Re: [boost] Noexcept

Subject: Re: [boost] Noexcept
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2017-06-14 06:07:34

Le 14/06/2017 à 00:05, Emil Dotchevski via Boost a écrit :
> On Tue, Jun 13, 2017 at 1:01 PM, Bjorn Reese via Boost <
> boost_at_[hidden]> wrote:
>
>> On 06/13/2017 12:38 AM, Emil Dotchevski via Boost wrote:
>>
>> I'll spell it out: Noexcept + optional<> ≈ Outcome
>> That approximation only holds for function-calling scenarios. As I
>> pointed out in my review, there are other use cases for Outcome.
>> Noexcept is a bad match for these use cases, because it transports
>> errors "out-of-band" like errno.
>>
>> One use case is to pass a value-or-error between threads. We already
>> have one outcome-like feature for this: promise-future. If we want to
>> use a different mechanism to pass the value-or-error between threads,
>> then Outcome offers a natural solution.
>>
>> Another use case is to pass a value-or-error via a queue. The queue
>> may contain several outstanding errors. In the case of Outcome, we
>> simply push the value-or-error directly to the queue.
>
> Yes, though I consider this a separate issue. One is, what's the best way
> to transport errors across error-neutral functions within a single thread,
> the other is what to do when, somewhere way up the stack, we get a
> successful value or an error. At that point it's trivial to build a
> variant<T,std::exception_ptr> or equivalent, you don't need a lib for that.
>
+1

Vicente