after switching to VC10 I recognized that including the cstdint.hpp header causes a warning. After looking into this header I saw that all defines like INT8_C are guarded to prevent multiple defines, except of the UINT8_C define (cstdint.hpp Line:400). Is this done on purpose because to me it looks as if the guard was just forgotten.

Which Boost version? I just tried: #include <cstdint> #include <boost/cstdint.hpp> with 1.44 and /W4 and saw no warnings, Cheers, John.