How to display busy cursor

void busy_stuff ()
{
  GdkDisplay *display;
  GdkCursor *cursor;
  GdkWindow *window;
  gint x, y;

  cursor = gdk_cursor_new(GDK_WATCH);
  display = gdk_display_get_default();
  window = gdk_display_get_window_at_pointer(disp, &x, &y);
		gdk_window_set_cursor(window, cursor);
  gdk_display_sync(display);
  gdk_cursor_unref(cursor);

  /* do time-consuming stuff here */
  gdk_window_set_cursor(window, NULL);

}