Subclause | Header | |
Utility components | <utility> | |
Compile-time integer sequences | ||
Pairs | ||
Tuples | <tuple> | |
Optional objects | <optional> | |
Variants | <variant> | |
Storage for any type | <any> | |
Fixed-size sequences of bits | <bitset> | |
Memory | <cstdlib>, <memory> | |
Smart pointers | <memory> | |
Memory resources | <memory_resource> | |
Scoped allocators | <scoped_allocator> | |
Function objects | <functional> | |
Type traits | <type_traits> | |
Compile-time rational arithmetic | <ratio> | |
Type indexes | <typeindex> | |
Execution policies | <execution> | |
Primitive numeric conversions | <charconv> | |
Formatting | <format> |
#include <compare> // see [compare.syn] #include <initializer_list> // see [initializer.list.syn] namespace std { // [utility.swap], swap template<class T> constexpr void swap(T& a, T& b) noexcept(see below); template<class T, size_t N> constexpr void swap(T (&a)[N], T (&b)[N]) noexcept(is_nothrow_swappable_v<T>); // [utility.exchange], exchange template<class T, class U = T> constexpr T exchange(T& obj, U&& new_val); // [forward], 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> 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; // [utility.as.const], 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], declval template<class T> add_rvalue_reference_t<T> declval() noexcept; // as unevaluated operand // [utility.intcmp], 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; // [intseq], compile-time integer sequences \indexlibraryglobal{index_sequence}% \indexlibraryglobal{make_index_sequence}% \indexlibraryglobal{index_sequence_for} 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 below>; 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)>; // [pairs], class template pair template<class T1, class T2> struct pair; // [pairs.spec], 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 below make_pair(T1&&, T2&&); // [pair.astuple], 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], 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> ([tuple.syn]) // in-place construction \indexlibraryglobal{in_place_t}% \indexlibraryglobal{in_place}% \indexlibraryglobal{in_place_type_t}% \indexlibraryglobal{in_place_type}% \indexlibraryglobal{in_place_index_t}% \indexlibraryglobal{in_place_index} 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{}; }
template<class T>
constexpr void swap(T& a, T& b) noexcept(see below);
is_nothrow_move_constructible_v<T> && is_nothrow_move_assignable_v<T>
template<class T, size_t N>
constexpr void swap(T (&a)[N], T (&b)[N]) noexcept(is_nothrow_swappable_v<T>);
template<class T, class U = T>
constexpr T exchange(T& obj, U&& new_val);
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 A1, class A2> shared_ptr<T> factory(A1&& a1, A2&& a2) { return shared_ptr<T>(new T(std::forward<A1>(a1), std::forward<A2>(a2))); } struct A { A(int&, const double&); }; void g() { shared_ptr<A> sp1 = factory<A>(2, 1.414); // error: 2 will not bind to int& int i = 2; shared_ptr<A> sp2 = factory<A>(i, 1.414); // OK }
template<class T> constexpr remove_reference_t<T>&& move(T&& t) noexcept;
template<class T, class A1> shared_ptr<T> factory(A1&& a1) { return shared_ptr<T>(new T(std::forward<A1>(a1))); } struct A { A(); A(const A&); // copies from lvalues A(A&&); // moves from rvalues }; void g() { A a; shared_ptr<A> sp1 = factory<A>(a); // “a” binds to A(const A&) shared_ptr<A> sp1 = factory<A>(std::move(a)); // “a” binds to A(A&&) }
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;
template<class T> constexpr add_const_t<T>& as_const(T& t) noexcept;
template<class T> add_rvalue_reference_t<T> declval() noexcept; // as unevaluated operand
template<class T, class U>
constexpr bool cmp_equal(T t, U u) noexcept;
using UT = make_unsigned_t<T>; using UU = make_unsigned_t<U>; if constexpr (is_signed_v<T> == is_signed_v<U>) return t == u; else if constexpr (is_signed_v<T>) return t < 0 ? false : UT(t) == u; else return u < 0 ? false : t == UU(u);
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;
using UT = make_unsigned_t<T>; using UU = make_unsigned_t<U>; if constexpr (is_signed_v<T> == is_signed_v<U>) return t < u; else if constexpr (is_signed_v<T>) return t < 0 ? true : UT(t) < u; else return u < 0 ? false : t < UU(u);
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;
return cmp_greater_equal(t, numeric_limits<R>::min()) && cmp_less_equal(t, numeric_limits<R>::max());
namespace std { template<class T, T... I> struct integer_sequence { using value_type = T; static constexpr size_t size() noexcept { return sizeof...(I); } }; }
template<class T, T N>
using make_integer_sequence = integer_sequence<T, see below>;
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 below) pair(); constexpr explicit(see below) pair(const T1& x, const T2& y); template<class U1, class U2> constexpr explicit(see below) pair(U1&& x, U2&& y); template<class U1, class U2> constexpr explicit(see below) pair(const pair<U1, U2>& p); template<class U1, class U2> constexpr explicit(see below) 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 below); template<class U1, class U2> constexpr pair& operator=(pair<U1, U2>&& p); constexpr void swap(pair& p) noexcept(see below); }; template<class T1, class T2> pair(T1, T2) -> pair<T1, T2>; }
