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As a reference lifetime 'static indicates that the data pointed to by the reference lives for the entire lifetime of the running program.
In Rust global variables are declared with the static keyword. In C there is a difference between static variables (with translation unit scope) and non-static global variables (with truly global scope).
7 months ago. by John Otieno. A static variable refers to a type of variable that has a fixed memory location. They are similar to constant variables except they represent a memory location in the program.
I am trying to make this simple code compile:
fn dox(x: u8) -> u8 { x*2 }
fn main() {
let cb: &'static (Fn(u8) -> u8) = &dox;
}
But it fails with Rust 1.9:
x.rs:4:40: 4:43 error: borrowed value does not live long enough
x.rs:4 let cb: &'static (Fn(u8) -> u8) = &dox;
^~~
note: reference must be valid for the static lifetime...
x.rs:4:44: 5:2 note: ...but borrowed value is only valid for the block suffix following statement 0 at 4:43
x.rs:4 let cb: &'static (Fn(u8) -> u8) = &dox;
x.rs:5 }
error: aborting due to previous error
How is it possible that a free function does not have static lifetime? How could this code be unsafe?
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