SYSLOG
Section: Linux Programmer's Manual (3)
Updated: 15 Feb 1994
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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 program. The string pointed
to by
ident
is added to each message, 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 section. 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 list 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 connection 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 program 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)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- PARAMETERS
-
- option
-
- facility
-
- level
-
- HISTORY
-
- SEE ALSO
-
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