summaryrefslogtreecommitdiff
path: root/Build/source/doc/texlive.info
blob: 46dea62a7c55f7ee68655ddfa9b34eb6aa0bf08a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
This is texlive.info, produced by makeinfo version 5.2 from
texlive.texi.

This file documents the TeX Live system, etc.

   Copyright (C) 2013 Xxx & Yyy.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the TeX Users Group.
INFO-DIR-SECTION TeX
START-INFO-DIR-ENTRY
* TeX Live: (texlive).                        The TeX Live System.
END-INFO-DIR-ENTRY


File: texlive.info,  Node: Top,  Next: Introduction,  Up: (dir)

The TeX Live System
*******************

This manual documents how to build, install, and use TeX Live.  It
corresponds to version 2014, released in September 2013.

* Menu:

* Introduction::                Overview.

* Build System::                The TeX Live Build System.

* Index::                       General index.


File: texlive.info,  Node: Introduction,  Next: Build System,  Prev: Top,  Up: Top

1 Introduction
**************

This manual corresponds to version 2014 of the TeX Live system, released
in September 2013.


File: texlive.info,  Node: Build System,  Next: Index,  Prev: Introduction,  Up: Top

2 The TeX Live Build System
***************************

The TeX Live build system has been redesigned in 2009, using Autoconf,
Automake, and Libtool.  Thus
   'configure && make && make check && make install'
or the more or less equivalent top-level 'Build' script suffice to build
and install the TeX Live programs, where 'make check' performs various
test of the generated programs that are not necessary but strongly
recommend.

   The main components of the TeX Live build system are TeX specific
programs in subdirectories 'texk/PROG', utility programs in
subdirectories 'utils/PROG', TeX specific libraries in the
subdirectories 'texk/kpathsea' and 'texk/ptexenc' used by the TeX
specific programs, and generic libraries in subdirectories 'libs/LIB'.

   The primary design goal is modularity.  Each program and library
module (or package) specifies its own requirements and properties, such
as required libraries, whether an installed (system) version of a
library can be used, configure options to be seen at the top-level, and
more.  An explicit list of all available modules is only kept in one
central place.

   A second, related goal is to configure and build each library before
configuring any other (program or library) module using that library.
This allows to check for properties and features of a library built as
part of the TeX Live tree in much the same way as for a system version
of that library.

   Most generic libraries and several programs are maintained
independently.  The corresponding modules use (parts of) the distributed
source tree and document any modifications of that source tree.

   All this should simplify upgrading of modules maintained
independently and/or integrating new modules into the TeX Live build
system.

* Menu:

* Prerequisites::               Requirements to Build TeX Live.
* Building and Installing::     Building and Installing TeX Live.
* Source Tree::                 The TeX Live Source Tree.
* Configure Options::           List of all Configure Options.
* Cross Compilation::           Cross Compilation.
* Coding Rules::                Coding Rules for TeX Live.


File: texlive.info,  Node: Prerequisites,  Next: Building and Installing,  Up: Build System

2.1 Requirements to Build TeX Live
==================================

Building the TeX Live programs requires

   * C and C++ compilers

   * GNU 'make'

and uses the libraries included in the TeX Live source tree.  There are,
however, some additional requirements

   * 'xindy' requires GNU 'clisp' and in addition 'perl', 'latex', and
     'pdflatex' to build the rules and/or documentation.

   * Autodetection of the TeX Live platform name for 'biber' requires
     'perl'.

   * 'xpdfopen' and 'xdvik' require X11 headers and libraries (often a
     "development" package, not installed by default).

   * XeTeX requires an Objective C++ compiler under Mac OS X or
     otherwise 'libfontconfig' (again both headers and library).

   * Modification of any '.y' or '.l' source files requires 'bison' or
     'flex' to updatete the corresponding C sources.

   * Modification of any part of the build system ('M4' macros,
     'configure.ac', 'Makefile.am', or their fragments) requires GNU M4,
     GNU Autoconf, GNU Automake, and GNU Libtool to update the generated
     files.

Without the required tools modifying such files or building these
programs must avoided, e.g., via '--disable-xindy' or '--without-x'.


File: texlive.info,  Node: Building and Installing,  Next: Source Tree,  Prev: Prerequisites,  Up: Build System

2.2 Building and Installing TeX Live
====================================

The top-level 'Build' script can be used to configure and build
everything in a subdirectory (root of the build tree, default 'Work'),
install everything in an other subdirectory (default 'inst'), and
finally run 'make check'.  Several details of this process can be
specified via environment variables and a few leading options; all
remaining arguments (assignments or options) are passed to the
'configure' script.  Or one can run 'configure' and 'make' in a suitable
empty subdirectory.

   Running the top-level 'configure' script configures just the
top-level and the subdirectories 'libs', 'utils', and 'texk'.  Running
'make' at the top-level iterates over all TeX specific libraries, first
configuring the module if necessary to create the 'Makefile' and then
building it if that is required.  Finally 'make' is run in 'libs',
'utils', and 'texk' to iterate over all generic libraries, utility
programs, and TeX specific programs.  Running the top-level 'make' a
second time iterates again over all library and program modules but will
find nothing to be done.

   In case configuring or building a module fails, one could fix the
problem, remove the subdirectory for the module from the build tree, and
rerun the top-level 'make' (or 'Build' script with '--no-clean' as
additional first argument).

   With the configure option '--disable-all-pkgs' all program and
library modules are configured but none of them are built.  The
'Makefile' for each such module contains all build rules and
dependencies and can be invoked to build an individual program or
library and causes to first build any required libraries.  This build
"on demand" procedure is used, e.g., in the 'luatex' repository to build
LuaTeX, essentially from a subset of the complete TeX Live tree.

