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sd-bus: Wrap add_object_vtable docs at 100 columns
This commit is contained in:
Daan De Meyer
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commit
50b88e87c8
@ -188,40 +188,44 @@
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_add_object_vtable()</function> is used to declare attributes for the path object
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path <parameter>path</parameter> connected to the bus connection <parameter>bus</parameter> under the
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interface <parameter>interface</parameter>. The table <parameter>vtable</parameter> may contain property
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declarations using <constant>SD_BUS_PROPERTY()</constant> or
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<constant>SD_BUS_WRITABLE_PROPERTY()</constant>, method declarations using
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<constant>SD_BUS_METHOD()</constant>, <constant>SD_BUS_METHOD_WITH_NAMES()</constant>,
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<para><function>sd_bus_add_object_vtable()</function> is used to declare attributes for the path
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object path <parameter>path</parameter> connected to the bus connection
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<parameter>bus</parameter> under the interface <parameter>interface</parameter>. The table
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<parameter>vtable</parameter> may contain property declarations using
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<constant>SD_BUS_PROPERTY()</constant> or <constant>SD_BUS_WRITABLE_PROPERTY()</constant>,
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method declarations using <constant>SD_BUS_METHOD()</constant>,
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<constant>SD_BUS_METHOD_WITH_NAMES()</constant>,
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<constant>SD_BUS_METHOD_WITH_OFFSET()</constant>, or
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<constant>SD_BUS_METHOD_WITH_NAMES_OFFSET()</constant>, and signal declarations using
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<constant>SD_BUS_SIGNAL_WITH_NAMES()</constant> or <constant>SD_BUS_SIGNAL()</constant>, see below. The
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<replaceable>userdata</replaceable> parameter contains a pointer that will be passed to various callback
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functions. It may be specified as <constant>NULL</constant> if no value is necessary.</para>
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<constant>SD_BUS_SIGNAL_WITH_NAMES()</constant> or <constant>SD_BUS_SIGNAL()</constant>, see
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below. The <replaceable>userdata</replaceable> parameter contains a pointer that will be passed
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to various callback functions. It may be specified as <constant>NULL</constant> if no value is
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necessary.</para>
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<para><function>sd_bus_add_fallback_vtable()</function> is similar to
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<function>sd_bus_add_object_vtable()</function>, but is used to register "fallback" attributes. When
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looking for an attribute declaration, bus object paths registered with
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<function>sd_bus_add_object_vtable()</function> are checked first. If no match is found, the fallback
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vtables are checked for each prefix of the bus object path, i.e. with the last slash-separated components
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successively removed. This allows the vtable to be used for an arbitrary number of dynamically created
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objects.</para>
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<function>sd_bus_add_object_vtable()</function>, but is used to register "fallback" attributes.
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When looking for an attribute declaration, bus object paths registered with
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<function>sd_bus_add_object_vtable()</function> are checked first. If no match is found, the
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fallback vtables are checked for each prefix of the bus object path, i.e. with the last
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slash-separated components successively removed. This allows the vtable to be used for an
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arbitrary number of dynamically created objects.</para>
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<para>Parameter <replaceable>find</replaceable> is a function which is used to locate the target object
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based on the bus object path <replaceable>path</replaceable>. It must return <constant>1</constant> and
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set the <parameter>ret_found</parameter> output parameter if the object is found, return
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<constant>0</constant> if the object was not found, and return a negative errno-style error code or
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initialize the error structure <replaceable>ret_error</replaceable> on error. The pointer passed in
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<parameter>ret_found</parameter> will be used as the <parameter>userdata</parameter> parameter for the
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callback functions (offset by the <parameter>offset</parameter> offsets as specified in the vtable
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entries).</para>
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<para>Parameter <replaceable>find</replaceable> is a function which is used to locate the target
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object based on the bus object path <replaceable>path</replaceable>. It must return
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<constant>1</constant> and set the <parameter>ret_found</parameter> output parameter if the
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object is found, return <constant>0</constant> if the object was not found, and return a
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negative errno-style error code or initialize the error structure
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<replaceable>ret_error</replaceable> on error. The pointer passed in
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<parameter>ret_found</parameter> will be used as the <parameter>userdata</parameter> parameter
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for the callback functions (offset by the <parameter>offset</parameter> offsets as specified in
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the vtable entries).</para>
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<para>For both functions, a match slot is created internally. If the output parameter
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<replaceable>slot</replaceable> is <constant>NULL</constant>, a "floating" slot object is created, see
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<replaceable>slot</replaceable> is <constant>NULL</constant>, a "floating" slot object is
