prefix (Nokogiri::XML::Reader)

    /*
     * call-seq:
     *   prefix
     *
     * Get the shorthand reference to the namespace associated with the node.
     */
    static VALUE prefix(VALUE self)
    {
      xmlTextReaderPtr reader;
      Data_Get_Struct(self, xmlTextReader, reader);
      const char * prefix = (const char *)xmlTextReaderConstPrefix(reader);
      if(prefix == NULL) return Qnil;

      VALUE MAYBE_UNUSED(enc) = rb_iv_get(self, "@encoding");
      return NOKOGIRI_STR_NEW2(prefix,
          RTEST(enc) ? StringValuePtr(enc) : NULL);
    }