DDREGISTERCALLBACK structure (ddkmapi.h)
The DDREGISTERCALLBACK structure contains the register callback information. This structure is used by both the DD_DXAPI_REGISTER_CALLBACK and DD_DXAPI_UNREGISTER_CALLBACK function identifiers of the DxApi function.
Syntax
typedef struct _DDREGISTERCALLBACK {
HANDLE hDirectDraw;
ULONG dwEvents;
LPDD_NOTIFYCALLBACK pfnCallback;
ULONG_PTR dwParam1;
ULONG_PTR dwParam2;
PVOID pContext;
} DDREGISTERCALLBACK, *LPDDREGISTERCALLBACK;
Members
hDirectDraw
Specifies the Microsoft DirectDraw handle.
dwEvents
Defines the event that should trigger the callback. The values in dwParam1 and dwParam2 depend on the event. The following events are defined:
Event | Description | dwParam1,dwParam2 |
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DDEVENT_DISPLAY_VSYNC | Called every time a display V-sync occurs. |
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DDEVENT_POSTDOSBOX | Called after returning from a full-screen MS-DOS box or the security dialog box (appears when CTRL+ALT+DELETE is pressed). |
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DDEVENT_POSTRESCHANGE | Called after a mode change occurs. |
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DDEVENT_PREDOSBOX | Called before entering a full-screen MS-DOS box or the security dialog box (appears when CTRL+ALT+DELETE is pressed). |
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DDEVENT_PRERESCHANGE | Called before a mode change occurs. |
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DDEVENT_VP_LINE | Sets an IRQ to occur each time the hardware video port writes the specified line and then calls the callback each time the IRQ is triggered. |
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DDEVENT_VP_VSYNC | Called each time a hardware video port V-sync occurs. |
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pfnCallback
Points to a pfnCallback callback function that is called when the event that is specified by the dwEvents member occurs.
dwParam1
Defined by the dwEvents member.
dwParam2
Defined by the dwEvents member.
pContext
Contains client data that is passed back to the client if the pfnCallback callback function is called.
Requirements
Requirement | Value |
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Header | ddkmapi.h (include Ddkmapi.h) |