note 119650 added to function.strlen

When checking for length to make sure a value will fit in a database field, be mindful of using the right function. There are three possible situations: 1. Most likely case: the database column is UTF-8 with a length defined in unicode code points (e.g. mysql varchar(200) for a utf-8 database). <?php // ok if php.ini default_charset set to UTF-8 (= default value) mb_strlen($value); iconv_strlen($value); // always ok mb_strlen($value, "UTF-8"); iconv_strlen($value, "UTF-8"); // BAD, do not use: strlen(utf8_decode($value)); // breaks for some multi-byte characters grapheme_strlen($value); // counts graphemes, not code points ?> 2. The database column has a length defined in bytes (e.g. oracle's VARCHAR2(200 BYTE)) <?php // ok, but assumes mbstring.func_overload is 0 in php.ini (= default value) strlen($value); // ok, forces count in bytes mb_strlen($value, "8bit") ?> 3. The database column is in another character set (UTF-16, ISO-8859-1, etc...) with a length defined in characters / code points. Find the character set used, and pass it explicitly to the length function. <?php // ok, supported charsets: http://php.net/manual/en/mbstring.supported-encodings.php mb_strlen($value, $charset); // ok, supported charsets: https://www.gnu.org/software/libiconv/ iconv_strlen($value, $charset); ?> ---- Server IP: 72.52.91.14 Probable Submitter: 81.246.42.197 ---- Manual Page -- http://php.net/manual/en/function.strlen.php Edit -- https://master.php.net/note/edit/119650 Del: integrated -- https://master.php.net/note/delete/119650/integrated Del: useless -- https://master.php.net/note/delete/119650/useless Del: bad code -- https://master.php.net/note/delete/119650/bad+code Del: spam -- https://master.php.net/note/delete/119650/spam Del: non-english -- https://master.php.net/note/delete/119650/non-english Del: in docs -- https://master.php.net/note/delete/119650/in+docs Del: other reasons-- https://master.php.net/note/delete/119650 Reject -- https://master.php.net/note/reject/119650 Search -- https://master.php.net/manage/user-notes.php