[FFmpeg-devel] out tree build : possible config.h conflict

[matthieu castet]

Hi,

matthieu castet wrote:
> Hi,
> 
> if you build ffmpeg in tree and then latter you decide to build out of 
> tree you can have unexpected behavior :
> - there will be a config.h at the base of the source directory (from the 
> in tree build)
> - there will be a config.h at the base of the out of tree directory.
> 
> 
> And when building source at the base of the source directory, the bad 
> config.h will be taken, because the compiler will search first in the 
> source file directory.
> 
> This can be easily showed by putting a #error in the config.h of source 
> directory and #warning of build directory [1]
> 
> 
> The build system shouldn't allow out tree build in config.h is present 
> in source directory or it should find a way to not include it.
> 
> 
> Matthieu
> 
> [1]
> In file included from /home/mat/appli/ffmpeg/cmdutils.c:31:
> /home/mat/appli/ffmpeg/config.h:1:2: error: #error bad config
> In file included from /home/mat/appli/ffmpeg/libavutil/common.h:282,
>                   from /home/mat/appli/ffmpeg/libavutil/avutil.h:56,
>                   from /home/mat/appli/ffmpeg/libavcodec/avcodec.h:30,
>                   from /home/mat/appli/ffmpeg/libavformat/avformat.h:45,
>                   from /home/mat/appli/ffmpeg/cmdutils.c:32:
> ./config.h:1:2: warning: #warning good config
> In file included from /home/mat/appli/ffmpeg/libavutil/internal.h:37,
>                   from /home/mat/appli/ffmpeg/libavutil/common.h:283,
>                   from /home/mat/appli/ffmpeg/libavutil/avutil.h:56,
>                   from /home/mat/appli/ffmpeg/libavcodec/avcodec.h:30,
>                   from /home/mat/appli/ffmpeg/libavformat/avformat.h:45,
>                   from /home/mat/appli/ffmpeg/cmdutils.c:32:
> ./config.h:1:2: warning: #warning good config
> In file included from /home/mat/appli/ffmpeg/libavutil/timer.h:29,
>                   from /home/mat/appli/ffmpeg/libavutil/internal.h:40,
>                   from /home/mat/appli/ffmpeg/libavutil/common.h:283,
>                   from /home/mat/appli/ffmpeg/libavutil/avutil.h:56,
>                   from /home/mat/appli/ffmpeg/libavcodec/avcodec.h:30,
>                   from /home/mat/appli/ffmpeg/libavformat/avformat.h:45,
>                   from /home/mat/appli/ffmpeg/cmdutils.c:32:
> ./config.h:1:2: warning: #warning good config
> In file included from /home/mat/appli/ffmpeg/libavformat/network.h:24,
>                   from /home/mat/appli/ffmpeg/cmdutils.c:42:
> ./config.h:1:2: warning: #warning good config
> 

No comment on that ?

This behaviour is annoying. Is a patch doing like the Linux kernel 
(shouldn't allow out tree build if config.h is present) will be accepted ?

Matthieu