ExcludeUpdateRgn function (winuser.h)

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

See also

BeginPaint

GetUpdateRect

GetUpdateRgn

Painting and Drawing Functions

Painting and Drawing Overview

UpdateWindow