message: fixed a size_t / uint64_t problem for macOS 10.12 and Clang 8.1.0
diff: @@ -95,6 +95,8 @@ int main(int argc, char *argv[])
  // 1D decomposition of the columns, which is inefficient for reading!
  std::vector<uint64_t> readsize({gndx, gndy / nproc});
  std::vector<uint64_t> offset({0LL, rank * readsize[1]});
  + std::vector<size_t> readsize_size_t({gndx, gndy / nproc});
  + std::vector<size_t> offset_size_t({0LL, rank * readsize[1]});
  if (rank == nproc - 1)
  {
  // last process should read all the rest of columns
  @@ -109,7 +111,7 @@ int main(int argc, char *argv[])
  double *T = new double[vT->m_AvailableSteps * readsize[0] * readsize[1]];
  // Create a 2D selection for the subset
  - vT->SetSelection(offset, readsize);
  + vT->SetSelection(offset_size_t, readsize_size_t);
  vT->SetStepSelection(0, vT->m_AvailableSteps);
  // Arrays are read by scheduling one or more of them
  