Resource cleanup

[Robin Becker]

I'm thinking of using Tim Peters' excellent approach to resource clean 
up see

http://mail.python.org/pipermail/python-dev/2006-April/063425.html

> class _RealTypeResourceCleaner:
>     def __init__(self, *resources):
>         self.resources = resources
> 
>     def __del__(self):
>         if self.resources is not None:
>             for r in self.resources:
>                 r.close()
>             self.resources = None
> 
>     # and typically no other methods are needed, or desirable, in
>     # this helper class
> 
> class RealType:
>     def __init__(*args):
>         ...
>         # and then, e.g.,
>         self.cleaner = _ResourceCleaner(resource1, resource2)

but am wondering exactly what 'resources' are left available when the 
r.close method is called in the __del__ method of  RealTypeResourceCleaner.

In particular, can I rely on the module globals of r still being present 
if the RealType instance is going away because the main script has 
terminated, ie if the r.close method refers to a global function is it 
guaranteed to be available when the close is called?

I guess I must be asking if referring to a global in a method is 
actually a reference to that global or does the reference only occur 
when the code is executed?

I have a vague feeling that I came across problems in the past about the 
order in which modules were finalized.
-- 
Robin Becker