (1085)
+ \p{Changes_When_Titlecased: N*} (Short: \p{CWT=N}, \P{CWT})
+ (1_113_027)
+ \p{Changes_When_Titlecased: Y*} (Short: \p{CWT=Y}, \p{CWT}) (1085)
+ \p{Changes_When_Uppercased} \p{Changes_When_Uppercased=Y} (Short:
+ \p{CWU}) (1112)
+ \p{Changes_When_Uppercased: N*} (Short: \p{CWU=N}, \P{CWU})
+ (1_113_000)
+ \p{Changes_When_Uppercased: Y*} (Short: \p{CWU=Y}, \p{CWU}) (1112)
+ \p{Cher} \p{Cherokee} (= \p{Script=Cherokee}) (NOT
+ \p{Block=Cherokee}) (85)
+ \p{Cherokee} \p{Script=Cherokee} (Short: \p{Cher}; NOT
+ \p{Block=Cherokee}) (85)
+ \p{CI} \p{Case_Ignorable} (= \p{Case_Ignorable=
+ Y}) (1632)
+ \p{CI: *} \p{Case_Ignorable: *}
+ X \p{CJK_Compatibility} \p{Block=CJK_Compatibility} (256)
+ X \p{CJK_Compatibility_Forms} \p{Block=CJK_Compatibility_Forms} (32)
+ X \p{CJK_Compatibility_Ideographs} \p{Block=
+ CJK_Compatibility_Ideographs} (512)
+ X \p{CJK_Compatibility_Ideographs_Supplement} \p{Block=
+ CJK_Compatibility_Ideographs_Supplement}
+ (544)
+ X \p{CJK_Radicals_Supplement} \p{Block=CJK_Radicals_Supplement} (128)
+ X \p{CJK_Strokes} \p{Block=CJK_Strokes} (48)
+ X \p{CJK_Symbols_And_Punctuation} \p{Block=
+ CJK_Symbols_And_Punctuation} (64)
+ X \p{CJK_Unified_Ideographs} \p{Block=CJK_Unified_Ideographs}
+ (20_992)
+ X \p{CJK_Unified_Ideographs_Extension_A} \p{Block=
+ CJK_Unified_Ideographs_Extension_A}
+ (6592)
+ X \p{CJK_Unified_Ideographs_Extension_B} \p{Block=
+ CJK_Unified_Ideographs_Extension_B}
+ (42_720)
+ X \p{CJK_Unified_Ideographs_Extension_C} \p{Block=
+ CJK_Unified_Ideographs_Extension_C}
+ (4160)
+ \p{Close_Punctuation} \p{General_Category=Close_Punctuation}
+ (Short: \p{Pe}) (71)
+ \p{Cn} \p{Unassigned} (= \p{General_Category=
+ Unassigned}) (867_235)
+ \p{Cntrl} \p{General_Category=Control} Control
+ characters (Short: \p{Cc}) (65)
+ \p{Co} \p{Private_Use} (= \p{General_Category=
+ Private_Use}) (NOT \p{Private_Use_Area})
+ (137_468)
+ X \p{Combining_Diacritical_Marks} \p{Block=
+ Combining_Diacritical_Marks} (112)
+ X \p{Combining_Diacritical_Marks_For_Symbols} \p{Block=
+ Combining_Diacritical_Marks_For_Symbols}
+ (Short: \p{InCombiningMarksForSymbols})
+ (48)
+ X \p{Combining_Diacritical_Marks_Supplement} \p{Block=
+ Combining_Diacritical_Marks_Supplement}
+ (64)
+ X \p{Combining_Half_Marks} \p{Block=Combining_Half_Marks} (16)
+ X \p{Combining_Marks_For_Symbols}
+ \p{Combining_Diacritical_Marks_For_-
+ Symbols} (= \p{Block=
+ Combining_Diacritical_Marks_For_-
+ Symbols}) (48)
+ \p{Common} \p{Script=Common} (Short: \p{Zyyy}) (5395)
+ X \p{Common_Indic_Number_Forms} \p{Block=Common_Indic_Number_Forms}
+ (16)
+ \p{Comp_Ex} \p{Full_Composition_Exclusion} (=
+ \p{Full_Composition_Exclusion=Y}) (1118)
+ \p{Comp_Ex: *} \p{Full_Composition_Exclusion: *}
+ \p{Composition_Exclusion} \p{Composition_Exclusion=Y} (Short:
+ \p{CE}) (81)
+ \p{Composition_Exclusion: N*} (Short: \p{CE=N}, \P{CE}) (1_114_031)
+ \p{Composition_Exclusion: Y*} (Short: \p{CE=Y}, \p{CE}) (81)
+ \p{Connector_Punctuation} \p{General_Category=
+ Connector_Punctuation} (Short: \p{Pc})
+ (10)
+ \p{Control} \p{Cntrl} (= \p{General_Category=Control})
+ (65)
+ X \p{Control_Pictures} \p{Block=Control_Pictures} (64)
+ \p{Copt} \p{Coptic} (= \p{Script=Coptic}) (NOT
+ \p{Block=Coptic}) (135)
+ \p{Coptic} \p{Script=Coptic} (Short: \p{Copt}; NOT
+ \p{Block=Coptic}) (135)
+ X \p{Counting_Rod_Numerals} \p{Block=Counting_Rod_Numerals} (32)
+ \p{Cprt} \p{Cypriot} (= \p{Script=Cypriot}) (55)
+ \p{Cs} \p{Surrogate} (= \p{General_Category=
+ Surrogate}) (2048)
+ \p{Cuneiform} \p{Script=Cuneiform} (Short: \p{Xsux}; NOT
+ \p{Block=Cuneiform}) (982)
+ X \p{Cuneiform_Numbers_And_Punctuation} \p{Block=
+ Cuneiform_Numbers_And_Punctuation} (128)
+ \p{Currency_Symbol} \p{General_Category=Currency_Symbol}
+ (Short: \p{Sc}) (46)
+ X \p{Currency_Symbols} \p{Block=Currency_Symbols} (48)
+ \p{CWCF} \p{Changes_When_Casefolded} (=
+ \p{Changes_When_Casefolded=Y}) (1093)
+ \p{CWCF: *} \p{Changes_When_Casefolded: *}
+ \p{CWCM} \p{Changes_When_Casemapped} (=
+ \p{Changes_When_Casemapped=Y}) (2110)
+ \p{CWCM: *} \p{Changes_When_Casemapped: *}
+ \p{CWKCF} \p{Changes_When_NFKC_Casefolded} (=
+ \p{Changes_When_NFKC_Casefolded=Y})
+ (9740)
+ \p{CWKCF: *} \p{Changes_When_NFKC_Casefolded: *}
+ \p{CWL} \p{Changes_When_Lowercased} (=
+ \p{Changes_When_Lowercased=Y}) (1029)
+ \p{CWL: *} \p{Changes_When_Lowercased: *}
+ \p{CWT} \p{Changes_When_Titlecased} (=
+ \p{Changes_When_Titlecased=Y}) (1085)
+ \p{CWT: *} \p{Changes_When_Titlecased: *}
+ \p{CWU} \p{Changes_When_Uppercased} (=
+ \p{Changes_When_Uppercased=Y}) (1112)
+ \p{CWU: *} \p{Changes_When_Uppercased: *}
+ \p{Cypriot} \p{Script=Cypriot} (Short: \p{Cprt}) (55)
+ X \p{Cypriot_Syllabary} \p{Block=Cypriot_Syllabary} (64)
+ \p{Cyrillic} \p{Script=Cyrillic} (Short: \p{Cyrl}; NOT
+ \p{Block=Cyrillic}) (404)
+ X \p{Cyrillic_Extended_A} \p{Block=Cyrillic_Extended_A} (32)
+ X \p{Cyrillic_Extended_B} \p{Block=Cyrillic_Extended_B} (96)
+ X \p{Cyrillic_Supplement} \p{Block=Cyrillic_Supplement} (48)
+ X \p{Cyrillic_Supplementary} \p{Cyrillic_Supplement} (= \p{Block=
+ Cyrillic_Supplement}) (48)
+ \p{Cyrl} \p{Cyrillic} (= \p{Script=Cyrillic}) (NOT
+ \p{Block=Cyrillic}) (404)
+ \p{Dash} \p{Dash=Y} (25)
+ \p{Dash: N*} (Single: \P{Dash}) (1_114_087)
+ \p{Dash: Y*} (Single: \p{Dash}) (25)
+ \p{Dash_Punctuation} \p{General_Category=Dash_Punctuation}
+ (Short: \p{Pd}) (21)
+ \p{Decimal_Number} \p{Digit} (= \p{General_Category=
+ Decimal_Number}) (411)
+ \p{Decomposition_Type: Can} \p{Decomposition_Type=Canonical}
+ (13_221)
+ \p{Decomposition_Type: Canonical} (Short: \p{Dt=Can}) (13_221)
+ \p{Decomposition_Type: Circle} (Short: \p{Dt=Enc}) (238)
+ \p{Decomposition_Type: Com} \p{Decomposition_Type=Compat} (720)
+ \p{Decomposition_Type: Compat} (Short: \p{Dt=Com}) (720)
+ \p{Decomposition_Type: Enc} \p{Decomposition_Type=Circle} (238)
+ \p{Decomposition_Type: Fin} \p{Decomposition_Type=Final} (240)
+ \p{Decomposition_Type: Final} (Short: \p{Dt=Fin}) (240)
+ \p{Decomposition_Type: Font} (Short: \p{Dt=Font}) (1043)
+ \p{Decomposition_Type: Fra} \p{Decomposition_Type=Fraction} (20)
+ \p{Decomposition_Type: Fraction} (Short: \p{Dt=Fra}) (20)
+ \p{Decomposition_Type: Init} \p{Decomposition_Type=Initial} (171)
+ \p{Decomposition_Type: Initial} (Short: \p{Dt=Init}) (171)
+ \p{Decomposition_Type: Iso} \p{Decomposition_Type=Isolated} (238)
+ \p{Decomposition_Type: Isolated} (Short: \p{Dt=Iso}) (238)
+ \p{Decomposition_Type: Med} \p{Decomposition_Type=Medial} (82)
+ \p{Decomposition_Type: Medial} (Short: \p{Dt=Med}) (82)
+ \p{Decomposition_Type: Nar} \p{Decomposition_Type=Narrow} (122)
+ \p{Decomposition_Type: Narrow} (Short: \p{Dt=Nar}) (122)
+ \p{Decomposition_Type: Nb} \p{Decomposition_Type=Nobreak} (5)
+ \p{Decomposition_Type: Nobreak} (Short: \p{Dt=Nb}) (5)
+ \p{Decomposition_Type: Non_Canon} \p{Decomposition_Type=
+ Non_Canonical} (Perl extension) (3467)
+ \p{Decomposition_Type: Non_Canonical} Union of all non-canonical
+ decompositions (Short: \p{Dt=NonCanon})
+ (Perl extension) (3467)
+ \p{Decomposition_Type: None} (Short: \p{Dt=None}) (1_097_424)
+ \p{Decomposition_Type: Small} (Short: \p{Dt=Sml}) (26)
+ \p{Decomposition_Type: Sml} \p{Decomposition_Type=Small} (26)
+ \p{Decomposition_Type: Sqr} \p{Decomposition_Type=Square} (251)
+ \p{Decomposition_Type: Square} (Short: \p{Dt=Sqr}) (251)
+ \p{Decomposition_Type: Sub} (Short: \p{Dt=Sub}) (30)
+ \p{Decomposition_Type: Sup} \p{Decomposition_Type=Super} (142)
+ \p{Decomposition_Type: Super} (Short: \p{Dt=Sup}) (142)
+ \p{Decomposition_Type: Vert} \p{Decomposition_Type=Vertical} (35)
+ \p{Decomposition_Type: Vertical} (Short: \p{Dt=Vert}) (35)
+ \p{Decomposition_Type: Wide} (Short: \p{Dt=Wide}) (104)
+ \p{Default_Ignorable_Code_Point} \p{Default_Ignorable_Code_Point=
+ Y} (Short: \p{DI}) (4167)
+ \p{Default_Ignorable_Code_Point: N*} (Short: \p{DI=N}, \P{DI})
+ (1_109_945)
+ \p{Default_Ignorable_Code_Point: Y*} (Short: \p{DI=Y}, \p{DI})
+ (4167)
+ \p{Dep} \p{Deprecated} (= \p{Deprecated=Y}) (110)
+ \p{Dep: *} \p{Deprecated: *}
+ \p{Deprecated} \p{Deprecated=Y} (Short: \p{Dep}) (110)
+ \p{Deprecated: N*} (Short: \p{Dep=N}, \P{Dep}) (1_114_002)
+ \p{Deprecated: Y*} (Short: \p{Dep=Y}, \p{Dep}) (110)
+ \p{Deseret} \p{Script=Deseret} (Short: \p{Dsrt}) (80)
+ \p{Deva} \p{Devanagari} (= \p{Script=Devanagari})
+ (NOT \p{Block=Devanagari}) (140)
+ \p{Devanagari} \p{Script=Devanagari} (Short: \p{Deva};
+ NOT \p{Block=Devanagari}) (140)
+ X \p{Devanagari_Extended} \p{Block=Devanagari_Extended} (32)
+ \p{DI} \p{Default_Ignorable_Code_Point} (=
+ \p{Default_Ignorable_Code_Point=Y})
+ (4167)
+ \p{DI: *} \p{Default_Ignorable_Code_Point: *}
+ \p{Dia} \p{Diacritic} (= \p{Diacritic=Y}) (639)
+ \p{Dia: *} \p{Diacritic: *}
+ \p{Diacritic} \p{Diacritic=Y} (Short: \p{Dia}) (639)
+ \p{Diacritic: N*} (Short: \p{Dia=N}, \P{Dia}) (1_113_473)
+ \p{Diacritic: Y*} (Short: \p{Dia=Y}, \p{Dia}) (639)
+ \p{Digit} \p{General_Category=Decimal_Number} \d,
+ extended beyond just [0-9] (Short:
+ \p{Nd}) (411)
+ X \p{Dingbats} \p{Block=Dingbats} (192)
+ X \p{Domino_Tiles} \p{Block=Domino_Tiles} (112)
+ \p{Dsrt} \p{Deseret} (= \p{Script=Deseret}) (80)
+ \p{Dt: *} \p{Decomposition_Type: *}
+ \p{Ea: *} \p{East_Asian_Width: *}
+ \p{East_Asian_Width: A} \p{East_Asian_Width=Ambiguous} (138_666)
+ \p{East_Asian_Width: Ambiguous} (Short: \p{Ea=A}) (138_666)
+ \p{East_Asian_Width: F} \p{East_Asian_Width=Fullwidth} (104)
+ \p{East_Asian_Width: Fullwidth} (Short: \p{Ea=F}) (104)
+ \p{East_Asian_Width: H} \p{East_Asian_Width=Halfwidth} (123)
+ \p{East_Asian_Width: Halfwidth} (Short: \p{Ea=H}) (123)
+ \p{East_Asian_Width: N} \p{East_Asian_Width=Neutral} (801_909)
+ \p{East_Asian_Width: Na} \p{East_Asian_Width=Narrow} (111)
+ \p{East_Asian_Width: Narrow} (Short: \p{Ea=Na}) (111)
+ \p{East_Asian_Width: Neutral} (Short: \p{Ea=N}) (801_909)
+ \p{East_Asian_Width: W} \p{East_Asian_Width=Wide} (173_199)
+ \p{East_Asian_Width: Wide} (Short: \p{Ea=W}) (173_199)
+ \p{Egyp} \p{Egyptian_Hieroglyphs} (= \p{Script=
+ Egyptian_Hieroglyphs}) (NOT \p{Block=
+ Egyptian_Hieroglyphs}) (1071)
+ \p{Egyptian_Hieroglyphs} \p{Script=Egyptian_Hieroglyphs} (Short:
+ \p{Egyp}; NOT \p{Block=
+ Egyptian_Hieroglyphs}) (1071)
+ X \p{Enclosed_Alphanumeric_Supplement} \p{Block=
+ Enclosed_Alphanumeric_Supplement} (256)
+ X \p{Enclosed_Alphanumerics} \p{Block=Enclosed_Alphanumerics} (160)
+ X \p{Enclosed_CJK_Letters_And_Months} \p{Block=
+ Enclosed_CJK_Letters_And_Months} (256)
+ X \p{Enclosed_Ideographic_Supplement} \p{Block=
+ Enclosed_Ideographic_Supplement} (256)
+ \p{Enclosing_Mark} \p{General_Category=Enclosing_Mark}
+ (Short: \p{Me}) (13)
+ \p{Ethi} \p{Ethiopic} (= \p{Script=Ethiopic}) (NOT
+ \p{Block=Ethiopic}) (461)
+ \p{Ethiopic} \p{Script=Ethiopic} (Short: \p{Ethi}; NOT
+ \p{Block=Ethiopic}) (461)
+ X \p{Ethiopic_Extended} \p{Block=Ethiopic_Extended} (96)
+ X \p{Ethiopic_Supplement} \p{Block=Ethiopic_Supplement} (32)
+ \p{Ext} \p{Extender} (= \p{Extender=Y}) (28)
+ \p{Ext: *} \p{Extender: *}
+ \p{Extender} \p{Extender=Y} (Short: \p{Ext}) (28)
+ \p{Extender: N*} (Short: \p{Ext=N}, \P{Ext}) (1_114_084)
+ \p{Extender: Y*} (Short: \p{Ext=Y}, \p{Ext}) (28)
+ \p{Final_Punctuation} \p{General_Category=Final_Punctuation}
+ (Short: \p{Pf}) (10)
+ \p{Format} \p{General_Category=Format} (Short:
+ \p{Cf}) (140)
+ \p{Full_Composition_Exclusion} \p{Full_Composition_Exclusion=Y}
+ (Short: \p{CompEx}) (1118)
+ \p{Full_Composition_Exclusion: N*} (Short: \p{CompEx=N},
+ \P{CompEx}) (1_112_994)
+ \p{Full_Composition_Exclusion: Y*} (Short: \p{CompEx=Y},
+ \p{CompEx}) (1118)
+ \p{Gc: *} \p{General_Category: *}
+ \p{GCB: *} \p{Grapheme_Cluster_Break: *}
+ \p{General_Category: C} \p{General_Category=Other} (1_006_956)
+ \p{General_Category: Cased_Letter} [\p{Ll}\p{Lu}\p{Lt}] (Short:
+ \p{Gc=LC}, \p{LC}) (3207)
+ \p{General_Category: Cc} \p{General_Category=Control} (65)
+ \p{General_Category: Cf} \p{General_Category=Format} (140)
+ \p{General_Category: Close_Punctuation} (Short: \p{Gc=Pe}, \p{Pe})
+ (71)
+ \p{General_Category: Cn} \p{General_Category=Unassigned} (867_235)
+ \p{General_Category: Cntrl} \p{General_Category=Control} (65)
+ \p{General_Category: Co} \p{General_Category=Private_Use} (137_468)
+ \p{General_Category: Connector_Punctuation} (Short: \p{Gc=Pc},
+ \p{Pc}) (10)
+ \p{General_Category: Control} (Short: \p{Gc=Cc}, \p{Cc}) (65)
+ \p{General_Category: Cs} \p{General_Category=Surrogate} (2048)
+ \p{General_Category: Currency_Symbol} (Short: \p{Gc=Sc}, \p{Sc})
+ (46)
+ \p{General_Category: Dash_Punctuation} (Short: \p{Gc=Pd}, \p{Pd})
+ (21)
+ \p{General_Category: Decimal_Number} (Short: \p{Gc=Nd}, \p{Nd})
+ (411)
+ \p{General_Category: Digit} \p{General_Category=Decimal_Number}
+ (411)
+ \p{General_Category: Enclosing_Mark} (Short: \p{Gc=Me}, \p{Me})
+ (13)
+ \p{General_Category: Final_Punctuation} (Short: \p{Gc=Pf}, \p{Pf})
+ (10)
+ \p{General_Category: Format} (Short: \p{Gc=Cf}, \p{Cf}) (140)
+ \p{General_Category: Initial_Punctuation} (Short: \p{Gc=Pi},
+ \p{Pi}) (12)
+ \p{General_Category: L} \p{General_Category=Letter} (99_537)
+ X \p{General_Category: L&} \p{General_Category=Cased_Letter} (3207)
+ X \p{General_Category: L_} \p{General_Category=Cased_Letter} (3207)
+ \p{General_Category: LC} \p{General_Category=Cased_Letter} (3207)
+ \p{General_Category: Letter} (Short: \p{Gc=L}, \p{L}) (99_537)
+ \p{General_Category: Letter_Number} (Short: \p{Gc=Nl}, \p{Nl})
+ (224)
+ \p{General_Category: Line_Separator} (Short: \p{Gc=Zl}, \p{Zl}) (1)
+ \p{General_Category: Ll} \p{General_Category=Lowercase_Letter}
+ (1749)
+ \p{General_Category: Lm} \p{General_Category=Modifier_Letter} (202)
+ \p{General_Category: Lo} \p{General_Category=Other_Letter} (96_128)
+ \p{General_Category: Lowercase_Letter} (Short: \p{Gc=Ll}, \p{Ll})
+ (1749)
+ \p{General_Category: Lt} \p{General_Category=Titlecase_Letter} (31)
+ \p{General_Category: Lu} \p{General_Category=Uppercase_Letter}
+ (1427)
+ \p{General_Category: M} \p{General_Category=Mark} (1451)
+ \p{General_Category: Mark} (Short: \p{Gc=M}, \p{M}) (1451)
+ \p{General_Category: Math_Symbol} (Short: \p{Gc=Sm}, \p{Sm}) (945)
+ \p{General_Category: Mc} \p{General_Category=Spacing_Mark} (276)
+ \p{General_Category: Me} \p{General_Category=Enclosing_Mark} (13)
+ \p{General_Category: Mn} \p{General_Category=Nonspacing_Mark}
+ (1162)
+ \p{General_Category: Modifier_Letter} (Short: \p{Gc=Lm}, \p{Lm})
+ (202)
+ \p{General_Category: Modifier_Symbol} (Short: \p{Gc=Sk}, \p{Sk})
+ (99)
+ \p{General_Category: N} \p{General_Category=Number} (1064)
+ \p{General_Category: Nd} \p{General_Category=Decimal_Number} (411)
+ \p{General_Category: Nl} \p{General_Category=Letter_Number} (224)
+ \p{General_Category: No} \p{General_Category=Other_Number} (429)
+ \p{General_Category: Nonspacing_Mark} (Short: \p{Gc=Mn}, \p{Mn})
+ (1162)
+ \p{General_Category: Number} (Short: \p{Gc=N}, \p{N}) (1064)
+ \p{General_Category: Open_Punctuation} (Short: \p{Gc=Ps}, \p{Ps})
+ (72)
+ \p{General_Category: Other} (Short: \p{Gc=C}, \p{C}) (1_006_956)
+ \p{General_Category: Other_Letter} (Short: \p{Gc=Lo}, \p{Lo})
+ (96_128)
+ \p{General_Category: Other_Number} (Short: \p{Gc=No}, \p{No}) (429)
+ \p{General_Category: Other_Punctuation} (Short: \p{Gc=Po}, \p{Po})
+ (389)
+ \p{General_Category: Other_Symbol} (Short: \p{Gc=So}, \p{So})
+ (3409)
+ \p{General_Category: P} \p{General_Category=Punctuation} (585)
+ \p{General_Category: Paragraph_Separator} (Short: \p{Gc=Zp},
+ \p{Zp}) (1)
+ \p{General_Category: Pc} \p{General_Category=
+ Connector_Punctuation} (10)
+ \p{General_Category: Pd} \p{General_Category=Dash_Punctuation} (21)
+ \p{General_Category: Pe} \p{General_Category=Close_Punctuation}
+ (71)
+ \p{General_Category: Pf} \p{General_Category=Final_Punctuation}
+ (10)
+ \p{General_Category: Pi} \p{General_Category=Initial_Punctuation}
+ (12)
+ \p{General_Category: Po} \p{General_Category=Other_Punctuation}
+ (389)
+ \p{General_Category: Private_Use} (Short: \p{Gc=Co}, \p{Co})
+ (137_468)
+ \p{General_Category: Ps} \p{General_Category=Open_Punctuation} (72)
+ \p{General_Category: Punct} \p{General_Category=Punctuation} (585)
+ \p{General_Category: Punctuation} (Short: \p{Gc=P}, \p{P}) (585)
+ \p{General_Category: S} \p{General_Category=Symbol} (4499)
+ \p{General_Category: Sc} \p{General_Category=Currency_Symbol} (46)
+ \p{General_Category: Separator} (Short: \p{Gc=Z}, \p{Z}) (20)
+ \p{General_Category: Sk} \p{General_Category=Modifier_Symbol} (99)
+ \p{General_Category: Sm} \p{General_Category=Math_Symbol} (945)
+ \p{General_Category: So} \p{General_Category=Other_Symbol} (3409)
+ \p{General_Category: Space_Separator} (Short: \p{Gc=Zs}, \p{Zs})
+ (18)
+ \p{General_Category: Spacing_Mark} (Short: \p{Gc=Mc}, \p{Mc}) (276)
+ \p{General_Category: Surrogate} Mostly not usable in Perl. (Short:
+ \p{Gc=Cs}, \p{Cs}) (2048)
+ \p{General_Category: Symbol} (Short: \p{Gc=S}, \p{S}) (4499)
+ \p{General_Category: Titlecase_Letter} (Short: \p{Gc=Lt}, \p{Lt})
+ (31)
+ \p{General_Category: Unassigned} (Short: \p{Gc=Cn}, \p{Cn})
+ (867_235)
+ \p{General_Category: Uppercase_Letter} (Short: \p{Gc=Lu}, \p{Lu})
+ (1427)
+ \p{General_Category: Z} \p{General_Category=Separator} (20)
+ \p{General_Category: Zl} \p{General_Category=Line_Separator} (1)
+ \p{General_Category: Zp} \p{General_Category=Paragraph_Separator}
+ (1)
+ \p{General_Category: Zs} \p{General_Category=Space_Separator} (18)
+ X \p{General_Punctuation} \p{Block=General_Punctuation} (112)
+ X \p{Geometric_Shapes} \p{Block=Geometric_Shapes} (96)
+ \p{Geor} \p{Georgian} (= \p{Script=Georgian}) (NOT
+ \p{Block=Georgian}) (120)
+ \p{Georgian} \p{Script=Georgian} (Short: \p{Geor}; NOT
+ \p{Block=Georgian}) (120)
+ X \p{Georgian_Supplement} \p{Block=Georgian_Supplement} (48)
+ \p{Glag} \p{Glagolitic} (= \p{Script=Glagolitic})
+ (NOT \p{Block=Glagolitic}) (94)
+ \p{Glagolitic} \p{Script=Glagolitic} (Short: \p{Glag};
+ NOT \p{Block=Glagolitic}) (94)
+ \p{Goth} \p{Gothic} (= \p{Script=Gothic}) (NOT
+ \p{Block=Gothic}) (27)
+ \p{Gothic} \p{Script=Gothic} (Short: \p{Goth}; NOT
+ \p{Block=Gothic}) (27)
+ \p{Gr_Base} \p{Grapheme_Base} (= \p{Grapheme_Base=Y})
+ (105_958)
+ \p{Gr_Base: *} \p{Grapheme_Base: *}
+ \p{Gr_Ext} \p{Grapheme_Extend} (= \p{Grapheme_Extend=
+ Y}) (1198)
+ \p{Gr_Ext: *} \p{Grapheme_Extend: *}
+ \p{Graph} Characters that are graphical (244_744)
+ \p{Grapheme_Base} \p{Grapheme_Base=Y} (Short: \p{GrBase})
+ (105_958)
+ \p{Grapheme_Base: N*} (Short: \p{GrBase=N}, \P{GrBase})
+ (1_008_154)
+ \p{Grapheme_Base: Y*} (Short: \p{GrBase=Y}, \p{GrBase}) (105_958)
+ \p{Grapheme_Cluster_Break: CN} \p{Grapheme_Cluster_Break=Control}
+ (203)
+ \p{Grapheme_Cluster_Break: Control} (Short: \p{GCB=CN}) (203)
+ \p{Grapheme_Cluster_Break: CR} (Short: \p{GCB=CR}) (1)
+ \p{Grapheme_Cluster_Break: EX} \p{Grapheme_Cluster_Break=Extend}
+ (1205)
+ \p{Grapheme_Cluster_Break: Extend} (Short: \p{GCB=EX}) (1205)
+ \p{Grapheme_Cluster_Break: L} (Short: \p{GCB=L}) (125)
+ \p{Grapheme_Cluster_Break: LF} (Short: \p{GCB=LF}) (1)
+ \p{Grapheme_Cluster_Break: LV} (Short: \p{GCB=LV}) (399)
+ \p{Grapheme_Cluster_Break: LVT} (Short: \p{GCB=LVT}) (10_773)
+ \p{Grapheme_Cluster_Break: Other} (Short: \p{GCB=XX}) (1_100_901)
+ \p{Grapheme_Cluster_Break: PP} \p{Grapheme_Cluster_Break=Prepend}
+ (15)
+ \p{Grapheme_Cluster_Break: Prepend} (Short: \p{GCB=PP}) (15)
+ \p{Grapheme_Cluster_Break: SM} \p{Grapheme_Cluster_Break=
+ SpacingMark} (257)
+ \p{Grapheme_Cluster_Break: SpacingMark} (Short: \p{GCB=SM}) (257)
+ \p{Grapheme_Cluster_Break: T} (Short: \p{GCB=T}) (137)
+ \p{Grapheme_Cluster_Break: V} (Short: \p{GCB=V}) (95)
+ \p{Grapheme_Cluster_Break: XX} \p{Grapheme_Cluster_Break=Other}
+ (1_100_901)
+ \p{Grapheme_Extend} \p{Grapheme_Extend=Y} (Short: \p{GrExt})
+ (1198)
+ \p{Grapheme_Extend: N*} (Short: \p{GrExt=N}, \P{GrExt}) (1_112_914)
+ \p{Grapheme_Extend: Y*} (Short: \p{GrExt=Y}, \p{GrExt}) (1198)
+ \p{Greek} \p{Script=Greek} (Short: \p{Grek}; NOT
+ \p{Greek_And_Coptic}) (511)
+ X \p{Greek_And_Coptic} \p{Block=Greek_And_Coptic} (Short:
+ \p{InGreek}) (144)
+ X \p{Greek_Extended} \p{Block=Greek_Extended} (256)
+ \p{Grek} \p{Greek} (= \p{Script=Greek}) (NOT
+ \p{Greek_And_Coptic}) (511)
+ \p{Gujarati} \p{Script=Gujarati} (Short: \p{Gujr}; NOT
+ \p{Block=Gujarati}) (83)
+ \p{Gujr} \p{Gujarati} (= \p{Script=Gujarati}) (NOT
+ \p{Block=Gujarati}) (83)
+ \p{Gurmukhi} \p{Script=Gurmukhi} (Short: \p{Guru}; NOT
+ \p{Block=Gurmukhi}) (79)
+ \p{Guru} \p{Gurmukhi} (= \p{Script=Gurmukhi}) (NOT
+ \p{Block=Gurmukhi}) (79)
+ X \p{Halfwidth_And_Fullwidth_Forms} \p{Block=
+ Halfwidth_And_Fullwidth_Forms} (240)
+ \p{Han} \p{Script=Han} (75_738)
+ \p{Hang} \p{Hangul} (= \p{Script=Hangul}) (11_737)
+ \p{Hangul} \p{Script=Hangul} (Short: \p{Hang})
+ (11_737)
+ X \p{Hangul_Compatibility_Jamo} \p{Block=Hangul_Compatibility_Jamo}
+ (96)
+ X \p{Hangul_Jamo} \p{Block=Hangul_Jamo} (256)
+ X \p{Hangul_Jamo_Extended_A} \p{Block=Hangul_Jamo_Extended_A} (32)
+ X \p{Hangul_Jamo_Extended_B} \p{Block=Hangul_Jamo_Extended_B} (80)
+ \p{Hangul_Syllable_Type: L} \p{Hangul_Syllable_Type=Leading_Jamo}
+ (125)
+ \p{Hangul_Syllable_Type: Leading_Jamo} (Short: \p{Hst=L}) (125)
+ \p{Hangul_Syllable_Type: LV} \p{Hangul_Syllable_Type=LV_Syllable}
+ (399)
+ \p{Hangul_Syllable_Type: LV_Syllable} (Short: \p{Hst=LV}) (399)
+ \p{Hangul_Syllable_Type: LVT} \p{Hangul_Syllable_Type=
+ LVT_Syllable} (10_773)
+ \p{Hangul_Syllable_Type: LVT_Syllable} (Short: \p{Hst=LVT})
+ (10_773)
+ \p{Hangul_Syllable_Type: NA} \p{Hangul_Syllable_Type=
+ Not_Applicable} (1_102_583)
+ \p{Hangul_Syllable_Type: Not_Applicable} (Short: \p{Hst=NA})
+ (1_102_583)
+ \p{Hangul_Syllable_Type: T} \p{Hangul_Syllable_Type=Trailing_Jamo}
+ (137)
+ \p{Hangul_Syllable_Type: Trailing_Jamo} (Short: \p{Hst=T}) (137)
+ \p{Hangul_Syllable_Type: V} \p{Hangul_Syllable_Type=Vowel_Jamo}
+ (95)
+ \p{Hangul_Syllable_Type: Vowel_Jamo} (Short: \p{Hst=V}) (95)
+ X \p{Hangul_Syllables} \p{Block=Hangul_Syllables} (11_184)
+ \p{Hani} \p{Han} (= \p{Script=Han}) (75_738)
+ \p{Hano} \p{Hanunoo} (= \p{Script=Hanunoo}) (NOT
+ \p{Block=Hanunoo}) (21)
+ \p{Hanunoo} \p{Script=Hanunoo} (Short: \p{Hano}; NOT
+ \p{Block=Hanunoo}) (21)
+ \p{Hebr} \p{Hebrew} (= \p{Script=Hebrew}) (NOT
+ \p{Block=Hebrew}) (133)
+ \p{Hebrew} \p{Script=Hebrew} (Short: \p{Hebr}; NOT
+ \p{Block=Hebrew}) (133)
+ \p{Hex} \p{XDigit} (= \p{Hex_Digit=Y}) (44)
+ \p{Hex: *} \p{Hex_Digit: *}
+ \p{Hex_Digit} \p{XDigit} (= \p{Hex_Digit=Y}) (44)
+ \p{Hex_Digit: N*} (Short: \p{Hex=N}, \P{Hex}) (1_114_068)
+ \p{Hex_Digit: Y*} (Short: \p{Hex=Y}, \p{Hex}) (44)
+ X \p{High_Private_Use_Surrogates} \p{Block=
+ High_Private_Use_Surrogates} (128)
+ X \p{High_Surrogates} \p{Block=High_Surrogates} (896)
+ \p{Hira} \p{Hiragana} (= \p{Script=Hiragana}) (NOT
+ \p{Block=Hiragana}) (90)
+ \p{Hiragana} \p{Script=Hiragana} (Short: \p{Hira}; NOT
+ \p{Block=Hiragana}) (90)
+ \p{HorizSpace} \p{Blank} (19)
+ \p{Hst: *} \p{Hangul_Syllable_Type: *}
+ S \p{Hyphen} \p{Hyphen=Y} (11)
+ S \p{Hyphen: N*} Use the Line_Break property instead; see
+ www.unicode.org/reports/tr14 (Single:
+ \P{Hyphen}) (1_114_101)
+ S \p{Hyphen: Y*} Use the Line_Break property instead; see
+ www.unicode.org/reports/tr14 (Single:
+ \p{Hyphen}) (11)
+ \p{ID_Continue} \p{ID_Continue=Y} (Short: \p{IDC})
+ (101_634)
+ \p{ID_Continue: N*} (Short: \p{IDC=N}, \P{IDC}) (1_012_478)
+ \p{ID_Continue: Y*} (Short: \p{IDC=Y}, \p{IDC}) (101_634)
+ \p{ID_Start} \p{ID_Start=Y} (Short: \p{IDS}) (99_764)
+ \p{ID_Start: N*} (Short: \p{IDS=N}, \P{IDS}) (1_014_348)
+ \p{ID_Start: Y*} (Short: \p{IDS=Y}, \p{IDS}) (99_764)
+ \p{IDC} \p{ID_Continue} (= \p{ID_Continue=Y})
+ (101_634)
+ \p{IDC: *} \p{ID_Continue: *}
+ \p{Ideo} \p{Ideographic} (= \p{Ideographic=Y})
+ (75_408)
+ \p{Ideo: *} \p{Ideographic: *}
+ \p{Ideographic} \p{Ideographic=Y} (Short: \p{Ideo})
+ (75_408)
+ \p{Ideographic: N*} (Short: \p{Ideo=N}, \P{Ideo}) (1_038_704)
+ \p{Ideographic: Y*} (Short: \p{Ideo=Y}, \p{Ideo}) (75_408)
+ X \p{Ideographic_Description_Characters} \p{Block=
+ Ideographic_Description_Characters} (16)
+ \p{IDS} \p{ID_Start} (= \p{ID_Start=Y}) (99_764)
+ \p{IDS: *} \p{ID_Start: *}
+ \p{IDS_Binary_Operator} \p{IDS_Binary_Operator=Y} (Short:
+ \p{IDSB}) (10)
+ \p{IDS_Binary_Operator: N*} (Short: \p{IDSB=N}, \P{IDSB})
+ (1_114_102)
+ \p{IDS_Binary_Operator: Y*} (Short: \p{IDSB=Y}, \p{IDSB}) (10)
+ \p{IDS_Trinary_Operator} \p{IDS_Trinary_Operator=Y} (Short:
+ \p{IDST}) (2)
+ \p{IDS_Trinary_Operator: N*} (Short: \p{IDST=N}, \P{IDST})
+ (1_114_110)
+ \p{IDS_Trinary_Operator: Y*} (Short: \p{IDST=Y}, \p{IDST}) (2)
+ \p{IDSB} \p{IDS_Binary_Operator} (=
+ \p{IDS_Binary_Operator=Y}) (10)
+ \p{IDSB: *} \p{IDS_Binary_Operator: *}
+ \p{IDST} \p{IDS_Trinary_Operator} (=
+ \p{IDS_Trinary_Operator=Y}) (2)
+ \p{IDST: *} \p{IDS_Trinary_Operator: *}
+ \p{Imperial_Aramaic} \p{Script=Imperial_Aramaic} (Short:
+ \p{Armi}; NOT \p{Block=
+ Imperial_Aramaic}) (31)
+ \p{In: *} \p{Present_In: *} (Perl extension)
+ \p{In_*} \p{Block: *}
+ \p{Inherited} \p{Script=Inherited} (Short: \p{Zinh})
+ (523)
+ \p{Initial_Punctuation} \p{General_Category=Initial_Punctuation}
+ (Short: \p{Pi}) (12)
+ \p{Inscriptional_Pahlavi} \p{Script=Inscriptional_Pahlavi} (Short:
+ \p{Phli}; NOT \p{Block=
+ Inscriptional_Pahlavi}) (27)
+ \p{Inscriptional_Parthian} \p{Script=Inscriptional_Parthian}
+ (Short: \p{Prti}; NOT \p{Block=
+ Inscriptional_Parthian}) (30)
+ X \p{IPA_Extensions} \p{Block=IPA_Extensions} (96)
+ \p{Is_*} \p{*} (Any exceptions are individually
+ noted beginning with the word NOT.) If
+ an entry has flag(s) at its beginning,
+ like 'D', the 'Is_' form has the same
+ flag(s)
+ \p{Ital} \p{Old_Italic} (= \p{Script=Old_Italic})
+ (NOT \p{Block=Old_Italic}) (35)
+ \p{Java} \p{Javanese} (= \p{Script=Javanese}) (NOT
+ \p{Block=Javanese}) (91)
+ \p{Javanese} \p{Script=Javanese} (Short: \p{Java}; NOT
+ \p{Block=Javanese}) (91)
+ \p{Jg: *} \p{Joining_Group: *}
+ \p{Join_C} \p{Join_Control} (= \p{Join_Control=Y}) (2)
+ \p{Join_C: *} \p{Join_Control: *}
+ \p{Join_Control} \p{Join_Control=Y} (Short: \p{JoinC}) (2)
+ \p{Join_Control: N*} (Short: \p{JoinC=N}, \P{JoinC}) (1_114_110)
+ \p{Join_Control: Y*} (Short: \p{JoinC=Y}, \p{JoinC}) (2)
+ \p{Joining_Group: Ain} (Short: \p{Jg=Ain}) (7)
+ \p{Joining_Group: Alaph} (Short: \p{Jg=Alaph}) (1)
+ \p{Joining_Group: Alef} (Short: \p{Jg=Alef}) (10)
+ \p{Joining_Group: Beh} (Short: \p{Jg=Beh}) (19)
+ \p{Joining_Group: Beth} (Short: \p{Jg=Beth}) (2)
+ \p{Joining_Group: Burushaski_Yeh_Barree} (Short: \p{Jg=
+ BurushaskiYehBarree}) (2)
+ \p{Joining_Group: Dal} (Short: \p{Jg=Dal}) (14)
+ \p{Joining_Group: Dalath_Rish} (Short: \p{Jg=DalathRish}) (4)
+ \p{Joining_Group: E} (Short: \p{Jg=E}) (1)
+ \p{Joining_Group: Farsi_Yeh} (Short: \p{Jg=FarsiYeh}) (7)
+ \p{Joining_Group: Fe} (Short: \p{Jg=Fe}) (1)
+ \p{Joining_Group: Feh} (Short: \p{Jg=Feh}) (9)
+ \p{Joining_Group: Final_Semkath} (Short: \p{Jg=FinalSemkath}) (1)
+ \p{Joining_Group: Gaf} (Short: \p{Jg=Gaf}) (13)
+ \p{Joining_Group: Gamal} (Short: \p{Jg=Gamal}) (3)
+ \p{Joining_Group: Hah} (Short: \p{Jg=Hah}) (17)
+ \p{Joining_Group: Hamza_On_Heh_Goal} (Short: \p{Jg=
+ HamzaOnHehGoal}) (1)
+ \p{Joining_Group: He} (Short: \p{Jg=He}) (1)
+ \p{Joining_Group: Heh} (Short: \p{Jg=Heh}) (1)
+ \p{Joining_Group: Heh_Goal} (Short: \p{Jg=HehGoal}) (2)
+ \p{Joining_Group: Heth} (Short: \p{Jg=Heth}) (1)
+ \p{Joining_Group: Kaf} (Short: \p{Jg=Kaf}) (5)
+ \p{Joining_Group: Kaph} (Short: \p{Jg=Kaph}) (1)
+ \p{Joining_Group: Khaph} (Short: \p{Jg=Khaph}) (1)
+ \p{Joining_Group: Knotted_Heh} (Short: \p{Jg=KnottedHeh}) (2)
+ \p{Joining_Group: Lam} (Short: \p{Jg=Lam}) (6)
+ \p{Joining_Group: Lamadh} (Short: \p{Jg=Lamadh}) (1)
+ \p{Joining_Group: Meem} (Short: \p{Jg=Meem}) (3)
+ \p{Joining_Group: Mim} (Short: \p{Jg=Mim}) (1)
+ \p{Joining_Group: No_Joining_Group} (Short: \p{Jg=NoJoiningGroup})
+ (1_113_883)
+ \p{Joining_Group: Noon} (Short: \p{Jg=Noon}) (8)
+ \p{Joining_Group: Nun} (Short: \p{Jg=Nun}) (1)
+ \p{Joining_Group: Nya} (Short: \p{Jg=Nya}) (1)
+ \p{Joining_Group: Pe} (Short: \p{Jg=Pe}) (1)
+ \p{Joining_Group: Qaf} (Short: \p{Jg=Qaf}) (4)
+ \p{Joining_Group: Qaph} (Short: \p{Jg=Qaph}) (1)
+ \p{Joining_Group: Reh} (Short: \p{Jg=Reh}) (16)
+ \p{Joining_Group: Reversed_Pe} (Short: \p{Jg=ReversedPe}) (1)
+ \p{Joining_Group: Sad} (Short: \p{Jg=Sad}) (5)
+ \p{Joining_Group: Sadhe} (Short: \p{Jg=Sadhe}) (1)
+ \p{Joining_Group: Seen} (Short: \p{Jg=Seen}) (11)
+ \p{Joining_Group: Semkath} (Short: \p{Jg=Semkath}) (1)
+ \p{Joining_Group: Shin} (Short: \p{Jg=Shin}) (1)
+ \p{Joining_Group: Swash_Kaf} (Short: \p{Jg=SwashKaf}) (1)
+ \p{Joining_Group: Syriac_Waw} (Short: \p{Jg=SyriacWaw}) (1)
+ \p{Joining_Group: Tah} (Short: \p{Jg=Tah}) (3)
+ \p{Joining_Group: Taw} (Short: \p{Jg=Taw}) (1)
+ \p{Joining_Group: Teh_Marbuta} (Short: \p{Jg=TehMarbuta}) (3)
+ \p{Joining_Group: Teth} (Short: \p{Jg=Teth}) (2)
+ \p{Joining_Group: Waw} (Short: \p{Jg=Waw}) (15)
+ \p{Joining_Group: Yeh} (Short: \p{Jg=Yeh}) (7)
+ \p{Joining_Group: Yeh_Barree} (Short: \p{Jg=YehBarree}) (2)
+ \p{Joining_Group: Yeh_With_Tail} (Short: \p{Jg=YehWithTail}) (1)
+ \p{Joining_Group: Yudh} (Short: \p{Jg=Yudh}) (1)
+ \p{Joining_Group: Yudh_He} (Short: \p{Jg=YudhHe}) (1)
+ \p{Joining_Group: Zain} (Short: \p{Jg=Zain}) (1)
+ \p{Joining_Group: Zhain} (Short: \p{Jg=Zhain}) (1)
+ \p{Joining_Type: C} \p{Joining_Type=Join_Causing} (3)
+ \p{Joining_Type: D} \p{Joining_Type=Dual_Joining} (188)
+ \p{Joining_Type: Dual_Joining} (Short: \p{Jt=D}) (188)
+ \p{Joining_Type: Join_Causing} (Short: \p{Jt=C}) (3)
+ \p{Joining_Type: L} \p{Joining_Type=Left_Joining} (0)
+ \p{Joining_Type: Left_Joining} (Short: \p{Jt=L}) (0)
+ \p{Joining_Type: Non_Joining} (Short: \p{Jt=U}) (1_112_539)
+ \p{Joining_Type: R} \p{Joining_Type=Right_Joining} (74)
+ \p{Joining_Type: Right_Joining} (Short: \p{Jt=R}) (74)
+ \p{Joining_Type: T} \p{Joining_Type=Transparent} (1308)
+ \p{Joining_Type: Transparent} (Short: \p{Jt=T}) (1308)
+ \p{Joining_Type: U} \p{Joining_Type=Non_Joining} (1_112_539)
+ \p{Jt: *} \p{Joining_Type: *}
+ \p{Kaithi} \p{Script=Kaithi} (Short: \p{Kthi}; NOT
+ \p{Block=Kaithi}) (66)
+ \p{Kali} \p{Kayah_Li} (= \p{Script=Kayah_Li}) (48)
+ \p{Kana} \p{Katakana} (= \p{Script=Katakana}) (NOT
+ \p{Block=Katakana}) (299)
+ X \p{Kanbun} \p{Block=Kanbun} (16)
+ X \p{Kangxi_Radicals} \p{Block=Kangxi_Radicals} (224)
+ \p{Kannada} \p{Script=Kannada} (Short: \p{Knda}; NOT
+ \p{Block=Kannada}) (84)
+ \p{Katakana} \p{Script=Katakana} (Short: \p{Kana}; NOT
+ \p{Block=Katakana}) (299)
+ X \p{Katakana_Phonetic_Extensions} \p{Block=
+ Katakana_Phonetic_Extensions} (16)
+ \p{Kayah_Li} \p{Script=Kayah_Li} (Short: \p{Kali}) (48)
+ \p{Khar} \p{Kharoshthi} (= \p{Script=Kharoshthi})
+ (NOT \p{Block=Kharoshthi}) (65)
+ \p{Kharoshthi} \p{Script=Kharoshthi} (Short: \p{Khar};
+ NOT \p{Block=Kharoshthi}) (65)
+ \p{Khmer} \p{Script=Khmer} (Short: \p{Khmr}; NOT
+ \p{Block=Khmer}) (146)
+ X \p{Khmer_Symbols} \p{Block=Khmer_Symbols} (32)
+ \p{Khmr} \p{Khmer} (= \p{Script=Khmer}) (NOT
+ \p{Block=Khmer}) (146)
+ \p{Knda} \p{Kannada} (= \p{Script=Kannada}) (NOT
+ \p{Block=Kannada}) (84)
+ \p{Kthi} \p{Kaithi} (= \p{Script=Kaithi}) (NOT
+ \p{Block=Kaithi}) (66)
+ \p{L} \p{Letter} (= \p{General_Category=Letter})
+ (99_537)
+ \p{L&} \p{Cased_Letter} (= \p{General_Category=
+ Cased_Letter}) (3207)
+ \p{L_} \p{Cased_Letter} (= \p{General_Category=
+ Cased_Letter}) (3207)
+ \p{Lana} \p{Tai_Tham} (= \p{Script=Tai_Tham}) (NOT
+ \p{Block=Tai_Tham}) (127)
+ \p{Lao} \p{Script=Lao} (NOT \p{Block=Lao}) (65)
+ \p{Laoo} \p{Lao} (= \p{Script=Lao}) (NOT \p{Block=
+ Lao}) (65)
+ \p{Latin} \p{Script=Latin} (Short: \p{Latn}) (1244)
+ X \p{Latin_1} \p{Latin_1_Supplement} (= \p{Block=
+ Latin_1_Supplement}) (128)
+ X \p{Latin_1_Supplement} \p{Block=Latin_1_Supplement} (Short:
+ \p{InLatin1}) (128)
+ X \p{Latin_Extended_A} \p{Block=Latin_Extended_A} (128)
+ X \p{Latin_Extended_Additional} \p{Block=Latin_Extended_Additional}
+ (256)
+ X \p{Latin_Extended_B} \p{Block=Latin_Extended_B} (208)
+ X \p{Latin_Extended_C} \p{Block=Latin_Extended_C} (32)
+ X \p{Latin_Extended_D} \p{Block=Latin_Extended_D} (224)
+ \p{Latn} \p{Latin} (= \p{Script=Latin}) (1244)
+ \p{Lb: *} \p{Line_Break: *}
+ \p{LC} \p{Cased_Letter} (= \p{General_Category=
+ Cased_Letter}) (3207)
+ \p{Lepc} \p{Lepcha} (= \p{Script=Lepcha}) (NOT
+ \p{Block=Lepcha}) (74)
+ \p{Lepcha} \p{Script=Lepcha} (Short: \p{Lepc}; NOT
+ \p{Block=Lepcha}) (74)
+ \p{Letter} \p{General_Category=Letter} (Short: \p{L})
+ (99_537)
+ \p{Letter_Number} \p{General_Category=Letter_Number} (Short:
+ \p{Nl}) (224)
+ X \p{Letterlike_Symbols} \p{Block=Letterlike_Symbols} (80)
+ \p{Limb} \p{Limbu} (= \p{Script=Limbu}) (NOT
+ \p{Block=Limbu}) (66)
+ \p{Limbu} \p{Script=Limbu} (Short: \p{Limb}; NOT
+ \p{Block=Limbu}) (66)
+ \p{Linb} \p{Linear_B} (= \p{Script=Linear_B}) (211)
+ \p{Line_Break: AI} \p{Line_Break=Ambiguous} (644)
+ \p{Line_Break: AL} \p{Line_Break=Alphabetic} (14_092)
+ \p{Line_Break: Alphabetic} (Short: \p{Lb=AL}) (14_092)
+ \p{Line_Break: Ambiguous} (Short: \p{Lb=AI}) (644)
+ \p{Line_Break: B2} \p{Line_Break=Break_Both} (1)
+ \p{Line_Break: BA} \p{Line_Break=Break_After} (137)
+ \p{Line_Break: BB} \p{Line_Break=Break_Before} (19)
+ \p{Line_Break: BK} \p{Line_Break=Mandatory_Break} (4)
+ \p{Line_Break: Break_After} (Short: \p{Lb=BA}) (137)
+ \p{Line_Break: Break_Before} (Short: \p{Lb=BB}) (19)
+ \p{Line_Break: Break_Both} (Short: \p{Lb=B2}) (1)
+ \p{Line_Break: Break_Symbols} (Short: \p{Lb=SY}) (1)
+ \p{Line_Break: Carriage_Return} (Short: \p{Lb=CR}) (1)
+ \p{Line_Break: CB} \p{Line_Break=Contingent_Break} (1)
+ \p{Line_Break: CL} \p{Line_Break=Close_Punctuation} (87)
+ \p{Line_Break: Close_Parenthesis} (Short: \p{Lb=CP}) (2)
+ \p{Line_Break: Close_Punctuation} (Short: \p{Lb=CL}) (87)
+ \p{Line_Break: CM} \p{Line_Break=Combining_Mark} (1436)
+ \p{Line_Break: Combining_Mark} (Short: \p{Lb=CM}) (1436)
+ \p{Line_Break: Complex_Context} (Short: \p{Lb=SA}) (662)
+ \p{Line_Break: Contingent_Break} (Short: \p{Lb=CB}) (1)
+ \p{Line_Break: CP} \p{Line_Break=Close_Parenthesis} (2)
+ \p{Line_Break: CR} \p{Line_Break=Carriage_Return} (1)
+ \p{Line_Break: EX} \p{Line_Break=Exclamation} (34)
+ \p{Line_Break: Exclamation} (Short: \p{Lb=EX}) (34)
+ \p{Line_Break: GL} \p{Line_Break=Glue} (16)
+ \p{Line_Break: Glue} (Short: \p{Lb=GL}) (16)
+ \p{Line_Break: H2} (Short: \p{Lb=H2}) (399)
+ \p{Line_Break: H3} (Short: \p{Lb=H3}) (10_773)
+ \p{Line_Break: HY} \p{Line_Break=Hyphen} (1)
+ \p{Line_Break: Hyphen} (Short: \p{Lb=HY}) (1)
+ \p{Line_Break: ID} \p{Line_Break=Ideographic} (161_775)
+ \p{Line_Break: Ideographic} (Short: \p{Lb=ID}) (161_775)
+ \p{Line_Break: IN} \p{Line_Break=Inseparable} (4)
+ \p{Line_Break: Infix_Numeric} (Short: \p{Lb=IS}) (13)
+ \p{Line_Break: Inseparable} (Short: \p{Lb=IN}) (4)
+ \p{Line_Break: Inseperable} \p{Line_Break=Inseparable} (4)
+ \p{Line_Break: IS} \p{Line_Break=Infix_Numeric} (13)
+ \p{Line_Break: JL} (Short: \p{Lb=JL}) (125)
+ \p{Line_Break: JT} (Short: \p{Lb=JT}) (137)
+ \p{Line_Break: JV} (Short: \p{Lb=JV}) (95)
+ \p{Line_Break: LF} \p{Line_Break=Line_Feed} (1)
+ \p{Line_Break: Line_Feed} (Short: \p{Lb=LF}) (1)
+ \p{Line_Break: Mandatory_Break} (Short: \p{Lb=BK}) (4)
+ \p{Line_Break: Next_Line} (Short: \p{Lb=NL}) (1)
+ \p{Line_Break: NL} \p{Line_Break=Next_Line} (1)
+ \p{Line_Break: Nonstarter} (Short: \p{Lb=NS}) (77)
+ \p{Line_Break: NS} \p{Line_Break=Nonstarter} (77)
+ \p{Line_Break: NU} \p{Line_Break=Numeric} (403)
+ \p{Line_Break: Numeric} (Short: \p{Lb=NU}) (403)
+ \p{Line_Break: OP} \p{Line_Break=Open_Punctuation} (81)
+ \p{Line_Break: Open_Punctuation} (Short: \p{Lb=OP}) (81)
+ \p{Line_Break: PO} \p{Line_Break=Postfix_Numeric} (28)
+ \p{Line_Break: Postfix_Numeric} (Short: \p{Lb=PO}) (28)
+ \p{Line_Break: PR} \p{Line_Break=Prefix_Numeric} (43)
+ \p{Line_Break: Prefix_Numeric} (Short: \p{Lb=PR}) (43)
+ \p{Line_Break: QU} \p{Line_Break=Quotation} (34)
+ \p{Line_Break: Quotation} (Short: \p{Lb=QU}) (34)
+ \p{Line_Break: SA} \p{Line_Break=Complex_Context} (662)
+ D \p{Line_Break: SG} \p{Line_Break=Surrogate} (2048)
+ \p{Line_Break: SP} \p{Line_Break=Space} (1)
+ \p{Line_Break: Space} (Short: \p{Lb=SP}) (1)
+ D \p{Line_Break: Surrogate} Deprecated by Unicode because surrogates
+ should never appear in well-formed text,
+ and therefore shouldn't be the basis for
+ line breaking (Short: \p{Lb=SG}) (2048)
+ \p{Line_Break: SY} \p{Line_Break=Break_Symbols} (1)
+ \p{Line_Break: Unknown} (Short: \p{Lb=XX}) (920_933)
+ \p{Line_Break: WJ} \p{Line_Break=Word_Joiner} (2)
+ \p{Line_Break: Word_Joiner} (Short: \p{Lb=WJ}) (2)
+ \p{Line_Break: XX} \p{Line_Break=Unknown} (920_933)
+ \p{Line_Break: ZW} \p{Line_Break=ZWSpace} (1)
+ \p{Line_Break: ZWSpace} (Short: \p{Lb=ZW}) (1)
+ \p{Line_Separator} \p{General_Category=Line_Separator}
+ (Short: \p{Zl}) (1)
+ \p{Linear_B} \p{Script=Linear_B} (Short: \p{Linb}) (211)
+ X \p{Linear_B_Ideograms} \p{Block=Linear_B_Ideograms} (128)
+ X \p{Linear_B_Syllabary} \p{Block=Linear_B_Syllabary} (128)
+ \p{Lisu} \p{Script=Lisu} (48)
+ \p{Ll} \p{Lowercase_Letter} (=
+ \p{General_Category=Lowercase_Letter})
+ (1749)
+ \p{Lm} \p{Modifier_Letter} (=
+ \p{General_Category=Modifier_Letter})
+ (202)
+ \p{Lo} \p{Other_Letter} (= \p{General_Category=
+ Other_Letter}) (96_128)
+ \p{LOE} \p{Logical_Order_Exception} (=
+ \p{Logical_Order_Exception=Y}) (15)
+ \p{LOE: *} \p{Logical_Order_Exception: *}
+ \p{Logical_Order_Exception} \p{Logical_Order_Exception=Y} (Short:
+ \p{LOE}) (15)
+ \p{Logical_Order_Exception: N*} (Short: \p{LOE=N}, \P{LOE})
+ (1_114_097)
+ \p{Logical_Order_Exception: Y*} (Short: \p{LOE=Y}, \p{LOE}) (15)
+ X \p{Low_Surrogates} \p{Block=Low_Surrogates} (1024)
+ \p{Lower} \p{Lowercase=Y} (1908)
+ \p{Lower: *} \p{Lowercase: *}
+ \p{Lowercase} \p{Lower} (= \p{Lowercase=Y}) (1908)
+ \p{Lowercase: N*} (Short: \p{Lower=N}, \P{Lower}) (1_112_204)
+ \p{Lowercase: Y*} (Short: \p{Lower=Y}, \p{Lower}) (1908)
+ \p{Lowercase_Letter} \p{General_Category=Lowercase_Letter}
+ (Short: \p{Ll}) (1749)
+ \p{Lt} \p{Title} (= \p{General_Category=
+ Titlecase_Letter}) (31)
+ \p{Lu} \p{Uppercase_Letter} (=
+ \p{General_Category=Uppercase_Letter})
+ (1427)
+ \p{Lyci} \p{Lycian} (= \p{Script=Lycian}) (NOT
+ \p{Block=Lycian}) (29)
+ \p{Lycian} \p{Script=Lycian} (Short: \p{Lyci}; NOT
+ \p{Block=Lycian}) (29)
+ \p{Lydi} \p{Lydian} (= \p{Script=Lydian}) (NOT
+ \p{Block=Lydian}) (27)
+ \p{Lydian} \p{Script=Lydian} (Short: \p{Lydi}; NOT
+ \p{Block=Lydian}) (27)
+ \p{M} \p{Mark} (= \p{General_Category=Mark})
+ (1451)
+ X \p{Mahjong_Tiles} \p{Block=Mahjong_Tiles} (48)
+ \p{Malayalam} \p{Script=Malayalam} (Short: \p{Mlym}; NOT
+ \p{Block=Malayalam}) (95)
+ \p{Mark} \p{General_Category=Mark} (Short: \p{M})
+ (1451)
+ \p{Math} \p{Math=Y} (2161)
+ \p{Math: N*} (Single: \P{Math}) (1_111_951)
+ \p{Math: Y*} (Single: \p{Math}) (2161)
+ \p{Math_Symbol} \p{General_Category=Math_Symbol} (Short:
+ \p{Sm}) (945)
+ X \p{Mathematical_Alphanumeric_Symbols} \p{Block=
+ Mathematical_Alphanumeric_Symbols} (1024)
