[Python-3000] PEP: Eliminate __del__

Greg Ewing greg.ewing at canterbury.ac.nz
Fri May 4 06:08:59 CEST 2007

Giovanni Bajo wrote:
> On 01/05/2007 18.09, Phillip J. Eby wrote:
> > That means that if 'self' in your example above is collected, then 
> > the weakref no longer exists, so the closedown won't be called.
> Yes, but as far as I understand it, the GC does special care to ensure that 
> the callback of a weakref that is *not* part of a cyclic trash being collected 
> is always called.

It has nothing to do with cyclic GC. The point is that
if the refcount of a weak reference drops to zero before
that of the object being weakly referenced, the weak
reference object itself is deallocated and its callback
is *not* called. So having the resource-using object
hold the weak ref to the resource doesn't work -- it
has to be kept in some kind of separate registry.


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