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There are several basic functions which inspect the buses for registered names. Internally they use the basic interface ‘org.freedesktop.DBus’, which is supported by all objects of a bus.
This function returns the D-Bus service names, which can be activated
for bus. It must be either the keyword :system
(the
default) or the keyword :session
. An activatable service is
described in a service registration file. Under GNU/Linux, such files
are located at /usr/share/dbus-1/system-services/ (for the
:system
bus) or /usr/share/dbus-1/services/. An
activatable service is not necessarily registered at bus
already.
The result is a list of strings, which is nil
when there are no
activatable service names at all. Example:
;; Check, whether the document viewer can be accessed via D-Bus. (member "org.gnome.evince.Daemon" (dbus-list-activatable-names :session))
This function returns all service names, which are registered at D-Bus
bus. The result is a list of strings, which is nil
when
there are no registered service names at all. Well known names are
strings like ‘org.freedesktop.DBus’. Names starting with
‘:’ are unique names for services.
bus must be either the keyword :system
or the keyword
:session
.
This function retrieves all registered services which correspond to a
known name in bus. A service has a known name if it doesn’t
start with ‘:’. The result is a list of strings, which is
nil
when there are no known names at all.
bus must be either the keyword :system
or the keyword
:session
.
For a given service, registered at D-Bus bus under the name
service, this function returns all queued unique names. The
result is a list of strings, or nil
when there are no queued
names for service at all.
bus must be either the keyword :system
or the keyword
:session
. service must be a known service name as
string.
For a given service, registered at D-Bus bus under the name
service, this function returns the unique name of the name
owner. The result is a string, or nil
when there is no name
owner of service.
bus must be either the keyword :system
or the keyword
:session
. service must be a known service name as
string.
This function checks whether the service name service is
registered at D-Bus bus. If service has not yet started,
it is autostarted if possible. The result is either t
or
nil
.
bus must be either the keyword :system
or the keyword
:session
. service must be a string. timeout, a
nonnegative integer, specifies the maximum number of milliseconds
before dbus-ping
must return. The default value is 25,000.
Example:
(message "%s screensaver on board." (cond ((dbus-ping :session "org.gnome.ScreenSaver" 100) "Gnome") ((dbus-ping :session "org.freedesktop.ScreenSaver" 100) "KDE") (t "No")))
To check whether service is already running without autostarting it, you can instead write:
(member service (dbus-list-known-names bus))
This function returns the unique name, under which Emacs is registered at D-Bus bus, as a string.
bus must be either the keyword :system
or the keyword
:session
.
Next: Knowing the details of D-Bus services., Previous: D-Bus version., Up: Inspection of D-Bus services. [Contents][Index]