Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(revision 72598)
+++ Modules/posixmodule.c	(working copy)
@@ -568,21 +568,31 @@
 		return PyErr_SetFromWindowsErr(errno);
 }
 
+/* Functions suitable for O$ conversion */
 static int
-convert_to_unicode(PyObject **param)
+convert_to_unicode(PyObject *arg, void* _param)
 {
-	if (PyUnicode_CheckExact(*param))
-		Py_INCREF(*param);
-	else if (PyUnicode_Check(*param))
-		/* For a Unicode subtype that's not a Unicode object,
-		   return a true Unicode object with the same data. */
-		*param = PyUnicode_FromUnicode(PyUnicode_AS_UNICODE(*param),
-					       PyUnicode_GET_SIZE(*param));
-	else
-		*param = PyUnicode_FromEncodedObject(*param,
-				                     Py_FileSystemDefaultEncoding,
-					             "strict");
-	return (*param) != NULL;
+	PyObject **param = (PyObject**)_param;
+	if (arg) {
+		if (PyUnicode_CheckExact(arg)) {
+			Py_INCREF(arg);
+			*param = arg;
+		} 
+		else if (PyUnicode_Check(arg))
+			/* For a Unicode subtype that's not a Unicode object,
+			   return a true Unicode object with the same data. */
+			*param = PyUnicode_FromUnicode(PyUnicode_AS_UNICODE(arg),
+						       PyUnicode_GET_SIZE(arg));
+		else
+			*param = PyUnicode_FromEncodedObject(arg,
+					                     Py_FileSystemDefaultEncoding,
+						             "strict");
+		return (*param) != NULL;
+	}
+	else {
+		Py_DECREF(*param);
+		return 1;
+	}
 }
 
 #endif /* Py_WIN_WIDE_FILENAMES */
@@ -2648,26 +2658,22 @@
 	char *p1, *p2;
 	BOOL result;
 	if (unicode_file_names()) {
-	    if (!PyArg_ParseTuple(args, "OO:rename", &o1, &o2))
-		goto error;
-	    if (!convert_to_unicode(&o1))
-		goto error;
-	    if (!convert_to_unicode(&o2)) {
-		Py_DECREF(o1);
-		goto error;
+	    if (!PyArg_ParseTuple(args, "O$O$:rename", 
+		convert_to_unicode, &o1,
+		convert_to_unicode, &o2))
+		    PyErr_Clear();
+	    else {
+		    Py_BEGIN_ALLOW_THREADS
+		    result = MoveFileW(PyUnicode_AsUnicode(o1),
+				       PyUnicode_AsUnicode(o2));
+		    Py_END_ALLOW_THREADS
+		    Py_DECREF(o1);
+		    Py_DECREF(o2);
+		    if (!result)
+			    return win32_error("rename", NULL);
+		    Py_INCREF(Py_None);
+		    return Py_None;
 	    }
-	    Py_BEGIN_ALLOW_THREADS
-	    result = MoveFileW(PyUnicode_AsUnicode(o1),
-			       PyUnicode_AsUnicode(o2));
-	    Py_END_ALLOW_THREADS
-	    Py_DECREF(o1);
-	    Py_DECREF(o2);
-	    if (!result)
-		    return win32_error("rename", NULL);
-	    Py_INCREF(Py_None);
-	    return Py_None;
-error:
-	    PyErr_Clear();
 	}
 	if (!PyArg_ParseTuple(args, "ss:rename", &p1, &p2))
 		return NULL;
Index: Python/getargs.c
===================================================================
--- Python/getargs.c	(revision 72598)
+++ Python/getargs.c	(working copy)
@@ -175,7 +175,39 @@
 	return 0;
 }
 
+static void
+cleanup_convert(void *ptr, void *desc)
+{
+	typedef int (*destr_t)(PyObject *, void *);
+	destr_t destr = (destr_t)desc;
+	destr(NULL, ptr);
+}
+
 static int
+addcleanup_convert(void *ptr, PyObject **freelist, int (*destr)(PyObject *, void *))
+{
+	PyObject *cobj;
+	if (!*freelist) {
+		*freelist = PyList_New(0);
+		if (!*freelist) {
+			destr(NULL, ptr);
+			return -1;
+		}
+	}
+	cobj = PyCObject_FromVoidPtrAndDesc(ptr, destr, cleanup_convert);
+	if (!cobj) {
+		destr(NULL, ptr);
+		return -1;
+	}
+	if (PyList_Append(*freelist, cobj)) {
+		Py_DECREF(cobj);
+		return -1;
+	}
+        Py_DECREF(cobj);
+	return 0;
+}
+
+static int
 cleanreturn(int retval, PyObject *freelist)
 {
 	if (freelist && retval != 0) {
@@ -1208,6 +1240,18 @@
 				return converterr("(unspecified)", 
 						  arg, msgbuf, bufsize);
 		}
+		else if (*format == '$') {
+			typedef int (*converter)(PyObject *, void *);
+			converter convert = va_arg(*p_va, converter);
+			void *addr = va_arg(*p_va, void *);
+			format++;
+			if (! (*convert)(arg, addr))
+				return converterr("(unspecified)", 
+						  arg, msgbuf, bufsize);
+			if (addcleanup_convert(addr, freelist, convert))
+				return converterr("(cleanup problem)",
+						arg, msgbuf, bufsize);
+		}
 		else {
 			p = va_arg(*p_va, PyObject **);
 			*p = arg;