* added GUID_NULL constant

git-svn-id: trunk@13236 -

rtl/objpas/sysutils/intfh.inc

@@ -20,6 +20,9 @@
     System Utilities For Free Pascal
 }
 
+const
+  GUID_NULL: TGuid = '{00000000-0000-0000-0000-000000000000}';
+
 function Supports(const Instance: IInterface; const IID: TGUID; out Intf): Boolean; overload;
 function Supports(const Instance: TObject; const IID: TGUID; out Intf): Boolean; overload;
 function Supports(const Instance: TObject; const IID: Shortstring; out Intf): Boolean; overload;