On Thu, 2008-07-31 at 14:20 -0500, Michael Marcin wrote:
Daniel Frey wrote:
On Thu, 2008-07-31 at 12:16 -0500, Michael Marcin wrote:
Be sure to check the size of your type with your compiler. Some embedded and DSP compilers in the past made types that derive from operators larger. Although I think that was partially due to a operators bug that was fixed a long time ago.
AFAIK that's not a bug in the operators library, but an inefficiency in the compiler's ABI (the EBO actually, which misses some optimization opportunities for multiply inheritance from empty base classes).
I was referring to http://svn.boost.org/trac/boost/ticket/979 which bit me on a project where we had a fixed-point 3 coordinate vector which had operators which contained a fixed-point types which had operators.
That won't help in Neal's code unless he starts using the base class chaining. Since empty_base only takes T into account (not U if available), Neal's code would still contain the same base class (empty< fixed_pt<int_bits,frac_bits,base_type,error_policy,round_policy> >) multiple times, which might lead to some bloat. Regards, Daniel