From: Evgen Bodunov <evgen@globus.software>
To: libstdc++ <libstdc++@gcc.gnu.org>
Subject: Re: Forward declaration and std::future
Date: Mon, 13 Sep 2021 10:32:59 +0200 [thread overview]
Message-ID: <7E360609-1A07-4A41-8775-6CD46D382067@globus.software> (raw)
In-Reply-To: <CAH6eHdTOWdYcMcHytzjBD68TA-hx10Qh5zwac+2uBipZan6R4g@mail.gmail.com>
> On 12.09.2021, at 22:04, Jonathan Wakely via Libstdc++ <libstdc++@gcc.gnu.org> wrote:
>
> On Sun, 12 Sep 2021, 19:30 Evgen Bodunov, <evgen@globus.software> wrote:
>>
>> Please, could you refer exact part and version of the standard?
>>
>
> Please reply to the mailing list, not just to me.
>
> Every version of the standard has the same requirement, see
> http://eel.is/c++draft/requirements#res.on.functions-2.5
>
> std::promise requires its result type to be destructible. We are allowed to
> assert that by using is_destructible because we can assume the type is
> complete, because [res.on.functions] says it must be.
>
> In a correct program, the assertion will not fail.
Thank you for the detailed response. For some reason I expected that if there is not enough
type data to compile the code correctly, there would be an error from the compiler, not from
static_assert. As for example in case of inheritance or creating objects from a type that was
forward declared. And in this case there is an error saying that the class doesn't have a
destructor, although it actually exists and this is confusing.
next prev parent reply other threads:[~2021-09-13 8:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-12 9:36 Evgen Bodunov
2021-09-12 18:19 ` Jonathan Wakely
[not found] ` <BFCFC341-004F-4FC9-A298-6DFAB390815D@globus.software>
2021-09-12 20:04 ` Jonathan Wakely
2021-09-13 8:32 ` Evgen Bodunov [this message]
2021-09-13 8:52 ` Jonathan Wakely
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