标准库标头 <memory>

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C++
 
标准库头
 

此头文件是动态内存管理库的一部分。

包含

(C++20)
三路比较运算符支持

类

指针特征
(C++11)
提供关于指针式类型的信息
(类模板)
垃圾收集器支持
(C++11)(C++23 移除)
列出指针安全模式
(枚举)
分配器
默认的分配器
(类模板)
(C++11)
提供关于分配器类型的信息
(类模板)
(C++23)
记录由 allocate_at_least 分配的存储的地址与实际大小
(类模板)
(C++11)
检查指定的类型是否支持使用分配器的构造
(类模板)
未初始化存储
(C++17 弃用)(C++20 移除)
允许标准算法存储结果于未初始化内存的迭代器
(类模板)
智能指针
(C++11)
拥有独有对象所有权语义的智能指针
(类模板)
(C++11)
拥有共享对象所有权语义的智能指针
(类模板)
(C++11)
到 std::shared_ptr 所管理对象的弱引用
(类模板)
(C++11 弃用)(C++17 移除)
拥有严格对象所有权语义的智能指针
(类模板)
智能指针适配器
(C++23)
与外来指针设置器交互，并在析构时重设智能指针
(类模板)
(C++23)
与外来指针设置器交互，从智能指针获得初始指针值，并在析构时重设
(类模板)
用于组合类设计的类型
(C++26)
包含动态分配对象的具有类似值语义的包装器
(类模板)
(C++26)
包含动态分配对象的带有类似值语义的多态包装器
(类模板)
辅助类
(C++20)
原子共享指针
(类模板特化)
(C++20)
原子弱指针
(类模板特化)
(C++11)
提供共享指针和弱指针的基于所有者的混合类型排序
(类模板)
(C++11)
允许对象创建指代自身的 shared_ptr
(类模板)
(C++11)
访问指向已销毁对象的 weak_ptr 时抛出的异常
(类)
(C++11)
unique_ptr 的默认删除器
(类模板)
(C++11)
std::unique_ptr 的散列支持
(类模板特化)
(C++11)
std::shared_ptr 的散列支持
(类模板特化)
前置声明
在标头 <functional> 定义
(C++11)
散列函数对象
(类模板)
在标头 <atomic> 定义
(C++11)
atomic 类模板及其针对布尔、整数、浮点数(C++20 起)和指针类型的特化
(类模板)

标签

(C++11)
用于选择具分配器的构造函数的标签
(标签)

函数

使用分配器的构造
(C++20)
准备好与给定类型所要求的使用分配器构造的形式向匹配的实参列表
(函数模板)
(C++20)
以使用分配器构造的手段创建给类型的对象
(函数模板)
(C++20)
以使用分配器构造的手段在指定的内存位置创建给定类型的对象
(函数模板)
杂项
(C++20)
从指针式类型获得裸指针
(函数模板)
(C++11)
获得对象的实际地址，即使其重载了 & 运算符
(函数模板)
(C++11)
对齐缓冲区中的指针
(函数)
(C++20)
告知编译器指针已对齐
(函数模板)
(C++26)
检查指针是否指向至少具有给定对齐值的对象
(函数模板)
显式生存期管理
(C++23)
在给定的存储上创建对象并复用对象表示
(函数模板)
垃圾收集器支持
(C++11)(C++23 移除)
声明一个对象不能被回收
(函数)
(C++11)(C++23 移除)
声明一个对象可以被回收
(函数模板)
(C++11)(C++23 移除)
声明该内存区域不含可追踪指针
(函数)
(C++11)(C++23 移除)
取消 std::declare_no_pointers 的效果
(函数)
(C++11)(C++23 移除)
返回当前的指针安全模式
(函数)
未初始化存储
复制范围中对象到未初始化内存
(函数模板)
(C++11)
复制若干对象到未初始化内存
(函数模板)
复制一个对象到范围所定义的未初始化内存
(函数模板)
复制一个对象到起点和数量所定义的未初始化内存
(函数模板)
(C++17)
移动范围中对象到未初始化内存
(函数模板)
(C++17)
移动若干对象到未初始化内存
(函数模板)
(C++17)
在范围所定义的未初始化内存中用默认初始化构造对象
(函数模板)
(C++17)
在起点和数量所定义的未初始化内存中用默认初始化构造对象
(函数模板)
(C++17)
在范围所定义的未初始化内存中用值初始化构造对象
(函数模板)
(C++17)
在起点和数量所定义的未初始化内存中用值初始化构造对象
(函数模板)
(C++20)
在给定地址创建对象
(函数模板)
(C++17)
销毁给定地址的对象
(函数模板)
(C++17)
销毁范围中的对象
(函数模板)
(C++17)
销毁范围中若干对象
(函数模板)
(C++17 弃用)(C++20 移除)
获得未初始化存储
(函数模板)
(C++17 弃用)(C++20 移除)
释放未初始化存储
(函数模板)
智能指针非成员操作
(C++14)(C++20)
创建管理一个新对象的独占指针
(函数模板)
(C++20 移除)(C++20)
与另一个 unique_ptr 或 nullptr 进行比较
(函数模板)
(C++20)
创建管理一个新对象的共享指针
(函数模板)
(C++20)
创建管理一个用分配器分配的新对象的共享指针
(函数模板)
(C++17)
应用 static_cast、dynamic_cast、const_cast 或 reinterpret_cast 到被存储指针
(函数模板)
返回指定类型中的删除器，若其拥有
(函数模板)
(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20)
与另一个 shared_ptr 或 nullptr 进行比较
(函数模板)
输出存储的指针的值到输出流
(函数模板)
(C++20)
输出被管理指针的值到输出流
(函数模板)
(C++11)
特化 std::swap 算法
(函数模板)
(C++11)
特化 std::swap 算法
(函数模板)
(C++11)
特化 std::swap 算法
(函数模板)
智能指针适配器创建
(C++23)
以关联的智能指针和重设参数创建 out_ptr_t
(函数模板)
(C++23)
以关联的智能指针和重设参数创建 inout_ptr_t
(函数模板)
(C++20 弃用)(C++26 移除)
为 std::shared_ptr 特化的原子操作
(函数模板)

函数式实体

在命名空间 std::ranges 定义
未初始化存储
(C++20)
复制范围中对象到未初始化内存
(算法函数对象)
(C++20)
复制若干对象到未初始化内存
(算法函数对象)
(C++20)
复制一个对象到范围所定义的未初始化内存
(算法函数对象)
(C++20)
复制一个对象到起点和数量所定义的未初始化内存
(算法函数对象)
(C++20)
移动范围中对象到未初始化内存
(算法函数对象)
(C++20)
移动若干对象到未初始化内存
(算法函数对象)
(C++20)
在范围所定义的未初始化内存中用默认初始化构造对象
(算法函数对象)
(C++20)
在起点和数量所定义的未初始化内存中用默认初始化构造对象
(算法函数对象)
(C++20)
在范围所定义的未初始化内存中用值初始化构造对象
(算法函数对象)
(C++20)
在起点和数量所定义的未初始化内存中用值初始化构造对象
(算法函数对象)
(C++20)
在给定地址创建对象
(算法函数对象)
(C++20)
销毁给定地址的对象
(算法函数对象)
(C++20)
销毁范围中的对象
(算法函数对象)
(C++20)
销毁范围中若干对象
(算法函数对象)

