Re: Reuse of userdata?

["Adam D. Moss" <adam@...>]

Mark Hamburg wrote:
> on 1/9/04 4:39 PM, Adam D. Moss at adam@gimp.org wrote:
> > If you create a new reference to the object within the __gc
> > callback then the object will safely survive the GC.
>
> I hadn't realized that Lua supported resurrection. That's potentially good
> from an allocation speed standpoint and bad from the standpoint that it
> makes the semantics more complicated. Is the resurrected object eligible for
> repeat finalization?

Now I'm not so sure that what I said is right (though it's
not necessarily wrong :)) -- I just checked the only place
in my code where I need resurrection, and I'm doing a shallow
copy of the object's attributes into a new object with a new dtor,
instead of simply making a new ref.  I don't know if simply taking
a new *local* ref (ie. one that doesn't outlive the running of the
dtor function) still causes the object to be collected (I would
expect so), but a longer-living one should cause the object to
continue to live.  The GC might re-fire -- it doesn't for me, but
that might be because of the additional semantics my class system
adds for dtors which doesn't really take trivial resurrection into
account.

--Adam
--
Adam D. Moss   . ,,^^   adam@gimp.org   http://www.foxbox.org/   co:3