MFCancelWorkItem function (mfapi.h)

Attempts to cancel an asynchronous operation that was scheduled with MFScheduleWorkItem or MFScheduleWorkItemEx.


HRESULT MFCancelWorkItem(


[in] Key

The key that was received in the pKey parameter of the MFScheduleWorkItem, MFScheduleWorkItemEx, or MFPutWaitingWorkItem functions.

Return value

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.


Because work items are asynchronous, the work-item callback might still be invoked after MFCancelWorkItem is called.

This function is available on the following platforms if the Windows Media Format 11 SDK redistributable components are installed:

  • Windows XP with Service Pack 2 (SP2) and later.
  • Windows XP Media Center Edition 2005 with KB900325 (Windows XP Media Center Edition 2005) and KB925766 (October 2006 Update Rollup for Windows XP Media Center Edition) installed.


Requirement Value
Minimum supported client Windows Vista [desktop apps | UWP apps]
Minimum supported server Windows Server 2008 [desktop apps | UWP apps]
Target Platform Windows
Header mfapi.h
Library Mfplat.lib
DLL Mfplat.dll

See also

Media Foundation Functions

Work Queues