Macro std::option_env1.0.0[][src]

macro_rules! option_env {
    ($name : expr $(,) ?) => { ... };
Expand description

Optionally inspects an environment variable at compile time.

If the named environment variable is present at compile time, this will expand into an expression of type Option<&'static str> whose value is Some of the value of the environment variable. If the environment variable is not present, then this will expand to None. See Option<T> for more information on this type.

A compile time error is never emitted when using this macro regardless of whether the environment variable is present or not.


let key: Option<&'static str> = option_env!("SECRET_KEY");
println!("the secret key might be: {:?}", key);