SD_BUS_ADD_NODE_ENUMERATOR

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 and return the number of child objects under the given prefix. 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_vtable(3).

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_floating(3). 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_unref(3).  

RETURN VALUE

On success, sd_bus_add_node_enumerator() returns a non-negative integer. On failure, it returns a negative errno-style error code.  

Errors

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.

-ENOMEM

Memory allocation failed.

NOTES

These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.  

SEE ALSO

sd-bus(3), busctl(1), sd_bus_add_fallback_vtable(3), sd_bus_slot_unref(3)