constexpr explicit(see below) pair();
constexpr explicit(see below) pair(const T1& x, const T2& y);
!is_convertible_v<const first_type&, first_type> || !is_convertible_v<const second_type&, second_type>
template<class U1, class U2> constexpr explicit(see below) pair(U1&& x, U2&& y);
!is_convertible_v<U1, first_type> || !is_convertible_v<U2, second_type>
template<class U1, class U2> constexpr explicit(see below) pair(const pair<U1, U2>& p);
!is_convertible_v<const U1&, first_type> || !is_convertible_v<const U2&, second_type>
template<class U1, class U2> constexpr explicit(see below) pair(pair<U1, U2>&& p);
!is_convertible_v<U1, first_type> || !is_convertible_v<U2, second_type>
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 below);
is_nothrow_move_assignable_v<T1> && is_nothrow_move_assignable_v<T2>
template<class U1, class U2> constexpr pair& operator=(pair<U1, U2>&& p);
constexpr void swap(pair& p) noexcept(see below);
template<class T1, class T2>
constexpr bool operator==(const pair<T1, T2>& x, const pair<T1, T2>& y);
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>& x, const pair<T1, T2>& y);
if (auto c = synth-three-way(x.first, y.first); c != 0) return c; return synth-three-way(x.second, y.second);
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 pair<unwrap_ref_decay_t<T1>, unwrap_ref_decay_t<T2>> make_pair(T1&& x, T2&& y);
pair<unwrap_ref_decay_t<T1>, unwrap_ref_decay_t<T2>>(std::forward<T1>(x), std::forward<T2>(y))
template<class T1, class T2>
struct tuple_size<pair<T1, T2>> : integral_constant<size_t, 2> { };
template<size_t I, class T1, class T2>
struct tuple_element<I, pair<T1, T2>> {
using type = see below ;
};
template<size_t I, class T1, class T2>
constexpr tuple_element_t<I, pair<T1, T2>>& get(pair<T1, T2>& p) noexcept;
template<size_t I, class T1, class T2>
constexpr const tuple_element_t<I, pair<T1, T2>>& get(const pair<T1, T2>& p) noexcept;
template<size_t I, class T1, class T2>
constexpr tuple_element_t<I, pair<T1, T2>>&& get(pair<T1, T2>&& p) noexcept;
template<size_t I, class T1, class T2>
constexpr const tuple_element_t<I, pair<T1, T2>>&& 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 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;
struct piecewise_construct_t {
explicit piecewise_construct_t() = default;
};
inline constexpr piecewise_construct_t piecewise_construct{};
#include <compare> // see [compare.syn] namespace std { // [tuple.tuple], class template tuple template<class... Types> class tuple; // [tuple.creation], tuple creation functions inline constexpr unspecified ignore; template<class... TTypes> constexpr tuple<unwrap_ref_decay_t<TTypes>...> make_tuple(TTypes&&...); template<class... TTypes> constexpr tuple<TTypes&&...> forward_as_tuple(TTypes&&...) noexcept; template<class... TTypes> constexpr tuple<TTypes&...> tie(TTypes&...) noexcept; template<class... Tuples> constexpr tuple<CTypes...> tuple_cat(Tuples&&...); // [tuple.apply], calling a function with a tuple of arguments template<class F, class Tuple> constexpr decltype(auto) apply(F&& f, Tuple&& t); template<class T, class Tuple> constexpr T make_from_tuple(Tuple&& t); // [tuple.helper], tuple helper classes template<class T> struct tuple_size; // not defined template<class T> struct tuple_size<const T>; template<class... Types> struct tuple_size<tuple<Types...>>; template<size_t I, class T> struct tuple_element; // not defined template<size_t I, class T> struct tuple_element<I, const T>; template<size_t I, class... Types> struct tuple_element<I, tuple<Types...>>; template<size_t I, class T> using tuple_element_t = typename tuple_element<I, T>::type; // [tuple.elem], element access template<size_t I, class... Types> constexpr tuple_element_t<I, tuple<Types...>>& get(tuple<Types...>&) noexcept; template<size_t I, class... Types> constexpr tuple_element_t<I, tuple<Types...>>&& get(tuple<Types...>&&) noexcept; template<size_t I, class... Types> constexpr const tuple_element_t<I, tuple<Types...>>& get(const tuple<Types...>&) noexcept; template<size_t I, class... Types> constexpr const tuple_element_t<I, tuple<Types...>>&& get(const tuple<Types...>&&) noexcept; template<class T, class... Types> constexpr T& get(tuple<Types...>& t) noexcept; template<class T, class... Types> constexpr T&& get(tuple<Types...>&& t) noexcept; template<class T, class... Types> constexpr const T& get(const tuple<Types...>& t) noexcept; template<class T, class... Types> constexpr const T&& get(const tuple<Types...>&& t) noexcept; // [tuple.rel], relational operators template<class... TTypes, class... UTypes> constexpr bool operator==(const tuple<TTypes...>&, const tuple<UTypes...>&); template<class... TTypes, class... UTypes> constexpr common_comparison_category_t<synth-three-way-result<TTypes, UTypes>...> operator<=>(const tuple<TTypes...>&, const tuple<UTypes...>&); // [tuple.traits], allocator-related traits template<class... Types, class Alloc> struct uses_allocator<tuple<Types...>, Alloc>; // [tuple.special], specialized algorithms template<class... Types> constexpr void swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(see below); // [tuple.helper], tuple helper classes template<class T> inline constexpr size_t tuple_size_v = tuple_size<T>::value; }
