The GNU Objective-C runtime used to provide a different API, which we
call the “traditional” GNU Objective-C runtime API. Functions
belonging to this API are easy to recognize because they use a
different naming convention, such as
(traditional API) instead of
API). Software using this API includes the file
objc/objc-api.h where it is declared.
Starting with GCC 4.7.0, the traditional GNU runtime API is no longer available.