sd_bus_emit_signalv(3) — Linux manual page


SD_BUS_EMIT_SIGNAL(3)        sd_bus_emit_signal        SD_BUS_EMIT_SIGNAL(3)

NAME         top

       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

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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).

RETURN VALUE         top

       On success, these functions return a non-negative integer. On
       failure, they return a negative errno-style error code.

       Returned errors may indicate the following problems:

           One of the required parameters is NULL or invalid. A reserved
           D-Bus interface was passed as the interface parameter.

           The bus cannot be resolved.

           The bus was created in a different process.

           Memory allocation failed.

           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.

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_message_new_signal(3),
       sd_bus_message_append(3), sd_bus_send(3), sd_bus_call_method(3)

COLOPHON         top

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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)