+ X \p{Mathematical_Operators} \p{Block=Mathematical_Operators} (256)
+ \p{Mc} \p{Spacing_Mark} (= \p{General_Category=
+ Spacing_Mark}) (276)
+ \p{Me} \p{Enclosing_Mark} (= \p{General_Category=
+ Enclosing_Mark}) (13)
+ \p{Meetei_Mayek} \p{Script=Meetei_Mayek} (Short: \p{Mtei};
+ NOT \p{Block=Meetei_Mayek}) (56)
+ X \p{Miscellaneous_Mathematical_Symbols_A} \p{Block=
+ Miscellaneous_Mathematical_Symbols_A}
+ (48)
+ X \p{Miscellaneous_Mathematical_Symbols_B} \p{Block=
+ Miscellaneous_Mathematical_Symbols_B}
+ (128)
+ X \p{Miscellaneous_Symbols} \p{Block=Miscellaneous_Symbols} (256)
+ X \p{Miscellaneous_Symbols_And_Arrows} \p{Block=
+ Miscellaneous_Symbols_And_Arrows} (256)
+ X \p{Miscellaneous_Technical} \p{Block=Miscellaneous_Technical} (256)
+ \p{Mlym} \p{Malayalam} (= \p{Script=Malayalam})
+ (NOT \p{Block=Malayalam}) (95)
+ \p{Mn} \p{Nonspacing_Mark} (=
+ \p{General_Category=Nonspacing_Mark})
+ (1162)
+ \p{Modifier_Letter} \p{General_Category=Modifier_Letter}
+ (Short: \p{Lm}) (202)
+ \p{Modifier_Symbol} \p{General_Category=Modifier_Symbol}
+ (Short: \p{Sk}) (99)
+ X \p{Modifier_Tone_Letters} \p{Block=Modifier_Tone_Letters} (32)
+ \p{Mong} \p{Mongolian} (= \p{Script=Mongolian})
+ (NOT \p{Block=Mongolian}) (153)
+ \p{Mongolian} \p{Script=Mongolian} (Short: \p{Mong}; NOT
+ \p{Block=Mongolian}) (153)
+ \p{Mtei} \p{Meetei_Mayek} (= \p{Script=
+ Meetei_Mayek}) (NOT \p{Block=
+ Meetei_Mayek}) (56)
+ X \p{Musical_Symbols} \p{Block=Musical_Symbols} (256)
+ \p{Myanmar} \p{Script=Myanmar} (Short: \p{Mymr}; NOT
+ \p{Block=Myanmar}) (188)
+ X \p{Myanmar_Extended_A} \p{Block=Myanmar_Extended_A} (32)
+ \p{Mymr} \p{Myanmar} (= \p{Script=Myanmar}) (NOT
+ \p{Block=Myanmar}) (188)
+ \p{N} \p{Number} (= \p{General_Category=Number})
+ (1064)
+ \p{NChar} \p{Noncharacter_Code_Point} (=
+ \p{Noncharacter_Code_Point=Y}) (66)
+ \p{NChar: *} \p{Noncharacter_Code_Point: *}
+ \p{Nd} \p{Digit} (= \p{General_Category=
+ Decimal_Number}) (411)
+ \p{New_Tai_Lue} \p{Script=New_Tai_Lue} (Short: \p{Talu};
+ NOT \p{Block=New_Tai_Lue}) (83)
+ \p{NFC_QC: *} \p{NFC_Quick_Check: *}
+ \p{NFC_Quick_Check: M} \p{NFC_Quick_Check=Maybe} (103)
+ \p{NFC_Quick_Check: Maybe} (Short: \p{NFCQC=M}) (103)
+ \p{NFC_Quick_Check: N} \p{NFC_Quick_Check=No} (NOT
+ \P{NFC_Quick_Check} NOR \P{NFC_QC} NOR
+ \P{Is_NFC_Quick_Check} NOR
+ \P{Is_NFC_QC}) (1118)
+ \p{NFC_Quick_Check: No} (Short: \p{NFCQC=N}; NOT
+ \P{NFC_Quick_Check} NOR \P{NFC_QC} NOR
+ \P{Is_NFC_Quick_Check} NOR
+ \P{Is_NFC_QC}) (1118)
+ \p{NFC_Quick_Check: Y} \p{NFC_Quick_Check=Yes} (NOT
+ \p{NFC_Quick_Check} NOR \p{NFC_QC} NOR
+ \p{Is_NFC_Quick_Check} NOR
+ \p{Is_NFC_QC}) (1_112_891)
+ \p{NFC_Quick_Check: Yes} (Short: \p{NFCQC=Y}; NOT
+ \p{NFC_Quick_Check} NOR \p{NFC_QC} NOR
+ \p{Is_NFC_Quick_Check} NOR
+ \p{Is_NFC_QC}) (1_112_891)
+ \p{NFD_QC: *} \p{NFD_Quick_Check: *}
+ \p{NFD_Quick_Check: N} \p{NFD_Quick_Check=No} (NOT
+ \P{NFD_Quick_Check} NOR \P{NFD_QC} NOR
+ \P{Is_NFD_Quick_Check} NOR
+ \P{Is_NFD_QC}) (13_221)
+ \p{NFD_Quick_Check: No} (Short: \p{NFDQC=N}; NOT
+ \P{NFD_Quick_Check} NOR \P{NFD_QC} NOR
+ \P{Is_NFD_Quick_Check} NOR
+ \P{Is_NFD_QC}) (13_221)
+ \p{NFD_Quick_Check: Y} \p{NFD_Quick_Check=Yes} (NOT
+ \p{NFD_Quick_Check} NOR \p{NFD_QC} NOR
+ \p{Is_NFD_Quick_Check} NOR
+ \p{Is_NFD_QC}) (1_100_891)
+ \p{NFD_Quick_Check: Yes} (Short: \p{NFDQC=Y}; NOT
+ \p{NFD_Quick_Check} NOR \p{NFD_QC} NOR
+ \p{Is_NFD_Quick_Check} NOR
+ \p{Is_NFD_QC}) (1_100_891)
+ \p{NFKC_QC: *} \p{NFKC_Quick_Check: *}
+ \p{NFKC_Quick_Check: M} \p{NFKC_Quick_Check=Maybe} (103)
+ \p{NFKC_Quick_Check: Maybe} (Short: \p{NFKCQC=M}) (103)
+ \p{NFKC_Quick_Check: N} \p{NFKC_Quick_Check=No} (NOT
+ \P{NFKC_Quick_Check} NOR \P{NFKC_QC} NOR
+ \P{Is_NFKC_Quick_Check} NOR
+ \P{Is_NFKC_QC}) (4597)
+ \p{NFKC_Quick_Check: No} (Short: \p{NFKCQC=N}; NOT
+ \P{NFKC_Quick_Check} NOR \P{NFKC_QC} NOR
+ \P{Is_NFKC_Quick_Check} NOR
+ \P{Is_NFKC_QC}) (4597)
+ \p{NFKC_Quick_Check: Y} \p{NFKC_Quick_Check=Yes} (NOT
+ \p{NFKC_Quick_Check} NOR \p{NFKC_QC} NOR
+ \p{Is_NFKC_Quick_Check} NOR
+ \p{Is_NFKC_QC}) (1_109_412)
+ \p{NFKC_Quick_Check: Yes} (Short: \p{NFKCQC=Y}; NOT
+ \p{NFKC_Quick_Check} NOR \p{NFKC_QC} NOR
+ \p{Is_NFKC_Quick_Check} NOR
+ \p{Is_NFKC_QC}) (1_109_412)
+ \p{NFKD_QC: *} \p{NFKD_Quick_Check: *}
+ \p{NFKD_Quick_Check: N} \p{NFKD_Quick_Check=No} (NOT
+ \P{NFKD_Quick_Check} NOR \P{NFKD_QC} NOR
+ \P{Is_NFKD_Quick_Check} NOR
+ \P{Is_NFKD_QC}) (16_688)
+ \p{NFKD_Quick_Check: No} (Short: \p{NFKDQC=N}; NOT
+ \P{NFKD_Quick_Check} NOR \P{NFKD_QC} NOR
+ \P{Is_NFKD_Quick_Check} NOR
+ \P{Is_NFKD_QC}) (16_688)
+ \p{NFKD_Quick_Check: Y} \p{NFKD_Quick_Check=Yes} (NOT
+ \p{NFKD_Quick_Check} NOR \p{NFKD_QC} NOR
+ \p{Is_NFKD_Quick_Check} NOR
+ \p{Is_NFKD_QC}) (1_097_424)
+ \p{NFKD_Quick_Check: Yes} (Short: \p{NFKDQC=Y}; NOT
+ \p{NFKD_Quick_Check} NOR \p{NFKD_QC} NOR
+ \p{Is_NFKD_Quick_Check} NOR
+ \p{Is_NFKD_QC}) (1_097_424)
+ \p{Nko} \p{Script=Nko} (NOT \p{NKo}) (59)
+ \p{Nkoo} \p{Nko} (= \p{Script=Nko}) (NOT \p{NKo})
+ (59)
+ \p{Nl} \p{Letter_Number} (= \p{General_Category=
+ Letter_Number}) (224)
+ \p{No} \p{Other_Number} (= \p{General_Category=
+ Other_Number}) (429)
+ X \p{No_Block} \p{Block=No_Block} (864_192)
+ \p{Noncharacter_Code_Point} \p{Noncharacter_Code_Point=Y} (Short:
+ \p{NChar}) (66)
+ \p{Noncharacter_Code_Point: N*} (Short: \p{NChar=N}, \P{NChar})
+ (1_114_046)
+ \p{Noncharacter_Code_Point: Y*} (Short: \p{NChar=Y}, \p{NChar})
+ (66)
+ \p{Nonspacing_Mark} \p{General_Category=Nonspacing_Mark}
+ (Short: \p{Mn}) (1162)
+ \p{Nt: *} \p{Numeric_Type: *}
+ \p{Number} \p{General_Category=Number} (Short: \p{N})
+ (1064)
+ X \p{Number_Forms} \p{Block=Number_Forms} (64)
+ \p{Numeric_Type: De} \p{Numeric_Type=Decimal} (411)
+ \p{Numeric_Type: Decimal} (Short: \p{Nt=De}) (411)
+ \p{Numeric_Type: Di} \p{Numeric_Type=Digit} (118)
+ \p{Numeric_Type: Digit} (Short: \p{Nt=Di}) (118)
+ \p{Numeric_Type: None} (Short: \p{Nt=None}) (1_112_971)
+ \p{Numeric_Type: Nu} \p{Numeric_Type=Numeric} (612)
+ \p{Numeric_Type: Numeric} (Short: \p{Nt=Nu}) (612)
+ T \p{Numeric_Value: -1/2} (Short: \p{Nv=-1/2}) (1)
+ T \p{Numeric_Value: 0} (Short: \p{Nv=0}) (55)
+ T \p{Numeric_Value: 1/16} (Short: \p{Nv=1/16}) (2)
+ T \p{Numeric_Value: 1/10} (Short: \p{Nv=1/10}) (1)
+ T \p{Numeric_Value: 1/9} (Short: \p{Nv=1/9}) (1)
+ T \p{Numeric_Value: 1/8} (Short: \p{Nv=1/8}) (4)
+ T \p{Numeric_Value: 1/7} (Short: \p{Nv=1/7}) (1)
+ T \p{Numeric_Value: 1/6} (Short: \p{Nv=1/6}) (2)
+ T \p{Numeric_Value: 3/16} (Short: \p{Nv=3/16}) (2)
+ T \p{Numeric_Value: 1/5} (Short: \p{Nv=1/5}) (1)
+ T \p{Numeric_Value: 1/4} (Short: \p{Nv=1/4}) (8)
+ T \p{Numeric_Value: 1/3} (Short: \p{Nv=1/3}) (4)
+ T \p{Numeric_Value: 3/8} (Short: \p{Nv=3/8}) (1)
+ T \p{Numeric_Value: 2/5} (Short: \p{Nv=2/5}) (1)
+ T \p{Numeric_Value: 1/2} (Short: \p{Nv=1/2}) (9)
+ T \p{Numeric_Value: 3/5} (Short: \p{Nv=3/5}) (1)
+ T \p{Numeric_Value: 5/8} (Short: \p{Nv=5/8}) (1)
+ T \p{Numeric_Value: 2/3} (Short: \p{Nv=2/3}) (5)
+ T \p{Numeric_Value: 3/4} (Short: \p{Nv=3/4}) (5)
+ T \p{Numeric_Value: 4/5} (Short: \p{Nv=4/5}) (1)
+ T \p{Numeric_Value: 5/6} (Short: \p{Nv=5/6}) (2)
+ T \p{Numeric_Value: 7/8} (Short: \p{Nv=7/8}) (1)
+ T \p{Numeric_Value: 1} (Short: \p{Nv=1}) (91)
+ T \p{Numeric_Value: 3/2} (Short: \p{Nv=3/2}) (1)
+ T \p{Numeric_Value: 2} (Short: \p{Nv=2}) (94)
+ T \p{Numeric_Value: 5/2} (Short: \p{Nv=5/2}) (1)
+ T \p{Numeric_Value: 3} (Short: \p{Nv=3}) (96)
+ T \p{Numeric_Value: 7/2} (Short: \p{Nv=7/2}) (1)
+ T \p{Numeric_Value: 4} (Short: \p{Nv=4}) (87)
+ T \p{Numeric_Value: 9/2} (Short: \p{Nv=9/2}) (1)
+ T \p{Numeric_Value: 5} (Short: \p{Nv=5}) (84)
+ T \p{Numeric_Value: 11/2} (Short: \p{Nv=11/2}) (1)
+ T \p{Numeric_Value: 6} (Short: \p{Nv=6}) (76)
+ T \p{Numeric_Value: 13/2} (Short: \p{Nv=13/2}) (1)
+ T \p{Numeric_Value: 7} (Short: \p{Nv=7}) (75)
+ T \p{Numeric_Value: 15/2} (Short: \p{Nv=15/2}) (1)
+ T \p{Numeric_Value: 8} (Short: \p{Nv=8}) (71)
+ T \p{Numeric_Value: 17/2} (Short: \p{Nv=17/2}) (1)
+ T \p{Numeric_Value: 9} (Short: \p{Nv=9}) (75)
+ T \p{Numeric_Value: 10} (Short: \p{Nv=10}) (38)
+ T \p{Numeric_Value: 11} (Short: \p{Nv=11}) (6)
+ T \p{Numeric_Value: 12} (Short: \p{Nv=12}) (6)
+ T \p{Numeric_Value: 13} (Short: \p{Nv=13}) (4)
+ T \p{Numeric_Value: 14} (Short: \p{Nv=14}) (4)
+ T \p{Numeric_Value: 15} (Short: \p{Nv=15}) (4)
+ T \p{Numeric_Value: 16} (Short: \p{Nv=16}) (5)
+ T \p{Numeric_Value: 17} (Short: \p{Nv=17}) (5)
+ T \p{Numeric_Value: 18} (Short: \p{Nv=18}) (5)
+ T \p{Numeric_Value: 19} (Short: \p{Nv=19}) (5)
+ T \p{Numeric_Value: 20} (Short: \p{Nv=20}) (17)
+ T \p{Numeric_Value: 21} (Short: \p{Nv=21}) (1)
+ T \p{Numeric_Value: 22} (Short: \p{Nv=22}) (1)
+ T \p{Numeric_Value: 23} (Short: \p{Nv=23}) (1)
+ T \p{Numeric_Value: 24} (Short: \p{Nv=24}) (1)
+ T \p{Numeric_Value: 25} (Short: \p{Nv=25}) (1)
+ T \p{Numeric_Value: 26} (Short: \p{Nv=26}) (1)
+ T \p{Numeric_Value: 27} (Short: \p{Nv=27}) (1)
+ T \p{Numeric_Value: 28} (Short: \p{Nv=28}) (1)
+ T \p{Numeric_Value: 29} (Short: \p{Nv=29}) (1)
+ T \p{Numeric_Value: 30} (Short: \p{Nv=30}) (9)
+ T \p{Numeric_Value: 31} (Short: \p{Nv=31}) (1)
+ T \p{Numeric_Value: 32} (Short: \p{Nv=32}) (1)
+ T \p{Numeric_Value: 33} (Short: \p{Nv=33}) (1)
+ T \p{Numeric_Value: 34} (Short: \p{Nv=34}) (1)
+ T \p{Numeric_Value: 35} (Short: \p{Nv=35}) (1)
+ T \p{Numeric_Value: 36} (Short: \p{Nv=36}) (1)
+ T \p{Numeric_Value: 37} (Short: \p{Nv=37}) (1)
+ T \p{Numeric_Value: 38} (Short: \p{Nv=38}) (1)
+ T \p{Numeric_Value: 39} (Short: \p{Nv=39}) (1)
+ T \p{Numeric_Value: 40} (Short: \p{Nv=40}) (8)
+ T \p{Numeric_Value: 41} (Short: \p{Nv=41}) (1)
+ T \p{Numeric_Value: 42} (Short: \p{Nv=42}) (1)
+ T \p{Numeric_Value: 43} (Short: \p{Nv=43}) (1)
+ T \p{Numeric_Value: 44} (Short: \p{Nv=44}) (1)
+ T \p{Numeric_Value: 45} (Short: \p{Nv=45}) (1)
+ T \p{Numeric_Value: 46} (Short: \p{Nv=46}) (1)
+ T \p{Numeric_Value: 47} (Short: \p{Nv=47}) (1)
+ T \p{Numeric_Value: 48} (Short: \p{Nv=48}) (1)
+ T \p{Numeric_Value: 49} (Short: \p{Nv=49}) (1)
+ T \p{Numeric_Value: 50} (Short: \p{Nv=50}) (18)
+ T \p{Numeric_Value: 60} (Short: \p{Nv=60}) (4)
+ T \p{Numeric_Value: 70} (Short: \p{Nv=70}) (4)
+ T \p{Numeric_Value: 80} (Short: \p{Nv=80}) (4)
+ T \p{Numeric_Value: 90} (Short: \p{Nv=90}) (5)
+ T \p{Numeric_Value: 100} (Short: \p{Nv=100}) (19)
+ T \p{Numeric_Value: 200} (Short: \p{Nv=200}) (2)
+ T \p{Numeric_Value: 300} (Short: \p{Nv=300}) (3)
+ T \p{Numeric_Value: 400} (Short: \p{Nv=400}) (2)
+ T \p{Numeric_Value: 500} (Short: \p{Nv=500}) (12)
+ T \p{Numeric_Value: 600} (Short: \p{Nv=600}) (2)
+ T \p{Numeric_Value: 700} (Short: \p{Nv=700}) (2)
+ T \p{Numeric_Value: 800} (Short: \p{Nv=800}) (2)
+ T \p{Numeric_Value: 900} (Short: \p{Nv=900}) (3)
+ T \p{Numeric_Value: 1000} (Short: \p{Nv=1000}) (16)
+ T \p{Numeric_Value: 2000} (Short: \p{Nv=2000}) (1)
+ T \p{Numeric_Value: 3000} (Short: \p{Nv=3000}) (1)
+ T \p{Numeric_Value: 4000} (Short: \p{Nv=4000}) (1)
+ T \p{Numeric_Value: 5000} (Short: \p{Nv=5000}) (5)
+ T \p{Numeric_Value: 6000} (Short: \p{Nv=6000}) (1)
+ T \p{Numeric_Value: 7000} (Short: \p{Nv=7000}) (1)
+ T \p{Numeric_Value: 8000} (Short: \p{Nv=8000}) (1)
+ T \p{Numeric_Value: 9000} (Short: \p{Nv=9000}) (1)
+ T \p{Numeric_Value: 10000} (= 1.0e+004) (Short: \p{Nv=10000}) (7)
+ T \p{Numeric_Value: 20000} (= 2.0e+004) (Short: \p{Nv=20000}) (1)
+ T \p{Numeric_Value: 30000} (= 3.0e+004) (Short: \p{Nv=30000}) (1)
+ T \p{Numeric_Value: 40000} (= 4.0e+004) (Short: \p{Nv=40000}) (1)
+ T \p{Numeric_Value: 50000} (= 5.0e+004) (Short: \p{Nv=50000}) (4)
+ T \p{Numeric_Value: 60000} (= 6.0e+004) (Short: \p{Nv=60000}) (1)
+ T \p{Numeric_Value: 70000} (= 7.0e+004) (Short: \p{Nv=70000}) (1)
+ T \p{Numeric_Value: 80000} (= 8.0e+004) (Short: \p{Nv=80000}) (1)
+ T \p{Numeric_Value: 90000} (= 9.0e+004) (Short: \p{Nv=90000}) (1)
+ T \p{Numeric_Value: 100000} (= 1.0e+005) (Short: \p{Nv=100000}) (1)
+ T \p{Numeric_Value: 100000000} (= 1.0e+008) (Short: \p{Nv=
+ 100000000}) (2)
+ T \p{Numeric_Value: 1000000000000} (= 1.0e+012) (Short: \p{Nv=
+ 1000000000000}) (1)
+ \p{Numeric_Value: NaN} (Short: \p{Nv=NaN}) (1_112_971)
+ \p{Nv: *} \p{Numeric_Value: *}
+ D \p{OAlpha} \p{Other_Alphabetic} (=
+ \p{Other_Alphabetic=Y}) (759)
+ D \p{OAlpha: *} \p{Other_Alphabetic: *}
+ D \p{ODI} \p{Other_Default_Ignorable_Code_Point} (=
+ \p{Other_Default_Ignorable_Code_Point=
+ Y}) (3778)
+ D \p{ODI: *} \p{Other_Default_Ignorable_Code_Point: *}
+ \p{Ogam} \p{Ogham} (= \p{Script=Ogham}) (NOT
+ \p{Block=Ogham}) (29)
+ \p{Ogham} \p{Script=Ogham} (Short: \p{Ogam}; NOT
+ \p{Block=Ogham}) (29)
+ D \p{OGr_Ext} \p{Other_Grapheme_Extend} (=
+ \p{Other_Grapheme_Extend=Y}) (23)
+ D \p{OGr_Ext: *} \p{Other_Grapheme_Extend: *}
+ D \p{OIDC} \p{Other_ID_Continue} (=
+ \p{Other_ID_Continue=Y}) (11)
+ D \p{OIDC: *} \p{Other_ID_Continue: *}
+ D \p{OIDS} \p{Other_ID_Start} (= \p{Other_ID_Start=
+ Y}) (4)
+ D \p{OIDS: *} \p{Other_ID_Start: *}
+ \p{Ol_Chiki} \p{Script=Ol_Chiki} (Short: \p{Olck}) (48)
+ \p{Olck} \p{Ol_Chiki} (= \p{Script=Ol_Chiki}) (48)
+ \p{Old_Italic} \p{Script=Old_Italic} (Short: \p{Ital};
+ NOT \p{Block=Old_Italic}) (35)
+ \p{Old_Persian} \p{Script=Old_Persian} (Short: \p{Xpeo};
+ NOT \p{Block=Old_Persian}) (50)
+ \p{Old_South_Arabian} \p{Script=Old_South_Arabian} (Short:
+ \p{Sarb}) (32)
+ \p{Old_Turkic} \p{Script=Old_Turkic} (Short: \p{Orkh};
+ NOT \p{Block=Old_Turkic}) (73)
+ D \p{OLower} \p{Other_Lowercase} (= \p{Other_Lowercase=
+ Y}) (159)
+ D \p{OLower: *} \p{Other_Lowercase: *}
+ D \p{OMath} \p{Other_Math} (= \p{Other_Math=Y}) (1216)
+ D \p{OMath: *} \p{Other_Math: *}
+ \p{Open_Punctuation} \p{General_Category=Open_Punctuation}
+ (Short: \p{Ps}) (72)
+ X \p{Optical_Character_Recognition} \p{Block=
+ Optical_Character_Recognition} (32)
+ \p{Oriya} \p{Script=Oriya} (Short: \p{Orya}; NOT
+ \p{Block=Oriya}) (84)
+ \p{Orkh} \p{Old_Turkic} (= \p{Script=Old_Turkic})
+ (NOT \p{Block=Old_Turkic}) (73)
+ \p{Orya} \p{Oriya} (= \p{Script=Oriya}) (NOT
+ \p{Block=Oriya}) (84)
+ \p{Osma} \p{Osmanya} (= \p{Script=Osmanya}) (NOT
+ \p{Block=Osmanya}) (40)
+ \p{Osmanya} \p{Script=Osmanya} (Short: \p{Osma}; NOT
+ \p{Block=Osmanya}) (40)
+ \p{Other} \p{General_Category=Other} (Short: \p{C})
+ (1_006_956)
+ D \p{Other_Alphabetic} \p{Other_Alphabetic=Y} (Short: \p{OAlpha})
+ (759)
+ D \p{Other_Alphabetic: N*} Used by Unicode internally for generating
+ the Alphabetic property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OAlpha=N},
+ \P{OAlpha}) (1_113_353)
+ D \p{Other_Alphabetic: Y*} Used by Unicode internally for generating
+ the Alphabetic property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OAlpha=Y},
+ \p{OAlpha}) (759)
+ D \p{Other_Default_Ignorable_Code_Point}
+ \p{Other_Default_Ignorable_Code_Point=Y}
+ (Short: \p{ODI}) (3778)
+ D \p{Other_Default_Ignorable_Code_Point: N*} Used by Unicode
+ internally for generating the
+ Default_Ignorable_Code_Point property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{ODI=N}, \P{ODI}) (1_110_334)
+ D \p{Other_Default_Ignorable_Code_Point: Y*} Used by Unicode
+ internally for generating the
+ Default_Ignorable_Code_Point property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{ODI=Y}, \p{ODI}) (3778)
+ D \p{Other_Grapheme_Extend} \p{Other_Grapheme_Extend=Y} (Short:
+ \p{OGrExt}) (23)
+ D \p{Other_Grapheme_Extend: N*} Used by Unicode internally for
+ generating the Grapheme_Extend property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{OGrExt=N}, \P{OGrExt}) (1_114_089)
+ D \p{Other_Grapheme_Extend: Y*} Used by Unicode internally for
+ generating the Grapheme_Extend property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{OGrExt=Y}, \p{OGrExt}) (23)
+ D \p{Other_ID_Continue} \p{Other_ID_Continue=Y} (Short: \p{OIDC})
+ (11)
+ D \p{Other_ID_Continue: N*} Used by Unicode internally for
+ generating the ID_Continue property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{OIDC=N}, \P{OIDC}) (1_114_101)
+ D \p{Other_ID_Continue: Y*} Used by Unicode internally for
+ generating the ID_Continue property
+ (which should be used instead) and not
+ intended to be used stand-alone (Short:
+ \p{OIDC=Y}, \p{OIDC}) (11)
+ D \p{Other_ID_Start} \p{Other_ID_Start=Y} (Short: \p{OIDS}) (4)
+ D \p{Other_ID_Start: N*} Used by Unicode internally for generating
+ the ID_Start property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OIDS=N},
+ \P{OIDS}) (1_114_108)
+ D \p{Other_ID_Start: Y*} Used by Unicode internally for generating
+ the ID_Start property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OIDS=Y},
+ \p{OIDS}) (4)
+ \p{Other_Letter} \p{General_Category=Other_Letter} (Short:
+ \p{Lo}) (96_128)
+ D \p{Other_Lowercase} \p{Other_Lowercase=Y} (Short: \p{OLower})
+ (159)
+ D \p{Other_Lowercase: N*} Used by Unicode internally for generating
+ the Lowercase property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OLower=N},
+ \P{OLower}) (1_113_953)
+ D \p{Other_Lowercase: Y*} Used by Unicode internally for generating
+ the Lowercase property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OLower=Y},
+ \p{OLower}) (159)
+ D \p{Other_Math} \p{Other_Math=Y} (Short: \p{OMath}) (1216)
+ D \p{Other_Math: N*} Used by Unicode internally for generating
+ the Math property (which should be used
+ instead) and not intended to be used
+ stand-alone (Short: \p{OMath=N},
+ \P{OMath}) (1_112_896)
+ D \p{Other_Math: Y*} Used by Unicode internally for generating
+ the Math property (which should be used
+ instead) and not intended to be used
+ stand-alone (Short: \p{OMath=Y},
+ \p{OMath}) (1216)
+ \p{Other_Number} \p{General_Category=Other_Number} (Short:
+ \p{No}) (429)
+ \p{Other_Punctuation} \p{General_Category=Other_Punctuation}
+ (Short: \p{Po}) (389)
+ \p{Other_Symbol} \p{General_Category=Other_Symbol} (Short:
+ \p{So}) (3409)
+ D \p{Other_Uppercase} \p{Other_Uppercase=Y} (Short: \p{OUpper})
+ (42)
+ D \p{Other_Uppercase: N*} Used by Unicode internally for generating
+ the Uppercase property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OUpper=N},
+ \P{OUpper}) (1_114_070)
+ D \p{Other_Uppercase: Y*} Used by Unicode internally for generating
+ the Uppercase property (which should be
+ used instead) and not intended to be
+ used stand-alone (Short: \p{OUpper=Y},
+ \p{OUpper}) (42)
+ D \p{OUpper} \p{Other_Uppercase} (= \p{Other_Uppercase=
+ Y}) (42)
+ D \p{OUpper: *} \p{Other_Uppercase: *}
+ \p{P} \p{Punct} (= \p{General_Category=
+ Punctuation}) (585)
+ \p{Paragraph_Separator} \p{General_Category=Paragraph_Separator}
+ (Short: \p{Zp}) (1)
+ \p{Pat_Syn} \p{Pattern_Syntax} (= \p{Pattern_Syntax=
+ Y}) (2760)
+ \p{Pat_Syn: *} \p{Pattern_Syntax: *}
+ \p{Pat_WS} \p{Pattern_White_Space} (=
+ \p{Pattern_White_Space=Y}) (11)
+ \p{Pat_WS: *} \p{Pattern_White_Space: *}
+ \p{Pattern_Syntax} \p{Pattern_Syntax=Y} (Short: \p{PatSyn})
+ (2760)
+ \p{Pattern_Syntax: N*} (Short: \p{PatSyn=N}, \P{PatSyn})
+ (1_111_352)
+ \p{Pattern_Syntax: Y*} (Short: \p{PatSyn=Y}, \p{PatSyn}) (2760)
+ \p{Pattern_White_Space} \p{Pattern_White_Space=Y} (Short:
+ \p{PatWS}) (11)
+ \p{Pattern_White_Space: N*} (Short: \p{PatWS=N}, \P{PatWS})
+ (1_114_101)
+ \p{Pattern_White_Space: Y*} (Short: \p{PatWS=Y}, \p{PatWS}) (11)
+ \p{Pc} \p{Connector_Punctuation} (=
+ \p{General_Category=
+ Connector_Punctuation}) (10)
+ \p{Pd} \p{Dash_Punctuation} (=
+ \p{General_Category=Dash_Punctuation})
+ (21)
+ \p{Pe} \p{Close_Punctuation} (=
+ \p{General_Category=Close_Punctuation})
+ (71)
+ \p{PerlSpace} \s, restricted to ASCII (5)
+ \p{PerlWord} \w, restricted to ASCII = [A-Za-z0-9_] (63)
+ \p{Pf} \p{Final_Punctuation} (=
+ \p{General_Category=Final_Punctuation})
+ (10)
+ \p{Phag} \p{Phags_Pa} (= \p{Script=Phags_Pa}) (NOT
+ \p{Block=Phags_Pa}) (56)
+ \p{Phags_Pa} \p{Script=Phags_Pa} (Short: \p{Phag}; NOT
+ \p{Block=Phags_Pa}) (56)
+ X \p{Phaistos_Disc} \p{Block=Phaistos_Disc} (48)
+ \p{Phli} \p{Inscriptional_Pahlavi} (= \p{Script=
+ Inscriptional_Pahlavi}) (NOT \p{Block=
+ Inscriptional_Pahlavi}) (27)
+ \p{Phnx} \p{Phoenician} (= \p{Script=Phoenician})
+ (NOT \p{Block=Phoenician}) (29)
+ \p{Phoenician} \p{Script=Phoenician} (Short: \p{Phnx};
+ NOT \p{Block=Phoenician}) (29)
+ X \p{Phonetic_Extensions} \p{Block=Phonetic_Extensions} (128)
+ X \p{Phonetic_Extensions_Supplement} \p{Block=
+ Phonetic_Extensions_Supplement} (64)
+ \p{Pi} \p{Initial_Punctuation} (=
+ \p{General_Category=
+ Initial_Punctuation}) (12)
+ \p{Po} \p{Other_Punctuation} (=
+ \p{General_Category=Other_Punctuation})
+ (389)
+ \p{PosixAlnum} [A-Za-z0-9] (62)
+ \p{PosixAlpha} [A-Za-z] (52)
+ \p{PosixBlank} \t and ' ' (2)
+ \p{PosixCntrl} [\x00-\x1F] (33)
+ \p{PosixDigit} [0-9] (10)
+ \p{PosixGraph} [\x21-\x7E] (94)
+ \p{PosixLower} [a-z] (26)
+ \p{PosixPrint} [\x20-\x7E] (95)
+ \p{PosixPunct} Graphical characters that aren't Word
+ characters = [\x21-\x2F\x3A-\x40\x5B-
+ \x60\x7B-\x7E] (32)
+ \p{PosixSpace} \t \n, \x0B, \f, \r, and ' ' (6)
+ \p{PosixUpper} [A-Z] (26)
+ T \p{Present_In: 1.1} \p{Age=1.1} (Short: \p{In=1.1}) (Perl
+ extension) (33_979)
+ T \p{Present_In: 2.0} Code point's usage introduced in version
+ 2.0 or earlier (Short: \p{In=2.0}) (Perl
+ extension) (178_500)
+ T \p{Present_In: 2.1} Code point's usage introduced in version
+ 2.1 or earlier (Short: \p{In=2.1}) (Perl
+ extension) (178_502)
+ T \p{Present_In: 3.0} Code point's usage introduced in version
+ 3.0 or earlier (Short: \p{In=3.0}) (Perl
+ extension) (188_809)
+ T \p{Present_In: 3.1} Code point's usage introduced in version
+ 3.1 or earlier (Short: \p{In=3.1}) (Perl
+ extension) (233_787)
+ T \p{Present_In: 3.2} Code point's usage introduced in version
+ 3.2 or earlier (Short: \p{In=3.2}) (Perl
+ extension) (234_803)
+ T \p{Present_In: 4.0} Code point's usage introduced in version
+ 4.0 or earlier (Short: \p{In=4.0}) (Perl
+ extension) (236_029)
+ T \p{Present_In: 4.1} Code point's usage introduced in version
+ 4.1 or earlier (Short: \p{In=4.1}) (Perl
+ extension) (237_302)
+ T \p{Present_In: 5.0} Code point's usage introduced in version
+ 5.0 or earlier (Short: \p{In=5.0}) (Perl
+ extension) (238_671)
+ T \p{Present_In: 5.1} Code point's usage introduced in version
+ 5.1 or earlier (Short: \p{In=5.1}) (Perl
+ extension) (240_295)
+ T \p{Present_In: 5.2} Code point's usage introduced in version
+ 5.2 or earlier (Short: \p{In=5.2}) (Perl
+ extension) (246_943)
+ \p{Present_In: Unassigned} \p{Age=Unassigned} (Short: \p{In=
+ Unassigned}) (Perl extension) (867_169)
+ \p{Print} Characters that are graphical plus space
+ characters (but no controls) (244_762)
+ \p{Private_Use} \p{General_Category=Private_Use} (Short:
+ \p{Co}; NOT \p{Private_Use_Area})
+ (137_468)
+ X \p{Private_Use_Area} \p{Block=Private_Use_Area} (Short:
+ \p{InPrivateUse}) (6400)
+ \p{Prti} \p{Inscriptional_Parthian} (= \p{Script=
+ Inscriptional_Parthian}) (NOT \p{Block=
+ Inscriptional_Parthian}) (30)
+ \p{Ps} \p{Open_Punctuation} (=
+ \p{General_Category=Open_Punctuation})
+ (72)
+ \p{Punct} \p{General_Category=Punctuation} (Short:
+ \p{P}) (585)
+ \p{Punctuation} \p{Punct} (= \p{General_Category=
+ Punctuation}) (585)
+ \p{Qaac} \p{Coptic} (= \p{Script=Coptic}) (NOT
+ \p{Block=Coptic}) (135)
+ \p{Qaai} \p{Inherited} (= \p{Script=Inherited})
+ (523)
+ \p{QMark} \p{Quotation_Mark} (= \p{Quotation_Mark=
+ Y}) (29)
+ \p{QMark: *} \p{Quotation_Mark: *}
+ \p{Quotation_Mark} \p{Quotation_Mark=Y} (Short: \p{QMark})
+ (29)
+ \p{Quotation_Mark: N*} (Short: \p{QMark=N}, \P{QMark}) (1_114_083)
+ \p{Quotation_Mark: Y*} (Short: \p{QMark=Y}, \p{QMark}) (29)
+ \p{Radical} \p{Radical=Y} (329)
+ \p{Radical: N*} (Single: \P{Radical}) (1_113_783)
+ \p{Radical: Y*} (Single: \p{Radical}) (329)
+ \p{Rejang} \p{Script=Rejang} (Short: \p{Rjng}; NOT
+ \p{Block=Rejang}) (37)
+ \p{Rjng} \p{Rejang} (= \p{Script=Rejang}) (NOT
+ \p{Block=Rejang}) (37)
+ X \p{Rumi_Numeral_Symbols} \p{Block=Rumi_Numeral_Symbols} (32)
+ \p{Runic} \p{Script=Runic} (Short: \p{Runr}; NOT
+ \p{Block=Runic}) (78)
+ \p{Runr} \p{Runic} (= \p{Script=Runic}) (NOT
+ \p{Block=Runic}) (78)
+ \p{S} \p{Symbol} (= \p{General_Category=Symbol})
+ (4499)
+ \p{Samaritan} \p{Script=Samaritan} (Short: \p{Samr}; NOT
+ \p{Block=Samaritan}) (61)
+ \p{Samr} \p{Samaritan} (= \p{Script=Samaritan})
+ (NOT \p{Block=Samaritan}) (61)
+ \p{Sarb} \p{Old_South_Arabian} (= \p{Script=
+ Old_South_Arabian}) (32)
+ \p{Saur} \p{Saurashtra} (= \p{Script=Saurashtra})
+ (NOT \p{Block=Saurashtra}) (81)
+ \p{Saurashtra} \p{Script=Saurashtra} (Short: \p{Saur};
+ NOT \p{Block=Saurashtra}) (81)
+ \p{SB: *} \p{Sentence_Break: *}
+ \p{Sc} \p{Currency_Symbol} (=
+ \p{General_Category=Currency_Symbol})
+ (46)
+ \p{Sc: *} \p{Script: *}
+ \p{Script: Arab} \p{Script=Arabic} (1030)
+ \p{Script: Arabic} (Short: \p{Sc=Arab}, \p{Arab}) (1030)
+ \p{Script: Armenian} (Short: \p{Sc=Armn}, \p{Armn}) (90)
+ \p{Script: Armi} \p{Script=Imperial_Aramaic} (31)
+ \p{Script: Armn} \p{Script=Armenian} (90)
+ \p{Script: Avestan} (Short: \p{Sc=Avst}, \p{Avst}) (61)
+ \p{Script: Avst} \p{Script=Avestan} (61)
+ \p{Script: Bali} \p{Script=Balinese} (121)
+ \p{Script: Balinese} (Short: \p{Sc=Bali}, \p{Bali}) (121)
+ \p{Script: Bamu} \p{Script=Bamum} (88)
+ \p{Script: Bamum} (Short: \p{Sc=Bamu}, \p{Bamu}) (88)
+ \p{Script: Beng} \p{Script=Bengali} (92)
+ \p{Script: Bengali} (Short: \p{Sc=Beng}, \p{Beng}) (92)
+ \p{Script: Bopo} \p{Script=Bopomofo} (65)
+ \p{Script: Bopomofo} (Short: \p{Sc=Bopo}, \p{Bopo}) (65)
+ \p{Script: Brai} \p{Script=Braille} (256)
+ \p{Script: Braille} (Short: \p{Sc=Brai}, \p{Brai}) (256)
+ \p{Script: Bugi} \p{Script=Buginese} (30)
+ \p{Script: Buginese} (Short: \p{Sc=Bugi}, \p{Bugi}) (30)
+ \p{Script: Buhd} \p{Script=Buhid} (20)
+ \p{Script: Buhid} (Short: \p{Sc=Buhd}, \p{Buhd}) (20)
+ \p{Script: Canadian_Aboriginal} (Short: \p{Sc=Cans}, \p{Cans})
+ (710)
+ \p{Script: Cans} \p{Script=Canadian_Aboriginal} (710)
+ \p{Script: Cari} \p{Script=Carian} (49)
+ \p{Script: Carian} (Short: \p{Sc=Cari}, \p{Cari}) (49)
+ \p{Script: Cham} (Short: \p{Sc=Cham}, \p{Cham}) (83)
+ \p{Script: Cher} \p{Script=Cherokee} (85)
+ \p{Script: Cherokee} (Short: \p{Sc=Cher}, \p{Cher}) (85)
+ \p{Script: Common} (Short: \p{Sc=Zyyy}, \p{Zyyy}) (5395)
+ \p{Script: Copt} \p{Script=Coptic} (135)
+ \p{Script: Coptic} (Short: \p{Sc=Copt}, \p{Copt}) (135)
+ \p{Script: Cprt} \p{Script=Cypriot} (55)
+ \p{Script: Cuneiform} (Short: \p{Sc=Xsux}, \p{Xsux}) (982)
+ \p{Script: Cypriot} (Short: \p{Sc=Cprt}, \p{Cprt}) (55)
+ \p{Script: Cyrillic} (Short: \p{Sc=Cyrl}, \p{Cyrl}) (404)
+ \p{Script: Cyrl} \p{Script=Cyrillic} (404)
+ \p{Script: Deseret} (Short: \p{Sc=Dsrt}, \p{Dsrt}) (80)
+ \p{Script: Deva} \p{Script=Devanagari} (140)
+ \p{Script: Devanagari} (Short: \p{Sc=Deva}, \p{Deva}) (140)
+ \p{Script: Dsrt} \p{Script=Deseret} (80)
+ \p{Script: Egyp} \p{Script=Egyptian_Hieroglyphs} (1071)
+ \p{Script: Egyptian_Hieroglyphs} (Short: \p{Sc=Egyp}, \p{Egyp})
+ (1071)
+ \p{Script: Ethi} \p{Script=Ethiopic} (461)
+ \p{Script: Ethiopic} (Short: \p{Sc=Ethi}, \p{Ethi}) (461)
+ \p{Script: Geor} \p{Script=Georgian} (120)
+ \p{Script: Georgian} (Short: \p{Sc=Geor}, \p{Geor}) (120)
+ \p{Script: Glag} \p{Script=Glagolitic} (94)
+ \p{Script: Glagolitic} (Short: \p{Sc=Glag}, \p{Glag}) (94)
+ \p{Script: Goth} \p{Script=Gothic} (27)
+ \p{Script: Gothic} (Short: \p{Sc=Goth}, \p{Goth}) (27)
+ \p{Script: Greek} (Short: \p{Sc=Grek}, \p{Grek}) (511)
+ \p{Script: Grek} \p{Script=Greek} (511)
+ \p{Script: Gujarati} (Short: \p{Sc=Gujr}, \p{Gujr}) (83)
+ \p{Script: Gujr} \p{Script=Gujarati} (83)
+ \p{Script: Gurmukhi} (Short: \p{Sc=Guru}, \p{Guru}) (79)
+ \p{Script: Guru} \p{Script=Gurmukhi} (79)
+ \p{Script: Han} (Short: \p{Sc=Han}, \p{Han}) (75_738)
+ \p{Script: Hang} \p{Script=Hangul} (11_737)
+ \p{Script: Hangul} (Short: \p{Sc=Hang}, \p{Hang}) (11_737)
+ \p{Script: Hani} \p{Script=Han} (75_738)
+ \p{Script: Hano} \p{Script=Hanunoo} (21)
+ \p{Script: Hanunoo} (Short: \p{Sc=Hano}, \p{Hano}) (21)
+ \p{Script: Hebr} \p{Script=Hebrew} (133)
+ \p{Script: Hebrew} (Short: \p{Sc=Hebr}, \p{Hebr}) (133)
+ \p{Script: Hira} \p{Script=Hiragana} (90)
+ \p{Script: Hiragana} (Short: \p{Sc=Hira}, \p{Hira}) (90)
+ \p{Script: Imperial_Aramaic} (Short: \p{Sc=Armi}, \p{Armi}) (31)
+ \p{Script: Inherited} (Short: \p{Sc=Zinh}, \p{Zinh}) (523)
+ \p{Script: Inscriptional_Pahlavi} (Short: \p{Sc=Phli}, \p{Phli})
+ (27)
+ \p{Script: Inscriptional_Parthian} (Short: \p{Sc=Prti}, \p{Prti})
+ (30)
+ \p{Script: Ital} \p{Script=Old_Italic} (35)
+ \p{Script: Java} \p{Script=Javanese} (91)
+ \p{Script: Javanese} (Short: \p{Sc=Java}, \p{Java}) (91)
+ \p{Script: Kaithi} (Short: \p{Sc=Kthi}, \p{Kthi}) (66)
+ \p{Script: Kali} \p{Script=Kayah_Li} (48)
+ \p{Script: Kana} \p{Script=Katakana} (299)
+ \p{Script: Kannada} (Short: \p{Sc=Knda}, \p{Knda}) (84)
+ \p{Script: Katakana} (Short: \p{Sc=Kana}, \p{Kana}) (299)
+ \p{Script: Kayah_Li} (Short: \p{Sc=Kali}, \p{Kali}) (48)
+ \p{Script: Khar} \p{Script=Kharoshthi} (65)
+ \p{Script: Kharoshthi} (Short: \p{Sc=Khar}, \p{Khar}) (65)
+ \p{Script: Khmer} (Short: \p{Sc=Khmr}, \p{Khmr}) (146)
+ \p{Script: Khmr} \p{Script=Khmer} (146)
+ \p{Script: Knda} \p{Script=Kannada} (84)
+ \p{Script: Kthi} \p{Script=Kaithi} (66)
+ \p{Script: Lana} \p{Script=Tai_Tham} (127)
+ \p{Script: Lao} (Short: \p{Sc=Lao}, \p{Lao}) (65)
+ \p{Script: Laoo} \p{Script=Lao} (65)
+ \p{Script: Latin} (Short: \p{Sc=Latn}, \p{Latn}) (1244)
+ \p{Script: Latn} \p{Script=Latin} (1244)
+ \p{Script: Lepc} \p{Script=Lepcha} (74)
+ \p{Script: Lepcha} (Short: \p{Sc=Lepc}, \p{Lepc}) (74)
+ \p{Script: Limb} \p{Script=Limbu} (66)
+ \p{Script: Limbu} (Short: \p{Sc=Limb}, \p{Limb}) (66)
+ \p{Script: Linb} \p{Script=Linear_B} (211)
+ \p{Script: Linear_B} (Short: \p{Sc=Linb}, \p{Linb}) (211)
+ \p{Script: Lisu} (Short: \p{Sc=Lisu}, \p{Lisu}) (48)
+ \p{Script: Lyci} \p{Script=Lycian} (29)
+ \p{Script: Lycian} (Short: \p{Sc=Lyci}, \p{Lyci}) (29)
+ \p{Script: Lydi} \p{Script=Lydian} (27)
+ \p{Script: Lydian} (Short: \p{Sc=Lydi}, \p{Lydi}) (27)
+ \p{Script: Malayalam} (Short: \p{Sc=Mlym}, \p{Mlym}) (95)
+ \p{Script: Meetei_Mayek} (Short: \p{Sc=Mtei}, \p{Mtei}) (56)
+ \p{Script: Mlym} \p{Script=Malayalam} (95)
+ \p{Script: Mong} \p{Script=Mongolian} (153)
+ \p{Script: Mongolian} (Short: \p{Sc=Mong}, \p{Mong}) (153)
+ \p{Script: Mtei} \p{Script=Meetei_Mayek} (56)
+ \p{Script: Myanmar} (Short: \p{Sc=Mymr}, \p{Mymr}) (188)
+ \p{Script: Mymr} \p{Script=Myanmar} (188)
+ \p{Script: New_Tai_Lue} (Short: \p{Sc=Talu}, \p{Talu}) (83)
+ \p{Script: Nko} (Short: \p{Sc=Nko}, \p{Nko}) (59)
+ \p{Script: Nkoo} \p{Script=Nko} (59)
+ \p{Script: Ogam} \p{Script=Ogham} (29)
+ \p{Script: Ogham} (Short: \p{Sc=Ogam}, \p{Ogam}) (29)
+ \p{Script: Ol_Chiki} (Short: \p{Sc=Olck}, \p{Olck}) (48)
+ \p{Script: Olck} \p{Script=Ol_Chiki} (48)
+ \p{Script: Old_Italic} (Short: \p{Sc=Ital}, \p{Ital}) (35)
+ \p{Script: Old_Persian} (Short: \p{Sc=Xpeo}, \p{Xpeo}) (50)
+ \p{Script: Old_South_Arabian} (Short: \p{Sc=Sarb}, \p{Sarb}) (32)
+ \p{Script: Old_Turkic} (Short: \p{Sc=Orkh}, \p{Orkh}) (73)
+ \p{Script: Oriya} (Short: \p{Sc=Orya}, \p{Orya}) (84)
+ \p{Script: Orkh} \p{Script=Old_Turkic} (73)
+ \p{Script: Orya} \p{Script=Oriya} (84)
+ \p{Script: Osma} \p{Script=Osmanya} (40)
+ \p{Script: Osmanya} (Short: \p{Sc=Osma}, \p{Osma}) (40)
+ \p{Script: Phag} \p{Script=Phags_Pa} (56)
+ \p{Script: Phags_Pa} (Short: \p{Sc=Phag}, \p{Phag}) (56)
+ \p{Script: Phli} \p{Script=Inscriptional_Pahlavi} (27)
+ \p{Script: Phnx} \p{Script=Phoenician} (29)
+ \p{Script: Phoenician} (Short: \p{Sc=Phnx}, \p{Phnx}) (29)
+ \p{Script: Prti} \p{Script=Inscriptional_Parthian} (30)
+ \p{Script: Qaac} \p{Script=Coptic} (135)
+ \p{Script: Qaai} \p{Script=Inherited} (523)
+ \p{Script: Rejang} (Short: \p{Sc=Rjng}, \p{Rjng}) (37)
+ \p{Script: Rjng} \p{Script=Rejang} (37)
+ \p{Script: Runic} (Short: \p{Sc=Runr}, \p{Runr}) (78)
+ \p{Script: Runr} \p{Script=Runic} (78)
+ \p{Script: Samaritan} (Short: \p{Sc=Samr}, \p{Samr}) (61)
+ \p{Script: Samr} \p{Script=Samaritan} (61)
+ \p{Script: Sarb} \p{Script=Old_South_Arabian} (32)
+ \p{Script: Saur} \p{Script=Saurashtra} (81)
+ \p{Script: Saurashtra} (Short: \p{Sc=Saur}, \p{Saur}) (81)
+ \p{Script: Shavian} (Short: \p{Sc=Shaw}, \p{Shaw}) (48)
+ \p{Script: Shaw} \p{Script=Shavian} (48)
+ \p{Script: Sinh} \p{Script=Sinhala} (80)
+ \p{Script: Sinhala} (Short: \p{Sc=Sinh}, \p{Sinh}) (80)
+ \p{Script: Sund} \p{Script=Sundanese} (55)
+ \p{Script: Sundanese} (Short: \p{Sc=Sund}, \p{Sund}) (55)
+ \p{Script: Sylo} \p{Script=Syloti_Nagri} (44)
+ \p{Script: Syloti_Nagri} (Short: \p{Sc=Sylo}, \p{Sylo}) (44)
+ \p{Script: Syrc} \p{Script=Syriac} (77)
+ \p{Script: Syriac} (Short: \p{Sc=Syrc}, \p{Syrc}) (77)
+ \p{Script: Tagalog} (Short: \p{Sc=Tglg}, \p{Tglg}) (20)
+ \p{Script: Tagb} \p{Script=Tagbanwa} (18)
+ \p{Script: Tagbanwa} (Short: \p{Sc=Tagb}, \p{Tagb}) (18)
+ \p{Script: Tai_Le} (Short: \p{Sc=Tale}, \p{Tale}) (35)
+ \p{Script: Tai_Tham} (Short: \p{Sc=Lana}, \p{Lana}) (127)
+ \p{Script: Tai_Viet} (Short: \p{Sc=Tavt}, \p{Tavt}) (72)
+ \p{Script: Tale} \p{Script=Tai_Le} (35)
+ \p{Script: Talu} \p{Script=New_Tai_Lue} (83)
+ \p{Script: Tamil} (Short: \p{Sc=Taml}, \p{Taml}) (72)
+ \p{Script: Taml} \p{Script=Tamil} (72)
+ \p{Script: Tavt} \p{Script=Tai_Viet} (72)
+ \p{Script: Telu} \p{Script=Telugu} (93)
+ \p{Script: Telugu} (Short: \p{Sc=Telu}, \p{Telu}) (93)
+ \p{Script: Tfng} \p{Script=Tifinagh} (55)
+ \p{Script: Tglg} \p{Script=Tagalog} (20)
+ \p{Script: Thaa} \p{Script=Thaana} (50)
+ \p{Script: Thaana} (Short: \p{Sc=Thaa}, \p{Thaa}) (50)
+ \p{Script: Thai} (Short: \p{Sc=Thai}, \p{Thai}) (86)
+ \p{Script: Tibetan} (Short: \p{Sc=Tibt}, \p{Tibt}) (201)
+ \p{Script: Tibt} \p{Script=Tibetan} (201)
+ \p{Script: Tifinagh} (Short: \p{Sc=Tfng}, \p{Tfng}) (55)
+ \p{Script: Ugar} \p{Script=Ugaritic} (31)
+ \p{Script: Ugaritic} (Short: \p{Sc=Ugar}, \p{Ugar}) (31)
+ \p{Script: Unknown} (Short: \p{Sc=Zzzz}, \p{Zzzz}) (1_006_751)
+ \p{Script: Vai} (Short: \p{Sc=Vai}, \p{Vai}) (300)
+ \p{Script: Vaii} \p{Script=Vai} (300)
+ \p{Script: Xpeo} \p{Script=Old_Persian} (50)
+ \p{Script: Xsux} \p{Script=Cuneiform} (982)
+ \p{Script: Yi} (Short: \p{Sc=Yi}, \p{Yi}) (1220)
+ \p{Script: Yiii} \p{Script=Yi} (1220)
+ \p{Script: Zinh} \p{Script=Inherited} (523)
+ \p{Script: Zyyy} \p{Script=Common} (5395)
+ \p{Script: Zzzz} \p{Script=Unknown} (1_006_751)
+ \p{SD} \p{Soft_Dotted} (= \p{Soft_Dotted=Y}) (46)
+ \p{SD: *} \p{Soft_Dotted: *}
+ \p{Sentence_Break: AT} \p{Sentence_Break=ATerm} (4)
+ \p{Sentence_Break: ATerm} (Short: \p{SB=AT}) (4)
+ \p{Sentence_Break: CL} \p{Sentence_Break=Close} (177)
+ \p{Sentence_Break: Close} (Short: \p{SB=CL}) (177)
+ \p{Sentence_Break: CR} (Short: \p{SB=CR}) (1)
+ \p{Sentence_Break: EX} \p{Sentence_Break=Extend} (1455)
+ \p{Sentence_Break: Extend} (Short: \p{SB=EX}) (1455)
+ \p{Sentence_Break: FO} \p{Sentence_Break=Format} (138)
+ \p{Sentence_Break: Format} (Short: \p{SB=FO}) (138)
+ \p{Sentence_Break: LE} \p{Sentence_Break=OLetter} (96_405)
+ \p{Sentence_Break: LF} (Short: \p{SB=LF}) (1)
+ \p{Sentence_Break: LO} \p{Sentence_Break=Lower} (1907)
+ \p{Sentence_Break: Lower} (Short: \p{SB=LO}) (1907)
+ \p{Sentence_Break: NU} \p{Sentence_Break=Numeric} (403)
+ \p{Sentence_Break: Numeric} (Short: \p{SB=NU}) (403)
+ \p{Sentence_Break: OLetter} (Short: \p{SB=LE}) (96_405)
+ \p{Sentence_Break: Other} (Short: \p{SB=XX}) (1_012_008)
+ \p{Sentence_Break: SC} \p{Sentence_Break=SContinue} (26)
+ \p{Sentence_Break: SContinue} (Short: \p{SB=SC}) (26)
+ \p{Sentence_Break: SE} \p{Sentence_Break=Sep} (3)
+ \p{Sentence_Break: Sep} (Short: \p{SB=SE}) (3)
+ \p{Sentence_Break: Sp} (Short: \p{SB=Sp}) (21)
+ \p{Sentence_Break: ST} \p{Sentence_Break=STerm} (63)
+ \p{Sentence_Break: STerm} (Short: \p{SB=ST}) (63)
+ \p{Sentence_Break: UP} \p{Sentence_Break=Upper} (1500)
+ \p{Sentence_Break: Upper} (Short: \p{SB=UP}) (1500)
+ \p{Sentence_Break: XX} \p{Sentence_Break=Other} (1_012_008)
+ \p{Separator} \p{General_Category=Separator} (Short:
+ \p{Z}) (20)
+ \p{Shavian} \p{Script=Shavian} (Short: \p{Shaw}) (48)
+ \p{Shaw} \p{Shavian} (= \p{Script=Shavian}) (48)
+ \p{Sinh} \p{Sinhala} (= \p{Script=Sinhala}) (NOT
+ \p{Block=Sinhala}) (80)
+ \p{Sinhala} \p{Script=Sinhala} (Short: \p{Sinh}; NOT
+ \p{Block=Sinhala}) (80)
+ \p{Sk} \p{Modifier_Symbol} (=
+ \p{General_Category=Modifier_Symbol})
+ (99)
+ \p{Sm} \p{Math_Symbol} (= \p{General_Category=
+ Math_Symbol}) (945)
+ X \p{Small_Form_Variants} \p{Block=Small_Form_Variants} (32)
+ \p{So} \p{Other_Symbol} (= \p{General_Category=
+ Other_Symbol}) (3409)
+ \p{Soft_Dotted} \p{Soft_Dotted=Y} (Short: \p{SD}) (46)
+ \p{Soft_Dotted: N*} (Short: \p{SD=N}, \P{SD}) (1_114_066)
+ \p{Soft_Dotted: Y*} (Short: \p{SD=Y}, \p{SD}) (46)
+ \p{Space} \p{White_Space=Y} \s including beyond
+ ASCII plus vertical tab (26)
+ \p{Space: *} \p{White_Space: *}
+ \p{Space_Separator} \p{General_Category=Space_Separator}
+ (Short: \p{Zs}) (18)
+ \p{SpacePerl} \s, including beyond ASCII (25)
+ \p{Spacing_Mark} \p{General_Category=Spacing_Mark} (Short:
+ \p{Mc}) (276)
+ X \p{Spacing_Modifier_Letters} \p{Block=Spacing_Modifier_Letters}
+ (80)
+ X \p{Specials} \p{Block=Specials} (16)
+ \p{STerm} \p{STerm=Y} (66)
+ \p{STerm: N*} (Single: \P{STerm}) (1_114_046)
+ \p{STerm: Y*} (Single: \p{STerm}) (66)
+ \p{Sund} \p{Sundanese} (= \p{Script=Sundanese})
+ (NOT \p{Block=Sundanese}) (55)
+ \p{Sundanese} \p{Script=Sundanese} (Short: \p{Sund}; NOT
+ \p{Block=Sundanese}) (55)
+ X \p{Superscripts_And_Subscripts} \p{Block=
+ Superscripts_And_Subscripts} (48)
+ X \p{Supplemental_Arrows_A} \p{Block=Supplemental_Arrows_A} (16)
+ X \p{Supplemental_Arrows_B} \p{Block=Supplemental_Arrows_B} (128)
+ X \p{Supplemental_Mathematical_Operators} \p{Block=
+ Supplemental_Mathematical_Operators}
+ (256)
+ X \p{Supplemental_Punctuation} \p{Block=Supplemental_Punctuation}
+ (128)
+ X \p{Supplementary_Private_Use_Area_A} \p{Block=
+ Supplementary_Private_Use_Area_A}
+ (65_536)
+ X \p{Supplementary_Private_Use_Area_B} \p{Block=
+ Supplementary_Private_Use_Area_B}
+ (65_536)
+ \p{Surrogate} \p{General_Category=Surrogate} (Short:
+ \p{Cs}) (2048)
+ \p{Sylo} \p{Syloti_Nagri} (= \p{Script=
+ Syloti_Nagri}) (NOT \p{Block=
+ Syloti_Nagri}) (44)
+ \p{Syloti_Nagri} \p{Script=Syloti_Nagri} (Short: \p{Sylo};
+ NOT \p{Block=Syloti_Nagri}) (44)
+ \p{Symbol} \p{General_Category=Symbol} (Short: \p{S})
+ (4499)
+ \p{Syrc} \p{Syriac} (= \p{Script=Syriac}) (NOT
+ \p{Block=Syriac}) (77)
+ \p{Syriac} \p{Script=Syriac} (Short: \p{Syrc}; NOT
+ \p{Block=Syriac}) (77)
+ \p{Tagalog} \p{Script=Tagalog} (Short: \p{Tglg}; NOT
+ \p{Block=Tagalog}) (20)
+ \p{Tagb} \p{Tagbanwa} (= \p{Script=Tagbanwa}) (NOT
+ \p{Block=Tagbanwa}) (18)
+ \p{Tagbanwa} \p{Script=Tagbanwa} (Short: \p{Tagb}; NOT
+ \p{Block=Tagbanwa}) (18)
+ X \p{Tags} \p{Block=Tags} (128)
+ \p{Tai_Le} \p{Script=Tai_Le} (Short: \p{Tale}; NOT
+ \p{Block=Tai_Le}) (35)
+ \p{Tai_Tham} \p{Script=Tai_Tham} (Short: \p{Lana}; NOT
+ \p{Block=Tai_Tham}) (127)
+ \p{Tai_Viet} \p{Script=Tai_Viet} (Short: \p{Tavt}; NOT
+ \p{Block=Tai_Viet}) (72)
+ X \p{Tai_Xuan_Jing_Symbols} \p{Block=Tai_Xuan_Jing_Symbols} (96)
+ \p{Tale} \p{Tai_Le} (= \p{Script=Tai_Le}) (NOT
+ \p{Block=Tai_Le}) (35)
