diff --git a/compiler/symnot.pas b/compiler/symnot.pas
new file mode 100644
index 0000000000..b99c21cc6b
--- /dev/null
+++ b/compiler/symnot.pas
@@ -0,0 +1,76 @@
+{
+    $Id$
+    Copyright (c) 2002 by Daniel Mantione
+
+    This unit contains support routines for the variable access
+    notifier.
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ ****************************************************************************
+}
+
+unit symnot;
+
+{$i fpcdefs.inc}
+
+interface
+
+uses  cclasses,symbase,symtype;
+
+type  Tnotification_flag=(vn_onread,vn_onwrite);
+      Tnotification_flags=set of Tnotification_flag;
+
+      Tnotification_callback=procedure(not_type:Tnotification_flag;
+                                       symbol:Tsym) of object;
+
+      Tnotification=class(Tlinkedlistitem)
+        flags:Tnotification_flags;
+        callback:Tnotification_callback;
+        id:cardinal;
+        constructor create(Aflags:Tnotification_flags;
+                           Acallback:Tnotification_callback);
+      end;
+
+implementation
+
+var notification_counter:cardinal;
+
+constructor Tnotification.create(Aflags:Tnotification_flags;
+                                 Acallback:Tnotification_callback);
+
+begin
+  inherited create;
+  flags:=Aflags;
+  callback:=Acallback;
+  id:=notification_counter;
+  inc(notification_counter);
+end;
+
+begin
+  notification_counter:=0;
+end.
+
+{
+  $Log$
+  Revision 1.1  2002-09-01 08:04:42  daniel
+   + Added read/write notifications of variables. These will be usefull
+     for providing information for several optimizations. For example
+     the value of the loop variable of a for loop does matter is the
+     variable is read after the for loop, but if it's no longer used
+     or written, it doesn't matter and this can be used to optimize
+     the loop code generation.
+
+}