如何在不关闭的情况下发送套接字？ [英] How do I get the socket to send without close?

问题描述

嘿伙计们，



我对c ++很陌生，但我正在尝试编写一个双向套接字连接（一个用于发送充当客户端和一个接收充当服务器）。



接收部分工作正常，但发送部分有问题。



如果我关闭套接字，只想发送的消息会发送，并且有问题，我无法关闭套接字，因为服务器（在这种情况下是其他程序）期望套接字保持打开状态。



有没有办法在不关闭发送套接字的情况下发送消息？

Hey guys,

I am pretty new to c++, but I am trying to program a two way socket connection (one for sending acts as a client and one for receiving acts as a server).

The receive part works perfectly, but I have a problem with the sending part.

The message want to send only gets send if I close the socket, and there is the problem, I can't close the socket because the server ( in this case an other program) expects the socket to stay open.

Is there any way I can send the message without closing the sending socket?

if (function == "connect" ){
    status_s = getaddrinfo(&host_const[0], &port_const[0], &host_info_s, &host_info_list_s);

    if (status_s != 0)  std::cout << "getaddrinfo error" << gai_strerror(status_s) ;


    std::cout << "Creating a sending socket..."  << std::endl;
    socketfd_s = socket(host_info_list->ai_family, host_info_list->ai_socktype,
                      host_info_list->ai_protocol);
    if (socketfd_s == -1)  std::cout << "socket error " ;

    std::cout << "Host: " << &host_const[0] << std::endl;
    std::cout << "Port: " << &port_const[0] << std::endl;
    std::cout << "function: " << function << std::endl;
    function.erase(std::remove(function.begin(), function.end(), '\n'), function.end());

    std::cout << "Connect()ing..."  << std::endl;
    status_s = connect(socketfd_s, host_info_list_s->ai_addr, host_info_list_s->ai_addrlen);
    if (status_s == -1)  std::cout << "connect error" ;
    cout << "status: " << status_s;
    cout << "socket connector:                       " << socketfd_s ;



    std::cout << "client connected....."  << std::endl;
   }
   else {//if (function != "connect" )
        std::cout << "send()ing message on anwser..."  << std::endl;
        char *msg_s = "some_string";
        int len_s;
        ssize_t bytes_sent_s;
        std::cout << msg_s;
        len_s = strlen(msg_s);
        std::cout << len_s << std::endl;
        std::cout << "Message not sent...."  << std::endl;
        //send(socketfd_s, msg_s, len_s, 0);
        bytes_sent_s = sendto(socketfd_s, msg_s, len_s, 0, host_info_list_s->ai_addr, host_info_list_s->ai_addrlen);
        freeaddrinfo(host_info_list);
        //close(socketfd_s);

        //bytes_sent_s = send(socketfd_s, msg_s, len_s, 0);
        //send(socketfd_s, msg_s, len_s, 0);
        std::cout << "Message sent....\n"  << std::endl;
        std::cin.ignore();
        cout << "param1" << socketfd_s;
        cout << "param2" << len_s;
        cout << "param3" << msg_s;
}

连接到套接字工作正常，只是其他部分就是问题，你可以看到我已经尝试过发送和发送，但结果相同。



啊和整个thing在while（1）循环中运行以读取多条消息。



谢谢

The connect to the socket works perfectly, just the else part is the problem, as you can see I already tried send and sendto, but had the same result.

Ah and the whole thing runs in a while (1) loop to read more than one message.

Thank you

推荐答案

您应该使用发送来发送消息，而不是 sendto ，这是针对无连接套接字的。请参见 http://linux.die.net/man/2/sendto [ ^ ]。

You should be using send to send your messages, rather than sendto, which is for connectionless sockets. See http://linux.die.net/man/2/sendto[^].

我建​​议你试试您可以在此页面中找到的代码示例：套接字教程 [ ^ ]。

I suggest you to try the code sample you may find in this page: "Sockets Tutorial"[^].

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