Create custom library

[eluser]Tommy Liu[/eluser]
Dear experts - I have no idea that why I cannot call the function that I stored in my custom library called "Udpwebdb.php".

If I remove quota lines in function as below. I can show the result correctly. Please give me some hints to me to fix the problem. Thank you.

$this->load->library('udpwebdb');
printf('%s',this->updwebdb->tabletojson());

Code:

public function myctrlresult()
{
$this->load->library('udpwebdb');
printf('%s',this->updwebdb->tabletojson());
printf('%s','here');
}

File fullname: ../library/Udpwebdb.php

Code:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Udpwebdb {

    public function tabletojson()
    {
     return 'hello';
    }
}