If the method signature changes (unlikely for a system header, but possible if you're calling into your own code) then you're hosed. Or you could just mess up and copy/paste the wrong signature, or forget to change it.
Basically, it's pretty error-prone no matter what you do. Using Objective-C directly is much safer (and luckily you usually can, since ObjC is pretty much a drop-in replacement for C).
Re:OS X app in plain C
by mikeash on Thursday May 05, 2016 @09:22PM
(#11641039)
I totally agree on all counts here. The cast saves you from this one specific thing but there's plenty more to go wrong. I think some people may overestimate the difficulty of adding some ObjC wrappers to a plain C project.
Basically, it's pretty error-prone no matter what you do. Using Objective-C directly is much safer (and luckily you usually can, since ObjC is pretty much a drop-in replacement for C).