#!/usr/bin/perl -w

use strict;

use IO::Select;
use IO::Pipe;
use IO::Handle;

my $debug = 1;

my @connect = ("3","2","1");

my %msgs;
@msgs{@connect} = qw/hooray hip hip/;

my $select_ch = IO::Select->new();

foreach my $msg (@connect) {
    # for each write, fork a child
    if ($msg) {
        # fork and open child for reading
        my $pipe = IO::Pipe->new();

        if (my $pid = fork() ) {
	    #parent
	    my $fh = $pipe->reader();
	    $debug && print "parent $$ forked $pid\n";
	    $fh->blocking(0);	# set non-blocking I/O
	    $debug && print "parent adding readable filehandle ($fh)\n";
	    $select_ch->add($fh);
        } else {
	    #child
	    my $childhandle = $pipe->writer();
	    my $mt = $msgs{$msg};
	    sleep $msg;
	    print STDERR "$$ child $msg writing to pipe $msg, response $mt\n";
	    print $childhandle "child $msg, response $mt";
	    exit 0;		#kill the child process
        }
    }
}				# done with processing this read

# here we read for responses from the filehandles
my @readyfiles;			#array for select to populate
while ( @readyfiles = $select_ch->can_read() ) {
    foreach my $rh (@readyfiles) {
	# read from filehandle, send back string

	print "$$ calling IO::Handle::getline\n";

	my $child_resp_string = $rh->getline();

	$debug && print "$$ read |$child_resp_string|\n";

	# only one read per handle, so close
	$debug && print "$$ removing @{[ref $rh]}\n";
	$select_ch->remove($rh);
	$rh->close;

	$debug && print "$$ @{[$select_ch->count()]} handles left to read\n";
    }
}
print "exiting...\n";
exit 0;

##</code><code>##

le99007@robin:~/src/perl> ./pipe.pl 
parent 7146 forked 7147
parent adding readable filehandle (IO::Pipe::End=GLOB(0x195708))
parent 7146 forked 7148
parent adding readable filehandle (IO::Pipe::End=GLOB(0x1957a4))
parent 7146 forked 7149
parent adding readable filehandle (IO::Pipe::End=GLOB(0x151eb0))
7149 child 1 writing to pipe 1, response hip
7146 calling IO::Handle::getline
7146 read |child 1, response hip|
7146 removing IO::Pipe::End
7146 2 handles left to read
7148 child 2 writing to pipe 2, response hip
7146 calling IO::Handle::getline
7146 read |child 2, response hip|
7146 removing IO::Pipe::End
7146 1 handles left to read
7147 child 3 writing to pipe 3, response hooray
7146 calling IO::Handle::getline
7146 read |child 3, response hooray|
7146 removing IO::Pipe::End
7146 0 handles left to read
exiting...