xpression as compiled to the buffer</p>
<div class="variablelist"><table border="0"><col align="left"/><tbody><tr><td><span class="term"><i><tt>buf</tt></i>:</span></td><td>a buffer to receive the output</td></tr><tr><td><span class="term"><i><tt>expr</tt></i>:</span></td><td>the compiled expression</td></tr></tbody></table></div></div>
        <hr/>
        <div class="refsect2" lang="en"><h3><a name="xmlExpExpDerive"/>xmlExpExpDerive ()</h3><pre class="programlisting"><a href="libxml2-xmlregexp.html#xm