Thanks for the explanation Gordon. I guess I wish there were pointers to pointers in AS3 based on what you described. I wasn't necessarily looking to null out object a in my example, but just carry the pointer along. The following example is closer to what I'm getting at:
var a:Object = new Object(); var b:Object = new Object(); ChangeWatcher.watch(a, ... .... a = b I may set up the ChangeWatcher in one screen but make the change to a in another. Based on what you described how would I make sure that a ChangeWatcher doesn't hold onto the reference? Thanks, Jaime On 1/30/07, Gordon Smith <[EMAIL PROTECTED]> wrote:
It sounds like you're thinking that a = null somehow wipes out the object itself. It doesn't. It simply nulls out the variable 'a', which is a different thing from the object that 'a' refers to. Think of variables like 'a' and 'b' as "pointers" to objects. (Technically, they're 4-byte areas of memory that store the memory address where an object exists.) After executing the first two lines, you have two different pointers pointing to the same object. After executing a = null, the 'a' pointer no longer points to the object but the 'b' pointer still does. So now you might be wondering how you wipe out the object itself. You can't do this directly; only the garbage collector can destroy an object. It is allowed to do so whenever there are no references (pointers) to the object. So you could indirectly wipe out your object by setting both 'a' and 'b' to something else. The object would then become eligible for garbage collection at some indefinite time in the future. - Gordon ------------------------------ *From:* [email protected] [mailto:[EMAIL PROTECTED] *On Behalf Of *Jaime Bermudez *Sent:* Tuesday, January 30, 2007 1:52 PM *To:* [email protected] *Subject:* [flexcoders] AS3 object reference changes? I have a simple question that may be dumb but I find somewhat interesting. I have something similar to the following simplified AS3 code: var a:Object = new Object(); var b:Object = a; a = null; ------------------------------------------- Why does object b hold on to a's object reference? I would expect b to become null. Thanks, Jaime
