c++ - 为什么 boost::asio 似乎什么都不做

Question

我正在尝试以非常基本的方式实现 irc 协议(protocol)。我的第一次尝试是使用 boost::asio 并连接到服务器并读取 motd。 AFAIK motd 在连接时发送给每个客户端。我制作了以下测试程序，但似乎什么也没做。这不是一段很好的代码，但这是我在几个令人沮丧的小时后所拥有的全部代码。

#define _WIN32_WINNT 0x0501
#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/function.hpp>
#include <queue>



class IrcConnection
{
public:
    IrcConnection(const std::string& server, int port, boost::function<void (const std::string&)> onMessage, boost::asio::io_service& io_service): s(server), p(port), onM(onMessage), ios(io_service), socket(io_service)
    {
    }
    void connect() 
    {
        somethingHappened = false;
        //DNS stuff
        boost::asio::ip::tcp::resolver resolver(ios);
        boost::asio::ip::tcp::resolver::query query(s , "0");
        boost::asio::ip::tcp::resolver::iterator iter = resolver.resolve(query);
        boost::asio::ip::tcp::resolver::iterator end;

        boost::system::error_code error;

        while(iter != end)
        {
            boost::asio::ip::tcp::endpoint endpoint = iter->endpoint();
            endpoint.port(p);
            socket.close();
            socket.connect(endpoint, error);
            iter++;
        }
        if(error)
        {
            std::cout << "ERROR" << std::endl;
            std::cout << error << std::endl;
        }

        std::cout << "Connected to: " << socket.remote_endpoint().address().to_string() << std::endl; 

        //read from the socket until a space is found
        boost::asio::async_read_until(socket, currentData, ' ', boost::bind(&IrcConnection::onReceiveFinished, this, boost::asio::placeholders::error));
    }
    void disconnect() 
    {
        socket.close();
    }
    void send(int priority, const std::string& message) 
    {
    }
bool somethingHappened;

private:
    std::string s;
    int p;
    boost::function<void (const std::string&)> onM;
    boost::asio::io_service& ios;
    boost::asio::ip::tcp::socket socket;
    std::priority_queue<std::string> outQueue;
    boost::asio::streambuf currentData;


    void onReceiveFinished(const boost::system::error_code& error)
    {
        if(error)
        {
            disconnect();
            std::cout << "ERRORRRR" << std::endl;
            std::cout << error << std::endl;
        }

        std::cout << "STUFF IS OCCURING" << std::endl;
        somethingHappened = true;

         std::istream stream(&currentData);
         std::string data;
         std::getline(stream, data);

         boost::asio::async_read_until(socket, currentData, ' ', boost::bind(&IrcConnection::onReceiveFinished, this, boost::asio::placeholders::error));
         ios.dispatch(boost::bind(onM, data));
    }


};


void onMe(const std::string& x)
{
    std::cout << "MESSAGE" << std::endl;
    std::cout << x << std::endl;
}

int main()
{
    boost::asio::io_service ios;
    std::string server = "irc.efnet.org";
    int port = 6667;

    IrcConnection x(server, port, onMe, ios);

    x.connect();

    while(!x.somethingHappened)
    {
        //
    }

    return 0;

}

该程序尝试连接到 irc.efnet.org 并读取直到发送了一个空格，然后将该数据吐出到终端。但是我运行它，所有打印的都是我连接的 IP 地址，然后程序不会终止。

我需要做什么才能获得缩进行为？

Answer 1

如果您正在进行异步调用，则必须向 io_service 发送请求。在您的情况下，在 "x.connect();" 之后，您应该调用 "ios.run();"

请记住，如果您在异步回调返回后不进行任何进一步的发布，run 将退出/返回。

顺便说一句，在 "ios.dispatch(boost::bind(onM, data));" 中，onM 意味着 onMe 吗？