Gecko [ 0.0.0.0 ]

Name	Size	Permission
algorithmfwd.h	24.05 KB	-rw-r--r--
align.h	3.62 KB	-rw-r--r--
alloc_traits.h	31.4 KB	-rw-r--r--
allocated_ptr.h	3.25 KB	-rw-r--r--
allocator.h	8.61 KB	-rw-r--r--
atomic_base.h	60.9 KB	-rw-r--r--
atomic_futex.h	12.19 KB	-rw-r--r--
atomic_lockfree_defines.h	2.3 KB	-rw-r--r--
atomic_timed_wait.h	13.18 KB	-rw-r--r--
atomic_wait.h	12.33 KB	-rw-r--r--
basic_ios.h	15.85 KB	-rw-r--r--
basic_ios.tcc	5.67 KB	-rw-r--r--
basic_string.h	161.58 KB	-rw-r--r--
basic_string.tcc	30.7 KB	-rw-r--r--
boost_concept_check.h	29.13 KB	-rw-r--r--
c++0x_warning.h	1.44 KB	-rw-r--r--
char_traits.h	28.54 KB	-rw-r--r--
charconv.h	3.58 KB	-rw-r--r--
chrono.h	47.09 KB	-rw-r--r--
chrono_io.h	126.98 KB	-rw-r--r--
codecvt.h	24.9 KB	-rw-r--r--
concept_check.h	3.32 KB	-rw-r--r--
cow_string.h	134.11 KB	-rw-r--r--
cpp_type_traits.h	14.54 KB	-rw-r--r--
cxxabi_forced.h	1.77 KB	-rw-r--r--
cxxabi_init_exception.h	2.17 KB	-rw-r--r--
deque.tcc	41.43 KB	-rw-r--r--
elements_of.h	2.13 KB	-rw-r--r--
enable_special_members.h	12.16 KB	-rw-r--r--
erase_if.h	2.08 KB	-rw-r--r--
exception.h	2.41 KB	-rw-r--r--
exception_defines.h	1.61 KB	-rw-r--r--
exception_ptr.h	8.02 KB	-rw-r--r--
forward_list.h	50 KB	-rw-r--r--
forward_list.tcc	13.71 KB	-rw-r--r--
fs_dir.h	17.94 KB	-rw-r--r--
fs_fwd.h	10.91 KB	-rw-r--r--
fs_ops.h	10.49 KB	-rw-r--r--
fs_path.h	41.47 KB	-rw-r--r--
fstream.tcc	32.64 KB	-rw-r--r--
functexcept.h	4.17 KB	-rw-r--r--
functional_hash.h	8.79 KB	-rw-r--r--
gslice.h	5.52 KB	-rw-r--r--
gslice_array.h	7.71 KB	-rw-r--r--
hash_bytes.h	2.1 KB	-rw-r--r--
hashtable.h	88.15 KB	-rw-r--r--
hashtable_policy.h	64.73 KB	-rw-r--r--
indirect_array.h	7.72 KB	-rw-r--r--
invoke.h	6.08 KB	-rw-r--r--
ios_base.h	32.29 KB	-rw-r--r--
istream.tcc	32.16 KB	-rw-r--r--
iterator_concepts.h	34.38 KB	-rw-r--r--
list.tcc	17.63 KB	-rw-r--r--
locale_classes.h	25.15 KB	-rw-r--r--
locale_classes.tcc	10.76 KB	-rw-r--r--
locale_conv.h	18.74 KB	-rw-r--r--
locale_facets.h	92.12 KB	-rw-r--r--
locale_facets.tcc	40.61 KB	-rw-r--r--
locale_facets_nonio.h	69.1 KB	-rw-r--r--
locale_facets_nonio.tcc	55.86 KB	-rw-r--r--
localefwd.h	5.8 KB	-rw-r--r--
mask_array.h	7.77 KB	-rw-r--r--
max_size_type.h	22 KB	-rw-r--r--
memory_resource.h	15.8 KB	-rw-r--r--
memoryfwd.h	2.5 KB	-rw-r--r--
mofunc_impl.h	7.45 KB	-rw-r--r--
move.h	7.62 KB	-rw-r--r--
move_only_function.h	6.15 KB	-rw-r--r--
nested_exception.h	7.51 KB	-rw-r--r--
new_allocator.h	7.31 KB	-rw-r--r--
node_handle.h	11.1 KB	-rw-r--r--
ostream.tcc	12.02 KB	-rw-r--r--
ostream_insert.h	3.98 KB	-rw-r--r--
out_ptr.h	14.14 KB	-rw-r--r--
parse_numbers.h	7.8 KB	-rw-r--r--
postypes.h	7.33 KB	-rw-r--r--
predefined_ops.h	9.94 KB	-rw-r--r--
ptr_traits.h	8.05 KB	-rw-r--r--
quoted_string.h	5.01 KB	-rw-r--r--
random.h	181.57 KB	-rw-r--r--
random.tcc	103.49 KB	-rw-r--r--
