Question

I wanna do pass by reference in ObjC.
Here is the illustration of the scenario:

// MainClass.h
@interface MainClass
{
    Board *board;
    OtherClass *other;
}
@end

// MainClass.m
@implementation MainClass

- (id)init
{
   if (self = [super init])
   {
      board = [[Board alloc] init];
      other = [[OtherClass alloc] initOtherClassWithBoard: board];
   }
   return self
}

@end

// Other class.h
@interface OtherClass
{
   Board *refBoard;
}
- (void)initOtherClassWithBoard: (Board*)ref;
@end

@implementation OtherClass

- (id)initOtherClassWithBoard: (Board*)ref
{
    if (self = [super init])
    {
       refBoard = ref;
    }
    return self;
}

@end

So my question is does my OtherClass is holding a reference Board from MainClass?
Or OtherClass’s Board is a copy but not a reference.
If I wanna do a reference then how should I change it?

EDIT:
What if I add this on both classes

@property (nonatomic, retain) Board *board;

Answer 1

You always refer to objects in Objective-C via pointers, a.k.a. references. Therefore, objects are always passed by reference in Objective-C.