systemd/man/sd_bus_set_close_on_exit.xml
Luca Boccassi bf876e3f3e sd-bus: store and compare per-module static origin id
sd-bus objects use hashmaps, which use module-global state, so it is not safe
to pass a sd-bus object created by a module instance to another module instance
(e.g.: when two libraries static linking sd-bus are pulled in a single process).
Initialize a random per-module origin id and store it in the object, and compare
it when entering a public API, and error out if they don't match, together with
the PID.
2023-04-25 12:24:25 +01:00

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XML

<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_bus_set_close_on_exit"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_set_close_on_exit</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_set_close_on_exit</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_set_close_on_exit</refname>
<refname>sd_bus_get_close_on_exit</refname>
<refpurpose>Control whether to close the bus connection during the event loop exit phase
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_set_close_on_exit</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>int <parameter>b</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_get_close_on_exit</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_set_close_on_exit()</function> may be used to enable or disable whether
the bus connection is automatically flushed (as in
<citerefentry><refentrytitle>sd_bus_flush</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
and closed (as in
<citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
during the exit phase of the event loop. This logic only applies to bus connections that are
attached to an
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
event loop, see
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
By default this mechanism is enabled and makes sure that any pending messages that have not been
written to the bus connection are written out when the event loop is shutting down. In some
cases this behaviour is not desirable, for example when the bus connection shall remain usable
until after the event loop exited. If <parameter>b</parameter> is true, the feature is enabled
(which is the default), otherwise disabled.</para>
<para><function>sd_bus_get_close_on_exit()</function> may be used to query the current setting
of this feature. It returns zero when the feature is disabled, and positive if enabled.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, <function>sd_bus_set_close_on_exit()</function> returns a non-negative
integer. On failure, it returns a negative errno-style error code.</para>
<para><function>sd_bus_get_close_on_exit()</function> returns 0 if the feature is currently
disabled or a positive integer if it is enabled. On failure, it returns a negative errno-style
error code.</para>
<refsect2>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-ECHILD</constant></term>
<listitem><para>The bus connection was created in a different process, library or module instance.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_flush</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>