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authorAnthony G. Basile <blueness@gentoo.org>2012-11-15 10:33:16 -0500
committerAnthony G. Basile <blueness@gentoo.org>2012-11-15 10:33:16 -0500
commit7d4a62f8c1404ed426500b97af03d4ef8d034a71 (patch)
tree2436cd4f0460a3a3d589875d4ffba55556f3c582 /man/sd_journal_query_unique.xml
parent2944f347d087ff24ec808e4b70fe104a772a97a0 (diff)
Isolation of udev code from remaining systemd
This commit is a first attempt to isolate the udev code from the remaining code base. It intentionally does not modify any files but purely delete files which, on a first examination, appear to not be needed. This is a sweeping commit which may easily have missed needed code. Files can be retrieved by doing a checkout from the previous commit: git checkout 2944f347d0 -- <filename>
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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 V4.2//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_query_unique">
-
- <refentryinfo>
- <title>sd_journal_query_unique</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_query_unique</refentrytitle>
- <manvolnum>3</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>sd_journal_query_unique</refname>
- <refname>sd_journal_enumerate_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_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>. Field
- names must be specified without a trailing '='. After
- this function has been executed successfully the field
- values may be queried using
- <function>sd_journal_enumerate_unique()</function>. Invoking
- this call a second time 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 context object, plus a pair of pointers to
- pointer/size variables where the data object and its
- size shall be stored in. 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 '='.</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_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>
- </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>
- returns a positive integer if the next field data has
- been read, 0 when no more fields are known, or a
- negative errno-style error
- code. <function>sd_journal_restart_unique()</function>
- returns nothing.</para>
- </refsect1>
-
- <refsect1>
- <title>Notes</title>
-
- <para>The <function>sd_journal_query_unique()</function>,
- <function>sd_journal_enumerate_unique()</function> and
- <function>sd_journal_restart_unique()</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>Examples</title>
-
- <para>Use the
- <function>SD_JOURNAL_FOREACH_UNIQUE</function> macro
- to iterate through all values a field of the journal
- can take. The following example lists all unit names
- referenced in the journal:</para>
-
- <programlisting>#include &lt;stdio.h&gt;
-#include &lt;string.h&gt;
-#include &lt;systemd/sd-journal.h&gt;
-
-int main(int argc, char *argv[]) {
- sd_journal *j;
- const void *d;
- size_t l;
- int r;
-
- r = sd_journal_open(&amp;j, SD_JOURNAL_LOCAL_ONLY);
- if (r &lt; 0) {
- fprintf(stderr, "Failed to open journal: %s\n", strerror(-r));
- return 1;
- }
- r = sd_journal_query_unique(j, "_SYSTEMD_UNIT");
- if (r &lt; 0) {
- fprintf(stderr, "Failed to query journal: %s\n", strerror(-r));
- return 1;
- }
- SD_JOURNAL_FOREACH_UNIQUE(j, d, l)
- printf("%.*s\n", (int) l, (const char*) d);
- sd_journal_close(j);
- return 0;
-}</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_get_data</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_journal_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>