# Function std::env::var_os [−] [src]

    pub fn var_os<K: AsRef<OsStr>>(key: K) -> Option<OsString>

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

# Examples

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)
    }

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