Last modified: 20 May 2010
Name: H5Pset_edc_check
Signature:
  herr_t `H5Pset_edc_check`( hid_t `plist`, H5Z_EDC_t `check` )

Purpose:
  Sets whether to enable error-detection when reading a dataset.

Description:
  `H5Pset_edc_check` sets the dataset transfer property list `plist` to enable or disable error detection when reading data.

  Whether error detection is enabled or disabled is specified in the `check` parameter. Valid values are as follows:

  | `H5Z_ENABLE_EDC` (default) `H5Z_DISABLE_EDC`

  The error detection algorithm used is the algorithm previously specified in the corresponding dataset creation property list.

  This function does not affect the use of error detection when writing data.

Note:
  The initial error detection implementation, Fletcher32 checksum, supports error detection for chunked datasets only.

Note:
  The Fletcher32 EDC checksum filter, set with `H5Pset_fletcher32`, was added in HDF5 Release 1.6.0. In the original implementation, however, the checksum value was calculated incorrectly on little-endian systems. The error was fixed in HDF5 Release 1.6.3.

  As a result of this fix, an HDF5 Library of Release 1.6.0 through Release 1.6.2 cannot read a dataset created or written with Release 1.6.3 or later if the dataset was created with the checksum filter and the filter is enabled in the reading library. (Libraries of Release 1.6.3 and later understand the earlier error and comensate appropriately.)

  Work-around: An HDF5 Library of Release 1.6.2 or earlier will be able to read a dataset created or written with the checksum filter by an HDF5 Library of Release 1.6.3 or later if the checksum filter is disabled for the read operation. This can be accomplished via an `H5Pset_edc_check` call with the value `H5Z_DISABLE_EDC` in the second parameter. This has the obvious drawback that the application will be unable to verify the checksum, but the data does remain accessible.

Parameters:

hid_t `plist` | IN: Dataset transfer property list identifier.
H5Z_EDC_t `check` | IN: Specifies whether error checking is enabled or disabled for dataset read operations.

Returns:
  Returns a non-negative value if successful; otherwise returns a negative value.

Fortran90 Interface: h5pset_edc_check_f

      SUBROUTINE h5pset_edc_check_f(prp_id, flag, hdferr)
        IMPLICIT NONE
        INTEGER(HID_T), INTENT(IN) :: prp_id   ! Dataset transfer property
                                               ! list identifier
        INTEGER, INTENT(IN)        :: flag     ! EDC flag; possible values
                                               !    H5Z_DISABLE_EDC_F
                                               !    H5Z_ENABLE_EDC_F
        INTEGER, INTENT(OUT)       :: hdferr   ! Error code
                                               ! 0 on success and -1 on failure

      END SUBROUTINE h5pset_edc_check_f

History:

Release | Change
1.6.0 | Function introduced in this release.
1.6.3 | Error in checksum calculation on little-endian systems corrected in this release.