项目github   https://github.com/dreamyouxi/LiteHttp

文件ThreadPool.cpp

#include "ThreadPool.h"
#include "winsock.h"
#include "stdlib.h"
#include "stdio.h"
#include "string.h"
#include <fstream>
#include <iostream>
#include <string>
#include <atomic>
#include "Defs.h"
#include "FileCache.h"
#include "HttpRequest.h"
#include "HttpRespone.h"

using namespace std;


void SendThread(HttpRespone* rep)
{
    send(rep->sock, (const char*)rep->header, rep->header_size, 0);
    send(rep->sock, (const char*)rep->buffer,rep->size, 0);

}

class ThreadCounterRAII
{
public:
    ThreadCounterRAII()
    {
        _count.fetch_add(1);
    }

    static atomic<int > _count;
    ~ThreadCounterRAII()
    {
        _count.fetch_sub(1);
    }

};

atomic<int>  ThreadCounterRAII::_count = 0;

void ProcessRequestThread(HttpRequest*request )
{
    ThreadCounterRAII counter;
    ..........
}


ThreadPool * ThreadPool::getInstance()
{
    static ThreadPool * ins = nullptr;
    if (!ins)ins = new ThreadPool;
    return ins;
}



void ThreadPool::WorkThread()
{
    while (true)
    {
        this->_mutex.lock();
        while(this->works.empty())
        {
            this->_cond.wait(this->_mutex);
        }
        HttpRequest * req =  this->works.front();
        this->works.pop();
        this->_mutex.unlock();
        ProcessRequestThread(req);
    }
}


void  ThreadPool::addTask(HttpRequest*work)
{
    this->_mutex.lock();
    this->works.push(work);
    this->_mutex.unlock();

    this->_cond.notify_one();
}

ThreadPool::ThreadPool()
{
    int MAX_THREADS = std::thread::hardware_concurrency();

    while (MAX_THREADS--)
    {
        std::thread t(std::bind(&ThreadPool::WorkThread, this));

        t.detach();
        this->workers.push_back(std::move(t));
    }
}

程序初始化时启动 10个工作线程，主线程接收到的TCP链接请求全部加入请求队列，工作线程处理

主线程：Application.cpp

    while (true)
    {
        int sock_client = accept(sock, (sockaddr *)&client_ipaddr, &length);
        if (sock_client == SOCKET_ERROR)
        {
            return;
        }
        HttpRequest*req = new HttpRequest;
        req->sock = sock_client;
        ThreadPool::getInstance()->addTask(req);
    }