Re: [PATCH 2/2] Include unistd.h.

From: Junio C Hamano <gitster@pobox.com>
Date: May 25, 2011, 21:00 UTC
Message-ID: <7vvcwy1onq.fsf@alter.siamese.dyndns.org>
In-Reply-To: <BANLkTim4gPAyA9vLnpBz7qRY+b4RQ7LwNw@mail.gmail.com>

Tor Arntsen <tor@spacetec.no> writes:

Show 10 quoted lines

> On Wed, May 25, 2011 at 20:30, Junio C Hamano <gitster@pobox.com> wrote:
> ...
>> The header stddef.h is where NULL is supposed to be defined, and commonly
>> used headers are supposed to define NULL the same way as stddef.h does.
>> There is a conditional inclusion of stdlib.h in fnmatch.c and stdlib.h is
>> one of those files; probably that is how the upstream pulls in NULL when
>> compiling this.
>
> According to POSIX (well, IEEE Std 1003.1, 2004 Edition at least)
> unistd.h must define NULL:

Yes, unistd.h is also one of the common header files just like stdlib.h and stdio.h that are required to define NULL the same way as stddef.h does.

Cf.
    http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html

Show 5 quoted lines

>> Other platforms (e.g. SunOS, IRIX, HPUX, Windows) use NO_FNMATCH_CASEFOLD
>> and compile this file.  How are they getting their NULLs?
>
> IRIX defines NULL in ...
> ... presumably it's in some compiler-provided place.

Yes, but that still does not explain where compat/fnmatch/fnmatch.c gets its NULL from.

> #ifndef NULL
> #define NULL 0 /* or sometimes 0L */
> #endif

You probably would want to say "(void *) 0" if you quote POSIX in the same message ;-).

Cf.
    http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html

To recap my original question that is not unanswered, the current codebase does not include unistd.h nor stddef.h when compiling the compatibility fnmatch.c source we borrowed from glibc, but nobody seems to have complained that it does not compile due to the lack of NULL, so they must be getting their NULL from somewhere already, but I couldn't find where. That is what I was wondering.