diff --git a/src/internal/ntapi_impl.h b/src/internal/ntapi_impl.h
index eb24dee..2c2d162 100644
--- a/src/internal/ntapi_impl.h
+++ b/src/internal/ntapi_impl.h
@@ -131,9 +131,9 @@ union __ntapi_img_rdata {
 
 
 /* accessor table */
-extern	ntapi_vtbl	___ntapi;
-extern	ntapi_vtbl	___ntapi_shadow;
-#define	__ntapi		(&___ntapi)
+extern	__attr_protected__ ntapi_vtbl   ___ntapi;
+extern	__attr_protected__ ntapi_vtbl   ___ntapi_shadow;
+#define	__ntapi                         (&___ntapi)
 
 
 /* access to library internals */