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GDBUS-CODEGEN(1)			  User Commands 			 GDBUS-CODEGEN(1)

NAME
       gdbus-codegen - D-Bus code and documentation generator

SYNOPSIS
       gdbus-codegen [-h, --help] [--interface-prefix org.project.Prefix]
		     [--generate-c-code OUTFILES] [--c-namespace YourProject]
		     [--c-generate-object-manager] [--generate-docbook OUTFILES]
		     [--xml-files FILE] [--annotate ELEMENT KEY VALUE]...  FILE [FILE...]

DESCRIPTION
       gdbus-codegen is used to generate code and/or documentation for one or more D-Bus
       interfaces. The tool reads D-Bus Introspection XML[1] files and generates output files.
       The tool currently supports generating C code (via --generate-c-code) and Docbook XML (via
       --generate-docbook).

GENERATING C CODE
       When generating C code, a #GInterface -derived type is generated for each D-Bus interface.
       Additionally, for every generated type, FooBar, two concrete instantiable types,
       FooBarProxy and FooBarSkeleton, implementing said interface are also generated. The former
       is derived from #GDBusProxy and intended for use on the client side while the latter is
       derived from the #GDBusInterfaceSkeleton type making it easy to export on a
       #GDBusConnection either directly or via a #GDBusObjectManagerServer instance.

       The name of each generated C type is derived from the D-Bus interface name stripped with
       the prefix given with --interface-prefix and with the dots removed and initial characters
       capitalized. For example, for the D-Bus interface com.acme.Coyote the name used is
       ComAcmeCoyote. For the D-Bus interface org.project.Bar.Frobnicator with
       --interface-prefixorg.project., the name used is BarFrobnicator.

       For methods, signals and properties, if not specified, the name defaults to the name of
       the method, signal or property.

       Two forms of the name are used - the CamelCase form and the lower-case form. The CamelCase
       form is used for the #GType and struct name, while lower-case form is used in function
       names. The lower-case form is calculated by converting from CamelCase to lower-case and
       inserting underscores at word boundaries (using certain heuristics).

       If the value given by the org.gtk.GDBus.C.Name annotation or the --c-namespace option
       contains an underscore (sometimes called Ugly_Case), then the camel-case name is derived
       by removing all underscores, and the lower-case name is derived by lower-casing the
       string. This is useful in some situations where abbreviations are used. For example, if
       the annotation is used on the interface net.MyCorp.MyApp.iSCSITarget with the value
       iSCSI_Target the CamelCase form is iSCSITarget while the lower-case form is iscsi_target.
       If the annotation is used on the method EjectTheiPod with the value Eject_The_iPod, the
       lower-case form is eject_the_ipod.

GENERATING DOCBOOK DOCUMENTATION
       Each generated Docbook XML file (see the --generate-docbook option for details) is a
       RefEntry[2] article describing the D-Bus interface.

OPTIONS
       The following options are supported:

       -h, --help
	   Show help and exit.

       --xml-files FILE
	   The D-Bus introspection XML file.

       --interface-prefix org.project.Prefix.
	   A prefix to strip from all D-Bus interface names when calculating the typename for the
	   C binding and the Docbook sortas attribute[3].

       --generate-docbook OUTFILES
	   Generate Docbook Documentation for each D-Bus interface and put it in
	   OUTFILES-NAME.xml where NAME is a place-holder for the interface name, e.g.
	   net.Corp.FooBar and so on.

       --generate-c-code OUTFILES
	   Generate C code for all D-Bus interfaces and put it in OUTFILES.c and OUTFILES.h.

       --c-namespace YourProject
	   The namespace to use for generated C code. This is expected to be in CamelCase[4] or
	   Ugly_Case (see above).

       --c-generate-object-manager
	   If this option is passed, suitable #GDBusObject, #GDBusObjectProxy,
	   #GDBusObjectSkeleton and #GDBusObjectManagerClient subclasses are generated.

       --annotate ELEMENT KEY VALUE
	   Used to inject D-Bus annotations into the given XML files. It can be used with
	   interfaces, methods, signals, properties and arguments in the following way:

	       gdbus-codegen --c-namespace MyApp			   \
		 --generate-c-code myapp-generated			   \
		 --annotate "org.project.InterfaceName" 		   \
		   org.gtk.GDBus.C.Name MyFrobnicator			   \
		 --annotate "org.project.InterfaceName:Property"	   \
		   bar bat						   \
		 --annotate "org.project.InterfaceName.Method()"	   \
		   org.freedesktop.DBus.Deprecated true 		   \
		 --annotate "org.project.InterfaceName.Method()[arg_name]" \
		   snake hiss						   \
		 --annotate "org.project.InterfaceName::Signal" 	   \
		   cat meow						   \
		 --annotate "org.project.InterfaceName::Signal[arg_name]"  \
		   dog wuff						   \
		 myapp-dbus-interfaces.xml
	   Any UTF-8 string can be used for KEY and VALUE.

SUPPORTED D-BUS ANNOTATIONS
       The following D-Bus annotations are supported by gdbus-codegen:

       org.freedesktop.DBus.Deprecated
	   Can be used on any <interface>, <method>, <signal> and <property> element to specify
	   that the element is deprecated if its value is true. Note that this annotation is
	   defined in the D-Bus specification[1] and can only assume the values true and false.
	   In particular, you cannot specify the version that the element was deprecated in nor
	   any helpful deprecation message. Such information should be added to the element
	   documentation instead.

	   When generating C code, this annotation is used to add #G_GNUC_DEPRECATED to generated
	   functions for the element.

	   When generating Docbook XML, a deprecation warning will appear along the documentation
	   for the element.

       org.gtk.GDBus.Since
	   Can be used on any <interface>, <method>, <signal> and <property> element to specify
	   the version (any free-form string but compared using a version-aware sort function)
	   the element appeared in.

	   When generating C code, this field is used to ensure function pointer order for
	   preserving ABI/API, see the section called "STABILITY GUARANTEES".

	   When generating Docbook XML, the value of this tag appears in the documentation.

       org.gtk.GDBus.DocString
	   A string with Docbook content for documentation. This annotation can be used on
	   <interface>, <method>, <signal>, <property> and <arg> elements.

       org.gtk.GDBus.DocString.Short
	   A string with Docbook content for short/brief documentation. This annotation can only
	   be used on <interface> elements.

       org.gtk.GDBus.C.Name
	   Can be used on any <interface>, <method>, <signal> and <property> element to specify
	   the name to use when generating C code. The value is expected to be in CamelCase[4] or
	   Ugly_Case (see above).

       org.gtk.GDBus.C.ForceGVariant
	   If set to a non-empty string, a #GVariant instance will be used instead of the natural
	   C type. This annotation can be used on any <arg> and <property> element.

       org.gtk.GDBus.C.UnixFD
	   If set to a non-empty string, the generated code will include parameters to exchange
	   file descriptors using the #GUnixFDList type. This annotation can be used on <method>
	   elements.

       As an easier alternative to using the org.gtk.GDBus.DocString annotation, note that parser
       used by gdbus-codegen parses XML comments in a way similar to gtk-doc[5]:

       Note that @since can be used in any inline documentation bit (e.g. for interfaces,
       methods, signals and properties) to set the org.gtk.GDBus.Since annotation. For the
       org.gtk.GDBus.DocString annotation (and inline comments), note that substrings of the form
       #net.Corp.Bar, net.Corp.Bar.FooMethod(), #net.Corp.Bar::BarSignal and
       #net.Corp.InlineDocs:BazProperty are all expanded to links to the respective interface,
       method, signal and property. Additionally, substrings starting with @ and % characters are
       rendered as parameter[6] and constant[7] respectively.

       If both XML comments and org.gtk.GDBus.DocString or org.gtk.GDBus.DocString.Short
       annotations are present, the latter wins.

EXAMPLE
       Consider the following D-Bus Introspection XML.

	   <node>
	     <interface name="net.Corp.MyApp.Frobber">
	       <method name="HelloWorld">
		 <arg name="greeting" direction="in" type="s"/>
		 <arg name="response" direction="out" type="s"/>
	       </method>

	       <signal name="Notification">
		 <arg name="icon_blob" type="ay"/>
		 <arg name="height" type="i"/>
		 <arg name="messages" type="as"/>
	       </signal>

	       <property name="Verbose" type="b" access="readwrite"/>
	     </interface>
	   </node>

       If gdbus-codegen is used on this file like this:

	   gdbus-codegen --generate-c-code myapp-generated	 \
			 --c-namespace MyApp			 \
			 --interface-prefix net.corp.MyApp.	 \
			 net.Corp.MyApp.Frobber.xml

       two files called myapp-generated.[ch] are generated. The files provide an abstract
       #GTypeInterface -derived type called MyAppFrobber as well as two instantiable types with
       the same name but suffixed with Proxy and Skeleton. The generated file, roughly, contains
       the following facilities:

	   /* GType macros for the three generated types */
	   #define MY_APP_TYPE_FROBBER (my_app_frobber_get_type ())
	   #define MY_APP_TYPE_FROBBER_SKELETON (my_app_frobber_skeleton_get_type ())
	   #define MY_APP_TYPE_FROBBER_PROXY (my_app_frobber_proxy_get_type ())

	   typedef struct _MyAppFrobber MyAppFrobber; /* Dummy typedef */

	   typedef struct
	   {
	     GTypeInterface parent_iface;

	     /* Signal handler for the ::notification signal */
	     void (*notification) (MyAppFrobber *proxy,
				   GVariant *icon_blob,
				   gint height,
				   const gchar* const *messages);

	     /* Signal handler for the ::handle-hello-world signal */
	     gboolean (*handle_hello_world) (MyAppFrobber *proxy,
					     GDBusMethodInvocation *invocation,
					     const gchar *greeting);
	   } MyAppFrobberIface;

	   /* Asynchronously calls HelloWorld() */
	   void
	   my_app_frobber_call_hello_world (MyAppFrobber *proxy,
					    const gchar *greeting,
					    GCancellable *cancellable,
					    GAsyncReadyCallback callback,
					    gpointer user_data);
	   gboolean
	   my_app_frobber_call_hello_world_finish (MyAppFrobber *proxy,
						   gchar **out_response,
						   GAsyncResult *res,
						   GError **error);

	   /* Synchronously calls HelloWorld(). Blocks calling thread. */
	   gboolean
	   my_app_frobber_call_hello_world_sync (MyAppFrobber *proxy,
						 const gchar *greeting,
						 gchar **out_response,
						 GCancellable *cancellable,
						 GError **error);

	   /* Completes handling the HelloWorld() method call */
	   void
	   my_app_frobber_complete_hello_world (MyAppFrobber *object,
						GDBusMethodInvocation *invocation,
						const gchar *response);

	   /* Emits the ::notification signal / Notification() D-Bus signal */
	   void
	   my_app_frobber_emit_notification (MyAppFrobber *object,
					     GVariant *icon_blob,
					     gint height,
					     const gchar* const *messages);

	   /* Gets the :verbose GObject property / Verbose D-Bus property.
	    * Does no blocking I/O.
	    */
	   gboolean my_app_frobber_get_verbose (MyAppFrobber *object);

	   /* Sets the :verbose GObject property / Verbose D-Bus property.
	    * Does no blocking I/O.
	    */
	   void my_app_frobber_set_verbose (MyAppFrobber *object,
					    gboolean	  value);

	   /* Gets the interface info */
	   GDBusInterfaceInfo *my_app_frobber_interface_info (void);

	   /* Creates a new skeleton object, ready to be exported */
	   MyAppFrobber *my_app_frobber_skeleton_new (void);

	   /* Client-side proxy constructors.
	    *
	    * Additionally, _new_for_bus(), _new_for_bus_finish() and
	    * _new_for_bus_sync() proxy constructors are also generated.
	    */
	   void
	   my_app_frobber_proxy_new	   (GDBusConnection	*connection,
					    GDBusProxyFlags	 flags,
					    const gchar 	*name,
					    const gchar 	*object_path,
					    GCancellable	*cancellable,
					    GAsyncReadyCallback  callback,
					    gpointer		 user_data);
	   MyAppFrobber *
	   my_app_frobber_proxy_new_finish (GAsyncResult	*res,
					    GError	       **error);
	   MyAppFrobber *
	   my_app_frobber_proxy_new_sync   (GDBusConnection	*connection,
					    GDBusProxyFlags	 flags,
					    const gchar 	*name,
					    const gchar 	*object_path,
					    GCancellable	*cancellable,
					    GError	       **error);

