// // traits/require_free.hpp // ~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2022 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_TRAITS_REQUIRE_FREE_HPP #define BOOST_ASIO_TRAITS_REQUIRE_FREE_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> #if defined(BOOST_ASIO_HAS_DECLTYPE) \ && defined(BOOST_ASIO_HAS_NOEXCEPT) \ && defined(BOOST_ASIO_HAS_WORKING_EXPRESSION_SFINAE) # define BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT 1 #endif // defined(BOOST_ASIO_HAS_DECLTYPE) // && defined(BOOST_ASIO_HAS_NOEXCEPT) // && defined(BOOST_ASIO_HAS_WORKING_EXPRESSION_SFINAE) #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace traits { template <typename T, typename Property, typename = void> struct require_free_default; template <typename T, typename Property, typename = void> struct require_free; } // namespace traits namespace detail { struct no_require_free { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = false); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false); }; #if defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) template <typename T, typename Property, typename = void> struct require_free_trait : no_require_free { }; template <typename T, typename Property> struct require_free_trait<T, Property, typename void_type< decltype(require(declval<T>(), declval<Property>())) >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); using result_type = decltype( require(declval<T>(), declval<Property>())); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = noexcept( require(declval<T>(), declval<Property>()))); }; #else // defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) template <typename T, typename Property, typename = void> struct require_free_trait : conditional< is_same<T, typename decay<T>::type>::value && is_same<Property, typename decay<Property>::type>::value, no_require_free, traits::require_free< typename decay<T>::type, typename decay<Property>::type> >::type { }; #endif // defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) } // namespace detail namespace traits { template <typename T, typename Property, typename> struct require_free_default : detail::require_free_trait<T, Property> { }; template <typename T, typename Property, typename> struct require_free : require_free_default<T, Property> { }; } // namespace traits } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_TRAITS_REQUIRE_FREE_HPP