Int 21 Fn 440D  - Ms-dos 7.0 - Generic Ioctl - Get Current Lock State      [D]

   AX = 440Dh
   CX = 0870h (category code 08h, minor code 70h)
   BL = drive number (00h=default,01h=A:,etc)

Return: CF set on error
       AX = error code (01h,02h,etc.) (see #1366 at AH=59h/BX=0000h)
   CF clear if successful
       AX = current lock level (0-3) or FFFFh if not locked
       CX = lock permissions if AX<>FFFFh (see #1262)

See Also: AX=440Dh"DOS 3.2+",AX=440Dh/CX=086Ch