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The ExcludeUpdateRgn function prevents drawing within invalid areas of a window by excluding an updated region in the window from a clipping region.
Syntax
int ExcludeUpdateRgn(
[in] HDC hDC,
[in] HWND hWnd
);
Parameters
[in] hDC
Handle to the device context associated with the clipping region.
[in] hWnd
Handle to the window to update.
Return value
The return value specifies the complexity of the excluded region; it can be any one of the following values.
| Value | Meaning |
|---|---|
| COMPLEXREGION | Region consists of more than one rectangle. |
| ERROR | An error occurred. |
| NULLREGION | Region is empty. |
| SIMPLEREGION | Region is a single rectangle. |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | winuser.h (include Windows.h) |
| Library | User32.lib |
| DLL | User32.dll |