[Boost-users] [asio] documentation example, bind semantics

Subject: [Boost-users] [asio] documentation example, bind semantics
From: John M. Dlugosz (mpbecey7gu_at_[hidden])
Date: 2012-05-03 02:59:30

In boost_asio/tutorial/tutdaytime3.html, the code shown is:

  void  handle_accept(tcp_connection::pointer  new_connection,
       const  boost::system::error_code&  error)
   {

and is called via a function object:
  boost::bind(&tcp_server::handle_accept,  this,  new_connection,
           boost::asio::placeholders::error)

I get after my coworkers I'm mentoring in the area of C++ skills to pass smart pointers by 
const-ref not by value, since the atomic inc/dec is very costly.

I believe that a boost::function (and now std::function) will hold the object by value 
even if the function being bound declares it as reference, and the INVOKE phase will bind 
the parameter to the stored copy in the function object.

So handle_accept can and should be declared as using a

const tcp_connection::pointer&

as well, right?  Is there any reason not to?

—John