Golang : Call a function after some delay(time.Sleep and Tick)

Long time ago when I started learning Turbo Pascal by myself. One of the few functions that I'd learned is the delay() function. Ah... those days..very nostalgic.

Anyway, these programs below will show you how to call a function after some delay. First example uses the time.Sleep() function and the second example uses the time.Tick() function.

Example 1:

 package main

 import (
 "fmt"
 "time"
 )

 func delaySecond(n time.Duration) {
 time.Sleep(n * time.Second)
 }

 func delayMinute(n time.Duration) {
 time.Sleep(n * time.Minute)
 }

 func main() {

 fmt.Println("starts")

 delaySecond(3) // delay 3 seconds

 fmt.Println("after 3 second")

 delayMinute(1) // delay 1 minute

 fmt.Println("after 1 minute delay... now get back to work!")

 }

Example 2 - For polling after 5 seconds

 package main

 import (
 "fmt"
 "time"
 )

 func echo(s string) {
 fmt.Println(s)
 }

 func delaySecond(n time.Duration) {
 for _ = range time.Tick(n * time.Second) {
 str := "Hi! " + n.String() + " seconds have passed"
 echo(str)
 }
 }

 func main() {

 go delaySecond(5) // very useful for interval polling

 select {} // this will cause the program to run forever
 }

The reason second example used the time.Tick() function is because time.Sleep() function will cause this error :

fatal error: all goroutines are asleep - deadlock!

Output : see http://play.golang.org/p/W3EYOHA-YS

Reference :

https://groups.google.com/forum/#!topic/golang-nuts/W1KJQr35NE0