php - Calling model from codeigniter library shows error -

hello have created library auth.php in application/libraries authenticate if current user logged in or not. controller :

$session_data = $this->session->userdata('logged_in'); $this->load->library('auth'); $auth = new auth; $user_id = $auth->authenticate($session_data); 

and library :

class auth{     function authenticate($vars){          $ci =&get_instance();         $ci->load->model('adminmodels/login_model');          $username = $vars['username'];         $password = $vars['password'];         $user_id = $vars['user_id'];;         $user_type = $vars['user_type'];          $check_login = $this->login_model->login($username,$password); //line 14          if($check_login){             $user_id = $user_id;         }else{             $user_id = 0;         }          return $user_id;    } } 

but showing error :

a php error encountered

severity: notice

message: undefined property: auth::$login_model

filename: libraries/auth.php

line number: 14

whats wrong doing ??

while correct generally, in ci should call library this, not new keyword:

$this->load->library('auth'); $user_id = $this->auth->authenticate($session_data); 

also, since assigned global ci object variable, can't use $this refer it:

    $check_login = $this->login_model->login($username,$password); //line 14 

should be:

    $check_login = $ci->login_model->login($username,$password); //line 14 

(since loaded model there: $ci->load->model('adminmodels/login_model'); )