How to use bitflags crate in Rust bit flags

Use the bitflags! macro to define a type-safe wrapper around an integer that supports bitwise operations and flag combinations.

use bitflags::bitflags;

bitflags! {
    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
    struct Permissions: u8 {
        const READ = 0b00000100;
        const WRITE = 0b00000010;
        const EXECUTE = 0b00000001;
    }
}

fn main() {
    let read_write = Permissions::READ | Permissions::WRITE;
    assert!(read_write.contains(Permissions::READ));
}

Bitflags let you group related on/off settings into a single number, like a light switch panel where each switch controls a different feature. You use them when you need to track multiple independent states efficiently, such as file permissions or user roles. Instead of managing separate booleans, you combine them into one value and check for specific settings using simple math.