namespace std { template<class... Types> class tuple { public: // [tuple.cnstr], tuple construction constexpr explicit(see below) tuple(); constexpr explicit(see below) tuple(const Types&...); // only if sizeof...(Types) >= 1 template<class... UTypes> constexpr explicit(see below) tuple(UTypes&&...); // only if sizeof...(Types) >= 1 tuple(const tuple&) = default; tuple(tuple&&) = default; template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>&); template<class... UTypes> constexpr explicit(see below) tuple(tuple<UTypes...>&&); template<class U1, class U2> constexpr explicit(see below) tuple(const pair<U1, U2>&); // only if sizeof...(Types) == 2 template<class U1, class U2> constexpr explicit(see below) tuple(pair<U1, U2>&&); // only if sizeof...(Types) == 2 // allocator-extended constructors template<class Alloc> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a); template<class Alloc> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, const Types&...); template<class Alloc, class... UTypes> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, UTypes&&...); template<class Alloc> constexpr tuple(allocator_arg_t, const Alloc& a, const tuple&); template<class Alloc> constexpr tuple(allocator_arg_t, const Alloc& a, tuple&&); template<class Alloc, class... UTypes> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&); template<class Alloc, class... UTypes> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&&); template<class Alloc, class U1, class U2> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&); template<class Alloc, class U1, class U2> constexpr explicit(see below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&); // [tuple.assign], tuple assignment constexpr tuple& operator=(const tuple&); constexpr tuple& operator=(tuple&&) noexcept(see below); template<class... UTypes> constexpr tuple& operator=(const tuple<UTypes...>&); template<class... UTypes> constexpr tuple& operator=(tuple<UTypes...>&&); template<class U1, class U2> constexpr tuple& operator=(const pair<U1, U2>&); // only if sizeof...(Types) == 2 template<class U1, class U2> constexpr tuple& operator=(pair<U1, U2>&&); // only if sizeof...(Types) == 2 // [tuple.swap], tuple swap constexpr void swap(tuple&) noexcept(see below); }; template<class... UTypes> tuple(UTypes...) -> tuple<UTypes...>; template<class T1, class T2> tuple(pair<T1, T2>) -> tuple<T1, T2>; template<class Alloc, class... UTypes> tuple(allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>; template<class Alloc, class T1, class T2> tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>; template<class Alloc, class... UTypes> tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>; }
constexpr explicit(see below) tuple();
constexpr explicit(see below) tuple(const Types&...);
!conjunction_v<is_convertible<const Types&, Types>...>
template<class... UTypes> constexpr explicit(see below) tuple(UTypes&&... u);
!conjunction_v<is_convertible<UTypes, Types>...>
tuple(const tuple& u) = default;
tuple(tuple&& u) = default;
template<class... UTypes> constexpr explicit(see below) tuple(const tuple<UTypes...>& u);
!conjunction_v<is_convertible<const UTypes&, Types>...>
template<class... UTypes> constexpr explicit(see below) tuple(tuple<UTypes...>&& u);
!conjunction_v<is_convertible<UTypes, Types>...>
template<class U1, class U2> constexpr explicit(see below) tuple(const pair<U1, U2>& u);
!is_convertible_v<const U1&, > || !is_convertible_v<const U2&, >
template<class U1, class U2> constexpr explicit(see below) tuple(pair<U1, U2>&& u);
!is_convertible_v<U1, > || !is_convertible_v<U2, >
template<class Alloc>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a);
template<class Alloc>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, const Types&...);
template<class Alloc, class... UTypes>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, UTypes&&...);
template<class Alloc>
constexpr tuple(allocator_arg_t, const Alloc& a, const tuple&);
template<class Alloc>
constexpr tuple(allocator_arg_t, const Alloc& a, tuple&&);
template<class Alloc, class... UTypes>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&);
template<class Alloc, class... UTypes>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&&);
template<class Alloc, class U1, class U2>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);
template<class Alloc, class U1, class U2>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);
constexpr tuple& operator=(const tuple& u);
constexpr tuple& operator=(tuple&& u) noexcept(see below);
template<class... UTypes> constexpr tuple& operator=(const tuple<UTypes...>& u);
template<class... UTypes> constexpr tuple& operator=(tuple<UTypes...>&& u);
template<class U1, class U2> constexpr tuple& operator=(const pair<U1, U2>& u);
template<class U1, class U2> constexpr tuple& operator=(pair<U1, U2>&& u);
constexpr void swap(tuple& rhs) noexcept(see below);
template<class... TTypes>
constexpr tuple<unwrap_ref_decay_t<TTypes>...> make_tuple(TTypes&&... t);
template<class... TTypes>
constexpr tuple<TTypes&&...> forward_as_tuple(TTypes&&... t) noexcept;
template<class... TTypes>
constexpr tuple<TTypes&...> tie(TTypes&... t) noexcept;
template<class... Tuples>
constexpr tuple<CTypes...> tuple_cat(Tuples&&... tpls);
template<class F, class Tuple>
constexpr decltype(auto) apply(F&& f, Tuple&& t);
