long num_processor_configured = sysconf (_SC_NPROCESSORS_CONF); /* list the number of processors configured */
 long num_processor_available;
 cpu_set_t mask;

  if (sched_getaffinity(0, sizeof(cpu_set_t), &mask) == 0) {
    num_processor_available = CPU_COUNT(&mask);
  } else {
    num_processor_available = sysconf(_SC_NPROCESSORS_ONLN);
  }

  printf("CPUs: %ld configured, %ld online\n", num_processor_configured, num_processor_available);