Testing if $_SESSION variables work in WordPress/PHP.

init_session_var_test.php

function init_session_var_test()
{
    //must set /?sessiontest=SOMETHING to get this to run
    if(empty($_REQUEST['sessiontest']))
        return;
    
    //start session
    if (version_compare(phpversion(), '5.4.0', '>=')) {
        if (session_status() == PHP_SESSION_NONE)
            session_start();
    }
    else {
        if(!session_id())
            session_start();
    }
    
    //show old value
    echo "Old value: " . $_SESSION['sessiontest'] . "<br />";
    
    //set from REQUEST
    $_SESSION['sessiontest'] = $_REQUEST['sessiontest'];
    
    //show new value
    echo "New value: " . $_SESSION['sessiontest'] . "<br />";
    
    exit;
}
add_action('init', 'init_session_var_test');