   #PHP Manual Variable Functions strval unset

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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 [, string callback])

   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.

     unserialize_callback_func directive: It's possible to set a
     callback-function which will be called, if an undefined class
     should be instantiated during unserializing. (to prevent getting an
     incomplete object "__PHP_Incomplete_Class".) Use your php.ini,
     ini_set() or .htaccess to define 'unserialize_callback_func'.
     Everytime an undefined class should be instantiated, it'll be
     called. To disable this feature just empty this setting. Also note
     that the directive unserialize_callback_func directive became
     available in PHP 4.2.0.

     Note: The callback parameter was added in PHP 4.2.0

   If the variable being unserialized is an object, after successfully
   reconstructing the object PHP will automatically attempt to call the
   __wakeup() member function (if it exists).

   Example 1. unserialize_callback_func example
   <?php
   $serialized_object='O:1:"a":1:{s:5:"value";s:3:"100";}';
   // unserialize_callback_func directive available as of PHP 4.2.0
   ini_set('unserialize_callback_func', 'mycallback'); // set your
   callback_function
   function mycallback($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
   <?php
   // 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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