socket（套接字）

Posted 2020-06-24 dongerlei

客户端：

• 创建套接字（socket）
• 连接服务器（connect）
• 通信（send，recv或者write，read）
• 关闭套接字（closesocket）

示例代码：

int main(int argc, char* argv[])
{
    const int BUF_SIZE = 64;
    WSADATA            wsd;            //WSADATA变量
    SOCKET            sHost;            //服务器套接字
    SOCKADDR_IN        servAddr;        //服务器地址
    char            buf[BUF_SIZE];    //接收数据缓冲区
    char            bufRecv[BUF_SIZE];
    int                retVal;            //返回值

    //初始化套结字动态库
    if (WSAStartup(MAKEWORD(2, 2), &wsd) != 0)
    {
        cout << "WSAStartup failed!" << endl;
        return -1;
    }

    //创建套接字
    sHost = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (INVALID_SOCKET == sHost)
    {
        cout << "socket failed!" << endl;
        WSACleanup();//释放套接字资源
        return  -1;
    }
    //设置服务器地址
    servAddr.sin_family = AF_INET;
    servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    servAddr.sin_port = htons((short)4999);
    int    nServAddlen = sizeof(servAddr);
    //连接服务器
    retVal = connect(sHost, (LPSOCKADDR)&servAddr, sizeof(servAddr));
    if (SOCKET_ERROR == retVal)
    {
        cout << "connect failed!" << endl;
        closesocket(sHost);    //关闭套接字
        WSACleanup();        //释放套接字资源
        return -1;
    }
    while (true){
        //向服务器发送数据
        ZeroMemory(buf, BUF_SIZE);
        cout << " 向服务器发送数据:  ";
        cin >> buf;
        retVal = send(sHost, buf, strlen(buf), 0);
        if (SOCKET_ERROR == retVal)
        {
            cout << "send failed!" << endl;
            closesocket(sHost);    //关闭套接字
            WSACleanup();        //释放套接字资源
            return -1;
        }
        //RecvLine(sHost, bufRecv);
        recv(sHost, bufRecv, 5, 0);        // 接收服务器端的数据， 只接收5个字符
        cout << endl << "从服务器接收数据：" << bufRecv;
    }
    //退出
    closesocket(sHost);    //关闭套接字
    WSACleanup();        //释放套接字资源
    return 0;
}

服务端：

• 创建套接字（socket）
• 绑定套接字（bind）
• 开启监听（listen）
• 接受请求（accept）
• 通信（send，recv或者write，read）
• 关闭套接字（closesocket）

示例代码：

int _tmain(int argc, char* argv[])
{
    const int BUF_SIZE = 64;
    WSADATA            wsd;            //WSADATA变量
    SOCKET            sServer;        //服务器套接字
    SOCKET            sClient;        //客户端套接字
    SOCKADDR_IN        addrServ;;        //服务器地址
    char            buf[BUF_SIZE];    //接收数据缓冲区
    char            sendBuf[BUF_SIZE];//返回给客户端得数据
    int                retVal;            //返回值
    //初始化套结字动态库
    if (WSAStartup(MAKEWORD(2, 2), &wsd) != 0)
    {
        cout << "WSAStartup failed!" << endl;
        return 1;
    }

    //创建套接字
    sServer = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (INVALID_SOCKET == sServer)
    {
        cout << "socket failed!" << endl;
        WSACleanup();//释放套接字资源;
        return  -1;
    }

    //服务器套接字地址 
    addrServ.sin_family = AF_INET;
    addrServ.sin_port = htons(4999);
    addrServ.sin_addr.s_addr = INADDR_ANY;
    //绑定套接字
    retVal = bind(sServer, (LPSOCKADDR)&addrServ, sizeof(SOCKADDR_IN));
    if (SOCKET_ERROR == retVal)
    {
        cout << "bind failed!" << endl;
        closesocket(sServer);    //关闭套接字
        WSACleanup();            //释放套接字资源;
        return -1;
    }

    //开始监听 
    retVal = listen(sServer, 1);
    if (SOCKET_ERROR == retVal)
    {
        cout << "listen failed!" << endl;
        closesocket(sServer);    //关闭套接字
        WSACleanup();            //释放套接字资源;
        return -1;
    }

    //接受客户端请求
    sockaddr_in addrClient;
    int addrClientlen = sizeof(addrClient);
    sClient = accept(sServer, (sockaddr FAR*)&addrClient, &addrClientlen);
    if (INVALID_SOCKET == sClient)
    {
        cout << "accept failed!" << endl;
        closesocket(sServer);    //关闭套接字
        WSACleanup();            //释放套接字资源;
        return -1;
    }

    while (true){
        //接收客户端数据
        ZeroMemory(buf, BUF_SIZE);
        retVal = recv(sClient, buf, BUF_SIZE, 0);
        if (SOCKET_ERROR == retVal)
        {
            cout << "recv failed!" << endl;
            closesocket(sServer);    //关闭套接字
            closesocket(sClient);    //关闭套接字        
            WSACleanup();            //释放套接字资源;
            return -1;
        }
        if (buf[0] == ‘0‘)
            break;
        cout << "客户端发送的数据: " << buf << endl;

        cout << "向客户端发送数据: ";
        cin >> sendBuf;

        send(sClient, sendBuf, strlen(sendBuf), 0);
    }

    //退出
    closesocket(sServer);    //关闭套接字
    closesocket(sClient);    //关闭套接字
    WSACleanup();            //释放套接字资源;

    return 0;
}