Swift throw from closure nested in a function

Question

I have a function that throws an error, in this function I have a inside a closure that I need to throw the error from it\'s completion handler. Is that possibl

Answer 1

That's not possible in this case - that completion handler would have to be declared with throws (and the method with rethrows) and this one is not.

Note that all that throwing is just a different notations for NSError ** in Objective-C (inout error parameter). The Objective-C callback doesn't have an inout parameter so there is no way to pass the error up.

You will have to use a different method to handle errors.

In general, NSError ** in Obj-C or throws in Swift don't play well with asynchronous methods because the error handling works synchronously.