Owning Bus Names: GIO Reference Manual

Owning Bus Names

Owning Bus Names — Simple API for owning bus names

Functions

void	(*GBusAcquiredCallback) ()
void	(*GBusNameAcquiredCallback) ()
void	(*GBusNameLostCallback) ()
guint	g_bus_own_name ()
guint	g_bus_own_name_on_connection ()
void	g_bus_unown_name ()
guint	g_bus_own_name_with_closures ()
guint	g_bus_own_name_on_connection_with_closures ()

Types and Values

enum	GBusNameOwnerFlags

Includes

#include <gio/gio.h>

Description

Convenience API for owning bus names.

A simple example for owning a name can be found in gdbus-example-own-name.c

Functions

GBusAcquiredCallback ()

void
(*GBusAcquiredCallback) (GDBusConnection *connection,
                         const gchar *name,
                         gpointer user_data);

Invoked when a connection to a message bus has been obtained.

Parameters

connection	The GDBusConnection to a message bus.
name	The name that is requested to be owned.
user_data	User data passed to `g_bus_own_name()`.

Since 2.26

GBusNameAcquiredCallback ()

void
(*GBusNameAcquiredCallback) (GDBusConnection *connection,
                             const gchar *name,
                             gpointer user_data);

Invoked when the name is acquired.

Parameters

connection	The GDBusConnection on which to acquired the name.
name	The name being owned.
user_data	User data passed to `g_bus_own_name()` or `g_bus_own_name_on_connection()`.

Since 2.26

GBusNameLostCallback ()

void
(*GBusNameLostCallback) (GDBusConnection *connection,
                         const gchar *name,
                         gpointer user_data);

Invoked when the name is lost or connection has been closed.

Parameters

connection	The GDBusConnection on which to acquire the name or `NULL` if the connection was disconnected.
name	The name being owned.
user_data	User data passed to `g_bus_own_name()` or `g_bus_own_name_on_connection()`.

Since 2.26

g_bus_own_name ()

guint
g_bus_own_name (GBusType bus_type,
                const gchar *name,
                GBusNameOwnerFlags flags,
                GBusAcquiredCallback bus_acquired_handler,
                GBusNameAcquiredCallback name_acquired_handler,
                GBusNameLostCallback name_lost_handler,
                gpointer user_data,
                GDestroyNotify user_data_free_func);

Starts acquiring name on the bus specified by bus_type and calls name_acquired_handler and name_lost_handler when the name is acquired respectively lost. Callbacks will be invoked in the thread-default main context of the thread you are calling this function from.

You are guaranteed that one of the name_acquired_handler and name_lost_handler callbacks will be invoked after calling this function - there are three possible cases:

name_lost_handler with a NULL connection (if a connection to the bus can't be made).
bus_acquired_handler then name_lost_handler (if the name can't be obtained)
bus_acquired_handler then name_acquired_handler (if the name was obtained).

When you are done owning the name, just call g_bus_unown_name() with the owner id this function returns.

If the name is acquired or lost (for example another application could acquire the name if you allow replacement or the application currently owning the name exits), the handlers are also invoked. If the GDBusConnection that is used for attempting to own the name closes, then name_lost_handler is invoked since it is no longer possible for other processes to access the process.

You cannot use g_bus_own_name() several times for the same name (unless interleaved with calls to g_bus_unown_name()) - only the first call will work.

Another guarantee is that invocations of name_acquired_handler and name_lost_handler are guaranteed to alternate; that is, if name_acquired_handler is invoked then you are guaranteed that the next time one of the handlers is invoked, it will be name_lost_handler . The reverse is also true.

If you plan on exporting objects (using e.g. g_dbus_connection_register_object()), note that it is generally too late to export the objects in name_acquired_handler . Instead, you can do this in bus_acquired_handler since you are guaranteed that this will run before name is requested from the bus.

This behavior makes it very simple to write applications that wants to own names and export objects. Simply register objects to be exported in bus_acquired_handler and unregister the objects (if any) in name_lost_handler .

