Last modified: 24 August 2012
Name: H5Literate
Signature:
herr_t 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 )

Purpose:
Iterates through links in a group.

Description:
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 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.

Programming Note for C++ Developers Using C Functions:

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.

Parameters:
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

Returns:
On success, returns the return value of the first operator that returns a positive value, or zero if all members were processed with no operator returning non-zero.

On failure, returns a negative value if something goes wrong within the library, or the first negative value returned by an operator.

Fortran2003 Interface: h5literate_f

History:
Release     Change
1.8.8 Fortran subroutine added.
1.8.0 C function introduced.