-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
According to Russ Allbery on 3/22/2009 1:18 PM:
> Currently, this is done with:
>
> AC_FUNC_FSEEKO
> if test x"$ac_cv_func_fseeko" != xyes ; then
> INN_TYPE_FPOS_T_LARGE
> AC_CHECK_DECLS([fseeko, ftello])
> AC_LIBOBJ([fseeko])
> AC_LIBOBJ([ftello])
> fi
>
> This stopped working with recent Autoconf (I think around 2.62, but I
> could be wrong). AC_FUNC_FSEEKO used to set ac_cv_func_fseeko but
> stopped; now ac_cv_sys_largefile_source is set instead (and not to
> something as simple as yes or no).
AC_FUNC_FSEEKO was rewritten for 2.61, but a typo rendered it broken in
that release, so it didn't work again until 2.62.
>
> This is exactly why I hate relying on cache variables. :)
Relying on documented cache variables is fine. But you are correct that
relying on undocumented cache variables tends to be problematic.
>
> Could AC_FUNC_FSEEKO acquire ACTION_IF_FOUND and ACTION_IF_NOT_FOUND
> arguments so that I can implement this conditional probing and AC_LIBOBJ
> calls in a sane fashion without relying on undocumented and unsupported
> macro internals?
Why not ditch AC_FUNC_FSEEKO, and write a portable variant yourself?
AC_DEFUN([INN_FSEEKO],
[AC_REQUIRE([AC_SYS_LARGEFILE])dnl
AC_CACHE_CHECK([for fseeko], [inn_cv_func_fseeko],
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <sys/types.h> /* for off_t */
#include <stdio.h>
]], [[int (*fp) (FILE *, off_t, int) = fseeko;
return fseeko (stdin, 0, 0) && fp (stdin, 0, 0);]])]
[inn_cv_func_fseeko=yes], [inn_cv_func_fseeko=no])])
if test x"$inn_cv_func_fseeko" != xyes ; then
INN_TYPE_FPOS_T_LARGE
AC_CHECK_DECLS([fseeko, ftello])
AC_LIBOBJ([fseeko])
AC_LIBOBJ([ftello])
fi
])
That said, if others agree with you that exporting ac_cv_func_fseeko for
compatibility is still worthwhile (it was dropped in commit 90fcd46
autoconf 2.60a-37), then we could probably modify AC_FUNC_FSEEKO to once
again set that variable to yes or no for 2.64 and beyond.
- --
Don't work too hard, make some time for fun as well!
Eric Blake ebb9@xxxxxxx
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
iEYEARECAAYFAknHbh8ACgkQ84KuGfSFAYA6OwCfeVoku0/b2IEcg8rVqY8Ha6zW
Mr8AoKx/OPW3jJJ5t4xsHZr1wk3wyE6b
=iKXx
-----END PGP SIGNATURE-----
_______________________________________________
Autoconf mailing list
Autoconf@xxxxxxx
http://lists.gnu.org/mailman/listinfo/autoconf
