That will cause a different linker error.
(multiple definitions instead of undefined symbol)

It takes a bit of magic to define these in a header.
BOOST_UNITS_STATIC_CONSTANT handles it, but it only
works at namespace scope. The only to to define
them inside the class and keep it header only, is
to turn A into a template.

Okay. I'll just define them outside the class in the classes namespace. I'd rather keep the header only implementation than get the static defines in the class.

Thanks again for the help.

Ryan