H5G_GET_OBJNAME_BY_IDX returns a name of the object specified by the index
idx in the group
The group is specified by a group identifier
loc_id. If preferred, a file identifier may be passed in
loc_id; that file's root group will be assumed.
idx is the transient index used to iterate through the objects in the group. The value of
idx is any nonnegative number less than the total number of objects in the group, which is returned by the function H5G_GET_NUM_OBJS. Note that this is a transient index; an object may have a different index each time a group is opened.
The object name is returned in the user-specified buffer
If the size of the provided buffer
name is less or equal the actual object name length, the object name is truncated to
max_size - 1 characters.
Note that if the size of the object's name is unkown, a preliminary call to H5G_GET_OBJNAME_BY_IDX with
name set to NULL will return the length of the object's name. A second call to H5G_GET_OBJNAME_BY_IDX can then be used to retrieve the actual name.