Objective-C

Chapter 4. Understanding Objective-C Memory Management

In This Chapter

• Introducing memory management

• Using reference counting

• Building objects that manage memory

• Using garbage collection

• Converting existing code to garbage collection

• Knowing what memory management model to use

One of the biggest challenges you may face as a new Objective-C developer when coming to the platform from other languages, such as Java, Ruby, and Python, is that Objective-C requires that you think about memory management. Many other modern languages have built-in memory management systems (garbage collection, for example) which enable the programmer to ignore most memory management concerns. Objective-C has a garbage collected runtime version, but it is relatively new to the language and unavailable when working on some of the platforms that Objective-C runs on, such as iPhone and iPad. As a result, while it would be nice to say that a new Objective-C developer has no need to be concerned about memory management, doing so would be a disservice to you as a new student of Objective-C. It is entirely likely that even if you are not writing Objective-C code for platforms other than MacOS X, you will still run into MacOS X code, which does not have garbage collection and requires you to manage your memory manually.

Fortunately, however, if you become familiar with the Objective-C memory management rules, even managing your memory by hand can be a reasonably simple affair. By the time you finish this chapter, you should ...