[FFmpeg-cvslog] Make av_realloc(0) behave like our av_malloc(0)

[Daniel Verkamp]

On Sat, May 7, 2011 at 4:36 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Sat, May 07, 2011 at 11:31:11AM -0700, Daniel Verkamp wrote:
>> On Sat, May 7, 2011 at 7:54 AM, Reimar Döffinger
>> <Reimar.Doeffinger at gmx.de> wrote:
>> >
>> >
>> > On 7 May 2011, at 16:23, git at videolan.org (Michael Niedermayer) wrote:
>> >
>> >> ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat May  7 15:28:07 2011 +0200| [91ff05f6ac5c65a6cd3701d5a7cdcfb6ccfd87e4] | committer: Michael Niedermayer
>> >>
>> >> Make av_realloc(0) behave like our av_malloc(0)
>> >> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
>> >>
>> >>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=91ff05f6ac5c65a6cd3701d5a7cdcfb6ccfd87e4
>> >> ---
>> >>
>> >> libavutil/mem.c |    2 +-
>> >> 1 files changed, 1 insertions(+), 1 deletions(-)
>> >>
>> >> diff --git a/libavutil/mem.c b/libavutil/mem.c
>> >> index 965daa9..83e8c35 100644
>> >> --- a/libavutil/mem.c
>> >> +++ b/libavutil/mem.c
>> >> @@ -132,7 +132,7 @@ void *av_realloc(void *ptr, size_t size)
>> >>     diff= ((char*)ptr)[-1];
>> >>     return (char*)realloc((char*)ptr - diff, size + diff) + diff;
>> >> #else
>> >> -    return realloc(ptr, size);
>> >> +    return realloc(ptr, size + !size);
>> >> #endif
>> >
>> > Not sure if it's such a great idea, but I think you could
>> > use exactly the same code as in av_malloc to avoid doing
>> > something when not necessary.
>>
>> Isn't realloc(ptr, 0) supposed to be free(ptr), or does that not apply
>> to av_realloc?
>
> I thought so too but couldnt find that requirement in the C spec
> The spec says NULL, X should behave like malloc
>

My reference was SUS:
http://pubs.opengroup.org/onlinepubs/007908799/xsh/realloc.html

But I guess it doesn't matter anyway as long as it's documented.

> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB