C++ 在构造函数之后初始化boost:：asio套接字

[更新：]对于任何感兴趣的人来说，答案都只是将io_服务成员var包装在boost:：ref（boost:：ref（io_服务））中

我正在使用boost asio库中的udp服务器示例进行实验，以查看是否可以在构造函数之外的其他地方初始化套接字。示例中建议的构造函数如下所示：

class server
{
public:
  server(boost::asio::io_service& io_service, short port)
    : io_service_(io_service),
      socket_(io_service, udp::endpoint(udp::v4(), port))
  {
    socket_.async_receive_from(
        boost::asio::buffer(data_, max_length), sender_endpoint_,
        boost::bind(&server::handle_receive_from, this,
          boost::asio::placeholders::error,
          boost::asio::placeholders::bytes_transferred));
  }

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

using boost::asio::ip::udp;

class server
{
public:
  server(boost::asio::io_service& io_service, short port)
    : io_service_(io_service)
      //socket_(io_service, udp::endpoint(udp::v4(), port))
  {
      initialize_socket(port);
  }

  void initialize_socket(short port)
  {

      socket_p = boost::make_shared<udp::socket>(io_service_, udp::endpoint(udp::v4(), port));
      // (...)
      socket_p->async_receive_from(
              boost::asio::buffer(data_, max_length), sender_endpoint_,
              boost::bind(&server::handle_receive_from, this,
                      boost::asio::placeholders::error,
                      boost::asio::placeholders::bytes_transferred));
  }

  void handle_receive_from(const boost::system::error_code& error,
      size_t bytes_recvd)
  {
    if (!error && bytes_recvd > 0)
    {
      std::cout << "\nReceived: ";
      std::cout.write(data_, bytes_recvd);
      std::cout << "\nSending same string back" << std::endl;
      socket_p->async_send_to(
          boost::asio::buffer(data_, bytes_recvd), sender_endpoint_,
          boost::bind(&server::handle_send_to, this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
    }
    else
    {
      socket_p->async_receive_from(
          boost::asio::buffer(data_, max_length), sender_endpoint_,
          boost::bind(&server::handle_receive_from, this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
    }
  }

  void handle_send_to(const boost::system::error_code& /*error*/,
      size_t /*bytes_sent*/)
  {
    socket_p->async_receive_from(
        boost::asio::buffer(data_, max_length), sender_endpoint_,
        boost::bind(&server::handle_receive_from, this,
          boost::asio::placeholders::error,
          boost::asio::placeholders::bytes_transferred));
  }

private:
  boost::asio::io_service& io_service_;
  boost::shared_ptr<udp::socket> socket_p;
  udp::endpoint sender_endpoint_;
  enum { max_length = 1024 };
  char data_[max_length];
};

int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cerr << "Usage: async_udp_echo_server <port>\n";
      return 1;
    }

    boost::asio::io_service io_service;

    using namespace std; // For atoi.
    server s(io_service, atoi(argv[1]));

    io_service.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }

  return 0;
}

我使套接字成员成为指针，同时也是共享指针，这样我就不必担心它是否超出范围。“io_service_”也是一个成员变量，我使用它来创建套接字。我的完整代码如下：

class server
{
public:
  server(boost::asio::io_service& io_service, short port)
    : io_service_(io_service),
      socket_(io_service, udp::endpoint(udp::v4(), port))
  {
    socket_.async_receive_from(
        boost::asio::buffer(data_, max_length), sender_endpoint_,
        boost::bind(&server::handle_receive_from, this,
          boost::asio::placeholders::error,
          boost::asio::placeholders::bytes_transferred));
  }

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

using boost::asio::ip::udp;

class server
{
public:
  server(boost::asio::io_service& io_service, short port)
    : io_service_(io_service)
      //socket_(io_service, udp::endpoint(udp::v4(), port))
  {
      initialize_socket(port);
  }

  void initialize_socket(short port)
  {

      socket_p = boost::make_shared<udp::socket>(io_service_, udp::endpoint(udp::v4(), port));
      // (...)
      socket_p->async_receive_from(
              boost::asio::buffer(data_, max_length), sender_endpoint_,
              boost::bind(&server::handle_receive_from, this,
                      boost::asio::placeholders::error,
                      boost::asio::placeholders::bytes_transferred));
  }

  void handle_receive_from(const boost::system::error_code& error,
      size_t bytes_recvd)
  {
    if (!error && bytes_recvd > 0)
    {
      std::cout << "\nReceived: ";
      std::cout.write(data_, bytes_recvd);
      std::cout << "\nSending same string back" << std::endl;
      socket_p->async_send_to(
          boost::asio::buffer(data_, bytes_recvd), sender_endpoint_,
          boost::bind(&server::handle_send_to, this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
    }
    else
    {
      socket_p->async_receive_from(
          boost::asio::buffer(data_, max_length), sender_endpoint_,
          boost::bind(&server::handle_receive_from, this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
    }
  }

  void handle_send_to(const boost::system::error_code& /*error*/,
      size_t /*bytes_sent*/)
  {
    socket_p->async_receive_from(
        boost::asio::buffer(data_, max_length), sender_endpoint_,
        boost::bind(&server::handle_receive_from, this,
          boost::asio::placeholders::error,
          boost::asio::placeholders::bytes_transferred));
  }

private:
  boost::asio::io_service& io_service_;
  boost::shared_ptr<udp::socket> socket_p;
  udp::endpoint sender_endpoint_;
  enum { max_length = 1024 };
  char data_[max_length];
};

int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cerr << "Usage: async_udp_echo_server <port>\n";
      return 1;
    }

    boost::asio::io_service io_service;

    using namespace std; // For atoi.
    server s(io_service, atoi(argv[1]));

    io_service.run();
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << "\n";
  }

  return 0;
}

---

有人知道这个实现出了什么问题吗？

这段代码在windows上的code:：Blocks IDE上编译得很好（尽管我将boost:：shared_ptr更改为c++11 std:：shared_ptr）

问题可能存在于boost库的安装或编译器/链接器设置中

编辑：

使用的编译器是mingw_64。Boost版本是1_58_0。

使_共享

复制其参数（如

绑定

或

线程

的命令）。当传递到

make_shared

时，必须将

io_服务

包装在

boost:：ref

中，以确保它作为引用传递：

socket_p=boost:：使_共享（boost:：ref（io_服务），udp:：endpoint（udp:：v4（），port））；

code:：Blocks只是一个可以使用多种编译器之一的IDE。您使用了哪种编译器？@dcook感谢您的通知，附加了我的答案。

make_shared

复制其参数（如bind或thread c'tor）。您必须将

io_服务

包装在

boost:：ref

：

make_shared（boost:：ref（io_服务）…

。太棒了！我怎么能把这个标记为答案呢？：）我做了一个答案。@StefanNäwe，我正在尝试做类似的事情。但是，我没有像io_服务一样的boost:：asio:：io_服务副本，而是使用直接从外部传递的io_服务。我的代码不起作用。这就是原因吗？我改用拷贝（io_服务_）作为OP，但仍然不起作用。我现在已经不知所措了。