Windows 3.1 Device Drivers (ddag31qh.hlp) (Table of Contents; Topic list)
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GetDisplayUpd
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WORD GetDisplayUpd(lpPntStruc, wParam, lParam)
LPEXTPAINTSTRUC lpPntStruc;
WORD wParam;
DWORD lParam;
 
The GetDisplayUpd function calls the virtual-display device (VDD) to get a
display update (if any) and stores it in the EXTPAINTSTRUC structure.
 
It prevents any further changes from occurring in or to the application. The
application restarts after a call to one of the following functions:
UpdateScreen, PaintScreen, or GrbUnLockApp.
 
Parameter   Description
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lpPntStruc  Points to an EXTPAINTSTRUC structure.
 
wParam      Specifies the 16-bit message parameter. It is -1 if WINOLDAP
            origin.
 
lParam      Specifies the 32-bit message parameter. It is 0 if WINOLDAP
            origin.
 
Return Value
 
The return value is a display update flag. It can be a combination of the
following values.
 
Value                  Meaning
────────────────────────────────────────────────────────────────────────────
fDisp_Ctlr (8)         Indicates controller-state change.
 
fDisp_VRAM (16)        Indicates video RAM change.
 
fDisp_Curs (32)        Indicates cursor change.
 
fDisp_HCurTrack (128)  Horizontal cursor track is required.
 
Comments
 
The export ordinal for this function is 18.
 
This function "locks" the application (prevents further changes from
occurring). The application can be started again by calling the
UpdateScreen, PaintScreen, or GrbUnLockApp functions.
 
See Also
 
GrbUnLockApp, PaintScreen, UpdateScreen, EXTPAINTSTRUC