proc.Kill() on Windows

[clyq fs]

I tried to stop a waiting process in a goroutine by this on Windows.
But it ends up killing the program immediately. What's your
suggestion? Thanks.


package main

import (
"log"
"os"
"os/exec"
"time"
)

func wait(ch chan *os.Process) {
log.Println(`adb wait-for-device`)

cmd := exec.Command(`adb`, `wait-for-device`)
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
ch <- cmd.Process

if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
}

func main() {
ch := make(chan *os.Process)
go wait(ch)
proc := <-ch
time.Sleep(time.Second * 2)
log.Println("Kill")
proc.Kill()
log.Println("Killed")
time.Sleep(time.Second * 2)
log.Println("Exit")
}


2012/04/26 16:54:52 adb wait-for-device
2012/04/26 16:54:54 Kill
2012/04/26 16:54:54 Killed
2012/04/26 16:54:54 exit status 1

[Dave Cheney]

> I tried to stop a waiting process in a goroutine by this on Windows.
> But it ends up killing the program immediately. What's your
> suggestion? Thanks.

Your program exited when your main goroutine executed

proc.Kill()

Causing this code in your worker goroutine to run

 if err := cmd.Wait(); err != nil {
               log.Fatal(err)
   }

There is a race between log.Fatal() and your final log.Println(). When
you kill a subprocess, it will always exit with a non zero exit code
if it has not already completed.

Cheers

Dave

[clyq fs]

the subprocess in goroutine suppose to wait at least two secs, then killed, but the main is also killed rather than wait another two secs then exit. I would like to know if there is a way prevent parent process being killed.

thanks

[Dave Cheney]

How do you know the parent is being killed? I read it as exiting after log.Fatal. 

[Jiří Zárevúcky]

On Thursday, 26 April 2012 15:36:34 UTC+2, fs wrote:

the subprocess in goroutine suppose to wait at least two secs, then killed, but the main is also killed rather than wait another two secs then exit. I would like to know if there is a way prevent parent process being killed.

As has already been explained, the call to Kill() doesn't kill the parent process.. you do.

log.Fatal() implicitly terminates the entire process.

http://golang.org/pkg/log/#Fatal 

[fs]

Ah, log.Fatal calls os.Exit(1).

Thanks a lot!