man/sd_id128_randomize.xml

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  11   Copyright 2012 Lennart Poettering
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  26
  27 <refentry id="sd_id128_randomize">
  28
  29   <refentryinfo>
  30     <title>sd_id128_randomize</title>
  31     <productname>systemd</productname>
  32
  33     <authorgroup>
  34       <author>
  35         <contrib>Developer</contrib>
  36         <firstname>Lennart</firstname>
  37         <surname>Poettering</surname>
  38         <email>lennart@poettering.net</email>
  39       </author>
  40     </authorgroup>
  41   </refentryinfo>
  42
  43   <refmeta>
  44     <refentrytitle>sd_id128_randomize</refentrytitle>
  45     <manvolnum>3</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>sd_id128_randomize</refname>
  50     <refpurpose>Generate 128-bit IDs</refpurpose>
  51   </refnamediv>
  52
  53   <refsynopsisdiv>
  54     <funcsynopsis>
  55       <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
  56
  57       <funcprototype>
  58         <funcdef>int <function>sd_id128_randomize</function></funcdef>
  59         <paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
  60       </funcprototype>
  61
  62     </funcsynopsis>
  63   </refsynopsisdiv>
  64
  65   <refsect1>
  66     <title>Description</title>
  67
  68     <para><function>sd_id128_randomize()</function> generates a new
  69     randomized 128-bit ID and returns it in
  70     <parameter>ret</parameter>. Every invocation returns a new
  71     randomly generated ID. This uses the
  72     <filename>/dev/urandom</filename> kernel random number
  73     generator.</para>
  74
  75     <para>Note that <function>sd_id128_randomize()</function> always
  76     returns a UUID v4-compatible ID.</para>
  77
  78     <para>For more information about the <literal>sd_id128_t</literal>
  79     type, see
  80     <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  81
  82     <para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  83     <option>--new-id</option> option may be used as a command line
  84     front-end for <function>sd_id128_randomize()</function>.</para>
  85   </refsect1>
  86
  87   <refsect1>
  88     <title>Return Value</title>
  89
  90     <para>The call returns 0 on success (in which case
  91     <parameter>ret</parameter> is filled in), or a negative
  92     errno-style error code.</para>
  93   </refsect1>
  94
  95   <refsect1>
  96     <title>Notes</title>
  97
  98     <para>The <function>sd_id128_randomize()</function> interface is
  99     available as a shared library, which can be compiled and linked to
 100     with the
 101     <literal>libsystemd</literal> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 102     file.</para>
 103   </refsect1>
 104
 105   <refsect1>
 106     <title>See Also</title>
 107
 108     <para>
 109       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 110       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 111       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 112       <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
 113       <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 114     </para>
 115   </refsect1>
 116
 117 </refentry>