systemd/man/sd_journal_get_cutoff_realtime_usec.xml
2016-10-15 18:38:20 -04:00

149 lines
6.2 KiB
XML
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<?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_journal_get_cutoff_realtime_usec">
<refentryinfo>
<title>sd_journal_get_cutoff_realtime_usec</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_journal_get_cutoff_realtime_usec</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_journal_get_cutoff_realtime_usec</refname>
<refname>sd_journal_get_cutoff_monotonic_usec</refname>
<refpurpose>Read cut-off timestamps from the current journal entry</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_journal_get_cutoff_realtime_usec</function></funcdef>
<paramdef>sd_journal *<parameter>j</parameter></paramdef>
<paramdef>uint64_t *<parameter>from</parameter></paramdef>
<paramdef>uint64_t *<parameter>to</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_journal_get_cutoff_monotonic_usec</function></funcdef>
<paramdef>sd_journal *<parameter>j</parameter></paramdef>
<paramdef>sd_id128_t <parameter>boot_id</parameter></paramdef>
<paramdef>uint64_t *<parameter>from</parameter></paramdef>
<paramdef>uint64_t *<parameter>to</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_journal_get_cutoff_realtime_usec()</function>
retrieves the realtime (wallclock) timestamps of the first and
last entries accessible in the journal. It takes three arguments:
the journal context object <parameter>j</parameter> and two
pointers <parameter>from</parameter> and <parameter>to</parameter>
pointing at 64-bit unsigned integers to store the timestamps in.
The timestamps are in microseconds since the epoch, i.e.
<constant>CLOCK_REALTIME</constant>. Either one of the two
timestamp arguments may be passed as <constant>NULL</constant> in
case the timestamp is not needed, but not both.</para>
<para><function>sd_journal_get_cutoff_monotonic_usec()</function>
retrieves the monotonic timestamps of the first and last entries
accessible in the journal. It takes three arguments: the journal
context object <parameter>j</parameter>, a 128-bit identifier for
the boot <parameter>boot_id</parameter>, and two pointers to
64-bit unsigned integers to store the timestamps,
<parameter>from</parameter> and <parameter>to</parameter>. The
timestamps are in microseconds since boot-up of the specific boot,
i.e. <constant>CLOCK_MONOTONIC</constant>. Since the monotonic
clock begins new with every reboot it only defines a well-defined
point in time when used together with an identifier identifying
the boot, see
<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for more information. The function will return the timestamps for
the boot identified by the passed boot ID. Either one of the two
timestamp arguments may be passed as <constant>NULL</constant> in
case the timestamp is not needed, but not both.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>sd_journal_get_cutoff_realtime_usec()</function>
and <function>sd_journal_get_cutoff_monotonic_usec()</function>
return 1 on success, 0 if not suitable entries are in the journal
or a negative errno-style error code.</para>
<para>Locations pointed to by parameters
<parameter>from</parameter> and <parameter>to</parameter> will be
set only if the return value is positive, and obviously, the
parameters are non-null.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>All functions listed here are thread-agnostic and only a single thread may operate
on a given <structname>sd_journal</structname> object.</para>
<para>The
<function>sd_journal_get_cutoff_realtime_usec()</function> and
<function>sd_journal_get_cutoff_monotonic_usec()</function>
interfaces are available as a shared library, which can be
compiled and linked to with the
<constant>libsystemd</constant> <citerefentry project='die-net'><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-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>