Decrements the reference count for an object
Procedure:
Signature:
int H5Idec_ref( hid_t obj_id )
SUBROUTINE h5idec_ref_f(obj_id, ref_count, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: obj_id !Object identifier
INTEGER, INTENT(OUT) :: ref_count !Reference count of object identifier
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success, and -1 on failure
END SUBROUTINE h5idec_ref_f
Parameters:
hid_t obj_id | IN: Object identifier whose reference count will be modified |
Description:
H5I_DEC_REF decrements the reference count of the object identified by obj_id.
The reference count for an object identifier is attached to the information about an object in memory and has no relation to the number of links to an object on disk.
The reference count for a newly created object will be 1. Reference counts for objects may be explicitly modified with this function or with H5I_INC_REF. When an object identifier’s reference count reaches zero, the object will be closed. Calling an object identifier’s CLOSE function decrements the reference count for the identifier which normally closes the object, but if the reference count for the identifier has been incremented with H5I_INC_REF, the object will only be closed when the reference count reaches zero with further calls to this function or the object identifier’s CLOSE function.
If the object identifier was created by a collective parallel call (such as H5D_CREATE, H5G_OPEN, etc.), the reference count should be modified by all the processes which have copies of the identifier. Generally this means that group, dataset, attribute, file, and committed datatype identifiers should be modified by all the processes and that all other types of identifiers are safe to modify by individual processes.
This function is of particular value when an application is maintaining multiple copies of an object identifier. The object identifier can be incremented when a copy is made. Each copy of the identifier can then be safely closed or decremented and the HDF5 object will be closed when the reference count for that that object drops to zero.
Returns:
Returns a non-negative reference count of the object identifier after decrementing it, if successful; otherwise a negative value is returned.
Example:
History:
| Release | Change |
|---|
| 1.6.2 | Function introduced in this release.
Fortran subroutine introduced in this release. |
--- Last Modified: April 25, 2019 | 12:00 PM
