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

[Jason Rumney <jasonr@gnu.org>]

Joakim Hårsman <joakim.harsman@gmail.com> writes:

>>
>>   +/* Set text of w32 frame with handle HWND to TEXT.
>>   +
>>   +   We explicitly switch between the Unicode and ANSI version of
>>   +   SetWindowText because Emacs isn't compiled with UNICODE defined to
>>   +   retain compatibility with Windows 95. */
>>   +
>>   +static void
>>   +w32_set_frame_text (HWND hwnd, LPCSTR text)
>>   +{
>>   +  if (os_subtype == OS_NT)
>>   +    SetWindowTextW (hwnd, (LPCWSTR)text);
>>   +  else
>>   +    SetWindowTextA (hwnd, text);
>>   +}

> The change to SetWindowTextW for frame titles was needed because
> otherwise the frame title was cut short after the first character
> (presumably because the window class name is a UCS-2 wide string and
> the second byte therefore is null). This is exaclty the case they talk
> about at your link.

>>          if (STRING_MULTIBYTE (name))
>>   -       name = ENCODE_SYSTEM (name);
>>   -
>>   +        name = ENCODE_SYSTEM (name);
>>   +
>>          BLOCK_INPUT;
>>   -      SetWindowText (FRAME_W32_WINDOW (f), SDATA (name));
>>   +      w32_set_frame_text(FRAME_W32_WINDOW (f), SDATA (name));

But the above doesn't pass a UCS-2 wide string to SetWindowTextW.  It
passes an 8-bit string encoded in the system 8-bit encoding, then simply
casts it to a wchar_t!  You cannot possibly get the correct frame title using
this patch.