NAME
closelog, openlog, syslog - send messages to the system
logger
SYNOPSIS
#include <syslog.h>
void openlog( char *ident, int option, int facility
void syslog( int priority, char *format, ...)
void closelog( void )
DESCRIPTION
closelog() closes the descriptor being used to write to the
system logger. The use of closelog() is optional.
openlog() opens a connection to the system logger for a pro-
gram. The string pointed to by ident is added to each mes-
sage, and is typically set to the program name. Values for
option and facility are given in the next section. The use
of openlog() is optional; It will automatically be called by
syslog() if necessary, in which case ident will default to
NULL.
syslog() generates a log message, which will be distributed
by syslogd(8). priority is a combination of the facility
and the level, values for which are given in the next sec-
tion. The remaining arguments are a format, as in printf(3)
and any arguments required by the format, except that the
two character %m will be replaced by the error message
string (strerror) corresponding to the present value of
errno.
PARAMETERS
This section lists the parameters used to set the values of
option, facility, and priority.
option
The option argument to openlog() is an OR of any of these:
LOG_CONS
write directly to system console if there is an error
while sending to system logger
LOG_NDELAY
open the connection immediately (normally, the connec-
tion is opened when the first message is logged)
LOG_PERROR
print to stderr as well
LOG_PID
include PID with each message
facility
The facility argument is used to specify what type of pro-
gram is logging the message. This lets the configuration
file specify that messages from different facilities will be
handled differently.
LOG_AUTH
security/authorization messages (DEPRECATED Use
LOG_AUTHPRIV instead)
LOG_AUTHPRIV
security/authorization messages (private)
LOG_CRON
clock daemon (cron and at)
LOG_DAEMON
other system daemons
LOG_KERN
kernel messages
LOG_LOCAL0 through LOG_LOCAL7
reserved for local use
LOG_LPR
line printer subsystem
LOG_MAIL
mail subsystem
LOG_NEWS
USENET news subsystem
LOG_SYSLOG
messages generated internally by syslogd
LOG_USER(default)
generic user-level messages
LOG_UUCP
UUCP subsystem
level
This determines the importance of the message. The levels
are, in order of decreasing importance:
LOG_EMERG
system is unusable
LOG_ALERT
action must be taken immediately
LOG_CRIT
critical conditions
LOG_ERR
error conditions
LOG_WARNING
warning conditions
LOG_NOTICE
normal, but significant, condition
LOG_INFO
informational message
LOG_DEBUG
debug-level message
HISTORY
A syslog function call appeared in BSD 4.2.
SEE ALSO
logger(1), syslog.conf(5), syslogd(8)