Function std::env::var_osUnstable

pub fn var_os<K: ?Sized>(key: &K) -> Option<OsString> where K: AsOsStr

Fetches the environment variable key from the current process, returning None if the variable isn't set.

Example

fn main() { use std::env; let key = "HOME"; match env::var_os(key) { Some(val) => println!("{}: {:?}", key, val), None => println!("{} is not defined in the environment.", key) } }

use std::env;

let key = "HOME";
match env::var_os(key) {
    Some(val) => println!("{}: {:?}", key, val),
    None => println!("{} is not defined in the environment.", key)
}