From: ara.t.howard@...
Date: 2006-11-17T08:53:04+09:00
Subject: Re: popen, open3 problems

On Fri, 17 Nov 2006, Peter Schrammel wrote:

> Hi,
>
> I think this problem is surely solved but hven't found anything on the net:
>
> I get two programs:
> 1. a ruby (master)
> 2. a perl (slave)
>
> I want the master to set commands to the slave and wait for the answer
> (repeatedly). So a conversation could look like this:
>
> m: set_var
> m: v=8
> s: set
> m: get_var
> m: v
> s: 8
> ...
>
> The problem is that ruby refuses to write to stdin of the slave until I
> close the pipe. But I want to use the pipe repeatedly. Did I miss
> something about IPC?


   man stdio
   /buffer

>
> My curent progs look like this:
>
>
> require 'fcntl'
> require 'open3'

     harp:~ > cat a.rb
     require 'open3'

     Open3.popen3 "perl a.pl" do |i,o,e|
       i.puts 'set_var'
       i.puts 'v=8'
       i.flush                              #   <<---

       puts o.gets
     end


     harp:~ > cat a.pl

     $| = 1;                                #   <<---

     while ($line = <STDIN>) {
       chomp($line);
       if ($line eq "set_var") { &set_var;}
       elsif ($line eq "quit") { exit 0;}
     }

     sub set_var { $var=<STDIN>; chomp($var); print "set.$var\n"; }


     harp:~ > ruby a.rb
     set.v=8


-a
-- 
my religion is very simple.  my religion is kindness. -- the dalai lama