ffmpeg and mmap

Martin Matuska mm at FreeBSD.org
Sun Dec 12 21:29:01 UTC 2010


Lets see what we can read about this from ffmpeg history:

I tracked it down to this git commit of ffmpeg:
http://git.ffmpeg.org/?p=ffmpeg;a=commit;h=00dd86329f892c6fdf641c4cc8b0497ff232d2e9

The commit ressults from a discussion in this thread:
http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2008-August/051220.html

I personally think we can remove it from CFLAGS in our case.

Dňa 12.12.2010 22:08, Andriy Gapon  wrote / napísal(a):
> on 12/12/2010 22:52 Andriy Gapon said the following:
>> on 12/12/2010 22:45 Kostik Belousov said the following:
>>> On Sun, Dec 12, 2010 at 10:40:12PM +0200, Andriy Gapon wrote:
>>>> To get around that issue _on Linux_, ffmpeg folks have put explicit
>>>> _SVID_SOURCE definition right into the libswscale/utils.c file:
>>>> #define _SVID_SOURCE //needed for MAP_ANONYMOUS
>>>>
>>>> For much the same reason we need to add the following for FreeBSD (as
>>>> hackish as it is): #define __BSD_VISIBLE 1
>>>>
>>>> With that addition the code buffer is allocated properly and the code
>>>> in it can be executed.
>>> Applications should never define the symbols from reserved namespace,
>>> in this case __BSD_VISIBLE. Right solution is to not define _POSIX_SOURCE.
>> i agree with you, but I don't know why the ffmpeg folks decided to use
>> _POSIX_C_SOURCE=200112 in the first place and what could break without it.
>>
> Actually the port seems to compile and work without any problems if I remove
> _POSIX_C_SOURCE definition in two places in configure.
>


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