#include 
     
                      // std::cout#include 
      
                       // std::thread#include 
       
                        // std::mutex, std::unique_lock#include 
        
             // std::condition_variablestd::mutex mtx;std::condition_variable cv;int cargo = 0; // shared value by producers and consumersvoid consumer(){    std::unique_lock < std::mutex > lck(mtx);    while (cargo == 0)        cv.wait(lck);    std::cout << cargo << '\n';    cargo = 0;}void producer(int id){    std::unique_lock < std::mutex > lck(mtx);    cargo = id;    cv.notify_one();//如果存在多个等待唤醒的线程则唤醒的线程时不确定的}int main(){    std::thread consumers[10], producers[10];　　//多个生产者，多个消费者，只要加锁还是安全的    // spawn 10 consumers and 10 producers:    for (int i = 0; i < 10; ++i) {        consumers[i] = std::thread(consumer);//消费者线程        producers[i] = std::thread(producer, i + 1);//生产者线程    }    // join them back:    for (int i = 0; i < 10; ++i) {        producers[i].join();        consumers[i].join();    }    getchar();    return 0;}
        
       
      
     

 通常std::condition_variable使用std::unique_lock锁住线程，如果使用其的可以用std::condition_variable_any