syslog.3c (2010 09)

syslog(3C) syslog(3C)

EXAMPLES

who logs a message regarding some sort of unexpected and serious error:

syslog(LOG_ALERT, "who: internal error 23");

ftpd uses openlog() to arrange to log its process ID, to log to the console if necessary, and to log in

the name of the daemon facility:

openlog("ftpd", LOG_PID|LOG_CONS, LOG_DAEMON);

Arrange to log messages only at levels LOG_ERR

and lower:

setlogmask(LOG_UPTO(LOG_ERR));

Typical usage of

syslog() to log a connection:

syslog(LOG_INFO, "Connection from host %s", CallingHost);

If the facility has not been set with

openlog(), it defaults to LOG_USER.

Explicitly set the facility for this message:

syslog(LOG_INFO|LOG_LOCAL2, "foobar error: %m");

WARNINGS

A call to syslog() has no effect unless the syslog daemon is running (see syslogd (1M)).

openlog()

does not copy and store the ident string internally; it stores only a character pointer. Therefore it is the

responsibility of the programmer to make sure that the ident argument points to the correct string until

the log ﬁle is closed.

AUTHOR

syslog() was developed by the University of California, Berkeley.