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    $_SESSION

    (PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

    $_SESSION — Variables de sesión

    Descripción

    Es un array asociativo que contiene variables de sesión disponibles para el script actual. Ver la documentación de Funciones de sesión para más información sobre su uso.

    Notas

    Nota:

    Esta es una 'superglobal' o una variable automatic global. Significa simplemente que es una variable que está disponible en cualquier parte del script. No hace falta hacer global $variable; para acceder a la misma desde funciones o métodos.

    Ver también

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    User Contributed Notes 3 notes

    up
    104
    Tugrul
    9 years ago
    Creating New Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    ?>
    Getting Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    /*session created*/
    echo $_SESSION["newsession"];
    /*session was getting*/
    ?>
    Updating Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    /*it is my new session*/
    $_SESSION["newsession"]=$updatedvalue;
    /*session updated*/
    ?>
    Deleting Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    unset(    $_SESSION["newsession"]);
    /*session deleted. if you try using this you've got an error*/
    ?>
    up
    11
    bohwaz
    16 years ago
    Please note that if you have register_globals to On, global variables associated to $_SESSION variables are references, so this may lead to some weird situations.

    <?php

    session_start    ();

    $_SESSION['test'] = 42;
    $test = 43;
    echo     $_SESSION['test'];

    ?>

    Load the page, OK it displays 42, reload the page... it displays 43.

    The solution is to do this after each time you do a session_start() :

    <?php

    if (ini_get('register_globals'))
    {
    foreach (    $_SESSION as $key=>$value)
    {
    if (isset(    $GLOBALS[$key]))
    unset(    $GLOBALS[$key]);
    }
    }

    ?>
    up
    -1
    opajaap at opajaap dot nl
    11 years ago
    Be carefull with $_SESSION array elements when you have the same name as a normal global.

    The following example leads to unpredictable behaviour of the $wppa array elements, some are updated by normal code, some not, it is totally unpredictable what happens.

    <?php
    global $wppa;
    $wppa = array( 'elm1' => 'value1', 'elm2' => 'value2', ....etc...);

    if ( !     session_id() ) @ session_start();
    if ( ! isset(    $_SESSION['wppa']) $_SESSION['wppa'] = array();

    if ( ! isset(    $_SESSION['wppa']['album']) ) $_SESSION['wppa']['album'] = array();
    $_SESSION['wppa']['album'][1234] = 1;

    $wppa['elm1'] = 'newvalue1';

    print_r($_SESSION);
    ?>
    This will most likely display Array ( [wppa] => Array ( [album] => Array ( [1234] => 1 ) [elm1] => 'newvalue1' [elm2] => 'value2' ... etc ...
    But setting $wppa['elm1'] to another value or referring to it gives unpredictable results, maybe 'value1', or 'newvalue1'.

    The most strange behaviour is that not all elements of $wppa[xx] show up as $_SESSION['wppa'][xx].
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