Forgot to copy list. On Tue, Mar 31, 2009 at 1:12 PM, Jim Correia <jim.corr...@pobox.com> wrote: > On Mar 31, 2009, at 1:32 PM, Patrick Burleson wrote: > >> I ran into something I don't quite understand and was hoping to get >> some enlightenment. There's a method defined on AudioPlayer that goes >> like this: >> >> - (id) initWithURL: (CFURLRef) fileURL; > > [...] > >> The question I have is on the line: >> >> AudioPlayer *thePlayer = [[AudioPlayer alloc] initWithURL: (NSURL >> *)fileURL]; >> > > +alloc returns an untyped (`id`) object. > > The compiler must consider all -initWithURL: methods that it has seen > declared. Since the frameworks provide -initWithURL:(NSURL *)url (and the > compiler doesn't know about the toll free bridging between NSURL and CFURL), > the warning is generated. >
I see with alloc returning (id) that it'd have to consider all the initWithURL's it knows about. The exact warning is: warning: passing argument 1 of 'initWithURL:' from incompatible pointer type If the compiler is considering all initWithURLs and only fails when it's not exactly NSURL *, then that would imply to me all other initWithURLs take NSURL *? Or is it ignoring that the AudioPlayer.h declares a version that takes CFURLRef? > You can cast the argument, as you have done above. You can also cast the > result of +alloc: > > AudioPlayer *thePlayer = [(AudioPlayer *)[AudioPlayer alloc] > initWithURL: fileURL]; > > A better solution, though, is to avoid being in this situation in the first > place. > > -initWithFoo:(Foo *)foo > -initWithFoo:(NSInteger)foo > > Avoid designing classes whose initializers which use identical names for > different types. > Thanks for the advice. I should file a Radar on this sample code to change it. Maybe to initWithCFURL. Or to make the change where all the classes hold it as NSURL * until needed by the C APIs and the object is cast to CFURLRef as needed. Thanks, Patrick _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
