Simple Winsock select-modal server-优快云博客

本文链接：https://blog.youkuaiyun.com/EricYeung/article/details/2219172

本文介绍了一个简单的TCP服务器的实现过程，包括使用WSAStartup初始化Winsock环境，创建套接字，绑定端口，监听连接请求，并通过select进行多客户端管理。文章详细展示了如何接收和回传客户端消息。

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void AppMain(int argc, TCHAR* argv[], TCHAR* envp[])
{
    int PortNo = 12345;
    SOCKET ListenSock;
    int Ret = 0;

    WSAData wsa;
    if ((Ret = WSAStartup(MAKEWORD(2,0), &wsa)) != 0)
    {
        printf("WSAStartup() fail.");
        WSACleanup();
        return;
    }

    if ((ListenSock = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
    {
        printf("socket() fail.");
        closesocket(ListenSock);
        WSACleanup();
        return;
    }

    SOCKADDR_IN local;
    local.sin_family = AF_INET;
    local.sin_addr.s_addr = INADDR_ANY;
    local.sin_port = htons(PortNo);

    if ((bind(ListenSock, (struct sockaddr *)&local, sizeof(local)) != 0))
    {
        printf("bind() fail.");
        closesocket(ListenSock);
        WSACleanup();
        return;
    }

    if (listen(ListenSock, 10) != 0)
    {
        printf("listen() fail.");
        closesocket(ListenSock);
        WSACleanup();
        return;
    }

    timeval timeout;
    timeout.tv_sec = 30;
    timeout.tv_usec = 0;

    SOCKET ClientList[FD_SETSIZE];
    SOCKET ClientSock;
    int nCurrClient = 0;
    for(int i = 0; i < FD_SETSIZE; ++i)
        ClientList[i] = INVALID_SOCKET;

    int nSelect = 0;
    fd_set readfds;
    FD_ZERO(&readfds);
    FD_SET(ListenSock, &readfds);
    while(true)
    {
        nSelect = select(0, &readfds, NULL, NULL, &timeout);
        if (FD_ISSET(ListenSock, &readfds))
        {
            ClientSock = accept(ListenSock, NULL, NULL);
            //add to client list
            for(int i = 0; i < FD_SETSIZE; ++i)
            {
                if (INVALID_SOCKET == ClientList[i])
                {
                    ClientList[i] = ClientSock;
                    break;
                }
            }
            if (FD_SETSIZE == i) //list full
            {
                closesocket(ClientSock);
                continue;
            }
        }

        for(int i = 0; i < FD_SETSIZE; ++i)
        {
            char buf[1024] = {0};
            if (FD_ISSET(ClientList[i], &readfds))
            {
                int nRet = recv(ClientList[i], buf, sizeof(buf), 0);
                if (nRet == 0 || nRet == INVALID_SOCKET)
                {
                    closesocket(ClientList[i]);
                    ClientList[i] = INVALID_SOCKET;
                    continue;
                }
                printf("recv: %s/n", buf);
                send(ClientList[i], buf, sizeof(buf), 0);
            }
        }

        FD_ZERO(&readfds);
        FD_SET(ListenSock, &readfds);
        for(int i = 0; i < FD_SETSIZE; ++i)
        {
            if(ClientList[i] != INVALID_SOCKET)
                FD_SET(ClientList[i], &readfds);
        }
    }
}