omp_bug2.c

/******************************************************************************
 * FILE: omp_bug2.c
 * DESCRIPTION:
 *   Another OpenMP program with a bug.
 * AUTHOR: Blaise Barney 
 * LAST REVISED: 04/06/05 
 ******************************************************************************/
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char *argv[]) 
{
  int nthreads, i, tid;
  float total;

  /*** Spawn parallel region ***/
#pragma omp parallel 
  {
    /* Obtain thread number */
    tid = omp_get_thread_num();
    /* Only master thread does this */
    if (tid == 0) {
      nthreads = omp_get_num_threads();
      printf("Number of threads = %d\n", nthreads);
    }
    printf("Thread %d is starting...\n",tid);

#pragma omp barrier

    /* do some work */
    total = 0.0;
#pragma omp for schedule(dynamic,10)
    for (i=0; i<1000000; i++) 
      total = total + i*1.0;

    printf ("Thread %d is done! Total= %e\n",tid,total);

  } /*** End of parallel region ***/
}