boost/asio/execution/relationship.hpp
// // execution/relationship.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_EXECUTION_RELATIONSHIP_HPP #define BOOST_ASIO_EXECUTION_RELATIONSHIP_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/execution/executor.hpp> #include <boost/asio/execution/scheduler.hpp> #include <boost/asio/execution/sender.hpp> #include <boost/asio/is_applicable_property.hpp> #include <boost/asio/query.hpp> #include <boost/asio/traits/query_free.hpp> #include <boost/asio/traits/query_member.hpp> #include <boost/asio/traits/query_static_constexpr_member.hpp> #include <boost/asio/traits/static_query.hpp> #include <boost/asio/traits/static_require.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { #if defined(GENERATING_DOCUMENTATION) namespace execution { /// A property to describe whether submitted tasks represent continuations of /// the calling context. struct relationship_t { /// The relationship_t property applies to executors, senders, and schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The top-level relationship_t property cannot be required. static constexpr bool is_requirable = false; /// The top-level relationship_t property cannot be preferred. static constexpr bool is_preferable = false; /// The type returned by queries against an @c any_executor. typedef relationship_t polymorphic_query_result_type; /// A sub-property that indicates that the executor does not represent a /// continuation of the calling context. struct fork_t { /// The relationship_t::fork_t property applies to executors, senders, and /// schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The relationship_t::fork_t property can be required. static constexpr bool is_requirable = true; /// The relationship_t::fork_t property can be preferred. static constexpr bool is_preferable = true; /// The type returned by queries against an @c any_executor. typedef relationship_t polymorphic_query_result_type; /// Default constructor. constexpr fork_t(); /// Get the value associated with a property object. /** * @returns fork_t(); */ static constexpr relationship_t value(); }; /// A sub-property that indicates that the executor represents a continuation /// of the calling context. struct continuation_t { /// The relationship_t::continuation_t property applies to executors, /// senders, and schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The relationship_t::continuation_t property can be required. static constexpr bool is_requirable = true; /// The relationship_t::continuation_t property can be preferred. static constexpr bool is_preferable = true; /// The type returned by queries against an @c any_executor. typedef relationship_t polymorphic_query_result_type; /// Default constructor. constexpr continuation_t(); /// Get the value associated with a property object. /** * @returns continuation_t(); */ static constexpr relationship_t value(); }; /// A special value used for accessing the relationship_t::fork_t property. static constexpr fork_t fork; /// A special value used for accessing the relationship_t::continuation_t /// property. static constexpr continuation_t continuation; /// Default constructor. constexpr relationship_t(); /// Construct from a sub-property value. constexpr relationship_t(fork_t); /// Construct from a sub-property value. constexpr relationship_t(continuation_t); /// Compare property values for equality. friend constexpr bool operator==( const relationship_t& a, const relationship_t& b) noexcept; /// Compare property values for inequality. friend constexpr bool operator!=( const relationship_t& a, const relationship_t& b) noexcept; }; /// A special value used for accessing the relationship_t property. constexpr relationship_t relationship; } // namespace execution #else // defined(GENERATING_DOCUMENTATION) namespace execution { namespace detail { namespace relationship { template <int I> struct fork_t; template <int I> struct continuation_t; } // namespace relationship template <int I = 0> struct relationship_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) # if defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value)); # else // defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value )); # endif // defined(BOOST_ASIO_NO_DEPRECATED) #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = false); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = false); typedef relationship_t polymorphic_query_result_type; typedef detail::relationship::fork_t<I> fork_t; typedef detail::relationship::continuation_t<I> continuation_t; BOOST_ASIO_CONSTEXPR relationship_t() : value_(-1) { } BOOST_ASIO_CONSTEXPR relationship_t(fork_t) : value_(0) { } BOOST_ASIO_CONSTEXPR relationship_t(continuation_t) : value_(1) { } template <typename T> struct proxy { #if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) struct type { template <typename P> auto query(BOOST_ASIO_MOVE_ARG(P) p) const noexcept( noexcept( declval<typename conditional<true, T, P>::type>().query( BOOST_ASIO_MOVE_CAST(P)(p)) ) ) -> decltype( declval<typename conditional<true, T, P>::type>().query( BOOST_ASIO_MOVE_CAST(P)(p)) ); }; #else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) typedef T type; #endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) }; template <typename T> struct static_proxy { #if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) struct type { template <typename P> static constexpr auto query(BOOST_ASIO_MOVE_ARG(P) p) noexcept( noexcept( conditional<true, T, P>::type::query(BOOST_ASIO_MOVE_CAST(P)(p)) ) ) -> decltype( conditional<true, T, P>::type::query(BOOST_ASIO_MOVE_CAST(P)(p)) ) { return T::query(BOOST_ASIO_MOVE_CAST(P)(p)); } }; #else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) typedef T type; #endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) }; template <typename T> struct query_member : traits::query_member<typename proxy<T>::type, relationship_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename static_proxy<T>::type, relationship_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR typename