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874 lines
33 KiB
XML
874 lines
33 KiB
XML
<refentry id="gdbus-codegen" lang="en">
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<refentryinfo>
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<title>gdbus</title>
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<productname>GIO</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>David</firstname>
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<surname>Zeuthen</surname>
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<email>zeuthen@gmail.com</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>gdbus-codegen</refentrytitle>
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<manvolnum>1</manvolnum>
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<refmiscinfo class="manual">User Commands</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>gdbus-codegen</refname>
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<refpurpose>D-Bus code and documentation generator</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>gdbus-codegen</command>
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<arg><option>-h</option>, <option>--help</option></arg>
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<arg><option>--interface-prefix</option> <replaceable>org.project.Prefix</replaceable></arg>
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<arg><option>--generate-c-code</option> <replaceable>OUTFILES</replaceable></arg>
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<arg><option>--c-namespace</option> <replaceable>YourProject</replaceable></arg>
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<arg><option>--c-generate-object-manager</option></arg>
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<arg><option>--generate-docbook</option> <replaceable>OUTFILES</replaceable></arg>
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<arg><option>--xml-files</option> <replaceable>FILE</replaceable></arg>
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<group choice="plain" rep="repeat">
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<arg>
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<option>--annotate</option>
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<replaceable>ELEMENT</replaceable>
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<replaceable>KEY</replaceable>
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<replaceable>VALUE</replaceable>
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</arg>
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</group>
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<arg choice="plain">FILE</arg>
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<arg>
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<arg choice="plain" rep="repeat">FILE</arg>
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</arg>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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<command>gdbus-codegen</command> is used to generate code and/or
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documentation for one or more D-Bus interfaces. The tool reads
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<ulink
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url="http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format">D-Bus
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Introspection XML</ulink> files and generates output files. The
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tool currently supports generating C code (via
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<option>--generate-c-code</option>) and Docbook XML (via
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<option>--generate-docbook</option>).
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</para>
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</refsect1>
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<refsect1>
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<title>Generating C code</title>
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<para>
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When generating C code, a
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#GInterface<!-- -->-derived type is generated for each D-Bus
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interface. Additionally, for every generated type,
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<type>FooBar</type>, two concrete instantiable types,
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<type>FooBarProxy</type> and <type>FooBarSkeleton</type>, implementing
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said interface are also generated. The former is derived from
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#GDBusProxy and intended for use on the client side
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while the latter is derived from the
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#GDBusInterfaceSkeleton type making it easy to export on a
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#GDBusConnection either directly or via a
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#GDBusObjectManagerServer instance.
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</para>
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<para>
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The name of each generated C type is derived from the D-Bus
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interface name stripped with the prefix given with
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<option>--interface-prefix</option> and with the dots removed and
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initial characters capitalized. For example, for the D-Bus
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interface <literal>com.acme.Coyote</literal> the name used is
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<literal>ComAcmeCoyote</literal>. For the D-Bus interface
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<literal>org.project.Bar.Frobnicator</literal> with
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<option>--interface-prefix</option>
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<literal>org.project.</literal>, the name used is
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<literal>BarFrobnicator</literal>.
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</para>
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<para>
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For methods, signals and properties, if not specified, the name
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defaults to the name of the method, signal or property.
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</para>
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<para>
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Two forms of the name are used - the CamelCase form and the
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lower-case form. The CamelCase form is used for the #GType and
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struct name, while lower-case form is used in function names. The
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lower-case form is calculated by converting from CamelCase to
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lower-case and inserting underscores at word boundaries (using
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certain heuristics).
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</para>
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<para>
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If the value given by the <literal>org.gtk.GDBus.C.Name</literal>
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annotation or the <option>--c-namespace</option> option contains
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an underscore (sometimes called <emphasis>Ugly_Case</emphasis>),
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then the camel-case name is derived by removing all underscores,
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and the lower-case name is derived by lower-casing the
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string. This is useful in some situations where abbreviations are
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used. For example, if the annotation is used on the interface
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<literal>net.MyCorp.MyApp.iSCSITarget</literal> with the value
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<literal>iSCSI_Target</literal> the CamelCase form is
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<literal>iSCSITarget</literal> while the lower-case form is
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<literal>iscsi_target</literal>. If the annotation is used on the
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method <literal>EjectTheiPod</literal> with the value
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<literal>Eject_The_iPod</literal>, the lower-case form is
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<literal>eject_the_ipod</literal>.
