Implementation of the C++23 expected class which can contain an error or a success value. More...

#include <expected.hpp>

Public Member Functions
	expected ()=delete
	default ctor is deleted since you have to clearly state if the expected contains a success value or an error value

	expected (const expected &) noexcept=default
	the copy constructor calls the copy constructor of the contained success value or the error value - depending on what is stored in the expected

	expected (expected &&rhs) noexcept
	the move constructor calls the move constructor of the contained success value or the error value - depending on what is stored in the expected

template<typename... Targs>
	expected (in_place_t, Targs &&... args) noexcept
	Creates an expected which is signaling success and perfectly forwards the args to the constructor of ValueType.

template<typename... Targs>
	expected (unexpect_t, Targs &&... args) noexcept
	Creates an expected which is signaling an error and perfectly forwards the args to the constructor of ErrorType.

	~expected () noexcept=default
	calls the destructor of the success value or error value - depending on what is stored in the expected

expected &	operator= (const expected &) noexcept
	calls the copy assignment operator of the contained success value or the error value - depending on what is stored in the expected

expected &	operator= (expected &&rhs) noexcept
	calls the move assignment operator of the contained success value or the error value - depending on what is stored in the expected

	expected (const detail::ok< ValueType > &successValue) noexcept
	constructs an expected which is signaling success and uses the value provided by successValue to copy construct its success value

	expected (detail::ok< ValueType > &&successValue) noexcept
	constructs an expected which is signaling success and uses the value provided by successValue to move construct its success value

	expected (const detail::err< ErrorType > &errorValue) noexcept
	constructs an expected which is signaling an error and stores the error value provided by errorValue

	expected (detail::err< ErrorType > &&errorValue) noexcept
	constructs an expected which is signaling an error and stores the error value provided by errorValue

	operator bool () const noexcept
	returns true if the expected contains a value type and false if it is an error type

bool	has_value () const noexcept
	returns true if the expected contains a value type and false if it is an error type

bool	has_error () const noexcept
	returns true if the expected contains an error otherwise false

ErrorType &	error (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) &noexcept
	returns a lvalue reference to the contained error value, if the expected does not contain an error the error handler is called

const ErrorType &	error (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) const &noexcept
	returns a const lvalue reference to the contained error value, if the expected does not contain an error the error handler is called

ErrorType &&	error (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) &&noexcept
	returns a rvalue reference to the contained error value, if the expected does not contain an error the error handler is called

const ErrorType &&	error (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) const &&noexcept
	returns a const rvalue reference to the contained error value, if the expected does not contain an error the error handler is called

template<typename U = ValueType>
enable_if_non_void_t< U > &	value (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) &noexcept
	returns a lvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

template<typename U = ValueType>
const enable_if_non_void_t< U > &	value (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) const &noexcept
	returns a const lvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

template<typename U = ValueType>
enable_if_non_void_t< U > &&	value (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) &&noexcept
	returns a rvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

template<typename U = ValueType>
const enable_if_non_void_t< U > &&	value (bb::detail::SourceLocation location=bb::detail::SourceLocation::current()) const &&noexcept
	returns a const rvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

template<typename U = ValueType>
enable_if_non_void_t< U > &	operator* () noexcept
	dereferencing operator which returns a reference to the contained success value. if the expected contains an error the error handler is called

template<typename U = ValueType>
const enable_if_non_void_t< U > &	operator* () const noexcept
	dereferencing operator which returns a reference to the contained success value. if the expected contains an error the error handler is called

template<typename U = ValueType>
enable_if_non_void_t< U > *	operator-> () noexcept
	arrow operator which returns the pointer to the contained success value if the expected contains an error the error handler is called

template<typename U = ValueType>
const enable_if_non_void_t< U > *	operator-> () const noexcept
	arrow operator which returns the pointer to the contained success value if the expected contains an error the the error handler is called

	operator expected< void, ErrorType > () const noexcept
	conversion operator to a 'void' value type expected which can be useful if you would like to return only the success of a function

Friends
template<typename T , typename E >
constexpr	bool::iox2::legacy::operator== (const expected< T, E > &, const expected< T, E > &) noexcept

Detailed Description

template<typename ValueType, typename ErrorType>
class iox2::legacy::expected< ValueType, ErrorType >

Implementation of the C++23 expected class which can contain an error or a success value.

Parameters

ValueType	type of the value which can be stored in the expected
ErrorType	type of the error which can be stored in the expected

Definition at line 150 of file expected.hpp.

Constructor & Destructor Documentation

◆ expected() [1/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( )

delete

default ctor is deleted since you have to clearly state if the expected contains a success value or an error value

◆ expected() [2/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( const expected< ValueType, ErrorType > & )

defaultnoexcept

the copy constructor calls the copy constructor of the contained success value or the error value - depending on what is stored in the expected

◆ expected() [3/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( expected< ValueType, ErrorType > && rhs )

noexcept

the move constructor calls the move constructor of the contained success value or the error value - depending on what is stored in the expected

Note: The move c'tor does not explicitly invalidate the moved-from object but relies on the move c'tor of ValueType or ErrorType to correctly invalidate the stored object

◆ expected() [4/9]

template<typename ValueType , typename ErrorType >

template<typename... Targs>

iox2::legacy::expected< ValueType, ErrorType >::expected	(	in_place_t	,
		Targs &&...	args
	)

explicitnoexcept

Creates an expected which is signaling success and perfectly forwards the args to the constructor of ValueType.

Template Parameters

Targs is the template parameter pack for the perfectly forwarded arguments

Parameters

[in]	in_place_t	compile time variable to distinguish between constructors with certain behavior
[in]	args...	arguments which will be forwarded to the 'ValueType' constructor

◆ expected() [5/9]

template<typename ValueType , typename ErrorType >

template<typename... Targs>

iox2::legacy::expected< ValueType, ErrorType >::expected	(	unexpect_t	,
		Targs &&...	args
	)

explicitnoexcept

Creates an expected which is signaling an error and perfectly forwards the args to the constructor of ErrorType.

Template Parameters

Targs is the template parameter pack for the perfectly forwarded arguments

Parameters

[in]	unexpect_t	compile time variable to distinguish between constructors with certain behavior
[in]	args...	arguments which will be forwarded to the 'ErrorType' constructor

◆ ~expected()

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::~expected ( )

defaultnoexcept

calls the destructor of the success value or error value - depending on what is stored in the expected

◆ expected() [6/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( const detail::ok< ValueType > & successValue )

noexcept

constructs an expected which is signaling success and uses the value provided by successValue to copy construct its success value

Parameters

[in] successValue value which will be stored in the expected

◆ expected() [7/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( detail::ok< ValueType > && successValue )

noexcept

constructs an expected which is signaling success and uses the value provided by successValue to move construct its success value

Parameters

[in] successValue value which will be moved into the expected

◆ expected() [8/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( const detail::err< ErrorType > & errorValue )

noexcept

constructs an expected which is signaling an error and stores the error value provided by errorValue

Parameters

[in] errorValue error value which will be stored in the expected

◆ expected() [9/9]

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::expected ( detail::err< ErrorType > && errorValue )

noexcept

constructs an expected which is signaling an error and stores the error value provided by errorValue

Parameters

[in] errorValue error value which will be moved into the expected

Member Function Documentation

◆ error() [1/4]

template<typename ValueType , typename ErrorType >

ErrorType && iox2::legacy::expected< ValueType, ErrorType >::error ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) &&

noexcept

returns a rvalue reference to the contained error value, if the expected does not contain an error the error handler is called

Returns: rvalue reference to the internally contained error

◆ error() [2/4]

template<typename ValueType , typename ErrorType >

ErrorType & iox2::legacy::expected< ValueType, ErrorType >::error ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) &

noexcept

returns a lvalue reference to the contained error value, if the expected does not contain an error the error handler is called

Returns: lvalue reference to the internally contained error

Referenced by iox2::bb::stl::Expected< T, E >::error(), and iox2::bb::stl::Expected< T, E >::error().

◆ error() [3/4]

template<typename ValueType , typename ErrorType >

const ErrorType && iox2::legacy::expected< ValueType, ErrorType >::error ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) const &&

noexcept

returns a const rvalue reference to the contained error value, if the expected does not contain an error the error handler is called

Returns: const rvalue reference to the internally contained error

◆ error() [4/4]

template<typename ValueType , typename ErrorType >

const ErrorType & iox2::legacy::expected< ValueType, ErrorType >::error ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) const &

noexcept

returns a const lvalue reference to the contained error value, if the expected does not contain an error the error handler is called

Returns: const lvalue reference to the internally contained error

◆ has_error()

template<typename ValueType , typename ErrorType >

bool iox2::legacy::expected< ValueType, ErrorType >::has_error ( ) const

noexcept

returns true if the expected contains an error otherwise false

Returns: bool which contains true if the expected contains an error

◆ has_value()

template<typename ValueType , typename ErrorType >

bool iox2::legacy::expected< ValueType, ErrorType >::has_value ( ) const

noexcept

returns true if the expected contains a value type and false if it is an error type

Returns: bool which contains true if the expected contains a value type and false if it is an error type

Referenced by iox2::bb::stl::Expected< T, E >::has_value().

◆ operator bool()

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::operator bool ( ) const

explicitnoexcept

returns true if the expected contains a value type and false if it is an error type

Returns: bool which contains true if the expected contains a value type and false if it is an error type

◆ operator expected< void, ErrorType >()

template<typename ValueType , typename ErrorType >

iox2::legacy::expected< ValueType, ErrorType >::operator expected< void, ErrorType > ( ) const

noexcept

conversion operator to a 'void' value type expected which can be useful if you would like to return only the success of a function

Returns: converts an expected which can contain a value and an error to an expected which contains only an error
expected<int, int> someErrorProneFunction(){}

expected<void, int> isItSuccessful() {

return someErrorProneFunction();

}

iox2::legacy::expected
Implementation of the C++23 expected class which can contain an error or a success value.
Definition expected.hpp:150

iox2::legacy::always_false_v
constexpr bool always_false_v
Helper value to bind a static_assert to a type.
Definition type_traits.hpp:48

◆ operator*() [1/2]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

const enable_if_non_void_t & iox2::legacy::expected< ValueType, ErrorType >::operator* ( ) const

noexcept

dereferencing operator which returns a reference to the contained success value. if the expected contains an error the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: const reference to the contained value

Note: this only works for non void ValueTypes
expected<int, float> frodo(ok(45));

*frodo += 12;

IOX2_LOG(Info, *frodo); // prints 57

IOX2_LOG
#define IOX2_LOG(level, msg_stream)
Macro for logging.
Definition logging.hpp:63

iox2::legacy::ok
detail::ok< void > ok()
convenience function to create an 'expected' with a 'void' value type

iox2::LogLevel::Info
@ Info

◆ operator*() [2/2]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

enable_if_non_void_t & iox2::legacy::expected< ValueType, ErrorType >::operator* ( )

noexcept

dereferencing operator which returns a reference to the contained success value. if the expected contains an error the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: reference to the contained value

Note: this only works for non void ValueTypes
expected<int, float> frodo(ok(45));

*frodo += 12;

IOX2_LOG(Info, *frodo); // prints 57

◆ operator->() [1/2]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

const enable_if_non_void_t * iox2::legacy::expected< ValueType, ErrorType >::operator-> ( ) const

noexcept

arrow operator which returns the pointer to the contained success value if the expected contains an error the the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: pointer of type const ValueType to the contained value

