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標準庫標頭檔案 <functional>

來自 cppreference.com
 
C++
 
標準庫標頭檔案
通用工具
<any> (C++17)
<bitset>
<bit> (C++20)
<charconv> (C++17)
<expected> (C++23)
<format> (C++20)
<functional>
<optional> (C++17)
<tuple> (C++11)
<typeindex> (C++11)
<utility>
<variant> (C++17)
容器
<array> (C++11)
<deque>
<flat_map> (C++23)
<flat_set> (C++23)
<forward_list> (C++11)
<hive> (C++26)
<inplace_vector> (C++26)   
<list>
<map>
<mdspan> (C++23)
<queue>
<set>
<span> (C++20)
<stack>
<unordered_map> (C++11)
<unordered_set> (C++11)
<vector>
迭代器
<iterator>
Ranges
<generator> (C++23)
<ranges> (C++20)
演算法
<algorithm>
<numeric>
字串
<cctype>
<cstring>
<cuchar> (C++11)
<cwchar>
<cwctype>
<string_view> (C++17)
<string>
文字處理
<clocale>
<codecvt> (C++11/17/26*)
<locale>
<regex> (C++11)
<text_encoding> (C++26)   
數值
<cfenv> (C++11)
<cmath>
<complex>
<linalg> (C++26)
<numbers> (C++20)
<random> (C++11)
<simd> (C++26)
<valarray>
時間
<chrono> (C++11)
<ctime>
C 相容性
<ccomplex> (C++11/17/20*)
<ciso646> (until C++20)
<cstdalign> (C++11/17/20*)
<cstdbool> (C++11/17/20*)
<ctgmath> (C++11/17/20*)
 

此標頭檔案是函式物件庫的一部分，並提供標準雜湊函式。

目錄

名稱空間

placeholders (C++11) 為 std::bind 表示式中的未繫結引數提供佔位符

類

包裝器
(C++11)
 任何可複製構造的可呼叫物件的包裝器
(類模板) [編輯]
(C++23)
 任何支援給定呼叫簽名中限定符的可呼叫物件的僅移動包裝器
(類模板) [編輯]
(C++26)
 任何可複製構造的可呼叫物件的包裝器，支援給定呼叫簽名中的限定符
(類模板) [編輯]
(C++26)
 任何可呼叫物件的非擁有包裝器
(類模板) [編輯]
(C++11)
 從指向成員的指標建立函式物件
(函式模板) [編輯]
(C++11)
 CopyConstructible 和 CopyAssignable 引用包裝器
(類模板) [編輯]
(C++20)(C++20)
 獲取包裝在 std::reference_wrapper 中的引用型別
(類模板) [編輯]
輔助類
(C++11)
 呼叫空的 std::function 時丟擲的異常
(類) [編輯]
(C++11)
 指示一個物件是 `std::bind` 表示式或可用作 `std::bind` 表示式
(類模板) [編輯]
(C++11)
 指示一個物件是標準佔位符或可用作標準佔位符
(類模板) [編輯]
算術運算
 實現 x + y 的函式物件
(類模板) [編輯]
 實現 x - y 的函式物件
(類模板) [編輯]
 實現 x * y 的函式物件
(類模板) [編輯]
 實現 x / y 的函式物件
(類模板) [編輯]
 實現 x % y 的函式物件
(類模板) [編輯]
 實現 -x 的函式物件
(類模板) [編輯]
比較
 實現 x == y 的函式物件
(類模板) [編輯]
 實現 x != y 的函式物件
(類模板) [編輯]
 實現 x > y 的函式物件
(類模板) [編輯]
 實現 x < y 的函式物件
(類模板) [編輯]
 實現 x >= y 的函式物件
(類模板) [編輯]
 實現 x <= y 的函式物件
(類模板) [編輯]
概念約束比較
(C++20)
 實現 x == y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x != y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x > y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x < y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x >= y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x <= y 的受限函式物件
(類) [編輯]
(C++20)
 實現 x <=> y 的受限函式物件
(類) [編輯]
邏輯運算
 實現 x && y 的函式物件
(類模板) [編輯]
 實現 x || y 的函式物件
(類模板) [編輯]
 實現 !x 的函式物件
(類模板) [編輯]
位運算
 實現 x & y 的函式物件
(類模板) [編輯]
 實現 x | y 的函式物件
(類模板) [編輯]
 實現 x ^ y 的函式物件
(類模板) [編輯]
(C++14)
 實現 ~x 的函式物件
(類模板) [編輯]
否定器
(C++17)
 建立函式物件，該物件返回其所持函式物件結果的補數
(函式模板) [編輯]
恆等式
(C++20)
 返回其引數不變的函式物件
(類) [編輯]
搜尋器
(C++17)
 標準 C++ 庫搜尋演算法實現
(類模板) [編輯]
(C++17)
 Boyer-Moore 搜尋演算法實現
(類模板) [編輯]
(C++17)
 Boyer-Moore-Horspool 搜尋演算法實現
(類模板) [編輯]
雜湊
(C++11)
 雜湊函式物件
(類模板) [編輯]
(C++11)
 std::hash 對基本型別、列舉型別和指標型別的特化
(類模板特化)

