Releasing the memory and the system resources before exiting an application is a good practice on all operating systems. On early versions of Microsoft Windows (3.1, 95), it was critical; the system had a very limited number of GDI resources (colors, fonts, and so on) and they were not automatically released. Later versions (NT 4, 2000, XP) have improved this behaviour. However, it is still highly recommanded to provide a clean way to quit an application, freeing the memory and releasing system resources before exiting. A convenient way to do so is to write a function that frees the application data, deletes the IlvDisplay and call IlvExit(0). This function may then be used as an accelerator, a button callback, a top window destroy callback, or the like.