Re: Static Class Member References

Richard Quadling wrote: > On 12 July 2010 22:54, Daniel Kolbo <kolb0057@umn.edu> wrote: >> Richard Quadling wrote: >>> On 11 July 2010 23:19, Daniel Kolbo <kolb0057@umn.edu> 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. >>> >> I think >> var_dump($c->c); would print object(B), but it's printing int 3. >> >> The reference is *not* being updated. I think this is a bug. What do >> you think? >> >> Thanks >> ` >> >> > > What version of PHP are you using? > I'm using: PHP Version 5.2.13