#include <stdio.h>
#include <omp.h>

// Completely pointless function, just for doing something.
int do_something()
{
#ifdef _OPENMP
omp_lock_t lock;
omp_init_lock(&lock);
const unsigned NC = omp_get_max_threads();

  fprintf(stderr, "Running %d iterations.\n", 10*NC);
  
#pragma omp parallel shared(lock)
{
  #pragma omp for 
  for (int k = 0; k < 10*NC; ++k) {
    omp_set_lock(&lock);           // ...CRITICAL STARTS
    fprintf(stderr, "Iteration: %d\n", k);  
    omp_unset_lock(&lock);         // ...CRITICAL ENDS
    }
}
#endif // _OPENMP

  return 0;
}
int main()
{
#ifdef _OPENMP
  fprintf(stderr, "Using OpenMP!\n");
  fprintf(stderr, "\t---> Maximum number of threads available: %d\n", omp_get_max_threads());
  fprintf(stderr, "\t---> Number of processing units: %d\n", omp_get_num_procs());
  omp_set_dynamic(1);
  fprintf(stderr, "\t---> Using %s thread allocation strategy.\n",
		(omp_get_dynamic() ? "dynamic" : "static"));
#else
  fprintf(stderr, "No OpenMP.\n");
#endif
  fflush(NULL);

  do_something();
  
  return 0;
}