[vtk-developers] Implicit copy constructors in VTK

[Bill Lorensen]

I agree with Robert. I'd rather see the explicit lions rather than a macro.
Makes code easier to follow for novices.



On Wed, Jul 24, 2013 at 12:33 PM, Robert Maynard <robert.maynard at kitware.com
> wrote:

> Personally I don't see enough complaints about people forgetting to
> follow the rule of three to add another macro helper to VTK.
> We have a smoke test that does verify that all classes that derive
> from vtkObject have private copy constructor and copy assignment
> operator.
>
>
> On Wed, Jul 24, 2013 at 11:55 AM, Jean-Christophe Fillion-Robin
> <jchris.fillionr at kitware.com> wrote:
> > Would it make sense to provide a VTK_DISABLE_COPY() macro ?  (Similar to
> > what is done within Qt with Q_DISABLE_COPY [1])
> >
> > [1] http://qt-project.org/doc/qt-5.0/qtcore/qobject.html#Q_DISABLE_COPY
> >
> >
> > On Wed, Jul 24, 2013 at 11:48 AM, Marcus D. Hanwell
> > <marcus.hanwell at kitware.com> wrote:
> >>
> >> I agree with Rob, and can take care of putting a patch together for
> >> the classes you call out. The rules outlined only make sense for
> >> vtkObject derived classes, we should provide clear guidelines for
> >> those that are not part of that hierarchy too.
> >>
> >> On Wed, Jul 24, 2013 at 11:06 AM, Robert Maynard
> >> <robert.maynard at kitware.com> wrote:
> >> > The VTK coding standards should be amended to state that those rules
> >> > are only valid for classes that derive from vtkObject.
> >> >
> >> > Classes like vtkBond, vtkTuple, vtkBoundingBox all which don't inherit
> >> > from vtkObject should follow the rule of three and implement the copy
> >> > and assignment constructor if they implement a destructor.
> >> >
> >> > On Wed, Jul 24, 2013 at 10:50 AM, Sean McBride <
> sean at rogue-research.com>
> >> > wrote:
> >> >> Hi all,
> >> >>
> >> >> So I'm looking at the clang warnings on Rogue7, but need C++ help
> >> >> before I can proceed further.  We have two similar warnings,
> repeated for
> >> >> several classes:
> >> >>
> >> >> VTK/Common/DataModel/vtkBond.h:30:3: warning: definition of implicit
> >> >> copy constructor for 'vtkBond' is deprecated because it has a
> user-declared
> >> >> destructor [-Wdeprecated]
> >> >>   ~vtkBond();
> >> >>   ^
> >> >>
> >> >> VTK/Common/Math/vtkQuaternion.h:201:8: warning: definition of
> implicit
> >> >> copy constructor for 'vtkQuaternion<float>' is deprecated because it
> has a
> >> >> user-declared copy assignment operator [-Wdeprecated]
> >> >>   void operator=(const vtkQuaternion<T>& q);
> >> >>        ^
> >> >>
> >> >> From what I can tell, in C++11, the implicit generation of copy
> >> >> constructors is now deprecated if 1) you provide a user-declared
> destructor
> >> >> or 2) you provide a user-declared copy assignment operator.
> >> >> <http://stackoverflow.com/a/11255258>
> >> >>
> >> >> So it would seem a solution is to provide an explicit copy
> constructor,
> >> >> but VTK's coding standards gives me pause: "Classes should have
> protected
> >> >> constructors and destructors, and privately declared but
> unimplemented copy
> >> >> constructor and assignment operator. Rationale: VTK’s reference
> counting
> >> >> implementation depends on carefully controlling each object’s
> reference
> >> >> count".
> >> >>
> >> >> So now I'm not sure how to proceed...
> >> >>
> >> >> Thanks,
> >> >>
> >> >> --
> >> >> ____________________________________________________________
> >> >> Sean McBride, B. Eng                 sean at rogue-research.com
> >> >> Rogue Research                        www.rogue-research.com
> >> >> Mac Software Developer              Montréal, Québec, Canada
> >> >> _______________________________________________
> >> >> Powered by www.kitware.com
> >> >>
> >> >> Visit other Kitware open-source projects at
> >> >> http://www.kitware.com/opensource/opensource.html
> >> >>
> >> >> Follow this link to subscribe/unsubscribe:
> >> >> http://www.vtk.org/mailman/listinfo/vtk-developers
> >> >>
> >> > _______________________________________________
> >> > Powered by www.kitware.com
> >> >
> >> > Visit other Kitware open-source projects at
> >> > http://www.kitware.com/opensource/opensource.html
> >> >
> >> > Follow this link to subscribe/unsubscribe:
> >> > http://www.vtk.org/mailman/listinfo/vtk-developers
> >> >
> >> _______________________________________________
> >> Powered by www.kitware.com
> >>
> >> Visit other Kitware open-source projects at
> >> http://www.kitware.com/opensource/opensource.html
> >>
> >> Follow this link to subscribe/unsubscribe:
> >> http://www.vtk.org/mailman/listinfo/vtk-developers
> >>
> >
> >
> >
> > --
> > +1 919 869 8849
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtk-developers
>
>


-- 
Unpaid intern in BillsBasement at noware dot com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20130724/afd137b2/attachment.html>