From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christopher Li <sparse@chrisli.org>
Subject: Re: [PATCH 4/5] Fix some "plain integer as NULL pointer" warnings on
	cygwin
Date: Mon, 20 Jul 2009 13:31:20 -0700
Message-ID: <70318cbf0907201331v1c830779i89c9bef9d6706115@mail.gmail.com>
References: <4A623766.5020002@ramsay1.demon.co.uk>
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To: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Cc: Sparse Mailing-list <linux-sparse@vger.kernel.org>

On Sat, Jul 18, 2009 at 1:58 PM, Ramsay Jones<ramsay@ramsay1.demon.co.u=
k> wrote:
>
> These sparse warnings are caused by broken new-lib headers,
> which sometimes result in NULL being defined as 0, and at
> other times defined as ((void *)0).
>
> In essence, the only header which works correctly (by defining
> NULL as ((void *)0)) is stddef.h. The stdio.h and time.h headers
> also work, almost by accident, by indirectly including stddef.h.
> The other standard headers which are required to define the NULL
> macro, namely locale.h, stdlib.h, string.h and wchar.h, all
> define the macro as the 0 token. (This is a slightly simplified
> description of the problem).
>
> In order to suppress these warnings, include the stddef.h header
> at the start of ptrlist.c.
>
> Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
> ---
>
> Hi Chris,
>
> $ cat -n null-test.sh
> =A0 =A0 1 =A0#!/bin/bash
> =A0 =A0 2
> =A0 =A0 3 =A0# The C99 standard says that the following headers defin=
e NULL:
> =A0 =A0 4 =A0# =A0 locale.h (7.11), stddef.h (7.17), stdio.h (7.19.1)=
,
> =A0 =A0 5 =A0# =A0 stdlib.h (7.20), string.h (7.21.1), time.h (7.23.1=
),
> =A0 =A0 6 =A0# =A0 wchar.h (7.24.1).
> =A0 =A0 7
> =A0 =A0 8 =A0for i in locale.h stddef.h stdio.h stdlib.h string.h tim=
e.h wchar.h
> =A0 =A0 9 =A0do
> =A0 =A010 =A0 =A0 =A0 =A0 =A0printf "%10s: =A0" $i
> =A0 =A011 =A0 =A0 =A0 =A0 =A0printf "#include<%s>\nchar *xyz_ptr =3D =
NULL;\n" $i >t.c
> =A0 =A012 =A0 =A0 =A0 =A0 =A0cgcc -E t.c | grep xyz_ptr
> =A0 =A013 =A0done
> =A0 =A014 =A0rm t.c
> =A0 =A015
> $ ./null-test.sh

That is what I get in FC11:
  locale.h:  char *xyz_ptr =3D ((void *)0);
  stddef.h:  char *xyz_ptr =3D ((void *)0);
   stdio.h:  char *xyz_ptr =3D ((void *)0);
  stdlib.h:  char *xyz_ptr =3D ((void *)0);
  string.h:  char *xyz_ptr =3D ((void *)0);
    time.h:  char *xyz_ptr =3D ((void *)0);
   wchar.h:  char *xyz_ptr =3D ((void *)0);

Which system has this problem?

Chris
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