19 General utilities library [utilities]

19.14 Function objects [function.objects]

19.14.10 Class identity [func.identity]

struct identity { template<class T> constexpr T&& operator()(T&& t) const noexcept; using is_transparent = unspecified; }; template<class T> constexpr T&& operator()(T&& t) const noexcept;
Effects: Equivalent to: return std::forward<T>(t);