Re: [boost] Reference counting 'any'

From: Peter Dimov (pdimov_at_[hidden])
Date: 2001-07-20 07:52:44

From: "Corwin Joy" <cjoy_at_[hidden]>
> Given that the original 'any' class provided const only access, I think it
> would be interesting to hear what the compelling argument was for adding
> non-const access to the 'any' class in the first place.

Did it?

Anyway, I have one question to Kevlin:

Why is a copy-on-write 'any' implementation non-conforming? What (single
threaded) valid user program does not work with a COW implementation?

[Note: the current spec does not specify the validity of the pointer
returned by any_cast. Therefore it should be interpreted to be valid until
the next 'any' operation. I think that this can be strengthened to 'the next
non-const operation' and a COW implementation would still conform.]

--
Peter Dimov
Multi Media Ltd.