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11a1589223
Files which are installed as-is (any .service and other unit files, .conf files, .policy files, etc), are left as is. My assumption is that SPDX identifiers are not yet that well known, so it's better to retain the extended header to avoid any doubt. I also kept any copyright lines. We can probably remove them, but it'd nice to obtain explicit acks from all involved authors before doing that.
131 lines
5.2 KiB
XML
131 lines
5.2 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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-->
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<refentry id="sd_journal_get_realtime_usec">
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<refentryinfo>
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<title>sd_journal_get_realtime_usec</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_journal_get_realtime_usec</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_journal_get_realtime_usec</refname>
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<refname>sd_journal_get_monotonic_usec</refname>
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<refpurpose>Read timestamps from the current journal entry</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_journal_get_realtime_usec</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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<paramdef>uint64_t *<parameter>usec</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_journal_get_monotonic_usec</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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<paramdef>uint64_t *<parameter>usec</parameter></paramdef>
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<paramdef>sd_id128_t *<parameter>boot_id</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_journal_get_realtime_usec()</function> gets the
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realtime (wallclock) timestamp of the current journal entry. It
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takes two arguments: the journal context object and a pointer to a
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64-bit unsigned integer to store the timestamp in. The timestamp
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is in microseconds since the epoch, i.e.
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<constant>CLOCK_REALTIME</constant>.</para>
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<para><function>sd_journal_get_monotonic_usec()</function> gets
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the monotonic timestamp of the current journal entry. It takes
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three arguments: the journal context object, a pointer to a 64-bit
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unsigned integer to store the timestamp in, as well as a 128-bit
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ID buffer to store the boot ID of the monotonic timestamp. The
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timestamp is in microseconds since boot-up of the specific boot,
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i.e. <constant>CLOCK_MONOTONIC</constant>. Since the monotonic
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clock begins new with every reboot, it only defines a well-defined
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point in time when used together with an identifier identifying
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the boot. See
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<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for more information. If the boot ID parameter is passed
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<constant>NULL</constant>, the function will fail if the monotonic
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timestamp of the current entry is not of the current system
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boot.</para>
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<para>Note that these functions will not work before
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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(or related call) has been called at least
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once, in order to position the read pointer at a valid entry.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para><function>sd_journal_get_realtime_usec()</function> and
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<function>sd_journal_get_monotonic_usec()</function> returns 0 on
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success or a negative errno-style error code. If the boot ID
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parameter was passed <constant>NULL</constant> and the monotonic
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timestamp of the current journal entry is not of the current
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system boot, <constant>-ESTALE</constant> is returned by
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<function>sd_journal_get_monotonic_usec()</function>.</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>The <function>sd_journal_get_realtime_usec()</function> and
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<function>sd_journal_get_monotonic_usec()</function> interfaces
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are available as a shared library, which can be compiled and
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linked to with the
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<constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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