What is the best way to get a listing of all users known on a system (even if they are only local domain ones, that is still useful)? Is this functionality exposed within Cocoa or should I look to the lower-level APIs?
It’s not part of Cocoa. Look at the man page for niutil
You may also want to give getpwent a try. man 3 getpwent
Will this work on OSX? I.e. is it NetInfo aware?
After further investigation, it appears as the the DirectoryService framework is the way to do this, correctly.
It is a pretty ugly API but Apple’s sample code is pretty useful.