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To: "PHP Internals" <internals@lists.php.net>,
	"Nikita Popov" <nikita.ppv@gmail.com>
Cc: "Dmitry Stogov" <dmitry@zend.com>
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Date: Wed, 12 Aug 2015 17:10:44 -0500
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Subject: Re: [PHP-DEV] Parameter parsing for zval type?
From: php_lists@realplain.com ("Matt Wilmas")

Hi Nikita,

----- Original Message -----
From: "Nikita Popov"
Sent: Tuesday, August 11, 2015

> On Tue, Aug 11, 2015 at 10:10 PM, Matt Wilmas <php_lists@realplain.com>
> wrote:
>
>> [...]
>>
>> Look at e.g. is_numeric() or strpos() (needle).  Plain zval param 
>> parsing,
>> so NO ZVAL_DEREF() occurs (FAST_ZPP or traditional).  These 2 example
>> functions don't handle IS_REFERENCE type, so they would break.
>>
>> Or is there no way for them (or any function?) to get a IS_REFERENCE?
>> Then *why* is there ZVAL_DEREF() in param parsing functions?  We could
>> remove it!
>>
>> Which is it...?
>>
>
> Functions accepting references are specially marked in arginfo. Normal
> function argument can never be IS_REFERENCE. Reference arguments are 
> always
> IS_REFERENCE. There is also a rarely used mixed mode where both are
> possible. For DEREF-or-not distinction is irrelevant for normal arguments,
> it's only important if an argument is already marked to accept a ref.

Thanks.  Yeah, OK, I see ZEND_SEND_REF creates a reference (if not already), 
which allows the ref'd var to be "recovered" later with ZVAL_DEREF() while 
parsing.  I guess that's right!

I *think* any by-reference argument also needs to be separated during 
parsing (to not affect anything else).  Is that correct logic?  If so, we 
can say that DEREF is only needed if also separating (which only applies to 
array/string/plain zval types, AFAIK).

But what is the "rarely used mixed mode where both are possible?"

> Nikita

Thanks,
Matt