how to set session time out in php?
<pre><code>session_cache_expire( 20 );
session_start(); // NEVER FORGET TO START THE SESSION!!!
$inactive = 1200;
if(isset($_SESSION['start']) ) {
    $session_life = time() - $_SESSION['start'];
    if($session_life &gt; $inactive){
        header("Location: user_logout.php");
    }
}
$_SESSION['start'] = time();
if($_SESSION['valid_user'] != true){
header('Location: ../index.php');
}else{
</code></pre>

<p>I'm making an online examination system. I'm using PHP and MySQL.</p>

<p>I want to set the session time, but don't know how. Please help me.</p>

<p>Thanks in advance</p>
