I am writing my first objective-c daemon type process that works in the background. Everything it does needs to be logged properly.
I am fairly new to Apple stuff so I am not sure, what is the most common and/or best way to log activity? Does everyone simply log to a text file in their own special format, or use some sort of system call?
You should look at the Apple System Logger. ASL writes to the system log database (making it easy to query the log from Console.app or from within your own app) and additionally to one or more flat files (if you choose). Peter Hosey's introduction to the ASL is the best I'm aware of. ASL is a C-level API, but it's relatively easy to wrap in Objective-C if you'd like. I would recommend also taking a look at Google's Toolbox for Mac. Among many other goodies, it contains a GTMLogger facility that includes ASL support. I've ditched my home-grown ASL wrapper in favor of the GTMLogger.