range_access.h	11.66 KB	-rw-r--r--
ranges_algo.h	129.22 KB	-rw-r--r--
ranges_algobase.h	18.63 KB	-rw-r--r--
ranges_base.h	28.99 KB	-rw-r--r--
ranges_cmp.h	5.74 KB	-rw-r--r--
ranges_uninitialized.h	17.71 KB	-rw-r--r--
ranges_util.h	25.84 KB	-rw-r--r--
refwrap.h	15.05 KB	-rw-r--r--
regex.h	104.49 KB	-rw-r--r--
regex.tcc	16.1 KB	-rw-r--r--
regex_automaton.h	10.55 KB	-rw-r--r--
regex_automaton.tcc	7.6 KB	-rw-r--r--
regex_compiler.h	15.92 KB	-rw-r--r--
regex_compiler.tcc	18.48 KB	-rw-r--r--
regex_constants.h	14.77 KB	-rw-r--r--
regex_error.h	5.35 KB	-rw-r--r--
regex_executor.h	8.81 KB	-rw-r--r--
regex_executor.tcc	18.49 KB	-rw-r--r--
regex_scanner.h	6.88 KB	-rw-r--r--
regex_scanner.tcc	14.59 KB	-rw-r--r--
requires_hosted.h	1.36 KB	-rw-r--r--
sat_arith.h	4.64 KB	-rw-r--r--
semaphore_base.h	7.7 KB	-rw-r--r--
shared_ptr.h	38.26 KB	-rw-r--r--
shared_ptr_atomic.h	24.12 KB	-rw-r--r--
shared_ptr_base.h	65.58 KB	-rw-r--r--
slice_array.h	9.39 KB	-rw-r--r--
specfun.h	46.09 KB	-rw-r--r--
sstream.tcc	9.91 KB	-rw-r--r--
std_abs.h	4.63 KB	-rw-r--r--
std_function.h	23.35 KB	-rw-r--r--
std_mutex.h	6.73 KB	-rw-r--r--
std_thread.h	10.02 KB	-rw-r--r--
stl_algo.h	210.46 KB	-rw-r--r--
stl_algobase.h	79.62 KB	-rw-r--r--
stl_bvector.h	41.68 KB	-rw-r--r--
stl_construct.h	8.61 KB	-rw-r--r--
stl_deque.h	76.46 KB	-rw-r--r--
stl_function.h	44.2 KB	-rw-r--r--
stl_heap.h	20.38 KB	-rw-r--r--
stl_iterator.h	93.68 KB	-rw-r--r--
stl_iterator_base_funcs.h	8.75 KB	-rw-r--r--
stl_iterator_base_types.h	9.48 KB	-rw-r--r--
stl_list.h	70.78 KB	-rw-r--r--
stl_map.h	54.84 KB	-rw-r--r--
stl_multimap.h	42.71 KB	-rw-r--r--
stl_multiset.h	36.87 KB	-rw-r--r--
stl_numeric.h	14.25 KB	-rw-r--r--
stl_pair.h	43.42 KB	-rw-r--r--
stl_queue.h	28.04 KB	-rw-r--r--
stl_raw_storage_iter.h	3.91 KB	-rw-r--r--
stl_relops.h	4.47 KB	-rw-r--r--
stl_set.h	37.13 KB	-rw-r--r--
stl_stack.h	13.7 KB	-rw-r--r--
stl_tempbuf.h	10.17 KB	-rw-r--r--
stl_tree.h	72.02 KB	-rw-r--r--
stl_uninitialized.h	35.65 KB	-rw-r--r--
stl_vector.h	69.15 KB	-rw-r--r--
stream_iterator.h	8.2 KB	-rw-r--r--
streambuf.tcc	4.58 KB	-rw-r--r--
streambuf_iterator.h	15.57 KB	-rw-r--r--
string_view.tcc	7 KB	-rw-r--r--
stringfwd.h	2.56 KB	-rw-r--r--
text_encoding-data.h	24.3 KB	-rw-r--r--
this_thread_sleep.h	3.21 KB	-rw-r--r--
unicode-data.h	25.4 KB	-rw-r--r--
unicode.h	29.66 KB	-rw-r--r--
uniform_int_dist.h	13 KB	-rw-r--r--
unique_lock.h	6.32 KB	-rw-r--r--
unique_ptr.h	35.96 KB	-rw-r--r--
unordered_map.h	75.45 KB	-rw-r--r--
unordered_set.h	61.91 KB	-rw-r--r--
uses_allocator.h	6.91 KB	-rw-r--r--
uses_allocator_args.h	8.52 KB	-rw-r--r--
utility.h	8.55 KB	-rw-r--r--
valarray_after.h	22.74 KB	-rw-r--r--
valarray_array.h	20.8 KB	-rw-r--r--
valarray_array.tcc	7.08 KB	-rw-r--r--
valarray_before.h	18.69 KB	-rw-r--r--
vector.tcc	37.12 KB	-rw-r--r--
version.h	79.04 KB	-rw-r--r--

