I have a project where I need to use functions defined from xpath 1.0 like count and strings. Here is the definition of count:

Function: number count(node-set)

The count function returns the number of nodes in the argument node-set.

when running with xmllint e.g. I can enter on this playlist.xml (http://grantm.github.io/perl-libxml-by-example/_static/xpath-sandbox/xpath-sandbox.html)

xmllint --xpath "count(//person)" playlist.xml

and I get the number 18 as a result.

When using libxml++ I get the error message from nodes/node.cc:88 Only nodeset result types are supported.

  auto result = xmlXPathEval((const xmlChar*)xpath.c_str(), ctxt);
  if (!result)
  {
    xmlXPathFreeContext(ctxt);
    throw xmlpp::exception("Invalid XPath: " + xpath);
  }

  if (result->type != XPATH_NODESET)
  {
    xmlXPathFreeObject(result);
    xmlXPathFreeContext(ctxt);
    throw xmlpp::internal_error("Only nodeset result types are supported.");

Is there a way to use functions that have a result type that is not an xpath nodeset?