When I #include in multiple files and compile them with the Digital Mars compiler, its linker complains about multiple definitions of an object called ignore. The problem is in the file boost/tuple/detail/tuple_basic.hpp, which has this line: detail::swallow_assign const ignore = detail::swallow_assign(); This works when I compile with gcc or the Microsoft compiler, but it shouldn't be there, should it? I thought the only things with external linkage that should go in headers are special cases like inline functions. If I'm wrong and this is a bug in the Digital Mars compiler or linker let me know and I will go report it. Thanks, Mike Benfield