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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON |
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SD_BUS_ADD_NODE_ENUMERATOR(3)_add_node_enumerator_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
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).
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.
These APIs are implemented as a shared library, which can be
compiled and linked to with the libsystemd pkg-config(1) file.
sd-bus(3), busctl(1), sd_bus_add_fallback_vtable(3),
sd_bus_slot_unref(3)
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
time, the date of the most recent commit that was found in the
repository was 2021-04-01.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 248 SD_BUS_ADD_NODE_ENUMERATOR(3)
Pages that refer to this page: sd-bus(3), systemd.directives(7), systemd.index(7)
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