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diff --git a/man/sd_journal_set_data_threshold.html b/man/sd_journal_set_data_threshold.html new file mode 100644 index 0000000000..924d74ecf0 --- /dev/null +++ b/man/sd_journal_set_data_threshold.html @@ -0,0 +1,126 @@ +<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_journal_get_data</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 204</span><hr><div class="refentry"><a name="sd_journal_get_data"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_journal_get_data, sd_journal_enumerate_data, sd_journal_restart_data, SD_JOURNAL_FOREACH_DATA, sd_journal_set_data_threshold, sd_journal_get_data_threshold — Read data fields from the current journal entry</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_get_data</b>(</code></td><td>sd_journal* <var class="pdparam">j</var>, </td></tr><tr><td> </td><td>const char* <var class="pdparam">field</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">length</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_enumerate_data</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">length</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_restart_data</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"><b class="fsfunc">SD_JOURNAL_FOREACH_DATA</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">length</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_set_data_threshold</b>(</code></td><td>sd_journal* <var class="pdparam">j</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">sz</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_get_data_threshold</b>(</code></td><td>sd_journal* <var class="pdparam">j</var>, </td></tr><tr><td> </td><td>size_t* <var class="pdparam">sz</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm259782712960"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_journal_get_data()</code> gets + the data object associated with a specific field from + the current journal entry. It takes four arguments: + the journal context object, a string with the field + name to request, plus a pair of pointers to + pointer/size variables where the data object and its + size shall be stored in. The field name should be an + entry field name. Well-known field names are listed in + <a href="systemd.journal-fields.html"><span class="citerefentry"><span class="refentrytitle">systemd.journal-fields</span>(7)</span></a>. The + returned data is in a read-only memory map and is only + valid until the next invocation of + <code class="function">sd_journal_get_data()</code> or + <code class="function">sd_journal_enumerate_data()</code>, or + the read pointer is altered. Note that the data + returned will be prefixed with the field name and + '='. Also note that by default data fields larger than + 64K might get truncated to 64K. This threshold may be + changed and turned off with + <code class="function">sd_journal_set_data_threshold()</code> (see + below).</p><p><code class="function">sd_journal_enumerate_data()</code> + may be used to iterate through all fields of the + current entry. On each invocation the data for the + next field is returned. The order of these fields is + not defined. The data returned is in the same format + as with <code class="function">sd_journal_get_data()</code> and + also follows the same life-time semantics.</p><p><code class="function">sd_journal_restart_data()</code> + resets the data enumeration index to the beginning of + the entry. The next invocation of + <code class="function">sd_journal_enumerate_data()</code> will return the first + field of the entry again.</p><p>Note that the + <code class="function">SD_JOURNAL_FOREACH_DATA()</code> macro + may be used as a handy wrapper around + <code class="function">sd_journal_restart_data()</code> and + <code class="function">sd_journal_enumerate_data()</code>.</p><p>Note that these functions will not work before + <a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a> + (or related call) has been called at least + once, in order to position the read pointer at a valid entry.</p><p><code class="function">sd_journal_set_data_threshold()</code> + may be used to change the data field size threshold + for data returned by + <code class="function">sd_journal_get_data()</code>, + <code class="function">sd_journal_enumerate_data()</code> and + <code class="function">sd_journal_enumerate_unique()</code>. This + threshold is a hint only: it indicates that the client + program is interested only in the initial parts of the + data fields, up to the threshold in size -- but the + library might still return larger data objects. That + means applications should not rely exclusively on this + setting to limit the size of the data fields returned, + but need to apply a explicit size limit on the + returned data as well. This threshold defaults to 64K + by default. To retrieve the complete data fields this + threshold should be turned off by setting it to 0, so + that the library always returns the complete data + objects. It is recommended to set this threshold as + low as possible since this relieves the library from + having to decompress large compressed data objects in + full.</p><p><code class="function">sd_journal_get_data_threshold()</code> + returns the currently configured data field size + threshold.</p></div><div class="refsect1"><a name="idm259782687296"></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_get_data()</code> + returns 0 on success or a negative errno-style error + code. If the current entry does not include the + specified field -ENOENT is returned. If + <a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a> + has not been called at least once -EADDRNOTAVAIL is + returned. <code class="function">sd_journal_enumerate_data()</code> + returns a positive integer if the next field has been + read, 0 when no more fields are known, or a negative + errno-style error + code. <code class="function">sd_journal_restart_data()</code> + returns + nothing. <code class="function">sd_journal_set_data_threshold()</code> + and <code class="function">sd_journal_get_threshold()</code> + return 0 on success or a negative errno-style error + code.</p></div><div class="refsect1"><a name="idm259782681248"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_journal_get_data()</code>, + <code class="function">sd_journal_enumerate_data()</code>, + <code class="function">sd_journal_restart_data()</code>, + <code class="function">sd_journal_set_data_threshold()</code> + and + <code class="function">sd_journal_get_data_threshold()</code> + interfaces are available as shared library, which can + be compiled and linked to with the + <code class="literal">libsystemd-journal</code> + <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a> + file.</p></div><div class="refsect1"><a name="idm259777759888"></a><h2 id="Examples">Examples<a class="headerlink" title="Permalink to this headline" href="#Examples">¶</a></h2><p>See + <a href="sd_journal_next.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_next</span>(3)</span></a> + for a complete example how to use + <code class="function">sd_journal_get_data()</code>.</p><p>Use the + <code class="function">SD_JOURNAL_FOREACH_DATA</code> macro to + iterate through all fields of the current journal + entry:</p><pre class="programlisting">... +int print_fields(sd_journal *j) { + const void *data; + size_t l; + SD_JOURNAL_FOREACH_DATA(j, data, length) + printf("%.*s\n", (int) length, data); +} +...</pre></div><div class="refsect1"><a name="idm259777755392"></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="systemd.journal-fields.html"><span class="citerefentry"><span class="refentrytitle">systemd.journal-fields</span>(7)</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_realtime_usec.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_get_realtime_usec</span>(3)</span></a>, + <a href="sd_journal_query_unique.html"><span class="citerefentry"><span class="refentrytitle">sd_journal_query_unique</span>(3)</span></a> + </p></div></div></body></html> |