Doc says
session_create_id() is used to create new session id for the current session. session_regenerate_id() Update the current session id with a newly generated one.
Is there any difference between these two functions ?
Create new session id
Update the current session id with a newly generated one
Usage example from the manual:
$old_sessionid = session_id();
// Set destroyed timestamp
$_SESSION['destroyed'] = time(); // Since PHP 7.0.0 and up, session_regenerate_id() saves old session data
// Simply calling session_regenerate_id() may result in lost session, etc.
// See next example.
session_regenerate_id();
// New session does not need destroyed timestamp
unset($_SESSION['destroyed']);
$new_sessionid = session_id();
echo "Old Session: $old_sessionid<br />";
echo "New Session: $new_sessionid<br />";
print_r($_SESSION);
Which leads us to the following question - why and when you should use it, there's a detailed answer in this link.
Yes there is a difference, session_create_id() will create a new sessionId discarding the current $_SESSION information, where as session_regenerate_id() doesn't destroys them, instead it just updates the sessionId
Referred from : http://php.net/manual/en/function.session-create-id.php & http://php.net/manual/en/function.session-regenerate-id.php