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# unserialize

(PHP 3>= 3.0.5, PHP 4 )

unserialize -- Creates a PHP value from a stored representation

## Description

mixed unserialize ( string str)

unserialize() takes a single serialized variable (see serialize()) and converts it back into a PHP value. The converted value is returned, and can be an integer, float, string, array or object. In case the passed string is not unserializeable, `FALSE` is returned.

> Note: It's possible to set a callback-function which will be called, if an undefined class should be instanciated during unserializing. (to prevent getting an incomplete object "__PHP_Incomplete_Class".) Use your `php.ini`, ini_set() or .htaccess-file to define 'unserialize_callback_func'. Everytime an undefined class should be instanciated, it'll be called. To disable this feature just empty this setting.

Example 1. unserialize_callback_func example

    $serialized_object='O:1:"a":1:{s:5:"value";s:3:"100";}';

    ini_set('unserialize_callback_func','mycallback'); // set your callback_function

    function mycallback($classname) {
        // just include a file containing your classdefinition
        // you get $classname to figure out which classdefinition is required
    }

> Note: In PHP 3, methods are not preserved when unserializing a serialized object. PHP 4 removes that limitation and restores both properties and methods. Please see the Serializing Objects section of Classes and Objects or more information.

Example 2. unserialize() example

    // Here, we use unserialize() to load session data to the
    // $session_data array from the string selected from a database.
    // This example complements the one described with serialize().

    $conn = odbc_connect ("webdb", "php", "chicken");
    $stmt = odbc_prepare ($conn, "SELECT data FROM sessions WHERE id = ?");
    $sqldata = array ($PHP_AUTH_USER);
    if (!odbc_execute ($stmt, &$sqldata) || !odbc_fetch_into ($stmt, &$tmp)) {
        // if the execute or fetch fails, initialize to empty array
        $session_data = array();
    } else {
        // we should now have the serialized data in $tmp[0].
        $session_data = unserialize ($tmp[0]);
        if (!is_array ($session_data)) {
            // something went wrong, initialize to empty array
            $session_data = array();
        }
    }

See Also: serialize().

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