The template parameter may be something else then "float", "double" or "long double"? If no then I think the documentation should state it clear and it seems to me that it does not at all. (From what I recall specification of std::complex for example explicitely prohibits other specializations then those three types.) Why all functions take parameter T as "T const&" even in specialization and not boost::call_traits<T>::param_type which would be most probably (so I susppect) non reference type? Adam Badura