C++ ThreadPool

gistfile1.txt

class ThreadPool {
public:
    ThreadPool(int num_threads) : stop_(0) {
        for (int i = 0; i < num_threads; ++i) {
            threads_.push_back(std::thread(&ThreadPool::run, this));
        }
    }
    void AddTask(const std::function<void()> &task) {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            queue_.push(task);
        }
        cond_.notify_one();
    }
    ~ThreadPool() {
        stop();
    }

private:
    std::vector<std::thread> threads_;
    void run() {
        std::cout << "start " << std::this_thread::get_id() << endl;
        while (!stop_) {
            std::function<void()> task;
            {
                std::unique_lock<std::mutex> lock(mutex_);
                if (queue_.empty()) {
                    std::cout << "queue is empty" << endl;
                    cond_.wait(lock);
                }
                ///被唤醒可能是因为有任务了
                ///也可能是要退出了，所以要先判断下是否退出
                if (stop_) {
                    std::cout << "stop thread" << std::endl;
                    break;
                }
                ///有可能析构的时候queue里还有任务
                ///导致都被唤醒
                //if (!queue_.empty()) {
                    task = std::move(queue_.front());
                    queue_.pop();
                //}
            }
            task();
        }
        std::cout << "end " << std::this_thread::get_id() << endl;
        return;
    }
    void stop() {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            stop_ = 1;
        }
        cond_.notify_all();
        for (auto &thread : threads_) {
            thread.join();
        }
    }
    std::queue<std::function<void()>> queue_;
    std::mutex mutex_;
    std::condition_variable  cond_;
    int stop_;

};

int main(int argc, const char *argv[])
{
    std::function<void()> f1 = [](){ std::cout << "f1" << std::endl;};
    std::function<void()> f2 = [](){ std::cout << "f2" << std::endl;};
    std::function<void()> f3 = [](){ std::cout << "f3" << std::endl;};
    ThreadPool tp(2);
    tp.AddTask(f1);
    sleep(1);
    std::cout << "sleep 1 ." << std::endl;
    tp.AddTask(f2);
    std::cout << "sleep 2 ." << std::endl;
    tp.AddTask(f3);

    sleep(10);
    return 0;
}

ThreadPool.cc

class ThreadPool {
public:
    ThreadPool(int num_threads) : stop_(0) {
        for (int i = 0; i < num_threads; ++i) {
            threads_.push_back(std::thread(&ThreadPool::run, this));
        }
    }
    void AddTask(const std::function<void()> &task) {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            queue_.push(task);
        }
        cond_.notify_one();
    }
    ~ThreadPool() {
        stop();
    }

private:
    std::vector<std::thread> threads_;
    void run() {
        std::cout << "start " << std::this_thread::get_id() << endl;
        while (!stop_) {
            std::function<void()> task;
            {
                std::unique_lock<std::mutex> lock(mutex_);
                if (queue_.empty()) {
                    std::cout << "queue is empty" << endl;
                    cond_.wait(lock);
                }
                ///被唤醒可能是因为有任务了
                ///也可能是要退出了，所以要先判断下是否退出
                if (stop_) {
                    std::cout << "stop thread" << std::endl;
                    break;
                }
                ///有可能析构的时候queue里还有任务
                ///导致都被唤醒
                //if (!queue_.empty()) {
                    task = std::move(queue_.front());
                    queue_.pop();
                //}
            }
            task();
        }
        std::cout << "end " << std::this_thread::get_id() << endl;
        return;
    }
    void stop() {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            stop_ = 1;
        }
        cond_.notify_all();
        for (auto &thread : threads_) {
            thread.join();
        }
    }
    std::queue<std::function<void()>> queue_;
    std::mutex mutex_;
    std::condition_variable  cond_;
    int stop_;

};

int main(int argc, const char *argv[])
{
    std::function<void()> f1 = [](){ std::cout << "f1" << std::endl;};
    std::function<void()> f2 = [](){ std::cout << "f2" << std::endl;};
    std::function<void()> f3 = [](){ std::cout << "f3" << std::endl;};
    ThreadPool tp(2);
    tp.AddTask(f1);
    sleep(1);
    std::cout << "sleep 1 ." << std::endl;
    tp.AddTask(f2);
    std::cout << "sleep 2 ." << std::endl;
    tp.AddTask(f3);

    sleep(10);
    return 0;
}