H5Literate
(
hid_t group_id
,
H5_index_t index_type
,
H5_iter_order_t order
,
hsize_t *idx
,
H5L_iterate_t op
,
void *op_data
)
H5Literate
iterates through the links
in a group, specified by group_id
,
in the order of the specified index, index_type
,
using a user-defined callback routine op
.
H5Literate
does not recursively follow links into
subgroups of the specified group.
Three parameters are used to manage progress of the iteration:
index_type
, order
, and idx
.
index_type
specifies the index to be used.
If the links have not been indexed by the index type, they will first
be sorted by that index then the iteration will begin;
if the links have been so indexed, the sorting step will be
unnecesary, so the iteration may begin more quickly.
Valid values include the following:
H5_INDEX_NAME
| Alpha-numeric index on name | |
H5_INDEX_CRT_ORDER
| Index on creation order |
order
specifies the order in which objects are to be
inspected along the index specified in index_type
.
Valid values include the following:
H5_ITER_INC
| Increasing order | |
H5_ITER_DEC
| Decreasing order | |
H5_ITER_NATIVE
| Fastest available order |
idx
allows an interrupted iteration to be resumed;
it is passed in by the application with a starting point and
returned by the library with the point at which the iteration stopped.
The op
callback function,
the related H5L_info_t struct,
and the effect of the callback function’s return value
on the application are described in
H5Lvisit
.
op_data
is a user-defined pointer to the data required
to process links in the course of the iteration.
This pointer is passed back to each step of the iteration in the
op
callback function’s op_data
parameter.
As mentioned above, H5Literate
is not recursive.
In particular, if a member of group_id
is found to be
a group, call it subgroup_a
, H5Literate
does not examine the members of subgroup_a
.
When recursive iteration is required, the application can
do either of the following:
H5Literate
:
H5Lvisit
H5Lvisit_by_name
H5Ovisit
H5Ovisit_by_name
H5Literate
on discovered subgroups.
H5Literate
assumes that the membership of the group
being iterated over remains unchanged through the iteration;
if any of the links in the group change during the iteration,
the function’s behavior is undefined.
Note, however, that objects pointed to by the links can be modified.
H5Literate
is the same as deprecated function
H5Giterate
, except that H5Giterate
always
proceeded in alphanumeric order.
If a C routine that takes a function pointer as an argument is called from within C++ code, the C routine should be returned from normally.
Examples of this kind of routine include callbacks such as
H5Pset_elink_cb
and H5Pset_type_conv_cb
and functions such as H5Tconvert
and
H5Ewalk2
.
Exiting the routine in its normal fashion allows the HDF5 C Library to clean up its work properly. In other words, if the C++ application jumps out of the routine back to the C++ “catch” statement, the library is not given the opportunity to close any temporary data structures that were set up when the routine was called. The C++ application should save some state as the routine is started so that any problem that occurs might be diagnosed.
hid_t group_id |
IN: Identifier specifying subject group |
H5_index_t index_type |
IN: Type of index which determines the order |
H5_iter_order_t order |
IN: Order within index |
hsize_t *idx |
IN: Iteration position at which to start
OUT: Position at which an interrupted iteration may be restarted |
H5L_iterate_t op |
IN: Callback function passing data regarding the link to the calling application |
void *op_data |
IN: User-defined pointer to data required by the application for its processing of the link |
On failure, returns a negative value if something goes wrong within the library, or the first negative value returned by an operator.
Release | Change |
1.8.8 | Fortran subroutine added. |
1.8.0 | C function introduced. |