From: Robert Klemme <shortcutter@...>
Date: 2010-03-02T06:35:11+09:00
Subject: Re: IO.popen with Threads

On 01.03.2010 21:51, Eikichi On wrote:
> Hi everyone,
> 
> I am trying to use IO.popen in order to put and get messages from a
> process to its sub-process (according to
> http://ruby-doc.org/core/classes/IO.html#M002242).
> 
> I am not experimented and I have two questions about:
> 
> 1/ Do threads are a good choice, for read and write at the same time
> (with IO.popen)?

Yes.

> Have you got a simple exemple?

Please see answer to second question.

> 2/ I think IO.popen is useful for asynchrone communication.  But when I
> just need to send a message from a process to its sub-process, and wait
> its answer, how should we do it? (any example is very appreciated)

reply = IO.popen ["cat", "-n"], "r+" do |io|
   rdr = Thread.new { io.read } # alternative: io.readlines
   io.puts "message", "you", "want to send"
   io.close_write

   rdr.value # joins and fetches the result
end

Kind regards

	robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/