Ace the Rust Interview

Enter your book access code

The curriculum, drills, tutor, and interviewer mode are for readers of Ace the Rust Interview. The code is printed in the Preface (Companion site access).

Don’t have the book yet? The landing page stays open — purchase unlocks this gym.

advanced · order 158

std Mutex across await

async-mutex-01Related book chapters: 24 (optional — this page is complete on its own)tokio-mutex

Slug: async-mutex-01 · Paired reading: Chapter 24

Prompt

Correct pattern: async fn bump(map: Arc<Mutex<i32>>) -> i32 mutates and DROPS the guard before YieldOnce.await. Holding a std MutexGuard across await is !Send and can deadlock the runtime.