man/sd_bus_message_append_string_memfd.xml

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   8   Copyright 2014 Zbigniew Jędrzejewski-Szmek
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  23
  24 <refentry id="sd_bus_message_append_string_memfd"
  25           xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27   <refentryinfo>
  28     <title>sd_bus_message_append_string_memfd</title>
  29     <productname>systemd</productname>
  30
  31     <authorgroup>
  32       <author>
  33         <contrib>A monkey with a typewriter</contrib>
  34         <firstname>Zbigniew</firstname>
  35         <surname>Jędrzejewski-Szmek</surname>
  36         <email>zbyszek@in.waw.pl</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40
  41   <refmeta>
  42     <refentrytitle>sd_bus_message_append_string_memfd</refentrytitle>
  43     <manvolnum>3</manvolnum>
  44   </refmeta>
  45
  46   <refnamediv>
  47     <refname>sd_bus_message_append_string_memfd</refname>
  48     <refname>sd_bus_message_append_string_iovec</refname>
  49     <refname>sd_bus_message_append_string_space</refname>
  50
  51     <refpurpose>Attach a string to a message</refpurpose>
  52   </refnamediv>
  53
  54   <refsynopsisdiv>
  55     <funcsynopsis>
  56       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  57
  58       <funcprototype>
  59         <funcdef>int sd_bus_message_append_string_memfd</funcdef>
  60         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  61         <paramdef>int <parameter>memfd</parameter></paramdef>
  62       </funcprototype>
  63
  64       <funcprototype>
  65         <funcdef>int sd_bus_message_append_string_iovec</funcdef>
  66         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  67         <paramdef>const struct iovec *<parameter>iov</parameter></paramdef>
  68         <paramdef>unsigned <parameter>n</parameter></paramdef>
  69       </funcprototype>
  70
  71       <funcprototype>
  72         <funcdef>int sd_bus_message_append_string_space</funcdef>
  73         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  74         <paramdef>size_t <parameter>size</parameter></paramdef>
  75         <paramdef>char **<parameter>s</parameter></paramdef>
  76       </funcprototype>
  77     </funcsynopsis>
  78   </refsynopsisdiv>
  79
  80   <refsect1>
  81     <title>Description</title>
  82
  83     <para>The functions
  84     <function>sd_bus_message_append_string_memfd</function> and
  85     <function>sd_bus_message_append_string_iovec</function> can be
  86     used to append a single string (item of type <literal>s</literal>)
  87     to message <parameter>m</parameter>.</para>
  88
  89     <para>In case of
  90     <function>sd_bus_message_append_string_memfd</function>, the
  91     contents of <parameter>memfd</parameter> are the string. They must
  92     satisfy the same constraints as described for the
  93     <literal>s</literal> type in
  94     <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  95
  96     <para>In case of
  97     <function>sd_bus_message_append_string_iovec</function>, the
  98     payload of <parameter>iov</parameter> is the string. It must
  99     satisfy the same constraints as described for the
 100     <literal>s</literal> type in
 101     <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
 102
 103     <para>The <parameter>iov</parameter> argument must point to
 104     <parameter>n</parameter> <structname>struct iovec</structname>
 105     structures. Each structure may have the
 106     <structname>iov_base</structname> field set, in which case the
 107     memory pointed to will be copied into the message, or unset, in
 108     which case a block of spaces (ASCII 32) of length
 109     <structname>iov_len</structname> will be inserted. The
 110     memory pointed at by <parameter>iov</parameter> may be changed
 111     after this call.</para>
 112
 113     <para>The
 114     <function>sd_bus_message_append_string_space</function> function appends
 115     space for a string to message <parameter>m</parameter>. It behaves
 116     similar to <function>sd_bus_message_append_basic</function> with
 117     type <literal>s</literal>, but instead of copying a string into
 118     the message, it returns a pointer to the destination area to
 119     the caller in pointer <parameter>p</parameter>. Space for the string
 120     of length <parameter>size</parameter> plus the terminating
 121     <constant>NUL</constant> is allocated.</para>
 122   </refsect1>
 123
 124   <refsect1>
 125     <title>Return Value</title>
 126
 127     <para>On success, those calls return 0 or a positive integer. On
 128     failure, they returns a negative errno-style error code.</para>
 129   </refsect1>
 130
 131   <xi:include href="sd_bus_message_append_basic.xml" xpointer="errors" />
 132
 133   <refsect1>
 134     <title>Notes</title>
 135
 136     <para>The functions described here are available as a shared library,
 137     which can be compiled and linked to with the
 138     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 139     file.</para>
 140   </refsect1>
 141
 142   <refsect1>
 143     <title>See Also</title>
 144
 145     <para>
 146       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 147       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 148       <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 149       <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink>
 150     </para>
 151   </refsect1>
 152
 153 </refentry>