cvw::expected<void, E>

Specialization of expected for void value type. More...

#include <expected.hpp>

Public Types

	Name
using void	value_type Value type alias.
using E	error_type Error type alias.
using unexpected<E>	unexpected_type Unexpected type alias.

Public Functions

	Name
constexpr	expected() Default constructor. Creates expected in success state.
	expected(constexpected & o) Copy constructor.
	expected(expected && o) Move constructor.
template <typenameG =E&gt; constexpr	expected(constunexpected<G> & u) Constructor from unexpected.
template <typenameG =E&gt; constexpr	expected(unexpected<G> && u) Constructor from unexpected rvalue.
constexpr	expected(std::in_place_t ) In-place constructor for success state.
template <typename... Args&gt; constexpr	expected(unexpect_t , Args &&... args) Constructor for in-place error construction.
	~expected() Destructor.
expected &	operator=(constexpected & o) Copy assignment operator.
constexprbool	has_value() const Checks if the expected is in success state.
constexpr	operator bool() const Boolean conversion operator.
constexprvoid	value() const Returns void if in success state.
constexprE &	error() Returns the contained error.
constexprconstE &	error() const Returns the contained error (const lvalue).
constexprE &&	error() Returns the contained error (rvalue).
constexprconstE &&	error() const Returns the contained error (const rvalue).
template <typenameF &gt; auto	and_then(F && f) Monadic operation: chains if in success state.
template <typenameF &gt; auto	and_then(F && f) Monadic operation: chains if in success state (rvalue).
template <typenameF &gt; auto	transform(F && f) Monadic operation: transforms the success state.
template <typenameF &gt; auto	transform(F && f) Monadic operation: transforms the success state (rvalue).

Detailed Description

template <typenameE>
class cvw::expected<void, E>;

Specialization of expected for void value type.

Template Parameters:

• E Error type.

This specialization represents operations that may fail but do not produce a value on success.

Public Types Documentation

using value_type

using cvw::expected<void, E>::value_type =  void;

Value type alias.

using error_type

using cvw::expected<void, E>::error_type =  E;

Error type alias.

using unexpected_type

using cvw::expected<void, E>::unexpected_type =  unexpected<E>;

Unexpected type alias.

Public Functions Documentation

function expected

inline constexpr expected()

Default constructor. Creates expected in success state.

Exceptions:

• None.

function expected

inline expected(
    constexpected & o
)

Copy constructor.

Parameters:

• o Expected to copy from.

Exceptions:

• May throw if E copy constructor throws.

function expected

inline expected(
    expected && o
)

Move constructor.

Parameters:

• o Expected to move from.

Exceptions:

• May throw if E move constructor throws.

function expected

template <typenameG  =E>
inline constexpr expected(
    constunexpected<G> & u
)

Constructor from unexpected.

Parameters:

• u Unexpected value containing error.

Exceptions:

• May throw if E constructor throws.

Template Parameters:

• G Forwarded error type.

function expected

template <typenameG  =E>
inline constexpr expected(
    unexpected<G> && u
)

Constructor from unexpected rvalue.

Parameters:

• u Unexpected value containing error.

Exceptions:

• May throw if E constructor throws.

Template Parameters:

• G Forwarded error type.

function expected

inline explicit constexpr expected(
    std::in_place_t 
)

In-place constructor for success state.

Exceptions:

• None.

function expected

template <typename... Args>
inline explicit constexpr expected(
    unexpect_t ,
    Args &&... args
)

Constructor for in-place error construction.

Parameters:

• args Arguments to forward to E constructor.

Exceptions:

• May throw if E constructor throws.

Template Parameters:

• Args Constructor argument types.

function ~expected

inline ~expected()

Destructor.

Exceptions:

• None.

function operator=

inline expected & operator=(
    constexpected & o
)

Copy assignment operator.

Parameters:

• o Expected to copy from.

Exceptions:

• May throw if E assignment or construction throws.

Return: Reference to this expected.

function has_value

inline constexprbool has_value() const

Checks if the expected is in success state.

Exceptions:

• None.

Return: true if in success state, false if in error state.

function operator bool

inline explicit constexpr operator bool() const

Boolean conversion operator.

Exceptions:

• None.

Return: true if in success state, false if in error state.

function value

inline constexprvoid value() const

Returns void if in success state.

Exceptions:

• bad_expected_access if in error state.

Warning: Throws bad_expected_access if this expected contains an error.

function error

inline constexprE & error()

Returns the contained error.

Exceptions:

• None.

Return: Reference to the contained error.

Warning: The error is only valid if has_value() returns false.

function error

inline constexprconstE & error() const

Returns the contained error (const lvalue).

Exceptions:

• None.

Return: Const reference to the contained error.

Warning: The error is only valid if has_value() returns false.

function error

inline constexprE && error()

Returns the contained error (rvalue).

Exceptions:

• None.

Return: Rvalue reference to the contained error.

Warning: The error is only valid if has_value() returns false.

function error

inline constexprconstE && error() const

Returns the contained error (const rvalue).

Exceptions:

• None.

Return: Const rvalue reference to the contained error.

Warning: The error is only valid if has_value() returns false.

function and_then

template <typenameF>
inline auto and_then(
    F && f
)

Monadic operation: chains if in success state.

Parameters:

• f Function to call if in success state.

Exceptions:

• None.

Template Parameters:

• F Callable type.

Return: Result of f() or error.

function and_then

template <typenameF>
inline auto and_then(
    F && f
)

Monadic operation: chains if in success state (rvalue).

Parameters:

• f Function to call if in success state.

Exceptions:

• None.

Template Parameters:

• F Callable type.

Return: Result of f() or error.

function transform

template <typenameF>
inline auto transform(
    F && f
)

Monadic operation: transforms the success state.

Parameters:

• f Function to apply.

Exceptions:

• None.

Template Parameters:

• F Callable type.

Return: expected with transformed value or error.

function transform

template <typenameF>
inline auto transform(
    F && f
)

Monadic operation: transforms the success state (rvalue).

Parameters:

• f Function to apply.

Exceptions:

• None.

Template Parameters:

• F Callable type.

Return: expected with transformed value or error.

---

Updated on 2026-05-17 at 13:22:38 +0000