--- /dev/null
+<?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">
+
+<!--
+ This file is part of systemd.
+
+ Copyright 2012 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<refentry id="sd_id128_get_machine">
+
+ <refentryinfo>
+ <title>sd_id128_get_machine</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_get_machine</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_id128_get_machine</refname>
+ <refname>sd_id128_get_boot</refname>
+ <refpurpose>Retrieve 128 bit IDs</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int <function>sd_id128_get_machine</function></funcdef>
+ <paramdef>sd_id128_t* <parameter>ret</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_id128_get_boot</function></funcdef>
+ <paramdef>sd_id128_t* <parameter>ret</parameter></paramdef>
+ </funcprototype>
+
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>sd_id128_get_machine()</function>
+ returns the machine ID of the executing host. This
+ reads and parses the
+ <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ file. This function caches the machine ID internally
+ to make retrieving the machine ID a cheap
+ operation.</para>
+
+ <para><function>sd_id128_get_boot()</function> returns
+ the boot ID of the executing kernel. This reads and
+ parses the
+ <filename>/proc/sys/kernel/random/boot_id</filename>
+ file exposed by the kernel. It is randomly generated
+ early at boot and is unique for every running kernel
+ instance. See
+ <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>
+ for more information. This function also internally
+ caches the returned ID to make this call a cheap
+ operation.</para>
+
+ <para>Note that
+ <function>sd_id128_get_boot()</function> always returns
+ a UUID v4 compatible
+ ID. <function>sd_id128_get_machine()</function> will
+ also return a UUID v4 compatible ID on new
+ installations, but might not on older. It is possible
+ to convert the machine ID into an UUID v4 compatible
+ one. For more information see
+ <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
+ <para>For more information about the
+ <literal>sd_id128_t</literal> type see
+ <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>The two calls return 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_get_machine()</function>
+ and <function>sd_id128_get_boot()</function>
+ interfaces are available as shared library, which can
+ be compiled and linked to with the
+ <literal>libsystemd-id128</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_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>
~ianmdlvl / elogind.git / blobdiff