[Slackbuilds-users] opencv-legacy issue

[Tim Dickson]

On 10/03/2019 07:32, Christoph Willing wrote:
> 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
>
my appologies, when I tested it last, it was from a command prompt so I 
forgot to add the OPENCV=yes WAYLAND=yes before calling the build script.
I too am getting it complaining about c++11 for opencv despite it being 
added to the CXXFLAGS in configure, and thus in the makefile. It may be 
that opencv is being called as c instead of c++ but I haven't managed to 
find out more yet.
regards, Tims