Int 2F Fn B706  - DOS 4+ Append - Get Append Function State                [-]

   AX = B706h

Return: BX = APPEND state
       bit 0: set if APPEND enabled
       bits 1-11 reserved
       bit 12: (DOS 5.0) set if APPEND applies directory search even if a
           drive has been specified
       bit 13: set if /PATH flag active
       bit 14: set if /E flag active (environment var APPEND exists)
       bit 15: set if /X flag active