diff --git a/src/if_ole.cpp b/src/if_ole.cpp
index aaa3868..0888883 100644
--- a/src/if_ole.cpp
+++ b/src/if_ole.cpp
@@ -759,7 +759,7 @@
     hr = RegisterActiveObject(
 	app,
 	MYCLSID,
-	NULL,
+	0,
 	&app_id);
 
     if (FAILED(hr))