Standard library header <tuple> (C++11)

 

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Standard library headers

Language support <cfloat> <climits> <compare>(C++20) <contracts>(C++26) <coroutine>(C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint>(C++11) <cstdlib> <exception> <initializer_list>(C++11)    <limits> <new> <source_location>(C++20) <stdfloat>(C++23) <typeinfo> <version>(C++20) Concepts <concepts>(C++20) Diagnostics <cassert> <cerrno> <debugging>(C++26) <stacktrace>(C++23) <stdexcept> <system_error>(C++11) Memory management <memory> <memory_resource>(C++17) <scoped_allocator>(C++11) Metaprogramming <type_traits>(C++11) <ratio>(C++11)

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)

Algorithms <algorithm> <numeric> Strings <cctype> <cstring> <cuchar>(C++11) <cwchar> <cwctype> <string_view>(C++17) <string> Text processing <clocale> <codecvt>(C++11/17/26*) <locale> <regex>(C++11) <text_encoding>(C++26)    Numerics <cfenv>(C++11) <cmath> <complex> <linalg>(C++26) <numbers>(C++20) <random>(C++11) <simd>(C++26) <stdckdint.h>(C++26) <valarray> Time <chrono>(C++11) <ctime> C compatibility <ccomplex>(C++11/17/20*) <ciso646>(until C++20) <cstdalign>(C++11/17/20*) <cstdbool>(C++11/17/20*) <ctgmath>(C++11/17/20*)

Input/output <cinttypes>(C++11) <cstdio> <filesystem>(C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print>(C++23) <spanstream>(C++23) <sstream> <streambuf> <strstream>(C++98/26*) <syncstream>(C++20) Concurrency support <atomic>(C++11) <barrier>(C++20) <condition_variable>(C++11) <future>(C++11) <hazard_pointer>(C++26) <latch>(C++20) <mutex>(C++11) <rcu>(C++26) <semaphore>(C++20) <shared_mutex>(C++14) <stdatomic.h>(C++23) <stop_token>(C++20) <thread>(C++11) Execution support <execution>(C++17)

 

This header is part of the general utility library.

Includes
<compare> (C++20)	Three-way comparison operator support
Classes
tuple (C++11)	implements fixed size container, which holds elements of possibly different types (class template)
tuple_size (C++11)	obtains the number of elements of a tuple-like type (class template)
tuple_element (C++11)	obtains the element types of a tuple-like type (class template)
std::tuple_size<std::tuple> (C++11)	obtains the size of a tuple (class template specialization)
std::tuple_element<std::tuple> (C++11)	obtains the type of the specified element (class template specialization)
std::uses_allocator<std::tuple> (C++11)	specializes the std::uses_allocator type trait (class template specialization)
Constants
ignore (C++11)	placeholder to skip an element when unpacking a tuple using tie (constant)
Functions
make_tuple (C++11)	creates a tuple object of the type defined by the argument types (function template)
tie (C++11)	creates a tuple of lvalue references or unpacks a tuple into individual objects (function template)
forward_as_tuple (C++11)	creates a tuple of forwarding references (function template)
tuple_cat (C++11)	creates a tuple by concatenating any number of tuples (function template)
get(std::tuple) (C++11)	tuple accesses specified element (function template)
operator==operator!=operator<operator<=operator>operator>=operator<=> (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 tuple (function template)
std::swap(std::tuple) (C++11)	specializes the std::swap algorithm (function template)
apply (C++17)	calls a function with a tuple of arguments (function template)
make_from_tuple (C++17)	construct an object with a tuple of arguments (function template)

Synopsis

#include <compare>   namespace std {// class template tupletemplate<class... Types>class tuple;   // tuple creation functionsinlineconstexpr/* 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&&...);   // calling a function with a tuple of argumentstemplate<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 classestemplate<class T>struct tuple_size;// not definedtemplate<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 definedtemplate<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;   // element accesstemplate<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>constexprconst tuple_element_t<I, tuple<Types...>>& get(const tuple<Types...>&)noexcept;template<size_t I, class... Types>constexprconst 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>constexprconst T& get(const tuple<Types...>& t)noexcept;template<class T, class... Types>constexprconst T&& get(const tuple<Types...>&& t)noexcept;   // relational operatorstemplate<class... TTypes, class... UTypes>constexprbool 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...>&);   // allocator-related traitstemplate<class... Types, class Alloc>struct uses_allocator<tuple<Types...>, Alloc>;   // specialized algorithmstemplate<class... Types>constexprvoid swap(tuple<Types...>& x, tuple<Types...>& y)noexcept(/* see description */);   // tuple helper classestemplate<class T>inlineconstexpr size_t tuple_size_v = tuple_size<T>::value;}   // deprecatednamespace std {template<class T>class tuple_size<volatile T>;template<class T>class tuple_size<constvolatile T>;   template<size_t I, class T>class tuple_element<I, volatile T>;template<size_t I, class T>class tuple_element<I, constvolatile T>;}

Class template std::tuple

namespace std {template<class... Types>class tuple {public:// tuple constructionconstexprexplicit(/* see description */) tuple();constexprexplicit(/* see description */) tuple(const Types&...);// only if sizeof...(Types) >= 1template<class... UTypes>constexprexplicit(/* see description */) tuple(UTypes&&...);// only if sizeof...(Types) >= 1   tuple(const tuple&)=default; tuple(tuple&&)=default;   template<class... UTypes>constexprexplicit(/* see description */) tuple(const tuple<UTypes...>&);template<class... UTypes>constexprexplicit(/* see description */) tuple(tuple<UTypes...>&&);   template<class U1, class U2>constexprexplicit(/* see description */) tuple(const pair<U1, U2>&);// only if sizeof...(Types) == 2template<class U1, class U2>constexprexplicit(/* see description */) tuple(pair<U1, U2>&&);// only if sizeof...(Types) == 2   // allocator-extended constructorstemplate<class Alloc>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a);template<class Alloc>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a, const Types&...);template<class Alloc, class... UTypes>constexprexplicit(/* see description */) 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>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&);template<class Alloc, class... UTypes>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&&);template<class Alloc, class U1, class U2>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);template<class Alloc, class U1, class U2>constexprexplicit(/* see description */) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);   // tuple assignmentconstexpr tuple& operator=(const tuple&);constexpr tuple& operator=(tuple&&)noexcept(/* see description */);   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) == 2template<class U1, class U2>constexpr tuple& operator=(pair<U1, U2>&&);// only if sizeof...(Types) == 2   // tuple swapconstexprvoid swap(tuple&)noexcept(/* see description */);};   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...>;}