From: x1 <caldridge@...>
Date: 2005-12-02T22:43:39+09:00
Subject: Problem with method that starts process, yields pid then yields return code

I'm trying to create a method that will kick off a new process, return
it's pid.. while allowing the return code to also be captured for
later examination..
[on windows platform]

class Exec
   def process_handler
       # if I do the following below, it will yield the
       # pid which is great, but because I did not
       # write pipe it to {}, I don't think it's possible to capture
the return_level
       return IO.popen("ruby -e 'sleep 2' &exit 33").pid
   end
end

puts Exec.new.process_handler.to_s # =>  3389
puts $? >> 8 # => gives me an error because I didnt start IO.popen with {}

As a work around, I tried the following:
class Exec
   def process_handler
       # if I do the following below, it will yield the
       # pid which is great, but because I did not
       # write pipe it to {}, I don't think it's possible to capture
the return_level
       Thread.new {
           p = IO.popen("ruby -e 'sleep 2' &exit 33") {}
           $p_return_code = $? >> 8
       }
   return p, $p_return_code
   end
end

The problem here is, p will not be defined until the process has
finished writing to the pipe {}, which will prevent the return of the
pid..

Any suggestions on this?  I'm not able to test this code as I'm using
a machine @ an internet cafe.

Kind regards,
Chris