Code Editor : alloc_traits.h

// Allocator traits -*- C++ -*-

// Copyright (C) 2011-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/alloc_traits.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{memory}
 */

#ifndef _ALLOC_TRAITS_H
#define _ALLOC_TRAITS_H 1

#include <bits/stl_construct.h>
#include <bits/memoryfwd.h>
#if __cplusplus >= 201103L
# include <bits/ptr_traits.h>
# include <ext/numeric_traits.h>
# if _GLIBCXX_HOSTED
#  include <bits/allocator.h>
# endif
# if __cpp_exceptions
#  include <bits/stl_iterator.h> // __make_move_if_noexcept_iterator
# endif
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#if __cplusplus >= 201103L

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wc++14-extensions" // for variable templates
#pragma GCC diagnostic ignored "-Wc++17-extensions" // for if-constexpr

/// @cond undocumented
  struct __allocator_traits_base
  {
    template<typename _Tp, typename _Up, typename = void>
      struct __rebind : __replace_first_arg<_Tp, _Up>
      {
	static_assert(is_same<
	  typename __replace_first_arg<_Tp, typename _Tp::value_type>::type,
			_Tp>::value,
	  "allocator_traits<A>::rebind_alloc<A::value_type> must be A");
      };

template<typename _Tp, typename _Up>
      struct __rebind<_Tp, _Up,
		      __void_t<typename _Tp::template rebind<_Up>::other>>
      {
	using type = typename _Tp::template rebind<_Up>::other;

static_assert(is_same<
	  typename _Tp::template rebind<typename _Tp::value_type>::other,
			_Tp>::value,
	  "allocator_traits<A>::rebind_alloc<A::value_type> must be A");
      };

