Signature:
  SUBROUTINE h5pget_virtual_srcspace_f(dcpl_id, index, ds_id, hdferr)
    INTEGER(HID_T) , INTENT(IN)  :: dcpl_id
    INTEGER(SIZE_T), INTENT(IN)  :: index
    INTEGER(HID_T) , INTENT(OUT) :: ds_id
    INTEGER, INTENT(OUT)         :: hdferr
Inputs:
  dcpl_id - The identifier of the virtual dataset creation property list.
  index   - Mapping index.
            The value of index is 0 (zero) or greater and less than count 
            (0 ≤ index < count), where count is the number of mappings 
            returned by h5pget_virtual_count.
Outputs:
  ds_id  - dataspace identifier
  hdferr - Returns 0 if successful and -1 if fails.