I understand the historical context that lead to the creation of Glib (no C++ standard in the mid-'90s, no decent open Objective-C libraries, Stallman and most of the FOSS movement at the time harbouring a deep disgust towards C++ for some reason, etc), but it can't be pointed at as a good example of how to code in C - on the contrary, it's IMHO exactly what your C project shouldn't do. You've picked C because it's simple and clear, don't butcher it up with macros and weird hacks just to get a worse Objective-C.