會話超時PHP問題

Question

我想超時會話，如果用戶不使用的網站。我已經看到了被他人使用該功能在互聯網上：

ini_set('session.gc_maxlifetime', 10); 

我我把這個函數放在我的代碼中，但沒有任何反應。不超時，我沒有錯誤。我究竟做錯了什麼？

下面是我把它放在代碼：

<?php 
ini_set('session.gc_maxlifetime', 10); 
session_start(); 
ob_start(); 
include("dbinfo.inc.php"); 

$comm=@mysql_connect($host,$username,$password); 
$rs=@mysql_select_db($database) or die("Unable to select database"); 

// username and password sent from form 
$myusername=$_POST['username']; 
$mypassword=$_POST['password']; 

// To protect MySQL injection 
$myusername = stripslashes($myusername); 
$mypassword = stripslashes($mypassword); 
$myusername = mysql_real_escape_string($myusername); 
$mypassword = mysql_real_escape_string($mypassword); 
$sql="SELECT * FROM login WHERE username='$myusername' and password=sha1('$mypassword')"; 
$result=mysql_query($sql); 

// Mysql_num_row is counting table row 
$count=mysql_num_rows($result); 

// If result matched $myusername and $mypassword, table row must be 1 row 
if($count==1) 
{ 
// Register $myusername, $mypassword and redirect to file "home.html" if successful 
$_SESSION['username'] = $myusername; 
$_SESSION['password'] = $mypassword; 
header("Location:home.php"); 
} 
?> 

Answer 1

<?php 
    session_start(); 

    include("dbinfo.inc.php"); 

    if(empty($_SESSION['username'])){ 

    echo "Please login.Time out"; 


    }