From: Robert Klemme <shortcutter@...>
Date: 2009-08-26T18:13:11+09:00
Subject: Re: Asynchronous process to process pipe IO

2009/8/25 Pito Salas <rps@salas.com>:
> Robert Klemme wrote:
>
>> Then you'll want to use one of the popen family of functions.  Even with
>> IO.popen you can pass arguments:
>>
>> IO.popen ["./iacommand.rb", "arg", "arg"] do |io|
>>    ...
>> end
>>
>> Note, if you also want to write to the process's stdin, you need to
>> provide a file mode as second argument.  See docs.
>
> This is what I originally had. Pretty similar...
>
> open("|-", "r") do |worker|
>    if worker
> ...
>    else
>      exec("./iacommand.rb", "arg", "arg")
>    end
>  end
>
> How do you think that the idea you show above is different/better?

I would prefer IO.popen as it is shorter - and it does not need
cryptic (aka perlish) file names:

IO.popen ["./iacommand.rb", "arg", "arg"], "rw" do |io|
  # no if here either
  io.puts "start"
  io.close_write

  io.each_line do |line|
    puts "GOT: #{line}"
  end
end

> This
> gets pretty subtle... Thanks again for the great thread about Threads :)

Sorry, I do not find it that subtle.  IMHO it is pretty obvious that
IO.popen is superfior for the job you want to get done.  That is, of
course, unless I am missing something...

Kind regards

robert

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