CMake cannot find OpenMP

Question

I am trying to compile with OpenMP. My CMakeLists.txt contains the line

find_package(OpenMP REQUIRED)

and CMake errors out with

Answer 1

OpenMp is not a package, if it's supported, it comes as a part of the your compiler. Try setting CMAKE_C_FLAGS or CMAKE_CXX_FLAGS accordingly. e.g:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fopenmp") activates OpenMP for compiling C sources when gcc is used. For other compilers, you should first detect the compiler and then add appropriate flags