Re: no-c++

[Sam Steingold]

On Mon, Aug 10, 2009 at 10:12 AM, Simon Josefsson<address@hidden> wrote:
> Sam Steingold <address@hidden> writes:
>
>> Some packages are compilable with both C (production) and C++ (extra
>> compilation time type checking and run-time verification for
>> debugging).
>> when such a package uses code from gnulib, it wants to compile it with
>> the compiler ($(CC)) it uses for the rest of the package, i.e., when
>> compiling with CC=C, it compiles the imported gnulib code with C, ahen
>> compiling with CC=C++, it compiles the imported gnulib code with with
>> C++.
>> when the imported gnulib code cannot be compiled with C++ (e.g.,
>> regexp), this causes problems.
>
> I don't see how CC=c++ would ever work generally as C and C++ are
> different languages.

well, they are similar enough that their common part, if you wish
(i.e., the code that would compile with both) is large enough for a
package to be written in.
after all C++ was designed as an extension to C, i.e., originally it
was a superset thereof.

> Instead of CC=c++, why not use a configure parameter like
> --with-cxx-compiler that makes the project build the parts of the
> project that is known to be compilable as C++ using the system's C++
> compiler, and use a C compiler for the rest (i.e., gnulib code)?  With
> this approach, you can use normal AC_PROG_CXX etc checks for the C++
> stuff and don't have to hack around autoconf/automake.

what is --with-cxx-compiler?
how do I enable it?

>>> Compiling C code with a C++ compiler seems like a good recipe for
>>> problems, and I don't think it is something gnulib should force on users
>>> unless there is a compelling use-case.
>>
>> the "forcing" goes the other way around.
>> the user of gnulib forces C++ on gnulib code, and gnulib should use
>> no-cxx (when necessary) to cope with it.
>
> I don't follow the analogy.  If a user attempts CC=python gnulib will
> break.

I did not know python was designed as a superset of C.

> Is there a wide class of projects or operating systems that recommends
> or suggests use of CC=c++ that I've missed?  I'm trying to understand
> the origins of the CC=c++ notion.  Learning that may help me understand
> the bigger picture.

http://clisp.cons.org/impnotes/gc-safety.html#gc-alloccount

-- 
Sam Steingold <http://sds.podval.org>