3.4. Smart pointers and reference counting

In the previous section, we learned the tools to push memory management to the next level. We already saw how we can write types that manage memory efficiently for us while providing much more safety compared to full manual memory management. In this section we will learn that there is a whole zoo of types which handle memory management. These types are part of the C++ and Rust standard libraries, and understanding them will help us in writing better systems code. We will cover the following topics:

• Slices
• Pointers to single objects in C++
• A Rust smart pointer for single ownership: Box<T>
• Moving beyond single ownership
• A reference-counting smart pointer in Rust: Rc<T>
• Implementing Rc<T> in Rust
• The limits of reference counting
• Summary