739 lines
21 KiB
C++
Executable File
739 lines
21 KiB
C++
Executable File
//
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// prefer.hpp
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// ~~~~~~~~~~
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//
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// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef BOOST_ASIO_PREFER_HPP
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#define BOOST_ASIO_PREFER_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include <boost/asio/detail/config.hpp>
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#include <boost/asio/detail/type_traits.hpp>
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#include <boost/asio/is_applicable_property.hpp>
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#include <boost/asio/traits/prefer_free.hpp>
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#include <boost/asio/traits/prefer_member.hpp>
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#include <boost/asio/traits/require_free.hpp>
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#include <boost/asio/traits/require_member.hpp>
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#include <boost/asio/traits/static_require.hpp>
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#include <boost/asio/detail/push_options.hpp>
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#if defined(GENERATING_DOCUMENTATION)
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namespace boost {
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namespace asio {
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/// A customisation point that attempts to apply a property to an object.
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/**
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* The name <tt>prefer</tt> denotes a customisation point object. The
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* expression <tt>boost::asio::prefer(E, P0, Pn...)</tt> for some subexpressions
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* <tt>E</tt> and <tt>P0</tt>, and where <tt>Pn...</tt> represents <tt>N</tt>
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* subexpressions (where <tt>N</tt> is 0 or more, and with types <tt>T =
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* decay_t<decltype(E)></tt> and <tt>Prop0 = decay_t<decltype(P0)></tt>) is
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* expression-equivalent to:
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*
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* @li If <tt>is_applicable_property_v<T, Prop0> && Prop0::is_preferable</tt> is
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* not a well-formed constant expression with value <tt>true</tt>,
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* <tt>boost::asio::prefer(E, P0, Pn...)</tt> is ill-formed.
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*
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* @li Otherwise, <tt>E</tt> if <tt>N == 0</tt> and the expression
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* <tt>Prop0::template static_query_v<T> == Prop0::value()</tt> is a
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* well-formed constant expression with value <tt>true</tt>.
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*
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* @li Otherwise, <tt>(E).require(P0)</tt> if <tt>N == 0</tt> and the expression
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* <tt>(E).require(P0)</tt> is a valid expression.
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*
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* @li Otherwise, <tt>require(E, P0)</tt> if <tt>N == 0</tt> and the expression
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* <tt>require(E, P0)</tt> is a valid expression with overload resolution
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* performed in a context that does not include the declaration of the
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* <tt>require</tt> customization point object.
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*
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* @li Otherwise, <tt>(E).prefer(P0)</tt> if <tt>N == 0</tt> and the expression
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* <tt>(E).prefer(P0)</tt> is a valid expression.
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*
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* @li Otherwise, <tt>prefer(E, P0)</tt> if <tt>N == 0</tt> and the expression
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* <tt>prefer(E, P0)</tt> is a valid expression with overload resolution
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* performed in a context that does not include the declaration of the
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* <tt>prefer</tt> customization point object.
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*
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* @li Otherwise, <tt>E</tt> if <tt>N == 0</tt>.
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*
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* @li Otherwise,
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* <tt>boost::asio::prefer(boost::asio::prefer(E, P0), Pn...)</tt>
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* if <tt>N > 0</tt> and the expression
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* <tt>boost::asio::prefer(boost::asio::prefer(E, P0), Pn...)</tt>
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* is a valid expression.
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*
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* @li Otherwise, <tt>boost::asio::prefer(E, P0, Pn...)</tt> is ill-formed.
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*/
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inline constexpr unspecified prefer = unspecified;
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/// A type trait that determines whether a @c prefer expression is well-formed.
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/**
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* Class template @c can_prefer is a trait that is derived from
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* @c true_type if the expression <tt>boost::asio::prefer(std::declval<T>(),
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* std::declval<Properties>()...)</tt> is well formed; otherwise @c false_type.
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*/
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template <typename T, typename... Properties>
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struct can_prefer :
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integral_constant<bool, automatically_determined>
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{
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};
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/// A type trait that determines whether a @c prefer expression will not throw.
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/**
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* Class template @c is_nothrow_prefer is a trait that is derived from
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* @c true_type if the expression <tt>boost::asio::prefer(std::declval<T>(),
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* std::declval<Properties>()...)</tt> is @c noexcept; otherwise @c false_type.
