Chapter 19: Smart Pointers

Memory management is a critical aspect of systems programming. In C, pointers are raw memory addresses that you manage with functions such as malloc() and free(). In Rust, however, the standard approach centers on stack allocation and compile-time-checked references, ensuring memory safety without explicit manual deallocation. Nevertheless, certain use cases require more flexibility or control over ownership and allocation. That’s where smart pointers come in.

Rust’s smart pointers are specialized types that manage memory (and sometimes additional resources) for you. They own the data they reference, automatically free it when no longer needed, and remain subject to Rust’s strict borrowing and ownership rules. This chapter examines the most common smart pointers in Rust, compares them to C and C++ strategies, and illustrates how they help avoid pitfalls like dangling pointers and memory leaks—problems historically common in manually managed environments.