常量

在名稱空間 std::placeholders 中定義
(C++11)
 std::bind 表示式中未繫結引數的佔位符
(常數) [編輯]

函式

(C++20)(C++23)
 按順序將可變數量的引數繫結到函式物件
(函式模板) [編輯]
(C++11)
 將一個或多個引數繫結到函式物件
(函式模板) [編輯]
(C++11)(C++11)
 根據其引數推導型別建立 std::reference_wrapper
(函式模板) [編輯]
(C++17)(C++23)
 使用給定引數呼叫任何 可呼叫 物件 並可指定返回型別(C++23 起)
(函式模板) [編輯]

[編輯] C++11中棄用，C++17中移除

基類
(C++11 中已廢棄)(C++17 中已移除)
 與介面卡相容的一元函式基類
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 與介面卡相容的二元函式基類
(類模板) [編輯]
繫結器
(C++11 中已廢棄)(C++17 中已移除)
 儲存二元函式及其一個引數的函式物件
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 將一個引數繫結到二元函式
(函式模板) [編輯]
函式介面卡
(C++11 中已廢棄)(C++17 中已移除)
 指向一元函式的指標的介面卡相容包裝器
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 指向二元函式的指標的介面卡相容包裝器
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 從函式指標建立介面卡相容函式物件包裝器
(函式模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 指向無參或一元成員函式的指標的包裝器，可使用物件指標呼叫
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 從成員函式指標建立包裝器，可使用物件指標呼叫
(函式模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 指向無參或一元成員函式的指標的包裝器，可使用物件引用呼叫
(類模板) [編輯]
(C++11 中已廢棄)(C++17 中已移除)
 從成員函式指標建立包裝器，可使用物件引用呼叫
(函式模板) [編輯]

[編輯] C++17中棄用，C++20中移除

否定器
(C++17 中已棄用)(C++20 中已移除)
 返回其所持一元謂詞補集的包裝函式物件
(類模板) [編輯]
(C++17 中已棄用)(C++20 中已移除)
 返回其所持二元謂詞補集的包裝函式物件
(類模板) [編輯]
(C++17 中已棄用)(C++20 中已移除)
 構造自定義的 std::unary_negate 物件
(函式模板) [編輯]
(C++17 中已棄用)(C++20 中已移除)
 構造自定義的 std::binary_negate 物件
(函式模板) [編輯]

[編輯] 概要

namespace std {
  // invoke
  template<class F, class... Args>
    constexpr invoke_result_t<F, Args...> invoke(F&& f, Args&&... args)
      noexcept(is_nothrow_invocable_v<F, Args...>);
  template<class R, class F, class... Args>
    constexpr R invoke_r(F&& f, Args&&... args)
      noexcept(is_nothrow_invocable_r_v<R, F, Args...>);
 
