Re: [Boost-users] [review][fixed_string] FixedString review starts today

From: Zach Laine (whatwasthataddress_at_[hidden])
Date: 2019-12-02 17:38:45

On Thu, Nov 28, 2019 at 6:18 PM Andrey Semashev via Boost <
boost_at_[hidden]> wrote:

> On 2019-11-29 01:44, Zach Laine via Boost wrote:
> >
> > Ok, I understand your point a bit better now I think.  Is it the
> > unboundedly-large nature of a NTBS that has you concerned?  That is, do
> you
> > think that op+=(char) should assert and op+=(char const *) should throw?
> > That position makes sense to me, thought I don't share it -- though I
> think
> > that's just taste.  However, I cannot imagine why I'd ever want
> op+=(char)
> > or op+=(string_view) to throw.
>
> IIRC, append/insert/push_back will throw with any container or
> std::string, if the result exceeds max_size(). It is only natural if
> fixed_string does the same, it is the expected behavior.
>
> You can argue for a separate set of unsafe insert methods that don't
> perform the check and exhibit undefined behavior if the resulting length
> exceeds the limit. But it should be very clear that the user must ensure
> himself that it doesn't happen.
>

I don't find it natural that a type whose size is statically known and a
type whose size is not statically known have the same relationship to user
code (preconditions, use of UB vs. exceptions, etc.).

Zach