libgomp/testsuite/libgomp.c/appendix-a/a.39.1.c

   1 /* { dg-do run } */
   2
   3 #include <stdio.h>
   4 #include <omp.h>
   5 void
   6 skip (int i)
   7 {
   8 }
   9
  10 void
  11 work (int i)
  12 {
  13 }
  14 int
  15 main ()
  16 {
  17   omp_lock_t lck;
  18   int id;
  19   omp_init_lock (&lck);
  20 #pragma omp parallel shared(lck) private(id)
  21   {
  22     id = omp_get_thread_num ();
  23     omp_set_lock (&lck);
  24     /* only one thread at a time can execute this printf */
  25     printf ("My thread id is %d.\n", id);
  26     omp_unset_lock (&lck);
  27     while (!omp_test_lock (&lck))
  28       {
  29         skip (id);              /* we do not yet have the lock,
  30                                    so we must do something else */
  31       }
  32     work (id);                  /* we now have the lock
  33                                    and can do the work */
  34     omp_unset_lock (&lck);
  35   }
  36   omp_destroy_lock (&lck);
  37   return 0;
  38 }