SYSLOG(3)	    UNIX Programmer's 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 _s_y_s_l_o_g() function writes _m_e_s_s_a_g_e 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 _s_y_s_l_o_g_d(8)).

     The message is identical to a _p_r_i_n_t_f(3) format string,
     except that %m is replaced by the current error message as
     denoted by the global variable _e_r_r_n_o.  See _s_t_r_e_r_r_o_r(3)).  A
     trailing newline is added if none is present.

     The _v_s_y_s_l_o_g() function is an alternate form in which the
     arguments have already been captured using the variable-
     length argument facilities of _v_a_r_a_r_g_s(3).

     The message is tagged with _p_r_i_o_r_i_t_y.  Priorities are encoded
     as a _f_a_c_i_l_i_t_y and a _l_e_v_e_l.  The facility describes the part
     of the system generating the message.  The level is selected
     from the following _o_r_d_e_r_e_d (high to low) list:

     LOG_EMERG	     A panic condition.  This is normally broad-
		     cast to all users.

     LOG_ALERT	     A condition that should be corrected immedi-
		     ately, such as a corrupted system database.



Printed 11/26/99	  April 1, 1995                         1






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



     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 _o_p_e_n_l_o_g() function provides for more specialized pro-
     cessing of the messages sent by _s_y_s_l_o_g() and _v_s_y_s_l_o_g().  The
     parameter _i_d_e_n_t is a string that will be prepended to every
     message.  The _l_o_g_o_p_t argument is a bit field specifying log-
     ging options, which is formed by OR'ing one or more of the
     following values:

     LOG_CONS	    If _s_y_s_l_o_g cannot pass the message to _s_y_s_l_o_g_d
		    it will attempt to write the message to the
		    console (/dev/console).

     LOG_NDELAY     Open the connection to _s_y_s_l_o_g_d 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 _f_a_c_i_l_i_t_y parameter encodes a default facility to be
     assigned to all messages that do not have an explicit facil-
     ity encoded:

     LOG_AUTH	    The authorization system: _l_o_g_i_n(1), _s_u(1),
		    _g_e_t_t_y(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 _r_o_u_t_e_d(8), that are
		    not provided for explicitly by other



Printed 11/26/99	  April 1, 1995                         2






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



		    facilities.

     LOG_KERN	    Messages generated by the kernel.  These can-
		    not be generated by any user processes.

     LOG_LPR	    The line printer spooling system: _l_p_r(1),
		    _l_p_c(8), _l_p_d(8), etc.

     LOG_MAIL	    The mail system.

     LOG_NEWS	    The network news system.

     LOG_SYSLOG     Messages generated internally by _s_y_s_l_o_g_d(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 _c_l_o_s_e_l_o_g function can be used to close the log file.

     The _s_e_t_l_o_g_m_a_s_k function sets the log priority mask to
     _m_a_s_k_p_r_i and returns the previous mask.  Calls to _s_y_s_l_o_g with
     a priority not set in _m_a_s_k_p_r_i are rejected.  The mask for an
     individual priority _p_r_i is calculated by the macro
     _L_O_G__M_A_S_K(pri).  The mask for all priorities up to and
     including _t_o_p_p_r_i is given by the macro _L_O_G__U_P_T_O(toppri).
     The default allows all priorities to be logged.

RETURN VALUES
     The routines _c_l_o_s_e_l_o_g(), _o_p_e_n_l_o_g(), _s_y_s_l_o_g() and _v_s_y_s_l_o_g()
     return no value.

     The routine _s_e_t_l_o_g_m_a_s_k() 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
     _l_o_g_g_e_r(_1), _s_y_s_l_o_g_d(_8)




Printed 11/26/99	  April 1, 1995                         3






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



BUGS
     Under 2.11BSD the logfile /usr/adm/messages is used if a non
     networking kernel has been booted.  That file must be publi-
     cally writeable in this case.

HISTORY
     These functions appeared in 4.2BSD.
















































Printed 11/26/99	  April 1, 1995                         4