use strict;
use warnings;

use IO::Socket;

my $handle;
my $pid;
if (!defined($pid = open($handle, "|-"))) {
	die "Fork failed: ".$!;
}
elsif ($pid == 0) {
	# Child
	sleep(5);
	exit 0;
}
else {
	# Parent
	$handle->autoflush(1);
	my $i = 0;
	my $result;
	do {
		$result = print $handle "ABC\n";
		print "PIPE write ".++$i."\n";
	} while ($result);
}