std::relation

< cpp‎ | concepts

Defined in header `<concepts>`
template <class R, class T, class U> concept relation = std::predicate<R, T, T> && std::predicate<R, U, U> && std::predicate<R, T, U> && std::predicate<R, U, T>;	(1)	(since C++20)

The concept relation<R, T, U> specifies that R defines a binary relation over the set of expressions whose type and value category are those encoded by either T or U.