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*/
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template <typename T, typename... Properties>
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struct is_nothrow_prefer :
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integral_constant<bool, automatically_determined>
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{
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};
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/// A type trait that determines the result type of a @c prefer expression.
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/**
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* Class template @c prefer_result is a trait that determines the result
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* type of the expression <tt>boost::asio::prefer(std::declval<T>(),
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* std::declval<Properties>()...)</tt>.
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*/
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template <typename T, typename... Properties>
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struct prefer_result
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{
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/// The result of the @c prefer expression.
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typedef automatically_determined type;
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};
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} // namespace asio
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} // namespace boost
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#else // defined(GENERATING_DOCUMENTATION)
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namespace boost_asio_prefer_fn {
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using boost::asio::conditional;
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using boost::asio::decay;
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using boost::asio::declval;
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using boost::asio::enable_if;
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using boost::asio::is_applicable_property;
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using boost::asio::traits::prefer_free;
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using boost::asio::traits::prefer_member;
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using boost::asio::traits::require_free;
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using boost::asio::traits::require_member;
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using boost::asio::traits::static_require;
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void prefer();
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void require();
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enum overload_type
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{
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identity,
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call_require_member,
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call_require_free,
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call_prefer_member,
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call_prefer_free,
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two_props,
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n_props,
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ill_formed
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};
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template <typename Impl, typename T, typename Properties,
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typename = void, typename = void, typename = void, typename = void,
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typename = void, typename = void, typename = void>
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struct call_traits
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
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BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
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typedef void result_type;
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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static_require<T, Property>::is_valid
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>::type>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = identity);
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BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true);
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#if defined(BOOST_ASIO_HAS_MOVE)
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typedef BOOST_ASIO_MOVE_ARG(T) result_type;
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#else // defined(BOOST_ASIO_HAS_MOVE)
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typedef BOOST_ASIO_MOVE_ARG(typename decay<T>::type) result_type;
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#endif // defined(BOOST_ASIO_HAS_MOVE)
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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!static_require<T, Property>::is_valid
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>::type,
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typename enable_if<
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require_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type> :
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require_member<typename Impl::template proxy<T>::type, Property>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_require_member);
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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!static_require<T, Property>::is_valid
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>::type,
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typename enable_if<
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!require_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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require_free<T, Property>::is_valid
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>::type> :
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require_free<T, Property>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_require_free);
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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!static_require<T, Property>::is_valid
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>::type,
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typename enable_if<
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!require_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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!require_free<T, Property>::is_valid
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>::type,
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typename enable_if<
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prefer_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type> :
