Can't access session data session_write_close - php

Question

I was having issues with the session file being locked, so I added session_write_close() once I was done with the session. The script worked properly before that, however, once I leave the sign-in page now, the session is blank.
Session is started at the top of index.php which includes the sign in page:
$result = 'token_valid';
$_SESSION['user'] = $email;
print_r($_SESSION);
session_write_close();
print_r($_SESSION);
The session data is returned properly both times on the sign-in page.
Array ( [user] => abc#gmail.com ) Array ( [user] => abc#gmail.com )
A link returns to the home page, which calls a function to check if logged in...
function user_is_signed_in() {
print_r($_SESSION);
session_write_close();
if($user == '') {
return False;
}
else {
return True;
}
}
The session no longer has any data.
Full index.php
<?php
session_start();
include_once('fnc/database.php');
include_once('fnc/user.php');
if(!user_is_signed_in()) {
include('sign-in.php');
}
else {
$url = parse_url($_SERVER['REQUEST_URI']);
if(!$url['query'])
{
include('home.php');
}
else {
if(isset($_GET['media']))
{
include($_GET['media'].'.php');
}
if(isset($_GET['user']))
{
include($_GET['user'].'.php');
}
}
}
.
.
Workaround (probably filthy)
Issue seems to be caused by the reading/writing of the actual session file. Used the session_id generated by PHP and just created a secondary session file. Do not save in same folder (or if you do, change the filename) - session_start seems to delete and regenerate the session file PHP manages and you'll lose any data written there.
session_start();
$sess = array();
$sess = $_SESSION;
$sess["id"] = session_id();
//print_r($sess);
session_write_close();
Create session_data in session folder
$session_details = "user|".$email;
$session_file = "/Programs/XAMPP/tmp/session_data/sess_".$sess["id"];
//echo $session_details;
$fh = fopen($session_file, 'w+');
fwrite($fh, $session_details);
fclose($fh);
Read session data from this file instead of the session
$session_path = "/Programs/XAMPP/tmp/session_data/sess_".$sess["id"];
$fh = fopen($session_path, 'r');
$session_file = fread($fh, filesize($session_path));
$exploded_session = explode("\n", $session_file);
$session_data = array();
foreach($exploded_session as $line)
{
$tmp = explode("|", $line);
$session_data[$tmp[0]] = $tmp[1];
}
return $session_data["user"];
fclose($fh);