Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
INT 21,44 - I/O Control for Devices (IOCTL)
Standard Call Format
AH = 44h
AL = function value
BX = file handle
BL = logical device number (0=default, 1=A:, 2=B:, 3=C:, ...)
CX = number of bytes to read or write
DS:DX = data or buffer
on return:
AX = error code if CF set
AX = # of bytes transferred if CF not set
For more information, see the following topics:
IOCTL,0 Get Device Information
IOCTL,1 Set Device Information
IOCTL,2 Read From Character Device
IOCTL,3 Write to Character Device
IOCTL,4 Read From Block Device
IOCTL,5 Write to Block Device
IOCTL,6 Get Input Status
IOCTL,7 Get Output Status
IOCTL,8 Device Removable Query
IOCTL,9 Device Local or Remote Query
IOCTL,A Handle Local or Remote Query
IOCTL,B Set Sharing Retry Count
IOCTL,C Generic I/O for Handles
IOCTL,D Generic I/O for Block Devices (3.2+)
IOCTL,E Get Logical Drive (3.2+)
IOCTL,F Set Logical Drive (3.2+)
- see: DEVICE COMMAND CODES
DEVICE REQUEST HEADER
DEVICE STATUS
DEVICE HEADER
DEVICE ATTRIBUTES
[helppc.bosbyte.nl] int 21,44