ceph/src/boost/libs/asio/doc/requirements/ComposedConnectHandler.qbk

   1 [/
   2  / Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   3  /
   4  / Distributed under the Boost Software License, Version 1.0. (See accompanying
   5  / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6  /]
   7
   8 [section:ComposedConnectHandler Composed connect handler requirements]
   9
  10 A composed connect handler must meet the requirements for a [link
  11 boost_asio.reference.Handler handler]. A value `h` of a composed connect handler
  12 class should work correctly in the expression `h(ec, i)`, where `ec` is an
  13 lvalue of type `const error_code` and `i` is an lvalue of the type `Iterator`
  14 used in the corresponding `connect()` or async_connect()` function.
  15
  16 [heading Examples]
  17
  18 A free function as a composed connect handler:
  19
  20   void connect_handler(
  21       const boost::system::error_code& ec,
  22       boost::asio::ip::tcp::resolver::iterator iterator)
  23   {
  24     ...
  25   }
  26
  27 A composed connect handler function object:
  28
  29   struct connect_handler
  30   {
  31     ...
  32     template <typename Iterator>
  33     void operator()(
  34         const boost::system::error_code& ec,
  35         Iterator iterator)
  36     {
  37       ...
  38     }
  39     ...
  40   };
  41
  42 A non-static class member function adapted to a composed connect handler using `bind()`:
  43
  44   void my_class::connect_handler(
  45       const boost::system::error_code& ec,
  46       boost::asio::ip::tcp::resolver::iterator iterator)
  47   {
  48     ...
  49   }
  50   ...
  51   boost::asio::async_connect(...,
  52       boost::bind(&my_class::connect_handler,
  53         this, boost::asio::placeholders::error,
  54         boost::asio::placeholders::iterator));
  55
  56 [endsect]