Michael Shepanski wrote:
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.
And FWIW my solution works in practice.. specifically in your case, which is the first and only case reported so far. So if I where you, I would just implement it into your version of the code.. (If you don't know how let me know and I'll do it) HTH -- Fernando Cacciola SciSoft http://fcacciola.50webs.com/