[vtkusers] Unregister(QObjectBase *) vs Delete()

[Bill Lorensen]

There is really no difference.
Look at the source code for ::Delete and ::UnRegister in Common/vtkObjectBase.

The documentation for UnRegister says:
  // Description:
  // Decrease the reference count (release by another object). This
  // has the same effect as invoking Delete() (i.e., it reduces the
  // reference count by 1).
  virtual void UnRegister(vtkObjectBase* o);


On Wed, Jun 23, 2010 at 5:38 AM, Barth, Sebastian
<sebastian.barth at iosb.fraunhofer.de> wrote:
> Hello vtkusers,
>
> I tried to find out what is the difference between Unregister(QObjectBase *) and Delete() - Without success.
> Could you please explain?
>
> What I know about reference counting (please correct me):
>
> vtkPolyDataMapper * mapperA = vtkPolyDataMapper::New(); // Reference count of   mapperA = 1.
> vtkPolyDataMapper * mapperB = vtkPolyDataMapper::New(); // Reference count of   mapperB = 1.
>
> actor->SetMapper(mapperA);                                              // Reference count of   mapperA = 2 (or maybe more?)
> actor->SetMapper(mapperB);                                              // Reference count of   mapperA = 1,
>                                                                                //                              mapperB = 2 (or maybe more?)
>
> mapperA->Delete();                                                      // Reference count of   mapper A - 1 = 0 -> deleted
>
> Is this code above a correct way or is it illegal for the pipeline?
> What happens if I call mapperB->Unregister(0) ?
> Where is difference between Unregister(..) and Delete()?
>
> Thanks a lot,
>
> Sebastian Barth
>
>
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