drd/tests/omp_printf.c

   1 /* Simple OpenMP test program that calls printf() from a parallel section. */
   2
   3 #include <assert.h>  // assert()
   4 #include <omp.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>  // atoi()
   7 #include <unistd.h>  // getopt()
   8
   9 static void usage(const char* const exe)
  10 {
  11   fprintf(stderr,
  12           "Usage: %s [-h] [-i <n>] [-q] [-t<n>]\n"
  13           "-h: display this information.\n"
  14           "-i <n>: number of loop iterations.\n"
  15           "-q: quiet mode -- do not print computed error.\n"
  16           "-t <n>: number of OMP threads.\n",
  17           exe);
  18 }
  19
  20 int main(int argc, char** argv)
  21 {
  22   int i;
  23   int optchar;
  24   int silent = 0;
  25   int tid;
  26   int num_iterations = 2;
  27   int num_threads = 2;
  28
  29   while ((optchar = getopt(argc, argv, "hi:qt:")) != EOF)
  30   {
  31     switch (optchar)
  32     {
  33     case 'h': usage(argv[0]); return 1;
  34     case 'i': num_iterations = atoi(optarg); break;
  35     case 'q': silent = 1; break;
  36     case 't': num_threads = atoi(optarg); break;
  37     default:
  38       return 1;
  39     }
  40   }
  41
  42   /*
  43    * Not the most user-friendly way of error checking, but still better than
  44    * no error checking.
  45    */
  46   assert(num_iterations > 0);
  47   assert(num_threads > 0);
  48
  49   omp_set_num_threads(num_threads);
  50   omp_set_dynamic(0);
  51
  52 #pragma omp parallel for private(tid)
  53   for (i = 0; i < num_iterations; i++)
  54   {
  55     tid = omp_get_thread_num();
  56     if (! silent)
  57     {
  58       fprintf(stderr,
  59               "iteration %d; thread number = %d; number of threads = %d\n",
  60               i, tid, omp_get_num_threads());
  61     }
  62     else
  63     {
  64       fprintf(stderr, "%s", "");
  65     }
  66   }
  67
  68   fprintf(stderr, "Finished.\n");
  69
  70   return 0;
  71 }