man/sd_id128_randomize.xml

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   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
   9 <refentry id="sd_id128_randomize" xmlns:xi="http://www.w3.org/2001/XInclude">
  10
  11   <refentryinfo>
  12     <title>sd_id128_randomize</title>
  13     <productname>systemd</productname>
  14
  15     <authorgroup>
  16       <author>
  17         <contrib>Developer</contrib>
  18         <firstname>Lennart</firstname>
  19         <surname>Poettering</surname>
  20         <email>lennart@poettering.net</email>
  21       </author>
  22     </authorgroup>
  23   </refentryinfo>
  24
  25   <refmeta>
  26     <refentrytitle>sd_id128_randomize</refentrytitle>
  27     <manvolnum>3</manvolnum>
  28   </refmeta>
  29
  30   <refnamediv>
  31     <refname>sd_id128_randomize</refname>
  32     <refpurpose>Generate 128-bit IDs</refpurpose>
  33   </refnamediv>
  34
  35   <refsynopsisdiv>
  36     <funcsynopsis>
  37       <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
  38
  39       <funcprototype>
  40         <funcdef>int <function>sd_id128_randomize</function></funcdef>
  41         <paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
  42       </funcprototype>
  43
  44     </funcsynopsis>
  45   </refsynopsisdiv>
  46
  47   <refsect1>
  48     <title>Description</title>
  49
  50     <para><function>sd_id128_randomize()</function> generates a new
  51     randomized 128-bit ID and returns it in
  52     <parameter>ret</parameter>. Every invocation returns a new
  53     randomly generated ID. This uses the
  54     <filename>/dev/urandom</filename> kernel random number
  55     generator.</para>
  56
  57     <para>Note that <function>sd_id128_randomize()</function> always
  58     returns a UUID v4-compatible ID.</para>
  59
  60     <para>For more information about the <literal>sd_id128_t</literal>
  61     type, see
  62     <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  63
  64     <para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  65     <option>--new-id128</option> option may be used as a command line
  66     front-end for <function>sd_id128_randomize()</function>.</para>
  67   </refsect1>
  68
  69   <refsect1>
  70     <title>Return Value</title>
  71
  72     <para>The call returns 0 on success (in which case
  73     <parameter>ret</parameter> is filled in), or a negative
  74     errno-style error code.</para>
  75   </refsect1>
  76
  77   <xi:include href="libsystemd-pkgconfig.xml" />
  78
  79   <refsect1>
  80     <title>See Also</title>
  81
  82     <para>
  83       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  84       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  85       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  86       <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
  87       <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  88     </para>
  89   </refsect1>
  90
  91 </refentry>