systems/si/base.hpp defines specializations of unit_info. there is not declaration of unit_info in any of the files that it directly of indirectly includes.
Michael noticed this too - I've fixed it for the next update.
You might want to switch on BOOST_TYPEOF_NATIVE. That will at least catch compilers that use __typeof__ + msvc while avoiding the possibly expensive registration/lookup mechanism.
I'm not familiar enough with Boost.Typeof to know what that does - is it just a #define somewhere before typeof is called, then replace typeof with BOOST_TYPEOF? Matthias ---------------------------------------------------------------- Matthias Schabel, Ph.D. Assistant Professor, Department of Radiology Utah Center for Advanced Imaging Research 729 Arapeen Drive Salt Lake City, UT 84108 801-587-9413 (work) 801-585-3592 (fax) 801-706-5760 (cell) 801-484-0811 (home) matthias dot schabel at hsc dot utah dot edu ----------------------------------------------------------------