single

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

#pragma omp single [clauses] 
{
   code_block  
}

Parameters

• clause (optional)
  Zero or more clauses. See the Remarks section for a list of the clauses supported by single.

Remarks

The single directive supports the following OpenMP clauses:

• copyprivate

• firstprivate

• nowait

• private (OpenMP)

The master directive lets you specify that a section of code should be executed only on the master thread.

For more information, see 2.4.3 single Construct.

Example

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

int main() {
   #pragma omp parallel num_threads(2)
   {
      #pragma omp single
      // Only a single thread can read the input.
      printf_s("read input\n");
      
      // Multiple threads in the team compute the results.
      printf_s("compute results\n");

      #pragma omp single
      // Only a single thread can write the output.
      printf_s("write output\n");
    }
}

read input compute results compute results write output

See Also

Reference

OpenMP Directives