libs/asio/doc/requirements/ComposedConnectHandler.qbk

[/
 / Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com)
 /
 / Distributed under the Boost Software License, Version 1.0. (See accompanying
 / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 /]

[section:ComposedConnectHandler Composed connect handler requirements]

A composed connect handler must meet the requirements for a [link
boost_asio.reference.Handler handler]. A value `h` of a composed connect handler
class should work correctly in the expression `h(ec, i)`, where `ec` is an
lvalue of type `const error_code` and `i` is an lvalue of the type `Iterator`
used in the corresponding `connect()` or async_connect()` function.

[heading Examples]

A free function as a composed connect handler:

  void connect_handler(
      const boost::system::error_code& ec,
      boost::asio::ip::tcp::resolver::iterator iterator)
  {
    ...
  }

A composed connect handler function object:

  struct connect_handler
  {
    ...
    template <typename Iterator>
    void operator()(
        const boost::system::error_code& ec,
        Iterator iterator)
    {
      ...
    }
    ...
  };

A non-static class member function adapted to a composed connect handler using `bind()`:

  void my_class::connect_handler(
      const boost::system::error_code& ec,
      boost::asio::ip::tcp::resolver::iterator iterator)
  {
    ...
  }
  ...
  boost::asio::async_connect(...,
      boost::bind(&my_class::connect_handler,
        this, boost::asio::placeholders::error,
        boost::asio::placeholders::iterator));

[endsect]