Ch1. Getting started

Cargo Overview

• Cargo: Rust’s build system and package manager.
  • Manages tasks like building code, downloading dependencies, and building libraries.
  • Simplifies adding dependencies for more complex projects.
• Most Rust projects use Cargo, and the text assumes Cargo usage throughout.

Creating a Cargo Project

• To create a new project:

  cargo new hello_cargo
  cd hello_cargo

  • Creates a project directory with:
    • Cargo.toml: Configuration file in TOML format.
    • src/main.rs: Contains the main program.
    • .gitignore: Initializes a Git repository (can be skipped with --vcs flag).

Project Structure

• Cargo organizes files:
  • Top-level directory: For configuration files like Cargo.toml, README, and license information.
  • src directory: Holds the source code.
• To convert a non-Cargo project, move the code to src and create a Cargo.toml file.

Building and Running with Cargo

• Build the project:

  cargo build

  • Generates the executable in target/debug.
  • To run:

  ./target/debug/hello_cargo

  • Cargo.lock: Tracks exact versions of dependencies.

• Run and build in one step:

  cargo run

• Skips rebuild if no changes are detected.

Checking Code without Building

• Use cargo check for faster compile checks without generating an executable:

  cargo check

Building for Release

• For optimized builds:

  cargo build --release

• Produces a binary in target/release.

• Optimizations improve runtime performance but increase compile time.