Re: NSWindowController subclasses, and retain cycles
Re: NSWindowController subclasses, and retain cycles
- Subject: Re: NSWindowController subclasses, and retain cycles
- From: Jonathan Taylor <email@hidden>
- Date: Thu, 24 May 2012 16:52:57 +0100
On 24 May 2012, at 16:27, Kyle Sluder wrote:
>> 1. If I do not set B's pointer to A, both A and B are deallocated correctly
>> 2. If instead I set B's pointer to A, but reset it to nil just before B is closed, both A and B are deallocated correctly
>> 3. If instead B still has a live pointer to A when B is closed, this should be autoreleased by the runtime, which it is. However, A never gets deallocated.
>
> If A somehow has a chain of retains that keeps B alive, #3 is wrong. Your approach with #2 seems sensible.
Thankyou all three for your replies. [I am not using ARC as this must run on Snow Leopard, incidentally].
Having done some playing around with trivial test cases, it appears that I have completely misunderstood a basic concept of properties - apologies for wasting your time. I had always thought that if I declare a property as follows:
@property (retain) MyProgressWindow * progressObject;
...
@synthesize progressObject = _progressObject;
then if that property has a non-nil value at the point that the instance is deallocated, a release would be sent. That had always struck me as the "obvious" behaviour, but it appears that this does not happen. I am sure there is a good reason for that! Not sure how I have managed to go this long without spotting that I am wrong here. Seems a bit of a pain to have to go through setting everything to nil in the dealloc method (which I would otherwise not have to even implement at all in many cases), but looks like that's what I need to do...
Cheers
Jonny
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