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</para>
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</refsect1>
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<refsect1>
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<title>Generating Docbook documentation</title>
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<para>
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Each generated Docbook XML file (see the
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<option>--generate-docbook</option> option for details) is a <ulink
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url="http://www.docbook.org/tdg/en/html/refentry.html"><literal>RefEntry</literal></ulink>
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article describing the D-Bus interface.
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</para>
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</refsect1>
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<refsect1>
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<title>Options</title>
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<para>
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The following options are supported:
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</para>
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<variablelist>
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<varlistentry>
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<term><option>-h</option>, <option>--help</option></term>
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<listitem>
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<para>
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Show help and exit.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--xml-files</option> <replaceable>FILE</replaceable></term>
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<listitem>
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<para>
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The D-Bus introspection XML file.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--interface-prefix</option> <replaceable>org.project.Prefix.</replaceable></term>
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<listitem>
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<para>
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A prefix to strip from all D-Bus interface names when
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calculating the typename for the C binding and the Docbook
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<ulink
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url="http://www.docbook.org/tdg/en/html/primary.html">sortas
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attribute</ulink>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--generate-docbook</option> <replaceable>OUTFILES</replaceable></term>
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<listitem>
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<para>
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Generate Docbook Documentation for each D-Bus interface and
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put it in <filename>OUTFILES-NAME.xml</filename> where
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<literal>NAME</literal> is a place-holder for the interface
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name, e.g. <literal>net.Corp.FooBar</literal> and so on.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--generate-c-code</option> <replaceable>OUTFILES</replaceable></term>
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<listitem>
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<para>
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Generate C code for all D-Bus interfaces and put it in
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<filename>OUTFILES.c</filename> and
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<filename>OUTFILES.h</filename>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--c-namespace</option> <replaceable>YourProject</replaceable></term>
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<listitem>
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<para>
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The namespace to use for generated C code. This is expected
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to be in <ulink
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url="http://en.wikipedia.org/wiki/CamelCase">CamelCase</ulink>
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or <emphasis>Ugly_Case</emphasis> (see above).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--c-generate-object-manager</option></term>
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<listitem>
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<para>
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If this option is passed, suitable #GDBusObject,
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#GDBusObjectProxy, #GDBusObjectSkeleton and
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#GDBusObjectManagerClient subclasses are generated.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--annotate</option> <replaceable>ELEMENT</replaceable> <replaceable>KEY</replaceable> <replaceable>VALUE</replaceable></term>
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<listitem>
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<para>
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Used to inject D-Bus annotations into the given XML
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files. It can be used with interfaces, methods, signals,
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properties and arguments in the following way:
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</para>
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<informalexample><programlisting><![CDATA[
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gdbus-codegen --c-namespace MyApp \
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--generate-c-code myapp-generated \
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--annotate "org.project.InterfaceName" \
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org.gtk.GDBus.C.Name MyFrobnicator \
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--annotate "org.project.InterfaceName:Property" \
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bar bat \
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--annotate "org.project.InterfaceName.Method()" \
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org.freedesktop.DBus.Deprecated true \
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--annotate "org.project.InterfaceName.Method()[arg_name]" \
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snake hiss \
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--annotate "org.project.InterfaceName::Signal" \
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cat meow \
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--annotate "org.project.InterfaceName::Signal[arg_name]" \
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dog wuff \
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myapp-dbus-interfaces.xml
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]]></programlisting></informalexample>
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<para>
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Any UTF-8 string can be used for <replaceable>KEY</replaceable> and <replaceable>VALUE</replaceable>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Supported D-Bus Annotations</title>
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<para>
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The following D-Bus annotations are supported by
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<command>gdbus-codegen</command>:
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</para>
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<variablelist>
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<varlistentry>
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<term><literal>org.freedesktop.DBus.Deprecated</literal></term>
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<listitem>
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<para>
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Can be used on any <literal><interface></literal>,
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<literal><method></literal>,
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<literal><signal></literal> and
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<literal><property></literal> element to specify that
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the element is deprecated if its value is
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<literal>true</literal>. Note that this annotation is
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defined in the <ulink
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url="http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format">D-Bus
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specification</ulink> and can only assume the values
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<literal>true</literal> and <literal>false</literal>. In
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particular, you cannot specify the version that the element
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was deprecated in nor any helpful deprecation message. Such
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information should be added to the element documentation
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instead.
