Re: Yet Another Container: DynamicArray

From: Glen Fernandes (glen.fernandes_at_[hidden])
Date: 2020-01-29 04:56:29

On Tue, Jan 28, 2020 at 10:51 PM Gavin Lambert via Boost
<boost_at_[hidden]> wrote:
>
> On 25/01/2020 01:21, Glen Fernandes wrote:
> > Heap storage, fixed size at runtime:
> >     allocate_unique<T[]>(alloc, size, ...)
> >
> >   Gives users everything they need for buffers. (They don't need a Container
> > that is copyable).
>
> Not quite.  These keep the storage pointer and the storage size
> separately,

Yes quite. i.e. What you believe is not true boost::allocate_unique.

i.e. For auto p = boost::allocate_unique<T[]>(a, n);
     assert(p.get().size() == n);

This is because the unique_ptr stores a pointer adaptor around the
Allocator::pointer which also stores the size.

So the pointer and size are stored together in the unique_ptr result.

To get the plain Allocator::pointer out of it you can use p.get().ptr()

Or, for example,   p.release().ptr() for someone who wants to manage
it themselves.

Glen