diff --git a/Common/HashMap.h b/Common/HashMap.h
new file mode 100644
index 0000000000000000000000000000000000000000..c60241c66ffa26c3dcfd9ac0eb53c678a6f3bec9
--- /dev/null
+++ b/Common/HashMap.h
@@ -0,0 +1,29 @@
+#ifndef _HASH_MAP_H_
+#define _HASH_MAP_H_
+
+// Copyright (C) 1997-2006 C. Geuzaine, J.-F. Remacle
+//
+// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+// USA.
+// 
+// Please report all bugs and problems to <gmsh@geuz.org>.
+
+//--Define custom hash map here.  It must have form <key, value, HashFunctor,
+//--EqualFunctor>
+
+#define HASH_MAP         __gnu_cxx::hash_map
+#include <ext/hash_map>
+
+#endif