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std::basic_common_reference<tuple-like>

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

The common reference type of two tuple-like types is a std::tuple consists of the common reference types of all corresponding element type pairs of both types, where the cv and reference qualifiers on the tuple-like types are applied to their element 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_reference_t<TQual<TTypes>...,UQual<UTypes>>...> denotes a type.

Member types

Member type Definition
type std::tuple<std::common_reference_t<TQual<TTypes>...,UQual<UTypes>>...>

Example

See also

common_referencebasic_common_reference
(C++20)
determines the common reference type of a group of types
(class template)
std::basic_common_reference<std::pair>
(C++23)
determines the common reference type of two pairs
(class template specialization)

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https://en.cppreference.com/cpp/utility/tuple/basic_common_reference

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