[vtk-developers] Implicit copy constructors in VTK

[Robert Maynard]

I have updated the coding standards with what I think are clear
guidelines for implementing non vtkObject derived classes.

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
>>