On Linux, with Perl 5.8.0 (but on many another combination of OS and Perl version) the following code doesn't do what I expect:

#!/usr/bin/perl
use POSIX qw(pause);
use strict;
my $ppid=$$;
$SIG{HUP}=sub {return};
my $pid=fork;
if ($pid){
    pause;
    print "parent woke up\n";
    waitpid $pid,0;
    print "parent reaped child\n";
} else {
    die "fork error $!" if (!defined $pid);
    sleep 2; # what can I say, it works.
    print "child is about to signal parent (at $ppid)\n";
#    `kill -1 $ppid`;
    my $cnt=kill,1,$ppid;
    print "child signaled $cnt process(es)\n";
    print "child about to exit\n";
    exit;
}
[download]

This program outputs the following:

hbo@owen|1337> perl test
child is about to signal parent (at 24421)
child signaled 0 process(es)
child about to exit
[download]

A 'kill -1 $ppid' from the shell gets the program unstuck. If I comment out the internal kill function and subsequent print statement, and uncomment the back-tick kill, it works as I'd like:

hbo@owen|1338> perl test
child is about to signal parent (at 24428)
parent woke up
child about to exit
parent reaped child
[download]

I've never gotten Perl's built-in kill to work for me. Any ideas?