From: Robert Klemme <bob.news@...>
Date: 2004-10-29T16:38:57+09:00
Subject: Re: Thread::list and GC


"Bill Kelly" <billk@cts.com> schrieb im Newsbeitrag
news:003b01c4bd78$530e7c80$6442a8c0@musicbox...
> From: "Ara.T.Howard" <Ara.T.Howard@noaa.gov>
> >
> >    are there any issues with iterating Thread::list - since this list
is
> >    obviously changing all the time in this code (new Threads started)
>
> Maybe,
>
>   while th = Thread::list.find {|t| t != Thread.current}
>     begin
>       th.join
>     rescue => e
>       warn{ e }
>     end
>   end

This does not make a difference as Thread.list() creates a new array on
each invokation:

>> Thread.list().id
=> 135026036
>> Thread.list().id
=> 135022100
>> Thread.list().id
=> 135018212

So you can safely walk through the array as long as you like.  Threads are
GC'ed after termination:

09:32:51 [ruby]: ./th-list.rb
[#<Thread:0x100f59f8 run>]
..
[#<Thread:0x100e6878 sleep>, #<Thread:0x100f59f8 run>]
[#<Thread:0x100f59f8 run>]
[#<Thread:0x100f59f8 run>]
09:32:55 [ruby]: cat th-list.rb
#!/usr/bin/ruby

p Thread.list

Thread.new do
  puts "."
  sleep 1
end

p Thread.list
sleep 1
p Thread.list
GC.start
p Thread.list
09:32:57 [ruby]:

The std lib contains a class that helps with the termination of multiple
threads:
http://www.ruby-doc.org/stdlib/libdoc/thwait/rdoc/index.html

Kind regards

    robert