Re: Interest for C++20 modules support of boost officially

From: Peter Dimov (pdimov_at_[hidden])
Date: 2024-12-22 16:19:48

Ruben Perez wrote:
> > This problem seems to make modules an all or nothing proposition. If
> > one Boost library is a module, everything else also must be. We can't
> > really mix and match modules and includes on a per-library basis as I
> > envisaged. And things would be simplified considerably if we can also
> > extend this to the standard library. It's either both import boost.* and
> import std, or neither.
> 
> What I've written until now assumes exactly this. It may be a lot to assume, but
> if you do need to mix, you can just use headers. I may be completely wrong,
> and mixing includes and imports will become important in the future. It felt
> fair to make this assumption (at least now) because the standard library seems
> to do it, too.

In the general case, the user will have to build all of his dependencies
using a consistent setting of the "use Boost modules" macro, because
otherwise a prebuilt library may well include something Boost.

Which is going to be a problem if that prebuilt library is installed by
a package manager, especially the system package manager.

I suppose that's already a problem a theory, but modules might be
more sensitive to it.