ExternalProblem - forward declaration error

[mcacace]

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Question

Dear all,
I'm having some difficult time troubleshooting a forward declaration error while inheriting from ExternalProblem and trying to get a reference to the AuxiliarySystem (from FEProblemBase).
I have a system of auxvariables (which I add to the problem inside the addExternalVariables function) and I would like to initialize and update their values based on the results from an external code. However, if I try to get access to the solution vector (_aux->solution()) the code throws me the forward declaration error, which I do not understand since FEProblemBase should be public via inheritance from ExternalProblem. On a side note, if I follow the approach from the available module externalPetscSolverApp I can access the solution vector with no error (via SystemBase). What am I doing wrong? Thanks for any hint

[mcacace]

problem solved. Sorry for posting in a rush.