Unable to install open-cv in virtual env

Trying to install it using the below command

cmake -D WITH_CUDA=ON -D CUDA_ARCH_BIN=“5.3” -D CUDA_ARCH_PTX="" -D WITH_GSTREAMER=ON -D WITH_LIBV4L=ON -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF -D BUILD_EXAMPLES=ON -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_PYTHON_EXAMPLES=ON -D INSTALL_C_EXAMPLES=OFF -D OPENCV_EXTRA_MODULES_PATH=/home/nvidia/opencv_contrib-3.4.6/modules -D PYTHON3_EXECUTABLE=/home/nvidia/venv/bin/python PYTHON3_NUMPY_INCLUDE_DIRS=/home/nvidia/venv/lib/python3.6/site-packages/numpy/core/include/ BUILD_opencv_python3=yes -D PYTHON_PACKAGES_PATH=~/home/nvidia/venv/lib/python3.6/site-packages/ -D PYTHON_LIBRARY=/usr/lib/aarch64-linux-gnu/libpython3.6m.so …

I got the following error in CmakeError.log

Build output check failed:
Regex: ‘command line option .* is valid for .* but not for C++’
Output line: ‘cc1plus: warning: command line option ‘-Wmissing-prototypes’ is valid for C/ObjC but not for C++’
Compilation failed:
source file: ‘/opencv-3.4.6/build/CMakeFiles/CMakeTmp/src.cxx’

Not sure this is the cause of your issue, but you may try to add ‘-D’ before PYTHON3_NUMPY_INCLUDE_DIRS and before BUILD_opencv_python3.