Status XGetTransientForHint(display, w, prop_window_return)
      Display *display;
      Window w;
      Window *prop_window_return;
| display | Specifies the connection to the X server. | 
| w | Specifies the window. | 
| prop_window_return | Returns the WM_TRANSIENT_FOR property of the specified window. | 
XGetTransientForHint() can generate a BadWindow error.
| BadWindow | A value for a Window argument does not name a defined Window. |