C++如何实现一个线程池_C++高性能并发编程中的线程池设计与实现

template
class ThreadSafeQueue {
private:
    std::queue queue_;
    mutable std::mutex mtx_;
    std::condition_variable cv_;

public:
    void push(T task) {
        std::lock_guard lock(mtx_);
        queue_.push(std::move(task));
        cv_.notify_one();
    }

    bool try_pop(T& task) {
        std::lock_guard lock(mtx_);
        if (queue_.empty()) return false;
        task = std::move(queue_.front());
        queue_.pop();
        return true;
    }

    void wait_and_pop(T& task) {
        std::unique_lock lock(mtx_);
        cv_.wait(lock, [this] { return !queue_.empty(); });
        task = std::move(queue_.front());
        queue_.pop();
    }
};

class ThreadPool {
private:
    std::vector workers_;
    ThreadSafeQueue> task_queue_;
    std::atomic stop_{false};

    void worker_thread() {
        while (!stop_) {
            std::function task;
            task_queue_.wait_and_pop(task);
            if (task) task();
        }
    }

public:
    explicit ThreadPool(size_t num_threads) {
        for (size_t i = 0; i < num_threads; ++i) {
            workers_.emplace_back(&ThreadPool::worker_thread, this);
        }
    }

    ~ThreadPool() {
        stop_ = true;
        // 唤醒所有等待线程
        // 可以通过向队列中放入空任务来触发退出
        for (auto& t : workers_) {
            if (t.joinable()) t.join();
        }
    }

    template
    void enqueue(F&& f) {
        task_queue_.push(std::forward(f));
    }
};

int main() {
    ThreadPool pool(4); // 创建4个线程

    for (int i = 0; i < 8; ++i) {
        pool.enqueue([i]() {
            std::cout << "Task " << i << " running on thread "
                      << std::this_thread::get_id() << '\n';
            std::this_thread::sleep_for(std::chrono::milliseconds(100));
        });
    }

    // 主线程等待任务完成（实际项目中可加屏障或future）
    std::this_thread::sleep_for(std::chrono::seconds(2));
    return 0;
}