What is retainCount in Objective-C?

Question

I have a UITableView as my first screen with a UINavigation controller.

In my first screen I NSLog(@"Home Screen retain Count=%d",[self retainCount]); and it logs 6 in when its viewDidLoad is called.

Is this correct?

Answer 1

The retainCount is the number of ownership claims there are outstanding on the object.

You take ownership of an object if you create it using a method whose name begins with “alloc” or “new” or contains “copy” (for example, alloc, newObject, or mutableCopy), or if you send it a retain message. All of these increment the retainCount.

You relinquish ownership with using “release” or “autorelease”. These decrement the retainCount.

However you should never pay any attention to the value of retainCount, it is at best confusing, at worst misleading. Simply follow the memory management rules - take ownership when you need to keep a reference to an object and relinquish ownership when you are finished, and you wont have a problem.

If you are looking at retainCount, you are going about things the wrong way, and you will simply confuse yourself further.

Answer 2

It sounds fine. Why would it be wrong?

In general, trying to determine things from the retain count is a bad idea. There are no rules about the amount of times you can retain an object. The only rule is that each retain must be balanced with a release.