Parallel Programming In C | Hello World!

Let us write a simple "Hello, World!" program where the text will be placed in the parallel region and will be printed several times by different threads.

We will use OpenMP C/C++ Application Program Interface (API)

C Program

#include <stdio.h>
#include <omp.h>

int main()
{
    #pragma omp parallel
    {
        printf("Hello, World! From  -> Thread %d.\n",omp_get_thread_num());
    }
    return 0;
}

Output

$ vim hello.c
$ gcc -fopenmp hello.c -o hello
$ ./hello
Hello, World! From  -> Thread 2.
Hello, World! From  -> Thread 3.
Hello, World! From  -> Thread 0.
Hello, World! From  -> Thread 1.

# of printf() may differ..