MFAddPeriodicCallback function (mfapi.h)

Sets a callback function to be called at a fixed interval.


HRESULT MFAddPeriodicCallback(
  [in]  IUnknown           *pContext,
  [out] DWORD              *pdwKey


[in] Callback

Pointer to the callback function, of type MFPERIODICCALLBACK.

[in] pContext

Pointer to a caller-provided object that implements IUnknown, or NULL. This parameter is passed to the callback function.

[out] pdwKey

Receives a key that can be used to cancel the callback. To cancel the callback, call MFRemovePeriodicCallback and pass this key as the dwKey parameter.

Return value

The function returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return code Description
The function succeeded.


To get the timer interval for the periodic callback, call MFGetTimerPeriodicity.


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

See also

Media Foundation Functions

Work Queues