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The only difference is that functions are not individually listed by name, but that seems completely pointless, since all functions that are documented are always exported, so the generic text tells the user all she or he needs to know.
157 lines
6.2 KiB
XML
157 lines
6.2 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_seek_head" xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo>
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<title>sd_journal_seek_head</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_seek_head</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_seek_head</refname>
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<refname>sd_journal_seek_tail</refname>
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<refname>sd_journal_seek_monotonic_usec</refname>
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<refname>sd_journal_seek_realtime_usec</refname>
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<refname>sd_journal_seek_cursor</refname>
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<refpurpose>Seek to a position in the
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journal</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_seek_head</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_journal_seek_tail</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_journal_seek_monotonic_usec</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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<paramdef>sd_id128_t <parameter>boot_id</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_seek_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_seek_cursor</function></funcdef>
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<paramdef>sd_journal *<parameter>j</parameter></paramdef>
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<paramdef>const char *<parameter>cursor</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_seek_head()</function> seeks to the
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beginning of the journal, i.e. the oldest available entry.</para>
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<para>Similarly, <function>sd_journal_seek_tail()</function> may
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be used to seek to the end of the journal, i.e. the most recent
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available entry.</para>
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<para><function>sd_journal_seek_monotonic_usec()</function> seeks
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to the entry with the specified monotonic timestamp, i.e.
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<constant>CLOCK_MONOTONIC</constant>. Since monotonic time
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restarts on every reboot a boot ID needs to be specified as
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well.</para>
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<para><function>sd_journal_seek_realtime_usec()</function> seeks
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to the entry with the specified realtime (wallclock) timestamp,
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i.e. <constant>CLOCK_REALTIME</constant>. Note that the realtime
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clock is not necessarily monotonic. If a realtime timestamp is
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ambiguous, it is not defined which position is sought to.</para>
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<para><function>sd_journal_seek_cursor()</function> seeks to the
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entry located at the specified cursor string. For details on
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cursors, see
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<citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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If no entry matching the specified cursor is found the call will
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seek to the next closest entry (in terms of time) instead. To
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verify whether the newly selected entry actually matches the
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cursor, use
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<citerefentry><refentrytitle>sd_journal_test_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
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<para>Note that these calls do not actually make any entry the new
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current entry, this needs to be done in a separate step with a
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subsequent
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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invocation (or a similar call). Only then, entry data may be
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retrieved via
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<citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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If no entry exists that matches exactly the specified seek
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address, the next closest is sought to. If
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<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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is used, the closest following entry will be sought to, if
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<citerefentry><refentrytitle>sd_journal_previous</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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is used the closest preceding entry is sought to.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>The functions return 0 on success or a negative errno-style
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error code.</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>All functions listed here are thread-agnostic and only a single thread may operate
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on a given <structname>sd_journal</structname> object.</para>
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<xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
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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_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_journal_get_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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