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



 

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