[Paraview] Segmentation Fault when using the vtkPVDReader

[Bogdan Daqui Herrera]

Hi Seb,

Thanks for the quick reply. Yes the project is managed with CMake. I have not however been able to find the relevant posts by Marcus (in the users list). Is
that in the users or developers mailing list?

It does sound like it could be a problem with some initialization, as you can see below.

One short update, it looks like setting ForceMultiBlockDataSet Output with:
pReader->SetForceOutputTypeToMultiBlock(1);
leads to the segmentation fault at Update() (The deepcopy is never reached). With or without setting the previous line, the error
vtkPVDReader (0x1cb49e0): Error creating "vtkXMLMultiBlockDataReader" using vtkPVInstantiator.

The code looks like this now:
	vtkSmartPointer < vtkPVDReader > pReader = vtkSmartPointer < vtkPVDReader >::New();
	pReader->SetFileName("/some/file.pvd");
	pReader->Update(); (where the error is triggered)

Kind Regards,
Bogdan

On 10/23/2014 04:47 PM, Sebastien Jourdain wrote:
> Hi Bogdan,
> 
> here are some issue in your code:
> 
> vtkSmartPointer <vtkPVDReader> pReader = vtkPVDReader::New(); // <== Memory LEAK
> // Should be either
> // vtkNew<vtkPVDReader> pReader;
> // vtkSmartPointer<vtkPVDReader> pReader = vtkSmartPointer<vtkPVDReader>::New()
> 
> Then here on a "NULL" object you try to call a method.
> 
> vtkMultiBlockDataSet* pMultiBlockDataSet->DeepCopy(vtkMultiBlockDataSet::SafeDownCast(pReader->GetOutputDataObject(0)));
> 
> Should be something like that:
> 
> vtkNew< vtkMultiBlockDataSet > pMultiBlockDataSet;
> pMultiBlockDataSet->DeepCopy(vtkMultiBlockDataSet::SafeDownCast(pReader->GetOutputDataObject(0)));
> 
> Then you might have some other issue where pReader output being empty/null, but for that I don't know.
> 
> Are you managing your project with CMake? Did you include the necessary file with the proper dependency declaration. This seems to be related to the factory not
> being properly initialized. You can search the mailing list, Marcus did answer several questions about that.
> 
> Seb
> 
> 
> 
> On Thu, Oct 23, 2014 at 7:26 AM, Bogdan Daqui Herrera <bdaqui at simscale.de <mailto:bdaqui at simscale.de>> wrote:
> 
>     Hello all,
> 
>     I am attempting to write some code in c++ which uses the vtkPVDReader from the paraview library to read a series of vtm files. However I am encountering some
>     problems and I am not sure whether there is something I am missing or whether this could be a bug.
> 
>     I am trying to use the reader in the following manner:
>     My Code:
>             vtkSmartPointer <vtkPVDReader> pReader = vtkPVDReader::New();
>             pReader->SetForceOutputTypeToMultiBlock(1);
>             pReader->SetFileName("/some/fileName.pvd");
>             pReader->Update();
>             vtkMultiBlockDataSet* pMultiBlockDataSet->DeepCopy(vtkMultiBlockDataSet::SafeDownCast(pReader->GetOutputDataObject(0)));
> 
>     Error:
>             The error occurs at Update() with the following result:
>             ERROR: In /misc/dn47/SALOME/PRODUCTS/7x/opt/Ubuntu.13.10.64/7.4.0/tmp/ParaView-4.1.0_SRC/ParaViewCore/VTKExtensions/Default
>             /vtkXMLCollectionReader.cxx, line 316
>             vtkPVDReader (0x224d9e0): Error creating "vtkXMLMultiBlockDataReader" using vtkPVInstantiator.
>             Segmentation fault
> 
>     Possible error Source
>     The code concerning line 316 from vtkXMLCollectionReader.cxx is:
> 
>           // Use the instantiator to create the reader.
>           vtkObject* o = vtkPVInstantiator::CreateInstance(rname);
>           vtkXMLReader* reader = vtkXMLReader::SafeDownCast(o);
>           this->Internal->Readers[index] = reader;
>           if(reader)
>             {
>             reader->Delete();
>             }
>           else
>             {
>             // The class was not registered with the instantiator.
>             vtkErrorMacro("Error creating \"" << rname
>                           << "\" using vtkPVInstantiator.");
>             if(o)
>               {
>               o->Delete();
>               }
>             }
>           }
> 
>     I have isolated the following lines and tested them independently:
>           vtkObject* o = vtkPVInstantiator::CreateInstance(rname);
>           vtkXMLReader* reader = vtkXMLReader::SafeDownCast(o);
> 
>     The pointer "vtkObject* o" is NULL regardless of the class name I pass to instantiate, and I can imagine something like that happening in the library, too and
>     causing the segmentation fault, when calling a SafeDownCast(o) (which is NULL).
> 
> 
>     Any suggestions on how to deal with this problem or if you would be so kind to point me to an example for an alternative solution (Could be vtkFileSeriesReader,
>     but this fails, as well in my case) would be appreciated.
> 
>     Kind Regards,
>     Bogdan
> 
>     P.S.: Using the PVDReader from python code works flawlessly, which is also quite confusing, as to why it would fail in the C++ code.
> 
>     --
>     Bogdan Daqui
>     Software Development
> 
>     SimScale GmbH
>     Lichtenbergstraße 8
>     85748 Garching bei München
> 
>     Phone: +49 (0)89 3398 4078
>     Email: bdaqui at simscale.de <mailto:bdaqui at simscale.de>
> 
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> 
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