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systemd/man/sd_journal_get_catalog.xml
Lennart Poettering 64a7ef8bc0 man: be more explicit about thread safety of sd_journal
Triggered by https://bugzilla.redhat.com/show_bug.cgi?id=1609349

This adds two generic paragaphs we include via xinclude. One is the
"strict" version, which contains wording saying that we are thread
agnostic and what that means. And the other is the "safe" version, for
the cases we provide fully safety.

Let's then change most man pages to use either of these generic
paragraphs. With one exception: man/sd_journal_get_catalog.xml contains
both kinds of function, we hence use manual wording.
2018-08-03 17:36:11 +02:00

117 lines
4.7 KiB
XML

<?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">
<!--
SPDX-License-Identifier: LGPL-2.1+
-->
<refentry id="sd_journal_get_catalog" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_journal_get_catalog</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_journal_get_catalog</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_journal_get_catalog</refname>
<refname>sd_journal_get_catalog_for_message_id</refname>
<refpurpose>Retrieve message catalog entry</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_journal_get_catalog</function></funcdef>
<paramdef>sd_journal *<parameter>j</parameter></paramdef>
<paramdef>char **<parameter>ret</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_journal_get_catalog_for_message_id</function></funcdef>
<paramdef>sd_id128_t <parameter>id</parameter></paramdef>
<paramdef>char **<parameter>ret</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_journal_get_catalog()</function> retrieves a
message catalog entry for the current journal entry. This will
look up an entry in the message catalog by using the
<literal>MESSAGE_ID=</literal> field of the current journal entry.
Before returning the entry all journal field names in the catalog
entry text enclosed in "@" will be replaced by the respective
field values of the current entry. If a field name referenced in
the message catalog entry does not exist, in the current journal
entry, the "@" will be removed, but the field name otherwise left
untouched.</para>
<para><function>sd_journal_get_catalog_for_message_id()</function>
works similar to <function>sd_journal_get_catalog()</function> but
the entry is looked up by the specified message ID (no open
journal context is necessary for this), and no field substitution
is performed.</para>
<para>For more information about the journal message catalog
please refer to the <ulink
url="https://www.freedesktop.org/wiki/Software/systemd/catalog">Journal
Message Catalogs</ulink> documentation page.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>sd_journal_get_catalog()</function> and
<function>sd_journal_get_catalog_for_message_id()</function>
return 0 on success or a negative errno-style error code. If no
matching message catalog entry is found, -ENOENT is
returned.</para>
<para>On successful return, <parameter>ret</parameter> points to a
new string, which must be freed with
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>Function <function>sd_journal_get_catalog()</function> is thread-agnostic and only
a single specific thread may operate on a given object during its entire lifetime. It's safe to allocate multiple
independent objects and use each from a specific thread in parallel. However, it's not safe to allocate such an
object in one thread, and operate or free it from any other, even if locking is used to ensure these threads don't
operate on it at the very same time.</para>
<para>Function <function>sd_journal_get_catalog_for_message_id()</function> is are thread-safe and may be called in
parallel from multiple threads.</para>
<xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</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 project='man-pages'><refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>