Hello again. I'd like to reawaken this thread because It didn't seem to reach a conclusion, and the bug that started it continues to cause me pain. On 10/29/05, Fernando Cacciola <fernando_cacciola@hotmail.com> wrote:
As Martin Bonner suggested, one solution is to factorize the result of alignment_of<> so it returns not just any multiple. Unfortunately, we can't say that the alignment _ought_ to be a power of 2 can we?
An alternative solution that, at least, would work with this very specific example, is to compute it as the minimun of sizeof(charT)-sizeof(T) and sizeof(Tchar)-sizeof(T) That is, adding the char both before and after, and taking the least difference.
These both sound like interesting solutions; what do others think? Are they theoretically correct? A policy question: what happens if no theoretically correct solution is found? Would boost::optional then be discontinued? Or would it be reimplemented in a way that happens to work on all popular platforms? Or would it switch at compile-time between overtly platform-specific implementations? I do hope that the policy is not to keep the current solution until a theoretically correct solution is comes to light. Not to put too fine a point on it, the current solution is theoretically incorrect too; the only thing that distinguishes it from other theoretically incorrect solutions that have been discussed is that this one fails in practice. --- Michael Shepanski