How does the Xref: field in news articles work?

[lwall at sdcrdcf.UUCP]

In article <sdccsu3.2218> taylor at sdccsu3.UUCP (Dave Taylor) writes:
>
>	I have noticed that articles that are cross-posted (ie posted
>to more than one group) have a line of the form;
>
>Xref: 4454 343 898
>
>at the top.
>
>	How does one interpret this?  Is it as it seems, they apply to
>the specified groups IN ORDER as presented in the 'Newsgroup:' line?

This is correct.  You have a system with rn, which makes use of the Xref
line to mark articles as read in other newsgroups.  The Xref line is not
put in by standard inews--there is a patch that comes with the rn installation
kit.  Rn is still in beta test, so most of the people on the net won't have
the foggiest idea what you're talking about.

To quell a few worries before they start: the Xref line is local only, and is
not sent out to other systems.  It is the only modification to standard news
that rn strongly desires.  Rn will in fact run without it, but you'd see
duplicate articles.

Larry Wall
{allegra,burdvax,cbosgd,hplabs,ihnp4,sdcsvax}!sdcrdcf!lwall