title: QMetaObject::connectSlotsByName: No matching signal
body: <p>I set a QT menu, which is automatically connected with action function <code>on_actionOpen_triggered()</code>. Later I want to pass a filename string to this function in order to call this function manually in a special condition. So I changed the function signature to <code>on_actionOpen_triggered( const char *filename_in )</code>. After this change the program is running well, but there is a complain in terminal, </p>
  
  <blockquote>
    <p>QMetaObject::connectSlotsByName: No matching signal for on_actionOpen_triggered(const char*)</p>
  </blockquote>
  
  <p>I am wondering what happened, and how I can add arguments for this menu action functions.</p>
  
  <p>Thank you.</p>