How can one NSWindow's ID be got

Question

I am new to Obj-c/Cocoa and want to know how to get one NSWindow's ID/number?

The following member variable of NSWindow is found on Apple's website.

var windowNumber: Int
The window number of the window’s window device.

However how to get it? Shall I just use

NSWindow aWindow;
[aWindow getWindowNumber];

Thanks a lot!

Answer 1

In Objective-C:

NSWindow* myWindow = ...;
NSInteger windowNumber = myWindow.windowNumber;

In Swift:

let myWindow = ...
let windowNumber = myWindow.windowNumber