--- /dev/null
+//
+// execution/relationship.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2020 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)
+ template <typename T>
+ BOOST_ASIO_STATIC_CONSTEXPR(bool,
+ is_applicable_property_v = is_executor<T>::value
+ || is_sender<T>::value || is_scheduler<T>::value);
+#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)
+ {
+ }
+
+#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
+ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
+ template <typename T>
+ static BOOST_ASIO_CONSTEXPR
+ typename traits::query_static_constexpr_member<
+ T, relationship_t>::result_type
+ static_query()
+ BOOST_ASIO_NOEXCEPT_IF((
+ traits::query_static_constexpr_member<
+ T, relationship_t
+ >::is_noexcept))
+ {
+ return traits::query_static_constexpr_member<
+ T, relationship_t>::value();
+ }
+
+ template <typename T>
+ static BOOST_ASIO_CONSTEXPR
+ typename traits::static_query<T, fork_t>::result_type
+ static_query(
+ typename enable_if<
+ !traits::query_static_constexpr_member<
+ T, relationship_t>::is_valid
+ && !traits::query_member<T, relationship_t>::is_valid
+ && 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<
+ !traits::query_static_constexpr_member<
+ T, relationship_t>::is_valid
+ && !traits::query_member<T, relationship_t>::is_valid
+ && !traits::static_query<T, fork_t>::is_valid
+ && 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
+ && 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)
+ template <typename T>
+ BOOST_ASIO_STATIC_CONSTEXPR(bool,
+ is_applicable_property_v = is_executor<T>::value
+ || is_sender<T>::value || is_scheduler<T>::value);
+#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()
+ {
+ }
+
+#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
+ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
+ template <typename T>
+ static BOOST_ASIO_CONSTEXPR
+ typename traits::query_static_constexpr_member<T, fork_t>::result_type
+ static_query()
+ BOOST_ASIO_NOEXCEPT_IF((
+ traits::query_static_constexpr_member<T, fork_t>::is_noexcept))
+ {
+ return traits::query_static_constexpr_member<T, fork_t>::value();
+ }
+
+ template <typename T>
+ static BOOST_ASIO_CONSTEXPR fork_t static_query(
+ typename enable_if<
+ !traits::query_static_constexpr_member<T, fork_t>::is_valid
+ && !traits::query_member<T, fork_t>::is_valid
+ && !traits::query_free<T, fork_t>::is_valid
+ && !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)
+ template <typename T>
+ BOOST_ASIO_STATIC_CONSTEXPR(bool,
+ is_applicable_property_v = is_executor<T>::value
+ || is_sender<T>::value || is_scheduler<T>::value);
+#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()
+ {
+ }
+
+#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
+ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
+ template <typename T>
+ static BOOST_ASIO_CONSTEXPR
+ typename traits::query_static_constexpr_member<T, continuation_t>::result_type
+ static_query()
+ BOOST_ASIO_NOEXCEPT_IF((
+ traits::query_static_constexpr_member<T, continuation_t>::is_noexcept))
+ {
+ return traits::query_static_constexpr_member<T, continuation_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
+ || execution::is_sender<T>::value
+ || execution::is_scheduler<T>::value>
+{
+};
+
+template <typename T>
+struct is_applicable_property<T, execution::relationship_t::fork_t>
+ : integral_constant<bool,
+ execution::is_executor<T>::value
+ || execution::is_sender<T>::value
+ || execution::is_scheduler<T>::value>
+{
+};
+
+template <typename T>
+struct is_applicable_property<T, execution::relationship_t::continuation_t>
+ : integral_constant<bool,
+ execution::is_executor<T>::value
+ || execution::is_sender<T>::value
+ || execution::is_scheduler<T>::value>
+{
+};
+
+#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<
+ traits::query_static_constexpr_member<T,
+ execution::relationship_t>::is_valid
+ >::type>
+{
+ BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true);
+ BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true);
+
+ typedef typename traits::query_static_constexpr_member<T,
+ execution::relationship_t>::result_type result_type;
+
+ static BOOST_ASIO_CONSTEXPR result_type value()
+ {
+ return traits::query_static_constexpr_member<T,
+ execution::relationship_t>::value();
+ }
+};
+
+template <typename T>
+struct static_query<T, execution::relationship_t,
+ typename enable_if<
+ !traits::query_static_constexpr_member<T,
+ execution::relationship_t>::is_valid
+ && !traits::query_member<T,
+ execution::relationship_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<
+ !traits::query_static_constexpr_member<T,
+ execution::relationship_t>::is_valid
+ && !traits::query_member<T,
+ execution::relationship_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<
+ traits::query_static_constexpr_member<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::query_static_constexpr_member<T,
+ execution::relationship_t::fork_t>::result_type result_type;
+
+ static BOOST_ASIO_CONSTEXPR result_type value()
+ {
+ return traits::query_static_constexpr_member<T,
+ execution::relationship_t::fork_t>::value();
+ }
+};
+
+template <typename T>
+struct static_query<T, execution::relationship_t::fork_t,
+ typename enable_if<
+ !traits::query_static_constexpr_member<T,
+ execution::relationship_t::fork_t>::is_valid
+ && !traits::query_member<T,
+ execution::relationship_t::fork_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<
+ traits::query_static_constexpr_member<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::query_static_constexpr_member<T,
+ execution::relationship_t::continuation_t>::result_type result_type;
+
+ static BOOST_ASIO_CONSTEXPR result_type value()
+ {
+ return traits::query_static_constexpr_member<T,
+ execution::relationship_t::continuation_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
projects / ceph.git / blobdiff