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created, see
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<citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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Otherwise, a pointer to the slot object is returned. In that case, the reference to the slot object
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should be dropped when the vtable is not needed anymore, see
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Otherwise, a pointer to the slot object is returned. In that case, the reference to the slot
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object should be dropped when the vtable is not needed anymore, see
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<citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para>
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@ -245,23 +249,25 @@
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<term><constant>SD_BUS_METHOD_WITH_OFFSET()</constant></term>
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<term><constant>SD_BUS_METHOD()</constant></term>
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<listitem><para>Declare a D-Bus method with the name <replaceable>member</replaceable>, parameter
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signature <replaceable>signature</replaceable>, result signature <replaceable>result</replaceable>.
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Parameters <replaceable>in_names</replaceable> and <replaceable>out_names</replaceable> specify the
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argument names of the input and output arguments in the function signature. The handler function
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<replaceable>handler</replaceable> must be of type <function>sd_bus_message_handler_t</function>.
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It will be called to handle the incoming messages that call this method. It receives a pointer that
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is the <replaceable>userdata</replaceable> parameter passed to the registration function offset by
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<replaceable>offset</replaceable> bytes. This may be used to pass pointers to different fields in
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the same data structure to different methods in the same
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vtable. <replaceable>in_names</replaceable> and <replaceable>out_names</replaceable> should be
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<listitem><para>Declare a D-Bus method with the name <replaceable>member</replaceable>,
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parameter signature <replaceable>signature</replaceable>, result signature
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<replaceable>result</replaceable>. Parameters <replaceable>in_names</replaceable> and
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<replaceable>out_names</replaceable> specify the argument names of the input and output
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arguments in the function signature. The handler function
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<replaceable>handler</replaceable> must be of type
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<function>sd_bus_message_handler_t</function>. It will be called to handle the incoming
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messages that call this method. It receives a pointer that is the
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<replaceable>userdata</replaceable> parameter passed to the registration function offset
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by <replaceable>offset</replaceable> bytes. This may be used to pass pointers to different
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fields in the same data structure to different methods in the same vtable.
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<replaceable>in_names</replaceable> and <replaceable>out_names</replaceable> should be
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created using the <constant>SD_BUS_PARAM()</constant> macro, see below. Parameter
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<replaceable>flags</replaceable> is a combination of flags, see below.</para>
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<para><constant>SD_BUS_METHOD_WITH_NAMES()</constant>,
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<constant>SD_BUS_METHOD_WITH_OFFSET()</constant>, and <constant>SD_BUS_METHOD()</constant> are
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variants which specify zero offset (<replaceable>userdata</replaceable> parameter is passed with
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no change), leave the names unset (i.e. no parameter names), or both.</para>
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<constant>SD_BUS_METHOD_WITH_OFFSET()</constant>, and <constant>SD_BUS_METHOD()</constant>
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are variants which specify zero offset (<replaceable>userdata</replaceable> parameter is
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passed with no change), leave the names unset (i.e. no parameter names), or both.</para>
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</listitem>
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</varlistentry>
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@ -285,29 +291,31 @@
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<term><constant>SD_BUS_WRITABLE_PROPERTY()</constant></term>
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<term><constant>SD_BUS_PROPERTY()</constant></term>
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<listitem><para>Declare a D-Bus property with the name <replaceable>member</replaceable> and value
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signature <replaceable>signature</replaceable>. Parameters <replaceable>get</replaceable> and
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<replaceable>set</replaceable> are the getter and setter methods. They are called with a pointer
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that is the <replaceable>userdata</replaceable> parameter passed to the registration function
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offset by <replaceable>offset</replaceable> bytes. This may be used pass pointers to different
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fields in the same data structure to different setters and getters in the same vtable. Parameter
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<replaceable>flags</replaceable> is a combination of flags, see below.</para>
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<listitem><para>Declare a D-Bus property with the name <replaceable>member</replaceable>
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and value signature <replaceable>signature</replaceable>. Parameters
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<replaceable>get</replaceable> and <replaceable>set</replaceable> are the getter and
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setter methods. They are called with a pointer that is the
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<replaceable>userdata</replaceable> parameter passed to the registration function offset
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by <replaceable>offset</replaceable> bytes. This may be used pass pointers to different
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fields in the same data structure to different setters and getters in the same vtable.
