Re: Suggested policy for dropping C++03 support in Boost libraries

From: James E. King III (jking_at_[hidden])
Date: 2019-11-08 03:24:43

On Thu, Nov 7, 2019, 10:13 PM Robert Ramey via Boost <boost_at_[hidden]>
wrote:

> On 11/7/19 6:23 PM, Glen Fernandes via Boost wrote:
> > On Thu, Nov 7, 2019 at 9:09 PM Robert Ramey wrote:
> >>
> >> On 11/7/19 2:27 PM, Peter Dimov via Boost wrote:
> >>> What is being proposed is a sanctioned mechanism for library
> maintainers
> >>> to drop C++03 in an orderly manner. Any library maintainer who wishes
> to
> >>> maintain C++03 support is free to do so.
> >>
> >> I don't see any difference between this and the current policy.  As far
> >> as I know no library developer has ever been required to provide support
> >> for other than the current standard.  Of course if I'm wrong about this,
> >> then feel free to make this policy explicit.  I don't see it changing
> >> anything.
> >
> > It's different in this way: Some Boost authors and contributors do
> > feel constrained even if the official policy is to support only the
> > latest/current standard from breaking either an existing Boost library
> > that depends on that library that supports C++03, or breaking some
> > software that uses that Boost library which must be compiled in C++03.
>
> Hmmm this is a big surprise to me.  My understanding has been that
> anything that would compile with C++03 would be compilable with all the
> subsequent versions of C++.  That is the guarantee of backward
> compatibility.  There has been talk about breaking this guarantee, but
> as far as I know it is still guaranteed.
>
> > For example, during a Boost beta release, reports might come in from
> > users saying that X library no longer works for them because they need
> > C++03 support. Or after a release, a Linux distribution package set
> > fails to build, because they compile those programs in C++03 mode, and
> > the Boost library stops compiling in C++03 mode.
> >
> > But while that might have been the case three - maybe even two - years
> > ago, it isn't likely to be the case now. e.g. More compilers default
> > standard mode is C++14 now, not C++03. i.e. Those of us who were
> > worried about that outcome are less worried about it now.
>
> Hmm - for example, the boost serialization library is C++03 compatible,
> but it compiles with std=C++14 just fine - exactly as guaranteed by the
> standard.
>
> Soooooo - you can make whatever policy you want, but I don't see how it
> would the maintainer of the serialization library in any way.
>
> Robert Ramey
>
> >
> > Glen
> >
> >

This was already debated before.  No need to rehash it.  Maintainers are
already empowered to drop C++03 support.  They can start by updating their
readme and docs and stop running their C++03 CI jobs.

- Jim