Rust for Rustaceans

9 Unsafe Code

The mere mention of unsafe code often elicits strong responses from many in the Rust community, and from many of those watching Rust from the sidelines. While some maintain it’s “no big deal,” others decry it as “the reason all of Rust’s promises are a lie.” In this chapter, I hope to pull back the curtain a bit to explain what unsafe is, what it isn’t, and how you should go about using it safely. At the time of writing, and likely also when you read this, Rust’s precise requirements for unsafe code are still being determined, and even if they were all nailed down, the complete description would be beyond the scope of this ...