The new function cPlugin::MainThreadHook() can be used by plugins to perform actions in the context of the main program thread

PLUGINS.html

@@ -63,6 +63,7 @@ structures and allows it to hook itself into specific areas to perform special a
 <li><a href="#User interaction">User interaction</a>
 <li><a href="#Housekeeping">Housekeeping</a>
 <!--X1.3.47--><table width=100%><tr><td bgcolor=#FF0000>&nbsp;</td><td width=100%>
+<li><a href="#Main thread hook">Main thread hook</a>
 <li><a href="#Activity">Activity</a>
 <!--X1.3.47--></td></tr></table>
 <li><a href="#Setup parameters">Setup parameters</a>
@@ -620,6 +621,27 @@ the plugin should launch a separate thread to do this.
 </b>
 
 <!--X1.3.47--><table width=100%><tr><td bgcolor=#FF0000>&nbsp;</td><td width=100%>
+<a name="Main thread hook"><hr><h2>Main thread hook</h2>
+
+<center><i><b>Pushing in...</b></i></center><p>
+
+Normally a plugin only reacts on user input if directly called through its
+<a href="#Main menu entry">main menu entry</a>, or performs some background
+activity in a separate thread. However, sometimes a plugin may need to do
+something in the context of the main program thread, without being explicitly
+called up by the user. In such a case it can implement the function
+
+<p><table><tr><td bgcolor=#F0F0F0><pre>
+virtual void MainThreadHook(void);
+</pre></td></tr></table><p>
+
+in which it can do this. This function is called for every plugin once during
+every cycle of VDR's main program loop, which typically happens once every
+second.
+<b>Be very careful when using this function, and make sure you return from it
+as soon as possible! If you spend too much time in this function, the user
+interface performance will become sluggish!</b>
+
 <a name="Activity"><hr><h2>Activity</h2>
 
 <center><i><b>Now is not a good time!</b></i></center><p>