On Wed, Jan 7, 2009 at 11:42 AM, Eric Snow <es...@verio.net> wrote:
> I was reading in the documentation about __del__ and have a couple of
> questions. Here is what I was looking at:
>
> http://docs.python.org/reference/datamodel.html#object.__del__
>
> My second question is about the following:
>
> "It is not guaranteed that __del__() methods are called for objects
> that still exist when the interpreter exits."
>
> I understand that and have seen it too. That's fine. But how do any
> of you deal with things that are left open because you did not get a
> chance to close them? How do you clean up after the fact? Do you
> simply keep track externally the things that need to be cleaned up if
> __del__ doesn't get a chance? Any ideas? Thanks
As you point out, __del__ is not a reliable way to free limited
resources. Instead, one generally includes logic to explicitly free
the resources. This is generally done using try-finally or the `with`
statement.
Example:
def mess_with_file(f):
try:
#fiddle with the file
finally:
f.close() #guarantee that the file gets closed
def mess_with_other_file(filename):
with open(filename) as f:
#do stuff with file
x = None #the file has now been closed, and it'll be closed even
if an exception gets raised
#the "context handler" (see PEP 343) for the `file` type
guarantees this for us
Cheers,
Chris
--
Follow the path of the Iguana...
http://rebertia.com
--
http://mail.python.org/mailman/listinfo/python-list
