sub reap_child {
   while ( (my $child = waitpid(-1,WHNOHANG)) > 0) {
      $CHILDREN{$child}->($child) if ref $CHILDREN{$child} eq 'CODE';
      delete $CHILDREN{$child};
   }
}

##</code><code>##

sub kill_children {
   kill TERM => keys %CHILDREN;
   sleep while %CHILDREN;
}