Re: Circular references not being cleaned up by Py_Finalize()
blackpawn [EMAIL PROTECTED] writes: I know the garbage collector is tracking the object because it properly calls the traverse function but for whatever reason it never calls the clear function. Does anyone have experience with circular references and had success with it or the example in the docs? I've now tried it, and it seems to work. Modifying Nody_dealloc with printf(collecting %p\n, self), it works like this: import noddy4 n = noddy4.Noddy() n.first = n del n # n would be dealloced here without the cycle ^D collecting 0xb7d3bf2c So the garbage-collector is invoked at least once before shutdown. However, it doesn't work without del n line, so it would appear that the gc is not invoked after the module cleanup and therefore doesn't explicitly dealloc global objects that contain cycles. You can work around that by using the atexit module to register a cleanup function that removes your global objects from the module namespace(s) and, if necessary, invokes gc.collect() manually. That way your objects end up as reclaimable garbage. This won't work if your cycle-containing objects are indirectly reachable from the module namespace through other containers not under your control. In that case, you should really rethink your strategy of depending on finalizers to run and perhaps use atexit to do your exit processing or, as others pointed out, use scope tools (try/finally, with) at the entry point of your code. -- http://mail.python.org/mailman/listinfo/python-list
Re: Circular references not being cleaned up by Py_Finalize()
On Tue, 25 Mar 2008 12:32:17 -0700, blackpawn wrote: So what's the deal here? :) I want all objects to be freed when I shut down and their destruction functions to be properly called. Then you want something that's not guaranteed by the language. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: Circular references not being cleaned up by Py_Finalize()
blackpawn schrieb: So what's the deal here? :) I want all objects to be freed when I shut down and their destruction functions to be properly called. Is there really no way to make this happen? Does the Noddy example use GC (Py_TPFLAGS_HAVE_GC)? Container objects must use the cycle GC or circular referneces aren't broken. Have you tried calling PyGC_Collect() multiple times? Christian -- http://mail.python.org/mailman/listinfo/python-list
Re: Circular references not being cleaned up by Py_Finalize()
On Mar 25, 2:32 pm, blackpawn [EMAIL PROTECTED] wrote: I've been trying to get garbage collection of circular references to work properly with no success then I noticed the documentation stating that it just doesn't: From documentation on Py_Finalize() - Memory tied up in circular references between objects is not freed. I copy pasted the Noddy example for circular reference breaking from the documentation and set a break point in its Noddy_dealloc function and sure enough even that simple example doesn't work properly. So what's the deal here? :) I want all objects to be freed when I shut down and their destruction functions to be properly called. Is there really no way to make this happen? Many thanks for any insights, Jim It sounds like you are using finalizers like destructors in C++. Don't do this. Garbage collection is not deterministic, and is not supposed to be. Instead, use language features that do similar scope-driven code execution: - try/except/finally - with Put your cleanup code in the finally block, or in the context managers __exit__ method. These will run when the program exits the given scope, without having to play GC shenanigans. -- Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Circular references not being cleaned up by Py_Finalize()
Does the Noddy example use GC (Py_TPFLAGS_HAVE_GC)? Container objects must use the cycle GC or circular referneces aren't broken. Have you tried calling PyGC_Collect() multiple times? Yeah the Noddy example is from 2.1.3 Supporting cyclic garbage collection part of the Python docs. They list sample C and Python code which I cut and pasted with no changes and on Py_Finalize and app shut down it leaks the object. I know the garbage collector is tracking the object because it properly calls the traverse function but for whatever reason it never calls the clear function. Does anyone have experience with circular references and had success with it or the example in the docs? -- http://mail.python.org/mailman/listinfo/python-list
