PUNREGISTER_EVENT_CALLBACK callback function (hdaudio.h)

Article
10/21/2021

The UnregisterEventCallback routine deletes the registration of an event callback that was previously registered by a call to RegisterEventCallback.

The function pointer type for an UnregisterEventCallback routine is defined as follows.

Syntax

PUNREGISTER_EVENT_CALLBACK PunregisterEventCallback;

NTSTATUS PunregisterEventCallback(
  [in] PVOID _context,
  [in] UCHAR Tag
)
{...}

Parameters

[in] _context

Specifies the context value from the Context member of the HDAUDIO_BUS_INTERFACE, HDAUDIO_BUS_INTERFACE_V2, or HDAUDIO_BUS_INTERFACE_BDL structure.

[in] Tag

Specifies the tag value that was associated with the callback by the preceding call to RegisterEventCallback.

Return value

UnregisterEventCallback returns STATUS_SUCCESS if the call succeeds in changing the DMA engines' states. Otherwise, the routine returns an appropriate error code. The following table shows a possible return status code.

Return code	Description
STATUS_INVALID_PARAMETER	Indicates that the specified tag is not valid.

Remarks

Before calling this routine, the function driver is responsible for programming the codec or codecs to remove the association of the callback with the specified tag.

Requirements

Requirement	Value
Target Platform	Desktop
Header	hdaudio.h (include Hdaudio.h)
IRQL	PASSIVE_LEVEL