On 11 July 2010 23:19, Daniel Kolbo <kolb0057@xxxxxxx> wrote:
> Hello PHPers,
>
> I'm having some trouble understanding some PHP behaviour. The following
> example script exhibits the behaviour which I cannot understand.
> [code]
> <?php
>
> class A
> {
> public static $a = 3;
>
> function __construct()
> {
> //self::$a = $this; //[i]
> self::$a =& $this; //[ii]
> }
> }
>
> class B extends A
> {
> function __construct()
> {
> parent::__construct();
> }
> }
>
> class C {
> var $c;
>
> function __construct()
> {
> $this->c =& A::$a;
> }
>
> }
>
>
> $c = new C;
> $b = new B;
> $cee = new C;
>
> var_dump($c->c); // [i] prints object(B), but [ii] prints int 3
> var_dump($cee->c); // [i] prints object(B), and [ii] prints object(B)
>
> ?>
> [/code]
>
> Why does $c->c print 'int 3' ?
>
> I'm nervous to use "self::$a = $this;" because I don't want to be
> copying the whole object. However, isn't $this just a reference to the
> object, so "self::$a = $this;" is just copying the reference and not the
> actual object, right?
>
> Thanks in advance
What do you think the value should be?
A static property is bound to the class and not to an instance of the class.
So, &A::$a is a reference to the static value. If you alter the value,
it will be altered for a subclasses of A and for any other reference
to it.
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