Re: nullptr vs 0

From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2022-05-28 09:18:24

On Fri, 27 May 2022 at 17:31, Andrey Semashev via Boost wrote:
> On 5/27/22 16:18, Mateusz Loskot via Boost wrote:
> > On Fri, 27 May 2022 at 13:01, Andrey Semashev via Boost wrote:
> >> On 5/27/22 05:14, Emil Dotchevski via Boost wrote:
> >>> On Sun, May 22, 2022 at 3:35 AM Andrey Semashev via Boost wrote:
> >>>> I'd replace 0 with NULL. If the compiler keeps complaining report a
> >>>> compiler bug and suppress the warning with a pragma.
> >>>
> >>> I'm all for disabling useless warnings, but then you can leave 0 in the
> >>> code and not bother with NULL. What are you, a C programmer? :)
> >>
> >> It *is* a useless warning. The code with NULL is explicit enough and
> >> portable, so what is this warning about? That the code is not
> >> C++11-only? I know that, and it's not up to the compiler to tell me that.
> >
> > Even if you compile with -std=c++11 ?
>
> Yes. Because you may be including third-party code that is
> C++03-compatible. Or C. Which is not at all uncommon.
> [...]

Yes, that is often the case. Still, I don't mind receiving the warning,
because it gives me feedback on C++ state of my dependencies
which is useful for variety of reasons (internal policies and conventions).

> Personally, the main project I'm working on outside Boost is C++17. But
> this project uses a lot of third-party libraries written in C and C++,
> some of them C++03, with NULL, auto_ptr and other remnants of the old in
> public headers. And I'm really pissed by compilers when they litter
> output with warnings about stuff being deprecated or "bad style"
> according to whatever guide is popular today among compiler vendors,
> while the code in question actually works as expected. And how am I
> supposed to act on these warnings?

Yes, that is annoying.
I use my proxy headers and sling pragmas to disable them.

> Do I have to rewrite the working libraries according to the new style,
> retest everything, push the changes upstream?
> What if the upstream project is still interested in
> legacy systems that only have access to C++03? Is the amount of effort
> it would take even considered when these warnings are implemented?

I ask those questions myself too and I often end up discussing the matter
with maintainers of my third-parties, and I try to contribute with any
modernisation, if that is sensible and acceptable.

> So my opinion is this: If you can use C++11 or newer and there are
> tangible benefits to it - you are very welcome to do so. But don't force
> the world to do the same.

That is not what I aim or mean.
I just was curious why a compiler feature I consider useful
you seem to consider a bug :-)

Thanks for the explanation.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net