I recently tried some simple tests of the Boost date-time library (Boost 1.30.0 MSVC6) and ran into problems. I don't have the original code in front of me (unfortunately I left it at work), but more or less, it looked like this: #include "boost/date_time/gregorian/gregorian.hpp" #include <iostream> int main() { using namespace boost::gregorian; date today = day_clock::local_day(); month_iterator it(today); std::advance(it, 3); std::string strDate(to_simple_string(*it)); std::cout << "New date is " << strDate << std::endl; return 0; } The first problem I ran into was that I got a linker error because the class greg_month (in greg_month.hpp) did not provide definitions for the following member functions: const char* as_short_string() const; const char* as_long_string() const; I quicky wrote some inline switch statements to get past that hurdle, but then the compiler started complaining when I tried to use std::advance. It is unfortunate that I do not have the exact error in front of me right now, but I did trace the problem to the definition of month_iterator. I found that if I derived its base implementation class from the class template iterator that it would compile without problems. Is this a problem with the STL that ships with MSVC6? Anyway, I was wondering if maybe there was something I had not set up correctly with my compiler that was causing me to get these errors. Any help would be appreciated. Carl Waldbieser waldbie(at-sign-goes-here)attglobal.net