# 标准库头文件 <stacktrace>

< cpp‎ | header

此头文件是通用工具库的一部分。

### 类
stacktrace_entry (C++23) | 栈踪中求值的表示 (类)
basic_stacktrace (C++23) | 由栈踪条目组成的调用序列的近似表示 (类模板)
std::hash<std::stacktrace_entry> (C++23) | std::stacktrace_entry 的散列支持 (类模板特化)
std::hash<std::basic_stacktrace> (C++23) | std::basic_stacktrace 的散列支持 (类模板特化)
##### 前置声明
定义于头文件 `<functional>`
hash (C++11) | 散列函数对象 (类模板)
### 函数
std::swap(std::basic_stacktrace) (C++23) | 特化 std::swap 算法 (函数模板)
to_string (C++23) | 返回拥有 `stacktrace_entry` 的描述的字符串 (函数)
to_string (C++23) | 返回拥有 `basic_stacktrace` 的描述的字符串 (函数模板)
operator<< (C++23) | 进行 `stacktrace_entry` 的流输出 (函数模板)
operator<< (C++23) | 进行 `basic_stracktrace` 的流输出 (函数模板)

### 概要

    namespace std {
      // 类 stacktrace_entry
      class stacktrace_entry;

      // 类模板 basic_stacktrace
      template<class Allocator>
        class basic_stacktrace;

      // basic_stacktrace typedef 名
      using stacktrace = basic_stacktrace<allocator<stacktrace_entry>>;

      // 非成员函数
      template<class Allocator>
        void swap(basic_stacktrace<Allocator>& a, basic_stacktrace<Allocator>& b)
          noexcept(noexcept(a.swap(b)));

      string to_string(const stacktrace_entry& f);

      template<class Allocator>
        string to_string(const basic_stacktrace<Allocator>& st);

      template<class CharT, class traits>
        basic_ostream<CharT, traits>&
          operator<<(basic_ostream<CharT, traits>& os, const stacktrace_entry& f);

      template<class CharT, class Traits, class Allocator>
        basic_ostream<CharT, traits>&
          operator<<(basic_ostream<CharT, Traits>& os, const basic_stacktrace<Allocator>& st);

      namespace pmr {
        using stacktrace = std::basic_stacktrace<polymorphic_allocator<stacktrace_entry>>;
      }

      // 散列支持
      template<class T> struct hash;
      template<> struct hash<stacktrace_entry>;
      template<class Allocator> struct hash<basic_stacktrace<Allocator>>;
    }

#### 类 std::stacktrace_entry

    namespace std {
      class stacktrace_entry {
      public:
        using native_handle_type = /* 由实现定义 */;

        // 构造函数
        constexpr stacktrace_entry() noexcept;
        constexpr stacktrace_entry(const stacktrace_entry& other) noexcept;
        constexpr stacktrace_entry& operator=(const stacktrace_entry& other) noexcept;

        ~stacktrace_entry();

        // 观察器
        constexpr native_handle_type native_handle() const noexcept;
        constexpr explicit operator bool() const noexcept;

        // 查询
        string description() const;
        string source_file() const;
        uint_least32_t source_line() const;

        // 比较
        friend constexpr bool operator==(const stacktrace_entry& x,
                                         const stacktrace_entry& y) noexcept;
        friend constexpr strong_ordering operator<=>(const stacktrace_entry& x,
                                                     const stacktrace_entry& y) noexcept;
      };
    }

#### 类模板 std::basic_stacktrace

    namespace std {
      template<class Allocator>
      class basic_stacktrace {
      public:
        using value_type = stacktrace_entry;
        using const_reference = const value_type&;
        using reference = value_type&;
        using const_iterator = /* 由实现定义 */;
        using iterator = const_iterator;
        using reverse_iterator = std::reverse_iterator<iterator>;
        using const_reverse_iterator = std::reverse_iterator<const_iterator>;
        using difference_type = /* 由实现定义 */;
        using size_type = /* 由实现定义 */;
        using allocator_type = Allocator;

        // 创建与赋值
        static basic_stacktrace
          current(const allocator_type& alloc = allocator_type()) noexcept;
        static basic_stacktrace
          current(size_type skip, const allocator_type& alloc = allocator_type()) noexcept;
        static basic_stacktrace
          current(size_type skip, size_type max_depth,
                  const allocator_type& alloc = allocator_type()) noexcept;

        basic_stacktrace() noexcept(is_nothrow_default_constructible_v<allocator_type>);
        explicit basic_stacktrace(const allocator_type& alloc) noexcept;

        basic_stacktrace(const basic_stacktrace& other);
        basic_stacktrace(basic_stacktrace&& other) noexcept;
        basic_stacktrace(const basic_stacktrace& other, const allocator_type& alloc);
        basic_stacktrace(basic_stacktrace&& other, const allocator_type& alloc);
        basic_stacktrace& operator=(const basic_stacktrace& other);
        basic_stacktrace& operator=(basic_stacktrace&& other) noexcept(
            allocator_traits<Allocator>::propagate_on_container_move_assignment::value ||
            allocator_traits<Allocator>::is_always_equal::value);

        ~basic_stacktrace();

        // 观察器
        allocator_type get_allocator() const noexcept;

        const_iterator begin() const noexcept;
        const_iterator end() const noexcept;
        const_reverse_iterator rbegin() const noexcept;
        const_reverse_iterator rend() const noexcept;

        const_iterator cbegin() const noexcept;
        const_iterator cend() const noexcept;
        const_reverse_iterator crbegin() const noexcept;
        const_reverse_iterator crend() const noexcept;

        [[nodiscard]] bool empty() const noexcept;
        size_type size() const noexcept;
        size_type max_size() const noexcept;

        const_reference operator[](size_type) const;
        const_reference at(size_type) const;

        // 比较
        template<class Allocator2>
        friend bool operator==(const basic_stacktrace& x,
                               const basic_stacktrace<Allocator2>& y) noexcept;
        template<class Allocator2>
        friend strong_ordering operator<=>(const basic_stacktrace& x,
                                           const basic_stacktrace<Allocator2>& y) noexcept;

        // 修改器
        void swap(basic_stacktrace& other)
          noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
            allocator_traits<Allocator>::is_always_equal::value);

      private:
        vector<value_type, allocator_type> frames_;         // 仅用于阐释
      };
    }