printf and %llu vs %lu on OS X [duplicate]

Question

Possible Duplicate:
how to printf uint64_t?

Why is it that on my 64-bit Mac (I am using Clang) the uint64_t type is unsigned long long while on 64-bit Ubuntu the uint64_t type is unsigned long?

This makes it very difficult for me to get my printf calls to not give compiler warnings (or indeed even to work) under both environments.

I can try to use macros to try to choose the correct string (#define LU either %llu or %lu, and in the process uglifying the printf strings a bit) but on the Mac I've got a 64-bit word size (so _LP64 would be defined and UINTPTR_MAX != 0xffffffff) and yet it still uses long long for the 64 bit int types.

// printf macro switch (for the uint64_t's)
#if UINTPTR_MAX == 0xffffffff 
   // 32-bit
#  define LU "%llu"
#else 
   // assume 64-bit
   // special case for OS X because it is strange
   // should actually check also for __MACH__ 
#  ifdef __APPLE__
#    define LU "%llu"
#  else
#    define LU "%lu"
#  endif
#endif

Answer 1

The macros are already defined for you in <cinttypes>. Try

printf("%"PRIu64, x);

Or, even better, use C++ features like

std::cout << x;

which will select the proper << operator for your variable type.

Answer 2

The answer is to promote via static cast:

some_type i = 5;
printf("our value is: %llu", (unsigned long long)i);