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author | Peter Breitenlohner <peb@mppmu.mpg.de> | 2009-11-10 14:02:38 +0000 |
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committer | Peter Breitenlohner <peb@mppmu.mpg.de> | 2009-11-10 14:02:38 +0000 |
commit | 7b75da706bf852114d792cf3b0f3c73ae0ca0fb8 (patch) | |
tree | c76bdff652167455b3e9534bedf558ae88a3dcdb /Build/source/README.coding | |
parent | 84ef24a5151f308cbe96edd705d1cdedd98a4210 (diff) |
directories not used for build moved to extra/
git-svn-id: svn://tug.org/texlive/trunk@15980 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/README.coding')
-rw-r--r-- | Build/source/README.coding | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/Build/source/README.coding b/Build/source/README.coding new file mode 100644 index 00000000000..fe7edbd3209 --- /dev/null +++ b/Build/source/README.coding @@ -0,0 +1,70 @@ +Copyright (C) 2009 Peter Breitenlohner <tex-live@tug.org> +You may freely use, modify and/or distribute this file. + + TeX Live (TL) coding rules + ========================== + +Ideally, building all of TL with '--enable-compiler-warnings=max' should +produce no (gcc) compiler warnings at all. In spite of considerable efforts +into that direction we are still far from that goal and there are reasons +that we may never fully reach it. Below are some rules about declarations +(of functions and variables) and the use of const. These rules should be +applied to all parts of the TL tree, except in some of those maintained +independently. + +1. Declarations +=============== + +1.1. ANSI C function prototypes and definitions +----------------------------------------------- +The TL build system no longer supports pre-ANSI C compilers. Thus all +functions prototypes and definitions must conform to the ANSI C standard +(including 'void' in the declaration of functions that take no parameters). + +1.2. Static +----------- +Functions used in only one file must be declared 'static'; no prototype is +required except as forward declaration. + +1.3. Extern +----------- +Functions used in several files require (extern) prototypes to be provided +by a header files. That header must be 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. No more +'extern's sprinkled throughout the C code (with or without comment where +that function is defined). + +1.4. Variables +-------------- +The declaration of global variables should follow analogous rules, they +should either be static or declared extern in a header and instatiated in +exectly one file. + +2. Const +======== + +2.1. Function parameters +------------------------ +Ideally, a function parameter not modified by the function should be +declared as const. This is important in particiular for strings ('char *') +because frequently string literals are used as actual arguments. Note, +however, that a 'char **' value is not assignment compatible with a 'const +char **' variable. Getting all 'const's right often is quite involved but +usually can be done. 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 zlib. + +2.2. What must be avoided +------------------------- +The compiler warnings 'assignment/initialization/passing arg/return discards +qualifiers...' must be avoided under all circumstances, except when caused +by X11 headers/macros or third party code. + +2.3. What should be avoided +--------------------------- +A type cast, e.g., from 'const char *' to 'char *' doesn't solve any +problems, depending on warning options it only may hide them. Therefore +such casts should be avoided whenever possible but some such casts may be +unavoidable. + |