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systemd/man/sd-daemon.xml
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

134 lines
5.3 KiB
XML

<?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">
<!--
SPDX-License-Identifier: LGPL-2.1+
This file is part of systemd.
Copyright 2010 Lennart Poettering
-->
<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> provides APIs for new-style
daemons, as implemented by the
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
service manager.</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>