From: akl <twinandi@...>
Date: 2008-05-05T04:05:04+09:00
Subject: Re: Don't wait for Exception in threads

Hi Emil,

Emil Sandin schrieb:
> I have two threads running in parallell, like this:
> 
> ####################
> 
> t1=Thread.new{
>   50.times{
>     p "thread one"
>     sleep 0.1
>   }
> }
> 
> t2=Thread.new{
>   p "thread two"
>   raise "error in thread two"
> }
> 
> t1.join
> t2.join
> 
> #################
> The output is:
> "thread one"
> "thread two"
> "thread one"
> ... 48 times more "thread one"
> "thread one"
> testscript.rb:15: error in thread two (RuntimeError)
>   from testscript.rb:19:in `join'
>   from testscript.rb:19
> 
> The program waits for the first thread to complete before telling me
> that the second one raised an exception.
> I don't want to wait until the first thread finishes to see the
> exception, I want to see it right away.
> How can I do that?

You can do something like:

Thread.abort_on_exception = true
t = []
t << Thread.new {
   50.times{
     p "thread one"
     sleep 0.1
   }
}
t << Thread.new {
   p "thread two"
   raise "error in thread two"
}
t.each {|t| t.join }

I dont have tested the example, but this way you should see the Exception in the 
Moment it occurs

Andi