stdint.h provides various machine-independent integer types that are very
handy to use, especially the
uint64_t family. You would assume it's something
long long unsigned int and tempted to use
printf, which, however, will be
reported as a warning by any decent compiler.
warning: format '%llu' expects argument of type 'long long unsigned int', but argument 4 has type 'uint64_t' [-Wformat]