This Book Is Not Really about C

Please don't feel cheated, but this book is not about teaching you C programming. You'll learn to write programs in C, but the most important lesson you'll get from this book is rigorous defensive programming. Today, too many programmers simply assume that what they write works, but one day it will fail catastrophically. This is especially true if you're the kind of person who has learned mostly modern languages that solve many problems for you. By reading this book and following my exercises, you'll learn how to create software that defends itself from malicious activity and defects.

I'm using C for a very specific reason: C is broken. It is full of design choices that made sense in the 1970s but make zero sense now. Everything from its unrestricted wild use of pointers to its severely broken NUL terminated strings are to blame for nearly all of the security defects that hit C. It's my belief that C is so broken that it's the most difficult language to write securely in wide use today. I would fathom that Assembly Language is actually easier to write securely than C. To be honest, and you'll find out that I'm very honest, I don't think that anybody should be writing new C code.

If that's the case, then why am I teaching you C? Because I want you to become a better, stronger programmer, and there are two reasons why C is an excellent language to learn if you want to get better. First, C's lack of nearly every modern safety feature means you have to be more vigilant and more aware of what's going on. If you can write secure, solid C code, you can write secure, solid code in any programming language. The techniques you learn will translate to every language you use form now on. Secondly, learning C gives you direct access to a mountain of legacy code, and teaches you the base syntax of a large number of descendant languages. Once you learn C, you can more easily learn C++, Java, Objective-C, and JavaScript, and even other languages become easier to learn.

I don't want to scare you away by telling you this, because I plan to make this book incredibly fun, easy, and devious. I'll make it fun to learn C by giving you projects that you might not have done in other programming languages. I'll make this book easy by using my proven pattern of exercises that has you doing C programming and building your skills slowly. I'll make it devious by teaching you how to break and then secure your code so you understand why these issues matter. You'll learn how to cause stack overflows, illegal memory access, and other common flaws that plague C programs so that you know what you're up against.

Getting through this book will be challenging, like all of my books, but when you're done you will be a far better and more confident programmer.