2 // handler_invoke_hook.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~
5 // Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com)
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
11 #ifndef BOOST_ASIO_HANDLER_INVOKE_HOOK_HPP
12 #define BOOST_ASIO_HANDLER_INVOKE_HOOK_HPP
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
18 #include <boost/asio/detail/config.hpp>
20 #include <boost/asio/detail/push_options.hpp>
25 /// Default invoke function for handlers.
27 * Completion handlers for asynchronous operations are invoked by the
28 * io_service associated with the corresponding object (e.g. a socket or
29 * deadline_timer). Certain guarantees are made on when the handler may be
30 * invoked, in particular that a handler can only be invoked from a thread that
31 * is currently calling @c run() on the corresponding io_service object.
32 * Handlers may subsequently be invoked through other objects (such as
33 * io_service::strand objects) that provide additional guarantees.
35 * When asynchronous operations are composed from other asynchronous
36 * operations, all intermediate handlers should be invoked using the same
37 * method as the final handler. This is required to ensure that user-defined
38 * objects are not accessed in a way that may violate the guarantees. This
39 * hooking function ensures that the invoked method used for the final handler
40 * is accessible at each intermediate step.
42 * Implement asio_handler_invoke for your own handlers to specify a custom
43 * invocation strategy.
45 * This default implementation is simply:
54 * template <typename Function>
55 * void asio_handler_invoke(Function function, my_handler* context)
57 * context->strand_.dispatch(function);
61 template <typename Function>
62 inline void asio_handler_invoke(Function function, ...)
70 #include <boost/asio/detail/pop_options.hpp>
72 #endif // BOOST_ASIO_HANDLER_INVOKE_HOOK_HPP