flush (OpenMP)

Specifies that all threads have the same view of memory for all shared objects.

#pragma omp flush [(var)]

Remarks

where,

• var (optional)
  A comma-separated list of variables that represent objects you want to synchronize. If var is not specified, all memory is flushed.

Remarks

The flush directive supports no OpenMP clauses.

For more information, see 2.6.5 flush Directive.

Example

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

void read(int *data) {
   printf_s("read data\n");
   *data = 1;
}

void process(int *data) {
   printf_s("process data\n");
   (*data)++;
}

int main() {
   int data;
   int flag;

   flag = 0;

   #pragma omp parallel sections num_threads(2)
   {
      #pragma omp section
      {
         printf_s("Thread %d: ", omp_get_thread_num( ));
         read(&data);
         #pragma omp flush(data)
         flag = 1;
         #pragma omp flush(flag)
         // Do more work.
      }

      #pragma omp section 
      {
         while (!flag) {
            #pragma omp flush(flag)
         }
         #pragma omp flush(data)
       
         printf_s("Thread %d: ", omp_get_thread_num( ));
         process(&data);
         printf_s("data = %d\n", data);
      }
   }
}

Thread 0: read data
Thread 1: process data
data = 2

See Also

Reference

OpenMP Directives