I wrote it slightly differently, and it seems to work for me:
#!/usr/bin/perl
use strict;
use warnings;
print "I'm the master ($$)\n";
my %pids;
my $children = 2;
for my $x (1 .. $children) {
my ($fh, $pid);
my $tries = 6;
do {$pid = open $fh, "|-";
unless (defined $pid) {
warn "fork: $!\n";
die "bailing out" unless $tries--;
sleep 5;
}
} until defined $pid;
if ($pid) {
print "I'm master ($$) of child ($pid)\n";
$pids {$pid} = $fh;
}
else {
printf "I'm a child ($$) of master (%d)\n", getppid;
while (<>) {
chomp;
printf "Child ($$) received: [%s]\n", $_;
}
print "Child ($$) exiting\n";
exit;
}
}
my $count = 0;
while (my ($pid, $fh) = each %pids) {
my $data = sprintf "[[%02d]]", ++$count;
printf "Sending data %s to child (%d)\n", $data, $pid;
print $fh $data, "\n";
}
while (my ($pid, $fh) = each %pids) {
printf "Closing handle to child (%d)\n", $pid;
close $fh or warn "Failed to close handle for child ($pid)\n";
}
print "Last line\n";
__END__
I'm the master (19054)
I'm a child (19055) of master (19054)
I'm master (19054) of child (19055)
I'm a child (19056) of master (19054)
I'm master (19054) of child (19056)
Sending data [[01]] to child (19056)
Sending data [[02]] to child (19055)
Closing handle to child (19056)
Child (19056) received: [[[01]]]
Child (19056) exiting
Closing handle to child (19055)
Child (19055) received: [[[02]]]
Child (19055) exiting
Last line
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