Initial Commit

include/asio/traits/equality_comparable.hpp

@@ -0,0 +1,100 @@
+//
+// traits/equality_comparable.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_EQUALITY_COMPARABLE_HPP
+#define ASIO_TRAITS_EQUALITY_COMPARABLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename = void>
+struct equality_comparable_default;
+
+template <typename T, typename = void>
+struct equality_comparable;
+
+} // namespace traits
+namespace detail {
+
+struct no_equality_comparable
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT)
+
+template <typename T, typename = void>
+struct equality_comparable_trait : no_equality_comparable
+{
+};
+
+template <typename T>
+struct equality_comparable_trait<T,
+  void_t<
+    decltype(
+      static_cast<void>(
+        static_cast<bool>(declval<const T>() == declval<const T>())
+      ),
+      static_cast<void>(
+        static_cast<bool>(declval<const T>() != declval<const T>())
+      )
+    )
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<const T>() == declval<const T>())
+      && noexcept(declval<const T>() != declval<const T>());
+};
+
+#else // defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT)
+
+template <typename T, typename = void>
+struct equality_comparable_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value,
+    no_equality_comparable,
+    traits::equality_comparable<decay_t<T>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename>
+struct equality_comparable_default : detail::equality_comparable_trait<T>
+{
+};
+
+template <typename T, typename>
+struct equality_comparable : equality_comparable_default<T>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#endif // ASIO_TRAITS_EQUALITY_COMPARABLE_HPP

include/asio/traits/execute_member.hpp

@@ -0,0 +1,104 @@
+//
+// traits/execute_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_EXECUTE_MEMBER_HPP
+#define ASIO_TRAITS_EXECUTE_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename F, typename = void>
+struct execute_member_default;
+
+template <typename T, typename F, typename = void>
+struct execute_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_execute_member
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
+
+template <typename T, typename F, typename = void>
+struct execute_member_trait : no_execute_member
+{
+};
+
+template <typename T, typename F>
+struct execute_member_trait<T, F,
+  void_t<
+    decltype(declval<T>().execute(declval<F>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    declval<T>().execute(declval<F>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<T>().execute(declval<F>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
+
+template <typename T, typename F, typename = void>
+struct execute_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<F, decay_t<F>>::value,
+    no_execute_member,
+    traits::execute_member<
+      decay_t<T>,
+      decay_t<F>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename F, typename>
+struct execute_member_default :
+  detail::execute_member_trait<T, F>
+{
+};
+
+template <typename T, typename F, typename>
+struct execute_member :
+  execute_member_default<T, F>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_EXECUTE_MEMBER_HPP

include/asio/traits/prefer_free.hpp

@@ -0,0 +1,104 @@
+//
+// traits/prefer_free.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_PREFER_FREE_HPP
+#define ASIO_TRAITS_PREFER_FREE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_PREFER_FREE_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct prefer_free_default;
+
+template <typename T, typename Property, typename = void>
+struct prefer_free;
+
+} // namespace traits
+namespace detail {
+
+struct no_prefer_free
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_PREFER_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct prefer_free_trait : no_prefer_free
+{
+};
+
+template <typename T, typename Property>
+struct prefer_free_trait<T, Property,
+  void_t<
+    decltype(prefer(declval<T>(), declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    prefer(declval<T>(), declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(prefer(declval<T>(), declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_PREFER_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct prefer_free_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_prefer_free,
+    traits::prefer_free<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_PREFER_FREE_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct prefer_free_default :
+  detail::prefer_free_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct prefer_free :
+  prefer_free_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_PREFER_FREE_HPP

include/asio/traits/prefer_member.hpp

@@ -0,0 +1,104 @@
+//
+// traits/prefer_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_PREFER_MEMBER_HPP
+#define ASIO_TRAITS_PREFER_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct prefer_member_default;
+
+template <typename T, typename Property, typename = void>
+struct prefer_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_prefer_member
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct prefer_member_trait : no_prefer_member
+{
+};
+
+template <typename T, typename Property>
+struct prefer_member_trait<T, Property,
+  void_t<
+    decltype(declval<T>().prefer(declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    declval<T>().prefer(declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<T>().prefer(declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct prefer_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_prefer_member,
+    traits::prefer_member<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct prefer_member_default :
+  detail::prefer_member_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct prefer_member :
+  prefer_member_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_PREFER_MEMBER_HPP

