trait is_same for arbitrary many types

Asked Dec 06 '22 at 14:07

Active Dec 06 '22 at 14:12

Viewed 77 times

The type_traits library offers the possibility to check if two type are the same with is_same.

How can one generalize to an arbitrary long list of types? Something declared as

template <class... U>
struct is_same_many;

with a field value such that value = true if all Us are the same, and false otherwise.

asked Dec 06 '22 at 14:07

francesco

See [How to make a variadic is_same?](https://stackoverflow.com/questions/17032310/how-to-make-a-variadic-is-same). – Jason Dec 06 '22 at 14:10
With C++17 you can use fold expressions: `template constexpr bool is_same_v = (std::is_same_v && ...);` – joergbrech Dec 06 '22 at 14:10
https://godbolt.org/z/f11djvon7 – Marek R Dec 06 '22 at 14:12
@joergbrech Make that an answer. – lorro Dec 06 '22 at 14:13
2

@lorro It is already an [answer](https://stackoverflow.com/a/52328061/12002570) – Jason Dec 06 '22 at 14:15
Yes, better mark this a duplicate – joergbrech Dec 06 '22 at 14:22

0 Answers0