title: Qt Signal Slot: Signal is sent but Slot is not called
body: <p>I'm using Qt in Visual Studio 2013 in C++. I'm trying to connect a signal to a slot. The problem is that the signal is sent but the slot function is never called and I don't know what happened. This code was working earlier but after I migrated the code from Visual Studio 2012 in 32 bit to Visual Studio 2013 in 64 bit and made some changes, it doesn't work anymore. It prints the debug statements: before sending, image sent, and connected but it doesn't print out image received. Can someone please help?</p>
  
  <p>Streamer.h</p>
  
  <pre><code>signals:
      //Signal to output frame to be displayed
      void processedImageStream(const vector&lt;QImage&gt; &amp;imgs, const QImage &amp;image2, const QImage &amp;image3, const QImage &amp;image4);
  </code></pre>
  
  <p>Streamer.cpp in the run() function</p>
  
  <pre><code>qDebug() &lt;&lt; "before sending";
  emit processedImageStream(imgs,imgIntel, imgIntelDepth, imgIntelIR);
  qDebug() &lt;&lt; "images sent!";
  </code></pre>
  
  <p>MainWindow.h</p>
  
  <pre><code>private slots:
      //Display video frame in streamer UI
      void updateStreamerUI(const vector&lt;QImage&gt; &amp;imgs, const QImage &amp;imgIntel, const QImage &amp;imgIntelDepth, const QImage &amp;imgIntelIR);
  private:
      Streamer* myStreamer;
  </code></pre>
  
  <p>MainWindow.cpp</p>
  
  <pre><code>MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
  {
      //Streamer initialization
      myStreamer = new Streamer();
      QObject::connect(myStreamer, SIGNAL(processedImageStream(vector&lt;QImage&gt;, QImage, QImage, QImage)), this, SLOT(updateStreamerUI(vector&lt;QImage&gt;, QImage, QImage, QImage)));
      qDebug() &lt;&lt; "connected";
      ui.setupUi(this);
  }
  
  //slot for when new images are sent from the Streamer class
  void MainWindow::updateStreamerUI(const vector&lt;QImage&gt; &amp;imgs, const QImage &amp;imgIntel, const QImage &amp;imgIntelDepth, const QImage &amp;imgIntelIR) {
      qDebug() &lt;&lt; "images received!";
      //rest of the code
  }
  </code></pre>