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prefer_member<typename Impl::template proxy<T>::type, Property>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_prefer_member);
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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!static_require<T, Property>::is_valid
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>::type,
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typename enable_if<
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!require_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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!require_free<T, Property>::is_valid
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>::type,
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typename enable_if<
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!prefer_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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prefer_free<T, Property>::is_valid
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>::type> :
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prefer_free<T, Property>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_prefer_free);
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};
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template <typename Impl, typename T, typename Property>
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struct call_traits<Impl, T, void(Property),
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typename enable_if<
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is_applicable_property<
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typename decay<T>::type,
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typename decay<Property>::type
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>::value
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>::type,
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typename enable_if<
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decay<Property>::type::is_preferable
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>::type,
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typename enable_if<
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!static_require<T, Property>::is_valid
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>::type,
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typename enable_if<
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!require_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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!require_free<T, Property>::is_valid
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>::type,
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typename enable_if<
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!prefer_member<typename Impl::template proxy<T>::type, Property>::is_valid
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>::type,
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typename enable_if<
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!prefer_free<T, Property>::is_valid
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>::type>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = identity);
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BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true);
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#if defined(BOOST_ASIO_HAS_MOVE)
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typedef BOOST_ASIO_MOVE_ARG(T) result_type;
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#else // defined(BOOST_ASIO_HAS_MOVE)
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typedef BOOST_ASIO_MOVE_ARG(typename decay<T>::type) result_type;
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#endif // defined(BOOST_ASIO_HAS_MOVE)
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};
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template <typename Impl, typename T, typename P0, typename P1>
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struct call_traits<Impl, T, void(P0, P1),
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typename enable_if<
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call_traits<Impl, T, void(P0)>::overload != ill_formed
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>::type,
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typename enable_if<
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call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1)
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>::overload != ill_formed
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>::type>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = two_props);
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BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept =
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(
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call_traits<Impl, T, void(P0)>::is_noexcept
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&&
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call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1)
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>::is_noexcept
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));
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typedef typename decay<
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typename call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1)
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>::result_type
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>::type result_type;
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};
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template <typename Impl, typename T, typename P0,
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typename P1, typename BOOST_ASIO_ELLIPSIS PN>
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struct call_traits<Impl, T, void(P0, P1, PN BOOST_ASIO_ELLIPSIS),
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typename enable_if<
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call_traits<Impl, T, void(P0)>::overload != ill_formed
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>::type,
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typename enable_if<
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call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1, PN BOOST_ASIO_ELLIPSIS)
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>::overload != ill_formed
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>::type>
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{
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BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = n_props);
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BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept =
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(
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call_traits<Impl, T, void(P0)>::is_noexcept
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&&
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call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1, PN BOOST_ASIO_ELLIPSIS)
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>::is_noexcept
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));
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typedef typename decay<
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typename call_traits<
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Impl,
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typename call_traits<Impl, T, void(P0)>::result_type,
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void(P1, PN BOOST_ASIO_ELLIPSIS)
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>::result_type
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>::type result_type;
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};
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struct impl
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{
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template <typename T>
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struct proxy
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{
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#if defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) \
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&& defined(BOOST_ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
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struct type
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{
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template <typename P>
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auto require(BOOST_ASIO_MOVE_ARG(P) p)
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noexcept(
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noexcept(
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declval<typename conditional<true, T, P>::type>().require(
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BOOST_ASIO_MOVE_CAST(P)(p))
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)
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)
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-> decltype(
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declval<typename conditional<true, T, P>::type>().require(
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BOOST_ASIO_MOVE_CAST(P)(p))
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);
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template <typename P>
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auto prefer(BOOST_ASIO_MOVE_ARG(P) p)
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noexcept(
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noexcept(
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declval<typename conditional<true, T, P>::type>().prefer(
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BOOST_ASIO_MOVE_CAST(P)(p))
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)
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)
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-> decltype(
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declval<typename conditional<true, T, P>::type>().prefer(
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BOOST_ASIO_MOVE_CAST(P)(p))
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);
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};
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#else // defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT)
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// && defined(BOOST_ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
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typedef T type;
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#endif // defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT)
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// && defined(BOOST_ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
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};
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template <typename T, typename Property>
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BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
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call_traits<impl, T, void(Property)>::overload == identity,
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typename call_traits<impl, T, void(Property)>::result_type
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>::type
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operator()(
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BOOST_ASIO_MOVE_ARG(T) t,
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BOOST_ASIO_MOVE_ARG(Property)) const
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|
BOOST_ASIO_NOEXCEPT_IF((
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call_traits<impl, T, void(Property)>::is_noexcept))
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{
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return BOOST_ASIO_MOVE_CAST(T)(t);
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}
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template <typename T, typename Property>
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BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
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call_traits<impl, T, void(Property)>::overload == call_require_member,
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typename call_traits<impl, T, void(Property)>::result_type
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>::type
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operator()(
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BOOST_ASIO_MOVE_ARG(T) t,
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BOOST_ASIO_MOVE_ARG(Property) p) const
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BOOST_ASIO_NOEXCEPT_IF((
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call_traits<impl, T, void(Property)>::is_noexcept))
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{
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return BOOST_ASIO_MOVE_CAST(T)(t).require(
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BOOST_ASIO_MOVE_CAST(Property)(p));
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}
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|
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template <typename T, typename Property>
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BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
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call_traits<impl, T, void(Property)>::overload == call_require_free,
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typename call_traits<impl, T, void(Property)>::result_type
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>::type
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operator()(
|
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BOOST_ASIO_MOVE_ARG(T) t,
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BOOST_ASIO_MOVE_ARG(Property) p) const
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BOOST_ASIO_NOEXCEPT_IF((
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call_traits<impl, T, void(Property)>::is_noexcept))
