Why is "strndup" defined in mkvmi.c?

I'm a co-maintainer of the SWI prolog package on Fedora, and I've been
trouble shooting a problem where the latest 5.7.x versions don't build
properly. The compiler (GCC 4.4.0) doesn't like the declaration of
"strndup" in src/mkvmi.c -- it says:
    mkvmi.c:146: error: static declaration of 'strndup' follows
non-static declaration
The previous compiler (GCC 4.3.2) has no problem with this, so it's
probably something new triggered in the latest version, for what it's
worth.

If I just comment out the declaration of strndup, the compilation
proceeds successfully as far as I can tell. Why is this function there
in the first place, though?

Thanks for any suggestions,

MEF

--
Mary Ellen Foster  --  http://homepages.inf.ed.ac.uk/mef/
ICCS, School of Informatics, University of Edinburgh

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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[Keri Harris-2]

On Sat, 13 Jun 2009 00:54:37 Mary Ellen Foster wrote:

> I'm a co-maintainer of the SWI prolog package on Fedora, and I've been
> trouble shooting a problem where the latest 5.7.x versions don't build
> properly. The compiler (GCC 4.4.0) doesn't like the declaration of
> "strndup" in src/mkvmi.c -- it says:
>     mkvmi.c:146: error: static declaration of 'strndup' follows
> non-static declaration
> The previous compiler (GCC 4.3.2) has no problem with this, so it's
> probably something new triggered in the latest version, for what it's
> worth.
>
> If I just comment out the declaration of strndup, the compilation
> proceeds successfully as far as I can tell. Why is this function there
> in the first place, though?
>
> Thanks for any suggestions,
>
> MEF

Are you using glibc-2.10? That library version contains new POSIX functions
that are essentially "backports" of existing GNU extensions (including
strndup). Now being POSIX functions they're declared to the C compiler even
when _GNU_SOURCE is not defined.

Non-GNU SWI-Prolog builds probably still need a local declaration of strndup.
But it looks like Jan had run across a similar problem in plld.c and solved
it thusly:

commit f1f03ea8cad026bc8f835f333188b5c14e18f986
Author: Jan Wielemaker <wielemak@...>
Date:   Tue Feb 5 09:07:56 2002 +0000

    * Fix name-clash

diff --git a/src/plld.c b/src/plld.c
index a3a5566..9575792 100644
--- a/src/plld.c
+++ b/src/plld.c
@@ -126,6 +126,8 @@ embedded application.
 #define oserror xoserror
 #undef strdup
 #define strdup plld_strdup
+#undef strndup
+#define strndup plld_strndup
 #ifdef HAVE_DMALLOC_H
 #undef xmalloc
 #undef xrealloc





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[Jan Wielemaker-3]

On Friday 12 June 2009 14:54:37 Mary Ellen Foster wrote:

> I'm a co-maintainer of the SWI prolog package on Fedora, and I've been
> trouble shooting a problem where the latest 5.7.x versions don't build
> properly. The compiler (GCC 4.4.0) doesn't like the declaration of
> "strndup" in src/mkvmi.c -- it says:
>     mkvmi.c:146: error: static declaration of 'strndup' follows
> non-static declaration
> The previous compiler (GCC 4.3.2) has no problem with this, so it's
> probably something new triggered in the latest version, for what it's
> worth.
>
> If I just comment out the declaration of strndup, the compilation
> proceeds successfully as far as I can tell. Why is this function there
> in the first place, though?

Not all C-libraries provide it.  I've renamed it into my_strndup().

        Thanks --- Jan

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