std :: condition_variable的notify_all()和notify_one()有什么区别? [英] What's the difference between notify_all() and notify_one() of std::condition_variable?

问题描述

当前，我正在C ++ 11中使用std::thread实现多线程项目.我使用std::condition_variable同步线程.详细地，一个使用者函数调用std::condition_variable的wait()成员函数来等待全局任务队列中的任务，另一个生产者函数生成任务并将其放入队列.但是我不知道std::condition_variable的notify_all()和notify_one()成员函数之间的区别.在生产者函数中应该使用哪个函数?谢谢！

Currently, I am implementing a multi-thread project using std::thread in C++11. I use std::condition_variable to synchronize threads. In detail, one consumer function calls wait() member function of std::condition_variable to wait for task from a global task queue, another producer function generates and puts tasks into the queue. But I do not know the difference between notify_all() and notify_one() member functions of std::condition_variable. Which function should I use in the producer function? Thanks!

推荐答案

例如，如果条件变量上有十个线程被阻塞，则notify_one()将仅解除阻塞一个线程，而notify_all()将对其全部解除阻塞.在您的情况下，您将要使用notify_one()，这样就不会唤醒没有任何工作在等待它们的线程.

If there are ten threads blocked on the condition variable, for example, notify_one() will unblock only one thread, while notify_all() will unblock them all. In your case, you'll want to use notify_one() so you don't wake up threads that don't have any work waiting for them.

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