The 'static lifetime in Rust

'static means the reference is valid for the whole program, not that the value never moves.

const TITLE: &'static str = "typestar";
static LANGS: [&str; 3] = ["rust", "sql", "css"];

fn remember<T: 'static + std::fmt::Debug>(value: T) {
    println!("{:?} can be stored anywhere", value);
}

fn main() {
    println!("{TITLE} knows {:?}", LANGS);

    let owned = String::from("computed at run time");
    let leaked: &'static str = Box::leak(owned.into_boxed_str());
    println!("{leaked}");

    remember(vec![1, 2, 3]);
}

How it works

1. String literals are &'static str, baked into the binary.
2. A 'static bound on a generic means it owns its data.
3. Leaking a Box is the deliberate way to make one at run time.

Keywords and builtins used here

• Box
• String
• T
• const
• fn
• let
• main
• remember
• static
• str

The run, in numbers

Lines

16

Characters to type

409

Tokens

131

Three-star pace

105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 75 seconds.

Type this snippet

Step 4 of 4 in Lifetime annotations, step 4 of 11 in Lifetimes & interior mutability.

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