[FFmpeg-devel] [PATCH] fftools/ffmpeg: Fix declaration-after-statement warning

["zhilizhao(赵志立)"]

> On Jul 19, 2021, at 3:23 AM, Andreas Rheinhardt <andreas.rheinhardt at outlook.com> wrote:
> 
> Andreas Rheinhardt:
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
>> ---
>> What is actually the reason that we stick to this C90 rule?
>> Is it because of compability with ancient compilers? (Given that we
>> already require several C99 features, I doubt that there are compilers
>> which would fail if we stopped adhering to the
>> declaration-before-statement rule.) Or is it because it is presumed that
>> it improves clarity and readability?
>> 
> 
> I pushed this to fix the warning, although I'd like to hear other
> peoples' opinion on whether the warning should no longer be enabled.

For clang, `-Wdeclaration-after-statement` has no effect with -std=c99. So now it’s
more difficult to detect the declaration-after-statement case, since there is no compiler
warning message. I prefer to disable the warning.


> 
>> fftools/ffmpeg.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>> 
>> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
>> index e0f2fe138f..6f6e002604 100644
>> --- a/fftools/ffmpeg.c
>> +++ b/fftools/ffmpeg.c
>> @@ -4234,10 +4234,11 @@ static int get_input_packet(InputFile *f, AVPacket **pkt)
>>         float scale = f->rate_emu ? 1.0 : f->readrate;
>>         for (i = 0; i < f->nb_streams; i++) {
>>             InputStream *ist = input_streams[f->ist_index + i];
>> +            int64_t stream_ts_offset, pts, now;
>>             if (!ist->nb_packets) continue;
>> -            int64_t stream_ts_offset = FFMAX(ist->first_dts != AV_NOPTS_VALUE ? ist->first_dts : 0, file_start);
>> -            int64_t pts = av_rescale(ist->dts, 1000000, AV_TIME_BASE);
>> -            int64_t now = (av_gettime_relative() - ist->start)*scale + stream_ts_offset;
>> +            stream_ts_offset = FFMAX(ist->first_dts != AV_NOPTS_VALUE ? ist->first_dts : 0, file_start);
>> +            pts = av_rescale(ist->dts, 1000000, AV_TIME_BASE);
>> +            now = (av_gettime_relative() - ist->start) * scale + stream_ts_offset;
>>             if (pts > now)
>>                 return AVERROR(EAGAIN);
>>         }
>> 
> 
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