ARC - ObjC Objects with CF instance variables

Question

I think I'm being a bone head here...

The static analyzer complains in the -(void)doSomethingInteresting method:

Potential leak of an object stored into myAddressBook

Well, sure, that makes sense; I'm calling a create function without a matching release. But, I don't think I want to release myAddressBook at the end of -doSomethingInteresting because I want it to stick around for the life of the AwesomeObject instance.

AwesomeObject.h

@interface AwesomeObject : NSObject

@property (assign, nonatomic) ABAddressBookRef addressBook;

@end

AwesomeObject.m

@implementation AwesomeObject

- (void)doSomethingInteresting
{
    CFErrorRef error = NULL;
    ABAddressBookRef myAddressBook = ABAddressBookCreateWithOptions(NULL, &error);

    [self setAddressBook:myAddressBook];
}

@end

EDIT: Screen shot attached

Static Analyzer Arrows

the property should retain, then you should release... that way the object is the owner rather than the local scope. — Grady Player
– Grady Player, Commented Mar 14, 2014 at 18:17

Léo Natan · Accepted Answer · 2014-03-14 18:20:36Z

3

The analyzer doesn't understand you wish to assign a retained address book in your property, and thus not release it at the end of doSomethingInteresting.

Change your property to:

@property (strong, nonatomic) id addressBook;

and set it like so:

[self setAddressBook:CFBridgingRelease(addressBook)];

Now, when you want to use the addressBook property, use the (__bridge ABAddressBookRef) cast.

Also, you need to release a potential CFErrorRef object, which may have been created during ABAddressBookCreateWithOptions:

if(error)
{
    CFRelease(error);
    error = NULL;
}

edited Mar 14, 2014 at 18:20

answered Mar 14, 2014 at 18:06

Léo Natan

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Comments

matt · Accepted Answer · 2014-03-14 18:11:05Z

0

You need to call it like this:

 [self setAddressBook:CFBridgingRelease(myAddressBook)];

answered Mar 14, 2014 at 18:11

matt

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12 Comments

matt Over a year ago

And see my book to learn why: apeth.com/iOSBook/ch12.html#_memory_management_of_cftyperefs

matt Over a year ago

It shouldn't be. :) It should be strong as usual (it should be an id), and we just hand it over to ARC to manage until the end of time.

Léo Natan Over a year ago

@matt Yes, I know what it should be, but you should have pointed it in your answer, instead of pointing to your book.

matt Over a year ago

@LeoNatan It's not advertising! It's free tutorial material like any other. I've deliberately put this stuff on the Web to make it public and available for free. That's not bad, it's good.

matt Over a year ago

@LeoNatan and that is what I thought I did. Hey, the marketplace decided - you got several upvotes and the checkmark, why be a bad winner? That's why Stack Overflow is great!

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