flush.c
975 Bytes
// RUN: %compile-run-and-check
#include <omp.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
int data, out, flag = 0;
#pragma omp target parallel num_threads(64) map(tofrom \
: out, flag) map(to \
: data)
{
if (omp_get_thread_num() == 0) {
/* Write to the data buffer that will be read by thread */
data = 42;
/* Flush data to thread 32 */
#pragma omp flush(data)
/* Set flag to release thread 32 */
#pragma omp atomic write
flag = 1;
} else if (omp_get_thread_num() == 32) {
/* Loop until we see the update to the flag */
int val;
do {
#pragma omp atomic read
val = flag;
} while (val < 1);
out = data;
#pragma omp flush(out)
}
}
// CHECK: out=42.
/* Value of out will be 42 */
printf("out=%d.\n", out);
return !(out == 42);
}