in a
<code>&lt;target&gt;</code> tag's <code>unless</code> attribute to
conditionally run that target. For example, running the following target:</p>
<pre>
&lt;target name=&quot;xmlBuild&quot; depends=&quot;chkXmlBuild&quot; unless=&quot;xmlBuild.notRequired&quot;&gt;
  ...
&lt;/target&gt;
</pre>
will first run the <code>chkXmlBuild</code> target, which contains
the <code>&lt;uptodate&gt;</code> task that determines whether
<code>xmlBuild.notRequired</code> gets set. The property named in
the <code>unless</