systemd/man/sd_id128_randomize.xml

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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Copyright 2012 Lennart Poettering
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<refentry id="sd_id128_randomize">
<refentryinfo>
<title>sd_id128_randomize</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_id128_randomize</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_id128_randomize</refname>
<refpurpose>Generate 128-bit IDs</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_id128_randomize</function></funcdef>
<paramdef>sd_id128_t* <parameter>ret</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_id128_randomize()</function>
generates a new randomized 128-bit ID and returns it
in <parameter>ret</parameter>. Every invocation
returns a new randomly generated ID. This uses the
<filename>/dev/urandom</filename> kernel random number
generator.</para>
<para>Note that
<function>sd_id128_randomize()</function> always returns
a UUID v4-compatible ID.</para>
<para>For more information about the
<literal>sd_id128_t</literal> type, see
<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
<para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
<option>--new-id</option> option may be used as a
command-line front-end for
<function>sd_id128_randomize()</function>.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>The call returns 0 on success (in which
case <parameter>ret</parameter> is filled in), or a
negative errno-style error code.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_id128_randomize()</function> interface
is available as a shared library, which can be compiled
and linked to with the
<literal>libsystemd</literal> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>