memory management and instance variables?

Question

Usually when I create an object and assign it to an instance variable I alloc a temp object, call the iVar setter to retain the object and then release the temp object. However I was looking at init this morning and noticed that if I simply assign the iVar directly, its retained by the alloc whilst also being released correctly when either the setter is called or dealloc is executed. I am just curious if I am understand this correctly?

@property(nonatomic, retain) CLLocationManager *locationManager;

.

@synthesize locationManager;

// VERSION 001
- (id)init {
    self = [super init];
    if(self) {
        CLLocationManager *tempManager = [[CLLocationManager alloc] init];
        [self setLocationManager:tempManager];
        [tempManager release];  
    }
    return self;
}

// VERSION 002
- (id)init {
    self = [super init];
    if(self) {
        locationManager = [[CLLocationManager alloc] init]; 
    }
    return self;
}

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

score 2 · Answer 1 · edited May 23 '17 at 10:33

2

As far as the memory management goes both solutions are fine. But you might want to prefer the direct access in init and dealloc, see this related question.

edited May 23 '17 at 10:33

Community

1
1

answered Nov 25 '10 at 15:13

zoul

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I was aware of not using setters in dealloc from a previous question, its good to know that I should not be using them in init as well. So would I be right in saying that for init & delloc directly assign the iVars like v_002. For other methods its best to go with alloc object, use the setter to assign the iVar & finally release the object. – fuzzygoat Nov 25 '10 at 15:34

score 1 · Accepted Answer · answered Nov 25 '10 at 16:22

Version 002 is the Apple approved answer because the pitfalls of using an accessor in init are theoretically worse. Basically, a subclass could choose to override your accessor and then you'd be sending a message to a subclass object that is not yet initialised.

However, everywhere else except init and dealloc, use version 001.

memory management and instance variables?

2 Answers2