A simple Thread Pool implementation base on C++14.
Use std::mutex and std::condition_variable , make the Queue thread-safe.
And then use this Safe Queue for the Thread Pool's task queue.
In addition, a close operation is required to accompany the shut down of the thread pool.
Three important elements here:
- Tasks Queue. This is where the work that has to be done is stored. Anyway, it must be thread-safe.
- Thread Pool. This is set of threads (or workers) that continuously take work from the queue and do it.
- Completed Tasks. When the Thread has finished the work we return "something" to notify that the work has finished.
using wrapper_function = std::function<void()>;
// 模板函数 + 可变参数
// 尾返回类型: std::future访问异步操作结果 + decltype自动类型推导 + (参数)通用引用
template <typename _Func, typename... _Args>
auto submit(_Func &&f, _Args &&...args) -> std::future<decltype(f(args...))>
{
// std::function: std::bind绑定绑定函数和参数 + std::forward完美转发
std::function<decltype(f(args...))()> _func = std::bind(std::forward<_Func>(f), std::forward<_Args>(args)...);
// std::make_shared智能指针 + std::packaged_task封装异步调用对象
auto _task_ptr = std::make_shared<std::packaged_task<decltype(f(args...))()>>(_func);
// 类似装饰器的装饰函数 std::function<void()>之后在函数体里调用
wrapper_function _wrap_func = [_task_ptr]() { (*_task_ptr)(); };
// 入队
task_queue_.emplace(_wrap_func);
// get_future拿到结果
return _task_ptr->get_future();
}Someting is need to be the real task worker. That's Thread Worker here. A Thread Worker is a private member class, set up in the Thread Pool as the built-in thread worker class to do the real work.
With the pointer to a ThreadPool, override the () symbol to fetch the wrapper_function from the task queue and execute it.
using wrapper_function = std::function<void()>;
void operator()()
{
wrapper_function _warp_func;
bool _pop_res = false;
while(true)
{
if(!(_pop_res = pool_ptr_->task_queue_.pop(_warp_func)))
{ break; }
if(_pop_res)
{ _warp_func(); }
}
}- 基于C++14的简单线程池
- 使用C++标准库中的线程+锁+条件变量实现并发
- 使用C++14标准库提供的
std::bind，std::forward，std::future，decltype等新特性。