Equip the visitor macro with a virtual dtor.

[ginac.git] / ginac / registrar.h

diff --git a/ginac/registrar.h b/ginac/registrar.h
index 384b0e7917d55b8d574ce55a71c2ea489b54c2df..16f39020d9ec1d1b89834077b8a733de4d78687c 100644 (file)
--- a/ginac/registrar.h
+++ b/ginac/registrar.h
@@ -3,7 +3,7 @@
  *  GiNaC's class registrar (for class basic and all classes derived from it). */
 
 /*
- *  GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2005 Johannes Gutenberg University Mainz, Germany
  *
  *  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
@@ -17,7 +17,7 @@
  *
  *  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
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef __GINAC_REGISTRAR_H__
@@ -113,6 +113,7 @@ public: \
        class visitor { \
        public: \
                virtual void visit(const classname &) = 0; \
+               virtual ~visitor() {}; \
        };
 
 /** Macro for inclusion in the declaration of each registered class.