how to build opencv for python3 when both python2 and python3 are installed

Question

I was trying to build opencv for python3. However, cmake always sets python build option to be python2.7.11 even after I manually specified include and lib option for python

Answer 1

I was struggling with this one for some hours and the answers mentioned above didn't solve the problem straightaway.

Adding to Ivan's answer, I had to include these flags in cmake to make this work:

-D BUILD_NEW_PYTHON_SUPPORT=ON \
-D BUILD_opencv_python3=ON \
-D HAVE_opencv_python3=ON \
-D PYTHON_DEFAULT_EXECUTABLE= 

I leave that here, so it is maybe useful for someone else in the future.