Every XML file generated from h5view and h5dump will have the following XML header. An empty HDF5 file, showing the XML Header Table shows the XML description of an empty HDF5 file. An HDF5 file file always has a single root group. Table 1 is a complete and valid XML description of an HDF5 file. Group Element Objects in an HDF5 file are organized in Groups.
Objects can be shared, i.e., they can be members of more than one group.
In this case, the HDF5 file is a graph, not a tree, because some objects have more than one parent. It is also possible for Groups to directly or indirectly contain an ancestor. In other words, the graph can have a loop in it. Although XML is general enough to describe almost any structure, there are some limitation in representing the structure of an HDF5 file in a general set XML notation. Since H5View displays the structure of an HDF5 file as tree, the XML descriptions are trees, with exactly one root, and objects nested in their parent.