# The following prints:
   # /abu-jeib/teaching/Fall_06/207/Examples/Lec18_Files/current_alumni_sessions.php
   // echo $_SERVER['PHP_SELF'], "<br />"; 
   # The following prints the same as the one above
   // echo $_SERVER['REQUEST_URI'], "<br />";
   # The following prints /opt/lampp/htdocs
   // echo $_SERVER['DOCUMENT_ROOT'], "<br />";
   # The following prints www.cs.fredonia.edu
   // echo $_SERVER['SERVER_NAME'], "<br />";

/* Check if cookies are disabled.*/

if (!isset($_COOKIE["PHPSESSID"]) && !isset($_GET["PHPSESSID"]))
{  
	
  $redirect = "http://".$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];
  $id = strip_tags(SID);
  # Don't replace SID by session_id() in the above.
  header("Location: ".$redirect."?$id");
  # header("Location: ".$redirect."?SID"); # NO
  exit;
}
elseif (!isset($_COOKIE["PHPSESSID"]) && isset($_GET["PHPSESSID"]))
{  
  exit("<p align=center>You have to enable cookies to log in.</p>");
}