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|
{
|
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return require(
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BOOST_ASIO_MOVE_CAST(T)(t),
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BOOST_ASIO_MOVE_CAST(Property)(p));
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}
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|
template <typename T, typename Property>
|
|
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
|
|
call_traits<impl, T, void(Property)>::overload == call_prefer_member,
|
|
typename call_traits<impl, T, void(Property)>::result_type
|
|
>::type
|
|
operator()(
|
|
BOOST_ASIO_MOVE_ARG(T) t,
|
|
BOOST_ASIO_MOVE_ARG(Property) p) const
|
|
BOOST_ASIO_NOEXCEPT_IF((
|
|
call_traits<impl, T, void(Property)>::is_noexcept))
|
|
{
|
|
return BOOST_ASIO_MOVE_CAST(T)(t).prefer(
|
|
BOOST_ASIO_MOVE_CAST(Property)(p));
|
|
}
|
|
|
|
template <typename T, typename Property>
|
|
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
|
|
call_traits<impl, T, void(Property)>::overload == call_prefer_free,
|
|
typename call_traits<impl, T, void(Property)>::result_type
|
|
>::type
|
|
operator()(
|
|
BOOST_ASIO_MOVE_ARG(T) t,
|
|
BOOST_ASIO_MOVE_ARG(Property) p) const
|
|
BOOST_ASIO_NOEXCEPT_IF((
|
|
call_traits<impl, T, void(Property)>::is_noexcept))
|
|
{
|
|
return prefer(
|
|
BOOST_ASIO_MOVE_CAST(T)(t),
|
|
BOOST_ASIO_MOVE_CAST(Property)(p));
|
|
}
|
|
|
|
template <typename T, typename P0, typename P1>
|
|
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
|
|
call_traits<impl, T, void(P0, P1)>::overload == two_props,
|
|
typename call_traits<impl, T, void(P0, P1)>::result_type
|
|
>::type
|
|
operator()(
|
|
BOOST_ASIO_MOVE_ARG(T) t,
|
|
BOOST_ASIO_MOVE_ARG(P0) p0,
|
|
BOOST_ASIO_MOVE_ARG(P1) p1) const
|
|
BOOST_ASIO_NOEXCEPT_IF((
|
|
call_traits<impl, T, void(P0, P1)>::is_noexcept))
|
|
{
|
|
return (*this)(
|
|
(*this)(
|
|
BOOST_ASIO_MOVE_CAST(T)(t),
|
|
BOOST_ASIO_MOVE_CAST(P0)(p0)),
|
|
BOOST_ASIO_MOVE_CAST(P1)(p1));
|
|
}
|
|
|
|
template <typename T, typename P0, typename P1,
|
|
typename BOOST_ASIO_ELLIPSIS PN>
|
|
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
|
|
call_traits<impl, T,
|
|
void(P0, P1, PN BOOST_ASIO_ELLIPSIS)>::overload == n_props,
|
|
typename call_traits<impl, T,
|
|
void(P0, P1, PN BOOST_ASIO_ELLIPSIS)>::result_type
|
|
>::type
|
|
operator()(
|
|
BOOST_ASIO_MOVE_ARG(T) t,
|
|
BOOST_ASIO_MOVE_ARG(P0) p0,
|
|
BOOST_ASIO_MOVE_ARG(P1) p1,
|
|
BOOST_ASIO_MOVE_ARG(PN) BOOST_ASIO_ELLIPSIS pn) const
|
|
BOOST_ASIO_NOEXCEPT_IF((
|
|
call_traits<impl, T, void(P0, P1, PN BOOST_ASIO_ELLIPSIS)>::is_noexcept))
|
|
{
|
|
return (*this)(
|
|
(*this)(
|
|
BOOST_ASIO_MOVE_CAST(T)(t),
|
|
BOOST_ASIO_MOVE_CAST(P0)(p0)),
|
|
BOOST_ASIO_MOVE_CAST(P1)(p1),
|
|
BOOST_ASIO_MOVE_CAST(PN)(pn) BOOST_ASIO_ELLIPSIS);
|
|
}
|
|
};
|
|
|
|
template <typename T = impl>
|
|
struct static_instance
|
|
{
|
|
static const T instance;
|
|
};
|
|
|
|
template <typename T>
|
|
const T static_instance<T>::instance = {};
|
|
|
|
} // namespace boost_asio_prefer_fn
|
|
namespace boost {
|
|
namespace asio {
|
|
namespace {
|
|
|
|
static BOOST_ASIO_CONSTEXPR const boost_asio_prefer_fn::impl&
|
|
prefer = boost_asio_prefer_fn::static_instance<>::instance;
|
|
|
|
} // namespace
|
|
|
|
typedef boost_asio_prefer_fn::impl prefer_t;
|
|
|
|
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename... Properties>
|
|
struct can_prefer :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(Properties...)>::overload
|
|
!= boost_asio_prefer_fn::ill_formed>
|
|
{
|
|
};
|
|
|
|
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename P0 = void,
|
|
typename P1 = void, typename P2 = void>
|
|
struct can_prefer :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1, P2)>::overload
|
|
!= boost_asio_prefer_fn::ill_formed>
|
|
{
|
|
};
|
|
|
|
template <typename T, typename P0, typename P1>
|
|
struct can_prefer<T, P0, P1> :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1)>::overload
|
|
!= boost_asio_prefer_fn::ill_formed>
|
|
{
|
|
};
|
|
|
|
template <typename T, typename P0>
|
|
struct can_prefer<T, P0> :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0)>::overload
|
|
!= boost_asio_prefer_fn::ill_formed>
|
|
{
|
|
};
|
|
|
|
template <typename T>
|
|
struct can_prefer<T> :
|
|
false_type
|
|
{
|
|
};
|
|
|
|
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
|
|
|
|
template <typename T, typename BOOST_ASIO_ELLIPSIS Properties>
|
|
constexpr bool can_prefer_v
|
|
= can_prefer<T, Properties BOOST_ASIO_ELLIPSIS>::value;
|
|
|
|
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
|
|
|
|
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename... Properties>
|
|
struct is_nothrow_prefer :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(Properties...)>::is_noexcept>
|
|
{
|
|
};
|
|
|
|
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename P0 = void,
|
|
typename P1 = void, typename P2 = void>
|
|
struct is_nothrow_prefer :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1, P2)>::is_noexcept>
|
|
{
|
|
};
|
|
|
|
template <typename T, typename P0, typename P1>
|
|
struct is_nothrow_prefer<T, P0, P1> :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1)>::is_noexcept>
|
|
{
|
|
};
|
|
|
|
template <typename T, typename P0>
|
|
struct is_nothrow_prefer<T, P0> :
|
|
integral_constant<bool,
|
|
boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0)>::is_noexcept>
|
|
{
|
|
};
|
|
|
|
template <typename T>
|
|
struct is_nothrow_prefer<T> :
|
|
false_type
|
|
{
|
|
};
|
|
|
|
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
|
|
|
|
template <typename T, typename BOOST_ASIO_ELLIPSIS Properties>
|
|
constexpr bool is_nothrow_prefer_v
|
|
= is_nothrow_prefer<T, Properties BOOST_ASIO_ELLIPSIS>::value;
|
|
|
|
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
|
|
|
|
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename... Properties>
|
|
struct prefer_result
|
|
{
|
|
typedef typename boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(Properties...)>::result_type type;
|
|
};
|
|
|
|
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
template <typename T, typename P0 = void,
|
|
typename P1 = void, typename P2 = void>
|
|
struct prefer_result
|
|
{
|
|
typedef typename boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1, P2)>::result_type type;
|
|
};
|
|
|
|
template <typename T, typename P0, typename P1>
|
|
struct prefer_result<T, P0, P1>
|
|
{
|
|
typedef typename boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0, P1)>::result_type type;
|
|
};
|
|
|
|
template <typename T, typename P0>
|
|
struct prefer_result<T, P0>
|
|
{
|
|
typedef typename boost_asio_prefer_fn::call_traits<
|
|
prefer_t, T, void(P0)>::result_type type;
|
|
};
|
|
|
|
template <typename T>
|
|
struct prefer_result<T>
|
|
{
|
|
};
|
|
|
|
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
|
|
|
|
} // namespace asio
|
|
} // namespace boost
|
|
|
|
#endif // defined(GENERATING_DOCUMENTATION)
|
|
|
|
#include <boost/asio/detail/pop_options.hpp>
|
|
|
|
#endif // BOOST_ASIO_PREFER_HPP
|