Chapter 2: Basics

In this chapter we’ll cover the FFI foundations: what FFI is, how we use it to interoperate between C and Rust, and the common pitfalls.

We start with the mechanics of declaring and exporting functions, then work through the kinds of data that cross the boundary: primitive types, structs, enums and unions, slices, and opaque handles. Next we look at why hand-written bindings drift out of sync with the C they describe, and at the tools that generate them for you: bindgen for Rust bindings to C, and cheadergen for C headers from Rust. The chapter ends with the rules we follow to make an FFI boundary trustworthy: validating everything that comes in, and designing an API that is small and documented well enough to keep correct.

Exercises

The exercises for this chapter are located in exercises/02_basics.

Exercise

The exercise for this section is located in 02_basics/00_README