Book Image

Rust Essentials - Second Edition

By : Ivo Balbaert
Book Image

Rust Essentials - Second Edition

By: Ivo Balbaert

Overview of this book

Rust is the new, open source, fast, and safe systems programming language for the 21st century, developed at Mozilla Research, and with a steadily growing community. It was created to solve the dilemma between high-level, slow code with minimal control over the system, and low-level, fast code with maximum system control. It is no longer necessary to learn C/C++ to develop resource intensive and low-level systems applications. This book will give you a head start to solve systems programming and application tasks with Rust. We start off with an argumentation of Rust's unique place in today's landscape of programming languages. You'll install Rust and learn how to work with its package manager Cargo. The various concepts are introduced step by step: variables, types, functions, and control structures to lay the groundwork. Then we explore more structured data such as strings, arrays, and enums, and you’ll see how pattern matching works. Throughout all this, we stress the unique ways of reasoning that the Rust compiler uses to produce safe code. Next we look at Rust's specific way of error handling, and the overall importance of traits in Rust code. The pillar of memory safety is treated in depth as we explore the various pointer kinds. Next, you’ll see how macros can simplify code generation, and how to compose bigger projects with modules and crates. Finally, you’ll discover how we can write safe concurrent code in Rust and interface with C programs, get a view of the Rust ecosystem, and explore the use of the standard library.
Table of Contents (13 chapters)

Pointers and references


Chapter 2, Using Variables and Types, in section, The stack and the heap gave us the basic information we needed to understand memory layout in Rust. Let's recap here, and fill in some gaps.

Stack and heap

When a program starts up, by default a 2 Mb chunk of memory called the stack is granted to it. The program will use its stack to store all its local variables and function parameters, for example an i32 variable takes 4 bytes on the stack. When our program calls a function, a new stack frame is allocated to it. Through this mechanism, the stack knows in which order functions are called, so that functions return correctly to the calling code, while possibly returning values.

Dynamically sized-types, like strings or vectors, can't be stored on the stack. For these values, a program can request memory space on its heap, which is a much bigger piece of memory than the stack.

When possible, stack allocation is preferred in Rust over heap allocation, because accessing the...