2.2.1 Installation Paths
------------------------

Running 'make install' (or 'make install-strip') installs executables in
'BINDIR', libraries in 'LIBDIR', headers in 'INCLUDEDIR', data
(including "linked scripts") in 'DATAROOTDIR/texmf-dist', manpages in
'MANDIR', and TeX info files in 'INFODIR'.  The values of these
directories are determined by 'configure' and can be specified explictly
as options such as '--prefix=PREFIX' or '--bindir=BINDIR'; otherwise
they are given by their usual Autoconf defaults

     PREFIX                  /usr/local
     EXEC_PREFIX             PREFIX
     BINDIR                  EXEC_PREFIX/bin
     LIBDIR                  EXEC_PREFIX/lib
     INCLUDEDIR              PREFIX/include
     DATAROOTDIR             PREFIX/share
     MANDIR                  DATAROOTDIR/man
     INFODIR                 DATAROOTDIR/info

and modified as follows:

   * If the option '--enable-multiplatform' is given (or implied for a
     native TeX Live build), '/HOST', i.e., the canonical host name is
     appended to 'BINDIR' and 'LIBDIR'.

   * In a native TeX Live build 'DATAROOTDIR' is set to 'PREFIX',
     'MANDIR' to 'PREFIX/texmf-dist/doc/man', and 'INFODIR' to
     'PREFIX/texmf-dist/doc/info'.

The top-level 'configure' script displays all these installation paths.

   For a native TeX Live build either for the TeX Live DVD or for an
additional platform the contents of 'BINDIR' should be copied to the
directory 'Master/bin/ARCH' of the TeX Live tree where 'ARCH' is the TeX
Live platform name corresponding to canonical host name 'HOST', the
contents of 'LIBDIR' and 'INCLUDEDIR' can be discarded, and everything
else should match files already present in the TeX Live tree.

2.2.2 Linked Scripts
--------------------

Quite a few executables are architecture independent Shell, Perl, or
other scripts.  Some of them are maintained as part of the TeX Live
source tree, but most are maintained elsewhere with copies under
'texk/texlive/linked_scripts'.  They are installed under
'DATAROOTDIR/texmf-dist/scripts'; for Unix-like systems there is a
symbolic link pointing, e.g., from 'BINDIR/ps2eps' to
'DATAROOTDIR/texmf-dist/scripts/ps2eps/ps2eps.pl' whereas for Windows
'BINDIR/ps2eps.exe' is a copy of a small standard binary serving the
same purpose.  One reason for all this is to avoid having many copies
for the same script, but most importantly this allows to invoke the same
Perl or other script under Windows.

2.2.3 Distro Builds
-------------------

For a distro build you must use
   '--disable-native-texlive-build'
and should use
   '--with-banner-add=/SOMEDISTRO'
to identify your distro.  You may specify
   '--enable-shared'
to build shared TeX specific libraries and might add
   '--disable-static'
to not build the static ones.  You would like to use
   '--with-system-LIB' for as many libraries as possible and may then
have to add '--with-LIB-includes=DIR' and/or '--with-LIB-libdir=DIR'.

   You should specify
    '--prefix=/usr' or perhaps '--prefix=/opt/TeXLive'
and may have to add
   '--libdir=\${exec_prefix}/lib64'
for 64bit bi-arch (Linux) systems.

   To make a usable TeX installation, you need (thousands of) support
files in addition to the binaries that are built and installed here.
The support files are maintained completely independently.  The best
basis for dealing with them is the TeX Live (plain text) database and/or
the TeX Live installer.


File: texlive.info,  Node: Source Tree,  Next: Configure Options,  Prev: Building and Installing,  Up: Build System

2.3 The TeX Live Source Tree
============================

The TeX Live source tree is the subtree of the complete TeX Live tree
rooted at 'Build/source' and contains the sources for all TeX Live
executables as well as 'make' rules to build and install them together
with some of their support files.

* Menu:

* Top Levels::                  The Top-Level Directories.
* Library Modules::             Structure of Library Modules.
* Program Modules::             Structure of Program Modules.
* Extending::                   Adding New Modules.


File: texlive.info,  Node: Top Levels,  Next: Library Modules,  Up: Source Tree

2.3.1 The Top-Level Directories
-------------------------------

In general, the TeX Live build system uses the latest released versions
of the GNU build tools, installed directly from the original GNU
releases (e.g., by building them with
   'configure --prefix=/usr/local/gnu'
and having 'PATH' start with '/usr/local/gnu/bin').  Currently these are

     autoconf (GNU Autoconf) 2.69
     automake (GNU automake) 1.14
     ltmain.sh (GNU libtool) 2.4.2
     bison (GNU Bison) 3.0
     flex 2.5.37
     m4 (GNU M4) 1.4.17

These versions should be used to update the generated files (e.g.,
'configure' or 'Makefile.in') in all or parts of the TeX Live tree when
some of their sources have been changed.  This can be done explicitly
with the top-level 'reautoconf' script or implicitly by using the
configure option '--enable-maintainer-mode'.

   The subdirectories 'm4', 'build-aux', and 'am' contain 'M4' macros,
auxiliary shell scripts, and 'Makefile.am' fragments respectively, all
of them used in many places.

   The file 'm4/kpse-pkgs.m4' contains lists of all program and library
modules; missing modules are, however, silently ignored.  Each such
module contributes fragments defining its capabilities and requirements
to the 'configure.ac' scripts at the top-level and in the
subdirectiories 'libs', 'utils', and 'texk'.  The fragments from program
modules supply configure options to disable or enable building them,
those from library modules specify if an installed (system) version of
that library can be used.  This decides which modules need to be built,
although all modules must be configured for the benefit of 'make'
targets such as 'dist' or 'distcheck'.

