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Diffstat (limited to 'src/libsystemd/sd_bus_message_append.xml')
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diff --git a/src/libsystemd/sd_bus_message_append.xml b/src/libsystemd/sd_bus_message_append.xml new file mode 100644 index 0000000000..c222d0fd0e --- /dev/null +++ b/src/libsystemd/sd_bus_message_append.xml @@ -0,0 +1,269 @@ +<?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>libsystemd-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> |