man/sd-daemon.3

   1 '\" t
   2 .TH "SD\-DAEMON" "3" "" "systemd 214" "sd-daemon"
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  20 .\" * MAIN CONTENT STARTS HERE *
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  22 .SH "NAME"
  23 sd-daemon, SD_EMERG, SD_ALERT, SD_CRIT, SD_ERR, SD_WARNING, SD_NOTICE, SD_INFO, SD_DEBUG \- APIs for new\-style daemons
  24 .SH "SYNOPSIS"
  25 .sp
  26 .ft B
  27 .nf
  28 #include <systemd/sd\-daemon\&.h>
  29 .fi
  30 .ft
  31 .HP \w'\fBpkg\-config\ \-\-cflags\ \-\-libs\ libsystemd\fR\ 'u
  32 \fBpkg\-config \-\-cflags \-\-libs libsystemd\fR
  33 .SH "DESCRIPTION"
  34 .PP
  35 sd\-daemon\&.h
  36 provide APIs for new\-style daemons, as implemented by the
  37 \fBsystemd\fR(1)
  38 init system\&.
  39 .PP
  40 See
  41 \fBsd_listen_fds\fR(3),
  42 \fBsd_notify\fR(3),
  43 \fBsd_booted\fR(3),
  44 \fBsd_is_fifo\fR(3),
  45 \fBsd_watchdog_enabled\fR(3)
  46 for more information about the functions implemented\&. In addition to these functions, a couple of logging prefixes are defined as macros:
  47 .sp
  48 .if n \{\
  49 .RS 4
  50 .\}
  51 .nf
  52 #define SD_EMERG   "<0>"  /* system is unusable */
  53 #define SD_ALERT   "<1>"  /* action must be taken immediately */
  54 #define SD_CRIT    "<2>"  /* critical conditions */
  55 #define SD_ERR     "<3>"  /* error conditions */
  56 #define SD_WARNING "<4>"  /* warning conditions */
  57 #define SD_NOTICE  "<5>"  /* normal but significant condition */
  58 #define SD_INFO    "<6>"  /* informational */
  59 #define SD_DEBUG   "<7>"  /* debug\-level messages */
  60 .fi
  61 .if n \{\
  62 .RE
  63 .\}
  64 .PP
  65 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
  66 \fIStandardError=syslog\fR
  67 or
  68 \fIStandardError=kmsg\fR, these prefixes can be used to encode a log level in lines printed\&. This is similar to the kernel
  69 \fBprintk()\fR\-style logging\&. See
  70 \fBklogctl\fR(2)
  71 for more information\&.
  72 .PP
  73 The log levels are identical to
  74 \fBsyslog\fR(3)\*(Aqs 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\&.
  75 .PP
  76 \fBExample\ \&1.\ \&Hello World\fR
  77 .PP
  78 A daemon may log with the log level NOTICE by issuing this call:
  79 .sp
  80 .if n \{\
  81 .RS 4
  82 .\}
  83 .nf
  84 fprintf(stderr, SD_NOTICE "Hello World!\en");
  85 .fi
  86 .if n \{\
  87 .RE
  88 .\}
  89 .SH "NOTES"
  90 .PP
  91 These APIs are implemented as a shared library, which can be compiled and linked to with the
  92 \fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
  93 file\&.
  94 .SH "SEE ALSO"
  95 .PP
  96 \fBsystemd\fR(1),
  97 \fBsd_listen_fds\fR(3),
  98 \fBsd_notify\fR(3),
  99 \fBsd_booted\fR(3),
 100 \fBsd_is_fifo\fR(3),
 101 \fBsd_watchdog_enabled\fR(3),
 102 \fBdaemon\fR(7),
 103 \fBsystemd.service\fR(5),
 104 \fBsystemd.socket\fR(5),
 105 \fBfprintf\fR(3),
 106 \fBsd-readahead\fR(3),
 107 \fBpkg-config\fR(1)