Hi, I'm trying to make a custom archive class that works either with the template flavor or via the polymorphic_archive. It compiles but produces a different behavior and I can't find why. Basically I did a trivial oarchive class that overloads (via save_override) how are treated NVP. When used with the template version it works, whereas with the polymorphic version it doesn't. The code is attached. There is a preprocessor switch to choose the template or polymorphic version (-DPOLY). $ g++ poly.cc -lboost_serialization && ./a.out <name=u><name=id_>42</name=id_> </name=u> $ g++ -DPOLY poly.cc -lboost_serialization && ./a.out 42 This is with Boost 1.43 and g++ 4.5.0. I looked at various archive implementations but couldn't find any code that I could relate to this problem. Thanks, -- Maxime