protected:
    template<typename _Tp>
      using __pointer = typename _Tp::pointer;
    template<typename _Tp>
      using __c_pointer = typename _Tp::const_pointer;
    template<typename _Tp>
      using __v_pointer = typename _Tp::void_pointer;
    template<typename _Tp>
      using __cv_pointer = typename _Tp::const_void_pointer;
    template<typename _Tp>
      using __pocca = typename _Tp::propagate_on_container_copy_assignment;
    template<typename _Tp>
      using __pocma = typename _Tp::propagate_on_container_move_assignment;
    template<typename _Tp>
      using __pocs = typename _Tp::propagate_on_container_swap;
    template<typename _Tp>
      using __equal = __type_identity<typename _Tp::is_always_equal>;

// __has_construct is true if a.construct(p, args...) is well-formed.
    // __can_construct is true if either __has_construct is true, or if
    // a placement new-expression for T(args...) is well-formed. We use this
    // to constrain allocator_traits::construct, as a libstdc++ extension.
    template<typename _Alloc, typename _Tp, typename... _Args>
      using __construct_t
	= decltype(std::declval<_Alloc&>().construct(std::declval<_Tp*>(),
						     std::declval<_Args>()...));
    template<typename _Alloc, typename _Tp, typename, typename... _Args>
      static constexpr bool __has_construct_impl = false;
    template<typename _Alloc, typename _Tp, typename... _Args>
      static constexpr bool
      __has_construct_impl<_Alloc, _Tp,
			   __void_t<__construct_t<_Alloc, _Tp, _Args...>>,
			   _Args...>
	= true;
    template<typename _Alloc, typename _Tp, typename... _Args>
      static constexpr bool __has_construct
	= __has_construct_impl<_Alloc, _Tp, void, _Args...>;
    template<typename _Tp, typename... _Args>
      using __new_expr_t
	= decltype(::new((void*)0) _Tp(std::declval<_Args>()...));
    template<typename _Tp, typename, typename... _Args>
      static constexpr bool __has_new_expr = false;
    template<typename _Tp, typename... _Args>
      static constexpr bool
      __has_new_expr<_Tp, __void_t<__new_expr_t<_Tp, _Args...>>, _Args...>
	= true;
    template<typename _Alloc, typename _Tp, typename... _Args>
      static constexpr bool __can_construct
	= __has_construct<_Alloc, _Tp, _Args...>
	    || __has_new_expr<_Tp, void, _Args...>;
  };

template<typename _Alloc, typename _Up>
    using __alloc_rebind
      = typename __allocator_traits_base::template __rebind<_Alloc, _Up>::type;
  /// @endcond

/**
   * @brief  Uniform interface to all allocator types.
   * @headerfile memory
   * @ingroup allocators
   * @since C++11
  */
  template<typename _Alloc>
    struct allocator_traits : __allocator_traits_base
    {
      /// The allocator type
      typedef _Alloc allocator_type;
      /// The allocated type
      typedef typename _Alloc::value_type value_type;

/**
       * @brief   The allocator's pointer type.
       *
       * @c Alloc::pointer if that type exists, otherwise @c value_type*
      */
      using pointer = __detected_or_t<value_type*, __pointer, _Alloc>;

private:
      // Select _Func<_Alloc> or pointer_traits<pointer>::rebind<_Tp>
      template<template<typename> class _Func, typename _Tp, typename = void>
	struct _Ptr
	{
	  using type = typename pointer_traits<pointer>::template rebind<_Tp>;
	};

template<template<typename> class _Func, typename _Tp>
	struct _Ptr<_Func, _Tp, __void_t<_Func<_Alloc>>>
	{
	  using type = _Func<_Alloc>;
	};

// Select _A2::difference_type or pointer_traits<_Ptr>::difference_type
      template<typename _A2, typename _PtrT, typename = void>
	struct _Diff
	{ using type = typename pointer_traits<_PtrT>::difference_type; };

template<typename _A2, typename _PtrT>
	struct _Diff<_A2, _PtrT, __void_t<typename _A2::difference_type>>
	{ using type = typename _A2::difference_type; };

