On Tue, Aug 3, 2021 at 9:03 AM language.lawyer--- via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> On 03/08/2021 15:22, Andrey Semashev via Std-Proposals wrote:
> > On 8/3/21 3:08 PM, Jens Maurer via Std-Proposals wrote:
> >> On 03/08/2021 11.46, Baruch Burstein via Std-Proposals wrote:
> >>> Hi.
> >>> Why is there no generic scope guard in the standard library?
> >>> I am sure there must have been such a proposal before, probably with
> an explanation of why it was not accepted, but I couldn't find it.
> >>
> >> Try std::unique_ptr with a custom deleter.
> >
> > This only works for pointers.
>
> unique_ptr can be used with non-pointers
>
> https://stackoverflow.com/questions/15756960/using-unique-ptr-to-control-a-file-descriptor
>
> https://stackoverflow.com/questions/24611215/one-liner-for-raii-on-non-pointer


Oddly enough, both of those SO links are from people asking "Why can't I
use unique_ptr on non-pointers?" and people in the answers pointing out
that unique_ptr can be used only with pointers (that is, with types that
satisfy the NullablePointer requirements). Notably, if your type isn't
convertible-from `nullptr`, then it can't be wrapped in a unique_ptr
(because unique_ptr works only with pointers).

However, for a generic scope guard, I recommend `Auto`:
https://quuxplusone.github.io/blog/2018/08/11/the-auto-macro/
https://godbolt.org/z/vT6Tfo1YM

–Arthur