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Re: PATCH: Fix __WORDSIZE for ia64.


On Fri, Aug 01, 2003 at 10:37:48AM +0200, Jakub Jelinek wrote:
> On Fri, Aug 01, 2003 at 01:13:33AM -0700, Roland McGrath wrote:
> > > With this change, the only loss is we can no longer access the old utmp
> > > file. I think it is the price we should pay to fix the problem. 
> > 
> > I am inclined to agree with this conclusion (the same one made on other
> > 64/32 platforms).  But it's not a change you just slip in without comment,
> > discussion with users and system maintainers, and approval from the
> > architecture's canonical maintainer.
> 
> There are many programs which access utmp directly and use struct utmp
> or struct lastlog for that (instead of using the libc acess functions).
> Defining __WORDSIZE_COMPAT32 macro on ia64 means you simply abandon
> compatibility with any ia64 programs which ever use utmp/wtmp/lastlog,

It is only incompatible with old static ia64 programs which access
utmp/wtmp/lastlog and the old utmp/wtmp/lastlog files.

> whether through accessor functions or poking at the files directly.

I don't think we ever encourage or even support accesing those files
directly.

> Given how slowly IA-32 programs run on IA-64, I think it is certainly

This can change in the future.

> not worth breaking compatibility for the native programs to gain
> compatibility with the emulated ones.
> If we can get rid of all the programs poking directly, then we certainly
> can through symbol version do anything with struct utmp (and translate the
> structures from one format to the other).

I will provide such functions.

> But best would be of course to use 64-bit format on disk and translate it
> to 32-bit programs.

It doesn't solve the problem for ia32 binaries. We have changed the
utmp/wtmp/lastlog format on ia32 once before. I don't see why we
can't do it for ia64. Ignore the old utmp/wtmp/lastlog for the time
being, x86-64 has the same problem. How is it solved on x86-64?

> 
> I think it is even questionable whether to define __WORDSIZE 32 in IA-64
> headers if __ia64__ is not defined. IA-64 does not use */lib64 and its
> compiler is not bi-architecture either. To build IA-32 binaries on IA-64
> box you have to pass -L/usr/i386-something-linux/lib or where the libraries
> live to the cross-compiler anyway, at which point I don't see why
> passing -I/usr/i386-something-linux/include cannot be done too
> (well, the cross-compiler can be even configured so that it does that
> itself).

It is for ia64 libc.so so that ia32 binaries will work correctly on
ia64.



H.J.


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