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Posted by Steve on 09/24/07 21:08
"gosha bine" <stereofrog@gmail.com> wrote in message
news:46f823bf$0$31121$6e1ede2f@read.cnntp.org...
> Shelly wrote:
>> "Steve" <no.one@example.com> wrote in message
>> news:r6VJi.36$Nr6.32@newsfe05.lga...
>>> "Joe" <joe@faceh.com> wrote in message
>>> news:1190663828.772978.15800@22g2000hsm.googlegroups.com...
>>>> I am just starting to use Object Oriented PHP coding, and I am seeing
>>>> quite often the following (this example taken from a wiki):
>>>>
>>>> $wakka =& new Wakka($wakkaConfig);
>>>>
>>>> What exactly is the =&, and why is it different from = ?
>>> well, better syntax would have helped. it should read ' $something =
>>> &$variable'. in this context, & means 'a reference to the memory
>>> location where the value is stored'. without the &, it means 'a copy of
>>> the value of the variable'.
>>>
>>> clear as mud? rather than explain memory, let me have you do this:
>>>
>>> $variable = 'hello';
>>> $reference = &$variable;
>>> $variable = 'world';
>>> echo '<pre>' . print_r($reference, true) . '</pre>';
>>> $reference = 'good-bye';
>>> echo '<pre>' . print_r($variable, true) . '</pre>';
>>>
>>> unset($variable);
>>> unset($reference);
>>>
>>> $variable = 'hello';
>>> $reference = $variable;
>>> $variable = 'world';
>>> echo '<pre>' . print_r($reference, true) . '</pre>';
>>> $reference = 'good-bye';
>>> echo '<pre>' . print_r($variable, true) . '</pre>';
>>>
>>> the first example, BY REFERENCE, means that both $variable and
>>> $reference point to the same memory location. changing one but using the
>>> other makes no difference - using either will have the same effect.
>>>
>>> the second, BY VALUE, means that each variable points to two different
>>> locations in memory. the only time they will be equal is when setting
>>> them so. once you modify one of them, you have done so idependently of
>>> the other - changing one has no effect on the other.
>>>
>>> hope that makes more sense.
>>
>> That was probably the single most unique new concept (pointers and
>> address-of) I had conquer when (os so many years ago) I learned C, coming
>> from a Fortran background as I did.
>>
>> Shelly
>
> php references have nothing to do with C-alike pointers.
>
> Please read the chapter called "references are not pointers" in the
> manual.
'chapter' ? oh, you mean the quoted text of a usenet post? may i ask, who is
jani?
" For the 2nd time: references ARE NOT POINTERS! :-p
--Jani
"
hmmm, i see the strong case being made here! kind of like:
"for the nth time! toothfairies ARE REAL!"
gosha, you'd be wise at this point to draw the distinctions yourself (if not
capable, use a supported reference [no pun]). but, since references provide
identical behaviors to pointers, the only difference that i see is the
literal words themselves (one, 'pointer', the other, 'reference')...and
perhaps some symantics somewhere.
as it is, REFERENCES like POINTERS speak to POINTING TO AN ADDRESS or a COPY
OF A VALUE AT AN ADDRESS...which is EXACTLY WHAT A POINTER IS/DOES. not to
mention that AT LENGTH, php has discussed that the biggest change/hurdle
when moving from php < 5 to php >= 5 will be how objects are going to be
passed BY REFERENCE instead of byVal from here on out.
however, since you don't like me calling you an idiot when i see you being
one, you have killfiled my responses...like a child. so, you won't even feel
corrected. if you do read this post, and not being able to provide a valid
counter, you'll pretend not to see this post out of shear convenience...and
the side-effect of saving face.
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