如何“停止”等待条件变量的分离线程?

尝试以下代码段:set bool member variable discard_ 到 true 要避免执行计划的流程执行,请执行以下操作:

std::thread([&](){
   std::lock_guard<std::mutex> lock(mutex_);
   cv.wait(lock,[](){ return normal_predicate_here || discard_ ;});
   if(discard_) return;
   // execute scheduled process
}).detach();

使另一个线程协同终止非分离线程使干净地终止变得更容易,这样就不会过早地破坏另一个线程访问的状态:

struct OtherThread {
    std::mutex m_;
    std::condition_variable c_;
    bool stop_ = false;
    std::thread t_;

    void thread_function() {
        for(;;) {
            std::unique_lock<std::mutex> l(m_);
            while(!stop_ /* || a-message-received */)
                c_.wait(l);
            if(stop_)
                return;

            // Process a message.
            // ...
            // Continue waiting for messages or stop.
        }
    }

    ~OtherThread() {
        this->stop();
    }

    void stop() {
        {
            std::unique_lock<std::mutex> l(m_);
            if(stop_)
                return;
            stop_ = true;
        }
        c_.notify_one();
        t_.join(); // Wait till the thread exited, so that this object can be destroyed.
    }
};