Changes the root directory of the current process to directory. Palauttaa TRUE jos onnistui, FALSE jos epäonnistui..
Huomaa: It's not wise to use this function when running in a webserver environment, because it's not possible to reset the root directory to / again at the end of the request. This function will only function correct when you run PHP as command line too. (CLI)
Huomaa: Tätä funktiota ei löydy Windows-alustalla.