IIRC the attitude was that the "ASCII" versions of functions largely existed only for backwards compatibility, after all on NT[1] they're basically just wrapper

IIRC the attitude was that the "ASCII" versions of functions largely existed only for backwards compatibility, after all on NT[1] they're basically just wrappers that do character set conversion before passing through to the real Unicode (UCS2/UTF16) functions. The view was that if you want Unicode, you should use the real functions directly, which means 16 bit strings. I think there was also some compatibility concerns, as Windows for a while only had a single global "ASCII" character set used by all apps[2], so you'd have issues with actual legacy apps expecting a real legacy code page breaking / having scrambled text if you tried to use UTF8 as the "legacy" encoding. Or the fun idea of an app that is clever enough to know that multibyte exists, but dumb enough to know they can only be one or two bytes long, and allocating buffers accordingly. I think there might have been some issues with how things like the clipboard handled text as well that assumed all "ASCII" apps used the same encoding. (Disclaimed: old memories of reading blogs, may be bollocks). At some point things must have been fixed so multiple character sets could be used though. [1] But not on 9x, which was "ASCII" only, at least until late in the day when a Unicode compatibility library was created. [2] The "Language for non-Unicode programs" as the Control Panel calls it.