Re: macOS 12.6.3, static_assert, and vasnprintf compilation failure

[Alejandro Colomar]

Hi Bruno and Branden,

On 2/7/23 15:13, Bruno Haible wrote:
> G. Branden Robinson wrote:
> > groff's had an assert.h header
> > since version 1.01 (1991), but I don't know why.  In 2020 I expanded it
> > to support C99-style assertions (i.e., assertions that communicate
> > meaning instead of the nearly useless form from C89).  I am trying to
> > not require C99 features; we can do without variable-length arrays and
> > complex numbers.  But as a developer I insist on C99 assertions.
>
> The Gnulib manual [1] explains that Gnulib essentially assumes C99
> already. I still have access to a machine with a pre-C99 compiler,
> but I don't use it for testing any more, since there's no point in
> using a 20-years old compiler that would barf on 50% of the source
> files.

+1

I suggest declaring C89 a unsupported language version, and requiring a minimum 
of C99 (if not C11).  I worked on upgrading shadow-utils recently from C89 to 
C11, so I may help if you need some help.

<https://github.com/shadow-maint/shadow/issues/600>

> We haven't tested the behaviour of <assert.h> in detail, but you're
> *very* likely to get the C99 assertions that you want everywhere.
>
> > might require #include_next
>
> Note that #include_next requires GCC or clang. So it is much more
> of a portability constraint than merely requiring C99 or newer.
>
> Therefore:
>    - How about removing groff's src/include/assert.h and just rely
>      on the one from the system?

+1

>    - If that does not work out, how about putting the src/include/assert.h
>      into a different directory and adjust the -I options, so that
>      the Gnulib compilation units will not see it? Only the groff C++ code
>      would see it.

Yep, I suggest using src/include/groff/ as a root for all groff includes, and 
use -I src/include, so that you need to include groff's headers as "groff/...", 
which can't collide with anything else.

Cheers,

Alex

> Bruno
>
> [1] 
> <https://www.gnu.org/software/gnulib/manual/html_node/Portability-guidelines.html>

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