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H5T_GET_NATIVE_TYPE

Returns the native datatype of a specified datatype.

Procedure:

H5T_GET_NATIVE_TYPE(dtype_id, direction)

Signature:

hid_t H5Tget_native_type( hid_t dtype_id, H5T_direction_t direction )

SUBROUTINE h5tget_native_type_f(dtype_id, direction, native_dtype_id, hdferr)
  IMPLICIT NONE
  INTEGER(HID_T), INTENT(IN) :: dtype_id  
                                    ! Datatype identifier
  INTEGER, INTENT(IN) :: direction  ! Direction of search:
                                    ! H5T_DIR_ASCEND_F = 1 in inscendent order
                                    ! H5T_DIR_DESCEND_F= 2 in descendent order
  INTEGER(HID_T), INTENT(OUT) :: native_dtype_id  
                                    ! The native datatype identifier
  INTEGER, INTENT(OUT) :: hdferr    ! Error code:
                                    ! 0 on success and -1 on failure
END SUBROUTINE h5tget_native_type_f

Parameters:
hid_t dtype_idIN: Datatype identifier for the dataset datatype.
H5T_direction_t direction    IN: Direction of search.

Description:

H5Tget_native_type returns the equivalent native datatype for the datatype specified in dtype_id.

H5Tget_native_type is a high-level function designed primarily to facilitate use of the H5Dread function, for which users otherwise must undertake a multi-step process to determine the native datatype of a dataset prior to reading it into memory. This function can be used for the following purposes:

  • To determine the native datatype of an atomic datatype
  • To determine the base datatype of an array, enumerated, or variable-length datatype
  • To determine the native atomic datatypes of the individual components of a compound datatype

For example, if dtype_id is a compound datatype, the returned datatype identifier will be for a similar compound datatype with each element converted to the corresponding native datatype; nested compound datatypes will be unwound. If dtype_id is an array, the returned datatype identifier will be for the native datatype of a single array element.

H5Tget_native_type selects the first matching native datatype from the following list:

        H5T_NATIVE_CHAR         
        H5T_NATIVE_SHORT        
        H5T_NATIVE_INT          
        H5T_NATIVE_LONG         
        H5T_NATIVE_LLONG        

        H5T_NATIVE_UCHAR
        H5T_NATIVE_USHORT
        H5T_NATIVE_UINT
        H5T_NATIVE_ULONG
        H5T_NATIVE_ULLONG

        H5T_NATIVE_FLOAT
        H5T_NATIVE_DOUBLE
        H5T_NATIVE_LDOUBLE

        H5T_NATIVE_B8
        H5T_NATIVE_B16
        H5T_NATIVE_B32
        H5T_NATIVE_B64

The direction parameter indicates the order in which the library searches for a native datatype match. Valid values for direction are as follows:

    H5T_DIR_ASCENDSearches the above list in ascending size of the datatype,
i.e., from top to bottom. (Default)
 H5T_DIR_DESCEND  Searches the above list in descending size of the datatype,
i.e., from bottom to top.

H5Tget_native_type is designed primarily for use with integer, floating point, and bitfield datatypes. String, time, opaque, and reference datatypes are returned as a copy of dtype_id. See above for compound, array, enumerated, and variable-length datatypes.

The identifier returned by H5Tget_native_type should eventually be closed by calling H5Tclose to release resources.

Returns:

Returns the native datatype identifier for the specified dataset datatype if successful; otherwise returns a negative value.

Example:

Coming Soon!

History:
Release    C
1.6.0Function introduced in this release.

--- Last Modified: December 04, 2017 | 07:00 AM