Hi, There appears to be a temperature conversion problem between ºC and ºF. Here's a simple test that shows the error under both gcc and Intel on both Darwin and Linux (with Boost trunk). brisc:~ kbelco$ cat test3.cpp #include <iostream> #include <boost/units/io.hpp> #include <boost/units/quantity.hpp> #include <boost/units/systems/temperature/celsius.hpp> #include <boost/units/systems/temperature/fahrenheit.hpp> int main(int, char **) { using namespace boost::units; quantity<fahrenheit::temperature> t(100 * celsius::temperature()); // expect output of 212 F, produces 180 F // seems like not adding 32º offset when computing F = (C * 9/5 + 32) std::cout << t << std::endl; return 0; } brisc:~ kbelco$ icpc -g -Iboost test3.cpp brisc:~ kbelco$ ./a.out 180 F -- Noel