man/sd_journal_get_cutoff_realtime_usec.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 <!ENTITY % entities SYSTEM "custom-entities.ent" >
   5 %entities;
   6 ]>
   7
   8 <!--
   9   This file is part of systemd.
  10
  11   Copyright 2012 Lennart Poettering
  12
  13   systemd is free software; you can redistribute it and/or modify it
  14   under the terms of the GNU Lesser General Public License as published by
  15   the Free Software Foundation; either version 2.1 of the License, or
  16   (at your option) any later version.
  17
  18   systemd is distributed in the hope that it will be useful, but
  19   WITHOUT ANY WARRANTY; without even the implied warranty of
  20   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  21   Lesser General Public License for more details.
  22
  23   You should have received a copy of the GNU Lesser General Public License
  24   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  25 -->
  26
  27 <refentry id="sd_journal_get_cutoff_realtime_usec">
  28
  29   <refentryinfo>
  30     <title>sd_journal_get_cutoff_realtime_usec</title>
  31     <productname>systemd</productname>
  32
  33     <authorgroup>
  34       <author>
  35         <contrib>Developer</contrib>
  36         <firstname>Lennart</firstname>
  37         <surname>Poettering</surname>
  38         <email>lennart@poettering.net</email>
  39       </author>
  40     </authorgroup>
  41   </refentryinfo>
  42
  43   <refmeta>
  44     <refentrytitle>sd_journal_get_cutoff_realtime_usec</refentrytitle>
  45     <manvolnum>3</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>sd_journal_get_cutoff_realtime_usec</refname>
  50     <refname>sd_journal_get_cutoff_monotonic_usec</refname>
  51     <refpurpose>Read cut-off timestamps from the current journal entry</refpurpose>
  52   </refnamediv>
  53
  54   <refsynopsisdiv>
  55     <funcsynopsis>
  56       <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
  57
  58       <funcprototype>
  59         <funcdef>int <function>sd_journal_get_cutoff_realtime_usec</function></funcdef>
  60         <paramdef>sd_journal *<parameter>j</parameter></paramdef>
  61         <paramdef>uint64_t *<parameter>from</parameter></paramdef>
  62         <paramdef>uint64_t *<parameter>to</parameter></paramdef>
  63       </funcprototype>
  64
  65       <funcprototype>
  66         <funcdef>int <function>sd_journal_get_cutoff_monotonic_usec</function></funcdef>
  67         <paramdef>sd_journal *<parameter>j</parameter></paramdef>
  68         <paramdef>sd_id128_t <parameter>boot_id</parameter></paramdef>
  69         <paramdef>uint64_t *<parameter>from</parameter></paramdef>
  70         <paramdef>uint64_t *<parameter>to</parameter></paramdef>
  71       </funcprototype>
  72
  73     </funcsynopsis>
  74   </refsynopsisdiv>
  75
  76   <refsect1>
  77     <title>Description</title>
  78
  79     <para><function>sd_journal_get_cutoff_realtime_usec()</function>
  80     retrieves the realtime (wallclock) timestamps of the first and
  81     last entries accessible in the journal. It takes three arguments:
  82     the journal context object <parameter>j</parameter> and two
  83     pointers <parameter>from</parameter> and <parameter>to</parameter>
  84     pointing at 64-bit unsigned integers to store the timestamps in.
  85     The timestamps are in microseconds since the epoch, i.e.
  86     <constant>CLOCK_REALTIME</constant>. Either one of the two
  87     timestamp arguments may be passed as <constant>NULL</constant> in
  88     case the timestamp is not needed, but not both.</para>
  89
  90     <para><function>sd_journal_get_cutoff_monotonic_usec()</function>
  91     retrieves the monotonic timestamps of the first and last entries
  92     accessible in the journal. It takes three arguments: the journal
  93     context object <parameter>j</parameter>, a 128-bit identifier for
  94     the boot <parameter>boot_id</parameter>, and two pointers to
  95     64-bit unsigned integers to store the timestamps,
  96     <parameter>from</parameter> and <parameter>to</parameter>. The
  97     timestamps are in microseconds since boot-up of the specific boot,
  98     i.e. <constant>CLOCK_MONOTONIC</constant>. Since the monotonic
  99     clock begins new with every reboot it only defines a well-defined
 100     point in time when used together with an identifier identifying
 101     the boot, see
 102     <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 103     for more information. The function will return the timestamps for
 104     the boot identified by the passed boot ID. Either one of the two
 105     timestamp arguments may be passed as <constant>NULL</constant> in
 106     case the timestamp is not needed, but not both.</para>
 107   </refsect1>
 108
 109   <refsect1>
 110     <title>Return Value</title>
 111
 112     <para><function>sd_journal_get_cutoff_realtime_usec()</function>
 113     and <function>sd_journal_get_cutoff_monotonic_usec()</function>
 114     return 1 on success, 0 if not suitable entries are in the journal
 115     or a negative errno-style error code.</para>
 116
 117     <para>Locations pointed to by parameters
 118     <parameter>from</parameter> and <parameter>to</parameter> will be
 119     set only if the return value is positive, and obviously, the
 120     parameters are non-null.</para>
 121   </refsect1>
 122
 123   <refsect1>
 124     <title>Notes</title>
 125
 126     <para>The
 127     <function>sd_journal_get_cutoff_realtime_usec()</function> and
 128     <function>sd_journal_get_cutoff_monotonic_usec()</function>
 129     interfaces are available as a shared library, which can be
 130     compiled and linked to with the
 131     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 132     file.</para>
 133   </refsect1>
 134
 135   <refsect1>
 136     <title>See Also</title>
 137
 138     <para>
 139       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 140       <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 141       <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 142       <citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 143       <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 144       <citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 145     </para>
 146   </refsect1>
 147
 148 </refentry>