why ini_set('session.gc_maxlifetime',60) doesn't work?

Question

the default expire time of session is 1440,i want to reduce this time to 60 second,but when i use ini_set('session.gc_maxlifetime','60') in the first page it work,but it doesn't work in an other page, please tell me what is my wrong?

    ----------index.php-----------
    <?php
    ini_set('session.gc_maxlifetime','60');
    session_start();       

    $_SESSION['id']='123';

    print('<br/><a href="link.php">link<a/>');
    ?>


    ----------link.php----------
    <?php
    session_start();

    if(isset($_SESSION['id'])){
        ini_set('session.gc_maxlifetime',60);
    }else{
        header('Location:index.php?ERROR');
    }

    print('<br/><a href="link.php?1">menu<a/>');
    ?>

Answer 1

Because garbage collector starts (if starts) before session

So setting ini_set('session.gc_maxlifetime',60); after session_start() changes nothing

Answer 2

The session garbage collector will fire as part of session_start(). Since you're changing the setting AFTER you start a session, you're too late to change the settings.