Adding upstream version 252.22.upstream/252.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 175 insertions, 0 deletions

diff --git a/man/sd_journal_query_unique.xml b/man/sd_journal_query_unique.xml
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+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
+
+<refentry id="sd_journal_query_unique" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>sd_journal_query_unique</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_journal_query_unique</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_journal_query_unique</refname>
+    <refname>sd_journal_enumerate_unique</refname>
+    <refname>sd_journal_enumerate_available_unique</refname>
+    <refname>sd_journal_restart_unique</refname>
+    <refname>SD_JOURNAL_FOREACH_UNIQUE</refname>
+    <refpurpose>Read unique data fields from the journal</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_journal_query_unique</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+        <paramdef>const char *<parameter>field</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_journal_enumerate_available_unique</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+        <paramdef>const void **<parameter>data</parameter></paramdef>
+        <paramdef>size_t *<parameter>length</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_journal_enumerate_unique</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+        <paramdef>const void **<parameter>data</parameter></paramdef>
+        <paramdef>size_t *<parameter>length</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>void <function>sd_journal_restart_unique</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef><function>SD_JOURNAL_FOREACH_UNIQUE</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+        <paramdef>const void *<parameter>data</parameter></paramdef>
+        <paramdef>size_t <parameter>length</parameter></paramdef>
+      </funcprototype>
+
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_journal_query_unique()</function> queries the journal for all unique values the
+    specified field can take. It takes two arguments: the journal to query and the field name to look
+    for. Well-known field names are listed on
+    <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+    but any field can be specified. Field names must be specified without a trailing
+    <literal>=</literal>. After this function has been executed successfully the field values may be queried
+    using <function>sd_journal_enumerate_unique()</function> and
+    <function>sd_journal_enumerate_available_unique()</function>. Invoking one of those calls will change the
+    field name being queried and reset the enumeration index to the first field value that matches.</para>
+
+    <para><function>sd_journal_enumerate_unique()</function> may be used to iterate through all data fields
+    which match the previously selected field name as set with
+    <function>sd_journal_query_unique()</function>. On each invocation the next field data matching the field
+    name is returned. The order of the returned data fields is not defined. It takes three arguments: the
+    journal object, plus a pair of pointers to pointer/size variables where the data object and its size
+    shall be stored. The returned data is in a read-only memory map and is only valid until the next
+    invocation of <function>sd_journal_enumerate_unique()</function>. Note that the data returned will be
+    prefixed with the field name and <literal>=</literal>. Note that this call is subject to the data field
+    size threshold as controlled by <function>sd_journal_set_data_threshold()</function> and only the initial
+    part of the field up to the threshold is returned. An error is returned for fields which cannot be
+    retrieved. See the error list below for details.</para>
+
+    <para><function>sd_journal_enumerate_available_unique()</function> is similar to
+    <function>sd_journal_enumerate_unique()</function>, but silently skips any fields which may be valid, but
+    are too large or not supported by current implementation.</para>
+
+    <para><function>sd_journal_restart_unique()</function> resets the
+    data enumeration index to the beginning of the list. The next
+    invocation of <function>sd_journal_enumerate_unique()</function>
+    will return the first field data matching the field name
+    again.</para>
+
+    <para>Note that the <function>SD_JOURNAL_FOREACH_UNIQUE()</function> macro may be used as a handy wrapper
+    around <function>sd_journal_restart_unique()</function> and
+    <function>sd_journal_enumerate_available_unique()</function>.</para>
+
+    <para>Note that these functions currently are not influenced by
+    matches set with <function>sd_journal_add_match()</function> but
+    this might change in a later version of this software.</para>
+
+    <para>To enumerate all field names currently in use (and thus all suitable field parameters for
+    <function>sd_journal_query_unique()</function>), use the
+    <citerefentry><refentrytitle>sd_journal_enumerate_fields</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    call.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para><function>sd_journal_query_unique()</function> returns 0 on success or a negative errno-style error
+    code. <function>sd_journal_enumerate_unique()</function> and
+    <function>sd_journal_query_available_unique()</function> return a positive integer if the next field data
+    has been read, 0 when no more fields remain, or a negative errno-style error code.
+    <function>sd_journal_restart_unique()</function> doesn't return anything.</para>
+
+    <refsect2>
+      <title>Errors</title>
+
+      <para>Returned errors may indicate the following problems:</para>
+
+      <variablelist>
+        <xi:include href="sd_journal_get_data.xml" xpointer="EINVAL"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="ECHILD"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="EADDRNOTAVAIL"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="ENOENT"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="ENOBUFS"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="E2BIG"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="EPROTONOSUPPORT"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="EBADMSG"/>
+        <xi:include href="sd_journal_get_data.xml" xpointer="EIO"/>
+      </variablelist>
+    </refsect2>
+  </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>Examples</title>
+
+    <para>Use the <function>SD_JOURNAL_FOREACH_UNIQUE()</function> macro to iterate through all values a field
+    of the journal can take (and which can be accessed on the given architecture and are not compressed with
+    an unsupported mechanism). The following example lists all unit names referenced in the journal:</para>
+
+    <programlisting><xi:include href="journal-iterate-unique.c" parse="text" /></programlisting>
+  </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_enumerate_fields</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_journal_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_journal_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>