note 98843 added to function.preg-replace

If you're using preg_replace() on huge strings you have to be aware of PREG's limitations. In fact, after each preg_xxx() function you should check if PREG internally failed (and by "failure" I don't mean regexp syntax errors). On default PHP installations you will run into problems when using preg_xxx() functions on strings with a length of more than 100'000 characters. To workaround rare occasions you can use this: <?php $iSet= 0; // Count how many times we increase the limit while( $iSet< 10 ) { // If the default limit is 100'000 characters the highest new limit will be 250'000 characters $sNewText= preg_replace( $sRegExpPattern, $sRegExpReplacement, $sVeryLongText ); // Try to use PREG if( preg_last_error()== PREG_BACKTRACK_LIMIT_ERROR ) { // Only check on backtrack limit failure ini_set( 'pcre.backtrack_limit', (int)ini_get( 'pcre.backtrack_limit' )+ 15000 ); // Get current limit and increase $iSet++; // Do not overkill the server } else { // No fail $sVeryLongText= $sNewText; // On failure $sNewText would be NULL break; // Exit loop } } ?> However, be careful: 1.) ini_set() may be forbidden on your server; 2.) preg_last_error() doest not exist prior to PHP 5.2.0; 3.) setting a backtrack limit too high may crash PHP (not only the script currently executed). So if you work a lot with long strings you definitly have to look out for a real solution! See also natedubya's comment (02-Oct-2009 04:08). ---- Server IP: 85.214.154.209 Probable Submitter: 85.180.154.82 ---- Manual Page -- http://www.php.net/manual/en/function.preg-replace.php Edit -- https://master.php.net/note/edit/98843 Del: integrated -- https://master.php.net/note/delete/98843/integrated Del: useless -- https://master.php.net/note/delete/98843/useless Del: bad code -- https://master.php.net/note/delete/98843/bad+code Del: spam -- https://master.php.net/note/delete/98843/spam Del: non-english -- https://master.php.net/note/delete/98843/non-english Del: in docs -- https://master.php.net/note/delete/98843/in+docs Del: other reasons-- https://master.php.net/note/delete/98843 Reject -- https://master.php.net/note/reject/98843 Search -- https://master.php.net/manage/user-notes.php