From: Andreas S <andreas_s@...>
Date: 2007-03-01T09:35:30+09:00
Subject: Re: How to check if child process is still alive?


>You have to call  Process.wait to reap the child process in order for the 
>child process to disappear  entirely.
>
>Gary Wright
>

I don't want to use Process.wait because it will block. I have a queue that 
I want to refill with the next job in line when a slot is available. I'm not 
gaining much from forking jobs like this but my main purpose is to emulate 
LSF queue on local machine, in case its down or something. By doing so, the 
rest of the code still sees a queue.

I tried Ara's suggestion, but it doesn't seem to throw exception.

Thanks for such prompt response and I love how Ara, even for merely showing 
example, gave
  alias alive? alive
:)

-andre

def alive pid
  pid = Integer("#{ pid }")
  begin
    Process::kill 0, pid
    true
  rescue Errno::ESRCH
    false
  end
end

c = fork do
   sleep 5
   print "Child exits"
   exit
end

while alive c
  print '.'; STDOUT.flush
  sleep 1
end

>>ruby test.rb
......Child exits.........

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