Re: what does regex depend on sys_wait?

[Eric Blake]

On 09/28/2010 01:33 PM, Bruno Haible wrote:
> Eric Blake wrote:
> > Hmm - this would be the first time that one of our replacement headers
> > #includes a non-replacement header
>
> I agree that we shouldn't go this route. libunistring installs the gnulib-
> created variants of stdint.h and stdbool.h in public locations (under different
> names); I think some of Simon's packages do the same.
>
> Thinking more _why_ should<stdlib.h>  declare WIFEXITED etc. at all? Most
> programs I've seen include<sys/wait.h>  for this purpose. The answer is that
> <stdlib.h>  declares the system() function and WIFEXITED etc. are useful for
> analyzing its return code.
>
> So my proposal would be
>    - Introduce a new module 'system', that provides all a user needs for using
>      the system() function according to POSIX.
>    - Make dependencies  system ->  stdlib
>                         system ->  sys_wait
>      but not            stdlib ->  sys_wait.
>    - Change<stdlib.h>  so that it #include<sys/wait.h>  only when the 'system'
>      module has been requested.

Also seems like a reasonable solution to me.

>         New module 'system'.
>         * modules/system: New file.
>         * lib/stdlib.in.h: Include<sys/wait.h>  only when the 'system' module
>         is present.

It doesn't hurt to unconditionally include <sys/wait.h> when WEXITSTATUS 
is undefined; it's just that we can't guarantee that including 
<sys/wait.h> will define WEXITSTATUS unless sys_wait is also in use 
(which it will be if the system module is in use).

>         * m4/stdlib_h.m4 (gl_STDLIB_H_DEFAULTS): Initialize GNULIB_SYSTEM.
>         * modules/stdlib (Depends-on): Remove sys_wait.
>         (Makefile.am): Substitute GNULIB_SYSTEM.
>         * doc/posix-functions/system.texi: Mention the new module.
>         * doc/posix-headers/stdlib.texi: Likewise.
>         Reported by Sam Steingold<address@hidden>.

Missing a change to tests/test-stdlib.c to not test the system()-related 
macros unless the GNULIB_SYSTEM indicator is set.

> +++ lib/stdlib.in.h     Tue Sep 28 21:24:54 2010
> @@ -39,7 +39,7 @@
>   #include<stddef.h>
>
>   /* MirBSD 10 defines WEXITSTATUS in<sys/wait.h>, not in<stdlib.h>.  */
> -#ifndef WEXITSTATUS
> +#if @GNULIB_SYSTEM@&&  !defined WEXITSTATUS
>   # include<sys/wait.h>
>   #endif

So I'm not convinced we need this hunk.

--
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org