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Re: strxfrm output stability
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 9 Sep 2015 13:52:35 +0000
- Subject: Re: strxfrm output stability
- Authentication-results: sourceware.org; auth=none
- References: <55EF4F95 dot 4020703 at redhat dot com> <alpine dot DEB dot 2 dot 10 dot 1509082115520 dot 24360 at digraph dot polyomino dot org dot uk> <55F01C68 dot 1020807 at redhat dot com>
On Wed, 9 Sep 2015, Florian Weimer wrote:
> On 09/08/2015 11:33 PM, Joseph Myers wrote:
> > On Tue, 8 Sep 2015, Florian Weimer wrote:
> >
> >> Why is it acceptable to change the strxfrm output between glibc
> >> releases, as implied by several bug reports (e.g. bug 18927)? Doesn't
> >> this break backwards compatibility in a major way?
> >
> > I think strxfrm output is much like the layout of lots of internal types -
> > it's valid within a process (as long as LC_COLLATE is the same at both
> > calls), but not necessarily stable over time (type sizes, alignment,
> > offsets of public fields etc. need to be stable, but the internal layout
> > of an opaque type need not be). It's inevitable that fixing incorrect
> > collation, updating collation for new national and international standards
> > and for new Unicode characters, etc. will involve changing the output.
>
> Okay, fair enough. Can we put this into the documentation?
I think it would be reasonable to include this information in the
documentation of collation (as well as referring to the issue in
documentation for distributors).
--
Joseph S. Myers
joseph@codesourcery.com