使用清除的指示詞,沒有清單的 A.14
下列範例 (如區段 2.6.5 20 頁面上) 區分出受影響的共用的物件flush指示詞不會受到影響的共用物件從任何清單:
範例
程式碼
// omp_flush_without_list.c
#include <omp.h>
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()
{
}