Changes

In Rust, some data types are defined as “thread safe” while others are not. For example, Rc<T> type, which is Rust’s own implementation of “smart pointer”, is considered to be unsafe to share across threads. This type keeps track of number of references and increments/decrements count each time a new reference is created or old one gets destroyed. Rc<T> does not enforce any mechanisms that make makes sure that changes to the reference counter value can’t be interrupted by another thread. The snippet below demonstrates the issue an results in compiler error:

This time the code worked. This example was very simple and not too impressive. Much more complicated algorithms can be implemented with the Mutex<T>.