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- //
- // handler_invoke_hook.hpp
- // ~~~~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2015 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)
- //
-
- #ifndef ASIO_HANDLER_INVOKE_HOOK_HPP
- #define ASIO_HANDLER_INVOKE_HOOK_HPP
-
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
-
- #include "asio/detail/config.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
-
- /** @defgroup asio_handler_invoke asio::asio_handler_invoke
- *
- * @brief Default invoke function for handlers.
- *
- * Completion handlers for asynchronous operations are invoked by the
- * io_context associated with the corresponding object (e.g. a socket or
- * deadline_timer). Certain guarantees are made on when the handler may be
- * invoked, in particular that a handler can only be invoked from a thread that
- * is currently calling @c run() on the corresponding io_context object.
- * Handlers may subsequently be invoked through other objects (such as
- * io_context::strand objects) that provide additional guarantees.
- *
- * When asynchronous operations are composed from other asynchronous
- * operations, all intermediate handlers should be invoked using the same
- * method as the final handler. This is required to ensure that user-defined
- * objects are not accessed in a way that may violate the guarantees. This
- * hooking function ensures that the invoked method used for the final handler
- * is accessible at each intermediate step.
- *
- * Implement asio_handler_invoke for your own handlers to specify a custom
- * invocation strategy.
- *
- * This default implementation invokes the function object like so:
- * @code function(); @endcode
- * If necessary, the default implementation makes a copy of the function object
- * so that the non-const operator() can be used.
- *
- * @par Example
- * @code
- * class my_handler;
- *
- * template <typename Function>
- * void asio_handler_invoke(Function function, my_handler* context)
- * {
- * context->strand_.dispatch(function);
- * }
- * @endcode
- */
- /*@{*/
-
- /// Default handler invocation hook used for non-const function objects.
- template <typename Function>
- inline void asio_handler_invoke(Function& function, ...)
- {
- function();
- }
-
- /// Default handler invocation hook used for const function objects.
- template <typename Function>
- inline void asio_handler_invoke(const Function& function, ...)
- {
- Function tmp(function);
- tmp();
- }
-
- /*@}*/
-
- } // namespace asio
-
- #include "asio/detail/pop_options.hpp"
-
- #endif // ASIO_HANDLER_INVOKE_HOOK_HPP
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