套件： dbus-user-session (1.12.16-2ubuntu2)

simple interprocess messaging system (systemd --user integration)

D-Bus is a message bus, used for sending messages between applications. Conceptually, it fits somewhere in between raw sockets and CORBA in terms of complexity.

On systemd systems, this package opts in to the session model in which a user's session starts the first time they log in, and does not end until all their login sessions have ended. This model merges all parallel non-graphical login sessions (text mode, ssh, cron, etc.), and up to one graphical session, into a single "user-session" or "super-session" within which all background D-Bus services are shared.

Multiple graphical sessions per user are not currently supported in this mode; as a result, it is particularly suitable for gdm, which responds to requests to open a parallel graphical session by switching to the existing graphical session and unlocking it.

To retain dbus' traditional session semantics, in which login sessions are artificially isolated from each other, remove this package and install dbus-x11 instead.

See the dbus package description for more information about D-Bus in general.