   The subdirectory 'extra' contains things which are not part of the
TeX Live build, but are present for convenience, e.g., 'epstopdf'
developed here or 'xz' required by the TeX Live installer.


File: texlive.info,  Node: Library Modules,  Next: Program Modules,  Prev: Top Levels,  Up: Source Tree

2.3.2 Structure of Library Modules
----------------------------------

The structure of library modules is best explained with a few examples.

2.3.2.1 The 'png' library in 'libs/libpng'
..........................................

This generic library uses the distributed source tree in, e.g.,
'libpng-1.5.17' with all modifications recorded in
'libpng-1.5.17-PATCHES/*'.  The 'configure.ac' fragment
'ac/withenable.ac' contains

     KPSE_WITH_LIB([libpng], [zlib])

with the module name and indicating the dependency on 'zlib'.  A third
argument 'tree' would specify that the library from the TeX Live tree
can not be replaced by a system version.  That not being the case, a
second fragment 'ac/libpng.ac' contains

     KPSE_TRY_LIB([libpng],
                  [#include <png.h>],
                  [png_structp png; png_voidp io; png_rw_ptr fn;
     png_set_read_fn(png, io, fn);])

and provides the simple C code

     #include <png.h>
     int main ()
     { png_structp png; png_voidp io; png_rw_ptr fn;
       png_set_read_fn(png, io, fn);
       return 0; }

used to verify the usability of a system version.  The similar macro
'KPSE_TRY_LIBXX' would provide some C++ code.  These fragments are
included by 'configure.ac' at the top levels.

   A proxy build system consisting of 'configure.ac' and 'Makefile.am'
bypasses the distributed one and consequently a few generated files and
auxiliary scripts are removed from the distributed source tree.

   The module is supplemented by the file 'm4/kpse-libpng-flags.m4' that
defines the 'M4' macro 'KPSE_LIBPNG_FLAGS' used by all modules depending
on this library in their 'configure.ac' to generate the 'make' variables
'LIBPNG_INCLUDES' for use in 'CPPFLAGS', 'LIBPNG_LIBS' for use in
'LDADD', 'LIBPNG_DEPEND' for use as dependency, and 'LIBPNG_RULE'
defining 'make' rules to rebuild the library.

   In addition 'm4/kpse-libpng-flags.m4' supplies the configure option
'--with-system-libpng' and uses 'pkg-config' to determine the flags
required for the system library.

2.3.2.2 The 'zlib' library in 'libs/zlib'
.........................................

This generic library is quite analogous to 'libpng' but does not depend
on any other library.  The file 'm4/kpse-zlib-flags.m4' supplies the
configure option '--with-system-zlib' as well as '--with-zlib-includes'
and '--with-zlib-libdir' to specify non standard locations of the 'zlib'
headers and/or library.

2.3.2.3 The 'freetype' library in 'libs/freetype2'
..................................................

In this case 'configure.ac' is almost trivial and 'Makefile.am' is a
wrapper that invokes 'configure' and 'make' of the distributed source,
followed by 'make install' with the build tree as destination.  The
flags required for the system library are obtained through
'freetype-config'.

2.3.2.4 The 'kpathsea' library in 'texk/kpathsea'
.................................................

This is one of the TeX specific libraries that are maintained as part of
TeX Live.  Other than the generic libraries they are (static and/or
shared) Libtool libraries and are installed together with the programs.
They are, however, not part of the TeX Live DVD as distributed by TeX
user groups.

   It is possible, although quite unusual to specify the configure
option '--with-system-kpathsea' in order to use a system version of the
library and it may then be necessary to specify
'--with-kpathsea-includes' and/or '--with-kpathsea-libdir'.

   In addition to 'ac/withenable.ac' and 'ac/kpathsea.ac' there is a
third fragment 'ac/mktex.ac' included by both 'ac/withenable.ac' and
'configure.ac' that supplies configure options such as
'--enable-mktextfm-default' determining the compile time default whether
or not to run 'mktextfm' to generate a missing '.tfm' file.  Note,
however, that this can be changed by the command line options
'-mktex=tfm' and '-no-mktex=tfm' for TeX-like engines.


File: texlive.info,  Node: Program Modules,  Next: Extending,  Prev: Library Modules,  Up: Source Tree

2.3.3 Structure of Program Modules
----------------------------------

The structure of program modules is again best explained with a few
examples.

2.3.3.1 The 't1utils' package in 'utils/t1utils'
................................................

Once again we use the distributed source tree 't1utils-1.37' with
modifications documented in 't1utils-1.37-PATCHES/*' and a proxy build
system consisting of 'configure.ac' and 'Makefile.am'.  The fragment
'ac/withenable.ac' contains

     KPSE_ENABLE_PROG([t1utils])

specifying the module name without any dependencies and supplies the
configure option '--disable-t1utils'.

2.3.3.2 The 'xindy' package in 'utils/xindy'
............................................

This module uses the distributed source tree 'xindy-2.4' with
modifications documented in 'xindy-2.4-PATCHES/*', a proxy
'configure.ac', and a 'Makefile.am' that descends into 'xindy-2.4'.  The
fragment 'ac/withenable.ac' contains

     KPSE_ENABLE_PROG([xindy], , [disable native])
     m4_include(kpse_TL[utils/xindy/ac/xindy.ac])
     m4_include(kpse_TL[utils/xindy/ac/clisp.ac])

where 'disable' in the third argument indicates that 'xindy' is only
built if explicitly enabled by '--enable-xindy' (because it requires
'clisp') and 'native' disallows cross compilation.  The additional
fragments 'ac/xindy.ac' and 'ac/clisp.ac' specify more configure options
to be seen at the top-leved with 'ac/xindy.ac' also included by
'configure.ac'.

