- die "$maxk=$stop_at has multiple values" if ref $stop_at;
- my @e;
- local $SIG{__WARN__} = sub { push @e, @_ };
- $stop_at += 0;
- return warn("$maxk=$stop_at: @e") if @e;
+ ref($stop_at) and
+ return warn("$maxk=$stop_at has multiple values\n");
+ ($stop_at =~ /[^0-9]/) and
+ return warn("$maxk=$stop_at not numeric\n");