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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_A...UMERATOR(3) sd_bus_add_node_enumerator SD_BUS_A...UMERATOR(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
with a NULL terminator item. The callback should return a
non-negative value on success. 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, library or module
instance.
-ENOMEM
Memory allocation failed.
Functions described here are available as a shared library, which
can be compiled against and linked to with the
libsystemd pkg-config(1) file.
The code described here uses getenv(3), which is declared to be
not multi-thread-safe. This means that the code calling the
functions described here must not call setenv(3) from a parallel
thread. It is recommended to only do calls to setenv() from an
early phase of the program when no other threads have been
started.
sd_bus_node_enumerator_t() and sd_bus_add_node_enumerator() were
added in version 221.
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 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) 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
[email protected]
systemd 257~devel SD_BUS_A...UMERATOR(3)
Pages that refer to this page: sd-bus(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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