Last modified: 18 August 2010
Name: H5Tget_offset
Signature:
  int `H5Tget_offset`( hid_t `dtype_id` )

Purpose:
  Retrieves the bit offset of the first significant bit.

Description:
  `H5Tget_offset` retrieves the bit offset of the first significant bit. The significant bits of an atomic datum can be offset from the beginning of the memory for that datum by an amount of padding. The `offset' property specifies the number of bits of padding that appear to the "right of" the value. That is, if we have a 32-bit datum with 16-bits of precision having the value 0x1122 then it will be laid out in memory as (from small byte address toward larger byte addresses):

  Byte Position | Big-Endian Offset=0 | Big-Endian Offset=16 | Little-Endian Offset=0 | Little-Endian Offset=16
  --- | --- | --- | --- | ---
  0: | [ pad] | [0x11] | [0x22] | [ pad]
  1: | [ pad] | [0x22] | [0x11] | [ pad]
  2: | [0x11] | [ pad] | [ pad] | [0x22]
  3: | [0x22] | [ pad] | [ pad] | [0x11]

Parameters:

  hid_t `dtype_id` | IN: Identifier of datatype to query.

Returns:
  Returns an offset value if successful; otherwise returns a negative value.

Fortran90 Interface: h5tget_offset_f

      SUBROUTINE h5tget_offset_f(type_id, offset, hdferr)
        IMPLICIT NONE
        INTEGER(HID_T), INTENT(IN) :: type_id  ! Datatype identifier
        INTEGER(SIZE_T), INTENT(OUT) :: offset ! Datatype bit offset of the
                                               ! first significant bit
        INTEGER, INTENT(OUT) :: hdferr         ! Error code
                                               ! 0 on success and -1 on failure
      END SUBROUTINE h5tget_offset_f