search for: 0x1234567890ull

share/compat.h contains the following code: /* adjust for compilers that can't understand using LLU suffix for uint64_t literals */ #ifdef _MSC_VER #define FLAC__U64L(x) x #else #define FLAC__U64L(x) x##LLU #endif I tested MSVS 2005 and indeed it doesn't support LLU suffix, but it can compile a code with ULL suffix. Also, http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html mentions ?ULL?