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Re: AC_COMPUTE_INT's arguments
From: |
Ralf Wildenhues |
Subject: |
Re: AC_COMPUTE_INT's arguments |
Date: |
Mon, 4 Sep 2006 19:12:29 +0200 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Hello Stepan,
* Stepan Kasal wrote on Mon, Sep 04, 2006 at 06:30:19PM CEST:
> On Sun, Sep 03, 2006 at 10:00:08AM +0200, Ralf Wildenhues wrote:
> > * Stepan Kasal wrote on Sat, Sep 02, 2006 at 02:41:48PM CEST:
> > > On Sat, Sep 02, 2006 at 12:09:49PM +0200, Ralf Wildenhues wrote:
> > >
> > > > But that public version would have to include the cast to long int,
> > > > for the HP compiler, which would be at least a bit ugly.
> > >
> > > Ralf, could you please give me a reference to the problem?
> >
> > See the comment in the implementation of AC_CHECK_SIZEOF.
>
> Well, it only says that `sizeof(foo) >= 0' has problems.
Yes, but I noticed the issue with AC_CHECK_ALIGNOF as well.
http://lists.gnu.org/archive/html/autoconf-patches/2006-03/msg00006.html
Also, see the more verbose description in autoconf.info(Specific
Compiler Characteristics). And more indication that this bug (or these
bugs; it's not clear to me there was just one) is of different nature:
http://lists.gnu.org/archive/html/autoconf-patches/2002-02/msg00001.html
http://lists.gnu.org/archive/html/autoconf-patches/2001-10/msg00087.html
Unfortunately (well, not really ;-), it seems the compiler I have access
to has recently been upgraded and does not have this bug any more.
(FWIW, I haven't tried HP testdrive compilers.)
> I do not see what workaround is needed for `sizeof (ptrdiff_t) <=
> sizeof (int)', if any. Perhaps
> (long int) sizeof (ptrdiff_t) <= (long int) sizeof (int) ?
> I do not think that we want
> (long int) (sizeof (ptrdiff_t) <= sizeof (int))
Actually, why not? (This is an honest question!)
> Anyway, I would suggest to modify ptrdiff_max.m4 to use
> AC_LANG_BOOL_COMPILE_IFELSE([sizeof (ptrdiff_t) <= sizeof (int)])
> and wait for a bug report.
I'd definitely object this suggestion.
Cheers,
Ralf