Re: [PATCH] ntdll: Fix existing conftests for nanosecond precision time fields.

[Alexandre Julliard]

Charles Davis <cdavis5x(a)gmail.com> writes:
> From: Charles Davis <cdavis(a)mymail.mines.edu>
>
> Autoconf checks for a field of a struct by using it in an if()
> expression. Of course, you can't do this for an aggregate field, so you
> must instead check a field of that aggregate instead. Up until now, the
> conftests for the st_?tim fields were all failing, even on systems that
> had them, because of this.

It does a sizeof, which should work just fine. On what system do you see
a problem?

-- 
Alexandre Julliard
julliard(a)winehq.org

[PATCH] ntdll: Fix existing conftests for nanosecond precision time fields.

[Charles Davis]

On Nov 29, 2012, at 11:47 AM, Alexandre Julliard wrote:
> Charles Davis <cdavis5x(a)gmail.com> writes:
> > From: Charles Davis <cdavis(a)mymail.mines.edu>
> >
> > Autoconf checks for a field of a struct by using it in an if()
> > expression. Of course, you can't do this for an aggregate field, so you
> > must instead check a field of that aggregate instead. Up until now, the
> > conftests for the st_?tim fields were all failing, even on systems that
> > had them, because of this.
>
> It does a sizeof, which should work just fine.
> No it doesn't. This is the conftest.c template that it uses (ac_fn_c_check_member() function, at line 2036 in configure):

<contents of confdefs.h>
/* end confdefs.h.  */
$5
int
main ()
{
static $2 ac_aggr;
if (ac_aggr.$3)
return 0;
  ;
  return 0;
}

I see no sizeof in there.

Chip

[PATCH] ntdll: Fix existing conftests for nanosecond precision time fields.

[Charles Davis]

On Nov 29, 2012, at 2:22 PM, Charles Davis wrote:
> On Nov 29, 2012, at 11:47 AM, Alexandre Julliard wrote:
> > Charles Davis <cdavis5x(a)gmail.com> writes:
> > > From: Charles Davis <cdavis(a)mymail.mines.edu>
> > >
> > > Autoconf checks for a field of a struct by using it in an if()
> > > expression. Of course, you can't do this for an aggregate field, so you
> > > must instead check a field of that aggregate instead. Up until now, the
> > > conftests for the st_?tim fields were all failing, even on systems that
> > > had them, because of this.
> >
> > It does a sizeof, which should work just fine.
> > No it doesn't. This is the conftest.c template that it uses (ac_fn_c_check_member() function, at line 2036 in configure):
>
> <contents of confdefs.h>
> /* end confdefs.h.  */
> $5
> int
> main ()
> {
> static $2 ac_aggr;
> if (ac_aggr.$3)
> return 0;
>  ;
>  return 0;
> }
>
> I see no sizeof in there.

Oh wait... there's the second conftest later on in that function, that does use sizeof. Sorry for the noise. (But I have to wonder why they don't just have one test using sizeof... Autoconf is just one, big horrible hack.)

Chip