Re: [boost] make_shared_array

Subject: Re: [boost] make_shared_array
From: Glen Fernandes (glen.fernandes_at_[hidden])
Date: 2012-11-01 19:45:59

Hi Nate,

I have desired shared_ptr<T[]> for a while now; if it is considered
appropriate for shared_ptr to support that I would like to help make
that happen. My functions could be provided as just
allocate_shared<T[]> and make_shared<T[]> in that case.

I agree that while named "make_shared_array" and
"allocate_shared_array" they should really return shared_array<T>. I
also like the suggestions Peter had to fix shared_array (e.g. nothrow
construction) and perhaps to allow obtaining a shared_ptr<T> from
shared_array<T>.

Glen

On Thu, Nov 1, 2012 at 10:04 AM, Nathan Crookston
<nathan.crookston_at_[hidden]> wrote:
> Hi Peter & Glen,
>
> On Thu, Nov 1, 2012 at 6:07 AM, Peter Dimov <lists_at_[hidden]> wrote:
>> It makes almost no sense to have a function called make_shared_array that
>> does not, in fact, make a shared_array. On the other hand, Glen posits that
>> some people may prefer to use shared_ptr instead of shared_array in their
>> code for various reasons, one of which is that shared_array's default
>> constructor can throw.
>
> I agree that make_shared_array should return a shared_array.  I would
> much rather see shared_array improved to allow such an allocation
> strategy -- I patch my local copy to have an aliasing constructor & an
> implicit conversion to const.  A non-throwing default constructor
> would be very welcome too.
>
> I don't like the idea of returning shared_ptr due to concerns with
> implicit conversion from derived to base.  Also, the lack of
> operator[] would make such usage unnatural (perhaps Glen uses a
> patched shared_ptr?)
>
> The only way I'd want a shared_ptr returned is if shared_ptr were
> partially specialized like unique_ptr -- i.e., I could write
> shared_ptr<int []>.  (Not to go OT, but would a (presumably large)
> patch with this change be considered?)
>
> Thanks,
> Nate
>
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