The Go Programming Language

8.7 Multiplexing with select

The program below does the countdown for a rocket launch. The time.Tick function returns a channel on which it sends events periodically, acting like a metronome. The value of each event is a timestamp, but it is rarely as interesting as the fact of its delivery.

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gopl.io/ch8/countdown1

func main() {
    fmt.Println("Commencing countdown.")
    tick := time.Tick(1 * time.Second)
    for countdown := 10; countdown > 0; countdown-- {
        fmt.Println(countdown)
        <-tick
    }
    launch()
}

Now let’s add the ability to abort the launch sequence by pressing the return key during the countdown. First, we start a goroutine that tries to read a single byte from the standard input and, if it succeeds, sends a value ...