// Select _A2::size_type or make_unsigned<_DiffT>::type
      template<typename _A2, typename _DiffT, typename = void>
	struct _Size : make_unsigned<_DiffT> { };

template<typename _A2, typename _DiffT>
	struct _Size<_A2, _DiffT, __void_t<typename _A2::size_type>>
	{ using type = typename _A2::size_type; };

public:
      /**
       * @brief   The allocator's const pointer type.
       *
       * @c Alloc::const_pointer if that type exists, otherwise
       * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
      */
      using const_pointer = typename _Ptr<__c_pointer, const value_type>::type;

/**
       * @brief   The allocator's void pointer type.
       *
       * @c Alloc::void_pointer if that type exists, otherwise
       * <tt> pointer_traits<pointer>::rebind<void> </tt>
      */
      using void_pointer = typename _Ptr<__v_pointer, void>::type;

/**
       * @brief   The allocator's const void pointer type.
       *
       * @c Alloc::const_void_pointer if that type exists, otherwise
       * <tt> pointer_traits<pointer>::rebind<const void> </tt>
      */
      using const_void_pointer = typename _Ptr<__cv_pointer, const void>::type;

/**
       * @brief   The allocator's difference type
       *
       * @c Alloc::difference_type if that type exists, otherwise
       * <tt> pointer_traits<pointer>::difference_type </tt>
      */
      using difference_type = typename _Diff<_Alloc, pointer>::type;

/**
       * @brief   The allocator's size type
       *
       * @c Alloc::size_type if that type exists, otherwise
       * <tt> make_unsigned<difference_type>::type </tt>
      */
      using size_type = typename _Size<_Alloc, difference_type>::type;

/**
       * @brief   How the allocator is propagated on copy assignment
       *
       * @c Alloc::propagate_on_container_copy_assignment if that type exists,
       * otherwise @c false_type
      */
      using propagate_on_container_copy_assignment
	= __detected_or_t<false_type, __pocca, _Alloc>;

/**
       * @brief   How the allocator is propagated on move assignment
       *
       * @c Alloc::propagate_on_container_move_assignment if that type exists,
       * otherwise @c false_type
      */
      using propagate_on_container_move_assignment
	= __detected_or_t<false_type, __pocma, _Alloc>;

/**
       * @brief   How the allocator is propagated on swap
       *
       * @c Alloc::propagate_on_container_swap if that type exists,
       * otherwise @c false_type
      */
      using propagate_on_container_swap
	= __detected_or_t<false_type, __pocs, _Alloc>;

/**
       * @brief   Whether all instances of the allocator type compare equal.
       *
       * @c Alloc::is_always_equal if that type exists,
       * otherwise @c is_empty<Alloc>::type
      */
      using is_always_equal
	= typename __detected_or_t<is_empty<_Alloc>, __equal, _Alloc>::type;

template<typename _Tp>
	using rebind_alloc = __alloc_rebind<_Alloc, _Tp>;
      template<typename _Tp>
	using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;

private:
      template<typename _Alloc2>
	static constexpr auto
	_S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint, int)
	-> decltype(__a.allocate(__n, __hint))
	{ return __a.allocate(__n, __hint); }

template<typename _Alloc2>
	static constexpr pointer
	_S_allocate(_Alloc2& __a, size_type __n, const_void_pointer, ...)
	{ return __a.allocate(__n); }

template<typename _Alloc2, typename _Tp>
	static _GLIBCXX14_CONSTEXPR auto
	_S_destroy(_Alloc2& __a, _Tp* __p, int)
	noexcept(noexcept(__a.destroy(__p)))
	-> decltype(__a.destroy(__p))
	{ __a.destroy(__p); }

template<typename _Alloc2, typename _Tp>
	static _GLIBCXX14_CONSTEXPR void
	_S_destroy(_Alloc2&, _Tp* __p, ...)
	noexcept(std::is_nothrow_destructible<_Tp>::value)
	{ std::_Destroy(__p); }

