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]).
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).
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).
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).