message: fix: only delete array if it was allocated
diff: @@ -81,7 +81,7 @@ int main(int argc, char *argv[])
  adios2::Engine &bpReader = bpReaderIO.Open(
  settings.inputfile, adios2::Mode::Read, mpiReaderComm);
  - double *T;
  + double *T = nullptr;
  adios2::Variable<double> *vT = nullptr;
  bool firstStep = true;
  int step = 0;
  @@ -138,6 +138,7 @@ int main(int argc, char *argv[])
  step++;
  }
  bpReader.Close();
  + if (!T)
  delete[] T;
  }
  catch (std::invalid_argument &e) // command-line argument errors
  