NAME

       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

       #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

       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

       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.

NOTES

       These APIs are implemented as a shared library, which can be compiled and linked to with the
       libsystemd pkg-config(1) file.

SEE ALSO

       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)

systemd 249                                                                                SD_BUS_EMIT_SIGNAL(3)