Share session between Core Php & CodeIgniter

Question

I have a web app which is in Core PhP. And we are moving it to CI Framework step by step.

Problem: Need to share session value between them.

Core PHP App Dir Structure:|-- /xampp/lms/
Core PHP App URL: http://localhost/lms/index.php

CI App Dir Structure: |-- /xampp/lms/newlms/
CI App URL: http://localhost/lms/newlms/index.php/login

CI Configuration:

config.php

$config['sess_driver'] = 'database';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 7200;
$config['sess_save_path'] = 'ci_sessions';
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = FALSE;

$config['cookie_prefix']    = '';
$config['cookie_domain']    = '';
$config['cookie_path']      = '/';
$config['cookie_secure']    = FALSE;
$config['cookie_httponly']  = FALSE;

What I have did so far.

Core PHP changes
Path: \xampp\htdocs\lms\configuration.inc.php (this is file called first in core php)

session_name('ci_session');
session_start();

echo '<pre>';
echo '<br/>------------- session_save_path-------- <br/>';
print_r(session_save_path());
echo '<br/>------------- session_name-------- <br/>';
print_r(session_name());
echo '<br/>------------- $_COOKIE -------- <br/>';
print_r($_COOKIE);
echo '<br/>------------- $_SESSION -------- <br/>';
print_r($_SESSION);
exit;  

output:

------------- session_save_path-------- 
\xampp\tmp
------------- session_name-------- 
ci_session
------------- $_COOKIE -------- 
Array (
    [ci_session] => 2b9tj8rek53kapgsuh4k3v2fuuvblvq9
)

------------- $_SESSION -------- 
Array (
    some values which I have set in Core php
)  

Session Path xampp\tmp\sess_2b9tj8rek53kapgsuh4k3v2fuuvblvq9

CI changes
path: \xampp\htdocs\lms\newlms\application\modules\login\controllers

Class Login extends MX_Controller {

   function __construct() {
     parent::__construct();
   }

   function index() {
echo '<pre>';
echo '<br/>------------- session_save_path-------- <br/>';
print_r(session_save_path());
echo '<br/>------------- session_name-------- <br/>';
print_r(session_name());
echo '<br/>------------- $_COOKIE -------- <br/>';
print_r($_COOKIE);
echo '<br/>------------- $_SESSION -------- <br/>';
print_r($_SESSION);
exit;
   }
 }

output:

------------- session_save_path-------- 
\xampp\tmp
------------- session_name-------- 
ci_session
------------- $_COOKIE -------- 
Array (
    [ci_session] => 2b9tj8rek53kapgsuh4k3v2fuuvblvq9
)

------------- Core $_SESSION -------- 
Array (
    [__ci_last_regenerate] => 1479978675
)

------------- CI $_SESSION -------- 
CI_Session Object (
 .. Some values.
)

PS: I have tried to explain in best way but Before Down Voting please share the reason.

Answer 1

As suggested by bertmaclin,

CI's session handler is just a wrapper of the php session handler

Have tweek CI's config.php & session Library.

CI config.php: added given code just before base_url configuration.

session_start();

CI Session.php: added @ before session_start() in session library line #142.

@session_start();