+ \p{Talu} \p{New_Tai_Lue} (= \p{Script=New_Tai_Lue})
+ (NOT \p{Block=New_Tai_Lue}) (83)
+ \p{Tamil} \p{Script=Tamil} (Short: \p{Taml}; NOT
+ \p{Block=Tamil}) (72)
+ \p{Taml} \p{Tamil} (= \p{Script=Tamil}) (NOT
+ \p{Block=Tamil}) (72)
+ \p{Tavt} \p{Tai_Viet} (= \p{Script=Tai_Viet}) (NOT
+ \p{Block=Tai_Viet}) (72)
+ \p{Telu} \p{Telugu} (= \p{Script=Telugu}) (NOT
+ \p{Block=Telugu}) (93)
+ \p{Telugu} \p{Script=Telugu} (Short: \p{Telu}; NOT
+ \p{Block=Telugu}) (93)
+ \p{Term} \p{Terminal_Punctuation} (=
+ \p{Terminal_Punctuation=Y}) (161)
+ \p{Term: *} \p{Terminal_Punctuation: *}
+ \p{Terminal_Punctuation} \p{Terminal_Punctuation=Y} (Short:
+ \p{Term}) (161)
+ \p{Terminal_Punctuation: N*} (Short: \p{Term=N}, \P{Term})
+ (1_113_951)
+ \p{Terminal_Punctuation: Y*} (Short: \p{Term=Y}, \p{Term}) (161)
+ \p{Tfng} \p{Tifinagh} (= \p{Script=Tifinagh}) (NOT
+ \p{Block=Tifinagh}) (55)
+ \p{Tglg} \p{Tagalog} (= \p{Script=Tagalog}) (NOT
+ \p{Block=Tagalog}) (20)
+ \p{Thaa} \p{Thaana} (= \p{Script=Thaana}) (NOT
+ \p{Block=Thaana}) (50)
+ \p{Thaana} \p{Script=Thaana} (Short: \p{Thaa}; NOT
+ \p{Block=Thaana}) (50)
+ \p{Thai} \p{Script=Thai} (NOT \p{Block=Thai}) (86)
+ \p{Tibetan} \p{Script=Tibetan} (Short: \p{Tibt}; NOT
+ \p{Block=Tibetan}) (201)
+ \p{Tibt} \p{Tibetan} (= \p{Script=Tibetan}) (NOT
+ \p{Block=Tibetan}) (201)
+ \p{Tifinagh} \p{Script=Tifinagh} (Short: \p{Tfng}; NOT
+ \p{Block=Tifinagh}) (55)
+ \p{Title} \p{General_Category=Titlecase_Letter}
+ (Short: \p{Lt}) (31)
+ \p{Titlecase_Letter} \p{Title} (= \p{General_Category=
+ Titlecase_Letter}) (31)
+ \p{Ugar} \p{Ugaritic} (= \p{Script=Ugaritic}) (NOT
+ \p{Block=Ugaritic}) (31)
+ \p{Ugaritic} \p{Script=Ugaritic} (Short: \p{Ugar}; NOT
+ \p{Block=Ugaritic}) (31)
+ \p{UIdeo} \p{Unified_Ideograph} (=
+ \p{Unified_Ideograph=Y}) (74_394)
+ \p{UIdeo: *} \p{Unified_Ideograph: *}
+ \p{Unassigned} \p{General_Category=Unassigned} (Short:
+ \p{Cn}) (867_235)
+ X \p{Unified_Canadian_Aboriginal_Syllabics} \p{Block=
+ Unified_Canadian_Aboriginal_Syllabics}
+ (Short: \p{InCanadianSyllabics}) (640)
+ X \p{Unified_Canadian_Aboriginal_Syllabics_Extended} \p{Block=
+ Unified_Canadian_Aboriginal_Syllabics_-
+ Extended} (80)
+ \p{Unified_Ideograph} \p{Unified_Ideograph=Y} (Short: \p{UIdeo})
+ (74_394)
+ \p{Unified_Ideograph: N*} (Short: \p{UIdeo=N}, \P{UIdeo})
+ (1_039_718)
+ \p{Unified_Ideograph: Y*} (Short: \p{UIdeo=Y}, \p{UIdeo}) (74_394)
+ \p{Unknown} \p{Script=Unknown} (Short: \p{Zzzz})
+ (1_006_751)
+ \p{Upper} \p{Uppercase=Y} (1469)
+ \p{Upper: *} \p{Uppercase: *}
+ \p{Uppercase} \p{Upper} (= \p{Uppercase=Y}) (1469)
+ \p{Uppercase: N*} (Short: \p{Upper=N}, \P{Upper}) (1_112_643)
+ \p{Uppercase: Y*} (Short: \p{Upper=Y}, \p{Upper}) (1469)
+ \p{Uppercase_Letter} \p{General_Category=Uppercase_Letter}
+ (Short: \p{Lu}) (1427)
+ \p{Vai} \p{Script=Vai} (NOT \p{Block=Vai}) (300)
+ \p{Vaii} \p{Vai} (= \p{Script=Vai}) (NOT \p{Block=
+ Vai}) (300)
+ \p{Variation_Selector} \p{Variation_Selector=Y} (Short: \p{VS})
+ (259)
+ \p{Variation_Selector: N*} (Short: \p{VS=N}, \P{VS}) (1_113_853)
+ \p{Variation_Selector: Y*} (Short: \p{VS=Y}, \p{VS}) (259)
+ X \p{Variation_Selectors} \p{Block=Variation_Selectors} (16)
+ X \p{Variation_Selectors_Supplement} \p{Block=
+ Variation_Selectors_Supplement} (240)
+ X \p{Vedic_Extensions} \p{Block=Vedic_Extensions} (48)
+ X \p{Vertical_Forms} \p{Block=Vertical_Forms} (16)
+ \p{VertSpace} \v (7)
+ \p{VS} \p{Variation_Selector} (=
+ \p{Variation_Selector=Y}) (259)
+ \p{VS: *} \p{Variation_Selector: *}
+ \p{WB: *} \p{Word_Break: *}
+ \p{White_Space} \p{White_Space=Y} (Short: \p{WSpace}) (26)
+ \p{White_Space: N*} (Short: \p{Space=N}, \P{WSpace})
+ (1_114_086)
+ \p{White_Space: Y*} (Short: \p{Space=Y}, \p{WSpace}) (26)
+ \p{Word} \w, including beyond ASCII (101_685)
+ \p{Word_Break: ALetter} (Short: \p{WB=LE}) (23_694)
+ \p{Word_Break: CR} (Short: \p{WB=CR}) (1)
+ \p{Word_Break: EX} \p{Word_Break=ExtendNumLet} (10)
+ \p{Word_Break: Extend} (Short: \p{WB=Extend}) (1455)
+ \p{Word_Break: ExtendNumLet} (Short: \p{WB=EX}) (10)
+ \p{Word_Break: FO} \p{Word_Break=Format} (137)
+ \p{Word_Break: Format} (Short: \p{WB=FO}) (137)
+ \p{Word_Break: KA} \p{Word_Break=Katakana} (309)
+ \p{Word_Break: Katakana} (Short: \p{WB=KA}) (309)
+ \p{Word_Break: LE} \p{Word_Break=ALetter} (23_694)
+ \p{Word_Break: LF} (Short: \p{WB=LF}) (1)
+ \p{Word_Break: MB} \p{Word_Break=MidNumLet} (8)
+ \p{Word_Break: MidLetter} (Short: \p{WB=ML}) (8)
+ \p{Word_Break: MidNum} (Short: \p{WB=MN}) (15)
+ \p{Word_Break: MidNumLet} (Short: \p{WB=MB}) (8)
+ \p{Word_Break: ML} \p{Word_Break=MidLetter} (8)
+ \p{Word_Break: MN} \p{Word_Break=MidNum} (15)
+ \p{Word_Break: Newline} (Short: \p{WB=NL}) (5)
+ \p{Word_Break: NL} \p{Word_Break=Newline} (5)
+ \p{Word_Break: NU} \p{Word_Break=Numeric} (402)
+ \p{Word_Break: Numeric} (Short: \p{WB=NU}) (402)
+ \p{Word_Break: Other} (Short: \p{WB=XX}) (1_088_067)
+ \p{Word_Break: XX} \p{Word_Break=Other} (1_088_067)
+ \p{WSpace} \p{White_Space} (= \p{White_Space=Y}) (26)
+ \p{WSpace: *} \p{White_Space: *}
+ \p{XDigit} \p{Hex_Digit=Y} (Short: \p{Hex}) (44)
+ \p{XID_Continue} \p{XID_Continue=Y} (Short: \p{XIDC})
+ (101_615)
+ \p{XID_Continue: N*} (Short: \p{XIDC=N}, \P{XIDC}) (1_012_497)
+ \p{XID_Continue: Y*} (Short: \p{XIDC=Y}, \p{XIDC}) (101_615)
+ \p{XID_Start} \p{XID_Start=Y} (Short: \p{XIDS}) (99_741)
+ \p{XID_Start: N*} (Short: \p{XIDS=N}, \P{XIDS}) (1_014_371)
+ \p{XID_Start: Y*} (Short: \p{XIDS=Y}, \p{XIDS}) (99_741)
+ \p{XIDC} \p{XID_Continue} (= \p{XID_Continue=Y})
+ (101_615)
+ \p{XIDC: *} \p{XID_Continue: *}
+ \p{XIDS} \p{XID_Start} (= \p{XID_Start=Y}) (99_741)
+ \p{XIDS: *} \p{XID_Start: *}
+ \p{Xpeo} \p{Old_Persian} (= \p{Script=Old_Persian})
+ (NOT \p{Block=Old_Persian}) (50)
+ \p{Xsux} \p{Cuneiform} (= \p{Script=Cuneiform})
+ (NOT \p{Block=Cuneiform}) (982)
+ \p{Yi} \p{Script=Yi} (1220)
+ X \p{Yi_Radicals} \p{Block=Yi_Radicals} (64)
+ X \p{Yi_Syllables} \p{Block=Yi_Syllables} (1168)
+ \p{Yiii} \p{Yi} (= \p{Script=Yi}) (1220)
+ X \p{Yijing_Hexagram_Symbols} \p{Block=Yijing_Hexagram_Symbols} (64)
+ \p{Z} \p{Separator} (= \p{General_Category=
+ Separator}) (20)
+ \p{Zinh} \p{Inherited} (= \p{Script=Inherited})
+ (523)
+ \p{Zl} \p{Line_Separator} (= \p{General_Category=
+ Line_Separator}) (1)
+ \p{Zp} \p{Paragraph_Separator} (=
+ \p{General_Category=
+ Paragraph_Separator}) (1)
+ \p{Zs} \p{Space_Separator} (=
+ \p{General_Category=Space_Separator})
+ (18)
+ \p{Zyyy} \p{Common} (= \p{Script=Common}) (5395)
+ \p{Zzzz} \p{Unknown} (= \p{Script=Unknown})
+ (1_006_751)
+ T \p{_CanonDCIJ} (For internal use by Perl, not necessarily
+ stable) (= \p{Soft_Dotted=Y}) (46)
+ T \p{_Case_Ignorable} (For internal use by Perl, not necessarily
+ stable) (= \p{Case_Ignorable=Y}) (1632)
+ T \p{_CombAbove} (For internal use by Perl, not necessarily
+ stable) (= \p{Canonical_Combining_Class=
+ Above}) (318)
+ T \p{_X_Begin} (For internal use by Perl, not necessarily
+ stable) (1_113_907)
+ T \p{_X_Extend} (For internal use by Perl, not necessarily
+ stable) (1462)
+ T \p{_X_LV_LVT_V} (For internal use by Perl, not necessarily
+ stable) (11_267)
+
+
+
+=head2 Legal \p{} and \P{} constructs that match no characters
+
+Unicode has some property-value pairs that currently don't match anything.
+This happens generally either because they are obsolete, or for symmetry with
+other forms, but no language has yet been encoded that uses them. In this
+version of Unicode, the following match zero code points:
+
+=over 4
+
+=item \p{Canonical_Combining_Class=Attached_Below_Left}
+
+=item \p{Joining_Type=Left_Joining}
+
+=back
+
+
+
+=head1 Properties not accessible through \p{} and \P{}
+
+A few properties are accessible in Perl via various function calls only.
+These are:
+ Lowercase_Mapping lc() and lcfirst()
+ Titlecase_Mapping ucfirst()
+ Uppercase_Mapping uc()
+
+Case_Folding is accessible through the /i modifier in regular expressions.
+
+The Name property is accessible through the \N{} interpolation in
+double-quoted strings and regular expressions, but both usages require a C<use
+charnames;> to be specified, which also contains related functions viacode()
+and vianame().
+
+=head1 Unicode regular expression properties that are NOT accepted by Perl
+
+Perl will generate an error for a few character properties in Unicode when
+used in a regular expression. The non-Unihan ones are listed below, with the
+reasons they are not accepted, perhaps with work-arounds. The short names for
+the properties are listed enclosed in (parentheses).
+
+=over 4
+
+
+
+
+
+
+=item I<Expands_On_NFC> (XO_NFC)
+
+=item I<Expands_On_NFD> (XO_NFD)
+
+=item I<Expands_On_NFKC> (XO_NFKC)
+
+=item I<Expands_On_NFKD> (XO_NFKD)
+
+Easily computed, and yet doesn't cover the common encoding forms (UTF-16/8)
+
+
+
+
+
+=item I<Grapheme_Link> (Gr_Link)
+
+Deprecated by Unicode. Use ccc=vr (Canonical_Combining_Class=Virama) instead
+
+
+
+
+
+=item I<Jamo_Short_Name> (JSN)
+
+Used by Unicode internally for generating other properties and not intended to be used stand-alone
+
+
+
+
+
+=item I<Script=Katakana_Or_Hiragana> (sc=Hrkt)
+
+Obsolete. All code points previously matched by this have been moved to "Script=Common"
+
+
+
+
+
+
+
+
+=back
+
+An installation can choose to allow any of these to be matched by changing the
+controlling lists contained in the program C<$Config{privlib}>/F<unicore/mktables>
+and then re-running F<mktables>. (C<%Config> is available from the Config module).
+
+=head1 Files in the I<To> directory (for serious hackers only)
+
+All Unicode properties are really mappings (in the mathematical sense) from
+code points to their respective values. As part of its build process,
+Perl constructs tables containing these mappings for all properties that it
+deals with. But only a few of these are written out into files.
+Those written out are in the directory C<$Config{privlib}>/F<unicore/To/>
+(%Config is available from the Config module).
+
+Those ones written are ones needed by Perl internally during execution, or for
+which there is some demand, and those for which there is no access through the
+Perl core. Generally, properties that can be used in regular expression
+matching do not have their map tables written, like Script. Nor are the
+simplistic properties that have a better, more complete version, such as
+Simple_Uppercase_Mapping (Uppercase_Mapping is written instead).
+
+None of the properties in the I<To> directory are currently directly
+accessible through the Perl core, although some may be accessed indirectly.
+For example, the uc() function implements the Uppercase_Mapping property and
+uses the F<Upper.pl> file found in this directory.
+
+The available files with their properties (short names in parentheses),
+and any flags or comments about them, are:
+
+ Bmg.pl Bidi_Mirroring_Glyph (bmg)
+ Digit.pl Perl_Decimal_Digit
+ Fold.pl Case_Folding (cf)
+ Lower.pl Lowercase_Mapping (lc)
+ NFKCCF.pl NFKC_Casefold (NFKC_CF)
+ Title.pl Titlecase_Mapping (tc)
+ Upper.pl Uppercase_Mapping (uc)
+
+
+An installation can choose to change which files are generated by changing the
+controlling lists contained in the program C<$Config{privlib}>/F<unicore/mktables>
+and then re-running F<mktables>.
+
+Each of these files defines two hash entries to help reading programs decipher
+it. One of them looks like this:
+
+ $utf8::SwashInfo{'ToNAME'}{'format'} = 's';
+
+where 'NAME' is a name to indicate the property. For backwards compatibility,
+this is not necessarily the property's official Unicode name. (The 'To' is
+also for backwards compatibility.) The hash entry gives the format of the
+mapping fields of the table, currently one of the following:
+
+ b binary
+ d single decimal digit
+ f floating point number
+ i integer
+ r rational: an integer or a fraction
+ s arbitrary string
+ x positive hex whole number; a code point
+
+
+This format applies only to the entries in the main body of the table.
+Entries defined in hashes or ones that are missing from the list can have a
+different format.
+
+The value that the missing entries have is given by the other SwashInfo hash
+entry line; it looks like this:
+
+ $utf8::SwashInfo{'ToNAME'}{'missing'} = 'NaN';
+
+This example line says that any Unicode code points not explicitly listed in
+the file have the value 'NaN' under the property indicated by NAME. If the
+value is the special string C<< <code point> >>, it means that the value for
+any missing code point is the code point itself. This happens, for example,
+in the file for Uppercase_Mapping (To/Upper.pl), in which code points like the
+character 'A', are missing because the uppercase of 'A' is itself.
+
+=head1 SEE ALSO
+
+L<http://www.unicode.org/reports/tr44/>
+
+L<perlrecharclass>
+
+L<perlunicode>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlunitut.pod b/Master/tlpkg/tlperl/lib/pods/perlunitut.pod
new file mode 100644
index 00000000000..fc352d5aad1
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlunitut.pod
@@ -0,0 +1,208 @@
+=head1 NAME
+
+perlunitut - Perl Unicode Tutorial
+
+=head1 DESCRIPTION
+
+The days of just flinging strings around are over. It's well established that
+modern programs need to be capable of communicating funny accented letters, and
+things like euro symbols. This means that programmers need new habits. It's
+easy to program Unicode capable software, but it does require discipline to do
+it right.
+
+There's a lot to know about character sets, and text encodings. It's probably
+best to spend a full day learning all this, but the basics can be learned in
+minutes.
+
+These are not the very basics, though. It is assumed that you already
+know the difference between bytes and characters, and realise (and accept!)
+that there are many different character sets and encodings, and that your
+program has to be explicit about them. Recommended reading is "The Absolute
+Minimum Every Software Developer Absolutely, Positively Must Know About Unicode
+and Character Sets (No Excuses!)" by Joel Spolsky, at
+L<http://joelonsoftware.com/articles/Unicode.html>.
+
+This tutorial speaks in rather absolute terms, and provides only a limited view
+of the wealth of character string related features that Perl has to offer. For
+most projects, this information will probably suffice.
+
+=head2 Definitions
+
+It's important to set a few things straight first. This is the most important
+part of this tutorial. This view may conflict with other information that you
+may have found on the web, but that's mostly because many sources are wrong.
+
+You may have to re-read this entire section a few times...
+
+=head3 Unicode
+
+B<Unicode> is a character set with room for lots of characters. The ordinal
+value of a character is called a B<code point>. (But in practice, the
+distinction between code point and character is blurred, so the terms often
+are used interchangeably.)
+
+There are many, many code points, but computers work with bytes, and a byte has
+room for only 256 values. Unicode has many more characters, so you need a
+method to make these accessible.
+
+Unicode is encoded using several competing encodings, of which UTF-8 is the
+most used. In a Unicode encoding, multiple subsequent bytes can be used to
+store a single code point, or simply: character.
+
+=head3 UTF-8
+
+B<UTF-8> is a Unicode encoding. Many people think that Unicode and UTF-8 are
+the same thing, but they're not. There are more Unicode encodings, but much of
+the world has standardized on UTF-8.
+
+UTF-8 treats the first 128 codepoints, 0..127, the same as ASCII. They take
+only one byte per character. All other characters are encoded as two or more
+(up to six) bytes using a complex scheme. Fortunately, Perl handles this for
+us, so we don't have to worry about this.
+
+=head3 Text strings (character strings)
+
+B<Text strings>, or B<character strings> are made of characters. Bytes are
+irrelevant here, and so are encodings. Each character is just that: the
+character.
+
+On a text string, you would do things like:
+
+ $text =~ s/foo/bar/;
+ if ($string =~ /^\d+$/) { ... }
+ $text = ucfirst $text;
+ my $character_count = length $text;
+
+The value of a character (C<ord>, C<chr>) is the corresponding Unicode code
+point.
+
+=head3 Binary strings (byte strings)
+
+B<Binary strings>, or B<byte strings> are made of bytes. Here, you don't have
+characters, just bytes. All communication with the outside world (anything
+outside of your current Perl process) is done in binary.
+
+On a binary string, you would do things like:
+
+ my (@length_content) = unpack "(V/a)*", $binary;
+ $binary =~ s/\x00\x0F/\xFF\xF0/; # for the brave :)
+ print {$fh} $binary;
+ my $byte_count = length $binary;
+
+=head3 Encoding
+
+B<Encoding> (as a verb) is the conversion from I<text> to I<binary>. To encode,
+you have to supply the target encoding, for example C<iso-8859-1> or C<UTF-8>.
+Some encodings, like the C<iso-8859> ("latin") range, do not support the full
+Unicode standard; characters that can't be represented are lost in the
+conversion.
+
+=head3 Decoding
+
+B<Decoding> is the conversion from I<binary> to I<text>. To decode, you have to
+know what encoding was used during the encoding phase. And most of all, it must
+be something decodable. It doesn't make much sense to decode a PNG image into a
+text string.
+
+=head3 Internal format
+
+Perl has an B<internal format>, an encoding that it uses to encode text strings
+so it can store them in memory. All text strings are in this internal format.
+In fact, text strings are never in any other format!
+
+You shouldn't worry about what this format is, because conversion is
+automatically done when you decode or encode.
+
+=head2 Your new toolkit
+
+Add to your standard heading the following line:
+
+ use Encode qw(encode decode);
+
+Or, if you're lazy, just:
+
+ use Encode;
+
+=head2 I/O flow (the actual 5 minute tutorial)
+
+The typical input/output flow of a program is:
+
+ 1. Receive and decode
+ 2. Process
+ 3. Encode and output
+
+If your input is binary, and is supposed to remain binary, you shouldn't decode
+it to a text string, of course. But in all other cases, you should decode it.
+
+Decoding can't happen reliably if you don't know how the data was encoded. If
+you get to choose, it's a good idea to standardize on UTF-8.
+
+ my $foo = decode('UTF-8', get 'http://example.com/');
+ my $bar = decode('ISO-8859-1', readline STDIN);
+ my $xyzzy = decode('Windows-1251', $cgi->param('foo'));
+
+Processing happens as you knew before. The only difference is that you're now
+using characters instead of bytes. That's very useful if you use things like
+C<substr>, or C<length>.
+
+It's important to realize that there are no bytes in a text string. Of course,
+Perl has its internal encoding to store the string in memory, but ignore that.
+If you have to do anything with the number of bytes, it's probably best to move
+that part to step 3, just after you've encoded the string. Then you know
+exactly how many bytes it will be in the destination string.
+
+The syntax for encoding text strings to binary strings is as simple as decoding:
+
+ $body = encode('UTF-8', $body);
+
+If you needed to know the length of the string in bytes, now's the perfect time
+for that. Because C<$body> is now a byte string, C<length> will report the
+number of bytes, instead of the number of characters. The number of
+characters is no longer known, because characters only exist in text strings.
+
+ my $byte_count = length $body;
+
+And if the protocol you're using supports a way of letting the recipient know
+which character encoding you used, please help the receiving end by using that
+feature! For example, E-mail and HTTP support MIME headers, so you can use the
+C<Content-Type> header. They can also have C<Content-Length> to indicate the
+number of I<bytes>, which is always a good idea to supply if the number is
+known.
+
+ "Content-Type: text/plain; charset=UTF-8",
+ "Content-Length: $byte_count"
+
+=head1 SUMMARY
+
+Decode everything you receive, encode everything you send out. (If it's text
+data.)
+
+=head1 Q and A (or FAQ)
+
+After reading this document, you ought to read L<perlunifaq> too.
+
+=head1 ACKNOWLEDGEMENTS
+
+Thanks to Johan Vromans from Squirrel Consultancy. His UTF-8 rants during the
+Amsterdam Perl Mongers meetings got me interested and determined to find out
+how to use character encodings in Perl in ways that don't break easily.
+
+Thanks to Gerard Goossen from TTY. His presentation "UTF-8 in the wild" (Dutch
+Perl Workshop 2006) inspired me to publish my thoughts and write this tutorial.
+
+Thanks to the people who asked about this kind of stuff in several Perl IRC
+channels, and have constantly reminded me that a simpler explanation was
+needed.
+
+Thanks to the people who reviewed this document for me, before it went public.
+They are: Benjamin Smith, Jan-Pieter Cornet, Johan Vromans, Lukas Mai, Nathan
+Gray.
+
+=head1 AUTHOR
+
+Juerd Waalboer <#####@juerd.nl>
+
+=head1 SEE ALSO
+
+L<perlunifaq>, L<perlunicode>, L<perluniintro>, L<Encode>
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlutil.pod b/Master/tlpkg/tlperl/lib/pods/perlutil.pod
new file mode 100644
index 00000000000..453248d2497
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlutil.pod
@@ -0,0 +1,309 @@
+=head1 NAME
+
+perlutil - utilities packaged with the Perl distribution
+
+=head1 DESCRIPTION
+
+Along with the Perl interpreter itself, the Perl distribution installs a
+range of utilities on your system. There are also several utilities
+which are used by the Perl distribution itself as part of the install
+process. This document exists to list all of these utilities, explain
+what they are for and provide pointers to each module's documentation,
+if appropriate.
+
+=head1 LIST OF UTILITIES
+
+=head2 Documentation
+
+=over 3
+
+=item L<perldoc|perldoc>
+
+The main interface to Perl's documentation is C<perldoc>, although
+if you're reading this, it's more than likely that you've already found
+it. F<perldoc> will extract and format the documentation from any file
+in the current directory, any Perl module installed on the system, or
+any of the standard documentation pages, such as this one. Use
+C<perldoc E<lt>nameE<gt>> to get information on any of the utilities
+described in this document.
+
+=item L<pod2man|pod2man> and L<pod2text|pod2text>
+
+If it's run from a terminal, F<perldoc> will usually call F<pod2man> to
+translate POD (Plain Old Documentation - see L<perlpod> for an
+explanation) into a manpage, and then run F<man> to display it; if
+F<man> isn't available, F<pod2text> will be used instead and the output
+piped through your favourite pager.
+
+=item L<pod2html|pod2html> and L<pod2latex|pod2latex>
+
+As well as these two, there are two other converters: F<pod2html> will
+produce HTML pages from POD, and F<pod2latex>, which produces LaTeX
+files.
+
+=item L<pod2usage|pod2usage>
+
+If you just want to know how to use the utilities described here,
+F<pod2usage> will just extract the "USAGE" section; some of
+the utilities will automatically call F<pod2usage> on themselves when
+you call them with C<-help>.
+
+=item L<podselect|podselect>
+
+F<pod2usage> is a special case of F<podselect>, a utility to extract
+named sections from documents written in POD. For instance, while
+utilities have "USAGE" sections, Perl modules usually have "SYNOPSIS"
+sections: C<podselect -s "SYNOPSIS" ...> will extract this section for
+a given file.
+
+=item L<podchecker|podchecker>
+
+If you're writing your own documentation in POD, the F<podchecker>
+utility will look for errors in your markup.
+
+=item L<splain|splain>
+
+F<splain> is an interface to L<perldiag> - paste in your error message
+to it, and it'll explain it for you.
+
+=item L<roffitall|roffitall>
+
+The C<roffitall> utility is not installed on your system but lives in
+the F<pod/> directory of your Perl source kit; it converts all the
+documentation from the distribution to F<*roff> format, and produces a
+typeset PostScript or text file of the whole lot.
+
+=back
+
+=head2 Convertors
+
+To help you convert legacy programs to Perl, we've included three
+conversion filters:
+
+=over 3
+
+=item L<a2p|a2p>
+
+F<a2p> converts F<awk> scripts to Perl programs; for example, C<a2p -F:>
+on the simple F<awk> script C<{print $2}> will produce a Perl program
+based around this code:
+
+ while (<>) {
+ ($Fld1,$Fld2) = split(/[:\n]/, $_, -1);
+ print $Fld2;
+ }
+
+=item L<s2p|s2p> and L<psed>
+
+Similarly, F<s2p> converts F<sed> scripts to Perl programs. F<s2p> run
+on C<s/foo/bar> will produce a Perl program based around this:
+
+ while (<>) {
+ chomp;
+ s/foo/bar/g;
+ print if $printit;
+ }
+
+When invoked as F<psed>, it behaves as a F<sed> implementation, written in
+Perl.
+
+=item L<find2perl|find2perl>
+
+Finally, F<find2perl> translates C<find> commands to Perl equivalents which
+use the L<File::Find|File::Find> module. As an example,
+C<find2perl . -user root -perm 4000 -print> produces the following callback
+subroutine for C<File::Find>:
+
+ sub wanted {
+ my ($dev,$ino,$mode,$nlink,$uid,$gid);
+ (($dev,$ino,$mode,$nlink,$uid,$gid) = lstat($_)) &&
+ $uid == $uid{'root'}) &&
+ (($mode & 0777) == 04000);
+ print("$name\n");
+ }
+
+=back
+
+As well as these filters for converting other languages, the
+L<pl2pm|pl2pm> utility will help you convert old-style Perl 4 libraries to
+new-style Perl5 modules.
+
+=head2 Administration
+
+=over 3
+
+=item L<config_data|config_data>
+
+Query or change configuration of Perl modules that use Module::Build-based
+configuration files for features and config data.
+
+=item L<libnetcfg|libnetcfg>
+
+To display and change the libnet configuration run the libnetcfg command.
+
+=item L<perlivp>
+
+The F<perlivp> program is set up at Perl source code build time to test
+the Perl version it was built under. It can be used after running C<make
+install> (or your platform's equivalent procedure) to verify that perl
+and its libraries have been installed correctly.
+
+=back
+
+=head2 Development
+
+There are a set of utilities which help you in developing Perl programs,
+and in particular, extending Perl with C.
+
+=over 3
+
+=item L<perlbug|perlbug>
+
+F<perlbug> is the recommended way to report bugs in the perl interpreter
+itself or any of the standard library modules back to the developers;
+please read through the documentation for F<perlbug> thoroughly before
+using it to submit a bug report.
+
+=item L<perlthanks|perlthanks>
+
+This program provides an easy way to send a thank-you message back to the
+authors and maintainers of perl. It's just F<perlbug> installed under
+another name.
+
+=item L<h2ph|h2ph>
+
+Back before Perl had the XS system for connecting with C libraries,
+programmers used to get library constants by reading through the C
+header files. You may still see C<require 'syscall.ph'> or similar
+around - the F<.ph> file should be created by running F<h2ph> on the
+corresponding F<.h> file. See the F<h2ph> documentation for more on how
+to convert a whole bunch of header files at once.
+
+=item L<c2ph|c2ph> and L<pstruct|pstruct>
+
+F<c2ph> and F<pstruct>, which are actually the same program but behave
+differently depending on how they are called, provide another way of
+getting at C with Perl - they'll convert C structures and union declarations
+to Perl code. This is deprecated in favour of F<h2xs> these days.
+
+=item L<h2xs|h2xs>
+
+F<h2xs> converts C header files into XS modules, and will try and write
+as much glue between C libraries and Perl modules as it can. It's also
+very useful for creating skeletons of pure Perl modules.
+
+=item L<enc2xs>
+
+F<enc2xs> builds a Perl extension for use by Encode from either
+Unicode Character Mapping files (.ucm) or Tcl Encoding Files (.enc).
+Besides being used internally during the build process of the Encode
+module, you can use F<enc2xs> to add your own encoding to perl.
+No knowledge of XS is necessary.
+
+=item L<xsubpp>
+
+F<xsubpp> is a compiler to convert Perl XS code into C code.
+It is typically run by the makefiles created by L<ExtUtils::MakeMaker>.
+
+F<xsubpp> will compile XS code into C code by embedding the constructs
+necessary to let C functions manipulate Perl values and creates the glue
+necessary to let Perl access those functions.
+
+=item L<dprofpp|dprofpp>
+
+Perl comes with a profiler, the F<Devel::DProf> module. The
+F<dprofpp> utility analyzes the output of this profiler and tells you
+which subroutines are taking up the most run time. See L<Devel::DProf>
+for more information.
+
+=item L<prove>
+
+F<prove> is a command-line interface to the test-running functionality
+of F<Test::Harness>. It's an alternative to C<make test>.
+
+=item L<corelist>
+
+A command-line front-end to C<Module::CoreList>, to query what modules
+were shipped with given versions of perl.
+
+=back
+
+=head2 General tools
+
+A few general-purpose tools are shipped with perl, mostly because they
+came along modules included in the perl distribution.
+
+=over 3
+
+=item L<piconv>
+
+B<piconv> is a Perl version of B<iconv>, a character encoding converter
+widely available for various Unixen today. This script was primarily a
+technology demonstrator for Perl 5.8.0, but you can use piconv in the
+place of iconv for virtually any case.
+
+=item L<ptar>
+
+F<ptar> is a tar-like program, written in pure Perl.
+
+=item L<ptardiff>
+
+F<ptardiff> is a small utility that produces a diff between an extracted
+archive and an unextracted one. (Note that this utility requires the
+C<Text::Diff> module to function properly; this module isn't distributed
+with perl, but is available from the CPAN.)
+
+=item L<shasum>
+
+This utility, that comes with the C<Digest::SHA> module, is used to print
+or verify SHA checksums.
+
+=back
+
+=head2 Installation
+
+These utilities help manage extra Perl modules that don't come with the perl
+distribution.
+
+=over 3
+
+=item L<cpan>
+
+F<cpan> is a command-line interface to CPAN.pm. It allows you to install
+modules or distributions from CPAN, or just get information about them, and
+a lot more. It is similar to the command line mode of the L<CPAN> module,
+
+ perl -MCPAN -e shell
+
+=item L<cpanp>
+
+F<cpanp> is, like F<cpan>, a command-line interface to the CPAN, using
+the C<CPANPLUS> module as a back-end. It can be used interactively or
+imperatively.
+
+=item L<cpan2dist>
+
+F<cpan2dist> is a tool to create distributions (or packages) from CPAN
+modules, then suitable for your package manager of choice. Support for
+specific formats are available from CPAN as C<CPANPLUS::Dist::*> modules.
+
+=item L<instmodsh>
+
+A little interface to ExtUtils::Installed to examine installed modules,
+validate your packlists and even create a tarball from an installed module.
+
+=back
+
+=head1 SEE ALSO
+
+L<perldoc|perldoc>, L<pod2man|pod2man>, L<perlpod>,
+L<pod2html|pod2html>, L<pod2usage|pod2usage>, L<podselect|podselect>,
+L<podchecker|podchecker>, L<splain|splain>, L<perldiag>,
+L<roffitall|roffitall>, L<a2p|a2p>, L<s2p|s2p>, L<find2perl|find2perl>,
+L<File::Find|File::Find>, L<pl2pm|pl2pm>, L<perlbug|perlbug>,
+L<h2ph|h2ph>, L<c2ph|c2ph>, L<h2xs|h2xs>, L<dprofpp|dprofpp>,
+L<Devel::DProf>, L<enc2xs>, L<xsubpp>, L<cpan>, L<cpanp>, L<cpan2dist>,
+L<instmodsh>, L<piconv>, L<prove>, L<corelist>, L<ptar>, L<ptardiff>,
+L<shasum>
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perluts.pod b/Master/tlpkg/tlperl/lib/pods/perluts.pod
new file mode 100644
index 00000000000..2025e37ef7a
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perluts.pod
@@ -0,0 +1,107 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see perlpod manpage) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perluts - Perl under UTS
+
+=head1 SYNOPSIS
+
+This document can be read I<as is>: as F<README.uts>, or you
+can read it after you build your package using "man perluts".
+
+The purpose is to help you build Perl for UTS, which, if you
+follow these instructions, should be easy, and result in
+a solidly working installation.
+
+=head1 DESCRIPTION
+
+Perl 5.7.2 (Developmental) or Perl 5.8.x (forthcoming) for UTS
+
+=head1 BUILDING PERL ON UTS
+
+NOTE: Some sites have redefined the way uname works, and if yours
+does this, special steps must be taken so that Configure can
+recognize your system as a UTS system. To see if you are in
+this category, issue the command "uname -a". It should look
+something like:
+
+ uts juno 4 4.4 9672 370
+
+At any rate, the first field should be "uts". If this is not
+the case; supposing it is, say telcoUTS, create a script, uts/uname
+(i.e. uname, in the subdirectory "uts" of the main Perl source dir):
+ # uname
+ /usr/bin/uname "$@" | sed -e 's/^telcoUTS/uts/'
+
+and when you execute Configure, do it as below, except for adding
+PATH=uts:$PATH as a prefix. I.e. do:
+
+ PATH=uts:$PATH ./Configure ...
+
+There is no need to do an interactive configure, just type
+
+ ./Configure -de [-Dusedevel] [-Doptimize=-g ] 2>&1 | tee Conf.out
+
+"-Dusedevel" may be required to configure Perl 5.7.2 non-interactively.
+Use -Doptimize=-g if you want to run Perl under sdb or gdb, OR
+if you want to be able to use the -D command line flags to perl,
+which are occasionally useful in debugging perl scripts.
+
+In this and the following steps, the "2>&1 | tee XXX.out" records all
+output from the process, which will be useful if anything unexpected
+goes wrong.
+
+Then do the compilation with
+
+ make 2>&1 | tee make.out
+
+Finally, test using
+
+ make test 2>&1 | tee make-test.out
+
+In the output, the only failures you should see should look like:
+
+ lib/Math/BigInt/t/bigfltpm.........Use of uninitialized value ...
+ FAILED at test 57
+ lib/Math/BigInt/t/bigintc..........ok
+ lib/Math/BigInt/t/bigintpm.........FAILED at test 204
+ lib/Math/BigInt/t/mbimbf...........Use of uninitialized value ...
+ Illegal division by zero at ../lib/Math/BigInt/Calc.pm line 314.
+ FAILED at test 71
+ lib/Math/Complex...................exp: OVERFLOW
+ FAILED at test 250
+ lib/Math/Trig......................exp: OVERFLOW
+ ok
+ lib/Memoize/t/array................ok
+ ...
+ lib/Net/protoent...................ok
+ lib/Net/servent....................FAILED at test 0
+
+This means that everything passes except for some problems in the
+packages "Math::BigInt", "Math::Complex", and "Math::Trig".
+The lib/Net/servent failure seems to be a bug in the test
+program. To confirm this, from the main Perl source dir, do:
+
+ LD_LIBRARY_PATH=`pwd` ./perl -Ilib lib/Net/servent.t
+
+and it should output
+
+ 1..3
+ ok 1
+ ok 2
+ ok 3
+
+=head1 Installing the built perl on UTS
+
+Run the command "make install"
+
+=head1 AUTHOR
+
+ Hal Morris
+ UTS Global LLC
+ email: hom00@utsglobal.com
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlvar.pod b/Master/tlpkg/tlperl/lib/pods/perlvar.pod
new file mode 100644
index 00000000000..bc04dcb9c55
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlvar.pod
@@ -0,0 +1,1780 @@
+=head1 NAME
+
+perlvar - Perl predefined variables
+
+=head1 DESCRIPTION
+
+=head2 Predefined Names
+
+The following names have special meaning to Perl. Most
+punctuation names have reasonable mnemonics, or analogs in the
+shells. Nevertheless, if you wish to use long variable names,
+you need only say
+
+ use English;
+
+at the top of your program. This aliases all the short names to the long
+names in the current package. Some even have medium names, generally
+borrowed from B<awk>. In general, it's best to use the
+
+ use English '-no_match_vars';
+
+invocation if you don't need $PREMATCH, $MATCH, or $POSTMATCH, as it avoids
+a certain performance hit with the use of regular expressions. See
+L<English>.
+
+Variables that depend on the currently selected filehandle may be set by
+calling an appropriate object method on the IO::Handle object, although
+this is less efficient than using the regular built-in variables. (Summary
+lines below for this contain the word HANDLE.) First you must say
+
+ use IO::Handle;
+
+after which you may use either
+
+ method HANDLE EXPR
+
+or more safely,
+
+ HANDLE->method(EXPR)
+
+Each method returns the old value of the IO::Handle attribute.
+The methods each take an optional EXPR, which, if supplied, specifies the
+new value for the IO::Handle attribute in question. If not supplied,
+most methods do nothing to the current value--except for
+autoflush(), which will assume a 1 for you, just to be different.
+
+Because loading in the IO::Handle class is an expensive operation, you should
+learn how to use the regular built-in variables.
+
+A few of these variables are considered "read-only". This means that if
+you try to assign to this variable, either directly or indirectly through
+a reference, you'll raise a run-time exception.
+
+You should be very careful when modifying the default values of most
+special variables described in this document. In most cases you want
+to localize these variables before changing them, since if you don't,
+the change may affect other modules which rely on the default values
+of the special variables that you have changed. This is one of the
+correct ways to read the whole file at once:
+
+ open my $fh, "<", "foo" or die $!;
+ local $/; # enable localized slurp mode
+ my $content = <$fh>;
+ close $fh;
+
+But the following code is quite bad:
+
+ open my $fh, "<", "foo" or die $!;
+ undef $/; # enable slurp mode
+ my $content = <$fh>;
+ close $fh;
+
+since some other module, may want to read data from some file in the
+default "line mode", so if the code we have just presented has been
+executed, the global value of C<$/> is now changed for any other code
+running inside the same Perl interpreter.
+
+Usually when a variable is localized you want to make sure that this
+change affects the shortest scope possible. So unless you are already
+inside some short C<{}> block, you should create one yourself. For
+example:
+
+ my $content = '';
+ open my $fh, "<", "foo" or die $!;
+ {
+ local $/;
+ $content = <$fh>;
+ }
+ close $fh;
+
+Here is an example of how your own code can go broken:
+
+ for (1..5){
+ nasty_break();
+ print "$_ ";
+ }
+ sub nasty_break {
+ $_ = 5;
+ # do something with $_
+ }
+
+You probably expect this code to print:
+
+ 1 2 3 4 5
+
+but instead you get:
+
+ 5 5 5 5 5
+
+Why? Because nasty_break() modifies C<$_> without localizing it
+first. The fix is to add local():
+
+ local $_ = 5;
+
+It's easy to notice the problem in such a short example, but in more
+complicated code you are looking for trouble if you don't localize
+changes to the special variables.
+
+The following list is ordered by scalar variables first, then the
+arrays, then the hashes.
+
+=over 8
+
+=item $ARG
+
+=item $_
+X<$_> X<$ARG>
+
+The default input and pattern-searching space. The following pairs are
+equivalent:
+
+ while (<>) {...} # equivalent only in while!
