canceling and joining threads

[sir_alex]

1) no, i didn't; i'll go and read that function
2) well, the actual situation is: there's the main thread (the
application itself) and then the second thread that i create with
threading.Thread, in which i make some things; in this thread i call
gtk.gdk to update a window with a progress bar...
3) i'm on linux (ubuntu, specifically, but i don't think the distro is
important...)