       Thus, for every D-Bus method, there will be three C functions for calling the method, one
       #GObject signal for handling an incoming call and one C function for completing an
       incoming call. For every D-Bus signal, there's one #GObject signal and one C function for
       emitting it. For every D-Bus property, two C functions are generated (one setter, one
       getter) and one #GObject property. The following table summarizes the generated facilities
       and where they are applicable:

       +---------------------+-------------------------+------------------------------+
       |		     | Client		       | Server 		      |
       +---------------------+-------------------------+------------------------------+
       |Types		     | Use MyAppFrobberProxy   | Any type implementing	      |
       |		     |			       | the MyAppFrobber	      |
       |		     |			       | interface		      |
       +---------------------+-------------------------+------------------------------+
       |Methods 	     | Use m_a_f_hello_world() | Receive via the	      |
       |		     | to call. 	       | handle_hello_world()	      |
       |		     |			       | signal handler. Complete     |
       |		     |			       | the call with		      |
       |		     |			       | m_a_f_complete_hello_world() |
       +---------------------+-------------------------+------------------------------+
       |Signals 	     | Connect to the	       | Use			      |
       |		     | ::notification GObject  | m_a_f_emit_notification() to |
       |		     | signal.		       | emit signal.		      |
       +---------------------+-------------------------+------------------------------+
       |Properties (Reading) | Use m_a_f_get_verbose() | Implement #GObject's	      |
       |		     | or :verbose.	       | get_property() vfunc.	      |
       +---------------------+-------------------------+------------------------------+
       |Properties (writing) | Use m_a_f_set_verbose() | Implement #GObject's	      |
       |		     | or :verbose.	       | set_property() vfunc.	      |
       +---------------------+-------------------------+------------------------------+

   Client-side usage
       You can use the generated proxy type with the generated constructors:

	       MyAppFrobber *proxy;
	       GError *error;

	       error = NULL;
	       proxy = my_app_frobber_proxy_new_for_bus_sync (
			   G_BUS_TYPE_SESSION,
			   G_DBUS_PROXY_FLAGS_NONE,
			   "net.Corp.MyApp",		  /* bus name */
			   "/net/Corp/MyApp/SomeFrobber", /* object */
			   NULL,			  /* GCancellable* */
			   &error);
	       /* do stuff with proxy */
	       g_object_unref (proxy);

       Instead of using the generic #GDBusProxy facilities, one can use the generated methods
       such as my_app_frobber_call_hello_world() to invoke the
       net.Corp.MyApp.Frobber.HelloWorld() D-Bus method, connect to the the ::notification
       GObject signal to receive the net.Corp.MyApp.Frobber::Notication D-Bus signal and get/set
       the net.Corp.MyApp.Frobber:Verbose D-Bus Property using either the GObject property
       :verbose or the my_app_get_verbose() and my_app_set_verbose() methods. Use the standard
       #GObject::notify signal to listen to property changes.

       Note that all property access is via #GDBusProxy 's property cache so no I/O is ever done
       when reading properties. Also note that setting a property will cause the
       org.freedesktop.DBus.Properties.Set[8] method to be called on the remote object. This
       call, however, is asynchronous so setting a property won't block. Further, the change is
       delayed and no error checking is possible.

   Server-side usage
       The generated MyAppFrobber interface is designed so it is easy to implement it in a
       #GObject subclass. For example, to handle HelloWorld() method invocations, set the vfunc
       for handle_hello_hello_world() in the MyAppFrobberIface structure. Similary, to handle the
       net.Corp.MyApp.Frobber:Verbose property override the :verbose #GObject property from the
       subclass. To emit a signal, use e.g.  my_app_emit_signal() or g_signal_emit_by_name().

