cancellation_token Class

Article
10/30/2012

The cancellation_token class represents the ability to determine whether some operation has been requested to cancel.

class cancellation_token;

Members

Public Constructors

Name	Description
cancellation_token::cancellation_token Constructor	Overloaded. Constructs a cancellation_token object.
cancellation_token::~cancellation_token Destructor	Destructs the cancellation_token object.

Public Methods

Name	Description
cancellation_token::deregister_callback Method	Unregisters a callback function that is invoked when the cancellation token is canceled.
cancellation_token::is_cancelable Method	Returns an indication of whether this token can be canceled or not.
cancellation_token::is_canceled Method	Returns true if the token has been canceled.
cancellation_token::none Method	Returns a cancellation token which can never be subject to cancellation.
cancellation_token::register_callback Method	Registers a callback function that is invoked when the cancellation token is canceled.

Public Operators

Name	Description
cancellation_token::operator!= Operator	Determines whether two cancellation_token objects represent two different underlyign tokens.
cancellation_token::operator= Operator	Overloaded. Replaces the contents of one cancellation_token object with another.
cancellation_token::operator== Operator	Determines whether two cancellation_token objects represent the same underlying token.

Remarks

Multiple cancellation_token objects can be linked to one cancellation_token_source object. When you call the cancel method on a token source, all the linked cancellation_token objects are set as canceled.

A given cancellation_token object can be associated with a task_group, structured_task_group, or task to provide implicit cancellation. It can also be polled for cancellation information or have a callback registered and called when it is canceled.

cancellation_token behaves like a smart pointer and is safe to pass around by value.

For more info about task cancellation, see Cancellation in the PPL.

Inheritance Hierarchy

cancellation_token

Requirements

Header: ppl.h

Namespace: concurrency