Return value

The tokio::select! macro returns the result of the evaluated <handler> expression.

  1. async fn computation1() -> String {
  2.     // .. computation
  3. }
  5. async fn computation2() -> String {
  6.     // .. computation
  7. }
  9. #[tokio::main]
  10. async fn main() {
  11.     let out = tokio::select! {
  12.         res1 = computation1() => res1,
  13.         res2 = computation2() => res2,
  14.     };
  16.     println!("Got = {}", out);
  17. }

Because of this, it is required that the <handler> expression for each branch evaluates to the same type. If the output of a select! expression is not needed, it is good practice to have the expression evaluate to ().