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Cargo feature

An optional part of a crate that you switch on in Cargo.toml.

A feature is a named flag declared in [features]; enabling it can turn on optional dependencies and #[cfg(feature = "...")] code. Features are additive: enabling one must never break another.

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Examples

  • [features] unicode = ["dep:unicode-segmentation"] declares a feature; cargo build --features unicode turns on the code under #[cfg(feature = "unicode")].

See also

optional dependency conditional compilation Cargo.toml
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