systemd/man/sd_bus_message_set_expect_reply.xml
2018-08-02 15:49:45 +02:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<!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_message_set_expect_reply" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_message_set_expect_reply</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_set_expect_reply</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_set_expect_reply</refname>
<refname>sd_bus_message_get_expect_reply</refname>
<refname>sd_bus_message_set_auto_start</refname>
<refname>sd_bus_message_get_auto_start</refname>
<refpurpose>Set and query bus message metadata</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_message_set_expect_reply</function></funcdef>
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
<paramdef>int <parameter>b</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_message_get_expect_reply</function></funcdef>
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_message_set_auto_start</function></funcdef>
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
<paramdef>int <parameter>b</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_message_get_auto_start</function></funcdef>
<paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_message_set_expect_reply()</function> sets or clears the
<constant>NO_REPLY_EXPECTED</constant> flag on the message <parameter>m</parameter>. This flag
matters only for method call messages and is used to specify that no method return or error
reply is expected. It is ignored for other types. Thus, for a method call message, calling
<programlisting>sd_bus_message_set_expect_reply(…, 0)</programlisting> sets the flag and
suppresses the reply.</para>
<para><function>sd_bus_message_get_expect_reply()</function> checks if the
<constant>NO_REPLY_EXPECTED</constant> flag is set on the message <parameter>m</parameter>. It
will return positive if it is not set, and zero if it is.</para>
<para><function>sd_bus_message_set_auto_start()</function> sets or clears the
<constant>NO_AUTO_START</constant> flag on the message <parameter>m</parameter>. When the flag
is set the bus must not launch an owner for the destination name in response to this message.
Calling
<programlisting>sd_bus_message_set_auto_start(…, 0)</programlisting> sets the flag.
</para>
<para><function>sd_bus_message_get_auto_start()</function> checks if the
<constant>NO_AUTO_START</constant> flag is set on the message <parameter>m</parameter>. It
will return positive if it is not set, and zero if it is.</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>-EINVAL</constant></term>
<listitem><para>The <parameter>message</parameter> parameter is
<constant>NULL</constant>.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-EPERM</constant></term>
<listitem><para>The message <parameter>message</parameter> is sealed
when trying to set a flag.</para>
<para>The message <parameter>message</parameter> has wrong
type.</para>
</listitem>
</varlistentry>
</variablelist>
</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_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>