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Parameter <replaceable>flags</replaceable> is a combination of flags, see below.</para>
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<para>The setter and getter methods may be omitted (specified as <constant>NULL</constant>), if the
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property has one of the basic types or <literal>as</literal> in case of read-only properties. In
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those cases, the <replaceable>userdata</replaceable> and <replaceable>offset</replaceable>
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parameters must together point to valid variable of the corresponding type. A default setter and
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getters will be provided, which simply copy the argument between this variable and the message.
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<para>The setter and getter methods may be omitted (specified as
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<constant>NULL</constant>), if the property has one of the basic types or
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<literal>as</literal> in case of read-only properties. In those cases, the
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<replaceable>userdata</replaceable> and <replaceable>offset</replaceable> parameters must
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together point to valid variable of the corresponding type. A default setter and getters
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will be provided, which simply copy the argument between this variable and the message.
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</para>
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<para><constant>SD_BUS_PROPERTY()</constant> is used to define a read-only property.</para>
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</listitem>
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<para><constant>SD_BUS_PROPERTY()</constant> is used to define a read-only property.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>SD_BUS_PARAM()</constant></term>
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<listitem><para>Parameter names should be wrapped in this macro, see the example below.</para>
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</listitem>
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<listitem><para>Parameter names should be wrapped in this macro, see the example below.
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</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect2>
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@ -324,7 +332,7 @@
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<term><constant>SD_BUS_VTABLE_DEPRECATED</constant></term>
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<listitem><para>Mark this vtable entry as deprecated using the
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<constant>org.freedesktop.DBus.Deprecated</constant> annotation in introspection data. If
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<constant>org.freedesktop.DBus.Deprecated</constant> annotation in introspection data. If
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specified for <constant>SD_BUS_VTABLE_START()</constant>, the annotation is applied to the
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enclosing interface.</para></listitem>
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</varlistentry>
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@ -332,10 +340,9 @@
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<varlistentry>
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<term><constant>SD_BUS_VTABLE_HIDDEN</constant></term>
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<listitem><para>Make this vtable entry hidden. It will not be shown in introspection data. If
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specified for <constant>SD_BUS_VTABLE_START()</constant>, all entries in the array are hidden.
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</para>
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</listitem>
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<listitem><para>Make this vtable entry hidden. It will not be shown in introspection data.
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If specified for <constant>SD_BUS_VTABLE_START()</constant>, all entries in the array are
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hidden.</para></listitem>
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</varlistentry>
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<varlistentry>
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@ -343,8 +350,7 @@
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<listitem><para>Mark this vtable entry as unprivileged. If not specified, the
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<constant>org.freedesktop.systemd1.Privileged</constant> annotation with value
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<literal>true</literal> will be shown in introspection data.</para>
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</listitem>
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<literal>true</literal> will be shown in introspection data.</para></listitem>
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</varlistentry>
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<varlistentry>
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@ -361,27 +367,28 @@
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<term><constant>SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION</constant></term>
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<listitem><para>Those three flags correspond to different values of the
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<constant>org.freedesktop.DBus.Property.EmitsChangedSignal</constant> annotation, which specifies
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whether the <constant>org.freedesktop.DBus.Properties.PropertiesChanged</constant> signal is
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emitted whenever the property changes. <constant>SD_BUS_VTABLE_PROPERTY_CONST</constant> corresponds to
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<constant>const</constant> and means that the property never changes during the lifetime of the
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object it belongs to, so no signal needs to be emitted.
