['sd_bus_set_connected_signal', '3', ['sd_bus_get_connected_signal'], ''],
['sd_bus_set_sender', '3', ['sd_bus_get_sender'], ''],
['sd_bus_set_watch_bind', '3', ['sd_bus_get_watch_bind'], ''],
+ ['sd_bus_slot_set_floating', '3', ['sd_bus_slot_get_floating'], ''],
['sd_bus_track_add_name',
'3',
['sd_bus_track_add_sender',
at a later time with
<citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>. If specified
as <constant>NULL</constant> the lifetime of the match is bound to the lifetime of the bus object itself, and the
- match cannot be removed independently.</para>
+ match is generally not removed independently. See
+ <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ details.</para>
<para>The message <parameter>m</parameter> passed to the callback is only borrowed, that is, the callback should
not call <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_set_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>sd_bus_set_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
<citerefentry><refentrytitle>sd_bus_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
to drop the reference.</para>
- <para>Queued but unwritten/unread messages also keep a reference
- to their bus connection object. For this reason, even if an
- application dropped all references to a bus connection, it might
- not get destroyed right away. Until all incoming queued
- messages are read, and until all outgoing unwritten messages are
- written, the bus object will stay
- alive. <function>sd_bus_flush()</function> may be used to write
- all outgoing queued messages so they drop their references. To
- flush the unread incoming messages, use
- <function>sd_bus_close()</function>, which will also close the bus
- connection. When using the default bus logic, it is a good idea to
- first invoke <function>sd_bus_flush()</function> followed by
- <function>sd_bus_close()</function> when a thread or process
- terminates, and thus its bus connection object should be
- freed.</para>
+ <para>Queued but unwritten/unread messages keep a reference to their bus connection object. For this reason, even
+ if an application dropped all references to a bus connection, it might not get destroyed right away. Until all
+ incoming queued messages are read, and until all outgoing unwritten messages are written, the bus object will stay
+ alive. <function>sd_bus_flush()</function> may be used to write all outgoing queued messages so they drop their
+ references. To flush the unread incoming messages, use <function>sd_bus_close()</function>, which will also close
+ the bus connection. When using the default bus logic, it is a good idea to first invoke
+ <function>sd_bus_flush()</function> followed by <function>sd_bus_close()</function> when a thread or process
+ terminates, and thus its bus connection object should be freed.</para>
+
+ <para>Normally, slot objects (as created by
+ <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry> and similar
+ calls) keep a reference to their bus connection object, too. Thus, as long as a bus slot object remains referenced
+ its bus object will remain allocated too. Optionally, bus slot objects may be placed in "floating" mode. When in
+ floating mode the life cycle of the bus slot object is bound to the bus object, i.e. when the bus object is freed
+ the bus slot object is automatically unreferenced too. The floating state of a slot object may be controlled
+ explicitly with
+ <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ though usually floating bus slot objects are created by passing <constant>NULL</constant> as the
+ <parameter>slot</parameter> parameter of <function>sd_bus_add_match()</function> and related calls, thus indicating
+ that the caller is not directly interested in referencing and managing the bus slot object.</para>
<para>The life cycle of the default bus connection should be the
responsibility of the code that creates/owns the thread the
--- /dev/null
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
+
+<refentry id="sd_bus_slot_set_floating">
+
+ <refentryinfo>
+ <title>sd_bus_slot_set_floating</title>
+ <productname>elogind</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>sd_bus_slot_set_floating</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_bus_slot_set_floating</refname>
+ <refname>sd_bus_slot_get_floating</refname>
+
+ <refpurpose>Control whether a bus slot object is "floating".</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <elogind/sd-bus.h></funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_slot_set_floating</function></funcdef>
+ <paramdef>sd_bus_slot *<parameter>bus</parameter></paramdef>
+ <paramdef>int <parameter>b</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_slot_get_floating</function></funcdef>
+ <paramdef>sd_bus_slot *<parameter>slot</parameter></paramdef>
+ </funcprototype>
+
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>sd_bus_slot_set_floating()</function> controls whether the specified bus slot object
+ <parameter>slot</parameter> shall be "floating" or not. A floating bus slot object's lifetime is bound to the
+ lifetime of the bus object it is associated with, meaning that it remains allocated as long as the bus object
+ itself and is freed automatically when the bus object is freed. Regular (i.e. non-floating) bus slot objects keep
+ the bus referenced, hence the bus object remains allocated at least as long as there remains at least one
+ referenced bus slot object around. The floating state hence controls the direction of referencing between the bus
+ object and the bus slot objects: if floating the bus pins the the bus slot, and otherwise the bus slot pins the bus
+ objects. Use <function>sd_bus_slot_set_floating()</function> to switch between both modes: if the
+ <parameter>b</parameter> parameter is zero, the slot object is considered floating, otherwise it is made a regular
+ (non-floating) slot object.</para>
+
+ <para>Bus slot objects may be allocated with calls such as
+ <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>. If the
+ <parameter>slot</parameter> of these functions is non-<constant>NULL</constant> the slot object will be of the
+ regular kind (i.e. non-floating), otherwise it will be created floating. With
+ <function>sd_bus_slot_set_floating()</function> a bus slot object allocated as regular can be converted into a
+ floating object and back. This is particularly useful for creating a bus slot object, then changing parameters of
+ it, and then turning it into a floating object, whose lifecycle is managed by the bus object.</para>
+
+ <para><function>sd_bus_slot_get_floating()</function> returns the current floating state of the specified bus slot
+ object. It returns negative on error, zero if the bus slot object is a regular (non-floating) object and positive
+ otherwise.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style
+ error code.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>-ECHILD</constant></term>
+
+ <listitem><para>The bus connection has been created in a different process.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ESTALE</constant></term>
+
+ <listitem><para>The bus object the specified bus slot object is associated with has already been freed, and
+ hence no change in the floating state can be made anymore.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
+
+ <para><function>sd_bus_slot_set_floating()</function> and <function>sd_bus_slot_get_floating()</function> are
+ available as a shared library, which can be compiled and linked to with the
+ <constant>libelogind</constant> <citerefentry
+ project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <para>
+ <citerefentry><refentrytitle>elogind</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>
~ianmdlvl / elogind.git / commitdiff