UpdateWindow function (winuser.h)

The UpdateWindow function updates the client area of the specified window by sending a WM_PAINT message to the window if the window's update region is not empty. The function sends a WM_PAINT message directly to the window procedure of the specified window, bypassing the application queue. If the update region is empty, no message is sent.

Syntax

BOOL UpdateWindow(
  [in] HWND hWnd
);

Parameters

[in] hWnd

Handle to the window to be updated.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero.

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
API set ext-ms-win-ntuser-draw-l1-1-0 (introduced in Windows 8)

See also

ExcludeUpdateRgn

GetUpdateRect

GetUpdateRgn

InvalidateRect

InvalidateRgn

Painting and Drawing Functions

Painting and Drawing Overview

WM_PAINT