Namespaces
Variants
Actions

Standard library header <utility>

From cppreference.com
< cpp‎ | header
 
 
Standard library headers
General utilities
<any> (C++17)
<bitset>
<bit> (C++20)
<charconv> (C++17)
<expected> (C++23)
<format> (C++20)
<functional>
<optional> (C++17)
<stdbit.h> (C++26)
<tuple> (C++11)
<typeindex> (C++11)
<utility>
<variant> (C++17)
Containers
<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>
Iterators
<iterator>
Ranges
<generator> (C++23)
<ranges> (C++20)
 

This header is part of the general utility library.

Contents

Includes

(C++20)
Three-way comparison operator support[edit]
std::initializer_list class template[edit]

Namespaces

rel_ops Provide automatic comparison operators
Defined in namespace std::rel_ops
automatically generates comparison operators based on user-defined operator== and operator<
(function template) [edit]

Functions

swaps the values of two objects
(function template) [edit]
(C++14)
replaces the argument with a new value and returns its previous value
(function template) [edit]
(C++11)
forwards a function argument and use the type template argument to preserve its value category
(function template) [edit]
forwards a function argument as if casting it to the value category and constness of the expression of specified type template argument
(function template) [edit]
(C++11)
converts the argument to an xvalue
(function template) [edit]
converts the argument to an xvalue if the move constructor does not throw
(function template) [edit]
(C++17)
obtains a reference to const to its argument
(function template) [edit]
(C++11)
obtains a reference to an object of the template type argument for use in an unevaluated context
(function template) [edit]
converts an enumeration to its underlying type
(function template) [edit]
compares two integer values, ensuring that signed negative numbers are less than unsigned numbers
(function template) [edit]
(C++20)
checks if an integer value is in the range of a given integer type
(function template) [edit]
(C++23)
marks unreachable point of execution
(function) [edit]
creates a pair object of type, determined by the argument types
(function template) [edit]
(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)
lexicographically compares the values in the pair
(function template) [edit]
specializes the std::swap algorithm
(function template) [edit]
accesses an element of a pair
(function template) [edit]

Classes

implements binary tuple, i.e. a pair of values
(class template) [edit]
(C++11)
obtains the number of elements of a tuple-like type
(class template) [edit]
obtains the element types of a tuple-like type
(class template) [edit]
obtains the size of a pair
(class template specialization) [edit]
obtains the type of the elements of pair
(class template specialization) [edit]
implements compile-time sequence of integers
(class template) [edit]
Forward declarations
Defined in header <tuple>
(C++11)
implements fixed size container, which holds elements of possibly different types
(class template) [edit]
Defined in header <variant>
(C++17)
placeholder type for use as the first alternative in a variant of non-default-constructible types
(class) [edit]

Constants

(C++11)
placeholder to skip an element when unpacking a tuple using tie
(constant) [edit]

Tags

piecewise construction tag
(tag)[edit]
in-place construction tag
(tag)[edit]
value construction tag
(tag)[edit]

[edit] Synopsis

#include <compare>
#include <initializer_list>
 
namespace std {
 // swap
 template<class T>
 constexpr void swap(T& a, T& b) noexcept(/* see description */);
 template<class T, size_t N>
 constexpr void swap(T (&a)[N], T (&b)[N]) noexcept(is_nothrow_swappable_v<T>);
 
 // exchange
 template<class T, class U = T>
 constexpr T exchange(T& obj, U&& new_val);
 
 // forward/move
 template<class T>
 constexpr T&& forward(remove_reference_t<T>& t) noexcept;
 template<class T>
 constexpr T&& forward(remove_reference_t<T>&& t) noexcept;
 template<class T, class U>
 constexpr /* see description */ forward_like(U&& x) noexcept;
 template<class T>
 constexpr remove_reference_t<T>&& move(T&&) noexcept;
 template<class T>
 constexpr conditional_t<
 !is_nothrow_move_constructible_v<T> && is_copy_constructible_v<T>, const T&, T&&>
 move_if_noexcept(T& x) noexcept;
 
 // as_const
 template<class T>
 constexpr add_const_t<T>& as_const(T& t) noexcept;
 template<class T>
 void as_const(const T&&) = delete;
 
 // declval
 template<class T>
 add_rvalue_reference_t<T> declval() noexcept; // as unevaluated operand
 
 // integer comparison functions
 template<class T, class U>
 constexpr bool cmp_equal(T t, U u) noexcept;
 template<class T, class U>
 constexpr bool cmp_not_equal(T t, U u) noexcept;
 
 template<class T, class U>
 constexpr bool cmp_less(T t, U u) noexcept;
 template<class T, class U>
 constexpr bool cmp_greater(T t, U u) noexcept;
 template<class T, class U>
 constexpr bool cmp_less_equal(T t, U u) noexcept;
 template<class T, class U>
 constexpr bool cmp_greater_equal(T t, U u) noexcept;
 
 template<class R, class T>
 constexpr bool in_range(T t) noexcept;
 
 // to_underlying
 template<class T>
 constexpr underlying_type_t<T> to_underlying(T value) noexcept;
 
 // unreachable
 [[noreturn]] void unreachable();
 
 // compile-time integer sequences
 template<class T, T...>
 struct integer_sequence;
 template<size_t... I>
 using index_sequence = integer_sequence<size_t, I...>;
 
 template<class T, T N>
 using make_integer_sequence = integer_sequence<T, /* see description */>;
 template<size_t N>
 using make_index_sequence = make_integer_sequence<size_t, N>;
 
 template<class... T>
 using index_sequence_for = make_index_sequence<sizeof...(T)>;
 