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</para>
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<para>
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When generating C code, this annotation is used to add
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#G_GNUC_DEPRECATED to generated functions for the element.
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</para>
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<para>
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When generating Docbook XML, a deprecation warning will
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appear along the documentation for the element.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.Since</literal></term>
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<listitem>
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<para>
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Can be used on any <literal><interface></literal>,
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<literal><method></literal>,
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<literal><signal></literal> and
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<literal><property></literal> element to specify the
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version (any free-form string but compared using a
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version-aware sort function) the element appeared in.
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</para>
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<para>
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When generating C code, this field is used to ensure
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function pointer order for preserving ABI/API, see <xref
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linkend="gdbus-code-stability"/>.
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</para>
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<para>
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When generating Docbook XML, the value of this tag appears
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in the documentation.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.DocString</literal></term>
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<listitem>
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<para>
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A string with Docbook content for documentation. This annotation can
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be used on <literal><interface></literal>,
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<literal><method></literal>,
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<literal><signal></literal>,
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<literal><property></literal> and
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<literal><arg></literal> elements.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.DocString.Short</literal></term>
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<listitem>
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<para>
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A string with Docbook content for short/brief
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documentation. This annotation can only be used on
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<literal><interface></literal> elements.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.C.Name</literal></term>
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<listitem>
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<para>
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Can be used on any <literal><interface></literal>,
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<literal><method></literal>,
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<literal><signal></literal> and
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<literal><property></literal> element to specify the
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name to use when generating C code. The value is expected to
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be in <ulink
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url="http://en.wikipedia.org/wiki/CamelCase">CamelCase</ulink>
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or <emphasis>Ugly_Case</emphasis> (see above).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.C.ForceGVariant</literal></term>
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<listitem>
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<para>
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If set to a non-empty string, a #GVariant instance will
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be used instead of the natural C type. This annotation can
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be used on any <literal><arg></literal> and
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<literal><property></literal> element.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>org.gtk.GDBus.C.UnixFD</literal></term>
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<listitem>
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<para>
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If set to a non-empty string, the generated code will
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include parameters to exchange file descriptors using the
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#GUnixFDList type. This annotation can be used on
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<literal><method></literal> elements.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>
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As an easier alternative to using the
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<literal>org.gtk.GDBus.DocString</literal> annotation, note that
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parser used by <command>gdbus-codegen</command> parses XML
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comments in a way similar to <ulink
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url="http://www.gtk.org/gtk-doc/">gtk-doc</ulink>:
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<informalexample><programlisting><![CDATA[
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<!--
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net.Corp.Bar:
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@short_description: A short description
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A <emphasis>longer</emphasis> description.
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This is a new paragraph.
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-->
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<interface name="net.corp.Bar">
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<!--
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FooMethod:
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@greeting: The docs for greeting parameter.
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@response: The docs for response parameter.
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The docs for the actual method.
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-->
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<method name="FooMethod">
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<arg name="greeting" direction="in" type="s"/>
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<arg name="response" direction="out" type="s"/>
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</method>
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<!--
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BarSignal:
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@blah: The docs for blah parameter.
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@boo: The docs for boo parameter.
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@since: 2.30
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The docs for the actual signal.
