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From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.questions
Subject: Re: Termcap/terminfo magic cookies (sg#, xmc#)
Message-ID: <9311@mimsy.UUCP>
Date: Wed, 11-Nov-87 20:28:26 EST
Article-I.D.: mimsy.9311
Posted: Wed Nov 11 20:28:26 1987
Date-Received: Sat, 14-Nov-87 06:02:00 EST
References: <846@quacky.UUCP> <5185@ncoast.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 29

In article <5185@ncoast.UUCP> allbery@ncoast.UUCP (Brandon Allbery) writes:
>I believe the idea is that a zero-width magic cookie is still a magic cookie.

Yes and no.

>Why?  Well, the purpose of the "magic cookie" is to inform the video hardware
>that all characters output from the screen position of the cookie to the next
>magic cookie or to the end of the screen.On the other hand, NO magic cookie
>means that an sg/smso will simply set a flag somewhere such that subsequent
>characters recieved from the terminal's input stream will come out in the
>specified attribute, _regardless_of_screen_position_.

This may be true of terminfo.  It is not true of termcap.  This
relates back to my gripe about :xn:.  `sg#', in combination with
`:xs:', provides exactly enough information about a terminal so
that `vi' and `more' can work.  It does not provide enough information
to deduce just what is really going on inside the terminal.  vi
and more only ever highlight entire lines, and this is all termcap
properly describes.

>Of course, my understanding was that this was SUPPOSED to be flagged in
>termcap with the boolean "ms" attribute (terminfo: "msgr")....

No, `ms' means only what it says: the terminal can move the cursor
while in standout mode without leaving standout mode.  vi does not
need to know how standout works, so termcap does not say.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris