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SD-DAEMON(3) sd-daemon SD-DAEMON(3)
sd-daemon, SD_EMERG, SD_ALERT, SD_CRIT, SD_ERR, SD_WARNING,
SD_NOTICE, SD_INFO, SD_DEBUG - APIs for new-style daemons
#include <systemd/sd-daemon.h>
pkg-config --cflags --libs libsystemd
sd-daemon.h provides APIs for new-style daemons, as implemented by
the systemd(1) service manager.
See sd_listen_fds(3), sd_notify(3), sd_booted(3), sd_is_fifo(3),
sd_watchdog_enabled(3) for more information about the functions
implemented. In addition to these functions, a couple of logging
prefixes are defined as macros:
#define SD_EMERG "<0>" /* system is unusable */
#define SD_ALERT "<1>" /* action must be taken immediately */
#define SD_CRIT "<2>" /* critical conditions */
#define SD_ERR "<3>" /* error conditions */
#define SD_WARNING "<4>" /* warning conditions */
#define SD_NOTICE "<5>" /* normal but significant condition */
#define SD_INFO "<6>" /* informational */
#define SD_DEBUG "<7>" /* debug-level messages */
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 StandardError=journal,
StandardError=syslog or StandardError=kmsg, these prefixes can be
used to encode a log level in lines printed. This is similar to the
kernel printk()-style logging. See klogctl(2) for more information.
The log levels are identical to syslog(3)'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.
Example 1. Hello World
A daemon may log with the log level NOTICE by issuing this call:
fprintf(stderr, SD_NOTICE "Hello World!\n");
These APIs are implemented as a shared library, which can be compiled
and linked to with the libsystemd pkg-config(1) file.
systemd(1), sd_listen_fds(3), sd_notify(3), sd_booted(3),
sd_is_fifo(3), sd_watchdog_enabled(3), daemon(7), systemd.service(5),
systemd.socket(5), fprintf(3), pkg-config(1)
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2018-02-02. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2018-02-02.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
systemd 234 SD-DAEMON(3)
Pages that refer to this page: systemd(1), sd_booted(3), sd_is_fifo(3), sd_journal_stream_fd(3), sd_listen_fds(3), sd-login(3), sd_notify(3), sd_watchdog_enabled(3), systemd.exec(5), daemon(7), systemd.directives(7), systemd.index(7)
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HTML rendering created 2018-02-02 by Michael Kerrisk, author of The Linux Programming Interface, maintainer of the Linux man-pages project. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.
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