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Subject: Re: Are Exceptions deeply flawed?
From: Dmitry (dimanne_at_[hidden])
Date: 2019-08-07 15:10:19


>
> I really don't want to create temporary files anymore, since that implies
> removing them at some point. So I really need memfds. So I can't do your
> first
> point.
>
What will you do if this feature is not available (your program is running
on older kernel)?

> Sorry, you don't get to change the API. Using the API as-is was the big
> problem of your post. If you can change my API to make it better and
> report a
> more structured set of information, then the same can be done too for
> exceptions.

That is really interesting and that is what I cannot fully understand, can
you please elaborate how exactly it can be done via exceptions? Of course,
in a maintainable way (a way that can easily accommodate adding/removing
sub-errors *as well as adding new direct/indirect callers* of the function
in the future), without relying on documentation nor on comments etc...?

>
> Your solution requires that at some point in the call stack, the error
> condition be consumed and then either augmented or handled. Nothing in
> that
> requires using return values, global/thread-local values (like errno) or
> exceptions. All three are possible.
>
All three are possible, not all of them are as visible and explicit as
return-values.

> What you're arguing for is sanely designed API and handling error
> conditions
> as close to the error locus as possible. I don't dispute that: that's the
> proper and only way to handle errors. What I will agree with you is that
> using
> exceptions makes it to easy *not* to do it, since you can simply "forget"
> to
> handle, then let the error pass on to your caller. When using return
> values,
> the error condition will often be "in your face" and you'll have a hard
> time
> ignoring it.
>
> But C++ does not dictate what you must do. You don't like exceptions? Or
> don't
> feel comfortable writing code with it, like me? Then don't use them. But
> don't
> ask that they be removed from the language. That's not going to happen.
>

Yes, I, probably, agree with you.
But, should not then exceptions be discouraged from using exactly as

   - bare new/malloc (in favour of make_unique/make_shared)
   - or void * (in favour of type-rich programming)
   - or default implicit constructors

are discouraged now?

Even if the answer is no, should not we add expected<> (for symmetry or as
mechanism that complEments exceptions) into the standard?



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