Question

I am new to codeigniter.

I want to know use of $CI =& get_instance();

is this use for error logging or global config variable.

thanks in advance.

Answer 1

From CodeIgniter manual:

$CI =& get_instance();

Once you’ve assigned the object to a
variable, you’ll use that variable
instead of $this:

$CI =&get_instance();

$CI->load->helper('url');
$CI->load->library('session');
$CI->config->item('base_url'); etc.

Note: You’ll notice that the above
get_instance() function is being
passed by reference:

$CI =& get_instance();

This is very important. Assigning by
reference allows you to use the
original CodeIgniter object rather
than creating a copy of it.

Also, please note: If you are running
PHP 4 it’s usually best to avoid
calling get_instance() from within
your class constructors. PHP 4 has
trouble referencing the CI super
object within application constructors
since objects do not exist until the
class is fully instantiated.

Link:
http://codeigniter.com/user_guide/general/creating_libraries.html