clang and openmp in Mac OS X

note.md

Refer to https://clang-omp.github.io/ .

We need to install something:

brew install libiomp
brew install clang-omp

Then we need to set the environment:

export C_INCLUDE_PATH=/usr/local/Cellar/libiomp/20150701/include/libiomp:$C_INCLUDE_PATH
export CPLUS_INCLUDE_PATH=/usr/local/Cellar/libiomp/20150701/include/libiomp:$CPLUS_INCLUDE_PATH
export LIBRARY_PATH=/usr/local/Cellar/libiomp/20150701/lib:$LIBRARY_PATH

We create a file for testing:

/* hello.c */
#include <omp.h>
#include <stdio.h>
int main() {
    #pragma omp parallel
    printf("Hello from thread %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads());
}

Then compile it using clang-omp or clang-omp++:

clang-omp -fopenmp hello.c -o hello
./hello