title: QT program crashes after connect()
body: <p>I'm trying to write my new app, but it crashes every time I press a button on QDialog.</p>
  
  <p>Here's my code :</p>
  
  <p>mainwindow.h</p>
  
  <pre><code>#include &lt;QMainWindow&gt;
  #include "creatlist.h"
  
  namespace Ui {
  class MainWindow;
  
  }
  
  class MainWindow : public QMainWindow
  {
      Q_OBJECT
  
  public:
      explicit MainWindow(QWidget *parent = 0);
      ~MainWindow();
      QDialog* creatList;
  
  public slots:
      void tableFull(){
        ...some code here...
       }
  
  private:
      Ui::MainWindow *ui;
  };
  </code></pre>
  
  <p>creatlist.h :</p>
  
  <pre><code>#include &lt;QDialog&gt;
  #include "mainwindow.h"
  
  namespace Ui {
  class creatlist;
  }
  
  class MainWindow;
  
  class creatlist : public QDialog
  {
      Q_OBJECT
  
  public:
      explicit creatlist(QWidget *parent = 0);
      ~creatlist();
      MainWindow* mainwindow;
  signals:
      void updateList();
  
  public slots:
      void ready(){
         ///////////////////////////////////////////////////////////crash
       connect(this,SIGNAL(updateList()),mainwindow,SLOT(tableFull()));
       emit updateList();
  
     }
  
  private:
      Ui::creatlist *ui;
  };
  </code></pre>
  
  <p>If i try to send some signals my app crashes with a Segmentation Fault.</p>
  
  <p>I did:</p>
  
  <pre><code>void creatlist::ready()
  {
  mainwindow = new MainWindow(this);
  emit mainwindow-&gt;linktableFull();
  }
  </code></pre>
  
  <p>but if I try to do <code>QTextBroser.append("hue hue");</code> in linktableFull(), QTextBrowser is always empty.</p>