简单好用的threadPool (90行代码)【摘自改编于httplib源码】

今天在看cpp-httplib的源码， 发现其中的threadPool 线程词写的很简单, 而且很多的知识点，
直接把这部分代码摘抄出来,稍微改了一下,就能单独的使用并且跑起来了

全部实现如下 90行代码，复制出来0改动直接可使用
大家主要自己看下这块，思想和写法都不错，很简洁

#include <iostream>
#include <functional>
#include <mutex>
#include <condition_variable>
#include <vector>
#include <thread>
#include <list>using Task = std::function<void()>;class TaskQueue {
public:TaskQueue() = default;virtual ~TaskQueue() = default;virtual void enqueue(const Task&) = 0;virtual void shutdown() = 0;
};class ThreadPool : public TaskQueue {
public:explicit ThreadPool(size_t n) {while (n){m_threads.emplace_back(worker(*this));n--;}}ThreadPool(const ThreadPool&) = delete;~ThreadPool() override = default;void enqueue(const Task& task) override {{std::unique_lock<std::mutex> lock(m_mutex);m_tasks.push_back(task);}m_cond.notify_one();}void shutdown() override {{std::unique_lock<std::mutex> lock(m_mutex);m_shutdown = true;}m_cond.notify_all();for (auto& t : m_threads) {t.join();}}private:struct worker {explicit worker(ThreadPool& pool) : m_pool(pool) {}void operator()() {for (;;) {Task task;{std::unique_lock<std::mutex> lock(m_pool.m_mutex);m_pool.m_cond.wait(lock, [&] {return !m_pool.m_tasks.empty() || m_pool.m_shutdown; });if (m_pool.m_tasks.empty() && m_pool.m_shutdown)break;task = std::move(m_pool.m_tasks.front());m_pool.m_tasks.pop_front();}task();}}ThreadPool& m_pool;};friend struct worker;private:bool m_shutdown = false;std::vector<std::thread> m_threads;std::list<Task> m_tasks;std::condition_variable m_cond;std::mutex m_mutex;
};

用例

/testcase/void work1() {for (auto i = 0; i < 10000; i++)std::cout << "i am work1:" << i <<"threadId:"<< std::this_thread::get_id() << std::endl;
}void work2() {for (auto i = 0; i < 10000; i++)std::cout << "i am work2:" << i << "threadId:" << std::this_thread::get_id() << std::endl;
}void work3() {for (auto i = 0; i < 10000; i++)std::cout << "i am work3:" << i << "threadId:" << std::this_thread::get_id() << std::endl;
}//int main()
{TaskQueue* queue = new ThreadPool(3);queue->enqueue(work1);queue->enqueue(work2);queue->enqueue(work3);while (true) {}return 0;
}

运行图: