mirror of
https://github.com/systemd/systemd
synced 2024-07-05 17:39:42 +00:00
122 lines
5.1 KiB
XML
122 lines
5.1 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
|
|
<refentry id="sd_journal_get_cursor" xmlns:xi="http://www.w3.org/2001/XInclude">
|
|
|
|
<refentryinfo>
|
|
<title>sd_journal_get_cursor</title>
|
|
<productname>systemd</productname>
|
|
</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 project='man-pages'><refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
and should be freed after use with
|
|
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</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 sought to was actually found
|
|
in the journal or the next closest entry was used
|
|
instead.</para>
|
|
|
|
<para>Note that <function>sd_journal_get_cursor()</function>
|
|
and <function>sd_journal_test_cursor()</function>
|
|
will not work before
|
|
<citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
(or one of the other functions which move to an entry)
|
|
has been called at least once to position the read pointer at a valid entry.</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 does not
|
|
match the specified cursor or a negative errno-style error code on
|
|
failure.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Notes</title>
|
|
|
|
<xi:include href="threads-aware.xml" xpointer="strict" />
|
|
|
|
<xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>History</title>
|
|
<para><function>sd_journal_get_cursor()</function> was added in version 187.</para>
|
|
<para><function>sd_journal_test_cursor()</function> was added in version 195.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
|
|
<para><simplelist type="inline">
|
|
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
|
|
<member><citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
|
|
<member><citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
|
|
<member><citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
|
|
</simplelist></para>
|
|
</refsect1>
|
|
|
|
</refentry>
|