When the code is ran time taken by attack() function is printed sometimes I know their is race condition when attack writes to channel and main reads it then main exits and doesn't wait for timer("attack") to execute
I am new to go:_)
package main
import (
"fmt"
"time"
)
func timer(funcName string) func(){
startTime := time.Now()
return func(){
fmt.Printf("%s took %v time to run \n", funcName, time.Since(startTime))
}
}
func main(){
defer timer("main")()
smokeSignal := make(chan bool)
evilNinga := "Tommy"
go attack(evilNinga, smokeSignal)
fmt.Println(<-smokeSignal)
}
func attack(target string, smokeSignal chan<-bool){
defer timer("attack")()
time.Sleep(time.Second)
fmt.Println("Throwing ninja stars at ", target)
smokeSignal <- true
}
Can some tell how to handle this case, I want to print time taken by both the function, and use channels
Can some tell how to handle this case
When main exits, the program is terminated, there is no graceful termination of concurrent goroutines (in many programs the non-main goroutines are ancillary "daemons" and not expected to shut down at all) so no guarantee extant defers will run. This is what occurs here: when you send the smoke signal, if the attack goroutine is descheduled then main can return before it gets re-scheduled, and thus defer never runs.
There are a number of options to handle this issue, but all of them lead to basically the same thing: ensure you send on the channel after the function has run, which you can do by for instance (non-exhaustive)