On Visual Studio.NET / VC7.1 the following code: #include <boost/mpl/long.hpp> #include <climits> boost::mpl::long_<LONG_MAX> lll; Gives the following warning: ...\boost_1_32_0\boost\mpl\aux_\integral_wrapper.hpp(72) : warning C4307: '+' : integral constant overflow ...\main.cpp(39) : see reference to class template instantiation 'boost::mpl::long_<N>' being compiled with [ N=2147483647 ] Obviously, the compiler is right about the overflow, and, IMHO, the same holds for using any maximal/minimal value for a specific type. Is this a known issue? Does it cause any actual problems? (in other words: can I ignore the warning? always? sometimes? never?) Thanks, Yariv Tal.