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 (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");
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 2021-08-27. (At that time, the date of the most recent commit that was found in the repository was 2021-08-27.) 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 email@example.com systemd 249 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)