环境

• Rust 1.56.1
• VSCode 1.61.2

概念

参考：https://doc.rust-lang.org/stable/rust-by-example/scope/lifetime/fn.html

示例

main.rs

fn print_one<'a>(x: &'a i32) {
    println!("`print_one`: x is {}", x);
}

// 可变的变量生存期标注
fn add_one<'a>(x: &'a mut i32) {
    *x += 1;
}

// 有两个生存期标注
fn print_multi<'a, 'b>(x: &'a i32, y: &'b i32) {
    println!("`print_multi`: x is {}, y is {}", x, y);
}

// 带有返回值的生存期参数
fn pass_x<'a, 'b>(x: &'a i32, _: &'b i32) -> &'a i32 {
    x
}

fn main() {
    let x = 7;
    let y = 9;

    print_one(&x);
    print_multi(&x, &y);

    let z = pass_x(&x, &y);
    print_one(z);

    let mut t = 3;
    add_one(&mut t);
    print_one(&t);
}

总结

了解了 Rust 中的函数的生存期参数的标注。

附录