+++ /dev/null
-<?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_open">
-
- <refentryinfo>
- <title>sd_journal_open</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_open</refentrytitle>
- <manvolnum>3</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>sd_journal_open</refname>
- <refname>sd_journal_open_directory</refname>
- <refname>sd_journal_open_files</refname>
- <refname>sd_journal_open_container</refname>
- <refname>sd_journal_close</refname>
- <refname>sd_journal</refname>
- <refname>SD_JOURNAL_LOCAL_ONLY</refname>
- <refname>SD_JOURNAL_RUNTIME_ONLY</refname>
- <refname>SD_JOURNAL_SYSTEM</refname>
- <refname>SD_JOURNAL_CURRENT_USER</refname>
- <refpurpose>Open the system journal for reading</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo>
-
- <funcprototype>
- <funcdef>int <function>sd_journal_open</function></funcdef>
- <paramdef>sd_journal **<parameter>ret</parameter></paramdef>
- <paramdef>int <parameter>flags</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>int <function>sd_journal_open_directory</function></funcdef>
- <paramdef>sd_journal **<parameter>ret</parameter></paramdef>
- <paramdef>const char *<parameter>path</parameter></paramdef>
- <paramdef>int <parameter>flags</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>int <function>sd_journal_open_files</function></funcdef>
- <paramdef>sd_journal **<parameter>ret</parameter></paramdef>
- <paramdef>const char **<parameter>paths</parameter></paramdef>
- <paramdef>int <parameter>flags</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>int <function>sd_journal_open_container</function></funcdef>
- <paramdef>sd_journal **<parameter>ret</parameter></paramdef>
- <paramdef>const char *<parameter>machine</parameter></paramdef>
- <paramdef>int <parameter>flags</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>void <function>sd_journal_close</function></funcdef>
- <paramdef>sd_journal *<parameter>j</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para><function>sd_journal_open()</function> opens the log journal
- for reading. It will find all journal files automatically and
- interleave them automatically when reading. As first argument it
- takes a pointer to a <varname>sd_journal</varname> pointer, which
- on success will contain a journal context object. The second
- argument is a flags field, which may consist of the following
- flags ORed together: <constant>SD_JOURNAL_LOCAL_ONLY</constant>
- makes sure only journal files generated on the local machine will
- be opened. <constant>SD_JOURNAL_RUNTIME_ONLY</constant> makes sure
- only volatile journal files will be opened, excluding those which
- are stored on persistent storage.
- <constant>SD_JOURNAL_SYSTEM</constant> will cause journal files of
- system services and the kernel (in opposition to user session
- processes) to be opened.
- <constant>SD_JOURNAL_CURRENT_USER</constant> will cause journal
- files of the current user to be opened. If neither
- <constant>SD_JOURNAL_SYSTEM</constant> nor
- <constant>SD_JOURNAL_CURRENT_USER</constant> are specified, all
- journal file types will be opened.</para>
-
- <para><function>sd_journal_open_directory()</function> is similar
- to <function>sd_journal_open()</function> but takes an absolute
- directory path as argument. All journal files in this directory
- will be opened and interleaved automatically. This call also takes
- a flags argument, but it must be passed as 0 as no flags are
- currently understood for this call.</para>
-
- <para><function>sd_journal_open_files()</function> is similar to
- <function>sd_journal_open()</function> but takes a
- <constant>NULL</constant>-terminated list of file paths to open.
- All files will be opened and interleaved automatically. This call
- also takes a flags argument, but it must be passed as 0 as no
- flags are currently understood for this call. Please note that in
- the case of a live journal, this function is only useful for
- debugging, because individual journal files can be rotated at any
- moment, and the opening of specific files is inherently
- racy.</para>
-
- <para><function>sd_journal_open_container()</function> is similar
- to <function>sd_journal_open()</function> but opens the journal
- files of a running OS container. The specified machine name refers
- to a container that is registered with
- <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
- <para><varname>sd_journal</varname> objects cannot be used in the
- child after a fork. Functions which take a journal object as an
- argument (<function>sd_journal_next()</function> and others) will
- return <constant>-ECHILD</constant> after a fork.
- </para>
-
- <para><function>sd_journal_close()</function> will close the
- journal context allocated with
- <function>sd_journal_open()</function> or
- <function>sd_journal_open_directory()</function> and free its
- resources.</para>
-
- <para>When opening the journal only journal files accessible to
- the calling user will be opened. If journal files are not
- accessible to the caller, this will be silently ignored.</para>
-
- <para>See
- <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for an example of how to iterate through the journal after opening
- it with <function>sd_journal_open()</function>.</para>
-
- <para>A journal context object returned by
- <function>sd_journal_open()</function> references a specific
- journal entry as <emphasis>current</emphasis> entry, similar to a
- file seek index in a classic file system file, but without
- absolute positions. It may be altered with
- <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- and
- <citerefentry><refentrytitle>sd_journal_seek_head</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- and related calls. The current entry position may be exported in
- <emphasis>cursor</emphasis> strings, as accessible via
- <citerefentry><refentrytitle>sd_journal_get_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- Cursor strings may be used to globally identify a specific journal
- entry in a stable way and then later to seek to it (or if the
- specific entry is not available locally, to its closest entry in
- time)
- <citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
-
- <para>Notification of journal changes is available via
- <function>sd_journal_get_fd()</function> and related calls.</para>
- </refsect1>
-
- <refsect1>
- <title>Return Value</title>
-
- <para>The <function>sd_journal_open()</function>,
- <function>sd_journal_open_directory()</function>, and
- <function>sd_journal_open_files()</function> calls return 0 on
- success or a negative errno-style error code.
- <function>sd_journal_close()</function> returns nothing.</para>
- </refsect1>
-
- <refsect1>
- <title>Notes</title>
-
- <para>The <function>sd_journal_open()</function>,
- <function>sd_journal_open_directory()</function> and
- <function>sd_journal_close()</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>History</title>
-
- <para><function>sd_journal_open()</function>,
- <function>sd_journal_close()</function>,
- <constant>SD_JOURNAL_LOCAL_ONLY</constant>,
- <constant>SD_JOURNAL_RUNTIME_ONLY</constant>,
- <constant>SD_JOURNAL_SYSTEM_ONLY</constant> were added in
- systemd-38.</para>
-
- <para><function>sd_journal_open_directory()</function> was added
- in systemd-187.</para>
-
- <para><constant>SD_JOURNAL_SYSTEM</constant>,
- <constant>SD_JOURNAL_CURRENT_USER</constant>, and
- <function>sd_journal_open_files()</function> were added in
- systemd-205. <constant>SD_JOURNAL_SYSTEM_ONLY</constant> was
- deprecated.</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_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>
~ianmdlvl / elogind.git / blobdiff