When I try to compile the following code: #include <boost/named_params.hpp> #include <boost/iterator/transform_iterator.hpp> I get: ghost@zigzag:/tmp$ g++ -I ~/Work/boost -I ~/Work/boost-sandbox np.cpp In file included from /home/ghost/Work/boost/boost/iterator/detail/enable_if.hpp:15, from /home/ghost/Work/boost/boost/iterator/transform_iterator.hpp:14, from np.cpp:3: /home/ghost/Work/boost/boost/iterator/detail/config_def.hpp:22:3: #error you have nested config_def #inclusion. I suspect that the attached patch might need to be applied, but since I don't understand 'config_def.hpp' I though I'd ask first. - Volodya