Int 2F Fn D44D  - 4dos.com V2.1+ - Api                                     [l]

   AX = D44Dh
   BH = function
       00h installation check

       Return: AX = 44DDh
           BL = major version number
           BH = minor version number
           CX = PSP segment address for current invocation
           DL = 4DOS shell number (0 for the first (root) shell,
                 updated each time a new copy is loaded)
       01h (internal, v2.1-3.03) terminate current copy of 4DOS

       Return: nothing
       (internal, v4.0+) ???

       Return: AX = 44DDh
           ES:BX -> data area (see #2758)
       02h ???
       DX = ???

       Note:   v5.52 signals "unrecoverable error" and then terminates
             with INT 21/AH=4Ch or enters a deliberate infinite
             loop if ???
   ---v2.1-3.03 only---
       03h EXEC program
       CX:DX -> EXEC record (see #2759)
       FEh deallocate shell number (passed through to root shell)
       ???
       FFh allocate shell number (passed through to root shell)
   ---v5.52---
       03h get ???
       BL = ??? (00h/01h)

       Return: DX = current value of ???
       04h set ???
       BL = ??? (00h/01h)
       DX = new value for ???

Note:  a bug in v3.00 will crash the system if unrecognized value in BH

See Also: AX=D44Eh,AX=D44Fh/BX=0000h,AX=E44Dh,INT 21/AX=4403h"DOS"

See Also: INT 14/AX=7000h
Index: installation check;4DOS|installation check;NDOS

Format of 4DOS v4.0 data area:
Offset Size    Description (Table 2758)
 00h  2 BYTEs  ???
 06h   WORD    XMS handle for swapping
   ???

See Also: #2759

Format of 4DOS EXEC v2.1-v3.03 record:
Offset Size    Description (Table 2759)
 00h   WORD    offset of ASCIZ program name in same segment as EXEC record
 02h   WORD    offset of DOS commandline in same segment as EXEC record
 04h   WORD    segment of environment for child process (see INT 21/AH=26h)

See Also: #2758