From: Issac <issac@...>
Date: 2001-12-09T11:44:11+09:00
Subject: [ruby-talk:27987] mutex problem

As a Ruby newbie, I've been excitedly plowing through the Thomas/Hunt book.
But now I'm stuck.  On pp. 118-119 there's a piece of code that doesn't seem
to
work:

require 'thread'
mutex = Mutex.new
count1 = count2 = 0
difference = 0
counter = Thread.new do
  loop do
    mutex.sychronize do
      count1 += 1
      count2 += 1
    end
  end
end
spy = Thread.new do
  loop do
    mutex.synchronize do
      difference += (count1 - count2).abs
    end
  end
end
sleep 1
mutex.lock
puts "count1 = #{count1}"
puts "count2 = #{count2}"
puts "difference = #{difference}"

When I run this on ruby 1.6.5 (2001-09-19) [i386-cygwin] from the cygwin
command line, it hangs.  It also hangs when I run it in RubyWin 0.0.3.8
with the same version of ruby.

Can anyone help?