Broadcast a signal on a channel

All readers receive zero values on a closed channel.

In this example the Publish function returns a channel, which is used to broadcast a signal when a message has been published.

// Print text after the given time has expired.
// When done, the wait channel is closed.
func Publish(text string, delay time.Duration) (wait <-chan struct{}) {
	ch := make(chan struct{})
	go func() {
		fmt.Println("BREAKING NEWS:", text)
		close(ch) // Broadcast to all receivers.
	return ch

Notice that we use a channel of empty structs: struct{}. This clearly indicates that the channel will only be used for signalling, not for passing data.

This is how you may use the function.

func main() {
	wait := Publish("Channels let goroutines communicate.", 5*time.Second)
	fmt.Println("Waiting for news...")
	fmt.Println("Time to leave.")
Waiting for news...
BREAKING NEWS: Channels let goroutines communicate.
Time to leave.

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