Rather silly question - extending core library

Hi everyone, 
I tho up to now I know codeigniter very well ... well - I don't. 
I have some CMS system build using CI2.0 + DataMapper (I know, I know - but I'm just employee) and trying to add some function to Upload library, so I can do:

PHP Code:

$this->upload->something($some_data); 


however adding in core folder MY_Upload that extends CI_Upload, throws an error. 
Is it possible in CI to extend Upload this way ?
Thanks - Matt.

Have a look at this:
https://www.codeigniter.com/userguide3/g...aries.html

Are you adding MY_Upload.php to /application/core/ or to system/core/?

It should be the former. Also check config.php and confirm that

PHP Code:

$config['subclass_prefix'] = 'MY_; 


The upload class isn't a core file. It doesn't belong in core, it belongs in libraries.

Expert Website Development - Temecula, CA
Community Auth For CodeIgniter 3

The upload class isn't a core file. It doesn't belong in core, it belongs in libraries.

Well, ya. There is that.