[BeeOnRope]

The conclusion near the end of the blog post?

That's not really because performance doesn't matter, but because toupper() shouldn't really matter in most modern C and C++ programs: it just can't support Unicode. So either you are using a different way of supporting strings entirely (if you need any kind of Unicode or multibyte support), or this is some internal ASCII-only text processing in which case you are better off using your own methods (e.g., the lookup table I mention at the end) since they'll provide an easy speedup and you aren't accidentally introducing locale-dependent code where you don't want it.