note 79521 added to function.preg-match

Here's a nice workaround to check if your regex is valid. Sometimes PHP may throw an error like: Warning: preg_match() [function.preg-match]: Unknown modifier '$' in foo.php on line 2 You can't really tell if the 'false' value is actually a value returned because the rule isn't value, or because you regex rule doesn't really match your string. To find out what is the deal with your regex rule (maybe you're building it on fly, etc), you can find out if the "false" returned result is really coming because the string doesn't match, or because a warning was issued. For the last part, I like to use try... catch expressions, so it's highly recommended, let's have a look: <?php function testMyRule($rule, $string) { // don't forget to enable warning reporting if disabled try { /* catch the preg match output warning, inside buffer */ ob_start(); // start bufffer $result = serialize(preg_match($rule, $string)); $pwarnings = ob_get_contents(); // get results, including the warning if any ob_end_clean(); // clean output if (strpos($pwarnings, 'Warning')) { // is warning? throw new Exception($pwarnings); } return unserialize($result); // } catch(Exception $e) { echo $e->getMessage(); die(); } } // end of function ?> Now, you have to make sure error reporting will allow warnings, and next, we'll serialize the result of your preg_match function applied against your string. If this issues a warning, we catch inside the buffer, and later see if the buffer contains the warning. We're serializing/unserializing the result of our pregmatch, because if we wouldn't serialize it, it would come back as a string, instead of boolean. Enjoy! Vladimir Ghetau ---- Server IP: 193.95.141.37 Probable Submitter: 89.101.121.46 ---- Manual Page -- http://www.php.net/manual/en/function.preg-match.php Edit -- https://master.php.net/note/edit/79521 Del: integrated -- https://master.php.net/note/delete/79521/integrated Del: useless -- https://master.php.net/note/delete/79521/useless Del: bad code -- https://master.php.net/note/delete/79521/bad+code Del: spam -- https://master.php.net/note/delete/79521/spam Del: non-english -- https://master.php.net/note/delete/79521/non-english Del: in docs -- https://master.php.net/note/delete/79521/in+docs Del: other reasons-- https://master.php.net/note/delete/79521 Reject -- https://master.php.net/note/reject/79521 Search -- https://master.php.net/manage/user-notes.php