syslog()

Arguments:

priority

The priority of the message; see Message levels, below.

message

The message that you want to write. This message is identical to a printf()-format string, except that %m is replaced by the current error message (as denoted by the global variable errno). A trailing newline is added if none is present.

The formatting characters that you use in the message determine any additional arguments.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The syslog() function writes message to the system message logger. The message is then written to the system console, log files, and logged-in users, or forwarded to other machines as appropriate. (See the syslogd command.)

The vsyslog() function is an alternate form in which the arguments have already been captured using the variable-length argument facilities of <stdarg.h>.

Message levels

The message is tagged with priority. Priorities are encoded as a facility and a level. The facility describes the part of the system generating the message:

LOG_KERN

Kernel messages.

LOG_USER

Random user-level messages.

LOG_MAIL

Mail system.

LOG_DAEMON

System daemons.

LOG_AUTH

Security/authorization messages.

LOG_SYSLOG

Messages generated internally by syslogd.

LOG_LPR

Line printer subsystem.

LOG_NEWS

Network news subsystem.

LOG_UUCP

UUCP subsystem.

LOG_CRON

Clock daemon.

LOG_AUTHPRIV

Security/authorization messages (private).

LOG_FTP

ftp daemon.

LOG_LOCAL0 through LOG_LOCAL7

Reserved for local use.

The level is selected from the following list (ordered from high to low):

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 (for example, hard device errors).

LOG_ERR

General errors.

LOG_WARNING

Warning messages.

LOG_NOTICE

Conditions that aren't error conditions, but should possibly be specially handled.

LOG_INFO

Informational messages.

LOG_DEBUG

Messages that contain information normally of use only when debugging a program.

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");

Classification:

POSIX 1003.1