[FFmpeg-devel] [PATCHv2] avfilter/buffersrc: add av_warn_unused_result attributes

[Ganesh Ajjanagadde]

On Wed, Oct 7, 2015 at 10:18 AM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
> On Wed, Oct 7, 2015 at 10:01 AM, Clément Bœsch <u at pkh.me> wrote:
>> On Wed, Oct 07, 2015 at 09:31:49AM -0400, Ganesh Ajjanagadde wrote:
>>> On Wed, Oct 7, 2015 at 8:59 AM, Clément Bœsch <u at pkh.me> wrote:
>>> > On Tue, Oct 06, 2015 at 06:53:47PM -0400, Ganesh Ajjanagadde wrote:
>>> >> This adds av_warn_unused_result whenever it is relevant.
>>> >>
>>> >> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>>> >> ---
>>> >>  libavfilter/buffersrc.h | 3 +++
>>> >>  1 file changed, 3 insertions(+)
>>> >>
>>> >> diff --git a/libavfilter/buffersrc.h b/libavfilter/buffersrc.h
>>> >> index cd3d95f..847c093 100644
>>> >> --- a/libavfilter/buffersrc.h
>>> >> +++ b/libavfilter/buffersrc.h
>>> >> @@ -78,6 +78,7 @@ unsigned av_buffersrc_get_nb_failed_requests(AVFilterContext *buffer_src);
>>> >>   * This function is equivalent to av_buffersrc_add_frame_flags() with the
>>> >>   * AV_BUFFERSRC_FLAG_KEEP_REF flag.
>>> >>   */
>>> >> +av_warn_unused_result
>>> >>  int av_buffersrc_write_frame(AVFilterContext *ctx, const AVFrame *frame);
>>> >>
>>> >>  /**
>>> >> @@ -98,6 +99,7 @@ int av_buffersrc_write_frame(AVFilterContext *ctx, const AVFrame *frame);
>>> >>   * This function is equivalent to av_buffersrc_add_frame_flags() without the
>>> >>   * AV_BUFFERSRC_FLAG_KEEP_REF flag.
>>> >>   */
>>> >> +av_warn_unused_result
>>> >>  int av_buffersrc_add_frame(AVFilterContext *ctx, AVFrame *frame);
>>> >>
>>> >>  /**
>>> >> @@ -115,6 +117,7 @@ int av_buffersrc_add_frame(AVFilterContext *ctx, AVFrame *frame);
>>> >>   * @return            >= 0 in case of success, a negative AVERROR code
>>> >>   *                    in case of failure
>>> >>   */
>>> >> +av_warn_unused_result
>>> >>  int av_buffersrc_add_frame_flags(AVFilterContext *buffer_src,
>>> >>                                   AVFrame *frame, int flags);
>>> >>
>>> >
>>> > Aren't you just supposed to (void)-prefix the call in the caller when you
>>> > explicitly don't care about the result?
>>> >
>>> > These functions certainly looks like you actually want to check for the
>>> > result most of the time.
>>>
>>> Exactly - this addition to the declaration in the header will trigger
>>> a warning whenever this function is used without obtaining the return
>>> value.
>>>
>>
>> Oh, my bad, I misunderstood, sounds indeed saner than what I had in mind.
>>
>> Thanks for the clarification.
>
> By the way, I highly encourage all developers to slowly start adding
> this to relevant headers, at least in the things they respectively
> maintain. For instance, a bunch of possible bugs/robustness issues
> will be fixed. Here is one I noticed today: by applying to
> init_get_bits8, a few warnings get triggered. There have been commits
> from Michael addressing some CID's related to this - this will ensure
> a complete weeding out of that particular issue.

ping

>
>>
>> --
>> Clément B.
>>
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