template<typename _Alloc2>
	static constexpr auto
	_S_max_size(_Alloc2& __a, int)
	-> decltype(__a.max_size())
	{ return __a.max_size(); }

template<typename _Alloc2>
	static constexpr size_type
	_S_max_size(_Alloc2&, ...)
	{
	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
	  // 2466. allocator_traits::max_size() default behavior is incorrect
	  return __gnu_cxx::__numeric_traits<size_type>::__max
	    / sizeof(value_type);
	}

template<typename _Alloc2>
	static constexpr auto
	_S_select(_Alloc2& __a, int)
	-> decltype(__a.select_on_container_copy_construction())
	{ return __a.select_on_container_copy_construction(); }

template<typename _Alloc2>
	static constexpr _Alloc2
	_S_select(_Alloc2& __a, ...)
	{ return __a; }

public:

/**
       *  @brief  Allocate memory.
       *  @param  __a  An allocator.
       *  @param  __n  The number of objects to allocate space for.
       *
       *  Calls @c a.allocate(n)
      */
      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
      allocate(_Alloc& __a, size_type __n)
      { return __a.allocate(__n); }

/**
       *  @brief  Allocate memory.
       *  @param  __a  An allocator.
       *  @param  __n  The number of objects to allocate space for.
       *  @param  __hint Aid to locality.
       *  @return Memory of suitable size and alignment for @a n objects
       *          of type @c value_type
       *
       *  Returns <tt> a.allocate(n, hint) </tt> if that expression is
       *  well-formed, otherwise returns @c a.allocate(n)
      */
      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
      allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
      { return _S_allocate(__a, __n, __hint, 0); }

/**
       *  @brief  Deallocate memory.
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to the memory to deallocate.
       *  @param  __n  The number of objects space was allocated for.
       *
       *  Calls <tt> a.deallocate(p, n) </tt>
      */
      static _GLIBCXX20_CONSTEXPR void
      deallocate(_Alloc& __a, pointer __p, size_type __n)
      { __a.deallocate(__p, __n); }

/**
       *  @brief  Construct an object of type `_Tp`
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to memory of suitable size and alignment for Tp
       *  @param  __args Constructor arguments.
       *
       *  Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
       *  if that expression is well-formed, otherwise uses placement-new
       *  to construct an object of type @a _Tp at location @a __p from the
       *  arguments @a __args...
      */
      template<typename _Tp, typename... _Args>
	static _GLIBCXX20_CONSTEXPR
	__enable_if_t<__can_construct<_Alloc, _Tp, _Args...>>
	construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
	noexcept(_S_nothrow_construct<_Tp, _Args...>())
	{
	  if constexpr (__has_construct<_Alloc, _Tp, _Args...>)
	    __a.construct(__p, std::forward<_Args>(__args)...);
	  else
	    std::_Construct(__p, std::forward<_Args>(__args)...);
	}

/**
       *  @brief  Destroy an object of type @a _Tp
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to the object to destroy
       *
       *  Calls @c __a.destroy(__p) if that expression is well-formed,
       *  otherwise calls @c __p->~_Tp()
      */
      template<typename _Tp>
	static _GLIBCXX20_CONSTEXPR void
	destroy(_Alloc& __a, _Tp* __p)
	noexcept(noexcept(_S_destroy(__a, __p, 0)))
	{ _S_destroy(__a, __p, 0); }

/**
       *  @brief  The maximum supported allocation size
       *  @param  __a  An allocator.
       *  @return @c __a.max_size() or @c numeric_limits<size_type>::max()
       *
       *  Returns @c __a.max_size() if that expression is well-formed,
       *  otherwise returns @c numeric_limits<size_type>::max()
      */
      static _GLIBCXX20_CONSTEXPR size_type
      max_size(const _Alloc& __a) noexcept
      { return _S_max_size(__a, 0); }

