cf::unexpected¶

Wrapper type for constructing expected objects in error state. More...

#include <expected.hpp>

Public Functions¶

	Name
	unexpected() =delete Deleted default constructor.
template <typenameErr =E,typename =std::enable_if_t<!std::is_same_v, unexpected> && std::is_constructible_v>> constexpr	unexpected(Err && e) Constructs unexpected from an error value.
template <typename... Args,typename =std::enable_if_t>> constexpr	unexpected(std::in_place_t , Args &&... args) Constructs unexpected in-place with arguments.
template <typenameU ,typename... Args,typename =std::enable_if_t&, Args...>>> constexpr	unexpected(std::in_place_t , std::initializer_list< U > il, Args &&... args) Constructs unexpected in-place with initializer list.
constexpr const E &	error() const Returns const reference to the error.
constexpr E &	error() Returns reference to the error.
constexpr const E &&	error() const Returns const rvalue reference to the error.
constexpr E &&	error() Returns rvalue reference to the error.
void	swap(unexpected & other) Swaps the error with another unexpected.

Friends¶

	Name
constexpr bool	operator==(const unexpected & a, const unexpected< E2 > & b) Compares two unexpected objects for equality.

Detailed Description¶

template <typenameE >
class cf::unexpected;

Wrapper type for constructing expected objects in error state.

Template Parameters:

E Error type to wrap.

Public Functions Documentation¶

function unexpected¶

unexpected() =delete

Deleted default constructor.

function unexpected¶

template <typenameErr  =E,
typename  =std::enable_if_t<!std::is_same_v<std::decay_t<Err>, unexpected> &&                                          std::is_constructible_v<E, Err>>>
inline explicit constexpr unexpected(
    Err && e
)

Constructs unexpected from an error value.

Parameters:

e Error value to wrap.

Template Parameters:

Err Forwarded error type.

function unexpected¶

template <typename... Args,
typename  =std::enable_if_t<std::is_constructible_v<E, Args...>>>
inline explicit constexpr unexpected(
    std::in_place_t ,
    Args &&... args
)

Constructs unexpected in-place with arguments.

Parameters:

args Arguments to forward to E constructor.

Template Parameters:

Args Constructor argument types.

function unexpected¶

template <typenameU ,
typename... Args,
typename  =std::enable_if_t<std::is_constructible_v<E, std::initializer_list<U>&, Args...>>>
inline explicit constexpr unexpected(
    std::in_place_t ,
    std::initializer_list< U > il,
    Args &&... args
)

Constructs unexpected in-place with initializer list.

Parameters:

il Initializer list.
args Additional arguments.

Template Parameters:

U Element type of initializer list.
Args Constructor argument types.

function error¶

inline constexprconstE & error() const

Returns const reference to the error.

Exceptions:

None.

Return: Const reference to the error.

function error¶

inline constexprE & error()

Returns reference to the error.

Exceptions:

None.

Return: Reference to the error.

function error¶

inline constexprconstE && error() const

Returns const rvalue reference to the error.

Exceptions:

None.

Return: Const rvalue reference to the error.

function error¶

inline constexprE && error()

Returns rvalue reference to the error.

Exceptions:

None.

Return: Rvalue reference to the error.

function swap¶

inline void swap(
    unexpected & other
)

Swaps the error with another unexpected.

Parameters:

other Other unexpected to swap with.

Exceptions:

None if E is nothrow swappable.

Since: 0.1

Note: None.

Warning: None.

Friends¶

friend operator==¶

friend constexprbool operator==(
    constunexpected & a,

    constunexpected< E2 > & b
);

Compares two unexpected objects for equality.

Parameters:

a First unexpected.
b Second unexpected.

Exceptions:

None.

Template Parameters:

E2 Error type of the other unexpected.

Return: true if errors are equal, false otherwise.

Updated on 2026-03-09 at 10:14:00 +0000