pthread库提供哪两种线程同步机制, 列出主要API。
一种是mutex
pthread_mutex_init()
pthread_mutex_lock()
pthread_mutex_trylock()
pthread_mutex_unlock()
pthread_mutex_destory()
一种是condition
pthread_cond_init
()
pthread_cond_signal
pthread_cond_broadcast
pthread_cond_wait