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description Learn more about: completion_future Class
title completion_future Class
ms.date 11/04/2016
f1_keywords
completion_future
AMPRT/completion_future
AMPRT/Concurrency::completion_future::completion_future
AMPRT/Concurrency::completion_future::get
AMPRT/Concurrency::completion_future::then
AMPRT/Concurrency::completion_future::to_task
AMPRT/Concurrency::completion_future::valid
AMPRT/Concurrency::completion_future::wait
AMPRT/Concurrency::completion_future::wait_for
AMPRT/Concurrency::completion_future::wait_until
ms.assetid 1303c62e-546d-4b02-a578-251ed3fc0b6b

completion_future Class

Represents a future corresponding to a C++ AMP asynchronous operation.

Syntax

class completion_future;

Members

Public Constructors

Name Description
completion_future Constructor Initializes a new instance of the completion_future class.
~completion_future Destructor Destroys the completion_future object.

Public Methods

Name Description
get Waits until the associated asynchronous operation completes.
then Chains a callback function object to the completion_future object to be executed when the associated asynchronous operation finishes execution.
to_task Returns a task object corresponding to the associated asynchronous operation.
valid Gets a Boolean value that indicates whether the object is associated with an asynchronous operation.
wait Blocks until the associated asynchronous operation completes.
wait_for Blocks until the associated asynchronous operation completes or the time specified by _Rel_time has elapsed.
wait_until Blocks until the associated asynchronous operation completes or until the current time exceeds the value specified by _Abs_time.

Public Operators

Name Description
operator std::shared_future<void> Implicitly converts the completion_future object to an std::shared_future object.
operator= Copies the contents of the specified completion_future object into this one.

Inheritance Hierarchy

completion_future

Requirements

Header: amprt.h

Namespace: concurrency

completion_future

Initializes a new instance of the completion_future class.

Syntax

completion_future();

completion_future(
    const completion_future& _Other );

completion_future(
    completion_future&& _Other );

Parameters

_Other
The completion_future object to copy or move.

Overloads List

Name Description
completion_future(); Initializes a new instance of the completion_future Class
completion_future(const completion_future& _Other); Initializes a new instance of the completion_future class by copying a constructor.
completion_future(completion_future&& _Other); Initializes a new instance of the completion_future class by moving a constructor.

get

Waits until the associated asynchronous operation completes. Throws the stored exception if one was encountered during the asynchronous operation.

Syntax

void get() const;

operator std::shared_future<void>

Implicitly converts the completion_future object to an std::shared_future object.

Syntax

operator std::shared_future<void>() const;

Return Value

An std::shared_future object.

operator=

Copies the contents of the specified completion_future object into this one.

Syntax

completion_future&  operator= (const completion_future& _Other );
completion_future&  operator= (completion_future&& _Other );

Parameters

_Other
The object to copy from.

Return Value

A reference to this completion_future object.

Overloads List

Name Description
completion_future& operator=(const completion_future& _Other); Copies the contents of the specified completion_future object into this one, using a deep copy.
completion_future& operator=(completion_future&& _Other); Copies the contents of the specified completion_future object into this one, using a move assignment.

then

Chains a callback function object to the completion_future object to be executed when the associated asynchronous operation finishes execution.

Syntax

template <typename _Functor>
void then(const _Functor & _Func ) const;

Parameters

_Functor
The callback functor.

_Func
The callback function object.

to_task

Returns a task object corresponding to the associated asynchronous operation.

Syntax

concurrency::task<void> to_task() const;

Return Value

A task object corresponding to the associated asynchronous operation.

valid

Gets a Boolean value that indicates whether the object is associated with an asynchronous operation.

Syntax

bool valid() const;

Return Value

true if the object is associated with an asynchronous operation; otherwise, false.

wait

Blocks until the associated asynchronous operation completes.

Syntax

void wait() const;

wait_for

Blocks until the associated asynchronous operation completes or the time that's specified by _Rel_time has elapsed.

Syntax

template <
    class _Rep,
    class _Period
>
std::future_status::future_status wait_for(
    const std::chrono::duration< _Rep, _Period>& _Rel_time ) const;

Parameters

_Rep
An arithmetic type that represents the number of ticks.

_Period
A std::ratio that represents the number of seconds that elapse per tick.

_Rel_time
The maximum amount of time to wait for the operation to complete.

Return Value

Returns:

  • std::future_status::deferred if the associated asynchronous operation is not running.

  • std::future_status::ready if the associated asynchronous operation is finished.

  • std::future_status::timeout if the specified time period has elapsed.

wait_until

Blocks until the associated asynchronous operation completes or until the current time exceeds the value specified by _Abs_time.

Syntax

template <
    class _Clock,
    class _Duration
>
std::future_status::future_status wait_until(
    const std::chrono::time_point< _Clock, _Duration>& _Abs_time ) const;

Parameters

_Clock
The clock on which this time point is measured.

_Duration
The time interval since the start of _Clock’s epoch, after which the function will time out.

_Abs_time
The point in time after which the function will time out.

Return Value

Returns:

  1. std::future_status::deferred if the associated asynchronous operation is not running.

  2. std::future_status::ready if the associated asynchronous operation is finished.

  3. std::future_status::timeout if the time period specified has elapsed.

~completion_future

Destroys the completion_future object.

Syntax

~completion_future();

See also

Concurrency Namespace (C++ AMP)