time.AfterFunc() Function in Golang With Examples
In Go language, time packages supplies functionality for determining as well as viewing time. The AfterFunc() function in Go language is used to wait for the duration of time to pass and after that, it calls the defined function “f” in its own go-routine. Moreover, this function is defined under the time package. Here, you need to import the “time” package in order to use these functions.
Syntax:
func AfterFunc(d Duration, f func()) *Timer
Here, *Timer is a pointer to the Timer.
Return Value: It returns a Timer which is then used to cancel the call with the help of its Stop() method.
Example 1:
// Golang program to illustrate the usage of // AfterFunc() function // Including main package package main // Importing fmt and time import ( "fmt" "time" ) // Main function func main() { // Defining duration parameter of // AfterFunc() method DurationOfTime := time .Duration(3) * time .Second // Defining function parameter of // AfterFunc() method f := func() { // Printed when its called by the // AfterFunc() method in the time // stated above fmt.Println( "Function called by " + "AfterFunc() after 3 seconds" ) } // Calling AfterFunc() method with its // parameter Timer1 := time .AfterFunc(DurationOfTime, f) // Calling stop method // w.r.to Timer1 defer Timer1.Stop() // Calling sleep method time .Sleep(10 * time .Second) } |
Output:
Function called by AfterFunc() after 3 seconds
Here, the output is returned after 3 seconds and then the returned timer cancels the call to the function using Stop() method. After then the program is exited after the duration of sleep ends.
Example 2:
// Golang program to illustrate the usage of // AfterFunc() function // Including main package package main // Importing fmt and time import ( "fmt" "time" ) // Main function func main() { // Creating channel using // make keyword mychan := make(chan int ) // Calling AfterFunc() method // with its parameters time .AfterFunc(6* time .Second, func() { // Printed after stated duration // by AfterFunc() method is over fmt.Println( "6 seconds over...." ) // loop stops at this point mychan <- 30 }) // Calling for loop for { // Select statement select { // Case statement case n := <-mychan: // Printed after the loop stops fmt.Println(n, "is arriving" ) fmt.Println( "Done!" ) return // Returned by default default : // Printed until the loop stops fmt.Println( "time to wait" ) // Sleeps for 3 seconds time .Sleep(3 * time .Second) } } } |
Output:
time to wait time to wait 6 seconds over.... 30 is arriving Done!
In the above example, after the stated duration is over then channel returns its output and the program exits.