systemd sd_bus_add_node_enumerator 3 sd_bus_add_node_enumerator Add a node enumerator for a D-Bus object path prefix #include <systemd/sd-bus.h> typedef int (*sd_bus_node_enumerator_t) sd_bus *bus const char *prefix void *userdata char ***ret_nodes sd_bus_error *ret_error int sd_bus_add_node_enumerator sd_bus *bus sd_bus_slot **slot const char *path sd_bus_node_enumerator_t callback void *userdata sd_bus_add_node_enumerator() adds a D-Bus node enumerator for the given path prefix. The given callback is called to enumerate all the available objects with the given path prefix when required (e.g. when org.freedesktop.DBus.Introspectable.Introspect or org.freedesktop.DBus.ObjectManager.GetManagedObjects are called on a D-Bus service managed by sd-bus). callback is called with the path and userdata pointer registered with sd_bus_add_node_enumerator(). When called, it should store all the child object paths of the given path prefix in ret_nodes 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 ret_error 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 ret_error take priority over negative return values. Note that a node enumerator callback will only ever be called for a single path prefix and hence, for normal operation, prefix can be ignored. Also, a node enumerator is only used to enumerate the available child objects under a given prefix. To install a handler for a set of dynamic child objects, use sd_bus_add_fallback_vtable3. When sd_bus_add_node_enumerator() succeeds, a slot is created internally. If the output parameter slot is NULL, a "floating" slot object is created, see sd_bus_slot_set_floating3. Otherwise, a pointer to the slot object is returned. In that case, the reference to the slot object should be dropped when the node enumerator is not needed anymore, see sd_bus_slot_unref3. On success, sd_bus_add_node_enumerator() returns a non-negative integer. On failure, it returns a negative errno-style error code. Returned errors may indicate the following problems: -EINVAL One of the required parameters is NULL or path is not a valid object path. -ENOPKG The bus cannot be resolved. -ECHILD The bus was created in a different process, library or module instance. -ENOMEM Memory allocation failed. sd_bus_node_enumerator_t() and sd_bus_add_node_enumerator() were added in version 246. sd-bus3, busctl1, sd_bus_add_fallback_vtable3, sd_bus_slot_unref3