On Wed, Jun 4, 2008 at 3:07 AM, Seth Willits <[EMAIL PROTECTED]> wrote: > On Jun 3, 2008, at 9:15 AM, j o a r wrote: > >>> Would it be sufficient to cast, like this? >>> : >>> return (NSData *)myData; >>> >>> Does this generalize to other non-collection classes, e.g., NSString? >> >> >> In the general case yes. > > I used to think that. Now I'm converting to making sure it truly is > returning an immutable object. There have been cases where I've changed it > under myself and run into problems. I figure if it says it's immutable, it'd > better be immutable.
There are two fairly different cases to consider. In one case, you're returning a pointer to a mutable instance variable. Returning a copy can be a very good idea here, because you might change the value when the caller doesn't expect it. In another case, you're returning a mutable temporary object. Since nobody else has a pointer to it, it can't change spontaneously, so copying it is fairly pointless. This looks to be the case that the original poster is in. Mike _______________________________________________ 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 [EMAIL PROTECTED]
