sd_bus_add_node_enumerator(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_BUS_ADD_NODE_ENUMERATOR(3)_add_node_enumerator_ADD_NODE_ENUMERATOR(3)

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
       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         top

       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         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),
       sd_bus_slot_unref(3)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-04-01.  (At that
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       (which is not part of the original manual page), send a mail to
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systemd 248                                SD_BUS_ADD_NODE_ENUMERATOR(3)

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