2.3.3.3 The 'xdvik' package in 'texk/xdvik'
...........................................

This package is maintained as part of the TeX Live tree with sources in
its top-level and the subdirectory 'gui'.  The fragment
'ac/withenable.ac' contains

     dnl extra_dirs = texk/xdvik/squeeze
     KPSE_ENABLE_PROG([xdvik], [kpathsea freetype2], [x])
     m4_include(kpse_TL[texk/xdvik/ac/xdvik.ac])

and specifies the dependency on the 'kpathsea', 'freetype', and 'X11'
libraries.  The 'M4' comment (following 'dnl') signals the subsidiary
'squeeze/configure.ac'.  This is needed because the main executable
'xdvi-bin' (to be installed as, e.g., 'xdvi-xaw') is for the 'host'
system whereas the auxiliary program 'squeeze/squeeze' has to run on the
'build' system and in a cross compilation they differ.  The additional
fragment 'ac/xdvik.ac' is also included by 'configure.ac' and supplies
the configure option '--with-xdvi-x-toolkit' also seen at the top-level.

2.3.3.4 The subdirectory 'utils/asymptote'
..........................................

This subdirectory contains the sources for 'asy' and 'xasy' but due to
its complexity and prerequisites (e.g., 'libGL') it is not part the TeX
Live build system.  These programs must be built and installed
independently, but are contained in the TeX Live DVD together with their
support files.


File: texlive.info,  Node: Extending,  Prev: Program Modules,  Up: Source Tree

2.3.4 Adding New Modules
------------------------

2.3.4.1 Adding a New Program Module
...................................

A TeX specific program module in a subdirectory 'texk/PROG' may use the
TeX specific libraries and is included by adding its name 'PROG' to the
'M4' list 'kpse_texk_pkgs' defined in 'm4/kpse-pkgs.m4'.  A generic
program module in a subdirectory 'utils/PROG' must not use the TeX
specific libraries and is included by adding its name 'PROG' to the 'M4'
list 'kpse_utils_pkgs' in 'm4/kpse-pkgs.m4'.  Apart from the program
sources and build system ('configure.ac' and 'Makefile.am') the
subdirectory 'texk/PROG' or 'utils/PROG' must provide a fragment
'ac/withenable.ac' that contains the 'M4' macro 'KPSE_ENABLE_PROG'
defined in 'm4/kpse-setup.m4' with 'PROG' as mandatory first argument
and three optional arguments: a list of required libraries from the TeX
Live tree, a list of options ('disable' if this module is not to be
built without the configure option '--enable-PROG', 'native' if cross
compilation is not possible, 'x' if the program requires X11 libraries),
and a comment added to the help text for the configure option
'--enable-PROG' or '--disable-PROG'.

   If the module requires specific configure options to be seen at the
top-level, they should be defined in an additional fragment 'ac/PROG.ac'
included from 'ac/withenable.ac' and 'configure.ac'.

2.3.4.2 Adding a New Generic Library Module
...........................................

A generic library module in a subdirectory 'libs/LIB' must not depend on
TeX specific libraries and is included by adding its name 'LIB' to the
'M4' list 'kpse_libs_pkgs' in 'm4/kpse-pkgs.m4' (before other libraries
from the TeX Live tree it depends on).  As for program modules the
subdirectory 'libs/LIB' must contain the sources and build system for
the library (and any installable support programs) and a fragment
'ac/withenable.ac' that contains the 'M4' macro 'KPSE_WITH_LIB' defined
in 'm4/kpse-setup.m4' with 'LIB' as mandatory first argument and two
optional arguments: a list of required libraries from the TeX Live tree,
and a list of options (currently only 'tree' if this library can not be
replaced by a system version).

   If a system version can be used, a second fragment 'ac/LIB.ac'
containing the 'M4' macro 'KPSE_TRY_LIB' (or 'KPSE_TRY_LIBXX') with
'LIB' as mandatory first argument and two additional arguments for the
Autoconf macro 'AC_LANG_PROGRAM' used to compile and link a small C (or
C++) program as sanity check for using the system library.

   In addition a file 'm4/kpse-LIB-flags' (at the top-level) must define
the 'M4' macro 'KPSE_LIB_FLAGS' (all uppercase) setting up the 'make'
variables 'LIB_INCLUDES', 'LIB_LIBS', 'LIB_DEPEND', and 'LIB_RULE' with
the values required for 'CPPFLAGS', 'LDADD', dependencies, and a
(multiline) make rule to rebuild the library when necessary, all that
for the library from the TeX Live tree or perhaps for a system version.

   If a system library is allowed 'KPSE_LIB_FLAGS' also provides the
configure option '--with-system-LIB' and uses the additional 'M4' macro
'KPSE_LIB_SYSTEM_FLAGS' to generate the 'make' variables for a system
library.  Furthermore the definition of the 'M4' macro
'KPSE_ALL_SYSTEM_FLAGS' in 'm4/kpse-pkgs.m4' must be extended by the
line
   'AC_REQUIRE([KPSE_LIB_SYSTEM_FLAGS])'

2.3.4.3 Adding a New TeX Specific Library Module
................................................

A TeX specific library module in a subdirectory 'texk/LIB' may depend on
other TeX specific libraries but must not depend on any generic library
from the TeX Live tree.  It is included as is a generic library module
with these modifications:

   * The library name 'LIB' is added to the 'M4' list
     'kpse_texlibs_pkgs' also in 'm4/kpse-pkgs.m4'.

