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session_unset

(PHP 4, PHP 5, PHP 7, PHP 8)

session_unset — Libera todas as variáveis de sessão

Descrição

session_unset(): void

A função session_unset() libera todas as variáveis atualmente registradas na sessão.

Valor Retornado

Nenhum valor é retornado.

Notas

Nota:
Se $_SESSION (ou $HTTP_SESSION_VARS para PHP 4.0.6 ou inferior) for usada, use unset() para desregistrar a variável da sessão, isto é, unset ($_SESSION['varname']);.

Cuidado

NÃO elimine completamente $_SESSION com unset($_SESSION) já que isto desabilitará o registro de variáveis de sessão através da super global $_SESSION.

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User Contributed Notes 4 notes

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tim at leethost dot com ¶

11 years ago

I was having a problem clearing all session variables, deleting the session, and creating a new session without leaving old session stuff behind in all browsers.  The below code is perfect for a logout script to totally delete everything and start new.  It even works in Chrome which seems to not work as other browsers when trying do logout and start a new session.

<?php
    session_start();
    session_unset();
    session_destroy();
    session_write_close();
    setcookie(session_name(),'',0,'/');
    session_regenerate_id(true);
?>

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jerry ¶

7 years ago

The difference between both session_unset and session_destroy is as follows:

session_unset just clears out the session for usage. The session is still on the users computer. Note that by using session_unset, the variable still exists. session_unset just remove all session variables. it does not destroy the session....so the session would still be active.

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_destroy is destroy the session. session_destroy() to kill all session information.....This is the more secure function to use.

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-15

Jeroen ¶

18 years ago

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.

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-30

zach at zkwarta dot com ¶

18 years ago

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.

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