LPDD_NOTIFYCALLBACK callback function (ddkmapi.h)

Article
02/22/2024

The NotifyCallback callback function performs operations related to an event that occurred.

Syntax

LPDD_NOTIFYCALLBACK LpddNotifycallback;

ULONG LpddNotifycallback(
  DWORD dwFlags,
  PVOID pContext,
  DWORD dwParam1,
  DWORD dwParam2
)
{...}

Parameters

dwFlags

Indicates the event that caused the callback to be called. The values in dwParam1 and dwParam2 depend on the value of dwFlags. The following values are possible:

Flag	dwParam1	dwParam2
DDNOTIFY_CLOSECAPTURE	hCapture	unused
DDNOTIFY_CLOSEDIRECTDRAW	hDirectDraw	unused
DDNOTIFY_CLOSESURFACE	hSurface	unused
DDNOTIFY_CLOSEVIDEOPORT	hVideoPort	unused
DDNOTIFY_DISPLAY_VSYNC	hDirectDraw	unused
DDNOTIFY_POSTDOSBOX	hDirectDraw	unused
DDNOTIFY_POSTRESCHANGE	hDirectDraw	unused
DDNOTIFY_PREDOSBOX	hDirectDraw	unused
DDNOTIFY_PRERESCHANGE	hDirectDraw	unused
DDNOTIFY_VP_LINE	hVideoPort	unused
DDNOTIFY_VP_VSYNC	hVideoPort	unused

pContext

Contains a value that the caller passed in a call to the DxApi function along with a specific function identifier. For more information about function identifiers, see DxApi.

dwParam1

Handle to the object related to the event that caused the callback to be called.

dwParam2

Unused.

Return value

NotifyCallback returns zero.

Remarks

A video capture driver supplies a NotifyCallback callback function to the DirectDraw runtime when the video capture driver calls the runtime's DxApi function. For more information, see Notify Callback Functions in a Video Capture Driver.

Requirements

Requirement	Value
Target Platform	Desktop
Header	ddkmapi.h (include Ddkmapi.h)