sd_info(3) — Linux manual page

SD-DAEMON(3)                      sd-daemon                     SD-DAEMON(3)

NAME top

       sd-daemon, SD_EMERG, SD_ALERT, SD_CRIT, SD_ERR, SD_WARNING,
       SD_NOTICE, SD_INFO, SD_DEBUG - APIs for new-style daemons

SYNOPSIS top

       #include <systemd/sd-daemon.h>

       pkg-config --cflags --libs libsystemd

DESCRIPTION top

       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 (or stdout-based logging) as implemented by
       systemd. If a systemd service definition file is configured with
       StandardError=journal or StandardError=kmsg (and similar with
       StandardOutput=), 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");

NOTES top

       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO top

       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)

COLOPHON top

       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 2020-08-13.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-08-11.)  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 246                                                     SD-DAEMON(3)