man/sd_journal_get_cursor.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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  23
  24 <refentry id="sd_journal_get_cursor">
  25
  26         <refentryinfo>
  27                 <title>sd_journal_get_cursor</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>sd_journal_get_cursor</refentrytitle>
  42                 <manvolnum>3</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>sd_journal_get_cursor</refname>
  47                 <refpurpose>Get cursor string for the current journal entry</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <funcsynopsis>
  52                         <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
  53
  54                         <funcprototype>
  55                                 <funcdef>int <function>sd_journal_get_cursor</function></funcdef>
  56                                 <paramdef>sd_journal* <parameter>j</parameter></paramdef>
  57                                 <paramdef>char ** <parameter>cursor</parameter></paramdef>
  58                         </funcprototype>
  59
  60                 </funcsynopsis>
  61         </refsynopsisdiv>
  62
  63         <refsect1>
  64                 <title>Description</title>
  65
  66                 <para><function>sd_journal_get_cursor()</function>
  67                 returns a cursor string for the current journal
  68                 entry. A cursor is a serialization of the current
  69                 journal position in text form. The string only
  70                 contains printable characters and can be passed around
  71                 in text form. The cursor identifies a journal entry
  72                 globally and in a stable way and may be used to later
  73                 seek to it via
  74                 <citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The
  75                 cursor string should be considered opaque and not be
  76                 parsed by clients. Seeking to a cursor position
  77                 without the specific entry being available locally
  78                 will seek to the next closest (in terms of time)
  79                 available entry. The call takes two arguments: a
  80                 journal context object and a pointer to a
  81                 string pointer where the cursor string will be
  82                 placed. The string is allocated via libc <citerefentry><refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum></citerefentry> and should
  83                 be freed after use with
  84                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  85
  86                 <para>Note that this function will not work before
  87                 <citerefentry><refentrytitle>sd_journal_next</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  88                 (or related call) has been called at least
  89                 once, in order to position the read pointer at a valid entry.</para>
  90         </refsect1>
  91
  92         <refsect1>
  93                 <title>Return Value</title>
  94
  95                 <para><function>sd_journal_get_cursor()</function>
  96                 returns 0 on success or a negative errno-style error
  97                 code.</para>
  98         </refsect1>
  99
 100         <refsect1>
 101                 <title>Notes</title>
 102
 103                 <para>The <function>sd_journal_get_cursor()</function>
 104                 interface is available as shared library, which can be
 105                 compiled and linked to with the
 106                 <literal>libsystemd-journal</literal>
 107                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 108                 file.</para>
 109         </refsect1>
 110
 111         <refsect1>
 112                 <title>See Also</title>
 113
 114                 <para>
 115                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 116                         <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 117                         <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 118                         <citerefentry><refentrytitle>sd_journal_seek_cursor</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 119                 </para>
 120         </refsect1>
 121
 122 </refentry>