The Objective-C Runtime is one of the overlooked features of Objective-C initially when people are generally introduced to Cocoa/Objective-C. The reason for this is that while Objective-C (the language) is easy to pick up in only a couple hours, newcomers to Cocoa spend most of their time wrapping their heads around the Cocoa Framework and adjusting to how it works. However the runtime is something that everybody should at least know how it works in some detail beyond knowing that code like [target doMethodWith:var1]; gets translated into objc_msgSend(target,@selector(doMethodWith:),var1); by the compiler. Knowing what the Objective-C runtime is doing will help you gain a much deeper understanding of Objective-C itself and how your app is run. I think Mac/iPhone Developers will gain something from this, regardless of your level of experience.
On Apple Devices by Joachim Bengtsson 0 Introduction In Mac OS X 10.6, Apple introduced a syntax and runtime for using blocks (more commonly known as closures) in C and Objective-C.
One thing that developers who are new to Objective-C will notice immediately are the number of null keywords. We have a choice of: Under the hood there isn’t much difference between these (as of this writing they are all defined exactly the same way), but by convention they have some subtle variations, and they have some odd behavior around them that it pays to understand. All three of these values represent null, or zero pointer, values.
Author: Drew McCormack Web Sites: www.mentalfaculty.com Last week, Chris Lattner — who manages the Clang, LLVM, and GCC groups at Apple — announced that work was well underway to bring ‘blocks’ to the GCC and Clang compilers. ‘So what?’