For int64_t type:
int64_t
int64_t t; printf("%"PRId64" ", t);
for uint64_t type:
uint64_t
uint64_t t; printf("%"PRIu64" ", t);
you can also use PRIx64 to print in hexadecimal.
PRIx64
These macros are defined in inttypes.h
inttypes.h