Ok, it's not a "bug"... but it's damn annoying to get compiler warnings from library header. Especially when those compiler warnings are 1 page long. Is it possible to please not mention variables that aren't being used? This is what I get for a SINGLE warning: /usr/include/boost/archive/detail/interface_oarchive.hpp: In instantiation of ‘const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::interface_oarchive<Archive>::register_type(T*) [with T = std::set, Archive = boost::archive::xml_oarchive]’: /usr/include/boost/archive/detail/oserializer.hpp:332: instantiated from ‘static const boost::archive::detail::basic_pointer_oserializer* boost:: archive::detail::save_pointer_type::non_abstract<T>:: register_type(Archive&) [with T = std::set, Archive = boost::archive::xml_oarchive, TPtr = DirTrees*]’ /usr/include/boost/archive/detail/oserializer.hpp:349: instantiated from ‘static const boost::archive::detail::basic_pointer_oserializer* boost:: archive::detail::save_pointer_type::register_type(Archive&, T&) [with T = std::set

, Archive = boost::archive::xml_oarchive, TPtr = DirTrees*]’ /usr/include/boost/archive/detail/oserializer.hpp:475: instantiated from ‘static void boost::archive::detail::save_pointer_type:: invoke(Archive&, TPtr) [with Archive = boost::archive::xml_oarchive, TPtr = DirTrees*]’ /usr/include/boost/archive/detail/oserializer.hpp:551: instantiated from ‘void boost::archive::save(Archive&, const T&) [with Archive = boost:: archive::xml_oarchive, T = DirTrees*]’ /usr/include/boost/archive/basic_xml_oarchive.hpp:84: instantiated from ‘void boost::archive::basic_xml_oarchive<Archive>::save_override(const boost::serialization::nvp<T>&, int) [with T = DirTrees* const, Archive = boost::archive::xml_oarchive]’ /usr/include/boost/archive/detail/interface_oarchive.hpp:80: instantiated from ‘Archive& boost::archive::detail::interface_oarchive<Archive>:: operator<<(const T&) [with T = boost::serialization::nvp, Archive = boost::archive::xml_oarchive]’ ../../cppgraph/src/serialization.h:35: instantiated from ‘void Iterator<Container>::save(Archive&, unsigned int) const [with Archive = boost::archive::xml_oarchive, Container = DirTrees]’ /usr/include/boost/serialization/access.hpp:90: instantiated from ‘static void boost::serialization::access::member_save(Archive&, const T&, unsigned int) [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ /usr/include/boost/serialization/split_member.hpp:42: instantiated from ‘static void boost::serialization::detail::member_saver::invoke( Archive&, const T&, unsigned int) [with Archive = boost::archive:: xml_oarchive, T = Iterator<DirTrees>]’ /usr/include/boost/serialization/split_member.hpp:63: instantiated from ‘void boost::serialization::split_member(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ ../../cppgraph/src/serialization.h:46: instantiated from ‘void Iterator<Container>::serialize(Archive&, unsigned int) [with Archive = boost::archive::xml_oarchive, Container = DirTrees]’ /usr/include/boost/serialization/access.hpp:106: instantiated from ‘static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ /usr/include/boost/serialization/serialization.hpp:78: instantiated from ‘void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ /usr/include/boost/serialization/serialization.hpp:121: instantiated from ‘void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ /usr/include/boost/archive/detail/oserializer.hpp:148: instantiated from ‘void boost::archive::detail::oserializer::save_object_data (boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::xml_oarchive, T = Iterator<DirTrees>]’ ../../cppgraph/src/serialization.cc:40: instantiated from here /usr/include/boost/archive/detail/interface_oarchive.hpp:60: warning: unused parameter ‘t’

Moreover, I normally treat warnings as errors (with -Werror); which is impossible when a third party library generates warnings. -- Carlo Wood