template<class F, class Tuple, size_t... I> constexpr decltype(auto) apply-impl(F&& f, Tuple&& t, index_sequence<I...>) { // exposition only return INVOKE(std::forward<F>(f), std::get<I>(std::forward<Tuple>(t))...); // see [func.require] }
return apply-impl(std::forward<F>(f), std::forward<Tuple>(t), make_index_sequence<tuple_size_v<remove_reference_t<Tuple>>>{});
template<class T, class Tuple>
constexpr T make_from_tuple(Tuple&& t);
template<class T, class Tuple, size_t... I> constexpr T make-from-tuple-impl(Tuple&& t, index_sequence<I...>) { // exposition only return T(get<I>(std::forward<Tuple>(t))...); }
return make-from-tuple-impl<T>( forward<Tuple>(t), make_index_sequence<tuple_size_v<remove_reference_t<Tuple>>>{});
template<class T> struct tuple_size;
template<class... Types>
struct tuple_size<tuple<Types...>> : public integral_constant<size_t, sizeof...(Types)> { };
template<size_t I, class... Types>
struct tuple_element<I, tuple<Types...>> {
using type = TI;
};
template<class T> struct tuple_size<const T>;
integral_constant<size_t, TS::value>
template<size_t I, class T> struct tuple_element<I, const T>;
template<size_t I, class... Types>
constexpr tuple_element_t<I, tuple<Types...>>&
get(tuple<Types...>& t) noexcept;
template<size_t I, class... Types>
constexpr tuple_element_t<I, tuple<Types...>>&&
get(tuple<Types...>&& t) noexcept; // Note A
template<size_t I, class... Types>
constexpr const tuple_element_t<I, tuple<Types...>>&
get(const tuple<Types...>& t) noexcept; // Note B
template<size_t I, class... Types>
constexpr const tuple_element_t<I, tuple<Types...>>&& get(const tuple<Types...>&& t) noexcept;
template<class T, class... Types>
constexpr T& get(tuple<Types...>& t) noexcept;
template<class T, class... Types>
constexpr T&& get(tuple<Types...>&& t) noexcept;
template<class T, class... Types>
constexpr const T& get(const tuple<Types...>& t) noexcept;
template<class T, class... Types>
constexpr const T&& get(const tuple<Types...>&& t) noexcept;
template<class... TTypes, class... UTypes>
constexpr bool operator==(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
template<class... TTypes, class... UTypes>
constexpr common_comparison_category_t<synth-three-way-result<TTypes, UTypes>...>
operator<=>(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
if (auto c = synth-three-way(get<0>(t), get<0>(u)); c != 0) return c; return <=> ;where for some tuple r is a tuple containing all but the first element of r.
template<class... Types, class Alloc>
struct uses_allocator<tuple<Types...>, Alloc> : true_type { };
template<class... Types>
constexpr void swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(see below);
#include <compare> // see [compare.syn] namespace std { // [optional.optional], class template optional template<class T> class optional; // [optional.nullopt], no-value state indicator struct nullopt_t{see below}; inline constexpr nullopt_t nullopt(unspecified); // [optional.bad.access], class bad_optional_access class bad_optional_access; // [optional.relops], relational operators template<class T, class U> constexpr bool operator==(const optional<T>&, const optional<U>&); template<class T, class U> constexpr bool operator!=(const optional<T>&, const optional<U>&); template<class T, class U> constexpr bool operator<(const optional<T>&, const optional<U>&); template<class T, class U> constexpr bool operator>(const optional<T>&, const optional<U>&); template<class T, class U> constexpr bool operator<=(const optional<T>&, const optional<U>&); template<class T, class U> constexpr bool operator>=(const optional<T>&, const optional<U>&); template<class T, three_way_comparable_with<T> U> constexpr compare_three_way_result_t<T,U> operator<=>(const optional<T>&, const optional<U>&); // [optional.nullops], comparison with nullopt template<class T> constexpr bool operator==(const optional<T>&, nullopt_t) noexcept; template<class T> constexpr strong_ordering operator<=>(const optional<T>&, nullopt_t) noexcept; // [optional.comp.with.t], comparison with T template<class T, class U> constexpr bool operator==(const optional<T>&, const U&); template<class T, class U> constexpr bool operator==(const T&, const optional<U>&); template<class T, class U> constexpr bool operator!=(const optional<T>&, const U&); template<class T, class U> constexpr bool operator!=(const T&, const optional<U>&); template<class T, class U> constexpr bool operator<(const optional<T>&, const U&); template<class T, class U> constexpr bool operator<(const T&, const optional<U>&); template<class T, class U> constexpr bool operator>(const optional<T>&, const U&); template<class T, class U> constexpr bool operator>(const T&, const optional<U>&); template<class T, class U> constexpr bool operator<=(const optional<T>&, const U&); template<class T, class U> constexpr bool operator<=(const T&, const optional<U>&); template<class T, class U> constexpr bool operator>=(const optional<T>&, const U&); template<class T, class U> constexpr bool operator>=(const T&, const optional<U>&); template<class T, three_way_comparable_with<T> U> constexpr compare_three_way_result_t<T,U> operator<=>(const optional<T>&, const U&); // [optional.specalg], specialized algorithms template<class T> void swap(optional<T>&, optional<T>&) noexcept(see below); template<class T> constexpr optional<see below> make_optional(T&&); template<class T, class... Args> constexpr optional<T> make_optional(Args&&... args); template<class T, class U, class... Args> constexpr optional<T> make_optional(initializer_list<U> il, Args&&... args); // [optional.hash], hash support template<class T> struct hash; template<class T> struct hash<optional<T>>; }
namespace std { template<class T> class optional { public: using value_type = T; // [optional.ctor], constructors constexpr optional() noexcept; constexpr optional(nullopt_t) noexcept; constexpr optional(const optional&); constexpr optional(optional&&) noexcept(see below); template<class... Args> constexpr explicit optional(in_place_t, Args&&...); template<class U, class... Args> constexpr explicit optional(in_place_t, initializer_list<U>, Args&&...); template<class U = T> constexpr explicit(see below) optional(U&&); template<class U> explicit(see below) optional(const optional<U>&); template<class U> explicit(see below) optional(optional<U>&&); // [optional.dtor], destructor ~optional(); // [optional.assign], assignment optional& operator=(nullopt_t) noexcept; constexpr optional& operator=(const optional&); constexpr optional& operator=(optional&&) noexcept(see below); template<class U = T> optional& operator=(U&&); template<class U> optional& operator=(const optional<U>&); template<class U> optional& operator=(optional<U>&&); template<class... Args> T& emplace(Args&&...); template<class U, class... Args> T& emplace(initializer_list<U>, Args&&...); // [optional.swap], swap void swap(optional&) noexcept(see below); // [optional.observe], observers constexpr const T* operator->() const; constexpr T* operator->(); constexpr const T& operator*() const&; constexpr T& operator*() &; constexpr T&& operator*() &&; constexpr const T&& operator*() const&&; constexpr explicit operator bool() const noexcept; constexpr bool has_value() const noexcept; constexpr const T& value() const&; constexpr T& value() &; constexpr T&& value() &&; constexpr const T&& value() const&&; template<class U> constexpr T value_or(U&&) const&; template<class U> constexpr T value_or(U&&) &&; // [optional.mod], modifiers void reset() noexcept; private: T *val; // exposition only }; template<class T> optional(T) -> optional<T>; }
constexpr optional() noexcept;
constexpr optional(nullopt_t) noexcept;
constexpr optional(const optional& rhs);
constexpr optional(optional&& rhs) noexcept(see below);
template<class... Args> constexpr explicit optional(in_place_t, Args&&... args);
template<class U, class... Args>
constexpr explicit optional(in_place_t, initializer_list<U> il, Args&&... args);
template<class U = T> constexpr explicit(see below) optional(U&& v);
template<class U> explicit(see below) optional(const optional<U>& rhs);
template<class U> explicit(see below) optional(optional<U>&& rhs);
~optional();
val->T::~T()
optional<T>& operator=(nullopt_t) noexcept;
constexpr optional<T>& operator=(const optional& rhs);
*this contains a value | *this does not contain a value | ||
rhs contains a value | assigns *rhs to the contained value | initializes the contained value as if direct-non-list-initializing an object of type T with *rhs | |
rhs does not contain a value | destroys the contained value by calling val->T::~T() | no effect |
constexpr optional& operator=(optional&& rhs) noexcept(see below);
*this contains a value | *this does not contain a value | ||
rhs contains a value | assigns std::move(*rhs) to the contained value | initializes the contained value as if direct-non-list-initializing an object of type T with std::move(*rhs) | |
rhs does not contain a value | destroys the contained value by calling val->T::~T() | no effect |
is_nothrow_move_assignable_v<T> && is_nothrow_move_constructible_v<T>
template<class U = T> optional<T>& operator=(U&& v);
template<class U> optional<T>& operator=(const optional<U>& rhs);
*this contains a value | *this does not contain a value | ||
rhs contains a value | assigns *rhs to the contained value | initializes the contained value as if direct-non-list-initializing
an object of type T with *rhs | |
rhs does not contain a value | destroys the contained value by calling val->T::~T() | no effect |
template<class U> optional<T>& operator=(optional<U>&& rhs);
*this contains a value | *this does not contain a value | ||
rhs contains a value | assigns std::move(*rhs) to the contained value | initializes the contained value as if direct-non-list-initializing
an object of type T with std::move(*rhs) | |
rhs does not contain a value | destroys the contained value by calling val->T::~T() | no effect |
template<class... Args> T& emplace(Args&&... args);
template<class U, class... Args> T& emplace(initializer_list<U> il, Args&&... args);
void swap(optional& rhs) noexcept(see below);
*this contains a value | *this does not contain a value | ||
rhs contains a value | calls swap(*(*this), *rhs) | initializes the contained value of *this as if
direct-non-list-initializing an object of type T with the expression std::move(*rhs),
followed by rhs.val->T::~T();
postcondition is that *this contains a value and rhs does not contain a value | |
rhs does not contain a value | initializes the contained value of rhs as if
direct-non-list-initializing an object of type T with the expression std::move(*(*this)),
