pdo stored procedure output param

[gerhardt7]

i have made a logon script but he must give a output parameter "relatieid" but if i do print relatieid i don't get the output parameter. what can i do to get the output parameter. i must give -1 if your logon data don't be good and your relatie id if you are succesfull logon. i saw that you can use fatchall but how

my script is:

<?php
session_start();
$sessieid = session_id();
error_reporting(-1);
ini_set('display_errors', 1);

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
     $username = $_POST['username'];
     $wachtwoord = $_POST['wachtwoord'];
     $ip = $_SERVER["REMOTE_ADDR"];
     $computernaam = php_uname('n'); 

 if(trim($username) == '')
 {
    echo "<font color='red'>Vul geldige gebruikersnaam in!</font><br>";
    header("refresh:5;url=/login/");
exit() ;
}    

 if(trim($wachtwoord) == '')
 {
    echo "<font color='red'>Vul geldige wachtwoord in!</font><br>";
    header("refresh:5;url=/login/");
exit() ;
} 


$db = new PDO('mssql:host=localhost\snelstart;dbname=SluisWWW','test','********'); 

$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$stmt = $db->prepare("EXECUTE spMagInvoeren ?,?,?,?,?,?,?");

$stmt->bindValue(1 ,$username, PDO::PARAM_STR);
$stmt->bindValue(2 ,$wachtwoord);
$stmt->bindValue(3 ,$ip);
$stmt->bindValue(4 ,$computernaam);
$stmt->bindValue(5 ,$sessieid);
$stmt->bindParam(6 ,$poging);
$stmt->bindParam(7 ,$relatieid);

$stmt->execute(); 

 print "<br/>Returned: $relatieid<br/><br/>\r\n";





{
    setcookie("TestCookie", $username);
    // redirecten
    exit();
}


}