I have a much larger program that this goes with, but even the smaller example does not seem to work. I tried initially to use the pipe command, and then switched to open(READ, "-|") command -- but both exhibit the same behavior: I do not get any data from the child until the child closes his end. Here is my example code:

#!/usr/bin/perl -w
use strict;

if (my $pid = open(READ, "-|")) {
  print "child said: '", <READ>, "'; ",time,"\n";
  print "child said: '", <READ>, "'; ",time,"\n";
} else {
  print "hello; ",time,"\n";
  sleep 2;
  print "how are you; ",time,"\n";
}

[download]
I receive this as output: 
gryn@echor:~$ ./testcase.pl
child said: 'hello; 1005587480
how are you; 1005587482
'; 1005587482
child said: ''; 1005587482

[download]

I'm quite perplexed, and I've read over and over the various examples in the documentations (such as perlipc's numerous ones). I just can figure it out.

I am running with perl 5.6, on a intel debian unstable box; in case that matters.


Ciao,
Gryn

In reply to Open, ye! And read from your child! by gryng

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.