Re: [PATCH 4/5] Fix some "plain integer as NULL pointer" warnings on cygwin

[Christopher Li <sparse@chrisli.org>]

On Sat, Jul 18, 2009 at 1:58 PM, Ramsay Jones<ramsay@ramsay1.demon.co.uk> 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
>     1  #!/bin/bash
>     2
>     3  # The C99 standard says that the following headers define NULL:
>     4  #   locale.h (7.11), stddef.h (7.17), stdio.h (7.19.1),
>     5  #   stdlib.h (7.20), string.h (7.21.1), time.h (7.23.1),
>     6  #   wchar.h (7.24.1).
>     7
>     8  for i in locale.h stddef.h stdio.h stdlib.h string.h time.h wchar.h
>     9  do
>    10          printf "%10s:  " $i
>    11          printf "#include<%s>\nchar *xyz_ptr = NULL;\n" $i >t.c
>    12          cgcc -E t.c | grep xyz_ptr
>    13  done
>    14  rm t.c
>    15
> $ ./null-test.sh

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

Which system has this problem?

Chris
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