Memory Management question about sample iPhone app code CoreDataBooks

[mebarron]

I have a memory management question about sample iPhone app code from Apple, namely:
--------
CoreDataBooks:RootViewController.m

line 255 : // Release the adding managed object context.
line 256 : self.addingManagedObjectContext = nil;
--------

at line #256 the retainCount for addingManagedObjectContext == 1

shouldn't line #256 be the following:

[[self addingManagedObjectContext] release];

Otherwise there is a memory leak, Right?

[BrianSlick]

See the properties link in my signature for more information.

[dda]

Originally Posted by mebarron

I have a memory management question about sample iPhone app code from Apple, namely:
--------
CoreDataBooks:RootViewController.m

line 255 : // Release the adding managed object context.
line 256 : self.addingManagedObjectContext = nil;
--------

at line #256 the retainCount for addingManagedObjectContext == 1

shouldn't line #256 be the following:

[[self addingManagedObjectContext] release];

Otherwise there is a memory leak, Right?

No. addingManagedObjectContext is an instance variable that is released in the dealloc method of the class it's part of.

Regards,

DDA

[mebarron]

Originally Posted by dda

No. addingManagedObjectContext is an instance variable that is released in the dealloc method of the class it's part of.

Regards,

DDA

Thanks so much for your reply.
Please help me out here. As I see it

line 255 : // Release the adding managed object context.
line 256 : self.addingManagedObjectContext = nil;

just prior to execution of line 255 and just after it too,
the retainCount == 1 on the object pointed to by addManagedObjectContext.

The command in the method dealloc would be:

[addingManagedObjectContext release];

This would result in the decrementation of the retainCount from 1 to zero
for the object pointed to by the variable:

addingManagedObjectContext .

Problem is, this variable/pointer has been set to nil
and the object that it used to point to is still sitting
in memory with a retainCount == 1 . Or ?

Furthermore, I don't see, any check for

if(addingManagedObjectContext == nil)

in the code, to use it as a flag. Please let me
know if I am missing something.

[BrianSlick]

What you are missing is a good read of my properties thread. Go read it.

And you can't rely on retainCount, particularly if the object should be gone.

[mebarron]

Originally Posted by BrianSlick

What you are missing is a good read of my properties thread. Go read it.

And you can't rely on retainCount, particularly if the object should be gone.

Thanks so much for taking the time. Thanks for the heads up about your
fine properties page. I had never before seen code for a setter such
as produces by @synthesize. I assumed that the retain/release protocol
had to be coded if you wanted it. All is clear now.

- (void)setMyArrayInstanceVariable: (NSArray *)anArray
{
[myArrayInstanceVariable release];
[anArray retain];
myArrayInstanceVariable = anArray;
}