A couple suggestions from the Perl Cookbook -- not sure if they are what you need but here they are.

16.19 Avoiding Zombie Processes

If you don’t need to record the children that have terminated, use:

$SIG{CHLD} = 'IGNORE';

If you do, use a SIGCHLD handler:

$SIG{CHLD} = \&REAPER;
sub REAPER {
my $stiff;
while (($stiff = waitpid(-1, WNOHANG)) > 0) {
# do something with $stiff if you want
}
$SIG{CHLD} = \&REAPER; # install *after* calling waitpid
}
[download]

some info on waitpid & WNOHANG: