SYSLOG(3)						     Library Functions Manual							 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 captured 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 gen-
       erating 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 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 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 individuals.

       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 priorities 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)); syslog(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)