I think that's where you're confused: `Arc` does not do any synchronization, again it's pretty much the same as `std::shared_ptr` (hence the name Arc: Atomically Reference Counted).

Your `Locker` does not do what `Arc` does, even at compile time, because it does not allow concurrent access, like an `Arc<AtomicBool>` would. Your `Locker` is more like an `Arc<RwLock<T>>`.

Best equivalent you can get in C++ is `Arc<T>` = `std::shared_ptr<const T>`.

https://doc.rust-lang.org/std/sync/struct.Arc.html

> Shared references in Rust disallow mutation by default, and Arc is no exception: you cannot generally obtain a mutable reference to something inside an Arc. If you need to mutate through an Arc, use Mutex, RwLock, or one of the Atomic types.

I guess you could get the final pieces to get something similar by creating `Send` and `Sync` traits in C++: https://doc.rust-lang.org/nomicon/send-and-sync.html. I think the main pain point here is that you cannot auto-derive `Send` and `Sync` so it would end up being very verbose.