   * The fragment 'ac/withenable.ac' must use 'KPSE_WITH_TEXLIB'.


File: texlive.info,  Node: Configure Options,  Next: Cross Compilation,  Prev: Source Tree,  Up: Build System

2.4 List of all Configure Options
=================================

Corresponding to the large number of program and library modules there
are plenty of configure options, most of which are described here.  The
command
   'configure --help'
at the top-level gives an exhaustive list of all global options and a
few important module specific ones, whereas, e.g.,
   'texk/lcdf-typetools/configure --help'
also displays the 'lcdf-typetools' specific options not shown at the
top-level.  Defaults for most options are set at the top-level and
propagated explicitly to all subdirectories.  Options specified on the
command line are checked for consistency but are never modified.

   In addition the 'configure' command line may contain assignments for
important variables.

* Menu:

* Global Options::              Global Configure Options.
* Program Specific Options::    Configure Options for Program Modules.
* Library Specific Options::    Configure Options for Library Modules.
* Variable Assignments::        Interesting and/or Important Variables.


File: texlive.info,  Node: Global Options,  Next: Program Specific Options,  Up: Configure Options

2.4.1 Global Configure Options
------------------------------

2.4.1.1 '--disable-native-texlive-build'
........................................

If enabled (the default), build for a TeX Live binary distribution as
shipped by the user groups; this requires GNU make and implies
'--enable-multiplatform' and '--enable-cxx-runtime-hack' unless they are
explicitly disabled and enforces '--disable-shared'.

   If building TeX Live for a GNU/Linux or other distribution, this
would be disabled and system versions of most libraries would be used
(see below).  This may require GNU make, but will also try without it.

   A related option '--enable-texlive-build' is automatically passed to
all subdirectories (and can not be disabled).  Subdirectories that could
also be built independent from the TeX Live tree (such as 'utils/xindy'
or 'texk/dvipng') can use this option, e.g., to choose TeX Live specific
installation directories.

2.4.1.2 '--prefix', '--exec-prefix', '--bindir', ...
....................................................

These options specify various installation directories as usual, all of
them still prefixed by the value of an assignment for 'DESTDIR' on the
'make' command line (*note Installation in a temporary location:
(automake)Staged Installs.).

2.4.1.3 '--enable-multiplatform'
................................

If enabled, install executables and libraries in platform dependent
subdirectories of 'EPREFIX/bin' and 'EPREFIX/lib' (unless '--bindir=DIR'
or '--libdir=DIR' is specified), where 'EPREFIX' is the value given or
implied for 'exec_prefix'.  The values for 'bindir' and 'libdir' are
automatically propagated to all subdirectories.

2.4.1.4 '--enable-cxx-runtime-hack'
...................................

If enabled and when using 'g++', try to statically link with
'libstdc++', somewhat improving portability.

2.4.1.5 '--enable-libtool-hack'
...............................

If enabled (at present the default for all platforms), prevents
'libtool' from linking explicitly with 'dependency_libs'.

2.4.1.6 '--enable-shared'
.........................

Build shared versions of the TeX specific ('kpathsea' and 'ptexenc')
libraries; this is not allowed for a native TeX Live build.

2.4.1.7 '--disable-largefile'
.............................

Omit large file support (LFS), needed on most 32-bit Unix systems for
files with 2GB or more.  The size of 'DVI' and 'GF' files must always be
<2GB. With LFS there should be no limit on the size of 'PDF' files
created by 'pdftex' or 'PS' files created by 'dvips'.  The size of 'PDF'
images included by 'pdftex' must, however, be <4GB when using 'xpdf' and
<2GB when using older versions of 'poppler' (even on 64-bit systems with
LFS), whereas 'poppler' Version 0.23 and later imposes such no limit.

2.4.1.8 '--without-x'
.....................

Disable all programs using the X Window System.

2.4.1.9 '--enable-compiler-warnings=[no|min|yes|max|all]'
.........................................................

Enable various degrees of compiler warnings for (Objective) C and C++.
The default is 'yes' in maintainer-mode and 'min' otherwise.  This
option defines 'WARNING_[OBJ]C[XX]FLAGS' but these flags are not used in
all library and program modules.  Using them should help to resolve
portability problems.

   At the moment these warning flags are only defined for the GNU
compilers but flags for other compilers could be added when needed.

2.4.1.10 '--disable-missing'
............................

Immediately terminate the build process if a requested program or
feature must be disabled, e.g., due to missing libraries.

2.4.1.11 '--enable-silent-rules'
................................

Enable the use of less verbose build rules.  When using GNU make or
another 'make' implementation that supports nested variable expansions
you can always specify 'V=1' on the make command line to get more
respectively 'V=0' to get less verbosity.

2.4.1.12 '--without-ln-s'
.........................

Required to build without working 'ln -s' for a Unix-like system.  But
note that 'make install' will not create anything useful and might even
fail.

2.4.1.13 '--enable-maintainer-mode'
...................................

Enable 'make' rules and dependencies not useful (and sometimes
confusing) to the casual user.  This requires current versions of the
GNU build tools.


File: texlive.info,  Node: Program Specific Options,  Next: Library Specific Options,  Prev: Global Options,  Up: Configure Options

2.4.2 Configure Options for Program Modules
-------------------------------------------

2.4.2.1 '--enable-PROG', '--disable-PROG'
.........................................

Do or do not build and install the program(s) of the module 'PROG'.

