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Diffstat (limited to 'man/sd_bus_message_open_container.xml')
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diff --git a/man/sd_bus_message_open_container.xml b/man/sd_bus_message_open_container.xml new file mode 100644 index 0000000..d08382e --- /dev/null +++ b/man/sd_bus_message_open_container.xml @@ -0,0 +1,211 @@ +<?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_message_open_container" + xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_bus_message_open_container</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_bus_message_open_container</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_bus_message_open_container</refname> + <refname>sd_bus_message_close_container</refname> + <refname>sd_bus_message_enter_container</refname> + <refname>sd_bus_message_exit_container</refname> + + <refpurpose>Create and move between containers in D-Bus messages</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int sd_bus_message_open_container</funcdef> + <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> + <paramdef>char <parameter>type</parameter></paramdef> + <paramdef>const char *<parameter>contents</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int sd_bus_message_close_container</funcdef> + <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int sd_bus_message_enter_container</funcdef> + <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> + <paramdef>char <parameter>type</parameter></paramdef> + <paramdef>const char *<parameter>contents</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int sd_bus_message_exit_container</funcdef> + <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_bus_message_open_container()</function> appends a new container to the message + <parameter>m</parameter>. After opening a new container, it can be filled with content using + <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and similar functions. Containers behave like a stack. To nest containers inside each other, call + <function>sd_bus_message_open_container()</function> multiple times without calling + <function>sd_bus_message_close_container()</function> in between. Each container will be nested inside the + previous container. <parameter>type</parameter> represents the container type and should be one of + <literal>r</literal>, <literal>a</literal>, <literal>v</literal> or <literal>e</literal> as described in + <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + Instead of literals, the corresponding constants <constant>SD_BUS_TYPE_STRUCT</constant>, + <constant>SD_BUS_TYPE_ARRAY</constant>, <constant>SD_BUS_TYPE_VARIANT</constant> or + <constant>SD_BUS_TYPE_DICT_ENTRY</constant> can also be used. <parameter>contents</parameter> describes + the type of the container's elements and should be a D-Bus type string following the rules described in + <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + </para> + + <para><function>sd_bus_message_close_container()</function> closes the last container opened with + <function>sd_bus_message_open_container()</function>. On success, the write pointer of the message + <parameter>m</parameter> is positioned after the closed container in its parent container or in + <parameter>m</parameter> itself if there is no parent container.</para> + + <para><function>sd_bus_message_enter_container()</function> enters the next container of the message + <parameter>m</parameter> for reading. It behaves mostly the same as + <function>sd_bus_message_open_container()</function>. Entering a container allows reading its contents + with + <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and similar functions. <parameter>type</parameter> and <parameter>contents</parameter> are the same as in + <function>sd_bus_message_open_container()</function>.</para> + + <para><function>sd_bus_message_exit_container()</function> exits the scope of the last container entered + with <function>sd_bus_message_enter_container()</function>. It behaves mostly the same as + <function>sd_bus_message_close_container()</function>. Note that + <function>sd_bus_message_exit_container()</function> may only be called after iterating through all + members of the container, i.e. reading or skipping over them. Use + <citerefentry><refentrytitle>sd_bus_message_skip</refentrytitle><manvolnum>3</manvolnum></citerefentry> + to skip over fields of a container in order to be able to exit the container with + <function>sd_bus_message_exit_container()</function> without reading all members.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>On success, these functions return a non-negative integer. + <function>sd_bus_message_open_container()</function> and <function>sd_bus_message_close_container()</function> + return 0. + <function>sd_bus_message_enter_container()</function> returns 1 if it successfully opened a new container, and 0 if + that was not possible because the end of the currently open container or message was reached. + <function>sd_bus_message_exit_container()</function> returns 1 on success. + On failure, all of these functions return a negative errno-style error code.</para> + + <refsect2> + <title>Errors</title> + + <para>Returned errors may indicate the following problems:</para> + + <variablelist> + <varlistentry> + <term><constant>-EINVAL</constant></term> + + <listitem><para><parameter>m</parameter> or <parameter>contents</parameter> are + <constant>NULL</constant> or <parameter>type</parameter> is invalid.</para> + + <xi:include href="version-info.xml" xpointer="v246"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EBADMSG</constant></term> + + <listitem><para>Message <parameter>m</parameter> has invalid structure.</para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ENXIO</constant></term> + + <listitem><para>Message <parameter>m</parameter> does not have a container of type + <parameter>type</parameter> at the current position, or the contents do not match + <parameter>contents</parameter>.</para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EPERM</constant></term> + + <listitem><para>The message <parameter>m</parameter> is already sealed.</para> + + <xi:include href="version-info.xml" xpointer="v246"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ESTALE</constant></term> + + <listitem><para>The message <parameter>m</parameter> is in an invalid state.</para> + + <xi:include href="version-info.xml" xpointer="v246"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-ENOMEM</constant></term> + + <listitem><para>Memory allocation failed.</para> + + <xi:include href="version-info.xml" xpointer="v246"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>-EBUSY</constant></term> + + <listitem><para><function>sd_bus_message_exit_container()</function> was called but there are + unread members left in the container.</para> + + <xi:include href="version-info.xml" xpointer="v247"/></listitem> + </varlistentry> + </variablelist> + </refsect2> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>Examples</title> + + <example> + <title>Append an array of strings to a message</title> + + <programlisting><xi:include href="sd-bus-container-append.c" parse="text" /></programlisting> + </example> + + <example> + <title>Read an array of strings from a message</title> + + <programlisting><xi:include href="sd-bus-container-read.c" parse="text" /></programlisting> + </example> + </refsect1> + + <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_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_message_skip</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> + </para> + </refsect1> + +</refentry> |