On Fri, Nov 21, 2008 at 3:40 PM, Scott Thompson <[EMAIL PROTECTED]> wrote: > Technical QA 1405 concerns the creation of Objective-C methods that take > variable number of arguments... so called variadic methods. Happily the > mechanisms just use the standard C mechanisms (va_start and friends). > > That being the case, why is it that methods like arrayWithObjects: require > you to nil terminate the list of arguments? Is it simply tradition, or some > kind of optimization?
Without the nil, how would the method know when to stop fetching arguments with va_arg? This is true in C too, you have to have some way that tells you how many parameters are being passed and what types they are, and there are generally only two ways to do this: 1) Have the information encoded in the first parameter (like a printf format string) 2) Have some sentinel value marking the end of the list (like the nil passed to arrayWithObjects:) -- Clark S. Cox III [EMAIL PROTECTED] _______________________________________________ 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]
