syslog

SYSLOG(3)                   Linux Programmer's Manual                  SYSLOG(3)



NAME
       closelog, openlog, syslog - send messages to the system logger

SYNOPSIS
       #include <syslog.h>

       void openlog( char *ident, int option, int  facility)

       void syslog( int priority, char *format, ...)

       void closelog( void )


DESCRIPTION
       closelog() closes the descriptor being used to write to the system
       logger.  The use of closelog() is optional.

       openlog() opens a connection to the system logger for a program.  The
       string pointed to by ident is added to each message, and is typically set
       to the program name.  Values for option and facility are given in the
       next section.  The use of openlog() is optional; It will automatically be
       called by syslog() if necessary, in which case ident will default to
       NULL.

       syslog() generates a log message, which will be distributed by
       syslogd(8).  priority is a combination of the facility and the level,
       values for which are given in the next section.  The remaining arguments
       are a format, as in printf(3) and any arguments required by the format,
       except that the two character %m will be replaced by the error message
       string (strerror) corresponding to the present value of errno.


PARAMETERS
       This section lists the parameters used to set the values of option,
       facility, and priority.

   option
       The option argument to openlog() is an OR of any of these:

       LOG_CONS
              write directly to system console if there is an error while
              sending to system logger

       LOG_NDELAY
              open the connection immediately (normally, the connection is
              opened when the first message is logged)

       LOG_PERROR
              print to stderr as well

       LOG_PID
              include PID with each message

   facility
       The facility argument is used to specify what type of program is logging
       the message.  This lets the configuration file specify that messages from
       different facilities will be handled differently.

       LOG_AUTH
              security/authorization messages (DEPRECATED Use LOG_AUTHPRIV
              instead)

       LOG_AUTHPRIV
              security/authorization messages (private)

       LOG_CRON
              clock daemon (cron and at)

       LOG_DAEMON
              other system daemons

       LOG_KERN
              kernel messages

       LOG_LOCAL0 through LOG_LOCAL7
              reserved for local use

       LOG_LPR
              line printer subsystem

       LOG_MAIL
              mail subsystem

       LOG_NEWS
              USENET news subsystem

       LOG_SYSLOG
              messages generated internally by syslogd

       LOG_USER(default)
              generic user-level messages

       LOG_UUCP
              UUCP subsystem


   level
       This determines the importance of the message.  The levels are, in order
       of decreasing importance:

       LOG_EMERG
              system is unusable

       LOG_ALERT
              action must be taken immediately

       LOG_CRIT
              critical conditions

       LOG_ERR
              error conditions

       LOG_WARNING
              warning conditions

       LOG_NOTICE
              normal, but significant, condition

       LOG_INFO
              informational message

       LOG_DEBUG
              debug-level message



HISTORY
       A syslog function call appeared in BSD 4.2.

SEE ALSO
       logger(1), syslog.conf(5), syslogd(8)



Linux                              15 Feb 1994                         SYSLOG(3)