[Bug 26632] MultiByteToWideChar with MB_ERR_INVALID_CHARS doesn't fail for some code points.

http://bugs.winehq.org/show_bug.cgi?id=26632

--- Comment #4 from Sagawa  2011-04-02 07:55:23 CDT ---
(In reply to comment #3)
> Is it another difference in Microsoft interpretation of Unicode?

Probably yes. Their implementation converts some undefined byte character to
Unicode Private Use Areas (PUA). It is necessary to do round-trip conversion
(e.g. ANSI:0xFF turns into Unicode:U+F8F3, then it should be ANSI:0xFF).

Although that, PUA is not a right place to map because Unicode standards does
not define characters in that area. Thus MB_ERR_INVALID_CHARS flag doesn't
allow to convert to PUA.