Int 2F Fn 122E  U - DOS 4+ Internal - Get Or Set Error Table Addresses     [D]

   AX = 122Eh
   DL = subfunction
       00h get standard DOS error table

       Return: ES:DI -> error table
                (DOS 4: errors 00h-12h,50h-5Bh)
                (DOS 5: errors 00h-26h,4Fh,51h-59h)
       01h set standard DOS error table
       ES:DI -> error table
       02h get parameter error table (errors 00h-0Ah)

       Return: ES:DI -> error table
       03h set parameter error table
       ES:DI -> error table
       04h get critical/SHARE error table (errors 13h-2Bh)

       Return: ES:DI -> error table
       05h set critical/SHARE error table
       ES:DI -> error table
       06h get ??? error table

       Return: ES:DI -> error table or 0000h:0000h
       07h set ??? error table
       ES:DI -> error table
       08h get error message retriever (see below)

       Return: ES:DI -> FAR procedure to fetch error message
       09h set ??? error table
       ES:DI -> error table

Notes: if the returned segment on a "get" is 0001h, then the offset specifies
     the offset of the error message table within COMMAND.COM, and the
     procedure returned by DL=08h should be called
   DOS 5+ COMMAND.COM does not allow setting any of the addresses (calls
     with DL odd are ignored); they are always returned with segment 0001h
   for DOS 5.0, the standard and critical/SHARE error tables are combined
     into a single error table

See Also: AX=0500h,INT 21/AH=59h

Format of DOS 4.x error table:
Offset Size    Description
 00h   BYTE    FFh
 01h  2 BYTEs  04h,00h (DOS version???)
 03h   BYTE    number of error headers following
 04h 2N WORDs  table of all error headers for table
       Offset  Size    Description
        00h    WORD    error message number
        02h    WORD    offset of error message from start of header
               error messages are count byte followed by msg

Note:  DOS 5 error tables consist of one word per error number; each word
     contains either the offset of a counted string or 0000h

Call error retrieval function with:
   AX = error number
   DI = offset of error table

Return: ES:DI -> error message (counted string)

Notes: this function needs to access COMMAND.COM if the messages were not
     loaded into memory permanently with /MSG; the caller should assume
     that the returned message will be overwritten by the next call of
     the function
   supported by DR-DOS 5.0

Values for parameter errors:
 01h   Too many parameters
 02h   Required Parameter missing
 03h   Invalid switch
 04h   Invalid keyword
 06h   Parameter value not in allowed range
 07h   Parameter value not allowed
 08h   Parameter value not allowed
 09h   Parameter format not correct
 0Ah   Invalid parameter
 0Bh   Invalid parameter combination