Objective C memory leak

Question

Hi all, I want to clarify whether there is a memory leak in this code? As far as I feel its there.

in .h file

@interface MyClass{
     NSMutableArray *dataArray;    
}

@property(nonatomic,retain) NSMutableArray *dataArray;

in .m file

-(id) init{    
    self. dataArray = [[NSMutableArray alloc]init];    
}

-(void) dealloc{   
    [self.dataArray release];
    [super dealloc];
}

Answer 1

Take the self.'s out because those are acting as the getters, it's not like Java or other languages. Otherwise it looks fine.

Answer 2

Yes, there is a leak there.

Should be

self.dataArray = [[[NSMutableArray alloc] init] autorelease];

Since dataArray is defined as a retain property, using self.dataArray on the left-hand side of an assignment implies a retain on the right-hand side.

edit: ...plus a release on the object that had previously been stored in self.dataArray, which is nil at the time of the init call.

Answer 3

Yes, there is a leak in init. dataArray is declared with the retain attribute. So it retains the given array. But since you allocated it you own it and you have to release it afterwards.

Also the dealloc is not good. This code may crash under some circumstances (probably not here) because you release an object you don't own.

Should be something like this:

-(id) init {
    NSMutableArray *array = [NSMutableArray new];
    self.dataArray = array;
    [array release];
}

-(void) dealloc {
    self.dataArray = nil;
    [super dealloc];
}