std::expected<T,E>::error_or

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std::expected
template < class G = E >
constexpr E error_or( G&& default_value ) const & ;
(1) (since C++23)
template < class G = E >
constexpr E error_or( G&& default_value ) && ;
(2) (since C++23)

Returns the unexpected value if it exists, otherwise returns default_value.

1) If std::is_copy_constructible_v<E> or std::is_convertible_v<G, E> is false
2) If std::is_move_constructible_v<E> or std::is_convertible_v<G, E> is false

Parameters

default_value - the value to use in case *this does not contain an unexpected value
Type requirements

Return value

1) has_value( ) ? std::forward <G> (default_value) : error( )
2) has_value( ) ? std::forward <G> (default_value) : std:: move (error( ) )

Example

This section is incomplete
Reason: no example

See also

 returns the unexpected value
(public member function)
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