Spawn children and/or take other resources? Clean it all when out of scope!

finalizer.rb

# Use ObjectSpace.define_finalizer, as
# inspired by the Ruby std library (tmpfile.rb) 
class C
  def initialize
    @child_pid = fork do
      sleep 1000
    end
    Process.detach(@child_pid) if @child_pid
    ObjectSpace.define_finalizer self, Killer.new(@child_pid)
  end
  def do_somthing
    'hi!'
  end
  class Killer
    def initialize(pid)
      @pid = pid
    end
    # mimic a proc-like behavior (Walks Like A Duck) 
    def call(*args)
      Process.kill('TERM', @pid)
    end
  end
end

# convenience method
class Array
  def random_element
    return self[rand(length)] 
  end
end

# everything may go wrong in real life
ALL_EXCEPTIONS        =
    ObjectSpace.each_object(Class).select{|x| x.ancestors.include? Exception}
ALL_SIGNALS           = 
    Signal.list.keys

EXCEPTION_PROBABILTY  = 0.025
SIGNAL_PROBABILITY    = 0.025

def randomly_except
  raise ALL_EXCEPTIONS.random_element, "(Randomly generated exception)"  if 
      rand < EXCEPTION_PROBABILTY
end
def randomly_signal
  Process.kill(ALL_SIGNALS.random_element, 0)                            if
      rand < SIGNAL_PROBABILITY
end

# the test program
pool = []
while(sleep 0.5) do
  pool << C.new # consume machine resources ;-)
  randomly_except
  randomly_signal
end