boost::bind

CTCPClient::CTCPClient(std::string _host, int port)
    :socket_(io_service_)
{
    boost::asio::ip::tcp::endpoint endpoint(boost::asio::ip::address::from_string(_host), port);
    socket_.async_connect(endpoint, boost::bind(&CTCPClient::handle_connect, this));
}
 
void CTCPClient::handle_connect(const boost::system::error_code& error)
{
    if (!error)
    {
    } 
}

boost::bind(&CTCPClient::handle_connect, this, _1);

boost::bind(&CTCPClient::handle_connect, this, boost::asio::placeholders::error);

typedef void __stdcall iidk_callback_ex(const char*, const char*, unsigned long);
 
void __stdcall My_Callback( const char *, char *, unsigned long )
{
...
}
 
int CSomeClass::Connect( const std::string & SessionID, const std::string & ServerPort )
{
    iidk_callback_ex* callback_func = 0;
....
    callback_func = (iidk_callback_ex*)My_Callback;
    ConnectEx( connectIP.c_str(),
                            ServerPort.c_str(),
                            SessionID.c_str(),
                            callback_func,
                            (unsigned long)ID, 1, 10 );
....
}

boost::function<void (const char *, const char *, unsigned long)>callback_func;
callback_func = boost::bind(&CSomeClass::My_Callback, this, _1, _2, _3);
....