Interesting. I am unaware of the impossibility of it. The only complaints I know of with detecting architecture through macros is having to modify the code for each architecture (ala detail/limits.hpp). It is not the best in the world, but that is mostly because of the maintenance issues.
Agreed.
1 2 3 4 4 3 2 1 2 1 4 3 3 4 1 2
Of the above, I only know of three that are actually in use, and the third (3412) has not been around since the early PDP machines. Of course, I am not familiar with all architectures.
OK could be more theoretical then (except on itanium apparently!)
Again, I think the possibilities outstrip reality, and reality is the only thing that counts here... as long as each architecture has a specific #define that can be detected at compile time. The worst thing is that a particular architecture may not be supported, and a #error can be issued.
I imagine architectures are consistent themselves, but something like this would help if that were necessary:
#if defined(__i386__) #define BOOST_BYTEORDER_16 12 #define BOOST_BYTEORDER_32 1234 #define BOOST_BYTEORDER_64 12345678 #elif defined(__sparc__) #define BOOST_BYTEORDER_16 21 #define BOOST_BYTEORDER_32 4321 #define BOOST_BYTEORDER_64 87654321 #elif defined(__dinosaur__) #define BOOST_BYTEORDER_16 21 #define BOOST_BYTEORDER_32 4321 #define BOOST_BYTEORDER_64 87654321 #else #error Byte ordering undetected #endif
That's an even worse maintenance nightmare; at some point there's a cost-benefit trade-off to be made here. John.