From: Robert Klemme <bob.news@...>
Date: 2005-06-20T06:05:34+09:00
Subject: Re: GC.disable not working?


"ts" <decoux@moulon.inra.fr> schrieb im Newsbeitrag 
news:200506191610.j5JGAeIU001389@moulon.inra.fr...
>>>>>> "E" == Eric Mahurin <eric_mahurin@yahoo.com> writes:
>
>
> E> I tried this on 1.8.2 and a 1.9 CVS version.  In both it calls
> E> the finalizer when GC is disabled (GC.enable==true).  I thought
> E> this would be impossible.  I also get a recycled object error.
>
> it's normal : the finalizer is called when ruby stop and it don't care at
> this moment if the GC is enabled or not.

They can be invoked before termination of Ruby.  But it's guaranteed that 
all finalizers are called before exit.

> E> Any clues to what is going on with this GC stuff.  If I can't
> E> get this to work, I don't see how anybody reliably use
> E> ObjectSpace._id2ref.
>
> it's best to don't use _id2ref

I beg to differ: you can safely use _id2ref in conjunction with finalizers - 
it just has to be done properly.  It will go wrong - as demonstrated - if 
the same collection that stores ids is used for iterating / querying.

This approach works ok - you'll have to imagine that x contains information 
needed for proper cleanup of a Foo instance, for example, an open IO 
instance (although I'm sure that will do proper cleanup on finalization):

class Foo
  FOOS = {}

  def initialize(x)
    self.x=x

    ObjectSpace.define_finalizer(self) do |oid|
       puts "Cleanup of #{oid} with #{FOOS[oid]}"
    end
  end

  def x=(y)
    @x = y
    FOOS[object_id] = y
  end

  def x() @x end
end

Kind regards

    robert