Enable OpenMP support in clang in Mac OS X (sierra & Mojave)

Question

I am using Mac OS X Sierra, and I found that clang (LLVM version 8.1.0 (clang-802.0.38)) does not support OpenMP: when I run clang -fopenmp program_name.c, I go

Answer 1

MacOS Mojave with CMake

1. Install LLVM with openmp and libomp with brew

    brew update
    brew install llvm libomp
   

2. add include directories and link directories in CMakeList.txt

    include_directories("/usr/local/include" "/usr/local/opt/llvm/include")
    link_directories("/usr/local/lib" "/usr/local/opt/llvm/lib")
   

3. run CMake with the new compilers

    cmake -DCMAKE_C_COMPILER="/usr/local/opt/llvm/bin/clang" -DCMAKE_CXX_COMPILER="/usr/local/opt/llvm/bin/clang++" ..
   

The clang version is 7.0.1 at time of writing