From: Joel VanderWerf <vjoel@...>
Date: 2004-05-06T01:52:55+09:00
Subject: Re: signaling another thread

Ara.T.Howard wrote:
> 
> what is is the prefered method in which one thread can 'signal' another thread
> on some condition?  Observable?  other?

One way is to use Thread#raise:

$ cat thread-signal.rb
   class PayAttention < Exception; end

   other = Thread.new do
     i=0
     begin
       loop do
         sleep 1
         i += 1 # important work
       end
     rescue PayAttention
       puts i
       retry if i < 10
     end
   end

   watch = Thread.new do
     loop do
       sleep 3
       other.raise PayAttention
     end
   end

   other.join

$ ruby thread-signal.rb
2
4
6
8
10
$