+ while (defined($_ = <>)) {...}
+
+ /^Subject:/
+ $_ =~ /^Subject:/
+
+ tr/a-z/A-Z/
+ $_ =~ tr/a-z/A-Z/
+
+ chomp
+ chomp($_)
+
+Here are the places where Perl will assume $_ even if you
+don't use it:
+
+=over 3
+
+=item *
+
+The following functions:
+
+abs, alarm, chomp, chop, chr, chroot, cos, defined, eval, exp, glob,
+hex, int, lc, lcfirst, length, log, lstat, mkdir, oct, ord, pos, print,
+quotemeta, readlink, readpipe, ref, require, reverse (in scalar context only),
+rmdir, sin, split (on its second argument), sqrt, stat, study, uc, ucfirst,
+unlink, unpack.
+
+=item *
+
+All file tests (C<-f>, C<-d>) except for C<-t>, which defaults to STDIN.
+See L<perlfunc/-X>
+
+
+=item *
+
+The pattern matching operations C<m//>, C<s///> and C<tr///> (aka C<y///>)
+when used without an C<=~> operator.
+
+=item *
+
+The default iterator variable in a C<foreach> loop if no other
+variable is supplied.
+
+=item *
+
+The implicit iterator variable in the grep() and map() functions.
+
+=item *
+
+The implicit variable of given().
+
+=item *
+
+The default place to put an input record when a C<< <FH> >>
+operation's result is tested by itself as the sole criterion of a C<while>
+test. Outside a C<while> test, this will not happen.
+
+=back
+
+As C<$_> is a global variable, this may lead in some cases to unwanted
+side-effects. As of perl 5.9.1, you can now use a lexical version of
+C<$_> by declaring it in a file or in a block with C<my>. Moreover,
+declaring C<our $_> restores the global C<$_> in the current scope.
+
+(Mnemonic: underline is understood in certain operations.)
+
+=back
+
+=over 8
+
+=item $a
+
+=item $b
+X<$a> X<$b>
+
+Special package variables when using sort(), see L<perlfunc/sort>.
+Because of this specialness $a and $b don't need to be declared
+(using use vars, or our()) even when using the C<strict 'vars'> pragma.
+Don't lexicalize them with C<my $a> or C<my $b> if you want to be
+able to use them in the sort() comparison block or function.
+
+=back
+
+=over 8
+
+=item $<I<digits>> ($1, $2, ...)
+X<$1> X<$2> X<$3>
+
+Contains the subpattern from the corresponding set of capturing
+parentheses from the last successful pattern match, not counting patterns
+matched in nested blocks that have been exited already. (Mnemonic:
+like \digits.) These variables are all read-only and dynamically
+scoped to the current BLOCK.
+
+=item $MATCH
+
+=item $&
+X<$&> X<$MATCH>
+
+The string matched by the last successful pattern match (not counting
+any matches hidden within a BLOCK or eval() enclosed by the current
+BLOCK). (Mnemonic: like & in some editors.) This variable is read-only
+and dynamically scoped to the current BLOCK.
+
+The use of this variable anywhere in a program imposes a considerable
+performance penalty on all regular expression matches. See L</BUGS>.
+
+See L</@-> for a replacement.
+
+=item ${^MATCH}
+X<${^MATCH}>
+
+This is similar to C<$&> (C<$MATCH>) except that it does not incur the
+performance penalty associated with that variable, and is only guaranteed
+to return a defined value when the pattern was compiled or executed with
+the C</p> modifier.
+
+=item $PREMATCH
+
+=item $`
+X<$`> X<$PREMATCH>
+
+The string preceding whatever was matched by the last successful
+pattern match (not counting any matches hidden within a BLOCK or eval
+enclosed by the current BLOCK). (Mnemonic: C<`> often precedes a quoted
+string.) This variable is read-only.
+
+The use of this variable anywhere in a program imposes a considerable
+performance penalty on all regular expression matches. See L</BUGS>.
+
+See L</@-> for a replacement.
+
+=item ${^PREMATCH}
+X<${^PREMATCH}>
+
+This is similar to C<$`> ($PREMATCH) except that it does not incur the
+performance penalty associated with that variable, and is only guaranteed
+to return a defined value when the pattern was compiled or executed with
+the C</p> modifier.
+
+=item $POSTMATCH
+
+=item $'
+X<$'> X<$POSTMATCH>
+
+The string following whatever was matched by the last successful
+pattern match (not counting any matches hidden within a BLOCK or eval()
+enclosed by the current BLOCK). (Mnemonic: C<'> often follows a quoted
+string.) Example:
+
+ local $_ = 'abcdefghi';
+ /def/;
+ print "$`:$&:$'\n"; # prints abc:def:ghi
+
+This variable is read-only and dynamically scoped to the current BLOCK.
+
+The use of this variable anywhere in a program imposes a considerable
+performance penalty on all regular expression matches. See L</BUGS>.
+
+See L</@-> for a replacement.
+
+=item ${^POSTMATCH}
+X<${^POSTMATCH}>
+
+This is similar to C<$'> (C<$POSTMATCH>) except that it does not incur the
+performance penalty associated with that variable, and is only guaranteed
+to return a defined value when the pattern was compiled or executed with
+the C</p> modifier.
+
+=item $LAST_PAREN_MATCH
+
+=item $+
+X<$+> X<$LAST_PAREN_MATCH>
+
+The text matched by the last bracket of the last successful search pattern.
+This is useful if you don't know which one of a set of alternative patterns
+matched. For example:
+
+ /Version: (.*)|Revision: (.*)/ && ($rev = $+);
+
+(Mnemonic: be positive and forward looking.)
+This variable is read-only and dynamically scoped to the current BLOCK.
+
+=item $LAST_SUBMATCH_RESULT
+
+=item $^N
+X<$^N>
+
+The text matched by the used group most-recently closed (i.e. the group
+with the rightmost closing parenthesis) of the last successful search
+pattern. (Mnemonic: the (possibly) Nested parenthesis that most
+recently closed.)
+
+This is primarily used inside C<(?{...})> blocks for examining text
+recently matched. For example, to effectively capture text to a variable
+(in addition to C<$1>, C<$2>, etc.), replace C<(...)> with
+
+ (?:(...)(?{ $var = $^N }))
+
+By setting and then using C<$var> in this way relieves you from having to
+worry about exactly which numbered set of parentheses they are.
+
+This variable is dynamically scoped to the current BLOCK.
+
+=item @LAST_MATCH_END
+
+=item @+
+X<@+> X<@LAST_MATCH_END>
+
+This array holds the offsets of the ends of the last successful
+submatches in the currently active dynamic scope. C<$+[0]> is
+the offset into the string of the end of the entire match. This
+is the same value as what the C<pos> function returns when called
+on the variable that was matched against. The I<n>th element
+of this array holds the offset of the I<n>th submatch, so
+C<$+[1]> is the offset past where $1 ends, C<$+[2]> the offset
+past where $2 ends, and so on. You can use C<$#+> to determine
+how many subgroups were in the last successful match. See the
+examples given for the C<@-> variable.
+
+=item %LAST_PAREN_MATCH
+
+=item %+
+X<%+>
+
+Similar to C<@+>, the C<%+> hash allows access to the named capture
+buffers, should they exist, in the last successful match in the
+currently active dynamic scope.
+
+For example, C<$+{foo}> is equivalent to C<$1> after the following match:
+
+ 'foo' =~ /(?<foo>foo)/;
+
+The keys of the C<%+> hash list only the names of buffers that have
+captured (and that are thus associated to defined values).
+
+The underlying behaviour of C<%+> is provided by the
+L<Tie::Hash::NamedCapture> module.
+
+B<Note:> C<%-> and C<%+> are tied views into a common internal hash
+associated with the last successful regular expression. Therefore mixing
+iterative access to them via C<each> may have unpredictable results.
+Likewise, if the last successful match changes, then the results may be
+surprising.
+
+=item HANDLE->input_line_number(EXPR)
+
+=item $INPUT_LINE_NUMBER
+
+=item $NR
+
+=item $.
+X<$.> X<$NR> X<$INPUT_LINE_NUMBER> X<line number>
+
+Current line number for the last filehandle accessed.
+
+Each filehandle in Perl counts the number of lines that have been read
+from it. (Depending on the value of C<$/>, Perl's idea of what
+constitutes a line may not match yours.) When a line is read from a
+filehandle (via readline() or C<< <> >>), or when tell() or seek() is
+called on it, C<$.> becomes an alias to the line counter for that
+filehandle.
+
+You can adjust the counter by assigning to C<$.>, but this will not
+actually move the seek pointer. I<Localizing C<$.> will not localize
+the filehandle's line count>. Instead, it will localize perl's notion
+of which filehandle C<$.> is currently aliased to.
+
+C<$.> is reset when the filehandle is closed, but B<not> when an open
+filehandle is reopened without an intervening close(). For more
+details, see L<perlop/"IE<sol>O Operators">. Because C<< <> >> never does
+an explicit close, line numbers increase across ARGV files (but see
+examples in L<perlfunc/eof>).
+
+You can also use C<< HANDLE->input_line_number(EXPR) >> to access the
+line counter for a given filehandle without having to worry about
+which handle you last accessed.
+
+(Mnemonic: many programs use "." to mean the current line number.)
+
+=item IO::Handle->input_record_separator(EXPR)
+
+=item $INPUT_RECORD_SEPARATOR
+
+=item $RS
+
+=item $/
+X<$/> X<$RS> X<$INPUT_RECORD_SEPARATOR>
+
+The input record separator, newline by default. This
+influences Perl's idea of what a "line" is. Works like B<awk>'s RS
+variable, including treating empty lines as a terminator if set to
+the null string. (An empty line cannot contain any spaces
+or tabs.) You may set it to a multi-character string to match a
+multi-character terminator, or to C<undef> to read through the end
+of file. Setting it to C<"\n\n"> means something slightly
+different than setting to C<"">, if the file contains consecutive
+empty lines. Setting to C<""> will treat two or more consecutive
+empty lines as a single empty line. Setting to C<"\n\n"> will
+blindly assume that the next input character belongs to the next
+paragraph, even if it's a newline. (Mnemonic: / delimits
+line boundaries when quoting poetry.)
+
+ local $/; # enable "slurp" mode
+ local $_ = <FH>; # whole file now here
+ s/\n[ \t]+/ /g;
+
+Remember: the value of C<$/> is a string, not a regex. B<awk> has to be
+better for something. :-)
+
+Setting C<$/> to a reference to an integer, scalar containing an integer, or
+scalar that's convertible to an integer will attempt to read records
+instead of lines, with the maximum record size being the referenced
+integer. So this:
+
+ local $/ = \32768; # or \"32768", or \$var_containing_32768
+ open my $fh, "<", $myfile or die $!;
+ local $_ = <$fh>;
+
+will read a record of no more than 32768 bytes from FILE. If you're
+not reading from a record-oriented file (or your OS doesn't have
+record-oriented files), then you'll likely get a full chunk of data
+with every read. If a record is larger than the record size you've
+set, you'll get the record back in pieces. Trying to set the record
+size to zero or less will cause reading in the (rest of the) whole file.
+
+On VMS, record reads are done with the equivalent of C<sysread>,
+so it's best not to mix record and non-record reads on the same
+file. (This is unlikely to be a problem, because any file you'd
+want to read in record mode is probably unusable in line mode.)
+Non-VMS systems do normal I/O, so it's safe to mix record and
+non-record reads of a file.
+
+See also L<perlport/"Newlines">. Also see C<$.>.
+
+=item HANDLE->autoflush(EXPR)
+
+=item $OUTPUT_AUTOFLUSH
+
+=item $|
+X<$|> X<autoflush> X<flush> X<$OUTPUT_AUTOFLUSH>
+
+If set to nonzero, forces a flush right away and after every write
+or print on the currently selected output channel. Default is 0
+(regardless of whether the channel is really buffered by the
+system or not; C<$|> tells you only whether you've asked Perl
+explicitly to flush after each write). STDOUT will
+typically be line buffered if output is to the terminal and block
+buffered otherwise. Setting this variable is useful primarily when
+you are outputting to a pipe or socket, such as when you are running
+a Perl program under B<rsh> and want to see the output as it's
+happening. This has no effect on input buffering. See L<perlfunc/getc>
+for that. See L<perldoc/select> on how to select the output channel.
+See also L<IO::Handle>. (Mnemonic: when you want your pipes to be piping hot.)
+
+=item IO::Handle->output_field_separator EXPR
+
+=item $OUTPUT_FIELD_SEPARATOR
+
+=item $OFS
+
+=item $,
+X<$,> X<$OFS> X<$OUTPUT_FIELD_SEPARATOR>
+
+The output field separator for the print operator. If defined, this
+value is printed between each of print's arguments. Default is C<undef>.
+(Mnemonic: what is printed when there is a "," in your print statement.)
+
+=item IO::Handle->output_record_separator EXPR
+
+=item $OUTPUT_RECORD_SEPARATOR
+
+=item $ORS
+
+=item $\
+X<$\> X<$ORS> X<$OUTPUT_RECORD_SEPARATOR>
+
+The output record separator for the print operator. If defined, this
+value is printed after the last of print's arguments. Default is C<undef>.
+(Mnemonic: you set C<$\> instead of adding "\n" at the end of the print.
+Also, it's just like C<$/>, but it's what you get "back" from Perl.)
+
+=item $LIST_SEPARATOR
+
+=item $"
+X<$"> X<$LIST_SEPARATOR>
+
+This is like C<$,> except that it applies to array and slice values
+interpolated into a double-quoted string (or similar interpreted
+string). Default is a space. (Mnemonic: obvious, I think.)
+
+=item $SUBSCRIPT_SEPARATOR
+
+=item $SUBSEP
+
+=item $;
+X<$;> X<$SUBSEP> X<SUBSCRIPT_SEPARATOR>
+
+The subscript separator for multidimensional array emulation. If you
+refer to a hash element as
+
+ $foo{$a,$b,$c}
+
+it really means
+
+ $foo{join($;, $a, $b, $c)}
+
+But don't put
+
+ @foo{$a,$b,$c} # a slice--note the @
+
+which means
+
+ ($foo{$a},$foo{$b},$foo{$c})
+
+Default is "\034", the same as SUBSEP in B<awk>. If your
+keys contain binary data there might not be any safe value for C<$;>.
+(Mnemonic: comma (the syntactic subscript separator) is a
+semi-semicolon. Yeah, I know, it's pretty lame, but C<$,> is already
+taken for something more important.)
+
+Consider using "real" multidimensional arrays as described
+in L<perllol>.
+
+=item HANDLE->format_page_number(EXPR)
+
+=item $FORMAT_PAGE_NUMBER
+
+=item $%
+X<$%> X<$FORMAT_PAGE_NUMBER>
+
+The current page number of the currently selected output channel.
+Used with formats.
+(Mnemonic: % is page number in B<nroff>.)
+
+=item HANDLE->format_lines_per_page(EXPR)
+
+=item $FORMAT_LINES_PER_PAGE
+
+=item $=
+X<$=> X<$FORMAT_LINES_PER_PAGE>
+
+The current page length (printable lines) of the currently selected
+output channel. Default is 60.
+Used with formats.
+(Mnemonic: = has horizontal lines.)
+
+=item HANDLE->format_lines_left(EXPR)
+
+=item $FORMAT_LINES_LEFT
+
+=item $-
+X<$-> X<$FORMAT_LINES_LEFT>
+
+The number of lines left on the page of the currently selected output
+channel.
+Used with formats.
+(Mnemonic: lines_on_page - lines_printed.)
+
+=item @LAST_MATCH_START
+
+=item @-
+X<@-> X<@LAST_MATCH_START>
+
+$-[0] is the offset of the start of the last successful match.
+C<$-[>I<n>C<]> is the offset of the start of the substring matched by
+I<n>-th subpattern, or undef if the subpattern did not match.
+
+Thus after a match against $_, $& coincides with C<substr $_, $-[0],
+$+[0] - $-[0]>. Similarly, $I<n> coincides with C<substr $_, $-[n],
+$+[n] - $-[n]> if C<$-[n]> is defined, and $+ coincides with
+C<substr $_, $-[$#-], $+[$#-] - $-[$#-]>. One can use C<$#-> to find the last
+matched subgroup in the last successful match. Contrast with
+C<$#+>, the number of subgroups in the regular expression. Compare
+with C<@+>.
+
+This array holds the offsets of the beginnings of the last
+successful submatches in the currently active dynamic scope.
+C<$-[0]> is the offset into the string of the beginning of the
+entire match. The I<n>th element of this array holds the offset
+of the I<n>th submatch, so C<$-[1]> is the offset where $1
+begins, C<$-[2]> the offset where $2 begins, and so on.
+
+After a match against some variable $var:
+
+=over 5
+
+=item C<$`> is the same as C<substr($var, 0, $-[0])>
+
+=item C<$&> is the same as C<substr($var, $-[0], $+[0] - $-[0])>
+
+=item C<$'> is the same as C<substr($var, $+[0])>
+
+=item C<$1> is the same as C<substr($var, $-[1], $+[1] - $-[1])>
+
+=item C<$2> is the same as C<substr($var, $-[2], $+[2] - $-[2])>
+
+=item C<$3> is the same as C<substr($var, $-[3], $+[3] - $-[3])>
+
+=back
+
+=item %-
+X<%->
+
+Similar to C<%+>, this variable allows access to the named capture buffers
+in the last successful match in the currently active dynamic scope. To
+each capture buffer name found in the regular expression, it associates a
+reference to an array containing the list of values captured by all
+buffers with that name (should there be several of them), in the order
+where they appear.
+
+Here's an example:
+
+ if ('1234' =~ /(?<A>1)(?<B>2)(?<A>3)(?<B>4)/) {
+ foreach my $bufname (sort keys %-) {
+ my $ary = $-{$bufname};
+ foreach my $idx (0..$#$ary) {
+ print "\$-{$bufname}[$idx] : ",
+ (defined($ary->[$idx]) ? "'$ary->[$idx]'" : "undef"),
+ "\n";
+ }
+ }
+ }
+
+would print out:
+
+ $-{A}[0] : '1'
+ $-{A}[1] : '3'
+ $-{B}[0] : '2'
+ $-{B}[1] : '4'
+
+The keys of the C<%-> hash correspond to all buffer names found in
+the regular expression.
+
+The behaviour of C<%-> is implemented via the
+L<Tie::Hash::NamedCapture> module.
+
+B<Note:> C<%-> and C<%+> are tied views into a common internal hash
+associated with the last successful regular expression. Therefore mixing
+iterative access to them via C<each> may have unpredictable results.
+Likewise, if the last successful match changes, then the results may be
+surprising.
+
+=item HANDLE->format_name(EXPR)
+
+=item $FORMAT_NAME
+
+=item $~
+X<$~> X<$FORMAT_NAME>
+
+The name of the current report format for the currently selected output
+channel. Default is the name of the filehandle. (Mnemonic: brother to
+C<$^>.)
+
+=item HANDLE->format_top_name(EXPR)
+
+=item $FORMAT_TOP_NAME
+
+=item $^
+X<$^> X<$FORMAT_TOP_NAME>
+
+The name of the current top-of-page format for the currently selected
+output channel. Default is the name of the filehandle with _TOP
+appended. (Mnemonic: points to top of page.)
+
+=item IO::Handle->format_line_break_characters EXPR
+
+=item $FORMAT_LINE_BREAK_CHARACTERS
+
+=item $:
+X<$:> X<FORMAT_LINE_BREAK_CHARACTERS>
+
+The current set of characters after which a string may be broken to
+fill continuation fields (starting with ^) in a format. Default is
+S<" \n-">, to break on whitespace or hyphens. (Mnemonic: a "colon" in
+poetry is a part of a line.)
+
+=item IO::Handle->format_formfeed EXPR
+
+=item $FORMAT_FORMFEED
+
+=item $^L
+X<$^L> X<$FORMAT_FORMFEED>
+
+What formats output as a form feed. Default is \f.
+
+=item $ACCUMULATOR
+
+=item $^A
+X<$^A> X<$ACCUMULATOR>
+
+The current value of the write() accumulator for format() lines. A format
+contains formline() calls that put their result into C<$^A>. After
+calling its format, write() prints out the contents of C<$^A> and empties.
+So you never really see the contents of C<$^A> unless you call
+formline() yourself and then look at it. See L<perlform> and
+L<perlfunc/formline()>.
+
+=item $CHILD_ERROR
+
+=item $?
+X<$?> X<$CHILD_ERROR>
+
+The status returned by the last pipe close, backtick (C<``>) command,
+successful call to wait() or waitpid(), or from the system()
+operator. This is just the 16-bit status word returned by the
+traditional Unix wait() system call (or else is made up to look like it). Thus, the
+exit value of the subprocess is really (C<<< $? >> 8 >>>), and
+C<$? & 127> gives which signal, if any, the process died from, and
+C<$? & 128> reports whether there was a core dump. (Mnemonic:
+similar to B<sh> and B<ksh>.)
+
+Additionally, if the C<h_errno> variable is supported in C, its value
+is returned via $? if any C<gethost*()> function fails.
+
+If you have installed a signal handler for C<SIGCHLD>, the
+value of C<$?> will usually be wrong outside that handler.
+
+Inside an C<END> subroutine C<$?> contains the value that is going to be
+given to C<exit()>. You can modify C<$?> in an C<END> subroutine to
+change the exit status of your program. For example:
+
+ END {
+ $? = 1 if $? == 255; # die would make it 255
+ }
+
+Under VMS, the pragma C<use vmsish 'status'> makes C<$?> reflect the
+actual VMS exit status, instead of the default emulation of POSIX
+status; see L<perlvms/$?> for details.
+
+Also see L<Error Indicators>.
+
+=item ${^CHILD_ERROR_NATIVE}
+X<$^CHILD_ERROR_NATIVE>
+
+The native status returned by the last pipe close, backtick (C<``>)
+command, successful call to wait() or waitpid(), or from the system()
+operator. On POSIX-like systems this value can be decoded with the
+WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WIFSTOPPED, WSTOPSIG
+and WIFCONTINUED functions provided by the L<POSIX> module.
+
+Under VMS this reflects the actual VMS exit status; i.e. it is the same
+as $? when the pragma C<use vmsish 'status'> is in effect.
+
+=item ${^ENCODING}
+X<$^ENCODING>
+
+The I<object reference> to the Encode object that is used to convert
+the source code to Unicode. Thanks to this variable your perl script
+does not have to be written in UTF-8. Default is I<undef>. The direct
+manipulation of this variable is highly discouraged.
+
+=item $OS_ERROR
+
+=item $ERRNO
+
+=item $!
+X<$!> X<$ERRNO> X<$OS_ERROR>
+
+If used numerically, yields the current value of the C C<errno>
+variable, or in other words, if a system or library call fails, it
+sets this variable. This means that the value of C<$!> is meaningful
+only I<immediately> after a B<failure>:
+
+ if (open my $fh, "<", $filename) {
+ # Here $! is meaningless.
+ ...
+ } else {
+ # ONLY here is $! meaningful.
+ ...
+ # Already here $! might be meaningless.
+ }
+ # Since here we might have either success or failure,
+ # here $! is meaningless.
+
+In the above I<meaningless> stands for anything: zero, non-zero,
+C<undef>. A successful system or library call does B<not> set
+the variable to zero.
+
+If used as a string, yields the corresponding system error string.
+You can assign a number to C<$!> to set I<errno> if, for instance,
+you want C<"$!"> to return the string for error I<n>, or you want
+to set the exit value for the die() operator. (Mnemonic: What just
+went bang?)
+
+Also see L<Error Indicators>.
+
+=item %OS_ERROR
+
+=item %ERRNO
+
+=item %!
+X<%!>
+
+Each element of C<%!> has a true value only if C<$!> is set to that
+value. For example, C<$!{ENOENT}> is true if and only if the current
+value of C<$!> is C<ENOENT>; that is, if the most recent error was
+"No such file or directory" (or its moral equivalent: not all operating
+systems give that exact error, and certainly not all languages).
+To check if a particular key is meaningful on your system, use
+C<exists $!{the_key}>; for a list of legal keys, use C<keys %!>.
+See L<Errno> for more information, and also see above for the
+validity of C<$!>.
+
+=item $EXTENDED_OS_ERROR
+
+=item $^E
+X<$^E> X<$EXTENDED_OS_ERROR>
+
+Error information specific to the current operating system. At
+the moment, this differs from C<$!> under only VMS, OS/2, and Win32
+(and for MacPerl). On all other platforms, C<$^E> is always just
+the same as C<$!>.
+
+Under VMS, C<$^E> provides the VMS status value from the last
+system error. This is more specific information about the last
+system error than that provided by C<$!>. This is particularly
+important when C<$!> is set to B<EVMSERR>.
+
+Under OS/2, C<$^E> is set to the error code of the last call to
+OS/2 API either via CRT, or directly from perl.
+
+Under Win32, C<$^E> always returns the last error information
+reported by the Win32 call C<GetLastError()> which describes
+the last error from within the Win32 API. Most Win32-specific
+code will report errors via C<$^E>. ANSI C and Unix-like calls
+set C<errno> and so most portable Perl code will report errors
+via C<$!>.
+
+Caveats mentioned in the description of C<$!> generally apply to
+C<$^E>, also. (Mnemonic: Extra error explanation.)
+
+Also see L<Error Indicators>.
+
+=item $EVAL_ERROR
+
+=item $@
+X<$@> X<$EVAL_ERROR>
+
+The Perl syntax error message from the last eval() operator.
+If $@ is the null string, the last eval() parsed and executed
+correctly (although the operations you invoked may have failed in the
+normal fashion). (Mnemonic: Where was the syntax error "at"?)
+
+Warning messages are not collected in this variable. You can,
+however, set up a routine to process warnings by setting C<$SIG{__WARN__}>
+as described below.
+
+Also see L<Error Indicators>.
+
+=item $PROCESS_ID
+
+=item $PID
+
+=item $$
+X<$$> X<$PID> X<$PROCESS_ID>
+
+The process number of the Perl running this script. You should
+consider this variable read-only, although it will be altered
+across fork() calls. (Mnemonic: same as shells.)
+
+Note for Linux users: on Linux, the C functions C<getpid()> and
+C<getppid()> return different values from different threads. In order to
+be portable, this behavior is not reflected by C<$$>, whose value remains
+consistent across threads. If you want to call the underlying C<getpid()>,
+you may use the CPAN module C<Linux::Pid>.
+
+=item $REAL_USER_ID
+
+=item $UID
+
+=item $<
+X<< $< >> X<$UID> X<$REAL_USER_ID>
+
+The real uid of this process. (Mnemonic: it's the uid you came I<from>,
+if you're running setuid.) You can change both the real uid and
+the effective uid at the same time by using POSIX::setuid(). Since
+changes to $< require a system call, check $! after a change attempt to
+detect any possible errors.
+
+=item $EFFECTIVE_USER_ID
+
+=item $EUID
+
+=item $>
+X<< $> >> X<$EUID> X<$EFFECTIVE_USER_ID>
+
+The effective uid of this process. Example:
+
+ $< = $>; # set real to effective uid
+ ($<,$>) = ($>,$<); # swap real and effective uid
+
+You can change both the effective uid and the real uid at the same
+time by using POSIX::setuid(). Changes to $> require a check to $!
+to detect any possible errors after an attempted change.
+
+(Mnemonic: it's the uid you went I<to>, if you're running setuid.)
+C<< $< >> and C<< $> >> can be swapped only on machines
+supporting setreuid().
+
+=item $REAL_GROUP_ID
+
+=item $GID
+
+=item $(
+X<$(> X<$GID> X<$REAL_GROUP_ID>
+
+The real gid of this process. If you are on a machine that supports
+membership in multiple groups simultaneously, gives a space separated
+list of groups you are in. The first number is the one returned by
+getgid(), and the subsequent ones by getgroups(), one of which may be
+the same as the first number.
+
+However, a value assigned to C<$(> must be a single number used to
+set the real gid. So the value given by C<$(> should I<not> be assigned
+back to C<$(> without being forced numeric, such as by adding zero. Note
+that this is different to the effective gid (C<$)>) which does take a
+list.
+
+You can change both the real gid and the effective gid at the same
+time by using POSIX::setgid(). Changes to $( require a check to $!
+to detect any possible errors after an attempted change.
+
+(Mnemonic: parentheses are used to I<group> things. The real gid is the
+group you I<left>, if you're running setgid.)
+
+=item $EFFECTIVE_GROUP_ID
+
+=item $EGID
+
+=item $)
+X<$)> X<$EGID> X<$EFFECTIVE_GROUP_ID>
+
+The effective gid of this process. If you are on a machine that
+supports membership in multiple groups simultaneously, gives a space
+separated list of groups you are in. The first number is the one
+returned by getegid(), and the subsequent ones by getgroups(), one of
+which may be the same as the first number.
+
+Similarly, a value assigned to C<$)> must also be a space-separated
+list of numbers. The first number sets the effective gid, and
+the rest (if any) are passed to setgroups(). To get the effect of an
+empty list for setgroups(), just repeat the new effective gid; that is,
+to force an effective gid of 5 and an effectively empty setgroups()
+list, say C< $) = "5 5" >.
+
+You can change both the effective gid and the real gid at the same
+time by using POSIX::setgid() (use only a single numeric argument).
+Changes to $) require a check to $! to detect any possible errors
+after an attempted change.
+
+(Mnemonic: parentheses are used to I<group> things. The effective gid
+is the group that's I<right> for you, if you're running setgid.)
+
+C<< $< >>, C<< $> >>, C<$(> and C<$)> can be set only on
+machines that support the corresponding I<set[re][ug]id()> routine. C<$(>
+and C<$)> can be swapped only on machines supporting setregid().
+
+=item $PROGRAM_NAME
+
+=item $0
+X<$0> X<$PROGRAM_NAME>
+
+Contains the name of the program being executed.
+
+On some (read: not all) operating systems assigning to C<$0> modifies
+the argument area that the C<ps> program sees. On some platforms you
+may have to use special C<ps> options or a different C<ps> to see the
+changes. Modifying the $0 is more useful as a way of indicating the
+current program state than it is for hiding the program you're
+running. (Mnemonic: same as B<sh> and B<ksh>.)
+
+Note that there are platform specific limitations on the maximum
+length of C<$0>. In the most extreme case it may be limited to the
+space occupied by the original C<$0>.
+
+In some platforms there may be arbitrary amount of padding, for
+example space characters, after the modified name as shown by C<ps>.
+In some platforms this padding may extend all the way to the original
+length of the argument area, no matter what you do (this is the case
+for example with Linux 2.2).
+
+Note for BSD users: setting C<$0> does not completely remove "perl"
+from the ps(1) output. For example, setting C<$0> to C<"foobar"> may
+result in C<"perl: foobar (perl)"> (whether both the C<"perl: "> prefix
+and the " (perl)" suffix are shown depends on your exact BSD variant
+and version). This is an operating system feature, Perl cannot help it.
+
+In multithreaded scripts Perl coordinates the threads so that any
+thread may modify its copy of the C<$0> and the change becomes visible
+to ps(1) (assuming the operating system plays along). Note that
+the view of C<$0> the other threads have will not change since they
+have their own copies of it.
+
+If the program has been given to perl via the switches C<-e> or C<-E>,
+C<$0> will contain the string C<"-e">.
+
+=item $[
+X<$[>
+
+The index of the first element in an array, and of the first character
+in a substring. Default is 0, but you could theoretically set it
+to 1 to make Perl behave more like B<awk> (or Fortran) when
+subscripting and when evaluating the index() and substr() functions.
+(Mnemonic: [ begins subscripts.)
+
+As of release 5 of Perl, assignment to C<$[> is treated as a compiler
+directive, and cannot influence the behavior of any other file.
+(That's why you can only assign compile-time constants to it.) Its
+use is deprecated, and by default will trigger a warning.
+
+Note that, unlike other compile-time directives (such as L<strict>),
+assignment to C<$[> can be seen from outer lexical scopes in the same file.
+However, you can use local() on it to strictly bind its value to a
+lexical block.
+
+=item $]
+X<$]>
+
+The version + patchlevel / 1000 of the Perl interpreter. This variable
+can be used to determine whether the Perl interpreter executing a
+script is in the right range of versions. (Mnemonic: Is this version
+of perl in the right bracket?) Example:
+
+ warn "No checksumming!\n" if $] < 3.019;
+
+See also the documentation of C<use VERSION> and C<require VERSION>
+for a convenient way to fail if the running Perl interpreter is too old.
+
+The floating point representation can sometimes lead to inaccurate
+numeric comparisons. See C<$^V> for a more modern representation of
+the Perl version that allows accurate string comparisons.
+
+=item $COMPILING
+
+=item $^C
+X<$^C> X<$COMPILING>
+
+The current value of the flag associated with the B<-c> switch.
+Mainly of use with B<-MO=...> to allow code to alter its behavior
+when being compiled, such as for example to AUTOLOAD at compile
+time rather than normal, deferred loading. Setting
+C<$^C = 1> is similar to calling C<B::minus_c>.
+
+=item $DEBUGGING
+
+=item $^D
+X<$^D> X<$DEBUGGING>
+
+The current value of the debugging flags. (Mnemonic: value of B<-D>
+switch.) May be read or set. Like its command-line equivalent, you can use
+numeric or symbolic values, eg C<$^D = 10> or C<$^D = "st">.
+
+=item ${^RE_DEBUG_FLAGS}
+
+The current value of the regex debugging flags. Set to 0 for no debug output
+even when the re 'debug' module is loaded. See L<re> for details.
+
+=item ${^RE_TRIE_MAXBUF}
+
+Controls how certain regex optimisations are applied and how much memory they
+utilize. This value by default is 65536 which corresponds to a 512kB temporary
+cache. Set this to a higher value to trade memory for speed when matching
+large alternations. Set it to a lower value if you want the optimisations to
+be as conservative of memory as possible but still occur, and set it to a
+negative value to prevent the optimisation and conserve the most memory.
+Under normal situations this variable should be of no interest to you.
+
+=item $SYSTEM_FD_MAX
+
+=item $^F
+X<$^F> X<$SYSTEM_FD_MAX>
+
+The maximum system file descriptor, ordinarily 2. System file
+descriptors are passed to exec()ed processes, while higher file
+descriptors are not. Also, during an open(), system file descriptors are
+preserved even if the open() fails. (Ordinary file descriptors are
+closed before the open() is attempted.) The close-on-exec
+status of a file descriptor will be decided according to the value of
+C<$^F> when the corresponding file, pipe, or socket was opened, not the
+time of the exec().
+
+=item $^H
+
+WARNING: This variable is strictly for internal use only. Its availability,
+behavior, and contents are subject to change without notice.
+
+This variable contains compile-time hints for the Perl interpreter. At the
+end of compilation of a BLOCK the value of this variable is restored to the
+value when the interpreter started to compile the BLOCK.
+
+When perl begins to parse any block construct that provides a lexical scope
+(e.g., eval body, required file, subroutine body, loop body, or conditional
+block), the existing value of $^H is saved, but its value is left unchanged.
+When the compilation of the block is completed, it regains the saved value.
+Between the points where its value is saved and restored, code that
+executes within BEGIN blocks is free to change the value of $^H.
+
+This behavior provides the semantic of lexical scoping, and is used in,
+for instance, the C<use strict> pragma.
+
+The contents should be an integer; different bits of it are used for
+different pragmatic flags. Here's an example:
+
+ sub add_100 { $^H |= 0x100 }
+
+ sub foo {
+ BEGIN { add_100() }
+ bar->baz($boon);
+ }
+
+Consider what happens during execution of the BEGIN block. At this point
+the BEGIN block has already been compiled, but the body of foo() is still
+being compiled. The new value of $^H will therefore be visible only while
+the body of foo() is being compiled.
+
+Substitution of the above BEGIN block with:
+
+ BEGIN { require strict; strict->import('vars') }
+
+demonstrates how C<use strict 'vars'> is implemented. Here's a conditional
+version of the same lexical pragma:
+
+ BEGIN { require strict; strict->import('vars') if $condition }
+
+=item %^H
+
+The %^H hash provides the same scoping semantic as $^H. This makes it
+useful for implementation of lexically scoped pragmas. See L<perlpragma>.
+
+=item $INPLACE_EDIT
+
+=item $^I
+X<$^I> X<$INPLACE_EDIT>
+
+The current value of the inplace-edit extension. Use C<undef> to disable
+inplace editing. (Mnemonic: value of B<-i> switch.)
+
+=item $^M
+X<$^M>
+
+By default, running out of memory is an untrappable, fatal error.
+However, if suitably built, Perl can use the contents of C<$^M>
+as an emergency memory pool after die()ing. Suppose that your Perl
+were compiled with C<-DPERL_EMERGENCY_SBRK> and used Perl's malloc.
+Then
+
+ $^M = 'a' x (1 << 16);
+
+would allocate a 64K buffer for use in an emergency. See the
+F<INSTALL> file in the Perl distribution for information on how to
+add custom C compilation flags when compiling perl. To discourage casual
+use of this advanced feature, there is no L<English|English> long name for
+this variable.
+
+=item $OSNAME
+
+=item $^O
+X<$^O> X<$OSNAME>
+
+The name of the operating system under which this copy of Perl was
+built, as determined during the configuration process. For examples
+see L<perlport/PLATFORMS>.
+
+The value is identical to C<$Config{'osname'}>. See also L<Config>
+and the B<-V> command-line switch documented in L<perlrun>.
+
+In Windows platforms, $^O is not very helpful: since it is always
+C<MSWin32>, it doesn't tell the difference between
+95/98/ME/NT/2000/XP/CE/.NET. Use Win32::GetOSName() or
+Win32::GetOSVersion() (see L<Win32> and L<perlport>) to distinguish
+between the variants.
+
+=item ${^OPEN}
+
+An internal variable used by PerlIO. A string in two parts, separated
+by a C<\0> byte, the first part describes the input layers, the second
+part describes the output layers.
+
+=item $PERLDB
+
+=item $^P
+X<$^P> X<$PERLDB>
+
+The internal variable for debugging support. The meanings of the
+various bits are subject to change, but currently indicate:
+
+=over 6
+
+=item 0x01
+
+Debug subroutine enter/exit.
+
+=item 0x02
+
+Line-by-line debugging. Causes DB::DB() subroutine to be called for each
+statement executed. Also causes saving source code lines (like 0x400).
+
+=item 0x04
+
+Switch off optimizations.
+
+=item 0x08
+
+Preserve more data for future interactive inspections.
+
+=item 0x10
+
+Keep info about source lines on which a subroutine is defined.
+
+=item 0x20
+
+Start with single-step on.
+
+=item 0x40
+
+Use subroutine address instead of name when reporting.
+
+=item 0x80
+
+Report C<goto &subroutine> as well.
+
+=item 0x100
+
+Provide informative "file" names for evals based on the place they were compiled.
+
+=item 0x200
+
+Provide informative names to anonymous subroutines based on the place they
+were compiled.
+
+=item 0x400
+
+Save source code lines into C<@{"_<$filename"}>.
+
+=back
+
+Some bits may be relevant at compile-time only, some at
+run-time only. This is a new mechanism and the details may change.
+See also L<perldebguts>.
+
+=item $LAST_REGEXP_CODE_RESULT
+
+=item $^R
+X<$^R> X<$LAST_REGEXP_CODE_RESULT>
+
+The result of evaluation of the last successful C<(?{ code })>
+regular expression assertion (see L<perlre>). May be written to.
+
+=item $EXCEPTIONS_BEING_CAUGHT
+
+=item $^S
+X<$^S> X<$EXCEPTIONS_BEING_CAUGHT>
+
+Current state of the interpreter.
+
+ $^S State
+ --------- -------------------
+ undef Parsing module/eval
+ true (1) Executing an eval
+ false (0) Otherwise
+
+The first state may happen in $SIG{__DIE__} and $SIG{__WARN__} handlers.
+
+=item $BASETIME
+
+=item $^T
+X<$^T> X<$BASETIME>
+
+The time at which the program began running, in seconds since the
+epoch (beginning of 1970). The values returned by the B<-M>, B<-A>,
+and B<-C> filetests are based on this value.
+
+=item ${^TAINT}
+
+Reflects if taint mode is on or off. 1 for on (the program was run with
+B<-T>), 0 for off, -1 when only taint warnings are enabled (i.e. with
+B<-t> or B<-TU>). This variable is read-only.
+
+=item ${^UNICODE}
+
+Reflects certain Unicode settings of Perl. See L<perlrun>
+documentation for the C<-C> switch for more information about
+the possible values. This variable is set during Perl startup
+and is thereafter read-only.
+
+=item ${^UTF8CACHE}
+
+This variable controls the state of the internal UTF-8 offset caching code.
+1 for on (the default), 0 for off, -1 to debug the caching code by checking
+all its results against linear scans, and panicking on any discrepancy.
+
+=item ${^UTF8LOCALE}
+
+This variable indicates whether a UTF-8 locale was detected by perl at
+startup. This information is used by perl when it's in
+adjust-utf8ness-to-locale mode (as when run with the C<-CL> command-line
+switch); see L<perlrun> for more info on this.
+
+=item $PERL_VERSION
+
+=item $^V
+X<$^V> X<$PERL_VERSION>
+
+The revision, version, and subversion of the Perl interpreter, represented
+as a C<version> object.
+
+This variable first appeared in perl 5.6.0; earlier versions of perl will
+see an undefined value. Before perl 5.10.0 $^V was represented as a v-string.
+
+$^V can be used to determine whether the Perl interpreter executing a
+script is in the right range of versions. (Mnemonic: use ^V for Version
+Control.) Example:
+
+ warn "Hashes not randomized!\n" if !$^V or $^V lt v5.8.1
+
+To convert C<$^V> into its string representation use sprintf()'s
+C<"%vd"> conversion:
+
+ printf "version is v%vd\n", $^V; # Perl's version
+
+See the documentation of C<use VERSION> and C<require VERSION>
+for a convenient way to fail if the running Perl interpreter is too old.
+
+See also C<$]> for an older representation of the Perl version.
+
+=item $WARNING
+
+=item $^W
+X<$^W> X<$WARNING>
+
+The current value of the warning switch, initially true if B<-w>
+was used, false otherwise, but directly modifiable. (Mnemonic:
+related to the B<-w> switch.) See also L<warnings>.
+
+=item ${^WARNING_BITS}
+
+The current set of warning checks enabled by the C<use warnings> pragma.
+See the documentation of C<warnings> for more details.
+
+=item ${^WIN32_SLOPPY_STAT}
+X<sitecustomize> X<sitecustomize.pl>
+
+If this variable is set to a true value, then stat() on Windows will
+not try to open the file. This means that the link count cannot be
+determined and file attributes may be out of date if additional
+hardlinks to the file exist. On the other hand, not opening the file
+is considerably faster, especially for files on network drives.
+
+This variable could be set in the F<sitecustomize.pl> file to
+configure the local Perl installation to use "sloppy" stat() by
+default. See the documentation for B<-f> in
+L<perlrun|perlrun/"Command Switches"> for more information about site
+customization.
+
+=item $EXECUTABLE_NAME
+
+=item $^X
+X<$^X> X<$EXECUTABLE_NAME>
+
+The name used to execute the current copy of Perl, from C's
+C<argv[0]> or (where supported) F</proc/self/exe>.
+
+Depending on the host operating system, the value of $^X may be
+a relative or absolute pathname of the perl program file, or may
+be the string used to invoke perl but not the pathname of the
+perl program file. Also, most operating systems permit invoking
+programs that are not in the PATH environment variable, so there
+is no guarantee that the value of $^X is in PATH. For VMS, the
+value may or may not include a version number.
+
+You usually can use the value of $^X to re-invoke an independent
+copy of the same perl that is currently running, e.g.,
+
+ @first_run = `$^X -le "print int rand 100 for 1..100"`;
+
+But recall that not all operating systems support forking or
+capturing of the output of commands, so this complex statement
+may not be portable.
+
+It is not safe to use the value of $^X as a path name of a file,
+as some operating systems that have a mandatory suffix on
+executable files do not require use of the suffix when invoking
+a command. To convert the value of $^X to a path name, use the
+following statements:
+
+ # Build up a set of file names (not command names).
+ use Config;
+ $this_perl = $^X;
+ if ($^O ne 'VMS')
+ {$this_perl .= $Config{_exe}
+ unless $this_perl =~ m/$Config{_exe}$/i;}
+
+Because many operating systems permit anyone with read access to
+the Perl program file to make a copy of it, patch the copy, and
+then execute the copy, the security-conscious Perl programmer
+should take care to invoke the installed copy of perl, not the
+copy referenced by $^X. The following statements accomplish
+this goal, and produce a pathname that can be invoked as a
+command or referenced as a file.
+
+ use Config;
+ $secure_perl_path = $Config{perlpath};
+ if ($^O ne 'VMS')
+ {$secure_perl_path .= $Config{_exe}
+ unless $secure_perl_path =~ m/$Config{_exe}$/i;}
+
+=item ARGV
+X<ARGV>
+
+The special filehandle that iterates over command-line filenames in
+C<@ARGV>. Usually written as the null filehandle in the angle operator
+C<< <> >>. Note that currently C<ARGV> only has its magical effect
+within the C<< <> >> operator; elsewhere it is just a plain filehandle
+corresponding to the last file opened by C<< <> >>. In particular,
+passing C<\*ARGV> as a parameter to a function that expects a filehandle
+may not cause your function to automatically read the contents of all the
+files in C<@ARGV>.
+
+=item $ARGV
+X<$ARGV>
+
+contains the name of the current file when reading from <>.
+
+=item @ARGV
+X<@ARGV>
+
+The array @ARGV contains the command-line arguments intended for
+the script. C<$#ARGV> is generally the number of arguments minus
+one, because C<$ARGV[0]> is the first argument, I<not> the program's
+command name itself. See C<$0> for the command name.
+
+=item ARGVOUT
+X<ARGVOUT>
+
+The special filehandle that points to the currently open output file
+when doing edit-in-place processing with B<-i>. Useful when you have
+to do a lot of inserting and don't want to keep modifying $_. See
+L<perlrun> for the B<-i> switch.
+
+=item @F
+X<@F>
+
+The array @F contains the fields of each line read in when autosplit
+mode is turned on. See L<perlrun> for the B<-a> switch. This array
+is package-specific, and must be declared or given a full package name
+if not in package main when running under C<strict 'vars'>.
+
+=item @INC
+X<@INC>
+
+The array @INC contains the list of places that the C<do EXPR>,
+C<require>, or C<use> constructs look for their library files. It
+initially consists of the arguments to any B<-I> command-line
+switches, followed by the default Perl library, probably
+F</usr/local/lib/perl>, followed by ".", to represent the current
+directory. ("." will not be appended if taint checks are enabled, either by
+C<-T> or by C<-t>.) If you need to modify this at runtime, you should use
+the C<use lib> pragma to get the machine-dependent library properly
+loaded also:
+
+ use lib '/mypath/libdir/';
+ use SomeMod;
+
+You can also insert hooks into the file inclusion system by putting Perl
+code directly into @INC. Those hooks may be subroutine references, array
+references or blessed objects. See L<perlfunc/require> for details.
+
+=item @ARG
+
+=item @_
+X<@_> X<@ARG>
+
+Within a subroutine the array @_ contains the parameters passed to that
+subroutine. See L<perlsub>.
+
+=item %INC
+X<%INC>
+
+The hash %INC contains entries for each filename included via the
+C<do>, C<require>, or C<use> operators. The key is the filename
+you specified (with module names converted to pathnames), and the
+value is the location of the file found. The C<require>
+operator uses this hash to determine whether a particular file has
+already been included.
+
+If the file was loaded via a hook (e.g. a subroutine reference, see
+L<perlfunc/require> for a description of these hooks), this hook is
+by default inserted into %INC in place of a filename. Note, however,
+that the hook may have set the %INC entry by itself to provide some more
+specific info.
+
+=item %ENV
+
+=item $ENV{expr}
+X<%ENV>
+
+The hash %ENV contains your current environment. Setting a
+value in C<ENV> changes the environment for any child processes
+you subsequently fork() off.
+
+=item %SIG
+
+=item $SIG{expr}
+X<%SIG>
+
+The hash C<%SIG> contains signal handlers for signals. For example:
+
+ sub handler { # 1st argument is signal name
+ my($sig) = @_;
+ print "Caught a SIG$sig--shutting down\n";
+ close(LOG);
+ exit(0);
+ }
+
+ $SIG{'INT'} = \&handler;
+ $SIG{'QUIT'} = \&handler;
+ ...
+ $SIG{'INT'} = 'DEFAULT'; # restore default action
+ $SIG{'QUIT'} = 'IGNORE'; # ignore SIGQUIT
+
+Using a value of C<'IGNORE'> usually has the effect of ignoring the
+signal, except for the C<CHLD> signal. See L<perlipc> for more about
+this special case.
+
+Here are some other examples:
+
+ $SIG{"PIPE"} = "Plumber"; # assumes main::Plumber (not recommended)
+ $SIG{"PIPE"} = \&Plumber; # just fine; assume current Plumber
+ $SIG{"PIPE"} = *Plumber; # somewhat esoteric
+ $SIG{"PIPE"} = Plumber(); # oops, what did Plumber() return??
+
+Be sure not to use a bareword as the name of a signal handler,
+lest you inadvertently call it.
+
+If your system has the sigaction() function then signal handlers are
+installed using it. This means you get reliable signal handling.
+
+The default delivery policy of signals changed in Perl 5.8.0 from
+immediate (also known as "unsafe") to deferred, also known as
+"safe signals". See L<perlipc> for more information.
+
+Certain internal hooks can be also set using the %SIG hash. The
+routine indicated by C<$SIG{__WARN__}> is called when a warning message is
+about to be printed. The warning message is passed as the first
+argument. The presence of a C<__WARN__> hook causes the ordinary printing
+of warnings to C<STDERR> to be suppressed. You can use this to save warnings
+in a variable, or turn warnings into fatal errors, like this:
+
+ local $SIG{__WARN__} = sub { die $_[0] };
+ eval $proggie;
+
+As the C<'IGNORE'> hook is not supported by C<__WARN__>, you can
+disable warnings using the empty subroutine:
+
+ local $SIG{__WARN__} = sub {};
+
+The routine indicated by C<$SIG{__DIE__}> is called when a fatal exception
+is about to be thrown. The error message is passed as the first
+argument. When a C<__DIE__> hook routine returns, the exception
+processing continues as it would have in the absence of the hook,
+unless the hook routine itself exits via a C<goto>, a loop exit, or a C<die()>.
+The C<__DIE__> handler is explicitly disabled during the call, so that you
+can die from a C<__DIE__> handler. Similarly for C<__WARN__>.
+
+Due to an implementation glitch, the C<$SIG{__DIE__}> hook is called
+even inside an eval(). Do not use this to rewrite a pending exception
+in C<$@>, or as a bizarre substitute for overriding C<CORE::GLOBAL::die()>.
+This strange action at a distance may be fixed in a future release
+so that C<$SIG{__DIE__}> is only called if your program is about
+to exit, as was the original intent. Any other use is deprecated.
+
+C<__DIE__>/C<__WARN__> handlers are very special in one respect:
+they may be called to report (probable) errors found by the parser.
+In such a case the parser may be in inconsistent state, so any
+attempt to evaluate Perl code from such a handler will probably
+result in a segfault. This means that warnings or errors that
+result from parsing Perl should be used with extreme caution, like
+this:
+
+ require Carp if defined $^S;
+ Carp::confess("Something wrong") if defined &Carp::confess;
+ die "Something wrong, but could not load Carp to give backtrace...
+ To see backtrace try starting Perl with -MCarp switch";
+
+Here the first line will load Carp I<unless> it is the parser who
+called the handler. The second line will print backtrace and die if
+Carp was available. The third line will be executed only if Carp was
+not available.
+
+See L<perlfunc/die>, L<perlfunc/warn>, L<perlfunc/eval>, and
+L<warnings> for additional information.
+
+=back
+
+=head2 Names that are no longer special
+
+These variables had special meaning in prior versions of Perl but now
+have no effect and will cause warnings if used. They are included
+here for historical reference.
+
+=over 8
+
+=item $#
+X<$#>
+
+C<$#> used to be a variable that could be used to format printed numbers.
+After a deprecation cycle, its magic was removed in Perl 5.10 and using it
+now triggers a warning: C<$# is no longer supported>.
+
+C<$#> is also used as sigil, which, when prepended on the name of an
+array, gives the index of the last element in that array.
+
+ my @array = ("a", "b", "c");
+ my $last_index = $#array; # $last_index is 2
+
+ for my $i (0 .. $#array) {
+ print "The value of index $i is $array[$i]\n";
+ }
+
+Also see L<perldata>.
+
+=item $*
+X<$*>
+
+C<$*> used to be a variable that enabled multiline matching.
+After a deprecation cycle, its magic was removed in Perl 5.10.
+Using it now triggers a warning: C<$* is no longer supported>.
+Use the C</s> and C</m> regexp modifiers instead.
+
+Also see L<perlre>.
+
+=back
+
+=head2 Error Indicators
+X<error> X<exception>
+
+The variables C<$@>, C<$!>, C<$^E>, and C<$?> contain information
+about different types of error conditions that may appear during
+execution of a Perl program. The variables are shown ordered by
+the "distance" between the subsystem which reported the error and
+the Perl process. They correspond to errors detected by the Perl
+interpreter, C library, operating system, or an external program,
+respectively.
+
+To illustrate the differences between these variables, consider the
+following Perl expression, which uses a single-quoted string:
+
+ eval q{
+ open my $pipe, "/cdrom/install |" or die $!;
+ my @res = <$pipe>;
+ close $pipe or die "bad pipe: $?, $!";
+ };
+
+After execution of this statement all 4 variables may have been set.
+
+C<$@> is set if the string to be C<eval>-ed did not compile (this
+may happen if C<open> or C<close> were imported with bad prototypes),
+or if Perl code executed during evaluation die()d . In these cases
+the value of $@ is the compile error, or the argument to C<die>
+(which will interpolate C<$!> and C<$?>). (See also L<Fatal>,
+though.)
+
+When the eval() expression above is executed, open(), C<< <PIPE> >>,
+and C<close> are translated to calls in the C run-time library and
+thence to the operating system kernel. C<$!> is set to the C library's
+C<errno> if one of these calls fails.
+
+Under a few operating systems, C<$^E> may contain a more verbose
+error indicator, such as in this case, "CDROM tray not closed."
+Systems that do not support extended error messages leave C<$^E>
+the same as C<$!>.
+
+Finally, C<$?> may be set to non-0 value if the external program
+F</cdrom/install> fails. The upper eight bits reflect specific
+error conditions encountered by the program (the program's exit()
+value). The lower eight bits reflect mode of failure, like signal
+death and core dump information See wait(2) for details. In
+contrast to C<$!> and C<$^E>, which are set only if error condition
+is detected, the variable C<$?> is set on each C<wait> or pipe
+C<close>, overwriting the old value. This is more like C<$@>, which
+on every eval() is always set on failure and cleared on success.
+
+For more details, see the individual descriptions at C<$@>, C<$!>, C<$^E>,
+and C<$?>.
+
+=head2 Technical Note on the Syntax of Variable Names
+
+Variable names in Perl can have several formats. Usually, they
+must begin with a letter or underscore, in which case they can be
+arbitrarily long (up to an internal limit of 251 characters) and
+may contain letters, digits, underscores, or the special sequence
+C<::> or C<'>. In this case, the part before the last C<::> or
+C<'> is taken to be a I<package qualifier>; see L<perlmod>.
