Int 15 Fn 12  - Topview - Send Message - "addr" - Get Handle Of Message S  [Q]

   AH = 12h
   BH = 03h
   BL = object
       00h mailbox handle in DWORD on top of stack
       02h sender of last msg read from mailbox (task's handle on stack)
       03h sender of last msg read from current task's mailbox

Return: DWORD on stack is task handle of message sender

See Also: AH=12h/BH=00h,AH=12h/BH=83h