2.4.2.2 '--disable-all-pkgs'
............................

Do not build any program modules, except those explicitly enabled.
Without this option, all modules are built except those that are
explicitly disabled or specify 'disable' in their 'ac/withenable.ac'
fragment.

2.4.2.3 Configure options for 'texk/web2c'
..........................................

'--with-banner-add=STR'
Add 'STR' to the default version string ('TeX Live YEAR' or 'Web2C
YEAR') appended to banner lines.  This is ignored for a native TeX Live
build, but distro builds should specify, e.g., '/SOMEDISTRO'.

'--with-editor=CMD'
Specify the command 'CMD' to invoke from the 'e' option of TeX-like
engines, replacing the default 'vi +%d '%s'' for Unix or 'texworks
--position=%d "%s"' for Windows.

'--enable-auto-core'
This option causes TeX & METAFONT to produce a core dump when a
particular hacky filename is encountered.

'--disable-dump-share'
Make the 'fmt'/'base' dump files architecture dependent (somewhat faster
on little-endian architectures).

'--disable-ipc'
Disable TeX's '--ipc' option.

'--disable-tex', '--enable-etex', ...
Do not or do build the various TeX, METAFONT, and MetaPost engines
(defaults are defined in the fragment 'texk/web2c/ac/web2c.ac').

'--enable-tex-synctex', '--disable-etex-synctex', ...
Build the various TeX-like engines with or without 'SyncTeX' support
(ignored for a native TeX Live build, defaults are again defined in
'texk/web2c/ac/web2c.ac').

'--with-mf-x-toolkit'
Use the X toolkit ('libXt') for METAFONT (default is yes).

'--enable-*win'
Include various types of other window support for METAFONT.

'--disable-mf-nowin'
Do not build a separate non-graphically-capable METAFONT.

'--disable-web-progs'
Do not build the WEB programs 'bibtex', ..., 'weave', e.g., if you just
want to (re)build some engines.

'--disable-omfonts'
Build the WEB versions of the Omega font utilities 'ofm2opl', 'opl2ofm',
'ovf2ovp', and 'ovp2ovf' instead of the C version 'omfonts'.  The WEB
and C versions should be roughly equivalent.

2.4.2.4 Configure options for 'texk/bibtex-x'
.............................................

The former modules 'bibtex8' and 'bibtexu' have been merged into
'bibtex-x' (extended BibTeX).

'--disable-bibtex8'
Do not build the 'bibtex8' program.

'--disable-bibtexu'
Do not build the 'bibtexu' program (building 'bibtexu' requires 'ICU'
libraries).

2.4.2.5 Configure options for 'texk/dvipdfm-x'
..............................................

The former modules 'dvipdfmx' and 'xdvipdfmx' have been merged into
'dvipdfm-x'.

'--disable-dvipdfmx'
Do not build the 'dvipdfmx' program.

'--disable-xdvipdfmx'
Do not build the 'xdvipdfmx' program (building 'xdvipdfmx' requires the
'freetype' library).

2.4.2.6 Configure options for 'texk/dvisvgm'
............................................

'--with-system-libgs'
Build 'dvisvgm' using installed Ghostscript ('gs') headers and library
(not allowed for a native TeX Live build).  The default is to load the
'gs' library at runtime if possible, or otherwise disable support for
PostScript specials.

'--with-libgs-includes=DIR', '--with-libgs-libdir=DIR'
Specify non standard locations of the Ghostscript headers and library.

2.4.2.7 Configure options for 'texk/xdvik'
..........................................

'--with-gs=PATH'
Hardwire the location of Ghostscript ('gs').

'--with-xdvi-x-toolkit=KIT'
Use toolkit 'KIT' ('motif'/'xaw'/'xaw3d'/'neXtaw') for 'xdvi'.  The
default is 'motif' if available, else 'xaw'.

2.4.2.8 Configure options for 'utils/xindy'
...........................................

'--enable-xindy-rules'
Build and install xindy rules (default: yes, except for a native TeX
Live build).

'--enable-xindy-docs'
Build and install xindy documentation (default: yes, except for a native
TeX Live build).

'--with-clisp-runtime=PATH'
Specifies the full path of the 'CLISP' runtime ('lisp.run' or
'lisp.exe') to be installed.  When specified as 'default' (the default
for a native TeX Live build) the path is determined by the 'CLISP'
executable; the value 'system' (not allowed for a native TeX Live build,
but the default for a non-native one) indicates that 'xindy' will use
the installed version of 'clisp' (that must be identical to the one used
to build 'xindy').

'--with-recode'
Use 'recode' instead of 'iconv' to build the xindy rules and
documentation, required for some systems where 'iconv' is missing or
broken.


File: texlive.info,  Node: Library Specific Options,  Next: Variable Assignments,  Prev: Program Specific Options,  Up: Configure Options

2.4.3 Configure Options for Library Modules
-------------------------------------------

2.4.3.1 '--with-system-LIB'
...........................

Use an installed (system) version of the library 'LIB'; this option
exists for most libraries, but is not allowed for a native TeX Live
build.  Using a system version implies to also use system versions of
all libraries (if any) this library depends on.

   For many libraries there are in addition '--with-LIB-includes=DIR'
and '--with-LIB-libdir=DIR' to indicate non standard search locations,
others use 'pkg-config' or similar to determine the required flags.

   The top-level 'configure' script performs a consistency check for all
required system libraries and bails out if some of these tests fail.

