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Date: Sat, 26 Nov 2016 12:29:47 +0100
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Subject: Re: [PHP-DEV] Translating optional zval **
 withzend_parse_parameters() to PHP 7
From: cmbecker69@gmx.de ("Christoph M. Becker")

On 26.11.2016 at 01:47, Thomas Hruska wrote:

> Okay, everyone has been helpful.  Thanks.  I'll go with:
> 
> 
>     zval *zprevcount = NULL;
>     zend_long count;
> 
>     if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|z/",
> &zprevcount) == FAILURE)  return;
> 
>     ...
> 
>     if (zprevcount != NULL)
>     {
>         count = (zend_long)PrevCount;
> 
>         zval_dtor(zprevcount);
>         ZVAL_LONG(zprevcount, count);
>     }
> 
> 
> Just one little thing I found in php_str_replace_common() in
> ext/standard/string.c.  That particular function calls zval_ptr_dtor()
> instead of zval_dtor() on zcount.  Just wondering why it does that - I'm
> thinking it has something to do with removing the ZPP call for PHP 7 and
> using the (mostly undocumented?) Z_PARAM_ZVAL_EX() macro.  However,
> php_do_pcre_match() over in ext/pcre/php_pcre.c calls zval_dtor() on
> subpats but also uses the Z_PARAM_ZVAL_EX() macro in a similar fashion.
> Looking back at PHP 5.6's php_str_replace_common() shows that it
> previously called zval_dtor().  So it might also be a bug of some sort.

zval_dtor() destroys the value; zval_ptr_dtor() decrements the refcount,
and destroys the value only if the refcount has dropped to 0.  See also
<http://www.phpinternalsbook.com/zvals/memory_management.html> (which is
written for PHP 5, but is still useful).

In your case, zval_dtor() is appropriate, as the zval has already been
separated (ZPP's /), so there can't be other references.

-- 
Christoph M. Becker