<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE vxml PUBLIC "-//W3C//DTD VOICEXML 2.1//EN" "http://www.w3.org/TR/voicexml21/vxml.dtd">
<vxml xml:lang="de-DE" version="2.1">
 <var name="audio_var" />
  <script>
    <![CDATA[
       function init()
        {
           audio_var='<audio src="$(SWISBSDK)/sounds/asrerror.wav" >';
         }
    ]]>
  </script>
  <form>
    <block>
      <value expr="init()"/>
      <prompt>
        <value expr="audio_var" />
        <audio src="$(SWISBSDK)/sounds/standard/closed_extro_1_bm.wav">Die Datei fehlt!</audio>        
      </prompt>
    </block>
  </form>
</vxml>

<audio src="$(SWISBSDK)/sounds/asrerror.wav" ><audio src="$(SWISBSDK)/sounds/standard/closed_extro_1_bm.wav" fetchtimeout="7s" fetchhint="prefetch">Alternativtext TTS, wenn die Datei fehlt!</audio>

bool isValidXML(const std::string & xmlstring)
{
    bool isValid = true;
    
    // ??
    
    return isValid;
}