--- /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">
+
+<!--
+ This file is part of systemd.
+
+ Copyright 2014 Zbigniew Jędrzejewski-Szmek
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<refentry id="sd_bus_message_append"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>sd_bus_message_append</title>
+ <productname>systemd</productname>
+
+ <authorgroup>
+ <author>
+ <contrib>A monkey with a typewriter</contrib>
+ <firstname>Zbigniew</firstname>
+ <surname>Jędrzejewski-Szmek</surname>
+ <email>zbyszek@in.waw.pl</email>
+ </author>
+ </authorgroup>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>sd_bus_message_append</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_bus_message_append</refname>
+
+ <refpurpose>Attach fields to a D-Bus message based on a type
+ string</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int sd_bus_message_append</funcdef>
+ <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
+ <paramdef>const char *<parameter>types</parameter></paramdef>
+ <paramdef>…</paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>The <function>sd_bus_message_append()</function> function
+ appends a sequence of fields to the D-Bus message object
+ <parameter>m</parameter>. The type string
+ <parameter>types</parameter> describes the types of the field
+ arguments that follow. For each type specified in the type string,
+ one or more arguments need to be specified, in the same order as
+ declared in the type string.</para>
+
+ <para>The type string is composed of the elements shown in the
+ table below. It contains zero or more single "complete types".
+ Each complete type may be one of the basic types or a fully
+ described container type. A container type may be a structure with
+ the contained types, a variant, an array with its element type, or
+ a dictionary entry with the contained types. The type string is
+ <constant>NUL</constant>-terminated.</para>
+
+ <para>In case of a basic type, one argument of the corresponding
+ type is expected.</para>
+
+ <para>A structure is denoted by a sequence of complete types
+ between <literal>(</literal> and <literal>)</literal>. This
+ sequence cannot be empty — it must contain at least one type.
+ Arguments corresponding to this nested sequence follow the same
+ rules as if they were not nested.</para>
+
+ <para>A variant is denoted by <literal>v</literal>. Corresponding
+ arguments must begin with a type string denoting a complete type,
+ and following that, arguments corresponding to the specified type.
+ </para>
+
+ <para>An array is denoted by <literal>a</literal> followed by a
+ complete type. Corresponding arguments must begin with the number of
+ entries in the array, followed by the entries themselves,
+ matching the element type of the array.</para>
+
+ <para>A dictionary is an array of dictionary entries, denoted by
+ <literal>a</literal> followed by a pair of complete types between
+ <literal>{</literal> and <literal>}</literal>. The first of those
+ types must be a basic type. Corresponding arguments must begin
+ with the number of dictionary entries, followed by a pair of
+ values for each entry matching the element type of
+ the dictionary entries.</para>
+
+ <para>For further details on the D-Bus type system, please consult
+ the <ulink
+ url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">D-Bus
+ Specification</ulink>.</para>
+
+ <table>
+ <title>Item type specifiers</title>
+
+ <tgroup cols='5'>
+ <xi:include href="sd_bus_message_append_basic.xml" xpointer="xpointer(//table[@id='format-specifiers'])//colspec" />
+ <xi:include href="sd_bus_message_append_basic.xml" xpointer="xpointer(//table[@id='format-specifiers']//thead)" />
+
+ <tbody>
+ <xi:include href="sd_bus_message_append_basic.xml" xpointer="xpointer(//table[@id='format-specifiers']//tbody/*)" />
+
+ <row>
+ <entry><literal>a</literal></entry>
+ <entry><constant>SD_BUS_TYPE_ARRAY</constant></entry>
+ <entry>array</entry>
+ <entry>determined by array type and size</entry>
+ <entry>int, followed by array contents</entry>
+ </row>
+
+ <row>
+ <entry><literal>v</literal></entry>
+ <entry><constant>SD_BUS_TYPE_VARIANT</constant></entry>
+ <entry>variant</entry>
+ <entry>determined by the type argument</entry>
+ <entry>signature string, followed by variant contents</entry>
+ </row>
+
+ <row>
+ <entry><literal>(</literal></entry>
+ <entry><constant>SD_BUS_TYPE_STRUCT_BEGIN</constant></entry>
+ <entry>array start</entry>
+ <entry morerows="1">determined by the nested types</entry>
+ <entry morerows="1">structure contents</entry>
+ </row>
+ <row>
+ <entry><literal>)</literal></entry>
+ <entry><constant>SD_BUS_TYPE_STRUCT_END</constant></entry>
+ <entry>array end</entry>
+ </row>
+
+ <row>
+ <entry><literal>{</literal></entry>
+ <entry><constant>SD_BUS_TYPE_DICT_ENTRY_BEGIN</constant></entry>
+ <entry>dictionary entry start</entry>
+ <entry morerows="1">determined by the nested types</entry>
+ <entry morerows="1">dictionary contents</entry>
+ </row>
+ <row>
+ <entry><literal>}</literal></entry>
+ <entry><constant>SD_BUS_TYPE_DICT_ENTRY_END</constant></entry>
+ <entry>dictionary entry end</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>For types "s" and "g" (unicode string or signature), the pointer may be
+ <constant>NULL</constant>, which is equivalent to an empty string. See
+ <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for the precise interpretation of those and other types.</para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Types String Grammar</title>
+
+ <programlisting>types ::= complete_type*
+complete_type ::= basic_type | variant | structure | array | dictionary
+basic_type ::= "y" | "n" | "q" | "u" | "i" | "x" | "t" | "d" |
+ "b" | "h" |
+ "s" | "o" | "g"
+variant ::= "v"
+structure ::= "(" complete_type+ ")"
+array ::= "a" complete_type
+dictionary ::= "a" "{" basic_type complete_type "}"
+</programlisting>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <para>Append a single basic type (the string <literal>a string</literal>):
+ </para>
+
+ <programlisting>sd_bus_message *m;
+…
+sd_bus_message_append(m, "s", "a string");</programlisting>
+
+ <para>Append all types of integers:</para>
+
+ <programlisting>uint8_t y = 1;
+int16_t n = 2;
+uint16_t q = 3;
+int32_t i = 4;
+uint32_t u = 5;
+int32_t x = 6;
+uint32_t t = 7;
+double d = 8.0;
+sd_bus_message_append(m, "ynqiuxtd", y, n, q, i, u, x, t, d);</programlisting>
+
+ <para>Append a structure composed of a string and a D-Bus path:</para>
+
+ <programlisting>sd_bus_message_append(m, "(so)", "a string", "/a/path");
+</programlisting>
+
+ <para>Append an array of UNIX file descriptors:</para>
+
+ <programlisting>sd_bus_message_append(m, "ah", 3, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO);
+</programlisting>
+
+ <para>Append a variant, with the real type "g" (signature),
+ and value "sdbusisgood":</para>
+
+ <programlisting>sd_bus_message_append(m, "v", "g", "sdbusisgood");</programlisting>
+
+ <para>Append a dictionary containing the mapping {1=>"a", 2=>"b", 3=>""}:
+ </para>
+
+ <programlisting>sd_bus_message_append(m, "a{is}", 3, 1, "a", 2, "b", 3, NULL);
+ </programlisting>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success, this call returns 0 or a positive
+ integer. On failure, this call returns a negative
+ errno-style error code.</para>
+ </refsect1>
+
+ <xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />
+
+ <refsect1>
+ <title>Notes</title>
+
+ <para><function>sd_bus_open_user()</function> and other functions
+ described here are available as a shared library, which can be
+ compiled and linked to with the
+ <constant>libelogind-bus</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ file.</para>
+ </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_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_message_append_array</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>
~ianmdlvl / elogind.git / blobdiff