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-->
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<signal name="BarSignal">
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<arg name="blah" type="s"/>
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<arg name="boo" type="s"/>
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</signal>
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<!-- BazProperty: The docs for the property. -->
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<property name="BazProperty" type="s" access="read"/>
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</interface>
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]]></programlisting></informalexample>
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</para>
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<para>
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Note that <literal><![CDATA[@since]]></literal> can be used in any inline
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documentation bit (e.g. for interfaces, methods, signals and
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properties) to set the <literal>org.gtk.GDBus.Since</literal>
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annotation. For the <literal>org.gtk.GDBus.DocString</literal>
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annotation (and inline comments), note that substrings of the form
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<literal><![CDATA[#net.Corp.Bar]]></literal>,
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<literal><![CDATA[net.Corp.Bar.FooMethod()]]></literal>,
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<literal><![CDATA[#net.Corp.Bar::BarSignal]]></literal> and
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<literal><![CDATA[#net.Corp.InlineDocs:BazProperty]]></literal> are all
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expanded to links to the respective interface, method, signal and
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property.
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Additionally, substrings starting with <literal>@</literal> and <literal>%</literal> characters are rendered as
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<ulink url="http://www.docbook.org/tdg/en/html/parameter.html">parameter</ulink> and
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<ulink url="http://www.docbook.org/tdg/en/html/constant.html">constant</ulink> respectively.
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</para>
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<para>
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If both XML comments and
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<literal>org.gtk.GDBus.DocString</literal> or
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<literal>org.gtk.GDBus.DocString.Short</literal> annotations are
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present, the latter wins.
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</para>
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</refsect1>
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|
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<refsect1>
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<title>Example</title>
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<para>
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Consider the following D-Bus Introspection XML.
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</para>
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<informalexample><programlisting><![CDATA[
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<node>
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<interface name="net.Corp.MyApp.Frobber">
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<method name="HelloWorld">
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<arg name="greeting" direction="in" type="s"/>
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<arg name="response" direction="out" type="s"/>
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</method>
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<signal name="Notification">
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<arg name="icon_blob" type="ay"/>
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<arg name="height" type="i"/>
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<arg name="messages" type="as"/>
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</signal>
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<property name="Verbose" type="b" access="readwrite"/>
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</interface>
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</node>
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]]></programlisting>
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</informalexample>
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<para>
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If <command>gdbus-codegen</command> is used on this file like this:
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</para>
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<informalexample><programlisting><![CDATA[
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gdbus-codegen --generate-c-code myapp-generated \
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--c-namespace MyApp \
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--interface-prefix net.corp.MyApp. \
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net.Corp.MyApp.Frobber.xml
