m02-resource

Use Box for single-thread exclusive ownership, Rc for single-thread shared ownership, and Arc for multi-thread shared ownership. The correct smart pointer strategy depends on whether your Rust program requires thread-safe reference counting across concurrency boundaries.

Avoid reference cycles by pairing Rc or Arc with Weak pointers to break strong reference cycles. Guardrailed patterns prevent runtime panics by ensuring safe lifetime management and proper usage of RefCell and Mutex for interior mutability.

For interior mutability, use Cell or RefCell in single-thread contexts and Mutex or RwLock in multi-thread contexts. Selecting the correct concurrency primitive ensures safe mutation without data races across your ownership boundaries.

Yes, this guidance covers lifecycle management by enforcing concrete rules for lifetime management across typical codebases. It helps select safe ownership and pointer strategies that align data lifetimes with single-thread and multi-thread concurrency requirements.

Rc causes compile errors in multi-threaded contexts because it lacks thread-safety guarantees. You must use Arc for multi-thread shared ownership, as Arc provides safe reference counting across threads whereas Rc is restricted to single-thread scenarios.