概要

#include <compare>
 
namespace std {
  // 指针特征
  template<class Ptr>
  struct pointer_traits; // 独立
  template<class T>
  struct pointer_traits<T*>; // 独立
 
  // 指针转换
  template<class T>
  constexpr T* to_address(T* p) noexcept; // 独立
  template<class Ptr>
  constexpr auto to_address(const Ptr& p) noexcept; // 独立
 
  // 指针对齐
  void* align(size_t alignment, size_t size, void*& ptr, size_t& space); // 独立
  template<size_t N, class T>
  constexpr T* assume_aligned(T* ptr); // 独立
  template<size_t Alignment, class T>
  bool is_sufficiently_aligned(T* ptr);
 
  // 显式生存期管理
  template<class T>
  T* start_lifetime_as(void* p) noexcept; // 独立
  template<class T>
  const T* start_lifetime_as(const void* p) noexcept; // 独立
  template<class T>
  volatile T* start_lifetime_as(volatile void* p) noexcept; // 独立
  template<class T>
  const volatile T* start_lifetime_as(const volatile void* p) noexcept; // 独立
  template<class T>
  T* start_lifetime_as_array(void* p, size_t n) noexcept; // 独立
  template<class T>
  const T* start_lifetime_as_array(const void* p, size_t n) noexcept; // 独立
  template<class T>
  volatile T* start_lifetime_as_array(volatile void* p,
                                      size_t n) noexcept; // 独立
  template<class T>
  const volatile T* start_lifetime_as_array(const volatile void* p, // 独立
                                            size_t n) noexcept;
  template<class T>
  T* trivially_relocate(T* first, T* last, T* result); // 独立
  template<class T>
  constexpr T* relocate(T* first, T* last, T* result); // 独立
 
  // 分配器实参标签
  struct allocator_arg_t
  {
    explicit allocator_arg_t() = default;
  };                                                // 独立
  inline constexpr allocator_arg_t allocator_arg{}; // 独立
 
  // uses_allocator
  template<class T, class Alloc>
  struct uses_allocator; // 独立
 
  // uses_allocator
  template<class T, class Alloc>
  constexpr bool uses_allocator_v = uses_allocator<T, Alloc>::value; // 独立
 
  // uses-allocator 构造
  template<class T, class Alloc, class... Args>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  Args&&... args) noexcept;
  template<class T, class Alloc, class Tuple1, class Tuple2>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  piecewise_construct_t,
                                                  Tuple1&& x,
                                                  Tuple2&& y) noexcept;
  template<class T, class Alloc>
  constexpr auto uses_allocator_construction_args(
    const Alloc& alloc) noexcept; // 独立
  template<class T, class Alloc, class U, class V>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  U&& u,
                                                  V&& v) noexcept;
  template<class T, class Alloc, class U, class V>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  pair<U, V>& pr) noexcept;
  template<class T, class Alloc, class U, class V>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  const pair<U, V>& pr) noexcept;
  template<class T, class Alloc, class U, class V>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  pair<U, V>&& pr) noexcept;
  template<class T, class Alloc, class U, class V>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  const pair<U, V>&& pr) noexcept;
  template<class T, class Alloc, /*pair-like*/ P>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  P&& p) noexcept;
  template<class T, class Alloc, class U>
  constexpr auto uses_allocator_construction_args(const Alloc& alloc, // 独立
                                                  U&& u) noexcept;
  template<class T, class Alloc, class... Args>
  constexpr T make_obj_using_allocator(const Alloc& alloc,
                                       Args&&... args); // 独立
  template<class T, class Alloc, class... Args>
  constexpr T* uninitialized_construct_using_allocator(T* p, // 独立
                                                       const Alloc& alloc,
                                                       Args&&... args);
 
  // 分配器特征
  template<class Alloc>
  struct allocator_traits; // 独立
 
  template<class Pointer, class SizeType = size_t>
  struct allocation_result
  { // 独立
    Pointer ptr;
    SizeType count;
  };
 
  // 默认分配器
  template<class T>
  class allocator;
  template<class T, class U>
  constexpr bool operator==(const allocator<T>&, const allocator<U>&) noexcept;
 
  // addressof
  template<class T>
  constexpr T* addressof(T& r) noexcept; // 独立
  template<class T>
  const T* addressof(const T&&) = delete; // 独立
 
  // 专用算法
  // 特殊内存概念
  template<class I>
  concept no-throw-input-iterator = /* 见描述 */; // 仅用于阐述
  template<class I>
  concept no-throw-forward-iterator = /* 见描述 */; // 仅用于阐述
  template<class S, class I>
  concept no-throw-sentinel-for = /* 见描述 */; // 仅用于阐述
  template<class R>
  concept no-throw-input-range = /* 见描述 */; // 仅用于阐述
  template<class R>
  concept no-throw-forward-range = /* 见描述 */; // 仅用于阐述
 
  template<class NoThrowForwardIter>
  constexpr void uninitialized_default_construct(NoThrowForwardIter first, // 独立
                                                 NoThrowForwardIter last);
  template<class ExecutionPolicy, class NoThrowForwardIter>
  void uninitialized_default_construct(ExecutionPolicy&& exec, // 独立或弃置
                                       NoThrowForwardIter first,
                                       NoThrowForwardIter last);
  template<class NoThrowForwardIter, class Size>
  constexpr NoThrowForwardIter uninitialized_default_construct_n(NoThrowForwardIter first,
                                                                 Size n); // 独立
  template<class ExecutionPolicy, class NoThrowForwardIter, class Size>
  NoThrowForwardIter uninitialized_default_construct_n(
    ExecutionPolicy&& exec, // 独立或弃置
    NoThrowForwardIter first,
    Size n);
 
  namespace ranges {
    template<no-throw-forward-iterator I, no-throw-sentinel-for<I> S>
      requires default_initializable<iter_value_t<I>>
    constexpr I uninitialized_default_construct(I first, S last); // 独立
    template<no-throw-forward-range R>
      requires default_initializable<range_value_t<R>>
    constexpr borrowed_iterator_t<R> uninitialized_default_construct(
      R&& r); // 独立
 
    template<no-throw-forward-iterator I>
      requires default_initializable<iter_value_t<I>>
    constexpr I uninitialized_default_construct_n(I first, // 独立
                                                  iter_difference_t<I> n);
  }
 
  template<class NoThrowForwardIter>
  constexpr void uninitialized_value_construct(NoThrowForwardIter first, // 独立
                                               NoThrowForwardIter last);
  template<class ExecutionPolicy, class NoThrowForwardIter>
  void uninitialized_value_construct(ExecutionPolicy&& exec, // 独立或弃置
                                     NoThrowForwardIter first,
                                     NoThrowForwardIter last);
  template<class NoThrowForwardIter, class Size>
  constexpr NoThrowForwardIter uninitialized_value_construct_n(NoThrowForwardIter first,
                                                               Size n); // 独立
  template<class ExecutionPolicy, class NoThrowForwardIter, class Size>
  NoThrowForwardIter uninitialized_value_construct_n(
    ExecutionPolicy&& exec, // 独立或弃置
    NoThrowForwardIter first,
    Size n);
 
  namespace ranges {
    template<no-throw-forward-iterator I, no-throw-sentinel-for<I> S>
      requires default_initializable<iter_value_t<I>>
    constexpr I uninitialized_value_construct(I first, S last); // 独立
    template<no-throw-forward-range R>
      requires default_initializable<range_value_t<R>>
    constexpr borrowed_iterator_t<R> uninitialized_value_construct(R&& r); // 独立
 