 // class template pair
 template<class T1, class T2>
 struct pair;
 
 // pair specialized algorithms
 template<class T1, class T2>
 constexpr bool operator==(const pair<T1, T2>&, const pair<T1, T2>&);
 template<class T1, class T2>
 constexpr common_comparison_category_t</*synth-three-way-result*/<T1>,
 /*synth-three-way-result*/<T2>>
 operator<=>(const pair<T1, T2>&, const pair<T1, T2>&);
 
 template<class T1, class T2>
 constexpr void swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
 
 template<class T1, class T2>
 constexpr /* see description */ make_pair(T1&&, T2&&);
 
 // tuple-like access to pair
 template<class T> struct tuple_size;
 template<size_t I, class T> struct tuple_element;
 
 template<class T1, class T2> struct tuple_size<pair<T1, T2>>;
 template<size_t I, class T1, class T2> struct tuple_element<I, pair<T1, T2>>;
 
 template<size_t I, class T1, class T2>
 constexpr tuple_element_t<I, pair<T1, T2>>& get(pair<T1, T2>&) noexcept;
 template<size_t I, class T1, class T2>
 constexpr tuple_element_t<I, pair<T1, T2>>&& get(pair<T1, T2>&&) noexcept;
 template<size_t I, class T1, class T2>
 constexpr const tuple_element_t<I, pair<T1, T2>>& get(const pair<T1, T2>&) noexcept;
 template<size_t I, class T1, class T2>
 constexpr const tuple_element_t<I, pair<T1, T2>>&& get(const pair<T1, T2>&&) noexcept;
 template<class T1, class T2>
 constexpr T1& get(pair<T1, T2>& p) noexcept;
 template<class T1, class T2>
 constexpr const T1& get(const pair<T1, T2>& p) noexcept;
 template<class T1, class T2>
 constexpr T1&& get(pair<T1, T2>&& p) noexcept;
 template<class T1, class T2>
 constexpr const T1&& get(const pair<T1, T2>&& p) noexcept;
 template<class T2, class T1>
 constexpr T2& get(pair<T1, T2>& p) noexcept;
 template<class T2, class T1>
 constexpr const T2& get(const pair<T1, T2>& p) noexcept;
 template<class T2, class T1>
 constexpr T2&& get(pair<T1, T2>&& p) noexcept;
 template<class T2, class T1>
 constexpr const T2&& get(const pair<T1, T2>&& p) noexcept;
 
 // pair piecewise construction
 struct piecewise_construct_t {
 explicit piecewise_construct_t() = default;
 };
 inline constexpr piecewise_construct_t piecewise_construct{};
 template<class... Types> class tuple; // defined in <tuple>
 
 // in-place construction
 struct in_place_t {
 explicit in_place_t() = default;
 };
 inline constexpr in_place_t in_place{};
 
 template<class T>
 struct in_place_type_t {
 explicit in_place_type_t() = default;
 };
 template<class T> inline constexpr in_place_type_t<T> in_place_type{};
 
 template<size_t I>
 struct in_place_index_t {
 explicit in_place_index_t() = default;
 };
 template<size_t I> inline constexpr in_place_index_t<I> in_place_index{};
 
 // nontype argument tag
 template<auto V>
 struct nontype_t {
 explicit nontype_t() = default;
 };
 template<auto V> inline constexpr nontype_t<V> nontype{};
}
 
// deprecated
namespace std::rel_ops {
 template<class T> bool operator!=(const T&, const T&);
 template<class T> bool operator> (const T&, const T&);
 template<class T> bool operator<=(const T&, const T&);
 template<class T> bool operator>=(const T&, const T&);
}

[edit] Class template std::integer_sequence 

namespace std {
 template<class T, T... I> struct integer_sequence {
 using value_type = T;
 static constexpr size_t size() noexcept { return sizeof...(I); }
 };
}

[edit] Class template std::pair 

namespace std {
 template<class T1, class T2>
 struct pair {
 using first_type = T1;
 using second_type = T2;
 
 T1 first;
 T2 second;
 
 pair(const pair&) = default;
 pair(pair&&) = default;
 constexpr explicit(/* see description */) pair();
 constexpr explicit(/* see description */) pair(const T1& x, const T2& y);
 template<class U1 = T1, class U2 = T2>
 constexpr explicit(/* see description */) pair(U1&& x, U2&& y);
 template<class U1, class U2>
 constexpr explicit(/* see description */) pair(const pair<U1, U2>& p);
 template<class U1, class U2>
 constexpr explicit(/* see description */) pair(pair<U1, U2>&& p);
 template<class... Args1, class... Args2>
 constexpr pair(piecewise_construct_t,
 tuple<Args1...> first_args, tuple<Args2...> second_args);
 
 constexpr pair& operator=(const pair& p);
 template<class U1, class U2>
 constexpr pair& operator=(const pair<U1, U2>& p);
 constexpr pair& operator=(pair&& p) noexcept(/* see description */);
 template<class U1, class U2>
 constexpr pair& operator=(pair<U1, U2>&& p);
 
 constexpr void swap(pair& p) noexcept(/* see description */);
 };
 
 template<class T1, class T2>
 pair(T1, T2) -> pair<T1, T2>;
}

[edit] See also

(C++11)
std::tuple class template[edit]
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/header/utility&oldid=177916"

AltStyle によって変換されたページ (->オリジナル) /