<refentry id="optional.element">
<?dbhtml filename="optional.html"?>
<refentryinfo>
<pubdate>$Date$</pubdate>
<releaseinfo>$Revision$</releaseinfo>
</refentryinfo>

<refmeta>
<indexterm><primary>elements</primary>
<secondary>optional</secondary></indexterm>
<refentrytitle>optional</refentrytitle>
<refmiscinfo>Element</refmiscinfo>
</refmeta>
<refnamediv>
<refname>optional</refname>
<refpurpose>&optional.purpose;</refpurpose>
</refnamediv>

&optional.synopsis.gen;
<refsect1 condition='ref.description'><title>Description</title>

<para>
The <sgmltag>Optional</sgmltag> element indicates that a specified argument,
option, or other text is optional. The precise meaning of
<quote>optional</quote> varies according to the application or process
begin documented.
</para>

<refsect2 id="dbreproc.optional"><title>Processing expectations</title>
<para>
&format.inline;
</para>
<para>
Optional arguments in a <sgmltag>Synopsis</sgmltag> are usually given special
typographic treatment, often they are surrounded by square brackets. The
<sgmltag>Optional</sgmltag> tag is expected to <emphasis>generate</emphasis> the brackets.
</para>
<para>
Outside a <sgmltag>Synopsis</sgmltag>, the typographic treatment of
<sgmltag>Optional</sgmltag> is application-specific.
</para>
</refsect2> 

<refsect2 role='fu' revision="4.0"><title>&FutureChanges;</title>
<para>
<!--do not index this occurance-->
&fu.interfacedefinition;
</para>
</refsect2>


&optional.parents.gen;
&optional.children.gen;
</refsect1>
<refsect1 condition='ref.elem.seealso'><title>See Also</title>
&optional.seealso.gen;
</refsect1>
<refsect1><title>Examples</title>

<para>
The &UNIX; <command>ls</command> command could be documented as follows:
</para>

<informalexample role="example-source">
<programlisting>&optional.example.1.txt;</programlisting>
</informalexample>

<anchor id="ex.os.optional.1" role="HACK-ex.out.start"/>
&optional.example.1.gen;
<anchor id="ex.oe.optional.1" role="HACK-ex.out.end"/>

<para>
which might generate the following output:
<screen>
ls [ -abcCdfFgilLmnopqrRstux1 ] 
   [names]
</screen>
</para>

&optional.example.seealso.gen;
</refsect1>
</refentry>

