[expected.un.general] (original) (raw)

Subclause [expected.unexpected] describes the class template unexpectedthat represents unexpected objects stored in expected objects.

namespace std { template<class E> class unexpected { public: constexpr unexpected(const unexpected&) = default;constexpr unexpected(unexpected&&) = default;template<class Err = E> constexpr explicit unexpected(Err&&);template<class... Args> constexpr explicit unexpected(in_place_t, Args&&...);template<class U, class... Args> constexpr explicit unexpected(in_place_t, initializer_list<U>, Args&&...);constexpr unexpected& operator=(const unexpected&) = default;constexpr unexpected& operator=(unexpected&&) = default;constexpr const E& error() const & noexcept;constexpr E& error() & noexcept;constexpr const E&& error() const && noexcept;constexpr E&& error() && noexcept;constexpr void swap(unexpected& other) noexcept(see below);template<class E2> friend constexpr bool operator==(const unexpected&, const unexpected<E2>&);friend constexpr void swap(unexpected& x, unexpected& y) noexcept(noexcept(x.swap(y)));private: E unex; };template<class E> unexpected(E) -> unexpected<E>;}

A program that instantiates the definition of unexpected for a non-object type, an array type, a specialization of unexpected, or a cv-qualified type is ill-formed.