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POqt signals/slots in a plugin
 

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  1. POqt signals/slots in a plugin
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    <p>I have an app with such structure: all the datatypes (<code>class INode</code>) are stored in plugins (DLLs). Some of the datatypes can be drawn (if they're <code>IDrawable</code>). </p> <p>To load an object of, e.g. <code>class PointCloudNode: public INode</code> I have a special input plugin (DLL) which is called <code>class PointCloudParser: public IIOPlugin</code> and <code>IIOPlugin</code> is a thread with some specific functionality: <code>class IIOPlugin: public QThread</code>.</p> <p>All the objects are created by <code>NodeFactory</code> class which is a singleton stored in separate DLL.</p> <p>And here's the problem:</p> <pre><code>void PointCloudNode::update() { QObject::connect (this,SIGNAL(tmptmp()),this,SLOT(drawObject())); emit tmptmp(); } </code></pre> <p>If I do this from any thread (main thread or the Input Plugin thread)</p> <pre><code>NodeFactory* fab = NodeFactory::getInstance(); boost::shared_ptr&lt;INode&gt; pc(fab-&gt;createNode("pointCloud","myPC")); boost::shared_ptr&lt;IDrawable&gt; dr = boost::dynamic_pointer_cast&lt;IDrawable&gt;(pc); dr-&gt;update(); </code></pre> <p>The update launches, the <code>tmptmp()</code> signal is emitted, and the slot (<code>drawObject()</code>) executes correctly.</p> <p><b>BUT</b> if do just the same, but create the object in my Input Plugin, pass over the shared pointer and execute <code>dr->update()</code> in another function, the slot <code>drawObject()</code> is never entered though all the code is executed (including <code>connect</code>, etc.).</p> <p>To be more precise, here's the Input Plugin:</p> <pre><code> void PointCloudParserPlugin::doLoad(const QString&amp; inputName, boost::shared_ptr&lt;INode&gt; container) { NodeFactory* factory = NodeFactory::getInstance(); boost::shared_ptr&lt;INode&gt; node = factory-&gt;createNode("pointCloud", inputName); // here goes the loading itself, nothing special... container-&gt;addChild(node); //that's the container where I keep all the objects //boost::dynamic_pointer_cast&lt;IDrawable&gt;(container-&gt;getChild(inputName))-&gt;update(); //If I uncomment this line, it all works: the slot is launched. emit loadingFinished(inputName); // it executes the following function } </code></pre> <p>The last emit is connected to this:</p> <pre><code> void GeomBox::updateVisualization(const QString&amp; fileName) { boost::shared_ptr&lt;INode&gt; node = container_-&gt;getChild(fileName); boost::shared_ptr&lt;IDrawable&gt; nodeDrawable = boost::dynamic_pointer_cast&lt;IDrawable&gt;(node); nodeDrawable-&gt;update(); //this is the problem line: update() executes, connect() works, but the slot never runs :( } </code></pre> <p>How come? The <code>node</code> object is the same all the way through, it is valid. Every line in code in launched, <code>QObject::connect</code> doesn't write anything to debug window, the signal <code>tmptmp()</code> is emitted, but the slot <code>drawObject()</code> in one case is never reached? Any ideas?</p> <p><b>Upd.:</b> If I do not inherit <code>IIOPlugin</code> from <code>QThread</code>, everything works fine (i.e. load the object in the main thread). I expected the signals/slots to work across the threads...</p>
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    1. USMikhail
    1. USMikhail
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      1. VTUpMod
    1. COhave you done, qmake, make clean, make all again?
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      1. USRonny Brendel
    2. CO* have you included this last line in the source for plugins? ( Q_EXPORT_PLUGIN2(xxx,XXX))
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      1. USRonny Brendel
    3. COyep, I've done all of that it seems something's wrong with signal/slots between DLLs..
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      1. USMikhail
 

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