Q:

how to pass variable arguments to another method? 

i have googled and came to know that how to use the variable arguments.  but i want to pass my variable arguments to another method.  i m getting errors.  how to do that ? 
-(void) aMethod:(NSString *) a, ... {
  [self anotherMethod:a]; 
  // i m doing this but getting error.  how to pass complete vararg to anotherMethod
}

A:

AFAIK ObjectiveC (just like C and C++) do not provide you with a syntax that allows what you directly have in mind. 
The usual workaround is to create two versions of a function.  One that may be called directly using ... and another one called by others functions passing the parameters in form of a va_list. 

..
[obj aMethod:@"test this %d parameter", 1337);
[obj anotherMethod:@"test that %d parameter", 666);
..

-(void) aMethod:(NSString *)a, ... 
{
    va_list ap;
    va_start(ap, a);

    [self anotherMethod:a withParameters:ap]; 

    va_end(ap);
}

-(void) anotherMethod:(NSString *)a, ...
{
    va_list ap;
    va_start(ap, a);

    [self anotherMethod:a withParameters:ap]; 

    va_end(ap);
}

-(void) anotherMethod:(NSString *)a withParameters:(va_list)valist 
{
    NSLog([[[NSString alloc] initWithFormat:a arguments:valist] autorelease]);
}

A:

You cannot pass variadic arguments directly.  But some of these methods provide an alternative that you can pass a va_list argument e.g.
#include <stdarg.h>

-(void)printFormat:(NSString*)format, ... {
   // Won't work:
   //   NSString* str = [NSString stringWithFormat:format];

   va_list vl;
   va_start(vl, format);
   NSString* str = [[[NSString alloc] initWithFormat:format arguments:vl] autorelease];
   va_end(vl);

   printf("%s", [str UTF8String]);
}

