mirror of
https://git.proxmox.com/git/systemd
synced 2025-07-24 20:50:26 +00:00
109 lines
9.7 KiB
HTML
109 lines
9.7 KiB
HTML
<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_journal_add_match</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
|
||
a.headerlink {
|
||
color: #c60f0f;
|
||
font-size: 0.8em;
|
||
padding: 0 4px 0 4px;
|
||
text-decoration: none;
|
||
visibility: hidden;
|
||
}
|
||
|
||
a.headerlink:hover {
|
||
background-color: #c60f0f;
|
||
color: white;
|
||
}
|
||
|
||
h1:hover > a.headerlink, h2:hover > a.headerlink, h3:hover > a.headerlink, dt:hover > a.headerlink {
|
||
visibility: visible;
|
||
}
|
||
</style><a href="index.html">Index </a>·
|
||
<a href="systemd.directives.html">Directives </a>·
|
||
<a href="../python-systemd/index.html">Python </a>·
|
||
<a href="../libudev/index.html">libudev </a>·
|
||
<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="sd_journal_add_match"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_journal_add_match, sd_journal_add_disjunction, sd_journal_add_conjunction, sd_journal_flush_matches — Add or remove entry matches</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include <systemd/sd-journal.h></pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_journal_add_match</b>(</code></td><td>sd_journal *<var class="pdparam">j</var>, </td></tr><tr><td> </td><td>const void *<var class="pdparam">data</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_journal_add_disjunction</b>(</code></td><td>sd_journal *<var class="pdparam">j</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_journal_add_conjunction</b>(</code></td><td>sd_journal *<var class="pdparam">j</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <b class="fsfunc">sd_journal_flush_matches</b>(</code></td><td>sd_journal *<var class="pdparam">j</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm140088832477616"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_journal_add_match()</code> adds a match by
|
||
which to filter the entries of the journal file. Matches applied
|
||
with this call will filter what can be iterated through and read
|
||
from the journal file via calls like
|
||
<a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a>
|
||
and
|
||
<a href="sd_journal_get_data.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_get_data</span>(3)</span></a>.
|
||
Matches are of the form "<code class="literal">FIELD=value</code>", where the
|
||
field part is a short uppercase string consisting only of 0-9, A-Z
|
||
and the underscore. It may not begin with two underscores or be
|
||
the empty string. The value part may be any value, including
|
||
binary. If a match is applied, only entries with this field set
|
||
will be iterated. Multiple matches may be active at the same time:
|
||
If they apply to different fields, only entries with both fields
|
||
set like this will be iterated. If they apply to the same fields,
|
||
only entries where the field takes one of the specified values
|
||
will be iterated. Well known fields are documented in
|
||
<a href="systemd.journal-fields.html"><span class="citerefentry"><span class="refentrytitle">systemd.journal-fields</span>(7)</span></a>.
|
||
Whenever a new match is added the current entry position is reset,
|
||
and
|
||
<a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a>
|
||
(or a similar call) needs to be called before entries can be read
|
||
again.</p><p><code class="function">sd_journal_add_disjunction()</code> may be
|
||
used to insert a disjunction (i.e. logical OR) in the match list.
|
||
If this call is invoked, all previously added matches since the
|
||
last invocation of
|
||
<code class="function">sd_journal_add_disjunction()</code> or
|
||
<code class="function">sd_journal_add_conjunction()</code> are combined in
|
||
an OR with all matches added afterwards, until
|
||
<code class="function">sd_journal_add_disjunction()</code> or
|
||
<code class="function">sd_journal_add_conjunction()</code> is invoked again
|
||
to begin the next OR or AND term. </p><p><code class="function">sd_journal_add_conjunction()</code> may be
|
||
used to insert a conjunction (i.e. logical AND) in the match list.
