Am 27.06.2013 um 01:07 schrieb Paul DeBruicker <pdebruic@gmail.com>:
Sven & Camillo,
Ok thanks. And using the PointerFinder is there a way to know which of the pointers points to the SystemDictionary or Object someObject or whereever the GC begins so one would not have to check every pointer for every stubborn object.
E.g. Lets say I've nil'ed the reference between the Navy and the ship so its ready to go but a few of the soldiers on the ship have references to other ships because their transfer papers weren't processed properly. Running #pointersTo on those soldiers gives a large collection of pointers.
How can I use the computer to filter that list to just those references back to the root object?
One by one. You only get the list of objects holding a pointer to the object in question. Having those objects you would need to search for pointers other objects have to them. While trying to analyze the situation it might be a good idea to do a "Smalltalk garbageCollect" in between to get rid of the objects that aren't connected but haven't garbage collected yet. Norbert
Thanks for you help
Paul
On 06/26/2013 03:37 PM, Sven Van Caekenberghe wrote:
Paul,
On 26 Jun 2013, at 23:47, Paul DeBruicker <pdebruic@gmail.com> wrote:
Lets say I'm modeling a navy that is comprised of many ships each with their own soldiers and jobs. If I want one of the ships to be GC'd do I need to implement #release in the soldier and job objects and send it to each of those soldiers and jobs that live and work on the ship I want GC'd or is removing the references between the ship and the navy enough to have the whole ship (including its soldiers and jobs) GC'd?
GC is automatic memory management. Whenever something is no longer reachable by following pointers from a a know starting set, the system dictionary, the stack and some other places, it automatically becomes garbage and the memory it occupies will be reused.
Of course, if you keep a reference to an object, on purpose or by accident, the object will never become garbage and it will keep on occupying memory. Especially circular references can be hard to track.
There are indeed a couple of common messages that are sometimes used to break possible references by nilling out instance variables etc. #close, #stop, #unregister and indeed #release. Often, these are also used to manage external resources (open files, sockets â¦). You can use any message to do this, there is no framework that you have to follow.
And then there are also finalization and weak references, which are related, but more advanced.
Sven