+
+Perl variable names may also be a sequence of digits or a single
+punctuation or control character. These names are all reserved for
+special uses by Perl; for example, the all-digits names are used
+to hold data captured by backreferences after a regular expression
+match. Perl has a special syntax for the single-control-character
+names: It understands C<^X> (caret C<X>) to mean the control-C<X>
+character. For example, the notation C<$^W> (dollar-sign caret
+C<W>) is the scalar variable whose name is the single character
+control-C<W>. This is better than typing a literal control-C<W>
+into your program.
+
+Finally, new in Perl 5.6, Perl variable names may be alphanumeric
+strings that begin with control characters (or better yet, a caret).
+These variables must be written in the form C<${^Foo}>; the braces
+are not optional. C<${^Foo}> denotes the scalar variable whose
+name is a control-C<F> followed by two C<o>'s. These variables are
+reserved for future special uses by Perl, except for the ones that
+begin with C<^_> (control-underscore or caret-underscore). No
+control-character name that begins with C<^_> will acquire a special
+meaning in any future version of Perl; such names may therefore be
+used safely in programs. C<$^_> itself, however, I<is> reserved.
+
+Perl identifiers that begin with digits, control characters, or
+punctuation characters are exempt from the effects of the C<package>
+declaration and are always forced to be in package C<main>; they are
+also exempt from C<strict 'vars'> errors. A few other names are also
+exempt in these ways:
+
+ ENV STDIN
+ INC STDOUT
+ ARGV STDERR
+ ARGVOUT _
+ SIG
+
+In particular, the new special C<${^_XYZ}> variables are always taken
+to be in package C<main>, regardless of any C<package> declarations
+presently in scope.
+
+=head1 BUGS
+
+Due to an unfortunate accident of Perl's implementation, C<use
+English> imposes a considerable performance penalty on all regular
+expression matches in a program, regardless of whether they occur
+in the scope of C<use English>. For that reason, saying C<use
+English> in libraries is strongly discouraged. See the
+Devel::SawAmpersand module documentation from CPAN
+( http://www.cpan.org/modules/by-module/Devel/ )
+for more information. Writing C<use English '-no_match_vars';>
+avoids the performance penalty.
+
+Having to even think about the C<$^S> variable in your exception
+handlers is simply wrong. C<$SIG{__DIE__}> as currently implemented
+invites grievous and difficult to track down errors. Avoid it
+and use an C<END{}> or CORE::GLOBAL::die override instead.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlvmesa.pod b/Master/tlpkg/tlperl/lib/pods/perlvmesa.pod
new file mode 100644
index 00000000000..98fa5ec9cfd
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlvmesa.pod
@@ -0,0 +1,131 @@
+
+This document is written in pod format hence there are punctuation
+characters in odd places. Do not worry, you've apparently got
+the ASCII->EBCDIC translation worked out correctly. You can read
+more about pod in pod/perlpod.pod or the short summary in the
+INSTALL file.
+
+=head1 NAME
+
+README.vmesa - building and installing Perl for VM/ESA.
+
+=head1 SYNOPSIS
+
+This document will help you Configure, build, test and install Perl
+on VM/ESA.
+
+=head1 DESCRIPTION
+
+This is a fully ported perl for VM/ESA 2.3.0. It may work on
+other versions, but that's the one we've tested it on.
+
+If you've downloaded the binary distribution, it needs to be
+installed below /usr/local. Source code distributions have an
+automated "make install" step that means you do not need to extract
+the source code below /usr/local (though that is where it will be
+installed by default). You may need to worry about the networking
+configuration files discussed in the last bullet below.
+
+=head2 Unpacking Perl Distribution on VM/ESA
+
+To extract an ASCII tar archive on VM/ESA, try this:
+
+ pax -o to=IBM-1047,from=ISO8859-1 -r < latest.tar
+
+=head2 Setup Perl and utilities on VM/ESA
+
+GNU make for VM/ESA, which may be required for the build of perl,
+is available from:
+
+ http://vm.marist.edu/~neale/vmoe.html
+
+=head2 Configure Perl on VM/ESA
+
+Once you've unpacked the distribution, run Configure (see INSTALL for
+full discussion of the Configure options), and then run make, then
+"make test" then "make install" (this last step may require UID=0
+privileges).
+
+There is a "hints" file for vmesa that specifies the correct values
+for most things. Some things to watch out for are:
+
+=over 4
+
+=item *
+
+this port does support dynamic loading but it's not had much testing
+
+=item *
+
+Don't turn on the compiler optimization flag "-O". There's
+a bug in the compiler (APAR PQ18812) that generates some bad code
+the optimizer is on.
+
+=item *
+
+As VM/ESA doesn't fully support the fork() API programs relying on
+this call will not work. I've replaced fork()/exec() with spawn()
+and the standalone exec() with spawn(). This has a side effect when
+opening unnamed pipes in a shell script: there is no child process
+generated under.
+
+=item *
+
+At the moment the hints file for VM/ESA basically bypasses all of the
+automatic configuration process. This is because Configure relies on:
+1. The header files living in the Byte File System (you could put the
+there if you want); 2. The C preprocessor including the #include
+statements in the preprocessor output (.i) file.
+
+=back
+
+=head2 Testing Anomalies of Perl on VM/ESA
+
+The "make test" step runs a Perl Verification Procedure, usually before
+installation. As the 5.6.1 kit was being assembled
+the following "failures" were known to appear on some machines
+during "make test" (mostly due to ASCII vs. EBCDIC conflicts),
+your results may differ:
+
+[the list of failures being compiled]
+
+=head2 Usage Hints for Perl on VM/ESA
+
+When using perl on VM/ESA please keep in mind that the EBCDIC and ASCII
+character sets are different. Perl builtin functions that may behave
+differently under EBCDIC are mentioned in the perlport.pod document.
+
+OpenEdition (UNIX System Services) does not (yet) support the #! means
+of script invocation.
+See:
+
+ head `whence perldoc`
+
+for an example of how to use the "eval exec" trick to ask the shell to
+have perl run your scripts for you.
+
+=head1 AUTHORS
+
+Neale Ferguson.
+
+=head1 SEE ALSO
+
+L<INSTALL>, L<perlport>, L<perlebcdic>.
+
+=head2 Mailing list for Perl on VM/ESA
+
+If you are interested in the VM/ESA, z/OS (formerly known as OS/390)
+and POSIX-BC (BS2000) ports of Perl then see the perl-mvs mailing list.
+To subscribe, send an empty message to perl-mvs-subscribe@perl.org.
+
+See also:
+
+ http://lists.perl.org/showlist.cgi?name=perl-mvs
+
+There are web archives of the mailing list at:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl-mvs/
+ http://archive.develooper.com/perl-mvs@perl.org/
+
+=cut
+
diff --git a/Master/tlpkg/tlperl/lib/pods/perlvms.pod b/Master/tlpkg/tlperl/lib/pods/perlvms.pod
new file mode 100644
index 00000000000..17175db3bd9
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlvms.pod
@@ -0,0 +1,1226 @@
+=head1 NAME
+
+perlvms - VMS-specific documentation for Perl
+
+=head1 DESCRIPTION
+
+Gathered below are notes describing details of Perl 5's
+behavior on VMS. They are a supplement to the regular Perl 5
+documentation, so we have focussed on the ways in which Perl
+5 functions differently under VMS than it does under Unix,
+and on the interactions between Perl and the rest of the
+operating system. We haven't tried to duplicate complete
+descriptions of Perl features from the main Perl
+documentation, which can be found in the F<[.pod]>
+subdirectory of the Perl distribution.
+
+We hope these notes will save you from confusion and lost
+sleep when writing Perl scripts on VMS. If you find we've
+missed something you think should appear here, please don't
+hesitate to drop a line to vmsperl@perl.org.
+
+=head1 Installation
+
+Directions for building and installing Perl 5 can be found in
+the file F<README.vms> in the main source directory of the
+Perl distribution..
+
+=head1 Organization of Perl Images
+
+=head2 Core Images
+
+During the installation process, three Perl images are produced.
+F<Miniperl.Exe> is an executable image which contains all of
+the basic functionality of Perl, but cannot take advantage of
+Perl extensions. It is used to generate several files needed
+to build the complete Perl and various extensions. Once you've
+finished installing Perl, you can delete this image.
+
+Most of the complete Perl resides in the shareable image
+F<PerlShr.Exe>, which provides a core to which the Perl executable
+image and all Perl extensions are linked. You should place this
+image in F<Sys$Share>, or define the logical name F<PerlShr> to
+translate to the full file specification of this image. It should
+be world readable. (Remember that if a user has execute only access
+to F<PerlShr>, VMS will treat it as if it were a privileged shareable
+image, and will therefore require all downstream shareable images to be
+INSTALLed, etc.)
+
+
+Finally, F<Perl.Exe> is an executable image containing the main
+entry point for Perl, as well as some initialization code. It
+should be placed in a public directory, and made world executable.
+In order to run Perl with command line arguments, you should
+define a foreign command to invoke this image.
+
+=head2 Perl Extensions
+
+Perl extensions are packages which provide both XS and Perl code
+to add new functionality to perl. (XS is a meta-language which
+simplifies writing C code which interacts with Perl, see
+L<perlxs> for more details.) The Perl code for an
+extension is treated like any other library module - it's
+made available in your script through the appropriate
+C<use> or C<require> statement, and usually defines a Perl
+package containing the extension.
+
+The portion of the extension provided by the XS code may be
+connected to the rest of Perl in either of two ways. In the
+B<static> configuration, the object code for the extension is
+linked directly into F<PerlShr.Exe>, and is initialized whenever
+Perl is invoked. In the B<dynamic> configuration, the extension's
+machine code is placed into a separate shareable image, which is
+mapped by Perl's DynaLoader when the extension is C<use>d or
+C<require>d in your script. This allows you to maintain the
+extension as a separate entity, at the cost of keeping track of the
+additional shareable image. Most extensions can be set up as either
+static or dynamic.
+
+The source code for an extension usually resides in its own
+directory. At least three files are generally provided:
+I<Extshortname>F<.xs> (where I<Extshortname> is the portion of
+the extension's name following the last C<::>), containing
+the XS code, I<Extshortname>F<.pm>, the Perl library module
+for the extension, and F<Makefile.PL>, a Perl script which uses
+the C<MakeMaker> library modules supplied with Perl to generate
+a F<Descrip.MMS> file for the extension.
+
+=head2 Installing static extensions
+
+Since static extensions are incorporated directly into
+F<PerlShr.Exe>, you'll have to rebuild Perl to incorporate a
+new extension. You should edit the main F<Descrip.MMS> or F<Makefile>
+you use to build Perl, adding the extension's name to the C<ext>
+macro, and the extension's object file to the C<extobj> macro.
+You'll also need to build the extension's object file, either
+by adding dependencies to the main F<Descrip.MMS>, or using a
+separate F<Descrip.MMS> for the extension. Then, rebuild
+F<PerlShr.Exe> to incorporate the new code.
+
+Finally, you'll need to copy the extension's Perl library
+module to the F<[.>I<Extname>F<]> subdirectory under one
+of the directories in C<@INC>, where I<Extname> is the name
+of the extension, with all C<::> replaced by C<.> (e.g.
+the library module for extension Foo::Bar would be copied
+to a F<[.Foo.Bar]> subdirectory).
+
+=head2 Installing dynamic extensions
+
+In general, the distributed kit for a Perl extension includes
+a file named Makefile.PL, which is a Perl program which is used
+to create a F<Descrip.MMS> file which can be used to build and
+install the files required by the extension. The kit should be
+unpacked into a directory tree B<not> under the main Perl source
+directory, and the procedure for building the extension is simply
+
+ $ perl Makefile.PL ! Create Descrip.MMS
+ $ mmk ! Build necessary files
+ $ mmk test ! Run test code, if supplied
+ $ mmk install ! Install into public Perl tree
+
+I<N.B.> The procedure by which extensions are built and
+tested creates several levels (at least 4) under the
+directory in which the extension's source files live.
+For this reason if you are running a version of VMS prior
+to V7.1 you shouldn't nest the source directory
+too deeply in your directory structure lest you exceed RMS'
+maximum of 8 levels of subdirectory in a filespec. (You
+can use rooted logical names to get another 8 levels of
+nesting, if you can't place the files near the top of
+the physical directory structure.)
+
+VMS support for this process in the current release of Perl
+is sufficient to handle most extensions. However, it does
+not yet recognize extra libraries required to build shareable
+images which are part of an extension, so these must be added
+to the linker options file for the extension by hand. For
+instance, if the F<PGPLOT> extension to Perl requires the
+F<PGPLOTSHR.EXE> shareable image in order to properly link
+the Perl extension, then the line C<PGPLOTSHR/Share> must
+be added to the linker options file F<PGPLOT.Opt> produced
+during the build process for the Perl extension.
+
+By default, the shareable image for an extension is placed in
+the F<[.lib.site_perl.auto>I<Arch>.I<Extname>F<]> directory of the
+installed Perl directory tree (where I<Arch> is F<VMS_VAX> or
+F<VMS_AXP>, and I<Extname> is the name of the extension, with
+each C<::> translated to C<.>). (See the MakeMaker documentation
+for more details on installation options for extensions.)
+However, it can be manually placed in any of several locations:
+
+=over 4
+
+=item *
+
+the F<[.Lib.Auto.>I<Arch>I<$PVers>I<Extname>F<]> subdirectory
+of one of the directories in C<@INC> (where I<PVers>
+is the version of Perl you're using, as supplied in C<$]>,
+with '.' converted to '_'), or
+
+=item *
+
+one of the directories in C<@INC>, or
+
+=item *
+
+a directory which the extensions Perl library module
+passes to the DynaLoader when asking it to map
+the shareable image, or
+
+=item *
+
+F<Sys$Share> or F<Sys$Library>.
+
+=back
+
+If the shareable image isn't in any of these places, you'll need
+to define a logical name I<Extshortname>, where I<Extshortname>
+is the portion of the extension's name after the last C<::>, which
+translates to the full file specification of the shareable image.
+
+=head1 File specifications
+
+=head2 Syntax
+
+We have tried to make Perl aware of both VMS-style and Unix-style file
+specifications wherever possible. You may use either style, or both,
+on the command line and in scripts, but you may not combine the two
+styles within a single file specification. VMS Perl interprets Unix
+pathnames in much the same way as the CRTL (I<e.g.> the first component
+of an absolute path is read as the device name for the VMS file
+specification). There are a set of functions provided in the
+C<VMS::Filespec> package for explicit interconversion between VMS and
+Unix syntax; its documentation provides more details.
+
+We've tried to minimize the dependence of Perl library
+modules on Unix syntax, but you may find that some of these,
+as well as some scripts written for Unix systems, will
+require that you use Unix syntax, since they will assume that
+'/' is the directory separator, I<etc.> If you find instances
+of this in the Perl distribution itself, please let us know,
+so we can try to work around them.
+
+Also when working on Perl programs on VMS, if you need a syntax
+in a specific operating system format, then you need either to
+check the appropriate DECC$ feature logical, or call a conversion
+routine to force it to that format.
+
+The feature logical name DECC$FILENAME_UNIX_REPORT modifies traditional
+Perl behavior in the conversion of file specifications from Unix to VMS
+format in order to follow the extended character handling rules now
+expected by the CRTL. Specifically, when this feature is in effect, the
+C<./.../> in a Unix path is now translated to C<[.^.^.^.]> instead of
+the traditional VMS C<[...]>. To be compatible with what MakeMaker
+expects, if a VMS path cannot be translated to a Unix path, it is
+passed through unchanged, so C<unixify("[...]")> will return C<[...]>.
+
+The handling of extended characters is largely complete in the
+VMS-specific C infrastructure of Perl, but more work is still needed to
+fully support extended syntax filenames in several core modules. In
+particular, at this writing PathTools has only partial support for
+directories containing some extended characters.
+
+There are several ambiguous cases where a conversion routine cannot
+determine whether an input filename is in Unix format or in VMS format,
+since now both VMS and Unix file specifications may have characters in
+them that could be mistaken for syntax delimiters of the other type. So
+some pathnames simply cannot be used in a mode that allows either type
+of pathname to be present. Perl will tend to assume that an ambiguous
+filename is in Unix format.
+
+Allowing "." as a version delimiter is simply incompatible with
+determining whether a pathname is in VMS format or in Unix format with
+extended file syntax. There is no way to know whether "perl-5.8.6" is a
+Unix "perl-5.8.6" or a VMS "perl-5.8;6" when passing it to unixify() or
+vmsify().
+
+The DECC$FILENAME_UNIX_REPORT logical name controls how Perl interprets
+filenames to the extent that Perl uses the CRTL internally for many
+purposes, and attempts to follow CRTL conventions for reporting
+filenames. The DECC$FILENAME_UNIX_ONLY feature differs in that it
+expects all filenames passed to the C run-time to be already in Unix
+format. This feature is not yet supported in Perl since Perl uses
+traditional OpenVMS file specifications internally and in the test
+harness, and it is not yet clear whether this mode will be useful or
+useable. The feature logical name DECC$POSIX_COMPLIANT_PATHNAMES is new
+with the RMS Symbolic Link SDK and included with OpenVMS v8.3, but is
+not yet supported in Perl.
+
+=head2 Filename Case
+
+Perl follows VMS defaults and override settings in preserving (or not
+preserving) filename case. Case is not preserved on ODS-2 formatted
+volumes on any architecture. On ODS-5 volumes, filenames may be case
+preserved depending on process and feature settings. Perl now honors
+DECC$EFS_CASE_PRESERVE and DECC$ARGV_PARSE_STYLE on those systems where
+the CRTL supports these features. When these features are not enabled
+or the CRTL does not support them, Perl follows the traditional CRTL
+behavior of downcasing command-line arguments and returning file
+specifications in lower case only.
+
+I<N. B.> It is very easy to get tripped up using a mixture of other
+programs, external utilities, and Perl scripts that are in varying
+states of being able to handle case preservation. For example, a file
+created by an older version of an archive utility or a build utility
+such as MMK or MMS may generate a filename in all upper case even on an
+ODS-5 volume. If this filename is later retrieved by a Perl script or
+module in a case preserving environment, that upper case name may not
+match the mixed-case or lower-case expections of the Perl code. Your
+best bet is to follow an all-or-nothing approach to case preservation:
+either don't use it at all, or make sure your entire toolchain and
+application environment support and use it.
+
+OpenVMS Alpha v7.3-1 and later and all version of OpenVMS I64 support
+case sensitivity as a process setting (see C<SET PROCESS
+/CASE_LOOKUP=SENSITIVE>). Perl does not currently suppport case
+sensitivity on VMS, but it may in the future, so Perl programs should
+use the C<< File::Spec->case_tolerant >> method to determine the state, and
+not the C<$^O> variable.
+
+=head2 Symbolic Links
+
+When built on an ODS-5 volume with symbolic links enabled, Perl by
+default supports symbolic links when the requisite support is available
+in the filesystem and CRTL (generally 64-bit OpenVMS v8.3 and later).
+There are a number of limitations and caveats to be aware of when
+working with symbolic links on VMS. Most notably, the target of a valid
+symbolic link must be expressed as a Unix-style path and it must exist
+on a volume visible from your POSIX root (see the C<SHOW ROOT> command
+in DCL help). For further details on symbolic link capabilities and
+requirements, see chapter 12 of the CRTL manual that ships with OpenVMS
+v8.3 or later.
+
+=head2 Wildcard expansion
+
+File specifications containing wildcards are allowed both on
+the command line and within Perl globs (e.g. C<E<lt>*.cE<gt>>). If
+the wildcard filespec uses VMS syntax, the resultant
+filespecs will follow VMS syntax; if a Unix-style filespec is
+passed in, Unix-style filespecs will be returned.
+Similar to the behavior of wildcard globbing for a Unix shell,
+one can escape command line wildcards with double quotation
+marks C<"> around a perl program command line argument. However,
+owing to the stripping of C<"> characters carried out by the C
+handling of argv you will need to escape a construct such as
+this one (in a directory containing the files F<PERL.C>, F<PERL.EXE>,
+F<PERL.H>, and F<PERL.OBJ>):
+
+ $ perl -e "print join(' ',@ARGV)" perl.*
+ perl.c perl.exe perl.h perl.obj
+
+in the following triple quoted manner:
+
+ $ perl -e "print join(' ',@ARGV)" """perl.*"""
+ perl.*
+
+In both the case of unquoted command line arguments or in calls
+to C<glob()> VMS wildcard expansion is performed. (csh-style
+wildcard expansion is available if you use C<File::Glob::glob>.)
+If the wildcard filespec contains a device or directory
+specification, then the resultant filespecs will also contain
+a device and directory; otherwise, device and directory
+information are removed. VMS-style resultant filespecs will
+contain a full device and directory, while Unix-style
+resultant filespecs will contain only as much of a directory
+path as was present in the input filespec. For example, if
+your default directory is Perl_Root:[000000], the expansion
+of C<[.t]*.*> will yield filespecs like
+"perl_root:[t]base.dir", while the expansion of C<t/*/*> will
+yield filespecs like "t/base.dir". (This is done to match
+the behavior of glob expansion performed by Unix shells.)
+
+Similarly, the resultant filespec will contain the file version
+only if one was present in the input filespec.
+
+
+=head2 Pipes
+
+Input and output pipes to Perl filehandles are supported; the
+"file name" is passed to lib$spawn() for asynchronous
+execution. You should be careful to close any pipes you have
+opened in a Perl script, lest you leave any "orphaned"
+subprocesses around when Perl exits.
+
+You may also use backticks to invoke a DCL subprocess, whose
+output is used as the return value of the expression. The
+string between the backticks is handled as if it were the
+argument to the C<system> operator (see below). In this case,
+Perl will wait for the subprocess to complete before continuing.
+
+The mailbox (MBX) that perl can create to communicate with a pipe
+defaults to a buffer size of 8192 on 64-bit systems, 512 on VAX. The
+default buffer size is adjustable via the logical name PERL_MBX_SIZE
+provided that the value falls between 128 and the SYSGEN parameter
+MAXBUF inclusive. For example, to set the mailbox size to 32767 use
+C<$ENV{'PERL_MBX_SIZE'} = 32767;> and then open and use pipe constructs.
+An alternative would be to issue the command:
+
+ $ Define PERL_MBX_SIZE 32767
+
+before running your wide record pipe program. A larger value may
+improve performance at the expense of the BYTLM UAF quota.
+
+=head1 PERL5LIB and PERLLIB
+
+The PERL5LIB and PERLLIB logical names work as documented in L<perl>,
+except that the element separator is '|' instead of ':'. The
+directory specifications may use either VMS or Unix syntax.
+
+=head1 The Perl Forked Debugger
+
+The Perl forked debugger places the debugger commands and output in a
+separate X-11 terminal window so that commands and output from multiple
+processes are not mixed together.
+
+Perl on VMS supports an emulation of the forked debugger when Perl is
+run on a VMS system that has X11 support installed.
+
+To use the forked debugger, you need to have the default display set to an
+X-11 Server and some environment variables set that Unix expects.
+
+The forked debugger requires the environment variable C<TERM> to be C<xterm>,
+and the environment variable C<DISPLAY> to exist. C<xterm> must be in
+lower case.
+
+ $define TERM "xterm"
+
+ $define DISPLAY "hostname:0.0"
+
+Currently the value of C<DISPLAY> is ignored. It is recommended that it be set
+to be the hostname of the display, the server and screen in Unix notation. In
+the future the value of DISPLAY may be honored by Perl instead of using the
+default display.
+
+It may be helpful to always use the forked debugger so that script I/O is
+separated from debugger I/O. You can force the debugger to be forked by
+assigning a value to the logical name <PERLDB_PIDS> that is not a process
+identification number.
+
+ $define PERLDB_PIDS XXXX
+
+
+=head1 PERL_VMS_EXCEPTION_DEBUG
+
+The PERL_VMS_EXCEPTION_DEBUG being defined as "ENABLE" will cause the VMS
+debugger to be invoked if a fatal exception that is not otherwise
+handled is raised. The purpose of this is to allow debugging of
+internal Perl problems that would cause such a condition.
+
+This allows the programmer to look at the execution stack and variables to
+find out the cause of the exception. As the debugger is being invoked as
+the Perl interpreter is about to do a fatal exit, continuing the execution
+in debug mode is usally not practical.
+
+Starting Perl in the VMS debugger may change the program execution
+profile in a way that such problems are not reproduced.
+
+The C<kill> function can be used to test this functionality from within
+a program.
+
+In typical VMS style, only the first letter of the value of this logical
+name is actually checked in a case insensitive mode, and it is considered
+enabled if it is the value "T","1" or "E".
+
+This logical name must be defined before Perl is started.
+
+=head1 Command line
+
+=head2 I/O redirection and backgrounding
+
+Perl for VMS supports redirection of input and output on the
+command line, using a subset of Bourne shell syntax:
+
+=over 4
+
+=item *
+
+C<E<lt>file> reads stdin from C<file>,
+
+=item *
+
+C<E<gt>file> writes stdout to C<file>,
+
+=item *
+
+C<E<gt>E<gt>file> appends stdout to C<file>,
+
+=item *
+
+C<2E<gt>file> writes stderr to C<file>,
+
+=item *
+
+C<2E<gt>E<gt>file> appends stderr to C<file>, and
+
+=item *
+
+C<< 2>&1 >> redirects stderr to stdout.
+
+=back
+
+In addition, output may be piped to a subprocess, using the
+character '|'. Anything after this character on the command
+line is passed to a subprocess for execution; the subprocess
+takes the output of Perl as its input.
+
+Finally, if the command line ends with '&', the entire
+command is run in the background as an asynchronous
+subprocess.
+
+=head2 Command line switches
+
+The following command line switches behave differently under
+VMS than described in L<perlrun>. Note also that in order
+to pass uppercase switches to Perl, you need to enclose
+them in double-quotes on the command line, since the CRTL
+downcases all unquoted strings.
+
+On newer 64 bit versions of OpenVMS, a process setting now
+controls if the quoting is needed to preserve the case of
+command line arguments.
+
+=over 4
+
+=item -i
+
+If the C<-i> switch is present but no extension for a backup
+copy is given, then inplace editing creates a new version of
+a file; the existing copy is not deleted. (Note that if
+an extension is given, an existing file is renamed to the backup
+file, as is the case under other operating systems, so it does
+not remain as a previous version under the original filename.)
+
+=item -S
+
+If the C<"-S"> or C<-"S"> switch is present I<and> the script
+name does not contain a directory, then Perl translates the
+logical name DCL$PATH as a searchlist, using each translation
+as a directory in which to look for the script. In addition,
+if no file type is specified, Perl looks in each directory
+for a file matching the name specified, with a blank type,
+a type of F<.pl>, and a type of F<.com>, in that order.
+
+=item -u
+
+The C<-u> switch causes the VMS debugger to be invoked
+after the Perl program is compiled, but before it has
+run. It does not create a core dump file.
+
+=back
+
+=head1 Perl functions
+
+As of the time this document was last revised, the following
+Perl functions were implemented in the VMS port of Perl
+(functions marked with * are discussed in more detail below):
+
+ file tests*, abs, alarm, atan, backticks*, binmode*, bless,
+ caller, chdir, chmod, chown, chomp, chop, chr,
+ close, closedir, cos, crypt*, defined, delete, die, do, dump*,
+ each, endgrent, endpwent, eof, eval, exec*, exists, exit, exp,
+ fileno, flock getc, getgrent*, getgrgid*, getgrnam, getlogin, getppid,
+ getpwent*, getpwnam*, getpwuid*, glob, gmtime*, goto,
+ grep, hex, ioctl, import, index, int, join, keys, kill*,
+ last, lc, lcfirst, lchown*, length, link*, local, localtime, log, lstat, m//,
+ map, mkdir, my, next, no, oct, open, opendir, ord, pack,
+ pipe, pop, pos, print, printf, push, q//, qq//, qw//,
+ qx//*, quotemeta, rand, read, readdir, readlink*, redo, ref, rename,
+ require, reset, return, reverse, rewinddir, rindex,
+ rmdir, s///, scalar, seek, seekdir, select(internal),
+ select (system call)*, setgrent, setpwent, shift, sin, sleep,
+ socketpair, sort, splice, split, sprintf, sqrt, srand, stat,
+ study, substr, symlink*, sysread, system*, syswrite, tell,
+ telldir, tie, time, times*, tr///, uc, ucfirst, umask,
+ undef, unlink*, unpack, untie, unshift, use, utime*,
+ values, vec, wait, waitpid*, wantarray, warn, write, y///
+
+The following functions were not implemented in the VMS port,
+and calling them produces a fatal error (usually) or
+undefined behavior (rarely, we hope):
+
+ chroot, dbmclose, dbmopen, fork*, getpgrp, getpriority,
+ msgctl, msgget, msgsend, msgrcv, semctl,
+ semget, semop, setpgrp, setpriority, shmctl, shmget,
+ shmread, shmwrite, syscall
+
+The following functions are available on Perls compiled with Dec C
+5.2 or greater and running VMS 7.0 or greater:
+
+ truncate
+
+The following functions are available on Perls built on VMS 7.2 or
+greater:
+
+ fcntl (without locking)
+
+The following functions may or may not be implemented,
+depending on what type of socket support you've built into
+your copy of Perl:
+
+ accept, bind, connect, getpeername,
+ gethostbyname, getnetbyname, getprotobyname,
+ getservbyname, gethostbyaddr, getnetbyaddr,
+ getprotobynumber, getservbyport, gethostent,
+ getnetent, getprotoent, getservent, sethostent,
+ setnetent, setprotoent, setservent, endhostent,
+ endnetent, endprotoent, endservent, getsockname,
+ getsockopt, listen, recv, select(system call)*,
+ send, setsockopt, shutdown, socket
+
+The following function is available on Perls built on 64 bit OpenVMS v8.2
+with hard links enabled on an ODS-5 formatted build disk. CRTL support
+is in principle available as of OpenVMS v7.3-1, and better configuration
+support could detect this.
+
+ link
+
+The following functions are available on Perls built on 64 bit OpenVMS
+v8.2 and later. CRTL support is in principle available as of OpenVMS
+v7.3-2, and better configuration support could detect this.
+
+ getgrgid, getgrnam, getpwnam, getpwuid,
+ setgrent, ttyname
+
+The following functions are available on Perls built on 64 bit OpenVMS v8.2
+and later.
+
+ statvfs, socketpair
+
+=over 4
+
+=item File tests
+
+The tests C<-b>, C<-B>, C<-c>, C<-C>, C<-d>, C<-e>, C<-f>,
+C<-o>, C<-M>, C<-s>, C<-S>, C<-t>, C<-T>, and C<-z> work as
+advertised. The return values for C<-r>, C<-w>, and C<-x>
+tell you whether you can actually access the file; this may
+not reflect the UIC-based file protections. Since real and
+effective UIC don't differ under VMS, C<-O>, C<-R>, C<-W>,
+and C<-X> are equivalent to C<-o>, C<-r>, C<-w>, and C<-x>.
+Similarly, several other tests, including C<-A>, C<-g>, C<-k>,
+C<-l>, C<-p>, and C<-u>, aren't particularly meaningful under
+VMS, and the values returned by these tests reflect whatever
+your CRTL C<stat()> routine does to the equivalent bits in the
+st_mode field. Finally, C<-d> returns true if passed a device
+specification without an explicit directory (e.g. C<DUA1:>), as
+well as if passed a directory.
+
+There are DECC feature logical names AND ODS-5 volume attributes that
+also control what values are returned for the date fields.
+
+Note: Some sites have reported problems when using the file-access
+tests (C<-r>, C<-w>, and C<-x>) on files accessed via DEC's DFS.
+Specifically, since DFS does not currently provide access to the
+extended file header of files on remote volumes, attempts to
+examine the ACL fail, and the file tests will return false,
+with C<$!> indicating that the file does not exist. You can
+use C<stat> on these files, since that checks UIC-based protection
+only, and then manually check the appropriate bits, as defined by
+your C compiler's F<stat.h>, in the mode value it returns, if you
+need an approximation of the file's protections.
+
+=item backticks
+
+Backticks create a subprocess, and pass the enclosed string
+to it for execution as a DCL command. Since the subprocess is
+created directly via C<lib$spawn()>, any valid DCL command string
+may be specified.
+
+=item binmode FILEHANDLE
+
+The C<binmode> operator will attempt to insure that no translation
+of carriage control occurs on input from or output to this filehandle.
+Since this involves reopening the file and then restoring its
+file position indicator, if this function returns FALSE, the
+underlying filehandle may no longer point to an open file, or may
+point to a different position in the file than before C<binmode>
+was called.
+
+Note that C<binmode> is generally not necessary when using normal
+filehandles; it is provided so that you can control I/O to existing
+record-structured files when necessary. You can also use the
+C<vmsfopen> function in the VMS::Stdio extension to gain finer
+control of I/O to files and devices with different record structures.
+
+=item crypt PLAINTEXT, USER
+
+The C<crypt> operator uses the C<sys$hash_password> system
+service to generate the hashed representation of PLAINTEXT.
+If USER is a valid username, the algorithm and salt values
+are taken from that user's UAF record. If it is not, then
+the preferred algorithm and a salt of 0 are used. The
+quadword encrypted value is returned as an 8-character string.
+
+The value returned by C<crypt> may be compared against
+the encrypted password from the UAF returned by the C<getpw*>
+functions, in order to authenticate users. If you're
+going to do this, remember that the encrypted password in
+the UAF was generated using uppercase username and
+password strings; you'll have to upcase the arguments to
+C<crypt> to insure that you'll get the proper value:
+
+ sub validate_passwd {
+ my($user,$passwd) = @_;
+ my($pwdhash);
+ if ( !($pwdhash = (getpwnam($user))[1]) ||
+ $pwdhash ne crypt("\U$passwd","\U$name") ) {
+ intruder_alert($name);
+ }
+ return 1;
+ }
+
+
+=item die
+
+C<die> will force the native VMS exit status to be an SS$_ABORT code
+if neither of the $! or $? status values are ones that would cause
+the native status to be interpreted as being what VMS classifies as
+SEVERE_ERROR severity for DCL error handling.
+
+When C<PERL_VMS_POSIX_EXIT> is active (see L</"$?"> below), the native VMS exit
+status value will have either one of the C<$!> or C<$?> or C<$^E> or
+the Unix value 255 encoded into it in a way that the effective original
+value can be decoded by other programs written in C, including Perl
+and the GNV package. As per the normal non-VMS behavior of C<die> if
+either C<$!> or C<$?> are non-zero, one of those values will be
+encoded into a native VMS status value. If both of the Unix status
+values are 0, and the C<$^E> value is set one of ERROR or SEVERE_ERROR
+severity, then the C<$^E> value will be used as the exit code as is.
+If none of the above apply, the Unix value of 255 will be encoded into
+a native VMS exit status value.
+
+Please note a significant difference in the behavior of C<die> in
+the C<PERL_VMS_POSIX_EXIT> mode is that it does not force a VMS
+SEVERE_ERROR status on exit. The Unix exit values of 2 through
+255 will be encoded in VMS status values with severity levels of
+SUCCESS. The Unix exit value of 1 will be encoded in a VMS status
+value with a severity level of ERROR. This is to be compatible with
+how the VMS C library encodes these values.
+
+The minimum severity level set by C<die> in C<PERL_VMS_POSIX_EXIT> mode
+may be changed to be ERROR or higher in the future depending on the
+results of testing and further review.
+
+See L</"$?"> for a description of the encoding of the Unix value to
+produce a native VMS status containing it.
+
+
+=item dump
+
+Rather than causing Perl to abort and dump core, the C<dump>
+operator invokes the VMS debugger. If you continue to
+execute the Perl program under the debugger, control will
+be transferred to the label specified as the argument to
+C<dump>, or, if no label was specified, back to the
+beginning of the program. All other state of the program
+(I<e.g.> values of variables, open file handles) are not
+affected by calling C<dump>.
+
+=item exec LIST
+
+A call to C<exec> will cause Perl to exit, and to invoke the command
+given as an argument to C<exec> via C<lib$do_command>. If the
+argument begins with '@' or '$' (other than as part of a filespec),
+then it is executed as a DCL command. Otherwise, the first token on
+the command line is treated as the filespec of an image to run, and
+an attempt is made to invoke it (using F<.Exe> and the process
+defaults to expand the filespec) and pass the rest of C<exec>'s
+argument to it as parameters. If the token has no file type, and
+matches a file with null type, then an attempt is made to determine
+whether the file is an executable image which should be invoked
+using C<MCR> or a text file which should be passed to DCL as a
+command procedure.
+
+=item fork
+
+While in principle the C<fork> operator could be implemented via
+(and with the same rather severe limitations as) the CRTL C<vfork()>
+routine, and while some internal support to do just that is in
+place, the implementation has never been completed, making C<fork>
+currently unavailable. A true kernel C<fork()> is expected in a
+future version of VMS, and the pseudo-fork based on interpreter
+threads may be available in a future version of Perl on VMS (see
+L<perlfork>). In the meantime, use C<system>, backticks, or piped
+filehandles to create subprocesses.
+
+=item getpwent
+
+=item getpwnam
+
+=item getpwuid
+
+These operators obtain the information described in L<perlfunc>,
+if you have the privileges necessary to retrieve the named user's
+UAF information via C<sys$getuai>. If not, then only the C<$name>,
+C<$uid>, and C<$gid> items are returned. The C<$dir> item contains
+the login directory in VMS syntax, while the C<$comment> item
+contains the login directory in Unix syntax. The C<$gcos> item
+contains the owner field from the UAF record. The C<$quota>
+item is not used.
+
+=item gmtime
+
+The C<gmtime> operator will function properly if you have a
+working CRTL C<gmtime()> routine, or if the logical name
+SYS$TIMEZONE_DIFFERENTIAL is defined as the number of seconds
+which must be added to UTC to yield local time. (This logical
+name is defined automatically if you are running a version of
+VMS with built-in UTC support.) If neither of these cases is
+true, a warning message is printed, and C<undef> is returned.
+
+=item kill
+
+In most cases, C<kill> is implemented via the undocumented system
+service C<$SIGPRC>, which has the same calling sequence as C<$FORCEX>, but
+throws an exception in the target process rather than forcing it to call
+C<$EXIT>. Generally speaking, C<kill> follows the behavior of the
+CRTL's C<kill()> function, but unlike that function can be called from
+within a signal handler. Also, unlike the C<kill> in some versions of
+the CRTL, Perl's C<kill> checks the validity of the signal passed in and
+returns an error rather than attempting to send an unrecognized signal.
+
+Also, negative signal values don't do anything special under
+VMS; they're just converted to the corresponding positive value.
+
+=item qx//
+
+See the entry on C<backticks> above.
+
+=item select (system call)
+
+If Perl was not built with socket support, the system call
+version of C<select> is not available at all. If socket
+support is present, then the system call version of
+C<select> functions only for file descriptors attached
+to sockets. It will not provide information about regular
+files or pipes, since the CRTL C<select()> routine does not
+provide this functionality.
+
+=item stat EXPR
+
+Since VMS keeps track of files according to a different scheme
+than Unix, it's not really possible to represent the file's ID
+in the C<st_dev> and C<st_ino> fields of a C<struct stat>. Perl
+tries its best, though, and the values it uses are pretty unlikely
+to be the same for two different files. We can't guarantee this,
+though, so caveat scriptor.
+
+=item system LIST
+
+The C<system> operator creates a subprocess, and passes its
+arguments to the subprocess for execution as a DCL command.
+Since the subprocess is created directly via C<lib$spawn()>, any
+valid DCL command string may be specified. If the string begins with
+'@', it is treated as a DCL command unconditionally. Otherwise, if
+the first token contains a character used as a delimiter in file
+specification (e.g. C<:> or C<]>), an attempt is made to expand it
+using a default type of F<.Exe> and the process defaults, and if
+successful, the resulting file is invoked via C<MCR>. This allows you
+to invoke an image directly simply by passing the file specification
+to C<system>, a common Unixish idiom. If the token has no file type,
+and matches a file with null type, then an attempt is made to
+determine whether the file is an executable image which should be
+invoked using C<MCR> or a text file which should be passed to DCL
+as a command procedure.
+
+If LIST consists of the empty string, C<system> spawns an
+interactive DCL subprocess, in the same fashion as typing
+B<SPAWN> at the DCL prompt.
+
+Perl waits for the subprocess to complete before continuing
+execution in the current process. As described in L<perlfunc>,
+the return value of C<system> is a fake "status" which follows
+POSIX semantics unless the pragma C<use vmsish 'status'> is in
+effect; see the description of C<$?> in this document for more
+detail.
+
+=item time
+
+The value returned by C<time> is the offset in seconds from
+01-JAN-1970 00:00:00 (just like the CRTL's times() routine), in order
+to make life easier for code coming in from the POSIX/Unix world.
+
+=item times
+
+The array returned by the C<times> operator is divided up
+according to the same rules the CRTL C<times()> routine.
+Therefore, the "system time" elements will always be 0, since
+there is no difference between "user time" and "system" time
+under VMS, and the time accumulated by a subprocess may or may
+not appear separately in the "child time" field, depending on
+whether L<times> keeps track of subprocesses separately. Note
+especially that the VAXCRTL (at least) keeps track only of
+subprocesses spawned using L<fork> and L<exec>; it will not
+accumulate the times of subprocesses spawned via pipes, L<system>,
+or backticks.
+
+=item unlink LIST
+
+C<unlink> will delete the highest version of a file only; in
+order to delete all versions, you need to say
+
+ 1 while unlink LIST;
+
+You may need to make this change to scripts written for a
+Unix system which expect that after a call to C<unlink>,
+no files with the names passed to C<unlink> will exist.
+(Note: This can be changed at compile time; if you
+C<use Config> and C<$Config{'d_unlink_all_versions'}> is
+C<define>, then C<unlink> will delete all versions of a
+file on the first call.)
+
+C<unlink> will delete a file if at all possible, even if it
+requires changing file protection (though it won't try to
+change the protection of the parent directory). You can tell
+whether you've got explicit delete access to a file by using the
+C<VMS::Filespec::candelete> operator. For instance, in order
+to delete only files to which you have delete access, you could
+say something like
+
+ sub safe_unlink {
+ my($file,$num);
+ foreach $file (@_) {
+ next unless VMS::Filespec::candelete($file);
+ $num += unlink $file;
+ }
+ $num;
+ }
+
+(or you could just use C<VMS::Stdio::remove>, if you've installed
+the VMS::Stdio extension distributed with Perl). If C<unlink> has to
+change the file protection to delete the file, and you interrupt it
+in midstream, the file may be left intact, but with a changed ACL
+allowing you delete access.
+
+This behavior of C<unlink> is to be compatible with POSIX behavior
+and not traditional VMS behavior.
+
+=item utime LIST
+
+This operator changes only the modification time of the file (VMS
+revision date) on ODS-2 volumes and ODS-5 volumes without access
+dates enabled. On ODS-5 volumes with access dates enabled, the
+true access time is modified.
+
+=item waitpid PID,FLAGS
+
+If PID is a subprocess started by a piped C<open()> (see L<open>),
+C<waitpid> will wait for that subprocess, and return its final status
+value in C<$?>. If PID is a subprocess created in some other way (e.g.
+SPAWNed before Perl was invoked), C<waitpid> will simply check once per
+second whether the process has completed, and return when it has. (If
+PID specifies a process that isn't a subprocess of the current process,
+and you invoked Perl with the C<-w> switch, a warning will be issued.)
+
+Returns PID on success, -1 on error. The FLAGS argument is ignored
+in all cases.
+
+=back
+
+=head1 Perl variables
+
+The following VMS-specific information applies to the indicated
+"special" Perl variables, in addition to the general information
+in L<perlvar>. Where there is a conflict, this information
+takes precedence.
+
+=over 4
+
+=item %ENV
+
+The operation of the C<%ENV> array depends on the translation
+of the logical name F<PERL_ENV_TABLES>. If defined, it should
+be a search list, each element of which specifies a location
+for C<%ENV> elements. If you tell Perl to read or set the
+element C<$ENV{>I<name>C<}>, then Perl uses the translations of
+F<PERL_ENV_TABLES> as follows:
+
+=over 4
+
+=item CRTL_ENV
+
+This string tells Perl to consult the CRTL's internal C<environ>
+array of key-value pairs, using I<name> as the key. In most cases,
+this contains only a few keys, but if Perl was invoked via the C
+C<exec[lv]e()> function, as is the case for CGI processing by some
+HTTP servers, then the C<environ> array may have been populated by
+the calling program.
+
+=item CLISYM_[LOCAL]
+
+A string beginning with C<CLISYM_>tells Perl to consult the CLI's
+symbol tables, using I<name> as the name of the symbol. When reading
+an element of C<%ENV>, the local symbol table is scanned first, followed
+by the global symbol table.. The characters following C<CLISYM_> are
+significant when an element of C<%ENV> is set or deleted: if the
+complete string is C<CLISYM_LOCAL>, the change is made in the local
+symbol table; otherwise the global symbol table is changed.
+
+=item Any other string
+
+If an element of F<PERL_ENV_TABLES> translates to any other string,
+that string is used as the name of a logical name table, which is
+consulted using I<name> as the logical name. The normal search
+order of access modes is used.
+
+=back
+
+F<PERL_ENV_TABLES> is translated once when Perl starts up; any changes
+you make while Perl is running do not affect the behavior of C<%ENV>.
+If F<PERL_ENV_TABLES> is not defined, then Perl defaults to consulting
+first the logical name tables specified by F<LNM$FILE_DEV>, and then
+the CRTL C<environ> array.
+
+In all operations on %ENV, the key string is treated as if it
+were entirely uppercase, regardless of the case actually
+specified in the Perl expression.
+
+When an element of C<%ENV> is read, the locations to which
+F<PERL_ENV_TABLES> points are checked in order, and the value
+obtained from the first successful lookup is returned. If the
+name of the C<%ENV> element contains a semi-colon, it and
+any characters after it are removed. These are ignored when
+the CRTL C<environ> array or a CLI symbol table is consulted.
+However, the name is looked up in a logical name table, the
+suffix after the semi-colon is treated as the translation index
+to be used for the lookup. This lets you look up successive values
+for search list logical names. For instance, if you say
+
+ $ Define STORY once,upon,a,time,there,was
+ $ perl -e "for ($i = 0; $i <= 6; $i++) " -
+ _$ -e "{ print $ENV{'story;'.$i},' '}"
+
+Perl will print C<ONCE UPON A TIME THERE WAS>, assuming, of course,
+that F<PERL_ENV_TABLES> is set up so that the logical name C<story>
+is found, rather than a CLI symbol or CRTL C<environ> element with
+the same name.
+
+When an element of C<%ENV> is set to a defined string, the
+corresponding definition is made in the location to which the
+first translation of F<PERL_ENV_TABLES> points. If this causes a
+logical name to be created, it is defined in supervisor mode.
+(The same is done if an existing logical name was defined in
+executive or kernel mode; an existing user or supervisor mode
+logical name is reset to the new value.) If the value is an empty
+string, the logical name's translation is defined as a single NUL
+(ASCII 00) character, since a logical name cannot translate to a
+zero-length string. (This restriction does not apply to CLI symbols
+or CRTL C<environ> values; they are set to the empty string.)
+An element of the CRTL C<environ> array can be set only if your
+copy of Perl knows about the CRTL's C<setenv()> function. (This is
+present only in some versions of the DECCRTL; check C<$Config{d_setenv}>
+to see whether your copy of Perl was built with a CRTL that has this
+function.)
+
+When an element of C<%ENV> is set to C<undef>,
+the element is looked up as if it were being read, and if it is
+found, it is deleted. (An item "deleted" from the CRTL C<environ>
+array is set to the empty string; this can only be done if your
+copy of Perl knows about the CRTL C<setenv()> function.) Using
+C<delete> to remove an element from C<%ENV> has a similar effect,
+but after the element is deleted, another attempt is made to
+look up the element, so an inner-mode logical name or a name in
+another location will replace the logical name just deleted.
+In either case, only the first value found searching PERL_ENV_TABLES
+is altered. It is not possible at present to define a search list
+logical name via %ENV.
+
+The element C<$ENV{DEFAULT}> is special: when read, it returns
+Perl's current default device and directory, and when set, it
+resets them, regardless of the definition of F<PERL_ENV_TABLES>.
+It cannot be cleared or deleted; attempts to do so are silently
+ignored.
+
+Note that if you want to pass on any elements of the
+C-local environ array to a subprocess which isn't
+started by fork/exec, or isn't running a C program, you
+can "promote" them to logical names in the current
+process, which will then be inherited by all subprocesses,
+by saying
+
+ foreach my $key (qw[C-local keys you want promoted]) {
+ my $temp = $ENV{$key}; # read from C-local array
+ $ENV{$key} = $temp; # and define as logical name
+ }
+
+(You can't just say C<$ENV{$key} = $ENV{$key}>, since the
+Perl optimizer is smart enough to elide the expression.)
+
+Don't try to clear C<%ENV> by saying C<%ENV = ();>, it will throw
+a fatal error. This is equivalent to doing the following from DCL:
+
+ DELETE/LOGICAL *
+
+You can imagine how bad things would be if, for example, the SYS$MANAGER
+or SYS$SYSTEM logical names were deleted.
+
+At present, the first time you iterate over %ENV using
+C<keys>, or C<values>, you will incur a time penalty as all
+logical names are read, in order to fully populate %ENV.
+Subsequent iterations will not reread logical names, so they
+won't be as slow, but they also won't reflect any changes
+to logical name tables caused by other programs.
+
+You do need to be careful with the logical names representing
+process-permanent files, such as C<SYS$INPUT> and C<SYS$OUTPUT>.
+The translations for these logical names are prepended with a
+two-byte binary value (0x1B 0x00) that needs to be stripped off
+if you wantto use it. (In previous versions of Perl it wasn't
+possible to get the values of these logical names, as the null
+byte acted as an end-of-string marker)
+
+=item $!
+
+The string value of C<$!> is that returned by the CRTL's
+strerror() function, so it will include the VMS message for
+VMS-specific errors. The numeric value of C<$!> is the
+value of C<errno>, except if errno is EVMSERR, in which
+case C<$!> contains the value of vaxc$errno. Setting C<$!>
+always sets errno to the value specified. If this value is
+EVMSERR, it also sets vaxc$errno to 4 (NONAME-F-NOMSG), so
+that the string value of C<$!> won't reflect the VMS error
+message from before C<$!> was set.
+
+=item $^E
+
+This variable provides direct access to VMS status values
+in vaxc$errno, which are often more specific than the
+generic Unix-style error messages in C<$!>. Its numeric value
+is the value of vaxc$errno, and its string value is the
+corresponding VMS message string, as retrieved by sys$getmsg().
+Setting C<$^E> sets vaxc$errno to the value specified.
+
+While Perl attempts to keep the vaxc$errno value to be current, if
+errno is not EVMSERR, it may not be from the current operation.
+
+=item $?
+
+The "status value" returned in C<$?> is synthesized from the
+actual exit status of the subprocess in a way that approximates
+POSIX wait(5) semantics, in order to allow Perl programs to
+portably test for successful completion of subprocesses. The
+low order 8 bits of C<$?> are always 0 under VMS, since the
+termination status of a process may or may not have been
+generated by an exception.
+
+The next 8 bits contain the termination status of the program.
+
+If the child process follows the convention of C programs
+compiled with the _POSIX_EXIT macro set, the status value will
+contain the actual value of 0 to 255 returned by that program
+on a normal exit.
+
+With the _POSIX_EXIT macro set, the Unix exit value of zero is
+represented as a VMS native status of 1, and the Unix values
+from 2 to 255 are encoded by the equation:
+
+ VMS_status = 0x35a000 + (unix_value * 8) + 1.
+
+And in the special case of Unix value 1 the encoding is:
+
+ VMS_status = 0x35a000 + 8 + 2 + 0x10000000.
+
+For other termination statuses, the severity portion of the
+subprocess's exit status is used: if the severity was success or
+informational, these bits are all 0; if the severity was
+warning, they contain a value of 1; if the severity was
+error or fatal error, they contain the actual severity bits,
+which turns out to be a value of 2 for error and 4 for severe_error.
+Fatal is another term for the severe_error status.
+
+As a result, C<$?> will always be zero if the subprocess's exit
+status indicated successful completion, and non-zero if a
+warning or error occurred or a program compliant with encoding
+_POSIX_EXIT values was run and set a status.
+
+How can you tell the difference between a non-zero status that is
+the result of a VMS native error status or an encoded Unix status?
+You can not unless you look at the ${^CHILD_ERROR_NATIVE} value.
+The ${^CHILD_ERROR_NATIVE} value returns the actual VMS status value
+and check the severity bits. If the severity bits are equal to 1,
+then if the numeric value for C<$?> is between 2 and 255 or 0, then
+C<$?> accurately reflects a value passed back from a Unix application.
+If C<$?> is 1, and the severity bits indicate a VMS error (2), then
+C<$?> is from a Unix application exit value.
+
+In practice, Perl scripts that call programs that return _POSIX_EXIT
+type status values will be expecting those values, and programs that
+call traditional VMS programs will either be expecting the previous
+behavior or just checking for a non-zero status.
+
+And success is always the value 0 in all behaviors.
+
+When the actual VMS termination status of the child is an error,
+internally the C<$!> value will be set to the closest Unix errno
+value to that error so that Perl scripts that test for error
+messages will see the expected Unix style error message instead
+of a VMS message.
+
+Conversely, when setting C<$?> in an END block, an attempt is made
+to convert the POSIX value into a native status intelligible to
+the operating system upon exiting Perl. What this boils down to
+is that setting C<$?> to zero results in the generic success value
+SS$_NORMAL, and setting C<$?> to a non-zero value results in the
+generic failure status SS$_ABORT. See also L<perlport/exit>.
+
+With the C<PERL_VMS_POSIX_EXIT> logical name defined as "ENABLE",
+setting C<$?> will cause the new value to be encoded into C<$^E>
+so that either the original parent or child exit status values
+ 0 to 255 can be automatically recovered by C programs expecting
+_POSIX_EXIT behavior. If both a parent and a child exit value are
+non-zero, then it will be assumed that this is actually a VMS native
+status value to be passed through. The special value of 0xFFFF is
+almost a NOOP as it will cause the current native VMS status in the
+C library to become the current native Perl VMS status, and is handled
+this way as it is known to not be a valid native VMS status value.
+It is recommend that only values in the range of normal Unix parent or
+child status numbers, 0 to 255 are used.
+
+The pragma C<use vmsish 'status'> makes C<$?> reflect the actual
+VMS exit status instead of the default emulation of POSIX status
+described above. This pragma also disables the conversion of
+non-zero values to SS$_ABORT when setting C<$?> in an END
+block (but zero will still be converted to SS$_NORMAL).
+
+Do not use the pragma C<use vmsish 'status'> with C<PERL_VMS_POSIX_EXIT>
+enabled, as they are at times requesting conflicting actions and the
+consequence of ignoring this advice will be undefined to allow future
+improvements in the POSIX exit handling.
+
+In general, with C<PERL_VMS_POSIX_EXIT> enabled, more detailed information
+will be availble in the exit status for DCL scripts or other native VMS tools,
+and will give the expected information for Posix programs. It has not been
+made the default in order to preserve backward compatibility.
+
+N.B. Setting C<DECC$FILENAME_UNIX_REPORT> implicitly enables
+C<PERL_VMS_POSIX_EXIT>.
+
+=item $|
+
+Setting C<$|> for an I/O stream causes data to be flushed
+all the way to disk on each write (I<i.e.> not just to
+the underlying RMS buffers for a file). In other words,
+it's equivalent to calling fflush() and fsync() from C.
