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							- //
 - // compose.hpp
 - // ~~~~~~~~~~~
 - //
 - // Copyright (c) 2003-2019 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_COMPOSE_HPP
 - #define ASIO_COMPOSE_HPP
 - 
 - #if defined(_MSC_VER) && (_MSC_VER >= 1200)
 - # pragma once
 - #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
 - 
 - #include "asio/detail/config.hpp"
 - #include "asio/async_result.hpp"
 - 
 - #include "asio/detail/push_options.hpp"
 - 
 - namespace asio {
 - 
 - #if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
 -   || defined(GENERATING_DOCUMENTATION)
 - 
 - /// Launch an asynchronous operation with a stateful implementation.
 - /**
 -  * The async_compose function simplifies the implementation of composed
 -  * asynchronous operations automatically wrapping a stateful function object
 -  * with a conforming intermediate completion handler.
 -  *
 -  * @param implementation A function object that contains the implementation of
 -  * the composed asynchronous operation. The first argument to the function
 -  * object is a non-const reference to the enclosing intermediate completion
 -  * handler. The remaining arguments are any arguments that originate from the
 -  * completion handlers of any asynchronous operations performed by the
 -  * implementation.
 - 
 -  * @param token The completion token.
 -  *
 -  * @param io_objects_or_executors Zero or more I/O objects or I/O executors for
 -  * which outstanding work must be maintained.
 -  *
 -  * @par Example:
 -  *
 -  * @code struct async_echo_implementation
 -  * {
 -  *   tcp::socket& socket_;
 -  *   asio::mutable_buffer buffer_;
 -  *   enum { starting, reading, writing } state_;
 -  *
 -  *   template <typename Self>
 -  *   void operator()(Self& self,
 -  *       asio::error_code error = {},
 -  *       std::size_t n = 0)
 -  *   {
 -  *     switch (state_)
 -  *     {
 -  *     case starting:
 -  *       state_ = reading;
 -  *       socket_.async_read_some(
 -  *           buffer_, std::move(self));
 -  *       break;
 -  *     case reading:
 -  *       if (error)
 -  *       {
 -  *         self.complete(error, 0);
 -  *       }
 -  *       else
 -  *       {
 -  *         state_ = writing;
 -  *         asio::async_write(socket_, buffer_,
 -  *             asio::transfer_exactly(n),
 -  *             std::move(self));
 -  *       }
 -  *       break;
 -  *     case writing:
 -  *       self.complete(error, n);
 -  *       break;
 -  *     }
 -  *   }
 -  * };
 -  *
 -  * template <typename CompletionToken>
 -  * auto async_echo(tcp::socket& socket,
 -  *     asio::mutable_buffer buffer,
 -  *     CompletionToken&& token) ->
 -  *   typename asio::async_result<
 -  *     typename std::decay<CompletionToken>::type,
 -  *       void(asio::error_code, std::size_t)>::return_type
 -  * {
 -  *   return asio::async_compose<CompletionToken,
 -  *     void(asio::error_code, std::size_t)>(
 -  *       async_echo_implementation{socket, buffer,
 -  *         async_echo_implementation::starting},
 -  *       token, socket);
 -  * } @endcode
 -  */
 - template <typename CompletionToken, typename Signature,
 -     typename Implementation, typename... IoObjectsOrExecutors>
 - ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature)
 - async_compose(ASIO_MOVE_ARG(Implementation) implementation,
 -     ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token,
 -     ASIO_MOVE_ARG(IoObjectsOrExecutors)... io_objects_or_executors);
 - 
 - #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
 -       //   || defined(GENERATING_DOCUMENTATION)
 - 
 - template <typename CompletionToken, typename Signature, typename Implementation>
 - ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature)
 - async_compose(ASIO_MOVE_ARG(Implementation) implementation,
 -     ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token);
 - 
 - #define ASIO_PRIVATE_ASYNC_COMPOSE_DEF(n) \
 -   template <typename CompletionToken, typename Signature, \
 -       typename Implementation, ASIO_VARIADIC_TPARAMS(n)> \
 -   ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature) \
 -   async_compose(ASIO_MOVE_ARG(Implementation) implementation, \
 -       ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, \
 -       ASIO_VARIADIC_MOVE_PARAMS(n));
 -   /**/
 -   ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_COMPOSE_DEF)
 - #undef ASIO_PRIVATE_ASYNC_COMPOSE_DEF
 - 
 - #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
 -        //   || defined(GENERATING_DOCUMENTATION)
 - 
 - } // namespace asio
 - 
 - #include "asio/detail/pop_options.hpp"
 - 
 - #include "asio/impl/compose.hpp"
 - 
 - #endif // ASIO_COMPOSE_HPP
 
 
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