Note: this only works for non void ValueTypes
expected<std::vector<int>, int> holyPiotr(ok<std::vector<int>>({1,2,3}));

holyPiotr->push_back(4);

◆ operator->() [2/2]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

enable_if_non_void_t * iox2::legacy::expected< ValueType, ErrorType >::operator-> ( )

noexcept

arrow operator which returns the pointer to the contained success value if the expected contains an error the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: pointer of type ValueType to the contained value

Note: this only works for non void ValueTypes
expected<std::vector<int>, int> holyPiotr(ok<std::vector<int>>({1,2,3}));

holyPiotr->push_back(4);

◆ operator=() [1/2]

template<typename ValueType , typename ErrorType >

expected & iox2::legacy::expected< ValueType, ErrorType >::operator= ( const expected< ValueType, ErrorType > & )

noexcept

calls the copy assignment operator of the contained success value or the error value - depending on what is stored in the expected

◆ operator=() [2/2]

template<typename ValueType , typename ErrorType >

expected & iox2::legacy::expected< ValueType, ErrorType >::operator= ( expected< ValueType, ErrorType > && rhs )

noexcept

calls the move assignment operator of the contained success value or the error value - depending on what is stored in the expected

Note: The move assignment operator does not explicitly invalidate the moved-from object but relies on the move assignment operator of ValueType or ErrorType to correctly invalidate the stored object

◆ value() [1/4]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

enable_if_non_void_t && iox2::legacy::expected< ValueType, ErrorType >::value ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) &&

noexcept

returns a rvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: rvalue reference to the internally contained value

◆ value() [2/4]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

enable_if_non_void_t & iox2::legacy::expected< ValueType, ErrorType >::value ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) &

noexcept

returns a lvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: lvalue reference to the internally contained value

Note: this only works for non void ValueTypes

Referenced by iox2::bb::stl::Expected< T, E >::value(), and iox2::bb::stl::Expected< T, E >::value().

◆ value() [3/4]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

const enable_if_non_void_t && iox2::legacy::expected< ValueType, ErrorType >::value ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) const &&

noexcept

returns a const rvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: const rvalue reference to the internally contained value

◆ value() [4/4]

template<typename ValueType , typename ErrorType >

template<typename U = ValueType>

const enable_if_non_void_t & iox2::legacy::expected< ValueType, ErrorType >::value ( bb::detail::SourceLocation location = bb::detail::SourceLocation::current() ) const &

noexcept

returns a const lvalue reference to the contained success value, if the expected does not contain a success value the error handler is called

Template Parameters

U	helper template parameter for SFINEA

Returns: const lvalue reference to the internally contained value

Note: this only works for non void ValueTypes

Friends And Related Symbol Documentation

◆ bool::iox2::legacy::operator==

template<typename ValueType , typename ErrorType >

template<typename T , typename E >

constexpr bool::iox2::legacy::operator==	(	const expected< T, E > &	,
		const expected< T, E > &
	)

friend

The documentation for this class was generated from the following file:

iox2/legacy/expected.hpp

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ expected() [1/9]

◆ expected() [2/9]

◆ expected() [3/9]

◆ expected() [4/9]

◆ expected() [5/9]

◆ ~expected()

◆ expected() [6/9]

◆ expected() [7/9]

◆ expected() [8/9]

◆ expected() [9/9]

Member Function Documentation

◆ error() [1/4]

◆ error() [2/4]

◆ error() [3/4]

◆ error() [4/4]

◆ has_error()

◆ has_value()

◆ operator bool()

◆ operator expected< void, ErrorType >()

◆ operator*() [1/2]

◆ operator*() [2/2]

◆ operator->() [1/2]

◆ operator->() [2/2]

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ value() [1/4]

◆ value() [2/4]

◆ value() [3/4]

◆ value() [4/4]

Friends And Related Symbol Documentation

◆ bool::iox2::legacy::operator==