A Real Condition For A Condition Variable (Cont.)

On the waiting side:

 /* lock the mutex. */
 pthread_mutex_lock(&mutex);

 while (!q_size(q) > 0) {
   pthread_cond_wait(&cond, &mutex);
 }

 /* get first element off the queue. */
 e = q->get_first();

 /* unlock the mutex. */
 pthread_mutex_unlock(&mutex);

 /* do something with the element */
 handle_element(e);