Question

Over the time that I’ve been on StackOverflow, I’ve noticed that some users post their code with all of the releases still there although releasing is deprecated. By releasing, I mean something along the lines of:

[self.data release];

Why do users still do this? I know nothing about programming for older versions of iOS, and would love to do so, but when I try to release something in an app I’m building, I get either a deprecation error, or a warning. If what I just said is correct, how do I program for older versions? Also, how do I prevent these errors?

Answer 1

Well, bit of a broad question, and the straight forward answer is: go and read the documentation.

From documentation advanced memory management

Objective-C provides two methods of application memory management.

1) In the method described in this guide, referred to as “manual
retain-release” or MRR, you explicitly manage memory by keeping track
of objects you own. This is implemented using a model, known as
reference counting, that the Foundation class NSObject provides in
conjunction with the runtime environment.

2) In Automatic Reference Counting, or ARC, the system uses the same
reference counting system as MRR, but it inserts the appropriate
memory management method calls for you at compile-time. You are
strongly encouraged to use ARC for new projects. If you use ARC, there
is typically no need to understand the underlying implementation
described in this document, although it may in some situations be
helpful. For more about ARC, see Transitioning to ARC Release Notes.

Well, you are using the second method, but in those olden days programmers used manual- retain-release.. And some old school people (count me as one) still uses them..

The transition to ARC release notes will walk through this transition..

EDIT: some additions (first posted as comment, but thought better add it in answer..)

If you started first at ARC, then that is the way to go. Manual reference counting is difficult/confusing at first, but once learned will help you get a deep understanding of how memory is managed at core level (and trust me that will improve your confidence level as a iOS programmer). Remember that what ARC does is automatically adding this retain/release calls at compile time. So retain release calls are still there, it is just that you don’t have to worry about it.

You can be an iOS developer without understanding Manual Retain Release paradigm, but nothing bad (and plenty of good) will happen if you learn them.. Something for you to read at bed time.