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  <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 215</span><hr><div class="refentry"><a name="sd-daemon"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd-daemon, SD_EMERG, SD_ALERT, SD_CRIT, SD_ERR, SD_WARNING, SD_NOTICE, SD_INFO, SD_DEBUG — APIs for
                new-style daemons</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-daemon.h&gt;</pre></div><div class="cmdsynopsis"><p><code class="command">pkg-config --cflags --libs libsystemd</code> </p></div></div><div class="refsect1"><a name="idm214195900512"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p><code class="filename">sd-daemon.h</code> provide APIs
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                for new-style daemons, as implemented by the
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                <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>
                init system.</p><p>See
                <a href="sd_listen_fds.html"><span class="citerefentry"><span class="refentrytitle">sd_listen_fds</span>(3)</span></a>,
                <a href="sd_notify.html"><span class="citerefentry"><span class="refentrytitle">sd_notify</span>(3)</span></a>,
                <a href="sd_booted.html"><span class="citerefentry"><span class="refentrytitle">sd_booted</span>(3)</span></a>,
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                <a href="sd_is_fifo.html"><span class="citerefentry"><span class="refentrytitle">sd_is_fifo</span>(3)</span></a>,
                <a href="sd_watchdog_enabled.html"><span class="citerefentry"><span class="refentrytitle">sd_watchdog_enabled</span>(3)</span></a>
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                for more information about the functions
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                implemented. In addition to these functions, a couple
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                of logging prefixes are defined as macros:</p><pre class="programlisting">#define SD_EMERG   "&lt;0&gt;"  /* system is unusable */
#define SD_ALERT   "&lt;1&gt;"  /* action must be taken immediately */
#define SD_CRIT    "&lt;2&gt;"  /* critical conditions */
#define SD_ERR     "&lt;3&gt;"  /* error conditions */
#define SD_WARNING "&lt;4&gt;"  /* warning conditions */
#define SD_NOTICE  "&lt;5&gt;"  /* normal but significant condition */
#define SD_INFO    "&lt;6&gt;"  /* informational */
#define SD_DEBUG   "&lt;7&gt;"  /* debug-level messages */</pre><p>These prefixes are intended to be used in
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                conjunction with stderr-based logging as implemented
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                by systemd. If a systemd service definition file is
                configured with <code class="varname">StandardError=syslog</code>
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                or <code class="varname">StandardError=kmsg</code>, these
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                prefixes can be used to encode a log level in lines
                printed. This is similar to the kernel
                <code class="function">printk()</code>-style logging. See
                <a href="klogctl.html"><span class="citerefentry"><span class="refentrytitle">klogctl</span>(2)</span></a>
                for more information.</p><p>The log levels are identical to
                <a href="syslog.html"><span class="citerefentry"><span class="refentrytitle">syslog</span>(3)</span></a>'s
                log level system. To use these prefixes simply prefix
                every line with one of these strings. A line that is
                not prefixed will be logged at the default log level
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                SD_INFO.</p><div class="example"><a name="idm214195045552"></a><p class="title"><b>Example 1. Hello World</b></p><div class="example-contents"><p>A daemon may log with the log level
                        NOTICE by issuing this call:</p><pre class="programlisting">fprintf(stderr, SD_NOTICE "Hello World!\n");</pre></div></div><br class="example-break"></div><div class="refsect1"><a name="idm214192388800"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes"></a></h2><p><a name="pkgconfig-text"></a>These APIs are implemented as a shared
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  library, which can be compiled and linked to with the
  <code class="constant">libsystemd</code> <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
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  file.</p></div><div class="refsect1"><a name="idm214193723968"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
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                        <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
                        <a href="sd_listen_fds.html"><span class="citerefentry"><span class="refentrytitle">sd_listen_fds</span>(3)</span></a>,
                        <a href="sd_notify.html"><span class="citerefentry"><span class="refentrytitle">sd_notify</span>(3)</span></a>,
                        <a href="sd_booted.html"><span class="citerefentry"><span class="refentrytitle">sd_booted</span>(3)</span></a>,
                        <a href="sd_is_fifo.html"><span class="citerefentry"><span class="refentrytitle">sd_is_fifo</span>(3)</span></a>,
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                        <a href="sd_watchdog_enabled.html"><span class="citerefentry"><span class="refentrytitle">sd_watchdog_enabled</span>(3)</span></a>,
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                        <a href="daemon.html"><span class="citerefentry"><span class="refentrytitle">daemon</span>(7)</span></a>,
                        <a href="systemd.service.html"><span class="citerefentry"><span class="refentrytitle">systemd.service</span>(5)</span></a>,
                        <a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a>,
                        <a href="fprintf.html"><span class="citerefentry"><span class="refentrytitle">fprintf</span>(3)</span></a>,
                        <a href="sd-readahead.html"><span class="citerefentry"><span class="refentrytitle">sd-readahead</span>(3)</span></a>,
                        <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
                </p></div></div></body></html>