2.4.3.2 Configure Options for 'kpathsea'
........................................

'--enable-CMD-default', '--disable-CMD-default'
Determine the compile time default whether or not to run CMD='mktexmf',
'mktexpk', 'mktextfm', 'mkocp', 'mkofm', 'mktexfmt', or 'mktextex' to
generate a missing MF source, PK font, TFM file, OCP file, OFM file,
format file, or TeX source respectively.

2.4.3.3 Configure Options for 'fontconfig'
..........................................

Building 'XeTeX' on non-Mac systems requires 'fontconfig' headers and
library.

'--with-fontconfig-includes=DIR', '--with-fontconfig-libdir=DIR'
If one or both of these options are given, the required flags are
derived from them; otherwise, they are determined via 'pkg-config' (if
present).

2.4.3.4 Configure Options for system 'poppler'
..............................................

Building 'LuaTeX' and 'XeTeX' requires 'poppler' either from the TeX
Live tree or system headers and library; 'pdfTeX' requires either 'xpdf'
from the TeX Live tree or system 'poppler' headers and library.

'--with-system-poppler'
Use a system version (0.18 or better) of 'poppler' for 'LuaTeX' and
'XeTeX' (and 'pkg-config' to obtain the required flags).

'--with-system-xpdf'
Use a system version (0.12 or better) of 'poppler' (and 'pkg-config')
for 'pdfTeX' instead of 'xpdf' from the TeX Live tree.

   REFER to '--disable-largefile'


File: texlive.info,  Node: Variable Assignments,  Prev: Library Specific Options,  Up: Configure Options

2.4.4 Interesting and/or Important Variables
--------------------------------------------

The values for these variables can come either from the environment or
from 'configure' arguments of the form 'VAR=value'.

2.4.4.1 'CC', 'CXX', 'CPPFLAGS', ...
....................................

As usual, these variables specify the name (or full path) of compilers,
preprocessor flags, and similar.

2.4.4.2 'FT2_CONFIG', 'ICU_CONFIG', 'PKG_CONFIG'
................................................

These specify the name (or path) for the 'freetype-config',
'icu-config', and 'pkg-config' commands used to determine the flags
required for system versions of 'libfreetype', the 'ICU' libraries, or
many other libraries.

2.4.4.3 'CLISP'
...............

Name (or path) of the 'clisp' executable, used to build 'xindy'.

2.4.4.4 'PERL', 'LATEX', 'PDFLATEX'
...................................

Name (or path) for the 'perl', 'latex', and 'pdflatex' commands used,
e.g., to build the 'xindy' documentation

2.4.4.5 'TL_PLATFORM'
.....................

The utility program 'biber' consists of many components bundled by the
'Par::Packer' mechanism of 'perl'.  Therefore they are not built as part
of TeX Live but by the 'biber' maintainers and third-party builders.

   In order that 'make install' creates all executables in 'bindir', the
'biber' module contains pre-made binaries for the platforms for which
they are available.  TeX Live merely checks if an executable is present
for the current platform, and if so, installs it.

   The complication is hidden in the phrase "current platform".  TeX
Live has its own ideas about platform names, and the mapping from the
canonical system name determined by 'config.guess' or 'config.sub' to
the TeX Live platform name is not trivial.  A value given for
'TL_PLATFORM' is used as TeX Live platform name.  Otherwise, we use
copies of the standard 'perl' modules 'TeXLive/TLUtils.pm' and
'TeXLive/TLConfig.pm', to avoid duplicating the platform-detection
logic.

2.4.4.6 'KPSEWHICH'
...................

Name (or path) of an installed 'kpsewhich' binary, used by 'make check'
to determine the location of, e.g., 'cmbx10.tfm'.

2.4.4.7 'MAKE', 'SED', ...
..........................

Name (or path) of GNU make, GNU sed, and similar; used at the top-level
and propagated to all subdirectories.


File: texlive.info,  Node: Cross Compilation,  Next: Coding Rules,  Prev: Configure Options,  Up: Build System

2.5 Cross Compilation
=====================

In a cross compilation a 'build' system is used to create binaries to be
executed on a 'host' system with different hardware and/or operating
system.

   In simple cases the build system can execute binaries for the host
system.  This typically occurs for bi-arch systems where, e.g.,
'i386-linux' binaries can run on 'x86_64-linux' systems and 'win32'
binaries can run on 'win64' systems.  Although sometimes called "native
cross", this is technically no cross compilation.  In most such cases it
suffices to specify suitable compiler flags.  It might be useful to add
the configure option '--build=HOST' to get the correct canonical host
name, but note that this should not be '--host=HOST' (*note
(autoconf)Hosts and Cross-Compilation::)!

* Menu:

* Configuring::                 Configuring for Cross Compilation.
* Problems::                    Cross Compilation Problems.


File: texlive.info,  Node: Configuring,  Next: Problems,  Up: Cross Compilation

2.5.1 Configuring for Cross Compilation
---------------------------------------

In a genuine cross compilation binaries for the host system can not
execute on the build system and it is necessary to specify the configure
options '--host=HOST' and '--build=BUILD' with two different values.
Building binaries requires suitable "cross" tools, e.g., compiler,
linker, and archiver, and perhaps a "cross" version of 'pkg-config' and
similar to locate host system libraries.  Autoconf expects that these
cross tools are given by their usual variables or found under their
usual name prefixed with 'HOST-'.  Here a list of such tools and
corresponding variables:

     ar                AR
     freetype-config   FT2_CONFIG
     g++               CXX
     gcc               CC
     icu-config        ICU_CONFIG
     objdump           OBJDUMP
     pkg-config        PKG_CONFIG
     ranlib            RANLIB
     strip             STRIP

In order to, e.g., build 'mingw32' binaries on 'x86_64-linux' with a
cross compiler found as 'i386-pc-mingw32-gcc' one would specify
   '--host=i386-pc-mingw32 --build=x86_64-linux-gnu'
or perhaps
   '--host=mingw32 --build=x86_64-linux CC=i386-pc-mingw32-gcc'
but this might require to add 'CXX' and others.