/**
       *  @brief  Obtain an allocator to use when copying a container.
       *  @param  __rhs  An allocator.
       *  @return @c __rhs.select_on_container_copy_construction() or @a __rhs
       *
       *  Returns @c __rhs.select_on_container_copy_construction() if that
       *  expression is well-formed, otherwise returns @a __rhs
      */
      static _GLIBCXX20_CONSTEXPR _Alloc
      select_on_container_copy_construction(const _Alloc& __rhs)
      { return _S_select(__rhs, 0); }

private:
#if __cpp_constexpr >= 201304 // >= C++14
      template<typename _Tp, typename... _Args>
	static constexpr bool
	_S_nothrow_construct(_Alloc* __a = nullptr, _Tp* __p = nullptr)
	{
	  if constexpr (__has_construct<_Alloc, _Tp, _Args...>)
	    return noexcept(__a->construct(__p, std::declval<_Args>()...));
	  else
	    return __is_nothrow_new_constructible<_Tp, _Args...>;
	}
#else
      template<typename _Tp, typename... _Args>
	static constexpr
	__enable_if_t<__has_construct<_Alloc, _Tp, _Args...>, bool>
	_S_nothrow_construct(_Alloc* __a = nullptr, _Tp* __p = nullptr)
	{ return noexcept(__a->construct(__p, std::declval<_Args>()...)); }

template<typename _Tp, typename... _Args>
	static constexpr
	__enable_if_t<!__has_construct<_Alloc, _Tp, _Args...>, bool>
	_S_nothrow_construct(_Alloc* = nullptr, _Tp* __p = nullptr)
	{ return __is_nothrow_new_constructible<_Tp, _Args...>; }
#endif
    };
#pragma GCC diagnostic pop

#if _GLIBCXX_HOSTED
  /**
   * @brief  Partial specialization for `std::allocator`
   * @headerfile memory
   * @ingroup allocators
   * @since C++11
   * @see std::allocator_traits
  */
  template<typename _Tp>
    struct allocator_traits<allocator<_Tp>>
    {
      /// The allocator type
      using allocator_type = allocator<_Tp>;

/// The allocated type
      using value_type = _Tp;

/// The allocator's pointer type.
      using pointer = _Tp*;

/// The allocator's const pointer type.
      using const_pointer = const _Tp*;

/// The allocator's void pointer type.
      using void_pointer = void*;

/// The allocator's const void pointer type.
      using const_void_pointer = const void*;

/// The allocator's difference type
      using difference_type = std::ptrdiff_t;

/// The allocator's size type
      using size_type = std::size_t;

/// How the allocator is propagated on copy assignment
      using propagate_on_container_copy_assignment = false_type;

/// How the allocator is propagated on move assignment
      using propagate_on_container_move_assignment = true_type;

/// How the allocator is propagated on swap
      using propagate_on_container_swap = false_type;

/// Whether all instances of the allocator type compare equal.
      using is_always_equal = true_type;

template<typename _Up>
	using rebind_alloc = allocator<_Up>;

template<typename _Up>
	using rebind_traits = allocator_traits<allocator<_Up>>;

/**
       *  @brief  Allocate memory.
       *  @param  __a  An allocator.
       *  @param  __n  The number of objects to allocate space for.
       *
       *  Calls @c a.allocate(n)
      */
      [[__nodiscard__,__gnu__::__always_inline__]]
      static _GLIBCXX20_CONSTEXPR pointer
      allocate(allocator_type& __a, size_type __n)
      { return __a.allocate(__n); }

/**
       *  @brief  Allocate memory.
       *  @param  __a  An allocator.
       *  @param  __n  The number of objects to allocate space for.
       *  @param  __hint Aid to locality.
       *  @return Memory of suitable size and alignment for @a n objects
       *          of type @c value_type
       *
       *  Returns <tt> a.allocate(n, hint) </tt>
      */
      [[__nodiscard__,__gnu__::__always_inline__]]
      static _GLIBCXX20_CONSTEXPR pointer
      allocate(allocator_type& __a, size_type __n,
	       [[maybe_unused]] const_void_pointer __hint)
      {
#if __cplusplus <= 201703L
	return __a.allocate(__n, __hint);
#else
	return __a.allocate(__n);
#endif
      }

