Writtign to audit with an application

I was wondering if anyone had a good example of how to write to the audit log on linux for a custom application wanting to log events. Also how that would work. I found a little information but I have been unable to get anything to work properly. Does it write to the demon then write to the /var/log/auit/audit.log? Also how do yo set this up so not just any one or any process write to that log? Thanks, Frank