SpresenseでNuttXのpthreadsを使用しマルチスレッドを学ぶ #6　〜バリアで同期して各スレッドの処理の足並みを揃える〜

// 初期化完了同期用バリア変数
pthread_barrier_t initialization_completion_barrier;

#define THREAD_NUM   (3)  // スレッドの数

int main(int argc, FAR char *argv[])
{

  if (pthread_barrier_init(&initialization_completion_barrier, NULL, THREAD_NUM) != 0) {
      printf("Error; pthread_barrier_init.\n");
      exit(1);
  }
  
}

void* thread_func(void* arg) {
  int thread_index = (uint32_t)arg;
  int ret;
#if 1
  unsigned int initialize_time = 3 * (thread_index + 1);
#else
  unsigned int initialize_time;

  if (thread_index == 0) {
    initialize_time = 9;    
  } else if (thread_index == 1) {
    initialize_time = 6;    
  } else {
    initialize_time = 3;
  }
#endif

  printf("thread index[%d] start.initialize_time = %d(sec).\n", thread_index, initialize_time);

  sleep(initialize_time);

  printf("thread index[%d] initialize end.\n", thread_index);

  ret = pthread_barrier_wait(&initialization_completion_barrier);
  if (!(ret == 0 || ret == PTHREAD_BARRIER_SERIAL_THREAD)) {
    printf("Error; thread index[%d] pthread_barrier_wait ret = %d.\n", thread_index, ret);
    exit(1);
  }

  printf("thread index[%d] barrier exit.ret = %d.\n", thread_index, ret);

  return (void*)thread_index;
}

int main(int argc, FAR char *argv[])
{

  if (pthread_barrier_destroy(&initialization_completion_barrier) != 0) {
      printf("Error; pthread_barrier_destroy.\n");
      exit(1);
  }

  printf("Bye.\n");

  return 0;
}