sd_bus_add_node_enumerator(3) — Linux manual page



NAME         top

       sd_bus_add_node_enumerator - Add a node enumerator for a D-Bus object
       path prefix

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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 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

       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         top

       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:

           One of the required parameters is NULL or path is not a valid
           object path.

           The bus cannot be resolved.

           The bus was created in a different process.

           Memory allocation failed.

NOTES         top

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

SEE ALSO         top

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

COLOPHON         top

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systemd 246                                    SD_BUS_ADD_NODE_ENUMERATOR(3)

Pages that refer to this page: sd-bus(3)30-systemd-environment-d-generator(7)systemd.directives(7)systemd.index(7)