Re: AC_SYS_LARGEFILE macro

[Paul Eggert]

> From: "Andrej Borsenkow" <address@hidden>
> Date: Tue, 3 Jul 2001 21:44:58 +0400
> 
> > > From: "Andrej Borsenkow" <address@hidden>
> > > Date: Thu, 28 Jun 2001 13:58:35 +0400
> > >
> > > It checks only for specific option for IRIX and _FILE_OFFSET_BITS and
> > > _LARGE_FILES macros. That is not enough; e.g. on our system:
> > >
> > > address@hidden getconf LFS_CFLAGS
> > > -D_FILE_OFFSET_BITS=64 -D_LONGLONG -Kll64

> The above is bullet proof method; actually, both _LONGLONG and
> -Kll64 are default.

OK.  In that case, the autoconf 2.50 code should work fine on Reliant
UNIX.

> > I used to recommend `getconf LFS_CFLAGS', but I don't do it any more;
> > in practice, it causes more trouble than it cures.  Also, `getconf
> > LFS_CFLAGS' will not be included in the next POSIX standard.
> >
> 
> Ah, that is the argument. Is LFS supported by default then?

Unfortunately not.  The latest POSIX draft does not specify how to
enable or disable LFS, or whether LFS is the default.  Most of the LFS
stuff was purposely omitted.  Only a few LFS things made it into the
draft standard: off the top of my head, these include fseeko, ftello,
FILESIZEBITS, and EOVERFLOW.

_FILE_OFFSET_BITS is not standardized; it just happens to be the
method that (almost) everyone uses to specify large-file support, if
it is optional and normally disabled (which is all that autoconf cares
about).