Int 21 Fn 5FE0  C - LANtastic - Get DOS Service Vector                     [N]

   AX = 5FE0h

Return: CF clear if successful
       ES:BX -> current FAR service routine
   CF set on error
       AX = error code

Note:  the service routine is called by the LANtastic redirector whenever DOS
     may safely be called, permitting external TSRs and drivers to hook
     into LANtastic's DOS busy flag checking

See Also: AX=5FE1h,INT 28,INT 2A/AH=84h