ValidateRgn

The ValidateRgn function validates the client area within a region by removing the region from the current update region of the specified window.

BOOL ValidateRgn(
  HWND hWnd,  // handle of window
  HRGN hRgn   // handle of valid region
);
 

Parameters

hWnd

Handle to the window whose update region is to be modified.

hRgn

Handle to a region that defines the area to be removed from the update region. If this parameter is NULL, the entire client area is removed.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero.

Windows NT: To get extended error information, call GetLastError.

Remarks

The specified region must have been created by a region function. The region coordinates are assumed to be client coordinates.

The BeginPaint function automatically validates the entire client area. Neither the ValidateRect nor ValidateRgn function should be called if a portion of the update region must be validated before the next WM_PAINT message is generated.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winuser.h.
  Import Library: Use user32.lib.

See Also

Painting and Drawing Overview, Painting and Drawing Functions, BeginPaint, ExcludeUpdateRgn, InvalidateRect, InvalidateRgn, ValidateRect, WM_PAINT