....
GUIEventHandler: In copy constructor 'osgGA::GUIEventHandler::GUIEventHandler(const osgGA::GUIEventHandler&, const osg::CopyOp&)':
/include/osgGA/GUIEventHandler:56:9: error: base class 'class osg::Object' should be explicitly initialized in the copy constructor [-Werror=extra]
It seems the diamond problem:
A = osg::Object
/ \
/ \--> Virtual inheritance
B C
\ /
\ /
D = EventHandler
|
|
E = GUIEventHandler
The most derived class(E) handles the instantiation of A (osg::Object), but all have to be responsible in case they are the ones instantiated.
In case A is not initialized in the copy constructor of derived classes the default constructor will be called, which seems a bug.
I've added osg::Object to the initalization list of EventHandler and GUIEventHandler copy constructors, because both classes are instantiables.
"