  // reference_wrapper
  template<class T> class reference_wrapper;
 
  template<class T> constexpr reference_wrapper<T> ref(T&) noexcept;
  template<class T> constexpr reference_wrapper<const T> cref(const T&) noexcept;
  template<class T> void ref(const T&&) = delete;
  template<class T> void cref(const T&&) = delete;
 
  template<class T>
    constexpr reference_wrapper<T> ref(reference_wrapper<T>) noexcept;
  template<class T>
    constexpr reference_wrapper<const T> cref(reference_wrapper<T>) noexcept;
 
  template<class T> struct unwrap_reference;
  template<class T> using unwrap_reference_t = typename unwrap_reference<T>::type;
  template<class T> struct unwrap_ref_decay;
  template<class T> using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type;
 
  // common_reference related specializations
  template<class R, class T, template<class> class RQual, template<class> class TQual>
    requires /* see below */
  struct basic_common_reference<R, T, RQual, TQual>;
 
  template<class T, class R, template<class> class TQual, template<class> class RQual>
    requires /* see below */
  struct basic_common_reference<T, R, TQual, RQual>;
 
  // arithmetic operations
  template<class T = void> struct plus;
  template<class T = void> struct minus;
  template<class T = void> struct multiplies;
  template<class T = void> struct divides;
  template<class T = void> struct modulus;
  template<class T = void> struct negate;
  template<> struct plus<void>;
  template<> struct minus<void>;
  template<> struct multiplies<void>;
  template<> struct divides<void>;
  template<> struct modulus<void>;
  template<> struct negate<void>;
 
  // comparisons
  template<class T = void> struct equal_to;
  template<class T = void> struct not_equal_to;
  template<class T = void> struct greater;
  template<class T = void> struct less;
  template<class T = void> struct greater_equal;
  template<class T = void> struct less_equal;
  template<> struct equal_to<void>;
  template<> struct not_equal_to<void>;
  template<> struct greater<void>;
  template<> struct less<void>;
  template<> struct greater_equal<void>;
  template<> struct less_equal<void>;
 
  // logical operations
  template<class T = void> struct logical_and;
  template<class T = void> struct logical_or;
  template<class T = void> struct logical_not;
  template<> struct logical_and<void>;
  template<> struct logical_or<void>;
  template<> struct logical_not<void>;
 
  // bitwise operations
  template<class T = void> struct bit_and;
  template<class T = void> struct bit_or;
  template<class T = void> struct bit_xor;
  template<class T = void> struct bit_not;
  template<> struct bit_and<void>;
  template<> struct bit_or<void>;
  template<> struct bit_xor<void>;
  template<> struct bit_not<void>;
 
  // identity
  struct identity;
 
  // function template not_fn
  template<class F> constexpr /* unspecified */ not_fn(F&& f);
 
  // function templates bind_front and bind_back
  template<class F, class... Args> constexpr /* unspecified */ bind_front(F&&, Args&&...);
  template<class F, class... Args> constexpr /* unspecified */ bind_back(F&&, Args&&...);
 
  // bind
  template<class T> struct is_bind_expression;
  template<class T>
    inline constexpr bool is_bind_expression_v = is_bind_expression<T>::value;
 
  template<class T> struct is_placeholder;
  template<class T>
    inline constexpr int is_placeholder_v = is_placeholder<T>::value;
 
  template<class F, class... BoundArgs>
    constexpr /* unspecified */ bind(F&&, BoundArgs&&...);
  template<class R, class F, class... BoundArgs>
    constexpr /* unspecified */ bind(F&&, BoundArgs&&...);
 
  namespace placeholders {
    // M is the implementation-defined number of placeholders
    /* see description */ _1;
    /* see description */ _2;
               .
               .
               .
    /* see description */ _M;
  }
 
  // member function adaptors
  template<class R, class T>
    constexpr /* unspecified */ mem_fn(R T::*) noexcept;
 
  // polymorphic function wrappers
  class bad_function_call;
 
  template<class> class function; // not defined
  template<class R, class... ArgTypes> class function<R(ArgTypes...)>;
 
  template<class R, class... ArgTypes>
    void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;
 
  template<class R, class... ArgTypes>
    bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
 
  // move-only wrapper
  template<class...> class move_only_function; // not defined
 
  template<class R, class... ArgTypes>
    class move_only_function<R(ArgTypes...) /*cv ref*/ noexcept(/*noex*/)>;
 
