diff --git a/Include/marshal.h b/Include/marshal.h
index f123093..fc491dd 100644
--- a/Include/marshal.h
+++ b/Include/marshal.h
@@ -7,9 +7,11 @@
 extern "C" {
 #endif
 
-PyAPI_FUNC(void) PyMarshal_WriteLongToFile(long, FILE *);
-PyAPI_FUNC(void) PyMarshal_WriteObjectToFile(PyObject *, FILE *);
-PyAPI_FUNC(PyObject *) PyMarshal_WriteObjectToString(PyObject *);
+#define Py_MARSHAL_VERSION 1
+
+PyAPI_FUNC(void) PyMarshal_WriteLongToFile(long, FILE *, int);
+PyAPI_FUNC(void) PyMarshal_WriteObjectToFile(PyObject *, FILE *, int);
+PyAPI_FUNC(PyObject *) PyMarshal_WriteObjectToString(PyObject *, int);
 
 PyAPI_FUNC(long) PyMarshal_ReadLongFromFile(FILE *);
 PyAPI_FUNC(int) PyMarshal_ReadShortFromFile(FILE *);