Validation callback with input value as argument

[eluser]Santiag0[/eluser]
[quote author="pistolPete" date="1239713906"]Do you really need to edit more than one database entry per page?

By the way:

Code:

// you need TWO underscores here: callback_ + _user_exists
$this->form_validation->set_rules('username[]', 'user name', 'trim|required|callback__user_exists');

[/quote]

Sorry, I make a mistake in that line, but is not the point.
I need to check if the username exist ONLY if has a diferent ID, because this is a control panel to manage all users of a system.
So I need to deal with the user_id[] value of the hidden input.

Thanks