I was in this module anyway, so I did some janitorial things.

METH_NOARGS functions are still called with two arguments, one NULL,
so put that back into the function definitions (I didn't know this
until recently).

Make get_history_length() METH_NOARGS.

Modules/readline.c

@@ -150,11 +150,9 @@ history truncation.");
 /* Get history length */
 
 static PyObject*
-get_history_length(PyObject *self, PyObject *args)
+get_history_length(PyObject *self, PyObject *noarg)
 {
-	if (!PyArg_ParseTuple(args, ":get_history_length"))
-		return NULL;
-	return Py_BuildValue("i", history_length);
+	return PyInt_FromLong(history_length);
 }
 
 PyDoc_STRVAR(get_history_length_doc,
@@ -255,7 +253,7 @@ static PyObject *endidx = NULL;
 /* Get the beginning index for the scope of the tab-completion */
 
 static PyObject *
-get_begidx(PyObject *self)
+get_begidx(PyObject *self, PyObject *noarg)
 {
 	Py_INCREF(begidx);
 	return begidx;
@@ -269,7 +267,7 @@ get the beginning index of the readline tab-completion scope");
 /* Get the ending index for the scope of the tab-completion */
 
 static PyObject *
-get_endidx(PyObject *self)
+get_endidx(PyObject *self, PyObject *noarg)
 {
 	Py_INCREF(endidx);
 	return endidx;
@@ -324,7 +322,7 @@ add a line to the history buffer");
 /* Get the tab-completion word-delimiters that readline uses */
 
 static PyObject *
-get_completer_delims(PyObject *self)
+get_completer_delims(PyObject *self, PyObject *noarg)
 {
 	return PyString_FromString(rl_completer_word_break_characters);
 }
@@ -392,7 +390,7 @@ return the current contents of history item at index.");
 /* Exported function to get current length of history */
 
 static PyObject *
-get_current_history_length(PyObject *self)
+get_current_history_length(PyObject *self, PyObject *noarg)
 {
 	HISTORY_STATE *hist_st;
 
@@ -408,7 +406,7 @@ return the current (not the maximum) length of history.");
 /* Exported function to read the current line buffer */
 
 static PyObject *
-get_line_buffer(PyObject *self)
+get_line_buffer(PyObject *self, PyObject *noarg)
 {
 	return PyString_FromString(rl_line_buffer);
 }
@@ -439,7 +437,7 @@ Insert text into the command line.");
 /* Redisplay the line buffer */
 
 static PyObject *
-redisplay(PyObject *self)
+redisplay(PyObject *self, PyObject *noarg)
 {
 	rl_redisplay();
 	Py_INCREF(Py_None);
@@ -457,10 +455,9 @@ contents of the line buffer.");
 static struct PyMethodDef readline_methods[] =
 {
 	{"parse_and_bind", parse_and_bind, METH_VARARGS, doc_parse_and_bind},
-	{"get_line_buffer", (PyCFunction)get_line_buffer,
-	 METH_NOARGS, doc_get_line_buffer},
+	{"get_line_buffer", get_line_buffer, METH_NOARGS, doc_get_line_buffer},
 	{"insert_text", insert_text, METH_VARARGS, doc_insert_text},
-	{"redisplay", (PyCFunction)redisplay, METH_NOARGS, doc_redisplay},
+	{"redisplay", redisplay, METH_NOARGS, doc_redisplay},
 	{"read_init_file", read_init_file, METH_VARARGS, doc_read_init_file},
 	{"read_history_file", read_history_file,
 	 METH_VARARGS, doc_read_history_file},
@@ -473,16 +470,16 @@ static struct PyMethodDef readline_methods[] =
  	{"set_history_length", set_history_length,
 	 METH_VARARGS, set_history_length_doc},
  	{"get_history_length", get_history_length,
-	 METH_VARARGS, get_history_length_doc},
+	 METH_NOARGS, get_history_length_doc},
 	{"set_completer", set_completer, METH_VARARGS, doc_set_completer},
 	{"get_completer", get_completer, METH_NOARGS, doc_get_completer},
-	{"get_begidx", (PyCFunction)get_begidx, METH_NOARGS, doc_get_begidx},
-	{"get_endidx", (PyCFunction)get_endidx, METH_NOARGS, doc_get_endidx},
+	{"get_begidx", get_begidx, METH_NOARGS, doc_get_begidx},
+	{"get_endidx", get_endidx, METH_NOARGS, doc_get_endidx},
 
 	{"set_completer_delims", set_completer_delims,
 	 METH_VARARGS, doc_set_completer_delims},
 	{"add_history", py_add_history, METH_VARARGS, doc_add_history},
-	{"get_completer_delims", (PyCFunction)get_completer_delims,
+	{"get_completer_delims", get_completer_delims,
 	 METH_NOARGS, doc_get_completer_delims},
 
 	{"set_startup_hook", set_startup_hook,