gcc/libgomp/testsuite/libgomp.c/lock-1.c

#include <omp.h>
#include <stdlib.h>

int
main (void)
{
  int l = 0;
  omp_nest_lock_t lock;
  omp_init_nest_lock (&lock);
  if (omp_test_nest_lock (&lock) != 1)
    abort ();
  if (omp_test_nest_lock (&lock) != 2)
    abort ();
#pragma omp parallel if (0) reduction (+:l)
  {
    /* In OpenMP 2.5 this was supposed to return 3,
       but in OpenMP 3.0 the parallel region has a different
       task and omp_*_lock_t are owned by tasks, not by threads.  */
    if (omp_test_nest_lock (&lock) != 0)
      l++;
  }
  if (l)
    abort ();
  if (omp_test_nest_lock (&lock) != 3)
    abort ();
  omp_unset_nest_lock (&lock);
  omp_unset_nest_lock (&lock);
  omp_unset_nest_lock (&lock);
  omp_destroy_nest_lock (&lock);
  return 0;
}