Hi matz,

a long time ago I remember you have teached me the usage of
ObjectSpace._id2ref within finalizer. Perhaps you remember, it had to
do with my filelock module? The message was from:

   Mon, 14 Dec 1998 12:37:39 +0900

with Subject:

   Re: Next trial: filelock.rb

Here you had proposed to me:

> So, you can get the object reference in finalization routine.
> 
> 	def LockedFile.cleanup()
> 	   lambda do |id|
> 	      obj = ObjectSpace::_id2ref(id)
> 	      ...
> 	   end
> 	end
> 
> But, DO NOT EXPORT the object reference out of finalizer.  It will
> cause serious problem in collecting garbages.

Now I want to implement a finalization module as a look-what's-worth
attempt. Here I want to use exactly this trick. In detail I want to
do:

  :
  Finalizer = proc do |id|
    if FinalizeClients.key? id
      ObjectSpace::_id2ref(id).send(:finalize)
      FinalizeClients.delete(id)
    end
  end
  :

Up to Ruby-1.2 it should have worked, here the code of _id2ref has
contained a piece of:

    :
    if (RANY(ptr)->as.free.flag == 0) {
	IndexError("0x%x is recycled object", ptr);
    }
    :

But since Ruby-1.3.x the code was changed to:

    :
    if (BUILTIN_TYPE(ptr) == 0) {
        rb_raise(rb_eIndexError, "0x%x is recycled object", ptr);
    }
    :

The changelog say: 

Wed Jan  6 02:42:08 1999  Yukihiro Matsumoto  <matz / netlab.co.jp>

        :
	* gc.c (id2ref): modified to support performance patch.
        :

Now this trick would not any longer work. If I try to use _if2ref as
intended in my example above, an IndexError would be thrown.

My question now: Is it possible to return to the old behavior? What i
try to do in deatail is, that every instance could announce itself to
the finalizer that would call the instance's 'finalize' method during
finalization. But I need that _id2ref trick therefore.

Ciao,
\cle

-- 
Clemens Hintze  mailto: c.hintze / gmx.net