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analyze: change behaviour of combined --to/from--pattern
[elogind.git] / man / sd_id128_randomize.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
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8   Copyright 2012 Lennart Poettering
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23
24 <refentry id="sd_id128_randomize">
25
26   <refentryinfo>
27     <title>sd_id128_randomize</title>
28     <productname>systemd</productname>
29
30     <authorgroup>
31       <author>
32         <contrib>Developer</contrib>
33         <firstname>Lennart</firstname>
34         <surname>Poettering</surname>
35         <email>lennart@poettering.net</email>
36       </author>
37     </authorgroup>
38   </refentryinfo>
39
40   <refmeta>
41     <refentrytitle>sd_id128_randomize</refentrytitle>
42     <manvolnum>3</manvolnum>
43   </refmeta>
44
45   <refnamediv>
46     <refname>sd_id128_randomize</refname>
47     <refpurpose>Generate 128-bit IDs</refpurpose>
48   </refnamediv>
49
50   <refsynopsisdiv>
51     <funcsynopsis>
52       <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
53
54       <funcprototype>
55         <funcdef>int <function>sd_id128_randomize</function></funcdef>
56         <paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
57       </funcprototype>
58
59     </funcsynopsis>
60   </refsynopsisdiv>
61
62   <refsect1>
63     <title>Description</title>
64
65     <para><function>sd_id128_randomize()</function> generates a new
66     randomized 128-bit ID and returns it in
67     <parameter>ret</parameter>. Every invocation returns a new
68     randomly generated ID. This uses the
69     <filename>/dev/urandom</filename> kernel random number
70     generator.</para>
71
72     <para>Note that <function>sd_id128_randomize()</function> always
73     returns a UUID v4-compatible ID.</para>
74
75     <para>For more information about the <literal>sd_id128_t</literal>
76     type, see
77     <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
78
79     <para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
80     <option>--new-id</option> option may be used as a command line
81     front-end for <function>sd_id128_randomize()</function>.</para>
82   </refsect1>
83
84   <refsect1>
85     <title>Return Value</title>
86
87     <para>The call returns 0 on success (in which case
88     <parameter>ret</parameter> is filled in), or a negative
89     errno-style error code.</para>
90   </refsect1>
91
92   <refsect1>
93     <title>Notes</title>
94
95     <para>The <function>sd_id128_randomize()</function> interface is
96     available as a shared library, which can be compiled and linked to
97     with the
98     <literal>libsystemd</literal> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
99     file.</para>
100   </refsect1>
101
102   <refsect1>
103     <title>See Also</title>
104
105     <para>
106       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
107       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
108       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
109       <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
110       <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
111     </para>
112   </refsect1>
113
114 </refentry>