title: get attribute value by its name
body: <p>In my c++ code and in using xerces for sax parsing , i want to have attribute's value
  by it's name .
  how can i do that ?
  there is some thing like this in xerces document , but doesn't work :</p>
  
  <pre><code>String identifier = atts.getValue("id"); 
  </code></pre>
  
  <p>thanks in advance </p>