Convert a unicode String In C++ To Upper Case

Question

How we can convert a multi language string or unicode string to upper/lower case in C or C++.

Answer 1

With quite a lot of difficulty if you're going to do it right.

The usual use-case for this is for comparison purposes, but the problem is more general than that.

There is a fairly detailed paper from C++ Report circa 2000 from Matt Austern here (PDF)