Conditional compilation is possible through two different operators:
the cfg attribute: #[cfg(...)] in attribute position
the cfg! macro: cfg!(...) in boolean expressions
Both utilize identical argument syntax.
// 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();
println!("Are you sure?");
if cfg!(target_os = "linux") {
println!("Yes. It's definitely linux!");
} else {
println!("Yes. It's definitely *not* linux!");
}
}