traits::static_query<T, fork_t>::result_type static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< traits::static_query<T, fork_t>::is_valid >::type* = 0) BOOST_ASIO_NOEXCEPT { return traits::static_query<T, fork_t>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR typename traits::static_query<T, continuation_t>::result_type static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< !traits::static_query<T, fork_t>::is_valid >::type* = 0, typename enable_if< traits::static_query<T, continuation_t>::is_valid >::type* = 0) BOOST_ASIO_NOEXCEPT { return traits::static_query<T, continuation_t>::value(); } template <typename E, typename T = decltype(relationship_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = relationship_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) friend BOOST_ASIO_CONSTEXPR bool operator==( const relationship_t& a, const relationship_t& b) { return a.value_ == b.value_; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const relationship_t& a, const relationship_t& b) { return a.value_ != b.value_; } struct convertible_from_relationship_t { BOOST_ASIO_CONSTEXPR convertible_from_relationship_t(relationship_t) { } }; template <typename Executor> friend BOOST_ASIO_CONSTEXPR relationship_t query( const Executor& ex, convertible_from_relationship_t, typename enable_if< can_query<const Executor&, fork_t>::value >::type* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(BOOST_ASIO_MSVC) // Visual C++ wants the type to be qualified. BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, relationship_t<>::fork_t>::value)) #else // defined(BOOST_ASIO_MSVC) BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, fork_t>::value)) #endif // defined(BOOST_ASIO_MSVC) #endif // !defined(__clang__) { return boost::asio::query(ex, fork_t()); } template <typename Executor> friend BOOST_ASIO_CONSTEXPR relationship_t query( const Executor& ex, convertible_from_relationship_t, typename enable_if< !can_query<const Executor&, fork_t>::value >::type* = 0, typename enable_if< can_query<const Executor&, continuation_t>::value >::type* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(BOOST_ASIO_MSVC) // Visual C++ wants the type to be qualified. BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, relationship_t<>::continuation_t>::value)) #else // defined(BOOST_ASIO_MSVC) BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, continuation_t>::value)) #endif // defined(BOOST_ASIO_MSVC) #endif // !defined(__clang__) { return boost::asio::query(ex, continuation_t()); } BOOST_ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(fork_t, fork); BOOST_ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(continuation_t, continuation); #if !defined(BOOST_ASIO_HAS_CONSTEXPR) static const relationship_t instance; #endif // !defined(BOOST_ASIO_HAS_CONSTEXPR) private: int value_; }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T relationship_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) #if !defined(BOOST_ASIO_HAS_CONSTEXPR) template <int I> const relationship_t<I> relationship_t<I>::instance; #endif template <int I> const typename relationship_t<I>::fork_t relationship_t<I>::fork; template <int I> const typename relationship_t<I>::continuation_t relationship_t<I>::continuation; namespace relationship { template <int I = 0> struct fork_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) # if defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value)); # else // defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value )); # endif // defined(BOOST_ASIO_NO_DEPRECATED) #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = true); typedef relationship_t<I> polymorphic_query_result_type; BOOST_ASIO_CONSTEXPR fork_t() { } template <typename T> struct query_member : traits::query_member< typename relationship_t<I>::template proxy<T>::type, fork_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename relationship_t<I>::template static_proxy<T>::type, fork_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR fork_t static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< !traits::query_free<T, fork_t>::is_valid >::type* = 0, typename enable_if< !can_query<T, continuation_t<I> >::value >::type* = 0) BOOST_ASIO_NOEXCEPT { return fork_t(); } template <typename E, typename T = decltype(fork_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = fork_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static BOOST_ASIO_CONSTEXPR relationship_t<I> value() { return fork_t(); } friend BOOST_ASIO_CONSTEXPR bool operator==( const fork_t&, const fork_t&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const fork_t&, const fork_t&) { return false; } }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T fork_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I = 0> struct continuation_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) # if defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value)); # else // defined(BOOST_ASIO_NO_DEPRECATED) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value )); # endif // defined(BOOST_ASIO_NO_DEPRECATED) #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = true); typedef relationship_t<I> polymorphic_query_result_type; BOOST_ASIO_CONSTEXPR continuation_t() { } template <typename T> struct query_member : traits::query_member< typename relationship_t<I>::template proxy<T>::type, continuation_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename relationship_t<I>::template static_proxy<T>::type, continuation_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename E, typename T = decltype(continuation_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = continuation_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static BOOST_ASIO_CONSTEXPR relationship_t<I> value() { return continuation_t(); } friend BOOST_ASIO_CONSTEXPR bool operator==( const continuation_t&, const continuation_t&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const continuation_t&, const continuation_t&) { return false; } }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T continuation_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) } // namespace relationship } // namespace detail typedef detail::relationship_t<> relationship_t; #if defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) constexpr relationship_t relationship; #else // defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) namespace { static const relationship_t& relationship = relationship_t::instance; } #endif } // namespace execution #if !