Passing Around Borrowed Data

Rust's rules for references might best be summarized by:

• Rust only allows there to be one mutable reference or multiple non-mutable references but not both.
• A reference must never live longer than its owner.

This doesn't tend to be a problem when passing around references to functions.

Memory details:

• The first rule of references prevents data races. What's a data race? A data race when reading from data has the possibility of being out of sync due to the existence of a writer to the data at the same time. This happens often in multi-threaded programming.
• The second rule of references prevents the misuse of references that refer to non-existent data (called dangling pointers in C).