commit	3661f15a6ce2e514d9969a863d1b74ce3c54f383	[log] [tgz]
author	James Farrell <[email protected]>	Tue May 21 15:05:54 2024 +0000
committer	Automerger Merge Worker <[email protected]>	Tue May 21 15:05:54 2024 +0000
tree	843f6409b281e80510410d566e992774628c9a41
parent	49d0ff92a508992550dcaafd4084fd115351199e [diff]
parent	72e001aa680f7609da94c0c86a9ef22c789d7c82 [diff]

tree: 843f6409b281e80510410d566e992774628c9a41

README.md

bitflags

License

bitflags generates flags enums with well-defined semantics and ergonomic end-user APIs.

You can use bitflags to:

provide more user-friendly bindings to C APIs where flags may or may not be fully known in advance.
generate efficient options types with string parsing and formatting support.

You can't use bitflags to:

guarantee only bits corresponding to defined flags will ever be set. bitflags allows access to the underlying bits type so arbitrary bits may be set.
define bitfields. bitflags only generates types where set bits denote the presence of some combination of flags.
Documentation
Specification
Release notes

Usage

Add this to your Cargo.toml:

[dependencies]
bitflags = "2.4.2"

and this to your source code:

use bitflags::bitflags;

Example

Generate a flags structure:

use bitflags::bitflags;

// The `bitflags!` macro generates `struct`s that manage a set of flags.
bitflags! {
    /// Represents a set of flags.
    #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
    struct Flags: u32 {
        /// The value `A`, at bit position `0`.
        const A = 0b00000001;
        /// The value `B`, at bit position `1`.
        const B = 0b00000010;
        /// The value `C`, at bit position `2`.
        const C = 0b00000100;

        /// The combination of `A`, `B`, and `C`.
        const ABC = Self::A.bits() | Self::B.bits() | Self::C.bits();
    }
}

fn main() {
    let e1 = Flags::A | Flags::C;
    let e2 = Flags::B | Flags::C;
    assert_eq!((e1 | e2), Flags::ABC);   // union
    assert_eq!((e1 & e2), Flags::C);     // intersection
    assert_eq!((e1 - e2), Flags::A);     // set difference
    assert_eq!(!e2, Flags::A);           // set complement
}

Rust Version Support

The minimum supported Rust version is documented in the Cargo.toml file. This may be bumped in minor releases as necessary.