include/asio/traits/query_free.hpp

@@ -0,0 +1,104 @@
+//
+// traits/query_free.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_QUERY_FREE_HPP
+#define ASIO_TRAITS_QUERY_FREE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct query_free_default;
+
+template <typename T, typename Property, typename = void>
+struct query_free;
+
+} // namespace traits
+namespace detail {
+
+struct no_query_free
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct query_free_trait : no_query_free
+{
+};
+
+template <typename T, typename Property>
+struct query_free_trait<T, Property,
+  void_t<
+    decltype(query(declval<T>(), declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    query(declval<T>(), declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(query(declval<T>(), declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct query_free_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_query_free,
+    traits::query_free<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct query_free_default :
+  detail::query_free_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct query_free :
+  query_free_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_QUERY_FREE_HPP

include/asio/traits/query_member.hpp

@@ -0,0 +1,104 @@
+//
+// traits/query_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_QUERY_MEMBER_HPP
+#define ASIO_TRAITS_QUERY_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct query_member_default;
+
+template <typename T, typename Property, typename = void>
+struct query_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_query_member
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct query_member_trait : no_query_member
+{
+};
+
+template <typename T, typename Property>
+struct query_member_trait<T, Property,
+  void_t<
+    decltype(declval<T>().query(declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    declval<T>().query(declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<T>().query(declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct query_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_query_member,
+    traits::query_member<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct query_member_default :
+  detail::query_member_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct query_member :
+  query_member_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_QUERY_MEMBER_HPP

include/asio/traits/query_static_constexpr_member.hpp

@@ -0,0 +1,101 @@
+//
+// traits/query_static_constexpr_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_QUERY_STATIC_CONSTEXPR_MEMBER_HPP
+#define ASIO_TRAITS_QUERY_STATIC_CONSTEXPR_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_CONSTANT_EXPRESSION_SFINAE) \
+  && defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_CONSTANT_EXPRESSION_SFINAE)
+       //   && defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct query_static_constexpr_member_default;
+
+template <typename T, typename Property, typename = void>
+struct query_static_constexpr_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_query_static_constexpr_member
+{
+  static constexpr bool is_valid = false;
+};
+
+template <typename T, typename Property, typename = void>
+struct query_static_constexpr_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_query_static_constexpr_member,
+    traits::query_static_constexpr_member<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#if defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
+
+template <typename T, typename Property>
+struct query_static_constexpr_member_trait<T, Property,
+  enable_if_t<
+    (static_cast<void>(T::query(Property{})), true)
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(T::query(Property{}));
+
+  static constexpr bool is_noexcept = noexcept(T::query(Property{}));
+
+  static constexpr result_type value() noexcept(is_noexcept)
+  {
+    return T::query(Property{});
+  }
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct query_static_constexpr_member_default :
+  detail::query_static_constexpr_member_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct query_static_constexpr_member :
+  query_static_constexpr_member_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_QUERY_STATIC_CONSTEXPR_MEMBER_HPP

include/asio/traits/require_concept_free.hpp

@@ -0,0 +1,104 @@
+//
+// traits/require_concept_free.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_REQUIRE_CONCEPT_FREE_HPP
+#define ASIO_TRAITS_REQUIRE_CONCEPT_FREE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_FREE_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct require_concept_free_default;
+
+template <typename T, typename Property, typename = void>
+struct require_concept_free;
+
+} // namespace traits
+namespace detail {
+
+struct no_require_concept_free
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_concept_free_trait : no_require_concept_free
+{
+};
+
+template <typename T, typename Property>
+struct require_concept_free_trait<T, Property,
+  void_t<
+    decltype(require_concept(declval<T>(), declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    require_concept(declval<T>(), declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(require_concept(declval<T>(), declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_concept_free_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_require_concept_free,
+    traits::require_concept_free<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_FREE_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct require_concept_free_default :
+  detail::require_concept_free_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct require_concept_free :
+  require_concept_free_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_REQUIRE_CONCEPT_FREE_HPP