  // copyable wrapper
  template<class...> class copyable_function; // not defined
 
  template<class R, class... ArgTypes>
    class copyable_function<R(ArgTypes...) /*cv ref*/ noexcept(/*noex*/)>;
 
  // non-owning wrapper
  template<class...> class function_ref; // not defined
 
  template<class R, class... ArgTypes>
    class function_ref<R(ArgTypes...) /*cv*/ noexcept(/*noex*/)>;
 
  // searchers
  template<class ForwardIter, class BinaryPredicate = equal_to<>>
    class default_searcher;
 
  template<class RandomAccessIter,
           class Hash = hash<typename iterator_traits<RandomAccessIter>::value_type>,
           class BinaryPredicate = equal_to<>>
    class boyer_moore_searcher;
 
  template<class RandomAccessIter,
           class Hash = hash<typename iterator_traits<RandomAccessIter>::value_type>,
           class BinaryPredicate = equal_to<>>
    class boyer_moore_horspool_searcher;
 
  // hash function primary template
  template<class T>
    struct hash;
 
  // concept-constrained comparisons
  struct compare_three_way;
  namespace ranges {
    struct equal_to;
    struct not_equal_to;
    struct greater;
    struct less;
    struct greater_equal;
    struct less_equal;
  }
 
  // exposition only
  template<class Fn, class... Args>
    concept /*callable*/ =
      requires (Fn&& fn, Args&&... args) {
        std::forward<Fn>(fn)(std::forward<Args>(args)...);
      };
 
  // exposition only
  template<class Fn, class... Args>
    concept /*nothrow-callable*/ =
      /*callable*/<Fn, Args...> &&
      requires (Fn&& fn, Args&&... args) {
        { std::forward<Fn>(fn)(std::forward<Args>(args)...) } noexcept;
      };
 
  // exposition only
  template<class Fn, class... Args>
    using /*call-result-t*/ = decltype(std::declval<Fn>()(std::declval<Args>()...));
 
  // exposition only
  template<const auto& T>
    using /*decayed-typeof*/ = decltype(auto(T));
}

[編輯] 類模板 std::reference_wrapper

namespace std {
  template<class T> class reference_wrapper {
  public:
    // types
    using type = T;
 
    // construct/copy/destroy
    template<class U>
      constexpr reference_wrapper(U&&) noexcept(/* see below */);
    constexpr reference_wrapper(const reference_wrapper& x) noexcept;
 
    // assignment
    constexpr reference_wrapper& operator=(const reference_wrapper& x) noexcept;
 
    // access
    constexpr operator T& () const noexcept;
    constexpr T& get() const noexcept;
 
    // invocation
    template<class... ArgTypes>
      constexpr invoke_result_t<T&, ArgTypes...> operator()(ArgTypes&&...) const
        noexcept(is_nothrow_invocable_v<T&, ArgTypes...>);
 
    // comparison
    friend constexpr bool operator==(reference_wrapper, reference_wrapper);
    friend constexpr bool operator==(reference_wrapper, const T&);
    friend constexpr bool operator==(reference_wrapper, reference_wrapper<const T>);
 
    friend constexpr auto operator<=>(reference_wrapper, reference_wrapper);
    friend constexpr auto operator<=>(reference_wrapper, const T&);
    friend constexpr auto operator<=>(reference_wrapper, reference_wrapper<const T>);
  };
  // deduction guides
  template<class T>
    reference_wrapper(T&) -> reference_wrapper<T>;
}

