On Wed, Aug 20, 2008 at 7:56 PM, John C. Randolph <[EMAIL PROTECTED]> wrote: > > On Aug 20, 2008, at 4:15 PM, Torsten Curdt wrote: >> >> There was a common perception that NULL is not really the same as nil. But >> seems like in the end it really is (void*)0. > > They differ in type, not in value. > > "NULL" is (void *) 0. > "nil" is (id) 0. > "Nil" is (Class) 0.
This is true conceptually but not as far as their actual definition. NULL can be either 0 or (void *)0. Nil and nil don't have a formal definition, as Objective-C lacks a formal specification, but on my machine they are both defined to be either 0 in 32-bit or (0L) in 64-bit. But for maximal clarity you should use them as you specify above. > Personally, I prefer "if (!foo)" over "if (foo == nil)", because the latter > has the hazard of a typo that compiles. You can lose a fair bit of time > staring at "if (foo = nil)" before you spot the mistake. This hazard goes away if you turn on the appropriate warnings. I compile all of my code with "-W -Wall -Wno-unused-parameter", and it has caught much more than just this error over the years. 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]
