Jef Driesen f6d35fa2c2 Add cancellation support.
To be able to cancel an operation, an application should register a
callback function that returns a non-zero value whenever the active
operaton should be cancelled. A backend can invoke this callback function
to query the application for a pending cancellation request.
2010-02-15 13:16:26 +00:00
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2010-02-15 13:16:26 +00:00