diff --git a/src/calibre/utils/windows/winutil.c b/src/calibre/utils/windows/winutil.c
index 3a3ae11bdb..6315ab51cb 100644
--- a/src/calibre/utils/windows/winutil.c
+++ b/src/calibre/utils/windows/winutil.c
@@ -446,19 +446,19 @@ be a unicode string. Returns unicode strings."
         "move_file()\n\nRename the specified file."
     },
 
-    {"add_to_recent_docs", (PyCFunction)add_to_recent_docs, METH_VARARGS,
+    {"add_to_recent_docs", (PyCFunction)winutil_add_to_recent_docs, METH_VARARGS,
         "add_to_recent_docs()\n\nAdd a path to the recent documents list"
     },
 
-    {"file_association", (PyCFunction)file_association, METH_VARARGS,
+    {"file_association", (PyCFunction)winutil_file_association, METH_VARARGS,
         "file_association()\n\nGet the executable associated with the given file extension"
     },
 
-    {"friendly_name", (PyCFunction)friendly_name, METH_VARARGS,
+    {"friendly_name", (PyCFunction)winutil_friendly_name, METH_VARARGS,
         "friendly_name()\n\nGet the friendly name for the specified prog_id/exe"
     },
 
-    {"notify_associations_changed", (PyCFunction)notify_associations_changed, METH_VARARGS,
+    {"notify_associations_changed", (PyCFunction)winutil_notify_associations_changed, METH_VARARGS,
         "notify_associations_changed()\n\nNotify the OS that file associations have changed"
     },
 
diff --git a/src/calibre/utils/windows/winutilpp.cpp b/src/calibre/utils/windows/winutilpp.cpp
index e81fa3d531..1ba43e84e9 100644
--- a/src/calibre/utils/windows/winutilpp.cpp
+++ b/src/calibre/utils/windows/winutilpp.cpp
@@ -14,21 +14,6 @@
 #include <atlbase.h>  // for CComPtr
 #include <Python.h>
 
-static inline int
-py_to_wchar(PyObject *obj, wchar_t **output) {
-	if (!PyUnicode_Check(obj)) {
-		if (obj == Py_None) { *output = NULL; return 1; }
-		PyErr_SetString(PyExc_TypeError, "unicode object expected");
-		return 0;
-	}
-#if PY_MAJOR_VERSION < 3
-	*output = PyUnicode_AS_UNICODE(obj);
-#else
-	*output = PyUnicode_AsWideCharString(obj, NULL);
-#endif
-	return 1;
-}
-
 class wchar_raii {
 	private:
 		wchar_t **handle;
@@ -38,7 +23,7 @@ class wchar_raii {
 		wchar_raii & operator=( const wchar_raii & ) ;
 
 	public:
-		wchar_raii(wchar_t **buf) : handle(*buf) {}
+		wchar_raii() : handle(NULL) {}
 
 		~wchar_raii() {
 #if PY_MAJOR_VERSION >= 3
@@ -48,15 +33,30 @@ class wchar_raii {
 		}
 
 		wchar_t *ptr() { return *handle; }
+		void set_ptr(wchar_t **val) { handle = val; }
 };
 
+static inline int
+py_to_wchar(PyObject *obj, wchar_raii *output) {
+	if (!PyUnicode_Check(obj)) {
+		if (obj == Py_None) { return 1; }
+		PyErr_SetString(PyExc_TypeError, "unicode object expected");
+		return 0;
+	}
+#if PY_MAJOR_VERSION < 3
+	output->set_ptr(&PyUnicode_AS_UNICODE(obj));
+#else
+	output->set_ptr(&PyUnicode_AsWideCharString(obj, NULL));
+#endif
+	return 1;
+}
+
 extern "C" {
 
 PyObject *
 winutil_add_to_recent_docs(PyObject *self, PyObject *args) {
-	wchar_t *path_, *app_id_;
-	if (!PyArg_ParseTuple(args, "O&O&", py_to_wchar, &path_, py_to_wchar, &app_id_)) return NULL;
-	wchar_raii path(path_), app_id(app_id_);
+	wchar_raii path, app_id;
+	if (!PyArg_ParseTuple(args, "O&O&", py_to_wchar, &path, py_to_wchar, &app_id)) return NULL;
 	if (app_id.ptr()) {
 		CComPtr<IShellItem> item;
 		HRESULT hr = SHCreateItemFromParsingName(path.ptr(), NULL, IID_PPV_ARGS(&item));
@@ -75,10 +75,10 @@ winutil_add_to_recent_docs(PyObject *self, PyObject *args) {
 
 PyObject *
 winutil_file_association(PyObject *self, PyObject *args) {
-	wchar_t *ext_, buf[2048];
+	wchar_t buf[2048];
+	wchar_raii ext;
 	DWORD sz = sizeof(buf);
-	if (!PyArg_ParseTuple(args, "O&", py_to_wchar, &ext_)) return NULL;
-	wchar_raii ext(ext_);
+	if (!PyArg_ParseTuple(args, "O&", py_to_wchar, &ext)) return NULL;
 	HRESULT hr = AssocQueryStringW(0, ASSOCSTR_EXECUTABLE, ext.ptr(), NULL, buf, &sz);
 	if (!SUCCEEDED(hr) || sz < 1) Py_RETURN_NONE;
 	return Py_BuildValue("u", buf);
@@ -86,10 +86,10 @@ winutil_file_association(PyObject *self, PyObject *args) {
 
 PyObject *
 winutil_friendly_name(PyObject *self, PyObject *args) {
-	wchar_t *exe_, *prog_id_, buf[2048], *p;
+	wchar_t buf[2048], *p;
+	wchar_raii exe, prog_id;
 	DWORD sz = sizeof(buf);
-	if (!PyArg_ParseTuple(args, "O&O&", py_to_wchar, &prog_id_, py_to_wchar, &exe_)) return NULL;
-	wchar_raii exe(exe_), prog_id(prog_id_);
+	if (!PyArg_ParseTuple(args, "O&O&", py_to_wchar, &prog_id, py_to_wchar, &exe)) return NULL;
 	ASSOCF flags = ASSOCF_REMAPRUNDLL;
 	if (exe.ptr()) {
 		p = exe.ptr();