pthread

函数pthread_cond_wait主要就是用于阻塞线程的，它有两个参数；第一个是一个指向条件变量的指针，第二个是一个锁定了的互斥量。

The function primarily used for this is pthread_cond_wait . It takes two arguments; the first is a pointer to a condition variable, and the second is a locked mutex.

This function is similar to pthread_cond_wait, except that the third argument is the absolute time value until which the reader thread is willing to wait before it gives up.