[Boost-users] Unexpected warning relating to boost::function, and size_t / unsigned

Hello, I'm receiving a compiler warning (MSVC8.0) that does not make sense to me, and I wonder if this might be a boost related issue: #include <vector> #include <functional> #include int main() { std::vector< std::size_t > sizes; std::vector< unsigned > data; boost::function< bool (unsigned, unsigned) > fn = std::greater< unsigned >(); fn( data.front(), 10 ); // NOTE: data is empty - will cause runtime error } The warning I get is: warning C4267: 'argument' : conversion from 'size_t' to 'unsigned int', possible loss of data referring to the last line in main(). This warning goes away if I do either of the following: - Comment out the std::vector< std::size_t > sizes - this one baffles me. - Use a 'naked' std::greater< unsigned >() instead of a boost::function< bool (unsigned, unsigned) >() object. I wonder if size_t is somehow redefined in boost in a way that might be causing me some trouble? Any help would be appreciated, thanks. Matt