Hi out there We have got folowing problem: ------------------------------------------------------ ***TcpEndpoint.h*** ... #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> class TcpEndpoint : public I_Endpoint { ... }; #include <boost/serialization/export.hpp> BOOST_CLASS_EXPORT_GUID(RCF::TcpEndpoint, "RCF::TcpEndpoint") ------------------------------------------------------- ------------------------------------------------------ ***a.cpp*** ... #include "./TcpEndpoint.hpp" ... ------------------------------------------------------ ***b.cpp*** ... #include "./TcpEndpoint.hpp" ... ------------------------------------------------------ ***c.cpp*** ... #include "./TcpEndpoint.hpp" ... the result of the linker is: b.o(.bss+0x7b): multiple definition of `boost::archive::detail::guid_initializer<RCF::TcpEndpoint>::instance' a.o(.bss+0x0): first defined here c.o(.bss+0x7b): multiple definition of `boost::archive::detail::guid_initializer<RCF::TcpEndpoint>::instance' a.o(.bss+0x0): first defined here In our structure we ave ONE file containing ALL "BOOST_CLASS_EXPORT_GUID" for derived classes and that works fine till the third party lib also has the BOOST_CLASS_EXPORT_GUID macro inside. All in all we want to have someting like that: "A.h" #inlcude "archive_files_and_export.h" class A : public Base {}; BOOST_CLASS_EXPORT_GUID(A, "A") "B.h" #inlcude "archive_files_and_export.h" class B : public Base {}; BOOST_CLASS_EXPORT_GUID(B, "B") "C.h" #inlcude "archive_files_and_export.h" class C : public Base {}; BOOST_CLASS_EXPORT_GUID(C, "C") "main.cpp" #inlcude "A.h" #inlcude "B.h" #inlcude "C.h" int main() {...} ______________________________________ iRMB - Institute for Computational Modeling in Civil Engineering TU Braunschweig Pockelsstr. 3 (9th Floor) D-38106, Braunschweig, Germany phone +49 531/391-7595 fax +49 531/391-7599 email freud@irmb.tu-bs.de <mailto:freud@irmb.tu-bs.de> web www.irmb.tu-bs.de <http://www.irmb.tu-bs.de/>