#include <hdf5.h>
#include <mpi.h>

/* mpicc -Wall -O2 -o hdf5_compact_dset hdf5_compact_dset.c -lhdf5 */
int main(int argc, char **argv)
{
  int step, i;
  MPI_Init(&argc, &argv);
  hid_t fapl = H5Pcreate(H5P_FILE_ACCESS);
  H5Pset_fapl_mpio(fapl, MPI_COMM_WORLD, MPI_INFO_NULL);
  hid_t file = H5Fcreate("hdf5_compact_dset.h5", H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
  H5Pclose(fapl);
  hid_t space = H5Screate(H5S_SCALAR);
  hid_t dcpl = H5Pcreate(H5P_DATASET_CREATE);
  H5Pset_layout(dcpl, H5D_COMPACT);
  hid_t dset = H5Dcreate(file, "step", H5T_NATIVE_INT64, space, H5P_DEFAULT, dcpl, H5P_DEFAULT);
  H5Pclose(dcpl);
  for (i = 0; i < 100; ++i) {
    H5Dread(dset, H5T_NATIVE_INT, space, H5S_ALL, H5P_DEFAULT, &step);
  }
  H5Sclose(space);
  H5Dclose(dset);
  H5Fclose(file);
  MPI_Finalize();
}