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Diffstat (limited to 'src/libsystemd/sd_journal_seek_head.xml')
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diff --git a/src/libsystemd/sd_journal_seek_head.xml b/src/libsystemd/sd_journal_seek_head.xml new file mode 100644 index 0000000000..985073496c --- /dev/null +++ b/src/libsystemd/sd_journal_seek_head.xml @@ -0,0 +1,175 @@ +<?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_seek_head"> + + <refentryinfo> + <title>sd_journal_seek_head</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_seek_head</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_journal_seek_head</refname> + <refname>sd_journal_seek_tail</refname> + <refname>sd_journal_seek_monotonic_usec</refname> + <refname>sd_journal_seek_realtime_usec</refname> + <refname>sd_journal_seek_cursor</refname> + <refpurpose>Seek to a position in the + journal</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_journal_seek_head</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_seek_tail</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_seek_monotonic_usec</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>sd_id128_t <parameter>boot_id</parameter></paramdef> + <paramdef>uint64_t <parameter>usec</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_seek_realtime_usec</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>uint64_t <parameter>usec</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_seek_cursor</function></funcdef> + <paramdef>sd_journal *<parameter>j</parameter></paramdef> + <paramdef>const char *<parameter>cursor</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_journal_seek_head()</function> seeks to the + beginning of the journal, i.e. the oldest available entry.</para> + + <para>Similarly, <function>sd_journal_seek_tail()</function> may + be used to seek to the end of the journal, i.e. the most recent + available entry.</para> + + <para><function>sd_journal_seek_monotonic_usec()</function> seeks + to the entry with the specified monotonic timestamp, i.e. + <constant>CLOCK_MONOTONIC</constant>. Since monotonic time + restarts on every reboot a boot ID needs to be specified as + well.</para> + + <para><function>sd_journal_seek_realtime_usec()</function> seeks + to the entry with the specified realtime (wallclock) timestamp, + i.e. <constant>CLOCK_REALTIME</constant>. Note that the realtime + clock is not necessarily monotonic. If a realtime timestamp is + ambiguous, it is not defined which position is sought to.</para> + + <para><function>sd_journal_seek_cursor()</function> seeks to the + entry located at the specified cursor string. For details on + cursors, see + <citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + If no entry matching the specified cursor is found the call will + seek to the next closest entry (in terms of time) instead. To + verify whether the newly selected entry actually matches the + cursor, use + <citerefentry><refentrytitle>sd_journal_test_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> + + <para>Note that these calls do not actually make any entry the new + current entry, this needs to be done in a separate step with a + subsequent + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> + invocation (or a similar call). Only then, entry data may be + retrieved via + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + If no entry exists that matches exactly the specified seek + address, the next closest is sought to. If + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> + is used, the closest following entry will be sought to, if + <citerefentry><refentrytitle>sd_journal_previous</refentrytitle><manvolnum>3</manvolnum></citerefentry> + is used the closest preceding entry is sought to.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The functions return 0 on success or a negative errno-style + error code.</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_seek_head()</function>, + <function>sd_journal_seek_tail()</function>, + <function>sd_journal_seek_monotonic_usec()</function>, + <function>sd_journal_seek_realtime_usec()</function>, + and <function>sd_journal_seek_cursor()</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_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_journal_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |