Future< ResultType > Class Template Reference

Corresponds to std::future. More...

#include <Future.h>

Public Member Functions
	Future ()=default
	Future (const Future &o)=delete
	Future (Future &&)=default
Future &	operator= (Future &&)=default
	~Future ()=default
template<typename T >
PackagedTask< ResultType >	Wrap (T &&func)
	Make the future wait for the result of func. More...
template<typename SfinaeType = ResultType>
std::enable_if_t<!std::is_same_v< SfinaeType, void >, ResultType >	Get ()
	Move the result out of the future, and invalidate the future. More...
bool	IsReady () const
bool	Valid () const
void	Wait ()
void	CancelOrWait ()
	Cancels the task, waiting if the task is currently started. More...

Protected Attributes
std::shared_ptr< SharedState >	m_SharedState

Private Types
using	Status = FutureSharedStateDetail::Status
using	SharedState = FutureSharedStateDetail::SharedState< ResultType >

Static Private Attributes
static constexpr bool	VoidResult = std::is_same_v<ResultType, void>

Friends
template<typename T >
class	PackagedTask

Detailed Description

template<typename ResultType>
class Future< ResultType >

Corresponds to std::future.

Lightweight header / forward declarations for Future.

Unlike std::future, Future can request the cancellation of the task that would produce the result. This makes it more similar to Java's CancellableTask or C#'s Task. The name Future was kept over Task so it would be more familiar to C++ users, but this all should be revised once Concurrency TS wraps up.

Future is not thread-safe. Call it from a single thread or ensure synchronization externally.

The destructor is never blocking. The promise may still be running on destruction. TODO:

• Handle exceptions.

Include this in your header files where possible.

Member Typedef Documentation

SharedState

template<typename ResultType>

using Future< ResultType >::SharedState = FutureSharedStateDetail::SharedState<ResultType>

private

Status

template<typename ResultType>

using Future< ResultType >::Status = FutureSharedStateDetail::Status

private

Constructor & Destructor Documentation

Future() [1/3]

template<typename ResultType>

Future< ResultType >::Future ( )

default

Future() [2/3]

template<typename ResultType>

Future< ResultType >::Future ( const Future< ResultType > &  o )

delete

Future() [3/3]

template<typename ResultType>

Future< ResultType >::Future ( Future< ResultType > &&  )

default

~Future()

template<typename ResultType>

Future< ResultType >::~Future ( )

default

Member Function Documentation

CancelOrWait()

template<typename ResultType>

void Future< ResultType >::CancelOrWait ( )

inline

Cancels the task, waiting if the task is currently started.

Use this function over Cancel() if you need to ensure determinism (i.e. in the simulation).

See also

Cancel.

Get()

template<typename ResultType>

template<typename SfinaeType = ResultType>

std::enable_if_t<!std::is_same_v<SfinaeType, void>, ResultType> Future< ResultType >::Get ( )

inline

Move the result out of the future, and invalidate the future.

If the future is not complete, calls Wait(). If the future is canceled, asserts.

IsReady()

template<typename ResultType>

bool Future< ResultType >::IsReady ( ) const

inline

Returns

true if the shared state is valid and has a result (i.e. Get can be called).

operator=()

template<typename ResultType>

Future& Future< ResultType >::operator= ( Future< ResultType > &&  )

default

Valid()

template<typename ResultType>

bool Future< ResultType >::Valid ( ) const

inline

Returns

true if the future has a shared state and it's not been invalidated, ie. pending, started or done.

Wait()

template<typename ResultType>

void Future< ResultType >::Wait ( )

inline

Wrap()

template<typename ResultType >

template<typename T >

PackagedTask< ResultType > Future< ResultType >::Wrap

(

T &&

func

)

Make the future wait for the result of func.

Friends And Related Function Documentation

PackagedTask

template<typename ResultType>

template<typename T >

friend class PackagedTask

friend

Member Data Documentation

m_SharedState

template<typename ResultType>

std::shared_ptr<SharedState> Future< ResultType >::m_SharedState

protected

VoidResult

template<typename ResultType>

constexpr bool Future< ResultType >::VoidResult = std::is_same_v<ResultType, void>

staticprivate

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

• /zpool0/docker-engine-docs/source/ps/Future.h