Passing a nil object to a function

Question

Hey guys,

I was wondering if objective C does any check to see if a pointer to an object is nil before calling the function.

For example, say I have a

myObject* ptr;

and initialize

ptr = nil;

and call

[self myFunction:ptr];

where myFunction is my own function and does no check to see if the object is nil. I heard somewhere that objective C will not call the function if it is nil? Is this true and would my code be safe?

The reason I ask is because I'm implementing a universal app, and have an UIView instance that will only work for the ipad. But, I do many function calls for this view, and instead of doing condition checks to see if it is an ipad before calling the function, it would be great if I could set the view as nil if it's an iphone.

Also, if the interface builder allocated the object and I set the pointer to nil, will there be a memory leak or will the builder know to dealloc the object?

Thanks

Answer 1

As for the memory, if you have the object in the NIB file and then set its outlet to nil in the code, there will be a memory leak. You should release the object and then set it to nil.

It might be a good idea in that case, though, to simply create the object if it's an iPad and leave the variable as nil if it's an iPhone. That way you don't have to deal with any stray references that may crop up if you create the object in the NIB file. That may or may not be an issue, but it's probably better to create conditionally rather than destroy conditionally.