Error with session ini setting modification - codeigniter-3

Question

A PHP Error was encountered
Severity: Warning
Message: ini_set(): A session is active. You cannot change the session module's ini settings at this time
Filename: Session/Session.php
Line Number: 316
Backtrace:
File: C:\xampp\htdocs\testing\index.php
Line: 315
Function: require_once
<?php
session_start(); //we need to start session in order to access it through CI
class Adminlogin extends CI_Controller {
public function _construct(){
parent::_construct();
//Load form helper library
$this->load->helper('form');
//Load form validation library
$this->load->library('form_validation');
//Load session library
$this->load->library('session');
//Load database
$this->load->model('login_database');
}
//show login page
public function index()
{
$this->load->view('admin_login');
}
//show registration page
public function user_registration_show(){
$this->load->view('admin_signup');
}
//Validate and store registration data in database
public function new_user_registration(){
//Check Validation for user input in SignUp form
$this->form_validation->set_rules('admin_username', 'Username','trim|required|xss_clean');
$this->form_validation->set_rules('admin_password', 'Password','trim|required|xss_clean');
if($this->form_validation->run()== FALSE){
$this->load->view('admin_signup');}
else{
$data = array(
'admin_username' => $this->input->post('username'),
'admin_password' => $this->input->post('password'));
$result = $this->login_database->registration_insert($data);
if($result == TRUE){
$data['message_display'] = 'Registration Successfully !';
$this->load->view('admin_login', $data);
}else{
$data['message_display'] = 'Username already exist';
$this->load->view('admin_signup',$data);
}
}
}
//Check for user login process
public function user_login_process(){
$this->form_validation->set_rules('admin_username','Username', 'trim|required|xss_clean');
$this->form_validation->set_rules('admin_password','Password', 'trim|required|xss_clean');
if($this->form_validation->run() == FALSE){
if(isset($this->session->userdata['loggen_in'])){
$this->load->view('Admin/admin_dashboard');
}else{
$this->load->view('admin_login');
}
}else{
$data = array(
'admin_username' => $this->input->post('username'),
'admin_password' => $this->input->post('password'));
$result = $this->login_database->login($data);
if($result == TRUE) {
$username = $this->input->post('username');
$result = $this->login_database->read_user_information($username);
if($result != false){
$session_data = array(
'username' => $result[0]->admin_username,
'password' => $result[0]->admin_password);
//Add user data in session
$this->session->set_userdata('logged_in', $session_data);
$this->load->view('Admin/admin_dashboard');
}else{
$data = array(
'error_message' => 'Invalid Username or Password');
$this->load->view('admin_login',$data);
}
}
}
}
}
?>

Answer 1

Please remove the 1st line session_start(); or change it to..
// session_start(); //I do Not need this as I am using CI Sessions.
You are using CodeIgniters Sessions which you have loaded in your code...
$this->load->library('session');
As an Aside:
You don't need the end ?> in your PHP files where it is the last tag in the file.