Function
Giobus_watch_name
since: 2.26
Declaration
guint
g_bus_watch_name (
GBusType bus_type,
const gchar* name,
GBusNameWatcherFlags flags,
GBusNameAppearedCallback name_appeared_handler,
GBusNameVanishedCallback name_vanished_handler,
gpointer user_data,
GDestroyNotify user_data_free_func
)
Description
Starts watching name on the bus specified by bus_type and calls
name_appeared_handler and name_vanished_handler when the name is
known to have an owner respectively known to lose its
owner. Callbacks will be invoked in the
[thread-default main context][g-main-context-push-thread-default]
of the thread you are calling this function from.
You are guaranteed that one of the handlers will be invoked after
calling this function. When you are done watching the name, just
call g_bus_unwatch_name() with the watcher id this function returns.
If the name vanishes or appears (for example the application owning
the name could restart), the handlers are also invoked. If the
GDBusConnection that is used for watching the name disconnects, then
name_vanished_handler is invoked since it is no longer
possible to access the name.
Another guarantee is that invocations of name_appeared_handler
and name_vanished_handler are guaranteed to alternate; that
is, if name_appeared_handler is invoked then you are
guaranteed that the next time one of the handlers is invoked, it
will be name_vanished_handler. The reverse is also true.
This behavior makes it very simple to write applications that want
to take action when a certain [name exists][gdbus-watching-names].
Basically, the application should create object proxies in
name_appeared_handler and destroy them again (if any) in
name_vanished_handler.
Available since: 2.26
The implementation of this method is provided by g_bus_watch_name_with_closures() in language bindings
Parameters
bus_type-
Type:
GBusTypeThe type of bus to watch a name on.
name-
Type:
const gchar*The name (well-known or unique) to watch.
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string. flags-
Type:
GBusNameWatcherFlagsFlags from the
GBusNameWatcherFlagsenumeration. name_appeared_handler-
Type:
GBusNameAppearedCallbackHandler to invoke when
nameis known to exist orNULL.The argument can be NULL. name_vanished_handler-
Type:
GBusNameVanishedCallbackHandler to invoke when
nameis known to not exist orNULL.The argument can be NULL. user_data-
Type:
gpointerUser data to pass to handlers.
The argument can be NULL.The data is owned by the caller of the function. user_data_free_func-
Type:
GDestroyNotifyFunction for freeing
user_dataorNULL.The argument can be NULL.