title: What does IAlertNotifyHandler's OnNotification() return value do?
body: <p>BY now I've created a number of custom alert handlers for SharePoint 2007 using the <a href="http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.ialertnotifyhandler.aspx" rel="nofollow noreferrer">IAlertNotifyHandler</a> interface. Using this interface you have to implement a method called <a href="http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.ialertnotifyhandler.onnotification.aspx" rel="nofollow noreferrer">OnNotification()</a>, which has the following signature:</p>
  
  <pre><code>bool OnNotification (SPAlertHandlerParams ahp);
  </code></pre>
  
  <p>As you can see this method should return a boolean value. The official MSDN docs list the following explanation of this return value:</p>
  
  <blockquote>
    <p><strong>true</strong> if Windows SharePoint Services
    marks the notification as processed;
    otherwise <strong>false</strong></p>
  </blockquote>
  
  <p>At first I thought this meant that if you return <em>true</em> you signal SharePoint that your handler has done all alert processing and SharePoint shouldn't execute its default behaviour. However, in practice there doesn't seem to be any difference in the way the alerts are handled. You can return <em>true</em> or <em>false</em>, it doesn't make any difference.</p>
  
  <p>I then used Reflector to dissassemble the source code, but unfortunately the code that processes OnNotification's return value isn't managed, but native.</p>
  
  <p>So who knows what that return value means?</p>