To use Objective-C effectively, it is important to understand the basic infrastructure of the language. The compiler plays a special role in the software development cycle, since it determines how source code is translated into executable programs. In the Apple environment, two main compilers are employed: gcc, the traditional compiler used by Mac OS X, and the new clang compiler based on LLVM (Lower Level Virtual Machine), which has been developed as an open source project by Apple and others during the last few years.
The compiler is responsible for translating your program into binary instructions that will be directly executed by the CPU. Every source file has to be processed first, but when it comes time to ...