<refentry id="man.charmap.use.subset">
<refmeta>
<refentrytitle>man.charmap.use.subset</refentrytitle>
<refmiscinfo role="type">boolean</refmiscinfo>
</refmeta>
<refnamediv>
<refname>man.charmap.use.subset</refname>
<refpurpose>Use subset of character map instead of full map?</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment id='man.charmap.use.subset.frag'>
<xsl:param name="man.charmap.use.subset" select="1"/>
</src:fragment>
</refsynopsisdiv>

<refsect1><title>Description</title>

<para>If the value of the
<parameter>man.charmap.use.subset</parameter> parameter is non-zero,
a subset of the roff character map is used instead of the full roff
character map. The profile of the subset used is specified by the
<parameter>man.charmap.subset.profile</parameter> parameter.</para>

<note>
  <para>You may want to experiment with setting a non-zero value of
  <parameter>man.charmap.use.subset</parameter>, so that the full
  character map is used. Depending on which XSLT engine you run,
  setting a non-zero value for
  <parameter>man.charmap.use.subset</parameter> may significantly
  increase the time needed to process your documents. Or it may
  not. For example, if you set it and run it with xsltproc, it seems
  to dramatically increase processing time; on the other hand, if you
  set it and run it with Saxon, it does not seem to increase
  processing time nearly as much.</para>

  <para>If processing time is not a important concern and/or you can
  tolerate the increase in processing time imposed by using the full
  character map, set <parameter>man.charmap.use.subset</parameter> to
  zero.</para>
</note>

<refsect2>
<title>Details</title>
<para>For converting certain Unicode symbols and special characters in
UTF-8 or UTF-16 encoded XML source to appropriate groff/roff
equivalents in man-page output, the DocBook XSL Stylesheets
distribution includes a <ulink
url="http://docbook.sourceforge.net/snapshot/xsl/manpages/charmap.groff.xsl"
>roff character map</ulink> that is compliant with the <ulink
url="http://www.w3.org/TR/xslt20/#character-maps" >XSLT character
map</ulink> format as detailed in the XSLT 2.0 specification. The map
contains more than 800 character mappings and can be considered the
standard roff character map for the distribution.</para>

<note>
<para>You can use the <parameter>man.charmap.uri</parameter>
parameter to specify a URI for the location for an alternate roff
character map to use in place of the standard roff character map
provided in the distribution.</para>
</note>

<para>Because it is not terrifically efficient to use the standard
800-character character map in full -- and for most (or all) users,
never necessary to use it in full -- the DocBook XSL Stylesheets
support a mechanism for using, within any given character map, a
subset of character mappings instead of the full set. You can use the
<parameter>man.charmap.subset.profile</parameter> parameter to tune
the profile of that subset to use.</para>

</refsect2>
</refsect1>
</refentry>
