I have read several things about this topic but still I have doubts I want to share with the community.
I want to add a complete utf-8 support to the application I developed, DaDaBIK; the application can be used with different DBMSs (such as MySQL, PostgreSQL, SQLite). The charset used in the databases can be ANY. I cant' set or assume the charset.
My approach would be convert, using iconv functions, everything i read from the db in utf-8 and then convert it back in the original charset when I have to write to the DB. This would allow me to assume I'm working with utf-8.
The problem, as you probably know, is that PHP doesn't support utf-8 natively and, even assuming to use mbstring, there are (according to http://www.phpwact.org/php/i18n/utf-8) several PHP functions which can create problems with utf-8 and DON't have an mbstring correspondance, for example the PREG extension, strcspn, trim, ucfirst, ucwords....
Since I'm using some external libraries such as adodb and htmLawed I can't control all the source code...in those libraries there are several cases of usage of those functions....do you have any advice about? And above all, how very popular applications like wordpress and so on are handling this (IMHO big) problem? I doubt they don't have any "trim" in the code....they just take the risk (data corruption for example) or there is something I can't see?
Thanks a lot.