The SafeC Book

Welcome to The SafeC Book — a from-scratch, worked-example tutorial for learning SafeC as a language, in the tradition of Kernighan & Ritchie's The C Programming Language and The Rust Programming Language. Where those books teach C's small, orthogonal core and Rust's ownership model through running examples rather than dry enumeration, this book does the same for SafeC: a C superset whose one big idea is the region system — compile-time-tracked memory provenance (&stack, &heap, &arena<R>, &static) that catches use-after-free and aliasing bugs before your program ever runs, at zero runtime cost.

This is a tutorial, not a reference. It introduces features in the order you need them to write real programs, with complete, compilable examples at every step — every code block in this book has been compiled and, where it produces output, run, against the real safec compiler. For exhaustive detail on any single feature (every operator's precedence, every stdlib function's signature), see the Reference and Standard Library sections instead — this book will link to them at the point where you're ready for that depth.

Who this book is for

You should already know how to program in some C-family language (C, C++, Java, Go, Rust — the exact one doesn't matter much) and be comfortable with pointers as a concept, even if a specific language kept them out of your hands. This book does not re-teach "what is a variable" or "what is a loop" from first principles the way a total-beginner programming book would — Chapter 3 moves through those quickly, as a refresher of SafeC's specific syntax rather than the underlying concepts. If you know C reasonably well, most of Chapters 1–4 will be fast going; the real new material starts at Chapter 5.

How to read this book

Chapters are meant to be read in order — each one builds on syntax and vocabulary from the ones before it, the same way The Rust Programming Language's chapters do. If you already know C well, Chapter 5 (regions) is the one chapter you shouldn't skip: it's the one genuinely new idea in the whole language, and everything from Chapter 6 onward assumes you have it.

1. Getting Started — installing the toolchain, safeguard new, compiling and running your first program
2. A First Program — a complete temperature-converter CLI tool, introducing I/O and the edit-compile-run loop
3. Common Concepts — variables, types, operators, control flow
4. Functions — declarations, parameters, overloading, pure
5. Understanding Regions — the region system: &stack, &heap, &arena<R>, &static, and the borrow rules
6. Structs and Methods — defining types, methods, operator overloading
7. Enums, Unions, and Match — tagged unions and exhaustive pattern matching
8. Error Handling — optionals, try, defer/errdefer, no exceptions
9. A Final Project: a Key-Value Store — putting it all together in a larger program

Let's get started.