include/asio/traits/require_concept_member.hpp

@@ -0,0 +1,104 @@
+//
+// traits/require_concept_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_REQUIRE_CONCEPT_MEMBER_HPP
+#define ASIO_TRAITS_REQUIRE_CONCEPT_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct require_concept_member_default;
+
+template <typename T, typename Property, typename = void>
+struct require_concept_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_require_concept_member
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_concept_member_trait : no_require_concept_member
+{
+};
+
+template <typename T, typename Property>
+struct require_concept_member_trait<T, Property,
+  void_t<
+    decltype(declval<T>().require_concept(declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    declval<T>().require_concept(declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<T>().require_concept(declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_concept_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_require_concept_member,
+    traits::require_concept_member<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_REQUIRE_CONCEPT_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct require_concept_member_default :
+  detail::require_concept_member_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct require_concept_member :
+  require_concept_member_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_REQUIRE_CONCEPT_MEMBER_HPP

include/asio/traits/require_free.hpp

@@ -0,0 +1,104 @@
+//
+// traits/require_free.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_REQUIRE_FREE_HPP
+#define ASIO_TRAITS_REQUIRE_FREE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+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
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(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,
+  void_t<
+    decltype(require(declval<T>(), declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    require(declval<T>(), declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(require(declval<T>(), declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_free_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_require_free,
+    traits::require_free<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(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
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_REQUIRE_FREE_HPP

include/asio/traits/require_member.hpp

@@ -0,0 +1,104 @@
+//
+// traits/require_member.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_REQUIRE_MEMBER_HPP
+#define ASIO_TRAITS_REQUIRE_MEMBER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT 1
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct require_member_default;
+
+template <typename T, typename Property, typename = void>
+struct require_member;
+
+} // namespace traits
+namespace detail {
+
+struct no_require_member
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+#if defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_member_trait : no_require_member
+{
+};
+
+template <typename T, typename Property>
+struct require_member_trait<T, Property,
+  void_t<
+    decltype(declval<T>().require(declval<Property>()))
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+    declval<T>().require(declval<Property>()));
+
+  static constexpr bool is_noexcept =
+    noexcept(declval<T>().require(declval<Property>()));
+};
+
+#else // defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT)
+
+template <typename T, typename Property, typename = void>
+struct require_member_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_require_member,
+    traits::require_member<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct require_member_default :
+  detail::require_member_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct require_member :
+  require_member_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_REQUIRE_MEMBER_HPP

include/asio/traits/static_query.hpp

@@ -0,0 +1,102 @@
+//
+// traits/static_query.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_STATIC_QUERY_HPP
+#define ASIO_TRAITS_STATIC_QUERY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_HAS_VARIABLE_TEMPLATES) \
+  && defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+# define ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT 1
+#endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)
+       //   && defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct static_query_default;
+
+template <typename T, typename Property, typename = void>
+struct static_query;
+
+} // namespace traits
+namespace detail {
+
+struct no_static_query
+{
+  static constexpr bool is_valid = false;
+  static constexpr bool is_noexcept = false;
+};
+
+template <typename T, typename Property, typename = void>
+struct static_query_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_static_query,
+    traits::static_query<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
+
+template <typename T, typename Property>
+struct static_query_trait<T, Property,
+  void_t<
+    decltype(decay_t<Property>::template static_query_v<T>)
+  >>
+{
+  static constexpr bool is_valid = true;
+
+  using result_type = decltype(
+      decay_t<Property>::template static_query_v<T>);
+
+  static constexpr bool is_noexcept =
+    noexcept(decay_t<Property>::template static_query_v<T>);
+
+  static constexpr result_type value() noexcept(is_noexcept)
+  {
+    return decay_t<Property>::template static_query_v<T>;
+  }
+};
+
+#endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct static_query_default : detail::static_query_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct static_query : static_query_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_STATIC_QUERY_HPP

