There is no difference between descriptors for 64-bit objects and 32-bit objects. When displaying a 64-bit fixed-precision object ( INT64, UINT64, LONG64, ULONG64, or DWORD64) use the I64 flag with %d.
As a rule, use %p to display the new pointer types. This will give their full hexadecimal value.
Performance Tools for Software Developers - printf() format descriptors of 64-bit objects
For more complete information about compiler optimizations, see our Optimization Notice.