[Qt-qml] Q_INVOKABLE member function: Valid argument types

[Johan Paul]

Hi Jonathan,

Q_INVOKABLEs are implements as slots in the C++ class, which means they 
are just method calls in the end. AFAIK you should be allowed to give a 
pointer to an integer if you so wish to a slot. Sounds like the runtime 
error (segfault?) comes from something else.

You cannot return values from Q_INVOKABLES as they are Qt slots which 
cannot return values.


Cheers,

Johan


> Hi,
>
> What are the valid argument types of an invokable member function of a
> QML extension C++ class? I have noticed that these work:
>
> Q_INVOKABLE void myFunc1(int myInputInt);
> Q_INVOKABLE void myFunc2(int&  myInputInt);    // but myInputInt cannot
> be modified.
>
> while this does not work:
>
> Q_INVOKABLE void myFunc3(int * myOutputInt);    // This will cause a
> runtime error when running qmlviewer.
>
> It appears that:
> 1. The argument can be an object of (or reference to) a basic C/C++ data
> type (int, int&, double, double&, ...).
> 2. The argument can be an object or (or reference to) a Qt class which
> relates to a basic QML type (QString, QString&, QVariant, QVariant&, ...).
> 3. The argument can be a pointer to QObject or its derived classes
> (QObject *, QWidget *, ...).
> ...
>
> Is there a Qt documentation page on this subject?
>
> Perhaps this is a related question: What are the valid return types of
> an invokable member function?
>
>
> Thanks,
>
> Jonathan
>
>
>
>
>
>
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