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							- //
 - // uses_executor.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_USES_EXECUTOR_HPP
 - #define ASIO_USES_EXECUTOR_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/type_traits.hpp"
 - 
 - #include "asio/detail/push_options.hpp"
 - 
 - namespace asio {
 - 
 - /// A special type, similar to std::nothrow_t, used to disambiguate
 - /// constructors that accept executor arguments.
 - /**
 -  * The executor_arg_t struct is an empty structure type used as a unique type
 -  * to disambiguate constructor and function overloading. Specifically, some
 -  * types have constructors with executor_arg_t as the first argument,
 -  * immediately followed by an argument of a type that satisfies the Executor
 -  * type requirements.
 -  */
 - struct executor_arg_t
 - {
 -   /// Constructor.
 -   ASIO_CONSTEXPR executor_arg_t() ASIO_NOEXCEPT
 -   {
 -   }
 - };
 - 
 - /// A special value, similar to std::nothrow, used to disambiguate constructors
 - /// that accept executor arguments.
 - /**
 -  * See asio::executor_arg_t and asio::uses_executor
 -  * for more information.
 -  */
 - #if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION)
 - constexpr executor_arg_t executor_arg;
 - #elif defined(ASIO_MSVC)
 - __declspec(selectany) executor_arg_t executor_arg;
 - #endif
 - 
 - /// The uses_executor trait detects whether a type T has an associated executor
 - /// that is convertible from type Executor.
 - /**
 -  * Meets the BinaryTypeTrait requirements. The Asio library provides a
 -  * definition that is derived from false_type. A program may specialize this
 -  * template to derive from true_type for a user-defined type T that can be
 -  * constructed with an executor, where the first argument of a constructor has
 -  * type executor_arg_t and the second argument is convertible from type
 -  * Executor.
 -  */
 - template <typename T, typename Executor>
 - struct uses_executor : false_type {};
 - 
 - } // namespace asio
 - 
 - #include "asio/detail/pop_options.hpp"
 - 
 - #endif // ASIO_USES_EXECUTOR_HPP
 
 
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