UpdateWindow function Null safety user32

int UpdateWindow(
  1. int hWnd

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.

BOOL UpdateWindow(
  HWND hWnd


int UpdateWindow(int hWnd) => _UpdateWindow(hWnd);