optional
optional — Optional information.
Synopsis
- Zero or more of:
- text
replaceable
- Graphic inlines
- Indexing inlines
- Linking inlines
- Ubiquitous inlines
abbrev
acronym
alt
anchor
annotation
biblioref
coref
date
emphasis
(db._emphasis)firstterm
(db._firstterm)footnote
footnoteref
foreignphrase
(db._foreignphrase)glossterm
(db._glossterm)indexterm
(db.indexterm.endofrange)indexterm
(db.indexterm.singular)indexterm
(db.indexterm.startofrange)inlinemediaobject
link
olink
phrase
(db._phrase)quote
(db._quote)remark
subscript
superscript
trademark
wordasword
xref
Attributes
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.
This element occurs in 53 elements.
This element contains 29 elements.
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>
ls -abcCdfFgilLmnopqrRstux1
names