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 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");
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)
Referenced By
daemon(7), 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(1), systemd.directives(7), systemd.exec(5), systemd.index(7).
The man pages SD_ALERT(3), SD_CRIT(3), SD_DEBUG(3), SD_EMERG(3), SD_ERR(3), SD_INFO(3), SD_NOTICE(3) and SD_WARNING(3) are aliases of sd-daemon(3).