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Re: scope guard

From: Andrey Semashev <andrey.semashev_at_[hidden]>
Date: Tue, 3 Aug 2021 16:18:55 +0300
On 8/3/21 4:02 PM, language.lawyer--- via Std-Proposals 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

Ok, it is possible use it with non-pointers. Doesn't mean that's
something you would normally do instead of just writing a dedicated
handle class instead of struggling with unique_ptr.

And scope guards are not just about RAII. Really, the point of a scope
guard is to execute a piece of code. And to achieve that goal the
language could offer a more appropriate syntax. Compare the amount of
code you have to write to employ unique_ptr with something like this:

   scope_exit [&]

where scope_exit would be a keyword. I'm not proposing this particular
syntax, it's just an illustration.

Received on 2021-08-03 08:19:02