# pass it two arrays, by reference.
  sub arrays_equal
  {
    my( $ar1, $ar2 ) = @_;
    @$ar1 eq @$ar2 or return 0; # different lengths.
    # now do member-wise comparison:
    for my $i ( 0 .. $#{$ar1} )
    {
      $ar1->[$i] eq $ar2->[$i] or return 0; # short circuit
    }
    return 1; # all members compared equal.
  }

  # call it like so:
  if ( ! arrays_equal( \@savedpids, \@livepids ) )