followed by val->T::~T();
postcondition is that *this does not contain a value and rhs contains a value | no effect |
is_nothrow_move_constructible_v<T> && is_nothrow_swappable_v<T>
constexpr const T* operator->() const;
constexpr T* operator->();
constexpr const T& operator*() const&;
constexpr T& operator*() &;
constexpr T&& operator*() &&;
constexpr const T&& operator*() const&&;
constexpr explicit operator bool() const noexcept;
constexpr bool has_value() const noexcept;
constexpr const T& value() const&;
constexpr T& value() &;
constexpr T&& value() &&;
constexpr const T&& value() const&&;
template<class U> constexpr T value_or(U&& v) const&;
template<class U> constexpr T value_or(U&& v) &&;
struct nullopt_t{see below};
inline constexpr nullopt_t nullopt(unspecified);
class bad_optional_access : public exception { public: // see [exception] for the specification of the special member functions const char* what() const noexcept override; };
const char* what() const noexcept override;
template<class T, class U> constexpr bool operator==(const optional<T>& x, const optional<U>& y);
template<class T, class U> constexpr bool operator!=(const optional<T>& x, const optional<U>& y);
template<class T, class U> constexpr bool operator<(const optional<T>& x, const optional<U>& y);
template<class T, class U> constexpr bool operator>(const optional<T>& x, const optional<U>& y);
template<class T, class U> constexpr bool operator<=(const optional<T>& x, const optional<U>& y);
template<class T, class U> constexpr bool operator>=(const optional<T>& x, const optional<U>& y);
template<class T> constexpr bool operator==(const optional<T>& x, nullopt_t) noexcept;
template<class T> constexpr strong_ordering operator<=>(const optional<T>& x, nullopt_t) noexcept;
template<class T, class U> constexpr bool operator==(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator==(const T& v, const optional<U>& x);
template<class T, class U> constexpr bool operator!=(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator!=(const T& v, const optional<U>& x);
template<class T, class U> constexpr bool operator<(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator<(const T& v, const optional<U>& x);
template<class T, class U> constexpr bool operator>(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator>(const T& v, const optional<U>& x);
template<class T, class U> constexpr bool operator<=(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator<=(const T& v, const optional<U>& x);
template<class T, class U> constexpr bool operator>=(const optional<T>& x, const U& v);
template<class T, class U> constexpr bool operator>=(const T& v, const optional<U>& x);
template<class T> void swap(optional<T>& x, optional<T>& y) noexcept(noexcept(x.swap(y)));
template<class T> constexpr optional<decay_t<T>> make_optional(T&& v);
template<class T, class...Args>
constexpr optional<T> make_optional(Args&&... args);
template<class T, class U, class... Args>
constexpr optional<T> make_optional(initializer_list<U> il, Args&&... args);
template<class T> struct hash<optional<T>>;
#include <compare> // see [compare.syn] namespace std { // [variant.variant], class template variant template<class... Types> class variant; // [variant.helper], variant helper classes template<class T> struct variant_size; // not defined template<class T> struct variant_size<const T>; template<class T> inline constexpr size_t variant_size_v = variant_size<T>::value; template<class... Types> struct variant_size<variant<Types...>>; template<size_t I, class T> struct variant_alternative; // not defined template<size_t I, class T> struct variant_alternative<I, const T>; template<size_t I, class T> using variant_alternative_t = typename variant_alternative<I, T>::type; template<size_t I, class... Types> struct variant_alternative<I, variant<Types...>>; inline constexpr size_t variant_npos = -1; // [variant.get], value access template<class T, class... Types> constexpr bool holds_alternative(const variant<Types...>&) noexcept; template<size_t I, class... Types> constexpr variant_alternative_t<I, variant<Types...>>& get(variant<Types...>&); template<size_t I, class... Types> constexpr variant_alternative_t<I, variant<Types...>>&& get(variant<Types...>&&); template<size_t I, class... Types> constexpr const variant_alternative_t<I, variant<Types...>>& get(const variant<Types...>&); template<size_t I, class... Types> constexpr const variant_alternative_t<I, variant<Types...>>&& get(const variant<Types...>&&); template<class T, class... Types> constexpr T& get(variant<Types...>&); template<class T, class... Types> constexpr T&& get(variant<Types...>&&); template<class T, class... Types> constexpr const T& get(const variant<Types...>&); template<class T, class... Types> constexpr const T&& get(const variant<Types...>&&); template<size_t I, class... Types> constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>> get_if(variant<Types...>*) noexcept; template<size_t I, class... Types> constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>> get_if(const variant<Types...>*) noexcept; template<class T, class... Types> constexpr add_pointer_t<T> get_if(variant<Types...>*) noexcept; template<class T, class... Types> constexpr add_pointer_t<const T> get_if(const variant<Types...