diff --git a/dlls/devenum/devenum_private.h b/dlls/devenum/devenum_private.h
index 4f1442386ef..347aebb9081 100644
--- a/dlls/devenum/devenum_private.h
+++ b/dlls/devenum/devenum_private.h
@@ -82,8 +82,8 @@ HRESULT DEVENUM_GetCategoryKey(REFCLSID clsidDeviceClass, HKEY *pBaseKey, WCHAR
 /**********************************************************************
  * Global string constant declarations
  */
-extern const WCHAR clsid_keyname[6];
-extern const WCHAR wszInstanceKeyName[];
+extern const WCHAR clsid_keyname[6] DECLSPEC_HIDDEN;
+extern const WCHAR wszInstanceKeyName[] DECLSPEC_HIDDEN;
 #define CLSID_STR_LEN (sizeof(clsid_keyname) / sizeof(WCHAR))
 
 /**********************************************************************