sd-daemon

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



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

SYNOPSIS
       #include <systemd/sd-daemon.h>

       pkg-config --cflags --libs libsystemd

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

SEE ALSO
       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)



systemd 246                                                         SD-DAEMON(3)