23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.8 Logical operations [logical.operations]

The library provides basic function object classes for all of the logical operators in the language ([expr.log.and], [expr.log.or], [expr.unary.op]).

23.14.8.1 Class template logical_­and [logical.operations.and]

template <class T = void> struct logical_and { 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 logical_and<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).

23.14.8.2 Class template logical_­or [logical.operations.or]

template <class T = void> struct logical_or { 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 logical_or<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).

23.14.8.3 Class template logical_­not [logical.operations.not]

template <class T = void> struct logical_not { constexpr bool operator()(const T& x) const; };
constexpr bool operator()(const T& x) const;
Returns: !x.
template <> struct logical_not<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).