note 109146 added to function.debug-zval-dump

You can return a consistent refcount value for any variable (and it will work in PHP 5.3+ without problems) using the following function. 0 is returned if the variable passed has no references outside itself or the variable doesn't exist (use isset in conjunction with this function if you need to distinguish between the two). <?php /** * Return the reference count of a variable. * Returns 0 if a variable has no reference other than itself or doesn't exist. */ function refcount(&$var) { ob_start(); debug_zval_dump(array(&$var)); return preg_replace("/^.+?refcount\((\d+)\).+$/ms", '$1', substr(ob_get_clean(), 24), 1) - 4; } # Example $a = 34; refcount($a) == 0; $b = &$a; refcount($a) == 1; ?> Using the above function as a dependency, you can determine if two variables reference the same space in memory using another small function: <?php /** * Return whether a and b reference the same memory */ function reference(&$a, &$b) { $d = refcount($b); $e = &$a; return refcount($b) != $d; } # Example $a = 3; $b = 5; $c = &$a; $d = &$c; reference($a, $b) == false; reference($a, $c) == true; reference($a, $d) == true; ?> ---- Server IP: 192.41.42.26 Probable Submitter: 76.25.105.79 ---- Manual Page -- http://www.php.net/manual/en/function.debug-zval-dump.php Edit -- https://master.php.net/note/edit/109146 Del: integrated -- https://master.php.net/note/delete/109146/integrated Del: useless -- https://master.php.net/note/delete/109146/useless Del: bad code -- https://master.php.net/note/delete/109146/bad+code Del: spam -- https://master.php.net/note/delete/109146/spam Del: non-english -- https://master.php.net/note/delete/109146/non-english Del: in docs -- https://master.php.net/note/delete/109146/in+docs Del: other reasons-- https://master.php.net/note/delete/109146 Reject -- https://master.php.net/note/reject/109146 Search -- https://master.php.net/manage/user-notes.php