diff --git a/dlls/oledlg/oledlg_private.h b/dlls/oledlg/oledlg_private.h
index 4ff3bb6f9f8526b8fd7264897dfb39c885c4ea2e..8be1d6b3cb69d4098a4bcad9b6a2e4a30862e4f4 100644
--- a/dlls/oledlg/oledlg_private.h
+++ b/dlls/oledlg/oledlg_private.h
@@ -21,18 +21,18 @@
 #ifndef __OLEDLG_PRIVATE_H__
 #define __OLEDLG_PRIVATE_H__
 
-extern HINSTANCE OLEDLG_hInstance;
+extern HINSTANCE OLEDLG_hInstance DECLSPEC_HIDDEN;
 
-extern UINT cf_embed_source;
-extern UINT cf_embedded_object;
-extern UINT cf_link_source;
-extern UINT cf_object_descriptor;
-extern UINT cf_link_src_descriptor;
-extern UINT cf_ownerlink;
-extern UINT cf_filename;
-extern UINT cf_filenamew;
+extern UINT cf_embed_source DECLSPEC_HIDDEN;
+extern UINT cf_embedded_object DECLSPEC_HIDDEN;
+extern UINT cf_link_source DECLSPEC_HIDDEN;
+extern UINT cf_object_descriptor DECLSPEC_HIDDEN;
+extern UINT cf_link_src_descriptor DECLSPEC_HIDDEN;
+extern UINT cf_ownerlink DECLSPEC_HIDDEN;
+extern UINT cf_filename DECLSPEC_HIDDEN;
+extern UINT cf_filenamew DECLSPEC_HIDDEN;
 
-extern UINT oleui_msg_help;
-extern UINT oleui_msg_enddialog;
+extern UINT oleui_msg_help DECLSPEC_HIDDEN;
+extern UINT oleui_msg_enddialog DECLSPEC_HIDDEN;
 
 #endif /* __OLEDLG_PRIVATE_H__ */