-Wundef warning in striconveh.h

-Wundef warning in striconveh.h

[Andy Wingo]

Hello,

striconveh.h:22 and striconveh.h:34 use #if when they should use #ifdef,
or something.

Building Guile a contributor got this warning:

  CC     libguile_2.0_la-bytevectors.lo
In file included from bytevectors.c:41:0:
../lib/striconveh.h:22:5: warning: "HAVE_ICONV" is not defined [-Wundef]
In file included from bytevectors.c:41:0:
../lib/striconveh.h:34:5: warning: "HAVE_ICONV" is not defined [-Wundef]

Thanks,

Andy
-- 
http://wingolog.org/

Re: -Wundef warning in striconveh.h

[Eric Blake]

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On 03/17/2011 04:20 AM, Andy Wingo wrote:
> Hello,
> 
> striconveh.h:22 and striconveh.h:34 use #if when they should use #ifdef,
> or something.

Not a bug in gnulib,

> 
> Building Guile a contributor got this warning:

but in guile.  Gnulib specifically documents that -Wundef is
incompatible with gnulib modules, and that our coding style is
deliberate.  -Wundef only catches portability problems for ancient
(non-C89) compilers, and gnulib requires C89 as a bare minimum.  While
you are free to use it for the rest of your project, you need to avoid
it while compiling gnulib (or at least ignore the warnings and avoid
-Werror).

The coreutils project demonstrates how to have two different set of
warning flags appended to AM_CFLAGS: a looser set for the gnulib
subdirectory, and a stricter set for the rest of the project.

-- 
Eric Blake   eblake@redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org


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Re: -Wundef warning in striconveh.h

[Andy Wingo]

Hi Eric,

On Thu 17 Mar 2011 15:05, Eric Blake <eblake@redhat.com> writes:

> On 03/17/2011 04:20 AM, Andy Wingo wrote:
>> striconveh.h:22 and striconveh.h:34 use #if when they should use #ifdef,
>> or something.
>
> Not a bug in gnulib,
>
>> 
>> Building Guile a contributor got this warning:
>
> but in guile.  Gnulib specifically documents that -Wundef is
> incompatible with gnulib modules, and that our coding style is
> deliberate.  -Wundef only catches portability problems for ancient
> (non-C89) compilers, and gnulib requires C89 as a bare minimum.  While
> you are free to use it for the rest of your project, you need to avoid
> it while compiling gnulib (or at least ignore the warnings and avoid
> -Werror).

This error did not occur while compiling gnulib (in the lib/) directory,
but rather libguile, which included striconveh.h.  I believe we already
follow your suggestions for building gnulib itself.

Can you consider changing this one header file?  It does not sound like
an issue on which it is fruitful to be stubborn.

See also this thread also:

  http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/24225

Do you have a response to Ludovic's concerns in his second message?

Regards,

Andy
-- 
http://wingolog.org/

Re: -Wundef warning in striconveh.h

[Paul Eggert]

On 03/17/2011 07:46 AM, Andy Wingo wrote:
> Can you consider changing this one header file?  It does not sound like
> an issue on which it is fruitful to be stubborn.

Well, there is a bit of stubbornness on both sides here, no?  :-)

But I tend to agree: for headers meant to be included by other code,
it's typically better to avoid warnings like that,
when it's easy (which it is here).

Re: -Wundef warning in striconveh.h

[Andy Wingo]

On Thu 17 Mar 2011 17:15, Paul Eggert <eggert@cs.ucla.edu> writes:

> On 03/17/2011 07:46 AM, Andy Wingo wrote:
>> Can you consider changing this one header file?  It does not sound like
>> an issue on which it is fruitful to be stubborn.
>
> Well, there is a bit of stubbornness on both sides here, no?  :-)

Hehe, point taken.  I wouldn't have bothered you, but my users keep
compiling with that and -Werror... they are the stubborn ones! :)

Cheers,

Andy
-- 
http://wingolog.org/

Re: -Wundef warning in striconveh.h

[Ludovic Courtès]

Hello,

Andy Wingo <wingo@pobox.com> writes:

> On Thu 17 Mar 2011 15:05, Eric Blake <eblake@redhat.com> writes:
>
>> On 03/17/2011 04:20 AM, Andy Wingo wrote:
>>> striconveh.h:22 and striconveh.h:34 use #if when they should use #ifdef,
>>> or something.
>>
>> Not a bug in gnulib,
>>
>>> 
>>> Building Guile a contributor got this warning:
>>
>> but in guile.  Gnulib specifically documents that -Wundef is
>> incompatible with gnulib modules, and that our coding style is
>> deliberate.  -Wundef only catches portability problems for ancient
>> (non-C89) compilers, and gnulib requires C89 as a bare minimum.  While
>> you are free to use it for the rest of your project, you need to avoid
>> it while compiling gnulib (or at least ignore the warnings and avoid
>> -Werror).
>
> This error did not occur while compiling gnulib (in the lib/) directory,
> but rather libguile, which included striconveh.h.  I believe we already
> follow your suggestions for building gnulib itself.

[...]

> See also this thread also:
>
>   http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/24225
>
> Do you have a response to Ludovic's concerns in his second message?

Unfortunately <verify.h> now similarly prevents use of -Wundef by its
users (again this happens when compiling libguile; Gnulib itself is
compiled _without_ -Wundef):

  verify.h:177:8: error: "HAVE_STATIC_ASSERT" is not defined [-Werror=undef]

I’m giving up on compiling Guile itself with -Wundef, but I’d prefer it
if Gnulib did not impose its policy on Guile.

Would you be willing to fix the problematic headers?  I’d be happy to
help with that, as I did in the past.

Thanks,
Ludo’.