diff --git a/include/mapival.h b/include/mapival.h
index 2a653a3..82cd020 100644
--- a/include/mapival.h
+++ b/include/mapival.h
@@ -24,6 +24,8 @@
 #endif
 
 #include <mapiutil.h>
+#include <stddef.h>
+#include <stdarg.h>
 
 BOOL  WINAPI FBadRglpszW(LPWSTR*,ULONG);
 BOOL  WINAPI FBadRowSet(LPSRowSet);