<para><parameter>callback</parameter> is called with the path and userdata pointer registered
with <function>sd_bus_add_node_enumerator()</function>. When called, it should store all the
- child object paths of the given path prefix in <parameter>ret_nodes</parameter> and return the
- number of child objects under the given prefix. If an error occurs, it can either return a
+ child object paths of the given path prefix in <parameter>ret_nodes</parameter> with a NULL
+ terminator item. The callback should return a non-negative value on success.
+ If an error occurs, it can either return a
negative integer, set <parameter>ret_error</parameter> to a non-empty error or do both. Any
errors returned by the callback are encoded as D-Bus errors and sent back to the caller. Errors
in <parameter>ret_error</parameter> take priority over negative return values.</para>