


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 dis-
       tributed 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 con-
              nection is opened when the first message is logged)

       LOG_PERROR
              print to stderr as well




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


       LOG_PID
              include PID with each message

   facility
       The facility argument is used to specify what type of pro-
       gram 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




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


       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)





























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