Where is Qt’s PointerToMemberFunction defined?

Question

In this question I was able to adapt the QObject method

QMetaObject::Connection
QObject::connect(const QObject * sender,
    const char * signal,
    const QObject * receiver,
    const char * method,
    Qt::ConnectionType type = Qt::AutoConnection)

into a variant that accepted a QSharedPointer instead of a QObject* as its first parameter:

template<class T> QMetaObject::Connection
connect_from_pointer(const QSharedPointer<T> &sender,
    const char *signal,
    const QObject *receiver,
    const char *method,
    Qt::ConnectionType type = Qt::AutoConnection)

I’d like to do the same thing with the version that takes function pointers,

QMetaObject::Connection
QObject::connect(const QObject * sender,
    PointerToMemberFunction signal,
    const QObject * receiver,
    PointerToMemberFunction method,
    Qt::ConnectionType type = Qt::AutoConnection)

but I can’t figure out what PointerToMemberFunction is or where it’s defined! What is this type?

Answer 1

It is just "sugar" for documentation, true definition you can find in qobject.h (Qt source code):

    static QMetaObject::Connection connect(const QObject *sender, const char *signal,
                        const QObject *receiver, const char *member, Qt::ConnectionType = Qt::AutoConnection);

    static QMetaObject::Connection connect(const QObject *sender, const QMetaMethod &signal,
                        const QObject *receiver, const QMetaMethod &method,
                        Qt::ConnectionType type = Qt::AutoConnection);

    inline QMetaObject::Connection connect(const QObject *sender, const char *signal,
                        const char *member, Qt::ConnectionType type = Qt::AutoConnection) const;

#ifdef Q_QDOC
    static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection);
    static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, Functor functor);
    static QMetaObject::Connection connect(const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection);
#else
    //Connect a signal to a pointer to qobject member function
    template <typename Func1, typename Func2>
    static inline QMetaObject::Connection connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal,
                                     const typename QtPrivate::FunctionPointer<Func2>::Object *receiver, Func2 slot,
                                     Qt::ConnectionType type = Qt::AutoConnection)
    {
        typedef QtPrivate::FunctionPointer<Func1> SignalType;
        typedef QtPrivate::FunctionPointer<Func2> SlotType;

        Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value,
                          "No Q_OBJECT in the class with the signal");

        //compilation error if the arguments does not match.
        Q_STATIC_ASSERT_X(int(SignalType::ArgumentCount) >= int(SlotType::ArgumentCount),
                          "The slot requires more arguments than the signal provides.");
        Q_STATIC_ASSERT_X((QtPrivate::CheckCompatibleArguments<typename SignalType::Arguments, typename SlotType::Arguments>::value),
                          "Signal and slot arguments are not compatible.");
        Q_STATIC_ASSERT_X((QtPrivate::AreArgumentsCompatible<typename SlotType::ReturnType, typename SignalType::ReturnType>::value),
                          "Return type of the slot is not compatible with the return type of the signal.");

        const int *types = 0;
        if (type == Qt::QueuedConnection || type == Qt::BlockingQueuedConnection)
            types = QtPrivate::ConnectionTypes<typename SignalType::Arguments>::types();

        return connectImpl(sender, reinterpret_cast<void **>(&signal),
                           receiver, reinterpret_cast<void **>(&slot),
                           new QtPrivate::QSlotObject<Func2, typename QtPrivate::List_Left<typename SignalType::Arguments, SlotType::ArgumentCount>::Value,
                                           typename SignalType::ReturnType>(slot),
                            type, types, &SignalType::Object::staticMetaObject);
    }