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BSD 2.11 - man page for syslog (bsd section 3)

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SYSLOG(3)										SYSLOG(3)

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

SYNOPSIS
       #include <syslog.h>
       #include <varargs.h>

       void syslog(priority, message, ...);
       int priority;
       char *message;

       void vsyslog(priority, message, args);
       int priority;
       char *message;
       va_list args;

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

       void closelog();

       int setlogmask(maskpri);
       int maskpri;

DESCRIPTION
       The  syslog()  function	writes message to the system message logger.  The message is then
       written to the system console, log files, logged-in users, or forwarded to other  machines
       as appropriate. (See syslogd(8)).

       The  message  is identical to a printf(3) format string, except that %m is replaced by the
       current error message as denoted by the	global	variable  errno.   See	strerror(3)).	A
       trailing newline is added if none is present.

       The  vsyslog() function is an alternate form in which the arguments have already been cap-
       tured using the variable-length argument facilities of varargs(3).

       The message is tagged with priority.  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 the following ordered (high to low) 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 sys-
		       tem 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 possibly be handled
		       specially.

       LOG_INFO        Informational messages.

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

       The  openlog()  function  provides for more specialized processing of the messages sent by
       syslog() and vsyslog().	The parameter ident is a string that will be prepended	to  every
       message.   The  logopt argument is a bit field specifying logging options, which is formed
       by OR'ing one or more of the following values:

       LOG_CONS       If syslog cannot pass the message to syslogd it will attempt to  write  the
		      message to the console (/dev/console).

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

       LOG_PERROR     Write the message to standard error output as well to the system log.

       LOG_PID	      Log the process id with each message: useful for identifying instantiations
		      of daemons.

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

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

       LOG_AUTHPRIV   The same as LOG_AUTH , but logged to a file readable only by selected indi-
		      viduals.

       LOG_CRON       The clock daemon.

       LOG_DAEMON     System daemons, such as routed(8), that are not provided for explicitly  by
		      other facilities.

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

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

       LOG_MAIL       The mail system.

       LOG_NEWS       The network news system.

       LOG_SYSLOG     Messages generated internally by syslogd(8).

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

       LOG_UUCP       The uucp system.

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

       The closelog function can be used to close the log file.

       The  setlogmask	function  sets	the log priority mask to maskpri and returns the previous
       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 prior-
       ities up to and including toppri is given by  the  macro  LOG_UPTO(toppri).   The  default
       allows all priorities to be logged.

RETURN VALUES
       The routines closelog(), openlog(), syslog() and vsyslog() return no value.

       The routine setlogmask() always returns the previous log mask level.

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

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

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

SEE ALSO
       logger(1), syslogd(8)

BUGS
       Under 2.11BSD the logfile /usr/adm/messages is used if a non networking	kernel	has  been
       booted.	That file must be publically writeable in this case.

HISTORY
       These functions appeared in 4.2BSD.

4.2 Berkeley Distribution		  April 1, 1995 				SYSLOG(3)
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