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.
Returned errors may indicate the following problems:
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)