Mathias Gaunard wrote:
vicente.botet wrote:
Can someone in this list explain why the standard don't allows to recover the number of elements allocated by new[]? What is the deep reason?
I suppose the reason is to not introduce a distinction between types with destructors and types without.
If this was to be provided, a meta-function to tell whether a type has a trivial destructor or not would be needed as well.
Why? From the underlying allocator point of view there's not much difference in allocating memory for PODs and non-PODs. My guess is that this is not possible in order to allow trivial implementation of new/delete allocators in terms of malloc/free. The latter don't allow to acquire the size of allocated buffer, so in order to provide this ability for new/delete it would have to add its own header to store the size, which would lead to more extensive memory consumption. It's a pity that malloc/free allocator don't allow buffer size acquisition, especially since the size is most likely stored somehow.