syslog() generates a log message that will be distributed by the system logger. priority is a combination of the facility and the level, values for which are given in the next section. The remaining argument is the message to send, except that the two characters %m will be replaced by the error message string (strerror) corresponding to the present value of errno.
Table 1. syslog() Priorities (in descending order)
|LOG_EMERG||system is unusable|
|LOG_ALERT||action must be taken immediately|
|LOG_NOTICE||normal, but significant, condition|
Example 1. Using syslog()
On Windows NT, the syslog service is emulated using the Event Log.
Note: Use of LOG_LOCAL0 through LOG_LOCAL7 for the facility parameter of openlog() is not available in Windows.