|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON |
SD_BUS_EMIT_SIGNAL(3) sd_bus_emit_signal SD_BUS_EMIT_SIGNAL(3)
sd_bus_emit_signal, sd_bus_emit_signalv,
sd_bus_emit_interfaces_added, sd_bus_emit_interfaces_added_strv,
sd_bus_emit_interfaces_removed, sd_bus_emit_interfaces_removed_strv,
sd_bus_emit_properties_changed, sd_bus_emit_properties_changed_strv,
sd_bus_emit_object_added, sd_bus_emit_object_removed - Convenience
functions for emitting (standard) D-Bus signals
#include <systemd/sd-bus-vtable.h>
int sd_bus_emit_signal(sd_bus *bus, const char *path,
const char *interface, const char *member,
const char *types, ...);
int sd_bus_emit_signalv(sd_bus *bus, const char *path,
const char *interface, const char *member,
const char *types, va_list ap);
int sd_bus_emit_interfaces_added(sd_bus *bus, const char *path,
const char *interface, ...);
int sd_bus_emit_interfaces_added_strv(sd_bus *bus, const char *path,
const char **interfaces);
int sd_bus_emit_interfaces_removed(sd_bus *bus, const char *path,
const char *interface, ...);
int sd_bus_emit_interfaces_removed_strv(sd_bus *bus,
const char *path,
const char **interfaces);
int sd_bus_emit_properties_changed(sd_bus *bus, const char *path,
const char *interface,
const char *name, ...);
int sd_bus_emit_properties_changed_strv(sd_bus *bus,
const char *path,
const char *interface,
const char **names);
int sd_bus_emit_object_added(sd_bus *bus, const char *path);
int sd_bus_emit_object_removed(sd_bus *bus, const char *path);
sd_bus_emit_signal() is a convenience function for initializing a bus
message object and emitting the corresponding D-Bus signal. It
combines the sd_bus_message_new_signal(3), sd_bus_message_append(3)
and sd_bus_send(3) functions into a single function call.
sd_bus_emit_signalv() is equivalent to sd_bus_message_append(),
except that it is called with a "va_list" instead of a variable
number of arguments.
sd_bus_emit_interfaces_added() and sd_bus_emit_interfaces_removed()
are used to implement the InterfacesAdded and InterfacesRemoved
signals of the org.freedesktop.DBus.ObjectManager interface. They
take a path whose interfaces have been modified as an argument and a
variable list of interfaces that have been added or removed,
respectively. The final argument passed to
sd_bus_emit_interfaces_added() and sd_bus_emit_interfaces_removed()
must be NULL. This allows both functions to safely determine the
number of passed interface arguments.
sd_bus_emit_interfaces_added_strv() and
sd_bus_emit_interfaces_removed_strv() are identical to their
respective counterparts but both take the list of interfaces as a
single argument instead of a variable number of arguments.
sd_bus_emit_properties_changed() is used to implement the
PropertiesChanged signal of the org.freedesktop.DBus.Properties
interface. It takes an object path, interface and a variable list of
property names as its arguments. The final argument passed to
sd_bus_emit_properties_changed() must be NULL. This allows it to
safely determine the number of passed property names.
sd_bus_emit_properties_changed_strv() is identical to
sd_bus_emit_properties_changed() but takes the list of property names
as a single argument instead of a variable number of arguments.
sd_bus_emit_object_added() and sd_bus_emit_object_removed() are
convenience functions for emitting the InterfacesAdded or
InterfacesRemoved signals for all interfaces registered on a specific
object path, respectively. This includes any parent fallback vtables
if they are not overridden by a more applicable child vtable. It also
includes all the standard D-Bus interfaces implemented by sd-bus
itself on any registered object.
Note that sd_bus_emit_interfaces_added(),
sd_bus_emit_interfaces_removed(), sd_bus_emit_object_added() and
sd_bus_emit_object_removed() require an object manager to have been
registered on the given object path or one of its parent object paths
using sd_bus_add_object_manager(3).
On success, these functions return a non-negative integer. On
failure, they return a negative errno-style error code.
Errors
Returned errors may indicate the following problems:
-EINVAL
One of the required parameters is NULL or invalid. A reserved
D-Bus interface was passed as the interface parameter.
-ENOPKG
The bus cannot be resolved.
-ECHILD
The bus was created in a different process.
-ENOMEM
Memory allocation failed.
-ESRCH
One of sd_bus_emit_interfaces_added(),
sd_bus_emit_interfaces_removed(), sd_bus_emit_object_added() or
sd_bus_emit_object_removed() was called on an object without an
object manager registered on its own object path or one of its
parent object paths.
See the man pages of sd_bus_message_new_signal(3),
sd_bus_message_append(3) and sd_bus_send(3) for more possible errors.
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_message_new_signal(3),
sd_bus_message_append(3), sd_bus_send(3), sd_bus_call_method(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 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) 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 246 SD_BUS_EMIT_SIGNAL(3)
Pages that refer to this page: sd-bus(3) , 30-systemd-environment-d-generator(7) , systemd.index(7)