From: Bill Kelly <billk@...>
Date: 2004-10-31T09:54:52+09:00
Subject: Re: Thread::list and GC

From: "Robert Klemme" <bob.news@gmx.net>
>
> >> >   while th = Thread::list.find {|t| t != Thread.current}
> >> >     begin
> >> >       th.join
> >> >     rescue => e
> >> >       warn{ e }
> >> >     end
> >> >   end
>
> But: this solution has a problem.  You can't ensure that it terminates.  You 
> will have to set some kind of flag somewhere that no new threads are created 
> anyway.  *If* you do that, you can just as easily wait once for all 
> currently running threads *after* the flag has been set because you know 
> there will be no new threads.

I did think about that, whether it would terminate... But I'd
guessed that practically speaking the only scenario in which it
wouldn't terminate is if the threads we're trying to join are
themselves just spawning new threads like crazy.  Kind of like
a fork() bomb, but with threads... :)

I thought about making it fancier with raising our own
Thread priority, and/or using Thread.critical... But I was 
guessing that in a reasonably well-behaved system, the liklihood
of the above code not terminating was pretty much nil. . . .
So I was betting we wouldn't need to worry about it.  Does it
seem the above would be likely to not terminate outside of
extreme cases like a "fork() bomb with threads" ?


Regards,

Bill