    template<no-throw-forward-iterator I>
      requires default_initializable<iter_value_t<I>>
    constexpr I uninitialized_value_construct_n(I first, // 独立
                                                iter_difference_t<I> n);
  }
 
  template<class InputIter, class NoThrowForwardIter>
  constexpr NoThrowForwardIter uninitialized_copy(InputIter first, // 独立
                                                  InputIter last,
                                                  NoThrowForwardIter result);
  template<class ExecutionPolicy, class ForwardIter, class NoThrowForwardIter>
  NoThrowForwardIter uninitialized_copy(ExecutionPolicy&& exec, // 独立或弃置
                                        ForwardIter first,
                                        ForwardIter last,
                                        NoThrowForwardIter result);
  template<class InputIter, class Size, class NoThrowForwardIter>
  constexpr NoThrowForwardIter uninitialized_copy_n(InputIter first, // 独立
                                                    Size n,
                                                    NoThrowForwardIter result);
  template<class ExecutionPolicy,
           class ForwardIter,
           class Size,
           class NoThrowForwardIter>
  NoThrowForwardIter uninitialized_copy_n(ExecutionPolicy&& exec, // 独立或弃置
                                          ForwardIter first,
                                          Size n,
                                          NoThrowForwardIter result);
 
  namespace ranges {
    template<class I, class O>
    using uninitialized_copy_result = in_out_result<I, O>; // 独立
    template<input_iterator I,
             sentinel_for<I> S1,
             no-throw-forward-iterator O,
             no-throw-sentinel-for<O> S2>
      requires constructible_from<iter_value_t<O>, iter_reference_t<I>>
    constexpr uninitialized_copy_result<I, O>
    uninitialized_copy(I ifirst, S1 ilast, O ofirst, S2 olast); // 独立
    template<input_range IR, no-throw-forward-range OR>
      requires constructible_from<range_value_t<OR>, range_reference_t<IR>>
    constexpr uninitialized_copy_result<borrowed_iterator_t<IR>, borrowed_iterator_t<OR>>
    uninitialized_copy(IR&& in_range, OR&& out_range); // 独立
 
    template<class I, class O>
    using uninitialized_copy_n_result = in_out_result<I, O>; // 独立
    template<input_iterator I,
             no-throw-forward-iterator O,
             no-throw-sentinel-for<O> S>
      requires constructible_from<iter_value_t<O>, iter_reference_t<I>>
    constexpr uninitialized_copy_n_result<I, O> uninitialized_copy_n(
      I ifirst,
      iter_difference_t<I> n, // 独立
      O ofirst,
      S olast);
  }
 
  template<class InputIter, class NoThrowForwardIter>
  constexpr NoThrowForwardIter uninitialized_move(InputIter first, // 独立
                                                  InputIter last,
                                                  NoThrowForwardIter result);
  template<class ExecutionPolicy, class ForwardIter, class NoThrowForwardIter>
  NoThrowForwardIter uninitialized_move(ExecutionPolicy&& exec, // 独立或弃置
                                        ForwardIter first,
                                        ForwardIter last,
                                        NoThrowForwardIter result);
  template<class InputIter, class Size, class NoThrowForwardIter>
  constexpr pair<InputIter, NoThrowForwardIter> uninitialized_move_n(
    InputIter first,
    Size n, // 独立
    NoThrowForwardIter result);
  template<class ExecutionPolicy, class ForwardIter, class Size, class NoThrowForwardIter>
  pair<ForwardIter, NoThrowForwardIter> uninitialized_move_n(
    ExecutionPolicy&& exec, // 独立或弃置
    ForwardIter first,
    Size n,
    NoThrowForwardIter result);
 
  namespace ranges {
    template<class I, class O>
    using uninitialized_move_result = in_out_result<I, O>; // 独立
    template<input_iterator I,
             sentinel_for<I> S1,
             no-throw-forward-iterator O,
             no-throw-sentinel-for<O> S2>
      requires constructible_from<iter_value_t<O>, iter_rvalue_reference_t<I>>
    constexpr uninitialized_move_result<I, O>
    uninitialized_move(I ifirst, S1 ilast, O ofirst, S2 olast); // 独立
    template<input_range IR, no-throw-forward-range OR>
      requires constructible_from<range_value_t<OR>, range_rvalue_reference_t<IR>>
    constexpr uninitialized_move_result<borrowed_iterator_t<IR>, borrowed_iterator_t<OR>>
    uninitialized_move(IR&& in_range, OR&& out_range); // 独立
 
    template<class I, class O>
    using uninitialized_move_n_result = in_out_result<I, O>; // 独立
    template<input_iterator I,
             no-throw-forward-iterator O,
             no-throw-sentinel-for<O> S>
      requires constructible_from<iter_value_t<O>, iter_rvalue_reference_t<I>>
    constexpr uninitialized_move_n_result<I, O> uninitialized_move_n(
      I ifirst,
      iter_difference_t<I> n, // 独立
      O ofirst,
      S olast);
  }
 
  template<class NoThrowForwardIter, class T>
  constexpr void uninitialized_fill(NoThrowForwardIter first, // 独立
                                    NoThrowForwardIter last,
                                    const T& x);
  template<class ExecutionPolicy, class NoThrowForwardIter, class T>
  void uninitialized_fill(ExecutionPolicy&& exec, // 独立或弃置
                          NoThrowForwardIter first,
                          NoThrowForwardIter last,
                          const T& x);
  template<class NoThrowForwardIter, class Size, class T>
  constexpr NoThrowForwardIter uninitialized_fill_n(NoThrowForwardIter first,
                                                    Size n,
                                                    const T& x); // 独立
  template<class ExecutionPolicy, class NoThrowForwardIter, class Size, class T>
  NoThrowForwardIter uninitialized_fill_n(ExecutionPolicy&& exec, // 独立或弃置
                                          NoThrowForwardIter first,
                                          Size n,
                                          const T& x);
 
  namespace ranges {
    template<no-throw-forward-iterator I, no-throw-sentinel-for<I> S, class T>
      requires constructible_from<iter_value_t<I>, const T&>
    constexpr I uninitialized_fill(I first, S last, const T& x); // 独立
    template<no-throw-forward-range R, class T>
      requires constructible_from<range_value_t<R>, const T&>
    constexpr borrowed_iterator_t<R> uninitialized_fill(R&& r,
                                                        const T& x); // 独立
 
    template<no-throw-forward-iterator I, class T>
      requires constructible_from<iter_value_t<I>, const T&>
    constexpr I uninitialized_fill_n(I first, // 独立
                                     iter_difference_t<I> n,
                                     const T& x);
  }
 
  // construct_at
  template<class T, class... Args>
  constexpr T* construct_at(T* location, Args&&... args); // 独立
 
  namespace ranges {
    template<class T, class... Args>
    constexpr T* construct_at(T* location, Args&&... args); // 独立
  }
 
