4.3BSD-UWisc/man/cat3/syslog.3

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



NAME
     syslog, openlog, closelog, setlogmask - control system log

SYNOPSIS
     #include <syslog.h>

     openlog(ident, logopt, facility)
     char *ident;

     syslog(priority, message, parameters ... )
     char *message;

     closelog()

     setlogmask(maskpri)

DESCRIPTION
     _S_y_s_l_o_g arranges to write _m_e_s_s_a_g_e onto the system log main-
     tained by _s_y_s_l_o_g_d(8).  The message is tagged with _p_r_i_o_r_i_t_y.
     The message looks like a _p_r_i_n_t_f(3) string except that %m is
     replaced by the current error message (collected from
     _e_r_r_n_o).  A trailing newline is added if needed.  This mes-
     sage will be read by _s_y_s_l_o_g_d(8) and written to the system
     console, log files, or forwarded to _s_y_s_l_o_g_d on another host
     as appropriate.

     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 an ordered list:

     LOG_EMERG     A panic condition.  This is normally broadcast
                   to all users.

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

     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.

     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 on /_d_e_v/_c_o_n_s_o_l_e if the LOG_CONS



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



     option is set (see below).

     If special processing is needed, _o_p_e_n_l_o_g can be called to
     initialize the log file.  The parameter _i_d_e_n_t is a string
     that is prepended to every message.  _L_o_g_o_p_t is a bit field
     indicating logging options.  Current values for _l_o_g_o_p_t are:

     LOG_PID       log the process id with each message: useful
                   for identifying instantiations of daemons.

     LOG_CONS      Force writing messages to the console if
                   unable to send it to _s_y_s_l_o_g_d. This option is
                   safe to use in daemon processes that have no
                   controlling terminal since _s_y_s_l_o_g will fork
                   before opening the 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_NOWAIT    Don't wait for children forked to log messages
                   on the console.  This option should be used by
                   processes that enable notification of child
                   termination via SIGCHLD, as _s_y_s_l_o_g may other-
                   wise block waiting for a child whose exit
                   status has already been collected.

     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_KERN      Messages generated by the kernel.  These can-
                   not 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 _f_t_p_d(8), _r_o_u_t_e_d(8),
                   etc.

     LOG_AUTH      The authorization system: _l_o_g_i_n(1), _s_u(1),
                   _g_e_t_t_y(8), etc.

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

     LOG_LOCAL0    Reserved for local use.  Similarly for



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



                   LOG_LOCAL1 through LOG_LOCAL7.

     _C_l_o_s_e_l_o_g can be used to close the log file.

     _S_e_t_l_o_g_m_a_s_k 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 prior-
     ity _p_r_i is calculated by the macro LOG_MASK(_p_r_i); the mask
     for all priorities up to and including _t_o_p_p_r_i is given by
     the macro LOG_UPTO(_t_o_p_p_r_i).  The default allows all priori-
     ties to be logged.

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
     logger(1), syslogd(8)
































Printed 12/27/86          May 15, 1986                          3