Release retain property in dealloc?

Question

I have a class with a property defined in the .h file as:

@property (retain) NSString *fontName;

In the .m file I release the property:

-(void)dealloc {
    [super dealloc];
    [_fontName release];
}

Now I'm occasionally getting a EXC_BAD_ACCESS error on [_fontName release]. The occurrence is so rare that I'm not really sure how to debug it. Is is correct to release a @property (retain)? Or does [super dealloc] already do that?

occasionally getting a EXC_BAD_ACCESS because some time you release object name **fontName** that already released. — iPatel, Mar 14 '14 at 10:59

score 6 · Accepted Answer · answered Mar 14 '14 at 10:58

6

Perform the super dealloc AFTER:

-(void)dealloc {
    [_fontName release];
    [super dealloc];
}

In short, kill your children before killing yourself.

answered Mar 14 '14 at 10:58

Cyrille

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Or **Don't cut branches when you are sitting on one of them.*** – Anoop Vaidya Mar 14 '14 at 11:05
Of course! I somehow got into the habit of always putting [super dealloc] first. Not sure why... Anyway, thanks! This should solve my problem. – Bart Mar 14 '14 at 11:17

score 0 · Answer 2 · answered Mar 14 '14 at 11:09

The more traditional approach is to simply release your instance variables and leave them pointing to the released (and potentially deallocated) object, like so:

- (void)dealloc
{

    [_fontName release];

    [super dealloc];
}

In this approach, each of the pointers will be pointing to a potentialy invalid object for a very short period of time — until the method returns — at which point the instance variable will disappear along with its owning object. In a single-threaded application (the pointer would have to be accessed by something triggered by code in either this object's implementation of dealloc or in the dealloc of one of its superclasses, there's very little chance that the instance variables will be used before they go away , which is probably what has led to the proclamations made by several that there's "no value in setting instance variables to nil" in dealloc.

That's why ARC is so awesome. – Cyrille Mar 14 '14 at 12:18 — Cyrille, Mar 14 '14 at 12:18

Release retain property in dealloc?

2 Answers2