Overriding a variadic method in objective-c

问题

When subclassing in objective-c, how can I forward a call to the superclass in the case of a variadic method. By what should I replace the ??? below to send all the objects I got?

- (void) appendObjects:(id) firstObject, ...
{
   [super appendObjects: ???];
}

回答1:

You can't. To safely pass all the variadic arguments, you need a method to accept a va_list.

In super,

-(void)appendObjectsWithArguments:(va_list)vl {
  ...
}

-(void)appendObject:(id)firstObject, ...
  va_list vl;
  va_start(vl, firstObject);
  [self appendObjectsWithArguments:vl];
  va_end(vl);
}

And use [super appendObjectsWithArguments:vl] when you override the method in the subclass.

回答2:

There is a good article on this at Cocoa with Love: Variable argument lists in Cocoa

回答3:

Try this:

- (void) appendObjects:(id) firstObject, ...
{
   va_list args = &firstObject;
   [super appendObjects: args];
}

If that doesn't do the trick, read the manual pages on varargs.

来源：https://stackoverflow.com/questions/3987209/overriding-a-variadic-method-in-objective-c