OK, The bigger picture. Here goes ...

It basically has to do with circular references.
To deal with them we could use Scalar::Util::weaken or just cleanup the objects manually.
Scalar::Util::weaken won't work for me because the code often refers to a "parent" object via a "child" and vice-versa. I'll illustrate:

sub circ_ref {
    my $dad = {};
    my $son = {};
    $dad->{son} = $son;
    $son->{dad} = $dad;

    Scalar::Util::weaken $son->{dad};

    return $dad;
}

my $dad = circ_ref();        # All is well
my $son = circ_ref()->{son}; # Doh! Who's your daddy?

print Data::Dumper::Dumper $dad, $son;

[download]

So instead I have to cleanup the objects manually, but at what point? The references to either "parent" or "child" may hang around for while. Only when they have both gone can I cleanup the circ-ref. To do this I need to know when the REFCNTs have dropped to 1.

So I was trying to find a way to "hook" SvREFCNT_dec for these objects, but I guess this is just not possible.
Is there another way to do the cleanup?

In reply to Re: Intercept any changes to the sv_refcnt/SvREFCNT of an object by vernonlyon
in thread Intercept any changes to the sv_refcnt/SvREFCNT of an object by vernonlyon

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