How does the SECTIONS directive in OpenMP distribute work?

Question

In OpenMP when using omp sections, will the threads be distributed to the blocks inside the sections, or will each thread be assigned to each sections?

Answer 1

It may be helpful to add more information to the output line and to add more sections (if you have the thread-count)

#pragma omp parallel sections
{
    #pragma omp section
    {
        printf ("section 1 id = %d, \n", omp_get_thread_num()); 
    }
    #pragma omp section
    {
        printf ("section 2 id = %d, \n", omp_get_thread_num());
    }
    #pragma omp section
    {
        printf ("section 3 id = %d, \n", omp_get_thread_num());
    }
}

Then you may get more interesting output like this:

section 1 id = 4,
section 3 id = 3,
section 2 id = 1,

which shows how the sections may be executed in any order, by any available thread.