Re: Bug in largefile.m4

[Paul Eggert]

> Date: Wed, 6 Dec 2000 01:00:49 +0100 (MET)
> From: Joerg Schilling <address@hidden>

> >AC_SYS_LARGEFILE does not support mixed-mode compilation where some
> >bits of code in an application use 32-bit file offsets while other
> >bits of code use 64-bit file offsets.  The whole point of
> >AC_SYS_LARGEFILE is to avoid using mixed-mode, as it is a maintenance
> >nightmare.
> 
> The question would be if it is supported on all platforms.

I think that most platforms that support large-file code also support
mixed-mode code, at least in theory.  However, the mixed-mode stuff is
far less tested in practice, and I'd be leery of using it.

> You are right in one point: If someone finds out that he could compile
> cdrtools as 64 bit sparc binary by just calling 
> 
>       make  COPTX=-xarch=v9 LDOPTX=-xarch=v9
> 
> or if soneone would create a FS that supports largefiles on Linux/aplha

How about Tru64 on Alpha?  Or NetBSD on Alpha?  Not every platform has
a compilation mode where 'long' is 32 bits.

> I would indeed need to check _all_ files for being smaller than 2G.

Yes, I think you have to do that for portability.  There's really not
much choice.  And it's not that hard to do it correctly.

> For a first approach it would be OK to make just the output file large.

That way lies madness.  (But it's your funeral.  :-)