avutil/attributes: add av_warn_unused_result

GCC 3.4 introduced an attribute warn_unused_result to warn when a programmer
discards the return value. Applying this judiciously across the codebase can help
in fixing a lot of problems. At a high level, functions which return error codes
should always be checked. More concretely, consider the functions ff_add_format
and the like in avfilter/formats.h. A quick examination shows that a large portion
of libavfilter fails to handle the associated errors, usually AVERROR(ENOMEM).
The above example was where I observed the utility of this, but it should be
useful in many places across the code base.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Ganesh Ajjanagadde 2015-10-05 01:45:12 -04:00 committed by Michael Niedermayer
parent 6f1ccca4ae
commit 1d4af04adf
1 changed files with 6 additions and 0 deletions

View File

@ -52,6 +52,12 @@
#endif
#endif
#if AV_GCC_VERSION_AT_LEAST(3,4)
# define av_warn_unused_result __attribute__((warn_unused_result))
#else
# define av_warn_unused_result
#endif
#if AV_GCC_VERSION_AT_LEAST(3,1)
# define av_noinline __attribute__((noinline))
#elif defined(_MSC_VER)