[xhgdvjky]

I have worked on native Windows and Mac UI, and in my experience, Apple does document most symbols. It just does it really poorly. So percent of symbols documented is not a good metric.

MSDN is much much more thorough. MSDN usually tells you everything you need to confidently call a function... Apple docs tell you enough to start experimenting.

Apple tends to have good textbook style documentation that doesn't directly explain a symbol per se, but rather explains a topic e.g. how to write network code on a Mac. But these pages are usually outdated... like 10+ years outdated.