I am trying to learn about syslog (and syslog-ng). I have a question: Where do the log messages come from? Does the kernel just spew messages all the time? If logging is not configured, do the messages just go nowhere? Does the programmer of a particular program decide the severity level (warn, info, etc) or does the system somehow classify the messages?
For instance, as a programmer, can I just arbitrarily decide to send a log message classified as, say, daemon.warn? Or am I limited to what types of messages I can send. How would a program actually send a log message? Would it use the "logger" command?