title: CAPL how to define envVar in the FDX description file XML
body: <p>I'm trying to control Canoe config using FDX protocole, I can until now control start/stop measurement, frames, signals and sysvar request , but the problem is that i want to change envVar values , which not defined in the VECTOR FDX description file exemple (.xml).
  I know that for a signal :</p>
  <pre><code> &lt; identifier&gt;SigEngineSpeed&lt; /identifier&gt;
  
   &lt; signal value=&quot;raw&quot; name=&quot;EngineSpeed&quot;/ &gt; 
  </code></pre>
  <p>and for a sysvar :</p>
  
  <pre><code>   &lt;identifier&gt;VarHazardLightsSwitch&lt;/identifier&gt;
  
     &lt;sysvar name=&quot;HazardLightsSwitch&quot; namespace=&quot;FDX&quot;/&gt;
  </code></pre>
   
  <p>So could you help me please with the structure to define an envVar in the FDX description file.</p>