std::type_identity
Defined in header <type_traits>
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template< class T > struct type_identity; |
(since C++20) | |
Provides the member typedef type
that names T
(i.e., the identity transformation).
Member types
Name | Definition |
type
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T
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Helper types
template< class T > using type_identity_t = typename type_identity<T>::type; |
(since C++20) | |
Possible implementation
template< class T > struct type_identity { using type = T; }; |
Notes
type_identity
can be used to block template argument deduction:
template<class T> void f(T, T); template<class T> void g(T, std::type_identity_t<T>); f(4.2, 0); // error, deduced conflicting types for 'T' g(4.2, 0); // OK, calls g<double>
Example
This section is incomplete Reason: no example |