23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.6 Arithmetic operations [arithmetic.operations]

23.14.6.2 Class template minus [arithmetic.operations.minus]

template<class T = void> struct minus { constexpr T operator()(const T& x, const T& y) const; }; constexpr T operator()(const T& x, const T& y) const;
Returns: x - y.
template<> struct minus<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).