note 116773 added to regexp.reference.delimiters

Note that bracket style opening and closing delimiters aren't a 100% problem-free solution, as they need to be escaped when they aren't in matching pairs within the expression. That mismatch can happen when they appear inside character classes [...], as most meta-characters lose their special meaning. Consider these examples: <?php preg_match('{[{]}', ''); // Warning: preg_match(): No ending matching delimiter '}' preg_match('{[}]}', ''); // Warning: preg_match(): Unknown modifier ']' preg_match('{[}{]}', ''); // Warning: preg_match(): Unknown modifier ']' ?> Escaping them solves it: <?php preg_match('{[\{]}', ''); // OK preg_match('{[}]}', ''); // OK preg_match('{[\}\{]}', ''); // OK ?> ---- Server IP: 72.55.140.6 Probable Submitter: 178.217.187.39 ---- Manual Page -- http://php.net/manual/en/regexp.reference.delimiters.php Edit -- https://master.php.net/note/edit/116773 Del: integrated -- https://master.php.net/note/delete/116773/integrated Del: useless -- https://master.php.net/note/delete/116773/useless Del: bad code -- https://master.php.net/note/delete/116773/bad+code Del: spam -- https://master.php.net/note/delete/116773/spam Del: non-english -- https://master.php.net/note/delete/116773/non-english Del: in docs -- https://master.php.net/note/delete/116773/in+docs Del: other reasons-- https://master.php.net/note/delete/116773 Reject -- https://master.php.net/note/reject/116773 Search -- https://master.php.net/manage/user-notes.php