Puppet

#!/usr/bin/ruby

# This program creates some threads, forks, and then

# sees how many threads are in the child and parent.

require 'sync'

class Checker 

        attr_accessor :sync, :threads

        def initialize()

                @threads = []

                @sync = Sync.new

        end

        def run

                (1..10).to_a.each do |i| 

                        @threads << Thread.new(i) do |j| 

                                print "PRE th[#{j}] sees #{Thread.list.length} threads\n" 

sync.synchronize do

                                pid = fork do

                                        sleep 3 

                                        print "inside #{j}'s child process\n"

#                                        sync.synchronize do

                                                IO.popen("cat > /dev/null", "w") do |p|

                                                        p.puts j

                                                end

#                                        end

                                end

                                Process.wait(pid)

                                print "POST th[#{j}] sees #{Thread.list.length} threads\n"

                        end

end

                end

                @threads.each {|th| th.join}

        end

end

c = Checker.new

c.run