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
| 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) |