23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.6 Arithmetic operations [arithmetic.operations]

23.14.6.6 Class template negate [arithmetic.operations.negate]

template <class T = void> struct negate { constexpr T operator()(const T& x) const; }; constexpr T operator()(const T& x) const;
Returns: -x.
template <> struct negate<void> { template <class T> constexpr auto operator()(T&& t) const -> decltype(-std::forward<T>(t)); using is_transparent = unspecified; }; template <class T> constexpr auto operator()(T&& t) const -> decltype(-std::forward<T>(t));
Returns: -std​::​forward<T>(t).