diff --git a/src/lib/diff/diff-language.hpp b/src/lib/diff/diff-language.hpp
index f0dd090b5..c5f5e06a5 100644
--- a/src/lib/diff/diff-language.hpp
+++ b/src/lib/diff/diff-language.hpp
@@ -97,7 +97,8 @@ namespace diff{
   
   namespace error = lumiera::error;
   
-  LUMIERA_ERROR_DEFINE(DIFF_CONFLICT, "Collision in diff application: contents of target not as expected.");
+  LUMIERA_ERROR_DECLARE(DIFF_CONFLICT); ///< Collision in diff application: contents of target not as expected.
+  
   
   /**
    * Definition frame for a language to describe differences in data structures.
diff --git a/src/lib/diff/diff.cpp b/src/lib/diff/diff.cpp
new file mode 100644
index 000000000..7bc2d54fb
--- /dev/null
+++ b/src/lib/diff/diff.cpp
@@ -0,0 +1,44 @@
+/*
+  Diff  -  common helpers for the diff handling framework
+
+  Copyright (C)         Lumiera.org
+    2015,               Hermann Vosseler <Ichthyostega@web.de>
+
+  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.
+
+* *****************************************************/
+
+
+/** @file diff.cpp
+ ** Diff handling framework support code.
+ ** This translation unit emits code used by the implementation
+ ** of generic functionality
+ ** 
+ ** @see diff-language.hpp
+ ** 
+ */
+
+
+#include "lib/error.hpp"
+#include "lib/diff/diff-language.hpp"
+
+
+namespace lib {
+namespace diff{
+  
+  LUMIERA_ERROR_DEFINE(DIFF_CONFLICT, "Collision in diff application: contents of target not as expected.");
+  
+  
+}} // namespace lib::diff