int sd_bus_add_object_vtable(sd_bus *bus, sd_bus_slot **slot, const char *path, const char *interface, const sd_bus_vtable *vtable, void *userdata);
int sd_bus_add_fallback_vtable(sd_bus *bus, sd_bus_slot **slot, const char *prefix, const char *interface, const sd_bus_vtable *vtable, sd_bus_object_find_t find, void *userdata);
int sd_bus_add_node_enumerator(sd_bus *bus, sd_bus_slot **slot, const char *path, sd_bus_node_enumerator_t callback, void *userdata);
int sd_bus_add_object_vtable(sd_bus *bus, sd_bus_slot **slot, const char *path, const char *interface, const sd_bus_vtable *vtable, void *userdata);
int sd_bus_add_fallback_vtable(sd_bus *bus, sd_bus_slot **slot, const char *prefix, const char *interface, const sd_bus_vtable *vtable, sd_bus_object_find_t find, void *userdata);
int sd_bus_add_node_enumerator(sd_bus *bus, sd_bus_slot **slot, const char *path, sd_bus_node_enumerator_t callback, void *userdata);