+
+=back
+
+=head1 Standard modules with VMS-specific differences
+
+=head2 SDBM_File
+
+SDBM_File works properly on VMS. It has, however, one minor
+difference. The database directory file created has a F<.sdbm_dir>
+extension rather than a F<.dir> extension. F<.dir> files are VMS filesystem
+directory files, and using them for other purposes could cause unacceptable
+problems.
+
+=head1 Revision date
+
+Please see the git repository for revision history.
+
+=head1 AUTHOR
+
+Charles Bailey bailey@cor.newman.upenn.edu
+Craig Berry craigberry@mac.com
+Dan Sugalski dan@sidhe.org
+John Malmberg wb8tyw@qsl.net
diff --git a/Master/tlpkg/tlperl/lib/pods/perlvos.pod b/Master/tlpkg/tlperl/lib/pods/perlvos.pod
new file mode 100644
index 00000000000..2283fc19b42
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlvos.pod
@@ -0,0 +1,169 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+README.vos - Perl for Stratus VOS
+
+=head1 SYNOPSIS
+
+This file contains notes for building perl on the Stratus VOS
+operating system. Perl is a scripting or macro language that is
+popular on many systems. See L<perlbook> for a number of good
+books on Perl.
+
+These are instructions for building Perl from source. This version of
+Perl is not supported on VOS Release 14.2 or earlier releases. If you
+have a Continuum platform running VOS Release 14.3 through 14.7,
+download Perl from the Stratus Anonymous FTP site at
+ftp://ftp.stratus.com/pub/vos/posix/ga/continuum/continuum.html. If
+you have a V Series platform running VOS Release 15.0 or later, or if
+you have a V Series platform running OpenVOS Release 17.0 or later,
+download Perl from
+ftp://ftp.stratus.com/pub/vos/posix/ga/v-series/v-series.html. The
+perl distribution files on the Stratus anonymous FTP site are stored
+in a format called a "bundled file". Instructions for unbundling the
+Perl distribution file are at
+ftp://ftp.stratus.com/pub/vos/utility/utility.html.
+
+If you are running VOS Release 14.4.1 or later, you can obtain a
+pre-compiled, supported copy of perl by purchasing Release 2.0.1
+(or later) of the VOS GNU C/C++ and GNU Tools product from
+Stratus Technologies.
+
+=head1 BUILDING PERL FOR VOS
+
+To build perl from its source code on the Stratus Continuum
+platform, you must be have VOS Release 14.5.0 or later, the STCP
+product, and the GNU C/C++ and GNU Tools, Release 2.0.1 or
+later. On the V Series platform you must have VOS Release
+15.0.0 or later, and any version of the GNU C/C++ and GNU Tools
+product.
+
+To build full perl using the supplied Configure script and
+makefiles, change to the "vos" subdirectory and type the command
+"compile_full_perl" or "start_process compile_full_perl". This
+will configure, build, and test perl.
+
+=head1 INSTALLING PERL IN VOS
+
+=over 4
+
+=item 1
+
+If you have built perl using the Configure script, ensure that
+you have modify and default write permission to C<<
+>system>ported >> and all subdirectories. Then type
+
+ gmake install
+
+=item 2
+
+While there are currently no architecture-specific extensions or
+modules distributed with perl, the following directories can be
+used to hold such files (replace the string VERSION by the
+appropriate version number):
+
+ >system>ported>lib>perl5>VERSION>7100
+ >system>ported>lib>perl5>VERSION>8000
+ >system>ported>lib>perl5>VERSION>i786
+
+=item 3
+
+Site-specific perl extensions and modules can be installed in one of
+two places. Put architecture-independent files into:
+
+ >system>ported>lib>perl5>site_perl>VERSION
+
+Put site-specific architecture-dependent files into one of the
+following directories:
+
+ >system>ported>lib>perl5>site_perl>VERSION>7100
+ >system>ported>lib>perl5>site_perl>VERSION>8000
+ >system>ported>lib>perl5>site_perl>VERSION>i786
+
+=item 4
+
+You can examine the @INC variable from within a perl program
+to see the order in which Perl searches these directories.
+
+=back
+
+=head1 USING PERL IN VOS
+
+=head2 Restrictions of Perl on VOS
+
+This port of Perl version 5 to VOS prefers Unix-style,
+slash-separated pathnames over VOS-style greater-than-separated
+pathnames. VOS-style pathnames should work in most contexts, but
+if you have trouble, replace all greater-than characters by slash
+characters. Because the slash character is used as a pathname
+delimiter, Perl cannot process VOS pathnames containing a slash
+character in a directory or file name; these must be renamed.
+
+This port of Perl also uses Unix-epoch date values internally.
+As long as you are dealing with ASCII character string
+representations of dates, this should not be an issue. The
+supported epoch is January 1, 1980 to January 17, 2038.
+
+See the file pod/perlport.pod for more information about the VOS
+port of Perl.
+
+=head2 Handling of underflow and overflow
+
+Prior to VOS Release 14.7.0, VOS does not support automatically
+mapping overflowed floating-point values to +infinity, nor
+automatically mapping underflowed floating-point values to zero,
+unlike many other platforms. The Perl pack function has been
+modified to perform such mapping in software on VOS. Performing
+other floating-point computations that underflow or overflow
+will probably result in SIGFPE. Don't push your luck.
+
+As of VOS Release 14.7.0 or later, the VOS POSIX runtime sets up
+the PA-RISC and IA-32 hardware floating-point status register so
+that the overflow and underflow exceptions do not trap, but
+instead automatically convert the result to infinity or zero, as
+appropriate. As of this writing, there are still floating-point
+operations that can trap, for example, subtracting two infinite
+values. This is recorded as suggestion posix-1022, which has
+been fixed in VOS Release 15.2 and higher.
+
+=head1 TEST STATUS
+
+When Perl 5.9.0 is built using the native build process on VOS
+Release 14.7.0 and GNU C++/GNU Tools 2.0.2a, all but nine
+attempted tests either pass or result in TODO (ignored)
+failures. The tests that fail are:
+
+t/io/dup, test 2
+t/io/tell, test 28
+t/op/pack, test 0
+ext/B/t/bytecode, test 1
+ext/Devel/Peek/t/Peek, test 1
+ext/Encode/t/enc_module, test 1
+ext/IO/t/io_dup, test 2
+lib/ExtUtils/t/MM_Unix, test 94
+lib/Net/ing/t/450_service, test 8
+
+=head1 SUPPORT STATUS
+
+I'm offering this port "as is". You can ask me questions, but I
+can't guarantee I'll be able to answer them. There are some
+excellent books available on the Perl language; consult a book
+seller.
+
+If you want a supported version of perl for VOS, purchase the
+VOS GNU C/C++ and GNU Tools Release 2.0.1 (or later) product from
+Stratus Technologies, along with a support contract (or from
+anyone else who will sell you support).
+
+=head1 AUTHOR
+
+Paul Green (Paul.Green@stratus.com)
+
+=head1 LAST UPDATE
+
+October 6, 2010
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlwin32.pod b/Master/tlpkg/tlperl/lib/pods/perlwin32.pod
new file mode 100644
index 00000000000..f9c3353b6d7
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlwin32.pod
@@ -0,0 +1,1031 @@
+If you read this file _as_is_, just ignore the funny characters you
+see. It is written in the POD format (see pod/perlpod.pod) which is
+specially designed to be readable as is.
+
+=head1 NAME
+
+perlwin32 - Perl under Windows
+
+=head1 SYNOPSIS
+
+These are instructions for building Perl under Windows 9x/NT/2000/XP
+on the Intel x86 and Itanium architectures.
+
+=head1 DESCRIPTION
+
+Before you start, you should glance through the README file
+found in the top-level directory to which the Perl distribution
+was extracted. Make sure you read and understand the terms under
+which this software is being distributed.
+
+Also make sure you read L<BUGS AND CAVEATS> below for the
+known limitations of this port.
+
+The INSTALL file in the perl top-level has much information that is
+only relevant to people building Perl on Unix-like systems. In
+particular, you can safely ignore any information that talks about
+"Configure".
+
+You may also want to look at two other options for building
+a perl that will work on Windows NT: the README.cygwin and
+README.os2 files, each of which give a different set of rules to
+build a Perl that will work on Win32 platforms. Those two methods
+will probably enable you to build a more Unix-compatible perl, but
+you will also need to download and use various other build-time and
+run-time support software described in those files.
+
+This set of instructions is meant to describe a so-called "native"
+port of Perl to Win32 platforms. This includes both 32-bit and
+64-bit Windows operating systems. The resulting Perl requires no
+additional software to run (other than what came with your operating
+system). Currently, this port is capable of using one of the
+following compilers on the Intel x86 architecture:
+
+ Borland C++ version 5.02 or later
+ Microsoft Visual C++ version 2.0 or later
+ MinGW with gcc gcc version 2.95.2 or later
+ Gcc by mingw.org gcc version 2.95.2 or later
+ Gcc by mingw-w64.sf.net gcc version 4.4.3 or later
+
+Note that the last two of these are actually competing projects both
+delivering complete gcc toolchain for MS Windows:
+- http://mingw.org - delivers gcc toolchain targeting 32-bit Windows
+ platform.
+ Use version 3.2.x or later for the best results with this compiler.
+- http://mingw-w64.sf.net - delivers gcc toolchain targeting both 64-bit
+ Windows and 32-bit Windows platforms (despite the project name "mingw-w64"
+ they are not only 64-bit oriented). They deliver the native gcc compilers
+ + cross-compilers that are also supported by perl's makefile.
+
+The Borland C++ and Microsoft Visual C++ compilers are also now being given
+away free. The Borland compiler is available as "Borland C++ Compiler Free
+Command Line Tools" and is the same compiler that ships with the full
+"Borland C++ Builder" product. The Microsoft compiler is available as
+"Visual C++ Toolkit 2003" or "Visual C++ 2005/2008 Express Edition" (and also
+as part of the ".NET Framework SDK") and is the same compiler that ships with
+"Visual C++ .NET 2003 Professional" or "Visual C++ 2005/2008 Professional"
+respectively.
+
+This port can also be built on IA64/AMD64 using:
+
+ Microsoft Platform SDK Nov 2001 (64-bit compiler and tools)
+ MinGW64 compiler (gcc version 4.4.3 or later)
+
+The MS Platform SDK can be downloaded from http://www.microsoft.com/.
+The MinGW64 compiler is available at http://sourceforge.net/projects/mingw-w64.
+The latter is actually a cross-compiler targeting Win64. There's also a trimmed
+down compiler (no java, or gfortran) suitable for building perl available at:
+http://strawberryperl.com/package/kmx/64_gcctoolchain/mingw64-w64-20100123-kmx-v2.zip
+
+NOTE: If you're using a 32-bit compiler to build perl on a 64-bit Windows
+operating system, then you should set the WIN64 environment variable to "undef".
+Also, the trimmed down compiler only passes tests when USE_ITHREADS *= define
+(as opposed to undef) and when the CFG *= Debug line is commented out.
+
+This port fully supports MakeMaker (the set of modules that
+is used to build extensions to perl). Therefore, you should be
+able to build and install most extensions found in the CPAN sites.
+See L<Usage Hints for Perl on Win32> below for general hints about this.
+
+=head2 Setting Up Perl on Win32
+
+=over 4
+
+=item Make
+
+You need a "make" program to build the sources. If you are using
+Visual C++ or the Platform SDK tools under Windows NT/2000/XP, nmake
+will work. All other builds need dmake.
+
+dmake is a freely available make that has very nice macro features
+and parallelability.
+
+A port of dmake for Windows is available from:
+
+ http://search.cpan.org/dist/dmake/
+
+Fetch and install dmake somewhere on your path.
+
+There exists a minor coexistence problem with dmake and Borland C++
+compilers. Namely, if a distribution has C files named with mixed
+case letters, they will be compiled into appropriate .obj-files named
+with all lowercase letters, and every time dmake is invoked
+to bring files up to date, it will try to recompile such files again.
+For example, Tk distribution has a lot of such files, resulting in
+needless recompiles every time dmake is invoked. To avoid this, you
+may use the script "sync_ext.pl" after a successful build. It is
+available in the win32 subdirectory of the Perl source distribution.
+
+=item Command Shell
+
+Use the default "cmd" shell that comes with NT. Some versions of the
+popular 4DOS/NT shell have incompatibilities that may cause you trouble.
+If the build fails under that shell, try building again with the cmd
+shell.
+
+The nmake Makefile also has known incompatibilities with the
+"command.com" shell that comes with Windows 9x. You will need to
+use dmake and makefile.mk to build under Windows 9x.
+
+The surest way to build it is on Windows NT/2000/XP, using the cmd shell.
+
+Make sure the path to the build directory does not contain spaces. The
+build usually works in this circumstance, but some tests will fail.
+
+=item Borland C++
+
+If you are using the Borland compiler, you will need dmake.
+(The make that Borland supplies is seriously crippled and will not
+work for MakeMaker builds.)
+
+See L</"Make"> above.
+
+=item Microsoft Visual C++
+
+The nmake that comes with Visual C++ will suffice for building.
+You will need to run the VCVARS32.BAT file, usually found somewhere
+like C:\MSDEV4.2\BIN or C:\Program Files\Microsoft Visual Studio\VC98\Bin.
+This will set your build environment.
+
+You can also use dmake to build using Visual C++; provided, however,
+you set OSRELEASE to "microsft" (or whatever the directory name
+under which the Visual C dmake configuration lives) in your environment
+and edit win32/config.vc to change "make=nmake" into "make=dmake". The
+latter step is only essential if you want to use dmake as your default
+make for building extensions using MakeMaker.
+
+=item Microsoft Visual C++ 2008 Express Edition
+
+This free version of Visual C++ 2008 Professional contains the same compiler
+and linker that ship with the full version, and also contains everything
+necessary to build Perl, rather than requiring a separate download of the
+Platform SDK like previous versions did.
+
+This package can be downloaded by searching for "Visual Studio 2008 Express
+Edition" in the Download Center at
+http://www.microsoft.com/downloads/search.aspx?displaylang=en. (Providing exact
+links to these packages has proven a pointless task because the links keep on
+changing so often.)
+
+Install Visual C++ 2008, then setup your environment using
+
+ C:\Program Files\Microsoft Visual Studio 9.0\Common7\Tools\vsvars32.bat
+
+(assuming the default installation location was chosen).
+
+Perl should now build using the win32/Makefile. You will need to edit that
+file to set
+
+ CCTYPE = MSVC90FREE
+
+first.
+
+=item Microsoft Visual C++ 2005 Express Edition
+
+This free version of Visual C++ 2005 Professional contains the same compiler
+and linker that ship with the full version, but doesn't contain everything
+necessary to build Perl.
+
+You will also need to download the "Platform SDK" (the "Core SDK" and "MDAC
+SDK" components are required) for more header files and libraries.
+
+These packages can both be downloaded by searching in the Download Center at
+http://www.microsoft.com/downloads/search.aspx?displaylang=en. (Providing exact
+links to these packages has proven a pointless task because the links keep on
+changing so often.)
+
+Try to obtain the latest version of the Platform SDK. Sometimes these packages
+contain a particular Windows OS version in their name, but actually work on
+other OS versions too. For example, the "Windows Server 2003 R2 Platform SDK"
+also runs on Windows XP SP2 and Windows 2000.
+
+According to the download pages these packages are only supported on Windows
+2000/XP/2003, so trying to use these tools on Windows 95/98/ME and even Windows
+NT probably won't work.
+
+Install Visual C++ 2005 first, then the Platform SDK. Setup your environment
+as follows (assuming default installation locations were chosen):
+
+ SET PlatformSDKDir=C:\Program Files\Microsoft Platform SDK
+
+ SET PATH=%SystemRoot%\system32;%SystemRoot%;C:\Program Files\Microsoft Visual Studio 8\Common7\IDE;C:\Program Files\Microsoft Visual Studio 8\VC\BIN;C:\Program Files\Microsoft Visual Studio 8\Common7\Tools;C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\bin;C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727;C:\Program Files\Microsoft Visual Studio 8\VC\VCPackages;%PlatformSDKDir%\Bin
+
+ SET INCLUDE=C:\Program Files\Microsoft Visual Studio 8\VC\INCLUDE;%PlatformSDKDir%\include
+
+ SET LIB=C:\Program Files\Microsoft Visual Studio 8\VC\LIB;C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\lib;%PlatformSDKDir%\lib
+
+ SET LIBPATH=C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727
+
+(The PlatformSDKDir might need to be set differently depending on which version
+you are using. Earlier versions installed into "C:\Program Files\Microsoft SDK",
+while the latest versions install into version-specific locations such as
+"C:\Program Files\Microsoft Platform SDK for Windows Server 2003 R2".)
+
+Perl should now build using the win32/Makefile. You will need to edit that
+file to set
+
+ CCTYPE = MSVC80FREE
+
+and to set CCHOME, CCINCDIR and CCLIBDIR as per the environment setup above.
+
+=item Microsoft Visual C++ Toolkit 2003
+
+This free toolkit contains the same compiler and linker that ship with
+Visual C++ .NET 2003 Professional, but doesn't contain everything
+necessary to build Perl.
+
+You will also need to download the "Platform SDK" (the "Core SDK" and "MDAC
+SDK" components are required) for header files, libraries and rc.exe, and
+".NET Framework SDK" for more libraries and nmake.exe. Note that the latter
+(which also includes the free compiler and linker) requires the ".NET
+Framework Redistributable" to be installed first. This can be downloaded and
+installed separately, but is included in the "Visual C++ Toolkit 2003" anyway.
+
+These packages can all be downloaded by searching in the Download Center at
+http://www.microsoft.com/downloads/search.aspx?displaylang=en. (Providing exact
+links to these packages has proven a pointless task because the links keep on
+changing so often.)
+
+Try to obtain the latest version of the Platform SDK. Sometimes these packages
+contain a particular Windows OS version in their name, but actually work on
+other OS versions too. For example, the "Windows Server 2003 R2 Platform SDK"
+also runs on Windows XP SP2 and Windows 2000.
+
+According to the download pages these packages are only supported on Windows
+2000/XP/2003, so trying to use these tools on Windows 95/98/ME and even Windows
+NT probably won't work.
+
+Install the Toolkit first, then the Platform SDK, then the .NET Framework SDK.
+Setup your environment as follows (assuming default installation locations
+were chosen):
+
+ SET PlatformSDKDir=C:\Program Files\Microsoft Platform SDK
+
+ SET PATH=%SystemRoot%\system32;%SystemRoot%;C:\Program Files\Microsoft Visual C++ Toolkit 2003\bin;%PlatformSDKDir%\Bin;C:\Program Files\Microsoft.NET\SDK\v1.1\Bin
+
+ SET INCLUDE=C:\Program Files\Microsoft Visual C++ Toolkit 2003\include;%PlatformSDKDir%\include;C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include
+
+ SET LIB=C:\Program Files\Microsoft Visual C++ Toolkit 2003\lib;%PlatformSDKDir%\lib;C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\lib
+
+(The PlatformSDKDir might need to be set differently depending on which version
+you are using. Earlier versions installed into "C:\Program Files\Microsoft SDK",
+while the latest versions install into version-specific locations such as
+"C:\Program Files\Microsoft Platform SDK for Windows Server 2003 R2".)
+
+Several required files will still be missing:
+
+=over 4
+
+=item *
+
+cvtres.exe is required by link.exe when using a .res file. It is actually
+installed by the .NET Framework SDK, but into a location such as the
+following:
+
+ C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322
+
+Copy it from there to %PlatformSDKDir%\Bin
+
+=item *
+
+lib.exe is normally used to build libraries, but link.exe with the /lib
+option also works, so change win32/config.vc to use it instead:
+
+Change the line reading:
+
+ ar='lib'
+
+to:
+
+ ar='link /lib'
+
+It may also be useful to create a batch file called lib.bat in
+C:\Program Files\Microsoft Visual C++ Toolkit 2003\bin containing:
+
+ @echo off
+ link /lib %*
+
+for the benefit of any naughty C extension modules that you might want to build
+later which explicitly reference "lib" rather than taking their value from
+$Config{ar}.
+
+=item *
+
+setargv.obj is required to build perlglob.exe (and perl.exe if the USE_SETARGV
+option is enabled). The Platform SDK supplies this object file in source form
+in %PlatformSDKDir%\src\crt. Copy setargv.c, cruntime.h and
+internal.h from there to some temporary location and build setargv.obj using
+
+ cl.exe /c /I. /D_CRTBLD setargv.c
+
+Then copy setargv.obj to %PlatformSDKDir%\lib
+
+Alternatively, if you don't need perlglob.exe and don't need to enable the
+USE_SETARGV option then you can safely just remove all mention of $(GLOBEXE)
+from win32/Makefile and setargv.obj won't be required anyway.
+
+=back
+
+Perl should now build using the win32/Makefile. You will need to edit that
+file to set
+
+ CCTYPE = MSVC70FREE
+
+and to set CCHOME, CCINCDIR and CCLIBDIR as per the environment setup above.
+
+=item Microsoft Platform SDK 64-bit Compiler
+
+The nmake that comes with the Platform SDK will suffice for building
+Perl. Make sure you are building within one of the "Build Environment"
+shells available after you install the Platform SDK from the Start Menu.
+
+=item MinGW release 3 with gcc
+
+The latest release of MinGW at the time of writing is 3.1.0, which contains
+gcc-3.2.3. It can be downloaded here:
+
+ http://www.mingw.org/
+
+Perl also compiles with earlier releases of gcc (2.95.2 and up). See below
+for notes about using earlier versions of MinGW/gcc.
+
+And perl also compiles with gcc-4.3.0 and up, and perhaps even some of the
+earlier 4.x.x versions.
+
+You also need dmake. See L</"Make"> above on how to get it.
+
+=item MinGW release 1 with gcc
+
+The MinGW-1.1 bundle contains gcc-2.95.3.
+
+Make sure you install the binaries that work with MSVCRT.DLL as indicated
+in the README for the GCC bundle. You may need to set up a few environment
+variables (usually ran from a batch file).
+
+There are a couple of problems with the version of gcc-2.95.2-msvcrt.exe
+released 7 November 1999:
+
+=over
+
+=item *
+
+It left out a fix for certain command line quotes. To fix this, be sure
+to download and install the file fixes/quote-fix-msvcrt.exe from the above
+ftp location.
+
+=item *
+
+The definition of the fpos_t type in stdio.h may be wrong. If your
+stdio.h has this problem, you will see an exception when running the
+test t/lib/io_xs.t. To fix this, change the typedef for fpos_t from
+"long" to "long long" in the file i386-mingw32msvc/include/stdio.h,
+and rebuild.
+
+=back
+
+A potentially simpler to install (but probably soon-to-be-outdated) bundle
+of the above package with the mentioned fixes already applied is available
+here:
+
+ http://downloads.ActiveState.com/pub/staff/gsar/gcc-2.95.2-msvcrt.zip
+ ftp://ftp.ActiveState.com/pub/staff/gsar/gcc-2.95.2-msvcrt.zip
+
+=back
+
+=head2 Building
+
+=over 4
+
+=item *
+
+Make sure you are in the "win32" subdirectory under the perl toplevel.
+This directory contains a "Makefile" that will work with
+versions of nmake that come with Visual C++ or the Platform SDK, and
+a dmake "makefile.mk" that will work for all supported compilers. The
+defaults in the dmake makefile are setup to build using MinGW/gcc.
+
+=item *
+
+Edit the makefile.mk (or Makefile, if you're using nmake) and change
+the values of INST_DRV and INST_TOP. You can also enable various
+build flags. These are explained in the makefiles.
+
+Note that it is generally not a good idea to try to build a perl with
+INST_DRV and INST_TOP set to a path that already exists from a previous
+build. In particular, this may cause problems with the
+lib/ExtUtils/t/Embed.t test, which attempts to build a test program and
+may end up building against the installed perl's lib/CORE directory rather
+than the one being tested.
+
+You will have to make sure that CCTYPE is set correctly and that
+CCHOME points to wherever you installed your compiler. If building with
+gcc-4.x.x, you'll also need to uncomment the assignment to GCC_4XX and
+uncomment the assignment to the appropriate GCCHELPERDLL in the makefile.mk.
+
+If building with the cross-compiler provided by
+mingw-w64.sourceforge.net you'll need to uncomment the line that sets
+GCCCROSS in the makefile.mk. Do this only if it's the cross-compiler - ie
+only if the bin folder doesn't contain a gcc.exe. (The cross-compiler
+does not provide a gcc.exe, g++.exe, ar.exe, etc. Instead, all of these
+executables are prefixed with 'x86_64-w64-mingw32-'.)
+
+The default value for CCHOME in the makefiles for Visual C++
+may not be correct for some versions. Make sure the default exists
+and is valid.
+
+You may also need to comment out the C<DELAYLOAD = ...> line in the
+Makefile if you're using VC++ 6.0 without the latest service pack and
+the linker reports an internal error.
+
+If you are using VC++ 4.2 or earlier then you'll have to change the /EHsc
+option in the CXX_FLAG macro to the equivalent /GX option.
+
+If you have either the source or a library that contains des_fcrypt(),
+enable the appropriate option in the makefile. A ready-to-use version
+of fcrypt.c, based on the version originally written by Eric Young at
+ftp://ftp.funet.fi/pub/crypt/mirrors/dsi/libdes/, is bundled with the
+distribution and CRYPT_SRC is set to use it.
+Alternatively, if you have built a library that contains des_fcrypt(),
+you can set CRYPT_LIB to point to the library name.
+Perl will also build without des_fcrypt(), but the crypt() builtin will
+fail at run time.
+
+If you want build some core extensions statically into perl's dll, specify
+them in the STATIC_EXT macro.
+
+Be sure to read the instructions near the top of the makefiles carefully.
+
+=item *
+
+Type "dmake" (or "nmake" if you are using that make).
+
+This should build everything. Specifically, it will create perl.exe,
+perl512.dll at the perl toplevel, and various other extension dll's
+under the lib\auto directory. If the build fails for any reason, make
+sure you have done the previous steps correctly.
+
+=back
+
+=head2 Testing Perl on Win32
+
+Type "dmake test" (or "nmake test"). This will run most of the tests from
+the testsuite (many tests will be skipped).
+
+There should be no test failures when running under Windows NT/2000/XP.
+Many tests I<will> fail under Windows 9x due to the inferior command shell.
+
+Some test failures may occur if you use a command shell other than the
+native "cmd.exe", or if you are building from a path that contains
+spaces. So don't do that.
+
+If you are running the tests from a emacs shell window, you may see
+failures in op/stat.t. Run "dmake test-notty" in that case.
+
+If you're using the Borland compiler, you may see a failure in op/taint.t
+arising from the inability to find the Borland Runtime DLLs on the system
+default path. You will need to copy the DLLs reported by the messages
+from where Borland chose to install it, into the Windows system directory
+(usually somewhere like C:\WINNT\SYSTEM32) and rerun the test.
+
+If you're using Borland compiler versions 5.2 and below, you may run into
+problems finding the correct header files when building extensions. For
+example, building the "Tk" extension may fail because both perl and Tk
+contain a header file called "patchlevel.h". The latest Borland compiler
+(v5.5) is free of this misbehaviour, and it even supports an
+option -VI- for backward (bugward) compatibility for using the old Borland
+search algorithm to locate header files.
+
+If you run the tests on a FAT partition, you may see some failures for
+C<link()> related tests (I<op/write.t>, I<op/stat.t> ...). Testing on
+NTFS avoids these errors.
+
+Furthermore, you should make sure that during C<make test> you do not
+have any GNU tool packages in your path: some toolkits like Unixutils
+include some tools (C<type> for instance) which override the Windows
+ones and makes tests fail. Remove them from your path while testing to
+avoid these errors.
+
+Please report any other failures as described under L<BUGS AND CAVEATS>.
+
+=head2 Installation of Perl on Win32
+
+Type "dmake install" (or "nmake install"). This will put the newly
+built perl and the libraries under whatever C<INST_TOP> points to in the
+Makefile. It will also install the pod documentation under
+C<$INST_TOP\$INST_VER\lib\pod> and HTML versions of the same under
+C<$INST_TOP\$INST_VER\lib\pod\html>.
+
+To use the Perl you just installed you will need to add a new entry to
+your PATH environment variable: C<$INST_TOP\bin>, e.g.
+
+ set PATH=c:\perl\bin;%PATH%
+
+If you opted to uncomment C<INST_VER> and C<INST_ARCH> in the makefile
+then the installation structure is a little more complicated and you will
+need to add two new PATH components instead: C<$INST_TOP\$INST_VER\bin> and
+C<$INST_TOP\$INST_VER\bin\$ARCHNAME>, e.g.
+
+ set PATH=c:\perl\5.6.0\bin;c:\perl\5.6.0\bin\MSWin32-x86;%PATH%
+
+=head2 Usage Hints for Perl on Win32
+
+=over 4
+
+=item Environment Variables
+
+The installation paths that you set during the build get compiled
+into perl, so you don't have to do anything additional to start
+using that perl (except add its location to your PATH variable).
+
+If you put extensions in unusual places, you can set PERL5LIB
+to a list of paths separated by semicolons where you want perl
+to look for libraries. Look for descriptions of other environment
+variables you can set in L<perlrun>.
+
+You can also control the shell that perl uses to run system() and
+backtick commands via PERL5SHELL. See L<perlrun>.
+
+Perl does not depend on the registry, but it can look up certain default
+values if you choose to put them there. Perl attempts to read entries from
+C<HKEY_CURRENT_USER\Software\Perl> and C<HKEY_LOCAL_MACHINE\Software\Perl>.
+Entries in the former override entries in the latter. One or more of the
+following entries (of type REG_SZ or REG_EXPAND_SZ) may be set:
+
+ lib-$] version-specific standard library path to add to @INC
+ lib standard library path to add to @INC
+ sitelib-$] version-specific site library path to add to @INC
+ sitelib site library path to add to @INC
+ vendorlib-$] version-specific vendor library path to add to @INC
+ vendorlib vendor library path to add to @INC
+ PERL* fallback for all %ENV lookups that begin with "PERL"
+
+Note the C<$]> in the above is not literal. Substitute whatever version
+of perl you want to honor that entry, e.g. C<5.6.0>. Paths must be
+separated with semicolons, as usual on win32.
+
+=item File Globbing
+
+By default, perl handles file globbing using the File::Glob extension,
+which provides portable globbing.
+
+If you want perl to use globbing that emulates the quirks of DOS
+filename conventions, you might want to consider using File::DosGlob
+to override the internal glob() implementation. See L<File::DosGlob> for
+details.
+
+=item Using perl from the command line
+
+If you are accustomed to using perl from various command-line
+shells found in UNIX environments, you will be less than pleased
+with what Windows offers by way of a command shell.
+
+The crucial thing to understand about the Windows environment is that
+the command line you type in is processed twice before Perl sees it.
+First, your command shell (usually CMD.EXE on Windows NT, and
+COMMAND.COM on Windows 9x) preprocesses the command line, to handle
+redirection, environment variable expansion, and location of the
+executable to run. Then, the perl executable splits the remaining
+command line into individual arguments, using the C runtime library
+upon which Perl was built.
+
+It is particularly important to note that neither the shell nor the C
+runtime do any wildcard expansions of command-line arguments (so
+wildcards need not be quoted). Also, the quoting behaviours of the
+shell and the C runtime are rudimentary at best (and may, if you are
+using a non-standard shell, be inconsistent). The only (useful) quote
+character is the double quote ("). It can be used to protect spaces
+and other special characters in arguments.
+
+The Windows NT documentation has almost no description of how the
+quoting rules are implemented, but here are some general observations
+based on experiments: The C runtime breaks arguments at spaces and
+passes them to programs in argc/argv. Double quotes can be used to
+prevent arguments with spaces in them from being split up. You can
+put a double quote in an argument by escaping it with a backslash and
+enclosing the whole argument within double quotes. The backslash and
+the pair of double quotes surrounding the argument will be stripped by
+the C runtime.
+
+The file redirection characters "E<lt>", "E<gt>", and "|" can be quoted by
+double quotes (although there are suggestions that this may not always
+be true). Single quotes are not treated as quotes by the shell or
+the C runtime, they don't get stripped by the shell (just to make
+this type of quoting completely useless). The caret "^" has also
+been observed to behave as a quoting character, but this appears
+to be a shell feature, and the caret is not stripped from the command
+line, so Perl still sees it (and the C runtime phase does not treat
+the caret as a quote character).
+
+Here are some examples of usage of the "cmd" shell:
+
+This prints two doublequotes:
+
+ perl -e "print '\"\"' "
+
+This does the same:
+
+ perl -e "print \"\\\"\\\"\" "
+
+This prints "bar" and writes "foo" to the file "blurch":
+
+ perl -e "print 'foo'; print STDERR 'bar'" > blurch
+
+This prints "foo" ("bar" disappears into nowhereland):
+
+ perl -e "print 'foo'; print STDERR 'bar'" 2> nul
+
+This prints "bar" and writes "foo" into the file "blurch":
+
+ perl -e "print 'foo'; print STDERR 'bar'" 1> blurch
+
+This pipes "foo" to the "less" pager and prints "bar" on the console:
+
+ perl -e "print 'foo'; print STDERR 'bar'" | less
+
+This pipes "foo\nbar\n" to the less pager:
+
+ perl -le "print 'foo'; print STDERR 'bar'" 2>&1 | less
+
+This pipes "foo" to the pager and writes "bar" in the file "blurch":
+
+ perl -e "print 'foo'; print STDERR 'bar'" 2> blurch | less
+
+
+Discovering the usefulness of the "command.com" shell on Windows 9x
+is left as an exercise to the reader :)
+
+One particularly pernicious problem with the 4NT command shell for
+Windows NT is that it (nearly) always treats a % character as indicating
+that environment variable expansion is needed. Under this shell, it is
+therefore important to always double any % characters which you want
+Perl to see (for example, for hash variables), even when they are
+quoted.
+
+=item Building Extensions
+
+The Comprehensive Perl Archive Network (CPAN) offers a wealth
+of extensions, some of which require a C compiler to build.
+Look in http://www.cpan.org/ for more information on CPAN.
+
+Note that not all of the extensions available from CPAN may work
+in the Win32 environment; you should check the information at
+http://testers.cpan.org/ before investing too much effort into
+porting modules that don't readily build.
+
+Most extensions (whether they require a C compiler or not) can
+be built, tested and installed with the standard mantra:
+
+ perl Makefile.PL
+ $MAKE
+ $MAKE test
+ $MAKE install
+
+where $MAKE is whatever 'make' program you have configured perl to
+use. Use "perl -V:make" to find out what this is. Some extensions
+may not provide a testsuite (so "$MAKE test" may not do anything or
+fail), but most serious ones do.
+
+It is important that you use a supported 'make' program, and
+ensure Config.pm knows about it. If you don't have nmake, you can
+either get dmake from the location mentioned earlier or get an
+old version of nmake reportedly available from:
+
+ http://download.microsoft.com/download/vc15/Patch/1.52/W95/EN-US/nmake15.exe
+
+Another option is to use the make written in Perl, available from
+CPAN.
+
+ http://www.cpan.org/modules/by-module/Make/
+
+You may also use dmake. See L</"Make"> above on how to get it.
+
+Note that MakeMaker actually emits makefiles with different syntax
+depending on what 'make' it thinks you are using. Therefore, it is
+important that one of the following values appears in Config.pm:
+
+ make='nmake' # MakeMaker emits nmake syntax
+ make='dmake' # MakeMaker emits dmake syntax
+ any other value # MakeMaker emits generic make syntax
+ (e.g GNU make, or Perl make)
+
+If the value doesn't match the 'make' program you want to use,
+edit Config.pm to fix it.
+
+If a module implements XSUBs, you will need one of the supported
+C compilers. You must make sure you have set up the environment for
+the compiler for command-line compilation.
+
+If a module does not build for some reason, look carefully for
+why it failed, and report problems to the module author. If
+it looks like the extension building support is at fault, report
+that with full details of how the build failed using the perlbug
+utility.
+
+=item Command-line Wildcard Expansion
+
+The default command shells on DOS descendant operating systems (such
+as they are) usually do not expand wildcard arguments supplied to
+programs. They consider it the application's job to handle that.
+This is commonly achieved by linking the application (in our case,
+perl) with startup code that the C runtime libraries usually provide.
+However, doing that results in incompatible perl versions (since the
+behavior of the argv expansion code differs depending on the
+compiler, and it is even buggy on some compilers). Besides, it may
+be a source of frustration if you use such a perl binary with an
+alternate shell that *does* expand wildcards.
+
+Instead, the following solution works rather well. The nice things
+about it are 1) you can start using it right away; 2) it is more
+powerful, because it will do the right thing with a pattern like
+*/*/*.c; 3) you can decide whether you do/don't want to use it; and
+4) you can extend the method to add any customizations (or even
+entirely different kinds of wildcard expansion).
+
+ C:\> copy con c:\perl\lib\Wild.pm
+ # Wild.pm - emulate shell @ARGV expansion on shells that don't
+ use File::DosGlob;
+ @ARGV = map {
+ my @g = File::DosGlob::glob($_) if /[*?]/;
+ @g ? @g : $_;
+ } @ARGV;
+ 1;
+ ^Z
+ C:\> set PERL5OPT=-MWild
+ C:\> perl -le "for (@ARGV) { print }" */*/perl*.c
+ p4view/perl/perl.c
+ p4view/perl/perlio.c
+ p4view/perl/perly.c
+ perl5.005/win32/perlglob.c
+ perl5.005/win32/perllib.c
+ perl5.005/win32/perlglob.c
+ perl5.005/win32/perllib.c
+ perl5.005/win32/perlglob.c
+ perl5.005/win32/perllib.c
+
+Note there are two distinct steps there: 1) You'll have to create
+Wild.pm and put it in your perl lib directory. 2) You'll need to
+set the PERL5OPT environment variable. If you want argv expansion
+to be the default, just set PERL5OPT in your default startup
+environment.
+
+If you are using the Visual C compiler, you can get the C runtime's
+command line wildcard expansion built into perl binary. The resulting
+binary will always expand unquoted command lines, which may not be
+what you want if you use a shell that does that for you. The expansion
+done is also somewhat less powerful than the approach suggested above.
+
+=item Win32 Specific Extensions
+
+A number of extensions specific to the Win32 platform are available
+from CPAN. You may find that many of these extensions are meant to
+be used under the Activeware port of Perl, which used to be the only
+native port for the Win32 platform. Since the Activeware port does not
+have adequate support for Perl's extension building tools, these
+extensions typically do not support those tools either and, therefore,
+cannot be built using the generic steps shown in the previous section.
+
+To ensure smooth transitioning of existing code that uses the
+ActiveState port, there is a bundle of Win32 extensions that contains
+all of the ActiveState extensions and several other Win32 extensions from
+CPAN in source form, along with many added bugfixes, and with MakeMaker
+support. The latest version of this bundle is available at:
+
+ http://search.cpan.org/dist/libwin32/
+
+See the README in that distribution for building and installation
+instructions.
+
+=item Notes on 64-bit Windows
+
+Windows .NET Server supports the LLP64 data model on the Intel Itanium
+architecture.
+
+The LLP64 data model is different from the LP64 data model that is the
+norm on 64-bit Unix platforms. In the former, C<int> and C<long> are
+both 32-bit data types, while pointers are 64 bits wide. In addition,
+there is a separate 64-bit wide integral type, C<__int64>. In contrast,
+the LP64 data model that is pervasive on Unix platforms provides C<int>
+as the 32-bit type, while both the C<long> type and pointers are of
+64-bit precision. Note that both models provide for 64-bits of
+addressability.
+
+64-bit Windows running on Itanium is capable of running 32-bit x86
+binaries transparently. This means that you could use a 32-bit build
+of Perl on a 64-bit system. Given this, why would one want to build
+a 64-bit build of Perl? Here are some reasons why you would bother:
+
+=over
+
+=item *
+
+A 64-bit native application will run much more efficiently on
+Itanium hardware.
+
+=item *
+
+There is no 2GB limit on process size.
+
+=item *
+
+Perl automatically provides large file support when built under
+64-bit Windows.
+
+=item *
+
+Embedding Perl inside a 64-bit application.
+
+=back
+
+=back
+
+=head2 Running Perl Scripts
+
+Perl scripts on UNIX use the "#!" (a.k.a "shebang") line to
+indicate to the OS that it should execute the file using perl.
+Win32 has no comparable means to indicate arbitrary files are
+executables.
+
+Instead, all available methods to execute plain text files on
+Win32 rely on the file "extension". There are three methods
+to use this to execute perl scripts:
+
+=over 8
+
+=item 1
+
+There is a facility called "file extension associations" that will
+work in Windows NT 4.0. This can be manipulated via the two
+commands "assoc" and "ftype" that come standard with Windows NT
+4.0. Type "ftype /?" for a complete example of how to set this
+up for perl scripts (Say what? You thought Windows NT wasn't
+perl-ready? :).
+
+=item 2
+
+Since file associations don't work everywhere, and there are
+reportedly bugs with file associations where it does work, the
+old method of wrapping the perl script to make it look like a
+regular batch file to the OS, may be used. The install process
+makes available the "pl2bat.bat" script which can be used to wrap
+perl scripts into batch files. For example:
+
+ pl2bat foo.pl
+
+will create the file "FOO.BAT". Note "pl2bat" strips any
+.pl suffix and adds a .bat suffix to the generated file.
+
+If you use the 4DOS/NT or similar command shell, note that
+"pl2bat" uses the "%*" variable in the generated batch file to
+refer to all the command line arguments, so you may need to make
+sure that construct works in batch files. As of this writing,
+4DOS/NT users will need a "ParameterChar = *" statement in their
+4NT.INI file or will need to execute "setdos /p*" in the 4DOS/NT
+startup file to enable this to work.
+
+=item 3
+
+Using "pl2bat" has a few problems: the file name gets changed,
+so scripts that rely on C<$0> to find what they must do may not
+run properly; running "pl2bat" replicates the contents of the
+original script, and so this process can be maintenance intensive
+if the originals get updated often. A different approach that
+avoids both problems is possible.
+
+A script called "runperl.bat" is available that can be copied
+to any filename (along with the .bat suffix). For example,
+if you call it "foo.bat", it will run the file "foo" when it is
+executed. Since you can run batch files on Win32 platforms simply
+by typing the name (without the extension), this effectively
+runs the file "foo", when you type either "foo" or "foo.bat".
+With this method, "foo.bat" can even be in a different location
+than the file "foo", as long as "foo" is available somewhere on
+the PATH. If your scripts are on a filesystem that allows symbolic
+links, you can even avoid copying "runperl.bat".
+
+Here's a diversion: copy "runperl.bat" to "runperl", and type
+"runperl". Explain the observed behavior, or lack thereof. :)
+Hint: .gnidnats llits er'uoy fi ,"lrepnur" eteled :tniH
+
+=back
+
+=head2 Miscellaneous Things
+
+A full set of HTML documentation is installed, so you should be
+able to use it if you have a web browser installed on your
+system.
+
+C<perldoc> is also a useful tool for browsing information contained
+in the documentation, especially in conjunction with a pager
+like C<less> (recent versions of which have Win32 support). You may
+have to set the PAGER environment variable to use a specific pager.
+"perldoc -f foo" will print information about the perl operator
+"foo".
+
+One common mistake when using this port with a GUI library like C<Tk>
+is assuming that Perl's normal behavior of opening a command-line
+window will go away. This isn't the case. If you want to start a copy
+of C<perl> without opening a command-line window, use the C<wperl>
+executable built during the installation process. Usage is exactly
+the same as normal C<perl> on Win32, except that options like C<-h>
+don't work (since they need a command-line window to print to).
+
+If you find bugs in perl, you can run C<perlbug> to create a
+bug report (you may have to send it manually if C<perlbug> cannot
+find a mailer on your system).
+
+=head1 BUGS AND CAVEATS
+
+Norton AntiVirus interferes with the build process, particularly if
+set to "AutoProtect, All Files, when Opened". Unlike large applications
+the perl build process opens and modifies a lot of files. Having the
+the AntiVirus scan each and every one slows build the process significantly.
+Worse, with PERLIO=stdio the build process fails with peculiar messages
+as the virus checker interacts badly with miniperl.exe writing configure
+files (it seems to either catch file part written and treat it as suspicious,
+or virus checker may have it "locked" in a way which inhibits miniperl
+updating it). The build does complete with
+
+ set PERLIO=perlio
+
+but that may be just luck. Other AntiVirus software may have similar issues.
+
+Some of the built-in functions do not act exactly as documented in
+L<perlfunc>, and a few are not implemented at all. To avoid
+surprises, particularly if you have had prior exposure to Perl
+in other operating environments or if you intend to write code
+that will be portable to other environments, see L<perlport>
+for a reasonably definitive list of these differences.
+
+Not all extensions available from CPAN may build or work properly
+in the Win32 environment. See L</"Building Extensions">.
+
+Most C<socket()> related calls are supported, but they may not
+behave as on Unix platforms. See L<perlport> for the full list.
+Perl requires Winsock2 to be installed on the system. If you're
+running Win95, you can download Winsock upgrade from here:
+
+http://www.microsoft.com/windows95/downloads/contents/WUAdminTools/S_WUNetworkingTools/W95Sockets2/Default.asp
+
+Later OS versions already include Winsock2 support.
+
+Signal handling may not behave as on Unix platforms (where it
+doesn't exactly "behave", either :). For instance, calling C<die()>
+or C<exit()> from signal handlers will cause an exception, since most
+implementations of C<signal()> on Win32 are severely crippled.
+Thus, signals may work only for simple things like setting a flag
+variable in the handler. Using signals under this port should
+currently be considered unsupported.
+
+Please send detailed descriptions of any problems and solutions that
+you may find to E<lt>F<perlbug@perl.org>E<gt>, along with the output
+produced by C<perl -V>.
+
+=head1 ACKNOWLEDGEMENTS
+
+The use of a camel with the topic of Perl is a trademark
+of O'Reilly and Associates, Inc. Used with permission.
+
+=head1 AUTHORS
+
+=over 4
+
+=item Gary Ng E<lt>71564.1743@CompuServe.COME<gt>
+
+=item Gurusamy Sarathy E<lt>gsar@activestate.comE<gt>
+
+=item Nick Ing-Simmons E<lt>nick@ing-simmons.netE<gt>
+
+=item Jan Dubois E<lt>jand@activestate.comE<gt>
+
+=item Steve Hay E<lt>steve.hay@uk.radan.comE<gt>
+
+=back
+
+This document is maintained by Jan Dubois.
+
+=head1 SEE ALSO
+
+L<perl>
+
+=head1 HISTORY
+
+This port was originally contributed by Gary Ng around 5.003_24,
+and borrowed from the Hip Communications port that was available
+at the time. Various people have made numerous and sundry hacks
+since then.
+
+Borland support was added in 5.004_01 (Gurusamy Sarathy).
+
+GCC/mingw32 support was added in 5.005 (Nick Ing-Simmons).
+
+Support for PERL_OBJECT was added in 5.005 (ActiveState Tool Corp).
+
+Support for fork() emulation was added in 5.6 (ActiveState Tool Corp).
+
+Win9x support was added in 5.6 (Benjamin Stuhl).
+
+Support for 64-bit Windows added in 5.8 (ActiveState Corp).
+
+Last updated: 29 August 2007
+
+=cut
diff --git a/Master/tlpkg/tlperl/lib/pods/perlxs.pod b/Master/tlpkg/tlperl/lib/pods/perlxs.pod
new file mode 100644
index 00000000000..5f773bbac32
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlxs.pod
@@ -0,0 +1,2126 @@
+=head1 NAME
+
+perlxs - XS language reference manual
+
+=head1 DESCRIPTION
+
+=head2 Introduction
+
+XS is an interface description file format used to create an extension
+interface between Perl and C code (or a C library) which one wishes
+to use with Perl. The XS interface is combined with the library to
+create a new library which can then be either dynamically loaded
+or statically linked into perl. The XS interface description is
+written in the XS language and is the core component of the Perl
+extension interface.
+
+An B<XSUB> forms the basic unit of the XS interface. After compilation
+by the B<xsubpp> compiler, each XSUB amounts to a C function definition
+which will provide the glue between Perl calling conventions and C
+calling conventions.
+
+The glue code pulls the arguments from the Perl stack, converts these
+Perl values to the formats expected by a C function, call this C function,
+transfers the return values of the C function back to Perl.
+Return values here may be a conventional C return value or any C
+function arguments that may serve as output parameters. These return
+values may be passed back to Perl either by putting them on the
+Perl stack, or by modifying the arguments supplied from the Perl side.
+
+The above is a somewhat simplified view of what really happens. Since
+Perl allows more flexible calling conventions than C, XSUBs may do much
+more in practice, such as checking input parameters for validity,
+throwing exceptions (or returning undef/empty list) if the return value
+from the C function indicates failure, calling different C functions
+based on numbers and types of the arguments, providing an object-oriented
+interface, etc.
+
+Of course, one could write such glue code directly in C. However, this
+would be a tedious task, especially if one needs to write glue for
+multiple C functions, and/or one is not familiar enough with the Perl
+stack discipline and other such arcana. XS comes to the rescue here:
+instead of writing this glue C code in long-hand, one can write
+a more concise short-hand I<description> of what should be done by
+the glue, and let the XS compiler B<xsubpp> handle the rest.
+
+The XS language allows one to describe the mapping between how the C
+routine is used, and how the corresponding Perl routine is used. It
+also allows creation of Perl routines which are directly translated to
+C code and which are not related to a pre-existing C function. In cases
+when the C interface coincides with the Perl interface, the XSUB
+declaration is almost identical to a declaration of a C function (in K&R
+style). In such circumstances, there is another tool called C<h2xs>
+that is able to translate an entire C header file into a corresponding
+XS file that will provide glue to the functions/macros described in
+the header file.
+
+The XS compiler is called B<xsubpp>. This compiler creates
+the constructs necessary to let an XSUB manipulate Perl values, and
+creates the glue necessary to let Perl call the XSUB. The compiler
+uses B<typemaps> to determine how to map C function parameters
+and output values to Perl values and back. The default typemap
+(which comes with Perl) handles many common C types. A supplementary
+typemap may also be needed to handle any special structures and types
+for the library being linked.
+
+A file in XS format starts with a C language section which goes until the
+first C<MODULE =Z<>> directive. Other XS directives and XSUB definitions
+may follow this line. The "language" used in this part of the file
+is usually referred to as the XS language. B<xsubpp> recognizes and
+skips POD (see L<perlpod>) in both the C and XS language sections, which
+allows the XS file to contain embedded documentation.
+
+See L<perlxstut> for a tutorial on the whole extension creation process.
+
+Note: For some extensions, Dave Beazley's SWIG system may provide a
+significantly more convenient mechanism for creating the extension
+glue code. See http://www.swig.org/ for more information.
+
+=head2 On The Road
+
+Many of the examples which follow will concentrate on creating an interface
+between Perl and the ONC+ RPC bind library functions. The rpcb_gettime()
+function is used to demonstrate many features of the XS language. This
+function has two parameters; the first is an input parameter and the second
+is an output parameter. The function also returns a status value.
+
+ bool_t rpcb_gettime(const char *host, time_t *timep);
+
+From C this function will be called with the following
+statements.
+
+ #include <rpc/rpc.h>
+ bool_t status;
+ time_t timep;
+ status = rpcb_gettime( "localhost", &timep );
+
+If an XSUB is created to offer a direct translation between this function
+and Perl, then this XSUB will be used from Perl with the following code.
+The $status and $timep variables will contain the output of the function.
+
+ use RPC;
+ $status = rpcb_gettime( "localhost", $timep );
+
+The following XS file shows an XS subroutine, or XSUB, which
+demonstrates one possible interface to the rpcb_gettime()
+function. This XSUB represents a direct translation between
+C and Perl and so preserves the interface even from Perl.
+This XSUB will be invoked from Perl with the usage shown
+above. Note that the first three #include statements, for
+C<EXTERN.h>, C<perl.h>, and C<XSUB.h>, will always be present at the
+beginning of an XS file. This approach and others will be
+expanded later in this document.
+
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+ #include <rpc/rpc.h>
+
+ MODULE = RPC PACKAGE = RPC
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ OUTPUT:
+ timep
+
+Any extension to Perl, including those containing XSUBs,
+should have a Perl module to serve as the bootstrap which
+pulls the extension into Perl. This module will export the
+extension's functions and variables to the Perl program and
+will cause the extension's XSUBs to be linked into Perl.
+The following module will be used for most of the examples
+in this document and should be used from Perl with the C<use>
+command as shown earlier. Perl modules are explained in
+more detail later in this document.
+
+ package RPC;
+
+ require Exporter;
+ require DynaLoader;
+ @ISA = qw(Exporter DynaLoader);
+ @EXPORT = qw( rpcb_gettime );
+
+ bootstrap RPC;
+ 1;
+
+Throughout this document a variety of interfaces to the rpcb_gettime()
+XSUB will be explored. The XSUBs will take their parameters in different
+orders or will take different numbers of parameters. In each case the
+XSUB is an abstraction between Perl and the real C rpcb_gettime()
+function, and the XSUB must always ensure that the real rpcb_gettime()
+function is called with the correct parameters. This abstraction will
+allow the programmer to create a more Perl-like interface to the C
+function.
+
+=head2 The Anatomy of an XSUB
+
+The simplest XSUBs consist of 3 parts: a description of the return
+value, the name of the XSUB routine and the names of its arguments,
+and a description of types or formats of the arguments.
+
+The following XSUB allows a Perl program to access a C library function
+called sin(). The XSUB will imitate the C function which takes a single
+argument and returns a single value.
+
+ double
+ sin(x)
+ double x
+
+Optionally, one can merge the description of types and the list of
+argument names, rewriting this as
+
+ double
+ sin(double x)
+
+This makes this XSUB look similar to an ANSI C declaration. An optional
+semicolon is allowed after the argument list, as in
+
+ double
+ sin(double x);
+
+Parameters with C pointer types can have different semantic: C functions
+with similar declarations
+
+ bool string_looks_as_a_number(char *s);
+ bool make_char_uppercase(char *c);
+
+are used in absolutely incompatible manner. Parameters to these functions
+could be described B<xsubpp> like this:
+
+ char * s
+ char &c
+
+Both these XS declarations correspond to the C<char*> C type, but they have
+different semantics, see L<"The & Unary Operator">.
+
+It is convenient to think that the indirection operator
+C<*> should be considered as a part of the type and the address operator C<&>
+should be considered part of the variable. See L<"The Typemap">
+for more info about handling qualifiers and unary operators in C types.
+
+The function name and the return type must be placed on
+separate lines and should be flush left-adjusted.
+
+ INCORRECT CORRECT
+
+ double sin(x) double
+ double x sin(x)
+ double x
+
+The rest of the function description may be indented or left-adjusted. The
+following example shows a function with its body left-adjusted. Most
+examples in this document will indent the body for better readability.
+
+ CORRECT
+
+ double
+ sin(x)
+ double x
+
+More complicated XSUBs may contain many other sections. Each section of
+an XSUB starts with the corresponding keyword, such as INIT: or CLEANUP:.
+However, the first two lines of an XSUB always contain the same data:
+descriptions of the return type and the names of the function and its
+parameters. Whatever immediately follows these is considered to be
+an INPUT: section unless explicitly marked with another keyword.
+(See L<The INPUT: Keyword>.)
+
+An XSUB section continues until another section-start keyword is found.
+
+=head2 The Argument Stack
+
+The Perl argument stack is used to store the values which are
+sent as parameters to the XSUB and to store the XSUB's
+return value(s). In reality all Perl functions (including non-XSUB
+ones) keep their values on this stack all the same time, each limited
+to its own range of positions on the stack. In this document the
+first position on that stack which belongs to the active
+function will be referred to as position 0 for that function.
