/* compile with -fopenmp */
#include <stdio.h>

static void
sum(long i, long j, long *out) {
  if (i>j)
    return;
  if (i==j) {
    (*out)++;
  } else {
    long m=(i+j)/2;
#pragma omp task
    sum(i,m,out);
    sum(m+1,j, out);
#pragma omp taskwait
  }
}

int main(int argc, char** argv){

  long x = 0;

#pragma omp parallel
  {  
    sum(1,10000, &x);
  }

  printf("x = %ld\n", x);
}