5. Conditions

pthread_cond_init(), pthread_cond_signal(), pthread_cond_wait()

  int pthread_cond_init(pthread_cond_t *restrict cond, const pthread_condattr_t *restrict attr);
  pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
  int pthread_cond_signal(pthread_cond_t *cond);
  int pthread_cond_wait(pthread_cond_t *restrict cond, pthread_mutex_t *restrict mutex);

Example:

  pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
  pthread_cond_t cond = PTHREAD_COND_INITIALIZER;

 // some thread, waiting:
  Pthread_mutex_lock(&lock);
    while (ready == 0) Pthread_cond_wait(&cond, &lock);
    // condition occurred and we have the lock here
    ... do stuff ...
  Pthread_mutex_unlock(&lock);

 // some other thread, signaling:
  Pthread_mutex_lock(&lock);
    ... do stuff ...
    ready = 1;
    Pthread_cond_signal(&cond);
  Pthread_mutex_unlock(&lock);