[編輯] 類模板 std::unwrap_reference

namespace std {
  template<class T>
    struct unwrap_reference;
}

[編輯] 類模板 std::unwrap_ref_decay

namespace std {
  template<class T>
    struct unwrap_ref_decay;
}

[編輯] 類模板 std::plus

namespace std {
  template<class T = void> struct plus {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct plus<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) + std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::minus

namespace std {
  template<class T = void> struct minus {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct minus<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) - std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::multiplies

namespace std {
  template<class T = void> struct multiplies {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct multiplies<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) * std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::divides

namespace std {
  template<class T = void> struct divides {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct divides<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) / std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::modulus

namespace std {
  template<class T = void> struct modulus {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct modulus<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) % std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::negate

namespace std {
  template<class T = void> struct negate {
    constexpr T operator()(const T& x) const;
  };
 
  template<> struct negate<void> {
    template<class T> constexpr auto operator()(T&& t) const
      -> decltype(-std::forward<T>(t));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::equal_to

namespace std {
  template<class T = void> struct equal_to {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct equal_to<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) == std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::not_equal_to

namespace std {
  template<class T = void> struct not_equal_to {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct not_equal_to<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) != std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::greater

namespace std {
  template<class T = void> struct greater {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct greater<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) > std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::less

namespace std {
  template<class T = void> struct less {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct less<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) < std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::greater_equal

namespace std {
  template<class T = void> struct greater_equal {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct greater_equal<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) >= std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::less_equal

namespace std {
  template<class T = void> struct less_equal {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct less_equal<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) <= std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::compare_three_way

namespace std {
  struct compare_three_way {
    template<class T, class U>
    constexpr auto operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::equal_to

namespace std::ranges {
  struct equal_to {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::not_equal_to

namespace std::ranges {
  struct not_equal_to {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::greater

namespace std::ranges {
  struct greater {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::less

namespace std::ranges {
  struct less {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::greater_equal

namespace std::ranges {
  struct greater_equal {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類 std::ranges::less_equal

namespace std::ranges {
  struct less_equal {
    template<class T, class U>
    constexpr bool operator()(T&& t, U&& u) const;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::logical_and

namespace std {
  template<class T = void> struct logical_and {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct logical_and<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) && std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::logical_or

namespace std {
  template<class T = void> struct logical_or {
    constexpr bool operator()(const T& x, const T& y) const;
  };
 
  template<> struct logical_or<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) || std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::logical_not

namespace std {
  template<class T = void> struct logical_not {
    constexpr bool operator()(const T& x) const;
  };
 
  template<> struct logical_not<void> {
    template<class T> constexpr auto operator()(T&& t) const
      -> decltype(!std::forward<T>(t));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::bit_and

namespace std {
  template<class T = void> struct bit_and {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct bit_and<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) & std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::bit_or

namespace std {
  template<class T = void> struct bit_or {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct bit_or<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) | std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::bit_xor

namespace std {
  template<class T = void> struct bit_xor {
    constexpr T operator()(const T& x, const T& y) const;
  };
 
  template<> struct bit_xor<void> {
    template<class T, class U> constexpr auto operator()(T&& t, U&& u) const
      -> decltype(std::forward<T>(t) ^ std::forward<U>(u));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::bit_not

namespace std {
  template<class T = void> struct bit_not {
    constexpr T operator()(const T& x) const;
  };
 
  template<> struct bit_not<void> {
    template<class T> constexpr auto operator()(T&& t) const
      -> decltype(~std::forward<T>(t));
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::identity

namespace std {
  struct identity {
    template<class T>
      constexpr T&& operator()(T&& t) const noexcept;
 
    using is_transparent = /* unspecified */;
  };
}

[編輯] 類模板 std::is_bind_expression

namespace std {
  template<class T> struct is_bind_expression;
}

[編輯] 類模板 std::is_placeholder

namespace std {
  template<class T> struct is_placeholder;
}

[編輯] 類 std::bad_function_call

namespace std {
  class bad_function_call : public exception {
  public:
    // see [exception] for the specification of the special member functions
    const char* what() const noexcept override;
  };
}

[編輯] 類模板 std::function

namespace std {
  template<class> class function; // not defined
 
  template<class R, class... ArgTypes>
  class function<R(ArgTypes...)> {
  public:
    using result_type = R;
 
    // construct/copy/destroy
    function() noexcept;
    function(nullptr_t) noexcept;
    function(const function&);
    function(function&&) noexcept;
    template<class F> function(F);
 
    function& operator=(const function&);
    function& operator=(function&&);
    function& operator=(nullptr_t) noexcept;
    template<class F> function& operator=(F&&);
    template<class F> function& operator=(reference_wrapper<F>) noexcept;
 
