Advice needed on __del__

[Fredrik Lundh]

"phil" wrote:

> > Python makes no guarantees whatsover about when and how to
> > run __del__, so relying on it to remove user-visible resources is a
> > rather bad idea.

> What does that mean?  Is it a destructor or not?

it's a finalizer.

most Python implementations do a reasonable attempt to call finalizers
on all objects, sooner or later, but it's not guaranteed by the language
specification:

    "It is not guaranteed that __del__() methods are called for
    objects that still exist when the interpreter exits."

> I create thousands of instances of objects in a geometry
> instruction program and rely heavliy on __del__ to do its
> thing.  For instance when I am rotating objects, I delete and
> recreate somtimes hundreds of times. Works so far.

why do you rely on __del__ to remove your objects?  why not just
leave that to the garbage collector?

(__del__ disables cycle detection, so a program that uses __del__
carelessly is more likely to leak memory than a program that doesn't
use it at all).

> 2. If Python is an oop language, meaning instances of classes
>      are essential, then a reliable destructor method is essential.

Python is not C++.

</F>