1// RUN: %libomp-compile-and-run
2#include <stdio.h>
3#include "omp_testsuite.h"
4
5/*
6 * This test will hang if the nowait is not working properly.
7 *
8 * It relies on a thread skipping to the second for construct to
9 * release the threads in the first for construct.
10 *
11 * Also, we use static scheduling to guarantee that one
12 * thread will make it to the second for construct.
13 */
14volatile int release;
15volatile int count;
16
17void wait_for_release_then_increment(int rank)
18{
19 fprintf(stderr, format: "Thread nr %d enters first for construct"
20 " and waits.\n", rank);
21 while (release == 0);
22 #pragma omp atomic
23 count++;
24}
25
26void release_and_increment(int rank)
27{
28 fprintf(stderr, format: "Thread nr %d sets release to 1\n", rank);
29 release = 1;
30 #pragma omp atomic
31 count++;
32}
33
34int test_omp_for_nowait()
35{
36 release = 0;
37 count = 0;
38
39 #pragma omp parallel num_threads(4)
40 {
41 int rank;
42 int i;
43
44 rank = omp_get_thread_num();
45
46 #pragma omp for schedule(static) nowait
47 for (i = 0; i < 4; i++) {
48 if (i < 3)
49 wait_for_release_then_increment(rank);
50 else {
51 fprintf(stderr, format: "Thread nr %d enters first for and goes "
52 "immediately to the next for construct to release.\n", rank);
53 #pragma omp atomic
54 count++;
55 }
56 }
57
58 #pragma omp for schedule(static)
59 for (i = 0; i < 4; i++) {
60 release_and_increment(rank);
61 }
62 }
63 return (count==8);
64}
65
66int main()
67{
68 int i;
69 int num_failed=0;
70
71 for(i = 0; i < REPETITIONS; i++) {
72 if(!test_omp_for_nowait()) {
73 num_failed++;
74 }
75 }
76 return num_failed;
77}
78

source code of openmp/runtime/test/worksharing/for/omp_for_nowait.c