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To: Patrick ALLAERT <patrickallaert@php.net>
Cc: PHP Development <internals@lists.php.net>
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Date: Wed, 05 Jan 2011 19:15:34 +0100
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Subject: Re: [PHP-DEV] Memory usage and refcount
From: johannes@php.net (Johannes =?ISO-8859-1?Q?Schl=FCter?=)

On Wed, 2011-01-05 at 18:30 +0100, Patrick ALLAERT wrote:

> <?php
> class foo {
>     static function def() {
>         // $x as a static *function* var
>         static $x = "foo";
>         return $x;

$x is a reference to the static variable. It has to since assignment to
$x, which is a local variable, should change the static variable. This
is returned using copy semantis so we can't do copy on write.

Whereas with 

> class foo {
>     // $x as a static *class* var
>     static $x = "foo";
>     static function def() {
>         return self::$x;
>     }
> }

you are explicitly referencing the static class property. CoW can work
properly.

johannes