C++如何实现线程池 C++线程池的设计与实现方法详解

#include <iostream>
#include <vector>
#include <queue>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>

class ThreadPool {
public:
    ThreadPool(size_t numThreads) : numThreads_(numThreads), stop_(false) {
        threads_.reserve(numThreads_);
        for (size_t i = 0; i < numThreads_; ++i) {
            threads_.emplace_back([this] {
                while (true) {
                    std::function<void()> task;
                    {
                        std::unique_lock<std::mutex> lock(queueMutex_);
                        cv_.wait(lock, [this] { return stop_ || !tasks_.empty(); });
                        if (stop_ && tasks_.empty())
                            return;
                        task = std::move(tasks_.front());
                        tasks_.pop();
                    }
                    task();
                }
            });
        }
    }

    template<typename F>
    void enqueue(F&& f) {
        {
            std::unique_lock<std::mutex> lock(queueMutex_);
            tasks_.emplace(std::forward<F>(f));
        }
        cv_.notify_one();
    }

    ~ThreadPool() {
        {
            std::unique_lock<std::mutex> lock(queueMutex_);
            stop_ = true;
        }
        cv_.notify_all();
        for (std::thread& thread : threads_) {
            thread.join();
        }
    }

private:
    size_t numThreads_;
    std::vector<std::thread> threads_;
    std::queue<std::function<void()>> tasks_;
    std::mutex queueMutex_;
    std::condition_variable cv_;
    bool stop_;
};

int main() {
    ThreadPool pool(4); // 创建一个包含4个线程的线程池

    for (int i = 0; i < 8; ++i) {
        pool.enqueue([i] {
            std::cout << "Task " << i << " is running in thread " << std::this_thread::get_id() << std::endl;
            std::this_thread::sleep_for(std::chrono::seconds(1));
        });
    }
    std::this_thread::sleep_for(std::chrono::seconds(3)); // 等待任务完成
    return 0;
}