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<constant>SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE</constant> corresponds to <constant>true</constant> and means
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that the signal is emitted. <constant>SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION</constant> corresponds to
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<constant>invalidates</constant> and means that the signal is emitted, but the value is not included
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in the signal.</para>
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</listitem>
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<constant>org.freedesktop.DBus.Property.EmitsChangedSignal</constant> annotation, which
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specifies whether the
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<constant>org.freedesktop.DBus.Properties.PropertiesChanged</constant> signal is emitted
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whenever the property changes. <constant>SD_BUS_VTABLE_PROPERTY_CONST</constant>
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corresponds to <constant>const</constant> and means that the property never changes during
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the lifetime of the object it belongs to, so no signal needs to be emitted.
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<constant>SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE</constant> corresponds to
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<constant>true</constant> and means that the signal is emitted.
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<constant>SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION</constant> corresponds to
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<constant>invalidates</constant> and means that the signal is emitted, but the value is
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not included in the signal.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>SD_BUS_VTABLE_PROPERTY_EXPLICIT</constant></term>
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<listitem><para>Mark this vtable property entry as requiring explicit request to for the value to
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be shown (generally because the value is large or slow to calculate). This entry cannot be combined
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with <constant>SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE</constant>, and will not be shown in property listings by
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default (e.g. <command>busctl introspect</command>). This corresponds to the
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<constant>org.freedesktop.systemd1.Explicit</constant> annotation in introspection data.</para>
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</listitem>
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<listitem><para>Mark this vtable property entry as requiring explicit request to for the
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value to be shown (generally because the value is large or slow to calculate). This entry
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cannot be combined with <constant>SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE</constant>, and will
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not be shown in property listings by default (e.g. <command>busctl introspect</command>).
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This corresponds to the <constant>org.freedesktop.systemd1.Explicit</constant> annotation
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in introspection data.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect2>
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@ -395,9 +402,9 @@
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<programlisting><xi:include href="vtable-example.c" parse="text" /></programlisting>
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<para>This creates a simple client on the bus (the user bus, when run as normal user).
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We may use the D-Bus <constant>org.freedesktop.DBus.Introspectable.Introspect</constant>
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call to acquire the XML description of the interface:</para>
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<para>This creates a simple client on the bus (the user bus, when run as normal user). We may
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use the D-Bus <constant>org.freedesktop.DBus.Introspectable.Introspect</constant> call to
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acquire the XML description of the interface:</para>
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<programlisting><xi:include href="vtable-example.xml" parse="text" /></programlisting>
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</example>
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@ -407,8 +414,8 @@
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<title>Return Value</title>
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<para>On success, <function>sd_bus_add_object_vtable</function> and
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<function>sd_bus_add_fallback_vtable</function> calls return 0 or a positive integer. On failure, they
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return a negative errno-style error code.</para>
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<function>sd_bus_add_fallback_vtable</function> calls return 0 or a positive integer. On
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failure, they return a negative errno-style error code.</para>
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<refsect2>
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<title>Errors</title>
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@ -419,8 +426,9 @@
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>One of the required parameters is <constant>NULL</constant> or invalid. A reserved
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D-Bus interface was passed as the <replaceable>interface</replaceable> parameter.</para></listitem>
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<listitem><para>One of the required parameters is <constant>NULL</constant> or invalid. A
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reserved D-Bus interface was passed as the <replaceable>interface</replaceable> parameter.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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@ -445,8 +453,8 @@
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<term><constant>-EPROTOTYPE</constant></term>
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<listitem><para><function>sd_bus_add_object_vtable</function> and
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<function>sd_bus_add_fallback_vtable</function> have been both called
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for the same bus object path, which is not allowed.</para></listitem>
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<function>sd_bus_add_fallback_vtable</function> have been both called for the same bus
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object path, which is not allowed.</para></listitem>
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</varlistentry>
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<varlistentry>
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