# Crate stable_deref_trait

source ·
Expand description

This module defines an unsafe marker trait, StableDeref, for container types that deref to a fixed address which is valid even when the containing type is moved. For example, Box, Vec, Rc, Arc and String implement this trait. Additionally, it defines CloneStableDeref for types like Rc where clones deref to the same address.

It is intended to be used by crates such as owning_ref and rental, as well as library authors who wish to make their code interoperable with such crates. For example, if you write a custom Vec type, you can implement StableDeref, and then users will be able to use your custom type together with owning_ref and rental.

no_std support can be enabled by disabling default features (specifically “std”). In this case, the trait will not be implemented for the std types mentioned above, but you can still use it for your own types.

## Traits

- CloneStableDeref
  An unsafe marker trait for types where clones deref to the same address. This has all the requirements of StableDeref, and additionally requires that after calling clone(), both the old and new value deref to the same address. For example, Rc and Arc implement CloneStableDeref, but Box and Vec do not.
- StableDeref
  An unsafe marker trait for types that deref to a stable address, even when moved. For example, this is implemented by Box, Vec, Rc, Arc and String, among others. Even when a Box is moved, the underlying storage remains at a fixed location.