#include <QtNetwork/qabstractsocket.h> #ifndef QABSTRACTSOCKET_H class QAbstractSocket: public QIODevice{ /* Some contents are skipped to improve readability */ public: enum NetworkLayerProtocol{ IPv4Protocol = 0, IPv6Protocol = 1, UnknownNetworkLayerProtocol = -1, }; /* ... */ }; #endif // QABSTRACTSOCKET_H