C++ socket 多客户端连接

服务端

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

DWORD WINAPI ServerThread(LPVOID lpParameter)
{
    SOCKET ClientSocket = *(SOCKET*)lpParameter;
    char serverBuffer[100] = { 0 };//缓冲区
    while (1)
    {
        //客户端CloseSocket时,服务端recv()返回-1
        if (recv(ClientSocket, serverBuffer, sizeof(serverBuffer), 0) == -1)
        {
            break;
        }
        send(ClientSocket, serverBuffer, sizeof(serverBuffer), 0);
        memset(serverBuffer, 0, sizeof(serverBuffer));  //重置缓冲区
    }
    //关闭监听套接字
    closesocket(ClientSocket);

    return 0;
}



int main() {
    //初始化 DLL
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);

    //创建套接字
    SOCKET servSockToListen = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

    //绑定套接字
    sockaddr_in sockAddr;
    memset(&sockAddr, 0, sizeof(sockAddr));  //每个字节都用0填充
    sockAddr.sin_family = PF_INET;  //使用IPv4地址
    sockAddr.sin_addr.s_addr = htonl(INADDR_ANY);  //具体的IP地址
    sockAddr.sin_port = htons(9999);  //端口
    bind(servSockToListen, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));

    //设置监听状态
    listen(servSockToListen, 20);

    while(1)
    {
        //接收客户端请求
        SOCKADDR clntAddr;
        int nSize = sizeof(SOCKADDR);
        
        //accept阻塞
        SOCKET clntSock = accept(servSockToListen, (SOCKADDR*)&clntAddr, &nSize);

        cout << "一个客户端已连接到服务器，socket是：" << clntSock << endl;
        //为每一个线程创建一个线程
        CreateThread(NULL, 0, &ServerThread, &clntSock, 0, NULL);
    }

    //关闭监听套接字
    closesocket(servSockToListen);

    //终止 DLL 的使用
    WSACleanup();
    return 0;
}

---

客户端

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

int main() {
    //初始化 DLL
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);

    //创建套接字
    SOCKET servSockToContect = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

    //绑定套接字
    sockaddr_in sockAddr;
    memset(&sockAddr, 0, sizeof(sockAddr));  
    sockAddr.sin_family = PF_INET;  
    sockAddr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    sockAddr.sin_port = htons(9999); 

    //connect阻塞
    connect(servSockToContect, (SOCKADDR*)&sockAddr, sizeof(SOCKADDR));


    char sendBuffer[100] = { 0 };
    char clientBuffer[100] = { 0 };

    while (1)
    {
        cout << "请输入要发送的信息,按回车结束发送：" << endl;

        cin.getline(sendBuffer, sizeof(sendBuffer));

        if (strcmp(sendBuffer, "off") == 0)
        {
            break;
        }
        send(servSockToContect, sendBuffer, sizeof(sendBuffer), 0);
        recv(servSockToContect, clientBuffer, sizeof(clientBuffer), 0);
        cout << clientBuffer << endl;

        memset(sendBuffer, 0, sizeof(sendBuffer));  //重置缓冲区
        memset(clientBuffer, 0, sizeof(clientBuffer));  //重置缓冲区
    }

    //关闭套接字
    closesocket(servSockToContect);

    //终止 DLL 的使用
    WSACleanup();

    return 0;
}