Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!newstop!exodus!appserv!angel.Eng.Sun.COM!henry
From: henry@angel.Eng.Sun.COM (Henry McGilton)
Newsgroups: comp.text
Subject: Re: troff: what is |0 for?
Summary: Absolute Positioning
Message-ID: <477@appserv.Eng.Sun.COM>
Date: 1 Mar 91 23:18:30 GMT
References: <3989@uakari.primate.wisc.edu>
Sender: news@appserv.Eng.Sun.COM
Lines: 26

In article <3989@uakari.primate.wisc.edu>,
bin@primate.wisc.edu (Brain in Neutral) writes:

    *  The troff manual says, "a macro to underscore a string can be written

            *  .ds us
            *  \\$1\l'|0\(ul'
            *  ..

    *  OK, fine.  But what is the |0 in this magic sequence?  I don't
    *  find it described anywhere...

In the beginning of the troff manual,  in the section entitled
`Numerical parameter input', you will find a paragraph that reads like:

    The absolute position indicator | may be prepended to a number N
    to generate the distance to the vertical or horizontal place N.
    For vertically-oriented requests and functions, |N becomes the
    distance in basic units from the current vertical place on the
    page or in a diversion (section 7.4) to the the vertical place
    N.  For all other requests and functions, |N becomes the distance
    from the current horizontal place on the input line to the
    horizontal place N

Hope this helps,
		........  Henry