The cfg attribute can be use to achieve conditional compilation.
// This function only gets compiled if the target OS is linux
#[cfg(target_os = "linux")]
fn are_you_on_linux() {
println!("You are running linux!")
}
// And this function only gets compiled if the target OS is *not* linux
#[cfg(not(target_os = "linux"))]
fn are_you_on_linux() {
println!("You are *not* running linux!")
}
fn main() {
are_you_on_linux();
}