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]]></programlisting></informalexample>
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<para>
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two files called
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<filename>myapp-generated.[ch]</filename> are
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generated. The files provide an abstract
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#GTypeInterface<!-- -->-derived type called
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<type>MyAppFrobber</type> as well as two instantiable types with
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the same name but suffixed with <type>Proxy</type> and
|
|
<type>Skeleton</type>. The generated file, roughly, contains the
|
|
following facilities:
|
|
</para>
|
|
<informalexample><programlisting><![CDATA[
|
|
/* 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);
|
|
]]></programlisting></informalexample>
|
|
<para>
|
|
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:
|
|
</para>
|
|
<informaltable>
|
|
<tgroup cols="3">
|
|
<thead>
|
|
<row>
|
|
<entry></entry>
|
|
<entry>Client</entry>
|
|
<entry>Server</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>Types</entry>
|
|
<entry>Use <type>MyAppFrobberProxy</type></entry>
|
|
<entry>Any type implementing the <type>MyAppFrobber</type> interface</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Methods</entry>
|
|
<entry>Use <function>m_a_f_hello_world()</function> to call.</entry>
|
|
<entry>Receive via the <function>handle_hello_world()</function> signal handler. Complete the call with <function>m_a_f_complete_hello_world()</function></entry>
|
|
</row>
|
|
<row>
|
|
<entry>Signals</entry>
|
|
<entry>Connect to the <function>::notification</function> GObject signal.</entry>
|
|
<entry>Use <function>m_a_f_emit_notification()</function> to emit signal.</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Properties (Reading)</entry>
|
|
<entry>Use <function>m_a_f_get_verbose()</function> or <parameter>:verbose</parameter>.</entry>
|
|
<entry>Implement #GObject<!-- -->'s <function>get_property()</function> vfunc.</entry>
|
|
</row>
|
|
<row>
|
|
<entry>Properties (writing)</entry>
|
|
<entry>Use <function>m_a_f_set_verbose()</function> or <parameter>:verbose</parameter>.</entry>
|
|
<entry>Implement #GObject<!-- -->'s <function>set_property()</function> vfunc.</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</informaltable>
|
|
|
|
<refsect2>
|
|
<title>Client-side usage</title>
|
|
<para>
|
|
You can use the generated proxy type with the generated
|
|
constructors:
|
|
</para>
|
|
<informalexample><programlisting><![CDATA[
|
|
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);
|
|
]]></programlisting></informalexample>
|
|
<para>
|
|
Instead of using the generic #GDBusProxy facilities, one can use
|
|
the generated methods such as
|
|
<function>my_app_frobber_call_hello_world()</function> to invoke
|
|
the <function>net.Corp.MyApp.Frobber.HelloWorld()</function>
|
|
D-Bus method, connect to the the
|
|
<function>::notification</function> GObject signal to receive
|
|
the <function>net.Corp.MyApp.Frobber::Notication</function>
|
|
D-Bus signal and get/set the
|
|
<parameter>net.Corp.MyApp.Frobber:Verbose</parameter> D-Bus
|
|
Property using either the GObject property
|
|
<parameter>:verbose</parameter> or the
|
|
<function>my_app_get_verbose()</function> and
|
|
<function>my_app_set_verbose()</function> methods. Use the
|
|
standard #GObject::notify signal to listen to property changes.
|
|
</para>
|
|
<para>
|
|
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
|
|
<ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties">org.freedesktop.DBus.Properties.Set</ulink> 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.
|
|
</para>
|
|
</refsect2>
|
|
|
|
<refsect2>
|
|
<title>Server-side usage</title>
|
|
<para>
|
|
The generated <type>MyAppFrobber</type> interface is designed so
|
|
it is easy to implement it in a #GObject
|
|
subclass. For example, to handle
|
|
<function>HelloWorld()</function> method invocations, set the
|
|
vfunc for <function>handle_hello_hello_world()</function> in the
|
|
<type>MyAppFrobberIface</type> structure. Similary, to handle
|
|
the <parameter>net.Corp.MyApp.Frobber:Verbose</parameter>
|
|
property override the <parameter>:verbose</parameter> #GObject
|
|
property from the subclass. To emit a signal, use
|
|
e.g. <function>my_app_emit_signal()</function> or
|
|
g_signal_emit_by_name().
|
|
</para>
|
|
<para>
|
|
Instead of subclassing, it is often easier to use the generated
|
|
<type>MyAppFrobberSkeleton</type> subclass. To handle incoming
|
|
method calls, use <function>g_signal_connect()</function> with
|
|
the <function>::handle-*</function> signals and instead of
|
|
overriding #GObject<!-- -->'s
|
|
<function>get_property()</function> and
|
|
<function>set_property()</function> 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).
|
|
</para>
|
|
<informalexample><programlisting><![CDATA[
|
|
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 */
|
|
}
|
|
]]></programlisting></informalexample>
|
|
<para>
|
|
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
|
|
<link linkend="g-main-context-push-thread-default">thread-default main loop</link>
|
|
of the thread where the skeleton object was
|
|
contructed) and will cause emissions of the <ulink
|
|
url="http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties">org.freedesktop.DBus.Properties::PropertiesChanged</ulink>
|
|
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.
