What is Objective-C 2.0?
With Mac OS X version 10.5 (“Leopard”), Apple introduced some incremental features to the Objective-C language. These features are being marketed as “Objective-C 2.0” and shall be referred to here as ObjC 2. See the section on ObjC 2 below, or where an answer needs further consideration under ObjC 2 discussion will appear in this font style. Currently ObjC 2 features are only available on the Apple runtime in Mac OS X version 10.5. The new features are entirely “opt-in” and there is no compatibility break with the existing Objective-C language.
With Mac OS X version 10.5 (“Leopard”), Apple introduced some incremental features to the Objective-C language. These features are being marketed as “Objective-C 2.0”. As the features have been in the language for a long time and are available across platforms now, this FAQ makes no distinction between “traditional” and ObjC 2 features.
