syslog(3C)						   Standard C Library Functions 						syslog(3C)

NAME

       syslog, openlog, closelog, setlogmask - control system log

SYNOPSIS

       #include <syslog.h>

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

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

       void closelog(void);

       int setlogmask(int maskpri);

DESCRIPTION

       The  syslog() function sends a message to syslogd(1M), which, depending on the configuration of /etc/syslog.conf, logs it in an appropriate
       system log, writes it to the system console, forwards it to a list of users, or forwards it to syslogd on another host  over  the  network.
       The  logged  message  includes  a message header and a message body.  The message header consists of a facility indicator, a severity level
       indicator, a timestamp, a tag string, and optionally the process ID.

       The message body is generated from the message and following arguments in the same manner as  if  these	were  arguments  to  printf(3UCB),
       except  that  occurrences of %m in the format string pointed to by the message argument are replaced by the error message string associated
       with the current value of errno.  A trailing NEWLINE character is added if needed.

       Symbolic constants for use as values of the logopt, facility, priority, and maskpri arguments are defined in the <syslog.h> header.

       Values of the priority argument are formed by ORing together a severity level value and an optional facility value.  If no  facility  value
       is specified, the current default facility value is used.

       Possible values of severity level include, in decreasing order:

       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, such as hard device errors.

       LOG_ERR	      Errors.

       LOG_WARNING    Warning messages.

       LOG_NOTICE     Conditions that are not error conditions, but that may require special handling.

       LOG_INFO       Informational messages.

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

       The facility indicates the application or system component generating the message.  Possible facility values include:

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

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

       LOG_MAIL      The mail system.

       LOG_DAEMON    System daemons, such as in.ftpd(1M).

       LOG_AUTH      The authentication / security / authorization system: login(1), su(1M), getty(1M).

       LOG_LPR	     The line printer spooling system: lpr(1B), lpc(1B).

       LOG_NEWS      Designated for the USENET network news system.

       LOG_UUCP      Designated for the UUCP system; it does not currently use syslog().

       LOG_CRON      The cron/at facility; crontab(1), at(1), cron(1M).

       LOG_AUDIT     The audit facility, for example, auditd(1M).

       LOG_LOCAL0    Designated for local use.

       LOG_LOCAL1    Designated for local use.

       LOG_LOCAL2    Designated for local use.

       LOG_LOCAL3    Designated for local use.

       LOG_LOCAL4    Designated for local use.

       LOG_LOCAL5    Designated for local use.

       LOG_LOCAL6    Designated for local use.

       LOG_LOCAL7    Designated for local use.

       The  openlog()  function sets process attributes that affect subsequent calls to syslog(). The ident argument is a string that is prepended
       to every message. The openlog() function uses the passed-in ident argument directly, rather than making a private copy of  it.  The  logopt
       argument indicates logging options.  Values for logopt are constructed by a bitwise-inclusive OR of zero or more of the following:

       LOG_PID	     Log the process ID with each message.  This is useful for identifying specific daemon processes (for daemons that fork).

       LOG_CONS      Write  messages  to  the system console if they cannot be sent to syslogd(1M). This option is safe to use in daemon processes
		     that have no controlling terminal, since syslog() forks before opening the console.

       LOG_NDELAY    Open the connection to syslogd(1M) immediately.  Normally the open is delayed until the first message is logged. This is use-
		     ful for programs that need to manage the order in which file descriptors are allocated.

       LOG_ODELAY    Delay open until syslog() is called.

       LOG_NOWAIT    Do  not  wait for child processes that have been forked to log messages onto the console.	This option should be used by pro-
		     cesses that enable notification of child termination using SIGCHLD, since syslog() may otherwise block waiting  for  a  child
		     whose exit status has already been collected.

       The facility argument encodes a default facility to be assigned to all messages that do not have an explicit facility already encoded.  The
       initial default facility is LOG_USER.

       The openlog() and syslog() functions may allocate a file descriptor.  It is not necessary to call openlog() prior to calling syslog().

       The closelog() function closes any open file descriptors allocated by previous calls to openlog() or syslog().

       The setlogmask() function sets the log priority mask for the current process to maskpri and returns the	previous  mask.   If  the  maskpri
       argument  is  0,  the  current  log  mask is not modified.  Calls by the current process 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  includ-
       ing toppri is given by the macro LOG_UPTO(toppri). The default log mask allows all priorities to be logged.

RETURN VALUES

       The setlogmask() function returns the previous log priority mask. The closelog(), openlog() and syslog() functions return no value.

ERRORS

       No errors are defined.

EXAMPLES

       Example 1 Example of LOG_ALERT message.

       This call logs a message at priority LOG_ALERT:

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

       The  FTP  daemon  ftpd  would  make this call to openlog() to indicate that all messages it logs should have an identifying string of ftpd,
       should be treated by syslogd(1M) as other messages from system daemons are, should include the process ID of the process logging  the  mes-
       sage:

	 openlog("ftpd", LOG_PID, LOG_DAEMON);

       Then  it  would	make  the  following call to setlogmask() to indicate that messages at priorities from LOG_EMERG through LOG_ERR should be
       logged, but that no messages at any other priority should be logged:

	 setlogmask(LOG_UPTO(LOG_ERR));

       Then, to log a message at priority LOG_INFO, it would make the following call to syslog:

	 syslog(LOG_INFO, "Connection from host %d", CallingHost);

       A locally-written utility could use the following call to syslog() to log a message at priority LOG_INFO to be treated  by  syslogd(1M)	as
       other messages to the facility  LOG_LOCAL2 are:

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

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       at(1),  crontab(1), logger(1), login(1), lpc(1B), lpr(1B), auditd(1M), cron(1M), getty(1M), in.ftpd(1M), su(1M), syslogd(1M), printf(3UCB),
       syslog.conf(4), attributes(5), standards(5)

SunOS 5.11							    16 Mar 2009 							syslog(3C)