[Slackbuilds-users] OpenCV SlackBuild bug - Was: ffmpeg does not compile with opencv 3.4.1

[Ythogtha]

> Thanks all for spotting the problem. I've just pushed a fix for it.
> 
> While working through this myself, I noticed that the requirement for
> python3 to generate a python3 binding no longer works unless numpy3 is
> also installed at build time. Since numpy3 requires python3, I've
> replaced the requirement for python3 with numpy3.
> 
> Back to the original problem of building ffmpeg with opencv support, I
> haven't been able to compile that successfully. The configure phase
> finds opencv OK but compilation fails with:
> 
> In file included from /usr/include/opencv2/core/types_c.h:59:0,
>                  from /usr/include/opencv2/core/core_c.h:48,
>                  from libavfilter/vf_libopencv.c:28:
> /usr/include/opencv2/core/cvdef.h:485:1: error: unknown type name
> 'namespace'
>  namespace cv {
>  ^
> /usr/include/opencv2/core/cvdef.h:485:14: error: expected '=', ',', ';',
> 'asm' or '__attribute__' before '{' token
>  namespace cv {
>               ^
> common.mak:60: recipe for target 'libavfilter/vf_libopencv.o' failed
> make: *** [libavfilter/vf_libopencv.o] Error 1
> 
> 
> It's not something I want to spend a lot of time trying to fix - for my
> own use I have the dependency the other way around by building opencv
> with ffmpeg support. However if anyone can propose a fix, I'm happy (and
> grateful) to include it in the SlackBuild.
> 
> chris

Hi!

	I just went back into this, used your updated build for OpenCV and
failed to compile ffmpeg.
Then I found this :
https://github.com/opencv/opencv/issues/10963
	So I modified the file /usr/include/opencv2/core/cvdef.h according to
what's said there.
And well, it works fine.
ffmpeg compiles and runs perfectly.

	So maybe including a patch to OpenCV since this seems to affect other
softwares, like VLC apparently ?
Your call Chris :)

-- 
Arnaud <yth at ythogtha.org>