+
+XSUBs refer to their stack arguments with the macro B<ST(x)>, where I<x>
+refers to a position in this XSUB's part of the stack. Position 0 for that
+function would be known to the XSUB as ST(0). The XSUB's incoming
+parameters and outgoing return values always begin at ST(0). For many
+simple cases the B<xsubpp> compiler will generate the code necessary to
+handle the argument stack by embedding code fragments found in the
+typemaps. In more complex cases the programmer must supply the code.
+
+=head2 The RETVAL Variable
+
+The RETVAL variable is a special C variable that is declared automatically
+for you. The C type of RETVAL matches the return type of the C library
+function. The B<xsubpp> compiler will declare this variable in each XSUB
+with non-C<void> return type. By default the generated C function
+will use RETVAL to hold the return value of the C library function being
+called. In simple cases the value of RETVAL will be placed in ST(0) of
+the argument stack where it can be received by Perl as the return value
+of the XSUB.
+
+If the XSUB has a return type of C<void> then the compiler will
+not declare a RETVAL variable for that function. When using
+a PPCODE: section no manipulation of the RETVAL variable is required, the
+section may use direct stack manipulation to place output values on the stack.
+
+If PPCODE: directive is not used, C<void> return value should be used
+only for subroutines which do not return a value, I<even if> CODE:
+directive is used which sets ST(0) explicitly.
+
+Older versions of this document recommended to use C<void> return
+value in such cases. It was discovered that this could lead to
+segfaults in cases when XSUB was I<truly> C<void>. This practice is
+now deprecated, and may be not supported at some future version. Use
+the return value C<SV *> in such cases. (Currently C<xsubpp> contains
+some heuristic code which tries to disambiguate between "truly-void"
+and "old-practice-declared-as-void" functions. Hence your code is at
+mercy of this heuristics unless you use C<SV *> as return value.)
+
+=head2 Returning SVs, AVs and HVs through RETVAL
+
+When you're using RETVAL to return an C<SV *>, there's some magic
+going on behind the scenes that should be mentioned. When you're
+manipulating the argument stack using the ST(x) macro, for example,
+you usually have to pay special attention to reference counts. (For
+more about reference counts, see L<perlguts>.) To make your life
+easier, the typemap file automatically makes C<RETVAL> mortal when
+you're returning an C<SV *>. Thus, the following two XSUBs are more
+or less equivalent:
+
+ void
+ alpha()
+ PPCODE:
+ ST(0) = newSVpv("Hello World",0);
+ sv_2mortal(ST(0));
+ XSRETURN(1);
+
+ SV *
+ beta()
+ CODE:
+ RETVAL = newSVpv("Hello World",0);
+ OUTPUT:
+ RETVAL
+
+This is quite useful as it usually improves readability. While
+this works fine for an C<SV *>, it's unfortunately not as easy
+to have C<AV *> or C<HV *> as a return value. You I<should> be
+able to write:
+
+ AV *
+ array()
+ CODE:
+ RETVAL = newAV();
+ /* do something with RETVAL */
+ OUTPUT:
+ RETVAL
+
+But due to an unfixable bug (fixing it would break lots of existing
+CPAN modules) in the typemap file, the reference count of the C<AV *>
+is not properly decremented. Thus, the above XSUB would leak memory
+whenever it is being called. The same problem exists for C<HV *>.
+
+When you're returning an C<AV *> or a C<HV *>, you have to make sure
+their reference count is decremented by making the AV or HV mortal:
+
+ AV *
+ array()
+ CODE:
+ RETVAL = newAV();
+ sv_2mortal((SV*)RETVAL);
+ /* do something with RETVAL */
+ OUTPUT:
+ RETVAL
+
+And also remember that you don't have to do this for an C<SV *>.
+
+=head2 The MODULE Keyword
+
+The MODULE keyword is used to start the XS code and to specify the package
+of the functions which are being defined. All text preceding the first
+MODULE keyword is considered C code and is passed through to the output with
+POD stripped, but otherwise untouched. Every XS module will have a
+bootstrap function which is used to hook the XSUBs into Perl. The package
+name of this bootstrap function will match the value of the last MODULE
+statement in the XS source files. The value of MODULE should always remain
+constant within the same XS file, though this is not required.
+
+The following example will start the XS code and will place
+all functions in a package named RPC.
+
+ MODULE = RPC
+
+=head2 The PACKAGE Keyword
+
+When functions within an XS source file must be separated into packages
+the PACKAGE keyword should be used. This keyword is used with the MODULE
+keyword and must follow immediately after it when used.
+
+ MODULE = RPC PACKAGE = RPC
+
+ [ XS code in package RPC ]
+
+ MODULE = RPC PACKAGE = RPCB
+
+ [ XS code in package RPCB ]
+
+ MODULE = RPC PACKAGE = RPC
+
+ [ XS code in package RPC ]
+
+The same package name can be used more than once, allowing for
+non-contiguous code. This is useful if you have a stronger ordering
+principle than package names.
+
+Although this keyword is optional and in some cases provides redundant
+information it should always be used. This keyword will ensure that the
+XSUBs appear in the desired package.
+
+=head2 The PREFIX Keyword
+
+The PREFIX keyword designates prefixes which should be
+removed from the Perl function names. If the C function is
+C<rpcb_gettime()> and the PREFIX value is C<rpcb_> then Perl will
+see this function as C<gettime()>.
+
+This keyword should follow the PACKAGE keyword when used.
+If PACKAGE is not used then PREFIX should follow the MODULE
+keyword.
+
+ MODULE = RPC PREFIX = rpc_
+
+ MODULE = RPC PACKAGE = RPCB PREFIX = rpcb_
+
+=head2 The OUTPUT: Keyword
+
+The OUTPUT: keyword indicates that certain function parameters should be
+updated (new values made visible to Perl) when the XSUB terminates or that
+certain values should be returned to the calling Perl function. For
+simple functions which have no CODE: or PPCODE: section,
+such as the sin() function above, the RETVAL variable is
+automatically designated as an output value. For more complex functions
+the B<xsubpp> compiler will need help to determine which variables are output
+variables.
+
+This keyword will normally be used to complement the CODE: keyword.
+The RETVAL variable is not recognized as an output variable when the
+CODE: keyword is present. The OUTPUT: keyword is used in this
+situation to tell the compiler that RETVAL really is an output
+variable.
+
+The OUTPUT: keyword can also be used to indicate that function parameters
+are output variables. This may be necessary when a parameter has been
+modified within the function and the programmer would like the update to
+be seen by Perl.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ OUTPUT:
+ timep
+
+The OUTPUT: keyword will also allow an output parameter to
+be mapped to a matching piece of code rather than to a
+typemap.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ OUTPUT:
+ timep sv_setnv(ST(1), (double)timep);
+
+B<xsubpp> emits an automatic C<SvSETMAGIC()> for all parameters in the
+OUTPUT section of the XSUB, except RETVAL. This is the usually desired
+behavior, as it takes care of properly invoking 'set' magic on output
+parameters (needed for hash or array element parameters that must be
+created if they didn't exist). If for some reason, this behavior is
+not desired, the OUTPUT section may contain a C<SETMAGIC: DISABLE> line
+to disable it for the remainder of the parameters in the OUTPUT section.
+Likewise, C<SETMAGIC: ENABLE> can be used to reenable it for the
+remainder of the OUTPUT section. See L<perlguts> for more details
+about 'set' magic.
+
+=head2 The NO_OUTPUT Keyword
+
+The NO_OUTPUT can be placed as the first token of the XSUB. This keyword
+indicates that while the C subroutine we provide an interface to has
+a non-C<void> return type, the return value of this C subroutine should not
+be returned from the generated Perl subroutine.
+
+With this keyword present L<The RETVAL Variable> is created, and in the
+generated call to the subroutine this variable is assigned to, but the value
+of this variable is not going to be used in the auto-generated code.
+
+This keyword makes sense only if C<RETVAL> is going to be accessed by the
+user-supplied code. It is especially useful to make a function interface
+more Perl-like, especially when the C return value is just an error condition
+indicator. For example,
+
+ NO_OUTPUT int
+ delete_file(char *name)
+ POSTCALL:
+ if (RETVAL != 0)
+ croak("Error %d while deleting file '%s'", RETVAL, name);
+
+Here the generated XS function returns nothing on success, and will die()
+with a meaningful error message on error.
+
+=head2 The CODE: Keyword
+
+This keyword is used in more complicated XSUBs which require
+special handling for the C function. The RETVAL variable is
+still declared, but it will not be returned unless it is specified
+in the OUTPUT: section.
+
+The following XSUB is for a C function which requires special handling of
+its parameters. The Perl usage is given first.
+
+ $status = rpcb_gettime( "localhost", $timep );
+
+The XSUB follows.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t timep
+ CODE:
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+=head2 The INIT: Keyword
+
+The INIT: keyword allows initialization to be inserted into the XSUB before
+the compiler generates the call to the C function. Unlike the CODE: keyword
+above, this keyword does not affect the way the compiler handles RETVAL.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ INIT:
+ printf("# Host is %s\n", host );
+ OUTPUT:
+ timep
+
+Another use for the INIT: section is to check for preconditions before
+making a call to the C function:
+
+ long long
+ lldiv(a,b)
+ long long a
+ long long b
+ INIT:
+ if (a == 0 && b == 0)
+ XSRETURN_UNDEF;
+ if (b == 0)
+ croak("lldiv: cannot divide by 0");
+
+=head2 The NO_INIT Keyword
+
+The NO_INIT keyword is used to indicate that a function
+parameter is being used only as an output value. The B<xsubpp>
+compiler will normally generate code to read the values of
+all function parameters from the argument stack and assign
+them to C variables upon entry to the function. NO_INIT
+will tell the compiler that some parameters will be used for
+output rather than for input and that they will be handled
+before the function terminates.
+
+The following example shows a variation of the rpcb_gettime() function.
+This function uses the timep variable only as an output variable and does
+not care about its initial contents.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep = NO_INIT
+ OUTPUT:
+ timep
+
+=head2 Initializing Function Parameters
+
+C function parameters are normally initialized with their values from
+the argument stack (which in turn contains the parameters that were
+passed to the XSUB from Perl). The typemaps contain the
+code segments which are used to translate the Perl values to
+the C parameters. The programmer, however, is allowed to
+override the typemaps and supply alternate (or additional)
+initialization code. Initialization code starts with the first
+C<=>, C<;> or C<+> on a line in the INPUT: section. The only
+exception happens if this C<;> terminates the line, then this C<;>
+is quietly ignored.
+
+The following code demonstrates how to supply initialization code for
+function parameters. The initialization code is eval'ed within double
+quotes by the compiler before it is added to the output so anything
+which should be interpreted literally [mainly C<$>, C<@>, or C<\\>]
+must be protected with backslashes. The variables $var, $arg,
+and $type can be used as in typemaps.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host = (char *)SvPV_nolen($arg);
+ time_t &timep = 0;
+ OUTPUT:
+ timep
+
+This should not be used to supply default values for parameters. One
+would normally use this when a function parameter must be processed by
+another library function before it can be used. Default parameters are
+covered in the next section.
+
+If the initialization begins with C<=>, then it is output in
+the declaration for the input variable, replacing the initialization
+supplied by the typemap. If the initialization
+begins with C<;> or C<+>, then it is performed after
+all of the input variables have been declared. In the C<;>
+case the initialization normally supplied by the typemap is not performed.
+For the C<+> case, the declaration for the variable will include the
+initialization from the typemap. A global
+variable, C<%v>, is available for the truly rare case where
+information from one initialization is needed in another
+initialization.
+
+Here's a truly obscure example:
+
+ bool_t
+ rpcb_gettime(host,timep)
+ time_t &timep; /* \$v{timep}=@{[$v{timep}=$arg]} */
+ char *host + SvOK($v{timep}) ? SvPV_nolen($arg) : NULL;
+ OUTPUT:
+ timep
+
+The construct C<\$v{timep}=@{[$v{timep}=$arg]}> used in the above
+example has a two-fold purpose: first, when this line is processed by
+B<xsubpp>, the Perl snippet C<$v{timep}=$arg> is evaluated. Second,
+the text of the evaluated snippet is output into the generated C file
+(inside a C comment)! During the processing of C<char *host> line,
+$arg will evaluate to C<ST(0)>, and C<$v{timep}> will evaluate to
+C<ST(1)>.
+
+=head2 Default Parameter Values
+
+Default values for XSUB arguments can be specified by placing an
+assignment statement in the parameter list. The default value may
+be a number, a string or the special string C<NO_INIT>. Defaults should
+always be used on the right-most parameters only.
+
+To allow the XSUB for rpcb_gettime() to have a default host
+value the parameters to the XSUB could be rearranged. The
+XSUB will then call the real rpcb_gettime() function with
+the parameters in the correct order. This XSUB can be called
+from Perl with either of the following statements:
+
+ $status = rpcb_gettime( $timep, $host );
+
+ $status = rpcb_gettime( $timep );
+
+The XSUB will look like the code which follows. A CODE:
+block is used to call the real rpcb_gettime() function with
+the parameters in the correct order for that function.
+
+ bool_t
+ rpcb_gettime(timep,host="localhost")
+ char *host
+ time_t timep = NO_INIT
+ CODE:
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+=head2 The PREINIT: Keyword
+
+The PREINIT: keyword allows extra variables to be declared immediately
+before or after the declarations of the parameters from the INPUT: section
+are emitted.
+
+If a variable is declared inside a CODE: section it will follow any typemap
+code that is emitted for the input parameters. This may result in the
+declaration ending up after C code, which is C syntax error. Similar
+errors may happen with an explicit C<;>-type or C<+>-type initialization of
+parameters is used (see L<"Initializing Function Parameters">). Declaring
+these variables in an INIT: section will not help.
+
+In such cases, to force an additional variable to be declared together
+with declarations of other variables, place the declaration into a
+PREINIT: section. The PREINIT: keyword may be used one or more times
+within an XSUB.
+
+The following examples are equivalent, but if the code is using complex
+typemaps then the first example is safer.
+
+ bool_t
+ rpcb_gettime(timep)
+ time_t timep = NO_INIT
+ PREINIT:
+ char *host = "localhost";
+ CODE:
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+For this particular case an INIT: keyword would generate the
+same C code as the PREINIT: keyword. Another correct, but error-prone example:
+
+ bool_t
+ rpcb_gettime(timep)
+ time_t timep = NO_INIT
+ CODE:
+ char *host = "localhost";
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+Another way to declare C<host> is to use a C block in the CODE: section:
+
+ bool_t
+ rpcb_gettime(timep)
+ time_t timep = NO_INIT
+ CODE:
+ {
+ char *host = "localhost";
+ RETVAL = rpcb_gettime( host, &timep );
+ }
+ OUTPUT:
+ timep
+ RETVAL
+
+The ability to put additional declarations before the typemap entries are
+processed is very handy in the cases when typemap conversions manipulate
+some global state:
+
+ MyObject
+ mutate(o)
+ PREINIT:
+ MyState st = global_state;
+ INPUT:
+ MyObject o;
+ CLEANUP:
+ reset_to(global_state, st);
+
+Here we suppose that conversion to C<MyObject> in the INPUT: section and from
+MyObject when processing RETVAL will modify a global variable C<global_state>.
+After these conversions are performed, we restore the old value of
+C<global_state> (to avoid memory leaks, for example).
+
+There is another way to trade clarity for compactness: INPUT sections allow
+declaration of C variables which do not appear in the parameter list of
+a subroutine. Thus the above code for mutate() can be rewritten as
+
+ MyObject
+ mutate(o)
+ MyState st = global_state;
+ MyObject o;
+ CLEANUP:
+ reset_to(global_state, st);
+
+and the code for rpcb_gettime() can be rewritten as
+
+ bool_t
+ rpcb_gettime(timep)
+ time_t timep = NO_INIT
+ char *host = "localhost";
+ C_ARGS:
+ host, &timep
+ OUTPUT:
+ timep
+ RETVAL
+
+=head2 The SCOPE: Keyword
+
+The SCOPE: keyword allows scoping to be enabled for a particular XSUB. If
+enabled, the XSUB will invoke ENTER and LEAVE automatically.
+
+To support potentially complex type mappings, if a typemap entry used
+by an XSUB contains a comment like C</*scope*/> then scoping will
+be automatically enabled for that XSUB.
+
+To enable scoping:
+
+ SCOPE: ENABLE
+
+To disable scoping:
+
+ SCOPE: DISABLE
+
+=head2 The INPUT: Keyword
+
+The XSUB's parameters are usually evaluated immediately after entering the
+XSUB. The INPUT: keyword can be used to force those parameters to be
+evaluated a little later. The INPUT: keyword can be used multiple times
+within an XSUB and can be used to list one or more input variables. This
+keyword is used with the PREINIT: keyword.
+
+The following example shows how the input parameter C<timep> can be
+evaluated late, after a PREINIT.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ PREINIT:
+ time_t tt;
+ INPUT:
+ time_t timep
+ CODE:
+ RETVAL = rpcb_gettime( host, &tt );
+ timep = tt;
+ OUTPUT:
+ timep
+ RETVAL
+
+The next example shows each input parameter evaluated late.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ PREINIT:
+ time_t tt;
+ INPUT:
+ char *host
+ PREINIT:
+ char *h;
+ INPUT:
+ time_t timep
+ CODE:
+ h = host;
+ RETVAL = rpcb_gettime( h, &tt );
+ timep = tt;
+ OUTPUT:
+ timep
+ RETVAL
+
+Since INPUT sections allow declaration of C variables which do not appear
+in the parameter list of a subroutine, this may be shortened to:
+
+ bool_t
+ rpcb_gettime(host,timep)
+ time_t tt;
+ char *host;
+ char *h = host;
+ time_t timep;
+ CODE:
+ RETVAL = rpcb_gettime( h, &tt );
+ timep = tt;
+ OUTPUT:
+ timep
+ RETVAL
+
+(We used our knowledge that input conversion for C<char *> is a "simple" one,
+thus C<host> is initialized on the declaration line, and our assignment
+C<h = host> is not performed too early. Otherwise one would need to have the
+assignment C<h = host> in a CODE: or INIT: section.)
+
+=head2 The IN/OUTLIST/IN_OUTLIST/OUT/IN_OUT Keywords
+
+In the list of parameters for an XSUB, one can precede parameter names
+by the C<IN>/C<OUTLIST>/C<IN_OUTLIST>/C<OUT>/C<IN_OUT> keywords.
+C<IN> keyword is the default, the other keywords indicate how the Perl
+interface should differ from the C interface.
+
+Parameters preceded by C<OUTLIST>/C<IN_OUTLIST>/C<OUT>/C<IN_OUT>
+keywords are considered to be used by the C subroutine I<via
+pointers>. C<OUTLIST>/C<OUT> keywords indicate that the C subroutine
+does not inspect the memory pointed by this parameter, but will write
+through this pointer to provide additional return values.
+
+Parameters preceded by C<OUTLIST> keyword do not appear in the usage
+signature of the generated Perl function.
+
+Parameters preceded by C<IN_OUTLIST>/C<IN_OUT>/C<OUT> I<do> appear as
+parameters to the Perl function. With the exception of
+C<OUT>-parameters, these parameters are converted to the corresponding
+C type, then pointers to these data are given as arguments to the C
+function. It is expected that the C function will write through these
+pointers.
+
+The return list of the generated Perl function consists of the C return value
+from the function (unless the XSUB is of C<void> return type or
+C<The NO_OUTPUT Keyword> was used) followed by all the C<OUTLIST>
+and C<IN_OUTLIST> parameters (in the order of appearance). On the
+return from the XSUB the C<IN_OUT>/C<OUT> Perl parameter will be
+modified to have the values written by the C function.
+
+For example, an XSUB
+
+ void
+ day_month(OUTLIST day, IN unix_time, OUTLIST month)
+ int day
+ int unix_time
+ int month
+
+should be used from Perl as
+
+ my ($day, $month) = day_month(time);
+
+The C signature of the corresponding function should be
+
+ void day_month(int *day, int unix_time, int *month);
+
+The C<IN>/C<OUTLIST>/C<IN_OUTLIST>/C<IN_OUT>/C<OUT> keywords can be
+mixed with ANSI-style declarations, as in
+
+ void
+ day_month(OUTLIST int day, int unix_time, OUTLIST int month)
+
+(here the optional C<IN> keyword is omitted).
+
+The C<IN_OUT> parameters are identical with parameters introduced with
+L<The & Unary Operator> and put into the C<OUTPUT:> section (see
+L<The OUTPUT: Keyword>). The C<IN_OUTLIST> parameters are very similar,
+the only difference being that the value C function writes through the
+pointer would not modify the Perl parameter, but is put in the output
+list.
+
+The C<OUTLIST>/C<OUT> parameter differ from C<IN_OUTLIST>/C<IN_OUT>
+parameters only by the initial value of the Perl parameter not
+being read (and not being given to the C function - which gets some
+garbage instead). For example, the same C function as above can be
+interfaced with as
+
+ void day_month(OUT int day, int unix_time, OUT int month);
+
+or
+
+ void
+ day_month(day, unix_time, month)
+ int &day = NO_INIT
+ int unix_time
+ int &month = NO_INIT
+ OUTPUT:
+ day
+ month
+
+However, the generated Perl function is called in very C-ish style:
+
+ my ($day, $month);
+ day_month($day, time, $month);
+
+=head2 The C<length(NAME)> Keyword
+
+If one of the input arguments to the C function is the length of a string
+argument C<NAME>, one can substitute the name of the length-argument by
+C<length(NAME)> in the XSUB declaration. This argument must be omitted when
+the generated Perl function is called. E.g.,
+
+ void
+ dump_chars(char *s, short l)
+ {
+ short n = 0;
+ while (n < l) {
+ printf("s[%d] = \"\\%#03o\"\n", n, (int)s[n]);
+ n++;
+ }
+ }
+
+ MODULE = x PACKAGE = x
+
+ void dump_chars(char *s, short length(s))
+
+should be called as C<dump_chars($string)>.
+
+This directive is supported with ANSI-type function declarations only.
+
+=head2 Variable-length Parameter Lists
+
+XSUBs can have variable-length parameter lists by specifying an ellipsis
+C<(...)> in the parameter list. This use of the ellipsis is similar to that
+found in ANSI C. The programmer is able to determine the number of
+arguments passed to the XSUB by examining the C<items> variable which the
+B<xsubpp> compiler supplies for all XSUBs. By using this mechanism one can
+create an XSUB which accepts a list of parameters of unknown length.
+
+The I<host> parameter for the rpcb_gettime() XSUB can be
+optional so the ellipsis can be used to indicate that the
+XSUB will take a variable number of parameters. Perl should
+be able to call this XSUB with either of the following statements.
+
+ $status = rpcb_gettime( $timep, $host );
+
+ $status = rpcb_gettime( $timep );
+
+The XS code, with ellipsis, follows.
+
+ bool_t
+ rpcb_gettime(timep, ...)
+ time_t timep = NO_INIT
+ PREINIT:
+ char *host = "localhost";
+ CODE:
+ if( items > 1 )
+ host = (char *)SvPV_nolen(ST(1));
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+=head2 The C_ARGS: Keyword
+
+The C_ARGS: keyword allows creating of XSUBS which have different
+calling sequence from Perl than from C, without a need to write
+CODE: or PPCODE: section. The contents of the C_ARGS: paragraph is
+put as the argument to the called C function without any change.
+
+For example, suppose that a C function is declared as
+
+ symbolic nth_derivative(int n, symbolic function, int flags);
+
+and that the default flags are kept in a global C variable
+C<default_flags>. Suppose that you want to create an interface which
+is called as
+
+ $second_deriv = $function->nth_derivative(2);
+
+To do this, declare the XSUB as
+
+ symbolic
+ nth_derivative(function, n)
+ symbolic function
+ int n
+ C_ARGS:
+ n, function, default_flags
+
+=head2 The PPCODE: Keyword
+
+The PPCODE: keyword is an alternate form of the CODE: keyword and is used
+to tell the B<xsubpp> compiler that the programmer is supplying the code to
+control the argument stack for the XSUBs return values. Occasionally one
+will want an XSUB to return a list of values rather than a single value.
+In these cases one must use PPCODE: and then explicitly push the list of
+values on the stack. The PPCODE: and CODE: keywords should not be used
+together within the same XSUB.
+
+The actual difference between PPCODE: and CODE: sections is in the
+initialization of C<SP> macro (which stands for the I<current> Perl
+stack pointer), and in the handling of data on the stack when returning
+from an XSUB. In CODE: sections SP preserves the value which was on
+entry to the XSUB: SP is on the function pointer (which follows the
+last parameter). In PPCODE: sections SP is moved backward to the
+beginning of the parameter list, which allows C<PUSH*()> macros
+to place output values in the place Perl expects them to be when
+the XSUB returns back to Perl.
+
+The generated trailer for a CODE: section ensures that the number of return
+values Perl will see is either 0 or 1 (depending on the C<void>ness of the
+return value of the C function, and heuristics mentioned in
+L<"The RETVAL Variable">). The trailer generated for a PPCODE: section
+is based on the number of return values and on the number of times
+C<SP> was updated by C<[X]PUSH*()> macros.
+
+Note that macros C<ST(i)>, C<XST_m*()> and C<XSRETURN*()> work equally
+well in CODE: sections and PPCODE: sections.
+
+The following XSUB will call the C rpcb_gettime() function
+and will return its two output values, timep and status, to
+Perl as a single list.
+
+ void
+ rpcb_gettime(host)
+ char *host
+ PREINIT:
+ time_t timep;
+ bool_t status;
+ PPCODE:
+ status = rpcb_gettime( host, &timep );
+ EXTEND(SP, 2);
+ PUSHs(sv_2mortal(newSViv(status)));
+ PUSHs(sv_2mortal(newSViv(timep)));
+
+Notice that the programmer must supply the C code necessary
+to have the real rpcb_gettime() function called and to have
+the return values properly placed on the argument stack.
+
+The C<void> return type for this function tells the B<xsubpp> compiler that
+the RETVAL variable is not needed or used and that it should not be created.
+In most scenarios the void return type should be used with the PPCODE:
+directive.
+
+The EXTEND() macro is used to make room on the argument
+stack for 2 return values. The PPCODE: directive causes the
+B<xsubpp> compiler to create a stack pointer available as C<SP>, and it
+is this pointer which is being used in the EXTEND() macro.
+The values are then pushed onto the stack with the PUSHs()
+macro.
+
+Now the rpcb_gettime() function can be used from Perl with
+the following statement.
+
+ ($status, $timep) = rpcb_gettime("localhost");
+
+When handling output parameters with a PPCODE section, be sure to handle
+'set' magic properly. See L<perlguts> for details about 'set' magic.
+
+=head2 Returning Undef And Empty Lists
+
+Occasionally the programmer will want to return simply
+C<undef> or an empty list if a function fails rather than a
+separate status value. The rpcb_gettime() function offers
+just this situation. If the function succeeds we would like
+to have it return the time and if it fails we would like to
+have undef returned. In the following Perl code the value
+of $timep will either be undef or it will be a valid time.
+
+ $timep = rpcb_gettime( "localhost" );
+
+The following XSUB uses the C<SV *> return type as a mnemonic only,
+and uses a CODE: block to indicate to the compiler
+that the programmer has supplied all the necessary code. The
+sv_newmortal() call will initialize the return value to undef, making that
+the default return value.
+
+ SV *
+ rpcb_gettime(host)
+ char * host
+ PREINIT:
+ time_t timep;
+ bool_t x;
+ CODE:
+ ST(0) = sv_newmortal();
+ if( rpcb_gettime( host, &timep ) )
+ sv_setnv( ST(0), (double)timep);
+
+The next example demonstrates how one would place an explicit undef in the
+return value, should the need arise.
+
+ SV *
+ rpcb_gettime(host)
+ char * host
+ PREINIT:
+ time_t timep;
+ bool_t x;
+ CODE:
+ if( rpcb_gettime( host, &timep ) ){
+ ST(0) = sv_newmortal();
+ sv_setnv( ST(0), (double)timep);
+ }
+ else{
+ ST(0) = &PL_sv_undef;
+ }
+
+To return an empty list one must use a PPCODE: block and
+then not push return values on the stack.
+
+ void
+ rpcb_gettime(host)
+ char *host
+ PREINIT:
+ time_t timep;
+ PPCODE:
+ if( rpcb_gettime( host, &timep ) )
+ PUSHs(sv_2mortal(newSViv(timep)));
+ else{
+ /* Nothing pushed on stack, so an empty
+ * list is implicitly returned. */
+ }
+
+Some people may be inclined to include an explicit C<return> in the above
+XSUB, rather than letting control fall through to the end. In those
+situations C<XSRETURN_EMPTY> should be used, instead. This will ensure that
+the XSUB stack is properly adjusted. Consult L<perlapi> for other
+C<XSRETURN> macros.
+
+Since C<XSRETURN_*> macros can be used with CODE blocks as well, one can
+rewrite this example as:
+
+ int
+ rpcb_gettime(host)
+ char *host
+ PREINIT:
+ time_t timep;
+ CODE:
+ RETVAL = rpcb_gettime( host, &timep );
+ if (RETVAL == 0)
+ XSRETURN_UNDEF;
+ OUTPUT:
+ RETVAL
+
+In fact, one can put this check into a POSTCALL: section as well. Together
+with PREINIT: simplifications, this leads to:
+
+ int
+ rpcb_gettime(host)
+ char *host
+ time_t timep;
+ POSTCALL:
+ if (RETVAL == 0)
+ XSRETURN_UNDEF;
+
+=head2 The REQUIRE: Keyword
+
+The REQUIRE: keyword is used to indicate the minimum version of the
+B<xsubpp> compiler needed to compile the XS module. An XS module which
+contains the following statement will compile with only B<xsubpp> version
+1.922 or greater:
+
+ REQUIRE: 1.922
+
+=head2 The CLEANUP: Keyword
+
+This keyword can be used when an XSUB requires special cleanup procedures
+before it terminates. When the CLEANUP: keyword is used it must follow
+any CODE:, PPCODE:, or OUTPUT: blocks which are present in the XSUB. The
+code specified for the cleanup block will be added as the last statements
+in the XSUB.
+
+=head2 The POSTCALL: Keyword
+
+This keyword can be used when an XSUB requires special procedures
+executed after the C subroutine call is performed. When the POSTCALL:
+keyword is used it must precede OUTPUT: and CLEANUP: blocks which are
+present in the XSUB.
+
+See examples in L<"The NO_OUTPUT Keyword"> and L<"Returning Undef And Empty Lists">.
+
+The POSTCALL: block does not make a lot of sense when the C subroutine
+call is supplied by user by providing either CODE: or PPCODE: section.
+
+=head2 The BOOT: Keyword
+
+The BOOT: keyword is used to add code to the extension's bootstrap
+function. The bootstrap function is generated by the B<xsubpp> compiler and
+normally holds the statements necessary to register any XSUBs with Perl.
+With the BOOT: keyword the programmer can tell the compiler to add extra
+statements to the bootstrap function.
+
+This keyword may be used any time after the first MODULE keyword and should
+appear on a line by itself. The first blank line after the keyword will
+terminate the code block.
+
+ BOOT:
+ # The following message will be printed when the
+ # bootstrap function executes.
+ printf("Hello from the bootstrap!\n");
+
+=head2 The VERSIONCHECK: Keyword
+
+The VERSIONCHECK: keyword corresponds to B<xsubpp>'s C<-versioncheck> and
+C<-noversioncheck> options. This keyword overrides the command line
+options. Version checking is enabled by default. When version checking is
+enabled the XS module will attempt to verify that its version matches the
+version of the PM module.
+
+To enable version checking:
+
+ VERSIONCHECK: ENABLE
+
+To disable version checking:
+
+ VERSIONCHECK: DISABLE
+
+Note that if the version of the PM module is an NV (a floating point
+number), it will be stringified with a possible loss of precision
+(currently chopping to nine decimal places) so that it may not match
+the version of the XS module anymore. Quoting the $VERSION declaration
+to make it a string is recommended if long version numbers are used.
+
+=head2 The PROTOTYPES: Keyword
+
+The PROTOTYPES: keyword corresponds to B<xsubpp>'s C<-prototypes> and
+C<-noprototypes> options. This keyword overrides the command line options.
+Prototypes are enabled by default. When prototypes are enabled XSUBs will
+be given Perl prototypes. This keyword may be used multiple times in an XS
+module to enable and disable prototypes for different parts of the module.
+
+To enable prototypes:
+
+ PROTOTYPES: ENABLE
+
+To disable prototypes:
+
+ PROTOTYPES: DISABLE
+
+=head2 The PROTOTYPE: Keyword
+
+This keyword is similar to the PROTOTYPES: keyword above but can be used to
+force B<xsubpp> to use a specific prototype for the XSUB. This keyword
+overrides all other prototype options and keywords but affects only the
+current XSUB. Consult L<perlsub/Prototypes> for information about Perl
+prototypes.
+
+ bool_t
+ rpcb_gettime(timep, ...)
+ time_t timep = NO_INIT
+ PROTOTYPE: $;$
+ PREINIT:
+ char *host = "localhost";
+ CODE:
+ if( items > 1 )
+ host = (char *)SvPV_nolen(ST(1));
+ RETVAL = rpcb_gettime( host, &timep );
+ OUTPUT:
+ timep
+ RETVAL
+
+If the prototypes are enabled, you can disable it locally for a given
+XSUB as in the following example:
+
+ void
+ rpcb_gettime_noproto()
+ PROTOTYPE: DISABLE
+ ...
+
+=head2 The ALIAS: Keyword
+
+The ALIAS: keyword allows an XSUB to have two or more unique Perl names
+and to know which of those names was used when it was invoked. The Perl
+names may be fully-qualified with package names. Each alias is given an
+index. The compiler will setup a variable called C<ix> which contain the
+index of the alias which was used. When the XSUB is called with its
+declared name C<ix> will be 0.
+
+The following example will create aliases C<FOO::gettime()> and
+C<BAR::getit()> for this function.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ ALIAS:
+ FOO::gettime = 1
+ BAR::getit = 2
+ INIT:
+ printf("# ix = %d\n", ix );
+ OUTPUT:
+ timep
+
+=head2 The OVERLOAD: Keyword
+
+Instead of writing an overloaded interface using pure Perl, you
+can also use the OVERLOAD keyword to define additional Perl names
+for your functions (like the ALIAS: keyword above). However, the
+overloaded functions must be defined with three parameters (except
+for the nomethod() function which needs four parameters). If any
+function has the OVERLOAD: keyword, several additional lines
+will be defined in the c file generated by xsubpp in order to
+register with the overload magic.
+
+Since blessed objects are actually stored as RV's, it is useful
+to use the typemap features to preprocess parameters and extract
+the actual SV stored within the blessed RV. See the sample for
+T_PTROBJ_SPECIAL below.
+
+To use the OVERLOAD: keyword, create an XS function which takes
+three input parameters ( or use the c style '...' definition) like
+this:
+
+ SV *
+ cmp (lobj, robj, swap)
+ My_Module_obj lobj
+ My_Module_obj robj
+ IV swap
+ OVERLOAD: cmp <=>
+ { /* function defined here */}
+
+In this case, the function will overload both of the three way
+comparison operators. For all overload operations using non-alpha
+characters, you must type the parameter without quoting, separating
+multiple overloads with whitespace. Note that "" (the stringify
+overload) should be entered as \"\" (i.e. escaped).
+
+=head2 The FALLBACK: Keyword
+
+In addition to the OVERLOAD keyword, if you need to control how
+Perl autogenerates missing overloaded operators, you can set the
+FALLBACK keyword in the module header section, like this:
+
+ MODULE = RPC PACKAGE = RPC
+
+ FALLBACK: TRUE
+ ...
+
+where FALLBACK can take any of the three values TRUE, FALSE, or
+UNDEF. If you do not set any FALLBACK value when using OVERLOAD,
+it defaults to UNDEF. FALLBACK is not used except when one or
+more functions using OVERLOAD have been defined. Please see
+L<overload/Fallback> for more details.
+
+=head2 The INTERFACE: Keyword
+
+This keyword declares the current XSUB as a keeper of the given
+calling signature. If some text follows this keyword, it is
+considered as a list of functions which have this signature, and
+should be attached to the current XSUB.
+
+For example, if you have 4 C functions multiply(), divide(), add(),
+subtract() all having the signature:
+
+ symbolic f(symbolic, symbolic);
+
+you can make them all to use the same XSUB using this:
+
+ symbolic
+ interface_s_ss(arg1, arg2)
+ symbolic arg1
+ symbolic arg2
+ INTERFACE:
+ multiply divide
+ add subtract
+
+(This is the complete XSUB code for 4 Perl functions!) Four generated
+Perl function share names with corresponding C functions.
+
+The advantage of this approach comparing to ALIAS: keyword is that there
+is no need to code a switch statement, each Perl function (which shares
+the same XSUB) knows which C function it should call. Additionally, one
+can attach an extra function remainder() at runtime by using
+
+ CV *mycv = newXSproto("Symbolic::remainder",
+ XS_Symbolic_interface_s_ss, __FILE__, "$$");
+ XSINTERFACE_FUNC_SET(mycv, remainder);
+
+say, from another XSUB. (This example supposes that there was no
+INTERFACE_MACRO: section, otherwise one needs to use something else instead of
+C<XSINTERFACE_FUNC_SET>, see the next section.)
+
+=head2 The INTERFACE_MACRO: Keyword
+
+This keyword allows one to define an INTERFACE using a different way
+to extract a function pointer from an XSUB. The text which follows
+this keyword should give the name of macros which would extract/set a
+function pointer. The extractor macro is given return type, C<CV*>,
+and C<XSANY.any_dptr> for this C<CV*>. The setter macro is given cv,
+and the function pointer.
+
+The default value is C<XSINTERFACE_FUNC> and C<XSINTERFACE_FUNC_SET>.
+An INTERFACE keyword with an empty list of functions can be omitted if
+INTERFACE_MACRO keyword is used.
+
+Suppose that in the previous example functions pointers for
+multiply(), divide(), add(), subtract() are kept in a global C array
+C<fp[]> with offsets being C<multiply_off>, C<divide_off>, C<add_off>,
+C<subtract_off>. Then one can use
+
+ #define XSINTERFACE_FUNC_BYOFFSET(ret,cv,f) \
+ ((XSINTERFACE_CVT_ANON(ret))fp[CvXSUBANY(cv).any_i32])
+ #define XSINTERFACE_FUNC_BYOFFSET_set(cv,f) \
+ CvXSUBANY(cv).any_i32 = CAT2( f, _off )
+
+in C section,
+
+ symbolic
+ interface_s_ss(arg1, arg2)
+ symbolic arg1
+ symbolic arg2
+ INTERFACE_MACRO:
+ XSINTERFACE_FUNC_BYOFFSET
+ XSINTERFACE_FUNC_BYOFFSET_set
+ INTERFACE:
+ multiply divide
+ add subtract
+
+in XSUB section.
+
+=head2 The INCLUDE: Keyword
+
+This keyword can be used to pull other files into the XS module. The other
+files may have XS code. INCLUDE: can also be used to run a command to
+generate the XS code to be pulled into the module.
+
+The file F<Rpcb1.xsh> contains our C<rpcb_gettime()> function:
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ OUTPUT:
+ timep
+
+The XS module can use INCLUDE: to pull that file into it.
+
+ INCLUDE: Rpcb1.xsh
+
+If the parameters to the INCLUDE: keyword are followed by a pipe (C<|>) then
+the compiler will interpret the parameters as a command.
+
+ INCLUDE: cat Rpcb1.xsh |
+
+=head2 The CASE: Keyword
+
+The CASE: keyword allows an XSUB to have multiple distinct parts with each
+part acting as a virtual XSUB. CASE: is greedy and if it is used then all
+other XS keywords must be contained within a CASE:. This means nothing may
+precede the first CASE: in the XSUB and anything following the last CASE: is
+included in that case.
+
+A CASE: might switch via a parameter of the XSUB, via the C<ix> ALIAS:
+variable (see L<"The ALIAS: Keyword">), or maybe via the C<items> variable
+(see L<"Variable-length Parameter Lists">). The last CASE: becomes the
+B<default> case if it is not associated with a conditional. The following
+example shows CASE switched via C<ix> with a function C<rpcb_gettime()>
+having an alias C<x_gettime()>. When the function is called as
+C<rpcb_gettime()> its parameters are the usual C<(char *host, time_t *timep)>,
+but when the function is called as C<x_gettime()> its parameters are
+reversed, C<(time_t *timep, char *host)>.
+
+ long
+ rpcb_gettime(a,b)
+ CASE: ix == 1
+ ALIAS:
+ x_gettime = 1
+ INPUT:
+ # 'a' is timep, 'b' is host
+ char *b
+ time_t a = NO_INIT
+ CODE:
+ RETVAL = rpcb_gettime( b, &a );
+ OUTPUT:
+ a
+ RETVAL
+ CASE:
+ # 'a' is host, 'b' is timep
+ char *a
+ time_t &b = NO_INIT
+ OUTPUT:
+ b
+ RETVAL
+
+That function can be called with either of the following statements. Note
+the different argument lists.
+
+ $status = rpcb_gettime( $host, $timep );
+
+ $status = x_gettime( $timep, $host );
+
+=head2 The & Unary Operator
+
+The C<&> unary operator in the INPUT: section is used to tell B<xsubpp>
+that it should convert a Perl value to/from C using the C type to the left
+of C<&>, but provide a pointer to this value when the C function is called.
+
+This is useful to avoid a CODE: block for a C function which takes a parameter
+by reference. Typically, the parameter should be not a pointer type (an
+C<int> or C<long> but not an C<int*> or C<long*>).
+
+The following XSUB will generate incorrect C code. The B<xsubpp> compiler will
+turn this into code which calls C<rpcb_gettime()> with parameters C<(char
+*host, time_t timep)>, but the real C<rpcb_gettime()> wants the C<timep>
+parameter to be of type C<time_t*> rather than C<time_t>.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t timep
+ OUTPUT:
+ timep
+
+That problem is corrected by using the C<&> operator. The B<xsubpp> compiler
+will now turn this into code which calls C<rpcb_gettime()> correctly with
+parameters C<(char *host, time_t *timep)>. It does this by carrying the
+C<&> through, so the function call looks like C<rpcb_gettime(host, &timep)>.
+
+ bool_t
+ rpcb_gettime(host,timep)
+ char *host
+ time_t &timep
+ OUTPUT:
+ timep
+
+=head2 Inserting POD, Comments and C Preprocessor Directives
+
+C preprocessor directives are allowed within BOOT:, PREINIT: INIT:, CODE:,
+PPCODE:, POSTCALL:, and CLEANUP: blocks, as well as outside the functions.
+Comments are allowed anywhere after the MODULE keyword. The compiler will
+pass the preprocessor directives through untouched and will remove the
+commented lines. POD documentation is allowed at any point, both in the
+C and XS language sections. POD must be terminated with a C<=cut> command;
+C<xsubpp> will exit with an error if it does not. It is very unlikely that
+human generated C code will be mistaken for POD, as most indenting styles
+result in whitespace in front of any line starting with C<=>. Machine
+generated XS files may fall into this trap unless care is taken to
+ensure that a space breaks the sequence "\n=".
+
+Comments can be added to XSUBs by placing a C<#> as the first
+non-whitespace of a line. Care should be taken to avoid making the
+comment look like a C preprocessor directive, lest it be interpreted as
+such. The simplest way to prevent this is to put whitespace in front of
+the C<#>.
+
+If you use preprocessor directives to choose one of two
+versions of a function, use
+
+ #if ... version1
+ #else /* ... version2 */
+ #endif
+
+and not
+
+ #if ... version1
+ #endif
+ #if ... version2
+ #endif
+
+because otherwise B<xsubpp> will believe that you made a duplicate
+definition of the function. Also, put a blank line before the
+#else/#endif so it will not be seen as part of the function body.
+
+=head2 Using XS With C++
+
+If an XSUB name contains C<::>, it is considered to be a C++ method.
+The generated Perl function will assume that
+its first argument is an object pointer. The object pointer
+will be stored in a variable called THIS. The object should
+have been created by C++ with the new() function and should
+be blessed by Perl with the sv_setref_pv() macro. The
+blessing of the object by Perl can be handled by a typemap. An example
+typemap is shown at the end of this section.
+
+If the return type of the XSUB includes C<static>, the method is considered
+to be a static method. It will call the C++
+function using the class::method() syntax. If the method is not static
+the function will be called using the THIS-E<gt>method() syntax.
+
+The next examples will use the following C++ class.
+
+ class color {
+ public:
+ color();
+ ~color();
+ int blue();
+ void set_blue( int );
+
+ private:
+ int c_blue;
+ };
+
+The XSUBs for the blue() and set_blue() methods are defined with the class
+name but the parameter for the object (THIS, or "self") is implicit and is
+not listed.
+
+ int
+ color::blue()
+
+ void
+ color::set_blue( val )
+ int val
+
+Both Perl functions will expect an object as the first parameter. In the
+generated C++ code the object is called C<THIS>, and the method call will
+be performed on this object. So in the C++ code the blue() and set_blue()
+methods will be called as this:
+
+ RETVAL = THIS->blue();
+
+ THIS->set_blue( val );
+
+You could also write a single get/set method using an optional argument:
+
+ int
+ color::blue( val = NO_INIT )
+ int val
+ PROTOTYPE $;$
+ CODE:
+ if (items > 1)
+ THIS->set_blue( val );
+ RETVAL = THIS->blue();
+ OUTPUT:
+ RETVAL
+
+If the function's name is B<DESTROY> then the C++ C<delete> function will be
+called and C<THIS> will be given as its parameter. The generated C++ code for
+
+ void
+ color::DESTROY()
+
+will look like this:
+
+ color *THIS = ...; // Initialized as in typemap
+
+ delete THIS;
+
+If the function's name is B<new> then the C++ C<new> function will be called
+to create a dynamic C++ object. The XSUB will expect the class name, which
+will be kept in a variable called C<CLASS>, to be given as the first
+argument.
+
+ color *
+ color::new()
+
+The generated C++ code will call C<new>.
+
+ RETVAL = new color();
+
+The following is an example of a typemap that could be used for this C++
+example.
+
+ TYPEMAP
+ color * O_OBJECT
+
+ OUTPUT
+ # The Perl object is blessed into 'CLASS', which should be a
+ # char* having the name of the package for the blessing.
+ O_OBJECT
+ sv_setref_pv( $arg, CLASS, (void*)$var );
+
+ INPUT
+ O_OBJECT
+ if( sv_isobject($arg) && (SvTYPE(SvRV($arg)) == SVt_PVMG) )
+ $var = ($type)SvIV((SV*)SvRV( $arg ));
+ else{
+ warn( \"${Package}::$func_name() -- $var is not a blessed SV reference\" );
+ XSRETURN_UNDEF;
+ }
+
+=head2 Interface Strategy
+
+When designing an interface between Perl and a C library a straight
+translation from C to XS (such as created by C<h2xs -x>) is often sufficient.
+However, sometimes the interface will look
+very C-like and occasionally nonintuitive, especially when the C function
+modifies one of its parameters, or returns failure inband (as in "negative
+return values mean failure"). In cases where the programmer wishes to
+create a more Perl-like interface the following strategy may help to
+identify the more critical parts of the interface.
+
+Identify the C functions with input/output or output parameters. The XSUBs for
+these functions may be able to return lists to Perl.
+
+Identify the C functions which use some inband info as an indication
+of failure. They may be
+candidates to return undef or an empty list in case of failure. If the
+failure may be detected without a call to the C function, you may want to use
+an INIT: section to report the failure. For failures detectable after the C
+function returns one may want to use a POSTCALL: section to process the
+failure. In more complicated cases use CODE: or PPCODE: sections.
+
+If many functions use the same failure indication based on the return value,
+you may want to create a special typedef to handle this situation. Put
+
+ typedef int negative_is_failure;
+
+near the beginning of XS file, and create an OUTPUT typemap entry
+for C<negative_is_failure> which converts negative values to C<undef>, or
+maybe croak()s. After this the return value of type C<negative_is_failure>
+will create more Perl-like interface.
+
+Identify which values are used by only the C and XSUB functions
+themselves, say, when a parameter to a function should be a contents of a
+global variable. If Perl does not need to access the contents of the value
+then it may not be necessary to provide a translation for that value
+from C to Perl.
+
+Identify the pointers in the C function parameter lists and return
+values. Some pointers may be used to implement input/output or
+output parameters, they can be handled in XS with the C<&> unary operator,
+and, possibly, using the NO_INIT keyword.
+Some others will require handling of types like C<int *>, and one needs
+to decide what a useful Perl translation will do in such a case. When
+the semantic is clear, it is advisable to put the translation into a typemap
+file.
+
+Identify the structures used by the C functions. In many
+cases it may be helpful to use the T_PTROBJ typemap for
+these structures so they can be manipulated by Perl as
+blessed objects. (This is handled automatically by C<h2xs -x>.)
+
+If the same C type is used in several different contexts which require
+different translations, C<typedef> several new types mapped to this C type,
+and create separate F<typemap> entries for these new types. Use these
+types in declarations of return type and parameters to XSUBs.
+
+=head2 Perl Objects And C Structures
+
+When dealing with C structures one should select either
+B<T_PTROBJ> or B<T_PTRREF> for the XS type. Both types are
+designed to handle pointers to complex objects. The
+T_PTRREF type will allow the Perl object to be unblessed
+while the T_PTROBJ type requires that the object be blessed.
+By using T_PTROBJ one can achieve a form of type-checking
+because the XSUB will attempt to verify that the Perl object
+is of the expected type.
+
+The following XS code shows the getnetconfigent() function which is used
+with ONC+ TIRPC. The getnetconfigent() function will return a pointer to a
+C structure and has the C prototype shown below. The example will
+demonstrate how the C pointer will become a Perl reference. Perl will
+consider this reference to be a pointer to a blessed object and will
+attempt to call a destructor for the object. A destructor will be
+provided in the XS source to free the memory used by getnetconfigent().
+Destructors in XS can be created by specifying an XSUB function whose name
+ends with the word B<DESTROY>. XS destructors can be used to free memory
+which may have been malloc'd by another XSUB.
+
+ struct netconfig *getnetconfigent(const char *netid);
+
+A C<typedef> will be created for C<struct netconfig>. The Perl
+object will be blessed in a class matching the name of the C
+type, with the tag C<Ptr> appended, and the name should not
+have embedded spaces if it will be a Perl package name. The
+destructor will be placed in a class corresponding to the
+class of the object and the PREFIX keyword will be used to
+trim the name to the word DESTROY as Perl will expect.
+
+ typedef struct netconfig Netconfig;
+
+ MODULE = RPC PACKAGE = RPC
+
+ Netconfig *
+ getnetconfigent(netid)
+ char *netid
+
+ MODULE = RPC PACKAGE = NetconfigPtr PREFIX = rpcb_
+
+ void
+ rpcb_DESTROY(netconf)
+ Netconfig *netconf
+ CODE:
+ printf("Now in NetconfigPtr::DESTROY\n");
+ free( netconf );
+
+This example requires the following typemap entry. Consult the typemap
+section for more information about adding new typemaps for an extension.
+
+ TYPEMAP
+ Netconfig * T_PTROBJ
+
+This example will be used with the following Perl statements.
+
+ use RPC;
+ $netconf = getnetconfigent("udp");
+
+When Perl destroys the object referenced by $netconf it will send the
+object to the supplied XSUB DESTROY function. Perl cannot determine, and
+does not care, that this object is a C struct and not a Perl object. In
+this sense, there is no difference between the object created by the
+getnetconfigent() XSUB and an object created by a normal Perl subroutine.
+
+=head2 The Typemap
+
+The typemap is a collection of code fragments which are used by the B<xsubpp>
+compiler to map C function parameters and values to Perl values. The
+typemap file may consist of three sections labelled C<TYPEMAP>, C<INPUT>, and
+C<OUTPUT>. An unlabelled initial section is assumed to be a C<TYPEMAP>
+section. The INPUT section tells
+the compiler how to translate Perl values
+into variables of certain C types. The OUTPUT section tells the compiler
+how to translate the values from certain C types into values Perl can
+understand. The TYPEMAP section tells the compiler which of the INPUT and
+OUTPUT code fragments should be used to map a given C type to a Perl value.
+The section labels C<TYPEMAP>, C<INPUT>, or C<OUTPUT> must begin
+in the first column on a line by themselves, and must be in uppercase.
+
+The default typemap in the C<lib/ExtUtils> directory of the Perl source
+contains many useful types which can be used by Perl extensions. Some
+extensions define additional typemaps which they keep in their own directory.
+These additional typemaps may reference INPUT and OUTPUT maps in the main
+typemap. The B<xsubpp> compiler will allow the extension's own typemap to
+override any mappings which are in the default typemap.
+
+Most extensions which require a custom typemap will need only the TYPEMAP
+section of the typemap file. The custom typemap used in the
+getnetconfigent() example shown earlier demonstrates what may be the typical
+use of extension typemaps. That typemap is used to equate a C structure
+with the T_PTROBJ typemap. The typemap used by getnetconfigent() is shown
+here. Note that the C type is separated from the XS type with a tab and
+that the C unary operator C<*> is considered to be a part of the C type name.
+
+ TYPEMAP
+ Netconfig *<tab>T_PTROBJ
+
+Here's a more complicated example: suppose that you wanted C<struct
+netconfig> to be blessed into the class C<Net::Config>. One way to do
+this is to use underscores (_) to separate package names, as follows:
+
+ typedef struct netconfig * Net_Config;
+
+And then provide a typemap entry C<T_PTROBJ_SPECIAL> that maps underscores to
+double-colons (::), and declare C<Net_Config> to be of that type:
+
+
+ TYPEMAP
+ Net_Config T_PTROBJ_SPECIAL
+
+ INPUT
+ T_PTROBJ_SPECIAL
+ if (sv_derived_from($arg, \"${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")) {
+ IV tmp = SvIV((SV*)SvRV($arg));
+ $var = INT2PTR($type, tmp);
+ }
+ else
+ croak(\"$var is not of type ${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\")
+
+ OUTPUT
+ T_PTROBJ_SPECIAL
+ sv_setref_pv($arg, \"${(my $ntt=$ntype)=~s/_/::/g;\$ntt}\",
+ (void*)$var);
+
+The INPUT and OUTPUT sections substitute underscores for double-colons
+on the fly, giving the desired effect. This example demonstrates some
+of the power and versatility of the typemap facility.
+
+The INT2PTR macro (defined in perl.h) casts an integer to a pointer,
+of a given type, taking care of the possible different size of integers
+and pointers. There are also PTR2IV, PTR2UV, PTR2NV macros,
+to map the other way, which may be useful in OUTPUT sections.
+
+=head2 Safely Storing Static Data in XS
+
+Starting with Perl 5.8, a macro framework has been defined to allow
+static data to be safely stored in XS modules that will be accessed from
+a multi-threaded Perl.
+
+Although primarily designed for use with multi-threaded Perl, the macros
+have been designed so that they will work with non-threaded Perl as well.
+
+It is therefore strongly recommended that these macros be used by all
+XS modules that make use of static data.
+
+The easiest way to get a template set of macros to use is by specifying
+the C<-g> (C<--global>) option with h2xs (see L<h2xs>).
+
+Below is an example module that makes use of the macros.
