qa.hlp (Table of Contents; Topic list)
Int 21H Function 44H Subfunction 01H
   Summary  Notes  Back
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  Description:  IOCTL: Set Device Information
 
  Sets certain flags for a handle associated with a character device. This
  subfunction may not be used for a handle that is associated with a file.
 
  Input                                           Output
  ════════════════════════════════════            ════════════════════════
  AH=44H                                          If function successful
  AL=01H                                          Carry flag=clear
  BX=handle                                       If function unsuccessful
  DX=device information word                      Carry flag=set
     bits 8-15 = 0 (reserved)                     AX=error code
     bit  7    = 1 indicating a device
     bit  6    = 0 (reserved)
     bit  5    = 0 to select ASCII
                  ("cooked") mode
                 1 to select binary
                  ("raw") mode
     bit  4    = 0 (reserved)
     bit  3    = 1 if clock device
     bit  2    = 1 if NUL device
     bit  1    = 1 if standard output
     bit  0    = 1 if standard input
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