Initial Commit

include/asio/traits/static_require.hpp

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+//
+// 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