c++ 使用mutex cond 实现 Barrier

class Barrier{
private:
    uv_mutex_t mutex;
    uv_cond_t cond;
    int number;
public:
    Barrier(int number){
        this->number = number;
        uv_cond_init(&cond);
        uv_mutex_init(&mutex);
    }
    void wait(){
        uv_mutex_lock(&mutex);
        --number;
        if(number > 0){
            uv_cond_wait(&cond, &mutex);
        }
        else{
            uv_cond_broadcast(&cond);
        }
        uv_mutex_unlock(&mutex);
    }
    ~Barrier(){
        std::cout << "~Barrier" << std::endl;
        uv_mutex_destroy(&mutex);
        uv_cond_destroy(&cond);
    }
};

int main(const int argc, const char * argv[]) {
    Barrier barrier(5);
    uv_thread_t tids[5];
    for(int i = 0;i < 4;i++){
        uv_thread_create(&tids[i], [](void *data){
            Barrier* const barrier = (Barrier *)data;
            barrier->wait();
            std::cout << "Thread done!" << std::endl;
        }, &barrier);
    }
    std::cout << "main thread wait!" << std::endl;
    for(int i = 0; i < INT_MAX >> 1;++i){
        
    }
     std::cout << "main thread wait done!" << std::endl;
    barrier.wait();
    for(int i = 0; i < INT_MAX >> 1;++i){
        
    }
    std::cout << "done!" << std::endl;
}

运行输出

main thread wait!
main thread wait done!
Thread done!
Thread done!
Thread done!
Thread done!
done!
~Barrier
Program ended with exit code: 0