PATCH, libiberty: eliminate build warning

[Doug Kwan (關振德)]

If the macro is used before an "else" keyword, would there be a
problem? I would instead do something like:

#define writeerr(s) do {write (STDERR_FILE_NO, s, strlen (s)); } while (0)

-Doug

2009/11/19 Ben Elliston <bje@au1.ibm.com>:
> This patch eliminates a warning in pex-unix.c due to write(3) being
> marked as warn_unused_result on some GNU/Linux distributions.  As the
> coment in pex_child_error says, there is no alternative such as using
> fwrite(3).
>
> Okay for binutils and gcc trunk?
>
> Thanks, Ben
>
> 2009-11-19  Ben Elliston  <bje@au.ibm.com>
>
>        * pex-unix.c (pex_child_error): Define writeerr macro to avoid
>        unused result warnings from write(3) calls.  Undefine writeerr
>        after all uses.
>
> Index: pex-unix.c
> ===================================================================
> RCS file: /cvs/src/src/libiberty/pex-unix.c,v
> retrieving revision 1.14
> diff -u -p -r1.14 pex-unix.c
> --- pex-unix.c  27 Jul 2009 19:01:17 -0000      1.14
> +++ pex-unix.c  19 Nov 2009 10:09:16 -0000
> @@ -368,7 +368,7 @@ static void
>  pex_child_error (struct pex_obj *obj, const char *executable,
>                 const char *errmsg, int err)
>  {
> -#define writeerr(s) (void) write (STDERR_FILE_NO, s, strlen (s))
> +#define writeerr(s) if (write (STDERR_FILE_NO, s, strlen (s))) {}
>   writeerr (obj->pname);
>   writeerr (": error trying to exec '");
>   writeerr (executable);
> @@ -377,6 +377,7 @@ pex_child_error (struct pex_obj *obj, co
>   writeerr (": ");
>   writeerr (xstrerror (err));
>   writeerr ("\n");
> +#undef writeerr
>   _exit (-1);
>  }
>
>
>
>