std::expected<T,E>::expected
From cppreference.com
Main template |
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constexpr expected(); |
(1) | (since C++23) |
constexpr expected( const expected& other ); |
(2) | (since C++23) |
constexpr expected( expected&& other ) noexcept(/* see below */); |
(3) | (since C++23) |
template< class U, class G > constexpr expected( const expected<U, G>& other ); |
(4) | (since C++23) (conditionally explicit) |
template< class U, class G > constexpr expected( expected<U, G>&& other ); |
(5) | (since C++23) (conditionally explicit) |
template< class U = std::remove_cv_t<T> > constexpr explicit(!std::is_convertible_v<U, T>) expected( U&& v ); |
(6) | (since C++23) |
template< class G > constexpr explicit(!std::is_convertible_v<const G&, E>) |
(7) | (since C++23) |
template< class G > constexpr explicit(!std::is_convertible_v<G, E>) |
(8) | (since C++23) |
template< class... Args > constexpr explicit expected( std::in_place_t, Args&&... args ); |
(9) | (since C++23) |
template< class U, class... Args > constexpr explicit |
(10) | (since C++23) |
template< class... Args > constexpr explicit expected( std::unexpect_t, Args&&... args ); |
(11) | (since C++23) |
template< class U, class... Args > constexpr explicit |
(12) | (since C++23) |
void partial specialization |
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constexpr expected(); |
(13) | (since C++23) |
constexpr expected( const expected& other ); |
(14) | (since C++23) |
constexpr expected( expected&& other ) noexcept(std::is_nothrow_move_constructible_v<E>); |
(15) | (since C++23) |
template< class U, class G > constexpr explicit(!std::is_convertible_v<const G&, E>) |
(16) | (since C++23) |
template< class U, class G > constexpr explicit(!std::is_convertible_v<G, E>) |
(17) | (since C++23) |
template< class G > constexpr explicit(!std::is_convertible_v<const G&, E>) |
(18) | (since C++23) |
template< class G > constexpr explicit(!std::is_convertible_v<G, E>) |
(19) | (since C++23) |
constexpr explicit expected( std::in_place_t ); |
(20) | (since C++23) |
template< class... Args > constexpr explicit expected( std::unexpect_t, Args&&... args ); |
(21) | (since C++23) |
template< class U, class... Args > constexpr explicit |
(22) | (since C++23) |
Constructs a new expected
object.
Contents |
[edit] Parameters
other | - | another expected object whose contained value is copied
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e | - | std::unexpected object whose contained value is copied
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v | - | value with which to initialize the contained value |
args | - | arguments with which to initialize the contained value |
il | - | initializer list with which to initialize the contained value |
[edit] Effects
[edit] Primary template constructors
Overload | Initialization method |
Initializer for... | has_value() after construction | |
---|---|---|---|---|
the expected value | the unexpected value | |||
(1) | Value | (empty) | - | true |
(2) | Direct (non-list) |
*other | other.error() | other.has_value()
|
(3) | std::move(*other) | std::move(other.error()) | ||
(4) | std::forward<const U&> (*other) |
std::forward<const G&> (other.error()) | ||
(5) | std::forward<U>(*other) | std::forward<G> (other.error()) | ||
(6) | std::forward<U>(v) | - | true | |
(7) | - | std::forward<const G&> (e.error()) |
false | |
(8) | std::forward<G>(e.error()) | |||
(9) | std::forward<Args>(args)... | - | true | |
(10) | il, std::forward<Args>(args)... | |||
(11) | - | std::forward<Args>(args)... | false | |
(12) | il, std::forward<Args>(args)... |
[edit] void partial specialization constructors
Overload | Initialization method | Initializer for the unexpected value | has_value() after construction
|
---|---|---|---|
(13) | N/A | - | true |
(14) | Direct (non-list) | rhs.error() | other.has_value()
|
(15) | std::move(rhs.error) | ||
(16) | std::forward<const G&>(rhs.error()) | ||
(17) | std::forward<G>(rhs.error()) | ||
(18) | std::forward<const G&>(e.error()) | false | |
(19) | std::forward<G>(e.error()) | ||
(20) | N/A | - | true |
(21) | Direct (non-list) | std::forward<Args>(args)... | false |
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