Re: [boost] Noexcept

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@lists.boost.org> wrote:

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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 or equivalent, you don't need a lib for that.

+1 Vicente