[Dune] Weird behaviour of MPIHelper

[Martin Nolte]

Hi Aleksejs

you're returning a reference to a temporary, so weird behaviour is normal. To my 
knowledge, however, the compiler should emit a warning in this case. Did you 
disable / ignore them by accident?

Best,

Martin

On 05/19/2015 03:28 PM, Aleksejs Fomins wrote:
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> Dear Dune,
>
> I am having trouble with very basic c++ pointer problem in my curvilinear grid. The file grid.hh contains 2 functions:
>
>      const CollectiveCommunication &comm () const  { return mpihelper_.getCollectiveCommunication(); }
>
>      MPIHelper & mpihelper()  const { return mpihelper_; }
>
> One of them returns the MPIHelper reference, the other the CollectiveCommunication reference.
>
>
> I write a test program:
>
> Grid * grid = factory.createGrid();
>
> std::cout << "rank v1 = " << grid->comm().rank() << std::endl;
> std::cout << "rank v2 = " << grid->mpihelper().getCollectiveCommunication().rank() << std::endl;
>
> the result for a serial run is
> - -1183734688
> 0
>
> And the first result puzzles me a lot, as I expect it to be equal to the 2nd one. Otherwise, the grid is functioning well, so it is definitely initialized
>
> Any ideas?
>
> Greetings,
> Aleksejs
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-- 
Dr. Martin Nolte <nolte at mathematik.uni-freiburg.de>

Universität Freiburg                                   phone: +49-761-203-5630
Abteilung für angewandte Mathematik                    fax:   +49-761-203-5632
Hermann-Herder-Straße 10
79104 Freiburg, Germany