The ExcludeUpdateRgn function prevents drawing within invalid areas of a window by excluding an updated region in the window from a clipping region.
int ExcludeUpdateRgn(
| HDC hDC, | // handle to device context |
| HWND hWnd | // handle to window |
| ); |
Parameters
hDC
Identifies the device context associated with the clipping region.
hWnd
Identifies the window to update.
Return Values
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. |
See Also