From: Pat Maddox <pergesu@...>
Date: 2006-04-23T20:35:30+09:00
Subject: Re: How do threads and join work?

On 4/23/06, Ashley Moran <work@ashleymoran.me.uk> wrote:
>
> On Apr 23, 2006, at 11:06 am, Pat Maddox wrote:
>
> > running = true
> > t = Thread.new do
> >   print "Thread started\n"
> >   while(running); end
> >   print "Thread finished\n"
> > end
> >
> > t.join
> > puts "After join"
> > running = false
> > puts "Program finished"
> >
> > The paragraph I quoted makes me think that it should print "Thread
> > started...After join...Thread finished...Program finished"  It joins
> > the thread and continues processing, setting running to false, which
> > causes the thread's loop to end.  Also not that it could say "Program
> > finished...Thread finished", I don't think there's a way to know for
> > sure.
>
>
> Your thread never actually finished, because you joined on it before
> you set the value of running to false, so your code blocks at that
> point.

Right, I mentioned that in my OP.  I want to know if there's a way to
get join-like behavior - do not terminate the program until that
thread has finished executing - without blocking.


>You need to swap the last lines like this:
>
>    running = true
>    t = Thread.new do
>      print "Thread started\n"
>      while(running); puts "running = #{running}"; sleep 1; end
>      puts "running = #{running}";
>      print "Thread finished\n"
>    end
>
>    sleep 5
>
>    puts "Before join"
>    running = false
>    t.join
>    puts "After join"
>    puts "Program finished"
>
> I added two things into the while loop: a sleep so you don't run your
> CPU at 100% and a ticker.

This gives the output I want, but doesn't actually perform what I
want.  The ultimate goal here is to basically tell my program "Go
start doing this in the background, and I'm going to keep working."

Pat