/* Simple OpenMP test program that calls printf() from a parallel section. */
+#include <assert.h> // assert()
#include <omp.h>
#include <stdio.h>
+#include <stdlib.h> // atoi()
#include <unistd.h> // getopt()
static void usage(const char* const exe)
{
- printf("Usage: %s [-h] [-q] [-r] [-t<n>] <m>\n"
- "-h: display this information.\n"
- "-q: quiet mode -- do not print computed error.\n",
- exe);
+ fprintf(stderr,
+ "Usage: %s [-h] [-i <n>] [-q] [-t<n>]\n"
+ "-h: display this information.\n"
+ "-i <n>: number of loop iterations.\n"
+ "-q: quiet mode -- do not print computed error.\n"
+ "-t <n>: number of OMP threads.\n",
+ exe);
}
int main(int argc, char** argv)
int optchar;
int silent = 0;
int tid;
+ int num_iterations = 2;
+ int num_threads = 2;
- while ((optchar = getopt(argc, argv, "hq")) != EOF)
+ while ((optchar = getopt(argc, argv, "hi:qt:")) != EOF)
{
switch (optchar)
{
case 'h': usage(argv[0]); return 1;
+ case 'i': num_iterations = atoi(optarg); break;
case 'q': silent = 1; break;
+ case 't': num_threads = atoi(optarg); break;
default:
return 1;
}
}
-#pragma omp parallel private(tid)
- for (i = 0; i < 2; i++)
+ /*
+ * Not the most user-friendly way of error checking, but still better than
+ * no error checking.
+ */
+ assert(num_iterations > 0);
+ assert(num_threads > 0);
+
+ omp_set_num_threads(num_threads);
+ omp_set_dynamic(0);
+
+#pragma omp parallel for private(tid)
+ for (i = 0; i < num_iterations; i++)
{
tid = omp_get_thread_num();
if (! silent)
{
- printf("omp_get_thread_num() = %d/%d\n", tid, omp_get_num_threads());
+ fprintf(stderr,
+ "iteration %d; thread number = %d; number of threads = %d\n",
+ i, tid, omp_get_num_threads());
}
else
{
- printf("%s", "");
+ fprintf(stderr, "%s", "");
}
}