       Instead of subclassing, it is often easier to use the generated MyAppFrobberSkeleton
       subclass. To handle incoming method calls, use g_signal_connect() with the ::handle-*
       signals and instead of overriding #GObject 's get_property() and set_property() vfuncs,
       use g_object_get() and g_object_set() or the generated property getters and setters (the
       generated class has an internal property bag implementation).

	   static gboolean
	   on_handle_hello_world (MyAppFrobber		 *interface,
				  GDBusMethodInvocation  *invocation,
				  const gchar		 *greeting,
				  gpointer		  user_data)
	   {
	     if (g_strcmp0 (greeting, "Boo") != 0)
	       {
		 gchar *response;
		 response = g_strdup_printf ("Word! You said `%s'.", greeting);
		 my_app_complete_hello_world (interface, invocation, response);
		 g_free (response);
	       }
	     else
	       {
		 g_dbus_method_invocation_return_error (invocation,
			    MY_APP_ERROR,
			    MY_APP_ERROR_NO_WHINING,
			    "Hey, %s, there will be no whining!",
			    g_dbus_method_invocation_get_sender (invocation));
	       }
	     return TRUE;
	   }

	     [...]

	     interface = my_app_frobber_skeleton_new ();
	     my_app_frobber_set_verbose (interface, TRUE);

	     g_signal_connect (interface,
			       "handle-hello-world",
			       G_CALLBACK (on_handle_hello_world),
			       some_user_data);

	     [...]

	     error = NULL;
	     if (!g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (interface),
						    connection,
						    "/path/of/dbus_object",
						    &error))
	       {
		 /* handle error */
	       }

       To facilitate atomic changesets (multiple properties changing at the same time),
       #GObject::notify signals are queued up when received. The queue is drained in an idle
       handler (which is called from the thread-default main loop of the thread where the
       skeleton object was contructed) and will cause emissions of the
       org.freedesktop.DBus.Properties::PropertiesChanged[8] signal with all the properties that
       have changed. Use g_dbus_interface_skeleton_flush() or g_dbus_object_skeleton_flush() to
       empty the queue immediately. Use g_object_freeze_notify() and g_object_thaw_notify() for
       atomic changesets if on a different thread.

C TYPE MAPPING
       Scalar types (type-strings and and and gchar*, gchar** and so on. Everything else is
       mapped to the #GVariant type.

       This automatic mapping can be turned off by using the annotation
       org.gtk.GDBus.C.ForceGVariant - if used then a #GVariant is always exchanged instead of
       the corresponding native C type. This annotation may be convenient to use when using
       bytestrings (type-string

STABILITY GUARANTEES
       The generated C functions are guaranteed to not change their ABI that is, if a method,
       signal or property does not change its signature in the introspection XML, the generated C
       functions will not change its C ABI either.

       The ABI of the generated #GType s will be preserved only if the org.gtk.GDBus.Since
       annotation is used judiciously -- this is because the VTable for the #GInterface relies on
       functions pointers for signal handlers. Specifically, if a D-Bus method, property or
       signal or is added to a D-Bus interface, then ABI of the generated #GInterface type is
       preserved if, and only if, each added method, property signal is annotated with they
       org.gtk.GDBus.Since annotation using a greater version number than previous versions.

       The generated C code currently happens to be annotated with gtk-doc[5] / GObject
       Introspection[9] comments / annotations. The layout and contents might change in the
       future so no guarantees about e.g.  SECTION usage etc. is given.

       While the generated Docbook for D-Bus interfaces isn't expected to change, no guarantees
       are given at this point.

BUGS
       Please send bug reports to either the distribution bug tracker or the upstream bug tracker
       at https://bugzilla.gnome.org/enter_bug.cgi?product=glib.

SEE ALSO
       gdbus(1)

NOTES
	1. D-Bus Introspection XML
	   http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format

	2. RefEntry
	   http://www.docbook.org/tdg/en/html/refentry.html

	3. sortas attribute
	   http://www.docbook.org/tdg/en/html/primary.html

	4. CamelCase
	   http://en.wikipedia.org/wiki/CamelCase

	5. gtk-doc
	   http://www.gtk.org/gtk-doc/

	6. parameter
	   http://www.docbook.org/tdg/en/html/parameter.html

	7. constant
	   http://www.docbook.org/tdg/en/html/constant.html

	8. org.freedesktop.DBus.Properties.Set
	   http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties

	9. GObject Introspection
	   https://live.gnome.org/GObjectIntrospection

GIO										 GDBUS-CODEGEN(1)
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