swift How to send &nil to func?

Question

func setupCircular(circularLayer:inout CAShapeLayer?){
    if (circularLayer == nil) {
        circularLayer = CAShapeLayer()
    }else{

    }
}
setupCircular(circularLayer: &nil)

how to write？

Answer 1

You cannot use a value as an inout parameter in Swift. You need to create a variable of type CAShapeLayer, assing it a nil value and use that as the input parameter to your function.

func setupCircular(circularLayer:inout CAShapeLayer?){
    if (circularLayer == nil) {
        circularLayer = CAShapeLayer()
    }else{

    }
}

var circ: CAShapeLayer? = nil
setupCircular(circularLayer: &circ)