<?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">

<refentry id="sd-daemon"

xmlns:xi="http://www.w3.org/2001/XInclude">

<refentryinfo>

<title>sd-daemon</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-daemon</refentrytitle>

<manvolnum>3</manvolnum>

</refmeta>

<refnamediv>

<refname>sd-daemon</refname>

<refname>SD_EMERG</refname>

<refname>SD_ALERT</refname>

<refname>SD_CRIT</refname>

<refname>SD_ERR</refname>

<refname>SD_WARNING</refname>

<refname>SD_NOTICE</refname>

<refname>SD_INFO</refname>

<refname>SD_DEBUG</refname>

<refpurpose>APIs for

new-style daemons</refpurpose>

</refnamediv>

<refsynopsisdiv>

<funcsynopsis>

<funcsynopsisinfo>#include &lt;systemd/sd-daemon.h&gt;</funcsynopsisinfo>

</funcsynopsis>

<cmdsynopsis>

<command>pkg-config --cflags --libs libsystemd</command>

</cmdsynopsis>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para><filename>sd-daemon.h</filename> provide APIs for new-style

daemons, as implemented by the

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>

init system.</para>

<para>See

<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>

for more information about the functions implemented. In addition

to these functions, a couple of logging prefixes are defined as

macros:</para>

<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 */</programlisting>

<para>These prefixes are intended to be used in conjunction with

stderr-based logging as implemented by systemd. If a systemd

service definition file is configured with

<varname>StandardError=journal</varname>,

<varname>StandardError=syslog</varname> or

<varname>StandardError=kmsg</varname>, these prefixes can be used

to encode a log level in lines printed. This is similar to the

kernel <function>printk()</function>-style logging. See

<citerefentry><refentrytitle>klogctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>

for more information.</para>

<para>The log levels are identical to

<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>'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 SD_INFO.</para>

<example>

<title>Hello World</title>

<para>A daemon may log with the log level NOTICE by issuing this

call:</para>

<programlisting>fprintf(stderr, SD_NOTICE "Hello World!\n");</programlisting>

</example>

</refsect1>

<xi:include href="libsystemd-pkgconfig.xml" />

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry project='man-pages'><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>