c++ thread, 模板类，锁的调用实例

#include<thread>
#include<condition_variable>
#include<mutex>
#include<queue>
#include<stdio.h>

template <class T>
class ThreadSafeQueue{
    public:
        void Insert(T value);
        void Popup(T &value);
        bool Empty() const;

    private:
        mutable std::mutex mut_;
        std::queue<T> que_;
        std::condition_variable cond_;
};

template <class T>
void ThreadSafeQueue<T>::Insert(T value){
    std::lock_guard<std::mutex> lk(mut_);
    que_.push(value);
    cond_.notify_one();
}

template <class T>
void ThreadSafeQueue<T>::Popup(T &value){
    std::unique_lock<std::mutex> lk(mut_);
    cond_.wait(lk, [this]{return !que_.empty();}); // 如果lamda表达式 [this]{return !que_.empty(); 返回 true, 也就是队列非空，则上锁，继续执行下面的语句；
    value = que_.front();                          // 如果lamda表达式返回False, 也就是队列为空，则解开锁，该线程进入wait，阻塞模式，等待被唤醒
    que_.pop();
}

template <class T>
bool ThreadSafeQueue<T>::Empty() const{
    std::lock_guard<std::mutex> lk(mut_);
    return que_.empty();
}

int main(){
    ThreadSafeQueue<int> q;
    int value=1;
    std::thread t2(&ThreadSafeQueue<int>::Popup, &q, std::ref(value)); // 传引用参数的时候需要使用引用包装器std::ref
    std::thread t1(&ThreadSafeQueue<int>::Insert, &q, 10);
    printf("%d\n", value);
    while(!q.Empty());
    t1.join();
    t2.join();
    printf("%d\n", value);
    return 0;
}