I had the same problem with vc 7.1.
Strange. I never had problems like this with vc7.1
It's very easy to reproduce the problem. Create project with two source files (e.g. a.cpp and b.cpp) both with the same content: -- begin #include <boost/test/floating_point_comparison.hpp> -- end When you try to compile you get two errors: b.obj : error LNK2005: "struct check_is_small_t::boost::check_is_small_t boost::test_tools::`anonymous namespace'::check_is_small" (?check_is_small@?A0xa003c394@test_tools@boost@@3Ucheck_is_small_t@23@A) already defined in a.obj b.obj : error LNK2005: "struct check_is_close_t::boost::check_is_close_t boost::test_tools::`anonymous namespace'::check_is_close" (?check_is_close@?A0xa003c394@test_tools@boost@@3Ucheck_is_close_t@23@A) already defined in a.obj boost version 1.33.1.
If you add 'static' to all variables definitions in anonymous namespaces it works fine.
But anonimous namespace should do the trick itself!
Agree. Seems like compiler bug to me. Roman.