    ~function();
 
    // function modifiers
    void swap(function&) noexcept;
 
    // function capacity
    explicit operator bool() const noexcept;
 
    // function invocation
    R operator()(ArgTypes...) const;
 
    // function target access
    const type_info& target_type() const noexcept;
    template<class T>       T* target() noexcept;
    template<class T> const T* target() const noexcept;
  };
 
  template<class R, class... ArgTypes>
    function(R(*)(ArgTypes...)) -> function<R(ArgTypes...)>;
 
  template<class F> function(F) -> function</* see description */>;
 
  // null pointer comparison functions
  template<class R, class... ArgTypes>
    bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
 
  // specialized algorithms
  template<class R, class... ArgTypes>
    void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;
}

[編輯] 類模板 std::move_only_function

namespace std {
  template<class... S> class move_only_function; // not defined
 
  template<class R, class... ArgTypes>
  class move_only_function<R(ArgTypes...) /*cv-ref*/ noexcept(/*noex*/)> {
  public:
    using result_type = R;
 
    // construct/move/destroy
    move_only_function() noexcept;
    move_only_function(nullptr_t) noexcept;
    move_only_function(move_only_function&&) noexcept;
    template<class F> move_only_function(F&&);
 
    template<class T, class... Args>
      explicit move_only_function(in_place_type_t<T>, Args&&...);
    template<class T, class U, class... Args>
      explicit move_only_function(in_place_type_t<T>, initializer_list<U>, Args&&...);
 
    move_only_function& operator=(move_only_function&&);
    move_only_function& operator=(nullptr_t) noexcept;
    template<class F> move_only_function& operator=(F&&);
 
    ~move_only_function();
 
    // invocation
    explicit operator bool() const noexcept;
 
    R operator()(ArgTypes...) /*cv-ref*/ noexcept(/*noex*/);
 
    // utility
    void swap(move_only_function&) noexcept;
 
    friend void swap(move_only_function&, move_only_function&) noexcept;
 
    friend bool operator==(const move_only_function&, nullptr_t) noexcept;
 
  private:
    // exposition-only
    template<class VT>
      static constexpr bool /*is-callable-from*/ = /* see description */; 
  };
}

[編輯] 類模板 std::copyable_function

namespace std {
  template<class... S> class copyable_function; // not defined
 
  template<class R, class... ArgTypes>
  class copyable_function<R(ArgTypes...) /*cv-ref*/ noexcept(/*noex*/)> {
  public:
    using result_type = R;
 
    // construct/move/destroy
    copyable_function() noexcept;
    copyable_function(nullptr_t) noexcept;
    copyable_function(const copyable_function&);
    copyable_function(copyable_function&&) noexcept;
    template<class F> copyable_function(F&&);
 
    template<class T, class... Args>
      explicit copyable_function(in_place_type_t<T>, Args&&...);
    template<class T, class U, class... Args>
      explicit copyable_function(in_place_type_t<T>, initializer_list<U>, Args&&...);
 
    copyable_function& operator=(const copyable_function&);
    copyable_function& operator=(copyable_function&&);
    copyable_function& operator=(nullptr_t) noexcept;
    template<class F> copyable_function& operator=(F&&);
 
    ~copyable_function();
 
    // invocation
    explicit operator bool() const noexcept;
 
    R operator()(ArgTypes...) /*cv-ref*/ noexcept(/*noex*/);
 
    // utility
    void swap(copyable_function&) noexcept;
 
    friend void swap(copyable_function&, copyable_function&) noexcept;
 
    friend bool operator==(const copyable_function&, nullptr_t) noexcept;
 
  private:
    // exposition-only
    template<class VT>
      static constexpr bool /*is-callable-from*/ = /* see description */; 
  };
}

