bug#10299: Emacs doesn't handle Unicode characters in keyboard layout on MS Windows

[Lennart Borgman <lennart.borgman@gmail.com>]

On Mon, Dec 19, 2011 at 11:44, Joakim Hårsman <joakim.harsman@gmail.com> wrote:
> On 18 December 2011 19:13, Eli Zaretskii <eliz@gnu.org> wrote:
>>> Date: Sun, 18 Dec 2011 18:31:55 +0100
>>> From: Joakim Hårsman <joakim.harsman@gmail.com>
>>>
>>> > That's good news.  However, I'm puzzled: are you saying that the code
>>> > points passed by Windows to Emacs for the characters generated by MKLC
>>> > are outside the Unicode BMP, i.e. larger than 65535?  If so, what code
>>> > points are they?
>>>
>>> No, none of the characters I needed are outside the BMP.
>>>
>>> WM_CHAR encodes the codepoint in UTF-16 inside wParam, while
>>> WM_UNICHAR uses UTF-32. So if I press something which gives U+2218
>>> RING OPERATOR, I get a WM_CHAR event with a wParam of 2228248 or
>>> 0x220018.
>>
>> ??? UTF-16 encodes the characters in the BMP as themselves, i.e. a
>> single 16-bit value that is numerically identical to the codepoint.
>> That is, you should have gotten 0x2218.  What am I missing?
>
> I just assumed Windows encoded the codepoints into a DWORD in some
> funky way, but looking more closely at the documentattion it appears
> like wParam should just be the codepoint. Even more strangely, some
> places claim that if a keyboard produces a character outside the BMP,
> you get two WM_CHAR events.
>
> From what I can tell, Emacs itself never alters wParam, but I guess
> Windows might do some funky multibyte encoding since Emacs isn't
> completely Unicode?

Maybe Emacs on windows still is using the ANSI version of DefWindowProc? See

http://blogs.msdn.com/b/michkap/archive/2007/03/25/1945659.aspx