note 99668 added to language.references
| From: | dev dot php at linke-t dot net | Date: | Mon, 30 Aug 2010 09:01:16 +0000 |
| Subject: | note 99668 added to language.references | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-172155@lists.php.net to get a copy of this message | ||
I thought Yeah pointer likly behavior... but i watched serilized objects and what i did see?
referenced Objects are outputed like the object self.
Here is a simple code, it shows that the references are sweet but in some case (storing objects to
$_SESSION or Database) unuseable:
<?php
class foo{
private static $id_c = 0;
public $ref;
public $id;
public function foo(){
$this->id=self::$id_c++;
}
}
$a = new foo();
$b = new foo();
$a->ref = &$b;
print_r($a);
echo "<br/>";
print_r($b);
echo "<br/><br/>";
$a->ref->id++;
echo "increment \$a->ref->id++;<br/><br/>";
print_r($a);
echo "<br/>";
print_r($b);
echo "<br/><br/>";
echo "\$a2=unserialize(serialize(\$a));<br/><br/>";
$a2=unserialize(serialize($a));
print_r($a2);
echo "<br/>";
print_r($b);
echo "<br/><br/>";
$a2->ref->id++;
echo "increment \$a2->ref->id++;<br/><br/>";
print_r($a2);
echo "<br/>";
print_r($b);
echo "<br/>";
?>
Output on PHP 5.3.3:
foo Object ( [ref] => foo Object ( [ref] => [id] => 1 ) [id] => 0 )
foo Object ( [ref] => [id] => 1 )
increment $a->ref->id++;
foo Object ( [ref] => foo Object ( [ref] => [id] => 2 ) [id] => 0 )
foo Object ( [ref] => [id] => 2 )
$a2=unserialize(serialize($a));
foo Object ( [ref] => foo Object ( [ref] => [id] => 2 ) [id] => 0 )
foo Object ( [ref] => [id] => 2 )
increment $a2->ref->id++;
foo Object ( [ref] => foo Object ( [ref] => [id] => 3 ) [id] => 0 )
foo Object ( [ref] => [id] => 2 )
after unserialize $a2->ref isn't any more a reference.
To save items for the next request, you must avoid references and save all objects of a class in an
array. To get a PHP-reference you could write a function like:
<?php
function get_obj_by_ref($ref){
global $_array_where_objects_of_class_foo_are_stored;
$r = &$_array_where_objects_of_class_foo_are_stored[$ref];
return $r;
}
?>
I am unhappy about this behavior of PHP. I does not watch like a feature ... ;)
----
Server IP: 69.147.83.197
Probable Submitter: 91.39.87.88
----
Manual Page -- http://www.php.net/manual/en/language.references.php
Edit -- https://master.php.net/note/edit/99668
Del: integrated -- https://master.php.net/note/delete/99668/integrated
Del: useless -- https://master.php.net/note/delete/99668/useless
Del: bad code -- https://master.php.net/note/delete/99668/bad+code
Del: spam -- https://master.php.net/note/delete/99668/spam
Del: non-english -- https://master.php.net/note/delete/99668/non-english
Del: in docs -- https://master.php.net/note/delete/99668/in+docs
Del: other reasons-- https://master.php.net/note/delete/99668
Reject -- https://master.php.net/note/reject/99668
Search -- https://master.php.net/manage/user-notes.php