[編輯] 類模板 std::function_ref

namespace std {
  template<class... S> class function_ref; // not defined
 
  template<class R, class... ArgTypes>
  class function_ref<R(ArgTypes...) /*cv*/ noexcept(/*noex*/)> {
  public:
    // constructors and assignment operators
    template<class F> function_ref(F*) noexcept;
    template<class F> constexpr function_ref(F&&) noexcept;
    template<auto f> constexpr function_ref(nontype_t<f>) noexcept;
    template<auto f, class U>
      constexpr function_ref(nontype_t<f>, U&&) noexcept;
    template<auto f, class T>
      constexpr function_ref(nontype_t<f>, /*cv*/ T*) noexcept;
 
    constexpr function_ref(const function_ref&) noexcept = default;
    constexpr function_ref& operator=(const function_ref&) noexcept = default;
    template<class T> function_ref& operator=(T) = delete;
 
    // invocation
    R operator()(ArgTypes...) /*cv*/ noexcept(/*noex*/);
 
  private:
    // exposition-only
    template<class... T>
      static constexpr bool /*is-invocable-using*/ = /* see description */;
 
    R (*thunk-ptr)(BoundEntityType, ArgTypes&&...) noexcept(/*noex*/); // exposition-only
    BoundEntityType bound-entity; // exposition-only
  };
  // deduction guides
  template<class F>
    function_ref(F*) -> function_ref<F>;
  template<auto f>
    function_ref(nontype_t<f>) -> function_ref</* see description */>;
  template<auto f, class T>
    function_ref(nontype_t<f>, T&&) -> function_ref</* see description */>;
}

[編輯] 類模板 std::default_searcher

namespace std {
  template<class ForwardIter1, class BinaryPredicate = equal_to<>>
    class default_searcher {
    public:
      constexpr default_searcher(ForwardIter1 pat_first, ForwardIter1 pat_last,
                                 BinaryPredicate pred = BinaryPredicate());
 
      template<class ForwardIter2>
        constexpr pair<ForwardIter2, ForwardIter2>
          operator()(ForwardIter2 first, ForwardIter2 last) const;
 
    private:
      ForwardIter1 pat_first_;            // exposition only
      ForwardIter1 pat_last_;             // exposition only
      BinaryPredicate pred_;              // exposition only
  };
}

[編輯] 類模板 std::boyer_moore_searcher

namespace std {
  template<class RandomAccessIter1,
           class Hash = hash<typename iterator_traits<RandomAccessIter1>::value_type>,
           class BinaryPredicate = equal_to<>>
    class boyer_moore_searcher {
    public:
      boyer_moore_searcher(RandomAccessIter1 pat_first,
                           RandomAccessIter1 pat_last,
                           Hash hf = Hash(),
                           BinaryPredicate pred = BinaryPredicate());
 
      template<class RandomAccessIter2>
        pair<RandomAccessIter2, RandomAccessIter2>
          operator()(RandomAccessIter2 first, RandomAccessIter2 last) const;
 
    private:
      RandomAccessIter1 pat_first_;       // exposition only
      RandomAccessIter1 pat_last_;        // exposition only
      Hash hash_;                         // exposition only
      BinaryPredicate pred_;              // exposition only
    };
}

[編輯] 類模板 std::boyer_moore_horspool_searcher

namespace std {
  template<class RandomAccessIter1,
           class Hash = hash<typename iterator_traits<RandomAccessIter1>::value_type>,
           class BinaryPredicate = equal_to<>>
    class boyer_moore_horspool_searcher {
    public:
      boyer_moore_horspool_searcher(RandomAccessIter1 pat_first,
                                    RandomAccessIter1 pat_last,
                                    Hash hf = Hash(),
                                    BinaryPredicate pred = BinaryPredicate());
 
      template<class RandomAccessIter2>
        pair<RandomAccessIter2, RandomAccessIter2>
          operator()(RandomAccessIter2 first, RandomAccessIter2 last) const;
 
    private:
      RandomAccessIter1 pat_first_;       // exposition only
      RandomAccessIter1 pat_last_;        // exposition only
      Hash hash_;                         // exposition only
      BinaryPredicate pred_;              // exposition only
  };
}

[編輯] 參閱

std::hash 庫型別的特化
取自 “https://cppreference.tw/mwiki/index.php?title=cpp/header/functional&oldid=173900”