May 2010
Intermediate to advanced
552 pages
13h 37m
English
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Name
optional — Optional information
Synopsis
optional ::=
(text | phrase db._phrase | replaceable
| Graphic inlines | Indexing inlines | Linking inlines | Ubiquitous inlines)*
Attribute synopsis
Description
The optional element indicates that a specified
argument, option, or other text is optional. The precise meaning of
“optional” varies according to the application or process
being documented.
Processing expectations
Formatted inline.
Optional arguments in a synopsis are usually
given special typographic treatment, and often they are surrounded by
square brackets. The optional tag is expected to
generate the brackets.
Outside a synopsis, the typographic treatment
of optional is application specific.
See Also
computeroutput, constant, literal, markup, option, parameter, prompt, replaceable, tag, userinput, varname
Examples
<article xmlns='http://docbook.org/ns/docbook'> <title>Example optional</title> <synopsis> ls <option>-abcCdfFgilLmnopqrRstux1</option> <optional>names</optional> </synopsis> </article>
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.