when enabling that flag with kernel-2.6.38, opencv fails compilation when building createsamples bin, that is due to highgui.so is missing cvCreateCameraCapture_V4L which can be found in either OpenCv/modules/highgui/src/cap_v4l.cpp or OpenCv/modules/highgui/src/cap_libv4l.cpp which are added only if v4l flag is enabled and both linux/videodev.h and linux/videodev2.h are found.
disabling the flags causes opencv to compiles well.
Steps to Reproduce:
1. emerge kernel 2.6.38
2. emerge opencv with open v4l flag
you get this:
[ 79%] Built target _highgui
Scanning dependencies of target createsamples
[ 79%] Building CXX object apps/haartraining/CMakeFiles/createsamples.dir/createsamples.o
Linking CXX executable ../../bin/opencv_createsamples
[ 79%] Building CXX object src/cvaux/CMakeFiles/cvaux.dir/vs/blobtrackanalysishist.o
cc1plus: warning: /var/tmp/portage/media-libs/opencv-2.1.0/work/opencv-2.1.0_build/src/cvaux/_cvaux.h.gch/cvaux_Gentoo.gch: not used because `NDEBUG' is defined
../../lib/libhighgui.so.2.1.0: undefined reference to `cvCreateCameraCapture_V4L(int)'
collect2: ld returned 1 exit status
make: *** [bin/opencv_createsamples] Error 1
make: *** [apps/haartraining/CMakeFiles/createsamples.dir/all] Error 2
make: *** Waiting for unfinished jobs....
opencv compiles well.
relevant lines are:
Confirming bug on Gentoo, kernel 126.96.36.199 x86
*** Bug 363279 has been marked as a duplicate of this bug. ***
This bug was on the kernel 3.6.36-r5
*** Bug 363393 has been marked as a duplicate of this bug. ***
What does the arch team have to do with this?
I'm completed building! I've completed "python-update" and removed "gstreamer v41" in use-flags.
I confirm that disabling the "gstreamer" and "v4l" USE flags helps here. I have managed to build it with USE="deprecated ffmpeg gtk jpeg jpeg2k octave png python sse sse2 sse3 tiff -debug -examples -gstreamer -ieee1394 -ipp -ssse3 -test -v4l -xine".
Fixed in 2.2.0 in kde overlay. Will be moved to main tree soon.