добавить перечислитель узлов для префикса пути к объекту D-Bus (Add a node enumerator for a D-Bus object path prefix)
Имя (Name)
sd_bus_add_node_enumerator - Add a node enumerator for a D-Bus
object path prefix
Синопсис (Synopsis)
#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);
Описание (Description)
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).
Возвращаемое значение (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.
Примечание (Note)
These APIs are implemented as a shared library, which can be
compiled and linked to with the libsystemd pkg-config(1) file.
Смотри также (See also)
sd-bus(3), busctl(1), sd_bus_add_fallback_vtable(3),
sd_bus_slot_unref(3)
