I discovered this from stack traces of toll-free bridged calls. All CoreFoundation objects have an Objective-C isa pointer. For toll-free bridged objects, this pointer points to an Objective-C class which is a subclass of the corresponding class cluster public class, like for CFArray the subclass is called __NSCFArray. This Objective-C class maps calls from Objective-C public API to corresponding CoreFoundation calls.
All CoreFoundation functions that take toll-free-bridge-able objects detects if the argument passed in is CoreFoundation object. If Cocoa objects are used, base on the situation, either the object will be copied into its CoreFoundation counterpart, or the call will be mapped back to Cocoa. This entangled nature guaranteed that at least all toll-free bridging private Cocoa classes, their public base classes and NSObject are inside CoreFoundation binary, or the linker will be seriously confused. 发自我的 iPhone _______________________________________________ Gnustep-dev mailing list Gnustep-dev@gnu.org https://lists.gnu.org/mailman/listinfo/gnustep-dev