c++简单的线程池

#include <iostream>
#include <vector>
#include <queue>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <thread>class ThreadPool {
public:using Task = std::function<void()>;// 构造：启动 threadNum 个工作线程explicit ThreadPool(size_t threadNum) : stop(false) {for (size_t i = 0; i < threadNum; ++i) {workers.emplace_back([this] { worker(); });}}// 析构：停止线程池~ThreadPool() {{std::lock_guard<std::mutex> lock(mtx);stop = true;}cv.notify_all();  // 唤醒所有线程退出for (auto& t : workers) {if (t.joinable()) t.join();}}// 提交任务（生产者）template <class F>void enqueue(F&& f) {{std::lock_guard<std::mutex> lock(mtx);tasks.emplace(std::forward<F>(f));}cv.notify_one();  // 唤醒一个消费者
    }private:// 工作线程（消费者）void worker() {while (true) {Task task;{std::unique_lock<std::mutex> lock(mtx);// 等待：不停止 且 队列为空 → 等待cv.wait(lock, [this] { return stop || !tasks.empty(); });// 线程池停止且队列为空 → 退出if (stop && tasks.empty()) return;// 取任务task = std::move(tasks.front());tasks.pop();}// 执行任务（解锁后执行，避免长时间占锁）if (task) task();}}private:std::vector<std::thread> workers;    // 工作线程std::queue<Task> tasks;              // 任务队列std::mutex mtx;                      // 互斥锁std::condition_variable cv;          // 条件变量bool stop;                           // 停止标志
};// 测试
int main() {ThreadPool pool(4);  // 4个线程// 提交8个任务for (int i = 0; i < 8; ++i) {pool.enqueue([i] {printf("task %d run by thread %lu\n",i, std::this_thread::get_id());std::this_thread::sleep_for(std::chrono::milliseconds(200));});}std::this_thread::sleep_for(std::chrono::seconds(1));std::cout << "all tasks done\n";return 0;
}