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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 | ||
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2012 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
24 | <refentry id="sd_journal_get_realtime_usec"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>sd_journal_get_realtime_usec</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_journal_get_realtime_usec</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_journal_get_realtime_usec</refname> | |
47 | <refname>sd_journal_get_monotonic_usec</refname> | |
48 | <refpurpose>Read timestamps from the current journal entry</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <funcsynopsis> | |
53 | <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> | |
54 | ||
55 | <funcprototype> | |
56 | <funcdef>int <function>sd_journal_get_realtime_usec</function></funcdef> | |
57 | <paramdef>sd_journal* <parameter>j</parameter></paramdef> | |
58 | <paramdef>uint64_t* <parameter>usec</parameter></paramdef> | |
59 | </funcprototype> | |
60 | ||
61 | <funcprototype> | |
62 | <funcdef>int <function>sd_journal_get_monotonic_usec</function></funcdef> | |
63 | <paramdef>sd_journal* <parameter>j</parameter></paramdef> | |
64 | <paramdef>uint64_t* <parameter>usec</parameter></paramdef> | |
65 | <paramdef>sd_id128_t* <parameter>boot_id</parameter></paramdef> | |
66 | </funcprototype> | |
67 | ||
68 | </funcsynopsis> | |
69 | </refsynopsisdiv> | |
70 | ||
71 | <refsect1> | |
72 | <title>Description</title> | |
73 | ||
74 | <para><function>sd_journal_get_realtime_usec()</function> | |
b59866ae | 75 | gets the realtime (wallclock) timestamp of the |
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76 | current journal entry. It takes two arguments: the |
77 | journal context object and a pointer to a 64 Bit | |
78 | unsigned integer to store the timestamp in. The | |
79 | timestamp is in microseconds since the epoch, | |
80 | i.e. CLOCK_REALTIME.</para> | |
81 | ||
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82 | <para><function>sd_journal_get_monotonic_usec()</function> |
83 | gets the monotonic timestamp of the current | |
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84 | journal entry. It takes three arguments: the journal |
85 | context object, a pointer to a 64 Bit unsigned integer | |
86 | to store the timestamp in as well as a 128 Bit ID | |
87 | buffer to store the boot ID of the monotonic timestamp | |
88 | in. The timestamp is in microseconds since boot-up of | |
89 | the specific boot, i.e. CLOCK_MONOTONIC. Since the | |
90 | monotonic clock begins new with every reboot it only | |
91 | defines a well-defined point in time when used | |
b59866ae | 92 | together with an identifier identifying the boot, see |
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93 | <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
94 | for more information. If the boot ID parameter is | |
95 | passed NULL the function will fail if the monotonic | |
96 | timestamp of the current entry is not of the current | |
97 | system boot.</para> | |
98 | ||
99 | <para>Note that these functions will not work before | |
100 | <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
101 | (or related call) has been called at least | |
4a010f4e | 102 | once, in order to position the read pointer at a valid entry.</para> |
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103 | </refsect1> |
104 | ||
105 | <refsect1> | |
106 | <title>Return Value</title> | |
107 | ||
108 | <para><function>sd_journal_get_realtime_usec()</function> | |
109 | and | |
110 | <function>sd_journal_get_monotonic_usec()</function> | |
111 | returns 0 on success or a negative errno-style error | |
112 | code. If the boot ID parameter was passed NULL and the | |
113 | monotonic timestamp of the current journal entry is | |
114 | not of the current system boot, -ESTALE is returned by <function>sd_journal_get_monotonic_usec()</function>.</para> | |
115 | </refsect1> | |
116 | ||
117 | <refsect1> | |
118 | <title>Notes</title> | |
119 | ||
120 | <para>The | |
121 | <function>sd_journal_get_realtime_usec()</function> | |
122 | and | |
123 | <function>sd_journal_get_monotonic_usec()</function> | |
124 | interfaces are available as shared library, which can | |
125 | be compiled and linked to with the | |
126 | <literal>libsystemd-journal</literal> | |
127 | <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
128 | file.</para> | |
129 | </refsect1> | |
130 | ||
131 | <refsect1> | |
132 | <title>See Also</title> | |
133 | ||
134 | <para> | |
135 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
136 | <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
137 | <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
138 | <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
139 | <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
140 | <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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141 | <citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>, |
142 | <citerefentry><refentrytitle>sd_journal_get_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
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143 | </para> |
144 | </refsect1> | |
145 | ||
146 | </refentry> |