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documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

   ◄Summary►  ◄Notes►  ◄Back►
──────────────────────────────────────────────────────────────────────────────
 
  Description:  IOCTL: Write Control Data to Block
                Device Driver
 
  Transfers control data from an application program directly to a block
  device driver. The length and contents of the control data are specific
  to each device driver and do not follow any standard format. This func-
  tion does not necessarily result in any output to the physical device.
 
  Input                                   Output
  ════════════════════════════            ════════════════════════════════
  AH=44H                                  If function successful
  AL=05H                                  Carry flag=clear
  BL=drive code (0 = default,             AX=bytes transferred
      1=A, 2=B, etc.)                     If function unsuccessful
  CX=number of bytes to write             Carry flag=set
  DS:DX=segment:offset of data            AX=error code
                                    -♦-