看到官方的一个例子不错，这里留记。

#import <Cocoa/Cocoa.h>

@interface NSMutableArray (variadicMethodExample)

- (void) appendObjects:(id) firstObject, ...; // This method takes a nil-terminated list of objects.

@end

@implementation NSMutableArray (variadicMethodExample)

- (void) appendObjects:(id) firstObject, ...
{
id eachObject;
va_list argumentList;
if (firstObject) // The first argument isn't part of the varargs list,
  {                                   // so we'll handle it separately.
  [self addObject: firstObject];
  va_start(argumentList, firstObject); // Start scanning for arguments after firstObject.
  while (eachObject = va_arg(argumentList, id)) // As many times as we can get an argument of type "id"
      [self addObject: eachObject]; // that isn't nil, add it to self's contents.
  va_end(argumentList);
  }
}

@end

最经常见到的应该是UIAlertView里用的了。

- (id)initWithTitle:(NSString *)title message:(NSString *)message delegate:(id /*<UIAlertViewDelegate>*/)delegate cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString *)otherButtonTitles, ... NS_REQUIRES_NIL_TERMINATION;

iOS ... NS_REQUIRES_NIL_TERMINATION