I'd rather not hardcode the value like that. See if you can get some reasonable information from the error, when being cast to exec.ExitError. I think you should be able to get ProcessState.Sys which 'returns system-dependent exit information about the process. Convert it to the appropriate underlying type, such as syscall.WaitStatus on Unix, to access its contents. ' from there you should be able to get some system-wide constant.

agree, this isn't a reasonable fix

Since you've already created that method just:

if errnoError(err) == syscall.ECHILD {
...

How about:

if se, ok := err.(*os.SyscallError); ok {
    if errno, ok := se.Err.(syscall.Errno); ok {
        return errno
    }
}

return 0

thanks, done