title: What does the following function do?
body: <p>I am looking for Qt's implemention of the function <code>QObject::qt_metacall(_c, _id, _a);</code> this is where a given function name is converted into index. But I am not able to find the function implementation anywhere in their source code.</p>
  
  <pre><code>int ssObject::qt_metacall(QMetaObject::Call _c, int _id, void **_a)
  {
      _id = QObject::qt_metacall(_c, _id, _a);
      if (_id &lt; 0)
          return _id;
      if (_c == QMetaObject::InvokeMetaMethod) {
          switch (_id) {
          case 0: readyToPrint(); break;
          case 1: readyToPrint1((*reinterpret_cast&lt; int(*)&gt;(_a[1]))); break;
                 //''''
  
           }
      return _id;
     }
  </code></pre>
  
  <p><strong>Why is parent class's <code>qt_metacall</code> is called ?</strong></p>