!
!   This example creates region refernces to the selections in the 'SatelliteZenithAngle'
!   'SatelliteAzimuthAngle' and 'SatelliteRange' datsets under '/All_Data/VIIRS-MOD-GTM-EDR-GEO_All'
!   and writes it to the 'Satellite' dataset located in the  '/Data_Products' group. 
!   Main illustrative functions: H5LRcreate_region_references_f
!
PROGRAM main

  USE ISO_C_BINDING
  USE HDF5 ! module of HDF5 library
  USE H5LT ! module of H5LT
  USE H5HL_REGION

  IMPLICIT NONE

  CHARACTER(LEN=78), PARAMETER :: filename = &
       "GMGTO_npp_d20030125_t0657104_e0659047_b00014_c20090811150425926728_unkn_SCI.h5"

  INTEGER(hid_t) :: file_id  ! file identifier
  ! hyperslab coordinates, (52,4)-(54,8) in each of the 'SatelliteZenithAngle', 'SatelliteAzimuthAngle', 'SatelliteRange' datsets
  INTEGER(hsize_t), DIMENSION(1:12) :: block_coord = (/52,4,54,8,52,4,54,8,52,4,54,8/) 
  TYPE(hdset_reg_ref_t_f), DIMENSION(1:3) ::  ref ! region references to hyperslabs of 'SatelliteZenithAngle', 'SatelliteAzimuthAngle', 'SatelliteRange'
  CHARACTER(LEN=80), DIMENSION(1:3) :: path ! full paths to the satellite target datasets for the region references!
  INTEGER(hsize_t), DIMENSION(1:1) :: dims = (/3/)
  INTEGER(HID_T) :: space_id     ! Dataspace identifier
  INTEGER(HID_T) :: dset_id      ! Dataset identifier
  INTEGER :: status

  path(1)= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteZenithAngle"
  path(2)= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteAzimuthAngle"
  path(3)= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteRange"
  !
  !  Initialize FORTRAN interface.
  !
  CALL H5open_f(status)
  !
  ! Open the NPP file.
  !
  CALL H5Fopen_f(filename, H5F_ACC_RDWR_F, file_id, status)
  !
  ! Create three region references pointing to hyperslabs with block coordinates (52,4)-(54,8) in
  ! 'SatelliteZenithAngle', 'SatelliteAzimuthAngle' and 'SatelliteRange' datasets. 
  !
  CALL H5LRcreate_region_references_f(file_id, 3_size_t, path, block_coord, ref, status)

  ! 
  ! I. Create a dataset with the region references.
  !
  !   (a) Create dataspace for dataset with references to dataset regions
  !
  CALL H5Screate_simple_f(1, dims, space_id, status)
  !
  !   (b) Create dataset with references
  !
  CALL H5Dcreate_f(file_id, "/Data_Products/Satellite", H5T_STD_REF_DSETREG, space_id, &
       dset_id, status)
  !
  !   (c) Write dataset with references
  !
  CALL H5Dwrite_f(dset_id, H5T_STD_REF_DSETREG, ref, dims, status)

  CALL H5Sclose_f(space_id, status)
  CALL H5Dclose_f(dset_id, status)
  CALL H5Fclose_f(file_id, status)

END PROGRAM main