vendor/crossbeam-channel/examples/stopwatch.rs

   1 //! Prints the elapsed time every 1 second and quits on Ctrl+C.
   2
   3 #[cfg(windows)] // signal_hook::iterator does not work on windows
   4 fn main() {
   5     println!("This example does not work on Windows");
   6 }
   7
   8 #[cfg(not(windows))]
   9 fn main() {
  10     use std::io;
  11     use std::thread;
  12     use std::time::{Duration, Instant};
  13
  14     use crossbeam_channel::{bounded, select, tick, Receiver};
  15     use signal_hook::iterator::Signals;
  16     use signal_hook::SIGINT;
  17
  18     // Creates a channel that gets a message every time `SIGINT` is signalled.
  19     fn sigint_notifier() -> io::Result<Receiver<()>> {
  20         let (s, r) = bounded(100);
  21         let signals = Signals::new(&[SIGINT])?;
  22
  23         thread::spawn(move || {
  24             for _ in signals.forever() {
  25                 if s.send(()).is_err() {
  26                     break;
  27                 }
  28             }
  29         });
  30
  31         Ok(r)
  32     }
  33
  34     // Prints the elapsed time.
  35     fn show(dur: Duration) {
  36         println!(
  37             "Elapsed: {}.{:03} sec",
  38             dur.as_secs(),
  39             dur.subsec_nanos() / 1_000_000
  40         );
  41     }
  42
  43     let start = Instant::now();
  44     let update = tick(Duration::from_secs(1));
  45     let ctrl_c = sigint_notifier().unwrap();
  46
  47     loop {
  48         select! {
  49             recv(update) -> _ => {
  50                 show(start.elapsed());
  51             }
  52             recv(ctrl_c) -> _ => {
  53                 println!();
  54                 println!("Goodbye!");
  55                 show(start.elapsed());
  56                 break;
  57             }
  58         }
  59     }
  60 }