1//! ## Documentation: Feature Flags 2//! 3//! Available [compile-time feature flags](https://doc.rust-lang.org/cargo/reference/features.html#dependency-features) 4//! 5//! #### Default Features 6//! 7//! * **std**: _Not Currently Used._ Placeholder for supporting `no_std` environments in a backwards compatible manner. 8//! * **color**: Turns on colored error messages. 9//! * **help**: Auto-generate help output 10//! * **usage**: Auto-generate usage 11//! * **error-context**: Include contextual information for errors (which arg failed, etc) 12//! * **suggestions**: Turns on the `Did you mean '--myoption'?` feature for when users make typos. 13//! 14//! #### Optional features 15//! 16//! * **deprecated**: Guided experience to prepare for next breaking release (at different stages of development, this may become default) 17//! * **derive**: Enables the custom derive (i.e. `#[derive(Parser)]`). Without this you must use one of the other methods of creating a `clap` CLI listed above. 18//! * **cargo**: Turns on macros that read values from [`CARGO_*` environment variables](https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates). 19//! * **env**: Turns on the usage of environment variables during parsing. 20//! * **unicode**: Turns on support for unicode characters (including emoji) in arguments and help messages. 21//! * **wrap_help**: Turns on the help text wrapping feature, based on the terminal size. 22//! * **string**: Allow runtime generated strings (e.g. with [`Str`][crate::builder::Str]). 23//! 24//! #### Experimental features 25//! 26//! **Warning:** These may contain breaking changes between minor releases. 27//! 28//! * **unstable-replace**: Enable [`Command::replace`](https://github.com/clap-rs/clap/issues/2836) 29//! * **unstable-v5**: Preview features which will be stable on the v5.0 release 30