操作系统:Linux 64 bit ARCH。

提升:1.46.1

编译器:clang++ / GCC。

我有一个代码片段,其中包含一个以boost::asio示例(Chat Server)为模型的tcp接受器的连线。但是,当我运行该片段时,netstat listening(linux)中未显示任何侦听TCP套接字。但是,聊天服务器示例在编译时确实显示。有人可以指出我做错了吗?

#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/bind.hpp>
#include <list>
#include <iostream>


using namespace boost::asio;
  using namespace boost::asio::ip;

  class ClientConnection
  {
  public:
    ClientConnection(io_service & io_s)
      : m_socket(io_s) {}
    tcp::socket & socket() { return m_socket; }
  private:
    tcp::socket m_socket;
  };

  typedef boost::shared_ptr<ClientConnection> client_connection_ptr;

  class ClientConnectionAcceptor
  {
  public:
    ClientConnectionAcceptor(unsigned short port)
      : m_io_service(),
        m_port(port),
        m_endpoint(tcp::v4(), m_port),
        m_acceptor(m_io_service, m_endpoint)
    {
      std::cout << "acceptor is open : " << m_acceptor.is_open() << std::endl;
      client_connection_ptr ccp(new ClientConnection(m_io_service));

      m_acceptor.async_accept(
        ccp->socket(),
        boost::bind(&ClientConnectionAcceptor::handle_accept,this,
        ccp, placeholders::error));
    }

    void handle_accept(client_connection_ptr ccp, const boost::system::error_code & error)
    {
      std::cout << "in handle_accept" << std::endl;
      if(!error)
      {
       // m_rpc_oracle.AddNewClient(ccp);
        client_connection_ptr new_ccp(new ClientConnection(m_io_service));
        m_acceptor.async_accept(
          new_ccp->socket(),
          boost::bind(&ClientConnectionAcceptor::handle_accept,this,
          ccp, placeholders::error));

      }
    }

    io_service & io_service() { return m_io_service; }
  private:
    boost::asio::io_service m_io_service;
    tcp::endpoint m_endpoint;
    tcp::acceptor m_acceptor;
    unsigned short m_port;
  };


int main()
{
  ClientConnectionAcceptor acceptor(5000);
  acceptor.io_service().run();
}

最佳答案

我发现,如果将endpointacceptor更改为共享指针,则可以在Windows机器上使用它,而不是通过在构造函数中将它们作为参数传递来创建它们,而是专门在构造函数内部创建了共享指针。我不确定为什么会这样。我唯一的猜测是,也许不能保证构造函数参数按其出现的顺序传递或创建,因此您可以尝试使用尚未正确初始化的acceptor创建endpoint吗?那真的是我唯一的猜测。让我知道这是否适合您。我可以通过localhost端口上的5000成功连接。

没有这些更改,我尝试通过localhost与之连接的客户端告诉我该连接被主动拒绝。但是,这种安排是成功的,并且似乎与原始代码的偏差尽可能小。希望能帮助到你。

#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/bind.hpp>
#include <list>
#include <iostream>

using namespace boost::asio;
using namespace boost::asio::ip;

class ClientConnection
{
public:
  ClientConnection(io_service & io_s)
    : m_socket(io_s) {}
  tcp::socket & socket() { return m_socket; }
private:
  tcp::socket m_socket;
};

typedef boost::shared_ptr<ClientConnection> client_connection_ptr;

class ClientConnectionAcceptor
{
public:
  ClientConnectionAcceptor(unsigned short port)
    : m_io_service(),
    m_port(port)
  {
    // now initializing endpoint and acceptor as shared pointers inside the constructor
    m_endpoint = boost::shared_ptr<tcp::endpoint>(new tcp::endpoint(tcp::v4(), m_port));
    m_acceptor = boost::shared_ptr<tcp::acceptor>(new tcp::acceptor(m_io_service, *m_endpoint));

    std::cout << "acceptor is open : " << m_acceptor->is_open() << std::endl;
    client_connection_ptr ccp(new ClientConnection(m_io_service));

    m_acceptor->async_accept(
      ccp->socket(),
      boost::bind(&ClientConnectionAcceptor::handle_accept,this,
      ccp, placeholders::error));
  }

  void handle_accept(client_connection_ptr ccp, const boost::system::error_code & error)
  {
    std::cout << "in handle_accept" << std::endl;
    if(!error)
    {
      // m_rpc_oracle.AddNewClient(ccp);
      client_connection_ptr new_ccp(new ClientConnection(m_io_service));
      m_acceptor->async_accept(
        new_ccp->socket(),
        boost::bind(&ClientConnectionAcceptor::handle_accept,this,
        ccp, placeholders::error));

    }
  }

  io_service & io_service() { return m_io_service; }
private:
  boost::asio::io_service m_io_service;
  boost::shared_ptr<tcp::endpoint> m_endpoint;
  boost::shared_ptr<tcp::acceptor> m_acceptor;
  unsigned short m_port;
};


int main()
{
  ClientConnectionAcceptor acceptor(5000);
  acceptor.io_service().run();
}

编辑

经过进一步调查后,发现问题实际上与ClientConnectionAcceptor类的初始化列表有关。在类定义中,成员m_portm_endpointm_acceptor之后声明。结果,即使初始化程序列表似乎在创建endpointacceptor之前就设置了端口号,但实际上,端口值是无效的或未初始化,直到之后已经创建了endpointacceptor。更改类定义以在m_portendpoint之前声明成员acceptor可解决此问题。

关于c++ - Boost ASIO异步接受器未打开监听端口,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/6665284/

10-11 04:24