man/sd_bus_message_append_string_memfd.xml

   1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   This file is part of systemd.
   9
  10   Copyright 2014 Zbigniew Jędrzejewski-Szmek
  11 -->
  12
  13 <refentry id="sd_bus_message_append_string_memfd"
  14           xmlns:xi="http://www.w3.org/2001/XInclude">
  15
  16   <refentryinfo>
  17     <title>sd_bus_message_append_string_memfd</title>
  18     <productname>systemd</productname>
  19
  20     <authorgroup>
  21       <author>
  22         <contrib>A monkey with a typewriter</contrib>
  23         <firstname>Zbigniew</firstname>
  24         <surname>Jędrzejewski-Szmek</surname>
  25         <email>zbyszek@in.waw.pl</email>
  26       </author>
  27     </authorgroup>
  28   </refentryinfo>
  29
  30   <refmeta>
  31     <refentrytitle>sd_bus_message_append_string_memfd</refentrytitle>
  32     <manvolnum>3</manvolnum>
  33   </refmeta>
  34
  35   <refnamediv>
  36     <refname>sd_bus_message_append_string_memfd</refname>
  37     <refname>sd_bus_message_append_string_iovec</refname>
  38     <refname>sd_bus_message_append_string_space</refname>
  39
  40     <refpurpose>Attach a string to a message</refpurpose>
  41   </refnamediv>
  42
  43   <refsynopsisdiv>
  44     <funcsynopsis>
  45       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  46
  47       <funcprototype>
  48         <funcdef>int sd_bus_message_append_string_memfd</funcdef>
  49         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  50         <paramdef>int <parameter>memfd</parameter></paramdef>
  51       </funcprototype>
  52
  53       <funcprototype>
  54         <funcdef>int sd_bus_message_append_string_iovec</funcdef>
  55         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  56         <paramdef>const struct iovec *<parameter>iov</parameter></paramdef>
  57         <paramdef>unsigned <parameter>n</parameter></paramdef>
  58       </funcprototype>
  59
  60       <funcprototype>
  61         <funcdef>int sd_bus_message_append_string_space</funcdef>
  62         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  63         <paramdef>size_t <parameter>size</parameter></paramdef>
  64         <paramdef>char **<parameter>s</parameter></paramdef>
  65       </funcprototype>
  66     </funcsynopsis>
  67   </refsynopsisdiv>
  68
  69   <refsect1>
  70     <title>Description</title>
  71
  72     <para>The functions
  73     <function>sd_bus_message_append_string_memfd</function> and
  74     <function>sd_bus_message_append_string_iovec</function> can be
  75     used to append a single string (item of type <literal>s</literal>)
  76     to message <parameter>m</parameter>.</para>
  77
  78     <para>In case of
  79     <function>sd_bus_message_append_string_memfd</function>, the
  80     contents of <parameter>memfd</parameter> are the string. They must
  81     satisfy the same constraints as described for the
  82     <literal>s</literal> type in
  83     <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  84
  85     <para>In case of
  86     <function>sd_bus_message_append_string_iovec</function>, the
  87     payload of <parameter>iov</parameter> is the string. It must
  88     satisfy the same constraints as described for the
  89     <literal>s</literal> type in
  90     <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  91
  92     <para>The <parameter>iov</parameter> argument must point to
  93     <parameter>n</parameter> <structname>struct iovec</structname>
  94     structures. Each structure may have the
  95     <structname>iov_base</structname> field set, in which case the
  96     memory pointed to will be copied into the message, or unset, in
  97     which case a block of spaces (ASCII 32) of length
  98     <structname>iov_len</structname> will be inserted. The
  99     memory pointed at by <parameter>iov</parameter> may be changed
 100     after this call.</para>
 101
 102     <para>The
 103     <function>sd_bus_message_append_string_space</function> function appends
 104     space for a string to message <parameter>m</parameter>. It behaves
 105     similar to <function>sd_bus_message_append_basic</function> with
 106     type <literal>s</literal>, but instead of copying a string into
 107     the message, it returns a pointer to the destination area to
 108     the caller in pointer <parameter>p</parameter>. Space for the string
 109     of length <parameter>size</parameter> plus the terminating
 110     <constant>NUL</constant> is allocated.</para>
 111   </refsect1>
 112
 113   <refsect1>
 114     <title>Return Value</title>
 115
 116     <para>On success, those calls return 0 or a positive integer. On
 117     failure, they returns a negative errno-style error code.</para>
 118   </refsect1>
 119
 120   <xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />
 121
 122   <refsect1>
 123     <title>Notes</title>
 124
 125     <para>The functions described here are available as a shared library,
 126     which can be compiled and linked to with the
 127     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 128     file.</para>
 129   </refsect1>
 130
 131   <refsect1>
 132     <title>See Also</title>
 133
 134     <para>
 135       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 136       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 137       <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 138       <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink>
 139     </para>
 140   </refsect1>
 141
 142 </refentry>