  // destroy
  template<class T>
  constexpr void destroy_at(T* location); // 独立
  template<class NoThrowForwardIter>
  constexpr void destroy(NoThrowForwardIter first, // 独立
                         NoThrowForwardIter last);
  template<class ExecutionPolicy, class NoThrowForwardIter>
  void destroy(ExecutionPolicy&& exec, // 独立或弃置
               NoThrowForwardIter first,
               NoThrowForwardIter last);
  template<class NoThrowForwardIter, class Size>
  constexpr NoThrowForwardIter destroy_n(NoThrowForwardIter first, // 独立
                                         Size n);
  template<class ExecutionPolicy, class NoThrowForwardIter, class Size>
  NoThrowForwardIter destroy_n(ExecutionPolicy&& exec, // 独立或弃置
                               NoThrowForwardIter first,
                               Size n);
 
  namespace ranges {
    template<destructible T>
    constexpr void destroy_at(T* location) noexcept; // 独立
 
    template<no-throw-input-iterator I, no-throw-sentinel-for<I> S>
      requires destructible<iter_value_t<I>>
    constexpr I destroy(I first, S last) noexcept; // 独立
    template<no-throw-input-range R>
      requires destructible<range_value_t<R>>
    constexpr borrowed_iterator_t<R> destroy(R&& r) noexcept; // 独立
 
    template<no-throw-input-iterator I>
      requires destructible<iter_value_t<I>>
    constexpr I destroy_n(I first, iter_difference_t<I> n) noexcept; // 独立
  }
 
  // 类模板 unique_ptr
  template<class T>
  struct default_delete; // 独立
  template<class T>
  struct default_delete<T[]>; // 独立
  template<class T, class D = default_delete<T>>
  class unique_ptr; // 独立
  template<class T, class D>
  class unique_ptr<T[], D>; // 独立
 
  template<class T, class... Args>
  constexpr unique_ptr<T> make_unique(Args&&... args); // T 非数组
  template<class T>
  constexpr unique_ptr<T> make_unique(size_t n); // T 是 U[]
  template<class T, class... Args>
  /* 未指定 */ make_unique(Args&&...) = delete; // T 是 U[N]
 
  template<class T>
  constexpr unique_ptr<T> make_unique_for_overwrite(); // T 非数组
  template<class T>
  constexpr unique_ptr<T> make_unique_for_overwrite(size_t n); // T 是 U[]
  template<class T, class... Args>
  /* 未指定 */ make_unique_for_overwrite(Args&&...) = delete; // T 是 U[N]
 
  template<class T, class D>
  constexpr void swap(unique_ptr<T, D>& x, unique_ptr<T, D>& y) noexcept; // 独立
 
  template<class T1, class D1, class T2, class D2>
  constexpr bool operator==(const unique_ptr<T1, D1>& x, // 独立
                            const unique_ptr<T2, D2>& y);
  template<class T1, class D1, class T2, class D2>
  bool operator<(const unique_ptr<T1, D1>& x,
                 const unique_ptr<T2, D2>& y); // 独立
  template<class T1, class D1, class T2, class D2>
  bool operator>(const unique_ptr<T1, D1>& x,
                 const unique_ptr<T2, D2>& y); // 独立
  template<class T1, class D1, class T2, class D2>
  bool operator<=(const unique_ptr<T1, D1>& x,
                  const unique_ptr<T2, D2>& y); // 独立
  template<class T1, class D1, class T2, class D2>
  bool operator>=(const unique_ptr<T1, D1>& x,
                  const unique_ptr<T2, D2>& y); // 独立
  template<class T1, class D1, class T2, class D2>
    requires three_way_comparable_with<typename unique_ptr<T1, D1>::pointer,
                                       typename unique_ptr<T2, D2>::pointer>
  compare_three_way_result_t<typename unique_ptr<T1, D1>::pointer,
                             typename unique_ptr<T2, D2>::pointer>
  operator<=>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y); // 独立
 
  template<class T, class D>
  constexpr bool operator==(const unique_ptr<T, D>& x,
                            nullptr_t) noexcept; // 独立
  template<class T, class D>
  constexpr bool operator<(const unique_ptr<T, D>& x, nullptr_t); // 独立
  template<class T, class D>
  constexpr bool operator<(nullptr_t, const unique_ptr<T, D>& y); // 独立
  template<class T, class D>
  constexpr bool operator>(const unique_ptr<T, D>& x, nullptr_t); // 独立
  template<class T, class D>
  constexpr bool operator>(nullptr_t, const unique_ptr<T, D>& y); // 独立
  template<class T, class D>
  constexpr bool operator<=(const unique_ptr<T, D>& x, nullptr_t); // 独立
  template<class T, class D>
  constexpr bool operator<=(nullptr_t, const unique_ptr<T, D>& y); // 独立
  template<class T, class D>
  constexpr bool operator>=(const unique_ptr<T, D>& x, nullptr_t); // 独立
  template<class T, class D>
  constexpr bool operator>=(nullptr_t, const unique_ptr<T, D>& y); // 独立
  template<class T, class D>
    requires three_way_comparable<typename unique_ptr<T, D>::pointer>
  constexpr compare_three_way_result_t<typename unique_ptr<T, D>::pointer> operator<=>(
    const unique_ptr<T, D>& x,
    nullptr_t); // 独立
 
  template<class E, class T, class Y, class D>
  basic_ostream<E, T>& operator<<(basic_ostream<E, T>& os, const unique_ptr<Y, D>& p);
 
  // 类 bad_weak_ptr
  class bad_weak_ptr;
 
  // 类模板 shared_ptr
  template<class T>
  class shared_ptr;
 
  // shared_ptr 创建
  template<class T, class... Args>
  shared_ptr<T> make_shared(Args&&... args); // T 非数组
  template<class T, class A, class... Args>
  shared_ptr<T> allocate_shared(const A& a, Args&&... args); // T 非数组
 
  template<class T>
  shared_ptr<T> make_shared(size_t N); // T 是 U[]
  template<class T, class A>
  shared_ptr<T> allocate_shared(const A& a, size_t N); // T 是 U[]
 
  template<class T>
  shared_ptr<T> make_shared(); // T 是 U[N]
  template<class T, class A>
  shared_ptr<T> allocate_shared(const A& a); // T 是 U[N]
 
  template<class T>
  shared_ptr<T> make_shared(size_t N, const remove_extent_t<T>& u); // T 是 U[]
  template<class T, class A>
  shared_ptr<T> allocate_shared(const A& a,
                                size_t N,
                                const remove_extent_t<T>& u); // T 是 U[]
 
  template<class T>
  shared_ptr<T> make_shared(const remove_extent_t<T>& u); // T 是 U[N]
  template<class T, class A>
  shared_ptr<T> allocate_shared(const A& a, const remove_extent_t<T>& u); // T 是 U[N]
 
  template<class T>
  shared_ptr<T> make_shared_for_overwrite(); // T 不是 U[]
  template<class T, class A>
  shared_ptr<T> allocate_shared_for_overwrite(const A& a); // T 不是 U[]
 
  template<class T>
  shared_ptr<T> make_shared_for_overwrite(size_t N); // T 是 U[]
  template<class T, class A>
  shared_ptr<T> allocate_shared_for_overwrite(const A& a, size_t N); // T 是 U[]
 
  // shared_ptr 比较
  template<class T, class U>
  bool operator==(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
  template<class T, class U>
  strong_ordering operator<=>(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
 
  template<class T>
  bool operator==(const shared_ptr<T>& x, nullptr_t) noexcept;
  template<class T>
  strong_ordering operator<=>(const shared_ptr<T>& x, nullptr_t) noexcept;
 
  // shared_ptr 特化算法
  template<class T>
  void swap(shared_ptr<T>& a, shared_ptr<T>& b) noexcept;
 
