多线程发信号的问题

ruifengzhangyi

一般是用pthread_cond_signal pthread_cond_wait
也有用sem系列，请问有什么区别。是不是前者封装了后者。

J_O_H_N

The pthread_cond_signal() function shall unblock at least one of the threads that are blocked on the specified condition variable cond (if any threads are blocked on cond).

If more than one thread is blocked on a condition variable, the scheduling policy shall determine the order in which threads are unblocked. When each thread unblocked as a result of a pthread_cond_broadcast() or pthread_cond_signal() returns from its call to pthread_cond_wait() or pthread_cond_timedwait(), the thread shall own the mutex with which it called pthread_cond_wait() or pthread_cond_timedwait(). The thread(s) that are unblocked shall contend for the mutex according to the scheduling policy (if applicable), and as if each had called pthread_mutex_lock().

JohnBull

你所说的一切跟信号半毛钱关系都没有...

chenzhanyiczy

用途不同，实现方法也有所不同

zzyong08

pthread_cond_signal pthread_cond_wait，这两个用过，主要用来实现，生产者-消费者模型。生产者产生任务后，调用pthread_cond_signal通知消费者。消费者消费完，调用pthread_cond_wait等待新的任务。肯定还有别的用处，但都是实现线程同步的。

sem系列的函数，没经验。

cskyrain

不是前者封装了后者，是后者封装了前者。{:3_182:}

ruifengzhangyi

跟信号半毛钱没有，为何函数里有个signal单词呢？