1SD-DAEMON(3)                       sd-daemon                      SD-DAEMON(3)
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NAME

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

10       #include <systemd/sd-daemon.h>
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12       pkg-config --cflags --libs libsystemd
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DESCRIPTION

15       sd-daemon.h is part of libsystemd(3) and provides APIs for new-style
16       daemons, as implemented by the systemd(1) service manager.
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18       See sd_listen_fds(3), sd_notify(3), sd_booted(3), sd_is_fifo(3),
19       sd_watchdog_enabled(3) for more information about the functions
20       implemented. In addition to these functions, a couple of logging
21       prefixes are defined as macros:
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23           #define SD_EMERG   "<0>"  /* system is unusable */
24           #define SD_ALERT   "<1>"  /* action must be taken immediately */
25           #define SD_CRIT    "<2>"  /* critical conditions */
26           #define SD_ERR     "<3>"  /* error conditions */
27           #define SD_WARNING "<4>"  /* warning conditions */
28           #define SD_NOTICE  "<5>"  /* normal but significant condition */
29           #define SD_INFO    "<6>"  /* informational */
30           #define SD_DEBUG   "<7>"  /* debug-level messages */
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32       These prefixes are intended to be used in conjunction with stderr-based
33       logging (or stdout-based logging) as implemented by systemd. If a
34       systemd service definition file is configured with
35       StandardError=journal or StandardError=kmsg (and similar with
36       StandardOutput=), these prefixes can be used to encode a log level in
37       lines printed. This is similar to the kernel printk()-style logging.
38       See klogctl(2) for more information.
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40       The log levels are identical to syslog(3)'s log level system. To use
41       these prefixes simply prefix every line with one of these strings. A
42       line that is not prefixed will be logged at the default log level
43       SD_INFO.
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45       Example 1. Hello World
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47       A daemon may log with the log level NOTICE by issuing this call:
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49           fprintf(stderr, SD_NOTICE "Hello World!\n");
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NOTES

52       Functions described here are available as a shared library, which can
53       be compiled against and linked to with the libsystemd pkg-config(1)
54       file.
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56       The code described here uses getenv(3), which is declared to be not
57       multi-thread-safe. This means that the code calling the functions
58       described here must not call setenv(3) from a parallel thread. It is
59       recommended to only do calls to setenv() from an early phase of the
60       program when no other threads have been started.
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SEE ALSO

63       systemd(1), sd_listen_fds(3), sd_notify(3), sd_booted(3),
64       sd_is_fifo(3), sd_watchdog_enabled(3), daemon(7), systemd.service(5),
65       systemd.socket(5), fprintf(3), pkg-config(1)
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69systemd 254                                                       SD-DAEMON(3)
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