>*) noexcept; // [variant.relops], relational operators template<class... Types> constexpr bool operator==(const variant<Types...>&, const variant<Types...>&); template<class... Types> constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&); template<class... Types> constexpr bool operator<(const variant<Types...>&, const variant<Types...>&); template<class... Types> constexpr bool operator>(const variant<Types...>&, const variant<Types...>&); template<class... Types> constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&); template<class... Types> constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&); template<class... Types> requires (three_way_comparable<Types> && ...) constexpr common_comparison_category_t<compare_three_way_result_t<Types>...> operator<=>(const variant<Types...>&, const variant<Types...>&); // [variant.visit], visitation template<class Visitor, class... Variants> constexpr see below visit(Visitor&&, Variants&&...); template<class R, class Visitor, class... Variants> constexpr R visit(Visitor&&, Variants&&...); // [variant.monostate], class monostate struct monostate; // [variant.monostate.relops], monostate relational operators constexpr bool operator==(monostate, monostate) noexcept; constexpr strong_ordering operator<=>(monostate, monostate) noexcept; // [variant.specalg], specialized algorithms template<class... Types> void swap(variant<Types...>&, variant<Types...>&) noexcept(see below); // [variant.bad.access], class bad_variant_access class bad_variant_access; // [variant.hash], hash support template<class T> struct hash; template<class... Types> struct hash<variant<Types...>>; template<> struct hash<monostate>; }
namespace std { template<class... Types> class variant { public: // [variant.ctor], constructors constexpr variant() noexcept(see below); constexpr variant(const variant&); constexpr variant(variant&&) noexcept(see below); template<class T> constexpr variant(T&&) noexcept(see below); template<class T, class... Args> constexpr explicit variant(in_place_type_t<T>, Args&&...); template<class T, class U, class... Args> constexpr explicit variant(in_place_type_t<T>, initializer_list<U>, Args&&...); template<size_t I, class... Args> constexpr explicit variant(in_place_index_t<I>, Args&&...); template<size_t I, class U, class... Args> constexpr explicit variant(in_place_index_t<I>, initializer_list<U>, Args&&...); // [variant.dtor], destructor ~variant(); // [variant.assign], assignment constexpr variant& operator=(const variant&); constexpr variant& operator=(variant&&) noexcept(see below); template<class T> variant& operator=(T&&) noexcept(see below); // [variant.mod], modifiers template<class T, class... Args> T& emplace(Args&&...); template<class T, class U, class... Args> T& emplace(initializer_list<U>, Args&&...); template<size_t I, class... Args> variant_alternative_t<I, variant<Types...>>& emplace(Args&&...); template<size_t I, class U, class... Args> variant_alternative_t<I, variant<Types...>>& emplace(initializer_list<U>, Args&&...); // [variant.status], value status constexpr bool valueless_by_exception() const noexcept; constexpr size_t index() const noexcept; // [variant.swap], swap void swap(variant&) noexcept(see below); }; }
constexpr variant() noexcept(see below);
constexpr variant(const variant& w);
constexpr variant(variant&& w) noexcept(see below);
template<class T> constexpr variant(T&& t) noexcept(see below);
variant<string, string> v("abc");is ill-formed, as both alternative types have an equally viable constructor for the argument. — end note
template<class T, class... Args> constexpr explicit variant(in_place_type_t<T>, Args&&... args);
template<class T, class U, class... Args>
constexpr explicit variant(in_place_type_t<T>, initializer_list<U> il, Args&&... args);
template<size_t I, class... Args> constexpr explicit variant(in_place_index_t<I>, Args&&... args);
template<size_t I, class U, class... Args>
constexpr explicit variant(in_place_index_t<I>, initializer_list<U> il, Args&&... args);
constexpr variant& operator=(const variant& rhs);
constexpr variant& operator=(variant&& rhs) noexcept(see below);
template<class T> variant& operator=(T&& t) noexcept(see below);
variant<string, string> v; v = "abc";is ill-formed, as both alternative types have an equally viable constructor for the argument. — end note
is_nothrow_assignable_v<T&, T> && is_nothrow_constructible_v<T, T>
template<class T, class... Args> T& emplace(Args&&... args);
template<class T, class U, class... Args> T& emplace(initializer_list<U> il, Args&&... args);
template<size_t I, class... Args>
variant_alternative_t<I, variant<Types...>>& emplace(Args&&... args);
template<size_t I, class U, class... Args>
variant_alternative_t<I, variant<Types...>>& emplace(initializer_list<U> il, Args&&... args);
constexpr bool valueless_by_exception() const noexcept;
struct S { operator int() { throw 42; }}; variant<float, int> v{12.f}; v.emplace<1>(S());
constexpr size_t index() const noexcept;
void swap(variant& rhs) noexcept(see below);
template<class T> struct variant_size;
template<class T> class variant_size<const T>;
template<class... Types>
struct variant_size<variant<Types...>> : integral_constant<size_t, sizeof...(Types)> { };
template<size_t I, class T> class variant_alternative<I, const T>;
