- Created by Barbara Jones, last modified on May 08, 2018
H5A_ITERATE2
Calls user-defined function for each attribute on an object
Procedure:
H5A_ITERATE2 ( obj_id, idx_type, order, n, op, op_data )
Signature:
herr_t H5Aiterate2(
hid_t obj_id,
H5_index_t idx_type,
H5_iter_order_t order,
hsize_t *n,
H5A_operator2_t op,
void *op_data,
)
Parameters:
hid_t obj_id | IN: Identifier for object to which attributes are attached; may be a group, dataset, or named datatype identifier |
H5_index_t idx_type | IN: Type of index |
H5_iter_order_t order | IN: Order in which to iterate over index |
hsize_t *n | IN/OUT: Initial and returned offset within index |
H5A_operator2_t op | IN: User-defined function to pass each attribute to |
void *op_data | IN/OUT: User data to pass through to and to be returned by iterator operator function |
Description:
H5A_ITERATE2 iterates over the attributes attached to a dataset, named datatype, or group, as specified by obj_id. For each attribute, user-provided data, op_data, with additional information as defined below, is passed to a user-defined function, op, which operates on that attribute.
The order of the iteration and the attributes iterated over are specified by three parameters: the index type, idx_type; the order in which the index is to be traversed, order; and the attribute’s position in the index, n.
The type of index specified by idx_type can be one of the following:
H5_INDEX_NAME | An alpha-numeric index by attribute name |
H5_INDEX_CRT_ORDER | An index by creation order |
The order in which the index is to be traversed, as specified by order, can be one of the following:
H5_ITER_INC | Iteration is from beginning to end, i.e., a top-down iteration incrementing the index position at each step. |
H5_ITER_DEC | Iteration starts at the end of the index, i.e., a bottom-up iteration decrementing the index position at each step. |
H5_ITER_NATIVE | HDF5 iterates in the fastest-available order. No information is provided as to the order, but HDF5 ensures that each element in the index will be visited if the iteration completes successfully. |
The next attribute to be operated on is specified by n, a position in the index.
For example, if idx_type, order, and n are set to H5_INDEX_NAME, H5_ITER_INC, and 5, respectively, the attribute in question is the fifth attribute from the beginning of the alpha-numeric index of attribute names. If order were set to H5_ITER_DEC, it would be the fifth attribute from the end of the index.
The parameter n is passed in on an H5A_ITERATE2 call with one value and may be returned with another value. The value passed in identifies the parameter to be operated on first; the value returned identifies the parameter to be operated on in the next step of the iteration.
The H5A_operator2_t prototype for the op parameter is as follows:
H5A_operator2_t)( hid_t location_id/*in*/, const char *attr_name/*in*/, const H5A_info_t *ainfo/*in*/, void *op_data/*in,out*/)The operation receives the location identifier for the group or dataset being iterated over, location_id; the name of the current object attribute, attr_name; the attribute’s info struct, ainfo; and a pointer to the operator data passed into H5Aiterate2, op_data.
Valid return values from an operator and the resulting H5A_ITERATE2 and op behavior are as follows:
- Zero causes the iterator to continue, returning zero when all attributes have been processed.
- A positive value causes the iterator to immediately return that positive value, indicating short-circuit success. The iterator can be restarted at the next attribute, as indicated by the return value of
n. - A negative value causes the iterator to immediately return that value, indicating failure. The iterator can be restarted at the next attribute, as indicated by the return value of
n.
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Further note that this function returns the return value of the last operator if it was non-zero, which can be a negative value, zero if all attributes were processed, or a positive value indicating short-circuit success (see above).
Example:
Include Bitbucket Server for Confluence: An error occured
Connection to Bitbucket Server could not be established. Verify that you have properly configured the Bitbucket Server application link for your Confluence space and that your Bitbucket Server instance is up and running. Error details: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
History:
| Release | C |
| 1.8.0 | Function introduced in this release. |
--- Last Modified: May 08, 2018 | 10:14 AM