master

Specifies that only the master threadshould execute a section of the program.

#pragma omp master
{
      code_block
}

Заметки

The master directive supports no OpenMP clauses.

The single directive lets you specify that a section of code should be executed on a single thread, not necessarily the master thread.

For more information, see 2.6.1 master Construct.

Пример

// omp_master.cpp
// compile with: /openmp 
#include <omp.h>
#include <stdio.h>

int main( ) 
{
    int a[5], i;

    #pragma omp parallel
    {
        // Perform some computation.
        #pragma omp for
        for (i = 0; i < 5; i++)
            a[i] = i * i;

        // Print intermediate results.
        #pragma omp master
            for (i = 0; i < 5; i++)
                printf_s("a[%d] = %d\n", i, a[i]);
      
        // Wait.
        #pragma omp barrier

        // Continue with the computation.
        #pragma omp for
        for (i = 0; i < 5; i++)
            a[i] += i;
    }
}

a[0] = 0
a[1] = 1
a[2] = 4
a[3] = 9
a[4] = 16

См. также

Основные понятия

OpenMP Directives