误差成员函数指针，助推绑定

Question

予编码，其连接到一台服务器在单个文件中没有任何类的客户端。这显然心不是编程的一个很好的方式，所以当代码最终表现为我想，我创建了myclient类具有以下client.h：

#include <boost/asio.hpp> 
    #include <boost/array.hpp> 
    #include <iostream> 
    #include <string> 
    #include "mtbf.h" 
    #include <boost/date_time/posix_time/posix_time.hpp> 

    class myclient 
    { 
    public: 
    boost::asio::io_service io_service; 
    boost::asio::ip::tcp::resolver resolver; 
    boost::asio::ip::tcp::socket sock; 
    boost::array<char, 4096> buffer; 
    typedef boost::posix_time::time_duration duration_t; 
    typedef boost::posix_time::ptime timestamp_t; 
    std::vector<std::string> tokens; 
    boost::system::error_code m_err_feedback; 



      enum ConnectionState 
     { 
      WAIT_FOR_HEADER, 
      WAIT_FOR_DATA, 
      PACKET_COMPLETE 
     }; 
    myclient(std::string port); 
    private: 
     void read_handler(const boost::system::error_code &ec, std::size_t bytes_transferred); 
     void connect_handler(const boost::system::error_code &ec); 
     void resolve_handler(const boost::system::error_code &ec, boost::asio::ip::tcp::resolver::iterator it); 

    }; 

我不写client.cpp的全部代码，但这里是错误发生时（构造函数）

myclient::myclient(std::string port):resolver(io_service),sock(io_service) 
    { 
     tcp::resolver::query query("127.0.0.1", port); 
     resolver.async_resolve(query, boost::bind(&myclient::resolve_handler, this)); 
     io_service.run(); 
    } 

我是相当新的C++，但我得到我需要一个boost ::绑定来调用

resolver.async_resolve(query, boost::bind(&myclient::resolve_handler, this)); 

一个成员函数的引用

但不知何故小号心不是很right..i得到一个错误：

error 8 error C2298: 'return': Invalid procedure for an expression with pointer to memberfunction C:\projekte\libs\boost_1_53_0-VC11\boost\bind\mem_fn.hpp 342 1 client 

编辑：感谢您reply..but似乎还有更多的只是未来的错误。我错过了一些微不足道的东西吗？下面是从client.cpp代码（我删除了实际算法read_handler因为它不重要）

#include "client.h" 
    using boost::asio::ip::tcp; 

    myclient::myclient(std::string port):resolver(io_service),sock(io_service) 
    { 
     tcp::resolver::query query("127.0.0.1", port); 
     resolver.async_resolve(query, boost::bind(&myclient::resolve_handler, this,boost::asio::placeholders::error,boost::asio::placeholders::iterator)); 
     io_service.run(); 
    } 

    void myclient::read_handler(const boost::system::error_code &ec, std::size_t bytes_transferred) 
    { 

    . 
    . 
    . 


    } 

    void myclient::connect_handler(const boost::system::error_code &ec) 
    { 
     if (!ec) 
     { 
     sock.async_read_some(boost::asio::buffer(buffer), boost::bind(&myclient::read_handler, this,&ec)); 
     } 
    } 

    void myclient::resolve_handler(const boost::system::error_code &ec, boost::asio::ip::tcp::resolver::iterator it) 
    { 
     if (!ec) 
     { 
     sock.async_connect(*it, boost::bind(&myclient::connect_handler, this, &ec, it)); 
     } 
    } 

有了这个，我得到这样的错误：

error 2 error C2825: "F": must be a class or namespace "::". C:\projekte\libs\boost_1_53_0-VC11\boost\bind\bind.hpp 69 1 client 
error 3 error C2039: 'result_type': is not an element of '`global namespace'' C:\projekte\libs\boost_1_53_0-VC11\boost\bind\bind.hpp 69 1 client 

Answer 1

你忘了占位符来传递参数到resolve_handler：

boost::bind(&myclient::resolve_handler, this, 
    boost::asio::placeholders::error, 
    boost::asio::placeholders::iterator)