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> struct is_applicable_property<T, execution::relationship_t> : integral_constant<bool, execution::is_executor<T>::value #if !defined(BOOST_ASIO_NO_DEPRECATED) || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value #endif // !defined(BOOST_ASIO_NO_DEPRECATED) > { }; template <typename T> struct is_applicable_property<T, execution::relationship_t::fork_t> : integral_constant<bool, execution::is_executor<T>::value #if !defined(BOOST_ASIO_NO_DEPRECATED) || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value #endif // !defined(BOOST_ASIO_NO_DEPRECATED) > { }; template <typename T> struct is_applicable_property<T, execution::relationship_t::continuation_t> : integral_constant<bool, execution::is_executor<T>::value #if !defined(BOOST_ASIO_NO_DEPRECATED) || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value #endif // !defined(BOOST_ASIO_NO_DEPRECATED) > { }; #endif // !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) namespace traits { #if !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) template <typename T> struct query_free_default<T, execution::relationship_t, typename enable_if< can_query<T, execution::relationship_t::fork_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<T, execution::relationship_t::fork_t>::value)); typedef execution::relationship_t result_type; }; template <typename T> struct query_free_default<T, execution::relationship_t, typename enable_if< !can_query<T, execution::relationship_t::fork_t>::value && can_query<T, execution::relationship_t::continuation_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<T, execution::relationship_t::continuation_t>::value)); typedef execution::relationship_t result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ || !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> struct static_query<T, execution::relationship_t, typename enable_if< execution::detail::relationship_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::relationship_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::relationship_t<0>:: query_static_constexpr_member<T>::value(); } }; template <typename T> struct static_query<T, execution::relationship_t, typename enable_if< !execution::detail::relationship_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::relationship_t<0>:: query_member<T>::is_valid && traits::static_query<T, execution::relationship_t::fork_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename traits::static_query<T, execution::relationship_t::fork_t>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return traits::static_query<T, execution::relationship_t::fork_t>::value(); } }; template <typename T> struct static_query<T, execution::relationship_t, typename enable_if< !execution::detail::relationship_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::relationship_t<0>:: query_member<T>::is_valid && !traits::static_query<T, execution::relationship_t::fork_t>::is_valid && traits::static_query<T, execution::relationship_t::continuation_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename traits::static_query<T, execution::relationship_t::continuation_t>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return traits::static_query<T, execution::relationship_t::continuation_t>::value(); } }; template <typename T> struct static_query<T, execution::relationship_t::fork_t, typename enable_if< execution::detail::relationship::fork_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::relationship::fork_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::relationship::fork_t<0>:: query_static_constexpr_member<T>::value(); } }; template <typename T> struct static_query<T, execution::relationship_t::fork_t, typename enable_if< !execution::detail::relationship::fork_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::relationship::fork_t<0>:: query_member<T>::is_valid && !traits::query_free<T, execution::relationship_t::fork_t>::is_valid && !can_query<T, execution::relationship_t::continuation_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::relationship_t::fork_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return result_type(); } }; template <typename T> struct static_query<T, execution::relationship_t::continuation_t, typename enable_if< execution::detail::relationship::continuation_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::relationship::continuation_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::relationship::continuation_t<0>:: query_static_constexpr_member<T>::value(); } }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // || !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) #if !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT) template <typename T> struct static_require<T, execution::relationship_t::fork_t, typename enable_if< static_query<T, execution::relationship_t::fork_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = (is_same<typename static_query<T, execution::relationship_t::fork_t>::result_type, execution::relationship_t::fork_t>::value)); }; template <typename T> struct static_require<T, execution::relationship_t::continuation_t, typename enable_if< static_query<T, execution::relationship_t::continuation_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = (is_same<typename static_query<T, execution::relationship_t::continuation_t>::result_type, execution::relationship_t::continuation_t>::value)); }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT) } // namespace traits #endif // defined(GENERATING_DOCUMENTATION) } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_EXECUTION_RELATIONSHIP_HPP