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diff --git a/boost/asio/associated_allocator.hpp b/boost/asio/associated_allocator.hpp
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+//
+// associated_allocator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 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_ASSOCIATED_ALLOCATOR_HPP
+#define BOOST_ASIO_ASSOCIATED_ALLOCATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+#include <memory>
+#include <boost/asio/detail/type_traits.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+namespace detail {
+
+template <typename>
+struct associated_allocator_check
+{
+  typedef void type;
+};
+
+template <typename T, typename E, typename = void>
+struct associated_allocator_impl
+{
+  typedef E type;
+
+  static type get(const T&, const E& e) BOOST_ASIO_NOEXCEPT
+  {
+    return e;
+  }
+};
+
+template <typename T, typename E>
+struct associated_allocator_impl<T, E,
+  typename associated_allocator_check<typename T::allocator_type>::type>
+{
+  typedef typename T::allocator_type type;
+
+  static type get(const T& t, const E&) BOOST_ASIO_NOEXCEPT
+  {
+    return t.get_allocator();
+  }
+};
+
+} // namespace detail
+
+/// Traits type used to obtain the allocator associated with an object.
+/**
+ * A program may specialise this traits type if the @c T template parameter in
+ * the specialisation is a user-defined type. The template parameter @c
+ * Allocator shall be a type meeting the Allocator requirements.
+ *
+ * Specialisations shall meet the following requirements, where @c t is a const
+ * reference to an object of type @c T, and @c a is an object of type @c
+ * Allocator.
+ *
+ * @li Provide a nested typedef @c type that identifies a type meeting the
+ * Allocator requirements.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t) and with return type @c type.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t,a) and with return type @c type.
+ */
+template <typename T, typename Allocator = std::allocator<void> >
+struct associated_allocator
+{
+  /// If @c T has a nested type @c allocator_type, <tt>T::allocator_type</tt>.
+  /// Otherwise @c Allocator.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef see_below type;
+#else // defined(GENERATING_DOCUMENTATION)
+  typedef typename detail::associated_allocator_impl<T, Allocator>::type type;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// If @c T has a nested type @c allocator_type, returns
+  /// <tt>t.get_allocator()</tt>. Otherwise returns @c a.
+  static type get(const T& t,
+      const Allocator& a = Allocator()) BOOST_ASIO_NOEXCEPT
+  {
+    return detail::associated_allocator_impl<T, Allocator>::get(t, a);
+  }
+};
+
+/// Helper function to obtain an object's associated allocator.
+/**
+ * @returns <tt>associated_allocator<T>::get(t)</tt>
+ */
+template <typename T>
+inline typename associated_allocator<T>::type
+get_associated_allocator(const T& t) BOOST_ASIO_NOEXCEPT
+{
+  return associated_allocator<T>::get(t);
+}
+
+/// Helper function to obtain an object's associated allocator.
+/**
+ * @returns <tt>associated_allocator<T, Allocator>::get(t, a)</tt>
+ */
+template <typename T, typename Allocator>
+inline typename associated_allocator<T, Allocator>::type
+get_associated_allocator(const T& t, const Allocator& a) BOOST_ASIO_NOEXCEPT
+{
+  return associated_allocator<T, Allocator>::get(t, a);
+}
+
+#if defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES)
+
+template <typename T, typename Allocator = std::allocator<void> >
+using associated_allocator_t
+  = typename associated_allocator<T, Allocator>::type;
+
+#endif // defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES)
+
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_ASSOCIATED_ALLOCATOR_HPP