\section{\module{syslog} ---         \UNIX{} syslog library routines} \declaremodule{builtin}{syslog}  \platform{Unix}\modulesynopsis{An interface to the \UNIX\ syslog library routines.}  This module provides an interface to the \UNIX{} \code{syslog} libraryroutines.  Refer to the \UNIX{} manual pages for a detailed descriptionof the \code{syslog} facility. The module defines the following functions:  \begin{funcdesc}{syslog}{\optional{priority,} message}Send the string \var{message} to the system logger.  A trailingnewline is added if necessary.  Each message is tagged with a prioritycomposed of a \var{facility} and a \var{level}.  The optional\var{priority} argument, which defaults to \constant{LOG_INFO},determines the message priority.  If the facility is not encoded in\var{priority} using logical-or (\code{LOG_INFO | LOG_USER}), thevalue given in the \function{openlog()} call is used.\end{funcdesc} \begin{funcdesc}{openlog}{ident\optional{, logopt\optional{, facility}}}Logging options other than the defaults can be set by explicitlyopening the log file with \function{openlog()} prior to calling\function{syslog()}.  The defaults are (usually) \var{ident} =\code{'syslog'}, \var{logopt} = \code{0}, \var{facility} =\constant{LOG_USER}.  The \var{ident} argument is a string which isprepended to every message.  The optional \var{logopt} argument is abit field - see below for possible values to combine.  The optional\var{facility} argument sets the default facility for messages whichdo not have a facility explicitly encoded.\end{funcdesc} \begin{funcdesc}{closelog}{}Close the log file.\end{funcdesc} \begin{funcdesc}{setlogmask}{maskpri}Set the priority mask to \var{maskpri} and return theprevious mask value.  Calls to \function{syslog()} with a prioritylevel not set in \var{maskpri} are ignored.  The default is to log allpriorities.  The function \code{LOG_MASK(\var{pri})} calculates themask for the individual priority \var{pri}.  The function\code{LOG_UPTO(\var{pri})} calculates the mask for all priorities upto and including \var{pri}.\end{funcdesc}  The module defines the following constants: \begin{description} \item[Priority levels (high to low):] \constant{LOG_EMERG}, \constant{LOG_ALERT}, \constant{LOG_CRIT},\constant{LOG_ERR}, \constant{LOG_WARNING}, \constant{LOG_NOTICE},\constant{LOG_INFO}, \constant{LOG_DEBUG}. \item[Facilities:] \constant{LOG_KERN}, \constant{LOG_USER}, \constant{LOG_MAIL},\constant{LOG_DAEMON}, \constant{LOG_AUTH}, \constant{LOG_LPR},\constant{LOG_NEWS}, \constant{LOG_UUCP}, \constant{LOG_CRON} and\constant{LOG_LOCAL0} to \constant{LOG_LOCAL7}. \item[Log options:] \constant{LOG_PID}, \constant{LOG_CONS}, \constant{LOG_NDELAY},\constant{LOG_NOWAIT} and \constant{LOG_PERROR} if defined in\code{<syslog.h>}. \end{description}