  // shared_ptr 转型
  template<class T, class U>
  shared_ptr<T> static_pointer_cast(const shared_ptr<U>& r) noexcept;
  template<class T, class U>
  shared_ptr<T> static_pointer_cast(shared_ptr<U>&& r) noexcept;
  template<class T, class U>
  shared_ptr<T> dynamic_pointer_cast(const shared_ptr<U>& r) noexcept;
  template<class T, class U>
  shared_ptr<T> dynamic_pointer_cast(shared_ptr<U>&& r) noexcept;
  template<class T, class U>
  shared_ptr<T> const_pointer_cast(const shared_ptr<U>& r) noexcept;
  template<class T, class U>
  shared_ptr<T> const_pointer_cast(shared_ptr<U>&& r) noexcept;
  template<class T, class U>
  shared_ptr<T> reinterpret_pointer_cast(const shared_ptr<U>& r) noexcept;
  template<class T, class U>
  shared_ptr<T> reinterpret_pointer_cast(shared_ptr<U>&& r) noexcept;
 
  // shared_ptr get_deleter
  template<class D, class T>
  D* get_deleter(const shared_ptr<T>& p) noexcept;
 
  // shared_ptr I/O
  template<class E, class T, class Y>
  basic_ostream<E, T>& operator<<(basic_ostream<E, T>& os, const shared_ptr<Y>& p);
 
  // 类模板 weak_ptr
  template<class T>
  class weak_ptr;
 
  // weak_ptr 特化算法
  template<class T>
  void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;
 
  // 类模板 owner_less
  template<class T = void>
  struct owner_less;
 
  // 结构体 owner_hash
  struct owner_hash;
 
  // 结构体 owner_equal
  struct owner_equal;
 
  // 类模板 enable_shared_from_this
  template<class T>
  class enable_shared_from_this;
 
  // 散列支持
  template<class T>
  struct hash; // 独立
  template<class T, class D>
  struct hash<unique_ptr<T, D>>; // 独立
  template<class T>
  struct hash<shared_ptr<T>>;
 
  // 原子智能指针
  template<class T>
  struct atomic; // 独立
  template<class T>
  struct atomic<shared_ptr<T>>;
  template<class T>
  struct atomic<weak_ptr<T>>;
 
  // 类模板 out_ptr_t
  template<class Smart, class Pointer, class... Args>
  class out_ptr_t; // 独立
 
  // 函数模板 out_ptr
  template<class Pointer = void, class Smart, class... Args>
  auto out_ptr(Smart& s, Args&&... args); // 独立
 
  // 类模板 inout_ptr_t
  template<class Smart, class Pointer, class... Args>
  class inout_ptr_t; // 独立
 
  // 函数模板 inout_ptr
  template<class Pointer = void, class Smart, class... Args>
  auto inout_ptr(Smart& s, Args&&... args); // 独立
 
  // 类模板 indirect
  template<class T, class Allocator = allocator<T>>
  class indirect;
 
  // 散列支持
  template<class T, class Alloc>
  struct hash<indirect<T, Alloc>>;
 
  // 类模板 polymorphic
  template<class T, class Allocator = allocator<T>>
  class polymorphic;
 
  namespace pmr {
    template<class T>
    using indirect = indirect<T, polymorphic_allocator<T>>;
    template<class T>
    using polymorphic = polymorphic<T, polymorphic_allocator<T>>;
  }
}

辅助概念

注意：这些名字仅用于阐述，它们并不是接口的一部分。

template<class I>
concept no-throw-input-iterator = // 仅用于阐述
  input_iterator<I> &&
  is_lvalue_reference_v<iter_reference_t<I>> &&
  same_as<remove_cvref_t<iter_reference_t<I>>, iter_value_t<I>>;
 
template<class S, class I>
concept no-throw-sentinel-for = sentinel_for<S, I>; // 仅用于阐述
 
template<class R>
concept no-throw-input-range = // 仅用于阐述
  ranges::range<R> &&
  no-throw-input-iterator<ranges::iterator_t<R>> &&
  no-throw-sentinel-for<ranges::sentinel_t<R>, ranges::iterator_t<R>>;
 
template<class I>
concept no-throw-forward-iterator = // 仅用于阐述
  no-throw-input-iterator<I> &&
  forward_iterator<I> &&
  no-throw-sentinel-for<I, I>;
 
template<class R>
concept no-throw-forward-range = // 仅用于阐述
  no-throw-input-range<R> &&
  no-throw-forward-iterator<ranges::iterator_t<R>>;

类模板 std::pointer_traits

namespace std {
  template<class Ptr>
  struct pointer_traits
  {
    /* 见描述 */;
  };
 
  template<class T>
  struct pointer_traits<T*>
  {
    using pointer         = T*;
    using element_type    = T;
    using difference_type = ptrdiff_t;
 
    template<class U>
    using rebind = U*;
 
    static constexpr pointer pointer_to(/* 见描述 */ r) noexcept;
  };
}

类 std::allocator_arg_t

namespace std {
  struct allocator_arg_t { explicit allocator_arg_t() = default; };
  inline constexpr allocator_arg_t allocator_arg{};
}

类模板 std::allocator_traits

namespace std {
  template<class Alloc>
  struct allocator_traits
  {
    using allocator_type                         = Alloc;
 
    using value_type                             = typename Alloc::value_type;
 
    using pointer                                = /* 见描述 */;
    using const_pointer                          = /* 见描述 */;
    using void_pointer                           = /* 见描述 */;
    using const_void_pointer                     = /* 见描述 */;
 
    using difference_type                        = /* 见描述 */;
    using size_type                              = /* 见描述 */;
 
    using propagate_on_container_copy_赋值 = /* 见描述 */;
    using propagate_on_container_move_赋值 = /* 见描述 */;
    using propagate_on_container_swap            = /* 见描述 */;
    using is_always_equal                        = /* 见描述 */;
 
    template<class T>
    using rebind_alloc = /* 见描述 */;
    template<class T>
    using rebind_traits = allocator_traits<rebind_alloc<T>>;
 
    static constexpr pointer allocate(Alloc& a, size_type n);
    static constexpr pointer allocate(Alloc& a, size_type n, const_void_pointer hint);
    static constexpr allocation_result<pointer, size_type> allocate_at_least(Alloc& a,
                                                                             size_type n);
 
    static constexpr void deallocate(Alloc& a, pointer p, size_type n);
 
    template<class T, class... Args>
    static constexpr void construct(Alloc& a, T* p, Args&&... args);
 
    template<class T>
    static constexpr void destroy(Alloc& a, T* p);
 
    static constexpr size_type max_size(const Alloc& a) noexcept;
 
    static constexpr Alloc select_on_container_copy_construction(const Alloc& rhs);
  };
}

类模板 std::allocator

namespace std {
  template<class T>
  class allocator
  {
  public:
    using value_type                             = T;
    using size_type                              = size_t;
    using difference_type                        = ptrdiff_t;
    using propagate_on_container_move_赋值 = true_type;
 
    constexpr allocator() noexcept;
    constexpr allocator(const allocator&) noexcept;
    template<class U>
    constexpr allocator(const allocator<U>&) noexcept;
    constexpr ~allocator();
    constexpr allocator& operator=(const allocator&) = default;
 
    constexpr T* allocate(size_t n);
    constexpr allocation_result<T*> allocate_at_least(size_t n);
    constexpr void deallocate(T* p, size_t n);
  };
}

