tuple-like, pair-like

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Program utilities Variadic functions initializer_list (C++11) is_constant_evaluated (C++20) is_within_lifetime (C++26) source_location (C++20) Coroutine support (C++20) Contract support (C++26) Three-way comparison three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)   is_eqis_ltis_lteq (C++20)(C++20)(C++20)   is_neqis_gtis_gteq (C++20)(C++20)(C++20)

General utilities Function objects Bit manipulation (C++20) bitset hash (C++11) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator>    rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)   cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23)

 

std::tuple

Member functions

tuple::tuple

tuple::operator=

tuple::swap

Non-member functions

make_tuple

tie

forward_as_tuple

tuple_cat

operator==operator!=operator<operator<=operator>operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

swap(std::tuple)

get(std::tuple)

Helper concepts

tuple-like (C++23)

Helper classes

tuple_size<std::tuple>

tuple_element<std::tuple>

uses_allocator<std::tuple>

basic_common_reference<std::tuple> (C++23)

common_type<std::tuple> (C++23)

formatter<std::tuple> (C++23)

ignore

Deduction guides(C++17)

 

template< class T > concept tuple-like = /* see below */;	(1)	(since C++23) (exposition only*)
template< class T > concept pair-like = tuple-like<T> && std::tuple_size_v<std::remove_cvref_t<T>> == 2;	(2)	(since C++23) (exposition only*)

1) A type T models and satisfies the concept tuple-like if std::remove_cvref_t<T> is a specialization of

• std::array,

std::complex,

(since C++26)

• std::pair,
• std::tuple, or
• std::ranges::subrange.

2) pair-like objects are tuple-like objects with exactly 2 elements.

Notes

tuple-like types implement the tuple protocol, i.e., such types can be used with std::get, std::tuple_element and std::tuple_size.

Elements of tuple-like types can be bound with structured binding.

See also

tuple-like and pair-like are used in the following standard library components:

(constructor)	constructs a new tuple (public member function)
operator=	assigns the contents of one tuple to another (public member function)
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::basic_common_reference<tuple-like> (C++23)	determines the common reference type of a tuple and a tuple-like type (class template specialization)
std::common_type<tuple-like> (C++23)	determines the common type of a tuple and a tuple-like type (class template specialization)
tuple_cat (C++11)	creates a tuple by concatenating any number of tuples (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)
(constructor)	constructs new pair (public member function of std::pair<T1,T2>)
operator=	assigns the contents (public member function of std::pair<T1,T2>)
operator PairLike	converts the subrange to a pair-like type (public member function of std::ranges::subrange<I,S,K>)
ranges::elements_viewviews::elements (C++20)	takes a view consisting of tuple-like values and a number N and produces a view of Nth element of each tuple (class template) (range adaptor object)