4.3BSD - /usr/man/cat3/syslog.0

SYSLOG(3)                                                            SYSLOG(3)


NAME
       syslog, openlog, closelog, setlogmask - control system log

SYNOPSIS
       #include <syslog.h>

       openlog(ident, logopt, facility)
       char *ident;

       syslog(priority, message, parameters ... )
       char *message;

       closelog()

       setlogmask(maskpri)

DESCRIPTION
       Syslog arranges to write message onto the system log maintained by sys���
       logd(8).  The message is tagged with priority.  The message looks  like
       a printf(3) string except that %m is replaced by the current error mes‐
       sage (collected from errno).  A trailing newline is  added  if  needed.
       This  message will be read by syslogd(8) and written to the system con‐
       sole, log files, or forwarded to syslogd on another host  as  appropri‐
       ate.

       Priorities  are  encoded  as  a  facility  and  a  level.  The facility
       describes the part of the system generating the message.  The level  is
       selected from an ordered list:

       LOG_EMERG     A  panic  condition.   This  is normally broadcast to all
                     users.

       LOG_ALERT     A condition that should be corrected immediately, such as
                     a corrupted system database.

       LOG_CRIT      Critical conditions, e.g., hard device errors.

       LOG_ERR       Errors.

       LOG_WARNING   Warning messages.

       LOG_NOTICE    Conditions that are not error conditions, but should pos‐
                     sibly be handled specially.

       LOG_INFO      Informational messages.

       LOG_DEBUG     Messages that contain information normally  of  use  only
                     when debugging a program.

       If  syslog cannot pass the message to syslogd, it will attempt to write
       the message on /dev/console if the LOG_CONS option is set (see  below).

       If  special  processing  is needed, openlog can be called to initialize
       the log file.  The parameter ident is a string  that  is  prepended  to
       every message.  Logopt is a bit field indicating logging options.  Cur‐
       rent values for logopt are:

       LOG_PID       log the process id with each message: useful for  identi‐
                     fying instantiations of daemons.

       LOG_CONS      Force  writing  messages to the console if unable to send
                     it to syslogd.  This option is  safe  to  use  in  daemon
                     processes  that have no controlling terminal since syslog
                     will fork before opening the console.

       LOG_NDELAY    Open the connection to syslogd immediately.  Normally the
                     open  is delayed until the first message is logged.  Use‐
                     ful for programs that need to manage the order  in  which
                     file descriptors are allocated.

       LOG_NOWAIT    Don’t  wait  for  children  forked to log messages on the
                     console.  This option should be used  by  processes  that
                     enable  notification of child termination via SIGCHLD, as
                     syslog may otherwise block waiting for a child whose exit
                     status has already been collected.

       The facility parameter encodes a default facility to be assigned to all
       messages that do not have an explicit facility encoded:

       LOG_KERN      Messages generated by the kernel.  These cannot be gener‐
                     ated by any user processes.

       LOG_USER      Messages generated by random user processes.  This is the
                     default facility identifier if none is specified.

       LOG_MAIL      The mail system.

       LOG_DAEMON    System daemons, such as ftpd(8), routed(8), etc.

       LOG_AUTH      The authorization system: login(1), su(1), getty(8), etc.

       LOG_LPR       The line printer spooling system: lpr(1), lpc(8), lpd(8),
                     etc.

       LOG_LOCAL0    Reserved for local use.  Similarly for LOG_LOCAL1 through
                     LOG_LOCAL7.

       Closelog can be used to close the log file.

       Setlogmask sets the log priority mask to maskpri and returns the previ‐
       ous mask.  Calls to syslog with a  priority  not  set  in  maskpri  are
       rejected.  The mask for an individual priority pri is calculated by the
       macro LOG_MASK(pri); the mask for all priorities up  to  and  including
       toppri  is given by the macro LOG_UPTO(toppri).  The default allows all
       priorities to be logged.

EXAMPLES
       syslog(LOG_ALERT, "who: internal error 23");

       openlog("ftpd", LOG_PID, LOG_DAEMON);
       setlogmask(LOG_UPTO(LOG_ERR));
       syslog(LOG_INFO, "Connection from host %d", CallingHost);

       syslog(LOG_INFO|LOG_LOCAL2, "foobar error: %m");

SEE ALSO
       logger(1), syslogd(8)


4.2 Berkeley Distribution        May 15, 1986                        SYSLOG(3)