bill@hp-pcd.UUCP (bill) (07/09/85)
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