Chapter 1: Unsafe Rust foundations

Safe Rust comes with a guarantee: if the program compiles, it has no undefined behavior. The compiler enforces the rules for references, valid values, and mutation that make that guarantee possible. Those checks stop at the language boundary, though. Rust cannot borrow-check C, and C does not enforce Rust’s invariants. It falls to you to know what each language guarantees about memory, what it assumes, and what happens when those assumptions don’t hold.

This chapter covers the building blocks: what unsafe means and what it does and doesn’t change, how raw pointers differ from references, how NonNull and Option let the type system track null pointers, and how size, alignment, and padding work.

Exercises

The exercises for this chapter are located in exercises/01_foundations.

Exercise

The exercise for this section is located in 01_foundations/00_README