# std::env!1.0.0 [−] [src]

    macro_rules! env {
        ($name:expr) => { ... };
    }

1.0.0

Inspect an environment variable at compile time.

This macro will expand to the value of the named environment variable at compile time, yielding an expression of type `&'static str`.

If the environment variable is not defined, then a compilation error will be emitted. To not emit a compile error, use the `option_env!` macro instead.

# Examples

fn main() { let path: &'static str = env!("PATH"); println!("the $PATH variable at the time of compiling was: {}", path); }

    let path: &'static str = env!("PATH");
    println!("the $PATH variable at the time of compiling was: {}", path);

# Help

## Keyboard Shortcuts

?
  Show this help dialog
S
  Focus the search field
⇤
  Move up in search results
⇥
  Move down in search results
⏎
  Go to active search result

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)