[FFmpeg-devel] [PATCH] Check for the isatty function

[Måns Rullgård]

Martin Storsj? <martin at martin.st> writes:

> On Tue, 14 Jul 2009, Ramiro Polla wrote:
>
>> 2009/7/14 M?ns Rullg?rd <mans at mansr.com>:
>> > Martin Storsj? <martin at martin.st> writes:
>> >
>> >> diff --git a/ffmpeg.c b/ffmpeg.c
>> >> index ca083de..15b1dcd 100644
>> >> --- a/ffmpeg.c
>> >> +++ b/ffmpeg.c
>> >> @@ -3978,8 +3978,10 @@ int main(int argc, char **argv)
>> >> ? ? ?avdevice_register_all();
>> >> ? ? ?av_register_all();
>> >>
>> >> +#if HAVE_ISATTY
>> >> ? ? ?if(isatty(STDIN_FILENO))
>> >> ? ? ? ? ?url_set_interrupt_cb(decode_interrupt_cb);
>> >> +#endif
>> >>
>> >> ? ? ?for(i=0; i<CODEC_TYPE_NB; i++){
>> >> ? ? ? ? ?avcodec_opts[i]= avcodec_alloc_context2(i);
>> >
>> > Fine by me.
>> >
>> > That said, why do we do this only if stdin is a terminal?
>> 
>> I don't know, Michael added that. If we set it unconditionally, won't
>> this interfere with pipe inputs?
>
> Yes, it would probably interfere with pipes.
>
> Another solution would be:
>
> #ifdef HAVE_ISATTY
>     if (isatty(STDIN_FILENO))
> #endif
>         url_set_interrupt_cb(decode_interrupt_cb);
>
> That is, if isatty isn't available, one can perhaps assume that stdin 
> isn't a pipe.
>
> OTOH, the initial version is safer in this aspect. If I understood issue66 
> correctly, this is only needed to be able to abort by pressing 'q' while 
> opening the file, so skipping if it if unsure (as in the initial patch) 
> should be quite safe.

I didn't mean to imply that the patch was wrong.  I just wasn't sure
why the original code was that way in the first place.

-- 
M?ns Rullg?rd
mans at mansr.com