MFAddPeriodicCallback function (mfapi.h)

Article
02/22/2024

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

Syntax

HRESULT MFAddPeriodicCallback(
  [in]  MFPERIODICCALLBACK Callback,
  [in]  IUnknown           *pContext,
  [out] DWORD              *pdwKey
);

Parameters

[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
S_OK	The function succeeded.

Remarks

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

Requirements

Requirement	Value
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