Can someone give an example of a forward declaration in a C object for a normal class, and not for a category or protocol?

Question

Can someone give an example of a forward declaration in a C object for a normal class, and not for a category or protocol?

Answer 1

/* using a forward declaration of NSDocument, there no need for every source that encounters this header to include AppKit, allowing much faster compile times and reducing dependency changes for clients. of course, MONThang.m will need to include AppKit to use NSDocument - but the clients using MONThang do not need to import AppKit. */ @class NSDocument; // << the forward declaration @interface MONThang : NSObject { NSDocument * document; } @end