On Jan 7, 1:03 pm, Eric Snow <es...@verio.net> wrote: > On Jan 7, 12:57 pm, "Chris Rebert" <c...@rebertia.com> wrote: > > > > > 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 > > Thanks for the responses. What I mean is when a python process is > interrupted and does not get a chance to clean everything up then what > is a good way to do so? For instance, I have a script that uses child > ptys to facilitate ssh connections (I'm using pxssh). When I ^C the > python process I am left with the child processes running and the ssh > connections open. Naturally I run out of ttys if this happens too > much, which I have had happen. So if python does not get a chance to > take care of those, what is a good way to do so? Does a try/finally > or a with statement address that? Thanks! > > -eric
pxssh uses pexpect which uses pty.fork -- http://mail.python.org/mailman/listinfo/python-list
