swap_in_place<big>(data);
This swap_in_place is a no-op if native is big.
A no-op in what respect? I (might) give you that there will be no observable state change. But from a runtime perspective, I don't agree. However, there is a much bigger problem with all of the examples using copy, please see point 25.2.1 bullet 3 below from the C++ standard: 25.2.1 Copy [lib.alg.copy] template<class InputIterator, class OutputIterator> OutputIterator copy(InputIterator first, InputIterator last, OutputIterator result); 1 Effects: Copies elements in the range [first, last) into the range [result, result + (last - first)) starting from first and proceeding to last. For each non-negative integer n < (last-first), performs *(result + n) = *(first + n). 2 Returns: result + (last - first). *3 Requires: result shall not be in the range [first, last).* Unless I am missing something, I don't see why you are implementing swap_in_place *on top* of the endian types. That just seems backwards to me (other than being illegal) Is there a fundamental design issue you can see by implementing the endian types on top of the functional primitives? Tom