H5P_GET_ATTR_PHASE_CHANGE
Retrieves attribute storage phase change thresholds
Procedure:
H5P_GET_ATTR_PHASE_CHANGE ( ocpl_id, max_compact, min_dense )
Signature:
herr_t H5Pget_attr_phase_change(
hid_t ocpl_id,
unsigned *max_compact,
unsigned *min_dense
)
Fortran90 Interface: h5pget_attr_phase_change_f
SUBROUTINE h5pget_attr_phase_change_f(ocpl_id, max_compact, min_dense, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: ocpl_id
! Object (dataset or group) creation property list identifier
INTEGER, INTENT(OUT) :: max_compact
! Maximum number of attributes to be stored in compact storage
! (Default: 8)
INTEGER, INTENT(OUT) :: min_dense
! Minimum number of attributes to be stored in dense storage
! (Default: 6)
INTEGER, INTENT(OUT) :: hdferr
! Error code:
! 0 on success and -1 on failure
END SUBROUTINE h5pget_attr_phase_change_f
Parameters:
hid_t ocpl_id | IN: Object (dataset or group) creation property list identifier |
unsigned *max_compact | OUT: Maximum number of attributes to be stored in compact storage (Default: 8) |
unsigned *min_dense | OUT: Minimum number of attributes to be stored in dense storage (Default: 6) |
Description:
H5P_GET_ATTR_PHASE_CHANGE retrieves threshold values for attribute storage on an object. These thresholds determine the point at which attribute storage changes from compact storage (i.e., storage in the object header) to dense storage (i.e., storage in a heap and indexed with a B-tree).
In the general case, attributes are initially kept in compact storage. When the number of attributes exceeds max_compact, attribute storage switches to dense storage. If the number of attributes subsequently falls below min_dense, the attributes are returned to compact storage.
If max_compact is set to 0 (zero), dense storage always used.
ocpl_id is a dataset or group creation property list identifier. The term ocpl, for object creation property list, is used when different types of objects may be involved.
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Example:
History:
| Release | Change |
|---|
| 1.8.0 | Function introduced in this release. |
--- Last Modified: June 27, 2019 | 03:30 PM
