explicit ThreadPool(size_t threads = std::thread::hardware_concurrency()):_stop(false){

for(int i = 0; i < threads; i++){

_works.emplace_back([this]{

while(true){

Task task;

{

std::unique_lock<std::mutex> lock(this->_mtx);

_cv.wait(lock,[this]{

return this->_stop || !this->_tasks.empty();

});

if(this->_stop && this->_tasks.empty()) return;

task = std::move(this->_tasks.front());

this->_tasks.pop();

}

task();//执行任务

}

});

}

}

~ThreadPool(){

{

std::unique_lock<std::mutex> lock(_mtx);

_stop = true;

} // 锁释放

_cv.notify_all();

for(auto &work:_works){

work.join();

}

}

// 提交任务

template<class F, class... Args>

auto enqueue(F&& f, Args&&... args){

auto task = std::bind(std::forward<F>(f), std::forward<Args>(args)...);

{

std::unique_lock<std::mutex> lock(_mtx);

if(_stop) throw std::runtime_error("enqueue on stopped ThreadPool");

_tasks.emplace([task] {task();});

}

_cv.notify_one();// 唤醒一个线程

}

std::mutex _mtx;

std::condition_variable _cv;

bool _stop;

std::vector<std::thread> _works; // 工作线程

std::queue<Task> _tasks; // 任务队列