Listing 3: The Writer Thread
  // The queue
  queue<int> power2Queue;

  // Mutex and condition variable for controlling access to the queue
  mutex_t queueReady;
  cond_t signalQueueReady;
  
  // Initialize the mutex and condition variable
  mutex_init(&queueReady, USYNC_THREAD, NULL);
  cond_init(&signalQueueReady, USYNC_THREAD, NULL);
  ...
  // Lock the queue and add some data
  mutex_lock(&queueReady);
  power2Queue.push(999);
  
  // Inform the reader that some data is available
  cond_signal(&signalQueueReady);
  mutex_unlock(&queueReady);