cond_var2.cpp

#include <iostream>
#include <deque>
#include <thread>
#include <mutex>
#include <condition_variable>

std::deque<int> q;						//双端队列标准容器全局变量
std::mutex mu;							//互斥锁全局变量
std::condition_variable cond;           //全局条件变量

//生产者，往队列放入数据
void function_1() {
    int count = 10;
    while (count > 0) {
        std::unique_lock<std::mutex> locker(mu);
        q.push_front(count);			//数据入队锁保护
        locker.unlock();
        cond.notify_one();              // 向一个等待线程发出“条件已满足”的通知
        std::this_thread::sleep_for(std::chrono::seconds(1));		//延时1秒
        count--;
    }
}
//消费者，从队列提取数据
void function_2() {
    int data = 0;
    while ( data != 1) {
        std::unique_lock<std::mutex> locker(mu);
        
        //while(q.empty())        //判断队列是否为空
        //    cond.wait(locker); // 解锁互斥量并陷入休眠以等待通知被唤醒，被唤醒后加锁以保护共享数据

        cond.wait(locker, [](){ return !q.empty();});   //如果条件变量被唤醒，检查队列非空条件是否为真，为真则直接返回，为假则继续等待

        data = q.back();
        q.pop_back();			//数据出队锁保护
        locker.unlock();
        std::cout << "t2 got a value from t1: " << data << std::endl;
    }
}

int main() 
{
    std::thread t1(function_1);
    std::thread t2(function_2);
    t1.join();
    t2.join();

    getchar();
    return 0;
}