select 实现 tcp echo 服务器

最新推荐文章于 2021-05-10 15:18:04 发布

little6256

最新推荐文章于 2021-05-10 15:18:04 发布

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CC 4.0 BY-SA版权

文章标签： tcp socket vector iostream buffer include

本文链接：https://blog.youkuaiyun.com/little6256/article/details/1798724

本文介绍了一个使用C++实现的非阻塞多线程服务器示例，通过WSAStartup初始化套接字库，创建监听套接字并设置非阻塞模式。利用select函数轮询检查连接和数据接收状态，实现并发处理多个客户端连接。

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#include <iostream>
#include <winsock2.h>
#include <vector>
#pragma comment(lib, "ws2_32.lib")
using namespace std;

#define PORT 12345
#define BUFFER_SIZE 1024

int main(int argc, char* argv[])
{
    WSADATA wsaData;
    if(WSAStartup(MAKEWORD(2,2),&wsaData) != 0)
    {
        std::cout << " lib error  ";
        WSACleanup();
        return -1;
    }

    SOCKET listenSocket;
    if((listenSocket = socket(AF_INET, SOCK_STREAM,0)) == INVALID_SOCKET)
    {
        std::cout << "socket error ";
        WSACleanup();
        return -1;
    }

    SOCKADDR_IN addr;
    memset(&addr,0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(PORT);
    addr.sin_addr.s_addr = htonl(ADDR_ANY);

    if(bind(listenSocket,(sockaddr*)&addr,sizeof(addr)) == SOCKET_ERROR)
    {
        std::cout << "bind error ";
        WSACleanup();
        return -1;
    }
    listen(listenSocket,100);

    //将socket设为nonBlock
    u_long nonBlock = 1;
    if(ioctlsocket(listenSocket,FIONBIO,&nonBlock) == SOCKET_ERROR)
    {
        printf("ioctlsocket() error ");
        return -1;
    }

    FD_SET readSet;
    FD_SET writeSet;


    vector<SOCKET> socketArray;
    char buf[BUFFER_SIZE];

    for(;;)
    {
        FD_ZERO(&readSet);
        //FD_ZERO(&writeSet);

        //将listen socket加入，测试是否有新连接
        FD_SET(listenSocket,&readSet);

        //将连接的socket加入readset,测试是否可读
        vector<SOCKET>::iterator it;
        for(it = socketArray.begin(); it != socketArray.end(); ++it)
        {
            FD_SET(*it,&readSet);
            //FD_SET(*it,&writeSet);
        }

        int total = select(0,&readSet,0,NULL,0); //阻塞直到有socket可读
        if(total == SOCKET_ERROR)
        {
            printf("select() error ");
            return -1;
        }

        //判断是否有新连接
        if(FD_ISSET(listenSocket,&readSet))
        {
            SOCKADDR_IN connectAddr;
            int len = sizeof(connectAddr);
            SOCKET socket = accept(listenSocket,(sockaddr*)&connectAddr,&len);
            cout << "new connecter: " << inet_ntoa(connectAddr.sin_addr) <<":" << ntohs(connectAddr.sin_port)<< endl;
            socketArray.push_back(socket);
            total--;
        }

        //检查数组中的socket是否可读
        for(it = socketArray.begin(); total > 0 && it != socketArray.end();)
        {
            if(FD_ISSET(*it,&readSet))
            {
                total--;
                int ret = recv(*it,buf,1024,0);
                if(ret == 0)//对方关闭连接
                {
                    closesocket(*it);
                    it = socketArray.erase(it);//从数组中删除该socket
                }
                else
                {
                    send(*it,buf,ret,0);//echo
                }

            }
            /*

            if(FD_ISSET(*it,&writeSet))
            {

            }
            */
            it++;
        }

    }

    return 0;
}