#include <QtNetwork/qabstractsocket.h>
#ifndef QABSTRACTSOCKET_H
class QAbstractSocket: public QIODevice{
   /* Some contents are skipped to improve readability */
   public: enum SocketError{
      /* ... */
      AddressInUseError = 8,
      /* ... */
   };
   /* ... */
};
#endif // QABSTRACTSOCKET_H