EVOLUTION-MANAGER

Edit File: uses_executor.hpp

// // 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 BOOST_ASIO_USES_EXECUTOR_HPP #define BOOST_ASIO_USES_EXECUTOR_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #include <boost/asio/detail/type_traits.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { 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. BOOST_ASIO_CONSTEXPR executor_arg_t() BOOST_ASIO_NOEXCEPT { } }; /// A special value, similar to std::nothrow, used to disambiguate constructors /// that accept executor arguments. /** * See boost::asio::executor_arg_t and boost::asio::uses_executor * for more information. */ #if defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) constexpr executor_arg_t executor_arg; #elif defined(BOOST_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 } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_USES_EXECUTOR_HPP