ROOT::Experimental::RResult< T > Class Template Reference

template<typename T>
class ROOT::Experimental::RResult< T >

The class is used as a return type for operations that can fail; wraps a value of type T or an RError.

RResult enforces checking whether it contains a valid value or an error state. If the RResult leaves the scope unchecked, it will throw an exception (due to ~RResultBase).

Definition at line 195 of file RError.hxx.

Public Member Functions
	RResult (const RResult &other)=delete
	RResult (const T &value)
	RResult (RError &&error)
	RResult (RResult &&other)=default
	RResult (T &&value)
	~RResult ()=default
RResult &	Forward (RError::RLocation &&sourceLocation)
	Used by R__FORWARD_RESULT in order to keep track of the stack trace in case of errors.
const T &	Inspect ()
	If the operation was successful, returns a const reference to the inner type.
	operator bool ()
RResult &	operator= (const RResult &other)=delete
RResult &	operator= (RResult &&other)=default
T	Unwrap ()
	If the operation was successful, returns the inner type by value.
Public Member Functions inherited from ROOT::Experimental::Internal::RResultBase
	RResultBase (const RResultBase &other)=delete
	RResultBase (RResultBase &&other)=default
	~RResultBase () noexcept(false)
RError *	GetError ()
void *	operator new (std::size_t size)=delete
void *	operator new (std::size_t, void *)=delete
void *	operator new[] (std::size_t)=delete
void *	operator new[] (std::size_t, void *)=delete
RResultBase &	operator= (const RResultBase &other)=delete
RResultBase &	operator= (RResultBase &&other)=default
void	Throw ()
	Throws an RException with fError.

Private Member Functions
void	ThrowOnError ()

Private Attributes
T	fValue
	The result value in case of successful execution.

Additional Inherited Members
Static Public Member Functions inherited from ROOT::Experimental::Internal::RResultBase
static RError	ForwardError (RResultBase &&result, RError::RLocation &&sourceLocation)
	Used by R__FORWARD_ERROR in order to keep track of the stack trace.
Protected Member Functions inherited from ROOT::Experimental::Internal::RResultBase
	RResultBase ()=default
	RResultBase (RError &&error)
bool	Check ()
	Used by the RResult<T> bool operator.
Protected Attributes inherited from ROOT::Experimental::Internal::RResultBase
std::unique_ptr< RError >	fError
	This is the nullptr for an RResult representing success.
bool	fIsChecked {false}
	Switches to true once the user of an RResult object checks the object status.

#include <ROOT/RError.hxx>

Inheritance diagram for ROOT::Experimental::RResult< T >:

Constructor & Destructor Documentation

RResult() [1/5]

template<typename T >

ROOT::Experimental::RResult< T >::RResult ( const T &  value )

inline

Definition at line 215 of file RError.hxx.

RResult() [2/5]

template<typename T >

ROOT::Experimental::RResult< T >::RResult ( T &&  value )

inline

Definition at line 216 of file RError.hxx.

RResult() [3/5]

template<typename T >

ROOT::Experimental::RResult< T >::RResult ( RError &&  error )

inline

Definition at line 217 of file RError.hxx.

RResult() [4/5]

template<typename T >

ROOT::Experimental::RResult< T >::RResult ( const RResult< T > &  other )

delete

RResult() [5/5]

template<typename T >

ROOT::Experimental::RResult< T >::RResult ( RResult< T > &&  other )

default

~RResult()

template<typename T >

ROOT::Experimental::RResult< T >::~RResult ( )

default

Member Function Documentation

Forward()

template<typename T >

RResult & ROOT::Experimental::RResult< T >::Forward ( RError::RLocation &&  sourceLocation )

inline

Used by R__FORWARD_RESULT in order to keep track of the stack trace in case of errors.

Definition at line 227 of file RError.hxx.

Inspect()

template<typename T >

const T & ROOT::Experimental::RResult< T >::Inspect ( )

inline

If the operation was successful, returns a const reference to the inner type.

If there was an error, Inspect() instead throws an exception.

Definition at line 235 of file RError.hxx.

operator bool()

template<typename T >

ROOT::Experimental::RResult< T >::operator bool ( )

inlineexplicit

Definition at line 252 of file RError.hxx.

operator=() [1/2]

template<typename T >

RResult & ROOT::Experimental::RResult< T >::operator= ( const RResult< T > &  other )

delete

operator=() [2/2]

template<typename T >

RResult & ROOT::Experimental::RResult< T >::operator= ( RResult< T > &&  other )

default

ThrowOnError()

template<typename T >

void ROOT::Experimental::RResult< T >::ThrowOnError ( )

inlineprivate

Definition at line 201 of file RError.hxx.

Unwrap()

template<typename T >

T ROOT::Experimental::RResult< T >::Unwrap ( )

inline

If the operation was successful, returns the inner type by value.

For move-only types, Unwrap can only be called once, as it yields ownership of the inner value to the caller using std::move, potentially leaving the RResult in an unspecified state.

If there was an error, Unwrap() instead throws an exception.

Definition at line 247 of file RError.hxx.

Member Data Documentation

fValue

template<typename T >

T ROOT::Experimental::RResult< T >::fValue

private

The result value in case of successful execution.

Definition at line 198 of file RError.hxx.