Int 15 Fn 12  - Topview - Send Message - "len" - Get Object Length         [Q]

   AH = 12h
   BH = 09h
   BL = object
       00h handle in DWORD on top of stack
       window: get chars/line
       timer: get 1/100 seconds remaining before timer expires
       mailbox: (DV/X) get number of bytes queued to mailbox
       01h get number of chars/line in current task's default window
       0Ch (DV 2.26+) get chars/line in window owning handle on top of stk
       0Dh (DV 2.26+) get chars/line in parent task's window

Return: DWORD on top of stack is length

See Also: AH=12h/BH=08h