check.id.unique
check.id.unique — Warn users about references to non-unique IDs
Synopsis
<xsl:template name="check.id.unique">
<xsl:param name="linkend"/>
...
</xsl:template>
Description
If passed an ID in linkend,
check.id.unique prints
a warning message to the user if either the ID does not exist or
the ID is not unique.