Index: interface_oarchive.hpp
===================================================================
RCS file: /cvsroot/boost/boost/boost/archive/detail/interface_oarchive.hpp,v
retrieving revision 1.10
diff -u -r1.10 interface_oarchive.hpp
--- interface_oarchive.hpp	21 Apr 2005 04:52:45 -0000	1.10
+++ interface_oarchive.hpp	6 May 2005 09:11:21 -0000
@@ -72,7 +72,7 @@
     }
 
     template<class T>
-    Archive & operator<<(T & t){
+    Archive & operator<<(const T & t){
         this->This()->save_override(t, 0);
         return * this->This();
     }