Pinning

Category: Async · Status: stub · Lessons: chapter 06, Async (planned)

One line: Rust's guarantee that a value will not move in memory, needed because an async state machine may hold pointers into itself.

Also called: Pin, Unpin.

How it connects

• See also: Async functions as state machines

In each language

Rust	Pin ↗ keeps a pointee from being moved unless it implements Unpin
C#	a different pinning: fixed ↗ stops the garbage collector from relocating a variable while a pointer to it is in use, and so does a Pinned ↗ GCHandle

Where to read more

• In the books: Asynchronous Programming in Rust, Carl Fredrik Samson — ch. 9, 'Coroutines, Self-Referential Structs, and Pinning'
• In the books: Programming Rust, Jim Blandy, Jason Orendorff, Leonora F. S. Tindall — ch. 20, 'Asynchronous Programming' → 'Pinning'
• Reference: Rust std: module pin ↗