variant_alternative<I, variant<Types...>>::type
template<class T, class... Types>
constexpr bool holds_alternative(const variant<Types...>& v) noexcept;
template<size_t I, class... Types>
constexpr variant_alternative_t<I, variant<Types...>>& get(variant<Types...>& v);
template<size_t I, class... Types>
constexpr variant_alternative_t<I, variant<Types...>>&& get(variant<Types...>&& v);
template<size_t I, class... Types>
constexpr const variant_alternative_t<I, variant<Types...>>& get(const variant<Types...>& v);
template<size_t I, class... Types>
constexpr const variant_alternative_t<I, variant<Types...>>&& get(const variant<Types...>&& v);
template<class T, class... Types> constexpr T& get(variant<Types...>& v);
template<class T, class... Types> constexpr T&& get(variant<Types...>&& v);
template<class T, class... Types> constexpr const T& get(const variant<Types...>& v);
template<class T, class... Types> constexpr const T&& get(const variant<Types...>&& v);
template<size_t I, class... Types>
constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
get_if(variant<Types...>* v) noexcept;
template<size_t I, class... Types>
constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
get_if(const variant<Types...>* v) noexcept;
template<class T, class... Types>
constexpr add_pointer_t<T>
get_if(variant<Types...>* v) noexcept;
template<class T, class... Types>
constexpr add_pointer_t<const T>
get_if(const variant<Types...>* v) noexcept;
template<class... Types>
constexpr bool operator==(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types>
constexpr bool operator!=(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types>
constexpr bool operator<(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types>
constexpr bool operator>(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types>
constexpr bool operator<=(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types>
constexpr bool operator>=(const variant<Types...>& v, const variant<Types...>& w);
template<class... Types> requires (three_way_comparable<Types> && ...)
constexpr common_comparison_category_t<compare_three_way_result_t<Types>...>
operator<=>(const variant<Types...>& v, const variant<Types...>& w);
if (v.valueless_by_exception() && w.valueless_by_exception()) return strong_ordering::equal; if (v.valueless_by_exception()) return strong_ordering::less; if (w.valueless_by_exception()) return strong_ordering::greater; if (auto c = v.index() <=> w.index(); c != 0) return c; return get<i>(v) <=> get<i>(w);with i being v.index().
template<class Visitor, class... Variants>
constexpr see below visit(Visitor&& vis, Variants&&... vars);
template<class R, class Visitor, class... Variants>
constexpr R visit(Visitor&& vis, Variants&&... vars);
INVOKE(std::forward<Visitor>(vis), get<m>(std::forward<Variants>(vars))...) // see [func.require]for the first form and
INVOKE<R>(std::forward<Visitor>(vis), get<m>(std::forward<Variants>(vars))...) // see [func.require]for the second form.
struct monostate{};
constexpr bool operator==(monostate, monostate) noexcept { return true; }
constexpr strong_ordering operator<=>(monostate, monostate) noexcept
{ return strong_ordering::equal; }
template<class... Types>
void swap(variant<Types...>& v, variant<Types...>& w) noexcept(see below);
class bad_variant_access : public exception { public: // see [exception] for the specification of the special member functions const char* what() const noexcept override; };
const char* what() const noexcept override;
template<class... Types> struct hash<variant<Types...>>;
template<> struct hash<monostate>;
namespace std { // [any.bad.any.cast], class bad_any_cast class bad_any_cast; // [any.class], class any class any; // [any.nonmembers], non-member functions void swap(any& x, any& y) noexcept; template<class T, class... Args> any make_any(Args&&... args); template<class T, class U, class... Args> any make_any(initializer_list<U> il, Args&&... args); template<class T> T any_cast(const any& operand); template<class T> T any_cast(any& operand); template<class T> T any_cast(any&& operand); template<class T> const T* any_cast(const any* operand) noexcept; template<class T> T* any_cast(any* operand) noexcept; }
class bad_any_cast : public bad_cast { public: // see [exception] for the specification of the special member functions const char* what() const noexcept override; };
const char* what() const noexcept override;
namespace std { class any { public: // [any.cons], construction and destruction constexpr any() noexcept; any(const any& other); any(any&& other) noexcept; template<class T> any(T&& value); template<class T, class... Args> explicit any(in_place_type_t<T>, Args&&...); template<class T, class U, class... Args> explicit any(in_place_type_t<T>, initializer_list<U>, Args&&...); ~any(); // [any.assign], assignments any& operator=(const any& rhs); any& operator=(any&& rhs) noexcept; template<class T> any& operator=(T&& rhs); // [any.modifiers], modifiers template<class T, class... Args> decay_t<T>& emplace(Args&&...); template<class T, class U, class... Args> decay_t<T>& emplace(initializer_list<U>, Args&&...); void reset() noexcept; void swap(any& rhs) noexcept; // [any.observers], observers bool has_value() const noexcept; const type_info& type() const noexcept; }; }