From: Robert Klemme <shortcutter@...>
Date: 2009-12-27T02:55:15+09:00
Subject: Re: How to know if a process is zombie?

On 26.12.2009 17:53, Iņaki Baz Castillo wrote:
> Hi, after some forks I need to know if a process still is alive or not, but in 
> case it's alive I also need to know if it's a zombie process (it died without 
> Process.wait or Process.detach).
> 
> Unfortunatelly I couln't find how to know it using Process module:
>   http://ruby-doc.org/core/classes/Process.html
>   http://ruby-doc.org/core/classes/Process/Status.html
> 
> Is there any other way to determine if a given PID is zombie?

I believe you can use Process.kill(0, suspicious_pid) and if you get 
"Errno::ESRCH: No such process" it does not exist any more or is a 
zombie.  Then you can use Process.waitpid(suspicious_pid, 
Process::WNOHANG) to end his martyrdom and get the exit code.

It's probably better to set up a signal handler though.  But that 
totally depends on your use case.

Kind regards

	robert

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