session_unset

(PHP 4, PHP 5)

session_unset — Détruit toutes les variables d'une session

Description

void session_unset ( void )

session_unset() détruit toutes les variables de la session courante.

Valeurs de retour

Aucune valeur n'est retournée.

Notes

Note: Si vous utilisez $_SESSION (ou $HTTP_SESSION_VARS pour PHP 4.0.6 ou plus ancien), utilisez unset() pour détruire une variable de session, i.e. unset($_SESSION['nomvariable']);.

Attention

Ne détruisez pas $_SESSION avec unset($_SESSION) car cela désactivera la possibilité d'enregistrer des variables de session à partir du tableau superglobal $_SESSION.

session_write_close

session_unregister

Last updated: Fri, 20 Jun 2008

add a note User Contributed Notes
session_unset

00 at f00n dot com
23-Jun-2008 07:00


-------------------------------------------------------

InterNic

20-May-2006 11:20 

sometimes you might have problems even if using both session_unset and session_destroy. You have to clear the $_SESSION array. I got it working this way:



session_unset();

session_destroy();

$_SESSION = array();

-------------------------------------------------------



When I used this method the session still existed in structure until the array is reset completely.



This, however, has the drawback of clearing all sessions which may not be ideal in some cases.



Named sessions may help in such cases.

pentek_i at inf dot elte dot hu
08-Aug-2006 04:54


You should know that on recent PHP only the first one of these functions works correctly. And if you use the other two, var_dump will print you the result you expected (session cleaned up), but the session file on the server won't be cleaned up. So use the first one.



<?php



function session_clean1($logout=false)

 {

  $v=array();

  foreach($_SESSION as $x=>$y)

   if($x!="redirector"&&($x!="user"||$logout))

    $v[]=$x;



  foreach($v as $x)

   unset($_SESSION[$x]);

  return;

 }



function session_clean2($logout=false)

 {

  foreach($_SESSION as $x=>$y)

   if($x!="redirector"&&($x!="user"||$logout))

    unset($_SESSION[$x]);

  return;

 }



function session_clean3($logout=false)

 {

  $s=($logout||!isset($_SESSION["user"]))?array():

   array("user"=>$_SESSION["user"]);

  if(isset($_SESSION["redirector"]))

   $s["redirector"]=$_SESSION["redirector"];

  $_SESSION=$s;

 }



?>



On previous php (<<5.1.4) releases at least the third one worked correctly.

InterNic
20-May-2006 03:20


sometimes you might have problems even if using both session_unset and session_destroy. You have to clear the $_SESSION array. I got it working this way:



session_unset();

session_destroy();

$_SESSION = array();

07-Mar-2006 07:56


Yes, that's how it is, first you write session_unset, and then the sentence session_distroy

zach at zkwarta dot com
13-Jul-2005 03:32


The difference between both session_unset and session_destroy is as follows:



session_unset just clears out the sesison for usage. The session is still on the users computer. Note that by using session_unset, the variable still exists.



Using session_unset in tandem with session_destroy however, is a much more effective means of actually clearing out data. As stated in the example above, this works very well, cross browser:



session_unset();

session_destroy();



I noticed that in firefox, one could simply use sesison_unset and the session would be cleared. When trying this on IE, I was horrified to find out that the data was still there, so I had to use session destroy.

Jeroen
15-Jan-2005 01:42


note to Jason: I don't know the exact mechanics of it (since I'm quite new to sessions) but I think you need to use session_unset() BEFORE you can use session_destroy() at all.  I thought that session_unset() was for scripted variables, and session_destroy() just for anything saved on your side regarding the session.

21-Mar-2001 08:58


To further clarify the note above... this can be done via the session handling directives in your php.ini file... there are options to set garbage collection probability (via percent... i.e. 75 means it would run 3 out of every 4 page accesses), and the amount of time a session object can remain active before the garbage collection process sees it as garbage.

dmertens at zyprexia dot com
31-Jan-2001 09:11


The session files are automaticly deleted after the session-timeout is reached. So if the time-out is set to 20 minutes, the files will be deleted 20 minutes after the last access. Same for the cookie. Every time, an page is requested, the cookie-ttl is set to now + 20 minutes.





PHP is a very clean scripting engine, which leaves no garbage on your system!

j a s o n p 0 1 9 at yahoo dot com
13-Jul-2000 01:26


session_unset() vs. session_destroy():


I would say that the difference is that session_destroy() destroys the session variables, both in the script and where the session data is stored on disk.  session_unset() is like doing a session_unregister() on all registered variables.  They can still be re-registered by calling session_register() whereas after session_destroy, they cannot.

add a note

session_write_close

session_unregister

Last updated: Fri, 20 Jun 2008