Comments and documentation - Rust for C-Programmers

2.16 Comments and Documentation

Rust, like C, supports // for single-line comments and /* ... */ for multi-line comments. Additionally, Rust provides documentation comments that can be processed by tools like rustdoc to generate HTML documentation.

2.16.1 Comments

#![allow(unused)]
fn main() {
// This is a single-line comment

/*
   This is a multi-line comment
*/
}

2.16.2 Documentation Comments

Rust supports special documentation comments:

/// documents the next item (e.g., a function or struct).
//! documents the enclosing scope, such as a module or crate.

#![allow(unused)]
fn main() {
//! This module provides basic mathematical operations for `i32` values.

/// Adds two numbers.
///
/// # Examples
///
/// ```
/// let result = add(2, 3);
/// assert_eq!(result, 5);
/// ```
fn add(a: i32, b: i32) -> i32 {
    a + b
}
}

The rustdoc tool extracts these comments to generate structured HTML documentation. Additionally, multi-line documentation comments starting with /** or /*! are supported but are less commonly used.