In Python 2.7, PC/msvcrtmodule.c, the function msvcrt_ungetwch() calls _ungetch() instead of _ungetwch() as was probably intended.

Parsing the argument is also broken:

    static PyObject *
    msvcrt_ungetwch(PyObject *self, PyObject *args)
    {
        Py_UNICODE ch;

        if (!PyArg_ParseTuple(args, "u:ungetwch", &ch))
            return NULL;

        if (_ungetch(ch) == EOF)
            return PyErr_SetFromErrno(PyExc_IOError);
        Py_INCREF(Py_None);
        return Py_None;
    }

Format "u" is a `Py_UNICODE *`. There's no "C" format code in 2.x, so it will first have to check that the string length is exactly 1 and then use index 0.

Uh, you're right.  Then I can also add that putwch() strangely checks for unicode strings of length != 0 instead of == 1, despite what it says it its error message.  These functions appear not to be tested or even (in case of ungetwch()) used by anyone.

Python 2 is EOL, so I think this issue should be closed.

If this isn't an issue in Python 3, I agree.