static char help[] = "Demonstrates PetscMatlabEngineXXX()\n";

#include <petscsys.h>
#include <petscmatlab.h>

int main(int argc, char **argv)
{
  PetscMPIInt rank;
  char        buffer[256], *output, user[256];
  PetscBool   userhappy = PETSC_FALSE;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

  PetscCall(PetscMatlabEngineGetOutput(PETSC_MATLAB_ENGINE_(PETSC_COMM_WORLD), &output));

  PetscCall(PetscMatlabEngineEvaluate(PETSC_MATLAB_ENGINE_(PETSC_COMM_WORLD), "MPI_Comm_rank"));
  PetscCall(PetscSynchronizedPrintf(PETSC_COMM_WORLD, "[%d]Processor rank is %s", rank, output));
  PetscCall(PetscSynchronizedFlush(PETSC_COMM_WORLD, PETSC_STDOUT));
  PetscCall(PetscPrintf(PETSC_COMM_WORLD, ">>"));
  PetscCall(PetscSynchronizedFGets(PETSC_COMM_WORLD, stdin, 256, user));
  PetscCall(PetscStrncmp(user, "exit", 4, &userhappy));
  while (!userhappy) {
    PetscCall(PetscMatlabEngineEvaluate(PETSC_MATLAB_ENGINE_(PETSC_COMM_WORLD), user));
    PetscCall(PetscSynchronizedPrintf(PETSC_COMM_WORLD, "[%d]The result is %s", rank, output));
    PetscCall(PetscSynchronizedFlush(PETSC_COMM_WORLD, PETSC_STDOUT));
    PetscCall(PetscPrintf(PETSC_COMM_WORLD, ">>"));
    PetscCall(PetscSynchronizedFGets(PETSC_COMM_WORLD, stdin, 256, user));
    PetscCall(PetscStrncmp(user, "exit", 4, &userhappy));
  }
  PetscCall(PetscFinalize());
  return 0;
}