note 107946 added to language.references

There is no built in method (yet) to check if two variables are references to the same piece of data, but you can do a "reference sniff" test. This is rarely needed, but can be very useful. The function bellow is a slightly modified version of this technique I saw in a forum regarding this comparison limitation. <?php function is_ref_to(&$a, &$b) { $t = $a; if($r=($b===($a=1))){ $r = ($b===($a=0)); } $a = $t; return $r; } $varA = 1; $varB = $varA; $varC =&$varA; var_dump( is_ref_to($varA, $varB) ); // bool(false) var_dump( is_ref_to($varA, $varC) ); // bool(true) ?> The test above uses a two step process to be 100% generic. But if you are sure the variables being tested will not be a certain value, example null, then use that value to allow a one step check. <?php function is_ref_to_1step(&$a, &$b) { $t = $a; $r=($b===($a=null)); $a = $t; return $r; } ?> ---- Server IP: 72.55.140.6 Probable Submitter: 69.159.196.196 ---- Manual Page -- http://www.php.net/manual/en/language.references.php Edit -- https://master.php.net/note/edit/107946 Del: integrated -- https://master.php.net/note/delete/107946/integrated Del: useless -- https://master.php.net/note/delete/107946/useless Del: bad code -- https://master.php.net/note/delete/107946/bad+code Del: spam -- https://master.php.net/note/delete/107946/spam Del: non-english -- https://master.php.net/note/delete/107946/non-english Del: in docs -- https://master.php.net/note/delete/107946/in+docs Del: other reasons-- https://master.php.net/note/delete/107946 Reject -- https://master.php.net/note/reject/107946 Search -- https://master.php.net/manage/user-notes.php