[FFmpeg-devel] [PATCH] avformat/internal: Don't auto-include os_support.h

[Andreas Rheinhardt]

Martin Storsjö:
> On Thu, 31 Aug 2023, Andreas Rheinhardt wrote:
> 
>> It includes various Windows-specific headers when compiling
>> for Windows and these sometimes cause issues: E.g. winbase.h
>> defines IGNORE, which clashes with a macro used in the Matroska
>> muxer (since 884653ee5be03ed38db957c14fad51b300611c8c) and demuxer.
>>
>> This header provides fallback defines for various stuff that is
>> mostly not used directly by (de)muxers at all:
>> mkdir, rename, rmdir, unlink, access, poll, pollfd, nfds_t,
>> closesocket, socklen_t, fstat, stat, lseek, SHUT_(RD|WR|RDWR)
>> and various POLL* constants.
>>
>> Ergo fix this issue by not auto-including this header in lots
>> of places via an inclusion in internal.h and instead include
>> it everywhere where the above stuff is used (most of these
>> translation units already included os_support.h).
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
>> ---
>> libavformat/img2dec.c  | 1 +
>> libavformat/internal.h | 1 -
>> libavformat/rtsp.h     | 1 +
>> libavformat/utils.c    | 1 +
>> 4 files changed, 3 insertions(+), 1 deletion(-)
> 
> Ok with me, if you did a reasonable effort to check that this covers all
> the cases of the redirected functions. Spreading those includes
> everywhere isn't very nice indeed.
> 

I used
'\b(mkdir|rename|rmdir|unlink|access|poll|pollfd|nfds_t|closesocket|socklen_t|fstat|stat|lseek|SHUT_(RD|WR|RDWR)|POLL(IN|OUT|RDNORM|WRNORM|RDBAND|WRBAND|PRI|ERR|HUP|NVAL))\b'

(Also note that internal.h is not included everywhere.)

> This increases the risk of accidentally adding new uses of these
> functions without picking up the redirects, but I guess that's manageable.
> 

It also reduces the risk of accidentally causing macro conflicts like
with IGNORE.

- Andreas