destroy session php

session_destroy(); // To delete whole session
// OR
unset($_SESSION['myVar']); // To delete a session var

// destroy the session
<?php
session_destroy();
?>

<?php 
 session_start(); // start session
 session_destroy();  // Delete whole session
// OR
unset($_SESSION['username']); // delete any specific session only
?>

<?php
// Destroy the currently active session.
session_destroy();
?>

<?php
session_destroy();
?>

<?php
   session_start();
   $_SESSION['var'];
?>