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diff --git a/man/sd_journal_get_cursor.xml b/man/sd_journal_get_cursor.xml new file mode 100644 index 0000000000..354168bee2 --- /dev/null +++ b/man/sd_journal_get_cursor.xml @@ -0,0 +1,151 @@ +<?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_cursor"> + + <refentryinfo> + <title>sd_journal_get_cursor</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_cursor</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_journal_get_cursor</refname> + <refname>sd_journal_test_cursor</refname> + <refpurpose>Get cursor string for or test cursor string against the current journal entry</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-journal.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_journal_get_cursor</function></funcdef> + <paramdef>sd_journal* <parameter>j</parameter></paramdef> + <paramdef>char ** <parameter>cursor</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_journal_test_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_get_cursor()</function> + returns a cursor string for the current journal + entry. A cursor is a serialization of the current + journal position formatted as text. The string only + contains printable characters and can be passed around + in text form. The cursor identifies a journal entry + globally and in a stable way and may be used to later + seek to it via + <citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The + cursor string should be considered opaque and not be + parsed by clients. Seeking to a cursor position + without the specific entry being available locally + will seek to the next closest (in terms of time) + available entry. The call takes two arguments: a + journal context object and a pointer to a string + pointer where the cursor string will be placed. The + string is allocated via libc + <citerefentry><refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum></citerefentry> + and should be freed after use with + <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> + + <para>Note that + <function>sd_journal_get_cursor()</function> will not + work before + <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry> + (or related call) has been called at least once, in + order to position the read pointer at a valid + entry.</para> + + <para><function>sd_journal_test_cursor()</function> + may be used to check whether the current position in + the journal matches the specified cursor. This is + useful since cursor strings do not uniquely identify + an entry: the same entry might be referred to by + multiple different cursor strings, and hence string + comparing cursors is not possible. Use this call to + verify after an invocation of + <citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry> + whether the entry being seeked to was actually found + in the journal or the next closest entry was used + instead.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>sd_journal_get_cursor()</function> + returns 0 on success or a negative errno-style error + code. <function>sd_journal_test_cursor()</function> + returns positive if the current entry matches the + specified cursor, 0 if it doesn't match the specified + cursor or a negative errno-style error code on + failure.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para>The <function>sd_journal_get_cursor()</function> + and <function>sd_journal_test_cursor()</function> + interfaces are available as shared library, which can + be compiled and linked to with the + <literal>libsystemd-journal</literal> + <citerefentry><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_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |