How do i solve this undefined reference?

/usr/local/include/opencv2/core/mat.hpp:367: undefined reference to cv::Mat::deallocate()' CMakeFiles/example6.dir/src/example6.cpp.o: In functioncv::Mat::release()':
/usr/local/include/opencv2/core/mat.hpp:367: undefined reference to cv::Mat::deallocate()' CMakeFiles/example6.dir/src/example6.cpp.o: In function~Mat':
/usr/local/include/opencv2/core/mat.hpp:278: undefined reference to cv::fastFree(void*)' CMakeFiles/example6.dir/src/example6.cpp.o: In functioncv::Mat::release()':
/usr/local/include/opencv2/core/mat.hpp:367: undefined reference to cv::Mat::deallocate()' CMakeFiles/example6.dir/src/example6.cpp.o: In functioncv::Mat::~Mat()':
/usr/local/include/opencv2/core/mat.hpp:278: undefined reference to cv::fastFree(void*)' CMakeFiles/example6.dir/src/example6.cpp.o: In function~Mat':
/usr/local/include/opencv2/core/mat.hpp:278: undefined reference to cv::fastFree(void*)' /usr/local/include/opencv2/core/mat.hpp:367: undefined reference tocv::Mat::deallocate()'
/usr/local/include/opencv2/core/mat.hpp:278: undefined reference to cv::fastFree(void*)' /usr/local/include/opencv2/core/mat.hpp:367: undefined reference tocv::Mat::deallocate()'
CMakeFiles/example6.dir/src/example6.cpp.o: In function main': /home/raoul/dev/rosbook/chapter3_tutorials/src/example6.cpp:19: undefined reference tocv::VideoCapture::VideoCapture(int)'
/home/dev/rosbook/chapter3_tutorials/src/example6.cpp:20: undefined reference to
/home/dev/rosbook/chapter3_tutorials/src/example6.cpp:19: undefined reference to `cv::VideoCapture::~VideoCapture()'

I am using Opencv 2.9?

[efernandez]

I think you need to add a find_library for OpenCV and then add target_link_libraries for each executable affected, linking against ${OpenCV_LIBRARIES}.

Something like that should work. However, with rosbuild this usually doesn't happen. Which branch are you using? master?

[Ichini24]

Hello. I have a similar problem. Did u find an issue and can u share it with me?