Int 2F Fn 112E  CU - Network Redirector (dos 4.0+) - Extended Open/create  [N]

   AX = 112Eh
   SS = DS = DOS DS
   ES:DI -> uninitialized SFT for file
   STACK: WORD file attribute for created/truncated file
           low byte = file attributes
           high byte = 00h normal create/open, 01h create new file
   SDA first filename pointer -> fully-qualified filename
   SDA extended file open action = action code
         (see #1459 at INT 21/AX=6C00h)
   SDA extended file open mode = open mode for file (see INT 21/AX=6C00h)

Return: CF set on error
       AX = error code
   CF clear if successful
       CX = result code
       01h file opened
       02h file created
       03h file replaced (truncated)
       SFT initialized (except handle count, which DOS manages itself)

Note:  this function is called by the DOS 4.0+ kernel
BUG:   this function is not called correctly under some DOS versions
     (at least 5.0 and 6.2):
       the file attribute on the stack is not correct if the action
         code is 11h,
       the result code in CX is not passed back to the application.

See Also: AX=1115h,AX=1116h,AX=1117h,INT 21/AX=6C00h