23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.7 Comparisons [comparisons]

23.14.7.2 Class template not_­equal_­to [comparisons.not_equal_to]

template <class T = void> struct not_equal_to { constexpr bool operator()(const T& x, const T& y) const; }; constexpr bool operator()(const T& x, const T& y) const;
Returns: x != y.
template <> struct not_equal_to<void> { template <class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) != std::forward<U>(u)); using is_transparent = unspecified; };
template <class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) != std::forward<U>(u));
Returns: std​::​forward<T>(t) != std​::​forward<U>(u).