title: Identify stylus barrel button (win32)
body: <p>I am creating an application that uses the tablet API for windows and so far I was able to capture the input of the stylus succesfully. I am able to handle the movement, stylus down and up events and pressure. What I am still missing is the ability to identify the barrel button pressed. While I am capturing the <code>StylusButtonDown</code> event, this is fired also when the stylus is down on the tablet.</p>
  <p>For reference here is my (ideal) implementation:</p>
  <pre class="lang-cpp prettyprint-override"><code>STDMETHOD(StylusButtonDown)(IRealTimeStylus* rts, STYLUS_ID id, const GUID* guid, POINT* pt)
  {
    if (BARREL_BUTTON_ID == *guid) {
      s_buttonDown = true;
  
      // DEBUG
      std::cout &lt;&lt; &quot;[StylusButtonDown]&quot; &lt;&lt; std::endl;
      // DEBUG
    }
    return S_OK;
  }
  </code></pre>
  <p>The problem I have is to fill in the <code>BARREL_BUTTON_ID</code> constant. Any expert with an idea?
  Thanks a lot!</p>