std::common_type<tuple-like>

 

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

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Defined in header <tuple>
template< tuple-like TTuple, tuple-like UTuple >     requires /* see below */ struct common_type<TTuple, UTuple>;		(since C++23)

The common type of two tuple-like types is a std::tuple consists of the common types of all corresponding element type pairs of both types.

Given

• TTypes as the pack formed by the sequence of std::tuple_element_t<i, TTuple> for every integer i in [​0, std::tuple_size_v<TTuple>), and
• UTypes as the pack formed by the sequence of std::tuple_element_t<i, UTuple> for every integer i in [​0, std::tuple_size_v<UTuple>),

the following constraints need to be satisfied:

• TTuple or UTuple is a std::tuple specialization.
• std::is_same_v<TTuple, std::decay_t<TTuple>> is true.
• std::is_same_v<UTuple, std::decay_t<UTuple>> is true.
• std::tuple_size_v<TTuple> equals std::tuple_size_v<UTuple> (TTuple and UTuple have the same number of elements).
• std::tuple<std::common_type_t<TTypes, UTypes>...> denotes a type.

Member types

Member type	Definition
type	std::tuple<std::common_type_t<TTypes, UTypes>...>

See also

common_type (C++11)	determines the common type of a group of types (class template)
std::common_type<std::pair> (C++23)	determines the common type of two pairs (class template specialization)