[Slackbuilds-users] opencv-legacy issue

[Christoph Willing]

On 8/3/19 10:10 pm, Tim Dickson via SlackBuilds-users wrote:
> I think the problem is that opencv version 4 reports itself as opencv4
> to pkg-config whereas opencv-legacy reports itself as opencv
> copying /usr/lib64/pkgconfig/opencv4 to /usr/lib64/pkgconfig/opencv gets
> further and bails at
> 
> /usr/include/opencv4/opencv2/core/cvdef.h:109:47: warning: "__cplusplus"
> is not defined [-Wundef]
>  #  if (defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L)
>                                                ^
> In file included from /usr/include/opencv4/opencv2/core/types_c.h:82:0,
>                  from /usr/include/opencv4/opencv2/core/core_c.h:48,
>                  from video_filter/opencv_wrapper.c:42:
> /usr/include/opencv4/opencv2/core/cvdef.h:647:7: warning: "__cplusplus"
> is not defined [-Wundef]
>  #  if __cplusplus >= 201103L || (defined(_MSC_VER) && _MSC_VER >= 1800)
>        ^
> /usr/include/opencv4/opencv2/core/cvdef.h:656:4: error: #error "OpenCV
> 4.x+ requires enabled C++11 support"
>  #  error "OpenCV 4.x+ requires enabled C++11 support"
>     ^
> /usr/include/opencv4/opencv2/core/cvdef.h:661:17: fatal error: array: No
> such file or directory
> compilation terminated.
> Makefile:21527: recipe for target
> 'video_filter/libopencv_wrapper_plugin_la-opencv_wrapper.lo' failed
> make[4]: ***
> [video_filter/libopencv_wrapper_plugin_la-opencv_wrapper.lo] Error 1
> make[4]: Leaving directory '/tmp/SBo/vlc-3.0.6/modules'
> Makefile:26254: recipe for target 'all-recursive' failed
> make[3]: *** [all-recursive] Error 1
> make[3]: Leaving directory '/tmp/SBo/vlc-3.0.6/modules'
> Makefile:11314: recipe for target 'all' failed
> make[2]: *** [all] Error 2
> make[2]: Leaving directory '/tmp/SBo/vlc-3.0.6/modules'
> Makefile:1539: recipe for target 'all-recursive' failed
> make[1]: *** [all-recursive] Error 1
> make[1]: Leaving directory '/tmp/SBo/vlc-3.0.6'
> Makefile:1424: recipe for target 'all' failed
> make: *** [all] Error 2
> 
> To fix that error I had to modify the slackbuild, specifically the line
> calling ./configure see below
> CXXFLAGS="$SLKCFLAGS -std=c++11" \
> 
Hi Tim,

I thought I'd try this out but even with the -std=c++11 added to
CXXFLAGS, I still see the same error about missing c++11 suport. Do you
recall doing anything else to help the compilation along?

chris