perl -le 'printf "%.18f", 10.1'
10.099999999999999645

##</code><code>##

    # Fix for Perl and sprintf not rounding up like Excel.
    # http://rt.cpan.org/Public/Bug/Display.html?id=45626
    if ( $data =~ /^${number_result}5/ ) {
        $number_result =
            sprintf "%0${str_length}.${after_decimal}f",
            $data . '1';
    }