1<?xml version='1.0'?> <!--*-nxml-*--> 2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" 3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> 4<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> 5 6<refentry id="sd_journal_get_realtime_usec" 7 xmlns:xi="http://www.w3.org/2001/XInclude"> 8 9 <refentryinfo> 10 <title>sd_journal_get_realtime_usec</title> 11 <productname>systemd</productname> 12 </refentryinfo> 13 14 <refmeta> 15 <refentrytitle>sd_journal_get_realtime_usec</refentrytitle> 16 <manvolnum>3</manvolnum> 17 </refmeta> 18 19 <refnamediv> 20 <refname>sd_journal_get_realtime_usec</refname> 21 <refname>sd_journal_get_monotonic_usec</refname> 22 <refpurpose>Read timestamps from the current journal entry</refpurpose> 23 </refnamediv> 24 25 <refsynopsisdiv> 26 <funcsynopsis> 27 <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> 28 29 <funcprototype> 30 <funcdef>int <function>sd_journal_get_realtime_usec</function></funcdef> 31 <paramdef>sd_journal *<parameter>j</parameter></paramdef> 32 <paramdef>uint64_t *<parameter>usec</parameter></paramdef> 33 </funcprototype> 34 35 <funcprototype> 36 <funcdef>int <function>sd_journal_get_monotonic_usec</function></funcdef> 37 <paramdef>sd_journal *<parameter>j</parameter></paramdef> 38 <paramdef>uint64_t *<parameter>usec</parameter></paramdef> 39 <paramdef>sd_id128_t *<parameter>boot_id</parameter></paramdef> 40 </funcprototype> 41 42 </funcsynopsis> 43 </refsynopsisdiv> 44 45 <refsect1> 46 <title>Description</title> 47 48 <para><function>sd_journal_get_realtime_usec()</function> gets the 49 realtime (wallclock) timestamp of the current journal entry. It 50 takes two arguments: the journal context object and a pointer to a 51 64-bit unsigned integer to store the timestamp in. The timestamp 52 is in microseconds since the epoch, i.e. 53 <constant>CLOCK_REALTIME</constant>.</para> 54 55 <para><function>sd_journal_get_monotonic_usec()</function> gets 56 the monotonic timestamp of the current journal entry. It takes 57 three arguments: the journal context object, a pointer to a 64-bit 58 unsigned integer to store the timestamp in, as well as a 128-bit 59 ID buffer to store the boot ID of the monotonic timestamp. The 60 timestamp is in microseconds since boot-up of the specific boot, 61 i.e. <constant>CLOCK_MONOTONIC</constant>. Since the monotonic 62 clock begins new with every reboot, it only defines a well-defined 63 point in time when used together with an identifier identifying 64 the boot. See 65 <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry> 66 for more information. If the boot ID parameter is passed 67 <constant>NULL</constant>, the function will fail if the monotonic 68 timestamp of the current entry is not of the current system 69 boot.</para> 70 71 <para>Note that these functions will not work before 72 <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> 73 (or related call) has been called at least 74 once, in order to position the read pointer at a valid entry.</para> 75 </refsect1> 76 77 <refsect1> 78 <title>Return Value</title> 79 80 <para><function>sd_journal_get_realtime_usec()</function> and 81 <function>sd_journal_get_monotonic_usec()</function> returns 0 on 82 success or a negative errno-style error code. If the boot ID 83 parameter was passed <constant>NULL</constant> and the monotonic 84 timestamp of the current journal entry is not of the current 85 system boot, <constant>-ESTALE</constant> is returned by 86 <function>sd_journal_get_monotonic_usec()</function>.</para> 87 </refsect1> 88 89 <refsect1> 90 <title>Notes</title> 91 92 <xi:include href="threads-aware.xml" xpointer="strict"/> 93 94 <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/> 95 </refsect1> 96 97 <refsect1> 98 <title>See Also</title> 99 100 <para> 101 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, 102 <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, 103 <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>, 104 <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>, 105 <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, 106 <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>, 107 <citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>, 108 <citerefentry><refentrytitle>sd_journal_get_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry> 109 </para> 110 </refsect1> 111 112</refentry> 113