/**
       *  @brief  Deallocate memory.
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to the memory to deallocate.
       *  @param  __n  The number of objects space was allocated for.
       *
       *  Calls <tt> a.deallocate(p, n) </tt>
      */
      [[__gnu__::__always_inline__]]
      static _GLIBCXX20_CONSTEXPR void
      deallocate(allocator_type& __a, pointer __p, size_type __n)
      { __a.deallocate(__p, __n); }

/**
       *  @brief  Construct an object of type `_Up`
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to memory of suitable size and alignment for
       *	       an object of type `_Up`.
       *  @param  __args Constructor arguments.
       *
       *  Calls `__a.construct(__p, std::forward<_Args>(__args)...)`
       *  in C++11, C++14 and C++17. Changed in C++20 to call
       *  `std::construct_at(__p, std::forward<_Args>(__args)...)` instead.
      */
      template<typename _Up, typename... _Args>
	[[__gnu__::__always_inline__]]
	static _GLIBCXX20_CONSTEXPR void
	construct(allocator_type& __a __attribute__((__unused__)),
		  _Up* __p, _Args&&... __args)
#if __cplusplus <= 201703L
	noexcept(noexcept(__a.construct(__p, std::forward<_Args>(__args)...)))
#else
	noexcept(__is_nothrow_new_constructible<_Up, _Args...>)
#endif
	{
#if __cplusplus <= 201703L
	  __a.construct(__p, std::forward<_Args>(__args)...);
#elif __cpp_constexpr_dynamic_alloc // >= C++20
	  std::construct_at(__p, std::forward<_Args>(__args)...);
#else
	  std::_Construct(__p, std::forward<_Args>(__args)...);
#endif
	}

/**
       *  @brief  Destroy an object of type @a _Up
       *  @param  __a  An allocator.
       *  @param  __p  Pointer to the object to destroy
       *
       *  Calls @c __a.destroy(__p).
      */
      template<typename _Up>
	[[__gnu__::__always_inline__]]
	static _GLIBCXX20_CONSTEXPR void
	destroy(allocator_type& __a __attribute__((__unused__)), _Up* __p)
	noexcept(is_nothrow_destructible<_Up>::value)
	{
#if __cplusplus <= 201703L
	  __a.destroy(__p);
#else
	  std::destroy_at(__p);
#endif
	}

/**
       *  @brief  The maximum supported allocation size
       *  @param  __a  An allocator.
       *  @return @c __a.max_size()
      */
      [[__gnu__::__always_inline__]]
      static _GLIBCXX20_CONSTEXPR size_type
      max_size(const allocator_type& __a __attribute__((__unused__))) noexcept
      {
#if __cplusplus <= 201703L
	return __a.max_size();
#else
	return size_t(-1) / sizeof(value_type);
#endif
      }

/**
       *  @brief  Obtain an allocator to use when copying a container.
       *  @param  __rhs  An allocator.
       *  @return @c __rhs
      */
      [[__gnu__::__always_inline__]]
      static _GLIBCXX20_CONSTEXPR allocator_type
      select_on_container_copy_construction(const allocator_type& __rhs)
      { return __rhs; }
    };

/**
   * @brief  Explicit specialization for `std::allocator<void>`
   * @headerfile memory
   * @ingroup allocators
   * @since C++11
   * @see std::allocator_traits
  */
  template<>
    struct allocator_traits<allocator<void>>
    {
      /// The allocator type
      using allocator_type = allocator<void>;

/// The allocated type
      using value_type = void;

/// The allocator's pointer type.
      using pointer = void*;

/// The allocator's const pointer type.
      using const_pointer = const void*;