类模板 std::default_delete

namespace std {
  template<class T>
  struct default_delete
  {
    constexpr default_delete() noexcept = default;
    template<class U>
    constexpr default_delete(const default_delete<U>&) noexcept;
    constexpr void operator()(T*) const;
  };
 
  template<class T>
  struct default_delete<T[]>
  {
    constexpr default_delete() noexcept = default;
    template<class U>
    constexpr default_delete(const default_delete<U[]>&) noexcept;
    template<class U>
    constexpr void operator()(U* ptr) const;
  };
}

类模板 std::unique_ptr

namespace std {
  template<class T, class D = default_delete<T>>
  class unique_ptr
  {
  public:
    using pointer      = /* 见描述 */;
    using element_type = T;
    using deleter_type = D;
 
    // 构造函数
    constexpr unique_ptr() noexcept;
    constexpr explicit unique_ptr(type_identity_t<pointer> p) noexcept;
    constexpr unique_ptr(type_identity_t<pointer> p, /* 见描述 */ d1) noexcept;
    constexpr unique_ptr(type_identity_t<pointer> p, /* 见描述 */ d2) noexcept;
    constexpr unique_ptr(unique_ptr&& u) noexcept;
    constexpr unique_ptr(nullptr_t) noexcept;
    template<class U, class E>
    constexpr unique_ptr(unique_ptr<U, E>&& u) noexcept;
 
    // 析构函数
    constexpr ~unique_ptr();
 
    // 赋值
    constexpr unique_ptr& operator=(unique_ptr&& u) noexcept;
    template<class U, class E>
    constexpr unique_ptr& operator=(unique_ptr<U, E>&& u) noexcept;
    constexpr unique_ptr& operator=(nullptr_t) noexcept;
 
    // 观察器
    constexpr add_lvalue_reference_t<T> operator*() const noexcept(/* 见描述 */);
    constexpr pointer operator->() const noexcept;
    constexpr pointer get() const noexcept;
    constexpr deleter_type& get_deleter() noexcept;
    constexpr const deleter_type& get_deleter() const noexcept;
    constexpr explicit operator bool() const noexcept;
 
    // 修改器
    constexpr pointer release() noexcept;
    constexpr void reset(pointer p = pointer()) noexcept;
    constexpr void swap(unique_ptr& u) noexcept;
 
    // 禁用从左值复制
    unique_ptr(const unique_ptr&)            = delete;
    unique_ptr& operator=(const unique_ptr&) = delete;
  };
 
  template<class T, class D>
  class unique_ptr<T[], D>
  {
  public:
    using pointer      = /* 见描述 */;
    using element_type = T;
    using deleter_type = D;
 
    // 构造函数
    constexpr unique_ptr() noexcept;
    template<class U>
    constexpr explicit unique_ptr(U p) noexcept;
    template<class U>
    constexpr unique_ptr(U p, /* 见描述 */ d) noexcept;
    template<class U>
    constexpr unique_ptr(U p, /* 见描述 */ d) noexcept;
    constexpr unique_ptr(unique_ptr&& u) noexcept;
    template<class U, class E>
    constexpr unique_ptr(unique_ptr<U, E>&& u) noexcept;
    constexpr unique_ptr(nullptr_t) noexcept;
 
    // 析构函数
    constexpr ~unique_ptr();
 
    // 赋值
    constexpr unique_ptr& operator=(unique_ptr&& u) noexcept;
    template<class U, class E>
    constexpr unique_ptr& operator=(unique_ptr<U, E>&& u) noexcept;
    constexpr unique_ptr& operator=(nullptr_t) noexcept;
 
    // 观察器
    constexpr T& operator[](size_t i) const;
    constexpr pointer get() const noexcept;
    constexpr deleter_type& get_deleter() noexcept;
    constexpr const deleter_type& get_deleter() const noexcept;
    constexpr explicit operator bool() const noexcept;
 
    // 修改器
    constexpr pointer release() noexcept;
    template<class U>
    constexpr void reset(U p) noexcept;
    constexpr void reset(nullptr_t = nullptr) noexcept;
    constexpr void swap(unique_ptr& u) noexcept;
 
    // 禁用从左值复制
    unique_ptr(const unique_ptr&)            = delete;
    unique_ptr& operator=(const unique_ptr&) = delete;
  };
}

类 std::bad_weak_ptr

namespace std {
  class bad_weak_ptr : public exception
  {
  public:
    // 用于特殊成员函数的说明
    const char* what() const noexcept override;
  };
}

类模板 std::shared_ptr

namespace std {
  template<class T>
  class shared_ptr
  {
  public:
    using element_type = remove_extent_t<T>;
    using weak_type    = weak_ptr<T>;
 
    // 构造函数
    constexpr shared_ptr() noexcept;
    constexpr shared_ptr(nullptr_t) noexcept
      : shared_ptr()
    {
    }
    template<class Y>
    explicit shared_ptr(Y* p);
    template<class Y, class D>
    shared_ptr(Y* p, D d);
    template<class Y, class D, class A>
    shared_ptr(Y* p, D d, A a);
    template<class D>
    shared_ptr(nullptr_t p, D d);
    template<class D, class A>
    shared_ptr(nullptr_t p, D d, A a);
    template<class Y>
    shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
    template<class Y>
    shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
    shared_ptr(const shared_ptr& r) noexcept;
    template<class Y>
    shared_ptr(const shared_ptr<Y>& r) noexcept;
    shared_ptr(shared_ptr&& r) noexcept;
    template<class Y>
    shared_ptr(shared_ptr<Y>&& r) noexcept;
    template<class Y>
    explicit shared_ptr(const weak_ptr<Y>& r);
    template<class Y, class D>
    shared_ptr(unique_ptr<Y, D>&& r);
 
    // 析构函数
    ~shared_ptr();
 
    // 赋值
    shared_ptr& operator=(const shared_ptr& r) noexcept;
    template<class Y>
    shared_ptr& operator=(const shared_ptr<Y>& r) noexcept;
    shared_ptr& operator=(shared_ptr&& r) noexcept;
    template<class Y>
    shared_ptr& operator=(shared_ptr<Y>&& r) noexcept;
    template<class Y, class D>
    shared_ptr& operator=(unique_ptr<Y, D>&& r);
 
    // 修改器
    void swap(shared_ptr& r) noexcept;
    void reset() noexcept;
    template<class Y>
    void reset(Y* p);
    template<class Y, class D>
    void reset(Y* p, D d);
    template<class Y, class D, class A>
    void reset(Y* p, D d, A a);
 
    // 观察器
    element_type* get() const noexcept;
    T& operator*() const noexcept;
    T* operator->() const noexcept;
    element_type& operator[](ptrdiff_t i) const;
    long use_count() const noexcept;
    explicit operator bool() const noexcept;
    template<class U>
    bool owner_before(const shared_ptr<U>& b) const noexcept;
    template<class U>
    bool owner_before(const weak_ptr<U>& b) const noexcept;
    size_t owner_hash() const noexcept;
    template<class U>
    bool owner_equal(const shared_ptr<U>& b) const noexcept;
    template<class U>
    bool owner_equal(const weak_ptr<U>& b) const noexcept;
  };
 
  template<class T>
  shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
  template<class T, class D>
  shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
}

