From: Jeff Putsch <putsch@...>
Date: 2002-08-23T07:35:38+09:00
Subject: Why  does this hang?

Howdy,

I've got a simple test routine using Open3.popen3 and it hangs when checking 
for EOF on the stderr IO object that Open3.popen3 returns. Here's the
simple program:

  def run_command
   stdin, out, err =  Open3.popen3("cat /etc/ifhp.conf")
  
      while not out.eof? and not err.eof?
        select_on = []
        select_on.push(out) unless out.eof?
        select_on.push(err) unless err.eof?
  
        r = select(select_on)
        p r
  
        r[0].each { |fh|
  	if fh == out
  	  puts "out: #{fh.gets.to_s}"
  	end
  	if fh == err
  	  puts "err: #{fh.gets.to_s}"
  	end
        }
        $stdout.flush
    end
  
  
  end
  
  run_command

When I run this, it hangs at the "while  not ..." line. If I don't check for
"err.eof?", then it never hangs.

I don't understand what is going on. Any help/guidance/suggestions will
be greatly appreciated.

Jeff.
-- 
Jeff Putsch                       Email: putsch@mxim.com
Maxim Integrated Products        Office: (503)547-2037
High Frequency CAD Engineering