safest way to kill a thread

[martinnitram at excite.com]

limodou wrote:
>Using Thread's method setDaemon() before you call the start() method.
>Just like :
>t.setDaemon(True)
>t.start()
thank for fast reply.
from python.org doc, said that setDaemon() function as
"The entire Python program exits when no active non-daemon threads
are left."
is it mean that when the main program exit (normally/abnormally), all
threads created will also exit?
  Thank again.