类模板 std::weak_ptr

namespace std {
  template<class T>
  class weak_ptr
  {
  public:
    using element_type = remove_extent_t<T>;
 
    // 构造函数
    constexpr weak_ptr() noexcept;
    template<class Y>
    weak_ptr(const shared_ptr<Y>& r) noexcept;
    weak_ptr(const weak_ptr& r) noexcept;
    template<class Y>
    weak_ptr(const weak_ptr<Y>& r) noexcept;
    weak_ptr(weak_ptr&& r) noexcept;
    template<class Y>
    weak_ptr(weak_ptr<Y>&& r) noexcept;
 
    // 析构函数
    ~weak_ptr();
 
    // 赋值
    weak_ptr& operator=(const weak_ptr& r) noexcept;
    template<class Y>
    weak_ptr& operator=(const weak_ptr<Y>& r) noexcept;
    template<class Y>
    weak_ptr& operator=(const shared_ptr<Y>& r) noexcept;
    weak_ptr& operator=(weak_ptr&& r) noexcept;
    template<class Y>
    weak_ptr& operator=(weak_ptr<Y>&& r) noexcept;
 
    // 修改器
    void swap(weak_ptr& r) noexcept;
    void reset() noexcept;
 
    // 观察器
    long use_count() const noexcept;
    bool expired() const noexcept;
    shared_ptr<T> lock() const noexcept;
    template<class U>
    bool owner_before(const shared_ptr<U>& b) const noexcept;
    template<class U>
    bool owner_before(const weak_ptr<U>& b) const noexcept;
    size_t owner_hash() const noexcept;
    template<class U>
    bool owner_equal(const shared_ptr<U>& b) const noexcept;
    template<class U>
    bool owner_equal(const weak_ptr<U>& b) const noexcept;
  };
 
  template<class T>
  weak_ptr(shared_ptr<T>) -> weak_ptr<T>;
}

类模板 std::owner_less

namespace std {
  template<class T = void>
  struct owner_less;
 
  template<class T>
  struct owner_less<shared_ptr<T>>
  {
    bool operator()(const shared_ptr<T>&, const shared_ptr<T>&) const noexcept;
    bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
    bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
  };
 
  template<class T>
  struct owner_less<weak_ptr<T>>
  {
    bool operator()(const weak_ptr<T>&, const weak_ptr<T>&) const noexcept;
    bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
    bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
  };
 
  template<>
  struct owner_less<void>
  {
    template<class T, class U>
    bool operator()(const shared_ptr<T>&, const shared_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const shared_ptr<T>&, const weak_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const weak_ptr<T>&, const shared_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const weak_ptr<T>&, const weak_ptr<U>&) const noexcept;
 
    using is_transparent = /* 未指定 */;
  };
}

类 std::owner_hash

namespace std {
  struct owner_hash
  {
    template<class T>
    size_t operator()(const shared_ptr<T>&) const noexcept;
 
    template<class T>
    size_t operator()(const weak_ptr<T>&) const noexcept;
 
    using is_transparent = /* 未指定 */;
  };
}

类 std::owner_equal

namespace std {
  struct owner_equal
  {
    template<class T, class U>
    bool operator()(const shared_ptr<T>&, const shared_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const shared_ptr<T>&, const weak_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const weak_ptr<T>&, const shared_ptr<U>&) const noexcept;
    template<class T, class U>
    bool operator()(const weak_ptr<T>&, const weak_ptr<U>&) const noexcept;
 
    using is_transparent = /* 未指定 */;
  };
}

类模板 std::enable_shared_from_this

namespace std {
  template<class T>
  class enable_shared_from_this
  {
  protected:
    constexpr enable_shared_from_this() noexcept;
    enable_shared_from_this(const enable_shared_from_this&) noexcept;
    enable_shared_from_this& operator=(const enable_shared_from_this&) noexcept;
    ~enable_shared_from_this();
 
  public:
    shared_ptr<T> shared_from_this();
    shared_ptr<T const> shared_from_this() const;
    weak_ptr<T> weak_from_this() noexcept;
    weak_ptr<T const> weak_from_this() const noexcept;
 
  private:
    mutable weak_ptr<T> /*weak-this*/; // 仅用于阐述
  };
}

类模板 std::atomic's specialization for std::shared_ptr

namespace std {
  template<class T> struct atomic<shared_ptr<T>> {
    using value_type = shared_ptr<T>;
    static constexpr bool is_always_lock_free = /* 由实现定义 */;
 
    bool is_lock_free() const noexcept;
    void store(shared_ptr<T> desired, memory_order order = memory_order::seq_cst) noexcept;
    shared_ptr<T> load(memory_order order = memory_order::seq_cst) const noexcept;
    operator shared_ptr<T>() const noexcept;
 
    shared_ptr<T> exchange(shared_ptr<T> desired,
                           memory_order order = memory_order::seq_cst) noexcept;
 
    bool compare_exchange_weak(shared_ptr<T>& expected, shared_ptr<T> desired,
                               memory_order success, memory_order failure) noexcept;
    bool compare_exchange_strong(shared_ptr<T>& expected, shared_ptr<T> desired,
                                 memory_order success, memory_order failure) noexcept;
 
    bool compare_exchange_weak(shared_ptr<T>& expected, shared_ptr<T> desired,
                               memory_order order = memory_order::seq_cst) noexcept;
    bool compare_exchange_strong(shared_ptr<T>& expected, shared_ptr<T> desired,
                                 memory_order order = memory_order::seq_cst) noexcept;
 
    constexpr atomic() noexcept = default;
    atomic(shared_ptr<T> desired) noexcept;
    atomic(const atomic&) = delete;
    void operator=(const atomic&) = delete;
    void operator=(shared_ptr<T> desired) noexcept;
 
  private:
    shared_ptr<T> p;            // 仅用于阐述
  };
}

类模板 std::atomic's specialization for std::weak_ptr

namespace std {
  template<class T> struct atomic<weak_ptr<T>> {
    using value_type = weak_ptr<T>;
    static constexpr bool is_always_lock_free = /* 由实现定义 */;
 
    bool is_lock_free() const noexcept;
    void store(weak_ptr<T> desired, memory_order order = memory_order::seq_cst) noexcept;
    weak_ptr<T> load(memory_order order = memory_order::seq_cst) const noexcept;
    operator weak_ptr<T>() const noexcept;
 
    weak_ptr<T> exchange(weak_ptr<T> desired,
                         memory_order order = memory_order::seq_cst) noexcept;
 
    bool compare_exchange_weak(weak_ptr<T>& expected, weak_ptr<T> desired,
                               memory_order success, memory_order failure) noexcept;
    bool compare_exchange_strong(weak_ptr<T>& expected, weak_ptr<T> desired,
                                 memory_order success, memory_order failure) noexcept;
 
    bool compare_exchange_weak(weak_ptr<T>& expected, weak_ptr<T> desired,
                               memory_order order = memory_order::seq_cst) noexcept;
    bool compare_exchange_strong(weak_ptr<T>& expected, weak_ptr<T> desired,
                                 memory_order order = memory_order::seq_cst) noexcept;
 
    constexpr atomic() noexcept = default;
    atomic(weak_ptr<T> desired) noexcept;
    atomic(const atomic&) = delete;
    void operator=(const atomic&) = delete;
    void operator=(weak_ptr<T> desired) noexcept;
 
  private:
    weak_ptr<T> p;              // 仅用于阐述
  };
}

类模板 std::out_ptr_t

namespace std {
  template<class Smart, class Pointer, class... Args>
  class out_ptr_t
  {
  public:
    explicit out_ptr_t(Smart&, Args...);
    out_ptr_t(const out_ptr_t&) = delete;
 
