by reference (1)

gistfile1.txt

fn getenv_nonempty(v: &Path) -> option<Path> {
        match getenv(*v) {
            some(x) =>
                if str::is_empty(x) {
                    none
                } else {
                    some(x)
                },
            _ => none
        }
    }

    #[cfg(unix)]
    fn lookup() -> Path {
        option::get_default(getenv_nonempty(&(~"TMPDIR")), ~"/tmp")
    }