Re: Life of instance variables?

[Albert Chun-Chieh Huang]

Albert Chun-Chieh Huang <jjhuang@cm.nctu.edu.tw> writes:

> Dear all,
>     My question is about instance variable. Let me explain in details:
> Node and MyNode is two classes, their relationship is 
> MyNode : Node : NSObject, where MyNode is a subclass of Node.
> In my code, there is only instances of MyNode, for Node is an abstract
> class. 
[stuff deleted]

Sorry, I found an interesting thing. I add some NSLog to Node class to
print out [[self description] cString]. I found the memory location
changes every time. And after tracing the bug, I found that I made a
BIG mistake. I forgot that, in NSMutableDictionary, key will be
*copied* while I thought it was *retained*. I used NSMutableDictionary
to record Nodes which is ready to receive packets as a key. After
finding this, I've corrected my code. I don't use Node as a key for
the dictionary now. I use it as a value, and it works as expected now. 

Sorry, I always looked up Foundation classes in OpenStep specification
on October 19, 1994. And it doesn't mention this. I searched documents
on GNUstep.org. Finally, I found some documents about this.

Thanks for helps.

Best Regards,
Albert
-- 
Chun-Chieh Huang, aka Albert   | E-mail: jjhuang AT cm.nctu.edu.tw
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