Exit status without os.Exit

[Tobias Matt]

Today I learned, that defer don't work with os.Exit, but how can I
return an exit status without os.Exit?

[Evan Shaw]

On Mon, Aug 8, 2011 at 9:36 AM, Tobias Matt <t.ma...@gmail.com> wrote:
> Today I learned, that defer don't work with os.Exit, but how can I
> return an exit status without os.Exit?

Defer doesn't work with os.Exit, but it's easy to work around;

package main

import (
"fmt"
"os"
)

func main() {
os.Exit(realMain())
}

func realMain() int {
defer fmt.Println("hi")
return 1
}

- Evan

[Paul Borman]

It is more complicated than that when you have more than a single goroutine.  This solution also does not allow exiting the program anyplace but from realMain.  If you are single threaded you can implement an exit using panic and a deferred recover, but that will not help if you have multiple goroutines.  os.Exit doesn't unwind anything, panic unwinds the stack it is on.  I have brought this up on the dev mailing list.  I think having the ability to exit a program and have all stacks unwound and defers called would require a language change.

    -Paul

[Julien Laffaye]

On 08/07/2011 23:46, Paul Borman wrote:
> It is more complicated than that when you have more than a single
> goroutine. This solution also does not allow exiting the program
> anyplace but from realMain. If you are single threaded you can
> implement an exit using panic and a deferred recover, but that will
> not help if you have multiple goroutines. os.Exit doesn't unwind
> anything, panic unwinds the stack it is on. I have brought this up on
> the dev mailing list. I think having the ability to exit a program
> and have all stacks unwound and defers called would require a language
> change.

You want something like atexit(3).
Maybe it could be implemented with os.signal and a slice of functions to
run when the process is about to exit.

[jimmy frasche]

os.Exit(<-exit_code)

[Russ Cox]

http://groups.google.com/group/golang-nuts/t/a814346cadb3bd00