include/asio/traits/static_require.hpp

@@ -0,0 +1,115 @@
+//
+// traits/static_require.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_STATIC_REQUIRE_HPP
+#define ASIO_TRAITS_STATIC_REQUIRE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/traits/static_query.hpp"
+
+#define ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT 1
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct static_require_default;
+
+template <typename T, typename Property, typename = void>
+struct static_require;
+
+} // namespace traits
+namespace detail {
+
+struct no_static_require
+{
+  static constexpr bool is_valid = false;
+};
+
+template <typename T, typename Property, typename = void>
+struct static_require_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_static_require,
+    traits::static_require<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+template <typename T, typename Property>
+struct static_require_trait<T, Property,
+  enable_if_t<
+    decay_t<Property>::value() == traits::static_query<T, Property>::value()
+  >>
+{
+  static constexpr bool is_valid = true;
+};
+
+#else // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+false_type static_require_test(...);
+
+template <typename T, typename Property>
+true_type static_require_test(T*, Property*,
+    enable_if_t<
+      Property::value() == traits::static_query<T, Property>::value()
+    >* = 0);
+
+template <typename T, typename Property>
+struct has_static_require
+{
+  static constexpr bool value =
+    decltype((static_require_test)(
+      static_cast<T*>(0), static_cast<Property*>(0)))::value;
+};
+
+template <typename T, typename Property>
+struct static_require_trait<T, Property,
+  enable_if_t<
+    has_static_require<decay_t<T>,
+      decay_t<Property>>::value
+  >>
+{
+  static constexpr bool is_valid = true;
+};
+
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct static_require_default : detail::static_require_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct static_require : static_require_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_STATIC_REQUIRE_HPP

include/asio/traits/static_require_concept.hpp

@@ -0,0 +1,116 @@
+//
+// traits/static_require_concept.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 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 ASIO_TRAITS_STATIC_REQUIRE_CONCEPT_HPP
+#define ASIO_TRAITS_STATIC_REQUIRE_CONCEPT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/traits/static_query.hpp"
+
+#define ASIO_HAS_DEDUCED_STATIC_REQUIRE_CONCEPT_TRAIT 1
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace traits {
+
+template <typename T, typename Property, typename = void>
+struct static_require_concept_default;
+
+template <typename T, typename Property, typename = void>
+struct static_require_concept;
+
+} // namespace traits
+namespace detail {
+
+struct no_static_require_concept
+{
+  static constexpr bool is_valid = false;
+};
+
+template <typename T, typename Property, typename = void>
+struct static_require_concept_trait :
+  conditional_t<
+    is_same<T, decay_t<T>>::value
+      && is_same<Property, decay_t<Property>>::value,
+    no_static_require_concept,
+    traits::static_require_concept<
+      decay_t<T>,
+      decay_t<Property>>
+  >
+{
+};
+
+#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+template <typename T, typename Property>
+struct static_require_concept_trait<T, Property,
+  enable_if_t<
+    decay_t<Property>::value() == traits::static_query<T, Property>::value()
+  >>
+{
+  static constexpr bool is_valid = true;
+};
+
+#else // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+false_type static_require_concept_test(...);
+
+template <typename T, typename Property>
+true_type static_require_concept_test(T*, Property*,
+    enable_if_t<
+      Property::value() == traits::static_query<T, Property>::value()
+    >* = 0);
+
+template <typename T, typename Property>
+struct has_static_require_concept
+{
+  static constexpr bool value =
+    decltype((static_require_concept_test)(
+      static_cast<T*>(0), static_cast<Property*>(0)))::value;
+};
+
+template <typename T, typename Property>
+struct static_require_concept_trait<T, Property,
+  enable_if_t<
+    has_static_require_concept<decay_t<T>,
+      decay_t<Property>>::value
+  >>
+{
+  static constexpr bool is_valid = true;
+};
+
+#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
+
+} // namespace detail
+namespace traits {
+
+template <typename T, typename Property, typename>
+struct static_require_concept_default :
+  detail::static_require_concept_trait<T, Property>
+{
+};
+
+template <typename T, typename Property, typename>
+struct static_require_concept : static_require_concept_default<T, Property>
+{
+};
+
+} // namespace traits
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_TRAITS_STATIC_REQUIRE_CONCEPT_HPP