+
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ /* Global Data */
+
+ #define MY_CXT_KEY "BlindMice::_guts" XS_VERSION
+
+ typedef struct {
+ int count;
+ char name[3][100];
+ } my_cxt_t;
+
+ START_MY_CXT
+
+ MODULE = BlindMice PACKAGE = BlindMice
+
+ BOOT:
+ {
+ MY_CXT_INIT;
+ MY_CXT.count = 0;
+ strcpy(MY_CXT.name[0], "None");
+ strcpy(MY_CXT.name[1], "None");
+ strcpy(MY_CXT.name[2], "None");
+ }
+
+ int
+ newMouse(char * name)
+ char * name;
+ PREINIT:
+ dMY_CXT;
+ CODE:
+ if (MY_CXT.count >= 3) {
+ warn("Already have 3 blind mice");
+ RETVAL = 0;
+ }
+ else {
+ RETVAL = ++ MY_CXT.count;
+ strcpy(MY_CXT.name[MY_CXT.count - 1], name);
+ }
+
+ char *
+ get_mouse_name(index)
+ int index
+ CODE:
+ dMY_CXT;
+ RETVAL = MY_CXT.lives ++;
+ if (index > MY_CXT.count)
+ croak("There are only 3 blind mice.");
+ else
+ RETVAL = newSVpv(MY_CXT.name[index - 1]);
+
+ void
+ CLONE(...)
+ CODE:
+ MY_CXT_CLONE;
+
+B<REFERENCE>
+
+=over 5
+
+=item MY_CXT_KEY
+
+This macro is used to define a unique key to refer to the static data
+for an XS module. The suggested naming scheme, as used by h2xs, is to
+use a string that consists of the module name, the string "::_guts"
+and the module version number.
+
+ #define MY_CXT_KEY "MyModule::_guts" XS_VERSION
+
+=item typedef my_cxt_t
+
+This struct typedef I<must> always be called C<my_cxt_t>. The other
+C<CXT*> macros assume the existence of the C<my_cxt_t> typedef name.
+
+Declare a typedef named C<my_cxt_t> that is a structure that contains
+all the data that needs to be interpreter-local.
+
+ typedef struct {
+ int some_value;
+ } my_cxt_t;
+
+=item START_MY_CXT
+
+Always place the START_MY_CXT macro directly after the declaration
+of C<my_cxt_t>.
+
+=item MY_CXT_INIT
+
+The MY_CXT_INIT macro initialises storage for the C<my_cxt_t> struct.
+
+It I<must> be called exactly once, typically in a BOOT: section. If you
+are maintaining multiple interpreters, it should be called once in each
+interpreter instance, except for interpreters cloned from existing ones.
+(But see C<MY_CXT_CLONE> below.)
+
+=item dMY_CXT
+
+Use the dMY_CXT macro (a declaration) in all the functions that access
+MY_CXT.
+
+=item MY_CXT
+
+Use the MY_CXT macro to access members of the C<my_cxt_t> struct. For
+example, if C<my_cxt_t> is
+
+ typedef struct {
+ int index;
+ } my_cxt_t;
+
+then use this to access the C<index> member
+
+ dMY_CXT;
+ MY_CXT.index = 2;
+
+=item aMY_CXT/pMY_CXT
+
+C<dMY_CXT> may be quite expensive to calculate, and to avoid the overhead
+of invoking it in each function it is possible to pass the declaration
+onto other functions using the C<aMY_CXT>/C<pMY_CXT> macros, eg
+
+ void sub1() {
+ dMY_CXT;
+ MY_CXT.index = 1;
+ sub2(aMY_CXT);
+ }
+
+ void sub2(pMY_CXT) {
+ MY_CXT.index = 2;
+ }
+
+Analogously to C<pTHX>, there are equivalent forms for when the macro is the
+first or last in multiple arguments, where an underscore represents a
+comma, i.e. C<_aMY_CXT>, C<aMY_CXT_>, C<_pMY_CXT> and C<pMY_CXT_>.
+
+=item MY_CXT_CLONE
+
+By default, when a new interpreter is created as a copy of an existing one
+(eg via C<< threads->create() >>), both interpreters share the same physical
+my_cxt_t structure. Calling C<MY_CXT_CLONE> (typically via the package's
+C<CLONE()> function), causes a byte-for-byte copy of the structure to be
+taken, and any future dMY_CXT will cause the copy to be accessed instead.
+
+=item MY_CXT_INIT_INTERP(my_perl)
+
+=item dMY_CXT_INTERP(my_perl)
+
+These are versions of the macros which take an explicit interpreter as an
+argument.
+
+=back
+
+Note that these macros will only work together within the I<same> source
+file; that is, a dMY_CTX in one source file will access a different structure
+than a dMY_CTX in another source file.
+
+=head2 Thread-aware system interfaces
+
+Starting from Perl 5.8, in C/C++ level Perl knows how to wrap
+system/library interfaces that have thread-aware versions
+(e.g. getpwent_r()) into frontend macros (e.g. getpwent()) that
+correctly handle the multithreaded interaction with the Perl
+interpreter. This will happen transparently, the only thing
+you need to do is to instantiate a Perl interpreter.
+
+This wrapping happens always when compiling Perl core source
+(PERL_CORE is defined) or the Perl core extensions (PERL_EXT is
+defined). When compiling XS code outside of Perl core the wrapping
+does not take place. Note, however, that intermixing the _r-forms
+(as Perl compiled for multithreaded operation will do) and the _r-less
+forms is neither well-defined (inconsistent results, data corruption,
+or even crashes become more likely), nor is it very portable.
+
+=head1 EXAMPLES
+
+File C<RPC.xs>: Interface to some ONC+ RPC bind library functions.
+
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ #include <rpc/rpc.h>
+
+ typedef struct netconfig Netconfig;
+
+ MODULE = RPC PACKAGE = RPC
+
+ SV *
+ rpcb_gettime(host="localhost")
+ char *host
+ PREINIT:
+ time_t timep;
+ CODE:
+ ST(0) = sv_newmortal();
+ if( rpcb_gettime( host, &timep ) )
+ sv_setnv( ST(0), (double)timep );
+
+ Netconfig *
+ getnetconfigent(netid="udp")
+ char *netid
+
+ MODULE = RPC PACKAGE = NetconfigPtr PREFIX = rpcb_
+
+ void
+ rpcb_DESTROY(netconf)
+ Netconfig *netconf
+ CODE:
+ printf("NetconfigPtr::DESTROY\n");
+ free( netconf );
+
+File C<typemap>: Custom typemap for RPC.xs.
+
+ TYPEMAP
+ Netconfig * T_PTROBJ
+
+File C<RPC.pm>: Perl module for the RPC extension.
+
+ package RPC;
+
+ require Exporter;
+ require DynaLoader;
+ @ISA = qw(Exporter DynaLoader);
+ @EXPORT = qw(rpcb_gettime getnetconfigent);
+
+ bootstrap RPC;
+ 1;
+
+File C<rpctest.pl>: Perl test program for the RPC extension.
+
+ use RPC;
+
+ $netconf = getnetconfigent();
+ $a = rpcb_gettime();
+ print "time = $a\n";
+ print "netconf = $netconf\n";
+
+ $netconf = getnetconfigent("tcp");
+ $a = rpcb_gettime("poplar");
+ print "time = $a\n";
+ print "netconf = $netconf\n";
+
+
+=head1 XS VERSION
+
+This document covers features supported by C<xsubpp> 1.935.
+
+=head1 AUTHOR
+
+Originally written by Dean Roehrich <F<roehrich@cray.com>>.
+
+Maintained since 1996 by The Perl Porters <F<perlbug@perl.org>>.
diff --git a/Master/tlpkg/tlperl/lib/pods/perlxstut.pod b/Master/tlpkg/tlperl/lib/pods/perlxstut.pod
new file mode 100644
index 00000000000..62bef3b0c5f
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/pods/perlxstut.pod
@@ -0,0 +1,1378 @@
+=head1 NAME
+
+perlXStut - Tutorial for writing XSUBs
+
+=head1 DESCRIPTION
+
+This tutorial will educate the reader on the steps involved in creating
+a Perl extension. The reader is assumed to have access to L<perlguts>,
+L<perlapi> and L<perlxs>.
+
+This tutorial starts with very simple examples and becomes more complex,
+with each new example adding new features. Certain concepts may not be
+completely explained until later in the tutorial in order to slowly ease
+the reader into building extensions.
+
+This tutorial was written from a Unix point of view. Where I know them
+to be otherwise different for other platforms (e.g. Win32), I will list
+them. If you find something that was missed, please let me know.
+
+=head1 SPECIAL NOTES
+
+=head2 make
+
+This tutorial assumes that the make program that Perl is configured to
+use is called C<make>. Instead of running "make" in the examples that
+follow, you may have to substitute whatever make program Perl has been
+configured to use. Running B<perl -V:make> should tell you what it is.
+
+=head2 Version caveat
+
+When writing a Perl extension for general consumption, one should expect that
+the extension will be used with versions of Perl different from the
+version available on your machine. Since you are reading this document,
+the version of Perl on your machine is probably 5.005 or later, but the users
+of your extension may have more ancient versions.
+
+To understand what kinds of incompatibilities one may expect, and in the rare
+case that the version of Perl on your machine is older than this document,
+see the section on "Troubleshooting these Examples" for more information.
+
+If your extension uses some features of Perl which are not available on older
+releases of Perl, your users would appreciate an early meaningful warning.
+You would probably put this information into the F<README> file, but nowadays
+installation of extensions may be performed automatically, guided by F<CPAN.pm>
+module or other tools.
+
+In MakeMaker-based installations, F<Makefile.PL> provides the earliest
+opportunity to perform version checks. One can put something like this
+in F<Makefile.PL> for this purpose:
+
+ eval { require 5.007 }
+ or die <<EOD;
+ ############
+ ### This module uses frobnication framework which is not available before
+ ### version 5.007 of Perl. Upgrade your Perl before installing Kara::Mba.
+ ############
+ EOD
+
+=head2 Dynamic Loading versus Static Loading
+
+It is commonly thought that if a system does not have the capability to
+dynamically load a library, you cannot build XSUBs. This is incorrect.
+You I<can> build them, but you must link the XSUBs subroutines with the
+rest of Perl, creating a new executable. This situation is similar to
+Perl 4.
+
+This tutorial can still be used on such a system. The XSUB build mechanism
+will check the system and build a dynamically-loadable library if possible,
+or else a static library and then, optionally, a new statically-linked
+executable with that static library linked in.
+
+Should you wish to build a statically-linked executable on a system which
+can dynamically load libraries, you may, in all the following examples,
+where the command "C<make>" with no arguments is executed, run the command
+"C<make perl>" instead.
+
+If you have generated such a statically-linked executable by choice, then
+instead of saying "C<make test>", you should say "C<make test_static>".
+On systems that cannot build dynamically-loadable libraries at all, simply
+saying "C<make test>" is sufficient.
+
+=head1 TUTORIAL
+
+Now let's go on with the show!
+
+=head2 EXAMPLE 1
+
+Our first extension will be very simple. When we call the routine in the
+extension, it will print out a well-known message and return.
+
+Run "C<h2xs -A -n Mytest>". This creates a directory named Mytest,
+possibly under ext/ if that directory exists in the current working
+directory. Several files will be created under the Mytest dir, including
+MANIFEST, Makefile.PL, lib/Mytest.pm, Mytest.xs, t/Mytest.t, and Changes.
+
+The MANIFEST file contains the names of all the files just created in the
+Mytest directory.
+
+The file Makefile.PL should look something like this:
+
+ use ExtUtils::MakeMaker;
+ # See lib/ExtUtils/MakeMaker.pm for details of how to influence
+ # the contents of the Makefile that is written.
+ WriteMakefile(
+ NAME => 'Mytest',
+ VERSION_FROM => 'Mytest.pm', # finds $VERSION
+ LIBS => [''], # e.g., '-lm'
+ DEFINE => '', # e.g., '-DHAVE_SOMETHING'
+ INC => '', # e.g., '-I/usr/include/other'
+ );
+
+The file Mytest.pm should start with something like this:
+
+ package Mytest;
+
+ use 5.008008;
+ use strict;
+ use warnings;
+
+ require Exporter;
+
+ our @ISA = qw(Exporter);
+ our %EXPORT_TAGS = ( 'all' => [ qw(
+
+ ) ] );
+
+ our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
+
+ our @EXPORT = qw(
+
+ );
+
+ our $VERSION = '0.01';
+
+ require XSLoader;
+ XSLoader::load('Mytest', $VERSION);
+
+ # Preloaded methods go here.
+
+ 1;
+ __END__
+ # Below is the stub of documentation for your module. You better edit it!
+
+The rest of the .pm file contains sample code for providing documentation for
+the extension.
+
+Finally, the Mytest.xs file should look something like this:
+
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ #include "ppport.h"
+
+ MODULE = Mytest PACKAGE = Mytest
+
+Let's edit the .xs file by adding this to the end of the file:
+
+ void
+ hello()
+ CODE:
+ printf("Hello, world!\n");
+
+It is okay for the lines starting at the "CODE:" line to not be indented.
+However, for readability purposes, it is suggested that you indent CODE:
+one level and the lines following one more level.
+
+Now we'll run "C<perl Makefile.PL>". This will create a real Makefile,
+which make needs. Its output looks something like:
+
+ % perl Makefile.PL
+ Checking if your kit is complete...
+ Looks good
+ Writing Makefile for Mytest
+ %
+
+Now, running make will produce output that looks something like this (some
+long lines have been shortened for clarity and some extraneous lines have
+been deleted):
+
+ % make
+ cp lib/Mytest.pm blib/lib/Mytest.pm
+ perl xsubpp -typemap typemap Mytest.xs > Mytest.xsc && mv Mytest.xsc Mytest.c
+ Please specify prototyping behavior for Mytest.xs (see perlxs manual)
+ cc -c Mytest.c
+ Running Mkbootstrap for Mytest ()
+ chmod 644 Mytest.bs
+ rm -f blib/arch/auto/Mytest/Mytest.so
+ cc -shared -L/usr/local/lib Mytest.o -o blib/arch/auto/Mytest/Mytest.so \
+ \
+
+ chmod 755 blib/arch/auto/Mytest/Mytest.so
+ cp Mytest.bs blib/arch/auto/Mytest/Mytest.bs
+ chmod 644 blib/arch/auto/Mytest/Mytest.bs
+ Manifying blib/man3/Mytest.3pm
+ %
+
+You can safely ignore the line about "prototyping behavior" - it is
+explained in L<perlxs/"The PROTOTYPES: Keyword">.
+
+If you are on a Win32 system, and the build process fails with linker
+errors for functions in the C library, check if your Perl is configured
+to use PerlCRT (running B<perl -V:libc> should show you if this is the
+case). If Perl is configured to use PerlCRT, you have to make sure
+PerlCRT.lib is copied to the same location that msvcrt.lib lives in,
+so that the compiler can find it on its own. msvcrt.lib is usually
+found in the Visual C compiler's lib directory (e.g. C:/DevStudio/VC/lib).
+
+Perl has its own special way of easily writing test scripts, but for this
+example only, we'll create our own test script. Create a file called hello
+that looks like this:
+
+ #! /opt/perl5/bin/perl
+
+ use ExtUtils::testlib;
+
+ use Mytest;
+
+ Mytest::hello();
+
+Now we make the script executable (C<chmod +x hello>), run the script
+and we should see the following output:
+
+ % ./hello
+ Hello, world!
+ %
+
+=head2 EXAMPLE 2
+
+Now let's add to our extension a subroutine that will take a single numeric
+argument as input and return 0 if the number is even or 1 if the number
+is odd.
+
+Add the following to the end of Mytest.xs:
+
+ int
+ is_even(input)
+ int input
+ CODE:
+ RETVAL = (input % 2 == 0);
+ OUTPUT:
+ RETVAL
+
+There does not need to be whitespace at the start of the "C<int input>"
+line, but it is useful for improving readability. Placing a semi-colon at
+the end of that line is also optional. Any amount and kind of whitespace
+may be placed between the "C<int>" and "C<input>".
+
+Now re-run make to rebuild our new shared library.
+
+Now perform the same steps as before, generating a Makefile from the
+Makefile.PL file, and running make.
+
+In order to test that our extension works, we now need to look at the
+file Mytest.t. This file is set up to imitate the same kind of testing
+structure that Perl itself has. Within the test script, you perform a
+number of tests to confirm the behavior of the extension, printing "ok"
+when the test is correct, "not ok" when it is not.
+
+ use Test::More tests => 4;
+ BEGIN { use_ok('Mytest') };
+
+ #########################
+
+ # Insert your test code below, the Test::More module is use()ed here so read
+ # its man page ( perldoc Test::More ) for help writing this test script.
+
+ is(&Mytest::is_even(0), 1);
+ is(&Mytest::is_even(1), 0);
+ is(&Mytest::is_even(2), 1);
+
+We will be calling the test script through the command "C<make test>". You
+should see output that looks something like this:
+
+ %make test
+ PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e" "test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
+ t/Mytest....ok
+ All tests successful.
+ Files=1, Tests=4, 0 wallclock secs ( 0.03 cusr + 0.00 csys = 0.03 CPU)
+ %
+
+=head2 What has gone on?
+
+The program h2xs is the starting point for creating extensions. In later
+examples we'll see how we can use h2xs to read header files and generate
+templates to connect to C routines.
+
+h2xs creates a number of files in the extension directory. The file
+Makefile.PL is a perl script which will generate a true Makefile to build
+the extension. We'll take a closer look at it later.
+
+The .pm and .xs files contain the meat of the extension. The .xs file holds
+the C routines that make up the extension. The .pm file contains routines
+that tell Perl how to load your extension.
+
+Generating the Makefile and running C<make> created a directory called blib
+(which stands for "build library") in the current working directory. This
+directory will contain the shared library that we will build. Once we have
+tested it, we can install it into its final location.
+
+Invoking the test script via "C<make test>" did something very important.
+It invoked perl with all those C<-I> arguments so that it could find the
+various files that are part of the extension. It is I<very> important that
+while you are still testing extensions that you use "C<make test>". If you
+try to run the test script all by itself, you will get a fatal error.
+Another reason it is important to use "C<make test>" to run your test
+script is that if you are testing an upgrade to an already-existing version,
+using "C<make test>" ensures that you will test your new extension, not the
+already-existing version.
+
+When Perl sees a C<use extension;>, it searches for a file with the same name
+as the C<use>'d extension that has a .pm suffix. If that file cannot be found,
+Perl dies with a fatal error. The default search path is contained in the
+C<@INC> array.
+
+In our case, Mytest.pm tells perl that it will need the Exporter and Dynamic
+Loader extensions. It then sets the C<@ISA> and C<@EXPORT> arrays and the
+C<$VERSION> scalar; finally it tells perl to bootstrap the module. Perl
+will call its dynamic loader routine (if there is one) and load the shared
+library.
+
+The two arrays C<@ISA> and C<@EXPORT> are very important. The C<@ISA>
+array contains a list of other packages in which to search for methods (or
+subroutines) that do not exist in the current package. This is usually
+only important for object-oriented extensions (which we will talk about
+much later), and so usually doesn't need to be modified.
+
+The C<@EXPORT> array tells Perl which of the extension's variables and
+subroutines should be placed into the calling package's namespace. Because
+you don't know if the user has already used your variable and subroutine
+names, it's vitally important to carefully select what to export. Do I<not>
+export method or variable names I<by default> without a good reason.
+
+As a general rule, if the module is trying to be object-oriented then don't
+export anything. If it's just a collection of functions and variables, then
+you can export them via another array, called C<@EXPORT_OK>. This array
+does not automatically place its subroutine and variable names into the
+namespace unless the user specifically requests that this be done.
+
+See L<perlmod> for more information.
+
+The C<$VERSION> variable is used to ensure that the .pm file and the shared
+library are "in sync" with each other. Any time you make changes to
+the .pm or .xs files, you should increment the value of this variable.
+
+=head2 Writing good test scripts
+
+The importance of writing good test scripts cannot be over-emphasized. You
+should closely follow the "ok/not ok" style that Perl itself uses, so that
+it is very easy and unambiguous to determine the outcome of each test case.
+When you find and fix a bug, make sure you add a test case for it.
+
+By running "C<make test>", you ensure that your Mytest.t script runs and uses
+the correct version of your extension. If you have many test cases,
+save your test files in the "t" directory and use the suffix ".t".
+When you run "C<make test>", all of these test files will be executed.
+
+=head2 EXAMPLE 3
+
+Our third extension will take one argument as its input, round off that
+value, and set the I<argument> to the rounded value.
+
+Add the following to the end of Mytest.xs:
+
+ void
+ round(arg)
+ double arg
+ CODE:
+ if (arg > 0.0) {
+ arg = floor(arg + 0.5);
+ } else if (arg < 0.0) {
+ arg = ceil(arg - 0.5);
+ } else {
+ arg = 0.0;
+ }
+ OUTPUT:
+ arg
+
+Edit the Makefile.PL file so that the corresponding line looks like this:
+
+ 'LIBS' => ['-lm'], # e.g., '-lm'
+
+Generate the Makefile and run make. Change the test number in Mytest.t to
+"9" and add the following tests:
+
+ $i = -1.5; &Mytest::round($i); is( $i, -2.0 );
+ $i = -1.1; &Mytest::round($i); is( $i, -1.0 );
+ $i = 0.0; &Mytest::round($i); is( $i, 0.0 );
+ $i = 0.5; &Mytest::round($i); is( $i, 1.0 );
+ $i = 1.2; &Mytest::round($i); is( $i, 1.0 );
+
+Running "C<make test>" should now print out that all nine tests are okay.
+
+Notice that in these new test cases, the argument passed to round was a
+scalar variable. You might be wondering if you can round a constant or
+literal. To see what happens, temporarily add the following line to Mytest.t:
+
+ &Mytest::round(3);
+
+Run "C<make test>" and notice that Perl dies with a fatal error. Perl won't
+let you change the value of constants!
+
+=head2 What's new here?
+
+=over 4
+
+=item *
+
+We've made some changes to Makefile.PL. In this case, we've specified an
+extra library to be linked into the extension's shared library, the math
+library libm in this case. We'll talk later about how to write XSUBs that
+can call every routine in a library.
+
+=item *
+
+The value of the function is not being passed back as the function's return
+value, but by changing the value of the variable that was passed into the
+function. You might have guessed that when you saw that the return value
+of round is of type "void".
+
+=back
+
+=head2 Input and Output Parameters
+
+You specify the parameters that will be passed into the XSUB on the line(s)
+after you declare the function's return value and name. Each input parameter
+line starts with optional whitespace, and may have an optional terminating
+semicolon.
+
+The list of output parameters occurs at the very end of the function, just
+after the OUTPUT: directive. The use of RETVAL tells Perl that you
+wish to send this value back as the return value of the XSUB function. In
+Example 3, we wanted the "return value" placed in the original variable
+which we passed in, so we listed it (and not RETVAL) in the OUTPUT: section.
+
+=head2 The XSUBPP Program
+
+The B<xsubpp> program takes the XS code in the .xs file and translates it into
+C code, placing it in a file whose suffix is .c. The C code created makes
+heavy use of the C functions within Perl.
+
+=head2 The TYPEMAP file
+
+The B<xsubpp> program uses rules to convert from Perl's data types (scalar,
+array, etc.) to C's data types (int, char, etc.). These rules are stored
+in the typemap file ($PERLLIB/ExtUtils/typemap). This file is split into
+three parts.
+
+The first section maps various C data types to a name, which corresponds
+somewhat with the various Perl types. The second section contains C code
+which B<xsubpp> uses to handle input parameters. The third section contains
+C code which B<xsubpp> uses to handle output parameters.
+
+Let's take a look at a portion of the .c file created for our extension.
+The file name is Mytest.c:
+
+ XS(XS_Mytest_round)
+ {
+ dXSARGS;
+ if (items != 1)
+ Perl_croak(aTHX_ "Usage: Mytest::round(arg)");
+ PERL_UNUSED_VAR(cv); /* -W */
+ {
+ double arg = (double)SvNV(ST(0)); /* XXXXX */
+ if (arg > 0.0) {
+ arg = floor(arg + 0.5);
+ } else if (arg < 0.0) {
+ arg = ceil(arg - 0.5);
+ } else {
+ arg = 0.0;
+ }
+ sv_setnv(ST(0), (double)arg); /* XXXXX */
+ SvSETMAGIC(ST(0));
+ }
+ XSRETURN_EMPTY;
+ }
+
+Notice the two lines commented with "XXXXX". If you check the first section
+of the typemap file, you'll see that doubles are of type T_DOUBLE. In the
+INPUT section, an argument that is T_DOUBLE is assigned to the variable
+arg by calling the routine SvNV on something, then casting it to double,
+then assigned to the variable arg. Similarly, in the OUTPUT section,
+once arg has its final value, it is passed to the sv_setnv function to
+be passed back to the calling subroutine. These two functions are explained
+in L<perlguts>; we'll talk more later about what that "ST(0)" means in the
+section on the argument stack.
+
+=head2 Warning about Output Arguments
+
+In general, it's not a good idea to write extensions that modify their input
+parameters, as in Example 3. Instead, you should probably return multiple
+values in an array and let the caller handle them (we'll do this in a later
+example). However, in order to better accommodate calling pre-existing C
+routines, which often do modify their input parameters, this behavior is
+tolerated.
+
+=head2 EXAMPLE 4
+
+In this example, we'll now begin to write XSUBs that will interact with
+pre-defined C libraries. To begin with, we will build a small library of
+our own, then let h2xs write our .pm and .xs files for us.
+
+Create a new directory called Mytest2 at the same level as the directory
+Mytest. In the Mytest2 directory, create another directory called mylib,
+and cd into that directory.
+
+Here we'll create some files that will generate a test library. These will
+include a C source file and a header file. We'll also create a Makefile.PL
+in this directory. Then we'll make sure that running make at the Mytest2
+level will automatically run this Makefile.PL file and the resulting Makefile.
+
+In the mylib directory, create a file mylib.h that looks like this:
+
+ #define TESTVAL 4
+
+ extern double foo(int, long, const char*);
+
+Also create a file mylib.c that looks like this:
+
+ #include <stdlib.h>
+ #include "./mylib.h"
+
+ double
+ foo(int a, long b, const char *c)
+ {
+ return (a + b + atof(c) + TESTVAL);
+ }
+
+And finally create a file Makefile.PL that looks like this:
+
+ use ExtUtils::MakeMaker;
+ $Verbose = 1;
+ WriteMakefile(
+ NAME => 'Mytest2::mylib',
+ SKIP => [qw(all static static_lib dynamic dynamic_lib)],
+ clean => {'FILES' => 'libmylib$(LIB_EXT)'},
+ );
+
+
+ sub MY::top_targets {
+ '
+ all :: static
+
+ pure_all :: static
+
+ static :: libmylib$(LIB_EXT)
+
+ libmylib$(LIB_EXT): $(O_FILES)
+ $(AR) cr libmylib$(LIB_EXT) $(O_FILES)
+ $(RANLIB) libmylib$(LIB_EXT)
+
+ ';
+ }
+
+Make sure you use a tab and not spaces on the lines beginning with "$(AR)"
+and "$(RANLIB)". Make will not function properly if you use spaces.
+It has also been reported that the "cr" argument to $(AR) is unnecessary
+on Win32 systems.
+
+We will now create the main top-level Mytest2 files. Change to the directory
+above Mytest2 and run the following command:
+
+ % h2xs -O -n Mytest2 ./Mytest2/mylib/mylib.h
+
+This will print out a warning about overwriting Mytest2, but that's okay.
+Our files are stored in Mytest2/mylib, and will be untouched.
+
+The normal Makefile.PL that h2xs generates doesn't know about the mylib
+directory. We need to tell it that there is a subdirectory and that we
+will be generating a library in it. Let's add the argument MYEXTLIB to
+the WriteMakefile call so that it looks like this:
+
+ WriteMakefile(
+ 'NAME' => 'Mytest2',
+ 'VERSION_FROM' => 'Mytest2.pm', # finds $VERSION
+ 'LIBS' => [''], # e.g., '-lm'
+ 'DEFINE' => '', # e.g., '-DHAVE_SOMETHING'
+ 'INC' => '', # e.g., '-I/usr/include/other'
+ 'MYEXTLIB' => 'mylib/libmylib$(LIB_EXT)',
+ );
+
+and then at the end add a subroutine (which will override the pre-existing
+subroutine). Remember to use a tab character to indent the line beginning
+with "cd"!
+
+ sub MY::postamble {
+ '
+ $(MYEXTLIB): mylib/Makefile
+ cd mylib && $(MAKE) $(PASSTHRU)
+ ';
+ }
+
+Let's also fix the MANIFEST file so that it accurately reflects the contents
+of our extension. The single line that says "mylib" should be replaced by
+the following three lines:
+
+ mylib/Makefile.PL
+ mylib/mylib.c
+ mylib/mylib.h
+
+To keep our namespace nice and unpolluted, edit the .pm file and change
+the variable C<@EXPORT> to C<@EXPORT_OK>. Finally, in the
+.xs file, edit the #include line to read:
+
+ #include "mylib/mylib.h"
+
+And also add the following function definition to the end of the .xs file:
+
+ double
+ foo(a,b,c)
+ int a
+ long b
+ const char * c
+ OUTPUT:
+ RETVAL
+
+Now we also need to create a typemap file because the default Perl doesn't
+currently support the const char * type. Create a file called typemap in
+the Mytest2 directory and place the following in it:
+
+ const char * T_PV
+
+Now run perl on the top-level Makefile.PL. Notice that it also created a
+Makefile in the mylib directory. Run make and watch that it does cd into
+the mylib directory and run make in there as well.
+
+Now edit the Mytest2.t script and change the number of tests to "4",
+and add the following lines to the end of the script:
+
+ is( &Mytest2::foo(1, 2, "Hello, world!"), 7 );
+ is( &Mytest2::foo(1, 2, "0.0"), 7 );
+ ok( abs(&Mytest2::foo(0, 0, "-3.4") - 0.6) <= 0.01 );
+
+(When dealing with floating-point comparisons, it is best to not check for
+equality, but rather that the difference between the expected and actual
+result is below a certain amount (called epsilon) which is 0.01 in this case)
+
+Run "C<make test>" and all should be well. There are some warnings on missing tests
+for the Mytest2::mylib extension, but you can ignore them.
+
+=head2 What has happened here?
+
+Unlike previous examples, we've now run h2xs on a real include file. This
+has caused some extra goodies to appear in both the .pm and .xs files.
+
+=over 4
+
+=item *
+
+In the .xs file, there's now a #include directive with the absolute path to
+the mylib.h header file. We changed this to a relative path so that we
+could move the extension directory if we wanted to.
+
+=item *
+
+There's now some new C code that's been added to the .xs file. The purpose
+of the C<constant> routine is to make the values that are #define'd in the
+header file accessible by the Perl script (by calling either C<TESTVAL> or
+C<&Mytest2::TESTVAL>). There's also some XS code to allow calls to the
+C<constant> routine.
+
+=item *
+
+The .pm file originally exported the name C<TESTVAL> in the C<@EXPORT> array.
+This could lead to name clashes. A good rule of thumb is that if the #define
+is only going to be used by the C routines themselves, and not by the user,
+they should be removed from the C<@EXPORT> array. Alternately, if you don't
+mind using the "fully qualified name" of a variable, you could move most
+or all of the items from the C<@EXPORT> array into the C<@EXPORT_OK> array.
+
+=item *
+
+If our include file had contained #include directives, these would not have
+been processed by h2xs. There is no good solution to this right now.
+
+=item *
+
+We've also told Perl about the library that we built in the mylib
+subdirectory. That required only the addition of the C<MYEXTLIB> variable
+to the WriteMakefile call and the replacement of the postamble subroutine
+to cd into the subdirectory and run make. The Makefile.PL for the
+library is a bit more complicated, but not excessively so. Again we
+replaced the postamble subroutine to insert our own code. This code
+simply specified that the library to be created here was a static archive
+library (as opposed to a dynamically loadable library) and provided the
+commands to build it.
+
+=back
+
+=head2 Anatomy of .xs file
+
+The .xs file of L<"EXAMPLE 4"> contained some new elements. To understand
+the meaning of these elements, pay attention to the line which reads
+
+ MODULE = Mytest2 PACKAGE = Mytest2
+
+Anything before this line is plain C code which describes which headers
+to include, and defines some convenience functions. No translations are
+performed on this part, apart from having embedded POD documentation
+skipped over (see L<perlpod>) it goes into the generated output C file as is.
+
+Anything after this line is the description of XSUB functions.
+These descriptions are translated by B<xsubpp> into C code which
+implements these functions using Perl calling conventions, and which
+makes these functions visible from Perl interpreter.
+
+Pay a special attention to the function C<constant>. This name appears
+twice in the generated .xs file: once in the first part, as a static C
+function, then another time in the second part, when an XSUB interface to
+this static C function is defined.
+
+This is quite typical for .xs files: usually the .xs file provides
+an interface to an existing C function. Then this C function is defined
+somewhere (either in an external library, or in the first part of .xs file),
+and a Perl interface to this function (i.e. "Perl glue") is described in the
+second part of .xs file. The situation in L<"EXAMPLE 1">, L<"EXAMPLE 2">,
+and L<"EXAMPLE 3">, when all the work is done inside the "Perl glue", is
+somewhat of an exception rather than the rule.
+
+=head2 Getting the fat out of XSUBs
+
+In L<"EXAMPLE 4"> the second part of .xs file contained the following
+description of an XSUB:
+
+ double
+ foo(a,b,c)
+ int a
+ long b
+ const char * c
+ OUTPUT:
+ RETVAL
+
+Note that in contrast with L<"EXAMPLE 1">, L<"EXAMPLE 2"> and L<"EXAMPLE 3">,
+this description does not contain the actual I<code> for what is done
+is done during a call to Perl function foo(). To understand what is going
+on here, one can add a CODE section to this XSUB:
+
+ double
+ foo(a,b,c)
+ int a
+ long b
+ const char * c
+ CODE:
+ RETVAL = foo(a,b,c);
+ OUTPUT:
+ RETVAL
+
+However, these two XSUBs provide almost identical generated C code: B<xsubpp>
+compiler is smart enough to figure out the C<CODE:> section from the first
+two lines of the description of XSUB. What about C<OUTPUT:> section? In
+fact, that is absolutely the same! The C<OUTPUT:> section can be removed
+as well, I<as far as C<CODE:> section or C<PPCODE:> section> is not
+specified: B<xsubpp> can see that it needs to generate a function call
+section, and will autogenerate the OUTPUT section too. Thus one can
+shortcut the XSUB to become:
+
+ double
+ foo(a,b,c)
+ int a
+ long b
+ const char * c
+
+Can we do the same with an XSUB
+
+ int
+ is_even(input)
+ int input
+ CODE:
+ RETVAL = (input % 2 == 0);
+ OUTPUT:
+ RETVAL
+
+of L<"EXAMPLE 2">? To do this, one needs to define a C function C<int
+is_even(int input)>. As we saw in L<Anatomy of .xs file>, a proper place
+for this definition is in the first part of .xs file. In fact a C function
+
+ int
+ is_even(int arg)
+ {
+ return (arg % 2 == 0);
+ }
+
+is probably overkill for this. Something as simple as a C<#define> will
+do too:
+
+ #define is_even(arg) ((arg) % 2 == 0)
+
+After having this in the first part of .xs file, the "Perl glue" part becomes
+as simple as
+
+ int
+ is_even(input)
+ int input
+
+This technique of separation of the glue part from the workhorse part has
+obvious tradeoffs: if you want to change a Perl interface, you need to
+change two places in your code. However, it removes a lot of clutter,
+and makes the workhorse part independent from idiosyncrasies of Perl calling
+convention. (In fact, there is nothing Perl-specific in the above description,
+a different version of B<xsubpp> might have translated this to TCL glue or
+Python glue as well.)
+
+=head2 More about XSUB arguments
+
+With the completion of Example 4, we now have an easy way to simulate some
+real-life libraries whose interfaces may not be the cleanest in the world.
+We shall now continue with a discussion of the arguments passed to the
+B<xsubpp> compiler.
+
+When you specify arguments to routines in the .xs file, you are really
+passing three pieces of information for each argument listed. The first
+piece is the order of that argument relative to the others (first, second,
+etc). The second is the type of argument, and consists of the type
+declaration of the argument (e.g., int, char*, etc). The third piece is
+the calling convention for the argument in the call to the library function.
+
+While Perl passes arguments to functions by reference,
+C passes arguments by value; to implement a C function which modifies data
+of one of the "arguments", the actual argument of this C function would be
+a pointer to the data. Thus two C functions with declarations
+
+ int string_length(char *s);
+ int upper_case_char(char *cp);
+
+may have completely different semantics: the first one may inspect an array
+of chars pointed by s, and the second one may immediately dereference C<cp>
+and manipulate C<*cp> only (using the return value as, say, a success
+indicator). From Perl one would use these functions in
+a completely different manner.
+
+One conveys this info to B<xsubpp> by replacing C<*> before the
+argument by C<&>. C<&> means that the argument should be passed to a library
+function by its address. The above two function may be XSUB-ified as
+
+ int
+ string_length(s)
+ char * s
+
+ int
+ upper_case_char(cp)
+ char &cp
+
+For example, consider:
+
+ int
+ foo(a,b)
+ char &a
+ char * b
+
+The first Perl argument to this function would be treated as a char and assigned
+to the variable a, and its address would be passed into the function foo.
+The second Perl argument would be treated as a string pointer and assigned to the
+variable b. The I<value> of b would be passed into the function foo. The
+actual call to the function foo that B<xsubpp> generates would look like this:
+
+ foo(&a, b);
+
+B<xsubpp> will parse the following function argument lists identically:
+
+ char &a
+ char&a
+ char & a
+
+However, to help ease understanding, it is suggested that you place a "&"
+next to the variable name and away from the variable type), and place a
+"*" near the variable type, but away from the variable name (as in the
+call to foo above). By doing so, it is easy to understand exactly what
+will be passed to the C function; it will be whatever is in the "last
+column".
+
+You should take great pains to try to pass the function the type of variable
+it wants, when possible. It will save you a lot of trouble in the long run.
+
+=head2 The Argument Stack
+
+If we look at any of the C code generated by any of the examples except
+example 1, you will notice a number of references to ST(n), where n is
+usually 0. "ST" is actually a macro that points to the n'th argument
+on the argument stack. ST(0) is thus the first argument on the stack and
+therefore the first argument passed to the XSUB, ST(1) is the second
+argument, and so on.
+
+When you list the arguments to the XSUB in the .xs file, that tells B<xsubpp>
+which argument corresponds to which of the argument stack (i.e., the first
+one listed is the first argument, and so on). You invite disaster if you
+do not list them in the same order as the function expects them.
+
+The actual values on the argument stack are pointers to the values passed
+in. When an argument is listed as being an OUTPUT value, its corresponding
+value on the stack (i.e., ST(0) if it was the first argument) is changed.
+You can verify this by looking at the C code generated for Example 3.
+The code for the round() XSUB routine contains lines that look like this:
+
+ double arg = (double)SvNV(ST(0));
+ /* Round the contents of the variable arg */
+ sv_setnv(ST(0), (double)arg);
+
+The arg variable is initially set by taking the value from ST(0), then is
+stored back into ST(0) at the end of the routine.
+
+XSUBs are also allowed to return lists, not just scalars. This must be
+done by manipulating stack values ST(0), ST(1), etc, in a subtly
+different way. See L<perlxs> for details.
+
+XSUBs are also allowed to avoid automatic conversion of Perl function arguments
+to C function arguments. See L<perlxs> for details. Some people prefer
+manual conversion by inspecting C<ST(i)> even in the cases when automatic
+conversion will do, arguing that this makes the logic of an XSUB call clearer.
+Compare with L<"Getting the fat out of XSUBs"> for a similar tradeoff of
+a complete separation of "Perl glue" and "workhorse" parts of an XSUB.
+
+While experts may argue about these idioms, a novice to Perl guts may
+prefer a way which is as little Perl-guts-specific as possible, meaning
+automatic conversion and automatic call generation, as in
+L<"Getting the fat out of XSUBs">. This approach has the additional
+benefit of protecting the XSUB writer from future changes to the Perl API.
+
+=head2 Extending your Extension
+
+Sometimes you might want to provide some extra methods or subroutines
+to assist in making the interface between Perl and your extension simpler
+or easier to understand. These routines should live in the .pm file.
+Whether they are automatically loaded when the extension itself is loaded
+or only loaded when called depends on where in the .pm file the subroutine
+definition is placed. You can also consult L<AutoLoader> for an alternate
+way to store and load your extra subroutines.
+
+=head2 Documenting your Extension
+
+There is absolutely no excuse for not documenting your extension.
+Documentation belongs in the .pm file. This file will be fed to pod2man,
+and the embedded documentation will be converted to the manpage format,
+then placed in the blib directory. It will be copied to Perl's
+manpage directory when the extension is installed.
+
+You may intersperse documentation and Perl code within the .pm file.
+In fact, if you want to use method autoloading, you must do this,
+as the comment inside the .pm file explains.
+
+See L<perlpod> for more information about the pod format.
+
+=head2 Installing your Extension
+
+Once your extension is complete and passes all its tests, installing it
+is quite simple: you simply run "make install". You will either need
+to have write permission into the directories where Perl is installed,
+or ask your system administrator to run the make for you.
+
+Alternately, you can specify the exact directory to place the extension's
+files by placing a "PREFIX=/destination/directory" after the make install.
+(or in between the make and install if you have a brain-dead version of make).
+This can be very useful if you are building an extension that will eventually
+be distributed to multiple systems. You can then just archive the files in
+the destination directory and distribute them to your destination systems.
+
+=head2 EXAMPLE 5
+
+In this example, we'll do some more work with the argument stack. The
+previous examples have all returned only a single value. We'll now
+create an extension that returns an array.
+
+This extension is very Unix-oriented (struct statfs and the statfs system
+call). If you are not running on a Unix system, you can substitute for
+statfs any other function that returns multiple values, you can hard-code
+values to be returned to the caller (although this will be a bit harder
+to test the error case), or you can simply not do this example. If you
+change the XSUB, be sure to fix the test cases to match the changes.
+
+Return to the Mytest directory and add the following code to the end of
+Mytest.xs:
+
+ void
+ statfs(path)
+ char * path
+ INIT:
+ int i;
+ struct statfs buf;
+
+ PPCODE:
+ i = statfs(path, &buf);
+ if (i == 0) {
+ XPUSHs(sv_2mortal(newSVnv(buf.f_bavail)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_bfree)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_blocks)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_bsize)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_ffree)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_files)));
+ XPUSHs(sv_2mortal(newSVnv(buf.f_type)));
+ } else {
+ XPUSHs(sv_2mortal(newSVnv(errno)));
+ }
+
+You'll also need to add the following code to the top of the .xs file, just
+after the include of "XSUB.h":
+
+ #include <sys/vfs.h>
+
+Also add the following code segment to Mytest.t while incrementing the "9"
+tests to "11":
+
+ @a = &Mytest::statfs("/blech");
+ ok( scalar(@a) == 1 && $a[0] == 2 );
+ @a = &Mytest::statfs("/");
+ is( scalar(@a), 7 );
+
+=head2 New Things in this Example
+
+This example added quite a few new concepts. We'll take them one at a time.
+
+=over 4
+
+=item *
+
+The INIT: directive contains code that will be placed immediately after
+the argument stack is decoded. C does not allow variable declarations at
+arbitrary locations inside a function,
+so this is usually the best way to declare local variables needed by the XSUB.
+(Alternatively, one could put the whole C<PPCODE:> section into braces, and
+put these declarations on top.)
+
+=item *
+
+This routine also returns a different number of arguments depending on the
+success or failure of the call to statfs. If there is an error, the error
+number is returned as a single-element array. If the call is successful,
+then a 9-element array is returned. Since only one argument is passed into
+this function, we need room on the stack to hold the 9 values which may be
+returned.
+
+We do this by using the PPCODE: directive, rather than the CODE: directive.
+This tells B<xsubpp> that we will be managing the return values that will be
+put on the argument stack by ourselves.
+
+=item *
+
+When we want to place values to be returned to the caller onto the stack,
+we use the series of macros that begin with "XPUSH". There are five
+different versions, for placing integers, unsigned integers, doubles,
+strings, and Perl scalars on the stack. In our example, we placed a
+Perl scalar onto the stack. (In fact this is the only macro which
+can be used to return multiple values.)
+
+The XPUSH* macros will automatically extend the return stack to prevent
+it from being overrun. You push values onto the stack in the order you
+want them seen by the calling program.
+
+=item *
+
+The values pushed onto the return stack of the XSUB are actually mortal SV's.
+They are made mortal so that once the values are copied by the calling
+program, the SV's that held the returned values can be deallocated.
+If they were not mortal, then they would continue to exist after the XSUB
+routine returned, but would not be accessible. This is a memory leak.
+
+=item *
+
+If we were interested in performance, not in code compactness, in the success
+branch we would not use C<XPUSHs> macros, but C<PUSHs> macros, and would
+pre-extend the stack before pushing the return values:
+
+ EXTEND(SP, 7);
+
+The tradeoff is that one needs to calculate the number of return values
+in advance (though overextending the stack will not typically hurt
+anything but memory consumption).
+
+Similarly, in the failure branch we could use C<PUSHs> I<without> extending
+the stack: the Perl function reference comes to an XSUB on the stack, thus
+the stack is I<always> large enough to take one return value.
+
+=back
+
+=head2 EXAMPLE 6
+
+In this example, we will accept a reference to an array as an input
+parameter, and return a reference to an array of hashes. This will
+demonstrate manipulation of complex Perl data types from an XSUB.
+
+This extension is somewhat contrived. It is based on the code in
+the previous example. It calls the statfs function multiple times,
+accepting a reference to an array of filenames as input, and returning
+a reference to an array of hashes containing the data for each of the
+filesystems.
+
+Return to the Mytest directory and add the following code to the end of
+Mytest.xs:
+
+ SV *
+ multi_statfs(paths)
+ SV * paths
+ INIT:
+ AV * results;
+ I32 numpaths = 0;
+ int i, n;
+ struct statfs buf;
+
+ if ((!SvROK(paths))
+ || (SvTYPE(SvRV(paths)) != SVt_PVAV)
+ || ((numpaths = av_len((AV *)SvRV(paths))) < 0))
+ {
+ XSRETURN_UNDEF;
+ }
+ results = (AV *)sv_2mortal((SV *)newAV());
+ CODE:
+ for (n = 0; n <= numpaths; n++) {
+ HV * rh;
+ STRLEN l;
+ char * fn = SvPV(*av_fetch((AV *)SvRV(paths), n, 0), l);
+
+ i = statfs(fn, &buf);
+ if (i != 0) {
+ av_push(results, newSVnv(errno));
+ continue;
+ }
+
+ rh = (HV *)sv_2mortal((SV *)newHV());
+
+ hv_store(rh, "f_bavail", 8, newSVnv(buf.f_bavail), 0);
+ hv_store(rh, "f_bfree", 7, newSVnv(buf.f_bfree), 0);
+ hv_store(rh, "f_blocks", 8, newSVnv(buf.f_blocks), 0);
+ hv_store(rh, "f_bsize", 7, newSVnv(buf.f_bsize), 0);
+ hv_store(rh, "f_ffree", 7, newSVnv(buf.f_ffree), 0);
+ hv_store(rh, "f_files", 7, newSVnv(buf.f_files), 0);
+ hv_store(rh, "f_type", 6, newSVnv(buf.f_type), 0);
+
+ av_push(results, newRV((SV *)rh));
+ }
+ RETVAL = newRV((SV *)results);
+ OUTPUT:
+ RETVAL
+
+And add the following code to Mytest.t, while incrementing the "11"
+tests to "13":
+
+ $results = Mytest::multi_statfs([ '/', '/blech' ]);
+ ok( ref $results->[0]) );
+ ok( ! ref $results->[1] );
+
+=head2 New Things in this Example
+
+There are a number of new concepts introduced here, described below:
+
+=over 4
+
+=item *
+
+This function does not use a typemap. Instead, we declare it as accepting
+one SV* (scalar) parameter, and returning an SV* value, and we take care of
+populating these scalars within the code. Because we are only returning
+one value, we don't need a C<PPCODE:> directive - instead, we use C<CODE:>
+and C<OUTPUT:> directives.
+
+=item *
+
+When dealing with references, it is important to handle them with caution.
+The C<INIT:> block first checks that
+C<SvROK> returns true, which indicates that paths is a valid reference. It
+then verifies that the object referenced by paths is an array, using C<SvRV>
+to dereference paths, and C<SvTYPE> to discover its type. As an added test,
+it checks that the array referenced by paths is non-empty, using the C<av_len>
+function (which returns -1 if the array is empty). The XSRETURN_UNDEF macro
+is used to abort the XSUB and return the undefined value whenever all three of
+these conditions are not met.
+
+=item *
+
+We manipulate several arrays in this XSUB. Note that an array is represented
+internally by an AV* pointer. The functions and macros for manipulating
+arrays are similar to the functions in Perl: C<av_len> returns the highest
+index in an AV*, much like $#array; C<av_fetch> fetches a single scalar value
+from an array, given its index; C<av_push> pushes a scalar value onto the
+end of the array, automatically extending the array as necessary.
+
+Specifically, we read pathnames one at a time from the input array, and
+store the results in an output array (results) in the same order. If
+statfs fails, the element pushed onto the return array is the value of
+errno after the failure. If statfs succeeds, though, the value pushed
+onto the return array is a reference to a hash containing some of the
+information in the statfs structure.
+
+As with the return stack, it would be possible (and a small performance win)
+to pre-extend the return array before pushing data into it, since we know
+how many elements we will return:
+
+ av_extend(results, numpaths);
+
+=item *
+
+We are performing only one hash operation in this function, which is storing
+a new scalar under a key using C<hv_store>. A hash is represented by an HV*
+pointer. Like arrays, the functions for manipulating hashes from an XSUB
+mirror the functionality available from Perl. See L<perlguts> and L<perlapi>
+for details.
+
+=item *
+
+To create a reference, we use the C<newRV> function. Note that you can
+cast an AV* or an HV* to type SV* in this case (and many others). This
+allows you to take references to arrays, hashes and scalars with the same
+function. Conversely, the C<SvRV> function always returns an SV*, which may
+need to be cast to the appropriate type if it is something other than a
+scalar (check with C<SvTYPE>).
+
+=item *
+
+At this point, xsubpp is doing very little work - the differences between
+Mytest.xs and Mytest.c are minimal.
+
+=back
+
+=head2 EXAMPLE 7 (Coming Soon)
+
+XPUSH args AND set RETVAL AND assign return value to array
+
+=head2 EXAMPLE 8 (Coming Soon)
+
+Setting $!
+
+=head2 EXAMPLE 9 Passing open files to XSes
+
+You would think passing files to an XS is difficult, with all the
+typeglobs and stuff. Well, it isn't.
+
+Suppose that for some strange reason we need a wrapper around the
+standard C library function C<fputs()>. This is all we need:
+
+ #define PERLIO_NOT_STDIO 0
+ #include "EXTERN.h"
+ #include "perl.h"
+ #include "XSUB.h"
+
+ #include <stdio.h>
+
+ int
+ fputs(s, stream)
+ char * s
+ FILE * stream
+
+The real work is done in the standard typemap.
+
+B<But> you loose all the fine stuff done by the perlio layers. This
+calls the stdio function C<fputs()>, which knows nothing about them.
+
+The standard typemap offers three variants of PerlIO *:
+C<InputStream> (T_IN), C<InOutStream> (T_INOUT) and C<OutputStream>
+(T_OUT). A bare C<PerlIO *> is considered a T_INOUT. If it matters
+in your code (see below for why it might) #define or typedef
+one of the specific names and use that as the argument or result
+type in your XS file.
+
+The standard typemap does not contain PerlIO * before perl 5.7,
+but it has the three stream variants. Using a PerlIO * directly
+is not backwards compatible unless you provide your own typemap.
+
+For streams coming I<from> perl the main difference is that
+C<OutputStream> will get the output PerlIO * - which may make
+a difference on a socket. Like in our example...
+
+For streams being handed I<to> perl a new file handle is created
+(i.e. a reference to a new glob) and associated with the PerlIO *
+provided. If the read/write state of the PerlIO * is not correct then you
+may get errors or warnings from when the file handle is used.
+So if you opened the PerlIO * as "w" it should really be an
+C<OutputStream> if open as "r" it should be an C<InputStream>.
+
+Now, suppose you want to use perlio layers in your XS. We'll use the
+perlio C<PerlIO_puts()> function as an example.
+
+In the C part of the XS file (above the first MODULE line) you
+have
+
+ #define OutputStream PerlIO *
+ or
+ typedef PerlIO * OutputStream;
+
+
+And this is the XS code:
+
+ int
+ perlioputs(s, stream)
+ char * s
+ OutputStream stream
+ CODE:
+ RETVAL = PerlIO_puts(stream, s);
+ OUTPUT:
+ RETVAL
+
+We have to use a C<CODE> section because C<PerlIO_puts()> has the arguments
+reversed compared to C<fputs()>, and we want to keep the arguments the same.
+
+Wanting to explore this thoroughly, we want to use the stdio C<fputs()>
+on a PerlIO *. This means we have to ask the perlio system for a stdio
+C<FILE *>:
+
+ int
+ perliofputs(s, stream)
+ char * s
+ OutputStream stream
+ PREINIT:
+ FILE *fp = PerlIO_findFILE(stream);
+ CODE:
+ if (fp != (FILE*) 0) {
+ RETVAL = fputs(s, fp);
+ } else {
+ RETVAL = -1;
+ }
+ OUTPUT:
+ RETVAL
+
+Note: C<PerlIO_findFILE()> will search the layers for a stdio
+layer. If it can't find one, it will call C<PerlIO_exportFILE()> to
+generate a new stdio C<FILE>. Please only call C<PerlIO_exportFILE()> if
+you want a I<new> C<FILE>. It will generate one on each call and push a
+new stdio layer. So don't call it repeatedly on the same
+file. C<PerlIO()>_findFILE will retrieve the stdio layer once it has been
+generated by C<PerlIO_exportFILE()>.
+
+This applies to the perlio system only. For versions before 5.7,
+C<PerlIO_exportFILE()> is equivalent to C<PerlIO_findFILE()>.
+
+=head2 Troubleshooting these Examples
+
+As mentioned at the top of this document, if you are having problems with
+these example extensions, you might see if any of these help you.
+
+=over 4
+
+=item *
+
+In versions of 5.002 prior to the gamma version, the test script in Example
+1 will not function properly. You need to change the "use lib" line to
+read:
+
+ use lib './blib';
+
+=item *
+
+In versions of 5.002 prior to version 5.002b1h, the test.pl file was not
+automatically created by h2xs. This means that you cannot say "make test"
+to run the test script. You will need to add the following line before the
+"use extension" statement:
+
+ use lib './blib';
+
+=item *
+
+In versions 5.000 and 5.001, instead of using the above line, you will need
+to use the following line:
+
+ BEGIN { unshift(@INC, "./blib") }
+
+=item *
+
+This document assumes that the executable named "perl" is Perl version 5.
+Some systems may have installed Perl version 5 as "perl5".
+
+=back
+
+=head1 See also
+
+For more information, consult L<perlguts>, L<perlapi>, L<perlxs>, L<perlmod>,
+and L<perlpod>.
+
+=head1 Author
+
+Jeff Okamoto <F<okamoto@corp.hp.com>>
+
+Reviewed and assisted by Dean Roehrich, Ilya Zakharevich, Andreas Koenig,
+and Tim Bunce.
+
+PerlIO material contributed by Lupe Christoph, with some clarification
+by Nick Ing-Simmons.
+
+Changes for h2xs as of Perl 5.8.x by Renee Baecker
+
+=head2 Last Changed
+
+2007/10/11