> On Mar 29, 2019, at 2:51 PM, Alex Zavatone <z...@mac.com> wrote: > > Also, I seem to remember the esteemed Jens stating that as soon as a category > class is in your project, it applies to all objects instantiated from the > base class and we only had to do an import if we wanted to use the category > methods in the debugger. Please correct me if I am wrong here.
No, you have to #import the header if you want to use the category methods in a source file. At _compile_ time, when you call one of those methods the compiler needs to have seen a prior declaration of that method or it'll flag an error. Thus, you need to have #included the header file declaring the category. (The compiler _could_ go ahead and decide you know what's right, and just compile a call to that method anyway; back in the old days it used to, but that turned out to lead to lots of stupid runtime crashes caused by mistyped method names.) At _runtime_, the category patches the class implementation when your app starts, so its methods are available everywhere. —Jens _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
