diff --git a/doc/developer.texi b/doc/developer.texi index cf918ac6b1..8e6d9d8730 100644 --- a/doc/developer.texi +++ b/doc/developer.texi @@ -56,6 +56,58 @@ and should try to fix issues their commit causes. @anchor{Coding Rules} @chapter Coding Rules +@section C language features + +FFmpeg is programmed in the ISO C90 language with a few additional +features from ISO C99, namely: + +@itemize @bullet +@item +the @samp{inline} keyword; + +@item +@samp{//} comments; + +@item +designated struct initializers (@samp{struct s x = @{ .i = 17 @};}); + +@item +compound literals (@samp{x = (struct s) @{ 17, 23 @};}). + +@item +for loops with variable definition (@samp{for (int i = 0; i < 8; i++)}); + +@item +Variadic macros (@samp{#define ARRAY(nb, ...) (int[nb + 1])@{ nb, __VA_ARGS__ @}}); + +@item +Implementation defined behavior for signed integers is assumed to match the +expected behavior for two's complement. Non representable values in integer +casts are binary truncated. Shift right of signed values uses sign extension. +@end itemize + +These features are supported by all compilers we care about, so we will not +accept patches to remove their use unless they absolutely do not impair +clarity and performance. + +All code must compile with recent versions of GCC and a number of other +currently supported compilers. To ensure compatibility, please do not use +additional C99 features or GCC extensions. Especially watch out for: + +@itemize @bullet +@item +mixing statements and declarations; + +@item +@samp{long long} (use @samp{int64_t} instead); + +@item +@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar; + +@item +GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}). +@end itemize + @section Code formatting conventions There are the following guidelines regarding the indentation in files: @@ -121,58 +173,6 @@ int myfunc(int my_parameter) ... @end example -@section C language features - -FFmpeg is programmed in the ISO C90 language with a few additional -features from ISO C99, namely: - -@itemize @bullet -@item -the @samp{inline} keyword; - -@item -@samp{//} comments; - -@item -designated struct initializers (@samp{struct s x = @{ .i = 17 @};}); - -@item -compound literals (@samp{x = (struct s) @{ 17, 23 @};}). - -@item -for loops with variable definition (@samp{for (int i = 0; i < 8; i++)}); - -@item -Variadic macros (@samp{#define ARRAY(nb, ...) (int[nb + 1])@{ nb, __VA_ARGS__ @}}); - -@item -Implementation defined behavior for signed integers is assumed to match the -expected behavior for two's complement. Non representable values in integer -casts are binary truncated. Shift right of signed values uses sign extension. -@end itemize - -These features are supported by all compilers we care about, so we will not -accept patches to remove their use unless they absolutely do not impair -clarity and performance. - -All code must compile with recent versions of GCC and a number of other -currently supported compilers. To ensure compatibility, please do not use -additional C99 features or GCC extensions. Especially watch out for: - -@itemize @bullet -@item -mixing statements and declarations; - -@item -@samp{long long} (use @samp{int64_t} instead); - -@item -@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar; - -@item -GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}). -@end itemize - @section Naming conventions All names should be composed with underscores (_), not CamelCase. For example, @samp{avfilter_get_video_buffer} is an acceptable function name and