    ~out_ptr_t();
 
    operator Pointer*() const noexcept;
    operator void**() const noexcept;
 
  private:
    Smart& s;         // 仅用于阐述
    tuple<Args...> a; // 仅用于阐述
    Pointer p;        // 仅用于阐述
  };
}

类模板 std::inout_ptr_t

namespace std {
  template<class Smart, class Pointer, class... Args>
  class inout_ptr_t
  {
  public:
    explicit inout_ptr_t(Smart&, Args...);
    inout_ptr_t(const inout_ptr_t&) = delete;
 
    ~inout_ptr_t();
 
    operator Pointer*() const noexcept;
    operator void**() const noexcept;
 
  private:
    Smart& s;         // 仅用于阐述
    tuple<Args...> a; // 仅用于阐述
    Pointer p;        // 仅用于阐述
  };
}

类模板 std::indirect

namespace std {
  template<class T, class Allocator = allocator<T>>
  class indirect
  {
  public:
    using value_type     = T;
    using allocator_type = Allocator;
    using pointer        = typename allocator_traits<Allocator>::pointer;
    using const_pointer  = typename allocator_traits<Allocator>::const_pointer;
 
    // 构造函数
    constexpr explicit indirect();
    constexpr explicit indirect(allocator_arg_t, const Allocator& a);
    constexpr indirect(const indirect& other);
    constexpr indirect(allocator_arg_t, const Allocator& a, const indirect& other);
    constexpr indirect(indirect&& other) noexcept;
    constexpr indirect(allocator_arg_t,
                       const Allocator& a,
                       indirect&& other) noexcept(/* 见描述 */);
    template<class U = T>
    constexpr explicit indirect(U&& u);
    template<class U = T>
    constexpr explicit indirect(allocator_arg_t, const Allocator& a, U&& u);
    template<class... Us>
    constexpr explicit indirect(in_place_t, Us&&... us);
    template<class... Us>
    constexpr explicit indirect(allocator_arg_t,
                                const Allocator& a,
                                in_place_t,
                                Us&&... us);
    template<class I, class... Us>
    constexpr explicit indirect(in_place_t, initializer_list<I> ilist, Us&&... us);
    template<class I, class... Us>
    constexpr explicit indirect(allocator_arg_t,
                                const Allocator& a,
                                in_place_t,
                                initializer_list<I> ilist,
                                Us&&... us);
 
    // 析构函数
    constexpr ~indirect();
 
    // 赋值
    constexpr indirect& operator=(const indirect& other);
    constexpr indirect& operator=(indirect&& other) noexcept(/* 见描述 */);
    template<class U = T>
    constexpr indirect& operator=(U&& u);
 
    // 观察器
    constexpr const T& operator*() const& noexcept;
    constexpr T& operator*() & noexcept;
    constexpr const T&& operator*() const&& noexcept;
    constexpr T&& operator*() && noexcept;
    constexpr const_pointer operator->() const noexcept;
    constexpr pointer operator->() noexcept;
    constexpr bool valueless_after_move() const noexcept;
    constexpr allocator_type get_allocator() const noexcept;
 
    // swap
    constexpr void swap(indirect& other) noexcept(/* 见描述 */);
    friend constexpr void swap(indirect& lhs,
                               indirect& rhs) noexcept(/* 见描述 */);
 
    // 关系运算符
    template<class U, class AA>
    friend constexpr bool operator==(
      const indirect& lhs,
      const indirect<U, AA>& rhs) noexcept(/* 见描述 */);
    template<class U, class AA>
    friend constexpr auto operator<=>(const indirect& lhs, const indirect<U, AA>& rhs)
      -> /*synth-three-way-result*/<T, U>;
 
    // 与 T 比较
    template<class U>
    friend constexpr bool operator==(const indirect& lhs,
                                     const U& rhs) noexcept(/* 见描述 */);
    template<class U>
    friend constexpr auto operator<=>(const indirect& lhs, const U& rhs)
      -> /*synth-three-way-result*/<T, U>;
 
  private:
    pointer /*p*/;                     // 仅用于阐述
    Allocator /*alloc*/ = Allocator(); // 仅用于阐述
  };
  template<class Value>
  indirect(Value) -> indirect<Value>;
  template<class Allocator, class Value>
  indirect(allocator_arg_t, Allocator, Value)
    -> indirect<Value,
                typename allocator_traits<Allocator>::template rebind_alloc<Value>>;
}

类模板 std::polymorphic

namespace std {
  template<class T, class Allocator = allocator<T>>
  class polymorphic
  {
  public:
    using value_type     = T;
    using allocator_type = Allocator;
    using pointer        = typename allocator_traits<Allocator>::pointer;
    using const_pointer  = typename allocator_traits<Allocator>::const_pointer;
 
    // 构造函数
    constexpr explicit polymorphic();
    constexpr explicit polymorphic(allocator_arg_t, const Allocator& a);
    constexpr polymorphic(const polymorphic& other);
    constexpr polymorphic(allocator_arg_t, const Allocator& a, const polymorphic& other);
    constexpr polymorphic(polymorphic&& other) noexcept;
    constexpr polymorphic(allocator_arg_t,
                          const Allocator& a,
                          polymorphic&& other) noexcept(/* 见描述 */);
    template<class U = T>
    constexpr explicit polymorphic(U&& u);
    template<class U = T>
    constexpr explicit polymorphic(allocator_arg_t, const Allocator& a, U&& u);
    template<class U, class... Ts>
    constexpr explicit polymorphic(in_place_type_t<U>, Ts&&... ts);
    template<class U, class... Ts>
    constexpr explicit polymorphic(allocator_arg_t,
                                   const Allocator& a,
                                   in_place_type_t<U>,
                                   Ts&&... ts);
    template<class U, class I, class... Us>
    constexpr explicit polymorphic(in_place_type_t<U>,
                                   initializer_list<I> ilist,
                                   Us&&... us);
    template<class U, class I, class... Us>
    constexpr explicit polymorphic(allocator_arg_t,
                                   const Allocator& a,
                                   in_place_type_t<U>,
                                   initializer_list<I> ilist,
                                   Us&&... us);
 
    // 析构函数
    constexpr ~polymorphic();
 
    // 赋值
    constexpr polymorphic& operator=(const polymorphic& other);
    constexpr polymorphic& operator=(polymorphic&& other) noexcept(/* 见描述 */);
 
    // 观察器
    constexpr const T& operator*() const noexcept;
    constexpr T& operator*() noexcept;
    constexpr const_pointer operator->() const noexcept;
    constexpr pointer operator->() noexcept;
    constexpr bool valueless_after_move() const noexcept;
    constexpr allocator_type get_allocator() const noexcept;
 
    // swap
    constexpr void swap(polymorphic& other) noexcept(/* 见描述 */);
    friend constexpr void swap(polymorphic& lhs,
                               polymorphic& rhs) noexcept(/* 见描述 */);
 
  private:
    Allocator /*alloc*/ = Allocator(); // 仅用于阐述
  };
}
来自“https://zh.cppreference.com/mwiki/index.php?title=cpp/header/memory&oldid=100467”