Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: notesfiles - hp 1.2 08/01/83; site hp-pcd.UUCP Path: utzoo!linus!decvax!tektronix!hplabs!hp-pcd!bill From: bill@hp-pcd.UUCP (bill) Newsgroups: net.micro.pc Subject: MS-DOS function 37h Message-ID: <15200001@hpcvlo.UUCP> Date: Tue, 9-Jul-85 13:44:00 EDT Article-I.D.: hpcvlo.15200001 Posted: Tue Jul 9 13:44:00 1985 Date-Received: Mon, 15-Jul-85 01:43:47 EDT Organization: Hewlett-Packard - Corvallis, OR Lines: 29 Nf-ID: #N:hpcvlo:15200001:000:788 Nf-From: hpcvlo!bill Jul 9 09:44:00 1985 Somebody a while back asked about MS-DOS function 37h, mentioning that it responded to AL values of 0, 1, 2, and 3 ... but couldn't figure out what the last two functions were supposed to do. I don't know about later versions, but in MS-DOS 2.11 the functions are: Specify: AH=37h AL=0 Read switch character (returns current character in DL) 1 Set switch character (specify new character in DL) 2 Read device availability (as set by function AL=3) 3 Set device availability, where: DL=0 means /DEV/ must preceed device names DL#0 means /DEV/ need not preceed device names Returns: DL = Switch character (if AL=0 or 1) Device availability flag (if AL=2 or 3) Error return: AL=0FFh means the value in AL was not in the range 0-3. Bill Frolik hp-pcd!bill