Jens Gustedt - Modern C

The C programming language has been around for a long time the canonical reference for it is the book written by its creators, Kernighan and Ritchie []. Since then, C has been used in an incredible number of applications. Programs and systems written in C are all around us: in personal computers, phones, cameras, set-top boxes, refrigerators, cars, mainframes, satellites ... basically in any modern device that has a programmable interface.

In contrast to the ubiquitous presence of C programs and systems, good knowledge of and about C is much more scarce. Even experienced C programmers often appear to be stuck in some degree of self-inflicted ignorance about the modern evolution of the C language. A likely reason for this is that C is seen as an easy to learn language, allowing a programmer with little experience to quickly write or copy snippets of code that at least appear to do what its supposed to. In a way, C fails to motivate its users to climb to higher levels of knowledge.

This book is intended to change that general attitude, so it is organized in levels that reflect familiarity with the C language and programming in general. This structure may go against some habits of the books readers; in particular, it splits some difficult subjects (such as pointers) across levels in order to not swamp readers too early with the wrong information. Well explain the books organization in more detail shortly.

Generally, although many universally applicable ideas will be presented, that would also be valid for other programming languages (such as Java, Python, Ruby, C#, or C++) the book primarily addresses concepts and practices that are unique to C or are of particular value when programming in the C language.

As the title of this book suggests, todays C is not the same language as the one originally designed by its creators, Kernighan and Ritchie (usually referred to as K&R C). In particular, it has undergone an important standardization and extension process, now driven by ISO, the International Standards Organization. This led to the publication of a series of C standards in 1989, 1999, 2011, and 2018, commonly referred to as C89, C99, C11, and C17. The C standards committee puts a lot of effort into guaranteeing backward compatibility such that code written for earlier versions of the language, say C89, should compile to a semantically equivalent executable with a compiler that implements a newer version. Unfortunately, this backward compatibility has had the unwanted side effect of not motivating projects that could benefit greatly from the new features to update their code base.

In this book, we will mainly refer to C17, as defined in JTC1/SC22/WG14 [.

Programming has become a very important cultural and economic activity, and C remains an important element in the programming world. As in all human activities, progress in C is driven by many factors: corporate or individual interest, politics, beauty, logic, luck, ignorance, selfishness, ego, sectarianism (add your primary motivation here). Thus the development of C has not been and cannot be ideal. It has flaws and artifacts that can only be understood with their historical and societal context.