How to pass pointer to a reference as an argument to a function-Objective C

Question

In C++ we will pass the pointer to a function as

bool getData(REMOTE_ID msId,RsEvent*& pEvent);

How to declare this in Objective C?

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Answer 1

(By the way, you're not dealing with a pointer to a reference, but a reference to a pointer.) Can't you just use the same type annotation in the Objective-C method?

- (BOOL)getData:(REMOTE_ID)msId withEvent:(RsEvent*&)pEvent;

I think that should work, but if it doesn't, you can use a pointer to a pointer instead:

- (BOOL)getData:(REMOTE_ID)msId withEvent:(RsEvent**)pEvent {
  useEvent(*pEvent); // when using the event, you need to dereference the pointer
}

Send the -getData:withEvent: message with the address of your event:

[obj getData:SOME_ID withEvent:&event];

Answer 2

You need to use pointers to simulate reference in C (and Objective-C):

-(BOOL)getData:(REMOTE_ID)msId withEvent:(RsEvent**)pEvent {
   // do stuff with msId and *pEvent
}

and pass in the argument as a pointer:

RsEvent* event;
BOOl res = [foo getData:msId withEvent:&event];
...