|
|
</para>
|
|
</refsect2>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>C Type Mapping</title>
|
|
<para>
|
|
Scalar types
|
|
(type-strings
|
|
<link linkend="G-VARIANT-TYPE-BOOLEAN:CAPS">'b'</link>,
|
|
<link linkend="G-VARIANT-TYPE-BYTE:CAPS">'y'</link>,
|
|
<link linkend="G-VARIANT-TYPE-INT16:CAPS">'n'</link>,
|
|
<link linkend="G-VARIANT-TYPE-UINT16:CAPS">'q'</link>,
|
|
<link linkend="G-VARIANT-TYPE-INT32:CAPS">'i'</link>,
|
|
<link linkend="G-VARIANT-TYPE-UINT32:CAPS">'u'</link>,
|
|
<link linkend="G-VARIANT-TYPE-INT64:CAPS">'x'</link>,
|
|
<link linkend="G-VARIANT-TYPE-UINT64:CAPS">'t'</link> and
|
|
<link linkend="G-VARIANT-TYPE-DOUBLE:CAPS">'d'</link>)
|
|
),
|
|
strings (type-strings
|
|
<link linkend="G-VARIANT-TYPE-STRING:CAPS">'s'</link>,
|
|
<link linkend="G-VARIANT-TYPE-BYTESTRING:CAPS">'ay'</link>,
|
|
<link linkend="G-VARIANT-TYPE-OBJECT-PATH:CAPS">'o'</link> and
|
|
<link linkend="G-VARIANT-TYPE-SIGNATURE:CAPS">'g'</link>) and
|
|
arrays of string (type-strings
|
|
<link linkend="G-VARIANT-TYPE-STRING-ARRAY:CAPS">'as'</link>,
|
|
<link linkend="G-VARIANT-TYPE-OBJECT-PATH-ARRAY:CAPS">'ao'</link> and
|
|
<link linkend="G-VARIANT-TYPE-BYTESTRING-ARRAY:CAPS">'aay'</link>)
|
|
are mapped to the natural types,
|
|
e.g. #gboolean, #gdouble, #gint, <link linkend="gchararray">gchar*</link>,
|
|
<link linkend="GStrv">gchar**</link> and
|
|
so on. Everything else is mapped to the #GVariant
|
|
type.
|
|
</para>
|
|
<para>
|
|
This automatic mapping can be turned off by using the annotation
|
|
<literal>org.gtk.GDBus.C.ForceGVariant</literal> - 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 <link linkend="G-VARIANT-TYPE-BYTESTRING:CAPS">'ay'</link>)
|
|
for data that could have embedded NUL bytes.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1 id="gdbus-code-stability">
|
|
<title>Stability Guarantees</title>
|
|
<para>
|
|
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.
|
|
</para>
|
|
<para>
|
|
The ABI of the generated #GType<!-- -->s will be preserved only if
|
|
the <literal>org.gtk.GDBus.Since</literal> 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 <literal>org.gtk.GDBus.Since</literal> annotation using
|
|
a greater version number than previous versions.
|
|
</para>
|
|
<para>
|
|
The generated C code currently happens to be annotated with <ulink
|
|
url="http://www.gtk.org/gtk-doc/">gtk-doc</ulink> / <ulink
|
|
url="https://live.gnome.org/GObjectIntrospection">GObject
|
|
Introspection</ulink> comments / annotations. The layout and
|
|
contents might change in the future so no guarantees about
|
|
e.g. <literal>SECTION</literal> usage etc. is given.
|
|
</para>
|
|
<para>
|
|
While the generated Docbook for D-Bus interfaces isn't expected to
|
|
change, no guarantees are given at this point.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Bugs</title>
|
|
<para>
|
|
Please send bug reports to either the distribution bug tracker
|
|
or the upstream bug tracker at
|
|
<ulink url="https://bugzilla.gnome.org/enter_bug.cgi?product=glib">https://bugzilla.gnome.org/enter_bug.cgi?product=glib</ulink>.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See also</title>
|
|
<para>
|
|
<citerefentry>
|
|
<refentrytitle>gdbus</refentrytitle><manvolnum>1</manvolnum>
|
|
</citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|