syslog(3) DG/UX 4.30 syslog(3)
NAME
syslog, openlog, closelog, setlogmask - control system log
SYNOPSIS
#include <syslog.h>
openlog(ident, logopt, facility)
char *ident;
syslog(level, message, parameters ... )
char *message;
closelog()
setlogmask(maskpri)
DESCRIPTION
Syslog arranges to write message onto the system log
maintained by syslogd(8). The message is tagged with a
priority level. The message looks like a printf(3) string
except that %m is replaced by the current error message
(collected from errno). A trailing new-line is added if
needed. This message will be read by syslogd(8) and written
to the system console, log files, or forwarded to syslogd on
another host as appropriate.
Priorities are encoded as a facility and a level. 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
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
should possibly be handled specially.
LOG_INFO Informational messages.
LOG_DEBUG Messages that contain information normally of
use only when debugging a program.
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syslog(3) DG/UX 4.30 syslog(3)
If syslog cannot pass the message to syslogd, it will
attempt to write the message on /dev/console if the LOG_CONS
option is set (see below).
If special processing is needed, openlog can be called to
initialize the log file. The parameter ident is a string
that is prepended to every message. Logopt is a bit field
indicating logging options. Current values for logopt 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 syslogd. This option is
safe to use in daemon processes that have no
controlling terminal since syslog will fork
before opening the console.
LOG_NDELAY Open the connection to syslogd 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 Do not wait for child processes forked to log
messages on the console. This option should
be used by processes that enable notification
of child termination via SIGCHLD, as syslog
may otherwise block waiting for a child whose
exit status has already been collected.
The facility parameter encodes a default facility to be
assigned to all messages that do not have an explicit
facility encoded:
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 ftpd(8), etc.
LOG_AUTH The authorization system: login(1), su(1),
getty(8), etc.
LOG_LPR The line printer spooling system: lp(1), etc.
LOG_LOCAL0 Reserved for local use. Similarly for
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syslog(3) DG/UX 4.30 syslog(3)
LOG_LOCAL1 through LOG_LOCAL7.
Closelog can be used to close the log file.
Setlogmask sets the log priority mask to maskpri and returns
the previous mask. Calls 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 including toppri is given
by the macro LOG_UPTO(toppri). The default allows all
priorities 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), syslog.conf(5), syslogd(8).
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