[expected.void.cons] (original) (raw)

22 General utilities library [utilities]

22.8 Expected objects [expected]

22.8.7 Partial specialization of expected for void types [expected.void]

22.8.7.2 Constructors [expected.void.cons]

constexpr expected() noexcept;

Postconditions: has_value() is true.

constexpr expected(const expected& rhs);

Effects: If rhs.has_value() is false, direct-non-list-initializes unex with rhs.error().

Postconditions: rhs.has_value() == this->has_value().

Throws: Any exception thrown by the initialization of unex.

Remarks: This constructor is defined as deleted unless is_copy_constructible_v<E> is true.

This constructor is trivial if is_trivially_copy_constructible_v<E> is true.

constexpr expected(expected&& rhs) noexcept(is_nothrow_move_constructible_v<E>);

Constraints: is_move_constructible_v<E> is true.

Effects: If rhs.has_value() is false, direct-non-list-initializes unex with std​::​move(rhs.error()).

Postconditions: rhs.has_value() is unchanged;rhs.has_value() == this->has_value() is true.

Throws: Any exception thrown by the initialization of unex.

Remarks: This constructor is trivial if is_trivially_move_constructible_v<E> is true.

template<class U, class G> constexpr explicit(!is_convertible_v<const G&, E>) expected(const expected<U, G>& rhs);template<class U, class G> constexpr explicit(!is_convertible_v<G, E>) expected(expected<U, G>&& rhs);

Let GF be const G& for the first overload andG for the second overload.

Constraints:

• is_void_v<U> is true; and
• is_constructible_v<E, GF> is true; and
• is_constructible_v<unexpected<E>, expected<U, G>&>is false; and
• is_constructible_v<unexpected<E>, expected<U, G>>is false; and
• is_constructible_v<unexpected<E>, const expected<U, G>&>is false; and
• is_constructible_v<unexpected<E>, const expected<U, G>>is false.

Effects: If rhs.has_value() is false, direct-non-list-initializes _unex_with std​::​forward<GF>(rhs.error()).

Postconditions: rhs.has_value() is unchanged;rhs.has_value() == this->has_value() is true.

Throws: Any exception thrown by the initialization of unex.

template<class G> constexpr explicit(!is_convertible_v<const G&, E>) expected(const unexpected<G>& e);template<class G> constexpr explicit(!is_convertible_v<G, E>) expected(unexpected<G>&& e);

Let GF be const G& for the first overload andG for the second overload.

Constraints: is_constructible_v<E, GF> is true.

Effects: Direct-non-list-initializes _unex_with std​::​forward<GF>(e.error()).

Postconditions: has_value() is false.

Throws: Any exception thrown by the initialization of unex.

constexpr explicit expected(in_place_t) noexcept;

Postconditions: has_value() is true.

template<class... Args> constexpr explicit expected(unexpect_t, Args&&... args);

Constraints: is_constructible_v<E, Args...> is true.

Effects: Direct-non-list-initializes _unex_with std​::​forward<Args>(args)....

Postconditions: has_value() is false.

Throws: Any exception thrown by the initialization of unex.

template<class U, class... Args> constexpr explicit expected(unexpect_t, initializer_list<U> il, Args&&... args);

Constraints: is_constructible_v<E, initializer_list<U>&, Args...> is true.

Effects: Direct-non-list-initializes _unex_with il, std​::​forward<Args>(args)....

Postconditions: has_value() is false.

Throws: Any exception thrown by the initialization of unex.