|
||
If this call is invoked, all previously added matches since the
|
||
last invocation of
|
||
<code class="function">sd_journal_add_conjunction()</code> are combined in
|
||
an AND with all matches added afterwards, until
|
||
<code class="function">sd_journal_add_conjunction()</code> is invoked again
|
||
to begin the next AND term. The combination of
|
||
<code class="function">sd_journal_add_match()</code>,
|
||
<code class="function">sd_journal_add_disjunction()</code> and
|
||
<code class="function">sd_journal_add_conjunction()</code> may be used to
|
||
build complex search terms, even though full logical expressions
|
||
are not available. Note that
|
||
<code class="function">sd_journal_add_conjunction()</code> operates one
|
||
level 'higher' than
|
||
<code class="function">sd_journal_add_disjunction()</code>. It is hence
|
||
possible to build an expression of AND terms, consisting of OR
|
||
terms, consisting of AND terms, consisting of OR terms of matches
|
||
(the latter OR expression is implicitly created for matches with
|
||
the same field name, see above).</p><p><code class="function">sd_journal_flush_matches()</code> may be used
|
||
to flush all matches, disjunction and conjunction terms again.
|
||
After this call all filtering is removed and all entries in the
|
||
journal will be iterated again.</p><p>Note that filtering via matches only applies to the way the
|
||
journal is read, it has no effect on storage on disk.</p></div><div class="refsect1"><a name="idm140088836361456"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p><code class="function">sd_journal_add_match()</code>,
|
||
<code class="function">sd_journal_add_disjunction()</code> and
|
||
<code class="function">sd_journal_add_conjunction()</code>
|
||
return 0 on success or a negative errno-style error
|
||
code. <code class="function">sd_journal_flush_matches()</code>
|
||
returns nothing.</p></div><div class="refsect1"><a name="idm140088836350224"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_journal_add_match()</code>,
|
||
<code class="function">sd_journal_add_disjunction()</code>,
|
||
<code class="function">sd_journal_add_conjunction()</code> and
|
||
<code class="function">sd_journal_flush_matches()</code>
|
||
interfaces are available as a shared library, which can
|
||
be compiled and linked to with the
|
||
<code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
|
||
file.</p></div><div class="refsect1"><a name="idm140088836344336"></a><h2 id="Examples">Examples<a class="headerlink" title="Permalink to this headline" href="#Examples">¶</a></h2><p>The following example adds matches to a journal context
|
||
object to iterate only through messages generated by the Avahi
|
||
service at the four error log levels, plus all messages of the
|
||
message ID 03bb1dab98ab4ecfbf6fff2738bdd964 coming from any
|
||
service (this example lacks the necessary error checking):</p><pre class="programlisting">...
|
||
int add_matches(sd_journal *j) {
|
||
sd_journal_add_match(j, "_SYSTEMD_UNIT=avahi-daemon.service", 0);
|
||
sd_journal_add_match(j, "PRIORITY=0", 0);
|
||
sd_journal_add_match(j, "PRIORITY=1", 0);
|
||
sd_journal_add_match(j, "PRIORITY=2", 0);
|
||
sd_journal_add_match(j, "PRIORITY=3", 0);
|
||
sd_journal_add_disjunction(j);
|
||
sd_journal_add_match(j, "MESSAGE_ID=03bb1dab98ab4ecfbf6fff2738bdd964", 0);
|
||
}</pre></div><div class="refsect1"><a name="idm140088836341360"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
|
||
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
|
||
<a href="sd-journal.html"><span class="citerefentry"><span class="refentrytitle">sd-journal</span>(3)</span></a>,
|
||
<a href="sd_journal_open.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_open</span>(3)</span></a>,
|
||
<a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a>,
|
||
<a href="sd_journal_get_data.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_get_data</span>(3)</span></a>,
|
||
<a href="systemd.journal-fields.html"><span class="citerefentry"><span class="refentrytitle">systemd.journal-fields</span>(7)</span></a>
|
||
</p></div></div></body></html>
|