My question is closely related to the one discussed on this php-dev
thread:
http://thread.gmane.org/gmane.comp.php.devel/32430
Someone just sent me this link, which I didn't find myself when
searching b/c the searches strip "this" from queries.
Anyway, the question is related to reference counting of objects
when
assigned by value and by reference. It is a very important OO topic
as the ability to have a non-ref-counted object "handle" is
basically
requisite to prevent circular reference deadlocks in OO projects.
If the way I have proposed doesn't work, then what is the official
way? And there *must* be one, otherwise, there is no way to avoid
huge memory leaks (deferred release until end-of-script, I know,
but
it's a memory leak in the context of the script while it's running)
with this kind of OO arrangement.
In particular what confuses me is, why does, at least on PHP 5.0.4,
this:
$obj = &$this->this; // doesn't seem to increment the
refcount of the
object
behaves differently from:
$obj = &$this; // does seem to increment the refcount
to the object
References to $this should not only be valid, but are pretty much
required for proper memory management in an OO environment, unless
there is some other sanctioned way to get a weak reference... now I
am not sure if the fact that making a & reference to an object
doesn't increment the refcount is intended behavior, or an
unintended
side effect that may change. This is one of my major questions.
Also, in regards to the thread linked above, I'd say that making
& $this an error is not desirable behavior; but maybe changing the
value of $this should be (ie in C terms, $this is not an lvalue).
Although, in C++/Obj-C you *can* even change this/self... in fact
it's common in Obj-C:
- (id) init
{
if (self = [super init]) { /* etc */ }
return self;
}
Of course PHP is not Obj-C, but it's OO and garbage collected in a
similar way, so PHP has the same need for manipulating $this; that
is, creating weak references.
Alan
On Dec 7, 2005, at 11:27 AM, Antony Dovgal wrote:
On 07.12.2005 18:40, Alan Pinstein wrote:
Hi all-
<skip>
Please use php-general@lists.php.net for questions regarding
development *in* PHP.
--
Wbr, Antony Dovgal
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