loewis> Furthermore, all other uses of the "c" code might 
loewis> need to be reconsidered.

$ grep 'BuildValue.*"c"' */*c
Modules/_cursesmodule.c:    return Py_BuildValue("c", rtn);
Modules/mmapmodule.c:           return Py_BuildValue("c", value);

$ grep '_Parse[^"]\+"[^":;]*c' */*c
Modules/mmapmodule.c:   if (!PyArg_ParseTuple(args, "c:write_byte", 
&value))
PC/msvcrtmodule.c:      if (!PyArg_ParseTuple(args, "c:putch", &ch))
PC/msvcrtmodule.c:      if (!PyArg_ParseTuple(args, "c:ungetch", &ch))

So we have:
* mmap.read_byte()->char, mmap.write_byte(char): should be fixed to 
use bytes
* <curses window>.getkey()->char: it looks correct because the 
function uses also "return PyUnicode_FromString(...);"
* msvcrt.putch(char), msvcrt.ungetch(char): msvcrt has also:
  - msvcrt.getch()->byte string of 1 byte
  - msvcrt.getwch()->unicode string of 1 character
  - msvcrt.putwch(unicode string of 1 character)
  - msvcrt_ungetwch(unicode string of 1 character)
  Hum, putch(), ungetch(), getch() use inconsistent types 
(unicode/bytes) and should be fixed. Another issue should be open for 
that.

Notes: msvcrt.putwch() accepts string of length > 1 and 
msvcrt.ungetwch() doesn't check string length (and so may crash with 
length=0 or length > 1?).