SInt64 and UInt64 problems with large values

FROM : Ken Tozier
DATE : Sat Apr 02 11:00:35 2005

In lieu of using "long long" and "unsigned long long" in my code, I'm
trying to use the more compact "SInt64" and "UInt64" both of which the
compiler seems to be aware of , but when I try to give UInt64 a large
constant hex value such as 0xFFFFFFFFFFFFFFFF, the complier complains
that "integer constant is too large for "long" type." I searched for
the definition of UInt64 and found it in MacTypes.h where it is defined
as "typedef unsigned long long UInt64" so why does the compiler not
allow the maximum hex value? Is there some undocumented upper limit to
long long values?

Thanks

Ken