‘NSLog’ is unavailable: Variadic function is unavailable in swift

Question

If you declare var myString: NSString? as an optional then you need to make sure it has a value before you pass it to the NSLog.

So you could do it like this then NSLog("%@" , myString!). If myString is nil and you put ! the program will crash and you will get

fatal error: unexpectedly found nil while unwrapping an Optional value.

But if it has a value the program will continue as normal and print out

2016-10-03 10:26:25.077 Swift3.0[65214:1579363] Test

I wrote myString = "Test".

Another example as @Grimxn mentioned is the coalescing operator.

NSLog("%@", myString ?? "<nil>")