[Boost-users] type_with_alignment<5> ?

From: Gottlob Frege (gottlobfrege_at_[hidden])
Date: 2006-06-13 13:59:54

I'd like type_with_alignment<> to handle sizes between 'true' alignments,
and/or have a way to map 'in bwetween' alignments to their lower alignment.

ie I have a struct of unknown type, but known size = 5.  What is it's
alignment?  You could 'punt' and say max_align, but I suggest that its
alignment is <= 5 (ie probably 4 for a typical platform).  ie imagine that
the struct might have an int as it's first member, but can't have a double
(assuming sizeof(double) > 5), so the alignment might need to be
alignment_of<int>, but can't be alignment_of<double>.  Does this assumption
hold true?

So how can I map (at compile time) an integer 'n' to the closest 'x' <= n
where x is from the set S, and where S is the set of possible alignments?

Tony