OpenMP-Examples/sources/Example_flush_nolist.1.c

/*
* @@name:	flush_nolist.1c
* @@type:	C
* @@compilable:	yes
* @@linkable:	yes
* @@expect:	success
*/
int x, *p = &x;

void f1(int *q)
{
  *q = 1;
  #pragma omp flush
  /* x, p, and *q are flushed */
  /* because they are shared and accessible */
  /* q is not flushed because it is not shared. */
}

void f2(int *q)
{
  #pragma omp barrier
  *q = 2;
  #pragma omp barrier

  /* a barrier implies a flush */
  /* x, p, and *q are flushed */
  /* because they are shared and accessible */
  /* q is not flushed because it is not shared. */
}

int g(int n)
{
  int i = 1, j, sum = 0;
  *p = 1;
  #pragma omp parallel reduction(+: sum) num_threads(10)
  {
    f1(&j);

    /* i, n and sum were not flushed */
    /* because they were not accessible in f1 */
    /* j was flushed because it was accessible */
    sum += j;

    f2(&j);

    /* i, n, and sum were not flushed */
    /* because they were not accessible in f2 */
    /* j was flushed because it was accessible */
    sum += i + j + *p + n;
  }
  return sum;
}

int main()
{
  int result = g(7);
  return result;
}