man/sd_id128_randomize.xml

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  10   Copyright 2012 Lennart Poettering
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  25
  26 <refentry id="sd_id128_randomize">
  27
  28   <refentryinfo>
  29     <title>sd_id128_randomize</title>
  30     <productname>systemd</productname>
  31
  32     <authorgroup>
  33       <author>
  34         <contrib>Developer</contrib>
  35         <firstname>Lennart</firstname>
  36         <surname>Poettering</surname>
  37         <email>lennart@poettering.net</email>
  38       </author>
  39     </authorgroup>
  40   </refentryinfo>
  41
  42   <refmeta>
  43     <refentrytitle>sd_id128_randomize</refentrytitle>
  44     <manvolnum>3</manvolnum>
  45   </refmeta>
  46
  47   <refnamediv>
  48     <refname>sd_id128_randomize</refname>
  49     <refpurpose>Generate 128-bit IDs</refpurpose>
  50   </refnamediv>
  51
  52   <refsynopsisdiv>
  53     <funcsynopsis>
  54       <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
  55
  56       <funcprototype>
  57         <funcdef>int <function>sd_id128_randomize</function></funcdef>
  58         <paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
  59       </funcprototype>
  60
  61     </funcsynopsis>
  62   </refsynopsisdiv>
  63
  64   <refsect1>
  65     <title>Description</title>
  66
  67     <para><function>sd_id128_randomize()</function> generates a new
  68     randomized 128-bit ID and returns it in
  69     <parameter>ret</parameter>. Every invocation returns a new
  70     randomly generated ID. This uses the
  71     <filename>/dev/urandom</filename> kernel random number
  72     generator.</para>
  73
  74     <para>Note that <function>sd_id128_randomize()</function> always
  75     returns a UUID v4-compatible ID.</para>
  76
  77     <para>For more information about the <literal>sd_id128_t</literal>
  78     type, see
  79     <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  80
  81     <para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  82     <option>--new-id128</option> option may be used as a command line
  83     front-end for <function>sd_id128_randomize()</function>.</para>
  84   </refsect1>
  85
  86   <refsect1>
  87     <title>Return Value</title>
  88
  89     <para>The call returns 0 on success (in which case
  90     <parameter>ret</parameter> is filled in), or a negative
  91     errno-style error code.</para>
  92   </refsect1>
  93
  94   <refsect1>
  95     <title>Notes</title>
  96
  97     <para>The <function>sd_id128_randomize()</function> interface is
  98     available as a shared library, which can be compiled and linked to
  99     with the
 100     <literal>libsystemd</literal> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 101     file.</para>
 102   </refsect1>
 103
 104   <refsect1>
 105     <title>See Also</title>
 106
 107     <para>
 108       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 109       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 110       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 111       <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
 112       <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 113     </para>
 114   </refsect1>
 115
 116 </refentry>