Why integration is possible?
As we have explained in Chapter 10, Unix – History and Architecture, C revolutionized the way we were developing operating systems. That's not the only magic of C; it also gave us the power to build other general-purpose programming languages on top of it. Nowadays, we call them higher-level programming languages. The compilers of these languages are mostly written in C and if not, they've been developed by other tools and compilers written in C.
A general-purpose programming language that is not able to use or provide the functionalities of a system is not doing anything at all. You can write things with it, but you cannot execute it on any system. While there could be usages for such a programming language from a theoretical point of view, certainly it is not plausible from an industrial point of view. Therefore, the programming language, especially through its compiler, should be able to produce programs that work. As you know...
