bitflags

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:

toml [dependencies] bitflags = "2.4.0"

and this to your source code:

rust use bitflags::bitflags;

Example

Generate a flags structure:

```rust use bitflags::bitflags;

// The bitflags! macro generates structs that manage a set of flags. bitflags! { #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] struct Flags: u32 { const A = 0b00000001; const B = 0b00000010; const C = 0b00000100; 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; asserteq!((e1 | e2), Flags::ABC); // union asserteq!((e1 & e2), Flags::C); // intersection asserteq!((e1 - e2), Flags::A); // set difference asserteq!(!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.