How to Use cfg Attributes for Platform-Specific Code

Use the #[cfg(...)] attribute to conditionally compile code based on the target platform or build configuration. Place the attribute directly above the function, module, or item you want to include only under specific conditions.

#[cfg(target_os = "linux")]
fn linux_specific_setup() {
    // Linux-only code
}

#[cfg(target_os = "windows")]
fn windows_specific_setup() {
    // Windows-only code
}

#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        assert_eq!(2 + 2, 4);
    }
}

cfg attributes let you write different code for different computers or situations without breaking your program. Think of it like a recipe that automatically swaps ingredients based on what's available in your kitchen. You use it to hide test code from your final app or to run specific logic only on Windows or Linux.