Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

 ◄Detail►                                    ◄Up► ◄Contents► ◄Index► ◄Back►
────────────────────────────────────────────────────────────────────────────
 
  Interrupt:   21h     Function:   44h   Subfunction:   02h
 
  Title:       IOCTL: Read Control Data from Character Device Driver
 
  Description:
 
     Reads control data from a character device driver. The length and
     contents of the data are specific to each device driver and do not
     follow any standard format. This function does not necessarily
     result in any input from the physical device.
 
     Input                                 Output
 
     AH = 44h                              If function successful
     AL = 02h                                Carry flag: clear
     BX = Handle                             AX = Bytes read and
     CX = Number of bytes to read                 buffer contains
     DS:DX = segment:offset of buffer             control data from
                                                  driver
 
                                           If function unsuccessful
                                             Carry flag: set
                                             AX = Error code (01h, 05h,
                                                  06h, or 0Dh)
                                             See: ◄Error codes►
                                    -♦-