message: added scalar variable for testing
diff: @@ -27,6 +27,7 @@ int main(int argc, char *argv[])
  /** Application variable */
  std::vector<float> myFloats = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
  std::vector<int> myInts = {0, -1, -2, -3, -4, -5, -6, -7, -8, -9};
  + double myScalar = 1.234;
  const std::size_t Nx = myFloats.size();
  try
  @@ -47,6 +48,7 @@ int main(int argc, char *argv[])
  adios2::Variable<int> h5Ints = hdf5IO.DefineVariable<int>(
  "h5Ints", {size * Nx}, {rank * Nx}, {Nx}, adios2::ConstantDims);
  + adios2::Variable<double> h5ScalarDouble = hdf5IO.DefineVariable<double>("h5ScalarDouble");
  /** Engine derived class, spawned to start IO operations */
  adios2::Engine hdf5Writer =
  hdf5IO.Open("myVector.h5", adios2::Mode::Write);
  @@ -54,6 +56,7 @@ int main(int argc, char *argv[])
  /** Write variable for buffering */
  hdf5Writer.Put<float>(h5Floats, myFloats.data());
  hdf5Writer.Put(h5Ints, myInts.data());
  + hdf5Writer.Put(h5ScalarDouble, &myScalar);
  std::vector<int64_t> m_globalDims = {10, 20, 30, 40};
  hdf5IO.DefineAttribute<std::string>(
  