Parameters

bus_type	the type of bus to own a name on
name	the well-known name to own
flags	a set of flags from the GBusNameOwnerFlags enumeration
bus_acquired_handler	handler to invoke when connected to the bus of type `bus_type` or `NULL`.	[allow-none]
name_acquired_handler	handler to invoke when `name` is acquired or `NULL`.	[allow-none]
name_lost_handler	handler to invoke when `name` is lost or `NULL`.	[allow-none]
user_data	user data to pass to handlers
user_data_free_func	function for freeing `user_data` or `NULL`.	[allow-none]

Returns

an identifier (never 0) that an be used with g_bus_unown_name() to stop owning the name.

Since 2.26

g_bus_own_name_on_connection ()

guint
g_bus_own_name_on_connection (GDBusConnection *connection,
                              const gchar *name,
                              GBusNameOwnerFlags flags,
                              GBusNameAcquiredCallback name_acquired_handler,
                              GBusNameLostCallback name_lost_handler,
                              gpointer user_data,
                              GDestroyNotify user_data_free_func);

Like g_bus_own_name() but takes a GDBusConnection instead of a GBusType.

Parameters

connection	a GDBusConnection
name	the well-known name to own
flags	a set of flags from the GBusNameOwnerFlags enumeration
name_acquired_handler	handler to invoke when `name` is acquired or `NULL`.	[allow-none]
name_lost_handler	handler to invoke when `name` is lost or `NULL`.	[allow-none]
user_data	user data to pass to handlers
user_data_free_func	function for freeing `user_data` or `NULL`.	[allow-none]

Returns

an identifier (never 0) that an be used with g_bus_unown_name() to stop owning the name

Since 2.26

g_bus_unown_name ()

void
g_bus_unown_name (guint owner_id);

Stops owning a name.

Parameters

owner_id

an identifier obtained from g_bus_own_name()

Since 2.26

g_bus_own_name_with_closures ()

guint
g_bus_own_name_with_closures (GBusType bus_type,
                              const gchar *name,
                              GBusNameOwnerFlags flags,
                              GClosure *bus_acquired_closure,
                              GClosure *name_acquired_closure,
                              GClosure *name_lost_closure);

Version of g_bus_own_name() using closures instead of callbacks for easier binding in other languages.

Parameters

bus_type	the type of bus to own a name on
name	the well-known name to own
flags	a set of flags from the GBusNameOwnerFlags enumeration
bus_acquired_closure	GClosure to invoke when connected to the bus of type `bus_type` or `NULL`.	[allow-none]
name_acquired_closure	GClosure to invoke when `name` is acquired or `NULL`.	[allow-none]
name_lost_closure	GClosure to invoke when `name` is lost or `NULL`.	[allow-none]

Returns

an identifier (never 0) that an be used with g_bus_unown_name() to stop owning the name.

Since 2.26

g_bus_own_name_on_connection_with_closures ()

guint
g_bus_own_name_on_connection_with_closures
                               (GDBusConnection *connection,
                                const gchar *name,
                                GBusNameOwnerFlags flags,
                                GClosure *name_acquired_closure,
                                GClosure *name_lost_closure);

Version of g_bus_own_name_on_connection() using closures instead of callbacks for easier binding in other languages.

Parameters

connection	a GDBusConnection
name	the well-known name to own
flags	a set of flags from the GBusNameOwnerFlags enumeration
name_acquired_closure	GClosure to invoke when `name` is acquired or `NULL`.	[allow-none]
name_lost_closure	GClosure to invoke when `name` is lost or `NULL`.	[allow-none]

Returns

an identifier (never 0) that an be used with g_bus_unown_name() to stop owning the name.

Since 2.26

Types and Values

enum GBusNameOwnerFlags

Flags used in g_bus_own_name().

Members

G_BUS_NAME_OWNER_FLAGS_NONE	No flags set.
G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT	Allow another message bus connection to claim the name.
G_BUS_NAME_OWNER_FLAGS_REPLACE	If another message bus connection owns the name and have specified G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT, then take the name from the other connection.

Since 2.26