   Configure arguments such as 'CFLAGS=...' refer to the cross compiler.
If necessary, you can specify compilers and flags for the few auxiliary
C and C++ programs required for the build process as configure arguments

     BUILDCC=...
     BUILDCPPFLAGS=...
     BUILDCFLAGS=...
     BUILDCXX=...
     BUILDCXXFLAGS=...
     BUILDLDFLAGS=...


File: texlive.info,  Node: Problems,  Prev: Configuring,  Up: Cross Compilation

2.5.2 Cross Compilation Problems
--------------------------------

The fact that binaries for the host system can not be executed on the
build system causes some problems.

   One problem is, that configure tests using 'AC_RUN_IFELSE' can
compile and link the test program but can not execute it.  Such tests
should be avoided if possible and otherwise must supply a pessimistic
test result.

   An other problem arises if the build process must execute some
(auxiliary or installable) programs.  Auxiliary programs can be placed
into a subdirectory that is configured natively as is done for
'texk/dvipsk/squeeze', 'texk/web2c/web2c', and 'texk/xdvik/squeeze'.
The module 'libs/freetype' uses the value of 'CC_BUILD', 'BUILD-gcc',
'gcc', or 'cc' as compiler for the auxiliary program.

   The situation for installable programs needed by the build process is
somewhat different.  A quite expensive possibility, chosen for the 'ICU'
libraries in module 'libs/icu', is to first compile natively for the
build system and in a second step to use these (uninstalled) programs
during the cross compilation.  This would also be possible for the tools
such as 'tangle' used in the module 'texk/web2c' to build the WEB
programs, but that would require to first build a native 'kpathsea'
library.  To avoid this complication, cross compilation of the WEB or
CWEB programs in this module requires sufficiently recent installed
versions of 'tangle', 'ctangle', 'otangle', and 'tie'.

   Building 'xindy' requires to run the host system 'clisp' binary, thus
cross compilation is not possible.


File: texlive.info,  Node: Coding Rules,  Prev: Cross Compilation,  Up: Build System

2.6 Coding Rules
================

2.6.1 Declarations
------------------

2.6.1.1 ANSI C function prototypes and definitions
..................................................

The TeX Live build system no longer supports pre-ANSI C compilers.  Thus
all function prototypes and definitions must conform to the ANSI C
standard (including 'void' in the declaration of C functions with no
parameters).  On the other hand TeX Live is built for many different
systems, some of them not supporting the C99 standard.  Therefore using
C99 features should be avoided if that can easily be done.  In
particular C code must not contain declarations after statements or C++
type comments.

   If some C99 (or later) constructs have to be used, the module should
verify that they are available and otherwise provide an alternative.
The module 'texk/chktex' uses, e.g., the C99 function 'stpcpy()' that
may or may not be available on a particular system, uses
'AC_CHECK_DECLS([stpcpy])' in 'configure.ac' to test this, and provides
the perhaps slightly less efficient alternative
   '#if !(defined HAVE_DECL_STPCPY && HAVE_DECL_STPCPY)'
   'static inline char * stpcpy(char *dest, const char *src)'
   '{'
   '   return strcpy(dest, src) + strlen(src);'
   '}'
   '#endif'
in the file 'Utility.h'.

2.6.1.2 Static Functions
........................

Functions used in only one file should be declared 'static'; they
require no prototype except as forward declaration.

2.6.1.3 Extern Functions
........................

Functions not declared 'static', usually because they are used in
several files, require an ('extern') prototype in exactly one header
which is included in the file defining the function and in all files
using that function -- this is the only way to guarantee consistency
between definition and use of functions.  You must not have 'extern'
declarations sprinkled throughout the C code (with or without comment
where that function is defined).

2.6.1.4 Variables
.................

The declaration of global variables must follow analogous rules, they
are either declared 'static' if used in only one files or declared
'extern' in exactly one header and instantiated in exactly one file.

2.6.2 Const
-----------

2.6.2.1 Function Parameters
...........................

Ideally, a function parameter not modified by the function should be
declared as 'const'.  This is important in particular for strings
('char*') because the actual arguments are often string literals.  It is
perfectly legitimate and safe to use a type 'char*' value for a type
'const char*' variable (in an assignment, as initializer, as function
argument, or as return value).  It is equally safe to use a type
'char**' value for a type 'const char*const*' variable, but not for a
type 'const char**' variable since that might cause modification of a
quantity supposed to be constant.  Getting all 'const' qualifiers right
is often quite involved but can be done in most cases.  There are,
however, a few notable exceptions: the X11 headers are full of
declarations that ought to use 'const' but do not and the same is true
to some extent for 'libfreetype' (but not anymore for 'zlib').

2.6.2.2 What Must be Avoided
............................

The 'gcc' compiler warnings "assignment discards qualifiers..." and
analogous warnings for "initialization", "passing arg", or "return" must
be avoided under all circumstances, except when caused by X11
headers/macros or third party code.

2.6.2.3 What Should be Avoided
..............................

A type cast, e.g., from 'const char*' to 'char*' does not solve any
problems; depending on warning options, it may only hide them.
Therefore such casts should be avoided whenever possible and otherwise
must be carefully analyzed to make sure that they can not cause the
modification of quantities supposed to be constant.


File: texlive.info,  Node: Index,  Prev: Build System,  Up: Top

Index
*****